MedWorm provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest medical blog items that have been tagged with 'basic'. Sat, 03 Sep 2011 01:54:23 +0100 http://www.medworm.com/index.php?rid=5156943&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FtTMkRaxBBfc%2F I just returned from a 17-day, 3,000 km road trip with my family in Europe. When I travel I’m always on the lookout for virus-related information and I found some at the Deutsches Museum in Munich, Germany. This museum showcases science and technology – it has over 100,000 objects illustrating the historical progression of areas such as mining, atomic physics, water transport, electricity, and much more. Katharina Eisenacher made it her pick of the week on TWiV 102; she said it was a fabulous museum and now I understand why! Let me show and tell you about the virology that I found there. All of the photographs can be clicked for a larger view. On our way to the museum entrance we passed the gift shop, where two kits were prominently displayed in the window. The animal virus k... virology blog blogs http://www.medworm.com/rss/comments.php?id=5156943 Wed, 24 Aug 2011 17:47:38 +0100 5156943 http://www.medworm.com/index.php?rid=5094816&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F1fw6w28v_7s%2F Thirty years ago this month I did an experiment that set the course of my career, and provided an important step forward for animal virology. I showed that a cloned DNA copy of the poliovirus RNA genome is infectious in mammalian cells. When I arrived as a postdoctoral fellow in the laboratory of David Baltimore in 1979, the restrictions placed on cloning complete genomes from pathogenic viruses in bacterial plasmid vectors had just been lifted. Consequently David suggested that I construct a full-length DNA copy of the poliovirus RNA genome, decode the genetic information, and determine if the DNA is infectious. By the fall of 1980 I had produced three different plasmids which contained overlapping DNA copies of poliovirus RNA. For most of the next year I worked on deciphering the complet... virology blog blogs http://www.medworm.com/rss/comments.php?id=5094816 Wed, 03 Aug 2011 17:33:58 +0100 5094816 http://www.medworm.com/index.php?rid=5018724&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FS7FL_I-qVu8%2F Yesterday I terminated the last remaining mice in my small colony, including the line of poliovirus receptor transgenic mice that we established here in 1990. Remarkably, I had never written about this animal model for poliomyelitis which has played an important role in the work done in my laboratory. While I was still working on poliovirus as a postdoctoral fellow with David Baltimore, I became interested in how the virus causes disease. There were no convenient animal models to study poliovirus pathogenesis, so I began to think about the cellular receptor for the virus and how it could be used to make a mouse model for infection. When I moved to Columbia University Medical Center in 1982, I decided to identify the cellular gene for the poliovirus receptor. This work was carried out by th... virology blog blogs http://www.medworm.com/rss/comments.php?id=5018724 Tue, 12 Jul 2011 14:32:15 +0100 5018724 http://www.medworm.com/index.php?rid=4992114&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FLKECkCOaQIs%2F Analysis of poliovirus recovered from the stool of a patient with fatal poliomyelitis revealed that she had been infected with the virus 12 years earlier, probably when one of her children received the oral poliovirus vaccine. This case has the longest known incubation period for vaccine-derived poliomyelitis, and highlights our still rudimentary understanding of how poliovirus causes disease. The patient in this case, a 44 year old woman from Minnesota, had been diagnosed with common variable immunodeficiency (CVI) in 1991.  Patients with this disease lack B lymphocytes and therefore cannot produce antibodies that help control microbial infections. For example, individuals with CVI often develop chronic enterovirus infections. Furthermore, after receiving oral poliovirus vaccine, CVI pat... virology blog blogs http://www.medworm.com/rss/comments.php?id=4992114 Thu, 30 Jun 2011 17:44:49 +0100 4992114 http://www.medworm.com/index.php?rid=4968062&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F4EKFxy92D3M%2F The retrovirus XMRV arose during passage of a human prostate tumor in nude mice. The genomes of these mice contain two different proviral DNAs related to XMRV, pre-XMRV-1 and pre-XMRV-2, that recombined to produce XMRV that has been isolated from humans. Two other prostate cancer cell lines also contain mouse gammaretroviruses that are not XMRV. These viruses may have entered the prostate tumor cells during xenograft passage in immunocompromised mice. The discovery of infectious XMRV in the prostate tumor cell line 22Rv1 prompted the examination of other prostate tumor cell lines for the presence of murine gammaretroviruses. Antisera against Moloney murine leukemia virus were used to screen 72 cell lines by immunohistochemistry for the presence of murine gammaretroviruses. Three human pr... virology blog blogs http://www.medworm.com/rss/comments.php?id=4968062 Thu, 23 Jun 2011 22:07:51 +0100 4968062 http://www.medworm.com/index.php?rid=4997536&cid=t_108260_88_f&fid=38129&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2Flifeinthefastlane%2FWZHV%2F%7E3%2Fi5up-SjFC0Q%2F This one's for our medical student friends... and anyone else fighting the axis of evil! Understanding axis is one of the keys to understanding ECGs. Super Axis Man (SAM) is here to help! (Source: Life in the Fast Lane) Life in the Fast Lane blogs http://www.medworm.com/rss/comments.php?id=4997536 Thu, 23 Jun 2011 09:29:03 +0100 4997536 http://www.medworm.com/index.php?rid=4883757&cid=t_108260_129_f&fid=27216&url=http%3A%2F%2Flifewithadhd.com%2Fadhd-medication%2Fbest-medication-for-adhd-time-for-three-basic-questions.php In Britain, 6,350 prescriptions for ADHD drugs for hyperactive and ADD children are written every week. That is an enormous number and as parents begin to question what IS the best medication for ADHD, more and more conflicting views come to the surface. However we can ask ourselves three basic questions before deciding which road to go down. ADHD new medication has not changed much, in spite of many advances. First question is what side effects are going to upset my child? Impossible question to answer as every child is different. I know one girl who was on ADHD meds from the age of 6 to 19 and ended up almost anorexic. Many children have decreased appetite and sometimes indulge in binge eating to compensate. Some children are troubled by sleeping problems. I know one 9 year old child who... Life With ADHD blogs http://www.medworm.com/rss/comments.php?id=4883757 Sat, 28 May 2011 23:00:00 +0100 4883757 http://www.medworm.com/index.php?rid=4871355&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F2LnQ9MMrxr0%2F Contemporary human viruses most likely originated by cross-species transmission from non-human animals. Examples include HIV-1, which crossed from chimpanzees to humans, and SARS coronavirus, which originated in bats. Since the 1989 discovery of hepatitis C virus (classified as a hepacivirus in the family Flaviviridae) the origin of the virus been obscure. During the characterization of respiratory infections of domestic dogs, a virus was discovered that is the most genetically similar animal virus homolog of HCV. HCV is a substantial human pathogen: 200 million people worldwide are chronically infected and are at risk for the development of hepatocellular carcinoma. The source of HCV is unknown because there are no closely related animal virus homologs, but the hunt for related viruses ha... virology blog blogs http://www.medworm.com/rss/comments.php?id=4871355 Thu, 26 May 2011 02:02:42 +0100 4871355 http://www.medworm.com/index.php?rid=4862629&cid=t_108260_109_f&fid=34750&url=http%3A%2F%2Fpsychcentral.com%2Fblog%2Farchives%2F2011%2F05%2F25%2Fthe-critical-thinker-academy-2-interview-with-kevin-delaplante%2F This is part two of a two-part interview of Kevin deLaplante, a professor of philosophy and founder of The Critical Thinker Academy. Check out part one here. What is your favorite book on critical thinking? I often get requests for book recommendations. It’s hard because critical thinking requires so many different kinds of skill development, and no single book is going to cover everything. Also, people are usually interested in specific issues or topics, and once I know what those are it’s easier to recommend sources. My “starter kit” recommendation is to pick a good introductory book on basic argumentation and fallacies written from a logic/philosophy perspective, plus a good introductory book on the psychology of reasoning and decision making (something in the “biases ... World of Psychology blogs http://www.medworm.com/rss/comments.php?id=4862629 Wed, 25 May 2011 13:58:39 +0100 4862629 http://www.medworm.com/index.php?rid=4847956&cid=t_108260_87_f&fid=39187&url=http%3A%2F%2Fgetbetterhealth.com%2Finsect-killing-fungus-may-provide-basis-for-new-multiple-sclerosis-treatment%2F2011.05.20 A very well-written review of an orally-active drug for multiple sclerosis has just appeared in the April 25th issue of the Journal of Natural Products, a joint publication of the American Chemical Society and the American Society of Pharmacognosy. The review, Fingolimod (FTY720): A Recently Approved Multiple Sclerosis Drug Based on a Fungal Secondary Metabolite, is co-authored by Cherilyn R. Strader, Cedric J. Pearce, and Nicholas H. Oberlies. In the interest of full disclosure, the latter two gentlemen are research collaborators of mine from Mycosynthetix, Inc. (Hillsborough, NC) and the University of North Carolina at Greensboro. My esteemed colleague and senior author, Dr. Oberlies, modestly deflected my request to blog about the publication of this review. So, I am instead writing thi... Better Health blogs http://www.medworm.com/rss/comments.php?id=4847956 Fri, 20 May 2011 18:00:24 +0100 4847956 http://www.medworm.com/index.php?rid=4840508&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FdSQp61hbfzc%2F For extra credit in my recently concluded virology course, I asked students to summarize a virology finding in the style of this blog. I received many excellent submissions which I plan to post here in the coming months. by Amanda Carpenter In 1983, identical twin boys simultaneously received a contaminated blood transfusion immediately after birth, and were subsequently diagnosed with HIV-1. Years later, one of the twins is faring very well and has a near normal immune system, while the other is in poor health and has experienced many complications. How could the same virus, infecting two individuals at the same time, with the same genetic background, yield such different clinical courses? This unfortunate natural experiment has allowed researchers to study viral evolution while holding h... virology blog blogs http://www.medworm.com/rss/comments.php?id=4840508 Tue, 17 May 2011 14:12:31 +0100 4840508 http://www.medworm.com/index.php?rid=4742151&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FtrJDCC5fq7w%2F Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease or Lou Gehrig’s disease, is a fatal disorder of unknown etiology. The disease involves degeneration of motor neurons, leading to paralysis, respiratory failure, and death within five years. A viral etiology for ALS has been suggested but never proven. Retroviruses have been considered because they cause motor neuron disease in mice, and HIV-1 and HTLV-1 cause ALS-like symptoms in humans. Sera from some ALS patients have been shown to contain elevated levels of reverse transcriptase, an enzyme found in retrovirus particles. RNAs encoding this enzyme have now been found in the brains of ALS patients, and their origin appears to be the human endogenous retrovirus HERV-K. Reverse transcriptase is a retroviral enzyme ... virology blog blogs http://www.medworm.com/rss/comments.php?id=4742151 Fri, 22 Apr 2011 16:40:03 +0100 4742151 http://www.medworm.com/index.php?rid=4696637&cid=t_108260_88_f&fid=38129&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2Flifeinthefastlane%2FWZHV%2F%7E3%2FiE7n_E9lXCg%2F The amazing animated version of Tim Minchin's amazing 9 minute beat poem, Storm, can now be seen on the web. Right here even! (Source: Life in the Fast Lane) Life in the Fast Lane blogs http://www.medworm.com/rss/comments.php?id=4696637 Sat, 09 Apr 2011 10:24:59 +0100 4696637 http://www.medworm.com/index.php?rid=4676800&cid=t_108260_88_f&fid=38129&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2Flifeinthefastlane%2FWZHV%2F%7E3%2FkM7DGCYSedg%2F Is it possible to summarise all of human pathology into 140 characters or less? Michelle Johnston (aka @Eleytherius) thinks so... (Source: Life in the Fast Lane) Life in the Fast Lane blogs http://www.medworm.com/rss/comments.php?id=4676800 Tue, 05 Apr 2011 00:00:08 +0100 4676800 http://www.medworm.com/index.php?rid=4658103&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FHSlTcUoZ53E%2F Last week we discussed the second known virophage, but we didn’t have any explanation of why such viruses might evolve. This week we have the discovery of a third virophage, hints of many more, and a hypothesis for what they might be doing in the global ecosystem. The newest virus eater is called Organic Lake virophage (OLV), for the body of water in Antarctica where it was identified. Antarctic Lakes are well suited for metagenomic analyses (nucleotide sequences produced from environmental samples) because they are dominated by microbes and typically sustain few multicellular eukaryotes. For example, a metagenomic study of Lake Limnopolar, another Antarctic lake, revealed many novel eukaryotic and ssDNA viruses.Nucleotide sequence analysis of water samples taken from Organic Lake ... virology blog blogs http://www.medworm.com/rss/comments.php?id=4658103 Thu, 31 Mar 2011 00:50:51 +0100 4658103 http://www.medworm.com/index.php?rid=4658583&cid=t_108260_136_f&fid=37846&url=http%3A%2F%2Fhealthinfoispower.wordpress.com%2F2011%2F03%2F30%2F2011-aacr-annual-meeting-select-ovarian-cancer-presentations-abstracts-available-online%2F The 102nd American Association For Cancer Research (AACR) Annual Meeting will be held from Saturday, April 2 through Wednesday, April 6, 2011, at the Orange County Convention Center located in Orlando, Florida.  Select ovarian cancer presentations and abstracts are available online. The 102nd American Association For Cancer Research (AACR) Annual Meeting will be held from [...] (Source: Libby's H*O*P*E*) Libby's H*O*P*E* blogs http://www.medworm.com/rss/comments.php?id=4658583 Wed, 30 Mar 2011 20:23:54 +0100 4658583 http://www.medworm.com/index.php?rid=4621845&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F2PzXjJ9iI48%2F A second virophage has been identified. The name does not signify a virus that infects another virus – it means virus eater. The story of virophages begins with the giant mimivirus, originally isolated from a cooling tower in the United Kingdom. It is the largest known virus, with a capsid 750 nanometers in diameter and a double-stranded DNA genome 1.2 million base pairs in length. If these statistics are not sufficiently impressive, consider that shortly after its discovery, an even larger related virus was discovered and called mamavirus. These huge viruses replicate in amoeba such as Acanthamoeba; in this host they form large, cytoplasmic ‘factories’ where the DNA replicates and new virions are assembled. While examining mamavirus infected Acanthamoeba polyphaga, inves... virology blog blogs http://www.medworm.com/rss/comments.php?id=4621845 Tue, 22 Mar 2011 21:36:44 +0100 4621845 http://www.medworm.com/index.php?rid=4565642&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2Fx5LOBfPuqJw%2F We have just completed lecture #13 in my Columbia University virology course, which means that we are now at the halfway mark. In the first eleven lectures we covered basic aspects of viral replication in cell culture, including virus entry into cells, genome replication, and assembly. The remainder of the course is concerned with viral infection of a host, and will cover topics such as pathogenesis, immunity, immunization, antivirals, and evolution. All the virology lectures are available as videocasts (slides and audio) either at the course website, or at iTunes University. Below is a list of lectures that I have given so far in the course, with links to the videocast (.mp4 or .wmv files). To download the videocast, right click the link and save the file to your hard drive. Virology Lec... virology blog blogs http://www.medworm.com/rss/comments.php?id=4565642 Tue, 08 Mar 2011 22:28:51 +0100 4565642 http://www.medworm.com/index.php?rid=4527772&cid=t_108260_109_f&fid=34750&url=http%3A%2F%2Fpsychcentral.com%2Fblog%2Farchives%2F2011%2F02%2F27%2Fthink-like-a-skeptic-part-2%2F I was a presenter at the JP Fitness Summit in Kansas City in 2009, where I spoke about the importance of exercising skepticism in your life, whether you’re a fitness expert or anyone else. You can read my first article on the topic here. Here are some additional notes from my lecture at that event. I hope to be able to help readers understand the importance of relying on logic and how to do this more often in everyday life, and, in essence, how to think like a skeptic. The Concise English Oxford Dictionary defines “logic” as the science of reasoning, proof, thinking or inference. In the structure of a logical argument, one or more premises leads to a conclusion (a conclusion that could be true even if the argument is invalid). To sharpen critical thinking skills, it is im... World of Psychology blogs http://www.medworm.com/rss/comments.php?id=4527772 Sun, 27 Feb 2011 19:06:22 +0100 4527772 http://www.medworm.com/index.php?rid=4522146&cid=t_108260_109_f&fid=34750&url=http%3A%2F%2Fpsychcentral.com%2Fblog%2Farchives%2F2011%2F02%2F25%2F6-steps-to-living-a-good-happy-and-long-life%2F Compassion. Gratitude. Conscientiousness. Being humble. A little stress to keep you energized and motivated. Using common sense. Hanging out with the people that are doing healthy things. Having a stable relationship. You might think the secret to a long and happy life was hidden in a book or could be found by following that famous media guru, Oprah. The truth is, a long life and happiness are not obtained by doing extraordinary things or looking for that magical “dream job” (or dream spouse, for that matter). Research has shown — most recently by psychologists Friedman and Martin in The Longevity Project (2010) — that getting to a long life is really just a combination of simple, everyday things and an approach to life that some might say emphasizes a sense of resi... World of Psychology blogs http://www.medworm.com/rss/comments.php?id=4522146 Fri, 25 Feb 2011 15:46:57 +0100 4522146 http://www.medworm.com/index.php?rid=4460182&cid=t_108260_150_f&fid=35777&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FPharmalot%2F%7E3%2FcNF2uULPpF8%2F According to legend, academic researchers are good at discovering underlying mechanisms and pathways of disease, but less so at applied research for discovering drugs that can treat disease. Now, though, a new study in the New England Journal of Medicine debunks this myth - public sector research institutions were involved in developing more than 20 percent of new, innovative drugs approved between 1990 and 2007. This figure was derived by examining a newly constructed patent database for meds approved by the FDA after 1962 and identifying pertinent patents filed by PSRIs - defined as universities, research hospitals, nonprofit research institutes, and federal labs. From there, the researchers determined whether patents were for applied research. They found that PSRIs contributed to the di... Pharmalot blogs http://www.medworm.com/rss/comments.php?id=4460182 Thu, 10 Feb 2011 15:31:55 +0100 4460182 http://www.medworm.com/index.php?rid=4460187&cid=t_108260_151_f&fid=35818&url=http%3A%2F%2Frecoveryissexy.com%2Fpoor-emotional-recognition-by-addicts-alcoholics%2F Drug-abusers Have Difficulty in Recognizing Negative Emotions such as Wrath, Fear and SadnessUniversity of Granada scientists have been the first to analyze the relation between drug abuse and recognition of basic emotions (happiness, surprise, wrath, fear, sadness and disgust) by drug-abusers. Thus, the study revealed that drug-abusers have difficulty to identify negative emotions by their facial expression: wrath, disgust, fear and sadness.Further, regular abuse of alcohol, cannabis and cocaine usually affects abusers’ fluency and decision-making. Consuming cannabis and cocaine negatively affects working memory and reasoning. Similarly, cocaine abuse is associated to alterations in inhibition.For the purpose of this study, researchers carried out a psychological evaluation (with thinki... Recovery Is Sexy.com blogs http://www.medworm.com/rss/comments.php?id=4460187 Thu, 10 Feb 2011 14:56:00 +0100 4460187 http://www.medworm.com/index.php?rid=4393886&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FfWpMmrtT29s%2F My virology course at Columbia University, Biology W3310, has begun. This course, which I taught for the first time in 2009, is aimed at advanced undergraduates and will be taught at the Morningside Campus of Columbia University. Columbia University encompasses two principal campuses: the historic, neoclassical campus in the Morningside Heights neighborhood and the modern Medical Center further uptown, in Washington Heights. The two are separated by fifty-two city blocks, a distance of over two miles and 20-30 minutes by subway. My laboratory is at the Medical Center, where I’ve taught a variety of virology courses over the years. However, until last year, a virology course had not been offered at the Morningside Heights campus since the late 1980s. This is a serious omission for a f... virology blog blogs http://www.medworm.com/rss/comments.php?id=4393886 Mon, 24 Jan 2011 19:46:44 +0100 4393886 http://www.medworm.com/index.php?rid=4382236&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FdqxPNmlSYDg%2F Chris Upton, a contributor to the virology toolbox, has raised an important point about multiplicity of infection: Perhaps this is a place to bring up particle to pfu ratio? The above is great for when talking about phage, for example, when the ratio approaches 1. But with something like polio when it can be very high (>1000 ??), then it’s not that all cells don’t receive “a particle” at MOI=1 – but that they don’t get an “infectious dose”. Not sure how to say it better – enough to initiate an infection. So why does polio require 1000 virions to make an infectious dose? I don’t buy the idea that most of the particles are not “viable”. If we take the titer of a virus preparation (in plaque forming-units per millilite... virology blog blogs http://www.medworm.com/rss/comments.php?id=4382236 Fri, 21 Jan 2011 13:11:03 +0100 4382236 http://www.medworm.com/index.php?rid=4342737&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FuLm1tCudeRQ%2F (MOI) is a frequently used term in virology which refers to the number of virions that are added per cell during infection. If one million virions are added to one million cells, the MOI is one. If ten million virions are added, the MOI is ten. Add 100,000 virions, and the MOI is 0.1. The concept is straightforward. But here is the tricky part. If you infect cells at a MOI of one, does that mean that each cell in the cutlure receives one virion? The answer is no. Here is another way to look at this problem: imagine a room containing 100 buckets. If you threw 100 tennis balls into that room – all at the same time – would each bucket get one ball? Most likely not. How many tennis balls end up in each bucket, or the number of virions that each cell receives at different MOI, is d... virology blog blogs http://www.medworm.com/rss/comments.php?id=4342737 Thu, 13 Jan 2011 14:57:25 +0100 4342737 http://www.medworm.com/index.php?rid=4337541&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ftraffic.libsyn.com%2Ftwiv%2Fderek_smith.mp4 Derek Smith, Professor of Infectious Disease Informatics, University of Cambridge, U.K., has developed a method for visualizing antigenic evolution by creating two-dimensional maps in a process called antigenic cartography. These maps are made with data that provide information on the antigenic properties of the pathogen. In the case of influenza virus, the data come from measuring the ability of an antiviral antibody to inhibit hemagglutination – binding of virions to red blood cells. Such maps show how amino acid changes can affect antibody binding to virus particles, which cannot be done by comparing nucleotide sequences of different virus isolates. By charting influenza virus strains in this way, it should be possible to better understand genetic and antigenic evolution. I discussed ... virology blog blogs http://www.medworm.com/rss/comments.php?id=4337541 Fri, 07 Jan 2011 16:05:04 +0100 4337541 http://www.medworm.com/index.php?rid=4309239&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FbeReX4M3uAY%2F A strong argument that the novel human retrovirus XMRV is not a laboratory contaminant is the the finding that viral DNA is integrated in chromosomal DNA of prostate tumors. Why does this result constitute such strong proof of viral infection? Establishment of an integrated copy of the viral genome – the provirus – is a critical step in the life cycle of retroviruses. Proviral DNA is transcribed by cellular RNA polymerase II to produce the viral RNA genome and the mRNAs required to complete the replication cycle. Without proviral DNA, retroviral replication cannot proceed. To produce proviral DNA, the retroviral RNA genome is converted to a double-stranded DNA by the viral enzyme reverse transcriptase. This step occurs in the cytoplasm. Specific and efficient insertion of�... virology blog blogs http://www.medworm.com/rss/comments.php?id=4309239 Tue, 04 Jan 2011 14:00:33 +0100 4309239 http://www.medworm.com/index.php?rid=4309618&cid=t_108260_88_f&fid=38129&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2Flifeinthefastlane%2FWZHV%2F%7E3%2FjP9fR2-7Vhk%2F The Australian Resuscitation Council has release its 2011 resuscitation guidelines and flowcharts. (Source: Life in the Fast Lane) Life in the Fast Lane blogs http://www.medworm.com/rss/comments.php?id=4309618 Mon, 03 Jan 2011 12:24:24 +0100 4309618 http://www.medworm.com/index.php?rid=4636111&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fplayer.wizzard.tv%2Fplayer%2Fo%2Fj%2Fx%2F129313689372%2Fconfig%2Fk-baeb08ff45d4b757%2Fuuid%2Froot%2Fheight%2F340%2Fwidth%2F600%2Fepisode%2Fk-34862d35a68254bf.m4v On my recent trip to record TWiV #111 at Florida Gulf Coast University, I visited Rich Condit in Gainesville. There he told me a story about how the bacteriophage T7 polymerase/promoter system was developed. It’s an interesting tale that demonstrates how important scientific advances often have convoluted roots. You can watch the video below or download a high-definition (720p) version (585 MB .mov). The combination of bacteriophage T7 RNA polymerase and its cognate promoter sequence allows the production of specific RNAs either in vitro or in cells. In many laboratories this system is used to synthesize infectious viral RNA from cloned DNAs. In the example shown, a DNA copy of of the poliovirus RNA genome has been cloned into a bacterial plasmid. The promoter sequence for T7 RNA p... virology blog blogs http://www.medworm.com/rss/comments.php?id=4636111 Tue, 28 Dec 2010 13:07:52 +0100 4636111 http://www.medworm.com/index.php?rid=4287412&cid=t_108260_87_f&fid=39187&url=http%3A%2F%2Fgetbetterhealth.com%2Freal-meaning-at-christmas%2F2010.12.24 Every day I go to work and spend time with suffering people. They come to me for help and for comfort. They open up to me with problems that they would not tell anyone else. They put trust in me — even if I am not able to fix their problems. I serve as a source of healing, but I also am a source of hope. Christmas is a moving season for many of the same reasons. No, I am not talking about the giving of gifts or the time spent with family. I am not talking about traditions, church services, or singing carols. I am not even talking about what many see as thereal meaning of Christmas: Mary, Joseph, shepherds, wise men, and baby Jesus. The Christmas story most of us see in pictures or read about in story books is a far cry from the Biblical account. The story we see and hear is... Better Health blogs http://www.medworm.com/rss/comments.php?id=4287412 Fri, 24 Dec 2010 22:00:14 +0100 4287412 http://www.medworm.com/index.php?rid=4248751&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FIKdHua-OwRs%2F During the replication of retroviruses, a double-stranded DNA copy of the viral RNA genome is synthesized by reverse transcription and integrated into the genomes of the infected cell. When retroviral DNA is integrated into the DNA of germ line cells, it is passed on to future generations in Mendelian fashion as an endogenous provirus. Until very recently, retroviruses were the only known endogenous viruses. This honor has now been extended to other RNA viruses, and to circoviruses and parvoviruses, which possess single-stranded DNA genomes. Such integration events constitute a fossil record from which it is possible to determine the age of viruses. The first non-retroviral endogenous virus described was bornavirus, a virus with a negative-stranded RNA genome. Bornaviral sequences were fou... virology blog blogs http://www.medworm.com/rss/comments.php?id=4248751 Fri, 10 Dec 2010 13:00:10 +0100 4248751 http://www.medworm.com/index.php?rid=4245011&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FsoDQyobQdZg%2F Influenza researcher Peter Palese visited yesterday and spoke about “Pandemic influenza: Past and Future”. A key part of his talk was a review of his efforts to produce a universal influenza vaccine which protects against all strains. He used the following graph to make the point that when influenza pandemic strains emerge, there is insufficient time to deliver a vaccine using current technology. Image source: CIDRAP The graph depicts the percentage of visits for influenza-like illness (ILI – the red line) and distribution of the swine-origin influenza vaccine (blue line) from September 2009 to May 2010 in the US. At the peak of ILI at the end of October 2009, fewer than 20 million doses of vaccine had been shipped. By the time 120 million doses had been distributed, infe... virology blog blogs http://www.medworm.com/rss/comments.php?id=4245011 Thu, 09 Dec 2010 17:15:05 +0100 4245011 http://www.medworm.com/index.php?rid=4245310&cid=t_108260_88_f&fid=38129&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2Flifeinthefastlane%2FWZHV%2F%7E3%2FiEWyIYEbmWY%2F The most important distinction is whether the rhythm is ventricular (VT) or supraventricular (SVT with aberrancy), as this will significantly influence how you manage the patient. SVTs usually respond well to AV-nodal blocking drugs, whereas patients with VT may suffer precipitous haemodynamic deterioration if erroneously administered an AV-nodal blocking agent. (Source: Life in the Fast Lane) Life in the Fast Lane blogs http://www.medworm.com/rss/comments.php?id=4245310 Thu, 09 Dec 2010 04:09:30 +0100 4245310 http://www.medworm.com/index.php?rid=4230079&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FqIaQq5WxUww%2F A salt-loving (halophilic) bacterium which can grow in medium containing arsenic instead of phosphorus has been selected from the microbial community of Mono Lake in California. Arsenic (As) is a chemical analog of phosphorus and is usually toxic because it can enter metabolic pathways in the place of phosphorus. It appears to be incorporated into macromolecules of the bacterium (called GFAJ-1) that normally contain phosphorus, such as nucleic acids and proteins. The identification of bacteria that can utilize arsenic has many metabolic and evolutionary implications. I’m wondering whether there are viruses that infect bacteria such as GFAJ-1. It has been suggested that Mono Lake contains organisms that are biologically distinct from all others so far discovered on Earth. In other w... virology blog blogs http://www.medworm.com/rss/comments.php?id=4230079 Sat, 04 Dec 2010 15:07:39 +0100 4230079 http://www.medworm.com/index.php?rid=4636113&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2Ffib0071.flv I joined Marc Pelletier, Andre Nantel, and George Farr on episode 71 of Futures in Biotech for a conversation about the 1000 genome project, the billion dollar human proteome, how antibodies block viral infection, and capturing anti-matter. Download audio FiB #71 (42 MB .mp3, 87 minutes) Download video (211 MB .mp4) (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=4636113 Tue, 30 Nov 2010 20:39:39 +0100 4636113 http://www.medworm.com/index.php?rid=4175696&cid=t_108260_87_f&fid=39187&url=http%3A%2F%2Fgetbetterhealth.com%2Falcoholic-energy-drinks-health-hazards-and-bannings%2F2010.11.17 In this video, you will see an interview I was asked to do on November 11th on local TV about alcoholic energy drinks like Four Loko that has been in the news recently. I talk about the potential harmful effects of the ingredients of a product like this. As of this posting there have been a number of states, colleges, and universities who have taken steps to ban these type of beverages.   At the end of the interview, I talk about how I don’t think banning a product like this is going to solve the problem. In the article “Banning Four Loko Doesn’t Solve Problems,” Alex Belz from The North Wind explains: It seems these health officials are either unaware of or choosing to ignore the fact that combining a caffeinated beverage with an alcoholic one is a time-tested... Better Health blogs http://www.medworm.com/rss/comments.php?id=4175696 Wed, 17 Nov 2010 15:00:00 +0100 4175696 http://www.medworm.com/index.php?rid=4158813&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FTmOWer8-iJc%2F Antibodies are an important component of the host defense against viral infection. These molecules, produced 7-14 days after infection, neutralize viral infectivity, thereby limiting the spread of infection. Antibodies are thought to neutralize viral infectivity in several ways: by forming noninfectious aggregates that cannot enter cells, or by blocking virion attachment to cells or uncoating (figure). A new mechanism has just joined this list, in which antibody bound virions are degraded in the cell cytoplasm. A cytoplasmic protein called TRIM21 (tripartite motif-containing 21) was recently found to bind with high affinity to the conserved regions of antibody molecules. The presence of this activity in many mammalian species suggested that there could be ways that antibodies operate withi... virology blog blogs http://www.medworm.com/rss/comments.php?id=4158813 Thu, 11 Nov 2010 18:34:51 +0100 4158813 http://www.medworm.com/index.php?rid=4133018&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FsT8eTTPVLfQ%2F How large is the zoonotic pool – all the animal viruses that could one day infect humans? Assuming that there are 50,000 vertebrates on earth, each with 20 viruses, the number is one million – probably a vast underestimate. Determining just how many viruses exist in a variety of animal species is technically feasible, limited only by the number of hosts that can be sampled. A study of the virome of several North America bats reveals that these animals – which constitute 25% of all the known mammalian species – harbor a very large collection of viral sequences. Advances in nucleotide sequencing technologies (deep sequencing) have made it possible in recent years to study the virome – the genomes of all viruses in a host – in human blood, diarrhea, and res... virology blog blogs http://www.medworm.com/rss/comments.php?id=4133018 Wed, 03 Nov 2010 09:04:46 +0100 4133018 http://www.medworm.com/index.php?rid=4119080&cid=t_108260_109_f&fid=34750&url=http%3A%2F%2Fpsychcentral.com%2Fblog%2Farchives%2F2010%2F10%2F28%2Fhow-does-that-make-you-feel-five-myths-about-psychology%2F Walk into any bookstore and you will find racks and racks of books claiming to cure any number of major psychological problems with easy solutions. Want to lose weight? Try hypnosis. Want to get rich? Just visualize your goals and eventually you will achieve whatever you want. The truth is that the mind is an incredibly powerful and complex instrument and we are only beginning to learn its the true potential. Although psychology may assist in explaining our rational decision-making and emotional makeup, there is still plenty of guesswork out there. Below are five commonly believed myths about psychology. 5 Psychology Myths Subliminal Advertisements Work. While advertisers everywhere would like to believe this is true, there is no scientific data to back up the theory that split-second m... World of Psychology blogs http://www.medworm.com/rss/comments.php?id=4119080 Thu, 28 Oct 2010 11:54:17 +0100 4119080 http://www.medworm.com/index.php?rid=4065001&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FzmYU5OnEXyI%2F The need to re-formulate the influenza virus vaccine in response to viral antigenic drift and shift makes for complex logistics of vaccine production and administration. Surveillance programs must be conducted each year to identify strains that are likely to predominate and cause disease. Wouldn’t it be simpler if a single vaccine could be developed that would confer protection against a broad range of viral strains? Results from the past year suggest that such a vaccine might be closer than previously thought. The influenza viral HA protein consists of a globular head atop a stem that is embedded in the virion membrane (figure). Most protective antibodies are directed against the head of the HA molecule. Rare antibodies that block infection with a broad range of influenza virus strains ... virology blog blogs http://www.medworm.com/rss/comments.php?id=4065001 Wed, 13 Oct 2010 14:35:54 +0100 4065001 http://www.medworm.com/index.php?rid=4055717&cid=t_108260_87_f&fid=39187&url=http%3A%2F%2Fgetbetterhealth.com%2Fbasic-health-education-not-so-basic%2F2010.10.10 The past two weeks I’ve been the “dayfloat” resident on the cardiology inpatient service. With the 30-hour-shift work “restrictions” placed on medical residents, there has been a need for new systems of care to ensure the safety of newly admitted patients and cardiology dayfloat is one of them. My job is to round with the post-call team, help them get out of the hospital on time, and then take care of their patients through the end of the work day. It’s a fairly easy rotation, as they go, though because I “float” from one team to another without patients of my own, it’s also not the most satisfying. Towards the end of my two week rotation, I was paged by a nurse because a patient’s husband wanted an update on his wife’s condition. Glancing at my “signout” — a on... Better Health blogs http://www.medworm.com/rss/comments.php?id=4055717 Sun, 10 Oct 2010 20:00:29 +0100 4055717 http://www.medworm.com/index.php?rid=4022916&cid=t_108260_88_f&fid=38129&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2Flifeinthefastlane%2FWZHV%2F%7E3%2FenMWGrocPFY%2F Working on some anatomy teaching sessions today, and I stumbled across the online version of Instant Anatomy - a fantastic website with great illustrations to aid the learning of Human Anatomy with diagrams, podcasts and revision questions. (Source: Life in the Fast Lane) Life in the Fast Lane blogs http://www.medworm.com/rss/comments.php?id=4022916 Fri, 01 Oct 2010 06:42:24 +0100 4022916 http://www.medworm.com/index.php?rid=3998432&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F1uU7_uXX9N0%2F All known virus particles can be placed into one of two general categories: enveloped or non-enveloped. Viruses that fall into the former category are characterized by a lipid membrane derived from the host cell, and one or more nuclecapsid proteins that interact with the viral genome. A virus that infects an archaeal host may constitute a new category of enveloped viruses. It comprises a membrane vesicle that encloses a circular ssDNA genome which is devoid of nucleic acid-binding nucleoproteins. Examples of enveloped virions that contain nucleoproteins are shown in the figure below. These include influenza virus (left), a simple retrovirus (center), and a togavirus (right). The influenza virion contains segments of viral RNA bound to four different proteins. Retroviral RNA is bound to a... virology blog blogs http://www.medworm.com/rss/comments.php?id=3998432 Fri, 24 Sep 2010 02:09:07 +0100 3998432 http://www.medworm.com/index.php?rid=3895936&cid=t_108260_109_f&fid=34750&url=http%3A%2F%2Fpsychcentral.com%2Fblog%2Farchives%2F2010%2F08%2F23%2Fobama-kanazawa-endogamy-and-religion%2F A recent blog entry by Satoshi Kanazawa, an evolutionary psychologist, recently came across my desk that made the outrageous claim that one cannot chose one’s religion. If one’s family is a Muslim, you will be too, no matter what you actually practice — genetically speaking. He relates this piece of news by suggesting that Obama cannot choose to be a Christian, because his family was a Muslim. He suggests that, genetically, Obama is a Muslim no matter what he practices. If this doesn’t pass the basic logic smell test for you, then you’re not alone. Like other world religions, Islam not only is a religion but also comprises largely endogamous ethnic groups. When a group of individuals remain largely or entirely endogamous (marry only other members of the group ... World of Psychology blogs http://www.medworm.com/rss/comments.php?id=3895936 Mon, 23 Aug 2010 16:27:31 +0100 3895936 http://www.medworm.com/index.php?rid=3868738&cid=t_108260_87_f&fid=39187&url=http%3A%2F%2Fgetbetterhealth.com%2Fan-emergency-medicine-myth%2F2010.08.15 I’ve internalized all the dogma of medicine, for good and bad. When I was an EMT, green as a twig in an ER, I learned the basics: For any wound with hair employ the razor, and get the hair away from the laceration so the doc could do a good closure. So, employment week #3: Eyebrow laceration? Shaved that sucker clean off. ER doc freaked out, and I learned some medical dogma: Don’t shave eyebrows, they don’t grow back. Heard it later, too — all the way through training, in fact. (more…) *This blog post was originally published at GruntDoc* (Source: Better Health) Better Health blogs http://www.medworm.com/rss/comments.php?id=3868738 Sun, 15 Aug 2010 12:00:29 +0100 3868738 http://www.medworm.com/index.php?rid=3858201&cid=t_108260_109_f&fid=34750&url=http%3A%2F%2Fpsychcentral.com%2Fblog%2Farchives%2F2010%2F08%2F11%2F7-tips-for-changing-therapists%2F Psychotherapy is a great treatment option for virtually any mental disorder or mental health concern, as well as life and relationship issues. Decades’ worth of research have proven its effectiveness, at least when you’re working with an experienced therapist who knows their stuff and uses empirically-backed techniques. But what happens when you need to change therapists? We all need to change therapists from time to time, so how do you start over with a new therapist? Where do you begin? What do you do? And what do you look for in your new therapist? Changing therapists can be a daunting, anxiety-inducing process. There is no “right” time to change therapists. You do it when you feel like you’re treading water with your current therapist, or you’re just... World of Psychology blogs http://www.medworm.com/rss/comments.php?id=3858201 Wed, 11 Aug 2010 16:30:51 +0100 3858201 http://www.medworm.com/index.php?rid=3816448&cid=t_108260_107_f&fid=35026&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FTheTreeOfLife%2F%7E3%2FLpfJM5_CjjE%2Fhuman-genome-project-oversold-sure-but.html Well, the piling on the human genome project continues, it seems at an accelerating pace.  I think most of this comes from the fact that we are in the range of the 10 year anniversary right now.   Here are some examples of recent stories suggesting the human genome project (or projects, if you count the public effort and Craig Venter's effort as separate) have had little benefit: 7/31/10: The Human Genome Project: 10 Years Later, Progress but Still a Puzzle - WNYC. Interesting piece by Sarah Kate Kramer discussing the limited clinical value of the HGP.  Includes some criticisms of personalized genomic medicine.  7/29/10: Spiegel interview with Craig Venter with the headline "We have learned nothing from the genome".  Has lots of interesting tidbits. &nbsp... The Tree of Life blogs http://www.medworm.com/rss/comments.php?id=3816448 Tue, 03 Aug 2010 16:18:29 +0100 3816448 http://www.medworm.com/index.php?rid=3946233&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FVsA8GRuYb4Q%2F The illustration at left depicts a virion – the infectious particle that is designed for transmission of the nucleic acid genome among hosts or host cells. A virion is not the same as a virus. I define virus as a distinct biological entity with five different characteristics. Others believe that the virus is actually the infected host cell. The idea that virus and virion are distinct was first proposed by Bandea in 1983. He suggested that a virus is an organism without a cohesive morphological structure, with subsystems that are not in structural continuity: Viruses are presented as organisms which pass in their ontogenetic cycle through two distinctive phenotypic phases: (1) the vegetative phase and (2) the phase of viral particle or nucleic acid. In the vegetative phase, considered... virology blog blogs http://www.medworm.com/rss/comments.php?id=3946233 Fri, 23 Jul 2010 02:12:51 +0100 3946233 http://www.medworm.com/index.php?rid=3732931&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F3ti2E5M06Sc%2F Readers of virology blog often request explanations of specific experimental techniques. Methods such as complement fixation, deep sequencing, ELISA, PCR and many others are frequently mentioned on this blog without discussion. To do so would interrupt the scientific discourse and make for lengthly posts. To remedy this shortcoming, I have added a new tab to the first page of virology blog called Virology Toolbox. This page will be populated with explanations of experimental techniques used for the study of viruses. Today’s technique is the western blot. Western blot analysis (also known as immunoblotting) is used to detect a specific protein in a cell, tissue, organ, or body fluid. The technique depends on the reaction of an antibody with a protein that is immobilized on a thin memb... virology blog blogs http://www.medworm.com/rss/comments.php?id=3732931 Wed, 07 Jul 2010 16:59:34 +0100 3732931 http://www.medworm.com/index.php?rid=3726797&cid=t_108260_155_f&fid=39206&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FStempath%2F%7E3%2F8l9YGkMPoUk%2Ffollow-up-on-obamas-ethics-tough-on.html The NIH has rejected 47 stem cell lines carrying a variety of disease causing mutations reports the Chicago Sun-Times.  The lines developed from preimplantation genetic diagnosis at the Reproductive Genetics Institute failed to receive the "OK" for federal funding because of a problem in the patient consent form.  I reported on the initial controversey in a post a few weeks ago. The lines are potentially a gold mine for researchers studying the relationship between the mutated gene and the development of diseases such as muscular dystrophy and huntington's disease.  The stem cell lines will not be available for federally funded research and studies utilizing these lines must now be funded soley through private resources. (Source: StemPath) StemPath blogs http://www.medworm.com/rss/comments.php?id=3726797 Mon, 05 Jul 2010 15:44:00 +0100 3726797 http://www.medworm.com/index.php?rid=3666243&cid=t_108260_155_f&fid=39206&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FStempath%2F%7E3%2Fpp3clO48yN0%2Flink-between-liver-development.html This study generated beautiful images that depict the ductular reactions becoming bipolarized into hepatocytic and cholangiocytic lineages. An investigation into the transcription factors that are expressed in these ductular reactions confirmed that developmental genes are reactivated and similarly showed differences in expression profiles between injury groups. I have previously posted on the role of stem cells in tumorigenesis, and hepatic stem cells are a prime suspect for the originating cell of hepatocellular carcinoma (HCC). Last year, Yamashita et al, found an aggressive subset of HCC that contains EpCAM+ cells with the molecular signature of hHpSC. The authors of this study further demonstrated that the EpCAM+ cells are a tumor initiating population and that molecular knockdown of... StemPath blogs http://www.medworm.com/rss/comments.php?id=3666243 Wed, 16 Jun 2010 13:46:00 +0100 3666243 http://www.medworm.com/index.php?rid=3665732&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F8RUa0r5vUC8%2F The influenza virus neuraminidase (NA) protein is required for virus release from the cell, a property exploited by the antiviral drugs oseltamivir (Tamiflu) and zanamavir (Relenza). During clinical testing of oseltamivir in 2001, some individuals shed drug-resistant viruses with an amino acid change from histidine to tyrosine (H274Y) in NA. Such viruses are not inhibited by oseltamivir because the amino acid change leads to  decreased binding of the drug. But these viruses replicated less well in cell culture, and had reduced infectivity in ferrets. It was concluded that oseltamivir resistant influenza virus mutants would not spread in the population. Why was this conclusion wrong? During the 2008-09 flu season oseltamivir resistant influenza H1N1 viruses with the H274Y change began to s... virology blog blogs http://www.medworm.com/rss/comments.php?id=3665732 Tue, 15 Jun 2010 20:06:03 +0100 3665732 http://www.medworm.com/index.php?rid=3648231&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2Ffib60.mp3 When infection with hepatitis C virus goes from acute to chronic, severe liver disease may occur which requires organ transplantation. Nearly 200 million people are chronically infected with HCV, necessitating approaches to preventing and treating infections. No HCV vaccine is available, and current antiviral therapy consists of administration of interferon plus ribavirin, a combination that is effective about half the time and is associated with undesirable side effects. New antiviral compounds that target a viral protease and RNA polymerase are currently in clinical trials may eventually reach the market. But our experience with HIV-1 has shown that combinations of three drugs are the most effective for derailing the emergences of drug resistant viruses. The third target for HCV could be... virology blog blogs http://www.medworm.com/rss/comments.php?id=3648231 Wed, 09 Jun 2010 16:17:13 +0100 3648231 http://www.medworm.com/index.php?rid=3629242&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FpFYQ0lulg4g%2F Robert H. Silverman, one of the authors on the study implicating the new human retrovirus XMRV as an etiologic agent of chronic fatigue syndrome, has written an excellent review article on the current status of research on the virus. The article is behind a paywall at Nature Reviews Urology, so I’ll provide a summary of the salient points. The article begins with a description of how XMRV DNA was isolated from surgically removed prostate tumor tissue. Sequence analysis of three strains showed that the virus is most closely related to xenotropic and polytropic murine leukemia viruses and hence was named xenotropic murine leukemia virus-related virus, or XMRV. Five lines of evidence indicate that XMRV is not a laboratory contaminant: XMRV was detected in RNA isolated from human prosta... virology blog blogs http://www.medworm.com/rss/comments.php?id=3629242 Fri, 04 Jun 2010 03:26:12 +0100 3629242 http://www.medworm.com/index.php?rid=3636046&cid=t_108260_155_f&fid=39206&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FStempath%2F%7E3%2Fz7e1o_mJCns%2Fprimer-on-stem-cell-biology.html Questions such as "So what makes this a stem cell?" and "what's the difference between progenitors and stem cells anyway?" have been asked to me before by both attending physicians and residents or fellows.   Stem cell biology and regenerative medicine is truly a multidisciplinary field and one of the greatest advances in science and technology.  This post is a primer on stem cell biology focuses mostly on adult tissue stem cells and is intended for physicians interested in becoming involved in regenerative medicine.  The following terms are a necessary starting point for discussing the facets that underlie this field and over time I intend to expand upon the concepts presented here. Stem cells are inherently different from terminally diff... StemPath blogs http://www.medworm.com/rss/comments.php?id=3636046 Wed, 02 Jun 2010 08:10:00 +0100 3636046 http://www.medworm.com/index.php?rid=3621312&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FBiC3ccYPYjg%2F One property of viruses that is difficult to conceptualize is their small size. I can tell you that viruses can be anywhere from 20 to 750 nanometers in diameter, but that’s not easy to visualize, even for those of us who routinely work with small measurements. One way to demonstrate how small viruses are is to compare them with animal and plant cells, bacteria, proteins, molecules, and atoms, as shown below: But even comparisons of this type fall short because they do not provide a readily grasped real-life reference. A better way was suggested by my colleague Karla Kirkegaard: Start by multiplying the size of viruses and humans one million times. A supine human would then extend from California to Colorado. At this scale, a cell would be about the size of a lecture hall. Depending... virology blog blogs http://www.medworm.com/rss/comments.php?id=3621312 Tue, 01 Jun 2010 17:28:48 +0100 3621312 http://www.medworm.com/index.php?rid=3607233&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2Fl-d4XP8wBrM%2F A serious shortcoming of current influenza virus vaccines is the need to reformulate them every year or two as the virus undergoes antigenic drift. Many virologists have been captivated by the idea of a more universal vaccine that would endure longer, perhaps a decade or more. The identification of a conserved domain in the stalk region of the viral HA protein that gives rise to antibodies that block infection by 10 HA subtypes was a step in this direction. The next phase in the development of a new vaccine, the production of an antigen that confers broader protection, has been achieved using an HA molecule lacking the globular head. The vast majority of antibodies that block influenza virus infection are directed against the globular head of the HA, the protein essential for attachment t... virology blog blogs http://www.medworm.com/rss/comments.php?id=3607233 Thu, 27 May 2010 20:12:25 +0100 3607233 http://www.medworm.com/index.php?rid=3585250&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F025_W3310_10.mp4 In the final lecture of my virology course, Professor Dickson Despommier weaves a story about the arrival of West Nile virus to the United States in the summer of 1999. This is a special treat that you won’t want to miss, as Prof. Despommier is a wonderful storyteller. Download: .wmv (422 MB) | .mp4 (108 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3585250 Fri, 21 May 2010 13:00:59 +0100 3585250 http://www.medworm.com/index.php?rid=3581396&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FP0IXq90nJzQ%2F An important question about the retrovirus XMRV, which has been implicated in prostate cancer and chronic fatigue syndrome, is where the virus replicates in humans. Such information would provide clues about how infection might be transmitted. To date the virus has been detected in malignant prostate cells and in the peripheral blood mononuclear cells and plasma of patients with CFS. A new study reveals that XMRV is present in respiratory secretions. Polymerase chain reaction was used to detect XMRV in 267 respiratory samples taken from German patients. One group comprised sputum and nasal swab specimens from 75 travelers from Asia who had respiratory tract infections. The second group consisted of 31 bronchoalveolar lavage samples from patients with chronic obstructive pulmonary disease, ... virology blog blogs http://www.medworm.com/rss/comments.php?id=3581396 Wed, 19 May 2010 15:51:27 +0100 3581396 http://www.medworm.com/index.php?rid=3577106&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FNFRSkuXeW-w%2F Google Flu Trends uses analysis of large numbers of search queries to track influenza-like illness in a population. The idea is that the frequency of certain queries correlates with the percentage of physician visits in which a patient presents with influenza-like symptoms. Google claims that it can accurately estimate the level of weekly influenza activity in each region of the United States. But a recent study shows that Google Flu Trends is not as accurate at estimating rates of laboratory-confirmed influenza as surveillance carried out by the CDC. Google Flu Trends and CDC surveillance results were compared for the period of  2003 – 2008. As reported at the 2010 American Thoracic Society Conference, the greatest deviation of Google Flu Trends from CDC surveillance occurred durin... virology blog blogs http://www.medworm.com/rss/comments.php?id=3577106 Tue, 18 May 2010 17:28:44 +0100 3577106 http://www.medworm.com/index.php?rid=3577107&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F024_W3310_10.mp4 Download: .wmv (350 MB) | .mp4 (96 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3577107 Tue, 18 May 2010 16:52:30 +0100 3577107 http://www.medworm.com/index.php?rid=3563646&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F023_W3310_10.mp4 Download: .wmv (346 MB) | .mp4 (91 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3563646 Fri, 14 May 2010 13:00:51 +0100 3563646 http://www.medworm.com/index.php?rid=3555808&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FvUzenTmDe0g%2F Bovine viral diarrhea virus is an economically important animal pathogen that may cause a fatal gastrointestinal disease in beef and dairy herds. Infection of a fetus with this virus during the first trimester leads to the birth of animals that are persistently infected for life. Some animals remain healthy, while others develop severe mucosal disease. The lethal outcome is a consequence of RNA recombination that produces a cytopathic virus. Pathogenicity of bovine viral diarrhea virus is associated with the synthesis of a the viral protein NS3. This protein is not produced by the noncytopathic virus that persistently infects cows for life. Absence of the protein is due to failure to cleave the precursor of NS3, called NS2-3. In cells infected with the cytopathic, disease-causing virus, NS... virology blog blogs http://www.medworm.com/rss/comments.php?id=3555808 Tue, 11 May 2010 21:34:06 +0100 3555808 http://www.medworm.com/index.php?rid=3551987&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F022_W3310_10.wmv Download: .wmv (393 MB) | .mp4 (102 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3551987 Mon, 10 May 2010 16:47:38 +0100 3551987 http://www.medworm.com/index.php?rid=3542264&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F021_W3310_10.wmv Download: .wmv (349 MB) | .mp4 (90 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3542264 Fri, 07 May 2010 14:37:27 +0100 3542264 http://www.medworm.com/index.php?rid=3529454&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F020_W3310_10.wmv Get the Flash Player to see this player. var s1 = new SWFObject("https://media.dreamhost.com/mp5/player.swf","ply","512","384","9","#FFFFFF"); s1.addParam("allowfullscreen","true"); s1.addParam("allowscriptaccess","always"); s1.addParam("flashvars","file=http://www.virology.ws/020_W3310_10.flv"); s1.write("mvcontainer"); Download: .wmv (314 MB) | .mp4 (82 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3529454 Tue, 04 May 2010 00:42:55 +0100 3529454 http://www.medworm.com/index.php?rid=3526969&cid=t_108260_160_f&fid=36189&url=http%3A%2F%2Fwww.skinmdblog.com%2F42%2Fbasic-skin-care-remember-the-sunblock%2F Melanin is what makes our skin brown. This pigment is also the skin’s primary defense against the harmful rays of the sun. Being people of color, the high amount of melanin in our skin is the reason why the incidence of skin cancer is almost nil and is why our skin ages more slowly than Caucasians. Given these facts why else do we need to wear sunblock and why do we need to use it daily even though we’re practically in the shade all the time? New studies have come up showing that even intermittent exposures to the sun as short as a few minutes (like that 5 minute walk to that nearby cafe) may do sub-clinical damage to our skin. Slowly and with time these damages add up and become visible as wrinkles, pigmentation changes, dullness, increase in pore size etc. Luckily, there are numerous... Skin MD blogs http://www.medworm.com/rss/comments.php?id=3526969 Mon, 03 May 2010 13:42:25 +0100 3526969 http://www.medworm.com/index.php?rid=3519143&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FIqQ945qpG2E%2F It has been estimated that approximately one hundred trillion bacteria colonize the human intestine. That’s about ten times the number of cells that constitute the entire human body. These bacteria are believed to have a mutualistic symbiotic relationship with their hosts. What is known about the viral communities that inhabit our alimentary tract? The vast majority of DNA viruses in the human gut are bacteriophages, which infect the resident bacteria. The most plentiful RNA viruses in our feces are plant viruses, and the most abundant is pepper mild mottle virus (PMMV). This plant virus is present at high levels, up to  109 virions per gram. The virus has been identified in 12 of 18 fecal specimens taken from healthy humans in the USA and Singapore. Pepper mild mottle virus is pres... virology blog blogs http://www.medworm.com/rss/comments.php?id=3519143 Thu, 29 Apr 2010 17:09:03 +0100 3519143 http://www.medworm.com/index.php?rid=3515136&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F019_W3310_10.wmv Get the Flash Player to see this player. var s1 = new SWFObject("https://media.dreamhost.com/mp5/player.swf","ply","512","384","9","#FFFFFF"); s1.addParam("allowfullscreen","true"); s1.addParam("allowscriptaccess","always"); s1.addParam("flashvars","file=http://www.virology.ws/019_W3310_10.flv"); s1.write("mvcontainer"); Download: .wmv (352 MB) | .mp4 (89 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3515136 Thu, 29 Apr 2010 01:34:27 +0100 3515136 http://www.medworm.com/index.php?rid=3507869&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FrOlKe_XILPk%2F Viruses can be transmitted to completely new host species that they have not previously infected. Usually host defenses stop the infection before any replication and adaptation can take place. On rare occasions, a novel population of viruses arises in the new host. These interspecies infections can sometimes be deduced by sequence analyses, providing a glimpse of the amazing and unpredictable paths of virus evolution. One example is a plant virus that switched hosts and infected vertebrates. Circoviruses infect vertebrates and have small, circular, single-stranded DNA genomes. Nanoviruses have the same genome structure, but infect plants. The genes encoding one of the viral proteins – called the Rep protein – appear to be hybrids, and share significant sequence similarity. They... virology blog blogs http://www.medworm.com/rss/comments.php?id=3507869 Tue, 27 Apr 2010 03:05:54 +0100 3507869 http://www.medworm.com/index.php?rid=3501388&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F018_W3310_10.wmv Download: .wmv (330 MB) | .mp4 (72 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3501388 Sat, 24 Apr 2010 11:43:40 +0100 3501388 http://www.medworm.com/index.php?rid=3490276&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FmEKbafeJIUM%2F All mammalian genomes contain genes encoding Apobec proteins. Several members of this protein family (the name stands for apolipoprotein B mRNA editing complex) are induced by interferon and are intrinsic antiretroviral proteins. Apobec proteins inhibit the replication of XMRV, a new human retrovirus associated with prostate cancer and chronic fatigue syndrome. During retroviral replication, Apobec proteins are packaged into newly synthesized retrovirus particles (illustrated). They exert their antiviral effect when Apobec-containing virions infect a new cell. As the viral reverse transcriptase begins to copy viral RNA into DNA, Apobec removes an amine group from cytosines in single stranded DNA, a process called deamination.  The consequence of deamination is that cytosine is changed to ... virology blog blogs http://www.medworm.com/rss/comments.php?id=3490276 Tue, 20 Apr 2010 18:29:46 +0100 3490276 http://www.medworm.com/index.php?rid=3486625&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FeYY8hlOy30U%2F Download: .wmv (322 MB) | .mp4 (91 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3486625 Tue, 20 Apr 2010 14:20:43 +0100 3486625 http://www.medworm.com/index.php?rid=3475475&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F016_W3310_10.wmv Download: .wmv (331 MB) | .mp4 (68 MB) Presented by guest lecturer Saul Silverstein, Ph.D. Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3475475 Fri, 16 Apr 2010 11:25:56 +0100 3475475 http://www.medworm.com/index.php?rid=3467447&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FtUXBKGLO1-w%2F Deep sequencing – which identified a viral contaminant of the rotavirus vaccine Rotarix - could have revealed the presence of simian virus 40 (SV40) in the poliovirus vaccine, had the technique been available in the 1950s. Exposure of over 100 million Americans to SV40, and many more worldwide, could have been avoided, as well as the debate about the role of this monkey virus in human cancer. SV40 was discovered by Maurice Hilleman in 1960 as a contaminant of poliovirus vaccine. It was present in batches of both the Salk and Sabin poliovirus vaccines produced and distributed from 1954 to 1963. The source was the rhesus and cynomolgous monkey kidney cells used to produce the vaccine. Even more troubling was the observation that SV40 could cause tumors in hamsters. By 1963 screenin... virology blog blogs http://www.medworm.com/rss/comments.php?id=3467447 Tue, 13 Apr 2010 21:34:33 +0100 3467447 http://www.medworm.com/index.php?rid=3453446&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FdgubNvhu0Tg%2F The contamination of the rotavirus vaccine Rotarix with porcine circovirus 1 DNA was revealed by deep sequencing. The same technique was also used to demonstrate that oral poliovirus vaccine does not contain viruses that can cause poliomyelitis. The oral poliovirus vaccine strains developed by Albert Sabin (pictured) were licensed in the United States in 1962, and over the next 37 years immunization with these vaccines lead to the eradication of poliomyelitis in this country. During that period, the vaccine was responsible for 5-10 cases of poliomyelitis each year, either in recipients of the vaccine or in their contacts. Some of these individuals have sued the manufacturers of the vaccine, claiming that they made a defective product. OPV contains three different poliovirus strains which w... virology blog blogs http://www.medworm.com/rss/comments.php?id=3453446 Thu, 08 Apr 2010 20:51:45 +0100 3453446 http://www.medworm.com/index.php?rid=3443512&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FHyz-u3g1UBE%2F Xenotropic murine leukemia virus related virus (XMRV) has been implicated in prostate cancer and chronic fatigue syndrome (CFS). Because XMRV is a retrovirus, it might be susceptible to antiviral drugs that are licensed for the treatment of AIDS. AZT (azidothymidine) was previously found to block XMRV replication. A screen of forty-five compounds reveals that XMRV replication is inhibited by raltegravir and three other drugs. The authors studied the effect of 45 compounds on the replication of XMRV in cell lines derived from human breast (MCF-7) and prostate (LNCaP) cancers. Twenty-eight of the drugs have been approved for use in humans, including treatment of HIV-1 infection. The drugs tested include nucleoside and non-nucleoside reverse-transcriptase inhibitors, and integrase and proteas... virology blog blogs http://www.medworm.com/rss/comments.php?id=3443512 Wed, 07 Apr 2010 15:44:48 +0100 3443512 http://www.medworm.com/index.php?rid=3443513&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F014_W3310_10.mp4 Download: .wmv (343 MB) | .mp4 (94 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3443513 Wed, 07 Apr 2010 14:26:47 +0100 3443513 http://www.medworm.com/index.php?rid=3411008&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F4yhKCjVXutM%2F The US Food and Drug Administration does not want Rotarix, the rotavirus vaccine, to be used because it contains porcine circovirus 1 DNA. If complete copies of the circovirus genome were present, would they constitute a potential threat to recipients? Put another way, is circovirus DNA infectious? Here is the information you need to answer this question. The circovirus genome is a circular, single stranded DNA molecule (pictured). To infect a cell, the two viral proteins encoded in the DNA must be produced. To produce proteins, mRNA must be synthesized from the viral DNA. Single-stranded DNA cannot be copied  into mRNA; the DNA must be double-stranded. The circovirus particle consists of a protein shell surrounding the viral DNA. There are no other components in the virion. During infec... virology blog blogs http://www.medworm.com/rss/comments.php?id=3411008 Fri, 26 Mar 2010 21:07:54 +0100 3411008 http://www.medworm.com/index.php?rid=3407961&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F013_W3310_10.wmv Download: .wmv (327 MB) | .mp4 (90 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3407961 Fri, 26 Mar 2010 02:45:33 +0100 3407961 http://www.medworm.com/index.php?rid=3389159&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F0319-fib56.mp4 I joined Marc Pelletier on episode 56 of Futures in Biotech for a conversation with Stanford University School of Medicine Professor Karla Kirkegaard.  We talked about RNA viruses – where they came from, where they are going, and Dr. Kirkegaard’s unique approach to discovering antiviral drugs. Don’t miss this episode: Dr. Kirkegaard is a brilliant and eloquent virologist who makes complicated science easy to understand. Video courtesy of Team ODTV Download video (114 MB .mp4) (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3389159 Mon, 22 Mar 2010 15:02:42 +0100 3389159 http://www.medworm.com/index.php?rid=3358616&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2Fd2XR0dpw4qY%2F The second RNA segment of some influenza virus strains encodes a protein called PB1-F2 that might contribute to virulence. Speaking about the 2009 pandemic H1N1 strain, Peter Palese noted that “If this virulence marker is necessary for an influenza virus to become highly pathogenic in humans or in chickens, then the current swine virus doesn’t have what it takes to become a major killer.” If the pandemic virus mutated so that the PB1-F2 protein is produced, would it become a killer? The PB1-F2 protein is not produced in cells infected with the 2009 H1N1 strain because there are three translation stop codons at nucleotide positions 12, 58, and 88.  To determine if this protein plays a role in virulence, the second RNA segment of the A/California/04/2009 H1N1 strain was genetically al... virology blog blogs http://www.medworm.com/rss/comments.php?id=3358616 Fri, 12 Mar 2010 13:32:15 +0100 3358616 http://www.medworm.com/index.php?rid=3358617&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F012_W3310_10.wmv Download: .wmv (369 MB) | .mp4 (77 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3358617 Fri, 12 Mar 2010 02:09:47 +0100 3358617 http://www.medworm.com/index.php?rid=3346257&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FN9Rvj0JXo0I%2F Today my virology class is taking a midterm examination. To prepare for this in-class test, I provided the students with a study guide highlighting what I believe to be the main concepts that they should learn from each lecture.  Once all the students have taken the exam, I’ll post it here for everyone else to take. To prepare for that day, you might want to start by reviewing the first half of the course, which covered the infectious cycle. Virology W3310 is held in Hamilton Hall (image), an original McKim, Mead, and White building. Lecture 1 – What is a virus? Viruses were originally discovered because of their size, relative to known bacterial cells. Tobacco mosaic virus was called a “filterable infectious agent” by this criterion. Why is size not a good defining feature ... virology blog blogs http://www.medworm.com/rss/comments.php?id=3346257 Mon, 08 Mar 2010 20:05:12 +0100 3346257 http://www.medworm.com/index.php?rid=3321989&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F011_W3310_10.wmv Download: .wmv (354 MB) | .mp4 (104 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3321989 Tue, 02 Mar 2010 03:07:35 +0100 3321989 http://www.medworm.com/index.php?rid=3318374&cid=t_108260_87_f&fid=36438&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FCato-at-liberty%2F%7E3%2F3YYXAMKhxZc%2F By Chris Moody Countdown: A quick rundown of some of the best (and worst) ideas for health care reform. The case for high-deductible health insurance:  “Of every dollar spent on health care in this country, just 13 cents is paid for by the person actually consuming the goods or services….As long as someone else is paying, consumers have every reason to consume as much health care as is available….This all but guarantees that health care costs and spending will continue their unsustainable path. And that is a path leading to more debt, higher taxes, fewer jobs and a reduced standard of living for all Americans.” McDonald v. Chicago: A new Supreme Court battle over the right to bear arms. Reality: The real housing crisis was the bubble, not the bust. “Was... Cato-at-liberty blogs http://www.medworm.com/rss/comments.php?id=3318374 Mon, 01 Mar 2010 16:58:01 +0100 3318374 http://www.medworm.com/index.php?rid=3314453&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F010_W3310_10.wmv Download: .wmv (331 MB) | .mp4 (71 MB) Presented by guest lecturer Saul Silverstein, Ph.D. Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3314453 Sat, 27 Feb 2010 15:58:15 +0100 3314453 http://www.medworm.com/index.php?rid=3311288&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FmTG92pSAQiQ%2F The suggestion that the retrovirus XMRV is the etiologic agent of chronic fatigue syndrome (CFS) arose from a study in which the virus was found in 68 of 101 US patients. The virus was not detected in two independent studies of 186 and 170 CFS patients in the United Kingdom. A new Dutch study has also failed to reveal XMRV sequences in 32 CFS patients. The subjects of the Dutch study were part of a 298 member cohort. All patients fulfilled the Oxford criteria for CFS and reported debilitating fatigue for at least one year. Cryopreserved peripheral blood cells taken from 32 of these individuals between 1991-92 were used for preparation of DNA. This material was then subjected to polymerase chain reaction to amplify proviral XMRV DNA. The primer sets used were the same as those employed in... virology blog blogs http://www.medworm.com/rss/comments.php?id=3311288 Fri, 26 Feb 2010 04:02:36 +0100 3311288 http://www.medworm.com/index.php?rid=3301987&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F009_W3310_10.mp4 Download: .wmv (352 MB) | .mp4 (74 MB) Presented by guest lecturer Saul Silverstein, Ph.D. Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3301987 Tue, 23 Feb 2010 22:00:26 +0100 3301987 http://www.medworm.com/index.php?rid=3301988&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F008_W3310_10.mp4 Download: .wmv (298 MB) | .mp4 (65 MB) My apologies for the poor audio in this lecture: I neglected to turn on my lapel mic and the entire session was recorded on the microphone in my laptop – which was across the room. Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3301988 Tue, 23 Feb 2010 21:58:11 +0100 3301988 http://www.medworm.com/index.php?rid=3298277&cid=t_108260_87_f&fid=34872&url=http%3A%2F%2Fwww.blisstree.com%2Fhealthbolt%2Fredesign-hot-dogs-to-reduce-choking%2F I’m going to have to add a subsection to the Duh Files called the “Are you freaking serious?” file, because just when you’re sure you’ve heard everything, something else surprises you. New on the list: there’s a call to redesign hot dogs so children won’t choke on them. To be fair, a child who is choking is a horrible, frightening thing and too many children do choke. Sadly, many parents and by-standers don’t know what to do because they’ve never learned first aid techniques. But we have gotten better about passing regulations as to how small children’s toys can be, how parts can’t break off, and so on. According to a policy statement issued by the American Academy of Pediatricians, -At least one child dies from choking on ... Healthbolt blogs http://www.medworm.com/rss/comments.php?id=3298277 Tue, 23 Feb 2010 04:35:43 +0100 3298277 http://www.medworm.com/index.php?rid=3298010&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FCPi-oZmeSKk%2F Since electron micrographs first revealed the bullet-shaped morphology of vesicular stomatitis virus (a virus related to rabies virus), understanding the architecture has been elusive. It was known that the RNA genome is wrapped in a helical structure by the viral nucleocapsid (N) protein, but how this structure was encased by the viral matrix (M) protein and the envelope was not clear. These questions have been elegantly answered by a new model of the VSV virion determined by cryo-electron microscopy. The RNA genome of VSV is coated with many copies of the N protein to form a nucleocapsid with helical symmetry. The nucleocapsid is in turn surrounded by the M protein and then the viral membrane. The reconstructed image (right) not only shows the helical nature of the N protein – RNA... virology blog blogs http://www.medworm.com/rss/comments.php?id=3298010 Tue, 23 Feb 2010 04:00:43 +0100 3298010 http://www.medworm.com/index.php?rid=3287419&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FKsK0AgKil_M%2F Broad spectrum antibiotics are available that act against a wide range of bacteria, including both gram-positive and gram-negative species. In contrast, our antiviral arsenal is exceedingly specific. Nearly all the known antivirals block infection with one or two different viruses. The discovery of a compound that blocks infection with many different enveloped viruses may change the landscape of antiviral therapy. A small molecule has been discovered that inhibits infection by a wide range of viruses with membranes, the so-called enveloped viruses. The compound, called LJ001, is a derivative of aryl methylene rhodanine. It was discovered in a search for compounds that block the entry of Nipah virus into cells. LJ001 was then found to block infection of cells by a wide variety of enveloped ... virology blog blogs http://www.medworm.com/rss/comments.php?id=3287419 Thu, 18 Feb 2010 22:59:23 +0100 3287419 http://www.medworm.com/index.php?rid=3287420&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F007_W3310_10.wmv Download: .wmv (354 MB) | .mp4 (92 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3287420 Thu, 18 Feb 2010 18:44:13 +0100 3287420 http://www.medworm.com/index.php?rid=3275540&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FXVFhebH9lYo%2F A new retrovirus, xenotropic murine leukaemia virus-related virus (XMRV), first identified in tumor tissue of individuals with prostate cancer, was subsequently found in 68 of 101 US patients with chronic fatigue syndrome (CFS). XMRV was not detected in blood samples of 186 confirmed CFS patients in the United Kingdom. A second independent study in the UK (pdf) has also failed to reveal XMRV in CFS patients. The subjects of this study were confirmed CFS patients from St George’s University of London, Barts and the London Hospital Trust, and Glasgow Caledonian University. A total of 170 serum samples from CFS patients and 395 controls were used. A polymerase chain reaction assay was devised that could detect as little as 16 copies of proviral XMRV DNA (viral DNA integrated into human chro... virology blog blogs http://www.medworm.com/rss/comments.php?id=3275540 Mon, 15 Feb 2010 20:07:08 +0100 3275540 http://www.medworm.com/index.php?rid=3266701&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FNzr5kGw2Wnw%2F Influenza A viruses typically cause severe respiratory disease mainly in the very young or the elderly. The 2009 swine-origin H1N1 virus is unusual because it preferentially infects individuals under 35 years of age. We’ve previously noted that being older is a good defense against 2009 H1N1 influenza virus, in part because older people have antibodies that block infection. Experiments done in mice show that immunization with 1918-like or classical H1N1 swine influenza viruses protects against infection with 2009 H1N1 virus. When mice are inoculated intranasally with a high dose of the 2009 H1N1 influenza virus, the virus replicates in the lungs and leads to significant weight loss and lethality. After a sublethal virus dose the mice develop protective antibodies that protect agains... virology blog blogs http://www.medworm.com/rss/comments.php?id=3266701 Thu, 11 Feb 2010 20:17:26 +0100 3266701 http://www.medworm.com/index.php?rid=3254136&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F006_W3310_10.wmv Download: .wmv (324 MB) | .mp4 (76 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3254136 Tue, 09 Feb 2010 16:19:46 +0100 3254136 http://www.medworm.com/index.php?rid=3243352&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F005_W3310_10.mp4 Download: .wmv (386 MB) | .mp4 (131 MB) There are some errors in this lecture – I’ll correct them during the next session. Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3243352 Fri, 05 Feb 2010 12:00:41 +0100 3243352 http://www.medworm.com/index.php?rid=3235515&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FeVxKn1VOhbM%2F One of the most important procedures in virology is measuring the virus titer – the concentration of viruses in a sample. A widely used approach for determining the quantity of infectious virus is the plaque assay. In this technique, the spread of progeny viruses released by individually infected cells is restricted to neighboring cells by a semisolid medium. Consequently, each infectious particle produces a circular zone of infected cells called a plaque. By imagining live, virus-infected cells using a microscope, beautiful movies have been made which show how a plaque develops in real time. To produce the movies, cells were infected with vaccinia virus, covered with a semi-solid medium, and placed in an incubator. The monolayers were examined periodically until a small plaque became vi... virology blog blogs http://www.medworm.com/rss/comments.php?id=3235515 Wed, 03 Feb 2010 11:59:48 +0100 3235515 http://www.medworm.com/index.php?rid=3235516&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F004_W3310_10.wmv Download: .wmv (394 MB) | .mp4 (110 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3235516 Tue, 02 Feb 2010 23:19:36 +0100 3235516 http://www.medworm.com/index.php?rid=3223022&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F003_W3310_10.mp4 Download: .wmv (333 MB) | .mp4 (75 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3223022 Fri, 29 Jan 2010 22:00:18 +0100 3223022 http://www.medworm.com/index.php?rid=3208079&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F002_W3310_10.mp4 Download: .wmv (348 MB) | .mp4 (116 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3208079 Tue, 26 Jan 2010 12:08:12 +0100 3208079 http://www.medworm.com/index.php?rid=3197378&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F80sk93Gcwow%2F For thousands of years, epidemics of contagious diseases were believed to be caused by the wrath of the gods, configuration of stars, or miasma. The association of specific microorganisms with disease came about as a consequence of the work of the German physician Robert Koch. He formulated a set of criteria that could be used to identify the pathogen responsible for a specific disease. These criteria came to be known as Koch’s postulates: The organism must be regularly associated with the disease and its characteristic lesions. The organism must be isolated from the diseased host and grown in culture. The disease must be reproduced when a pure culture of the organism is introduced into a healthy, susceptible host. The same organism must be reisolated from the experimentally infecte... virology blog blogs http://www.medworm.com/rss/comments.php?id=3197378 Fri, 22 Jan 2010 13:00:41 +0100 3197378 http://www.medworm.com/index.php?rid=3197379&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2F001_W3310_10.mp4 Larger versions: .wmv (612 MB) | .mp4 (87 MB) Visit the virology W3310 home page for a complete list of course resources. (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3197379 Thu, 21 Jan 2010 22:04:24 +0100 3197379 http://www.medworm.com/index.php?rid=3188876&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FyEjW4dYWK8I%2F Tomorrow is the start of my new virology course at Columbia University. The course, Biology W3310, is aimed at advanced undergraduates and will be taught at the Morningside Campus of Columbia University. Columbia University encompasses two principal campuses: the historic, neoclassical campus in the Morningside Heights neighborhood and the modern Medical Center further uptown, in Washington Heights. The two are separated by fifty-two city blocks, a distance of over two miles and 20-30 minutes by subway. My laboratory is at the Medical Center, where I’ve taught a variety of virology courses over the years. However, a virology course has not been offered at the Morningside Heights campus since the late 1980s. This is a serious omission for a first-class University. Sending graduates in... virology blog blogs http://www.medworm.com/rss/comments.php?id=3188876 Tue, 19 Jan 2010 17:52:08 +0100 3188876 http://www.medworm.com/index.php?rid=3166775&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F7ABuOXRMEo4%2F The chromosomal DNA of several mammals has been found to contain sequences related to the nucleoprotein (N) gene of bornaviruses, enveloped viruses with a negative-strand RNA genome. I am amazed by this finding. How did bornaviral DNA get in our chromosomes, and what is it doing there? A search of the human genome sequence revealed DNA copies of the bornaviral N protein gene. This 370 amino acid viral protein is wrapped around the viral RNA, where it functions during RNA synthesis. Four different insertions of N protein DNA were found, all encoding proteins that are shorter than the viral counterpart.  DNA encoding bornaviral N protein was also found in the genomes of the chimpanzee, gorilla, orangutan, rhesus macaque, lemur, Garnett’s galago, African elephant, Cape hyrax, rat, mou... virology blog blogs http://www.medworm.com/rss/comments.php?id=3166775 Wed, 13 Jan 2010 15:22:03 +0100 3166775 http://www.medworm.com/index.php?rid=3126477&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F9F6kjjjpdzY%2F In healthy individuals, the first encounter with a virus leads to a primary antibody response. When an infection occurs with the same or a similar virus, a rapid antibody response occurs that is called the secondary antibody response. Antibodies are critical for preventing many viral infections, including influenza. But reinfection may occur if we encounter the same virus before the primary response is complete. Recently three cases of confirmed infection with 2009 influenza H1N1 were reported in Chile. The first patient had laboratory confirmed infection; treatment with oseltamivir resolved symptoms after 48 hours. Twenty days later the patient developed a second bout of laboratory confirmed influenza which was treated with amantadine. The second patient acquired laboratory confirmed i... virology blog blogs http://www.medworm.com/rss/comments.php?id=3126477 Mon, 28 Dec 2009 21:09:44 +0100 3126477 http://www.medworm.com/index.php?rid=3118627&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F-I4k-Kd0LyQ%2F In the wake of a British Medical Journal article which concludes that Tamiflu has at best a modest effect, many readers have asked if influenza neuraminidase inhibitors function at all. If you’d like a good critique of this study, I suggest reading Paul Revere’s analysis of the at Effect Measure. For our part, we’ll examine some of the virological evidence for the effectiveness of Tamiflu. One of the first human studies on the effectiveness of Tamiflu was published about ten years ago. The human subjects (117 healthy adult volunteers, 18-40 years of age, with hemagglutination-inhibition antibody titers 1:8 or lower) were infected intranasally with a seasonal H1N1 strain of influenza virus. Some subjects were given Tamiflu or placebo 26 hours before infection, while others... virology blog blogs http://www.medworm.com/rss/comments.php?id=3118627 Wed, 23 Dec 2009 20:40:12 +0100 3118627 http://www.medworm.com/index.php?rid=3078960&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FjEBJUSa75y0%2F Before the development of cell culture, many viruses were propagated in embryonated chicken eggs. Today this method is most commonly used for growth of influenza virus. The excellent yield of virus from chicken eggs has led to their widespread use in research laboratories and for vaccine production. In fact the vast majority of influenza vaccines – both inactivated and infectious – are produced in chicken eggs. How is influenza virus propagated in eggs? The illustration below shows a cutaway view of an embryonated chicken egg. The different routes of inoculation into the egg are shown, as well as the different compartments in which viruses replicate. For propagation of influenza virus, pathogen-free eggs are used 11-12 days after fertilization. The egg is placed in front of a ... virology blog blogs http://www.medworm.com/rss/comments.php?id=3078960 Thu, 10 Dec 2009 20:51:51 +0100 3078960 http://www.medworm.com/index.php?rid=3066735&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FfVPd2Mu0nD4%2F Xenotropic murine leukemia virus related virus (XMRV) has been implicated in prostate cancer and chronic fatigue syndrome (CFS). Because XMRV is a retrovirus, it has been suggested that it might be susceptible to some of the many drugs available for treatment of AIDS. Of ten licensed compounds evaluated for activity against XMRV, just one, AZT (azidothymidine), was found to inhibit viral replication. Compounds used to treat HIV-1 infection fall into distinct classes: protease inhibitors (Ritonavir, Saquinavir, or Indinavir), nucleoside reverse transcriptase inhibitors (NRTI, AZT, 3TC, Tnofovir, D4T), non-nucleoside reverse transcriptase inhibitors (NNRTI, Efavirenz, Nevirapine), integrase inhibitors (118-D-24), and fusion inhibitors (Maraviroc). None of the HIV-1 protease inhibitors, NNRTI... virology blog blogs http://www.medworm.com/rss/comments.php?id=3066735 Tue, 08 Dec 2009 11:00:33 +0100 3066735 http://www.medworm.com/index.php?rid=3056284&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Fwww.virology.ws%2FCUvaccines2009.mov Today I lectured on viral vaccines in the Immunology course at the Morningside Heights campus of Columbia University. I used poliovirus and influenza virus vaccines to illustrate general principles of immunization. My thanks to the engaged students who asked excellent questions! Here is a video of my lecture. Thanks to ScreenFlow, I was able to record my audio along with the slides and post it here the same day. Next semester I’ll be teaching a new undergraduate virology course at Columbia University, and I plan to upload similar videos of each lecture – 26 in all. I’ll post more information here about that course in early 2010. Download ‘Vaccines’ video. 67 MB .mov video file 247 MB .wmv video file (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3056284 Wed, 02 Dec 2009 23:18:04 +0100 3056284 http://www.medworm.com/index.php?rid=3029499&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FlIcG99yrLTc%2F Each year I teach basic virology to medical, dental, and nursing students here at Columbia University Medical Center. Here are videocasts of my three lectures for 2009: Introduction to Virology I and II, and Viral Pathogenesis. Introduction to Virology Part I Download Introduction to Virology Part I (15 MB) Introduction to Virology Part II Get the Flash Player to see this video. // Download Introduction to Virology Part II (34 MB) Viral Pathogenesis Get the Flash Player to see this video. // Download Viral Pathogenesis (16 MB) (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3029499 Thu, 26 Nov 2009 11:00:18 +0100 3029499 http://www.medworm.com/index.php?rid=3022728&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FR2_2kJHRwx0%2F The Norwegian Institute of Public Health recently identified a mutation in 2009 H1N1 influenza virus isolated from two patients who died and one with severe disease. It has been suggested that this mutation, which causes a change from the amino acid aspartic acid to glycine at position 225 of the viral HA protein (D225G), could make the virus more likely to infect deeper in the airways and cause more severe disease. What is the basis for this concern and does it have merit? Attachment of all influenza A virus strains to cells requires sialic acids. There are a number of chemically different forms of sialic acids, and influenza virus strains vary in their affinity for them. Human influenza A strains bind preferentially to sialic acids linked to galactose by an alpha(2,6) bond, while avian a... virology blog blogs http://www.medworm.com/rss/comments.php?id=3022728 Tue, 24 Nov 2009 16:57:49 +0100 3022728 http://www.medworm.com/index.php?rid=3022729&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F1LdQplUyGXQ%2F Recently I began experiments to understand how zinc inhibits rhinovirus replication, and I promised to document my findings on the pages of this blog. Here are the results of the second plaque assay. In the last experiment I confirmed the finding that 0.1 mM ZnCl2 inhibits plaque formation by rhinovirus type 1A. Based on the results of that plaque assay, shown in the figure at left, I’ve decided that this concentration of zinc isn’t sufficient to completely inhibit viral replication. Although 0.1 mM ZnCl2 blocked plaque formation when 20 or 200 pfu were inoculated on cells, many plaques arose on plates inoculated with 2000 pfu. These cannot be viral mutants resistant to zinc – there are too many of them. If there are 2000 plaques on the untreated plate, and 200 on the pla... virology blog blogs http://www.medworm.com/rss/comments.php?id=3022729 Mon, 23 Nov 2009 17:27:58 +0100 3022729 http://www.medworm.com/index.php?rid=3016917&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FngiTUDQgfpU%2F The finding that a retrovirus, XMRV, is associated with chronic fatigue syndrome has lead to the suggestion that the disease might be treated with some of the antiviral drugs used to treat AIDS. The integrase inhibitor Raltegravir has been found to block the replication of murine leukemia virus, which is highly related to XMRV. But the drug exacerbates autoimmune disease in mice which might rule out its use in treating CFS. Retroviruses such as XMVR and HIV-1 have genomes composed of single-stranded RNA. This nucleic acid is converted to a DNA copy in infected cells by the viral enzyme reverse transcriptase. The double-stranded viral DNA is then integrated into the chromosomal DNA of the host cell, a process accomplished by an viral enzyme called integrase (illustrated). Raltegravir (pict... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016917 Fri, 20 Nov 2009 15:37:00 +0100 3016917 http://www.medworm.com/index.php?rid=3016921&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FuT27EUkmad4%2F The emergence of oseltamivir (Tamiflu)-resistant 2009 H1N1 influenza virus in a Canadian family illustrates the basic concept that viral loads depend on the dose of antiviral drug. Neuraminidase inhibitors like Tamiflu and Relenza are used to treat severe illness caused by the 2009 pandemic influenza A (H1N1) virus. The antiviral drugs may also be used to prevent infection in high-risk persons, a use called postexposure prophylaxis. For Tamiflu, that means taking 75 mg a day, compared with the same dose twice a day for treating a confirmed infection. Unfortunately, using sub-optimal levels of an antiviral drug is a recipe for disaster. In this case, a boy with asthma developed confirmed H1N1 influenza and was given Tamiflu twice a day. Tamiflu was also prescribed once a day for all members... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016921 Tue, 17 Nov 2009 11:00:37 +0100 3016921 http://www.medworm.com/index.php?rid=3016925&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F6lLEi6_Ck78%2F This study was carried out – where else? – in Switzerland, where 7 million individuals exchange 20 – 100 million banknotes each day. Thomas Y, Vogel G, Wunderli W, Suter P, Witschi M, Koch D, Tapparel C, & Kaiser L (2008). Survival of influenza virus on banknotes. Applied and environmental microbiology, 74 (10), 3002-7 PMID: 18359825 (Source: virology blog) virology blog blogs http://www.medworm.com/rss/comments.php?id=3016925 Tue, 10 Nov 2009 18:13:28 +0100 3016925 http://www.medworm.com/index.php?rid=3016926&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FqQsjBjTd9LQ%2F The suggestion that yearly immunization against influenza might make children more susceptible to serious disease during a pandemic has generated some controversy. Does this idea have merit? If you have read “Being older is a good defense against 2009 H1N1 influenza”, you are familiar with the concept of ‘heterosubtypic immunity’. After natural infection with influenza virus, the host produces T and B cells directed against internal proteins of the virions. These viral proteins are more conserved among different strains than the surface glycoproteins HA and NA. Upon infection with a different subtype – which occurs during a pandemic – heterosubtypic immunity could limit virus replication and reduce disease and death. Evidence for heterosubtypic immunity to influenza vir... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016926 Fri, 06 Nov 2009 13:00:22 +0100 3016926 http://www.medworm.com/index.php?rid=3016927&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F5meqJhkqthM%2F The title of this post should not come as a surprise to readers of virology blog – it was shown in 1974 that zinc could interfere with replication of rhinoviruses (see “Zinc and the common cold“). I am referring to the result of my first experiment to study the mechanism of zinc inhibition – something I promised I would document on these pages. I am interested in understanding how zinc inhibits rhinovirus replication. Answering this question could lead to new ways to prevent common colds caused by these viruses. The first step was to reproduce the effect of zinc in my laboratory with my stocks of rhinovirus. I selected rhinovirus type 1a for my initial experiments because we’ve worked with this serotype in the past: we know the genome sequence and how the viru... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016927 Wed, 04 Nov 2009 15:35:42 +0100 3016927 http://www.medworm.com/index.php?rid=3016937&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FNkSPP3aIOwQ%2F A retrovirus that has been implicated in prostate cancer has now been found in the blood of patients with chronic fatigue syndrome. What is this virus and where did it come from? Chronic fatigue syndrome (CFS) is a disease characterized by fatigue and chronic inflammation that can last years and may affect ~1% of the world’s population. The etiology of the disease is unknown, although several viruses have been suggested to be involved, including enteroviruses and herpesviruses. The retrovirus XMRV (xenotropic Moloney murine leukemia virus-related virus) was recently identified in the tumor tissue of individuals with prostate cancer. XMRV nucleic acid was detected by polymerase chain reaction in the blood of 68 out of 101 samples (67%) from CFS patients. The virus was also found in 8 ... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016937 Thu, 15 Oct 2009 20:11:56 +0100 3016937 http://www.medworm.com/index.php?rid=2886206&cid=t_108260_77_f&fid=37259&url=http%3A%2F%2Fwww.horizonpress.com%2Fblogger%2F2009%2F10%2F1918-pandemic-influenza-virus.html The pandemic influenza virus of 1918 was extremely virulent and caused significant morbidity and mortality to millions of people worldwide. The extinct virus caused severe pathology in both the upper and lower respiratory tract, resulting in fatal respiratory complications and bacterial pneumonia. The pathology associated with 1918 influenza virus infections is thought to be the result of the exposure of an immunologically naive host population to an unusually virulent virus. Using reverse genetics, the 1918 pandemic virus has been studied in an attempt to determine which viral genes contribute to the increased virulence. Studies to date point to the role of the hemagglutinin, neuraminidase, and the polymerase basic protein 1 genes as the virulence genes responsible for the high pathogenic... Microbiology Blog: The weblog for microbiologists. blogs http://www.medworm.com/rss/comments.php?id=2886206 Mon, 12 Oct 2009 15:46:00 +0100 2886206 http://www.medworm.com/index.php?rid=3016939&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F0MFyMM52X9E%2F The new director of the National Institutes of Health, Francis Collins, has been scrutinized for his Evangelical Christian beliefs, which some think might influence his science policy. But there may be an even more serious problem with his leadership of the biggest supporter of scientific research in the United States. A recent New York Times article focused on Collins’ religious beliefs. The following statement, which was buried in the article, worries me much more: While acknowledging the importance of basic sciences like biochemistry and genetics, he said he wanted scientists to consider clinical or therapeutic implications in their work. “We’re not the National Institutes of Basic Sciences,” he said. “We’re the National Institutes of Health.” Since its inception, the... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016939 Fri, 09 Oct 2009 13:00:49 +0100 3016939 http://www.medworm.com/index.php?rid=3016940&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FD5Mqho7bBCs%2F Shortly after I developed sore throat, cough, and congestion last week, a package of ‘Cold – Eeze’ materialized on my kitchen counter. The writing on the package of zinc-laden lozenges promised to ’shorten your cold’, and noted that they were ‘clinically proven to reduce the duration of the common cold’. Do zinc lozenges have any effect on the common cold? The common cold is the primary cause of doctor visits in the United States, leading to 189 million lost school days each year. But it’s important to point out that the common cold can be caused by a number of different viruses, including rhinovirus, coronavirus, influenza virus, adenovirus, and paramyxovirus. Rhinoviruses are responsible for over half of all common colds. The idea that zinc... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016940 Thu, 08 Oct 2009 14:58:46 +0100 3016940 http://www.medworm.com/index.php?rid=3016941&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FAAd62pyT5Ec%2F Antibodies produced by infection with a virus, or after immunization with viral vaccines, are effective at preventing viral disease. However humans and higher primates contains “natural antibodies” which are present in serum before viral infection. Natural antibodies can activate the classical complement pathway leading to lysis of enveloped virus particles long before the adaptive immune response is activated. Many natural antibodies are directed against the disaccharide galactose α(1,3)-galactose (α-Gal) (illustration), which is found as a terminal sugar on glycosylated cell surface proteins. Humans, apes, and Old World monkeys lack the gene encoding the enzyme galactosyltransferase, which attaches α-Gal to membrane proteins. Lower primates, most other animals, and bact... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016941 Tue, 06 Oct 2009 17:37:01 +0100 3016941 http://www.medworm.com/index.php?rid=3016943&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FLCpPTwJRsoY%2F The classical complement pathway begins when the initiator protein C1q binds directly to the surface of a pathogen, or to an antibody that is bound to a microbe. There is a binding site for C1q on the Fc portion of antibody molecules. C1q can also recognize molecular patterns characteristic of pathogens, much like the Toll-like receptors. C1q binding to antibody or a pathogen surface initiates an unusual protease cascade with one or more members of a set of seven activating enzymes. This set of cleavages, which occurs on the surface of the microbe, leads to the formation of the membrane attack complex that produces holes in membranes of cells and viruses. Other products of the cascade include mediators of inflammation, which recruit white blood cells to the site of infection. Still mor... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016943 Fri, 02 Oct 2009 02:37:04 +0100 3016943 http://www.medworm.com/index.php?rid=3016945&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FDY9BKhA9ABU%2F is a collection of blood and cell surface proteins that is a major primary defense and a clearance component of innate and adaptive immune responses. At least 30 different complement proteins act sequentially to produce a wide ranges of activities, from cell lysis to augmentation of the adaptive response. The complement system has four major antimicrobial functions. Lysis – Polymerization of specific activated complement components on a foreign cell or enveloped virus leads to the formation of pores. The lipid bilayer of the cell or virus is disrupted. Activation of inflammation – Several peptides produced by proteolytic cleavage of complement proteins bind to vascular endothelial cells and lymphocytes. These cells then produce cytokines which stimulate inflammation and enhan... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016945 Mon, 28 Sep 2009 21:18:04 +0100 3016945 http://www.medworm.com/index.php?rid=2832338&cid=t_108260_131_f&fid=34989&url=http%3A%2F%2Ffeeds.b5media.com%2F%7Er%2Fb5media%2FGeneticsHealth%2F%7E3%2F9r0qn2IL2dM%2F For many of us, GENETICS is a intimidating topic. Don’t worry, I feel the same way around technology and computer language. When we start reading sentences where half the words are foreign, then it can seem way over our heads. And I think people have an idea that genetics is important to medicine and health care, but what role it plays (and how genes act) might be where the questions are. So that’s why I’m adding a regular feature to explain the basics and call it “What we need to know to get genetics” or something like that. Obviously, this won’t be the “complete course in Genetics 101” or “Genetics for Dummies” (there’s a already a Genetics For Dummies (For Dummies (Math & Science))’ target=_blank>book on that) but hopefully the outlines below would be... Genetics and Health blogs http://www.medworm.com/rss/comments.php?id=2832338 Fri, 25 Sep 2009 04:39:47 +0100 2832338 http://www.medworm.com/index.php?rid=3016946&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FhY74WafjJTI%2F Influenza A viruses tend to garner most of the attention, but let’s not forget that there are two other virus types, B and C. The enveloped influenza A virions have three membrane proteins (HA, NA, M2), a matrix protein (M1) just below the lipid bilayer, a ribonucleoprotein core (consisting of 8 viral RNA segments and three proteins: PA, PB1, PB2), and the NEP/NS2 protein. It would be difficult to distinguish influenza A and B viruses by electron microscopy, but there are differences. Influenza B virions have four proteins in the envelope: HA, NA, NB, and BM2. Like the M2 protein of influenza A virus, the BM2 protein is a proton channel that is essential for the uncoating process. The NB protein is believed to be an ion channel, but it is not required for viral replication in cell cu... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016946 Tue, 22 Sep 2009 18:04:28 +0100 3016946 http://www.medworm.com/index.php?rid=3016947&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2FB_kwBKpERVk%2F During a discussion about blogging on the Coast to Coast Bio Podcast, it was suggested that science professors should spend more time writing about their research – by explaining what problems they are trying to solve, how they approach them, and why they are interesting. My goal here at virology blog is mainly to teach virology. But explaining what we do in my virology laboratory can be an effective instructional tool. About five years ago I became very interested in the innate immune response to viral infections. The innate response is considered the first line of immune defense because it is active even before infection begins. Many viral infections are halted by the innate immune system, which responds very quickly – within minutes to hours after infection. The key to innate de... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016947 Fri, 18 Sep 2009 12:00:56 +0100 3016947 http://www.medworm.com/index.php?rid=3016948&cid=t_108260_139_f&fid=38879&url=http%3A%2F%2Ffeedproxy.google.com%2F%7Er%2FVirologyBlog%2F%7E3%2F2seSIAybp2o%2F Would influenza virus be the same pathogen if it could not undergo reassortment of its segmented RNA genome? This is the question being asked in the wake of the development of a method to prevent the free assortment of influenza viral RNAs. The process of influenza virus replication includes the incorporation of eight viral RNAs into each newly synthesized virion. This process, called packaging, depends upon specific RNA sequences in each genome segment. By swapping the packaging sequences for the nonstructural protein (NS) and HA genes, a virus was produced which replicated but lost the ability to independently reassort the HA or NS gene. The authors note that the other influenza A virus RNA segments could be modified in a similar way to reduce or eliminate their ability to form reassorta... virology blog blogs http://www.medworm.com/rss/comments.php?id=3016948 Tue, 15 Sep 2009 12:00:10 +0100 3016948