Near the end of the podcast when Rich Condit was talking about the voyages of James Cook I wondered if he had read the book by Richard Holmes, “The Age of Wonder.” Any book by Richard Holmes is a treat but this one is special for those who love science, since it details an age in which science was a fascination of just about everyone in the world. The book begins with “Joseph Banks in Paradise.” Banks was the official botanist to HM Bark Endeavour, commanded by Lieutenant James Cook. It goes on to cover many more topics, all of which are fascinating.
Hello dear TWiV hosts!
Traditionally – “long time listener, second time writer”. Few notes about the conversation in latest TWiV.
- Trigeminal nerve is CN V (fifth cranial nerve). It cannot be thirteen as Dr. Despommier vaguely suggested – there are only 12 cranial nerves.
- Ganglion (plural – ganglia) is the accumulation of neuronal bodies rather than nerves (in reference to Dr. Condit’s comment). These bundles of neuronal bodies are called ganglia in the peripheral nervous system, and they are nuclei in the CNS. For example, dorsal horn ganglion can be found in the dorsal root of a spinal nerve.
- Prevalence of HSV-1 infection increases with age, as Dr. Condit noted. To corroborate this notion, I attach links to two papers with the serological survey data obtained in Slovenia and China. These data also suggest that HSV-1 seroprevalence is much higher than that of HSV-2.
Thank you for your service to science. Driving around Cleveland is much less stressful with your podcast in the car audio system.
Mikhail “Mike” Khoretonenko, PhD
Department of Biology
Lakeland Community College
Ruan and Michelle write:
HSV-1’s apparent association with Alzheimer’s disease has been the hot topic in our lab the last few weeks and we thoroughly enjoyed the episode addressing it. We would like to add a few thoughts from our perspective in clinical virology.
The suggestion that lytic viral replication is the aetiology, seems, at least anecdotally, doubtful. The detection of HSV DNA in CSF (cerebrospinal fluid) is exceedingly sensitive and specific for HSV encephalitis, such that when detecting it, we can generally provide the diagnosis with some confidence. For context, a diagnosis exclusively from a lab test is uncommon but the “correlate clinically” proviso that goes out with all our reports should really be replaced with a bag of acyclovir when it comes to a positive HSV CSF PCR. HSV encephalitis is also not a mild illness which may be dismissed, it comes with a high mortality and invariable neurological sequelae for survivors. So significant lytic replication, we doubt.
The data showing HSV’s Alzheimers association is there, however, and needs to be understood. On the one side, focal contained areas of replication can certainly not be excluded with ease, but one has to question which way the train is going, as the Twiv team mentioned. One perspective might be the creation of focal zones permissive to HSV replication, possibly through innate immune dysregulation secondary to Alzheimers pathology. This, particularly, is an attractive thought considering the association of HSV encephalitis with defects in TLR3 signalling shown by Zhang et al. in 2007, with subsequent further investigation by other labs.
Further, an explanation for the data regarding the negative association between Alzheimers and acyclovir use is also interesting. One might be tempted to think that it could be explained by activation of the HSV thymidine kinase gene in stressed neurons without progression to lytic replication. This may result in targeted genotoxic effects resulting in apoptosis from administered acyclovir in stressed cells, which may have acted as paracrine immune dysregulators driving pathology. This principle has already been extensively explored in cancer gene therapy, with cancer cells being transduced with a thymidine kinase gene and ganciclovir subsequently being administered to kill the cancer cells. Acyclovir triphosphate (post thymidine kinase and cellular kinase activity) does favour viral polymerase, but if not all viral genes are expressed (polymerase gene), cellular polymerase may incorporate it with greater frequency.
These ideas may, of course, be totally wrong but we think a lot of investigation will need to happen and many people will need to be wrong before we understand the true nature of the apparent HSV/Alzheimers association.
PS Cape Town is a great place to come do a Twiv episode, especially on HIV vaccinology
Ruan and Michelle
Residents in Clinical Virology, University of Cape Town
Here in Northern California the weather is sunny with clear blue skies and a temperature in the mid-to-high seventies, or about 24-25 for those who measure in Celsius. In other words, classic, beautiful, California Autumn weather.
Last Sunday I went to the local firehouse for a FREE flu shot. My nomination for listener pick is a page on the CDC’s website. This page — https://www.cdc.gov/flu/weekly/usmap.htm — features an animation showing spread of flu cases throughout the United States plus D.C., Guam, Puerto Rico, and US Virgin Islands as the flu season progresses. It has a small database allowing you to see flu progression by season going back to 2003. Clearly some years are way worse than others.
ON TWiV it has been noted that flu transmits more effectively in colder weather. Questions: is there an optimal temperature range for flu transmission? Have any studies explored the probability of transmission based on temperature?
Worst in Texas so far…
A review about environmental factors: https://www.ncbi.nlm.nih.gov/pubmed/?term=25422855
“Seasonality of influenza is largely dictated by temperature and humidity, with cool-dry conditions enhancing IAV survival and transmissibility in temperate climates in high latitudes, whereas humid-rainy conditions favor outbreaks in low latitudes, as seen in tropical and subtropical zones. In mid-latitudes, semiannual outbreaks result from alternating cool-dry and humid-rainy conditions. The mechanism of virus survival in the cool-dry or humid-rainy conditions is largely determined by the presence of salts and proteins in the respiratory droplets. “
I got my flu shot. Did you?
I noticed on Twiv 516 that Jeremy Luban took special care to credit each lab that came up with an advance by name. This may happen in every TWIV, but this is the first time I’ve noticed that. It’s so important to give labs – even your competitors, ESPECIALLY your competitors – credit for their work. Competition and collegiality are not mutually exclusive, and it’s important to remember we all want the same thing. I hope every guest is as diligent as Dr. Luban was in giving credit where credit is due.
The gd weather!
Please edit the beginning of the podcast to reduce the casted small talk to under 30s. I hate to be so blunt, but in episode 517 I skipped in to 6:18 before I started listening. The content is very interesting and provides a great public service, but all of this could be lost if your listener base drives into a bridge abutment while trying to skip the off topic forward. The number, 30s, is inspired by other podcasts with ads. Ads over 30s I skip over. This comment applies to all of the twiXX podcasts.
Again I really appreciate the information and discussion. I am an aerospace engineer and it is not easy for me to access biological research or spend the time to understand it. Thank you!
I’ve been subscribed and listening for years. This the first feedback I felt I wanted to weigh in with. I wholeheartedly support you all inviting Jens back as you seemed to intend. I loved the episode (508).
You all have great chemistry and he complimented it well, in addition to being very interesting and evoking a lot of laughter from me.
In Sedona, AZ it is sunny, clear, and a comfy 72F. In addition we felt a small earthquake yesterday which was the last one reported in 2 years!
Hi all – from a beautiful ‘dreich’ morning in Scotland…
Last year I sent in information showcasing the virology colouring book that we at the MRC-University of Glasgow Centre for Virus Research produced as part of that year’s MRC ‘Festival of Medical Research’.
This year we have helped produce another tool to help engage people with the world of viruses and we thought that you and your listeners would like to hear about it.
This time we (which is Ed Hutchinson, an MRC fellow here, and I, Connor Bamford) teamed up with the acclaimed Glasgow School of Art and an extremely talented Master’s student, Rachael Suétt to make a free, augmented reality app for your Android phone (sorry Apple supporters!).
In the app – and accompanying poster set – you can explore the structures of three important viruses: herpes simplex viruses, influenza A viruses and Zika virus. There is even a quiz to test the knowledge you have hopefully gained.
You can find more info over at our CVR blog: https://cvrblog.myportfolio.com/visible-viruses-ar-app?fbclid=IwAR2KKgX5i3fVeKOp7RHyuZZ_q_wX1eO2HNK-xyBIbyqAshVT1t8sd8SY7CY . I include specifics to download the app at the bottom of this message.
So please have a look, download the app and play; then let us know what you think!
All the best – keep up the excellent work,
Connor & Ed.
The app and posters can be downloaded from https://drive.google.com/drive/folders/1EYCY7RAhi10BdQ-dtyDjK159NyBN_e9S?usp=sharing
These educational materials are freely available under a creative commons license (CC-BY-NC-ND 4.0). The app should run on any Android phone or tablet with OS 5.0 (Lollipop) or later, though you may need to adjust your settings to allow content from unknown sources (this can be reverted after installing the app if you wish). This app is being developed as part of a student project and is still undergoing testing; it should run without issue on suitable devices but it is supplied as is and we cannot be held liable for any issues arising from its use.
We’re keen to make the app as useful as possible and if you use it we’d be really grateful if you can complete a quick survey. It should take less than 5 minutes, and as an incentive, 5 responses will be drawn at random to win an MRC goodie pack including a hard copy of our colouring book Art Goes Viral and a set of colouring pencils. Please complete the survey here:https://goo.gl/forms/f1u2I6mlRfEHWlG52