Diseases don’t always behave exactly as we expect them too. Sometimes, even when we think we’ve worked out most things about them, they can surprise us. A case study published in Dermatology Online Journal – Orf parapoxvirus infection from a cat scratch by J Frandsen et al (see below for full ref) – is a nice [...]... Read more »
Last month, a group of researchers led by Marcel Kamp in Düsseldorf. Germany, rose to fame by studying traumatic brain injury brought about by acts of violence like this:The group analyzed over 700 injuries recorded in the 34 Asterix comic books and published their results in the official journal of the European Association of Neurosurgical Societies, known as Acta Neurochirurgica. For some odd reason, I only was made aware of this groundbreaking study now. Well worth reading!Kamp, M., Slotty, P., Sarikaya-Seiwert, S., Steiger, H., & Hänggi, D. (2011). Traumatic brain injuries in illustrated literature: experience from a series of over 700 head injuries in the Asterix comic books. Acta Neurochirurgica, 153 (6), 1351-1355 DOI: 10.1007/s00701-011-0993-6... Read more »
Kamp, M., Slotty, P., Sarikaya-Seiwert, S., Steiger, H., & Hänggi, D. (2011) Traumatic brain injuries in illustrated literature: experience from a series of over 700 head injuries in the Asterix comic books. Acta Neurochirurgica, 153(6), 1351-1355. DOI: 10.1007/s00701-011-0993-6
When German botanist Friderico T. Kützing first described the microalga Botryococcus braunii in the 1849 book Species Algarum, I doubt he expected that 150 years later scientists would still be exploring its potential. It's equally probable he didn't anticipate the alga's significance for renewable energy either, which I was rather surprised to learn about myself.... Read more »
Niehaus, T.D., Okada, S., Devarenne, T.P., Watt, D.S., Sviripa, V., . (2011) Identification of unique mechanisms for triterpene biosynthesis in Botryococcus braunii. PNAS. PMID: 21746901
Schenk, P., Thomas-Hall, S., Stephens, E., Marx, U., Mussgnug, J., Posten, C., & Kruse, O., . (2008) Second generation biofuels: High-efficiency microalgae for biodiesel production. BioEnergy Research, 20-43. DOI: 10.1007/s12155-008-9008-8
Readers from this blog recognize my interest in presentation skills. Not only the presenting but also the design of slides. Often I’ve written about the boring powerpoint slides often used in lectures with endless bullet points and great deal of text. Several authors have explained why these bullet points won’t teach the audience anything. They [...]
No related posts.... Read more »
Issa, N., Schuller, M., Santacaterina, S., Shapiro, M., Wang, E., Mayer, R., & DaRosa, D. (2011) Applying multimedia design principles enhances learning in medical education. Medical Education, 45(8), 818-826. DOI: 10.1111/j.1365-2923.2011.03988.x
Ellaway, R. (2011) Reflecting on multimedia design principles in medical education. Medical Education, 45(8), 766-767. DOI: 10.1111/j.1365-2923.2011.04064.x
Description of the MECP2 gene, the protein it encodes, its role in the cell, and how various mutations affect the protein's ability to do what it needs to do in the cell, which is chiefly to bind to nucleic acids.... Read more »
Amir RE, Van den Veyver IB, Wan M, Tran CQ, Francke U, & Zoghbi HY. (1999) Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2. Nature genetics, 23(2), 185-188. PMID: 10508514
Bienvenu, T. (2000) MECP2 mutations account for most cases of typical forms of Rett syndrome. Human Molecular Genetics, 9(9), 1377-1384. DOI: 10.1093/hmg/9.9.1377
Bienvenu T, Souville I, Poirier K, Aquaviva C, Burglen L, Amiel J, Héron B, Kaminska A, Couvert P, Beldjord C.... (2001) Five novel frameshift mutations in exon 3 and 4 of the MECP2 gene identified in Rett patients: Consequences for the molecular diagnosis strategy. Human mutation, 18(3), 251-252. PMID: 11524737
Díaz de León-Guerrero, S., Pedraza-Alva, G., & Pérez-Martínez, L. (2011) In sickness and in health: the role of methyl-CpG binding protein 2 in the central nervous system. European Journal of Neuroscience, 33(9), 1563-1574. DOI: 10.1111/j.1460-9568.2011.07658.x
Free, Andrew, Robert I. D. Wakefield, Brian O. Smith, David T. F. Dryden, Paul N. Barlow, & Adrian P. Bird. (2000) DNA Recognition by the Methyl-CpG Binding Domain of MeCP2. Journal of Biological Chemistry, 276(5), 3353-3360. DOI: 10.1074/jbc.M007224200
Hoffbuhr K, Devaney JM, LaFleur B, Sirianni N, Scacheri C, Giron J, Schuette J, Innis J, Marino M, Philippart M.... (2001) MeCP2 mutations in children with and without the phenotype of Rett syndrome. Neurology, 56(11), 1486-1495. PMID: 11402105
Kudo, S., Y. Nomura, M. Segawa, N. Fujita, M. Nakao, C. Schanen, & M. Tamura. (2003) Heterogeneity in residual function of MeCP2 carrying missense mutations in the methyl CpG binding domain. Journal of Medical Genetics, 40(7), 487-493. DOI: 10.1136/jmg.40.7.487
Kumar, A., Kamboj, S., Malone, B., Kudo, S., Twiss, J., Czymmek, K., LaSalle, J., & Schanen, N. (2008) Analysis of protein domains and Rett syndrome mutations indicate that multiple regions influence chromatin-binding dynamics of the chromatin-associated protein MECP2 in vivo. Journal of Cell Science, 121(7), 1128-1137. DOI: 10.1242/jcs.016865
Raizis AM, Saleem M, MacKay R, & George PM. (2009) Spectrum of MECP2 mutations in New Zealand Rett syndrome patients. The New Zealand medical journal, 122(1296), 21-28. PMID: 19652677
Singh, J., Saxena, A., Christodoulou, J., & Ravine, D. (2008) MECP2 genomic structure and function: insights from ENCODE. Nucleic Acids Research, 36(19), 6035-6047. DOI: 10.1093/nar/gkn591
Yusufzai, Timur M., & Wolffe, Alan P. (2000) Functional consequences of Rett syndrome mutations on human MeCP2. Nucleic Acids Research, 28(21), 4172-4179. DOI: 10.1093/nar/28.21.4172
I’ll aJulia Roberts laughingdmit, the concept of laughter therapy is not new. However, I’ve been realizing lately that too few people take the potential benefits of laughter seriously. Yes, ironically, you should take laughter seriously — it’s the one contagious thing that’s nice to catch, and it’s completely free of cost. Intuitively, laughter is a good thing. But what does the research say?... Read more »
Noji S, & Takayanagi K. (2010) A case of laughter therapy that helped improve advanced gastric cancer. Japan-hospitals : the journal of the Japan Hospital Association, 59-64. PMID: 21706962
Friedler S, Glasser S, Azani L, Freedman LS, Raziel A, Strassburger D, Ron-El R, & Lerner-Geva L. (2011) The effect of medical clowning on pregnancy rates after in vitro fertilization and embryo transfer. Fertility and sterility, 95(6), 2127-30. PMID: 21211796
Berk LS, Felten DL, Tan SA, Bittman BB, & Westengard J. (2001) Modulation of neuroimmune parameters during the eustress of humor-associated mirthful laughter. Alternative therapies in health and medicine, 7(2), 62. PMID: 11253418
The infamous 'Pascal's Wager' is still often trotted out as a supposedly rational basis for believing in god. While the flaws in that one are well known, it is still commonly believed that risk-averse people are more likely to be religious. Better to go to Church than run the risk of being fried in the hereafter, the supposition goes.
Actually, evidence that risk-averse people are more religious is weaker than you might suppose. What's more, there's no reason to think that it applies in the world outside of the big three monotheisms. The gods of most Eastern religions are pretty disinterested in other worldly punishment.
In fact, Eric Liu at Baylor University has shown that risk averse Taiwanese are no more likely to be affiliated with a religion.
Intriguingly, he did find that the risk averse were more likely to participate in religious activities - and that went for Buddhism, Taoism, Chinese popular cults and Yiguan Dao (which is a modern, syncretic religion), as well as Christianity.
Liu speculates that this is because there is some risk inherent in not believing in Eastern religions. In Buddhism, failure to follow the 8-fold way means getting stuck in an endless cycle of rebirth. And Confucian and Taoist teachings promise some pretty nasty after-death punishments for those who do not follow a moral code - including those who do not pray or perform the right rituals:
Upon arrival, according to specific sentences, the sinners might be burned in flames, hunted and butchered, or boiled in oil or water. Their backs might be plowed, their tongues torn out with hot iron pincers, or their skin stripped off. They might find themselves in burning hot iron beds, have molten metal poured down their throats, or face other kinds of cruel punishment (Goodrich 1981).
So it's wrong to say that non-belief in these Eastern religions is risk-free. Yet I am not convinced that what we're seeing hear is fear of afterlife punishments.
To me it seems more likely that the risk these people are trying to avert is the very real risk present in this world, rather than potential risks in the next.
That would match with some other research showing that Europeans who believe in the afterlife actually have a lower work ethic. It seems that the religious work ethic in Europe is more to do with securing rewards in this life rather than the next.
We know that people in risky environments tend to be more religious, and I suspect that by participating in religious ceremonies these individuals are hoping that the gods will improve their fortune. What's more, we know that they can expect to get support in their hour of need from their co-religionists - and so there is a double benefit from going to religious services!
Liu, E. (2010). Are Risk-Taking Persons Less Religious? Risk Preference, Religious Affiliation, and Religious Participation in Taiwan Journal for the Scientific Study of Religion, 49 (1), 172-178 DOI: 10.1111/j.1468-5906.2009.01499.x
This article by Tom Rees was first published on Epiphenom. It is licensed under Creative Commons.
... Read more »
Liu, E. (2010) Are Risk-Taking Persons Less Religious? Risk Preference, Religious Affiliation, and Religious Participation in Taiwan. Journal for the Scientific Study of Religion, 49(1), 172-178. DOI: 10.1111/j.1468-5906.2009.01499.x
It’s easy to forget, sometimes, that when we choose an outcome measure, we need to seriously consider who will use the measures in the end. Of course, I am assuming that we’re all using outcome measures – we are, aren’t we? If anyone isn’t, shame on you – how on earth will you establish whether … Read more... Read more »
Beale, M., Cella, M., & de C. Williams, A. (2011) Comparing patients’ and clinician-researchers’ outcome choice for psychological treatment of chronic pain. PAIN. DOI: 10.1016/j.pain.2011.06.007
You’ve watched all the movies. You’ve read all the books. You’ve even practiced tactial skirmishes with lifesize zombie targets. But now, all of a sudden, you are thinking, “I didn’t know there would be math!” Actually, if you’re a regular … Continue reading →... Read more »
Philip Munz, Ioan Hudea, Joe Imad, & Robert J. Smith?. (2009) When Zombies Attack!: Mathematical Modelling of an Outbreak of Zombie Infection. Infectious Disease Modelling Research Progress, 133-150. info:/
The Google logo.Notice the logo is multi-colored (as pointed out by Neurobonkers). Seeing "Google" printed in a solid color (or in any other font, for that matter) would likely result in a Stroop effect, or a slower response time in identifying the color of the font, relative to that of a neutral word.Is Google making us stupid?That question, and its original exposition in The Atlantic, has been furthering the career of Nicholas G. Carr. His subsequent book, The Shallows: What the Internet Is Doing to Our Brains, expanded upon his broader thesis that the internet is damaging to our cognitive capacity and the way we think. Numerous writers, both pro and con, have debated whether the internet and social networking sites (and computers in general) are harmful, so I won't belabor that point here. Instead, I'll cover a new article in Science that purportedly found Google Effects on Memory (Sparrow et al., 2011).Cognitive Consequences of Having Information at Our FingertipsThe paper by Sparrow et al. (2011) conducted four experiments to determine whether the ability to access previously learned information reduces the effort put forth in remembering and retrieving the information. Specifically, the authors view the internet as a form of transactive memory, a means to offload some of the daily cognitive burden from our brains to an external source. Or, as succinctly expressed in ars technica, why bother to remember when you can just use Google?This is nothing new, nor is it something dependent on the internet. In 1985 Wegner et al. (PDF) examined the way that married couples can have a division of labor along the lines of which facts to remember (Bohannon, 2011):For example, a husband might rely on his wife to remember significant dates, while she relies on him to remember the names of distant friends and family—and this frees both from duplicating the memories in their own brains. Sparrow wondered if the Internet is filling this role for everyone, representing an enormous collective act of transactive memory. Another example is illustrated by the phenomenon of the open book test. If students know they can use their textbooks to answer questions on an exam, they may put forth less effort into rote memorization of facts, and may instead learn the organization of each chapter, familiarizing themselves with where particular facts are located within the text. That indeed is what was demonstrated in Experiments 3 and 4, but in terms of accessing the information online or from a computer's hard drive.The Google Stroop EffectExperiment 1 asked whether the participants were primed to access computer-related words when faced with difficult trivia questions, relative to when they answered easy trivia questions (examples below).Appendix A: Easy Questions1. Are dinosaurs extinct?2. Was Moby Dick written by Herman Melville?3. Is the formula for water H20?4. Is a stop sign red in color?5. Are there 24 hours in a day?. . .16. Does a triangle have 3 sides?Appendix B: Hard Questions1. Does Denmark contain more square miles than Costa Rica?2. Did Benjamin Franklin give piano lessons?3. Does an Italian deck of card contain jacks?4. Did Alfred Hitchcock eat meat?5. Are more babies conceived in February than in any other month?. . .16. Is a quince a fruit?The way the authors assessed automatic priming of internet- and computer-related words is by using a modified version of the ever-popular Stroop test. Name the font color of these words but don't read the words themselves:REDBLUEGREENNow do the same for this set of words:RED BLUE GREENBet you were faster for the first set. That's because reading is a much more automatic process than naming the ink color in which the words are printed. This conflict between response options produces interference and slows reaction times (RTs) in the task.The modified Stroop task used by Sparrow et al. relied on attentional salience rather than response conflict. Instead of color words, the participants viewed words related to computers and search engines, or words not related to these things:This color naming contained 8 target words related to computers and search engines (e.g., Google, Yahoo, screen, browser, modem, keys, internet, computer), and 16 unrelated words (e.g., Target, Nike, Coca Cola, Yoplait, table, telephone, book, hammer, nails, chair, piano, pencil, paper, eraser, laser, television).First off, you'll note that there are twice as many control words as there are computer words1. More importantly, you'll also notice that the unrelated words included prominent brand names (some of which are strongly associated with a particular color) and a grab bag of nouns from different semantic categories (furniture, tools, writing implements, musical instrument, etc.). The Google logo is multi-colored (as we've said before), and the current Yahoo logo is purple (it used to be red).Hmm. So already we're looking at quite a confound. Nonetheless, the authors expected a larger Stroop effect for the search engines for different reasons:In this case, we expect participants to have computer terms in mind, because they desire access to the information which would allow them to answer difficult questions. Participants are presented with words in either blue or red, and were asked to press a key corresponding with the correct color. At the same time, they were to hold a 6 digit number in memory, creating cognitive load.Why? Why oh why did the authors want to create a cognitive load during the Stroop? This turns the whole study into a dual task experiment, requiring the participants to multi-task: a key press for red or blue (which requires retrieval of ... Read more »
Sparrow, B., Liu, J., & Wegner, D. (2011) Google Effects on Memory: Cognitive Consequences of Having Information at Our Fingertips. Science. DOI: 10.1126/science.1207745
Consumer perception drives most of the success or failure of an industry. When consumers perceive a need for a product or service, an industry has a limitless ability to expand, innovate and thrive. In the health care industry, the product consumers crave (and need) is health and wellness. Health and wellness is an essential quality [...]... Read more »
Anderson, G., & Frogner, B. (2008) Health Spending In OECD Countries: Obtaining Value Per Dollar. Health Affairs, 27(6), 1718-1727. DOI: 10.1377/hlthaff.27.6.1718
Grossman, M. (1972) On the Concept of Health Capital and the Demand for Health. Journal of Political Economy, 80(2), 223. DOI: 10.1086/259880
Everyone knows what narcolepsy looks like from movies like the ridiculous display in Deuce Bigalow (one of the ‘adorable misfit bunch of suitors’) to other more subdued examples like Mike in My Own Private Idaho. Oh, and when I say that, I mean people know the stereotype of the instantaneous drop during dinner into a bowl of soup. What I really mean is that the stereotype isn’t the norm at all.... Read more »
Mignot E. (2001) A commentary on the neurobiology of the hypocretin/orexin system. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 25(5 Suppl). PMID: 11682267
Maret S, & Tafti M. (2005) Genetics of narcolepsy and other major sleep disorders. Swiss medical weekly, 135(45-46), 662-5. PMID: 16453205
In July and August, typically in sunny days after rains, swarms of reproductive Black Garden Ants (Lasius niger) - winged queens and males - emerge from their nest to mate and start new colonies. Workers also come out en masse and run around the entrance of the nest, looking agitated. I had often noticed this and wondered why do workers did this, until yesterday, watching a Blackbird feeding on the winged ants coming out of their nests, realised why. The Blackbird run close to the entrance, fetched a winged ant and run away. The bird repeated this several times and was obviously being stung or sprayed by the ants around the nest, but still wanted to feed and its back-and-fro behaviour was evidence of the - at least partial - success of the frantic workers keeping predators at bay. Winged ant have many predators. Some casually feeding on the winged ones, others opportunistically making use of a plentiful, although ephemeral, bonanza. A range of birds fall in the latter category, starlings and sparrows feed on the winged ants - sometimes using fly-catcher techniques - and seagulls have been seen feeding on them up in the sky. While reading a paper on this, I remembered that last year, on the day the ants emerged, I looked up in the sky and saw many small flying things and thought they might be the flying ants. When I looked more closely I saw they were seagulls, and was surprised at how many there were, well over a hundred, soaring very high up. I took a shot (below) and forgot about it. They were most likely feeding on the winged ants that had been carried high by thermals in their swarming mating flight.Seagull flock feeding on swarming ants (26/07/10)This is the nest in the bottom right hand corner of the top photoWorkers around a nest with winged ants emerging (26/07/10)ReferenceJames Baird and Andrew J. Meyerriecks (1965). Birds Feeding on an Ant Mating Swarm. The Wilson Bulletin, 77 (1), 89-91.Gilbert S. Grant (1992) Opportunistic Foraging on Swarming Ants by Gulls, Shorebirds, and Grackles. The Chat, 56, 80-82.... Read more »
James Baird, Andrew J. Meyerriecks. (1965) Birds Feeding on an Ant Mating Swarm. The Wilson Bulletin, 77(1), 89-91. info:/
Head cheese may not be for everyone but it has an intensely devoted following. Most head cheese recipes call for the removal of brain, eyes, and ears before preparation, but purists scoff at this and include everything except bones. It is doubtful that Upper Paleolithic humans made head cheese; it is too time consuming. It [...]... Read more »
Prat S, Péan SC, Crépin L, Drucker DG, Puaud SJ, Valladas H, Lázničková-Galetová M, van der Plicht J, & Yanevich A. (2011) The oldest anatomically modern humans from far southeast europe: direct dating, culture and behavior. PloS one, 6(6). PMID: 21698105
Italian news is reporting the discovery of the Lady of Introd, a 5,000-year-old skeleton found near the town of Aosta in the Alps, about half-way between Geneva and Turin. Not much has been said yet, and this appears to be the fullest extent of the reports (via La Stampa):
The Lady of Introd (credit: AostaOggi)
E' stata soprannominata la "Signora di Introd" e dopo 5000 anni la sua sepoltura è ancora perfetta. Lo scheletro di questa donna ancora misteriosa e ancora senza età, è stata ritrovato all’interno della propria tomba ad Introd, paese alpino di poco più di 600 abitanti, non lontano da Aosta. Rannicchiata sul fianco destro e con il capo rivolto a nord ovest, non ha attorno nessun oggetto di corredo funebre. I resti della signora sono già stati trasferiti in laboratorio, dove nei prossimi giorni saranno oggetto di analisi approfondite per determinarne l'età, le abitudini alimentari e la causa di morte. L’Assessore all’Istruzione e Cultura Laurent Viérin esprime“grande soddisfazione per questo importante ritrovamento, unico nel suo genere, che testimonia la ricchezza e la qualità del patrimonio archeologico valdostano e della nostra storia.” Il ritrovamento è avvenuto durante i sondaggi archeologici per l’ampliamento della scuola materna di Introd, vicino alla chiesa, al castello e all'antico granaio. Al termine delle indagini su tutta l'area, il ritrovamento dello scheletro non porrà comunque alcun ostacolo alla realizzazione del previsto ampliamento scolastico. Il Soprintendente, l' architetto Roberto Domaine, sottolinea che “il compito della Soprintendenza è quello di garantire una tutela capillare dei Beni culturali in modo da acquisire tutte quelle conoscenze storiche che poi diventano patrimonio dell’intera comunità”.For those of you who don't read Italian, the 5,000-year-old skeleton was discovered recently in the tiny town of Introd (pop: 618), during excavation work to create an addition to a school. The skeleton has been assessed as female, and she was buried on her right side with her head facing west. No grave goods accompanied the burial. The skeleton has already been excavated and moved to a laboratory, where researchers propose to figure out age-at-death, diet, and possible causes or contributors to her death.
This area of the Italian Alps was occupied in historical times by the Salassi tribe. They were defeated and enslaved by the Romans, and the town became Augusta Praetorium Salassorum (now Aosta) in 25 BC. Prior to that, I don't know much about the area. If this skeleton can indeed be carbon-dated to the 3rd millennium BC (nowhere does it say how they assessed the skeleton at five millennia old!), it makes the Lady of Introd relatively contemporaneous with Oetzi the Iceman in the late Neolithic. A dietary analysis of the Lady of Introd would be quite interesting. Various dietary analyses done on Oetzi - whose last meals were quite well preserved - indicate he dined on a lot of meat, as well as einkorn wheat and barley (Dickson et al. 2000).
As I'm putting the finishing touches on my article on isotope analyses of the Imperial Roman diet, I've become quite interested in the differential consumption of wheat/barley and millet. Wheat and barley have a distinctly different carbon isotope signature than does millet, but few palaeodietary studies have been done to look at the prevalence of millet in the Italian peninsula and the differences among the populations that consumed it. By the Bronze Age in Italy, people from the far north of the Italian peninsula were eating their fair share of millet, particularly compared to their contemporaries in southern Italy (Tafuri et al. 2009). Even though quite a bit is known about the timing of the introduction of domesticated plants into Italy during the Neolithic, we still know little about the intensity of cultivation of various cereals. The diets of Oetzi and the Lady of Introd are therefore quite interesting primarily because they can provide direct evidence for differences in cereal consumption in the Neolithic. They are just two data points, but I hope the dietary analysis of the Lady of Introd reveals some interesting data to answer questions about Neolithic diets.
* Hat tip to Alessandra Cinti for posting this news story on Facebook.
Dickson JH, Oeggl K, Holden TG, Handley LL, O'Connell TC, & Preston T (2000). The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 355 (1404), 1843-9 PMID: 11205345.
Tafuri MA, Craig OE, & Canci A (2009). Stable isotope evidence for the consumption of millet and other plants in Bronze Age Italy. American Journal of Physical Anthropology, 139 (2), 146-53 PMID: 19051259.... Read more »
Dickson JH, Oeggl K, Holden TG, Handley LL, O'Connell TC, & Preston T. (2000) The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 355(1404), 1843-9. PMID: 11205345
Human rotavirus particles - http://faculty.riohondo.edu
We've all experienced it; that is, the awful unwell sickness that overwhelms you when you've picked up a nasty viral infection. Remember the last time you had a cold or the 'flu - when coughs, headaches, sore muscles, vomiting, diarrhea and general fatigue forced you to remain in bed. Yet, just exactly how does the virus manage to do this to you? Especially when in some cases your sickness allowed the virus to spread from you to an uninfected family member; sometimes there is an evolutionary advantage to making you unwell. A recent paper published in PLoS Pathogens this week (which can be read here) investigates the molecular mechanisms behind why the oft' fatal rotavirus causes those infected to vomit and through doing so sheds light on possible therapeutic strategies.
A gut villus . http://rezidentiat.3x.ro
This research isn't just aimed at answering some obscure academic problem - although it does do it - rotavirus induced gastroenteritis is serious business worldwide, with over half a million deaths each year (and many, many more hospitalised) mostly due to severe dehydration caused by the excessive vomiting and diarrhea. In many countries, the rotavirus vaccines just haven't reached the population at large and the reasons why this virus causes vomiting and diarrhea are poorly understood - hence this paper.
Now, vomiting - like many physiological processes - is controlled by our brain. Usually vomiting is induced by eating something nasty and is hence a kind of defense mechanism to rid ourselves of any harmful things within the gut. In order to sense if there is anything bad in your intestines, the brain is wired up to it's surface through what is known as the enteric nervous system or ENS. This mesh of neurons is connected to particular endocrine sensor cells (see left), called enterochromaffin cells (EC cells) that line our intestines and respond to the harmful stuff through the release of chemical messengers - like serotonin (5-HT), which in turn activate the ENS and end up inducing vomiting and diarrhea via our brain. But, specifically how does rotavirus fit in here?
A straightforward hypothesis here would be that following ingestion of rotavirus, it would infect the EC cells lining the gut and somehow alter them to release serotonin and stimulate vomiting/diarrhea. And so, the used a primary EC tumour cell line to show that rotavirus does indeed infect the cells. So, now that the virus infects the cell, is this how it causes induction of the ENS? A rapid induction of calcium release was observed soon after infection as well as a quick secretion of serotonin - which itself is dependent on calcium signalling yet the fact that this release occured so soon after addition of virus suggested that replication was not responsible for it - maybe something in the virus particle or something that was in the solution with the virus was to blame? Following seperation of virus particles from the culture media used to grow it, the group showed that the virus particles themselves were not behind it. The group tracked this effect down to NSP4, a protein secreted from rotavirus infected cells following infection and would therefore have been carried over with the virus in these experiments. In the end it was this protein itself that was responsible for the induction of calcium signalling and downstream serotonin release.
Gut villi from mice infected with rotavirus. Arrows indicate rotavirus infected cells (those with large vacuoles) and stars indicated EC cells stained brown. Below, red = rotavirus and green = serotonin and yellow = colocalisation or a rotavirus infected EC cell. Yellow cells are rare - non-EC infected cells (enterocytes) are not.
All done and dusted now? No - up to this point, all work was done under tissue culture conditions in vitro - all be it, mostly in primary cells. The group then moved on to a small-animal mouse model of rotavirus infection to determine if this was the case in vivo - does rotavirus infect EC cells and induce calcium/serotonin signalling that stimulates gut neurons to induce vomiting/diarrhea. This could not have been addressed in cell culture. Following mouse infection, cross-sections of the gut wall were studied to determine the location of rotavirus infected cells and EC cells (see above). Many of the enterocyte cells lining the mouse gut were infected while only rarely were the EC cells targeted - despite what was observed in vitro. Yet for this model to work, rotavirus did not require infection of EC cells as NSP4, the protein behind this effect is secreted from cells and could hence stimulate EC from a distance. In the mouse, the group show that serotonin administration results in diarrhea (oddly, mice do not - and cannot - vomit) and also rotavirus infection leads to the activation of regions in the brain associated with sickness in humans (done through fos staining of brain sections).
A model for how rotavirus makes us vomit/diarrhea
This work has built up a kind of nice and simple picture of a mechanism of rotavirus causes vomiting and diarrhea. They have shown that the virus is able to enter and replicate inside epithelial cells and endcocrine cells lining the gut; they showed that this led to the release of serotonin - the stimulator of vomiting/diarrhea - and that this was down to NSP4 synthesis and release and finally that mice infected with rotavirus activated brain regions associated with vomiting and diarrhea.
The model: (see above) - Rotavirus infects gut cells - expresses and releases NSP4 - NSP4 stimulates calcium signalling and serotonin release from nearby EC cells - serotonin stimulates close by neurons that activate vomiting/diarrhea areas of the brain, which causes serious fluid loss, dehydration and subsequent death. Also this results in rapid spread of virus particles and transmission of infection.
The good thing is now, with this mechanism at hand, we may be able to partially inhibit this response and save the lives of many children and prevent the spread of rotavirus in these populations. Luckily for us, a number of generic - and hence cheap - already in use anti-sickness tab... Read more »
Hagbom, M., Istrate, C., Engblom, D., Karlsson, T., Rodriguez-Diaz, J., Buesa, J., Taylor, J., Loitto, V., Magnusson, K., Ahlman, H.... (2011) Rotavirus Stimulates Release of Serotonin (5-HT) from Human Enterochromaffin Cells and Activates Brain Structures Involved in Nausea and Vomiting. PLoS Pathogens, 7(7). DOI: 10.1371/journal.ppat.1002115
Everyone knows what narcolepsy looks like from movies like the ridiculous display in Deuce Bigalow (one of the ‘adorable misfit bunch of suitors’) to other more subdued examples like Mike in My Own Private Idaho. Oh, and when I say that, I mean people know the stereotype of the instantaneous drop during dinner into a [...]
... Read more »
Mignot E. (2001) A commentary on the neurobiology of the hypocretin/orexin system. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 25(5 Suppl). PMID: 11682267
Maret S, & Tafti M. (2005) Genetics of narcolepsy and other major sleep disorders. Swiss medical weekly, 135(45-46), 662-5. PMID: 16453205
Nigel Barber of The Daily Beast (Psychology Today) has posted on a forthcoming article in which he shows that the level of atheism increases with the quality of life. Barber explains the trend as follows: The reasons that churches lose ground in developed countries can be summarized in market terms. First, with better science, and [...]... Read more »
Barber, N. (2011) A Cross-National Test of the Uncertainty Hypothesis of Religious Belief. Cross-Cultural Research. DOI: 10.1177/1069397111402465
Every year 3500 children under the age of fifteen die in industrialized nations as a result of abuse. In a CAPRA seminar, John Devaney talked about the characteristics of these deaths, about best practices in child death reviews, and about lessons learned to improve child protection. ... Read more »
Devaney, J., Lazenbatt, A., & Bunting, L. (2011) Inquiring into Non-Accidental Child Deaths: Reviewing the Review Process. British Journal of Social Work, 41(2), 242-260. DOI: 10.1093/bjsw/bcq069
Stop monkeying around and pass me a leaf
Chimpanzees in Budongo Forest in Uganda regularly employ leaves as 'napkins' to wipe their penis after sex, researchers discovered
The authors of a study called High Frequency of Postcoital Penis Cleaning in Budongo Chimpanzees do not beat about the bush. "We report on postcoital penis cleaning in chimpanzees," they write. "In penis cleaning, leaves are employed as 'napkins' to wipe clean the penis after sex. Alternatively, the same cleaning motion can be done without leaves, simply using the fingers. Not all chimpanzee communities studied across Africa clean their penes and, where documented, the behaviour is rare. By contrast, we identify postcoital penis cleaning in Budongo Forest, Uganda, as customary."
My first thought: What about masturbation?
The Guardian doesn't mention it at all, but the paper does... once. Its little more than a passing acknowledgement, however, all mentions from there on out are specific to coitus, and the data included in their tables follow suit.
Masturbation is a behavior distinct from copulation. The two end in orgasm for the male, but the resemblances end there. The two activities serve entirely different purposes: coitus is for reproduction and social purposes, masturbation (in males) is for monitoring and controlling ejaculate output.
Which is not to say it is impossible that the two activities could have overlapping purposes. That's where this study starts to come into play, or could come into play. But, the paper chooses not to examine masturbation activities in this context. I'm not sure quite why, to be honest.
Take to the baboons: I've seen them almost always finger clean after they pluck the rooster, but I cannot think of a single copulation which involved cleaning. Granted, copulations are much messier affairs, but its the female who dart after sex. The male generally follows leisurely behind for a few paces, or sits down and starts grunting. That'd be an interesting behavior to compare to across species, and in the case of masturbation, it really should not be difficult at all to gather data.
Unless chimps aren't into jerking off as much as most other social primates. I really think I would have heard about it if that was the case.
A final aside: it would be great to see some, you know, significance statistics for the data in this paper. Otherwise, fun read!
Thanks to Pfeng or Retrochef or whatever she prefers to call herself these days for the tip on this paper.
O’Hara, S., & Lee, P. (2006). High Frequency of Postcoital Penis Cleaning in Budongo Chimpanzees Folia Primatologica, 77 (5), 353-358 DOI: 10.1159/000093700... Read more »
O’Hara, S., & Lee, P. (2006) High Frequency of Postcoital Penis Cleaning in Budongo Chimpanzees. Folia Primatologica, 77(5), 353-358. DOI: 10.1159/000093700
Do you write about peer-reviewed research in your blog? Use ResearchBlogging.org to make it easy for your readers — and others from around the world — to find your serious posts about academic research.
If you don't have a blog, you can still use our site to learn about fascinating developments in cutting-edge research from around the world.
Research Blogging is powered by SMG Technology.
To learn more, visit seedmediagroup.com.