Post List

  • September 19, 2014
  • 05:06 AM
  • 5 views

Air travel may cause pneumothorax in BHD patients

by Lizzie Perdeaux in BHD Research Blog

One concern many BHD patients have is whether it is safe to take commercial flights, or whether this would increase the chances of a pneumothorax. A recently published study, by Professor Pieter Postmus and his team at the VU Medical … Continue reading →... Read more »

Postmus PE, Johannesma PC, Menko FH, & Paul MA. (2014) In-Flight Pneumothorax: Diagnosis May Be Missed because of Symptom Delay. American journal of respiratory and critical care medicine, 190(6), 704-5. PMID: 25221882  

  • September 19, 2014
  • 04:08 AM
  • 5 views

Increasing parental age and autism severity?

by Paul Whiteley in Questioning Answers

An interesting paper by David Geier and colleagues [1] (open-access here) caught my eye recently, concluding that there was a lack of support for the suggestion that: "increasing parental age was associated with increasing autism spectrum disorder phenotypic severity"."the snozzberries taste like snozzberries".Before progressing through the paper and its possible implications, the eagle-eyed out there might have already spotted the name Dr Brian Hooker on the authorship list of the Geier paper. Outside of his other peer-reviewed work [2], I probably only need to mention the letters 'CDC' and everything that has [so far] followed including (at the time of writing) a removal statement for another paper [3]...Anyhow, the idea behind the Geier paper stems from the quite widely disseminated notion that there may be a connection between increasing parental age at conceiving and an increased risk of offspring autism. I've covered it a few times on this blog (see here and see here). The authors elaborate about a recent hypothesis suggesting that "there must be a linkage between increasing genetic load and increasing parental age in autism spectrum disorder pathogenesis" based on studies like the one from Kong and colleagues [4] (covered in a previous post) and Lampi and colleagues [5]. Further, that as a consequence of an increasing genetic load (all those SNPs et al), "there should be a significant relationship between increasing parental age and increasing autism spectrum disorder phenotypic severity of subjects diagnosed with an autism spectrum disorder".The paper is open-access but maybe a few details are in order:Participants (N=351), diagnosed with DSM-IV autism, were drawn from "patients presenting for outpatient genetic consultations at the ASD Centers, LLC". Mean age was approximately 9 years of age, most male and most reporting developmental regression following birth. Details of age of parents at time of offspring birth were analysed alongside use of the ATEC (Autism Treatment Evaluation Checklist) at initial clinical presentation. These variables formed the crux of the study.Results: "Overall, it was observed that no significant relationships were observed between increasing autism spectrum disorder phenotypic severity and increasing maternal or paternal age". Except, that is, for something that seemed to suggest that older maternal age at birth of child seemed to correlates with "improved sociability" in offspring. The authors report that their observations: "provide important insights into the apparent lack of a relationship between increasing parental age and increasing autism spectrum disorder phenotypic severity".Of course one has to be careful with any study of correlation/association, particularly when it comes to something as simple as just looking at ATEC scores of severity of behaviours in the autism domains and parents age at time of birth of their children. I personally would also have liked to see some further discussion on whether the broader autism phenotype (BAP) for example, might have been an influencing variable too in light of studies like the one from Hasegawa and colleagues [6]. Also, the participant group is quite large - as the authors note - but even there I think back to the sort of sample numbers that those [big data] studies in Taiwan are including (see here) as to where we should be heading.That all being said, I don't want to downplay the Geier results. Another quote might be useful here: "most observed de novo genetic events are unconnected to an autism spectrum disorder diagnosis, and those that do confer risk are distributed across many genes and are not necessarily sufficient for disease". This ties in rather nicely with the recent discussions on common variations and autism risk (see here) and how Gaugler and colleagues [7] questioned how much weight to give to de novo mutations in the grand scheme of autism 'causation'. This also might imply that non-genetic events, or at least non-structural genetic events headed under the general banner of environment might also play some contributory role to at least some cases of autism. Again, something which has cropped up on this blog before (see here).Music to close. Given the recent vote near these parts, one of Scotland's most famous exports... Franz Ferdinand and Do You Want To.----------[1] Geier DA. et al. An Evaluation of the Effect of Increasing Parental Age on the Phenotypic Severity of Autism Spectrum Disorder. J Child Neurol. 2014 Aug 27. pii: 0883073814541478.[2] Hooker B. et al. Methodological issues and evidence of malfeasance in research purporting to show thimerosal in vaccines is safe. Biomed Res Int. 2014;2014:247218.[3] Hooker BS. Measles-mumps-rubella vaccination timing and autism among young african american boys: a reanalysis of CDC data. Transl Neurodegener. 2014; 3: 16.[4] Kong A. et al. Rate of de novo mutations and the importance of father's age to disease risk. Nature. 2012 Aug 23;488(7412):471-5.[5] Lampi KM. et al. Parental age and risk of autism spectrum disorders in a Finnish national birth cohort. J Autism Dev Disord. 2013 Nov;43(11):2526-35.[6] Hasegawa C. et al. Broader autism phenotype in mothers predicts social responsiveness in young children with autism spectrum disorders. Psychiatry Clin Neurosci. 2014 Jun 6. doi: 10.1111/pcn.12210.[7] Gaugler T. et al. Most genetic risk for autism resides with common variation. Nature Genetics. 2014. July 20.----------... Read more »

  • September 19, 2014
  • 12:13 AM
  • 11 views

The neuroscience behind scratching an itch

by William Lu in The Quantum Lobe Chronicles

The beautiful experience of alleviating an itch, the vigorous scratching of skin cells, and the white flakes that float away slowly and gently like a whimsical dream.If only those with chronic itching problems could describe their conditions in such a serene way. In the latest edition of Nature Neuroscience, Diana Bautista and colleagues (2014) review the literature on the underlying mechanism of the itch at the molecular and cellular level within the peripheral and central nervous systems. They describe what drives acute and chronic itching and even quote the famous Buddhist Nagarjuna in their abstract."There is a pleasure when an itch is scratched. But to be without an itch is more pleasurable still".They provide the reader with a few examples of neurological disorders where chronic itching can become a problem:1. multiple sclerosis2. diabetic neuropathy3. shingles They also boldly state that the act of itching serves no biological purpose.Because I currently do not have institutional access to any research journals, I can only surmise that this article is an incredibly interesting read (although there is a greater likelihood that the details would go over my head). But alas, I now suffer from an inability to rid myself of this nagging itch to read Bautista et al.'s article so that I can write a decent blog post about it.You can check out the first page here.You can also enjoy this Times read on the mysteries of the itch and how a molecule known as neuropeptide natriuretic polypeptide b (Nppb) may be the answer.References:Bautista, D., Wilson, S., & Hoon, M. (2014). Why we scratch an itch: the molecules, cells and circuits of itch Nature Neuroscience, 17 (2), 175-182 DOI: 10.1038/nn.3619The above image is from http://www.byebyedoc.com/wp-content/uploads/2013/04/itching.jpeg... Read more »

  • September 18, 2014
  • 11:45 PM
  • 6 views

Experimental and comparative oncology: zebrafish, dogs, elephants

by Artem Kaznatcheev in Evolutionary Games Group

One of the exciting things about mathematical oncology is that thinking about cancer often forces me to leave my comfortable arm-chair and look at some actually data. No matter how much I advocate for the merits of heuristic modeling, when it comes to cancer, data-agnostic models take second stage to data-rich modeling. This close relationship […]... Read more »

Gallaher, J., & Anderson, A.R. (2013) Evolution of intratumoral phenotypic heterogeneity: the role of trait inheritance. Interface Focus, 3(4), 20130016. arXiv: 1305.0524v1

  • September 18, 2014
  • 05:00 PM
  • 5 views

Trunk biomechanics, hip and knee kinematics in patellofemoral pain

by Craig Payne in Running Research Junkie

Trunk biomechanics, hip and knee kinematics in patellofemoral pain... Read more »

  • September 18, 2014
  • 05:00 PM
  • 7 views

The influence of running speed on ankle and knee joint moments

by Craig Payne in Running Research Junkie

The influence of running speed on ankle and knee joint moments... Read more »

  • September 18, 2014
  • 04:52 PM
  • 23 views

How to Look for Otters

by Denise O'Meara in Denise O'Meara

In the first of a new series of posts about “How to Look for Mammals”, I take a look at one of our semi aquatic species, the Eurasian otter. The Eurasian otter is distributed across Europe and into Eurasia, but it is absent and restricted to small isolated pockets in some European countries. However, the species is slowly starting to recover across Western Europe. Ireland is a stronghold for the otter, and marks the western most point of the otter’s distribution. It is thought that the Irish climate with lots of fresh water makes it an ideal habitat for the otter....... Read more »

Reid N, Hayden B, Lundy MG, Pietravalle S, McDonald RA, & Montgomery WI. (2013) National Otter Survey of Ireland 2010/12. Irish Wildlife Manuals No. 76. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland. info:other/

  • September 18, 2014
  • 04:09 PM
  • 26 views

Coffee Drinkers Have Trouble Talking About Emotions?

by Neuroskeptic in Neuroskeptic_Discover

People who drink a lot of coffee – and other caffeinated beverages – find it more difficult to identify and describe their own emotions. This is the claim of a new study, published in the Journal of Psychoactive Drugs, from Australian researchers Michael Lyvers and colleagues: Caffeine use and alexithymia in university students. “Alexithymia” – […]The post Coffee Drinkers Have Trouble Talking About Emotions? appeared first on Neuroskeptic.... Read more »

Lyvers M, Duric N, & Thorberg FA. (2014) Caffeine use and alexithymia in university students. Journal of psychoactive drugs, 46(4), 340-6. PMID: 25188705  

  • September 18, 2014
  • 03:44 PM
  • 21 views

MERS-CoV vaccine

by thelonevirologist in Virology Tidbits

MERS-CoV is the causative agent of a severe and fatal respiratory illness in humans with no known effective antiviral therapy or vaccine. Although MERS-CoV infections have been reported from countries outside the Arabian peninsula, local transmission with the exception of family cluster of three cases in Tunisia (with the index case being infected in the KSA) has been limited to the Kingdom of Saudi Arabia, the Kingdom of Jordan, Qatar, Oman, and the United Arab Emirates. Recent developments on MES-CoV vaccines are discussed.... Read more »

Corman VM, Jores J, Meyer B, Younan M, Liljander A, Said MY, Gluecks I, Lattwein E, Bosch BJ, Drexler JF.... (2014) Antibodies against MERS coronavirus in dromedary camels, Kenya, 1992-2013. Emerging infectious diseases, 20(8), 1319-22. PMID: 25075637  

Yang L, Wu Z, Ren X, Yang F, Zhang J, He G, Dong J, Sun L, Zhu Y, Zhang S.... (2014) MERS-related betacoronavirus in Vespertilio superans bats, China. Emerging infectious diseases, 20(7), 1260-2. PMID: 24960574  

  • September 18, 2014
  • 12:58 PM
  • 35 views

Is Stress Eating Away at You? No, Literally…

by Gabriel in Lunatic Laboratories

Ever wonder why, when people are too stressed, they are often grouchy, grumpy, nasty, distracted or forgetful? It may not be something you’ve done, in fact it turns out stress is literally tearing apart the brain. By this I mean that researchers have just highlighted a fundamental synaptic mechanism that explains the relationship between chronic stress and the loss of social skills and cognitive impairment. When triggered by stress, an enzyme attacks a synaptic regulatory molecule in the brain. In other words, when people use the colloquialism “what’s eating you?” the answer might just be, stress.... Read more »

van der Kooij, M., Fantin, M., Rejmak, E., Grosse, J., Zanoletti, O., Fournier, C., Ganguly, K., Kalita, K., Kaczmarek, L., & Sandi, C. (2014) Role for MMP-9 in stress-induced downregulation of nectin-3 in hippocampal CA1 and associated behavioural alterations. Nature Communications, 4995. DOI: 10.1038/ncomms5995  

  • September 18, 2014
  • 11:11 AM
  • 31 views

Genetics of Social Skills: Oxytocin Receptor Gene

by William Yates, M.D. in Brain Posts

Social neuroscience is an emerging emphasis in the field of neuroscience research.Social cognition is the subset of cognitive functions related to social processes and includes factors such as facial recognition, social memory and ability to form friendships and other social bonds.Impairment in social cognition is a known feature in autism, schizophrenia and other mental disorders. This type of impairment can produce significant problems in life adjustment, employment and human attachment.Genetic features appear to be important in human social cognition. Biological factors influence social behavior including the action of the hormone oxytocin.Dave Skuse along with colleagues in England, Finland and the U.S. recently published an important study examining the oxytocin receptor gene and social cognition.Their study used a family study design of 198 families from the U.K. and Finland with a single identified with high-functioning autism.This strategy was used with recognition that social cognition deficits are common in family members of those with autism and autism spectrum disorder.Probands with autism and family members had genetic testing for oxytocin gene polymorphism status along with the related vasopression gene. All participants completed a standardized test known as the Facial Recognition Memory Test (FRMT). Facial recognition and memory are key elements in social cognition and social function.The key findings from the study included the following:Oxytocin receptor polymorphism SNP rs237887 was strongly linked to deficits in facial recognition memoryHomozygous status for this SNP was associated with approximately a one standard deviation reduction in performance on the FRMT.This deficit was found in the autism group along with a significant number of undiagnosed family membersThe authors note their finding is consistent with other studies linking this specific SNP polymorphism with measures of empathy, autism traits and emotional responsivity to betrayal cues. The authors also note their results add to rodent animal model studies finding a key role for the oxytocin and vasopressin system in modulating social cognition and social behavior.These types of studies hold promise for potential drug development to reduce social impairment in those with autism and other disorders of social cognition.Readers with more interest in this research can access the free full-text manuscript by clicking on the PMID link in the citation below.Photo from the Dingle peninsula in Ireland is from the author's files.Follow the author on Twitter WRY999Skuse DH, Lori A, Cubells JF, Lee I, Conneely KN, Puura K, Lehtimäki T, Binder EB, & Young LJ (2014). Common polymorphism in the oxytocin receptor gene (OXTR) is associated with human social recognition skills. Proceedings of the National Academy of Sciences of the United States of America, 111 (5), 1987-92 PMID: 24367110... Read more »

Skuse DH, Lori A, Cubells JF, Lee I, Conneely KN, Puura K, Lehtimäki T, Binder EB, & Young LJ. (2014) Common polymorphism in the oxytocin receptor gene (OXTR) is associated with human social recognition skills. Proceedings of the National Academy of Sciences of the United States of America, 111(5), 1987-92. PMID: 24367110  

  • September 18, 2014
  • 08:00 AM
  • 24 views

Pythons and the Land - The Bangladesh Python Project Part IV --Guest Post--

by David Steen in Living Alongside Wildlife

By Jon Hakim

Make sure to start at Part I.

“Snake call!  It's the python.  Are you up?  We got a call for the python.”









The words were almost the same, but I woke up to see that
Caesar's face held a grimace.  The
call he feared had come. 






Let's back up to the night before.



In the last post I left you in a moment of triumph.  Kanai had led four of us right to our
target species... Read more »

Rahman, Shahriar Caesar, & et al. (2013) Monsoon does matter: annual activity patterns in a snake assemblage from Bangladesh. The Herpetological Journal, 203-208. info:/

  • September 18, 2014
  • 04:50 AM
  • 33 views

Anxiety and sensory over-responsivity linked to gut issues in autism

by Paul Whiteley in Questioning Answers

"The name's Lonnegan! Doyle Lonnegan!"Consider this micropost an extension of some previous discussions on this blog about how gastrointestinal (GI) issues present in cases of autism might show some connection to the presence of anxiety and sensory issues (see here). Today I'm discussing further research by Micah Mazurek and colleagues [1] which follows a previous publication by this author [2] on this topic.In the latest paper, Dr Mazurek and colleagues describe the course of abdominal pain in 225 children diagnosed with an autism spectrum disorder (ASD). Of the quarter of participants who presented with "chronic abdominal pain at baseline", the majority (over 80%) still had the same GI issue at 1-year follow-up. Indeed, a further 25% of those who did not present with abdominal pain at the start of the study finished the study with such an issue. The authors conclude: "Abdominal pain appears to be common and persistent among children with ASD". Further, anxiety and sensory over-responsivity also seemed to correlate with bowel features which is probably not unexpected.Yes, you might indeed say that this study was based on "the parent-reported GI Symptom Inventory Questionnaire" among other things and so one has to be slightly cautious about inferring states. But as I've mentioned before on this blog, parents/primary caregivers tend to be pretty good at picking up when such issues are present in their children (see here) if not precise to all the technical details [3].Perhaps the most important detail about the Mazurek study is their mention of the word 'pain' and how so many of their cohort seemed to be enduring quite a bit of it for such a long period of time. You wouldn't think that there was guidance on identifying and managing these issues [4] would you? And whilst we are on the topic of GI issues and autism, I might as well bring your attention to the potentially important question asked by Heitzer and colleagues [5]: Should clinical trial research of psychotropic medication in autism control for gastrointestinal symptoms? Answers on a postcard please (although I will blogging about this paper in times to come).So then, how about William Shatner singing Pulp to close. Replacing a Sheffield accent with a Montreal one... mmm, maybe he needs a little Henderson's Relish with that cheese?----------[1] Mazurek MO. et al. One-year course and predictors of abdominal pain in children with autism spectrum disorders: The role of anxiety and sensory over-responsivity. Research in Autism Spectrum Disorders. 2014; 8: 1508-1515.[2] Mazurek MO. et al. Anxiety, sensory over-responsivity, and gastrointestinal problems in children with autism spectrum disorders. J Abnorm Child Psychol. 2013 Jan;41(1):165-76.[3] Gorrindo P. et al. Gastrointestinal dysfunction in autism: parental report, clinical evaluation, and associated factors. Autism Res. 2012 Apr;5(2):101-8.[4] Buie T. et al. Evaluation, Diagnosis, and Treatment of Gastrointestinal Disorders in Individuals With ASDs: A Consensus Report. Pediatrics. 2010; 125: S1-S18.[5] Heitzer AM. et al. Should clinical trial research of psychotropic medication in autism control for gastrointestinal symptoms? J Clinical Pharmacology. 2014. 6 May.----------Mazurek, M., Keefer, A., Shui, A., & Vasa, R. (2014). One-year course and predictors of abdominal pain in children with autism spectrum disorders: The role of anxiety and sensory over-responsivity Research in Autism Spectrum Disorders, 8 (11), 1508-1515 DOI: 10.1016/j.rasd.2014.07.018... Read more »

  • September 17, 2014
  • 05:56 PM
  • 61 views

Why are ethical standards higher in science than in business and media?

by Richard Kunert in Brain's Idea

Facebook manipulates user content in the name of science? Scandalous! It manipulates user content in the name of profit? No worries! Want to run a Milgram study these days? Get bashed by your local ethics committee! Want to show it on TV? No worries. Why do projects which seek knowledge have higher ethical standards than […]... Read more »

Kramer AD, Guillory JE, & Hancock JT. (2014) Experimental evidence of massive-scale emotional contagion through social networks. Proceedings of the National Academy of Sciences of the United States of America, 111(24), 8788-90. PMID: 24889601  

Milgram, S. (1963) Behavioral Study of obedience. The Journal of Abnormal and Social Psychology, 67(4), 371-378. info:/doi: 10.1037/h0040525

  • September 17, 2014
  • 02:49 PM
  • 39 views

September 17, 2014

by Erin Campbell in HighMag Blog

All good things must end—even the focal adhesions that are so key to cell migration. Today’s notable image is the first live cell visualization of ECM degradation at focal adhesions, in a recent paper that reports the link between CLASPs, exocytosis, and focal adhesion turnover. Cell migration depends on the precisely-timed formation of focal adhesions (FAs) that link the crawling cell to the extracellular matrix (ECM). FAs serve as anchor points for the crawling cell, yet must later disassemble in order to allow continued movement of the cell. A recent paper describes how CLASP proteins link FA-associated microtubules, exocytosis, and FA turnover. CLASP proteins are +TIP proteins, which means that they are found on the growing ends of microtubules. Stehbens and colleagues found that the clustering of CLASPs around FAs correlates with the timing of FA disassembly, and that CLASPs are required for ECM degradation. Stehbens and colleagues also found that the tethering of microtubules to FAs, via CLASPs, serve as a transport pathway for exocytic vesicles at FAs. The images above are the first live cell images of ECM degradation (visualized as dark regions, top panel) at FAs (magenta).BONUS! For more information on the scanning angle interference microscopy used in this paper, check out Matthew Paszek’s Nature Methods paper here.Stehbens, S., Paszek, M., Pemble, H., Ettinger, A., Gierke, S., & Wittmann, T. (2014). CLASPs link focal-adhesion-associated microtubule capture to localized exocytosis and adhesion site turnover Nature Cell Biology, 16 (6), 561-573 DOI: 10.1038/ncb2975Adapted by permission from Macmillan Publishers Ltd, copyright ©2014 ... Read more »

  • September 17, 2014
  • 01:24 PM
  • 46 views

Biofilms: Using Bacteria for new Designer Nanomaterials

by Gabriel in Lunatic Laboratories

For most people biofilms conjure up images of slippery stones in a streambed and dirty drains. While there are plenty of "bad" biofilms around – they are even the same stuff that causes pesky dental plaque and a host of other more serious medical problems – a team of researchers sees biofilms as a robust new platform for designer nanomaterials that could clean up polluted rivers, manufacture pharmaceutical products, fabricate new textiles, and more.... Read more »

Peter Q. Nguyen,, Zsofia Botyanszki,, Pei Kun R. Tay,, & Neel S. Joshi. (2014) Programmable biofilm-based materials from engineered curli nanofibres. Nature Communications. info:/10.1038/ncomms5945

  • September 17, 2014
  • 12:48 PM
  • 47 views

Live Fast, Die Young: Evolutionary Outcomes of an Asteroid Impact

by Melissa Chernick in Science Storiented

A new semester has started and with it an influx of new students into the lab has begun. Busy has become my middle name. So when I was looking around for a paper to write about I wanted something different and cool. Not exactly hard to find in science. The asteroid known as 2012 DA14 will narrowly miss Earth this Friday, the closest known asteroid flyby on record. And by close we’re talking within the orbits of many communications satellites. This got me thinking about and looking for recent papers about asteroids. It didn't take me long to come by an interesting new paper about the dino-killing Chicxulub bolide impact.As of now, it is widely accepted that an epic asteroid collision ended the 135 million year reign of the dinosaurs. The Cretaceous-Paleogene boundary (KPB) extinction event is marked by the Chicxulub (CHEEK-sheh-loob) impact on the Yucatán Peninsula in Mexico. This asteroid or comet is estimated to have been about 6 miles (10 km), releasing as much energy as 100 trillion tons of TNT that caused a crater more can 110 miles (180 km) across! This impact coincides with a mass extinction event that includes the dinosaurs. Dramatic climate swings caused by the dust kicked up into the atmosphere were likely the culprit behind many of these extinctions. Before we go further, take a second to think about what you know about this extinction event. You probably think of the mass die-off of the dinosaurs and the subsequent rise of the mammals, right? But, as I have in the past, I’ll now pose a question: What about the plants?A new paper published yesterday in PLOS Biology asks just that question. We know that in temperate North America the Chicxulub impact resulted in the extinction of over 50 percent of the plant species. From an evolutionary and ecological stand-point, that’s a lot of competitors that were taken out of the game. However, the environment was dramatically altered as well, changing to a cold and dark “impact winter.” Combined, these factors created a unique selection scenario for certain ecological strategies. The new paper takes a close look at the functional traits associated with these strategies. The researchers measured fossil leaf assemblages spanning a 2.2 million year interval across the KPB, assessing four differing selection scenarios for functional traits. First, wrap your head around the concept of “functional traits.” These are characteristics that define species in terms of their ecological roles. In the case of leaves, these include leaf mass per area (LMA; Do you make a big, expensive leaf or a light, cheap one?) and leaf minor vein density (VD; Do you have more veins to transport lots of water?), among many others. Because leaves are the food producers, these traits are linked to plant growth and fitness. Next, you can relate these traits to the “leaf economic spectrum” (LES) that contrasts species with inexpensive short-lived leaves with fast returns on carbon and nutrients (deciduous, angiosperm, broadleaf) to costly long-lived leaves with slow returns (coniferous, gymnosperm, evergreen). The former is typically selected for in a less resource variable environment and vice versa. From this, you can get a more global perspective on changes in species composition.The researchers measured LMA and VD for fossil leaf assemblages spanning the KPB. To do this they digitally photographed specimens that could be measured and confidently reconstructed. Then they used Photoshop to digitally separate the leaf from its rock matrix. For LMA they used ImageJ to calculate leaf area and petiole width, and then ran these numbers through empirical scaling functions (a.k.a. equations). For VD, they used a MATLAB line-counting program to isolate the veins and then manually counted the number of vein-line intersections, computing the mean distance between veins  as the sum of all line counts divided by the sum of all distances (a.k.a. a slightly less complicated equation). They ran a few scenarios to account for site and region plant specificity as well.They found LMA to decrease and VD to increase across this time period. Even changes just these two traits reflect large physiological and biological shifts in plant functioning over a relatively short period of time. According to their data, the Chicxulub impact led to the selective extinction of species with slow strategies. This caused a directional selection away from evergreen species along with a stabilizing selection of deciduous angiosperms. The authors pose a few hypotheses in their discussion that are worth mentioning. The higher observed VD in angiosperms, and their ensuing selection, could have been driven by declining atmospheric carbon dioxide (CO2), which selects for higher hydraulic capacity. This CO2 hypothesis would, of course, not really hold water (no pun intended) for nonangiosperms and shade species, but the authors suggest that the observed increase in VD is more likely to be a direct consequence of the impact selecting for specific leaf economic strategies rather than ongoing-longer term climate change.In this case, slow and steady did not win the race.  Blonder B, Royer DL, Johnson KR, Miller I, & Enquist BJ (2014). Plant Ecological Strategies Shift Across the Cretaceous-Paleogene Boundary. PLoS biology, 12 (9) PMID: 25225914(image via above citation)... Read more »

  • September 17, 2014
  • 11:28 AM
  • 49 views

Antidepressants Modulate Memory in the Healthy Brain

by William Yates, M.D. in Brain Posts

The mechanism of antidepressant drug response is not well understood.One theory posits antidepressant effects are only seen in those with clinical depression leaving the healthy brain unchanged.In a previous post, I outlined a study demonstrating effects of antidepressants on brain connectivity measures in the healthy brain.A recent fMRI study extends our understanding of the potential mechanisms for antidepressant drugs.CT Cerqueira and colleagues from Brazil studied the effects of the antidepressant clomipramine in a series of human subjects without a personal or family history of depression or other major psychiatric disorder.Subjects were started on a trial of clomipramine 10 mg increasing to 40 mg daily as tolerated.These healthy subjects then rated whether they noted any positive subjective response to clomipramine as defined by:increased mental efficiency and cogntive functionimproved mood and sense of well-beingawareness of significant change from usual subjective stateFour of sixteen subjects were rated as "responders" to the low dose clomipramine trial. Subjects provided a report of autobiographical memories in the previous six months that were grouped into positive (happy) versus negative (dysphoria/irritability).The key findings from the study included:Clomipramine "responders" showed enhanced blood flow (BOLD changes) with negative emotion cuesThis enhanced blood flow was located in the left tempero-parieto-occipital cortex and the left frontoparietal cortexNo differences were noted in blood flow between responders and non-responders with positive emotional cuesThe authors note there findings support a modulation of negative autobiographical memory in some individuals with healthy brains without an active mood disorder.It is unclear why this effect was limited to only about 25% of the healthy subject group. It is possible these "responders" to clomipramine had a form of sub-clinical depression.Alternately, the study supports the possibility of a more generalized effect of antidepressants not limited to those with a clinical mood disorder.Reduction of distress to negative emotional memories is a known clinical effect of an antidepressant effect in those with mood disorder.The enhanced brain activity in this study with clomipramine is located in brain regions known to be active in processing emotional stimuli and modulation of the negative response to dysphoric memories.The current study is limited by a small sample size but supports further study of antidepressant brain effects in healthy versus depressed subjects. This type of research may provide insight into designing more effective antidepressant drugs.Readers with more interest in this research can access the free full-text article by clicking on the PMID link below.Landscape of Dingle peninsula in Ireland is from the author's files.Follow the author on Twitter WRY999Cerqueira CT, Sato JR, de Almeida JR, Amaro E Jr, Leite CC, Gorenstein C, Gentil V, & Busatto GF (2014). Healthy individuals treated with clomipramine: an fMRI study of brain activity during autobiographical recall of emotions. Translational psychiatry, 4 PMID: 24984192... Read more »

  • September 17, 2014
  • 10:02 AM
  • 55 views

An Unusual Case of Scurvy found in the Maya

by Katy Meyers in Bones Don't Lie

Scurvy is caused by a lack of vitamin C in one’s nutrition. Historical accounts of the disease are first recorded in 1845, noting the presence of rosy patches of skin, […]... Read more »

  • September 17, 2014
  • 09:46 AM
  • 51 views

Video Tip of the Week: GOLD, Genomes OnLine Database

by Mary in OpenHelix

Yes, I know some people suffer from YAGS-malaise (Yet Another Genome Syndrome), but I don’t. I continue to be psyched for every genome I hear about. I even liked the salmon lice one. And Yaks. The crowd-funded Puerto Rican parrot project was so very neat. These genomes may not matter much for your everyday life, […]... Read more »

Liolios Konstantinos, Lynette Hirschman, Ioanna Pagani, Bahador Nosrat, Peter Sterk, Owen White, Philippe Rocca-Serra, Susanna-Assunta Sansone, Chris Taylor, & Nikos C. Kyrpides. (2012) The Metadata Coverage Index (MCI): A standardized metric for quantifying database metadata richness. Standards in Genomic Sciences, 6(3), 444-453. DOI: http://dx.doi.org/10.4056/sigs.2675953  

Field Dawn, Tanya Gray, Norman Morrison, Jeremy Selengut, Peter Sterk, Tatiana Tatusova, Nicholas Thomson, Michael J Allen, Samuel V Angiuoli, & Michael Ashburner. (2008) The minimum information about a genome sequence (MIGS) specification. Nature Biotechnology, 26(5), 541-547. DOI: http://dx.doi.org/10.1038/nbt1360  

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