Post List

  • September 17, 2014
  • 05:56 PM
  • 8 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
  • 6 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
  • 15 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
  • 11 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
  • 12 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
  • 14 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
  • 11 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  

  • September 17, 2014
  • 08:30 AM
  • 10 views

Does Your Cat Sniff New Food?

by CAPB in Companion Animal Psychology Blog

New research investigates which feline behaviours show that cats find food tasty. Photo: FreeBirdPhotos / ShutterstockThere are certain things we can take for granted when feeding the cat: the pitiful miaows that become increasingly strident, the anticipatory purring when you move towards the cat food, and the way the cat wraps herself around your leg as if you’re her best friend ever. But when you put the food down, is there any guarantee she will eat it? Cat food manufacturers have teams of cats that work as food testers, to make sure new foods are as tasty as can be. This study, by Aurélie Becques et al (in press) took place at the Panelis Diana Pet Food Division. Here, cats are housed in groups in an indoor environment with access to the outdoors. Two such groups of cats (17 cats in total) took part in this study.The cats are given free access to kibble for twenty hours of the day, to mimic the most common way of feeding cats in the home. They are fed via a feeding station, which only one cat can enter at a time. The length of time they spend in the station and the amount of food they eat is all measured. A video camera captures their behaviour.The study investigated feline behaviour when eating a Very Palatable Kibble (VPK) compared to a Less Palatable Kibble. In fact, both kibbles were the same (Royal Canin), but different coatings were applied. The coatings were both made of poultry fat and had the same number of calories, but one was previously shown to be very tasty to cats and the other less so. Both sets of cats had in fact been fed these two foods at some point in the past. To further enhance the tastiness of the Very Palatable Kibble, it was mixed with some tuna. This combination was something the cats had not experienced before. It also had the effect of making the VPK slightly less calorie dense.The cats were given a two day test of each type of food. Since this is a working cat food testing environment, in between the sessions reported here, they were given a different food according to the current rotation.The results showed that when cats were offered the Very Palatable Kibble, they ate more each day (81g on average compared to 53g). Because cats made different numbers of visits to the feeding station each day, the researchers compared the first three visits and the last visit of each day. With the exception of the last visit on the first day, the cats ate more of the VPK every time they went to the feeding station.Cats are good at regulating their food intake, and so it is surprising that they ate more calories when fed the VPK. However, since the study only had two days per food, it is possible the cats would have adjusted their food intake over time.Whether the cat was eating in a sitting or standing position, the speed at which it ate, the length of time from approaching the bowl to starting to eat, and the total amount of licking, was the same for the two foods. Previous research has suggested that licking the lips and grooming the face is associated with finding food tasty, whereas cats lick their nose when they don’t like it so much. The researchers sometimes couldn’t tell whether the cat was licking its lips or its nose, especially at night when it was dark, so this remains a question for future research.Sniffing behaviour turns out to be an indicator of a new food’s perceived tastiness. On the first day of LPK, the cats spent a lot more time sniffing the food on the first two visits to the feeding station. The researchers say, “One may have expected that the novelty of the diet should have caused more sniffing. On the contrary the cats tended to sniff more LPK, a diet that they have already experienced, than VPK that they have previously experienced but without the addition of tuna. The tuna was very odorant and it seemed that this odor was attractive enough to elicit eating in a short lapse of time. On the other hand the longer duration of sniffing the LPK diet may correspond to a hesitation to consume a less palatable diet.”The researchers say the cat’s behaviour is an indication of how tasty it finds the food. So if you offer a new food and your cat is sniffing at it, it’s probably not a good sign.Is your cat fussy about food?ReferenceBecques, A., Larose, C., Baron, C., Niceron, C., Feron, C., & Gouat, P. (2014). Behaviour in order to evaluate the palatability of pet food in domestic cats Applied Animal Behaviour Science , 159, 55-61 : 10.1016/j.applanim.2014.07.003 ... Read more »

Becques, A., Larose, C., Baron, C., Niceron, C., Feron, C., & Gouat, P. (2014) Behaviour in order to evaluate the palatability of pet food in domestic cats. Applied Animal Behaviour Science , 55-61. info:/10.1016/j.applanim.2014.07.003

  • September 17, 2014
  • 08:28 AM
  • 12 views

Builders and Blocks – Engineering Blood Vessels with Stem Cells

by Jalees Rehman in The Next Regeneration

Back in 2001, when we first began studying how regenerative cells (stem cells or more mature progenitor cells) enhance blood vessel growth, our group as well as many of our colleagues focused on one specific type of blood vessel: arteries. Arteries are responsible for supplying oxygen to all organs and tissues of the body and arteries are more likely to develop gradual plaque build-up (atherosclerosis) than veins or networks of smaller blood vessels (capillaries). Once the amount of plaque in an artery reaches a critical threshold, the oxygenation of the supplied tissues and organs becomes compromised. In addition to this build-up of plaque and gradual decline of organ function, arterial plaques can rupture and cause severe sudden damage such as a heart attack. The conventional approach to treating arterial blockages in the heart was to either perform an open-heart bypass surgery in which blocked arteries were manually bypassed or to place a tube-like "stent" in the blocked artery to restore the oxygen supply. The hope was that injections of regenerative cells would ultimately replace the invasive procedures because the stem cells would convert into blood vessel cells, form healthy new arteries and naturally bypass the blockages in the existing arteries.... Read more »

Paul JD, Coulombe KL, Toth PT, Zhang Y, Marsboom G, Bindokas VP, Smith DW, Murry CE, & Rehman J. (2013) SLIT3-ROBO4 activation promotes vascular network formation in human engineered tissue and angiogenesis in vivo. Journal of molecular and cellular cardiology, 124-31. PMID: 24090675  

  • September 17, 2014
  • 08:05 AM
  • 20 views

Should I Stay Or Should I Go

by Mark Lasbury in As Many Exceptions As Rules

Bacteria can swarm to conquer new territory or settle into structured biofilms, not unlike tribes that are nomadic versus those that build cities. New research indicates has shed light on the mechanics of swarming and biofilm production, including the function of extracellular DNA and secreted polysaccharides. Both biofilms and swarming depend on quorum sensing, and several new papers have identified chemicals that can interrupt quorum sensing in pathogenic bacteria and therefore prevent disease development.... Read more »

Gloag ES, Turnbull L, Huang A, Vallotton P, Wang H, Nolan LM, Mililli L, Hunt C, Lu J, Osvath SR.... (2013) Self-organization of bacterial biofilms is facilitated by extracellular DNA. Proceedings of the National Academy of Sciences of the United States of America, 110(28), 11541-6. PMID: 23798445  

Alteri CJ, Himpsl SD, Pickens SR, Lindner JR, Zora JS, Miller JE, Arno PD, Straight SW, & Mobley HL. (2013) Multicellular bacteria deploy the type VI secretion system to preemptively strike neighboring cells. PLoS pathogens, 9(9). PMID: 24039579  

  • September 17, 2014
  • 06:29 AM
  • 19 views

Autoimmune disease risk and eating disorders

by Paul Whiteley in Questioning Answers

"We were set up. The cops were waiting for us.""We observed an association between eating disorders and several autoimmune diseases with different genetic backgrounds. Our findings support the link between immune-mediated mechanisms and development of eating disorders".So said the paper by Anu Raevuori and colleagues [1] (open-access) based on an analysis of over 2300 people "treated at the Eating Disorder Unit of Helsinki University Central Hospital between 1995 and 2010" compared with nearly 10,000 control participants (so yes, this was quite a well-powered study).The Raevuori paper is open-access but if you want a few choice details, here goes...Based on a body of research literature looking at a possible association between eating disorders and autoimmune conditions like type 1 diabetes [2], authors set about testing the hypothesis on a large scale on whether "the risk of autoimmune diseases would be increased in individuals with eating disorders both prior and after the onset of the treatment for an eating disorder".Having already mentioned how large a scale the authors' participants groups were, various eating disorder diagnoses were confirmed based on ICD-10 criteria [3] and both research and control populations were assessed for some 30 autoimmune conditions based on existing hospital discharge registry. "Period and lifetime prevalences" were calculated from the data. Results: "Participants with BN [bulimia nervosa] made up the largest patient group (54.0%), followed by those with AN [anorexia nervosa] (38.8%), and those with BED [binge eating disorder] (7.3%)". Over 5% of those diagnosed with an eating disorder had been diagnosed with one or more autoimmune conditions compared with just under 3% of controls when it came to looking at period prevalence (at the onset of treatment). Long quote coming up... "The risk of prior diagnosis of endocrinological autoimmune diseases (OR 3.3, 95% CI 2.4–4.6, P<0.001), of gastroenterological immune-mediated diseases (OR 2.0, 95% CI 1.3–3.1, P = 0.002), and of autoimmune diseases combined (OR 2.1 95% CI 1.7–2.7, P<0.001) was significantly higher among patients than among matched controls".With regards to lifetime prevalence (over the whole study period) "8.9% (N = 209) of patients and 5.4% of control individuals (N = 509) had ever been diagnosed with one or more autoimmune disease". Whilst only looking like a relatively small percentage difference in the rates of autoimmune conditions between the groups, it is the scale of the Raevuori study in terms of participant numbers which gives the data some 'edge'. As the authors also note, their use of the category BED - binge eating disorder - is also another plus to their study given it's recent inclusion into DSM-5 (see here).As I always seem to be about papers mentioned on this blog, I was really quite interested in the results presented by Raevuori et al and their potential implications for how we describe eating disorders and the potential mechanisms involved in onset. Research into autoimmune conditions has recently been producing some rather important associations as per my covering of things like a [possible] link between autoimmune disorders following trauma and PTSD (see here) and even a suggested connection with some epilepsy (see here).Raevuori and colleagues discuss several pertinent mechanisms potentially linking their findings including the ever-present issue of inflammation and: "Pro-inflammatory cytokines and antibodies/autoantibodies against neuronal antigens". They also mention some possible role for "intestinal microflora contributing to the development of cross-reactive neuronal autoantibodies [providing] a link between gut and brain" and the growing fascination with all-things gut microbiome. Their finding of a greater frequency of the inflammatory bowel disease (IBD), Crohn's disease in their eating disorder cohort offers some evidence for this assertion as a function of the growing interest in gut bacteria and IBDs [4].Without hopefully going too far off tangent from the Raevuori paper, I started to think about how these results might also fit in with some of the research done on autism and whether there may be a bigger picture here. Eating disorders have been mentioned alongside the label autism quite a few times in the research literature [5]. My previous discussions on signs of autism in cases of eating disorders (see here) is one example. Likewise, autoimmune conditions and autism also seem to have something of a connection (see here) alongside presented data on markers of autoimmunity in cases of autism (see here and see here). One can perhaps see how the various elements - immune function, inflammation, gut bacteria, gut permeability? - might be intertwined, albeit in a rather complex fashion...?Music then, and Naive by The Kooks.----------[1] Raevuori A. et al. The increased risk for autoimmune diseases in patients with eating disorders. PLoS One. 2014 Aug 22;9(8):e104845.[2] Young V. et al. Eating problems in adolescents with Type 1 diabetes: a systematic review with meta-analysis. Diabet Med. 2013 Feb;30(2):189-98.[3] Herpetz S. et al. The Diagnosis and Treatment of Eating Disorders. Dtsch Arztebl Int. Oct 2011; 108(40): 678–685.[4] Manichanh C. et al. The gut microbiota in IBD. Nat Rev Gastroenterol Hepatol. 2012 Oct;9(10):599-608.[5] Huke V. et al. Autism spectrum disorders in eating disorder populations: a systematic review. Eur Eat Disord Rev. 2013 Sep;21(5):345-51.----------Raevuori A, Haukka J, Vaarala O, Suvisaari JM, Gissler M, Grainger M, Linna MS, & Suokas JT (2014). The increased risk for autoimmune diseases in patients with eating disorders. PloS one, 9 (8) PMID: 25147950... Read more »

Raevuori A, Haukka J, Vaarala O, Suvisaari JM, Gissler M, Grainger M, Linna MS, & Suokas JT. (2014) The increased risk for autoimmune diseases in patients with eating disorders. PloS one, 9(8). PMID: 25147950  

  • September 17, 2014
  • 06:09 AM
  • 21 views

Unwelcome colonisers: biofilm formation on voice prostheses

by socgenmicro in Microbe Post

A human being’s voice is one of their most distinguishing and individual features. Most of us have experienced the frustration of temporarily losing our voices – but for many survivors of laryngeal cancer (cancer of the voice box), this loss … Continue reading →... Read more »

Talpaert, M., Balfour, A., Stevens, S., Baker, M., Muhlschlegel, F., & Gourlay, C. (2014) Candida Biofilm Formation on Voice Prostheses. Journal of Medical Microbiology. DOI: 10.1099/jmm.0.078717-0  

  • September 17, 2014
  • 04:36 AM
  • 21 views

A talking powered smartphone? The chin strap that makes electricity from chewing

by Stuart Farrimond in Guru: Science Blog

Mouths – where would we be without them? We use our jaws for so many essential tasks: eating food, chewing gum, yawning when we are tired from a hard day’s work and, oh let’s not forget, talking. Most of us […]The post A talking powered smartphone? The chin strap that makes electricity from chewing appeared first on Guru Magazine.... Read more »

  • September 17, 2014
  • 12:05 AM
  • 22 views

Not So Competitive Return Rates to Activity Following ACL Reconstruction

by Nicole Cattano in Sports Medicine Research (SMR): In the Lab & In the Field

Only 55% of athletes returned to competitive sport following anterior cruciate ligament (ACL) reconstruction. The debate continues as to whether hamstring or patellar tendon autograft is better. However, factors that may favor return to competitive sport include younger age, male gender, elite sport, and a positive psychological response. ... Read more »

  • September 16, 2014
  • 10:15 PM
  • 34 views

Colon cancer, mathematical time travel, and questioning the sequential mutation model.

by Artem Kaznatcheev in Evolutionary Games Group

On Saturday, I arrived in Columbus, Ohio for the the MBI Workshop on the Ecology and Evolution of Cancer. Today, our second day started. The meeting is an exciting combination of biology-minded mathematicians and computer scientists, and math-friendly biologist and clinicians. As is typical of workshops, the speakers of the first day had an agenda […]... Read more »

Baker AM, Cereser B, Melton S, Fletcher AG, Rodriguez-Justo M, Tadrous PJ, Humphries A, Elia G, McDonald SA, Wright NA.... (2014) Quantification of crypt and stem cell evolution in the normal and neoplastic human colon. Cell reports, 8(4), 940-7. PMID: 25127143  

  • September 16, 2014
  • 07:11 PM
  • 37 views

Breaking battery convention: new study indicates fast charging not necessarily detrimental to cycle lifetimes

by Jonathan Trinastic in Goodnight Earth

New battery research examining the structure of LiFePO4 electrodes during charging indicate that fast charging rates are possible due to a relationship between rate and active intercalation sites.... Read more »

  • September 16, 2014
  • 01:20 PM
  • 49 views

GM plants with modified 'eskimo1' gene have increased 'drought tolerance'

by This Science is Crazy! in This Science Is Crazy!

New study uses siRNA and 35S promoter to regulate multiple genes including ESK1 to improve drought tolerance in Arabidopsis... Read more »

  • September 16, 2014
  • 01:20 PM
  • 41 views

New Cocktail Turns Adult Cells into Stem Cells

by Gabriel in Lunatic Laboratories

For those of us who were following stem cell news, recently the field had a huge setback when a paper, that offered a cheap and novel way to create stem cells, was retracted from publication. Regenerative medicine aims to replace lost or damaged cells, tissues or organs through cellular transplantation, but the promise to a better life has been hampered. Because stem cells derived from human embryos can trigger ethical concerns, a good solution is reprogramming adult cells back to an embryo-like state using a combination of reprogramming factors. Unfortunately that has been easier said than done.... Read more »

Buganim Y, Markoulaki S, van Wietmarschen N, Hoke H, Wu T, Ganz K, Akhtar-Zaidi B, He Y, Abraham BJ, Porubsky D.... (2014) The Developmental Potential of iPSCs Is Greatly Influenced by Reprogramming Factor Selection. Cell stem cell, 15(3), 295-309. PMID: 25192464  

  • September 16, 2014
  • 11:01 AM
  • 49 views

Cannabis-induced Paranoia: Cognitive Mechanisms

by William Yates, M.D. in Brain Posts

Some individuals appear vulnerable to paranoia induced by exposure to tetrahydrocannabinol (THC) in cannabis.The mechanism for this effect is poorly understood.Daniel Freeman from University of Oxford along with colleagues in England and Switzerland recently conducted an interventional research study on this issue.In this study, 121 subjects were recruited to receive injections of THC in a laboratory setting.These subjects were required to have taken cannabis at least once before participation in the study.Additionally, the subjects were required to have experience at least one paranoid thought during the last month as measured by Part B of the Paranoid Thoughts Scale.Subjects were excluded if they had previously been diagnosed with a psychiatric diagnosis, substance use diagnosis, had a first-degree family member with a major mental illness.  Additionally exclusion criteria included presence of a neurological or other significant medical problem, nursing or pregnancy.Subjects received one of three randomized interventions: injection of placebo, injection of 1.5 mg of THC or injection of 1.5 mg of THC preceded by a short 5 minute educational session describing the types of effects possible with exposure to THC.The key findings from the study included the following:Exposure to THC significantly increased ratings of paranoiaExposure to THC increased ratings of negative affect, anomalous experienceExposure to THC reduced working memory capacityIncreases in paranoia were fully explained by increased negative affect and increased anomalous experience effectsReduced working memory effects did not contribute to paranoiaEducational awareness did not appear to significantly modify cognitive effects of THCThe authors note:"The study clearly establishes that THC causes paranoia in vulnerable individuals."They note paranoia is a important psychotic symptom that is "distributed as a quantitative trait in the population". Negative affect and anomalous sensory experiences appear to contribute to increases in paranoia in the THC exposure model.The implications of this study include the importance of reducing negative affect (worry, anxiety and depression) in individuals with paranoia and other signs and symptoms of psychosis.Additionally, individuals with spontaneous paranoid thoughts may be more vulnerable to increased THC-induced paranoia.Individuals with more interest in this study can access the free full-text manuscript by clicking on the PMID in the citation below.Photo of Cliffs of Moher in Western Ireland from the author's files.Follow the author on Twitter WRY999Freeman D, Dunn G, Murray RM, Evans N, Lister R, Antley A, Slater M, Godlewska B, Cornish R, Williams J, Di Simplicio M, Igoumenou A, Brenneisen R, Tunbridge EM, Harrison PJ, Harmer CJ, Cowen P, & Morrison PD (2014). How Cannabis Causes Paranoia: Using the Intravenous Administration of ∆9-Tetrahydrocannabinol (THC) to Identify Key Cognitive Mechanisms Leading to Paranoia. Schizophrenia bulletin PMID: 25031222... Read more »

  • September 16, 2014
  • 06:36 AM
  • 42 views

Should Policy Makers and Financial Institutions Have Access to Billions of Brain Scans?

by The Neurocritic in The Neurocritic

"Individual risk attitudes are correlated with the grey matter volume in the posterior parietal cortex suggesting existence of an anatomical biomarker for financial risk-attitude," said Dr Tymula.This means tolerance of risk "could potentially be measured in billions of existing medical brain scans." 1 -Gray matter matters when measuring risk toleranceLet's pretend that scientists have discovered a neural biomarker that could accurately predict a person's propensity to take financial risks in a lottery. Would it be ethical to release this information to policy makers? That seems to be the conclusion of a new paper published in the Journal of Neuroscience (Gilaie-Dotan et al., 2014):The results will also provide a simple measurement of risk attitudes that could be easily extracted from abundance of existing medical brain scans, and could potentially provide a characteristic distribution of these attitudes for policy makers.If we accept this line of thinking, it's not much of a stretch to imagine that financial institutions, employers, consumer reporting agencies, and dating services could use this information in a discriminatory, preemptive fashion to screen out potentially risky applicants. Or perhaps casinos, lotteries, and predatory lending companies could target these individuals with personalized ads.Conversely, investment firms could vie for traders with the largest right posterior parietal cortices, since they would have the highest tolerance for risk.Or am I being alarmist about the breach of ethics involved in releasing protected medical information to outside entities? Although the authors subtly deter extrapolation to this invasive scenario by using phrases like "characteristic distribution" and "risk attitudes of populations" (as opposed to risk attitudes of individuals), they're pretty clear about the promise of their gray matter measure to inform policy (Gilaie-Dotan et al., 2014):Our finding suggests the existence of a simple biomarker for risk attitude, at least in the midlife [sic] population we examined in the northeastern United States. ...  If generalized to other groups, this finding will also imply that individual risk attitudes could, at least to some extent, be measured in many existing medical brain scans, potentially offering a tool for policy makers seeking to characterize the risk attitudes of populations.Now let's all take a step back and evaluate whether this is currently feasible. The short answer is no (in my view, at least).First, we have to be somewhat skeptical of the study's major conclusion. Voxel-based morphometry (VBM) was to quantify cortical volume from structural MRIs.2 Gray matter volume in a small chunk of the right posterior parietal cortex (PPC) was the only place in the entire cerebral cortex that correlated with individual attitudes toward financial risk. In humans, right lateralized PPC has been strongly implicated in visuospatial attention.Doesn't it seem more plausible that a region like the orbitofrontal cortex (OFC), which has been activated in numerous functional neuroimaging studies of decision making and risk, would show such an association? Studies in primates have demonstrated that economic risk is coded by single neurons in the OFC (O'Neill & Schultz, 2014), and in rats risk preference can be differentiated by OFC neuronal responses (Roitman & Roitman, 2010).The authors do cite an extensive literature on the role of parietal neurons in decision making, but fMRI studies have observed effects of risk preference in left PPC, and uncertainty in bilateral PPC (Huettel et al., 2005, 2006).But what is the purpose of having a larger gray matter volume in PPC in relation to financial risk attitude? Does it allow for a higher "computational capacity" that can accommodate greater risk tolerance? We don't actually know, as Gilaie-Dotan et al. (2014) explain:We do not know precisely how GM volume translates to the neural level. It is possible that volume differences reflect synaptogenesis and dendritic arborization (Kanai and Rees, 2011), but to-date there is no clear evidence of correlation between GM volume measured by VBM and any histological measure, including neuronal density (Eriksson et al., 2009). In contrast to the neural correlate of risk attitude, a participant's attitude toward ambiguity was not associated with structural differences anywhere in the cortex (Gilaie-Dotan et al., 2014). How were these attitudes (or preferences) measured? Experimental economics methods were used to estimate individual preferences for risk (uncertainty with known probabilities) and ambiguity (uncertainty with unknown probabilities).Participants played a game where they could choose between lotteries that varied in monetary value and in the degree of either risk or ambiguity. In the example trial below, the participant chooses either this option, where they stand a 38% chance of winning $18, or the reference option that offers a 50% chance of winning $5.Modified from Fig. 1A (Gilaie-Dotan et al., 2014).There were five reward levels ($5, $9.50, $18, $34, and $65), each fully crossed with three probabilities of winning and three levels of ambiguity around the winning probability, as shown below.Figure 1 (Levy et al., 2012). Risky and ambiguous stimuli. A) In risky stimuli the red and blue areas of each image are proportional to the number of red and blue chips. Three outcome probabilities were used: 13, 25 and 38%. B) In ambiguous stimuli the central part of the image is obscured with a gray occluder. In the gray area the number of chips of each color is unknown, and thus the probability of drawing a chip of a certain color is not precisely known. Three levels of ambiguity were used, where 25, 50 or 75% of the image is occluded.Using a maximum likelihood procedure, the choice data of each participant was fit to a logistic function. Fitting the choice data with a choice function provided estimates for the risk attitude (α) and ambiguity attitude (β) for each person. These were included in multiple regression analyses to determine the neuroanatomical correlates of risk (α) and ambiguity (β) based on the model estimates.3 Two populations of subjects w... Read more »

Gilaie-Dotan, S., Tymula, A., Cooper, N., Kable, J., Glimcher, P., & Levy, I. (2014) Neuroanatomy Predicts Individual Risk Attitudes. Journal of Neuroscience, 34(37), 12394-12401. DOI: 10.1523/JNEUROSCI.1600-14.2014  

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