69 research outputs found
Acute Fulminant Colitis Caused by Idiopathic Mesenteric Inflammatory Veno-Occlusive Disease
Mesenteric inflammatory veno-occlusive disease (MIVOD) is an uncommon but important cause of bowel inflammation. MIVOD is characterised by lymphocytic inflammation and non-thrombotic occlusion of the mesenteric venules and veins. We present the case of a young man who presented with acute fulminant colitis, requiring colectomy. The differential diagnosis, pathogenesis and treatment are discussed. This case illustrates the rapid progression from ‘well’ to ‘colectomy’ that can occur with MIVOD. MIVOD should be considered in the differential diagnosis of colitis that does not respond to conventional medical treatment
Human Young Children as well as Adults Demonstrate ‘Superior’ Rapid Snake Detection When Typical Striking Posture Is Displayed by the Snake
Humans as well as some nonhuman primates have an evolved predisposition to associate snakes with fear by detecting their presence as fear-relevant stimuli more rapidly than fear-irrelevant ones. In the present experiment, a total of 74 of 3- to 4-year-old children and adults were asked to find a single target black-and-white photo of a snake among an array of eight black-and-white photos of flowers as distracters. As target stimuli, we prepared two groups of snake photos, one in which a typical striking posture was displayed by a snake and the other in which a resting snake was shown. When reaction time to find the snake photo was compared between these two types of the stimuli, its mean value was found to be significantly smaller for the photos of snakes displaying striking posture than for the photos of resting snakes in both the adults and children. These findings suggest the possibility that the human perceptual bias for snakes per se could be differentiated according to the difference of the degree to which their presence acts as a fear-relevant stimulus
Production and perception of situationally variable alarm calls in wild tufted capuchin monkeys (Cebus apella nigritus)
Many mammalian and avian species produce conspicuous vocalizations upon encountering a predator, but vary their calling based on risk urgency and/or predator type. Calls falling into the latter category are termed “functionally referential” if they also elicit predator-appropriate reactions in listeners. Functionally referential alarm calling has been well documented in a number of Old World monkeys and lemurs, but evidence among Neotropical primates is limited. This study investigates the alarm call system of tufted capuchin monkeys (Cebus apella nigritus) by examining responses to predator and snake decoys encountered at various distances (reflecting differences in risk urgency). Observations in natural situations were conducted to determine if predator-associated calls were given in additional contexts. Results indicate the use of three call types. “Barks” are elicited exclusively by aerial threats, but the call most commonly given to terrestrial threats (the “hiccup”) is given in nonpredatory contexts. The rate in which this latter call is produced reflects risk urgency. Playbacks of these two call types indicate that each elicits appropriate antipredator behaviors. The third call type, the “peep,” seems to be specific to terrestrial threats, but it is unknown if the call elicits predator-specific responses. “Barks” are thus functionally referential aerial predator calls, while “hiccups” are better seen as generalized disturbance calls which reflect risk urgency. Further evidence is needed to draw conclusions regarding the “peep.” These results add to the evidence that functionally referential aerial predator alarm calls are ubiquitous in primates, but that noncatarrhine primates use generalized disturbance calls in response to terrestrial threats
Portuguese propolis disturbs glycolytic metabolism of human colorectal cancer in vitro
Propolis is a resin collected by bees from plant buds and exudates, which is further processed through the activity of bee enzymes. Propolis has been shown to possess many biological and pharmacological properties, such as antimicrobial, antioxidant, immunostimulant and antitumor activities. Due to this bioactivity profile, this resin can become an alternative, economic and safe source of natural bioactive compounds.Antitumor action has been reported in vitro and in vivo for propolis extracts or its isolated compounds; however, Portuguese propolis has been little explored. The aim of this work was to evaluate the in vitro antitumor activity of Portuguese propolis on the human colon carcinoma cell line HCT-15, assessing the effect of different fractions (hexane, chloroform and ethanol residual) of a propolis ethanol extract on cell viability, proliferation, metabolism and death.
METHODS:
Propolis from Angra do Heroísmo (Azores) was extracted with ethanol and sequentially fractionated in solvents with increasing polarity, n-hexane and chloroform. To assess cell viability, cell proliferation and cell death, Sulforhodamine B, BrDU incorporation assay and Anexin V/Propidium iodide were used, respectively. Glycolytic metabolism was estimated using specific kits.
RESULTS:
All propolis samples exhibited a cytotoxic effect against tumor cells, in a dose- and time-dependent way. Chloroform fraction, the most enriched in phenolic compounds, appears to be the most active, both in terms of inhibition of viability and cell death. Data also show that this cytotoxicity involves disturbance in tumor cell glycolytic metabolism, seen by a decrease in glucose consumption and lactate production.
CONCLUSION:
Our results show that Portuguese propolis from Angra do Heroísmo (Azores) can be a potential therapeutic agent against human colorectal cancer.We thank the Portuguese Science and Technology Foundation (FCT) for VMG fellowship (ref. SFRH/BI/33503/2008). The authors thank Mr. Antonio Marques from Frutercoop - Azores, who kindly collected and provided the propolis sample for the study
The ontogeny of antipredator behavior: age differences in California ground squirrels (Otospermophilus beecheyi) at multiple stages of rattlesnake encounters
Newborn offspring of animals often exhibit fully functional innate antipredator behaviors, but they may also require learning or further development to acquire appropriate responses. Experience allows offspring to modify responses to specific threats and also leaves them vulnerable during the learning period. However, antipredator behaviors used at one stage of a predator encounter may compensate for deficiencies at another stage, a phenomenon that may reduce the overall risk of young that are vulnerable at one or more stages. Few studies have examined age differences in the effectiveness of antipredator behaviors across multiple stages of a predator encounter. In this study, we examined age differences in the antipredator behaviors of California ground squirrels (Otospermophilus beecheyi) during the detection, interaction, and attack stages of Pacific rattlesnake (Crotalus oreganus) encounters. Using free-ranging squirrels, we examined the ability to detect free-ranging rattlesnakes, snake-directed behaviors after discovery of a snake, and responses to simulated rattlesnake strikes. We found that age was the most important factor in snake detection, with adults being more likely to detect snakes than pups. We also found that adults performed more tail flagging (a predator-deterrent signal) toward snakes and were more likely to investigate a snake’s refuge when interacting with a hidden snake. In field experiments simulating snake strikes, adults exhibited faster reaction times than pups. Our results show that snake detection improves with age and that pups probably avoid rattlesnakes and minimize time spent in close proximity to them to compensate for their reduced reaction times to strikes
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
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Something Scary Is Out There: Remembrances of Where the Threat Was Located by Preschool Children and Adults with Nighttime Fear
Young children frequently report imaginary scary things in their bedrooms at night. This study examined the remembrances of 140 preschool children and 404 adults selecting either above, side, or below locations for a scary thing relative to their beds. The theoretical framework for this investigation posited that sexual-size dimorphism in Australopithecus afarensis, the presumed human ancestor in the Middle Pliocene, constrained sleeping site choice to mitigate predation. Smaller-bodied females nesting in trees would have anticipated predatory attacks from below, while male nesting on the ground would have anticipated attacks from their side. Such anticipation of nighttime attacks from below is present in many arboreal primates and might still persist as a cognitive relict in humans. In remembrances of nighttime fear, girls and women were predicted to select the below location and males the side location. Following interviews of children and adult questionnaires, multinomial log-linear analyses indicated statistically significant interactions (p < 0.001) of sex by location for the combined sample and each age class driven, in part, by larger frequencies of males selecting the side location and females selecting the below location. Data partitioning further revealed that males selected the side location at larger frequencies (p < 0.001) than the below location, whereas female selection of side and below locations did not differ significantly. While indicative of evolutionary persistence in cognitive appraisal of threat locations, the female hypothesis did not consider natural selection acting on assessment of nighttime terrestrial threats following the advent of early Homo in the Late Pliocene
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Drawings of representational images by upper paleolithic humans and their absence in neanderthals reflect historical differences in hunting wary game
One characteristic of the transition from the Middle Paleolithic to the Upper Paleolithic in Europe was the emergence of representational charcoal drawings and engravings by Aurignacian and Gravettian artists. European Neanderthals never engaged in representational drawing during the Middle and Early Upper Paleolithic, a property that might reflect less developed visuomotor coordination. This article postulates a causal relationship between an evolved ability of anatomically modern humans to throw spears accurately while hunting and their ability to draw representational images from working memory. Unlike Neanderthals, archaic and anatomically modern humans in sub-Saharan Africa adopted longer-range hunting practices using hand-cast spears as a compensation for the emergence of increasingly wary game. For Neanderthals, paleoclimatic fluctuations likely precluded consistent hunting of cold-adapted game, a property making game more approachable for close-range hunting with thrusting spears. As evidence of less historical wariness of humans, many of the species hunted by Neanderthals were eventually domes-ticated. Due to strong sources of natural selection on archaic and anatomically modern humans for effective hunting, the parietal cortex that integrates visual imagery and motor coordination expanded progressively, yielding the globular shape of the human cranium that is not evident in Neanderthals. To characterize how the cognitive properties employed for throwing spears and drawing line work are similar, the Upper Paleolithic drawings of animals in Chauvet cave, France, are discussed in the speculative context of how these artists engaged simultaneously in overt attention to guide their hand movements and covert attention to their mental images during the drawing process
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