276 research outputs found
Higher fundamental frequency in bonobos is explained by larynx morphology
Acoustic signals, shaped by natural and sexual selection, reveal ecological and social selection pressures [1]. Examining acoustic signals together with morphology can be particularly revealing. But this approach has rarely been applied to primates, where clues to the evolutionary trajectory of human communication may be found. Across vertebrate species, there is a close relationship between body size and acoustic parameters, such as formant dispersion and fundamental frequency (f0). Deviations from this acoustic allometry usually produce calls with a lower f0 than expected for a given body size, often due to morphological adaptations in the larynx or vocal tract [2]. An unusual example of an obvious mismatch between fundamental frequency and body size is found in the two closest living relatives of humans, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Although these two ape species overlap in body size [3], bonobo calls have a strikingly higher f0 than corresponding calls from chimpanzees [4]. Here, we compare acoustic structures of calls from bonobos and chimpanzees in relation to their larynx morphology. We found that shorter vocal fold length in bonobos compared to chimpanzees accounted for species differences in f0, showing a rare case of positive selection for signal diminution in both bonobo sexes
Cannabis sativa L. oil extract affects neuroinflammation, clinical score, and cannabinoid receptor-1 gene expression in C57bl/6 experimental autoimmune encephalomyelitis
Introduction: Multiple sclerosis (MS) is a degenerative central nervous system disease derived by immune mechanisms, which ultimately results in clinical debilities. Numerous nutraceuticals have been cited to be effective in treatment of central nervous system complications. Objectives: This study investigated the effect of Cannabis sativa L. seed oil on experimental autoimmune encephalomyelitis (EAE). Materials and Methods: Female C57bl/6 mice were assigned randomly into three groups (8 in each). Group-A received no myelin oligodendrocyte glycoprotein (MOG), group B was immunized by MOG and treated with oil, while in group C animals were immunized and treated with normal saline. Clinical scores were recorded every other day throughout the study and after four weeks, all mice were sacrificed and spinal cords were incised for molecular and histopathological evaluations. Results: Significant differences were observed in mean clinical scores between control and experiment groups (P<0.001). Cannabinoid receptor-1 gene expression increased significantly in treatment group (P<0.001). Histopathologic evaluations also showed a significant decrease in overall infiltrated and vacuolated area and immune cells infiltration into the central nervous system in the treatment group (P<0.01). Conclusion: Cannabis sativa L. oil extract administration alleviated inflammation and paralysis in animal model. Therefore, its oil extract might be useful in soothing inflammatory and auto-immune diseases. However, additional research might be required.</jats:p
Food mechanical properties and isotopic signatures in forest versus savannah dwelling eastern chimpanzees
Chimpanzees are traditionally described as ripe fruit specialists with large incisors but relatively small postcanine teeth, adhering to a somewhat narrow dietary niche. Field observations and isotopic analyses suggest that environmental conditions greatly affect habitat resource utilization by chimpanzee populations. Here we combine measures of dietary mechanics with stable isotope signatures from eastern chimpanzees living in tropical forest (Ngogo, Uganda) and savannah woodland (Issa Valley, Tanzania). We show that foods at Issa can present a considerable mechanical challenge, most saliently in the external tissues of savannah woodland plants compared to their tropical forest equivalents. This pattern is concurrent with different isotopic signatures between sites. These findings demonstrate that chimpanzee foods in some habitats are mechanically more demanding than previously thought, elucidating the broader evolutionary constraints acting on chimpanzee dental morphology. Similarly, these data can help clarify the dietary mechanical landscape of extinct hominins often overlooked by broad C3/C4 isotopic categories
Activation of the p53 Transcriptional Program Sensitizes Cancer Cells to Cdk7 Inhibitors
Cdk7, the CDK-activating kinase and transcription factor IIH component, is a target of inhibitors that kill cancer cells by exploiting tumor-specific transcriptional dependencies. However, whereas selective inhibition of analog-sensitive (AS) Cdk7 in colon cancer-derived cells arrests division and disrupts transcription, it does not by itself trigger apoptosis efficiently. Here, we show that p53 activation by 5-fluorouracil or nutlin-3 synergizes with a reversible Cdk7asinhibitor to induce cell death. Synthetic lethality was recapitulated with covalent inhibitors of wild-type Cdk7, THZ1, or the more selective YKL-1-116. The effects were allele specific; a CDK7asmutation conferred both sensitivity to bulky adenine analogs and resistance to covalent inhibitors. Non-transformed colon epithelial cells were resistant to these combinations, as were cancer-derived cells with p53-inactivating mutations. Apoptosis was dependent on death receptor DR5, a p53 transcriptional target whose expression was refractory to Cdk7 inhibition. Therefore, p53 activation induces transcriptional dependency to sensitize cancer cells to Cdk7 inhibition. Kalan et al. find that activation of the p53 tumor suppressor protein in human colon cancer-derived cells can induce transcriptional dependency on Cdk7, analogous to constitutive dependencies described in other tumors driven by oncogenic transcription factors. This work provides a proof of concept for combining p53-activating agents with Cdk7 inhibitors to elicit synthetic lethality. Keywords: Cdk7; p53; colon cancer; synthetic lethality; transcription; 5-fluorouracil; nutlin-3; apoptosis; chemical genetics; CDK inhibitorNational Institutes of Health (U.S.) (Grant HG002668
Optimising messages and images for e-cigarette warnings
Background: The US Food and Drug Administration (FDA) requires electronic cigarettes (e-cigarettes) to have a single addiction warning, but many other health harms are associated with vaping and warnings grow stale over time. We aimed to develop new warning messages and images to discourage e-cigarette use. Methods: Participants were 1629 US adults who vaped or smoked. We randomised each participant to evaluate 7 of 28 messages on newly developed warning themes (metals exposure, DNA mutation, cardiovascular problems, chemical exposure, lung damage, impaired immunity, addiction), and the current FDA-required warning (total of 8 messages). Then, participants evaluated images of hazards (eg, metal), internal harms (eg, organ damage) or people experiencing harms. Results: Regarding intended effects, new warning themes all discouraged vaping more than the current FDA-required warning (all p<0.001), led to greater negative affect (all p<0.001) and led to more anticipated social interactions (all p<0.001). The most discouraging warnings were about toxic metals exposure. Regarding unintended effects, the new themes led to more stigma against people who vape (6 of 7 themes, p<0.001) and led to a greater likelihood of thinking vaping is more harmful than smoking (all 7 themes, p<0.001), although unintended effects were smaller than intended effects. Images of harms (internal or people experiencing) discouraged vaping more than images of hazards (all p<0.001). Discussion: Vaping warning policies should communicate a broader range of hazards and harms, beyond addiction, to potentially increase awareness of health harms. Images of internal harm or people experiencing harms may be particularly effective at discouraging vaping
Primate Archaeology Evolves
Since its inception, archaeology has traditionally focused exclusively on humans and our direct ancestors. However, recent years have seen archaeological techniques applied to material evidence left behind by non-human animals. Here, we review advances made by the most prominent field investigating past non-human tool use: primate archaeology. This field combines survey of wild primate activity areas with ethological observations, excavations and analyses that allow the reconstruction of past primate behaviour. Because the order Primates includes humans, new insights into the behavioural evolution of apes and monkeys also can be used to better interrogate the record of early tool use in our own, hominin, lineage. This work has recently doubled the set of primate lineages with an excavated archaeological record, adding Old World macaques and New World capuchin monkeys to chimpanzees and humans, and it has shown that tool selection and transport, and discrete site formation, are universal among wild stone-tool-using primates. It has also revealed that wild capuchins regularly break stone tools in a way that can make them difficult to distinguish from simple early hominin tools. Ultimately, this research opens up opportunities for the development of a broader animal archaeology, marking the end of archaeology’s anthropocentric era
Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.
Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
Novelty Response of Wild African Apes to Camera Traps
Temperament and personality research in humans and nonhuman animals measures behavioral variation in individual, population, or species-specific traits with implications for survival and fitness, such as social status, foraging and mating success [1–5]. Curiosity and risk-taking tendencies have been studied extensively across taxa by measuring boldness and exploration responses to experimental novelty exposure [3,4,6–15]. Here, we conduct a natural field experiment using wildlife monitoring technology to test variation in the reaction of wild great apes (43 groups of naïve chimpanzees, bonobos and western gorillas, across 14 field sites in Africa) to a novel object, the camera-trap. Bonobo and gorilla groups demonstrated a stronger looking impulse towards the camera-trap device compared to chimpanzees, suggesting higher visual attention and curiosity. Bonobos were also more likely to show alarm and other fearful behaviors, although such neophobic (and conversely, neophilic) responses were generally rare. Among all three species, individuals looked at cameras longer when they were young, were associating with fewer individuals, and did not live near a long-term research site. Overall, these findings partially validate results from great ape novelty paradigms in captivity [7,8]. We further suggest that species-typical leadership styles [16] and social and environmental effects, including familiarity with humans, best explain novelty responses of wild great apes. In sum, this study illustrates the feasibility of large-scale field experiments and the importance of both intrinsic and extrinsic factors in shaping animal curiosity
Modified Alvarado Scoring System as a diagnostic tool for Acute Appendicitis at Bugando Medical Centre, Mwanza, Tanzania
<p>Abstract</p> <p>Background</p> <p>Decision-making in patients with acute appendicitis poses a diagnostic challenge worldwide, despite much advancement in abdominal surgery. The Modified Alvarado Scoring System (MASS) has been reported to be a cheap and quick diagnostic tool in patients with acute appendicitis. However, differences in diagnostic accuracy have been observed if the scores were applied to various populations and clinical settings. The purpose of this study was to evaluate the diagnostic value of Modified Alvarado Scoring System in patients with acute appendicitis in our setting.</p> <p>Methods</p> <p>A cross-sectional study involving all patients suspected to have acute appendicitis at Bugando Medical Centre over a six-month period between November 2008 and April 2009 was conducted. All patients who met the inclusion criteria were consecutively enrolled in the study. They were evaluated on admission using the MASS to determine whether they had acute appendicitis or not. All patients underwent appendicectomy according to the hospital protocol. The decision to operate was the prerogative of the surgeon or surgical resident based on overall clinical judgment and not the MASS. The diagnosis was confirmed by histopathological examination. Data was collected using a pre-tested coded questionnaire and analyzed using SPSS statistical computer software.</p> <p>Results</p> <p>A total number of 127 patients were studied. Their ages ranged from eight to 76 years (mean 29.64 ± 12.97). There were 37 (29.1%) males and 90 (70.9%) females (M: F = 1:2.4). All patients in this study underwent appendicectomy. The perforation rate was 9.4%. Histopathological examination confirmed appendicitis in 85 patients (66.9%) and the remaining 42 patients had normal appendix giving a negative appendicectomy rate of 33.1% (26.8% for males and 38.3% for females). The sensitivity and specificity of MASS in this study were 94.1% (males 95.8% and females 88.3%) and 90.4% (males 92.9% and females 89.7%) respectively. The Positive Predictive Value and Negative Predictive Value were 95.2% (males 95.5% and females 90.6%) and 88.4% (males 89.3% and females 80.1%) respectively. The accuracy of MASS was 92.9% (males 91.5% and females 87.6%).</p> <p>Conclusion</p> <p>The study shows that use of MASS in patients suspected to have acute appendicitis provides a high degree of diagnostic accuracy and can be employed at Bugando Medical Centre to improve the diagnostic accuracy of acute appendicitis and subsequently reduces negative appendicectomy and complication rates. However, additional investigations may be required to confirm the diagnosis in case of atypical presentation.</p
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