538 research outputs found
Social rank overrides environmental and community fluctuations in determining meat access by female chimpanzees in the Taï National Park, Côte d’Ivoire
Meat, long hypothesized as an important food source in human evolution, is still a substantial component of the modern human diet, with some humans relying entirely on meat during certain times of the year. Understanding the socio-ecological context leading to the successful acquisition and consumption of meat by chimpanzees (Pan troglodytes), our closest living relative, can provide insight into the emergence of this trait because humans and chimpanzees are unusual among primates in that they both (i) hunt mammalian prey, (ii) share meat with community members, and (iii) form long-term relationships and complex social hierarchies within their communities. However, females in both human hunter-gatherer societies as well as chimpanzee groups rarely hunt, instead typically accessing meat via males that share meat with group members. In general, female chimpanzee dominance rank affects feeding competition, but so far, the effect of female dominance rank on meat access found different results within and across studied chimpanzee groups. Here we contribute to the debate on how female rank influences meat access while controlling for several socio-ecological variables. Multivariate analyses of 773 separate meat-eating events collected over more than 25 years from two chimpanzee communities located in the Taï National Park, Côte d’Ivoire, were used to test the importance of female dominance rank for being present at, and for acquiring meat, during meat-eating events. We found that high-ranking females were more likely to be present during a meat-eating event and, in addition, were more likely to eat meat compared to the subordinates. These findings were robust to both large demographic changes (decrease of community size) and seasonal ecological changes (fruit abundance dynamics). In addition to social rank, we found that other female properties had a positive influence on presence to meat-eating events and access to meat given presence, including oestrus status, nursing of a small infant, and age. Similar to findings in other chimpanzee populations, our results suggest that females reliably acquire meat over their lifetime despite rarely being active hunters. The implication of this study supports the hypothesis that dominance rank is an important female chimpanzee property conferring benefits for the high-ranking females
Inhibition of the JAK/STAT Signaling Pathway in Regulatory T Cells Reveals a Very Dynamic Regulation of Foxp3 Expression
The IL-2/JAK3/STAT-5 signaling pathway is involved on the initiation and
maintenance of the transcription factor Foxp3 in regulatory T cells (Treg) and
has been associated with demethylation of the intronic Conserved Non Coding
Sequence-2 (CNS2). However, the role of the JAK/STAT pathway in controlling
Foxp3 in the short term has been poorly investigated. Using two different
JAK/STAT pharmacological inhibitors, we observed a detectable loss of Foxp3
after 10 min. of treatment that affected 70% of the cells after one hour.
Using cycloheximide, a general inhibitor of mRNA translation, we determined
that Foxp3, but not CD25, has a high turnover in IL-2 stimulated Treg. This
reduction was correlated with a rapid reduction of Foxp3 mRNA. This loss of
Foxp3 was associated with a loss in STAT-5 binding to the CNS2, which however
remains demethylated. Consequently, Foxp3 expression returns to normal level
upon restoration of basal JAK/STAT signaling in vivo. Reduced expression of
several genes defining Treg identity was also observed upon treatment. Thus,
our results demonstrate that Foxp3 has a rapid turn over in Treg partly
controlled at the transcriptional level by the JAK/STAT pathway
Expression and DNA methylation of TNF, IFNG and FOXP3 in colorectal cancer and their prognostic significance.
BACKGROUND: Colorectal cancer (CRC) progression is associated with suppression of host cell-mediated immunity and local immune escape mechanisms. Our aim was to assess the immune function in terms of expression of TNF, IFNG and FOXP3 in CRC.
METHODS: Sixty patients with CRC and 15 matched controls were recruited. TaqMan quantitative PCR and methylation-specific PCR was performed for expression and DNA methylation analysis of TNF, IFNG and FOXP3. Survival analysis was performed over a median follow-up of 48 months.
RESULTS: TNF was suppressed in tumour and IFNG was suppressed in peripheral blood mononuclear cells (PBMCs) of patients with CRC. Tumours showed enhanced expression of FOXP3 and was significantly higher when tumour size was >38 mm (median tumour size; P=0.006, Mann-Whitney U-test). Peripheral blood mononuclear cell IFNG was suppressed in recurrent CRC (P=0.01). Methylated TNFpromoter (P=0.003) and TNFexon1 (P=0.001) were associated with significant suppression of TNF in tumours. Methylated FOXP3cpg was associated with significant suppression of FOXP3 in both PBMC (P=0.018) and tumours (P=0.010). Reduced PBMC FOXP3 expression was associated with significantly worse overall survival (HR=8.319, P=0.019).
CONCLUSIONS: We have detected changes in the expression of immunomodulatory genes that could act as biomarkers for prognosis and future immunotherapeutic strategies
Does Vesta Have Moons?
Previous searches for moons around Vesta have found nothing to an upper limit of 22.5 magnitude, that corresponds to 44 +/- 4 m diameter assuming the same albedo as Vesta. The Dawn mission's approach phase has dedicated satellite search observations consisting of two mosaic sequences bracketing the first observations of a complete rotation of Vesta scheduled for early July, 2011. In addition, we use the approach optical navigation image sequences for initial satellite searches. We will report any findings from these observations, and upper limits of magnitude and size
Spatiotemporal Models of an Estuarine Fish Species to Identify Patterns and Factors Impacting Their Distribution and Abundance
Microbial diversity and community composition of caecal microbiota in commercial and indigenous Indian chickens determined using 16s rDNA amplicon sequencing
Different alpha diversity indices for each sample of university farm data estimated using QIIME for primer pair P2 data. OTUs were clustered at >â97% similarity. (XLSX 12 kb
Systemic corticosteroids in dermatological practice. Part I: Main adverse effects
Systemic corticosteroids have been used in dermatological practice for approximately 60 years due to their anti-inflammatory and immunosuppressive effects. The challenge of corticosteroid therapy is to counterbalance the desirable actions and undesirable pharmacological effects. Unfortunately, advanced understanding of the mechanisms of action of corticosteroids has not resulted in the development of minimal toxicity regimens. In this article, we report the main pharmacological properties of systemic corticosteroids, their major indications in clinical practice and the adverse effects of high doses and/or prolonged administration.Há quase 60 anos os corticosteróides sistêmicos têm sido amplamente utilizados na área de dermatologia, trazendo benefícios para muitas doenças em decorrência de suas ações antiinflamatórias e imunossupressoras. O desafio de seu uso consiste em contrabalançar os efeitos benéficos e as atividades farmacológicas indesejáveis. Infelizmente, os avanços no conhecimento sobre os mecanismos de ação dos corticosteróides não resultaram no desenvolvimento de regimes com mínima toxicidade. Dessa maneira, este artigo de revisão discorre sobre os aspectos farmacológicos dos corticosteróides sistêmicos, bem como suas principais indicações de uso e efeitos colaterais da administração em altas doses e/ou por longos períodos de tempo.UNIFESPHospital Central da Santa Casa de São Paulo Departamento de Clínica Médica Serviço de DermatologiaHospital Central da Santa Casa de São Paulo Clínica de DermatologiaUNIFESPSciEL
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