13,224 research outputs found
Viral Reservoirs in Lymph Nodes of FIV-Infected Progressor and Long-Term Non-Progressor Cats during the Asymptomatic Phase.
BackgroundExamination of a cohort of cats experimentally infected with feline immunodeficiency virus (FIV) for 5.75 years revealed detectable proviral DNA in peripheral blood mononuclear cells (PBMCs) harvested during the asymptomatic phase, undetectable plasma viral RNA (FIV gag), and rarely detectable cell-associated viral RNA. Despite apparent viral latency in peripheral CD4+ T cells, circulating CD4+ T cell numbers progressively declined in progressor animals. The aim of this study was to explore this dichotomy of peripheral blood viral latency in the face of progressive immunopathology. The viral replication status, cellular immunophenotypes, and histopathologic features were compared between popliteal lymph nodes (PLNs) and peripheral blood. Also, we identified and further characterized one of the FIV-infected cats identified as a long-term non-progressor (LTNP).ResultsPLN-derived leukocytes from FIV-infected cats during the chronic asymptomatic phase demonstrated active viral gag transcription and FIV protein translation as determined by real-time RT-PCR, Western blot and in situ immunohistochemistry, whereas viral RNA in blood leukocytes was either undetectable or intermittently detectable and viral protein was not detected. Active transcription of viral RNA was detectable in PLN-derived CD4+ and CD21+ leukocytes. Replication competent provirus was reactivated ex vivo from PLN-derived leukocytes from three of four FIV-infected cats. Progressor cats showed a persistent and dramatically decreased proportion and absolute count of CD4+ T cells in blood, and a decreased proportion of CD4+ T cells in PLNs. A single long-term non-progressor (LTNP) cat persistently demonstrated an absolute peripheral blood CD4+ T cell count indistinguishable from uninfected animals, a lower proviral load in unfractionated blood and PLN leukocytes, and very low amounts of viral RNA in the PLN.ConclusionCollectively our data indicates that PLNs harbor important reservoirs of ongoing viral replication during the asymptomatic phase of infection, in spite of undetectable viral activity in peripheral blood. A thorough understanding of tissue-based lentiviral reservoirs is fundamental to medical interventions to eliminate virus or prolong the asymptomatic phase of FIV infection
Aspects of the population biology of Octopus vulgaris in False Bay, South Africa
The population biology of the octopus Octopus vulgaris was studied from specimens collected by SCUBA in False Bay, South Africa, between 1997 and 1998. In all, 83% of the specimens collected were found in shelter. Small octopuses were more active than large individuals during the day, 37% of the former and 8% of the latter being found outside of shelters. All males >170 g were mature, the smallest male being 136 g. No mature females were found in the study area, and maturing females spanned a broad size range caught (275–3 600 g). Average size at spawning is probably between 1 500 and 2 500 g. Although there were no significant overall differences in mass between sexes (p > 0.05), the average mass of octopus in winter (766 g) was significantly smaller than in summer (1 161 g) and spring (964 g). Fluctuations in the average size of octopus tracked subsurface water temperature. The overall sex ratio was significantly biased towards males (0.6F:1.0M, p < 0.01), largely because fewer females were caught during spring and summer. Spawning likely occurs throughout the year. However, significantly higher (p < 0.01) female gonadal somatic indices of 0.52 and 0.46 found in spring and summer respectively (periods of warmer water in False Bay) may indicate peak spawning during those seasons.Keywords: maturation, morphometrics, Octopus vulgaris, population biology, sex ratio, spawning seasonAfrican Journal of Marine Science 2002, 24: 185–19
Environmental migrants, climate ‘refugees’ and sun-seeking expats
The question of how migration patterns will be influenced by environmental and climate change has received much attention within policy and academic circles. This focus can be explained in part by fears voiced by an alarmist group of migration scholars regarding uncontrolled population movements over country borders at the hands of a changing climate. This chapter explores the undercurrents driving widespread interest in the interaction between climate change and migration. In so doing, it explores how narratives around migration have been shaped by the use of certain terminology or ways to define, theorise, facilitate and problematise the movement of people. Current understanding of the interactions between the environment and human migration are characterised by a high degree of complexity and uncertainty. A wide range of methods and theoretical frameworks have thus been developed that seek to expand our understanding of its dynamics. Despite methodological and conceptual advances within the field, we propose that future research and policy must consider the loaded nature of language and the ways in which terms such as ‘climate change’ and ‘migration’ are interpreted. Care must be taken to ensure that the development of actions and policy initiatives truly serve to protect and benefit affected people, whether they are on the move, have arrived in a new destination, or are immobile and want but are unable to move
Entering the "foxhole": Partisan media priming and the application of racial justice in America
Can accessing a partisan media environment—irrespective of its content—change how Americans interpret and assess news? We examine this question by focusing on one of the most fraught issues in American society: racial justice. Although studies suggest that repeated exposure to right-leaning media messaging can amplify racial resentment, we leverage a pair of survey experiments to test whether merely seeing a conservative media masthead can make Whites render justice with racialized considerations. Results show that—even keeping the content of stories identical—entering a simulated right-leaning media environment significantly conditions racial attitudes. We find evidence of both anti-Black and pro-White biases that are activated when respondents consume information under the Fox News masthead. This study has important implications for understanding how partisan media priming shapes political views and the distinctive nature of racism in America
Measuring attitude towards Buddhism and Sikhism : internal consistency reliability for two new instruments
This paper describes and discusses the development and empirical properties of two new
24-item scales – one measuring attitude toward Buddhism and the other measuring attitude
toward Sikhism. The scale is designed to facilitate inter-faith comparisons within the
psychology of religion alongside the well-established Francis Scale of Attitude toward
Christianity. Data were obtained from a multi-religious sample of 369 school pupils aged
between 13 and 15 in London. Application of the two scales demonstrated that adolescents
had a more positive attitude to Buddhism than Sikhism. The findings confirm the reliability
of the scales and commend them for further use
The Relationship Between Mucosal Microbiota, Colitis, and Systemic Inflammation in Chronic Granulomatous Disorder
PURPOSE: Chronic granulomatous disorder (CGD) is a primary immunodeficiency which is frequently complicated by inflammatory colitis and is associated with systemic inflammation. Herein, we aimed to investigate the role of the microbiome in the pathogenesis of colitis and systemic inflammation. METHODS: We performed 16S rDNA sequencing on mucosal biopsy samples from each segment of 10 CGD patients’ colons and conducted compositional and functional pathway prediction analyses. RESULTS: The microbiota in samples from colitis patients demonstrated reduced taxonomic alpha-diversity compared to unaffected patients, even in apparently normal bowel segments. Functional pathway richness was similar between the colitic and non-colitic mucosa, although metabolic pathways involved in butyrate biosynthesis or utilization were enriched in patients with colitis and correlated positively with fecal calprotectin levels. One patient with very severe colitis was dominated by Enterococcus spp., while among other patients Bacteroides spp. abundance correlated with colitis severity measured by fecal calprotectin and an endoscopic severity score. In contrast, Blautia abundance is associated with low severity scores and mucosal health. Several taxa and functional pathways correlated with concentrations of inflammatory cytokines in blood but not with colitis severity. Notably, dividing patients into “high” and “low” systemic inflammation groups demonstrated clearer separation than on the basis of colitis status in beta-diversity analyses. CONCLUSION: The microbiome is abnormal in CGD-associated colitis and altered functional characteristics probably contribute to pathogenesis. Furthermore, the relationship between the mucosal microbiome and systemic inflammation, independent of colitis status, implies that the microbiome in CGD can influence the inflammatory phenotype of the condition
International Society of Sports Nutrition position stand: beta-alanine
Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the ISSN are as follows: 1) Four weeks of beta-alanine supplementation (4–6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; 2) Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; 3) The only reported side effect is paraesthesia (tingling), but studies indicate this can be attenuated by using divided lower doses (1.6 g) or using a sustained-release formula; 4) Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration; 5) Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; 6) Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4–6 g daily) and long enough (minimum 4 weeks); 7) More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 min in duration, and other health-related benefits associated with carnosine
A mathematical modelling study of an athlete's sprint time when towing a weighted sled
This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s12283-013-0114-2.This study used a mathematical model to examine the effects of the sled, the running surface, and the athlete on sprint time when towing a weighted sled. Simulations showed that ratio scaling is an appropriate method of normalising the weight of the sled for athletes of different body size. The relationship between sprint time and the weight of the sled was almost linear, as long as the sled was not excessively heavy. The athlete’s sprint time and rate of increase in sprint time were greater on running surfaces with a greater coefficient of friction, and on any given running surface an athlete with a greater power-to-weight ratio had a lower rate of increase in sprint time. The angle of the tow cord did not have a substantial effect on an athlete’s sprint time. This greater understanding should help coaches set the training intensity experienced by an athlete when performing a sled-towing exercise
Cardiac adaptations from 4 weeks of intensity-controlled vigorous exercise are lost after a similar period of detraining
Intensity‐controlled (relative to VO2max) treadmill exercise training in adult rats results in the activation and ensuing differentiation of endogenous c‐kitpos cardiac stem/progenitor cells (eCSCs) into newly formed cardiomyocytes and capillaries. Whether these training‐induced adaptations persist following detraining is undetermined. Twelve male Wistar rats (~230 g) were exercised at 80–85% of their VO2max for 30 min day−1, 4 days week−1 for 4 weeks (TR; n = 6), followed by 4 weeks of detraining (DTR; n = 6). Twelve untrained rats acted as controls (CTRL). Exercise training significantly enhanced VO2max (11.34 mL kg−1 min−1) and wet heart weight (29%) above CTRL (P < 0.05). Echocardiography revealed that exercise training increased LV mass (~32%), posterior and septal wall thickness (~15%), ejection fraction and fractional shortening (~10%) compared to CTRL (P < 0.05). Cardiomyocyte diameter (17.9 ± 0.1 μm vs. 14.9 ± 0.6 μm), newly formed (BrdUpos/Ki67pos) cardiomyocytes (7.2 ± 1.3%/1.9 ± 0.7% vs. 0.2 ± 0.1%/0.1 ± 0.1%), total cardiomyocyte number (45.6 ± 0.6 × 106 vs. 42.5 ± 0.4 × 106), c‐kitpos eCSC number (884 ± 112 per 106 cardiomyocytes vs. 482 ± 132 per 106 cardiomyocytes), and capillary density (4123 ± 227 per mm2 vs. 2117 ± 118 per mm2) were significantly greater in the LV of trained animals (P < 0.05) than CTRL. Detraining removed the stimulus for c‐kitpos eCSC activation (640 ± 98 per 106 cardiomyocytes) and resultant cardiomyocyte hyperplasia (0.4 ± 0.3% BrdUpos/0.2 ± 0.2% Ki67pos cardiomyocytes). Capillary density (3673 ± 374 per mm2) and total myocyte number (44.7 ± 0.5 × 106) remained elevated following detraining, but cardiomyocyte hypertrophy (15.0 ± 0.4 μm) was lost, resulting in a reduction of anatomical (wall thickness ~4%; LV mass ~10% and cardiac mass ~8%, above CTRL) and functional (EF & FS ~2% above CTRL) parameters gained through exercise training. These findings demonstrate that cardiac adaptations, produced by 4 weeks of intensity‐controlled exercise training are lost after a similar period of detraining
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