886 research outputs found
The effect of previous wingate performance using one body region on subsequent wingate performance using a different body region
The 30 second Wingate Anaerobic Test (WAnT) is the gold standard measure of anaerobic performance. The present investigation aimed to determine if a previous WAnT using one body region significantly affected a subsequent WAnT using a different body region. Twelve male university students (n = 12, 23 Β± 2 years, 84 Β± 16.1 kg, 178.5 Β± 7.4 cm) volunteered to complete two repeated WAnT protocols (either lower body WAnT followed by an upper body WAnTor vice versa) on two separate testing occasions. The upper body WAnT was conducted on a modified electromagnetically braked cycle ergometer using a flywheel braking force corresponding to 5% bodyweight. The lower body WAnT was conducted on an electronically braked cycle ergometer using a flywheel braking force corresponding to 7.5% bodyweight. Participants had a 1 minute rest period for transition between WAnTs. Data are reported as mean Β± standard deviation. No significant differences were identified in power indices for the lower body between 30 s WAnTs. When the upper body WAnT was performed 2nd, absolute peak power (p < 0.01), mean power (p < 0.001) and relative mean power (p < 0.001) were significantly lower compared to when the upper body WAnT was performed 1st. The value of maximum revolutions per minute was significantly lower (p < 0.001) when the upper body WAnT was performed after the lower body WAnT, compared to when it was performed 1st (193.3 Β± 11.4 1st vs 179.8 Β± 14.4 2nd). Previous upper body sprint exercise does not significantly affect lower body sprint exercise; however, previous lower body sprint exercise severely compromises subsequent upper body sprint performance
The role of bone marrow derived cells in cardiac repair
PhDCurrent pharmacological therapies fail to address the final end-point of cardiac
ischaemia β the death and dysfunction of cardiomyocytes. Advances in stem
cell biology have provided hope, for the first time, of addressing this underlying
pathology. The work performed here was designed to further understanding
of the mechanisms by which bone marrow derived cells improve damaged myocardium.
In situ hybridisation was used to detect sex chromosomes within ex-planted,
human, sex-mismatch hearts. Host derived cells were found at low frequency in
donor hearts, suggesting ongoing post-natal cardiac tissue repair.
Human mesenchymal stem cells were examined in vitro and in a rat model
of ischaemia-reperfusion injury. Cardiomyocytes were not formed when cultured
with either 5-azacytidine or ascorbic acid, and the cells failed to home to the ischaemic
heart or improve cardiac function.
In the same model, rat mononuclear cells significantly reduced infarct size
when administered immediately upon reperfusion. Cells were rarely identified
within the myocardium. No functional improvement was seen acutely, but at
seven days cardiac function had improved. The low frequency of cells retained
in the heart suggested that a process other than transdifferentiation accounted
for the observations.
Hence, evidence for paracrine actions was sought. In the same model, apoptosis
and necrosis in cardiomyocytes were found to be significantly reduced.
Western blots demonstrated activation of the reperfusion salvage kinase pathway,
analogous to that seen in ischaemic pre- and post-conditioning. Blocking
this pathway abolished the infarct size reduction. Global proteomic analysis confirmed
alterations in protein expression consistent with known cardioprotective
pathways.
In conclusion, endogenous myocardial repair processes are inadequate to
compensate for pathological insults. Supplementation with mononuclear cells in
an ischaemia-reperfusion model produced significant benefit to infarct size and
cardiac function. The mechanism of benefit appears to be induced by paracrine
effects activating pro-survival pathways.British Heart Foundatio
University-level Soccer Players Adopt a Unique βPacing Strategy'
Letter to the editor: We were interested to read the recent article by Mugglestone et al. [9], which examined high-speed running performances of university soccer players during the early stages of each half in competitive match-play. The data is a welcome addition to a small body of work examining the intra-match trends in soccer work rate, with particular reference to the half-time interval and its impact upon players' subsequent physical performances. In this letter we direct the authors to several relevant studies that were not considered in their article [1] [3] [11] [12]. We hope that by highlighting these research contributions to the authors and readership, interpretation of intra-match analysis trends can be undertaken with necessary due care and caution
Synthesis of Pyrimidines as Potential Tuberculosis Drugs
6-Aryl-9-substituted benzylpurines as antimycobacterial agents have been previously studied in our group.1-5 The structural activity relationship (SAR) of antimycobacterial purines is generally well understood5 (Figure 1, compound 1). We have decided, after exploring the SAR of intact purines to investigate the activity of pyrimidine analogs of 6-aryl-9-substituted benzylpurines antimycobacterial agents. Herein we discuss the synthesis of 6-aryl-4-substituted benzylpyrimidines (Figure 1, compound 2) and antimycobacterial activity of these compounds found to date
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