KINETIC COMPARISON OF THE SPRINT STARTS BETWEEN YOUTH AND SENIOR ELITE ATHLETES

The purpose of this study was to identify differences in force, impulse and power characteristics in block starts and first two contacts between youth academy (n=20) and elite senior male sprinters (n=17). Senior sprinters were significantly faster out of the blocks with a horizontal velocity of 3.35m/s ±0.15 compared to 3.14 ±0.16m/s, leading to 10m times of 1.64±0.045s and 1.706±0.06s respectively. Force application time of the arms, rear leg and front leg were significantly lower in the senior athletes (all

The Post-Apoptotic Fate of RNAs Identified Through High-Throughput Sequencing of Human Hair

The hair of all mammals consists of terminally differentiated cells that undergo a specialized form of apoptosis called cornification. While DNA is destroyed during cornification, the extent to which RNA is lost is unknown. Here we find that multiple types of RNA are incompletely degraded after hair shaft formation in both mouse and human. Notably, mRNAs and short regulatory microRNAs (miRNAs) are stable in the hair as far as 10 cm from the scalp. To better characterize the post-apoptotic RNAs that escape degradation in the hair, we performed sequencing (RNA-seq) on RNA isolated from hair shafts pooled from several individuals. This hair shaft RNA library, which encompasses different hair types, genders, and populations, revealed 7,193 mRNAs, 449 miRNAs and thousands of unannotated transcripts that remain in the post-apoptotic hair. A comparison of the hair shaft RNA library to that of viable keratinocytes revealed surprisingly similar patterns of gene coverage and indicates that degradation of RNA is highly inefficient during apoptosis of hair lineages. The generation of a hair shaft RNA library could be used as months of accumulated transcriptional history useful for retrospective detection of disease, drug response and environmental exposure

Hemodynamic responses are reduced with aerobic compared with resistance blood flow restriction exercise

The hemodynamics of light-load exercise with an applied blood-flow restriction (BFR) have not been extensively compared between light-intensity, BFR, and high-intensity forms of both resistance and aerobic exercise in the same participant population. Therefore, the purpose of this study was to use a randomized crossover design to examine the hemodynamic responses to resistance and aerobic BFR exercise in comparison with a common high-intensity and light-intensity non-BFR exercise. On separate occasions participants completed a leg-press (resistance) or treadmill (aerobic) trial. Each trial comprised a light-intensity bout (LI) followed by a light-intensity bout with BFR (80% resting systolic blood pressure (LI+BFR)), then a high-intensity bout (HI). To characterize the hemodynamic response, measures of cardiac output, stroke volume, heart rate and blood pressure were taken at baseline and exercise for each bout. Exercising hemodynamics for leg-press LI+BFR most often resembled those for HI and were greater than LI (e.g. for systolic blood pressure LI+BFR = 152 ± 3 mmHg; HI = 153 ± 3; LI = 143 ± 3 P < 0.05). However, exercising hemodynamics for treadmill LI+BFR most often resembled those for LI and were lower than HI (e.g. for systolic pressure LI+BFR = 124 ± 2 mmHg; LI = 123 ± 2; HI = 140 ± 3 P < 0.05). In conclusion, the hemodynamic response for light aerobic (walking) BFR exercise suggests this mode of BFR exercise may be preferential for chronic use to develop muscle size and strength, and other health benefits in certain clinical populations that are contraindicated to heavy-load resistance exercise

Muscular Adaptations to Whole Body Blood Flow Restriction Training and Detraining

Resistance training with blood flow restriction is typically performed during single exercises for the lower- or upper-body, which may not replicate real world programming. The present study examined the change in muscle strength and mass in a young healthy population during an 8-week whole body resistance training program, as well as monitoring these adaptations following a 4-week detraining period. Thirty-nine participants (27 males, 12 females) were allocated into four groups: blood flow restriction training (BFR-T); moderate-heavy load training (HL-T), light-load training (LL-T) or a non-exercise control (CON). Testing measurements were taken at Baseline, during mid-point of training (week 4), end of training (week 8) and following four weeks of detraining (week 12) and included anthropometrics, body composition, muscle thickness (MTH) at seven sites, and maximal dynamic strength (1RM) for six resistance exercises. Whole body resistance training with BFR significantly improved lower- and upper-body strength (overall; 11% increase in total tonnage), however, this was similar to LL-T (12%), but both groups were lower in comparison with HL-T (21%) and all groups greater than CON. Some markers of body composition (e.g., lean mass) and MTH significantly increased over the course of the 8-week training period, but these were similar across all groups. Following detraining, whole body strength remained significantly elevated for both BFR-T (6%) and HL-T (14%), but only the HL-T group remained higher than all other groups. Overall, whole body resistance training with blood flow restriction was shown to be an effective training mode to increase muscular strength and mass. However, traditional moderate-heavy load resistance training resulted in greater adaptations in muscle strength and mass as well as higher levels of strength maintenance following detraining

MGMT promoter methylation testing to predict overall survival in people with glioblastoma treated with temozolomide: a comprehensive meta-analysis based on a Cochrane Systematic Review

BACKGROUND: The DNA repair protein O6 methylguanine-DNA methyltransferase (MGMT) causes resistance of tumour cells to alkylating agents. It is a predictive biomarker in high grade gliomas treated with temozolomide, however there is no consensus on which test method, methylation sites, and cut-off values to use. METHODS: We performed a Cochrane Review to examine studies using different techniques to measure MGMT and predict survival in glioblastoma patients treated with temozolomide. Eligible longitudinal studies included adults with glioblastoma treated with temozolomide with or without radiotherapy, or surgery; where MGMT status was determined in tumour tissue, and assessed by one or more technique; and where overall survival was an outcome parameter, with sufficient information to estimate hazard ratios. Two or more methods were compared in 32 independent cohorts with 3474 patients. RESULTS: Methylation-specific PCR (MSP) and pyrosequencing (PSQ) techniques were more prognostic than immunohistochemistry for MGMT protein, and PSQ is a slightly better predictor than MSP. CONCLUSIONS: We cannot draw strong conclusions about use of frozen tissue versus formalin-fixed paraffin embedded in MSP and PSQ. Also, our meta-analysis does not provide strong evidence about the best CpG sites or threshold. MSP has been studied mainly for CpG sites 76-80 and 84-87 and Pyrosequencing at CpG sites ranging from 72 to 95. A cut-off threshold of 9% for CpG sites 74-78 performed better than higher thresholds of 28% or 29% in two of three good-quality studies. 190 studies were identified presenting hazard ratios from survival analysis in patients in which MGMT methylation was measured by one technique only

MGMT promoter methylation testing to predict overall survival in people with glioblastoma treated with temozolomide:a comprehensive meta-analysis based on a Cochrane Review

BACKGROUND: The DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) causes resistance of tumor cells to alkylating agents. It is a predictive biomarker in high-grade gliomas treated with temozolomide, however, there is no consensus on which test method, methylation sites, and cutoff values to use. METHODS: We performed a Cochrane Review to examine studies using different techniques to measure MGMT and predict survival in glioblastoma patients treated with temozolomide. Eligible longitudinal studies included (i) adults with glioblastoma treated with temozolomide with or without radiotherapy, or surgery; (ii) where MGMT status was determined in tumor tissue, and assessed by 1 or more technique; and (iii) where overall survival was an outcome parameter, with sufficient information to estimate hazard ratios (HRs). Two or more methods were compared in 32 independent cohorts with 3474 patients. RESULTS: Methylation-specific PCR (MSP) and pyrosequencing (PSQ) techniques were more prognostic than immunohistochemistry for MGMT protein, and PSQ is a slightly better predictor than MSP. CONCLUSIONS: We cannot draw strong conclusions about use of frozen tissue vs formalin-fixed paraffin-embedded in MSP and PSQ. Also, our meta-analysis does not provide strong evidence about the best CpG sites or threshold. MSP has been studied mainly for CpG sites 76-80 and 84-87 and PSQ at CpG sites ranging from 72 to 95. A cutoff threshold of 9% for CpG sites 74-78 performed better than higher thresholds of 28% or 29% in 2 of the 3 good-quality studies. About 190 studies were identified presenting HRs from survival analysis in patients in which MGMT methylation was measured by 1 technique only

Probing the Substellar Regime with SIRTF

One of the main scientific drivers of the Space InfraRed Telescope Facility (SIRTF) is the search for brown dwarfs and extrasolar superplanets. We discuss observational strategies for identification of these objects, and conclude that an optimal strategy is a wide IRAC survey (18 deg$^2$) with a 5 $\sigma$ sensitivity of 3.9 $\mu$Jy in channel 2 (M$\sim19.1^m$). For this sensitivity, we provide estimates of the number of low mass brown dwarfs and isolated planets detected per square degree for power-law mass functions with $\alpha$=1.5, and 1.0. Shallower surveys covering a larger area are inefficient because of large overheads and detector noise. Deeper surveys covering a smaller area become more and more affected by crowding with galaxies. A survey like the one that we propose would determine the field mass function down to a few Jupiter masses through the identification of a large sample of brown dwarfs and isolated planets. The proposed SIRTF survey would also allow the first detection of ultracool substellar objects with temperatures between 700 K and 200 K. The cooling curves of substellar objects with masses less than 20 Jupiters imply that they should spend most of their lifetimes at temperatures below 700 K. Preliminary models indicate that their atmospheres could be dominated by water clouds, which would diminish their optical and near-infrared fluxes. The properties of those objects are still completely unexplored.Comment: 7 pages, 6 figures, submitted to PAS