FbsA, a fibrinogen-binding protein from Streptococcus agalactiae, mediates platelet aggregation

The bacterium Streptococcus agalactiae is an etiologic agent in the pathogenesis of endocarditis in humans. FbsA, a fibrinogen-binding protein produced by this pathogen, is considered an important virulence factor. In the present study we provide evidence that S agalactiae clinical isolates bearing FbsA attach to fibrinogen and elicit a fibrinogen-dependent aggregation of platelets. Mutants of S agalactiae lacking the fbsA gene lost the ability to attach to fibrinogen and to aggregate platelets. Plasmid-mediated expression of fbsA restored the capability for fibrinogen binding and platelet aggregation in S agalactiae fbsA mutants, and allowed Lactococcus lactis to interact with fibrinogen and to aggregate human platelets. Moreover, a monoclonal anti-FbsA antibody inhibited bacterial adherence to fibrinogen and S agalactiae-induced platelet aggregation. Platelet aggregation was inhibited by aspirin, prostaglandin E(1,) the peptide RGDS, and the antibody abciximab, demonstrating the specificity of platelet aggregation by S agalactiae and indicating an involvement of integrin glycoprotein IIb/IIIa in the induction of platelet aggregation. Aggregation was also dependent on anti-FbsA IgG and could be inhibited by an antibody against the platelet FcgammaRIIA receptor. These findings indicate that FbsA is a crucial factor in S agalactiae-induced platelet aggregation and may therefore play an important role in S agalactiae-induced endocarditis

Recent Advances in Ultra-High-Speed Optical Signal Processing

We review recent advances in the optical signal processing of ultra-high-speed serial data signals up to 1.28 Tbit/s, with focus on applications of time-domain optical Fourier transformation. Experimental methods for the generation of symbol rates up to 1.28 Tbaud are also described.</p

Independent and Combined Effects of Dietary Weight Loss and Exercise on Leukocyte Telomere Length in Postmenopausal Women

Objective: Investigate the effects of 12 months of dietary weight loss and/or aerobic exercise on leukocyte telomere length in postmenopausal women. Design and Methods 439 overweight or obese women (50–75 y) were randomized to: i) dietary weight loss (N=118); ii) aerobic exercise (N=117), iii) diet + exercise (N=117), or iv) control (N=87). The diet intervention was a group-based program with a 10% weight loss goal. The exercise intervention was 45 mins/day, 5 days/week of moderate-to-vigorous aerobic activity. Fasting blood samples were taken at baseline and 12 months. DNA was extracted from isolated leukocytes and telomere length was measured by quantitative-polymerase chain reaction (qPCR). Mean changes were compared between groups (intent-to-treat) using generalized estimating equations. Results: Baseline telomere length was inversely associated with age (r=−0.12 p<0.01) and positively associated with maximal oxygen uptake (r=0.11, p=0.03), but not with BMI or %body fat. Change in telomere length was inversely correlated with baseline telomere length (r=−0.47, p<0.0001). No significant difference in leukocyte telomere length was detected in any intervention group compared to controls, nor was the magnitude of weight loss associated with telomere length at 12 months. Conclusions: Twelve-months of dietary weight loss and exercise did not change telomere length in postmenopausal women

Earliest Triassic microbialites in the South China Block and other areas; controls on their growth and distribution

Earliest Triassic microbialites (ETMs) and inorganic carbonate crystal fans formed after the end-Permian mass extinction (ca. 251.4 Ma) within the basal Triassic Hindeodus parvus conodont zone. ETMs are distinguished from rarer, and more regional, subsequent Triassic microbialites. Large differences in ETMs between northern and southern areas of the South China block suggest geographic provinces, and ETMs are most abundant throughout the equatorial Tethys Ocean with further geographic variation. ETMs occur in shallow-marine shelves in a superanoxic stratified ocean and form the only widespread Phanerozoic microbialites with structures similar to those of the Cambro-Ordovician, and briefly after the latest Ordovician, Late Silurian and Late Devonian extinctions. ETMs disappeared long before the mid-Triassic biotic recovery, but it is not clear why, if they are interpreted as disaster taxa. In general, ETM occurrence suggests that microbially mediated calcification occurred where upwelled carbonate-rich anoxic waters mixed with warm aerated surface waters, forming regional dysoxia, so that extreme carbonate supersaturation and dysoxic conditions were both required for their growth. Long-term oceanic and atmospheric changes may have contributed to a trigger for ETM formation. In equatorial western Pangea, the earliest microbialites are late Early Triassic, but it is possible that ETMs could exist in western Pangea, if well-preserved earliest Triassic facies are discovered in future work

Effects of a twelve-week exercise intervention on subsequent compensatory behaviours in adolescent girls: an exploratory study

This is an accepted manuscript of an article published by Human Kinetics Publishers Inc. in Pediatric Exercise Science on 19/07/2019, available online: https://doi.org/10.1123/pes.2019-0012 The accepted version of the publication may differ from the final published version.Purpose: Chronic exercise programmes can induce adaptive compensatory behavioural responses through increased energy intake (EI) and/or decreased free-living physical activity in adults. These responses can negate the benefits of an exercise-induced energy deficit; however, it is unclear whether young people experience similar responses. This study examined whether exercise-induced compensation occurs in adolescent girls. Methods: Twenty-three adolescent girls, heterogeneous for weight status, completed the study. Eleven, 13-year-old adolescent girls completed a twelve-week supervised exercise intervention (EX). Twelve body size matched girls comprised the non-exercise control group (CON). Body composition, EI, free-living energy expenditure (EE) and peak oxygen uptake (V ̇O_2) were measured repeatedly over the intervention. Results: Laboratory EI (EX: 9027, 9610, 9243 kJd-1 and CON: 9953, 9770, 10052 kJd-1 at 0, 12 and 18 weeks respectively) (ES = 0.26, P = 0.46) and free living EI (EX: 7288, 6412, 5273, 4916 kJd-1 and CON: 7227, 7128, 6470, 6337 kJd-1 at 0, 6, 12 and 18 weeks respectively) (ES ≤ 0.26, P = 0.90) did not change significantly over time and were similar between groups across the duration of the study. Free-living EE was higher in EX than CON (13295 vs. 12115 kJd-1, ES ≥ 0.88, P ≥ 0.16), but no significant condition by time interactions were observed (P ≥ 0.17). Conclusion: The current findings indicate that compensatory changes in EI and EE behaviours did not occur at a group level within a small cohort of adolescent girls. However, analysis at the individual level highlights large inter-individual variability in behaviours, which suggest a larger study may be prudent to extend this initial exploratory research

No reduction in C-reactive protein following a 12-month randomized controlled trial of exercise in men and women.

Low-grade systemic inflammation is suggested to play a role in the development of several chronic diseases including cancer. Higher levels of physical activity and lower adiposity have been associated with reduced levels of markers of systemic inflammation, such as C-reactive protein (CRP); however, reductions in CRP have not been observed consistently in randomized controlled trials of exercise. Purpose: To examine the effect of a 12-month aerobic exercise intervention on CRP levels in men and women. Methods: 102 men and 100 women, sedentary and aged 40-75 years, mean BMI of 29.9 and 28.7 kg/m2, respectively, were randomly assigned to a 12-month moderate-to-vigorous aerobic exercise intervention (6 d/wk, 60 min/d, 60-85% maximum heart rate) or control group. Fasting blood samples were collected at baseline and at 12-months. CRP levels were measured by high-sensitivity latex-enhanced nephelometry. Results: At baseline, CRP was 1.16 mg/L and 2.11 for men and women, respectively, and CRP was correlated with percent body fat (r=0.48, p ≤0.001), BMI (r=0.37, p ≤0.001) and aerobic fitness (r=-0.49, p ≤0.001). No intervention effects were observed for CRP in men or women, or when stratified by baseline BMI (< 30 kg/m2 vs. ≥ 30 kg/m2) , baseline CRP (< 3 mg/L vs. ≥ 3 mg/L) or change in body weight, body composition or aerobic fitness. Conclusion: A 12 month moderate-to-vigorous aerobic exercise intervention did not affect CRP levels in previously sedentary men or women with average-risk CRP values at baseline

Walking ability during daily life in patients with osteoarthritis of the knee or the hip and lumbar spinal stenosis: a cross sectional study

<p>Abstract</p> <p>Background</p> <p>Degenerative musculoskeletal disorders are among the most frequent diseases occurring in adulthood, often impairing patients' functional mobility and physical activity. The aim of the present study was to investigate and compare the impact of three frequent degenerative musculoskeletal disorders -- knee osteoarthritis (knee OA), hip osteoarthritis (hip OA) and lumbar spinal stenosis (LSS) -- on patients' walking ability.</p> <p>Methods</p> <p>The study included 120 participants, with 30 in each patient group and 30 healthy control individuals. A uniaxial accelerometer, the StepWatch™ Activity Monitor (Orthocare Innovations, Seattle, Washington, USA), was used to determine the volume (number of gait cycles per day) and intensity (gait cycles per minute) of walking ability. Non-parametric testing was used for all statistical analyses.</p> <p>Results</p> <p>Both the volume and the intensity of walking ability were significantly lower among the patients in comparison with the healthy control individuals (p < 0.001). Patients with LSS spent 0.4 (IQR 2.8) min/day doing moderately intense walking (>50 gait cycles/min), which was significantly lower in comparison with patients with knee and hip OA at 2.5 (IQR 4.4) and 3.4 (IQR 16.1) min/day, respectively (p < 0.001). No correlations between demographic or anthropometric data and walking ability were found. No technical problems or measuring errors occurred with any of the measurements.</p> <p>Conclusions</p> <p>Patients with degenerative musculoskeletal disorders suffer limitations in their walking ability. Objective assessment of walking ability appeared to be an easy and feasible tool for measuring such limitations as it provides baseline data and objective information that are more precise than the patients' own subjective estimates. In everyday practice, objective activity assessment can provide feedback for clinicians regarding patients' performance during everyday life and the extent to which this confirms the results of clinical investigations. The method can also be used as a way of encouraging patients to develop a more active lifestyle.</p

A high fat breakfast attenuates the suppression of appetite and acylated ghrelin during exercise at simulated altitude.

High-altitude exposure induces a negative energy balance by increasing resting energy expenditure and decreasing energy intake. This diminished energy intake is likely caused by altitude-induced anorexia and can have detrimental effects for those travelling to high-altitude. We aimed to investigate whether altering the macronutrient composition of breakfast could attenuate altitude-induced anorexia and augment energy intake at high-altitude. Twelve healthy men (aged 26 (8) years, body mass index 23.9 (2.7) kg·m(-2)) completed two, 305min experimental trials at 4300m simulated altitude (~11.7% O2). After an overnight fast, participants entered a normobaric hypoxic chamber and rested for one hour, before receiving either a high fat (HF; 60% fat, 25% carbohydrate) or an isocaloric high carbohydrate (HC; 60% carbohydrate, 25% fat) breakfast. One hour after breakfast, participants performed 60min of treadmill walking at 50% of relative V̇O2max. An ad-libitum buffet meal was consumed 1h 30min after exercise. Appetite perceptions, blood samples and substrate oxidation rates were measured throughout. A significantly higher area under the curve for composite appetite score was observed during exercise in HF (40 (12) mm·h(-1)) compared with HC (30 (17) mm·h(-1), P=0.036). During exercise, lower insulin concentrations (P=0.013) and elevated acylated ghrelin concentrations (P=0.048) were observed in HF compared with HC. After exercise there was no significant difference in composite appetite score (P=0.356), acylated ghrelin (P=0.229) or insulin (P=0.513) between conditions. Energy intake at the buffet did not significantly differ between conditions (P=0.384). A HF breakfast attenuated appetite suppression during exercise at 4300m simulated altitude, however ad-libitum energy intake did not increase