1,721,308 research outputs found
Compartmentalization of signaling by vesicular trafficking: a shared building design for the immune synapse and the primary cilium
No full textAccumulating evidence underscores the immune synapse (IS) of naive T cells as a site of intense vesicular trafficking. At variance with helper and cytolytic effectors, which use the IS as a secretory platform to deliver cytokines and/or lytic granules to their cellular targets, this process is exploited by naive T cells as a means to regulate the assembly and maintenance of the IS, on which productive signaling and cell activation crucially depend. We have recently identified a role of the intraflagellar transport (IFT) system, which is responsible for the assembly of the primary cilium, in the non-ciliated T-cell, where it controls IS assembly by promoting polarized T-cell receptor recycling. This unexpected finding not only provides new insight into the mechanisms of IS assembly but also strongly supports the notion that the IS and the primary cilium, which are both characterized by a specialized membrane domain highly enriched in receptors and signaling mediators, share architectural similarities and are homologous structures. Here, we review our current understanding of vesicular trafficking in the regulation of the assembly and maintenance of the naive T-cell IS and the primary cilium, with a focus on the IFT system
VO2max, ventilatory and anaerobic thresholds in rhythmic gymnasts and young female dancers
No full textBackground. This study examines the fitness level of a rhythmic gymnasts group and a young female classical dancers group. Methods. Aerobic power (V̇O2max), individual ventilatory (IVT) and anaerobic thresholds (IAT) were assessed in 12 elite rhythmic gymnasts, eight elite ballet dancers and 12 sedentary female subjects in the same age range (13-16 yrs). The V̇O2max, IVT and TAT were assessed during a continuous incremental running treadmill test. Results. At IVT and IAT the V̇O2max expressed in ml·kg-1·min-1 was significantly different between the three groups of subjects. The highest values were found in gymnasts (30.8±2.6 for IVT and 43.8±3.5 for IAT) followed by the values of dancers (21.7±2.8 for IVT and 30.5±3.1 for IAT) and controls (15.6±2.0 for IVT and 20.6±1.7 for IAT). When the V̇O2max was expressed in percent of V̇O2max, the values at IAT were significantly different between all groups (gymnasts: 84.9±0.7; dancers: 64.0±4.1; controls: 59.7±2.4) while at IVT no difference was found between dancers and controls (45.6±4.1 and 45.2±16, respectively). At maximal effort V̇O2 was significantly higher both in gymnasts and dancers (51.7±4.4 and 47.5±3.0 ml·kg-1·min-1, respectively), than in controls (34.5±2.5 ml·kg-1·min-1). Conclusions. Although V̇O2max was similar between gymnasts and dancers, V̇O2 values at NT and IAT were able to discriminate the higher level of fitness in gymnasts with respect to dancers
A simple method for individual anaerobic threshold as predictor of max lactate steady state
No full textBackground: The individual anaerobic threshold (IAT) is defined (18) as the highest metabolic rate where blood lactate (La) concentrations are maintained at a steady-state during prolonged exercise. Stegmann et al.'s (18) method to detect IAT, using La-performance relationship during incremental graded exercise, is based on the assumption that La is in relatively steady state by the end of each 3-min stage of work rate. However, at the end of a 3-min stage, an La steady state (Lass) is not reached (13). Purpose: The present study was designed to investigate whether the IAT should be determined by attributing La value to the antecedent stage (IAT(a)) or to the same stage of its measurement (IAT(m)), then to verify whether this IAT would be a valid indicator of the max Lass during prolonged exercise. Methods: Forty-one athletes (21 male and 20 female), regularly involved in different physical training, performed three exercise tests on treadmill. The first one was a 3-min stage incremental test to detect the IAT(a) and IAT(m). The other two tests were 30-min prolonged tests at the IAT(a) and IAT(m) workload. Lass were present in IAT(a) intensity (about 4.0 mmol · L-1) both in male and female athletes, whereas at IAT(m) intensity a Lass was not present and a premature break-off occurred in some cases. Discussion: This protocol can be useful for practical use because: 1) the method of choosing the anaerobic threshold is easy to apply; 2) it does not require to reach the maximal effort; and 3) although in some cases the IAT(a) could probably underestimate the workload of max Lass, the IAT(a) can be regarded as guideline to define the intensity of endurance training
Falcioni L, Gallotta MC, Baldari C, Cardinali L, Campanella M, Ferrari D, Guidetti L, Meucci M. Influence of training status on cardiac and vascular functioning in young recreational and competitive male rowers. Frontiers in Pediatrics, section Pediatric Cardiology
No full textIntroduction: The aim of the study was to investigate the influence of training
status on cardiovascular function in young male recreational and competitive
rowers.
Methods: Ejection duration in percentage to the heart rate period (ED%),
subendocardial viability ratio (SEVR), augmentation index at 75 bpm (AIx75) and
carotid to femoral pulse wave velocity (cf-PWV) of competitive rowers (CR) (age
17.6 ± 4.1 years), recreational rowers (RR) (age 16.7 ± 2.70 years) and athletes
practicing other recreational sports (ORS) (age 15.3 ± 1.4 years) were assessed.
Results: ED% was lower in CR compared to ORS (31.9 ± 3.9% vs. 38.4 ± 4.8%; p =
0.026) and cf-PWV was higher in CR compared to ORS (5.5 ± 1.0 m/s vs. 4.7 ±
0.5 m/s; p = 0.032). SEVR was higher in CR compared to RR and ORS (165.8 ±
33.7% vs. 127.4 ± 30.4% and 128.3 ± 27.8%; p = 0.022) and AIx75 was lower in CR
compared to RR and ORS (−15.7 ± 8.6% vs. 1.2 ± 9.9% and 1.5 ± 9.1; p = 0.001).
Discussion: Healthy, young competitive male rowers reported higher myocardial
performance and better cardiovascular health than recreational athletes.
Interpretations of cf-PWV in competitive rowers should be performed alongside
other cardiovascular indicators
About creation and other misnomers
No full textSloppy and careless use of words abound in common language. But scientists should adhere to precise and accurate language in their communication with peers and the public
Motor proficiency and physical activity in preschool girls: a preliminary study
No full textPhysical activity during preschool age promotes sports learning and the acquisition of fundamental and complex movement skills. The aim of this study was to evaluate the impact of three different four-month physical and/or pre-sport activity programmes on preschool children’s motor proficiency. Twenty-five girls, aged between four and six years, were involved in the study, 10 practising physical activity, six practising dance (classical), nine practising swimming. Girls’ motor proficiency was assessed before and after the intervention period by means of the BOT-2 Bruininks–Oseretsky Test of Motor Proficiency-Short Form (BOT-2 SF). Differential effects of interventions emerged in fine manual control and coordination and in running speed and agility. A playful and highly varied physical activity intervention conducted by a specialized teacher was more effective for the development of preschool girls’ motor proficiency
Lifestyle and Osteoporosis Risk in Men (Physical Activity, Diet, Alcohol Abuse)
No full textMale osteoporosis is a health problem of multifactorial origin. Bone mineral density evaluation (BMD) by X-ray densitometry allows diagnosis, while stratification of risk fracture is usually done through useful diagnostic tools (i.e., FRAXc). The risk of osteoporotic fracture results from a combination of modifiable and unmodifiable factors. Lifestyle factors are the modifiable factors that can greatly impact on overall health and well-being, including bone health. Many lifestyle factors such as physical activity, diet, alcohol abuse, and smoking can have substantial effects on bone metabolism. Nowadays, the crucial role that lifestyle factors play in the development of male osteoporosis has generated a growing interest in this field of study. Male osteoporosis prevention (or non-pharmacological intervention) should be based on the elimination of specific modifiable risk factors (alcohol abuse, smoking, environmental risk factors for falls, etc.) by means of regular physical activity and an adequate nutritional supply of calcium and vitamin D. Non-pharmacological interventions for the prevention and treatment of osteoporosis are recommended for all subjects
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