1,721,013 research outputs found
The effects of training on hormonal concentrations and physical performance of football referees
No full textAs no study has explored the impact of physical stress on hypothalamic-pituitary-gonadal axis hormones over a long period, the purpose of this study was to determine the effects of the football season period on plasma cortisol and testosterone concentrations and referee's physical performances. Physical tests and plasma cortisol and testosterone concentrations were assayed before the beginning of the training period, just after the training period, at the middle of the season, and at the end of the season, in 29 male football referees and 30 healthy control subjects. Results showed significant differences in hormone concentrations at the four-time points evaluated. Plasma cortisol increased during the first training period from 15.8 ± 3.8 to 21.7 ± 5.1 μg/dl (p < 0.001), then decreased during the season and at the end of it was 18.7 ± 2.4 μg/dl. Before the beginning of the training period, plasma testosterone concentration was 386.1 ± 58.8 ng/dl; after the training period, it increased to 572.2 ± 88.1 ng/dl (p < 0.001) and then returned to baseline levels at the end of the season. Between the start of the training period and the end of the season, significant differences were observed in physical performances of referees. Plasma cortisol and testosterone levels significantly (p < 0.0001 for both) correlated with Yo-Yo intermittent recovery test level 1 (YYIRT1) and maximal oxygen consumption (VO2max) at the end of the training period. In the middle season, plasma testosterone concentration only significantly (p < 0.0001) correlated with YYIRT1 and VO2max. These data underline the importance of set up training protocols that present the prospective to favor positive physiological adaptations
The effects of exercise training on lipid metabolism and coronary heart disease
Full text linkThe effects of exercise training on lipid metabolism and coronary heart disease. Am J Physiol Heart Circ Physiol 319: H76-H88, 2020. First published May 22, 2020; doi:10.1152/ajpheart.00708. 2019.-Blood lipoproteins are formed by various amounts of cholesterol (C), triglycerides (TGs), phospholipids, and apolipoproteins (Apos). ApoA1 is the major structural protein of high-density lipoprotein (HDL), accounting for ~70% of HDL protein, and mediates many of the antiatherogenic functions of HDL. Conversely, ApoB is the predominant low-density lipoprotein (LDL) Apo and is an indicator of circulating LDL, associated with higher coronary heart disease (CHD) risk. Thus, the ratio of ApoB to ApoA1 (ApoB/ApoA1) is used as a surrogate marker of the risk of CHD related to lipoproteins. Elevated or abnormal levels of lipids and/or lipoproteins in the blood are a significant CHD risk factor, and several studies support the idea that aerobic exercise decreases CHD risk by partially lowering serum TG and LDL-cholesterol (LDL-C) levels and increasing HDL-C levels. Exercise also exerts an effect on HDL-C maturation and composition and on reverse C transport from peripheral cells to the liver to favor its catabolism and excretion. This process prevents atherosclerosis, and several studies showed that exercise training increases heart lipid metabolism and protects against cardiovascular disease. In these and other ways, it more and more appears that regular exercise, nutrition, and strategies to modulate lipid profile should be viewed as an integrated whole. The purpose of this review is to assess the effects of endurance training on the nontraditional lipid biomarkers, including ApoB, ApoA1, and ApoB/ApoA1, in CHD risk
A novel monoclonal antibody to a plasmamembrane-located breast cancer antigen Interferes with the proliferation rate of cancerous cells in vitro
No full textThe effects of training on hormonal concentrations in young soccer players
Full text linkTo test the hypothesis that football training would be accompanied by physiological adaptations and hormonal changes, we analyzed the effects of a whole football season on physical fitness and hormonal concentrations in youth football players. Male football players (n = 29, age 16.51 ± 0.7 years) in a regional professional league and male healthy control subjects (n = 30, age 17.1 ± 1 years) participated to the study. Blood cortisol, testosterone, and growth hormone (hGH) concentrations were assayed before the beginning of the training period (T0), just after the training period (T1), at the middle of the season (T2), and at the end of the season (T3). In each period physical tests and anthropometric measurements were also performed. Results showed significant differences in basal values of cortisol, testosterone, and growth hormone (hGH) in the four time points evaluated (P < 0.01). In addition, the concentrations of hGH were higher in the soccer players group than in control subjects (P < 0.001). Between the start of the training period and the end of the football season significant differences were observed in the anthropometric characteristics and in the physical form of the football players. Furthermore, the hormonal status was significantly correlated with the indicators of the lower limb power (squat-jump [SqJ], and counter-movement-jump [CMJ]) and those of aerobic performance (Yo–Yo intermittent recovery test level 1 (YYIRT1) and maximal oxygen consumption (VO2max)).These data underscore the importance of establishing training protocols that present the potential to promote positive adaptations without, at the same time, provoking overtraining of young players
Referees' physical performance over a soccer season
Full text linkBackground: An important role of soccer referees is to apply the rules of the game by observing the match closely. Thus, referees have to undertake training to keep up with play and attain an optimal position when making critical decisions. We analyzed the variation of the soccer referee physical performance during official championship. Methods: The referees were classified into three groups according to ages (16–20 years; 21–29 years; 30–45 years) and physical fitness variations were studied at the start (T0), at the middle (T1) and at the end of the competitive season (T2). In each period, Yo–Yo intermittent recovery test level 1 (YYIRT1) and 40 m sprint test were performed and VO2max assessed. Finally, the referees’s rating (i.e. the mean of numerically quantification of the performances received during the season) was also evaluated. Results: The mean distance covered by the referees during the YYIRT1 test increased significantly from T0 to T1 and T2, and from T1 to T2, in all age groups, with a higher effect observed for group 16–20 years in all testing periods. This group significantly improved YYIR1 performance and VO2max at T1and T2. Referee ages correlated with differences (Δ) in running speed test (40 m sprint test), of YYIRT1 and VO2max. Finally, the referees’ rating, based upon training, experience, performance and fitness assigned by qualified officials, ranged from 8.20 to 8.65. A positive correlation was found between the excellent rating and younger age (p = 0.015 by Chi-square test χ = 8.6). Conclusions: The young referees performed better physical performances than adult referees and obtained better assessments by qualified officials
TGF-β1 activates RSC96 Schwann cells migration and invasion through MMP-2 and MMP-9 activities
No full textFollowing peripheral nerve injury, remnant Schwann cells adopt a migratory phenotype and remodel the extracellular matrix allowing axonal regrowth. Although much evidence has demonstrated that TGF-β1 promotes glioma cell motility and induces the expression of extracellular matrix proteins, the effects of TGF-β1 on Schwann cell migration has not yet been studied. We therefore investigated the cellular effects and the signal transduction pathways evoked by TGF-β1 in rattus norvegicus neuronal Schwann RSC96 cell. TGF-β1 significantly increased migration and invasion of Schwann cells assessed by the wound-healing assay and by cell invasion assay. TGF-β1-enhanced migration/invasion was blocked by inhibition of MMP-2 and MMP-9. Consistently, by real-time and western blot analyses, we demonstrated that TGF-β1 increased MMP-2 and MMP-9 mRNA and protein levels. TGF-β1 also increased MMPs activities in cell growth medium, as shown by gelatin zymography. The selective TGF-β Type I receptor inhibitor SB431542 completely abrogated any effects by TGF-β1. Indeed, TGF-β1 Type I receptor activation provoked the cytosol-to-nucleus translocation of SMAD2 and SMAD3. SMAD2 knockdown by siRNA blocked MMP-2 induction and cell migration/invasion due to TGF-β1. TGF-β1 also provoked phosphorylation of MAPKs extracellular regulated kinase 1/2 and JNK1/2. Both MAPKs were upstream to p65/NF-kB inasmuch as both MAPKs’ inhibitors PD98059 and SP600125 or their down-regulation by siRNA significantly blocked the TGF-β1-induced nuclear translocation of p65/NF-kB. In addition, p65/NF-κB siRNA knockdown inhibited the effects of TGF-β1 on both MMP-9 and cell migration/invasion. We conclude that TGF-β1 controls RSC96 Schwann cell migration and invasion through MMP-2 and MMP-9 activities. MMP-2 is controlled by SMAD2 whilst MMP-9 is controlled via an ERK1/2-JNK1/2-NF-κB dependent pathway. (Figure presented.)
Is mitochondrial DNA profiling predictive for athletic performance?
No full textMitochondrial DNA encodes some proteins of the oxidative phosphorylation enzymatic complex, playing an important role in aerobic ATP production; therefore, it can contribute to the ability to respond to endurance exercise training. The accumulation of mitochondrial mutations and the migratory processes of populations have given a great contribution to the development of haplogroups with a different distribution in the world. Several studies have shown the important role of gene polymorphisms in aerobic performance. In this review, some mitochondrial haplogroups and multiple rare alleles were taken into consideration and could be linked to the athlete's physical performance of different ethnic groups
Human larynx expresses isoforms of the oestrogen receptor.
No full textCommercially available enzyme immunoassays (EIAs) were used for oestrogen (ER) and progesterone (PR) receptor determination in the cytosol fraction of 118 human larynx cancer specimens and in the corresponding histologically proven non-malignant tissues. Fifty-one ER positive cancerous samples had corresponding non-cancerous tissues also expressing the receptor. A high resolution isoelectric focusing (IEF) technique followed by immunoblotting with the H222 anti-ER monoclonal antibody was used to evaluate the presence of ER isoforms in the 51 ER positive human larynx cancer specimens and in their corresponding non-malignant tissues. In both tissues, four ER isoforms were detected, with isoelectric points (pI) similar to those obtained in breast and endometrium carcinomas (6.1, 6.3, 6.6 and 6.8). A significant difference in the expression of ER isoforms between cancerous and non-cancerous tissue was found; precisely, the 94.1% of the ER positive non-malignant specimens co-expressed the four isoforms while they were detected in only the 35.5% of the malignant specimens (P < 0.0001 by Fisher's exact test). In larynx cancer, the concentration values of ER and PR did not correlate, nevertheless tumours co-expressing the four ER isoforms had PR levels significantly higher than those which did not (P = 0.02 by Mann-Whitney Wilcoxon sum rank test). To investigate the possibility that the isoforms of the monomeric 4S form of the ER (those with pI 6.3, 6.6, and 6.8) could dimerise, a cold agarose gel electrophoresis technique was used on IEF-separated ER isoforms. In summary, the evidence shows that all the isoforms are able to form homodimers and that the isoforms at pI 6.3 and 6.8 are able to dimerise with that at pI 6.6 but, under the same experimental conditions, they do not form the 6.3/6.8 heterodimer. It was concluded that: (1) the four isoforms of the ER are co-expressed by the non-malignant human larynx and the cancer loses the capacity to express some of them; (2) the complete complement of ER isoforms (all four) is needed for PR expression; (3) the monomeric 4S isoform with pI 6.6 has the capacity to form homo- and heterodimers, while the remaining two are only able to homodimerise
The regulation of fat metabolism during aerobic exercise
Full text linkSince the lipid profile is altered by physical activity, the study of lipid metabolism is a remarkable element in understanding if and how physical activity affects the health of both professional athletes and sedentary subjects. Although not fully defined, it has become clear that resistance exercise uses fat as an energy source. The fatty acid oxidation rate is the result of the following processes: (a) triglycerides lipolysis, most abundant in fat adipocytes and intramuscular triacylglycerol (IMTG) stores, (b) fatty acid transport from blood plasma to muscle sarcoplasm, (c) availability and hydrolysis rate of intramuscular triglycerides, and (d) transport of fatty acids through the mitochondrial membrane. In this review, we report some studies concerning the relationship between exercise and the aforementioned processes also in light of hormonal controls and molecular regulations within fat and skeletal muscle cells
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