Genetic and environmental influences on oxidative damage assessed in elderly Danish twins

Previous studies have shown an association between oxidative stress and various diseases in humans including cancer, cardiovascular disease, diabetes, and chronic respiratory disease. To what extents this damage is determined by genetic and environmental factors is unknown. In a classical twin study with 198 elderly twins we examined the contributions of genetic versus environmental factors to nucleic acid oxidation and lipid peroxidation. Urinary excretion of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and dinor,dihydro F₂-isoprostane metabolites (F₂-IsoP-M) was measured using liquid chromatography–tandem mass spectrometry. The environmental influence on nucleic acid oxidation and lipid peroxidation was predominant, leaving only little influence from genetic factors, as evidenced by no differences in intraclass correlations between monozygotic (MZ) and dizygotic (DZ) twins, neither for 8-oxodG (r_MZ = 0.55, r_DZ = 0.47; P = 0.43), F₂-IsoP-M (r_MZ = 0.33, r_DZ = 0.22; P = 0.42), nor 8-oxoGuo (r_MZ = 0.45, r_DZ = 0.58; P = 0.21). Accordingly, heritability estimates for the three markers of oxidative damage were low (h² = 0.17–0.22). The three urinary markers of oxidative stress were closely correlated (r = 0.60–0.84). In conclusion, we demonstrated in a large population of elderly Danish twins that “whole-body” oxidative damage to nucleic acids and lipids is predominantly determined by potentially modifiable nongenetic factors.     

Association of urinary 15-F2t-isoprostane level with oxygen desaturation and carotid intima–media thickness in nonobese sleep apnea patients

Obstructive sleep apnea (OSA) is characterized by recurrent apnea during sleep that may unbalance oxidative stress, increasing atherosclerosis. Among oxidative stress markers, 15-F_2t-isoprostane is considered one of the most sensitive and specific metabolites of lipid peroxidation. To explore the relationship between urinary 15-F_2t-isoprostane with sleep apnea severity and carotid modifications in nonobese OSA patients, 31 nonobese sleep apnea patients were studied, along with 10 lean subjects without OSA. Patients were assessed by polysomnography, blood pressure measurement, and ultrasonography to determine the carotid intima–media thickness (IMT). Urinary 15-F_2t-isoprostanes were measured by liquid chromatography–tandem mass spectrometry. Urinary 15-F_2t-isoprostane concentrations were increased in severe OSA patients compared to control subjects (20.2 ± 7.3 vs 12.3 ± 2.8 ng/mmol creatinine; P = 0.020). Mean carotid IMT was correlated with 15-F_2t-isoprostane (r = 0.532; P < 0.001) and with the apnea–hypopnea index (r = 0.345; P = 0.029). 15-F_2t-Isoprostane level was related to the night time spent at SaO₂ < 90% (r = 0.478; P = 0.002), the apnea–hypopnea index (r = 0.465; P = 0.003), and the mean nocturnal SaO₂ (r = ? 0.424; P = 0.007). These results showed a relationship between lipid peroxidation, carotid intima–media thickness, and intermittent hypoxia in nonobese OSA patients, thus reinforcing the hypothesis that oxidative stress could be involved in the early atherosclerotic process.     

Plasma levels of trace elements and exercise induced stress hormones in well-trained athletes

This study analyzed the variation and relationship of several trace elements, metabolic substrates and stress hormones activated by exercise during incremental exercise. Seventeen well-trained endurance athletes performed a cycle ergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, the workload was increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Prior diet, activity patterns, and levels of exercise training were controlled, and tests timed to minimize variations due to the circadian rhythm. Oxygen uptake, blood lactate concentration, plasma ions (Zn, Se, Mn and Co), serum glucose, non-esterified fatty acids (NEFAs) and several hormones were measured at rest, at the end of each stage and 3, 5 and 7 min post-exercise. Urine specific gravity was measured before and after the test, and participants drank water ad libitum.Significant differences were found in plasma Zn and Se levels as a function of exercise intensity. Zn was significantly correlated with epinephrine, norepinephrine and cortisol (r = 0.884, P < 0.01; r = 0.871, P < 0.01; and r = 0.808, P = 0.05); and Se showed significant positive correlations whit epinephrine and cortisol (r = 0.743, P < 0.05; and r = 0.776, P < 0.05). Neither Zn nor Se levels were associated with insulin or glucagon, and neither Mn nor Co levels were associated with any of the hormones or substrate metabolites studied. Further, while Zn levels were found to be associated only with lactate, plasma Se was significantly correlated with lactate and glucose (respectively for Zn: r = 0.891, P < 0.01; and for Se: r = 0.743, P < 0.05; r = 0.831, P < 0.05).In conclusion, our data suggest that there is a positive correlation between the increases in plasma Zn or Se and stress hormones variations induced by exercise along different submaximal intensities in well-hydrated well-trained endurance athletes.     

Prediction of all-cause mortality with copeptin in cardio-cerebrovascular patients: A meta-analysis of prospective studies

BackgroundMeasurement of the biomarker copeptin may help identify disease severity and risk of mortality for a various diseases. This study sought to determine the relationship between copeptin and all-cause mortality of patients with cardio-cerebrovascular disease.MethodsDatabase of Medline and Web of Science were searched for studies with data involving the baseline copeptin levels and subsequent all-cause mortality outcomes. The pooled HRs of all-cause mortality were calculated and presented with 95%CIs. Subgroup analysis and sensitivity analysis were conducted to explore the possible sources of heterogeneity.ResultsData from 14,395 participants were derived from 28 prospective studies. Higher copeptin significantly increased the risk of all-cause mortality (per unit copeptin: HR = 1.020, 95%CI = 1.004–1.036; log unit copeptin: HR = 2.884, 95%CI = 1.844–4.512; categorical copeptin: HR = 3.371, 95%CI = 2.077–5.472). Subgroup analysis indicated that the risk of all-cause death was higher in cerebrovascular patients (per unit copeptin: HR = 2.537, 95%CI = 0.956–6.731; log unit copeptin: HR = 3.419, 95%CI = 2.391–4.888) than cardiovascular patients (per unit copeptin: HR = 1.011, 95%CI = 1.002–1.020; log unit copeptin: HR = 2.009, 95%CI = 1.119–3.608).ConclusionCopeptin is associated with all-cause mortality of patients with cardiovascular and cerebrovascular disease. Our study suggests that copeptin seems to be a promising novel biomarker for prediction of mortality in cardio-cerebrovascular patients, especially for cerebrovascular patients.     

Local control rates in stereotactic body radiotherapy (SBRT) of lung metastases associated with the biologically effective dose

AimTo evaluate dose differences in lung metastases treated with stereotactic body radiotherapy (SBRT), and the correlation with local control, regarding the dose algorithm, target volume and tissue density.BackgroundSeveral studies showed excellent local control rates in SBRT for lung metastases, with different fractionation schemes depending on the tumour location or size. These results depend on the dose distributions received by the lesions in terms of the tissue heterogeneity corrections performed by the dose algorithms.Materials and methodsForty-seven lung metastases treated with SBRT, using intrafraction control and respiratory gating with internal fiducial markers as surrogates (ExacTrac, BrainLAB AG), were calculated using Pencil Beam (PB) and Monte Carlo (MC) (iPlan, BrainLAB AG).Dose differences between both algorithms were obtained for the dose received by 99% (D_99%) and 50% (D_50%) of the planning treatment volume (PTV). The biologically effective dose delivered to 99% (BED_99%) and 50% (BED_50%) of the PTV were estimated from the MC results. Local control was evaluated after 24 months of median follow-up (range: 3–52 months).ResultsThe greatest variations (40.0% in ΔD_99% and 38.4% in ΔD_50%) were found for the lower volume and density cases. The BED_99% and BED_50% were strongly correlated with observed local control rates: 100% and 61.5% for BED_99% > 85 Gy and <85 Gy (p < 0.0001), respectively, and 100% and 58.3% for BED_50% > 100 Gy and <100 Gy (p < 0.0001), respectively.ConclusionsLung metastases treated with SBRT, with delivered BED_99% > 85 Gy and BED_50% > 100 Gy, present better local control rates than those treated with lower BED values (p = 0.001).     

Depot-specific modulation of adipokine levels in rat adipose tissue by diet-induced obesity: The effect of aerobic training and energy restriction

The present study examined the effects of aerobic training and energy restriction on adipokines levels in mesenteric (MEAT) and retroperitoneal (RPAT) white adipose tissue from obese rats. Male Wistar rats were fed with standard laboratory diet (Control group) or high fat diet (HFD). After 15 weeks, HFD rats were randomly assigned to the following groups: rats submitted to HFD, which were sedentary (sedentary HFD, n = 8) or trained (trained HFD, n = 8); or submitted to energy-restriction (ER), which were sedentary (sedentary ER, n = 8) or trained (trained ER, n = 8). Trained rats ran on a treadmill at 55% VO_2max for 60 min/day, 5 days/week, for 10 weeks. ER rats were submitted to a reduction of 20% daily caloric ingestion compared to the Control group. ER and aerobic training decreased body weight, MEAT and RPAT absolute weight, and fat mass. IL-6, IL-10 and TNF-α levels were decreased and adiponectin did not change in RPAT in response to ER protocol. On the other hand, ER and the aerobic training protocol decreased IL-6, TNF-α and adiponectin levels in MEAT. Absolute MEAT weight showed a positive correlation with IL-6 (r = 0.464), TNF-α (r = 0.508); and adiponectin (r = 0.342). These results suggest a tissue-specific heterogeneous response in adipokines level. The combination of the protocols (aerobic training and energy restriction) did not induce an enhanced effect.     

The influence of myosin heavy chain isoform content on mechanical behavior of the vastus lateralis in vivo

This study examined correlations between type I percent myosin heavy chain isoform content (%MHC) and mechanomyographic amplitude (MMG_RMS) during isometric muscle actions. Fifteen (age = 21.63 ± 2.39) participants performed 40% and 70% maximal voluntary contractions (MVC) of the leg extensors that included increasing, steady force, and decreasing segments. Muscle biopsies were collected and MMG was recorded from the vastus lateralis. Linear regressions were fit to the natural-log transformed MMG_RMS–force relationships (increasing and decreasing segments) and MMG_RMS was selected at the targeted force level during the steady force segment. Correlations were calculated among type I%MHC and the b (slopes) terms from the MMG_RMS–force relationships and MMG_RMS at the targeted force. For the 40% MVC, correlations were significant (P < 0.02) between type I%MHC and the b terms from the increasing (r = −0.804) and decreasing (r = −0.568) segments, and MMG_RMS from the steady force segment (r = −0.606). Type I%MHC was only correlated with MMG_RMS during the steady force segment (P = 0.044, r = −0.525) during the 70% MVC. Higher type I%MHC reduced acceleration in MMG_RMS (b terms) during the 40% MVC and the amplitude during the steady force segments. The surface MMG signal recorded during a moderate intensity contraction provided insight on the contractile properties of the VL in vivo.     

Relationship between ventilatory threshold and muscle fiber conduction velocity responses in trained cyclists

The relationship between surface electromyography (SEMG) amplitude and the ventilatory threshold has been extensively studied. However, previous studies of muscle fiber conduction velocity (MFCV) are scarce and present insufficient evidence concerning the relationship between MFCV and metabolic responses during cycling. Based on that fact, the purpose of this study is twofold: (1) to investigate the existence of a MFCV threshold (MFCVT) during cycling and (2) to verify if this possible breakpoint is correlated with the ventilatory threshold (VT) and the SEMG threshold (SEMGT). Eight trained male cyclists (age 36.0 ± 9.7 years) performed an incremental cycling test with initial workload of 150 W gradually incremented by 20 W min^?1 until the exhaustion. Gas analyses were conducted using a breath-by-breath open-circuit spirometry and SEMG were registered from vastus lateralis in each pedaling cycle with a linear array of electrodes. A bi-segmental linear regression computer algorithm was used to estimate VT, MFCVT and SEMGT respectively in the carbon dioxide production (VCO₂), MFCV and electromyography root mean square (EMG RMS) curves. The one way ANOVA for repeated measures did not reveal any significant difference among VT (77.1 ± 7.5% of VO₂max), MFCVT (80.3 ± 10.4% of VO₂max) and SEMGT (81.9 ± 11.7% of VO₂max). The Bland and Altman procedure confirmed a good concordance between SEMGT and VT (Bias = 5.5 of %VO₂max) as well as MFCVT and VT (Bias = 5.2 of %VO₂max). The present findings suggest that muscle fiber conduction velocity threshold is a valid and reliable non-invasive tool to obtain information about ventilatory threshold in trained cyclists.     

The reliability and criterion validity of 2D video assessment of single leg squat and hop landing

The objective was to assess the intra-tester, within and between day reliability of measurement of hip adduction (HADD) and frontal plane projection angles (FPPA) during single leg squat (SLS) and single leg landing (SLL) using 2D video and the validity of these measurements against those found during 3D motion capture. 15 healthy subjects had their SLS and SLL assessed using 3D motion capture and video analysis. Inter-tester reliability for both SLS and SLL when measuring FPPA and HADD show excellent correlations (ICC_2,1 0.97–0.99). Within and between day assessment of SLS and SLL showed good to excellent correlations for both variables (ICC_3,1 0.72–91). 2D FPPA measures were found to have good correlation with knee abduction angle in 3-D (r = 0.79, p = 0.008) during SLS, and also to knee abduction moment (r = 0.65, p = 0.009). 2D HADD showed very good correlation with 3D HADD during SLS (r = 0.81, p = 0.001), and a good correlation during SLL (r = 0.62, p = 0.013). All other associations were weak (r < 0.4). This study suggests that 2D video kinematics have a reasonable association to what is being measured with 3D motion capture.     

Corrélations entre l'évolution morphologique des membres inférieurs et la récupération fonctionnelle de sujets hémiplégiques

ObjectiveThe aim is to quantify the help provided by recent morphological indicators for hemiplegics patients, after a cerebral vascular accident, during functional rehabilitation. The correlations between functional recovery and the morphological evolution of the muscles and the segments of the lower limb are studied using a MRI system.Material and methodTen adult subjects suffering from vascular hemiplegia have been studied at the ELAN rehabilitation center in Wattrelos. Bobath rehabilitation technique was used to treat patients. Muscular and external volumes of the lower limbs segments, obtained through medical imagery, as well as functional tests (Functional Independence Measure (FIM), Bourges's score and indices of motricity of the pathological limb), were assessed when patients were admitted in and as they left from the rehabilitation centre. Spearman's rho coefficient was used in this study.ResultsThis non-parametric test was considered significant when P < 0.05. It demonstrated a relationship between the evolution of thigh's external and muscular volumes and changes in Bourges's score in seated position (r_s = 0.730 and r_s = 0.764, respectively). It also showed a relationship between pathologic knee motricity index and pathologic leg segment volume evolution (r_s = 0.675).Discussion–conclusionStatistical analysis demonstrated that pathologic thigh volume changes is beneficial to balance during seating as no volume evolution seems to influence balance during standing.     

Tensiomyography of selected lower-limb muscles in professional soccer players

Tensiomyography is a non-invasive method of neuromuscular assessment used to measure muscle action characteristics, muscle tone, and muscle fiber type, and provides information on acute and chronic responses of muscle to different training loads. The aims of the present study were: to analyse differences in muscle response and mechanical characteristics of two major muscles of the lower extremity in a large group of Spanish soccer players according to playing position, and to provide group norms against which clinical findings may be compared. Data were collected from 78 professional soccer players (age 26.6 ± 4.4 years; height: 179.2 ± 5.3 cm; body mass: 75.8 ± 5.3 kg). Tensiomyography was recorded from the rectus femoris (RF) and biceps femoris (BF) muscles after 2 days without take part in any strenuous exercise or training. Five tensiomyographic parameters were analyzed: maximal displacement (D_m), contraction time (T_c), sustain time (T_s), delay time (T_d), and half-relaxation time (T_r). A good to excellent intra-session reliability was found for all contractile parameters (ICC ranged from 0.78 to 0.95). No significant differences between players of any position were observed in absolute values of BF. However, significant differences were observed for T_c, T_r and T_s between the different playing positions on RF (P < 0.05, effect size ranged from 1.3 to 1.6). Professional soccer players showed muscles with ability to rapidly generate force during contractions. The neuromuscular profile provided could help in identifying the normative data that are important for the different positions in order to optimize the training and recovery process of each individual player.     

Flexibilidad psicológica,burnout y satisfacción vital en profesionales que trabajan con personas afectadas de demencia

IntroductionThe clinical complexity of dementia, its physical burden, and the potential assaults associated with psychological and behavioral symptoms, could put healthcare workers working with dementia at high risk of burnout. Certain attitudes toward dementia and certain coping styles may be a protective factor against the stress experienced by these workers. On the other hand, it has been shown that a coping style based on psychological flexibility can prevent the development of burnout in the workplace. The present study analyzes the relationship between levels of burnout, psychological flexibility, attitudes towards dementia and life satisfaction in a sample of healthcare workers who work with people affected by dementia.MethodsA sample of 105 healthcare workers from the Ricard Fortuny Social Hospital was recruited (day hospital, hospitalization unit, and nursing home), and psychological flexibility (AAQII), burnout levels (MBI), life satisfaction (SWL), anxiety (STAI-R), and attitudes towards dementia (EAD) were assessed.ResultsPsychological inflexiblility showed a positive relationship with 2 dimensions of burnout (emotional exhaustion [r = .342, P < .01]; depersonalization [r = .328, P < .01]), and with anxiety (r = .723, P < .01), and also showed a negative relation with life satisfaction (r = ?.485, P < .01) and affect attitude (r = ?.209); p < .05). It was also found a negative relation between rejection attitude with emotional exhaustion (r = ?.328, P < .01) and with depersonalization (r = ?.328; P < .01).ConclusionsThose participants with greater psychological flexibility, in addition to feel more satisfaction with life, were found to be less likely to feel emotionally exhausted, to depersonalize patients with dementia, and felt more affection for them. On the other hand, no relationship was found between Burnout levels and the cognitive dimension of Attitudes towards dementia (the worker's knowledge of dementia). The results have significant implications regarding the type of training that is given to healthcare workers who work with people affected by dementia. Psychoeducational interventions promoting the psychological flexibility could help to reduce the risk of burnout in healthcare workers who work with dementia.     

Design,synthesis and biological screening of some novel celecoxib and etoricoxib analogs with promising COX-2 selectivity,anti-inflammatory activity and gastric safety profile

Two new series of 4,6-diaryl-3-cyanopyridine 4a-r and 1,3,5-triaryl-2-pyrazolines 6a-f and were prepared. The new compounds were evaluated for their in vitro COX-2 selectivity and in vivo anti-inflammatory activity. Compounds 4o,r and 6d,f had moderate to high selectivity index (S.I.) compared to celecoxib (selectivity indexes of 4.5, 3.14, 4.79 and 3.21, respectively) and also, showed in vivo anti-inflammatory activity approximately equal to or higher than celecoxib (edema inhibition % = 60.5, 64.5, 59.3 and 59.3, after 3 h, respectively) and the effective anti-inflammatory doses were (ED₅₀ = 10.1, 7.8, 8.46 and 10.7 mg/kg respectively, celecoxib ED₅₀ = 10.8 mg/kg) and ulcerogenic liability were determined for these compounds which showed promising activity by being more potent than celecoxib with nearly negligible ulcerogenic liability compared to celecoxib (reduction in ulcerogenic liability versus celecoxib = 85, 82, 74 and 67%, respectively).     

Proving of a Mathematical Model of Cell Calculation Based on Apparent Diffusion Coefficient

OBJECTIVES: Recently, Atuegwu et al. proposed a mathematical model based on ADC_mean and ADC_min to calculation of cellularity. Our purpose was to compare the calculated cellularity according to the formula with the estimated cell count by histopathology in different tumors. METHODS: For this study, we re-analyzed our previous data regarding associations between ADC parameters and histopathological findings. Overall, 134 patients with different tumors were acquired for the analysis. For all tumors, the number of tumor cells was calculated according to Atuegwu et al. 2013. We performed a correlation analysis between the calculated and estimated cellularity. Thereby, Pearson's correlation coefficient was used and P < .05 was taken to indicate statistical significance in all instances. RESULTS: The estimated and calculated cellularity correlated well together in HNSCC (r = 0.701, P = .016) and lymphomas (r = 0.661, P = .001), and moderately in rectal cancer (r = 0.510, P = .036). There were no statistically significant correlations between the estimated and calculated cellularity in uterine cervical cancer, meningiomas, and in thyroid cancer. CONCLUSION: The proposed formula for cellularity calculation does not apply for all tumors. It may be used for HNSCC, cerebral lymphomas and rectal cancer, but not for uterine cervical cancer, meningioma, and thyroid cancer. Furthermore, its usefulness should be proved for other tumors.     

Use of tolerance values to diagnose water-quality stressors to aquatic biota in New England streams

Identification of stressors related to biological impairment is critical to biological assessments. We applied nationally derived tolerance indicator values for four water-quality variables to fish and benthic macroinvertebrate assemblages at 29 sites along an urban gradient in New England. Tolerance indicator values (TIVs), as biologically based predictors of water-quality variables, were determined for dissolved oxygen, nitrite plus nitrate (nitrate), total phosphorus, and water temperature for each site based on observed biological assemblages (TIV_O), and for expected assemblages (TIV_E). The quotient method, based on a ratio of the TIVs for observed and expected assemblages (tolerance units), was used to diagnose potential water-quality stressors. In addition, the ratio of measured water-quality values to water-quality criteria (water-quality units) was calculated for each water-quality variable to assess measured water-quality stressors. Results from a RIVPACS predictive model for benthic macroinvertebrates and Bray-Curtis dissimilarity for fish were used to classify sites into categories of good or impaired ecological condition. Significant differences were detected between good and impaired sites for all biological tolerance units (fish and benthic macroinvertebrate assemblages averaged) except for nitrate (P = 0.480), and for all water-quality units except for nitrate (P = 0.183). Diagnosis of water-quality stressors at selected sites was, in general, consistent with State-reported causes of impairment. Tolerance units for benthic macroinvertebrate and fish assemblages were significantly correlated for water temperature (P = 0.001, r = 0.63), dissolved oxygen (P = 0.001, r = 0.61), and total phosphorus (P = 0.001, r = 0.61), but not for nitrate (P = 0.059, r = −0.35). Differences between the two assemblages in site-specific diagnosis of water-quality stressors may be the result of differences in nitrate tolerance.     

Age and sex affect protein metabolism at protein intakes that span the range of adequacy: comparison of leucine kinetics and nitrogen balance data

Research suggests that changes in leucine oxidation (leu_ox) with feeding may reflect adult protein requirements. We evaluated this possibility by assessing the effects of age, sex, and different protein intakes on whole-body leucine kinetics and nitrogen balance. Thirty-four young (n= 18, 22–46 years) and old (n= 16, 63–81 years) men and women completed three 18-day trials with protein intakes of 0.50, 0.75 and 1.00 g protein·kg body weight^? 1·d^? 1. Fasting and fed-state leucine kinetics were quantified on day 12 of each trial using a primed, constant infusion of L-[1-13C]leucine. Protein requirement was estimated using classical nitrogen balance measurements and calculations. Leucine kinetics parameters were influenced by age and sex across all protein intakes. With feeding, leu_ox increased more in old vs. young adults. Independent of age, fasting and fed-state leu_ox were lower, and net leucine balance (fasting+fed-state) was higher in women vs. men. Among all subjects and protein intakes, nitrogen balance was correlated with fed-state leu_ox (r= 0.39), fed-state leucine balance (r= 0.60), net leucine balance (r= 0.49) and the change in leu_ox from the fasting to fed state (r= 0.49) (P<.05 for all results). At the highest protein intake, the change in leu_ox with feeding was inversely correlated with protein requirement (r=?0.39). These findings indicate that leucine kinetics, especially leu_ox, reflect nitrogen balance-based estimates of the need for dietary protein and generally support the view that protein requirement is comparable between young and old adults.     

Early life conditions,reproductive and sexuality-related life history outcomes among human males: A systematic review and meta-analysis

In order to investigate the association between early life conditions and reproductive and sexuality-related life history outcomes among men, we conducted a meta-analysis that compiled the results of 198 articles. A total of 331 effect sizes drawn from 573 samples were included. The meta-analysis revealed that low family socioeconomic status was associated with early sexual debut (r = 0.07), early first birth (r = 0.14), and early marriage (r = 0.03). There was no significant association between family socioeconomic status and pubertal timing or number of sexual partners. Parental absence was associated with early sexual debut (r = ? 0.12), greater number of sexual partners (r = ? 0.19), early first birth (r = ? 0.14), and early marriage (r = ? 0.13). There was no significant association between parental absence and pubertal timing. Small body size before puberty was associated with delayed pubertal timing (r = ? 0.10). There was no significant association between adult body size and number of offspring, and between body size at birth and pubertal timing. Small adult body size, greater number of siblings, and older parents were associated with non-heterosexual orientation (rs = 0.12, 0.03, and 0.03 respectively). Factors such as sampling procedure, data collection method, and age cut-off used to measure family structure change influenced the association between some predictors (e.g., family socioeconomic status) and outcomes (e.g., first birth). The findings are discussed in relation to the utility of life history theory for understanding human male reproductive and sexuality-related outcomes.     

Quadriceps EMG frequency content following isometric lumbar extension exercise

A relationship exists between muscles of the lumbar spine and those of the lower extremity where the quadriceps become more inhibited after lumbar paraspinal. The purpose of this experiment was to compare surface electromyography (sEMG) total frequency content after lumbar paraspinal fatiguing exercise. Scope: 50 subjects performed fatiguing lumbar extension exercise indexed by downward shifts in median frequency calculated from lumbar paraspinal sEMG signal. Before and after each exercise set we recorded maximal, isometric knee extension torque and quadriceps central activation ratio (QI) using the superimposed burst technique while recording vastus lateralis sEMG. We calculated total frequency content of the sEMG signal (fEMG_TOTAL) as the area of the quadriceps sEMG frequency spectrum. Quadriceps fEMG_TOTAL decreased from baseline following the first and second exercise sets. There was no significant change in quadriceps sEMG median frequency among baseline and post-exercise measures. The change in fEMG_TOTAL was correlated with the change in QI following the first (r = ?0.41, P = 0.003) and second (r = ?0.32, P = 0.02) exercise sets. Conclusion: Quadriceps fEMG_TOTAL decreased following fatiguing lumbar extension exercise, in the absence of a significant change in quadriceps median frequency.     

Plasma trace elements levels are not altered by submaximal exercise intensities in well-trained endurance euhydrated athletes

The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes.Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻]_b), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U_SG) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT_OXR), carbohydrate oxidation (CHO_OXR), energy expenditure from fat (EE_FAT), from carbohydrates (EE_CHO) and total EE (EE_T) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at P < 0.05.No significant differences were found in U_SG between, before, and after the test (1.014 ± 0.004 vs. 1.014 ± 0.004 g cm⁻³) or in any plasma ion level as a function of intensity. There were weak significant correlations of Zn (r = 0.332, P < 0.001) and Se (r = 0.242, P < 0.01) with [La⁻]_b, but no relationships were established between [La⁻]_b, VO₂, FAT_OXR, CHO_OXR, EE_FAT, EE_CHO, or EE_T and plasma ion levels.Acute exercise at different submaximal intensities in euhydrated well-trained endurance athletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.     

Relationship between zinc levels and plasma leptin in hemodialysis patients

Recent evidences suggested a possible relationship between zinc deficiency and leptin levels in pathogenesis of anorexia in chronic kidney disease. The present study addressed the relationship between zinc and leptin in hemodialysis (HD) patients.MethodsFifty HD patients (54.3 ± 12.7 years old, 62% men) were studied and compared to 21 healthy volunteers (50.7 ± 15.7 years old, 43% men). Biochemical data, serum zinc, plasma leptin, IL-6, TNF-α and C-Reactive Protein levels were determined. Anthropometric parameters, food intake and appetite score were also assessed.ResultsThe leptin levels were higher in HD patients (16.1 μg/mL (0.21–118.25) vs 6.0 μg/mL (0.50–23.10)) in healthy volunteers (p = 0.04), whereas serum zinc levels were lower (54.5 ± 16.3 μg/dL) compared to healthy volunteers (78.4 ± 9.4 μg/dL) (p = 0.0001). The plasma leptin was correlated negatively with plasma zinc (r = ?0.33; p = 0.007), energy (r = ?0.38; p = 0.002) and protein intake (r = ?0.34; p = 0.006) and, positively correlated with BMI (r = 0.54; p = 0.0001), % body fat (r = 0.70; p = 0.0001) and conicity index (r = 0.46; p = 0.001). Plasma zinc was associated with hemoglobin (r = 0.30; p = 0.04) and negatively associated with TNF-α (r = ?0.37; p = 0.002) and C-Reactive Protein (r = ?0.37; p = 0.004). There was no correlation among Zn, leptin and appetite score in these patients.ConclusionThis study showed that low plasma zinc levels are negatively associated with high leptin levels in HD patients.