Changes in somatotypes of European males between 17 and 24 years

In order to examine the possible changes in somatotype of young males, 14 boys who had been somatotyped annually from 11 to 18 years by the Health-Carter anthropometric rating method were re-somatotyped at 24 years. The analysis focused on years 17, 18 and 24. Discriminant analysis, somatotype dispersion indices and distances, and the I-index were used to analyze the data. The findings showed a significant shift in somatotype from ectomorphmesomorph towards endo-mesomorphy between 17 and 24 years. This shift was greater than that observed by Zuk ('58), and was in the same direction. It is hypothesized that the somatotypes of males become more endo-mesomorphic from 17 years to the mid-twenties.     

Influence of physical activity on tibial bone material properties in laying hens

Laying hens develop a type of osteoporosis that arises from a loss of structural bone, resulting in high incidence of fractures. In this study, a comparison of bone material properties was made for lines of hens created by divergent selection to have high and low bone strength and housed in either individual cages, with restricted mobility, or in an aviary system, with opportunity for increased mobility. Improvement of bone biomechanics in the high line hens and in aviary housing was mainly due to increased bone mass, thicker cortical bone and more medullary bone. However, bone material properties such as cortical and medullary bone mineral composition and crystallinity as well as collagen maturity did not differ between lines. However, bone material properties of birds from the different type of housing were markedly different. The cortical bone in aviary birds had a lower degree of mineralization and bone mineral was less mature and less organized than in caged birds. These differences can be explained by increased bone turnover rates due to the higher physical activity of aviary birds that stimulates bone formation and bone remodeling. Multivariate statistical analyses shows that both cortical and medullary bone contribute to breaking strengthThe cortical thickness was the single most important contributor while its degree of mineralization and porosity had a smaller contribution. Bone properties had poorer correlations with mechanical properties in cage birds than in aviary birds presumably due to the greater number of structural defects of cortical bone in cage birds.     

Effect of exercise training on total daily physical activity in elderly humans

This study examined the effect of 12 weeks of exercise training on daily physical activity in elderly humans. Training consisted of a weekly group session and an individual session with cardio- and weight-stack machines. A group of 15 subjects served as the exercise group [EXER mean age 59 (SD 4) years], and 7 subjects as the controls [CONT mean age 57 (SD 3) years]. Physical activity and physical fitness were measured before the start of training (T), at week 6 and week 12 (T0, T6, T12 respectively) in EXER, and at T0 and T12 in CONT. Physical activity over 14 days was measured using a tri-axial accelerometer and physical fitness was measured during an incremental exercise test. At T12, mean maximal power output had significantly increased in EXER compared to CONT 8 (SD 12) vs -5 (SD 9) W; P < 0.02] and mean submaximal heart rate (at 100 W) had reduced [-10 (SD 7) vs -2 (SD 6) beats x min(-1); P < 0.05]. No differences or changes in physical activity were observed between EXER and CONT. At T6, physical activity on training days was significantly higher than on non-training days (P < 0.001). When the accelerometer output of the training session was subtracted from the accelerometer output on training days, at T12 non-training physical activity was significantly lower than on non-training days (P < 0.004). Accelerometer output of the individual training session at T12 had significantly increased compared to T6 (P < 0.05), whereas, accelerometer output of the group training session had remained unchanged. In conclusion, in elderly subjects an exercise training programme of moderate intensity resulted in an improved physical fitness but had no effect on total daily physical activity. Training activity was compensated for by a decrease in non-training physical activity.     

Preliminary studies on the effect of moderate physical activity on blood levels of glutathione

Molecular epidemiological approaches are being used to study how physical activity may protect against cancer. Prior epidemiological data suggest that physical activity protects against lung cancer; however, interpretation of these data is complicated by potential confounding by smoking. Glutathione (GSH) detoxifies cigarette smoke carcinogens and the paper tests whether physical activity levels are associated with blood GSH levels. Study subjects were enrolled in a chemoprevention trial testing whether antioxidant micronutrient supplementation reduces genetic damage from cigarette smoking. Physical activity data were collected by questionnaire from 178 subjects at 12 months of follow-up in the trial. Total GSH (tGSH), which is the sum of free and protein-bound GSH and glutathione disulfide levels, was measured using the 5,5′-dithiobis-(2-nitrobenzenoic acid) colormetric assay with red blood cell samples collected at the 12-month time point. In multivariate linear regression analyses that controlled for gender and cigarettes smoked per day, tGSH was positively associated with hours per week of moderate intensity activity (β=0.005, p=0.02). Hours per week of vigorous intensity activity were unassociated with tGSH and the effect of moderate activity remained after control for vigorous activity. The results are consistent with prior research showing differential effects of moderate and vigorous activity and suggest a mechanism through which physical activity may influence lung cancer risk.     

Preliminary studies on the effect of moderate physical activity on blood levels of glutathione

Molecular epidemiological approaches are being used to study how physical activity may protect against cancer. Prior epidemiological data suggest that physical activity protects against lung cancer; however, interpretation of these data is complicated by potential confounding by smoking. Glutathione (GSH) detoxifies cigarette smoke carcinogens and the paper tests whether physical activity levels are associated with blood GSH levels. Study subjects were enrolled in a chemoprevention trial testing whether antioxidant micronutrient supplementation reduces genetic damage from cigarette smoking. Physical activity data were collected by questionnaire from 178 subjects at 12 months of follow-up in the trial. Total GSH (tGSH), which is the sum of free and protein-bound GSH and glutathione disulfide levels, was measured using the 5,5'-dithiobis-(2-nitrobenzenoic acid) colormetric assay with red blood cell samples collected at the 12-month time point. In multivariate linear regression analyses that controlled for gender and cigarettes smoked per day, tGSH was positively associated with hours per week of moderate intensity activity (β=0.005, p=0.02). Hours per week of vigorous intensity activity were unassociated with tGSH and the effect of moderate activity remained after control for vigorous activity. The results are consistent with prior research showing differential effects of moderate and vigorous activity and suggest a mechanism through which physical activity may influence lung cancer risk.     

羟基酪醇抑菌活性及抑菌稳定性研究

本研究探究了羟基酪醇对大肠杆菌、金黄色葡萄球菌、铜绿假单胞杆菌和枯草芽孢杆菌等四种供试菌的抑菌活性及抑菌稳定性。采用试管半倍稀释法确定MIC和MBC,并探讨羟基酪醇对供试菌的生长和细胞膜完整性的影响以及在不同介质下的抑菌稳定性。结果表明,羟基酪醇对大肠杆菌、金黄色葡萄球菌、铜绿假单胞杆菌和枯草芽孢杆菌的MIC分别为0.625、0.625、1.250、2.500 mg/mL,MBC分别为1.250、1.250、2.500、5.000 mg/mL。与对照组相比,四种供试菌核酸和可溶性蛋白泄漏显著,细胞膜的完整性被破坏。在不同NaCl浓度下,羟基酪醇对枯草芽孢杆菌的抑菌活性稳定;在1.0%和2.0%NaCl浓度下,羟基酪醇对大肠杆菌和铜绿假单胞杆菌的抑菌活性稳定;在2.0%NaCl介质下低浓度的羟基酪醇对金黄色葡萄球菌的抑菌活性稳定,在0.5%、1.5%和2.0%NaCl介质下高浓度的羟基酪醇对金黄色葡萄球菌的抑菌活性稳定。在蔗糖介质中,羟基酪醇对四种供试菌的抑菌活性均不稳定。因此,羟基酪醇可以作为一种新型的防腐剂。     

Influence of Igepal reverse micellar and micellar systems on activity and stability of heme peroxidases

The activities of horseradish peroxidase (HRP) and lactoperoxidase (LPO) entrapped in reverse micelles of Igepal CO-520 in cyclohexane were studied. When the molar ratio of water to surfactant, w ₀ was ≥13, the activity of HRP encapsulated in the water pool of the reverse micelle was comparable with that measured in buffer. For LPO, however, lower activity was observed after its incorporation into the same system.

The activity of the investigated peroxidases was also measured in an aqueous solution of Igepal CO-720 or after incubation with this surfactant. The enzymes became inactivated in an aqueous micellar solution of Igepal CO-720, although this process was reversible.

The stability of HRP and LPO at 37 or 50°C was lower in the micellar systems than in buffer with the exception for HRP in reverse micelles at 50°C.     

Improving physical activity in COPD: towards a new paradigm

Chronic obstructive pulmonary disease (COPD) is a debilitating disease affecting patients in daily life, both physically and emotionally. Symptoms such as dyspnea and muscle fatigue, lead to exercise intolerance, which, together with behavioral issues, trigger physical inactivity, a key feature of COPD. Physical inactivity is associated with adverse clinical outcomes, including hospitalization and all-cause mortality. Increasing activity levels is crucial for effective management strategies and could lead to improved long-term outcomes. In this review we summarize objective and subjective instruments for evaluating physical activity and focus on interventions such as pulmonary rehabilitation or bronchodilators aimed at increasing activity levels. To date, only limited evidence exists to support the effectiveness of these interventions. We suggest that a multimodal approach comprising pulmonary rehabilitation, pharmacotherapy, and counselling programs aimed at addressing emotional and behavioural aspects of COPD may be an effective way to increase physical activity and improve health status in the long term.     

Influence of level of habitual activity on physical working capacity and body composition of post-puberal school boys.

The relationships between level of habitual activity, physical working capacity at a heart rate of 170 beats per minute (PWC170), % fat and body size, have been investigated in 85 post-puberal males aged 16 to 18. Percentage of fat was estimated from the sum of four skinfold thickness and body size characterized by: height and weight; arm, chest, calf and thigh circumferences; bicromial and bi-iliac diameters. PWC170 was found to be significantly related to level of habitual activity and to most measures of body size; multiple regression analysis indicates that level of habitual activity and size respectively account for 34% and 37% of the variance in PWC170. When differences in the body weight of the subjects were statistically removed, % fat was related positively to arm circumference, and negatively to height and bi-iliac diameter. There was no relationship between % fat and level of habitual activity. The significance of these results is discussed.     

Weekly variation in physical activity of the Oraon agricultural labourers of Jalpaiguri district,West Bengal

The energy expenditure due to habitual physical activity is known to depend on several factors, but possible effects of most of the determinants are not clearly known. The present study deals with weekly variation in energy expenditure of the Oraon agricultural labourers of Jalpaiguri district, West Bengal, India. The results show that, among males, there are significant differences between days of the week. But females do not show any such trend. The possible explanation of the results are the sociocultural practices of the studied population.     

The effect of textured surfaces on postural stability and lower limb muscle activity

Textured insoles may enhance sensory input on the plantar surfaces of the feet, thereby influencing neuromuscular function. The aim of this study was to investigate whether textured surfaces alter postural stability and lower limb muscle activity during quiet bipedal standing balance with eyes open. Anterior–posterior (AP) and mediolateral (ML) sway variables and the intensity of electromyographic (EMG) activity in eight dominant lower limb muscles were collected synchronously over 30 s in 24 young adults under three randomised conditions: control surface (C), texture 1 (T1) and texture 2 (T2). Repeated measures ANOVA showed that the textured surfaces did not significantly affect AP or ML postural sway in comparison to the control condition (p > 0.05). Neither did the textured surfaces significantly alter EMG activity in the lower limbs (p > 0.05). Under the specific conditions of this study, texture did not affect either postural sway or lower limb muscle activity in static bipedal standing. The results of this study point to three areas of further work including the effect of textured surfaces on postural stability and lower limb muscle activity: (i) in young healthy adults under more vigorous dynamic balance tests, (ii) post-fatigue, and (iii) in older adults presenting age-related deterioration.     

黑果枸杞花青素结构差异对其稳定性及细胞抗氧化活性的影响

本文研究了黑果枸杞花青素化合物结构对其稳定性和细胞抗氧化活性的影响。通过半制备型HPLC分离纯化得到了4种黑果枸杞花青素化合物并鉴定结构,利用比色法评价了化合物的稳定性、细胞毒实验以及H₂O₂诱导的SH-SY5Y细胞损伤模型评价了细胞抗氧化活性,并讨论了化学结构对其影响。结果表明反式结构比顺式结构在中性和弱碱性条件下有更好的稳定性,反式结构、糖基的增加以及母核B环上的甲氧基取代均可以通过缩短母核与糖链的分子距离从而提高稳定性,糖基的增加能显著地降低损伤细胞中的乳酸脱氢酶水平,且反式结构较顺式结构更有活性优势。综上所述,黑果枸杞花青素的结构影响稳定性和细胞抗氧化活性,但糖基的增加和酰基的反式异构对二者有更积极的意义。     

提高微生物脂肪酶产量、活性和稳定性的方法研究

微生物脂肪酶是一类广泛应用于诸多工业领域的生物催化剂。提高微生物脂肪酶的产量、活性和稳定性,增强产品的市场竞争力,一直是微生物脂肪酶研究的重点和热点。本文从产脂肪酶菌株的改造、脂肪酶基因的改良、脂肪酶发酵工程和脂肪酶后期处理等四个方面概述了提高微生物脂肪酶产量、活性和稳定性的方法,以期为微生物脂肪酶的规模化工业生产提供方法性指导。     

Influence of complexing agents on stability and activity.

Metal ion-complexing agents, like KCN, EDTA etc., inactivate alkaline phosphatase of pig kidney. This inactivation is reversible at low concentrations of the complexing agents and irreversible at high concentrations. The reversible inhibition is probably due to removal of Zn2+ ions from the active site, where they are necessary for catalytic action, whereas the irreversible inhibition results from the removal of Zn2+ ions necessary for preservation of the structure. The inactivation is pseudo-first order. It depends on the concentration, size and charge of the complexing agents. Beta-Glycerophosphate and Mg2+ ions protect the enzyme from inactivation by complexing agents. Quantitative examination of the effect of substrate leads to a model that is similar to the "sequential model" proposed by D.E. Koshland, G. Nemethy & D. Filmer (1966) (Biochemistry 5, 365-385) to explain allosteric behavior of enzymes. It describes the sequential addition of two substrate molecules at two active centres of the dimer enzyme. The binding of the substrate molecules is accompanied by changes in the conformation, which lead to stabilization of the enzyme against attack by complexing agents.     

Effect of onion-type multilamellar liposomes on Trametes versicolor laccase activity and stability

Trametes versicolor laccase was encapsulated into onion-type, lipid-based multilamellar vesicles (MLVs). When encapsulated, laccase was isolated from the assay medium but was still active once freed from its capsule. The encapsulation efficiency was larger than 65% at 25 °C and 37 °C and decreased to 55% by introducing 140 mM NaCl into the buffered medium (pH = 4.5). MLVs were shown to drastically improve both laccase stability and activity. At 25 °C, laccase activity was doubled in the presence of MLVs. At 37 °C in the salt-free medium, the half-life time of laccase was increased from 2hr 30-65 h without and with MLVs, respectively. This effect was even more pronounced in the salted medium where laccase activity was unchanged for 6 days in the presence of MLVs. These beneficial effects were attributed to the immobilization of laccase onto MLV surface. Laccase activity as well as stability was notably shown to be directly correlated to MLV stability.     

The energy cost of common tasks in rural Nepal: levels of energy expenditure compatible with sustained physical activity

Three hundred and six measurements of energy expenditure by indirect calorimetry of sitting at rest and self-paced activity were made on 41 men, 48 women and 6 adolescents in a mountain village of Nepal. Except for walking and carrying uphill, measured activities fell within the range of values for light to moderate effort, despite appearing physically demanding. Villagers tended to reduce travel speed when carrying heavy loads (54-102% of body mass on various inclines), averaging a moderate level of energy expenditure which could be sustained throughout the day. Such moderately demanding work was also assumed by pregnant, lactating women and young adolescents. Pregnant women worked more slowly at some tasks, but did not differentiate themselves from their non-pregnant, non-lactating counterparts for travel on the mountain side.     

Effects of age and physical performance capacity on distribution and composition of high-density lipoprotein subfractions in men

The influences of age and maximal aerobic capacity (VO2max) on serum lipoproteins with special regard to the concentration, composition and distribution of high density lipoprotein (HDL) subfractions were investigated in 51 healthy males of different characteristics: younger than 35 years, untrained (n = 14, mean age 28.2 years, SD 6.0; VO2max, 47.9 ml.kg-1.min-1, SD 5.8) and trained (n = 11, mean age 27.9 years, SD 4.3; VO2max, 61.1 ml.kg-1.min-1, SD 5.1), older than 50 years untrained (n = 14, mean age 58.9 years, SD 5.9, VO2max, 29.3 ml.kg-1.min-1, SD 5.3) and trained (n = 12, mean age 59.3 years, SD 7.2, VO2max, 45.7 ml.kg-1.min-1, SD 7.7). The fasting-state serum concentrations of total cholesterol, tri-acylglycerol and lipoprotein-cholesterol were measured. The HDL-subfractions were separated by density (rho) gradient ultracentrifugation. Concentrations of cholesterol, cholesterylester, tri-acylglycerol, phospholipids, apolipoprotein (apo) A-I and A-II were measured in the subfractions HDL2b: rho = 1.063-1.100 g.ml-1; HDL2al: rho = 1.00-1.110 g.ml-1; HDL2a2: rho = 1.110-1.150 g.ml-1; HDL3: rho = 1.150-1.210 g.ml-1. Elderly untrained subjects showed increased serum concentrations of total-, very low- and low density lipoprotein-cholesterol and elevated tri-acylglycerol levels. The HDL-cholesterol concentration was decreased, due to reduced concentrations of HDL2-subfractions. Significant changes in the composition of HDL2-subfractions were found in elderly untrained subjects. The HDL2-subfractions had more protein, a decreased apoA-I:A-II ratio and less phospholipids in comparison to HDL2-subfractions from younger untrained and trained, and elderly trained subjects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Interactive effects of habitual physical activity and calcium intake on bone density in boys and girls.

The purpose of this study was to assess the interactive effects of habitual physical activity (total and vigorous intensity) and calcium intake on bone mineral content (BMC) in prepubertal boys and girls. Seventy-six children, aged 8-11 yr, wore accelerometers for up to 7 days to assess activity. Calcium intake was estimated by a 4-day weighted food diary. BMC and areal density (bone mineral density) were measured at the total body, proximal femur, and femoral neck by using dual-energy X-ray absorptiometry. Moderated regression analyses were used to assess the contributions of physical activity (total and vigorous) and calcium intake to BMC, residualized for bone area and body mass. Interactive effects of vigorous activity (> or =6 metabolic equivalents) and calcium intake were found at the total body in boys (b = 2.90 x 10(-3)) and in girls (b = 6.58 x 10(-3)) and at the proximal femur (b = 9.87 x 10(-5)) and femoral neck (b = 2.29 x 10(-5); where b is the regression coefficient from final equation) in boys only; residualized BMC was high only if both vigorous activity and calcium intake were high. There were no interactive effects of total activity and calcium intake. This study provides evidence for synergistic action of habitual vigorous activity and calcium intake on bone mass in children. Recommendations for optimizing bone mass should reflect this synergism.     

Meteorological conditions are associated with physical activities performed in open-air settings

Meteorological conditions (MC) are believed to modify physical activity. However, studies in this area are limited and none have looked at the associations between MC and physical activity in open-air settings. Therefore, we examined the relationships between MC and physical activities performed on sidewalks/streets and outdoor oval tracks. Observation techniques were used to count individuals walking to school, exercising on oval tracks and walking/jogging/biking on sidewalks/streets. Meteorological conditions were obtained from an Automated Surface Observing System located at a nearby airport for the same time periods physical activities were observed. On weekdays, fewer children were seen walking to school and more bicyclists were observed on sidewalks/streets as wind speed increased (p < 0.05). Ambient and apparent temperatures were positively (p < 0.05) and humidity and barometric pressure negatively (p < 0.005) related to the number of individuals walking on the track. Meteorological conditions were not significantly associated with physical activities observed on weekends. Multiple linear regression analyses showed that apparent temperature (+), barometric pressure (−) and dew point (−) accounted for 58.0% of the variance in the number of walkers on the track. A significant proportion of the variance (>30%) in the number of joggers and the length of time they jogged was accounted for by apparent temperature (+) and dew point (−). We found that meteorological conditions are related to physical activity in open-air settings. The results embellish the context in which environmental–physical activity relationships should be interpreted and provide important information for researchers applying the observation method in open-air settings.     

Heritability and genetic etiology of habitual physical activity: a twin study with objective measures

Twin studies with objective measurements suggest habitual physical activity (HPA) are modestly to highly heritable, depending on age. We aimed to confirm or refute this finding and identify relevant genetic variants using a candidate gene approach. HPA was measured for 14 days with a validated triaxial accelerometer (Tracmor) in two populations: (1) 28 monozygotic and 24 dizygotic same-sex twin pairs (aged 22 ± 5 years, BMI 21.8 ± 3.4 kg/m², 21 male, 31 female pairs); (2) 52 and 65 unrelated men and women (aged 21 ± 2 years, BMI 22.0 ± 2.5 kg/m²). Single nucleotide polymorphisms (SNPs) in PPARD, PPARGC1A, NRF1 and MTOR were considered candidates. Association analyses were performed for both groups separately followed by meta-analysis. Structural equation modeling shows significant familiality for HPA, consistent with a role for additive genetic factors (heritability 57 %, 95 % CI 32–74 %, AE model) or common environmental factors (47 %, 95 % CI 23–65 %, CE model). A moderate heritability was observed for the time spent on low- and high-intensity physical activity (P ≤ 0.05), but could not be confirmed for the time spent on moderate-intensity physical activity. For PPARD, each additional effect allele was inversely associated with HPA (P ≤ 0.01; rs2076168 allele C) or tended to be associated with HPA (P ≤ 0.05; rs2267668 allele G). Linkage disequilibrium existed between those two SNPs (alleles A/G and A/C, respectively) and meta-analysis showed that carriers of the AAGC haplotype were less physically active than carriers of the AAAA and AA AC haplotypes combined (P = 0.017). For PPARGC1A, carriers of AA in rs8192678 spent more time on high-intensity physical activity than GG carriers (P = 0.001). No associations were observed with SNPs in NRF1 and MTOR. In conclusion, HPA may be modestly heritable, which is confirmed by an association with variants in PPARD.