A comparison of strength and muscle endurance in strength-trained and untrained women

Muscular strength and fatigability of strength-trained (ST) and untrained (UT) women were compared during a 6-min bout of maximal rhythmic exercise involving the elbow flexor muscles given at a rate of 30 contractions.min-1. Fifteen ST and 15 UT subjects, aged 18-34 years and pair-matched for body size, were tested for differences in initial strength, final strength, absolute endurance, relative endurance, and rate of fatigue. Results revealed a significant difference in initial strength, final strength, and absolute endurance in favor of ST subjects. No significant difference was found for relative endurance, and rates of fatigue were similar for both groups. It is concluded that muscular strength and endurance are enhanced in women engaged in a training program designed primarily to increase muscular strength and hypertrophy, but fatigability is not affected.     

绝经后骨质疏松症患者血清LECT2水平的临床意义及其预测价值分析

摘要 目的：探讨绝经后骨质疏松症患者血清白细胞衍生趋化因子2（LECT2）水平的临床意义及其预测价值。方法：选择2020年1月～2022年1月湖南师范大学第一附属医院收治的绝经后骨质疏松症患者125例作为研究组,另选取同期体检的绝经后健康女性志愿者120例作为对照组。比较两组血清LECT2水平,并分析血清LECT2水平与腰椎和股骨颈骨密度（BMD）及骨代谢相关指标的相关性;应用受试者工作特征（ROC）曲线分析血清LECT2对绝经后骨质疏松症患者的预测价值。结果：研究组血清LECT2、骨钙素（OC）、I型原胶原N端前肽（PINP）、 I型胶原交联C末端肽（S-CTX）显著高于对照组,腰椎和股骨颈BMD显著低于对照组（P<0.05）。Pearson相关分析显示,绝经后骨质疏松症患者血清LECT2水平与OC、PINP、S-CTX水平呈正相关（P<0.05）,与腰椎和股骨颈BMD呈负相关（P<0.05）。ROC曲线分析显示,血清LECT2、OC、PINP、S-CTX联合检验对绝经后骨质疏松症患者的预测价值的曲线下面积（AUC）为0.856,大于各单一指标预测。结论：绝经后骨质疏松症女性血清LECT2水平升高,其水平与骨代谢指标OC、PINP、S-CTX水平呈正相关,与腰椎BMD和股骨颈BMD呈负相关,血清LECT2联合OC、PINP、S-CTX对绝经后骨质疏松症患者的预测价值较高。     

Increased hip internal abduction moment and reduced speed are the gait strategies used by women with knee osteoarthritis

The purpose of this study was to identify the gait strategies in women with mild and moderate knee osteoarthritis (OA). Forty women diagnosed with OA of the knee and 40 healthy women participated in the study. Toe-out progression angle, trunk lateral lean, hip internal abduction moment and gait speed were measured using Qualisys ProReflex System and two force plates. Principal component analysis was applied to extract features from the gait waveforms data that characterized the waveforms main modes of temporal variation. Discriminant analysis with a stepwise model was conducted to determine which strategies could best discriminate groups. According to the discriminant model, the PC2 of the internal abduction moment of the hip and the gait speed were the most discriminatory variables between the groups. The OA group showed decreased gait speed, decreased hip internal abduction moment during the loading response phase, and increased hip internal abduction moment during the mid and terminal stance phases. Interventions that may increase hip internal abduction moment, such as the strengthening of the hip abductors muscles, may benefit women with knee OA. Training slower than normal gait speeds must be considered in light of potential adverse implications on overall physical function, daily tasks, and safety.     

Detrimental effects of endogenous oestrogens on primary acute myocardial infarction among postmenopausal women

Objective

Traditionally, oestrogens were considered to be protective for the cardiovascular system for premenopausal women. Therefore, we conducted a retrospective case–control study to examine the association between endogenous oestrogens and acute myocardial infarction (AMI) risk among postmenopausal women.

Methods

A case–control study was performed among 30 primary AMI patients and 60 control subjects. Baseline characteristics data was collected and endogenous sex hormones levels were determined using chemoluminescence and radioimmunoassay methods. Conditional logistic regression models were developed with adjustment for confounders.

Results

Compared with controls, the circulating oestrone, oestradiol, androstenedione and testosterone levels were significantly higher in AMI patients (P < 0.05) while the sex hormone binding globulin (SHBG) level was lower (P < 0.05). Spearman correlation coefficients showed oestradiol was positively correlated with body mass index (BMI) and waist-to-hip ratio (WHR) in cases, but not in controls. In univariable conditional logistic regression models, oestrone, oestradiol, testosterone, WHR, BMI, diabetes and hypertension were all found to be positively associated with AMI (P < 0.05). After adjusting for these factors, oestradiol (odds ratio (OR) = 4.75; 95 % confidence interval (CI) = 1.07–21.10; P = 0.04) and WHR (OR = 6.46; 95 % CI = 1.09–38.39; P = 0.04) continued to demonstrate strong positive associations with AMI.

Conclusions

A higher level of oestradiol was potentially associated with primary AMI risk among postmenopausal women.     

Recovery after Shift Work: Relation to Coronary Risk Factors in Women

Shift work increases the risk for developing cardiovascular disease. There is, however, little knowledge of what aspects of shift scheduling that are detrimental and what characteristics promote good health. The aim of the present study was to evaluate whether coronary risk factors deteriorate after a hard work period and whether recovery, in the form of a week off, was sufficient to improve them. A total of 19 women worked an extremely rapidly rotating and clockwise shift schedule at a paper and pulp factory. They underwent two health examinations, one at the end of the work period and one after the week off. In addition, the women were divided into a tolerant and a vulnerable group, depending on their satisfaction with their work hours. Most risk factors did not change, but total cholesterol and low‐density lipoprotein (LDL)‐cholesterol were lower after the working period than after the week‐off. In addition, vulnerable women had higher levels of total cholesterol and a higher ratio of total cholesterol/high‐density lipoprotein (HDL) than tolerant ones. In conclusion, the finding that a week‐off worsens cholesterol levels was against our hypothesis and suggests further studies on how activities/responsibilities outside the workplace affect shift‐working women. It was also shown that susceptible shift workers had worse lipid profiles.     

STATES OF DELINQUENCY: RACE AND SCIENCE IN THE MAKING OF CALIFORNIA'S JUVENILE JUSTICE SYSTEM

Literature which debates the degree of liberation or oppression associated with wearing the hijab is frequently focused on the Middle East. Two strands of feminist writing have either condemned the veil as oppressive or reframed it as liberating and as a sign of resistance. I argue that the significance of wearing the hijab in Britain is frequently missed. In Britain far from being a sign of conformity and fulfilling the function of making the wearer invisible the converse is true. The hijab is, of itself, neither liberating nor oppressive; the power relations invested in it are situational and contextual. The white Muslim women who participated in this study experience various kinds of responses from non-Muslims. At times they find themselves on the receiving end of what amounts to racial abuse. In this article I suggest that although neither “race” nor racism are fixed, they tend, nevertheless, to shift as reinventions of the same phenomena.     

Book reviews

John B. Boles (ed.), MASTERS AND SLAVES IN THE HOUSE OF THE LORD: RACE AND RELIGION IN THE AMERICAN SOUTH, 1740–1870, Lexington, KY: The University of Kentucky Press, 1988, 257 pp.

David E. Swift, BLACK PROPHETS OF JUSTICE: ACTIVIST CLERGY BEFORE THE CIVIL WAR, Baton Rouge, Louisiana, LA: Louisiana State University Press, 1989, xv + 384 pp., £31.50.

Alexander B. Murphy, THE REGIONAL DYNAMICS OF LANGUAGE DIFFERENTIATION IN BELGIUM: A STUDY IN CULTURAL‐POLITICAL GEOGRAPHY, Chicago, IL: University of Chicago, Geography Research Paper No. 227, 1988, xiii + 249 pp., $12.00.

Pierre L. van den Berghe, STRANGER IN THEIR MIDST, Denver, CO: University Press of Colorado, 1989, xvii + 300 pp., $24.95.     

Homozygous loss of menin is well tolerated in liver,a tissue not affected in MEN1

In recent studies from Sweden and the United States, a high vitamin A intake has been associated with low bone mineral density (BMD) and increased fracture risk. In Sweden and the United States, food items such as milk and breakfast cereals are fortified with vitamin A, whereas in Denmark there is no mandatory fortification with vitamin A. In the present study, we investigated relations between vitamin A intake and BMD and fracture risk in a Danish population consuming mostly unfortified food items. Within a population-based cohort study in 2,016 perimenopausal women, associations between BMD and vitamin A intake were assessed at baseline and after 5-year follow-up. Moreover, associations between baseline vitamin A intake and 5-year changes in BMD were studied. Finally, fracture risk was assessed in relation to vitamin A intake. In our cohort, dietary retinol intake (0.53 mg/day) was lower than the intake reported in recent studies form Sweden (0.78 mg/day) and the United States (1.66 mg/day). Cross-sectional and longitudinal analyses showed no associations between intake of vitamin A and BMD of the femoral neck or lumbar spine. Neither did BMD differ between those 5% who had the highest, and those 5% who had the lowest, vitamin A intake. During the 5-year study period, 163 subjects sustained a fracture (cases). Compared to 978 controls, logistic regression analyses revealed no difference in vitamin A intake. Thus, in a Danish population, average vitamin A intake is lower than in Sweden and the United States and not associated with detrimental effects on bone.     

绝经后女性血清瘦素、骨密度及血骨特异性碱性磷酸酶和Ⅰ型胶原交联氨基末端肽的测定及意义

目的:测定绝经后女性血清瘦素(leptin)与骨密度及及血清骨特异性碱性磷酸酶(BAP)和Ⅰ型胶原交联氨基末端肽(NTx)并探讨其关系。方法:用酶联免疫吸附试验测定287名40-80岁健康绝经后女性血清leptin以及血清骨特异性碱性磷酸酶(BAP)和Ⅰ型胶原交联氨基末端肽(NTx);用双能X线骨密度扫描仪测定总体、腰椎正位、总髋部骨密度以及体脂、瘦体重;分析它们之间的关系。结果:Leptin与髋部总体BMD呈正相关(r=0.162,P<0.05),校正年龄和体脂后,Leptin与髋部总体BMD相关性消失,Leptin与BAP相关无统计学意义;与NTX呈负相关(r=-0.119,P<0.05),校正年龄和体脂后,相关无统计学意义。BAP与总体骨密度、腰椎骨密度、髋部总体骨密度均呈负相关(r=-0.210,r=-0.236,r=-0.223,P<0.05),校正年龄和体质指数后,相关性都依然存在(r=-0.168,r=-0.187,r=-0.169,P<0.05)。NTx与总体骨密度、腰椎骨密度、髋部总体骨密度均呈负相关(r=-0.238,r=-0.232,r=-0.239,P<0.05),校正年龄和体质指数后...     

Bone and cartilage characteristics in postmenopausal women with mild knee radiographic osteoarthritis and those without radiographic osteoarthritis

Objectives:

To evaluate the association between radiographically-assessed knee osteoarthritis and femoral neck bone characteristics in women with mild knee radiographic osteoarthritis and those without radiographic osteoarthritis.

Methods:

Ninety postmenopausal women (mean age [SD], 58 [4] years; height, 163 [6] cm; weight, 71 [11] kg) participated in this cross-sectional study. The severity of radiographic knee osteoarthritis was defined using Kellgren-Lawrence grades 0=normal (n=12), 1=doubtful (n=25) or 2=minimal (n=53). Femoral neck bone mineral content (BMC), section modulus (Z), and cross-sectional area (CSA) were measured with DXA. The biochemical composition of ipsilateral knee cartilage was estimated using quantitative MRI measures, T2 mapping and dGEMRIC. The associations between radiographic knee osteoarthritis grades and bone and cartilage characteristics were analyzed using generalized linear models.

Results:

Age-, height-, and weight-adjusted femoral neck BMC (p for linearity=0.019), Z (p for linearity=0.033), and CSA (p for linearity=0.019) increased significantly with higher knee osteoarthritis grades. There was no linear relationship between osteoarthritis grades and knee cartilage indices.

Conclusions:

Increased DXA assessed hip bone strength is related to knee osteoarthritis severity. These results are hypothesis driven that there is an inverse relationship between osteoarthritis and osteoporosis. However, MRI assessed measures of cartilage do not discriminate mild radiographic osteoarthritis severity.