Study of muscular work capacity in operators using manual mechanical instruments]

The article contains a hygienic assessment of the influence of vibration on the muscular and working capacity of the workers using manual mechanical devices. The neuro-muscular state evaluation was performed with a manual dynamograph. 161 workers from different professional groups and a sample group of 26 workers were examined. The indices of the maximum muscular force and resistance to fatiguability proved to be the most informative ones. The most apparent neuro-muscular changes were found in the professional groups of moulders and mould-cutters, which could be related to the greatest dosages of vibration and intensive physical overload.     

Kinetic studies on sex difference in susceptibility to chronic benzene intoxication--with special reference to body fat content.

The sex difference in the susceptibility to haematopoietic disorders induced by benzene was studied kinetically with a special reference to its relation with the body fat content. In rats of both sexes with a large body fat content, benzene was eliminated more slowly and remained in the body for a longer time than in rats with a small body fat content. In accord with this finding, the decrease in white blood cell numbers during a chronic benzene exposure was observed only in the groups of rats which had a large volume of fat tissue. In an experimental human exposure, the elimination of benzene was slower in the females than in the males. The kinetic study revealed that the slower elimination in the females is due primarily to the bulky distribution of body fat tissue in that sex. From these results obtained from the experimental exposure of men and rats to benzene, it was concluded that the human female, with her massive body fat tissue, shows an inherent disposition to be susceptible to a chemical such as benzene which has a high affinity with fat tissue.     

Vibration effects on fatty acid composition of organ and cell membrane lipids

The influence of middle and high frequency vibrations (50 and 150 Hz) on the fatty acid pattern of structural lipids in white rat liver, kidney, heart, aorta and muscular tissue was studied in a 3-month experiment. The study also examined the fatty acid composition of phospholipids in erythrocyte cell membranes of workers occupationally exposed to vibrations and of patients suffering from vibration disease. Statistically significant changes in the per cent distribution of fatty acids were observed, which were more evident in the liver and kidney of experimental animals, and also after high frequency (150 Hz) vibration exposure. Changes in human subjects were greater in workers exposed to hand-arm vibrations and in patients suffering from vibration disease. Routine and more precise methods are needed to assess occupational risk via determination of the lipid metabolism state in workers exposed to vibrations and in patients suffering from vibration disease.     

Interrelations between fat distribution, muscle lipid content, adipocytokines, and insulin resistance: effect of moderate weight loss in older women

BACKGROUND: Interrelations between fat distribution, muscle lipid infiltration, adipocytokines, insulin resistance, and moderate weight loss have not been investigated in obese older subjects. OBJECTIVE: The objective was to evaluate relations between fat distribution, muscle lipid content, adipocytokines, and insulin resistance in older women and the effects of moderate weight loss. DESIGN: In 35 healthy women aged 58-83 y, body mass index, waist circumference, sagittal abdominal diameter (SAD), and body composition measured by dual-energy X-ray absorptiometry were evaluated. A midthigh single computed tomography scan was performed to determine subcutaneous adipose tissue (AT), intermuscular AT (IAT), muscular tissue, and muscle lipid infiltration, evaluated as low-density lean tissue. Metabolic variables, insulin resistance measured by homeostasis model assessment, adiponectin, leptin, and high-sensitivity C-reactive protein were measured in all subjects and after weight loss in a subgroup of 15 obese women. RESULTS: Waist circumference and SAD were positively correlated with leptin and insulin resistance and negatively correlated with adiponectin. Adiponectin was associated negatively with insulin resistance and positively with HDL cholesterol, whereas leptin was positively associated with insulin resistance and triacylglycerols. Midthigh subcutaneous AT was associated with insulin resistance and leptin, whereas IAT was associated with triacylglycerols. Stepwise regression with insulin resistance as the dependent variable and body mass index, SAD, triacylglycerols, HDL cholesterol, adiponectin, leptin, high-sensitivity C-reactive protein, and midthigh subcutaneous AT as independent variables showed that SAD entered the regression first (R(2) = 0.492) followed by adiponectin (R(2) = 0.63). After moderate weight loss, midthigh subcutaneous AT, IAT, low-density lean tissue, leptin, and insulin resistance decreased significantly; no significant changes in adiponectin were observed. CONCLUSIONS: Fat distribution indexes and adiponectin are independently associated with insulin resistance. Even in older women, moderate weight loss improves body fat distribution, muscle lipid infiltration, and insulin resistance. Moderate weight loss results in a significant decrease in leptin but no changes in adiponectin.     

A case-control study on the prognosis of vibration syndrome

A case-control study was undertaken to evaluate some factors affecting the prognosis of vibration-induced white finger (VWF), 286 workers, who had used a chain saw in forests and had showed some symptoms and signs that were suspected to be vibration syndrome during some of the years from 1956 to 1980, were selected by medical examinations from a total of 612 forestry workers, and were divided into four groups according to the prognosis of the VWF based on a twenty-year follow-up. The study shows an association between the prognosis of VWF and vibration components, particularly vibration levels, severity of the syndromes not only in peripheral circulation but also in peripheral neuropathy before exposure to vibration ceased. There are also significant associations between the prognosis of peripheral neuromuscular symptoms and the factors of aging and duration of exposure. The study suggests that smoking habits and history of heart failure and diabetes had no effect on the prognosis of VWF.     

Do obese individuals gain weight more easily than nonobese individuals?

A review of studies done on human subjects who were overfed under controlled conditions for periods ranging from 2 to 12 wk shows that the energy cost of induced weight gain is a function of initial body weight and of lean body mass, body fat, and percent body fat. Therefore, bigger and fatter people need to eat more to gain a given amount of weight than do those who are thin. A likely explanation is that obese individuals tend to put on a large proportion of fat, a high-energy tissue, whereas thin people tend to gain more lean, which is a low-energy tissue.     

Clinical aspects of the hand-arm vibration syndrome. A review

At present it seems likely that the different components of the hand-arm vibration syndrome, eg, vibration-induced white finger (VWF), numbing of the hands and arms, muscular fatigue, and occasionally prevalent bone degeneration, may arise independently, and therefore they should be evaluated separately. Evidence of changes caused in the autonomic nervous functions of the body by local vibration is not conclusive. The vascular history should be confirmed objectively with a cold provocation test under laboratory conditions. In individual diagnostics it is useful to record (with modern plethysmographic techniques) the recovery of digital temperature, digital blood pressure, and flow after local cooling. Vibrotactile perception measurement seems to be suitable for group diagnosis. Much of the diagnostic weight for VWF can be obtained from accurate case histories, although, for early changes, the history may be atypical. The lack of simple objective tests for evaluating the hand-arm vibration syndrome makes it difficult to, eg, confirm the history of its different components objectively and estimate the extent of the disability it causes.     

某医院职工人体成分与脂肪肝检出情况研究

目的了解医院职工健康状况,研究体成分与脂肪肝的相关性,更好地预防慢性疾病的发生。方法 2014年2~5月职工体检期间有322名在职及离退休人员参加了体成分测试,结合同期体检腹部彩超结果,分为脂肪肝组与非脂肪肝组,对两组人员的体成分参数进行分析。结果参检者体质量指数(BMI)、体脂百分比、腹围、腰臀比等均值高于正常范围,不同性别参检者BMI、矿物质含量、骨骼肌肉量、蛋白质、身体水分、体脂百分比等有性别差异,P0.01;年龄、内脏脂肪面积、肥胖程度、健康评分等无性别差异,P0.05;男性脂肪肝检出率高于女性,P0.05;脂肪肝组与非脂肪肝组的BMI、矿物质含量、骨骼肌肉量、蛋白质、体脂肪、体脂百分比、内脏脂肪面积、腹围、臀围、腰臀比、健康评分有高度统计学差异,P0.01,内脏脂肪面积分段与脂肪肝检出率有统计学意义,P0.01。结论本组职工超重肥胖率较高,脂肪肝检出率高于近年事业单位体检报道[1-3],慢性疾病潜在危险性较高,脂肪肝组与非脂肪肝组体成分有高度统计学差异,对BMI、腰臀比超标及内脏脂肪面积80cm2的职工进行个体化饮食及运动方式指导,跟踪效果,利于脂肪肝等慢性疾病的预防。     

Ponderostat: Hoarding Behavior Satisfies the Condition for a Lipostat in the Rat

The mass of food hoarded by rats given access to food only two hours per day is proportional to the rats» body weight deficit. The present work investigated whether this behavior might reflect the amount of body fat rather than body weight. The hoarding behavior of three rats was measured every other day at various body weights. After each hoarding session the animals were anesthetized and their percentage of fat was measuredin vivowith a total body electrical conductivity method (TOBEC). The results showed that the amount of food hoarded in the two-hour sessions was inversely proportional to the fat content of the body. This result shows that, in the rat, the fat stored is correlated with the behavioral response leading to the defence of body weight, and therefore satisfies a condition necessary for a lipostat.     

A Case-Control Study on Fat-to-Muscle Ratio and Risk of Breast Cancer

Our objective was to analyze detailed anthropometric characterization for risk of breast cancer in Uruguayan women. The design was a case-control study. The setting was Pereira Rossell Women's Hospital, Montevideo, Uruguay. Subjects were 343 incident breast cancer cases and 1,042 frequency-matched healthy controls who were interviewed on menstrual and reproductive story; and a series of skin folds, circumferences, and diameters were measured to calculate fat and muscle fractions and the derived fat-to-muscle ratio (FMR). Odds ratio (ORs) coefficients were taken as estimates of relative risk derived from unconditional logistic regression. Muscle fraction was negatively associated with risk [OR for highest quartile = 0.23, 95% confidence interval (CI) = 0.15–0.34], fat fraction was positively associated (OR = 3.90, 95% CI = 2.62–5.80), and FMR was positively associated (OR = 4.45, 95% CI = 2.99–6.62). Stratified analyses by body mass index levels also showed risk increases for the highest tertiles of FMR, always displaying significant linear trends. Since increases of risk were found in overweight and in normal weight women, results suggest that fractions and amount of muscle and fat components might be risk factors for breast cancer on the basis of currently existing metabolic and immune interrelationships between adipose and muscular tissue given by glutamine, exercise-derived myokines, and other cytokines produced by these tissues.     

局部振动危害与接振时间关系的调查评价

为探讨接振时间与局部振动危害之间的关系 ,对太原钢铁公司 32 1名局部振动作业工人的手部自觉症状、末梢神经功能和甲皱微循环进行了检查 ,观察其损害程度。结果显示 ,各项检查指标有随接振时间增长而升高的趋势 ,低剂量组低于高剂量组 (P <0 .0 1或P <0 .0 5 ) ,甲皱微循环异常率与痛觉、手麻之间分别存在明显正相关 (r分别为 0 .80 77、0 .72 96 )。提示局部振动对作业工人的手及上肢的各种危害程度与接振时间有关 ,且对末梢神经功能和末梢循环功能的损害同时存在。     

Physical characteristics of vibration in relation to vibration-induced white finger

Predicted and observed prevalences and latency periods of vibration-induced white finger (VWF) were examined among workers exposed to hand-arm vibration. The different physical characteristics of vibration--spectra and impulsiveness--were measured. The following groups of workers were included in the study: forest workers (n = 199), pedestal grinders (n = 12), stone workers (n = 16), shipyard workers (n = 171), and platers (n = 5). The exposure to vibration was measured according to the ISO 5349 method. The impulsiveness of vibration was defined as the difference between peak levels and RMS levels. A good agreement was observed between the predicted and observed data for prevalence and latency of VWF in the forest workers. For the tools with high impulsiveness used in grinding, stone works, and shipyard assembly hall, the results were nonconfirmative; and there was a poor correlation between vibration and VWF. The ISO 5349 standard does not consider the high peak values of the vibration signal which may comprise high-frequency components and cause short transients in the underlying tissue of the worker's hand. These characteristics in vibration may be hazardous in the genesis of VWF and cannot be predicted when measuring vibration by the present standard method.     

Comparative changes of fat digestibility and fat accumulation by the carbon chain length of dietary glycerol tri-homogenous fatty acids in rats

The present study was undertaken to investigate the influence of the carbon chain length of dietary glycerol tri-homogenous fatty acid on fat digestibility and body fat accumulation in rats. Thirty-six Wistar male rats were divided into six groups and fed the semipurified C8, C10, C12, C14, C16, C18 triglyceride diets, respectively. Body weight was significantly lower (p<0.05) in rats fed the C14, C16 and C18 diets than in rats fed the C8, C10 and C12 diets. Weights of adipose tissues and apparent fat digestibility were markedly low in the C16 and C18 fed rats. In these groups, fat content of whole-body carcass was significantly lower (p<0.05), but moisture, ash and protein contents were significantly greater (p<0.05) than those of the other groups. Fatty acid profile of epididymal adipose tissue revealed that dietary C8:0 was not directly incorporated into adipose tissues, and only a small amount of dietary C10:0 was directly deposited as body triglycerides. Meanwhile, dietary C12:0 was extensively incorporated into adipose tissues when compared to those of C8 and C10 rats. The present study indicated that apparent fat and energy digestibilities of dietary glycerol tripalmitin and glycerol tristearin were remarkably lower than the glycerol tricaprylin, tricaprin, trilaurin and trimyristin, which results in lower fat accumulation in the C16 and C18 fed rats.     

Factors related to dioxin and furan body levels among Michigan workers

We evaluated serum concentrations of five selected dioxin, furan, and polychlorinated biphenyls (PCB) congeners among 412 workers at a Midland, Michigan plant that manufactured trichlorophenol and pentachlorophenol (PCP) and formulated chlorophenol-based products. We examined occupational indicators of exposure to these chlorophenols taking into account intrinsic factors such as age and body fat and potential environmental sources of exposure from consumption of local game and fish and other occupations. All five congeners were significantly associated with age and body fat. 2378-TCDD serum concentrations were associated with trichlorophenol operations, total years employed at the plant, as well as working as a hazardous waste worker. 123678-H(6)CDD serum concentrations were related to occupational PCP exposure, chloracne, recent weight loss, eating local game, and working as a hazardous waste worker. Serum concentrations of PCB126 were related to smoking (inversely), and eating local fish or local game. Other factors such as diet and jobs outside of the chlorophenol plant exposures had only a very minor impact on dioxin and furan concentrations in these workers.     

Neuropathy and the automatic analysis of electromyographic signals from vibration exposed workers.

An automatic analysis of the electromyographic activity of the extensor digitorum communis, first dorsal interosseus and opponens pollicis muscles was performed, and both motor and sensory conduction velocities of the median and ulnar nerves were measured in the study of neuropathic changes that occur in traumatic vasospastic disease. Twenty-eight forest workers and 10 pneumatic-tool operators, all with a long occupational exposure to local vibration of the hands, were studied with these neurophysiological methods and general clinical and roentgenological examinations. Twenty male manual workers with a similar age distribution served as the comparison group. The most sensitive measures which separated the subjects with traumatic vasospastic disease from the nonexposed workers were the conduction velocity of the slower motor fibers of the ulnar nerve, the distal sensory conduction velocity and the motor distal latency of the median nerve. The duration and rise time of the averaged muscular potentials of intrinsic hand muscles correlated especially with those nerve conduction velocities which were the most sensitive in exhibiting neuropathic changes.     

Comparison of fat storage between Fischer 344 and obesity-resistant Lou/C rats fed different diets

OBJECTIVE: We aimed to characterize further the Lou/C (LOU) and Fischer 344 (F344) rat strains for nutritional traits to validate their use as contrasting strains for molecular genetic studies. RESEARCH METHODS AND PROCEDURES: Five batches of LOU and F344 rats were used to measure caloric intake, weight gain, and body composition when fed a chow diet, a self-selection diet (together with the study of preferences for macronutrients), hypercaloric diets, and a chow diet in a cold environment. RESULTS: Despite a higher caloric intake when fed a chow diet, LOU rats showed a lower weight gain, final body weight, and percentage of fat tissue, together with a higher percentage of carcass weight, than F344 rats. When fed a self-selection diet, LOU males ingested less protein and more fat than F344 males, and the reverse was observed for females. In this condition, feed efficiency was reduced in LOU but increased in F344 rats compared with the chow diet. Diet-induced obesity was observed in F344 rats but not in LOU rats fed hypercaloric diets. In a cold environment, both LOU and F344 rats displayed an increased percentage of brown adipose tissue compared with control groups, together with a higher caloric intake. DISCUSSION: The study shows robust nutritional differences between the LOU rat, a lean strain with a low feed efficiency and resistant to diet-induced obesity, and the contrasting F344 rat strain. It also shows the interest in these strains for studying the genetic components of resistance to obesity.     

Organochlorines in Danish women: predictors of adipose tissue concentrations

Organochlorines (OCs) are ubiquitously present in the environment, and food of animal origin is currently reported as the major source of exposure. Carcinogenicity in animals raises concern, and OCs may also be a risk factor for both neurological and immunological effects. Our primary objective was to study predictors of adipose tissue levels of dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) in Danish women. We showed that adipose tissue concentrations of DDE and PCBs were consistently positively associated with age and the consumption of fish with a high fat content, while total lifetime duration of lactation had an inverse relationship. The direction of the association with body mass index (BMI) depended on the OC studied. The consumption of meat, fruit, lean fish, medium-fat-content fish, poultry, and eggs was not associated with OC concentrations in our study. We classified fish according to fat percentage, which seems more relevant than considering only total fish consumption. When PCBs were subdivided according to their chemical structure, similar results were obtained for the mono-, di-, and tri-ortho PCBs, indicating that PCBs can be treated as a homogenous group when studying predictors of concentrations in humans. In conclusion, the present study shows that age, lactation, and BMI are consistent predictors of human adipose tissue concentrations of DDE and PCBs and that dietary factors other than fish with a high fat content are not important predictors of these concentrations.     

Assessment of adipose tissue distribution by computed axial tomography in obese women: association with body density and anthropometric measurements

1. Abdominal obesity is associated with numerous metabolic complications. Deep abdominal adipose tissue is critical in the association between the level of abdominal obesity and cardiovascular risk factors. 2. Adipose tissue localization was assessed by computed axial tomography (CAT), and its association with body density and anthropometric measurements was investigated in a sample of fifty-one obese women (percentage body fat 45.9 (SD 5.6)) aged 35.7 (SD 5.5) years. The CAT scans were performed at three levels: lower chest, abdomen and mid-thigh. 3. The total adipose tissue volume computed from these three scans was highly correlated with body fat mass (r 0.94, P less than 0.001). The proportion of deep abdominal fat as measured by the ratio of deep: total adipose tissue areas at the abdominal level was not significantly correlated with body fat mass, but it was moderately associated with the ratio of waist: hip circumferences (WHR) (r 0.49, P less than 0.001). The absolute amount of deep abdominal fat was, however, significantly correlated with body fat mass (r 0.72, P less than 0.001). 4. The subscapular (r 0.38) and the abdominal (r 0.38) skinfolds were the only two skinfolds that were significantly associated with the proportion of deep abdominal fat (P less than 0.01). These skinfolds were also those which showed the highest correlation with the absolute amount of deep abdominal fat (r 0.65, P less than 0.001, for both skinfolds). 5. A three-site CAT-scan procedure can be used for the estimation of body fat mass in premenopausal obese women. 6. In these obese women, there was no significant association between total adiposity and the proportion of deep adipose tissue at the abdominal level. 7. In premenopausal obese women, the absolute amount of deep abdominal fat can be predicted from anthropometric measurements with more accuracy than the relative amount of deep abdominal fat.     

Monte Carlo study of thermal flux profiles and body correction factors for body protein measurements of obese subjects

In previous calculations for Total Body Nitrogen measurements of children, the anterior/posterior thermal neutron flux profile with depth was found to be fairly flat after an initial rise. However, for obese adults significant variations are found in the flux profile with the central flux value being as low as 20% of the peak value. The significance of these flux variations is examined. Correction factors are calculated for the varying attenuation of the nitrogen and hydrogen photons by a range of obese bodies. The calculations included the effect of the thermal flux profile as well as that of an outer layer of low nitrogen content adipose tissue. The bodies are assumed to have a homogeneous hydrogen content. A study of four obese body models with varying sex and fat content shows that the correction factors do not vary much between males and females. This is surprising since the female models are assumed to have a surface fat layer twice as thick as for the male models. The correction factors are found to be only slightly sensitive to the thermal flux variations with depth.