儿童血清瘦素与能量代谢关系的研究

目的 研究儿童血清瘦素与能量代谢的关系。方法 对60名正常体重儿童（男，女各30名）采用开放式间接测热法其基础代谢，采用放射免疫法测定血清瘦素，并采用称重法进行为期3d的膳食调查。结果 男童血清瘦素水平与体脂百分比（％BF），脂肪组织（FM）呈正相关（P＜0．05），与能量摄入量，基础代谢无相关性（P＞0．05）；女童血清瘦素水平与BMI，％BF，FM，基础代谢呈正相关（P＜0．05），与能量摄入量无相关性（P＞0．05）。结论 瘦素可能通过其与基础代谢的关系来发挥其调节女童能量平衡及体重的作用。     

Leptin levels,leptin receptor gene polymorphisms,and energy metabolism in women

OBJECTIVE: Resting metabolic rate (RMR) is mainly determined by fat-free mass and additionally by age, sex, hormones, and possibly genetic differences. We evaluated whether leptin levels and polymorphisms in the leptin receptor (LEPR) gene were associated with energy expenditure phenotypes. METHODS: RMR, body composition, and leptin levels were measured in 125 overweight and obese women. Three LEPR polymorphisms, Lys109Arg, Gln223Arg, and Lys656Asn, were typed on genomic DNA of another group of 192 women in whom RMR was measured. Fat, protein, and carbohydrate oxidation were calculated for 103 of these subjects. In 38 subjects, glucose-induced thermogenesis was measured over 3 hours. RESULTS: In the first study group, a negative correlation between RMR and leptin levels was found after controlling for fat and fat-free mass. In multiple regression analysis, leptin contributed significantly to RMR, independent of body composition. In the second study group, RMR was not associated with LEPR polymorphisms. Differences in substrate oxidation rates were found among genotypes at the Lys656Asn site. In fasting conditions, Lys656Lys showed a trend to oxidize more carbohydrates and less fat than Asn656 carriers, a trend which became significant after the glucose load when carbohydrate oxidation rate in Lys656Lys was 15% higher than in Asn656 carriers (p = 0.04), and fat oxidation rate was 44% lower (p = 0.02). DISCUSSION: These results suggest that DNA sequence variations in the LEPR gene could affect substrate oxidation. We hypothesize that this might be caused by differences in glucose levels, leading to differences in glucose oxidation rates.     

Leptin and energy expenditure

PURPOSE OF REVIEW: A fundamental advance in our understanding of endocrine control of energy balance and body weight came with the discovery of the adipocyte-derived hormone leptin. The leptin pathway appeared to be the long-sought peripheral signal pathway from the adipose tissue to the brain involved in the regulation of feeding and energy balance. RECENT FINDINGS: Initially, leptin was considered to function as the long-sought antiobesity hormone. According to this hypothesis, rising concentrations of leptin with increasing adiposity would generate a signal to reduce food intake and increase energy expenditure in order to limit further weight gain. However, widespread resistance to the proposed antiobesity action of leptin is observed in humans, which might reflect the fact that the inability to store energy efficiently at times of abundance is evolutionarily disadvantageous. According to this alternative view, falling leptin concentrations observed during fasting act as a peripheral signal of starvation, which serves to conserve energy in the face of limited reserves. However, leptin administration failed to blunt the changes in energy expenditure during severe energy restrictions in several clinical studies. In addition, leptin therapy in several different human low-leptin states failed to affect energy expenditure in recent studies. SUMMARY: Increasing evidence from human studies suggests that leptin predominantly influences the human energy balance through appetite but appears not to be involved in regulating energy expenditure. None of the expected factors such as resting metabolic rate, total diurnal energy expenditure or dietary induced thermogenesis was related to blood leptin concentrations.     

Response of pulmonary energy metabolism to phosgene

Rats were exposed to phosgene at a concentration of 1.0 ppm for 4 hours in a Rochester-type chamber. At intervals thereafter over a 4 day period, lungs were obtained for histological and biochemical assessments. Edema was estimated by histological examination and by measurement of lung wet and dry weights. In parallel studies, pulmonary mitochondrial respiratory activity was measured using Clark oxygen electrodes. The significant reduction in respiratory control index (State 3 respiration/State 4 respiration) found immediately following phosgene exposure coincided with the highest level of % lung water. There was a concomitant decrease of ATP concentration that persisted on the third day after exposure. Na-K-ATPase activity was reduced 1 day after exposure, thus a lowered ATP level preceded a reduction in Na-K-ATPase or sodium pump activity. The reduction in ATP level and Na-K-ATPase activity may play a major role in damage to lung tissue following exposure to phosgene.     

复治涂阳肺结核与结核病耐药

结核病是严重危害人类健康的呼吸道传染病,是全球关注的公共卫生问题和社会问题.     

载脂蛋白CⅠ和维生素E结合蛋白与肺结核脂质代谢的相关性

目的：探讨载脂蛋白CⅠ（ApoC1）和维生素E结合蛋白（AFM）与肺结核患者脂质代谢的相关性。方法采用ELISA法检测ApoC1、AFM在31例肺结核患者（肺结核组）和26名正常人（正常对照组）血清中的含量,两组均空腹抽血检测总胆固醇、甘油三酯、高密度脂蛋白、低密度脂蛋白、载脂蛋白A1、载脂蛋白B、脂蛋白A和视黄醇结合蛋白等指标,并分析肺结核组血清差异蛋白质与临床检测指标的相关性。结果肺结核组ApoC1含量为（34.60±4.60）μg/mL,显著低于对照组的（38.43±5.12）μg/mL （t=2.703,P<0.01）;肺结核组AFM含量为（15.69±6.79）μg/mL,高于对照组的（11.95±6.36）μg/mL（t=2.054,P<0.05）,且AFM 与患者的甘油三酯含量存在负相关性（rs=-0.371,P<0.05）;ApoC1与所有临床指标均无相关性。结论 ApoC1和AFM可能参与了肺结核患者的脂质代谢。     

Leptin modulates nitric oxide production and lipid metabolism in human placenta

Leptin has significant effects on appetite, energy expenditure, lipid mobilisation and reproduction. During pregnancy, leptin is produced in the placenta, a tissue in which leptin receptors are highly expressed, suggesting autocrine/paracrine functions for this hormone. In the present study, a putative role of leptin as a regulator of nitric oxide (NO) production and lipid metabolism was evaluated in term human placenta. We demonstrated that leptin enhanced NO production in human placental explants (P < 0.01). Although leptin did not modify the placental levels of cholesteryl esters and phospholipids, leptin decreased levels of triglycerides (P < 0.01) and cholesterol (P < 0.001) in term human placenta. The effect of leptin on lipid mass seems to be independent of the modulation of de novo lipid synthesis because leptin did not modify the incorporation of (14)C-acetate into any of the lipids evaluated. We investigated the effects of leptin on placental lipid catabolism and found that in both term human placental explants and primary cultures of trophoblastic cells, leptin increased glycerol release, an index of the hydrolysis of esterified lipids, in a dose-dependent manner. In conclusion, we have shown that leptin affects NO production and lipid catabolism in human placenta, providing supportive evidence for a role of leptin in placental functions that would determine the transfer of nutrients to the developing fetus.     

HIV-associated pulmonary tuberculosis

The problems of diagnosis, treatment and management of tuberculosis associated with HIV infection in Africa are placed in perspective by the former director of the Kenya Medical Research Institute. Tuberculosis (TB) has increased as much as 3-fold in many African countries due to heightened susceptibility of HIV patients. HIV infection may both re-activate latent TB, which virtually all Africans harbor, or increase the likelihood of exogenous infection or re-infection by TB. In most of Africa diagnosis by stained sputum smear is standard: in late AIDS, this method may yield false negatives due to non-pulmonary TB, or pulmonary TB with a negative smear. Chest x-rays are also atypical, since cavitation of the upper zones is not as common, but lobar consolidation and lower zone involvement, and various unusual findings are likely. There is no evidence that mycobacterium avium intracellular has occurred in Africa. Treatment in Africa often centers on long-term thiazina (thiacetazone and isoniazid combined). HIV+ patients are more prone to skin rashes or even lethal epidermal neurolysis as a complication of treatment. Treated patients should be monitored for other symptoms such as diarrhea, recurrent fevers, other chest infections, cerebral space occupying lesions, urinary infections. Many can be treated with broad spectrum antibiotics such as chloramphenicol. Nursing HIV-infected young adults is an expensive and burdensome prospect for overworked and underpaid staff, but curing TB in AIDS patients is possible and worthwhile because of the public health advantages.