Effects of age on segregation of the X and Y chromosomes in cultured lymphocytes from Chinese men

Chromosome malsegregation in binucleated lymphocytes is a useful endpoint to evaluate age effect on genetic stability. However, the investigations on chromosome malsegregation in binucleated lymphocytes from Chinese are scarce. In this study, peripheral blood lym- phocytes were collected from 14 old （60-70 years） and 10 young （22-26 years） healthy Chinese men. To detect malsegregation of the sex chromosomes, multi-color fluorescence in situ hybridization （FISH） was performed on binucleated lymphocytes, cytokinesis-blocked by cytochalasin B at the first mitosis after phytohaemagglutinin stimulation. Compared with that in young men, a significant increase in frequencies of loss of chromosome X （9.2± 3.2‰ vs. 1.1 ± 0.9‰, P 〈 0.001） and Y （2.5 ± 1.9‰ vs. 0.2± 0.3‰, P 〈 0.001） was found in old men. Similarly, nondisjunction of chromosome X （16.5± 3.4‰ vs. 3.5 ± 1.1‰, P 〈 0.001） and Y （7.2 ± 2.6‰ vs. 2.4 ± 1.3‰, P 〈 0.001） occurred more frequently in old men than in young men. Regardless of donor＇s age, nondisjunction is more prevalent than loss for both chromosome X and Y. The frequencies of observed simultaneous malsegregation were relatively higher than the expected, suggest- ing an association between malsegregation. These results indicated that in Chinese men, malsegregation of the sex chromosomes increases with age in an associated fashion, and nondisjunction accounts for the majority of spontaneous chromosome malsegregation.

Total Energy Expenditure of 16 Chinese Young Men Measured by the Doubly Labeled Water Method

Objective Doubly labeled water （DLW） method is the gold standard for measuring total energy expenditure （TEE）. We used this method to measure TEE in Chinese young men. Methods Sixteen healthy young men age 23±1 recruited. TEE was measured by the DLW method, by indirect calorimetry. We also conducted 24-h estimate energy requirements of the subjects. years with body mass index 22.0±1.4 kg/m2 were and basal energy expenditure （BEE） was determined activity, energy balance and factorial approach to Results TEE of subjects by DLW method was 9.45±0.57 M J/day （2258±180 kcal/day）. The 24-h activity was 10.80±0.33 M J/day （2582±136 kcal/day）. The energy requirement, derived from energy balance observations, was 9.93±1.32 M J/day （2373±315 kcal/day）. The BEE of 6.65±0.28 M J/day （1589±67 kcal/day）, calculated by the adjusted Schofield equation, was significantly higher （P〈O.O01） than that measured by indirect calorimetry, 5.99-±0.66 M J/day （1433-±158 kcal/day）. The TEE derived from the factorial approach was 10.31-±0.43 M J/day （2463±104 kcal/day）. Conclusion The TEE of Chinese young men measured by the DLW method was about 10% lower than the current recommended nutrient intake （RNI）, suggesting that the RNI for Chinese men maybe overestimated. Further studies are warranted to determine the value of the estimated energy requirement.

广东省1213例正常生育力男性精液参数参考值

Semen samples were collected from 1213 fertile men whose partners had a time-to-pregnancy （TTP） _〈12 months in Guangdong Province in Southern China, and semen parameters including semen volume, sperm concentration, total counts, motility, and morphology were evaluated according to the World Health Organization （WHO） 2010 guideline. All semen parameters analyzed were normal in ~62.2% of the total samples, whereas 37.8% showed at least one of the semen parameters below normal threshold values. The fifth centiles （with 95% confidence intervals） were 1.3 （1.2-1.5） ml for semen volume, 20 x 106 （18x106- 20x106） m1-1 for sperm concentration, 40 x 106 （38x106-44x106） per ejaculate for total sperm counts, 48% （47%-53%） for vitality, 39% （36%-43%） for total motility, 25% （23%-27%） for sperm progressive motility, 5.0% （4%,5%） for normal morphology. The pH values ranged from 7.2 to 8.0 with the mean ~ standard deviation at 7.32 ~ 0.17. No effects of age and body mass index were found on semen parameters. Occupation, smoking and alcohol abuse, varicocele appeared to decrease semen quality. Sperm concentration, but not sperm morphology, is positively correlated with TTP, whereas vitality is negatively correlated with TTP. Our study provides the latest reference values for the semen parameters of Chinese fertile men in Guangdong Province, which are close to those described in the new WHO guidelines （5th Edition）.