荧光原位杂交同时检测精子X和Y染色体的方法

用实验手段分离X和Y染色体精子或富集特定性别染色体精子．对于预防性连锁遗传病具有潜在应用价值。建立精子X和Y染色体鉴定方法对于评估分离或富集特定性别染色体效果至关重要。本文介绍采用CY3TM和FlourXTM探针作荧光原位杂交（FISH），同时检测精子Y和X染色体。10份正常精液标本分析结果显示：X染色体精子为50．23％，Y染色体精子为49．77％；有效杂交率达91．99％。FISH方法比传统的精子染色体核型分析和奎纳克林染色检查Y荧光小体更具有简易、特异和快速的优点。     

Skinfold thickness versus isotope dilution for body fat assessment during simulated microgravity: results from three bed-rest campaigns in men and women with and without countermeasures

Because body composition is altered during head-down bed rest (HDBR), body mass can not be used as an index of energy balance. Consequently diet allowances should not be based on body mass evolution but on fat mass changes. Though criticized, skinfold thickness (ST) is the costless, easiest and fastest method to use for such an objective. The aim of this study was to compare the percentage of body fat (%BF) estimated by ST with the isotope dilution of H₂¹⁸O. We compiled data from three HDBR campaigns, one on women (n=8) in November 1998 and two on the same men (n=8) in December 1997 (without countermeasure) and January 1998 (with thigh-cuffs countermeasure), according to a crossover design. Body composition was assessed before and after 6 days of HDBR. %BF was derived from the biceps, triceps, sub-scapular and sup-iliac ST according to Durnin and Wormersly (1974). Fat-free mass was measured on the same day by H₂¹⁸O dilution and fat mass was calculated by the difference with body mass and expressed as a percentage. Based on precision tests, the minimum measurable change by ST was 1.1%BF for single measurement point. Both intercepts (F _4,30=0.89, P=0.45) and slopes (F _4,30=0.74; P=0.57) of the ST versus dilution relationships were not affected by the periods (December vs January), experimental conditions (control vs HDBR vs HDBR + thigh cuffs) or sex allowing the derivation of a common relationship %BF_st=0.94 × %BF_dil (F _1,47=97.9, P<0.0001; non-significant intercept excluded) with a bias between methods of −1.7±2.0 %BF (95% CI: −5.8, 2.4 %BF). ST can be used to measure %BF during HDBR provided great care is placed on training and changes are higher than 1.1 %BF. If the method can be applied for in-flight energy balance monitoring given the high observed energy deficit, a tight monitoring of the individual nutritional status as needed during simulation appears, however, dubious based on this solely method.     

Hyperthermia and maximal oxygen uptake in men and women

To compare the effect of hyperthermia on maximal oxygen uptake (O_2max) in men and women, O_2max was measured in 11 male and 11 female runners under seven conditions involving various ambient temperatures (T_a at 50% RH) and preheating designed to manipulate the esophageal (T_es) and mean skin temperatures at O_2max. The conditions were: 25°C, no preheating (control); 25, 35, 40, and 45°C, with exercise-induced preheating by a 20-min walk at ~33% of control O_2max; 45°C, no preheating; and 45°C, with passive preheating during which T_es and were increased to the same degree as at the end of the 20-min walk at 45°C. Compared to O_2max (l·min^–1) in the control condition (4.52±0.46 in men, 3.01±0.45 in women), O_2max in men and women was reduced with exercise-induced or passive preheating and increased T_a, ~4% at 35°C, ~9% at 40°C and ~18% at 45°C. Percentage reductions (7–36%) in physical performance (treadmill test time to exhaustion) were strongly related to reductions in O_2max (r=0.82–0.84). The effects of hyperthermia on O_2max and physical performance in men and women were almost identical. We conclude that men and women do not differ in their thermal responses to maximal exercise, or in the relationship of hyperthermia to reductions in O_2max and physical performance at high temperature. Data are reported as mean (SD) unless otherwise stated.     

Effects of sex and estrous cycle on modulation of the acoustic startle response in mice

Potential sex differences in amplitude, habituation, prepulse inhibition (PPI) and prepulse facilitation (PPF) of the acoustic startle response (ASR) were investigated using male and female mice from the two different inbred mouse strains C57BL/6J (C57) and C3H. Furthermore, the effects of the estrous cycle were tested. The estrous cycle appeared to have no effect on ASR amplitude, habituation, PPF and PPI, the latter being in contrast to results in rats and humans. While sex had no effect on PPI or PPF, males exhibited higher startle amplitudes than females, irrespective of strain, which we discuss to be due to increased male anxiety. In addition, long-term habituation was stronger in C57 males and short-term habituation was weaker in C3H males with respect to females. These results provide evidence for influence of the reproductive hormones on startle reactivity and startle habituation; we therefore conclude that future studies involving genetic influences on behavior using inbred strains are only complete if both sexes are included.     

儿童阻塞性睡眠呼吸暂停低通气综合征的性别对比研究

目的探讨儿童阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的多导睡眠图(PSG)特点及性别.方法对比分析了277例不同性别儿童的OSAHS的性别年龄比较研究、身高体重及多导睡眠图.结果OSAHS患者,其年龄比例;睡眠时间男(6.80±1.33)h,女(7.08±1.12)h;非快速眼动睡眠潜伏期男(19.87±19.15)min,女(16.62±13.73)min;快速眼动睡眠潜伏期男(1.73±1.10)h,女(1.50±0.78)h;睡眠觉醒次数男(25.68±14.54)次/h,女(23.18±13.44)次/h;最长呼吸暂停时间男(74±77)秒,女(67±43)秒;呼吸暂停及低通气次数男(80.1±112.7)次/h,女(77.9±101.6)次/h;最低血氧男(72.63±16.66)%,女(73.62±11.98)%;平均血氧男(94.42±2.75)%,女(94.02±2.39)%;以及OS-AHS程度等均差异无显著性(p>0.05).结论OSAHS儿童患者性别、各年龄段、体重指数以及PSG检查结果具有一致性,临床上不需区别对待.     

Gender difference in the relationship of performance in the handgrip and standing long jump tests to lean limb volume in young adults

Summary Groups of young, adult males and females performed the handgrip and standing long jump tests. Their total forearm and leg volumes were calculated from a series of circumference and length measurements, and the lean volumes (bone + muscle) calculated by taking the skinfold thickness into consideration. In the handgrip, the mean female performance was 298 N compared with 496 N for the males. In the standing long jump, mean performance expressed as distance x body mass was 87.3 kg · m for females compared with 137.7 kg · m for males. These superior performances of males could simply reflect their greater muscle mass, as the mean lean volumes of female and male limbs respectively were 0.54 l and 0.89 l for forearms, and 11.82 l and 14.82 l for the two legs. However, when the performances of males and females were grouped by lean limb volume, it was found that while in both tests there were linear relationships, males and females did not share a common line. In both tests the male relationship was at a higher level than the female; therefore, for a given lean volume, the male performance was significantly superior to that of the female. The gender difference found in this study has not been seen in other studies in which the performance of skeletal muscle has been related to the cross-sectional area of the active muscles and the possible reasons for the differences are considered.     

关于两个哲学问题的解决

绝对真理与相对真理、矛盾同一性和斗争性相对与绝对的问题,在马克思主义认识论的教学和研究中,一直没有解决。要解决这两个问题,首先应从列宁解决这两个问题的思路着手。马克思主义经典作家包括列宁在内,都没有在客观真理的意义上承认绝对真理,任何客观真理都只能是相对真理,而不能既是相对真理又是绝对真理。“同一性是相对的,斗争性是绝对的”命题,是列宁在比较辩证法和形而上学两种发展现以后提出的,是为了划清两种发展观的界限,而不能把同一性和斗争性与有条件和无条件或静止与运动简单对照起来理解。