The effect of cathartic agents on transmucosal electrical potential difference in the human rectum

Summary Active ion transport in the colon is generating a transmucosal electrical potential difference (PD) of about 40 mV. Cathartic agents inhibit electrolyte and water net-absorption or cause net-secretion which should be reflected in a change of PD.In 83 normal subjects the effect of an isotonic eletrolyte solution (control) and different cathartic agents on rectal PD was tested: Laxatives (bisacodyl, rhein), bile acids (cholic and deoxycholic acid), fatty acids (oleic and ricinoleic acid) and cardiac glycosides (meproscillarin, digitoxin, digoxin). Bisacodyl, deoxycholic acid in high concentration, meproscillarin and digitoxin significantly decreased PD, while the other substances did not.Cathartics act on different transport mechanisms which together with different absorption characteristics of the proximal and distal colon may explain the difference in effecting the PD. Rectal PD measurement provides an easy and convenient tool to document effects of cathartic agents on electrolyte transport, otherwise difficult to obtain, and is applicable for clinical use.To Prof. Dr. H.P. Wolff on the occasion of his 65th birthday     

Sexual dimorphism in digit‐length ratios of laboratory mice

The lengths of the index finger (2D) and ring finger (4D) are sexually dimorphic in humans, and men have a smaller 2D:4D ratio compared to women. Prenatal androgens appear to be important in the development of the 2D:4D sex difference, since it has been reported in children as young as 2 years old, and since humans exposed to supernormal prenatal androgen levels display a smaller 2D:4D ratio. We tested whether another mammalian species in which the process of peripheral sexual differentiation is androgen‐dependent might also show a sex difference in digit ratios. The 2D:4D ratio of adult outbred mice was calculated for both the left and right rear paws. A sex difference was observed in the right rear paw: female mice had a larger 2D:4D ratio than did males. We also found this difference in prepubescent weanling mice. This sex difference is in the same direction as that observed in humans, and suggests that sexual dimorphism in digit length ratios is a feature common to many, if not all, mammals. The mouse may therefore be a useful animal model for studying the factors that influence finger length patterns, which have recently been correlated with several specific behaviors and disease predispositions in humans. Anat Rec 267:231–234, 2002. © 2002 Wiley‐Liss, Inc.     

大鼠大脑白质及白质内有髓神经纤维的性别与年龄差异

目的:研究正常年轻和中老年组雌雄性大鼠大脑白质及白质内有髓神经纤维之间的性别差异,并探讨大脑发育过程中性别差异随年龄增加的改变。方法:运用透射电子显微镜和体视学方法对6~8月龄的年轻Long-Evans大鼠及18月龄同种中老年大鼠大脑白质及其有髓神经纤维进行定量研究。结果:年轻组雄性大鼠大脑白质、有髓神经纤维及其髓鞘的总体积均显著大于雌性,而中老年组雌性大鼠大脑白质、有髓神经纤维体积密度、有髓神经纤维及其髓鞘的总体积均显著大于雄性。结论:年轻组及中老年组大鼠大脑白质、白质内有髓神经纤维及其髓鞘总体积均存在性别差异,随着年龄的增长,雄性大鼠大脑白质及白质内有髓神经纤维体积的减少较雌性更为明显。     

Children's perceptions of peers with somatic symptoms: the impact of gender, stress, and illness

OBJECTIVE: To investigate how illness characteristics influence children's responses to ill peers. METHODS: A sample of 363 4th and 5th graders responded to a vignette describing a peer with abdominal pain. In a 2 x 2 x 2 x 2 design, conditions varied by (a) evidence for organic disease, (b) presence of stress, (c) sex of vignette character, and (d) sex of respondent. Children rated symptom severity, liking for the peer, and whether the peer should be excused from normal responsibilities. RESULTS: Same sex preferences significantly influenced children's liking for a peer. Children viewed symptoms with an organic etiology as more severe than those without one. Under certain conditions, symptom severity judgments mediated the relation between the presence of organic disease and (a) liking and (b) granting relief from responsibility. The presence of stress had little effect on ratings of symptom severity, liking, or relief from responsibility. CONCLUSIONS: Gender and evidence of organic disease influence children's perceptions of and responses to symptomatic peers.     

Temporal aspects of the dependency of a dimorphic rate of extinction on testosterone.

Previous work has shown that rate of extinction of a conditioned taste aversion is affected by concurrent levels of testosterone in adult rats. In the present study, castrated male and female adult rates were given either oil or testosterone during acquisition of the conditioned taste aversion and then either oil or testosterone during extinction. The males and females that received testosterone during the extinction of the aversion showed the slower, masculine rate of extinction regardless of the type of injections they received during acquisition. Conversely, the animals that received oil during extinction showed the faster, feminine rate of extinction regardless of the type of injection during acquisition. In light of these findings, a number of alternative behavioral changes that could account for the effect of testosterone on the rate of extinction were evaluated.     

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.     

噪声作业工人血糖水平与噪声性听力损失的关系

目的 探究血糖与性别之间的交互作用对噪声性听力损失(noise-included hearing loss, NIHL)的影响。 方法 采用病例对照研究,询问调查噪声作业工人一般资料、职业史、既往史等资料以及职业健康监护资料,进行单因素分析,然后采用logistic回归模型分析NIHL的影响因素,再进行乘法交互作用分析。 结果 调查的1 628例噪声作业工人NIHL 616人(37.84%),NIHL的危险因素有血糖偏高(OR=1.960,95%CI:1.345~2.855)、男性(OR=4.346,95%CI:2.866~6.590)、高环境噪声强度(OR=1.036,95%CI:1.016~1.056)、单核细胞计数偏高(OR=8.522,95%CI:3.054~23.776)、血小板偏低(OR=0.997,95%CI:0.994~0.999)。血糖偏高人员的NIHL风险是血糖正常的1.960倍(P＜0.01),男性NIHL的风险是女性的4.346倍(P＜0.01),环境噪声强度每增加一个单位,NIHL风险提高1.036倍。血糖偏高与男性对NIHL的加法交互作用有统计学意义,两者同时存在时OR值为8.962,交互作用指数值为2.123。 结论 有必要考虑将空腹血糖检查纳入噪声作业人员常规检查项目,加强男性噪声作业工人血糖水平的监测,筛查出血糖偏高人群并给予一定的控制、干预,必要时调离工作岗位。     

我国本科医学院校布局及其区域差异性研究

目的:了解当前我国本科医学院校的布局,并对其区域差异性进行深入分析。方法:对院校数量、院校水平利用频数、构成比进行描述性统计;研究院校地区、省份的分布,对区域GDP总量、区域人口与院校规模做相关性分析;用洛伦兹曲线、基尼系数、泰尔指数深入分析院校分布差异性。结果:我国开设医学类专业的本科院校有420所,且分布不均匀;院校水平不一,硕、博点分布不均衡。各省级行政区域的院校硕、博研究生规模主要与该区域GDP总量高度相关,在校生总规模及本科生规模与该区域人口总数相关性更高。院校分布的差异主要源于地区内部,地区间的差异也不容忽视。结论:我国本科医学院校数量相对不足;院校水平不一,硕、博点分布不均;院校分布存在区域差异,需促进区域均衡发展。     

一种基于色差的彩色图像的边缘检测方法

传统的边缘检测方法大都是基于灰度图像的,这就不能充分利用彩色图像的全部信息。文章提出了一种基于色差的彩色图像的边缘检测方法,它能快速准确地检测到图像的边缘,具有低的错判率和较高的效率,优于传统基于灰度的边缘检测方法。     

Stabilization of positive coupled differential‐difference equations with unbounded time‐varying delays

This paper researches the static output‐feedback stabilization of single‐input single‐output (SISO) positive coupled differential‐difference equations (CDDEs) with unbounded time‐varying delays. First, a necessary and sufficient condition is provided for the positivity and asymptotical stability of CDDEs with unbounded time‐varying delays. For this type of system, based on the constructed estimates of its solution, a necessary and sufficient condition on asymptotical stability is provided. Then, based on this criterion, for CDDEs with unbounded time‐varying delays, a kind of static output‐feedback controller is designed to ensure the positivity and asymptotical stability of the corresponding closed‐loop systems. It is also worth pointing out that the controller is designed by the linear programming method without parameterization technique. This design approach can also be applied to the static state feedback stabilization problem of CDDEs with unbounded time‐varying delays. Finally, two illustrative examples are given to show the effectiveness of our results.