Impact of seminal and serum zinc on semen quality and hormonal status: A population-based cohort study of Russian young men

BackgroundTrace elements are important factors in human reproductive health. Among them, special attention is paid to zinc, which is an essential trace element and is necessary for the normal functioning of the male reproductive system and the process of spermatogenesis. The aim of the study was to investigate the association between seminal and serum zinc concentrations and semen quality and reproductive hormone levels in population of Russian young men.MethodsThe study population consisted of 626 young Russian men (median age 22.5 years), recruited from the general population, regardless of their fertility status. Each participant provided semen and blood sample, information about his lifestyle and ethnicity. Semen quality (sperm concentration, motility and morphology), reproductive hormone levels (testosterone, estradiol, LH, FSH and inhibin B), and serum and seminal zinc concentrations were evaluated. The semen samples were analyzed according to the WHO laboratory manual (WHO, 2010). Serum hormones were measured by enzyme immunoassay, zinc concentrations were determined using spectrophotometry and direct colorimetry without deproteinization.ResultsZinc was present in the seminal plasma in a significantly higher concentration than in the blood serum (median serum Zn concentration was 23.6 μmol/L vs seminal Zn concentration 1571.8 μmol/L). The seminal zinc concentration was positively related to the total sperm count, sperm concentration, progressive motility and normal morphology (Spearman’s test: 0.221; 0.286; 0.269; 0.183, respectively, p < 0.001), while the serum Zn concentration was negatively related to serum testosterone and estradiol levels (r = −0.249 and r = −0.096, respectively, p < 0.001−0.05). It was found that the seminal Zn content in men with normal semen quality was higher compared to men with lowered semen quality (means: 6.37 and 5.03 μmol/ejaculate, respectively, p < 0.001). Similarly, the semen volume, total sperm count, sperm concentration, progressive motility, normal morphology and the serum testosterone level in men with the seminal Zn deficiency were lower than in men with the normal seminal Zn content.ConclusionBased on the results of our population-based study, seminal Zn levels were closely associated with semen parameters in young men, so Zn deficiency may be an important risk factor for lowered semen quality. Seminal Zn determinations should be considered as a useful tool in addition to other parameters in assessing male fertility.     

医患沟通技能培养在生殖医学教育中的实践及体会

目的：探讨医患沟通技能培养对生殖医学教育的作用及效果。方法：选择2010 级临床本科专业两个班级共30 人作为观察 组,进行医患沟通技能培养;另选取同年级的两个班级共28 人作为对照组,进行传统生殖医学教学模式培养。运用自行编制的教 学效果调查问卷及SEGUE 量表对两组学生的教学效果及医患沟通技能进行评价及比较。结果：与对照组相比,观察组的教学效 果有明显优势,学生对生殖医学更感兴趣,使生殖医学的教学更富有启发性,学生处理问题的能力显著增强,学生对生殖医学的 知识掌握程度及综合应用能力显著提高,差异具有统计学意义（P<0.05）;与对照组相比,观察组学生在信息收集、信息给予、理解 病人及沟通结束等四个维度的医患沟通能力显著增强,差异具有统计学意义（P<0.05）。结论：在生殖医学教育中加强医患沟通技 能的培养是一种行之有效的教学方法,值得推广。     

Environmental Cues,Endocrine Factors,and Reproductive Diapause in Male Insects

Environmental cues, mostly photoperiod and temperature, mediated by effects on the neuroendocrine system, control reproductive diapause in female insects. Arrest of oocyte development characterizes female reproductive diapause, which has two major adaptive functions: It improves chances of survival during unfavorable season(s), and/or it confines oviposition to that period of the year that is optimal for survival of the eggs and progeny. Although reproductive diapause is less well studied in male insects, there may be no sex-dependent differences in regard to the first of these functions. The second one, however, is not valid for the male; instead, selection pressure directs the male's reproductive strategy toward maximum chances of fertilization of the female's eggs with minimum waste of energy. Therefore, in species with female reproductive diapause, the males may or may not exhibit diapause, but if they do, their diapause must be adapted to that existing in conspecific females. Male reproductive diapause is defined as a reversible state of inability of the male to inseminate receptive females. In relation to reproductive diapause, there are several patterns of coadaptations between male reproductive strategy and timing of female receptivity, (a) In some insects, the females are receptive in the early part of their diapause; mating occurs during this period and there is no diapause in the male. The male dies shortly after copulation and the female stores the sperms to fertilize the eggs that develop after termination of the female's diapause, (b) In some species, as in the grasshopper Anacridium aegyptium, females are receptive during diapause; though oocyte development is arrested, copulation occurs and the stored sperms fertilize the eggs when the female's diapause ends. Males were claimed to have no diapause, but recent studies have revealed the presence of a reproductive diapause in a proportion of the males. This and other cases show that female receptivity during reproductive diapause may or may not be accompanied by male reproductive diapause. If there is a reproductive diapause in the male, it is controlled by the same endocrine mechanism, the corpora allata (CA), as in the females, (c) In many species females are refractory during their diapause. In these cases, males exhibit reproductive diapause, which may be light, as in the beetle Oulema melanopus, or well established, as in certain grasshoppers, butterflies, and beetles. In the latter cases, male diapause is controlled by similar environmental cues (photoperiod, temperature) and by the same intrinsic mechanism (neuroendocrine system, especially CA) as female diapause. Nevertheless, male diapause is less intense; the environmental cues leading to its termination are less complex and/or less extreme, so male diapause terminates before that of the females. Presumably, male diapause is under two antagonistic selection pressures: A male should not waste energy by courting dia-pausing refractory females, but he should be ready to copulate as soon as the females become receptive, otherwise he may lose in the competition between males for females. Some further strategies, which do not seem to fit the above patterns, are also outlined.     

Energy Cost of Living and Associated Pollution for Beijing Residents

China's remarkable economic growth in the last 3 decades has brought about big improvements in quality of life while simultaneously contributing to serious environmental problems. The aim of all economic activities is, ultimately, to provide the population with products and services. Analyzing environmental impacts of consumption can be valuable for illuminating underlying drivers for energy use and emissions in society. This study applies an environmentally extended input‐output analysis to estimate household environmental impact (HEI) of urban Beijing households at different levels of development. The analysis covers direct and indirect energy use and emissions of carbon dioxide (CO₂), sulfur dioxide (SO₂), and nitrogen oxide (NO_x). On the basis of observations of how HEI varies across income groups, prospects for near‐future changes in HEI are discussed. Results indicate that in 2007, an urban resident in Beijing used, on average, 52 gigajoules of total primary energy supply. The corresponding annual emissions were 4.2 tonnes CO₂, 27 kilograms SO₂, and 17 kilograms NO_x. Of this, only 18% to 34% was used or emitted by the households directly. While the overall expenditure elasticity of energy use is around 0.9, there is a higher elasticity of energy use associated with transport. The results suggest that significant growth in HEI can be expected in the near future, even with substantial energy efficiency improvements.     

Plasticity in juvenile hormone in male burying beetles during breeding: physiological consequences of the loss of a mate

Burying beetles, Nicrophorus orbicollis, have facultative biparental care. They bury and prepare small vertebrate carcasses that provide food for their young. Here we establish the juvenile hormone (JH) profiles of paired females, paired males and single males and investigate some of the environmental and social factors that may affect these profiles. Before larvae hatch JH profiles of paired males and females were similar. However, after larvae hatch and during brood care, JH titers of females were very high and those of single males were significantly higher than those of paired males. We tested the hypothesis that higher JH was a response to the need for increased parental care by manipulating brood size. Although JH titers of single males caring for small versus large broods were not significantly different, when comparing JH titers and larval growth (a measure of parental effort), a significant positive correlation emerged. In contrast, we found that food quality had no effect on JH levels suggesting that increased feeding by males and females after carcass discovery cannot explain the elevation of JH. The regulation of JH in male burying beetles appears thus to be dependent on the presence of a mate and on critical stimuli from young.     

Competition-induced switch in young of the year perch,Perca fluviatilis: an experimental test of resource limitation

Synopis Reproductively developed male fathead minnows, Pimephales promelas, exhibited courtship behaviour in the presence of female conspecifies under laboratory conditions. Male courtship consisted of several distinctive and visually conspicuous behaviours directed toward females, including approach, display, and two contact behaviours, as well as leading behaviour from the female to a suitable spawning site. An ovulated condition in females was not necessary to generate male courtship behaviour; in fact, the amount of courtship exhibited by males may depend inversely on the readiness of females to spawn.     

Life history constraints explain negative relationship between fish productivity and dissolved organic carbon in lakes

Resource availability constrains the life history strategies available to organisms and may thereby limit population growth rates and productivity. We used this conceptual framework to explore the mechanisms driving recently reported negative relationships between fish productivity and dissolved organic carbon (DOC) concentrations in lakes. We studied populations of bluegill (Lepomis macrochirus) in a set of lakes with DOC concentrations ranging from 3 to 24 mg/L; previous work has demonstrated that primary and secondary productivity of food webs is negatively related to DOC concentration across this gradient. For each population, we quantified individual growth rate, age at maturity, age‐specific fecundity, maximum age, length‐weight and length‐egg size relationships, and other life history characteristics. We observed a strong negative relationship between maximum size and DOC concentration; for instance, fish reached masses of 150 to 260 g in low‐DOC lakes but <120 g in high‐DOC lakes. Relationships between fecundity and length, and between egg size and length, were constant across the DOC gradient. Because fish in high‐DOC lakes reached smaller sizes but had similar fecundity and egg size at a given size, their total lifetime fecundity was as much as two orders of magnitude lower than fish in low‐DOC lakes. High DOC concentrations appeared to constrain the range of bluegill life history strategies available; populations in high‐DOC lakes always had low initial growth rates and high ages at maturity, whereas populations in low‐DOC showed higher variability in these traits. This was also the case for the intrinsic rates of natural increase of these populations, which were always low at the high end of the DOC gradient. The potentially lower capacity for fish populations in high‐DOC lakes to recover from exploitation has clear implications for the sustainable management of recreational fisheries in the face of considerable spatial heterogeneity and ongoing temporal change in lake DOC concentrations.     

菠萝中蛋白酶及其他组份在品种间的差异分析

以湛江地区6个主要菠萝品种巴厘、卡因、台农17号、台农16号、粤脆、香水为对象,研究菠萝的组分在品种间的差异及其与菠萝蛋白酶的产率和酶活力之间的相关性,结果显示,不同的菠萝品种间,各组分的含量以及蛋白酶的得率及酶活有显著差异。菠萝果皮和果肉的不同生长部位的蛋白含量、酶活力及酶得率有显著差异。酶得率与蛋白及纤维素含量呈显著正相关;酶活力与糖酸比、得汁率、纤维素含量及Zn含量呈显著负相关,蛋白含量、纤维素含量、糖酸比、得汁率是衡量菠萝产酶品质的重要指标。