Ultrastructure comparée de la spermiogenèse et du spermatozoïde de trois espèces de Paravortex (Rhabdocoela, "Dalyellioida", Graffillidae), Turbellariés parasites intestinaux de Mollusques

Three species of the genus Paravortex were studied. Spermiogenesis involves progressive lengthening of the spermatid. No centriole nor axoneme were found. Thc mature spermatozoon is threadlike, 30μm long and aflagellate. It contains a nucleus, two longitudinal parallel mitochondria, numerous dense bodies limited by a membrane, a row of cortical microtubules and granules. The spatial arrangement of the microtubules wah deduced from a statistical analysis of their number in transverse section. The microtubules are continuous along the length of the spermatozoon and are arranged along a long cone. The granules, not limited by a membrane, are about 25 nm in diameter. They are arranged in a semicircle and represent a new structure for sperm of Platyhclminthes. A statistical comparison demonstrated that two species may be distinguished by the number of their cortical sperm microtubules. This is the tirst ultrastructural study of an aflagellate spermatozoon in the Rhabdocoela. A rickettsia was found in P. cardii .     

Ligand spectrum of hemoglobin activity of methemoglobin-reductase and hemolytic resistance of erythrocytes during chronic exposure to nitrates]

It is found that nitrite-ions formed as a result of biotransformation during long term feeding of calves with sodium and potassium nitrates induce changes in some biochemical parameters of blood, including HS-glutathione content in erythrocytes, acid hemolytic resistance of erythrocytes, activity of NAD-dependent methemoglobin-reductase, correlation of ligand forms of hemoglobin and its total content. It is supposed that the observed changes are of an adaptational character and, as a whole, provide for the optimization of both quantitative and qualitative composition of population of erythroid cells at the expense of erythropoiesis intensification.     

Life history predicts advancement of avian spring migration in response to climate change

An increasing number of studies demonstrate that plant and animal phenologies such as the timing of bird migration have been advancing over the globe, likely as a result of climate change. Even closely related species differ in their phenological responses, and the sources of this variation are poorly established. We used a large, standardized dataset of first arrival dates (FAD) of migratory birds to test the effects of phylogenetic relationships and various life-history and ecological traits on the degree to which different species adapt to climate change by earlier migration in spring. Using the phylogenetic comparative method, we found that the advancement of FAD was greater in species with more generalized diet, shorter migration distance, more broods per year, and less extensive prebreeding molt. In turn, we found little evidence that FAD trends were influenced by competition for mating (polygamy or extra-pair paternity) and breeding opportunities (cavity nests). Our findings were robust to several potentially confounding effects. These evolutionary correlations, coupled with the low levels of phylogenetic dependence we found, indicate that avian migration phenology adapts to climate change as a species-specific response. Our results suggest that the degree of this response is fundamentally shaped by constraints and selection pressures of the species' life history, and less so by the intensity of sexual selection.     

T2 DNA, modified by 2,2,6,6-tetramethyl-4-bromoacetooxypiperidine-i-oxyl as a template for RNA polymerase from E. coli B]

T2-DNA was modified by 2,2,6,6-tetramethyl-4-bromoacetooxypiperidine-1-oxyl (I) at different NaCl concentrations (10(-1) M NaCl--10(-4) M NaCl). Modified DNA were investigated as templates for the RNA-polymerase from E. coli B. It was shown that T2-DNA modified I in 0,1 M NaCl completely preserves the native secondary structure, has a low degree modification (1 molecule I per 1000-2000 nucleotide pairs), but is a noneffective template for the RNA-polymerase from E. coli B (20%-40% as compared with unmodified T2-DNA). Under these conditions the modification occurs probably at the "weakest" (readily melting) sites of DNA. The role of these "weak" sites on DNA as promotors is discussed. The modification of T2-DNA by reagnet I has a stronger inhibitory effect on the total RNA synthesis than on the RNA-synthesis stable to rifampicin. Possible existence of two kinds of "early" promotors on T2-DNA is assumed.     

长春市儿童医院1998～2001年婴幼儿杯状病毒腹泻流行病学研究

人类杯状病毒(human calicivirus,HuCV)是引起儿童和成人非菌性胃肠炎的主要病原之一.为了掌握HuCV在我国的流行情况,1998年7月至2001年6月,从长春市儿童医院2343例5岁以下腹泻患儿中共收集粪便标本1264份,其中1056份来自2135例住院患儿.对轮状病毒检测为阴性的588份标本,经多价酶免疫试验(EIA)和两组引物反转录-聚合酶链反应(RT-PCR)检测HuCV,202份为阳性,其中住院患儿标本178份,HuCV检出率为16.9%.HuCV腹泻以2岁以下儿童为主(占96%),流行高峰季节为11月至次年3月.选择17株HuCV进行分子鉴定,15株属GⅡ-4群,1株属GⅡ-3群,另1株属GⅠ-2群,表明GⅡ-4群HuCV是我国流行的优势株.根据HuCV住院患儿的监测资料初步估计,HuCV腹泻住院率约为0.5‰～2.4‰.讨论了长春地区HuCV的流行趋势和疾病负担.以上结果为我国HuCV腹泻的预防和控制提供了科学依据.     

超声治疗动脉粥样硬化性心血管疾病研究进展

超声干预治疗动脉粥样硬化性心血管疾病（atherosclerotic cardiovascular disease,ASCVD）是一种非侵入性治疗方法，其应用于临床治疗的前景广阔。超声波在身体组织中产生的机械、空化及生化等一系列作用可以有效清除血管中的斑块或血栓。但是，安全性是超声疗法应用于临床中亟需解决的首要问题。超声波在身体组织中的传播会引起组织损伤。另外，安全处理因超声刺激而产生的斑块或血栓碎片也是超声疗法应用中面临的挑战。除了确保安全性，合理制定治疗方案及治疗参数从而提高超声疗法疗效是超声疗法应用于临床中有待解决的重要问题。本文结合近年来超声干预治疗动脉粥样硬化性心血管疾病方面的各种临床、动物及体外模型实验研究结果，综述了超声干预治疗的机制、不同治疗方法和治疗参数的效果、如何确保安全性，以及提高超声疗法疗效需解决的一系列问题，进而提出可能的解决方案。     

Lymphoid structures in the female endometrium in ontogenesis

Lymphoid formations of human endometrium are presented in stroma of the uterine corpus mucous membrane as lymphoid cells (so called diffuse lymphoid tissue), lymphoid nodules and interepithelial lymphocytes in glandular and covering epithelium++. Peculiarities in organization of these formations are seen as slight saturation of the endometrium with lymphoid tissue, small size of lymphoid nodules++. The lymphoid structures in question reach their maximal development during the adolescent and first mature age. During the generative period among diffusely arranged T-lymphocytes sub-populations of T-suppressors predominate. This is probably connected with participation of suppressive mechanisms of local immunity in ensuring blastocyst implantation.     

Reaction of lymphocytes of the endometrium to the intrauterine administration of antigens

In the mucosal membrane of the uterine horns in Wistar white rats mainly small and middle lymphocytes (predominantly T-cells) and rather small amount of plasmocytes and macrophages are presented. After intrauterine administration of bacteria and viruses (BCG vaccine, influenza inactivated liquid vaccine of A type) the local immune reaction develops according to the cellular type with maximum at the first week, before the total immune response, with its peak occurring on the 14th day of the experiment.