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41.
Antisperm antibodies modify plasma membrane functional integrity and inhibit osmosensitive calcium influx in human sperm 总被引:7,自引:0,他引:7
BACKGROUND: The hypo-osmotic swelling (HOS) test evaluates the ability of the functional sperm plasma membrane to stretch following cell swelling when exposed to hypo-osmotic solutions. Sperm samples with low HOS scores show low fertilization and pregnancy rates during assisted reproductive techniques, though data are controversial. The aim of this study was to compare the results of the HOS test in a group of normozoospermic men with those in a group of subjects affected by autoimmune infertility due to the presence of antisperm antibodies (ASA) bound to the sperm surface. METHODS: Sperm from normozoospermic and from infertile subjects affected by autoimmune infertility were exposed to hypo-osmolar conditions to verify the effects on intracellular calcium concentrations and acrosome reaction. RESULTS: Sperm samples from infertile men with ASA showed HOS test scores that were significantly lower than those of normozoospermic subjects despite similar sperm viability percentages. Sperm with ASA bound to their plasma membrane showed a reduced rise in intracellular calcium concentrations and acrosome reaction after hypo-osmotic challenge with respect to sperm from normozoospermic subjects without ASA. CONCLUSIONS: Infertile subjects with ASA have a reduced sperm plasma membrane functional integrity that could explain, at least in part, the low fertilization and pregnancy rates observed in these subjects during assisted reproductive procedures. Evaluation for the presence of ASA in all sperm samples showing low HOS test scores in the presence of normal sperm viability percentages is suggested. 相似文献
42.
The volumes of human erythrocytes after rapid and gradual swelling in hypotonic NaCl media were measured using a Coulter Counter ZB at temperatures of +4°C and +20°C together with potassium leakage, the degree of hemolysis and the ‘returning volume’, i. e., the volume in an isotonic solution to which the cells will return from that in a hypotonic solution. The methodological and systematic errors in the volume measurements were corrected by taking into account the shape dependence of the Coulter Counter and the change in cell population during hemolysis, whereafter the measured cell volume values and the comparison between them become more reliable. The curves for cell volume as an inverse function of osmotic pressure appeared to be non-linear. The slopes were small at first but shoed a rapid increase as the cells approached their maximal volume. The critical hemolytic volume was approx.8% higher at +20°C after both rapid and gradual swelling than at +4°C and approx.4% higher after a gradual swelling as compared with a rapid swelling both at +4°C and +20°C.A decrease in temperature resulted in an increase in the critical osmotic pressure both in rapid and gradual hemolysis, but did not greatly affect the amount of prelytic K+ leakage. The critical osmotic pressure was smaller in gradual hemolysis than in rapid hemolysis and the prelytic K+ leakage was doubled at both +4°C and +20°C.The shifts in osmotic fragility as a function of temperature may be due to differences in the visco-elastic properties of the cell membrane, but the shifts in osmotic fragility as a function of swelling rate may be connected with differences in potassium leakage and membrane stretch. 相似文献
43.
S. M. Bychkov S. S. Nikolaeva V. N. Kharlamova 《Bulletin of experimental biology and medicine》1976,82(4):1510-1512
Structural-mechanical strength and swelling of gels consisting of gelatin and potassium hyaluronate (PHY) or potassium protine-chondroitin-4-sulfate (PPCS) were shown to depend on the ratio between the components. With low concentrations of PHY and PPCS the minimum of structural-mechanical strength coincided with the maximum of swelling of the gels. In zones of neutralization of the positive electric charges of gelatin by macropolyanions, high structural-mechanical strength of the gels coincided with the minimum of swelling. In high concentrations of PHY, structural-mechanical strength and swelling of the gel became equal to the values characteristic of a gel consisting of gelatin only, but in high concentration of PPCS there was an additional parallel increase in this strength and in swelling of the gel.(Presented by Academician of the Academy of Medical Sciences of the USSR S. S. Debov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1211–1213, October, 1976. 相似文献
44.
Control strategies in directing the hand to moving targets 总被引:2,自引:0,他引:2
P. van Donkelaar R. G. Lee R. S. Gellman 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1992,91(1):151-161
Summary We have evaluated the use of visual information about the movement of a target in two tasks tracking and interceptions — involving multi-joint reaching movements with the arm. Target velocity was either varied in a pseudorandom order (random condition) or was kept constant (predictable condition) across trials. Response latency decreased as target velocity increased in each condition. A simple model that assumes that latency is the sum of two components — the time taken for target motion to be detected, and a fixed processing time — provides a good fit to the data. Results from a step-ramp experiment, in which the target stepped a small distance immediately preceding the onset of the ramp motion, were consistent with this model. The characteristics of the first 100 ms of the response depended on the amount of information about target motion available to the subject. In the tracking task with randomly varied target velocities, the initial changes in hand velocity were largely independent of target velocity. In contrast, when the velocity was predictable the initial hand velocity depended on target velocity. Analogously, the initial changes in the direction of hand motion in the interception task were independent of target velocity in the random condition, but depended on target velocity in the predictable condition. The time course for development of response dependence was estimated by controlling the amount of visual information about target velocity available to the subject before the onset of limb movement. The results suggest that when target velocity was random, hand movement started before visual motion processing was complete. The response was subsequently adjusted after target velocity was computed. Subjects displayed idiosyncratic strategies during the catch-up phase in the tracking task. The peak hand velocity depended on target velocity and was similar for all subjects. The time at which the peak occurred, in contrast, varied substantially among subjects. In the interception task the hand paths were straighter in the predictable than in the random condition. This appeared to be the result of making adjustments in movement direction in the former condition to correct for initially inappropriate responses. 相似文献
45.
As previously reported, unilateral pyramidotomy in newborn rats results in the development of an aberrant ipsilateral corticospinal tract that originates from the intact side. In the present study, limb preference after unilateral pyramidotomy in adult and neonatal rats was examined in search of differences that might correlate with this aberrant tract. However, no significant differences were observed between the two groups. Postoperatively, adult animals preferred the limb corresponding to the intact corticospinal tract in spite of a pre- and postoperative testing bias toward the opposite limb. Similarly, the animals that sustained neonatal lesion followed by testing at maturity also preferred the limb corresponding to the normal crossed corticospinal tract. 相似文献
46.
The present study investigated effects of inhibiting the synthesis of prostaglandins (PGs) on cyclic AMP concentrations and chondrogenesis in cultured chick limb mesenchyme. Indomethacin produced concentration-dependent inhibition of both PGE2 synthesis and chondrogenesis over a concentration range of 50--200 M. Half maximal inhibition of PGE2 was achieved with 50 M concentrations of the drug which also produced visibly reduced amounts of cartilage matrix in cell cultures as evaluated by Alcian green staining on day 6 of culture. The inhibitory effects of indomethacin on chondrogenesis were largely reversed by addition of 1 mM dibutyryl cAMP, indicating that cells could still respond to cyclic AMP stimulation. Endogenous levels of cyclic AMP, which increased by 6 fold during the six days of culture in control cells, did not increase significantly from dissociated cells at the time of plating (day 0) in indomethacin-treated cultures. The results indicate that inhibition of the prechondrogenic rise in PGE2 concentrations in limb mesenchyme prevents the increase in cyclic AMP levels which occur during this same period resulting in inhibition of chondrogenesis. The data provide further support for the hypothesis that PGE2, through its effects on the adenylate cyclase-cAMP system, plays an important role in the differentiation of cartilage. 相似文献
47.
Francisco Cordobes Ramiro D. Lobato Juan J. Rivas Jaime M. Portillo Maria Sarabia Maria J. Munoz 《Child's nervous system》1987,3(4):235-238
Eighteen children with severe head injuries and diffuse brain swelling were studied. They were separated into two groups based on the computed tomography (CT) findings. Seven patients had small ventricles in the normal location and small or absent cisterns. Eleven had these signs plus small deep-seated intraparenchymal hemorrhagic foci and/or intraventricular hemorrhage. Patients in the first group were in relatively good neurological condition; their intracranial pressure was easily controlled and all had a favourable outcome. On contrast, children in the second group had a more severe clinical presentation, frequently had uncontrollable intracranial hypertension, and more than 50% died. 相似文献
48.
为观察葛根素是否有对抗星形胶质细胞肿胀及脑水肿的作用 ,体外实验用培养的星形胶质细胞进行 ,整体实验用Wistar雄性大鼠tACPD(5 0 0nmol,2 μL)尾状核内微量注射的方法 ,分别测定星形胶质细胞水含量、脑组织水含量和Na+ 、K+ 、Ca2 + 含量 ,部分脑组织进行电镜观察。结果显示葛根素可以阻断tACPD引起的星形胶质细胞水含量增加 ,减轻由tACPD尾状核内注射引起的脑组织水含量和Na+ 含量增加 ,电镜检查证实葛根素可以减轻tACPD引起的星形胶质细胞肿胀及足突肿胀对毛细血管的挤压。提示葛根素可以对抗星形胶质细胞肿胀及脑水肿。 相似文献
49.
50.
目的 探讨膝胸卧位红光照射联合肛提运动对产后痔急性发作的改善效果.方法 将68例经阴道分娩并发产后痔急性发作的产妇按入院时间分为对照组36例、观察组32例.两组产妇产后给予相同的产褥期知识宣教、母婴护理指导等常规护理措施,在此基础上,对照组采用屈膝侧卧位配合红光照射,观察组给予膝胸卧位红光照射联合肛提运动.观察两组产后24 h和产后5d痔疼痛程度、肛周水肿程度、治疗效果、治疗过程舒适度.结果 干预后两组疼痛评分、肛周水肿程度、治疗效果比较,差异有统计学意义(均P<0.01);两组治疗过程舒适程度差异无统计学意义(P>0.05).结论 产后痔急性发作的产妇应用膝胸卧位红光照射配合肛提运动能有效减轻产妇疼痛及肛周水肿程度,治疗效果较好. 相似文献