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排序方式: 共有271条查询结果,搜索用时 31 毫秒
1.
双波长紫外分光光度法测定贝母中腺苷和胸苷的含量   总被引:4,自引:0,他引:4  
将4种贝母的甲醇提取物经薄层色谱法粗分离后,直接用双波长紫外分光光度法测定其含量。结果表明,该方法线性关系好,腺苷和胸苷标准曲线的相关系数均为0.9999,同时也发现平贝、炉贝和伊贝中腺苷都占核苷总量60%以上,而浙贝中仅占约40%,提示贝母生药的抗凝血活性可能与贝母中核苷类化合物的种类和含量的差别有关。  相似文献   
2.
Summary. During the course of sterility treatment semenograms of 271 IVF and 316 insemination patients were carried out by two automated semen analysers. The parameters of these analyses were correlated to pregnancies resulting from the treatment. Semen samples were analysed in the ejaculate and after swim-up preparation. In addition, the swim-up suspension of IVF patients was measured again 18 h after sperm preparation. Patients were divided into three groups: (1) couples who achieved a pregnancy, (2) couples who did not achieve a pregnancy, and (3) IVF patients with no fertilization of the oocytes. Because of large standard deviations in the quality of ejaculates, the results in the IVF group show no significant differences in the semen parameters of husbands of pregnant and non-pregnant women. In contrast husbands of women with no fertilization have a significantly lower sperm motility. After swim-up preparation these differences no longer occur. A further measurement, taken 18 h later, reveals that there are no differences in the sperm parameters between the pregnant and non-pregnant group. However, the semen quality in the group with no fertilization is significantly reduced. The results of the insemination patients are similar to those of the IVF group. Thus, the results from automated sperm analysers cannot replace either the microscopic or biochemical analysis of an ejaculate and, moreover, cannot be used as prognosis for the fertilization capacity of sperms or a following pregnancy.  相似文献   
3.
The aim of this study was to determine the relationship between calcium ionophore A23187-induced acrosome reaction (AR) and sperm fertilizing ability. Semen samples remaining after preparation for standard IVF were studied in 109 patients who had sperm concentrations > or =20 x 10(6)/ml. Ionophore-induced AR was performed on motile spermatozoa selected by centrifugation on a Percoll gradient. Semen analysis was performed using standard methods. Patients with higher (>50%, n = 76) fertilization rates had significantly higher ionophore-induced AR than patients with lower (<50%, n = 33) fertilization rates (49 +/- 14 versus 38 +/- 21%, P < 0.05). When the data from all patients were analysed by logistic regression, only the percentage sperm motility in insemination medium and ionophore-induced AR were significantly related to fertilization rates. Similar results were also obtained when the data from a subgroup of patients with poor (<15% normal) sperm morphology were analysed. However, when patients with normal sperm morphology > or =15% were analysed separately, only sperm count and the percentage of spermatozoa with progressive motility in semen were significantly related to fertilization rates. In conclusion, ionophore- induced AR was significantly related to fertilization rates in vitro mainly in patients with teratozoospermic semen. Tests for ionophore- induced AR may provide additional information about sperm fertilizing ability but may not indicate specific defects of the physiological AR.   相似文献   
4.
In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA fragmentation in somatic cells. This study was conducted to ascertain the level of H2O2 concentration within embryos and the morphological features of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31 fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was obtained from the IVF-embryo transfer programme. The relative intensity of H2O2 concentrations within embryos was measured using 2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence imaging and DNA fragmentation was observed with transmission electron microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/- SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed only in fragmented embryos, and was absent in non-fragmented embryos. Electron microscopic findings confirmed apoptotic bodies and cytoplasmic condensation in the fragmented blastomeres. We conclude that there is a direct relationship between increased H2O2 concentration and apoptosis, and that further studies should be undertaken to confirm these findings.   相似文献   
5.
6.
A 9.7 kb segment encompassing exons 7-10 of the adrenoleukodystrophy (ALD) locus of the X chromosome has duplicated to specific locations near the pericentromeric regions of human chromosomes 2p11,10p11, 16p11 and 22q11. Comparative sequence analysis reveals 92-96% nucleotide identity, indicating that the autosomal ALD paralogs arose relatively recently during the course of higher primate evolution (5-10 million years ago). Analysis of sequences flanking the duplication region identifies the presence of an unusual GCTTTTTGC repeat which may be a sequence-specific integration site for the process of pericentromeric- directed transposition. The breakpoint sequence and phylogenetic analysis predict a two-step transposition model, in which a duplication from Xq28 to pericentromeric 2p11 occurred once, followed by a rapid distribution of a larger duplicon cassette among the pericentromeric regions. In addition to facilitating more effective mutation detection among ALD patients, these findings provide further insight into the molecular basis underlying a pericentromeric-directed mechanism for non- homologous interchromosomal exchange.   相似文献   
7.
Human oocytes (n = 380) from 71 in-vitro fertilization patientswere measured 18 h after insemination to find out if certainparameters of oocyte morphology could be related to fertilization.In addition, the number and distribution patterns of spermatozoabound to or within the zona pellucida of 534 oocytes were analysed.The mean diameter of the human oocyte was 167.7 ± 9.5µm and its mean volume was 2.5 x 106 µm3. Therewere no significant differences in diameter between 112 fertilizedand 168 unfertilized oocytes, although they displayed differencesin the size of the perivitelline space and the zona pellucida.The age of the patients had no significant effect on the morphometryof the oocytes. Sperm binding patterns did not correlate withfertilization. The number and distribution of the spermatozoaon the surface of the zona pellucida was extremely heterogeneousand was not related to the occurrence of fertilization. Allpossible binding and distribution patterns were in the samerange in both fertilized and unfertilized oocytes. In conclusion,the micromorphometry of human oocytes and their sperm bindingpatterns were not related to the occurrence of fertilization.  相似文献   
8.
Donor insemination (DI) using cryopreserved semen commenced at The Royal Women's Hospital in 1976. Over the next 15 years we performed 5953 treatment cycles to achieve 816 pregnancies (13.7% per cycle) and 706 live births. In-vitro fertilization (IVF) using donor spermatozoa commenced in 1986. Over the next 5 years we performed 303 treatment cycles for 185 couples. Including subsequent transfer of cryopreserved embryos, a total of 33% of couples achieved a successful pregnancy by IVF. Statistical analysis indicated that, for DI pregnancies, the most important semen variable was the percentage post-thaw motility, whilst for normal fertilization in IVF it was the pre-freeze motility. These results may be explained by the compensatory effects of post-thaw processing of spermatozoa for IVF, but not for DI in our clinic.   相似文献   
9.
下消化道出血221例分析   总被引:4,自引:2,他引:2  
0 引言 下消化道出血是消化科的常见病 ,是指十二指肠空肠移行部 ,屈氏韧带以下的小肠和大肠疾病引起的肠道出血 .有人认为一般不包括痔和肛裂出血 [1 ] .临床最常见为慢性出血 ,但有时出血量大危及生命 ,需要做紧急处理 ,现将我院1992 - 0 1/ 1999- 0 8门诊及病房收治的 2 2 1例下消化道出血进行分析 ,报告如下 :1 临床资料 男 12 0例 ,女 10 1例 ,年龄 14~ 72 (平均 42 )岁 ,病程 16 h~ 10 a.患者分别以脓血便、暗红色血便、鲜血便或果酱色血便为主诉前来就诊 ,其中有休克症状的大出血者6例 .血 Hb<110 g·L- 1 40例 ,<80 g·L- 1…  相似文献   
10.
Human oocytes from the same as well as from different patients have an extremely heterogeneous morphology of the zona pellucida surface as shown by scanning electron microscopy. For years it has been believed that this heterogeneous morphology plays an important part in the sperm-oocyte interaction. It was the aim of this investigation to analyse the morphology and the sperm binding patterns of the human zona pellucida. Oocytes were divided into four categories: mature, immature, fertilized and unfertilized. Four different types of zona morphology were detectable. They ranged from a porous, net-like structure to a nearly smooth and compact surface. No correlation could be established between zona type and oocyte maturity or zona type and achieved fertilization. However, fertilized (polyploid) oocytes had a more compact and smooth zona surface than unfertilized ones. The analysis of the number and distribution patterns of bound spermatozoa on the zona pellucida revealed extremely variable patterns regardless of the zona morphology. Significant differences between mature and immature oocytes did not appear. In both groups there were oocytes with either no or numerous bound spermatozoa on the zona pellucida. Oocytes overloaded with spermatozoa could only be found in the mature group. Unfertilized oocytes had fewer bound spermatozoa on average than polyploid zygotes.  相似文献   
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