抗心律失常肽在大鼠肾内的分布

应用免疫组织化学ＰＡＰ技术，研究了抗心律失常肽（ＡＡＰ）在大鼠肾内的分布，结果表明：ＡＡＰ样细胞分布于皮质与髓质交界处近端小管、远端小管和集合小管壁，也分布于髓质深部集合小管壁，但皮质和髓质浅部未见到免疫反应细胞。肾内ＡＡＰ可能与肾小管和集合小管的分泌和重吸收功能有关。     

人工髓核材料(半晶聚乙烯醇水凝胶弹性体)的研制

研制一种可替代椎间盘髓核并恢复其功能的生物医用材料 ,探讨半晶聚乙烯醇水凝胶弹性体材料临床应用的可行性。聚乙烯醇 (PVA)水溶液在 - 2 0℃下冷冻 6～ 12 h,室温下融化 1～ 2 h,上述过程重复 1～ 3次 ,然后对试样进行真空脱水 ,制得人工髓核材料 (半晶 PVA水凝胶弹性体 )。差示扫描量热法 (DSC)和力学性能试验研究了 PVA水溶液浓度、真空脱水和 γ射线辐照对水凝胶 PVA的结晶度和力学性能的影响     

羧甲基壳聚糖作为植入可降解缓释微球辅料的实验研究

羧甲基壳聚糖作为一种高分子材料 ,具有良好的组织相容性和生物可降解性。本实验试图利用羧甲基壳聚糖作为植入环丙沙星微球的缓释辅料 ,并探索这一剂型的制备工艺、结构形态和体外释药特性。首先我们采用乳化交联技术制备微球 ;然后用扫描电子显微镜、红外光谱、及示差热分析等方法研究微球的结构和形态 ;建立体外持续流动释放系统初步检测微球的体外释放特性。实验结果发现 :微球的结构和形态受制备工艺条件如温度、离子强度、搅拌速度等因素的影响 ;一定工艺条件下制备的环丙沙星微球的体外释放时间可达 7d以上 ,释放行为符合 Higuchi方程。因此 ,我们认为 :羧甲基壳聚糖可作为环丙沙星可降解植入微球的缓释辅料 ;乳化交联技术是制备这一微球的有效方法 ,工艺简单、稳定     

微粒子化学发光免疫测定促甲状腺素敏感性方法的建立与应用

目的 :建立一种低成本、高敏感性检测血清促甲状腺激素(TSH)的微粒子化学发光免疫分析 (CLEIA)方法。方法 :采用碱性磷酸酶标记的抗TSHβ亚单位特异性单克隆抗体 (mAb) ,与FITC偶联的抗TSHα亚单位的另一mAb配对 ,构成双抗体夹心免疫结合 ,用抗FITC多抗免疫磁珠做固相分离载体 ,用金刚烷胺CSPD为发光底物的非均相免疫分析法。结果 :方法灵敏度 4 μIU/L ,批内变异系数 (CV)平均为7.4 5 % ,批间CV平均为 10 .4 5 % ,回收率为 91.4 %～ 10 2 .4 %。将实际样品测定与ACS 180  系统检测的结果相比较有较好的相关性。结论 :微粒子化学发光定量测定TSH的成本低、灵敏度及特异性高和稳定性好 ,具有广阔的应用前景     

Auditing concept categorizations in the UMLS

The Unified Medical Language System (UMLS) integrates about 880,000 concepts from 100 biomedical terminologies. Each concept is categorized to at least one semantic type of the Semantic Network. During the integration, it is unavoidable that some categorization errors and inconsistencies will be introduced. In this paper, we present an auditing technique to find such errors and inconsistencies. Our technique is based on an expert reviewing the pure intersections of meta-semantic types of a metaschema, a compact abstract view of the UMLS Semantic Network. We use a divide and conquer approach, handling differently small pure intersections and medium to large pure intersections. By using this approach, we limit the number of concepts reviewed, for which we expect a high percentage of errors. We reviewed all concepts in 657 pure intersections containing one to 10 concepts. Various kinds of errors are identified and the analysis of the results are presented in the paper. Also, we checked the pure intersections containing more than 10 concepts for their semantic soundness, where the semantically suspicious pure intersections are presented in the paper and their concepts are reviewed.     

Neural tube defects and vitamin B12: a report of three cases

Periconceptional folic acid supplementation reduces the frequency of embryological neural tube defects (NTD). This fact led the USA to fortify grain products with folic acid (140 microg/100 g) starting in January 1998, with a resultant decrease in the incidence of NTD. Folate deficiency is thus confirmed to be a risk factor for NTD. However, in a prospective study, we investigated three women who conceived a fetus with NTD; no folate deficiency was found in these women but all three had decreased vitamin B12 levels (cobalamin), which can be an other risk factor. Samples were obtained from two women in Algeria, 2 days after interruption of pregnancy, and from a vegetarian woman, in France, one month after interruption of pregnancy. Red cell folate and plasma folate, vitamin B12, B6 and homocysteine were assayed and the mutations C677T (in metylenetetrahydrofolate reductase gene), A2756G (in methionine synthase gene) and A66G (in methionine synthase reductase gene) were sought. Elevated plasma folate levels were found in both Algerian women. Vitamin B 12 levels in all three women were decreased or in the lowest quartile of normal values. One woman presented simultaneously a vitamin B 12 deficiency, and heterozygous mutations in the three genes. The second woman presented a A66G homozygous mutation and the third heterozygous C677T and A66G mutations. Acquired and inborn factors are intricated in some cases of pregnancies with NTD and B 12 deficiency can be responsible for intracellular folate cycle failure. It would therefore be advisable to consider fortifying grain products with both folic acid and vitamin B12.     

Association of DAAO with schizophrenia in the Chinese population

Recently, the gene called DAAO was reported to be associated with schizophrenia in the French Canadian populations. Here, we report a result obtained in the study of our large collection of 547 schizophrenia cases and 536 controls in the Chinese population. Six single-nucleotide polymorphisms (SNPs) were genotyped at and around the DAAO locus, covering a 10-kb region entirely encompassing the complementary DNA sequences of DAAO. We found statistically significant differences in allele distributions on one marker: SNP rs3741775 (P = 0.0000001). In the haplotype analysis based on the information of linkage-disequilibrium block across this gene locus, we demonstrated a highly significant association between schizophrenia and a DAAO haplotype (P = 2.0173 x 10(-21)), which therefore provides an independent statistical support for association of the DAAO gene with schizophrenia and indicates that the DAAO gene may play a significant role in the etiology of schizophrenia in the Han Chinese.     

Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11

In a large collaborative screening project, 370 men with idiopathic azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA loci in Yq11. In 12 individuals, we observed de novo microdeletions involving several DNA loci, while an additional patient had an inherited deletion. They were mapped to three different subregions in Yq11. One subregion coincides to the AZF region defined recently in distal Yq11. The second and third subregion were mapped proximal to it, in proximal and middle Yq11, respectively. The different deletions observed were not overlapping but the extension of the deleted Y DNA in each subregion was similar in each patient analysed. In testis tissue sections, disruption of spermatogenesis was shown to be at the same phase when the microdeletion occurred in the same Yq11 subregion but at a different phase when the microdeletion occurred in a different Yq11 subregion. Therefore, we propose the presence of not one but three spermatogenesis loci in Yq11 and that each locus is active during a different phase of male germ cell development. As the most severe phenotype after deletion of each locus is azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable phase of function in human spermatogenesis and candidate genes involved will be discussed.      

Five novel mutations in the L1CAM gene in families with X linked hydrocephalus.

Five novel mutations have been identified in the gene encoding L1CAM, a neural cell adhesion protein, in families with X linked hydrocephalus (XHC). Interestingly, all five mutations are in the evolutionarily highly conserved Ig-like domains of the protein. The two frameshift mutations (52insC and 955delG) and the nonsense mutation (Trp276Ter) most probably result in functional null alleles and complete absence of L1CAM at the cell surface. The two missense mutations (Tyr194Cys and Pro240Leu) may considerably alter the structure of the L1CAM protein. These data provide convincing evidence that XHC is genetically extremely heterogeneous.