发育期大鼠高热惊厥前后海马γ-氨基丁酸B受体亚基表达的变化

目的：研究高热惊厥(febrile seizures，FS)对发育期大鼠脑内γ-氨基丁酸(γ-aminobutyric acid，GABA)B受体亚基GABABR1与GABARR2蛋白表达的影响。方法：采用热水浴诱导大鼠高热惊厥模型。隔日诱导惊厥1次，共诱导10次，末次惊厥后24h处死大鼠。发育期大鼠随机分为3组：对照组(n＝24)，1次高热处理组(n＝28)，10次高热处理组(n＝40)。高热处理组根据是否出现惊厥再分为1次高热惊厥组(FS1，n＝16)与1次高热未惊厥组(F1，n＝12)，10次高热惊厥组(FS10，n＝15)与10次高热未惊厥组(F10，n＝13)。采用免疫组化方法观察不同次数高热惊厥大鼠脑内GABABR1与GABABR2蛋白表达的变化。结果：FS10大鼠海马齿状回、CAl-CA3区GABABRl和GABABR2蛋白表达明显低于F10、F1、FSl和对照组；F10大鼠上述脑区GABABRl和GABABR2蛋白表达低于F1、FS1和对照组；F1及FS1大鼠与对照组相比差异无显著性；海马各区GABABR1与GABABR2表达的改变大部分平行，但10次高热惊厥后GABABR2在CA1—CA3区下降更明显，而GABABR1在齿状回下降更明显。结论：反复高热惊厥及反复高热均可使发育期大鼠脑内GABABR亚基蛋白表达降低，高热惊厥的影响较单纯高热更为明显，提示GABABR亚单位与发育期大鼠高热惊厥及其脑损伤密切相关。GABABR1与GABABR2改变的不平行可能与受体亚单位组合的可塑性改变有关，这种改变可能导致抑制功能的改变。     

Formation of mitochondrial phospholipid adducts by nephrotoxic cysteine conjugate metabolites.

Nephrotoxic cysteine conjugates derived from a variety of halogenated alkenes are enzymatically activated via the beta-lyase pathway to yield reactive sulfur-containing metabolites which bind covalently to cellular macromolecules. Mitochondria contain beta-lyase enzymes and are primary targets for binding and toxicity. Previously, mitochondrial protein and/or DNA have been considered as molecular targets for cysteine conjugate metabolite binding. We now report that metabolites of nephrotoxic cysteine conjugates form covalent adducts with rat kidney mitochondrial phospholipids. Rat kidney mitochondria were incubated with the 35S-labeled conjugates S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (TFEC), S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine (CTFC), S-(1,2-dichlorovinyl)-L-cysteine, and S-(1,2,3,4,4-pentachlorobutadienyl)-L-cysteine. Quantitation of metabolite binding to whole mitochondria and to mitochondrial protein and lipid fractions revealed that as much as 42% of the 35S-label associated with the mitochondria was found in the lipid fraction. Total lipids were also extracted from 35S-treated mitochondria and separated by thin-layer chromatography. 35S-Containing metabolites were found in the lipid fractions from mitochondria treated with each of the conjugates. Lipids from both [35S]CTFC- and [35S]-TFEC-treated mitochondria contained major 35S-labeled lipid adducts which had similar mobility by thin-layer chromatography. Fatty acid analysis, 19F and 31P NMR spectroscopy, and mass spectrometric analyses confirmed that the major TFEC and CTFC adducts are thioamides of phosphatidylethanolamine.     

Effect of maternal and infant covariates on sibship correlation in birth weight

Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.     

大鼠感染性脑损伤中神经细胞内游离钙的变化

采用荧光法测定负载Ｆｕｒａ－２／ＡＭ大脑皮层突触体内游离钙「Ｃａ＾２＋」ｉ浓度大鼠感染性脑损伤中的变化及其意义。     

Antigenicity of a synthetic peptide from glucosyltransferases of Streptococcus mutans in humans.

Human salivary immunoglobulin A (IgA) and serum IgG antibodies to the Streptococcus mutans glucosyltransferases (Gtfs) and to a synthetic peptide of 19 amino acids from a conserved region in the Gtfs (residues 435 to 453) were determined in young adults by enzyme-linked immunosorbent assay. Varying levels of antibody to Gtfs were detected in saliva or serum, with significantly higher levels of antibody to GtfD than to GtfB/C or GtfC. Anti-Gtf IgA levels in saliva did not correlate with those of IgG in serum. Caries-free (CF) volunteers exhibited significantly higher salivary IgA antibody levels to the peptide and to GtfB/C or GtfC than did the caries-active (CA) subjects. Preincubation of CF saliva and serum with the peptide inhibited the antibodies to the Gtfs in a dose-dependent manner, whereas preincubation of the samples from the CA group resulted in only partial inhibition. Our results indicated that this 19-amino-acid peptide includes one of the major B-cell epitopes of Gtfs and that CF individuals have higher titers of antibodies than CA subjects.     

棕榈油对成人血脂和血小板功能的影响

报道了棕榈油（ＰＡ），花生油（ＰＥ）对血清总胆固醇水平（ＴＣ）在５．５～７．０ｍｍｏｌ／Ｌ的受试者血脂和血小板功能的影响。５１名受试者（男３１人，女２０人，年龄３０～６６岁之间）分为两组，一组男１５人，女１１人，称ＰＥ组；另一组男１６人女９人，称ＰＡ组，预备期３周，膳食以当地日常食用的花生油烹调，实验期６周。ＰＡ组受试者食用以棕榈油烹调的实验膳；ＰＥ组受试者仍食花生油烹调的膳食。脂肪约占膳食能量的３０％，其中６０％～６５％来自实验油。实验结果表明：与起始值相比，６周末ＰＡ组受试者血清ＴＣ，低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）和总胆固醇与高密度脂蛋白胆固醇比值（ＴＣ／ＨＤＬ－Ｃ）显著下降，血浆血栓素Ｂ２（ＴＸＢ２）／６－酮前列环素Ｆ１α、（６－ｋｅｔｏ－ＰＧＦ１α）比值显著下降，全血血小板聚集率未见显著变化。ＰＥ组受试者的血脂、血浆ＴＸＢ２、６－ｋｅｔｏ－ＰＧＦ１α及全血血小板聚集率等指标均未出现显著变化。提示，棕榈油作为我国居民家庭烹调用油并不会增加发生心血管疾病的危险。     

体外循环对TXB2／6—keto—PGF1α的影响

对１３例体外循环病人进行了观察，发现体外循环后ＴＸＢ２／６－ｋｅｔｏ－ＰＧＦ１α显著增高，表明体外循环使血小板受损，而血小板受损是体外循环后失血的主要原因之一。     

Hydroxylation of chlorzoxazone as a specific probe for human liver cytochrome P-450IIE1

Human cytochrome P-450IIE1 has been implicated in the oxidation of a number of substrates, including protoxins and -carcinogens. To date, no drugs have been identified that are exclusive substrates for the protein and are applicable for use as noninvasive probes of the in vivo function of the enzyme in humans. Chlorzoxazone was found to be oxidized only to 6-hydroxychlorzoxazone in human liver microsomes. Results of steady-state kinetics are consistent with the view that only a single enzyme catalyzes the reaction. The microsomal reaction was strongly inhibited by rabbit anti-P-450IIE1 and, in a competitive manner, by known P-450IIE1 substrates. Rates of chlorzoxazone 6-hydroxylation in different human liver microsomal preparations were well correlated with levels of immunochemically measured P-450IIE1 and rates of (CH3)2NNO oxidation. Chlorzoxazone 6-hydroxylation was also found to be catalyzed by purified human liver P-450IIE1. These results provide strong evidence that P-450IIE1 is the primary catalyst of chlorzoxazone 6-hydroxylation in human liver. Rates of chlorzoxazone 6-hydroxylation vary considerably among human liver samples, and chlorzoxazone 6-hydroxylation may have potential use as a noninvasive probe in estimating the in vivo expression of human P-450IIE1 and its significance as a risk factor in the toxicity and carcinogenicity of a number of solvents, nitrosamines, and drugs.     

慢性中耳炎的HRCT诊断

探讨慢性中耳炎的ＨＲＣＴ征象，诊断及鉴别诊断。材料与方法；对手术证实的１７例慢性中耳炎患者术前进行ＨＲＣＴ扫描并与手术病理结果对照分析。结果；胆脂瘤８例表现为中耳腔内团块状影，周围低密度环包绕，听骨明显破坏及鬓 扩大，骨缘硬化。４例肉芽肿多呈片状，条索状或网状，听骨破坏较轻。