Endothelial nitric oxide synthase gene polymorphism in women with idiopathic recurrent miscarriage

BACKGROUND: Lack of endothelium-derived nitric oxide is associated with vasospasm and vascular infarction. We investigated the relationship between idiopathic recurrent miscarriage and a polymorphism of the gene encoding endothelial nitric oxide synthase (NOS3). METHOD: In a prospective case-control study, 105 women with idiopathic recurrent miscarriage and 91 healthy controls were investigated. We used the polymerase chain reaction to identify the different alleles of a 27 base pair tandem repeat polymorphism in intron 4 of the NOS3 gene. RESULTS: The wild type B allele was identified on 329 out of 392 chromosomes (frequency 0.84). The polymorphic A allele was present on 63 chromosomes (frequency 0.16). The genotype frequencies were as follows: 68% (B/B), 31% (A/B) and.5% (A/A). The distribution of genotype frequencies was significantly different between the study and control groups for allele A/B heterozygotes (NOS3(A/B)) (36.7 versus 23.8%, P = 0.03, OR 1.6, 95% CI 1.1--3.8). Only one individual was homozygous for the A allele (NOS3(A/A)). She was in the study group. Between women with primary and secondary recurrent miscarriages, no statistically significant difference between the distribution of NOS3(A/B) genotypes (28 versus 34%) was observed. CONCLUSIONS: These data support a role for the NOS3 gene as a genetic determinant of the risk of idiopathic recurrent miscarriage.     

Nitric oxide (NO) in expired air at rest and during exercise

Nitric oxide (NO) was analysed in expired air from 27 healthy human subjects. At rest the NO concentration was 10.5 ± 0.9 ng 1^-1 (mean ± SEM) corresponding to 8.6 ± 0.7 parts per billion (ppb). The expired NO concentration did not change when the subjects were switched from breathing NO-free tank gas to room air which contained 7.7 ng 1^-1 NO. Repeated measurements of expired NO with an interval of 1 day showed a mean variation of 2.2 ± 0.7ngl^-1 NO. The NO concentration in the first portion in the expired tidal volume (44%) was insignificantly higher than in the latter expired portion, 6.9 ± 1.9 vs. 5.1 ± 1.0 ng 1^-1 (n= 5). During moderately heavy exercise on an ergometer bicycle (90 W for women, n= 4, 150 W for men, n= 4) the expired concentration of NO decreased, however because of increased minute ventilation, the expired amount of NO almost doubled (from 111 ± 12 to 209 ± 30 ng min^-1). The source of the expired NO is not clear and both the airways and the pulmonary circulation may contribute.     

广东汉族人蛋氨酸合成酶基因多态性

目的了解广东汉族人蛋氨酸合成酶基因的分布特点.方法应用聚合酶链反应技术对211例正常人蛋氨酸合成酶基因进行扩增,进行图谱分析.并结合文献进行了不同种族间的分析比较.结果广东汉族人群中MS基因型以AA最多见,AG次之.AA基因型频率为0.8009、AG为0.1802、GG为0.0189.A基因型频率为0.8910、G为0.1090.与其他种族相比较,MS基因型在中国正常人群中的分布与白种人群中的分布差异显著.结论蛋氨酸合成酶基因因多态性在不同种族间分布存在着明显的差异.     

妊娠特异性β1糖蛋白免疫调节作用的研究

目的:探讨妊娠特异性β1糖蛋白(PSβ1G)免疫调节作用。方法:用L929细胞系作为靶细胞检测巨噬细胞的细胞毒作用。用硝酸还原酶法检测巨噬细胞分泌NO的水平。用MTT比色法检测T细胞的增殖反应。用流式细胞术分析细胞凋亡及细胞周期的变化。结果:PSβ1G能抑制单核巨噬细胞的细胞毒作用,抑制其分泌NO。部分抑制ConA刺激的T细胞增殖反应,使其受阻于G0/G1期。结论:PSβ1G抑制巨噬细胞和T细胞的免疫。     

Further evidence for the alternative pathway of trehalose synthesis linked to maltose utilization in Saccharomyces

Summary Yeast strains bearing a deficiency in trehalose-6-phosphate synthase activity are unable to accumulate trehalose on any carbon source unless they contain one of the MAL genes. If the gene is inducible then synthesis of trehalose occurs specifically during growth on maltose when the MAL gene is constitutive then trehalose accumulation can also be seen when cells are grown on glucose. Different systems for trehalose synthesis were suggested: one of them would require the UDPG-linked trehalose synthase whereas the second would utilize an alternative pathway. We proposed a mechanism by which the gene-product of a MAL gene would serve as a common positive regulator for the expression of the genes coding for maltose permease, -glucosidase and some component of the trehalose accumulation system. In order to elucidate this novel pathway a strain lacking UDPG-linked trehalose synthase activity and harboring a defect in maltose uptake was constructed. Excessive maltose uptake resulted in accumulation of intracellular maltose, and twice as much trehalose as in a control strain. Partial inhibition of hexokinase by xylose affected the ratio between internal maltose and trehalose and significantly reduced glycogen synthesis. Sodium fluoride also blocked glycogen synthesis but allowed for trehalose accumulation. Moreover, a mutant which lacks hexokinase I and II was unable to accumulate trehalose when grown on glucose in spite of the presence of a constitutive MAL2 gene. These results suggest that trehalose synthesis would require G-6-P formation derived from maltose. Such a deviation would allow for slowing down the glycolytic flux which, in turn, would favour efficient maltose utilization. Therefore, trehalose synthesis during growth in media containing glucose serves as an additional parameter for assessing constitutivity of MAL genes.     

褪黑素对睡眠剥夺大鼠记忆的影响

目的探讨褪黑素对睡眠剥夺(SD)大鼠记忆的影响及其机制。方法24只大鼠随机分为对照组(SD 生理盐水)和2个实验组(SD 小、大剂量褪黑素),用小平台水环境法建立大鼠SD模型,SD48h和SD72h后用水迷宫测试大鼠的记忆能力,最后检测大鼠大脑皮层和海马中一氧化氮(NO)和丙二醛(MDA)含量。结果实验组大鼠SD48h和SD72h水迷宫反应时均明显小于对照组(F=11.89、5.44,P=0.00、0.012)。实验组大鼠大脑皮层和海马组织中NO和MDA含量明显低于对照组(F=14.31~27.41,P=0.00)。结论褪黑素对睡眠剥夺大鼠记忆障碍有改善作用,这可能与抑制睡眠剥夺大鼠大脑皮层和海马中NO及MDA的升高作用有关。     

Pulmonary function changes in asthmatics associated with low-level SO2 and NO2 air pollution, weather, and medicine intake

This paper presents the response in subjects with asthma to gaseous air-pollution levels, weather, and medicine intake as identified by principal-component analysis and neutral network techniques. Pulmonary function measured by respiratory peak-flow rate in nonallergic asthmatics was associated with ambient, low level, air-pollution concentrations of sulphur dioxide and nitrogen dioxide, temperature, relative humidity, and medicine intake. Results from 27 nonallergic asthmatics aged 18–60 years with well-characterized bronchial asthma and regular medical treatment were analyzed from two cities. During an 8-month period, each subject kept a diary table, which included symptoms, lung function (evening peak flow), medicine intake, and tobbaco smoking.
High intake of medicine and high ambient temperatures correspondend to decreased peak flow. The changes in temperature did not occur in situations with low medicine intake. During frost periods, peak-flow values decreased independently of medicine intake and levels of so². During other times, increased levels of so² and no² increased temperature, and increased intake of medicine, and low relative humidity corresponded to synergistically to decreased peak flow at levels above 40μ/m³.     

Gibberellin biosynthesis in Gibberella fujikuroi: cloning and characterization of the copalyl diphosphate synthase gene

The gene coding for copalyl diphosphate synthase (CPS), which represents the first gene of the gibberellin pathway, was isolated from the rice pathogen Gibberella fujikuroi. This fungus is used commercially for the production of gibberellic acid and related gibberellins. CPS is a terpene cyclase which catalyzes the first specific step of the gibberellin (GA) pathway as it branches off from the general isoprenoid (biosynthetic) pathway at geranylgeranyl disphosphate (GGDP). A cDNA fragment of the cps gene from the fungus G. fujikuroi was amplified by RT-PCR using oligonucleotides based on amino-acid sequences which were conserved between the plant CPSs and the bifunctional CPS/KS of the fungus Phaeosphaeria sp. L487. A 588-bp fragment obtained with nested PCR was used to isolate the corresponding genomic clone of the cps gene from the wild-type λ-library. This gene consists of three exons and two introns. The three exons are 2877 bp long and encode 959 amino-acid residues. The protein shares 48% identity with the bifunctional Phaeosphaeria sp. L487 FCPS and between 16% and 18% identity to the corresponding plant CPSs. Expression of the G. fujikuroi cps gene is strongly enhanced under conditions optimized for gibberellin biosynthesis and is reduced when high amounts of ammonium are present in the medium. Gene disruption, followed by gibberellin assays and Southern-blot analysis of the transformants, demonstrated clearly that the cloned gene has the expected function in the biosynthesis of fungal gibberellins. Received: 28 April / 1 July 1998     

一氧化氮合酶3基因多态性与复发性早期自然流产的关系

目的探讨一氧化氮合酶3(nitric oxide synthase 3,NOS3)基因第4内含子27bp数目可变串联重复序列(variable number of tandem repeat,VNTR)多态性和第7外显子894(G/T)多态性与复发性早期自然流产(recurrent early spontaneous abortion,RESA)的相关性。方法选取140例RESA患者和140名健康妇女,应用聚合酶链反应-琼脂糖凝胶电泳法检测NOS3基因第4内含子VNTR多态性,聚合酶链反应-限制性片段长度多态性分析技术检测第7外显子894(G/T)多态性。结果RESA组aa ba基因型频率和a等位基因频率与正常对照组相比差异有统计学意义(χ2=4.51,P<0.05;χ2=4.29,P<0.05)。与bb基因型相比,携带a等位基因的妇女与RESA显著相关(OR为1.8,95%CI:1.04~3.24)。RESA组TT GT基因型频率和T等位基因频率与正常对照组相比差异无统计学意义(χ2=1.16,P>0.05;χ2=1.12,P>0.05)。与GG基因型相比,携带T等位基因的妇女与RESA无相关。结论NOS3基因第4内含子27bp数目可变的串联重复序列多态性与复发性自然流产密切相关,NOS3基因第7外显子894G/T多态性与RESA无明显相关性,a等位基因是RESA重要的遗传易感基因。