The physical state of alkali ions in a Halobacterium: some NMR results

The 46th case of known pregnancy-induced pancytopenia is reported. Pregnancy may play an etiologic role in this rare condition, but the specific mechanism is unknown. Maternal mortality is 63%, and fetal and neonatal wastage is 46%. The patient reported is a 24-year-old Oriental woman who delivered a healthy female infant. Her survival is attributed to conservative management with carefully timed packed cell and platelet transfusions.     

采用层次分析法(AHP)综合评价轧制油(Ⅰ)——层次分析法简介

在国内外首次引入层次分析法 (AHP)对轧制油进行评价和综合排序 ,解决了金属加工用润滑剂涉及油品及工艺润滑性能指标较多 ,选择最佳润滑剂困难的问题 ,而且工业应用表明AHP法是非常有效的。这也为今后科学合理地选择润滑剂提供了一条捷径。第一部分重点介绍了层次分析法 (AHP)及其应用。     

A single mouse glutathione synthetase gene encodes six mRNAs with different 5' ends

To understand more about the role of glutathione (GSH) in metabolism, we have cloned both cDNA and genomic sequences for mouse glutathione synthetase (GSH syn), the enzyme that catalyzes the last step in the synthesis of glutathione. The mouse cDNA contains an open reading frame (ORF) of 474 aa and shares 64 and 95% deduced amino acid sequence identity with Xenopus cDNA and rat cDNA, respectively. The cDNA complements Schizosaccaromyces pombe strains deficient in GSH syn. The gene is a single-copy gene spanning approximately 30 kb and is composed of at least 15 exons. Steady-state RNA levels and enzyme activity levels are highest in kidney, about 3-fold lower in liver, and 8- to 10-fold lower in lung and brain. We have identified six different GSH syn RNAs: three, termed types A1, A2, and A3, have different 5' ends that localize to different sites in the gene, but appear to encode the same protein (474 aa). Types B, C1, and C2 all have unique 5' ends and type-specific ORFs, which are shorter than that for types A1, A2, and A3. In liver only type A1 GSH syn RNA is detectable, while in kidney 90% of GSH syn RNA is type A1 and types B and C account for about 10%.     

Regulation of vascular endothelial growth factor (VEGF) expression is mediated by internal initiation of translation and alternative initiation of transcription

The growing amount of high quality molecular dynamics simulations generated using the latest methodological developments and force fields has led to a sharper understanding of the forces underlying the dynamics of biomolecular systems, as well as to stimulating insights into the structure and catalysis of nucleic acids. It is now clear that inclusion of long-range electrostatic interactions and of the aqueous and ionic environment is necessary for producing realistic and accurate simulations. Yet, many papers hint at a force field and protocol dependence of the results and thus contain the seeds for the future improvements that will be necessary for deepening our understanding of recognition phenomena and folding of nucleic acids.     

植物油厂废水处理工艺及设备的研究

论述了植物油厂的废水来源和废水处理的工艺效果，分析和研究了主要废水处理设备的结构，工作原理和效果。     

Anticonvulsants and congenital malformations

Earlier studies indicated that the prevalence of congenital anomalies is greater in infants of epileptic mothers treated with anticonvulsants than in infants of mothers without epilepsy. We carried out a study of women in the General Practice Research Database who delivered liveborn infants between January 1988 and March 1993 and who were exposed to an anticonvulsant drug during the first trimester of pregnancy, and women with epilepsy not treated with anticonvulsants during pregnancy. We matched two nonexposed women without epilepsy to each exposed woman for age at delivery, date of baby's birth, and general practice. Two hundred ninety-seven women treated for epilepsy had 10 liveborn infants with major anomalies (3.4%) compared with 6 of the 594 nonexposed women (1.0%, RR = 3.3, 95% CI 1.2-9.2). We conclude that the infants of women with epilepsy who are treated with an anticonvulsant during the first trimester of pregnancy have an increased risk of major congenital anomalies.     

Xylitol, a partial homologue ot alpha-D-glucopyranose: potent stimulator of insulin release in dogs

A direct comparison was made in healthy female dogs of the potency of xylitol and mutarotated glucose as stimulators of insulin release (both first and second phases), and also of their urinary excretion and arterio-venous difference across a hind-limb. Xylitol or glucose was given by constant infusion into a systemic vein for 50 minutes in paired experiments. Three dose levels were used in 12 dogs. Plasma insulin levels during xylitol infusion were as high as or higher than those during glucose infusion, with increases in arterial xylitol levels equal to or less than those in glucose. More xylitol was lost in the urine, but the overall uptake of xylitol was at least 70% also the arteriovenous difference for xylitol across the hind-limb was greater than for glucose, when each was divided by the arterial sugar concentration. It is suggested that both the striking potency of xylitol in stimulating both phases of insulin release, and its rapid uptake by tissues, may result from its homology with alpha-D-glucopyranose, the alpha-anomer of glucose. The concept of a glucoreceptor on the surface of the pancreatic beta-cell, with stereospecificity for alpha-D-glucopyranose or closely similar molecules, is supported by our results.     

Chemical studies on actinoxanthin

The antitumor protein actinoxanthin exhibits high inhibitory activity against a number of gram-positive bacteria and some strains of transplantable leucoses and related tumors. Actinoxanthin was shown to consist of a single polypeptide chain crosslinked by two disulfide bonds and to contain 107 amino acid residues. Reduced and alkylated actinoxanthin was digested with chymotrypsin, thermolysin and trypsin. Based on the sequence analysis of fragments so obtained the complete amino acid sequence and the location of disulfide bonds of actinoxanthin has been proposed. The high degree homology of some regions of actinoxanthin and the antitumor protein neocarzinostatin have been revealed.