O-acetylated peptidoglycan: its occurrence, pathobiological significance, and biosynthesis.

Bacterial cell walls and their structural units, particularly peptidoglycan, induce a vast variety of biological effects in host organisms. The pathobiological effects of peptidoglycan are greatly enhanced by various modifications and substitutions to its basic composition and structure. One such modification is the presence of acetyl moieties at the C-6 hydroxyl group of N-acetylmuramyl residues, and to date, 11 species of eubacteria, including some important human pathogens, such as Neisseria gonorrhoeae, Proteus mirabilis, and Staphylococcus aureus, are known to possess O-acetylated peptidoglycan. This review addresses the influence of O-acetylation of peptidoglycan on its resistance to degradation both in vitro and in vivo, the clinical importance of the modification, and the currently held views on the pathway for its biosynthesis.     

British National Formulary: its birth,death, and rebirth.

The British National Formulary is a direct descendant of the National War Formulary, in which the titles of the preparations were in Latin and the doses in minims and grains. The British National Formulary was born in 1948, did a good job for about 20 years, but sickened and died in 1976. It was reborn in 1981. Parturition was painful with a very hostile reception from the media and the drug industry, but it survived and has grown in stature. The 25th edition was published in February. Wish it well for the next 25 issues!     

Clinical fever: its history, manifestations and pathogenesis.

A short summary of some aspects of the history of clinical fever is presented with special reference to its association with inflammation. The role of bacterial endotoxins and endogenous pyrogen (released from inflammatory cells) in the genesis of human fevers is reviewed. Clinical diseases are tabulated within various broad categories and discussed in relation to the frequency with which they are associated with fever and the probable pathogenetic mechanisms involved. Certain unresolved discrepancies are emphasized in the light of our present knowledge.     

Twin research, and its multiple births and expressions: a short, personal voyage through its scope, history, and organization.

The notion of twins and twinning involves a multiplicity of meanings and contexts that altogether encompass an unexpectedly wide and significant part of human experience, culture, and endeavor. This cultural polysemy is, to some extent, also an attribute of twin research, which has structured itself around a multiplicity of scientific areas of enquiry, and across time, throughout a multiplicity of births and rebirths, periodically declining and resurging as a phoenix from its ashes. What is proposed is a short voyage through this polysemy and phoenixity of twinning and twin research, and through the structuring process that has accompanied its developments, international scope, and organization. No claim to completeness, but an attempt to dig into personal memory and experience, and share some recollections of the main steps of the process, and particularly the evolution of the journal, the society, the international meetings, and their role in supporting the area's persistence and continuous revivals and adaptations until today.     

雷击火发生的影响因子与预测研究进展

雷击火是最重要的自然火源,由此引发的森林火灾给人类和生态环境都带来了巨大损失,各国都非常重视对其预测研究.本文以影响雷击火形成的主要因素为切入点,着重分析了云地闪特征、可燃物、气象和地形4个因素对雷击火形成、发展的影响及作用机理;在此基础上,对雷击火预测研究中广泛使用的Logistic模型、K-函数等数学方法进行总结和评述,并对美国、加拿大的雷击火预测方法和流程进行介绍,最后对以往研究中的不足之处提出了探讨性的解决方案,并对未来的研究内容和趋势进行了分析,以期对我国的雷击火预测工作提供必要的理论依据和文献参考.     

Rabbit lutropin: preparation, characterization of the hormone, its subunits and radioimmunoassay.

The purification of rabbit lutropin is described. A product with a potency of 1.53 X NIH-LH-Sl was obtained as assayed by the ovarian ascorbic acid depletion assay. In a homologous radioimmunoassay, which is described, rabbit lutropin has a potency 4.83 X NIH-LH-Sl. In a radioligand assay, utilizing labeled ovine lutropin as the trace, the relative potency was 0.47 X NIH-LH-Sl measured by 50% inhibition comparison since rabbit lutropin response in this system did not parallel ovine lutropin. A counter-current distribution procedure for separation of rabbit lutropin subunits is described. Amino acid composition of the isolated subunits and intact rabbit lutropin was determined. The carbohydrate composition of the latter is presented; only amino sugar determinations are available for the subunits. The NH2-terminal amino acids are phenylalanine (alpha subunit) and alanine (beta subunit). Preliminary data on COOH-terminal amino acids are provided.     

Body weight: its relation to tissue composition, segment distribution, and motor function. I. Interspecific comparisons.

The composition of skin, muscle, and bone and their distribution throughout the body are compared for "advanced" or "specialized" species (Alouatta, Macaca, Canis, Felis, Lepus); smaller, more closely related species (Tupaia and the Lorisidae); and several species within the same ecosystem (Barro Colorado Island, Panama). Among the most significant variables, the skin of sloths, howlers and macaques constitutes more than 12% of body weight, whereas greyhound skin is 5% of weight; sloth and howler muscle are 25% of weight, macaque muscle about 40% of weight, greyhound and agouti muscle over 50% of weight. In tree shrews and galagos muscle is heavier (35%) than in pottos and slow lorises (below 28%), but bone and skin are lighter. All species differ in the segmental distribution of weight. Cats have light tails, light feet and heavy thighs, whereas howlers have heavy tails, heavy feet, and light thighs. The galagos have heavy hindlimbs and tails, the pottos and lorises have reduced tails and approximately equal fore- and hindlimbs. Convergences in segment pattern (sloths with pottos and lorises, marmosets with tree shrews, owl monkeys with galagos, cebus with macaques) as well as divergences are documented. All weight-of tissue and weight-of-segment variables are correlated directly with locomotor adaptation.