Factors affecting the metabolic control of cytosolic and lysosomal glycogen levels in the liver

Rats with a gentic deficiency of phosphorylase kinase have been treated with the 1,4--glucosidase inhibitor, Acarbose. Lysosomal glycogen metabolism has been markedly altered and the results support the concept of a feedback control mechanism operating on the uptake mechanism into the lysosomal compartment.     

Anti-MHC immunity detected prior to intentional alloimmunization

Cell fusion was performed between spleen cells from young BALB/cBy (H-2 ^d) mice which have never been immunized and SP2/0 mouse plasmacytoma cells. A monoclonal H-2-specific cytotoxic IgM antibody was obtained (By-1) which detected a new public biregional H-2 specificity, H-2.m210. The mcAb By-1 reacted strongly with H-2K^d, D^d, and H-2^s antigens, gave weak cross-reactions with H-2K^k, D^q, H-2^r, and H-2^v antigens and was negative with H-2^b, H-2^f, H-2^p, and H-2L^d antigens. A polymorphic reaction pattern was also observed on a panel of lymphocytes from B 10.W strains. The intriguing finding on this reaction pattern was the reactivity on H-2^d cells, including the syngeneic BALB/cBy and truly autologous cells. As shown by capping and immunoprecipitation experiments on H-2^d cells and by studies on H-2^d-transfected mouse L cells, the target molecules for McAb By-1 were H-2K^d and H-2D^d molecules. The BALB/cBy mouse, from whose spleen cells the McAb By-1 was obtained, survived after the fusion experiment, and serum was examined for the presence of cytotoxic H-2-specific antibodies during the rest of its life. At the time of the fusion, no autoreactive serum antibodies were found, but about 4 months later, we found in the serum of this mouse autoreactive H-2-specific cytotoxic IgM antibodies. The serum antibodies followed the same reaction pattern as that of the McAb By-1. As far as we know, this is the first report of autoreactive H-2-specific antibodies in serum of a mouse which has never been immunized and of the first natural autoreactive H-2-specific monoclonal antibody.Abbreviations McAb monoclonal antibody - MHC major histocompatibility complex - H-2 major histocompatibility complex of mice - CTLs cytotoxic T cells - FMF flow microfluorometry - FITC fluorescein isothiocyanate - LPS lipopolysaccharide W.E. coli 0111:134 - PBS phosphate-buffered saline - Iodogen 1,3,4,6,-tetrachloro-3,6-diphenylglycoluril - GAMIg goat-antimouse immunoglobulin - Staph-A Staphylococcus aureus Cowan I     

中国下盾螨属一新种及一新纪录：（蜱螨亚纲：厉螨科）

本文记述采自北京的下盾螨属Hypoaspis一新种——钳颖下盾螨Hypoaspis(Holostaspis)chelaris sp.nov.,并报道喀氏下盾螨H.(Geolaelaps) kargi Costa在我国首次发现。     

Improved processes for the production and isolation of dynemicin A and large-scale fermentation in a 10000-liter fermentor

Summary Supplementing the culture ofMicromonospora chersina sp. nov. No. M956-1 with NaI (0.5 mg/l) enhanced the production of dynemicin A by 35-fold in shake flask culture. Homogeneous dynemicin A was obtained from the whole broth extract by Dicalite chromatography, Sephadex LH-20 chromatography and vacuum liquid chromatography. Gram quantities of dynemicin A were obtained from the fermentation ofM. chersina sp. nov. No. M956-1 in a 10000-liter fermentor.     

Gender in bioethics: theory and practice -- an introduction

Does the care perspective make a difference? Can it reach as far as we would like? It is the goal of this special issue on Gender in Bioethics: Theory and Practice to begin to address some of these important questions. In the first article, Virginia Sharpe provides a comprehensive and thoughtful analysis of how the orientations of justice and care are played out in medical ethical theory. In the second article, James Nelson argues that the more traditional approach in Bioethics to maternal-fetal conflicts is not useful, and that a care perspective is more appropriate. Thoughtful commentary on Nelson's article is provided by Rosemarie Tong. For readers new to the justice-care debate in moral theory, the following articles will provide an informative introduction. For those who are more familiar, it is hoped that you will be challenged by the extension of the debate to the practical issue of maternal-fetal conflicts.     

家兔油酸型呼吸窘迫综合征呼吸运动变化的机制

本文介绍家兔实验性呼吸窘迫综合征时呼吸功能的变化。静脉注射油酸后呼吸频率迅速增加,肺通气量则经历三个时相的变化,依次为最初通气增大期、延迟通气增大期和通气不足期。胸廓呼吸运动的幅度随着时间的延长逐渐加大而潮气量则逐渐减少。O_2吸收率及 CO_2排出率在通气不足期显著减少。血气分析提示,在通气增大期有呼吸性碱中毒,至通气不足期出现酸中毒。动脉血 PO_2在注射油酸后20min 时尚能维持在80mmHg 左右,以后则明显下降。切断双侧迷走神经后再注射油酸,呼吸不再增快,最初通气增大期显著减弱,而延迟通气增大期和通气不足期照常发生。切断双侧窦神经后再注射油酸,仍见呼吸加快和最初通气增大期,但延迟通气增大期消失。上述结果表明:动物注射油酸后,呼吸加快和最初通气增大期是通过迷走神经实现的,而延迟通气增大期则是由于缺 O_2,刺激外周化学感受器所致。     

Isolation of rat hepatocytes with EDTA and their metabolic functions in primary culture

Summary Isolated hepatocytes from adult rat liver were prepared after dissociation of the liver with EDTA. The morphological appearance, viability (94.5%) and yield (1.76.10⁷ cells/g liver) compare well with those of previously described methods using collagenase. Differentiated functions of the hepatocytes in primary culture such as albumin secretion (10.9 μg/mg cell protein/d) and triglyceride synthesis and secretion are maintained. Induction of triglyceride synthesis and secretion by oleic acid takes place to an extent similar to that observed in vivo and liver perfusion. Particles with a lipid composition resembling circulating very low density lipoproteins are secreted into the medium. These characteristics demonstrate the ability of hepatocytes isolated with EDTA and subsequently used in primary culture to retain complex and highly differentiated functions of the intact liver.     

Characterization of protease production by a type-III group-BStreptococcus

A type-III group-B streptococcus (Streptococcus agalactiae) isolated from a case of late-onset sepsis was examined for protease production. In broth culture, extracellular proteolytic enzymes were not detected until the late exponential phase of growth with maximal protease production occurring during the stationary phase. Three distinct protease pools were isolated from the supernatant fluids of stationary-phase cultures, employing a combination of ion-exchange chromatography and gel-filtration chromatography. One population of proteases (containing two protease pools separable by gel filtration chromatography) eluted from a diethylaminoethyl cellulose column at a sodium chloride gradient concentration of 0.15M while a second population eluted from the same material at a sodium chloride concentration of 0.35M. These protease pools varied in molecular weights from approximately 25,000 daltons to 160,000 daltons as determined by gel filtration on Sephadex G-200. All three protease preparations had pH optima of 8.0–9.0, and all were active against gelatin, human serum albumin, and casein, but were not active against elastin or collagen. In addition, all three protease preparations completely inactivated purified type-III group-B streptococal neuraminidase. The role of these proteases in the disease process caused by the type-III group-B streptococci must remain speculative at this time.     

Effect of allopurinol on the utilization of purine degradation pathway intermediates by tobacco cell cultures

Suspension cultured Nicotiana tabacum (tobacco) cells grow slowly on intermediates of the purine degradation pathway (hypoxanthine, xanthine, uric acid, allantoin, and urea) as their sole nitrogen source indicating that this degradation pathway is operative in these cells. The hypoxanthine analog, allopurinol inhibited tobacco cell growth on hypoxanthine but not uric acid. This helps confirm that the site of action of allopurinol is the conversion of hypoxanthine to uric acid by xanthine oxidase. Attempts to select cells which could grow in the presence of allopurinol with hypoxanthine as the nitrogen source were not successful.