血红细胞超氧化物歧化酶(SOD)制备工艺的研究初报

本文报告了本实验室设计的由血红细胞自溶液60℃热变性, 乙醇——氯仿法除血红蛋白,旋转蒸发法减压浓缩抽去氯仿、乙醇,硫酸铵分级盐析法沉降SOD,Sepbadex G-75层析提纯SOD等步骤构成的一条成本低、设计合理、简便实用的分离纯化SOD的工艺路线。     

Histological and immunohistochemical effects of Curcuma longa on activation of rat hepatic stellate cells after cadmium induced hepatotoxicity

The liver is a target for toxic chemicals such as cadmium (Cd). When the liver is damaged, hepatic stellate cells (HSC) are activated and transformed into myofibroblast-like cells, which are responsible for liver fibrosis. Curcuma longa has been reported to exert a hepato-protective effect under various pathological conditions. We investigated the effects of C. longa administration on HSC activation in response to Cd induced hepatotoxicity. Forty adult male albino rats were divided into: group 1 (control), group 2 (Cd treated), group 3 (C. longa treated) and group 4 (Cd and C. longa treated). After 6 weeks, liver specimens were prepared for light and electron microscopy examination of histological changes and immunohistochemical localization of alpha smooth muscle actin (αSMA) as a specific marker for activated HSC. Activated HSC with a positive αSMA immune reaction were not detected in groups 1 and 3. Large numbers of activated HSC with αSMA immune reactions were observed in group 2 in addition to Cd induced hepatotoxic changes including excess collagen deposition in thickened portal triads, interlobular septa with hepatic lobulation, inflammatory cell infiltration, a significant increase in Kupffer cells and degenerated hepatocytes. In group 4, we observed a significant decrease in HSC that expressed αSMA with amelioration of the hepatotoxic changes. C. longa administration decreased HSC activation and ameliorated hepatotoxic changes caused by Cd in adult rats.     

Metabolic risks at birth of neonates exposed in utero to HIV-antiretroviral therapy relative to unexposed neonates: an NMR metabolomics study of cord blood

Introduction

Antiretroviral therapy (ART) for HIV-infected pregnant women is highly effective in preventing mother-to-child transmission (PMTCT) of the virus, but deleterious metabolic and mitochondrial observations in infants born to HIV-infected women treated with ART during pregnancy are periodically reported.

Objectives

This study addresses the concern of HIV-ART-induced metabolic perturbations through a metabolomics study of cord blood collected during transitional neonatal hypoglycaemia following birth from newborns either exposed or unexposed to fetal HIV-ART.

Methods

Proton magnetic resonance spectra from cord blood of 11 in utero HIV-ART-exposed and 14 unexposed newborns, as well as serum from 8 control infants, generated 114 spectral bins which were used to identify significant metabolites by means of univariate and multivariate statistical analyses.

Results

The metabolite profiles differed significantly between that from the unexposed newborns and that from infants—interpreted to characterize the state of transitional neonatal hypoglycaemia (low glucose and high lactic acid and ketone bodies). Quantitative analysis of potential ATP generation showed no meaningful difference in the global metabolite profiles of HIV-ART-exposed and unexposed neonates, but Volcano plot analysis, affirmed by odds ratios, indicated that exposure to HIV-ART affected the plasma 3-hydroxybutyric acid and hypoxanthine concentrations.

Conclusions

The metabolite profile for transitional neonatal hypoglycaemia indicated that HIV-ART did not compromise the exposed neonates to the energy stress of allostasis experienced at birth. Increased hypoxanthine and 3-hydroxybutyric acid indicates metabolic stress at birth in some of the newborns exposed to HIV-ART and raises a concern about unrecognized prolonged allostasis with potential neurological consequences for these infants.

     

Role of monovalent cations in fluid secretion from the exocrine rabbit pancreas

The role of Na+ in fluid secretion by the isolated rabbit pancreas was investigated. The fluid secretion rate is reduced upon replacement of Na+ in the bathing medium by Li+, K+ or choline. The inhibition depends on the nature of the substituting cation, and is largest with choline. Upon replacement, the substituent cation appears in the secreted fluid, and the Na+ concentration in the secreted fluid is decreased in a mirror-like fashion. When Na+ is replaced by Li+ or choline, the secretory Na+ concentration is decreased, although less than in the bathing medium, and the K+ concentration is increased. When Na+ is replaced by K+, the Na+ and the K+ concentration in the secreted fluid are approximately equal to their bathing medium concentrations. In the Li+ and choline medium, stimulation of the pancreas by carbachol or CCK-8 increases the fluid secretion rate. In addition, it increases the Li+ or choline concentration, and decreases the Na+ and K+ concentrations in the secreted fluid. In normal and K+ medium, stimulation causes only a slight increase in fluid secretion rate, with no change in the secretory Na+ concentration. In normal medium, stimulation leads to a decrease in the secretory K+ concentration. The effects of replacing Na+ appear to be the result of a direct inhibition of the active HCO3- transport underlying secretion, and an indirect inhibition related to the permeability of the pancreas for the various cations. The stimulants are likely to act by increasing the permeability of the tight junctions.     

A computer simulation of a neuron net model as a self-organizing system

A neural net model is simulated on an IBM-1130 digital computer. The model includes rules for learning of the presented patterns. The learning algorithm uses an iteration procedure, in order to compute the ultimate cross coupling-coefficients between the neurons for a specific pattern. The network has a set of latent cyclic modes or reverberations. If the net is stimulated briefly, by presenting a pattern, it will subsequently either return to quiescence or settle into periodic activity in one of its cyclic modes.     

The secretory activity of rat nasal glands and the effect of cholinergic drugs

Summary The secretory behaviour of rat nasal glands, under normal conditions and after the application of cholinergic drugs, has been studied using morphological and radiobiochemical techniques.Autoradiography and electrophoresis provide evidence for the selective incorporation of ³H-arginine into the glycoprotein containing fraction of the nasal glandular secretion. Radiobiochemical experiments show that labelled arginine is rapidly incorporated into the acinar cells of unstimulated glands, although it takes approximately 4 h before the labelled secretory proteins leave the cells. The secretion of proteins is stimulated by the parasympathetic agonist pilocarpine, whose main action is to promote discharge. Histological sections show a depletion of secretory granules after pilocarpine treatment. The cholinergic antagonist atropine inhibits the secretion; the acinar cells are completely filled with secretory granules following this treatment. The time course of the events following atropine administration suggests that there is no feed-back system controlling glycoprotein synthesis.The techniques employed here therefore appear to be useful for studying the effects of drugs that interfere with the secretory activity of the nasal glands.     

Effects of dibutyryl cyclic GMP on rabbit pancreas secretion

The isolated rabbit pancreas responds to the hormone cholecystokinin-pancreozymin and its C-terminal peptide with increases in protein secretion and in paracellular permeability. Dibutyryl cyclic GMP competitively inhibits these responses to the C-terminal octapeptide, but with different sensitivity. In low concentrations dibutyryl cyclic GMP lowers only the increase in the paracellular permeability, whereas in high concentrations it inhibits both the protein secretion and the permeability increase. The effect can be explained by assuming competition between dibutyryl cyclic GMP and the hormone at the level of the pancreozymin receptors.     

Expression of cytokeratin polypeptides during development of the rat inner ear

Summary The expression of cytokeratin polypeptides in the different epithelia of the developing inner ear of the rat from 12 days post conception to 20 days after birth was analysed immunohistochemically, using a panel of monoclonal antibodies. Throughout the development of the complex epithelial lining of the inner ear originating from the otocyst epithelium, only cytokeratins which are typical of simple epithelia were expressed. Cytokeratins 8, 18, and 19 were detectable shortly after the formation of the otocyst from the ectoderm (12 dpc), whereas cytokeratin 7 expression was delayed and first appeared in the vestibular portion and subsequently in the developing cochlear duct. During the development of the different types of specialized cells, differentiation-dependent modulation of the cytokeratin expression patterns was observed. In the mature inner ear, the specialized cell types displayed a function-related cytokeratin expression profile, both in the cochlear and vestibular portion. Cytokeratin expression in the flat epithelium of the vestibular portion suggests a more complex composition of this epithelium than has been established from routine morphology. Remarkably, the cochlear sensory cells were apparently devoid of cytokeratins, but no final conclusion could be drawn on the presence of cytokeratins in the sensory cells of the vestibular portion, because of the difficulty to delineate the cell borders between sensory cells and supporting cells.     

A Mu gin complementing function and an invertible DNA region in Escherichia coli K-12 are situated on the genetic element e14

The Gin product catalyzes an inversion of 3,000 base pairs of DNA in the genome of bacteriophage Mu. The orientation of the invertible of G-region determines the host range of the phage. Gin- mutants are complemented by a host function in strain HB101 and several other Escherichia coli K-12 strains. At least three clones in the E. coli gene bank described previously (L. Clarke and J. Carbon, Cell 9:91-99, 1976) contained the gin complementing function. This function, which we named pin, catalyzes an inversion of 1,800 base pairs in the adjacent DNA. The invertible region, named the P-region, together with pin, was further subcloned on pBR322. Conjugation and transduction experiments mapped the pin gene between the genes purB and fabD near position 25 on the E. coli chromosome. Also situated in this region is e14, a cryptic, UV- excisable , genetic element (A. Greener and C.W. Hill, J. Bacteriol . 144:312-321, 1980). We demonstrated that pin and the P-region are part of e 14. The e 14 element was cloned on pBR322 by genetic manipulation techniques in vivo. It has the properties of a defective prophage containing integration and excision functions and a SOS-sensitive repressor.