脐血浆治疗大鼠实验性肝衰竭及其机制的研究

本文采用脐血浆治疗实验性肝衰竭大鼠模型,并与成人血浆的疗效进行了比较。结果表明,脐血浆降低大鼠死亡率、血谷丙转氨酶水平,总胆红素浓度及使甲胎蛋白水平升高均明显高于成人血浆的作用（Ｐ＜０．０５）．肝脏病理组织学也显示脐血浆具有减轻病理损害和较快修复坏死组织的作用。提示脐血浆中含有促进肝细胞再生的因子,具有显著提高实验性大鼠肝衰竭的存活率。     

A Quick Embedding Method for Light Microscopy and Image Analysis of Cotton Fibers

A quick embedding method using UV polymerization of methacrylate plastic has been devised for embedding fibers encased in a polyvinyl chloride tube. The resulting embedments are suitable for light microscopy and image analysis.     

Expression of Lewis histo-blood group glycolipids in the plasma of individuals of Le(a+b+) and partial secretor phenotypes

Red cell Lewis antigens are carried by glycosphingolipids passively absorbed from plasma. Plasma was collected from a spectrum of individuals with normal and unusual Lewis/secretor phenotypes in order to investigate the glycolipid basis for the unusual phenotypes. Samples were obtained from: a Le(a+b–) ABH nonsecretor who secreted Lewis substances; a Le(a+b–) partial secretor; Le(a+b+) partial secretors; Le(a+b+) secretors; and a full range of normal Lewis/secretor phenotypes as controls. The Le(a+b+) samples represented Polynesian, Asian and Réunion Island ethnic backgrounds. Nonacid glycolipids were prepared, separated by thin-layer chromatography, and then immunostained with potent monoclonal antibodies of known specificity. Despite different serological profiles of the Le(a+b–) and Le(a+b+) Polynesian samples, their plasma glycolipid expressions were very similar, with both Le^a and Le^b co-expressed. The copresence of Le^a and Le^b in Le(a+b+) samples is in marked contrast to Caucasians with normal Lewis phenotypes, who have predominantly either Le^a or Le^b. These results suggest that there is a range of the secretor transferases in different individuals, possibly due to different penetrance or to several weak variants. We also show that Lewis epitopes on longer and/or more complex core chains appear to be predominant in the Polynesian Le(a+b+) samples. The formation of these extended glycolipids is compatible with the concept that in the presence of reduced secretor fucosyltransferase activity, increased elongation of the precursor chain occurs, which supports the postulate that fucosylation of the precursor prevents or at least markedly reduces chain elongation.Abbreviations CBA chromatogram binding assay - TLC thin-layer chromatography     

The effect of ethanol on lateral and rotational mobility of plasma membrane vesicles isolated from cultured mar 18.5 hybridoma cells

Intramolecular excimer formation of 1,3-di(1-pyrenyl)propane (Py-3-Py) and fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to evaluate the effect of ethanol on the rate and range of the lateral mobility and the range of the rotational mobility of bulk bilayer structures of the plasma membrane vesicles (ATCC-PMV) isolated from cultured hybridoma cells (ATCC TIB 216). In a concentration-dependent manner, ethanol increased the excimer to monomer fluorescence intensity ratio (I/I) of Py-3-Py in the ATCC-PMV and decreased the anisotropy (r), limiting anisotropy (r) and order parameter (S) of DPH in the ATCC-PMV. This indicates that ethanol increased both the lateral and rotational mobility of the probes in the ATCC-PMV. Selective quenching of DPH by trinitrophenyl groups was utilized to examine the range of transbilayer asymmetric rotational diffusion of the ATCC-PMV. The anisotropy (r), limiting anisotropy (r ) and order parameter (S) of DPH in the inner monolayer were 0.024, 0.032, and 0.069, respectively, greater than calculated for the outer monolayer of the ATCC-PMV. Selective quenching of DPH by trinitrophenyl groups was also used to examine the transbilayer asymmetric effects of ethanol on the range of the rotational mobility of the ATCC-PMV. Ethanol had a greater increasing effect on the range of the rotational mobility of the outer monolayer as compared to the inner monolayer of the ATCC-PMV. It has been proven that ethanol exhibits a selective rather than nonselective fluidizing effect within the transbilayer domains of the ATCC-PMV.This paper was supported in part by a research grant from the Korea Science and Engineering Foundation (KOSEF 88-1013-01) and from the Korea Research Foundation (1991–1993).     

Hormone- and growth factor-stimulated NADH oxidase

An NADH oxidase activity of animal and plant plasma membrane is described that is stimulated by hormones and growth factors. In plasma membranes of cancer cells and tissues, the activity appears to be constitutively activated and no longer hormone responsive. With drugs that inhibit the activity, cells are unable to grow although growth inhibition may be more related to a failure of the cells to enlarge than to a direct inhibition of mitosis. The hormone-stimulated activity in plasma membranes of plants and the constitutively activated NADH oxidase in tumor cell plasma membranes is inhibited by thiol reagents whereas the basal activity is not. These findings point to a thiol involvement in the action of the activated form of the oxidase. NADH oxidase oxidation by Golgi apparatus of rat liver is inhibited by brefeldin A plus GDP. Brefeldin A is a macrolide antibiotic inhibitor of membrane trafficking. A model is presented where the NADH oxidase functions as a thiol-disulfide oxidoreductase activity involved in the formation and breakage of disulfide bonds. The thiol-disulfide interchange is postulated as being associated with physical membrane displacement as encountered in cell enlargement or in vesicle budding. The model, although speculative, does provide a basis for further experimentation to probe a potential function for this enzyme system which, under certain conditions, exhibits a hormone- and growth factor-stimulated oxidation of NADH.     

Elemental concentrations in Nigerians with affective disorders using proton-induced X-ray emission

The concentrations of a number of elements are determined in the plasma and erythrocytes of 21 Nigerians (11 females, 10 males) with symptomatic affective disorders (11 depressives, 10 manics) and in 40 normal controls using proton-induced X-ray emission (PIXE) analysis. The study shows that there is significant elevation of plasma K and Zn, as well as the erythrocyte S in the patients relative to the controls. The plasma and erythrocyte Cu, and the erythrocyte P, Ca, Fe, and Zn are significantly lower in the patients compared to the controls. However, the plasma levels of Ca, S, Fe, and Br are similar in both the patients and the controls. Similarly, the concentrations of K, Br, and Rb show no significant difference in the erythrocytes of patients and controls.     

Study of trace elements in blood of cancer patients by proton-induced X-ray emission (PIXE) analysis

Proton-induced X-ray emission (PIXE) analysis was employed to determine the concentrations of six elements in the plasma and erythrocytes of 18 cancer subjects (15 males and 3 females) with neoplastic disorders and in 70 controls (35 males and 35 females). It was found that the concentrations of Br, K, and Zn were significantly elevated in the erythrocytes of the cancer subjects compared to the controls, whereas the concentration of Fe was significantly depressed, but with no difference observed in the concentration of Ca. In the plasma, the concentrations of Br, Cu, Ca, and K were significantly elevated, whereas the concentrations of Fe and Zn were found to be significantly depressed compared to the controls.     

Dietary subacute zinc deficiency and potassium metabolism

In a controlled animal experiment the effects of dietary subacute Zn deficiency on growth, Zn concentration, and tissue 42-K distribution were studied. Growth retardation caused lower body weight because both skeletal and heart muscle showed a reduction in cell mass. Zn concentrations were reduced in most tissues, however, they remained unaltered in heart muscle. 42-K activity increased in skeletal muscle and pancreas. We hypothesize the latter reflects the organs rate of metabolism, inducing the exocrine pancreas to increase Zn absorption; in skeletal muscle it may induce also alterations in cell potentiation, causing restless behavior. As suggested by the calculated specific K activity (Bq/mol), the K uptake was highest in liver and bone, high in pancreas and skeletal muscle and low in heart muscle. The latter suggests K retention in heart muscle. Specific activity in plasma and jejunum remained unaltered: K status and absorption seem unaffected. Zn deficiency causes different 42-K activities in the various tissues, that respond by alterations in K metabolism without the induction of K deficiency.     

Using planar lipid-bilayers to study plant ion channels

Ion channels are found in most plant membranes. They catalyse the rapid passive uniport of particular ions with varying selectivity. Planar lipid-bilayer (PLB) techniques have been developed to study the electrical activities of single ion channels in well-defined lipid and aqueous environments. They greatly facilitate both the biophysical and biochemical characterisation of ion channels and complement both conventional impaling electrode and membrane-patch voltage-clamping (patch-clamping) electrophysiological techniques applied in vivo. Bilayers can be formed across the end of patch-clamp pipettes or across apertures in specifically designed chambers. Ion channels in native membranes and purified, genetically altered or synthetic ion channels, proteins and peptides can all be studied in PLBs. The main applications of PLBs are (1) to study ion channels in membranes inaccessible to patch-clamp electrodes, (2) to provide a functional assay system during channel-protein purification and (3) to investigate the relationship between the molecular structure of ion channels and their conductance properties. In the present article we describe the techniques available for reconstitution and analysis of ion channels in PLBs and discuss how the PLB technique has been, and may be, useful to the study of plant ion channels.     

The involvement of a vanadate-sensitive ATPase in plasma membranes of a salt tolerant cyanobacterium

Plasma membranes of the marine cyanobacterium Spirulina subsalsa were tested for ATPase activity, and for involvement in salt stress. Transition of cells from saline to hypersaline medium enhances the respiratory activity associated with extrusion of Na⁺ and Cl⁻, and persisting salt stress induces synthesis of respiratory enzymes in the plasma membranes. The membranes possess an ATPase, specific for ATP and Mg²⁺ and sensitive to orthovanadate and dicyclohexylcarbodiimide. Immunoblot analysis of plasma membrane polypeptides from Spirulina subsalsa with anti- Arabidopsis H⁺-ATPase serum identified a single polypeptide of 100 kDa, which cross-reacted with the antibodies. An unusual feature of this ATPase is a specific stimulation by Na⁺ ions. Prolonged adaptation of S. subsals cells to hypersaline conditions induced an increase in ATPase activity in subsequent plasma membrane preparations, as well as a higher content of the 100 kDa polypeptide. It is suggested that the ATPase investigated is an H⁺-pump, which is involved in extrusion of Na⁺ and in conferring resistance to salt stress.