Epstein-Barr病毒特异性T细胞对重组痘苗病毒表达LMP和EBNA2的靶细胞的识别

本文用EB病毒转化自体淋巴细胞所建立的类淋巴母细胞系(LCL),以及用EB病毒潜伏感染膜蛋白(LMP)基因和核蛋白-2(EBNA2)基因与痘苗病毒重组的重组病毒(Vac-LMP和Vac-EBNA2)感染的自身纤维母细胞,同时作为刺激细胞和靶细胞,以~(51)Cr释放法检测5例血清中EB病毒VCA—IgA抗体阳性者及1例阴性健康者外周血单个核细胞(PBMC)的特异性T细胞杀伤效应。结果表明,用自身LCL激活的EB病毒特异性T细胞杀伤效应高峰出现在第14～28天;参与杀伤性细胞免疫反应的T细胞亚群主要是T3、T8阳性的细胞毒性T细胞,其对靶细胞的识别及杀伤受HLA-I的限制。用重组牛痘病毒感染的纤维母细胞作靶细胞或刺激细胞,有1例供者可接受LMP,另1例可接受EBNA2的刺激,并对相应的靶细胞产生特异性T细胞杀伤反应,表明EB病毒-LMP和EBNA2可能既是EB病毒特异性T细胞的刺激抗原,又是其识别的靶抗原。     

Influence of age and splanchnic nerve on glucagon-induced changes of adrenomedullary catecholamine content and blood glucose level in the avian group

Summary Glucagon (0.1 mg · 100 g body wt^-1) increased norepinephrine (NE) content in adult pigeon (31%) and parakeet (58%), decreased NE content in the adrenal medulla of newly-hatched pigeon (36%), parakeet (52%), and crow (44%) 0.5 h after treatment. Epinephrine (E) content decreased to 26% and 59% of control values, respectively, in newly-hatched pigeon and parakeet 0.5 h after treatment. Glucagon produced hyperglycemia irrespective of age and species. The results indicate that aging modulates glucagon-induced changes of catecholamine (CA) content. In the innervated (I) adrenal gland of pigeon, glucagon caused a 31% increase of NE content 0.5 h after injection, a 46% decrease of NE content 12 h after injection, and a 192% increase of NE 24 h after injection. In the I gland of pigeons, glucagon also caused a 61% decrease of E content 4 h after injection, and brought about a 100% increase of E 24 h after injection. Glucagon-induced changes of CA content differ significantly between the I and denervated (D) glands. The results indicate that the splanchnic nerve regulates release and/or resynthesis of CA induced by glucagon.Abbreviations ANOVA analysis of variance - CA catecholamine - D denervated - E epinephrine - I innervated - MS mean sum of squares - NE norepinephrine - PNMT phenylethanolamine-N-methyl transferase - SS sum of squares - SV source of variation - TH tyrosine hydroxylase     

Role of splanchnic nerve on steroid-hormone-induced alteration of adrenomedullary catecholamines in untreated and reserpinized pigeon

Summary The aim of the present investigation was to ascertain (1) the effect of steroid hormones (corticosterone, dexamethasone, deoxycorticosterone, progesterone, testosterone and oestrogen) on the neural regulation of adrenomedullary catecholamine (CA) content, and (2) the neural modulation of the effect of glucocorticoid hormones (corticosterone and dexamethasone) on reserpine-induced resynthesis of CA. The experiment was conducted on unilaterally splanchnic-denervated pigeons. The findings revealed that 7 consecutive days of steroid treatments (2.5 mg·kg b.w.^-1, i.m.) resulted in significant changes of CA content. Interestingly, the changes of epinephrine (E) content differed significantly between the innervated and denervated glands. This clearly indicates that the splanchnic nerve regulates steroid-induced alterations of E content in the pigeon. The results further revealed that the glucocorticoid hormones augmented reserpine-induced resynthesis of CA specifically in the innervated glands. This confirms that the splanchnic nerve is essential for the synergistic action of glucocorticoids and reserpine in accelerating resynthesis of CA.Abbreviations ANOVA analysis of variance - b.w. body weight - CA catecholamine - DBH dopamine--hydroxylase - df degrees of freedom - E epinephrine - i.m. intramuscular - i.p. intraperitoneal - mRNA messenger ribonucleic acid - NE norepinephrine - PNMT phenylethanolamine-N-methyl transferase - TH tyrosine hydroxylase     

The role of ATP and free ADP in metabolic coupling during fuel-stimulated insulin release from islet beta-cells in the isolated perfused rat pancreas.

The isolated perfused rat pancreas was used to test the hypothesis that total cellular ATP or the ratio of ATP/free ADP plays the primary role in coupling intermediary metabolism to the biophysical events that are the basis of glucose-stimulated insulin release. The pancreas was preperfused for 20 min with 4.0 mM of a physiological mixture of 20 amino acids plus 4.2 mM glucose, and insulin release was then stimulated for 150 s by suddenly increasing the glucose to 8.3 mM. The pancreas was sampled at 24, 48, 72, and 150 s after the switch. The content of total ATP, ADP, AMP, Pi, phosphocreatine, and creatine were measured in beta-cell enriched cores of pancreatic islets microdissected from freeze-dried pancreas cryostat sections. Metabolites were measured by quantitative histochemical enzymatic cycling techniques. Modeling studies were carried out to assess the impact of biochemical analytical results on the membrane potential of the beta-cells. The level of free ADP was calculated using the creatine kinase equilibrium reaction and an intracellular pH of 7.2. First phase insulin release was stimulated at least 10-fold with the maximum reached 45 s after adding high glucose. The biochemical analytical data demonstrate that the total cellular level of the putative coupling factor ATP and of the ratios ATP/free ADP and ATP/free ADP x Pi are not significantly influenced by a glucose level change that causes a more than 10-fold surge of insulin release. The strength and limitations of the present experimental strategy and the implications of the results for our understanding of metabolic coupling in glucose-stimulated insulin release are discussed.     

Serovars of multi-antibiotic resistant Escherichia coli from the freshwater environs of Calcutta, India

For a period of one year (March 1987 to February 1988), the incidence of Escherichia coli was determined in water, sediment and plankton collected from two sampling sites in a freshwater lake extensively used by humans and animals. Densities of E. coli associated with plankton was the lowest while sediments, especially at site 2, harbored high densities of the organism. Correlation coefficients revealed that the density of E. coli in water samples was linearly correlated to temperature, pH of water, sediment and humidity. Stepwise multiple regression analysis, however, showed that sediment temperature was the dominant variable which could explain 27% of the observed variation in the numbers of E. coli in the overlying waters (p = less than 0.001). Of the 150 environmental E. coli strains which were characterized, 31 (20.7%) were found to belong to the classic enteropathogenic E. coli (EPEC) serogroups. Seven of the serogroups among the environmental EPEC strains were also encountered from EPEC strains isolated from human cases during a concurrent clinical study. None of the 150 environmental strains were enterotoxigenic or enteroinvasive but 4 strains possessed HEp-2 cell adhesive factor. With the exception of one, all the EPEC strains isolated were multi-drug resistant. From this study, it was evident that the lake is an important source of infection of EPEC and other related diarrheagenic E. coli.     

Genetic and biochemical analysis of mutation(s) affecting ricin internalization in Chinese hamster ovary cells

We have previously reported the isolation and characterization of Chinese hamster ovary (CHO) cell mutants defective in the internalization of ricin (Ray, B., and Wu, H.C. (1982) Mol. Cell. Biol. 2, 535-544). These mutants also do not exhibit the enhancement of ricin internalization by nigericin pretreatment at a low concentration, which is observed in the wild-type CHO cells. An analysis of somatic cell hybrids between the mutant and the toxin-sensitive wild-type CHO cell line shows that all of the phenotypes associated with the toxin resistance mutation are dominant in the hybrid cell lines. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of [3H]palmitic acid-labeled cell extracts from the mutant and toxin-resistant hybrid cell lines has revealed an increased incorporation of [3H] palmitic acid into two proteins with apparent molecular weights near 30,000 in the mutant and hybrid cells as compared to that in the wild-type cell line. Our studies indicate that these two fatty acyl proteins might be related to a dominant mutation(s) which results in a decreased uptake of ricin.     

Ligational behavior of a novel biologically active donor toward Cu(II) and Ni(II) ions and potentiation of its antibacterial activity by chelation with metal ions

The chelating behavior of a new multidentate ligand with tuberculostatic activity toward Cu(II) and Ni(II) ions has been studied. This ligand 3-(2-carboxyhydrazine)phenylimino-2-oximobutane(H2C POB) is found to chelate the above metal ions in both its keto and enol forms. The probable structures of all the complexes and the location of the bonding sites have been established through magnetic and spectroscopic (infrared, electronic) studies. The Cu(II) complex of the enol form exhibits subnormal magnetic moment at room temperature, indicating the probable existence of some sort of super exchange phenomenon in the system. The ligand itself and a few of its Cu(II) complexes have been found to exert powerful in vitro antibacterial activity toward some tuberculosis mycobacteria, such as Mycobacterium flae, Mycobacterium smegmatis, and Mycobacterium H37Rv.     

Induction of high-density-lipoprotein receptors in rat corpus luteum by human choriogonadotropin. Evidence of protein synthesis de novo.

The present studies investigated the specific binding of 125I-labelled high-density lipoprotein (125I-HDL) to plasma membranes. Golgi, rough endoplasmic reticulum and mitochondria/lysosomes, prepared from ovaries of rats injected with human choriogonadotropin (hCG) or 0.9% NaCl. Treatment in vivo with hCG resulted in 2-3-fold induction of 125I-HDL binding activity in all the subcellular organelles. The specific binding of HDL to various subcellular organelles was dependent on the amount of protein, lipoprotein concentration and incubation time. Equilibrium-binding studies revealed comparable Kd values (13-22 micrograms of HDL protein/ml) for HDL binding in all the subcellular organelles tested. Treatment with cycloheximide (2.0 mg/kg body wt.) before hCG administration abolished the induction of HDL receptors, suggesting the involvement of a protein-synthesis-dependent process in receptor induction. Analysis of equilibrium dissociation constants (Kd) for 125I-HDL binding in membranes from hCG-, cycloheximide-and saline-treated animals suggests that the increase in binding was due to an increase in the number of binding sites rather than a change in the affinity. Additionally, pretreatment with tunicamycin, an inhibitor of N-linked glycosylation, had no effect on hCG-mediated receptor induction, suggesting that glycosylation of the receptor may not be necessary for the interaction of HDL with its receptors.     

Phosphorylation of liver plasma membrane-bound calmodulin

In highly purified rat liver plasma membrane preparations, membrane-bound calmodulin was phosphorylated by a membrane-bound protein kinase using [gamma-32P]ATP as phosphate donor. Maximum phosphorylation of calmodulin occurred in the absence of calcium ion, but was significantly decreased in its presence. Plasma membrane-bound calmodulin was identified by the following criteria: (i) extraction from the membrane by EGTA, (ii) stimulation of the activity of the Ca2+-calmodulin-dependent enzyme, (3':5'AMP)-phosphodiesterase, by the EGTA extract, and (iii) electrophoretic comigration of EGTA-extracted protein with standard bovine brain calmodulin, both in the presence and the absence of Ca2+. Phosphorylation of the plasma membrane-bound calmodulin was shown by electrophoretic comigration of the 32P-labelled molecule with bovine brain calmodulin, the absence of phosphorylation of this protein band in calmodulin-depleted membranes, and a Western blot of the phosphorylated band using a calmodulin antibody. Treatment of plasma membrane preparations with sheep anticalmodulin serum prevented the phosphorylation of the calmodulin band. Phosphocalmodulin, which could be partially extracted from the membrane by EGTA, comigrated with bovine brain calmodulin in polyacrylamide gel electrophoresis.     

Influence of age and splanchnic nerve on the action of melatonin in the adrenomedullary catecholamine content and blood glucose level in the avian group

Summary A single intraperitoneal (IP) melatonin injection (0.5 mg/100 g body wt.) caused an increase in norepinephrine (NE) fluorescence and elevation of NE content in newly-hatched pigeons (Columba livia), but a reduction of NE fluorescence and depletion of NE content in the adrenal medulla of newly-hatched crows (Corvus splendens) after 0.5 h of treatment. In contrast, in adults melatonin caused increase in NE fluorescence and elevation of NE content only in the parakeet (Psittacula krameri).Half an hour of IP melatonin treatment (0.5 mg/100 g body wt.) induced release of epinephrine (E) from the adrenal medulla of newly-hatched pigeon and parakeet. In contrast, in the adults melatonin caused more than a two-fold increase in E in the pigeon, and a significant increase in the crow.Single IP melatonin injection (0.5 mg/100 g body wt.) caused hypoglycemia in the newly-hatched parakeet and adult pigeon, and hyperglycemia in newly-hatched pigeon after 0.5 h of treatment. Melatonin failed to regulate glucose homoeostasis in newly-hatched and adult crow.Splanchnic denervation of the left adrenal gland was performed in the adult pigeon. The right adrenal served as the innervated gland. Melatonin-induced modulation of catecholamines following a single IP injection (0.5 mg/100 g body wt.) revealed significant increases in NE fluorescence and NE content at 4 and 12 h after treatment in the denervated gland only, which gradually approached normal levels 9 days after treatment. In contrast, E content showed more than a two-fold increase over the control value in both the innervated and denervated glands 0.5 and 24 h after treatment. At 9 days after treatment, E content showed significant depletion in the innervated gland.The results of this study indicate that melatonin modulates catechol hormone content in avian adrenal medulla, and also regulates glucose homoeostasis (except in the crow). The splanchnic nerve plays a vital role in the synthesis of NE but has no effect on E.