生长激素、肝细胞生长因子和烟酰胺对人胎胰岛细胞的增殖作用

目的研究生长激素(GH)，肝细胞生长因子(HGF)和烟酰胺(NIC)对体外培养的人胎胰岛细胞的增殖作用及其交互作用。方法采用La(2^7)正交设计法在体外培养的人胎胰岛细胞的各组中分别加入不同浓度及组合的GH，HGF和NIC，培养48h后，收集各孔细胞，DTZ染色，计数。结果GH，HGF和NIC均起主要作用，HGF和NIC的交互作用不可忽视，最佳的生长因子组合及适配浓度为GH(100ng／ml)HGF(25ng／ml)NIC(100mmol／L)。结论GH，HGF和NIC均能促进体外培养的胰岛细胞的增殖，且组合GH(100ng／ml)HGF(25ng／ml)NIC(100mmol／L)的作用最大。     

Functional role and histological demonstration of nitric-oxide-mediated inhibitory nerves in dog sphincter of Oddi

Abstract Nitric oxide (NO) plays an important physiological role in regulating gastrointestinal motility. Involvement of endogenous NO was evaluated in the response to non-adrenergic, non-cholinergic (NANC) nerve stimulation of the dog sphincter muscle of Oddi. Transmural electrical stimulation (TES), nicotine (10^?5M) and K⁺ (10 mM) produced only a relaxation in the sphincter muscle strips contracted with substance P, which was not potentiated by atropine. The TES-induced relaxation was abolished by tetrodotoxin (3 times 10^?7 M) and oxyhaemoglobin (1.6 times 10^?5 M), but not affected by atropine (10^?7 M), propranolol (10^?7 M), phentolamine (10^?7 M), indomethacin (10^?6 M), chole-cystokinin (CCK, 10^?8 M) and vasoactive intestinal polypeptide (VIP, 10^?8 M). The relaxation was also abolished by treatment with N^G-nitro-L-arginine (L-NA, 10^?5 M), an NO synthase inhibitor. Nicotine produced a transient relaxation, which was abolished by tetrodotoxin, hexamethonium (10^?5 M) and L-NA, but not affected by atropine and N^G-nitro-D-arginine (D-NA, 10^?5 M). The addition of K⁺ elicited a transient relaxation, which was abolished by tetrodotoxin and L-NA. The inhibitory effects of L-NA were antagonized by L-arginine (10^?3 M). The presence of neurons containing nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase was histochemically demonstrated in the sphincter of Oddi. These findings may indicate that TES, nicotine and K⁺ liberate NO from NANC inhibitory nerve which is involved in the relaxation of the dog sphincter of Oddi. The muscular tone does not seem to be regulated by cholinergic nerves under the experimental conditions used.     

烟酰胺对高糖介导胰岛细胞bax及bcl-2表达的影响

目的 探讨烟酰胺对高糖环境下胰岛细胞bax及bel-2蛋白表达的影响。方法 体外培养大鼠胰岛细胞，应用免疫组化方法检测培养液中葡萄糖终浓度为22．2mmol／L及加入烟酰胺后胰岛细胞bax及bcl-2蛋白表达。结果 培养液中葡萄糖终浓度为22．2mmol／L时，胰岛细胞bax表达阳性，bcl-2表达较对照组降低。加入烟酰胺后bax表达降低，bcl-2表达增强。结论 烟酰胺能够上调bcl-2表达，下调bax表达，在高糖介导的胰岛细胞损伤中起一定作用。     

Growth and differentiation of adult rat hepatocytes regulated by the interaction between parenchymal and non-parenchymal liver cells

We have devised a medium which supports the continuous growth of hepatocytes without losing their replicative potential and differentiation capacity for a longer period. The medium HCGM, contains four key substances in addition to foetal bovine serum. They are epidermal growth factor, nicotinamide, ascorbic acid 2-phosphate and dimethylsulphoxide. When a non-parenchymal cell fraction containing small hepatocytes and non-parenchymal cells was cultured in HCGM, small hepatocytes grew clonally and differentiated into cells expressing either mature hepatocyte marker proteins or biliary cell marker proteins. Thus, for the first time, we showed the presence of a small compartment of bipotent and highly replicative clonogenic hepatocytes in the rat adult liver. HCGM also supported the growth of stellate cells (Ito cells) which were in the original preparation, suggesting the important role of stellate cells for the successful cultivation of hepatocytes. Together, these results suggest that a microenvironment is produced as a result of cooperative interactions between hepatocytes and stellate cells: one which stimulates the growth and differentiation of clonogenic hepatocytes.     

Role of oxidative stress,angiogenesis and chemo-attractant cytokines in the pathogenesis of ischaemic protection induced by remote ischaemic conditioning: Study of a human model of ischaemia-reperfusion induced vascular injury

Aims

We explored the effect of remote ischaemic conditioning (RIC) on endothelial function and on circulating mediators.

Calretinin- and parvalbumin-immunoreactive neurons in the rat main olfactory bulb do not express NADPH-diaphorase activity

The presence of nitric oxide synthase (NOS) in neuronal elements expressing the calcium-binding proteins calretinin (CR) and parvalbumin (PV) was studied in the rat main olfactory bulb. CR and PV were detected by using immunocytochemistry and the nitric oxide (NO) -synthesizing cells were identified by means of the reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-diaphorase) direct histochemical method. The possible coexistence of NADPH-diaphorase and each calcium-binding protein marker was determined by sequential histochemical-immunohistochemical double-labeling of the same sections. Specific neuronal populations were positive for these three markers. A subpopulation of olfactory fibers and olfactory glomeruli were positive for either NADPH-diaphorase or CR. In the most superficial layers, groups of juxtaglomerular cells, superficial short-axon cells and Van Gehuchten cells demonstrated staining for all three markers. In the deep regions, abundant granule cells were NADPH-diaphorase- and CR-positive and a few were PV-immunoreactive. Scarce deep short-axon cells demonstrated either CR-, PV-, or NADPH-diaphorase staining. Among all these labeled elements, no neuron expressing CR or PV colocalized NADPH-diaphorase staining. The present data contribute to a more detailed classification of the chemically- and morphologically-defined neuronal types in the rodent olfactory bulb. The neurochemical differences support the existence of physiologically distinct groups within morphologically homogeneous populations. Each of these groups would be involved in different modulatory mechanisms of the olfactory information. In addition, the absence of CR and PV in neuronal groups displaying NADPH-diaphorase, which moreover are calmodulin-negative, indicate that the regulation of NOS activity in calmodulin-negative neurons of the rat olfactory bulb is not mediated by CR or PV.     

Nicotinamide does not influence cytokines or exhaled NO in human experimental endotoxaemia

This study examined the hypothesis that nicotinamide could attenuate endotoxin-induced inflammatory responses in humans as indicated by levels of cytokines and nitric oxide. Ten healthy male volunteers participated in a randomised, double-blind, cross-over design with regard to the effects of nicotinamide. The volunteers received orally 4 g nicotinamide or placebo at 14 h and at 2 h preceding the experiment (total dose of 8 g). Endotoxin (E. coli, 2 ng/kg), was administered intravenously. Blood samples and haemodynamic data were collected prior to and up to 6 h after the endotoxin infusion. Orally exhaled NO was measured hourly. Following endotoxin, body temperature increased from baseline 36.3 +/- 0.09 degrees C to a maximum of 38.0 +/- 0.1 degrees C for all (mean +/- SEM, P < 0.001) and heart rate increased from 59 +/- 1.9 to 87.0 +/- 2.6 beats/min after 3 h (mean +/- SEM, P < 0.001). Endotoxin challenge also markedly elevated the TNF-alpha, IL-6, IL-8 and IL-10 concentrations (P < 0.001 versus baseline for all) during the study period. Orally exhaled NO also increased (P < 0.01) compared to baseline. Nicotinamide treatment did not influence the patterns of cytokine and NO response to endotoxin. In conclusion, there was no effect on the inflammatory parameters by oral nicotinamide at a dose of 8 g, limiting the potential use of this agent for anti-inflammatory purpose in man.     

Protective effect of 3-aminobenzamide,an inhibitor of poly (ADP-ribose) synthetase,against streptozotocin-induced diabetes

Summary The addition of 3-aminobenzamide (a potent inhibitor of poly(ADP-ribose)synthetase) into the incubation medium, prevents streptozotocin-induced inhibition of glucose-stimulated insulin release from isolated islets [control 142±14U·islet^–1·h^–1; streptozotocin (0.5mg/ml) 31±8; 3-aminobenzamide (l.0 mg/ml) 96±11; streptozotocin plus 3-aminobenzamide 122±19]. In vivo, intraperitoneal 3-aminobenzamide 300 mg/kg body weight prevents the appearance of overt diabetes in streptozotocin-treated rats. These protective effects of 3-aminobenzamide are dose-dependent and are similar to those exerted by nicotinamide. Taking into account that poly ADP-ribosylation is involved in the repair of damaged DNA, the protection exerted by 3-aminobenzamide against the diabetogenic effect of streptozotocin strongly supports the view that this acute effect may be a major consequence of the activation of DNA repair mechanisms in islet cells.     

NADPH氧化酶家族在心血管疾病中作用的研究进展

烟酰胺腺嘌呤二核苷酸磷酸氧化酶是心血管系统中活性氧(reactive oxygen species,ROS)的主要来源,它包 括7种亚型并分别表达在不同的心血管细胞及其细胞器中,参与调节细胞增殖、迁移、分化、凋亡、衰老和炎症反应 等多种活动,其衍生的ROS参与高血压、动脉粥样硬化、糖尿病血管病变、心肌梗死后心室重构等多种心血管疾病 的病理过程。