再生障碍性贫血患者血清一氧化氮与细胞因子水平分析

生物体内的一氧化氮 (NO)作为一种反应极强的效应分子 ,不仅参与免疫调控 ,而且也是造血祖细胞生长和分化不可缺少的调节因子 [1 ]。本文通过对再生障碍性贫血 (AA)患者血清 NO与白细胞介素 - 2 (IL- 2 )、肿瘤坏死子 (TNF)、血小板生成素 (TPO)、红细胞生成素 (EPO)、GM- CSF、5种细胞因子水平测定 ,分析其与外周血象及各细胞因子间的相互关系 ,并探讨 NO及 IL- 2等细胞因子在 AA发生发展过程中的作用。1　材料和方法1.1　材料1.1.1　标本来源　 AA患者 5 0例 ,以 2 0 0 2年 3月至 2 0 0 4年4月我院确诊为 AA的患者为研究对象…     

Handling of asymmetrical dimethylarginine and symmetrical dimethylarginine by the rat kidney under basal conditions and during endotoxaemia.

BACKGROUND: Asymmetrical dimethylarginine (ADMA) is capable of inhibiting nitric oxide synthase enzymes, whereas symmetrical dimethylarginine (SDMA) competes with arginine transport. The potential role of inflammation in the metabolism of ADMA has been elucidated in an in vitro model using tumour necrosis factor-alpha, resulting in a decreased activity of the ADMA-degrading enzyme dimethylarginine dimethylaminohydrolase (DDAH). The kidney probably plays a crucial role in the metabolism of ADMA by both urinary excretion and degradation by DDAH. We aimed to further elucidate the role of the kidney in a rat model under basal conditions and during endotoxaemia. METHODS: Twenty-five male Wistar rats weighing 275-300 g were used for this study. The combination of arteriovenous concentration differences and kidney blood flow allowed calculation of net organ fluxes. Blood flow was measured using radiolabelled microspheres according to the reference sample method. Concentrations of ADMA, SDMA and arginine were measured by high-performance liquid chromatography. RESULTS: The kidney showed net uptake of both ADMA and SDMA and fractional extraction rates were 35% and 31%, respectively. Endotoxaemia resulted in a lower systemic ADMA concentration (P = 0.01), which was not explained by an increased net renal uptake. Systemic SDMA concentrations increased during endotoxaemia (P = 0.007), which was accompanied by increased creatinine concentrations. CONCLUSIONS: The rat kidney plays a crucial role in the regulation of concentrations of dimethylarginines, as both ADMA and SDMA were eliminated from the systemic circulation in substantial amounts. Furthermore, evidence for the role of endotoxaemia in the metabolism of dimethylarginines was obtained as plasma levels of ADMA were significantly lower in endotoxaemic rats.     

Inhibition of nitric oxide synthase attenuates blood-brain barrier disruption during experimental meningitis

Increased permeability of the blood-brain (B-B) barrier is observed during meningitis. Preventing B-B barrier alterations is important because adverse neurological outcomes are correlated with breeches in barrier integrity. It was hypothesized that pathological production of nitric oxide (NO) contributes to B-B barrier disruption during meningitis in the rat. Experimental meningitis was induced by intracisternal (i.c.) administration of lipopolysaccharides (LPS) or vehicle. Groups of rats were concomitantly infused intravenously (i.v.) with saline or the NO synthase inhibitor, aminoguanidine (AG). Eight h after i.c. dosing, B-B barrier alterations were quantitated pharmacokinetically using [¹⁴C]sucrose. Serum and regional brain tissues were obtained 0–30 min after tracer dosing and sucrose influx transfer coefficients ( K_{in (app)}) were calculated from the brain tissue data. Compared to the control groups (i.c. vehicle/i.v. saline), the K_{in (app)} of the i.c. LPS/i.v. saline group increased 1.6–2.1-fold in various brain regions, thus confirming previous observations of increased [¹⁴C]sucrose barrier penetration during meningeal inflammation. Remarkably, i.v. administration of AG to i.c. LPS-treated rats significantly inhibited meningeal NO synthesis and decreased K_{in (app)} permeability alterations in the B-B barrier, compared to i.c. LPS/i.v. saline-treated rats. Regional brain K_{in (app)} estimates in the i.c. LPS/i.v. AG group were similar to control groups (i.c. vehicle/i.v. AG and i.c. vehicle/i.v. saline). In conclusion, these data suggest the general concept that excessive NO production during neuroinflammatory diseases contributes to disruption of the blood-brain barrier.     

Antigen-independent cross-talk between macrophages and CD8+ T cells facilitates their cooperation during target destruction

Inflammatory sites associated with tissue destruction often contain a complex mixture of cells including macrophages as well as CD8+ and CD4+ T cells. Here, we have investigated, using islets of Langerhans as targets, if CD8+ T cells and macrophages can cooperate in tissue destruction. CD8+ T cells obtained from the islet inflammatory lesion of non-obese diabetic mice or cloned islet-specific CD8+ T cells were ineffective in destroying islets on their own. Including increasing numbers of macrophages in co-cultures of islets and islet-derived or cloned CD8+ T cells progressively increased and accelerated islet destruction. Macrophages alone were ineffective. Macrophage-depleted islets were not destroyed by islet-derived CD8+ T cells. For cooperative islet destruction to occur, beta cells, but not macrophages, needed to be able to present antigens to CD8+ T cells. CD8+ T cells triggered NO production by macrophages, while macrophages triggered IFN-gamma production by CD8+ T cells. Each of these factors was partially effective, but not sufficient, for maximal islet destruction. Antibodies specific for ICAM-1 and LFA-1 inhibited both cooperative islet destruction and cross-stimulation of CD8+ T cells and macrophages. The data suggest that if CD8+ T cells become only weakly activated by target cells, they are not able to destroy target tissue on their own. However, such CD8+ T cells and local macrophages may still cross-stimulate each other, which then facilitates target destruction. For this to occur, target cells, but not macrophages, need to present antigen to CD8+ T cells.     

Inhibition of nitric oxide synthase reduces Sephadex-induced oedema formation in the rat lung: Dependence on intact adrenal function

In the present study we have investigated the effect of L-nitro arginine mono methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthase on Sephadex induced inflammation in the rat lung. Instillation of Sephadex into the airways induced an inflammatory reaction characterized by a long-lasting interstitial oedema, measured as an increase in lung weight, and an influx of inflammatory cells into the airways. L-NAME given s.c. prevented the increase in lung weight following Sephadex instillation. The inactive enantiomer D-NAME had no effect, nor did aminoguanidine which indicates that this effect of L-NAME was mediated by inhibition of the constitutive form of NOS. Treatment with L-NAME did not reduce an established oedema. In contrast, L-NAME tended to enhance the influx of oesinophils into the airways of Sephadex-instilled animals.L-NAME did not have any effect on the development of oedema in adrenalectomized rats or in animals where formation of glucocorticosteroids (GCS) was inhibited with metyrapone. L-NAME did not however, increase plasma levels of corticosterone. The present results indicate that, in this model, inhibition of NO-synthesis has marked anti-inflammatory effects. The underlying mechanism is complex but seems not to involve prevention of overproduction of NO.     

Inhalation anesthetic-induced neuroinvasion by an attenuated strain of West Nile virus in mice

There are contradictory reports regarding the effects of inhalation anesthetics on the immune system. Measurable immune responses have been studied in vitro, but little is known about the in vivo effects in the intact organism. We used an attenuated, non-neuroinvasive, nonlethal strain of the encephalitic West Nile virus, termed WN-25, which can become lethal in combination with environmental stressors, to study possible modulatory immune effects of inhalation anesthetics in mice. Both single short-term exposure and repeated exposure to halothane and nitrous oxide were studied. Exposure to 30% CO2 served as a positive control. Mortality, brain invasion, spleen weight, and antiviral antibodies served as the experimental endpoints. Halothane and nitrous oxide led to viral brain invasion, increased mortality, and suppressed immune response in a concentration- and time-dependent manner. Repeated exposures had a cumulative effect. Assessment of the stability of the viral attenuation did not demonstrate any alteration in the character of the virus, suggesting an increased access to the brain by inhalation anesthetics that led to the fatal encephalitis. These findings may be of special concern to populations at risk, such as operating room staff and patients undergoing general anesthesia in endemic areas of encephalitic virus species, in which subclinical infection may develop into an overt disease.     

Androgen receptor independent cardiovascular action of the antiandrogen flutamide

We have previously shown that flutamide (specific antagonist of the androgen receptor) has antihypertensive effects. In the present study we examined the mechanisms of flutamide action in the vasculature. The vascular effects of flutamide were assayed in aortae isolated from male or female Sprague-Dawley rats and from rats or mice lacking a functional androgen receptor ( tfm, testicular feminization mutation). The effect of flutamide on coronary flow was tested in isolated hearts. In addition, male hypertensive rats with tfm mutation were treated with flutamide, and blood pressure was monitored. Flutamide induced a relaxation of rat aortae from all the strains used (maximum relaxation at 10 microM: 51.3+/-5.2% of phenylephrine contraction) and increased the coronary flow. The aortic relaxation to flutamide was abolished by endothelium removal, or by inhibition of nitric oxide synthase, guanylyl cyclase, and tyrosine kinase but not by calmodulin inhibition. Flutamide treatment attenuated the development of hypertension in mouse renin transgenic rats with the tfm mutation. Flutamide produces direct vasodilation by inducing release of NO from the endothelium and causes subsequent activation of soluble guanylyl cyclase in an active androgen receptor independent manner. This response may contribute to the observed antihypertensive actions of flutamide.     

Morphine-6beta-glucuronide modulates the expression of inducible nitric oxide synthase

The immunomodulatory effects of morphine are well established; however, suprisingly little is known about the immunomodulatory properties of the major metabolites of morphine. The present study tests the hypothesis that expression of inducible nitric oxide synthase (iNOS) is modulated by the administration of the morphine metabolite, morphine-6-glucuronide. The initial study using rats shows that morphine-6-glucuronide administration (0, 1.0, 3.163, 10 mg/kg s.c.) results in a pronounced reduction in lipopolysaccharide (LPS)-induced expression of iNOS (inducible nitricoxide synthease) in spleen, lung, and liver tissue as measured by western blotting. Morphine-6-glucuronide also produces a reduction in the level of plasma nitrite/nitrate, the more stable end-product of nitric oxide degradation. In a subsequent study, administration of the opioid receptor antagonist, naltrexone (0.1 mg/kg) prior to the injection of morphine-6-glucuronide (10 mg/kg) blocks the morphine-6-glucuronide induced reduction of iNOS expression and plasma nitrite/nitrite levels indicating that the effect is mediated via the opioid-receptor. This study provides the first evidence that morphine-6-glucuronide alters the expression of iNOS.     

Effect of NO-generating compound NaNO<Subscript>2</Subscript> on ultrastructure of synaptic vesicles of glutamatergic synapses

Ultrastructure of synaptic vesicles in axon terminals of granule cells from isolated cerebellum of Rana temporaria frogs under the influence of NO-generating compound NaNO₂ in various concentrations and electrical stimulation was evaluated by the method of electron microscopy. NO-generating compound in low concentration induced translocation of synaptic vesicles and formation of small clusters. The size and structure of synaptic vesicles remained unchanged under these conditions. Increasing the concentration of NaNO₂ led to swelling of synaptic vesicles, formation of arranged heaps from individual vesicles or fusion of their content. Electrical stimulation of the cerebellum in the presence of NaNO₂ increased damage to synaptic vesicles. These experimental data model some stages observed in stroke. The formation of clusters from synaptic vesicles is a compensatory and adaptive response maintaining the structure of synaptic vesicles and protecting neurons from high concentrations of glutamate. Glutamate produces a toxic effect on nerve cells and glial cells of the cerebellum under pathological conditions, which is accompanied by impairment of signal transduction from presynaptic to postsynaptic neurons. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 146, No. 7, pp. 13–17, July, 2008     

Effect of Insulin on NO Production by Monocytes from Patients with Metabolic Cardiovascular Syndrome

Parameters of NO metabolism in the gingiva were studied during experimental periodontitis accompanied by alloxan diabetes and exogenous hypercholesterolemia. We measured activities of inducible and constitutive NO synthase and concentrations of stable NO end metabolites in rat gingival tissue (total contents of nitrite and nitrate). Under pathological conditions NO metabolism significantly differed from the control. Treatment with mexidol for 14 days significantly decreased activity of inducible NO synthase in the gingiva of experimental animals. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 10, pp. 384–386, October, 2005