Effects of aminoguanidine on nitric oxide production induced by inflammatory cytokines and endotoxin in cultured rat hepatocytes

AIM To study the effects of aminoguanidine(AG) and two L-arginine analogues Nω-nitro-L-arginine methyl ester (L-NAME) and Nω-nitro-L-arginine (L-NNA) on nitric oxide (NO) productioninduced by cytokines (TNF-α, IL-11β, and IFN-γ)and bacterial lipopolysaccharide (LPS) mixture(CM) in the cultured rat hepatocytes, andexamine their mechanisms action.METHODS Rat hepatocytes were incubatedwith AG, L-NAME, L-NNA, Actinomycin D (ActD)and dexamethasene in a medium containing CM(LPS plus TNF-α, IL-1β, and IFN-γ) for 24 h. NOproduction in the cultured supernatant wasmeasured with the Griese reaction. IntracellularcGMP level was detected with radioimmunoasey.RESULTS NO production was markedlyblocked by AG and L-NAME in a dose-dependentmanner under inflammatory stimuli conditiontriggered by CM in vitro. The rate of themaximum inhibitory effects of L-NAME (38.9%)was less potent than that obtained with AG(53.7%, P<0.05). There was no significantdifference between the inhibitory effects of AGand two L-arginine analogues on intracellularcGMP accumulation in rat cultured hepatocytes.Non-specific NOS expression inhibitordexamethasone ( DEX ) and iNOS mRNAtranscriptional inhibitor ActD also significantlyinhibited CM-induced NO production. AG(0.1mmol.L-1) and ActD (0.2ng@Lt) wereequipotent in decreasing NO production inducedby inflammatory stimuli in vitro, and botheffects were more potent than that induced bynon-selectivity NOS activity inhibitor L-NAME(0. 1 mmol@ L- 1) under similar stimuli conditions(P＜O.O1).CONCLUSION AG is a potent selectiveinhibitor of inducible isoform of NOS, and themechanism of action may be not onlycompetitive inhibition in the substrate level, butalso the gene expression level in rathepatocytes .

Current gene therapy for stomach carcinoma

Gastric cancer is common in China [1-42],and its early diagnosis and treatment in advanced stage are difficult [31-50].In recent years ,gene study in cancer is a hotspot ,and great progress has been achieved [41-80] .Cancer gene therapy has shifted from the imagination into the laboratory and clinical trials.

The effects of androgen on penile reflex, erectile response to electrical stimulation and penile NOS activity in the rat

Aim: To investigate the effects of androgen on penile erection through the reflex arc and penile corpus cavernosum,and study the respective roles of testosterone (T) and dihydrotestosterone (DHT) in penile erection in rats. Methods:Male Sprague-Dawley rats were castrated and implanted with silastic brand silicone tube containing T or DHT, with orwithout daily injections of a 5α-reductase inhibitor, MK-434. The penile reflex, erectile response to electrical stimula-tion (ES) of the cavernous nerves and penile nitric-oxide synthase (NOS) activity were observed under varying andro-genic status. Results: Penile reflex erection in the rat was, on the whole, related to serum T levels though the numberof glans engorgements was not. The number of cups and flips was significantly decreased by castration, and restoredto the control level by T supplementation. Erectile response to ES and NOS activity in penile tissue was also related toserum T level. T administered together with a 5α-reductase inhibitor no longer restored the number of reflex erection,erectile responses to ES and NOS activity in the corpus cavernosum. Conclusion: Androgen influenced the penile re-flex arc, corpus cavernosum, and the perineal striated muscles. In reflex erection, erectile response to ES and penileNOS activity in the rat, T seems to be first converted to DHT, the more active androgen modality. (Asian J Androl1999 Dec; 1: 169-174)

Puerarin decreases hypoxia inducible factor-1 alpha in the hippocampus of vascular dementia rats

In this study, a rat vascular dementia model was established by permanent bilateral common carotid arterial occlusion. Rats were intraperitoneally injected with puerarin 3 days before modeling, for 45 successive days. Results demonstrated that in treated animals hippocampal structures were clear, nerve cells arranged neatly, and cytoplasm was rich in Nissl bodies. The number of cells positive for hypoxia inducible factor-1 alpha, erythropoietin and endothelial nitric oxide synthase was reduced; and the learning and memory abilities of rats were significantly improved. Our experimental findings indicate that puerarin can significantly improve learning and memory in a vascular dementia model, and that the underlying mechanism may be associated with the regulation of the expression of hypoxia inducible factor-1 alpha.

Effect of stellate block on vasomotor factor, vascular endothelial nitricoxide synthase and pulmonary arterial pressure in rabbits with hypoxic pulmonary artery hypertension

BACKGROUND： At present, inhalation of nitrogen monoxidum （NO） or other angiotenic is widely used to cure hypoxic pulmonary artery hypertension. In addition, recent researches demonstrate that postganglionic fiber of stellate ganglion can regulate contents of blood vessel endothelium-calcitonin gene-related peptide （BVE-CGRP） and nitricoxide synthase （NOS） in lung tissue. Therefore, stellate ganglion which is blocked with the local anesthetic may cause therapeutic effects on hypoxic pulmonary artery hypertension. OBJECTIVE： To observe the effects of stellate block on calcitonin gene-related peptide （CGRP） of vasodilation factors, prostacyclin, endothelin-i of vasoconstriction factors, thromboxan, blood vessel endothelium-nitricoxide synthase （BVE-NOS） and mean arterial pressure of lung tissue in rabbits with hypoxic pulmonary artery hypertension. DESIGN： Randomly controlled animal study. SETTING： Neurological Institute of Taihe Hospital Affiliated to Yunyang Medical College. MATERIALS： A total of 24 adult Japanese rabbits of both genders and weighing 2.3 - 2.6 kg were provided by Animal Experimental Center of Hubei Academy of Medical Science. SP kit was provided by Beijing Zhongshan Biotechnology Co., Ltd.; moreover, kits of endothelin-1, CGRP, prostacyclin and thromboxan were provided by Radioimmunity Institute, Scientific and Technological Developing Center, General Hospital of Chinese PLA, and color image analytical system （Leica-Q500IW） was made in Germany. METHODS：The experiment was carried out in the Neurological Institute of Taihe Hospital affiliated to Yunyang Medical College from February to December 2002. ① Rabbits were performed with aseptic manipulation to exposure left stellate ganglion and then it was put in epidural catheter for 1 week. In addition, one end of epidural catheter was fixed near by stellate ganglion and the other end was fixed through dorsal neck. All rabbits were randomly divided into 4 groups, including normal control group, stellate block group, hypoxia group and hypoxia ＋ stellate block group, with 6 in each group. Rabbits in the normal control group were perfused with saline through epidural catheter with 0.5 mL once for three times per day and 3 successive days in total; in addition, rabbits in the stellate block group were perfused with 2.5 g/L bupivacaine through epidural catheter with 0.5 mL once for three times per day and 3 successive days in total. Rabbits in the hypoxia group were used to establish hypoxic pulmonary artery hypertension models. That was to say, the experimental rabbits were put in hypoxic box （containing sodalime and calcium chloride to absorb CO2 and water） and given various flows of oxygen and nitrogen through the two lateral wells simultaneously. And then, oxygen was monitored with oxygen-concentration monitoring device to control the concentration in （10±2）% for 8 hours per day and 2 successive weeks in total. Rabbits in the hypoxia ＋ stellate block group were used to establish hypoxia models as the same as those in the hypoxia group. Two weeks later, 2.5 g,/L bupivacaine was pushed into epidural catheter with 0.5 mL once for three times per day and 3 successive days in total. Breast was directly opened to measure mean pulmonary artery pressure.② 6 mL blood was collected through pulmonary arterial duct to measure levels of plasma CGRP, prostacyclin, endothelin-I and thromboxane with radio-immunity technique; meanwhile, immunohistochemical staining was used to observe the changes of BVE-NOS content of the experimental rabbits in all groups. MAIN OUTCOME MEASURES： Changes of CGRP, prostacyclin, endothelin-1 and thromboxane and BVE-NOS. RESULTS： A total of 24 experimental rabbits were involved in the final analysis. ①As compared with those in the normal control group, hypoxic pulmonary artery hypertension of the experimental rabbits was higher in the hypoxia group and hypoxia ＋ stellate block group after hypoxia [（3.8±0.30）, （3.16±0.45）, （2.60± 0.27） kPa, P 〈 0.05, 0.01]; CGRP was lower [（68.20 ±8.78）, （108.24 ±14.35）, （130.25 ±22.70） ng/L, P 〈 0.05, 0.01]; prostacyclin was lower [（94.45± 10.68）, （98.77± 12.31）, （155.27±20.67） ng/L, P 〈 0.01]; endothelin-1 was higher [（184.7±29.66）, （115.27± 13.62）, （98.20±11.52）, ng/L, P 〈 0.05, 0.01]; thromboxan was higher [（226.27 ±30.46）, （207.67 ±27.32）, （124.25 ± 16.89） ng/L, P 〈 0.01 ]. As compared with that in hypoxia group, hypoxic pulmonary artery hypertension was decreased in hypoxia ＋ stellate block group （P 〈 0.05）, CGRP was increased （P 〈 0.01）, and endothelin-1 was decreased remarkably （P 〈 0.05）. ② Level of BVE-NOS of the experimental rabbits was higher in stellate block group, hypoxia group and hypoxia ＋ stellate block group than that in the normal control group [（0.25±0.06）, （0.27±0.07）, （0.46± 0.12）, （0.14±0.03）, P 〈 0.05], and NOS level was higher in the hypoxia ＋ stellate block group than that in hypoxia group （P 〈 0.05）. CONCLUSION： Mean arterial pressure is decreased in rabbits with hypoxic pulmonary artery hypertension after stellate block and level of endothelin-1 is also decreased; however, levels of CGRP and NOS are increased respectively.

Effect of aging on expression of nitric oxide synthase I and activity of nitric oxide synthase in rat penis

<abstract>Aim: To investigate the effect of aging on the expression of nitric oxide synthase I (NOS I) and the activity of NOS in rat penis. Methods: Sixty male rats from 3 age groups (adult, old and senescent) were investigated. The expression of NOS I protein and mRNA in rat penis were detected by Western blot and RT-PCR respectively and the NOS activity, with ultraviolet spectrophotometry. Results: In the old and senescent group, NOS I protein expression was significantly decreased as compared with the adult. NOS I mRNA expression was well correlated with the protein expression. NOS activity was not statistically different between the adult and old groups, but it was significantly reduced in the senescent compared with the adult group (P<0.01). Conclusion: The aging-induced decreases in NOS I expression and NOS activity may be one of the main mechanisms leading to erectile dysfunction in the senescent rats.

Regeneration of neuronal nitric oxide synthase (nNOS)-containing nerve fibers in rat corpus cavernosum

Aim: To investigate the effect of cavernous nerve injury on the nNOS-containing nerve fibers in rat corpus cavernosum.Methods: Thirty-three male SD rats were randomized into 3 groups: 5 rats underwent pelvic exploration without tran-section of cavernous nerve as the sham-operated controls, the unilateral injury group (14 rats) had the cavernous nerve cuton one side, and the bilateral injury group (14 rats) had the nerves cut on both sides. Corpora cavernosa were harvestedat the 3rd week and 6th month after surgery, nNOS-positive nerve fibers were examined with strepavidin peroxidase im-munohistochemistry techniques (SP method). Results: After bilateral ablation, the nNOS-positive nerve fibers weresignificantly decreased at both the 3rd week ( 17 ± 4) and the 6th month (16 ± 4). For the unilateral injury group, thenNOS-positive nerve fibers were similarly decreased on the side of the neurotomy at the 3rd week (18 ± 6), but by the 6thmonth, the number increased significantly (61±9) and approximated the level on the contralateral side (81 ± 13). Con-clusion: In rats after unilateral cavernous nerve ablation, nNOS-containing nerve fibers might regenerate 6 months afteroperation, but regeneration did not occur in animals with bilateral cavernous nerve injury. Results suggest that duringpelvic radical surgery, the cavernous nerve should be preserved at least on one side in order to accomplish adequate regen-eration. (Asian J Androl 1999 Sep ; 1: 135 - 138)

Interventional effect of magnesium sulfate on nitric oxide synthase activity after acute craniocerebral injury

BACKGROUND： Abnormal changes in magnesium ion are closely related to cerebral injury. At present, some evidence indicates that magnesium reagent can improve nerve function and prognosis of patients with cerebral injury. OBJECTIVE： To observe the effect of magnesium sulfate on changes in nitric oxide synthase （NOS） activity in brain tissue of rats with acute craniocerebral injury. DESIGN： Completely randomized grouping design and randomly controlled study. SETTING： Laboratory of Neurosurgery, the Third Hospital of Chinese PLA. MATERIALS： Fifty-four male SD rats of clean grade and weighing 220 - 250 g were randomly divided into normal control group （n =6）, cerebral injury group （n =24） and magnesium sulfate group （n =24）. Especially, rats in cerebral injury group and magnesium sulfate group were equally divided into four subgroups and observed at 0.5, 2, 6 and 24 hours after model establishment. A solution of 125 g/L of magnesium sulfate was provided by the Seventh Pharmaceutical Factory of Wuxi and the NOS assay kit by Nanjing Jiancheng Bioengineering Institute. METHODS： The experiment was carried out in the Institute of Neurosurgery, the Third Hospital of Chinese PLA from August 2000 to August 2002. ① Rats in the cerebral injury group and magnesium sulfate group were anesthetized to establish cerebral injury models based on modified Feeney technique; magnesium sulfate group were intraperitoneally injected 600 mg/kg magnesium sulfate （125 g/L）, but rats in the normal control group remained untreated. ② At 0.5, 2, 6 and 24 hours after cerebral injury, rats in cerebral injury group and magnesium sulfate group were decapitated and brains were dissected. Cerebral cortex of rats in cerebral injury group was selected for NOS assay; in addition, at 0.5 hour after cerebral injury, a portion of the parietal lobe was selected from the brains of rats in the normal control group. Brain samples were homogenized, the homogenated centrifuged and the supernatants were used to measure NOS activity with NOS kit. ③ Differences among the three groups were compared with t test. MAIN OUTCOME MEASURES： NOS activity in cerebral cortex of rats in each group. RESULTS： A total of 54 SD rats were involved in the final analysis. At 0.5 hour after cerebral injury, NOS activity in cerebral cortex was （42.45 ± 13.46） nmol/L in cerebral injury group and （41.17 ± 12.53） nmol/L in magnesium sulfate group, respectively, which was higher than that in normal control group [（39.45 ± 11.84） nmol/L, P 〈 0.05]. At 2 hours after cerebral injury, NOS activities were （66.48 ±21.43） and （63.24 ± 19.18） umol/L, respectively, while at 6 hours after cerebral injury, NOS activities were （62.45 ± 24.18） and （51.97 ±20.46） nmol/L, respectively, which were higher than those in normal control group （P 〈 0.0 1）. At 24 hours after cerebral injury, NOS activity returned to basal level. Moreover, NOS activity was significantly lower in the magnesium sulfate group than that in the cerebral injury group at 2 and 6 hours after cerebral injury （P 〈 0.05, 0.01）.CONCLUSION： NOS activity is increased in injured brain tissue of rats with craniocerebral injury, and treatment with magnesium sulfate provides some degrees of protection possibly through inhibition of NOS activity after cerebral injury.

Monte Carlo Study of CO-NO Catalytic Surface Reaction Including CO-CO Repulsion

The CO-NO reaction on a catalytic surface is studied by using Langmuir-Hinshclwood thermal mechanism with Monte Carlo computer simulation. In this model, a novel concept of CO CO repulsion is introduced, which has experimental evidence due to the formation of dipoles when these molecules are chemisorbed on the surface. The system is investigated by applying two approaches of NO dissociation. In the first ca.se, NO always decomposes into N and O before adsorption on the surface, In the second case, NO adsorbs on the surface molecularly and then dissociates into N and O if a vacancy is present in its adjacent neighbourhood. The steady state reactive window （i.e. the continuous production of CO2 and N2） is obtained only with the diffusion of N-atoms on the surface, which extends with CO-CO repulsion in the first, case. Itowever, in the second case, reactive window is obtained with CO-CO repulsion alone, The reactive window width in this case is reasonably large. The first-order phase transition is eliminated in both the cases with CO-CO repulsion.

Effects of extract of Ginkgo biloba with venlafaxine on brain injury in a rat model of depression

Background Recent studies have indicated that chronic stress may give rise to brain damage, which is related to the genesis of depression. The purpose of this study is to investigate the effects of extract of Ginkgo biloba (EGb) and venlafaxine on depression.Methods Rats were treated with chronic and comprehensive stress to create a depression model. Immunohistochemistry was used to detect the expression of brain-derived neurotrophic factor (BDNF) in the hippocampal CA3 neurons of rats treated with different drugs. Behavioral changes of these rats were also examined. Results The expression of BDNF in the hippocampal CA3 neurons of the depression model decreased with a reduction in exploring behavior and a significant increase in fecal production. The expression of neuron nitric-oxide synthase (nNOS) protein also increased in the rats compared to normal controls. The rats treated with EGb and venlafaxine showed an increase in expression of BDNF and exploring behavior compared to untreated rats, but a decrease in nNOS and fecal production.Conclusions Rats sustain damage to the brain after being subjected to chronic and comprehensive stress. Our research has indicated that combined EGb with venlafaxine enhances the protection of neurons and decreases damage to the brain, while relieving the side effects of synthetic antidepressants.