Elimination of methicillin‑resistant Staphylococcus aureus biofilms on titanium implants via photothermally‑triggered nitric oxide and immunotherapy for enhanced osseointegration

Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to explore more effective approaches for the treatment of MRSA biofilm infections.Methods:Herein,an interfacial functionalization strategy is proposed by the integration of mesoporous polydopamine nanoparticles(PDA),nitric oxide(NO)release donor sodium nitroprusside(SNP)and osteogenic growth peptide(OGP)onto Ti implants,denoted as Ti-PDA@SNP-OGP.The physical and chemical properties of Ti-PDA@SNP-OGP were assessed by scanning electron microscopy,X-ray photoelectron spectroscope,water contact angle,photothermal property and NO release behavior.The synergistic antibacterial effect and elimination of the MRSA biofilms were evaluated by 2′,7′-dichlorofluorescein diacetate probe,1-N-phenylnaphthylamine assay,adenosine triphosphate intensity,O-nitrophenyl-β-D-galactopyranoside hydrolysis activity,bicinchoninic acid leakage.Fluorescence staining,assays for alkaline phosphatase activity,collagen secretion and extracellular matrix mineralization,quantitative real‑time reverse transcription‑polymerase chain reaction,and enzyme-linked immunosorbent assay(ELISA)were used to evaluate the inflammatory response and osteogenic ability in bone marrow stromal cells(MSCs),RAW264.7 cells and their co-culture system.Giemsa staining,ELISA,micro-CT,hematoxylin and eosin,Masson's trichrome and immunohistochemistry staining were used to evaluate the eradication of MRSA biofilms,inhibition of inflammatory response,and promotion of osseointegration of Ti-PDA@SNP-OGP in vivo.Results:Ti-PDA@SNP-OGP displayed a synergistic photothermal and NO-dependent antibacterial effect against MRSA following near-infrared light(NIR)irradiation,and effectively eliminated the formed MRSA biofilms by inducing reactive oxygen species(ROS)-mediated oxidative stress,destroying bacterial membrane integrity and causing leakage of intracellular components(P<0.01).In vitro experiments revealed that Ti-PDA@SNP-OGP not only facilitated osteogenic differentiation of MSCs,but also promoted the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2-phenotype(P<0.05 or P<0.01).The favorable osteo-immune microenvironment further facilitated osteogenesis of MSCs and the anti-inflammation of RAW264.7 cells via multiple paracrine signaling pathways(P<0.01).In vivo evaluation confirmed the aforementioned results and revealed that Ti-PDA@SNP-OGP induced ameliorative osseointegration in an MRSA-infected femoral defect implantation model(P<0.01).Conclusions:Ti-PDA@SNP-OGP is a promising multi-functional material for the high-efficient treatment of MRSA infections in implant replacement surgeries.

Mutual effects of nitric oxide and iron on the growth of marine algae

Experiments on the effects of nitric oxide （NO） and iron on the growth of marine microalgae Skeletonema costatum were conducted. The results are as follows： exogenous NO could increase the growth rate of marine algae and raise the biomass remarkably under iron-deficient conditions. But it was a complicated process that the phytoplankton growth was influenced by NO and iron, which was controlled by the NO concentration, the nutrition level of the culture medium and the iron concentration, etc. Meanwhile, the iron concentration in the medium also has a direct influence on the growth and NO release capacity of the algae. Therefore, the effects of NO and iron on the growth of marine phytoplankton were mutual.

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 .

Effects of Infrasound on Gastric Motility, Gastric Morphology and Expression of Nitric Oxide Synthase in Rat

Infrasound widely condition, productive exists in nature, our living and traffic environment. Gastrointestinal tract is relatively sensitive to infrasound. However, the effect of infrasound on gastrointestinal function is unclear. Therefore, the purpose of our study was to observe the effects of infrasound on gastric motiliW and gastric morphology and to assess the expression of nitric oxide synthase （NOS） in gastric antrum after exposure to infrasound of 8 Hz - 130 dB for 2 hours per day for 14 consecutive days. Gastric motility was assessed by gastric fluid-emptying rate. Gastric morphology was evaluated by HE. The expression of NOS was measured by tissue microarray technology. The results would contribute to understand the role of infrasound in gastroenterology, and help to explain the mechanism of infrasound on gastroenterology.

Joint Effects of Mexidol and Nitroglycerine on Nitric Oxide Formation in Animal Liver Tissues

This work is investigating Mexidol (2-ethyl-6-methyl-3-hydroxy pyridine succinate) effect on the formation of nitric oxide (NO) in animal liver tissues, which is a regulator of many physiological processes and plays an important role in the vascular relaxation, neurotransmission and immune system functioning. Analyses performed by EPR spectroscopy revealed Hem-NO complex signals from paramagnetic centers in arbitrary units;produced nitrogen oxide amount in liver tissues was determined by method of double integration signals from nitrosyl complexes.

Effects of melatonin on learning abilities, cholinergic fibers and nitric oxide synthase expression in rat cerebral cortex

BACKGROUND: Melatonin is a kind of hormones derived from pineal gland. Recent researches demonstrate that melatonin is characterized by anti-oxidation, anti-senility and destroying free radicals. While, effect and pathogenesis of pineal gland on learning ability should be further studied. OBJECTIVE: To investigate the effects of pinealectomy on learning abiliy, distribution of cholinesterase and expression of neuronal nitric oxide synthase (nNOS) in cerebral cortex of rats and probe into the effect of melatonin on learning ability, central cholinergic system and nNOS expression. DESIGN: Randomized grouping design and animal study. SETTING: Department of Neurology, the 187 Hospital of Chinese PLA. MATERIALS: A total of 12 male SD rats, of normal learning ability testing with Y-tape maze, of clean grade, weighing 190-210 g, aged 6 weeks, were selected in this study. METHODS: The experiment was carried out in the Department of Neurology, Zhujiang Hospital from July 1997 to June 2000. All SD rats were divided into experimental group (n =6, pinealectomy) and control group (n =6, sham operation). Seven days later, rats in both two groups were continuously fed for 33 days. ① Learning ability test: The learning ability of rats was tested by trisection Y-type maze and figured as attempting times. ② Expression of acetylcholinesterase (AchE) was detected by enzyme histochemistry and nNOS was measured by SABC method. ③ Quantitative analysis of AchE fibers: AchE fibers density in unit area (surface density) was surveyed with Leica Diaplan microscope and Leica Quantimet 500+ image analytic apparatus and quantitative parameter was set up for AchE fibers covering density (μm2) per 374 693.656 μm2, moreover, the AchE fibers density was measured in Ⅱ-Ⅳ layers of motor and somatosensory cortex (showing three layers per field of vision at one time), in radiative, lacunaria and molecular layers of CA1, CA2 and CA3 areas, and in lamina multiforms of dentate gyrus. Three tissue slices were picked up randomly in the same part of each rat, together six tissue slices for nNOS expression and four near view (× 400) were selected in the parts of right neocortex, medial septal nucleus-diagonal band nucleus (SM-DB), corpus striatus and hippocampus to count nNOS-positive cells. MAIN OUTCOME MEASURES: Learning ability; distribution and quantitative analysis of AchE fibers; expression of nNOS in various cerebral areas. RESULTS: The twelve rats were all involved in the final analysis. ① Learning ability test: The learning abilities before operation in the experimental group [(14.67±4.97) times] were consistent with those in the control group [(14.33±4.32) times, P > 0.05], the learning abilities in the experimental group at 40 days after pinealectomy [(28.67±2.42) times] were obviously more than those before pinealectomy and those in the control group after operation [(13.83±8.33) times, P < 0.01]. ② Results of AchE-positive fibers density in cerebral cortex of rats: The AChE-positive fibers densities in motor and somatosensory cortex, CA1, CA2 and CA3 areas of hippocampus and in lamina multiforms of dentate gyrus in the experimental group were obviously lower than those in the control group [experimental group: (15 244±1 339), (14 764±1 391), (12 991±970), (15 077±1 020), (19 546±1 489), (19 337±1 378) μm2; control group: (21 001±1 021), (17 930±2 225), (17 260±1 342), (18 911±1 048), (24 108±1 671), (22 917±1 909) μm2, P < 0.01]. ③ Expression of nNOS in various cerebral areas: nNOS-positive cells in cerebral cortex of rats of the experimental group were more, furthermore the ones in somatosensory cortex were slightly more in motor cortex and the number (5.90±0.68) was more than that in the control group (3.68±0.39,P < 0.05). The nNOS-positive cells in SM-DB (16.21±2.03) were markedly more than those in the control group (9.32±1.05,P < 0.01). The nNOS-positive cells in hippocampus (4.27±0.75) and in corpus striatus (9.35±2.58) were not different with those in the control group (3.94±0.53, 8.96±2.31, P > 0.05). CONCLUSION: Decrease of melatonin due to pinealectomy of rats can result in learning disorder, which may be related to trauma of cholinergic neuron in cerebral cortex which were caused by nitric oxide neurotoxicity arose from the overexpression of nNOS in cerebral neocortex and SM-DB.

The application of nitric oxide delivery in nanoparticle-based tumor targeting drug delivery and treatment

Nitric oxide(NO) shows great role in tumor biology. Recent years, more and more researches utilized NO donor in tumor targeting drug delivery and treatment. In this review, we summarized the NO donors by their endogenous and exogenous stimuli. Then the application of NO donors, which was the main aim of the review, was discussed in detailed according to their functions, including inducing tumor cell apoptosis, reversing tumor multidrug resistance, inhibiting tumor metastasis and improving drug delivery.

Effect of a nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester on invasion of human colorectal cancer cell line SL-174T

AIM: To investigate the effect and mechanism of action of the nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on invasion and metastasis of human colorectal cancer cell line SL-174T.METHODS: Human colorectal cancer cell line SL-174T was cultured and treated separately with four different dosages of L-NAME for 72 h. Nitric oxide (NO) production was measured with Griess reagent. The effect of L-NAME on invasion and migration of SL-174T cells were evaluated by using Transwell chambers attached with polycarbonate filters and reconstituted basement membrane (Matrigel).RT-PCR was performed to determine the mRNA levels of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor metalloproteinase-2 (TIMP-2).RESULTS: L-NAME could significantly inhibit NO production of SL-174T in a dose-dependent manner. After being treated for 72 h with 0.2, 0.4, 0.8, and 1.0 mmol/L LNAME, respectively, the ability of the L-NAME treated SL174T cells to invade the reconstituted basement membrane decreased significantly (t = 8.056, P＜0.05;t= 14.467, P＜0.01;t= 27.785, P＜0.01;and t= 29.405,P＜0.01, respectively) and the inhibition rates were 10.29%,19.62%, 34.08%, and 42.23%, respectively. Moreover,L-NAME could inhibit migration of SL-174T cells, and the inhibition rates were 20.76%, 24.95%, 39.43%, and 46.85% for L-NAME at 0.2, 0.4, 0.8, and 1.0 mmol/L,respectively (t = 15.116, P＜0.01). In addition, after treatment with L-NAME, expression of MMP-2 mRNA was significantly decreased (t = 71.238, P＜0.01) and that of TIMP-2 mRNA was markedly increased (t = -13.020,P＜O.01).CONCLUSION: L-NAME exerts anti-invasive and antimetastatic effects on SL-174T cell line via downregulating MMP-2 mRNA expression and upregulating TIMP-2 mRNA expression.

Effect of nitric oxide synthase inhibitor N^G-nitro-L-arginine on the content of amino acid in ischemic brain tissues of rats

BACKGROUND： Nitric oxide synthase （NOS） inhibrtors have been widely used to investigate the role of NO on cerebral ischemic injury, but the results are controversial. Moreover, it has been considered to aggravate the ischemic neuronal damage with the release of excessively excitatory amino acids （EAA） during cerebral ischemia. On the other hand, some inhibitory amino acid is suggested to be important for the neuronal protection against ischemic brain damage. Our study has recently showed that treatment with the NOS inhibitor NG-nitro-L-arginine （L-NA） reduced focal cerebral ischemic damage. The effect of L-NA on the contents of excitatory and inhibitory amino acid in the rat brain following cerebral ischemia is still unclear. OBJECTIVE： By evaluating the effect of NOS inhibitor, L-NA on the contents of aspartate, glutamate, glycine and γ-aminobutyric acid （GABA） in striatum, hippocampus and cortex in the rat brain following cerebral ischemia respectively, to investigate the beneficial effect of L-NA on cerebral ischemic injury and the possible mechanism. DESIGN： A randomized and controlled experiment SETTING ： Department of Pharmacology, Hebei Academy of Medical Sciences MATERIALS： A total of 42 male healthy SD rats （grade Ⅱ, weighting 250-300 g） were provided by the Experimental Animal Center of Hebei Province （Certification： 04036）. Aspartate, glutamate, glycine, GABA, L-NA and 2,3,5-triphenyltetrazolium chloride （TTC） were obtained from Sigma Chemicals Co, St Louis, MO, USA. HPLC-ultraviolet detector system consisted of Agilent 1100 HPLC. METHODS： The experiment was carried out in Department of Pharmrcology, Hebei Academy of Medical Sciences from June 2005 to June 2006. Rats were randomly divided into three groups： sham-operated group （n = 6）, ischemic group （n = 18）, L-NA group （n = 18）. The model of focal cerebral ischemia in rat was prepared with intraluminal line occlusion methods. In sham-operated rats, the external carotid artery was surgically prepared, but the filament was not inserted. Each group was further divided into 3 subgroups （n = 6 for each）： drugs were administrated at 2, 6 and 12 hours after the middle cerebral artery occlusion （MCAO） respectively. L-NA （20 mg/kg, ip） was administrated, twice a day, for 3 consecutive days. Same volume of normal saline was administrated in ischemic and sham operation groups. The changes of infarcted volume and the contents of amino acids were respectively assayed. Image analysis software was used for the measurement of the infarcted area. The results were expressed as a percentage of the infarcted volume of cerebral/volume of whole brain （IV%） in order to control for edema formation. The contents of aspartate, glutamate, glycine and GABA in striatum, hippocampus and cortex in the rat brain following cerebral ischemia were respectively measured by HPLC method. All data were analyzed with one-way ANOVA and Dunnett＇s test. MAIN OUTCOME MEASURES： （1） The volume of cerebral infarction; （2） The contents of aspartate, glutamate glycine and GABA in brain tissue after cerebral ischemia. RESULTS ： All 42 rats were involved in the final analysis. （1） Infarcted volume： Volume was 0 in sham-operated group. When L-NA was administrated at 2 and 6 hours after MCAO, the infarcted volume was （20.13±3.59）% and （23.12±5.84）% in L-NA group, which was not similar to that in ischemic group [（22.10±3.98）%, （25.38± 5.37）%, P〉 0.05]. However, the infarcted volume was markedly decreased compared with that of ischemic group when L-NA was administrated at 12 hours after MCAO [（26.11±3.55）% and （37.15±3.58）%, P 〈 0.01]. Changes of amino acid content： At 2 and 6 hours after ischemia, the contents of aspartate, glutamate, glycine and GABA in striatum, hippocampus and cortex in ischemic group were significantly increased compared with those in sham-operated group （ P〈 0.05-0.01）. However, contents in L-NA group were similar to those in ischemic group （P 〉 0.05）. At 12 hours after ischemia, the contents of aspartate [（0.21 ±0.06）, （0.36±0.05）, （0.29±0.12） mg/g] and glutamate [（0.55±0.06）, （0.78±0.10）, （0.52±0.10） mg/g] in striatum, hippocampus and cortex in L-NA group were significantly decreased compared with those in ischemic group [（0.49±0.17）, （0.63± 0.03）, （0.51±0.15） mg/g; （0.98±0.30）, （1.15±0.15）, （0.93±0.15） mg/g, P〈 0.05-0.01]. Glycine in hippocampus was （0.40±0.07） mg/g, which was higher than that in ischemic group [（0.21±0.07） mg/g, P 〈 0.05]. GABA in striatum, hippocampus and cortex was （0.93±0.10）, （0.62±0.12） and （0.81 ±0.10） mg/g, respectively, which was higher than that in ischemic group [（0.60±0.08）, （0.37±0.17）, （0.59±0.10） mg/g, P 〈 0.05-0.01]. CONCLUSION ： It may be concluded that L-NA have beneficial effect on ischemic cerebral injury in ischemic later stage in rats. The possible mechanism is that L-NA can decrease the contents of aspartate and glutamate, increase the contents of glycine and GABA.

EFFECT OF RADIX SALVIAE MILTIORRHIZAE ON THE GENE EXPRESSION OF NITRIC OXIDE SYNTHASE IN ISCHEMIC RAT BRAINS

The effect of Radix Salviae Miltiorrhizae (RSM) on the gene expression of nitric oxide synthase (NOS) in rat brains daring ischemia was studied with in situ hybridization and the results were analyzed with IBAS 2000 Image Analysis System. It was found that NOS gene expression of cerebral cortex and caudate-putamen was markedly increased in 24 hours in ischemia group (P【 0.01). In RSM-treated rats, although the NOS gene expression of ischemic side was also increased as compared with contralateral cortex and caudate-putamen, it was significantly lower in RSM-treated rats than those of the controls (P【 0.05, P【 0.01). The present study indicates that RSM can partly inhibit NOS gene ex pression of cerebral cortex and caudate-putamen during ischemia. This may be one of the protective mechanisms of RSM on cerebral ischemia.

Role of nitric oxide in hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (IRI) occurs upon restoration of hepatic blood flow after a period of ischemia. Decreased endogenous nitric oxide (NO) production resulting in capillary luminal narrowing is central in the pathogenesis of IRI. Exogenous NO has emerged as a potential therapy for IRI based on its role in decreasing oxidative stress,cytokine release,leukocyte endothelial-adhesion and hepatic apoptosis. This review will highlight the influence of endogenous NO on hepatic IRI,role of inhaled NO in ameliorating IRI,modes of delivery,donor drugs and potential side effects of exogenous NO.

Nitric oxide mediated Staphylococcus aureus pathogenesis and protective role of nanoconjugated vancomycin

Objective:To investigate the relation between fruit seeds,plants residuals and appendicitis. Methods:Among cases that underwent appendectomy,the appendicitis cases having fruit seeds and undigested plant residuals in their etiology were examined retrospectively.Also, histopathological features,age,sex,and parameters of morbidity and mortality were used. Results:Fruit seed was found in one case(0.05%) with presence of pus in appendix lumen, undigested plant residuals in 7 cases(0.35%).It was determined that there were appendix inflammation in 2 of the plant residuals cases,while there were obstruction and lymphoid hyperplasia in the appendix lumen of 5 cases.No mortality was observed.Conclusions:The ratio of acute appendicitis caused by plants is minimal among all appendectomised patients, but avoidence of eating undigested fruit seeds and chewing plants well may help to prevent appendicitis.

Regulation of nitric oxide donor JS-K on tumor energy metabolism in H22 tumor-bearing mice

OBJECTIVE To investigate the regulation of {O^2(2,4-dinitrophenyl)1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate}(JS-K),anitric oxide donor,on tumor energy metabolism in H22 tumor-bearing mice.METHODS The hepatoma animal model in BALB/c mice was established with H22 cell line.The JS-K group and model group were received JS-K(0.75 and 1.5 mg?kg^(-1)) and saline via tail intravenous once every 3 d for 14 d,received 5 injections,respectively.The positive group was received 5-FU 20 mg·kg^(-1) by intraperitoneal injection once a day for 14 d.On the 15 th day mice were sacrificed.The tumor growth inhibition rate were calculated.The activities of hexokinase(HK),phosphofructo kinase(PFK),pyruvate kinase(PK),succinate dehydrogenase(SDH),adenosine triphosphatase(ATPase),and the levels of lactic acid(LD) and adenosine triphosphate(ATP) in tumor tissues were determined by colorimetric method.RESULTS Compared with model group,the tumor mass of JS-K0.75 and 1.5 mg·kg^(-1) group was significantly reduced(P<0.01),and the tumor growth inhibition rate was 23.9% and 50.3%,respectively.The activity of HK,PFK,PK,SDH and ATPase of tumor tissue in model group was(22.6±3.7,14.4±2.6,12.9±3.2 and 10.5±2.6)U·g^(-1) protein and(0.70±0.10)μmol Pi·mg^(-1) protein per hour,respectively;which in JS-K 1.5 mg?kg^(-1) group was dropped by 42.0%,26.6%,22.7%,23.3% and 21.7%(P<0.01,P<0.05).Compared with the model group,the level of ATP and LD in JS-K group was dropped(P<0.01).CONCLUSION JS-K can inhibit the growth of tumor in H22 tumor-bearing mice and its mechanism may be related to regulating the tumor energy metabolism with inhibition of glycolysis and aerobic oxidation.

Japanese herbal medicine, Saiko-keishi-to, prevents gut ischemia/reperfusion-induced liver injury in rats via nitric oxide

AIM: To determine whether Saiko-keishioto (TJ-10), a Japanese herbal medicine, could protect liver injury induced by gut ischemia/reperfusion (I/R), and to investigate the role of NO.METHODS: Male Wistar rats were exposed to 30-min gut ischemia followed by 60 min of reperfusion. Intravital microscopywas used to monitor leukocyte recruitment. Plasma tumor necrosis factor (TNF) levels and alanine aminotransferase (ALT) activities were measured. T]-10 1 gl(kg.d) was intragastrically administered to rats for 7 d. A NO synthase inhibitor was administered.RESULTS: In control rats, gut I/R elicited increases in the number of stationary leukocytes, and plasma TNF levels and ALT activities were mitigated by pretreatment withT]-10. Pretreatment with the NO synthase inhibitor diminished the protective effects of TJ-10 on leukostasis in the liver, and the increase of plasma TNF levels and ALT activities. Pretreatment with TL-10 increased plasma nitrite/nitrate levels.CONCLUSION: TJ-10 attenuates the gut I/R-induced hepalJc microvascular dysfunction and sequential hepatocellular injury via enhancement of NO production.

Novel Solid State Nitric Oxide Sensor Using Siloxane-Poly(Oxypropylene)(PPO)

In this paper, a novel solid state Nitric Oxide (NO) sensor made of a spin trap (iron(II)-diethyldithiocarbamate complex, FeDETC) encapsulated in a siloxane-poly(oxypropylene) (PPO) matrix was developed. Nitric oxide (NO), a free radical molecule, has numerous roles in various physiological functions, such as the regulation of blood pressure, immune response to bacterial infection, and nervous systems. Siloxane-polyether hybrid materials, for example siloxane-poly(oxypropylene) (PPO), are easy to prepare, transparent and flexible. The combination of all these characteristics in a unique material allows it to be used in several scientific and technological areas, including human health. NO radical is trapped in FeDETC, which allows its detection by electron paramagnetic resonance (EPR). FeDETC was added while PPO was a sol, which was then left in air for gelation. The novel sensor was dived directly into a solution of NO, when the NO-FeDETC complex was formed. Our results show that the novel sensor responds to NO, with similar sensitivity as previously published sensors. PPO sensors present a strong EPR signal and a high stability, keeping its signal for 45 days. We have studied ways to accelerate the NO release from the sensor, in order to study its potential as a drug delivery system. We observed an acceleration in NO release by using a modulated magnetic field of 40 G at 100 kHz;as well as by UV irradiation. Thermal induced NO release was also tested by heating NO-FeDETC PPO up to 50°C, with good results.

Non-cropping period accounting for over a half of annual nitric oxide releases from cultivated calcareous-soil alpine ecosystems with marginally low emission factors

草地农垦种植饲料作物,是高寒牧区的一种传统生产方式。而关于其一氧化氮(NO)排放特征与规律,目前知之甚少。本研究在青藏高原东北隅开展了饲料燕麦农田周年连续田间试验,对施肥(F)与对照(UF)处理的NO通量及主要环境因子进行了观测。结果表明:犁耕导致的排放占生长季排放量的54%–73%;非生长季占年排放量的51%–58%;年直接排放系数(EF_d)为0.021%±0.021%;施肥显著降低NO排放的温度敏感性(p<0.01);土壤水热条件和碳氮底物浓度共同解释NO通量变异的72%(p<0.01)。EF_d值可能主要取决于施基肥后一段时间(10 d左右)内的土壤湿度水平,需进一步研究来证实。

The Nongenomic Effects of Progesterone in Repressing iNOS Activation through P38MAPK Pathways in Gonococci-Infected Polymorphonuclear Leukocytes and the Clinical Significance

Progesterone has nongenomic effects on inducible nitric oxide synthase(iNOS),which is mediated by mitogen activated protein kinase(MAPK)pathways.This effect is supposed to have some potential association with asymptomatic gonococcal infections in women by immunological depression.In this study,polymorphonuclear leukocytes(PMNs)challenged by gonococci were used to study the nongenomic effects of progesterone.The activation of iNOS was assessed by measuring [3H] L-arginine converses to [3H] L-citrulline,and t...

Effects of NO and Different Media on the Growth of Prorocentrum micans

Prorocentrum micans was cultivated in different media including f/2, f/4, f/8, f/20, f/25, f/50, f/100 and f/200. Results showed that media influence the growth of P.micans. The biomass of P.micans in rich nutrition medium was much higher than in poor nutrition medium. Nitric oxide can promote or inhibit the growth of P.micans in all media. Nitric oxide at the concentration of 1.4×10 -6 mol L -1 promoted the growth of P.micans significantly when added only once during the cultivation. When added twice a day, nitric oxide at the concentration of 1.4×10 -9 mol [KG-*4]L -[KG-*5]1 promoted the growth of P.micans significantly, while nitric oxide at the concentrations of 1.4×10 -5 mol L -1 and 1.4×10 -6 mol L -1 inhibited the growth. Therefore, nitric oxide, media and the ways to add nitric oxide influenced the growth of P.micans respectively.

Cytoprotective and anti-inflammatory effects of kernel extract from Adenanthera pavonina on lipopolysaccharide-stimulated rat peritoneal macrophages

Objective:To investigate mechanism of anti-inflammatory activity of Adenanthera pavonina(A.pavonina) extracts.Methods:Rat peritoneal macrophages were treated with different concentrations of lipopolysaccharide and H_2O_2 in the presence and absence of kernel extract from A.pavonina.Nitric oxide,superoxide anion generation,cell viability and nuclear fragmentation were investigated.Results:The pre-treatment of kernel extract from A.pavonina suppressed nitric oxide,superoxide anion,cell death,nuclear fragmentation in lipopolysaccharide and H_2O_2stimulated or induced macrophages,respectively.Conclusions:These results suggest that A.pavonina extract suppresses the intra cellular peroxide production.

Hemodynamic Effects of Inhaled Nitric Oxide in Patients with Pulmonary Hypertension.

Twelve patients with pulmonary hypertension (primary pulmonary hypertension in 3 cases, secondary to recurrent pulmonary embolism in 4 cases, chronic obstructive pulmonary disease in 2 cases and complicated with congeni-