Previous evidence supports the important role that oxidative stress (OxS) plays in metabolic syndrome (MetS)-related manifestations. We determined the relationship between the number of MetS components and the degree of OxS in MetS patients. In this comparative cross-sectional study from the LIPGENE cohort, a total of 91 MetS patients (43 men and 48 women; aged between 45 and 68 years) were divided into four groups based on the number of MetS components: subjects with 2, 3, 4 and 5 MetS components (n=20, 31, 28 and 12, respectively). We measured ischemic reactive hyperemia (IRH), plasma levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), total nitrite, lipid peroxidation products (LPO), hydrogen peroxide (H2O2), superoxide dismutase (SOD) and glutathione peroxidase (GPx) plasma activities. sVCAM-1, H2O2 and LPO levels were lower in subjects with 2 or 3 MetS components than subjects with 4 or 5 MetS components. IRH and total nitrite levels were higher in subjects with 2 or 3 MetS components than subjects with 4 or 5 MetS components. SOD and GPx activities were lower in subjects with 2 MetS components than subjects with 4 or 5 MetS components. Waist circumference, weight, age, homeostatic model assessment-beta, triglycerides (TGs), high-density lipoprotein and sVCAM-1 levels were significantly correlated with SOD activity. MetS subjects with more MetS components may have a higher OxS level. Furthermore, association between SOD activity and MetS components may indicate that this variable could be the most relevant OxS biomarker in patients suffering from MetS and could be used as a predictive tool to determine the degree of the underlying OxS in MetS.
Aged ; Anthropometry ; Antioxidants/metabolism ; Biological Markers/metabolism ; Blood Pressure ; Endothelium, Vascular/pathology/physiopathology ; Female ; Glutathione Peroxidase/blood ; Humans ; Hydrogen Peroxide/metabolism ; Hyperemia/blood/physiopathology ; Male ; Metabolic Syndrome X/blood/enzymology/*pathology/physiopathology ; Middle Aged ; Nitrites/blood ; *Oxidative Stress ; Regression Analysis ; Superoxide Dismutase/blood ; Vascular Cell Adhesion Molecule-1/metabolism

BACKGROUNDSalivary nitrate is positively correlated with plasma nitrate and its level is 9 times the plasma level after nitrate loading. Nitrate in saliva is known to be reduced to nitrite by oral bacteria. Nitrate and nitrite levels in saliva are 3 - 5 times those in serum in physiological conditions respectively in our previous study. The biological functions of high salivary nitrate and nitrite are still not well understood. The aim of this in vitro study was to investigate the antimicrobial effects of nitrate and nitrite on main oral pathogens under acidic conditions.

METHODSSix common oral pathogens including Streptococcus mutans NCTC 10449, Lactobacillus acidophilus ATCC 4646, Porphyromonas gingivalis ATCC 33277, Capnocytophaga gingivalis ATCC 33624, Fusobacterium nucleatum ATCC 10953, and Candida albicans ATCC 10231 were cultured in liquid medium. Sodium nitrate or sodium nitrite was added to the medium to final concentrations of 0, 0.5, 1, 2, and 10 mmol/L. All of the microorganisms were incubated for 24 to 48 hours. The optical densities (OD) of cell suspensions were determined and the cultures were transferred to solid nutrient broth medium to observe the minimum inhibitory concentration and minimum bactericidal/fungicidal concentration for the six tested pathogens.

RESULTSNitrite at concentrations of 0.5 to 10 mmol/L had an inhibitory effect on all tested organisms at low pH values. The antimicrobial effect of nitrite increased with the acidity of the medium. Streptococcus mutans NCTC 10449 was highly sensitive to nitrite at low pH values. Lactobacillus acidophilus ATCC 4646 and Candida albicans ATCC 10231 were relatively resistant to acidified nitrite. Nitrate at the given concentrations and under acidic conditions had no inhibitory effect on the growth of any of the tested pathogens.

CONCLUSIONNitrite, at a concentration equal to that in human saliva, is both cytocidal and cytostatic to six principal oral pathogens in vitro, whereas nitrate at a similar concentration has no antimicrobial effect on these organisms.

Anti-Infective Agents ; pharmacology ; Candida albicans ; drug effects ; Fusobacterium nucleatum ; drug effects ; Hydrogen-Ion Concentration ; Lactobacillus acidophilus ; drug effects ; Microbial Sensitivity Tests ; Mouth ; microbiology ; Nitrates ; analysis ; blood ; pharmacology ; Nitrites ; analysis ; blood ; pharmacology ; Porphyromonas gingivalis ; drug effects ; Saliva ; chemistry ; Streptococcus mutans ; drug effects

AIMTo establish a fluorospectrophotometric assay for the measurement of nitrite in blood.

METHODSInterference from hemoglobin and other blood ingredients was removed through sulfuric acid and phosphotungstic acid pretreatment. Fluorescence of 1-[H]-naphthotriazole from the reaction of 2,3-diaminonaphthalene with nitrite was determined with fluorospectrophotometry.

RESULTSThe following conditions were proper: Serum or plasma was treated with sulfuric acid and phosphotungstic acid pretreatment for two times, 2,3-diaminonaphthalene of 0.63 mmol x (L(-1)) was used, reaction solution pH and final pH were about 1.60 and 1.70 respectively, solution containing 2,3-diaminonaphthalene and supernatant after pretreatment was water-bathed at 20 degrees C for 15 minutes. The lower limit of detection was 24.27 nmol x L(-1). Nitrite determined in peripheral blood of healthy people was (10.91 +/- 2.38) micromol x L(-1), and its 95% distribution range was (6.24-15.57) micromol x L(-1).

CONCLUSIONIt's a relatively sensitive, specific, simple method. It's of some value to the study of nitric oxide.

Fluorophotometry ; Humans ; Limit of Detection ; Nitrites ; blood

OBJECTIVE: To investigate the correlation between radiologic vascular dilatation and serum nitrite concentration and eNOS expression in the endothelial cell and pneumocyte in a rabbit model of hepatopulmonary syndrome induced by common bile duct ligation (CBDL). MATERIALS AND METHODS: Thin-section CT scans of the lung and pulmonary angiography were obtained 3 weeks after CBDL (n=6), or a sham operation (n=4), and intrapulmonary vasodilatation was assessed. The diameter and tortuosity of peripheral vessels in the right lower lobe by thin-section CT and angiography at the same level of the right lower lobe in all subjects were correlated to serum nitrite concentration and eNOS (endothelial nitric oxide synthase) expression as determined by immunostaining. RESULTS: The diameters of pulmonary vessels on thin-section CT were well correlated with nitrite concentrations in serum (r = 0.92, p < 0.001). Dilated pulmonary vessels were significantly correlated with an increased eNOS expression (r = 0.94, p < 0.0001), and the severity of pulmonary vessel tortuosity was found to be well correlated with serum nitrite concentration (r = 0.90, p < 0.001). CONCLUSION: The peripheral pulmonary vasculature in hepatopulmonary syndrome induced by CBLD was dilated on thin-section CT and on angiographs. Our findings suggest that peripheral pulmonary vascular dilatations are correlated with serum nitrite concentrations and pulmonary eNOS expression.
Angiography ; Animals ; Common Bile Duct/injuries ; Dilatation, Pathologic/radiography ; Disease Models, Animal ; Endothelium, Vascular/metabolism ; Hepatopulmonary Syndrome/etiology/*metabolism ; Ligation ; Lung/*blood supply/metabolism/*radiography ; Nitric-Oxide Synthase/*metabolism ; Nitrites/*blood ; Pulmonary Artery/radiography ; Rabbits ; Research Support, Non-U.S. Gov't ; Tomography, X-Ray Computed/methods

The monitoring of airway inflammation has assessed in bronchial asthma directly by sputum examination, and indirectly by measurements in peripheral blood. To investigate the diagnostic value of these two methods, we compared nitric oxide (NO) metabolites, eosinophils, and eosinophil cationic protein (ECP) in sputum and blood in patients with asthma and control subjects. Sputum and serum were obtained from fifteen patients with asthma, and then were examined before anti-asthma treatment, including steroid preparations. ECP was measured by fluoroimmunoassay. NO metabolites were assayed by using modified Griess reaction. Asthmatic patients, compared with control subjects, had significantly higher level of NO metabolites, higher proportion of eosinophils, and higher levels of ECP in sputum. Asthmatic patients, compared with control subjects, however, had significantly higher number of eosinophils, and were at higher levels of ECP in blood. FEV1, FEV1 /FVC was negatively correlated with sputum eosinophils. The area under receiver operating characteristic(ROC) curve showed that eosinophils in sputum are significantly accurate markers than NO metabolites in sputum and blood. These findings suggest that the proportion of eosinophils in sputum have more accurate diagnostic marker of asthmatic airway inflammation than NO metabolites in sputum in differentiating asthmatic patients from control subjects.
Adult ; Area Under Curve ; Asthma/*blood/*metabolism ; Blood Proteins/*metabolism ; Comparative Study ; Eosinophils/*metabolism ; Female ; Fluoroimmunoassay ; Human ; Inflammation ; Male ; Nitrates/metabolism ; Nitric Oxide/blood/*metabolism ; Nitrites/metabolism ; ROC Curve ; Ribonucleases/blood/*metabolism ; Sputum/*metabolism

OBJECTIVETo observe the effect of nitric oxide (NO) on the survival of a random pattern skin flap.

METHODSCaudal based random skin flaps (9 cm x 3 cm) were raised on the back of Wistar rats. Six methods were used in the experiment to observe the effect of NO synthase inhibitor L-NAME and NO synthase substrate L-arginine on flaps: image analysis technology; light and electron microscopic studies; enzyme histochemistry of NOS in flaps; concentration of NO2-/NO3- in plasma and wet/dry ratio of the flap tissue.

RESULTSSurvival area of flap in the L-arginine-treated group significantly increased (67.06 +/- 5.65)% (p < 0.01) whereas the area in the L-NAME-treated group significantly decreased (35.17 +/- 1.87)% (p < 0.01) compared with the control group (53.25 +/- 3.24)% at seven days after the operation. General and microscopic observations showed that pathological changes in the L-arginine-treated group were fewer. Abundant capillaries and fewer inflammatory cells were noticed in the L-arginine-treated group. Transmission Electron Microscopy (TEM) studies find endothelial swelling, thrombosis-formation and endothelial loss of contact with the basement membrane in the L-NAME treated group. Before operation, the serum NO concentrations were not significantly different in three groups (p > 0.05). After operation, NO concentration of the control group began to increase and reached to the top at the third day. L-Arg kept serum NO concentration in a higher level than the control. Enzyme histochemistry of NOS in flaps: microvessel intima in dermis, hair follicles, sweat glands and inflammatory cells showed oxford blue, more positive in flaps of the L-Arg treated group than the control group at the third day after operation. The flaps of L-NAME-treated group demonstrated negative or weak positive. Wet/dry ratio: twenty-four hours after flap elevation wet/dry weight ratios increased significantly in all regions of the flap of the L-arginine-treated rats compared with saline-treated rats. The ratios of the flaps of L-NAME-treated rats were reduced compared with saline-treated rats.

CONCLUSIONNO could improve microcirculation of the flap and increase its survival rates. The mechanism might be that NO could accelerate flap vascularization and protect flaps from ischemia-reperfusion injury.

Animals ; Arginine ; pharmacology ; Dermatologic Surgical Procedures ; Enzyme Inhibitors ; pharmacology ; Female ; Graft Survival ; drug effects ; Immunohistochemistry ; Male ; Microscopy, Electron ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitrates ; blood ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; antagonists & inhibitors ; metabolism ; Nitrites ; blood ; Rats ; Rats, Wistar ; Skin ; enzymology ; ultrastructure ; Skin Transplantation ; Surgical Flaps ; physiology

Ischemic-reperfusion injury (IRI) is thought to be caused by oxygen radicals. Nitric oxide (NO) also has been thought to play a key role in IRI. This experiment was designed to evaluate the effects of antioxidants and NO supplement on hepatic IRI. Male Sprague-Dawley rats were divided into five groups: a sham operation group, a group with IRI, and three groups with vitamin C combined with vitamin E (VC&VE), L-arginine and N(G)-nitro-L-arginine (NNLA) injected after IRI. IRI was induced by clamping of the porta hepatis for 30 minutes and then by declamping. To prevent mesenteric blood congestion, a porto-systemic shunt had been made four weeks before the portal clamping. Biochemical assays of TNF-alpha level and NO2- level in the blood, malondialdehyde level, catalase activity and NO synthase activity in the liver tissue were performed. The results were as follows: IRI increased the malondialdehyde level and exhausted the catalase activity remarkably. VC&VE lowered the malondialdehyde levels and protected against catalase exhaustion, but had no significant effect on the NO production. L-arginine had a definite antioxidant effect, which was much weaker than that of VC&VE. In conclusion, antioxidants and a supplement of NO protected the liver tissue against IRI.
Animals ; Antioxidants/*metabolism ; Arginine/metabolism ; Ascorbic Acid/metabolism ; Catalase/metabolism ; Enzyme Inhibitors/metabolism ; Liver/*metabolism/pathology ; Male ; Malondialdehyde/metabolism ; Nitric Oxide/*metabolism ; Nitric Oxide Synthase/metabolism ; Nitric Oxide Synthase Type II ; Nitrites/blood ; Nitroarginine/metabolism ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury/*metabolism ; Tumor Necrosis Factor-alpha/metabolism ; Vitamin E/metabolism

The present study was aimed at investigating whether an altered role of nitric oxide (NO) is involved in chronic renal failure (CRF). Rats were subjected to 5/6 nephrectomy and kept for 6 weeks to induce CRF. On the experimental day, after measurement of arterial pressure under anesthesia, the arterial blood was collected, and thoracic aorta and kidney were rapidly taken. NO metabolites (NOx) were determined in the plasma, urine, aorta and kidney. The expression of NO synthase (NOS) isozymes was determined in the kidney and aorta by Western blot analysis. The expression of NOS mRNA in the glomeruli was also determined by RT-PCR. There were significant increases in arterial pressure and serum creatinine levels in CRF. Urine NOx levels were decreased in CRF, whereas plasma NOx levels were not altered. Aorta and kidney tissue NOx levels were also decreased in CRF. The expression of endothelial constitutive (ec) and inducible (i) isoforms of NOS proteins was decreased in the kidney and aorta in CRF. Accordingly, the expression of ecNOS and iNOS mRNA was decreased in the glomeruli in CRF. In conclusion, NO synthesis is decreased in the kidney and vasculature of CRF rats.
Animal ; Aorta, Thoracic/metabolism ; Comparative Study ; Enzyme Induction ; Isoenzymes/metabolism+ACo- ; Isoenzymes/genetics ; Kidney/metabolism ; Kidney Failure, Chronic/metabolism+ACo- ; Male ; Nephrectomy ; Nitrates/urine ; Nitrates/blood ; Nitric Oxide/deficiency+ACo- ; Nitric Oxide/biosynthesis ; Nitric-Oxide Synthase/metabolism+ACo- ; Nitric-Oxide Synthase/genetics ; Nitrites/urine ; Nitrites/blood ; Organ Specificity ; RNA, Messenger/biosynthesis ; Rats ; Rats, Sprague-Dawley

The present study was aimed at investigating whether an altered role of nitric oxide (NO) is involved in chronic renal failure (CRF). Rats were subjected to 5/6 nephrectomy and kept for 6 weeks to induce CRF. On the experimental day, after measurement of arterial pressure under anesthesia, the arterial blood was collected, and thoracic aorta and kidney were rapidly taken. NO metabolites (NOx) were determined in the plasma, urine, aorta and kidney. The expression of NO synthase (NOS) isozymes was determined in the kidney and aorta by Western blot analysis. The expression of NOS mRNA in the glomeruli was also determined by RT-PCR. There were significant increases in arterial pressure and serum creatinine levels in CRF. Urine NOx levels were decreased in CRF, whereas plasma NOx levels were not altered. Aorta and kidney tissue NOx levels were also decreased in CRF. The expression of endothelial constitutive (ec) and inducible (i) isoforms of NOS proteins was decreased in the kidney and aorta in CRF. Accordingly, the expression of ecNOS and iNOS mRNA was decreased in the glomeruli in CRF. In conclusion, NO synthesis is decreased in the kidney and vasculature of CRF rats.
Animal ; Aorta, Thoracic/metabolism ; Comparative Study ; Enzyme Induction ; Isoenzymes/metabolism+ACo- ; Isoenzymes/genetics ; Kidney/metabolism ; Kidney Failure, Chronic/metabolism+ACo- ; Male ; Nephrectomy ; Nitrates/urine ; Nitrates/blood ; Nitric Oxide/deficiency+ACo- ; Nitric Oxide/biosynthesis ; Nitric-Oxide Synthase/metabolism+ACo- ; Nitric-Oxide Synthase/genetics ; Nitrites/urine ; Nitrites/blood ; Organ Specificity ; RNA, Messenger/biosynthesis ; Rats ; Rats, Sprague-Dawley

We investigated to see whether an altered role of nitric oxide (NO) system is involved in erythropoietin (EPO)-induced hypertension in chronic renal failure (CRF). Male Sprague-Dawley rats were five-sixths nephrectomized to induce CRF. Six weeks after the operation, EPO or vehicle was injected for another 6 weeks. Plasma and urine nitrite/nitrate (NOx) levels were determined. Expression of NO synthase (NOS) proteins in the aortae and kidneys were also determined. In addition, the isometric tension of isolated aorta in response to acetylcholine and nitroprusside was examined. Blood pressure progressively rose in CRF groups, the degree of which was augmented by EPO treatment. Plasma NOx levels did not differ among the groups, while urine NOx levels were lower in CRF groups. Endothelial NOS expression was lower in the kidney and aorta in CRF rats, which was not further affected by EPO-treatment. The inducible NOS expression in the kidney and aorta was not different among the groups. Acetylcholine and sodium nitroprusside caused dose-dependent relaxations of aortic rings, the degree of which was not altered by EPO-treatment. Taken together, EPO-treatment aggravates hypertension in CRF, but altered role of NO system may not be involved.
Acetylcholine/pharmacology ; Anemia/metabolism ; Anemia/etiology ; Anemia/drug therapy* ; Animal ; Aorta, Thoracic/physiology ; Body Weight ; Erythropoietin/pharmacology* ; Hypertension, Renal/metabolism ; Hypertension, Renal/drug therapy ; Isometric Contraction/drug effects ; Kidney/enzymology ; Kidney Failure, Chronic/metabolism* ; Kidney Failure, Chronic/complications ; Male ; Nitrates/urine ; Nitrates/blood ; Nitric Oxide/metabolism* ; Nitric-Oxide Synthase/metabolism ; Nitrites/urine ; Nitrites/blood ; Nitroprusside/pharmacology ; Rats ; Rats, Sprague-Dawley ; Vasoconstriction/drug effects ; Vasoconstrictor Agents/pharmacology ; Vasodilator Agents/pharmacology