This study investigated the effects of combined minimal concentrations of quercetin and pioglitazone on angiotensin II-induced contraction of the aorta from fructose-streptozotocin (F-STZ)-induced type 2 diabetic rats and the possible role of superoxide anions (O2(-)) and nitric oxide (NO) in their potential therapeutic interaction. Contractile responses to Ang II of aortic rings from Sprague-Dawley (SD) and F-STZ rats were tested following pre-incubation of the tissues in the vehicle (DMSO; 0.05%), quercetin (Q, 0.1 μM), pioglitazone (P, 0.1 μM) or their combination (P + Q; 0.1 μM each). The amount of superoxide anion was evaluated by lucigenin-enhanced chemiluminescence and dihydroethidium fluorescence, and NO by assay of total nitrate/nitrite, and 4-Amino-5-Methylamino-2',7'-Difluorofluorescein (DAF-FM) diacetate. The synergistic reduction of Ang II-induced contraction of diabetic but not normal aorta with minimally effective concentrations of P + Q occurs through inhibiting O2(-) and increasing NO bioavailability. This finding opens the possibility of maximal vascular protective/antidiabetic effects with low dose pioglitazone combined with quercetin, thus minimizing the risk of adverse effects.
Biofouling is a crucial factor in membrane bioreactor (MBR) applications, particularly for high organic loading operations. This paper reports a study on biofouling in an MBR to establish a relationship between critical flux, Jc, mixed liquor suspended solids (MLSS) (ranging from 5 to 20 g L-1) and volumetric loading rate (6.3 kg COD m-3 h-1) of palm oil mill effluent (POME). A lab-scale 100 L hybrid MBR consisting of anaerobic, anoxic, and aerobic reactors was used with flat sheet microfiltration (MF) submerged in the aerobic compartment. The food-to-microorganism (F/M) ratio was maintained at 0.18 kg COD kg-1 MLSSd-1. The biofouling tendency of the membrane was obtained based on the flux against the transmembrane pressure (TMP) behaviour. The critical flux is sensitive to the MLSS. At the MLSS 20 g L-1 the critical flux is about four times lower than that for the MLSS concentration of 5 g L-1. The results showed high removal efficiency of denitrification and nitrification up to 97% at the MLSS concentration 20 g L-1. The results show that the operation has to compromise between a high and a low MLSS concentration. The former will favour a higher removal rate, while the latter will favour a higher critical flux.
Nitrate reduotase is induced by nitrate in excised embryos and germinating intact seedlings of rice (Oryza sativa L.). The enzyme is induced 24 hr after imbibition. The rate of enzyme formation increases with the age of seedlings. There is a lag period of 30 to 40 min between the addition of substrate and the formation of nitrate reductase. Formation of the enzyme is promoted by the presence of ammonium. Chloramphenicol, actinomycin D and cycloheximide effectively inhibit the formation of nitrate reductase.Rice seedlings can assimilate nitrate from the beginning of germination. However, the utilization of nitrate is completely suppressed by the presence of ammonium. As soon as ammonium is depleted from the medium, nitrate utilization is resumed. Ammonium inhibits the first step of nitrate reduction, i.e., NO(-) (3) --> NO(-) (2), but does not inhibit the assimilation of nitrite. This provides an example of feedback inhibition in higher plants.
The aim of the present study was to test the hypothesis that the proliferation of a human osteoblast cell line (HOS cells) stimulated with hydroxyapatite (HA) may be regulated by nitric oxide (NO). The cells were cultured on the surface of HA. Medium or cells alone were used as controls. L-arginine, D-arginine, 7-NI (an nNOS inhibitor), L-NIL (an iNOS inhibitor), L-NIO (an eNOS inhibitor) or carboxy PTIO, a NO scavenger, was added in the HA-exposed cell cultures. The cells were also precoated with anti-human integrin alphaV antibody. The levels of nitrite were determined spectrophotometrically. Cell proliferation was assessed by colorimetric assay. The results showed increased nitrite production and cell proliferation by HA-stimulated HOS cells up to day 3 of cultures. Anti-integrin alphaV antibody, L-NIO, or carboxy PTIO suppressed, but L-arginine enhanced, nitrite production and cell proliferation of HA-stimulated HOS cells. The results of the present study suggest, therefore, that interaction between HA and HOS cell surface integrin alphaV molecule may activate eNOS to catalyze NO production which, in turn, may regulate the cell proliferation in an autocrine fashion.
It is important to diagnose and treat urinary tract infection in children before renal damage has taken place. Hence a new screening procedure will be of interest. This study was conducted to evaluate the efficacy of urinary nitrite in screening for asymptomatic bacteriuria among school children compared to a more traditional method. Of the 44,816 school children investigated 240 (0.54%) students were judged to have bacteriuria ie 82 (0.19%) in boys and 158 (0.35%) in girls. Escherichia coli was the commonest organism isolated (28.75%). Urine dipstick testing for nitrite was found to have a low sensitivity and positive predictive value. While urinalysis for pyuria was noted to have a sensitivity of 77.9%, a specificity of 95.8% and a negative predictive value of 99.9%.
Nitrite, an anion produced from the oxidative breakdown of nitric oxide (NO), has traditionally been viewed as an inert molecule. However, this dogma has been challenged with the findings that nitrite can be readily reduced to NO under pathological conditions, hence representing a physiologically relevant storage reservoir of NO either in the blood or tissues. Nitrite administration has been demonstrated to improve myocardial function in subjects with heart failure and to lower the blood pressure in hypertensive subjects. Thus, extensive amount of work has since been carried out to investigate the therapeutic potential of nitrite in treating cardiovascular diseases, especially hypertension. Studies done on several animal models of hypertension have demonstrated the efficacy of nitrite in preventing and ameliorating the pathological changes associated with the disease. This brief review of the current findings aims to re-evaluate the use of nitrite for the treatment of hypertension and in particular to highlight its role in improving endothelial function.
Excess levels of nitrite ion in drinking water interact with amine functionalized compounds to form carcinogenic nitrosamines, which cause stomach cancer. Thus, it is indispensable to develop a simple protocol to detect nitrite. In this paper, a Cu-metal-organic framework (Cu-MOF) with graphene oxide (GO) composite was synthesized by ultrasonication followed by solvothermal method and then fabricated on a glassy carbon (GC) electrode for the sensitive and selective determination of nitrite contamination. The SEM image of the synthesized Cu-MOF showed colloidosome-like structure with an average size of 8 μm. Interestingly, the Cu-MOF-GO composite synthesized by ultrasonic irradiation followed by solvothermal process produce controlled size of 3 μm colloidosome-like structure. This was attributed to the formation of an exfoliated sheet-like structure of GO by ultrasonication in addition to the obvious influence of GO providing the oxygen functional groups as a nucleation node for size-controlled growth. On the other hand, the composite prepared without ultrasonication exhibited 6.6 μm size agglomerated colloidosome-like structures, indicating the crucial role of ultrasonication for the formation of size-controlled composites. XPS results confirmed the presence of Cu(II) in the as-synthesized Cu-MOF-GO based on the binding energies at 935.5 eV for Cu 2p3/2 and 955.4 eV for Cu 2p1/2. The electrochemical impedance studies in [Fe(CN)6]3-/4- redox couple at the composite fabricated electrode exhibited more facile electron transfer than that with Cu-MOF and GO modified electrodes, which helped to utilize Cu-MOF-GO for trace level determination of nitrite in environmental effluent samples. The Cu-MOF-GO fabricated electrode offered a superior sensitive platform for nitrite determination than the Cu-MOF and GO modified electrodes demonstrating oxidation at less positive potential with enhanced oxidation current. The present sensor detects nitrite in the concentration range of 1 × 10-8 to 1 × 10-4 M with the lowest limit of detection (LOD) of 1.47 nM (S/N = 3). Finally, the present Cu-MOF-GO electrode was successfully exploited for nitrite ion determination in lake and dye contaminated water samples.
The study of river water quality plays an important role in assessing the pollution status and health of the water bodies. Human-induced activities such as domestic activities, aquaculture, agriculture and industries have detrimentally affected the river water quality. Pinang River is one of the important rivers in Balik Pulau District that supplies freshwater for human consumption. A total of 442 physical and chemical parameters data of the Pinang River, Balik Pulau catchment were analysed to determine the sources of pollutants entering the river. Non-supervised artificial neural network (ANN) was employed to classify and cluster the river into upstream, middle-stream and downstream zones. The monitored data and non-supervised ANN analysis demonstrated that the source of nitrate was derived from the upper part of the Pinang River, Balik Pulau while the sources of nitrite, ammonia and ortho-phosphate are predominant at the middle-stream of the river system. Meanwhile, the sources of high total suspended solid and biological oxygen demand were concentrated at the downstream of the river.
Zamzam is holy water believed by Muslim to have remedial power for all kinds of diseases. It contains
many electrolytes and the concentration of the electrolytes may be affected by the types of container
used for its storage. This study was carried out to determine the difference in ions concentration of
Zamzam water stored in plastic and glass containers, and to determine cytotoxicity effects of Zamzam
water against U-87 cell line (human primary glioblastoma cell line). Ion Chromatography (IC) was used
to analyze the concentration. The analyzed anions in the Zamzam water include bromide, chloride,
phosphate, nitrite, nitrate, sulfate and fluoride whereas the cations were ammonium, lithium, potassium,
sodium, calcium and magnesium. Subsequently, MTT assay was used to determine the cytotoxicity of
Zamzam water on U-87 cell line. This study reveals that Zamzam water anions and cations
concentration was not statistically significant neither in plastic nor glass container. In addition, the
Zamzam water did not cause any toxicity on the U87 cell line. We postulate that types of container do
not have much influence on the ion concentration of Zamzam water and it is non-toxic on U87 cell line.
The purpose of research - to study the features of circadian profile of blood pressure (BP), the data of echocardiography, pH-monitoring, lipid spectrum, level of apelin and the state of the system "lipid peroxidation-antioxidant protection" in patients with a combination of arterial hypertension (AH) and gastroesophageal reflux disease (GERD) depending on the level of AH. It was examined 126 patients with combination of AH II stage, 2-3 degrees, and GERD, 70 (55.56%) men and 56 (44.44%) women, mean age 56.84 ± 1.17. The anthropometric indicators, a condition of "lipid peroxidation- antioxidant protection", the level of apelin, ambulatory blood pressure monitoring (ABPM), echocardiography, esophageal pH-monitoring were evaluated. Analysis of the results was performed using a computer program IBM SPSS Statistics 21.0 for Windows XP. According to the daily averages ABPM systolic BP/diastolic BP in the I group were 141.2 ± 0.8/90.4 ± 0.4 mm Hg., in II group - 163.3 ± 0.9/101.0 ± 0.5 mm Hg., in III group - 185.6 ± 0.8/112.1 ± 0.5 mm Hg., p = 0.001. There are only 25.39% of patients had normal indicators of the variability of BP among individuals with comorbidity. Transformation from mild AH to moderate was accompanied by a significant increase in the severity of left ventricular remodeling by type of concentric hypertrophy. The data of esophageal pH-monitoring allow us to classify the disorders as severe gastroesophageal reflux in patients with a combination of AH and GERD (DeMeester, 1993). In the group with first degree of AH the average rate of circulating apelin was 930.58 ± 56.27 pg/mL, for the patients with 2nd degree of AH - 880.56 ± 17.97 pg/ml, p>0.05, in patients with third degree of AH - 650.91 ± 12.87 pg/ml (p = 0.001). Assessment of lipid profile has allowed to establish the worse dyslipidemia in patients with 3rd degree of AH combined with GERD (atherogenic ratio - 3.11 ± 0.09). The deterioration of degree of AH combined with GERD accompanied by an increase of oxidative stress with increase of nitrites plasma and malondialdehyde concentration, and decrease of glutathione peroxidase and of SH-groups concentration. Increased degree of AH in patients with severe GERD accompanied by worsening of left ventricular remodeling, reduction of apelin levels, progression of dyslipidemia, and imbalances in the system of "lipid peroxidation-antioxidant protection."