Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carcinoma of the urinary bladder is the most common malignancy in Egyptians. At the National Cancer Institute in Cairo, it accounts for 27.6% of all cancers--38.5% of cancers in the male and 11.3% in the female. This very high frequency is attributed to underlying schistosomiasis. The infection can lead to malignancy through local tissue damage, mechanical irritation, bilharzial toxins or through secondary bacterial infection. Bacterial products include nitrate reductase capable of synthesizing nitrosoamines and beta glucuronidase enzymes, active at pH 7. Through liver involvement and dysfunction, tryptophan metabolism is disturbed, with the excretion of carcinogenic metabolites. Vitamin A deficiency is responsible for the squamous metaplasia and the high frequency of squamous cell carcinoma observed in the bladder. The characteristic clinico-pathological features of cancer of the urinary bladder are outlined, mainly the occurrence at a young age, the male predominance, especially farmers, and the high association with schistosomiasis. The tumors are often first seen in an advanced stage, arising from the posterior bladder wall and vault. The trigone is only affected in 8.5% of the cases. Histologically, squamous cell carcinomas of low grade are the most frequent cell type. Lymph node involvement is low in spite of the advanced stage of the tumor. Therefore, the results of radical surgery are encouraging. The results of a special study correlating the above parameters with the intensity of ova deposition are presented. Patients with heavy infection at a slightly earlier age but other tumor parameters the same are similar to those of egg-negative cases. This study indicates that other factors also play a role in the induction of tumors that are enhanced by the schistosomal infection. In Fayoum Province, schistosomiasis is decreasing while bladder cancer is increasing. Urine cytology as a screening tool is effective in detecting early bladder cancer. Studies are now in progress to detect tumor associated antigens in sera and urine of patients.
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PMID:Carcinoma of the urinary bladder associated with schistosomiasis in Egypt: the possible causal relationship. 314 81

Detailed analyses of biochemical and microbiological variables such as pH, nitrite concentration, total viable counts (TVC), nitrate reductase-positive bacterial counts (NRPBC), and identification of microorganisms were carried out on 76 fasting gastric juice samples obtained at endoscopy from 64 patients previously submitted to partial gastrectomy (22 end-to-end Billroth I, 42 Billroth II/Reichel-Polya) and from 12 normal controls. Samples from normal controls were sterile, but bacteria were detected in the juice from all the operated patients. Significantly higher mean pH values and nitrite levels (p less than 0.001) were found in partial gastrectomies than in normal controls. In relation to surgical methods, higher mean pH values (p less than 0.005), nitrite levels (p less than 0.01), TVC (p less than 0.01), and NRPBC (p less than 0.005) were observed in the juice of patients with Billroth II as compared with Billroth I gastrectomies. Anaerobic bacteria, typical of faecal flora, and particularly Escherichia coli (p less than 0.05) characterized Billroth II samples. All these data suggest that the presence of bacteria in the gastric juice of gastroresected patients can be considered a risk factor of gastric neoplasia and that the type of operation used for the reconstruction of digestive continuity may influence the magnitude of this risk.
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PMID:The microflora of the gastric juice after Billroth I and Billroth II partial gastrectomy. 372 52

The aim of this study was to compare and improve standard methods to determine nitrite (NO2-), nitrate (NO3-) and S-nitrosothiol (RSNO) levels in cell culture supernatants, sera, and urine. We modified the conventional Griess reaction by replacing sulfanilamide with dapsone (4,4'-diamino-diphenylsulfone) and compared the NO2- levels in our study samples with a commercially available NO2- assay kit. Our modification, along with ultrafiltration of the samples, resulted in an enhanced sensitivity to measure NO2- down to 0.2 microM. The detection limit was further improved to 0.02 microM when NO2- was identified by the fluorochrome 2,3-diaminonaphthalene (DAN). To measure the stable end product NO3- by the Griess reaction or the DAN method, this anion must be reduced to NO2-. We compared the capacity of bacterial nitrate reductase with the reducing metal cadmium to convert NO3- to NO2-. After reduction, NO2- levels were determined either by the DAN method or by our modified Griess reaction. We found that there was a high correlation (r2 = 0.998) in total NO2- concentrations in the study samples using both methods for reducing NO3- to NO2-. The simultaneous determination of NO2- and NO3- was achieved by using anion-exchange chromatography (HPLC; Polyspher IC AN-1 column). The detection limit of this assay for each anion is 0.5 microM, and it can be applied equally well to sera, urine, and culture media. We also adapted the DAN method to determine RSNO levels in our study samples. Using this approach, we were able to measure RSNO levels down to 0.15 microM. As result we discovered that RSNO levels were markedly increased in urine from septic patients and in supernatants from cytokine-stimulated human tumor cell lines. L-Citrulline, a coproduct of NO biosynthesis, was measured using a colorimetric assay with a sensitivity limit of 3.0 microM. Increased L-citrulline levels in media from cultured cells, but not in sera or urine, correlated with increased NO production. Although all methods studied were suitable for quantifying end products of NO in biological fluids and media, the use of bacterial reductase and the modified Griess reaction proved successful to provide the greatest sensitivity and linear range for routine measurements of NO2- and NO3-.
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PMID:Improved methods to measure end products of nitric oxide in biological fluids: nitrite, nitrate, and S-nitrosothiols. 970 Oct 56

We report here on the obtainment of interspecific somatic, asymmetric, and highly asymmetric nuclear hybrids via protoplast fusion. Asymmetric nuclear hybrids were obtained after fusion of mesophyll protoplasts from a nitrate reductase-deficient cofactor mutant of N. plumbaginifolia with irradiated (100 krad) kanamycin resistant leaf protoplasts of a haploid N. tabacum. Selection for nitrate reductase (NR) and/or kanamycin (Km) resistance resulted in the production of three groups of plants (NR(+), NR(+), Km(R), and NR(-)Km(R)). Cytological analysis of some hybrid regenerants showed the presence of numerous tobacco chromosomes and chromosome fragments, besides a polyploid N. plumbaginifolia genome (tetra or hexaploid). All the regenerants tested were male sterile but some of them could be backcrossed to the recipient partner. In a second experiment, somatic and highly asymmetric nuclear hybrids were obtained after fusion of mesophyll protoplasts from the universal hybridizer of N. plumbaginifolia with suspension protoplasts of a tumor line of N. tabacum. Selection resulted in two types of colonies: nonregenerating hybrid calli turned out to be true somatic hybrids, while cytological analysis of regenerants obtained on morphogenic calli did not show any presence of donor-specific chromosomes. Forty percent of the hybrid regenerants were completely fertile, while the others could only be backcrossed to the recipient N. plumbaginifolia. Since the gene we selected for is not yet cloned, we were not able to demonstrate the transfer of genetic material at the molecular level. However, since no reversion frequency for the nitrate reductase mutant is known, and due to a detailed cytological knowledge of both fusion partners, we feel confident in speculating that intergenomic recombination between N. plumbaginifolia and N. tabacum has occurred.
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PMID:Metabolic complementation for a single gene function associated with partial and total loss of donor DNA in interspecific somatic hybrids. 2422 Sep 66