Inducible nitric oxide synthetase genotype and Helicobacter pylori infection affect gastric cancer risk

AIM： To investigate the association of the inducible ni- tric oxide synthetase （iNOS） C150T polymorphism with Helicobacter pylori （H. pylor/） infection and gastric can- cer （GC） risk in Iran. METHODS： In order to determine whether there was a correlation between iNOS genotype and GC in Iran, we conducted a case-control study using samples from 329 individuals. For each sample, the C150T ilVOS poly- morphism was genotyped by polymerase chain reaction （PCR） and restriction digestion. Patients were grouped by cancer presence, demographic and behavior charac- teristics, and/-/, pylori infection status. Statistical tests were conducted to determine whether any behavioral factors or a particular iNOS genotype was associated with GC in the study population. RESULTS： In this population, we found that smok- ing, hot beverage consumption, a familial history of GC and H. pylori infection status were significantly associated with GC development （P = 0.015, P 〈 0.001, P = 0.0034, and P 〈 0.015, respectively）. The distribution of the C150T ilVOS genotypes among the two study groups was not statistically significant alone, but was impacted by H. pylori infection status. When compared to the non-/-/, pylori infected group, cancer patients who had a heterozygous CT genotype and were also infected with H. pylori were 2.1 times more at risk of developing GC [odds ratio （OR） = 2.1, P = 0.03] while those with a homozygous TT genotype and infected with H. pylori were 5.0 times more at risk of developing GC （OR = 5.0, P = 0.029）. In contrast, this association was not seen in patients in the control group.CONCLUSION： ACT or TT polymorphism at position 150 in the iNO$ gene significantly increases the risk of GC and may be a marker for GC susceptibility.

In situ RT-PCR detection of inducible nitric oxide synthetase gene expression in lung during endotoxemia in rabbits

To detect the location of inducible nitric oxide synthetase (iNOS) protein and mRNA in lung during endotoxemia in rabbits Methods Northern blotting was performed before, 1 hour and 5 hours after the intravenous administration of lipopolysaccharide (LPS) in rabbits Immuno^histochemical analysis (IA), in situ hybridization and in situ reverse transcription polymerase chain reaction (in situ RT PCR) were also performed in lung sections Results iNOS mRNA expression was found using Northern blotting in lung 5 hours after LPS injection, while it was not found in control The positive stain was found only in macrophages in lung 5 hours after LPS injection by standard hybridization and IA; while by in situ RT PCR, the amplification products were found in macrophages, airway epithelial cells, vascular endothelial cells, smooth muscle cells and leukocytes, in addition to macrophages distributed abundantly throughout the lung The signal was absent in control or samples Conclusions Using an in situ RT PCR technique, iNOS expression was not only observed in macrophages but also in many other kinds of cells in lung during endotoxemia in rabbits This suggests that in situ RT PCR is much more sensitive than in situ hybridization, and can be used to examine genes with low expression