Effects of pharmacological modulation of protein kinase A, C and G (PKA, PKC and PKG) were examined on inducible form of nitric oxide synthase (iNOS) expressed in COS cells to elucidate regulatory mechanism of iNOS by protein kinases. Formation of nitric oxide (NO), as an index of NOS activity, was assessed by measurement of nitrite in incubation medium in long term observation and by hemoglobin assay method in kinetic study. In long term observation (18 hours), activation of PKA by 8-Br-cAMP increased NO formation that was inhibited by N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinolinesulfonamide (H89). Though activation of PKC by 12-O-tetradecanoyl phorbol-13-acetate (TPA) decreased NO formation, PKC inhibitor, chelerythrine, failed to inhibit the decrease. Activation of PKG with 8-Br-cGMP and inhibition with KT5823 resulted in no change in NO formation. Western blot analysis revealed that neither 8-Br-cAMP nor TPA affect iNOS expression. In kinetic study (short term perfusion study), no change in NO formation was observed by 8-Br-cAMP and TPA. These results indicate that, in living cells, PKG does not play a regulatory role in iNOS activity and that PKA and PKC do not directly modulate iNOS activity. However, PKA and PKC would possibly modify NOS activity indirectly via cofactors necessary for NO formation.
The present study reports the enzymatic and non-enzymatic antioxidant status and hepatic microsomal lipid peroxidation in chloramphenicol treated rats. Chloramphenicol at a dose of 28 mg/kg body weight orally administered to rats increased the activity of cytosolic superoxide dismutase by 63% while the activities of glutathione peroxidase and catalase were decreased by 57% and 44%, respectively. In vitro, chloramphenicol altered the activities of these enzymes though not as pronounced as the effect of the drug on the enzymes in vivo. The levels of serum vitamins A, C and β-carotene were significantly decreased following chloramphenicol treatment. Microsomal lipid peroxidation was markedly and significantly increased by chloramphenicol treatment. The drug elicited 69% and 71% increases in the levels of malondialdehyde and lipid hydroperoxide, respectively. Glutathione level and glutathione S-transferase activity were decreased by 42% and 58%, respectively, compared to untreated controls. Overall, the results of the present investigation indicate alteration of enzymatic and non-enzymatic antioxidant status and induction of lipid peroxidation by chloramphenicol. The clinical implications in the detoxification of toxic metabolites of lipid peroxidation caused by chloramphenicol warrant co-administration with antioxidant vitamins in chloramphenicol treatment regimen.
Oxidative DNA damage in peripheral white blood cell of smokers were estimated in accordance with the levels of 8-Hydroxydeoxyguanosine (8-OHdG) in nuclear DNA and the antioxidant status of these smokers' plasma was investigated in terms of the ex vivo oxidation resistance of plasma. In a survey of 12 smokers (4 women) aged 22 to 48, the mean level of 8-OHdG was 3.79±0.65 residue/106 dG (mean±S.D.) with a range from 2.83 to 4.62 residue/106 dG. These measurements showed approximately 1.6-fold inter-individual variations of 8-OHdG level in smokers. A higher level of 8-OHdG was found for smokers whose ex vivo plasma oxidation resistance was weak. Significant association is seen between oxidized bases in white blood cells and plasma oxidation resistance, whereas signs of any association with plasma concentration of α-tocopherol, ascorbic acid, bilirubin, and uric acid are weak and sporadic. These findings indicate that apparent heterogeneity exists among smokers in some sort of resistance to the oxidative effects of smoking.
To see how different foods were selected depending on family-togetherness at breakfast and dinner, we investigated the meals of eight thousand primary and four thousand junior high school students by questionnaire. About 70% of primary school children but less than 50% of junior high school children ate breakfast with their family. The food, eaten by children who ate meals together with their family, took more time for cooking and was more traditional with rice as the staple. Food eaten by children who did not eat with their family lacked both preparation time and staple base. Family-togetherness affects the foods of primary school children more than those of junior high school students.
The aim of this study is to examine the characteristics of nitrite/nitrate (NOx), the final metabolite of nitric oxides, in plasma after burn injury. A total of 83 blood samples were collected from 19 patients on arrival, day 1, day 3, and day 5 after suffering burn injuries and from 7 non-burned volunteers. We measured the NOx levels in plasma using the Griess method, and analyzed the relationships among plasma the NOx levels, the burn-magnitude, and the blood examination data using a stepwise multivariate regression analysis. The plasma NOx levels at hospital-arrival after burns significantly exceeded those of non-burned volunteers, and the NOx levels in the plasma returned to normal range after day 1. Based on the findings of a multivariate analysis, the plasma NOx levels at admission to the hospital were not found to be related to the total burn surface area, the burn index or inhalation injury, but they were significantly related to age. Furthermore, these plasma NOx levels were also related to the platelet count, neutrophil count and blood urea nitrogen. The increase in the plasma NOx level may therefore play an important role in the pathophysiology of elderly burned patients, while the nitric oxide levels in the plasma might also play a role in inhibiting the constriction of microvascular smooth muscle in extensively burned patients.
The percentages of Th1 and Th2 cells and the Th1 : Th2 ratios in peripheral blood from 22 patients with a singleton pregnancy at 30 and 36 weeks' gestation, on admission for the spontaneous onset of labor pains, at 1 minute after placental delivery and on day 7 after delivery were determined using flow cytometry. The percentages of Th1 and Th2 cells and the ratio of Th1 : Th2 did not markedly change during 30 weeks' gestation and 1 minutes after placental delivery. However, the percentage of Th2 cells had decreased significantly at 7 days after delivery. In addition, the Th1 : Th2 cell ratios were significantly elevated on day 7 after delivery. Thus, the termination of pregnancy may not be associated with a change in maternal Th1 : Th2-immunity.