Yazar "Girgin F.K." seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Catalase and paraoxonase in hypertensive type 2 diabetes mellitus: Correlation with glycemic control
    (1999) Sözmen B.; Delen Y.; Girgin F.K.; Sözmen E.Y.
    Objectives: Type 2 diabetes mellitus (DM) is well recognized as being associated with increased prevalence of hypertension. Experimental and epidemiologic studies have shown that oxygen-free radicals are elevated because antioxidant enzyme activities are altered both in uncontrolled essential hypertension and DM itself. Recently paraoxonase (PON) has been recognized as an antioxidant enzyme that hydrolyzes lipid peroxides. The aim of this study is to evaluate simultaneously PON activities and antioxidant status in hypertensive type 2 DM cases and to establish any possible relationship between these parameters and duration of hypertension or diabetes, hemoglobin (Hb) A(1c) levels, and lipid parameters. Design and methods: Nineteen normotensive subjects with type 2 DM, 37 hypertensive (diastolic blood pressure 90 mm Hg or more) subjects with type 2 DM, and 25 normotensive control subjects with normal glucose tolerance were selected for this study. Superoxide dismutase (SOD), catalase, and basal-stimulated PON activities were measured by the methods of Sun et al.; Goth; and Eckerson, Wyte, and La Du, respectively; other lipid parameters were determined using an autoanalyzer. Results: Catalase activities of either hypertensive patients with type 2 DM or type 2 DM patients without complication were found to be higher than controls (p < 0.01), although no significant difference in SOD and basal-stimulated PON activities was observed between these groups. A significant elevation in catalase activity (p = 0.004) of patients with high HbA(1c) levels (>7.0%) (n = 37) compared with patients with low HbA(1c) levels (<7.0%) (n = 19) was detected. There was also a positive correlation between the catalase activities and fasting glucose levels and HbA(1c) concentrations in hypertensive patients with type 2 DM (r = 0.4567, p < 0.05 and r = 0.3686, p < 0.05, respectively). An increase in catalase activity of patients with B and/or AB phenotype compared with patients with A phenotype was also noted. Conclusion: Poor glycemic control in diabetes is strongly associated with an increase in free radicals and consequent diabetic complications. Uncontrolled glucose metabolism may also be the cause of alterations in antioxidant enzymes. Among these, catalase correlates best with poor glycemic control. The current data reveal that B allele carriers of PON are more susceptible to oxidant stress.
  • Küçük Resim Yok
    Öğe
  • Küçük Resim Yok
    Öğe
    MAO inhibitors in aging: Can they serve as protective agents in cardiac tissue against oxidative stress?
    (1999) Girgin F.K.; Ozgonul M.; Alper G.; Mentes G.; Ersoz B.; Sozmen E.Y.
    Biological damage mediated by reactive oxygen species has been increasingly recognized in aging phenomena in recent decades. The increase in catecholamine metabolism is yet another physiological change in aging, predisposing the organism to supranormal hydrogen peroxide production as a by-product. This study was undertaken to investigate the alterations in oxidant-antioxidant status in rat cardiac tissue during aging. The effects of acute administration of monoamine oxidase (MAO) inhibitors on this status were also investigated to find possible preventive strategies in conjugate aging. MAO activities, malondialdehyde MDA and diene conjugate levels as well as superoxide dismutase and catalase activities were determined in the cardiac tissues of young and aging groups, each consisting of 10 rats. MAO inhibitors (deprenyl and pargyline) were administered to another two groups of young and aging animals (10 in each group) and the same parameters were also determined in these groups. Cardiac tissue MAO activities (p<0.005) as well as diene conjugates (p<0.0001) and MDA levels (p<0.005) were found to be significantly higher in aging compared to young control groups. The increases in these parameters were all correlated. Acute MAO inhibitor administration caused significant decreases in MAO activities in both young (p<0.0005 with deprenyl and p<0.0001 with pargyline) and aging groups (p<0.0001 with deprenyl and p<0.00001 with pargyline). Parallel to this finding, diene conjugate and MDA levels were also found to be decreased after MAO administration. Although the aging control group had manifested a decrease in antioxidant enzymes; SOD and catalase (p<0.05, both), acute administration of MAO inhibitors did not induce any significant changes in these parameters. In conclusion, our experimental data suggest that catecholamine metabolism and MAO activity may play a role in the pathological alterations in the aging cardiac tissue by serving as an important source for increased lipid peroxidation, and inhibition of this activity may play a role in limiting the clinical sequelae of these alterations.