Biological monitoring of environmental exposure to polycyclic aromatic hydrocarbons: 1-hydroxypyrene in urine of Turkish coke oven workers.
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Biomedical subjects
Publications and source records attributed to C Demiroglu.
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This paper investigates the relative role of the impairment of insulin secretion and action in the pathogenesis of Type 2 diabetes mellitus (T2DM). The parameters indicating insulin secretion and action were calculated from the data obtained during oral glucose tolerance test (OGTT), in 156 age- and sex-matched T2DM patients divided in 4 groups according to their body mass index (BMI, I = 20.0-24.9, II = 25.0-29.9, III = 30.0-39.9 and IV > 40.0 kg/m2). After obtaining baseline biomedical parameters (plasma glucose, serum insulin, cholesterol, HDL-cholesterol, triglycerides, BMI, and amount of fat tissue), the rates of insulin secretory capacity and insulin action were obtained from OGTT and compared between the T2DM patients with normal body weight and different grades of obesity. Beta-cell secretory capacity of the participants was found to be proportionally and significantly higher in graded obese than that of the normal body weight patients. The rates of hepatic as well as peripheral insulin resistance in obese groups proportionally and significantly rise in comparison with that of non-obese diabetics. In addition, these parameters are shown to be related to the body fat, presumably visceral in origin. In conclusion, hyperglycemia-hyperinsulinemia observed in obese and T2DM patients might be due, in part, to increased capacity of insulin secretion, and to exaggerated hepatic glucose production because of hepatic insulin resistance, respectively.
Lp(a) is a unique class of lipoprotein particles that exhibits a considerable size heterogeneity resulting from the size polymorphism of apo(a), its unique protein component. An elevated level of Lp(a) in plasma has been proposed to be a risk factor for premature development of coronary artery disease. To evaluate the relationship between Lp(a) concentration and apo(a) isoform size with restenosis after percutaneous transluminal coronary angioplasty, Lp(a) levels and apo(a) phenotypes were determined in 204 patients who underwent a successful coronary angioplasty procedure and stent implantation. The patients were followed with clinical examinations and exercise tests at 1, 3, and 6 months, and a control coronary angiography was performed after 6 months to evaluate restenosis. Lp(a) levels were determined with an ELISA that is insensitive to the size heterogeneity of Lp(a), and the apo(a) isoforms were determined by a high-resolution agarose gel electrophoresis method followed by immunoblotting with a specific monoclonal antibody. Of the 146 patients who underwent angiographic evaluation, 57 (39%) had restenosis, whereas 89 (61%) did not. Lp(a) levels and the distribution of the expressed apo(a) phenotypes were compared in these two groups of patients. Although the mean and median Lp(a) levels were higher in the restenosed group, the difference was not statistically significant. However, a significant difference in Lp(a) values was found in women (P=0.043), even though, because of the small number of women in the study (n=35), no sound conclusions can be reached on the predictive role of Lp(a) in restenosis. There also was no difference in the distribution of apo(a) phenotypes between the two groups. Because of their wide distribution, Lp(a) values and apo(a) isoforms do not seem to be a useful indicator of risk of restenosis after percutaneous transluminal coronary angioplasty in our study cohort.
The incidence of isolated ostial stenosis of the left main coronary artery varies between 0.13% and 2.7%. We performed surgical ostial angioplasty in five patients who had isolated left coronary ostial stenosis. One patient had low systemic blood pressure and, after the procedure, manifested myocardial ischaemia: conventional aortocoronary bypass was performed. The outcome of the four others was uneventful. They remained free of symptoms and resumed normal activities. Transaortic patch angioplasty might be useful operative method for the isolated coronary ostial stenosis, since it restores a more physiologic perfusion of the coronary arteries.
The effects of n-3 fatty-acid supplementation on serum lipids, platelet aggregation, and the development of atherosclerotic lesions were studied in the cholesterol-fed rabbit. Serum total cholesterol and LDL cholesterol values were significantly reduced in comparison with those of the nonsupplemented cholesterol-fed group (p less than 0.005, p less than 0.0025, respectively), though still higher than those of the control group (p less than 0.0025, p less than 0.0125 respectively). Platelet aggregation was reduced below that of the cholesterol-fed and the control levels (p less than 0.0005, p less than 0.0025, respectively). The endothelial injury encountered in cholesterol-fed rabbits was inhibited in the supplemented group. It is concluded that n-3 fatty acids suppress atherogenesis in this animal model by interfering with platelet aggregation and lipid metabolism.
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A randomized within-patient double-blind acute and sustained study was performed to compare transdermal nitroglycerin (NTG) patches (5 and 10 mg) and matching placebo in 10 patients with chronic stable angina pectoris confirmed on exercise thallium scintigraphy or coronary angiography, or both. Patients performed treadmill tests 2 and 24 hours after application of patches on the first and last days of each of the 3 treatment periods. Effects caused by sequence of treatments and training with serial testing were prominent so the changes in the well-known parameters did not favor either of the active doses over placebo. Quantification of training effects and its subtraction from performance index disclosed that 10 mg of transdermal NTG caused significant increase in performance in both the acute and sustained stages of therapy in comparison to pretreatment performance. This was not observed with 5 mg and placebo treatments. To our knowledge, this is the first trial to study the efficacy of transdermal NTG with a more objective parameter that permitted elimination of training effects of serial exercise testing.
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Erythrocytes from alcoholics without liver cirrhosis and control subjects were examined for the susceptibility to lipid peroxidation. Erythrocytes of patients were found to be sensitive to H2O2-induced peroxidation as compared to controls. In addition, chronic alcoholics showed a high level of plasma lipid peroxide levels. These results suggest the stimulation of lipid peroxidation in chronic alcoholics.
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