Umit Karayalcin

The effect of body weight and weight loss on thyroid volume and function in obese women

objective Thyroid volume and thyroid function may vary in obese and nonobese women. It is not known whether weight loss could affect thyroid volume and function in obese subjects.

Activities of xanthine oxidoreductase and antioxidant enzymes in different tissues of diabetic rats

Oxidative stress is an important pathogenic constituent in diabetic endothelial dysfunction. The aim of this study was to investigate whether an increase in oxidative stress related to xanthine oxidoreductase occurs in diabetes. Liver, brain, heart, and kidney xanthine oxidase (XO), xanthine dehydrogenase (XDH), antioxidant enzymes (glutathione peroxidase, superoxide dismutase, catalase), and nitrite levels were measured in control and early and late diabetic rat models. Although diabetes had no impact on liver XO and XDH activity, XDH activity in heart, kidney, and brain was significantly greater in late diabetic rats than in controls. Selenium glutathione peroxidase (GPx) activity was found to be lower in the liver, brain, kidney, and heart of late diabetic rats than in controls. The measured decrease in selenium GPx activity was also observed in early diabetic heart, kidney, and brain. No significant change was observed in liver, brain, and kidney copper/zinc superoxide dismutase (Cu/Zn SOD) activity in early and late diabetic rat models compared with that in controls, whereas heart Cu/Zn SOD activity was significantly decreased in both early and late diabetic rats. Liver and brain catalase activity remained similar among the different experimental groups, whereas increased heart and kidney catalase activity was observed in both early and late diabetic rats. Liver, kidney, and brain nitrite levels were found to be increased in early diabetic rat models compared with those in controls. These data suggest that the increased XDH and decreased selenium GPx activity observed in the later stages of diabetes leads to enhanced oxidative stress in the heart, kidney, and brain, resulting in secondary organ damage associated with the disease.

Insulin resistance in chronic hepatitis C

Aim:  Insulin resistance (IR), glucose intolerance and diabetes mellitus are commonly associated with cirrhosis. The exact pathogenetic mechanisms responsible are still unknown; however, they may be related to both hepatitis C virus itself and to liver injury. IR may be the earliest abnormality, which in the following years may progress to clinical diabetes mellitus. The aim of this study was to investigate the presence of IR by euglycaemic hyperinsulinemic clamp technique, in chronic hepatitis C patients.

Erythrocyte, plasma, and serum antioxidant activities in untreated toxic multinodular goiter patients

Erythrocyte, plasma, and serum antioxidant activities were studied in patients with newly diagnosed and untreated toxic multinodular hyperthyroid goiter and compared to healthy control subjects. Erythrocyte antioxidant enzyme activities, glutathione, malondialdehyde, and ceruloplasmin levels were significantly increased, whereas serum vitamin E, plasma vitamin C, and selenium levels were decreased in hyperthyroid patients compared to control subjects. The findings show that untreated toxic multinodular goiter causes profound alterations in components of the antioxidant system in erythrocytes indicative of increased oxidative stress. Taken together, these data suggest that hyperthyroid patients may benefit from dietary supplements of antioxidants.

Comparison of Efficacy of Sibutramine or Orlistat Versus Their Combination in Obese Women

Objective: Sibutramine and orlistat are currently used for weight loss. We aimed to investigate the effect of orlistat and sibutramine combination therapy in treatment of obese women. Subjects and Design: Study population consisted of 89 obese women who had a body mass index ≥ 30 kg/m2, were normotensive, and had normal glucose tolerance. All patients were placed on a diet which contained fat approximately 30% of total calorie intake and the diet was designed to cause an energy deficit of approximately 2.51–3.56 megajoule/day. At the first month of diet (baseline), all patients were randomly divided into three therapy groups: Diet + Orlistat (group 1; n = 30 patients), Diet + Sibutramine (group 2; n = 29 patients), Diet + Orlistat + Sibutramine (group 3; n = 30 patients). Body weight, body fat distribution and serum lipid levels were evaluated baseline and after six months in all subjects. Results: Mean weight loss was 5.5 ± 4.9 kg (p = 0.024) in group 1, 10.1 ± 3.6 kg (p < 0.001) in group 2, 10.8 ± 6.6 kg (p < 0.001) in group 3 after the six months. Weight loss was significantly greater in group 2 (p = 0.003) and group 3 (p = 0.002) when compared with group 1. Percentage of mean weight loss was 5.5 ± 3.1% in group 1, 10.2 ± 4.8% in group 2, 10.6 ± 5.7% in group 3. Percentage of weight loss was higher in group 2 (p = 0.01) and group 3 (p = 0.009) when compared with group 1. Weight loss and percentage of weight loss were not different between group 2 and group 3. Conclusion: These three regimens had different results on weight loss in obese women. Combination drug therapy and sibutramine therapy were both more effective than orlistat therapy alone. However, no significant difference was noted between combination drug therapy and sibutramine treatment groups.

Clinical importance of antineutrophil cytoplasmic antibody positivity during propylthiouracil treatment.

Background:  Propylthiouracil (PTU) is the mainstay of antithyroid drug therapy. Previous studies reported antineutrophil cytoplasmic antibody (ANCA)‐positive vasculitis in patients treated for Graves’ disease. ANCA has been associated with either PTU or to the disease itself. However, this issue has not been investigated in toxic multinodular goitre (TMNG). The aim of this study was to evaluate the frequency of ANCA positivity in both TMNG and Graves’ disease patients treated with PTU, and to investigate the clinical importance of this issue.

Incidental Thyroid Carcinoma in Thyrotoxic Patients Treated by Surgery

Background and Aims: Thyroid malignancy detected incidentally in patients who are operated for thyrotoxicosis has been reported at different rates. The aim of this study was to investigate the rate of incidental thyroid carcinoma in thyrotoxic patients managed with surgery in our institution. Methods: Of the 375 thyrotoxic patients who had thyroid surgery between the years of 1997–2004, 70.7% were females and 29.3% were males. Among thyrotoxic patients 65.3% (n = 245) had toxic multinodular goiter (TMG), 16.8% (n = 63) had toxic adenoma (TA) and 17.9% (n = 67) had Graves’ disease. Results: Twenty-six (6.9%) of all thyrotoxic patients had thyroid carcinoma. Eighteen (7.3%) of TMG, 4 (6.3%) of TA and 4 (6%) of Graves’ disease patients had thyroid carcinoma. Histologic examination revealed 18 papillary (9 microscopic), 5 follicular, 2 hurthle cell and 1 anaplastic carcinoma. Conclusion: In our study, incidental thyroid carcinoma was found in 6.9% of subjects with thyrotoxicosis. Papillary thyroid microcarcinomas constituted 34.6% (26/9) of these newly diagnosed thyroid carcinomas. The incidence of thyroid carcinoma was not higher in subjects with Graves’ disease compared to TMG and TA. The rate of incidental thyroid carcinoma in subjects with thyrotoxicosis treated with surgery was similar to previous studies reported from different countries.

Hypocalcemic Cardiomyopathy due to Untreated Hypoparathyroidism

Hypocalcemic cardiomyopathy due to hypoparathyroidism is a very rare condition which is usually refractory to conventional treatment for cardiac failure but which responds favorably to restoration of normocalcemia. A 55-year-old man and a 46-year-old woman with a history of postoperative hypoparathyroidism presented with symptoms of cardiac failure and hypocalcemia. A presumptive diagnosis of dilated cardiomyopathy was considered by echocardiography and endomyocardial biopsies were consistent with cardiomyopathy. The coronary angiograms were normal and there was no apparent cause for dilated cardiomyopathy in these patients. The history of the patients and partial recovery of cardiac function after restoration of normocalcemia suggest that hypocalcemia was the cause of dilated cardiomyopathy.

Acute Effect of Exercise on Plasma Leptin Level and Insulin Resistance in Obese Women with Stable Caloric Intake

Obese individuals are frequently hyperleptinemic and insulin resistant. Chronic exercise is associated with improvements in plasma leptin level and insulin sensitivity; however, little is known about the acute effect of exercise on these parameters. The aim of this study was to evaluate the acute effect of aerobic exercise on plasma leptin and insulin sensitivity in obese women with stable caloric intake. Patients and Methods: Twenty-three obese women (age 41.2 ± 10.3 years, body mass index 40.7 ± 6.7 kg/m2) were included to the study. All subjects were admitted to an exercise program (45-minute walking sessions at 60–80% of maximum heart rate) every day except weekends for four weeks (total 20 exercise sessions). Insulin resistance was evaluated by HOMA model. Plasma glucose, insulin and leptin levels were determined at baseline and at the end of the first, seventh, and twentieth exercise session. Results: Baseline and at the end of the first, seventh, and twentieth exercise session plasma leptin levels were 59.1 ± 20.1, 58.5 ± 21.0, 53.4 ± 21.9, and 51.2 ± 20.5 ng/ml and HOMA-r were 2.75 ± 1.47, 1.77 ± 0.71, 1.73 ± 0.89, 1.62 ± 0.70, respectively. Compared to baseline, at the end of the seventh (p=0.021) and twentieth exercise session (p=0.003), plasma leptin levels were significantly low. Plasma leptin level did not change significantly at the end of the first exercise session (p>0.05). At the end of the first exercise session (p=0.005), end of the seventh (p=0.003) and twentieth exercise session (p=0.007) HOMA-r was lower than baseline. There was no correlation between weight loss during exercise period and the change of leptin, and HOMA-r. Fasting plasma glucose, insulin and leptin levels were determined at baseline and at the end of the first, seventh, and twentieth exercise session. Conclusion: Our study suggests that acute exercise decreases insulin resistance at the first exercise session with no effect on leptin levels. Significant leptin decrement was evident at the first week and lasted during the entire four weeks exercise session.

Effects of Propylthiouracil Treatment on Antioxidant Activities in Blood of Toxic Multinodular Goiter Patients

Erythrocyte, serum and plasma antioxidant activities and the effects of propylthiouracil (PTU) treatment on these activities were studied in patients with toxic multinodular goiter. The activities of the erythrocyte antioxidant enzymes (glucose-6-phosphate dehydrogenase, catalase, Cu/Zn-superoxide dismutase, selenium (Se)-dependent glutathione peroxidase and glutathione reductase) and the levels of erythrocyte Se, serum ceruloplasmin and plasma malondialdehyde were significantly higher while serum vitamin E, plasma vitamin C and plasma Se were lower in hyperthyroid patients. PTU treatment, not for 1 but for 3 months caused a partial reversal of antioxidant activities to euthyroid levels. It is suggested that alterations in blood antioxidant activities following PTU treatment might be due to the antioxidant and/or antithyroid effect of this drug.