Oguz Ozcelik

Homocysteine-induced enhancement of spontaneous contractions of myometrium isolated from pregnant women

Background.  Although many associations have been demonstrated between hyperhomocysteinemia and pregnancy complications, such as spontaneous abortion, preterm labor, preeclampsia and low birthweight, it is still not clear whether hyperhomocysteinemia is the cause or the consequence of these pregnancy complications. The aim of this study was to investigate the effects of homocysteine on the spontaneous contractility of isolated pregnant human myometrium.

Nitric oxide levels in response to the patients with different stage of diabetes

The association between hyperglycaemia and serum nitric oxide (NO) levels has not yet been fully clarified. Thus, it was aimed to evaluate the concentration of NO metabolites (nitrate, nitrite) in diabetic patients and to find the relationship between hyperglycaemia and serum NO levels in diabetic and prediabetic patients, and control groups. In this study, 100 subjects were divided into 3 groups: healthy control (n=20), prediabetic (n=40) and diabetic (n=40). Glycemic control was assessed using glycated hemoglobin (HbA1c). Nitrate and nitrite levels were measured using the Griess reagent. NO was obtained from the sum of nitrates and nitrites. The serum NO level was higher in diabetic (53.4±2.0 μM) and prediabetic patients (51.6±1.6 μM) as compared to that in the control (45.6±1.2 μM), (p<0.05). The NO level was not significantly different in diabetic and prediabetic patients. Higher levels of serum glucose, insulin and HOMA-IR may be responsible for the activation of endothelial cells to increase NO levels. This study supports the role of insulin resistance in increased NO levels in both diabetic and prediabetic patients.

Effects of a Weight-Reduction Program with Orlistat on Serum Leptin Levels in Obese Women: A 12-Week, Randomized, Placebo-Controlled Study

BACKGROUND Leptin, which has been identified as an antiobesity hormone, regulates body weight by controlling food intake and energy expenditure via the hypothalamic-pituitary-gonadal axis. It appears that leptin may be an important factor in obesity management. Orlistat, a pancreatic lipase inhibitor, could reduce fat absorption and promote weight loss due to leptin metabolism. OBJECTIVE The purpose of this study was to investigate the effects of orlistat therapy on serum leptin levels. METHODS Obese women (body mass index [BMI], 30 kg/m(2)) aged 18 to 50 years were randomly assigned to receive 12 weeks of oral treatment with diet-orlistat (120 mg TID) (DO group) or diet-placebo (DP group). During the treatment period, patients were asked to eat a balanced diet of -1200 to 1600 kcal/d. Body composition was determined by bioelectrical impedance. Serum leptin levels were measured using radioimmunoassay at baseline and at study end. RESULTS A total of 24 patients entered the study; 14 patients (mean [SE] BMI, 37.7 [1.1] kg/m(2)) received orlistat and 10 patients (mean [SE] BMI, 39.4 [1.3] kg/m(2)) received placebo. Compared with baseline, mean percentages of loss of body weight and fat mass after 12 weeks of treatment were significant in the DO group (9.1% and 14.8%, respectively; both P = 0.001) and in the DP group (9.5% and 17.6%; both P = 0.005). The between-group differences were not statistically significant. Mean (SE) serum leptin levels also decreased significantly after treatment in the DO group (16.2 [1.2] vs 9.0 [1.0] ng/mL; P = 0.001) and in the DP group (19.3 [2.1] vs 9.7 [1.4] ng/mL; P = 0.005). The between-group difference was not statistically significant. CONCLUSIONS In this study of obese women, orlistat treatment was associated with a similar decrease in body weight, fat mass, and serum leptin levels as placebo over a 12-week period. In this regard, short-term orlistat therapy may not provide an additional effect on serum leptin levels, and reduction in leptin levels were closely related to the decrease in fat mass.

Evaluating the Levels of Nesfatin-1 and Ghrelin Hormones in Patients with Moderate and Severe Major Depressive Disorders

Objective The goal of this study was to evaluate the importance of nesfatin-1, acylated and des-acylated ghrelin, which are known as energy regulatory hormones, in patients with moderate and severe major depression disorders (MDD). Methods Thirty patients with a moderate degree of MDD and, 30 with a severe degree of MDD were used as participants in this study. Thirty subjects without depression were enrolled as a control group. The Hamilton Depression Rating Scale was used to classify the patients with MDD. Blood samples were taken after overnight fasting. The plasma nesfatin-1, acylated ghrelin and des-acylated ghrelin levels were measured using a commercially available enzyme-linked immunosorbent assay kit. Results The nesfatin-1, the acylated ghrelin and the des-acylated ghrelin levels were found to be significantly higher in severe MDD (3.92±0.4 ng/mL; 88.56±4.1 pg/mL; 962.76±67 pg/mL) as compared to moderate MDD (2.91±0.5 ng/mL; 77.63±4.19 pg/mL; 631.16±35 pg/mL), or the control (1.01±0.3 ng/mL; 58.60±9.00 pg/mL; 543.13±62 pg/mL), respectively. Conclusion Although nesfatin-1 and ghrelin are known as adversely affecting the hormones involving the regulation of appetite and food intake, they all increase in depressive patients and are even associated with the severity of the disease. In clinical medicine, the evaluation of the role of nesfatin-1 and ghrelin in endocrine and neu-roendocrine regulation of major metabolic functions is an important key mechanism in solving numerous diseases associated with endocrine and neuroendocrine disturbance. Increased levels of nesfatin-1 and ghrelin may also be important criteria in describing the prognoses of the patients and the effectiveness of the treatments.

Variations in leptin, nesfatin-1 and irisin levels induced by aerobic exercise in young trained and untrained male subjects

The aims of this study were to investigate the impacts of acute aerobic exercise on circulating levels of hormones associated with energy metabolism, namely leptin, nesfatin-1 and irisin, in trained and untrained male subjects and to determine whether the timing of the exercise (i.e. morning or night) amplified these impacts. Thirty trained (19.2±0.7 years) and 30 untrained (19.5±0.6 years) male subjects performed two aerobic running exercises (3 days between tests) to 64-76% of the subjects’ maximal heart rate for about 30 min. Pre- and post-exercise venous blood samples were taken and analysed for leptin, nesfatin-1 and irisin using enzyme-linked immunosorbent assay (ELISA). Paired samples and independent samples t-tests were used to analyse data. Irisin levels increased in all the subjects (p<0.001). In both groups, nesfatin-1 levels increased significantly after the night-time exercise (p<0.05). Importantly, leptin and nesfatin-1 levels varied among the trained and untrained groups: Both leptin and nesfatin-1 levels increased in 4 (13%) and 12 (40%) subjects, respectively, after the morning exercises, and they increased in 9 (30%) and 10 (33%) subjects, respectively, after the night-time exercise. They decreased in 5 (16%) and 7 (23%) subjects, respectively, after the morning exercise and in 6 (20%) and 3 (10%) subjects, respectively, after the night-time exercise. Exercise may result in increased energy consumption by altering irisin levels. However, due to variations among individuals, increasing leptin and nesfatin-1 levels by reducing food intake may not be applicable.

Comparative determination of ventilatory efficiency from constant load and incremental exercise testing

The analysis of the relationships between minute ventilation (VE) to CO2 output (VCO2), referred to as ventilatory efficiency, in response to incremental exercise testing, is considered a useful index for assessing the presence and severity of cardiopulmonary and metabolic diseases. The effects of constant load exercise testing performed at work intensity associated with anaerobic threshold (AT) and respiratory compensation points (RCP), on the accurate measurements of ventilatory efficiency are not well known. The aim of this present study was to investigate the reliability of the VE/VCO2 ratio obtained from constant load exercise tests performed with two important metabolic rates (at the AT and RCP) and compare it to that of those of incremental exercise tests. A total of 20 young male (20.8±0.4 yr) subjects initially performed an incremental exercise test and then two constant load exercise tests, on different days. Respiratory and pulmonary gas exchange variables were used to estimate AT and RCP. A paired t-test was used to analyse data. AT and RCP (average) occurred the at 60% and at 71% of peak O2 uptake, respectively. The lowest VE/VCO2 ratio recorded within the first 2 minutes of constant load exercise tests with a work load of AT (26.4±0.3) and RCP (26.7±0.5) was not statistically different from the lowest ratio obtained from the incremental exercise tests (26.0±0.7). In the constant load exercise test, despite the different metabolic rates, the increase in ventilation corresponded closely with the increase in CO2 production, reflecting an optimal ventilation and perfusion ratio. Clinicians should consider the constant load exercise test work load associated with AT and RCP as it provides a meaningful lowest value for ventilatory efficiency.

Beneficial effects of training at the anaerobic threshold in addition to pharmacotherapy on weight loss, body composition, and exercise performance in women with obesity

Objective The aim of this study was to determine and compare the effects of weight loss achieved through orlistat therapy alone or a combination of orlistat and an aerobic exercise training program on aerobic fitness and body composition in obese females. Methods Twenty-eight obese patients were randomly assigned to receive 12-week treatment with hypocaloric diet–orlistat or diet–orlistat–exercise. Each participant performed an incremental ramp exercise test every 4 weeks to measure aerobic fitness. Fourteen participants performed continuous exercise (approximately 45 minutes per session) at a work rate corresponding to the anaerobic threshold three times per week. Results A decrease in the fat mass to body weight ratio of 3.8% (P=0.006) was observed at the end of the 12 weeks in the orlistat group, while a decrease of 9.5% (P=0.001) was seen in the orlistat–exercise group. Maximal exercise capacity increased by 46.5% in the orlistat–exercise group and by 19.5% in the orlistat group. Conclusion While orlistat therapy resulted in an improvement in body composition and aerobic fitness at the end of the 12-week period, its combination with exercise training provided improvements in the same parameters within the first 4 weeks of the study. These additional beneficial effects of combining aerobic exercise with orlistat therapy are important with regards to obesity-associated risk factors.