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    Effect of Surgical Weight Loss on Free Radical and Antioxidant Balance: a Preliminary Report
    (F D-Communications Inc, 2002) Kısakol, Gürcan; Güney, Engin; Bayraktar, Fırat; Yilmaz, Candeğer; Kabalak, Taylan; Özmen, Dilek
    Background: This study observes the effect of surgical weight loss on free radical and antioxidant vitamin balance. Patients and Methods: 22 consecutive morbidly obese patients undergoing vertical banded gastroplasty (VBG) were chosen for the study. Postoperative studies were done at 12 and 24 weeks. Plasma antioxidant and vitamin determinations were performed by HPLC method. Results: Subjects lost a significant amount of weight (P<0.01). Compared to preoperative measurements, postoperative measurements of plasma betacarotene were not statististically different both at 12 and 24 weeks (13.86&PLUSMN;1.26 μg/dl, 12.35&PLUSMN;1.2, P=0.44; 14.33&PLUSMN;2.03, P=0.77; preoperatively, 12 and 24 weeks respectively). Alpha-tocopherol increased slightly at the 12th week; the difference was not significant (8.50&PLUSMN;0.77; 9.56&PLUSMN;0.82, P=0.37; preoperatively and 12th week respectively). The levels of alpha-tocopherol rose at 24th week significantly (10.89&PLUSMN;0.55, P=0.028). The indicator of lipid peroxidation (malondialdehyde) decreased with weight loss (1.505&PLUSMN;0.11 μmol/L preoperatively; 0.75&PLUSMN;0.062 at 12th week, P=0.01; 0.712&PLUSMN;0.05 at 24th week, P<0.01). Conclusion: Our data show that free radical generation falls markedly in association with weight loss after VBG. Surgical weight loss leads to significant decrease in oxidant production and also leads to increase in some antioxidant vitamins. The demonstration of decreased free radical generation and correction of balance between free radicals and antioxidant vitamins has important implications for oxidative mechanisms underlying obesity-associated disorders.
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    Effect of Weight Loss on Bone Metabolism: Comparison of Vertical Banded Gastroplasty and Medical Intervention
    (Springer, 2003) Güney, Engin; Kısakol, Gürcan; Özgen, Gökhan; Yılmaz, Candeğer; Yılmaz, Rasih; Kabalak, Taylan
    Background: We studied the effects of weight loss on bone metabolism. Methods: 16 consecutive surgically-treated (14 female, 2 male) morbidly obese patients and 65 obese (53 male, 12 female) medically-treated patients were enrolled in an observational study. Surgical treatment for morbidly obese patients was vertical banded gastroplasty (VBG). Studies were performed prior to and 12 months after the start of treatment. Bone mineral density (BMD), bone turnover markers, sex steroids, calcium excretion and parathyroid hormone measurements were done at each visit. Results: Weight loss was more prominent with surgical than with medical treatments. Bone loss was also pronounced in the surgical treatment group, and occurred at the hip level only (P<0.05). Compared to previously reported studies, where the effects of malabsorptive treatments for obesity on bone metabolism were studied, calcium excretion and parathyroid hormone levels did not change after VBG or medical therapy. For both groups, bone markers indicated an increased bone turnover, evidenced by increased urinary excretion of deoxypyridinoline and serum levels of osteocalcin (P<0.05). Sex steroid measurements revealed a decrease in estradiol levels in the surgical treatment group, but not in medical treatment group. This finding was thought to be secondary to less weight loss in the medical group. Conclusion: Our data indicate that weight loss causes bone loss. The bone loss is independent of the method of weight reduction. However, the mechanism of the bone loss is not clear. It may be explained partly by reduced estradiol levels in female patients. Because the mechanisms of bone disease after weight loss remain unclear, it is difficult to determine the most effective treatment. It is important to detect osteopenia early, before fractures occur. Measuring BMD appears to be the only reliable method for screening.
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    Effects of bisphosphonates on lipid metabolism
    (MAGHIRA & MAAS PUBLICATIONS, 2008) Guney, Engin; Kisakol, Gurcan; Ozgen, A. Gokhan; Yilmaz, Candeger; Kabalak, Taylan
    OBJECTIVES: Bisphosphonates are widely used for the treatment of metabolic bone disorders and their effects on lipid metabolism have also been investigated. Some studies reported that bisphosphonates have beneficial effects on serum cholesterol levels. In this study we aimed to assess the effects of bisphosphonates on lipid levels in hyperlipidemic patients who received bisphosphonates because of osteoporosis. METHODS: 49 female patients (age: 54.2 +/- 7.2 years) with diagnosis of osteoporosis and hyperlipidemia were enrolled. Patients received alendronate 10 mg/day and they were followed up for 6 months. Pretreatment total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, apolipoprotein A1 and apolipoprotein B levels were measured and compared with post-treatment levels. RESULTS: Pretreatment and post-treatment levels of total cholesterol were 255.2 +/- 34.3; 233.02 +/- 37.0 mg/dL, triglyceride levels were 153.0 +/- 57.3; 129.1 +/- 54.4 mg/dL, and LDL levels were 170.7 +/- 30.5; 160.0 +/- 34.2 mg/dL, respectively. Reductions in total cholesterol, triglyceride and LDL-cholesterol levels were statistically significant; whereas differences in HDL-cholesterol, apolipoprotein-A1 and apolipoprotein-B levels were not significant. CONCLUSIONS: Data from our study suggest that alendronate therapy may have beneficial effects on lipid metabolism. Thus, when hyperlipidemia is detected in patients receiving bisphosphonates, it is considered reasonable to follow the patient for a while before initiating antihyperlipidemic agent to prevent unnecessary use of drugs.
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    Effects of İnsulin and Sulphonylureas on İnsulin-Like Growth Factor-I Levels in Streptozotocin-İnduced Diabetic Rats
    (Maghira & Maas Publications, 2002) Güney, Engin; Kısakol, Gürcan; Öge, Ayşin; Yılmaz, Candeğer; Kabalak, Taylan
    OBJECTIVE: Diabetes Mellitus is associated with decreased insulin-like growth factor-I (IGF-I) levels and also, poor growth in diabetes is related with low circulating levels of IGF-I. Insulin acts via an increase of IGF-I synthesis on growth. We studied the effects of insulin and sulphonylureas on serum IGF-I levels and aimed to evaluate the restoration of IGF-I in different therapeutic strategies. DESIGN AND SETTING: Thirty male rats were used in the study and diabetes was induced by a single intraperitoneal injection of streptozotocin (35 mg/kg body weight). After confirmation of hyperglycemia, rats were divided into three groups. The first group was treated with insulin, and second group with glimepiride, third group was not treated (control group). IGF-I levels were measured at basal, after streptozotocin and at the end of the treatment period. RESULTS: Serum IGF-I levels were found to decrease from 577.2 ng/ml to 253.0 ng/ml after streptozotocin (p<0.005). After 1 month, IGF-1 levels were found 524.0 ng/ml in insulin group, 449.3 ng/ml in sulphonylurea group, and 313.1 ng/ml in control group. The increase in IGF-I was statistically significant in insulin group (p<0.005), and in sulphonylurea group (p<0.05), but it was not significant in control group (p>0.05). CONCLUSIONS: Serum IGF-I levels decrease in diabetes and insulin treatment restores IGF-I depletion significantly. And although less effective, treatment with glimepiride restores IGF-I levels significantly.