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Featured researches published by Miyase Bayraktar.


Menopause | 2008

Soy isoflavones in the management of postmenopausal osteoporosis.

Aysegul Atmaca; Michael Kleerekoper; Miyase Bayraktar; Omer Kucuk

This is a review article designed to address the effects of soy isoflavones on bone metabolism in postmenopausal women and their place in the prevention and treatment of postmenopausal osteoporosis. Soy isoflavones are natural products that could be used as an alternative to menopausal hormone therapy because they are structurally and functionally related to 17&bgr;-estradiol. In vitro and animal studies have shown that they act in multiple ways to exert their bone-supporting effects. They act on both osteoblasts and osteoclasts through genomic and nongenomic pathways. Epidemiological studies and clinical trials suggest that soy isoflavones have beneficial effects on bone mineral density, bone turnover markers, and bone mechanical strength in postmenopausal women. However, there are conflicting results related to differences in study design, estrogen status of the body, metabolism of isoflavones among individuals, and other dietary factors. The long-term safety of soy isoflavone supplements remains to be demonstrated.


The American Journal of the Medical Sciences | 2008

Molecular Diagnosis and Clinical Characterization of Pseudohypoparathyroidism Type-Ib in a Patient With Mild Albright’s Hereditary Osteodystrophy-Like Features, Epileptic Seizures, and Defective Renal Handling of Uric Acid

Ugur Unluturk; Ayla Harmanci; Miyase Bayraktar; Melih O. Babaoglu; Umit Yasar; Kubilay Varli; Murat Bastepe

We describe a patient who presented with epileptic seizures unresponsive to anticonvulsive treatment. Laboratory investigations demonstrated epileptiform seizure activity in the brain but also revealed severe hypocalcemia, hyperphosphatemia, and elevated serum parathyroid hormone. In addition, the patient showed a reduced serum level of 25-[OH]-vitamin D. The diagnosis of pseudohypoparathyroidism type-Ib (PHP-Ib) was made based on these clinical findings and upon identification of a 3-kb deletion within the STX16 locus, a genetic defect frequently associated with autosomal dominant PHP-Ib. This mutation was also present in the patients unaffected mother and her affected sister. Despite the molecular diagnosis of PHP-Ib, which is characterized by parathyroid hormone resistance in the absence of Albrights hereditary osteodystrophy (AHO), the patient had a round face, slightly short stature, and short fourth metacarpals, which were consistent with mild AHO. The patient and her affected sister, who lacked AHO-like features, showed reduced serum levels of uric acid and increased fractional excretion of uric acid, a finding that was reported only once previously for PHP-Ib. Unlike the previous report, the fractional uric acid excretion and serum uric acid levels returned to normal in our patient and her sister after 3 months of treatment period. These findings underscore several important points with respect to the pathogenesis and clinical presentation of PHP-Ib. Furthermore, the findings in the index case present interesting novel aspects, including a previously undescribed coexistence of the 3-kb STX16 deletion and AHO-like features and a clinical course complicated by concomitant 25-[OH]-vitamin D deficiency, which may have resulted, at least partly, from long-term use of antiepileptic drugs.


Journal of Clinical Gastroenterology | 1997

Liver tests in hyperthyroidism : Effect of antithyroid therapy

Alper Gürlek; Veli Çobankara; Miyase Bayraktar

Changes in liver biochemical test results have been described in hyperthyroid patients before and after antithyroid therapy. In the present study, we analyzed liver tests at diagnosis and after 6 weeks of treatment with propylthiouracil (PTU) in 43 patients with hyperthyroidism. At diagnosis, 60.5% of the patients had at least one liver abnormality. Elevations of alkaline phosphatase, alanine and aspartate aminotransferase, and gamma-glutamyl transpeptidase levels were observed in 19 (44.2%), 10 (23.3%), six (14%), and six (14%) of the patients, respectively. At the end of the 6-week treatment with PTU, elevations in liver test values, possibly induced by PTU, were found in seven (16.3%) patients. Age, sex, type of goiter (either diffuse or multinodular), and presence or absence of abnormal liver biochemical tests at diagnosis were not significant in determining the possibility of PTU-induced elevations in liver tests. These data suggest that liver test abnormalities are frequently found at the time of diagnosis of hyperthyroidism. However, the presence or absence of these abnormalities does not predict elevations in liver test results, which are possibly induced by PTU during therapy.


Advances in Therapy | 2007

Influence of type 2 diabetes mellitus on bone mineral density response to bisphosphonates in late postmenopausal osteoporosis

Selcuk Dagdelen; Didem Sener; Miyase Bayraktar

Bisphosphonates are effective agents for postmenopausal osteoporosis, but their efficacy in patients with type 2 diabetes mellitus (DM) is not known. The investigators evaluated bone mineral density (BMD) response to alendronate in women with concurrent late postmenopausal osteoporosis and type 2 DM. In a retrospective, matched case-control study, 26 late postmenopausal osteoporotic women with type 2 DM (age, 67.6±7.3 y; type 2 DM duration, 12.8±6.8 y; duration of menopause, 10.9±7.4 y; time on alendronate: 4.8±2.3 y; body mass index [BMI], 31.4±6.3 kg/m2) were matched with 26 controls according to age, BMI, duration of menopause, and alendronate treatment received. All subjects were given alendronate 10 mg/d or 70 mg/wk, along with sufficient vitamin D (≥400 IU) and calcium (≥1 g/d) intake, for 4.8 y. Response to alendronate therapy was determined by assessment of mean percent change in BMD of total hip, femoral neck, forearm, and lateral spine. The presence of type 2 DM resulted in no difference in spinal BMD response to alendronate therapy. In contrast, BMD in the total hip (mean percent change in BMD, −5.6% vs +1.4%;P=.096), femoral neck (−8.1 % vs +1.1 %;P=.015), and forearm (−3.6% vs +12.7%;P=.013) fell progressively from baseline in subjects with type 2 DM who were taking alendronate for 4.8 y, compared with controls. Elderly, postmenopausal, osteoporotic obese women with type 2 DM are resistant to long-term bisphosphonates, especially in regions of the hip, femoral neck, and forearm compared with the spine. The efficacy of bone resorption inhibitors in patients with type 2 DM, especially in comparison with anabolic agents, should be considered in additional studies.


Endocrine | 2009

Circulating adiponectin represents a biomarker of the association between adiposity and bone mineral density

Kemal Agbaht; Alper Gürlek; Jale Karakaya; Miyase Bayraktar

An association exists between adiposity, insulin resistance, and osteoporosis; however, the mechanism of this relationship remains enigmatic. We aimed to determine whether the insulin resistance index (HOMA-IR), serum adiponectin, or leptin levels are associated with bone mineral density (BMD). A cross-sectional, observational study was designed. Eighty-four postmenopausal ambulant women [52.5 (50.0–58.0) years; body mass index (BMI): 29.4 (25.9–33.8) kg/m2] referred for osteoporosis screening were enrolled. Anthropometric measures, fasting serum adiponectin and leptin levels, and the HOMA-IR were determined. The relationships between these variables and lumbar, hip, and forearm BMD measured by dual-energy X-ray absorptiometry (DXA) were analyzed. Considering all 84 participants, the HOMA-IR index was 1.82 (1.17–2.86), serum adiponectin was 13.25 (10.49–16.88) μg/ml, and serum leptin was 19.26 (14.94–24.90) ng/ml. BMI, waist circumference, and leptin positively correlated with hip and lumbar BMD, whereas adiponectin negatively correlated. Multivariate analysis confirmed an inverse relation between serum adiponectin level and femoral neck and lumbar BMD measurements. In total hip and forearm areas, there was no independent association of adipocytokines with BMD measurements. Instead, waist circumference was independently associated with BMD measurements. In conclusion, adiponectin may represent a biomarker in the relationship between visceral fat mass and BMD. However, this association is probably confounded by the specific body composition parameters (i.e., waist circumference, BMI) in postmenopausal women.


Nuclear Medicine Communications | 2012

Comparison of 800 and 3700 MBq iodine-131 for the postoperative ablation of thyroid remnant in patients with low-risk differentiated thyroid cancer.

Meltem Caglar; Fani Bozkurt; Ceren Kapulu Akca; Sezen Elhan Vargol; Miyase Bayraktar; Omer Ugur; Ergun Karaağaoğlu

IntroductionThe initial treatment of differentiated thyroid cancer is thyroidectomy, followed by remnant ablation with iodine-131 (I-131) in some patients. However, controversy exists concerning the appropriate radioiodine dose. The aim of the study is to compare the success rate of low and high activities of I-131 for postoperative remnant ablation. Patients and methodsA total of 108 nonmetastatic low-risk patients (mean age: 46, 85% women) with papillary and follicular carcinoma had I-131 ablation for the postoperative thyroid remnant. Fifty-three patients received a low dose (L) (800 MBq) and 55 patients received a high dose (H) (3700 MBq) of I-131. After total thyroidectomy, thyroid bed I-131 uptake (RAIU) and neck ultrasonography (USG) were performed to determine the remnant volume and the iodine avidity, which were used to calculate the dose delivered to the remnant tissue. The success rate of I-131 ablation was assessed with four different criteria based on serum thyroglobulin (Tg) and USG with and without the utilization of I-131 diagnostic whole-body scintigraphy (DxWBS). Ablation was considered to be successful if patients fulfilled all of the following criteria. (a) Strict criteria based on three tests: (i) USG negative, (ii) no tracer uptake or less than twice the background activity in the thyroid bed on DxWBS and/or up to 0.2% RAIU, and (iii) Tg<0.2 ng/ml; (b) lax criteria based on three tests: (i) USG negative, (ii) no tracer uptake or less than twice the background activity in the thyroid bed on DxWBS and/or ⩽0.2% RAIU, and (iii) Tg<2 ng/ml; (c) strict criteria based on two tests: (i) USG negative and (ii) Tg <0.2 ng/ml; (d) lax criteria based on two test: (i) USG negative and (ii) Tg <2 ng/ml. ResultsWhen three tests were used to define successful ablation, in group L, 32 out of 53 (60%) and 43 out of 53 (81%) patients were successfully treated versus 35 out of 55 (64%) and 42 out of 55 (76%) for group H on the basis of strict and lax criteria, respectively (P=NS). The differences were not statistically significant between the two groups when only two tests were used to define ablation success (62 vs. 69% with strict and 89 vs. 87% with lax criteria, respectively). ConclusionOur findings suggest that remnant thyroid tissue in patients with low-risk, well-differentiated thyroid cancer after total thyroidectomy can be ablated with 800 MBq of I-131. The success rate is not different from that obtained with 3700 MBq I-131.


Clinical Endocrinology | 2013

Oral contraceptive plus antiandrogen therapy and cardiometabolic risk in polycystic ovary syndrome

Ayla Harmanci; Nese Cinar; Miyase Bayraktar; Bulent O. Yildiz

Oral contraceptives alone or in combination with antiandrogens are commonly used in the treatment for polycystic ovary syndrome (PCOS). We aimed to determine the effects of ethinyl estradiol/drospirenone (EE‐DRSP) plus spironolactone therapy on inflammation and cardiometabolic risk in PCOS.


Clinical Endocrinology | 2010

Dynamics of Nampt/visfatin and high molecular weight adiponectin in response to oral glucose load in obese and lean women

Ugur Unluturk; Ayla Harmanci; Bulent O. Yildiz; Miyase Bayraktar

Background  High molecular weight adiponectin (HMWA) is the active circulating form of adiponectin. Nampt/visfatin is the enzyme secreted from adipocytes in an active form and is one of the putative regulators of insulin secretion.


Clinical Endocrinology | 2013

Ethinyl estradiol-drospirenone vs ethinyl estradiol-drospirenone plus metformin in the treatment of lean women with polycystic ovary syndrome.

Nese Cinar; Ayla Harmanci; Miyase Bayraktar; Bulent O. Yildiz

Oral contraceptive use might be associated with cardiometabolic risk in PCOS. We aimed to compare the effects of ethinyl estradiol–drospirenone (EE/DRSP) alone vs EE/DRSP plus metformin on clinical and cardiometabolic parameters in PCOS.


Medical Science Monitor | 2013

Serum resistin and high sensitive CRP levels in patients with subclinical hypothyroidism before and after L-thyroxine therapy

Duygu Yazgan Aksoy; Nese Cinar; Ayla Harmanci; Jale Karakaya; Bulent O. Yildiz; Aydan Usman; Miyase Bayraktar

Background Subclinical hypothyroidism (SH) is defined by increased thyrotropin (TSH) and normal free thyroxine (fT4) and free triiodothyronine (fT3) levels. Resistin is secreted from adipose tissue and is reported to be associated with insulin resistance and/or inflammation. High sensitive CRP (hs-CRP) is a reliable marker of inflammation. Data related to levels of resistin and hs-CRP in SH and the effect of L-thyroxine treatment on those is limited. We aimed to determine the levels of resistin and hs-CRP in women with SH, and potential effects of L-thyroxine therapy on those levels. Material/Methods Thirty-six patients with SH and 27 age- and BMI-matched healthy control women were included. Waist circumference (Wc), waist-to-hip ratio (WHR), resting energy expenditure (REE), fat mass (FM) and lean mass (LM), TSH, free T4 (fT4), free T3 (fT3), total cholesterol (TC), triglycerides (TG), and HDL- and LDL-cholesterol were determined in all participants. Patients received L-thyroxine treatment for 6 months, after which all measurements were repeated. Resistin and hs-CRP levels were studied from frozen samples after the completion of the study. Results The 2 groups had similar values for Wc, WHR, FM, LM, TC, TG, HDL-C, LDL-C, resistin, and hs-CRP at the beginning. fT4 were higher, whereas TSH was lower in the control group. Resistin and hs-CRP levels did not change after treatment. hs-CRP correlated with BMI and FM before and after treatment. Conclusions Our results suggest that achievement of euthyroid status by replacement therapy did not change resistin or hs-CRP levels in women with SH. hs-CRP correlated with parameters of obesity, which emphasizes the role of body weight in inflammation.

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