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Dive into the research topics where Ayhan Abaci is active.

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Featured researches published by Ayhan Abaci.


Diabetes Research and Clinical Practice | 2009

Vaspin and its correlation with insulin sensitivity indices in obese children

Selami Suleymanoglu; Emre Tascilar; Ozgur Pirgon; Serkan Tapan; Cihan Meral; Ayhan Abaci

AIM The aim of this study was to assess the vaspin and adiponectin concentrations on markers of insulin sensitivity and obesity in pubertal obese children and adolescents. MATERIAL AND METHODS Plasma vaspin and adiponectin level and its relationships with body mass index standard deviation score (BMI-SDS), insulin sensitivity and lipids were analyzed in 33 pubertal obese children (19 girls and 14 boys) and 36 healthy control children (18 girls and 18 boys) aged 11-16 years. Insulin resistance was evaluated by homeostasis model assessment (HOMA-IR) and fasting glucose-to-insulin ratio (FGIR). Plasma vaspin and adiponectin concentrations were determined with radioimmunoassay. RESULTS Mean vaspin levels were found significantly higher and inversely, adiponectin levels were found significantly lower in obese pubertal group than control subjects. Vaspin levels were positively correlated with BMI-SDS, triglycerides, fasting insulin and HOMA-IR and negatively correlated with adiponectin levels and FGIR. Adiponectin levels were positively correlated with high density lipoprotein-chloesterol, FGIR and negatively correlated with vaspin, BMI-SDS, fasting insulin and HOMA-IR. CONCLUSION We found higher vaspin and lower adiponectin levels in obese children and these adipokines were significantly correlated with insulin sensitivity indices in this age.


Journal of Diabetes and Its Complications | 2008

Hepatic glycogenosis: a rare cause of hepatomegaly in Type 1 diabetes mellitus

Ayhan Abaci; Özlem Bekem; Tolga Ünüvar; Erdener Özer; Ece Böber; Nur Arslan; Yesim Ozturk; Atilla Büyükgebiz

Hepatomegaly, with or without abnormal liver function tests, was a common feature of both pediatric and adult patients with diabetes mellitus. We are reporting a case of a 16-year-old diabetic boy in whom we found hepatomegaly, mildly elevated transaminases and elevated serum lipids never noticed before. Abdominal ultrasound confirmed hepatomegaly; liver biopsy pointed out a picture compatible with glycogenosis. The patients abnormal liver function tests, elevated serum lipids and hepatomegaly decreased over a period of 4 weeks with tight metabolic control. This situation was due to overinsulinization because the patient assumed an excessive quantity of food and therefore took an excessive quantity of insulin. In conclusion, hepatomegaly may be seen in diabetic patients due to hepatic glycogen accumulation as a result of excessive food and insulin consumption. In hepatic glycogenosis, the pathological findings improve in 4 weeks when good metabolic control is provided. Therefore, the other reasons must be investigated when hepatomegaly persists for a longer period.


Pediatric Diabetes | 2013

The relation of serum nesfatin-1 level with metabolic and clinical parameters in obese and healthy children

Ayhan Abaci; Gönül Çatlı; Ahmet Anık; Tuncay Kume; Ece Böber

Nesfatin‐1, a recently discovered anorexigenic neuropeptide, is expressed in several tissues including pancreatic islet cells and central nervous system. This peptide seems to play an important role in hypothalamic pathways regulating food intake and energy homeostasis.


Pediatric Diabetes | 2011

P300 auditory event‐related potentials in children with obesity: is childhood obesity related to impairment in cognitive functions?

Mehmet Emre Taşçılar; Doga Turkkahraman; Oguzhan Oz; Mehmet Yücel; Mustafa Taskesen; İbrahim Eker; Ayhan Abaci; Rusen Dundaroz; Ümit Hıdır Ulaş

Tascilar ME, Turkkahraman D, Oz O, Yucel M, Taskesen M, Eker I, Abaci A, Dundaroz R, Ulas UH. P300 auditory event‐related potentials in children with obesity: is childhood obesity related to impairment in cognitive functions?


Journal of Pediatric Endocrinology and Metabolism | 2015

Maturity-onset diabetes of the young (MODY): an update

Ahmet Anık; Gönül Çatlı; Ayhan Abaci; Ece Böber

Abstract Maturity-onset diabetes of the young (MODY) is a group of monogenic disorders characterized by autosomal dominantly inherited non-insulin dependent form of diabetes classically presenting in adolescence or young adults before the age of 25 years. MODY is a rare cause of diabetes (1% of all cases) and is frequently misdiagnosed as Type 1 diabetes (T1DM) or Type 2 diabetes (T2DM). A precise molecular diagnosis is essential because it leads to optimal treatment of the patients and allows early diagnosis for their asymptomatic family members. Mutations in the glucokinase (GCK) (MODY 2) and hepatocyte nuclear factor (HNF)1A/4A (MODY 3 and MODY 1) genes are the most common causes of MODY. GCK mutations cause a mild, asymptomatic, and stable fasting hyperglycemia usually requiring no specific treatment. However, mutations in the HNF1A and HNF4A cause a progressive pancreatic β-cell dysfunction and hyperglycemia that can result in microvascular complications. Sulfonylureas are effective in these patients by acting on adenosine triphosphate (ATP)-sensitive potassium channels, although insulin therapy may be required later in life. Mutations in the HNF1B (MODY 5) is associated with pancreatic agenesis, renal abnormalities, genital tract malformations, and liver dysfunction. Compared to MODY 1, 2, 3, and 5, the remaining subtypes of MODY have a much lower prevalence. In this review, we summarize the main clinical and laboratory characteristics of the common and rarer causes of MODY.


International Journal of Obesity | 2009

Threshold value of subepicardial adipose tissue to detect insulin resistance in obese children

Ayhan Abaci; Mehmet Emre Taşçılar; T Sarıtas; Y Yozgat; Ediz Yesilkaya; A Kılıc; V Okutan; M K Lenk

Aim:Until now, the association between subepicardial adipose tissue (SAT), insulin resistance and intima–media thickness (IMT) has not been evaluated in obese children. In this study, we evaluated whether echocardiographic SAT is related to insulin resistance and IMT in obese children.Subjects and Methods:A total of 46 obese subjects (10.2±2.5 years of age, 25 male patients) and 30 age- and gender-matched lean subjects (10.8±3.1 years of age, 13 male patients) were included in this study. The criterion for diagnosing obesity was defined as the body mass index (BMI) being over 97% percentile of the same gender and age. Serum triglyceride (TG), low- and high-density lipoprotein, cholesterol, glucose and insulin levels were measured during the fasting state. Each subject underwent a transthoracic echocardiogram and the SAT thickness was measured during end-diastole from the parasternal long-axis views.Results:The obese subjects had significantly higher SAT thickness and IMT values compared with the subjects in the control group (5.7±1.4 vs 3.0±0.7 mm, 0.78±0.15 vs 0.51±0.11 mm, P=0.001, respectively). Simple linear regression analysis showed no significant correlation between SAT and insulin resistance (r=0.170, P=0.253), whereas there was significant correlation between SAT and BMI, age and IMT (r=0.625, P=0.02, r=0.589, P=0.001, r=0.343, P=0.02, respectively). As an optimal cutoff point, a SAT thickness of 4.1 mm determined insulin resistance with 90% sensitivity and 61% specificity.Conclusions:Our study showed that SAT was significantly correlated with age, BMI and IMT, but not insulin resistance. However, our findings suggest that a 4.1 mm cutoff of SAT thickness might be used as a simple, inexpensive and non-invasive screening method because of its ability to predict insulin resistance with high sensitivity in obese children.


Endocrine Practice | 2013

A case of rapid-onset obesity with hypothalamic dysfunction, hypoventilation, autonomic dysregulation, and neural crest tumor: ROHHADNET syndrome.

Ayhan Abaci; Gönül Çatlı; Erhan Bayram; Tolga Koroglu; Hatice Nur Olgun; Kamer Mutafoglu; Ayşe Semra Hız; Handan Cakmakci; Ece Böber

OBJECTIVE Rapid-onset obesity with hypoventilation, hypothalamic dysfunction, and autonomic dysregulation (ROHHAD) is a rare disorder that mimics both common obesity and genetic obesity syndromes along with several endocrine disorders during early childhood. We aim to present the clinical features, laboratory and imaging results, and treatment outcomes of a patient with ROHHAD syndrome. METHODS In this case report, we describe a 26-month-old boy who was admitted to our emergency department with dyspnea and cyanosis and was suspected to have ROHHAD syndrome due to his rapid-onset obesity and alveolar hypoventilation. RESULTS A thoracal and abdominal magnetic resonance imaging was performed to demonstrate a possible accompanying neural crest tumor and it provided a yet asymptomatic retroperitoneal ganglioneuroblastoma. Based on these findings, the patient was diagnosed as ROHHADNET syndrome. CONCLUSION Because of the high prevalence of cardiorespiratory arrest and probability of accompanying tumors, early recognition of ROHHAD syndrome is important. To prevent presumptive mortality and morbidity, ROHHAD syndrome should be considered in all cases of rapid and early-onset obesity associated with hypothalamic-pituitary endocrine dysfunctions.


Journal of Pediatric Endocrinology and Metabolism | 2010

Decreased Plasma Apelin Levels in Pubertal Obese Children

Serkan Tapan; Emre Tascilar; Ayhan Abaci; Sonmez A; Kilic S; Erbil Mk; Ozcan O

ABSTRACT Background: Apelin is a recently defined peptide relevant to the mechanism of obesity-related disorders. There has been no report so far about the levels of plasma apelin in obese children. Methods: In this study plasma apelin, adiponectin, and high sensitivity C reactive protein levels were investigated in obese (n=32) and nonobese (n=40) children. The effects of pubertal status on the apelin and adiponectin levels were evaluated as well. Results: When compared to nonobese controls, the obese children had significantly lower plasma apelin (p= 0.004), adiponectin and HDL cholesterol levels (p= 0.001 for both), and higher hs-CRP, triglycerides, insulin and Homeostasis Model Assessment (HOMA-IR) indexes (p< 0.001 for all). The difference between the apelin levels was present only in the pubertal period (p=0.002). Conclusions: The results of the present study indicate that plasma apelin levels are lower in child obesity and pubertal state is an important determinant of plasma apelin levels.


Journal of Pediatric Endocrinology and Metabolism | 2015

Gonadal malignancy risk and prophylactic gonadectomy in disorders of sexual development.

Ayhan Abaci; Gönül Çatlı; Merih Berberoglu

Abstract Disorders of sex development (DSD) are a generic definition including any problem noted at birth where the genitalia are atypical in relation to the chromosomes or gonads. The most important clinical problems in DSD comprise physical and psychological disturbances and the risk of gonadal tumor development. Germ cell tumor risk is lowest (<5%) in patients with defects in androgene action or synthesis (such as complete androgen insensitivity syndrome, 5α-reductase deficiency), whereas the highest risk (15%–60%) is observed in 46,XY gonadal dysgenesis. The presence of Y chromosomal material in the karyotype increases the risk for the development of gonadal tumors. The reported age of tumor development varies based on the etiology of DSD (gonadal dysgenesis, androgen insensitivity syndrome, androgen synthesis defects, mixed gonadal dysgenesis, etc.). In the past, early gonadectomy was recommended for all cases of 46,XY DSD, however, according to current approaches, gonadal tumor risk is predicted based on the molecular diagnosis and the timing of the gonadectomy depends on the result of molecular analysis. Until now, optimal protocol in the management of DSD is still controversial. In addition to that, safe and well-accepted guidelines are needed. There is limited number of prospective studies on timing of a gonadectomy in childhood and adolescence. Therefore, evidence-based data on timing and indications of gonadectomy in patients with DSD are needed. In this review, recent data regarding gonadal malignancy risk in DSD and recommendations on timing of gonadectomy are presented.


Experimental and Clinical Endocrinology & Diabetes | 2013

Low Omentin-1 Levels Are Related with Clinical and Metabolic Parameters in Obese Children

Gönül Çatlı; Ahmet Anık; Ayhan Abaci; Tuncay Kume; Ece Böber

This is the first clinical study evaluating the relation of serum omentin 1 levels with anthropometric and metabolic parameters in obese children with a particular interest to identify the possible role of omentin 1 in childhood obesity and related metabolic disturbances.The study included obese children with a body mass index (BMI)>95th percentile and healthy children with a BMI<85th percentile. The healthy and obese subjects had similar age and gender distribution. Glucose, insulin, lipid profile, and omentin 1 levels were measured to evaluate the metabolic parameters.49 obese children who applied to our department with complaint of weight gain and 30 healthy age and sex matched subjects were enrolled. In obese children BMI, body mass index-standard deviation score (BMI-SDS), systolic blood pressure (SBP), diastolic blood pressure (DBP), mid-arm circumference (MAC), triceps skin fold (TSF), waist circumference (WC), homeostasis model assessment-insulin resistance (HOMA-IR), serum insulin, and triglyceride levels were higher whereas omentin-1 levels were lower than control subjects (p<0.05). In the obese group, omentin 1 level was negatively correlated with BMI, insulin, HOMA-IR, and WC, while no significant correlation was observed with other parameters (p>0.05). Additionally, although statistically insignificant, patients with IR (n=31) had lower omentin-1 levels compared to obese children without IR (n=18).Our data indicates that serum omentin 1 levels are i) lower in obese children and ii) negatively correlated with BMI, WC, HOMA-IR and insulin levels suggesting that omentin 1 might be a biomarker for metabolic dysfunction also in childhood and adolescence. Lower omentin 1 levels tended to be associated with insulin resistance however this association failed to reach statistical significance. Further studies in larger populations are needed to better-define the relation of omentin 1 and insulin resistance in obese children.

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Ece Böber

Dokuz Eylül University

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Ahmet Anık

Dokuz Eylül University

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Korcan Demir

Dokuz Eylül University

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Hale Tuhan

Dokuz Eylül University

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Sezer Acar

Dokuz Eylül University

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Tuncay Kume

Dokuz Eylül University

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