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Featured researches published by Ahmet Uygun.


Alimentary Pharmacology & Therapeutics | 2004

Metformin in the treatment of patients with non‐alcoholic steatohepatitis

Ahmet Uygun; Abdurrahman Kadayifci; Ahmet Turan Isik; T. Ozgurtas; Salih Deveci; Ahmet Tüzün; Zeki Yesilova; Mustafa Gulsen; Kemal Dagalp

Background : Increased insulin resistance is the major pathogenic mechanism in the development of non‐alcoholic steatohepatitis.


The American Journal of Gastroenterology | 2000

Serum leptin levels in patients with nonalcoholic steatohepatitis

Ahmet Uygun; Abdurrahman Kadayifci; Zeki Yesilova; Ahmet Erdil; Halil Yaman; Mendane Saka; M. Salih Deveci; Sait Bagci; Mustafa Gulsen; Necmettin Karaeren; Kemal Dagalp

OBJECTIVE:Leptin is a peptide hormone that mainly regulates food intake and energy expenditure of human body. A close correlation between serum leptin levels and the percentage of body fat stores is well known. Nonalcoholic steatohepatitis (NASH) is a common disorder which causes serum liver enzyme elevation. In this study, the serum leptin levels were investigated in patients with NASH to determine a possible role in the pathogenesis and in patients with chronic viral hepatitis to ascertain the effect of hepatic inflammation on serum leptin level.METHODS:Forty-nine patients (38 men, 11 women) with NASH diagnosed by biopsy, 32 patients with biopsy-proven chronic viral hepatitis (21 men and 11 women), and 30 healthy adults (17 men, 13 women) enrolled in the study. Fasting blood samples were obtained, and serum leptin levels were measured by ELISA. Body mass index (BMI) was calculated for all subjects, and serum insulin, C-peptide, and lipoprotein levels were also detected.RESULTS:The mean serum leptin levels (±SEM) were 6.62 ± 0.71, 4.24 ± 1.0, and 4.02 ± 0.46 ng/ml in NASH, chronic hepatitis, and the control group, respectively. Mean serum leptin level in the NASH group was significantly higher than those in the other groups tested. BMI was also slightly higher in the NASH group when compared to the other groups (26.7 ± 0.3, 23.7 ± 0.6, and 24.6 ± 0.3, respectively). There was a significant correlation between BMI and serum leptin levels when all the subjects were evaluated together (NASH, hepatitis, and control groups, r= 0.337, p= 0.012) but not in the NASH group when evaluated alone (r= 0.238, p= 0.1). Of the predisposing factors for NASH, obesity was observed in 24% of patients and hyperlipidemia in 67%. Serum cholesterol and triglyceride levels were significantly higher in the NASH group than those in controls (p < 0.05). It has been detected that most of these patients consumed high amounts of fat in their dietary habits.CONCLUSIONS:The serum leptin levels were significantly higher in patients with NASH, while they were not affected by chronic hepatitis. This elevation is out of proportion to BMI of these patients and may be related to hyperlipidemia in most. Elevated serum leptin levels, therefore, may promote hepatic steatosis and steatohepatitis.


The American Journal of Gastroenterology | 2005

Systemic Markers of Lipid Peroxidation and Antioxidants in Patients with Nonalcoholic Fatty Liver Disease

Zeki Yesilova; Halil Yaman; Cagatay Oktenli; Ayhan Ozcan; Ahmet Uygun; Erdinc Cakir; S. Yavuz Sanisoglu; Ahmet Erdil; Yuksel Ates; Murat Aslan; Ugur Musabak; M. Kemal Erbil; Necmettin Karaeren; Kemal Dagalp

OBJECTIVES:The aim of the present study was to examine the systemic parameters of oxidative stress and antioxidants in patients with nonalcoholic fatty liver disease and investigate the relationship between these parameters and clinical and biochemical outcomes.METHODS:Fifty-one male patients with nonalcoholic fatty liver disease (group I), 30 age-matched and body mass index (BMI)-matched healthy male subjects, and 30 age-matched male patients with chronic viral hepatitis (group II) were enrolled in the study.RESULTS:Increased systemic levels of malondialdehyde and depletion of antioxidants such as coenzyme Q10, CuZn-superoxide dismutase, and catalase activity were observed in group I. Coenzyme Q10 and CuZn-superoxide dismutase correlated negatively with increasing necroinflammatory activity and fibrosis. Body fat was negatively associated with plasma coenzyme Q10 levels, while an inverse association was found between plasma catalase levels and TG. However, LDL was positively associated with plasma malondialdehyde levels. CuZn-superoxide dismutase levels were negatively associated with glucose, insulin, and HOMA-IR. In addition, the levels of CuZn-superoxide dismutase correlated significantly in a negative manner with BMI.CONCLUSIONS:Our results concerning correlations suggest that disturbances in BMI, body fat, and lipid metabolism may contribute to altered oxidative status in NAFLD, and insulin resistance may be related to decreased antioxidants in NAFLD as well as products of lipid peroxidation. However, although our results suggest interesting correlations, this different mostly “weak” relationships must be taken with caution.


Journal of Gastroenterology and Hepatology | 2005

Elevated plasma homocysteine concentrations as a predictor of steatohepatitis in patients with non‐alcoholic fatty liver disease

Mustafa Gulsen; Zeki Yesilova; Sait Bagci; Ahmet Uygun; Ayhan Ozcan; C Nuri Ercin; Ahmet Erdil; S. Yavuz Sanisoglu; Erdinc Cakir; Yuksel Ates; M. Kemal Erbil; Necmettin Karaeren; Kemal Dagalp

Background:  Although steatosis is common in patients with severe hyperhomocysteinemia due to deficiency of cystathionine β‐synthase, there are no satisfactory data on homocysteine concentrations in patients with non‐alcoholic fatty liver disease. The main aim of the present study was to evaluate the clinical significance of plasma homocysteine concentrations in patients with non‐alcoholic fatty liver disease.


Journal of Gastroenterology and Hepatology | 2004

Leptin levels in the acute stage of ulcerative colitis

Ahmet Tüzün; Ahmet Uygun; Zeki Yesilova; A. Melih Ozel; Ahmet Erdil; Halil Yaman; Sait Bagci; Mustafa Gulsen; Necmettin Karaeren; Kemal Dagalp

Background and Aims:  Leptin, a recently discovered protein, acts as a hormonal feedback signal in regulating adipose tissue mass via hypothalamic mechanisms. Inflammatory bowel disease is often associated with anorexia and weight loss. The aim of the present study was to investigate serum leptin levels during the time course of the acute phase of ulcerative colitis (UC) and to evaluate whether leptin leads to anorexia and bodyweight loss in these patients.


Clinical Therapeutics | 2008

Comparison of sequential and standard triple-drug regimen for Helicobacter pylori eradication: a 14-day, open-label, randomized, prospective, parallel-arm study in adult patients with nonulcer dyspepsia.

Ahmet Uygun; Abdurrahman Kadayifci; Zeki Yesilova; Mukerrem Safali; Seyfettin Ilgan; Necmettin Karaeren

BACKGROUND The eradication rates of Helicobacter pylori with standard treatments are decreasing worldwide. OBJECTIVES The primary aim of this study was to compare the eradication success of a 14-day sequential regimen with proton pump inhibitor (PPI)-based triple treatment. The secondary objectives of the study were to evaluate the effect of gastritis score and smoking on eradication rates as well as evaluation of compliance and tolerability of both regimens. METHODS Consecutive H pylori-positive patients with nonulcer dyspepsia were randomized into 1 of 2 groups in this 14-day, open-label, randomized, prospective, parallel-arm study. An upper endoscopy with biopsy and (14)C-urea breath test ((14)C-UBT) were performed before enrollment. The first group was administered a sequential regimen consisting of pantoprazole 40 mg and amoxicillin 1 g for 7 days, followed by pantoprazole 40 mg, tetracycline 500 mg, and metronidazole 500 mg for the next 7 days. The second group was administered pantoprazole 40 mg, amoxicillin 1 g, and clarithromycin 500 mg (PAC group) for 14 days. All drugs were administered BID, with the exception of tetracycline, which was administered QID. Eradication was confirmed by (14)C-UBT 6 weeks after the end of the treatment. Histologic examination and (14)C-UBT were conducted by investigators blinded to the protocols. Patients were asked to report any adverse events (AEs) during the treatment period. RESULTS Three hundred white patients were enrolled in the study and evenly randomized into the sequential treatment group (98 males and 52 females; mean age, 40.2 years) and the PAC group (86 males and 64 females; mean age, 41.2 years). A total of 274 patients completed the study per protocol (PP). Twenty-six patients discontinued: lost to follow-up (16), withdrawn due to AEs (9); and noncompliance (1). The intent-to-treat (ITT) and PP H pylori eradication rates were 72.6% and 80.1% in the sequential group, and 58% and 63% in the PAC group, respectively. The eradication rate was significantly higher in the sequential group compared with the PAC group in both the ITT and PP populations (P=0.01 and P=0.002, respectively). The eradication rates were higher in nonsmoking patients compared with smoking patients both in the sequential group (85.8% vs 70.5%) and the PAC group (67.7% vs 53.3%), but the results were not statistically significant when the groups were analyzed separately. Overall, 32 patients (10.7%) reported an AE. Treatment was discontinued in 9 patients because of serious AEs (sequential group--abdominal pain [2 patients], diarrhea [1], chest pain [1], and vaginal pruritus [1]; PAC group--nausea/vomiting [2], chest pain [1], and numbness [1]). There were no significant between-group differences in regard to compliance or AEs. Univariate analyses found no significant effect of sex, age, alcohol consumption, antacid usage, or gastritis score on the eradication rates. CONCLUSIONS A 14-day sequential treatment regimen achieved a significantly higher eradication rate of H pylori compared with standard PPI-based triple regimen in this small selected population. Large, double-blind, controlled studies are needed to confirm these results.


Journal of Gastroenterology and Hepatology | 2005

Enteral nutrition via percutaneous endoscopic gastrostomy and nutritional status of patients: five-year prospective study.

Ahmet Erdil; Mendane Saka; Yuksel Ates; Ahmet Tüzün; Sait Bagci; Ahmet Uygun; Zeki Yesilova; Mustafa Gulsen; Necmettin Karaeren; Kemal Dagalp

Background:  Since it was described in 1980, percutaneous endoscopic gastrostomy (PEG) has been a widely used method for insertion of a gastrostomy tube in patients who are unable to swallow or maintain adequate nutrition. The aim of the present paper was to determine the complications of PEG insertion and to study pre‐ and post‐procedural nutritional status.


Journal of Gastroenterology and Hepatology | 2008

Decreased oxidation susceptibility of plasma low density lipoproteins in patients with Gilbert's syndrome

Zeki Yesilova; Muhittin Serdar; C Nuri Ercin; Alp Gunay; Guldem Kilciler; Adnan Haşimi; Ahmet Uygun; Ismail Kurt; M. Kemal Erbil; Kemal Dagalp

Background and Aim:  The association of hyperbilirubinemia in Gilberts syndrome (GS) with a decrease in prevalence of coronary artery disease is a well‐known phenomenon. In this study, the state of low‐density lipoprotein (LDL) oxidation which has been postulated to be a significant determinant at the etiopathogenesis of atherosclerotic disorders was investigated among individuals with GS.


The American Journal of Gastroenterology | 2005

Increased Acylation Stimulating Protein Concentrations in Nonalcoholic Fatty Liver Disease are Associated with Insulin Resistance

Zeki Yesilova; Metin Ozata; Cagatay Oktenli; Sait Bagci; Ayhan Ozcan; S. Yavuz Sanisoglu; Ahmet Uygun; Halil Yaman; Necmettin Karaeren; Kemal Dagalp

OBJECTIVES:As acylation stimulating protein (ASP) acts on adipocytes mainly as a paracrine factor to increase triglyceride synthesis and storage; hypothetically, it may play a similar role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD).METHODS:Forty-six male patients with NAFLD (group A), age-matched 30 male patients with chronic viral hepatitis (group B) and 30 age-matched and body mass index (BMI)-matched healthy male subjects were enrolled in the study.RESULTS:Among the NAFLD patients, 10 patients (24.4%) had simple steatosis and 36 patients (69.6%) had nonalcoholic steatohepatitis (NASH). The mean levels of ASP, complement 3, insulin, C-peptide, HOMA-IR, triglyceride, and very low-density lipoprotein (VLDL) were significantly higher in group A patients than both controls and group B. ASP levels correlated significantly in a positive manner with BMI, insulin, and HOMA-IR.CONCLUSIONS:Dysregulation of the ASP pathway may have important metabolic consequences in NASH and is associated with insulin resistance.


Journal of Digestive Diseases | 2007

The efficacy of bismuth containing quadruple therapy as a first-line treatment option for Helicobacter pylori.

Ahmet Uygun; Abdurrahman Kadayifci; Mukerrem Safali; Seyfettin Ilgan; Sait Bagci

BACKGROUND:  Helicobacter pylori eradication rates have tended to decrease recently, mostly due to increasing antibiotic‐resistance. The present study aimed to compare the efficacy of bismuth‐based quadruple regimen with proton pump inhibitor‐based triple regimen for eradication of H. pylori.

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Sait Bagci

Military Medical Academy

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Hakan Demirci

Military Medical Academy

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Zulfikar Polat

Military Medical Academy

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Ahmet Tüzün

Military Medical Academy

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Kadir Ozturk

Military Medical Academy

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Zeki Yesilova

Military Medical Academy

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Ahmet Erdil

Military Medical Academy

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Kemal Dagalp

Military Medical Academy

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