Biomedical subjects

Mahmut Ilker Yilmaz

Publications and source records attributed to Mahmut Ilker Yilmaz.

15 recordsLinked to original sources

PubMed2006

Plasma visfatin levels in patients with newly diagnosed and untreated type 2 diabetes mellitus and impaired glucose tolerance.

Visfatin, a new adipokine, facilitates adipogenesis and has insulin-mimetic properties. We aimed to investigate the plasma visfatin levels in patients with newly diagnosed and untreated type 2 diabetes mellitus (T2DM) and impaired glucose tolerance (IGT), who had no obesity or hypertension. Twenty-two patients with T2DM, 18 subjects with IGT and 40 healthy controls were enrolled. Visfatin levels were measured along with the BMI, blood pressure, lipids, glucose, insulin, adiponectin and hsCRP levels, and HOMA-IR indexes. Age, sex and BMI were similar in all groups. Visfatin levels were higher in the diabetic group than the controls (p=0.01). There was no significant difference in the visfatin levels between the T2DM and IGT groups as well as IGT group and healthy controls. Plasma visfatin concentrations did not differ between men and women. Visfatin levels did not correlate with BMI, blood pressure, plasma adiponectin, insulin, hsCRP, glucose and lipid levels or HOMA-IR indexes in the three groups. These results indicate that hyperglycemia causes an increase in plasma visfatin levels and, as in people with T2DM but not with IGT, this increase gets more prominent as the glucose intolerance worsens.

Adult↗

PubMed2006

Adiponectin and insulin resistance in young and healthy smokers.

Smoking is closely associated with insulin resistance, though the mechanism is not clear. Adiponectin, a novel anti-atherosclerotic and anti-inflammatory adipose tissue product, which is closely associated with insulin resistance, was reported to be low in smokers with cofactors for atherosclerosis. However, the effects of smoking on circulating adiponectin levels in otherwise healthy people are unknown. In this study, a case control design was implemented to search for the effect of smoking on plasma adiponectin and insulin sensitivities in healthy people. Sixty-four healthy male smokers, with no family history of hypertension and diabetes mellitus were compared with appropriate 36 age and body mass index matched controls. Both the patients and controls were the soldiers of a troop with regular daily physical activity. Plasma adiponectin, high sensitive C-reactive protein (hsCRP), insulin and lipid levels, and insulin sensitivity as assessed by homeostasis model assessment index (HOMA) of the smokers were measured and compared with those of the controls. The plasma adiponectin, hsCRP, insulin levels and HOMA indexes of the two groups were similar. These parameters were not affected by the amount of cigarettes per day. HDL-cholesterol levels were lower (p = 0.01) and systolic blood pressures were higher (p = 0.02) in the smokers. These results indicate that smoking may not affect plasma adiponectin and insulin levels in young and healthy men with high exercise capacity.

Adiponectin↗

PubMed2006

Hyperbaric oxygen treatment augments the efficacy of a losartan regime in an experimental nephrotic syndrome model.

BACKGROUND/AIMS: Proteinuria is associated with oxidant stress and inflammation. Hyperbaric oxygen (HBO) treatment has anti-inflammatory and anti-oxidant effects. The aim of the study was to investigate the benefits of HBO treatment on an experimental nephrotic syndrome model. METHODS: 50 male Sprague-Dawley rats weighing 255 +/- 39 g were housed. Forty rats were injected 6 mg/kg adriamycin into tail veins under anesthesia to induce nephrosis, while 10 rats were spared as sham control. After the stabilization of proteinuria at the sixth week, the rats were treated for 6 weeks by losartan (n = 10, 30 mg/kg/day), HBO (n = 10, 2.8 atmosphere absolute, 90 min/day), HBO + losartan (n = 10) and vehicle (n = 10). Protein carbonyl (PCO), superoxide dismutase (SOD) and glutathione peroxidase (GPx) were analyzed from tissue specimens. Biochemical markers were studied from venous samples and 24-hour urine was collected for proteinuria. The surviving animals at 12 weeks (vehicle group (n = 6), HBO (n = 6), losartan (n = 8), HBO + losartan (n = 10) were sacrificed. Glomerular sclerosis, tubulointerstitial and blood vessel changes were determined by semiquantitative scoring. RESULTS: The PCO levels increased (p < 0.001), and the GPx and SOD levels decreased (p < 0.001 for both) in the nephrotic rats. In losartan and HBO groups GPx levels increased (p = 0.001, p = 0.002 respectively), but PCO and SOD levels did not change. The combination of HBO with losartan significantly increased the GPx and SOD levels (p = 0.001 for both) and decreased PCO levels (p = 0.005). HBO but not losartan significantly reduced proteinuria (p < 0.001). The combination of HBO and losartan reduced proteinuria better than the single losartan regime (p < 0.001). The effect of the combination was also noticed on the histological examination of the kidneys. The activities, appetites, weight gains, and improvement of edema were better in the HBO combined with losartan regime. CONCLUSIONS: These results indicate that the addition of HBO therapy to a conventional regime, angiotensin receptor blockers, has significant benefits in the management of proteinuria. Future clinical studies are needed to elucidate the role of HBO and other antioxidant strategies in the treatment of proteinuria.

Animals↗

PubMed2006

The determinants of endothelial dysfunction in CKD: oxidative stress and asymmetric dimethylarginine.

BACKGROUND: Oxidative stress is related to endothelial dysfunction (ED) and cardiovascular outcomes in patients with chronic kidney disease. Increased asymmetric dimethylarginine (ADMA) levels are among the main causes of ED. We aim to investigate any association between ED and ADMA levels, as well as levels of oxidative stress markers, in patients with chronic kidney disease. METHODS: One hundred fifty-nine patients without diabetes with chronic kidney disease were studied. Staging was performed according to glomerular filtration rate, determined as stages 1 to 5 according to the Kidney Disease Outcomes Quality Initiative (n = 30, 33, 28, 32, and 36, respectively). The control group consisted of 30 healthy subjects. Oxidative stress markers (plasma malondialdehyde [MDA], erythrocyte superoxide dismutase [SOD], glutathione peroxidase [GSH-Px]), trace elements (erythrocyte zinc [EZn], erythrocyte copper [ECu]), plasma selenium (Se), and serum ADMA were studied. Brachial artery endothelium-dependent vasodilatation (FMD) was calculated for all. RESULTS: FMD, SOD, GSH-Px, EZn, ECu, and Se values were lower, whereas MDA and ADMA levels were higher in patients than controls. Glomerular filtration rate correlated negatively with MDA and ADMA levels and positively with FMD, SOD, and GSH-Px values. These parameters were significantly different among patients with stages 2, 3, 4, and 5 (hemodialysis group; P < 0.001 for all). Regression analysis showed that ADMA (beta = -0.228; P < 0.01), SOD (beta = 0.405; P < 0.001), and oxidized low-density lipoprotein levels (beta = -0.428; P < 0.001) were related independently to FMD, whereas glomerular filtration rate was not involved in the model. CONCLUSION: The present results imply that FMD, oxidative stress, and ADMA levels all are associated with stage of chronic kidney disease. Additionally, levels of oxidative stress markers and ADMA independently determine endothelial function.

Adult↗

PubMed2005

Endothelial functions improve with decrease in asymmetric dimethylarginine (ADMA) levels after renal transplantation.

BACKGROUND: Chronic kidney disease (CKD) is associated with increased cardiovascular events. The relationships between the markers of inflammation and endothelial dysfunction were investigated both before and after living donor kidney transplantation. METHODS: Twenty-seven renal transplant patients were studied. Eleven patients (six male, five female) were on cyclosporine A, whereas 16 patients (nine male, seven female) were treated with tacrolimus based regimes. Twenty-seven subjects (12 males, 15 females) were studied as controls. Plasma adiponectin, high sensitive C reactive protein (hsCRP), Asymetric dimethyl arginine (ADMA) levels were studied before transplantation and on days 1, 3, 7, 14, and 28. The brachial artery flow mediated dilatation (FMD) was studied before transplantation and on the 28th day. RESULTS: Serum hsCRP and ADMA levels decreased significantly from the first posttransplantation day on each measurement (P<0.001 for all) while the decrement of plasma adiponectin started in the third day (P<0.001 for all). The FMD was lower in the patients than the control group (P<0.001) and improved significantly in the 28th day of transplantation (P<0.001). CONCLUSIONS: The results indicate that ADMA is associated with FMD in CKD both before and after kidney transplantation. Endothelial functions improve at the very beginning of the posttransplantation period with accompanying reduction in ADMA and hsCRP levels.

Adult↗

PubMed2005

Assessment of oxidative stress in the early posttransplant period: comparison of cyclosporine A and tacrolimus-based regimens.

BACKGROUND: Oxidative stress is one of the leading causes of cardiovascular morbidity and mortality in chronic kidney disease. Although it is clear that many metabolic abnormalities improve, the effects of kidney transplantation on oxidative state are obscure. METHODS: Twenty-three kidney transplant patients were included in the study. Eleven patients (mean age 27.9+/- 9.1 years) were treated with cyclosporine A (CsA) whereas 12 patients (mean age 22.4 +/- 3.4 years) were treated with tacrolimus. Twenty-three healthy subjects served as controls. None of the patients or controls suffered from diabetes mellitus or an acute infection at the time of the study. Plasma malondialdehyde (MDA), plasma selenium (Se), erythrocyte glutathione peroxidase (GSH-Px), erythrocyte superoxide dismutase (SOD), erythrocyte Zn (EZn), and erythrocyte Cu (ECu) levels were studied before and in the 1st, 3rd, 7th, 14th and 28th days after the transplantation. RESULTS: The GSH-Px, SOD, ECu, EZn and selenium levels were lower and MDA levels were higher in patients than controls before transplantation (p < 0.001 for all). MDA levels decreased and SOD, GSH-Px, ECu, EZn levels increased in parallel to the decrement of serum creatinine levels following the renal transplantation. No difference was found among the patients regarding the treatment regime. CONCLUSION: The study data suggest that the improvement in oxidative state parameters begins at the first day of renal transplantation and continues at the 28th posttransplant day in living donor transplantations.

Adult↗

PubMed2005

Blockade of the renin-angiotensin system increases plasma adiponectin levels in type-2 diabetic patients with proteinuria.

BACKGROUND/AIMS: Adiponectin seems to be an important modulator for metabolic and vascular diseases. A case study was designed to measure plasma adiponectin levels and to investigate the effects of angiotensin-converting enzyme inhibitors on adiponectin levels in type-2 diabetic patients with proteinuria. METHODS: Forty-nine patients (28 males, 21 females) and 23 healthy volunteers (13 males, 10 females) were included in the case study. Patients with proteinuria were treated with 5 mg/day ramipril (n = 21) for 4 weeks. RESULTS: Adiponectin levels of patients were significantly lower than those of healthy volunteers (p < 0.001). There were significant negative correlations between adiponectin concentrations and insulin levels as well as the homeostasis model assessment (HOMA) index in the patient group (r = -0.655, p < 0.001; r = -0.469, p = 0.001, respectively). There was also a significant negative correlation between plasma adiponectin concentrations and the degree of proteinuria (r = -0.912, p < 0.001). Plasma adiponectin levels in patients with proteinuria (n = 21; 4.81 +/- 3.17 microg/ml) were significantly lower than those without proteinuria (n = 28; 10.25 +/- 2.03 microg/ml; p < 0.001). After the treatment period, adiponectin levels significantly increased (p < 0.001) and proteinuria, plasma insulin, and HOMA indexes significantly decreased in the treatment group (p < 0.001, p < 0.001, p = 0.002, respectively). CONCLUSIONS: The results suggest that adiponectin is inversely correlated with proteinuria and treatment with ramipril both corrects proteinuria and increases the low adiponectin levels in diabetic patients.

Adiponectin↗

PubMed2005

Prostate cancer and adiponectin.

OBJECTIVES: To search for any relation between plasma adiponectin levels and the cellular differentiation or progression of prostate cancer (PCa). PCa is becoming an increasingly important public health problem, particularly for those countries with a trend toward an aging population. Because insulin resistance in the setting of obesity is associated with the development of PCa, we hypothesized that decreased adiponectin levels might underlie the association between PCa and obesity/insulin resistance. METHODS: In this study, we investigated plasma adiponectin levels in 30 patients with PCa, 41 subjects with benign prostatic obstruction, and 36 healthy individuals. The body mass index and age of the groups were similar. Patients with PCa were stratified into two groups according to the spread of the disease as organ-confined and advanced disease and into three groups according to grade (low, intermediate, and high grade determined by a Gleason sum of less than 5, between 5 and 7, and more than 7, respectively). RESULTS: Plasma adiponectin levels were significantly lower in the PCa group than in the benign prostatic obstruction group or controls (P < 0.001 for both). Additionally, the plasma adiponectin levels were significantly lower in the advanced disease group than in the organ-confined PCa group (P = 0.012). Significant negative associations were found between plasma adiponectin levels and prostate-specific antigen levels or biopsy Gleason scores in the PCa group. The plasma adiponectin levels of those with high-grade PCa were also significantly lower than those for both the low-grade and intermediate-grade groups (P < 0.001 for both). CONCLUSIONS: The results of the present study imply that plasma adiponectin levels are not only lower in patients with PCa but are also negatively associated with the histologic grade and disease stage. Future prospective studies are recommended to establish any causal relation between PCa and plasma adiponectin levels.

Adiponectin↗

PubMed2005

The bisphosphonate zoledronic acid inhibits the development of plasmacytoma induced in BALB/c mice by intraperitoneal injection of pristane.

OBJECTIVES: Bisphosphonates (BPs) are mostly used in the palliative care of myeloma-associated osteolytic lesions. Recent studies have suggested that BPs may also exert direct antitumor effects on myeloma cells. We have investigated the effect of the potent bisphosphonate, zoledronic acid (ZOL), on the development of pristane (2,6,10,14-tetramethylpentadecane)-induced plasmacytoma (PCT) in six-week-old BALB/c mice. METHODS: Different groups of pristane-treated mice also received ZOL (100 microg/kg) commencing after the development of PCT or ZOL (20 microg/kg) from the first day. Control groups received pristane alone, ZOL alone (20 microg/kg), or phosphate-buffered saline. The study was terminated on day 300, and the remaining mice were autopsied and abdominal tissues were examined histologically for PCT. RESULTS AND CONCLUSIONS: Statistical analysis revealed a significant delay in PCT development in the group receiving pristane plus ZOL (20 microg/kg) from the first day compared to the groups receiving pristane alone and pristane combined with ZOL (100 microg/kg) after the appearance of PCT (Log-rank, P = 0.0001 and 0.0001; respectively). Kaplan-Meier analysis revealed a significant difference in survival between the group treated with pristane alone and the groups receiving pristane plus ZOL (20 microg/kg) from the first day or ZOL (100 microg/kg) after the appearance of PCT (Log-rank, P = 0.016 and 0.023; respectively). These results indicate a direct anti-tumor effect of ZOL in pristane-induced PCT development BALB/c mice, which may contribute to their significantly increased survival. This hypothesis should now be further investigated in clinical trials.

Animals↗

PubMed2005

The association of plasma adiponectin levels with hypertensive retinopathy.

OBJECTIVE: Previous studies have demonstrated that low plasma adiponectin concentrations are associated with essential hypertension. It has also recently been shown that adiponectin plays an essential role in the modulation of angiogenesis. These data led us to hypothesize that adiponectin might contribute to end-organ damage in hypertension. METHODS: In the present study we have evaluated the relationship between plasma adiponectin concentrations and hypertensive retinopathy. One hundred and ten patients newly diagnosed with essential hypertension (EHT) (mean age, 46.79+/-5.0 years; body mass index (BMI), 26.47+/-2.23 kg/m(2); male/female ratio, 58/52) and 57 healthy normotensive control subjects (NT) (mean age, 46.84+/-5.4 years; BMI, 26.66+/-2.65 kg/m(2); male/female ratio, 33/24) were enrolled. RESULTS: Plasma adiponectin levels were significantly lower in EHT than in NT (P < 0.001). In addition, adiponectin concentrations were strongly correlated with systolic and diastolic blood pressures in EHT (r = -0.757, P < 0.001; r = -0.761, P < 0.001) while there was no correlation in the NT group. Plasma adiponectin in patients with grade 0 hypertensive retinopathy (n = 52) was significantly higher than that of the patients with grade 1 (n = 30) and 2 (n = 28) hypertensive retinopathy (P < 0.001 for each). Plasma adiponectin in patients with grade 0 hypertensive retinopathy was also significantly lower than that in the NT group (P < 0.001). The estimated threshold of plasma adiponectin concentration for hypertensive retinopathy was 17 microg/ml. This critical adiponectin level served largely to separate patients with retinopathy from those without. CONCLUSION: Our results have shown that plasma adiponectin concentrations decrease progressively with higher grades of hypertensive retinopathy even after correction for other atherogenic risk factors, suggesting that a critical adiponectin level is needed for the development of retinopathy.

Adiponectin↗

PubMed2004

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonist increases plasma adiponectin levels in type 2 diabetic patients with proteinuria.

Adiponectin appears to be an important modulator for metabolic and vascular diseases. A case-controlled study was designed to measure plasma adiponectin levels and investigate the effects of rosiglitazone on adiponectin levels in type 2 diabetic patients with proteinuria. Sixty-four patients (mean age, 46.1+/-4.6 yr; 30 male, 34 female) and 26 healthy volunteers (mean age, 45.3+/-4.8 yr; 14 male, 12 female) were included. Patients with proteinuria were treated with 4-mg/d rosiglitazone (n=21, 10 males, 11 females) for 4 wk. Adiponectin levels in patients were significantly lower than those of controls (p<0.001). There were significant negative correlations between adiponectin concentrations and insulin levels as well as homeostasis model assessment (HOMA) index in patient's group (r=- 0.538, p<0.001; r=- 0.393, p=0.001, respectively). There was also a significant negative correlation between plasma adiponectin concentrations and the degree of proteinuria (r=- 0.526, p=0.002). Plasma adiponectin levels in patients with proteinuria (n=31; 3.91+/-2.57 microg/mL) were significantly lower than those without proteinuria (n=33; 10.15+/-1.97 microg/mL) (p<0.001). After the treatment period, adiponectin levels significantly increased (p<0.001) and proteinuria, plasma insulin, and HOMA indexes significantly decreased in treatment group (p<0.001, p<0.001, p<0.001, respectively). The results suggest that adiponectin is inversely correlated with proteinuria and treatment with peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist rosiglitazone both corrects proteinuria and increases the low adiponectin levels in diabetic patients.

Adipocytes↗

PubMed2004

Adiponectin may play a part in the pathogenesis of diabetic retinopathy.

OBJECTIVES: To measure plasma adiponectin concentrations in patients with type 2 diabetes and to investigate any association with the severity of diabetic retinopathy, because adiponectin seems to be an important modulator for metabolic and vascular diseases. METHODS: Seventy-four patients (mean age 46.8+/-5.1 years; body mass index (BMI), 26.8+/-2.10 kg/m(2)) and 54 healthy volunteers (mean age 46.8+/-5.4 years; BMI 26.47+/-2.33 kg/m(2)) were included. RESULTS: Adiponectin concentrations in the patients were significantly lower than those in controls (4.71+/-2.11 microg/ml for patients, n=74; 15.95+/-3.72 microg/ml for controls, n=54; P<0.001). In the patients group there was a significant negative correlation between adiponectin and homeostasis model assessment index (r=-0.318, P=0.006 respectively). Plasma adiponectin concentrations in patients with proliferative diabetic retinopathy (n=20; 3.16+/-1.83 microg/ml) or non-proliferative diabetic retinopathy (n=24; 3.97+/-1.47 microg/ml, P=0.014) were significantly lower than those in patients without diabetic retinopathy (n=30; 6.30+/-1.57 microg/ml, P=0.001). When the presence of diabetes was defined as the final variable in the conditional logistic regression model with the adiponectin concentration as the continuous variable, adiponectin was significantly involved in the model. CONCLUSION: The results show that adiponectin concentrations are lower in patients with type 2 diabetes and that the concentrations are associated with the severity of diabetic retinopathy. Our findings suggest that adiponectin may take part in the pathogenesis of diabetic retinopathy.

Adiponectin↗

PubMed2002

The renin-angiotensin-aldosterone system (RAAS) and its relation with calcium homeostasis in male obesity.

BACKGROUND: The aim of our study was to determine whether alterations of the vitamin D-endocrine system and the renin-angiotensin-aldosterone system occur in male obesity and influence each other. MATERIAL/METHODS: 32 obese male subjects and 21 age-matched healthy male subjects were enrolled in the study. The parameters measured included serum total calcium (Ca), ionized calcium, magnesium (Mg), phosphorus (P), 25-hydroxyvitamin D (25-OHD), supine and upright aldosterone and renin activity, and urinary calcium, magnesium, and phosphorus. RESULTS: Serum total Ca and ionized calcium were slightly, but not significantly lower in obese subjects compared to controls, whereas serum magnesium phosphorus and PTH levels were significantly higher in the obese subjects. Mean urinary calcium and Mg were not significantly different, while urinary P was significantly higher in obese subjects. Mean serum 25OHD was significantly lower in obese subjects. Supine and upright aldosterone and renin were unrelated to BMI or fat mass. Supine aldosterone correlated with serum total calcium, ionized calcium and supine renin activity, but not with other minerals, PTH or 25OHD, whereas upright aldosterone did not correlate with other parameters. Supine renin activity did not correlate with any parameters, whereas upright renin correlated with serum Mg and PTH. There were significant correlations between PTH and BMI or fat mass. Urinary Mg was also related to both BMI and fat mass. CONCLUSIONS: Male obesity is associated with increased serum Mg, P, PTH and urinary P and lower supine aldosterone and 25OHD, but unchanged serum and urinary Ca.

Adult↗

PubMedDate not supplied

Low serum leptin level in colon cancer patients without significant weight loss.

AIMS AND BACKGROUND: Leptin is a protein that affects the metabolic, neuroendocrine, reproductive and hematopoietic systems and is involved in the regulation of body weight. The possible role of leptin in cancer patients, whose aforementioned systems show disorders at various levels, has been investigated by only a few studies and the results are quite contradictory. METHODS: In this study serum leptin levels were investigated in 36 patients with colon cancer having no weight loss or anorexia and in 36 healthy volunteers. Serum leptin levels were measured by radioimmunoassay. RESULTS: Significantly positive correlations were found between serum leptin level and/or body mass index (BMI) in patient and control groups (r = 0.842, P < 0.001 and r = 0.785, P < 0.001; r = 0.880, P < 0.001 and r = 0.523, P = 0.001). Serum leptin levels of colon cancer patients were significantly lower than those of the control group (8.79 vs 15.95 ng/mL, P = 0.003). BMI and age of the colon cancer patients were not different from those of the control group. Serum leptin levels of early-stage patients (n = 15) did not differ from those of advanced-stage patients (n = 21) (7.74 vs 9.54 ng/mL, P = 0.542), nor was there any difference in the serum leptin levels of patients who did and patients who did not receive chemotherapy. There was no correlation in cancer patients between serum leptin levels and CEA or CA19-9 (r = 0.015, P = 0.929 and r = 0.097, P = 0.574). CONCLUSION: Low serum leptin levels found in colon cancer patients without weight loss suggest that another mechanism regulating the leptin levels might be responsible.

Body Mass Index↗

PubMedDate not supplied

Development of squamous cell carcinoma of the tongue during induction chemotherapy for acute myeloid leukemia.

Immunosuppression is a well-recognized cause of skin tumors, in particular squamous cell carcinomas (SCC). In patients with hematological malignancies undergoing chemotherapy, SCC has been reported late in the course of the disease or many years after completion of treatment. Here we report a patient with acute myeloid leukemia who developed a SCC of the tongue while receiving the third course of induction chemotherapy. This is the second such case in the medical literature. The role of immunosuppression, chemotherapy, the malignancy itself and possible genetic predisposition is discussed and the literature on this topic is reviewed.

Aged↗