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Biomedical subjects

M Güven

Publications and source records attributed to M Güven.

13 recordsLinked to original sources
PubMed1999

Age-related changes on glucose transport and utilization of human erythrocytes: effect of oxidative stress.

BACKGROUND: Normal aging is associated with an impairment in glucose homeostasis. METHODS: In order to investigate the effect of aging on glucose transport and utilization in erythrocytes, the transport and utilization of glucose were measured in erythrocytes from 10 young (mean age 26 +/- 3 years) and 10 elderly (mean age 70 +/- 7 years) healthy individuals. In addition, the glucose transport and utilization were also measured in the presence of cumene hydroperoxide (CumOOH), a toxic organic hydroperoxide that is known to induce oxidative stress. RESULTS: The levels of glucose transport and utilization were significantly lower in the elderly group than the young group (p < 0.05). The glucose transport and utilization were not altered by CumOOH treatment in either young or elderly individuals. CONCLUSION: These results indicate an age-related decrease in the both glucose transport and utilization in erythrocytes.

Adult↗
PubMed1999

Frequency of flutamide induced hepatotoxicity in patients with prostate carcinoma.

To identify and describe the frequency and severity of hepatotoxicity in patients who received flutamide therapy for prostate cancer, 22 patients were treated with the combination of flutamide and goserilin or orchiectomy. After diagnosis and staging of prostate cancer, baseline results were obtained for a set of five liver function tests (LF Ts). Hepatotoxicity was assessed according to the WHO criteria. After initiation of flutamide therapy, LF Ts were performed at 4, 8 and 12 weeks and every 2 months thereafter. Severe hepatotoxicity appeared in two of 22 (9%) patients. Following the discontinuation of flutamide, one patient died due to acute liver failure. On the other patient an improvement of LF Ts occurred after cessation of flutamide. The observed severe hepatotoxicity in two of 22 (9%) patients occurred more frequent than is predicted in the literature. Patients treated with flutamide, having symptomatic or asymptomatic liver enzyme elevations, should be taken off therapy as soon as possible.

Aged↗
PubMed1999

Endocrine changes in patients with acute organophosphate poisoning.

In critical illness, several drugs and various stressful conditions modify the functions of neurotransmitters which consequently affect the secretion of pituitary hormones. Although the role of neurotransmitters in the regulation of endocrine system is well known, cholinergic actions have been less investigated. In animals, cholinesterase inhibitors were shown to modify the pituitary-thyroid and pituitary-adrenal axes, and to affect prolactin levels. The aim of the present study was to determine the effect of the organophosphate compounds on endocrine system, particularly pituitary hormones. This prospective study was performed in Medical Intensive Care Unit of Erciyes University Medical School Hospital. Twenty-two consecutive patients (ten males and 12 females aged 28+/-8 years) with organophosphate poisoning were included in the study. ACTH (P<0.002), cortisol (P<0.0005) and PRL (P<0.005) levels were significantly higher during poisoning than after resolution of poisoning. FSH levels were significantly lower during poisoning (P<0. 05). Sick euthyroid syndrome was determined in seven patients (31. 8%). Two of them had low fT3 (with normal fT4 and TSH), two had low fT4 (with normal fT3 and TSH) and three had low TSH (with normal fT3 and fT4) levels. Serum levels of these hormones returned to normal values after resolution of poisoning. The present study demonstrated that organophosphate compounds affected PRL, ACTH and cortisol levels, but did not change LH levels. Organophosphate compounds may result in sick euthyroid syndrome. These conditions may be related to the effects of acetylcholine and direct effect of organophosphate compounds.

Adult↗
PubMed1998

The modulation of glucocorticoid receptor content by 3-O-methyl-D-glucose transport in human mononuclear leukocyte in obesity.

Glucocorticoid receptors (GR) and 3-O-methyl-D glucose (3-O-MG) transport were determined in mononuclear leukocytes (MNL) from 11 abdominal obese subjects, 10 pituitary-dependent Cushing's syndrome (Cushing's disease) and 10 healthy controls. Using a whole-cell competitive binding assay and 3H-dexamethasone as tracer, MNL of abdominal obese subjects were found to have 4855 +/- 1389 sites/cell which was significantly lower (p < 0.05) than controls (6234 +/- 1568 sites/cell), although no significant difference was found in the mean serum cortisol level. Their mean Kd (affinity) was also significantly lower than that found in the healthy controls (obese Kd:2.92 +/- 0.84 nmol/l, control Kd: 4.55 +/- 0.67 nM, p < 0.05). On the other hand, the receptor characteristics in Cushing's disease patients were within the normal range. At the same time, 3-O-MG transport was determined in the same subjects. In Cushing's disease, 3-O-MG transport was within the normal range, whereas in abdominal obesity this value was significantly lower than the healthy controls (abdominal obese: 31.90 +/- 8.20; control: 46.26 +/- 12.91 fmol/10(6) cell, min, p < 0.05). We also found a positive correlation between 3-O-MG transport and GR binding capacity in abdominal subjects (r = 0.89, p < 0.001), however we did not find such a correlation in Cushing's disease (r = 0.60, p > 0.05). These results indicated that, in abdominal obesity, the GR binding capacity in MNL is influenced by the changes in glucose transport.

3-O-Methylglucose↗
PubMed1998

Glucocorticoid receptors on mononuclear leukocytes in polycystic ovary syndrome.

OBJECTIVE: Many studies have suggested that there is a possible hormonal dysregulation of hypothalamic-pituitary-adrenal (HPA) axis and an increased cortisol clearance in patients with polycystic ovary syndrome (PCOS). Therefore in this study, we have examined the role of glucocorticoid receptor/s (GR) characteristics in the developing of these abnormalities in patients with PCOS. METHOD: For this purpose, the number and affinity of GR in peripheral mononuclear leukocytes (MNL) of 10 patients with PCOS and 10 healthy women (controls) were determined. RESULTS: There were no significant differences in the number (6500+/-1001 sites/cell and 6352+/-1697 sites/cell, respectively; P > 0.05) and affinity (3.93+/-0.89 nM and 4.49+/-0.71 nM, respectively; P > 0.05) of GR between the PCOS patients and the controls. CONCLUSIONS: These results suggest that the alterations in the HPA axis and in the cortisol metabolism observed in PCOS are not related to GR deficiency.

Adult↗
PubMed1997

Intravenous organophosphate injection: an unusual way of intoxication.

Organophosphate insecticides strongly inhibit both true cholinesterase and pseudocholinesterase activities. In this report, we have reported a patient who injected himself a strong organophosphate compound, methamidophos, and showed the typical clinical picture of organophosphate intoxication. As far as we know, this is the first case of intoxication by intravenous (i.v.) injection. With the appropriate therapy, his symptoms disappeared in a few days.

Adult↗
PubMed1996

Does tuberculosis really cause hypercalcemia?

Hypercalcemia has been known to be associated with tuberculosis. In some studies it has been reported to occur commonly. It seems that the studies in which tuberculosis was complicated by hypercalcemia were retrospective and therefore the other causes of hypercalcemia could not be excluded. We have a great deal of experience concerning tuberculosis and have not seen a patient with hypercalcemia due to tuberculosis itself. Therefore we aimed to investigate whether tuberculosis really cause hypercalcemia in a prospective study. We evaluated 104 patients with tuberculosis aged between 14-85 (mean +/- SD 38.5 +/- 15) years, 73 males and 31 females, and 50 age-matched healthy subjects aged between 19-70 (mean +/- SD 39 +/- 13) years, 33 males and 17 females. No significant differences between the patients and healthy subjects were detected in terms of 250HD3, calcium and phosphate levels. Albumin levels were significantly higher in the control group than in the tuberculous group (p < 0.02). No significant difference was found between the calcium levels measured before the therapy (2.4 +/- 0.1 nmol/L) and after the therapy (2.4 +/- 0.2). We think that patients with tuberculosis are not at risk for hypercalcemia either before or during treatment and the development of hypercalcemia as a result of tuberculosis is rather doubtful and needs to be clarified.

Adolescent↗
PubMed1995

The effect of metformin on insulin receptors and lipid peroxidation in alloxan and streptozotocin induced diabetes.

Biguanides are used for the treatment of non-insulin dependent diabetes mellitus but there is no evidence for an improving action of biguanide on the enhancement of peripheral glucose disposal in type 1 diabetes. It is known that biguanide agents reduce the oxidation of free fatty acids. Using alloxan and streptozotocin (STZ) induced diabetic rats as a model for type 1 diabetes mellitus, we measured insulin binding capacity and plasma lipid peroxidation levels before and after metformin induction. There was a significant increase in insulin binding capacity and lipid peroxidation levels in alloxan and STZ diabetes compared to controls. We examined the effect of metformin on alloxan and STZ-induced diabetic rats. In alloxan-induced diabetes metformin (Met) treatment led to an increase in insulin receptor number in liver plasma membranes (before Met: 46.50 +/- 2.69, after Met: 76.00 +/- 3.39 fmol/mg, p < 0.001) and a decrease in plasma lipid peroxidation levels compared to the non-treated group (before Met: 1.85 +/- 0.53, after Met: 1.10 +/- 0.09 nmol MDA/ml, p < 0.05). In STZ-induced diabetic rats metformin treatment did not change the lipid peroxidation levels (before Met: 1.26 +/- 0.31, after Met: 1.38 +/- 0.44 nmol MDA/ml, p > 0.05) whereas it did increase the receptor numbers (before Met: 41.60 +/- 4.33, after Met: 63.40 +/- 8.64 fmol/mg, p < 0.002).

Alloxan↗
PubMed1995

The in vitro effects of captopril on the levels of lipid peroxidation and glutathione of erythrocytes in type II diabetes.

Increase in lipid peroxidation (LP) is an indirect marker of free radical activation. The products of LP (malonyldialdehyde: MDA) are increased in diabetic patients, particularly those with angiopathy. Free radicals are eliminated by cellular enzymes such as superoxide dismutase, catalase and glutathione peroxidase. In this study, the effect and the mechanism of action of captopril, and angiotensin converting enzyme (ACE) inhibitor, on lipid peroxidation in erythrocytes from diabetics was investigated. LP and glutathione were studied in 10 type II diabetics (mean age: 57 +/- 10 yr, duration of diabetes: 12 +/- 6 yr) and in 10 healthy subjects (mean age: 30 +/- 5 yr). Lipid peroxidation levels were 20.69 +/- 4.68 MDA% in diabetics and 9.62 +/- 1.87 MDA% in normal subjects. The LP in erythrocytes of type II diabetics was decreased by the increasing concentrations of captopril (before captopril: 20.69 +/- 4.68, after captopril: (2 x 10(-5) M) 16.68 +/- 7.49 MDA%; (4 x 10(-5) M) 14.17 +/- 7.65 MDA%; (6 x 10(-5) M) 12.33 +/- 2.8 MDA%). No difference was found in the inhibition of LP between the captopril concentrations of 6 x 10(-5) M and 10 x 10(-5) M. After preincubation with captopril, the glutathione level did not change significantly in the diabetic and normal erythrocytes. Preincubation with 2-6 x 10(-5) M captopril showed no effect in the normal group (p > 0.05) but 10 x 10(-5) M captopril reduced lipid peroxidation (p < 0.01). In our study, the high levels of lipid peroxidation in erythrocytes from diabetic patients were decreased after preincubation with captopril. Decrease in the level of lipid peroxidation in vitro was independent of the glutathione level. Crosslink binding between MDA and captopril is suggested.

Adult↗
PubMed1989

[The production of ethyl alcohol in waste sulfite liquor by free and immobilized Candida tropicalis ceppo 571 using batch and continuous systems].

In this study, the free and immobilized cells of Candida tropicalis ceppo 571 yeast were used for the production of ethanol. The yield of ethanol under anaerobic conditions was investigated. Batch technique in flasks and continuous in tubular bioreactor were also applied and the results were compared. It has been shown that the production of ethanol by the free cells was 2.36 times higher than the one by the immobilized cells. The continuous process resulted as the free cells produced ethanol 1.25 times more than the immobilized cells did.

Anaerobiosis↗
PubMed1989

[Single cell protein production and reduction of pollutants in waste sulfite liquor].

In this study, the waste sulphite liquor (W.S.L.) of the Izmit-SEKA factory was tested for its utilization rate in single cell production. The optimum growth requirements of Candida tropicalis ceppo 571 yeast in sulphite liquor medium were examined. 34% and 28.6% reduction in C.O.D. (Chemical Oxygen Demand) and B.O.D. (Biochemical Oxygen Demand) were observed respectively at the end of the growth period. The 2-3% fermentable carbohydrate content of the liquor was converted bio-mass with a rate of 66.6%. The optimum growth yield was reached by the stripping of 25% of the total volume, 30 degrees C, pH: 6.0 conditions.

Biodegradation, Environmental↗