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Biomedical subjects

I Durak

Publications and source records attributed to I Durak.

At least 37 records · Page 2Linked to original sources
PubMed2000

Reduced antioxidant defense capacity in myocardial tissue from guinea pigs treated with 5-fluorouracil.

Antioxidant defense capacity was investigated in myocardial tissue from guinea pigs treated with 5-fluorouracil (5-FU) at a dose of 400 mg/kg/d daily for 5 d administered intraperitonally. Treatment with 5-FU lowered the activities of cardiac superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) accompanied by higher catalase (CAT) activity. Further, antioxidant potential (AOP) values were lower but oxidation resistance (OR) and malondialdehyde (MDA) levels were higher in the 5-FU-treated tissue. With regard to myocardial iron (Fe) and copper (Cu) levels, no significant differences were found between the groups. Results suggest that 5-FU treatment causes impairment in the myocardial antioxidant defense system and leads to cardiac peroxidation. It has been postulated that these changes might be responsible for the 5-FU cardiotoxicity seen in some patients, and antioxidant therapy might provide a therapeutic advantage.

Animals↗
PubMed2000

Erythrocyte oxidant/antioxidant status of diabetic patients.

Present study aims to establish erythrocyte oxidant/antioxidant status in diabetic patients with and without atherosclerotic complications. Fasting blood samples were obtained from 23 diabetic and 12 control subjects. Thirteen patients had no disease other than diabetes mellitus and 10 patients had also atherosclerosis in addition to diabetes mellitus. Erythrocyte antioxidant potential (AOP) and thiobarbituric acid reagent substances (TBARS) levels were measured in these patients and results were compared with those of controls, who were chosen among healthy subjects. Results suggest that although there is an oxidant stress in the erythrocytes of diabetics, this is not due to reduced erythrocyte antioxidant defence potential but, rather, increased free radical production possibly due to hyperglycemia.

Adult↗
PubMed2000

Oxidant/antioxidant status of the erythrocytes from patients with rheumatoid arthritis.

It has been suggested that enzymatic and/or non-enzymatic antioxidant systems are impaired in rheumatoid arthritis (RA) and hence patients are exposed to oxidant stress. This study aimed to establish whether this is really the case. Fasting blood samples were obtained from 24 patients with rheumatoid arthritis and 20 controls. The activities of erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and xanthine oxidase (XO) enzymes and malondialdehyde (MDA), oxidant resistant (OR) and non-enzymatic superoxide radical scavenger activity (NSSA) values were measured in both groups. Patients with RA had higher SOD and XO activities and MDA levels than did the controls. However, NSSA and OR levels were found to be decreased, and CAT and GSH-Px activities unchanged in the study group. Results suggest that excessive free radical production through the xanthine-xanthine oxidase system is the primary factor in rheumatoid arthritis, rather than an impaired antioxidant system. The therapeutic use of XO enzyme inhibitors and some antioxidants can be beneficial in this regard.

Adult↗
PubMed2000

Seminal arginase activity in infertility.

Arginase (Arg) activity in seminal plasma and sperm cells from infertile men and healthy fertile donors was measured. There were no statistically meaningful differences in seminal plasma Arg activity between the two groups whereas sperm cells from oligospermic infertile men had a higher Arg activity compared with the controls. Some important correlations were established between sperm count and Arg activity (negative values) and sperm motility and Arg activity (positive values) in both sperm cells and plasma samples from infertile men. Results suggest that the arginine-nitric oxide pathway within sperm cells from oligospermic infertile men is disturbed by enhanced Arg activity. We think that this may play a part in sperm dysfunction and male infertility.

Adult↗
PubMed2000

Acute effects of smoking of cigarettes with different tar content on plasma oxidant/antioxidant status.

In this study, acute effects of two different types of cigarette smoking on plasma oxidant/antioxidant status were investigated. For this purpose, malondialdehyde (MDA) levels and antioxidant potential (AOP) values were measured in the plasma samples before and after cigarette smoking at fasting. After the first blood sample was obtained, second and third samples were withdrawn at 1.5 h and 3 h. In the first group, subjects smoked five cigarettes with full flavor (FF), and in the second group, five cigarettes with full-flavor low tar (FFLT). Quality classification is made mainly on the basis of tar content of the products. The cigarette with 23 mg tar is defined as FF and that with 12 mg tar as FFLT. MDA level was found to be significantly increased in the 1.5-h plasma samples of both groups, but the increase was greater in the FF group. AOP values, however, were found to be lower in the 3-h plasma samples of both groups, but the decrease was greater in the FF group compared with the FFLT group. It appears that acute smoking causes oxidant stress in blood plasma once exposed to smoke, and then this effect (MDA) begins to decrease. On the other hand, AOP is lowered due to oxidant stress created by smoke. With regard to the types of cigarettes, the FF product seems to be more oxidant than the FFLT product. Our results suggest that antioxidant supplementation might be beneficial for the smokers to cope with the oxidant load derived from cigarette smoke. It is also clearly seen from these results that cigarette manufacturers should reduce tar/nicotine ratio in their products in order to lessen the toxic effects of smoking without causing increased need to smoke.

Adult↗
PubMed2000

Tc-99m polyclonal human immunoglobulin G imaging in Graves' ophthalmopathy.

PURPOSE: The authors evaluated the utility of Tc-99m-labeled human immunglobulin G (HIG) in determining the severity of orbital inflammation and the relation of orbital Tc-99m HIG uptake and clinical parameters in patients with Graves' ophthalmopathy. MATERIALS AND METHODS: Images were obtained in 23 patients (13 women, 10 men; mean age, 51+/-10 years) with Graves' ophthalmopathy. Planar orbital images were obtained and SPECT was performed using a triple-detector gamma camera 4 hours after 370 MBq (10 mCi) Tc-99m HIG injection. Tc-99m HIG uptake was classified using transaxial and coronal slices as 1, mild; 2, moderate; and 3, severe. The clinical severity of orbital disease was categorized, according to the criteria described by Feldon and Unsold, as class I, mild involvement; class II, moderate; and class III, severe. Disease was considered to be clinically inactive if symptoms and signs were stable or improved in the last two examinations performed at least 6 months apart. RESULTS: Sixteen patients were clinically inactive, and seven patients were active. The mean Tc-99m HIG classes were 1.5+/-0.5 and 2.6+/-0.5, respectively (P = 0.02). There was not a good correlation between the clinical classification and Tc-99m HIG classification, whereas the presence of active disease showed a good correlation with Tc-99m HIG classification (r = 0.703; P = 0.0002). CONCLUSIONS: Tc-99m HIG imaging showed possible ongoing subclinical inflammation in the orbits of the patients with Graves' ophthalmopathy regardless of the clinical classification. Tc-99m HIG SPECT seems a promising procedure for evaluating the presence of active orbital inflammation.

Female↗
PubMed2000

An unusual central retinal dystrophy associated with ichthyosis vulgaris.

A number of ichthyosis syndromes may have retinal abnormalities such as the retinitis pigmentosa-like diffuse rod-cone dystrophy in Refsum's syndrome and the maculopathy in Sjögren-Larsson syndrome. We present two sisters who have an unusual, almost identical, bilaterally symmetric central retinal dystrophy associated with ichthyosis vulgaris in the absence of other systemic disorders. We believe that this dystrophy has not been previously described in patients with any of the known varieties of ichthyosis.

Adolescent↗
PubMed1999

High-temperature effects on antioxidant systems and toxic product formation in nutritional oils.

In this study, effects of high-temperature heating on antioxidant defense potential (AOP) and malondialdehyde (MDA) levels were investigated in several types of oils ingested by humans. Natural olive oil, refined olive oil, sunflower oil, and soy oil were examined. High-temperature heating to 180 degrees C significantly decreased AOP. This was accompanied by a significant increase in MDA levels. The observed changes were quantitatively greater in soy and sunflower oil compared to olive oil. The loss in antioxidant defense potential and elevation in peroxidation products may be associated with enhanced disease processes.

Animals↗
PubMed1999

Effects of smoking on plasma and erythrocyte antioxidant defense systems.

In this study, activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) enzymes were measured in the erythrocytes, and levels of thiobarbituric acid-reactive substances (TBARS) and antioxidant potential (AOP) values were measured in both erythrocyte and plasma samples from smokerS and nonsmokers. No significant differences were observed in erythrocyte parameters, serum triglycerides, and total cholesterol. AOP was significantly lower and TBARS level higher in the plasma samples from smokers compared with those of nonsmokers. Results suggest that smoking causes no impairment in the enzymatic antioxidant defense system and does not lead to oxidant stress in the erythrocytes, possibly because these cells have potent antioxidant defense capacity.

Adult↗
PubMed1999

Isoflurane impairs antioxidant defence system in guinea pig kidney.

PURPOSE: To investigate whether free radical metabolism is changed due to isoflurane treatment and, if so, to elucidate the role of changed free radical metabolism in the nephrotoxicity. MATERIALS AND METHODS: Fifteen guinea pigs were used in the study. Five were treated with isoflurane in oxygen, five with oxygen and five were controls. Animals were exposed to isoflurane and oxygen three times. Each treatment was performed for 30 min once a day for three consecutive days. Activities of free radical enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px); values of antioxidant parameters, antioxidant potential (AOP), non-enzymatic superoxide radical scavenger activity (NSSA) and oxidation resistance (OR) and, level of an oxidant parameter namely, malondialdehyde (MDA) were determined in the renal tissues of the groups. Blood was also obtained for serum creatinine and urea analyses. RESULTS: AOP, NSSA, SOD and CAT activities were decreased; (0.0188 +/- 0.0026 vs 0.0156 +/- 0.0015, P < 0.025; 8.72 +/- 1.80 vs 6.40 +/- 1.22, P < 0.05; 76.71 +/- 18.54 vs 52.79 +/- 11.68, P < 0.025; 71.26 +/- 15.58 vs 55.39 +/- 8.83; P < 0.05, respectively) but, MDA level, OR value and GSH-Px activities increased (10.89 +/- 1.57 vs 15.87 +/- 2.97, P < 0.01; 0.84 +/- 0.34 vs 2.28 +/- 1.39, P < 0.05; 1.45 +/- 0.83 vs 3.45 +/- 1.20, P < 0.01, respectively) in kidney tissues from isoflurane-treated group compared with controls. No differences were observed between control and oxygen groups with regard to all analysis parameters except GSH-Px. CONCLUSION: Isoflurane impairs the antioxidant defence system and this oxidant stress may play a part in the isoflurane-induced renal toxicity.

Anesthetics, Inhalation↗
PubMed1999

Oxidant/antioxidant status of plasma samples from patients with rheumatoid arthritis.

This study aims to elucidate plasma oxidant/antioxidant status in patients with rheumatoid arthritis (RA). Fasting blood samples were obtained from 24 patients with RA and 20 control subjects. Antioxidant potential (AOP) value, nonenzymatic superoxide radical scavenger activity (NSSA), and malondialdehyde (MDA) levels were measured to establish plasma oxidant/antioxidant status in the patient and control groups. Patients with RA had lower AOP and NSSA but higher MDA levels than those of the control subjects, which was an indication of reduced antioxidant capacity and oxidant stress in these patients. Results suggest that the antioxidant system is impaired and peroxidation reactions are accelerated in patients with RA. We suppose that therapeutic use of some antioxidants may be beneficial in this regard.

Adult↗
PubMed1999

Pre-Descemet's membrane hemorrhage after secondary intraocular lens implantation.

A 6.0 x 4.0 mm pre-Descemet's membrane hemorrhage with very sharp borders appeared at the temporal portion of the cornea. There was no hyphema in the anterior chamber on the first day after secondary intraocular lens implantation. The hemorrhage resolved almost totally in 1 year without intervention, leaving slight, deep pigmentary changes and minimal diffuse corneal edema.

Corneal Diseases↗
PubMed1999

The effect of red wine on blood antioxidant potential.

We investigated the effects of red wine on blood antioxidant potential in an attempt to elucidate molecular mechanisms concerning the possible protective role of red wine in atherosclerosis. Volunteer subjects in the study group consumed a standard meal and drank red wine (5 mg/kg) while controls consumed the same meal and drank water. Over 4 1/2 hours, blood samples were taken, and malondialdehyde (MDA) and antioxidant potential (AOP, obtained from MDA levels before and after superoxide radical attack) values were measured in the plasma and erythrocytes. We found that AOP values of plasma and erythrocyte samples from the study group were at their highest after 1 1/2 hours and then declined to basal values at 4 1/2 hours. There were no statistically significant differences between the basal AOP values of the study group and the control group. With regard to MDA levels, gradual increases were seen in the plasma of the control group during the 3 hours after food, but no changes were seen in the plasma of the study group in this period. Although there were increases in erythrocyte MDA levels of both groups over 3 hours, the MDA production rate was significantly higher in the control group. Our results suggest that red wine causes significant increases in AOP values of plasma and erythrocytes, which may prevent cellular peroxidation reactions and lessen atherosclerotic complications through inhibition of LDL.

Adult↗
PubMed1999

Comparison of antioxidant potentials of red wine, white wine, grape juice and alcohol.

Antioxidant potential (AOP) and non-enzymatic superoxide radical scavenger activity (NSSA) values of red wine, white wine, grape juice and ethyl alcohol were assessed and values were compared. The effects of these beverages on serum AOP and NSSA values were also measured in vitro. Red wine, white wine and grape juice exert strong antioxidant activity in similar degrees and all produce significant effects on serum AOP and NSSA values. However, ethyl alcohol does not have either AOP or NSSA, nor does it have an effect on serum AOP or NSSA values. AOP values (nmol/ml h) of red wine, white wine and grape juice were 20.8 +/- 4.2, 23.2 +/- 4.0 and 24.6 +/- 4.8, respectively. NSSA values (U/ml) of red wine, white wine and grape juice were 30.4 +/- 6.8, 26.8 +/- 5.6 and 32.6 +/- 5.8, respectively. There were no statistically meaningful differences between AOP and NSSA values of the groups (p > 0.05 for all). Results suggest that red wine, white wine and grape juice all have high antioxidant potential to protect cellular structures against peroxidation reaction owing to their rich phenolic contents.

Analysis of Variance↗