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Biomedical subjects

G Yilmaz

Publications and source records attributed to G Yilmaz.

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

Elevated vitreous nitric oxide levels in patients with proliferative diabetic retinopathy.

PURPOSE: The aim of this study was to determine nitric oxide levels in the vitreous of patients with proliferative diabetic retinopathy. METHODS: Using the spectrophotometric method based on Griess reaction, we measured levels of nitrite, the stable product of nitric oxide, in the vitreous of 21 eyes of 21 patients who underwent vitrectomy for the treatment of proliferative diabetic retinopathy with tractional retinal detachment, prospectively. Three samples were excluded from the study because of blood contamination. The control group was made up of vitreous samples from 15 eyes of 15 normal cadavers and five eyes of five patients who were undergoing vitrectomy for macular hole surgery. RESULTS: Nitrite levels were 0. 524 +/- 0.27 microM and 0.383 +/- 0.17 microM in the vitreous of patients with proliferative diabetic retinopathy of diabetes type I and type II, respectively. In 15 cadaver eyes and five vitreous samples from patients who underwent macular hole surgery, nitrite levels were below the detection limit (less than 0.08 microM). There was no significant difference between nitrite levels in patients with type I and type II diabetes (P =.56), whereas there was a significant difference between diabetes groups and controls (P <. 00001). CONCLUSION: Vitreous nitric oxide levels are elevated in patients with proliferative diabetic retinopathy with tractional retinal detachment. Nitric oxide may play a role in the pathogenesis of proliferative diabetic retinopathy.

Adult↗
PubMed2000

Macular ischaemia in Behçet's disease.

PURPOSE: To report macular ischaemia and visual loss in patients with panuveitis due to Behçet's disease. METHODS: We describe macular ischaemia, a rare finding, in 3 eyes of 3 patients with panuveitis who were diagnosed and treated as having Behçet's disease. The patients underwent fundus fluorescein angiography (FFA) using a digital imaging system and were treated with topical and oral steroids and cyclosporine in 2 cases, and with added azathioprine in the third case. RESULTS: The 3 eyes showed macular ischaemia associated with peripheral retinal vasculitis on FFA and control of inflammation was achieved in all cases. After an average of 2 years follow-up, visual acuity and macular ischaemia improved in 2 eyes, while no recovery was seen in the third. CONCLUSION: The presence of macular ischaemia on FFA in Behçet's disease is a predictor of poor visual outcome. Macular ischaemia may show partial recovery with the treatment of the disease.

Adult↗
PubMed2000

Effect of nitric oxide on proliferation of human retina pigment epithelial cells.

PURPOSE: To investigate the effects of exogenous and endogenous nitric oxide (NO) on the proliferation of human retina pigment epithelial (RPE) cells. METHODS: We stimulated cultured human RPE cells with 3-morphosydnonimine (SIN-1) to analyse the effect of exogenous NO. Incubation with a cytokine cocktail (interleukin 1-beta + interferon gamma + tumour necrosis factor alpha) plus lipopolysaccharide (LPS) induced cells to synthesise NO endogenously. The cultures were then incubated for 48 h, after which the cells were stained with crystal violet and absorbance at 550 nm was measured spectrophotometrically. RESULTS: SIN-1 inhibited human RPE cell proliferation, while haemoglobin, an NO inhibitor, almost completely blocked the inhibitory effect. On the other hand, treatment with the cytokine cocktail plus LPS did not inhibit RPE cell proliferation. CONCLUSION: These findings confirm that exogenous NO inhibits human RPE cell proliferation, while endogenous NO has no such blocking effect.

Cell Division↗
PubMed2000

Evaluation by exercise testing of children with mild and moderate valvular aortic stenosis.

BACKGROUND: The aim of the present paper was to determine the factors related to sudden death in aortic stenosis. METHODS: The factors related to sudden death were investigated in 40 asymptomatic children with mild and moderate aortic stenosis by treadmill testing. RESULTS: The QT interval of aortic stenosis cases were significantly longer than those of healthy children with increasing heart rates during exercise. CONCLUSIONS: A longer QT interval of aortic stenosis cases compared to normal children during exercise is the first sign of myocardial ischemia and leads to fatal ventricular arrhythmias and sudden death. For this reason we recommend that exercise testing should be performed frequently in aortic stenosis patients and that close follow up is necessary for patients with long QT segments that can be a marker for severe arrhythmias.

Adolescent↗
PubMed2000

Aqueous humor nitric oxide levels in patients with central retinal artery occlusion.

BACKGROUND/PURPOSE: There is increasing evidence suggesting that nitric oxide (NO) is implicated in the pathogenic process of ischemic disease. The purpose of this study was to quantify the aqueous humor NO levels in patients with central retinal artery occlusion (CRAO) and in age-matched controls. METHODS: Aqueous humor specimens were obtained from seven patients who had been diagnosed with CRAO; the sampling was done within 12 to 24 hours of diagnosis. All specimens were obtained by paracentesis, which was performed as a therapeutic intervention. Samples of aqueous humor were also collected from 15 age-matched healthy patients undergoing cataract surgery, to be used as controls. For each sample, we assayed the amount of nitrite, which is the stable metabolite of NO, using the spectrophotometric method based on the Griess reaction. RESULTS: There were detectable levels of nitrite in the aqueous humor from five of seven patients with CRAO (mean level, 0.32 +/- 0.08 micromol/L). The levels in the control group were below the detection limit in all cases (<0.08 micromol/L). There was a statistically significant difference between the aqueous humor nitrite levels in the CRAO group and the controls (P = 0.0008). CONCLUSIONS: Our study shows that patients with CRAO present with elevated levels of NO in the aqueous humor. These findings may provide insight into the role that NO plays in CRAO.

Aged↗
PubMed2000

Disulfonic stilbene prevents selenite-induced cataract in rat pup lens.

It is known that the subcutaneous injection of a single dose of sodium selenite into suckling rats results in the development of large nuclear opacities. The intracellular transport of selenite in various cells, except lens cells, occurs via the Cl/HCO3 exchanger. The aim of the present study is to investigate the possible role of the anion-exchange inhibitor, disulfonic stilbene (SITS), in the selenite-induced catarogenesis in the rat pups. Wistar albino rats (8-10 d old) were separated into three groups: one control and two experimental. The first experimental group was injected subcutaneously with a single dose of 30 nmol sodium selenite/g body weight. The second experimental group was injected with a single dose of 10 nmol SITS/g body weight 15 min before the same dose selenite injection. The control group did not have any injections. The stage of cataract development was examined on d 7 postinjection with slit-lamp photographs. In SITS pretreated group, all eyes remained transparent (considered as stage 0), whereas in the selenite-injected group, the animals did have different stage of nuclear cataract; 8 animals have stage 5, 10 animals have stage 4, and 4 animals have stage 3. A pretreatment of SITS completely prevented cataract formation of the selenite-induced cataract model in rat pups.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed2000

Optic disk neovascularization in a patient with cytomegalovirus retinitis associated with renal transplantation.

PURPOSE: To report the development of optic nerve head neovascularization during the recovery phase of cytomegalovirus (CMV) retinitis in a renal allograft recipient. CASE REPORT: A 46-year-old male renal allograft recipient developed CMV retinitis seven months after transplantation. At the time of the diagnosis, the patient was being immunosuppressed with prednisone, cyclosporine, and azathioprine, and was treated with repeated intravitreal and intravenous ganciclovir. Six weeks after the initiation of therapy, optic disk neovascularization developed. This was confirmed by fluorescein angiography, which showed no areas of retinal capillary nonperfusion. At this stage, active retinal lesions were partially resolved. Apart from intraocular inflammation, no other cause of neovascularization was detected. Over the following six months, optic disk neovascularization regressed spontaneously without causing vitreous hemorrhage or visual loss. There was no recurrence of CMV retinitis during follow-up. CONCLUSION: Optic disk neovascularization may develop in the healing phase of CMV retinitis in renal transplant recipients.

Cytomegalovirus Infections↗
PubMed2000

Prevention of selenite-induced opacification and biochemical changes in the rat pup lens through amiloride pretreatment.

PURPOSE: To determine the effects of amiloride on selenite-induced cataracts, to identify this agent's role as an anti-oxidant, and to study related effects on ion levels in the rat lens. METHODS: Wistar albino rat pups were assigned to one of three groups, one control and two experimental. The first experimental group (Group 1; n = 22) received a subcutaneous injection of sodium selenite (30 nmol/g body weight) on postpartum day 10. The second experimental group (Group 2; n = 21) received a subcutaneous injection of amiloride (1 nmol/g body weight) 15 minutes before the sodium selenite injection. The control group (n = 22) received no injection. The pups in each group were observed during three weeks after the injection date. At the end of this period, the stage of cataract development was identified by comparison with slit lamp photographs and then the pups were sacrificed and their lenses were removed intracapsularly using a posterior approach. Cation analysis was carried out and glutathione and malondialdehyde levels were measured for each group. RESULTS: Cataract stage in Group 1 was significantly higher than Group 2. Mean cataract stages in Groups 1 and 2 were 3.8+/-0.12 and 1.6+/-0.25 respectively. None of the control animals developed cataracts. Amiloride-pretreated group contained significantly higher glutathione levels than Group 1. The level of malondialdehyde in Group 1 lenses was approximately twice that in the lenses of the Group 2 amiloride+selenite-treated animals. The Ca(2+) level was significantly higher in Group 1 lenses compared to the amiloride-pretreated rats, but there was no significant difference between Groups 1 and 2 with regard to Na(+) and K(+) levels. CONCLUSION: Amiloride was very effective in preventing cataract formation in the selenite-induced cataract model. This protective effect of amiloride was accompanied by higher glutathione levels and lower malondialdehyde levels in the rat pups' lenses compared to levels in animals that received selenite alone. These results suggest an anti-oxidant role for this agent, in addition to its effects on lens ion homeostasis.

Amiloride↗
PubMed2000

[Granulomatous peritonitis due to Ascaris lumbricoides].

Ascaris lumbricoides is one of the most common and most widespread helminthic infections of humans. Infection with ascaris appears to be asymptomatic in the vast majority of cases, but may produce serious pulmonary disease or obstruction of biliary or intestinal tract in a small proportion of infected people. We examined under the light of literature this case which caused the granulomatous peritonitis by ascaris, the adult worm, without any evidence of intestinal perforation.

Adult↗
PubMed1999

Helicobacter pylori antibodies in hemodialysis patients and renal transplant recipients.

In this cross-sectional, controlled study, Helicobacter pylori (H. pylori) infection, a probable factor in the development of gastrointestinal problems, was investigated in dialysis patients and renal transplant recipients. Forty-seven dialysis patients (22 male, 25 female, mean age of 36.6 +/- 15 yr (range 18-83 yr)), 57 renal transplant recipients (39 male, 18 female, mean age of 36.8 +/- 10 yr (range 19-60 yr)) and 55 healthy individuals (34 male, 21 female, mean age of 33.4 +/- 9.6 yr (range 21-58 yr)) were included and no significant difference was found in the study groups. The mean time spent on dialysis in the hemodialysis group was 32.5 +/- 27.7 months (range 1-100 months). H. pylori antibodies were detected in 22 of 57 (38.6%) patients in the transplantation group, 31 of 47 (65.9%) patients in the dialysis group and 39 of 55 (72.5%) in the control group. No correlation was found between H. pylori infection and age, sex, primary disease, frequency of dialysis, duration and type of transplantation and the immunosuppressive therapy. However, patients with H. pylori antibodies spent a shorter time on dialysis compared to patients without the antibodies (26.6 +/- 23.5 vs 44.1 +/- 32.1 months, p = 0.038). The frequency of H. pylori infection in the transplantation group was significantly lower than the control and dialysis groups (p < 0.01). This finding may be explained on the basis of decreased humoral antibody response to H. pylori infection, secondary to immunosuppressive therapy rather than decreased incidence of infection in the transplantation group. Finally, we concluded that the value of the serological test for diagnosis of H. pylori infection should be interpreted cautiously in these patient groups.

Adolescent↗
PubMed1999

Malnutrition and growth failure in cyanotic and acyanotic congenital heart disease with and without pulmonary hypertension.

AIM: To investigate the effect of several types of congenital heart disease (CHD) on nutrition and growth. PATIENTS AND METHODS: The prevalence of malnutrition and growth failure was investigated in 89 patients with CHD aged 1-45 months. They were grouped according to cardiac diagnosis: group aP (n = 26), acyanotic patients with pulmonary hypertension; group ap (n = 5), acyanotic patients without pulmonary hypertension; group cp (n = 42), cyanotic patients without pulmonary hypertension; and group cP (n = 16), cyanotic patients with pulmonary hypertension. Information on socioeconomic level, parental education status, birth weight and nutrition history, number of siblings, and the timing, quality, and quantity of nutrients ingested during weaning period and at the time of the examination were obtained through interviews with parents. RESULTS: There was no significant difference between groups in terms of parental education status, socioeconomic level, duration of breast feeding, and number of siblings (p > 0.05). Group cP patients ingested fewer nutrients for their age compared to other groups. 37 of the 89 patients were below the 5th centile for both weight and length, and 58 of 89 patients were below the 5th centile for weight. Mild or borderline malnutrition was more common in group aP patients. Most group cp patients were in normal nutritional state, and stunting was more common than wasting. Both moderate to severe malnutrition and failure to thrive were more common in group cP patients. CONCLUSION: Patients with CHD are prone to malnutrition and growth failure. Pulmonary hypertension appears to be the most important factor, and cyanotic patients with pulmonary hypertension are the ones most severely affected. This study shows the additive effects of hypoxia and pulmonary hypertension on nutrition and growth of children with CHD.

Child, Preschool↗
PubMed1998

The effect of selenium and vitamin E on microvascular permeability of rat organs.

The effects of dietary sodium selenite and vitamin E on the microvascular permeability of rat organs such as heart, brain, kidney, liver and eye were investigated by using the Evans blue leakage method. Combined deficiency of selenium and vitamin E caused an increase in the permeability of the heart and eye with respect to their controls while it had no considerable effect on the permeability of other organs. On the other hand, toxic levels of selenium (4.2 mg/kg) in diet decreased the permeabilities in kidney, liver, and eye whereas this parameter of brain increased in the same animal group. These results suggested that low or high sodium selenite and vitamin E contents in diet could alter the microvascular permeability of different organs in different manners. It might be important to give reasonable explanations for the pathophysiology of some diseases that are characterized with organ damage and/or disfunction originated from selenium deficiency or toxicity.

Animals↗