Ibrahim Kocer

Protective role of intramuscularly administered vitamin E on the levels of lipid peroxidation and the activities of antioxidant enzymes in the lens of rats made cataractous with gamma-irradiation.

Purpose To determine the antioxidant role of vitamin E (VE) (10 mg/kg/day) against radiation-induced cataract in lens after total-cranium irradiation of rats with a single dose of 5 Gy. Methods Sprague-Dawley rats were divided into three groups. Group 1 did not receive VE or irradiation but received both 0.1 ml physiologic saline intraperitoneally and sham irradiation (control group). Group 2 received to total cranium 5 Gy of gamma irradiation as a single dose (RT group) plus 0.1 ml physiologic saline intraperitoneally. Group 3 received irradiation to total cranium plus 10 mg/kg/day VE (RT+VE group). The rats were irradiated using a cobalt-60 teletherapy unit. Chylacks cataract classification (1) was used in this study. At the end of 10 days, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes (the activity of superoxide dismutase [SOD], glutathione peroxidase [GSH-Px]) and lipid peroxidation level (malondialdehyde [MDA]). Results While grade 1 cataract development was detectable in seven rats in the RT group, it was detectable only in two rats in the RT+VE group, whereas none of the rats in the control group exhibited any biomicroscopic change in their lenses. MDA level and GSH-Px activity in the rat lens in the RT group was significantly higher than in the control group. SOD activity in the RT group was lower than in the control group. The activity of SOD and GSH-Px enzymes was higher in the RT+VE group, but MDA level was lower in the RT+VE group when compared with the RT group. Conclusions Vitamin E has a protective effect on radiation-induced cataract by decreasing oxidative stress.

Oxidative DNA damage in patients with cataract

Acta Ophthalmol. 2010: 88: 891–895

Effects of Oral Ginkgo biloba Supplementation on Cataract Formation and Oxidative Stress Occurring in Lenses of Rats Exposed to Total Cranium Radiotherapy

PurposeTo determine the antioxidant role of Ginkgo biloba (GB) in preventing radiation-induced cataracts in the lens after total-cranium irradiation of rats with a single radiation dose of 5 Gy.MethodsSprague-Dawley rats were randomly divided into three groups. Group 1 received neither GB nor irradiation (control group). Group 2 was exposed to total-cranium irradiation of 5 Gy in a single dose [radiation therapy (RT) Group], and group 3 received total cranium irradiation from a cobalt-60 teletherapy unit, plus 40 mg/kg per day GB (RT+GB group). At the end of the tenth day, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the lipid peroxidation level [malondialdehyde (MDA)].ResultsIrradiation significantly increased both the MDA level and the activity of GSH-Px, and significantly decreased the activity of SOD in the rat lenses. GB supplementation significantly increased the activities of SOD and GSH-Px enzymes and significantly decreased the MDA level. Total cranium irradiation of 5 Gy in a single dose promoted cataract formation, and GB supplementation protected the lenses from radiation-induced cataracts.ConclusionsWe suggest that Ginkgo biloba is an antioxidant that protects the rat lens from radiation-induced cataracts.

Oxidative DNA damage in retinopathy of prematurity

Purpose This study examines the levels of oxidative damage in patients with retinopathy of prematurity (ROP). Methods Fifty patients were recruited with a birthweight below 1500 g or gestational age below 32 weeks. The cases were classified into those who developed ROP (n=25) and those without ROP (n=25). The authors obtained blood and urine samples from each infant, for measuring 8-hydroxy 2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) levels, at the time of the first examination at 4–6 postnatal weeks. Results A significant difference was observed in leukocyte and urine 8-OHdG levels in patients with ROP compared to those without ROP (p<0.001 for both). Similarly, a significant difference was observed in plasma and urine MDA levels in patients with ROP compared to those without ROP (p<0.001 for both). In addition, significant correlations were found between levels of 8-OHdG in leukocyte DNA and plasma MDA (r=0.859, p<0.001), and between levels of urine 8-OHdG excretion and urine MDA (r=0.563, p<0.001). Conclusions 8-OHdG in leukocyte DNA and urine levels in premature infants can be useful as an indicator for ROP screening.

EFFECT OF ACUTE SUBMAXIMAL EXERCISE ON INTRAOCULAR PRESSURE IN ATHLETES AND SEDENTARY SUBJECTS

The existing literature is controversial regarding the relationship between physical fitness and intraocular pressure (IOP). Therefore, the effects of acute submaximal exercise on IOP were compared in athletes and sedentary subjects. Acute exercise increased IOP in male athletes, but had no effect in sedentary men. Also, it decreased IOP in sedentary women, but had no effect in female athletes. Sex and physical fitness both were significant factors influencing the changes in IOP due to exercise. These results suggest that acute dynamic exercise is useful to decrease IOP in sedentary women, but not in male athletes. These results may help glaucoma screeners.

Protection of the retina from ischemia-reperfusion injury by L-carnitine in guinea pigs.

Purpose To investigate the efficacy of L-carnitine in preventing retinal injury followed by ischemia-reperfusion. Methods The eyes of 34 guinea pigs were used in this experiment. The guinea pigs were divided into two groups: the first group (n= 17) was given L-carnitine intraperitoneally (500mg/kg) and second group (n=17) received the same dose of saline solution. Under general anesthesia, peritomy was performed. Retro-orbital tissues were ligated for 90 minutes and ischemia was induced, followed by 4 hours of reperfusion. One of the enucleated eye was stained with hematoxylin and eosin (H&E) and retinal thicknesses were evaluated. Thiobarbituric acid reactive substances (TBARS) levels were determined in the retina of the other eye. Results Mean TBARS levels in retinal tissue were found lower in L-carnitine group (2.77 ± 0.55 μM) than in the control group (6.57 ± 1.19 μM), (p<0.01). On the other hand, mean retinal thickness was found to be increased in the control group (47.47 ± 5.62 μm) when compared to the L-carnitine group (26.52 ± 4.65 μm), (p<0.01). In correlation analysis, significantly positive relationships were found between retinal TBARS level and retinal thickness both in the control and L-carnitine groups (r=0.981, p<0.01 and r= 0.967, p<0.01 respectively). Conclusions. L-carnitine is effective in preventing retinal injury followed by ischemia-reperfusion.

Pseudotumor Cerebri Secondary to Subacute Sclerosing Panencephalitis

Pseudotumor cerebri is characterized by signs of raised intracranial pressure occurring in the absence of obvious brain pathology. We present an 8-year-old boy with pseudotumor cerebri secondary to subacute sclerosing panencephalitis. The reported patient suggests a possible association between subacute sclerosing panencephalitis and pseudotumor cerebri and that subacute sclerosing panencephalitis should be added to the list of disorders known to be associated with pseudotumor cerebri. Patients with subacute sclerosing panencephalitis might benefit from treatment aimed at increased intracranial pressure. (J Child Neurol 2004;19:627-629).

LONG-TERM EFFECTS OF MILD EXERCISE ON INTRAOCULAR PRESSURE IN ATHLETES AND SEDENTARY SUBJECTS

The long-term effects of acute submaximal exercise on intraocular pressures (IOPs) of right-and left-eyes and recovery times to basement levels of IOP in postexercise periods in sedentary and physically fit subjects were investigated. Twenty-five sedentary and 24 physically fit subjects, ranging in age 17 to 22 years, participated. Intraocular pressures were measured by a pneumotonometer. Measurements were taken in the morning at about nine (at rest) and immediately, 30 min and 2 h after acute submaximal exercise. In sedentary subjects, IOPs of both right- and left-eyes decreased immediate after exercise, but, these decreases in both eyes continued 30 min and 2 h after exercise. In physically fit subjects, IOPs of both right- and left-eyes increased immediate after exercise, but decreased after 30 min exercise compared to basement levels, and this decrease continued 2 h after exercise. Acute submaximal exercise decreased IOPs of right and left eyes over a period 2 h in sedentary and physically fit subjects. IOP reducing after exercise was different between right- and left-eyes in sedentary subjects. These results suggest that exercise can be used in ocular hypertension treatment.

Agmatine as retinal protection from ischemia-reperfusion injury in guinea pigs

PurposeTo determine the neuroprotective effect of agmatine (Agm) on the retinas of guinea pigs subjected to a transient ischemia-reperfusion insult.MethodsTwenty-eight guinea pigs were randomly divided into four groups. Forty-five minutes before ischemic insult, the guinea pigs were intraperitoneally administered either Agm (50 mg/kg) (Agm 1) or saline (control 1 group) once, or twice separated by a 12-h interval (Agm 2; control 2). Transient ocular ischemia was achieved under general anesthesia by cannulating an anterior chamber maintainer connected to an infusion line of a semiflexible bottle. The saline reservoir pressure was increased by using a blood pressure tolls cuff to achieve an intraocular pressure (IOP) of 150 mmHg. This IOP was maintained for 90 min. Reperfusion was achieved by pulling off the anterior chamber maintainer. The animals in the Agm 1 and control 1 groups were killed at the end of the 4-h reperfusion period. The eyes were enucleated for histopathological (retinal thickness) and biochemical (thiobarbituric acid reactive substance, TBARS, and nitric oxide, NO) investigation. The animals in the Agm 2 and control 2 groups were killed at the end of a 24-h reperfusion period.ResultsThe mean retinal thickness of the animals in the Agm 1 (25.94 ± 1.23 μm) and Agm 2 (24.49 ± 0.88 μm) groups was lower than that of those in the control 1 (37.60 ± 2.27 μm) and control 2 (36. 64 ± 1.32 μm) groups (P < 0.05). The mean TBARS level of the animals in the Agm 1 (8.37 ± 0.94 nmol/ml) and Agm 2 (8.01 ± 0.97 nmol/ml) groups was lower than that of those in the control 1 (12.09 ± 1.27 nmol/ml) and control 2 (12.09 ± 1.27 and 11.72 ± 1.63 nmol/ml) groups (P < 0.05). The mean NO level of the animals in the Agm 1 (100.77 ± 6.20 nmol/ml) and Agm 2 (94.63 ± 5.24 nmol/ml) was lower than that of those in the control 1 (131.77 ± 4.61 nmol/ml) and control 2 (122.43 ± 4.35 nmol/ml) groups (P < 0.05). There were positive correlations between the TBARS and NO levels and retinal thickness in the Agm and control groups.ConclusionAgmatine exerts a significant neuroprotective effect on guinea pig retinas after transient ischemia-reperfusion insult.

Diabetic cataract and the total antioxidant status in aqueous humor.

Abstract Some mechanisms have been proposed for cataract formation in diabetes mellitus such as excessive tissue sorbitol concentrations, abnormal glycosylation of lens proteins and increased free radical production in the intraocular region. We measured total antioxidant status and uric acid levels in aqueous humor from diabetic (n=20) and non-diabetic subjects (n=16) with cataracts. The patients with diabetes and cataract had significantly lower aqueous humor total antioxidant status than those with senile cataract (p = 0.001). Serum and aqueous humor uric acid levels were significantly lower in the diabetic cataract group compared to the senile cataract group. In the diabetic cataract group, the aqueous humor antioxidant status correlated positively with the aqueous humor uric acid levels (p < 0.05). The results of this study suggest that reduced aqueous humor antioxidant status might be associated with reduced aqueous humor uric acid in patients with diabetic cataract. This decrease in aqueous humor uric acid levels might lead to the acceleration of cataract formation.