Role of anti-oxidant enzymes superoxide dismutase and catalase in the development of cataract : study of serum levels in patients with senile and diabetic cataracts.

Cataract is a universal phenomenon in old age and the most common cause of blindness worldover. Oxidative stress is believed to be a key factor in the gradual loss of transparency of lens. Free radicals formed result in derangement and opacification of lens fibres. Superoxide dismutase, catalase and glutathione peroxidase are major anti-oxidant enzymes, which protect against free radicals. The purpose of this study is to evaluate the role of anti-oxidant enzymes - superoxide dismutase and catalase in the development of cataract in senile and diabetic persons. Serum levels of major anti-oxidant enzymes-superoxide dismutase and catalase were estimated in 20 patients with diabetic cataract, and matched with another 20 patients of senile cataract taken as control. Estimation of superoxide dismutase was done by improved spectrophotometric assay based on epinephrine auto-oxidation at 480nm, while catalase estimation was done by the method of Hugo Aebi. The mean serum levels of superoxide dismutase and catalase were lower as age increased. These enzymes were also significantly lower in diabetic cataracts (9.13 and 16.42 units/ml) as compared to senile cataracts (25.30 and 57.27units/ml). Oxidative stress is one of the major factors contributing to cataract formation. In diabetics where there is increased oxidative stress, the serum levels of the major anti-oxidant enzymes decrease, which lead to early cataract formation. It may be concluded that oxidative stress is an important factor in the development of diabetic cataracts and anti-oxidants may have a role in decreasing the incidence of cataract.

Amniotic membrane transplantation in ocular surface disorders.

In this prospective study, 81 eyes of 70 patients diagnosed with various ocular surface disorders were enrolled to document the use of amniotic membrane transplantation in various ocular surface disorders. Detailed history and ocular examination was done. Ocular photographs and consent from all patients were taken. Fluorescein staining and impression cytology was done preoperatively and postoperatively in selected cases. Amniotic membrane was prepared from the placenta of a donor (consent taken and negative for infectious disorders), after separating amnion from chorion. It was washed with antibiotic solutions, transferred over nitrocellulose paper and stored in Dulbecco's modified Eagle's minimum essential medium at -80 degrees C. Recipient bed was prepared by removing the fibrovascular pannus and necrosed conjunctiva. Amniotic membrane was transplanted with the epithelial side up and sutured. Sixty-four eyes had good result by clinical evaluation or impression cytology findings, 5 eyes later required limbal stem cell culture and transplantation. All the 3 eyes had failure of the fornix reconstruction and 5 eyes had recurrence of the pterygium. Amniotic membrane provides lower recurrence rate in cases of recurrent pterygium. Alkali injuries are more dangerous but showed good response to amniotic membrane transplantation combined with limbal autografting or ex-vivo expansion and later transfer. Initial proper assessment of limbal involvement, conjunctival necrosis and corneal involvement is the key to the management of acute cases. Contracted sockets showed no improvement. Shield ulcers and persistent epithelial defect and ocular surface defects secondary to tumour excision showed excellent results.

Audiometric and vestibular abnormalities in macular degeneration.

Audiometric (pure tone audiometry and tone decay) and vestibular examinations (bilateral caloric test and electronystagmography) were carried out in 10 cases of macular degeneration of different types and 10 normal individuals as control. Out of 10 cases of macular degeneration of various types, 3 (30%) showed hearing impairment, while on vestibular examination 3 (30%) also had vestibular abnormalities. Only one case was associated with both audiometric as well as vestibular abnormalities. In the control group none of the individual showed either audiometric or vestibular changes.

Embryonal rhabdomyosarcoma of orbit--a case report.

Embryonal rhabdomyosarcoma of orbit presenting as a case of rapid proptosis of the right eye is reported in a 4 year old male child. There was no evidence of recurrence during a follow up of 6 months. Rhabdomyosarcoma is one of the most common primary malignant orbital neoplasms of child hood. It usually produces a precipitously progressing unilateral proptosis of sudden onset. It is a highly malignant neoplasm of pleuripotential embryonic mesoderm, which commonly differentiates to form cells similar to rhabdomyoblasts of the foetus. Because of the presence of elongated cells that contain abundance of eosinophilic glycogen rich cytoplasm, it is generally referred to as embryonal form of rhabdomyosarcoma.

Tuberculoma of the orbit--a case report.

A case of orbital tuberculoma presenting with proptosis and gross diminution of vision in a young girl 20 years is reported. The tuberculoma disappeared within 3 months of antitubercular therapy and there was marked improvement in visual acuity. Because of its rarity in the younger age group, the case is being reported.

Myopia and plasma cortisol.

Estimation of plasma cortisol by fluorometric technique desorbed by Mallingly's was carried out in 56 cases, including 38 cases of myopia (19 cases of simple myopia and 19 cases of degenerative myopia) and 18 normal individuals. Urinary 17-keto steroids/24 hours was also estimated by Zimmermann technique in 12 out of the 56 cases, which include 8 cases of myopia (4 cases of simple myopia and 4 cases of degenerative myopia) and 4 normal individuals as control. Plasma cortisol level is lower in simple and degenerative myopia than in normal subjects, but on statistical analysis the difference was not of much significance. Patients with simple myopia with positive family history showed lower value of plasma cortisol than patients with simple myopia with negative family history, the difference was also statistically insignificant (P-0.1). In degenerative myopia patients, with and without family history, there was very little difference in plasma cortisol level and statistically highly insignificant (P-0.8). Urinary 17 keto steroid/24 hour values are lower in simple and degenerative myopia than in normal subjects.

Growth hormone and diabetic retinopathy.

Growth hormone has been considered to be the cause of diabetic retinopathy. However the relationship between growth hormone responses and diabetic retinopathy has not been consistent. Moreover, the correlation (if any) between the severity of retinopathy and growth hormone changes are also not well defined. In the present study 23 diabetics (16 with retinopathy, 7 without retinopathy) and 8 non-diabetic healthy controls were studied. Serum growth hormone was measured in the fasting state and one hour after levodopa administration. The mean growth hormone levels were significantly higher in the diabetics as compared to controls, however there was no correlation between the mean growth hormone levels (either in the fasting state or after levodopa stimulation) and presence or absence of diabetic retinopathy although diabetics with retinopathy had significantly greater mean growth hormone response. The mean growth hormone was found to have no correlation with the fasting blood sugar levels. Diabetics with back ground retinopathy had significantly greater mean growth hormone levels than those with proliferative retinal changes.

ELISA (enzyme linked immuno sorbent assay) as a diagnostic tool in retinoblastoma.

Estimation of retinoblastoma antigen by double antibody sandwich ELISA technique was carried out in 20 histopathologically confirmed cases of retinoblastoma, 20 cases of pseudoglioma and 20 normal cases. The method of detection was done on the lines of Voller et al. (1976) with slight modification. The number of seropositive cases was more in cases with retinoblastoma.