Aqueous humour lactic acid and proteins in eyes with iris neovascularization.

The content of lactic acid and proteins in the aqueous humour of eyes with neovascularization of the iris (NVI) of various etiology was determined. The results were analysed for any possible correlation with the angiogenesis observed in such eyes. Aqueous humour from patients with immature senile cataracts served as the control. The total protein concentration in cases of NVI (mean +/- SD, 345.7 +/- 161.0 mg/dl; n = 15) was significantly raised (P < 0.001) as compared with the control values (mean +/- SD, 30.91 +/- 14.95 mg/dl; n = 12). On the other hand, the concentration of lactic acid in cases of NVI (mean +/- SD, 45.97 +/- 15.5 mg/dl; n = 13) was significantly lower (P < 0.01) as compared with the controls (mean +/- SD, 65.86 +/- 10.9 mg/dl; n = 8). These findings show that angiogenesis is not associated with a raised level of lactic acid in the aqueous humour, whereas the elevated protein values are suggestive of a breakdown of the blood-aqueous barrier.

India-US case-control study of age-related cataracts. India-US Case-Control Study Group.

In a hospital-based case-control study of 1441 patients with age-related cataracts and 549 controls, we studied associations between types of cataract--nuclear, cortical, posterior subcapsular, and mixed--and a number of physiologic, behavioral, environmental, and biochemical variables. Using polychotomous logistic regression analysis, we found an increased risk of cataract with lower educational achievement (all types of cataract), decreased cloud cover at place of residence (all types), use of aspirin less than once a month (posterior subcapsular and mixed), diets low in selected nutrients (posterior subcapsular, nuclear, and mixed), higher blood pressure (nuclear and mixed), lower body mass index (nuclear and mixed), use of cheaper cooking fuels (cortical, nuclear, and mixed), and lower levels of an antioxidant index based on red blood cell levels of glutathione peroxidase and glucose-6-phosphate dehydrogenase and plasma levels of ascorbic acid and vitamin E (posterior subcapsular and mixed). All risks cited were significantly different from those for the other cataract types, a finding that emphasizes the need to investigate the epidemiology of specific types of cataract.

Chlamydial serology in uveitis.

Ninety seven sera, 53 from patients with Acute Anterior Uveitis and 44 from age and sex matched controls were tested for antichlamydial antibodies employing a recently developed technique of ELISA. Higher positivity of 27.0% was recorded in controls as against 17.0% in patients. The difference was statistically insignificant. All the subjects had trachoma at stage II-IV. Age and sex did not seem to influence the findings in both, the cases and controls. Through this study, the role of Chlamydia in the etiology of A. A. U. is not ascertained. Further studies are recommended.

Pathogenesis of epidemic dropsy glaucoma.

Thirty-one cases of epidemic dropsy with raised intraocular pressure were studied. Glaucoma was bilateral in all, with open angles and no signs of anterior segment inflammation. The outflow facility was unimpaired (C value, 0.24 +/- 0.09 microL/min/mm Hg). Aqueous bioassays revealed significantly elevated prostaglandin E2 level (23.33 +/- 4.32 ng/mL) and histamine activity (13.0 +/- 2.76 ng/mL) in all samples from patients with epidemic dropsy glaucoma as compared with negligible levels in control samples from patients with open angle glaucoma. Aqueous biochemical analysis revealed increased total protein level (1.03 +/- 0.10 g/L) with a normal globulin pattern as compared with controls (0.26 +/- 0.08 g/L). On histopathologic and histochemical testing, a normal trabecular meshwork was found in 11 of the 12 trabeculectomy specimens. It is concluded that dropsy glaucoma is hypersecretory in nature; prostaglandin and histamine release may have significant roles in its pathogenesis.

Tear and serum immunoglobulins during corneal graft rejection.

Tear and serum concentrations of IgG, IgA, and IgM were estimated in serially drawn samples of 50 patients undergoing optical keratoplasty. Fifteen healthy individuals served as controls. Samples were collected at different postoperative intervals. An immunological rejection phenomenon was observed in nine patients. The rejection could be reversed in five of these nine cases. A decline in serum immunoglobulins was observed during the postoperative follow-up of these cases. This was unrelated to rejection phenomenon and was attributed to systemic steroid therapy. In tears, IgM was not detectable in majority of samples. No significant variation in tear IgA levels was observed between the cases where rejection was reversed and the ones in which it resulted in an opaque graft. In contrast, significant tear IgG increase was observed during the rejection phenomenon. The increased IgG levels returned to the basal value in each case in which rejection was reversed, but remained elevated much above basal and maximum control values in cases in which rejection could not be reversed. This differential response of tear IgG was highly significant. Our results suggest that raised tear IgG levels and its persistence despite therapy may be an indicator of corneal transplant rejection.

Bilateral simultaneous corneal graft rejection--role of tear immunoglobulins.

A report is made on an unusual case of corneal graft which was clear for well over a decade, and then manifested allograft rejection phenomenon concurrently in both eyes initiated by keratoplasty in the second eye. A bilateral and simultaneous corneal graft rejection in an individual does not seem to have been reported previously. Serial tear immunoglobulin (IgG) levels, which were normal in the initial postoperative period, demonstrated an elevation throughout the rejection phenomenon. The possible significance of this rise in the tear IgG levels is discussed.

A simplified ELISA for anti-receptor antibodies in myasthenia gravis.

Nicotinic acetylcholine receptor (nAchR) from triton extracts of muscle adsorbed specifically and optimally to microtitration plates at pH 7.4 rather than at pH 9.6. An ELISA for anti-receptor antibodies in myasthenia gravis based on direct adsorption of the receptor at pH 7.4 is described (direct assay). The direct assay compares very well in sensitivity and specificity with an indirect assay, in which the receptor was attached through alpha-bungarotoxin adsorbed on the solid phase (correlation coefficient 0.94).

Lactate dehydrogenase levels in aqueous humor and serum in retinoblastoma.

The lactate dehydrogenase (LDH) levels were measured in the aqueous humor and serum of 16 patients (20 eyes) with retinoblastoma. The enzyme activity in the aqueous humor and serum did not show any correlation with each other. Age of presentation, age of enucleation, sex and disease duration had no correlation with the enzyme level either in the serum or aqueous humor. The stages of retinoblastoma were classified in Stages I to V: eyes with Stages I to III were included in Group 1, and those with Stages IV and V were in Group 2. The differences in LDH levels in the aqueous humor and in the aqueous to serum LDH ratio were highly significant (P less than 0.001) by Wilcoxon's nonparametric test between Groups 1 and 2. A considerable rise in the aqueous humor LDH level was observed without any alterations in the serum levels in Group 2 as compared to Group 1; hence the aqueous/serum ratio was increased in the former group. The LDH level in the aqueous humor and the aqueous/serum ratio can be a diagnostic tool in retinoblastoma of Stages IV and V. Though the lower aqueous levels of LDH do not rule out the presence of the disease, the higher levels are definitely helpful for diagnosis of retinoblastoma.

alpha-Bungarotoxin aggregates on radioiodination with chloramine-T but not with iodogen.

The presence of polymer(s) of radioiodinated bungarotoxin (Bgt) in preparations iodinated with chloramine-T or with iodogen, was investigated by chromatography on Sephadex-G50. In addition to a monomeric peak (P2), chloramine-T preparations showed a high content of polymeric forms (16-43%) eluting in the void volume (P1), present only to the extent of 1-3% in iodogen preparations. In purified [125I]Bgt prepared by the iodogen method, the content of P1 increased on treatment with chloramine-T, in the absence of radioiodine. The nonspecific binding of [125I]Bgt to DE-81 filter discs was high in the case of chloramine-T preparations and proportional to the content of P1 in each batch. Purified P1 (polymer) but not P2 (monomer) showed a concentration-dependent high degree of binding to DE-81 discs.

A spectrophotometric method for simultaneous estimation of phenytoin and carbamazepine.

A 0.5 ml sample of serum, containing different antiepileptic drugs, singly or in combination, was made alkaline, overlayered with isooctane, and steamed in the presence of KMnO4. The spectra of oxidized products in the organic layer were recorded in the UV range. Oxidized phenobarbitone and primidone show no absorption peak; diazepam a delta-max at 228 nm; phenytoin at 247 nm; and carbamazepine at 247 nm and 372 nm. Consequently, phenobarbitone and diazepam do not interfere in phenytoin quantitation, but carbamazepine does. The contribution of carbamazepine at 247 nm was calculated from the absorption at 372 nm and the ratio of its molar extinction coefficients at the two wave lengths. This was subtracted from the total A247 values to get the actual values due to phenytoin. Thus, a method for simultaneous analysis of carbamazepine and phenytoin in a single sample has been developed.