Potentiometric titration of carboxyalkylated poly vinyl alcohol with mono-, di-, and trichloroacetic acids with alkali metal hydroxides and quaternary ammonium bases

Potentiometric titrations of the products obtained by polyvinyl alcohol first carboxyalkylated with chloroacetic acids were conducted with LiOH, NaOH, KOH, NH4OH, N[CH3]4OH and N[C2H5]4OH in deionized water, and with mixtures of LiOH and tetraethylammonium hydroxide of varying proportions. The results were expressed in terms of the modified Henderson-Hasselbach equation pH = pKa-n log [[1-alpha]/alpha]. Appreciable shifts in the titration curves to lower pH values were observed, accompanied by increase of the calculated capacity of the polyelectrolyte, in the sequence N[C2H5]4OH < N[CH3]4OH < NH4OH < KOH < LiOH. The values of pKa [at alpha = 0.5] where alpha is the degree of neutralization and is found to increase with the size of counterion. The titration curves obtained with mixture of LiOH and N[C2H5]4OH showed that the calculated values of capacity and the position of the curves were intermediate between those obtained with solutions of the single cations

Role of visual evoked potential in management of rhegmatogenous retinal detachment

Fifteen cases with rhegmatogenous retinal detachment have been studied pre-and postoperatively by the visual evoked potential [EVP]. The EVP technique involves the whole field and left-right; upper-lower hemifield. The patients are divided into four groups according to the extent of detachment. There are improvement in the mean latencies and amplitudes after the operation for each group. The first group shows 5.8% of improvement of the mean latency, 101.2% for the mean amplitude; the second group 21.85% and 72.39%; the third group 27.32% and 145.31%, and the fourth group 28% and 202.02%. When the macula was not detached before the operation, the mean latency stows 12.95% improvement compared to 32.90% when the macula was detached. The recent retinal detachment shows 19.9% improvement of the mean latency compared of the mean latency pared to 27.64% for the old detachment. This early study shows the value of EVP in evaluating retinal detachment pre- and postoperatively

Ocular adnexae and ocular injuries - evaluation of intralesional corticosteroid injection for the treatment of chalazia

Thirty cases of chalazia were injected intralesionaly with corticosteroids. They were divided into three groups according to the size of chaiazion. 100% cure rate was achieved in small chalazia less than 3 mm in diameter. A moderate result [50% cure rate] was seen in medium sized chalazia. In large chalazia more than 6 mm in diameter the results are not encouraging. Histopathological changes after intralesional injection of corticosteroied was reported

Glaucoma and cataract timolol, betaxolol and befunolol therapy in chronic simple glaucoma, efficacy and side effects

The effect of timolol meleate 0.5% betaxolol hydrchioride 0.5% and befunolol hydrochioride 0.5% in 48 patients with chronice open angle glaucoma were compared. The overall mean decrease in the intraocular pressure was 6.3 mm Hg and 7.1 mmHg with timolol, betaxolol and befunolol therapy respectively. The Lop was successfully controlled during the study without adjunctive therapy in 62.1% 65.5% 66.7% with timolol, betaxolol and befunolol therapy respectively. No significant variation was observed in the pulse or blood pressure in the different groups

Study of histopathology of recurrent pterygium

The authors describe the histopathological picture of recurrent pterygium

Serum vitamin A and serum albumin in keratomalacia

The relative importance of vitamin A and protein deficiencies in the aetiology of keratomalacia remains less certain. Serum vitamin A, and serum albumin were estimated in 45 cases of malnutrition in infants the results suggested that the basic underlying aetiologic factors in malnutrition keratopathy was vitamin A deficiency

Trabeculectomy operation for aphakic glaucoma

Trabeculectomy operations have been done for 25 patient of aphakic glacuoma. Seventeen of them have intact anterior hyaloid membrane and the remaining 8 cases have vitreous filling the anterior chamber which needed in addition to perform anterior vitrectomy. The ersults especially when the anterior vitreous face is well formed are encouraging