Metabolic, pediatric, and systemic ophthalmology最新文献

In this review some of the so far identified mechanisms implicated in experimental and human cataractogenesis are reviewed. The oxidative insult, the osmotic insult (sugar cataracts and ionic imbalance cataracts), the role of tryptophan, of lysophosphatidylcholine and docohexanoic acid in primary and secondary cataracts are summarized. It is not always possible to identify the primary effect of cataractogenic mechanisms: the human "idiopathic" cataract is probably a multifactorial disease. In the aging lens and under stress conditions (osmotic and oxidative) the physiologic defense systems of the lens appear to be inadequate. Even if conditions of avitaminosis aren't the cause of deterioration of the adult human lens, it has been demonstrated that the supplementation or the deficiency of some nutritional factors may influence the course of cataract.

Serum free and total tryptophan levels have been measured in patients with cataracts and compared with the same levels in controls with clear lenses. No statistically significant differences have been demonstrated between the two groups of examined fasting subjects. Preliminary results seem to indicate that differences could be evident after L-tryptophan oral load.

This paper presents the results of the application of sodium hydroxybutyrate as 5% sugar syrup for the treatment of glaucoma patients. Common ophthalmological investigation methods and the oxyhemography were used. Fifty-two primary glaucoma patients (99 eyes) in various stages of disease and with different intraocular pressure levels were investigated. It was found that due to sodium hydroxybutyrate in 36 patients (69%) with statistical significance the visual field limits enlarged; in 15 patients visual acuity improved. The drug was efficient in the initial and developed glaucoma with normalized ophthalmotonus level. Significant improvement of the oxygen metabolism--oxygen saturation level of arterial blood and compensatory mechanisms functions of oxygenation-reduction processes in the majority of the patients was found. On the ground of the obtained findings the authors make a conclusion about the expediency of including 5% sodium hydroxybutyrate syrup in the complex treatment of primary glaucoma patients.

Physiopathologic or metabolic alterations in retinal blood vessels resulting in an ischemic state may be a prime trigger mechanism in neovasculogenesis and scar tissue formation. Rate of oxygen delivery may be the primary factor so the end-state disease may be rapid as in retrolental fibroplasia (marked reduction in vascular flow due to acute vasoconstriction) or delayed as in diabetes mellitus (chronic metabolism-induced low oxygen release rates parallel with chronic vasodilation).

The local anesthetic drug benoxinate (oxybuprocaine, Novesine) is hydrolyzed to 3-butoxy-4-aminobenzoic acid. A rapid and simple spectrophotometric method for benoxinate hydrolysis by human plasma was developed. Benoxinate is hydrolyzed enzymatically by an esterase present in the serum. Heat stability characteristics and apparent affinity values of the benoxinate metabolizing enzyme were in the same range compared to benzoylcholine chloride hydrolysis. Apparent Vmax-values differ by a mean factor of about 18 between the hydrolysis of both substrates. Considerable interindividual variability of benoxinate hydrolysis and inhibition of the enzymatic reaction by dibucaine and sodium fluoride has been observed. Furthermore, enzyme activity with benoxinate as substrate is positively correlated (P less than 0.001) with benzoylcholine chloride hydrolysis. Therefore, we assume that benoxinate is metabolized by human pseudocholinesterase (PCHE, E.C. 3.1.1.8) and that ocular side effects after benoxinate application may be caused by altered metabolism of this drug, depending on genetically determined variants of pseudocholinesterase.

The contrast sensitivity of patients undergoing hemodialysis therapy for chronic renal failure was measured and compared to that of a control group. Both contrast sensitivity and visual acuity of the patients were reduced. Ocular and fundoscopic exams revealed differences between the patients and controls, but these differences could not fully account for the visual deficits. The visual deficits could be expected to cause reduced visibility under everyday conditions for the patients.

This paper discusses a special group of diabetics (maturity onset) who present with a particular form of retinopathy. The pathology is restricted to the macular zone with minimal other retinopathic complications such as detachment, proliferans, or neovascularization. One hundred of these patients with circinate rings of perimacular exudate with edema have characterized and compared to a similar number of patients with diabetic retinopathy without circinate exudates. The statistically significant differences in age of onset, duration of the disease, and associated ocular findings are defined. Photocoagulation therapy has resulted in a satisfying response in a large number of patients, as well as in the control series where the contralateral eye with the same pattern of disease is untreated. It is concluded that this study group represents an identifiable segment of our diabetic retinopathy population which is highly amenable to successful photocoagulation therapy.

Twenty insulin-dependent diabetic teenagers from the Oxford pediatric diabetic clinic were recruited to study the relationship between diabetic control and retinal microvascular disease. Two patients (10%) had evidence of minimal background diabetic retinopathy on careful ophthalmoscopy. Retinal color photography and fluorescein angiography each revealed retinopathy in 5 patients (25%) and together revealed retinopathy in 7 patients (35%). Color photography demonstrated retinopathy which had not been discovered on ophthalmoscopy. The presence of retinopathy was related to the duration of diabetes (p less than 0.02) and the glycosylated hemoglobin level (p less than 0.01). It is concluded that multiple field color photography is a useful method of assessing patients with minimal or no ophthalmoscopic retinopathy.

Abnormal copper metabolism has been described in some pigmentary retinopathies. Albinism is a manifestation of a metabolic disorder in which lack of pigmentation is a prominent feature and changes in the retinal pigment epithelium are found as well. We examined the blood and urine of two groups of patients, albino and control groups, for copper, zinc and ceruloplasmin in serum and copper excretion in urine. We found in the albino group, elevated values of ceruloplasmin which was highly significant when compared to the control group. The mean copper concentration in serum was found to be high as well. The urinary copper was distinctly elevated in four patients of the albino group. Therefore, our results suggest that there might be a primary abnormality of copper metabolism in these patients.

A rare case of severe HSV necrotizing chorioretinitis of the neonate is reported. Massive, exudative chorioretinitis appeared in the equator bilaterally during HSV infection of the central nervous system. After subsidence of exudation, discrete chorioretinal scars appeared. Prominent calcification of the cerebral cortex progressed in parallel with scarring of the chorioretinal lesions.