Metabolic, pediatric, and systemic ophthalmology最新文献

The improved survival of very premature infants is probably responsible for the moderate increase in incidence of RLF in the past few years. Because of the new cases of RLF, ophthalmologists should continue to focus their attention on this retinopathy of the premature infant. The pathogenesis of RLF and the role of oxygen, along with a brief discussion of newer concepts, are discussed.

Ten insulin-dependent diabetic subjects under the age of 44 years with duration of diabetes from 10 to 30 years were studied. All demonstrated a pattern of rapid development of retinovascular proliferation with few or late symptoms. Retinal changes which threatened or ultimately destroyed vision developed while good visual acuity was maintained. Fifty percent of these had advanced beyond the stage at which treatment is most beneficial when first examined. The "silent" progression of this binding disorder permits it to escape detection and therapeutic intervention prior to a stage of advanced damage. Early and regular ophthalmic assessment of the young, insulin-dependent diabetic is essential for the prevention of blindness.

The present investigation analyzes the results of the ERG and VER studies after argon-laser photocoagulation of the papillomacular region and after panretinal argon-laser photocoagulation. The author stresses the possibility of photocoagulation of the papillomacular region without risk of damaging the papillomacular fibers as well as the observation that panretinal photocoagulation performed under identical parameters does not affect electric activity (and consequently the anatomical integrity of the retina) to the same extent in different eyes. The ERG could thus be used for an objective assessment of the degree of adequacy of panretinal photocoagulation.

Long-term unilateral blocking of the trabecular meshwork with Dextran blue 2000, in 10 rabbits, produced intraocular pressure rise and a significant gain in vitreous mass. These experimental findings were in variance with the previous clinical observation of definitely reduced vitreous volume in phacolytic glaucomatous patients. The reason for this discrepancy is discussed.

Data are presented to suggest that hyaluronidase can act as a virus spread factor in herpes simplex eye infection by both degrading tissue mucopolysaccharide and interfering with the antiviral effects of the interferon system. Most of herpes simplex eye infections are accompanied by contamination by various bacterial species capable of hyaluronidase production. Based on these data, a hypothetical model for the involvement of bacterial hyaluronidase in controlling the clinical course of ocular herpes simplex infection is suggested. The model can apply to other viral infections accompanied by bacterial contaminations, and provides a new therapeutic approach to such cases.

A set of dizygotic twins, both born prematurely, developed herpes simplex encephalitis shortly after birth. The second twin had unilateral keratoconjunctivitis and bilateral endophthalmitis and subsequently died from disseminated herpes infection. Herpes simplex, type 2, was isolated from conjunctiva of both eyes, cerebrospinal fluid, nasopharynx and trachea. Histologic examination of the eyes revealed bilateral endophthalmitis with a necrotizing retinitis. Intranuclear inclusion bodies were demonstrated by light microscopy in the retina, choroid and iris, and virus particles were demonstrated by electron microscopy in the retina. The other twin recovered from a much milder disseminated herpes simplex infection without apparent ocular involvement. During pregnancy, the mother had vaginitis which was suspected, but not documented, as being herpetic in origin. The father was diagnosed as having a penile infection caused by herpes simplex. Repeated attempts to locate the family of the surviving baby girl in order to obtain follow-up information have failed.

In intact cultured rabbit corneal epithelial cells we have identified [3H]dihydroalprenolol ( [3H]DHA) and [3H]quinuclidinyl benzilate ( [3H]QNB) binding activities which meet criteria for beta-adrenergic and muscarinic cholinergic receptors. For saturable, propranolol-sensitive [3H]DHA binding, Bmax = 0.374 +/- 0.063 fmol/microgram protein; KDHA = 12.5 +/- 2.4 nM from Scatchard analysis. For saturable, atropine-sensitive [3H]QNB binding, Bmax = 0.403 +/- 0.053 fmol/microgram protein; KQNB = 15.4 +/- 0.7 nM. The order of potency of unlabeled adrenergic agonists in competition for [3H]DHA sites was isoproterenol greater than epinephrine greater than norepinephrine. For unlabeled cholinergic agonists competing for [3H]QNB sites, the order was oxotremorine greater than acetylcholine greater than or equal to carbamylcholine. Acetylcholine did not inhibit [3H]DHA binding, nor did isoproterenol or choline inhibit [3H]QNB binding. Effectiveness of drugs in stimulating cAMP or cGMP accumulation closely paralleled efficacy in competition for [3H]DHA or [3H]QNB sites. Results confirm the presence in intact cultured corneal epithelial cells of beta-adrenergic receptors (demonstrated by others in corneal membrane suspensions), identify in intact cells muscarinic cholinergic receptors (not previously detected in broken cell preparations), and supply evidence for receptor-mediated regulation of cyclic nucleotide levels in these cells, further supporting our hypothesis of bidirectional influence by cAMP-mediated beta-adrenergic and cGMP-mediated cholinergic "first messengers" on proliferation during healing of corneal epithelial defects.

Early experience with the refractive keratoplasty techniques of José Barraquer--keratophakia and hypermetropic keratomileusis is presented. In contradistinction to the alloplastic lens substitutes currently being employed for the integral correction of aphakia, Barraquer's techniques would seem to offer a more permanent, more physiologic, full-time optical correction of the aphakic state. Their use is limited only by the condition of the patient's cornea and, in fact, may be applied not only in aphakia but also in phakic eyes with higher degrees of hyperopia or myopia. In the opinion of the authors, the refractive keratoplasty techniques of Barraquer can be performed by any well-instructed ophthalmic surgeon. These techniques offer to many patients a satisfactory, and potentially a physiologically superior alternative to alloplastic lens substitute for aphakic correction.

Alteration in prostanoid and TXA2 production are involved in the development of diabetic microangiopathy underlying DR. Diabetic microangiopathy is characterized by abnormalities in platelet function and increased susceptibility to thrombus formation. The synthesis of excessive amounts of PGs and TXA2 by platelets obtained from diabetic patients is underlying alteration in platelet responsiveness seen in diabetes mellitus. An associated reduction in PGI2 by endothelial blood vessels results in further disruption of the homeostatic mechanism regulating the aggregatory process. However, PGI2 behaviour in different tissues, and in blood vessels of varied calibre is yet unclear. PGI2 synthesis is restored to normal on reduction of blood glucose levels. Restoration of the synthesis of both prostanoids and PGI2 to normal, might be achieved by using drugs that inhibit prostanoid and TXA2 formation as well as by controlling glucose blood levels. Affecting the imbalance of prostanoid and TXA2 seen in diabetes might be of clinical implication in prevention and treatment of DR.