Metabolic, pediatric, and systemic ophthalmology最新文献

The specific activities of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase, EC3.1.4.37) in erythrocyte membranes from five patients with active multiple sclerosis (MS) and five normals were compared. The CNPase assay used 2',3'-cyclic NADP as the substrate in an enzyme coupled reaction to produce fluorometrically detectable NADPH. The specific activity of CNPase in the MS and normal groups were 19.2 +/- 2.3 and 28.7 +/- 1.8 mumol/h/mg protein, respectively. The difference was significant with p less than 0.006, based on a one-tailed t-test.

Spontaneously diabetic dogs were treated initially (the first 1/2 yr) with i.v. prostacyclin and oral aspirin and then for 1 yr with varying doses of aspirin alone. At this time cataracts prevented visualization of retinae, and one eye of each animal was removed for examination of the vasculature of the trypsin digested retinae. Studies of the blood during the course of treatment showed an elevation of plasma cyclic adenylic acid and marked lowering of inordinately high platelet count and platelet aggregation. Treatment was stopped and after an additional 1/2 year the animals were euthanized and the fellow eye removed for retinal study. Although just three diabetic animals survived for binocular retinal histology, there were no discernible differences in the retinal vasculature in the fellow eyes of a given animal, and in only one of these three animals were there clear signs of diabetic retinopathy. We must conclude, therefore, that in spite of relative normalization of platelet function in the parameters measured during the course of treatment, we cannot yet claim a salutary effect of treatment on the diabetic retina. Cataracts prevented us from having better information on diabetic retinae prior to treatment and a redesigned study would have to include unilateral histological retinal examination before any treatment is started to determine if, indeed, improved platelet physiology slows or reverses changes in the diabetic retina.

The compounds benzyloxycarbonyl-L-leucyl-hydroxamate (Z-Leu-NHOH), benzyloxycarbonyl-glycyl-hydroxamate (Z-Gly-NHOH) and 2-mercaptoacetyl-L-phenylalanyl-L-leucine (HSAc-Phe-Leu) are potent inhibitors of Pseudomonas aeruginosa elastase. The effect of these inhibitors on growth and protease secretion by the bacteria was studied under conditions where the organisms secrete elastase as the major proteolytic constituent. Z-Gly-NHOH and Z-Leu-NHOH inhibited bacterial growth and enzyme secretion by 40 and 30%, respectively, although the inhibition by Z-Leu-NHOH was expressed only when growth was in dialysed medium. Inhibition of growth by both compounds was first observed at the end of the logarithmic phase of growth, suggesting that these compounds are not toxic to the bacteria. HSAc-Phe-Leu did not inhibit growth or enzyme secretion. The level of HSAc-Phe-Leu in the medium decreased constantly during incubation, probably because of gradual oxidation of the -SH group. The rate of this decrease was markedly enhanced in presence of the bacteria, suggesting that HSAc-Phe-Leu is either consumed or destroyed by the organisms. We propose that the partial reduction of growth exerted by the hydroxamate derivatives is the result of inhibition of the extracellular proteases by these compounds. HSAc-Phe-Leu failed to inhibit growth because of its rapid loss during incubation with the bacteria. Since the three inhibitors have no antibacterial effects, their therapeutic potential should be examined in combination with antibiotics. Experimental treatment with HSAc-Phe-Leu should be frequent in order to overcome its loss in presence of the organisms.

Tear secretion was examined in 194 patients treated with oral beta blockers, mainly with propranolol, oxprenolol, pindolol, and atenolol, and metaprolol and in 185 healthy control subjects. Statistical analysis included the Student's t test used to compare the mean values of tear secretion and the chi square test used to compare the percentage of eyes with tear hyposecretion between treated and control groups. This statistical study showed clearly that oral beta blockers significantly reduce the tear secretion.

A simple method of aphakic refraction using ultrasonographic axial length measurement and keratometry was tried on 97 eyes of adult aphakic patients. The refractive errors determined by this method and by retinoscopy were compared to the subjective refraction of the same eyes. The ultrasonographically determined refractive errors were significantly nearer the subjective refraction than were the retinoscopically determined refractive errors.

A case of an accidental exposure to a high intensity Q-switched infrared laser beam is described. A paramacular burn, splinter hemorrhages on the disc margin, and vitreous hemorrhage were the initial findings. Later, a paramacular pucker developed, causing reduction in visual acuity to 6/12. Microvascular accident on the disc margin is assumed to be the cause of a paracentral scotoma located fairly far from the image area.

The necessity for special operating rooms used exclusively for intraocular surgery, careful preparation of the patient and prevention of infection with preoperative antibiotics is emphasized. Also, the graft must be obtained and stored in aseptic and atraumatic conditions. If, in spite of these precautions postoperative endophthalmitis does occur, the graft must be replaced by a fresh donor cornea and the purulent material eliminated by irrigation, as long as the infection is still limited to the anterior segment of the eye.

Bovine corneal endothelial cells can be grown successfully in culture. Growth factors such as FGF and EGF are shown to have a significant role in supporting an active proliferation of bovine corneal endothelial cells in culture as well as an effect on the ability of these cultures, to adopt a morphological configuration and phenotypic expression upon reaching confluence similar to their in vivo counterparts. Cultured bovine corneal endothelial cells provide us with an excellent in vitro model to study differentiated functions of the corneal endothelium. Using these cultures, we describe in the present review the exploration of a new differentiation property of the corneal endothelium such as the role of corneal endothelial cells in the inhibition and removal of active thrombin, as well as the study of a basic problem in cell biology such as the mechanism of action of growth factors.