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Biomedical subjects

R R Ober

Publications and source records attributed to R R Ober.

At least 19 recordsLinked to original sources
PubMed1999

Human diabetic neovascular membranes contain high levels of urokinase and metalloproteinase enzymes.

PURPOSE: Retinal neovascularization is one of the leading causes of blindness. A crucial event in this process is the remodeling and penetration of the capillary basement membrane by migrating endothelial cells. This process requires proteolysis of basement membrane components by a variety of proteinases. The objective of the present study was to determine the expression of proteinases in human retinal tissues showing active neovascularization. METHODS: Epiretinal neovascular membranes surgically removed from patients with proliferative diabetic retinopathy were analyzed by zymography, and the types and amounts of proteinases present in the tissues were determined. Retinas from nondiabetic donor eyes served as control specimens. RESULTS: Both the high- (54 kDa) and low- (33 kDa) molecular-weight forms of urokinase were present at significantly higher levels in neovascular membranes than in normal retinas. The pro forms of the matrix metalloproteinases (MMP) MMP-2 and MMP-9 were significantly elevated in the neovascular membranes in comparison with levels in normal retinas. In addition, the active forms of these enzymes were present in the membranes, whereas there was no detectable level of the active forms in normal retinas. CONCLUSIONS: Human diabetic neovascular membranes contain high levels of urokinase and MMP. The increased activity of proteinases in the final common pathway of retinal neovascularization indicates that inhibition of these enzymes may be a useful therapeutic target as an alternative approach in the management of proliferative retinopathies.

Aged↗
PubMed1994

Echographic findings in infectious endophthalmitis.

OBJECTIVE: To correlate the initial echographic findings in eyes with infectious endophthalmitis with the visual prognosis and causative microorganism. DESIGN: A retrospective review of the clinical and standardized ocular echographic findings in eyes with infectious endophthalmitis was performed. SETTING: University-based ophthalmology department. STUDY PARTICIPANTS: One hundred thirty-seven eyes (136 patients) with infectious endophthalmitis that were evaluated by the ocular echography service of the Doheny Eye Institute, Los Angeles, Calif, between January 1, 1981, and December 31, 1992. RESULTS: Four findings on initial echography were associated with poor initial vision: dense vitreous opacities, retinal detachment, macular detachment, and choroidal detachment. Five findings on initial echography correlated with poor final vision: dense vitreous opacities, vitreous membranes, the presence of retinal detachment, the extent of retinal detachment, and the presence of choroidal detachment. Change (decrease) in vision during the follow-up period was associated with the presence of combined vitreous and subhyaloid opacities, retinal detachment, and choroidal detachment. All eyes with initially clear vitreous on ocular echography had either early streptococcal or culture-negative endophthalmitis. Advanced streptococcal endophthalmitis correlated with the most severe vitreous inflammation, vitreous membranes, and the most extensive posterior vitreous detachment, whereas gram-negative endophthalmitis correlated with choroidal detachment on initial echography. Stepwise logistic regression analysis revealed that the presence of choroidal detachment, not gram-negative microorganisms, was the principal predictor of poor visual outcome in these eyes. CONCLUSION: Ocular echography is a useful method in the clinical evaluation and treatment of infectious endophthalmitis, especially in eyes with opaque media.

Adolescent↗
PubMed1994

The efficacy of a multimedia educational campaign to increase the use of eye care services.

PURPOSE: Effective eye care, both preventive and problem-directed, requires that patients actually see trained eye care providers. The authors examined the impact of a multimedia campaign on patient behavior in using eye care. METHODS: The authors surveyed 2000 individuals 1 year after they mailed in a contrast sensitivity screening card during a focused multimedia educational campaign. The response rate was 39%, allowing precision of estimates to +/- 4%. FINDINGS: Those who failed the screening test were much more likely to have had an eye examination in the year after the campaign and were much more likely to have seen an ophthalmologist for their care. Other important factors significantly related to using eye care services were: having had prior examinations, having a non-ophthalmologist physician, and having a history of cancer or macular degeneration. Importantly, 22% of those who failed the screening test thought they had had normal results when asked 1 year later. CONCLUSIONS: A focused multimedia campaign combined with interactive patient involvement can directly increase the use of eye care services. In addition, such care is much more likely to be delivered by ophthalmologist as opposed to other providers.

Contrast Sensitivity↗
PubMed1994

Immediate pars plana vitrectomy in the management of inadvertent intracameral injection of gentamicin. A rabbit experimental model.

PURPOSE: Acute retinal toxicity secondary to inadvertent intracameral injection of massive doses of gentamicin is a devastating complication of cataract surgery, for which no treatment, to date, either surgical or medical, has been shown to be effective. A rabbit experimental model was used to examine the effect of immediate pars plana vitrectomy in the management of inadvertent intracameral injection of gentamicin. METHODS: Twenty-seven rabbit eyes were subjected to lensectomy with or without preservation of the lens capsule. Aphakic rabbit eyes and rabbit eyes with an intact lens capsule were then subjected to injections of massive doses (4 mg and 20 mg) of gentamicin into the anterior chamber. Experimental eyes underwent an immediate pars plana vitrectomy and posterior segment lavage. The rabbits were killed after 7 days. Light microscopic examination was then performed to ascertain the degree of retinal damage caused by the injection. RESULTS: Rabbit eyes receiving immediate pars plana vitrectomy exhibited far less structural damage to the retina, as seen by light microscopy, than did corresponding control eyes. Furthermore, there appeared to be a protective effect of an intact lens capsule with regard to retinal damage. CONCLUSIONS: Immediate pars plana vitrectomy and posterior segment lavage may alleviate the effects of intracameral injection of gentamicin. This preliminary study demonstrates the need to perform further studies with a vascularized primate retina to evaluate immediate pars plana vitrectomy in the management of inadvertent intracameral injection of gentamicin.

Animals↗
PubMed1993

A combined anterior and posterior approach to cataract surgery in patients with chronic uveitis.

Although several recent papers have focused on the results of cataract surgery in patients with uveitis, little has been published on specific surgical techniques that are most appropriate to such cases. We have found that a combined anterior and posterior approach using extracapsular techniques (usually phacoemulsification) and pars plana vitrectomy, with or without intraocular lens placement, is best suited for selected uveitis patients who have cataract, vitreous opacities, and cystoid macula edema. This paper discusses the surgical techniques that we have found to be best for the management of these cases.

Adult↗
PubMed1993

Central retinal vein occlusion associated with retinal arteriovenous malformation.

PURPOSE/BACKGROUND: Retinal arteriovenous malformations can be seen in a variety of ways and have multiple, associated, ocular changes that can affect vision. The authors report two cases of retinal arteriovenous malformation. In each case, a central retinal vein occlusion developed. METHODS: Each patient underwent clinical examination and fluorescein angiography. One patient was followed over a long period of time. CONCLUSION: The authors propose that a turbulent flow, high intravascular volume, and arteriolar pressure in the venous side of the retinal arteriovenous malformation may lead to vessel wall damage, thrombosis, and occlusion. They also suggest that compression of the central retinal vein by the mass effect of the arteriovenous malformation on the optic nerve further leads to turbulence and thrombosis.

Arteriovenous Malformations↗
PubMed1993

Ocular findings in neonates after extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a modified, prolonged cardiopulmonary bypass procedure used to treat newborns who have reversible cardiac or respiratory failure. The venoarterial bypass technique requires cannulation of both the right carotid artery and the internal jugular vein, and after decannulation these vessels are permanently ligated. Left-sided retinal vascular changes after ECMO have been reported, and were attributed to ligation of these vessels. A retrospective review of the results of ocular examinations of 86 infants who had undergone ECMO therapy at Childrens Hospital in Los Angeles between March, 1987 and May, 1991 was conducted. Normal findings were noted in 73 infants. One infant had bilateral retinal vascular tortuosity, and 12 infants had incidental ocular findings, but there was no evidence of left-sided retinal hemorrhage, venous congestion, or tortuosity. Our results suggest that left-sided retinal vascular changes after ECMO do not occur, occur only rarely, or clear rapidly and result in no permanent retinal damage. To unequivocally rule out the possibility that ECMO can cause transitory retinal vascular changes, we recommend further prospective studies, with ocular examinations performed before, during, and after ECMO.

Extracorporeal Membrane Oxygenation↗
PubMed1988

Ocular perforation from a retrobulbar injection.

Proliferative vitreoretinopathy occurred in three of seven cases of ocular perforation from retrobulbar injection, resulting in a visual acuity of 20/200 or worse. Direct macular injury and macular pucker occurred in two cases each. Needle injury exit sites were in the posterior pole in all cases. Predisposing factors were not experimentally verified, but associated conditions included axial myopia, multiple injections, traditional superonasal gaze position, previous retinal buckling procedure, and enophthalmos.

Adrenal Cortex Hormones↗
PubMed1986

Rhegmatogenous retinal detachment after neodymium-YAG laser capsulotomy in phakic and pseudophakic eyes.

A retrospective study of 18 eyes in 17 patients with rhegmatogenous retinal detachments after neodymium-YAG laser posterior capsulotomy was performed to determine operative settings and to describe anatomic changes after the procedure in an effort to assess their relationship to subsequent retinal detachment. The laser energy required to create a capsulotomy did not appear to be excessive and the capsulotomy openings were not unusually large. The time between YAG capsulotomy and diagnosis of retinal detachment ranged from four to 82 weeks (mean, 28 weeks). The characteristics of the retinal detachments were similar to those after routine cataract extraction. Retinal reattachment surgery was ultimately successful in all 18 eyes. Both YAG laser and knife-needle posterior capsulotomies may increase the risk of subsequent rhegmatogenous retinal detachment as a result of opening the capsule.

Adult↗
PubMed1984

Punctate inner choroidopathy.

Ten moderately myopic women had blurred vision, light flashes, or paracentral scotomas associated with small yellow-white lesions of the inner choroid and pigment epithelium. Most lesions had an overlying serous detachment, were hyperfluorescent, and leaked fluorescein during the acute phase. The lesions healed into atrophic scars and became progressively more pigmented with time. Subretinal neovascular membranes later developed from scars in six patients. Vision was usually only minimally affected unless the lesions were subfoveal or unless choroidal neovascular membranes subsequently occurred. Extensive laboratory studies were noncontributory.

Adult↗
PubMed1983

Central serous choroidopathy in pregnancy.

Central serous choroidopathy is an infrequent complication of pregnancy. A serous detachment of the macula was seen in three women during the course of their normal pregnancy. All patients showed resolution of the macular serous detachment in the third trimester, with resultant retinal pigment epithelial mottling; symptoms resolved in all patients post partum. Laboratory testing was not beneficial in establishing the cause of this disorder.

Adult↗
PubMed1983

Subretinal neovascularization in the Vogt-Koyanagi-Harada syndrome.

Two Hispanic patients with Vogt-Koyanagi-Harada (VKH) syndrome each developed a disciform lesion involving the macula of one eye several months after the onset of symptoms. Each had extraocular manifestations which included pleocytosis of the cerebrospinal fluid. The disciform lesions were associated with retinochoroidal anastomoses, a finding not previously reported in VKH syndrome. Each patient had a separate extramacular disciform lesion in the same eye. Two other Hispanic patients with diffuse bilateral intraocular inflammation had ocular findings consistent with VKH syndrome. One of these patients developed bilateral peripapillary disciform lesions and the other developed a disciform macular scar in one eye. Fluorescein angiography in each patient showed early irregular hyperfluorescence with late intense staining. The disciform detachments occurred in areas of reactive proliferation of the retinal pigment epithelium, and we postulate that growth of subretinal new vessels occurred through areas of Bruch's membrane that were damaged by the inflammation.

Adolescent↗
PubMed1983

Experimental retinal tolerance to liquid silicone.

The effect of intraocular liquid silicone on the electroretinogram (ERG) and on retinal morphology was studied in rabbits. After vitrectomy, liquid silicone (1000 centistokes) or balanced salt solution (BSS) was injected into the eyes. The intraocular silicone was well tolerated clinically in all eyes that were followed over a period of 3 days to 6 months. ERG responses were equivalent in operated control and silicone-injected eyes. Light and electron microscopy showed slight but comparable changes in both operated control and silicone-injected eyes that were consistent with either fixation artifact and/or surgical trauma. The results suggest that exposure to silicone for up to 6 months does not have a toxic effect on the rabbit retina.

Animals↗
PubMed1982

Results of anterior segment surgery with vitrectomy instruments.

We used closed-eye endosurgery to treat 58 patients with anterior segment problems. These included nonsenile cataract, residual lens material, pupillary membranes, vitreocorneal touch, aphakic pupillary block glaucoma, intraocular lens complications, epithelial ingrowth, and total hyphema. Thirty-five eyes showed an increase in visual acuity of more than two Snellen lines, 13 eyes demonstrated no change, and ten eyes lost more than two lines. Complications included endophthalmitis, retinal detachment, retinal tears, increased intraocular pressure, postoperative hemorrhage, and bullous keratopathy.

Adolescent↗
PubMed1980

Retinal arteriovenous anastomoses in the Vogt-Koyanagi-Harada syndrome.

A 15-year-old black girl had acute bilateral uveitis and other features of the Vogt-Koyanagi-Harada syndrome. Several months after the onset of her illness, she developed acquired retinal arteriovenous anastomoses in both eyes. By using fluorescein angiography, we documented that the anastomoses were collateral vessels developing in areas of damaged retinal pigment epithelium and retinal capillaries.

Adolescent↗