Biomedical subjects

K Chatzistefanou

Publications and source records attributed to K Chatzistefanou.

6 recordsLinked to original sources

PubMed1998

Characteristics of uveitis presenting for the first time in the elderly.

OBJECTIVE: This study aimed to describe the clinical characteristics of uveitis presenting de novo in the elderly. DESIGN: The study design was a description of a retrospectively identified case series. PARTICIPANTS: A population of 138 patients (209 eyes) with uveitis beginning after age 60 was analyzed. RESULTS: Uveitis in the elderly accounted for 10.4% of the authors' uveitis population. The localization of uveitis was anterior in 56.5% of patients, intermediate uveitis was diagnosed in two patients (1.4%), posterior uveitis was found in 25.4%, while 16.7% of patients presented with panuveitis. Idiopathic uveitis accounted for the majority of cases (31.2%), whereas herpes zoster ophthalmicus (11.6%), herpes simplex virus (6.5%), presumed sarcoidosis (5.8%), syphilis (4.3%) ankylosing spondylitis (4.3%), and birdshot chorioretinopathy (3.6%) were the most frequent specific diagnostic entities. Secondary elevation of intraocular pressure was common (67 eyes, or 32%). The development of macular edema complicated 28.7% of cases (60 eyes). Two cases of intraocular lymphoma were identified in 19 diagnostic vitreous biopsy specimens. Fifty-two percent of eyes retained visual acuity of 20/40 or more; 32.6% had final visual acuity worse than 20/100. CONCLUSIONS: Uveitis presenting for the first time in the elderly is not uncommon. Idiopathic uveitis accounts for the majority of cases, and herpes zoster ophthalmicus and herpes simplex virus are particularly prevalent. Intraocular lymphoma does not predominate in this age group. With adequate control of intraocular inflammation and its sequelae, the visual prognosis in patients in this age group with uveitis is relatively good.

Aged↗

PubMed1997

Posterior capsule opacification after cataract surgery in patients with uveitis.

PURPOSE: To compare the incidence rate of posterior capsule opacification (PCO) after phacoemulsification and standard extracapsular cataract extraction (P/ECCE) in eyes with antecedent uveitis with the incidence rate in eyes without any history of intraocular inflammation. DESIGN: Review of records of 108 eyes of 78 patients with uveitis and 122 eyes of 106 patients with no uveitis who underwent P/ECCE. Rates of PCO were compared by the log-rank test of differences in the Kaplan-Meier survival curves. Proportional hazards regression models provided estimates of the relative risks of PCO among uveitic compared to nonuveitic eyes. MAIN OUTCOME MEASURES: Performance of neodymium: YAG laser posterior capsulotomy was used as a proxy measure for the main outcome of visually significant PCO. RESULTS: Study patients ranged in age from 6 to 81 years (median, 44.5 years) among those with uveitis and 27 to 96 years (median, 68.5 years) among those without uveitis (P = 0.0001). Crude incidence rates for visually significant PCO were 54% over a mean follow-up of 4.3 years in uveitic cases and 40% over a mean follow-up of 3.9 years among nonuveitic cases (P = 0.02). Estimates of PCO incidence (95% confidence interval) in uveitic eyes derived from the Kaplan-Meier models were 38.5% (range, 28.9%-48.2%) at 1 year and 56% (range, 45.8%-66.3%) at 3 years, and estimates among nonuveitic eyes were 11.5% (range, 6.2%-16.8%) at 1 year and 38.4% (range, 29%-47.8%) at 3 years. These rates of PCO among patients with uveitis and those patients without uveitis differed significantly by the log-rank test (P = 0.004). However, after adjusting for the younger age of patients with uveitis, the rates of PCO were no longer statistically different. CONCLUSIONS: The apparent higher rate of PCO in patients with uveitis is primarily due to their younger age at the time of surgery. A moderately increased independent risk of PCO from uveitis cannot, however, be ruled out by this study.

Adolescent↗

PubMed1996

Vascular endothelial growth factor is sufficient to produce iris neovascularization and neovascular glaucoma in a nonhuman primate.

OBJECTIVE: To determine whether the angiogenic peptide vascular endothelial growth factor (VEGF) is sufficient to produce iris neovascularization in a nonhuman primate (Macaca fascicularis). METHODS: Eight eyes of 4 animals were studied. The 165-amino acid isoform of human recombinant VEGF (VEGF165) was injected into the vitreous of 5 cynomolgus monkey eyes (doses ranging from 0.25-2.5 micrograms per injection). Equal amounts of inactivated human recombinant VEGF (2 eyes) or vehicle (1 eye) were injected into contralateral control eyes. Eyes were assessed by slitlamp biomicroscopy, tonometry, iris color photography, fluorescein angiography, histopathologic examination, and immunostaining with antibodies against proliferating cell nuclear antigen. RESULTS: All 5 bioactive VEGF-injected eyes developed neovascularization with dilated and tortuous iris vessels that leaked fluorescein. None of the 3 control eyes exhibited any iris vascular changes. Inflammation was absent in both treatment groups. A dose response to VEGF was observed in the single animal that received 2.5 micrograms and 0.25 microgram in the right and left eyes, respectively. Iris vessel endothelial cells were positive for proliferating cell nuclear antigen in the bioactive VEGF-injected eyes only. Injections of 1.25 micrograms of VEGF every 3 days during a 30-day period produced advanced iris neovascularization, ectropion uvea, and neovascular glaucoma. CONCLUSIONS: Intravitreal injections of recombinant human VEGF165 in amounts comparable with those measured in eyes with active neovascularization are sufficient to produce noninflammatory iris neovascularization in a nonhuman primate. Prolonged exposure to VEGF165 can produce ectropion uveae and neovascular glaucoma.

Animals↗

PubMed1996

Intravitreous injections of vascular endothelial growth factor produce retinal ischemia and microangiopathy in an adult primate.

PURPOSE: The purpose of the study is to determine the effect of exogenous vascular endothelial growth factor (VEGF) on the primate retina and its vasculature. METHODS: Ten eyes of five animals were studied. Physiologically relevant amounts of the 165 amino acid isoform of human recombinant VEGF were injected into the vitreous of six healthy cynomolgus monkey eyes. Inactivated human recombinant VEGF or vehicle was injected into four contralateral control subject eyes. Eyes were assessed by slit-lamp biomicroscopy, tonometry, fundus color photography, fundus fluorescein angiography, light microscopy, and immunostaining with antibodies against proliferating cell nuclear antigen and factor VIII antigen. RESULTS: All six bioactive VEGF-injected eyes developed dilated, tortuous retinal vessels that leaked fluorescein. Eyes receiving multiple injections of VEGF developed progressively dilated and tortuous vessels, venous beading, edema, microaneurysms, intraretinal hemorrhages and capillary closure with ischemia. The severity of the retinopathy correlated with the number of VEGF injections. None of the four control eyes exhibited any abnormal retinal vascular changes. The endothelial cells of retinal blood vessels were proliferating cell nuclear antigen positive only in the bioactive VEGF-injected eyes. CONCLUSION: Vascular endothelial growth factor is sufficient to produce many of the vascular abnormalities common to diabetic retinopathy and other ischemic retinopathies, such as hemorrhage, edema, venous beading, capillary occlusion with ischemia, microaneurysm formation, and intraretinal vascular proliferation.

Animals↗

PubMed1996

Experimental corneal neovascularisation using sucralfate and basic fibroblast growth factor.

PURPOSE: To develop a non-inflammatory model of both acute and chronic angiogenesis in the rabbit cornea using a known directly angiogenic cytokine. METHODS: Pellets made of the slow-release polymer Hydron (polyhydroxyethylmethacrylate) and containing sucralfate and/or basic fibroblast growth factor (basic-FGF) were implanted into rabbit corneas. The neovascular response to the implantation of pellets containing basic-FGF alone, sucralfate alone or a titration of basic-FGF in the presence of a constant amount of sucralfate was measured. The role of inflammation in the neovascular response was also investigated. RESULTS: The addition of sucralfate to the pellets led to the sustained release of basic-FGF resulting in a predictable and aggressive neovascular response with a low dose of basic-FGF that by itself was unable to elicit neovascularisation. At a dose of 500 ng per pellet, approximately one-third of the surface area of the cornea was vascularised within eight days of implantation. Minimal or no vascularisation occurred with the same dose of basic-FGF without sucralfate. While this dose of basic-FGF induced corneal oedema, only minimal inflammation was observed and the response was unaffected by ionising radiation. A less aggressive though still robust neovascular response with no or only minimal oedema was observed when the dose was lowered to 50 ng of basic-FGF per pellet. Some induced vessels persisted for more than three months. CONCLUSION: This is an inexpensive in vivo model of angiogenesis with the advantages of the neovascularisation being aggressive, predictable, persistent, unassociated with an obvious inflammatory response and induced by the sustained release of an agent known to have a direct stimulatory action on endothelial cells.

Acute Disease↗

PubMedDate not supplied

Treatment of inferior oblique muscle overaction with myectomy or with anterior transposition.

This paper presents a comparative study of the effectiveness of myectomy and anterior transposition in the treatment of inferior oblique muscle overaction. We operated 160 patients with overaction of the inferior oblique muscle. Eighty patients (148 eyes) were operated by myectomy at the insertion and 80 patients (151 eyes) by anterior transposition of the insertion of the inferior oblique near the temporal side of the insertion of the inferior rectus muscle. Comparison of the two methods, using the chi-squared test, showed that: 1) both surgical procedures were equally effective (chi 2 = 0.26) for correcting overaction of the inferior oblique muscle and V-phenomenon; 2) weakening of the inferior oblique muscle of both eyes was almost always required (in 115 out of 116 cases) in cases with V-phenomenon and often (24 out of 44 cases) in cases of congenital paresis of the superior oblique muscle. We conclude that both procedures are equally effective and equally easy to perform.

Adolescent↗