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Biomedical subjects

M A Zarbin

Publications and source records attributed to M A Zarbin.

At least 37 records · Page 2Linked to original sources
PubMed1998

Choroidal neovascular membranes: treatment with reirradiation.

PURPOSE: To evaluate re-treatment with an additional course of low-dose irradiation in patients with progressive or recurrent choroidal neovascular membranes (CNVMs). MATERIALS AND METHODS: Ten patients who had received 14 Gy of external-beam radiation therapy in seven fractions for subfoveal CNVMs were found to have recurrent or persistent neovascularization at follow-up. They received an additional 15 Gy of radiation therapy administered in five daily fractions with a standard lens-sparing technique. Before reirradiation, visual acuity ranged from 20/80 to counting fingers. The median time between radiation courses was 6.5 months (range, 2-16 months). After re-treatment, the patients were followed up with angiography and visual field testing. The median follow-up was 18.5 months (range, 12-21 months). RESULTS: Eight of 10 patients (80%) maintained their visual acuity at 1 year and three of seven (43%) at 18 months. Visual acuity was stabilized in five of the 10 patients at their last follow-up. No acute or late side effects of irradiation were noted. CONCLUSION: Additional radiation therapy in selected patients with CNVMs who have failed to benefit from previous irradiation is well tolerated and appears to stabilize the disease process in a substantial proportion of these patients.

Aged↗
PubMed1998

Preparation and transplantation of photoreceptor sheets.

PURPOSE: Photoreceptor (PR) transplantation may be a treatment for blindness secondary to PR degeneration. We studied different technical aspects of PR-sheet preparation. METHODS: Geographic variation in the thickness of the cat PR layer (from the outer segments to the outer plexiform layer) and inner retina (width of the remainder of the retina) was studied. PR sheets (cat and human) were prepared through gelatin embedding and subsequent vibratoming or excimer laser ablation. Cat PR sheets were evaluated after transplantation. RESULTS: The thickness of the cat PR layer and inner retina varied in different regions. The superior central retina, including the area centralis, was thickest (PR layer: 115-123 microm, entire retina: 225-230 microm, in fixed tissue). The peripheral retina was approximately 40% thinner than the center. Fresh retina was approximately 7.9% thicker than the fixed retina. Both vibratomy and excimer laser ablation removed the inner retina, leaving a PR-layer sheet with good morphology. To produce good quality PR sheets with vibratomy, use of different gelatin concentrations (2% to 35%) at various stages of sheet preparation was crucial. To produce PR sheets of uniform thickness with excimer laser ablation, control of fluid on the retinal surface was critical. Twenty-four hours after PR transplantation surgery, donor PR cells were well oriented and in close contact with host retinal pigment epithelial cells. Gelatin supporting the transplant dissolved as early as 100 min after surgery. CONCLUSIONS: We confirmed and expanded the work of previous investigators and showed that cat and human PR sheets can be manufactured using vibratomy or excimer laser ablation. This preparation provides a well oriented and organized PR cell layer after transplantation.

Animals↗
PubMed1997

Clinicopathological correlation of an excised choroidal neovascular membrane in pseudotumour cerebri.

AIMS/BACKGROUND: To correlate the histopathology of an excised choroidal neovascular membrane (CNV) with the clinical and angiographic findings in a 32-year-old woman with pseudotumour cerebri and a peripapillary CNV with subfoveal extension. METHODS: The patient's visual acuity was assessed by individuals experienced in low vision refraction and who were not members of the surgical team. The CNV was excised via a conventional three port vitrectomy with subretinal dissection. The excised tissue was studied with light and electron microscopy. Preoperative and serial postoperative fluorescein angiograms (FAs) and fundus photographs were obtained to study the dissection bed. RESULTS: One week after surgery, the FA showed mottled subfoveal choriocapillaris perfusion. Three weeks after surgery, this area showed retinal pigment epithelium (RPE) atrophy clinically, and the FA showed choriocapillaris non-perfusion. Six months after surgery, the area of RPE atrophy and the corresponding area of choriocapillaris non-perfusion had expanded. Histologically, the excised CNV disclosed hyperplastic RPE, fibrovascular tissue, and no choriocapillaris. Fragments of RPE basement were present along the external edge of the specimen. The patient's visual acuity did not improve significantly after surgery. CONCLUSIONS: Choriocapillaris non-perfusion can develop even in young patients following CNV excision. In this particular case, it is believed that choriocapillaris atrophy was caused by incomplete ingrowth of RPE into the dissection bed following RPE removal with CNV excision. As far as is known, this is the first report describing the results of surgery for CNV secondary to papilloedema associated with pseudotumour cerebri.

Adult↗
PubMed1997

Decreased choriocapillaris perfusion following surgical excision of choroidal neovascular membranes in age-related macular degeneration.

AIMS/BACKGROUND: To evaluate macular changes following surgical excision of subfoveal choroidal neovascular membranes (CNVs) in age-related macular degeneration (AMD). METHODS: The clinical records, fluorescein angiograms, and CNV histopathology of 12 patients with AMD who underwent surgical excision of subfoveal CNV were reviewed. RESULTS: New areas of decreased choriocapillaris perfusion were noted by fluorescein angiography in the previous location of the CNV in 8/12 (75%) cases. Surgically excised tissue contained retinal pigment epithelium (RPE) in 11/11 specimens and choriocapillaris in 1/11 specimen studied. CONCLUSIONS: Choriocapillaris atrophy may partly underlie the limited visual outcome following subfoveal surgery for AMD. Abnormal choriocapillaris perfusion following CNV excision may be due to pre-existing choriocapillaris atrophy, to choriocapillaris damage or removal at the time of surgery, or to RPE removal at surgery with abnormal RPE repopulation of the dissected area and subsequent choriocapillaris degeneration.

Aged↗
PubMed1997

Clinicopathologic correlation of localized retinal pigment epithelium debridement.

PURPOSE: To characterize changes in the retina, retinal pigment epithelium (RPE), and choriocapillaris with fluorescein angiography (FA) and histology after hydraulic or abrasive RPE debridement in 26 domestic short-haired cats. METHODS: Hydraulic debridement was produced by injecting balanced salt solution forcefully into the subretinal space. For abrasive debridement, RPE were removed with a silicone-tipped cannula after creating a localized retinal detachment. The FAs were performed after surgery, and tissue was prepared for light microscopy (LM) and scanning electron microscopy (SEM). RESULTS: Sixty-seven blebs were examined by FA 1 hour after surgery, and RPE debridement was confirmed by SEM or LM in 15 blebs from 10 animals. Hyperfluorescence and variable central fluorescein leakage were seen 1 week after surgery in 52 of 53 blebs (which includes all 27 blebs from the 1-week timepoint and 26 of 29 blebs from the 4-week timepoint that were studied by FA 1 week after surgery). Choriocapillary filling delays were seen in no hydraulic debridements, but in 11 of 14 abrasive blebs, especially in areas showing leakage late in the angiogram. In 1 of 13 hydraulic and 12 of 14 abrasive debridements, areas of late dye leakage had no RPE with outer retinal degeneration. At the 4-week timepoint, 1 of 17 hydraulic and 10 of 12 abrasive debridements had foci of delayed or absent choriocapillary perfusion by FA, with degenerated outer retina, no RPE, and choriocapillary atrophy by histologic analysis. CONCLUSIONS: Abrasive debridement is more commonly associated with abnormal FAs and with incomplete RPE repopulation, choriocapillaris atrophy, and outer retinal degeneration than is hydraulic debridement. This clinicopathologic study may give insight into FA interpretation after choroidal neovascular membrane removal in human patients.

Animals↗
PubMed1996

Treatment of presumed fungal endophthalmitis with oral fluconazole.

Amphotericin B is the usual treatment for fungal endophthalmitis, but its toxicity and lack of oral bioavailability may limit its use in some patients. The authors report the successful management of two cases of presumed metastatic fungal endophthalmitis with oral fluconazole, a bis-triazole compound with a broad antifungal spectrum.

Administration, Oral↗
PubMed1993

Migration of solid silicone encircling element through four rectus muscles.

Anterior migration of an encircling element through a rectus muscle is an unusual complication of scleral buckling surgery. We describe two patients with migration of a solid silicone encircling element through the insertions of all four rectus muscles after retinal detachment surgery. Buckle migration was associated with elevated intraocular pressure and glaucomatous optic atrophy. Rectus muscle function was preserved in both patients. Despite transsection of the anterior ciliary blood supply, anterior segment ischemia did not develop.

Adult↗
PubMed1992

Retinal manifestations of ocular lymphoma (reticulum cell sarcoma).

BACKGROUND: Diagnosis and treatment of ocular large cell lymphoma may lessen visual loss and prolong life. Although reports in the literature have described retinal infiltrates in eyes with large cell lymphoma, they have focused on the more prominent vitreous and subretinal pigment epithelial findings. Eyes with retinal infiltrates and hemorrhagic retinal necrosis are usually believed to harbor a microbial infection. The authors describe 5 patients, aged 57 to 85 years, with ocular lymphoma in whom the most prominent initial findings were in the retina. METHOD: Patients presented with findings suggestive of an infectious retinal necrosis. When the initial therapy failed, investigators performed a vitreous biopsy. Two patients had a concomitant retinal biopsy. Radiation therapy was given to four patients. RESULTS: All five patients had vitreous cells. Three patients had prominent perivascular exudate. Four patients had grayish-white retinal infiltrates, and three patients had associated retinal hemorrhage. Three patients had subretinal small white spots. An edematous thickened retina developed in three patients, and hemorrhagic retinal necrosis developed in three patients. The initial diagnosis was believed to be acute retinal necrosis (ARN) in three patients, toxoplasmosis in one patient, and frosted branch angiitis in one patient. Vitreous biopsy was positive in two patients but negative in three patients. In two of these three patients, the diagnosis was established by retinal biopsy. CONCLUSION: Ocular lymphoma should be considered in the differential diagnosis of retinal vasculitis or necrotizing retinitis in a middle-aged or older patient. Retinal biopsy may be helpful in establishing the diagnosis.

Aged↗
PubMed1991

Fluorescence of blood-stained cornea.

Corneal blood staining represents deposition of hemoglobin and its breakdown products within the cornea. Pathologic examination of these corneas typically reveals degenerating endothelial cells and keratocytes. These degenerative changes have typically been attributed to the blunt trauma itself or to toxicity of the erythrocytic debris (a "localized hemosiderosis"). Another possible mechanism for this injury, however, is porphyrin-induced photosensitivity. Examination of frozen sections of an acutely blood-stained human cornea demonstrated fluorescence within all layers of the cornea, similar to that seen with hematoporphyrin derivative. The production of cytotoxic oxygen species within the blood-stained cornea exposed to light may contribute to endothelial and keratocyte degeneration. Limiting light exposure of blood-stained corneas or eyes with hyphemas might theoretically reduce light-induced and porphyrin-mediated toxicity.

Adult↗
PubMed1991

Dissection of epiciliary tissue to treat chronic hypotony after surgery for retinal detachment with proliferative vitreoretinopathy.

Surgery was performed on nine eyes of nine consecutive patients with chronic postoperative hypotony after prior vitreous surgery for retinal detachment and proliferative vitreoretinopathy. The operation included lysis of adhesions between the iris and the ciliary processes and removal of lens remnants and other fibrocellular tissue covering and/or causing traction on the pars plicata. The preoperative intraocular pressure was less than or equal to 5 mm Hg in all eyes, and the final postoperative intraocular pressure was 8 to 20 mm Hg in five eyes, 6 mm Hg in one eye, 4 mm Hg in one eye, and 0 mm Hg in two eyes. Minimum postoperative follow-up was 7 months and average follow-up was 10 months. This form of surgery to uncover and minimize traction on the ciliary body substantially increased the intraocular pressure in most of the treated cases and suggests that iridociliary adhesions and tissue proliferation covering and/or causing traction on the ciliary processes account for chronic postoperative hypotony in some cases after extensive surgery for proliferative vitreoretinopathy.

Aged↗
PubMed1991

Benzodiazepine receptors in the eye.

Central and peripheral benzodiazepine receptors were localized in the rat, monkey, and human eye by in vitro autoradiography. Central benzodiazepine binding sites, visualized with 3H-R015-1788, were enriched in the inner plexiform layer in all three species. Binding sites also were present in the nerve fiber layer, the ganglion cell layer, and in portions of the inner nuclear layer. Peripheral benzodiazepine binding sites, visualized with 3H-PK-11195, were found in the corneal epithelium and endothelium, iris, ciliary epithelium, trabecular meshwork, and throughout the retina. Binding sites for 3H-PK-11195 also were present in the retinal pigment epithelium and choriocapillaris areas and retinal vascular structures.

Aged↗
PubMed1990

Epiretinal membrane contracture associated with macular prolapse.

We treated two patients with annular epiretinal membranes that produced unusual macular morphologic characteristics. Contracture of the membranes caused herniation of macular tissue through a hole in the center of the membrane. The membranes were removed surgically, and ultrastructural analysis disclosed cells with properties resembling myofibroblasts and apparent new vitreous collagen. Contracture of the cellular components probably produced tangential traction on the retina, which caused prolapse of the retinal tissue through a central defect in the membrane.

Child↗
PubMed1990

Anterograde transport of opioid receptors in rat vagus nerves and dorsal roots of spinal nerves: pharmacology and sensitivity to sodium and guanine nucleotides.

We have utilized the technique of in vitro autoradiography to ascertain that opioid receptors are transported in the rat vagus nerve and in the rat dorsal spinal root fibers. In the dorsal roots, opioid receptors accumulated on both sides of the ligatures. In the vagus nerve, a distal accumulation of binding sites was difficult to detect, however, proximal to the ligatures, vagal receptors accumulated in a linear fashion during the first 12 h of ligation. At longer periods after ligation, accumulation was less than expected and the receptors appeared to migrate retrogradely. The receptor transport could be blocked by intravagal colchicine injection and the receptor translocation could be elicited in isolated vagal nerve segments suggesting that the receptors move by fast transport. Sodium chloride, present in the incubation medium, inhibited [3H]dihydromorphine ([ 3H]DHM) binding to receptors adjacent to and far from the proximal aspect of the ligature with IC50's of 42 mM and 51 mM, respectively. The addition of GTP in the incubation medium also inhibited [3H]DHM binding to "proximal" and "far proximal" receptors with IC50's of 0.27 microM and 1.0 microM, respectively. The presence of GTP also inhibited [3H]naloxone ([3H]Nal) binding to "proximal" and "far proximal" receptors with IC50's of 0.34 microM and 0.66 microM, respectively. The transported vagal opioid receptors bound the ligands in a stereospecific manner. Using [3H]DHM, [3H]D-ala2-D-leu5-enkephalin [( 3H]DADL), and [3H]ethylketocyclazocine ([3H]EKC), we found that most of the transported vagal receptors have mu-pharmacology although kappa and delta receptors are present.

Animals↗
PubMed1989

Autoradiographic distribution of forskolin and phorbol ester binding sites in the retina.

We have localized the distribution of [3H]forskolin and [3H]phorbol dibutyrate binding sites autoradiographically in the rat, monkey, and human retina. In the rat and monkey retina, forskolin binding was enriched in the inner plexiform layer, in the inner and outer segments of the photoreceptors, and in the retinal pigment epithelium. In the human retina, forskolin binding sites were uniformly distributed and higher in density. Forskolin binding was also detected over the ciliary body, the ciliary epithelium, and the iris sphincter. The distribution of phorbol ester binding sites was similar in the rat, monkey, and human retina. The inner plexiform layer contained the highest density followed by the inner nuclear and outer plexiform layers, and the ganglion cell layer. In the rat, phorbol ester binding was present in the iris, the ciliary body, and the ciliary epithelium. The monkey and human ciliary body also contained a low density of phorbol ester binding sites.

Animals↗
PubMed1989

The Rieger anomaly concomitant with multiple dental, craniofacial, and somatic midline anomalies and short stature.

An unusual, isolated case of the Rieger anomaly coincident with a multitude of dental, craniofacial, and systemic anomalies is described. Significant dental findings were severe enamel hypoplasia, conical and misshapen teeth, hypodontia, and impactions. Craniofacial disorders were underdevelopment of the maxilla, mandible, and anterior and posterior cranial bases, low-set ears, and a wide nasal bridge. Reported for the first time is the association of this genetic disorder with bilateral microcondyles and bilateral choanal atresia. Embryologic disturbance of the neural crest ectoderm is suspected. The patient also manifested anal atresia, scoliosis, kyphosis, and short stature. A discussion distinguishing this case report from the Rieger syndrome is presented. In addition, the possibility that the patient exhibited a previously unreported syndrome is also considered, and the term Short-F-R-A-M-E is proposed to name this new syndrome.

Abnormalities, Multiple↗
PubMed1988

Endolaser treatment of the ciliary body for severe glaucoma.

Endolaser photocoagulation of the ciliary body was used to treat 42 eyes with severe glaucoma that could not be managed successfully by medical therapy and conventional glaucoma surgery. Follow-up ranged from 6 to 36 months (mean, 13 months). The preoperative intraocular pressure (IOP) ranged from 13 to 76 mmHg (mean, 37 mmHg). The postoperative IOP ranged from 1 to 44 mmHg (mean, 17 mmHg), representing an absolute decrease of 20 mmHg, and a mean decrease of 48%. After one or two (7 eyes) treatment sessions, 11 eyes (26%) had an IOP less than 21 mmHg without medications; 21 eyes (50%) had an IOP less than 21 mmHg with medications; 5 eyes (12%) had an IOP of 21 to 25 mmHg with or without medications; and 5 eyes (12%) had an IOP greater than 25 mmHg. Postoperatively, the number of antiglaucoma medications required was reduced from a mean of 2.8 +/- 0.13 to a mean of 1.4 +/- 0.19. Twenty-three (72%) of 32 patients were able to discontinue carbonic anhydrase inhibitors.

Adolescent↗