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Biomedical subjects

L V Del Priore

Publications and source records attributed to L V Del Priore.

At least 37 records · Page 2Linked to original sources
PubMed1997

Human photoreceptor transplantation in retinitis pigmentosa. A safety study.

OBJECTIVE: To establish the technical feasibility and safety of photoreceptor transplantation in retinitis pigmentosa. METHODS: A sheet of human photoreceptor cells was harvested from 2 human cadaveric eyes with a vibratome and transplanted into the subretinal spaces of 2 patients with advanced retinitis pigmentosa and visual acuity of no light perception by means of submacular surgery techniques. Preoperative and postoperative electrophysiologic testing, fundus photography, fluorescein angiography, and scanning laser ophthalmoscopy were performed. RESULTS: Twelve months after photoreceptor transplantation, the visual acuity of each patient remained no light perception. The temporal edge of the retinotomy in 1 patient was folded but was not associated with a retinal detachment. The patients were not immunosuppressed, and there was no evidence of rejection of the allogeneic transplant. Cystoid macular edema, uveitis, and macular pucker were not observed. CONCLUSION: A sheet of adult human photoreceptor cells can be harvested from human cadaveric eyes and safely transplanted to the subretinal spaces of patients with retinitis pigmentosa without systemic immunosuppression.

Adolescent↗
PubMed1997

Tissue culture of retinal pigment epithelium following isolation with a gelatin matrix technique.

Prior to transplantation of the retinal pigment epithelium, it is necessary to develop techniques to harvest viable retinal pigment epithelium as an organized monolayer. Unfortunately, current techniques result in contraction of the harvested monolayer and coiling of the cell sheets, which hinders successful transplantation. The purpose of this study was to develop a method for harvesting retinal pigment epithelium from eye cups and from tissue culture prior to transplantation. Passage 1 porcine retinal pigment epithelium and native retinal pigment epithelium from fresh porcine eye cups were pretreated with 0.25% edetic acid for 12 minutes and coated with a 100 micron layer of 12% gelatin. Patches of the retinal pigment epithelial cell monolayer were harvested and transferred to culture plates, and cell viability and the ability of the transferred cells to proliferate in culture was determined. Our results demonstrated that retinal pigment epithelium can be harvested from tissue culture and eye cups as an organized monolayer with high efficiency (94.7 +/- 3.5% and 99.7 +/- 0.3% harvesting rates, respectively) and high cell viability (91.3 +/- 2.9% and 89.4 +/- 4.3%, respectively). Cells harvested from tissue culture plates divided and became confluent within 10 to 14 days. Cells harvested from eye cups maintained a differentiated phenotype and migrated outward from the margin of the exoplant. There was no contraction of the retinal pigment epithelial monolayer isolated from either substrate. Thus, we were able to harvest retinal pigment epithelium as an organized monolayer from tissue culture plates and freshly enucleated eyes with edetic acid and gelatin. The harvested cells were viable and proliferated without contraction of the monolayer in vitro.

Animals↗
PubMed1997

Reattachment to a substrate prevents apoptosis of human retinal pigment epithelium.

BACKGROUND: Epithelial cells generally fail to survive in suspension. Harvesting human retinal pigment epithelium (RPE) for transplantation may separate the cells from their extracellular matrix and induce apoptosis. We investigated whether reattachment of RPE to a substrate will prevent apoptosis. METHODS: Second-passage human RPE cells were plated onto tissue culture plastic precoated with extracellular matrix, fibronectin or laminin, uncoated tissue culture plastic, untreated plastic and untreated plastic coated with 4% agarose. Reattachment rates were determined for each substrate 24 h after plating. The TUNEL technique was used to determine apoptosis rates in attached cells, unattached cells and the entire cell population. RESULTS: Attachment rates were as follows: ECM-coated tissue culture plastic-->fibronectin-coated tissue culture plastic-->laminin-coated tissue culture plastic-->uncoated tissue culture plastic-->untreated plastic-->agarose-coated untreated plastic. Apoptosis rates for the entire cell population increased as the RPE cell attachment rate decreased. The proportion of apoptotic cells in the entire population was inversely related to the percent attached cells (r = -0.95). CONCLUSION: Reattachment of harvested RPE to a substrate decreased the rate of RPE apoptosis in vitro. RPE cells which are removed from their substrate prior to transplantation must reattach rapidly to a substrate to prevent apoptosis.

Apoptosis↗
PubMed1997

Endogenous Ochrobactrum anthropi endophthalmitis.

PURPOSE: To describe bilateral endogenous endophthalmitis caused by Ochrobactrum anthropi in a partially immunosuppressed patient who had undergone central venous access for hyperalimentation and home intravenous therapy. METHODS: Case report. RESULTS: Blood cultures were positive for O anthropi. Vitreous cultures grew a gram-variable bacillus. The patient's ocular and systemic condition markedly improved after intravitreal antibiotics and systemic ciprofloxacin. CONCLUSIONS: Ochrobactrum anthropi may cause endogenous endophthalmitis in patients with a history of indwelling catheters for venous access or other permanent medical devices.

Aged↗
PubMed1997

Perfusion of the subfoveal choriocapillaris affects visual recovery after submacular surgery in presumed ocular histoplasmosis syndrome.

PURPOSE: To determine the relationship between the visual result and perfusion of the subfoveal choriocapillaris after surgical excision of subfoveal neovascularization in presumed ocular histoplasmosis syndrome. METHODS: We reviewed the records of 38 eyes of 37 patients with gradable postoperative fluorescein angiograms and color photographs after surgical excision of a subfoveal neovascular membrane in presumed ocular histoplasmosis syndrome. The postoperative photographs and fluorescein angiograms were graded in a masked fashion for the presence of perfusion of the subfoveal choriocapillaris. We used preoperative and postoperative best-corrected visual acuities to determine the correlation between postoperative perfusion of the subfoveal choriocapillaris and both final visual acuity and visual improvement after surgery. RESULTS: After surgery, the subfoveal choriocapillaris was perfused in 24 of the 38 eyes (63%) and nonperfused in 14 (37%). Best-corrected visual acuity improved by at least 2 Snellen lines in 17 of the 24 perfused eyes (71%) and two of the 14 nonperfused eyes (14%) (P = .0089). Best-corrected visual acuity of 20/100 or better was achieved in 18 of the perfused eyes (75%) and four nonperfused eyes (29%) (P = .0076). CONCLUSION: Both final visual acuity and improvement in visual acuity were correlated with postoperative perfusion of the subfoveal choriocapillaris in patients with presumed occular histoplasmosis syndrome. Development of techniques to maintain or reestablish perfusion of the subfoveal choriocapillaris after surgery may improve visual outcome in these eyes.

Capillaries↗
PubMed1997

Effect of mitomycin-C on human retinal pigment epithelium in culture.

PURPOSE: To determine the effect of mitomycin-C on confluent and non-confluent human retinal pigment epithelium (RPE) in tissue culture. METHODS: The effect of mitomycin-C on confluent RPE was determined by treating first passage confluent cells with 0.01, 0.1, 1, 10, 100 or 1000 micromolar (microM) mitomycin-C for 1, 3, or 7 days. The cell viability after treatment was determined by using an esterase stain. The effect of mitomycin-C on proliferating RPE was determined by incubating non-confluent cells with the above concentrations of mitomycin-C for 20 min, 1 hour or 24 hours. RESULTS: Mitomycin-C can be toxic to a confluent RPE monolayer, and the LD50 is 421, 28.8 or 0.0632 microM when cells are continually exposed to mitomycin-C for 1, 3 or 7 days, respectively. Exposure to mitomycin-C at concentrations > or = 10 microM for 20-60 min significantly inhibits proliferation of non-confluent RPE. A 24 hour exposure of RPE to 1 microM mitomycin-C markedly inhibits proliferation of non-confluent RPE with minimal toxicity to confluent RPE. CONCLUSIONS: Since exposure of human RPE to mitomycin-C for 24 hours can inhibit cell proliferation at concentrations which are well-tolerated by confluent RPE, mitomycin-C may be a suitable agent for inhibiting RPE proliferation in vivo.

Cell Division↗
PubMed1997

Harvest and storage of adult human retinal pigment epithelial sheets.

PURPOSE: To describe a method for the harvesting and storing of intact viable sheets of adult human retinal pigment epithelial (RPE) cells. METHODS: Adult human RPE cells were harvested as intact sheets from 21 cadaver eyes, using the enzyme Dispase. The sheets were embedded in 50% gelatin containing 300 mM sucrose and stored at 4 degrees C. The viability of the cells, as well as their ability to proliferate in vitro, was studied for 96 hours after harvesting. Light microscopy (LM), transmission (TEM) and scanning electron microscopy (SEM) were performed to determine the integrity and ultrastructural features of the cells. Microbiologic culture of the harvested sheets was performed to exclude contamination. RESULTS: LM, TEM and SEM showed intact RPE cells with well-developed microvilli, basal infoldings and intercellular connections. The initial viability of intact RPE sheets was 86%, with a progressive decline in viability with increased storage time. Cells harvested within 24 hours after death maintained greater viability than those harvested after 24 hours (p < 0.05). Harvested RPE cells were free of microbial contamination and rapidly proliferated when cultured in vitro. CONCLUSION: Intact sheets of adult human RPE can be isolated using the enzyme Dispase. The cells appeared suitable for retinal transplantation if harvested within 24 hours of death and maintained 82% viability for as long as 48 hours if stored at 4 degrees C.

Adolescent↗
PubMed1997

Nanophthalmic uveal effusion managed with scleral windows and topical mitomycin-C.

The authors treated a 38-year-old man with nanophthalmic uveal effusion with scleral windows and local application of mitomycin-C. The patient underwent two separate surgical procedures, involving placement of scleral windows in all four quadrants and topical application of mitomycin-C in one quadrant. Episcleral scarring led to closure of scleral windows in all quadrants except one quadrant where mitomycin-C was applied during the first surgery. The uveal effusion resolved following the second surgery. No complications related to mitomycin-C were observed. Topical mitomycin-C may be a useful adjunct in the surgical management of uveal effusion syndrome.

Administration, Topical↗
PubMed1997

Reattachment of cultured human retinal pigment epithelium to extracellular matrix and human Bruch's membrane.

PURPOSE: To determine the mechanism of reattachment of harvested human retinal pigment epithelium (RPE) to RPE-derived extracellular matrix and Bruch's membrane. METHODS: Confluent first-to third-passage human RPE were harvested from tissue culture and plated onto RPE-derived extracellular matrix or human Bruch's membrane exoplants denuded of cells by treatment with 0.02 N ammonium hydroxide. The authors measured RPE reattachment to uncoated surfaces or surfaces precoated with extracellular matrix proteins (fibronectin, laminin, vitronectin, or type IV collagen), antibodies to extracellular matrix-proteins, or the synthetic peptide RGDS (arginine-glycine-aspartate-serine). Some RPE were pretreated with anti-beta 1 integrin antibodies before plating onto either substrate. RESULTS: Coating the surface of either RPE-derived extracellular matrix or Bruch's membrane with fibronectin, laminin, vitronectin, or type IV collagen increased the RPE attachment rate. Exposing RPE to anti-beta 1 integrin antibodies or RGDS or precoating the surface with antibodies to fibronectin, laminin, vitronectin, or type IV collagen decreased the RPE attachment rate to both surfaces. The RPE attachment rate to Bruch's membrane was lower when the exoplants were harvested from the macula of older (age, 70 to 90 years) versus younger (age, 30 to 40 years) persons (52.4 +/- 3.6% versus 64.3 +/- 3.5%, respectively; P < 0.05). CONCLUSIONS: The attachment of cultured human RPE cells to human Bruch's membrane or to RPE-derived extracellular matrix is mediated by an interaction between the beta 1-subunit of integrin on the RPE surface and ligands in the extracellular matrix that include laminin, fibronectin, vitronectin, and type IV collagen. The lower rate of RPE reattachment to the macula from older human cadaveric eyes may have implications for studies aimed at RPE transplantation in elderly persons.

Adhesiveness↗
PubMed1996

Density-dependent growth regulation of pig retinal pigment epithelial cells in vitro.

BACKGROUND: Transplantation of the retinal pigment epithelium (RPE) involves delivering donor RPE onto a bare area of host Bruch's membrane that is surrounded by a confluent monolayer of RPE. We investigated the effects of different plating densities and the presence of an adjacent confluent monolayer on the growth characteristics and final morphology of pig RPE in vitro. METHODS: In single-well experiments, porcine RPE were plated in 24-well plates at densities varying from 1 to 75 cells/mm2. Triplicate plates were counted on the 3rd and 10th days after plating and at confluence. A multiwell chamber was built to allow cells plated at different densities to be bathed with conditioned media from adjoining wells. RESULTS: In single-well experiments, plating at low densities increased the time to reach confluence and resulted in fewer, larger and more fusiform RPE at confluence. In multiwell experiments, the growth rate of cells plated at low density decreased as the amount of high-density medium increased in communicating wells and led to smaller, rounder cells at confluence. The presence of low-density RPE in adjoining wells increased the growth rate of RPE plated at high density and produced fewer, larger and more fusiform cells at confluence. Newly plated RPE grew more slowly when confluent monolayers of RPE were present in adjoining wells. CONCLUSIONS: Plating density is a critical factor in determining the growth rate and the final morphology of RPE in tissue culture. The presence of a neighboring confluent monolayer of RPE inhibits the growth rate of newly plated RPE in vitro.

Animals↗
PubMed1996

Retinal pigment epithelial debridement as a model for the pathogenesis and treatment of macular degeneration.

PURPOSE: To determine the effects of the absence of the retinal pigment epithelium on the choriocapillaris and outer retina by performing retinal pigment epithelial cell debridement with mitomycin C to inhibit cell proliferation pharmacologically in the porcine eye. METHODS: A pars plana vitrectomy was performed in 12 eyes, and two neurosensory retinal detachments per eye were created by injecting 10(-3) mg/ml mitomycin C and 0.25% edetic acid into the subretinal space. Twenty minutes later, the retinal pigment epithelium was debrided, and the retina was reattached with a fluid-gas exchange. RESULTS: Bruch's membrane was devoid of native retinal pigment epithelium, and the choriocapillaris was patent immediately after debridement. No proliferation of the retinal pigment epithelium occurred 1 week after debridement, and choriocapillaris atrophy was present beneath areas of Bruch's membrane that were devoid of retinal pigment epithelium. Four weeks postsurgery, choriocapillaris atrophy persisted in all debrided blebs, although unpigmented retinal pigment epithelium repopulated portions of Bruch's membrane in one of three blebs. Outer retinal atrophy was present in areas of Bruch's membrane with no retinal pigment epithelium and no choriocapillaris 4 weeks postsurgery. The choriocapillaris was patent in areas of mitomycin C injection without debridement. CONCLUSION: Absence of the retinal pigment epithelium leads to atrophy of the choriocapillaris within 1 week after surgery. This finding provides an animal model to study transplantation of retinal pigment epithelium onto bare patches of Bruch's membrane in age-related macular degeneration and other diseases and provides insight into the pathogenesis of nonexudative age-related macular degeneration.

Animals↗
PubMed1996

Treatment of persistent glaucoma secondary to periocular corticosteroids.

PURPOSE: To describe two patients with uveitis who developed increased intraocular pressure that was unresponsive to maximum medical therapy eight and 13 months after periocular injection of triamcinolone acetonide. METHODS: Excised periocular tissue was analyzed for corticosteroid activity by gas chromatography and mass spectrometry. RESULTS: Excision of the periocular tissue, which contained visible triamcinolone acetonide, resulted in a normal intraocular pressure within 14 days in both patients. Analysis of the excised tissue disclosed residual corticosteroid in one of the two patients. CONCLUSION: Removal of periocular tissue containing injected corticosteroids may facilitate the management of patients developing increased intraocular pressure unresponsive to maximum medical therapy.

Anti-Inflammatory Agents↗
PubMed1996

Uveal effusion syndrome associated with primary pulmonary hypertension and vomiting.

PURPOSE: We treated a 69-year-old woman with bilateral uveal effusions associated with primary pulmonary hypertension, congestive heart failure, and vomiting. METHODS: The patient underwent ophthalmoscopic, echocardiographic, and fluorescein angiographic examinations. RESULTS: Increased venous pressure caused by congestive heart failure and vomiting was implicated as the cause of bilateral uveal effusions. The uveal effusions responded well to systemic furosemide. CONCLUSION: Primary pulmonary hypertension with right-sided congestive heart failure and vomiting can lead to the development of uveal effusions.

Aged↗
PubMed1996

Correlation between scanning laser ophthalmoscope microperimetry and anatomic abnormalities in patients with subfoveal neovascularization.

PURPOSE: The purpose of the study is to identify the anatomic abnormalities associated with an absolute scotoma and the location and stability of fixation in patients with subfoveal neovascularization in age-related macular degeneration, presumed ocular histoplasmosis syndrome, and other disorders. METHODS: Scanning laser ophthalmoscope microperimetry was superimposed on color fundus photographs and fluorescein angiograms of 21 eyes with subfoveal neovascular membranes secondary to age-related macular degeneration (14 eyes) and presumed ocular histoplasmosis syndrome (7 eyes). The authors determined the location and the area occupied by the absolute scotoma and each of the following subretinal lesions: subretinal hemorrhage, neurosensory retinal detachment, retinal pigment epithelial (RPE) atrophy, RPE hyperplasia, atrophy of the choriocapillaris, hard exudates, and the subfoveal neovascular membrane. The area of absolute scotoma determined by scanning laser ophthalmoscope microperimetry was superimposed on the anatomic lesions. The authors calculated the relative risk ratio (RR) of an absolute scotoma occurring in regions corresponding to each anatomic abnormality, and determined the preferred location and stability of fixation in each eye. RESULTS: An absolute scotoma was present in areas of chorioretinal scar (RR = 107.61), RPE atrophy (RR = 9.97), subretinal hemorrhage (RR = 2.88), and the neovascular membrane (RR = 1.86). Fixation was stable in all patients with presumed ocular histoplasmosis syndrome but only 29% of patients with age-related macular degeneration. Fifty-five percent of patients with stable fixation fixated over an area of RPE hyperplasia. CONCLUSION: The relative risk of an absolute scotoma is highest over areas of chorioretinal scars, RPE atrophy, subretinal hemorrhage, and the neovascular membrane. Fixation is more stable in patients with subfoveal neovascularization from presumed ocular histoplasmosis syndrome than with age-related macular degeneration and frequently is present over an area of RPE hyperplasia.

Adult↗
PubMed1996

Postoperative abnormalities of the choriocapillaris in exudative age-related macular degeneration.

AIMS: To study the incidence and possible cause of abnormalities of the subfoveal choriocapillaris after surgical excision of subfoveal choroidal neovascularisation in age-related macular degeneration (ARMD). METHODS: The postoperative fluorescein angiograms and colour photographs of 29 eyes of 29 patients were reviewed after surgical excision of subfoveal choroidal neovascularisation in exudative ARMD. Preoperative and postoperative fluorescein angiograms were examined for perfusion of the subfoveal choriocapillaris. The excised subfoveal choroidal neovascular membranes from eight eyes that demonstrated postoperative abnormalities of the choriocapillaris were embedded in paraffin, serially sectioned and examined for the presence of the choriocapillaris. RESULTS: Postoperative fluorescein angiograms revealed abnormal perfusion of the subfoveal choriocapillaris in 26 of the 29 eyes (90%) and in all eight eyes that had histopathological examination of the surgical specimens. Examination of serial sections demonstrated that none of the excised neovascular membranes contained choriocapillaris. CONCLUSIONS: Abnormal perfusion of the subfoveal choriocapillaris was frequently present following removal of the subfoveal neovascular membrane in ARMD. The histopathological study demonstrated that abnormalities of the choriocapillaris were not due to removal of the choriocapillaris at the time of surgery.

Aged↗
PubMed1996

En bloc transfer of extracellular matrix in vitro.

PURPOSE: Extracellular matrix (ECM) plays a major role in the development and regeneration of various epithelial cells including retinal pigment epithelium (RPE), and attachment to ECM inhibits RPE apoptosis. Transplantation of ECM prior to the transplantation of RPE may modulate the survival and subsequent proliferation of transplanted RPE. Thus, we have developed a technique to harvest and transfer native ECM produced by bovine, porcine and human cell lines. METHODS: ECM was prepared by treating a confluent monolayer of cells with 0.02 N ammonium hydroxide. The ECM was then coated with a thin 100 mu layer of 12% gelatin and cooled to 4 degrees C. Patches of the ECM were isolated and transferred to another culture plate. The transferred ECM was characterized by immunohistochemistry. We determined the ability of cultured RPE to reattach to the harvested ECM, and the ability of the harvested ECM to inhibit RPE apoptosis. RESULTS: Native ECM can be transferred to another location en bloc with this technique. Immunohistochemistry demonstrates that the transferred ECM contains fibronectin, laminin and collagen IV. The reattachment rate of human RPE to each type of transferred ECM is higher (83.6 +/- 2.8%) than RPE reattachment to bare tissue culture plastic (57.6 +/- 9.8%). The apoptotic rate of attached RPE cells on transferred bovine corneal endothelial ECM (4.3 +/- 1.4%) is lower than their apoptotic rate on bare plastic (69.3 +/- 4.1%). The apoptotic rates of unattached cells are 80.3 +/- 4.4% on transferred bovine corneal endothelial ECM and 79.2 +/- 3.4% on bare plastic. CONCLUSIONS: We conclude that ECM produced by various cell lines can be harvested and transferred by this technique. The transferred ECM promotes cell reattachment and inhibits RPE cell apoptosis. Harvesting and transfer of ECM at the time of RPE transplantation may inhibit apoptosis and promote survival of the transplant.

Animals↗