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Biomedical subjects

G J Jaffe

Publications and source records attributed to G J Jaffe.

At least 73 records · Page 4Linked to original sources
PubMed1994

Lightning maculopathy. A case report.

BACKGROUND: Lightning can cause a number of ocular complications. A case involving a patient who developed a cataract and reversible maculopathy in both eyes after being struck by lightning is reported. METHODS: The patient was evaluated for cataract and macular edema by ophthalmoscopic examination, fluorescein angiography, and potential acuity meter. RESULTS: Maculopathy developed that was characterized initially by a retinal cyst with surrounding edema. Later, the lesions evolved to simulate a full-thickness hole. These lesions subsequently resolved, and the patient's visual acuity improved to 20/20 in each eye after cataract extraction. CONCLUSION: Because the visual prognosis for lightning-induced maculopathy is potentially different than that for full-thickness macular holes, careful retinal examination is essential in the preoperative workup.

Adult↗
PubMed1994

Inhibition of cultured human RPE cell proliferation and lysyl hydroxylase activity by hydroxy derivatives of minoxidil.

PURPOSE: To examine the antiproliferative and lysyl hydroxylase suppressing effects of 3'-hydroxyminoxidil and 4'-hydroxyminoxidil, derivatives of minoxidil devoid of the antihypertensive effect, on human retinal pigment epithelial (RPE) cells in culture. METHODS: Subconfluent and confluent cultures of RPE cells, exposed to 0.01 to 5 mM 3' or 4'-hydroxyminoxidil for 15 minutes to 7 days, were examined for proliferation, viability, and morphologic changes. Lysyl hydroxylase activity in confluent cultures exposed to 1 mM 3'- or 4'-hydroxyminoxidil was determined by measuring the amount of 3H2O released from L-(4,5-3H)lysine-labeled unhydroxylated procollagen substrate after vacuum distillation. RESULTS: Both compounds inhibited the proliferation of subconfluent cultures of RPE cells in a dose-dependent fashion. The 50% effect occurred at 0.25 mM for 3'-hydroxyminoxidil and 0.5 mM for 4'-hydroxyminoxidil. The antiproliferative effect was detectable within 24 hours, required a minimum 1-hour exposure, and persisted even after the drug was removed from the culture medium. Cell viability experiments provided no evidence for toxicity. In contrast, the number of cells at confluent density was not affected. Both 3'-hydroxyminoxidil and 4'-hydroxyminoxidil suppressed lysyl hydroxylase activity by 72%. CONCLUSIONS: The structure of minoxidil can be altered to reduce the antihypertensive activity while preserving the antiproliferative and lysyl hydroxylase suppressing effects. The hydroxy derivatives of minoxidil may be useful in the treatment of proliferative vitreoretinopathy, a disease with unwanted proliferation of RPE cells.

Cell Division↗
PubMed1994

Activin expression by cultured human retinal pigment epithelial cells.

PURPOSE: To determine whether human retinal pigment epithelial (hRPE) cells produce activin, a growth factor in the transforming growth factor beta family, and to characterize growth regulatory effects of activin on retinal pigment epithelium. METHODS: mRNA expression was examined using polymerase chain reaction with primers specific for the beta A and beta B chains of activin and by slot blot analysis with a probe specific for the beta A chain. Protein localization was determined immunocytochemically using antibodies specific for the beta A chain of activin and intact activin A. The effect of activin A on DNA synthesis was studied by measuring (3H) thymidine incorporation after cells were exposed to recombinant human activin A (rhA). Growth regulatory effects of rhA on hRPE cells were examined with cell growth assays. RESULTS: beta A mRNA was expressed constitutively in 8/8 cells lines tested. beta B mRNA was not expressed in any of the six cell lines tested but was expressed in human ovarian granulosa cell controls. Positive immunostaining was observed for both the beta A chain and intact activin A. (3H) thymidine incorporation was inhibited 44% (P < 0.025), 45% (P < 0.025), and 44% (P < 0.015) when RPE cells were exposed to 100 ng/ml rhA and grown in serum-free medium, medium with 0.5% serum, and 1% serum, respectively. Cell growth was inhibited 33.2% (P = 0.0001) after RPE cells were exposed to 100 ng/ml rhA for 8 days. CONCLUSIONS: These results suggest that activin A can act as an autocrine-paracrine growth regulator in RPE cells and may help control cellular growth in ocular development and proliferative eye disease.

Activins↗
PubMed1993

Monensin enhances the cytotoxic effect of antitransferrin receptor immunotoxin on cultured RPE cells.

The effect of monensin on the cytotoxic effect of antitransferrin receptor immunotoxin (IT) was determined on cultured, human retinal pigment epithelial (hRPE) cells. Human RPE cells were treated with 0.1-10,000 ng/ml IT with and without 0.01-0.1 microM monensin, a lysosomotropic reagent that can influence IT activity. Monensin (0.01 microM) shortened the onset of cell kill with IT (10,000 ng/ml) from 48 to 24 hours (p = 0.0016). Although 0.01 microM monensin alone was not cytotoxic to hRPE cells, a single 7-day treatment with monensin caused up to a 4.1-fold increase in antiproliferative potency of IT on proliferating hRPE cells (p < or = 0.0001). Enhancement was obtained with only a 1-hour exposure to 0.1 microM monensin (p = 0.0001). In contrast, IT (0.1-10,000 ng/ml) combined with monensin (0.01 microM) had minimal effect on density-arrested cells. IT with or without monensin did not inhibit proliferation of Rhesus monkey RPE cells. Our results indicate that monensin enhances the selective cytotoxic effect of IT on proliferating hRPE cells in culture.

Animals↗
PubMed1993

The antiproliferative effect of a transferrin-toxin on human retinal pigment epithelial cells and rabbit fibroblasts.

PURPOSE: To determine the effect of a rabbit transferrin conjugated to recombinant ricin A chain (Tfr-rRA) and the carboxylic ionophore monensin on proliferating and density-arrested human retinal pigment epithelial cells and rabbit dermal fibroblasts. METHODS: Cells were seeded on 24-well plates at 20,000 cells/cm2 and exposed to Tfr-rRA (0.1-10,000 ng/ml) with or without monensin (0.01 microM), and with or without human transferrin (65.7 mg/l) for 5 minutes to 7 days. Cells were studied morphologically and counted at 1, 2, 4, and 7 days. RESULTS: Tfr-rRA (10-10,000 ng/ml) killed proliferating human retinal pigment epithelial cells and rabbit dermal fibroblasts in a dose-dependent manner (p < or = 0.01) up to a maximum of 86% and 93%, respectively. In contrast, Tfr-rRA had minimal effect on density-arrested human retinal pigment epithelial cells and rabbit dermal fibroblasts. The cytotoxicity of Tfr-rRA was inhibited by the addition of human transferrin (65.7 mg/l), an effect that was partially overcome by longer treatment with Tfr-rRA. Monensin (0.01 microM) increased the cytotoxicity of Tfr-rRA by 4.8-fold over Tfr-rRA alone, shortened the onset of cell kill with Tfr-rRA from 48 to 24 hours (P = 0.04), and partially reversed the neutralizing effect of human transferrin. CONCLUSIONS: The results indicate that Tfr-rRA effectively inhibited the proliferation of human retinal pigment epithelial cells and rabbit dermal fibroblasts in vitro. The inhibitory effect could be modified by the addition of human transferrin or monensin. Thus, this ricin A chain conjugate may interrupt the proliferation of cells necessary in the pathogenesis of proliferative vitreoretinopathy.

Animals↗
PubMed1993

Expression of three forms of melanoma growth stimulating activity (MGSA)/gro in human retinal pigment epithelial cells.

PURPOSE: To characterize mRNA expression and protein production of the cytokine MGSA/gro in human retinal pigment epithelial (RPE) cells and to determine whether expression of MGSA/gro is modulated by serum and the cytokines interleukin 1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), or transforming growth factor beta (TGF beta) mediators implicated in proliferative vitreoretinopathy (PVR). METHODS: Reverse-transcription polymerase chain reaction was used to determine the steady-state mRNA expression of three forms of MGSA/gro, alpha, beta, and gamma, by cultured human RPE cells in the presence or absence of recombinant IL-1 beta, TNF alpha, or TGF beta, or when serum-starved cells were re-fed with medium containing serum. Immunocytochemistry was used to characterize RPE cell-associated MGSA/gro protein, and immunoprecipitation of MGSA/gro from cell-conditioned medium was used to demonstrate MGSA/gro secretion. RESULTS: MGSA/gro mRNA was expressed minimally under basal conditions. Expression for all three forms of MGSA/gro mRNA was induced in a dose- and time-dependent manner after exposure to IL-1 beta, to a lesser extent after exposure to TNF alpha, but not after exposure to TGF beta. Serum induced MGSA/gro alpha and gamma transcripts, but not beta transcripts. Cell-associated MGSA/gro was identified on RPE cells grown in the absence of cytokines, but MGSA/gro was not secreted under these conditions. Exposure to IL-1 beta did not consistently cause increased cell-associated MGSA/gro; however, IL-1 beta induced secretion of MGSA/gro in a time-dependent manner. CONCLUSION: MGSA/gro is produced by human RPE in response to mediators implicated in PVR. Because MGSA/gro is a pleiotropic modulator of cell proliferation and inflammation, it may contribute to the intraocular wound healing response that characterizes PVR.

Blood Proteins↗
PubMed1993

Minoxidil inhibits ocular cell proliferation and lysyl hydroxylase activity.

PURPOSE: To examine the antiproliferative and lysyl hydroxylase-suppressing effects of minoxidil on cultured proliferating and density-arrested human retinal pigment epithelial cells (hRPE) and Tenon's capsule fibroblasts (hTCF). METHODS: Proliferating and density-arrested hRPE and hTCF, exposed to minoxidil (0.1-5 mM) for 15 min to 7 days, were examined by proliferation assays, [3H]thymidine incorporation, trypan-blue exclusion, and phase-contrast microscopy. The lysyl hydroxylase-suppressing effects were examined in confluent hRPE exposed to minoxidil (0.01-1 mM) using L-[4,5-3H]-lysine-labeled procollagen substrate and measuring the amount of tritium released as 3H2O after vacuum distillation. RESULTS: Minoxidil (0.1-5 mM) inhibited the proliferation of subconfluent cultures of hRPE and hTCF in a dose-dependent manner with a half-maximal effect at 1.5 and 2.5 mM, respectively. The antiproliferative effect, detectable within 24 hr, occurred with a limited exposure period and persisted even after removal of minoxidil from the culture medium. In contrast, 1-5 mM minoxidil had minimal effect on density-arrested hRPE and hTCF. However, at doses above 3 mM, although minoxidil had no effect on the number of density-arrested hRPE, morphologic and viability experiments indicated signs of cytotoxicity. Minoxidil (0.1-1 mM) caused a maximum of 71% reduction in the activity of lysyl hydroxylase, an enzyme needed for stable cross-links in collagen. CONCLUSIONS: Minoxidil may be a useful drug for the treatment of conditions such as proliferative vitreoretinopathy and bleb scarring after trabeculectomy, disorders with unwanted cell proliferation and collagen production.

Cell Count↗
PubMed1992

Progression of nonproliferative diabetic retinopathy and visual outcome after extracapsular cataract extraction and intraocular lens implantation.

Twenty-one patients with symmetric nonproliferative retinopathy who underwent extracapsular cataract extraction and intraocular lens implantation were followed up postoperatively for an average (+/- standard deviation) of 18 +/- 7 months to determine the incidence of progression of diabetic retinopathy, the final visual acuity, and factors predictive of progression of retinopathy and final visual acuity. Progression of retinopathy, defined as the development of clinically significant macular edema, an increase in intraretinal hemorrhages or hard exudate, or the development of proliferative diabetic retinopathy, was assessed in both eyes of 19 patients; in two remaining patients, dense preoperative cataract in the fellow eye precluded comparison of retinopathy progression in the operated-on eye to progression in the fellow eye. Overall, retinopathy progressed in 14 of 19 operated-on eyes (74%). Cataract extraction was highly associated with asymmetric progression of nonproliferative retinopathy; it progressed only in the operated-on eye in seven of 19 patients (37%), but in no patients did progression occur in the fellow eye alone (P = .0078). Women had a significantly increased risk of progression of retinopathy in the operated-on eye compared to men (P = .005). Visual acuity improved in 19 of 21 operated-on eyes (86%); however, only 11 eyes (52%) achieved a visual acuity of 20/50 or better and only six eyes (14%) achieved a visual acuity of 20/25 or better. In only five eyes was the final visual acuity in the operated-on eye more than two lines better than the final visual acuity in the fellow eye.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Modulation of potassium transport in cultured retinal pigment epithelium and retinal glial cells by serum and epidermal growth factor.

The ionic environment of retinal photoreceptors is partially controlled by potassium transporters on retinal glial and retinal pigment epithelial cells (RPE). In this study, serum and epidermal growth factor (EGF) were examined as modulators of potassium transport in confluent cultures of human RPE and rabbit retinal glia. EGF is a known mitogen for confluent RPE cultures and was shown here to also stimulate [3H]thymidine incorporation in cultures of retinal glia. For potassium transport studies 86Rb was used as a tracer during a 17-min incubation. For both retinal cell types the mean total 86Rb uptake in 10% serum was approximately 60% above basal, serum-free controls. For EGF, tested in several experiments in a concentration range from 1 to 100 ng/ml, maximal total uptake was 33 and 24% above controls for RPE and glia, respectively. Inhibitor studies suggested that basal and serum-stimulated uptake for both cell types occurred by the ouabain-sensitive Na-K ATPase pump and by the furosemide- or bumetanide-sensitive Na-K-Cl cotransporter. EGF-stimulated uptake appeared to be due predominantly to the cotransporter. The data suggest that serum components and EGF, which may be available to retina-derived cells under pathologic conditions, may not only stimulate proliferation but may also act as short-term modulators of potassium ion movement and thus affect physiologic processes that are sensitive to ion homeostasis.

Animals↗
PubMed1992

Modulation of macrophage colony stimulating factor in cultured human retinal pigment epithelial cells.

Steady-state mRNA expression and protein production of macrophage colony stimulating factor were measured in visually confluent monolayers of unstimulated cultured human retinal pigment epithelial cells and after cells were stimulated with recombinant cytokines. Using reverse transcription polymerase chain reaction, macrophage colony stimulating factor mRNA expression was detected in unstimulated cells obtained from each of four separate donors. In these cells, mRNA expression was accompanied by secretion of macrophage colony stimulating factor protein into cell-conditioned medium; 48 hr after cells were switched to fresh medium, the mean (+/- S.D.) quantity of macrophage colony stimulating factor, measured by enzyme-linked immunoassay, was 5.1 +/- 2.3 ng 10(-6) cells. There was a dose- and time-dependent induction of macrophage colony stimulating factor mRNA after cells were exposed to recombinant human interleukin-1 and tumor necrosis factor alpha. Maximal mRNA induction was observed in cells exposed for 4 hr to interleukin-1 beta (5 U ml-1) or for 4-8 hr to tumor necrosis factor alpha; under these conditions, macrophage colony stimulating factor mRNA was induced up to 23- and 46-fold after exposure to interleukin-1 beta and tumor necrosis factor alpha, respectively. Similarly, macrophage colony stimulating factor protein production was enhanced after cells were exposed to recombinant cytokines. Protein secretion increased 1.3-2.5-fold (P less than 0.001) after exposure to interleukin-1 beta (5 U ml-1), and 1.2-1.6-fold after exposure to tumor necrosis factor alpha (P less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1992

Expression of interleukin-1 alpha, interleukin-1 beta, and an interleukin-1 receptor antagonist in human retinal pigment epithelial cells.

mRNA expression and protein production of interleukin-1 alpha, interleukin-1 beta and intracellular and secreted forms of an interleukin-1 receptor antagonist were measured in visually confluent monolayers of unstimulated cultured human retinal pigment epithelial cells and after cells were stimulated with recombinant cytokines. Using reverse transcription polymerase chain reaction, transcripts for interleukin-1 alpha and interleukin-1 beta were not detected in unstimulated cells from any of six donors whereas mRNA expression for both interleukin-1 alpha and interleukin-1 beta was readily induced in all six cell lines after cells were stimulated with recombinant IL-1 (alpha or beta), tumor necrosis factor alpha, or lipopolysaccharide. The combination of cycloheximide and recombinant interleukin-1 caused a 14-fold enhancement of interleukin-1 alpha and interleukin-1 beta mRNA expression above that observed after cells were stimulated with interleukin-1 alone. After stimulation by interleukin-1, cells produced intracellular interleukin-1 alpha protein, but did not secrete it into medium. In contrast, interleukin-1 beta protein was not detected in cell lysates or conditioned-medium after stimulation with interleukin-1. An intracellular interleukin-1 receptor antagonist was expressed constitutively by human retinal pigment epithelial cells; mRNA transcripts were enhanced in a dose and time dependent manner after cells were exposed to recombinant interleukin-1 or tumor necrosis factor alpha. In contrast, mRNA for a secreted form of the interleukin-1 receptor antagonist was not detected under basal conditions or after cells were stimulated by recombinant cytokines. Interleukin-1 receptor antagonist protein was found primarily in cell lysates; little interleukin-1 receptor antagonist protein was secreted by the cells. The presence of cell-associated interleukin-1 receptor antagonist was confirmed by immunocytochemistry. Levels of cell-associated IL-1 receptor antagonist protein were not significantly influenced by recombinant interleukin-1 or tumor necrosis factor alpha. Endogenous expression of interleukin-1 receptor antagonist may attenuate the effect of exogenous or endogenous interleukin-1, thus providing the RPE cell a means of maintaining interleukin-1 homeostasis in ocular inflammatory disease.

Cells, Cultured↗
PubMed1992

Inhibition of human corneal epithelium with immunotoxin 454A12-rRA.

We examined the effects of the immunotoxin 454A12-rRa on proliferating and confluent human corneal epithelium (HCE) in vitro. Proliferating HCE was sensitive to 454A12-rRA in a dose-dependent fashion. At immunotoxin concentrations of 1,000 ng/ml for 7 days we observed an 86% reduction in cell counts. Confluent HCE was not sensitive to 454A12-rRA at equivalent concentrations of immunotoxin. These data confirm previous observations regarding selective sensitivity of proliferating ocular tissue to immunotoxin, but suggest that HCE is less sensitive to 454A12-rRA than other ocular cell types.

Animals↗
PubMed1991

cDNA cloning of an intracellular form of the human interleukin 1 receptor antagonist associated with epithelium.

A cDNA encoding a receptor antagonist of interleukin 1 (IL-1ra), secreted from human monocytes, has recently been isolated and sequenced [Eisenberg, S. P., Evans, R. J., Arend, W. P., Verderber, E., Brewer, M. T., Hannum, C. H. & Thompson, R. C. (1990) Nature (London) 343, 341-346]. We have identified another version of this IL-1ra, which is predominantly expressed in epithelial cells. This IL-1ra lacks a leader sequence and, thus, is probably intracellular. Both proteins are derived from the same gene through use of an alternative transcriptional start site and internal splice-acceptor site. Expression of intracellular IL-1ra cDNA in COS cells demonstrated that the intracellular product specifically inhibited exogenous interleukin 1-dependent responses. Keratinocytes were shown to contain significant amounts of nonsecreted IL-1ra protein. Constitutive expression of the intracellular IL-1ra may be an intracellular defensive mechanism in exposed epithelial cells and/or may serve to regulate autocrine interleukin 1-mediated pathways of differentiation.

Amino Acid Sequence↗
PubMed1991

The effect of culture density and proliferation rate on the expression of ouabain-sensitive Na/K ATPase pumps in cultured human retinal pigment epithelium.

The number and activity of ouabain-sensitive Na/K ATPase pumps expressed by many cell types in vitro, including human retinal pigment epithelial cells (RPE), have been shown to decline with increasing culture density. Cell proliferation also declined as cultures became dense so it was unclear if pump number was modulated by cell proliferation or culture confluency. By exposing RPE cultures to various feeding regimens, using culture medium containing or lacking serum, it was possible to produce RPE cultures with a range of culture densities and growth rates. These were analyzed for proliferative activity by quantifying [3H]thymidine incorporation and for Na/K ATPase pump number by measuring specific [3H]ouabain binding. The results suggest that pump number is modulated by culture density and, further, that the density-dependent regulation of pump number requires serum. Although density-dependent modulation of culture growth is also serum requiring, cell proliferation and pump number did not appear to be related; cultures of similar density which differed significantly in growth rate had similar numbers of pumps. The view that elevated numbers of pumps were not necessarily found in proliferating cells was further supported by qualitative examination of radioautographs of cells dually labeled with [3H]thymidine and [3H]ouabain. Cycling cells which had [3H]thymidine-labeled nuclei did not have notably higher labeling with [3H]ouabain. However, [3H]ouabain labeling, as an indicator of pump site number and distribution, did vary among cells in an RPE population and also within individual cells. This latter observation suggests that unpolarized RPE cells in sparse cultures may have regionally different requirements for ionic regulation.

Autoradiography↗