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Biomedical subjects

J D Gottsch

Publications and source records attributed to J D Gottsch.

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

Neurotrophic factors, cytokines and stress increase expression of basic fibroblast growth factor in retinal pigmented epithelial cells.

Basic fibroblast growth factor (bFGF) and FGF receptors have been localized to photoreceptors and retinal pigmented epithelium (RPE), but the function of bFGF in adult retina and RPE is unknown. Exogenous bFGF has a neuroprotective effect in retina and brain and its expression is increased in some neurons in response to cytokines or stress. In this study, we investigated the effect of light, other types of stress, neurotrophic factors, and cytokines on bFGF levels in cultured human RPE. Some agents that protect photoreceptors from the damaging effects of constant light, including brainderived neurotrophic factor (BDNF), ciliary neurotrophic factor, and interleukin-1 beta, increase bFGF mRNA levels in RPE cells. Intense light and exposure to oxidizing agents also increase bFGF mRNA levels in RPE cells and cycloheximide blocks the increase. An increase in bFGF protein levels was demonstrated by ELISA in RPE cell supernatants after incubation with BDNF or exposure to intense light or oxidizing agents. These data indicate that bFGF is modulated in RPE cells by stress and by agents that provide protection from stress and support the hypothesis that bFGF functions as a survival factor in the outer retina.

Blotting, Northern↗
PubMed1997

Cloning and expression of bovine corneal antigen cDNA.

PURPOSE: A cornea-associated antigen (CO-Ag) has been found to be the target for autoantibodies in patients with Mooren's ulcer. The study goals were to isolate a full-length clone encoding CO-Ag from a bovine corneal cDNA library and to express this clone in Escherichia coli (E. coli). METHODS: A DNA fragment of CO-Ag was generated, using unique oligonucleotide primers and reverse transcription polymerase chain reaction. This fragment was used as a probe to obtain cDNA clones from a bovine corneal cDNA library. The clone with the longest cDNA insert was selected for sequence analysis. Expression of the CO-Ag protein in E. coli was induced by isopropyl beta-D-thiogalactopyranoside (IPTG). The bacterially-produced CO-Ag was partially purified by calcium (Ca2+)-dependent hydrophobic interaction chromatography. RESULTS: The cDNA insert sequence was 273 nucleotides in length for the entire mRNA coding region, 212 nucleotides in the 5' untranslated region, 83 nucleotides in the 3' untranslated region and a poly(A) tail. The DNA base sequence of this clone also contained a standard initiation codon, termination codon, and the polyadenylation signal. This cDNA predicts a protein which contains 91 amino acids with a molecular weight of 10,584 daltons. The cDNA and deduced amino acid sequence of CO-Ag are completely identical to a S-100 protein, bovine calgranulin C. The cDNA was expressed in E. coli as a fusion protein consisting of 583 N-terminal amino acids of beta-galactosidase (beta-gal), 91 amino acids of CO-Ag, and possibly a number of additional N-terminal and C-terminal residues. The bacterially produced CO-Ag was fully functional with respect to hydrophobic interaction with phenyl-Sepharose matrix for its isolation. The fusion protein was recognized by antiserum raised against bovine CO-Ag protein on Western blots. CONCLUSIONS: The isolation and analysis of a cDNA clone containing the complete coding sequence of the CO-Ag protein and the expression of the CO-Ag protein in E. coli is reported. The availability of a CO-Ag cDNA probe and larger quantities of the CO-Ag protein should aid in elucidating the possible pathogenic role of CO-Ag in Mooren's ulcer.

Amino Acid Sequence↗
PubMed1997

Cloning and sequence analysis of human and bovine corneal antigen (CO-Ag) cDNA: identification of host-parasite protein calgranulin C.

PURPOSE: The primary structure of a cornea-associated antigen (CO-Ag) has been identified and has been implicated in the pathogenesis of Mooren's ulcer. The study designs were to isolate full-length clones encoding CO-Ag from a bovine and a human corneal cDNA library so that complete sequence analyses might further define the possible role of this protein in Mooren's ulcer. METHODS: DNA fragments of bovine and human CO-Ag were generated using unique oligonucleotide primers and reverse transcription polymerase chain reaction. These fragments were used as probes to obtain cDNA clones from a bovine and a human corneal cDNA libraries. The clones with the longest cDNA inserts were selected for sequence analyses. Human cDNA fragment was digested with Stu I and Hind III and cloned into a expression vector, pPROEXHT, at the same restriction enzyme sites. The plasmid was transformed into E. coli cells. Correct cloning and the full-length sequence of human CO-Ag were determined by sequencing the insert cDNA. RESULTS: The bovine cDNA insert sequence was 273 nucleotides in length for the entire mRNA coding region, 212 nucleotides in the 5' untranslated region, 83 nucleotides in the 3' untranslated region and a poly(A) tail. The DNA base sequence of this clone also contained a standard initiation codon, termination codon, and the polyadenylation signal. This cDNA predicts a protein which contains 91 amino acids with a molecular weight of 10,584 daltons. Plasmid expression vector, pPROEXHT-CO-Ag, was constructed that direct the synthesis of human CO-Ag in E. coli as fusion protein. Human CO-Ag fusion protein was purified to 90% pure with a yield of 17.2 mg per liter of the bacterial cell lysate. The nucleotide sequence of the CO-Ag cDNA insert was completely identical to human neutrophil calgranulin C. The deduced amino acid sequence was completely identical to a Ca(2+)-binding protein isolated on the surface of filarial nematodes. CONCLUSIONS: The isolation and analysis of cDNA clones containing the complete coding sequence of bovine and human CO-Ag proteins is reported. The proteins identified by deduced amino acid sequences demonstrate 100% sequence homology with human and bovine calgranulin C. Immune recognition of calgranulin C to a filarial nematode may lead to a hyperactive autoimmune response to CO-Ag in the cornea leading to a Mooren's ulcer.

Amino Acid Sequence↗
PubMed1996

Amino acid sequence of an immunogenic corneal stromal protein.

PURPOSE: A unique cornea-associated antigen (CO-Ag) has been purified previously from stromal extracts. The protein is the target for autoantibodies in patients with Mooren's ulcer. In this study, the amino acid sequence of CO-Ag was analyzed and the structure-function properties of CO-Ag was determined. METHODS: Purified CO-Ag was subjected to N-terminal sequencing by automated Edman degradation. Binding of calcium (Ca2+) to CO-Ag was measured by a direct (45)Ca2+ -binding assay. RESULTS: The complete amino acid sequence of CO-Ag has been determined. The protein contains 70 amino acids in a single chain and lacks cysteine, tryptophan, and methionine residues. A computerized data base search of protein and nucleic acid sequences revealed strong homology to the Ca2+ -binding proteins of the S-100 family. The sequence of CO-Ag shows a high homology with calgranulin C (CaG-C) previously purified from pig granulocytes. The functional Ca2+ -binding sites of CO-Ag and CaG-C were different based on homology with known Ca2+ -binding domains and their Ca2+ -binding properties. There are three amino acid substitutions in the N-terminal Ca2+ -binding domain. Differences were functionally conserved and compatible, with minimum single-base changes in the codon structures. The greatest difference was located in the C-terminal Ca2+ -binding domain. Five consecutive amino acid changes from D63-K-K-G-A67 in CO-Ag to M63-Q-D-E-Q67 occurred in CaG-C. These differences alter the structure of CO-Ag, which no longer can bind Ca2+ ions. The existence of this nonfunctional Ca2+ -binding site was corroborated by its Ca2+ -binding properties. The number of Ca2+ -binding sites for the CO-Ag sub-unit is approximately half that of the CaG-C monomer, although these two proteins have a similar low binding constant of approximately 2 x 10(-4) M. CONCLUSIONS: These results suggest that CO-Ag is a new member of the Ca2+ -binding protein of the S-100 family heretofore undescribed in the cornea. Sequence data provide an important framework to search for sequence similarity with microbial proteins as possible substrates for molecular mimicry and for the identification of possible pathogenic epitopes in CO-Ag.

Amino Acid Sequence↗
PubMed1996

Surveillance and control of epidemic keratoconjunctivitis.

PURPOSE: The purpose of this study was to determine if the implementation of a formal set of infection-control policy and procedures (ICPPs) can reduce the number of outbreaks of epidemic keratoconjunctivitis (EKC) and the number of nosocomially infected patients in a large teaching eye institute. METHODS: A retrospective and prospective study of the incidence of EKC and the number of affected patients was performed for the years 1984 through 1991. Infection-control measures (ICPPs) were formulated in 1992 with regulations implemented for patient control and management, hand washing, instrument disinfection, medication distribution, and employee furloughs. Two levels of ICPPs were established on the basis of nonepidemic or epidemic conditions. After implementation of ICPPs, a prospective 4-year study (1992 through 1995) and statistical analysis were performed to determine whether the number of outbreaks of EKC and affected patients significantly decreased. RESULTS: The incidence of institutional EKC epidemics per year was at least one and as many as three from 1984 through 1991. After implementation of a formal set of ICPPs, no epidemics occurred in 2 of 4 years studied. The number of epidemics and affected patients was significantly less when the years before and after implementation of ICPPs were compared by chi-square analysis (P < .01 and P <. 01, respectively). CONCLUSIONS: In this first prospective study of institutional outbreaks of EKC, the implementation of ICPPs was demonstrated to be an effective means to decrease the number of EKC outbreaks and nosocomially infected patients for this particular institution. Although several reports of institutional outbreaks of EKC have described infection-control measures that eventually controlled an outbreak well under way, this study provides policies and procedures that may effectively decrease the number and size of nosocomial epidemics of adenoviral conjunctivitis in large teaching eye institutions.

Adenovirus Infections, Human↗
PubMed1995

Persisting epithelial herpes simplex keratitis while on cyclosporin-A ointment.

BACKGROUND: This is the first report of cyclosporin-A ointment (CsA) adversely affecting epithelial herpes simplex virus keratitis in a corneal graft. METHODS: The details of this case were obtained from the patient's record at The Wilmer Ophthalmological Institute. RESULTS: Ceasing CsA ointment resulted in resolution of the epithelial HSV keratitis. CONCLUSION: Immunosuppression caused by CsA ointment resulted in persisting epithelial HSV keratitis despite adequate topical treatment.

Aged↗
PubMed1995

Autoimmunity to a cornea-associated stromal antigen in patients with Mooren's ulcer.

PURPOSE: To purify and characterize a cornea-associated antigen (CO-Ag) and to determine antibody levels to CO-Ag in patients with Mooren's ulcer. METHOD: Standard ion exchange and gel filtration chromatographies were used to isolate and purify CO-Ag from crude bovine stromal extracts. The serum of a patient with Mooren's ulcer, containing a high level of antibodies directed against CO-Ag, was used to monitor isolation procedures. Using this newly purified CO-Ag, an enzyme-linked immunoabsorbent assay was used to detect the presence of antibodies to CO-Ag in the sera of other patients with Mooren's ulcer. RESULTS: CO-Ag was purified to apparent homogeneity from bovine corneal stromal extracts by a series of ion exchange chromatographies and gel filtration. Polyacrylamide gel electrophoresis showed that CO-Ag was a tetramer with a molecular weight of 30,000 d that may dissociate under denaturing conditions into a monomer of 7000 d. Strong indirect immunofluorescent staining was demonstrated of the stroma by guinea pig anti-CO-Ag antibody. A statistically significant difference in the level of specific antibodies to CO-Ag between patients with Mooren's ulcer and controls was found (P < 0.001). The antibody level was elevated in patients with Mooren's ulcer (mean antibody level, 0.58 +/- 0.13) compared with the controls (mean antibody level, 0.22 +/- 0.04). CONCLUSION: These results suggest that an autoantigen exists in the corneal stroma that reacts with serum antibodies from patients with Mooren's ulcer. The availability of a purified corneal antigen could facilitate the diagnosis and define the pathogenetic mechanisms in Mooren's ulcer.

Animals↗
PubMed1995

Pseudophakic Candida parapsilosis endophthalmitis with a consecutive keratitis.

We describe a case of Candida parapsilosis endophthalmitis with a consecutive keratitis after phacoemulsification and posterior chamber intraocular lens implantation in an otherwise healthy eye. Despite aggressive medical and surgical management during a 2-year period, multiple episodes recurred, with the development of an intracapsular plaque and an infectious nidus on the corneal endothelium 6 months after the initial presentation. After subtotal removal of the culture-positive capsule, intravitreal and topical amphotericin B, and oral fluconazole, the inflammation improved. However, the corneal endothelial plaque persisted with recurrent inflammation 2 months later, prompting debridement of the culture-positive plaque and further removal of the culture-negative capsular remnants and lens implant. The infection was quiescent for the subsequent 12-month period until recurrent intraocular inflammation developed with enlargement of the endothelial plaque. Culture of this plaque was again positive for C. parapsilosis. After debridement and intraocular and topical amphotericin B, the eye has now been quiescent for 13 months. This case demonstrates the development of a secondary keratitis in an eye affected by pseudophakic C. parapsilosis endophthalmitis, with the posterior cornea serving as a sanctuary site for the fungus despite aggressive management leading to recurrent infection 1 year after the clinical disease appeared to be quiescent.

Aged↗
PubMed1994

Risk factors for corneal graft failure and rejection in the collaborative corneal transplantation studies. Collaborative Corneal Transplantation Studies Research Group.

PURPOSE: To evaluate comprehensively the magnitude of suspected risk factors for corneal graft failure from any cause, failure from rejection, and immunologic reaction in patients at high risk for graft failure after corneal transplantation. METHODS: The records of the 457 participants in the Collaborative Corneal Transplantation Studies were reviewed. All participants had at least two quadrants of stromal vascularization and/or a history or previous graft rejection. Patients were followed for 2 to 5 years. Characteristics of the patient, study eye, donor, donor-recipient histocompatibility, and surgical procedure were examined for their association with the graft outcomes of failure from any cause, rejection failure, and immunologic reaction. Multivariate survival analysis techniques were used to estimate rates of graft outcome events and to estimate the magnitude of risk factors. RESULTS: Many apparent risk factors did not maintain their association with graft outcomes after adjustment for other risk factors. Young recipient age, the number of previous grafts, history of previous anterior segment surgery, preoperative glaucoma, quadrants of anterior synechiae, quadrants of stromal vessels, a primary diagnosis of chemical burn, and blood group ABO incompatibility were among the strongest risk factors identified for graft failure. Donor and corneal preservation characteristics had little influence on graft outcome. CONCLUSIONS: Risk of graft failure varies substantially, even within a high-risk population. The number of risk factors present should be considered by the patient and surgeon when contemplating transplantation and planning follow-up.

Adolescent↗
PubMed1994

Photosensitization-induced retinopathy in the newborn beagle.

PURPOSE: Photosensitization is a mechanism by which oxygen and light may interact to generate free radicals capable of tissue injury. It has been proposed as a possible etiologic mechanism in the development of retinopathy of prematurity. The authors report the effects of light exposure and a photosensitizer, rose bengal (RB), on the developing retina of the beagle puppy. METHODS: Seven purebred beagle puppies (2 or 7 days old) were given RB (7.5 mg/ml) intravenously (0.9 ml bolus followed by a 74 microliters/min constant infusion), and one eye was exposed to filtered light delivered by a modified slit lamp at 30 mW/cm2 for 5, 15, 25, 35, and 45 minutes. The fellow eye was not irradiated and served as an RB-only control. Three beagles were exposed to light (one eye only) for 15 to 120 minutes in the absence of RB to provide light-only and no-treatment control eyes. Animals were followed clinically by indirect ophthalmoscopy and fluorescein angiography, and eyes were processed for light microscopy. RESULTS: Clinical and/or histologic abnormalities were found in all seven eyes exposed to light in the presence of rose bengal, as follows: vitreous hemorrhage in four eyes, incomplete peripheral retinal vascularization in four eyes, fibrovascular/fibrocellular proliferation with traction on the retina in two eyes (including preretinal neovascularization in one eye), total or partial retinal detachment in two eyes, dilated peripheral vessels compatible with shunt vessels in one eye, retinal dysplasia with loss of normal architecture and formation of rosettes in five eyes. All 13 control eyes showed normal, complete retinal vascularization. CONCLUSIONS: The failure to progress to the end-stage tractional retinal detachment seen in human infants is a shortcoming of existing animal models. Photosensitization injury to the developing retina in this animal model can produce a spectrum of retinal pathology that includes extraretinal vascularization and subsequent retinal detachment.

Animals↗
PubMed1993

Light-induced deposits in Bruch's membrane of protoporphyric mice.

Photosensitization of choriocapillary endothelium with blood-borne photosensitizers, such as protoporphyrin IX, has been proposed as a mechanism for the choriocapillary sclerosis and Bruch's membrane deposits seen in age-related macular degeneration. Utilizing a mouse model of protoporphyria with approximately a 10-fold increase in protoporphyrin IX level and exposure to blue light (14 microW/cm2; bandwidth, 390 to 430 nm), a time- and light-dependent increase in choriocapillary and sub-retinal pigment epithelium basal laminar-like deposits could be demonstrated at 7 months by transmission electron microscopy. Thickening of the choriocapillary endothelial basement membrane with a homogeneous electron-dense material was first noted in protoporphyric mice exposed to blue light for 13 weeks. At 28 weeks the experimental animals exhibited a thick band of homogeneous deposits at the level of the choriocapillary basement membrane and electron-dense fibrillogranular deposits of varying sizes along the inner aspect of Bruch's membrane, with fibrils measuring up to 16 nm, with a periodicity of 13 nm. These deposits contributed to an overall thickening of Bruch's membrane with narrowing of the choriocapillaris. The morphologic appearance and localization of these deposits within Bruch's membrane of this animal model are similar to previously described deposits noted in the aging Bruch's membrane prior to the development of age-related macular degeneration.

Animals↗
PubMed1993

Treatment of experimental autoimmune dacryoadenitis with cyclosporin A.

Experimental autoimmune dacryoadenitis (EAD) was induced in SJL/J mice by a single injection of purified lacrimal gland antigen (LG-Ag) in complete Freund's adjuvant. The disease is characterized by lymphocytic infiltration of the lacrimal gland and production of lacrimal gland-specific antibodies. We examined the effects of cyclosporin A (CsA) on the development and progression of this inflammatory disease. CsA (100 mg/kg/day), given from the time of immunization for 14 days, completely blocked the development of EAD in all treated mice. Both cellular and humoral immune responses to LG-Ag were markedly reduced by the administration of CsA as evidenced by the near absence of lymphocyte proliferative response and the reduced production of circulating anti-LG-Ag antibodies. Delayed CsA treatment beginning on Day 7 after immunization totally abrogated the development of lacrimal histological lesions and lymphocyte proliferative response to LG-Ag. However, serum anti-LG-Ag titers were only marginally decreased in CsA-treated animals. Treatment with CsA was found effective even when daily injections were started 14 days after immunization with LG-Ag. CsA prevented the inflammatory cell response in 5 of 10 mice when the disease was established. The lymphocyte proliferative response to LG-Ag was moderately depressed in CsA-treated animals, but antibody titers were the same as those in the oil-treated control. These studies demonstrate that CsA has a therapeutic effect in this murine model of dacryoadenitis and suggest a critical role for T lymphocytes in the pathogenesis of EAD.

Animals↗
PubMed1993

Clinical experience with N-butyl cyanoacrylate (Nexacryl) tissue adhesive.

BACKGROUND: To investigate the indications, outcomes, and complications of N-butyl cyanoacrylate tissue adhesive for ocular clinical use. This tissue adhesive is under investigation by the Food and Drug Administration. METHODS: N-butyl cyanoacrylate was used as an investigational device on 44 patients at the authors' institution over a 2-year period. The charts of these patients were reviewed. RESULTS: The indications for glue application included corneal perforation (19 eyes), descemetoceles (9 eyes), leaking filtering blebs (6 eyes), stromal thinning (5 eyes), wound leaks (4 eyes), and exposure keratopathy (1 eye). A bandage contact lens was used over the dried tissue adhesive in 38 of the 44 eyes. Length of glue adherence ranged from 1 to 660 days (mean, 72 days). Outcome was penetrating keratoplasty (19 eyes), no further intervention (14 eyes), enucleation (4 eyes), surgical revision of a filter (2 eyes), scleral patch graft (1 eye), conjunctival transplant (1 eye), failed tarsorrhaphy (1 eye), suturing of wound (1 eye), and a lamellar graft (1 eye). Vision improved in 52% (23/44) of eyes. CONCLUSION: This tissue adhesive may soon be available to all ophthalmologists, and the authors' experience demonstrates that it is an effective method of temporary or permanent closure of an impending or frank perforation.

Adolescent↗
PubMed1993

Suture abscesses after penetrating keratoplasty.

Eighteen suture abscesses that developed after penetrating keratoplasty in 15 patients were reviewed. The time from keratoplasty to the diagnosis of an abscess ranged from 1 to 53 months with a mean of 21.5 months. In 13 of the 18 cases, the patient was taking topical steroids at the time of diagnosis. All were culture-proven bacterial ulcers, except for one case that had a positive Gram's stain, but no growth on culture. The organisms cultured were Staphylococcus epidemidis (six eyes), Streptococcus pneumoniae (five eyes), Sta. aureus (four eyes), Str. viridans (two eyes), Klebsiella oxytoca (one eye), Serratia marcescens (one eye), Moraxella sp (one eye), and Escherichia coli (one eye). The offending suture was removed in all cases, and the eyes were treated with topical fortified antibiotics (cefazolin and tobramycin). After treatment, 67% (12 of 18 eyes) had clear grafts, 17% (three of 18 eyes) were scarred, and 16% (three of 19 eyes) had failed grafts. Intensive topical steroid therapy was used when a subsequent graft rejection developed. Retained sutures following corneal transplants can result in sight-threatening infections and should be considered for removal as soon as the wound is well healed.

Abscess↗
PubMed1993

An elevated hematogenous photosensitizer in the preterm neonate.

PURPOSE: Human blood contains low levels of protoporphyrin IX (PP IX), a photoactive compound that produces reactive oxygen species when exposed to light. It has been proposed that photoactivation of PP IX and subsequent generation of potentially tissue-damaging reactive oxygen may be a mechanism of retinal injury in retinopathy of prematurity (ROP). The purpose of this study is to determine an association between blood PP IX level and infant birth-weight and gestational age. METHODS: Erythrocyte PP IX levels were measured from the umbilical cord blood of 31 neonates, both full term and preterm. Birthweights and gestational ages were recorded. RESULTS: PP IX levels in infants weighing < 1000 grams (n = 7) average 200 micrograms/dl, which is significantly higher than PP IX levels in infants weighing > 1000 grams (125 micrograms/dl, n = 24; P < 0.02). CONCLUSION: Elevated PP IX levels may place preterm neonates at increased risk for photosensitizing retinal injury.

Fetal Blood↗
PubMed1992

Mooren's ulcer and evidence of stromal graft rejection after penetrating keratoplasty.

A Mooren's ulcer developed in a 6-year-old girl after a penetrating keratoplasty for Peters' anomaly. A destructive, circumferential, and centripetal stromal ulceration recurred despite conjunctival resection, corneal gluing, topical and systemic administration of corticosteroids, and repeat graftings. Results of a systemic and a rheumatologic examination were unremarkable. Histopathologic evaluations of donor grafts consistently disclosed a lymphocytic and a plasma cell infiltrate. Indirect immunofluorescent staining using a normal donor cornea substrate was positive at the level of Bowman's membrane and stroma. The patient's lymphocytes were stimulated by a partially purified bovine corneal antigen and a positive antibody titer was found in the patient's sera to the same corneal antigen. These results suggest humoral and cell-mediated immune mechanisms can be involved in the initiation and perpetuation of a stromal rejection process after penetrating keratoplasty.

Cataract Extraction↗