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Biomedical subjects

M M Rodrigues

Publications and source records attributed to M M Rodrigues.

At least 145 records · Page 8Linked to original sources
PubMed1981

Induction of ocular inflammation by synthetic mediators.

Chemotactic mediators, N-formylmethionyl-leucyl-phenylalanine (FMLP) and the complement component C5a, were injected into the rabbit cornea, vitreous, and skin to induce a reaction resembling the "Arthus phenomenon." Injection of these mediators induced edema and granulocytic infiltration in the cornea, conjunctiva, and skin. These histologic changes resembled the inflammation produced by antigen (ovalbumin [OVA]) in specifically immunized rabbits. Keratitis began after two hours and subsided six hours after the injection. Conversely, the vitreous response started six hours after injection of FMLP and C5a and peaked between 24 and 48 hours. All the inflammatory reactions induced by FMLP, C5a, and rechallenge with antigen could be inhibited in varying degrees by subconjunctival injection of 0.1 mL of 10(-5)M dexamethasone, quinacrine, 5,8,11,14-eicosatetraynoic acid (ETYA), or indomethacin, agents that suppress different sites of chemotaxis of polymorphonuclear leukocytes. However, only the inflammation induced by FMLP could be inhibited by carbobenzoxy-phe-met, a competitive inhibitor of FMLP.

Animals↗
PubMed1981

Squamous epithelial implantation cyst of the iris.

A case of an iris implantation cyst was managed by penetrating keratoplasty and iridocyclectomy. The histology and electron microscopy of the cysts are described as well as the clinical histories and photographs of six additional cases. The potential complications of iris implantation cysts are iritis, cataracts, glaucoma, and decreased vision. Since ruptured cysts can cause an epithelial downgrowth, in toto removal was indicated in this case.

Adult↗
PubMed1981

Corneal elastosis in lattice corneal dystrophy: a clinicopathologic report.

The corneal button of a patient with lattice corneal dystrophy and the clinical features of elastotic degeneration was subjected to histochemical and electron microscopic examination. The elastotic material possesses distinct clinical and histological characteristics, in particular its ability to autofluorescence. This material stained positive with Verhoeff-van Gieson (elastic stain), negative to alizarin red (calcium stain), and was insensitive to elastase digestion. The characteristic electron microscopic picture of elastotic tissue and amyloid was also found. The clinical implications of elastotic degeneration are discussed.

Cornea↗
PubMed1981

Tamoxifen retinopathy. A clinicopathologic report.

A 57-year-old woman with metastatic breast carcinoma treated by surgery and high-dosage tamoxifen chemotherapy developed tamoxifen retinopathy characterized by white superficial refractile retinal lesions primarily in the paramacular area. At postmortem examination, the retinal lesions seen clinically were identified as being 3 to 10 microns in diameter in the macular area, and 30 to 35 microns in diameter in the paramacular area. The lesions were confined to the nerve fiber layer and inner plexiform layer and stained positive with stains for glycosaminoglycans. Electron microscopic examination revealed that the smaller lesions were intracellular and the larger lesions extracellular. The lesions were composed of randomly oriented branching electron dense 6-nm filaments accompanied by occasional electron dense coated vesicles measuring 60 to 70 nn in diameter. The lesions appeared to be occurring in axons and seemed to represent products of axonal degeneration.

Autopsy↗
PubMed1981

Cyclosporin a. Inhibition of experimental autoimmune uveitis in Lewis rats.

Cyclosporin A (CS-A), a selective inhibitor of T lymphocytes, is reported here to prevent S antigen (S-Ag) induced uveitis in Lewis rats. The S-Ag, found in all mammalian retinas, is uveitogenic under experimental conditions and patients with certain uveitic entities demonstrate cell mediated responses to this antigen. Daily treatment with CS-A (10 mg/kg) begun on the same day as S-Ag immunization totally inhibited the development of the uveitis in this experimental autoimmune model. Moreover a greater CS-A dose (40 mg/kg) efficiently prevented the disease process when therapy was started 7 d after S-Ag immunization. Anti-S-Ag antibody titers were observed to be similar in rats either protected or not protected with CS-A. Our data support strongly the need for T cell participation in this disease model. Since ocular inflammatory disease is an important cause of visual impairment, the data further suggest that CS-A may be useful in the treatment of patients with intractable uveitis.

Animals↗
PubMed1981

Further characterization of epiretinal membranes in human massive periretinal proliferation.

Periretinal membranes obtained at vitrectomy from three patients with massive periretinal proliferation were examined by immunofluorescence and electron microscopy. Immunofluorescent staining on fresh frozen sections showed positive stain with glial fibrillary acidic protein and a weaker stain with antibodies to actin, PBM-1 and laminin. Staining was negative for antibodies to actin, PBM-1 and laminin. Staining was negative for antibodies of collagen types I, III and IV. Electron microscopy revealed abundant glial cells arranged in a tubulo-acinar configuration with junctional complexes, apical microvillous processes and 9-10 nm cytoplasmic filaments.

Antibodies↗
PubMed1981

Effect of selected intravitreal drugs after severe penetrating injury in rabbits.

The rabbit model of severe double penetrating posterior injury associated with a large vitreous hemorrhage was used to test the efficacy of selected chemotherapeutic agents in preventing vitreal membranes. Intravitreal injection of cytosine arabinoside, doxorubicin, or dexamethasone did not alter the frequency or severity of the resultant vitreal membranes.

Animals↗
PubMed1981

Langerhans cells in the normal conjunctiva and peripheral cornea of selected species.

The distribution of Langerhans cells (LCs) in human corneal and conjunctival epithelial sheets was investigated by histochemical, immunofluorescence, and immuno-electron microscopic methods. The LCs stained positive with ATPase and with antibodies to HLA-DR antigen and were negative to DOPA-oxidase. Human conjunctiva showed 250 to 300 LCs/mm2 compared to 15 to 20/mm2 in the peripheral third of the corneal epithelium, approximately similar of LCs were present in Lewis rat, fewer cells in guinea pigs and mice, and no detectable cells in the chick.

Animals↗
PubMed1981

Detection of specific collagen types in normal and keratoconus corneas.

Keratoconus is a corneal disease of unknown cause that involves a progressive thinning and scarring of the corneal connective tissue. We examined normal human and keratoconus corneas, including one healed penetrating keratoplasty specimen. Organ cell cultures of normal and keratoconus corneal specimens were labeled with radioactive proline and analyzed by CM-cellulose chromatography and slab gel electrophoresis to determine collagen biosynthesis. Collagen types I and III were synthesized in similar amounts by normal and keratoconus stromacytes in culture. Specifically purified antibodies were used to determine the distribution of collagen types in tissue sections by immunofluorescence. The distribution of collagen types I, III, and IV in keratoconus was also similar to that in normal corneas, except that scarred regions in keratoconus and at the host-graft juncture were largely type III. Immunofluorescent reaction of the anti-type IV collagen antibodies with Bowman's layer, in particular, and Descemet's membrane in keratoconus specimens indicated extensive destruction. Basement membrane destruction may play an important role in this disease.

Adult↗
PubMed1980

Unusual superficial stromal corneal deposits in IgG kappa monoclonal gammopathy.

Unusual corneal stromal deposits at the level of Browman's membrane and superficial stroma were associated with severe photophobia and tearing as the initial signs of an IgG kappa monoclonal gammopathy. A corneal biopsy specimen showed superficial stroma areas that stained red with Masson trichrome stain. These deposits were positive for IgG and kappa chains. Histopathologic examination revealed focal disruption in Bowman's membrane with extension into the epithelium. Electron microscopy of the deposits disclosed parallel linear profiles compatible with immunoglobulin.

Adult↗
PubMed1980

Glaucoma due to endothelialization of the anterior chamber angle. A comparison of posterior polymorphous dystrophy of the cornea and Chandler's syndrome.

Posteroir polymorphous dystrophy (PPMD) and Chandler's syndrome are separate ocular diseases with certain clinical features in common. Both may cause endothelial dystrophy, corneal edema, iridocorneal adhesions, and glaucoma. Differences between the two disorders include the morphology of the endothelial dystrophy, hereditary transmission, laterality, and rate of progression. Histopathologic examination of trabeculectomy and iridectomy specimens from two patients with Pmd and one patient with Chandler's syndrome disclosed a common basic pathologic process--endothelialization of the anterior chamber angle. Ectopic corneal endothelium and abnormal Descemet's membrane extended across the trabecular meshwork and onto the anterior surface of the iris. The appearance of the endothelial cells, however, was strikingly different in the two conditions. The endothelial cells in PPMD had ultrastructural characteristics of epithelial cells. Those in Chandler's syndrome were degenerated but retained ultrastructural features of endothelial cells.

Anterior Chamber↗
PubMed1980

Ultrastructure and successful keratoplasty of sclerocornea in Mietens' syndrome.

A 5-year-old boy with Mietens' syndrome had bilateral microsclerocornea, hypoplastic nose, bilaterally absent radii, elbow flexion contractures, absent left fibula, growth retardation, and normal intelligence. Both corneas measured 9.25 mm in diameter and showed diffuse anterior stromal opacification with focal nebular densities and extensive superficial vascularization. Penetrating keratoplasty in one eye remained clear and compact two years postoperatively and visual acuity improved. Histopathologically, vascularized collagenous tissue occupied the anterior one fourth of the corneal stroma and contained bundles of collagen fibrils 75 to 90 nm in diameter. Descemet's membrane showed abnormal anterior lamination.

Abnormalities, Multiple↗
PubMed1980

Corneal epithelial lesions in keratosis follicularis (Darier's disease).

The prevalence of eyelid keratotic plaques and unique corneal changes associated with Darier'sdisease, peripheral epithelial nebular opacities associated with irregular surface of the central corneal epithelium, are described. These corneal lesions occurred in 16 of 21 patients. The corneal lesions were asymptomatic, stable, and did not respond to oral retinoid therapy. Histopathology of the peripheral corneal opacities showed epithelial cell edema especially in the basal layer, and decreased desmosomes.

Adolescent↗
PubMed1980

Collagen, factor VIII antigen, and immunoglobulins in the human aqueous drainage channels.

Twenty-five trabeculectomy specimens from patients with primary open angle glaucoma and chronic angle closure glaucoma, and 11 age-matched controls were examined by immunofluorescence and immunoperoxidase techniques to determine the types of collagen, immunoglobulins, and the presence of factor VIII-related antigen in the human aqueous drainage channels. In the glaucoma cases and in controls, we demonstrated that the electron dense basement membrane-like material in the peripheral portion of the trabecular beams and in the juxtacanalicular meshwork, consists at least in part, of type IV collagen, a noncollagenous protein ("laminin") and fibronectin. Factor VIII-related antigen was demonstrated in conjunctival vessels of the control eyes. Schlemm's canal and the trabecular endothelial cells did not stain for factor VIII-related/antigen in any of the specimens examined. No deposits of IgA, IgM, IgG, and the C3 component of complement were detected in the aqueous drainage channels.

Aged↗
PubMed1980

Macular corneal dystrophy: failure to synthesize a mature keratan sulfate proteoglycan.

Corneal specimens obtained during surgery from patients with macular corneal dystrophy and obtained at autopsy from control eyes were incubated in a medium containing radioactive precursors of glycoproteins and proteoglycans. Biosynthetically radiolabeled material was extracted and characterized by using molecular sieve chromatography and specific enzymes. Cells in control corneas synthesized both a chondroitin sulfate proteoglycan and a keratan sulfate proteoglycan similar to those present in monkey and bovine corneas. Cells in macular corneas synthesized a normal chondroitin sulfate proteoglycan but did not synthesize either keratan sulfate or a mature keratan sulfate proteoglycan. Instead, macular corneas synthesized a glycoprotein with unusually large oligosaccharide side chains. This glycoprotein was not detected in normal corneas and is slightly smaller than normal keratan sulfate proteoglycan. The failure to synthesize a mature keratan sulfate proteoglycan may produce corneal opacity and result in blindness. Because of evidence indicating that the corneal keratan sulfate proteoglycan is normally synthesized through a glycoprotein intermediate [Hart, G. W. & Lennarz, W. (1978) J. Biol. Chem. 253-5795-5801], macular corneal dystrophy may be a defect in glycoprotein processing.

Chondroitin Sulfate Proteoglycans↗
PubMed1980

Epithelialization of the corneal endothelium in posterior polymorphous dystrophy.

The unusual cell type present on the posterior corneal surface of posterior polymorphous dystrophy patients has been characterized. In addition to microvilli and desmosomes, these cells contain abundant 10 nm filaments which by immunofluorescent staining were shown to consist of keratin proteins, a marker for epithelial cells.

Cornea↗