Biomedical subjects
Publications and source records attributed to M M Rodrigues.
An intravitreal CO2 laser probe phototransected vitreal membranes in rabbits with short pulses of infrared energy delivered through either an optical fiber or an articulated arm. The potential use of the CO2 laser probe appears to be as an adjunct to the mechanical vitrectors.
A 38-year-old male homosexual with the new Acquired Immunodeficiency Syndrome (AIDS) had biopsy proven Kaposi's sarcoma of the right palpebral conjunctiva, extraocular mucocutaneous areas, and lymph nodes. Histologically, the palpebral tumor was characterized by atypical spindle cell proliferation and multiple slit-like vessels. Staining for Factor VIII-related antigen was positive in the cytoplasm of some tumor cells. Electron microscopy disclosed Weibel-Palade bodies in cells lining scattered slit-like vascular channels. The palpebral tumor mass was relatively nonadherent to its surrounding tissues and thus its simple excision was noteworthy; despite the prominent vascularity of the tumor, minimal bleeding was associated with its surgical resection. Any patient with AIDS should have all mucosal surfaces routinely examined for the presence of Kaposi's sarcoma lesions.
A 24-year-old woman had insulin-dependent juvenile diabetes for 15 years. She developed Sheehan's syndrome (postpartum pituitary necrosis) and diabetic nephropathy at 20 years of age. She had multiple sessions of argon laser photocoagulation for proliferative diabetic retinopathy. Histologically, loss of outer retina and pigmented epithelium occurred at the laser sites. Trypsin retinal digest preparations revealed microaneurysms and markedly decreased numbers of pericytes. The kidneys displayed nodular glomerulosclerosis (Kimmelstiel-Wilson syndrome). The anterior pituitary showed cystic degeneration and old hemorrhage.
A 42-year-old bisexual man with the acquired immunodeficiency syndrome, cryptococcal meningitis, disseminated Mycobacterium avium-intracellulare with mycobacteremia, and oropharyngeal candidiasis developed unilateral retinitis and bilateral cotton wool patches. Histopathologic examination revealed unilateral necrotizing retinochoroiditis with virions in retinal and choroidal tissues. Postmortem cultures of retina and choroid were positive for cytomegalovirus.
A glycoprotein of 25,000 daltons (G25) purified from T. cruzi extracts is recognized by serum antibodies of Chagas' disease patients. These human antibodies were isolated by affinity chromatography and were used to demonstrate that G25 antigenic determinants are i) represented at the parasite surface, and ii) are expressed in all developmental stages of the parasite's life cycle, as well as in several T. cruzi strains. This antigen-antibody system may be useful for the diagnosis of Chagas' disease because antibodies to radiolabeled G25 are found in the serum of 96.5% of 173 chagasic patients from different endemic areas, but are not found in the serum from other individuals. Taken collectively, the data suggest that antibodies to G25 define highly conserved determinants of the species T. cruzi. Moreover, its remarkable immunogenicity to infected humans offers an opportunity to investigate the role of specific immunologic responses in the pathogenicity of Chagas' disease.
A 53-year-old Japanese woman had corneal opacification due to granular dystrophy (GCD) since childhood. Clinically, unusual bilateral confluent dense granular opacities with a peripheral rim of clear cornea were observed. Her mother and daughter have a milder form of GCD, with circumscribed opacities separated by clear stroma. Light and electron microscopy of the patient's corneal button showed that the opacities involved the corneal epithelium as well as the stroma.
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A patient with macular corneal dystrophy who had a successful 6-mm corneal transplant 23 years ago underwent a second keratoplasty for marked irregular astigmatism. The excised button, which contained the original graft and a rim of host cornea, was divided into several portions. One portion was examined histologically, another portion was incubated in organ culture with radioactive precursors and the biosynthetically labeled products characterized, and a third portion was used for cell culture and karotype analysis. The results indicated that host stromacytes had not invaded the graft and that graft stromacytes had synthesized normal proteoglycans. Furthermore, although there was excessive synthesis of abnormal proteoglycan by host stromacytes and accumulation of this material in the host cornea, minor amounts of this material actually accumulated in the graft cornea, possible contributing to the astigmatism. A large transpant that would leave a minimum of host corneal tissue may be conductive to a longer-term good result in patients with macular corneal dystrophy.
Cyclosporin A has been shown to be an effective inhibitor of T cell-mediated diseases. We show here that cyclosporin A was capable of totally preventing the clinical appearance of experimental autoimmune uveitis in Lewis rats, even when administered on an every-other-day schedule (10 mg/kg) or when begun seven days after immunization (40 mg/kg). At lower doses of the drug, a modulation of the disease was seen with evidence of a more chronic, granulomatous process. A long-lasting unresponsive state to the immunizing antigen was not uniformly induced with cyclosporin A if therapy was begun seven days after S antigen immunization. Because of cyclosporin A's effective control of this experimental model that is induced by an antigen to which certain patients with uveitis demonstrate cell-mediated immune responses, cyclosporin A may be an effective mode of therapy for T cell-mediated intraocular inflammatory disease.
A 37-year-old, white woman with xeroderma pigmentosum had reduced vision for many years because of primary and secondary corneal epithelial edema and stromal haze. Corneal grafting was required, but was not successful. Numerous primary dermal tumors of various types involving the lids of both eyes had been excised surgically or treated by freezing with liquid nitrogen. Squamous cell carcinomas involving the limbal area of the globe and adjacent tissues were excised from the left eye at age 12, the right eye at age 32, and the left eye (again) at age 36. The right limbal tumor soon recurred and invaded the orbit despite radiation treatment; this required right orbital exenteration. The second left limbal tumor recurred one year later, soon after the recurrence of a left lower lid basal cell carcinoma. Left orbital exenteration was required. Corneal graft failures and recurrent ocular squamous cell carcinoma involving the eye in xeroderma pigmentosum can be difficult management problems.
A 35-year-old homosexual man with cytomegalovirus viremia developed retinitis. He also had a new syndrome consisting of a persistent T-lymphocyte deficit, pneumocystis pneumonia, recurrent Candida albicans esophagitis, skin ulcerations caused by herpes simplex virus, Type 2, disseminated Mycobacterium avium-intracellulare infection, and molluscum contagiosum. Histopathologic examination revealed bilateral necrotizing retinitis with virions in retinal, choroidal, and optic nerve tissues. Postmortem cultures of retina and vitreous were positive for cytomegalovirus.
In 22 subjects with phakic open-angle glaucoma, trabeculectomies were performed at intervals of three hours to one year after argon laser treatment (ALT). In ten patients the ALT was done with informed consent anticipating that trabeculectomy would be performed at a scheduled time (three hours to two weeks following laser therapy). In 12 other patients, trabeculectomies were required for failure of ALT (one month to one year later). Scanning and transmission electron microscopy of the specimens examined at earlier intervals after laser therapy revealed evidence of heat effects with disruption of trabecular beams, fibrinous material, and necrosis of occasional cells, including melanin-containing endothelial cells, followed by shrinkage of the collagenous components of the trabecular meshwork. The specimens excised at longer intervals after laser treatment showed partial or total occlusion of intertrabecular spaces by a cellular layer of abnormal corneal and/or trabecular endothelial cells with widened cellular interdigitations and numerous prominent filopodial processes typical of migrating cells.
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Three Q-switched ruby laser pulses were applied to the trabecular meshwork of 10 monkey eyes. Pulse energies ranging from 20 to 110 mJ were studied. The spot size ranged from 100 to 200 micrometer (in air), and the pulse durations was 28 sec. Gonioscopic examinations showed a graded response from no appreciable change at 20 mJ per pulse to marked disruption of anterior chamber angle structures at 100 mJ or more per pulse. Perfusions done within an hour of treatment showed no consistent alteration of the outflow facility. Scanning electron microscopy demonstrated the graded anterior chamber angle response. No disruption of the angle structures was seen after the 20 mJ treatment, but discrete trabecular damage occurred after treatments with 25 mJ. After pulses equal to or greater than 45 mJ the anterior chamber angle structures were markedly altered. The power density causing extensive tissue disruption was equal to or greater than 150 X 10(8) watts/cm2. In each specimen with an identifiable trabecular lesion, tissue debris and endothelial edema were found on the adjacent inner surface of the cornea. Tearing of Descemet's membrane next to the trabecular meshwork occurred with the 100 mJ pulses.
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A progressive nonedematous keratopathy developed in a 36-year-old patient after she was struck in the eye by glass fragments. Biopsy material that was examined by electron microscopy and electron beam microanalysis demonstrated the presence of intracorneal glass fragments, which could not be detected clinically. Retained intracorneal glass, generally thought to be completely inert, can be associated with a chronic keratopathy.
The sources of cellular constituents of fibrous and cellophane membranes formed in massive periretinal proliferation have been unclear. We successfully obtained cellular outgrowths from abnormal vitreous specimens collected at surgery for massive periretinal proliferation in 13 patients, using standard culture techniques. By phase-contrast and ultrastructural morphological criteria, we identified four major cellular constituents: (1) macrophages present in all specimens: (2) pigmented epithelioid cells, present in a majority of specimens; (3) glial-like cells, present in a majority of specimens; and (4) fibroblastic cells, present in all specimens but much more prominent in grossly fibrous tissues. Our findings confirm published reports of pigmented epithelioid cells and glial-like cells in fixed surgical specimens and advance our understanding of the heterogeneity of pathologic cells active in producing this serious complication of retinal reattachment surgery.
The occurrence of polymorphic punctate and filamentous opacities in the axial cornea of patients in the fourth decade of life and older represents a distinct clinical entity. The glass-like deposits are usually in the deeper layers of the cornea and are associated with normal intervening stroma. Although it is not a cause of visual dysfunction, this disorder may be confused with lattice corneal dystrophy or with the corneal deposits in some dysproteinemias. Common clinical findings were found in 14 patients, and these findings were contrasted with the findings in lattice corneal dystrophy. Family studies failed to demonstrate heritability, and lesions were found in older patients only. Histopathologic examination identified the lesions as amyloid. The findings suggest that his disorder should be classified as a corneal degeneration. "Polymorphic amyloid degeneration" is a descriptive for this condition.