Biomedical subjects

M M Rodrigues

Publications and source records attributed to M M Rodrigues.

At least 73 records · Page 4Linked to original sources

PubMed1988

Novel 17-kilodalton Leishmania antigen revealed by immunochemical studies of a purified glycoprotein fraction recognized by murine T lymphocytes.

Recently, a glycoprotein fraction, designated gp10/20, purified from Leishmania mexicana amazonensis was shown to induce a cellular immune response mediated by murine L3T4+ T lymphocytes. This fact led us to pursue further the characterization of this fraction. The present study demonstrated that gp10/20 is a degradation product of a 17-kilodalton antigen present in promastigotes and amastigotes of L. mexicana amazonensis. This antigen was easily detected in promastigotes of L. mexicana mexicana, L. donovani, L. chagasi, L. major, and L. tropica. However, culture forms of L. braziliensis complex expressed either low amounts of the 17-kilodalton antigen or an antigenically unrelated antigen. The recognition of gp10/20 by several serum samples of patients with kala-azar was also shown.

Animals↗

PubMed1988

Multiple dosing of prostaglandin F2 alpha or epinephrine on cynomolgus monkey eyes. III. Histopathology.

Prostaglandins (PGs), or their derivatives, are potent ocular hypotensive agents which may prove useful in glaucoma therapy. PGF2 alpha (250 micrograms in 50 microliter saline) or epinephrine 2% solution (50 microliter) was topically applied twice daily for 2 weeks to one eye of six cynomolgus monkeys for each agent. Contralateral control eyes received their respective vehicles. By light microscopy, there was no evidence of inflammation, corneal changes, retinal pathology (including cystoid macular edema), or other adverse effects. Likewise, by electron microscopy of the peripheral cornea, anterior chamber angle, iris base and ciliary body, no differences were noted between treated and control eyes. Therefore, multiple dosing with PGF2 alpha in subhuman primate eyes did not result in notable histopathological changes that would contraindicate a clinical trial in glaucoma patients.

Animals↗

PubMed1988

Recent advances in corneal stromal dystrophies.

Newer biochemical, immunohistochemical, and cell culture techniques have been used to investigate metabolic abnormalities in corneal stromal dystrophies. Organ cultures of macular corneal dystrophy (MCD) have shown a defect in the synthesis of keratan sulphate proteoglycan. Alterations in corneal stromal glycoconjugates have also been detected using biotinylated lectins. An absence of normal keratan sulphate proteoglycan has been shown in the blood of patients with MCD. Granular corneal dystrophy (GCD) is associated with increased phospholipid, as shown by biochemical analysis and staining with Luxol-fast blue. Immunohistochemical stains revealed reactivity with antibodies against microfibrillar protein at the edges of the deposits. Clinically, recently described early features of lattice corneal dystrophy (LCD) include discrete ovoid subepithelial opacities, a diffuse central anterior stromal haze, and anterior stromal dots and filamentary lines. Early clinical recognition of these corneal genetic disorders, with appropriate studies to define their nature and possible pathogenetic mechanisms, are important in expanding our knowledge of this disease spectrum.

Amyloid↗

PubMed1987

Unesterified cholesterol in Schnyder's corneal crystalline dystrophy.

We examined a 51-year-old woman who had bilateral corneal crystalline deposits unassociated with xanthelasma or systemic involvement. Her son had similar corneal lesions. Plasma cholesterol and apolipoprotein A-I and B levels were normal in both patients. Histopathologic examination of the corneal button in the mother obtained at the time of keratoplasty disclosed lipid deposits that stained with oil red O as well as with filipin, a fluorescent probe that specifically detects unesterified cholesterol. Electron microscopy showed abnormal accumulation of lipid and cholesterol in the central and paracentral basal epithelium, Bowman's layer, and superficial stroma.

Cholesterol↗

PubMed1987

An immunohistopathologic study of trilateral retinoblastoma.

We examined retinal and midline pineal tumors from four patients with trilateral retinoblastoma who had antibodies against neural-associated antigens including neuron-specific enolase, photoreceptor cell proteins (S-antigen and rhodopsin), and glial fibrillary acidic protein. Expression of neuron-specific enolase was observed in all four patients. S-antigen immunoreactivity was present in three of four ocular tumors and two of four pineal tumors examined, whereas results of labeling with rhodopsin and glial fibrillary acidic protein were negative in each of the ocular and pineal tumors.

Brain Neoplasms↗

PubMed1987

Retinoblastoma. Immunohistochemistry and cell differentiation.

Tumor from eight enucleated eyes was analyzed by immunohistochemistry, using a panel of specific antibodies including interphotoreceptor retinoid-binding protein (IRBP), S-antigen (S-Ag), opsin, neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), laminin, and vimentin. In addition, immunoelectron microscopy and enzyme-linked immunosorbent assay (ELISA) for IRBP were performed. Immunohistochemical staining disclosed the most pronounced labeling of tumor cells with NSE and IRBP antibodies. A correlation was found between the degree of tumor differentiation and amount of IRBP, a protein specifically synthesized by photoreceptor cells. Moderate labeling of the better differentiated tumors was also observed with antibodies against S-Ag and focal labeling in a few tumors with opsin antibodies. Anti-GFAP labeling was limited to a smaller number of reactive glial cells and perivascular glial cells. These data indicate the essential neuronal nature of retinoblastoma tumor cells in situ as well as at least partial photoreceptor-like features, as shown by the presence of recognized photoreceptor cell markers (IRBP, S-Ag, opsin). Tissue culture studies using the human Y-79 retinoblastoma cell line also demonstrate that the tumor cells are primitive multipotential retinoblasts capable of at least partial differentiation along neuronal, glial, or pigment epithelial cell lines.

Antibodies, Anti-Idiotypic↗

PubMed1987

Retinitis pigmentosa with segmental massive retinal gliosis. An immunohistochemical, biochemical, and ultrastructural study.

A morphologic, immunohistologic, and biochemical study was made on the eyes of a 79-year-old woman with clinically documented retinitis pigmentosa (RP). The methods included light and electron microscopy, immunohistologic staining, and biochemical analysis of interphotoreceptor retinoid-binding protein (IRBP) and cyclic nucleotides. Results from a histopathologic examination showed marked equatorial pigmentary retinal degeneration as well as peripheral chorioretinal atrophy corresponding to areas of paving stone chorioretinal changes. An unusual finding was a localized equatorial nodule in the right eye that stained with anti-glial fibrillary acidic protein (GFAP) antibodies, and showed lipid infiltrates in its margin and base. The equatorial retina showed marked gliosis of the outer layers. Photoreceptor cells were present only in the posterior retina, macula, and focally, in the far periphery. These areas corresponded to detectable IRBP assessed by immunohistochemical staining and biochemical analysis using the enzyme-linked immunosorbent assay (ELISA). Cyclic nucleotides were reduced in the peripheral retina, in areas of photoreceptor cell loss.

Aged↗

PubMed1987

Prealbumin. A major constituent of vitreous amyloid.

Vitreous amyloid may be the presenting clinical manifestation of types 1 and 2 familial amyloidotic polyneuropathy or complicate the course of these syndromes. Recent studies have shown that the major subunit protein composing amyloid fibrils in these conditions is a variant or abnormal prealbumin molecule and that affected individuals have low levels of this protein in their blood. The authors studied material obtained at vitrectomy from two cases of vitreous amyloid. One of these was nonfamilial and the other familial. Two-dimensional gels of solubilized protein from pelleted and washed vitreous amyloid in both cases were found to consist of material with the molecular weight and isofocusing coordinates of prealbumin monomer. Reactivity of fibrils with a monospecific antiserum to prealbumin was confirmed by colloidal gold immunoelectron microscopy. Non-familial as well as familial vitreous amyloid may in fact be systemic forms of amyloidosis due to deposition of prealbumin which can be characterized by biochemical or immunohistologic studies of material obtained at vitrectomy.

Amyloid↗

PubMed1987

Actin filament localization in developing and pathologic human corneas.

Actin is associated with motility, cell morphology, and cell-substrate adhesion. The molecular probe NBD phallacidin, which reacts with filamentous actin, was used to study the distribution of actin filaments in the corneal and conjunctival epithelium, stroma, and endothelium. Frozen sections of human fetal eyes from 8 weeks to 40 weeks of gestation were reacted with NBD phallacidin. Pathologic tissues included keratoplasty specimens from patients with hereditary posterior polymorphous corneal dystrophy (PPMD) and surgically excised tissues removed for treatment of epithelial down-growth. Normal human cornea was used as a control. Immunofluorescent staining disclosed actin filament distribution in corneal epithelium as early as 9-10 weeks of gestation. Staining increased with maturation until term. Adult human corneal epithelium showed more pronounced staining of the surface layers. Stromal staining was more extensive in earlier stages of gestation and decreased in later stages of gestation, after 20-21 weeks. In pathologic corneas with posterior polymorphous dystrophy, there was localization of actin, as well as keratin, in the abnormal epithelial-like layers lining the posterior cornea. In epithelial downgrowth, actin and keratin were demonstrated in multilayered squamous epithelium on the anterior iris surface. Actin appears to be involved in migration of corneal epithelial and endothelial cells.

Actin Cytoskeleton↗

PubMed1987

The cellular immune response to a purified antigen from Leishmania mexicana subsp. amazonensis enhances the size of the leishmanial lesion on susceptible mice.

Immunization of BALB/c mice with gp10/20, a glycoconjugate purified from Leishmania mexicana subsp. amazonensis, induced a delayed-type hypersensitivity response to the antigen, and a significant increase was elicited in the size of the lesion induced by a subcutaneous infection with this parasite. The increase in the lesion size was observed when mice were immunized by the subcutaneous and the intraperitoneal routes. The subcutaneous immunization with gp10/20 was unable to reverse the prophylactic effect of an intravenous injection of irradiated promastigotes. An L3T4+ T-cell line specific for gp10/20 was able to transfer this lesion-enhancing effect and specific delayed-type hypersensitivity reactivity to normal syngeneic recipients. The same T-cell line was a good producer of a hematopoietic growth factor, granulocyte-macrophage colony-stimulating factor.

Animals↗

PubMed1987

Lectin binding in retinoblastoma.

Lectins were used as cytochemical probes to examine the relationship between normal retina and retinoblastoma. Cases of retinoblastoma in which there were either Flexner-Wintersteiner rosettes or fleurettes accompanied by nontumorous retina were studied with ten biotinylated lectins. Pineal and ocular tumors from cases of trilateral retinoblastoma were also studied. Con-A, LCA, PNA, WGA and RCA-I labeled tissue of each type to varying degrees, while BS-I, DBA, SBA, S-WGA and UEA-I bound neither tumor nor retina. The high degree of binding homology suggests biochemical as well as structural similarities between these tissues.

Eye Neoplasms↗

PubMed1987

Characterization of avascular corneal wound healing fibroblasts. New insights into the myofibroblast.

The characteristics and derivation of corneal wound healing fibroblasts (myofibroblasts) were evaluated by studying the temporal changes in the cellular actin distribution of corneal fibrocytes following full thickness 3-mm diameter central corneal wounds in the rabbit. Under certain conditions these wounds heal without neovascularization, allowing for the detailed analysis of invading fibroblasts with minimal contamination by other cell types. The authors employed transmission electron microscopy to localize microfilaments, fluorescent microscopy using NBD-phallacidin, a mushroom toxin which binds specifically to f-actin and oligomeres of g-actin, to localize actin filaments, and isoelectric focusing gels to characterize actin isotypes. During the early stages of wound healing (1-7 days) there is a gradual change in the corneal fibrocytes adjacent to the wound margin characterized by the development of extensive rough endoplasmic reticulum, microtubules, a prominent Golgi apparatus, and a cortical microfilament network. This is in contrast to the normal fibrocyte, which, for the most part, lacks these structures. The development of microfilaments correlated with increased NBD-phallacidin fluorescence of fibrocytes adjacent to the wound as compared with fibrocytes farther removed from the site of injury. Fibroblasts appearing within the wound from 7 days to 2 months after injury had ultrastructural characteristics similar to those of myofibroblasts, including parallel arrays of microfilaments, stress fibers and cell-cell, cell-matrix attachments. Furthermore, these cells stained intensely with NBD-phallacidin, supporting the ultrastructural findings. At 1 month after injury, cells contained within the wound possessed predominantly nonmuscle isoactins (gamma) as seen by silver staining of isoelectric focusing gels, but little or no (smooth muscle) isoactins could be detected. Moreover, no significant differences could be detected between electrophoretic profiles obtained from wounded versus normal corneas. These morphologic and biochemical data suggest that the corneal fibrocyte may develop into a fibroblastlike cell similar to the myofibroblast, and is characterized by a marked increase in filamentous actin.

Actins↗

PubMed1986

Ultrastructure of traumatic corneal endothelial rings.

Traumatic endothelial rings were observed in the cornea obtained from a 4-year-old boy after a fatal gunshot wound to the forehead. Electron microscopy showed the injury to consist of an annular area of endothelial cell loss and disruption with adherent macrophages. Endothelial cell disruption was localized to the circular area where mechanical distortion of endothelium and Descemet's membrane caused by the impact of a projectile would be maximal.

Child, Preschool↗

PubMed1986

Clinical, electron microscopic, and immunohistochemical study of the corneal endothelium and Descemet's membrane in the iridocorneal endothelial syndrome.

Two women with the iridocorneal endothelial syndrome had unilateral corneal edema, iris stromal atrophy, and glaucoma. Each underwent penetrating keratoplasty. Transmission electron microscopy of the corneal buttons disclosed a thin, normally structured Descemet's membrane bounded posteriorly by a posterior collagenous layer that contained banded and fibrillar tissue, indicating that the disorder was acquired after childhood. Scanning electron microscopy showed some degenerated corneal endothelial cells with filopodial cytoplasmic projections, suggesting endothelial migration. Transmission electron microscopy of the endothelium showed no signs of epithelial-like alteration, such as stratification, desmosomal junctions, or increased cytoplasmic fibrils. Immunohistochemical staining of fresh-frozen sections with monoclonal antibodies to keratin showed normal staining of the epithelium and no staining of the endothelium. Occasional lymphocytes were seen within the endothelium in one case but were also observed in one case of an inherited corneal disease, posterior polymorphous dystrophy, suggesting that they might be normal "passenger" cells migrating in the endothelial monolayer.

Adult↗

PubMed1986

Immunohistochemistry and electron microscopy of cyclitic membrane. Report of a case.

An immunohistochemical study using various antibodies directed against antigens of inflammatory cells, neurons, and Müller cells, interstitial collagens (types I and III), basement membrane collagens (types IV and V), and basement membrane glycoproteins (laminin and fibronectin) was performed to characterize the components of two cyclitic membranes (in an enucleated eye and a surgical specimen) from a 15-year-old patient with an eight-year history of chronic bilateral uveitis. When specimens were obtained, no inflammation was seen clinically. Correlative light and electron microscopic examinations were also performed on one specimen. The preponderant cells in the cyclitic membrane were glial cells. The preponderant extracellular tissue within the cyclitic membrane consisted of basement membrane components. These observations suggest that cyclitic membranes could be formed mainly by the extension of proliferative glial elements from the retina, with a minor component derived from fibroblasts.

Adolescent↗

PubMed1986

Anterior clear spaces in keratoconus.

Anterior clear spaces were observed prospectively at slit-lamp examination in 26 of 69 consecutive eyes (38%) with keratoconus. Two corneal buttons with this finding were examined by light and electron microscopy and revealed breaks in Bowman's layer. Anterior clear spaces should be considered in the spectrum of clinical findings in keratoconus.

Cornea↗

PubMed1986

Retinoblastoma. A clinical, immunohistochemical, and electron microscopic case report.

A 4-year, 9-month-old boy had a history of leukocoria of the right eye for approximately six months prior to admission. The other eye was normal. There was no family history of retinoblastoma. Funduscopy disclosed a large white mass extending from the nasal pars plana to the mid-pupillary zone and the posterior pole with a near total retinal detachment in the superior temporal quadrant. A B-scan ultrasound showed an echo dense area of the anterior portion of the mass. A CT scan showed intraocular tissue densities with no evidence of optic nerve involvement or extraocular extension. Immunohistochemistry of a fresh frozen portion of tumor revealed reactivity with antibodies directed against interphotoreceptor retinoid-binding-protein (IRBP), neuron-specific enolase, glial fibrillary acidic protein, S-antigen, focal reactivity with opsin, and scattered cytoplasmic staining for cyclic GMP and cyclic GMP phosphodiesterase. Biochemical analysis of fresh frozen tissue samples confirmed the presence of IRBP. Transmission electron microscopy disclosed occasional Flexner-Wintersteiner rosettes connected by zonula adherens-like junctions. These showed inner segment-like structures containing prominent mitochondria, portions of cilia and fragments of outer segment material. These data, along with the immunocytochemistry indicates a predominant neuronal nature of the tumor cells with significant photoreceptor-like differentiation.

Child, Preschool↗

PubMed1986

Hyperglycemic acidotic coma and death in Kearns-Sayre syndrome.

This paper presents the clinical and metabolic findings in two young boys with long-standing Kearns-Sayre syndrome. Following short exposure to oral prednisone, both boys developed lethargy, increasing somnolence, polydipsia, polyphagia, and polyuria. Both presented in the emergency room with profound coma, hypotension, severe hyperglycemia, and acidosis. Nonketotic lactic acidosis was present in one and ketosis without a known serum lactate level was present in the other. Respiratory failure rapidly ensued and both patients expired in spite of efforts at resuscitation. We believe these two cases represent a newly described and catastrophic metabolic-endocrine failure in the Kearns-Sayre syndrome.

Acidosis↗