Search PubMed⌕ Search

Biomedical subjects

M Rodrigues

Publications and source records attributed to M Rodrigues.

At least 91 records · Page 5Linked to original sources
PubMed1990

IRBP: preparation and characterization of site-specific monoclonal antibodies.

Interstitial retinoid binding protein (IRBP) is a 136,000 molecular weight photoreceptor cell protein which is a highly pathogenic autoantigen for the induction of experimental autoimmune uveitis (EAU). In this study we produced a series of monoclonal antibodies (MAbs) which define different epitopes in the native molecule. These MAbs were further subdivided into three distinct groups based on a radioimmunoassay, and by ELISA assay using native IRBP and synthetic peptides corresponding to its entire amino acid sequence. Group I MAbs (MAbD7-B1 and MAbC6-B4) bound to native IRBP but not to any synthetic peptides, suggesting that their antigenic epitopes are strictly conformation dependent. Group II MAbs (MAbC7-D3 and MAbG8-H4) bound weakly to multiple peptides which shared amino acid sequence similarity located within each of four homology domains indicating that these epitopes are also conformation dependent. In group III (MAbH3-B5, MAbH7-A5, and MAbB6-D12) MAb binding was localized to a specific peptide. The MAbH3-B5 binding site was further refined to amino acid positions 361 to 367 in the native molecule. MAbH3-B5 was also useful in localizing IRBP in the mouse retina by immunohistochemical techniques. The application of these MAbs in the study of EAU and interphotoreceptor transport mechanisms is discussed.

Amino Acid Sequence↗
PubMed1990

[Electrocardiographic symptom-signal correspondence in Holter records].

STUDY OBJECTIVE: To determine the correspondence symptom-sign in 24-hours ambulatory electrocardiography records. DESIGN: Retrospective study. SETTING: Pulido Valente Hospital (Lisbon). Serviço de Cardiologia. Department of Ambulatory Electrocardiography. PATIENTS: 80 patients, who made 24-hours ambulatory electrocardiography and wrote correctly the diary. Two observators analysed the correspondence symptom-sign of 269 symptomatic moments, 10 minutes before and after the symptom by reviewing the compressed print. RESULTS: We found correspondence symptom-sign in 50% of the symptomatic moments. The correspondence change with the symptom type (increased for palpitations and dyspnea), the presence of Cardiopathy (increased for chest pain and dyspnea in patients with cardiopathy) type of cardiopathy (increased in patients with Mitral Valve Prolapse and Valvular disease) and expression used by the patient.

Adolescent↗
PubMed1990

[Rhythm profile in patients with psoriatic arthritis].

OBJECTIVE: To analyze the rhythmic profile in patients with psoriatic arthritis (PA). DESIGN: In order to evaluate the rhythmic profile of patients with PA, we have carried out ambulatory 24 hour ECG recordings in 22 patients presented consecutively to the Holter ECG laboratory. SETTING: Patients followed in a specialised rheumatology consultation, in Santa Maria Hospital. PATIENTS: We have studied 22 patients (pts), 10 male and 12 female, aged 49.8 +/- 8.4 years, presenting PA diagnosed in average 12.9 years before. A group of 36 individuals, 25 male and 11 female, aged 37 +/- 8 years and without disease, were used as control. RESULTS: All patients were in sinus rhythm with a mean heart rate of 71 +/- 6 (min - 51.5 +/- 7.0 and max - 130.3 +/- 15.0). In 8 (36.6%) there were sinus bradycardia less than 50/min and sinus tachycardia (greater than 120/min) in 15 patients (68.1%). Two patients (9%) presented supraventricular tachycardia and one had AV block. There were premature atrial systoles in 14 pts (63.6%), and ventricular arrhythmias in 9 (40.9%). In control group, there were sinus bradycardia in 16.6%, sinus tachycardia in 33.3%, premature atrial systoles in 33.3% and ventricular arrhythmias in 25% of them; in 11% there were conduction disturbances. CONCLUSIONS: a) Premature atrial systoles were the rhythm disturbance more prevalent. b) Patients with PA presented a significant higher incidence of sinus bradycardia and sinus tachycardia. c) Cardiac conduction disturbances were not frequent. d) Our results may suggest the presence of a subtle autonomic dysfunction in patients with psoriatic arthritis.

Adult↗
PubMed1989

[Anthracycline cardiotoxicity. Review of the literature and presentation of a study protocol].

Anthracyclines are drugs with widespread applications on the chemotherapy of cancer. Cardiotoxicity is an important side effect of these drugs, well known for doxorubicin, the most representative of this group of drugs. Dysrhythmias and heart failure are the most important among the toxic effects of anthracyclines and are dependent on cumulative doses reason why WHO established maximal doses for the different anthracyclines. Pathogenic hypothesis about the mechanism of the myocardial lesion induced by anthracyclines include the production of free oxygen radicals, alterations of energetic metabolism and disturbances of calcium and sodium exchange at membrane level. Early detection of the toxicity of these drugs is of utmost importance. Electrocardiography has low sensitivity and specificity. Echocardiography gives specific information about previous cardiac pathology and enables the detection of complication of the basic neoplastic disease. However, detection of early changes of left ventricular function is not accomplished so well, as it is with equilibrium radionuclide angiography. Left ventricular ejection fraction is the method of choice in the early detection of cardiotoxicity of these drugs, and its frequent evaluation enables to individualize the doses in each patient, and so, a most accurate use of the therapeutic potential of the anthracyclines. Radionuclide angiography has some important indications on the selection of patients for treatment with anthracyclines, namely: to identify patients that must be excluded from the treatment; select patients at risk of congestive heart failure; to decide the appropriate moment to stop the drugs; change the therapeutic schema, etc.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Pleomorphic adenocarcinoma of ciliary epithelium simulating an epibulbar tumor.

A 72-year-old woman had epibulbar nodules and a blind eye following trauma in childhood. Histologic examination disclosed a pleomorphic adenocarcinoma of ciliary epithelium with invasion of the epibulbar region, retina, retinal pigment epithelium, and optic nerve. The diagnosis was confirmed by histochemical stains and electron microscopy. The pigmented and nonpigmented neoplastic cells of the ciliary epithelium had a patchy basement membrane around the cell membrane and produced hyaluronic acid in the stroma.

Adenocarcinoma↗
PubMed1988

Coexpression of neuronal, glial, and major histocompatibility complex class II antigens on retinoblastoma cells.

This study identifies the presence of major histocompatibility complex class II antigens on retinoblastoma cells. In addition, the modulation of HLA-DR by interferon-gamma as well as the preferential expression of this major histocompatibility complex molecule over HLA-DQ is described. Double labeling experiments revealed that HLA-DR antigen is shared concomitantly with cells of glial and neuronal character. Investigations such as these underscore the possibility that expression of major histocompatibility complex class II antigens may function as immunological components in the host or play a role in the cellular differentiation of these tumor cells.

Antigens↗
PubMed1988

Retinal insulin receptors: localization using a polyclonal anti-insulin receptor antibody.

Although retinal insulin receptors have recently been described biochemically, the location of these receptors within the retina is unknown. The study presented here used a polyclonal anti-insulin receptor antibody (B10), immunofluorescence and immunoelectron microscopy to determine the location of insulin receptors in bovine, monkey and human retina. It was found that antibody immunofluorescence formed discrete bands localized predominantly to photoreceptor and neuronal cell bodies. In addition to the strong association with neuronal perikarya, a lower level of antibody binding was observed in photoreceptor outer segments. In human retina, some of the antibody immunofluorescence also had a pattern that suggested B10 binding to glial-like cells.

Animals↗
PubMed1988

Meibomian gland changes in the rhino (hrrhhrrh) mouse.

The rhino mouse, a single gene recessive mutation, is characterized by abnormal epidermal differentiation and maturation leading to the loss of hair at 1 month of age as well as follicular and epidermal hyperkeratoses. We evaluated the lids and corneas of nine rhino mice and their normal litter mates at various ages from 3 months to 1 year. Tissue specimens were studied by light microscopy, scanning and transmission electron microscopy as well as immunoperoxidase using a polyclonal rabbit anti-keratin antibody. At 3 months of age there was a thickening and hyperkeratinization of the palpebral epidermis which extended into and included the meibomian gland central duct. Whereas in the skin, hyperkeratinization is followed by follicular hyperkeratosis and dermal cyst formation, in the meibomian gland, ductal hyperkeratinization appeared to lead to loss of well developed acini followed by atrophy of the gland at 1 year as confirmed by immunostaining for keratin proteins. Scanning electron microscopy revealed marked plugging of the meibomian gland orifice with keratinized cells or debris in contrast to the patent orifice of the normal lid. Ocular surface changes included the presence of a whitish exudate covering the surface of the eye and increased numbers of preexfoliative corneal epithelial cells. These findings suggest that the rhino mouse may represents the first naturally occurring disorder of the meibomian gland.

Animals↗
PubMed1988

Resistance to retransformation by adenovirus but not by heterologous oncogenes in an E1-positive transformation revertant cell line may be mediated by a cellular function.

Using an indirect selection method based on drug-resistance, we have previously reported the isolation of flat revertants from adenovirus 2 transformed rat cells. Here, we demonstrate that one of these revertants has suffered a mutation in a cellular effector gene specifically required for the adenovirus-mediated expression of the transformed phenotype. Evidence for this conclusion includes the following: (1) the cells contain a 16-times amplified copy of the E1 region, thus reducing the chances of viral mutations, (2) the cells synthesized E1a and E1b proteins indistinguishable from those of the transformed parent, (3) the mutation has been stable for over 2 years, and most importantly (4) the revertant was resistant to re-transformation by E1 but not by c-myc, N-ras or polyoma middle t oncogenes.

3T3 Cells↗
PubMed1988

Development of the anchoring structures of the epithelium in rabbit and human fetal corneas.

The sequence of development of the components of the corneal adhesion complex (hemidesmosomes, basal lamina and anchoring fibrils) was studied in rabbit and human fetal corneas using electron microscopy and histochemical localization of type VII (anchoring fibril) collagen. In the rabbit, basal lamina was present at 15 days gestation, followed by hemidesmosomes (HDs) and anchoring fibrils (AFs) at 20 days gestation. Type VII collagen was first localized at 20 days. At 25 days, HDs remained low compared to the adult value. During human corneal development, basal lamina was present at 8 weeks gestation. Through 12 weeks of gestation, no HDs or AFs were discernible nor was there any type VII localization. At 13-19 weeks, HDs and cross-banded AFs were seen, and localization of type VII collagen was first noted. A palisade of filaments extending perpendicularly from the basal lamina into the underlying stroma was discernible from 13 to 27 weeks. A distinct Bowman's layer was present at 19 weeks. By 27 weeks, HDs/micron membrane were greater than or equal to the adult value, and AF penetration into the underlying stroma was also greater than or equal to the adult value. Bowman's layer had not reached adult values by term. These data indicate that after basal lamina deposition, HDs and AFs develop synchronously in both species. In humans the palisade of filaments may be the precursor of Bowman's layer, and the AF network develops within Bowman's layer.

Animals↗
PubMed1987

Immunopathology and electron microscopy of Acanthamoeba keratitis.

In order to evaluate the local cellular immune response to Acanthamoeba infection we performed immunohistochemical examinations of the corneal buttons of two patients with Acanthamoeba keratitis. We found that the corneal stroma was infiltrated with polymorphonuclear leukocytes and HLA-DR positive macrophages that appeared to be stromal keratocytes by light microscopy. Despite the presence of chronic inflammation in both patients, no stromal lymphocytes were seen in one patient and a sparse lymphocytic infiltrate was seen in the other patient. Electron microscopy confirmed the presence of macrophages, neutrophils, and Acanthamoeba organisms in these two patients.

Adult↗
PubMed1987

Isolation of variants resistant to methylglyoxal bis(guanylhydrazone) from adenovirus-transformed rat cells.

It is presumed that proteins encoded by viral oncogenes interact with proteins encoded by cellular genes to bring about the transformed phenotype. To demonstrate the existence of such cellular genes we attempted to isolate mutants with a nontransformed phenotype from an adenovirus-transformed rat cell line (F4) which contains multiple copies of the transforming E1 region. F4 cells were mutagenized with ethyl methanesulfonate and variants resistant to the anticancer drug methylglyoxal bis(guanylhydrazone) were selected. The proportion of such variants was about one in 10(6) and increased 5-fold after mutagenesis. Two variant clones (G1 and G2) were isolated and characterized: they were 5-fold more resistant to methylglyoxal bis(guanylhydrazone); they had a stable phenotype; they showed decreased drug uptake; they had a reduced ability to grow in soft agar, low serum, and nude mice; there was no detectable change in the restriction pattern of integrated viral genes or in the expression of the E1a and E1b proteins. These properties suggest that selection for methylglyoxal bis(guanylhydrazone) resistance may result in the isolation of variants with phenotypic characteristics of nontransformed cells. It was likely that these variants were altered in a cellular function required for the maintenance of the transformed phenotype.

Adenoviridae↗
PubMed1987

Lectin receptors of amyloid in corneas with lattice dystrophy.

We analyzed lectin binding patterns of amyloid glycoconjugates in patients with lattice dystrophy of the cornea. Results of paraffin and frozen sections differed in some instances. With paraffin sections, three lectins--wheat germ agglutinin (WGA), Ricinus communis agglutinin I (RCA-I), and concanavalin A (Con A)--stained the abnormal deposits. In frozen sections, the abnormal deposits were stained by five lectins--WGA, RCA-I, Con A, peanut agglutinin (PNA), and soybean agglutinin (SBA). In paraffin sections, PNA and SBA did not stain amyloid deposits. In both paraffin and frozen sections, some lectin-positive deposits corresponded to the Congo red-positive material, whereas others were present surrounding and encroaching on the Congo red-reactive material. This study demonstrates that WGA-, RCA-I-, Con A-, PNA-, and SBA-positive abnormal deposits are present in corneas with lattice dystrophy. Since lectins bind to specific sugar residues, we conclude that the abnormal deposits consist, at least in part, of glycoconjugates and that these glycoconjugates contain oligosaccharides with N-acetylglucosamine/sialic acid, mannose/glucose and terminal beta-galactose residues and chains with terminal beta-galactose-N-acetylgalactosamine disaccharides.

Adult↗
PubMed1987

Retinal insulin receptors. 1. Structural heterogeneity and functional characterization.

Neural cells of the bovine retina contain specific, high-affinity receptors for insulin. When solubilized and wheat-germ purified, these receptors exhibit a kinase activity that is capable of phosphorylating the receptor's beta-subunit (autophosphorylation) and a tyrosine-containing exogenous substrate, poly (Glu, Tyr) 4:1. Studies of the structure of retinal insulin receptors revealed the existence of two insulin receptor subpopulations. For these populations, the apparent molecular weights of the alpha-subunit were 120- and 133 kDa. This structural heterogeneity does not appear to be related to the presence of vascular contamination and stands in contrast to the brain and liver where a single alpha-subunit type was found (120 kDa for brain and 133 kDa for liver). In addition to being distinguishable by their molecular weights, the two populations of retinal insulin receptors could be distinguished in terms of (a) their solubility in Triton X-100, (b) glycosylation, and (c) recognition by anti-insulin receptor antibody. Despite these structural differences, the two populations of retinal insulin receptors appear to have similar insulin binding affinities.

Animals↗
PubMed1987

Retinal insulin receptors. 2. Characterization and insulin-induced tyrosine kinase activity in bovine retinal rod outer segments.

Bovine retinal rod outer segments (ROS) possess specific, high-affinity receptors for insulin. These receptors exhibit an insulin-stimulatable tyrosine-specific activity that is capable of phosphorylating the receptor's own beta-subunit and exogenous substrate. ROS insulin receptors exhibit heterogeneity in the apparent molecular weight of the receptor's alpha-subunit. In this regard, insulin receptors from this single cell type resemble insulin receptors obtained from whole retina, but are unlike receptors from brain and liver.

Animals↗
PubMed1987

Suprabasal expression of a 64-kilodalton keratin (no. 3) in developing human corneal epithelium.

We have previously shown that a basic 64-kilodalton (no. 3 in the catalog of Moll et al.) and an acidic 55-kilodalton (no. 12) keratin are characteristic of suprabasal cell layers in cultured rabbit corneal epithelial colonies, and therefore may be regarded as markers for an advanced stage of corneal epithelial differentiation. Moreover, using an AE5 mouse monoclonal antibody, we showed that the 64-kilodalton keratin marker is expressed suprabasally in limbal epithelium but uniformly (basal layer included) in central corneal epithelium, suggesting that corneal basal cells are in a more differentiated state than limbal basal cells. In conjunction with previous data implicating the centripetal migration of corneal epithelial cells, our data support a model of corneal epithelial maturation in which corneal epithelial stem cells are located in the limbus, the transitional zone between the cornea and conjunctiva. In the present study, we analyzed the expression of the 64-kilodalton keratin in developing human corneal epithelium by immunohistochemical staining. At 8 weeks of gestation, the presumptive corneal epithelium is composed of a single layer of cuboidal cells with an overlying periderm; neither of these cell layers is AE5 positive. At 12-13 weeks of gestation, some superficial cells of the three- to four-layered epithelium become AE5 positive, providing the earliest sign of overt corneal epithelial differentiation. At 36 weeks, although the epithelium is morphologically mature (four to six layers), AE5 produces a suprabasal staining pattern, this being in contrast to the adult epithelium which exhibits uniform staining.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1987

Immunoelectron microscopic localization of photoreceptor-specific markers in the monkey retina.

Antibodies for several molecules that function in the visual process were used to localize these molecules in primate rod and cone cells. These antibodies (monoclonal or polyclonal) were prepared against Interphotoreceptor Retinoid-binding Protein (IRBP), S-antigen (S-Ag), opsin, alpha-transducin and also against cyclic GMP (cGMP). Lowicryl-embedded tissues were labeled with secondary antibodies linked to colloidal gold. Although IRBP is predominantly an extracellular protein, the relatively small amount found intracellularly was localized mainly in rods, with little in cones. Opsin, S-Ag and cGMP were found mainly in rod cell outer segments. A polyclonal antiserum raised against transducin-alpha purified from rod outer segments predominantly labeled rod cells, but an antiserum against the carboxyterminal decapeptide of transducin-alpha labeled both rod and cone cells. Thus, most of these specialized molecules are present predominantly in rod cells, confirming major differences in components of the visual cycle in rods and cones.

Animals↗