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Biomedical subjects

M Rodrigues

Publications and source records attributed to M Rodrigues.

At least 55 records · Page 3Linked to original sources
PubMed1998

Histologic effect of diode laser sclerostomy in human cadaver eyes.

BACKGROUND AND OBJECTIVES: To study tissue effects and thresholds of efficacy in producing a full-thickness scleral fistula in human eyes obtained from cadavers. The effect of laser sclerostomies created with indocyanine green (ICG) was also evaluated. MATERIALS AND METHODS: Ab externo laser sclerostomies were produced in 12 fresh human eyes obtained from cadavers using a 200-micron diameter fiber optic connected to a diode laser system. Power settings were 500, 750, 1000, 1250, 1500, and 2000 mW with a constant duration of 100 and 200 ms. The same diode laser settings were repeated in the tissues injected with ICG. RESULTS: The laser sclerostomies were associated with heat coagulation damage adjacent to the burn margins, with disruption of stromal collagen. Tissue damage was greater at higher power and longer duration. Scleral injection of ICG prior to laser sclerostomy did not enhance laser penetration. CONCLUSION: The diode laser can create a sclerostomy in human sclera with an optimum level of 1500 mW and 100 ms. ICG did not significantly enhance the ease of penetration or reduce the association thermal damage to the sclera.

Coloring Agents↗
PubMed1998

Unusual imaging of varicose veins after radiolabeling of autologous low-density lipoproteins.

LDL-radiolabeling with various isotopes (123I, 125I, 131I, 111In, 99mTc and 67Ga, among others) has been used for imaging the arterial wall, monitoring the LDL-kinetics and in particular to assess vascular surface lining and foam cell content. From 286 patients studied with 111In-LDL scintigraphy, only 9 patients presented clinical varicosis. In 2 of these 9 patients a predominant imaging of varicose veins has been shown with scintigraphy, while in the other 7 patients no positive scintigraphic imaging could be detected. In vitro and in vivo perfusion experiments did not reveal an explanation for this unusual results. The reason for that positive LDL-uptake into varicose veins is unknown. These findings indicate that localized LDL-uptake has to be interpreted carefully in order to avoid potential false positive results.

Adult↗
PubMed1997

[Imaging of early carotid artery atherosclerotic lesions with 111In-labeled polyelonalhuman IgG (HIG)].

AIM: To assess the value of scintigraphy with 111In-HIG for diagnosis and evaluation of the stage and the clinical extent of carotid artery disease in humans a prospective clinical comparative trial of scintigraphy vs. sonography was performed. METHODS: 58 patients (38 male, 20 female; mean age 60 +/- 7 years) with hyperlipidemia and ultrasonographically detectable carotid artery lesions were studied. After i.v. injection of 18.5 MBq 111In-HIG, anterior scintigraphic images of the neck were acquired. Real time two-dimensional B-mode ultrasonography of the left and the right carotid arteries was performed. RESULTS: 111In-HIG-scintigraphy as compared to the morphological gold standard (ultrasonography) had a sensitivity of 70-73%, specificity of 33-41% and a positive predictive value of 77-82% for detecting carotid atherosclerotic lesions. There was, however, no significant correlation between scintigraphy and ultrasonography. CONCLUSION: However, the data provide evidence that the two imaging techniques are visualizing different aspects of atherogenesis. On the one hand a functional one reflecting the activity of the disease (111In-HIG) and on the other hand the morphological one resembling the extent of the disease (ultrasonography).

Aged↗
PubMed1996

Characterization of in vivo primary and secondary CD8+ T cell responses induced by recombinant influenza and vaccinia viruses.

We characterized the in vivo primary and secondary murine CD8+ T cell responses induced by immunization with influenza and vaccinia viruses, which were engineered to express the same H-2K(k)- and H-2K(d)-restricted epitopes. Our results show that the induction and magnitude of the primary CD8+ T cell response closely depends on the viral dose used for immunization, while it is not affected by the route of immunization. The induction of secondary CD8+ T cell responses appears to be highly restricted, as suggested by the lack of in vivo expansion of antigen-specific CD8+ T cells after repeated immunization with the same virus. In contrast, a 20- to 30-fold increase in the frequency of antigen-specific CD8+ T cells could be induced after combined immunization with recombinant influenza and vaccinia viruses. These findings may provide the basis for the development of new prophylactic and therapeutic strategies to prevent or control intracellular infections and certain malignancies.

Animals↗
PubMed1996

Combined study of 99mTc-HMPAO SPECT and computerized electroencephalographic topography (CET) in patients with medically refractory complex partial epilepsy.

For successful surgery for drug-resistant epilepsy the site of the seizure focus needs to be known exactly. The purpose of this study was to compare the evaluation of the regional cerebral blood flow (rCBF) (localization and degree of disturbances) by 99mTc-hexamethylpropyleneamineoxime (HMPAO) single photon emission computed tomography (SPECT) with computerized electroencephalographic topography (CET) and transmission computed X-ray tomography (CT) in partial epilepsy. The study included 20 patients with medically refractory complex partial seizures. Of the 20 patients included, 15 were studied interictally, four ictally and one in both states, interictally and ictally. 99mTc-HMPAO SPECT detected rCBF changes in 95% of the patients. Interictal studies demonstrated focal areas of hypoperfusion in 93% of the patients. Ictal studies demonstrated an area of hyperperfusion in all patients. Blood flow disturbances in deeper structures of the brain, such as basal ganglia, could be detected. The areas of abnormal 99mTc-HMPAO uptake were concordant, in localization, with CET in 85% of the patients. Abnormal data with CT scans were found in only 45% of the patients. Focal lesions were found in 20% of the patients by CT scans. 99mTc-HMPAO SPECT combined with CET may be a useful screening procedure prior to referral for invasive diagnostic procedures in future management with medically refractory complex partial seizures.

Adolescent↗
PubMed1996

Cytogenetic findings in a patient presenting simultaneously with chronic lymphocytic leukemia and acute myeloid leukemia.

A case of simultaneous presentation of B-chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) is described. CLL was documented by bone marrow and peripheral blood lymphocytosis with a typical B-CLL immunophenotype. The diagnosis of AML was supported by the presence of bone marrow and circulating blast cells positive for myeloperoxidase and myeloid-associated markers. Although the immunophenotyping and morphocytochemical studies indicated two different cell populations (mature B-CLL lymphocytes and myeloblasts), chromosome aberrations commonly associated with CLL and AML were found simultaneously in the same metaphases obtained from unstimulated 24-hour cultures of peripheral blood cells.

Aged↗
PubMed1995

Clear-cell sarcoma of tendons and aponeuroses studied by immunoscintigraphy.

Clear-cell sarcoma is a rare tumor that arises in association with tendons and aponeuroses. Although it shares with malignant melanoma several histologic and ultrastructural features, it has a clinical course different from that of conventional melanomas. A case of clear-cell sarcoma studied by immunoscintigraphy with 99mTc-labeled F(ab')2 fragments of the monoclonal antibody 225.28 S is reported.

Adenocarcinoma, Clear Cell↗
PubMed1995

PGE0 inhibits collagen and glycosaminoglycan-synthesis in the rabbit arterial wall.

The influence of 13,14-dihydro-PGE1 (PGE0), a biologically active metabolite of PGE1, on collagen and glycosaminoglycan synthesis by the rabbit arterial wall was assessed and compared with the effect of PGE1. Collagen (COL) and glycosaminoglycan (GAG) synthesis was measured using 14C proline- and 35S-incorporation respectively and both were subsequently quantified by autoradiography. PGE1 decreased GAG-synthesis by 40%, while PGE0 caused a 25% decrease. COL-synthesis after PGE1 treatment was diminished by 35%, while the biologically active metabolite caused a drop of 30%. Five and 15 micrograms/kg doses of both compounds were almost equally effective, 1 microgram was without effect. These findings indicate that PGE0 shares the inhibitory effect of PGE1 on COL and GAG biosynthesis. This metabolite has about 60 to 70% of the biological activity of its parent compound PGE1. These results suggest that part of the effects of PGE1 in inhibiting extracellular matrix production could be due to its metabolite PGE0.

Alprostadil↗
PubMed1995

[The treatment of obstructive hypertrophic myocardiopathy refractory to medical therapy].

Until a few years ago, therapy of refractory Hypertrophic Obstructive cardiomyopathy was mainly surgical--Morrow's myotomy/myectomy or mitral valve replacement. Despite the good results of these techniques, they are not free of mortality and morbidity. In the last years a new and promising therapy has been developed: the Dual Chamber Pacemaker. Technically easier and less invasive than surgery, this therapy has achieved better results and lower mortality and morbidity during the follow-up.

Cardiomyopathy, Hypertrophic↗
PubMed1995

Biochemistry and molecular biology of the main diagnostic antigen of Paracoccidioides brasiliensis.

The 43,000 dalton glycoprotein of Paracoccidioides brasiliensis (gp 43) is the main exocellular antigen recognized by sera from patients with paracoccidioidomycosis in a variety of serological assays. Specific conformational peptide epitopes are recognized by the human antibodies as determined by antigen deglycosylation. Procedures for the purification of the gp43 using immunoaffinity chromatography have been described. The secretion of the gp43 as a function of the growth curve, its partial aggregation with a proteolytic enzyme, ability to bind laminin, as well as to form circulating immunocomplexes in vivo could play a role in pathogenesis. Crude antigenic preparations depleted of gp43 epitopes lost their ability to elicit positive skin tests. Accordingly, the purified gp43 molecule induced delayed hypersensitivity reactions in man and infected animals, caused a T-CD4-dependent proliferation of lymph node cells from mice immunized with it, and of peripheral blood lymphocytes from an individual sensitized to P. brasiliensis by prolonged contact with the fungus. To identify the immunodominant epitopes in both humoral and cellular reactions, the gp43 gene has been cloned, sequenced, and partly expressed. It bears peptide sequences homologous to those of beta-1,3-glucanases from Candida albicans and Saccharomyces cerevisiae but has no enzymatic activity itself. The molecular weight of the unglycosylated antigen is 42,227. A single N-linked oligosaccharide chain in the gp43 contains alpha-D-mannopyranosyl, beta-D-galactofuranosyl and N-acetylglucosaminyl units with the predominant ratio of 10:2:2, and characteristics of a high mannose type.

Amino Acid Sequence↗
PubMed1995

The effect of NO/EDRF and monocytes/macrophages on LDL-oxidation.

Beside prostaglandin (PG) I2 and tissue plasminogen activator (tPA), nitric oxide (NO) is a key fepellant substance contributing to haemostatic balancing. The role of low-density lipoproteins (LDL) in the pathogenesis of atherosclerosis has been gaining increasing importance. It is well accepted that LDL in their modified (i.e. oxidized) form are no longer recognized by the LDL-receptor, but are taken up by cells of the arterial wall, especially macrophages, in a non-regulated manner through the so called scavenger-receptor pathway. This process leads to the formation of foam cells, the hallmark of the atherosclerotic lesion. NO is also produced in relevant amounts by macrophages. The interaction of NO and LDL with macrophages is thus of key importance in the onset of early lesions. While oxidized LDL (oxLDL) are resulting in a decreased NO availability, NO seems to prevent LDL-oxidation. In contrast, however, in the presence of superoxides oxidation may result. All these potential actions have to be discussed in view of the extremely short half-life of NO indicating that these actions are restricted most likely to the local site of biosynthesis being dependent on the actual concentration, the duration of availability and the presence of transition metals. These findings indicate that NO may play a dual pro- and antiatherosclerotic role being dependent on local factors only.

Animals↗
PubMed1994

Influenza and vaccinia viruses expressing malaria CD8+ T and B cell epitopes. Comparison of their immunogenicity and capacity to induce protective immunity.

We compared the effectiveness of several recombinant influenza and vaccinia viruses to induce a malaria-specific immune response. The CD8+ T cell epitope of the circumsporozoite (CS) protein of Plasmodium yoelii, a rodent malaria parasite, was expressed in two distinct influenza virus proteins, the hemagglutinin and the neuraminidase. These recombinant viruses were found to be equally efficient at inducing CS-specific CD8+ T cells in mice. A third recombinant virus, which expresses a B cell epitope of the CS protein, induced neutralizing anti-sporozoite Abs. Expression in the same recombinant virus of the CD8+ T cell epitope and of the B cell epitope did not impair the capacity of this recombinant virus to induce malaria-specific CD8+ T cells and neutralizing Abs. The immunogenicity of a vaccinia virus, expressing the entire CS protein, was compared with that of a highly attenuated vaccinia strain expressing the same protein and with that of another vaccinia virus expressing only the CD8+ T cell epitope. All three vaccinia virus recombinants elicited CS-specific CD8+ cells and a potent inhibitory response against pre-erythrocytic stages of malaria parasites. Optimal levels of anti-sporozoite Abs, inhibition of liver stage development, and protection against malaria infection resulted from repeatedly immunizing the animals with recombinant influenza viruses followed by boosters with a recombinant vaccinia virus. These findings support the concept that live viral vectors expressing the appropriate proteins and/or epitopes can be used as promising vaccine candidates.

Amino Acid Sequence↗
PubMed1994

Endogenous Fusarium endophthalmitis in a patient with acute lymphocytic leukemia.

Endogenous fungal endophalmitis is an uncommon complication of systemic mycosis. Only a few cases involving Fusarium have been reported, most with unfavorable visual outcomes. We examined a 31-year-old woman with acute lymphocytic leukemia who developed sudden visual loss in her right eye. A dense, white placoid infiltrate was present in the right macula extending into the vitreous. An iris nodule and hypopyon were present in the left eye. A vitreous aspirate of the right eye was positive for Fusarium species. The patient progressively lost vision despite amphotericin B and 5-fluorocytosine therapy. She died from bronchopneumonia, fungemia, and multisystem failure. Histopathologic study disclosed a panophthalmitis with Fusarium organisms invading all the ocular coats in the right eye. Leukemic infiltrates were present in the left iris, anterior chamber, and trabecular meshwork. The ocular destructiveness of Fusarium may be caused by marked mycotic vascular invasion and occlusion with consequent infarction and necrosis of ocular tissues.

Adult↗