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Biomedical subjects

M A Teixeira

Publications and source records attributed to M A Teixeira.

At least 19 recordsLinked to original sources
PubMed2006

Effects of an individually ventilated cage system on the airway integrity of rats (Rattus norvegicus) in a laboratory in Brazil.

The ventilation method used in the management of laboratory rats is important in maintaining their health. Rats kept under general diluting ventilation (GDV) are exposed to high levels of pollutants present in the environment (dust, airborne bacteria, etc.) or those pollutants produced by animal metabolism and excretion inside the boxes (e.g. ammonia and carbon dioxide). These pollutants may contribute to respiratory pathologies. An alternative experimental ventilation system for laboratory animal housing using intracage ventilation technology (individually ventilated cage system, IVC) was developed. In this system, ammonia levels decreased and rats exhibited better reproductive performance and a lower incidence of pneumonia than rats maintained under GDV. Using two different levels of air speed (0.03-0.26 m/s: IVC(1); 0.27-0.80 m/s: IVC(2)), the effects of IVC were compared with GDV (control) in Wistar rats in terms of respiratory mucus properties, on the nasal epithelium (as measured by quantitative morphometry) and on the lungs (as determined by the cellular composition obtained by bronchoalveolar lavage). Mucus of the respiratory system was evaluated using the following techniques: rheology (viscoelasticity) by microrheometer, in vitro mucociliary transportability (frog palate) and contact angle (an indicator of adhesivity). Also, membrane transepithelial potential difference was measured as a biomarker of airway integrity. After bedding was changed, ammonia concentrations inside the cages on day 3 were significantly higher for GDV than for IVC(1) and IVC(2). The potential-difference values for IVC(1), IVC(2) and GDV in the epiglottis and in the trachea also showed differences. Although some significant differences were observed across the three groups in counts of some cell types, the intragroup results were highly variable among individuals and inconsistent between sexes. No significant differences in the other parameters were found across groups. These results establish that rats maintained under GDV in relatively unregulated conditions are exposed to factors that can lead to deleterious effects on the ciliated epithelium of the airways, and that these effects can be prevented by the use of IVC.

Air Pressure↗
PubMed2002

Cd8(+)/V beta 5.1(+) large granular lymphocyte leukemia associated with autoimmune cytopenias, rheumatoid arthritis and vascular mammary skin lesions: successful response to 2-deoxycoformycin.

We report a case of CD8(+)/V beta 5.1(+) T-cell large granular lymphocyte leukemia (T-LGL leukemia) presenting with mild lymphocytosis, severe autoimmune neutropenia, thrombocytopenia, polyarthritis and recurrent infections with a chronic disease course. Immunophenotyping showed an expansion of CD3(+)/TCR alpha beta(+)/CD8(+bright)/CD11c(+)/CD57(-)/CD56(-) large granular lymphocytes with expression of the TCR-V beta 5.1 family. Southern blot analysis revealed a clonal rearrangement of the TCR beta-chain gene. Hematopoietic growth factors, high dose intravenous immunoglobulin and corticosteroids were of limited therapeutic benefit to correct the cytopenias. During the disease course, the patient developed a severe cutaneous leg ulcer and bilateral vascular mammary skin lesions. Treatment with 2-deoxycoformycin resulted in both clinical and hematological complete responses, including the resolution of vascular skin lesions. Combined immuno-staining with relevant T-cell associated and anti-TCR-V beta monoclonal antibodies proved to be a sensitive method to assess the therapeutic effect of 2-deoxycoformicin and to evaluate the residual disease.

Aged↗
PubMed2001

Are some breast carcinomas polyclonal in origin?

This editorial comments on the important study by Going et al. published in the present issue of the Journal [1]. Using a molecular genetic assay based on the X-chromosome inactivation principle, they found that 4 out of 12 breast carcinomas examined exhibited what the authors call "clonal mosaicism" that is, two or more monoclonal samples were mosaic (polyclonal) in respect of X chromosome inactivation between separate, morphologically homogeneous tumour areas. The authors very carefully discuss potential methodological errors that could have led to this surprising finding, which seems to run counter to the almost unanimously held conviction that carcinomas are monoclonal in origin, but none of these potential errors would explain the results. As often in such situations, the authors prudently state that further studies using independent analytical techniques are necessary to find out whether a significant proportion of mammary carcinomas are indeed polyclonal. However, there already exists a substantial body of evidence from cytogenetic studies of breast cancers indicating that many of them are polyclonal. Although there is still room for interpretation and some doubt remains as to exactly which role should be ascribed to the observed clonal heterogeneity in our models of carcinogenesis, it seems obvious that more attention than before ought to be paid to this now well documented fact.

Breast Neoplasms↗
PubMed2001

Association of CD4+/CD56+/CD57+/CD8+(dim) large granular lymphocytic leukemia, splenic B-cell lymphoma with circulating villous lymphocytes, and idiopathic erythrocytosis.

In this paper we report a rare association of a splenic marginal zone B-cell lymphoma with villous lymphocytes and a T-cell large granular lymphocytic leukemia coexpressing CD4 and CD8 as well as CD56 and CD57 natural killer-associated markers in an asymptomatic patient investigated because of an occasional finding of erythrocytosis and leukocytosis in routine blood analysis. We also discuss the possible reasons for this particular association.

Aged↗
PubMed2001

Evaluation of reproductive indices in rats (Rattus norvegicus) housed under an intracage ventilation system.

A cabinet with an intracage ventilation system (ICV) was developed, and rats (Rattus norvegicus) were exposed to five air-speed levels (ICV 1, 0.03 to 0.12 m/s; ICV 2, 0.13 to 0.18 m/s; ICV 3, 0.19 to 0.33 m/s; ICV 4, 0.34 to 0.51 m/s, and ICV 5, 0.52 to 0.80 m/s) to evaluate optimal rates for ventilation and to assess whether reproductive performance differed at the various air speeds. Our results showed that rats housed under ICV conditions tolerate a continuous air flow into the cage. This condition did not impair the reproductive performance in any of the groups. In fact, air-speed levels ranging from 0.19 to 0.51 m/s (ICV3 and ICV4 conditions) led to a greater number of and more uniform litters with decreased mortality rates compared with those of the control group.

Animals↗
PubMed1999

[Syndrome of Munchausen and pseudoparaplegia. Case report].

We present a 36 years old female, with a 8 years history of "paraplegia", who was admitted to our department to have "some needles withdrawn" from her back. She referred previous admittances to general and psychiatric hospitals in order to treat several episodes of renal failure, combined with other clinical conditions like pulmonary tuberculosis and esophagus, ovary and breast cancer. On the psychiatric evaluation, we found a patient who seemed to be indifferent to her disease, giving accurate and very elaborated description of her symptoms. She was always complaining about previous medical therapies. She moved her both legs simultaneously, without any impairment on reflexes and sensibility. We did not find evidence of tumor processes. The electromyography, cranial CT scan, abdominal ultrasound scan and chest X-ray were normal. Lumbosacral X-ray and CT scan showed 16 sewing needles widespread in the lumbosacral soft tissues. A diagnosis of Munchausen syndrome was formed. After a 15-day trial of anti depressive drug, physiotherapy and psychotherapy, her clinical status significantly improved, reverting its neurological picture after treatment.

Adult↗
PubMed1997

Relative impact of HLA phenotype and CD4-CD8 ratios on the clinical expression of hemochromatosis.

Hemochromatosis is a hereditary iron-overload disease linked to HLA. The clinical expression of hemochromatosis is influenced by sex and age. However, other factors must account for the notorious heterogeneity of expression of the disease independent of sex, age, and HLA phenotype. The present study attempts to clarify some of these additional factors based on exhaustive statistical analysis of data collected from 43 selected patients with hemochromatosis. The statistical analysis focused on three groups of variables: the first group included variables reflecting the clinical expression of the disease; the second group represented the biochemical and hematological values at the time of diagnosis; and the third group consisted of the independent variables sex, age, HLA phenotype, and T-cell subset profile, i.e., the percentages and total numbers of CD4+ and CD8+ cells and the CD4-CD8 ratios. The results show that the relative expansion of the two main T-cell subsets, in the context of the HLA phenotype, correlates significantly with the clinical expression of hemochromatosis and the severity of iron overload. The present findings substantiate further the postulate that T cells have a role in the regulation of iron metabolism.

Adult↗
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↗
PubMed1996

Theoretical dynamics of experimental populations of introduced and native blowflies (Diptera:Calliphoridae).

Equilibrium dynamics in experimental populations of Chrysomya megacephala (F.) and C. putoria (Wiedemann), which have recently invaded the Americas, and the native species Cochliomyia macellaria (F.), were investigated using nonlinear difference equations. A theoretical analysis of the mathematical model using bifurcation theory established the combination of demographic parameters responsible for producing shifts in blowfly population dynamics from stable equilibria to bounded cycles and aperiodic behavior. Mathematical modeling shows that the populations of the 2 introduced Chrysomya species will form stable oscillations with numbers fluctuating 3-4 times in successive generations. However, in the native species C. macellaria, the dynamics is characterized by damping oscillations in population size, leading to a stable population level.

Animals↗
PubMed1995

Self-consciousness Scale: a Brazilian version.

The aim of this study was to examine the applicability of a Brazilian version of the Self-consciousness Scale to university students. Factorial structure, subscale intercorrelations, and normative data obtained with 182 subjects are reported. These results suggest that the proposed model of self-consciousness is applicable in the Brazilian culture, although some significant sex differences were found for two of the scales. Reliability tests and the factorial validity of the scale showed that this version still needs refinement to be used as a reliable research tool.

Adolescent↗
PubMed1993

A dammarane-type saponin from the roots of Ampelozizyphus amazonicus.

A new C31 dammarane-type triterpenoid saponin has been isolated from the roots of Ampelozizyphus amazonicus. Its structure was elucidated to be ampelozigenin-15 alpha-O-acetyl- 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside by 1D and 2D NMR spectroscopic methods, and by chemical transformations. Ampelozigenin is a novel triterpene, (20R,22R)-16 beta,22:16 alpha, 30-diepoxydammar-24(24')- methylene-3 beta, 15 alpha, 20-triol.

Carbohydrate Sequence↗
PubMed1992

[Pathogenesis of mitral valve prolapse in patients with chronic Chagas disease: study of papillary muscle myocarditis].

PURPOSE: Studying the mitral valve in chronic Chagas' heart disease, searching a possible cause effect relationship between this condition and valve prolapse. METHODS: Seventeen hearts were surveyed from individuals exhibiting chronic chagasic cardiopathy, 11 males and 6 females, aged between 31-84 (average 54) years. The hearts came from necropsies carried out until a year before. Properly preserved samples were analyzed macro and microscopically. Fragments were excised from the mitral valve papillary muscles, anterior, lateral and posterior regions of the left ventricle, interventricular septum, free wall of right ventricle and atrium walls. RESULTS: Chronic myocarditis was found ill all the samples (mild in 6 of them, moderate in 7 and severe in 4). Also, the papillary muscles exhibited myocarditis in all of the samples, and in 15 of them the degree of severity was equal to or superior than the observed in degree other regions of the heart. CONCLUSION: The chronic chagasic cardiopathy, the papillary muscle constitute a frequent site of myocarditis. This fact must be held in mind when one discusses the pathogenesis of the prolapse of the valve.

Adult↗
PubMedDate not supplied

Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK-cell subsets and its impact on the understanding of their tissue distribution and functional properties.

In the present study we have compared the immunophenotypic characteristics of the CD56+lo and CD56+hi NK-cell subsets in a group of normal healthy adults. Our results show that CD56+hi NK-cells display greater light-scatter properties than CD56+lo NK-cells at the same time they have higher levels of CD25 and CD122 IL-2 chains, together with a higher reactivity for HLA-DR and CD45RO and lower levels of CD45RA, supporting that, as opposed to the majority of the CD56+lo population, CD56+hi NK-cells might correspond to a subset of activated circulating NK-lymphocytes. Higher expression of the CD2 and CD7 costimulatory molecules found for the CD56+hi NK-cells would support their greater ability to respond to various stimuli. In addition, CD56+hi NK-cells expressed higher levels of several adhesion molecules such as CD2, CD11c, CD44, CD56, and CD62L compared to CD56+lo NK-cells, supporting a particular ability of these cells to migrate from blood to tissues and/or a potential advantage to form conjugates with target cells. Interestingly, CD56+lo and CD56+hi NK-cells showed a different pattern of expression of killer receptors that might determine different activation requirements for each of these NK-cell subsets. For instance, absence or low levels of CD16 expression might explain the lower antibody-dependent cytotoxicity activity of CD56+hi NK-cells. On the other hand, the virtual absence of expression of the CD158a and NKB1 immunoglobulin-like and the greater reactivity for the CD94 lectin-like killer receptors on CD56+hi in comparison to CD56+lo NK-cells might determine different MHC-class I specificities for both NK-cell subsets, a possibility that deserves further studies to be confirmed.

Adult↗
PubMedDate not supplied

[Women caring for women: a study at the "Viva Maria" shelter, Porto Alegre, Rio Grande do Sul, Brazil].

This research was conducted in Porto Alegre, Rio Grande do Sul, with a sample of battered women selected from a government shelter called the "Casa Viva Maria". We analyzed data on 110 women staying at the shelter during the previous two years (January 1996-June 1998). The profile of the women was as follows: abused women were young (mean age 29 years), all had low socioeconomic status, 12% were illiterate, 21% were black, 80% reported frequent abuse by their partners, and 18% had returned to violent homes. The researchers visited 34 former lodgers from the shelter and invited them to participate in a series of evaluation workshops. A total of 118 persons, including mothers and children, attended three evaluation meetings. During this process, researchers encouraged participants to express opinions, perceptions, and feelings about their past experience in the shelter and their own concept of violence. Finally, a focal group was organized with the "Viva Maria" staff members. Female workers reported how their job had been helpful for their personal development and had helped change their own lives.

Adolescent↗
PubMedDate not supplied

Aggressive natural-killer cell lymphoma presenting with skin lesions, breast nodule, suprarenal masses and life-threatening pericardial and pleural effusions.

We report the clinical and laboratory findings of a patient with an aggressive Epstein-Barr virus positive CD2+/CD56+ natural killer-cell lymphoma with a high mitotic activity and complex chromosomal abnormalities presenting with life-threatening pericardial and pleural effusions, disseminated skin lesions, breast nodule and large suprarenal masses. The clinical course was characterized by resistance to chemotherapy and relapsing pericardial and pleural effusions with respiratory and haemodynamic failure. Death occurred 4 months after the first manifestations of the disease as a consequence of cardiac tamponade.

Adult↗