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Biomedical subjects

M Barbosa

Publications and source records attributed to M Barbosa.

At least 19 recordsLinked to original sources
PubMed2001

Comparative effects of nacre water-soluble matrix and dexamethasone on the alkaline phosphatase activity of MRC-5 fibroblasts.

In this study we demonstrate, for the first time, that dexamethasone and BMP-2 stimulated alkaline phosphatase (ALP) activity in MRC-5 fibroblasts, a cell line derived from human fetal lung. Previously we reported that the water-soluble matrix (WSM) of nacre obtained from the inner shell layer of the oyster Pinctada maxima, promoted an increase in ALP activity that was dose-dependent. In this work, we show that the effect of WSM is also time-dependent. As a comparison, the effect of WSM was also tested in bone marrow stromal cells because marrow and other bone surface-derived osteoblast stem cells have the inherent direct potential for osteogenesis. WSM promotes cell proliferation and ALP activity when tested with bone marrow cells in concentrations between 135 and 540 microg protein/mL. The effect of WSM on ALP activity of bone marrow stromal cells is similar to that obtained by dexamethasone. These results imply that MRC-5 fibroblasts respond to differentiating factors that promote osteoblastic phenotype in bone-derived cell cultures.

Alkaline Phosphatase↗
PubMed2001

Acetylcholinesterase and butyrylcholinesterase histochemical activities and tumor cell growth in several brain tumors.

BACKGROUND: The hydrolysis enzymes of the acetylcholine, acetylcholinesterase, and butyrylcholinesterase are involved in non-cholinergic functions such as proliferation processes and cellular adhesion. These enzymes have been found in several tumors other from brain tumors. METHODS: Thirty fresh brain tumor specimens were obtained from biopsies taken during neurosurgical procedures. The specimens were cut in two parts, one designated for routine histopathological control and the other for histochemical and growth studies. The formalin fixed specimens were serially cut at 10 microm in a freezing cryostat, mounted in gelatin-coated slides, and processed for sensitive histochemical detection of acetylcholinesterase and butyrylcholinesterase. The other specimens were processed for a HMEM cell growth culture. RESULTS: The results show the coexistence of acetylcholinesterase and butyrylcholinesterase in all tumors studied. Type II and III gliomas and oligodendrogliomas show moderate activity of both cholinesterases, whereas in type IV glioma and meningiomas the labeling of both cholinesterases was high. In the craniopharyngiomas a high acetylcholinesterase activity was observed and low level of butyrylcholinesterase labeling. The cell growth was high only in the cases in which butyrylcholinesterase activity was high, such as type IV glioma. In type II and III gliomas, oligodendroglioma, and craniopharyngioma the growth rate was slow. CONCLUSIONS: These results could indicate a possible relationship between the presence of butyrylcholinesterase and acetylcholinesterase in brain tumor tissue and cellular proliferation in tumorigenesis.

Acetylcholinesterase↗
PubMed2001

Postnatal development of cholinergic system in mouse basal forebrain: acetylcholinesterase histochemistry and choline-acetyltransferase immunoreactivity.

The distribution of acetylcholinesterase histochemistry and choline-O-acetyltransferase immunohistochemistry in the basal forebrain was studied in newborn mice (P0) and until 60 days of postnatal life (P60). A weak acetylcholinesterase activity was found at P0 and P2 in the anterior and intermediate parts of the basal forebrain, and higher in the posterior region. The intensity of labeling, neuronal size and dendritic growth seems to increase progressively in all regions of basal forebrain from P4 to P10. The AChE+ cell count shows that in the anterior portion of the magnocellular basal nucleus the number of cells does not vary significantly from birth to the second month of postnatal life. However, in the intermediate and posterior portions of the nucleus the mean number of labeled cells increases significantly from birth to the end of the second week of postnatal life (P13). The choline-acetyltransferase immunoreactivity appears only detectable at the end of the first week (P6) as a slight immunoreaction, which increases progressively in intensity at P8, and at P10 seems to attain the same intensity of labeling found at P60. These results seem to indicate that the acetylcholinesterase could have a non-classic cholinergic role in the first stages of postnatal development, acting as a growth and cellular differentiation factor.

Acetylcholinesterase↗
PubMed2001

Choroid plexus tumours: a surgically treated series.

Choroid plexus tumours-carcinomas and papillomas are rare, especially in adults, and they pose some problems in their diagnosis and management. We have reviewed a series of nine cases from our institution surgically treated during the last 18 years. Their clinical charts, neuroradiological examinations, surgical technique, neuropathology and follow-up were analysed. In only one case total removal proved to be impossible, but even in cases of total removal recurrence appeared in two cases (one carcinoma and one papilloma). Morbility is especially associated with posterior fossa tumours. These rare tumours are managed surgically. They are usually associated with hydrocephalus, and it is difficult to forecast whether or not permanent CSF drainage will be required. A long-term follow-up is needed in patients with this type of tumour.

Adolescent↗
PubMed2000

Postnatal development of the basal forebrain cholinergic projections to the medial prefrontal cortex in mice.

The postnatal development of basal forebrain cholinergic projections to the medial prefrontal cortex in mice was analyzed by means of the double labeling track-tracing study. The tracer was injected into the medial prefrontal cortex of mice, on the day of birth (P0) to 60 days after birth. The total number of basal forebrain neurons increased from P4 to P8, and began to decrease until P13 (52.9% vs. the maximal average (P8)). After P13, the mean average remains stable up to P60. On the other hand, differential pattern of frontocortical projections of the anterior, intermediate, and posterior regions can be observed.

Acetylcholinesterase↗
PubMed2000

Concept, design and fabrication of smart orthopedic implants.

Extensive clinical experience has been built up using orthopaedic implants instrumented with strain gauges connected to a Wheatstone bridge by means of percutaneous leads. This research showed the medical relevance of the monitoring of the deformation of implants as a powerful tool to evaluate nursing and rehabilitation exercises, for tracing dangerous overloads and anticipating implant failure and also to observe the healing process. The IMPACT 3500 project focuses on the instrumentation of femoral implants with on board sensors: regular Benoist-Girard implants have been modified, to contain a 'sensing cell', and thoroughly tested in vitro and in vivo. The implant deformations are measured with resistive strain gauges, and the signal is transferred to a personal computer for processing and display, via a hard wired connection, or via a telemetry system. Two fully implantable wireless designs, called Linkstrain and Sealstrain, are powered from the outside by magnetic induction. As Sealstrain contains the whole telemetric system in its cavity, the highest miniaturization was required; this seriously deteriorates the efficiency of the inductive power link.

Biocompatible Materials↗
PubMed1998

Forskolin induces U937 cell line differentiation as a result of a sustained cAMP elevation.

The present study examines the effects of forskolin on U937 cell differentiation. We recently reported that dibutyryl cAMP (dbcAMP), but not cAMP-elevating agents such as histamine, promotes U937 cell differentiation. cAMP production elicited by stimulation of histamine H2 receptors showed a rapid, homologous desensitization, which might explain the dissimilar responses to histamine and dbcAMP. Forskolin induced an increase in cAMP levels in a concentration-dependent manner (EC50=30 microM) for an extended period of at least 24 h. Forskolin but not histamine (up to 100 microM), also inhibited cell growth in a dose-dependent fashion (EC50=22 microM). After 3 days of incubation, 75 microM forskolin induced U937 cell differentiation as judged by an increased rate of reduction of nitrobluetetrazolium (mean+/-S.E.M.: 21.3+/-6.6% in treated cells vs. 3.2+/-1.9% in the control group, P < 0.001) and an augmented chemotactic response to complement 5a (C5a) (33.2+/-5.9% in forskolin-treated vs. 0.34+/-0.12% in control cells, P < 0.01). Furthermore, c-Myc levels decreased following forskolin treatment, while the histamine H2 receptor agonist dimaprit had no effect. We conclude that forskolin induces U937 cell differentiation through a sustained rise in cAMP levels.

Antigens, Neoplasm↗
PubMed1998

HTLV-I Tax protein binds to MEKK1 to stimulate IkappaB kinase activity and NF-kappaB activation.

NF-kappaB, a key regulator of the cellular inflammatory and immune response, is activated by the HTLV-I transforming and transactivating protein Tax. We show that Tax binds to the amino terminus of the protein kinase MEKK1, a component of an IkappaB kinase complex, and stimulates MEKK1 kinase activity. Tax expression increases the activity of IkappaB kinase beta (IKKbeta) to enhance phosphorylation of serine residues in IkappaB alpha that lead to its degradation. Dominant negative mutants of both IKKbeta and MEKK1 prevent Tax activation of the NF-kappaB pathway. Furthermore, recombinant MEKK1 stimulates IKKbeta phosphorylation of IkappaB alpha. Thus, Tax-mediated increases in NF-kappaB nuclear translocation result from direct interactions of Tax and MEKK1 leading to enhanced IKKbeta phosphorylation of IkappaB alpha.

Animals↗
PubMed1998

Regulation of synoviocyte proliferation, apoptosis, and invasion by the p53 tumor suppressor gene.

Recent studies show that 1) the p53 tumor suppressor protein is overexpressed by rheumatoid arthritis (RA) synovium and fibroblast-like synoviocytes (FLS) and 2) somatic mutations previously identified in human tumors are present in RA synovium and FLS. We have hypothesized that abnormalities in p53 can contribute to chronic destructive RA synovitis. To understand the functional consequences of p53 abnormalities in FLS, RA and normal FLS expressing wild-type p53 were transduced with a retroviral vector encoding the human papilloma virus 18 E6 gene, which inactivates endogenous p53 protein. Three RA and one normal FLS lines were infected with recombinant retrovirus encoding the neomycin resistance gene (neo) or E6+neo. FLS proliferation, apoptosis, and invasion was studied in E6, neo, and uninfected parental strains (PS). The growth rate for E6 was significantly increased with a sixfold increase in cell number after 7 days compared with a twofold to threefold increase in neo and PS. When FLS were treated with cytokines, proliferative response of E6, neo, and PS to interleukin-1 and transforming growth factor-beta were similar. However, response to platelet-derived growth factor was significantly greater in E6 FLS compared with neo or PS. Apoptosis was studied by incubating FLS with sodium nitroprusside as a source of nitric oxide or hydrogen peroxide for 8 hours and examining DNA fragmentation and E6 cells were significantly less susceptible to cell death. In addition, E6 FLS were more invasive into cartilage extracts than neo or PS using an in vitro cell invasion assay. These data suggest that p53 is a critical regulator of FLS proliferation, apoptosis, and invasiveness. Abnormalities of p53 function might contribute to synovial lining expansion and joint destruction in RA.

Apoptosis↗
PubMed1997

IKK-1 and IKK-2: cytokine-activated IkappaB kinases essential for NF-kappaB activation.

Activation of the transcription factor nuclear factor kappa B (NF-kappaB) is controlled by sequential phosphorylation, ubiquitination, and degradation of its inhibitory subunit IkappaB. A large multiprotein complex, the IkappaB kinase (IKK) signalsome, was purified from HeLa cells and found to contain a cytokine-inducible IkappaB kinase activity that phosphorylates IkappaB-alpha and IkappaB-beta. Two components of the IKK signalsome, IKK-1 and IKK-2, were identified as closely related protein serine kinases containing leucine zipper and helix-loop-helix protein interaction motifs. Mutant versions of IKK-2 had pronounced effects on RelA nuclear translocation and NF-kappaB-dependent reporter activity, consistent with a critical role for the IKK kinases in the NF-kappaB signaling pathway.

Cell Cycle Proteins↗
PubMed1997

[Opinion of alumni about the teaching of nursing diagnosis according to North American Nursing Diagnosis Association].

In accordance to North American Nursing Diagnosis Association (NANDA), nursing diagnosis is a clinical judgement of the individual, family or community answers to the vital process or to the actual or potential health problems. These gives the basis for the intervention selection by which the nurse is responsible. Believing in the importance of nursing diagnosis, its teaching was introduced 4 years ago in the subjects of Woman s Health Assistance and Perinatal Nursing, in the 6o. period of the undergraduate course in nursing at UNICAMP. Aiming at evaluating these experience, we proposed to get the students opinion and obtain subsides to perfect teaching. Teoric teaching of 4 hours was given and it was indicated the basic bibliography. The supervised practical application was developed during 21 hours in a neonatal unit and 45 hours in health centers. At the end of the subjects, 16 students answered a form with closed and open questions. All the students considered valid the study of the nursing diagnoses. Most of the students considered more proper to introduce the teaching in the 3o. semester, when the nursing basic procedures is begun. As to the difficult of learning in the use of diagnoses, 68.7% of the students reported a difficult level higher to 25% and lower to 75%. The students group considers that the study of nursing diagnoses brought modifications in its concept of nursing assistance.

Attitude of Health Personnel↗
PubMed1997

[Educational program in universal precaution measures: a methodological approach].

An updating program on measures of universal precautions (M.U.P.) was developed at the Center of Whole Care of Woman's Health (Centro de Atenção Integral à Saúde da Mulher-CAISM). These measures and the procedures in the case of work accident were published in a booklet. First, servants should be aware of the matter of stress and its influence on the quality of life. Then, updating was carried through encouraging the reflection on the consequences of the non-adoption of M.U.P. The answers to 286 pre-tests and 242 post-tests were analyzed and the results showed a significantly higher index of correct answers (p < 0.01), mainly regarding the appropriate use of glove.

Education, Nursing↗
PubMed1997

[Incessant atrial tachycardia and peripartum cardiomyopathy--a therapeutic challenge].

Peripartum cardiomyopathy is an uncommon cause of heart failure but with serious prognosis. We report the case of a patient with peripartum cardiomyopathy presenting acute heart failure (severe biventricular systolic failure) and incessant atrial tachycardia, a rare arrhythmia difficult to control, that was responsible for cardiogenic shock, fetus death and multiple organ failure: renal failure (hemodialysis during 17 days), respiratory and hepatic failure and ischemic acute cholecystitis (treated surgically). After emergency cesarean section, heart rate control was obtained only after administering verapamil. Progressive clinical improvement with total recovery of hepatic and renal functions followed under treatment with vigorous multiple organ support. Six months after referral, the patients is doing well with normal daily life controlled with conventional therapy for heart failure, in stable sinus rhythm. Echocardiography shows a dilated left ventricle with partial resolution of systolic dysfunction rhythm. Echocardiography shows a dilated left ventricle with partial resolution of systolic dysfunction. The use of verapamil in severe biventricular systolic failure is discussed.

Cardiomyopathies↗
PubMed1994

Surgical repair of transposition of great arteries and total anomalous pulmonary venous return to the coronary sinus (TGA with TAPVR).

The association of transposition of the great arteries (TGA) and total anomalous pulmonary venous return (TAPVR) is very rare; we report one case of this malformation with an intracardiac type of TAPVR draining into the coronary sinus. The surgical repair was performed directing the coronary sinus blood flow to the tricuspid valve. The proximity of the anatomical structures allowed an intra-atrial patch repair similar to a modified Mustard procedure. In the postoperative period the child developed low cardiac output for 2 days, requiring inotropic support and mechanical ventilation. Her recovery was otherwise uneventful. The postoperative echocardiogram showed an intact repair with perfect flow through the patch from the pulmonary veins to the right ventricle. Almost 2 years after surgery, the patient underwent cardiac catheterization that showed integrity of the surgical repair with normal pressures in all heart chambers. To our knowledge this is the first report in the medical literature of surgical treatment of this association.

Coronary Circulation↗
PubMed1992

Severe haemolytic disease in an infant born to an Rh(null) proposita.

A 35-year-old Brazilian woman (gravida 4, para 2) was delivered of a severely anaemic child whose cord red blood cells had a strongly positive direct antiglobulin test and who required two exchange transfusions within 24 h of birth. Because of the emergency of the situation and the lack of a local immunohaematology reference laboratory, the phenotype of the mother and the specificity of the relevant antibody could not be determined. Hence, compatible blood was not immediately available and the infant had to be given repeated exchange transfusions with incompatible group 0 Rh-negative blood. The infant is now healthy and thriving. The mother's red cells were subsequently found to lack all the antigens of the Rh system, and her serum reacted with all red cell samples except those of two unrelated Rh(null) individuals. Her serum gave high titres (i.e. 1,024-4,096) by the indirect antiglobulin test against red cells of normal Rh phenotype, as well as against cells with partially deleted Rh phenotypes (titres = 128-512 with -D-/-D- and .D./.D. samples, respectively), and was extremely active in antibody-dependent cell-mediated cytotoxicity and monocyte monolayer assays against red cells of normal Rh phenotypes.

Adult↗
PubMed1990

[Use of coronary angioplasty in acute myocardial infarction without previous use of thrombolytic agents. Analysis of 201 patients].

PURPOSE: To evaluate the experience with the use of primary PTCA in the set of acute myocardial infarction (AMI) without the previous administration of thrombolytic agents. PATIENTS AND METHODS: Two hundred and one patients with AMI, aged 35 to 86 years (mean = 57.2). There were 83.5% men. Twenty patients were older than 70 years and 48.2% had an anterior AMI. PTCA was performed early in the AMI, with a delay no longer than 12 hours. In 95%, it was done solely to the infarct related artery. Seventy percent patients were in Killip class I, 21% in class II, and 8% in classes III and IV (more than 50% of this subset of patients were in cardiogenic shock). RESULTS: Primary success was achieved in 84.5%. In hospital mortality was 5.9%, and there were 7% reinfarctions. Among the 84 patients who underwent a late cinecoronariography study, there were 19% restenosis and 8.3% reocclusions. In the long term follow up 75% were asymptomatic. Repeat PTCA was required in 10.2% of the cases, late coronary surgery was performed on 10.8% of the patients, and post-hospital cardiac mortality was 8.8% during an average follow up of 28 months (range 2-72 months). CONCLUSION: Primary PTCA is a effective way of reperfusion in the AMI, with a high primary success, low complications rate and without any major contraindications.

Adult↗