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Biomedical subjects

M A Costa

Publications and source records attributed to M A Costa.

At least 73 records · Page 4Linked to original sources
PubMed1998

[The role of external radiotherapy in the treatment of medullary carcinoma of the thyroid].

Medullary carcinoma of the thyroid represents 3 to 10% of all thyroid cancers. Surgery is the main treatment. External beam radiotherapy has a fundamental role in the treatment of residual disease following surgery, in cases of cervical node involvement, and in unresectable tumors. Between 1975 and 1993, 12 patients with medullary carcinoma of the thyroid were treated at the Department of Radiotherapy of the Portuguese Institute of Oncology in Oporto. Nine of these patients (75%) were male and 3 (25%) female, ranging from 24 to 80 years of age (mean = 43). All of them had residual tumor after surgery and underwent treatment with external beam radiotherapy. The follow-up period ranged from 36 to 180 months, with a median of 78 months; 8 patients (66.7%) are alive, 5 of them show no evidence of disease. Average survival was 70 months, and 4 patients (33%) died with metastatic disease. The aim of this paper is to analyse the role of external beam radiotherapy in local control of these tumors, with a brief review of the literature.

Adult↗
PubMed1997

Angiomatoid fibrous histiocytoma of the arm treated by radiotherapy for local recurrence--case report.

The Angiomatoid Fibrous Histiocytoma is a rare tumor of soft tissues, which occurs mainly in children and young adults, with low malignancy grade. It has the capacity of local recurrence, but rarely metastizes. It is frequently difficult to differentiate this from vascular tumors, namely hemangioendotheliomas and angiosarcomas, or simply organized hematomas. The authors present a case of a patient with an angiomatoid fibrous histiocytoma of the arm, treated with radiotherapy after three postsurgical recurrences.

Arm↗
PubMed1997

Mineralization in serially passaged human alveolar bone cells.

Well-characterized human bone cell cultures have been regarded as a useful tool to study bone control mechanisms and also to analyse bone/biomaterials interactions. In the present study, human alveolar bone cells were cultured in alpha-minimal essential medium (alpha-MEM) containing 10% foetal bovine serum (FBS), 50 microg/ml ascorbic acid, 10 mM sodium beta-glycerophosphate and either in the presence or in the absence of 10 nM dexamethasone (Dexa). Cultures were characterized concerning cell viability/proliferation, alkaline phosphatase (ALP), acid phosphatase (ACP) and tartraric acid resistant phosphatase (TRAP) activities, and formation of mineralized areas. Cell proliferation increased gradually for approximately 20 days. In the presence of Dexa, cells formed isolated or interconnected multilayered clusters that increased with culture time. Histochemical assays revealed strong positive reactions for ALP and calcium and phosphates deposits, mainly in relation t! o ce lls associated with the clusters. High levels of ALP activity (biochemical determination) were observed. Cells cultured in the absence of Dexa showed significantly lower ALP activity and no calcium and phosphates deposits were present. Serially passaged cells kept the proliferation rate constant but a decrease in ALP activity was observed either in the presence or in the absence of Dexa. The ability to form mineralized areas (cultures fed with Dexa) also decreased on serial subculture.

Journal Article↗
PubMed1997

Clinical factors predictive of bone marrow involvement in Hodgkin's disease.

The role of bone marrow biopsy in the staging of Hodgkin's disease is undergoing reevaluation. We have studied the relationship of clinical factors to the presence of bone marrow involvement in 130 previously untreated patients with Hodgkin's disease. The presence of fever, spleen enlargement, anemia, leukopenia, poor performance status and poor histologic subgroups were positively correlated with the presence of bone marrow involvement in the univariate analysis. In the multivariate analysis, only fever, spleen involvement, leukopenia and poor histologic subgroups were significant. The predictive value of the absence of fever in regard to the absence of bone marrow involvement was 98%. The likelihood of bone marrow involvement in the absence of all four significant factors was only 0.05%. Patients without these clinical factors should probably not be submitted to a bone marrow biopsy as part of the staging procedures performed in Hodgkin's disease.

Adolescent↗
PubMed1997

[The impact of HIV infection on the incidence of syphilis and gonorrhea at a university hospital (1985-1994)].

Syphilis and gonorrhea are two sexually transmitted diseases (STD) which still persist in spite of the existence of effective treatment. In this paper the incidence of these two diseases was evaluated between 1985-1994, a decade during which the problem of HIV infection arose. Every patient who attended the STD Program at the Hospital and was suspected of having syphilis and/or gonorrhea was clinically evaluated and was subjected to the following tests: a) search for Neisseria gonorrhoeae (Ng) and penicinilase producers (PPNG) identification, b) search for Treponema pallidum (Tp) by darkfield microscopy, c) serological studies for syphilis. From 1985 to 1991 the average of positive cases for Ng was 14.8% while from 1992 to 1994 it was 4.0% (p < 0.0001) showing a dramatic decrease between 1991 and 1992. PPNG increased from 8.7% in 1985 to 44.6% in 1988 and then slowly decreased down to 26.9% in 1994. From 1985 to 1990 the average of positive darkfield examinations was 20.7% while from 1991 to 1994 it was 12.2% (p < 0.0001). Between 1985 to 1988 syphilis serological studies showed 45.7% positive cases dropping to 34.3% between 1989 and 1994 (p < 0.0001). HIV infection appearance had a wide repercussion throughout the world generating behavioral and sexual habit changes which have probably helped to prevent these two STD. Gonorrhea incidence was also influenced by the appearance of new effective treatments, even against PPNG, such as fluorated quinolones and third generation cephalosporines. The population studied belongs to the most crowded area in Argentina, so that these observations should not be extrapolated to the rest of the country.

Adolescent↗
PubMed1997

[Value of transthoracic Doppler echocardiography in the diagnosis and management of massive pulmonary embolism].

We report the case of a 62-year-old man with massive pulmonary embolism and severe hemodynamic impairment. Transthoracic Doppler echocardiography was fundamental in confirming the diagnosis by direct visualization of intra-atrial thrombus and signs of right chamber overload. It allowed prompt administration of thrombolytic drug and follow-up monitoring. Doppler echocardiography is a non-invasive, available technique and its early application should be considered in the evaluation of patients with suspected massive pulmonary embolism.

Aged↗
PubMed1996

cDNA cloning, sequence analysis and allergological characterization of Par j 2.0101, a new major allergen of the Parietaria judaica pollen.

A clone (P2) coding for an allergen of Parietaria judaica (Pj) pollen has been isolated and sequenced from a cDNA library in lambda ZAP using a pool of 23 sera from Pj-allergic patients. The clone contained an insert of 622 nucleotides with an open reading frame of 133 amino acids (aa) and a putative signal peptide of 31 aa giving a deduced mature processed protein of 102 aa with a molecular mass of 11344 Da. The expressed recombinant protein, named rPar j 2.0101, was a major allergen since it reacted with IgE of 82% (23/28) of the sera of Pj-allergic subjects analyzed. It was shown to be a new allergen since (i) the amino acid sequence homology with the already reported recombinant allergen Par j 1.0101 was 45% and (ii) there was no cross-inhibition between rPar j 2.0101 and rPar j 1.0101. In addition, rPar j 2.0101 inhibited 35% of the specific IgE for 10-14 kDa native allergens and preincubation of sera from Pj-allergic patients with both rPar j 2.0101 and rPar j 1.0101 fully abolished the IgE recognition of the 10-14 kDa native allergen region, suggesting that these two allergens contributed to the region.

Allergens↗
PubMed1996

Isolation of proteins and nucleic acids by electrophoresis on disposable gel columns.

A simple and cheap one-step method to isolate proteins or nucleic acids by electrophoresis in disposable gel columns is reported. A disposable syringe was modified to host a gel column and an elution chamber. Starting from a crude extract of E. coli, the laboratory-made devise allowed the isolation of the maltose binding protein (MBP) fused to a recombinant allergenic molecule with a molecular mass of 58 kDa, from a mixture of several proteins. Also, plasmid DNA could be isolated from a mixture containing chromosomal DNA and RNA, avoiding the use of organic solvents. Electrophoresis was performed at 150 V, 35 degrees C, pH 8.0 and 8.3 for protein and DNA, respectively. The protein or the DNA obtained showed a yield of 80% and a purity grade of 90%, as estimated by densitometry.

ATP-Binding Cassette Transporters↗
PubMed1995

Phenotypic alterations of petal and sepal by ectopic expression of a rice MADS box gene in tobacco.

Floral organ development is controlled by a group of regulatory factors containing the MADS domain. In this study, we have isolated and characterized a cDNA clone from rice, OsMADS3, which encodes a MADS-domain containing protein. The OsMADS3 amino acid sequence shows over 60% identity to AG of Arabidopsis, PLE of Antirrhinum majus, and AG/PLE homologues of petunia, tobacco, tomato, Brassica napus, and maize. Homology in the MADS box region is most conserved. RNA blot analysis indicated that the rice MADS gene was preferentially expressed in reproductive organs, especially in stamen and carpel. In situ localization studies showed that the transcript was present primarily in stamen and carpel. The function of the rice OsMADS3 was elucidated by ectopic expression of the gene under the control of the CaMV 35S promoter in a heterologous tobacco plant system. Transgenic plants exhibited an altered morphology and coloration of the perianth organs. Sepals were pale green and elongated. Limbs of the corolla were split into sections which in some plants became antheroid structures attached to tubes that resembled filaments. The phenotypes mimic the results of ectopic expression of dicot AG gene or AG homologues. These results indicate that the OsMADS3 gene is possibly an AG homologue and that the AG genes appear to be structurally and functionally conserved between dicot and monocot.

Amino Acid Sequence↗
PubMed1995

Randomized trial comparing oral ciprofloxacin plus penicillin V with amikacin plus carbenicillin or ceftazidime for empirical treatment of febrile neutropenic cancer patients.

Aminoglycoside-containing combination therapy has been the standard empirical approach for febrile neutropenic cancer patients. With the advent of the broad-spectrum oral fluoroquinolones, it is now possible to evaluate an initial empirical alternative therapy. A prospective randomized study was conducted comparing oral ciprofloxacin plus penicillin V (group A) with amikacin plus carbenicillin or ceftazidime (group B). Main criteria for eligibility were febrile patients with solid tumor or nonlymphoblastic lymphoma, a Zubrod PS equal to 1 or 2, no diarrhea, mucositis, or long-term central venous catheter. A total of 108 consecutive neutropenic febrile episodes were randomized (5 exclusions); 55 episodes were assigned to group A and 48 to group B. Most febrile episodes were of unknown origin. There were 10 microbiologically documented episodes with two cases of bacteremia. Both regimens were well tolerated. Oral regimen was substantially cheaper than parenteral regimen. Treatment success without regimen modification was 94.5% for group A and 93.8% for group B (p = .86; CI -0.08-0.10). Oral therapy with ciprofloxacin and penicillin V is a safe alternative to standard parenteral therapy in this low-risk group of neutropenic patients, with unquestionable cost containment.

Administration, Oral↗
PubMed1995

Systemic baroreflex alterations in prehepatic portal hypertensive conscious rats.

In portal hypertensive patients and experimental models, hyperdynamic circulatory disturbances associated to a reduced peripheral resistance and an increased cardiac output appeared. The aim of this research is the study of the baroreflex system behavior partially portal vein ligated-portal hypertensive rats. Sham operated rats (S) (n = 7) and portal hypertensive rats (PH) (n = 9) were used. In anesthetized rats, catheters were introduced into a jugular vein for drug injection and into the ventral tail artery to record blood pressure and heart rate. When rats were conscious and moving freely, a bolus injection of phenylephrine hydrochloride (6 micrograms/kg) was injected in the vein. A sigmoid curve relating systolic blood pressure and heart period was dressed. We analyzed: 1) The gain or sensitivity: the slope of the regression line; 2) The threshold: systolic blood pressure at which the regression begins to be linear. The results were: mean arterial pressure (mmHg): S = 103 +/- 7; PH = 109 +/- 3; gain (ms/mmHg): S = 1.29 +/- 0.10; PH = 0.62 +/- 0.04 (p < 0.001); threshold (mmHg): S = 145 +/- 7; PH = 146 +/- 4. The baroreceptor reflex sensitivity was significantly decreased. No differences appeared in the mean arterial pressure and in the reflex threshold. It is suggested that portal hypertension induces alterations in baroreflex regulation of arterial blood pressure.

Animals↗
PubMed1994

cDNA cloning, expression and primary structure of Par jI, a major allergen of Parietaria judaica pollen.

A 659 bp cDNA clone** coding for an allergen of Pj pollen has been isolated from a lambda gt11 library, and its DNA sequence determined. The cDNA insert showed an open reading frame of 429 bp coding for an allergenic protein of 14,866 Da and a deduced amino acid sequence containing 143 residues. The expressed recombinant protein represented the major allergen Par jI since it reacted with 95% of the sera from Pj-allergic patients (n = 22) and with two Par jI-specific monoclonal antibodies. No similarity with other known DNA and protein sequences has been detected.

Allergens↗
PubMed1994

A 20 nucleotide upstream element is essential for the nopaline synthase (nos) promoter activity.

The nopaline synthase (nos) promoter is expressed in a wide range of plant cell types and regulated by various developmental and environmental factors. The nos upstream control region essential for this regulation was studied by means of synthetic oligomers using transient and stable transformation systems. Insertion of a 20 nucleotide sequence containing two hexamer motifs and a spacer region into deletion mutants lacking the upstream control region was essential for promoter activity. Mutation of one or more nucleotides of either hexamer sequence significantly altered the strength of expression of the nos promoter. Point mutations within the spacer region also strongly influenced promoter strength. Insertion of multiple copies of the 20 nucleotide sequence into the nonfunctional deletion mutants proportionally increased the promoter activity. These results suggest that this twenty nucleotide sequence is essential for the nos promoter to function. Substitution of the nos element with the ocs or 35S as-1 which contain similar hexamer motifs restored not only promoter activity but also responses to wounding, auxin, methyl jasmonate, and salicylic acid.

Amino Acid Oxidoreductases↗
PubMed1994

Long-term results with MACOP-B in the treatment of aggressive non-Hodgkin's lymphomas. The experience in Brazil.

From October 1984 to December 1989, 59 patients with aggressive non-Hodgkin's lymphomas (diffuse mixed, diffuse large cell, and immunoblastic) were treated with MACOP-B. All patients were previously untreated and most of them had advanced disease. Complete response (CR) was observed in 66%. Actuarial overall survival, failure-free survival (FFS), and relapse-free survival at 8 years were 54%, 52%, and 81%, respectively, with a median follow-up of 76 months (range: 28-92 months). The presence of B symptoms influenced significantly the CR rate, while FFS was affected by B symptoms, bone marrow involvement, and number of extranodal sites. Toxicity was high, with mucositis grade 2 or 3 occurring in 70%, leukopenia grades 3 or 4 in 80%, and death in 11.8% of the patients. MACOP-B was active in the treatment of aggressive non-Hodgkin's lymphomas, mainly in patients with few poor-prognosis factors, but other less toxic regimens would be more appropriate for this population. For poor-prognosis patients, new therapeutic modalities are necessary.

Actuarial Analysis↗
PubMed1993

C-MOPP/ABV yields good results in a public hospital population with Hodgkin disease in Brazil.

BACKGROUND: Over the last 15 years, a number of combination chemotherapy regimens have been reported to induce more than 80% complete remissions (CR) in patients with advanced Hodgkin disease (HD). Almost all such studies have been conducted in large institutions from North America and Europe. It remains to be proven, however, that those regimens are equally effective for the larger population of patients with HD who live in very different social conditions in third-world countries. METHODS: Fifty-nine patients with advanced-stage or early bulky HD were treated in two public hospitals with the C-MOPP/ABV hybrid program, in which cyclophosphamide was substituted for mechlorethamine. RESULTS: The median number of cycles administered was six, and the median follow-up was 32 months. Fifty patients (85%) reached a CR. The actuarial failure-free survival (FFS) rate was 69%, and the actuarial overall survival rate was 78% at 68 months. The only significant prognostic factor that predicted for improved FFS rate was the absence of B symptoms (P = 0.02). Overall survival was better for patients who reached a CR (P = 0.0003) and those with no systemic symptoms (P = 0.007). Toxic effects were moderate, with one treatment-related death and six episodes of serious infection. CONCLUSIONS: The target population consisted of lower-class Brazilians, many living in poor social conditions. Nevertheless, these results compare equitably with other results reported in the literature. C-MOPP/ABV is an adequate treatment for HD in third-world populations.

Adolescent↗
PubMed1993

Voltage gradient electrophoresis of nucleic acids on agarose gels.

A very simple method is described which allows the separation of DNA molecules in a wide molecular weight range (from 0.6 to about 30 kb) in the same electrophoresis agarose gel. This is based on the achievement of a voltage gradient through a simple device consisting of a Plexiglas plate placed slantwise with respect to the gel surface plane, submerged in the electrophoretic running buffer. Further applications of our system are also described.

DNA↗