Search PubMed⌕ Search

Biomedical subjects

J S Oliveira

Publications and source records attributed to J S Oliveira.

At least 19 recordsLinked to original sources
PubMed2001

Fluorescent in-situ hybridization (FISH) for BCR/ABL in chronic myeloid leukemia after bone marrow transplantation.

CONTEXT: Identification of Philadelphia chromosome or BCR/ABL gene rearrangement in chronic myeloid leukemia is important at diagnosis as well as after treatment. OBJECTIVE: To compare the results of karyotyping using fluorescent in-situ hybridization (FISH) upon diagnosis and 1 year after bone marrow transplantation in 12 patients. TYPE OF STUDY: Diagnostic test and residual disease detection. SETTING: Hematology and Hemotherapy Department, Federal University of São Paulo/Escola Paulista de Medicina, São Paulo, Brazil. SAMPLE: 12 patients with chronic myeloid leukemia at diagnosis and 1 year after bone marrow transplantation. DIAGNOSTIC TEST: Karyotyping was done in the usual way and the BCR/ABL gene-specific probe was used for FISH. MAIN MEASUREMENTS: Disease at diagnosis and residual. RESULTS: At diagnosis, 10 patients presented t(9;22)(q34.1;q11) as well as positive FISH. Two cases did not have metaphases but FISH was positive. After bone marrow transplantation, 8 patients presented normal karyotype, 1 had persistence of identifiable Philadelphia chromosome and 3 had no metaphases. Two cases showed complete chimera and 2 had donor and host cells simultaneously. FISH was possible in all cases after bone marrow transplantation and confirmed the persistence of identifiable Philadelphia chromosome clone in one patient, and identified another that did not present metaphases for analysis. Cases that showed mixed chimera in karyotype were negative for BCR/ABL by FISH. CONCLUSION: The applicability of FISH is clear, particularly for residual disease detection. Classical and molecular cytogenetics are complementary methods.

Adolescent↗
PubMed2001

Use of imposex (pseudohermaphroditism) as indicator of the occurrence of organotin compounds in Portuguese coastal waters--Sado and Mira estuaries.

Organotin compounds, including tributyltin (TBT), are a class of the most toxic xenobiotics occurring in aquatic systems. High concentration levels in waters and sediments are mainly due to their extensive use as biocides and high persistence when present in sediments under anaerobic conditions. Toxicity studies have revealed the acute effects of TBT for aquatic organisms at concentrations as low as 1 microgram/L, and the induction of imposex at levels below 0.5 ng/L TBT (as Sn). At 20 ng/L TBT (as Sn) causes sterility and is followed with the disappearance of the most sensitive neogastropods on a given shore. Imposex is the most sensitive response of all known pathological conditions for nontarget organisms following an exposure to tributyltin. In this study results are discussed that were obtained from two monitoring sites with different anthropogenic background using imposex monitoring as an indicator of TBT concentrations, as well as chemical analysis of tissue of Hinia (= Nassarius) reticulata (L.) (Gastropoda).

Animals↗
PubMed2001

An algebraic-combinatorial model for the identification and mapping of biochemical pathways.

We develop the mathematical machinery for the construction of an algebraic-combinatorial model using Petri nets to construct an oriented matroid representation of biochemical pathways. For demonstration purposes, we use a model metabolic pathway example from the literature to derive a general biochemical reaction network model. The biomolecular networks define a connectivity matrix that identifies a linear representation of a Petri net. The sub-circuits that span a reaction network are subject to flux conservation laws. The conservation laws correspond to algebraic-combinatorial dual invariants, that are called S- (state) and T- (transition) invariants. Each invariant has an associated minimum support. We show that every minimum support of a Petri net invariant defines a unique signed sub-circuit representation. We prove that the family of signed sub-circuits has an implicit order that defines an oriented matroid. The oriented matroid is then used to identify the feasible sub-circuit pathways that span the biochemical network as the positive cycles in a hyper-digraph.

Linear Models↗
PubMed2001

Cloning and overexpression in soluble form of functional shikimate kinase and 5-enolpyruvylshikimate 3-phosphate synthase enzymes from Mycobacterium tuberculosis.

Tuberculosis (TB) resurged in the late 1980s and an estimated 1.87 million people died of TB in 1997. The reemergence of tuberculosis as a public health threat, the high susceptibility of HIV-infected persons, and the proliferation of multidrug-resistant strains have created a need to develop new antimycobacterial agents. The existence of a shikimate pathway has been predicted by the determination of the genome sequence of Mycobacterium tuberculosis. The M. tuberculosis aroK-encoded shikimate kinase and aroA-encoded 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase were cloned and the enzymes overexpressed in soluble form. Overexpression was achieved without isopropyl beta-d-thiogalactoside induction, and cells grown to stationary phase yielded approximately 30% of target proteins to total soluble cell proteins. Enzyme activity measurements using coupled assays demonstrated that there was a 328-fold increase in specific activity for shikimate kinase and 101-fold increase for EPSP synthase.

Cloning, Molecular↗
PubMed2001

Cross reactivity of different specific Micrurus antivenom sera with homologous and heterologous snake venoms.

Coral snakes are the only Elapids in America. They are represented by three genera: Leptomicrurus, Micruroides and Micrurus, of which the latter are the most abundant and diversified group. Little is known about the biochemistry of Micrurus venoms due to low availability. Here, we present a study on the cross reactivity of different specific Micrurus antivenom with homologous and heterologous snake venoms in order to contribute to the generation of more efficient antiserum for therapeutic purposes. The three specific antisera tested, anti-Micrurus corallinus, anti-Micrurus frontalis, and anti-Micrurus spixii, as well as the bivalent anti-elapid venom sera, raised against a mixture (50% each) of Micrurus frontalis and Micrurus corallinus venoms, were assayed by Western Blot against Micrurus and non-Micrurus elapid venoms. An antisera raised against a recombinant alpha-neurotoxin-like protein from Micrurus corallinus venom, only reacted in Western blot with its homologous venom, indicating that this protein is specific for Micrurus corallinus coral snake.

Animals↗
PubMed2001

Diet and medication in the treatment of hyperuricemia in hypertensive patients.

OBJECTIVE: To evaluate the effects of diet and medication, either isolated or associated, on serum levels of uric acid in patients with hyperuricemia. METHODS: We studied patients from the Hypertension Unit of the University of Goias who had hyperuricemia (men > or =8.5 mg/dL and women > or =7.5 mg/dL). We divided the patients into three groups: G1 (low purine diet), G2 (low purine diet + medication), and G3 (medication only). Patients received allopurinol, 150 mg/day titrated up to 300 mg/dL when necessary. Patients were evaluated with regards to their lifestyles (diet, smoking, physical, activity, alcohol consumption), uric acid, blood pressure, use of medication, body mass index, cholesterol, and triglyceride. Follow-up took place in weeks 0 (M1), 6 (M2), 12 (M3) during the intervention and in week 36 (M4) after the study was completed. RESULTS: Fifty-five patients participated in the study, 31 women, mean age 54.4+/-10.6 years, body mass index 28.6+/-3.9 kg/m2. A similar reduction (p<0.001) in uric acid levels occurred in the three intervention groups. In week 36 (M4), after 24 weeks without intervention, a tendency toward elevation of uricemia was noted in G2 and G3, and a continuous drop in uricemia was noted in G1. No significant modifications were observed in the other variables analyzed. CONCLUSION: Considering the cost x benefit relationship, a diet low in purine should be the 1st therapeutic option for controlling hyperuricemia in patients with similar characteristic to the ones presented in this study.

Allopurinol↗
PubMed2000

Prognostic factors in non-Hodgkin lymphomas.

CONTEXT: In Hodgkin's disease, each clinical or pathologic stage can be related to the extent of the area involved and predicts the next anatomical region at risk for tumor dissemination. OBJECTIVE: To determine the best prognostic factors that could predict survival in non-Hodgkin lymphoma cases. DESIGN: A retrospective study. LOCATION: Department of Hematology and Transfusion Medicine, Universidade Federal de São Paulo - Escola Paulista de Medicina. PARTICIPANTS: 142 patients with non-Hodgkin lymphoma diagnosed between February 1988 and March 1993. MAIN MEASUREMENTS: Histological subset, Sex, Age, Race, B symptoms, Performance status, Stage, Extranodal disease, Bulk disease, Mediastinal disease, CNS involvement, BM infiltration, Level of DHL, Immunophenotype. RESULTS: In the first study (113 patients), the following variables had a worse influence on survival: yellow race (P<0.1); ECOG II, III e IV (P<0.1) and extranodal disease (P<0.1) for high grade lymphomas; constitutional symptoms (P<0.1), ECOG II, III e IV (P<0.1) and involvement of CNS (P<0.1) for intermediate grade and the subtype lymphoplasmocytoid (P=0.0186) for low grade lymphomas. In the second survey (93 patients), when treatment was included, the variables related to NHL survival were: CNS involvement (P<0.1) for high grade lymphomas, constitutional symptoms (P<0.1), ECOG II, III, IV (P=0.0185) and also CNS involvement (P<0.1) for the intermediate group. There were no variables related to the survival for low-grade lymphomas. CONCLUSIONS: The intermediate grade lymphomas were more compatible with data found in the literature, probably because of the larger number of patients. In this specific case, the treatment did not have an influence on the survival.

Female↗
PubMed2000

Genotoxicity of instant coffee and of some phenolic compounds present in coffee upon nitrosation.

Instant coffee exhibits genotoxic activity upon nitrosation at acidic pH values in the Ames tester strain TA100. Using adsorption chromatography (Amberlit XAD-2) it was observed that the major fraction of molecules responsible for the genotoxic activity upon nitrosation was not retained on this resin, suggesting that the polar molecules present in instant coffee could be responsible for the genotoxicity observed upon nitrosation. Some phenolic molecules present in instant coffee (catechol, caffeic acid, and chlorogenic acid) were also genotoxic upon nitrosation under the same experimental conditions. The concentrations of nitrosatable phenolic compounds in the studied coffee were determined by HPLC and their contributions to the total genotoxicity observed were studied. The results obtained suggest that besides phenolic compounds other molecules were also involved in the genotoxicity of this beverage upon nitrosation. Teratogenesis Carcinog. Mutagen. 20:241-249, 2000.

Adsorption↗
PubMed2000

A sensitive method for assaying chemotaxic responses of Leishmania promastigotes.

This article describes a sensitive, cheap, and easy method for assaying chemotaxic responses of Leishmania promastigotes. A gradient of the substance to be assayed was produced inside a series of commercially available capillary tubes submerged in a promastigote suspension. After an incubation period, the attractiveness of the substance under test was measured by counting the number of parasites in the capillaries in a Neubauer chamber. Different responses were detected in two strains of Leishmania amazonensis and one strain of L. chagasi after standardization of the method to assay attraction to carbohydrates. Very different responses were obtained when the test was performed using promastigotes of the same strain in two different physiological states (log and stationary phase). The stationary phase cells showed an enhanced chemotaxic capability, which can be explained by the fact that the metacyclic forms commonest in stationary phase cultures have greater mobility than other promastigotes. This method will permit studies to be made of the attractive response to different substances in Leishmania species and other trypanosomatids and facilitate characterization of the potential receptors involved in the chemotaxic response. An adaptation of the method to assay the response to repellent substances is also provided.

Animals↗
PubMed2000

Post-transplant lymphoproliferative disorders (PTLD) after renal transplantation: management and evolution of seven cases among 1002 renal transplants in São Paulo, Brazil.

We reported seven cases (0.7%) of PTLD among 1002 renal transplants performed at Renal Transplant Service from Hospital São Paulo-Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil, between 1976 and 1997. There were three male and four female patients with median age of 37 year-old. According to Ann Arbor staging system there were four localized extra-nodal intermediate-grade NHL, one disseminated low-grade NHL and two polyclonal lymphoid hyperplasia. Four patients received cadaveric, two received related and one received unrelated renal transplant. PTLD occurred after a median latency period of 36 months (ranging from 5 to 84 months). In situ hybridization for EBER1 was performed in five patients and molecular evidence of EBV was found in 3 cases (two DLCL and one lymphoplasmocytoid lymphoma). All patients were treated with immunosuppression withdrawal, four patients received anthracyclin-based chemotherapy for control of localized or systemic clonal disease and three were treated with resection of primary PTLD. Four of seven patients (57%) are in complete remission 11, 20, 25 and 79 months after PTLD onset. One patient lost follow-up and two patients died due to lymphoma relapse, respectively 4 and 10 months after completion of treatment. In conclusion, our experience with this small group of patients showed that: 1) immunosuppression withdrawal is not necessarily associated with loss of renal transplant and can be used as the only treatment for polyclonal PTLD; 2) chemotherapy can simultaneously lead to clonal PTLD remission and periodic immunosuppression, avoiding graft rejection after immunosuppression withdrawal.

Adult↗
PubMed1999

Clinical management of six cases of low-risk primary tonsillar non-Hodgkin's lymphoma.

CONTEXT: There have been many reports that favor aggressive systemic treatment with chemotherapy and radiotherapy, even for well-localized lymphomas, avoiding the need for tonsillectomy of the normal tonsil. CASE REPORT: We report six cases of primary tonsillar lymphoma with a median patient age of 42 years. There were two lymphoma cases with diffuse large cells, two cases with mixed small and large cells, one with small cells and one indeterminate. They were treated with six cycles of chemotherapy and cervical radiotherapy. All patients achieved durable complete remission. Our data agree with previous reports that suggested that primary tonsillar high-grade B-cell NHL has a good prognosis if aggressively treated.

Adult↗
PubMed1999

Genotoxicity of instant coffee: possible involvement of phenolic compounds.

Instant coffee exhibits direct genotoxic activity in the tester strains TA 98, 100, 102, 104 and YG 1024. In the Ames tester strain TA 100, the presence of S9 mix, S100 mix, S9 mix without cofactors led to a significant decrease of the genotoxicity observed. The decrease observed in the presence of S9 mix seems to be highly correlated with the catalase content of S9 mix. The genotoxicity of instant coffee detected in strain TA 100 was dependent on the pH, with higher genotoxic effects at pH values above neutrality. Also, dependent on the pH was the ability of some phenolic molecules present in coffee promoting the degradation of deoxyribose in the presence of Fe3+/EDTA. These results suggest that apart from other molecules present in instant coffee responsible for their genotoxicity in several short term assays, phenolic molecules could also be implicated in the genotoxicity of coffee, via reactive oxygen species arising from its auto-oxidation.

Animals↗
PubMed1999

Nephrotic syndrome as a clinical manifestation of graft-versus-host disease (GVHD) in a marrow transplant recipient after cyclosporine withdrawal.

GVHD is one of the most frequent complications of BMT and recently nephrotic syndrome (NS) has been described as a manifestation of chronic GVHD. Here, we present an AA patient who developed NS 1 year after BMT when cyclosporine was stopped. Renal biopsy showed focal sclerosis associated with membranous deposits. He also had other clinical manifestations of chronic GVHD: sicca-like syndrome and colestasis. After 15 days of CsA therapy, he experienced a remarkable improvement in the NS and GVHD as a whole. We comment on immunological mechanisms that could be involved in the pathogenesis of this manifestation.

Adult↗
PubMed1998

HTLV-I infection among relatives of patients with adult T-cell leukemia/lymphoma in Brazil: analysis of infection transmission.

We examined the presence of HTLV-I infection among 66 family members of 13 patients with well documented ATL to investigate the routes of HLTV-I transmission in a Southeast region of Brazil. HTLV-I infection was screened by an enzyme immunossay (ELISA) test and all repeatedly positive or indeterminate ELISA samples were further tested by a Western-Blot (WB) technique. Indeterminate and inconclusive WB samples were confirmed by a polymerase chain reaction (PCR). ELISA results showed that 40 (60.6%) individuals were not infected; 16 (24.2%) were positive; and 10 (15.2%) were undetermined. Among 16 ELISA positive subjects, 14 (87.5%) were confirmed to be positive by WB while 2 (12.5%) showed inconclusive results. Based on the laboratory data, questionnaire analysis, and family/epidemiological studies, we concluded that HTLV-I vertical transmission occurred in 6 of the 13 families. In 3 of these 6 families, the horizontal transmission also could be demonstrated. An isolated horizontal transmission was detected in one family, and in 6 families we did not find any infected family member. All HTLV-I-infected persons were clinically asymptomatic. The occurrence of an effective HTLV-I vertical transmission detected by the present study suggest that HTLV-I infection is endemic in the Southeast region of Brazil. Consistent with the modes of transmission, the HTLV-I antibody seroprevalence was greater in relatives of ATL patients than in the general blood donor Brazilian population (0.4%). In addition, the present data suggest that HTLV-I carries a high infectivity rate but a low virulence.

Adolescent↗
PubMed1996

The relationship between megacolon and carcinoma of the colon: an experimental approach.

'Carcinoma of the colon does not occur in cases of megacolon' is an axiom held by Brazilian physicians working in endemic areas for Chagas' disease. The objective of the present study was to test this axiom experimentally by submitting rats with experimental megacolon to a carcinogen which causes carcinoma of the colon. Eighty young male Wistar rats received serosal application of either saline (0.9% NaCl) or 2 mM benzalkonium chloride (BAC) to the distal colon. Ten months later randomly chosen saline and BAC rats were injected weekly with dimethylhydrazine (DMH) for 20 weeks. Non-DMH-treated rats from both original groups were maintained, for a total of four experimental groups. Three months after the injections all surviving rats were killed. At autopsy the presence of absence of carcinomas along the colon was recorded. The induction of megacolon was evaluated by morphometry of the wall from the distal colon and myenteric denervation was assessed by neuron counts. An increase of at least 2-fold in distal colon wall thickness confirmed the induction of megacolon in BAC-treated rats. Neuronal counts from BAC and control rats not treated with DMH showed an average denervation of 63%. The number of distal colon carcinomas in BAC+DMH-treated rats was significantly lower than that in DMH-treated rats. These findings appear to contradict the traditional concept of carcinogenesis of the colon. The clinical axiom was reproduced experimentally.

1,2-Dimethylhydrazine↗
PubMed1995

Experimental megaileum.

Typical megaileum occurred in young male Wistar rats three months after ileum myenteric plexus denervation. An average of 58.4% denervation of the Auerbach plexus was obtained by serosal application of benzalkonium chloride (0.2% v/v). Denervation was assessed by ganglion cell counts in an 8 nm ring-shaped histological sectfrom the midportion of the treated segment. A morphometric study showed that the increased thickness of the megaileum wall was due to muscle hypertrophy and mucosal hyperplasia. The potential usefulness of this model of megaileum is emphasized.

Animals↗
PubMed1995

Peripheral and coronary sinus catecholamine levels in patients with severe congestive heart failure due to Chagas' disease.

The aim of this study was to assess the peripheral and cardiac autonomic system by catecholamine measurements in patients with severe chagasic and nonchagasic heart failure. Fifteen chagasic and 16 nonchagasic patients were enrolled in the study. Plasma venous norepinephrine levels (pg/ml) were 397.26 +/- 250.11 for chagasic and 660.05 +/- 455.57 for nonchagasic patients (p > 0.05), plasma venous epinephrine levels 215.84 +/- 254.04 for chagasic and 106.17 +/- 65.90 for nonchagasic patients (p > 0.05), aortic root norepinephrine levels 435.46 +/- 306.60 for chagasic and 668.16 +/- 512.82 for nonchagasic patients (p > 0.05), aortic root epinephrine levels 300.33 +/- 302.69 for chagasic and 199.98 +/- 162.88 for nonchagasic patients (p > 0.05), coronary sinus norepinephrine levels 636.10 +/- 495.22 for chagasic and 552.17 +/- 535.54 for nonchagasic patients (p > 0.05) and coronary sinus epinephrine levels 226.66 +/- 277.47 for chagasic and 69.21 +/- 35.62 for nonchagasic patients (p = 0.02). Myocardial and peripheral norepinephrine and epinephrine extractions were similar for both groups. Taken together, these findings may suggest that chagasic patients with congestive heart failure have biochemical evidence of cardiac autonomic dysfunction with preservation of the peripheral sympathetic activity.

Adolescent↗