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D F Chamone

Publications and source records attributed to D F Chamone.

At least 19 recordsLinked to original sources
PubMed2002

Prevalence of GB virus C (hepatitis G virus) and risk factors for infection in São Paulo, Brazil.

The prevalence of GB virus C (GBV-C) varies widely throughout the world. A cross-sectional study was conducted in the city of São Paulo, Brazil, to estimate the prevalence of GBV-C infection and to identify associated risk factors, using a large sampling of the general population rather than blood donors or an illness-related group of subjects. GBV-C RNA was detected by reverse-transcriptase polymerase chain reaction using primers directed to the 5' noncoding region (NCR) and nonstructural 5A region (NS5A) in serum samples from 1,039 healthy individuals 2 years of age or more. Fifty-two individuals were positive for both sets of primers and one was positive for NS5A only (prevalence of GBV-C infection, 5.1%; 95%CI, 3.9-6.7%). No child under 5 years of age was found positive. Among subjects aged 5 years or more, the prevalence of infection increased consistently with age, up to 30-39 years (8.3%), and decreased from then on. The number of sexual partners in the last 3 years (2 or more: OR, 2.6; 95%CI, 1.3-5.5) and history of contact with blood-sucking insects (OR, 2.5; 95%CI 1.2-5.4) were independently associated with GBV-C infection. In conclusion, the prevalence of GBV-C infection is high in São Paulo. In addition to parenteral transmission, another route, e.g. sexual or vertical, may be involved.

Adolescent↗
PubMed2000

Serological confirmation of Chagas' disease by a recombinant and peptide antigen line immunoassay: INNO-LIA chagas.

Although screening for Trypanosoma cruzi antibodies is mandatory in most South American countries, current tests are insensitive and have poor specificity. A recently optimized line immunoassay (the INNO-LIA Chagas assay) for the serological confirmation of Chagas' disease was evaluated at a large blood bank in São Paulo, Brazil. Sera from blood donors who reacted in at least one of three serological screening assays (n = 1,604) and who returned for a follow-up were retested, and the donors were interviewed to assess their epidemiological risk. The results obtained by the confirmatory assay evaluated in this study were compared to those obtained by the three different screening assays. Upon consideration of the consensus results obtained by the three different screening assays as a "gold standard," the INNO-LIA Chagas assay showed a sensitivity of 99.4% (95% confidence interval [CI], 98.3 to 99.9) and a specificity of 98.1% (95% CI, 96.6 to 99.0) for positive (n = 503) and negative (n = 577) sera. The INNO-LIA Chagas assay confirmed the results for significantly larger numbers of positive samples of at-risk individuals independent of the number of positive screening tests (P = 0.017, Mantel-Haenszel test). In conclusion, the INNO-LIA Chagas assay reliably confirmed the presence of antibodies to T. cruzi and can be implemented as a confirmatory assay for Chagas' disease serology.

Animals↗
PubMed1999

An improved, PCR-based strategy for the detection of Trypanosoma cruzi in human blood samples.

Attempts were made to improve the PCR-based detection of Trypanosoma cruzi in blood samples, primarily for screening blood donors. Samples were obtained from candidate donors who were reactive in one or two of three serological tests for Chagas disease (and therefore considered 'indeterminate') or in all three tests (3+). Each sample was then examined using three different, PCR-based techniques: 'PCR-I' (in which the target DNA is a nuclear repetitive sequence); 'PCR-II' [amplifying a conserved region of the T. cruzi kinetoplast DNA (kDNA)]; and 'PCR-III' (a new strategy in which the target kDNA is amplified by 'nested' PCR). Among the samples from 3+ individuals, PCR-I, PCR-II and PCR-III amplified two (3.8%) out of 52, four (4.5%) out of 88, and 27 (25.7%) out of 105 samples tested, respectively. Seven, 69 and 70 samples from 'indeterminate' subjects were tested by PCR-I, PCR-II and PCR-III, respectively; there was not a single positive result by PCR-I or PCR-II, but three (4.3%) of the samples tested by PCR-III were positive. In a reconstruction experiment, in conditions in which PCR-I and PCR-II could not detect 10,000 parasites/ml, PCR-III was able to detect one parasite/ml. Although all three PCR-based strategies examined had rather poor sensitivities, PCR-III was far more sensitive than PCR-I or PCR-II.

Animals↗
PubMed1998

Evaluation of the performance of Brazilian blood banks in testing for Chagas' disease.

BACKGROUND AND OBJECTIVES: Due to the low sensitivity and reproducibility of available tests, in 1989 it became mandatory for all Brazilian blood donors to be screened for Chagas' disease by at least two serological techniques. In 1994 the Brazilian Ministry of health launched a program to systematically evaluate the quality of serological screening for the detection of blood-transmissible diseases as performed by public blood banks. METHODS: A blind panel containing positive samples for blood-transmissible disease was distributed to 57 major public blood banks in four sequential programs. RESULTS: The ELISA test was chosen by the majority of the blood banks. There were 64 (3.7%) false-negative results, 49 produced by banks using indirect hemagglutination. Since most blood banks screened with more than one test for Chagas, only 8 samples were actually missed, of which 3 were by banks using only one test. CONCLUSION: Our data show a clear improvement in performance of Brazilian blood banks testing for Chagas' disease.

Animals↗
PubMed1997

Clinical features and successful recovery from disseminated nocardiosis after BMT.

Nocardiosis has rarely been described after BMT. When the doses of immunosuppressive therapy were tapered, a 46-year-old BMT recipient developed chronic graft-versus-host disease (GVHD) and immunosuppresive drugs were increased. Sixteen days later the patient developed nocardiosis diagnosed by lung biopsy. Trimethoprim/sulfamethoxazole (TMP/SMZ) was initiated but the doses were reduced because of rising creatinine levels. Skin and cerebral dissemination of nocardiosis was observed and TMP/SMZ doses were increased. After 4 months, the brain lesion was unaltered despite resolution of pulmonary lesions. Clinical improvement was observed after drainage of the brain abscess.

Anti-Bacterial Agents↗
PubMed1997

Human T cell lymphotropic virus type-1-associated myelopathy/tropical spastic paraparesis in Sao Paulo, Brazil: association with blood transfusion.

Human T cell lymphotropic virus type-1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP) has been epidemiologically linked to prior blood transfusion. The prevalence of transfusion as a risk factor for infection varies among endemic areas. Here we report the relative frequency of reported history of blood transfusion among 52 patients evaluated in Sao Paulo, Brazil. A patient reported history of blood transfusion prior to the onset of symptoms, found in 15 (28.8%) of the patients, was the most important risk factor identified in this group of patients when compared with a history of sexually transmitted diseases, homo/bisexuality, sexual promiscuity (three or more sexual partners a year), and intravenous drug use. The mean time between reported transfusions and the onset of symptoms was longer than previously reported. There was no trend toward a more severe evolution to motor inability among the HAM/TSP patients with a history of previous transfusion.

Adult↗
PubMed1995

Human T lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis in São Paulo, Brazil.

We conducted a prospective clinical and epidemiologic evaluation of 45 cases of human T lymphotropic virus type I (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in São Paulo, Brazil. All enrolled patients had progressive chronic myelopathy and high titers of HTLV-I and HTLV-II antibodies, as determined by enzyme immunoassay and western blot. In 24 cases, the polymerase chain reaction (PCR) was performed so that HTLV-I could be distinguished from HLTV-II. The clinical and epidemiologic features of the patients from our study were similar to those of patients with HAM/TSP from other areas of endemicity for HTLV-I except that more patients in our study had received a blood transfusion prior to their illness. Despite the presence of HTLV-II virus in Brazil, all patients whose serum was tested by PCR were found to be infected with the HTLV-I virus.

Adult↗
PubMed1995

Quantitative expression of proliferating cell nuclear antigen by western blot (PCNAWB) in peripheral blasts correlates with remission induction in patients with acute myelogenous leukemia.

Proliferating cell nuclear antigen (PCNA) is a 36-kD nuclear protein that functions as a cofactor of delta DNA polymerase which is regulated in a cell cycle-dependent fashion. PCNA expression also increases when cells are actively engaged in DNA repair. We used Western blotting (WB) to measure the level of expression of PCNA in peripheral blasts of 36 adult acute myelogenous leukemia (AML) patients treated with Ara-C based induction regimens. PCNA levels correlated positively with the percentage of cells in S+G2M of the cell cycle. Logistic regression analysis revealed PCNA (beta = 4.5162; p = 0.0260) together with age (beta = 0.1777; p = 0.0364) as independent variables for remission induction: high PCNA levels were associated with poor response to induction therapy. PCNA expression was not, however, a predictor of survival in this subset of patients. We conclude that PCNA levels in this disease may be important for predicting response to Ara-C based remission induction chemotherapy.

Adult↗
PubMed1993

Chagas' disease diagnosis: evaluation of several tests in blood bank screening.

Blood transfusion is one of the principal routes of transmission of Chagas' disease, a major endemic disease in Latin America. Methods for blood screening are not accurate and may yield false results that lead to high social and economic costs. This study compares two methods of diagnosing Chagas' disease (indirect immunofluorescence and hemagglutination) and several enzyme-linked immunosorbent assays (ELISAs) with regard to specificity and sensitivity, by using human sera with known serologic and parasitologic characteristics, as well as samples with discrepant results on conventional serologic tests. An ELISA using recombinant antigens showed no cross-reactivity with sera that were positive for other diseases. All evaluated ELISAs performed well, and their use may lead to a reduction of more than 50 percent in the number of discordant sera. Further improvements are needed in view of the complexity of the serologic diagnosis of Chagas' disease.

Antigens, Protozoan↗
PubMed1993

Circulating platelet aggregates indicative of in vivo platelet activation in pulmonary hypertension.

The authors investigated the existence of circulating cellular aggregates in 12 patients with moderate to severe pulmonary hypertension, using scanning electron microscopy. Peripheral venous blood was collected in the presence of 11.5 mM buffered ethylenediaminetetraacetic acid, in order to disperse freshly formed disaggregable aggregates. Irreversible aggregates represented by platelet clusters and/or platelet attachment to either leukocytes or red cells were identified in 7 patients with pulmonary hypertension. Endogenous platelet activation was further confirmed by a significant increase in plasma levels of beta-thromboglobulin in comparison with controls (33.8 +/- 14.1 vs 22.7 +/- 11.5 ng/mL respectively, p < 0.025). The presence of irreversible aggregates in the blood stream strongly suggests that cell-cell interactions actually occur in vivo in these patients. If so, therapeutic measures aimed at preventing in situ thrombosis and its consequences may be beneficial in this disorder.

Adolescent↗
PubMed1993

Proliferating cell nuclear antigen (PCNA) expression in chronic lymphocytic leukemia (CLL).

Chronic Lymphocytic Leukemia (CLL) is usually an indolent disorder which in some patients assumes an aggressive clinical course. In order to assess at presentation the prognosis of a given patient, several staging systems and prognostic variables have been proposed including the expression of the Proliferating Cell Nuclear Antigen (PCNA). PCNA is a 36 kd nuclear protein, the regulation of which is cell cycle-dependent. In CLL, PCNA levels correlate with cell proliferation, clinical stage and the lymphocyte doubling time (LDT). Furthermore, preliminary data suggests that PCNA expression may also predict response to Fludarabine-based chemotherapy. Since PCNA is a cofactor for Delta DNA polymerase, PCNA overexpression in CLL may also reflect the intrinsic DNA repair activity of the leukemic cells and thus their resistance to chemotherapy. Further studies aiming at modulation of PCNA expression in CLL cells may clarify this issue and may offer a future new therapeutic strategy with which to treat this disorder.

Antigens, Neoplasm↗
PubMed1991

Coronary recanalization rate after intravenous bolus of alteplase in acute myocardial infarction.

The demonstration in animals that recombinant tissue-type plasminogen activator produces prolonged thrombolysis after its clearance from the circulation has prompted a few pilot studies of bolus administration in patients. Alteplase (bolus dose of 70 mg) resulted in the highest recanalization rate in our previous pilot study comparing bolus doses of 50, 60 and 70 mg of alteplase in patients with acute myocardial infarction. The aim of the present trial was to assess the efficacy and safety of the same bolus dose in a larger number of patients. A further objective was to study the angiographic reocclusion rate at 12 to 24 hours in patients who had a recanalized infarct-related coronary artery at 90 minutes and were randomized at that time to a bolus dose or an infusion for 3 hours of 30 mg of alteplase. Sixty patients with acute myocardial infarction and angiographically documented total occlusion of the infarct-related coronary artery before thrombolysis were treated within 5 hours of onset of symptoms with an intravenous 70-mg bolus dose of alteplase (or 80 mg if body weight was greater than or equal to 90 kg). Each patient received 5,000 IU of heparin intraarterially and 100 mg of aspirin by mouth before administration of alteplase. Coronary angiography was repeated 60 and 90 minutes after alteplase administration. The recanalization rate of the infarct-related coronary artery was 55% (95% confidence interval, 43 to 66%) at 60 minutes and 48% (95% confidence interval, 37 to 60%) at 90 minutes. Pretreatment levels of lipoprotein (a) were not significantly related to recanalization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Effect of ticlopidine and dipyridamole on platelet aggregation and count in patients with chronic stable angina pectoris].

PURPOSE: To compare the ticlopidine and dipyridamole effects on platelets count and aggregation in patients with stable coronary artery disease. PATIENTS AND METHODS: Eighty patients with stable coronary artery disease and mean of 58.3 +/- 5.8 years were studied. They were divided into two equal groups of 40 patients and each one treated with ticlopidine or dipyridamole. Platelets count and aggregation were examined before treatment and at first and fourth weeks of treatment. RESULTS: At the end of fourth week of treatment, spontaneous, induced by ADP or by adrenalin platelet aggregation inhibition was observed, respectively, in 82.5%, 72.5% e 67.5% of the patients in ticlopidine group. The spontaneous, induced by ADP or by adrenalin, platelet aggregation inhibition in the patients of dipyridamole group was, respectively, 40%, 30% e 27.5% (p less than 0.001). The platelets count did not change in both groups. CONCLUSION: The ticlopidine effect is much more evident in platelet aggregation inhibition than dipyridamole, and maybe a choice in the prevention of cardiovascular events.

Coronary Disease↗
PubMed1989

Bolus alteplase.

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Clinical Trials as Topic↗
PubMed1989

Determination of the putative binding site for fibronectin on platelet glycoprotein IIb-IIIa complex through a hydropathic complementarity approach.

We have applied the principle of complementary hydropathy to the prediction of the binding site for fibronectin (FN) and for the alpha-chain of fibrinogen in the platelet receptor complex glycoprotein (GP) IIb-IIIa. Since both ligands bind to it through their respective RGDS (Arg-Gly-Asp-Ser) domains and since both have been cloned, we were able to deduce the amino acid sequence of the binding site from the nucleotide sequence coding for RGDS in both proteins. The deduced peptides were very similar. Antibodies raised against a synthetic peptide WTVPTA (Trp-Thr-Val-Pro-Thr-Ala) deduced from the cloned rat FN RGDS domain block ADP-mediated platelet aggregation; this block can be overcome by additional fibrinogen. In Western blots of whole cell platelet extracts run under reducing conditions, this antibody binds to a 108-kDa band. It also binds to affinity-purified GP IIIa. Furthermore, it reacts strongly with GP IIIa immunoprecipitated by a commercially available anti-GP IIb-IIIa monoclonal antibody. Binding of affinity-purified GP IIb-IIIa complex to fibronectin is inhibited by the 110-kDa FN fragment. Similar inhibitions can be effected by WTVPTA (Trp-Thr-Val-Pro-Thr-Ala) and GAVSTA (Gly-Ala-Val-Ser-Thr-Ala) predicted from the rat and human fibronectin nucleotide sequences, respectively. GAGSTA (Gly-Ala-Gly-Ser-Thr-Ala) and GARSTA (Gly-Ala-Arg-Ser-Thr-Ala) related to the human peptide but with discrepant hydropathies are noninhibitory.

Adult↗