RESUMO
In the Amazon and Orinoco basins, mercury has been released from artisanal and industrial gold mining since the Colonial time, as well as a result of deforestation and burning of primary forest, that release natural deposits of methyl mercury, affecting the local aquatic vertebrate fauna. This study reports the presence of mercury in river dolphins' genera Inia and Sotalia. Mercury concentrations were analysed in muscle tissue samples collected from 46 individuals at the Arauca and Orinoco Rivers (Colombia), the Amazon River (Colombia), a tributary of the Itenez River (Bolivia) and from the Tapajos River (Brazil). Ranges of total mercury (Hg) concentration in muscle tissue of the four different taxa sampled were: I. geoffrensis humboldtiana 0.003-3.99 mg kg-1 ww (n = 21, Me = 0.4), I. g. geoffrensis 0.1-2.6 mg kg-1 ww (n = 15, Me = 0.55), I. boliviensis 0.03-0.4 mg kg-1 ww (n = 8, Me = 0.1) and S. fluviatilis 0.1-0.87 mg kg-1 ww (n = 2, Me = 0.5). The highest Hg concentration in our study was obtained at the Orinoco basin, recorded from a juvenile male of I. g. humboldtiana (3.99 mg kg-1 ww). At the Amazon basin, higher concentrations of mercury were recorded in the Tapajos River (Brazil) from an adult male of I. g. geoffrensis (2.6 mg kg-1 ww) and the Amazon River from an adult female of S. fluviatilis (0.87 mg kg-1 ww). Our data support the presence of total Hg in river dolphins distributed across the evaluated basins, evidencing the role of these cetaceans as sentinel species and bioindicators of the presence of this heavy metal in natural aquatic environments.
Assuntos
Golfinhos , Monitoramento Ambiental/métodos , Mercúrio/análise , Mineração , Músculos/química , Rios/química , Poluentes Químicos da Água/análise , Animais , Brasil , Colômbia , Conservação dos Recursos Naturais , Biomarcadores AmbientaisRESUMO
A retrospective medical record review was completed for 264 consecutive newborns receiving phototherapy for hyperbilirubinemia to determine whether a "rebound" increase in total serum bilirubin (TSB) level occurs after termination of phototherapy. The difference between mean TSB levels at discontinuation of phototherapy and at rebound was calculated by paired t test. TSB levels at rebound were significantly lower than at discontinuation of phototherapy for infants weighing > 1800 g (positive and negative Coombs' test results). There were no statistically significant differences among infants in the smaller weight categories, regardless of Coombs' test results. Infants completing phototherapy for hyperbilirubinemia who are otherwise healthy do not require follow-up solely to identify a rebound bilirubin level.
Assuntos
Bilirrubina/sangue , Icterícia Neonatal/terapia , Fototerapia , Peso ao Nascer , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Icterícia Neonatal/sangue , Masculino , Recidiva , Estudos RetrospectivosRESUMO
To describe the clinical spectrum of interstitial lung disease in children, we reviewed our experience with 48 patients during a 12-year period. Most patients initially had typical findings of restrictive lung disease and hypoxemia. Growth failure or pulmonary hypertension or both were found in more than one third. Specific diagnosis, made in 35 patients (70%), most often required invasive studies, particularly open lung biopsy. Although the diagnostic yield from open lung biopsy was high, the diagnosis of many patients remained uncertain. Many different disorders were encountered. The response to corticosteroids, bronchodilators, and chloroquine was inconsistent. Six patients died, five within 1 year after the initial evaluation. The spectrum of pediatric interstitial lung disease includes a large, heterogeneous group of rare disorders associated with high morbidity and mortality rates.
Assuntos
Fibrose Pulmonar/diagnóstico , Adolescente , Biópsia , Criança , Pré-Escolar , Doença Crônica , Colorado/epidemiologia , Seguimentos , Humanos , Lactente , Pulmão/diagnóstico por imagem , Pulmão/patologia , Prevalência , Fibrose Pulmonar/epidemiologia , Fibrose Pulmonar/terapia , Radiografia , Testes de Função Respiratória , Estudos Retrospectivos , Resultado do TratamentoRESUMO
The inhibition of xanthine oxidase by its reaction product, uric acid, was studied by steady state kinetic analysis. Uric acid behaved as an uncompetitive inhibitor of xanthine oxidase with respect to the reducing substrate, xanthine. Under 50 microM xanthine and 210 microM oxygen, the apparent K(i) for uric acid was 70 microM. Uric acid-mediated xanthine oxidase inhibition also caused an increase in the percentage of univalent reoxidation of the enzyme (superoxide radical production). Steady-state rate equations derived by the King-Altman method support the formation of an abortive-inhibitory enzyme-uric acid complex (dead-end product inhibition). Alternatively, inhibition could also depend on the reversibility of the classical ping-pong mechanism present in xanthine oxidase-catalyzed reactions.
Assuntos
Superóxidos/metabolismo , Ácido Úrico/farmacologia , Xantina Oxidase/antagonistas & inibidores , Radicais Livres , Cinética , Oxirredução , Oxigênio/farmacologia , Xantina , Xantinas/farmacologiaRESUMO
Recent reports have indicated the possibility that HIV-2 has been introduced into groups at risk for AIDS in Brazil. We studied sera collected in 1987 and 1988 from 1,821 at-risk individuals from diverse regions in Brazil. Of the 1,821 sera, 367 (20%) were confirmed as being positive for HIV-1 antibodies by enzyme-linked immunosorbent assay (ELISA), immunofluorescence (IF), and Western blot. An additional 33 (2%) sera displayed some reactivity to HIV-2-infected cells by IF. All 33 sera were subsequently tested in HIV-1 and HIV-2 Western blots as well as an ELISA using HIV-1- or HIV-2-specific peptides. All sera were confirmed as positive for HIV-1 and negative for HIV-2 antibodies in both assays. We conclude that caution should be used in the interpretation of serologic cross-reactivity between HIV-1 and HIV-2 and that there is no evidence that HIV-2 has entered groups at risk for HIV infection in Brazil.
Assuntos
Anticorpos Anti-HIV/sangue , Infecções por HIV/epidemiologia , Soroprevalência de HIV , HIV-2/imunologia , Western Blotting , Brasil/epidemiologia , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , HIV-1/imunologia , Humanos , Fatores de RiscoRESUMO
Chronic cough in childhood has many possible causes. The two most common are asthma and viral upper respiratory infection. Although usually associated with wheezing, dyspnea, or both, cough may be the sole manifestation of asthma ("cough-variant asthma"). Most important to initial evaluation are physical examination, patient history, and chest radiograph. Bronchial provocation testing may also prove helpful but is usually unnecessary. A trial of antiasthma therapy is appropriate when the pattern of symptoms is typical of asthma (excepting the lack of wheezing) and when nothing incompatible with asthma is present in the clinical picture. Drug therapy for cough-variant asthma is the same as that for more typical asthma. A vigorous trial of antiasthma therapy should not be considered complete unless a short course of high oral doses of corticosteroids has been included. The presence of clinical signs or symptoms atypical or incompatible with asthma and the failure of symptoms to respond to aggressive antiasthma therapy both warrant a more aggressive and complete diagnostic study.
Assuntos
Tosse/etiologia , Algoritmos , Asma/complicações , Criança , Pré-Escolar , Doença Crônica , Tosse/tratamento farmacológico , HumanosRESUMO
An extract from the pathogenic actinomycete Nocardia brasiliensis was mitogenic for murine lymphocytes. This deoxyribonucleic acid-synthetic response of whole spleen cells peaked after 48 h in culture at concentrations of Nocardia extract ranging from 10 to 200 micrograms/ml. The extract appeared to be a mitogen for B lymphocytes since cultures of spleen cells from congenitally athymic nude (nu/nu) mice and of antithymocyte serum plus complement-treated spleen cells from conventional (+/+) mice responded as well as untreated spleen cells from normal +/+ mice. Furthermore, thymocytes did not respond mitogenically to the extract. Mitogenic responses were stimulated in spleen cells from H-2(a), H-2(b), H-2(d), and H-2(k) mice, including lipopolysaccharide-nonresponder C3H/HeJ mice. This Nocardia extract also stimulated polyclonal B-cell activation to the hapten trinitrophenyl, serum protein human gamma globulin, and several mammalian erythrocytes in cultures of cells from both euthymic and nude mice. Additionally, the requirement for helper T cells in the primary in vitro immune response to sheep erythrocytes could be circumvented by the addition of this Nocardia extract. These results indicate that an extract from the pathogen N. brasiliensis can nonspecifically activate murine B lymphocytes and raise the possibility that polyclonal activation of B lymphocytes may contribute to the pathogenesis of nocardiosis.