RESUMO
ABSTRACT A survey was conducted to estimate the frequency of Leptospira sp. infection in cattle in the State of Paraíba, Brazil. A random sample of 6 municipalities was chosen from each of 3 ecoregions of the state: the Agreste/Litoral, the Cariri/Curimatau and the Sertão. These 18 municipalities were broken down into quadrants and one property was selected at random from each quadrant. Random samples were collected from at least eight animals at each property, in four-age categories, summing at least 32 animals per property. All municipalities that were included in the study (100%) and 87.75% of the properties had at least one positive sample for one of the 15 different Leptospira sp. serovars (16 strains) studied. From 2,343 samples, 759 showed positive reaction to, at least, one of the 16 strains tested. Four hundred and seventy animals were positive to multiple strains. The serovar Hardjo, of the Sejroe serogroup, was the most frequent and accounted for 16.05% (95% CI 12.69% to 19.41%) of the positive results (376 positive reactions). There were differences in the frequency of positive results according to the two strains of serovar Hardjo used: strain Norma (15.62% 95% CI 12.38% to 18.86%), isolated in Brazil, and reference strain Hardjoprajitino (2.43% 95% CI 1.12% to 3.75%). The remaining serovars tested had frequencies lower than 2.8%. Results obtained in the present study confirmed that Leptospira interrogans serovar Hardjo is widely spread in the State of Paraíba, Brazil.
RESUMO Foi realizada a estimativa de freqüência de infecção por Leptospira sp. em bovinos do Estado da Paraíba, Brasil. Seis municípios foram escolhidos ao acaso em cada uma das 3 ecorregiões do Estado: Agreste/Litoral, Cariri/Curimatau e Sertão. Estes 18 municípios foram divididos em quadrantes e uma propriedade foi selecionada por quadrante. As amostras de sangue foram coletadas aleatoriamente de, pelo menos, 32 animais por propriedade. Todos os municípios incluídos no estudo (100%) e 87,75% das propriedades apresentaram no mínimo uma amostra positiva para pelo menos uma das 15 diferentes sorovariedades de Leptospira sp. (16 amostras) testadas. Dos 2.343 animais examinados, 759 reagiram positivamente para pelo menos uma das 16 amostras de Leptospira sp. testadas. Quatrocentos e setenta animais reagiram positivamente para múltiplas amostras. A sorovariedade Hardjo, do sorogrupo Sejroe, foi a mais freqüente com 16,05% (95% IC 12,69% a 19,41%) dos resultados positivos (376 reações positivas). Houve diferenças na freqüência dos resultados positivos para as amostras da sorovariedade Hardjo testadas: amostra Norma (15,62% 95% IC 12,38% a 18,86%), isolada no Brasil, e a amostra de referência Hardjoprajitino (2,43% 95% IC 1,12% a 3,75%). As demais sorovariedades apresentaram freqüências inferiores a 2,8%. Os resultados obtidos no presente estudo confirmam que Leptospira interrogans serovar Hardjo é amplamente distribuída no Estado da Paraíba, Brasil.
RESUMO
Numerous studies have established that stimulation of cell growth by members of the fibroblast growth factor (FGF) family of polypeptides is dependent upon an extracellular pathway. Acidic FGF (FGF-1), however, lacks a classical signal sequence for secretion, thereby making it difficult to evaluate regulation of biological activity by this growth factor. Efforts in this laboratory have utilized molecular techniques of retrovirology and transgenic modeling to introduce cDNA sequences encoding either an intracellular or extracellular form of FGF-1 into primary diploid cells to examine trafficking and compartmentalization of FGF-1. Several lines of evidence obtained from these models provide a compelling argument that the stimulation of FGF-1-associated cellular transformation is restricted to an extracellular, receptor-mediated pathway, involving protein tyrosine phosphorylation and nuclear localization. In addition, an unconventional secretion pathway for intracellular FGF-1 has been identified that involves mechanisms associated with oxidative stress.
Assuntos
Fator 1 de Crescimento de Fibroblastos/fisiologia , Neovascularização Fisiológica/efeitos dos fármacos , Transdução de Sinais/fisiologia , Animais , Diploide , Fator 1 de Crescimento de Fibroblastos/química , Regulação da Expressão Gênica , Vetores Genéticos , Camundongos , Camundongos Transgênicos , Modelos Genéticos , Fosforilação , Receptores de Fatores de Crescimento de Fibroblastos/fisiologia , Tirosina/metabolismoRESUMO
Numerous studies have established that stimulation of cell growth by members of the fibroblast growth factor (FGF) family of polypeptides is dependent upon an extracellular pathway. Acidic FGF (FGF-1), however, lacks a classical signal sequence for secretion, thereby making it difficult to evaluate regulation of biological activity by this growth factor. Efforts in this laboratory have utilized molecular techniques of retrovirology and transgenic modeling to introduce cDNA sequences encoding either an intracellular or extracellular form of FGF-1 into primary diploid cells to examine trafficking and compartmentalization of FGF-1. Several lines of evidence obtained from these models provide a compelling argument that the stimulation of FGF-1-associated cellular transformation is restricted to an extracellular, receptor-mediated pathway, involving protein tyrosine phosphorylation and nuclear localization. In addition, an unconventional secretion pathway for intracellular FGF-1 has been identified that involves mechanisms associated with oxidative stress
Assuntos
Animais , Camundongos , Fator 1 de Crescimento de Fibroblastos/fisiologia , Neovascularização Fisiológica/efeitos dos fármacos , Transdução de Sinais/fisiologia , Diploide , Fator 1 de Crescimento de Fibroblastos/química , Regulação da Expressão Gênica , Vetores Genéticos , Camundongos Transgênicos , Modelos Genéticos , Fosforilação , Receptores de Fatores de Crescimento de Fibroblastos/fisiologia , Tirosina/metabolismoRESUMO
Peroxynitrite is a powerful oxidant formed by the near-diffusion-limited reaction of nitric oxide with superoxide. Large doses of peroxynitrite (> 2 mM) resulted in rapid cell swelling and necrosis of undifferentiated PC12 cells. However, brief exposure to lower concentrations of peroxynitrite (EC50 = 850 microM) intially (3-4 h) caused minimal damage to low-density cultures. By 8 h, cytoplasmic shrinkage with nuclear condensation and fragmentation became increasingly evident. After 24 h, 36% of peroxynitrite-treated cells demonstrated these features associated with apoptosis. In addition, 46% of peroxynitrite-treated cells demonstrated DNA fragmentation (by terminal-deoxynucleotide transferase-mediated dUTP-digoxigenin nick end-labeling) after 7 h, which was inhibited by posttreatment with the endonuclease inhibitor aurintricarboxylic acid. Serum starvation also resulted in apoptosis in control cells (23%), the percentage of which was not altered significantly by peroxynitrite treatment. Although peroxynitrite is known to be toxic to cells, the present study provides a first indication that peroxynitrite induces apoptosis. Furthermore, pretreatment of cells with nerve growth factor or insulin, but not epidermal growth factor, was protective against peroxynitrite-induced apoptosis. However, both acidic and basic fibroblast growth factors greatly increased peroxynitrite-initiated apoptosis, to 63 and 70%, respectively. Thus, specific trophic factors demonstrate differential regulation of peroxynitrite-induced apoptosis in vitro.