RESUMO
BACKGROUND: The knowledge of the genic structure of a population is of great importance for evolutive studies. AIM: To estimate in a Chilean population sample from the low-middle and low socioeconomic strata of Santiago, haplotypes and allele frequencies for Gm and Km loci. SUBJECTS AND METHODS: The sample included 460 controls of a case-control study of typhoid fever. RESULTS: The G1m-G2m-G3m most frequent haplotypes were: za;..;g or 1,17;(-);21 = 0.4493;fn;b or 3;23;5,13 = 0.2522; f-,..;b or 3;(-);5,13 = 0.1389; zax;..;g or 1,2,17;(-);21 = 0.0685; za;..;b or 1,17;(-);5,13 = 0.0454; za;n;g or 1,17;23;21 = 0.0207; f;..;g or 3;(-);21 = 0.0129. The frequencies of Km alleles were 0.2391 and 0.7609 for Km1 and Km3 respectively. CONCLUSIONS: These frequencies are within those found in Amerindian and Caucasian populations as expected from the origin of the Chilean population. Gm haplotypes did not differ from Hardy-Weinberg equilibrium, while a significant lack of homozygous Km1/km1 was found in Km.
Assuntos
Alótipos de Imunoglobulina/genética , Alótipos Gm de Imunoglobulina/genética , Febre Tifoide/genética , Adolescente , Estudos de Casos e Controles , Criança , Pré-Escolar , Chile , Feminino , Frequência do Gene , Haplótipos , Humanos , Masculino , Fenótipo , População UrbanaRESUMO
The sample included 460 controls of a case control study of typhoid fever. The G1m-G2m-G3m most frequent haplotypes were: za,..;g or 1,17;(-);21=0.4493;fn;b or 3;23;5,13=0.2522;f-,..;b or 3;(-);5,13=0.1389; zax;..;g or 1,2,17;(-);21=0.0685;za;..;b or 1,17;(-);5,13=0.0454;za;n;g or 1,17;23;21=0.0207;f;..;g or 3;(-);21=0.0129. The frequencies of Km alleles were 0.2391 and 0.7609 for Km1 and km3 respectively. These frequencies are within those found in Amerindian and Caucasian populations as expected from the origin of the Chilean population. Gm haplotypes did not differ from Hardy-Weinberg equilibrium, while a significant lack of homozygous Km1/km1 was found in Km
Assuntos
Humanos , Masculino , Feminino , Adolescente , Febre Tifoide/genética , Haplótipos/genética , Alótipos Gm de Imunoglobulina/isolamento & purificação , Cadeias kappa de Imunoglobulina/genética , Estudos de Casos e ControlesRESUMO
Gm and Km allotypes of immunoglobulins were determined in children with typhoid fever (Cases), in children without infectious diseases (Con-1), and in children with fever but no Salmonella in their blood or bone marrow (Con-2). Children were sampled from the urban population of Santiago; and they belonged to the low and low-middle socioeconomic strata. Cases had a higher frequency of [f;(-);b1,b3 or 3;(-);5,13] G1m, G2m, G3m haplotype than Con-1 and Con-2. Con-1 and Con-2 did not differ in their Gm haplotype or Km allele frequencies, but they differed in phenotype distribution. Con-1 deviated from Hardy-Weinberg equilibrium for Km due to a lack of Km 1-1 homozygotes. The relationship among these results, the ethnic origin of Chileans, and the differential susceptibility to typhoid fever are discussed.
Assuntos
Alótipos de Imunoglobulina/genética , Alótipos Gm de Imunoglobulina/genética , Febre Tifoide/patologia , Adolescente , Análise de Variância , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Frequência do Gene/genética , Humanos , Alótipos de Imunoglobulina/sangue , Alótipos Gm de Imunoglobulina/sangue , Alótipos Gm de Imunoglobulina/classificação , Masculino , Fenótipo , Febre Tifoide/genética , Febre Tifoide/microbiologiaRESUMO
La prevalencia de fiebre tifoidea (FT) en nuestro país es alta, afectando principalmente a niños y adultos jóvenes. El número de informes en la literatura acerca de la asociación de FT y embarazo son escasos, no obstante, la mayoría de autores coinciden que la gestación no modifica la presentación clínica ni las alteraciones de laboratorio de las pacientes con FT. Por otra parte, se ha demostrado que la FT influye desfavorablemente en el curso del embarazo, asociándose a abortos y a partos pretémino. En el presente artículo se informa cinco casos de pacientes embarazadas complicadas con FT; una de ellas abortó, una presentó un parto pretérmino con la muerte neonatal de su producto y las tres restantes tuvieron un curso normal del embarazo, sin anormalidades en sus recién nacidos. La morbi-mortalidad tanto martena como fetal se encuentra en estrecha relación al tratamiento adecuado de esta infección. Durante la gestación está contraindicado el uso de cloranfenicol, pero tanto la ampicilina como ceftriaxona son opciones terapéuticas adecuadas para el tratamiento de la FT en esta etapa
Assuntos
Adulto , Humanos , Feminino , Aborto Espontâneo/etiologia , Aborto Séptico/patologia , Ampicilina/uso terapêutico , Antibacterianos/uso terapêutico , Ceftriaxona/uso terapêutico , Cloranfenicol , Idade Gestacional , Complicações Infecciosas na Gravidez/fisiopatologia , Complicações na Gravidez/fisiopatologia , Salmonella typhi/patogenicidade , Febre Tifoide/genéticaRESUMO
A case-control study on the association between genetic markers (ABO, Rh, MNSs and sex) and typhoid fever (TF) was performed. We found that (a) the B allele conferred protection to females for TF and a mild susceptibility to males; (b) the CDe haplotype (or the RH3 phenotype, mostly CDe/CDe) was associated with protection against Salmonella in both sexes, while cDE (or RH7, mostly cDE/cDE, and RH8, mostly cDE/cde) was associated with susceptibility to TF, and (c) heterozygotes Ss (MNSs system) had a high susceptibility, while SS and particularly ss homozygotes seemed to be protected for the disease. There were very significant interactions among the blood systems and sex.
Assuntos
Sistema ABO de Grupos Sanguíneos/genética , Sistema do Grupo Sanguíneo MNSs/genética , Sistema do Grupo Sanguíneo Rh-Hr/genética , Caracteres Sexuais , Febre Tifoide/genética , Estudos de Casos e Controles , Criança , Chile , Feminino , Marcadores Genéticos , Humanos , Masculino , Febre Tifoide/sangueRESUMO
El reconocimiento de heterogeneidad genética en pacientes com fiebre tifoidea permitiría estudios de importancia clínica y epidemiológica sobre el comportamiento de cohortes definidas ante esta infección. Con la hipótesis de que la respuesta en aglutininas (R. de Widal) es un fenotipo útil para este fin, se exploraron asociaciones entre el resultado de esta respuesta (positivo y negativo) al ingreso y parámetros clínicos y hematológicos, en 91 niños con fiebre tifoidea comprobada bacteriológicamente, hospitalizados en el Hosptial Roberto del Río durante el período 1981-82. Se encontró asociación ente el sexo y respuesta negativa de la R. de Widal en varones, cuando ésta fue hecha en la tercera semana de enfermedad (OR=10; p=0,052) y tendencia de las mujeres a expresar cifras por debajo del promedio para leucocitos totales en mayores de 10 años (OR - 2,43; p = 0,019), y para neutrófilos (%) en las menores de esta edad, cuando la R. de Widal fue negativa en estas últimas (OR = 10, p = 0,016). Estos hallazgos preliminares sugieren que la R. de Widal y el sexo podrían interactuar para determinar la presunta heterogeneidad en este grupo de niños
Assuntos
Criança , Humanos , Masculino , Feminino , Febre Tifoide/genética , Fatores Etários , Testes de Aglutinação , Fenótipo , Fatores Sexuais , Febre Tifoide/sangueRESUMO
Recognition of genetic heterogeneity in typhoid fever patients might allow studies on the behaviour of definite cohorts regarding this infection, which would be important for clinical and epidemiological purposes. Under the hypothesis that agglutinins response (Widal test) is a suitable phenotype for this objective, associations between results of this response at admission (positive and negative) and clinical and hematological variables were explored in 91 children with bacteriologically confirmed typhoid fever, admitted to a metropolitan hospital at Santiago, Chile, during 1981-82 period. Association between gender and negative Widal test was found in males when this test was performed during the third week of disease (OR = 10, p = 0.52) as well as a tendency of females to express figures below the mean for total WBC count in patients older than 10 years (OR = 2.43, p = 0.019) and for neutrophils (%) in younger than this age when the Widal test was negative in the latter (OR = 10, p = 0.016). These preliminary findings suggest that Widal test and gender might interact for determining the presumptive heterogeneity in this children group.
Assuntos
Testes de Aglutinação/métodos , Febre Tifoide/genética , Fatores Etários , Criança , Feminino , Humanos , Masculino , Fenótipo , Fatores Sexuais , Febre Tifoide/sangueRESUMO
El estudio de factores genéticos asociados a enfermedades infecciosas representa un área de investigación promisoria para la optimización de futuras políticas de su manejo y control. En fiebre tifoidea, uno de nuestros mayores problemas de salud, este enfoque ha sido esporádico e infructuoso, por haber sido dirigidos a estudiar la susceptibilidad total a la enfermedad. Más aún, las dificultades en el reconocimiento de subgrupos clínicos han impedido la definición de fenotipos clínicos inequívocos apropiados para estos fines. Con el fin de buscar bases para la identificación de fenotipos, o expresiones definidas de la enfermedad, que permitan intentar la caracterización de subpoblaciones para el estudio de factores genéticos, se hizo una revisión de la literatura nacional y extranjera del período 1960-88. En ésta se encontró información en las áreas de la experimentación animal, inmunogenética humana, epidemiología y clínica, que permite proponer cinco fenotipos para el desarrollo de modelos clínico-epidemiológicos: la duración del período de incubación, la recaída, la respuesta en aglutininas (reacción de Widal), la respuesta a la vacunación y el comportamiento metabólico de ciertos fármacos, incluidos los antibióticos. Se propone que uno o más de estos fenotipos y su posible asociación con sistemas polimorfos, podrían conducir al reconocimiento de subpoblaciones en fiebre tifoidea
Assuntos
Humanos , Febre Tifoide/genética , Chile , RecidivaRESUMO
The study of genetic factors associated to infectious diseases is a promising research field for optimizing their management and control in the future. For typhoid fever, one of our major health problems, this approach has been sporadic an fruitless for having been addressed to disease's overall susceptibility. Moreover, difficulties on recognition of clinical sub-sets have prevented definition of unambiguous clinical phenotypes appropriate for this objective. With the aim of finding the basis for phenotypes identification, or definite disease expressions, a search including foreign and national literature was carried out for the 1960-88 period. From animal experimentation, human immunogenetics, epidemiology and clinical literature, data was obtained for proposing five phenotypes: the incubation period, typhoid relapse, agglutinins response (Widal's test), response to vaccination and metabolic behaviour of certain substances, including antibiotics. That one or more of these phenotypes and their possible association with polymorphic systems might lead to populational subsets recognition in typhoid fever is suggested.
Assuntos
Febre Tifoide/genética , Animais , Criança , Humanos , Camundongos , Recidiva , Febre Tifoide/complicações , Febre Tifoide/epidemiologia , Febre Tifoide/imunologiaRESUMO
Descendants of Dutch colonists, who emigrated to Surinam in the last century and survived epidemics of typhoid and yellow fever with a total mortality of about 60%, were tested for twenty-six polymorphisms. The gene frequencies were compared with those of a large Dutch control sample. An analysis of drift indicated that the variations in gene frequencies observed for C3, Gm, HLA-B, and GLO were unlikely to be due to drift. Therefore these data might indicate selection through genetic control of survival in these epidemics.