RESUMO
The so-called tumor necrosis factor (TNF) block includes the TNFA, lymphotoxin alpha and beta (LTA and LTB) genes with single-nucleotide polymorphisms (SNP) and microsatellites with an allele frequency that exhibits interpopulation variability. To date, no reports have included both SNPs and microsatellites at the TNF block to study Mestizo or Amerindian populations from Mexico. In this study, samples of five Mexican Mestizo populations (Durango, Guadalajara, Monterrey, Puebla, and Tierra Blanca) and four native-Mexican populations (North Lacandonians, South Lacandonians, Tepehuanos, and Yaquis) were genotyped for two SNPs (LTA+252A>G and TNFA-308G>A) and four microsatellites (TNFa, d, e, and f), to analyze the genetic substructure of the Mexican population. Allele and haplotype frequencies, linkage disequilibrium (LD), and interpopulation genetic relationships were calculated. There was significant LD along almost all of the TNF block but the lowest D' values were observed for the TNFf-TNFd pair. Mestizos showed higher allele and haplotype diversity than did natives. The genetic differentiation level was reduced among Mestizos; however, a slightly, but significant genetic substructure was observed between northern and southern Mexican Mestizos. Among the Amerindian populations, the genetic differentiation level was significantly elevated, particularly in both North and South Lacandonians. Furthermore, among Southern Lacandonians, inhabitants of Lacanja town were the most differentiated from all the Mexicans analyzed. The data presented here will serve as a reference for further population and epidemiological studies including these TNF polymorphisms in the Mexican population.
Assuntos
Haplótipos , Indígenas Norte-Americanos/genética , Desequilíbrio de Ligação , Repetições de Microssatélites , Polimorfismo de Nucleotídeo Único , Fator de Necrose Tumoral alfa/genética , Feminino , Humanos , Masculino , MéxicoRESUMO
Because concurrent infections with geohelminth parasites might impair the immune response to oral vaccines, we studied the vibriocidal antibody response to the oral cholera vaccine CVD 103-HgR in children infected with Ascaris lumbricoides and investigated the effect of albendazole pretreatment on the postvaccination response. Children with ascariasis were randomized to receive either 2 sequential doses of 400 mg of albendazole or placebo. After the second dose, CVD 103-HgR was given, and serum vibriocidal antibody levels were measured before and 10 days after vaccination. Postvaccination rates of seroconversion were greater in the treatment group that received albendazole (P=.06). Significantly greater rates of seroconversion and geometric mean titer were observed in the albendazole group in subjects with non-O ABO blood groups. A significant association was observed between vibriocidal seroconversion rates and treatment group, suggesting that A. lumbricoides infections impair the immune response to oral cholera vaccine, particularly in subjects of non-O blood groups.
Assuntos
Albendazol/uso terapêutico , Anti-Helmínticos/uso terapêutico , Anticorpos Antibacterianos/sangue , Ascaríase/tratamento farmacológico , Ascaríase/imunologia , Ascaris lumbricoides , Vacinas Bacterianas/imunologia , Vacinas contra Cólera/imunologia , Vacinas Atenuadas/imunologia , Adolescente , Animais , Formação de Anticorpos , Ascaris lumbricoides/efeitos dos fármacos , Antígenos de Grupos Sanguíneos/imunologia , Criança , Interações Medicamentosas , Equador , Feminino , Humanos , Masculino , Trichuris/efeitos dos fármacosRESUMO
The roles of eotaxin, RANTES, and MCP-3 expression in eosinophil recruitment to the site of parasite killing that occurs following ivermectin treatment of onchocerciasis were assessed in the skin of 13 Onchocerca volvulus-infected subjects and two noninfected controls before and after ivermectin treatment. Adverse reactions in infected subjects were associated with the appearance of eosinophils in the dermis as part of a perivascular inflammatory infiltrate. Although no expression of RANTES and eotaxin was seen in dermal vascular endothelial cells in biopsies taken before treatment (nor at any time in the skin of uninfected controls), endothelial expression of both eotaxin and RANTES was noted by 24 h following treatment. While RANTES expression was transient, eotaxin expression increased in parallel with increasing eosinophil recruitment up to 60 h posttreatment. These observations indicate that endothelial expression of eotaxin and RANTES may have an important role in eosinophil recruitment into the skin during helminth-killing reactions.
Assuntos
Quimiocinas CC , Quimiocinas/biossíntese , Derme/imunologia , Endotélio Vascular/imunologia , Eosinofilia/imunologia , Ivermectina/uso terapêutico , Onchocerca volvulus/imunologia , Oncocercose/imunologia , Adulto , Animais , Biópsia , Quimiocina CCL11 , Quimiocina CCL5/biossíntese , Quimiotaxia de Leucócito , Citocinas/biossíntese , Procedimentos Cirúrgicos Dermatológicos , Derme/irrigação sanguínea , Equador , Feminino , Humanos , Ivermectina/efeitos adversos , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Oncocercose/tratamento farmacológicoRESUMO
In the course of an epidemiologic survey in Ecuador, the following collection of Leishmania stocks was isolated: 28 from patients with clinical signs of leishmaniasis, 2 from sloths, 1 from a dog, and 4 from sand flies. For genetic characterization of these stocks, multilocus enzyme electrophoresis (MLEE) and random amplified polymorphic DNA (RAPD) were used. Twenty six of the 35 stocks were identified as either Leishmania (V.) panamensis or L. (V.) guyanensis, 2 stocks were identified as L. (V.) braziliensis, the 2 stocks from sloths showed specific genotypes, and 5 stocks were characterized as hybrids between L. (V.) braziliensis and L. (V.) guyanensis. These data show that genetic diversity of Leishmania in Ecuador is high and that L. (V.) panamensis/guyanensis is the dominant group in this country. The genetic analysis questioned the distinctness between the two species L.(V.) panamensis and L. (V.) guyanensis, since MLEE and RAPD data did not indicate that L. (V.) panamensis and L. (V.) guyanensis correspond to distinct monophyletic lines. Population genetic analysis performed on the L. (V.) panamensis/guyanensis group favors the hypothesis of a basically clonal population structure.
Assuntos
Variação Genética/genética , Leishmania guyanensis/genética , Leishmaniose Mucocutânea/parasitologia , Animais , Cães , Equador , Eletroforese em Acetato de Celulose , Glucosefosfato Desidrogenase/química , Humanos , Isoenzimas/química , Isoenzimas/genética , Leishmania guyanensis/classificação , Leishmania guyanensis/enzimologia , Leishmaniose Mucocutânea/enzimologia , Filogenia , Psychodidae , Técnica de Amplificação ao Acaso de DNA Polimórfico , Bichos-PreguiçaRESUMO
The taxonomic attribution of four Leishmania stocks isolated from humans in Ecuador has been explored by both multilocus enzyme electrophoresis and random amplified polymorphic DNA. For three loci, MLEE results showed patterns suggesting a heterozygous state for a diploid organism, while the corresponding homozygous states are characteristic of the Leishmania panamensis/guyanensis complex and Leishmania braziliensis, respectively. Other enzyme loci showed characters attributable to either the L. panamensis/ guyanensis complex or L. braziliensis. RAPD profiles exhibited for several primers a combination of the Leishmania panamensis/ guyanensis complex and L. braziliensis characters. These data hence suggest that the four stocks are the result of hybridization between L. panamensis/guyanensis and L. braziliensis. MLEE data show that the results cannot be attributed to either mixture of stocks, or an F1 in the framework of a simple Mendelian inheritance.
Assuntos
Quimera/genética , Leishmania braziliensis/genética , Leishmania guyanensis/genética , Filogenia , Animais , DNA de Protozoário/análise , Equador , Eletroforese em Acetato de Celulose/métodos , Humanos , Isoenzimas/análise , Leishmania braziliensis/enzimologia , Leishmania guyanensis/enzimologia , Leishmaniose Cutânea/parasitologia , Leishmaniose Mucocutânea/parasitologia , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
The fragile X (fra-X) syndrome is the most frequent form of inherited mental retardation. Facial dysmorphism, macroorchidism and a folate-sensitive fragile site on Xq27.3 are commonly associated features. The gene causing this disorder, designated as FMR1, is X-linked and shows an unusual inheritance mode. A multistep amplification of the CGG repeats at the 5' end of the FMR1 gene has been recently identified as the cause of the fra-X syndrome. Different numbers of repeats define three gene forms (normal, premutated and mutated), whose ranges show little variation in the populations studied so far. We analyzed 18 Mexican individuals with the fra-X syndrome, 40 of their relatives (first and second degree), and 76 healthy individuals without antecedents of mental retardation. Southern blot and PCR permitted the assessment of the number of CGG repeats and the methylation state of the FMR1 gene for the normal, premutated, and mutated alleles. The results showed no statistical differences when compared with those from other populations. No cytogenetic expression of the Xq27.3 fragile site in 50% of the affected males and in all the affected and carrier females was observed. This finding emphasizes the necessity of a molecular analysis in fra-X cases and their relatives in order to provide a more adequate genetic counseling.
Assuntos
Síndrome do Cromossomo X Frágil/genética , Genética Populacional , Sequência de Bases , Estudos de Casos e Controles , Feminino , Humanos , Masculino , México , Dados de Sequência MolecularRESUMO
In two endemic leishmaniasis foci of the Pacific coast of Ecuador 34 dogs suspected of having the disease have been surveyed clinically, serologically and parasitologically; immunofluorescence and electrosyneresis tests, lymph node aspirates, biopsies and smears have been performed. From two dogs with ulcers only one had ulcers on the muzzle and the scrotum infected by Leishmania (L. guyanensis complex). The isolated strain was identified as Leishmania panamensis. The disease was strictly cutaneous. In the study area the dog seems to be more a victim-host than a reservoir.