HLA-DQA1 allele typing by nonisotopic PCR-LIS-SSCP

In the present study we used a simple and reliable method for HLA-DQA1 allele typing based on the single-stranded conformation polymorphism (SSCP) properties of DNA molecules obtained by PCR. The technique consists of PCR amplification of a DNA fragment comprising the second exon of the HLA-DQA1 gene, amplicon denaturation using a low ionic strength solution (LIS), and electrophoresis on a small native polyacrylamide gel, followed by a rapid silver staining procedure. In order to validate the technique and to obtain the allele patterns for the DQA1 gene, 50 cervical samples were typed using this methodology and the commercial Amplitype® HLA DQA1 Amplification and Typing kit. All the alleles detected with the kit were characterized by the LIS-SSCP approach. This procedure proved to be useful for population screening and typing of the DQA1 gene as well as for detecting new alleles or mutations in the donor-recipient molecular matching of HLA class II genes.Facultad de Ciencias Veterinaria

Evaluation of p53 codon 72 polymorphism in adenocarcinomas of the colon and rectum in La Plata, Argentina

Aim: To evaluate the potential association between p53 codon 72 polymorphism and sporadic colorectal adenocarcinoma development, and human papillomavirus (HPV) infection. Methods: One-hundred and nine controls and 53 patients with colon cancer from the city of La Plata, Argentina were analyzed. p53 codon 72 genotypes and HPV infection were identified using allele-specific polymerase chain reaction and nested polymerase chain reaction, respectively. Results: The differences in the distribution of p53 codon 72 polymorphism between the cases and controls were statistically significant. The arginine allele had a prevalence of 0.65 in controls and 0.77 in cases. The corresponding odds ratio for the homozygous arginine genotype was 2.08 (95% CI, 1.06-4.05; P<0.05). Lack of association was found between p53 polymorphism and HPV infection in the set of adenocarcinomas. Conclusion: The findings of the present study indicate that p53 codon 72 arginine homozygous genotype may represent a genetic predisposing factor for colon cancer development. However, further studies are needed in order to elucidate the role of p53 codon 72 polymorphism in colorectal cancer.Facultad de Ciencias Veterinaria

HLA-DQA1 allele typing by nonisotopic PCR-LIS-SSCP

In the present study we used a simple and reliable method for HLA-DQA1 allele typing based on the single-stranded conformation polymorphism (SSCP) properties of DNA molecules obtained by PCR. The technique consists of PCR amplification of a DNA fragment comprising the second exon of the HLA-DQA1 gene, amplicon denaturation using a low ionic strength solution (LIS), and electrophoresis on a small native polyacrylamide gel, followed by a rapid silver staining procedure. In order to validate the technique and to obtain the allele patterns for the DQA1 gene, 50 cervical samples were typed using this methodology and the commercial Amplitype® HLA DQA1 Amplification and Typing kit. All the alleles detected with the kit were characterized by the LIS-SSCP approach. This procedure proved to be useful for population screening and typing of the DQA1 gene as well as for detecting new alleles or mutations in the donor-recipient molecular matching of HLA class II genes.Facultad de Ciencias Veterinaria

Evaluation of p53 codon 72 polymorphism in adenocarcinomas of the colon and rectum in La Plata, Argentina

Aim: To evaluate the potential association between p53 codon 72 polymorphism and sporadic colorectal adenocarcinoma development, and human papillomavirus (HPV) infection. Methods: One-hundred and nine controls and 53 patients with colon cancer from the city of La Plata, Argentina were analyzed. p53 codon 72 genotypes and HPV infection were identified using allele-specific polymerase chain reaction and nested polymerase chain reaction, respectively. Results: The differences in the distribution of p53 codon 72 polymorphism between the cases and controls were statistically significant. The arginine allele had a prevalence of 0.65 in controls and 0.77 in cases. The corresponding odds ratio for the homozygous arginine genotype was 2.08 (95% CI, 1.06-4.05; P<0.05). Lack of association was found between p53 polymorphism and HPV infection in the set of adenocarcinomas. Conclusion: The findings of the present study indicate that p53 codon 72 arginine homozygous genotype may represent a genetic predisposing factor for colon cancer development. However, further studies are needed in order to elucidate the role of p53 codon 72 polymorphism in colorectal cancer.Facultad de Ciencias Veterinaria

In-House Validation of Rapid Detection PCRs for Bacterial Pathogens Causing Infant Diarrhea

In Argentina, conventional culture methods for the isolation of diarrheal bacteria continue to be the most widely used form of diagnosis in many clinical laboratories. In this work we validated 11 in-house real-time polymerasechain reactions (PCRs) assays for the specific and rapid detection of Salmonella spp., Shigella spp., enteroinvasive E. coli, enteropathogenic E. coli, enterotoxigenic E. coli, Shiga toxin-producing E. coli, E. coli O157, Cronobacter sakazakii, Campylobacter jejuni, Campylobacter coli, Vibrio cholera and Clostridium difficile. The sensitivity of the assays was less than 100 CFU/ml for all the studied pathogens; selectivity and specificity were 100% in all cases and robustness was optimal. These PCR methods could be used to accurately detect the main bacterial causes of infant gastroenteritis.Fil: Londero, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Leotta, Gerardo Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Brusa, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Costa, Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Golijow, Carlos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Gutkind, Gabriel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Gonzalez, E.. Centro de Diagnóstico Molecular S.A.; ArgentinaFil: Galli, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin

In-House Validation of Rapid Detection PCRs for Bacterial Pathogens Causing Infant Diarrhea

In Argentina, conventional culture methods for the isolation of diarrheal bacteria continue to be the most widely used form of diagnosis in many clinical laboratories. In this work we validated 11 in-house real-time polymerasechain reactions (PCRs) assays for the specific and rapid detection of Salmonella spp., Shigella spp., enteroinvasive E. coli, enteropathogenic E. coli, enterotoxigenic E. coli, Shiga toxin-producing E. coli, E. coli O157, Cronobacter sakazakii, Campylobacter jejuni, Campylobacter coli, Vibrio cholera and Clostridium difficile. The sensitivity of the assays was less than 100 CFU/ml for all the studied pathogens; selectivity and specificity were 100% in all cases and robustness was optimal. These PCR methods could be used to accurately detect the main bacterial causes of infant gastroenteritis.Instituto de Genética Veterinari

Evaluación de la población de ganado bovino criollo argentino de la Estación Zootécnica Subtropical Arroyo del Medio (provincia de Jujuy) mediante la utilización del marcador genético molecular BoLA-DRB3

Se estudió la variabilidad genética en el locus. BoLA-DRB5 de la población de ganado bovino Criollo Argentino localizada, en la Estación Zootécnica Subtropical Arroyo del Medio (Provincia de Jujuy). Algunas características de la población analizada son comunes a las de otros rodeos de la raza estudiados previamente Sin embargo, el rodeo de Arroyo del Medio presento características propias como la presencia de las variantes alélicas DRB3.2~5, DRB3.2~10, DRB3.2~20 y DRB3.2~24 del locus BoLA-DRB3 con frecuencias superiores al 10%. A pesar del aislamiento geográfico sufrido por un largo lapso y el reducido tamaño de la población, el análisis de los resultados muestra una elevada heterocigosis, sin que se observe la fracción de alguna de las variantes alélicas para el locus estudiado. Las frecuencias genotípicas estimadas para el locus BOLA-DRB3 indican que la Población se encontraría en equilibrio de Hardy-Weinberg. A partir de los datos observados en el presente trabajo surge que cuando se analiza un locus muy polimórfico como el BoLA-DRB3, el tamaño poblacional resulta ser insuficiente para el mantenimiento de todas las variantes presentes en la raza.The genetic variability of the locus BoLA-DRB3 was studied in a population of Argentine Creole cattle located in the Estacion Zootécnica Subtropical Arroyo del Medio (Province of Jujuy Argentine). The population studied had similar features with other herds of Argentine Creole cattle previously studied However the herd of Arroyo del Medio allowed its own characteristic, as it allelic variants DRB3.2~5, DRB3.2~10, DRB3.2~20 and DRB3.2~24 locus with frequencies higher than 10%. The population size and mating system could be enough to avoid the increment of inbreeding. From the data obtained it can be seen that the population had all the allelic variant reported for the breed for loci with low polymorphism For a high polymorphic locus, like BoLA DRB3 the population size was not sufficient to conserve all the allelic variant.Facultad de Ciencias Veterinaria

Genetic variability and population structure in loci related to milk production traits in native Argentine Creole and commercial Argentine Holstein cattle

Many cattle breeds have been subjected to high selection pressure for production traits. Consequently, population genetic structure and allelic distribution could differ in breeds under high selection pressure compared to unselected breeds. Analysis of k-casein, αS1-casein and prolactin gene frequencies was made for Argentine Creole (AC) and Argentine Holstein (AH) cattle herds. The calculated FST values measured the degree of genetic differentiation of subpopulations, depending on the variances of gene frequencies.The AC breed had considerably more variation among herds at the αS1-casein and k-casein loci. Conservation strategies should consider the entire AC population in order to maintain the genetic variability found in this native breed.Facultad de Ciencias Veterinaria

Utilidad del jugo gástrico en el diagnóstico de infección por <i>Helicobacter pylori</i> : Parte I: Correlación entre los hallazgos histológicos y los hallazgos en el jugo gástrico

Estudios anteriores, hemos comprobado que la prevalencia de infección por Helicobacter pylori en pacientes dispépticos con mucosas gástricas sin alteraciones o con una leve gastritis, llegaba al 76,19%, mientras que en pacientes con daño de la mucosa de moderado a severo, la prevalencia de la infección llegaba al 100%. Aún más, pudimos determinar que existía una muy fuerte asociación entre la intensidad del daño histológico de la mucosa y la presencia del factor de virulencia CagA. Aunque la infección por H. pylori cursa generalmente de forma asintomática, casi todas las personas infectadas por este bacilo presentan, en algún momento de su vida, inflamación gástrica. La infección por H. pylori es la causa principal del desarrollo de úlcera péptica, la que afecta aproximadamente al 15% de los pacientes portadores (Toljamo y col., 2002; Crespo y Suh, 2001). La infección por H. pylori induce la gastritis superficial crónica, la que se caracteriza por presentar infiltración mononuclear y polinuclear de la mucosa, con la consecuente injuria de las células epiteliales. En los Estados Unidos, el patrón de inflamación gástrica más predominante es la que involucra al antro, encontrándose más estrechamente ligado a la úlcera de duodeno. Sin embargo, en los países en desarrollo el tipo de inflamación predominante es la pangastritis, la que ha sido asociada tanto a la úlcera como al carcinoma gástrico (Atherton y Blase, 1997). Considerando que el jugo gástrico baña uniformemente la superficie mucosa del estómago y, por lo tanto, podrían transferirse a él algunos signos sugerentes o indicativos de daño inflamatorio como también algunas formas bacilares o cocoides de H. pylori, se estudiaron 149 muestras de jugo gástrico obtenido de otros tantos pacientes dispépticos sometidos a una endoscopía alta, determinando la presencia o ausencia de células inflamatorias y la presencia o ausencia de estructuras bacterianas compatibles con H. pylori, correlacionando los hallazgos con los obtenidos de biopsias antrales obtenidas simultáneamente durante el mismo acto endoscópico.Facultad de Ciencias Médicas (FCM

Type-Specific Identification of Genital Human Papillomavirus Infection in Women with Cytological Abnormality

Objectives: To estimate the frequency of human papillomavirus (HPV) infection and the genotype distribution of HPV among women with a Pap smear showing atypical squamous cells of undetermined significance (ASC-US) attending the Program for the Detection and Control of Cervical Cancer in Bogotá, Colombia. Study Design: Cervical samples from 200 women with an ASC-US Pap smear were analyzed for the presence of HPV DNA and genotype distribution using a commercial molecular technique (Linear Array®; Roche Molecular Systems, USA). Results: HPV infection was found in 140 women (70%). High-risk HPV types were present in 46.4% of the samples; 16.4% showed a low-risk HPV type, and 37.1% showed both. Of the positive samples, 42.9% were infected with a single viral genotype, whereas 57.1% exhibited multiple HPV infections. The most common HPV genotypes were HPV 16, 53, and 52 with a prevalence of 26.4, 16.4, and 13.6%, respectively. Conclusion: The epidemiological characterization of HPV infections described in this study might guide actions for epidemiological surveillance to strengthen the program in Bogotá and to develop appropriate HPV vaccination programs.Instituto de Genética Veterinari