Cuestionario de reacciones vasovagales a la donación de sangre en una institución de salud / Questionnaire of vasovagal reactions to blood donation in a health institution

Resumen: Objetivo: Identificar mediante un cuestionario de signos y síntomas vasovagales a donadores de sangre, con el fin de registrar los antecedentes que aumentan la probabilidad de presentar reacciones vasovagales. Materiales y Métodos: Se aplico un cuestionario a donadores de sangre, durante tres meses, en el banco de sangre en una institución de salud de tercer nivel. Resultados: El 100% de los donadores respondió negativamente a las preguntas del cuestionario, pero el 1.3% de ellos presentaron reacción vasovagal, siendo el mareo, palidez y náusea el signo y síntomas más frecuentemente mostrados. Al comparar dos grupos con y sin reacción vasovagal pareados por sexo, edad e índice de masa corporal, no hubo diferencias entre ellos. Conclusiones: Los donadores en nuestro país son fundamentalmente de reemplazo, por lo que se debe considerar esta circunstancia además de sus motivaciones, para el diseño de encuestas dirigidas a esta población.

Abstract: Objective: Identify, trough a vasovagal signs and symptoms questionnaire, blood donors in order to record the antecedents that increases the probability of presenting vasovagal reactions. Materials and Methods: A questionnaire was applied to blood donors, for three months, in the blood bank in a third-level health institution. Results: 100% of the donors answered negatively to the questions in the questionnaire, but 1.3% of them presented vasovagal reaction, with dizziness, pallor and nausea being the most frequently shown sing and symptoms. When comparing two groups with and without vasovagal reaction matched by sex, age and body mass index, there were no differences between them. Conclusions: Donors in our country are fundamentally replacement donors, so this circumstance plus their motivations should be considered for the design of surveys aimed at this population.

Estudio genético del síncope vasovagal asociado al polimorfismo Arg389Gly del receptor adrenérgico beta1 / Genetic study of the vasovagal syncope associated to the Arg389Gly polymorphism of the beta1 adrenergic receptor

The purpose of this study was to evaluate the correlation between the vasovagal syncope (VVS) and the beta1 adrenergic receptor polymorphism at the 389 position. Seventy individuals with VVS were selected. DNA was extracted from peripheral blood by salting out and subjected to the amplification-restriction test. Genotype identification was made by polyacrylamide gel electrophoresis. A higher frequency in genotype and allele frequencies were found in individuals with positive tilted table test respect individuals with negative test, as well as a marked preference of the GlyGly phenotype in women. Genotype Arg389Gly was the most frequent between individuals with positive response in passive phase with respect to those in the induced phase. When the genotype was analyzed based on the hemodynamic response (VASIS) a gradient is observed in the frequency of Arg389Gly with the highest major frequency in the cardio-inhibitory response followed by the mixed response, and finally the vasodepressor response. These results suggest that the SVV has a genetic component associated with the Arg389Gly polymorphism of the adrenergic receptor. The Gly allele has a high risk association and it is maintained in the population through heterozygosis.

Detección de una mutación en el gen KCNQ1 (KvLQT1) causante de síndrome de Jervell, Lange-Nielsen en una familia mexicana / KCNQ 1 (KvLQT1) missense mutation causing congenital long QT syndrome (Jervell-Lange-Nielsen) in a Mexican family

BACKGROUND: Long QT syndromes (LQTS) are inherited cardiac disorders caused by mutations in the genes that encode sodium or potassium transmembrane ion channel proteins. More than 200 mutations, in at least six genes, have been found in these patients. The Jervell and Lange-Nielsen (JLN) syndrome is the recessive form of the disease and is associated with deafness. Few families with JLN syndrome and genetic studies are reported in the literature. METHODS: The KCNQ1 (KvLQT1) gene in a Mexican family with Jervell-Lange-Nielsen long QT syndrome was analyzed using an automated sequence method. RESULTS: A missense mutation was found in the three affected individuals. This mutation is associated with complete loss of channel function. Correlation with the phenotype showed a prolonged QTc interval and deafness in the two siblings homozygous to the mutation. The mother, who was heterozygous for the mutation, also had prolonged QTc interval without deafness. The father and younger brother had normal QTc intervals. The mutation was not found in 50 healthy controls studied. CONCLUSIONS: We describe for the first time a mutation in the KCNQ1 gene in a Mexican family with JLN long QT syndrome. This mutation produces an amino acid change (Gly-Arg) at protein level at the 168 residue. This mutation has been previously reported in Caucasian families with LQTS.