ABSTRACT
Mitochondrial mutations are responsible for at least 1 percent of the cases of hereditary deafness, but the contribution of each mutation has not yet been defined in African-derived or native American genetic backgrounds. A total of 203 unselected hearing-impaired patients were screened for the presence of the mitochondrial mutation A1555G in the 12S rRNA gene and mutations in the tRNA Ser(UCN) gene in order to assess their frequency in the ethnically admixed Brazilian population. We found four individuals with A1555G mutation (2 percent), which is a frequency similar to those reported for European-derived populations in unselected samples. On the other hand, complete sequencing of the tRNA Ser(UCN) did not reveal reported pathogenic substitutions, namely A7445G, 7472insC, T7510C, or T7511C. Instead, other rare substitutions were found such as T1291C, A7569G, and G7444A. To evaluate the significance of these findings, 110 "European-Brazilians" and 190 "African-Brazilians" unrelated hearing controls were screened. The T1291C, A7569G and G7444A substitutions were each found in about 1 percent (2/190) of individuals of African ancestry, suggesting that they are probably polymorphic. Our results indicate that screening for the A1555G mutation is recommended among all Brazilian deaf patients, while testing for mutations in the tRNA Ser(UCN) gene should be considered only when other frequent deafness-causing mutations have been excluded or in the presence of a maternal transmission pattern.
Subject(s)
Female , Humans , Male , Hearing Loss/genetics , Mutation/genetics , RNA, Ribosomal/genetics , RNA, Transfer, Ser/genetics , Black People/genetics , Brazil , Case-Control Studies , DNA Mutational Analysis , White People/genetics , Genetic Predisposition to Disease , Genetic Markers/genetics , Pedigree , Polymerase Chain Reaction , RNA , Severity of Illness IndexABSTRACT
A análise dos procedimentos cirúrgicos relacionando-os a real necessidade de hemocomponentes possibilitou a elaboração de uma listagem estabelecendo-se a conduta para as cirurgias eletivas do Hospital. Como critérios foram utilizados a complexidade do procedimento cirúrgico e a quantidade de concentrados de hemácias efetivamente transfundidos. Importante ressaltar como primordial a avaliaçãoo clínica/laboratorial pré-operatória para estabelecer a necessidade de suporte hemoterápico mesmo em procedimentos menos complexos. Esta conduta foi submetida aos coordenadores médicos de cada especialidade e aprovada pelo Comitê de Hemoterapia do Hospital. Desde sua implantação o estoque de concentrados de hemácias da AT foi adequado, diminuindo sua perda e proporcionando um impacto positivo no custo operacional de nosso serviços.