Association between interleukin-6 polymorphism in the -174 G/C region and hearing loss in the elderly with a history of occupational noise exposure / Associação entre interleucina-6 polimorfismo na região de -174 G/C e perda auditiva em idosos com história de exposição ao ruído ocupacional

INTRODUCTION: The biological processes involved in noise-induced hearing loss (NIHL) are still unclear. The involvement of inflammation in this condition has been suggested. OBJECTIVE: To investigate the association between interleukin - 6 (IL-6) polymorphism and susceptibility to NIHL. METHODS: This was a cross-sectional study with a sample of 191 independent elderly individuals aged > 60 years of age. Information on exposure to occupational noise was obtained by interviews. Audiological evaluation was performed using pure tone audiometry and genotyped through PCR by restriction fragment length polymorphism - PCR-RFLP. Data were analyzed using the Chi-square test and the Odds ratio (OR), with the significance level set at 5%. RESULTS: Among elderly with hearing loss (78.0%), 18.8% had a history of exposure to occupational noise. There was a statistically significant association between the genotype frequencies of the IL-6 -174 and NIHL. The elderly with the CC genotype were less likely to have hearing loss due to occupational noise exposure when compared to those carrying the GG genotype (OR = 0.0124; 95% CI 0.0023-0.0671; p < 0.001). CONCLUSION: This study suggests there is an association of polymorphisms in the IL- 6 gene at position - G174C with susceptibility to noise-induced hearing loss. .

INTRODUÇÃO: Os processos biológicos envolvidos na perda auditiva induzida por ruído (PAIR) ainda não estão claros. O envolvimento de processo inflamatório nesta condição tem sido sugerido. OBJETIVO: Investigar a associação entre o polimorfismo no gene da interleucina-6 (IL-6) e a suscetibilidade à PAIR. MÉTODO: Trata-se de estudo transversal com amostra de 191 idosos independentes acima de 60 anos de idade. Informações sobre a exposição ao ruído ocupacional foram obtidas por entrevistas. A avaliação audiológica foi realizada por meio de audiometria tonal liminar e a genotipagem pela técnica da PCR-RFLP. Os dados foram analisados usando-se o teste Qui-quadrado e a razão de chances (OR), com o nível de significância fixado em 5%. RESULTADOS: Entre os idosos com perda auditiva (78,0%), 18,8% apresentavam histórico de exposição ao ruído ocupacional. Houve associação estatisticamente significante entre as frequências genotípicas da IL-6 -174 e a PAIR. Os idosos portadores do genótipo CC foram menos propensos a apresentar perda auditiva por exposição ao ruído ocupacional quando comparados a aqueles portadores do genótipo GG (OR = 0,0124; 95% IC 0,0023-0,0671; p < 0,001). CONCLUSÃO: O presente estudo sugere a associação do polimorfismo no gene da IL-6 na posição -G174C com a suscetibilidade à perda auditiva induzida por ruído. .

Genotypic diversity and virulence factors of Streptococcus mutans in caries-free and caries-active individuals

The objective of this study was to analyze the genotypic diversity, frequency of serotypes and the detection of mutacins from Streptococcus mutans isolates in caries-free and caries-active individuals.A total of 260 S. mutans isolated from 28 individuals with and without dental caries were subjected to AP-PCR and PCR screening of glucosyltransferase B, mutacin and serotype genes, which showed the presence of. 70 different genotypes. There was no statistically significant association between the presence of genes for serotypes and mutacins with dental caries. However, there was a statistically significant and a strong association between the higher genotypic diversity in the subjects with caries (r = 0.72, p = 0.001). There was an increase in the number of genotypes with increasing age (p <0.01).