[Natural history of occupational hearing loss induced by noise]. / História natural da perda auditiva ocupacional provocada por ruído.

PURPOSE: To evaluate the clinical and audiometric characteristics of occupational hearing loss induced by noise, according to age and time of exposition in years. METHODS: 222 patients with occupational sensorineural hearing loss induced by noise were studied retrospectively, correlating the auditive clinical claims, alterations of audiometric thresholds at frequencies of 250 Hz to 8000 Hz, speech discrimination indicator with age and time of exposure. As a control group were used the audiometric threshold of a population of same medium age, without morbid antecedents of hearing illness, as preconized by ISO 1999 (1990). The group were divided into subgroups and three decades of exposure were analyzed. RESULTS: It was verified that the clinical claims of hipoacusia increases according to the age and time of exposure. The frequency of tinnitus is constant. The audiometric thresholds in the second decade of exposure present variations that depend on the age. The several audiometric curves are parallel, but they are not horizontal. The worst thresholds were found in the high frequencies from 3000 Hz to 8000 Hz, as a clinical and physiopathological consequences of the commitment of basal areas of cochlea. The speech discrimination showed to be worst according to the increase of age and time of exposure. CONCLUSION: Patients with hearing loss disacusia induced by occupational noise present characteristic audiometric thresholds that vary according to age and time of exposure to noise. These characteristics defined and resumed in audiometric curves can constitute a standard of comparison, evaluation and control for exposed populations.

História natural da perda auditiva ocupacional provocada por ruído / Natural history of the occupational hearing loss induced by noise

OBJETIVO: Analisar as características clínicas e audiométricas da disacusia sensórioneural ocupacional por ruído de acordo com a faixa etária e o tempo de exposição em anos. MÉTODO: Foram estudados retrospectivamente 222 pacientes portadores de disacusia sensórioneural ocupacional decorrente da exposição ao ruído no ambiente de trabalho, correlacionando-se as queixas clínicas auditivas, alterações de limiar audiométrico nas freqüências de 250Hz a 8000Hz, índices de discriminação vocal com a faixa etária e o tempo de exposição. Como grupo controle, utilizou-se os limiares audiométricos de uma população de mesma média etária, sem antecedentes mórbidos de doença auditiva, conforme preconiza a norma ISO 1999 (1990). O grupo foi dividido em subgrupos, tendo-se analisado três décadas de exposição. RESULTADOS: Verificamos que a queixa clínica de hipoacusia aumenta de acordo com a faixa etária e o tempo de exposição, enquanto que a freqüência da queixa tinnitus mantém-se constante. Os Limiares audiométricos na segunda década de exposição apresentam variações que dependem da faixa etária analisada. As várias curvas audiométricas realizadas são paralelas entre si, mas não-horizontais, sendo que os piores limiares foram encontrados nas freqüências agudas de 3000Hz a 8000Hz, como conseqüência clínica e fisiopatológica do acometimento mais acentuado das áreas basais da cóclea. A discriminação vocal também mostrou-se pior de acordo com o aumento das faixa etária e do tempo de exposição. CONCLUSÃO: Indivíduos portadores de disacusia sensórioneural por ruído ocupacional apresentam alterações audiométricas, características que variam de acordo com a faixa etária e o tempo de exposição. Estas características definidas e resumidas nas curvas audiométricas obtidas podem constituir padrão de comparação, avaliação e controle de outras populações também expostas.

[Normal hematologic parameters]. / Parâmetros hematológicos normais.

Hematological studies by several Brazilian and other Latin-American authors who give parameters considered as normal for different populations have been reviewed. Results showed significant differences, due to social, environmental and nutritional factors as well as to different methodological procedures and also to age, sex, race, occupation and other individual characteristics. Three Brazilian studies were selected in the light of the wide variety of parameters included. Ranges are presented as a demonstration of the variations in such samples, presumably considered "normal" by the respective authors presumably "normal". One of the purposes of the present study is to establish the basis for future investigation into the effects of industrialization on the ranges of the hematological parameters of individuals taken to be normal.

[Comparative study of the intradermal reaction performed with whole lepromin and ultrasonic-treated lepromin in normal subjects]. / Estudo comparativo da intradermo-reaçao praticada com lepromina integral e com lepromina tratada porultrasom em individuos normais.

A comparative study on the Fernandez and on the Mitsuda reaction was made in 104 normal people employing whole and sonicated lepromin. Both types of lepromin can induce a good early reaction, and there was no significant difference in the results of the Fernandez reaction. The sonicated lepromin, though it contains all of the components of the original preparation, gives weaker late skin reactions. The results of the Mitsuda reaction were statistically significant.