[Natural history of occupational hearing loss induced by noise].

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).

[Normal hematologic parameters].

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.

[Comparative study of the lepromin reaction performed on medical students and on a control group].

The lepromin test was studied in 64 medical students and in a control group consisted of 40 patients from the orthopedic clinic. Both groups matched with respect to age and sex, but differed with regard to socio-economical conditions. The Fernandez reaction showed low frequency of positive results in both groups: 10% in the first group and 5,6% in the second one.

[Comparative study of the intradermal reaction performed with whole lepromin and ultrasonic-treated lepromin in normal subjects].

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.