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Biomedical subjects

M F Pedersen

Publications and source records attributed to M F Pedersen.

14 recordsLinked to original sources
PubMed1993

A longitudinal pilot study on phonetograms/voice profiles in pre-pubertal choir boys.

The phonetogram or voice profile, measuring frequency combined with intensity of the voice, has replaced simple measurement of tone ranges for analysis of professional boys choirs. Knowledge of the relationship between pubertal, sex hormones, and phonetogram development has been established in stratified studies. The connection between the singing voice in puberty and other pubertal phenomena needs documentation in longitudinal studies also. Therefore, a pilot study was carried out, where three boys aged 13-15 years were analysed at intervals of 2 months. Measurement of phonetograms, free and total serum testosterone and sex hormone binding globulin (SHBG) showed a significant relationship between SHBG and lowering of the lowest tones in the phonetograms (P < 0.01) confirming earlier stratified studies.

Adolescent↗
PubMed1990

Fundamental voice frequency in female puberty measured with electroglottography during continuous speech as a secondary sex characteristic. A comparison between voice, pubertal stages, oestrogens and androgens.

The change of fundamental voice frequency in continuous speech in female puberty was analysed in 47 girls by comparison of 2000 consecutive electroglottographic cycles in a reading situation. The results were compared with serum concentrations of androgens (dihydroepiandrosterone, delta-4-androstenedione, testosterone, and sex hormone binding globulin), oestrogens (oestradiol, oestrone, and oestronesulphate), and somatic puberty (weight, height, mamma stages, and pubic hair stages). Fundamental frequency in continuous speech was related only to oestrone r = -0.34, (P less than 0.05). But the tone range in continuous speech and the lowest tone in the phonetogram were found to be significantly correlated with many of the pubertal and hormone parameters. All these correlations could be explained by a common age-dependency. By multiple regression analysis different sets of variables for prediction of speaking fundamental frequency were found before and after menarche.

Adolescent↗
PubMed1989

Maxisorp RAST. A sensitive method for detection of antigen-specific human IgE in culture fluids.

For determination of allergen-specific IgE in cell culture supernatants and other highly diluted IgE preparations a radioallergosorbent test (RAST) based on high adsorption polystyrene test tubes has been developed ("Maxisorp RAST"). Cladosporium herbarum extract was used as a model allergen but timothy grass pollen, house dust mite and dog dander showed similar results. The test showed specificities of both allergen and immunoglobulin isotype and significant correlations (r = 0.67-0.88) with established RAST procedures were found. Based on immunosorbent-purified allergen-specific IgE the estimated sensitivity was within the order of 150-300 pg allergen-specific IgE per ml. The within-assay variation was 4-9% and the inter-assay-variation 17-29%. The Maxisorp RAST is useful as an inhibition assay for quantitating allergenic activity down to 0.1 biological units/ml of allergen extracts.

Allergens↗
PubMed1986

Fundamental voice frequency measured by electroglottography during continuous speech. A new exact secondary sex characteristic in boys in puberty.

The variation of fundamental voice frequency measured by the average of 2000 consecutive electroglottographic cycles in a reading situation has been examined in relation to pubertal development and androgens. Fundamental frequency among other parameters was related to height (r -0.82), pubic hair stage (r -0.87), testis volume (r -0.78), total testosterone (r -0.73) and serum hormone binding globulin (r 0.75). Single observations of fundamental frequency show a clear grouping of results under and over 200 Hz. Fundamental frequency of more than 200 Hz and serum testosterone of more than 10 nmol/l probably represent values for a boy in puberty. There seem to be comparable relations with other androgens and with serum hormone binding globulin.

Adolescent↗