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Biomedical subjects

M Pierson

Publications and source records attributed to M Pierson.

At least 73 records · Page 4Linked to original sources
PubMed1980

Some dualistic properties of the cochlear microphonic.

Within a small frequency range just above the characteristic frequency of a differential electrode pair, cochlear microphonic input-output functions are bimodal, exhibiting two maxima. The more sensitive, low-intensity response has a more limited linear operating range, and it is more labile due to acoustic fatigue or hypoxia. After fatigue or hypoxia, the high-intensity response is revealed. The latter operates 180 degrees out-of-phase with the former, presumably due to its being generated more basalward in the cochlea. The difference in the lability of the two components suggests that the two sources are different types of hair cells: i.e., outer and inner hair cells.

Acoustic Stimulation↗
PubMed1980

Effect of modulation of basilar membrane position on the cochlear microphonic.

Certain characteristics of the extracellular cochlear microphonic (CM) recorded by intracochlear electrodes change in a bimodal manner as a function of prior acoustic exposure, intensity of stimulation, or stimulus frequency. In the present study, it is shown that biasing the basilar membrane position toward scala tympani serves to enhance the CM amplitude when the cochlea is unfatigued, when low-intensity stimuli are used, or when frequencies below the best frequency of a differential electrode pair are used. Conversely, after acoustic fatigue, or during high-intensity or high-frequency stimulation, the microphonic potential is enhanced by a movement of the basilar membrane toward the scala vestibuli. The two populations of hair cells, whose responses are enhanced and diminished on opposing positions of the basilar membrane, are probably outer and inner hair cells.

Acoustic Stimulation↗
PubMed1980

[Phenotype of a ring-chromosome 6 carrier. Clinical and cytogenetic study].

A ring 6 chromosome was detected in a 18 months old boy. The patient was a dwarf with psychomotor retardation, morphological anomalies i.e. microcephaly, bird head shaped facies with large ears, arched palate and micrognathia. A survey of 9 others cases collected in the medical literature permit to propose a specific phenotype for this chromosomal abnormality.

Chromosome Aberrations↗
PubMed1978

[Laron type familial dwarfism; genetic primary somatomedin deficiency].

Five children from 3 different families presented with severe dwarfism and the morphological and biological features described by Laron: familial occurrence, small stature, peculiar facies, high levels of plasma HGH and resistance to treatment by GH. This therapeutic inefficiency is expressed by an absence of physical growth and unchanged nitrogen balance, during a prolonged treatment. The plasma levels of somatomedine were very low (K. Hall's biological method) and not influenced by administration of exogenous HGH. These findings suggest that the fundamental disorder is not an abnormal structure of the molecules of GH. This hypothesis seems further confirmed by the structural analysis of plasma HGH, which gave the same results as those of the reference GH.

Child↗
PubMed1978

[Myxedema caused by ectopic lingual thyroid treated by autotransplantation. Results 18 years later].

An ectopic thyroïd gland causing hypothyroïdism was found in a 7 years old girl. The treatment was stopped six months later, nevertheless the growth rate was not affected. Sudden mechanical airway obstruction caused by the lingual goiter needed at the age of 16 years a surgical management. A thyröid nodule auto-transplantation was performed with a rather good success. Special comments about some physiopathological aspects of this original case.

Child↗