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Biomedical subjects

M Petitjean

Publications and source records attributed to M Petitjean.

23 records · Page 2Linked to original sources
PubMed1990

Phonomyogram and electromyogram relationships with isometric force reinvestigated in man.

Contracting muscle generates sounds which can be recorded easily by means of a microphone. To determine if a phomomyogram (PMG) can be used to monitor muscle force, a comparison was made between simultaneous recordings of PMG and monopolar electromyogram (EMG) from the isometrically contracting biceps brachii muscle and the external flexion force. Locations of the monopolar electrode and microphone were identified in relation to the motor point. Whatever the recording site, PMG amplitude was proportional to EMG amplitude and both showed a quadratic relationship to muscle force. Changes in the PMG spectrum with force were similar to those in EMG, i.e. the mean power frequency increased up to about 30% maximal voluntary contraction and then reached a plateau. Despite a slightly higher variability, PMG was shown to be a valid index of muscular isometric force. At the same force, the amplitude of both PMG and EMG was lower in the prone than in the supine position of the hand. This result indicated a selective recording of biceps brachii muscle activity.

Adult↗
PubMed1990

Epidermal growth factor binding and action on tympanic membranes.

A significant percentage of tympanic membrane (TM) perforations require some form of therapy to heal. Topical application of epidermal growth factor (EGF), a potent mitogen for epidermal and mesodermal cells, promotes healing of injuries in tissues histologically similar to TM, such as cornea and skin. We evaluated TM as a target tissue for EGF action. Specific, high affinity receptors for EGF were detected in TM (Kd = 3.1 nM, 150 fmol receptor/mg protein). Autoradiography of iodine 125-EGF binding to intact TMs revealed that EGF receptors were present on cells in the stratified squamous epithelial layer and in the stromal/mucoepithelial layer. Repetitive treatment of perforated cat TMs with 20 micrograms of EGF formulated in saline induced substantial hyperplasia of epithelial and stromal layers compared to paired TMs treated with saline. A single treatment of perforated cat TMs with 50 micrograms of EGF formulated in a hydrogel or in shredded Gelfoam produced significantly (p less than .05) smaller perforations at 6 days following the operation compared to paired TMs treated with vehicles. These results demonstrate that TM is a target tissue for EGF and that topical treatment with EGF stimulates healing of TM perforations.

Animals↗
PubMed1981

Comparative study of some characteristics of the semen of RR (rose comb) or rr (single comb) cockerels.

Comparative studies were made of semen samples from subfertile RR and normally fertile rr cockerels. These samples were obtained either by abdominal massage or directly from the tip of papillae. The numbers of collected sperm did not differ between genotypes and the sperm from RR cockerels were less motile than those from rr cockerels irrespective of the semen collection method. The uric acid concentration of seminal plasma was influenced by the semen collection method (massage greater than papillae) but no variations were induced by the genotypes. The ATP-ase and acid phosphatase activities found in the seminal plasma were influenced respectively by the genotype (rr greater than RR) and the semen collection method (papillae greater than massage). The fumarase and acrosin activities found in the sperm were not influenced by the semen collection methods while acrosin activity was found to be higher in RR than in rr cockerels. Correlations between these various characteristics are given in detail.

Acid Phosphatase↗