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Biomedical subjects

M Lazăr

Publications and source records attributed to M Lazăr.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

Electrical activity induced by ischemia in the skeletal muscle of patients with spasmophilia.

The incidence of spontaneous electrical activity during ischemia was studied in normal and spasmophilic subjects with a Bronk electrode inserted in the first dorsal interosseous muscle. Subjects were of both sexes, aged 16 to 65 years. The diagnosis of spasmophilia was established electromyographically by a variant of the Alajouanine test. Ischemia induced in many cases an electrical activity consisting of discharge potentials that have the amplitude, duration and morphology of motor unit potentials. The number of discharging motor units varied, sometimes leading to an electrical Trousseau associated to a carpal spasm. The discharge of individual motor units was irregular and practically uninfluenced by passive manipulations on the muscle or voluntary contraction. The activity started usually 30 sec to 1 min after the onset of ischemia, reached a maximal intensity (as to the number of motor units and frequency of discharge) in about 1 min and declined gradually in the following minutes. This activity was encountered in 55.06% of 770 cases of spasmophilia and only in 11.66% of 283 normal subjects, with a tendency to more intense discharge in spasmophilia. Its incidence in the spasmophilic group was closely related to the intensity of spontaneous repetitive discharges appearing electromyographically after the activation test, reaching 78.63% in most severe cases. The behaviour was interpreted as indicating a higher susceptibility in spasmophilia of axons to depolarization induced by hypoxia. This higher susceptibility appears as an important component of the excitability alterations leading to the complex neuromuscular disorders occurring in spasmophilia.

Adolescent↗
PubMedDate not supplied

EEG automatic processing method.

This is a description of researches carried out in man and experimentally in rats. The results - obtained in 44 children aged between 12 and 14 yr. - of the electric signal processed as a F/A ratio were compared to the transport mechanisms of the blood sodium. We found that the normal brain excitability level was consistent only with the blood sodium transport through interaction with the proteins. The lack of such interaction was accompanied by an increased excitability on eeg recordings and by behaviour disturbances. The researches carried out in rats had in view the brain excitability level in two groups of animals aged 6-8 months, which drank from their birth either physiological salt (group 1) or distilled water (group 2). In this species, in spite of direct visible modifications in eeg recordings by sensorial stimulation, the processing as F/A ratio did not show any differences, and this made necessary the use of computers to process rightly the data; the respective digitization and memorising methods are described, too.

Adolescent↗
PubMedDate not supplied

Systolic time intervals after a seven-day orbital flight.

Heart rate (HR), systolic time intervals (STI) (pre-ejection period--PEP, left ventricular ejection time--LVET, PEP/LVET ratio indirect ejection fraction--EF, stroke volume--SV and QT interval of two cosmonauts (Leonid Popov--LP and Dumitru Prunariu--DP), were studied before, during and after an ergometric bicyle exercise test performed before and after the seven-day Soviet-Romanian orbital flight on the Soyuz 40--Saliut 6 Complex in May 1981. To this purpose one precordial electrocardiogram (Ecg) and the ear densitogram (Den) were recorded simultaneously. The method used permitted clear recordings even during exercise. Ecg and Den signals were stored on magnetic tape, processed in an analogue device and in a digital computer. The data obtained after landing suggest a slight cardiac deconditioning in LP, demonstrated especially by PEP augmentation, which was unchanged in DP corresponding to a better cardiac contractility. It is concluded that the seven-day orbital flight has not produced important cardiovascular alteration.

Adult↗