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Biomedical subjects

V Ionescu

Publications and source records attributed to V Ionescu.

At least 19 recordsLinked to original sources
PubMed1982

The influence of day and night work on the circadian variations of cardiovascular performance.

Circadian variations of the pre-ejection period, Q-T interval, heart rate and oral temperature at rest and in day and night shift work were investigated. At rest, pronounced circadian variation was found in heart rate, pre-ejection period and Q-T interval. The ratio between Q-T interval and heart rate also shows a distinct circadian variation. When working, the rest rhythms of the variables were obscured. The physiological implications for shift work are discussed.

Adolescent↗
PubMed1978

A method for continuous electrocardiodynamic monitoring.

A new method is presented for the monitoring of cardiac time intervals, e.g. in clinical and industrial work investigation. The methods yields 'on-line' the electrocardiodynamic time profile during rest as well as effort, and has applications in health care, sports and occupational medicine. By means of analog processing of an electrocardiographic signal, ear densitogram and beat-by-beat display of the measured cardiac time intervals as amplitude-modulated pulses, an 'electrocardiodynamic time profile' is obtained. In order to estimate the accuracy and the limitations of the method, a comparison with computerized methods was performed. In an ergonomic experiment carried out by a Romanian-Swedish research team, analog and digital methods for the detection of cardiac time intervals showed good agreement.

Adolescent↗
PubMed1977

Focal abnormalities in mitochondrial distribution in muscle. Two atypical cases of so-called "central core disease".

Describing two new cases of so-called Central Core Disease, the authors revealed certain atypical features: The cores were formed in central as well as in peripheral position; they were observed in some apparently type II fibers; typical "structured" and "unstructured" cores coexisted with "reversed" core. Starting from this pictures a cycle of core formation was imaginated supposing to be initiated as the consequence of abnormal functional interrelationship between muscular and neural components in early myogenesis.

Adult↗
PubMed1977

Myotubular (centronuclear) (neuro-)myopathy. I. Clinical, genetical and morphological studies.

Five new cases of myotubular (centronuclear) (neuro-)myopathy are presented. Myometric studies revealed type I fibre atrophy and mispositioned nuclei, at various stages between the myotubular structure and the normal subsarcolemmic position. Certain morphological changes, for instance target structures, suggest denervation involving the fibres in an early stage of myogenesis; differentiation seems to be more affected than growth. The genetic defect has an autosomal recessive mode of inheritance with penetrance and degree of expressivity varying from one case to another in the three families.

Adult↗
PubMed1975

Duchenne muscular dystrophy and poliomyelitis. A study of dystrophic-denervated muscle.

A systematic study of dystrophy-denervation in human muscle showed minimal morphometabolic differences between dystrophic and dystrophic-denervated muscle. The only certain conclusion is that denervation influences the rhythm of evolution of the dystrophy without impressing any of the few characteristics considered at present as peculiar to denervation.

Child↗
PubMed1975

Identification of Duchenne muscular dystrophy carriers. Electron microscopical investigation of skeletal muscle.

In order to identify a subclinical dystrophy, muscle biopsy specimens from 15 mothers of boys with Duchenne muscular dystrophy were studied by electron microscopy. Genetic investigations and biochemical determinations were not conclusive for a diagnosis of the carrier state. The fine structural lesions were sufficient to vertify the diagnosis of a subclinical dystrophy, and our findings were in agreement with other investigators. However, original intranuclear filamentous formations were noted in one case.

Adult↗
PubMed1975

Potassium and sodium ions in the glycerinated skeletal muscle. Distribution changes induced by adenosine triphosphate and nondissociable anesthetic substances.

Investigation of the ionic behavior of glycerinated muscle fibers showed that the residual structures of this biologic cellular material, lacking functional membranes, are able to discriminate between alkaline ions. The characteristics of the ionic selectivity of the glycerinated fibers change with their functional state and with the presence in the medium of certain nonionic substances. Among the more important features of ionic distribution between the membrane-free fibers and the medium are the following: (1) There is evident adsorption of potassium on the fibers, in the absence of ATP. (2) This adsorption increases in contraction and decreases in relaxation. (3) At high ionic concentrations, in contrast to what occurs at low potassium concentrations, the glycerinated muscle prefers sodium to potassium, but even under these conditions both ions are accumulated in the fibers to far greater levels than in the medium. This strongly suggests a Donnan ionic equilibrium developing parallel to the adsorption process. (4) Nonionic substances of the general anesthetic group markedly alter the ionic selectivity of the glycerinated fibers, probably by their action on the water's physical state. A mechanism is proposed for the observed ionic adsorption specific of the muscle-a mechanism in which actin-myosin coupling plays the cardinal adsorption role. In the general interpretation of the data a synthetic concept is advanced according to which an entire set of processes and factors concurs with the distribution of ions between the muscle and the medium.

Adenosine Triphosphate↗