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Biomedical subjects

M F Tripşa

Publications and source records attributed to M F Tripşa.

5 recordsLinked to original sources
PubMedDate not supplied

Studies concerning ATP dynamics in essential hypertension.

The use of Beckmann LS-7000 liquid scintillation spectrometer enabled us to develop a rapid and reproducible technique for the enzymatic microdosage of ATP by means of the bioluminescence reaction of the luciferin-luciferase system from the firefly. Changes of ATP concentration in the plasma, erythrocytes and cerebrospinal fluid of the hypertensive subjects as compared to the control ones have been revealed by means of this method. According to our results ATP concentration significantly increases in the plasma and cerebrospinal fluid and slightly modifies in the erythrocytes of the hypertensive as compared with control subjects. Correlation of data concerning the variation of ATP distribution in the different compartments (plasma, erythrocytes, cerebrospinal fluid) with those related to Na and K content in hypertensive and control subjects seems to be useful for some remarks on the molecular mechanisms in the essential hypertension.

Adenosine Triphosphate↗
PubMedDate not supplied

Problems concerning the measurements of electrical events in myelinated nerve fibers.

As only the availability of strictly accurate data enables the realistic theoretical modelling of the ionic channel behaviour, the most important and topical problems concerning the measurements of the electrical events at the level of the myelinated nerve fiber are analysed. Thus, the following aspects are examined: (a) morphological characteristics of the myelinated nerve fiber and problems arising from the membrane currents measurements: (b) problems induced by use of the insulating layers on the myelin surface: air gap or vaseline seal insulation; (c) effect of the nodal gap resistance on the ionic currents measurements in the node of Ranvier membrane.

Animals↗
PubMedDate not supplied

Erythrocyte molecular shape modifications in the primary hypertension.

During the last 15 years an increasing experimental support for the hypothesis of the involvement of the cell membrane alterations in the pathogenesis of the essential hypertension has been evidentiated. Four key factors have been revealed as involved in the generation of sodium-dependent hypertension: 1) genetic or acquired defect in renal sodium excretion; 2) dietary sodium intake; 3) natriuretic hormone as sodium inhibitor; 4) sodium for calcium exchange in smooth muscle and plasma membranes. Taking into account the fact that all of them could be responsible for the cell shape modifications at molecular level and considering also the fact that the membrane defects are present only in the primary forms of hypertension, a comparative study of erythrocyte shape modifications between control and hypertensive human subjects has been performed. The shapes of cells were investigated by an inverted light microscope after their sedimentation on glass cover slips. The computer analysis of images revealed a significant difference (p less than 0.001) between the control and hypertensive subjects as concern the echinocytes/total cells ratios, concluding that a shape modification of erythrocytes is occurring in case of essential hypertension. The high rate of transformation of biconcave disks into echinocytes found in case of hypertension is correlated with ATP pool decreasing that we have previously observed at the same disease. The results are discussed in terms of molecular membrane properties of the mammalian erythrocytes and their structure proteins/lipids organization. A model of cell shape transformation upon ATP pool control is presented for the hypertensive disease.

Adenosine Triphosphate↗
PubMedDate not supplied

The structure-function relationships in the ionic channels of the axonal membranes as revealed by deuteration.

The present study has two purposes: c) to summarize our most important experimental results concerning the deuteration effects on the Ranvier node membrane as well as those obtained by others on the giant axons; ii) to reveal the significance of the macroscopic-microscopic correlations reflected in the excitation processes which underlie the ionic channel behaviour and for which deuteration has provided a new alternative of investigating the molecular mechanisms.

Animals↗