[Structure-function relationship in the membrane demonstrated by deuteration].
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Animals↗
Biomedical subjects
V Vasilescu
Publications and source records attributed to V Vasilescu.
Abolishment of the Ranvier node excitability under quasi-total deuteration and rhythmic stimulation.
The isolated nerve fibre, when quasi-totally deuterated, loses its excitability after about 15' of rhythmic stimulation at frequencies of 150-200 Hz. It is only on internal rehydration that excitability is recovered at high frequencies of stimulation. An excitation-energy coupling is suggested to exist, which appears to be more obvious at high frequencies of stimulation and strongly affected by the proton-deuteron exchange in the intracellular medium.
Action Potentials↗
[Electrical response latency of the retina in the frog under different experimental conditions].
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Animals↗
New data concerning the role of water in biosystems.
Data concerning the state and role of water (H2O) in the nerve, muscle and retina, obtained by the deuteriation technique, nuclear magnetic resonance (NMR) spectrometry and freeze-drying are reported. The existence of at least three distinct tissue water compartments is disclosed, whose sizes depend on the nature and state of the tissue. Some of these water populations appear to be indispensable to keeping up both the (supra) molecular architecture and the function of the system, while others have only a role in securing normal functioning. The mechanisms of the anesthetic action are also discussed and water involvement in this process is pointed out. Heavy water (D2O) effects on the cellular energy mechanisms are critically analysed. A change in the hydration degree of various species and the stabilization of the native conformation of biopolymers, as possible causes of heavy water effects, are remarked.
Animals↗
Study of sodium and potassium intake in different categories of healthy subjects.
The usual Na+ and K+ intake was investigated in 436 apparently healthy subjects, 370 men and 66 women, ranging in age from 19 to 56 years, distributed into three lots: 219 from a metallurgical plant, 100 from a military unit and 117 from an unselected population sample. The average Na+ intake amounted to 214 mEq/24 h in the first lot of study, to 224 mEq/24 h in the second and to 203 mEq/24 h in the third, the differences among them being not significant. K+ intake in the three lots was 38 mEq/24 h, 43 mEq/24 h and 49 mEq/24 h, respectively. Na+/K+ ratio reached 5.6 in lot I, 5.2 in lot II and 4.1 in lot III, compared to the unitary ratio in natural foodstuffs. The data obtained demonstrate that Na+ intake in the general population is excessive, while K+ intake is deficient. It is assumed that this might partly account for the great incidence of arterial hypertension.
Adult↗
2H2O effects on ATP pool in frog stimulated nerve.
On stimulation a decrease of ATP pool was observed in the nerve immersed in 2H2O as compared to that of the nerve in H2O. Among the phenomena possible to account for this decrease, we are tempted to attach weight to the transfer rate of protons which finds expression in an increased raising time of the action potential, a stage in which the energy system is stressed.
Adenosine Triphosphate↗