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Biomedical subjects

L L Shik

Publications and source records attributed to L L Shik.

At least 19 recordsLinked to original sources
PubMed1990

[Initial expiratory activity as one of the criteria of the respiratory center function].

In 13 healthy men at rest and dosed muscular loads the authors studied maximal rates of the mouth pressure at the onset of inhalation and expiration (dP/dtI, dP/dtE) as well as the respiratory pattern. The parameter dP/dtE positively correlated with that of dP/dtI which reflects, as is known, an inspiratory activity of the respiratory center. The authors think that dP/dtE parameter can be used for noninvasive determination of expiratory activity.

Adult↗
PubMed1985

[Regulation of respiration during muscular exertion].

A brief critical review of literature shows that many authors still follow a classical theory that the respiration control is performed by feedback (by deviation of PCO2, PO2 and pH in blood). This point of view does not account for the exercise hyperpnea. The present paper contains the various data and considerations which show that respiration during muscular exercise is controlled by a combined self-learning system. The system is based on both disturbance (open-loop) control and feedback control. The signals of disturbance (of central origin and from receptors of exercising muscles) cause the increase of respiration during exercise. The signals of deviations (from peripheral and central chemoreceptors) correct the response of respiratory centre to disturbance signals. The self-learning takes place by the formation of conditioned reflexes that ensures the control of respiration (the stability of gaseous composition of blood during exercise).

Animals↗
PubMed1980

[Quantitative analysis of the relationship between arterialization of blood and irregularities of ventilation--perfusion ratios].

Comparative data on the quantitative analysis of the relationship between arterialization and irregularity of the ventilation perfusion ratios are presented for a simple two-component lung model and for a model with a logarithmically normal distribution of VA/Q. A possibility of respiratory failure existence without material shifts in the arterial blood gas composition is substantiated.

Humans↗
PubMed1979

[Role of increased peripheral vascular resistance in burn shock].

The effect of lethal burn injury on the parameters of hemodynamics and respiration was investigated in intact rabbits and those with disconnected aortal and sinocarotid reflexogenic zones. The rabbits of both groups demonstrated similar changes in cardiac output and total oxygen consumption. Unlike intact animals, the burn in rabbits with disconnected reflexogenic zones did not lead to a marked increase in the peripheral vascular resistance. Accordingly, the systemic arterial blood pressure in them fell to a considerably greater extent than that in the intact animals. The life span of the rabbits exposed to burns was less as compared to the intact ones. A reflex compensatory nature of the increased peripheral vascular resistance in burn shock is suggested.

Animals↗
PubMed1979

[Non-uniformity of the ventilation-perfusion ratio in the lungs, and arterial hypoxemia].

The general analysis of the relationships between the extent of nonuniformity of ventilation-perfusion ratios and blood flow through poorly ventilated protions of the lungs on the one hand and arterial hypoxemia on the other one has been performed. Quantitative evidence on the onset of arterial hypoxemia in disturbances of ventilation-perfusion ratios are obtained.

Humans↗