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Biomedical subjects

M Intaglietta

Publications and source records attributed to M Intaglietta.

At least 145 records · Page 8Linked to original sources
PubMed1976

The measurement of pressure and flow in the microcirculation: application to physiological and clinical problems.

The analysis of hemodynamic phenomena at the level of microscopic blood vessels of diameters ranging from 10(-2)-10(-3) cm is currently based on direct measurements of plasma pressure and red blood cell velocity in in-vivo conditions. Pressure measurements are performed with active pressure measurement systems via cannulae with 1 mum tip openings. Flow measurements are deduced from optical transit time methods from data recorded by television. The technique provides both average and dynamic data. The latter is derived from signal processing of the direct measurements by means of active filters. These techniques yield data on low level signals related to the periodic action of the heart. This analysis provides information on the transit time of pressure and flow pulses through the microcirculation. These methods are currently utilized in routine physiologic investigations and as a means for studying the human skin microcirculation of normal subjects.

Animals↗
PubMed1976

Contributions of pressure and flow sensitivity to autoregulation in mesenteric arterioles.

The relative influence of presence and flow on dilation of arterioles with pressure reduction was examined in preparations of cat mesentery. Erythrocyte velocity and diameter were measured in individual arterioles during stepwise reduction in mesenteric arterial pressure. Volume flow was calculated from velocity and diameter data. Approximately half of the arterioles which dilated with pressure reduction also showed an increase in volume flow. In a second series of experiments, a graded reduction of flow in single arterioles was produced by local downstream occlusion. Graded occlusion caused dilation. In a third series, flow in single arterioles was completely stopped by downstream occlusion, and arterial pressure was then lowered. Most arterioles dilated with pressure reduction. In a fourth series, flow in the total preparation was completely stopped and static intravascular pressure set by a reservoir. Elevation of static pressure typically produced arteriolar constriction. We conclude from these studies that the mesenteric arteriole is sensitive both to intravascular pressure and flow, with the former probably more important than the latter in the phenomenon of autoregulation.

Animals↗
PubMed1975

Measurements of blood flow velocity in the microcirculation.

A method for the measurement of red blood cell velocity in the microcirculation is described. The technique is based on the on-line cross-correlation of the delay between optical signatures derived from photodetectors aligned in direction oflow. A specialised photodiode holder which can be inserted directly in place of an ocular is described. The interdetector delay data is computed automatically from the cross-correlation function by a peak detector designed to provide a voltage proportional to the delay to maximum cross-correlation, regardless of intermediate lower peaks. Application of this system to measurements in the rabbit ear chamber, mesentery and skeletal muscle is described.

Blood Flow Velocity↗