Radial distribution of white cells during blood flow in small tubes.

The radial distribution of white blood cells (WBC) in blood flowing through glass tubes (i.d. 69 micron) was studied as a function of wall shear stress (range 0.

Microphotometric determination of hematocrit in small vessels.

Evaluation and calibration of a microphotometric method for hematocrit determination in microvessels of transilluminated tissues is described. This method is based on the relation of the optical density (OD) of a microvessel to its hematocrit (Hct). The following requirements of the microphotometric system appear essential: narrow-band monochromatic light source with efficient false light suppression, high numerical aperture of the objective and low numerical aperture of the condensor.

Analysis of the hematocrit distribution in the mesenteric microcirculation.

The hematocrit in the microcirculation of the rat's mesentery was determined either by using measurements of optical density (in 56 arterioles and 52 venules) or by counting the number of red cells per unit vessel length (in 63 capillaries) from photographs. The systemic hematocrit (Hsys) averaged 0.42 +/- 0.

Model experiments on the effect of bifurcations on capillary blood flow and oxygen transport.

O2-delivery by a single capillary is a function of the flow rate and the fraction of flow made up of red blood cells. Capillary flow rate in turn depends upon flow resistance which is determined by the fraction of capillary volume occupied by red blood cells. Experiments were carried out to study the relationship between these parameters in an in vitro model consisting of glass capillaries (I.