Erythrocyte velocity measurement in microvessels by a two-slit photometric method.

H Wayland, PC Johnson - Journal of applied physiology, 1967 - journals.physiology.org
H Wayland, PC Johnson
Journal of applied physiology, 1967journals.physiology.org
In both studies we have used the mesentery of the isolated cat intestine, mounted on a
microscope stage, as the preparation in which the microcirculation was studied. The
preparation is essentially similar to that used by one of us (6) in pressure-flow studies of the
intestine, with appropriate modifications for microscopic study. The mesentery is spread out
on the stage to give a clear view of the microvessels in that area. In our application, the field
was illuminated with a highpressure mercury arc filtered by an absorption filter with a peak …
In both studies we have used the mesentery of the isolated cat intestine, mounted on a microscope stage, as the preparation in which the microcirculation was studied. The preparation is essentially similar to that used by one of us (6) in pressure-flow studies of the intestine, with appropriate modifications for microscopic study. The mesentery is spread out on the stage to give a clear view of the microvessels in that area. In our application, the field was illuminated with a highpressure mercury arc filtered by an absorption filter with a peak transmission at 4,230 A, which is close to the peak in the absorption of hemoglobin at about 4, I 50 A. Correlation method. In these studies, the image of the mesenteric vessel to bc studied is projected onto an adjacent screen situated about I 2-18 inches from the microscope(Fig. I). An objective lens of 20 X and 0.60 NA is used with an eyepiece of 5 X or I o X. The screen is penetrated by two parallel slits several millimeters apart, each of which is connected to a photomultiplier tube by means of a light pipe. The image of the vessel is oriented perpendicular to the slits. Depending upon the magnification and screen distance, the equivalent slit separation is 45 to 70 p (referred to the microcirculation). The photomultiplier signals caused by passage of the erythrocyte image across the two slits are recorded on magnetic tape. The similarity of upstream and downstream signal patterns from a capillary is shown in Fig. 2 (middle panel). Also shown are signal patterns from an arteriole and a venule. By measuring the effective slit separation and the time shift required to
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