Myocardial Capillary Flow Pattern as Determined by the Method of Coloured Microspheres

Reeves, Wyatt; Rakusan, K

doi:10.1007/978-1-4615-9510-6_53

Cited by 5 publications

(2 citation statements)

References 11 publications

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“…The probability distributions constructed from the IDMI data were therefore a little narrower than those of the microspheres, but now require consideration in assessing sources of variation. Reeves and Rakusan (1988) provided data showing that micro spheres do not block capillaries. They used colored microspheres to show the direction of flow in myocardial capillaries.…”

Section: Discussionmentioning

confidence: 99%

Temporal fluctuations in regional myocardial flows

King

Bassingthwaighte

1989

Pflugers Arch.

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Considerable spatial heterogeneity has been observed in regional myocardial blood flow in isolated hearts and in both anesthetized and conscious animals. In order to study how local blood flow varies with time, the data obtained by King et al. (1985) from ten awake, healthy baboons were analyzed to estimate the role of temporal fluctuations. Four to six distributions of regional flows were estimated at intervals of 4 min to 27 h, using 15 μ diameter microspheres and dividing each heart into 204 locatable pieces (average piece mass = 0.17 g). The technique averages over the 40 s of the injection giving no measure of fluctuations over a few seconds. The temporal variation in regional blood flow, expressed as the relative dispersion (SD/mean) of the temporally separated measurements about the mean flow for each piece and corrected for methodological noise, was 12% for the whole heart (10828 observations). For the left ventricle, the temporal variation was 10% (8806 observations), for the right ventricle 14% (1455 observations), and for the atria 22% (567 observations). On a relative basis, temporal fluctuation was greatest in regions having low flows. Since the magnitude of the changes in flow distributions was the same after 4 min as it was in several hours, we conclude that much of the "twinkling" is a high frequency phenomenon occurring over seconds to a few minutes. Further, it is concluded that regional myocardial blood flow in conscious primates is relatively stable with time, temporal fluctuations causing only about one third of the variation between regions.

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Section: Discussionmentioning

confidence: 99%

Temporal fluctuations in regional myocardial flows

King

Bassingthwaighte

1989

Pflugers Arch.

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“…Distributions of capillary length, density, and blood flow, and of red blood cell (RBC) flow path lengths and transit times have been reported for various skeletal muscles (Egginton et al, 1987;Honig et al, 1977; Honig and Odoroff, 1981;Sarelius, 1986). Moreover, directions of flow and staggering of capillaries in heart muscle have been investigated (Reeves and Rakusan, 1987).…”

Section: Introductionmentioning

confidence: 99%

A versatile model of steady state O2 supply to tissue. Application to skeletal muscle

Groebe

1990

Biophysical Journal

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A model of combined convective and diffusive O2 transport to tissue is suggested which allows for the calculation of PO2 distributions in a cuboid tissue region with arbitrary microvascular geometries and blood flows. Carrier-facilitated O2 diffusion in the erythrocytes and in the tissue and red blood cell reaction kinetics are considered. The model is based on analytical descriptions of the PO2 fields of single erythrocytes surrounded by carrier-free layers in an infinite three-dimensional space containing an O2 carrier such as myoglobin. These PO2 fields are overlaid to obtain a solution of the differential equation of diffusion in respiring tissue. The model has been applied to a situation in heavily working skeletal muscle. Resulting PO2 profiles exhibit steep peri-capillary PO2 gradients. Further into the fiber, the profiles are essentially flat at low PO2 levels in good agreement with experimental findings (Gayeski and Honig. 1986. Am. J. Physiol. 251:H789-H799). PO2 dependence of facilitation of O2 transport produces a "layer deficient of functional carrier" which extends into the muscle fiber and which represents a reserve of O2 conductance automatically recruited in exercise. Furthermore, it results in a homogenization of red blood cell O2 fluxes which accounts for the absence of PO2 gradients along the muscle fiber axis (cf. Gayeski and Honig. 1988. Am. J. Physiol. 254: H1179-H1186).

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