Preparation of Red Blood Cell Column for Capillary Electrochromatography

Previous studies in skeletal muscle of the dog and cat have shown that venous vascular resistance changes inversely with blood flow and may be due mainly to red blood cell aggregation, a phenomenon present in these species. To determine whether red blood cell axial migration and sedimentation contribute to this effect, we viewed either vertically or horizontally oriented venules of the rat spinotrapezius muscle with a horizontally oriented microscope during acute arterial pressure reduction. With normal (nonaggregating) rat blood, reduction of arterial pressure did not significantly change the relative diameter of the red blood cell column with respect to the venular wall. After induction of red blood cell aggregation in the rat by infusion of Dextran 500, red blood cell column diameter decreased up to 35% at low pseudoshear rates (below ∼5 s−1); the magnitude was independent of venular orientation. In vertically oriented venules, the plasma layer was symmetrical, whereas in horizontally oriented venules, the plasma layer formed near the upper wall. We conclude that, although red blood cell axial migration and sedimentation develop in vivo, they occur only for larger flow reductions than are needed to elicit changes in venous resistance.

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Rapid Patient-Side Evaluation of Endothelial Glycocalyx Thickness in Healthy Sedated Cats Using GlycoCheck® Software

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.727063 ◽

2022 ◽

Vol 8 ◽

Author(s):

Ivayla D. Yozova ◽

Leonel A. Londoño ◽

Kristina K. Millar ◽

Hiroki Sano ◽

Karin Weidgraaf ◽

...

Keyword(s):

Blood Cell ◽

Lower Limit ◽

Red Blood Cell ◽

Dark Field ◽

Vessel Density ◽

Endothelial Glycocalyx ◽

Cell Column ◽

Sidestream Dark Field ◽

Upper Limit ◽

Patient Side

The endothelial glycocalyx (EG) determines transvascular fluid fluxes, and influences inflammation, coagulation, and capillary blood flow. The GlycoCheck® software calculates EG thickness using sidestream dark field videomicroscopy recordings. This method has not been evaluated for use in cats. The aim of the present study was to evaluate the use of GlycoCheck® for estimating EG thickness in healthy cats, and to investigate the variability of EG thickness in this population. One hundred and one healthy research-purposed cats were included in the study. The cats were sedated, and a handheld videomicroscope, connected to GlycoCheck® software, was used to evaluate the sublingual microvasculature. The parameters measured included perfused boundary region (PBR, an indirect measurement of EG thickness) in vessels between 5 and 25 μm in diameter, valid vessel density, percentage red blood cell filling, and median red blood cell column width. Heart rate, respiratory rate, pulse oximetry and oscillometric blood pressure readings were also recorded. There were 35 neutered male cats, 11 intact males, 38 neutered females, and 17 intact females. The average age was 63 months (range, 11–160 months). Tolerance intervals for PBR (vessel diameter 5–25 μm) were 1.89–3.00 μm (95% CI, lower limit 1.76–2.04, upper limit 2.83–3.13 μm); for valid vessel density were 73.33–333.33 μm/mm2 (95% CI, lower limit 77.00–99.33, upper limit 312.67–350.33 μm/mm2); for percentage red blood cell filling were 59.85–85.07% (95% CI, lower limit 58.97–63.33, upper limit 83.07–88.20 %); and for median red blood cell column width were 5.63–8.59 μm (95% CI, lower limit 5.28–6.07, upper limit 8.14–9.51 μm). There was a negative association between median red blood cell column width and body weight (p = 0.007). The median red blood cell column was significantly wider in intact females when compared to spayed females (p = 0.033). The GlycoCheck® analysis was easily performed in healthy sedated cats. Clinical variables did not have an effect on the EG thickness. These results suggest that this technique could be valuable for evaluation of the EG and microvascular parameters in cats.

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