The effect of anemia on the coronary microcirculation was studied in young male rats. Chronic anemia resulted in increased left ventricular end-diastolic pressure and decreased functional reserve. Cardiac mass in anemic animals increased by 25%. Capillary and arteriolar densities in these hearts remained unchanged, indicating angiogenesis in this experimental situation (estimated aggregate capi...

The 'cost of reproduction' (i.e. the trade-off between current reproduction and future fecundity and/or survival) is a central concept in life history theory, yet we still know very little about the physiological mechanisms underlying such costs. Recently it has been recognized that reproduction itself or the regulatory (hormonal) mechanisms underlying reproduction might result in 'costs' (cf. ...

Chronic hypoxia causes chronic mountain sickness through hypoxia-induced pulmonary hypertension (HPH) and increased hematocrit. Here, we investigated the impact of increased hematocrit and HPH on right ventricular (RV) afterload via pulmonary vascular impedance. Mice were exposed to chronic normobaric hypoxia (10% oxygen) for 10 (10H) or 21 days (21H). After baseline hemodynamic measurements, ∼...

The effects of hematocrit on renal hemodynamics and sodium excretion were studied in anesthetized dogs during both hydropenia and volume expansion. The hematocrit was decreased by isovolemic exchange with the animal's own previously harvested plasma and increased by isovolemic exchange with fresh, washed red blood cells. Renal perfusion pressure was maintained constant throughout the experiment...

This study describes the effect of a chronic decrease in hematocrit on blood pressure, cardiac output (CO), total peripheral resistance (TPR), and plasma volume in spontaneously hypertensive rats (SHR), and all but plasma volume in normotensive Wistar rats (NWR). Hematocrit was decreased by treatment with either heparin, vitamin K inhibitor ( pelentan ), or by repeated blood letting (BL). The r...

OBJECTIVE To determine whether phlebotomy contributes to changes in hemoglobin and hematocrit levels in hospitalized general internal medicine patients. DESIGN Retrospective cohort study. SETTING General internal medicine inpatient service at a tertiary care hospital. PARTICIPANTS All adult patients discharged from the Toronto General Hospital's internal medicine service between January 1...

BACKGROUND In a whole blood coagulation test, the concentration of any in vitro diagnostic agent in plasma is dependent on the hematocrit level but its impact on the test result is unknown. OBJECTIVE The aim of this work was to clarify the effects of reagent concentration, particularly Ca2+, and to find a method for hematocrit estimation compatible with the coagulation test. METHODS Whole b...