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At least 19 recordsLinked to original sources
PubMed1996

Altitude acclimatization and blood volume: effects of exogenous erythrocyte volume expansion.

We studied sea-level residents during 13 days of altitude acclimatization to determine 1) altitude acclimatization effects on erythrocyte volume and plasma volume, 2) if exogenous erythrocyte volume expansion alters subsequent erythrocyte volume and plasma volume adaptations, 3) if an increased blood oxygen content alters erythropoietin responses during altitude acclimatization, and 4) mechanisms responsible for plasma loss at altitude. Sixteen healthy men had a series of hematologic measurements made at sea level, on the first and ninth days of altitude (4,300 m) residence, and after returning to sea level. Twenty-four hours before the ascent to altitude, one group received a 700-ml infusion of autologous erythrocytes (42% hematocrit), whereas the other group received only a saline infusion. Erythrocyte infusion increased erythrocyte volume by approximately 10%, whereas saline infusion had no effect; in addition, initially at altitude, blood oxygen content was 8% higher in erythrocyte-infused than in saline-infused subjects. The new findings regarding altitude acclimatization are summarized as follows: 1) erythrocyte volume does not change during the first 13 days and is not affected by prior exogenous expansion, 2) a modest increase in blood oxygen content does not modify erythropoietin responses, 3) plasma losses are related to vascular protein losses, and 4) exogenous erythrocyte volume expansion coincides with transient increases in plasma loss, vascular protein loss, and mean arterial pressure elevation. These findings better define human blood volume responses during altitude acclimatization.

Acclimatization↗
PubMed1986

Electronic measurement of erythrocyte volume and volume heterogeneity in horses during erythrocyte regeneration associated with experimental anemias.

Anemia was induced in three groups of horses by moderate or severe acute hemorrhage, or by acetyl phenylhydrazine-induced hemolysis (Groups I, II, and III, respectively). Serial hemograms were done on a multichannel automated blood cell counter with histogram capability. Changes in hematocrit, mean cell volume, erythrocyte number, red cell distribution width (RDW), and standard deviation of erythrocyte volume were examined over time. Significant increases in mean cell volume were first detectable by days 17, 20, and 14 and reached maximum by days 43, 41, and 29, in Groups I, II, and III, respectively (P less than 0.05). Increased mean cell volume was interpreted as reflecting accelerated erythrocyte regeneration; however, not all horses with accelerated regeneration had changes in mean cell volume. Estimated erythrocyte production rate correlated poorly with hematocrit nadir and change in mean cell volume (r = 0.37 and r = 0.36, respectively, P greater than 0.05). In some horses effective regeneration occurs without development of macrocytosis. Mean cell volume remained increased after other parameters returned to control values, suggesting that mean cell volume values may provide retrospective evidence of altered erythrocyte turnover. Anisocytosis as indicated by significant increases in the standard deviation was greatest during the early part of the regenerative response, reaching maximum values on days 30, 28, and 21 in Groups I, II, and III, respectively, and began to decrease as homogeneous repopulation with macrocytes occurred. Red cell distribution width increased significantly only in severe hemorrhage and hemolysis groups, reaching mean maximum values of 24.3 on day 20 and of 26.4 on day 21 in Groups II and III, respectively (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia↗
PubMed1988

Dialysis-induced change in erythrocyte volume: effect on change in blood volume calculated from packed cell volume.

Blood volume (BV) change during hemodialysis is often monitored by packed cell volume (PCV). This assumes erythrocyte volume is constant. We tested this by dialyzing 5 patients for 2 hours against high (154 mmol/l), normal (140 mmol/l) and low (126 mmol/l) dialysate sodium concentrations. Erythrocyte water content, calculated from measured blood and plasma water contents, decreased with high and increased with low dialysate sodium concentrations. Erythrocyte volume, calculated from mean corpuscular hemoglobin concentration (MCHC) decreased 3.8% with high concentration dialysate and increased 2.5% when dialysate concentration was low. These changes correlated significantly (r = 0.80, p less than 0.01) with alterations in plasma sodium. Mean corpuscular volume (MCV), measured with a Coulter-S Plus Counter did not alter because of a methodological artefact. BV change can be calculated from PCV when plasma concentrations of osmotically active substances are changed only if allowance is made for altered erythrocyte volume.

Adult↗
PubMed1990

Erythrocyte volume and blood pressure in a cross-sectional population-based study.

A reduction in mean erythrocyte volume has been reported in some strains of genetically hypertensive rat, and more recently it has been suggested that a similar alteration might be found in human essential hypertension. The relationship between erythrocyte volume and blood pressure was therefore studied in a random sample of an untreated male working population (n = 317; age 45.1 +/- 6.4 years, mean +/- s.d.). Neither systolic nor diastolic blood pressures were found to be related to erythrocyte volume (r = 0.022 and r = -0.014, respectively); in fact, erythrocyte volume was not different across quintiles of blood pressure. Smokers (n = 171) had lower blood pressure and a greater erythrocyte volume than non-smokers or ex-smokers (n = 144; 91.6 +/- 4.7 versus 88.2 +/- 5.5 fl; P less than 0.001), and heavy drinkers (greater than 110 g ethanol/day) had higher blood pressure and a greater erythrocyte volume compared with the rest of the study population (P less than 0.01). However, after adjustment of erythrocyte volume for these two potentially confounding factors, again no statistical association was found with blood pressure. The present study, therefore, does not support the hypothesis of a negative association between erythrocyte volume and blood pressure, whereas it confirms that the smoking habit and habitual alcohol intake are strong determinants of erythrocyte volume.

Adult↗
PubMed1997

Measurement of erythrocyte volumes in splenectomized horses and sham-operated horses at rest and during maximal exercise.

Erythrocyte volumes of thoroughbred horses were measured. The volumes of splenectomized horses and sham-operated horses 2 hr after injection of 50Cr-tagged erythrocytes (at rest) and during maximal exercise were measured using the non-radioactive isotope 50Cr. Because splenic erythrocytes are released into circulation during exercise, it was estimated that the erythrocyte volumes of the sham-operated horses during maximal exercise are larger than those of the horses at rest. However, the erythrocyte volumes of the sham-operated horses at rest were about equal to those during maximal exercise. In the splenectomized horses, furthermore, erythrocyte volumes at rest and those at exercise were nearly equal. From these results, blood stored in the equine spleen is gradually mixed with circulating blood, and it was clarified that the phenomenon was completed within 2 hr. Although it is basically impossible to measure the circulating erythrocyte volume at rest using the erythrocyte tagged method, we observed that it is possible to measure the total erythrocyte volume using the 50Cr method. Also, the plasma volumes of the splenectomized horses during maximal exercise were found to be slightly smaller than those at rest. On the other hand, in the sham-operated horses, the plasma was decreased by a large quantity after maximal exercise. Therefore, it was suggested that the spleen participates in the phenomenon involving the disappearance of plasma from circulation due to exercise.

Animals↗
PubMed1989

[Erythrocyte volume distribution curves: a parameter for evaluating erythrocyte preparations].

The volume distribution of erythrocytes in ACD-AG blood and in human erythrocyte concentrations was investigated by means of computer-assisted techniques of hematological analysis. The storage-dependent distribution was described by the content of discrete class areas. Erythrocytes with a volume below 72 fl are only slightly capable of changing their volume. Their condition predisposes them to selection in the receiver's organism. Their percentage amount correlates with the share of cells ineffective of transfusion. The concentration of cells with a volume above 72 fl is discussed with ACD-AG blood (78% on the 42nd day), with CDS-AG erythrocyte concentrate (66% on the 20th day) and with SAG-M erythrocyte concentrate (74% on the 35th day) together with findings about the transfusional survival rate.

Blood Preservation↗