Effects of sodium and potassium concentrations and pH on equine erythrocyte volume and deformability

During strenuous exercise, equine erythrocyte deformability is transiently decreased. Decreased deformability is associated with increased cell volume, decreased cell density and increased intracellular sodium, potassium and chloride concentrations. To better understand these changes, we attempted to reproduce exercise-associated changes in erythrocytes in vitro by adjusting plasma sodium, potassium and pH to levels which occur during racing activity. Increasing plasma sodium to 145 meq/1 and plasma potassium to 8 meq/1 resulted in decreased erythrocyte filterability, increased cell volume, and increased intracellular sodium, potassium and chloride. Incubation of erythrocytes with frusemide and bumetanide, but not ouabain or [(dihydroindenyl)oxy]alkanoic acid (DIOA), attenuated these changes. Decreasing plasma pH to 7.0 also decreased erythrocyte filterability, increased cell volume, and increased intracellular concentrations of sodium, potassium and chloride. Ouabain, but not frusemide or bumetanide, prevented the decrease infilterability and attenuated the increase in intracellular sodium. Addition of DIOA exacerbated the effect of pH on erythrocyte filterability. Therefore, exercise-associated changes in erythrocyte deformability, size and electrolyte concentration can be reproduced in vitro by increasing plasma sodium and potassium concentrations and by decreasing pH.     

Haemorrheology of equine platelet-neutrophil aggregates

The filterability of platelet-neutrophil aggregates through filters containing 5 μm pores was determined to evaluate the potential of plateletneutrophil aggregates to alter blood flow in the microvasculature. Incubation of platelet-neutrophil mixture with platelet-activating factor (PAF) and with 0.5 μM adenosine diphosphate (ADP) resulted in large platelet-neutrophil aggregates which rapidly plugged filter pores. Incubation of platelet-neutrophil mixtures with lower concentrations of ADP resulted in small platelet-neutrophil aggregates that contained only one neutrophil. Filtration of these samples resulted in a 1.3-, 3.2- and 3.7-fold increase in initial filtration pressure at ADP concentrations of 0.05, 0.15 and 0.25 μM, respectively. We conclude that platelet-neutrophil aggregates have reduced deformability and may alter blood flow in the microvasculature.     

术中持续腹腔热灌注对人体血流动力学和血液流变学的影响

本文观察了胃肠道肿瘤切除后应用腹腔热灌注（Ｃｏｎｔｉｎｕｏｕｓｈｙｐｅｒｔｈｅｒｍｉｃｐｅｒｉｔｏｎｅａｌｐｅｒｆｕｓｉｏｎ，ＣＨＰＰ）对人体血流动力学和血液流变学的影响。结果表明：ＣＨＰＰ在升高体温的同时，增强心功能、改善血液流变性，提高了组织器官的微循环灌注，而对血压、心率的影响较小。     

Filterability of density-separated equine erythrocytes, neutrophils and mononuclear cells

The filterability of density-separated fractions of red blood cells (RBC), neutrophils and mononuclear cells was evaluated to determine their relative contribution to resistance to blood flow. Increasing RBC density was associated with smaller cell size, greater haemoglobin concentration, and improved filterability. Filtration of RBC, after adrenaline-induced splenic contraction, failed to identify a population of non-deformable RBC. Leucocytes filtered less readily compared to RBC. Neutrophils and mononuclear cells produced similar initial pressure increments but mononuclear cells had a greater potential to plug pores in the filters. Our results indicate both RBC and leucocytes may contribute to resistance to blood flow. A subpopulation of non-deformable RBC could not be identified in circulating blood or in blood after adrenaline-induced splenic contraction.     

Haemorrheology of equine platelet-neutrophil aggregates

The filterability of platelet-neutrophil aggregates through filters containing 5 μm pores was determined to evaluate the potential of plateletneutrophil aggregates to alter blood flow in the microvasculature. Incubation of platelet-neutrophil mixture with platelet-activating factor (PAF) and with 0.5 μM adenosine diphosphate (ADP) resulted in large platelet-neutrophil aggregates which rapidly plugged filter pores. Incubation of platelet-neutrophil mixtures with lower concentrations of ADP resulted in small platelet-neutrophil aggregates that contained only one neutrophil. Filtration of these samples resulted in a 1.3-, 3.2- and 3.7-fold increase in initial filtration pressure at ADP concentrations of 0.05, 0.15 and 0.25 μM, respectively. We conclude that platelet-neutrophil aggregates have reduced deformability and may alter blood flow in the microvasculature.