Disease relevance of Hct

• In these CRF mice, the hematocrit (Hct) dropped from a prenephrectomy baseline of approximately 55% to 40% after induction of renal failure [1].
• Thus, patients with chronic renal failure have a sustained regulatory feedback mechanism between Hct and SEp, which probably works at a lower level [2].
• The known negative correlation between SEp and hematocrit (Hct) was not apparent, probably because of the loss of renal mass accompanying progress of anemia and renal insufficiency [2].
• Induction of hemolytic anemia with phenylhydrazine resulted in a drop in the Hct from approximately 50% to 30%, and an approximate 8- to 10-fold increase in the reticulocyte count [3].
• These findings suggest that increasing Hct increases blood viscosity, shear stress, and NO production, leading to vasodilation and mild hypotension [4].

High impact information on Hct

• Repeat implantations in these same mice were associated with an acquired refractoriness in the Hct response consistent with alloimmunization to donor Epo+ MSCs [5].
• Mutants expressed normal hematocrit values (Hct = 45.9 +/- 4.0) until 12 months but became anemic from 15 months on (Hct = 30.9 +/- 3.9; P <.05) [6].
• Adult GATA-1(low) mice are profoundly thrombocytopenic (platelet counts [x 10(9)/L] 82.0 +/- 28.0 vs 840 +/- 170.0 of their control littermates, P <.001) but have a normal hematocrit (Hct) (approximately.47 proportion of 1.0 [47%]) [7].
• The mice were killed on day 3 and the hematocrit (Hct), reticulocyte count, and numbers of erythroid and myeloid hematopoietic progenitor cells (colony-forming unit-erythroid [CFU-E], burst-forming unit [BFU]-E, and CFU-granulocyte-macrophage [GM]) were quantitated in the femoral marrow and spleen using hematopoietic colony-forming assays [3].
• The use of either r-HuEPO or HU induced a significant increase in hemoglobin (Hb), hematocrit (Hct), erythrocyte K+ and a decrease in percent reticulocytes, suggesting improved erythrocyte survival [8].

Biological context of Hct

• We determined if the implantation of murine MSCs engineered to release erythropoietin (Epo) would be feasible in major histocompatibility complex (MHC)-mismatched allogeneic mice without immunosuppression, and we monitored hematocrit (Hct) as a reporter of MSC graft survival [5].
• Moreover, a stringent control of mEpo gene expression and Hct levels in the absence of any background activity was maintained over a 10-month period by injecting as little as 1 microg of a single plasmid containing the rtTA2(S)-S2 expression cassette and the Tet-responsive mEpo cDNA [9].
• Larger increases of Hct (>19% of baseline) led blood viscosity to increase >50%, overwhelming the NO effect through a significant viscosity-dependent increase in vascular resistance, causing MAP to rise above baseline values [4].
• Increasing Hct 7-13% of baseline decreased mean arterial blood pressure (MAP) by 13 mmHg [4].
• Hematologic parameters such as Hb, hematocrit (Hct), mean cell volume (MCV), membrane-associated denatured Hb, and the oxygen equilibration curve were improved in chimeric hemoglobinopathy mice [10].

Anatomical context of Hct

• Moreover, surgical removal of the viscous collagen organoid 24 days after implantation led to reduction of Hct to baseline levels within 14 days [11].
• In addition, the Hct correlated with the sum of the CLup by bone marrow and spleen in both types of mice, and the correlation lines were superimposable [12].
• In this study we tested the capability of these trans-activators to control expression of mouse erythropoietin (mEpo) and to modulate hematocrit (Hct) increase in vivo on delivery of plasmids into quadriceps muscles of adult mice by DNA electroinjection [9].
• Hematocrit (Hct) of awake hamsters and CD-1 mice was acutely increased by isovolemic exchange transfusion of packed red blood cells (RBCs) to assess the relation between Hct and blood pressure [4].
• However, the improvement in Hb, Hct, and MCV was not sustained despite stable levels of donor leukocyte engraftment [10].

Associations of Hct with chemical compounds

• Nitrate/nitrite plasma levels of Hct-augmented hamsters increased relative to control and L-NAME treated animals [4].

Other interactions of Hct

• After a single i.v. injection with high doses (5 x 10(9) and 10(10) pfu), a dramatic increase in hematocrit (Hct) and long-term Epo expression (6 months at this time) were observed [13].
• However, addition of CLT to r-HuEPO, to HU, or to combined r-HuEPO plus HU led to statistically significant increase in Hb, Hct, and erythrocyte K+ compared with any of the regimens without CLT [8].
• In SAD 1 mice, hematocrit (Hct) and hemoglobin (Hb) decreased significantly with low Mg diet and increased significantly with high-Mg diet [14].
• Hamsters pretreated with the nitric oxide (NO) synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) and endothelial NOS-deficient mice showed no change in MAP when Hct was increased by <19% [4].

Analytical, diagnostic and therapeutic context of Hct

• Kidney damage was evaluated using [51Cr]EDTA residual activity, blood urea nitrogen (BUN) and percentage haematocrit (%Hct) as end-points [15].

References