Effect of erythrocyte aggregation at normal human levels on functional capillary density in rat spinotrapezius muscle

2006 ◽  
Vol 290 (3) ◽  
pp. H941-H947 ◽  
Author(s):  
Sangho Kim ◽  
Aleksander S. Popel ◽  
Marcos Intaglietta ◽  
Paul C. Johnson
Keyword(s):  
Arterial Pressure ◽  
Blood Cell ◽  
Red Blood Cell ◽  
High Speed ◽  
Capillary Density ◽  
Functional Capillary Density ◽  
Erythrocyte Aggregation ◽  
Reduced Pressure ◽  
Healthy Humans ◽  
Plasma Skimming

Previous studies have shown that functional capillary density (FCD) is substantially reduced by erythrocyte aggregation. However, only supranormal levels of aggregability were studied. To investigate the effect of erythrocyte aggregability at the level seen in healthy humans, the FCD of selected capillary fields in rat spinotrapezius muscle was determined with high-speed video microscopy under normal (nonaggregating) conditions and after induction of erythrocyte aggregation with Dextran 500 (200 mg/kg). To examine shear rate dependence, the effect was studied both at normal and reduced arterial pressures (50 and 25 mmHg), the latter achieved by short periods of hemorrhage. In a separate study, volume flow was determined in arterioles (52.1 ± 3.7 μm) under the same conditions. Before Dextran 500 infusion, FCD fell to 91% and 76% of control values, respectively, when arterial pressure was reduced to 50 and 25 mmHg. After Dextran 500 infusion, FCD was 96% at normal arterial pressure and fell to 79% and 37% of normal control values at 50 and 25 mmHg. All FCD values were significantly lower after dextran infusion. FCD reduction after lowering arterial pressure or dextran infusion appeared to be due to plasma skimming rather than capillary plugging. Reduction of FCD by dextran at reduced pressure was compensated by increased red blood cell flux in capillaries with red blood cell flow. We conclude that the level of aggregability seen in healthy humans is an important determinant of FCD only at reduced arterial pressure.

Effect of Intensified Red Blood Cell Aggregability on Arterial Pressure and Mesenteric Microcirculation

1993 ◽  
Vol 45 (3) ◽  
pp. 233-242 ◽  
Author(s):  
George Mchedlishvili ◽  
Leila Gobejishvili ◽  
Nino Beritashvili
Keyword(s):  
Arterial Pressure ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Mesenteric Microcirculation

Study on the Turbulent Injury Principle of Blood in the High-Speed Spiral Blood Pump

2011 ◽  
Vol 393-395 ◽  
pp. 992-995
Author(s):  
Zhong Yun ◽  
Chuang Xiang ◽  
Xiao Yan Tang ◽  
Fen Shi
Keyword(s):  
Shear Stress ◽  
Flow Field ◽  
Blood Cell ◽  
Turbulent Flow ◽  
Red Blood Cell ◽  
Blood Cells ◽  
High Speed ◽  
Internal Flow ◽  
Blood Pump ◽  
Turbulent Flow Field

The strongly swirling turbulent flow in the internal flow field of a high-speed spiral blood pump(HSBP), is one of important factors leading to the fragmentation of the red blood cell(RBC) and the hemolysis. The study on the turbulent injure principle of blood in the HSBP is carried out by using the theory of waterpower rotated flow field and the hemorheology. The numerical equation of the strongly swirling turbulent flow field is proposed. The largest stable diameter of red blood cells in the turbulent flow field is analyzed. The determinant gist on the red blood cell turbulent fragmentation is obtained. The results indicate that in the HSMP, when turbulent flow is more powerful, shear stress is weaker, the vortex mass with energy in flow field may cause serious turbulent fragmentation because of the diameter which is smaller than the RBC’s. The RBC’s turbulent breakage will occur when the Weber value is larger than 12.

Effects of red blood cell aggregation on myocardial hematocrit gradient using two approaches to increase aggregation

2006 ◽  
Vol 290 (2) ◽  
pp. H765-H771 ◽  
Author(s):  
Ozlem Yalcin ◽  
Funda Aydin ◽  
Pinar Ulker ◽  
Mehmet Uyuklu ◽  
Firat Gungor ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Control Level ◽  
Three Dimensional ◽  
Cell Aggregation ◽  
Plasma Viscosity ◽  
Covalent Attachment ◽  
Erythrocyte Aggregation ◽  
Rbc Aggregation ◽  
A New Technique

The normal transmyocardial tissue hematocrit distribution (i.e., subepicardial greater than subendocardial) is known to be affected by red blood cell (RBC) aggregation. Prior studies employing the use of infused large macromolecules to increase erythrocyte aggregation are complicated by both increased plasma viscosity and dilution of plasma. Using a new technique to specifically alter the aggregation behavior by covalent attachment of Pluronic F-98 to the surface of the RBC, we have determined the effects of only enhanced aggregation (i.e., Pluronic F-98-coated RBCs) versus enhanced aggregation with increased plasma viscosity (i.e., an addition of 500 kDa dextran) on myocardial tissue hematocrit in rapidly frozen guinea pig hearts. Although both approaches equally increased aggregation, tissue hematocrit profiles differed markedly: 1) when Pluronic F-98-coated cells were used, the normal transmyocardial gradient was abolished, and 2) when dextran was added, the hematocrit remained at subepicardial levels for about one-half the thickness of the myocardium and then rapidly decreased to the control level in the subendocardial layer. Our results indicate that myocardial hematocrit profiles are sensitive to both RBC aggregation and to changes of plasma viscosity associated with increased RBC aggregation. Furthermore, they suggest the need for additional studies to explore the mechanisms affecting RBC distribution in three-dimensional vascular beds.

scholarly journals High Speed Digital Video Capillaroscopy: Nailfold Capillary Shape Analysis and Red Blood Cell Velocity Measurement

2007 ◽  
Vol 2 (2) ◽  
pp. 81-92 ◽  
Author(s):  
Masao WATANABE ◽  
Mizuho MATSUBARA ◽  
Toshiyuki SANADA ◽  
Hiroaki KURODA ◽  
Masaki IRIBE ◽  
...  
Keyword(s):  
Blood Cell ◽  
Shape Analysis ◽  
Red Blood Cell ◽  
Velocity Measurement ◽  
High Speed ◽  
Digital Video ◽  
Cell Velocity ◽  
Red Blood Cell Velocity

scholarly journals P2X7 Expression is Greater in Red Blood Cell Membranes of Humans with Type 2 Diabetes than Healthy Humans.

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Kelly Marie Thuet ◽  
David A Ford ◽  
Elizabeth A Bowles ◽  
Mary L Ellsworth ◽  
Randy S Sprague ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Membranes ◽  
Healthy Humans ◽  
Red Blood Cell Membranes

Hemorrhagic hypotension induces arteriolar vasomotion and intermittent capillary perfusion in rat pancreas

1994 ◽  
Vol 267 (5) ◽  
pp. H1936-H1940 ◽  
Author(s):  
B. Vollmar ◽  
G. Preissler ◽  
M. D. Menger
Keyword(s):  
Blood Cell ◽  
Microscopic Analysis ◽  
Capillary Density ◽  
Functional Capillary Density ◽  
Intravital Fluorescence Microscopy ◽  
Capillary Perfusion ◽  
Induced Hypotension ◽  
Rat Pancreas ◽  
Hemorrhagic Hypotension ◽  
Acinar Tissue

Hemorrhage-induced intermittent capillary perfusion and its relation to arteriolar vasomotion was studied in rat pancreatic acinar tissue using intravital fluorescence microscopy. During prehemorrhage conditions, microscopic analysis of the pancreatic microcirculation displayed neither arteriolar vasomotion nor intermittency of capillary perfusion (n = 22 animals). Hemorrhage-induced hypotension of 40 mmHg provoked arteriolar vasomotion in 18 of 22 animals and 59 of 115 arterioles studied. The maximum relative amplitude of arteriolar vasomotion was 44 +/- 8% (range 12–81%), and vasomotion frequency averaged 4.73 +/- 0.11 cycles/min. Hemorrhagic hypotension was further accompanied by 1) a decrease of functional capillary density [length of red blood cell-perfused capillaries per area of tissue under investigation (cm/cm2)] from 515 +/- 3 cm-1 at baseline to 386 +/- 3 cm-1 (P < 0.05) and 2) the instantaneous occurrence of intermittency of capillary perfusion in all observation areas (N = 220) of the 22 animals studied. The frequency of intermittency of capillary perfusion (4.72 +/- 0.14 cycles/min) did not differ from the frequency of arteriolar vasomotion, which implies a causal relationship between these two hemorrhage-induced microvascular mechanisms with the probable aim to counteract the decrease of functional capillary density.

Microvascular responses to hemodilution with Hb vesicles as red blood cell substitutes: influence of O2 affinity

1999 ◽  
Vol 276 (2) ◽  
pp. H553-H562 ◽  
Author(s):  
Hiromi Sakai ◽  
Amy G. Tsai ◽  
Ronald J. Rohlfs ◽  
Hiroyuki Hara ◽  
Shinji Takeoka ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Carrying Capacity ◽  
Capillary Density ◽  
Microvascular Perfusion ◽  
Phospholipid Vesicles ◽  
Molar Ratios ◽  
Allosteric Effector ◽  
Syrian Golden Hamsters ◽  
Optimal Value

Phospholipid vesicles encapsulating purified hemoglobin (HbV) were developed to provide O2-carrying capacity to plasma expanders. Microvascular perfusion was determined for HbV with different O2 affinity (P50 = 9, 16, and 30 mmHg) prepared by coencapsulating pyridoxal 5′-phosphate (PLP) at the molar ratios of [PLP]/[Hb] = 0, 0.5, and 3, respectively (cf. hamster blood, P50: 28 mmHg), and suspended in 8 g/dl human serum albumin (HSA). Eighty percent of the red blood cell (RBC) mass of conscious Syrian golden hamsters fitted with dorsal skinfold windows was substituted with either of the HbV-HSA suspensions, washed hamster RBC suspended in HSA (RBC-HSA), and HSA alone. All three HbV-HSA groups and RBC-HSA groups showed stable blood pressure and heart rate, which could not be sustained with HSA alone. Only the HbV (P50 = 9)-HSA group showed an increase in arterial O2tension (89.8 ± 14.7 mmHg, baseline 58.4 ± 4.0 mmHg) because of hyperventilation, and microvascular perfusion was decreased, indicating that facilitated O2 unloading of HbV by decreasing the O2 affinity (increasing P50) with PLP as an allosteric effector is important. Microvascular perfusion and microvascular and interstitial O2tensions in the HbV (P50 = 16 and 30)-HSA groups were significantly higher than those in the HSA group. The O2 release rate from the HbV was 18–32 s−1 vs. 4.4 s−1 for RBC. Functional capillary density was improved from 17 to 41% on average by decreasing P50 from 30 to 16 mmHg, which appears to be an optimal value for the P50 in this system.

Predictors of Red Cell Transfusion in Medically III Patients.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4180-4180
Author(s):  
Maggie M. Yuen ◽  
David R. Anderson ◽  
Caren Rose
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Blood Cell ◽  
Serum Creatinine ◽  
Red Blood Cell ◽  
Red Blood Cell Transfusion ◽  
Red Cell ◽  
Medically Ill ◽  
Red Cell Transfusion ◽  
Medically Ill Patients

Abstract Although red cell transfusion is a relatively common treatment in medically ill patients, much is not known about the clinical determinants used to guide its use. We conducted a retrospective, case-controlled chart review of admissions to the medical teaching units (MTU) at this center (Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia). Forty-two patients who received red blood cell transfusion during admission to the MTU from January to March 31, 2004. Clinical data collected included: age, gender, indication for MTU admission, co-morbid disease, smoking, admission hemoglobin, pre- and post-transfusion hemoglobin, arterial pressure of oxygen, lactic acidosis, parameters of shock, presence of active bleeding, and need for surgery. Logistic regression analysis was used to identify significant clinical determinants of transfusion. Red blood cell transfusion rate was 8%. Of admission diagnoses and co-morbidities, only cancer was associated with a trend for transfusion (p=0.07). Those who received red blood cell transfusion had significantly lower admission hemoglobin levels (p=0.005), higher serum creatinine (p=0.02), and lower mean arterial pressure (p=0.01). Significant predictive clinical factors of red blood cell transfusion included congestive heart failure (OR=3.72, CI 1.034, 27.160), admission hemoglobin level (d/L, OR=0.956, CI 0.927, 0.986), mean arterial pressure (mm Hg, OR=0.942, p=0.005) and serum creatinine (ml/min, OR=1.008, CI 1.003, 1.014). In conclusion, predictors of red blood cell transfusion for medically ill patients include low admission hemoglobin, renal insufficiency, and low blood pressure.

Sign in / Sign up

Export Citation Format

Share Document