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Biomedical subjects

T C Hung

Publications and source records attributed to T C Hung.

27 records · Page 2Linked to original sources
PubMed1977

Mechanical trauma in leukocytes.

Mechanical and surface traumas in cardiopulmonary bypass circuits alter the function and morphology of human leukocytes. The effect of controlled in vitro shear stess (0 to 2,000 dynes/cm2, 2 to 10 min, 37 degrees C) on electronic cell count, morphology, adhesiveness, and phosphatase cytochemical staining was studied on whole blood from normal donors. Electronic cell counts droppped significantly after shear stress exposure (25% at 600 dynes/cm2 for 10 min). The frequency of disrupted leukocytes in blood smears increased with shear stress above 150 dynes/cm2, and aggregates of the disrupted cells appeared after exposure to higher shear stresses (450 dynes/cm2, 10 min). Cytochemical staining of the alkaline phosphatase in the granules of intact neutrophils was significantly reduced by the application of shear stress (150 dynes/cm2 for 10 min, or greater), but staining of acid phosphatase-containing granules was almost unaffected. Increased cell retention in columns of nylon fibers suggests that increased leukocyte adhesiveness results from exposure to shear stress. Thus exposure to shear stress may alter or disrupt leukocyte morphology and function at values somewhat lower than the 1,500 dynes/cm2 for 2 min which is required to hemolyze erythrocytes.

Cell Adhesion↗
PubMedDate not supplied

Characteristics of blood rheology in patients during Novacor left ventricular assist system support.

Blood rheologic properties were studied in 11 patients on Novacor LVAS support (1-126 days) as a bridge to transplantation. Overall, these patients showed slight increases in mean blood viscosity and red cell rigidity. Their mean plasma fibrinogen was in the upper normal range. However, the degree of rheologic change observed, and the individual factors affected most, were unique to each patient and hemorheologic results correlated well with the patient's clinical status.

Adult↗
PubMedDate not supplied

Erythrocyte deformability in patients on left ventricular assist systems.

Preliminary hemorheologic studies using clinical filtration techniques on blood cell suspensions have suggested that changes in erythrocyte (RBC) deformability occur during left ventricular assist system (LVAS) support. In the biophysics literature, it is generally accepted that the elastic properties of the RBC membrane complex affect the microcirculatory deformability of the whole cell (cytoplasmic pathologies excepted). This paper compares single cell measurements of the surface shear elastic modulus, mu, of the RBC membrane complex (determined using micropipette aspiration) to available clinical filtration pressure data during Novacor LVAS support, over 33 and 126 days in four patients.

Adult↗
PubMedDate not supplied

Effects of long-term Novacor artificial heart support on blood rheology.

This study presents characteristics of hemorheology for six patients during long-term support (85-144 days) on a Novacor left ventricular assist device (LVAD) as a bridge-to-cardiac transplantation. Results indicate that a certain "baseline" rheology can be identified in patients whose support was uneventful. However, in the patients who had one or more neurologic episodes during support, these events were associated with altered hemorheology, including increases in plasma and relative blood viscosity, and red cell rigidity.

Blood Proteins↗
PubMedDate not supplied

Artificial heart. Hemorrheology and transient ischemic attacks.

Hemorrheology was studied in patients undergoing artificial heart support as a bridge-to-cardiac transplantation. Abnormal hemorrheology was seen in two patients, one on a Jarvik-7 total artificial heart, and the other on a Novacor left ventricular assist device. Both of these patients suffered neurologic episodes. The rheology of these two patients coincided well with their clinical status, and was accompanied by marked increases in relative blood viscosity, erythrocyte rigidity, fibrinogen concentration, and platelet aggregation. Results show that improving hemorrheology may be a beneficial avenue to pursue in preventing or treating transient ischemic attacks or other complications in patients during support with mechanical devices.

Blood Flow Velocity↗