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Biomedical subjects

K Q Wang

Publications and source records attributed to K Q Wang.

16 recordsLinked to original sources
PubMed1990

Prosthetic heart valves: waveform comparisons and average value disposition for pulsatile flow in vitro.

With the development of the in vitro testing of heart valves, the standardization of the test methods becomes increasingly important and they should also be improved continuously. This paper discusses the problems of waveform comparison and average value dispositions. In the pulsatile model driven by pneumatics, the pressures before and after the valve, and the flow through it, are measured as three one-dimensional variates. The mean values are calculated according to the FDA and the ISO. A comparison and analysis of experimental waveforms indicate that, for basically the same ranges of pressures and flow rate, the flow curves of different types of valve are clearly different. The mean values and the waveforms in the time domain should be taken into consideration synthetically so that the pusatile characteristics of the valve can be more completely reflected. Using numerical filtering methods to treat the waveforms allows for better comparisons between the measured results taken from the different devices. By means of the constellation graphical method for treating mean values as multivariates, it is feasible to classify the valves and to judge their qualities under conditions of pulsatile flow.

Computer Graphics↗
PubMed1990

The differences of serum cholesterol and lipoproteins in animals susceptible and nonsusceptible to atherosclerosis.

The differences of serum lipid and lipoprotein (LP, profiles of animals susceptible (rabbit) and nonsusceptible (Beijing duck) to atherosclerosis as well as the distribution of apolipoprotein (apo) A-I and its catabolism in vivo were studied. Eight items, i.e. total cholesterol (TC), high density lipoprotein (HDL) cholesterol, triglyceride, percentage of alpha-LP and beta-LP, beta-LP concentration, lecithin cholesterol acyl transferase (LCAT), and agarose and polyacrylamide gel electrophoresis of both species were assayed before and after feeding a high fat, high cholesterol diet. Results indicate that the exogenous cholesterol consumed by Beijing ducks was carried and transported by HDL, while that in rabbits was transported by low density lipoprotein (LDL). The biological half lives of apo A-I in serum and in HDL were 41.1 +/- 2.4 and 42.8 +/- 1.7 h respectively, and its distribution in different organs was in the order of liver greater than kidney greater than spleen greater than lung greater than heart greater than intestine greater than muscles greater than aorta. These results show that the liver is the major organ for metabolizing HDL apo A-I, and the kidney is also important. The results also imply that in Beijing ducks the cholesterol carried by HDL may be catabolized through apo A-I receptors in the liver and kidney. The differences in cholesterol binding and in lipoprotein and apolipoprotein metabolism of the two species provide important clues for the elucidation of the pathogenesis of atherosclerosis.

Animals↗
PubMed1990

Treatment of experimental Coxsackie B-3 viral myocarditis with Astragalus membranaceus in mice.

A murine model system for observing the effect of Astragalus Membranaceus (AM) on experimental myocarditis caused by Coxsackie B-3 virus (CB3V) was developed in 4-week-old male BALB/C mice. Gross, histopathologic and ultrastructural examinations of the infected-AM treated group showed that the severity and involved area of the myocardial lesions became milder and smaller than those in the infected-NS treated mice. The total lesion area, and the total lesion area/total myocardial area examined (%) and virus titer in the former group were also smaller and lower than those in the latter group. The results suggest that AM is effective in the inhibition of Coxsackie B virus propagation and protection of myocardium in mouse myocarditis.

Animals↗
PubMed1985

Isolation and adaptation characteristics of hepatitis A virus in primary African green monkey kidney cells: production of antigen useful for ELISA serology.

Four strains of hepatitis A virus (HAV) were isolated from four fecal samples of patients with type A hepatitis by using primary African green monkey kidney (PAGMK) cells or FRhK-4 cells. In all four samples viral antigen became detectable in PAGMK cells at the 3rd passage level after 9 weeks of incubation; detectable levels of antigen were reached earlier in FRhK-4 cells. An enzyme-linked immunosorbent assay (ELISA) was used to detect HAV antigen (HAV-Ag). Blocking experiments with negative and positive human sera and with paired marmoset sera established the identity of the virus. Infectious virus appeared to be both intracellular and extracellular. Although HAV-Ag could not be detected in culture medium by ELISA, the HAV infectivity titers of culture media were as high as those of cell-associated viruses (greater than 10(6) TCID50/0.2 ml). The passage procedure was simplified by using only virus isolated from cell-free medium as seed material, and the HAV strains were successfully propagated for 12 consecutive passages through PAGMK cells at 2-week intervals. The tissue-culture-produced HAV-Ag proved to be useful as a source of antigen in ELISA for detection of human anti-HAVIgG and IgM. The HAV strains adapted to PAGMK cells lost or decreased their ability to grow in FRhK-4 cells, while one strain adapted to FRhK-4 cells grew equally well in both cell systems.

Acclimatization↗