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Biomedical subjects

X Y Xu

Publications and source records attributed to X Y Xu.

7 recordsLinked to original sources
PubMed1992

Human influenza A (H1N2) viruses isolated from China.

Reassortant influenza A viruses bearing H1 haemagglutinin and N2 neuraminidase were isolated from humans in China between December 1988 and March 1989. As primary isolation of influenza A (H1N2) viruses from humans had not been reported previously, it was of interest to determine the genetic origin of these virus isolates. The haemagglutinins of the H1N2 viruses were antigenically and genetically related to those of H1 viruses isolated world-wide since 1986, and the neuraminidases of these viruses were antigenically and genetically related to those of recent H3N2 viruses. Partial sequencing of each gene segment of three of the H1N2 viruses revealed that all gene segments except that encoding the haemagglutinin gene were derived from virus of the H3N2 subtype. Sequence differences amongst the neuraminidase, nucleoprotein and nonstructural genes of these three H1N2 reassortant viruses as well as the isolation of reassortants in seven laboratories over a 4 month period make it unlikely that the H1N2 viruses are laboratory artefacts. The spread of these reassortant viruses to other countries has not yet been documented.

Adolescent↗
PubMed1992

Flow studies in canine artery bifurcations using a numerical simulation method.

Three-dimensional flows through canine femoral bifurcation models were predicted under physiological flow conditions by solving numerically the time-dependent three-dimensional Navier-stokes equations. In the calculations, two models were assumed for the blood, those of (a) a Newtonian fluid, and (b) a non-Newtonian fluid obeying the power law. The blood vessel wall was assumed to be rigid this being the only approximation to the prediction model. The numerical procedure utilized a finite volume approach on a finite element mesh to discretize the equations, and the code used (ASTEC) incorporated the SIMPLE velocity-pressure algorithm in performing the calculations. The predicted velocity profiles were in good qualitative agreement with the in vivo measurements recently obtained by Jones et al. The non-Newtonian effects on the bifurcation flow field were also investigated, and no great differences in velocity profiles were observed. This indicated that the non-Newtonian characteristics of the blood might not be an important factor in determining the general flow patterns for these bifurcations, but could have local significance. Current work involves modeling wall distensibility in an empirically valid manner. Predictions accommodating these will permit a true quantitative comparison with experiment.

Animals↗
PubMed1992

[Alveolar echinococcosis in China: current data].

Very few information about alveolar echinococcosis in China is available outside the country. The aim of the authors is to give some precisions about the human cases and the infection in the natural animal hosts. It occurs in 3 distinct foci which comprise poor and remote rural areas. Approximately, 420 cases of human disease have been detected, and the most intense focus is Ningxia province in central China. In all areas, the adult tapeworm is frequently found in V. vulpes, V. corsac, and in the domestic dog. The intermediate hosts differ from an area to the others. Their infection rate is high in the central and the northern foci. More researches are needed for improving our knowledge about the epidemiology of the disease. But the actual major requirement is to apply control measures as health education and medical information.

Animals↗
PubMed1991

[The influence of sodium ferulate on hypotensive effect and urinary excretion of TXB2 after captopril in essential hypertensive patients].

In the present study, the influence of sodium ferulate (SF) on hypotensive effect and urinary excretion of TXB2 after captopril (CAP) was observed in 44 patients with essential hypertension. A single oral dose of CAP (50 mg) decreased mean arterial pressure (MAP) from 16.25 +/- 0.85 to 13.65 +/- 1.14 kPa, n = 28, (P less than 0.01), and increased urinary TXB2 excretion significantly from 119.12 +/- 57.12 to 183.32 +/- 78.61 pg/min, n = 16, (P less than 0.05). The administration of SF 300 mg/d for one day did not affect the MAP. CAP in combination with SF induced a decrease both in MAP from 16.33 +/- 1.14 to 13.83 +/- 1.77 kPa, n = 16, (P less than 0.01) and urinary TXB2 excretion from 155.89 +/- 69.64 to 133.43 +/- 60.01 pg/min, n = 16, (P greater than 0.05) though the latter was not so significant. Compared with the administration of CAP alone, the combination of CAP and SF induced stronger hypotensive effect (P less than 0.05) and the increased urinary TXB2 excretion could be inhibited by SF, but the inhibition to angiotensin converting enzyme was the same. These results suggested that the increased urinary TXB2 excretion by CAP can be inhibited and the hypotensive effect of CAP is potentiated by SF in essential hypertensive patients.

Antihypertensive Agents↗
PubMed1990

A review of the numerical analysis of blood flow in arterial bifurcations.

Arterial bifurcation flow has been of special interest for some years because of its important role in the formation of atherosclerotic plaques and thrombi. To investigate the flow phenomena analytically, four major factors need to be accommodated--the three-dimensionality of a general bifurcation, the pulsatile nature of the laminar flow, the distensibility of the arterial wall and the non-Newtonian character of the blood. In this review, both engineering and medical aspects of each factor are carefully surveyed. It is demonstrated that the latest generation of computational fluid dynamics codes can treat this problem area and that it is both feasible and desirable to investigate the effects of each independent factor.

Arteries↗
PubMed1990

Grey dynamic model of predicting the long-term effects of drugs and its application to pirenzepine.

In an attempt to approach the quantification of the dynamics of drug effects and the prediction of the long-term effects of drugs, a grey dynamic model was proposed and it was applied to predict the long-term effects of pirenzepine on pupils and peripheral leukocytes in dogs. The inconsiderable relative errors between the predicted and observed values suggest that the model-based equations for pupil diameter, neutrophils (%) and lymphocytes (%) which, obtained by fitting the data measured before and during initial 16 wk experiment, are acceptable for predicting the effects after 20- and 24-wk treatment with the drug.

Animals↗