Alice Y.M. Wong

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A model is proposed to elucidate the cause and mechanism of mechanical alternans in cardiac muscle in terms of discrete calcium movements. Mechanical alternans, the cause of which lies within the borders of excitation-contraction-coupling (ECC), is analyzed. In this case, the "input" of the ECC system (the action potentials and intervals) is constant while(More)
More than 900 cases of scarlet fever were recorded in Hong Kong during January-July, 2011. Six cases were complicated by toxic shock syndrome, of which 2 were fatal. Pulsed-field gel electrophoresis patterns suggested a multiclonal epidemic; emm12 was the predominant circulating type. We recommend genetic testing of and antimicrobial resistance monitoring(More)
A model of smooth muscle cell is proposed to describe the mechanisms by which intracellular calcium (Cai) is regulated when the cell is stimulated by noradrenaline (NA)/agonist (Ag) or depolarized. The intracellular Ca2+ store is comprised of two calcium pools: A-store which is sensitive to inositol 1,4,5 trisphosphate (IP3) and C-store, insensitive to IP3(More)
A model is proposed to describe the interval-strength relationship in mammalian cardiac muscle in terms of "discrete" calcium movements associated with each cycle. The sarcoplasmic reticulum is assumed to be comprised of three functional sub-compartments: (1) The "main calcium store" which contains most of the calcium (predominantly bound) and is(More)
A model is proposed to describe the Na-Ca exchange in excitable tissues. The present scheme requires a carrier mechanism that exchanges 3Na for 1Ca across the membrane under the electrochemical gradient of Na. The carriers, assumed to be trivalent anions, have monovalent and divalent sites; Ca and Na can compete only at the second site. The partially and(More)
OBJECTIVE (1) To measure regional phasic myocardial red cell flux during a cardiac cycle using a laser Doppler velocimeter. (2) To test the responses of regional red cell flux to a vasodilator (adenosine), a vasoconstrictor (angiotensin II), and an inotrope (isoproterenol). METHODS Using an anaesthetised open-chest rabbit with the pericardium intact a(More)
BACKGROUND The benefit of administering supplementary oxygen during elective Caesarean section under regional anaesthesia is controversial. It has been hypothesized that its use would improve fetal oxygenation in the event of a prolonged uterine incision-to-delivery (U-D) interval. Our aim was to test this hypothesis in a prospective, randomized,(More)
To study systolic pressure gradients developed between the left ventricular wall, its chamber, and the aortic root, in one group of dogs left ventricle ventral wall intramyocardial pressure, left ventricular outflow tract pressure, and aorta pressure were compared with aortic flow as well as left ventricular dimension changes during control conditions as(More)