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We speculated that the sphingosine-1-phosphate (S1P) receptor S1P(2), which uniquely inhibits cell migration, might mediate inhibitory effects on endothelial cell migration and angiogenesis, different from S1P(1) and S1P(3). Mouse vascular endothelial cells, which endogenously express S1P(2) and S1P(3), but not S1P(1), responded to S1P and epidermal growth factor (EGF) with stimulation of Rac, migration, and the formation of tube-like structures on the Matrigel. The S1P(3)-antagonist VPC-23019 abolished S1P-induced, G(i)-dependent Rac stimulation, cell migration, and tube formation, whereas the S1P(2)-antagonist JTE-013 enhanced these S1P-induced responses, suggesting that S1P(2) exerts inhibitory effects on endothelial Rac, migration, and angiogenesis. S1P(2) overexpression markedly augmented S1P-induced, G(i)-independent inhibition of EGF-induced migration and tube formation. Finally, the blockade of S1P(2) by JTE-013 potentiated S1P-induced stimulation of angiogenesis in vivo in the Matrigel implant assay. These observations indicate that in contrast to S1P(1) and S1P(3), S1P(2) negatively regulates endothelial morphogenesis and angiogenesis most likely through down-regulating Rac.

In order to determine the effect of pimobendan on sympathetic nerve activity and cardiopulmonary baroreflex (CPB), electrocardiogram, direct arterial pressure, central venous pressure (CVP) and cardiac output were recorded along with muscle sympathetic nerve activity (MSNA) in 8 healthy young men. CPB function was evaluated before and 60 min after oral administration of 5 mg pimobendan using the response of MSNA to lower body negative pressure (LBNP) of − 5 and − 10 mm Hg. The same protocol also was performed during handgrip exercise. Cardiac index, MSNA increased and CVP decreased significantly (p

The hypothesis that a coronary vasomotion disorder may exist in the entire coronary artery tree in patients with vasospastic angina was investigated by examining the coronary responses to atrial pacing (130 beats/min) before and after the administration of ergonovine (16 micrograms) into nonspastic coronary arteries. Seven patients with angiographically normal coronary arteries and focal spasm in the right coronary artery and 7 control patients with atypical chest pain and angiographically normal coronary arteries without spasm were studied. Great cardiac vein flow (GCVF) and left anterior descending coronary artery diameters (CDs) were measured by the thermodilution method and quantitative arteriography, respectively. Although the CDs before ergonovine were similar in the 2 groups, the pacing-induced increased in GCVF before ergonovine administration was smaller in patients with vasospastic angina than in control patients (22 +/- 4% vs 49 +/- 11%, respectively; p0.05). After ergonovine administration, pacing both increased GCVF and decreased anterior regional coronary resistance (ACR) to a lesser extent in patients with vasospastic angina than in control patients (GCVF, 16 +/- 4% vs 47 +/- 8%, respectively [p0.01]; ACR, -12 +/- 3% vs -29 +/- 3%, respectively [p0.01]). The decreases in CDs in patients with vasospastic angina observed after ergonovine administration were greater than those in control patients (-18 +/- 2% vs -9 +/- 2%, respectively; p0.05). Thus, not only epicardial, but also resistance coronary arteries are affected by the coronary vasomotion disorder in the nonspastic vascular bed in patients with vasospastic angina.

The arterial pressure (AP) response to hemodialysis was studied with echocardiography and strain gauge plethysmography in 17 patients with end-stage renal disease; mean AP was unchanged in seven (group A) and was reduced by more than 10 mm Hg in 10 patients (group B). Following dialysis, body weight decreased and heart rate increased equally in both groups. Ejection fraction did not change in the two groups. Left ventricular end-diastolic volume fell by 13 +/- 10% in group A and by 24 +/- 16% in group B. Cardiac index (CI) fell in group B, but remained unchanged in group A. Systemic vascular resistance (SVR) did not change in both groups. The change in mean AP before and after dialysis was significantly correlated with that in Cl (r = 0.49, p less than 0.05), but not with that in SVR. Calf venous pressure-volume curves were not different between the two groups before dialysis. Hemodialysis shifted the curve toward the volume axis for group B but not for group A. These results suggest that hypotension following dialysis is mainly due to the fall in cardiac output, in which increases in venous distensibility play an important role.

This paper describes a newly developed parameter identification method of induction machine. Identification procedure consists of two steps: one is at initial state of standstill and the other is at operating state. In each step, on-line identification of parameters indispensable to description of machine dynamics can be realized by observing behaviors of stator current and voltage. They are stator winding self-inductance, transient inductance, rotor circuit time constant and stator winding resistance. At standstill state, they are identified from stator voltage wave to ramp current. At operating state these parameters are also identified by solving a set of equations obtained from vectorial relation between stator current and voltage. This identification technique is applied to PWM drive system and can lead to parameter self-tuning in ac servo control system.

This paper describes a newly developed parameter identification method for three-phase induction machines. The identification is performed in two steps corresponding to the two states of the machine, namely the initial standstill state and the normal operating state. In each step, on-line identification of parameters indispensable to description of the machine dynamics can be realized by observing the behaviour of the stator current and voltage. These parameters are stator winding self-inductance, transient inductance, rotor circuit time constant and stator winding resistance. At standstill state, they are identified from the stator voltage waveform, when a ramp current is supplied to the stator by a dc power amplifier. At the operating state these parameters are identified by solving a set of equations obtained from the phasor relationship between stator current and voltage. This identification technique is applied to a PWM drive system and can lead to parameter self-tuning in an ac servo control system.