The rate constants for a boronate ion were determined for the first time using the reaction systems of 3-nitrophenylboronic acid (3-NO2PhB(OH)2) with ethylene glycol (EG) and propylene glycol (PG) in an alkaline solution: the rate constants (25 degrees C, I = 0.10 M) for the reactions of 3-NO2PhB(OH)3- are 1.2 M(-1) s(-1) (EG) and 1.5 M(-1) s(-1) (PG), which are at least 10(3) times smaller than those for the reactions of 3-NO 2PhB(OH)2 [1.0 x 10(4) M(-1) s(-1) (EG) and 5.8 x 10(3) M(-1) s(-1) (PG)].

Reaction systems of boronic acid (RB(OH2), R = phenyl or 3-fluorophenyl) with diols and no proton ambiguity were elaborately set up, and kinetic measurements were conducted to elucidate the relative reactivities of RB(OH)2 and RB(OH)3(-). In the reactions of phenylboronic and 3-fluorophenylboronic acids with propylene glycol, the reactivity order was: RB(OH)2 >> RB(OH)3(-), whereas in the reactions of 3-pyridylboronic acid with Tiron and 2,2'-biphenol, the reactivity of RB(OH)2 was comparable to that of RB(OH)3(-). These results are in contrast to those that have been previously reported, and widely accepted for over thirty years, that concluded that the reactivity of RB(OH)3(-) is several orders of magnitude higher than that of RB(OH)2. The reactivity of Tiron with 3-pyridylboronic acid is affected by the protonation of one of its sulfonate groups.

The cyclic micro-deformation of the arterial wall with pulsatile flow was measured to get fundamental data for estimation of the mechanical stress in endothelial cells. The descending aorta (1-2 mm diameter) of an anesthetized rat was exposed under thoracotomy. The displacement measuring system was assembled with the charge coupled devise (CCD) of laser sensor. The movement of laser beam (670 nm wave length) reflected at the vessel wall was calibrated to the movement of the arterial wall. The fluctuating movement was also measured at four points marked on the vessel wall with CCD camera to distinguish the circumferential movement from the longitudinal one. The results showed that the present designed system has enough resolution to measure the arterial vessel wall cyclic-micro-fluctuation, which is 10 percent of diameter in the circumferential direction without deformation in the longitudinal direction with the cardiac beating in vivo.