The observed equilibrium constants (Kobs) of the P-choline hydrolysis reaction have been determined under physiological conditions of temperature (38 degrees) and ionic strength (0.25 M) and physiological ranges of pH and free [Mg2+]. Using sigma and square brackets to indicate total concentrations: (see article.) The value of Kobs has been found to be relatively insensitive to variations in pH...

BACKGROUND AND PURPOSE The role of hydrogen peroxide in the regulation of cerebral arterial tone is not completely understood. Previous studies have demonstrated that hydrogen peroxide causes vasodilation of small cerebral arteries. The present study was designed to determine the mechanisms responsible for relaxations of large cerebral arteries to hydrogen peroxide. METHODS Rings of canine mi...

BACKGROUND AND PURPOSE--Cerebral arteriolar dilation to N-methyl-D-aspartate (NMDA) is a neuronally mediated process that is sensitive to cerebral ischemia. We tested the hypothesis that pretreatment with transcription or translation inhibitors preserves the vascular response to NMDA after global cerebral ischemia. METHODS--Pial arteriolar diameters were measured in anesthetized piglets by use ...

The asymmetric unit of the title compound, C(12)H(8)N(2)·C(10)H(10)N(2)·2H(2)O, contains one half-mol-ecule of phenazine, one half-mol-ecule of naphthalene-1,5-diamine and one water mol-ecule. The phenazine and naphthalene-1,5-diamine mol-ecules are located on inversion centers. The water mol-ecules serve as bridges between the naphthalene-1,5-diamine mol-ecules and also between the naphthalene...

OBJECTIVE To determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects. METHODS Phenylephrine or potassium chloride concentration-dependent relaxation response of aortic smooth muscles to matrine was studied in the precontracted guinea pigs. RESULTS Matri...

Biliary, ureteric and intestinal colic are extremely common clinical conditions associated with smooth muscle spasm. In the present study, antispasmodic activity was carried out against acetylcholine (10-640 ng/ml)-induced contractions on guinea pig ileum. Acetylcholine (10-640 ng/ml) induced concentration-dependent contraction of smooth muscle. Diclofenac, in varying concentration (9.4 x 10(-5...

A poly-amidosulfonic acid and multi-wall carbon nanotubes composite (PASA/MWNTs) modified electrode has been constructed by electropolymerization on glassy carbon electrode (GCE). The electrochemical behaviors of hydroquinone (HQ) and catechol (CC) were investigated using cyclic and differential pulse voltammetries (DPVs) at the prepared electrode. Separation of the reductive peak potentials fo...

The fabrication and application of a novel electrochemical detector (ED) with nano crystalline Mn-doped lead dioxide film chemically modified electrode (CME) for liquid chromatography (LC) were described. The Mn-doped PbO2 film was characterized by scanning tunnel microscope. The electrochemical behaviors of tetrahydrobiopterin, monoamine neurotransmitters and their metabolites at the CME were ...

BACKGROUND Arginine vasopressin (AVP) is widely used in the treatment of critical diseases with hypotension, but the reports about its effect on gastrointestinal motility are controversial. The purpose of this study was to characterize the role of AVP in the regulation of colonic motility and the underlying mechanism. METHODS The contraction of the circular muscle strips (CM) of colon in male...

Propofol is widely used for neurosurgical anesthesia; however, its effects on the pial microvasculature are unknown. We therefore evaluated the direct effects of propofol on pial microvessels in rabbits. Pial microcirculation was visualized using a closed cranial window technique in 20 Japanese white rabbits. In the first experiment (n=14), after baseline hemodynamic measurements, the cranial w...