Although there is evidence that the Rho/Rho kinase pathway and protein kinase C (PKC) are involved in the development of cerebral vasospasm, the mechanism by which subarachnoid hemorrhage (SAH) activates these pathways is unclear. A large body of evidence points to oxyhemoglobin (OxyHb) as a major causative component of blood clot responsible for vasospasm. Therefore, the present studies were c...

Cell swelling triggers in most cell types an outwardly rectifying anion current, I(Cl,swell), via volume-regulated anion channels (VRACs). We have previously demonstrated in calf pulmonary artery endothelial (CPAE) cells that inhibition of the Rho/Rho kinase/myosin light chain phosphorylation pathway reduces the swelling-dependent activation of I(Cl,swell). However, these experiments did not al...

To study rhodopsin biosynthesis and transport in vivo, we engineered a fusion protein (rho-GFP) of bovine rhodopsin (rho) and green fluorescent protein (GFP). rho-GFP expressed in COS-1 cells bound 11-cis retinal, generating a pigment with spectral properties of rhodopsin (A(max) at 500 nm) and GFP (A(max) at 488 nm). rho-GFP activated transducin at 50% of the wild-type activity, whereas phosph...

The effect of interaural correlation (rho) on the loudness for noisebands was measured using a loudness-matching task in naive listeners. The task involved a sequence of loudness comparisons for which the intensity of one stimulus in a given comparison was varied using a one-up-one-down adaptive rule. The task provided an estimate of the level difference (in decibels) for which two stimulus con...

In this paper we consider a fractional optimization problem that minimizes the ratio of two quadratic functions subject to a strictly convex quadratic constraint. First using the extension of Charnes-Cooper transformation, an equivalent homogenized quadratic reformulation of the problem is given. Then we show that under certain assumptions, it can be solved to global optimality using semidefini...

Rho-associated kinase (Rho-kinase/ROCK/ROK) is an effector of the small GTPase Rho and belongs to the AGC family of kinases. Rho-kinase has pleiotropic functions including the regulation of cellular contraction, motility, morphology, polarity, cell division, and gene expression. Pharmacological analyses have revealed that Rho-kinase is involved in a wide range of diseases such as vasospasm, pul...

The small guanosine triphosphatase Rho and its target, Rho kinase, play important roles in both blood pressure regulation and vascular smooth muscle contraction. Rho is activated by agonists of receptors coupled to cell membrane G protein, such as angiotensin II and phenylephrine. Once Rho is activated, it translocates to the cell membrane where it, in turn, activates Rho kinase. Activated Rho ...