Publications by authors named "JI Kambayashi"

Objective: OPC-28326 is a selective alpha-adrenergic antagonist with preferential binding to the alpha(2C)-adrenergic receptor (alpha(2C)-AR) subtype. This study observed the effect of OPC-28326 on skin temperature and digital blood flow following an acute cold challenge in patients with Raynaud's phenomenon secondary to scleroderma.

Methods: The study was designed as a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of OPC-28326 (oral doses of 10 mg or 40 mg) or placebo.

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We investigated the basis for the difference in the cardiotonic effects of the PDE3 inhibitors cilostazol and milrinone in the rabbit heart. Cilostazol displayed greater selectivity than milrinone for inhibition of cAMP-PDE activity in microsomal vs cytosolic fractions from rabbit heart. This difference was due to the inhibition of significantly less cytosolic cAMP-PDE activity by cilostazol compared to milrinone.

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Glycoprotein (GP) VI, a collagen receptor, plays an important role in collagen-mediated platelet aggregation and adhesion. To date, GPVI expression has been found only in platelets and megakaryocytes. In the present studies, we have demonstrated that GPVI was also expressed in cultured human umbilical vein endothelial cells (HUVEC) at both transcript and protein levels.

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Cilostazol, a potent phosphodiesterase 3 inhibitor and anti-thrombotic agent, was recently shown to inhibit adenosine uptake into cardiac myocytes and vascular cells. In the present studies, cilostazol inhibited [ H]-adenosine uptake in both platelets and erythrocytes with a median inhibitory concentration (IC ) of 7 micro M. Next collagen-induced platelet aggregation was studied and it was found that adenosine (1 micro M ), having no effect by itself, shifted the IC of cilostazol from 2.

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OPC-28326 has been reported to selectively increase femoral blood flow in open-chest dogs and autoperfused canine femoral artery preparations. Preliminary data indicated that OPC-28326 has a high affinity at the alpha2-adrenoceptor. In the present study, we tested OPC-28326 in isoflurane anesthetized rats at a dose of 3 mg/kg of body weight, given intraduodenally.

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1. In human platelets, arachidonic acid is mainly metabolized by the two enzyme systems; cyclo-oxygenase and 12-lipoxygenase. Cyclo-oxygenase produces prostaglandin H(2) which is further converted to thromboxane B(2).

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Glycoprotein (GP) Ib (alpha and beta) in platelets forms a noncovalent hetero-oligomeric complex with GPIX and GPV and serves as a receptor for von Willebrand factor (vWF), which mediates the initial adhesion of platelets to the subendothelium after vascular damage and also plays a role in thrombin-induced platelet activation. We investigated the interaction between GPIbalpha and FcgammaIIA receptor using a yeast two-hybrid system and mutagenesis, and we identified residues R542G543R544 in GPIbalpha and D298D299D300 in FcgammaIIA receptor as the primary interaction sites. These results further confirmed the interaction between GPIbalpha and FcgammaIIA receptor and support the hypothesis that the signal transduction of GPIb-IX-V that leads to platelet activation may be partially mediated through FcgammaIIA receptor.

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Cancer invasion and metastasis require action of tumor-associated proteases, which degrade the extracellular matrix. It has been reported that calpain, a calcium-activated neutral protease and a thiol protease regulated by Ca²+;, proteolyzes estrogen recepor (ER) and that calpain may play an important role in the regulation of ER function. In the present study, the activities of calpain were measured in human normal breast tissues and breast cancer tissues stratified by estrogen receptor levels.

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Phyllodes tumor is an uncommon breast neoplasm characterized by a proliferation of both stromal and epithelial elements. In 1989, two young patients with phyllodes tumors were referred to our surgical department because of the detection of breast lumps. Interestingly, both patients also had epilepsy and had been taking anticonvulsants.

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Protein phosphatase (PP) activities have long been known in platelets, but their physiological roles in platelet reactions are not well understood. Since the discovery of the okadaic acid (OA) class of compounds, potent and cell-permeable PP 1/2A inhibitors, evidence for the active involvement of PP1/2A in platelet reactions has rapidly accumulated. This article reviews the possible involvement of PP1/2A in platelet function by focusing on the effects of OA class compounds on agonist-induced platelet reactions.

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In patients over 70 years of age with disabling leg ischaemia, femorofemoral crossover bypass with an externally supported polytetrafluoroethylene (PTFE) graft is the treatment of choice for unilateral occlusion of the iliac artery. Over a 6-year period, 18 elderly patients underwent femorofemoral bypass, six of whom had received percutaneous transluminal angioplasty before surgery for stenosis of the contralateral external iliac artery (donor artery). Symptoms of ischaemia recurred in three patients because of deterioration of the donor iliac artery more than 2 years after surgery, although all three grafts were well visualized by angiography.

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