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H Ariyoshi

Publications and source records attributed to H Ariyoshi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Shear-stress causes polarized change in cytoplasmic calcium concentration in human umbilical vein endothelial cells (HUVECs).

Using a newly developed, parallel-plate flow-chamber for confocal laser scanning microscopy (CLSM), we studied the distribution and temporal changes in intracellular Ca2+ concentration ([Ca2+]i) in individual HUVECs stimulated by shear-stress. In the presence of ATP, shear-stress (1-10 dyne/cm2) caused a rise in [Ca2+]i, whereas no such response was observed in the absence of ATP or in the presence of Ni2+, a nonspecific, plasma membrane Ca2+ channel blocker. These results suggest that both ATP and Ca2+ influx are essential for the increase in [Ca2+]i in response to shear stress at less than 10 dyne/cm2. Analysis of [Ca2+]i distribution revealed a repetitive intracellular 'Ca2+ wave' originating from the upstream edge of the cell in some populations of HUVECS, which was transmitted to the downstream of the cell. The polarized [Ca2+]i response induced by shear-stress might be integral to polarized cellular reactions such as remodeling of endothelial lining.

Adenosine Triphosphate↗
PubMed1997

Renal pelvic cancer with tumor thrombus in the vena cava inferior. A case report and review of the literature.

Renal pelvic cancer with a large vein tumor thrombus is very rare. We report a case of transitional cell carcinoma of the right renal pelvis with tumor thrombus in the inferior vena cava. Based on the radiological findings, the patient was diagnosed having renal cell carcinoma with tumor thrombus in the vena cava preoperatively. Radical nephrectomy with thrombectomy was performed. A literature review of 17 reported cases revealed that 13 cases (76.5%) were diagnosed as renal cancer preoperatively. Prognosis of transitional cell carcinoma with vena cava tumor thrombus is relatively poor compared to that of renal cell carcinoma with a large vein tumor thrombus.

Carcinoma, Renal Cell↗
PubMed1997

[TUT-7 early phase II clinical study for various solid tumors and hematologic malignancies].

An early Phase II study with TUT-7 (menogaril), a new anthracycline antitumor antibiotic, was conducted in patients with various malignant tumors at 81 departments of 65 institutions nationwide. One course of TUT-7 treatment consisted of seven (7) or fourteen (14) consecutive days of administration at 75 or 100 mg/body/day with two-week drug withdrawal; at least two courses of treatment were given in principle. Among the 165 patients registered, 145 patients were eligible and 128 patients were evaluable for antitumor efficacy. In 11 patients with malignant lymphoma, one (1) had CR and five (5) had PR (54.5%); in three (3) patients with prostate cancer, one (1) had PR (33.3%); and in 12 patients with uterine cervical cancer, two (2) had PR (16.7%). Adverse drug reactions frequently observed were digestive organ disorders (anorexia and nausea/vomiting) and malaise. The abnormality in laboratory tests observed frequently was myelosuppression (leukopenia and neutropenia).

Adult↗
PubMed1996

Platelet microparticles: a carrier of platelet-activating factor?

Platelet-activating factor (PAF) has been considered to be released in a soluble form from activated platelets. Also a considerable number of microparticles were released from stimulated platelets. To evaluate the possibility that microparticles contain PAF, the amount of PAF in whole activated platelets, microparticles and the suspending medium was determined by means of bioassay. The total amount of PAF released from 3 x 10(8) platelets activated with thrombin (0.5 U/ml) plus collagen (10 micrograms/ml) for 10 minutes was 4.6 +/- 1.5 x 10(-12) mol (n = 8, mean +/- S.D.). Eighty-seven percent of the PAF released from platelets was associated with microparticles. PAF released in microparticles is susceptible to plasma acetylhydrolase and may be localized on the outer surface of microparticles. This is the first report implicating the role of microparticles as a novel carrier of mediators formed in the cells.

Acetylesterase↗
PubMed1996

Prevalence of impaired responsiveness to epinephrine in platelets among Japanese.

The responsiveness of platelets only to epinephrine was markedly impaired in 23/140 (16%) healthy Japanese. The impaired responsiveness was not altered by changes in time and environment. Circulating level of catecholamines did not affect the responsiveness of platelets to epinephrine. A pilot family study indicated a possible familial nature of the defect. 3H methyl-yohimbine binding studies indicated that this defect was due to the decreased number of alpha 2 adrenergic receptor. Despite the defect, the potentiating effect of epinephrine on platelet aggregation stimulated by a low dose of ADP was normal. This abnormality is not apparently associated with any bleeding disorders and the clinical implication is unknown at present. It is, however, essential to acknowledge the prevalence of such defect in pursuing research on platelets stimulated by epinephrine.

Adenosine Diphosphate↗
PubMed1996

Simultaneous digital imaging analysis of cytosolic calcium and morphological change in platelets activated by surface contact.

The dynamic change of cytoplasmic Ca(2)+ concentration ([Ca(2)+]i) and morphological change were investigated simultaneously by confocal laser scanning microscopy using fluo-3 and by differential interference contrast optics in platelets activated by contact with the following types of surfaces: native glass and glass treated with poly-L-lysine (PLL), fibrinogen (Fg), or von Willebrand factor (vWF). The initial [Ca(2)+]i values just after the surface contact were comparable (approximately 100 nM) among platelets deposited on the four surface types. On the PLL-surface, no morphological change or [Ca(2)+]i elevation was observed. Glass-, Fg-, and vWF-surface adhered platelets showed pseudopod formation and spreading associated with the inhomogeneous [Ca(2)+]i rise. The platelets on the Fg-surface were the most active in terms of [Ca(2)+]i rise and morphological change. During pseudopod formation, the mean [Ca(2)+]i value was maximal and localized high [Ca(2)+]i zones were observed inside pseudopods, as well as in the center of the platelets. After spreading, high [Ca(2)+]i zones still remained in the center of the cell. This new technique enabled simultaneous observation of [Ca(2)+]i and cell shape and we clearly demonstrated a close relationship between [Ca(2)+]i and morphological alterations.

Analog-Digital Conversion↗
PubMed1996

Separate analysis of nuclear and cytosolic Ca2+ concentrations in human umbilical vein endothelial cells.

Ca2+ concentration inside human umbilical vein endothelial cells was studied separately in cytosol and nucleus by a confocal laser scanning microscopy using fluo-3. The in vivo calibration curve for cytosol and nucleus showed good linearity between fluorescence intensity and Ca2+ concentration in cytosol ([Ca2+]i) and nuclei ([Ca2+]n). After calibration, [Ca2+]n was constantly higher than [Ca2+]i before and after the chelation of extracellular Ca2+ suggesting an active Ca2+ accumulation system on nuclear membrane. [Ca2+]n was also constantly higher than [Ca2+]i after the stimulation of thrombin (0.05 U/ml), FCS (10%), and thapsigargin (Tsg, 1 microM). The temporal change of [Ca2+]n and [Ca2+]i was identical, and [Ca2+]i gradient towards the nucleus and peripheral or central [Ca2+]n rise was observed after these stimulations. From these results, [Ca2+]n is not only regulated by the active Ca2+ accumulation system on nuclear membrane at rest but also the generation of inositol-triphosphate. FCS caused heterogeneous [Ca2+]n or [Ca2+]i rise from cell to cell; single spike or oscillatory change of [Ca2+]n and [Ca2+]i was observed in about 56% of cells, which were completely abolished by the chelation of extracellular Ca2+, suggesting that FCS stimulated [Ca2+]n and [Ca2+]i rise solely depending on Ca2+ influx from extracellular medium. The higher concentration of [Ca2+]n and heterogeneous [Ca2+]n rise may have important roles in nuclear-specific cellular responses.

Aniline Compounds↗
PubMed1996

The possible risk of lower-limb sclerotherapy causing an extended hypercoagulable state.

The risk of thrombosis after lower-extremity sclerotherapy is still an unresolved issue. This study was conducted to investigate the influence of sclerotherapy on coagulation and fibrinolysis by examining 20 patients who underwent surgical procedures, 10 of whom were treated by surgery alone (control group), while the other 10 were given sclerotherapy using 1% hydroxypolyaetoxydodecan as polidocanol (sclerotherapy group). Sex, age, and severity of disease was comparable between the two groups. No significant difference was found in the transient elevation of acute phase proteins, C-reactive protein (CRP), or fibrinogen. Thrombin antithrombin III complex (TAT), a marker of coagulation, transiently increased following treatment. In the control group, TAT peaked 3 days after treatment, whereas in the sclerotherapy group the elevation was prolonged, peaking 7 days after treatment. Elevation of the markers of fibrinolysis, plasmin plasmin inhibitor complex (PIC) and fibrin degradation products (FDP), was slower than that of TAT, peaking 7 days after treatment in both groups, the plasma PIC being significantly enhanced 7 days after treatment in the sclerotherapy group. A significant decrease in the platelet count was observed 3 days after treatment in the sclerotherapy group. These results suggest that sclerotherapy may enhance coagulation or fibrinolysis after surgical procedures.

Adult↗
PubMed1996

Association of localized Ca2+ gradients with redistribution of glycoprotein IIb-IIIa and F-actin in activated human blood platelets.

We monitored the intracellular distribution of ionized free Ca2+ concentration ([Ca2+]i) in individual human platelets by digital imaging fluorescence microscopy with fura 2 during platelet activation induced by surface contact or a soluble platelet agonist (thrombin). Contact of platelets with glass resulted in pseudopod formation and spreading, accompanied by a nonuniform rise in [Ca2+]i. The rise in [Ca2+]i was maximal during pseudopod formation. Locally elevated [Ca2+]i was frequently found in pseudopodia and at the edge and core of spread platelets. This pattern was faithfully duplicated by the local pattern of distribution of the cytoskeletal components F-actin, gelsolin, and surface glycoproteins (GP) IIb-IIIa but not by calmodulin. Platelets stimulated by thrombin also showed an inhomogeneous rise in [Ca2+]i, which was well correlated with the staining of F-actin and GPIIb-IIIa. Cytochalasin D, an inhibitor of actin polymerization, inhibited the inhomogeneous increase or redistribution of F-actin and GPIIb-IIIa but did not inhibit the rise in mean [Ca2+]i. These observations suggest that a localized change in [Ca2+]i may be associated with cytoskeletal reorganization and redistribution of GPIIb-IIIa in activated platelets.

Actins↗
PubMed1995

Spatial distribution and temporal change in cytosolic pH and [Ca2+] in resting and activated single human platelets.

In human platelets, a rapid rise in cytoplasmic Ca2+ and slower rise in cytoplasmic pH follow stimulation by thrombin. With the Ca2+ probe Fura-2 and the pH probe SNARF-1 for digitized fluorescence microscopy, we studied simultaneously the distribution and changes with time of [pH]i and [Ca2+]i in individual human platelets. In platelets coloaded with both probes, the probes had no detectable fluorescence at each other's excitation wavelength. The monovalent cation ionophore, nigericin (2 microM), produced a homogeneous rise in pH but no change in [Ca2+]. Platelets, in contact with glass, spread and developed an irregular, apparently mutually independent rise in both [Ca2+] and pH. Stimulation of platelets by thrombin 1.0 U/ml elevated [Ca2+]i and produced slow alkalinization without initial acidification. Replacement of extracellular Na+ by choline abolished thrombin-induced alkalinization, but had no effect on thrombin-induced [Ca2+]i elevation. ADP 10 microM caused a rapid rise of [Ca2+]i and transient alkalinization. Most stimulated platelets developed a gradient in pH, that was highest in the center. ADP and thrombin caused oscillation of [Ca2+]i but not of [pH]i. We conclude that alkalinization in stimulated platelets, presumably involving Na+/H+ antiport, is not essential for the rise of [Ca2+]i that may accompany it.

Adenosine Diphosphate↗
PubMed1995

c-myb affects intracellular calcium handling in vascular smooth muscle cells.

The protooncogene c-myb is responsible for elevating intracellular calcium concentration ([Ca2+]i) at the G1/S interface in vascular smooth muscle cells (VSMC). However, the molecular components of this pathway are undefined, and the biological effects of increased levels of divalent cation are unknown. We have demonstrated that growth-arrested c-myb-transfected VSMC, compared with wild type VSMC, exhibit a fourfold increased number of insulin-like growth factor I (IGF-I) receptors, increased amount of secreted IGF-I activity, and a twofold increased level of [Ca2+]. The c-myb transfected cells, compared with wild type cells, also possess a twofold increased rate of calcium influx and a twofold decreased rate of calcium efflux. The elevated calcium influx rate of transfected cells is decreased to that of wild type cells with IGF-I neutralizing antibody, whereas the decreased calcium efflux rate of transfected cells is increased to that of wild type cells with antisense c-myb oligonucleotides. Proliferating wild type VSMC exhibit an increased calcium influx rate in late G1, which is dependent on production of augmented amounts of IGF-I activity but not increased levels of IGF-I receptors. The wild type VSMC also show a decreased calcium efflux rate at the same point in the cell cycle, which is dependent on expression of c-myb. The treatment of wild type cells with antisense c-myb or IGF-I receptor oligonucleotides induces a late G1 block in cell proliferation, which can be overcome by exposure to the calcium ionophore, 4-bromo-A-27318, in amounts sufficient to raise [Ca2+]i to levels observed at the G1/S interface. We conclude that IGF-I/IGF-I receptors and c-myb are involved in control of [Ca2+]i at the G1/S interface by separately regulating the rates of calcium influx and efflux and that elevated levels of divalent cation are necessary for progression of VSMC into the S phase of the cell cycle.

Animals↗
PubMed1995

TMB-8 and dibucaine induce tyrosine phosphorylation and dephosphorylation of a common set of proteins in platelets.

Dibucaine and 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), which are local anesthetics, affect diverse functions of many cell types. For example, platelet aggregation is inhibited by both, and both cause changes in platelet morphology and structure. Little is known of the mechanisms. We found that both dibucaine (0.125-0.5 mM) and TMB-8 (0.25-1.0 mM) induced rapid tyrosine phosphorylation of several platelet proteins (160, 70-75, and 40 kDa) and dephosphorylation of a 62- to 64-kDa protein detectable by a specific antiphosphotyrosine monoclonal antibody (4G10). Platelet aggregation induced by alpha-thrombin (10 nM) was inhibited by the local anesthetics in approximately the same dose range. Neither dibucaine nor TMB-8 induced activation of protein kinase C (PKC) or myosin light-chain kinase. Their activation was not essential for tyrosine phosphorylation induced by local anesthetics. However, an increase in tyrosine phosphorylation of several proteins (95-130 kDa) induced by alpha-thrombin (10 nM) was inhibited by dibucaine (0.5 mM) or TMB-8 (0.5 mM). Furthermore, when dibucaine (0.5 mM) was added 1 min after addition of alpha-thrombin (10 nM), disaggregation was paralleled to dephosphorylation of many proteins, including those mentioned. Tyrosine phosphorylation and dephosphorylation of specific proteins may account for some of the diverse effects of local anesthetics on platelets and other cells. Addition of TMB-8 (0.5 mM) or dibucaine (0.5 mM) also inhibited activation of PKC, induced by alpha-thrombin (10nM), suggesting that some of the inhibitory effects of dibucaine or TMB-8 may be due to inhibitory effects of local anesthetics on PKC.

Blood Platelets↗
PubMed1995

Participation of calpain in protein-tyrosine phosphorylation and dephosphorylation in human blood platelets.

The possible role of calpains in protein-tyrosine phosphorylation in platelets was examined by the use of the cell-permeant calpain inhibitor calpeptin. In platelets stimulated by 1 U/mL thrombin, protein-tyrosine phosphorylation was maximal after 2 minutes and was followed by protein-tyrosine dephosphorylation. Calpeptin (30 mumol/L) or vanadate (2 mmol/L) enhanced protein-tyrosine phosphorylation and delayed protein-tyrosine dephosphorylation. The effects of these two compounds were not additive. We also observed proteolysis of pp60src and autoproteolysis of mu-calpain. Cleavage of the former was significantly slower than that of the latter and slower than protein-tyrosine dephosphorylation. The activity of protein-tyrosine phosphatase in the platelet lysate was transiently increased to 190% by addition of Ca2+. Ca(2+)-dependent activation of protein-tyrosine phosphatase was not observed in the presence of leupeptin. Those observations suggest that platelet calpains may be involved in modulation of protein-tyrosine phosphorylation through activation of protein-tyrosine phosphatase rather than through the inactivation of pp60src, a mechanism that was previously suggested.

Blood Platelets↗
PubMed1994

[A comparative clinical study on flucytosine alone and in combination with fluconazole in hematological malignancies: a multicenter study using the envelope method].

Two different flucytosine (5-FC) treatment regimens, one by itself and the other in combination with fluconazole (FLCZ) were compared in chemotherapy against mycotic infections in 60 patients with hematological diseases. The patients in a randomized fashion were assigned to the two treatments. In the combination regimen, the two drugs were used in half doses. beta-D-Glucan and D-arabinitol in the sera of patients were measured to document mycotic infections, and bacterial examinations were also performed. The efficacy of the combination therapy was 60.0% (18/30) and that of 5-FC alone was 65.5% (19/29). The stratified evaluation indicated that no factor was found to contribute to the efficacy in the two treatments with statistical significance. The side effects occurred in few cases and none of those was serious; including, one case of subjective symptom in each groups and two episodes of liver dysfunction in combination treatment. Changes in beta-D-glucan concentrations in the sera reflected well the pathophysiology of mycotic infections and clinical improvement. These results suggested that a combination of 5-FC and FLCZ at half doses provided a clinical benefit comparable to 5-FC alone at the ordinary dose, and the safety was considered satisfactory.

Adult↗
PubMed1993

pp60src is an endogenous substrate for calpain in human blood platelets.

Calpain is distributed ubiquitously in virtually every tissue (Croall, D. E., and DeMartino, G. N. (1991) Physiol. Rev. 71, 813-846), but its physiological role remains to be determined. The identification of its natural endogenous substrates would be of great interest. Since pp60src, a major tyrosine kinase in platelets, is known to be easily cleaved during purification from cells (Feder, D., and Bishop, J. M. (1990) J. Biol. Chem. 265, 8205-8211), we examined the possibility that it is an endogenous substrate of calpain. In the whole cell lysate from resting platelets, which was analyzed by Western blotting with monoclonal antibody 327, we found pp60src almost exclusively in a 60-kDa form, with a trace of 52-kDa form. Addition of A23187 (a calcium ionophore) or dibucaine, which are known to be activators of platelet calpain (Croall and DeMartino, 1991; Fox, J. E., Reynolds, C., Morrow, J. S., and Phillips, D. R. (1987) Blood 76, 2510-2519; Fox, J. E., Austin, C. D., Boyles, J. K., and Steffen, P. K. (1990b) J. Cell Biol. 111, 483-493), caused dose- and time-dependent cleavage of actin-binding protein and p235 protein (talin). At the same time, loss of the 60-kDa species of pp60src and generation of the 52-kDa (occasionally seen as doublets) and 47-kDa species were detected by the Western blotting. In platelets aggregated by 1 unit/ml thrombin, apparently identical cleavage products were found. The cleavage of pp60src was inhibited by calpeptin (20 microM), an inhibitor of calpain (Tsujinaka, T., Kajiwara, Y., Kambayashi, J., Sakon, M., Higuchi, N., Tanaka, T., and Mori, T. (1988) Biochem. Biophys. Res. Commun. 153, 1201-1208; Tsujinaka, T., Ariyoshi, H., Uemura, Y., Sakon, M., Kambayashi, J., and Mori, T. (1990) Life Sci. 46, 1059-1066; Fox, J. E., Clifford, C. C., and Austin, C. D. (1990) Blood 76, 2510-2519; Fox, J. E., Austin, C. D., Boyles, J. K., and Steffen, P. K. (1990) J. Cell. Biol. 111, 483-493; Fox, J. E., Austin, C. D., Clifford, C. C., and Steffen, P. K. (1991) J. Biol. Chem. 266, 13289-13295). Addition of EGTA (3 mM) to the extracellular media completely inhibited the cleavage of actin-binding protein, talin, and pp60src in response to A23187 (1 microM). Intact pp60src was distributed in both cytosolic and particulate (membrane) fractions. Cleaved species were found exclusively in the cytosolic fraction. pp60src-associated enolase kinase activity was reduced. Thus, pp60src is an endogenous substrate for calpain, the cleavage of which may have regulatory effects on the kinase.

Antibodies, Monoclonal↗
PubMed1993

Stimulation of human platelet Ca(2+)-ATPase and Ca2+ restoration by calpain.

To clarify the possible role of calpain (calcium activated neutral protease; EC 3.4.22.17) in Ca2+ homeostasis of human platelets, we investigated the effects of cell permeable calpain inhibitors, calpeptin and E-64d (EST), on the restoration of cytoplasmic Ca2+ ([Ca2+]i) in both Fura-2 and aspirin (ASA) loaded platelets. Although neither calpeptin (30 microM) nor EST (250 microM) altered the increase of [Ca2+]i in thrombin (1 U/ml) stimulated platelets, both calpain inhibitors delayed the decrease of [Ca2+]i back towards the basal level. These observations suggested that calpain might be involved in Ca2+ restoration. Then, the activity of Ca(2+)-ATPase was examined in thrombin (2 U/ml) stimulated platelets. Thrombin produced a rapid rise in Ca(2+)-ATPase activity by 2-fold at 8 s of incubation, which then returned to below the basal activity within 2 min. Calpeptin inhibited transient Ca(2+)-ATPase activation induced by thrombin in a dose related manner. Ca(2+)-ATPase of isolated platelet membranes was digested by purified human platelet calpain-I and Ca(2+)-ATPase activity was investigated. With a short incubation (8-15 s), Ca(2+)-ATPase activity was increased about 2-fold and then it decreased below the basal level at longer incubations or at a higher calpain/membrane ratio. The initial rate of Ca2+ uptake was also increased by about 2-fold with a short incubation (8-15 s). For molecular characterization of the Ca(2+)-ATPase, the formation of the enzyme-phosphate complex (EP) was investigated. The membrane bound intact 105 kD Ca(2+)-ATPase was converted by calpain to a fragment of approximately 50 kD.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspirin↗
PubMed1993

Translocation of human platelet calpain-I.

Intracellular localization of calpain (calcium dependent cysteine proteinase) was studied in resting or activated human platelets. When stimulated with 2 U/ml thrombin, approximately 40% of total cellular calpain activity and 25% of antigen translocated mainly to the intracellular membrane fractions with autolytic activation. Translocation of calpain was completely abolished by the addition of EDTA to the sonication medium. However an endogenous calpain inhibitor (calpastatin) activity was not detected in the membrane fractions both in resting and in thrombin stimulated platelets. Translocation of calpain was also observed in the platelets stimulated with ionomycin, collagen or phorbor myristate acetate (PMA). These data suggest that cytosolic calpain reversibly translocates to the intracellular membranes during platelet activation without an interference by calpastatin.

Blood Platelets↗