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H Morikawa

Publications and source records attributed to H Morikawa.

At least 73 records · Page 4Linked to original sources
PubMed1998

Adaptations to chronic agonist exposure of mu-opioid receptor-expressing Chinese hamster ovary cells.

To investigate cellular adaptation responses induced by chronic agonist treatment of the mu-opioid receptor, Chinese hamster ovary (CHO) cells were stably transfected with the rat mu-opioid receptor cDNA. Chronic treatment with agonists selective for the mu-opioid receptor, [D-Ala2, N-MePhe4, Gy-ol5]enkephalin (DAMGO), morphine and fentanyl, time- and dose-dependently induced down-regulation of the mu-opioid receptor. The down-regulation was not significantly affected by pretreatment with pertussis toxin, but was completely blocked by treatment with hypertonic sucrose, suggesting that receptor internalization mediated by clathrin-coated vesicles is an essential step in the mu-opioid receptor down-regulation. On the other hand, forskolin-stimulated cyclic AMP formation was increased by chronic DAMGO treatment, which was inhibited by pertussis toxin pretreatment. These results indicate that two adaptation responses induced by chronic agonist treatment of the mu-opioid receptor-expressing CHO cells, down-regulation of the mu-opioid receptor and supersensitization of adenylate cyclase, are mediated by distinct mechanisms.

Animals↗
PubMed1998

Tyrosine kinase inhibitors suppress N-type and T-type Ca2+ channel currents in NG108-15 cells.

Modulation of Ca2+ channel activity by protein kinases constitutes one of the major mechanisms regulating neuronal functions. Here, we explored the possible modulation of neuronal Ca2+ channels by protein tyrosine kinases (PTKs). To this end, the effects of PTK inhibitors on whole-cell Ba2+ currents (IBa) through voltage-gated Ca2+ channels were analysed in differentiated NG108-15 neuroblastoma x glioma hybrid cells. Genistein suppressed IBa in a concentration-dependent fashion (IC50 = 22 microM). Although daidzein, an analogue of genistein that is devoid of PTK inhibitory activity, also suppressed IBa, we estimated that specific PTK inhibition by genistein reduced IBa amplitude by 30%. In addition, lavendustin A (20 microM) and herbimycin A (20 microM), two other distinct PTK inhibitors, depressed IBa by 22% and 20%, respectively. Genistein suppressed N-type and T-type currents, sparing L-type current, and its effect was independent of G protein activation. The results suggest that the activity of neuronal Ca2+ channels can be modulated by PTKs, opening the possibility that some of the functions of PTKs in the nervous system are mediated by Ca2+ channel modulation.

Animals↗
PubMed1998

Enhancement by stem cell factor of interleukin-2 (IL-2)-induced DNA synthesis in human decidual CD16- CD56bright natural killer cells mediated by increased expression of the IL-2 receptor alpha chain.

Extracts of chorionic villous and decidual tissue specimens from women in the early stages of pregnancy contained stem cell factor (SCF), the amount in the latter tissue (246.6+/-119.7 pg/mg protein) being approximately three times that in the former. Immunohistochemical analysis revealed the presence of SCF in the mesenchymal cells of the chorion, the trophoblast, and decidual stromal cells, whereas the SCF receptor, c-kit, was detected in the trophoblast and decidual mononuclear leukocytes but not in decidual stromal cells. Reverse transcription and polymerase chain reaction analysis detected transcripts corresponding to both secretory and membrane-bound types of SCF in chorionic tissue, but only those encoding the secretory type in decidual tissue. Flow cytometric analysis showed that c-kit was expressed on decidual CD16- CD56bright natural killer (NK) cells, CD14+ macrophages, and CD34+ hematopoietic progenitor cells, but not on CD3+ T cells or CD16+ NK cells. Although SCF alone had no effect on DNA synthesis in decidual CD16- CD56bright NK cells, it enhanced the proliferative effect of interleukin-2 (IL-2) at IL-2 concentrations that selectively saturate the high-affinity IL-2 receptor (IL-2R). Flow cytometry of decidual mononuclear leukocytes cultured in the presence of SCF demonstrated that this factor increased the expression of the IL-2Ralpha chain, but not IL-2Rbeta and gamma chain expression on CD16- CD56bright NK cells. Results suggest that SCF produced in the decidua increases the expression of the IL-2Ralpha which is usually present in smaller amounts than other two IL-2R chains on decidual CD16- CD56bright NK cells, and thereby promotes the proliferation of these cells in response to low concentrations of IL-2, resulting in an increase of the high affinity IL-2Rs.

CD56 Antigen↗
PubMed1998

A novel evaluation system of metastatic potential of oral squamous cell carcinoma according to the histopathological and histochemical grading.

We established a new evaluation system for metastatic potential of oral squamous cell carcinoma (SCC), utilizing a combined examination of histopathological grades of the carcinomas based on cell differentiation and invasive mode according to Yamamoto's criteria, and the cellular expressions of CD44, E-cadherin (E-cad), heparan sulfate glycosaminoglycan (HS-GAG) and Phaseolus vulgaris leukoagglutinin (L-PHA)-binding oligosaccharides on the carcinomas. Histochemical patterns of expression of these markers were classified into positive (+2), weakly positive (+), and negative (-). The histopathological grades and the histochemical patterns of the SCC were estimated on a 0-2 point scale, i.e. point 2 for poorly differentiated, mode 4D, CD44++, E-cad-, HS-GAG++, or L-PHA++; point 1 for moderately differentiated, mode 4C, CD44+, E-cad+, HS-GAG+, or L-PHA+; and point 0 for well differentiated, mode 1, mode 2, mode 3, CD44-, E-cad++, HS-GAG-, or L-PHA-. As a result, incidence of metastasis in the cases with a total score of more than 6 (62.8%) was significantly higher than that with a total score of less than 5 (9.3%). This evaluation system will yield useful information concerning the prognosis of patients with oral SCC.

Biomarkers, Tumor↗
PubMed1998

Desensitization and resensitization of delta-opioid receptor-mediated Ca2+ channel inhibition in NG108-15 cells.

1. To approach the mechanisms underlying desensitization of the opioid receptor-mediated Ca2+ channel inhibition, the effects of prolonged application of [D-Ala2, D-Leu5]enkephalin (DADLE) on Ba2+ currents (I(Ba)) through Ca2+ channels were analysed in NG108-15 neuroblastoma x glioma hybrid cells. 2. Inhibition of I(Ba) by 100 nM DADLE desensitized by 57% with a time constant of 4.4 min. 3. Maximal desensitization of the delta-opioid receptor-Ca2+ channel coupling was attained by 1 microM DADLE. The EC50 value for desensitization was estimated to be 78 nM. 4. RNA blot hybridization analysis and immunoblot analysis revealed the expression of beta-adrenoceptor kinase-1 (betaARK1) in NG108-15 cells. 5. Heparin, an inhibitor of betaARK, significantly reduced the magnitude and rate of desensitization, whereas Rp-cyclic AMPS and PKI (14-24)amide, inhibitors of cyclic AMP-dependent protein kinase (PKA), or long-term treatment with phorbol 12-myristate 13-acetate to induce down-regulation of protein kinase C (PKC) had no significant effect. 6. Recovery from desensitization (resensitization) proceeded with a time constant of 6.7 min. Okadaic acid, an inhibitor of serine/threonine phosphatases 1 and 2A, significantly attenuated the degree of resensitization. 7. In summary, we have characterized the time course and concentration-dependence of the desensitization of DADLE-induced I(Ba) inhibition in NG108-15 cells. This desensitization was reversible after removal of DADLE. It is suggested that betaARK, but neither PKA nor PKC, is involved in desensitization, while serine/threonine phosphatases mediate resensitization.

Animals↗
PubMed1998

Activation of phospholipase A2 by the nociceptin receptor expressed in Chinese hamster ovary cells.

To gain insight into the molecular mechanism for nociceptin function, functional coupling of the nociceptin receptor expressed in Chinese hamster ovary (CHO) cells with phospholipase A2 (PLA2) was examined. In the presence of A23187, a calcium ionophore, activation of the nociceptin receptor induced time- and dose-dependent release of arachidonate, which was abolished by pretreatment of the cells with pertussis toxin (PTX). Immunoblot analysis using anti-Ca2+-dependent cytosolic PLA2 (cPLA2) monoclonal antibody demonstrates that activation of the nociceptin receptor induces a time- and dose-dependent electrophoretic mobility shift of cPLA2, suggesting that phosphorylation of cPLA2 is induced by the nociceptin receptor. Pretreatment of the cells with PD98059, a specific mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1 inhibitor, or staurosporine, a potent inhibitor of serine/threonine protein kinases and tyrosine protein kinases, partially inhibited the nociceptin-induced cPLA2 phosphorylation and arachidonate release. These results indicate that the nociceptin receptor expressed in CHO cells couples with cPLA2 through the action of PTX-sensitive G proteins and suggest that cPLA2 is activated by phosphorylation induced by the nociceptin receptor via mechanisms partially dependent on p44 and p42 mitogen-activated protein kinases.

Animals↗
PubMed1998

A case of congenital mumps infection complicated with persistent pulmonary hypertension.

A low-birth-weight female baby was admitted with respiratory distress after birth. Her mother had been diagnosed with mumps 4 weeks and 5 days prior to delivery. Mumps IgM antibody was elevated in the neonate and mumps virus ribonucleic acid was detected in the umbilical cord blood by reverse transcription-polymerase chain reaction. The perinatal virus infection was complicated with persistent pulmonary hypertension of the newborn and pulmonary hemorrhage. Successful treatment included the use of high frequency oscillation ventilation together with the administration of artificial surfactant.

Antibodies, Viral↗
PubMed1998

Partial agonistic activity of naloxone on the opioid receptors expressed from complementary deoxyribonucleic acids in Chinese hamster ovary cells.

UNLABELLED: Naloxone is a widely used opioid antagonist. To analyze the cellular responses induced by naloxone in the absence of opioid agonists, Chinese hamster ovary (CHO) cells, which do not endogenously express the opioid receptors, have been permanently transfected with the cloned complementary DNAs to produce the mu-, delta-, and kappa-opioid receptors. Naloxone dose-dependently reduced forskolin-stimulated cyclic adenosine monophosphate (cAMP) formation in the cells expressing the mu- and kappa-opioid receptors, although the effect was less than that of opioid agonists [D-Ala2, N-Me-Phe4, Gly-ol5]enkephalin and U50,488, respectively. The naloxone-induced cAMP reduction was abolished by pretreatment of the cells with pertussis toxin, which suggests that pertussis toxin-sensitive G proteins (Gi and/or Go) are involved in the response. Cellular guanosine triphosphatase activity was significantly increased by naloxone in the cells expressing the mu- and kappa-opioid receptors, which suggests that the application of naloxone to these receptors induces activation of the G proteins. We conclude that naloxone possesses partial agonistic activity on the mu- and kappa-opioid receptors expressed from complementary DNAs in CHO cells. IMPLICATIONS: In this study, we examined whether naloxone has agonistic activity on the opioid receptors by using cultured cells transfected with delta-, mu-, and kappa-opioid receptor complementary DNAs. Our data indicate that naloxone is a partial agonist on the mu- and kappa-opioid receptors.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1998

Hepatocyte growth factor in human breast milk.

PROBLEM: The purposes of this study were to investigate the presence of hepatocyte growth factor (HGF) in human milk, to identify the cells that produce HGF in human milk, and to determine the contribution of HGF to the growth of neonates. METHOD OF STUDY: The HGF concentrations in serum and whey were determined with an enzyme-linked immunosorbent assay kit. The presence of HGF in whey was also examined by Western blot analysis. To determine which cells in human milk produce HGF, an immunohistochemical examination was conducted. The expression of HGF mRNA in the mononuclear cells in human milk was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The effects of whey and of recombinant HGF (rHGF) on DNA synthesis by a rat small intestinal cell line, IEC-6, were examined by [3H]thymidine uptake. RESULTS: Human colostrum whey contained 2.22 +/- 1.02 ng of HGF/ml. Milk whey collected 1 month later contained 1.83 +/- 1.03 ng of HGF/ml. The presence of the heterodimeric form of HGF in colostrum whey was demonstrated by Western blot analysis. HGF was detected in the cytoplasm of human milk macrophages by an immunohistochemical examination, and the RT-PCR also revealed that HGF mRNA is expressed in the mononuclear cells of human milk. DNA synthesis by IEC-6 cells was increased by rHGF treatment and by whey treatment. The effect of whey on DNA synthesis by IEC-6 cells was partially, but significantly, decreased by anti-human HGF-neutralizing antibody treatment. CONCLUSIONS: Human milk contains a large amount of the active form of HGF, produced by macrophages, and HGF in human milk induces the growth of intestinal cells. Our data suggest that HGF in human milk is one of the important factors regulating the growth of intestinal cells in neonates after birth.

Adult↗
PubMed1998

[A case of primary localized amyloidosis of the urinary bladder].

A case of primary amyloidosis of the bladder is reported. A 59-year-old man visited our hospital with a complaint of gross hematuria. Cystoscopy revealed several elevated lesions with yellowish surface accompanied by proliferated vessels at the posterior wall. Transurethral mucosal biopsy was performed. Histopathological diagnosis was a primary localized amyloidosis of AL type in the bladder. Systemic amyloidosis was clinically excluded. He is followed for 38 months without symptoms but mucosal lesions persisted.

Amyloidosis↗
PubMed1997

Ca2+ channel inhibition by endomorphins via the cloned mu-opioid receptor expressed in NG108-15 cells.

Endomorphin-1 and -2, recently isolated endogenous peptides specific for the mu-opioid receptor, inhibited Ca2+ channel currents with EC50 of 6 and 9 nM, respectively, in NG108-15 cells transformed to express the cloned rat mu-opioid receptor. On the other hand, they elicited no response in nontransfected NG108-15 cells. It is concluded that endomorphin-1 and -2 induce Ca2+ channel inhibition by selectively activating the mu-opioid receptor.

Analgesics, Opioid↗
PubMed1997

Activation of mitogen-activated protein kinase by the nociceptin receptor expressed in Chinese hamster ovary cells.

Activation of the nociceptin receptor stably expressed in Chinese hamster ovary cells induced a transient mitogen-activated protein kinase (MAPK) activation, via pertussis toxin-sensitive G-proteins. The nociceptin receptor-mediated MAPK activation was partially blocked by down-regulation or inhibition of protein kinase C, and suppressed by pretreatment with a phosphatidylcholine-specific phospholipase C inhibitor, D609. Furthermore, a tyrosine protein kinase inhibitor, genistein, and phosphatidylinositol 3-kinase inhibitors, wortmannin and LY294002, affected the nociceptin-induced MAPK activity. The nociceptin-induced MAPK activation may lead to activation of phospholipase A2 and induce changes in gene expression.

Androstadienes↗
PubMed1997

Functional expression on human trophoblasts of interleukin 4 and interleukin 7 receptor complexes with a common gamma chain.

The gamma chain in the high-affinity receptor complex for interleukin 2(IL-2) is used in receptor complexes for IL-4 and IL-7. We examined expression and function of the gamma chain in trophoblast cells. Flow cytometric studies demonstrated that the human placental cell line and choriocarcinoma cell lines expressed the IL-2R gamma chain. None of these cell lines expressed the IL-2R alpha and beta chains, whereas the alpha chains of IL-4R and IL-7R were present. The gamma chain and IL-4R and IL-7R mRNA were detected in human placental trophoblasts by the in situ hybridization method. The release of human chorionic gonadotropin by trophoblasts was accelerated by IL-4 and IL-7 in a concentration-dependent manner. These findings indicate that IL-4 and IL-7 are involved in trophoblast function.

Antigens, CD↗
PubMed1997

Diagnosis of chronic liver disease from liver scintiscans by artificial neural networks.

Artificial neural networks were used in the diagnosis of chronic liver disease based on liver scintiscanning. One hundred and thirty-seven patients with chronic liver disease (12 with chronic persistent hepatitis, 39 with chronic aggressive hepatitis, and 86 with cirrhosis) and 25 healthy controls were studied. Sixty-five subjects (10 healthy controls, 20 patients with chronic hepatitis, and 35 patients with cirrhosis of the liver) were used in the establishment of a neural network. Liver scintiscans were taken starting 20 min after the intravenous injection of 111 MBq of Tc-99m-phytate. The neural network was used to evaluate five items judged from information on liver scintiscans: the ratio of the sizes of the left and right lobes, splenomegaly, radioactivity in the bone marrow, deformity of the liver and distribution of radioactivity in the liver. The neural network was designed to distinguish between three liver conditions (healthy liver, chronic hepatitis and cirrhosis) on the basis of these five items. The diagnostic accuracy with the neural network was 86% for patients with chronic hepatitis and 93% for patients with cirrhosis. With conventional scoring, the accuracy was 77% for patients with chronic hepatitis and 87% for patients with cirrhosis. Our findings suggest that artificial neural networks may be useful for the diagnosis of chronic liver diseases from liver scintiscans.

Case-Control Studies↗
PubMed1997

Existence of three regulatory regions each containing a highly conserved motif in the promoter of plastid-encoded RNA polymerase gene (rpoB).

The plastid gene rpoB encodes a plastid-specific, DNA-dependent RNA polymerase. A study of a barley mutant, albostrians, indicated that rpoB itself is transcribed by a nuclear-encoded RNA polymerase. However, the molecular nature of the nuclear-encoded RNA polymerase and mechanisms of the transcriptional regulation of rpoB expression have not been elucidated. Using an in vivo transient assay system for gene expression in plastids, the 5'-flanking region of rpoB from Arabidopsis thaliana in plastids of cultured BY-2 tobacco cells was analyzed. A series of deletion analyses of the 5'-flanking region indicated that there were two positive and one negative regulatory regions for rpoB expression. Comparison of the 5'-flanking sequences of rpoB among several plant species revealed the existence of three conserved motifs in these regions.

Arabidopsis↗
PubMed1997

Effect of SDZ PSC 833 ([3'-keto-Bmt1]-[Val2]-cyclosporin) on serum protein binding and distribution to blood cells of doxorubicin, vincristine and etoposide in vitro.

SDZ PSC 833 ([3'-keto-Bmt1]-[Val2]-cyclosporin) is a P-glycoprotein-mediated multidrug resistance modulator currently undergoing clinical trials. SDZ PSC 833 modulates not only antitumor activity but also tissue distribution of doxorubicin in mice. Since protein binding in plasma/serum and distribution to blood cells are important factors affecting the tissue distribution and excretion of drugs, we investigated the effect of SDZ PSC 833 on serum protein binding and distribution to blood cells of doxorubicin, vincristine and etoposide in vitro. Unbound fractions in serum and fractions distributed to blood cells of either [14C]doxorubicin, [3H]vincristine or [3H]etoposide were determined using serum and blood obtained from mice and healthy volunteers. Effects of SDZ PSC 833 at 3 microg/ml, which was an achievable concentration in a clinical trial of SDZ PSC 833, on protein binding and distribution of the drugs to blood cells were negligible in mouse and human blood in vitro. The absence of interaction between PSC 833 and the anticancer drugs in protein binding and distribution to blood cells suggested the existence of other mechanisms. Possible interactions are speculated to be inhibition of P-glycoprotein function contributing to drug excretion and tissue distribution and inhibition of drug metabolism mediated by cytochrome P450 3A.

Animals↗
PubMed1997

[Inhibition of 5-fluorouracil-cisplatin-induced stomatitis by oral cryotherapy: use of an ice-bar containing fibrinolysin and deoxyribonuclease combine (Elase)].

Stomatitis caused by a combined chemotherapy with 5-fluorouracil (5-FU) and cisplatin (CDDP) is a serious problem in the course of treatment for patients with oral carcinoma. In the present study, we proposed a form of cryotherapy using an ice-bar containing fibrinolysin and deoxyribonuclease (Elase) to inhibit the stomatitis. The therapeutic effect of the ice-bar cryotherapy was evaluated in 20 patients with oral squamous cell carcinoma who were undergoing 5-FU-CDDP chemotherapy. Nine of the 20 patients were given the ice-bar cryotherapy while the remaining patients were not. As a result, although there was no significant difference between the incidence of stomatitis in the groups with and without the ice-bar cryotherapy, the incidence of severe stomatitis with ulcers and/or eating disturbance in the 11 cases without the ice-bar cryotherapy (90%) was significantly higher than that in the 9 cases with the cryotherapy (44%) (p < 0.05). However, no significant difference in the clinical response rate of the 5-FU-CDDP chemotherapy was observed between the two groups.

Adult↗