Biomedical subjects

S Hirota

Publications and source records attributed to S Hirota.

At least 163 records · Page 9Linked to original sources

PubMed1995

Identification of the cells expressing cot proto-oncogene mRNA.

The cell types expressing cot proto-oncogene mRNA were identified by in situ hybridization (ISH) histochemistry. Among a variety of adult mouse tissues examined, four types of glandular cells expressing cot gene were identified: (1) granular duct cells in the submandibular and sublingual glands; (2) serous cells in the parotid gland; (3) peptic (chief) cells in gastric glands; and (4) goblet cells in colonic glands. Investigation of the developmentally regulated expression of cot mRNA using tissues of 14-day and 18-day embryos, newborn and weanling mice showed that cot gene is expressed only in morphologically differentiated and functionally activated cells of these four types. No other types of cells showing ISH signals were observed. Based on these results, cot gene expressions in cultured cells of colonic adenocarcinomas and gastric adenocarcinomas were examined. SW 480 and WiDr cells showed high expression of this gene and so should be useful for functional analysis of Cot kinase. The expression patterns of cot gene in tumor tissues of the parotid gland, and gastric and colonic glands were investigated. Two of the tissues overexpressed this gene markedly, suggesting that overproduction of Cot kinase may be one cause of their transformation.

Adenocarcinoma↗

PubMed1995

Glucocorticoids induce mineralization coupled with bone protein expression without influence on growth of a human osteoblastic cell line.

Mineralization was induced by glucocorticoid treatment in a human osteoblastic cell line derived from normal bone in vitro, designated SV-HFO, immortalized with simian virus 40 (CHIBA, H. et al. (1993). Jpn. J. Cancer Res., 84: 290-297). Mineralization was revealed by electron microscopy, von Kossa staining and electron spectroscopic analysis, which indicated that the Ca/P ratio was approximately 1.70, corresponding to the value of hydroxyapatite. The effect was dose- (10(-8)-10(-6) M) and time-dependent (days 7-28), was greatest at day 28, and was preceded by expression of alkaline phosphatase (ALP) and osteopontin (OPN). The ALP activity induced was highest at day 7, whereas OPN reached its highest level at day 28. When the induction of ALP activity was inhibited by 10(-4) M levamisole, mineralization of SV-HFO cells by glucocorticoid treatment was markedly reduced, suggesting that elevated ALP activity in the early phase is important in the mineralization of human osteoblastic cells. Glucocorticoid treatment did not alter cell proliferation. These results indicated that glucocorticoids play crucial roles in the formation of mineralized matrix in human osteoblasts by inducing differentiation of SV-HFO cells without modulating their proliferative activity.

Alkaline Phosphatase↗

PubMed1995

Caffeine enhances adriamycin antitumor activity in Ehrlich ascites carcinoma-bearing mice.

We examined whether caffeine enhances the antitumor activity of adriamycin (ADR), in terms of prolonging survival in Ehrlich ascites carcinoma(ascites-type)-bearing mice. After administration of ADR at a dose of 0.5 mg/kg/d for 5d together with caffeine (100 mg/kg/d x 5 d), the survival period was increased by 39%. However, caffeine had little effect on this ADR induced-prolongation of survival following administration of ADR at 2.0 mg/kg/d for 4 d. Although a significant increase in ADR concentration in the ascites tumor was seen after administration of ADR at a dose of 0.5 mg/kg, caffeine failed to increase ADR concentration in the ascites tumor after administration of ADR at a dose of 2.0 mg/kg. The effect of caffeine thus appears to be due to its effect on the tumor distribution of ADR.

Animals↗

PubMed1995

I-123 metaiodobenzylguanidine cardiac scintigraphy in patients with an implanted permanent pacemaker.

T1 scintigraphic abnormalities have been reported in patients with an implanted permanent pacemaker, but little is known about the MIBG scintigraphic findings in such patients. This study was performed to assess the MIBG scintigraphic findings in patients with an implanted permanent pacemaker, and to test the hypothesis that imaging characteristics of MIBG scintigraphy differ according to its mode. Twelve patients (4 men and 8 women, mean age: 72.4 +/- 9.5 years), who had undergone the implantation of a permanent pacemaker for bradyarrhythmias, underwent MIBG scintigraphy. The patients were divided into VVI pacemaker and DDD pacemaker groups. The tomograms were divided into nine segments and the MIBG defect in each segment scored on a scale ranging from 0 (normal uptake) to 3 (no uptake). Total MIBG defect scores were generated by summing the scores for the nine segments in each patient. MIBG scintigraphic abnormalities were found in ten of the twelve patients. The six patients with the VVI pacemaker manifested MIBG scintigraphic abnormalities. These MIBG scintigraphic abnormalities were observed in all segments, particularly in the posterior segments. The mean total defect score of the VVI group was higher than that of the DDD group (14.8 +/- 9.8 vs 3.0 +/- 3.5, respectively p < 0.05). Therefore, we conclude that despite several limitations of the study, MIBG scintigraphic abnormalities occur in patients with implanted permanent pacemakers, and that such abnormalities are more prominent with the VVI than DDD pacemaker.

3-Iodobenzylguanidine↗

PubMed1995

The effect of dose on the distribution of adriamycin encapsulated in polyethyleneglycol-coated liposomes.

The distribution of adriamycin (ADR) at a clinically relevant low dose of 2.5 mg/kg was compared to the distribution at a high dose of 7.5 mg/kg (dose often employed in distribution studies). ADR solution (ADRsol), plain liposomal ADR (PLADR) and polyethyleneglycol (PEG)-coated liposomal ADR (PEG-LADR) were injected into the tail vein of Wistar rats. The retention in serum was PEG-LADR > PLADR > ADRsol at both doses. In the high-dose study, ADR concentration in the liver and spleen at 4 h after administrations of PLADR and PEG-LADR were higher than that with ADRsol. On the other hand, in the low-dose study, reticuloendothelial system (RES) uptake of ADR was reduced by liposome encapsulation (liposomalization). Reduced ADR concentrations in the heart due to liposomalization were found only at the low doses. These results indicate that the difference in doses led to different distributions and that there is an optimal dose at which liposomes exhibit their objective distribution. A comparison of the ADR concentration in the spleen to that in the liver indicated RES saturation by increasing doses and the optimal dose being lower than the dose that saturates RES. Thus, distribution of liposome-entrapped ADR must be investigated at doses as close to the clinical dose as possible.

Animals↗

PubMed1995

Determination of the thickness of the fixed aqueous layer around polyethyleneglycol-coated liposomes.

The zeta potentials of adriamycin-encapsulating liposomes containing 1-(monomethoxy polyethyleneglycol)-2,3-dimyristoylglycerol (PEG-DMG) were measured in an isotonic solution of 10mM lactate buffer (pH 4.0) with sodium chloride and sucrose. The negativity of the zeta potentials of adriamycin-encapsulating liposomes containing PEG-DMG decreased with increases in NaCl concentration more steeply than that of adriamycin-encapsulating liposomes without PEG coating. From this observation, the electrical potential distributions near the membrane surfaces were shown to be different between adriamycin-encapsulating liposomes with and without PEG coating. Based on these zeta potential data, the thickness of the fixed aqueous layer around PEG-DMG-containing adriamycin liposomes was determined from the slope of 1n zeta potential versus Debye-Hückel parameter plot. As a result, a correlation was indicated to exist between the circulation time of liposomes and the thickness of the aqueous layer around the liposomes.

Chemistry, Pharmaceutical↗

PubMed1995

Feeding of palm oil carotene to mice did not modify X-ray-induced chromosomal damage in bone marrow cells.

The influence of palm oil carotene treatment on X-ray-induced chromosomal damage in bone marrow cells of mice was studied. Palm oil carotene contains alpha- and beta-carotene in a ratio of 1:3. Mice were fed either a basal diet or carotene diet containing 50 mg of palm oil carotene/100 g for 15 days. On day 13, mice to be X-ray-irradiated received 0.5 Gy of X-ray to their whole bodies, and the chromosomal damage in bone marrow cells was evaluated in terms of the percentages of micronucleated reticulocytes in their peripheral blood on day 15. The chromosomal damage in the X-ray irradiated mice was 10 times higher than that in the unirradiated mice. The feeding of the carotene diet did not prevent the X-ray-induced chromosomal damage. In the bone marrow cells of mice fed the carotene diet, alpha- and beta-carotene were detected, but the concentration of the carotenes was less than one-hundredth of that of vitamin E. In addition, the feeding of carotene diet markedly reduced the concentration of vitamin E in bone marrow cells and serum. The X-ray irradiation reduced the concentration of vitamin C in the bone marrow cells, but did not reduce that of vitamin E or carotene in the cells.

Animals↗

PubMed1995

Enhanced expression of CD34 messenger RNA by developing endothelial cells of mice.

BACKGROUND: Immunohistochemical studies have demonstrated that CD34 antigen is present on the surface of vascular endothelial cells and hematopoietic cells. Roles of CD34 for angiogenesis and its function as a homophilic adhesion molecule between endothelial and hematopoietic cells have been speculated. EXPERIMENTAL DESIGN: Northern blotting was used to examine the expression levels of CD34 mRNA, and in situ hybridization was used to localize CD34 mRNA. First, we investigated changes in CD34 mRNA expression in developmental processes of mice. Second, we investigated the changes in skin tissues of adult mice in the process of wound healing and tumor growth. RESULTS: CD34 mRNA was strongly expressed by most of the vascular endothelial cells in developing organs. The magnitude of the expression decreased after birth but increased again in the process of wound healing and tumor growth. Although CD34 mRNA signals were observed in hematopoietic cells in the yolk sac and fetal liver, the endothelial cells of these tissues did not express CD34 mRNA signals. CD34 mRNA signals were detectable in neither hematopoietic nor endothelial cells of the bone marrow. In tissues other than hematopoietic ones, however, blood cells within the vessels did not express CD34 mRNA, although the endothelial cells expressed CD34 mRNA. CONCLUSIONS: The expression pattern of CD34 mRNA suggested its significant role in development of blood vessels not only in embryos but also in adults. Although CD34 mRNA was expressed both by endothelial cells and hematopoietic cells, the expression did not occur within the same organ, suggesting that the CD34 molecule may not be used as a homophilic adhesion molecule between endothelial and hematopoietic cells.

Animals↗

PubMed1995

Expression of osteopontin messenger RNA in the rat kidney on experimental model of renal stone.

We investigated the expression of osteopontin (OPN) messenger (m) RNA in the rat kidney under the experimental models of several conditions that are considered to be risk factors of human renal stones. In the renal stone formation model administrated glyoxylic acid and 1,25-dihydroxyvitamin D3, pyelonephritis model and hydronephrosis model the expression of OPN mRNA in the distal convoluted tubule of the kidney was enhanced compared with the control which was sporadically positive utilizing in situ hybridization and northern blot analysis. The expression of OPN mRNA was markedly inhibited in the renal stone formation model by concominant administration of estradiol and/or progesterone.

Animals↗

PubMed1995

Mechanisms of eosinophilia in mice infested with larval Haemaphysalis longicornis ticks.

Infestation of larval Haemaphysalis longicornis ticks induced a threefold increase of eosinophils in the peripheral blood of normal WBB6F1- +/+ mice 2 days after tick infestation. In genetically mast cell-deficient WBB6F1- W/Wv mice, a threefold increase of blood eosinophils was observed 6 days after the tick infestation. However, marked infiltration of eosinophils was detected in the tick infestation sites of the WBB6F1- +/+ mice but not the WBB6F1- W/Wv mice. When the mast cell deficiency of WBB6F1- W/Wv mice had been rescued locally by intradermal injections of WBB6F1- +/+ mouse-derived cultured mast cells, a rapid increase of blood eosinophils and tissue infiltration of eosinophils were revealed following tick infestation. The intravenous (i.v.) injection of immune spleen or lymph node cells obtained from WBB6F1- +/+ mice 10 days after tick infestation led to significant eosinophilia in naive recipient mice. Treatment with anti-Thy-1.2 or anti-CD4 monoclonal antibody (mAb) and complement (C) completely abolished the eosinophilia; the early response (2 days after tick challenge) is dependent on mast cells at the feeding site, and the late response (6 days after tick challenge) is dependent on T lymphocytes. Since amplified interleukin-5 (IL-5) cDNA was detectable in the spleen cells 4 days after tick infestation, the late response might be mediated by IL-5. The infiltration of eosinophils at the feeding site of skin appeared to be dependent on mast cells.

Animals↗

PubMed1995

Expression of bone matrix protein messenger ribonucleic acids in human breast cancers. Possible involvement of osteopontin in development of calcifying foci.

BACKGROUND: Development of calcifying foci is a fairly common finding in human breast cancers, and the deposition of calcium phosphate is observed in such foci. The calcium phosphate is a physiologic component of bones and teeth. Since the expression of messenger (m) RNAs of osteopontin (OPN), osteocalcin (OC), osteonectin (ON), and matrix gla protein (MGP) has been described in bones and teeth, we examined the mRNA expression of OPN, OC, ON, or MGP in the calcifying foci that were observed in human breast cancers. EXPERIMENTAL DESIGN: Cell types expressing mRNAs of OPN, ON or MGP were identified with combination of in situ hybridization and immunohistochemistry. RESULTS: The OPN mRNA-expressing cells clustered around the necrotic foci within cancer cell nests, and the examination with anti-OPN antibody revealed that OPN protein was localized in such necrotic foci where calcium phosphate deposited. The OPN mRNA-expressing cells were identified as macrophages by staining the adjacent section with the anti-CD68 PG-M1 monoclonal antibody which specifically recognizes macrophages. Neither ON mRNA-expressing cells nor MGP mRNA-expressing cells appeared to correlate with the deposition of calcium phosphate. CONCLUSIONS: The OPN protein produced by macrophages appeared to play a significant role for development of calcifying foci within necrotic area of breast cancers.

Antibodies, Monoclonal↗

PubMed1995

Expression of vascular endothelial growth factor and its receptor mRNA in angiosarcoma.

BACKGROUND: Vascular endothelial growth factor (VEGF), a specific mitogen for endothelial cells in vitro, can be angiogenic factor in vivo. VEGF is known to be produced by several tumor cells and plays an important role for neovascularization in tumor tissue. Recently, tyrosine kinase encoded by the flt gene was identified as a receptor for VEGF. Angiosarcoma (AS) is a rare malignant tumor that arises from endothelium. At present, little is known about a mechanism of proliferation of the AS. EXPERIMENTAL DESIGN: In an immunohistochemical study of 99 cases of AS, 11 cases showing a positive reaction for anti-VEGF Ab were selected for the present study. In these cases, expression of VEGF and its receptor (flt) mRNA was examined by in situ hybridization: sense and antisense probes for VEGF and flt mRNA were used. RESULTS: In situ hybridization study with antisense probes revealed that the VEGF mRNA was expressed in AS cells and mononuclear cells in all but one case. Intensity of VEGF staining by immunohistochemistry correlated well with VEGF mRNA expression. The flt mRNA was expressed in AS cells in all 10 cases that were positive for VEGF mRNA. Sense probe for VEGF and flt mRNA gave no positive reactions. CONCLUSIONS: These findings suggest a presence of paracrine or autocrine mechanism of proliferation in AS through VEGF and its receptor flt.

Aged↗

PubMed1994

Molecular structure of redox metal centers of the cytochrome bo complex from Escherichia coli. Spectroscopic characterizations of the subunit I histidine mutant oxidases.

A site-directed mutagenesis study on the conserved subunit I histidines of the cytochrome bo complex in Escherichia coli identified ligands of the low spin heme B and CuB centers; however, the assignment of the proximal ligand of the high spin heme O was ambiguous (Minagawa, J., Mogi, T., Gennis, R. B., and Anraku, Y. (1992) J. Biol. Chem. 267, 2096-2104). We have extended this work and characterized the metal centers in the purified histidine mutant oxidases by optical, EPR, and resonance Raman spectroscopies and by biochemical analysis. We found that the H284A and H333A oxidases contain two heme B molecules, which exhibit the gz = 2.99 low spin and cyanide-sensitive g perpendicular = 6 high-spin EPR signals, whereas the H419A oxidase contains only low spin heme B, which shows the gz component in a considerably higher magnetic field at g = 2.92. The CuB center was partially retained in the H284A oxidase but was almost completely lost in the H333A and H419A oxidases. Thus, we concluded that His419 is the proximal ligand of the high spin heme O and that His284 is located at the distal side of the high spin heme O. His284 plays an indispensable role in maintaining the structure of the Feo-CuB binuclear site suitable for the exogenous ligand bindings in the reduced state, since its substitution eliminated the CO binding activity. In addition, we found that His106 and His421 are in fact the axial ligands of the low spin heme B, although the H421A mutation perturbed the binuclear metal center seriously. Based upon experimental results with isotopic substitutions on iron in the oxidases, we assigned the Raman band at 208 cm-1 to the iron-histidine stretching mode (vFc(2+)-N(His)) of the wild-type ferrous cytochrome o, which was upshifted slightly by a loss of the CuB center in the H333A oxidase. A molecular structure of the metal centers and a possible mechanism of the electron transfer-coupled proton pumping in the cytochrome bo complex are proposed on the basis of our present findings.

Copper↗

PubMed1994

Poor response of cultured mast cells derived from mi/mi mutant mice to nerve growth factor.

Decreased numbers of mast cells and abnormalities in the phenotype of mast cells are observed in the skin of mi/mi mutant mice. Recently, the mi locus was identified to encode a novel member of the basic-helix-loop-helix-leucine zipper protein family of transcription factors. Since nerve growth factor (NGF) has been reported to influence the proliferation and the phenotype of cultured mast cells (CMCs), we compared the effect of NGF between mi/mi and control normal (+/+) CMCs. Addition of NGF to the suboptimal dose of recombinant murine interleukin-3 (rmIL-3) increased the plating efficiency of +/+ CMCs, but not of mi/mi CMCs. Although +/+ CMCs were berberine sulfate-negative when cultured with rmIL-3 alone, +/+ CMCs became berberine sulfate-positive when cultured in the presence of both rmIL-3 and NGF, which suggests increased heparin content. In contrast, NGF did not influence the phenotype of mi/mi CMCs. +/+ CMCs significantly bound 125I-NGF, but mi/mi CMCs did not, which suggests a defect of NGF receptors in mi/mi CMCs. Both p75 and p140 molecules are known to be involved in the formation of NGF receptors. Although the expression of p140 messenger (m)RNA was comparable between +/+ and mi/mi CMCs, the expression of p75 mRNA was significantly lower in mi/mi CMCs than in +/+ CMCs. Taken together, the poor response of mi/mi CMCs to NGF appeared to be attributable to the impaired transcription of the p75 gene.

Animals↗

PubMed1994

Observation of the Fe-O2 and FeIV=O stretching Raman bands for dioxygen reduction intermediates of cytochrome bo isolated from Escherichia coli.

Reaction intermediates in dioxygen reduction by the E. coli cytochrome bo-type ubiquinol oxidase were studied by time-resolved resonance Raman spectroscopy using the artificial cardiovascular system. At 0-20 microseconds following photolysis of the enzyme-CO adduct in the presence of O2, we observed the Fe-O2 stretching Raman band at 568 cm-1 which shifted to 535 cm-1 with the 18O2 derivative. These frequencies are remarkably close to those of other oxyhemoproteins including dioxygen-bound hemoglobin and aa3-type cytochrome c oxidase. In the later time range (20-40 microseconds), other oxygen-isotope-sensitive Raman bands were observed at 788 and 361 cm-1. Since the 781 cm-1 band exhibited a downshift by 37 cm-1 upon 18O2 substitution, we assigned it to the FeIV=O stretching mode. This band is considered to arise from the ferryl intermediate, but its appearance was much earlier than the corresponding intermediate of bovine cytochrome c oxidase (> 100 microseconds). The 361 cm-1 band showed the 16O/18O isotopic frequency shift of 14 cm-1 similar to the case of bovine cytochrome c oxidase reaction.

Cytochrome b Group↗

PubMed1994

Protection against cisplatin-induced nephrotoxicity in the rat by inducers and an inhibitor of glutathione S-transferase.

In an attempt to decrease cisplatin-induced nephrotoxicity, glutathione S-transferase (GST) inducers and a GST inhibitor were combined with cisplatin and administered to rats. t-Stilbene oxide (t-SO) and propylthiouracil (PTU) were the GST inducers, and ketoprofen was the GST inhibitor. Combinations of these GST inducers and the inhibitor with cisplatin decreased cisplatin-induced nephrotoxicity. The drug combinations with cisplatin inhibited the cisplatin-induced increase in urinary total GST activity. The combination of t-SO with cisplatin increased total GST activity in the kidney, compared to levels in the cisplatin only group. The t-SO combination recovered the cisplatin alone-induced decrease in GST-alpha activity to control levels. However, glutathione peroxidase (GSHpx) activity after the t-SO combination was ever further reduced compared to the cisplatin alone-induced decrease. The combination of PTU, with cisplatin increased total GST, GST-alpha and GSHpx activity, compared to the cisplatin alone group. However, PTU severely decreased the glutathione (GSH) level. The combination of ketoprofen with cisplatin normalized GST-mu and -alpha activity, and elevated the cisplatin-induced decrease of GSHpx activity and GSH. These findings suggest that ketoprofen decreases cisplatin-induced nephrotoxicity.

Animals↗

PubMed1994

[CT evaluation of extravascular perfusion of contrast medium and its potential to a new method of diagnosis: an experimental study using macro, micro-molecular contrast media].

To evaluate the dynamics of extravascular perfusion, dynamic CT with two different molecular sized contrast media was performed on VX2 tumor of rabbit. The first dynamic CT was performed with a bolus injection of iopamidol (IP:120 mgI/ml, 5 ml). After ascertaining that the tumor attenuation had returned to the pre-contrast level, the second dynamic CT was performed on the same slice with bolus injection of iodoethylated starch (IES:120 mgI/ml). The time-density (T-D) curves of the same tumor area on the images obtained by two contrast media were compared. The T-D curve with IP showed definitely higher level than that with IES. This occurrence can be explained that IP, 13 A in size, has higher permeability distributing not only in the intravascular space, but also into the extravascular space. On the other hand, IES, 200 A in size, will stay mostly in the intravascular space. From this, we consider that the attenuation difference between the two curves will be an indicator for the dynamics of extravascular perfusion, suggesting to become a new method for CT diagnosis.

Animals↗

PubMed1994

[Experimental study on vascular permeability and hemodynamics of nonionic dimeric contrast media (Iotrolan): a comparison to nonionic monomer on dynamic CT and angiography].

The difference of vascular permeability and hemodynamics between Iotrolan and Iopamidol was experimentally studied on dynamic CT and angiography. A hemodialyzer with 60 A pores were applied as a phantom of a target organ with capillaries and extravascular space. Dynamic CT scans and DSA of the phantom were performed with injection of each contrast medium and time-density curves obtained from several regions of interest were compared. The dynamic CT scans performed at 40 seconds after the completion of injection, showed that Iopamidol was mostly distributed at the site of inlet, while Iotrolan was mostly at the center of the phantom. Time-density curves on DSA with Iotrolan revealed lower and shorter peak density and time than did Iopamidol. In conclusion, Iotrolan has lower permeability than that of Iopamidol because of its larger molecular size. Iotrolan has slower flow through catheters and capillaries than that of Iopamidol because of its higher viscosity. One should be aware the difference between the two contrast media and be careful to the analysis of time-density curves of dynamic CT and DSA.

Angiography, Digital Subtraction↗