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Biomedical subjects

T Ishibashi

Publications and source records attributed to T Ishibashi.

At least 19 recordsLinked to original sources
PubMed2001

Growth-inhibitory effect of a streptococcal antitumor glycoprotein on human epidermoid carcinoma A431 cells: involvement of dephosphorylation of epidermal growth factor receptor.

An antitumor glycoprotein [streptococcal acidic glycoprotein (SAGP)] purified from an extract of Streptococcus pyogenes inhibited the growth of human epidermoid carcinoma A431 cells overexpressing epidermal growth factor receptor (EGFR) in a time- and a concentration-dependent manner. The antiproliferative effect of SAGP was diminished by preincubating the cells with pertussis toxin and by coadministration of sodium orthovanadate, an inhibitor of protein tyrosine phosphatases (PTPases). Western blot analysis showed that the immunoreactivity of a M(r) 170,000 band of cell lysate to antiphosphotyrosine antibody was reduced by SAGP, and the effect was abolished by sodium orthovanadate. The phosphotyrosine level of the precipitant with anti-EGFR antibody was reduced by SAGP, which was abolished by preincubation with pertussis toxin or by a coadministration with sodium orthovanadate. The PTPase activity transiently increased in the lysate of cells incubated with SAGP and was inhibitable by sodium orthovanadate. Additionally, preincubation of serum-starved A431 cells with SAGP decreased the epidermal growth factor-induced tyrosine phosphorylation of EGFR, and the effect of SAGP was sodium orthovanadate sensitive. These findings indicate that dephosphorylation of the M(r) 170,000 EGFR by activation of PTPase(s) may be responsible in part for the antiproliferative effect of SAGP on A431 cells.

Antibiotics, Antineoplastic↗
PubMed2001

Two types of replication protein A 70 kDa subunit in rice, Oryza sativa: molecular cloning, characterization, and cellular & tissue distribution.

Replication protein A (RPA), which is comprised of three subunits, is an important factor involved in DNA replication, repair, and transcription. We isolated and characterized 70 and 32 kDa subunits of RPA from rice (Oryza sativa cv. Nipponbare) termed OsRPA70a and OsRPA32. OsRPA70a shows a low level of homology with OsRPA1 which was isolated from deepwater rice (Oryza sativa cv. Pin Gaew 56), previously. We also succeeded to isolate OsRPA70b which is homologue to OsRPA1 from Oryza sativa cv. Nipponbare. OsRPA70a shows only 33.8% sequence identity with OsRPA70b, indicating that two different types of 70 kDa RPA subunits are present in Oryza sativa cv. Nipponbare. These subunits showed differences in their expression patterns among tissues. The transcripts of OsRPA70a and OsRPA32 were expressed strongly in proliferating tissues such as root tips and young leaves that contain root apical meristem and marginal meristem, respectively, and weakly in the mature leaves which have no proliferating tissues. On the other hand, OsRPA70b was expressed mostly in the proliferating tissues. The roles of these molecules in plant DNA replication and DNA repair are discussed.

Amino Acid Sequence↗
PubMed2001

Expression of NeuroD and TrkB in developing and aged mouse olfactory epithelium.

To better understand the roles of NeuroD, a member of the basic helix-loop-helix transcription factor family, during the differentiation of olfactory receptor neurons, we studied the expression of NeuroD in developing and aging mouse olfactory epithelium (OE). During embryonic period, NeuroD expression is confined in the basal compartment of OE. During neonatal period, NeuroD expression is detected in the middle compartment and in the basal compartment of OE. In the adult, the number of NeuroD expressing cells in the basal compartment significantly decreased, while the NeuroD-positive cells in the middle compartment was maintained throughout lifetime. This dual phase expression pattern of NeuroD suggests multiple roles of NeuroD in the neurogenesis of ORNs.

Aging↗
PubMed2001

Identification of dual specificity phosphatases induced by olfactory bulbectomy in rat olfactory neuroepithelium.

Dual specificity protein tyrosine phosphatases (dsPTPs) are a subfamily of protein tyrosine phosphatases implicated in the regulation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK), and p38 mitogen-activated protein kinases (MAPKs) which are target enzymes activated by a wide range of cell-surface stimuli. Like these kinases, a class of dsPTP has been implicated in cell differentiation, regeneration, and apoptosis. In order to isolate dsPTPs which might play an important role in neuronal regeneration and apoptosis in olfactory neuroepithelium, we subcloned DNA fragments amplified by reverse transcription-polymerase chain reaction (RT-PCR), using degenerate oligonucleotide primers based on the conserved amino acid regions within the catalytic domain of dsPTPs, from rat olfactory epithelial RNA 1 and 4 h after an olfactory bulbectomy. The PCR products were subcloned into the pCRII vector, and 23 clones were chosen for further characterization. The sequence of these 23 individual clones revealed that two clones were identical to the rat dsPTP, MKP-3, and the other 21 clones were identical to the rat dsPTP, MKP-1. By Northern analysis, the MKP-1 transcript was induced and peaked 4 h following a bulbectomy. Similar results were obtained with the MKP-3 transcript. These results suggest that MKP-1 and MKP-3 may be involved in the early steps of apoptosis in vivo in rat olfactory neuroepithelium.

Animals↗
PubMed2001

Response of experimental retinal neovascularization to thiazolidinediones.

OBJECTIVE: To determine the effect of thiazolidinediones (TZDs) on experimental retinal neovascularization. METHODS: The ability of the TZDs troglitazone and rosiglitazone maleate (1-20 micromol/L) to inhibit retinal endothelial cell (REC) proliferation, migration, tube formation, and signaling was determined in response to vascular endothelial growth factor (VEGF). In vivo studies were performed using the oxygen-induced ischemia model of retinal neovascularization. Neonatal mice were treated with intravitreous injection of 0.5 microL of troglitazone (100 micromol/L) or rosiglitazone maleate (100 micromol/L), or vehicle, and retinal neovascularization was assayed qualitatively and quantitatively by means of angiography and histological examination. RESULTS: Expression of the TZD receptor, peroxisome proliferator-activated receptor gamma, was confirmed in RECs by means of Western immunoblotting. Rosiglitazone and troglitazone inhibited VEGF-induced migration (P< .05), proliferation (P< .05), and tube formation (P< .01) by RECs in vitro beginning at 10 micromol/L. Rosiglitazone and troglitazone inhibited phosphorylation of extracellular signal-regulated mitogen-activated protein kinase 1 in RECs. Intravitreous injection of rosiglitazone or troglitazone inhibited development of retinal neovascularization (P< .01) but did not significantly inhibit VEGF overexpression in the ganglion cell layer of the ischemic retina. CONCLUSION: The TZDs inhibit experimental retinal neovascularization with an effect that is primarily downstream of VEGF expression. CLINICAL RELEVANCE: The TZDs are widely prescribed and should be evaluated for their potential to inhibit the progression of diabetic retinopathy.

Animals↗
PubMed2001

Differential expression of major gap junction proteins, connexins 26 and 32, in rat mammary glands during pregnancy and lactation.

We examined the expression pattern of two major gap junction proteins, connexin 26 (Cx26) and connexin 32 (Cx32), in rat mammary glands during pregnancy and lactation. Immunohistochemically the two different Cxs were coexpressed in acinar cells and were independently modulated according to the physiological cell activity. Western blot analysis demonstrated that Cx26 gradually increased from early pregnancy, while Cx32 rapidly and dramatically increased at 16 h after parturition, and that both Cxs reached a maximum early in lactation. Increased expression of both Cxs was confirmed by Northern blot analysis showing that their mRNA transcripts were significantly induced on the day of parturition. We also analyzed double-immunofluorescent staining for Cx26 and Cx32 on a confocal laser scanning microscope, in order to examine colocalization of these Cxs in situ. Cx26 immunoreactivity mostly overlapped with Cx32-positive sites in acinar cells of lactating mammary glands, indicating that both Cxs were colocalized together in the same gap junctional plaques in lactation. These results suggest that upregulation of Cx26 and Cx32 in acinar cells at lactating stages, with colocalization in the same gap junctional plaques, may be important for control of secretion by acinar cells in rat mammary glands.

Animals↗
PubMed2001

Relocalization of apoptosis-inducing factor in photoreceptor apoptosis induced by retinal detachment in vivo.

Apoptosis-inducing factor (AIF) is a novel mediator in apoptosis. AIF is a flavoprotein that is normally confined to the mitochondrial intermembrane space, yet translocates to the nucleus in several in vitro models of apoptosis. To investigate the role of AIF in the apoptotic process in vivo, we induced retinal detachment (RD) by subretinal injection of sodium hyaluronate, either in Brown Norway rats or in C3H mice. Apoptotic DNA fragmentation, as determined by terminal nick-end labeling, was most prominent 3 days after RD. The subcellular localization of AIF was examined by immunohistochemistry and immunoelectron microscopy. In normal photoreceptor cells, AIF was present in the mitochondrion-rich inner segment. However, AIF was found in the nucleus after RD. Photoreceptor apoptosis developed similarly in C3H control mice, and in mice bearing the gld or lpr mutations, indicating that cell death occurs independently from the CD95/CD95 ligand system. Both the mitochondrio-nuclear transition of AIF localization and the nuclear DNA fragmentation were inhibited by subretinal application of brain-derived neurotrophic factor. To our knowledge, this is the first description of AIF relocalization occurring in a clinically relevant, in vivo model of apoptosis.

Animals↗
PubMed2001

Expression of very low density lipoprotein receptor mRNA in circulating human monocytes: its up-regulation by hypoxia.

Although very low density lipoprotein (VLDL) receptor expression by macrophages has been shown in the vascular wall, it is not clear whether or not circulating monocytes express the VLDL receptor. We investigated the expression of VLDL receptor mRNA in human peripheral blood monocytes and monocyte-derived macrophages by reverse transcriptase polymerase chain reaction (RT-PCR) and nucleotide sequencing after subcloning of PCR product. VLDL receptor mRNA was detected both in peripheral blood monocytes and monocyte-derived macrophages. Expression of VLDL receptor mRNA was upregulated by hypoxia in monocytes, whereas treatment with oxidized LDL, interleukin-1beta or monocyte chemoattractant protein-1 did not affect the levels of VLDL receptor mRNA in monocytes and macrophages. The present study shows a novel response of VLDL receptor mRNA to hypoxia, suggesting a role for VLDL receptor in the metabolism of lipoproteins in the vascular wall and the development of atherosclerosis.

Adult↗
PubMed2001

Soy intake related to menopausal symptoms, serum lipids, and bone mineral density in postmenopausal Japanese women.

OBJECTIVE: To evaluate the effects of dietary isoflavones in soy products on menopausal symptoms, lipid profiles, and bone mineral densities in postmenopausal Japanese women. METHODS: We estimated the daily intakes of isoflavones in the diets of 478 postmenopausal Japanese women who reported soy consumption. We recorded serum values of fasting total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and apolipoproteins. Bone mineral density was measured at the lumbar spine (L2-L4) by dual energy x-ray absorptiometry. Women were assigned to two groups according to years since menopause (early and late postmenopausal groups), and each group was subcategorized into four groups according to dietary isoflavone intake. Relationships between isoflavone intake, menopausal symptoms, lipid profiles, and bone mineral density were examined in each group. RESULTS: The mean estimated intake of isoflavones among 478 women was 54.3 mg/day. With stepwise regression analysis we found that weight and years since menopause were significant independent predictors of bone mineral density. Bone mineral densities adjusted to years since menopause and weight were significantly different in the highest intake compared with lowest intake category (P <.001) within the early and late postmenopausal groups. In the early postmenopausal group, significant differences were found in palpitation and backaches between the high and low intake categories but were not significant in the late postmenopausal group. CONCLUSION: High consumption of soy products is associated with increased bone mass in postmenopausal women and might be useful for preventing hypoestrogenic effects.

Adult↗
PubMed2001

Saccular renal artery aneurysm treated with an autologous vein-covered stent.

A 32-year-old woman underwent an autologous saphenous vein-covered stent deployment for the treatment of a saccular aneurysm on the distal renal artery. Complete exclusion of the aneurysm was immediately obtained. One year after the treatment, remarkable shrinkage of the aneurysm was demonstrated by means of computed tomography, and wide patency of the renal artery and the stent was shown by means of angiography.

Adult↗
PubMed2001

Embryo growth and amino acid concentration profiles of broiler breeder eggs, embryos, and chicks after in ovo administration of amino acids.

Two experiments were conducted to evaluate the effect of in ovo amino acid (AA) injections in broiler breeder eggs on AA utilization of embryos. All AA used in these experiments were pure crystalline AA in free-base form. Treatments in Experiment 1 comprised 1) control eggs (no injection), 2) 0.5 mL sterile-distilled water injected eggs, and 3) eggs injected with an AA solution suspended in 0.5 mL sterile-distilled water. Injections were administered into the yolk at Day 7 of incubation. At hatch, chicks were killed and bled, and plasma AA concentration was determined. Plasma AA concentration of hatched chicks decreased (P < 0.05) when water was injected. In addition, all AA from eggs injected with AA, except Glu and Lys, were decreased (P < 0.05) at hatch as compared to control eggs. However, AA pattern was not affected by in ovo water injection, but the AA ratio to Lys was reduced by in ovo AA injection. Experiment 2 was conducted to evaluate whole internal egg AA concentrations over incubation time in the presence or absence of in ovo AA administration. Treatments in Experiment 2 comprised 1) control eggs (no injection), and 2) eggs injected with a AA solution at Day 7 of incubation. The AA contents of embryo, yolk, albumen, and allantoic and amnion fluids were analyzed over time during incubation (Days 0, 7, 14, and 19 of incubation). On Day 14 of incubation, there were no differences in AA contents of all tissues between the control group and the group injected with AA on Day 7 of incubation. On Day 19 of incubation, AA contents of embryo, yolk, albumen, and allantoic and amnion fluids were increased (P < 0.05) as mediated by in ovo administration of AA at Day 7 of incubation. These results suggest that in ovo administration of AA may increase AA concentrations in chicken embryos and other egg contents.

Amino Acids↗
PubMed2001

Effects of blockade of the renin-angiotensin system on tissue factor and plasminogen activator inhibitor-1 synthesis in human cultured monocytes.

OBJECTIVES: To clarify the pathophysiological significance of the renin-angiotensin system (RAS) in monocytes, we examined the effect of its blockade on tissue factor and plasminogen activator inhibitor-1 (PAI-1) synthesis in human cultured monocytes. METHODS: Monocytes were isolated from healthy volunteers and cultured. Tissue factor and PAI-1 antigens in culture medium and cells were measured by enzyme-linked immunosorbent assay and Western blotting, and mRNA levels were assessed by reverse-transcriptase polymerase chain reaction. RESULTS: We show that the RAS is present in isolated human peripheral blood monocytes. Exogenous angiotensin II increased the levels of tissue factor antigen and mRNA in cultured monocytes, but not of PAI-1 synthesis. An angiotensin converting enzyme (ACE) inhibitor (captopril) and an angiotensin II type 1 (AT1) receptor antagonist (candesartan) decreased the levels of tissue factor protein and mRNA in cultured monocytes. These alterations were accompanied by a reduction in the levels of tumour necrosis factor-alpha protein and mRNA. The levels of PAI-1 protein were reduced by captopril, but not by candesartan. A bradykinin B2 receptor antagonist abolished the suppressive effect of captopril on PAI-1 antigen. CONCLUSIONS: An ACE inhibitor and an AT1 receptor antagonist reduced tissue factor synthesis in these cells. We show different actions of these agents on PAI-1 synthesis. ACE inhibition decreased PAI-1 synthesis mediated by bradykinin production, but AT1 receptor inhibition had no effect.

Angiotensin II↗
PubMed2001

Prevalence of age related maculopathy in a representative Japanese population: the Hisayama study.

AIM: To determine the prevalence of age related maculopathy (ARM) in a representative older Japanese population. METHODS: 1486 residents of Hisayama town, Fukuoka, Japan, aged 50 years or older were examined and the presence of ARM was determined by grading from fundus examination by indirect ophthalmoscope, slit lamp, and colour fundus photographs. RESULTS: The prevalence rate of drusen, which occurred with comparable frequency in men and women, was 9.6%. The frequency of drusen increased with age (p <0.01). Hyperpigmentation and/or hypopigmentation of the retina was present in 3.2%, geographic atrophy in 0.2%, and neovascular age related macular degeneration in 0.67%. The frequency of neovascular age related macular degeneration was significantly higher in the men (1.2% v. 0.34%, p <0.01). CONCLUSIONS: Early and late stage ARM is less common among Japanese people than among white people in Western countries, while late stage ARM is more common among Japanese than among black people.

Age Factors↗
PubMed2001

Ten-year survivor with multiple myeloma in first complete remission following treatment with conventional chemotherapy. Case report and a review of the literature.

A 62-year-old woman with multiple myeloma, who has been in complete remission (CR) for 10 years, is reported. The patient was treated with conventional chemotherapy, including nitrosourea derivatives. Five patients with myeloma, including the present case, who have survived for 10 years or more in CR and on whom detailed clinical descriptions were published, are reviewed. Their disease condition represented "a cure" or "a state extremely close to cure". The review indicates the following favorable prognostic factors common to these patients: age < or =65 years and a rapid response to treatment. Progressive bone destruction and/or lytic changes at disease onset is perhaps not a bad prognostic factor in myeloma patients with excellent outcome.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Efficacy of ipriflavone in preventing adverse effects of leuprolide.

The purpose of this study was to evaluate the efficacy of ipriflavone in preventing bone loss, decreasing in serum cholesterol and decreasing the rate of appearance of vasomotor symptoms, as well as the effects of ipriflavone on reduction of myoma volume by estrogen deficiency during treatment with the GnRH analog leuprolide. One hundred two women (mean age, 44.3 +/- 0.53 yr) receiving leuprolide therapy for uterine leiomyoma were randomly allocated to two groups (group A, leuprolide only; group B, leuprolide with ipriflavone). Bone mineral density of the lumbar spine was measured by dual-energy x-ray absorptiometry before and after treatment for 6 months. Levels of serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C) were measured before treatment and after 3 and 6 months of treatment. Subjects were asked to report the appearance of vasomotor symptoms throughout treatment. Myoma node volumes were measured before treatment and after treatment for 6 months. Bone mineral density was reduced in both groups, with reduction rates of -5.26% in group A and -3.70% in group B (P < 0.01 vs. group A). Changes in bone markers were not significant in either group. TC was significantly increased in both groups, and TG levels were increased significantly after 3 and 6 months of treatment in group A but not in group B. There was no significant difference between these two groups in amount of increase of either TC or TG. LDL-C levels were increased significantly after 3 and 6 months of treatment in both groups, and the differences between the groups (11.7% in group A vs. 7.5% in group B at 3 month and 22.6% in group A vs. 8.4% in group B at 6 month) were significant. Severe vasomotor symptoms were reduced in group B. The rates of reduction of myoma volume were 49.8% in group A and 52.9% in group B; this difference between groups was not significant. Ipriflavone efficaciously alleviated the adverse effects of estrogen deficiency such as bone loss and increase in LDL-C level, and the ability of leuprolide therapy to reduce myoma volume was not decreased by ipriflavone administration.

Adult↗
PubMed2001

Large thrombus in the ascending aorta successfully treated by thrombolysis--an unusual cause of acute massive myocardial infarction.

A 52-year-old woman suffered from acute massive myocardial infarction in association with a large thrombus in the ascending aorta. She was a moderate smoker and was taking hormone supplement therapy for menopausal hormone insufficiency and the contraceptive pill for endometriosis. Cardiac angiography revealed a large mobile filling defect close to the orifice of the left coronary artery, but the left coronary artery could not be visualized. Her hemodynamic condition was impaired so greatly that intraarterial counterpulsation and intravenous thrombolysis was immediately performed. The thrombus dissolved in 1 h and recanalization of the left coronary artery was achieved without serious systemic thromboembolism. She has been doing well with no cardiac events for 7 years. This is the second report of a large thrombus in ascending aorta being the cause of acute myocardial infarction in the whole territory of the left coronary artery, and the first to diagnose such a thrombus antemortem and treat it successfully.

Aorta↗
PubMed2001

Regulation of endothelial nitric oxide synthase and endothelin-1 expression by fluvastatin in human vascular endothelial cells.

We investigated the effects of fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, on endothelial vasoactive substances using human umbilical vein endothelial cells (HUVECs). Incubation of HUVECs with fluvastatin for 12 h increased endothelial nitric oxide synthase (eNOS) mRNA expression in a concentration-dependent manner (peak, 276 +/- 38%, mean +/- S.D., of the control, at 1.0 microM fluvastatin, P<0.01). In addition, fluvastatin increased eNOS protein production (245 +/- 51% of the control level, P<0.05) as well as nitrite production (165 +/- 35% of the control level, P<0.01). In contrast, incubation of HUVECs with 1.0 microM fluvastatin for 12 h significantly reduced the production of endothelin-1 (ET-1) and preproET-1 mRNA expression in HUVECs (28 +/- 1% and 39 +/- 1% of the control level, respectively, P<0.01). Our results suggest that fluvastatin might be involved in improvement of endothelial function and prevention of the progression of atherosclerosis.

Base Sequence↗