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Biomedical subjects

Y Arai

Publications and source records attributed to Y Arai.

At least 343 records · Page 19Linked to original sources
PubMed1997

Bone mass loss due to estrogen deficiency is compensated in transgenic mice overexpressing human osteoblast stimulating factor-1.

Osteoblast stimulating factor-1 (OSF-1) stimulates in vitro proliferation and differentiation of osteoblastic cells, and its gene is expressed in the bone and brain tissues in mammals and amphibians. To evaluate the in vivo function of OSF-1 in bone metabolism, transgenic mice overexpressing the human osf-1 gene driven by the osteocalcin promoter were generated. Femoral bone mineral content was increased in transgenic mice relative to wild-type controls as estimated by ash assay, depending on the transgene copy number per cell. In ovariectomized mice, bone mass loss due to estrogen deficiency was observed in both transgenic and control mice but bone mass was still higher in transgenic mice than in controls. Bone mass in ovariectomized transgenic mice was comparable to that in wild-type mice without ovariectomy. These observations indicate that OSF-1 may direct in vivo appositional bone formation by increasing osteoblast activity rather than decreasing osteoclast activity, suggesting a new way to treat osteoporosis with OSF-1.

Animals↗
PubMed1997

A negative regulatory region of the murine Hox11 gene.

The HOX11 gene was isolated from the chromosomal breakpoint of human T cell acute lymphoblastic leukemias with a chromosomal translocation t(10;14). Expression of this proto-oncogene is strictly controlled in normal tissues. However, regulatory elements of the gene have never been studied. Since the HOX11 gene is well conserved between human and murine, we sequenced 5' flanking region of the murine Hox11 gene and analyzed the elements. We identified the transcription start site (+1) of the gene using mRNA from fetal spleens by primer extension analysis. The start site was determined at 795 bp upstream from the ATG site. A typical TATA box sequence was found at 35 bp upstream from the start site. Furthermore, promoter activity of the 5' flanking region of the start site was monitored by luciferase assay. The activity mainly located within a 540-bp fragment immediately upstream from the start site (-540 to +1). The (-1240 to -540) region contained a negative regulatory element of the transcription. The TATA box sequence and the nucleotide sequence around the transcription start site were conserved in the human HOX11 gene. The transcription start site of the human HOX11 gene in normal tissues is discussed.

Animals↗
PubMed1997

The inv(11)(p15q22) chromosome translocation of de novo and therapy-related myeloid malignancies results in fusion of the nucleoporin gene, NUP98, with the putative RNA helicase gene, DDX10.

The inv(11)(p15q22) is a recurrent chromosomal abnormality associated with de novo and therapy-related myeloid malignancies. Here we report the molecular definition of this chromosomal aberration in four patients. Positional cloning showed the consistent rearrangement of the DDX10 gene on chromosome 11q22, which encodes a putative RNA helicase. The translocation targets the NUP98 gene on 11p15, a member of the FG peptide repeat nucleoporin family. In DDX10 and NUP98, the inv(11) breakpoints occurred within two introns of each gene and the two genes merged in-frame to produce the chimeric transcripts characteristic of this translocation. Although two reciprocal chimeric products, NUP98-DDX10 and DDX10-NUP98, were predicted, only NUP98-DDX10 appears to be implicated in tumorigenesis. DDX10 is predicted to be involved in ribosome assembly. NUP98 has been identified as a nuclear pore complex protein and a target of chromosomal translocation in acute myeloid leukemia through the t(7;11)(p15;p15) translocation. The predicted NUP98-DDX10 fusion protein may promote leukemogenesis through aberrant nucleoplasmic transport of mRNA or alterations in ribosome assembly.

Amino Acid Sequence↗
PubMed1997

Aberrant methylation of an imprinted gene U2af1-rs1(SP2) caused by its own transgene.

Genomic imprinting refers to the parental allele-specific expression of genes. The precise mechanism underlying this phenomenon, which may involve DNA methylation, is not yet known. U2af1-rs1(SP2) is an imprinted gene expressed from the paternal allele and is methylated on the maternal allele. Here we report an artificial system in which expression and methylation of the endogenous imprinted gene U2af1-rs1 can be affected by interaction with its own transgene in the testis. We suggest that there is a mechanism in male gametogenesis by which the U2af1-rs1 gene is kept unmethylated to be expressed in the offspring in addition to a mechanism in female gametogenesis by which the U2af1-rs1 gene is methylated and is not expressed in the offspring.

Alleles↗
PubMed1997

Renal effect of YM435, a new dopamine D1 receptor agonist, in anesthetized dogs.

The renal effects of YM435 ((-)-(S)-4-(3,4-dihydroxyphenyl)-7,8-dihydroxy -1,2,3,4-tetrahydroisoquinoline hydrochloride hydrate), a dopamine D1 receptor agonist, were investigated in anesthetized dogs. Intravenous infusion of YM435 (0.1-3 micrograms/kg per min) increased renal blood flow and decreased mean blood pressure in a dose-dependent manner with little effect on heart rate. Glomerular filtration rate, urine flow and urinary sodium excretion were concomitantly increased. The renal effect of YM435 by intravenous infusion at 0.3 microgram/kg per min was completely blocked by treatment with the selective dopamine D1 receptor antagonist SCH 23390 (7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazep ine hydrochloride). Furthermore, intravenous infusion of YM435 (0.3 microgram/kg per min) reversed the angiotensin II-induced decreases in renal blood flow, glomerular filtration rate, urine flow and urinary sodium excretion, and prevented the decrease in renal blood flow, glomerular filtration rate and urine flow induced by renal nerve stimulation and platelet-activating factor (PAF). These results suggest that intravenous administration of YM435 produces renal vasodilating and diuretic/natriuretic effects by stimulation of dopamine D1 receptors, and demonstrate that YM435 can inhibit angiotensin II-, renal nerve stimulation- and PAF-induced renal dysfunction.

Anesthesia↗
PubMed1997

c-erbB-2 oncoprotein: a potential biomarker of advanced prostate cancer.

BACKGROUND: Overexpression of the c-erbB-2 oncogene has been implicated in the development and/or prognosis of several human carcinomas, including that of the prostate. Recently, c-erbB-2 protein was found to be released in the circulation. The present study was undertaken to study the significance of serum c-erbB-2 protein determination in men with prostate cancer. METHODS: Serum c-erbB-2 protein determination was performed via immunoradiometric assay using two monoclonal antibodies that react with the extracellular domain of the protein. The study population consisted of 71 untreated prostate cancer patients. Of those, 33 with stage D2 disease entered a follow-up study. As control, serum c-erbB-2 protein levels were determined in 92 patients with benign prostatic hypertrophy. In addition, elevations of c-erbB-2 protein were examined in patients with various disease statuses: clinically well controlled (28 patients), disease progression (24 patients), and end-stage disease (17 patients). RESULTS: Elevation of serum c-erbB-2 protein level was observed in patients in advanced stages, such as stage D2 disease (30%), disease progression (42%), and end-stage disease (82.4%). In the follow-up study, patients with an elevated c-erbB-2 level had a significantly shorter interval to disease progression than did those with a normal level. CONCLUSIONS: The results suggest that c-erbB-2 can be used as a biomarker to identify a malignant subgroup in prostate cancer.

Biomarkers, Tumor↗
PubMed1997

Pure red cell aplasia with thymona: evidence of T-cell clonal disorder.

Pure red cell aplasia (PRCA) sometimes accompanies thymoma. Herein, we report a PRCA patient with thymoma with a clonal disorder of T cells. A 55-year-old man presented with anemia and anterior mediastinum tumor. The laboratory study revealed hemoglobin 8.2 g/dl; leukocytes 15.8 x 10(9)/L with 76.5% neutrophils, 20.0% lymphocytes, and reticulocytes 0.0%. Bone marrow aspirate smears and biopsy sections revealed normal myeloid and megakaryocyte differentiation and contained no erythroid precursors. We made the diagnosis of PRCA. The size of the lymphocytes was small without any granules in the cytoplasm. The surface marker of peripheral blood mononuclear cells demonstrated increased CD2+, CD3+, CD4-, and CD8+ populations. The mediastinal tumor was resected and a thymoma diagnosed. A monoclonal rearrangement of T-cell receptor (TCR)-beta-chain gene was found using Southern blot analysis of the mononuclear cells in both peripheral blood and thymoma. Treatment with prednisolone, thymectomy, and cyclophosphamide exerted no beneficial effect. After initiation of the Cyclosporin A therapy, the patient developed reticulocytosis. This PRCA case seems to present a neoplastic proliferation of CD8+ T cells in peripheral blood and thymus with a monoclonal rearrangement of the TCR-beta-chain gene.

Cell Differentiation↗
PubMed1997

Hydrostatic pressure influences mRNA expression of transforming growth factor-beta 1 and heat shock protein 70 in chondrocyte-like cell line.

The present study investigated the influence of hydrostatic pressure on the expression of cytokines and heat shock protein 70 in a chondrocyte-like cell line. Chondrocyte-like cells (HCS-2/8) were exposed to hydrostatic pressure by a special pressure apparatus. Total RNA for cytokines (interleukin-1 beta, basic fibroblast growth factor, insulin-like growth factor-I, and transforming growth factor-beta 1) and for heat shock protein 70 was extracted and was analyzed by a polymerase chain reaction method and Northern blotting. An assay for incorporation of [35S]sulfate was performed to assess proteoglycan synthesis. The expression of transforming growth factor-beta 1 mRNA was enhanced after exposure to 5-MPa of hydrostatic pressure and was reduced after 50 MPa, whereas the expression of heat shock protein 70 was enhanced following exposure to 50 MPa of hydrostatic pressure. The incorporation of [35S]sulfate into the cultured cells increased following exposure to 1-5 MPa of hydrostatic pressure and decreased following 10-50 MPa of pressure. These results suggest that hydrostatic pressure at physiologic levels enhances the expression of transforming growth factor-beta 1 mRNA in addition to increasing proteoglycan synthesis in chondrocytes and that excessively high hydrostatic pressure reduces the expression of transforming growth factor-beta 1 mRNA and increases the expression of heat shock protein 70 mRNA while decreasing proteoglycan synthesis.

Cartilage, Articular↗
PubMed1997

Intermittent hepatic arterial infusion of high-dose 5FU on a weekly schedule for liver metastases from colorectal cancer.

PURPOSE: We performed phase I and II studies to examine the usefulness of intermittent hepatic arterial infusion of high-dose 5-fluorouracid (5-FU) for patients with liver metastasis from colorectal cancer. METHODS: As the phase I study, 1000, 1250 and 1500 mg/m2 of 5-FU were administered over 5 h by hepatic arterial infusion on a weekly schedule to establish the recommended dose. Based on the results of the phase I study, the phase II study was performed to confirm the efficacy of the recommended dose thus obtained. RESULTS: In the phase I study, the dose-limiting factors of this therapy were gastrointestinal and central nervous system toxicities, and the recommended dose was judged to be 1000 mg/m2. In the phase II study, 1000 mg/m2 of 5-FU was administered over 5 h once a week on an outpatient basis, and this therapy was repeated as long as possible. The response rate was 78% (25/32), with an overall median survival time of 25.8 months (without extrahepatic lesions 25.9 months; with extrahepatic lesions 17.3 months). CONCLUSIONS: (1) Compared with conventional continuous infusion, the advantages of this therapy were that it caused no decrease in the patient's quality of life as a result of being permanently equipped with a pump and it thus enabled more cost-effective use of the pump, (2) The phase II study on 32 patients showed that this therapy caused no serious toxicities, with a response rate of 78% and a survival time of 25.8 months, which exceeded the results with conventional continuous infusion. If the reproducibility of these results is established in further studies involving multicenter collaboration, this therapy will be able to become the standard local chemotherapy for liver metastases from colorectal cancer. (3) Important problems remaining to be solved are improvement of the technical aspects and studies of combined use with systemic chemotherapy. Furthermore, to finally determine the position of this therapy in the treatment system for liver metastasis from colorectal cancer, it is necessary to conduct comparative trials versus systemic chemotherapy, using the survival time as the end-point.

Antimetabolites, Antineoplastic↗
PubMed1997

Developmental changes of glutamate receptors in the rat cerebral cortex and hippocampus.

We studied the immunohistochemical localization of the glutamate receptors (GluR-1, -2, and -3,) in the developing rat cerebral cortex and hippocampus using antibodies to GluR1 and to an epitope common to GluR2 and GluR3 (GluR2/3) subunits. In the cerebral cortex, GluR1 immunoreactivity appeared in the neurons from postnatal day (PND) 0, increased with maturation, was highest at PND 10, decreased until PND 30, and thereafter remained at the same level as on PND 0. GluR2/3 immunoreactivity appeared earlier in scattered neurons on embryonal day (ED) 18, increased with maturation and reached a peak between PND 10 and PND 15, after which the immunoreactivity gradually decreased and reached a plateau at PND 30. For both GluR1 and GluR2/3, some of the pyramidal neurons showed intense staining. In the pyramidal layers of the hippocampus, GluR1 and GluR2/3 immunoreactivity was found in all the pyramidal neurons of the CA1-4 area from ED 20. In the dentate gyrus of the hippocampus, GluR1 and GluR2/3 immunoreactivity was found in the neurons of the granule cells after PND 0. Immunoreactivity in the neurons of the subiculum was found after PND 5 and that of the polymorphic cell layers was found after PND 15-20. Our results indicate that the development of glutamate receptor subunits in the rat cerebral cortex and hippocampus is expressed in different spatial patterns and distinct temporal patterns throughout development and is scheduled during the early postnatal period, when synaptic plasticity or synaptic connection occurs in these regions.

Animals↗
PubMed1997

Prostate specific antigen adjusted for the transition zone volume as an indicator of prostate cancer.

PURPOSE: We compared prostate specific antigen (PSA) adjusted for the transition zone volume with PSA and PSA density with regard to value in diagnosing prostate cancer in men with intermediate PSA levels of 4.1 to 10.0 ng./ml. in a community based urology practice. MATERIALS AND METHODS: Between October 1994 and May 1996, PSA transition zone was obtained from 92 of 94 men who underwent systematic sextant biopsies and had a PSA value between 4.1 and 10.0 ng./ml. PSA transition zone, calculated by dividing the PSA value by the volume of the transition zone of the prostate, was compared with PSA and PSA density via the receiver operating characteristic (ROC) curves. RESULTS: Of the 92 men 12 (13.0%) had prostate cancer. ROC curve analysis demonstrated that PSA transition zone and PSA density predicted the biopsy outcome significantly better than PSA (p <0.05 and p <0.01, respectively). In a subset of 59 men with normal digital rectal examination PSA transition zone predicted the biopsy outcome better than PSA density, although without significant difference. With a cutoff value of 0.3 PSA transition zone had a sensitivity of 75% and a specificity of 54%. CONCLUSIONS: PSA transition zone is more specific than PSA in distinguishing benign from malignant disease in men with intermediate PSA levels of 4.1 to 10.0 ng./ml., especially in those with normal digital rectal examination. Further study is necessary to discuss whether PSA transition zone is superior to PSA density.

Aged↗
PubMed1997

Expression of the MDR1 and MDR3 gene products in acute and chronic leukemias.

We performed immunocytochemistry to detect mdr1 and mdr3 P-glycoproteins (P-gps) in 81 patients with acute and chronic leukemia, using the mdr1 P-gp-specific monoclonal antibody (MoAb) MRK16, and the mdr3 P-gp-specific MDR3M. Immunoreactivity for the mdr1 gene product was positive in 27 out of 81 (33%) patients. Immunoreactivity with the anti-mdr3 P-gp MoAb was positive in 20 out of 81 (25%) patients. Of 54 patients with acute leukemia, 17 (31%) were positive for mdr1 P-gp and 8 (15%) for mdr3 P-gp. A high proportion (60%) of patients with chronic lymphocytic leukemia (CLL) were mdr3 P-gp positive. Of the patients with granular-lymphocyte proliferative disorder (GLPD), a chronic T-cell or natural killer cell leukemia, 8/17 (47%) were positive for mdr1 P-gp and 6/17 (35%) for mdr3 P-gp. Of 23 patients with chronic leukemia (CLL and GLPD), 10 (37%) were positive for mdr1 P-gp and 12 (44%) for mdr3 P-gp. To clarify the function of the mdr3 P-gp, we examined the intracellular rhodamine123 (Rh123) levels of mdr1 P-gp-negative and mdr3 P-gp-positive leukemic cells from patients with acute lymphocytic leukaemia, on the addition of 10 microM cyclosporin A (CyA). The addition of CyA led to significant increases in intracellular Rh123 levels in mdr1 P-gp-negative and mdr3 P-gp-positive leukemic cells. Results of the assay for dye efflux suggested that the mdr3 P-gp has a role in drug resistance, and functional drug-efflux capacity. In 31 acute leukemia patients at initial diagnosis, mdr1 or mdr3 P-gp expression correlated significantly to an outcome of complete remission (CR). In 54 acute leukemia patients, exposure to precytotoxic agents correlated significantly to expression, with a significant higher number of patients mdr1 or mdr3 P-gp positive than negative. In the 54 patients with acute leukemia, mdr1 P-gp expression correlated to mdr3 P-gp expression significantly (p=0.0007). In the 27 patients with chronic leukemia (CLL and GLPD), mdr1 and mdr3 P-gp expression did not correlate to exposure to precytotoxic agents, nor did mdr1 P-gp expression correlate to mdr3 P-gp expression. It may be speculated that precytotoxic agents induced mdr1 and mdr3 P-gp expression in acute leukemia; however, in chronic leukemia, both P-gps were expressed independently of exposure to precytotoxic agents.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1997

Socioeconomic factors and dental caries in developing countries: a cross-national study.

The purpose of the present study was to analyze statistically correlations between socioeconomic factors and the prevalence of dental caries in developing countries. The DMFT index, which evaluates the incidence of dental caries, showed a positive correlation (P < 0.01) with several socioeconomic factors, such as life expectancy, adult literacy rate, school attendance rate, population employed in the service sector, population aged 15-64 years, and urban population. According to multiple regression analysis, population aged 15-64 years, population employed in the service sector, and urban population were the most influential independent socioeconomic variables, in descending order, with a regression coefficient of 0.635 and a coefficient of determination of 0.404 (P < 0.001). This finding suggests that the prevalence of dental caries in developing countries increases with the degree of urbanization.

Adolescent↗
PubMed1997

Antianginal effects of YM430, a novel calcium entry-blocking and beta-adrenoceptor-blocking agent in several experimental angina models.

1. We evaluated the antianginal effects of YM430 in several experimental models in vitro and in vivo. 2. In isolated dog coronary artery, YM430 (10(-8)-10(-6) M) inhibited 3,4-diaminopyridine-induced rhythmic contractions with an IC50 value of 59.2 nM. 3. In anesthetized rats, YM430 (10-100 mg/kg PO) inhibited arginine vasopressin-induced ST-segment depression with an IC50 value of 36.6 mg/kg PO. 4. In anesthetized dogs, YM430 (0.3 mg/kg IV) significantly inhibited ST-segment elevation induced by coronary artery occlusion. 5. These findings suggest that YM430 may be of value in the treatment of various types of angina pectoris such as variant and stable angina.

4-Aminopyridine↗
PubMed1997

Analysis of DNA ploidy using fresh frozen tissues of head and neck squamous cell carcinomas.

The DNA ploidy of fresh frozen tissues of head and neck squamous cell carcinomas was determined by flow cytometry to investigate whether DNA ploidy is correlated with various clinical and pathological parameters. The subjects were 51 patients who had been treated radically by our department. The DNA ploidy pattern was classified into three types, diploid, single aneuploid and multiploid, according to the DNA index and the DNA histogram. This is our original classification. No particular correlation could be detected between the DNA ploidy pattern and sex, age, primary tumour site or disease stage. The degree of tissue differentiation tended to be poorer in aneuploid tissues than in diploid tissues. The efficacy of chemotherapy was higher in aneuploid cases than in diploid cases. The recurrence rate was significantly lower in diploid cases than in multiploid cases. When disease stage, degree of histological differentiation, efficacy of the chemotherapy and the DNA ploidy pattern were subjected to multivariate analysis for correlation with the prognosis, the DNA ploidy pattern showed the highest correlation. The results suggest that the DNA ploidy as analyzed by flow cytometry can be used as an important prognostic factor.

Aged↗
PubMed1997

Early detection of axonal and neuronal lesions in prenatal-onset periventricular leukomalacia.

The expression of beta-amyloid precursor protein (beta-APP) immunoreactivity was investigated in 16 cases of prenatal-onset periventricular leukomalacia (PVL). beta-APP positive axons were found in the early stage of prenatal PVL, which included coagulation necrosis, microglial activation, axonal swelling or astrogliosis, but were not detectable in the late stage of prenatal PVL. Furthermore, beta-APP immunoreactive neurons were also observed in the fifth layer of pyramidal neurons of the cerebral cortex, corresponding to the beta-APP positive axons in PVL. Thus, beta-APP is detected as an early sign of axonal and neuronal lesions in prenatal-onset PVL, and neuronal beta-APP in the cerebral cortex may function to repair cell damage. In addition, prenatal PVL occurred at various stages before birth.

Amyloid beta-Protein Precursor↗