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Biomedical subjects

K Maruyama

Publications and source records attributed to K Maruyama.

At least 55 records · Page 3Linked to original sources
PubMed2001

p21Cip-1/SDI-1/WAF-1 gene is involved in chondrogenic differentiation of ATDC5 cells in vitro.

Development of skeletal cartilage is characterized with coupling growth arrest and cell differentiation. Here, to understand the cyclin-dependent kinase inhibitors involved in the progression of chondrogenic differentiation, we examined changes in the expression levels of cyclin-dependent kinase inhibitor members using mouse ATDC5 prechondrocytes as a widely used in vitro model of cartilage differentiation. Up-regulation of p21 and p27 mRNA was observed following a decrease in growth rate of prechondrocytes, and both transcripts subsequently accumulated during chondrogenic differentiation; p15, p18, and p19 mRNA, in contrast, did not change during differentiation. Only the up-regulation of p21 mRNA during differentiation was prevented by the continuous treatment of early chondrogenic inhibitor, parathyroid hormone, indicating a close correlation between differentiation and p21 induction in ATDC5 cells. Therefore, to examine the role of p21 during chondrogenesis, we established stable cell lines overexpressing full-length p21 antisense RNA in ATDC5. The reduction of endogenous p21 in these cell lines caused inhibition of early chondrogenic differentiation in ATDC5, indicating that p21 gene plays an important role in this process of the cells in vitro. Furthermore, the level of p21 protein and p21.CDK2 complexes transiently increased during differentiation, but not in undifferentiated cells, leading to a decrease in CDK2-associated kinase. However, differentiation-dependent expressed p21 protein was degraded by a proteasome-dependent pathway. Thus, the progression of chondrogenic differentiation requires down-regulation of CDK2-associated kinase with an increase in p21 protein and subsequent degradation of this protein by a proteasomal pathway.

Animals↗
PubMed2001

Subcellular compartment and molecular subdomain of beta-amyloid precursor protein relevant to the Abeta 42-promoting effects of Alzheimer mutant presenilin 2.

Increased production of amyloid beta peptides ending at position 42 (Abeta42) is one of the pathogenic phenotypes caused by mutant forms of presenilins (PS) linked to familial Alzheimer's disease. To identify the subcellular compartment(s) in which familial Alzheimer's disease mutant PS2 (mt PS2) affects the gamma-cleavage of betaAPP to increase Abeta42, we co-expressed the C-terminal 99-amino acid fragment of betaAPP (C100) tagged with sorting signals to the endoplasmic reticulum (C100/ER) or to the trans-Golgi network (C100/TGN) together with mt PS2 in N2a cells. C100/TGN co-transfected with mt PS2 increased levels or ratios of intracellular as well as secreted Abeta42 at similar levels to those with C100 without signals (C100/WT), whereas C100/ER yielded a negligible level of Abeta, which was not affected by co-transfection of mt PS2. To identify the molecular subdomain of betaAPP required for the effects of mt PS2, we next co-expressed C100 variously truncated at the C-terminal cytoplasmic domain together with mt PS2. All types of C-terminally truncated C100 variants including that lacking the entire cytoplasmic domain yielded the secreted form of Abeta at levels comparable with those from C100/WT, and co-transfection of mt PS2 increased the secretion of Abeta42. These results suggest that (i) late intracellular compartments including TGN are the major sites in which Abeta42 is produced and up-regulated by mt PS2 and that (ii) the anterior half of C100 lacking the entire cytoplasmic domain is sufficient for the overproduction of Abeta42 caused by mt PS2.

Alzheimer Disease↗
PubMed2001

Neprilysin degrades both amyloid beta peptides 1-40 and 1-42 most rapidly and efficiently among thiorphan- and phosphoramidon-sensitive endopeptidases.

To identify the amyloid beta peptide (Abeta) 1-42-degrading enzyme whose activity is inhibited by thiorphan and phosphoramidon in vivo, we searched for neprilysin (NEP) homologues and cloned neprilysin-like peptidase (NEPLP) alpha, NEPLP beta, and NEPLP gamma cDNAs. We expressed NEP, phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PEX), NEPLPs, and damage-induced neuronal endopeptidase (DINE) in 293 cells as 95- to 125-kDa proteins and found that the enzymatic activities of PEX, NEPLP alpha, and NEPLP beta, as well as those of NEP and DINE, were sensitive to thiorphan and phosphoramidon. Among the peptidases tested, NEP degraded both synthetic and cell-secreted Abeta1-40 and Abeta1-42 most rapidly and efficiently. PEX degraded cold Abeta1-40 and NEPLP alpha degraded both cold Abeta1-40 and Abeta1-42, although the rates and the extents of the digestion were slower and less efficient than those exhibited by NEP. These data suggest that, among the endopeptidases whose activities are sensitive to thiorphan and phosphoramidon, NEP is the most potent Abeta-degrading enzyme in vivo. Therefore, manipulating the activity of NEP would be a useful approach in regulating Abeta levels in the brain.

Amino Acid Sequence↗
PubMed2001

Angiotensin AT(1) and AT(2) receptors differentially regulate angiopoietin-2 and vascular endothelial growth factor expression and angiogenesis by modulating heparin binding-epidermal growth factor (EGF)-mediated EGF receptor transactivation.

Angiotensin II (Ang II)-mediated signals are transmitted via heparin binding epidermal growth factor (EGF)-like growth factor (HB-EGF) release followed by transactivation of EGF receptor (EGFR). Although Ang II and HB-EGF induce angiogenesis, their link to the angiopoietin (Ang)-Tie2 system remains undefined. We tested the effects of Ang II on Ang1, Ang2, or Tie2 expression in cardiac microvascular endothelial cells expressing the Ang II receptors AT(1) and AT(2). Ang II significantly induced Ang2 mRNA accumulations without affecting Ang1 or Tie2 expression, which was inhibited by protein kinase C inhibitors and by intracellular Ca(2+) chelating agents. Ang II transactivated EGFR via AT(1), and inhibition of EGFR abolished the induction of Ang2. Ang II caused processing of pro-HB-EGF in a metalloproteinase-dependent manner to stimulate maturation and release of HB-EGF. Neutralizing anti-HB-EGF antibody blocked EGFR phosphorylation by Ang II. Ang II also upregulated vascular endothelial growth factor (VEGF) expression in an HB-EGF/EGFR-dependent manner. AT(2) inhibited AT(1)-mediated Ang2 expression and phosphorylation of EGFR. In an in vivo corneal assay, AT(1) induced angiogenesis in an HB-EGF-dependent manner and enhanced the angiogenic activity of VEGF. Although neither Ang2 nor Ang1 alone induced angiogenesis, soluble Tie2-Fc that binds to angiopoietins attenuated AT(1)-mediated angiogenesis. These findings suggested that (1) Ang II induces Ang2 and VEGF expression without affecting Ang1 or Tie2 and (2) AT(1) stimulates processing of pro-HB-EGF by metalloproteinases, and the released HB-EGF transactivates EGFR to induce angiogenesis via the combined effect of Ang2 and VEGF, whereas AT(2) attenuates them by blocking EGFR phosphorylation. Thus, Ang II is involved in the VEGF-Ang-Tie2 system via HB-EGF-mediated EGFR transactivation, and this link should be considerable in pathological conditions in which collateral blood flow is required.

Angiopoietin-1↗
PubMed2001

Detection of hepatic oxidative DNA damage in patients with hepatoblastoma and children with non-neoplastic disease.

BACKGROUND: The authors have revealed a significant association between hepatoblastoma and low birth weight. This study was done to explore the evidence that liver cells were oxidatively damaged, based on the hypothesis that oxidative damage to DNA is involved in the development of hepatoblastoma in children of low birth weight. PROCEDURE: Oxidative DNA damage in the liver was examined by immunohistochemically detecting the presence of a DNA repair product, 8-hydroxy-2'-deoxyguanosine (8-OHdG), in five patients with hepatoblastoma and 14 children with non-neoplastic disease. RESULTS: Positive staining for 8-OHdG was observed in all five patients with hepatoblastoma. Distribution of 8-OHdG positivity was diffuse in the intralobular area in one patient and was restricted to the periportal area of the lobules in four patients. There was no apparent correlation between birth weight of the patients, histological findings in the liver, and the distribution of 8-OHdG positivity. In children with non-neoplastic disease, 8-OHdG was detected in nine of 14 patients, and 8-OHdG was positive in the intralobular area of the liver parenchyma except in one patient. CONCLUSIONS: These results suggest that the cause of oxidative DNA damage in patients with hepatoblastoma may be different from the cause, extensive parenchymal damage to the liver, in children with non-neoplastic disease, but the 8-OHdG formation is not specific to hepatoblastoma patients of low birth weight. Further studies to elucidate the true reason for the high incidence of hepatoblastoma in children of low birth weight are necessary.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Three-dimensional morphological analysis of antigen-antibody reaction in hepatic sinusoids preserved in hypothermic UW solution.

ICAM-1 antigen-antibody reaction was visualized by three-dimensional immunoscanning electron microscopy of hepatic sinusoids in rat liver treated with hypothermic University of Wisconsin (UW) organ preservation solution. The results were compared with similar antigen-antibody reactions carried out with immunoliposomes injected in vivo. Morphologically, the hepatic sinusoids were preserved well during the hypothermic procedure. Endothelial cells had a large number of fenestrations, which partly aggregated and formed sieve plates. ICAM-1 expression was induced by injection of LPS and detected by monoclonal antibody in the UW solution followed by gold-labeled secondary antibody. ICAM-1 was restricted mostly to the unique areas of sieve plates with immature, small fenestrations. A similar distribution of ICAM-1 was present when detected by in vivo injection of immunoliposomes containing the monoclonal ICAM-1 antibody. The results showed that antigen-antibody reactions can take place in livers preserved in hypothermic UW solution. Further, the reaction is similar to that which could occur in vivo during transplantation. This suggests that it may be possible to block potentially harmful antigen-antibody reactions by addition of appropriate antibodies to hypothermic UW solution prior to transplantation.

Adenosine↗
PubMed2001

Clinical value of lung uptake of iodine-123 metaiodobenzylguanidine (MIBG), a myocardial sympathetic nerve imaging agent, in patients with chronic heart failure.

This study investigated the clinical value of I-123 MIBG pulmonary accumulation and washout in patients with chronic heart failure (CHF). Nineteen patients with CHF and 15 normal volunteers (NL) were included. The uptake ratio of heart to mediastinum (H/M), that of lung fields to mediastinum (L/M), and washout rate (WR) of the heart and lung fields were calculated in anterior planar images and compared with results of echocardiography and cardiac catheterization. In the CHF group, the lung uptake in delayed images increased and lung WR was decreased, suggesting pulmonary endothelial lesions. Furthermore, there was a negative correlation between right and left lung WR and pulmonary arterial diastolic pressure (PA(D)) and pulmonary arterial systolic pressure (PA(s)) in the CHF group. Since the WR of MIBG reflected PA, it may be used as an index of severity of cardiac dysfunction.

3-Iodobenzylguanidine↗
PubMed2001

Polymorphisms of renin-angiotensin system genes in childhood IgA nephropathy.

We investigated whether polymorphisms of the renin-angiotensin system genes are involved in IgA nephropathy in Japanese children. We identified the M235T polymorphism of the angiotensinogen (AGT) gene, the I/D polymorphisms of the angiotensin-converting enzyme (ACE) gene, and the A1166C polymorphism of the angiotensin II type 1 receptor gene in 95 Japanese children with IgA nephropathy and 99 healthy Japanese adults. There were no differences in the genotype and allele frequencies of these genes between patients with IgA nephropathy and controls. Urinary protein excretion at the time of biopsy was significantly greater in patients with the TT genotype of the AGT gene than in those with the MM/MT genotypes of the AGT gene (1.32 +/- 1.42 versus 0.75 +/- 0.78 g/day; P = 0.01) and in patients with the ID/DD genotypes of the ACE gene than in those with the II genotype of the ACE gene (1.45 +/- 1.50 versus 0.63 +/- 0.56 g/day; P = 0.001). Thus, the TT genotype of the AGT gene and the ID/DD genotype of the ACE gene are associated with increased severity of proteinuria, suggesting that AGT and ACE gene polymorphisms may play a significant role in the progression of IgA nephropathy in Japanese children.

Adolescent↗
PubMed2001

Dynamic change of cells expressing MMP-2 mRNA and MT1-MMP mRNA in the recovery from liver fibrosis in the rat.

BACKGROUND/AIMS: The aim of this study was to investigate whether both matrix metalloproteinase-2 (MMP-2) and membrane type 1 MMP (MT1-MMP) participate in the spontaneous resolution of liver fibrosis. METHODS: Transcription of both genes was examined by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH). Gelatinase activity was investigated by zymography. RESULTS: Gene expression by RT-PCR showed that both genes increased in the process of liver fibrosis, then decreased gradually in the recovery phase. ISH revealed that distribution of positive cells changed quickly in the recovery phase. Positive cells were widely seen in the liver, mainly around fibrous septa, in the aggressive phase, but were exclusively observed at the interface between the resolving fibrous band and the parenchyma, then were diffusely located in the lobules in the recovery phase. Main cells expressing both mRNAs seemed to be stellate cells for their morphology, though they did not express characteristic cell markers. Some hepatocytes and Kupffer cells expressed both mRNAs in the recovery phase. Gelatinase activity of MMP-2 increased in the recovery phase of 8-week-treated rat liver by gelatin zymography. CONCLUSIONS: The results of present study suggest that both enzymes participate in the destruction of extracellular matrix in coordination with MMP-13.

Animals↗
PubMed2001

Physical condition of preterm infants with periventricular leukomalacia.

The aim of this study is to determine the general condition of preterm infants with severe brain lesions and to compare it with that of normal preterm infants. The Score for Neonatal Acute Physiology (SNAP) was calculated in nine preterm infants with periventricular leukomalacia (PVL) whose initial electroencephalograms showed grade IV depression (PVL group), 18 preterm infants who did not require mechanical ventilation during the neonatal period, Spontaneous respiration (SR group), and 18 preterm infants who required mechanical ventilation (MV group). The sum of the following four items in SNAP was separately calculated and called the 'lung score': PaO(2), PaO(2)/FiO(2) ratio, PaCO(2), and oxygenation index. In addition to SNAP, we evaluated some neonatal variables. SNAP is lower in the SR group than in the PVL (P<0.05) or MV (P<0.01) groups. The lung score was also lower in the SR group than in the PVL (P<0.05) or MV (P<0.01) groups. On the other hand, the residual score (SNAP minus lung score) was not significantly different among the three groups. The physical condition of infants with PVL was not poor, although respiratory distress was often observed.

Apgar Score↗
PubMed2001

Expression of heparanase in oral cancer cell lines and oral cancer tissues.

In the process of metastasis, cancer cells secrete several enzymes which degrade extracellular matrices (ECMs) and basement membranes (BMs) of blood vessels. One of them, heparanase, has been reported to be an important enzyme when metastatic cancer cells invade blood vessels. The enzyme cleaves heparan sulfate (HS), a main component of ECM and BM. In the present study, HS-degrading ability of several human oral cancer cell lines (HSC2, HSC3, HSC4, Ca9-22, NA, ACC3 and Ab-J) and tissues derived from human oral squamous cell carcinomas (both metastatic and non-metastatic) were investigated by measuring heparanase activities and levels of heparanase mRNA by a quantitative reverse transcriptase-polymerase chain reaction. The catalytic activities and the mRNA levels of heparanase showed a good agreement. Clinical demonstration of cancer metastasis generally correlated with high levels of heparanase activity and its mRNA. The results suggest that heparanase activity and its mRNA level are good diagnostic parameters for evaluating the metastatic properties of human oral cancer cells.

Adolescent↗
PubMed2001

Liposomes bearing polyethyleneglycol-coupled transferrin with intracellular targeting property to the solid tumors in vivo.

PURPOSE: The purpose of this study was to determine the usefulness of transferrin (TF)-pendant-type polyethyleneglycol (PEG)-liposomes (TF-PEG-liposomes), in which TF was covalently linked to the distal terminal of PEG chains on the external surface of PEG-liposomes as a carrier for in vivo cytoplasmic targeting to tumor cells. METHODS: Small unilamellar TF-PEG-liposomes (100-140 nm in diameter) were prepared from DSPC, CH, DSPE-PEG, and DSPE-PEG-COOH (2:1:0.11:0.021, molar ratio), and were conjugated to TF via the carboxyl residue of DSPE-PEG-COOH. The intracellular targeting ability of TF-PEG-liposomes to tumor cells was examined in vitro and in Colon 26 tumor-bearing mice. RESULTS: TF-PEG-liposomes, bearing approximately 25 TF molecules per liposome, readily bound to mouse Colon 26 cells in vitro and were internalized by receptor-mediated endocytosis. TF-PEG-liposomes showed a prolonged residence time in the circulation and low RES uptake in Colon 26 tumor-bearing mice, resulting in enhanced extravasation of the liposomes into the solid tumor tissue. Electron microscopic studies in Colon 26 tumor-bearing mice revealed that the extravasated TF-PEG-liposomes were internalized into tumor cells by receptor-mediated endocytosis. CONCLUSION: TF-PEG-liposomes had the capabilities of specific receptor binding and receptor-mediated endocytosis to target cells after extravasation into solid tumors in vivo. Such liposomes should be useful for in vivo cytoplasmic targeting of chemotherapeutic agents or plasmid DNAs to target cells.

Animals↗
PubMed2001

An optimized fast protocol for magnetic resonance imaging of the temporomandibular joint.

OBJECTIVES: To provide a fast protocol for MR imaging of the TMJ with high contrast resolution of both soft tissue and joint fluid. METHODS: A fast turbo-spin echo (TSE) pulse sequence was developed. The new technique was compared with T1W conventional spin echo (CSE) and T2W TSE sequences in imaging 57 TMJs in 50 patients. Disc location and contour and bone delineation were assessed on three images of each TMJ by one observer. Presence and location of intra-articular fluid were evaluated on both standard T2W and new TSE images. Image quality was scored on a 3 point-scale by one observer. RESULTS: The net image acquisition time for one plane was 2 min with the new TSE sequence compared with approximately 5-10 min for T1W and 4 min for T2W. The new sequence provided equivalent diagnostic information to a combination of T1W CSE for disc position and contour and bone contour and T2W TSE sequence for joint fluid. CONCLUSIONS: The examination time for MRI of the TMJ can be considerably reduced with the new fast TSE pulse sequence without compromising image quality.

Adolescent↗
PubMed2001

Cloning of porcine IGF1 receptor cDNA and detection of sequence polymorphisms using RT-PCR.

A cDNA encoding the porcine type 1 insulin-like growth factor receptor (IGF1R) was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR). The sequence of a 4.2-kb product was determined and had an open reading frame, encoding 1367 amino acids with 98.1 and 95.2% sequence similarity to the human and rat IGF1R, respectively. In the comparison of RT-PCR derived IGF1R sequences from 12 unrelated pigs, 12 silent sequence variants were found.

Animals↗
PubMed2001

Partial monosomy 10q with partial trisomy 11q due to paternal balanced translocation.

A male neonate with partial monosomy 10q and partial trisomy 11q, due to paternal balanced translocation, and who had cerebellar and olfactory lobe hypoplasia, cardiovascular defects, duodenal atresia and imperforate anus, is presented. To the best of our knowledge, this is the first report on this combination of chromosomal abnormalities.

Abnormalities, Multiple↗
PubMed2001

Two cases of bronchial asthma after treatment with amiodarone.

Amiodarone is a highly effective antiarrhythmic agent for the prevention of life-threatening arrhythmias. Two cases are described of patients who developed bronchial asthma after treatment with amiodarone. The bronchial asthma resolved after the dose of amiodarone was decreased in both patients. To our knowledge, an association between amiodarone and severe bronchial asthma has previously been reported only once in the medical literature. Physicians should note that amiodarone may cause bronchospasm in susceptible patients.

Aged↗