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Biomedical subjects

K Moriyama

Publications and source records attributed to K Moriyama.

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

Wide distribution of laminin-5 gamma 2 chain in basement membranes of various human tissues.

Laminin 5 (LN5), a heterotrimer of laminin alpha 3. beta 3. and gamma 2 chains. is a laminin isoform which strongly promotes adhesion. migration. and scattering of cells through binding to integrins alpha 3 beta 1, alpha 6 beta 1 and alpha 6 beta 4. To get an insight into the physiological functions of LN5, we prepared a mouse monoclonal antibody to human laminin gamma 2 chain and used it for immunohistochemical analysis of laminin gamma 2 chain in normal human tissues. The basement membranes of various epithelial tissues, such as the skin, lung, small intestine, stomach, kidney and prostate, were immunostained with the anti-laminin gamma 2 chain monoclonal antibody. In addition, the basement membrane of the surface germinal epithelium in the ovary was also positive for laminin gamma 2 chain. These results suggest general roles of LN5 in the anchorage of various types of epithelial cells to the underlying basement membrane and in the expression of their cellular functions. Moreover, deposition of laminin gamma 2 chain around small arteries and veins was observed in the thymus and spleen. This lymphatic organ-specific expression of vascular LN5 might provide a novel function of LN5 in immune responses.

Adult↗
PubMed1998

A novel homozygous missense mutation in the apo A-I gene with apo A-I deficiency.

We analyzed the genetic defect in a 67-year-old Japanese male patient with apolipoprotein (apo) A-I and high density lipoprotein (HDL) deficiencies, corneal opacities, and coronary artery disease. The plasma concentrations of apoA-I and HDL cholesterol were 2.9 to 7.3 mg/dL and 0.08 to 0.19 mmol/L, respectively. The lecithin:cholesterol acyltransferase (LCAT) activity and cholesterol esterification rate were <40% of normal control values. LCAT mass was 550% of normal control. Sequence analysis of polymerase chain reaction-amplified DNA of the proband's apoA-I gene showed a homozygous T-to-A transition resulting in the substitution of Val 156 with Glu (apoA-I Oita). Direct sequencing of samples obtained from other family members showed that the brother was homozygous, whereas the son was a heterozygous carrier of apoA-I Oita. The heterozygote for apo A-I Oita showed nearly 60% of normal apoA-I and normal HDL cholesterol levels. In vivo turnover studies in rabbits demonstrated that the variant apoA-I was rapidly cleared from plasma compared with normal human apoA-I. Our data suggest that the Val156Glu substitution is associated with apoA-I and HDL deficiency, partial LCAT deficiency, and corneal opacities and that Val156 of apoA-I may play an important role in apoA-I function.

Aged↗
PubMed1998

Induction of ectopic corticotropic tumor in mouse embryos by exo utero cell transplantation and its effects on the fetal adrenal gland.

To establish an in vivo experimental system for developmental endocrinology research, AtT-20 cells, a corticotropic tumor cell line, were transplanted by exo utero manipulation into mouse embryos on embryonic day 14. The induced tumor secreted ACTH in situ, and the circulating ACTH level was elevated. This was the first model for studying the regulation of ACTH in the mouse fetal adrenal in vivo and the first continuous ACTH treatment model in rodent fetuses. The changes in the adrenal gland from the tumor-induced embryos were analyzed by light microscopic morphometry, immunohistochemistry for steroidogenic enzymes, and electron microscopy. In the treated adrenal, the volume of the inner cortical zone was significantly larger than that in controls. In the inner zone, cell density was decreased, and average cell size was increased, whereas bromodeoxyuridine-incorporation was not increased. The enlarged inner zone cells expressed an enhanced level of cytochrome P45011beta, the corticosterone-synthesizing enzyme, and the serum corticosterone level was increased. Electron microscopy showed an active form of the organelles involved in steroidogenesis. These findings indicate that ACTH stimulates both adrenocortical hypertrophy and steroidogenesis in fetal mice. Potential perspectives of the novel paradigm in this research for molecular developmental endocrine study are discussed.

Adrenal Glands↗
PubMed1998

Combination of interleukin-6 and soluble interleukin-6 receptors induces differentiation and activation of JAK-STAT and MAP kinase pathways in MG-63 human osteoblastic cells.

Studies on the role of interleukin-6 (IL-6) in bone metabolism have been accumulating. However, its effects on osteoblasts are still unclear because the results are conflicting depending on the study models employed. We reasoned that these conflicting data are due to variable expression levels of membrane-bound IL-6 receptors (IL-6Rs). In the present study, we found that IL-6 in combination with soluble IL-6R (sIL-6R) consistently caused a marked elevation of alkaline phosphatase and a decrease in proliferation in the human osteoblastic cell line MG-63, which expressed no detectable membrane-bound IL-6R and failed to respond to IL-6. These effects of IL-6/sIL-6R were blocked by neutralizing antibodies to the IL-6 signal transducer gp130, suggesting an involvement of IL-6 signaling in the elicitation of the effects of IL-6/sIL-6R. Upon stimulation with IL-6/sIL-6R, the gp130, cytoplasmic Janus kinases JAK1 and JAK2 were tyrosine phosphorylated. Moreover, signal transducers and activators of transcription STAT1 and STAT3 were also tyrosine phosphorylated, translocated to the nucleus, and bound to the putative STAT-binding DNA elements. In addition, mitogen-activated protein (MAP) kinase was also activated in response to IL-6/sIL-6R These data demonstrate that sIL-6R may enhance the responsiveness of MG-63 cells to IL-6. Thus, IL-6 in collaboration with sIL-6R may modulate differentiation and proliferation of osteoblastic cells, presumably by activating two distinct signaling pathways of JAK-STAT and MAP kinase.

Alkaline Phosphatase↗
PubMed1998

Comparison of craniofacial and dentoalveolar morphologies of three Japanese monozygotic twin pairs with cleft lip and/or palate discordancy.

OBJECTIVE: In this study, we analyzed the craniofacial and dentoalveolar morphologies of three pairs of monozygotic twins discordant for cleft lip and/or palate (CL/P) in order to evaluate the effects of environmental factors on growth and development. DESIGN: Craniofacial and dentoalveolar morphologies revealed by analyses of cephalograms and dental casts were compared for each pair of twins discordant for CL/P. SUBJECTS: In case 1, the subjects were 10-year-old male twins, one of whom had a repaired unilateral cleft lip and alveolus and one of whom had an unrepaired unilateral cleft lip. In case 2, the subjects were 13-year-old female twins, one of whom had a repaired bilateral cleft lip and palate and one of whom had an unrepaired unilateral cleft lip. In case 3, the subjects were 9-year-old female twins, one of whom had a repaired unilateral cleft lip and palate and one of whom had no cleft. RESULTS: Cephalometric analysis disclosed distinguished intrapair differences in the maxillary and mandibular morphologies in cases 2 and 3. However, the tooth axes of the incisors in operated subjects were consistently influenced in all three cases. Dental cast analysis indicated that the shapes and sizes of the alveolar and dental arches in the operated subjects were affected in case 2 and, more severely, in case 3, while they looked fairly similar in case 1. CONCLUSIONS: Cephalometric and dental cast analyses demonstrated characteristic intrapair differences between the twins discordant for CL/P according to each cleft type. These morphological differences indicate that surgical closure of clefts may have considerable effects on craniofacial and dentoalveolar growth and development in CL/P patients.

Adolescent↗
PubMed1998

Evidence for apoptosis signal-regulating kinase 1 in the regenerating palatal epithelium upon acute injury.

Apoptosis signal-regulating kinase 1 (ASK1), a recently identified mitogen-activated protein (MAP) kinase kinase kinase, is a key element in the mechanism of stress- and cytokine-induced apoptosis. However, pathophysiologic roles of ASK1 in vivo are poorly understood. In the present study, we analyzed the ASK1 expression in injured rat palate using an immunohistochemical approach to investigate the roles of ASK1 during the process of wound healing. In the normal rat palatal epithelium, a weak cytoplasmic staining of ASK1 was observed in keratinocytes of the prickle cell layer. After mucoperiosteal injury of the palate, ASK1 was clearly observed in the suprabasal keratinocytes surrounding the wound. ASK1 expression was most evident at Day 2 after injury in the edge of the migrating epithelium. Thereafter, the intensity of ASK1 staining decreased gradually until the re-epithelialization was completed at Day 10 to 14. A staining with the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end-labeling method identified a number of apoptotic keratinocytes in the suprabasal layers at the healing edge. Active induction of epithelial apoptosis was readily detectable from Day 5 after injury. In double-staining analysis, the temporal and spatial pattern of ASK1 expression correlated well with the appearance of apoptotic keratinocytes. p38 MAP kinase, a downstream component of ASK1, was found to be activated at the sites of ASK1 expression, suggesting that increased expression of ASK1 leads to activation of downstream MAP kinase signaling pathway in vivo. These results suggest a significant contribution of ASK1 to the epithelial apoptosis in the process of mucoepithelial wound repair.

Animals↗
PubMed1997

Multistep control of pituitary organogenesis.

Lhx3 and Lhx4 (Gsh4), two closely related LIM homeobox genes, determine formation of the pituitary gland in mice. Rathke's pouch is formed in two steps-first as a rudiment and later as a definitive pouch. Lhx3 and Lhx4 have redundant control over formation of the definitive pouch. Lhx3 controls a subsequent step of pituitary fate commitment. Thereafter, Lhx3 and Lhx4 together regulate proliferation and differentiation of pituitary-specific cell lineages. Thus, Lhx3 and Lhx4 dictate pituitary organ identity by controlling developmental decisions at multiple stages of organogenesis.

Animals↗
PubMed1997

Basic fibroblast growth factor induces apoptosis in myofibroblastic cells isolated from rat palatal mucosa.

The effect of basic fibroblast growth factor (bFGF) on apoptosis in normal rat palatal fibroblasts and rat palatal scar fibroblasts was examined by the TUNEL method in order to clarify the mechanism of apoptosis induction in myofibroblasts during the scar formation process. A percentage of scar fibroblasts undergoing apoptosis was significantly higher than that of palatal fibroblasts when they were treated with bFGF succeeding to serum starvation. Palatal fibroblasts, phenotypically modulated into myofibroblasts by the pretreatment with transforming growth factor-beta 1 (TGF-beta 1), similarly showed a higher level of apoptosis induction by bFGF-treatment. TGF-beta 1 elevated protein and mRNA level of FGF receptor (FGFR) in palatal fibroblasts. Tyrosine autophosphorylation of FGFR upon stimulation by bFGF was significantly higher in scar fibroblasts than in normal palatal fibroblasts. These findings suggested that bFGF may be a potential stimulator of apoptosis in myofibroblasts during palatal scar formation and that FGFR may be responsible for this process.

Animals↗
PubMed1997

Lhx4, a LIM homeobox gene.

LIM homeobox genes are well conserved in evolution and play important roles as transcriptional regulators of embryonic development. Here we report on the structure of LIM domains of the mouse Lhx4 (Gsh4) gene. The cDNA was generated by modified reverse transcription-PCR from midgestation embryo templates, using a degenerate consensus primer. The deduced amino acid sequence of the first LIM domain reveals 77% identity and that of the second domain reveals 86% identity with the corresponding sequences of the closely related Lhx3 gene. In addition, there is 38-56% similarity to other members of the Lhx gene family. The LIM consensus sequence is well conserved in Lhx4.

Amino Acid Sequence↗
PubMed1997

The mechanism of mutation induction by a hydrogen bond ambivalent, bicyclic N4-oxy-2'-deoxycytidine in Escherichia coli.

The triphosphate of the nucleoside deoxyribosyl dihydropyrimido[4,5-c][1,2]oxazin-7-one (dP) is known to be incorporated into DNA efficiently by Taq polymerase and is a useful tool for polymerase-mediated in vitro mutagenesis. It is shown here that dP is a potent mutagen in Escherichia coli and Salmonella typhimurium . In E.coli , this deoxycytidine analog induces both GC-->AT and AT-->GC transitions. No induced transversions are observed. It is highly mutagenic in wild-type E.coli, but this is much reduced in a strain lacking thymidine kinase. Mutagenesis induced by dP is efficiently inhibited by the addition of thymidine. Partially purified thymidine kinase from E.coli catalyzes phosphorylation of dP to its 5'-monophosphate. When E.coli was grown in the presence of dP, the nucleoside analog was incorporated into its DNA. The content of dP in DNA was dependent on the concentration of dP added to the medium. The incorporation characteristics of the 5'-triphosphate of dP (dPTP) were also studied using E.coli DNA polymerase I large fragment. The results confirm that this triphosphate can be incorporated opposite A and G in the template with similar efficiencies. This indicates that dP is metabolized as a thymidine analog and that the resulting triphosphate induces a high rate of mutagenesis through replicational errors.

Base Sequence↗
PubMed1997

Transforming growth factor-beta 1 modulates myofibroblastic phenotype of rat palatal fibroblasts in vitro.

The effects of transforming growth factor-beta 1 (TGF-beta 1) on normal rat palatal fibroblasts in vitro were investigated in the present study in order to unravel the precise mechanisms by which the phenotypic modulation of fibroblasts occurs during the scar formation process. TGF-beta 1 dramatically changed the morphology of normal palatal fibroblasts from polygonal into an elongated shape, which was very similar to that of fibroblasts derived from experimental immature scar tissue in rat palatal mucosa. This morphological transition was concomitant with an increase in the expression of alpha-smooth muscle (alpha-SM) actin protein, a marker for myofibroblasts, when determined by immunocytochemistry. An immunoblot study also revealed that alpha-SM actin expression in palatal fibroblasts became evident after 24 h of TGF-beta 1 treatment and increased time-dependently up to 72 h. Northern blot analysis showed that TGF-beta 1 stimulated endogenous TGF-beta 1 mRNA expression in palatal fibroblasts within 24 h. Neither epidermal growth factor nor basic fibroblast growth factor had any effect on either alpha-SM actin expression or TGF-beta 1 mRNA expression. Pretreatment of palatal fibroblasts with TGF-beta 1 significantly increased the contractile capacity in a three-dimensional collagen gel culture, even when the culture medium was deprived of TGF-beta 1 for 72 h of the experimental period. Moreover, the contractility of scar fibroblasts, which highly expressed alpha-SM actin protein and TGF-beta 1 mRNA, was significantly lowered by a neutralizing antibody to TGF-beta 1. These data strongly suggest that TGF-beta 1 is a potential inducer of phenotypic expression of myofibroblasts in palatal fibroblasts and that auto-induction of TGF-beta 1 mRNA expression may play an important role in the scar formation process in palatal mucosa.

Actins↗
PubMed1997

Effects of amiloride on the neurally mediated contraction of rat mesenteric artery.

The effects of amiloride on contraction evoked by perivascular nerve stimulation were studied in a ring preparation of rat mesenteric artery. The contraction evoked by nerve stimulation was abolished by tetrodotoxin or prazosin. Amiloride depressed the nerve-induced contraction concentration dependently. Noradrenaline induced a tonic contraction in the artery. Amiloride inhibited the noradrenaline-induced contraction concentration dependently. The excitatory junctional potential (e.j.p.) recorded intracellularly was abolished by tetrodotoxin. The amplitude of the e.j.p. was not altered by prazosin or amiloride. These results indicate that amiloride inhibits the perivascular nerve-mediated contraction of mesenteric artery mainly through postsynaptic adrenoceptor inhibition and not through mechanisms related to e.j.p.

Adrenergic Fibers↗
PubMed1997

Enhanced core protein production by hepatitis B virus bearing a mutation in the precore region.

An HBV DNA tandem dimer bearing GTG instead of the precore initiation codon (p2WPC-), that bearing an amber mutation at precore codon 28 (p2WPCTer) and that of a wild-type were introduced into HepG2 cells. p2WPC- produced no HBeAg, the same amount of HBsAg as the wild-type, and 2-4 times as much HBcAg and progeny virus DNA. p2WPCTer produced no HBeAg, the same amount of HBsAg, 2 times as much HBcAg and a slightly increased amount of progeny virus. The amounts of p21c peptide in both mutants determined by immunoblotting correlated well with the ELISA titers. These results suggest that these precore single point mutations are responsible for the enhanced core peptide production.

Blotting, Southern↗
PubMed1997

Hepatitis GB virus C genome in the serum of aplastic anaemia patients receiving frequent blood transfusions.

GB virus C (GBV-C) RNA was detected in five of 18 patients with aplastic anaemia who had received blood transfusions, whereas it was not detected in eight patients who had not received any transfusions. Antibody against hepatitis C virus (anti-HCV) was detected in nine patients in the transfusion group, compared with one of eight who had not received any transfusions. Therefore, the route of transmission of both GBV-C and HCV in these patients appeared to have been multiple blood transfusion. Since all of the GBV-C RNA-positive patients harboured anti-HCV, GBV-C seems to frequently superinfect with HCV. Neither GBV-C nor HCV is likely to have been a causative agent of the anaemia in the cases examined.

Adolescent↗
PubMed1997

Inhibition of tumor promoter activity toward mouse fibroblasts and their in vitro transformation by tissue inhibitor of metalloproteinases-1 (TIMP-1).

Tissue inhibitor of metalloproteinases-1 (TIMP-1), a natural inhibitor of matrix metalloproteinases (MMPs), is known to inhibit invasion and metastasis of tumor cells. In the present study we examined anti-tumor promoter activity of TIMP-1 and its effect on in vitro cell transformation using BALB/3T3 cells in low serum culture medium. In the dye transfer assay the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) continuously blocked gap-junctional intercellular communication (GJIC) of BALB/3T3 cells in confluent phase. TIMP-1 did not prevent transient inhibition of GJIC induced by TPA, but it quickly restored the reduced GJIC level to the control level. The recovery of GJIC was dependent on the concentration of TIMP-1 from 1 to 1000 ng/ml. In an in vitro two-stage transformation assay in which BALB/3T3 cells were treated with 0.5 microg/ml N-metyl-N'-nitro-N-nitrosoguanidine as initiator and 100 ng/ml TPA as promoter, TIMP-1 at concentrations > 10 ng/ml inhibited the focus formation of transformed cells by approximately 60%. TIMP-2 and a synthetic MMP inhibitor showed a similar inhibitory activity on in vitro cell transformation. Furthermore, zymographyic analysis showed that TPA treatment of BALB/3T3 cells induced secretion of gelatinase B and stromelysin-1 into the culture medium. These results indicate that TIMP-1 and TIMP-2 have inhibitory activity on in vitro transformation of cells. It seems likely that TPA-inducible MMPs are involved in carcinogenesis and TIMPs have a protective role against carcinogenesis in vivo.

3T3 Cells↗
PubMed1997

Reduced antigen production by hepatitis B virus harbouring nucleotide deletions in the overlapping X gene and precore-core promoter.

Hepatitis B virus (HBV) genomes with deletions in the precore-core (preC-C) promoter have been detected in HBV infections without serological markers. To address whether the mutations are responsible for the reduced production of virus antigenes, either an 8 bp (8d, position 1763 to 1770) or a 20 bp (20d, 1753 to 1772) deletion was created in a wild-type (wt) HBV clone. Both mutations cause premature termination of the overlapping X ORF. When introduced into HepG2 cells, both mutants produced reduced amounts of HBsAg, HBcAg and HBeAg, but released the same or more virion-associated DNA compared with the wt. A co-transfection of the 20d mutant with a small amount of intact X gene resulted in a 3-fold increase of HBcAg production compared to transfection with either the 20d or wt alone. When the promoter region was cloned into CAT plasmids, the 8d preC promoter showed weak activity and its initiation site was shifted 6 to 10 bp downstream. The preC promoter activity of 20d was not detectable by CAT ELISA and 5' RACE. The levels of C transcripts of both mutants were higher than that of the wt, and their start sites were not altered. Therefore, the deletions cause the reduction of HBsAg, HBcAg and HBeAg although the mutant viruses can still replicate in cultured cells. The reduction of HBeAg is due to both the reduced preC promoter activity and the defect in HBx. The reduction of HBcAg is due to the disrupted X gene, despite augmented C promoter activity.

Amino Acid Sequence↗
PubMed1997

Degenerative hairlets on the vestibular sensory cells in mutant bustling (BUS/Idr) mice.

The bustling mouse (BUS/Idr: bus) is a mutant mouse strain which exhibits deafness, bustling/hyperkinetic behaviour and functional disorders seemingly related to the vestibular system. This phenotype develops in homozygous (bus/bus) mice and has been shown from cross experiments to be genetically induced by a single autosomal recessive gene. We previously detected, with light and electron microscopy, post-natal degeneration of the inner ear sensory cells in homozygotes. In the present study, we examined, by electron microscopy, the development of pathological changes in the sensory epithelia of the macula acustica and crista ampullaris of homozygous mice of various ages, paying special attention to the detailed morphology of the sensory hairlets. The homozygous mice exhibited specific pathological changes: a decrease in the number of hairs; disarrangement of the kinocilium-stereocilia pattern; and, fused and/or very large stereocilia. Homozygotes also frequently exhibited apical cytoplasmic herniation, or bleb of hair cells, as well as a degenerated kinocilium in the sensory epithelium. Heterozygotes showed similar changes, but to a lesser degree and frequency. As for the vestibular organs, similar pathological changes had developed at day, 17 of gestation. These pathological findings and onset suggest that the BUS mouse may be a mutant mouse strain distinct from other reported strains which display similar behaviour, and may be a useful animal model for the study of human degenerative vestibular disorders.

Animals↗