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Biomedical subjects

K Moriyama

Publications and source records attributed to K Moriyama.

At least 55 records · Page 3Linked to original sources
PubMed1999

Hyaluronic acid grafted with poly(ethylene glycol) as a novel peptide formulation.

Hyaluronic acids (HA) grafted with poly(ethylene glycol) (PEG) (PEG-g-HA) were synthesized. The materials characterization, enzymatic degradability and peptide (insulin) release from solutions of the copolymers were examined. Distribution of bioactive peptides within the polymer chain is well-known for combinations of PEG and polysaccharides as aqueous polymer two-phase systems. Insulin was preferentially partitioned into the PEG phase in a PEG/HA solution system. Enzymatic degradation of the copolymers was strongly dependent on the PEG content. Thermal analysis revealed that PEG-g-HA exhibited a variation in phase-separated structures depending on the PEG content. The solution of PEG-g-HA enabled insulin to remain in the PEG moieties dispersed in the HA matrix. Leakage of insulin from the copolymers was dependent upon the PEG content. Leakage rate of insulin from copolymer containing between 7 and 39% by weight of PEG were similar. A dramatic increase in leakage rate occurred when the PEG content was increased to greater than 39% by weight. It is considered that the loaded insulin was partitioned into the PEG moieties and became entangled with the PEG chains. The conformational change of insulin was effectively prevented in PEG-g-HA solutions, although insulin was denatured in storage of both phosphate buffered solution and HA solution. Such a heterogeneous-structured polymeric solution may be advantageous as an injectable therapeutic formulation for ophthalmic or arthritis treatment.

Biodegradation, Environmental↗
PubMed1999

Interferon-gamma inhibits the myofibroblastic phenotype of rat palatal fibroblasts induced by transforming growth factor-beta1 in vitro.

Interferon-gamma (IFN-gamma), a multifunctional cytokine, has been noted as a potential therapeutic agent for various fibrotic disorders, including excessive scar tissue formation. We previously reported that transforming growth factor-beta1 (TGF-beta1) induced the myofibroblastic phenotype in palatal fibroblasts derived from palatal mucosa, and that such effects might have a close link to palatal scar formation. In the present study, we examined the effects of IFN-gamma on TGF-beta1-pretreated palatal fibroblasts for the purpose of clarifying the suppressive potency against myofibroblastic phenotype expression in vitro. IFN-gamma significantly altered the spindle morphology of TGF-beta1-pretreated palatal fibroblasts into the polygonal one that was similar to the non-treated palatal fibroblasts. This change was parallel with a decrease in the expression of alpha-smooth muscle actin protein, a marker for myofibroblast, as determined by immunoblot analysis. Northern blot analysis showed that IFN-gamma inhibited proalpha2(I) collagen mRNA expression that was stimulated by TGF-beta1 pretreatment for 24 h. Furthermore, IFN-gamma decreased the cell contractility enhanced by TGF-beta1 pretreatment for 24 h in a three-dimensional collagen gel culture system. These results suggest that IFN-gamma may have negative effects with regard to controlling the myofibroblastic phenotype induced by TGF-beta1 in palatal fibroblasts.

Actins↗
PubMed1999

Matrilysin as a target for chemotherapy for colon cancer: use of antisense oligonucleotides as antimetastatic agents.

Matrilysin (MMP-7) is the smallest member of the matrix metalloproteinase (MMP) family. It is frequently expressed in various types of cancer including colon, stomach, prostate, and brain cancers. Previous studies have suggested that matrilysin plays important roles in the progression and metastasis of colon cancer. Recently, we have examined the effects of a matrilysin-specific antisense phosphorothioate oligodeoxyribonucleotide on in vitro invasion and liver metastasis in nude mice of two human colon carcinoma cell lines (CaR-1 and WiDr). In culture, the antisense oligonucleotide effectively inhibited both the secretion of matrilysin by CaR-1 cells and their in vitro invasion through a reconstituted basement membrane. In a nude mouse model, the antisense oligonucleotide potently suppressed the experimental liver metastasis of WiDr cells from the spleen. These results suggest that matrilysin has an important role in the liver metastasis of human colon cancer and that matrilysin antisense oligonucleotides have therapeutic potential for the prevention of metastasis.

Animals↗
PubMed1999

Schizophrenia: is it time to replace the term?

The attitudes of Japanese psychiatrists toward their patients who suffer from schizophrenia were investigated. We were concerned specifically with whether the psychiatrists inform their patients of the suspected diagnosis. We discuss how the term 'schizophrenia' may influence a psychiatrist's decision to inform his patients of the diagnosis. A self-reported questionnaire was distributed to 150 executive board members of the Japanese Society of Psychiatry and Neurology and analysis of the data obtained from 110 respondents was carried out. The results showed that the concepts that psychiatrists use when they give a diagnosis of schizophrenia vary considerably. Fifty-nine per cent of the respondents informed their patients of a diagnosis of schizophrenia on a case-by-case basis, while 37% informed only the patients' families. A tree analysis showed that the most important predictors for informing the patients of the diagnosis were assumptions about the public image of schizophrenia and a negative impression of the term schizophrenia, translated as 'Seishin Bunretsu Byou' in Japanese. The results revealed that the Japanese term for schizophrenia influences a psychiatrist's decision to inform patients of the diagnosis and that, by changing the term to a less stigmatized one, the disclosure of information about schizophrenia to patients would be promoted.

Attitude of Health Personnel↗
PubMed1999

A novel apolipoprotein E mutation, E2 (Arg25Cys), in lipoprotein glomerulopathy.

BACKGROUND: Lipoprotein glomerulopathy (LPG) is characterized by intraglomerular lipoprotein thrombosis and high plasma concentrations of apolipoprotein (apo) E. An apo E variant, apo E2 (Arg145Pro) Sendai, was recently identified in three patients with LPG. We detected a novel point mutation in the apo E gene in a patient with LPG, and we characterized the mutant apo E. METHODS: The propositus was a 32-year-old male patient on maintenance hemodialysis because of LPG. The mutation was detected by sequencing of genomic DNA from the patient and was confirmed by restriction fragment length polymorphism (RFLP) with Aor51HI. Recombinant apo E2 (Arg25Cys) Kyoto and normal apo E3 were expressed from COS-1 cells. Low-density lipoprotein (LDL) receptor-binding activities of the variants were determined in an in vitro competition assay. RESULTS: The propositus had the apo E phenotype E2/E4, as determined by isoelectric focusing, and the genotype epsilon3/epsilon4, as determined by RFLP with HhaI. Sequence analysis of amplified DNA showed a C to T transition, changing the codon for residue 25 from arginine to cysteine. The proband was a heterozygous carrier for apo E2 (Arg25Cys) Kyoto. A family study showed that the mother was a heterozygous carrier of apo E2 Kyoto and had dysbetalipoproteinemia, but no LPG. The pathophysiological effect of this mutation was investigated in vitro by binding studies of recombinant apo E2 Kyoto to LDL receptors on human fibroblasts. The ability of recombinant apo E2 Kyoto to displace LDL was reduced to 10% compared with recombinant apo E3. CONCLUSIONS: Apo E2 (Arg25Cys) Kyoto is a novel mutation of apo E that is etiologically related to LPG. However, our case indicates that the development of LPG may involve other genetic or environmental factors. Furthermore, our data suggest that arginine-25 of apo E plays an important functional role by influencing the receptor-binding ability of apo E.

Adult↗
PubMed1999

Disturbance of genetic information by a ribonucleotide analogue.

The synthetic base analogue, 6H,8H-3,4-dihydropyrimido[4,5-c][1,2]oxazin-7-one (P), can efficiently base pair with A and G. We have previously demonstrated that the deoxyribonucleoside of P (dP) is highly mutagenic and that this is due to the ambiguous base pairing ability of P. In this work, we have shown that the ribonucleoside triphosphate of P (rPTP) induces C to U mutation on an in vitro model of retroviral genomic RNA replication pathway. This mutation induction by rPTP may be specific to retroviruses, since host genomic DNA should not be affected by such a ribonucleotide analogue, although temporary transcription-translation errors may occur.

Adenine↗
PubMed1999

Pulsatile peptide release from multi-layered hydrogel formulations consisting of poly(ethylene glycol)-grafted and ungrafted dextrans.

Multi-layered hydrogel formulations consisting of poly(ethylene glycol)-grafted dextran (PEG-g-Dex) and ungrafted Dex were investigated as a model of pulsatile drug release. In these formulations, it is considered that the grafted PEG domains act as a drug reservoir dispersed in the Dex matrix based on aqueous polymer two-phase systems. The formulations exhibited surface-controlled degradation by dextranase, and insulin release was observed in a pulsatile manner because of the multi-layered structure: PEG-g-Dex hydrogel layers containing insulin and insulin-free Dex hydrogel layers. Thus, it is suggested that the multi-layered hydrogel formulations using PEG-g-Dex and Dex are feasible for chronopharmacological drug delivery systems.

Animals↗
PubMed1999

Evidence for apoptosis induction in myofibroblasts during palatal mucoperiosteal repair.

Apoptosis is thought to be a requisite event for maintaining kinetic homeostasis within continually renewing tissues such as the oral mucosa and skin. However, no systematic study of the apoptotic process in fibroblasts in the oral mucosa following injury has been performed. In this study, we have assessed the expression of transforming growth factor-beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF), which are among the most important modulators of wound repair, during wound healing following mucoperiosteal injury in the rat palate. In addition, we have investigated fibroblast differentiation and apoptosis by immunohistochemical analysis for alpha-smooth-muscle (alpha-SM) actin or DNA strand breaks, respectively, to clarify the mechanisms of the wound healing process. TGF-beta1-positive cells were noted in the subepithelium from Day 2 to Day 14 after injury, by which time the wounds were completely reepithelialized. Strong expression of bFGF was observed, mainly in macrophages and monocytes at the injured site, from Day 10 to Day 14 after injury. TGF-beta1 and bFGF-immunostaining was significantly lower during the later phase of wound healing. In addition, the number of myofibroblasts expressing alpha-SM actin increased (peak at Day 14), and thereafter gradually decreased. In parallel, the apoptosis in myofibroblasts was prominent on Day 14. These results suggest that TGF-beta1 and bFGF may be potential stimulators of apoptosis in myofibroblasts after re-epithelialization in the palatal wound healing process. The regulation of apoptotic phenomena during wound healing may be important in scar establishment and development of pathological scarring.

Actins↗
PubMed1999

Characterization of recombinant monoclonal antithyrotropin receptor antibodies (TSHRAbs) derived from lymphocytes of patients with Graves' disease: epitope and binding study of two stimulatory TSHRAbs.

Anti-TSH receptor autoantibodies (TSHRAbs) are known to be involved in Graves' disease. To elucidate the molecular mechanism of the pathogenesis of Graves' disease, we previously isolated and reconstituted the Ig genes of two B cell clones (101-2 and B6B7) producing a monoclonal thyroid-stimulating antibody (TSAb), a stimulating type of TSHRAb, obtained from patients with Graves' disease. In the present study, we produced a large amount of recombinant monoclonal TSAbs in eukariotic cells using these genes and characterized them. First, we tried to identify their epitopes in the TSHR, by using a panel of mutants of the extracellular domain of the TSH receptor (TSHR). Substantial cell surface expression level of each mutant was confirmed by fluorescence-activated cell sorter analysis using a TSHRAb. Mutations in the N-terminal (but not C-terminal) region of the extracellular domain of TSHR abrogated or reduced TSAb activities of both antibodies, whereas they had opposite effects on TSH activity; cAMP generation by 101-2 significantly decreased in the receptors mutated in amino acids 52-56 and 58-61, and that by B6B7 decreased in amino acids 34-37 and 58-61. Secondly, purified antibodies were radiolabeled and tested for binding to cells expressing high levels of TSHR. Although their affinities were lower than that of TSH, their binding was not displaced by TSH. The antibody binding was not mutually competitive. These findings suggest that these antibodies interact with the N-terminal region of the receptor and transduce a signal through binding sites different from TSH. We believe that this is the first report of the characterization of human monoclonal TSHRAbs on their epitopes and bindings, confirming previous reports using patient sera or murine monoclonal antibodies.

Amino Acid Sequence↗
PubMed1999

A case of Hashimoto's thyroiditis with markedly elevated serum thyroglobulin and evidence of its influence on the measurement of anti-thyroglobulin antibody by highly sensitive assays.

We present the case of a 66-year-old woman with Hashimoto's thyroiditis, who showed extremely high concentrations of serum thyroglobulin (Tg). Serum Tg levels were markedly elevated following a slight elevation of serum thyrotropin (TSH) (22,000 ng/mL and 11.1 microU/mL, respectively). Although elevated concentrations of serum Tg declined concomitant with decrease of serum TSH one month later, Tg concentrations remained high (> 948 ng/mL) even at normal or suppressed TSH levels. There was no evidence of massive thyroid tissue damage or thyroid tumor. To our knowledge, there have been no case reports of such high concentrations of serum Tg (> 2 x 10(4) ng/mL) in the clinical course of Hashimoto's thyroiditis. Furthermore, we showed evidence that extremely high Tg levels could possibly influence the measurement of anti-Tg autoantibody using highly sensitive radioimmunoassays.

Aged↗
PubMed1999

[Epstein-Barr virus associated Richter's syndrome accompanied by interstitial pneumonia].

A 65-year-old man who had an 8-year history of chronic lymphocytic leukemia was admitted to our hospital on February 19, 1998 because of high fever, dry cough, and weight loss. Laboratory data on admission included serum lactate dehydrogenase at 980 IU/l, CRP at 21.8 mg/dl, and soluble interleukin-2 receptor at 7,280 U/ml. The results of serological tests for Epstein-Barr virus (EBV) antibodies were as follows: EBV capsid antigen IgG 1:2560, EBV early antigen IgG 1:640, and EBV nuclear antigens 1:20. Computed tomography revealed diffuse interstitial pneumonia in both lungs, hepatosplenomegaly with multiple nodules, and enlarged intra-abdominal lymph nodes. In addition, Gallium-67 scintigraphy demonstrated abnormal accumulations. Although the patient initially responded well to combination chemotherapy, he eventually deteriorated and died on November 2, 1988, despite salvage chemotherapy. Postmortem needle biopsy specimens from the liver and spleen revealed diffuse proliferation of polymorphic large lymphoma cells. The lymphoma cells were positive for L-26, latent membrane protein 1, and EBV nuclear antigen, but negative for UCHL-1 and CD3, 5, 10, and 30. In situ hybridization procedures disclosed the presence of EBV-encoded small RNA in lymphoma cells. These findings suggested the possibility of association with EBV infection in some cases of Richter's syndrome.

Aged↗
PubMed1999

Long-term observation of subcutaneous tissue reaction to synthetic auditory ossicle (Bioceram) in rats.

To evaluate biocompatibility to tissue in long-term implantation, Bioceram discs made of aluminum oxide (Al2O3) were implanted subcutaneously within the interscapular region of 64 rats for six to 20 months. Histological sections stained with haematoxylin and eosin (H&E) and the surface of the implant material were observed using light microscopy. Different cell types and the thickness of fibrous capsules surrounding the implants were examined quantitatively by light microscopy. Small numbers of macrophages (2.8 +/- 0.7%) and lymphocytes (2.7 +/- 0.9%) were observed at six months after implantation, gradually decreasing to zero at 16, 18 and 20 months. Neither neutrophils nor foreign body giant cells were seen in any specimens. The thickness of fibrous capsules surrounding the implants was closely related to the shape of the implant, but there was no significant change between six and 20 months after implantation. No change in Bioceram surfaces were observed under stereoscopic microscopy from six to 20 months after implantation. The study results indicate that Bioceram is a satisfactory biocompatible material for reconstructive surgery from the viewpoint of long-term tissue response. Present results of experiments with Bioceram are also compared to previous results with Apaceram and different tissue responses of the two materials are discussed.

Aluminum Oxide↗
PubMed1999

Amount of metallic ions released from Ti-Ni alloy by abrasion in simulated bioliquids.

The current density of Ti-56mass%Ni (Ti-50at.%) alloy after abrasion in simulated bioliquids was measured using a potentiostat to estimate the amount of metallic ions released from the alloy during repassivation and maturation. The current density in saline, saline with and without N2 bubbling, and Hanks' solutions with and without proteins after abrasion was measured and the amount of released ion was calculated from the integrated current density with time, assuming that Ti4+ and Ni2+ are equivalently released. No difference in the amount of released ion was observed between saline with and without N2 bubbling. Also, no difference was observed between saline and pH 7.4 Hanks' solution. More Ti4+ and Ni2+ were released in bioliquids with proteins than in saline with and without N2 bubbling (p < 0.05). That is, dissolved oxygen and inorganic ions in Hanks' solution did not influence the amount of released ion, but proteins influenced it. The release of metallic ions from metals and alloys in biological systems can be estimated by the methodology employed in this study.

Alloys↗
PubMed1998

Matrilysin-specific antisense oligonucleotide inhibits liver metastasis of human colon cancer cells in a nude mouse model.

Human colon cancer frequently develops liver metastasis. Matrilysin (MMP-7), the smallest member of the matrix metalloproteinase (MMP) family, is commonly produced by human colon carcinoma cells and has been suggested to be involved in the progression and metastasis of this type of cancer. In the present study, we tested the effect of a matrilysin-specific antisense phosphorothioate oligonucleotide on liver metastasis of the human colon carcinoma cell line WiDr in nude mice. In culture, the antisense oligonucleotide moderately inhibited the secretion of matrilysin by WiDr cells. Injection of WiDr cells into the spleen of nude mice produced many metastatic tumor nodules in the liver. When the antisense oligonucleotide was injected daily into the mice for 11 days, the formation of the metastatic tumor nodules was strongly inhibited in a dose-dependent manner. An inhibition of liver metastasis of over 70% was obtained at a dose of 120 micrograms of the oligonucleotide per mouse. The antisense oligonucleotide did not inhibit tumor growth in spleen and in liver. A scrambled control oligonucleotide had no effect on liver metastasis of WiDr cells. Our results demonstrate an important role of matrilysin in liver metastasis of human colon cancer and the therapeutic potential of matrilysin antisense oligonucleotides for the prevention of metastasis.

Aged↗
PubMed1998

Synthesis and RNA polymerase incorporation of the degenerate ribonucleotide analogue rPTP.

The synthesis and enzymatic incorporation into RNA of the hydrogen bond degenerate nucleoside analogue 6-(beta-d-ribofuranosyl)-3, 4-dihydro-8H-pyrimido[4,5-c]-[1,2]oxazin-7-one (P) is described. The 5'-triphosphate of this analogue is readily incorporated by T3, T7 and SP6 RNA polymerases into RNA transcripts, being best incorporated in place of UTP, but also in place of CTP. When all the uridine residues in an HIV-1 TAR RNA transcript are replaced by P the transcript has similar characteristics to the wild-type TAR RNA, as demonstrated by similar melting temperatures and CD spectra. The P-substituted TAR transcript binds to the Tat peptide ADP-1 with only 4-fold lowered efficiency compared with wild-type TAR.

Base Sequence↗
PubMed1998

Role of tissue inhibitor of metalloproteinases-2 (TIMP-2) in regulation of pro-gelatinase A activation catalyzed by membrane-type matrix metalloproteinase-1 (MT1-MMP) in human cancer cells.

To clarify the regulatory mechanism of pro-gelatinase A (proGelA) activation at a cellular level, expression of gelatinase A (GelA), three MT-MMPs, and TIMP-2 was examined with 11 human cancer cell lines cultured in the presence and absence of stimulants. MT1-MMP mRNA was expressed in 8 cell lines, while MT2-MMP and MT3-MMP mRNAs were expressed in fewer cell lines. The cells with high proGelA activation strongly expressed MT1-MMP mRNA but not MT2-MMP and MT3-MMP mRNAs, suggesting that MT1-MMP was responsible for the proGelA activation in the cancer cells. Treatments with concanavalin A (Con A) and a phorbor ester (TPA) enhanced the MT1-MMP expression, but only Con A stimulated the proGelA activation in many cell lines. In HT1080 fibrosarcoma cells, however, TPA also stimulated the activation. The level of TIMP-2 secreted into culture medium inversely correlated with proGelA activation. For example, 2 squamous cell carcinoma lines (HSC-3 and HSC-4) and 3 HT1080 clones, which efficiently activated proGelA, secreted little TIMP-2 into medium, whereas other cell lines and other HT1080 clones, which hardly activated proGelA, secreted TIMP-2 at high levels. When HSC-3 cells were incubated with TIMP-2 protein or transfected with TIMP-2 cDNA, the proGelA activation was strongly inhibited. These results indicated that extracellular TIMP-2 was an important negative regulator of proGelA activation. However, the level of extracellular TIMP-2 was not consistent with that of TIMP-2 mRNA in some cell lines. Other experimental results suggested that TIMP-2 might be rapidly metabolized after binding to MT1-MMP, and Con A treatment might stabilize the complex of TIMP-2 and MT1-MMP on cell membranes.

Catalysis↗