Biomedical subjects

M Mizuno

Publications and source records attributed to M Mizuno.

At least 37 records · Page 2Linked to original sources

PubMed2003

In vitro effect of platelet-derived growth factor-BB on collagen synthesis and proliferation of human periodontal ligament cells.

OBJECTIVES: Platelet-derived growth factor (PDGF)-BB is a polypeptide growth factor which has been shown to stimulate periodontal regeneration. In this study, we investigated the time- and dose-dependent effect of PDGF-BB on the proliferation and collagen synthesis of human periodontal ligament (PDL) cells. MATERIALS AND METHODS: For the proliferation assay, PDL cells were cultured in 0.01-10 ng ml(-1) of PDGF-BB for 12 or 24 h, and cell numbers were counted. For the collagen synthesis assay, PDL cells were cultured in 0.1-10 ng ml(-1) of PDGF-BB for 1 to 24 h. The ratio of collagen content in total protein was evaluated, and the gene expression of type I collagen was assessed quantitatively by Northern blotting analysis. RESULT AND CONCLUSIONS: PDGF-BB stimulated the proliferation of PDL cells in a time- and dose-dependent manner with the maximum effect at 10 ng ml(-1). PDGF-BB induced the collagen synthesis of PDL cells with the maximum effect for 24-h treatment, and 1 ng ml(-1) of PDGF-BB. PDGF-BB exhibits an inverse dose-dependent effect on proliferation and collagen synthesis by PDL cells. These findings suggest that PDGF-BB is one of the important regulators of the maintenance of the extracellular matrix in PDL, and may play an important role in the regeneration of PDL.

Becaplermin↗

PubMed2003

Phosphatidylinositol 3-kinase: a molecule mediating BDNF-dependent spatial memory formation.

Brain-derived neurotrophic factor (BDNF) plays a critical role in synaptic plasticity such as long-term potentiation (LTP), a form of synaptic correlate of learning and memory. BDNF is also implicated in learning and memory. We have demonstrated that radial arm maze training in rats for spatial learning and memory results in a significant increase in the BDNF mRNA expression in the hippocampus. Moreover, antisense BDNF oligonucleotide treatment impaired not only acquisition, but also maintenance and/or recall of spatial memory in the maze. Although these results suggest a role of BDNF for spatial memory processes, the signal transduction mechanisms that mediate the actions of BDNF remain unknown. Here we show that phosphorylation of BDNF receptor tyrosine kinase B (TrkB), phosphatidylinositol 3-kinase (PI3-K) and Akt, a target of PI3-K, in the hippocampus increased in parallel with spatial memory formation. Moreover, an activation of translational processes was suggested in the hippocampus after the maze training. When spatial learning was inhibited by antisense BDNF oligodeoxynucleotide, the activation was diminished. Chronic treatment with PI3-K inhibitor wortmannin impaired spatial learning. Our findings suggested that activation of TrkB/PI3-K and protein synthesis signaling pathway by BDNF in the hippocampus is important for spatial memory.

Androstadienes↗

PubMed2003

Tyrosine nitration of a synaptic protein synaptophysin contributes to amyloid beta-peptide-induced cholinergic dysfunction.

Amyloid beta (Abeta) is a critical factor involved in the pathogenesis of Alzheimer's disease (AD). We have previously demonstrated that continuous intracerebroventricular infusion of Abeta1-40 induced a time-dependent expression of the inducible nitric oxide (NO) synthase (iNOS) and an overproduction of NO in the rat hippocampus. The pathophysiological significance of the overproduction of NO on brain function was manifested by an impairment of nicotine-evoked acetylcholine(ACh) release and memory deficits.(4) Molecular mechanisms by which NO participates in the Abeta-induced brain dysfunction, however, remain to be determined. Here we show that chronic Abeta1-40 infusion caused a robust peroxynitrite formation and subsequent tyrosine nitration of proteins in the hippocampus. Immunoprecipitation and Western blot analyses further revealed that synaptophysin, a synaptic protein, was a main target of tyrosine nitration. Chronic infusion of Abeta1-40 resulted in an impairment of nicotine-evoked ACh release as analyzed by microdialysis. Daily treatment with the iNOS inhibitor aminoguanidine (AG) or the peroxynitrite scavenger uric acid (UA) prevented the tyrosine nitration of synaptophysin as well as the impairment of nicotine-evoked ACh release induced by Abeta. Our findings suggest that the tyrosine nitration of synaptophysin is related to Abeta-induced impairment of ACh release.

Acetylcholine↗

PubMed2003

Influence of abutment substrates on the colour of metal-free polymer crowns.

New-generation composite materials have excellent strength and wear resistance, and thus can be used to make metal-free crowns. However, composite materials are translucent, and so when using them to make metal-free crowns, it is necessary to take the effect of the abutments into consideration. In this study, five types of materials including three types of new-generation composite materials, a conventional composite material, and a ceramic material were used to examine the translucency (contrast ratio) of the materials and the effects of the colour of the abutments on the final appearance of metal-free crowns. It was found that the materials varied slightly from one-another in translucency and that it was possible to reproduce the desired colour when gold alloy was used for the background. However, it was difficult to produce an adequate colour match when silver-palladium alloy was used for the background. When a tooth colour material that was darker than the target colour was used for the abutment teeth, some materials could not reproduce the target colour satisfactorily.

Composite Resins↗

PubMed2003

A proton-pump inhibitor, rabeprazole, improves ventilatory function in patients with asthma associated with gastroesophageal reflux.

BACKGROUND: Treatment of gastroesophageal reflux (GER) with proton-pump inhibitors (PPI) improves symptoms of asthma in some patients. However, the effects of a PPI on ventilatory function are still controversial. In this study, we measured ventilatory function in asthma patients treated with a PPI in order to identify those in whom a therapeutic effect on asthma can be expected from the acid suppression. METHODS: From a cohort of 114 consecutive patients with bronchial asthma, 53 patients agreed to participate in the study and were treated with rabeprazole 20mg daily for 8 weeks during an asymptomatic, stable period with no exacerbations of their asthma. Of the 53 patients, 22 were diagnosed as GER on the basis of the QUEST questionnaire and endoscopic examination. The patients were monitored for improvement in ventilatory function. RESULTS: Four patients dropped out because of adverse drug reactions. All the patients with GER noted an improvement in reflux symptoms with PPI treatment. An improvement of more than 20% in peak expiratory flow (PEF) was observed in 8 of 21 GER patients but in none of the non-GER patients. Factors predictive of improvement in PEF with rabeprazole therapy were the QUEST score (odds ratio: 1.47, 95% CI: 1.06-2.04, P = 0.022) and steroid-dependency of asthma (odds ratio: 0.01, 95% CI: 0.001-0.31, P = 0.008). CONCLUSIONS: Treatment with rabeprazole is expected to ameliorate asthma in non-steroid-dependent patients who have symptomatic GER defined by the QUEST score.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2002

Electronic state of small and large cavities for methane hydrate.

It is well known that methane hydrate is aggregates of small and large hydrogen bonded water cavities (composed of 12 pentagonal faces of 20 water molecules, and 12 pentagonal and two hexagonal faces of 24 water molecules, respectively) where one methane molecule is encaged. We calculated the methane molecule in vacuum, the small and large cavities by ab initio MO method to clarify the electronic state. The proton of methane in the cavities is shown to form the weak hydrogen bond (O...H[bond]C) between methane and four water molecules, and the H-bond lengths and energies in the small and large cavities were estimated as (0.293 nm, 6.8 kJ/mol) and (0.309 nm, 5.2 kJ/mol), respectively. The calculated values of symmetric C[bond]H stretching frequencies and (13)C-NMR chemical shieldings of the methane in the two cluster cavities show good agreement with the experimental ones observed by Sum et al. and Ripmeester and coworker, respectively.

Journal Article↗

PubMed2002

Process of apoptosis induced by TNF-alpha in murine fibroblast Ltk-cells: continuous observation with video enhanced contrast microscopy.

Apoptosis is originally defined by unique morphological changes of dying cells, and the biochemical hallmark associated with apoptosis is internucleosomal DNA fragmentation. However, few report has shown the precise time course of the apoptotic events. The present study was designed to try to clarify apoptotic processes using a video-enhanced contrast-differential interference contrast (VEC-DIC) microscopy. The morphological changes of murine fibroblast Ltk-cells treated with TNF-alpha were divided into four stages: (i) pre-apoptotic, (ii) cytoplasmic shrinkage, (iii) membrane blebbing, and (iv) ballooning. Almost of the cells underwent cytoplasmic shrinkage and membrane blebbing within 6 hours after TNF-alpha exposure, and at about 9 hours, they were in the ballooning stage. Based on these data, we investigated the relationship between morphological changes and other biochemical features. The earliest event was exposure of phosphatidyl-serine at the cytoplasmic membrane, which was already observed in the pre-apoptotic stage. Loss of mitochondrial membrane potential was observed in the cytoplasmic shrinkage stage. Caspase-8/-3 activities already started increasing in the pre-apoptotic stage, and reached their peak at 6 hours after TNF-alpha exposure. DNA fragmentation occurred in the late phase of the membrane blebbing.

Animals↗

PubMed2002

Enhanced expression of decay-accelerating factor and CD59/homologous restriction factor 20 in intestinal metaplasia, gastric adenomas and intestinal-type gastric carcinomas but not in diffuse-type carcinomas.

AIMS: Variable expression of the complement regulatory proteins, decay-accelerating factor, CD59/homologous restriction factor 20 (HRF20) and membrane cofactor protein has been shown in human gastrointestinal malignancies, but their expression in gastric cancer has not been fully described. Thus, we immunohistochemically defined the distribution of these proteins in human normal gastric mucosa, intestinal metaplasia, adenomas and gastric cancers. METHODS AND RESULTS: Gastric tissues were obtained by endoscopic biopsy or surgical resection and stained with mouse monoclonal antibodies to decay-accelerating factor, CD59/HRF20, and membrane cofactor protein. In the normal gastric mucosa, membrane cofactor protein was diffusely stained on the basolateral surface of epithelial cells, whereas the expression of decay-accelerating factor and CD59/HRF20 was inconspicuous. In intestinal metaplasia, adenoma and intestinal-type gastric carcinoma cells, decay-accelerating factor and HRF20 were intensely stained on the apical surface; membrane cofactor protein retained its location on the basolateral surface. In diffuse-type gastric carcinomas, the expression of decay-accelerating factor, CD59/HRF20 was lost, but membrane cofactor protein was present on the tumour cell surface. CONCLUSIONS: These findings suggest that membrane cofactor protein plays a primary role in the regulation of complement activation in normal and neoplastic gastric cells and that the expression pattern of the complement regulatory proteins is closely related to gastric carcinoma development.

Adenoma↗

PubMed2002

Serrated adenoma in familial adenomatous polyposis: relation to germline APC gene mutation.

BACKGROUND: Serrated adenoma is a precursor of colorectal cancer. AIM: To clarify possible genotype-phenotype correlations of serrated adenomas in familial adenomatous polyposis (FAP). PATIENTS: Eleven patients from eight families with FAP. METHODS: We performed total colonoscopy with multiple biopsies in patients. Neoplasia with a serrated glandular structure was regarded as a serrated adenoma. In each patient, germline mutations of the APC gene were determined. Colonic phenotype was compared with germline mutations of the APC gene. RESULTS: Serrated adenomas were found in three patients. These patients had macroscopic polyps <100 in number. Pedigrees with serrated adenomas had the truncating germline APC mutation at codon 161, 332, or 1556 while in the other pedigrees mutations were found between codons 554 and 1324. CONCLUSIONS: In FAP, serrated adenoma may be a phenotype characteristic of the attenuated form.

Adenoma↗

PubMed2001

Timing of postexercise protein intake is important for muscle hypertrophy with resistance training in elderly humans.

1. Age-associated loss of skeletal muscle mass and strength can partly be counteracted by resistance training, causing a net synthesis of muscular proteins. Protein synthesis is influenced synergistically by postexercise amino acid supplementation, but the importance of the timing of protein intake remains unresolved. 2. The study investigated the importance of immediate (P0) or delayed (P2) intake of an oral protein supplement upon muscle hypertrophy and strength over a period of resistance training in elderly males. 3. Thirteen men (age, 74 +/- 1 years; body mass index (BMI), 25 +/- 1 kg m(-2) (means +/- S.E.M.)) completed a 12 week resistance training programme (3 times per week) receiving oral protein in liquid form (10 g protein, 7 g carbohydrate, 3 g fat) immediately after (P0) or 2 h after (P2) each training session. Muscle hypertrophy was evaluated by magnetic resonance imaging (MRI) and from muscle biopsies and muscle strength was determined using dynamic and isokinetic strength measurements. Body composition was determined from dual-energy X-ray absorptiometry (DEXA) and food records were obtained over 4 days. The plasma insulin response to protein supplementation was also determined. 4. In response to training, the cross-sectional area of m. quadriceps femoris (54.6 +/- 0.5 to 58.3 +/- 0.5 cm(2)) and mean fibre area (4047 +/- 320 to 5019 +/- 615 microm(2)) increased in the P0 group, whereas no significant increase was observed in P2. For P0 both dynamic and isokinetic strength increased, by 46 and 15 %, respectively (P < 0.05), whereas P2 only improved in dynamic strength, by 36 % (P < 0.05). No differences in glucose or insulin response were observed between protein intake at 0 and 2 h postexercise. 5. We conclude that early intake of an oral protein supplement after resistance training is important for the development of hypertrophy in skeletal muscle of elderly men in response to resistance training.

Aged↗

PubMed2001

Chemo-enzymatic synthesis of a bioactive peptide containing a glutamine-linked oligosaccharide and its characterization.

A bioactive peptide containing a glutamine-linked oligosaccharide was chemo-enzymatically synthesized by use of the solid-phase method of peptide synthesis and the transglycosylation activity of endo-beta-N-acetylglucosaminidase. Substance P, a neuropeptide, is an undecapeptide containing two L-glutamine residues. A substance P derivative with an N-acetyl-D-glucosamine residue attached to the fifth or sixth L-glutamine residue from the N-terminal region was chemically synthesized. A sialo complex-type oligosaccharide derived from a glycopeptide of hen egg yolk was added to the N-acetyl-D-glucosamine moiety of the substance P derivative using the transglycosylation activity of endo-beta-N-acetylglucosaminidase from Mucor hiemalis, and a substance P derivative with a sialo complex-type oligosaccharide attached to the L-glutamine residue was synthesized. This glycosylated substance P was biologically active, although the activity was rather low, and stable against peptidase digestion. The oligosaccharide moiety attached to the L-glutamine residue of the peptide was not liberated by peptide-N(4)-(N-acetyl-beta-D-glucosaminyl) asparagine amidase F.

Amidohydrolases↗

PubMed2001

Association between a polymorphism of the transforming growth factor-beta1 gene and genetic susceptibility to ossification of the posterior longitudinal ligament in Japanese patients.

STUDY DESIGN: A study was conducted to determine the association between polymorphism of the transforming growth factor-beta1 (TGF-beta1) gene and ossification of the posterior longitudinal ligament (OPLL) prevalence. OBJECTIVE: To examine whether the T869-->C polymorphism of the TGF-beta1 gene is associated with genetic susceptibility to OPLL in Japanese subjects. SUMMARY OF BACKGROUND DATA: In the posterior longitudinal ligament, OPLL is associated with abnormal calcium metabolism. Several candidate genes are associated with the prevalence of OPLL. In the ossified matrix and chondrocytes of adjacent cartilaginous areas of OPLL, TGF-beta1 is overexpressed. METHODS: The TGF-beta1 genotype was identified with an allele-specific polymerase chain reaction method in 319 Japanese subjects (46 subjects with OPLL and 273 control subjects). RESULTS: There was a significant association between the T869-->C genotype and the prevalence of OPLL in the cervical spine. Multivariable logistic regression analysis, adjusted for gender, age, height, and body weight, showed that the frequency of the C allele was significantly higher in subjects with OPLL than in control subjects. CONCLUSIONS: The T869-->C polymorphism of the TGF-beta1 gene is a genetic determinant of a predisposition to OPLL, with the C allele representing a risk factor for genetic susceptibility to OPLL in Japanese subjects. Therefore, TGF-beta1 genotyping may be useful in the prevention of OPLL.

Aged↗

PubMed2001

3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) induces caspase-dependent apoptosis in mononuclear cells.

3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), one of the tryptophan pyrolysates, is a dietary carcinogen and is formed in cooked meat and fish in our daily diet. Trp-P-1 will affect the cells in the blood circulation system before it causes carcinogenicity in target organs such as the liver. In this study, the cytotoxicity of Trp-P-1 was investigated in mononuclear cells (MNCs) from blood. Trp-P-1 (10-15 microM) decreased cell viability and induced apoptosis characterized both by morphological changes and by DNA fragmentation 4 h after treatment. DNA fragmentation was also observed following treatment at 1 nM after 24 h in culture. This result suggested that apoptosis would occur in the body following unexpected intake of foods containing Trp-P-1. To determine the mechanism of apoptosis, we investigated the activation of the caspase cascade in MNCs. Trp-P-1 (10-15 microM) activated the caspase cascade, i.e. the activity of caspase-3, -6, -7, -8 and -9 increased dose-dependently using peptide substrates, the active forms of caspase-3, -8 and -9 were detected by immunoblotting, and cleavage of poly(ADP-ribose) polymerase and protein kinase C-delta as the intracellular substrates for caspases was observed. A peptide inhibitor of caspase-8 completely suppressed activation of all other caspases, while an inhibitor of caspase-9 did not. These results indicated that caspase-8 may act as an apical caspase in the Trp-P-1-activated cascade.

Acetylcysteine↗

PubMed2001

Rat glioma cell death induced by cationic liposome-mediated transfer of the herpes simplex virus thymidine kinase gene followed by ganciclovir treatment.

BACKGROUND AND OBJECTIVES: We studied antitumor effects and cell death induced by cationic liposome-mediated gene transfer of the herpes simplex virus thymidine kinase (HSV-tk) gene followed by ganciclovir treatment in cultured rat T9 glioma cells and in experimental gliomas produced from this cell line. METHODS: To transfer genes we used small unilamellar cationic liposomes containing N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride. Video-enhanced contrast differential interference contrast microscopy was used for morphologic observations of cultured cells. RESULTS: When we treated the cells or implanted gliomas with the liposomes and ganciclovir, a strong effect was seen against tumor cells, and survival of tumor-implanted rats was increased. Morphologically, cell death observed after HSV-tk gene/liposome and ganciclovir treatment in the cultured glioma cells included both apoptosis and necrosis. CONCLUSIONS: Introduction of the HSV-tk gene in a DNA-liposome complex followed by ganciclovir treatment induced both apoptosis and necrosis, which together resulted in a potent antitumor effect.

Animals↗

PubMed2001

Membrane complement regulators protect against the development of type II collagen-induced arthritis in rats.

OBJECTIVE: To investigate changes in the distribution patterns of membrane complement regulators (MCRs) during the development of type II collagen-induced arthritis (CIA) and to examine the protective effects of these molecules against the augmentation of CIA in the knee joint. METHODS: Immunohistochemistry was used to examine the distribution of the MCRs Crry, DAF, and CD59 in the synovium of knee joints before and 2, 4, and 10 weeks after induction of CIA by immunization with type II collagen. In addition, at 2 or 10 weeks after induction of CIA, rats were injected intraarticularly with anti-Crry and/or anti-CD59 as the F(ab')2 fraction of monoclonal antibodies (mAb). Knee joint swelling and histologic changes in the synovium were examined 2 weeks after mAb injection. RESULTS: Synovial expression of Crry, DAF, and CD59 decreased in parallel with increased inflammation. When Crry and CD59 were functionally blocked at 2 weeks after the induction of CIA, swelling of the knee joints was markedly increased. Blocking of either regulator alone had no effect on swelling. Thickening of the synovial surface and proliferation of subsynovial tissue were all increased after blocking Crry and CD59, whereas blocking of either MCR alone had no effect. When both Crry and CD59 were blocked, deposits of membrane attack complex were found in the synovium. CONCLUSION: Our findings indicate that in rats with CIA and severely inflamed synovium, local expression of MCR is reduced. The MCRs Crry and CD59 appear to suppress the development of CIA.

Animals↗

PubMed2001

Intratumoral microinfusion of nimustine (ACNU) for recurrent glioma.

We investigated stereotactic intratumoral microinfusion of nimustine (ACNU) in recurrent brain tumors. Eligibility required histologic confirmation of glioma recurrence despite standard radiotherapy and chemotherapy as well as enhancement of the recurrence with gadolinium on magnetic resonance imaging (MRI). A total intratumoral dose of 10 mg of ACNU was administered continuously with a microinfusion pump over an average of 13h. Fifteen infusions were given in nine patients. All patients completed the treatment safely. On MRI, necrotic changes surrounded the infusion area in all patients, and tumor progression was inhibited or performance score was improved in seven of nine patients. No symptomatic systemic toxicity was evident, although one patient developed permanent left oculomotor palsy locally after treatment of a left medial temporal tumor. It is concluded that direct microinfusion of ACNU into recurrent gliomas can induce tumor necrosis and inhibit tumor growth.

Adult↗

PubMed2001

Association of the C-509-->T polymorphism, alone of in combination with the T869-->C polymorphism, of the transforming growth factor-beta1 gene with bone mineral density and genetic susceptibility to osteoporosis in Japanese women.

Transforming growth factor-beta1 is an important local regulator of bone metabolism, acting downstream of estrogen and cooperatively with vitamin D. The possible association of a C 509-->T polymorphism in the promoter region of the transforming growth factor-beta1 gene, alone or in combination with a T869-->C (Leu10-->Pro) polymorphism, with bone mineral density and genetic susceptibility to osteoporosis was investigated in 625 postmenopausal Japanese women. The frequencies of the CC, CT, and TT genotypes of the C-509-->T polymorphism in the study population were 24%, 49%, and 27%, respectively. A significant association of C-509-->T genotype with bone mineral density was detected: lumbar spine (L2-L4) and total body bone mineral density values were 7% and 5% lower, respectively, in individuals with the TT genotype than in those with the CT or CC genotype. The serum concentration of transforming growth factor-beta1 did not vary with C-509-->T genotype. Multivariable logistic regression analysis, with adjustment for age, height, body weight, time since menopause, smoking status, body fat mass, and lean mass, revealed a significantly higher frequency of the TT genotype of the C-509-->T polymorphism in 286 individuals with osteoporosis than in 170 normal controls. Analysis of combined C-509-->T and T869-->C genotypes showed that L2-L4 bone mineral density decreases and the prevalence of osteoporosis increases with the number of T alleles. These results suggest that the C-509-->T polymorphism, alone or in combination with the T869-->C polymorphism, of the transforming growth factor-beta1 gene is a genetic determinant of bone mass, and that the number of T alleles in the combined genotype is a risk factor for the genetic susceptibility to osteoporosis in postmenopausal Japanese women.

Aged↗

PubMed2001

Hip fracture prevention trial using hip protectors in Japanese nursing homes.

A method to protect the hips during falls could effectively reduce the incidence of hip fractures. We report the results of the first hip protector trial in Japan, performed between July 1996, and September 1999. One hundred and sixty-four elderly female residents of nursing homes, with Activities of Daily Living above the wheelchair level, agreed to participate in this study. Among them, 88 were randomly selected to wear a hip protector and 76 controls did not. All falls and resulting injuries were recorded daily. In anthropometric measurements and ultrasonic bone evaluation, no significant differences were found between the two groups, except in height. During an average of 377 days, the wearers and the non-wearers fell a total of 131 and 90 times, respectively. Among the wearers, there were two non-hip fractures and one hip fracture, so the annual hip fracture rate was calculated at 1.2%, against 8 hip fractures among the non-wearers, or 9.7% per year. The hip fracture rate was significantly lower among the wearers than non-wearers, while the annual number of falls per subject and the distribution of fallers remained the same. According to Cox's proportional hazard regression analysis, the effect of the hip protector on hip fracture prevention was independent of anthropometric data, ultrasonic bone assessment values or number of falls. Moreover, even after limiting the subjects to fallers only, the annual hip fracture rate in non-wearers was higher than in wearers (19.8% vs 2.0%) and the annual hip fracture rate per fall in wearers was lower than that in non-wearers (0.8% vs 8.2%). It was thus concluded that the hip protector is a beneficial device for the prevention of hip fractures.

Accidental Falls↗