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Biomedical subjects

H Miyazaki

Publications and source records attributed to H Miyazaki.

At least 37 records · Page 2Linked to original sources
PubMed2004

Fluoride mouth rinsing proficiency of Japanese preschool-aged children.

AIM: To determine whether Japanese preschool-aged children swallow fluoride solution while rinsing and how much fluoride was retained in the mouth after rinsing. METHODS: The subjects were 769 children who participated in a school-based fluoride mouth rinse programme (FMR) using 0.05% sodium fluoride solution daily. The group of younger, mean age of 4 years and 10 months, experienced the FMR for two months, and the group of older children, mean age of 5 years and 4 months, did it for at least 8 months, rinsing for a minute using 7 ml of the solution. The amount of fluoride retained in the mouth was estimated as the amount present in the net rinsing solution prepared minus what returned to the solution expectorated. RESULTS: No child swallowed all the solution. The rate of fluoride retained was 12.0% (mean = 0.19 mg) in the younger group and 10.7% (mean = 0.17 mg) in the older. Only six children retained over 0.5 mg of fluoride. With the extra survey using weekly intervals, the amount retained was below 0.5 mg in all children. CONCLUSION: That Japanese preschoolaged children could perform fluoride mouth rinsing safely and efficiently.

Age Factors↗
PubMed2004

The perforin mediated apoptotic pathway in lung injury and fibrosis.

AIMS: The perforin mediated pathway is the major pathway of cytotoxicity induced by activated T cells and natural killer cells, and may be involved in the development of pulmonary fibrosis. METHODS: Perforin and granzyme B expression were examined in idiopathic pulmonary fibrosis by means of immunohistochemistry, and perforin knockout mice were used to examine whether or not perforin mediated cytotoxicity participates in the pathophysiology of bleomycin induced pneumopathy. RESULTS: Perforin and granzyme B expression were upregulated in infiltrating lymphocytes in lung tissue from patients with idiopathic pulmonary fibrosis compared with normal lung parenchyma. Perforin and granzyme B expression were upregulated predominantly in infiltrating mononuclear cells after bleomycin instillation in wild-type mice. Although the development of bleomycin induced pneumopathy was not completely prevented, the pathological grade of inflammation and fibrosis, and the number of apoptotic cells in lung tissue, were significantly decreased in perforin knockout mice compared with wild-type mice. CONCLUSIONS: These results suggest that perforin mediated apoptosis may be associated with the pathophysiology of lung injury and fibrosis.

Animals↗
PubMed2003

Geometrical, functional, and histomorphometric adaptation of rat carotid artery in induced hypertension.

Acute and long-term (up to 56 days) evolution of geometry, structural properties, vascular smooth muscle (VSM) tone and histomorphometric properties of the rat common carotid arteries under induced hypertension were investigated. Hypertension was induced in 8-week old male Wistar rats by total ligation of the aorta between the two kidneys. Rats were sacrificed 2, 4, 8 and 56 days postsurgery. The arterial wall layers thicken non-uniformly during the adaptation process, the inner layers thicken more in the acute phase of hypertension, whereas the outer layers of the wall are thicker than the inner layers at the end of the adaptation phase. Collagen content in the wall media exhibits a non-linear evolution, with a rapid increase in the acute hypertension phase followed by a slower increase at long-term. The elastin content increase is slight and steady, whereas VSM shows a steady but considerable increase which outdoes the collagen increase in long-term phase. VSM tone increases rapidly in the acute phase of remodelling (0-8 days) and this increase in tone contributes to a considerable increase in arterial compliance in the operating pressure range. At long-term (56 days) VSM tone returns to near control level, but compliance is even further increased, which suggests that at long-term the compliance increase is attributed primarily to structural remodelling.

Adaptation, Physiological↗
PubMed2003

Breath malodor in an asthmatic patient caused by side-effects of medication: a case report and review of the literature.

OBJECTIVE: The purpose of this report is to document the presence of dimethyl sulfide in mouth air as the predominant volatile sulfur compound (VSC) in an asthmatic patient who was regularly taking suplatast tosilate. STUDY DESIGN: The patient was a 33-year-old woman who complained of bad breath. She had been diagnosed as having asthma and was receiving periodical medical examinations once a month. VSC in her mouth air were measured with a gas chromatograph. Oral physiotherapy was also carried out to remove any oral malodor of which the source was intraoral. RESULTS: With the improvement in oral hygiene and periodontal conditions, the level of VSC was reduced but dimethyl sulfide still remained as the predominant VSC. CONCLUSIONS: Dimethyl sulfide metabolized from suplatast tosilate may be a potential cause of halitosis.

Adult↗
PubMed2003

Socio-demographic risk indicators for tooth mortality in rural Sri Lankans.

To explore the socio-demographic factors associated with tooth loss in rural inhabitants of Sri Lanka, a random sample of 2178 males aged 20-60 years was selected using multi-stage cluster sampling procedure. The number of missing and present teeth was recorded excluding third molars and the subjects were interviewed to elicit socio-demographic information as well as oral hygiene and tobacco consumption habits. The mean number of teeth lost in the sample was 5.17 +/- 5.43. Tooth loss increased significantly with age. Sinhalese had significantly fewer lost teeth (5.05 +/- 5.38) compared to Tamils (6.54 +/- 6.18) and Muslims (6.02 +/- 5.21) whereas education, income, oral hygiene practices and tobacco use were significantly associated with tooth loss in the bivariate analysis. A forward stepwise multiple regression analysis revealed that age, Muslim ethnicity and quantified tobacco use were positively associated with tooth loss while better socio-economic conditions and good oral hygiene habits were negatively linked with tooth mortality independent of other factors. Age, Muslim ethnicity, quantified tobacco use, income, education, brushing frequency and substance used for cleaning had significantly affected tooth loss. Quantified tobacco use and oral hygiene may be regarded as modifiable socio-demographic risk indicators associated with tooth mortality in Sri Lankans.

Adult↗
PubMed2003

A pilot study of dental caries status in relation to knowledge, attitudes and practices in oral health in Myanmar.

This study was to determine the dental caries prevalence among the Myanmar population, and to investigate the correlations between oral clinical indices and knowledge, attitudes and practices (KAP) on oral health. Subjects were randomly selected from 140,000 people residing in the Kyauktan township in a cross-sectional community-based study. The present analysis was confined to 739 subjects (353 males and 386 females) aged 12, 35-44 and 65-74 years, who were divided into two specified groups based on urban or rural location. KAP on oral health data and social demographic information were collected, while dental caries status was assessed by DMFT. The mean number of decayed teeth (DT) in rural areas was higher than that in urban areas, while the mean number of filled teeth (FT) in rural areas was lower than that in urban areas. Mean knowledge and attitude scores for correct answers were also significantly higher for the urban than the rural subjects. There were statistically significant correlations between the correct/incorrect responses to knowledge and attitude questionnaires on oral health and the mean number of DMFT. KAP pertaining to oral health of Myanmar population, especially those of rural subjects, might not be satisfactory and related to threaten their dental caries status.

Adult↗
PubMed2003

Association between serum albumin and root caries in community-dwelling older adults.

Recently, associations between dental diseases and the general health condition have been reported. The purpose of this study was to evaluate, by serum albumin concentrations, the relationship between the general health condition and root caries. We randomly selected 763 individuals (600 70-year-olds and 163 80-year-olds) living in Niigata City, Japan. The variables body composition, blood measurements, daily nutrient intakes, and root caries were measured. The relationship between root caries and serum albumin concentration was evaluated. The differences in serum albumin concentrations between subjects with untreated root caries (DT = 0 and DT > 3) were 75.56 mg/dL in 70-year-olds and 202.97 mg/dL in 80-year-olds (p < 0.05, ANOVA). The findings of the present study indicated that a relationship between root caries and serum albumin concentration in these elderly subjects is highly possible.

Aged↗
PubMed2002

Biomechanical response of femoral vein to chronic elevation of blood pressure in rabbits.

Venous diseases like iliofemoral deep vein thrombosis and valvular dysfunction induce venous hypertension. To know the effects of the hypertension on venous mechanics, blood pressure in the left femoral vein in the rabbit was chronically elevated by the constriction of the left external iliac vein. Wall dimensions and biomechanical properties of the femoral vein were studied in vitro at 1, 2, or 4 wk after surgery. Blood pressure measured immediately before the animal was killed was significantly higher in the left femoral vein than in the sham-operated, contralateral vein. Wall thickness was increased by blood pressure elevation even at 1 wk, which restored circumferential wall stress to a control level. The stress was kept at normal up to 4 wk. Vascular tone and vascular contractility were increased by the elevation of blood pressure; however, wall elasticity and compliance were kept at a normal level. These results are very similar to those observed in hypertensive arteries, indicating that not only arteries but veins optimally operate against blood pressure elevation.

Animals↗
PubMed2002

Constant involvement of the Betz cells and pyramidal tract in amyotrophic lateral sclerosis with dementia: a clinicopathological study of eight autopsy cases.

We investigated clinicopathologically pyramidal signs, including hyperreflexia, Babinski sign, and spasticity, and the involvement of the primary motor cortex and pyramidal tract, in eight Japanese autopsy cases of amyotrophic lateral sclerosis (ALS) with dementia. Pyramidal signs were observed in seven (88%) of the eight autopsy cases. Hyperreflexia and Babinski sign were evident in seven (88%) and three (38%) patients, respectively, but spasticity was not observed in any of the eight patients. Loss of Betz cells in the primary motor cortex was evident in the seven cases in which this structure was examined. Astrocytosis in the fifth layer of the primary motor cortex was noticed in three cases. In all eight cases, involvement of the pyramidal tract was obvious in the medulla oblongata, but no involvement of the pyramidal tract was found in the midbrain. Involvement of the pyramidal tract in the spinal cord, particularly of large myelinated fibers, was observed in all six cases in which the spinal cord was examined. In ALS with dementia, pyramidal signs were shown to be present more frequently than previously believed, and the clinicopathological correlation between pyramidal signs and involvement of the pyramidal tract was obvious. Constant involvement of Betz cells and the pyramidal tract in ALS with dementia has not been reported. Our clinicopathological findings may make a contribution to the understanding of the clinicopathological hallmarks of this disorder. Furthermore, we believe that this study will also contribute to the elucidation of the nosological status of ALS with dementia.

Adult↗
PubMed2002

Classification and examination of halitosis.

In this paper, the classification of halitosis and the examination procedures used in diagnosing halitosis are outlined. Halitosis is classified into categories of genuine halitosis, pseudo-halitosis and halitophobia. Genuine halitosis is subclassified into physiologic halitosis and pathologic halitosis. Pathologic halitosis itself is subdivided into oral and extraoral halitosis. Patients diagnosed with pseudo-halitosis and halitophobia usually complain about having oral malodour that does not really exist. Pseudohalitosis can be treated by dental practitioners, but halitophobic patients must be referred to psychological specialists. Oral malodour can be measured using an organoleptic measurement or a gas chromatography analysis. The organoleptic measurement is the most practical procedure with which one can evaluate oral malodour. Gas chromatography (GC) analysis using a flame photometric detector has been shown to be the gold standard for measuring oral malodour, owing its reputation to its objectivity and reproducibility. Moreover, GC is specific for volatile sulphur compounds (VSC), which are the main causes of oral malodour. It has been demonstrated that there is a high correlation between the intensity of oral malodour and the VSC concentration as measured by GC.

Chromatography, Gas↗
PubMed2002

Treatment needs (TN) and practical remedies for halitosis.

Dental practitioners have traditionally neglected halitosis despite its high priority for the public, but practitioners' interest in halitosis has recently increased. Although oral pathologic or physiologic halitosis is easily reduced by a suitable treatment based on the treatment needs, systemic and psychological conditions sometimes confuse practitioners. Since a halitophobic patient never agrees with the result that his/her oral malodour has been reduced or eliminated after treatment, this may cause a dilemma for practitioners. Generally, halitosis patients, even genuine ones, have different psychological characteristics concerning their own breath than other individuals. Adverse psychological aspects of these patients are often promoted by the practitioner's mismanagement. Treatment Needs (TN) were, therefore, established to prevent practitioners' mismanagement of halitosis patients. By following these TN, patients can receive proper treatments for halitosis. However, to choose proper treatment measures, practitioners must refer to articles published in peer-reviewed journals, then use critical thinking to judge whether a product is effective in reducing oral malodour. Although it is challenging for dental practitioners to deal with patients with psychological conditions such as pseudo-halitosis or halitophobia, if appropriate treatments are administered accurately the practitioner does not risk mismanagement.

Attitude to Health↗
PubMed2002

Tongue brushing and mouth rinsing as basic treatment measures for halitosis.

Tongue brushing and mouth rinsing are basic treatment measures for halitosis, and as such are categorised as treatment needs (TN)-1. Although TN-1 is used for treatment of physiologic halitosis treatment, pseudo-, extra oral pathologic or halitophobic patients must also be managed with TN-1 as well as other treatments. Since the origin of physiological halitosis is mainly the dorso-posterior region of the tongue, tongue cleaning is more effective than mouth rinsing. However, practitioners should always instruct their patients on how to brush their tongues to prevent harmful effects. Another approach using a chlorhexidine mouthwash is most effective in reducing oral malodour. However, chlorhexidine should not be used routinely; therefore, zinc-containing mouthwashes have been recommended for use. People can also use chewing gum to reduce oral malodour. Surprisingly, however, it has been noted that sugarless chewing gum increased methyl mercaptan, one of the principal components of oral malodour. Mint did not reduce the concentration of methyl mercaptan either, although these products are widely used for their ability to mask oral malodour. There is a need for the development of a novel food or chewing gum that could considerably reduce VSC levels in mouth air to complement TN-1.

Anti-Infective Agents, Local↗
PubMed2002

Ex vivo expansion of human UC blood primitive hematopoietic progenitors and transplantable stem cells using human primary BM stromal cells and human AB serum.

BACKGROUND: In vitro maintenance and expansion of human hematopoietic stem cells is crucial for many clinical applications, and investigators have been using xenogeneic, especially murine, stromal cells for stem-cell expansion. In addition, many such culture systems utilize FCS-containing medium or serum-free medium that contains human- or animal-derived proteins. However, the possible transmission of infectious diseases has led to a debate about the safety of the delivery of grafts expanded in culture using cells and proteins of allogeneic or xenogeneic origin. Using primary human BM stromal cells, we have established an AB serum-based co-culture system to expand human primitive progenitors and transplantable stem cells. METHODS: Cord blood CD34+ cells were cultured on a monolayer of human BM-derived primary stromal cells with thrombopoietin (TPO), stem-cell factor (SCF) and flt3/flk2 ligand (FL) in the presence of either FCS or AB serum. One to three weeks later, cells were examined for total cells, CD34+ cells, CD34+ CD38- cells, and clonogenic progenitors. SCID mouse reconstituting cell (SRC) activity was also studied. RESULTS: Three weeks of culture with TPO, SCF, and FL supported more than a 250-fold expansion of CD34+ cells, CD34+ CD38- cells and CFU-C, regardless of the kind of serum used. SRC assay revealed that transplantable stem cells were moderately expanded as well. DISCUSSION: This ex vivo expansion system should prove valuable in clinical settings in which stromal cells and serum are available from recipients or stem-cell donors.

ADP-ribosyl Cyclase↗
PubMed2001

Expression of glial cell line-derived neurotrophic factor induced by transient forebrain ischemia in rats.

This study examined the expression of glial cell line-derived neurotrophic factor (GDNF) mRNA and the cellular localization of GDNF production in rats subjected to transient forebrain ischemia induced by four-vessel occlusion. Transient forebrain ischemia induced GDNF mRNA expression in the hippocampus from 3 h to 3 days after the ischemic episode, with peak expression at 6 h. The GDNF mRNA increase in the cerebral cortex was similar to that in the hippocampus, whereas no increase in GDNF mRNA was observed in the striatum and brainstem. Western blot analysis showed that GDNF in the hippocampal CA1 region was increased slightly from 3 to 24 h after the ischemia, and then subsequently declined to below the baseline level. In the hippocampus, GDNF was evenly produced in pyramidal neurons of both sham-operated rats and normal rats, as determined by immunohistochemistry. Interestingly, we found that ischemia-induced reactive astrocytes, as well as surviving neurons, produced GDNF in 3-7 days after the ischemia. On the other hand, in other regions, such as the cerebral cortex, striatum, and brainstem, there was no change in GDNF-positive cells secondary to ischemia. These findings suggest that expression of GDNF mRNA is regulated in part via ischemia-induced neuronal degeneration. They also suggest that ischemia-induced reactive astrocytes may produce GDNF to protect against neuronal death. Therefore, GDNF may play an important role in ischemia-induced neuronal death in the brain.

Animals↗
PubMed2001

Low M(r) protein tyrosine phosphatase inhibits growth and migration of vascular smooth muscle cells induced by platelet-derived growth factor.

Vascular smooth muscle cell (VSMC) migration and growth are positively regulated by protein tyrosine phosphorylation. Therefore, a dephosphorylation process controlled by protein tyrosine phosphatases (PTPs) must also be critical. The present study identified six cytoplasmic PTPs expressed in VSMCs: low M(r) protein tyrosine phosphatase (LMW-PTP), SHP-2, PTP36, PTP2, PTP1B, and FAP1. We further examined the functions of LMW-PTP in VSMCs using the adenovirus-mediated gene transfer of recombinant LMW-PTP. PDGF-induced activation of p38, but not of ERK MAP kinase, was blocked by LMW-PTP. LMW-PTP as well as the p38 inhibitor SB203580 inhibited DNA synthesis and cell migration upon PDGF stimulation. LMW-PTP dephosphorylated activated PDGF receptors in NIH3T3 cells, but not in VSMCs. Thus, LMW-PTP negatively regulates PDGF functions by inhibiting the p38 pathway in VSMCs although its substrate is unclear. These findings strongly demonstrate that PTPs are important as negative regulators for VSMC growth and migration, processes that are closely related to the progression of atherosclerosis.

3T3 Cells↗
PubMed2001

MAPK and Akt act cooperatively but independently on hypoxia inducible factor-1alpha in rasV12 upregulation of VEGF.

Oncogenic ras upregulates the expression of VEGF through the activation of the transcriptional enhancer hypoxia inducible factor-1alpha (HIF-1alpha) by a still poorly understood mechanism. Here, we demonstrate that both the Raf/MEK/MAPK and the PI3 kinase/Akt signaling pathways potently and additively stimulate the expression from a hypoxia response element (HRE) within the 5'flanking region of the VEGF promoter. Interestingly, while MAPK appears to specifically upregulate the transactivation activity of HIF-1alpha through direct phosphorylation of its regulatory/inhibitory domain, GSK-3, a downstream target of Akt, directly phosphorylates the HIF-1alpha oxygen-dependent degradation domain. These results suggest a novel mechanism whereby two divergent signaling pathways emerging from Ras may cooperatively but independently regulate the activity of a HIF-1alpha, thereby promoting the expression of a potent angiogenic mediator.

3T3 Cells↗
PubMed2001

Gene transfer of dominant-negative mutants of extracellular signal-regulated kinase and c-Jun NH2-terminal kinase prevents neointimal formation in balloon-injured rat artery.

We previously reported that extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK), belonging to mitogen-activated protein kinases, are rapidly activated in balloon-injured artery. Therefore, we examined the role of these kinase activations in neointimal formation by using an in vivo gene transfer technique. We made the dominant-negative mutants of ERK (DN-ERK) and JNK (DN-JNK) to specifically inhibit endogenous ERK and JNK activation, respectively. Before balloon injury, these mutants were transfected into rat carotid artery using the hemagglutinating virus of Japan liposome method. In vivo transfection of DN-ERK and DN-JNK significantly suppressed the activation of ERK and JNK, respectively, after balloon injury, confirming successful expression of the transfected genes. Neointimal formation at 14 and 28 days after injury was prevented by gene transfer of DN-ERK or DN-JNK. Furthermore, bromodeoxyuridine labeling index and total cell-counting analysis at 7 days showed that either DN-ERK or DN-JNK remarkably suppressed smooth muscle cell (SMC) proliferation in both the intima and the media after injury. Gene transfer of wild-type ERK (W-ERK) or JNK (W-JNK) significantly enhanced neointimal hyperplasia at 14 days after injury. Furthermore, DN-ERK and DN-JNK significantly suppressed serum-induced SMC proliferation in vitro. We obtained the first evidence that in vivo gene transfer of DN-ERK or DN-JNK prevented neointimal formation in balloon-injured artery by inhibiting SMC proliferation. Thus, ERK and JNK activation triggers SMC proliferation, leading to neointimal formation. These kinases may be the new therapeutic targets for prevention of vascular diseases.

Angioplasty, Balloon↗