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Biomedical subjects

S Nakamura

Publications and source records attributed to S Nakamura.

At least 73 records · Page 4Linked to original sources
PubMed2004

Bonding between resin luting cement and glass infiltrated alumina-reinforced ceramics with silane coupling agent.

The purpose of this study was to evaluate the shear bond strengths of three dual-cured resin luting cements (Linkmax HV, Panavia Fluoro Cement, and RelyX ARC) to glass-infiltrated alumina-reinforced ceramic material and the effect of four silane coupling agents (Clearfil Porcelain Bond, GC Ceramic Primer, Porcelain LinerM, and Tokuso Ceramic Primer) on the bond strength. The two type-shaped of In-Ceram alumina ceramic glass-infiltrated specimens were untreated or treated with one of the four ceramic primers and then cemented together with one of the three dual-cured resin luting cements. Half of the specimens were stored in water at 37 degrees C for 24 h and the other half thermocycled 20,000 times before shear bond strength testing. Surface treatment by all silane coupling agents improved the shear bond strength compared with non-treatment. The specimens treated with Clearfil Porcelain Bond showed significantly greater shear bond strength than any of the other three silane coupling agents regardless of resin luting cements and thermocycling except for the use of Panavia Fluoro Cement at 20,000 thermocycles. When the alumina-reinforced ceramic material was treated with any silane coupling agent except GC Ceramic Primer and cemented with Linkmax HV, no significant differences in bond strength were noted between after water storage and after 20,000 thermocycles. After 20,000 thermocycles, all specimens except for the combined use of Clearfil Porcelain Bond or GC Ceramic Primer and Linkmax HV and GC Ceramic Primer and Panavia Fluoro Cement showed adhesive failures at the ceramic-resin luting cement interface.

Aluminum Oxide↗
PubMed2004

A case of secondary diabetes mellitus with acromegaly improved by pioglitazone.

AIM: The acromegaly patient was diagnosed with Type 2 diabetes mellitus. His HbA1c was 10.6% and fasting blood glucose (FBG) 15.3 mmol/l. We prescribed glibenclamide (10 mg/day), but his HbA1c and FBG remained high. At this stage, treatment with short-acting insulin was instigated at a dose of 20 U/day. However, the patient's blood glucose level remained unsatisfactory. We tried using pioglitazone. METHOD: Pioglitazone was prescribed at 30 mg/day in combination with the insulin. RESULTS: The FBG and HbA1c value decreased to 7.2 mmol/l and 7.3%, respectively, within 2 months and insulin was discontinued. Pioglitazone alone was able to control the FBG level. CONCLUSIONS: Pioglitazone treatment might be considered as a choice for similar cases of diabetes secondary to acromegaly.

Acromegaly↗
PubMed2004

Significance of serum soluble thrombomodulin level in acute cerebral infarction.

The purpose of the present study was to investigate sequential changes in serum soluble thrombomodulin (sTM) concentrations in patients with acute cerebral infarction (ACI), and to correlate sTM concentrations with the severity of ACI evaluated by Japan Stroke Scale. Eighty-three consecutive patients with ACI were enrolled, and blood examinations were carried out soon after admission and 1 month after. sTM concentrations at admission in patients with cardioembolic infarction (3.2 +/- 1.2 ng/ml) were significantly lower than those of lacunar infarction (3.9 +/- 1.2) (P < 0.05). Serial examinations revealed that sTM concentrations increased significantly 1 month after admission (3.8 +/- 1.2), compared with those at admission (3.6 +/- 1.2) (P = 0.02). Of three ACI subtypes, sTM concentrations during 1 month significantly increased in atherothrombotic infarction (P = 0.002) or, not significantly, in cardioembolic infarction (P = 0.09). The sTM concentrations at admission showed a significant inverse correlation with the severity of ACI (P = 0.04). Although sTM concentrations serve as a useful marker for endothelial cell damage, they are decreased in patients with severe ACI, especially in atherothrombotic and cardioembolic infarctions. Lower sTM concentrations may play some important role in disease progression or in the recurrence following ACI, although the exact mechanism of this unique result should be clarified.

Acute Disease↗
PubMed2004

Cell death and cell proliferation in the regeneration of atrophied rat submandibular glands after duct ligation.

BACKGROUND: The present study aimed to clarify the proliferation and apoptosis of parenchymal cells during regeneration of rat submandibular glands following atrophy. METHODS: Atrophy of the right submandibular gland of rats was induced by excretory duct ligation at the hilum with metal clips, which were removed 1 week (day 0) after ligation. The right submandibular glands were collected from 0 to 14 days after removal of the clips and investigated using immunohistochemistry for proliferating cell nuclear antigen (PCNA) as a marker of proliferating cells, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) as a marker of apoptotic cells, and transmission electron microscopy (TEM). RESULTS: After 1 week of ligation, there were many remaining ducts and a few acini in the atrophic glands. At day 3 after discontinuing the ligation, newly formed acini appeared and thereafter increased in number and maturity. Many residual and newly formed acinar cells showed positive reaction to PCNA especially at days 4 and 5. The PCNA-positive duct cells decreased in number with the regeneration. A few TUNEL-positive acinar and duct cells were identified during regeneration. Mitosis and apoptosis of parenchymal cells were also identified by TEM. CONCLUSIONS: During regeneration of the submandibular gland after atrophy, both residual and newly formed acinar cells proliferate actively. There is also apoptosis of parenchymal cells; however, the significance of apoptosis is low.

Animals↗
PubMed2004

Effects of near-infrared irradiation to stellate ganglion in glossodynia.

OBJECTIVE: This study was designed to assess the effect of stellate ganglion near-infrared irradiation (SGR) on glossodynia and the mechanism of action. STUDY DESIGN: Thirty-seven patients with glossodynia received SGR once weekly for 4 weeks. The response to treatment was evaluated on the basis of the change in pain intensity, assessed with a visual analogue scale (VAS) before and after 4 weeks of treatment. The temperature and blood flow of the tongue were also measured before and after first SGR. As control, eight healthy subjects were studied. RESULTS: Tongue pain as assessed by the VAS decreased in 28 of the 37 patients (75.7%). Mean pain intensity decreased significantly from 5.1 +/- 2.2 to 1.9 +/- 2.1 (P < 0.05). Tongue blood flow at rest in the patients with glossodynia [7.2 +/- 1.6 ml min(-1) (100 g)(-1)] was significantly lower than that in the healthy subjects [7.8 +/- 0.23 ml min(-1) (100 g)(-1)]. Five minutes after SGR, the temperature of the tongue rose 1.5 +/- 0.21 degrees C, and blood flow increased to 8.5 +/- 1.2 ml min(-1) (100 g)(-1). Tongue blood flow (at rest) after 4 weeks of SGR had increased to 7.7 +/- 1.1 ml min(-1) (100 g)(-1). CONCLUSION: SGR is an effective treatment for glossodynia. The mechanism by which SGR improves symptoms associated with glossodynia is thought to be as follows: SGR inhibits abnormally increased sympathetic activity associated with glossodynia. This is followed by normalization of decreased tongue blood flow, thereby alleviating pain.

Aged↗
PubMed2003

Energetic protons from a few-micron metallic foil evaporated by an intense laser pulse.

With detailed experimental studies and hydrodynamics and particle-in-cell simulations we investigate the role of the prepulse in laser proton acceleration. The prepulse or pedestal (amplified spontaneous emission) can completely evaporate the irradiated region of a sufficiently thin foil; therefore, the main part of the laser pulse interacts with an underdense plasma. The multiparametric particle-in-cell simulations demonstrate that the main pulse generates the quasistatic magnetic field, which in its turn produces the long-lived charge separation electrostatic field, accelerating the ions.

Journal Article↗
PubMed2003

Endogenous GABA in the commissural subnucleus of the NTS inhibits the carotid chemoreceptor reflex via GABA A receptors in rats.

Using urethane-chloralose anesthetized rats, we investigated which GABA receptor is responsible for the action of endogenous GABA on the carotid chemoreceptor reflex in the commissural subnucleus of the nucleus tractus solitarius (commNTS). Microinjection of the selective GABA uptake inhibitor nipecotic acid (40 nmol) into the commNTS attenuated the increases in respiration (respiratory movement and rate) and the elevation in arterial blood pressure elicited by carotid chemoreceptor stimulation. These effects were completely antagonized by premicroinjection of the GABA(A) antagonist bicuculline (20 pmol), but not of the GABA(B) antagonist 2-OH-saclofen (400 pmol), into the same site. These findings suggest that endogenous GABA mainly acts on GABA(A) receptors, and inhibits the chemoreceptor reflex in the commNTS in rats.

Animals↗
PubMed2003

Endogenous retrovirus HC2 pol fragments in the squirrel monkey: expression, evolution, and phylogeny.

Human endogenous retrovirus HC2 is an incomplete provirus containing the entire gag and pol genes and a 3' LTR, whereas the 5' LTR and env gene are missing. We investigated expression of the HC2 pol gene in the squirrel monkey ( Saimiri sciureus) by RT-PCR. The pol gene was expressed in cerebellum, liver, lung, and spleen of the squirrel monkey, but not in six other tissues tested. RT-PCR products were cloned and sequenced resulting in seven sequences that were analyzed. These sequences showed 73.7-89.2% sequence similarity to HC2 pol genes present in the human genome. No frameshifts or termination codons caused by deletion/insertion or point mutation were found in clones SM-HC27-1 and SM-HC27-4 isolated from squirrel monkey lung tissues. Phylogenetic analysis showed that HC2 pol elements from the squirrel monkey were randomly clustered with those in human genome and the genomes of other nonhuman primates, indicating that substantial evolution of the HC2 elements occurred prior to primate speciation with additional evolution of the elements, independent of each other, after speciation.

Amino Acid Sequence↗
PubMed2003

Strict paternal transmission of mitochondrial DNA of Chlamydomonas species is explained by selection against maternal nucleoids.

The non-Mendelian inheritance of organelle DNA is common in most plants and animals. Here we examined inheritance mechanisms involved in the transfer of mitochondrial DNA. We successively backcrossed (to F(5)) two interfertile strains of the unicellular isogamous haploid algae Chlamydomonas reinhardtii and Chlamydomonas smithii to match nuclear backgrounds and examine transmission patterns of mitochondrial DNA by PCR analysis of cob gene sequences. Mitochondrial DNA was strictly transmitted paternally. To investigate the behavior of parental mitochondrial DNA, we used F(5) progeny to form zygotes and isolated single zygotes. The results showed selective disappearance of maternal mitochondrial nucleoids occurred between 3 and 6 h after zygote formation.

Animals↗
PubMed2003

Materno-fetal coordination of stress-induced Fos expression in the hypothalamic paraventricular nucleus during pregnancy.

This study investigates whether maternal stress during pregnancy induces maternal and fetal hypothalamic paraventricular nucleus (PVN) neuronal activation and the effects of maternal stress on fetal hypothalamic and PVN brain-derived neurotrophic factor (BDNF) expression. Pregnant rats were exposed to three types of maternal stress with varying severity (restraint, forced walking and immobilization) for 30 min on gestational day 21. Severity of stress was assessed by measurement of maternal plasma corticosterone 30 min following the stimulus. Maternal plasma corticosterone increased in each stress response group (immobilization>forced walking>restraint). Further, the expression of Fos protein, a marker of neuronal activation, increased in the fetal and maternal PVN in direct relation to the severity of stress treatments. Forced walking and immobilized stress, but not restraint stress, significantly increased BDNF expression in the fetal hypothalamus.These findings suggest that the fetal hypothalamic-pituitary-adrenal (HPA) response following maternal stress mirrors maternal HPA activation. In addition, BDNF may play a role in protecting fetal brain neurons from damage caused by severe stress.

Animals↗
PubMed2003

Follicular dendritic cell tumor in the oro-pharyngeal region: report of a case and a review of the literature.

A case of follicular dendritic cell tumor (FDC tumor) arised in the aro-pharyngeal region is reported in a 16-year-old Japanese boy. He had a swelling in the right retromolar trigone and soft palate. Clinical examination disclosed a 25 mm x 30 mm, elastic hard, ulcerated mass. CT scans showed a low density lesion in the right medial parapharyngeal area. The biopsy specimen revealed a low-grade malignant tumor. The patient underwent a tumorectomy which was extended to include the adjacent palatine tonsil. The tumor cells, with a clear cytoplasm and oval nucleus, were immunoreactive for S-100 (N/A), CD 21 (1F8), fascin (55K-2) and FDC (CNA42). The fascicular sheet pattern arrangement of the tumor cells was partly characteristic. The final diagnosis was an follicular dendritic cell tumor. Three courses of adjuvant chemoradiotherapy were administered postoperatively. Clinical features, pathological diagnosis and immunohistochemical markers for distinguishing FDC tumor are reviewed.

Adolescent↗
PubMed2003

Accumulation of oligoclonal T cells in the infiltrating lymphocytes in oral lichen planus.

BACKGROUND: Identification of a disease-specific and possibly pathogenic T-cell receptor (TCR) in oral lichen planus (OLP) is one of the most important steps to reveal the pathogenic antigen recognized by the T cells and thereby elucidate the pathogenesis and etiology of OLP. METHODS: In buccal mucosa biopsy specimens and peripheral blood mononuclear cells (PBMC) from seven patients with OLP, the TCR V beta gene usage was examined by polymerase chain reaction-based and single-strand conformation polymorphism analyses. RESULTS: The V beta families expressed in the biopsy specimens were markedly heterogeneous, but they were restricted in comparison to those observed in the PBMC. The V beta families predominantly expressed in the biopsy specimens in comparison with the PBMC were still heterogeneous in individual patients and differed from patient to patient; however, V beta 2, V beta 6, and V beta 19 were commonly predominant in the biopsy specimens from more than half of the patients. Among the V beta families predominantly expressed in the biopsy specimens, the accumulation of T-cell clonotypes was observed in the majority of the V beta families including V beta 6 and V beta 19; however, it was not observed in the minority of the V beta families including V beta 2. CONCLUSIONS: These results suggest that unique T-cell populations bearing V beta 2, V beta 6, or V beta 19 gene products tend to expand in OLP lesions as a consequence of in situ stimulation with a restricted epitope of either a nominal antigen on the MHC molecule for the majority of the V beta families, even if only in minor populations, or of a common superantigen for the minority of the V beta families.

Aged↗
PubMed2003

Characterization of the development of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells during osteoinduction by rhBMP-2: a histochemical and ultrastructural study.

OBJECTIVE: To investigate the characteristics of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells induced by recombinant human bone morphogenetic protein-2 (rhBMP-2). MATERIALS AND METHODS: rhBMP-2 (5 microg) combined with atelocollagen was implanted into calf muscles of rats and removed on days 7, 10, 14, 21, or 28. Tissue sections were examined using: (i) hematoxylin/Alcian blue/Sirius red stain, (ii) enzyme histochemistry for alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase activity, (iii) immunohistochemistry for types I, II, and X collagen, and (iv) electron microscopy. RESULTS: On day 7, numerous fibroblast-like cells with ALP activity were present on the pellet rim. On day 10, chondroid matrix (CM) had formed, contained both type I collagen and proteoglycans, and often continued into the BMP pellet. On day 14, bone-like matrix formed around hypertrophic chondrocytes simultaneously with endochondral ossification. Coexpression of types I and II collagen within chondrocytes and osteocytes was observed throughout the time course of the experiment. CONCLUSION: These results suggest that fibroblast-like cells invading the pellet differentiate into chondrocytes and form CM under the scaffold of the carrier component. It appears that some chondrocytes change their phenotype to produce the bone-like matrix and remain within the endochondral bone. This process enables rapid osteogenesis to occur.

Acid Phosphatase↗
PubMed2003

Comparison of digestibility and breath hydrogen gas excretion of fructo-oligosaccharide, galactosyl-sucrose, and isomalto-oligosaccharide in healthy human subjects.

OBJECTIVES: To clarify the difference of digestibility in the small intestine among fructo-oligosaccharide (FOS), galactosyl-sucrose (GS), and isomalto-oligosaccharide (IMO) using breath hydrogen test. DESIGN: The first step: screening test of breath hydrogen excretion and FOS tolerance test to select the subjects. The second step: breath hydrogen test of three kinds of oligosaccharides, carried out using precautionary regulations. The ingestion order was 10 g of FOS, GS, and IMO, with increases, at 1-week interval, up to 20 g, respectively. Breath gas was collected before, at 20 min intervals from 40 to 120 min after, and at 30 min intervals from 120 min to 7 h after ingestion of test substance. SETTING: Laboratory of Public Health Nutrition, Department of Nutrition and Health Sciences, Siebold University of Nagasaki, Nagasaki, Japan. SUBJECTS: A total of nine males (average: age 25.7+/-3.5 y, weight 61.9+/-8.8 kg, height 170.0+/-6.0 cm) and 29 females (average: 23.1+/-7.2 y, 52.9+/-5.3 kg, 157.5+/-5.1 cm) from the University of Tokyo and Siebold University of Nagasaki. MAIN OUTCOME MEASURES: Breath hydrogen excretion from end-expiratory gas. RESULT: : Breath hydrogen of FOS was more remarkably excreted than that of GS; that of IMO was slight; and that of AUC (10 g) was significantly different. FOS was 9768+/-3253 ppm, GS was 3662+/-2632 ppm, and IMO was 831+/-1154 ppm. A dose dependence was observed at doses between 10 and 20 g of FOS and GS, and the initial time of 20 g was earlier than that of 10 g. CONCLUSIONS: FOS was not hydrolyzed, GS was slightly hydrolyzed, and IMO was readily hydrolyzed by small intestinal enzymes. H(2) gas reflected fermentability in the large intestine. SPONSORSHIP: Siebold University of Nagasaki.

Adult↗