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Biomedical subjects

H Ohno

Publications and source records attributed to H Ohno.

At least 37 records · Page 2Linked to original sources
PubMed2003

Degradation of resin-dentin bonds using NaOCl storage.

OBJECTIVE: Several recent studies have reported collagen hydrolysis within bonds over the long-term. This may be one reason for the degradation of the bonds. This study therefore aimed to determine the effects of NaOCl on adhesive system bonds (total-etch bonding system vs. self-etching primer system) to dentin in order to accelerate the durability testing. METHODS: Resin-dentin bonded specimens were produced using Liner Bond 2V (Kuraray), a self-etching primer system, and OptiBond SOLO (Kerr), a total-etch bonding system, according to the manufacturers' instructions. The bonded specimens were serially sectioned in both x and y directions across the adhesive interface to obtain beams (adhesive area: 0.9 mm(2)). The specimens were immersed in 10% NaOCl solution for 1-5h after being stored in water at 37 degrees C for 24h. Control specimens were tested without exposure to NaOCl. After storage, micro-tensile bond tests were performed. Results were analyzed by two-way ANOVA and Fisher's PLSD tests (p<0.05). All fractured surfaces were observed by SEM, and examined using an image analyzer. RESULTS: The bond strengths decreased with increasing storage time in NaOCl. Fractography showed that NaOCl had a greater effect on the bond structure of OptiBond SOLO than on that of Liner Bond 2V, although both adhesives were susceptible. SIGNIFICANCE: Deterioration of the bonds was responsible for the effect of NaOCl on the hybrid layer. This deterioration may occur in humans in cases of deproteinization within the bonds.

Acid Etching, Dental↗
PubMed2003

Genetic variation in hypoxia-inducible factor 1alpha and its possible association with high altitude adaptation in Sherpas.

Hypoxic stress at high altitude requires adaptations in several physiological functions to ensure the optimal oxygenation of all cells. Several lines of evidence suggested that high-altitude native populations such as Sherpas have been genetically adapted to their stressful environment. We investigated the genetic variation in the hypoxia-inducible factor (HIF)-1alpha gene in Sherpas as compared with Japanese, native lowlanders, and found a novel dinucleotide repeat polymorphism in intron 13 of the HIF-1alpha gene. GT15 allele was more frequent in Japanese than in Sherpas with statistical significance, while GT14 allele was significantly more frequent in Sherpas as compared with Japanese. A possible genetic variation in the HIF-1alpha gene might function in adaptation to living at high altitude. Because the activity of HIF-1 is regulated by multiple steps including the transcriptional level, the effect of the polymorphism in intron 13 on the cellular hypoxic responses remains to be elucidated.

Adaptation, Physiological↗
PubMed2003

Clinical longevity of resin-bonded bridges bonded using a vinyl-thiol primer.

The purpose of this study is to clinically confirm the adhesive effect of a vinyl-thiol primer (V-Primer) for precious alloys. Further, we examined the failure of resin-bonded bridges (RBBs) in order to improve the clinical longevity of RBBs, and to analyse the causes of failure. Twenty-six RBBs were bonded with V-primer and Super Bond C & B between May 1987 and December 1997 in the Dental Clinic of the Health Sciences University of Hokkaido. The RBBs were made of silver-palladium-gold alloy or metal-ceramic gold alloys. V-primer was effective in bonding Super Bond C & B to the RBBs made of silver-palladium-gold alloys. Ten prostheses had functioned satisfactorily for 8-11 years. However, six of the 26 RBBs had become detached. In four of the six failed RBBs, the type of bond failure was a mixture fracture in the resin-enamel interface. Our results suggest that: (1) V-primer is effective on RBBs made of silver-palladium-gold alloys. (2) Mechanical retention is necessary for retainers to improve the longevity of RBBs when the V-primer is applied to RBBs made of precious alloys without copper. (3) The RBB should not be applied to abutment teeth that have differences in tooth mobility.

Adhesives↗
PubMed2003

Intermittent hypobaric hypoxia increases the ability of neutrophils to generate superoxide anion in humans.

1. We investigated the effect of intermittent exposure to hypobaric hypoxia on the ability of neutrophils to generate.O2-. 2. Seven male volunteers were exposed intermittently to hypobaric hypoxia, equivalent to an altitude of 4500 m, for 7 successive days. Peripheral blood samples were collected before and after the 2 h course of hypobaric hypoxia on days 1 and 7 and neutrophils were subjected to a chemiluminescence assay for.O2- production. 3. On day 1, 2 h exposure to hypobaric hypoxia induced granulocytosis (P < 0.01), but the ability of neutrophils to generate.O2- was unchanged. 4. On day 7, such granulocytosis was not observed, suggesting acclimatization to hypobaric hypoxia. 5. The ability of neutrophils to generate.O2- was significantly increased on day 7 (P < 0.01), although there was no definite change in the mRNA expression of NADPH oxidase subunits in the cells. 6. The results suggest that the ability of neutrophils to generate.O2- may be gradually potentiated by intermittent exposure to hypobaric hypoxia, even after the number of neutrophils in peripheral blood stabilizes.

Adult↗
PubMed2003

[Natural evolution of coronary artery ectasia after coronary artery bypass grafting].

Coronary artery aneurysm and ectasia, unusual angiographic findings, are considered as variant of atherosclerotic coronary artery disease. A 49-year-old man whose right coronary artery ectasia had progressed to large aneurysm, accompanied by advanced obstructive coronary artery disease, 6 years after the initial coronary artery bypass grafting. It was treated with ligation of aneurysm and distal bypass grafting under cardiopulmonary bypass. Fragile fresh clot was formed within the aneurysm irrespective of coumadin therapy as a standard regimen for the coronary artery ectasias. We will discuss the surgical management for the dilated coronary artery with significant coronary stenosis.

Coronary Aneurysm↗
PubMed2002

Fractured surface characterization: wet versus dry bonding.

OBJECTIVE: Fractographic analysis was conducted to evaluate the resin-dentin bond structures made under wet and dry conditions. METHODS: Resin-dentin bonded specimens were prepared using two adhesive resin systems (Single Bond/SB; 3M and All Bond 2/AB2; Bisco Inc) under wet and dry conditions. The specimens were sectioned perpendicular to the adhesive interface to produce a square bar-shaped specimen (adhesive area: 0.9 mm(2)) by means of a diamond saw. The mean bond tensile test was then conducted at a crosshead speed of 1.0 mm/min. The mean bond strengths were statistically compared with two-way ANOVA and Fisher's PLSD test (p<0.05). Subsequently, the fractured surfaces of all specimens were examined using SEM and the area fractions of failure modes (%) were measured using an image analyzer on SEM microphotographs. RESULTS: No significant differences in tensile-bond strength were observed between SB (60.1+/-16.4MPa) and AB2 (69.8+/-17.4MPa) (p>0.05) under wet conditions. However, the bond strength either of SB or AB2 made under wet conditions was significantly greater than those made under dry conditions (SB: 26.2+/-12.5MPa and AB2: 6.8+/-3.3MPa) (p<0.05). Under fractographic analysis, the major portion at the fractured surface was occupied by the cohesive failure of bonding resin and the resin composite for the wet conditions, and the top of the hybrid layer for the dry conditions in both systems. SIGNIFICANCE: The interaction between the top of the hybrid layer and the bonding resin influenced the bond integrity.

Adhesiveness↗
PubMed2002

Mechanical behavior at different temperatures and stresses for superelastic nickel-titanium orthodontic wires having different transformation temperatures.

OBJECTIVE: The purpose of this study was to investigate the mechanical properties of superelastic nickel-titanium orthodontic wires under controlled stress and temperature. METHODS: Three different superelastic nickel-titanium wires were examined using differential scanning calorimetry (DSC), three-point bending test and micro X-ray diffraction (micro-XRD). The three-point bending test was carried out at constant temperature (23, 37 and 60 degrees C) and stepwise temperature changes (37-60 degrees C and to 37 degrees C) (37-2 degrees C and to 37 degrees C). Five specimens of each wire were tested. Micro-XRD spectra were measured at the tension side of the wire when the temperature changed from 37 to 60 degrees C or 2 degrees C. RESULTS: The load during the stepwise temperature changes (37-2 degrees C and to 37 degrees C) was consistent with that measured at a corresponding constant temperature. The micro XRD spectrum clearly showed that the austenite phase was transformed to martensite phase when the temperature is decreased from 37 to 2 degrees C. In a stepwise temperature change (37-60 degrees C and to 37 degrees C), the load became higher than the original load at each corresponding constant temperature. However, there was no detectable change in the micro-XRD spectrum when the temperature was increased from 37 to 60 degrees C. SIGNIFICANCE: The superelastic nickel-titanium wires exhibited complicated and unexpected mechanical properties under stepwise temperature change. This study shows the possibility of qualitative analysis using micro-XRD to understand mechanical properties of these nickel-titanium wires.

Calorimetry, Differential Scanning↗
PubMed2002

Micro X-ray diffraction study of superelastic nickel-titanium orthodontic wires at different temperatures and stresses.

The phase transformation behavior in three commercial nickel-titanium orthodontic wires having different transformation temperatures was studied by micro X-ray diffraction (micro-XRD). Micro-XRD spectra were obtained at three different included bending angles (135 degrees, 146 degrees and 157 degrees) and three different temperatures (25 degrees C, 37 degrees C and 60 degrees C). The regions analyzed by micro-XRD were within the separate areas of a given wire specimen that experienced only tensile or compressive strain. The intensity ratio (M002/A110) between the 002 peak for martensitic NiTi and the 110 peak for austenitic NiTi was employed as the index to the proportions of the martensite and austenite phases. The ratio of martensite to austenite increased in all three nickel-titanium wires with decreasing included bending angle (greater permanent bending deformation), and was lower within the compression area for all wires at all bending angles than within the tension area. Micro-XRD provides an effective method for quantitative evaluation of the proportions of these two phases in nickel-titanium orthodontic wires, even though considerable preferred crystallographic orientation exists because of the wire drawing process.

Alloys↗
PubMed2002

Bcl-3/IgH translocation (14;19)(q32;q13) in non-Hodgkin's lymphomas.

The recurrent cytogenetic (CG) abnormality t(14;19)(q32;q13) involving the oncogene BCL3 is described in patients with atypical chronic lymphocytic leukemia (CLL). We report four patients with non-Hodgkin's lymphoma (NHL) bearing t(14;19). All cases were female and their age ranged from 62 to 91. Histologically, there were two cases of small lymphocytic lymphoma (SLL), both CD11c positive with atypical morphology, one case of Burkitt like lymphoma (BLL), and one case of diffuse large cell lymphoma (DLC-L). One SLL patient showed t(14;19) as the sole abnormality and experienced a benign course for 8 years. The other three cases showed secondary CG progression, including tetraploidy, del(6q), t(8;22) and del(13q). These cases were aggressive in clinical behavior, including an SLL case which transformed to DLC lymphoma in 4 months. Southern analysis and long distance PCR confirmed BCL3/IgH Calpha translocation in one case. We propose that NHLs with t(14;19) may have evolved from the same spectrum of disease as atypical CLL. The poor prognosis of t(14;19) disease is associated with the occurrence of recurrent secondary CG changes, commonly found in B cell lymphoproliferative diseases.

Aged↗
PubMed2002

The extent to which resin can infiltrate dentin by acetone-based adhesives.

The combined methodologies of fractography and laser-Raman spectroscopic analysis were used for evaluation of the resin-dentin bonds made with wet and dry bonding. Resin-dentin-bonded beams were produced by means of 2 acetone-based adhesives (One-Step and Prime & Bond NT). The micro-tensile bond test was conducted, and the fractured surfaces of all specimens were examined by SEM and an image analyzer. The amount of resin infiltration within the hybrid layer was quantified by means of a laser-Raman spectroscope. In Raman analysis, the amount of resin impregnation within the hybrid layer of the dry bonding was found to be significantly lower (approximately 50%) than that in the wet one. Under fractographic analysis, a correlation was found between the bond strength and the failure mode. Based on those findings, it was suggested that the integrity between the bonding resin and the top of the hybrid layer played a major role in bond strength.

Acetone↗
PubMed2002

Washing of the residual solution of cardiopulmonary bypass circuit after coronary artery bypass grafting in idiopathic thrombocytopenic purpura.

A 76-year-old female with chronic idiopathic thrombocytopenic purpura required coronary bypass grafting. Preoperative treatment with high-dose intravenous immunoglobulin at a dose of 0.4 g/kg/day raised the platelet count from 57,000 to 110,000/microL. After termination of cardiopulmonary bypass (CPB) the residual blood in the CPB circuit was washed to reduce total immunoglobulin G (IgG) level, including platelet-associated immunoglobulin G (PA-IgG), and returned to the patient. Intraoperative platelet transfusion was used due to a drop in platelet count to the pretreatment level. The postoperative level of IgG and PA-IgG remained significantly lower than preoperatively. The postoperative course was uneventful and without bleeding complications. Perioperative management of a patient with idiopathic thrombocytopenic purpura undergoing open-heart surgery is discussed.

Aged↗
PubMed2001

Cytoplasmic tail-dependent internalization of membrane-type 1 matrix metalloproteinase is important for its invasion-promoting activity.

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane proteinase that degrades the pericellular extracellular matrix (ECM) and is expressed in many migratory cells, including invasive cancer cells. MT1-MMP has been shown to localize at the migration edge and to promote cell migration; however, it is not clear how the enzyme is regulated during the migration process. Here, we report that MT1-MMP is internalized from the surface and that this event depends on the sequence of its cytoplasmic tail. Di-leucine (Leu571-572 and Leu578-579) and tyrosine573 residues are important for the internalization, and the mu2 subunit of adaptor protein 2, a component of clathrin-coated pits for membrane protein internalization, was found to bind to the LLY573 sequence. MT1-MMP was internalized predominantly at the adherent edge and was found to colocalize with clathrin-coated vesicles. The mutations that disturb internalization caused accumulation of the enzyme at the adherent edge, though the net proteolytic activity was not affected much. Interestingly, whereas expression of MT1-MMP enhances cell migration and invasion, the internalization-defective mutants failed to promote either activity. These data indicate that dynamic turnover of MT1-MMP at the migration edge by internalization is important for proper enzyme function during cell migration and invasion.

Animals↗
PubMed2001

Negative regulation of LPS-stimulated expression of inducible nitric oxide synthase by AP-1 in macrophage cell line J774A.1.

The level of NOS II mRNA was markedly increased during 24 h lipopolysaccharide (LPS) stimulation, but showed no further increase thereafter. On the other hand, the level of NOS II mRNA in J774A.1 cells transfected with an expression vector containing the rat csk cDNA (J.Csk) was significantly increased during 3 h LPS stimulation, but rather decreased thereafter. Although no significant difference was observed in the activation of NF-kappaB by LPS among parental J774A.1, J774A.1 transfected with promoterless vector (J.pBK), and J.Csk cells, activity of c-Jun N-terminal kinase (JNK) and nuclear translocation of nuclear factor activator protein-1 (AP-1) were markedly upregulated in the J.Csk cells. Then luciferase reporter vectors containing NOS II promoter with mutations in two AP-1-like sites (U site, -1126 approximately -1120; L site, -524 approximately -518) were transiently transfected in J774A.1 cells. The promoter activity following LPS stimulation for 24 h was significantly increased by mutation at the L site, but not by mutation at the U site, suggesting that NOS II expression is negatively regulated, at least in part, through the AP-1-like L site in response to LPS.

Animals↗
PubMed2001

Correlation of peripheral blood OX40+(CD134+) T cells with chronic graft-versus-host disease in patients who underwent allogeneic hematopoietic stem cell transplantation.

There is no reliable laboratory indicator of the onset of chronic graft-versus-host disease (cGVHD). This study looks at whether the expression of OX40, a member of the tumor necrosis factor receptor family, is related to the development of cGVHD in patients who underwent allogeneic hematopoietic stem cell transplantation. Peripheral blood mononuclear cells from 22 patients after day 100 were subjected to multicolor flow cytometry. The percentages of both OX40+CD4+ and OX40+CD8+ T cells were significantly higher in patients with cGVHD than those without (P <.0001 and P =.001, respectively). Serial analyses showed that OX40+CD4+ T cells elevated before the onset of cGVHD and closely correlated with the therapeutic response. The expression of CD25, CD69, and HLA-DR was partially detectable on OX40+ T cells. These results indicate that serial measurement of OX40+ T cells is useful for predicting the onset as well as the therapeutic response of cGVHD and raise a possibility that the OX40/gp34 system is involved in the pathogenesis of cGVHD.

Anemia, Aplastic↗
PubMed2001

Total synthesis of (+/-)-stemodinone via an efficient ring-exchange strategy.

A total synthesis of (+/-)-stemodinone, a tetracyclic stemodane diterpene, from the known tricyclic methyl olefin 11 is described. The key steps involve an efficient ring-exchange reaction and palladium(0)-catalyzed lactone migration. The ring-exchange strategy for controlling the stereochemistry was based on an initial Diels-Alder reaction to form a new ring followed by cleavage of the original ring. Cleavage of the original ring of the Diels-Alder adduct 9 was achieved by an initial regio- and chemoselective Baeyer-Villiger oxidation followed by the Pd(0)-catalyzed lactone-migration reaction reported by us.

Antiviral Agents↗
PubMed2001

The neuronal form of adaptor protein-3 is required for synaptic vesicle formation from endosomes.

Heterotetrameric adaptor complexes vesiculate donor membranes. One of the adaptor protein complexes, AP-3, is present in two forms; one form is expressed in all tissues of the body, whereas the other is restricted to brain. Mice lacking both the ubiquitous and neuronal forms of AP-3 exhibit neurological disorders that are not observed in mice that are mutant only in the ubiquitous form. To begin to understand the role of neuronal AP-3 in neurological disease, we investigated its function in in vitro assays as well as its localization in neural tissue. In the presence of GTPgammaS both ubiquitous and neuronal forms of AP-3 can bind to purified synaptic vesicles. However, only the neuronal form of AP-3 can produce synaptic vesicles from endosomes in vitro. We also identified that the expression of neuronal AP-3 is limited to varicosities of neuronal-like processes and is expressed in most axons of the brain. Although the AP-2/clathrin pathway is the major route of vesicle production and the relatively minor neuronal AP-3 pathway is not necessary for viability, the absence of the latter could lead to the neurological abnormalities seen in mice lacking the expression of AP-3 in brain. In this study we have identified the first brain-specific function for a neuronal adaptor complex.

Adaptor Proteins, Vesicular Transport↗
PubMed2001

Basolateral sorting of human poliovirus receptor alpha involves an interaction with the mu1B subunit of the clathrin adaptor complex in polarized epithelial cells.

Poliovirus receptor (hPVR/CD155) is a cell surface glycoprotein that belongs to the immunoglobulin superfamily but its natural function remains unknown. Two membrane-bound isoforms, hPVRalpha and hPVRdelta, are known to date, and they differ only in the amino acid sequence of their cytoplasmic domains. To gain an insight into the possible function of the cytoplasmic domains, we examined the localization of introduced hPVRalpha and hPVRdelta in polarized epithelial cells deficient of native hPVRs. Basolateral sorting of hPVRalpha was observed in Madine-Darby canine kidney cells expressing mu1B, but not in LLC-PK1 porcine kidney cells deficient in mu1B. Distribution of hPVRdelta, however, occurred both on the apical and basolateral plasma membranes of these two cell lines. Basolateral sorting of hPVRalpha was also seen in LLC-PK1 cells that expressed an intact exogenous mu1B, but not in the cells that expressed a mutant mu1B lacking binding ability to tyrosine-containing signals. These results indicate that mu1B is involved in the distribution of hPVRalpha to the basolateral membrane. Comparative distribution analysis of hPVRalpha using a series of mutants with truncations and substitutions in the cytoplasmic tail demonstrated that determinant for the basolateral sorting resided in the tyrosine-containing motif of the cytoplasmic tail. Furthermore, yeast two hybrid analysis strongly suggested that the tyrosine motif directly interacted with mu1B protein. Thus, basolateral sorting of hPVRalpha appears to involve the interaction with mu1B through a tyrosine motif existing in the cytoplasmic domain.

Adaptor Protein Complex 1↗