Biomedical subjects

Y Ohnuma

Publications and source records attributed to Y Ohnuma.

8 recordsLinked to original sources

PubMed2001

Mitochondrial ATP-sensitive K+ channels play a role in cardioprotection by Na+-H+ exchange inhibition against ischemia/reperfusion injury.

OBJECTIVES: The possible role of the ATP-sensitive potassium (KATP) channel in cardioprotection by Na+-H+ exchange (NHE) inhibition was examined. BACKGROUND: The KATP channel is suggested to be involved not only in ischemic preconditioning but also in some pharmacological cardioprotection. METHODS: Infarction was induced by 30-min coronary occlusion in rabbit hearts in situ or by 30-min global ischemia in isolated hearts. Myocardial stunning was induced by five episodes of 5-min ischemia/5-min reperfusion in situ. In these models, the effects of NHE inhibitors (cariporide and ethylisopropyl-amiloride [EIPA]) and the changes caused by KATP channel blockers were assessed. In another series of experiments, the effects of EIPA on mitochondrial KATP (mito-KATP) and sarcolemmal KATP (sarc-KATP) channels were examined in isolated cardiomyocvtes. RESULTS: Cariporide (0.6 mg/kg) reduced infarct size in situ by 40%, and this effect was abolished by glibenclamide (0.3 mg/kg), a nonselective KATP channel blocker. In vitro, 1 microM cariporide limited infarct size by 90%, and this effect was blocked by 5-hydroxydecanoate (5-HD), a mito-KATP channel blocker but not by HMR1098, a sarc-KATP channel blocker. Infarct size limitation by 1 microM EIPA was also prevented by 5-HD. Cariporide attenuated regional contractile dysfunction by stunning, and this protection was abolished by glibenclamide and 5-HD. Ethylisopropyl amiloride neither activated the mito-KATP channel nor enhanced activation of this channel by diazoxide, a KATP channel opener. CONCLUSIONS: Opening of the mito-KATP channel contributes to cardioprotection by NHE inhibition, though the interaction between NHE and this KATP channel remains unclear.

Animals↗

PubMed2001

Contribution of both the sarcolemmal K(ATP) and mitochondrial K(ATP) channels to infarct size limitation by K(ATP) channel openers: differences from preconditioning in the role of sarcolemmal K(ATP) channels.

The roles of sarcolemmal ATP-sensitive K+ (sarcK(ATP)) and mitochondrial ATP-sensitive K+ (mitoK(ATP)) channels in the cardioprotection induced by K(ATP) channel openers remain unclear, though the mitoK(ATP) channel has been proposed to be involved as a subcellular mediator in cardioprotection afforded by ischemic preconditioning (PC). In the present study, selective inhibitors of the sarcK(ATP) and mitoK(ATP) channels were used to examine the role of each channel subtype in infarct size limitation by KATP channel openers. Isolated rabbit hearts were perfused in the Langendorff mode with monitoring of the activation recovery interval (ARI) and subjected to 30-min global ischemia/2-h reperfusion to induce infarction. Before ischemia, hearts received 10 microM pinacidil, 100 microM diazoxide, or PC with or without preceding infusion of a sarcK(ATP) channel-selective blocker (5 microM HMR1098) or a mitoK(ATP) channel-selective blocker (100 microM 5-hydroxydecanoate, 5-HD). ARI, an index of action potential duration, was shortened from 118+/-3 ms to 77+/-5 ms after 10 min of ischemia in untreated control hearts. Pinacidil shortened ARI before ischemia from 113+/-2 ms to 78+/-5 ms and enhanced the ARI shortening during ischemia. Diazoxide did not affect ARI before ischemia but accelerated ischemia-induced shortening of ARI. Infarct size as a percentage of the left ventricle (%IS/LV) was reduced by pinacidil and diazoxide from the control value of 47.2+/-4.0% to 4.5+/-1.5% and 5.2+/-1.2%, respectively. HMR1098 significantly inhibited the shortening of ARI by ischemia, pinacidil and diazoxide and partially blocked infarct size limitation by these K(ATP) channel openers (%IS/LV=32.6+/-4.2% and 23.4+/-5.3%, respectively). Infusion of 5-HD did not modify the change in ARI caused by the K(ATP) channel openers but completely abolished cardioprotection (%IS/LV=46.0+/-6.2% with pinacidil and 57.2+/-7.0% with diazoxide). PC with two episodes of 5-min ischemia limited %IS/LV to 21.6+/-4.0%, and this protection was not inhibited by HMR1098. Neither HMR1098 nor 5-HD alone modified infarct size. In conclusion, both sarcK(ATP) and mitoK(ATP) channels may contribute to the anti-infarct tolerance afforded by pinacidil and diazoxide.

Analysis of Variance↗

PubMed2001

[Effectiveness of a new toothbrush with irrigation and suctioning capabilities (ty e-Brush) for removing supragingival plaque].

Patients with dysphagia typically have poor oral health. Because of improper swallowing, they cannot easily and safely clean their mouths. As a solution for such a problem, a manual toothbrush with both irrigation and suctioning functions has been developed, called the "e-Brush". The purpose of this study was to evaluate the cleaning effectiveness of the new e-Brush (9 mm and 11 mm in bristle length) for removing supragingival plaque, compared with a conventional toothbrush, GUM # 211 by Butler. In this study, 12 subjects (12 female of average age 20.6) were selected, and plaque control record (PCR) and scrubbing method were used. The following results were obtained: 1. Significant differences (p < 0.05) were recognized between e-Brush/9 mm (55.54 +/- 18.27%) and the others (e-Brush/11 mm: 30.88 +/- 8.14%, GUM # 211: 35.42 +/- 9.32%). 2. Bristles 9 mm in length were more effective than 11 mm bristles (p < 0.05). 3. Irrigation/suctioning function is more effective than the conventional tooth-brushing method. 4. The irrigation function of e-Brush was meritorious in making almost all users comfortable. These results suggest that this new oral hygiene device, "e-Brush/9 mm", is effective for improving oral care management for patients with dysphagia.

Adult↗

PubMed1998

Two cases of unilateral axillary Paget's disease.

We herein report two cases of unilateral axillary Paget's disease. Extramammary Paget's disease commonly occurs in the anogenital area. Unilateral axillary occurrence is relatively rare. One defect was reconstructed with a pedicled scapular flap, and the other was reconstructed with split-skin graft after excision of the tumor. No recurrence was seen in either patient three years postoperatively. However, although the patient who had been reconstructed with a pedicled flap recovered uneventfully, the other patient, who had been reconstructed with a split-skin graft, suffered from axillary contracture due to the shrinkage of the grafted skin after surgery. A skin graft requires fixation for a long period to prevent shrinkage, which causes axillary contracture. Therefore, from the viewpoint of quality of life, reconstruction using flaps is recommended for axillary lesions.

Aged↗

PubMed1998

Abscess-forming neutrophilic dermatosis: report of three cases associated with hemopathies.

BACKGROUND: The development of different types of neutrophilic dermatosis is reported to occur in the course of malignant hemopathies. These concern mainly Sweet's syndrome, pyoderma gangrenosum, erythema elevatum et diutinum and neutrophilic eccrine hidradenitis. OBSERVATIONS: We have recently encountered the cases of 3 patients who presented all with multiple acneiform papules and dome-shaped aseptic abscesses leaving scars. Pus was sterile in all except case 3 in which slight Staphylococcus aureus growth was shown. However, in this patient, only steroids were effective demonstrating that this bacterium was not responsible for the disease. Histopathology disclosed a dense dermal polymorphonuclear neutrophil infiltrate and some mononuclear cells. Two of these patients had myelodysplastic syndromes while one had IgA myeloma. CONCLUSION: Abscess-forming neutrophilic dermatosis seems to be another type of neutrophilic dermatosis associated with hematological malignancies.

Abscess↗

PubMed1994

A new porous hydroxyapatite ceramic prepared by cold isostatic pressing and sintering synthesized flaky powder.

A new porous hydroxyapatite ceramic was prepared by cold isostatic pressing and sintering of the flaky powder, that was synthesized through two-stage hydrolysis of brushite; (1) a structural change into the apatite structure and (2) a compositional increase in Ca/P ratio, according to the method of Monma and Kamiya. The appearance of the synthesized powder resembled the flaky shape of the starting materials and its average particle size was about 15 microns. This powder consisted of fine needle crystals, which had a tendency to grow into the larger grains, but the powder was highly resistant to sintering under the usual heating conditions at 1200 degrees C. Porous hydroxyapatite blocks and granules were prepared by cold isostatic pressing and sintering a pellet consisting of the hydroxyapatite powder and spherical polymer beads. The product showed a 70% apparent porosity with spherical pores, ranging from 100-200 microns in size, and most pores were interconnected. These properties were ascribed to the effect of cold isostatic pressing on the hydroxyapatite powders with the flaky shape.

Ceramics↗

PubMed1992

Effects of a bone lysine-rich 18 kDa protein on osteoblast-like MC3T3-E1 cells.

A lysine-rich 18 kDa protein was isolated from bovine bone and examined for its effects on osteoblast-like MC3T3-E1 cells. This protein is homologous to a heparin-binding protein in brain and uterus. This protein enhanced cell attachment independent of the Arg-Gly-Asp cell-binding sequence and stimulated proliferation during the growth phase. Addition of this protein to cell cultures on days 11, 12, and 13 after confluency resulted in a 1.6-2.0-fold increase in the alkaline phosphatase activity and little increase in the DNA content. These findings suggest that the 18 kDa protein may be functional in promoting the proliferation and differentiation of osteoblasts.

3T3 Cells↗

PubMed1992

A study on bone induction in hydroxyapatite combined with bone morphogenetic protein.

Our present study consisted of an implantation of artificially made hydroxyapatite (HAP) ceramic pellets under the periosteum of the rabbit skull with subsequent inspection of further progress of bone formation and also of an evaluation of the effects of bone morphogenetic protein (BMP). The results revealed that the alkali phosphatase (AL-P) activity of the pellets was elevated only in those of the bone morphogenetic protein group. The results of determination of bone mineral density at the site of the pellets revealed that the increase in bone mineral density was the most remarkable in the bone morphogenetic protein group rather than the control group. The results of the histopathologic examinations revealed that marginal bone formation was found in the pores on the surface between the pellets and the skull in the control group and in the collagen group, whereas in the bone morphogenetic protein group very active bone formation was found not only on the interface in contact with the skull but also surrounding the whole pellet. It also was noted in the animals in the bone morphogenetic protein group that the pellets were corrupted from the peripheries and then absorbed into the newly formed bone. From these results, the efficacy of the hydroxyapatite-collagen-bone morphogenetic protein complex was made clear, and applications in clinical practice are expected in the near future.

Alkaline Phosphatase↗