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Biomedical subjects

Y Bito

Publications and source records attributed to Y Bito.

At least 19 recordsLinked to original sources
PubMed2006

[Successful off-pump coronary artery bypass for a patient with aplastic anemia].

We report a 61-year-old man with aplastic anemia who underwent successful off-pump coronary artery bypass (OPCAB) after being admitted for angina pectoris. Coronary angiography showed severe stenosis of the left main coronary artery. Preoperative WBC was 2,200/microl, neutrophil 704/microl, Hb 8.1g/dl, and PLT 16,000/microl. We conducted OPCAB on double vessels using left internal thoracic and radial artery grafts. Thirty units of platelets were transfused intraoperatively with little perioperaive hemorrhage. Because of high grade fever, we injected 150 microg granulocyte colony-stimulating factor (G-CSF) every 3 days postoperatively to prevent major infection. The combination of appropriate perioperative management and OPCAB yielded an effective result for a patient with severe hematological disorders causing pancytopenia.

Anemia, Aplastic↗
PubMed2006

[Aortic root replacement in Marfan syndrome with hemophilia A].

A 34-year-old man with Marfan syndrome was admitted to our hospital for surgical treatment of aortic regurgitation due to annuloaortic ectasia. He had no history of bleeding complications. Preoperative investigation revealed a slight prolongation of an activated partial thromboplastin time, which went unnoticed. He underwent aortic root replacement with a composite valve graft. During the operation, he had excessive bleeding due to coagulopathy after the termination of cardiopulmonary bypass, and needed a large amount of blood transfusion to obtain hemostasis. Before his discharge from our hospital, he was diagnosed as mild hemophilia A because of the decline in his factor VII level. To our knowledge, there has been no published case of cardiac operations in Marfan syndrome with hemophilia A.

Adult↗
PubMed2006

[New proximal anastomotic system in coronary artery bypass grafting].

The Heartstring proximal anastomotic system is a device designed to facilitate the creation of a clampless hand-sewn proximal anastomosis. Thirty-four patients who underwent coronary artery revascularization had 40 proximal anastomoses using the Heartstring device. There were 26 men and 8 women, with the mean age of 70 +/- 8.9 years. Thirty-one patients underwent coronary artery bypass grafting through off-pump procedures and 3 patients on-pump beating procedures. In all patients, saphenous vein grafts were anastomosed to the aorta using the Heartstring device, the median number of distal anastomoses being 2.4 +/- 0.7. Either emergent or urgent surgery was required in 14 patients (41%). Diseased aorta was found in 11 patients (32%). One patient (2.9%) died postoperatively due to ischemic necrosis of the small intestine and the colon. There was no occurrence of postoperative stroke. Of 40 saphenous vein grafts anastomosed with the Heartstring system, 39 (97.5%) were patent. The occluded saphenous vein was not considered to be device related. Our clinical experience demonstrated that the Heartstring system allow us to create clampless and reproductive hand-sewn proximal anastomosis and to decrease the incidence of neurological complication.

Aged↗
PubMed2003

[Redo coronary artery bypass operation under beating heart via the left thoracotomy reusing patent grafts].

We report three cases of successful redo coronary artery bypass grafting (CABG) under beating heart via left thoracotomy with recycling of patent grafts previously implanted. Case 1 and 2: Anginal attack relapsed due to occlusion of the proximal portions of saphenous vein grafts (SVG) that had been sequentially anastomosed to the left coronary artery branches. In each case, the distal portion of the SVG was patent and functioned as coronary-coronary bypass. The left internal thoracic artery graft (ITAG) anastomosed to the left anterior descending coronary artery (LAD) was patent. Each patient underwent off-pump CABG through a left posterolateral thoracotomy. CABG was performed with the radial artery to the circumflex coronary artery (case 1) or the circumflex coronary artery and previous SVG (case 2). The proximal ends of radial artery grafts were anastomosed to the descending aorta. Case 3: Simultaneous reoperative CABG and the operation for the pseudoaneurysm that developed after the abdominal aortic graft replacement were performed. Bypass grafting between ITAG and LAD was performed with SVG via a left anterolateral thoracotomy because of severe anastomotic stricture of ITAG-LAD. The postoperative courses was uneventful for all patients.

Aged↗
PubMed2001

Lactate discrimination incorporated into echo-planar spectroscopic imaging.

A technique for discriminating a lactate signal from overlapping lipid signals in (1)H spectroscopic imaging is presented. It is based on J-coupling between lactate protons and on the broad spectral bandwidth of lipid signal. Measurement parameters used in the technique are determined so that TE is separated from n/J (n: a natural number, J: J-coupling constant) enough to suppress the lipid signal at the time when the lactate signal is strongest. Data processing is used to calculate the lactate signal intensity from the reconstructed spectra. This technique enables lactate to be discriminated in a single measurement and enables spectra of other metabolites to be acquired simultaneously. However, it necessitates a homogeneous magnetic field, long TE, and supplementary lipid suppression. Discrimination of the lactate signal is demonstrated by applying lactate-discriminating echo-planar spectroscopic imaging (EPSI), which combines this discrimination technique with the standard EPSI, to rat focal cerebral ischemia models. Magn Reson Med 45:568-574, 2001.

Animals↗
PubMed2001

Mismatch between lactate and the apparent diffusion coefficient of water in progressive focal ischemia.

In this study, we examined mismatch in the area indicated by the normal apparent diffusion coefficient (ADC) of water and increased lactate in the early stage of focal cerebral ischemia. Five rats were subjected to permanent middle cerebral artery (MCA) occlusion. Diffusion-weighted echo planar imaging (DWEPI) and proton echo planar spectroscopic imaging (EPSI) were performed from 20 to 170 min after MCA occlusion, and lactate and N-acetyl asparate images were obtained by EPSI. Postmortem histological analysis was also performed. The areas of increased lactate and normal ADC were observed in the surrounding border zone of ischemia at approximately 20 min after MCA occlusion. This initial lactate in the border zone was significantly higher than that in the normal area, but lower than that in the ischemic core, which showed a reduction of ADC. However, this area was progressively involved in the ischemic core at 170 min without any treatment. The lactate-ADC mismatch in the initial period of ischemia may offer unique diagnostic information for ischemic tissue at high risk, followed by progressive involvement in the ischemic core without treatment. Considering that the accumulation of initial lactate in this area was not excessive, our findings may suggest that the lactate-ADC mismatch in the early period of ischemia indicates potentially salvageable tissue at high risk, requiring aggressive treatment.

Animals↗
PubMed2001

Interactively visualizing data warehouses.

As healthcare costs continue to rise, along with the urgency to control these costs, timely analyses of operational data stored in data warehouses have become critical. Although healthcare organizations have begun to amass large volumes of raw data within data warehouses, many have yet to capitalize on that valuable information. Many clinical and financial events are recorded each day, yet few of these data are leveraged to increase organizational awareness and performance. Because the development and implementation of a data warehouse requires significant time and capital, as well as highly skilled labor, the need to more fully leverage this considerable investment demands techniques that facilitate detailed data exploration, analysis, and the subsequent communication of findings. This article describes how the effective display of complex relationships in data can be used to discover areas of variance in large, changing data warehouses.

Critical Pathways↗
PubMed1996

Expansion of the spectral bandwidth by spatial and chemical shift selective saturation in high-speed magnetic resonance spectroscopic imaging.

A new spectral bandwidth expansion technique for high-speed magnetic resonance spectroscopic imaging (MRSI) based on an echo-planar technique is presented. This expansion can be achieved by spatial and chemical shift selective saturation without increasing the total measurement time. In addition, displacement along the slice-select direction due to chemical-shift differences between the measured compounds is also suppressed. Experimental results are shown using a phantom consisting of benzene and acetone. High spatial resolution (1 x 1 mm2) and wide spectral bandwidth (1.5-1.8 kHz; the effective spectral bandwidth has been doubled) are obtained without the displacement along the slice-select direction.

Echo-Planar Imaging↗
PubMed1995

Echo-planar diffusion spectroscopic imaging.

High-speed diffusion spectroscopic imaging based on an echo-planar technique is presented. A pair of diffusion gradients is applied prior to a rapidly oscillating magnetic field gradient which encodes both chemical shift and spatial information. By applying this technique to a phantom consisting of acetone and water, a diffusion spectroscopic image is obtained in about 15 min, about 64 times faster than the time required in the conventional method. The measured diffusion coefficients show good agreement with previously reported values. This kind of diffusion spectroscopic imaging is expected to provide a way to observe more specific metabolism.

Acetone↗
PubMed1994

[Advance of magnetic resonance spectroscopic imaging (MRSI) techniques].

Magnetic resonance spectroscopic imaging (MRSI) can provide density images of various metabolites in the human body, in vivo, by utilizing chemical shift. This technique has received attention as a new method for analyzing the diseased state, via metabolism. It increases the accuracy of diagnosis and provides hope for early diagnosis of brain disease. However, because a measurement time of more than ten minutes to one hour is required for imaging, it has been difficult to use MRSI techniques for clinical diagnosis. Improved techniques for high-speed imaging have recently been developed. This review describes the recent advances in this field.

Animals↗
PubMed1989

Characterization of activation of a partially defective B cell subpopulation with immunocompetence restricted to IgM and IgA.

A B-cell subpopulation (BM-A cell) responding to an antigen with the production of IgM and IgA plaque-forming cells but not of IgG plaque-forming cells was isolated from neonatally bursectomized chickens and was examined for the mode of activation by B-cell mitogens. The BM-A cells did not elevate both glucose consumption and protein synthesis with the B-cell mitogens, in striking contrast to normal B cells. The BM-A cells were also not activated by an activator of protein kinase C, phorbol myristate acetate. Both anti-Ig and a calcium ionophore, A23187, however, primed the BM-A cells to increase intracellular free calcium ion as well as normal B cells. From these results it is conceived that the lack of protein kinase C activation may be responsible for the failure of activation of BM-A cells.

Animals↗
PubMed1988

The protective effect of a new antiallergic agent, KP-136 on mast cell activation: a comparison with disodium cromoglycate.

The protective effects on mast cell activation were compared between a new antiallergic agent, KP-136 and disodium cromoglycate (DSCG), both of which inhibited the immunological degranulation of rat peritoneal mast cells. The IC50 was 0.03 micrograms/ml for KP-136 and 4.7 micrograms/ml for DSCG. KP-136 predominantly acted on the early stage of mast cell activation processes and inhibited the immunological increase in 45Ca uptake. KP-136 also inhibited A23187- and heat-induced degranulation and heat-induced hemolysis. In addition, KP-136 was effective on phospholipase A2-induced degranulation, although the compound did not directly affect the enzyme activity. In all tests for comparison, KP-136 and DSCG had similar profiles of action and the parallel experiments indicated that KP-136 was a more potent inhibitor of mast cell activation than DSCG, having a DSCG-like membrane stabilizing activity.

Animals↗
PubMed1980

A simple method for detecting cells producing antibodies of specific immunoglobulin classes in the chicken.

A simple plaque method for detecting cells producing antibodies of specific immunoglobulin class in the chicken is described. This method is based upon the inability of chicken antibody to activate guinea-pig complement. IgM- and IgG-specific plaque-forming cells in the spleen of chickens immunized with sheep red blood cells were detected using guinea-pig complement and rabbit anti-chicken-mu- or gamma-chain serum. The specificity of the immunoglobulin class of plaques was confirmed by the abolition of class-specific hemolytic plaques after treatment of the lymphoid cells with rabbit antisera specific for chicken heavy chains in the presence of guinea-pig complement. The method is very simple and rapid, and IgM and IgG specific plaques are reliably detected.

Animals↗
PubMed1980

Gel to liquid-crystalline phase transitions of lipids and membranes isolated from Escherichia coli cells.

Differential scanning calorimetry (DSC) was used to examine the relationship of the gel to liquid-crystalline phase transition of lipids to fatty acid composition with membrane lipids and spheroplast membranes isolated from cells of a wild strain and an unsaturated fatty acid auxotroph of Escherichia coli grown under various conditions. These lipids and membranes underwent thermotropic phase transitions at different temperatures depending on the thermal properties of their constituent fatty acids. The lipid phase transition occurred at higher temperatures in biomembranes than in extracted lipids. DSC thermograms of lipids synthesized by bacterial cells which were observed at a temperature scanning rate as slow as 0.3 K min-1 were characterized by a distinctly plain peak summit. Endothermic peaks given by samples derived from elaidic acid-enriched cells were relatively narrow and asymmetric. The discrepancy between the transition temperatures measured with extracted lipids and with membraneous fractions, and the shape of the endothermic peaks, are discussed.

Calorimetry, Differential Scanning↗