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Biomedical subjects

Y Matsui

Publications and source records attributed to Y Matsui.

At least 37 records · Page 2Linked to original sources
PubMed2005

Effect of uncertainties in agricultural working schedules and Monte-Carlo evaluation of the model input in basin-scale runoff model analysis of herbicides.

In the prediction of time-series concentrations of herbicides in river water with diffuse-pollution hydrological models, farming schedules (the dates of herbicide application and drainage of irrigation water from rice paddies) greatly affect the runoff behavior of the herbicides. For large catchments, obtaining precise data on farming schedules is impractical, and so the model input inevitably includes substantial uncertainty. This paper evaluates the effectiveness of using the Monte-Carlo method to generate sets of estimated farming schedules to use as input to a GIS-based basin-scale runoff model to predict the concentrations of paddy-farming herbicides in river water. The effects of using the Monte-Carlo method to compensate for uncertainty in the evaluated parameters for herbicide decomposition and sorption were also evaluated.

Acetanilides↗
PubMed2005

[Acute type A aortic dissection associated with intestinal necrosis].

We report a case with acute type A aortic dissection associated with occlusion of the celiac artery (CA) and the superior mesenteric artery (SMA) who underwent replacement of the aortic valve and the ascending aorta concomitant with CA and SMA bypass grafting and partial resection of the ileum and the cecum. A 79-year-old man who has a history of Y-graft replacement of abdominal aortic aneurysm developed re-dissection of thrombosed type A acute dissection 2 weeks after the onset. We performed CA and SMA bypass grafting followed by replacement of the aortic valve and the ascending aorta. In spite of successful revascularization of the CA and SMA, residual necrosis in the ileum and the cecum necessitated resection of them. He was discharged 11 months postoperatively without neurological sequelae.

Aged↗
PubMed2005

Rapid adsorption pretreatment with submicrometre powdered activated carbon particles before microfiltration.

Manufacturer-supplied powdered activated carbon (PAC) was ground to produce submicrometre particles (0.8 and 0.6 m median diameter) for use as an adsorbent before microfiltration (MF) for drinking water treatment. Batch tests revealed that the microground PAC adsorbed natural organic matter (NOM) much more rapidly and had a higher adsorptive capacity than ordinary PAC. The water samples pretreated with the submicrometre PAC were subjected to MF, and the results of experiments with different PAC contact times revealed that a 1 min retention time was sufficient for adsorptive removal of NOM. The use of submicrometre PAC permitted not only shorter PAC contact times but also a 75% reduction in dose.

Adsorption↗
PubMed2004

Metallic ferromagnet with square-lattice CoO2 sheets.

A single-crystalline film of Sr2CoO4 with square-lattice CoO2 sheets (K2NiF4-type structure) was synthesized, and its electronic properties were characterized. The compound exhibited both ferromagnetic and metallic behaviors, with a fairly high Curie temperature T(C) of approximately 250 K, in contrast to the superconductivity recently found in a triangular-lattice CoO2-sheet compound. The film's large magnetoresistance with current perpendicular to the CoO2 plane showed field-hysteretic behavior analogous to tunneling magnetoresistance. The electronic structure of Sr2CoO4 was also investigated to characterize the quasi-two-dimensional ferromagnetic metal state in terms of optical spectroscopy and first-principles calculation.

Journal Article↗
PubMed2004

Safety of hepatectomy for living donors as evaluated using asialoscintigraphy.

In the living donor operation, accurate estimation of hepatic functional reserve is essential. Technetium-99m-galactosyl-human serum albumin (GSA) is a liver scintigraphy agent that binds to asialoglycoprotein receptors. We evaluated the preoperative assessment of the safety of an elective hepatectomy using GSA liver scintigraphy in 152 patients. GSA scintigraphy was performed after intravenous injection of GSA. The maximal removal rate of GSA (GSA-Rmax) was calculated using a radiopharmacokinetic model. We determined the areas for resection preoperatively depending on the operative procedures and calculated the local GSA-Rmax in the predicted residual liver (GSA-RL). A significant correlation was obtained between the GSA-Rmax and the 15-minute retention rate of indocyanine green. With sub- and monosegmentectomy, 2 patients had postoperative hepatic failure; in those 2 patients, the GSA-RL was 0.127 and 0.133, respectively, but these patients recovered well. Among those having di- and tri-segmentectomy, 5 patients experienced postoperative hepatic failure, in all subjects the GSA-RL was <0.15. Two patients died of postoperative liver failure 1 to 2 months after the operation. We concluded that GSA-RL is useful to select the procedure for hepatectomy in living donors and that GSA-RL should be >0.15 (mg/min/50 kg body weight) to avoid postoperative hepatic failure.

Adult↗
PubMed2004

Functional hepatic regeneration following hepatectomy using galactosyl-human serum albumin liver scintigraphy.

In extended hepatectomy and liver transplantation, accurate estimation of functional hepatic regeneration is more important than volumetric regeneration. We investigated the usefulness of measuring the functional hepatic volume by 99m-technetium galactosyl-human serum albumin scintigraphy (GSA). Extended hepatectomy was performed in 32 patients. These patients were divided into subgroups with or without chronic hepatitis or cirrhosis. Functional hepatic volume GSA scintigraphy (GSA-LV) and determination of hepatic volume by CT (CT-LV) measurements were performed preoperatively, at 2 and 4 weeks and at 3 and 6 months after surgery. The preoperative GSA-LV values were significantly correlated with the hepatocyte volume and the 15-minute retention rate of indocyanine green (ICGR15). Similarly, the hepatocyte volume correlated well with the CT-LV and ICGR15. However, the CT-LV correlated only with the ICGR15. Recovery of the GSA-LV was delayed, and about 90% of the volumetric and functional regeneration was observed within 6 months after the hepatectomy. In contrast, the CT-LV in patients with normal liver remnants returned to approximately 90% of the initial volume within 1 month after the hepatectomy, whereas patients with injured livers regeneration showed gradual recovery to approximately 80% of the preoperative value by 6 months after hepatectomy. We conclude that measurement of functional hepatic volume using the GSA-LV is useful to evaluate hepatic function based on hepatocyte volume.

Carcinoma, Hepatocellular↗
PubMed2004

Classification of portal vein anatomy for partial liver transplantation.

The anatomy of the portal vein is usually classified as 3 to 5 patterns and simple compared with the anatomy of the hepatic artery. The variety of portal vein anatomy was examined in 287 living donors for liver transplantation. More than 90% of donors showed a normal bifurcation type; 6% showed the trifurcation type. Only 3% displayed a separate origin of the right paramedian and the right lateral branches. There was no anomalous pattern that had not been reported previously. In our series, we conclude that it is rare for 2 or more stumps of portal vein to appear in partial liver transplantation. The frequency is much less if the left liver or the right lateral liver graft is used for adult-to-adult living donor liver transplantation.

Functional Laterality↗
PubMed2004

A 3-y prospective study of health-related and disease-specific quality of life in patients with nonmetastatic prostate cancer treated with radical prostatectomy or external beam radiotherapy.

We assessed the longitudinal alteration of the quality of life (QOL) of patients with localized prostate cancer after radical prostatectomy or hormonoradiotherapy during 3-y follow-up. In addition, we examined the impact on QOL of initiation of second treatment after failure of primary treatment. In all, 135 patients with localized prostate cancer who underwent radical retropubic prostatectomy (RP) (N=84) or external beam radiotherapy with neoadjuvant hormone (XRT) (N=51) at our institute and who had a minimum follow-up of 3 y were included in this study. Data were collected prospectively, at baseline, at 3 months after treatment, at 1 y, and annually thereafter. QOL, generic and disease-targeted was evaluated using the European Organization for Research and Treatment of Cancer Prostate Cancer QOL Questionnaire, the Sapporo Medical University Sexual Function Questionnaire, the International Prostate Symptom Index Quality of Life Score and similar questions regarding bowel function. Repeated-measures ANOVA revealed significantly different patterns of alteration in the domains of QOL, with the exception of several domains, between the RP and XRT groups. Rapid decline of sexual function and increase in sexual bothersomeness were followed by slight amelioration throughout follow-up in the RP group, and did not change thereafter in the XRT group. Overall satisfaction with urinary condition significantly improved after treatment and that with bowel condition was stable during follow-up in both of the groups. Failure of primary treatment and initiation of salvage treatment had no impact on QOL. This prospective study revealed longitudinal alteration of QOL status of patients undergoing treatment for localized prostate cancer, but did not yield any conclusions regarding effect of treatment failure and second treatment on QOL due to small sample size. It should be noted that different instruments for assessment of QOL can generate different outcomes.

Aged↗
PubMed2004

Impact of biochemical failure on long-term clinical outcome after radical prostatectomy for prostate cancer in Japan.

Detailed information is needed to understand the impact of biochemical failure (bF) on long-term outcome after definitive therapy for prostate cancer. In all, 223 consecutive men treated with radical retropubic prostatectomy were followed and long-term clinical outcome was investigated. Pathological examination revealed more locally advanced tumors in this study compared with the typical cohorts seen in the Western series. The Cox proportional hazards model indicates pretreatment prostate-specific antigen levels and risk group stratification to be a significant predictors for bF (P<0.05), but not for overall survival. Seminal vesicle involvement was a significant predictor of systemic progression, cancer death and overall survival (P<0.05). Positive surgical margin and bF were also found to be independent predictors of overall survival (P<0.05). In contrast to reports from Western countries, this study found a significant correlation between bF after radical prostatectomy and overall survival. This may reflect years-later detection of prostate cancer in Japan compared with Western series. Biochemical failure may ultimately be translated into decreased overall survival after sufficient follow-up.

Aged↗
PubMed2004

The association of lumbar spondylolisthesis with collagen IX tryptophan alleles.

Two collagen type IX gene polymorphisms that introduce a tryptophan residue into the protein's triple-helical domain have been linked to an increased risk of lumbar disc disease. To determine whether a particular subset of symptomatic lumbar disease is specifically associated with these polymorphisms, we performed a prospective case-control study of 107 patients who underwent surgery of the lumbar spine. Patients were assigned to one of five clinical categories (fracture, disc degeneration, disc herniation, spinal stenosis without spondylolisthesis and spinal stenosis with spondylolisthesis) based on history, imaging results, and findings during surgery. Of the 11 tryptophan-positive patients, eight had spinal stenosis with spondylolisthesis and three had disc herniation. The presence of the tryptophan allele was significantly associated with African-American or Asian designation for race (odds ratio 4.61, 95% CI 0.63 to 25.35) and with the diagnosis of spinal stenosis with spondylolisthesis (odds ratio 6.81, 95% CI 1.47 to 41.95). Our findings indicate that tryptophan polymorphisms predispose carriers to the development of symptomatic spinal stenosis associated with spondylolisthesis which requires surgery.

Adolescent↗
PubMed2004

[Aortic root replacement with free-style stentless valve for aorto-left and right ventricular communication due to infective endocarditis; report of a case].

Aortic root abscess remains a major determinant of both early and late results of surgical treatment of endocarditis. This complication rarely progresses to intracardiac shunt followed by cardiac failure. We report a surgical case of a 40-year-old man, who had been diagnosed as prosthetic valve endocarditis with aortic root abscess ruptured into left and right ventricle creating aorto-left and right ventricular communication. Because of complete debridment of infective and/or dead tissue, aortic root replacement was required. We used free-style stentless valve, xenograft, since homograft was not available at the time of operation. We believe that this prosthesis has easier handling and is more resistant to infection, therefore, it might be an option for infective endocarditis with aortic root abscess.

Abscess↗
PubMed2004

[Aberrant subclavian artery].

Aberrant subclavian artery (ASA) is the most frequently encountered congenital anomaly of aortic arch. The ASA aneurysms are rare but potentially lethal disease, it has been recognized that the presence of an aneurysm of an ASA itself is an indication for surgery. We experienced 4 cases with ASA during the past 23 years. All cases were male. Their ages ranged from 51 to 73 years old. Three patients had a right-sided aortic arch. Among the 4 patients, only 1 underwent total arch replacement, but the other 3 patients could be followed conservatively for 1, 7 and 23 years, respectively. We reviewed the problem of the diagnosis and treatment of the ASA including surgical indication.

Aged↗
PubMed2004

[Ischemic cardiomyopathy treated with overlapping ventriculoplasty].

A 58-year-old man was admitted due to congestive heart failure. Left ventriculography showed end-diastolic volume index (EDVI) of 172 ml/m2 and ejection fraction (EF) of 16%. Coronary angiography showed severe double vessel disease (the left anterior descending artery and the right coronary artery). Echocardiography showed dilated heart [left ventricular end-diastolic diameter (LVDd) of 74 mm] and severe mitral regurgitation due to tethering of the leaflets. The patient underwent our original left ventricular volume reduction operation, termed overlapping ventriculoplasty (OLVP) combined with mitral annuloplasty, papillary muscles plication (PMP) and coronary artery bypass grafting (CABG). The postoperative course was excellent. Postoperatively, the EDVI decreased to 96 ml/m2, the LVDd diminished to 67 mm, and the EF improved to 34%. This case implies the role of left ventricular remodeling procedure of OLVP and PMP in the ischemic cardiomyopathy with ischemic mitral regurgitation.

Cardiac Surgical Procedures↗
PubMed2004

Characterization of microparticles in raw, treated, and distributed waters by means of elemental and particle size analyses.

The elemental composition and particle size distribution of suspended particles in raw water, treated water, and distributed water were determined to understand the behavior of particles during the water treatment-distribution process. The weight of suspended particles collected on a 0.6-microm filter was 1.1 times (raw water), 1.4 times (treated water), and 1.5 times (distributed water) that collected on a 2.7-microm filter, suggesting that smaller particles may remain after conventional water treatment. Organic suspended particles were removed less efficiently than inorganic suspended particles. After sand filtration, the Al content in the fixed suspended solids (FSS) markedly increased, indicating that either a small percentage of aluminium floc passed through during sand filtration or dissolved aluminum precipitated after sand filtration. The Mn and Fe concentrations increased after chlorination. The percentages of carbon and nitrogen in the volatile suspended solids (VSS) were roughly the same in the raw, treated, and distributed waters. The carbon/nitrogen/phosphate/VSS ratios indicated that the VSS of the suspended particles consisted of organic matter originating from microorganisms. The major constituents of the FSS in the treated and distributed waters were compounds of Fe, Al, Ca, Mg, and Mn, but these compounds accounted for only 16% or less of the FSS in raw water, indicating the existence of Si compounds. In distribution pipes, the total suspended solids concentration, especially the FSS concentration, was higher than that of water just after treatment. The Fe concentration in distributed water increased, probably due to oxidation and rusting of iron pipes.

Aluminum↗
PubMed2004

Irreversible and reversible adhesion between virus particles and hydrolyzing-precipitating aluminium: a function of coagulation.

The infectivity of viruses (Qbeta, MS2, T4, and P1) after dosing virus-contaminated water with 4 types of aluminium coagulant was investigated. The concentrations of infectious viruses were determined after dissolving aluminium hydroxide flocs in alkaline solution. The concentration of infectious viruses did not recover to the initial value after a short floc-dissolution time (5 s). Although the infectious virus concentration increased as the floc-dissolution time was extended to 5 h, it did not recover fully. Irreversible adhesion between virus particles and aluminium coagulant is responsible for the insufficient recovery. We interpret this phenomenon as a virucidal activity of the aluminium coagulant. All tested aluminium coagulants (PACl, alum, and reagent grade aluminium chloride and aluminium sulfate) inactivated all types of viruses tested. PACl had the highest virucidal activity. The virucidal activity of aluminium coagulants was lower in river water, presumably owing to the presence of natural organic matter.

Adsorption↗
PubMed2003

Random potential effect near the bicritical region in perovskite manganites as revealed by comparison with the ordered perovskite analogs.

The orbital-charge-spin ordering phase diagram for half-doped perovskites Ln(1/2)Ba(1/2)MnO3 (Ln = rare earth) with ordered Ln/Ba cations has been investigated comparatively with that of the Ln/Ba solid-solution analogs. A large modification of the phase diagram is observed upon the A-site disordering near the original bicritical point between the charge-orbital ordering and ferromagnetic metallic phases. The random potential by quenched disorder inherent in the A-site solid solution is found to suppress the respective long-range orders and gives rise to the colossal magnetoresistive state.

Journal Article↗
PubMed2003

Mucoadhesive properties of carbopol or chitosan-coated liposomes and their effectiveness in the oral administration of calcitonin to rats.

Mucoadhesive liposomes were prepared by coating multilamellar liposomes with Carbopol (CP) in a similar manner to that used in the preparation of chitosan-coated liposomes (CS-Lip) previously reported [Takeuchi et al., Chem. Pharm. Bull. 42 (1994) 1954-1956; Pharm. Res. 13 (1996) 896-901]. The positively charged liposomes containing dipalmitoylphosphatidylcholine (DPPC) and stearylamine at an optimum formulation ratio (40:1) could be coated with CP without aggregation of the liposomal particles during the coating process. The mucoadhesive properties of both the resultant polymer-coated liposomes (CP-Lip and CS-Lip) and the positively or negatively charged noncoated liposomes (Non-Lip) were evaluated using the rat intestine. The order was CS-Lip> or = CP-Lip>positively charged Non-Lip>negatively charged Non-Lip. The adhesive property of CP-Lip decreased on increasing pH of the dispersing medium from pH 5.0 to 7.4, probably owing to the electric repulsion between CP-Lip and the mucus layer. The effectiveness of the liposomal formulations in oral administration of calcitonin was evaluated by measuring the change in the blood calcium concentration of rats. Administration of CP-Lip and CS-Lip containing calcitonin showed an enhanced and prolonged reduction in blood calcium concentration. The overall pharmacological effect of CP- and CS-Lips evaluated by means of the area under the plasma calcium concentration curve was 2.4 and 2.8 times higher than that of negatively and positively charged Non-Lips, respectively.

Acrylic Resins↗