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Biomedical subjects

S Matsui

Publications and source records attributed to S Matsui.

At least 19 recordsLinked to original sources
PubMed2000

Initial and 6-month results of biodegradable poly-l-lactic acid coronary stents in humans.

BACKGROUND: Although metallic stents are effective in preventing acute occlusion and reducing late restenosis after coronary angioplasty, many concerns still remain. Compared with metallic stents, poly-l-lactic acid (PLLA) stents are biodegradable and can deliver drugs locally. The aim of this study was to evaluate the feasibility, safety, and efficacy of the PLLA stent. METHODS AND RESULTS: Fifteen patients electively underwent PLLA Igaki-Tamai stent implantation for coronary artery stenoses. The Igaki-Tamai stent is made of a PLLA monopolymer, has a thickness of 0.17 mm, and has a zigzag helical coil pattern. A balloon-expandable covered sheath system was used, and the stent expanded by itself to its original size with an adequate temperature. A total of 25 stents were successfully implanted in 19 lesions in 15 patients, and angiographic success was achieved in all procedures. No stent thrombosis and no major cardiac event occurred within 30 days. Coronary angiography and intravascular ultrasound were serially performed 1 day, 3 months, and 6 months after the procedure. Angiographically, both the restenosis rate and target lesion revascularization rate per lesion were 10.5%; the rates per patient were 6.7% at 6 months. Intravascular ultrasound findings revealed no significant stent recoil at 1 day, and they revealed stent expansion at follow-up. No major cardiac event, except for repeat angioplasty, developed within 6 months. CONCLUSIONS: Our preliminary experience suggests that coronary PLLA biodegradable stents are feasible, safe, and effective in humans. Long-term follow-up with more patients will be required to validate the long-term efficacy of PLLA stents.

Adult↗
PubMed2000

Imaging of the (1)H NMR second moment with (13)C chemical-shift resolution

A method of (13)C chemical-shift-resolved (1)H second moment imaging is proposed for molecular mobility imaging of heterogeneous materials. For evaluating the (1)H second moment, the method relies on the curve fitting procedure using spin-echo shapes indirectly: The information of (1)H echo shapes is transferred to the (13)C signal amplitude through (1)H-(13)C cross polarization and then the curve fitting is made using the (13)C signal amplitude. The (13)C signal is detected under (1)H dipolar decoupling and magic angle spinning, resulting in the incorporation of (13)C chemical-shift resolution. Imaging information is included in the (13)C signal by application of phase-encoding gradients. The second moment images obtained can reflect the molecular mobility at every molecular site separated by (13)C chemical shifts, yielding detailed information on the molecular mobility. The method is demonstrated by spatially 1D experiments performed on a model sample. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Benign schwannoma of the esophagus removed by enucleation: report of a case.

A submucosal tumor of the esophagus was enucleated by a thoracotomy. A microscopic examination showed the tumor to be composed of spindle-shaped cells showing mild nuclear atypia with vague nuclear palisading and scarce mitotic figures. The tumor was surrounded by peripheral lymphoid cuffs. An immunohistochemical study demonstrated diffuse positive staining for S-100 protein in the tumor cells. The lesion was diagnosed to be an esophageal schwannoma based on these pathological features. Benign schwannoma of the esophagus has been described in five cases in four reports in the English literature. This is the sixth case diagnosed by immunohistochemical studies.

Esophageal Neoplasms↗
PubMed2000

Protective effect of bisoprolol on beta-1 adrenoceptor peptide-induced autoimmune myocardial damage in rabbits.

Idiopathic dilated cardiomyopathy is a severe disease of unknown etiology. Accumulating evidence suggests that agonist-like autoantibodies against the beta 1 adrenoceptor in the circulation of dilated cardiomyopathy may play an important role. The aim of this study was to evaluate the effects of the selective beta 1-adrenoceptor blocker, bisoprolol, on beta 1-adrenoceptor peptide induced autoimmune myocardial damage. In the animal model of autoimmune cardiomyopathy induced by active immunization of rabbits with beta 1-adrenoceptor peptide, bisoprolol was given at a dose of 3 mg/day throughout the study period. Our results showed high titer of anti-beta 1-adrenoceptor antibody in the immunized group throughout the study but not in the group receiving only bisoprolol. Cross-reactivity to beta 2 adrenoceptors was observed in some of the immunized rabbits, but disappeared almost entirely after 6 months. As compared to the beta 1-adrenoceptor peptide immunized group without bisoprolol treatment, bisoprolol treated beta 1-receptor peptide immunized group showed increase in the wall thickness and decreases in cavity dimension in anatomical measurements and only mild alterations in macro- and microscopic examinations. Thus, our study clearly demonstrated a beneficial effect of bisoprolol in rabbits who have developed autoimmune myocardial damage.

Adrenergic beta-Antagonists↗
PubMed2000

The usefulness, indications, and complications of laparoscopy-assisted colectomy in comparison with those of open colectomy for colorectal carcinoma.

The technique of laparoscopy-assisted colectomy (LAC) was developed for benign and malignant diseases of the colon and rectum; however, its feasibility and the associated clinical outcome remain unclear. We reviewed 45 patients who underwent LAC (LAC group) and 62 patients who underwent traditional open surgery (Open group) for colorectal carcinoma in our hospital, and compared the clinical data between the two groups in an effort to determine whether LAC is really minimally invasive and if it enhances the quality of life. So that the backgrounds of the patients in both groups were almost the same, we only compared data of patients with colorectal carcinoma of stages 0, I, and II. The duration of surgery in the Open group was significantly shorter for all procedures except sigmoid resection, but the blood loss was not significantly different between any of the procedures except for right colectomy. The time to the first passing of flatus and restarting oral intake, length of hospital stay, and duration of epidural analgesia were significantly shorter in the LAC group. The morbidity and mortality rates in the LAC group were almost the same as those in the Open group at 29.5% and 3.3% versus 22.6% and 1.6%, respectively. However, five major complications of LAC for advanced colorectal carcinomas might be prevented by performing an open procedure. In conclusion, LAC is a safe and minimally invasive surgical technique following which we can expect a faster recovery; however, patients with advanced colorectal carcinomas must be carefully selected for this operation.

Adenocarcinoma↗
PubMed2000

Low molecular weight dextran attenuates increase in extravascular lung water caused by ARDS.

We studied the effect of low molecular weight dextran (mean molecular weight 40,000, Dextran 40; LMD) on the accumulation of extravascular lung water (EVLW), and also on hemodynamics and blood gases, in the oleic acid (OA)-injured lung in pentobarbital anesthetized rats. Starting just before the OA injection (0.01 mL/kg via femoral vein), 10% LMD in lactated Ringer's solution was infused throughout the experiment (5 mL/kg/h) instead of lactated Ringer's solution. OA caused acute lung injury leading to decreased oxygenation (PaO2: 87 +/- 11 mmHg versus control group 128 +/- 11) and an increased permeability of the alveolar-capillary membrane, as shown by increases in EVLW (4.89 +/- 0.54 versus control group 4.07 +/- 0.14), and albumin leakage (0.043 +/- 0.015 versus control group 0.010 +/- 0.004). LMD protected against the increase in EVLW (4.14 +/- 0.10) and the hypoxemia (112 +/- 19 mmHg), but it did not reduce the albumin leakage into the alveolar space (0.052 +/- 0.009). These data suggest that LMD may limit the fluid accumulation that is secondary to OA-induced lung injury.

Albumins↗
PubMed2000

Center of resistance of anterior arch segment.

It is important to know the location of the center of resistance (CR) to control tooth movement. In this study, photoelastic techniques were used to determine the center of resistance. The photoelastic model included the anterior 4 maxillary teeth, which were interconnected firmly with 6 mm of space between lateral incisors and canines. Determination of the CR for the anterior arch segment was based on considerations of a wide variety of load conditions that generated the more uniform stresses in the supporting alveolar bone simulant. For the arch having the anterior 4 teeth connected, the CR was located within the mid-sagittal plane, 6-mm apical and 4-mm posterior to a line perpendicular to the occlusal plane from the labial alveolar crest of the central incisor.

Birefringence↗
PubMed2000

A modification of Mayer's tannic acid-ferric chloride staining method for demonstrating cellular membranous systems for light microscopy.

To observe cellular membranous systems under a light microscope, we modified Mayer's tannic acid-ferric chloride stain method by adding a treatment with hematoxylin after the original procedure. We used the modified tannic acid-ferric chloride (MTA-Fe) stain method to examine kidneys, liver, heart, trachea, epididymides and other organs of rats and dogs. The MTA-Fe stain clearly demonstrated the basement membrane, brush border, basolateral invaginations and cell processes in the kidneys which enabled easy differentiation of the S1 and S3 segments of proximal convoluted tubules. Our technique also demonstrated hepatic cell membranes and bile canaliculi in the liver, cross striations and longitudinal traveling of myofibrils in the heart, cilia of the epithelial cells in the trachea, and stereocilia and terminal bars in the epididymis. The MTA-Fe stain is a convenient method to visualize cellular membranous systems even for light microscopy. The stain has the advantages of using no toxic materials, simple and easy technique, little variation of staining results, and little fading for several months after staining.

Animals↗
PubMed2000

Melleolides K, L and M, new melleolides from Armillariella mellea.

Three new sesquiterpenoid aromatic esters designated melleolides K (1), L (2) and M (3) were isolated from the cultured mycelia of Armillariella mellea (Vahl. ex Fr.) Karst. Structures of these compounds were determined on the basis of various NMR spectral data, chemical transformations and X-ray analysis. Compounds 1, 2 and 3 showed antimicrobial activities.

Agaricales↗
PubMed2000

Application of cis-2-amino-3,3-dimethyl-1-indanol as an efficient chiral auxiliary to the asymmetric Ireland-Claisen rearrangement. Improvement of the diastereoselectivity by combinational use of chlorodimethylsilane as a silylating agent

The asymmetric Ireland-Claisen rearrangement of allyl carboxylates having a chiral substituent at the alpha-position of the carboxylate part gave the desired products with excellent diastereoselectivity, when an oxazolidinone, which was prepared from a non-natural chiral auxiliary, (1R,2S)-cis-2-amino-3,3-dimethyl-l-indanol, was used as the chiral substituent. Furthermore, the diastereoselectivity was improved by using chlorodimethylsilane as a silylating agent of the intermediary enolates.

Journal Article↗
PubMed2000

[Rheumatoid arthritis-associated bronchiolitis successfully treated with erythromycin].

A 52-year-old man with a 4-year history of rheumatoid arthritis, and who had an episode of suspected BOOP in early 1994, was admitted to our hospital because of cough and fever. A chest X-ray film on admission showed small patchy infiltrates, and a computed tomographic (CT) scan showed centrilobular nodules and patchy infiltrates with thickened broncho-vascular bundles in both lungs. Transbronchial and thoracoscopic lung biopsies disclosed the coexistence of interstitial pneumonia with BOOP pattern, follicular bronchiolitis, and diffuse panbronchiolitis-like purulent and obliterative bronchiolitis. Due to findings of chronic sinusitis, the patient was treated with erythromycin for 8 weeks, and the abnormal CT shadows regressed. This was an interesting case of various pulmonary lesions associated with rheumatoid arthritis, and successfully treated with erythromycin.

Anti-Bacterial Agents↗
PubMed1999

Design of clinical trials for recurrent events with periodic monitoring.

This paper presents a design for randomized clinical trials in which incomplete data are collected on the occurrence of potentially recurrent events through periodic monitoring. In particular, events are assumed to arise according to a point process, but information is available at the times of monitoring only if one or more events has occurred since the preceding monitoring point. The event process is modelled via a piecewise Poisson process, and a proportional rates model is introduced to represent the difference in event rates between treatment groups. The design was developed on the basis of a Wald-type test derived from the generalized estimating equations of Liang and Zeger (Biometrika 73, 13-22 (1986)). Robustification of the variance of the estimator of the treatment effect was considered under a random effects model with a semi-parametric mixture distribution. The design was adopted to address issues which arose in an osteoporosis trial conducted in Japan.

Calcium↗
PubMed1999

A human homolog of Drosophila lethal(3)malignant brain tumor (l(3)mbt) protein associates with condensed mitotic chromosomes.

The lethal(3)malignant brain tumor (D-l(3)mbt) gene is considered to be one of the tumor suppressor genes of Drosophila, and its recessive mutations are associated with malignant transformation of the neuroblasts in the larval brain. The structure of D-l(3)mbt protein is similar to Drosophila sex comb on midleg (Scm) protein which is a member of Polycomb group (PcG) proteins. We have isolated here the first human homolog of the D-l(3)mbt gene, designated h-l(3)mbt. Radiation hybrid mapping and fluorescence in situ hybridization (FISH) analysis localized the h-l(3)mbt gene to chromosome 20q12. The h-l(3)mbt transcript is expressed in most of the human adult normal tissues and cultured cell lines. However, some cancer cells markedly reduce the h-l(3)mbt protein expression. Immunocytochemical study revealed that the h-l(3)mbt protein shows a speckled and scattered distribution in interphase nuclei and completely associates with condensed chromosomes in mitotic cells. This subcellular localization has been shown to be different from that of Bmi1 protein which is a component of PcG complex. Furthermore, overexpression of h-l(3)mbt protein by using a Cre-mediated gene activation system leads to failures of proper chromosome segregation and cytokinesis, which result in formation of multinuclei in U251MG cells. These observations suggest that h-l(3)mbt protein has functions distinct from those of PcG proteins and may play a role in proper progression of cell division.

Adult↗
PubMed1999

A model for CD8+ CTL tumor immunosurveillance and regulation of tumor escape by CD4 T cells through an effect on quality of CTL.

Understanding immune mechanisms influencing cancer regression, recurrence, and metastasis may be critical to developing effective immunotherapy. Using a tumor expressing HIV gp160 as a model viral tumor Ag, we found a growth-regression-recurrence pattern, and used this to investigate mechanisms of immunosurveillance. Regression was dependent on CD8 T cells, and recurrent tumors were resistant to CTL, had substantially reduced expression of epitope mRNA, but retained the gp160 gene, MHC, and processing apparatus. Increasing CTL numbers by advance priming with vaccinia virus expressing gp160 prevented only the initial tumor growth but not the later appearance of escape variants. Unexpectedly, CD4 cell depletion protected mice from tumor recurrence, whereas IL-4 knockout mice, deficient in Th2 cells, did not show this protection, and IFN-gamma knockout mice were more susceptible. Purified CD8 T cells from CD4-depleted mice following tumor regression had more IFN-gamma mRNA and lysed tumor cells without stimulation ex vivo, in contrast to CD4-intact mice. Thus, the quality as well as quantity of CD8+ CTL determines the completeness of immunosurveillance and is controlled by CD4 T cells but not solely Th2 cytokines. This model of immunosurveillance may indicate ways to enhance the efficacy of surveillance and improve immunotherapy.

Animals↗
PubMed1999

Effective utilization of N2-ethyl-2'-deoxyguanosine triphosphate during DNA synthesis catalyzed by mammalian replicative DNA polymerases.

Acetaldehyde is produced by metabolic oxidation of ethanol after drinking alcoholic beverages. This agent reacts with nucleosides and nucleotides, resulting in the formation of N2-ethyl-guanine residues. N2-ethyl-2'-deoxyguanosine (N2-ethyl-dG) adduct has been detected in the lymphocyte DNA of alcoholic patients [Fang, J. L., and Vaca, C. E. (1997) Carcinogenesis 18, 627-632]. Thus, the nucleotide pool is also expected to be modified by acetaldehyde. N2-Ethyl-2'-deoxyguanosine triphosphate (N2-ethyl-dGTP) was chemically synthesized. The utilization of N2-ethyl-dGTP during DNA synthesis was determined by steady-state kinetic studies. N2-Ethyl-dGTP was efficiently incorporated opposite template dC in reactions catalyzed by mammalian DNA polymerase alpha and delta. When pol alpha was used, the insertion frequency of N2-ethyl-dGTP was 400 times less than that of dGTP, but 320 times higher than that of 7,8-dihydro-8-oxo-2'-deoxyguanosine triphosphate (8-oxo-dGTP), an oxidative damaged nucleotide. Using pol delta, the insertion frequency of N2-ethyl-dGTP was only 37 times less than that of dGTP. The chain extension from dC:N2-ethyl-dG pair occurred much more rapidly: the extension frequencies for pol alpha and pol delta were only 3.8 times and 6.3 times, respectively, lower than that of dC:dG pair. We also found that N2-ethyl-dG can be detected in urine samples obtained from healthy volunteers who had abstained from drinking alcohol for 1 week before urine collection. This indicates that humans are exposed constantly to acetaldehyde even without drinking alcoholic beverages. Incorporation of N2-ethyl-dG adducts into DNA may cause mutations and may be related to the development of alcohol- and acetaldehyde-induced human cancers.

Adult↗
PubMed1999

Initial and long-term results of angioplasty in unprotected left main coronary artery.

Angioplasty of the unprotected left main coronary artery (LMCA) has been controversial. Although recent single-center studies suggest that new devices may change the situation, many questions and problems remain. Therefore, the results of unprotected left main coronary angioplasty of 175 procedures in 107 patients were analyzed to evaluate its feasibility and effectiveness. The treatment of the initial 107 cases included balloon angioplasty (39 cases, 36%), directional coronary atherectomy (53 cases, 50%), and stents (15 cases, 14%). They were divided into 3 major subgroups: (1) acute group (n = 14), in which LMCA angioplasty was performed in patients with acute myocardial infarction; (2) emergency group (n = 10); and (3) elective group (n = 83). In-hospital mortality was higher in the acute (35.7%) and emergency (40.0%) groups than in the elective group (3.6%; p <0.0001). Angiographic follow-up was routinely performed and the restenosis rate including in-hospital restenosis was 70% in the acute group, 37.5% in the emergency group, and 40% in the elective group (p = NS). The mean clinical follow-up period was 2.9 years, and the estimated 5-year survival rates of the acute and emergency groups were 50% and 48.2%, respectively. However the 5-year survival rate of the elective group was higher than that seen in the acute or emergency group (77.5%; p <0.05). Repeat LMCA angioplasty was performed in 37 of 68 patients with 8.8% mortality (38.5% of acute and emergency cases and 1.8% of elective cases). The results indicated that elective unprotected LMCA angioplasty is relatively feasible and effective under scheduled angiographic follow-up.

Adult↗