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Biomedical subjects

K Matsuda

Publications and source records attributed to K Matsuda.

At least 55 records · Page 3Linked to original sources
PubMed2002

Sudden deafness: long-term follow-up and recurrence.

We examined the long-term outcome for patients with idiopathic sudden sensorineural hearing loss (sudden deafness), including the incidence of recurrence of sudden deafness. The subjects were 1,798 individuals who came to Nagoya University hospital within 2 weeks of the onset of unilateral sudden deafness. Only 14 of the patients had a history of being diagnosed with sudden deafness. After their visit to our hospital, one patient had a recurrence in the ipsilateral ear and four patients experienced sudden deafness in the contralateral ear. We performed hearing examinations on 88 patients who revisited our hospital more than 10 years after unilateral sudden deafness. Of these patients, there was one with a recurrence in the ipsilateral ear and one with sudden deafness in the contralateral ear. Thus, in this series the recurrence of sudden deafness was rare.

Adult↗
PubMed2002

Simple curettage without bone grafting for enchondromata of the hand: with special reference to replacement of the cortical window.

We studied 23 patients (25 bones) with enchondromata of the hand which were treated with simple curettage without bone grafting. The cortical window was replaced in 18 bones (group A), whereas it was not replaced in six bones (group B). In one bone, only half of the cortical window was replaced. Local recurrence was not seen in any patient. Although bone grafting was not performed, new bone formation was observed in all the patients. Radiographic and functional results were excellent in most bones. Restoration of the continuity of the cortex was seen at 3 (range, 1.5-4) months in group A and 8 (range, 6-12) months in group B. This restoration is important for the recovery of mechanical strength and we therefore consider that the cortical window should be replaced, unless this is impractical.

Adult↗
PubMed2002

Routine endoscopy using a magnifying endoscope for gastric cancer diagnosis.

BACKGROUND AND STUDY AIMS: It has been reported that the fine mucosal patterns of the gastric pits can be observed with magnification and this may assist in preliminary evaluation prior to histological diagnosis. The aim of this prospective study was to clarify the relationship between the fine mucosal patterns of gastric lesions and histological findings, and also to evaluate the usefulness of magnifying endoscopy during routine endoscopy. PATIENTS AND METHODS: A recently developed magnifying video endoscope, which enables magnification up to 80 times, was used for gastrointestinal endoscopy in 318 patients between January 2000 and January 2001, at the National Shikoku Cancer Center. In total, 232 lesions were detected. However, patients diagnosed by conventional endoscopy as having advanced gastric cancer, malignant lymphoma, or submucosal tumor were excluded from the study. The endoscopic findings for 211 lesions included in this study were compared with the histological findings. RESULTS: Coarse and irregular mucosal patterns were observed in elevated-type cancers by magnifying endoscopy, and in depressed-type cancers there was a finer pit pattern than in the surrounding mucosa, destruction or disappearance of the mucosal microstructure, and abnormal capillary vessels. The magnifying endoscopy results were closely related to the mucosal microstructure observed by dissecting microscopy and to the histological features. The rate of presumptive diagnosis of small gastric cancers was significantly higher when a magnifying endoscope was used compared with conventional endoscopy. In this study, the sensitivity and specificity of magnifying endoscopy as a diagnostic method were 96.0% and 95.5%, respectively. CONCLUSIONS: The fine mucosal patterns and the features of capillary vessels, which were identified with the magnifying endoscope, correlated well with the pathological diagnosis. Magnifying endoscopy will be very useful in predicting the histological diagnosis during routine endoscopic procedures.

Gastric Mucosa↗
PubMed2002

Tetrahydrobiopterin restores endothelial function of coronary arteries in patients with hypercholesterolaemia.

OBJECTIVE: To examine the effect of tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthase, on coronary artery endothelial function in hypercholesterolaemic patients. DESIGN: Quantitative coronary angiography and Doppler flowmetry were used to examine the effects of intracoronary infusion of BH4 on vascular response to acetylcholine (ACh). SETTING: Tertiary cardiology centre. PATIENTS: 18 patients with angiographically normal coronary arteries, of whom nine had hypercholesterolaemia and nine had noromocholesterolaemia. INTERVENTIONS: ACh (3 and 30 microg/min) was infused for two minutes into the left coronary ostium. ACh was then simultaneously infused with BH4 (1 mg/min) before and after infusion of L-N(G)-monomethyl-L-arginine (L-NMMA) (40 micromol/min for five minutes). MAIN OUTCOME MEASURES: Diameter of the epicardial coronary arteries and coronary blood flow. RESULTS: In hypercholesterolaemic patients, BH4 attenuated the ACh induced decrease in coronary diameter (p < 0.05) and restored the ACh induced increase in coronary blood flow (p < 0.05). In normocholesterolaemic patients, BH4 did not affect the ACh induced changes in coronary diameter or coronary blood flow. In both groups, L-NMMA decreased the baseline coronary diameter (p < 0.05) and baseline coronary blood flow (p < 0.05). In hypercholesterolaemic patients, L-NMMA inhibited both the BH4 mediated attenuation of the ACh induced decrease in coronary diameter (p < 0.05) and the BH4 mediated enhancement of the ACh induced increase in coronary blood flow (p < 0.01). CONCLUSIONS: Intracoronary infusion of BH4 restores coronary endothelial function by improving the bioavailability of endothelium derived nitric oxide in hypercholesterolaemic patients.

Acetylcholine↗
PubMed2002

The phytochemical lindleyin, isolated from Rhei rhizoma, mediates hormonal effects through estrogen receptors.

Some plant compounds or herb mixtures are popular alternatives to conventional therapies and contain organic compounds that bind to some nuclear receptors, such as the estrogen receptor (ER), to exert various biological effects. We studied the effect of various herbal extracts on ERalpha and ERbeta isoforms. One herbal extract, Rhei rhizoma (rhubarb), acts as an agonist to both ERalpha and ERbeta. The phytochemical lindleyin, a major component of rhubarb, might contribute to this estrogenic activity through ERalpha and ERbeta. 4-Hydroxytamoxifen, an ER antagonist, completely reversed the estrogenic activity of lindleyin. Lindleyin binds to ERalpha in vitro, as demonstrated using a fluorescent polarization assay. The in vivo effect of rhubarb extract was studied using a vitellogenin assay system in the freshwater fish, Japanese medaka (Oryzias latipes). There were marked increases in serum vitellogenin levels in male medaka exposed to rhubarb extract. We conclude that lindleyin, a component of some herbal medicines, is a novel phytoestrogen and might trigger many of the biological responses evoked by the physiological estrogens.

Cells, Cultured↗
PubMed2002

Gene expression analysis from nuclear Poly(A) RNA.

Quantitation of the level of specific mRNA involves the isolation of total RNA or poly(A)+ RNA as a starting materiaL Thus, this result is the sum of the transcription and degradation of mRNA. Here we report a rapid, sensitive, and high-throughput methodology for gene expression analysis from nuclear poly(A)+ RNA via the reduction of the cytosolic components. The cells were first trapped on the glass fiber membranes of 96-well filter plates and subsequently exposed to non-ionic detergent to achieve cell membrane permeation. The cytosolic components, which contain preexisting mRNA, were removed by washing with the appropriate buffer, while nuclei remained in the filter plates. Lysis buffer was then used to release nuclear mRNA, which was collected on oligo(dT)-immobilized PCR plates for the capture of poly(A)+ RNA, on which RT-PCR was performed. The reduction of the cytosolic components and the preservation of the nuclear components were confirmed by electron microscopy, agarose gel electrophoresis, PCR of mtDNA, and RT-PCR of pre-splicing immature beta-actin poly(A)+ RNA. Using this method, we clearly identified UVC-induced p21 gene expression that is not detectable with conventional whole cell methods.

Cell Nucleus↗
PubMed2001

Photoswitching of intramolecular magnetic interaction using diarylethene with oligothiophene pi-conjugated chain.

Diarylethenes having two nitronyl nitroxide radicals at both ends of the molecule with oligothiophene spacers were synthesized. The diradicals underwent photochromic reactions upon alternate irradiation with UV and visible light. ESR spectra of the diradicals reversibly changed with the photochromism. The magnetic interaction between spins through oligothiophene spacers was stronger than that through oligophenylene spacers, and the photochromic reactivity of the diradical diarylethenes with oligothiophene spacers was much reduced. The difference of the exchange interaction between open- and closed-ring form isomers was estimated to be more than 150-fold.

Journal Article↗
PubMed2001

Aberrations in the fragile histidine triad (FHIT) gene in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) seems to be closely associated with lung carcinogenesis. To identify the genetic characteristics of precancerous IPF lesions in the peripheral lung, we performed PCR-based microsatellite analysis with DNA extracted from microdissected tissues; fluorescent in situ hybridization (FISH) analysis of the fragile histidine triad (FHIT) gene and immunohistochemical analysis of Fhit protein expression in samples of metaplasias and bronchiolar epithelia obtained from patients with IPF. We used four microsatellite markers of the FHIT gene within or flanking the FHIT gene on chromosome 3p for loss of heterozygosity (LOH) analysis. LOH of the FHIT locus was frequently found among the lesions of metaplasias and bronchiolar epithelia in the patients with IPF [62 (52%) of 119 informative lesions]. Fifty-four (73%) of the 74 lesions of metaplasias and bronchiolar epithelia obtained from the IPF patients with lung carcinoma and 8 (17%) of the 46 samples obtained from the IPF patients without lung carcinoma showed LOH at the FHIT gene (P < 0.0001). We confirmed allelic loss in the metaplasias and bronchiolar epithelia of IPF by FISH analysis of the FHIT gene. Additionally, the level of Fhit protein expression in the metaplastic cells of IPF was frequently reduced. Our findings suggest that allelic loss of the FHIT gene may be involved in carcinogenesis in the peripheral lung of patients with IPF.

Acid Anhydride Hydrolases↗
PubMed2001

p53R2-dependent pathway for DNA synthesis in a p53-regulated cell cycle checkpoint.

A recently identified ribonucleotide reductase (RR), p53R2, is directly regulated by p53 for supplying nucleotides to repair damaged DNA. We examined the role of this p53R2-dependent pathway for DNA synthesis in a p53-regulated cell cycle checkpoint, comparing it to R2-dependent DNA synthesis. The elevation of DNA synthesis activity through RR in response to gamma-irradiation was closely correlated with the level of expression of p53R2 but not of R2. The p53R2 product accumulated in nuclei, whereas R2 levels in cytoplasm decreased. We found a point mutation of p53R2 in cancer cell line HCT116, which resulted in loss of RR activity. In those cells, DNA damage-inducible apoptotic cell death was enhanced through transcriptional activation of p53AIP1. The results suggest that p53R2-dependent DNA synthesis plays a pivotal role in cell survival by repairing damaged DNA in the nucleus and that dysfunction of this pathway might result in activation of p53-dependent apoptosis to eliminate dangerous cells.

Cell Cycle↗
PubMed2001

Membrane current possessing the properties of a mechano-electric transducer current in inner hair cells of guinea-pig cochlea.

We measured the membrane current possessing the properties of a mechano-electric transducer current in isolated inner hair cells of guinea-pig cochlea. In a free-standing hair bundle, depolarization to +80 mV evoked a stable outward current attributable to the opening of transducer channels, and repolarization to -80 mV evoked a transient inward current indicating adaptation. The time constant of adaptation increased as the membrane potential depolarized. Dihydrostreptomycin diminished both the outward and inward currents.

Animals↗
PubMed2001

Detection of tumor cells in the portal and peripheral blood of patients with colorectal carcinoma using competitive reverse transcriptase-polymerase chain reaction.

BACKGROUND: In spite of many reports, it remains unclear whether the presence of tumor cells in circulating blood flow predicts a poor prognosis. METHODS: Competitive seminested reverse transcriptase-polymerase chain reaction (RT-PCR), a technique for the quantitative detection of tumor cells, was applied to detect the presence of tumor cells in portal and peripheral blood samples from 121 patients with colorectal carcinoma and to clarify their clinical significance. This technique can detect one carcinoembryonic antigen (CEA) mRNA-expressing tumor cell in 1 x 10(5) normal lymphocytes. RESULTS: Six of 33 healthy volunteers (18%) demonstrated a positive reaction to this technique. CEA mRNA expression was detected in the portal blood in 51% of patients and in the peripheral blood in 42% of patients. The results from the two blood samples were consistent in 91% of patients. The positive expression rates for portal blood in patients with T1 tumors and those with TNM Stage I disease were 38% and 45%, respectively. The positive rate was significantly higher in patients with colon carcinoma and those with Stage III or IV disease. CEA mRNA expression, quantitatively measured (x 10(-8)/beta-actin), was 22.9 +/- 35.1 in the portal blood and 19.9 +/- 40.0 in the peripheral blood, with no statistically significant difference. A significant positive correlation was noted between portal and peripheral CEA mRNA expression levels according to Spearman correlation analysis (correlation coefficient = 0.78; P < 0.01). Multivariate analysis revealed that the positive rate and level of CEA mRNA expression in the portal and peripheral blood did not appear to be influenced by the established prognostic factors. CONCLUSIONS: The presence of circulating tumor cells might be of less value as a prognostic factor because they also can be detected in patients with early-stage colorectal carcinoma and appeared to be independent of the conventional prognostic factors.

Blood Specimen Collection↗
PubMed2001

Photochromism of diarylethenes with two nitronyl nitroxides: photoswitching of an intramolecular magnetic interaction.

Photochromic diarylethenes that have p-phenylene-substituted benzothiophene aryl groups with and without nitronyl nitroxide radicals at both ends of the molecules were synthesized. The absorption maxima of the closed-ring isomers showed a hypsochromic shift with the increase in the pi-conjugated chain length. The unique behavior was attributed to the stabilization by the resonant quinoid structures. Both photocyclization and photocycloreversion quantum yields of the diarylethene with nitronyl nitroxide radicals were found to increase with the increase in the pi-conjugated chain length. Photoswitching of the magnetic interaction between two nitronyl nitroxide radicals was studied by means of ESR spectroscopy. The change in exchange interaction between open- and closed-ring isomers of 1,2-bis[6-[4-[4-(1-oxyl-3-oxide-4,4,5,5-tetramethylimidazolin-2-yl)phenyl]phenyl]-2-methyl-1-benzothiophen-3-yl]hexafluorocyclopentene was determined to be more than 30-fold.

Journal Article↗
PubMed2001

Spatially inhomogeneous development of antiferromagnetism in URu2Si2: evidence from 29Si NMR under pressure.

From 29Si NMR study, we present evidence for spatially inhomogeneous development of antiferromagnetic (AF) ordering below T(o) = 17.5 K in URu2Si2. In the pressure range between 3.0 and 8.3 kbar, we have observed the 29Si NMR lines arising from the AF region as well as the previously observed 29Si NMR line which correspond to the nonmagnetic region in the sample. The AF volume fraction is enhanced by applied pressure, whereas the magnitude of internal field at the Si site remains constant (910 Oe) up to 8.3 kbar. In the AF region, the ordered moment is about an order of magnitude larger than 0.03 mu(B)/U.

Journal Article↗
PubMed2001

Glypican-1 is overexpressed in human breast cancer and modulates the mitogenic effects of multiple heparin-binding growth factors in breast cancer cells.

Glypicans are a family of glycosylphosphatidylinositol-anchored cell surface heparan sulfate proteoglycans implicated in the control of cellular growth and differentiation. Here we show that glypican-1 is strongly expressed in human breast cancers, whereas expression of glypican-1 is low in normal breast tissues. In contrast, the expression of glypican-3 and -4 is only slightly increased in breast cancers by comparison with normal breast tissues, and glypican-2 and -5 are below the level of detection by Northern blotting in both normal and cancer samples. Treatment of MDA-MB-231 and MDA-MB-468 breast cancer cells with phosphoinositide-specific phospholipase-C abrogated the mitogenic response to two heparin-binding growth factors, heparin-binding epidermal growth factor-like growth factor and fibroblast growth factor 2. Stable transfection of these cells with a glypican-1 antisense construct markedly decreased glypican-1 protein levels and the mitogenic response to the same heparin-binding growth factors, as well as that to heregulin alpha, heregulin beta, and hepatocyte growth factor. Syndecan-1 was also expressed at high levels in both breast cancer tissues and breast cancer cells when compared with normal breast tissues. There was a good correlation between glypican-1 and syndecan-1 expression in the tumors. However, clones expressing the glypican-1 antisense construct did not exhibit decreased syndecan-1 levels, indicating that loss of responsiveness to heparin-binding growth factors in these clones was not due to altered syndecan-1 expression. Furthermore, 8 of 10 tumors with stage 2 or 3 disease exhibited high levels of glypican-1 by Northern blot analysis. In contrast, low levels of glypican-1 mRNA were evident in 1 of 10 tumors with stage 2 or 3 disease and in 9 of 10 tumors with stage 1 disease. Taken together, these data suggest that glypican-1 may play a pivotal role in the ability of breast cancer cells to exhibit a mitogenic response to multiple heparin-binding growth factors and may contribute to disease progression in this malignancy.

Adult↗