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Biomedical subjects

M Takayama

Publications and source records attributed to M Takayama.

At least 73 records · Page 4Linked to original sources
PubMed1999

Inhibition of lysoPAF acetyltransferase activity by components of licorice root.

Licorice root traditionally used as an anti-inflammatory drug exhibited an inhibitory effect on lysoPAF (platelet-activating factor) acetyltransferase in vitro: the ether soluble fraction of the crude drug produced a 27.3% inhibition at a concentration 10 microg/ml. From this fraction, licoricidin (1), 1-methoxyphaseollin (2), 6,8-diprenylgenistein (3) and 1-methoxyphaseollidin (4) were isolated as active components, whose IC50 values were 7.7, 57, 19 and 48 microM, respectively. Licoricidin (1) seems to be one of the most potent compounds of plant origin isolated so far.

Acetyltransferases↗
PubMed1999

Mutation and transcription analyses of the p63 gene in cervical carcinoma.

Genetic mutation of p53, which monitors DNA damage and operates cellular checkpoints, is a major factor in the development of human malignancies. A novel gene p63/p73L/p51, encoding a protein with significant homology to p53 and p73, was recently identified at 3q27-9. To investigate the penetration of p63 in cervical carcinogenesis, mutation and transcription analyses of p63 were performed in cervical carcinoma. A certain isotype of p63 called TAp63gamma encodes the acidic N-terminus and possesses a short C-terminus. Using reverse transcriptase-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP) analysis for TAp63gamma, one mutation was found in the cervical carcinoma cell line SKG-I. However, no mutations causing amino acid substitutions or frameshifts were found in 54 cases examined for TAp63gamma, which is thought to be a tumor suppressor gene. While cervical carcinomas tended to yield a positive signal in the RT-PCR reaction designed to amplify transcripts encoding the acidic N-terminus, normal cervix and cervical intraepithelial neoplasia (CIN) did not express this transcript. These data suggest that the p63 gene does not play an essential role as a tumor suppressor gene, but expression of TAp63gamma may be speculatively associated with tumor growth in cervical carcinogenesis.

Adenocarcinoma↗
PubMed1999

[Survey of infective endocarditis in the last 10 years: analysis of clinical, microbiological and therapeutic features].

Infective endocarditis still presents problems with early diagnosis, selection of antibiotics and timing of surgical procedure despite modern antibiotics and investigative procedures. A retrospective study was performed to clarify the clinical and microbiological spectrum of recent infective endocarditis in the Japanese population in 38 patients with infective endocarditis (mean age 42.7 +/- 12.5 years) treated from March 1986 to March 1996. The portal of entry to bacteremia was unknown in most cases (57.9%), but the commonest identified portal was dental procedure (18.4%). Overall, the aortic valve was infected most frequently (44.7%) and followed by the mitral valve (36.8%). The most common complication of infective endocarditis were emboli (11/38, 28.9%) and congestive heart failure, NYHA class III and IV (14/38, 36.8%). Organisms were isolated from 26 of the 38 (68.4%) patients. Streptococcus viridans was the most frequent organism (34.2%), and then Staphylococcus aureus (13.2%). The blood culture positivity of microorganism was significantly higher in patients not receiving antibiotics than in those the received antibiotics (87.5% vs 50%, p < 0.05). The prevalence of streptococcal endocarditis decreased in the 1990s (1992-1996) in comparison with those in the 1980s (1986-1988). Multiple antibiotics were used frequently in 1990s and the sensitivity titer to piperacillin reduced from 3.0 in the 1980s to 1.8 in the 1990s. In contrast to reduction of streptococcal endocarditis, Staphylococcus aureus endocarditis has increased recently from 12.5% to 30.8%. The most common clinical features are valve destruction, low sensitivity of penicillin, and significantly higher in-hospital mortality. Surgical treatment was indicated most commonly in cases of uncontrollable heart failure, and infected valves were replaced during the active stage in 11/23 cases (47.8%). In-hospital mortality was higher in the medical treatment group than in the surgical group, but a long-term mortality of mean observation term 4.2 +/- 3.2 years was identical in the chronic phase. In patients with infective endocarditis and successful treatment in the acute stage, a long-term survival rate in medically treated patients was found almost comparable to surgically treated patients in our series. However, it should be emphasized that streptococcal endocarditis is being replaced by infection by Staphylococcus aureus, which is resistant to penicillin and requires intensive chemotherapy and proper decision at suitable timing for surgical therapy in the early stage.

Adult↗
PubMed1999

[Sinusitis].

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Humans↗
PubMed1999

Left coronary artery-left ventricular fistula with acute myocardial infarction, representing the coronary steal phenomenon: a case report.

A 59-year-old man presented with a left anterior descending coronary artery to left ventricular fistula manifesting as myocardial infarction, representing the coronary steal phenomenon. Electrocardiography showed poor R progression in leads V1 through V3. The biochemical markers of myocardial injury were elevated. Creatine kinase level was 509 IU/l, creatine kinase MB isoenzyme (CK-MB)47 IU/l, cardiac troponin T 0.62 ng/ml, myosin light chain 6.1 ng/ml, and myoglobin 142 ng/ml. Thallium-201 myocardial perfusion imaging with dobutamine stress showed a dobutamine-induced perfusion deficit of the anteroseptal wall of the left ventricle with 0.1 mV ST-segment depression in II, III, aVF, V5, and V6. The mean left anterior descending blood flow measured with the Doppler guidewire was increased from 211 to 378 ml/min. Selective coronary arteriography showed dominant left coronary artery with the contrast medium streaming into the left ventricle via a maze of fine vessels from the distal left anterior descending coronary artery. No critical stenosis of the left anterior descending coronary artery was observed. Administration of acetylcholine 100 micrograms into the left coronary artery did not induce vasoconstriction of that artery. The fistula terminating in the left ventricle was ligated surgically and the patient became free of chest pain. Thallium-201 myocardial perfusion imaging with dobutamine stress revealed no perfusion deficit of the anteroseptal wall of the left ventricle. The presence of coronary steal phenomenon was detected by dobutamine stress myocardial imaging.

Coronary Vessel Anomalies↗
PubMed1998

Additional possible tools for identification of proteins on one- or two-dimensional electrophoresis.

Additional, essentially chemical, identification methods of proteins in polyacrylamide gel electrophoresis are described. Two cleavages of peptide bonds were used at the C-side of aspartic acid with a 0.2% pentafluoropropionic acid (PFPA) aqueous vapor at 90 degrees C for 4-16 h, and the N-side of serine/threonine with an S-ethyl trifluorothioacetate vapor at 50 degrees C for 6-24 h. The products were analyzed by mass spectrometry-peptide mass fingerprinting. A new type of C-terminal sequencing at multisites of protein was introduced. An aqueous vapor of 90% PFPA at 90 degrees C for 2-16 h provided cleavages at the C-side of aspartic acid and the N-side of serine/threonine and simultaneous successive truncation at the C-termini of the cleaved fragments. The product resulted in C-terminal sequences at multisites in proteins by mass spectrometric analysis. The following chemical deblocking methods were used. Anhydrous hydrazine vapor at -5 degrees C for 8 h deblocked the N-formyl group, and the vapor at 20 degrees C for 4 h deblocked pyrrolidone carboxylate. N-acetylserine/threonine was deblocked by aqueous vapor of 75% PFPA at 50 degrees C for 1 h, followed by reaction with p-sulfophenylisothiocyanate at pH 6.0. These methods were applied to a variety of protein spots on polyacrylamide gels. A new stepwise C-terminal sequencing of protein from polyacrylamide gels is also described.

Amino Acid Sequence↗
PubMed1998

Low concentrations of adenosine receptor blocker decrease protection by hypoxic preconditioning in ischemic rat hearts.

UNLABELLED: A role for adenosine in ischemic preconditioning and hypoxic preconditioning (HP) has been established in several species but is controversial in rats, due in part to the inconsistency of the data from the different experimental design. Our objective was to investigate the role of adenosine in the protection of the ischemic myocardium by HP in rats. METHODS: perfused hearts isolated from Sprague-Dawley rats were exposed to 5 min of hypoxic perfusion before 25 min of global ischemia followed by 20 min of reperfusion. The effects of adenosine receptor antagonist, 8-(p-sulfophenyl)-theophylline (8SPT) on HP-based changes in left-ventricular function, energy metabolites, and release of creatine kinase and lactate dehydrogenase were determined. To minimise non-specific effects of 8SPT, low concentrations of agent (0.5 or 1.0 micro mol/l) were used. RESULTS: 8SPT alone had no deleterious effects on normoxically perfused hearts or on ischemic/reperfused hearts. HP improved the recovery of LV function and creatine phosphate, and reduced the release of enzymes during reperfusion. 8SPT (1.0 micromol/l) ameliorated the beneficial effect of HP on cardiac function, but did not reverse the reduction in release of enzymes by HP completely. CONCLUSION: results suggest that the protective effect of HP on myocardial contractile function may be mediated by receptor(s) that can be inhibited by low concentrations of antagonist but may not have a primary role in the reduction of cellular damage by HP in rats.

Adenosine↗
PubMed1998

Apoptosis of guinea pig cochlear hair cells following chronic aminoglycoside treatment.

Although aminoglycosides have been investigated for their cochleotoxicity, it has still not been determined whether apoptosis or necrosis results in cochlear hair cell death following aminoglycoside treatment. To study possible mechanisms of cell death, we used in situ DNA break-labeling to examine guinea pig cochleae affected by Kanamycin ototoxicity. Chronic kanamycin treatment induced DNA fragmentation that was detectable in both outer and inner hair cells, suggesting the occurrence of apoptosis. These findings suggest that apoptosis achieves deletion of affected hair cells without disrupting tissue architecture in the organ of Corti.

Animals↗
PubMed1998

Dose-dependent response of vestibular hair cells of guinea pigs following streptomycin ototoxiation.

Although the involvement of apoptosis has been suggested in the loss of vestibular hair cells due to aminoglycosides, dose-dependent effects of aminoglycosides have not been determined. We therefore examined dose-dependent effects of streptomycin on the degeneration of hair cells of guinea pig ampullar cristae using TUNEL stain and Hoechst nuclear stain. Streptomycin induced apoptosis of hair cells in a dose-dependent manner. Even following high-dose applications, most of the affected cells showed apoptotic features. Apoptosis may therefore play a predominant role in the deletion of vestibular hair cells affected by aminoglycosides.

Animals↗
PubMed1998

Role of amino acids in cochlear degeneration: deprivation of cystine induces death of cochlear hair cells of guinea pigs in vitro.

Redox regulation reportedly plays a role in maintaining cochlear homeostasis. However, little is known about the roles of oxidation-reduction systems in the cochlea. We examined the role of the cystine/cysteine oxidation-reduction system in survival of cochlea hair cells in vitro. The survival of hair cells was evaluated in cochlea specimens following incubation with the medium supplemented with various concentrations of cystine. Dying hair cells were detected by the trypan blue extrusion method. The rates of cell death for both outer and inner hair cells increased significantly with a decrease in the concentration of cystine. In addition, the rate of cell death of IHCs tended to be higher than that of OHCs. These findings suggest that the cystine/cysteine system might be required for maintenance of homeostasis in cochlear hair cells, especially in IHCs.

Animals↗
PubMed1998

Role of amino acids in cochlear degeneration: morphological changes in cochlear outer hair cells following glutamate application.

Glutamate is an excitatory neurotransmitter in the cochlea and has toxic effects on the organ of Corti in various pathological conditions. The toxic effects of glutamate have not been determined in detail. In this study, we examined morphological changes in the organ of Corti of guinea pigs following local application of glutamate. Morphological changes were noted in outer hair cells. Degeneration of outer hair cells was found 24 h after glutamate treatment. The extent of degeneration depended on exposure time. Inner hair cells did not exhibit any degeneration. In addition, no degenerative changes were detected in nerve endings attached to hair cells. These findings suggest that outer hair cells are the initial site of degeneration caused by application of excess glutamate to the inner ear.

Animals↗
PubMed1998

Time-dependent response of vestibular hair cells of guinea pigs following high-dose applications of streptomycin.

Apoptosis has been reported to occur in vestibular hair cells following aminoglycoside treatment and is suggested to play a predominant role in deletion of affected hair cells. However, the type of cell death occurring during an acute phase of vestibular damage following high-dose application of streptomycin has not yet been determined. Hence, in this study we examined the cell death mode of vestibular hair cells during the acute phase. The numbers of hair cell nuclei stained by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) method and residual hair cells were quantitatively analysed. Hoechst nuclear staining was used for analysis of the nuclear morphology of affected hair cells. TUNEL staining of hair cell nuclei and lost hair cells began to appear 6 h after streptomycin treatment and increased with more exposure time. Apoptotic nuclear features could also be found from 6 h after streptomycin treatment. These findings support the thesis that apoptosis is a predominant cell death mode in degeneration of vestibular hair cells due to streptomycin ototoxicity.

Animals↗
PubMed1998

Cycloheximide blocks the toxic effect of streptomycin in guinea pig vestibular hair cells.

Apoptosis has been suggested to be a predominant cell death process for streptomycin-induced degeneration of vestibular hair cells. However, the biochemical aspects of this have not been studied. The purpose of this study was to examine the biochemical aspects of apoptosis of vestibular hair cells caused by streptomycin. Cycloheximide is a widely used protein synthesis inhibitor in studies of apoptosis. We therefore investigated cycloheximide effects on degeneration of vestibular hair cells following streptomycin applications. Supplements of cycloheximide significantly prevented DNA fragmentation in hair cell nuclei and reduced the loss of hair cells. This suggests that cycloheximide possibly inhibits apoptosis of hair cells and attenuates streptomycin-induced degeneration of the vestibular epithelium.

Animals↗
PubMed1998

Autologous blood donation preceding coronary artery bypass graft operation in a hemodialysis patient.

A 67-year-old male hemodialysis patient with abdominal aortic aneurysm and triple vessel coronary heart disease required autologous blood donation because of his blood type of Rh(-) before cardiovascular surgery. We performed autologous red blood cell and plasma collection by the switch back method with recombinant human erythropoietin therapy during the 5 weeks before the operation. Autologous platelet collection was also made the day before the operation. These autologous blood donations were safely and successfully performed along with hemodialysis. There was some caution taken for these procedures. The ultrafiltration rate had to be adjusted for blood collection or blood transfusion during hemodialysis in order not to disturb fluid balance. It was necessary to monitor the hyperkalemia of the stored autologous packed red blood cells. For platelet collection, blood in the extracorporeal circuit had to be concentrated because of the presence of renal anemia. Coronary artery bypass graft was safely and successfully performed with the autologous blood only.

Aged↗
PubMed1998

Purulent pericarditis with tamponade caused by Salmonella enteritidis.

The incidence of purulent pericarditis has declined. However, mortality remains high. We describe a case of purulent pericarditis with tamponade caused by Salmonella enteritidis, and emphasize the importance of early recognition, prompt institution of appropriate antibiotic therapy, and early surgical drainage for survival.

Adult↗