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Biomedical subjects

T Yamazaki

Publications and source records attributed to T Yamazaki.

At least 253 records · Page 14Linked to original sources
PubMed1999

Clinical implication of left precordial T wave inversions in the presence of complete right bundle branch block.

This study was designed to elucidate whether left precordial negative T waves are electrocardiographic indicators for the diagnosis of hypertrophic cardiomyopathy (HCM) even in the presence of complete right bundle branch block (CRBBB). In 7 consecutive patients with CRBBB accompanied by negative T waves in at least one of the left precordial leads (V4, V5, V6, maximal negativity; 1.06 +/- 0.40 mVol) (left precordial negative T wave group) and in 15 randomly selected CRBBB patients without left precordial T wave inversions (control group), echocardiography was performed to rule out underlying diseases causing left ventricular overload and to identify candidates for magnetic resonance (MR) imaging. None had anginal pain indicating ischemic heart disease. When 2-dimensional echocardiography indicated left ventricular hypertrophy with wall thickness > or = 15 mm, the magnitude and distribution of hypertrophy were scrutinized on contiguous left ventricular MR short-axis images. The diagnostic criterion of HCM was the demonstration of hypertrophy with a wall thickness of 20 mm or more on the left ventricular MR short-axis images. All patients in the left precordial negative T wave group had negative T waves in both I (negativity; 0.27 +/- 0.17 mVol) and aVL (negativity; 0.23 +/- 0.14 mVol), whereas none in the control group did. The diagnostic criterion for HCM was fulfilled in six patients in the left precordial negative T wave group. However there were no patients who fulfilled the criterion in the control group. Negative T waves were recorded in the I (negativity; 0.30 +/- 0.17 mVol), aVL (negativity; 0.25 +/- 0.14 mVol), V4 (negativity; 1.03 +/- 0.46 mVol), V5 (negativity; 0.83 +/- 0.37 mVol) and V6 leads (negativity; 0.31 +/- 0.31 mVol) in all patients with HCM, while they were recorded in only 6% of the patients without HCM. In conclusion, the existence of left precordial negative T waves in the presence of CRBBB strongly indicates HCM.

Bundle-Branch Block↗
PubMed1999

Therapeutic efficacy of transcranial magnetic stimulation for hereditary spinocerebellar degeneration.

We applied transcranial magnetic stimulation (TMS) as a therapeutic approach for patients with spinocerebellar degeneration (SCD). The subjects were four familial SCD patients (three men and one woman) aged from 27 to 76 years old. They were genetically analysed as two spinocerebellar ataxia type 6 (SCA 6), one SCA 1, and one SCA 7. The durations of their illness ranged from 1 to 7 years. Ten consecutive magnetic pulses were delivered over the scalp corresponding to the right cerebellar hemisphere, the middle of the cerebellum and the left cerebellar hemisphere, respectively, every day for 21 days. In all patients, the time and the number of steps required for a 10 m walk examination were significantly decreased after TMS trial compared with those before TMS. The number of feasible steps in tandem gait test increased. The total length of tracing body balance for 30 seconds measured by gravinometer was significantly decreased. However, nystagmus, dysarthria or incoordination of the upper limbs did not change after TMS trial. It is of interest that the blood flow of the cerebellar hemisphere, putamen and pons were significantly increased during the TMS trial. Although we do not know the exact mechanism by which TMS improved the ataxic gait, we speculate the increase of blood flow in the cerebellum, putamen and pons takes part in the improvement. These findings suggest that TMS over the cerebellum may be an effective therapy for patients with SCD.

Adult↗
PubMed1999

Gene therapy of chondrosarcoma using retrovirus vectors encoding the herpes simplex virus thymidine kinase gene.

Human chondrosarcoma cells (HCS-TG) were transduced with the gene for a herpes simplex virus thymidine kinase (HSV-tk) or Escherichia coli beta-galactosidase (lacZ). We investigated the cytotoxicity of human chondrosarcoma bearing an HSV-tk gene after treatment with ganciclovir. Chondrosarcoma cells bearing an HSV-tk gene were more sensitive than non-transduced cells. Coculturing with chondrosarcoma cells bearing both an HSV-tk gene (HCS-TG-tk) and lacZ gene (HCS-TG-Z) in various ratios showed a bystander effect. Chondrosarcoma implanted in nude mice were injected with HCS-TG-tk cells. After 4 weeks, the growth of tumors was significantly prevented.

Animals↗
PubMed1999

[Clinical outcomes in low grade follicular lymphoma].

Twenty-six patients with follicular small-cleaved lymphoma (FSCL) and 16 patients with follicular mixed lymphoma (FML) were treated at the Nichidai Itabashi Hospital between 1981 and 1995. The 5-year overall survival rate was 74.3% and 70.0% for the FSCL and FML patients, respectively. Of the patients with stage III-IV FSCL, 9 were assigned to a "watchful waiting" follow-up course and 13 were treated with a single alkylating agent or CHOP therapy. The 5-year failure-free survival rate was 66.7% and 33.0%, respectively. Of the patients with stage II-IV FML, 6 were treated with CHOP or MACOP-B protocol. The complete response rate for this group was only 33.3%, and none of the patients were in remission for more than 2 years. Histological transformation into diffuse aggressive lymphoma was observed in 7 patients, with the median time from diagnosis to transformation at 50 months. Three of those patients were successfully treated with intensive chemotherapy after transformation.

Adult↗
PubMed1999

[Antimicrobial susceptibility testing for Mycobacterium tuberculosis by measuring mycobacterial adenosine triphosphate].

The antimicrobial susceptibility test for Mycobacterium tuberculosis H37Rv and 43 clinical isolates was performed using a bioluminescence assay by measuring the content of adenosine triphosphate (ATP) derived from mycobacteria. The drugs tested were isoniazid (INH), rifampicin (RFP), ethambutol (EB), streptomycin (SM), and kanamycin (KM). The ATP contents of M. tuberculosis incubated in the Middle-brook 7H9 broth medium containing antituberculous agents were measured at days of 0, 1, 3, 5, 7 and 10. A reduction of ATP content, indicating growth inhibition, was observed in susceptible strains within 5 to 10 days of incubation. Optimal concentrations to distinguish between susceptible and resistant strains were determined as being INH 0.20, RFP 0.50, EB 5.0, SM 4.0, KM 6.0 g/ml. The agreements of ATP method (evaluated at 10 days) with Vite Spectrum and MIC determinations were 81.4% and 100%, respectively. Susceptibilities to most drugs, except for EB, could be determined within 7 days. This method is simple, rapid, nonradiometric, and can be used for drug susceptibility.

Adenosine Triphosphate↗
PubMed1999

[A case of true carcinosarcoma in bladder diverticulum].

We report a case of carcinosarcoma arising from a bladder diverticulum. A 71-year-old male was referred to our hospital for macroscopic hematuria. Two diverticula were identified in the left wall of the urinary bladder, one of which showed a broad-based tumor. The bladder tumor was resected using a transuretheral approach and the tumor was histologically diagnosed as leiomyosarcoma. The patient underwent partial resection of the bladder including the two diverticula and the tumor. Pathological examination revealed that the resected specimen was composed of three elements, transitional cell carcinoma (G3), squamous cell carcinoma, and leiomyosarcoma. Thus, the patient was diagnosed with carcinosarcoma. He died 5 months after surgery to remove the panperitonitis carcinomatosa. This case is the 38th reported case of bladder carcinosarcoma in Japan.

Aged↗
PubMed1999

[Advances in endoscopic therapies for cancers of the digestive tract].

Endoscopic therapies for the treatment of cancers of the digestive tract have been improved. Today, some early cancers can be curatively treated by endoscopy (endoscopic polypectomy, endoscopic mucosal resection, heatprobe method, etc.). In addition, endoscopic local injection chemotherapy is performed for some advanced cancers as an adjuvant therapy. Recent progress in endoscopic therapies for cancer is reviewed in this paper, including their historical background. Improvements in these endoscopic treatment methods are expected to provide increased advantages for the treatment of patients with cancer in the near future.

Colonic Polyps↗
PubMed1999

Common mutation of plasminogen detected in three Asian populations by an amplification refractory mutation system and rapid automated capillary electrophoresis.

Congenital deficiency and dysfunction of plasminogen (PLG) are associated with a mild thrombotic tendency. To facilitate the genetic diagnosis of dysPLGemia, we combined an amplification refractory mutation system and rapid automated capillary electrophoresis. Two different fluorescence-labeled PLG-specific primers for exon XV were designed so that each DNA amplified by PCR showed fluorescence of a different wavelength. Single peaks were detected for the normal and the mutant Ala601 -Thr alleles, respectively. A study of 90 normal Caucasians revealed no individuals with the mutation, whereas its gene frequency was 0.021 in Japanese. This mutation was also detected in Korean and Chinese populations at gene frequencies of 0.016 and 0.015, respectively. All of the Korean and Chinese cases with the mutation had at least one haplotype I of the PLG gene, as did most Japanese cases. The high frequency of the Ala601-Thr mutation among these Asian populations may be due to the founder effect.

Asia↗
PubMed1999

[Percutaneous ethanol injection therapy with hepatic arterial infusion chemotherapy for liver metastases from gastric cancer].

Ten patients with liver metastases from advanced gastric cancer received percutaneous ethanol injection therapy (PEI) and chemotherapy by hepatic arterial infusion (HAI) via implantable reservoir. A 90% ethanol solution including 10%. Lipiodol was injected in the liver as PEI.5-FU, EPIR and MMC were used as the regimen for HAI chemotherapy. We have performed this therapy (PEI + HAI) for ten patients with liver metastases since February, 1997. These patients have received this therapy for 4-36 months and three patients died within 16 months. However, three patients did not develop any liver failure after this therapy. The median survival rate was 25.2 months. There are statistically significant differences between upto ss and over se of invasion, and between INF alpha and gamma (p = 0.005).

Aged↗
PubMed1999

In vitro characterisation of two naturally occurring mutations in the thrombin-sensitive region of anticoagulant protein S.

The molecular consequences of two naturally occurring mutations in the thrombin-sensitive region of protein S were investigated using a combination of recombinant protein expression, functional analysis and molecular modelling. Both mutations (R49H and R70S) have been found in thrombosis patients diagnosed as having type I protein S deficiency. Molecular modelling analysis suggested the R49H substitution not to disrupt the structure of thrombin-sensitive region, whereas the R70S substitution could affect the 3D structure mildly. To elucidate the molecular consequences of these substitutions experimentally, site directed mutagenesis of protein S cDNA and expression in mammalian cells created the two mutants. The secretion profiles and functional anticoagulant activities of the protein S mutants were characterised. Secretion of the R49H mutant was similar to that of wild type protein S, whereas the R70S mutant showed moderately decreased expression. Neither of the mutants showed any major functional defects as cofactors to activated protein C (APC) in an APTT-based assay or in degradation of factor Va. However, both mutants demonstrated decreased activity in a factor VIIIa degradation assay, which in addition to APC and protein S also included factor V as synergistic APC cofactor. In conclusion, the R49H substitution did not produce a quantitative abnormality in vitro, raising doubts as to whether it caused the type I deficiency. In contrast, the experimental data obtained for the R70S mutant agrees well with the observed type I deficiency. Our study illustrates that in vitro experimental characterisation together with computer-based structural analysis are useful tools in the analysis of the relationship between naturally occurring mutations and clinical phenotypes.

Binding Sites↗
PubMed1999

[Merocyanine 540-mediated photodynamic therapy inhibits P-glycoprotein (P-gp) activity in adriamycin-resistant K562 cells].

The photosensitizing dye merocyanine 540 (MC540) has been used in preclinical models and in a phase I clinical trial in the U.S.A. for the extracorporeal purging of autologous bone marrow grafts contaminated with leukemia or lymphoma. In this communication, we report MC540-mediated photodynamic therapy (PDT) was effective in purging leukemic cells expressing P-gp. When K562 and K562/ADM were exposed to MC540 (15 micrograms/ml) and white light (145.8 kJ/m2), the concentration of K562 and K 562/ADR was reduced by 1.8 and 3.0 log, respectively. Using flow cytometry and confocal laser scan microscopy, MC540 and calcein-AM were bound intracellularly and effluxed by P-gp in K562/ADM. In K562/ADM, calcein-AM efflux was inhibited by P-gp modulator, cyclosporin A (5 microM) and verapamil (15 micrograms/ml). In contrast, MC540 efflux was inhibited by cyclosporin A but not verapamil. Furthermore, MC540-mediated PDT inhibited efflux of calcein-AM and MC540, and induced the accumulation of dyes in K562/ADM. We conclude that MC540 is a substrate of P-gp and that MC540-mediated PDT is useful for purging MDR cells through inhibition of P-gp activity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

[Compartment analysis of 123I-iomazenil brain SPECT in patients with moyamoya disease].

We investigated 11 patients with moyamoya disease about 123I-Iomazenil kinetics in the brain using three-compartment, two-parameter model. The transition rate constant (K1) from the blood to the brain and the binding potential (BP) of the benzodiazepine to the receptors were calculated for every ROI (right and left side of cerebellum, frontal lobe, parietal lobe, occipital lobe and temporal lobe; 10 ROIs a case). The K1 value correlated with BP value significantly, but not so closely (r = 0.639). And there is no significant difference in BP value among low-K1 group (mean (of K1) -S.D. < or = K1 < or = mean) and high-K1 group (mean < K1 < or = mean + S.D.). This means that CBF and BP do not correlate closely in the average Moyamoya disease patients. And we showed a case with IMP/IMZ discrepancy. The nerve cell in the hypoperfused area which has almost normal BP value is ischemic but viable. IMZ-SPECT presents an important information about the viability of the hypoperfused area in Moyamoya disease patients' brain.

Adult↗
PubMed1999

Eight-year trend of new patients at Clinic for Disabled Patients, University Hospital, Faculty of Dentistry, Tokyo Medical and Dental University.

The trend of new patients was investigated at the Clinic for Disabled Patients, University Hospital, Faculty of Dentistry, Tokyo Medical and Dental University for eight years from 1989 to 1996. The purpose of this study was to explore the future role of this specialized clinic. The study revealed the following information: 1. A total of 1,388 new patients, corresponding to 173.5 new patients per year on average, visited the clinic. 2. The percentage of patients aged 30 or more increased. As a result, the mean patient age rose from 40.4 in 1989 to 47.6 in 1996. 3. Referrals accounted for more than 80% of new patients. Medical doctors referred more patients to our clinic than dentists did. 4. While the percentage of disabled patients tended to decrease, the percentage of medically compromised patients increased. 5. The predominant complaint was dental caries. Patients with cardiovascular diseases also complained of gingival bleeding and ill-fitting dentures. The growing percentage of medically compromised patients and the increasing mean age of patients over the eight-year period seems to reflect advances in medical science and the aging society. These tendencies could be more remarkable in the future. Therefore, much closer cooperation between dentists and medical doctors will be required.

Adolescent↗
PubMed1998

Protein inhibitor of neuronal nitric-oxide synthase, PIN, binds to a 17-amino acid residue fragment of the enzyme.

Neuronal nitric-oxide synthase (nNOS) is the primary nitric oxide (NO) regulator in neurons. The activity of the enzyme is inhibited by a protein inhibitor called PIN. We were able to purify large quantities of PIN overexpressed in bacterial cells. Analytical ultracentrifugation and chemical cross-linking studies showed that PIN exists as a monomer at low concentrations. The protein forms a high order aggregate at elevated concentrations. We have shown, using NMR spectroscopy, that the previously identified PIN-binding domain (PINB) of nNOS (residues 161-245) adopts a random coil structure in solution. By titrating 15N-labeled PINB with unlabeled PIN, the PIN-binding region of nNOS was precisely mapped to a 17-residue peptide fragment from Met-228 to His-244 of nNOS. NMR titration experiments also showed that PIN binds to nNOS with a 1:2 stoichiometry. A synthetic peptide corresponding to the identified PIN-binding region of nNOS was used to study the interaction between PIN and nNOS in detail. The functional implications of the results obtained from this study are discussed.

Amino Acid Sequence↗
PubMed1998

Activation of protein kinase C alpha enhances human growth hormone-binding protein release.

The effect of phorbol ester on human growth hormone-binding protein (hGH-BP) release was investigated. The hGH-BP release from human IM-9 cells measured by immunoblotting was dose-dependently enhanced by a phorbol ester, phorbol 12, 13-dibutyrate (PDBu), and reached plateau at 100 nM. The increased hGH-BP release was shown after 10 min incubation with PDBu and reached a plateau at 60 min after stimulation. Similarly, a diacylglycerol analogue, 1-oleoyl-2-acetyl-sn-glycerol, enhanced hGH-BP release. The enhancement was not inhibited by cycloheximide pretreatment, suggesting that the enhanced hGH-BP release does not require de novo protein synthesis. The PDBu-enhanced hGH-BP release was strongly inhibited by extracellular EDTA, and was dose-dependently inhibited by protein kinase C (PKC)-specific inhibitor, Ro 31-8220. These results suggest that activation of PKC mediates the PDBu-enhanced hGH-BP release. Of the 11 known PKC isoforms in human cells, PKCalpha, delta, mu and iota were detected in IM-9 cells by immunoblotting. Of these isoforms, PKCalpha, delta and mu were present in the membrane fraction, which is a known activation marker of PKC. Furthermore, when several PKC-specific inhibitors (Gö 6976, GF 109203X or bisindolylmaleimide III) with different specificities for each isoform were used, there was a good correlation between inhibition of the enhancement of hGH-BP release and inhibition of the phosphorylation of PKC isoforms, another activation marker of PKC, in PKCalpha but not in PKCdelta and mu. These results suggest that activation of PKCalpha is involved in PDBu-enhanced hGH-BP release.

Carrier Proteins↗