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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 577 records · Page 32Linked to original sources
PubMed1993

The development and practical use of information systems in the pharmaceutical industry.

To provide information on the efficacy, safety, and quality of medicine promptly and accurately, we have developed two databases: a literature database with numerical data, and a Drug Information database. By an easy-to-use, company-wide information network system, over 1,000 medical representatives in more than 80 offices throughout Japan can retrieve information. Information derived from the system is displayed on the terminal and the original documents are automatically output through a facsimile.

Databases, Bibliographic↗
PubMed1993

Surgical treatment of congenital biliary dilatation associated with pancreaticobiliary maljunction.

The excisional surgical treatment of 50 patients with congenital biliary dilatation (CBD) associated with pancreaticobiliary maljunction (PBMJ) was analyzed. There were two patients who had early complications of lesser bile juice leakage with a maximum duration of 21 days, but no pancreatic juice leakage was noticed. As a late complication, two strictures at the anastomotic portion of the hepaticojejunostomy and one intrahepatic gallstone formation were encountered, but no malignant lesion was evident. Both patients with strictures could be predicted using postoperative cholangiography performed two weeks postoperatively and underwent hepaticojejunostomy. Intrahepatic gallstones were treated with lateral segmentectomy of the liver and electrohydraulic lithotripsy through percutaneous transhepatic cholangioscopy. Accordingly, these results suggest that excisional surgical treatment is the most appropriate method for CBD with PBMJ; however, special care must be taken, such as creating a sufficiently wide anastomotic stoma to enable free drainage of bile into the intestine; also, there should be precautions against ischemia at the anastomotic portion. The importance of the postoperative cholangiography to predict the postoperative outcome should be emphasized. Furthermore, causes of intrahepatic gallstone formation should be studied in such instances.

Adolescent↗
PubMed1993

[Airway hyperreactivity test by measurement of specific airway conductance during quiet breathing].

In asthmatic patients, the threshold for specific airway conductance during quiet breathing (sGawqt) in the airway hypersensitivity test was determined using our newly developed pressure corrected flow type body plethysmograph and compared with that measured by means of respiratory resistance (Grs) Astograph in relation to the following parameters: 1) Dmin, an index of airway sensitivity (accumulated methacholine concentration at the time of onset of linear decrease in the dose-response curve), 2) SsGawqt and SGrs, indicators of airway sensitivity (slope when the value begins to decrease) and 3) PD35 (accumulated methacholine concentration when the valve has decreased to 35% of the initial value). Although no significantly difference was observed in SsGawqt and SGrs, significantly lower values of Dmin and PD35, indexes of airway sensitivity, were obtained with sGawqt method as compared to Astograph. These findings may indicate that the airway hypersensitivity test using our body plethysmography technique can be performed using a smaller amount of inhaled methacholine with less patient burden as compared to Astograph.

Adult↗
PubMed1993

[Eosinophil activation evaluated by using a anti-human secreted form of ECP antibody (EG2)].

EG2 is a monoclonal antibody which recognize activated eosinophils, and the increased number of eosinophils stained by EG2 suggest activation of the disease. In bronchial epithelium of patient with asthma, not only EG2-positive eosinophils but CD25-positive T lymphocytes are increased, and support the theory that asthma is a nonsuppurative inflammatory disease of bronchial tree. Bronchial hyperresponsiveness of patient with asthma, which was assessed by a methacoline provocation test, was correlated significantly with the number of EG2 positive-eosinophils in bronchial epithelium. Moreover, most of eosinophils infiltrated to bronchial epithelium in patient with fatal asthma were EG2 positive. The severity of acute asthma attack however did not correlate with EG2-positive rate of eosinophils, but significantly correlated with releasability of granules from eosinophils in sputum of patients with asthma indicated by BMK-13 staining. There are many reports that EG2-positive eosinophils participate in the pathogenesis of other allergic diseases, several types of collagen disease and cancer therapy.

Antibodies, Monoclonal↗
PubMed1993

[Interleukin-1 beta production by alveolar macrophages in cases of asbestos exposure].

In order to investigate the role of interleukin-1 beta secreted by alveolar macrophages in the pathogenesis of pulmonary asbestosis, we performed bronchoalveolar lavage on 12 asbestos-exposed subjects and 10 control subjects, and measured interleukin-1 beta secreted by alveolar macrophages. Interleukin-1 beta production was increased in the asbestos-exposed subjects compared to control subjects (3.1 +/- 2.2 ng/ml versus 0.8 +/- 0.4 ng/ml, p < 0.05). The period after retirement was inversely correlated with interleukin-1 beta production (r = -0.67, p < 0.05). We divided non-smoking asbestos-exposed subjects into two subgroups based on the radiographical profusion according to the ILO classification. The advanced group was defined as grade 2 or greater profusion, and the early group was defined as grade 1 or lower profusion. We found higher production of IL-1 beta in the early group than in the advanced group.

Aged↗
PubMed1992

Effects of 1,3-chelation induced by cis-diamminedichloroplatinum(II) on the stability of DNA duplexes.

Several 1,3-intra-strand cross-linked decadeoxynucleotide duplexes, modified with cis-diamminedichloroplatinum(II) (cis-DDP), and their base substitution analogues at the complementary site to the intervening base of the coordination sites, were synthesized and measured for UV-melting profiles to determine melting temperature (Tm) values. The results indicated the thermal stability of the oligonucleotide duplexes containing Pt-induced 1,3-intra-strand cross-linking did not depend on the kind of intervening base of the coordination site but rather on its complementary base. These results may explain the mutagenicity of cis-DDP from a chemical aspect.

Base Sequence↗
PubMed1992

Reduction of alpha-tocopherolquinone to alpha-tocopherolhydroquinone in rat hepatocytes.

The contents of alpha-tocopherolhydroquinone (TQH2), alpha-tocopherolquinone (TQ) and alpha-tocopherol (Toc) in isolated rat hepatocytes and liver homogenates were determined by HPLC under anaerobic conditions, because TQH2 easily autoxidizes to TQ under aerobic conditions. The viable hepatocytes were used for the determination without homogenization. The hepatocytes contained 3.1, ND and 5.0, 3.1-9.0, and 31.3-63.2 nmol of TQH2, TQ and Toc/g liver, respectively. However, TQH2 was not detected in liver homogenates because endogeneous TQH2 autoxidizes to TQ during preparation of homogenates under aerobic conditions. The homogenates contained 2.0-23.5 and 36.5-54.9 nmol of TQ and Toc/g liver, respectively. Addition of TQ showed that TQ was reduced and converted into TQH2 in isolated hepatocytes. The TQH2 formation from TQ was also observed in liver homogenates in the presence of either NADPH or NADH. The formation was further analysed and confirmed by HPLC and mass spectrometry. The formation of TQH2 was also found to occur in mitochondria, microsomes and cytosol. The specific activity of NADPH-dependent TQ reductase activity was in the order of mitochondria greater than or equal to microsomes greater than cytosol. Furthermore, NADPH-cytochrome P450 reductase was found to catalyse TQH2 formation from TQ.

Animals↗
PubMed1992

Stabilization of human neutrophil NADPH oxidase activated in a cell-free system by cytosolic proteins and by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide.

The superoxide-generating respiratory burst oxidase (NADPH oxidase) from human neutrophils can be activated in a cell-free system consisting of plasma membrane and cytosol by anionic amphiphiles such as sodium dodecyl sulfate and arachidonate (McPhail, L. C., Shirley, P. S., Clayton, C. C., and Snyderman, R. (1985) J. Clin. Invest. 75, 1735-1739; Curnutte, J. T. (1985) J. Clin. Invest. 75, 1740-1743; Bromberg, Y., and Pick, E. (1984) Cell. Immunol. 88, 213-221). Herein, the activity thus obtained is shown to be very labile at 37 degrees C. The rate of inactivation varied inversely with cytosol concentration. The stabilizing factor(s) was destroyed by heat and trypsin, indicating that it is protein in nature. Whereas cytosol from normal cells and from a chronic granulomatous disease patient lacking p67phox stabilized the oxidase activity, that from a chronic granulomatous disease patient lacking p47phox did not. Also, dialdehyde NADPH-treated cytosol showed no stabilizing effect, indicating that p47phox and a putative NADPH-binding component both participate in stabilization. The mechanism of inactivation was further explored by examining the stabilizing effect of agents that can act as chemical cross-linkers. Of several tested, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) was the most effective, but others that utilize different chemical mechanisms were also partially effective. EDC extended the half-life at 37 degrees C from 2 to 120 min, protected against the inactivating effects of Triton X-100 and high salt, and did not affect the Km for NADPH. Stabilization required prior activation in the presence of both cytosol and membrane; and EDC treatment of cytosol, membrane, or a mixture of the two prior to the addition of sodium dodecyl sulfate failed to induce stabilization. EDC eliminated the requirement for the continuous presence of cytosol and activator. Dialysis did not cause a loss in activity, whereas control activity was diminished with dialysis and was largely restored with added sodium dodecyl sulfate. In the absence of EDC, the separation of cytosol from the membrane fraction resulted in a significant loss of activity, which was largely restored by the addition of cytosol. However, EDC treatment allowed the isolation of a nearly fully active oxidase in the membrane fraction, the activity of which was not influenced by added cytosol. These results support a model in which the active NADPH oxidase consists of a dissociable complex among membrane and cytosolic components and indicate that the longevity of the activated state requires continuous association of these components.

Cell Membrane↗
PubMed1992

Spermine down-regulates superoxide generation induced by fMet-Leu-Phe in electropermeabilized human neutrophils.

Effect of spermine, a naturally occurring polyamine, was investigated on superoxide generation in intact and electropermeabilized human neutrophils. Spermine suppressed N-formyl-methionyl leucyl phenylalanine (fMLP)-induced superoxide generation in permeabilized cells by reducing the rate and shortening the duration time. The inhibition was specific for spermine comparing with its precursor amines, spermidine and putrescine. The inhibition was not observed when cells were preincubated with spermine without permeabilization. Concanavalin A-induced superoxide generation was also down-regulated by spermine in permeabilized cells, but the activation induced by non receptor-mediated agonist (dioctanoylglycerol, phorbol myristate acetate, and arachidonate) was not affected by spermine. On the other hand, GTP-gamma-S-induced activation of superoxide generation was substantially suppressed by spermine. These results indicate that spermine inhibition occurs at a step prior to protein kinase C in signal transduction or in a pathway which is independent of the kinase.

Cell Membrane Permeability↗
PubMed1992

The simultaneous measurement of the redox state of cytochrome oxidase in heart and brain of rat in vivo by NIR.

The mutual relationship of the redox state of cytochrome oxidase in both cardiac and brain tissues were examined by the simultaneous optical measurement. The oxygenation states of cardiac and brain tissues behaved in a same manner during progressive hypoxia. We concluded that the oxygenation state of brain completely depends on the oxygenation state of cardiac tissue which determines the cardiac output.

Animals↗
PubMed1992

Cerebral oxygenation state in chemically-induced seizures in the rat--study by near infrared spectrophotometry.

The hemoglobin oxygenation state and the redox state of Cyt.ox. in the rat brain during and after seizure induced by PTZ were measured by using near-infrared spectrophotometry. PTZ administration caused transient reduction of Cyt.ox. in the brain, which might be a trigger for the increase of CBF during seizure. In postictal phase, although BP remained high, Cyt.ox. was in the certain reduced state, which might be due to A-V shunt. Hypoxic loading during seizure caused more reduction of Cyt.ox. than under non-epileptic conditions, which meant that seizure even under mild hypoxic conditions could cause severe hypoxic brain damage.

Animals↗
PubMed1992

Suprasellar germinomas; relationship between tumour size and diabetes insipidus.

The clinical and neuro-endocrinological aspects of 17 suprasellar germinoma patients treated between 1972-1991 are reported. Surgical extirpation was not initially attempted, but all patients received irradiation with or without a biopsy. Sixteen of those have led useful lives with appropriate hormonal replacement therapy during a mean follow up of 8 years. Seven tumours at diagnosis were less than 2 cm in diameter (type 1), nine tumours more than 2 cm (type 2), and one double midline tumour was of unknown size. All 7 type 1 patients required 1-deamino-8-D-arginine-vasopressin (DDAVP) to control diabetes insipidus (DI), but only 2 of the 9 type 2 patients have needed DDAVP since completion of the treatment. Patients with smaller tumours required more DDAVP following tumour disappearance, than those with larger tumours. The prognostic indicators for the post-treatment course of DI and retarded growth appeared to be the tumour size and the age at diagnosis. We also emphasize the absence of metastasis in unoperated cases and the use of tumour markers as a diagnostic criterion which obviates surgical acquisition of tissue to make the diagnosis. Possible reasons are discussed and the literature reviewed.

Adolescent↗
PubMed1992

The additive effect of alpha-difluoromethylornithine (DFMO) and radiation therapy on a rat glioma model.

The effects of alpha-difluoromethylornithine (DFMO), radiation and the therapy of their combination were investigated in rats bearing G-XII glioma. DFMO treatment as well as radiation therapy prolonged the survival period when compared to the results in non-treated control rats. The combination therapy showed a greater effect on the survival rate than the single therapies, the effect being additive. The concentration of putrescine, spermidine, and N1-acetylspermidine in tumor tissue was lowered by DFMO, while that of spermine was slightly elevated. Radiation decreased the concentration of all the polyamines, putrescine, spermidine, spermine and N1-acetylspermidine. The concomitant treatment with DFMO and radiation further decreased the concentrations of putrescine and N1-acetylspermidine in tumor tissues. The survival period of glioma-bearing rats is inversely correlated with the tissue levels of putrescine plus N1-acetylspermidine.

Animals↗