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M Isobe

Publications and source records attributed to M Isobe.

At least 325 records · Page 18Linked to original sources
PubMed1985

The alpha-spectrin gene is on chromosome 1 in mouse and man.

By using alpha-spectrin cDNA clones of murine and human origin and somatic cell hybrids segregating either mouse or human chromosomes, the gene for alpha-spectrin has been mapped to chromosome 1 in both species. This assignment of the mouse alpha-spectrin gene to mouse chromosome 1 by DNA hybridization strengthens the previous identification of the alpha-spectrin locus in mouse with the sph locus, which previously was mapped by linkage analysis to mouse chromosome 1, distal to the Pep-3 locus. By in situ hybridization to human metaphase chromosomes, the human alpha-spectrin gene has been localized to 1q22-1q25; interestingly, the locus for a non-Rh-linked form of elliptocytosis has been provisionally mapped to band 1q2 by family linkage studies.

Animals↗
PubMed1985

Chromosome localization of the gene for human terminal deoxynucleotidyltransferase to region 10q23-q25.

Complementary DNA clones representing the 3' half, the 5' half, and the entire coding region of the human terminal deoxynucleotidyltransferase gene (TdT; DNA nucleotidylexotransferase, nucleosidetriphosphate: DNA deoxynucleotidylexotransferase, EC 2.7.7.31) were used to screen a panel of mouse X human somatic cell hybrid DNAs to determine the chromosomal location of the human TdT gene. The results of the Southern transfer analysis of hybrid DNAs indicate that the gene for TdT is located on human chromosome 10. The in situ hybridization technique was then used to further localize the gene for TdT to region q23-q25 of human chromosome 10.

Chromosome Mapping↗
PubMed1985

p-Nitrophenyl vinyl ether, a novel substrate for the assay of cytochrome P-450 dependent olefinic epoxidation in hepatic microsomes.

p-Nitrophenyl vinyl ether (NPVE) was metabolized to p-nitrophenol and glycolaldehyde via an epoxide by rat hepatic microsomes. The cofactor requirement and effects of monooxygenase inhibitors indicated that the oxidative metabolism of NPVE was mediated by microsomal cytochrome P-450. Epoxide hydrolase plays a minor role, because a strong epoxide hydrolase inhibitor, 3,3,3-trichloropropene oxide, showed a weak inhibitory effect on the p-nitrophenol formation. The epoxy intermediate is so labile that the hydrolysis of the epoxide proceeds mostly nonenzymically even at a neutral pH. Induction experiments suggested that NPVE was susceptible to a wide varieties of cytochrome P-450 species. Thus, a convenient and sensitive method for the assay of olefinic epoxidase activity in hepatic microsomes was developed with NPVE as a substrate.

Animals↗
PubMed1985

Applications of anticardiac myosin monoclonal antibodies in the diagnosis of heart disease.

We have developed anticardiac myosin antibodies, especially monoclonal antibodies, for helping in the diagnosis of heart disease. Our investigations were divided into three research projects. We visualized the distribution of myosin isozymes in human atrial and ventricular myocardium by an immunofluorescence staining method using monoclonal antibodies specific for individual human cardiac myosin isozymes. We also revealed the redistribution of these cardiac myosin isozymes in an overloaded condition. The isozymic pattern of cardiac myosin was changed from the atrial type to the ventricular type in the overloaded atrium. This isozymic redistribution can be considered as physiological adaptive mechanism to meet increased cardiac work during overload. We developed a new method of imaging for myocardial infarction by single photon emission tomography using labelled monoclonal antibody specific for cardiac myosin heavy chain. Specific localization of the labelled antibody was demonstrated in the infarcted area and no accumulation of radioactivity was shown in the bone matrix as observed in 99mTc pyrophosphate images. We developed a sensitive radioimmunoassay of cardiac myosin light chain I (LCI) and demonstrated that peak serum levels of LCI in the patients with acute myocardial infarction correlated well with the left ventricular ejection fraction. Furthermore, LCI release from the infarcted myocardium was not affected by coronary reperfusion due to intracoronary thrombolysis. Thus, serial determinations of serum LCI better quantify the extent of myocardial damage even after coronary reperfusion in acute myocardial infarction.

Antibodies, Monoclonal↗
PubMed1984

A mechanism for epoxidation of cholesterol by hepatic microsomal lipid hydroperoxides.

Evidence was obtained, using cis-stilbene as a model substrate, for the participation of peroxy and/or oxy radicals in epoxidation of cholesterol by rat liver microsomal phospholipid hydroperoxides and a ferrous ion-ADP complex. Under the conditions used, cholesterol was epoxidised to the alpha- and beta-epoxides in the ratio 1:2-4, and cis-stilbene to trans-stilbene oxide without concomitant formation of the cis-oxide. Microsomal phospholipid hydroperoxides could be replaced with methyllinoleate monohydroperoxide for the epoxidation of both substrates. The hydroperoxide-mediated epoxidations were completely inhibited by alpha-tocopherol and t-butylhydroxyanisole. A GLC study suggested that highly polyunsaturated fatty acyl constituents of the microsomal phospholipids might play an important role in epoxidation of the olefinic substrates.

Adenosine Diphosphate↗
PubMed1984

Effects of steroid treatment on release of cardiac myosin light chain II in acute myocardial infarction in dogs.

The effect of methylprednisolone sodium succinate (MP) on release of myosin light chain II (LCII) from the myocardium was studied in experimental myocardial infarction (MI). Acute MI was produced in conscious, closed-chest dogs by ligating the left anterior descending coronary artery beyond the first diagonal branch. MP, 30 mg/kg, was administered intravenously just before and 24 hours after MI. After MI, LCII levels in the serum were determined serially up to 240 hours. MI size was determined histologically 10 days after MI. In the MP group, LCII levels in the serum within 72 hours were lower than in the control, and cumulative LCII release for 3 days decreased from 530 +/- 159 to 310 +/- 101 ng/ml (mean +/- standard deviation) (p less than 0.001). However, the peak LCII level appeared later (control vs MP, 63 +/- 27 vs 122 +/- 25 hours, p less than 0.001), and the peak LCII level and cumulative LCII release for 10 days were not decreased by MP treatment. MI size also was not reduced by MP (11.0 +/- 4.4% vs 11.8% +/- 4.5% of the left ventricle, difference not significant). Since the rate of disappearance of LCII is rapid and was not affected by MP, these results suggest that MP treatment early after acute MI delays breakdown of myosin filaments, but cannot prevent it.

Acetylglucosaminidase↗
PubMed1984

7-Glycidoxycoumarin (GOC): a fluorophotometric epoxide substrate for the assay of glutathione S-transferase activity.

7- Glycidoxycoumarin ( GOC ), a new fluorophotometric epoxide substrate for glutathione S-transferase (GSH TFase ), was conjugated regiospecifically with GSH at pH 6.5 in rat liver cytosol to yield S-(2-hydroxy-3-(7'- coumaroxy )-1-propyl)glutathione which was isolated by HPLC and identified with an authentic specimen by 13C NMR spectroscopy. The conjugation product formed in the incubation media consisting of GOC , GSH, and 9000 g supernatant fractions from various tissues of the rat, was directly determined by photometry of fluorescence emission at 388 nm at an excitation wavelength of 328 nm after removal of the unreacted substrate and its enzymic hydrolysis product, 7-(1',2'-dihydroxy-3'-propoxy)coumarin, by simple extraction with isobutyl alcohol in the presence of a saturating amount of sodium chloride. Stability of GOC at pH 6.5 markedly retarded its autoconjugation with GSH and made the fluorophotometric method sensitive enough to assay small GSH TFase activities in gel column chromatographic fractions as well as in various tissues of the animals. Apparent Km and Vmax for GOC in rat liver cytosol were 55 microM and 7.41 nmole/mg protein/min, respectively. GSH conjugation of GOC was catalyzed by at least two isozymes, E and AA, of hepatic GSH TFases .

Animals↗
PubMed1984

Electrophoretic analysis of pancreatic proteases and zymogen-activating factors in the mouse.

Mouse pancreatic proteases were analyzed by one- and two-dimensional electrophoresis. Active proteases that existed in the luminal fluid were separated into at least eight bands in 8% polyacrylamide gel. Pancreatic proteases activated by intestinal extract were separated into at least seven bands. The mobilities of these bands were exactly the same as those of proteases in the luminal fluid except for those of the most cathodal band. Two kinds of trypsin (Try-I group and Try-II) and one kind of chymotrypsin (Chy-I) were determined by specific and nonspecific protease staining. Try-I group and Try-II were derived from different trypsinogens (Try G-I group and Try G-II), whereas Chy-I was derived from a single chymotrypsinogen (Chy G). Although Try G-II was activated by both intestinal extract and by bovine trypsin, Try G-I group activated only by intestinal extract. Intestinal-activating factors were analyzed by two-dimensional electrophoresis. Mouse enterokinase (enteropeptidase EC 3.4.4.8), which can activate bovine trypsinogen, had a slow mobility. In the intestine of the mouse there are several activating factors in addition to enterokinase. Although it is unclear what intestinal-activating factors can activate Chy G, there is a factor that can convert chymotrypsinogen into chymotrypsin directly. These data suggest that intestinal-activating factors play an important role in the activating mechanisms of mouse pancreatic zymogens.

Animals↗
PubMed1984

Two-dimensional gel analysis of zymogen-activating factors in the small intestine of the mouse.

Zymogen-activating factors in the mouse were investigated by two-dimensional electrophoresis. Mouse pancreatic zymogens--trypsinogen-I group (Try G-I group), trypsinogen-II (Try G-II), and chymotrypsinogen (Chy G)--were purified using DEAE-cellulose column chromatography. Analysis by two-dimensional electrophoresis, using the purified zymogens as substrates, revealed enterokinase isozymes and chymotrypsinogen-activating factors in both the intestinal extract and luminal fluid. Mouse enterokinase was separated into at least two bands in the first-dimensional gel, each able to activate both trypsinogens Try G-I group and Try G-II. Chymotrypsinogen-activating factors were separated into several bands in the first-dimensional gel. Some activating factors showed mobilities similar to those of mouse enterokinase isozymes. Moreover, other activating factors that can activate chymotrypsinogen were present only in the more anodal area of the first-dimensional gel. These findings indicate that at least two enterokinases and several chymotrypsinogen-activating factors play an important role in the process of activating digestive enzymes.

Animals↗
PubMed1984

Leiomyosarcoma of the breast--a case report and an electron microscopic study.

We treated a fifty six-year-old woman with leiomyosarcoma of the breast. Light microscopy showed typical findings of leiomyosarcoma and electron microscopy confirmed the smooth muscle origin of the tumor. The patient is well without evidence of metastases or local recurrence of the tumor fifty-five months after radical mastectomy.

Basement Membrane↗
PubMed1984

Distribution of myosin isozymes in human atrial and ventricular myocardium: comparison in normal and overloaded heart.

We have prepared monoclonal antibodies specific for either atrial or ventricular myosin and defined the isomyosin composition of myocardium in normal and overloaded human hearts. In the atrial myocardium, normal isozymic pattern was V1 dominant which converted to being V3 dominant in an overloaded condition. In contrast, normal isomyosin pattern of the ventricular myocardium was exclusively V3 dominant, and only a small change in the proportion of isomyosin was observed in an overloaded condition. From this, we conclude that isozymic changes in cardiac myosin could occur in the human heart to meet increased work induced by cardiac overload. However, the physiological importance of these isomyosin redistributions in human myocardium seems to be much greater in the atrium than in the ventricle, since larger amounts of V1 isomyosin which could be transformed to V3 isomyosin were present in the atrial myocardium.

Adenosine Triphosphatases↗
PubMed1984

[Hemodynamic determinants of late systolic reversed flow in the main pulmonary artery in pulmonary hypertension: a pulsed Doppler echocardiographic study].

Pulsed Doppler echocardiograms of the main pulmonary artery were evaluated in 46 cases including 23 cases with valvular heart disease, 13 with an intracardiac shunt, two with severe right ventricular failure and low cardiac output state, and eight healthy normals. In each Doppler echocardiogram the sample volume was placed at well defined nine locations within the main pulmonary artery. Among 23 cases with valvular heart disease, 10 cases with pulmonary hypertension showed a late systolic reversed flow ("rebound" pattern : type B) in all nine sample volumes examined. This pattern was neither detected in any cases with normal pulmonary arterial pressure, cases with an intracardiac shunt, cases with low cardiac output state, nor healthy normals. A comparative study of 10 cases with "rebound" pattern (type B) and 13 cases without it disclosed that the former had a significantly increased pulmonary arterial pressure (30.9 + 15.1 mmHg vs 17.8 +/- 9.0 mmHg, p less than 0.001), an increased total pulmonary resistance (789 +/- 496 dynes X cm X sec-5 vs 285 +/- 170 dynes X cm X sec-5, p less than 0.001) and a decreased pulmonary arterial compliance expressed as stroke volume divided by pulmonary arterial pulse pressure (1.75 +/- 0.94 ml/mmHg vs 3.80 +/- 1.65 ml/mmHg, p less than 0.01). Mean acceleration of the pulmonary ejection expressed as peak flow velocity divided by acceleration period was also significantly larger in cases with "rebound" pattern (type B) than in cases with "normal" pattern (938 + 255 cm X sec2 vs 675 +/- 160 cm X sec2, p less than 0.01). In conclusion, "rebound" pattern (type B) in pulmonary hypertension is not simple swirl formation, but a totally reversed late systolic flow in the main pulmonary artery, which is caused by sudden interruption of the distal run-off due to markedly elevated total pulmonary resistance under normal right ventricular ejection.

Adolescent↗
PubMed1983

Sensitive enzyme immunoassay for the quantification of bleomycin using beta-D-galactosidase as a label.

A sensitive and specific enzyme immunoassay (EIA) for an anticancer drug, bleomycin (BLM), has been developed, which allows measurement of as little as 25 pg of the antibiotic/tube. An antibody to BLM was obtained by immunizing rabbits with an antigen prepared by conjugating BLM with mercaptosuccinylated bovine serum albumin via N-(gamma-maleimidobutyryloxy)succinimide as a coupling agent. Enzyme labeling of BLM was performed using beta-D-galactosidase (beta-Gal; EC 3.2.1.23) via N-(m-maleimidobenzoyloxy)succinimide. Free and antibody-bound BLM-beta-Gal conjugates were separated by precipitation of the antibody-bound fraction with a second antibody (anti-rabbit IgG). Displacement of BLM-beta-Gal by unlabeled BLM when plotted as a logit-log function was linear over a concentration range of 10 pg-1 ng. The antibody distinguished alterations in the terminal structure of BLM, showing 277% cross-reaction with BLM B2, 4.6% with A2, 0.42% with A2'-b, 0.13% with A5, and 0.07% with the second-generation analog peplomycin. The EIA is free from interference by other anticancer drugs. Using this assay, drug levels were easily determined in tissues of rats following sc administration at a dose of 500 micrograms/kg. The sensitivity and specificity of the EIA should provide a useful tool for developing pharmacokinetic and toxicity studies of BLM.

Animals↗