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Biomedical subjects

M Katayama

Publications and source records attributed to M Katayama.

At least 235 records · Page 13Linked to original sources
PubMed1989

Levels of protein kinase C activity in human gastrointestinal cancers.

The protein kinase C (PKC) activities of tumor tissue and adjacent normal mucosa of human cancers of the esophagus (8 cases), stomach (1 case) and colon (3 cases) were measured. Considerable variations were found in the activity of PKC and in its subcellular distribution in these cancers. The PKC activities of the membrane and cytosolic fractions of the eight esophageal cancers were, however, similar to those of the adjacent normal mucosa: the average PKC activities of the tumor tissues and normal mucosa were 7.5 and 8.3 pmol/min/mg protein, respectively, in their membrane fractions and 7.9 and 7.8 pmol/min/mg protein, respectively, in their cytosolic fractions.

Cell Membrane↗
PubMed1989

Vector U loop in patients with old myocardial infarction.

The U loop of the vectorcardiogram was examined qualitatively and quantitatively in 100 normal subjects and 67 patients with old myocardial infarction, using a direct-writing vectorcardiograph with memory function. In the control group, the U loop was directed to the left, anteriorly and inferiorly, and it was inscribed counterclockwise in the horizontal plane. In patients with anterior myocardial infarction, the U loop tended to be displaced to the right, and in patients with inferior myocardial infarction to the right and superiorly. The shape of the U loop in patients was also different from that of normal subjects. The maximum U vector was significantly smaller in magnitude both in patients with anterior and inferior myocardial infarction than that of normal subjects (p less than 0.01). In patients with ventricular aneurysm, the magnitude of the maximum U vector was significantly smaller and its direction was displaced more to the right and posteriorly than those without aneurysm (p less than 0.01). In standard 12-lead electrocardiogram (ECG), observation of the U wave in patients with old myocardial infarction was difficult, especially in the limb lead, because of the small size of the U wave. Therefore, vectorcardiographic observation may be more useful than electrocardiographic observation for the analysis of the U wave in patients with old myocardial infarction.

Adult↗
PubMed1989

Isolation and characterization of two monoclonal antibodies that recognize remote epitopes on the cell-binding domain of human fibronectin.

Two monoclonal anti-fibronectin antibodies that inhibit fibronectin-mediated cell adhesion have been established and characterized. One antibody, FN12-8, inhibited attachment of rat kidney fibroblasts on the fibronectin-coated substrate in a concentration-dependent manner, attaining a maximal inhibition of greater than 85% at 850 micrograms/ml. Another antibody, FN30-8, caused about 70% inhibition at a concentration as low as 0.85 microgram/ml, although further increase of the antibody concentration did not significantly augment the inhibitory effect. Immunoblot analysis with defined proteolytic fragments revealed that both antibodies are directed to the cell-binding domain of fibronectin. The epitopes for these antibodies were further narrowed down using recombinant cell-binding fragments expressed in Escherichia coli. FN12-8 recognized the 11.5-kDa cell-binding fragment previously characterized by Pierschbacher et al. (1981, Cell 26, 259-267), suggesting that FN12-8 blocks the Arg-Gly-Asp (RGD) cell adhesion signal. FN30-8 could not bind this fragment but did recognize a longer cell-binding fragment containing additional greater than 111 amino acid residues upstream of the 11.5-kDa fragment. Since the RGD-dependent cell adhesion seems to require another signal located at a region 50-160 residues upstream of the 11.5-kDa fragment for full activity, FN30-8 may exert its inhibitory effect by blocking the latter signal.

Amino Acids↗
PubMed1989

Magnetocardiographic studies of ventricular repolarization in old inferior myocardial infarction.

Isomagnetic maps of 50 normal subjects (control group) and 23 patients with old inferior myocardial infarction (IMI group) were recorded in order to analyse T wave abnormalities in inferior myocardial infarction. The T wave of the magnetocardiogram (MCG) in the control group showed negative deflections in the left upper portion and positive deflections in the right lower portion, thus resulting in a T vector directed leftward and inferiorly. The T wave of the IMI group was flat or positive in the left upper portion and flat or negative in the right lower portion, suggesting a T vector directed superiorly. In addition, opposing dipoles were observed in 36.4% of the IMI group; i.e. one directed superiorly, presumably due to inferior myocardial ischaemia, and the other directed inferiorly due to normal repolarization. Localized T vector abnormalities could be detected by the MCG in some cases, in which coronary T waves of the standard electrocardiogram had returned to normal. Furthermore, multiple dipoles were more frequently observed in the isomagnetic map than in the isopotential map (5 vs. 15; P less than 0.01). These results suggest that the MCG is helpful in diagnosing myocardial ischaemia when this is not detectable on the electrocardiogram.

Adult↗
PubMed1989

Adenosine potentiates neurally- and histamine-induced contraction of canine airway smooth muscle.

We studied the effect of adenosine on airway reactivity of isolated canine bronchial smooth muscle under isometric conditions in vitro. Administration of adenosine and its analogs increased the contractile responses of bronchial segments to electrical field stimulation in a dose-dependent fashion, where the rank order potency was N-ethylcarboxamideadenosine greater than adenosine greater than N-cyclohexyladenosine, but had no effect on those to exogenous acetylcholine. This potentiation was more pronounced at relatively low than at high stimulus frequencies, the maximal increase from the baseline responses being 56.3 +/- 9.6% at 1 Hz (mean +/- SE, p less than 0.01). Adenosine also increased the histamine-induced contraction causing a leftward shift of the histamine dose-response curves, an effect that was abolished in the presence of atropine. These results suggest that adenosine potentiates airway responsiveness to vagal stimulation and to histamine through the activation of prejunctional A2 receptor, probably involving the accelerated release of acetylcholine from the cholinergic nerve terminals.

Acetylcholine↗
PubMed1989

Structural changes in airways of rats exposed to nitrogen dioxide intermittently for seven days. Comparison between major bronchi and terminal bronchioles.

Structural changes caused by exposure to NO2 were compared between the largest intrapulmonary bronchi (major bronchi) and the terminal bronchioles. Rats were exposed to 50 ppm NO2 for 5 h a day for 7 consecutive days, and microscopic findings were assessed subjectively and quantitatively. Destruction of airway epithelium was present on Day 1, and the reparative phase was observed between Days 3 and 7. Light microscopy showed that on Day 1, loss of cilia and disintegration of epithelium occurred, and that the latter was worse in major bronchi than in terminal bronchioles; apical projections of Clara cells in terminal bronchioles were lost almost totally. Recovery of epithelium began by Day 3 and cilia by Day 5, and ciliogenesis progressed less promptly in terminal bronchioles. Clara cells did not return to normal during the experiment. Furthermore, a decrease in the airway diameter occurred in peripheral airways along with an increase in mural thickness in terminal bronchioles. Mural inflammation was also seen more conspicuously in terminal bronchioles. Electron microscopy revealed that epithelial cells lost secretory granules on Day 1 and began to repair them by Day 5 in major bronchi and by Day 7 in terminal bronchioles. It is likely that epithelium in terminal bronchioles is not particularly sensitive to NO2 compared with that in major bronchi, but that recovery occurs more promptly in major bronchi than in terminal bronchioles. Mechanisms underlying bronchoconstriction occurring preferentially in peripheral airways are also discussed.

Animals↗
PubMed1989

[A case of myelolipoma originating from bilateral adrenal glands; a comparison of CT and pathological findings].

We experienced a case of bilateral retroperitoneal tumor incidentally on CT which was carried out on suspicion of either cholelithiasis or choledocholithiasis. In company with other radiologic studies, US, angiography etc. we were able to make a correct diagnosis of adrenal myelolipoma preoperatively. Among these studies, CT coincided well with the structure of pathological findings and is thus the most powerful method for the diagnosis of myelolipoma. The case was discussed in addition to the studies of other literatures.

Adrenal Gland Neoplasms↗
PubMed1989

[Pharmacokinetic and clinical studies on cefmenoxime in neonates and infants].

Pharmacokinetic and clinical studies on cefmenoxime (CMX) in neonates and infants were conducted. 1. CMX 20 mg/kg was administered by intravenous bolus injection to 6 neonates (with ages 2 to 20 days) and 5 infants (with ages 36 to 107 days) and its serum concentration and urinary excretion rates were determined. In the neonates, serum concentrations of CMX after intravenous administration reached peak levels of 48.2 to 90.7 micrograms/ml (mean 70.4 +/- 14.3 micrograms/ml) in 1/4 hour, then declined with half-lives of 1.27 to 5.19 hours (mean 2.28 +/- 1.56 hours), and were 3.6 to 16.9 micrograms/ml (mean 8.3 +/- 6.0 micrograms/ml) at 6 hours. In the infants, serum concentrations at 1/4 hour were 67.5 to 111.0 micrograms/ml (mean 95.5 +/- 18.0 micrograms/ml); half-lives were 0.64 to 0.94 hour (mean 0.81 +/- 0.13 hour); and the serum concentrations at 6 hours were 0.2 to 1.1 micrograms/ml (mean 0.7 +/- 0.4 micrograms/ml). Mean peak serum concentrations in the neonates tended to be lower than those in the infants, but higher than those in children. Regarding the age differences of serum concentrations due to age in the neonates, their peak levels tended to be lower in younger ones. Half-lives were shorter in older subjects and, in early infancy, approached values observed in children. Urinary recovery rates in the first 6 hours after intravenous administration ranged from 43.6 to 87.5% (mean 61.6 +/- 14.6%) in the neonates and from 52.1 to 90.8% (mean 78.0 +/- 15.1%) in the infants. Thus, recovery rates were high even in younger subjects and tended to be higher in older subjects. 2. CMX was administered to 27 neonates and 4 infants to investigate its clinical effect, bacteriological effect and side effects. Clinical efficacy ratings of the drug in 19 neonate cases that could be evaluated (1 with purulent meningitis, 2 with suspected septicemia, 1 with acute bronchitis, 12 with acute pneumonia, 1 with impetigo, 1 with periumbilical abscess and 1 with acute pyelonephritis) were "excellent" in 14 cases, "good" in 4, and "poor" in 1. The efficacy rate covering "excellent" and "good" was 94.7%. In 4 infants (2 with acute pneumonia, 1 with periumbilical abscess and 1 with acute pyelonephritis), "excellent" was obtained in 2 cases and "good" in 2 cases. Thus, all the cases showed "good" or higher ratings. Bacteriologically, 1 strain of Staphylococcus aureus and 3 strains of Escherichia coli in neonates were eradicated while, in infants, 1 strain of S. aureus persisted but 1 of E. coli was eradicated.(ABSTRACT TRUNCATED AT 400 WORDS)

Alanine Transaminase↗