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Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 955 records · Page 53Linked to original sources
PubMed1983

The effect of heart and skeletal muscle troponin complexes and calmodulin on the Ca2+-dependent reactions of phosphorylase kinase isoenzymes.

The dephosphorylated form of phosphorylase kinase was purified 700-fold from rabbit heart extract. The purified enzyme had a pH 6.8/pH 8.2 activity ratio of 0.04-0.08 and was completely dependent on Ca2+ with an apparent Ka value for Ca2+ of 2.59 microM at pH 6.8. At free Ca2+ concentrations between 0.057 microM and 400 microM, 1.5 microM rabbit heart troponin complex had no significant effect on the reaction. However, 1.5 microM rabbit skeletal muscle troponin complex stimulated the reaction 1.5-2-fold with a concomitant decrease in the Ka value for Ca2+ to 1.40 microM. No differences in the effects of these troponin complexes were observed when heart-type and skeletal muscle-type phosphorylase b isoenzymes from either rabbit or pig were used as substrate. Similar effects of heart and skeletal muscle troponin complexes were observed on the Ca2+-dependent reaction of the dephosphorylated form of phosphorylase kinase partially purified from rabbit skeletal muscle. A saturating concentration (1.36 microM) of bovine brain calmodulin stimulated 2-5-fold the Ca2+-dependent reaction of skeletal muscle phosphorylase kinase, but not the reaction of heart phosphorylase kinase. Heart troponin complex (12 microM) suppressed 80-100% the stimulatory effect of skeletal muscle troponin complex on the reactions of phosphorylase kinase isoenzymes, but had no significant effect on the stimulation by calmodulin of skeletal muscle phosphorylase kinase reaction.

Animals↗
PubMed1983

Presence of link protein in cartilage from cmd/cmd (cartilage matrix deficiency) mice.

Immunohistochemical and biochemical evidence that the cartilage from cmd/cmd mice, who have an autosomal recessive lethal mutation causing cartilage matrix deficiency, synthesizes link protein nearly at a normal level is provided. Since cartilage-characteristic proteoglycan is not synthesized in this mutant mouse (K. Kimata, H-J. Barrach, K. S. Brown, and J. P. Pennypacker (1981) J. Biol. Chem. 256, 6961-6968), link proteins are apparently not in conventional proteoglycan aggregate. However, the link proteins are functional and able to interact with exogenous cartilage-characteristic proteoglycan monomer and hyaluronic acid to form aggregates.

Animals↗
PubMed1983

Phosphoprotein phosphatases in human erythrocyte cytosol.

More than 97% of spectrin phosphatase activity in human erythrocyte hemolysate was recovered in cytosol. The cytosolic phosphatase activity was resolved into four peaks, namely phosphatases I (22%, Mr = 180,000), II (3%, Mr = 42,000), III (8%, Mr = 177,000), and IV (62%, Mr = 104,000), by aminohexyl-Sepharose column chromatography. Although these phosphoprotein phosphatases also catalyzed the dephosphorylation of phosphorylase a, glycogen synthase b, and phosphorylated H1 and H2B histones, the phosphatases differed from each other in preferences for substrates and the Mg2+ or Mn2+ requirements for their activities. The treatment with 80% ethanol converted phosphatases I, III, and IV to Mr = 31,000 forms which had essentially the same physical and catalytic properties. By contrast, the molecular weight and catalytic properties of phosphatase II, which was Mg2+- or Mn2+-dependent, were not changed by the same ethanol treatment. The major spectrin phosphatase, phosphatase IV, was purified to near homogeneity, as judged by polyacrylamide gel electrophoresis. Sodium dodecyl sulfate-gel electrophoresis revealed that the enzyme was composed of one 32,000-Da polypeptide (alpha) and one 69,000-Da polypeptide (beta). Km values of the enzyme for phosphorylated spectrin and H2B histone were 1.63 +/- 0.45 and 48.2 +/- 7.6 microM, respectively. The spectrin phosphatase activity was stimulated about 2-fold by 5-25 mM Mg2+, but was completely inhibited by the same concentration of Mn2+. Physiological concentrations of adenine nucleotides, 2,3-diphosphoglyceric acid, cyclic nucleotides, or Ca2+ and/or calmodulin had no significant effect on the reaction, but 20 mg/ml of hemoglobin inhibited the reaction by 60%. -SH-blocking agents but not iodoacetate inhibited the reaction.

Chromatography, Gel↗
PubMed1983

Kinetics of antisecretory action of a new H2-antagonist, YM-11170, in conscious dogs.

The antisecretory property of YM-11170 was compared with that of cimetidine and atropine in the Heidenhain pouch dog. YM-11170 inhibited competitively dimaprit-induced gastric acid secretion in doses of 33 and 100 nmol/kg per h and its antisecretory potency was 148 times more pronounced than that of cimetidine. The secretory action of pentagastrin and methacholine was also inhibited by YM-11170 and cimetidine with doses similar to those required for the inhibition of dimaprit action although the inhibition by the H2-antagonists was not of the surmountable type. Atropine inhibited gastric secretion stimulated by methacholine and pentagastrin more strongly than that stimulated by dimaprit. It is concluded that YM-11170 is a competitive antagonist of dimaprit-induced gastric secretion in vivo and that the activity of the H2-antagonists in blocking gastric H2-receptors may reflect their inhibitory effect on the acid response to pentagastrin and methacholine.

Animals↗
PubMed1983

Effect of ascorbate on the contractile response induced by DMPP in guinea-pig ileal longitudinal muscle strip.

The study concerned the effect of ascorbate on the contractile response induced by DMPP in the guinea-pig ileal longitudinal muscle. At 0.5-10 mM, sodium ascorbate shifted the dose-response curve for DMPP to the left and enhanced the maximum contraction. On the other hand, in the presence of ascorbate, the high potassium (40 mM)-induced contraction was not altered, and the contraction by acetylcholine and histamine in concentrations higher than 1 microM and 0.3 microM, respectively, was slightly reduced. Thus, ascorbate enhanced the contractile response caused by DMPP which induced acetylcholine release from nerve terminals indirectly by stimulating the ganglia of the Auerbach's plexus elements. This potentiating effect of ascorbate was studied with a dual organ bath which was partitioned into two compartments. When the oral half of the muscle strip was directly stimulated by DMPP applied to the oral compartment, a contraction of the unstimulated anal part was observed. This contraction was blocked by atropine or adenosine applied to the unstimulated part. Tetrodotoxin, applied to the stimulated part, abolished the contraction of the unstimulated part. The contraction of the unstimulated part was enhanced by ascorbate applied to the stimulated part but not to the unstimulated part. These results indicate that the contraction observed in the unstimulated part may have been caused by acetylcholine release from cholinergic nerves as a result of conduction of the oral part excitation by DMPP along cholinergic nerve fibers; ascorbate may have affected the ganglion cells in Auerbach's plexus to potentiate the action of DMPP.

Acetylcholine↗
PubMed1983

Resolution and reassociation of three distinct components from pig heart phosphoprotein phosphatase.

A partially purified pig heart phosphoprotein phosphatase was dissociated into three distinct components, namely alpha, beta, and gamma, by gel filtration on Sephacryl S-200 followed by chromatography on DEAE-Sephadex in the presence of 6 M urea. Although alpha itself had phosphatase activities toward P-H2B histone, P-H1 histone, phosphorylase a, and glycogen synthase b, beta and gamma had no activity toward these substrates even in the presence of 1 mM Mn2+. The beta component (Mr = 80,000) combined with alpha (Mr = 31,000) in the absence of urea to produce Form 2 (Mr = 123,000) with concomitant increase in P-H1 histone phosphatase activity and Mg2+ requirement for P-H2B histone phosphatase activity (Imazu, M., Imaoka, T., Usui, H., Kinohara, N., and Takeda, M. (1981) J. Biochem. 90, 851-862). The gamma component (Mr = 62,000) reassociated with Form 2 to produce Form 1 (Mr = 199,000) which was similar to the original phosphoprotein phosphatase in substrate specificity and Mg2+ requirement. Binding of gamma to Form 2 strongly suppressed the phosphatase activities toward phosphorylase a and glycogen synthase b with marginal effects on the other phosphatase activities and Mg2+ requirement. However, gamma alone could not associate with alpha. The gamma component was sensitive to treatment with heat (60 degrees C for 2 min) or trypsin and was resistant to treatment with DNase or RNase. The pig heart phosphoprotein phosphatase was further purified to near homogeneity, as judged by polyacrylamide gel electrophoresis. Sodium dodecyl sulfate gel electrophoresis revealed that the purified enzyme (Mr = 171,000) was composed of three polypeptide components, namely alpha', beta', and gamma' with molecular weights of 34,000, 69,000, and 56,000, respectively. The component stoichiometry was determined to be alpha' 1 beta' 1 gamma' 1 by densitometric tracing of the Coomassie blue-stained bands on the acrylamide gel. After dissociation of alpha ' and other components by gel filtration of the purified enzyme on Sephacryl S-200 in the presence of 6 M urea, one alpha ' combined with one beta' to produce Form 2' of Mr = 106,000. Since Form 1 and the purified enzyme as well as Form 2 and Form 2' had similar catalytic properties and s20,w values, respectively, component compositions are suggested to be alpha 1 beta 1 gamma 1 for Form 1 and alpha 1 beta 1 for Form Form 2.

Animals↗
PubMed1983

The fine structure of pancreatic stones as shown by scanning electron microscopy and X-ray probe microanalyser.

To delineate the process of pancreatic stone formation, stones from four patients were studied with a scanning electron microscope and X-ray probe microanalyser. The stones consisted of a central core and surrounding shell. Two kinds of stones were demonstrated: one had a core composed of a calcium-rich amorphous substance and interlacing fibrils; the other had a core consisting of multiple cavities with smooth walls composed of a calcium-deficient amorphous substance. The shells showed a common structure: zones of layers or bands of a calcium-rich amorphous substance, network fibrils filled with a calcium-rich amorphous substance, and laminated parallelogrammic or polygonal plates of calcite parallel to the surface in one layer and oblique or perpendicular in the next layer. Calcium was in the crypto-crystalline state as well as crystalline state of calcite. Crystalline calcite showed spiral and epitaxial growth along with findings of dissolution, resembling cholesterol crystals of gall stones. Pancreatic stones are probably formed through central core formation and layered growth of a shell. Comparison of stones and protein plugs suggests that protein plugs can grow to stones with calcite deposition accompanied by precipitation of network fibrils and an amorphous substance.

Bacteria↗
PubMed1983

Antiallergic agents. 2. N-(1H-tetrazol-5-yl)-6-phenyl-2-pyridinecarboxamides.

A new series of N-(1H-tetrazol-5-yl)-6-phenyl-2-pyridinecarboxamides was prepared to determine the effects of substituents on the benzene and pyridine rings on antiallergic activity in the rat passive cutaneous anaphylaxis (PCA) assay after oral administration. One member of this series, N-(1H-tetrazol-5-yl)-4-methyl-6-[4-(methylamino)-phenyl]-2- pyridinecarboxamide (231), has an ED50 value of 0.8 mg/kg po and is 85 times more potent than disodium cromoglycate (DSCG) on intravenous administration. Further evaluation of 231 as a clinically useful antiallergic agent is in progress.

Animals↗
PubMed1983

Histochemical studies on enzyme-digested protein plugs of patients with chronic pancreatitis: a preliminary report.

Sulfated acidic mucopolysaccharides have been found to be significant components of "protein plugs" in patients with chronic pancreatitis. The precise identification of the mucopolysaccharides and their distribution within the protein plugs may clarify the pathogenesis of the plugs. Pure pancreatic juice from five patients with chronic pancreatitis was obtained by endoscopic retrograde catheterization of the papilla of Vater. Enzymes for digestion of the plugs included hyaluronidase of the bovine testes and streptomyces hyalurolyticus, chondroitinase ABC and AC, and sialidase (neuraminidase). Our study indicated that: I) Sialic acid is distributed throughout the plugs and may be a major component, followed by a lesser amount of chondroitin sulfate B. 2) Chondroitin sulfate A, C, D and E and chondroitin may be minor components. 3) Hyaluronic acid is negligible in the plugs.

Chronic Disease↗
PubMed1983

[Pre-operative endoscopic infusions of an adsorbent containing mitomycin C (MMC-CH44) in stomach cancer].

Small charcoal particles adsorbing Mitomycin C (MMC-CH) were used in the treatment of lymphnode metastasis of gastric cancer. Immediately after injection of MMC-CH into the gastric wall, lymph capillaries and regional lymphnodes were stained in black and the high concentration of MMC was delivered with charcoal particles. MMC-CH was injected preoperatively using endoscope into the gastric wall of 20 patients with gastric cancer. MMC-CH was observed in 70% of metastatic regional lymphnodes. Systemic side effect was not noted at all. Erosion and shallow ulcers were observed at the site of injection but no perforation occurred.

Adsorption↗