PubMed Health⌕ Search

Biomedical subjects

M Sumida

Publications and source records attributed to M Sumida.

At least 127 records · Page 7Linked to original sources
PubMed1985

Studies on the adenylate kinase isozymes from the serum and erythrocyte of normal and Duchenne dystrophic patients. Isolation, physicochemical properties, and several comparisons with the Duchenne dystrophic aberrant enzyme.

Two species of adenylate kinase isozymes (ATP:AMP phosphotransferase, EC 2.7.4.3) from human Duchenne dystrophic serum were separated by Blue Sepharose CL-6B affinity column chromatography. One of these species was the "aberrant" adenylate kinase isozyme, found specifically in the Duchenne type of this disease (Hamada, M., Okuda, H., Oka, K., Watanabe, T., Ueda, K., Nojima, M., Kuby, S.A., Manship, M., Tyler, F., and Ziter, F. (1981) Biochim. Biophys. Acta 660, 227-237). The separated aberrant form possessed a molecular size of 98,000 (+/- 1,500), whereas the normal serum species of the enzyme was 87,000 (+/- 1,600) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, by gel filtration, and by sedimentation equilibrium. The sedimentation coefficient of each species was found to be 5.8 S for the aberrant form and 5.6 S for the normal form, respectively. The subunit size (Mr = 24,700) of the aberrant enzyme in 8 M urea proved to be very similar to that of the normal human liver enzyme (Hamada, M., Sumida, M., Okuda, H., Watanabe, T., Nojima, M., and Kuby, S.A. (1982) J. Biol. Chem. 257, 13120-13128), and the normal species subunit (Mr = 21,700) was found to be very similar to that of the normal human muscle enzyme (Kuby, S.A., Fleming, G., Frischat, A., Cress, M.C., and Hamada, M. (1983) J. Biol. Chem. 258, 1901-1907). Both species were tetrameric enzymes in the serum. The amino acid composition for the normal species was similar to that for the muscle-type enzyme, and that for the aberrant species was similar to the liver enzyme, but with some notable exceptions in both cases. Thus, the normal species had no tryptophan and two half-cystine residues/subunit; whereas, there was 1 tryptophan and 4 half-cystine residues/subunit of the aberrant molecule. The amino acid composition of both serum isozymes when compared to their respective muscle or liver-type enzyme differed mainly in the content of Glu, Asp, His, Leu, Ile, Gly. Kinetic properties of the two forms of human serum adenylate kinase were studied at limiting concentrations of both ADP3- and MgADP- in the reverse reaction and of AMP2- and MgATP2- in the forward reaction. The type of reaction mechanism compatible with the data was a two-substrate random quasiequilibrium type of mechanism without independent binding of the substrates and with a rate-limiting step largely at the interconversion of the ternary complexes.

Adenylyl Cyclases↗
PubMed1985

Incidence of portal vein thrombosis in liver cirrhosis. An angiographic study in 708 patients.

Portal vein thrombosis was thought to be a common complication of liver cirrhosis in the past. The incidence of angiographically demonstrable portal vein thrombosis was studied in 708 consecutive patients with unequivocal cirrhosis seen in the past 10 yr in whom either transhepatic portography or superior mesenteric arterial portography clearly delineated the major portal vein system. Excluding 2 cases that were thought to be associated with past splenectomy, there were 4 cases of portal vein thrombosis related to cirrhosis, all in a decompensated stage. The calculated incidence of portal vein thrombosis was 0.573% of all cirrhotic patients without splenectomy in the past. They constituted 23.5% of the 17 cases of extrahepatic portal vein obstruction encountered during the same period. There were 78 cases of idiopathic portal hypertension similarly studied angiographically, and the incidence of portal vein thrombosis unrelated to splenectomy was 2.86%. A statistical survey based on 247,728 necropsies recorded in the Japan Autopsy Registries of 1975-1982 showed a 0.05489% incidence of portal vein thrombosis and a 6.58857% incidence of cirrhosis of all types among them, suggesting that portal vein thrombosis is not a common complication of cirrhosis in Japan in recent years.

Adult↗
PubMed1984

Ca2+,Mg2+-ATPase of microsomal membranes from bovine aortic smooth muscle. Identification and characterization of an acid-stable phosphorylated intermediate of the Ca2+,Mg2+-ATPase.

An acid-stable phosphoprotein was formed in a microsomal membrane fraction isolated from bovine aortic smooth muscle in the presence of Mg2+ + ATP and Ca2+. The microsomes also showed Ca2+ uptake activity. The Ca2+ dependence of phosphoprotein formation and of Ca2+ uptake occurred over the same range of Ca2+ concentration (1-10 microM), and resembled similar findings from rabbit skeletal microsomes. The molecular weight of the phosphorylated protein, estimated by SDS-gel electrophoresis, was approximately 105,000. The phosphoprotein was labile at alkaline pH, and its decomposition was accelerated by hydroxylamine. Half-maximum incorporation of 32P in the presence of 10 microM Ca2+ occurred at 60 nM ATP. The calcium-dependent phosphoprotein formation was not affected by 5 mM NaN3, but was inhibited in a dose-dependent fashion by ADP with a 50% inhibition occurring at 180 microM. Fifty mM MgCl2 was required for the maximal phosphorylation. The rate of phosphoprotein decomposition after adding 2 mM EGTA was accelerated by varying the Mg2+ concentration from 10 microM to 3 mM. Alkaline pH (9.0) slowed the rate of phosphoprotein decay. Optimal Ca2+-dependent phosphoprotein occurred at 15 degrees C over a broad pH range (6.4 to 9.0). The activation energy of EGTA-induced phosphoprotein decomposition was 25.6 kcal/mol between 0 and 16 degrees C and 14.6 kcal/mol between 16 and 30 degrees C. The phosphoprotein formed by aortic microsomes was thus quite similar to the acid-stable phosphorylated intermediate of the Ca2+-transport ATPase of sarcoplasmic reticulum from skeletal and cardiac muscle. These data suggest that the Ca2+-dependent phosphoprotein is a reaction intermediate of the Ca2+,Mg2+-ATPase of the aortic microsomes.

Adenosine Diphosphate↗
PubMed1983

Role of endogenous lipid droplets of fat cells in epinephrine-induced lipolysis.

Endogenous lipid droplets were prepared by subjecting fat cells to hypotonic shock and to Triton X-100 treatment. The structure of the endogenous lipid droplet fraction was examined by scanning and transmission electron microscopies. Neither intact fat cells nor disrupted cell membranes were detectable in the endogenous lipid droplet fraction. With this endogenous substrate, epinephrine elicited lipolysis with either hormone-sensitive lipase or lipoprotein lipase, but no cyclic AMP-protein kinase mediated stimulation of lipolysis was observed. On the other hand, epinephrine did not stimulate lipolysis when triolein emulsified with arabic gum was used as substrate. With the latter exogenous substrate, however, cyclic AMP-protein kinase was found to stimulate lipolysis with hormone-sensitive lipase as enzyme. These results agree with the proposal of Wise and Jungas that the epinephrine-stimulated increase of hydrolysis of endogenous fat is not mediated through cyclic AMP-protein kinase. A possible mechanism of hydrolysis of endogenous fat by induction of lipolysis by epinephrine in fat cells is discussed.

Adipose Tissue↗
PubMed1983

Stress analysis of pertrochanteric fractures with different fixation devices--behavior under muscle forces and vertical static loading.

The author examined the stress analysis with the strain measuring method on femoral models. We applied static loading with the muscle forces on the frontal plane in a one-legged stance. The results showed that the distribution of the stresses on the surface of the fractured femur revealed an extreme change--"protection phenomenon" at the fracture site in the nail plate group more than in the Ender nails. This may indicate the main transition of the bending force through the devices, resulting in fatigue fracture or breakage of the devices clinically.

Biomechanical Phenomena↗
PubMed1983

[Problems of early diagnosis of pancreatic cancer and evaluation of various morphological studies].

Clinical symptoms and abnormality of laboratory examinations in 62 patients with proven pancreatic carcinoma were studied. The following indications for detailed examination of the pancreas have been evolved: (1) vague abdominal symptoms, (2) jaundice, (3) abnormalities of laporatory examinations including serum LAP, ALP, amylase and cholinesterase level, and abnormal GTT. In the jaundiced patient the initial examination is US followed by PTCD to relieve the jaundice, and then angiography to assess resectability of the tumor. In the non-jaundiced patient US is used as a screening procedure. Should this be abnormal a lesion may be confirmed by CT. If not ERCP is indicated when there is some distinct reason to suspect pancreatic disease. If ERCP reveals abnormality then angiography is performed to determine whether the lesion is benign or malignant, and if malignant it is resectable or not. In the period of 1968 and 1981, 112 proven pancreatic carcinomas were studied. Overall resectability was 26%. Thirty tumors were less than 3 cm and the smallest lesion measured 1.2 cm.

Angiography↗
PubMed1982

The effect of pH on the transient-state kinetics of Ca2+-Mg2+-ATPase of cardiac sarcoplasmic reticulum. A comparison with skeletal sarcoplasmic reticulum.

The effect of pH on the Ca2+-Mg2+-dependent ATPase of sarcoplasmic reticulum (SR) was investigated with a rapid mixing quench-flow apparatus capable of measuring phosphorylation and dephosphorylation at times as rapid as 4 msec. The rates of formation and decomposition of the phosphorylated intermediate (E approximately P) of the Ca2+-Mg2+-ATPase were studied in the pH range between 7.6 and 6.0. At pH 6.8, the rates of formation of the phosphorylated intermediate of the Ca2+-Mg2+-ATPase of sarcoplasmic reticulum are the same (t1/2 = 10 msec) for cardiac and skeletal sarcoplasmic reticulum preloaded with calcium, but decrease as the pH is lowered. The effect of acid pH (6.0) is more pronounced for cardiac sarcoplasmic reticulum (t 1/2 = 47 msec) than for skeletal sarcoplasmic reticulum (t 1/2 = 17 msec), in agreement with studies showing that acidosis has a more pronounced effect on cardiac muscle than on skeletal muscle. In addition, a decrease in pH results in a decrease in the rate of the E approximately P decomposition step (the slowest step in the SR reaction sequence). The E approximately P decomposition half-lives were observed to be 97 and 77 msec, respectively for cardiac and skeletal SR at pH 6.8. At pH 6.0, the half-lives were increased to 136 and 178 msec for cardiac and skeletal SR, respectively.

Adenosine Triphosphatases↗
PubMed1981

Chromosome 14q+ in adult T-cell leukemia.

Cytogenetic studies were performed on leukemic cells from two patients with adult T-cell leukemia. A 14q+ marker chromosome was found in the peripheral blood leukocytes from patient No. 1 and in a leukemic T-cell line (MT-1) derived from the peripheral blood of patient No. 2. The 14q+ resulted from a t(12;14) in patient No. 1 and from a t(Y;14) in patient No. 2 with a break point at 14q32 in each case. In addition, the leukemic cells from patient No. 1 showed a t(1;7) and a 9q-, while the MT-1 line had numerous structural abnormalities. Thus, it is clear that a 14q+ translocation is not restricted to B-cell neoplasms but occurs in T-cell neoplasms as well.

Adult↗