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M Sumida

Publications and source records attributed to M Sumida.

At least 109 records · Page 6Linked to original sources
PubMed1990

Induction of platelet Ca2+ influx and mobilization by a monoclonal antibody to CD9 antigen.

We found that a monoclonal antibody (MoAb) to CD9 antigen, PMA2, induced a rise in cytosolic free calcium concentration ([Ca2+]i) in fura-2-loaded platelets, and we examined whether this response was due to direct action of PMA2 on CD9 antigen. The rise in [Ca2+]i was dependent on the PMA2 concentration, irrespective of the presence or absence of extracellular Ca2+. The role of secreted adenosine diphosphate (ADP) and thromboxane in the [Ca2+]i response to PMA2 was studied using creatine phosphate/creatine phosphokinase (CP/CPK) and aspirin. Combined treatment with CP/CPK and aspirin abolished the rise in [Ca2+]i, although either CP/CPK or aspirin alone produced only partial inhibition. Inhibition of adenosine triphosphate (ATP) secretion and thromboxane B2 synthesis by an MoAb to the glycoprotein IIb-IIIa complex, PMA1, resulted in little [Ca2+]i response to PMA2. In contrast, thrombasthenic platelets, in which ATP secretion and thromboxane B2 synthesis were normal, showed a normal [Ca2+]i response. When PMA2 was added to CD9+ mononuclear cells, no rise in [Ca2+]i was observed. Thus, we conclude that binding of monoclonal immunoglobulin G molecules to the CD9 antigen raises [Ca2+]i through the effect of secreted ADP and thromboxane on platelets, and that CD9 antigen is not directly involved in induction of Ca2+ influx and mobilization.

Adenosine Triphosphate↗
PubMed1990

Luminol chemiluminescence reaction catalyzed by a microbial peroxidase.

A peroxidase produced by microorganisms belonging to the genera Arthromyces and Coprinus was found to be a potent catalyst for the chemiluminescent oxidation of luminol, the luminescence produced per unit of microbial peroxidase protein being well over 100 times as strong as that produced by horseradish peroxidase. No large difference in Km value for H2O2 in the presence of luminol was found between Arthromyces ramosus peroxidase and horseradish peroxidase (7.0 and 15.5 microM, respectively), but Vmax of the Arthromyces peroxidase was 500 times greater than that of the horseradish peroxidase. It was also found that the Arthromyces peroxidase surpasses, beyond expectation, the horseradish peroxidase in the initial velocity of the chemiluminescence reaction with the stopped-flow method. The Arthromyces peroxidase was used for the glucose and cholesterol assays, which were notably more sensitive than the corresponding assays involving the horseradish peroxidase.

Calibration↗
PubMed1990

Biomodulator-mediated susceptibility of endogenous lipid droplets from rat adipocytes to hormone-sensitive lipase.

The amount of fatty acid release by a fat cell homogenate without pretreatment with epinephrine was found to be slightly more than that released from fat cells by epinephrine, suggesting that fat cells contain high lipolytic activity even in the absence of lipolytic agents. Fat cells contain high hormone-sensitive lipase activity (1383 mumole free fatty acids/g/hr) in the absence of epinephrine, and addition of epinephrine to the cells did not increase the activity, significantly. Like epinephrine, DBcAMP and/or theophylline also elicited marked release of glycerol from fat cells without activating the hormone-sensitive lipase activity. However, although fat cells contain a large amount of hormone-sensitive lipase, lipolysis was negligible in the absence of these lipolytic agents. These results suggest that lipolytic agents such as epinephrine, DBcAMP, and theophylline induce lipolysis in fat cells through some mechanism other than activation of hormone-sensitive lipase and that in the absence of lipolytic agents, some system in fat cells inhibits lipolysis of endogenous lipid droplets by hormone-sensitive lipase. The lipid droplets in fat cells consist mainly of triglyceride with phospholipids, cholesterol, carbohydrate, and protein as minor constituents. The phospholipid fraction was found to consist of 75% phosphatidylcholine and 25% phosphatidylethanolamine. Of the minor constituents of endogenous lipid droplets, only phosphatidylcholine strongly inhibited hormone-sensitive lipase activity in a [3H]triolein emulsion. These results suggest that phosphatidylcholine in endogenous lipid droplets may be responsible for inhibition of hormone-sensitive lipase. Then, a cell-free system was established in which epinephrine, DBcAMP, and theophylline stimulated lipolysis of endogenous lipid droplets from fat cells by lipase solution. In this system, these lipolytic agents did not induce lipolysis in the absence of added lipase. Lipolysis in the mixture of the endogenous lipid droplets and lipase solution was accelerated by phospholipase C with concomitant loss of epinephrine-induced lipolysis. After pretreatment of the endogenous lipid droplets with phospholipase C, these lipolytic agents no longer induced lipolysis. Pretreatment of the endogenous lipid droplets with phospholipase C reduced their phospholipid content with the formation of phosphorylcholine, but did not affect their triglyceride and cholesterol contents. Treatment of the endogenous lipid droplets with phospholipase D did not affect lipolysis in the cell-free system. These results suggest that phosphatidylcholine in the endogenous lipid droplets may inhibit their lipolysis by hormone-sensitive lipase in fat cells and also be involved in the mechanisms of the stimulatory effects of epinephrine, DBcAMP, and theophylline on lipolysis.

Adipose Tissue↗
PubMed1990

Inhibitory effect of tumor necrosis factor on gene expression of hormone sensitive lipase in 3T3-L1 adipocytes.

Recombinant human tumor necrosis factor (TNF) depressed the activities of both lipoprotein lipase (LPL) and hormone sensitive lipase (HSL) in 3T3-L1 adipocytes, 3 to 24 h after its introduction to the cells. HSL gene expression, as measured by Northern blotting analysis with 32P-labeled cloned HSL-cDNA, was also suppressed. These results suggested that the reduction in HSL activity caused by TNF resulted from inhibited gene expression of the enzyme.

Adipose Tissue↗
PubMed1990

Multiforms of mammalian adenylate kinase and its monoclonal antibody against AK1.

An attempt has been made to determine the intracellular distribution of the multiforms of the adenylate kinase (AK) isoenzymes in mammalian tissues, to shed some light on their physiological roles, especially in energy metabolism. The adenylate kinase zymograms obtained from isoelectric focusing yielded two typical isoform patterns: (1) with a pI greater than or equal to 9 and 8.6, specific for bovine skeletal muscle, heart, aorta and brain, and (2) with a pI = 7.9 and 7.1, specific for liver and kidney. Pattern (1) was attributed to the cytosolic isoenzyme (AK1) as demonstrated by immunostaining with anti-AK1. Pattern (2) was attributed to the mitochondrial isoenzyme (AK2). These results were largely confirmed by chromatofocusing experiments. The AK1 isoenzyme was partially purified from the cytosol fraction of bovine aortic smooth muscle and had an apparent Mr of 23.5 kilodaltons. Its kinetic features are discussed from a comparative standpoint. Finally, the human serum AK1 isoform was also detected by Western blotting with a monoclonal antibody directed against crystalline porcine muscle AK1. These results are to form the basis of further studies on the 'aberrant' adenylate kinase isoenzyme from the serum of Duchenne muscular dystrophics.

Adenylate Kinase↗
PubMed1990

Magnetic resonance imaging of Chiari malformations.

The authors describe the features of magnetic resonance (MR) images of Chiari type I and II malformations and present four illustrative cases. Downward displacement of the posterior fossa was more pronounced with type II than type I. A variety of intracranial anomalies were associated with the Chiari type II malformation, whereas type I was mainly associated with syringomyelia and craniovertebral changes. MR imaging is useful in the diagnosis of intracranial anomalies and those situated at the craniovertebral junction, including Chiari malformations.

Adult↗
PubMed1990

[A study on the relationship of taste-sensitivity to salt-restriction in adults].

A survey of the extent of the practice of salt-restriction, duration of such salt restriction, and the ability to discriminate between different degrees of salt content, was performed in a town located in Tottori prefecture Subjects were 20 families (55 persons) where both parents and their adult children had a previous history of hypertension, 38 families (111 persons) where either or both parents had a previous history of hypertension, and 33 families (99 persons) where both parents and their adult children had no history of hypertension. Sensitivity to salt-taste and the relation between the practice of salt-restriction and sensitivity to salt-taste were analyzed. The results are summarized as follows: 1. For persons with histories of hypertension current practice of salt-restriction was significantly greater degree of preference for salt-taste was lower, and the duration of salt-restriction period was longer than those persons without a history of hypertension. 2. Families where both parents and their adult children had histories of hypertension had the highest percentage of these practicing salt-restriction and the largest representation of those who practiced it for a long duration. 3. Those who restricted salt use for a long time also showed a low preference for salt-taste. 4. The sensitivity to salt-taste was much higher in persons who had histories of hypertension than others. 5. Sensitivity to salt-taste was much higher in families where both parents and their adult children had histories of hypertension than others. 6. In families where both parents and adult children had histories of hypertension, significant relationship were observed between parents and their adult children and between husbands and wives in sensitivity to salt-taste.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[A case of arachnoid cyst in the posterior fossa with lower cranial nerve palsy].

We experienced a rare case of arachnoid cyst in the right cerebellomedullary cistern. A 59-year-old female was admitted to our clinic because of lower cranial nerve palsy (deviation of uvula to the left side, swallowing disturbance, curtain sign, hoarseness, atrophy of the right sternocleidomastoid muscle, and deviation of the tongue to the right side). MRI demonstrated a mass lesion compressed towards the medulla oblongata in the right cerebellomedullary cistern. MRI was very helpful as a diagnostic tool, since there is no bone object in the posterior fossa. Although by CT cisternography, the arachnoid cyst was thought to have a communication with the surrounding subarachnoid spaces, the cyst wall was removed because of its compressive symptoms on the lower cranial nerves. After the operation, the cyst shrank, and the clinical symptoms were reduced.

Arachnoid↗
PubMed1988

Ca2+ uptake in bovine adrenocortical microsomes: formation of phosphorylated intermediate of Ca2+ dependent ATPase.

Bovine adrenocortical microsomes were prepared and partially purified by discontinuous sucrose density gradient. Light fractions of the microsomes at the interface between 15 and 30% sucrose solution, exhibited ATP dependent Ca2+ uptake. The Ca2+ uptake was dependent on temperature and stimulated by free Ca2+ (the concentration for half maximal activation = 1.0 microM) and Mg2+. The Ca2+ uptake was inhibited by ADP but not affected by 10 mM NaN3 or 0.5 mM ouabain. Calcium release from the microsomes was accelerated by a Ca2+ ionophore, A23187, but not by a Ca2+ antagonist, diltiazem. A microsomal protein with a molecular weight of 100-110 kDa was phosphorylated by [gamma-32P]ATP in the presence of Ca2+, and the Ca2+ dependency was over the same range as the Ca2+ uptake (the concentration for half maximal activation = 3.0 microM). The phosphorylated protein (EP) was stable at acidic pH but labile at alkaline pH and sensitive to hydroxylamine. The rate of EP formation at 0 degrees C in the presence of 1 microM ATP and 10 microM Ca2+ (half time = 0.2 s) was less than that in the sarcoplasmic reticulum (SR) of rabbit skeletal muscle (half time = 0.1 s). The rate of EP decomposition at 0 degrees C after adding EGTA was about 6.7 times slower (rate constant: kd = 4.3 X 10(-3) s-1) than that of SR. It was suggested that adrenocortical microsomes contain a Ca2+ dependent ATPase which function as a Ca2+ pump with similar properties to that of SR.

Adenosine Diphosphate↗
PubMed1988

[A case of chronic adult T-cell leukemia benefited by small doses of MEPP].

A 59-year-old man diagnosed as a chronic ATL with cutaneous invasion, was treated with small doses of CPM, ADM, VDS and PSL regimens according to CHOP. The treatment was successful and achieved PR at the first stage of the therapy, but it became refractory later. He was then treated with small MEPP (MXT, VP-16, CDDP and PSL) as the salvage therapy for non-Hodgkin's lymphoma. This case suggested that small MEPP might be a useful combination chemotherapy for ATL.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Structure and function of adenylate kinase isozymes in normal humans and muscular dystrophy patients.

Two isozymes of adenylate kinase from human Duchenne muscular dystrophy serum, one of which was an aberrant form specific to DMD patients, were separated by Blue Sepharose CL-6B affinity chromatography. The separated aberrant form possessed a molecular weight of 98,000 +/- 1,500, whereas the normal serum isozyme had a weight of 87,000 +/- 1,600, as determined by SDS-polyacrylamide gel electrophoresis, gel filtration, and sedimentation equilibrium. The sedimentation coefficients were 5.8 S and 5.6 S for the aberrant form and the normal form, respectively. Both serum isozymes are tetramers. The subunit size of the aberrant isozyme (Mr = 24,700) was very similar to that of the normal human liver isozyme, and the subunit size of the normal isozyme (Mr = 21,700) was very similar to that of the normal human muscle enzyme. The amino acid composition of the normal serum isozyme was similar to that of the muscle-type enzyme, and that of the aberrant isozyme was similar to that of the liver enzyme, with some exceptions in both cases.

Adenylate Kinase↗
PubMed1986

Lipoprotein biosynthesis in the larvae of the tobacco hornworm, Manduca sexta.

Lipoprotein biosynthesis in larvae of the tobacco hornworm (Manduca sexta) was investigated. By immunoblotting, it was shown that the apoproteins are present in the fat body, but not in the midgut. Fat body incubated in vitro with [35S]methionine secreted labeled apoproteins. However, when the density of the secreted particle was determined, it was found at 1.24-1.28 g/ml instead of 1.15 g/ml, which is the density of the circulating lipoprotein. Lipid analysis of immunoprecipitated lipoprotein secreted by the fat body showed a phospholipid/diacylglycerol ratio of 8.3 rather than 0.9, the ratio found in the circulating lipoprotein. When labeled oleic acid or triolein was fed to larvae, it was found that greater than 98% of the label in the circulating lipoprotein was in diacylglycerol. In studies using animals raised on a fat-free diet, it was shown that the circulating lipoprotein has properties comparable to those of the material secreted in vitro by the fat body and that this diacylglycerol-poor particle can be converted to the normal lipoprotein by feeding a bolus of triolein. These data support the hypothesis that the fat body makes and secretes a "nascent" lipoprotein which contains apoproteins and phospholipid, but is devoid of diacylglycerol. The diacylglycerol is then picked up from the midgut to complete assembly of the mature circulating lipoprotein.

Animals↗
PubMed1986

Ca2+,Mg2+-ATPase of microsomal membranes from bovine aortic smooth muscle: effects of Sr2+ and Cd2+ on Ca2+ uptake and formation of the phosphorylated intermediate of the Ca2+,Mg2+-ATPase.

The effects of various divalent cations on the Ca2+ uptake by microsomes from bovine aortic smooth muscle were studied. High concentrations (1 mM) of Co2+, Zn2+, Mn2+, Fe2+, and Ni2+ inhibited neither the Ca2+ uptake by the microsomes nor the formation of the phosphorylated intermediate (E approximately P) of the Ca2+,Mg2+-ATPase of the microsomes. The cadmium ion, however, inhibited both the Ca2+ uptake and the E approximately P formation by the microsomes. Dixon plot analysis indicated Cd2+ inhibited (Ki = 135 microM) the Ca2+ dependent E approximately P formation in a non-competitive manner. The inhibitory effect of Cd2+ was lessened by cysteine or dithiothreitol. The strontium ion inhibited the Ca2+ uptake competitively, while the E approximately P formation increased on the addition of Sr2+ at low Ca2+ concentrations. At a low Ca2+ concentration (1 microM), Sr2+ was taken up by the aortic microsomes in the presence of 1 mM ATP. It is thus suggested that Sr2+ replaces Ca2+ at the Ca2+ binding site on the ATPase.

Animals↗
PubMed1986

Accuracy of angiography in the diagnosis of small hepatocellular carcinoma.

Conventional hepatic arteriography combined with superselective infusion arteriography was carried out in 51 patients with hepatocellular carcinoma smaller than 5 cm, and angiograms of varying phases were analyzed. In cancers smaller than 40 mm, particularly in those smaller than 20 mm, so-called tumor stain in the capillary phase was the only abnormality seen in most but not all cases. Within a tumor stain, there were unstained areas in most cases and histologic examination in resected specimens showed them to be due to either necrosis, fibrosis, or fatty changes. Homogeneity and shape of the stain seemed to be related to growth speed and invasiveness of the cancer. Although overall diagnostic value of angiography for small hepatocellular carcinoma was high, super-superselective infusion hepatic arteriography produced nodular stains in 7 of 11 control cases of nonalcoholic cirrhosis without cancer, making difficult the differential diagnosis between stains due to tumors and those due to hyperplastic nodules of cirrhosis.

Adult↗