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Biomedical subjects

K Matsuda

Publications and source records attributed to K Matsuda.

At least 649 records · Page 36Linked to original sources
PubMed1986

Electrophoretic analysis of the multiple forms of dextransucrase from Leuconostoc mesenteroides.

Multiple forms of the extracellular dextransucrase [EC 2.4.1.5] from Leuconostoc mesenteroides NRRL B-512F strain were characterized by polyacrylamide gel electrophoresis. Based on the Rm (Relative mobility) values, a newly devised simple plot of log (Rm X 10/(1-Rm)) vs. degree of association of the enzyme showed a good correlation with the results obtained by the Hedrick-Smith method. Both results indicated that the B-512F dextransucrase aggregates were a mixture of two types of forms, i.e., oligomers of a 65 kDa protomer and their charge isomers. Boiling and treatment of the enzyme at pH 10.5 suggested that enzyme aggregates contained dextran or its fragments bound to the enzyme and the enzyme-dextran complex showed the charge isomerism. Since the highly aggregated forms showed higher activity for dextran synthesis than the dissociated forms, the endogenous dextran may serve as a source of primer and may stabilize the enzyme molecule. Besides allosteric regulation of the activity, the occurrence of oligomeric forms of the enzyme may play an important role in the control of dextran synthesis in vivo.

Chromatography, Gel↗
PubMed1986

Characteristics of ethacrynic acid highly sensitive Mg2+-ATPase in microsomal fractions of the rat brain: functional molecular size, inhibition by SITS and stimulation by Cl-.

Studies were performed to characterize ethacrynic acid (EA) highly sensitive Mg2+-ATPase isolated from microsomal fractions of the rat brain. The functional molecular sizes of the EA highly sensitive and EA less sensitive Mg2+-ATPases, estimated by a radiation inactivation method, were 480 and 80 kDa, respectively. An anion transport inhibitor, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) inhibited the EA highly sensitive Mg2+-ATPase activity. The type of inhibition was uncompetitive with respect to ATP, and the inhibition was suppressed by anions such as Cl-, Br- and I-. Chloride ions stimulated enzyme activity with an increase in Vmax, but not in Km, for ATP. Anions tested also increased the enzyme activity in the following order of decreasing potency: Cl- greater than Br- greater than CH3COO- = I- greater than SO4(2-) = HCO3- greater than SO3(2-). These results suggest that EA highly sensitive Mg2+-ATPase is a relatively large molecule with anion-sensitive sites that affect the ATP hydrolyzing activity and the SITS binding capacity through anions, with Cl- being the most potent.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1986

[Production of enzymes and enzyme inhibitors in neoplastic tissues].

The mechanisms of ectopic enzyme and enzyme inhibitor-production in neoplastic tissues were investigated. No evidence was obtained to suggest any difference in the structural genes of amylase-producing tumors and normal lymphocytes. mRNA sequence coding for amylase precursor in tumor tissues was identical to that of salivary amylase, suggesting that the amylase in amylase-producing tumors was identical to, or closely resembled the amylase in salivary gland. High incidence of elevation of serum pancreatic secretory trypsin inhibitor (PSTI) was observed in patients with various malignant tumors. PSTI-positive malignant cells were also frequently found in malignant tissues. A comparison of human PSTI mRNA sequence with mouse epidermal growth factor (EGF) mRNA sequence showed that they were 46% homologous. Human PSTI stimulated [3H]thymidine incorporation into DNA in human fibroblasts at concentrations present in human serum.

Amylases↗
PubMed1986

[A case of multiple cerebellar hemangioblastomas with congenital deafness, juvenile diabetes mellitus and retinal angioma].

It has already been noted that hemangioblastoma is occasionally complicated with various diseases, especially retinal angioma, cysts of kidney and/or pancreas, vascular disorders, and furthermore about 10% of hemangioblastoma are multiple. The authors report here a case of multiple cerebellar hemangioblastomas accompanied with congenital deafness, juvenile diabetes mellitus and retinal angioma. The patient, a 38-year-old man who complained of disturbance of consciousness, headache and vomiting, admitted to our hospital on October 6, 1982. He was born in consanguineous marriage family and his elder sister was also suffered from congenital deafness and juvenile diabetes mellitus, but no angiomas. CT and angiography showed a left side cystic and a right side small cerebellar lesions with remarkable ventricular enlargement. Ventriculo-peritoneal shunt and suboccipital craniectomy & removal of the tumors were performed on October 6, and November 8, 1982 succeedingly. From a point of view of hereditary occurrence, the authors investigated these complicated lesions recognized in this patient. It revealed that this case did not belong to any other categories of hereditary syndromes which were already reported and so authors considered that this was an extremely rare condition. Moreover, in case of multiple hemangiomas, cerebral angiography could be a more useful method than CT scan to detect multiplicity of the lesions in the posterior fossa.

Adult↗
PubMed1986

[Application of renal subcapsular assay to rat malignant brain tumor].

As a rapid screening method for testing chemotherapeutic agents against human tumor explants, renal subcapsular assay has been established by Bogden et al (1978). The authors investigated the effectiveness of the technique of Bogden for rat glioma. Preselected 1 mm3 fragments of viable tumor tissue of rat (CDF) were implanted under the renal capsule of normal immunocompetent rats. Then initial and final tumor sizes (formula; see text) were measured in situ with an oculometer inserted into a surgical microscope, and evaluated the changes of tumor sizes. The experiments were divided into three groups. The first group was that tumor pieces of rat (CDF) were implanted under the renal capsule of the syngenetic rats (CDF). Non-irradiated and preirradiated (400 rad) heterogenetic rats (Wistar) were used as the second and third groups. The explanted tumor pieces grew rapidly in the first group (syngenetic rats). On the other hand, poor growth of the second group (non-irradiated heterogenetic rats) was seen within 7 days after implantation, and rejected completely until 15 days after implantation. Explanted tumor pieces in the third group (pre-irradiated heterogenetic rats), however, grew enough big, though the change of tumor sizes was less than that of the first group. Histological examination was also performed. In the first and third group, proliferation of glioma cells was remarkable under the renal capsule, and neovascularization in the explanted tumor tissue was provided from the capsule, first, and then parenchym of the kidney. Even necrosis and hemorrhage were seen in the tumor tissue 15 days after implantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗