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Biomedical subjects

H Murakami

Publications and source records attributed to H Murakami.

At least 577 records · Page 32Linked to original sources
PubMed1990

Frontiers in mammalian cell culture.

For the past 60 years, fundamental discoveries in eukaryotic biology using mammalian cell cultures have been significant but modest relative to the enormous potential. Combined with advances in technologies of cell and molecular biology, mammalian cell culture technology is becoming a major, if not essential tool, for fundamental discovery in eukaryotic biology. Reconstruction of the milieu for cells has progressed from simple salt solutions supporting brief survival of tissues outside the body to synthesis of the complete set of structurally defined nutrients, hormones and elements of the extracellular matrix needed to reconstruct complex tissues from cells. The isolation of specific cell types in completely defined environments reveals the true complexity of the mammalian cell and its environment as a dynamic interactive physiological unit. Cell cultures provide the tool for detection and dissection of the mechanism of action of cellular regulators and the genes that determine individual aspects of cell behavior. The technology underpins advances in virology, somatic cell genetics, endocrinology, carcinogenesis, toxicology, pharmacology, hematopoiesis and immunology, and is becoming a major tool in developmental biology, complex tissue physiology and production of unique mammalian cell-derived biologicals in industry.

Allergy and Immunology↗
PubMed1990

Establishment of a macrophagelike cell line derived from U-937, human histiocytic lymphoma, grown serum-free.

A human macrophagelike cell line which grows in serum-free medium was established from a histiocytic lymphoma cell line, U-937. U-937 cells failed to differentiate into macrophagelike cells in serum-free medium plus 12-O-tetradecanoyl phorbol 13-acetate (TPA). Fibronectin and albumin in serum were necessary for differentiation of U-937 cells into macrophagelike cells in enriched RDF medium supplemented with insulin, transferrin, ethanolamine, selenite, egg yolk lipoprotein (eRDF-ITESL medium). The established cell line exhibited several characteristic properties of macrophage such as nitroblue tetrazolium reduction, phagocytic and alpha-naphthylbutyrate-esterase activities, and tumor necrosis factor and interleukin 1 production. At present the cells have been continuously maintained in eRDF-ITESL medium through over 150 passages.

Blood↗
PubMed1990

Dissolution mechanism of zinc phosphate dental cement in acetic and lactic acid buffers.

When zinc phosphate cement was immersed in 0.1 M acetic and lactic acid buffer solutions adjusted to pH 4.1, its dissolution rate was determined by chemical analysis. The eroded surface of the cement was examined by X-ray diffraction and SEM observation. The dissolution process of the cement immersed in the acetic acid buffer solution was mainly controlled by the diffusion of releasing species through the cement matrix and that of the cement immersed in the lactic acid buffer solution by the decomposition of the cement matrix at the surface.

Acetates↗
PubMed1990

Expression of bovine cytochrome P450c21 and its fused enzymes with yeast NADPH-cytochrome P450 reductase in Saccharomyces cerevisiae.

Recombinant plasmids for expression of bovine cytochrome P450c21 (pA gamma 2), both P450c21 and yeast NADPH-cytochrome P450 reductase (pAR gamma 1), P450c21/yeast reductase fused enzymes (pAF gamma R1, pAF gamma R2, and pAF gamma R20), and yeast reductase/P450c21 fused enzymes (pAFR gamma 1 and pAFR gamma 2) were constructed by using expression vector pAAH5. The plasmids were each introduced into the yeast Saccharomyces cerevisiae AH22 cells. The recombinant yeast strains AH22/pA gamma 2 (Y21) and AH22/pAR gamma 1 (Y21R) produced 2-3 X 10(3) molecules of P450c21 per cell. The cultures of both strains converted progesterone and 17 alpha-hydroxyprogesterone into 11-deoxycorticosterone and 11-deoxycortisol, respectively. The 21-hydroxylase activity per cell of the strain Y21R was about three times higher than that of the strain Y21, probably due to overproduction of yeast reductase. The recombinant yeast strains AH22/pAF gamma R1 (Y21RF1), AH22/pAF gamma R2 (Y21RF2), and AH22/pAF gamma R20 (Y21RF20) produced about 1.1-2.0 X 10(4) molecules per cell of the corresponding P450c21/yeast reductase fused enzymes. The specific 21-hydroxylase activity toward 17 alpha-hydroxyprogesterone per cell of the strains Y21RF1, Y21RF2, and Y21RF20 was about 21, 28, and 49 times higher than that of the strain Y21, respectively. Thus, the fused enzymes were superior to P450c21 in the specific activity and in the expression level in the yeast. The Km values for 17 alpha-hydroxyprogesterone of P450c21 in the strains Y21 and Y21R, and of the fused enzymes in the strains Y21RF1 and Y21RF2 were 0.29, 0.30, 0.67, and 0.65 microM, respectively. The Vmax values of P450c21 in the strains Y21 and Y21R, and of the fused enzymes in the strains Y21RF1 and Y21RF2 were 28, 124, 151, and 222 moles/min.mole P450c21 or fused enzyme, respectively. These results indicated that the fused enzymes showed lower affinity for the substrate, probably due to structural modification and higher reaction rates through efficient intramolecular electron transfer as compared with those of P450c21. While the strain AH22/pAFR gamma 2 (YR21F2) produced about 3 X 10(4) molecules per cell of the reductase/P450c21 fused enzyme, the specific 21-hydroxylase activity of the fused enzyme toward 17 alpha-hydroxyprogesterone was extremely low, suggesting that the structure of the fused enzyme might not be suited for electron transfer in yeast microsomes.

17-alpha-Hydroxyprogesterone↗
PubMed1990

Expression of cloned yeast NADPH-cytochrome P450 reductase gene in Saccharomyces cerevisiae.

The NADPH-cytochrome P450 reductase gene isolated from the yeast Saccharomyces cerevisiae [Yabusaki et al., J. Biochem. 103, 1004-1010 (1988)] was expressed on a multi-copy plasmid in the yeast. The transformed yeast cells with the recombinant plasmid carrying the reductase gene with a length of 3 kb produced the corresponding mRNA read from the original transcription initiation site under the control of its own promoter with a maximum length of 300 bp. The reductase content in the transformed cells was 25 times higher than that of the endogenous reductase. When the coding region for the reductase was placed between the alcohol dehydrogenase I gene promoter and the terminator of the expression vector pAAH5, the expression level was 32 times higher than at the endogenous level. These recombinant yeast strains showed enhanced cytochrome c reductase activity with increased cellular reductase levels. A simultaneous expression of yeast P450 reductase with rat P450c or bovine P450(17 alpha) resulted in 25 times or a 5 times increase in the corresponding P450-dependent monooxygenase activity of the recombinant yeast strains, respectively, as compared with that of the yeast cells expressing the corresponding P450 species. These results suggested that the overproduction of yeast P450 reductase with a simultaneous expression of the mammalian P450 species enhanced the P450c- and P450(17 alpha)-dependent monooxygenase activities in the recombinant yeast strains, probably due to the increased frequency of the interaction between yeast P450 reductase and P450c or P450(17 alpha) in the yeast microsomes.

Alcohol Dehydrogenase↗
PubMed1990

Alloimmunization with cultured human stomach cancer cell lines and the establishment of human-human hybridomas producing monoclonal antibodies.

Alloimmunization with the cultured human stomach cancer cell lines MKN-45 and MKN-28 was conducted and human-human hybridomas were established. Living MKN-45 cells (10(7) cells per injection) were injected monthly 34 times into one of the authors (K.K.) over 2 years and living MKN-28 cells (10(7) cells per injection) were co-injected 14 times after the 20th injection of MKN-45 alone. Cultured stomach cancer cells injected subcutaneously into K.K.'s forearm were rejected completely, although they grew transiently at the injection site. All the injections were made voluntarily at the direction of K.K. himself. Two human-human hybridomas producing monoclonal antibodies reactive with MKN-45 and MKN-28 cells, respectively, were separated from a hybridoma of human B-lymphoblastoid cell line named HO 323/WIL2-NS and lymphocytes in K.K.'s peripheral blood. One cell line of the hybridoma FMK-H3 produced IgM-type monoclonal antibody, and the other line, EMK-F7, produced IgG-type antibody. These two human-human monoclonal antibodies were highly reactive with MKN-45 and MKN-28 cells, weakly reactive with MKN-74 stomach cancer cell line, and not reactive with the other stomach cancer cell lines tested (MKN-1, MKN-7, TMK-1, NUGU-2, NUGC-3, NUGC-4 and KATO-III).

Adenocarcinoma↗
PubMed1990

Upshaw-Schulman syndrome in two siblings.

Upshaw-Schulman syndrome is a rare disease, and familial occurrence has not been reported. In this paper, two Japanese brothers, aged 2 and 6 years, with microangiopathic hemolytic anemia, thrombocytopenia and fragmented red cells from the newborn period are reported. Unusually large von Willebrand factor (vWF) multimers were found in the plasma samples from both cases during remission, while the quantities of the unusually large vWF multimers decreased greatly at a low platelet count. They were temporarily relieved from hemolytic anemia and thrombocytopenia by infusions of plasma from normal donors. It appears that our patients lack an unidentified plasma factor, which is genetically determined.

Anemia, Hemolytic, Congenital↗
PubMed1990

Adenosine exacerbates ischemic myocardial injury during regional coronary hypoxemia in the dog.

To investigate the myocardial protective effect of adenosine (ADO), the left anterior descending artery of 10 dogs was cannulated and perfused at a pressure of 100 mmHg. Hypoxic coronary perfusion was conducted for 60 min followed by 60 min of normoxic reperfusion (group 1, control, n = 5). In group 2 (n = 5), ADO was continuously infused at a rate of 40 micrograms/kg/min for 30 min before and during 60 min of hypoxic blood perfusion and for 60 min following normoxic reperfusion. In group 1, R wave amplitude and TQ segment of the epicardial surface electrocardiogram (EPIECG) were reduced, the ST segment was elevated, and a new Q wave developed during hypoxic blood perfusion. However, at 60 min of normoxic reperfusion, the R wave amplitude recovered to approximately 60% of its control value. Also, ST segment elevation was restored to normal and the new Q wave disappeared. The TQ segment returned to normal after approximately 20 min of hypoxic perfusion. Histological analysis showed myocardial infarction in the subendocardium, but not in the subepicardium. In group 2, EPIECG findings during hypoxic blood perfusion were similar to those observed in group 1. However, the recovery of ST segment elevation during normoxic reperfusion was slower than that observed in group 1. R wave restoration did not occur in group 2. Furthermore, the new Q wave remained present throughout the normoxic reperfusion period. Transmural infarction and severe congestion were observed histologically in this group. Obvious contraction bands were not demonstrated histologically in either group. These findings suggest that ADO did not protect myocardial viability during 60 min of hypoxic blood perfusion, but instead, ADO exacerbated ischemic injury during regional hypoxic perfusion.

Adenosine↗
PubMed1990

A novel human hepatoblastoma cell line (HuH-6KK) with rapid growth in serum-free medium without extracellular matrix.

A novel human hepatoblastoma cell line (HuH-6KK) with a high growth rate in a serum-free medium without extracellular matrix was developed from an original one, HuH-6 c15 (HuH). The original HuH cells (38 passages) did not proliferate well in RPMI 1640 medium containing 20% fetal calf serum (FCS). The HuH cells (HuH-6KK) with a high growth rate were selected by culturing them in an enriched RDF containing 20% FCS and 0.01% mucous polysaccharide (spirulinan) isolated from a blue-green alga, Spirulina subsalsa. The HuH-6KK cells showed a rapid growth in serum-free eRDF medium containing insulin, transferrin, ethanolamine, and selenite (eRDF-ITES medium) without fibronectin. The proliferation of the original HuH cells was also observed in the eRDF-ITES medium, but the growth was slow compared with the HuH-6KK cells. In the medium without ITES, the growth of the HuH-6KK and original HuH cells was slow. Among the ITES ingredients, insulin promoted the growth of HuH-6KK cells the most.

Blood↗
PubMed1990

Identification and characterization of receptors for protein import into chloroplasts and mitochondria.

An anti-idiotypic antibody approach was used to identify chloroplast and mitochondrial protein component(s) which interact with the corresponding signal sequence. The proteins thus identified can be operationally defined as receptor(s) for import of proteins into chloroplasts and mitochondria. The import receptor(s) was found in "contact sites" between the outer and inner membrane of chloroplast envelope or of mitochondria.

Antibodies, Anti-Idiotypic↗
PubMed1990

Pharmacological studies of 6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate. Effects on experimental pancreatitis.

The effects of FUT-187 (6-amidino-2-naphthyl 4-[(4,5-dihydro-1H-imidazol-2-yl)amino]benzoate dimethanesulfonate, CAS 103926-82-5), a novel synthetic protease inhibitor, were examined in experimental rat and canine models of pancreatitis. 1. FUT-187 significantly increased the survival of rats with trypsin- and phospholipase A2-induced pancreatitis in a dose-dependent manner (10-100 mg/kg, p.o.). 2. FUT-187 decreased plasma enzymatic activity reflecting the degree of pancreatitis in rats with ethionine-induced pancreatitis, and showed a tendency to ameliorate histopathological changes in the pancreas (10-100 mg/kg p.o.). 3. FUT-187 (10 mg/kg) produced an obvious improvement of various biochemical parameters of pancreatitis and also reduced histopathological changes in the pancreas in animals with experimental pancreatitis produced by the closed duodenal loop method. In addition, FUT-187 significantly increased the survival of dogs when given by direct administration into the lumen of the closed duodenal loop. The therapeutic effects of FUT-187 in experimental pancreatitis were nearly equal in most instances to those of camostat mesilate. Thus, FUT-187 would appear to be an effective new agent for the treatment of pancreatitis.

Acute Disease↗
PubMed1990

[A study on the outer shape of full cast crown. 1. Au-Pd-Ag alloy].

Recently, as the result of much research, cast crowns with a very accurate fit are being produced, and even on the clinical level satisfactory results have been achieved. Few reports, however, have been made on the outer shapes of full cast crowns and no clear results have been obtained in this field of research. In a previous report a newly developed apparatus and method were introduced by means of which the outer shapes of wax patterns and the casting made from them can be compared and evaluated, and the apparatus and method were shown to be very accurate. In the present study, the difference in the shapes of wax patterns and castings made from them was investigated using 12% Au-Pd-Ag alloy, the alloy used for restorations as stipulated by the National Health Insurance. Also, dry and wet asbestos was used to see if this affected the shape of the castings. The results are given below: 1. When day asbestos was used, the casting were the same size as the wax patterns at the marginal areas but became smaller towards the occlusal surface. The upper surface of the castings were lower than the wax patterns, being much closer to the occlusal surface itself. 2. When the asbestos was immersed in water before using it, the diameter of the casting above the marginal area was even smaller but at the occlusal surface the height of the casting was almost the same as the wax pattern. 3. It appears that better results may be obtained by using dry asbestos because of the possibility of reducing the space between the cast crown and occlusal surface of the tooth.

Asbestos↗
PubMed1990

[The physical properties of silicone impression materials with hydrophilicity and hydrophobicity. Wetting, water absorption, surface structure of dental stone and dimensional change on stone dies].

In order to compare the physical properties of the silicone impression materials with regard to their hydrophilicity and hydrophobicity, wetting and water absorption, the surface structure and dimensional changes of stone dies were investigated. The evaluation of wetting was performed on one kind of addition-type material with hydrophilicity, five kinds of addition-type materials with hydrophobicity and one kind of condensation-type silicone impression material. One kind of addition-type silicone impression material with hydrophilicity and hydrophobicity was used in other research. Wetting was assessed by measuring the contact angle between water and the impression materials. Water absorption was assessed by the change in weight of the impression materials after immersion in water. The surface structure of the dental stone was observed by SEM. The dimensional changes of stone dies were measured by means of an apparatus designed in this department. The results were as follows: 1. Wetting: The addition-type impression material with hydrophilicity had a 51.4 +/- 1.3 degree contact angle, and other impression materials varied from 84.6 +/- 6.1 degrees to 97.7 +/- 4.4 degrees. 2. Water absorption: The amount of water absorption of the hydrophilic type was greater than that of the hydrophobic type. 3. The surface structure of dental stone: In the case of Vermix stone, which was poured into water-immersed hydrophilic type material, the stone crystals became large, but Fujirock showed no change. 4. The dimensional change on stone dies: No difference was apparent between the hydrophilic type and the hydrophobicity type. 5. Hydrophilicity may affect the surface structure of the dental stone slightly but this is possible within the permissible clinical limits.

Absorption↗