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Biomedical subjects

M Numata

Publications and source records attributed to M Numata.

At least 73 records · Page 4Linked to original sources
PubMed1994

Protein ubiquitination in the posterior silk glands of Bombyx mori.

Ubiquitin gene expression and the ubiquitination of proteins in the posterior silk glands (PSG) of B. mori were analyzed developmentally with respect to fibroin synthesis and degeneration. Two ubiquitin transcripts are expressed throughout larval stages, and the level of each transcript is regulated differently. The larger transcript, a polyubiquitin mRNA, was abundant during the molt stage, while levels of the smaller ubiquitin transcript increased immediately after molting. Only a single 65 kDa ubiquitinated protein was detected late in the 5th instar, and the amount increased up to spinning stage. This ubiquitinated protein may participate in the PSG degeneration.

Animals↗
PubMed1994

Expression of DNA methyltransferase gene in mature and immature neurons as well as proliferating cells in mice.

A major role of DNA-methyltransferase (MTase) is thought to be maintaining the DNA methylation profile through DNA replication. However, previous surveys of mRNA distribution in different tissues by Northern-blot analysis have shown unexpectedly high levels of expression of DNA-MTase mRNA in adult mouse brain, which consists mostly of slowly proliferating glial and nonproliferating neuronal cells. In order to identify cells expressing the gene in the brain, we performed an in situ hybridization analysis of mature brain as well as whole embryos of different ages. In addition to various embryonic tissues with active cell proliferation such as the ventricular neurogenic layer, hair follicle epithelia, thymus and epithelia of the base of intestinal villi, almost all mature neurons in brain of adult and even aged mice expressed DNA-MTase mRNA at substantial levels. No significant expression of the gene was detected in the white matter. These findings suggest some neuron-specific biological function of DNA methylation, unrelated to DNA replication.

Animals↗
PubMed1994

Antitumor components isolated from the Chinese herbal medicine Coix lachryma-jobi.

The seeds of the gramineous plant Coix lachryma-jobi L. var. ma-yuen Stapf are a traditional Chinese medicine possessing antitumor activity. An acetone extract of the seeds was fractionated by the aqueous alkali method and by silica gel column chromatography in order to identify the antitumor components. Antitumor activity, as assayed by an in vivo growth inhibition test on a transplantable mouse tumor, was attributed to an acidic fraction. Infrared spectroscopy and gas-liquid chromatography showed that this acidic fraction was composed of four free fatty acids: palmitic, stearic, oleic, and linoleic acids.

Animals↗
PubMed1994

Expression and localization of the mRNA for DNA (cytosine-5)- methyltransferase in mouse seminiferous tubules.

DNA (cytosine-5)-methyltransferase (DNA MTase) is the only enzyme known to be involved in the methylation of mammalian DNA. Although the expression of DNA MTase gene is abundant in the testis, little is known about the role of this enzyme during spermatogenesis. We examined the distribution of DNA MTase mRNA in mouse testis by in situ hybridization histochemistry with an oligonucleotide probe. The mRNA signal was observed in the seminiferous tubules and was localized predominantly in spermatogonia and spermatocytes, particularly during the earlier steps of meiotic prophase I, with maximal intensity in the early pachytene cells. These results suggest some significant role for DNA MTase in spermatogenesis.

Animals↗
PubMed1993

Identification of cellular defect in UVS1, a UV-sensitive Chinese hamster ovary mutant cell line.

UVS1 is an intermediately UV-sensitive Chinese hamster ovary mutant originally isolated by its hypersensitivity to an anticancer drug, 1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3-(2-chloroethyl)-3-nitrosour ea hydrochloride. By cell fusion analysis, UVS1 complemented the UV sensitivity of the mouse lymphoma cell line US31 from the eighth complementation group of UV-sensitive rodent cell lines. By enzyme-linked immunosorbent assay we found that within 3 h after UV irradiation both pyrimidine dimers and (6-4)photoproducts in UVS1 were not removed from chromosomal DNA in UVS1 at all. Twenty-four h after UV irradiation the removal rate of (6-4)photoproducts was intermediate between CHO9, the parental cell line, and 43-3B, a UV-hypersensitive Chinese hamster ovary mutant of the complementation group 1, whereas the pyrimidine dimers in UVS1 were removed less efficiently as 43-3B. Alkaline elution assay showed that the incising activity to damaged DNA after UV irradiation of UVS1 was as low as that of 43-3B. The number of 1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3-(2-chloroethyl)-3-nitrosour ea hydrochloride-induced DNA interstrand cross-links of UVS1 was almost equal to that of 43-3B and about 1.5 times more than that of CHO9, suggesting that the gene products defective in UVS1 and 43-3B are essential for the excision repair of DNA damages produced by 1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3-(2-chloroethyl)-3-nitrosour ea hydrochloride.

Animals↗
PubMed1993

Changes in the cardiovascular and respiratory systems during laparoscopic cholecystectomy.

The effects of peritoneal insufflation on the cardiovascular and respiratory systems were investigated in eight patients who underwent laparoscopic cholecystectomy. During the operation, intraabdominal pressure was maintained at a constant 12 mm Hg with carbon dioxide. The cardiac index had increased significantly at 20 and 40 min after the start of insufflation (3.6 +/- 0.6, 3.9 +/- 0.8 mL/min, respectively) and after evacuation (4.2 +/- 0.6 mL/min) compared with the control value (3.2 +/- 0.6 mL/min). Mean arterial pressure was significantly increased at 20 min after the start of insufflation (94.6 +/- 11.2 mm Hg) relative to the control value (79.9 +/- 11.1 mm Hg) and remained high after evacuation (101.5 +/- 11.9 mm Hg). Central and femoral venous pressure rose significantly during the operation from baseline values (12 +/- 6 and 4 +/- 4 mm Hg, respectively) to 18 +/- 10 and 11 +/- 6 mm Hg, respectively, at 20 min, and to 18 +/- 10 and 19 +/- 8 mm Hg, respectively, at 40 min after the start of insufflation. These parameters returned to control levels immediately after evacuation. Dynamic lung compliance decreased by 25% as a result of the elevated intraabdominal pressure. These findings demonstrate that some cardiopulmonary changes occur even at an intraabdominal pressure of 12 mm Hg, which up to now has been considered a safe level.

Carbon Dioxide↗
PubMed1993

Generation of a monoclonal antibody specific for ganglioside GM4: evidence for GM4 expression on astrocytes in chicken cerebellum.

We established a murine monoclonal antibody (MAb) specific for ganglioside GM4 by immunizing C3H/HeN mice with chemically synthesized GM4 adsorbed to Salmonella minnesota, followed by fusion with mouse myeloma cells. The MAb, designated as AMR10, was shown to exhibit high binding specificity, reacting only with the ganglioside GM4 used for immunization and native GM4 from human brain. We determined the distribution of GM4 in adult chicken cerebellum by means of the immunofluorescence technique with the MAb. Our study revealed that GM4 expression was associated with astrocytes in the granular layer and the white matter, but not with myelin in any layers of the chicken cerebellar cortex.

Animals↗
PubMed1993

[DNA fingerprint method of the cultured cells].

DNA fingerprint method is very available not only to examine the cross-contamination of cultured cell lines and their origins and but to know the somatic mutation frequency in the cultured cells by exposure of radiation and chemicals. The method for DNA fingerprint was grouped in the following four types in term of probe; multilocus minisatellite probe, simple sequence repeat probe, locus specific minisatellite probe and repeat unit sequence variation in minisatellites.

Cell Line↗
PubMed1992

Identification of the eleventh complementation group of UV-sensitive excision repair-defective rodent mutants.

The drug-sensitive mutant UVS1, isolated from the Chinese hamster cell line CHO9, was previously found to complement the UV sensitivity of the excision repair-defective rodent mutants representative of groups 1 to 8 (Hata et al., Cancer Res., 51: 195-198, 1991; M. Numata et al., personal communication). Recently two new complementation groups of UV-sensitive CHO mutants, e.g., groups 9 and 10, have been identified (Stefanini et al., Cancer Res., 51: 3965-3971, 1991). In this paper we demonstrate that the repair defect in UVS1 cells is genetically different from those present in the mutants CHO7PV and CHO4PV, representing groups 9 and 10, respectively. Therefore, UVS1 represents a new complementation group of UV-sensitive rodent cell lines, the eleventh group.

Animals↗
PubMed1992

Total synthesis of the modified ganglioside de-N-acetyl-GM3 and some analogs.

Methyl[methyl 4,7,8,9-tetra-O-acetyl-5-(tert-butoxycarbonylamino)-3,5- dideoxy-2-thio-D-glycero-alpha-D-galacto-2-nonulopyranosid]onat e was used for the glycosylation of benzyl O-(2,6-di-O-benzyl-beta-D-galactopyranosyl)- and benzyl O-(2,3-di-O-benzyl-beta-D-galactopyranosyl)-(1----4)-3,6-di-O-benzyl- 2-O-pivaloyl-beta-D-glucopyranoside to give benzyl O-[methyl 4,7,8,9-tetra-O-acetyl-5-(tert-butoxycarbonylamino)- 3,5-dideoxy-D-glycero-alpha-D-galacto-2-nonulopyranosylonate]-(2-- --3)-O-(2,6-di-O-benzyl-beta-D-galactopyranosyl)-(21) and benzyl O-[methyl 4,7,8,9-tetra-O-acetyl-5-(tert-butoxycarbonylamino)-3,5- dideoxy-D-glycero-alpha-D-galacto-2-nonulopyranosylonate]-(2----6) -O-(2,3-di- O-benzyl-beta-D-galactopyranosyl)-(1----4)-3,6-di-O-benzyl-2-O-pivaloyl- beta-D-glucopyranoside (18), respectively, accompanied by the beta-linked isomers 22 and 19, respectively. Compounds 18, 21, and 22 were converted into the corresponding glycotriosyl donors which, upon coupling with (2S,3R,4E)-3-O-benzoyl-2-N-tetracosanoylsphingenine, afforded completely protected ganglioside analogs 39, 40, and 41, respectively. Deprotection of 40, 41, and 39 completed the synthesis of the modified ganglioside de-N-acetyl-GM3, a stereoisomer, and a regioisomer. The N-deprotected forms of 40 and 39, on successive treatment with methyl isocyanate and O-deprotection, gave the N-(N-methylcarbamoyl) analogs of GM3 and its regioisomer.

Carbohydrate Sequence↗
PubMed1992

Anticancer effects of free polyunsaturated fatty acids in an oily lymphographic agent following intrahepatic arterial administration to a rabbit bearing VX-2 tumor.

The anti-hepatic cancer effects of three free polyunsaturated fatty acids (linoleic, alpha-linolenic, and gamma-linolenic acids) dissolved in an oily lymphographic agent, Lipiodol Ultra-Fluid (Lipiodol), following intrahepatic arterial administration were examined using a rabbit liver cancer model, VX-2. The tumor was inoculated into the subcapsular parenchyma of the liver of rabbits, and Lipiodol alone or Lipiodol containing each one of the free fatty acids was administered into the hepatic artery 14 days after inoculation. The rabbits were sacrificed 7 days after administration. Lipiodol containing one of the fatty acids selectively remained in the tumor area. Although VX-2 tumor grew extensively in both the untreated group and the group that received Lipiodol alone, growth of VX-2 tumor was greatly suppressed in the group that received Lipiodol containing the free fatty acid. Pathological observation also showed that Lipiodol containing the free fatty acid had an anticancer effect on VX-2 tumor growing in the liver of rabbits. Average survival days in the group treated with Lipiodol containing gamma-linolenic acid were significantly prolonged compared with those in the control groups. Although growth rates of the tumor at the death of rabbits were large in the control groups, VX-2 tumor shrank at death of five rabbits of six in the group treated with Lipiodol containing gamma-linolenic acid. These results suggest that the intrahepatic arterial administration of Lipiodol containing the free fatty acids is an effective method of delivery of these fatty acids as anticancer agents.

Animals↗
PubMed1992

Electrotransformation of Thiobacillus ferrooxidans with plasmids containing a mer determinant.

The mer operon from a strain of Thiobacillus ferrooxidans (C. Inoue, K. Sugawara, and T. Kusano, Mol. Microbiol. 5:2707-2718, 1991) consists of the regulatory gene merR and an operator-promoter region followed by merC and merA structural genes and differs from other known gram-negative mer operons. We have constructed four potential shuttle plasmids composed of a T. ferrooxidans-borne cryptic plasmid, a pUC18 plasmid, and the above-mentioned mer determinant as a selectable marker. Mercury ion-sensitive T. ferrooxidans strains were electroporated with constructed plasmids, and one strain, Y4-3 (of 30 independent strains tested), was found to have a transformation efficiency of 120 to 200 mercury-resistant colonies per microgram of plasmid DNA. This recipient strain was confirmed to be T. ferrooxidans by physiological, morphological, and chemotaxonomical data. The transformants carried a plasmid with no physical rearrangements through 25 passages under no selective pressure. Cell extracts showed mercury ion-dependent NADPH oxidation activity.

Blotting, Southern↗
PubMed1992

DNA repair pathways in mammalian cells analyzed by isolation of ACNU-sensitive Chinese hamster ovary cells.

1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3-(2-chloroethyl)-3- nitrosourea hydrochloride (ACNU) causes chloroethylation of DNA strand followed by cross linking through an ethylene bridge. We recently isolated two ACNU sensitive mutants from mutagenized Chinese hamster ovary cells, and found them to be new drug sensitive recessive mutants (Hata et al. 1991). The O6-methyl guanine DNA methyl transferase (MT) activities of these cells were undetectable as the parental cell line, indicating that the sensitivity of the mutant cell lines to ACNU was not due to the decreased cellular level of this enzyme. By complementation analysis with the 7 established UV-sensitive CHO cell lines, one of the mutants, UVS1, turned out to complement their UV-sensitivity and, therefore, build a new complementation group among all the CHO cell lines ever reported. The other mutant, CNU1 showed hypersensitivity only to chlorethylating agents (ACNU, CCNU) and exhibited a slightly reduced unscheduled DNA synthesis (UDS) induced by UV. It is, therefore, suggestive that this mutant is defective in a specific step of DNA repair systems, which is important for the processing of DNA damages produced by ACNU. Only cell lines from the complementation group 1 and 4 out of 7 established complementation groups of UV-sensitive CHO mutants were more sensitive to ACNU than UVS1 and CNU1, indicating some steps of excision repair pathways as well as specific repair system play important roles in repairing ACNU-induced DNA damages.

Animals↗
PubMed1991

Isolation of two chloroethylnitrosourea-sensitive Chinese hamster cell lines.

1-[(4-Amino-2-methylpyrimidin-5-yl)methyl]-3-(2-chloroethyl)-3- nitrosourea hydrochloride (ACNU), a cancer chemotherapeutic bifunctional alkylating agent, causes chloroethylation of DNA and subsequent DNA strand cross-linking through an ethylene bridge. We isolated and characterized two ACNU-sensitive mutants from mutagenized Chinese hamster ovary cells and found them to be new drug-sensitive recessive Chinese hamster mutants. Both mutants were sensitive to various monofunctional alkylating agents in a way similar to that of the parental cell lines CHO9. One mutant (UVS1) was cross-sensitive to UV and complemented the UV sensitivity of all Chinese hamster cell lines of 7 established complementation groups. Since UV-induced unscheduled DNA synthesis was very low, a new locus related to excision repair is thought to be defective in this cell line. Another ACNU-sensitive mutant, CNU1, was slightly more sensitive to UV than the parent cell line. CNU1 was cross-sensitive to 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea and slightly more sensitive to mitomycin C. No increased accumulation of ACNU and a low level of UV-induced unscheduled DNA synthesis in this cell as compared with the parental cell line suggest that there is abnormality in a repair response of this mutant cell to some types of DNA cross-links.

Animals↗
PubMed1991

[Effects of various forms of gastric surgery on gut hormones and pancreatic secretions].

Effects of various forms of gastric surgery on gut hormones and pancreatic secretions were examined using canine models. These operative procedures included simple laparotomy (group A; n = 13), truncal vagotomy with pyloroplasty (B; n = 17), selective proximal vagotomy (C; n = 17), proximal gastrectomy with pyloroplasty (D; n = 6), proximal gastrectomy with truncal vagotomy and pyloroplasty (E; n = 7), and distal gastrectomy (F; n = 19). The mean fasting serum gastrin and secretin levels (pg/ml) were 71.0, 82.5 in A, 94.0, 97.7 in B, 62.1, 108.1 in C, 58.2, 123.0 in D, 91.2, 138.6 in E, and 50.9, 74.5 in F, respectively. The mean value of plasma pancreatic glucagon (pg/ml) showed 73.6, 109.9, 106.8, 47.2, 37.8, and 74.5 in each of the six groups. Significant correlations were observed between values of serum lipase and those of serum gastrin as well as between the amount of pancreatic secretions and serum secretin levels. Pancreatic secretions were decreased markedly in group F and moderately in B. Basal tissue blood flow measured by hydrogen clearance method was low in D, E, and F when compared with that in A.

Animals↗
PubMed1990

An efficient synthesis of ganglioside GM3: highly stereocontrolled glycosylations by use of auxiliaries.

An efficiently stereocontrolled total synthesis of GM3 alpha-D-Neup5Ac-(2----3)-beta-D-Galp-(1----4)-beta-D-Glcp-(1----1) -Cer was achieved by employing both methyl 5-acetamido-4,7,8,9-tetra-O-benzyl-2-bromo-2,3,5-trideoxy-3- phenylthio-D-erythro-beta-L-gluco-2-nonulopyranosonate for the key sialylation step, and O-[methyl(5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha -D-galacto-2-nonulopyranosyl)onate]-(2----3)-O-(2,4,6-tri-O- acetyl-beta-D-galactopyranosyl-(1----4)-3,6-di-O-acetyl-2-O-pivaloyl- alpha-D-glucopyranosyl trichloroacetimidate and fluoride for the key coupling step with a ceramide derivative. These two steps were significantly altered and improved in comparison with our previous synthesis that had been executed without use of stereocontrolling auxiliaries. GM3 was obtained in 4.5% overall yield in 19 steps starting from allyl O-(2,6-di-O-acetyl-3,4-O-isopropylidene-beta-D-galactopyranosyl)-(1----4 )-2,3,6-tri-O-acetyl-beta-D-glucopyranoside.

Carbohydrate Conformation↗