Biomedical subjects

S Takao

Publications and source records attributed to S Takao.

At least 127 records · Page 7Linked to original sources

PubMed1993

Mouse tumor necrosis factor receptor type I: genomic structure, polymorphism, and identification of regulatory regions.

The mouse tumor necrosis factor receptor (TNFR)-I gene was cloned, sequenced, and characterized. The nucleotide sequence analysis shows that the TNFR-I is composed of 10 exons and nine introns. The first intron includes two simple dinucleotide repeat sequences, (GA)8 and (TC)9(TG)19. The (TC)9(TG)19 tandem repeat was found to be polymorphic in its length among various mouse strains. The nucleotide sequence of the 1076 bp 5' flanking region of the TNFR-I was also determined. Various possible regulatory sequences were identified in the 5' flanking region of the TNFR-I gene. For functional analysis, the 5' flanking region of the TNFR-I gene was isolated, ligated upstream of the luciferase reporter gene, and transiently transfected into L929, Hela, and a T cell hybridoma cell line. The results show that the isolated 5' flanking region has functional promoter activity and is responsible for constitutive expression of the TNFR-I gene. A series of truncated promoter constructs were generated and studied in a transient transfection system. Analysis of transient expression in L929 cells shows that the regions -1076/-939, -615/-425, and -425/-198 include positive regulatory elements, while the region -939/-615 may contain negative cis-acting elements for the constitutive expression of the TNFR-I. The shortest construct containing 198 bp of the 5' flanking region still has significant promoter activity, suggesting that the two GC-rich elements in this region may play an important role in the constitutive expression of the TNFR-I gene.

Animals↗

PubMed1993

Expression of the HN, F, NP and M proteins of Sendai virus by recombinant vaccinia viruses and their contribution to protective immunity against Sendai virus infections in mice.

Recombinant vaccinia viruses (RVVs) expressing each of the haemagglutinin-neuraminidase (HN), fusion (F), nucleocapsid (NP) and matrix (M) proteins of Sendai virus were constructed to investigate their capacities to induce protective immunity against Sendai virus infections. The proteins expressed in cultured cells appeared to be authentic with respect to their antigenicity, electrophoretic mobility, surface expression of the HN and F proteins and, in the case of the HN protein, biological activities. Mice inoculated intranasally with these RVVs developed serum antibodies to the respective Sendai virus proteins, suggesting their in vivo expression. In mice immunized with RVV carrying either the HN or the F gene, growth of the challenging Sendai virus was almost completely suppressed in the lung, indicating their capacities to induce effective protective immunity against Sendai virus infections. In contrast, in mice immunized with RVV carrying the NP or M gene, the challenging virus propagated as well as in the control mice, but the virus titres were significantly lower at the late stage of infection than those in the control mice, suggesting that they can also induce protective immunity especially at the late stage of the challenge infection.

Animals↗

PubMed1993

Cloning and characterization of a tryptophanase gene from Enterobacter aerogenes SM-18.

A tryptophanase gene from Enterobacter aerogenes SM-18 was cloned and sequenced. The structural gene for tryptophanase, tnaA, consisted of 1389 bp encoding 462 amino acid residues, and its nucleotide sequence and deduced amino acid sequence showed significant homology to those of tnaA from Escherichia coli K12. A short open reading frame consisting of 31 amino acid residues was found upstream of tnaA, and it showed some similarity to the E. coli tnaC gene known to be a cis-acting regulatory element for transcription. A partial open reading frame homologous to the 5' end of E. coli tnaB was observed at the 3'-flanking region of tnaA. These genes may thus constitute an operon as in E. coli.

Amino Acid Sequence↗

PubMed1992

Effect of a dihydropyridine analogue, 2-[benzyl(phenyl)amino]ethyl 1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo- 1,3,2-dioxaphosphorinan-2-yl)-1-(2-morpholinoethyl)-4-(3-nitrophenyl)-3 -pyridinecarboxylate on reversing in vivo resistance of tumor cells to adriamycin.

A newly synthesized dihydropyridine analogue, 2-[benzyl(phenyl)-amino]ethyl 1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorina n-2-yl)-1- (2-morpholinoethyl)-4-(3-nitrophenyl)-3-pyridinecarboxylate (PAK-200), at 5 microM inhibited the efflux of [3H]vincristine from KB-C2 cells and increased the accumulation of [3H]vincristine in KB-C2 cells to a level similar to that in KB-3-1 cells. PAK-200 inhibited the photoaffinity labeling of P-glycoprotein in KB-C2 membranes by [3H]azidopine. At 5 microM, PAK-200 enhanced the cytotoxic effect of Adriamycin on drug-sensitive KB-3-1 cells, multidrug-resistant KB-8-5 cells, and two human colorectal carcinoma tumor lines, COK-28LN and COK-36LN, by factors of 2, 5, 2, and 3 times, respectively. The calcium antagonistic activity of PAK-200 was about 1000 and 5 times lower than that of another dihydropyridine analogue, nicardipine, and of verapamil, respectively. PAK-200 in combination with Adriamycin completely suppressed the growth of KB-3-1 and COK-36LN and partially suppressed the growth of KB-8-5 but had no significant effect on COK-28LN cells xenografted in nude mice. The level of MDR1 expression of COK-36LN was about 3 times higher than that of COK-28LN, but lower than that of KB-8-5 cells. These results suggest that the interaction of PAK-200 with P-glycoprotein may be partly correlated with the enhancement of the antitumor effect of Adriamycin on xenografted KB-8-5 and COK-36LN cells in nude mice.

Animals↗

PubMed1992

Rapid and marked induction of hepatocyte growth factor during liver regeneration after ischemic or crush injury.

Liver injuries induced by ischemia or physical trauma are characterized by noninflammatory damage frequently observed in a clinical setting. When the liver of rats was injured by ischemic treatment or physical crushing, necrotic tissue degeneration occurred in several sites of lobulus within 24 hr. Hepatocyte growth factor, a potent mitogen for adult rat hepatocytes in primary culture, was markedly induced in the livers of rats injured by ischemia or physical trauma. In both cases, the hepatocyte growth factor messenger RNA level in the injured liver reached about 10 to 20 times that of the normal level during 12 to 24 hr after liver injury. The increase in hepatocyte growth factor messenger RNA correlated well with the degree of liver damage as evaluated by serum ALT activity in the sera of rats. In situ hybridization showed that hepatocyte growth factor messenger RNA expression occurs in nonparenchymal liver cells, primarily in Kupffer cells of the ischemic liver. After the increase of hepatocyte growth factor messenger RNA in the injured liver, a marked compensatory hepatocyte DNA synthesis occurred 48 to 72 hr after these treatments. These results suggest that hepatocyte growth factor acts as a hepatotropic factor for liver regeneration after noninflammatory liver damage caused by ischemia and physical crush, probably through a paracrine mechanism.

Animals↗

PubMed1992

A correlation between arterial ketone body ratio and concentration of beta-hydroxybutyrate as an indicator of hepatic functional reserve.

We have investigated the correlation between the arterial blood ketone body ratio (AKBR) and beta-hydroxybutyric acid (HBAC) in the course of a 75 g glucose tolerance test. The correlation was revealed to be represented by an equation of Y = A + BX [X = log(HBAC), Y = log(AKBR)] with high significance. This expression existed in both normal individuals and patients with liver, biliary tract or pancreas disease. The postoperative course was unsatisfactory because of liver dysfunction in cases whose value B was more than -0.6 in bisegmentectomy and more than -0.45 in uni- or subsegmentectomy. The coefficient B in the equation was suggested to contribute to the evaluation of hepatic functional reserve.

3-Hydroxybutyric Acid↗

PubMed1992

Monoclonal antibodies against a human gastric cancer cell line with lung metastatic potential in nude mice define antigens with different expression between the primary and metastatic liver lesions.

SCK-29 is a tumor cell line derived from human gastric adenocarcinoma with the feature of producing lung metastases when xenografted in nude mice. Monoclonal antibodies were produced against SCK-29 tumor cells or their glycoproteins prepared by affinity chromatography on a lectin-agarose column. Five antigens defined by the monoclonal antibodies MG-1 to MG-5 were expressed in a large number of gastric or colonic adenocarcinomas. Among the antigens, MG-1 and MG-3 proved to be tumor-associated, since they were detected only occasionally in normal tissues. MG-5 antigen was often detected in normal gastric mucosa but not in other tissues. The degree of expression of MG-1. MG-3 and MG-5 antigens differed considerably in metastatic lesions. In metastatic liver lesions of gastric adenocarcinoma, expression of these MG antigens was less marked than in primary tumors. MG-1 and MG-3 antigens were abolished by neuraminidase digestion and periodate oxidation. MG-5 antigen was likely to be a protein antigen, since it was resistant to neuraminidase digestion and to periodate oxidation but was sensitive to protease digestion.

Adenocarcinoma↗

PubMed1992

A novel core protein as well as polymorphic epithelial mucin carry peanut agglutinin binding sites in human gastric carcinoma cells: sequence analysis and examination of gene expression.

The peanut agglutinin (PNA)-binding site is protein-bound Gal beta 1-->3GalNAc, and is a tumor-associated carbohydrate marker expressed in many human carcinomas. PNA-binding glycoproteins isolated from KATO-III human gastric carcinoma cells were deglycosylated by trifluoromethanesulfonic acid, and rabbit antibodies against the core proteins were used to screen a lambda gt11 expression library constructed from these cells. Two different core proteins were identified by this approach. One was polymorphic epithelial mucin (PEM), initially found in breast carcinomas. PEM mRNA was expressed in normal tissues of the stomach, colon, and lung, but not in the small intestine, thyroid, and spleen. High levels of PEM mRNA were detected in some nude mouse-transplanted carcinomas, i.e. colorectal, pancreatic, stomach, and lung carcinomas. The other core protein was a novel one called MGC-24, which has a molecular mass of 24 kDa, is rich in hydroxyl amino acids and cysteine, and lacks repeating motifs. The mature MGC-24 glycoprotein behaved as a high-molecular-mass one upon SDS-polyacrylamide gel electrophoresis even after neuraminidase treatment. Treatment with endo-alpha-N-acetylgalactosaminidase in the absence of neuraminidase significantly changed the staining pattern by anti-MGC-24, confirming that MGC-24 carried PNA-binding sites. MGC-24 mRNA was intensely expressed in normal tissues of the colon, small intestine and thyroid, and in some nude mouse-transplanted colorectal and pancreatic adenocarcinomas.

Amino Acid Sequence↗

PubMed1992

Induction of Cellulase by Gentiobiose and Its Sulfur-Containing Analog in Penicillium purpurogenum.

Cellulase induction by beta-glucodisaccharides was investigated by using non-cellulase-induced mycelia of Penicillium purpurogenum P-26, a highly-cellulase-producing fungus. Gentiobiose induced significant amounts of cellulase compared with cellobiose when nojirimycin was added to the induction medium to inhibit extracellular beta-glucosidase activity. Thiogentiobiose (6-S-beta-d-glucopyranosyl-6-thio-d-glucose), a sulfur-containing analog of gentiobiose, was more effective for cellulase induction than gentiobiose even in the absence of nojirimycin. Thiogentiobiose appeared to be a gratuitous inducer since it was not metabolized during cellulase induction. Gentiobiose was formed from cellobiose by the intracellular beta-glucosidase of P. purpurogenum. These findings indicate that gentiobiose is an active inducer of cellulase for this fungus and may possibly be formed by intracellular beta-glucosidase from cellobiose.

Journal Article↗

PubMed1991

Tumorigenicity, invasion, and metastasis of human gastric cancer in nude mice.

Tumors derived from 105 patients with gastric cancer were subcutaneously heterotransplanted into nude mice in order to study their tumorigenicity and malignant behavior. Of the 105 gastric cancers, 45 were successfully transplanted (a 42.9% tumorigenesis rate). The tumorigenesis rate of Borrmann type 1 and 2 cancers (77.8%) was significantly higher than that of type 3 and 4 cancers (34.6%). Also, the tumorigenesis rate of differentiated carcinoma (57.1%) was significantly higher than that of undifferentiated carcinoma (30.9%). Spontaneous metastases from the subcutaneous tumors were observed in 5 of the 37 established tumor lines (13.5%), and macroscopic pulmonary metastases were common with one tumor line (SCK-29). Although most of the subcutaneous gastric cancers showed local expansion without distant metastasis, the same tumor cells implanted into the peritoneal cavity exhibited invasive growth and/or metastasis. Thus, the expression of a metastatic phenotype by human gastric cancer was influenced by the host microenvironment. The SCK-29 tumor line with its high metastatic potential may be useful for studies on the mechanism of blood-borne metastasis.

Animals↗

PubMed1991

Enhanced isolation of influenza virus in conventional plate cell cultures by using low-speed centrifugation from clinical specimens.

To determine whether low-speed centrifugation as a means of amplifying viral adsorption to target cells can enhance the sensitivity of conventional techniques for the isolation of influenza virus from clinical specimens, the authors conducted a simultaneous comparison between two conventional plate cell cultures--one with and one without centrifugation (700 X g, 60 minutes). Of 26 influenza virus isolates obtained from 528 clinical specimens, 17 were more efficiently isolated by the centrifugation assay compared with conventional culture methods. Centrifugation-assisted methods were found to be efficient in the recovery of 17 of 20 isolates (85%) not identified on first passage by conventional techniques. The number of isolates obtained with centrifugation was 1.5 times as high as that obtained with no centrifugation after three passages. The two assays were significantly different in the isolation of influenza virus (P less than 0.01). Since low-speed centrifugation may increase the infectivity of influenza virus in cell culture, this technique may prove useful in the efficient and rapid isolation of this virus from clinical specimens.

Animals↗

PubMed1991

IgG response is impaired in H2-c-fos transgenic mice.

Transgenic mice carrying the proto-oncogene c-fos under the control of H-2Kb promoter (c-fos mice) were generated from (C57BL/6 x SJL)F2 mice. One line was backcrossed with C57BL/6 mice for 10 generations. These semi-congenic c-fos mice express exogenous c-fos RNA in their hematopoietic tissues. The following immunological states are apparent. (i) Titers of serum IgM, IgG, and IgA of naive c-fos were within the control range. (ii) These mice could not produce primary IgG antibody specific for immunized antigen. (iii) Production of primary IgM and IgA antibody to the antigen was within the control range. (iv) There were no IgG memory B cells generated in the spleens of c-fos mice. (v) Activities of antigen-presenting cells and carrier-specific helper T cells from c-fos mice were normal. These findings strongly suggest that the immune abnormality of c-fos mice is in limiting B cell function to the production of IgG to immunized antigens.

Animals↗

PubMed1991

Possible collaboration between c-fos and c-myc proto-oncogene products in in vivo lymphomagenesis.

Transgenic mice carrying the exogenous c-myc gene under regulation of the Ig enhancer (Ig-c-myc) were mated with mice carrying exogenous c-fos gene under control of the H-2Kb promoter (H2-c-fos) to examine their functional collaboration in in vivo lymphomagenesis. Two of the 33 (c-fos x c-myc) mice developed pre-B cell lymphomas within 22 weeks of age. None of the other F1 progeny expressing c-fos or c-myc alone showed malignant change within 14 months of age, suggesting that the exogenous c-fos and c-myc collaborate in in vivo lymphomagenesis. The exogenous c-myc RNA was overexpressed in the lymphomas, but the amount of exogenous c-fos RNA was not affected, suggesting that the large abundance of c-myc protein is a prerequisite for lymphoma onset or progression and c-fos protein plays a complementary role. C-fos protein induced immunodeficiency in the (c-fos x c-myc) mice like H2-c-fos mice. Natural killer cell activity of (c-fos x c-myc) mice was partially impaired. Therefore, these lymphomas may be a consequence of the synergism of two independent actions caused by the exogenous c-myc (lymphomagenesis) and the exogenous c-fos (low NK activity) in (c-fos x c-myc) mice.

Animals↗

PubMed1991

[A case of local recurrence of rectal cancer successfully treated by UFT combined with two-route CDDP chemotherapy under the AT-II induced hypertension].

A case of local recurrence of rectal cancer was successfully treated by UFT combined with two-route CDDP chemotherapy under the AT-II induced hypertension. UFT (600 mg/day) was orally administered every day. CDDP (75 mg/m2) was infused into the right internal iliac artery via subcutaneously grafted Infuse-a-port under hypertensive state induced by the AT-II (3 micrograms/min). Sodium thiosulfate was intravenously given to protect the CDDP induced nephrotoxicity. The recurrence tumor palpated by digital examination and revealed by MRI disappeared after the fourth two-route CDDP chemotherapy. The serum CEA level elevated before the treatment also normalized. This combined chemotherapy was considered to be an effective measure to cure the local recurrence of rectal cancer.

Adenocarcinoma↗

PubMed1990

Immediate protection of mice from lethal wild-type Sendai virus (HVJ) infections by a temperature-sensitive mutant, HVJpi, possessing homologous interfering capacity.

Protection of mice from lethal Sendai virus (HVJ) infections by a temperature-sensitive mutant, HVJpi, which was isolated from a carrier culture, was studied. HVJpi had a strong interfering capacity with the replication of virulent wild-type virus in LLCMK2 cells. When a high dose of HVJpi (3.0 x 10(7) CIU) was inoculated intranasally into mice, the mice showed neither illness nor lung lesions but gained significant resistance against the challenge of virulent wild-type virus (18 LD50) immediately after inoculation. In contrast, the mice inoculated with a lower dose of HVJpi (8.2 x 10(5) CIU) did not show the immediate resistance but became immune several days after inoculation. Time courses of the virus replication in the lung revealed that the replication of wild-type virus was strongly suppressed to about 1/1000 by the simultaneous infection with a high dose of HVJpi, thus resulting in minimizing the lung lesions and survival of all the mice infected. Neither interferon nor natural killer cells appeared to play a major role in the immediate immune status by HVJpi, since no difference was observed in protection of mice simultaneously infected with wild-type virus and HVJpi in spite of pretreatment of the mice with anti-interferon and anti-asialo GM1 antibodies as compared with that of the untreated doubly infected mice. On the other hand, it was suggested by analysis of viral polypeptides synthesized in the lung of infected mice by Western blotting that the early stage of replication of wild-type virus in the lung was inhibited mainly by the interfering capacity of HVJpi. These results indicate that HVJpi is an unique virus mutant which is capable of protecting mice from lethal Sendai virus infections by its interfering capacity immediately after inoculation and then by the induction of virus-specific immune responses.

Animals↗

PubMed1990

Enhancing effect of centrifugation on isolation of influenza virus from clinical specimens.

The use of centrifugation (700 x g, 60 min) in a plaque assay markedly increased (mean, 2.9-fold) the infectivity of all 42 influenza virus strains tested, compared with no centrifugation. Of 13 influenza virus strains isolated from 390 clinical specimens, 9 (69%) were efficiently isolated by the centrifugation assay compared with conventional culture methods. The centrifugation assay may be useful for isolating the influenza virus from clinical specimens.

Centrifugation↗

PubMed1989

Endoproteolytic activation of Newcastle disease virus fusion proteins requires an intracellular acidic environment.

Effects of weak bases, chloroquine and ammonium chloride, on the intracellular cleavage of the fusion protein precursor (F0) were examined in BHK cells infected with a virulent strain of Newcastle disease virus (NDV). Most of F0 molecules synthesized during a 15-min pulse period were chased out because of cleavage into F1 and F2 within a 60-min chase period in the absence of the weak bases. In contrast, significant amounts of the precursor were found to remain uncleaved when chloroquine or ammonium chloride was present. The uncleaved fusion proteins were incorporated into progeny virions as efficiently as cleaved ones, and about the half of fusion proteins were present as F0 in the virion released by the cells treated with 0.3 mM chloroquine. Taken together with the finding that the trans cisternae of Golgi apparatus and forming secretory vesicles have an acidic pH (K. G. W. Anderson and R. K. Pathak, Cell, 40, 685-643, 1985), the present results suggest that an acidic environment in these compartments is required for intracellular proteolytic activation of NDV fusion proteins.

Ammonium Chloride↗

PubMed1989

Human endothelial cell growth factors derived from thyroid anaplastic cell carcinoma.

Human endothelial cell growth factors were partially isolated from transplanted thyroid anaplastic cell carcinoma propagated in nude mice. Purification was monitored in human umbilical cord vein endothelial cell cultures by (3H)-thymidine incorporation into DNA. Crude tumor extracts with 0.1 M Tris-HCl, pH 7.2 were fractionated by ammonium sulfate precipitation. The active materials precipitated by 35% to 50% ammonium sulfate were further purified by Bio-Rex 70 (Bio-Rad, Richmond, Calif.) cation exchange chromatography. Active fractions eluted by 0.5 M to 0.7 M NaCl were further analyzed via heparin-sepharose affinity chromatography. This resulted in separation of one major peak eluted by 0.9 M to 1.2 M NaCl and confirmed to promote human umbilical cord vein endothelial cell proliferations, and three other peaks. The molecular weight determination of the most active fraction performed by high-pressure liquid chromatography utilizing TSK 2000 gel column indicates 41,000 and 19,000 daltons for the active materials, respectively. Our results demonstrate that the angiogenesis properties of a solid tumor (thyroid anaplastic cell carcinoma), are not composed of a simple mechanism in vivo.

Angiogenesis Inducing Agents↗