Biomedical subjects

K Yoshimatsu

Publications and source records attributed to K Yoshimatsu.

At least 37 records · Page 2Linked to original sources

PubMed2001

Inducible prostaglandin E synthase is overexpressed in non-small cell lung cancer.

An inducible microsomal form of human prostaglandin E synthase (mPGES) was recently identified. This enzyme converts the cyclooxygenase (COX) product, prostaglandin (PG) H2, to PGE2, a prostanoid that has been implicated in carcinogenesis. Increased amounts of PGE2 are detected in many types of cancer, but the underlying mechanism is not fully understood. Hence, we compared amounts of mPGES in 19 paired samples (tumor and adjacent normal tissue) of non-small cell lung cancer (NSCLC). By immunoblot analysis, mPGES was overexpressed in about 80% of NSCLCs. Immunohistochemistry localized the expression of mPGES to neoplastic epithelial cells. COX-2 was also commonly up-regulated in these tumors; marked differences in the extent of up-regulation of mPGES and COX-2 were observed in individual tumors. Cell culture was used to define the underlying mechanism(s) that accounts for up-regulation of mPGES in NSCLC. As reported previously for COX-2, levels of mPGES mRNA and protein were increased in NSCLC cell lines containing mutant Ras as compared with a nontumorigenic bronchial epithelial cell line. Nuclear run-offs revealed increased rates of mPGES transcription in the transformed cell lines. Overexpression of Ras caused a severalfold increase in mPGES promoter activity in nontransformed cells. Tumor necrosis factor-alpha induced mPGES and COX-2 in NSCLC cell lines but had no effect on the expression of either enzyme in a nontumorigenic bronchial epithelial cell line. Consistent with prior observations for COX-2, these data suggest that both cellular transformation and cytokines contribute to the up-regulation of mPGES in NSCLC.

Carcinoma, Non-Small-Cell Lung↗

PubMed2001

Epizootiological survey of hantavirus among rodent species in Ningxia Hui Autonomous Province, China.

Hantaviral antibodies were detected in the sera from Apodemus (A.) agrarius and A. peninsulae captured in Ningxia province, China by several different serological diagnostic methods. A total of 409 sera from rodent and insectivore species were collected in 1999 and examined by indirect immunofluorescent antibody assay (IFA). Among them, 19 of 191 (9.9%) sera of A. agrarius and 1 of 13 (7.7%) sera of A. peninsulae were positive for hantaviral antibodies. The other species (Rattus norvegicus, Mus musculus, Cricetulus triton, and Sorex cylindricauda) were negative. The reaction pattern of positive serum was characterized as scattered and granular virus antigens in the cytoplasm of hantavirus infected Vero E6 cells. Some of the A. agrarius sera positive for hantavirus were further examined by Western blotting (WB), enzyme-linked immunosorbent assay (ELISA), and the focus reduction neutralization test (FRNT). By WB, positive sera showed the same specific reaction pattern of baculovirus-expressed recombinant hantaviral nucleocapsid protein, as shown in hantavirus-immune serum. By ELISA, IFA-positive sera showed significantly higher optical densities (around 1.0) than the negative A. agrarius sera. Hantaan type hantavirus was neutralized with the positive sera. These results suggest that A. agrarius have hantavirus infection and may play a role as a reservoir animal for hantavirus in Ningxia Hui Autonomous Province, China.

Animals↗

PubMed2001

Inducible microsomal prostaglandin E synthase is overexpressed in colorectal adenomas and cancer.

Recently, an inducible microsomal human prostaglandin E synthase (mPGES) was identified. This enzyme converts the cyclooxygenase (COX) product prostaglandin (PG) H(2) to PGE(2), an eicosanoid that has been linked to carcinogenesis. Increased amounts of PGE(2) have been observed in many tumor types including colorectal adenomas and cancers. To further elucidate the mechanism responsible for increased levels of PGE(2) in colorectal tumors, we determined the amounts of mPGES and COX-2 in 18 paired samples (tumor and adjacent normal) of colorectal cancer. With immunoblot analysis, mPGES was overexpressed in 83% of colorectal cancers. COX-2 was also commonly up-regulated in these tumors; marked differences in the extent of up-regulation of mPGES and COX-2 were observed in individual tumors. Immunohistochemistry revealed increased mPGES immunoreactivity in neoplastic cells in both colorectal adenomas and cancers compared with adjacent normal colonic epithelium. Cell culture was used to investigate the regulation of mPGES and COX-2. Chenodeoxycholate markedly induced COX-2 but not mPGES in colorectal cancer cells. Tumor necrosis factor-alpha induced both mPGES and COX-2, but the time course and magnitude of induction differed. As reported previously for COX-2, overexpressing Ras caused a several-fold increase in mPGES promoter activity. Taken together, our results suggest that overexpression of mPGES in addition to COX-2 contributes to increased amounts of PGE(2) in colorectal adenomas and cancer. The mechanisms controlling the expression of these two enzymes are not identical.

Adenocarcinoma↗

PubMed2001

Isoquinoline alkaloid production by transformed cultures of Papaver somniferum.

Three clones of transformed cultures of opium poppy (Papaver somniferum L.) were established by infection with Agrobacterium rhizogenes MAFF 03-01724. MAFF clone 1 being capable of forming somatic embryos was selected and its growth and isoquinoline alkaloid production was investigated. The illumination, temperature and nutrient medium composition greatly affected growth, cell morphology and alkaloid accumulation. The MAFF clone 1 cultured in Root Culture medium in the dark at 22 degrees C accumulated a high quantity of sanguinarine (652 micrograms/g dry weight) though the growth was poor (4.4 fold as fresh weight basis after 2 months of culture). The MAFF clone 1 cultured in a quarter macro salt strength Woody Plant medium under 14 h/day light at 22 degrees C developed into plantlets and accumulated significant quantity of codeine (648 micrograms/g dry wt) together with papaverine, noscapine, and sanguinarine. This clone was applied to a rotating drum fermenter (2 L working volume), and ca. 0.3 mg codeine and 0.06 mg sanguinarine were obtained after 4 weeks of culture. One quarter of the codeine produced was found in the culture medium.

Alkaloids↗

PubMed2000

Genetic diversity of hantaviruses isolated in china and characterization of novel hantaviruses isolated from Niviventer confucianus and Rattus rattus.

The antigenic and genetic properties of 46 hantaviruses from China, 13 from patients, 23 from rodents, and 10 from unknown hosts, were compared with those of other hantaviruses. The viruses were classified as either Hantaan (HTN) or Seoul (SEO) viruses. A phylogenetic analysis of the partial M (300 bp) and S (around 485 bp) genomes of HTN viruses identified nine distinct genetic subtypes, one consisting of isolates from Korea. The SEO viruses were divided into five genetic subtypes, although they had less variability than the HTN subtypes. There was a correlation between the subtype and province of origin for four subtypes of HTN viruses, confirming geographical clustering. Hantaan virus NC167 isolated from Niviventer confucianus and SEO virus Gou3 isolated from Rattus rattus were the basal clades in each virus. The phylogenetic trees constructed from the entire S and M segments suggested that NC167 was introduced to N. confucianus in a host-switching event. The reactivity of a panel of 35 monoclonal antibodies was almost exactly the same in NC167 and a representative HTN virus and in Gou3 and a representative SEO virus. However, there was a one-way cross-neutralization between them. These results confirm the varied nature of Murinae-associated hantaviruses in China.

Animals↗

PubMed2000

Endogenous AP-1 levels necessary for oncogenic activity are higher than those sufficient to support normal growth.

We investigated the role of endogenous AP-1 in human tumor cell lines by introducing SupJunD-1, a dominant-negative mutant of AP-1, using vesicular stomatitis virus G protein (VSV-G)-pseudotyped retrovirus vectors. Single inoculation of six human tumor cell lines, originating from osteosarcomas, non-small cell lung carcinomas or cervical carcinomas, with recombinant SupJunD-1 virus at a high multiplicity of infection readily inhibited colony formation in soft agar. We detected no significant changes in expression levels of AP-1 components c-Jun or Fra-1, adhesion molecules CD44 or E-cadherin, or cell cycle regulator p53, which are encoded by genes previously reported to be under the control of AP-1 in some mouse or human cell lines. By varying the dosage of VSV-G-pseudotyped retrovirus, we were able to change the proviral copy number of supjunD-1 from 1 to approximately 10 and monitor suppression of endogenous AP-1 function as assessed by growth characteristics of the tumor cell lines, we found a SupJunD-1 dosage which significantly suppressed anchorage-independent growth without affecting the cellular growth in monolayer cultures at all. We conclude that endogenous AP-1 levels necessary for oncogenic activity are much higher than those sufficient to support normal growth.

3T3 Cells↗

PubMed2000

A focused compound library of novel N-(7-indolyl)benzenesulfonamides for the discovery of potent cell cycle inhibitors.

A series of compounds containing an N-(7-indolyl)benzenesulfonamide pharmacophore was synthesized and evaluated as a potential antitumor agent. Cell cycle analysis with P388 murine leukemia cells revealed that there were two different classes of potent cell cycle inhibitors; one disrupted mitosis and the other caused G1 accumulation. Herein described is the SAR summary of the substituent patterns on this pharmacophore template.

Cell Cycle↗

PubMed2000

Purification and characterization of dissimilatory nitrate reductase from a denitrifying halophilic archaeon, Haloarcula marismortui.

Dissimilatory nitrate reductase was purified from a denitrifying halophilic archaeon, Haloarcula marismortui, to an electrophoretically homogeneous state. The purified enzyme was inferred to be a homotetramer composed of a 63 kDa polypeptide. The electron paramagnetic resonance spectrum of the purified enzyme revealed typical rhombic signals which were ascribed to Mo(V) in the Mo-molybdopterin complex. Like the bacterial membrane-bound (Nar-) enzyme, the purified enzyme supported the catalysis of chlorate. The enzyme was activated in extreme saline conditions and the values of k(cat) and K(m) toward nitrate were 145 s(-1) and 79 microM, respectively, in the presence of 2.0 M NaCl.

Bacteria↗

PubMed2000

In vitro antiviral activity of lactoferrin and ribavirin upon hantavirus.

Bovine lactoferrin (LF) and ribavirin (Rbv) were tested as antiviral agents against Seoul type hantavirus (SR-11 strain) in vitro. Hantaviral foci number in Vero E6 cells infected with SR-11 was reduced with LF treatment by 5 days post infection to obtain a 50% effective dose (ED50) of 2500 microg/ml, while pretreatment with LF was highly efficacious having an ED50 of 39 microg/ml. Conversely, 1 h pretreatment with Rbv revealed no inhibition of viral focus formation but could significantly reduce the number of viral foci (ED50: 10 microg/ml) when used from the time of viral infection. One hour pre-treatment of the cell monolayer with LF and subsequent addition of Rbv revealed a synergistic anti-hantaviral effect against SR-11, <20 FFU/ml as compared to 10(5) foci/ml in the control. One hour treatment of SR-11 with LF prior to cell inoculation gave an ED50 of 312.5 microg/ml. Whereas, washing the LF-pretreated cell monolayer with PBS demonstrated minimal focus reduction, suggesting LF lightly adheres to cells. These results indicate that LF has anti-hantaviral activity in vitro and inhibition of virus adsorption to cells which play an important role in revealing the anti-hantaviral activity of LF. This paper reports for the first time the anti-hantaviral effect of LF.

Animals↗

PubMed2000

Detection of hantaviral antibodies among patients with hepatitis of unknown etiology in Japan.

Hantaviral antibodies were detected in the sera from patients with hepatic disease of unknown etiology in Japan by several different serological diagnostic methods. A total of 105 sera from diseased patients which were negative to A-G hepatitis virus infections in the Tokyo area were tested. Among them, 3 out of 73 sera from patients with chronic hepatic disease were positive to hantaviral antibody by enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescent antibody assay (IFA) and Western blot analysis (WB). Neutralizing antibody titers of the 3 sera to Seoul virus (SEO) were 4 to 8 times higher than those to Hantaan virus (HTN). However, all of the 32 sera from patients with acute hepatitis were negative for hantaviral antibody. Among the 60 patients with chronic hepatitis in Hokkaido which were serologically negative to B and C hepatitis virus infection, one was positive for hantaviral antibody by ELISA and WB. In contrast, the sera from healthy adults in Japan, 550 from the Honshu and Kyushu regions, and 1,000 from the Hokkaido region, were negative for hantavirus antibody. These results show that hantaviral antibodies are more frequently detected in patients with hepatic disease than in healthy adults. However, the observation that no positive sera were detected from patients with acute hepatitis implies that hantavirus might not be directly related to hepatitis.

Acute Disease↗

PubMed2000

Pathogenicity of Hantaan virus in newborn mice: genetic reassortant study demonstrating that a single amino acid change in glycoprotein G1 is related to virulence.

Two Hantaan virus strains, clone 1 (cl-1), which is virulent in newborn mice, and its attenuated mutant (mu11E10), were used to examine the pathogenesis of Hantaan virus infection in a mouse model and identify virus factors relating to virulence. After subcutaneous inoculation of newborn BALB/c mice, cl-1 caused fatal disease with high viral multiplication in peripheral organs, but mu11E10 produced nonfatal infection with a low level of virus multiplication. Intracerebral inoculation of either strain caused fatal disease. Histopathological changes in the dead animals were prominent in the brain, indicating that the brain is the target organ and produces the fatal outcome. These results indicate that mu11E10 has a generally less virulent phenotype, and because of decreased multiplication in peripheral tissues, neuroinvasiveness is also decreased. An experiment with genetic reassortant viruses showed that in newborn mice the M segment is the most related to virulence and the L segment is partly related. Sequence comparison detected a single deduced amino acid change (cl-1 Ile to mu11E10 Thr) at amino acid number 515 in glycoprotein G1. One nucleotide change, but no amino acid substitution, was observed in the noncoding region of the L segment. In mouse brain microvascular endothelial cells in vitro, viruses possessing a cl-1-derived M segment grew more rapidly than viruses containing a mu11E10-derived M segment. These results suggest that the single amino acid change in the glycoprotein alters peripheral growth, which affects invasion of the central nervous system in mice.

Amino Acid Substitution↗

PubMed2000

Luminacins: a family of capillary tube formation inhibitors from Streptomyces sp. II. Biological activities.

Twelve of the fourteen isolated components of the luminacin family were assayed for activity to inhibit capillary tube formation in vitro. Seven of them showed potent activity with IC50 values of less than 0.1 microg/ml in a rat aorta matrix culture model. Luminacin D, the strongest inhibitor, inhibited both endothelial cell proliferation and capillary tube formation. Morphological observation suggested that luminacin D inhibited the rearrangement of endothelial cells in the initial stage of tube formation. Luminacins and their derivatives are good candidates for application as angiogenesis inhibitors with a novel mechanism of action.

Angiogenesis Inhibitors↗

PubMed2000

[Characteristics of Papaver somniferum L. cv. ikkanshu cultivated in Izu].

The seeds of Papaver somniferum L. cv. Ikkanshu were sown in November (Autumn sowing: AS) and March (Spring sowing: SS) in a field at Izu Experimental Station for Medicinal Plants of National Institute of Health Sciencs, and both AS and SS plants were cultivated to investigate their growth, opium yield and alkaloid content in the opium. Growing periods from the sowing to the opium harvest were approximately six months for AS plants and three months for SS plants. Sizes of plants and capsules in AS were bigger than those in SS, reflecting their growth period. Opium yields per an are in AS and SS were 212.09 g and 142.03 g, respectively. The opium was able to be collected four times in the AS plants though the SS plants ceased to exude opium after the second incision. Therefore higher yield of opium in AS plants seems to be attributed to an amount of opium in the third and fourth incision. Average morphine content in the total opium was 15.61% in AS plants and 15.04% in SS plants, and the estimated amounts of morphine per an are in AS and SS plants were 33.16 g and 21.38 g, respectively.

Government Agencies↗

PubMed1999

Discovery of novel antitumor sulfonamides targeting G1 phase of the cell cycle.

Described herein is the discovery of a novel series of antitumor sulfonamides targeting G1 phase of the cell cycle. Cell cycle control in G1 phase has attracted considerable attention in recent cancer research, because many of the important proteins involved in G1 progression or G1/S transition have been found to play a crucial role in proliferation, differentiation, transformation, and programmed cell death (apoptosis). We previously reported our first antitumor sulfonamide E7010 as a novel tubulin polymerization inhibitor. Interestingly enough, continuous research on structurally related compounds led us to the finding of another class of antitumor sulfonamides that block cell cycle progression of P388 murine leukemia cells in G1 phase, but not in M phase. Of the compounds examined, N-(3-chloro-7-indolyl)-1,4-benzenedisulfonamide (E7070) showed significant antitumor activity against HCT116 human colon carcinoma both in vitro (IC(50) 0.11 microg/mL in cell proliferation assay) and in vivo (not only growth suppression but also a marked reduction of tumor size in nude mice). Because of its promising efficacy against human tumor xenografts and its unique mode of action, E7070 is currently undergoing phase I clinical trials in European countries.

Animals↗

PubMed1999

Rapid development of hepatic metastasis with high incidence following orthotopic transplantation of murine colon 38 carcinoma as intact tissue in syngeneic C57BL/6 mice.

BACKGROUND AND OBJECTIVES: Orthotopic transplantation of human colon tumors was a useful method for producing hepatic metastasis in mice. In many cases, however, it took about 3 months for evaluation. We examined an in vivo model of hepatic metastasis for only 4 weeks by conducting orthotopic transplantation of murine Colon 38 tumor using intact tissue in syngeneic mice and determined the efficacy of chemotherapeutic agents against hepatic metastasis. METHODS: Twenty milligrams of tumor tissues were prepared from subcutaneously (s.c.) growing Colon 38 tumor and orthotopically transplanted on the cecum in C57BL/6 mice. Mice were autopsied about 4 weeks after transplantation. Metastases to various organs were detected macroscopically or histochemically and tumor invasion into the cecum was observed histochemically. In experimental chemotherapy, mice bearing orthotopically transplanted Colon 38 tumor were separated into three equal groups and were either treated with fluorouracil or cisplatin (CDDP), or untreated. Four weeks after transplantation, activities of both agents against local tumor growth and hepatic metastasis were evaluated. RESULTS: Macroscopic metastases to various organs including the liver, the lung, and the peritoneum were developed during days 28 to 32 after inoculation. The frequency of hepatic metastasis was 96% (N = 23). Histological examination indicated that the local tumor invaded various layers of the cecum and metastasized to the liver and lung hematogenously. In experimental chemotherapy with fluorouracil and CDDP, only fluorouracil decreased the incidence of mice with hepatic metastasis (2/8 cases), compared with vehicle treatment (7/8 cases) and the number of metastatic nodules in the liver (P = 0.016), although the inhibition against local growth of CDDP in T/C [45%; mean tumor weight of the test group (T) compared with that of the control group (C)] was similar to that of fluorouracil (53%). CONCLUSIONS: This model, with its rapid development of hepatic metastasis in high frequency, should be useful as a screening assay to find anti-metastatic agents for colorectal carcinoma.

Adenocarcinoma↗

PubMed1999

N-acetylgalactosamine (GalNAc)-specific lectins mediate enhancement of Hantaan virus infection.

Summary. N-acetylgalactosamine (GalNAc)-specific lectins, Dolichos biflorus agglutinin (DBA), and soybean agglutinin (SBA), enhanced Hantaan (HTN) virus infections in Vero E6 and P388D1 cells. Treatment of Vero E6 cells with the lectins either before or during, but not after, virus inoculation resulted in lectin-mediated enhancement of infection (LME), indicating that GalNAc-specific lectin affects an early stage of the infection. Lectin blot and FACS analysis showed that the ability of HTN virus envelope glycoproteins and cell surface molecules to bind DBA and SBA was essential for LME. GalNAc clearly inhibited LME, indicating that the lectins bind with their specific carbohydrate-binding site. These results suggest that a lectin cross-link between the virus and the cell surface is the most plausible mechanism for inducing infection enhancement.

Acetylgalactosamine↗

PubMed1999

Genetic diversities of hantaviruses among rodents in Hokkaido, Japan and Far East Russia.

Seroepizootiologic surveys among wild rodents were carried out in Japan and Far East Russia in 1995 and 1996. Seropositive animals were only identified in Clethrionomys rufocanus (23/134) in Hokkaido, Japan. On the other hand, seropositives were identified in C. rufocanus (1/8), Apodemus agrarius (2/66), Apodemus spp. (2/26) and Microtus fortis (3/22) in Vladivostok, Far East Russia. Total RNA was isolated from lungs of seropositive animals and the S genome segments were amplified by PCR, cloned and sequenced. The S and M genomes of hantavirus, derived from Japanese C. rufocanus (Tobetsu genotype), were most closely related with Puumala viruses (76-79% nucleotide and 95% amino acid identities for S genome, 70-78% nucleotide and 87-92% amino acid identities for M genome). The recombinant nucleocapsid protein of Tobetsu genotype was antigenically quite similar with that of Sotkamo. These suggest that the virus endemic in Japanese C. rufocanus belongs to Puumala virus. Phylogenetic analysis indicates that the genotype forms a distinct lineage within Puumala viruses. Partial S segment (1-1251 nt), derived from seropositive M. fortis in Vladivostok, was sequenced and analyzed. The S genome segment, which was designated Vladivostok genotype, was most closely related with Khabarovsk virus (79% nucleotide and 90% amino acid identities) which was isolated from M. fortis.

Animals↗

PubMed1999

Iron reductase for magnetite synthesis in the magnetotactic bacterium Magnetospirillum magnetotacticum.

Ferric iron reductase was purified from magnetotactic bacterium Magnetospirillum (formerly Aquaspirillum) magnetotacticum (ATCC 31632) to an electrophoretically homogeneous state. The enzyme was loosely bound on the cytoplasmic face of the cytoplasmic membrane and was found more frequently in magnetic cells than in nonmagnetic cells. The molecular mass of the purified enzyme was calculated upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be about 36 kDa, almost the same as that calibrated by gel filtration analysis. The enzyme required NADH and flavin mononucleotide (FMN) as optimal electron donor and cofactor, respectively, and the activity was strongly inhibited by Zn2+ acting as a partial mixed-type inhibitor. The Km values for NADH and FMN were 4.3 and 0. 035 microM, respectively, and the Ki values for Zn2+ were 19.2 and 23.9 microM for NADH and FMN, respectively. When the bacterium was grown in the presence of ZnSO4, the magnetosome number in the cells and the ferric iron reductase activity declined in parallel with an increase in the ZnSO4 concentration of the medium, suggesting that the ferric iron reductase purified in the present study may participate in magnetite synthesis.

FMN Reductase↗