Biomedical subjects

H Tsujimoto

Publications and source records attributed to H Tsujimoto.

At least 199 records · Page 11Linked to original sources

PubMed1994

Inhibition of gastric cancer cell proliferation by antisense oligonucleotides targeting the messenger RNA encoding proliferating cell nuclear antigen.

Proliferating cell nuclear antigen (PCNA) is a nuclear protein that regulates DNA synthesis by DNA polymerase delta, and is essential for DNA replication. PCNA expression level is related to the malignancy of gastric cancer cells. Seven different gastric cancer cell lines and two kinds of control cell lines were treated with antisense oligonucleotides complementary to the messenger RNA of PCNA. Treatment of each gastric cancer cell line with antisense oligonucleotides at concentration of 10-40 microM inhibited the cell growth, colony formation and PCNA protein production in a dose-dependent manner, but only affected normal cells slightly. A random sequence oligomer showed no effect. These results show that PCNA is essential for gastric cancer cell proliferation and that the use of synthetic oligonucleotides is an effective way of producing antisense-mediated changes in the behaviour of human gastric cancers.

Base Sequence↗

PubMed1994

Selective delivery of a greater amount of methotrexate to regional lymph nodes using a new dosage formulation, methotrexate adsorbed on activated carbon particles, in rats.

A new dosage formulation (MTX-CH) comprising methotrexate (MTX) adsorbed onto a suspension of activated carbon particles was developed for the treatment of lymph node metastases. In vitro studies showed that activated carbon particles adsorbed a great amount of MTX. Subcutaneous injection of MTX-CH into the left hind foot pad of rats distributed a greater amount of MTX selectively to the regional lymph nodes (the left popliteal node and the para-aortic nodes) for a longer period of time than similar administration of MTX aqueous solution with a smaller amount of MTX distributed to the rest of the whole body.

Adsorption↗

PubMed1994

Burkholderia (formerly Pseudomonas) cepacia porin is an oligomer composed of two component proteins.

The 81 kDa protein (designated OpcPO) which forms a diffusion pore in the outer membrane of Burkholderia (formerly Pseudomonas) cepacia has a unique characteristic in that when the purified protein is heated it yields a major 36 kDa protein (designated OpcP1) and a minor 27 kDa protein (designated OpcP2). Moreover, incubation of OpcPO in citrate buffer at pH 3.0 produced an unusual dissociation into 72 kDa and 27 kDa proteins. For the characterization of OpcPO and its derivatives, OpcP1 and OpcP2 from purified OpcPO were isolated by preparative SDS-PAGE. Reconstitution of OpcPO using purified preparations of OpcP1 and OpcP2 indicated that these derivatives were not proteolytic fragments of OpcPO. Moreover, immunoblot assays with murine polyclonal antisera specific for OpcP1 and OpcP2 yielded the following results: (i) OpcP1 and OpcP2 are immunologically distinguishable proteins; (ii) the unusual dissociation of OpcPO in citrate buffer at pH 3.0 resulted in the release of OpcP2 from OpcPO, and the resulting 72 kDa protein was probably an oligomer of OpcP1; (iii) purified OpcP1 itself produced two additional 53 kDa and 72 kDa proteins spontaneously following elution from the bottom of the SDS-PAGE gel. From these findings, it was concluded that OpcPO is formed by the non-covalent association of OpcP2 with an oligomer of OpcP1 that has the ability to self-assemble.

Antibodies, Bacterial↗

PubMed1994

Genetic determinants of feline leukemia virus-induced lymphoid tumors: patterns of proviral insertion and gene rearrangement.

The genetic basis of feline leukemia virus (FeLV)-induced lymphoma was investigated in a series of 63 lymphoid tumors and tumor cell lines of presumptive T-cell origin. These were examined for virus-induced rearrangements of the c-myc, flvi-2 (bmi-1), fit-1, and pim-1 loci, for T-cell receptor (TCR) gene rearrangements, and for the presence of env recombinant FeLV (FeLV-B). The myc locus was most frequently affected in naturally occurring lymphomas (32%; n = 38) either by transduction (21%) or by proviral insertion (11%). Proviral insertions were also common at flvi-2 (24%). The two other loci were occupied in a smaller number of the naturally occurring tumors (fit-1, 8%; pim-1, 5%). Examination of the entire set of tumors showed that significant numbers were affected at two (19%) or three (5%) of the loci. Occupation of the fit-1 locus was observed most frequently in tumors induced by FeLV-myc strains, while flvi-2 insertions occurred with similar frequency in the presence or absence of obvious c-myc activation. These results suggest a hierarchy of mutational events in the genesis of feline T-cell lymphomas by FeLV and implicate insertion at fit-1 as a late progression step. The strongest links observed were with T-cell development, as monitored by rearrangement status of the TCR beta-chain gene, which was positively associated with activation of myc (P < 0.001), and with proviral insertion at flvi-2 (P = 0.02). This analysis also revealed a genetically distinct subset of thymic lymphomas with unrearranged TCR beta-chain genes in which the known target loci were involved very infrequently. The presence of env recombinant FeLV (FeLV-B) showed a negative correlation with proviral insertion at fit-1, possibly due to the rapid onset of these tumors. These results shed further light on the multistep process of FeLV leukemogenesis and the relationships between lymphoid cell maturation and susceptibility to FeLV transformation.

Animals↗

PubMed1994

[The prevention of peritoneal dissemination of gastric cancer with intraperitoneal activated carbon particles absorbing mitomycin C].

A new drug dosage form comprising activated carbon particles absorbing mitomycin C (MMC-CH) has the advantage of being retained in the peritoneal cavity and distributes a larger amount of mitomycin C for a long time. Some 113 patients with gastric cancer and serosal infiltration were randomly assigned intraperitoneal treatment with MMC-CH and no anti-cancer drugs. There were significant differences in survival rate between the patients who have no visible peritoneal dissemination with MMC-CH and without. Thus, intraoperative intraperitoneal treatment with MMC-CH improves survival after gastrectomy for gastric cancer and seems effective against peritoneal recurrence.

Absorption↗

PubMed1993

cDNA nucleotide sequence and primary structure of mouse uterine peptidylarginine deiminase. Detection of a 3'-untranslated nucleotide sequence common to the mRNA of transiently expressed genes and rapid turnover of this enzyme's mRNA in the estrous cycle.

Peptidylarginine deiminase is a protein-modulating enzyme which converts the arginine residues in proteins to citrulline residues. This study describes the complete primary structure of mouse peptidylarginine deiminase, which was deduced from nucleotide sequence analysis of cDNA clones plus proteochemical analysis of the purified enzyme. The composite cDNA sequence contained a 5' untranslated region of 7 bases, an open reading frame of 2019 bases that encoded 673 amino acids, a 3' untranslated region of 2662 bases, and part of a poly(A) tail. The N-terminal and C-terminal sequences of the enzyme matched the sequences deduced from nucleotide analysis. Furthermore, we determined that the N-terminal sequence was N alpha-acetyl-Met-Gln-, a sequence which has never previously been reported among N alpha-acetyl-Met proteins. The Arg 352 of the enzyme was converted to a citrulline residue and the potential Asn-linked glycosylation site (Asn542-Glu543-Ser544) had no carbohydrate moiety. Thus, mouse peptidylarginine deiminase consists of 673 amino acids with a molecular mass of 76,260. Mouse peptidylarginine deiminase mRNA has two AU-rich structures in the 3' untranslated region which exhibit a high degree of similarity to those in lymphokine, cytokine and proto-oncogene mRNA species. Since the rat enzyme (previously reported) does not possess these characteristic structures, we compared the levels of enzyme activity and mRNA in the mouse and rat uterus at four defined phases of the estrous cycle. The degradation of peptidylarginine deiminase and its mRNA proceeded significantly faster in the mouse than in the rat. We speculate that the unusual structure of the mouse enzyme and its mRNA be involved in this species-specific rapid degradation.

Amino Acid Sequence↗

PubMed1993

Milky spots as the implantation site for malignant cells in peritoneal dissemination in mice.

We examined the site-specific implantation of cancer cells in peritoneal tissues after an i.p. inoculation of 10(5) P388 leukemia cells. Twenty-four h after the inoculation, the number of viable cancer cells infiltrating into specific tissue sites of the peritoneum was estimated by an i.p. transfer method. A descending order of tissue implantation with cancer cells was established as omentum > gonadal fat > mesenterium > posterior abdominal wall > stomach, liver, intestine, anterior abdominal wall, and lung. A significant correlation was established between the logarithm of the number of infiltrating cancer cells and the logarithm of the number of milky spots. Next, the omentum was examined microscopically after i.p. inoculation with P388 leukemia cells labeled with bromodeoxyuridine or B-16 PC melanoma, which were differentiated from the other cells by an immunocytological method using anti-bromodeoxyuridine antibody or by the melanin of the B-16 PC melanoma cells. These cancer cells were found microscopically to be infiltrating only the milky spots, whereas none were seen at the other sites. These results suggest that cancer cells seeded i.p. specifically infiltrate the milky spots in the early stage of peritoneal metastases.

Animals↗

PubMed1993

A common proviral integration region, fit-1, in T-cell tumors induced by myc-containing feline leukemia viruses.

Feline leukemia viruses carrying transduced v-myc genes (myc-FeLV) induce tumors of clonal origin, suggesting that activated myc alone is not sufficient for tumorigenesis. To investigate the hypothesis that insertional mutagenesis plays a role by activating genes which collaborate with v-myc, we looked for evidence of common proviral integration sites in these tumors. By inverse polymerase chain reaction we identified a 6-kb domain, designated fit-1, in which FeLV proviruses were inserted in four of nine (44%) T-cell tumors induced by myc-FeLV. The fit-1 locus was mapped to feline chromosome B2 and appears to be distinct from known oncogenes located on this chromosome. Fit-1 represents a novel common proviral integration region which may harbor a cellular gene which acts in concert with the myc gene in T-cell tumorigenesis.

Animals↗

PubMed1993

Effects of sialoadenectomy and epidermal growth factor administration on 9,10-dimethyl-1,2-benzanthracene-induced tumor formation in hamster cheek pouch.

The effects of removal of the submandibular gland (sialoadenectomy) and administration of human urinary epidermal growth factor on the 9,10-dimethyl-1,2-benzanthracene-induced tumor formation were investigated with the use of a hamster cheek pouch model. Syrian hamsters were treated with 0.5% 9,10-dimethyl-1,2-benzanthracene for 6 weeks. Thereafter hamsters in group 1 underwent a sham operation and those in groups 2 and 3 underwent a sialoadenectomy. Subsequently, hamsters in groups 1 and 2 were given 0.9% sodium chloride and group 3 received the human urinary epidermal growth factor at a dose of 0.25 mg/kg body weight subcutaneously three times a week for 8 weeks. Sixteen weeks after the start of the experiment, the mean number of tumors that were less than 3-mm in diameter in groups 1 and 3 was significantly greater than that in group 2 (p < 0.05). The overall incidence and mean number of all carcinomas irrespective of size showed no differences among the experimental groups. These results indicate that epidermal growth factor synthesized in the submandibular gland may enhance the induction of cheek pouch tumor.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1993

Enhancement of various non-specific immune effector functions in mice by local injection of aclacinomycin A adsorbed onto activated carbon particles (ACR-CH).

Local injections of aclacinomycin A adsorbed onto activated carbon particles (ACR-CH) augmented the cytotoxic activities of regional lymph node cells for 7 days. In contrast NK-activity was only slightly augmented by injections of aclacinomycin A (ACR) solution or activated carbon suspension. The effects were found in lymphocytes from all regions tested. NK-activity could only be detected when both adherent and non-adherent cells were present. The cell number of L3T4+ cells in each type of lymph node tested increased, and subset analysis of the lymphocyte subpopulations revealed an increase in the ratio of L3T4+/Lyt2+ cells, suggesting that the ACR-CH selectively increased and stimulated L3T4+ cells. Enhanced capacity of lymph node cells to produce cytokines, tumor necrosis factor (TNF) and interleukin-1 (IL-1) upon restimulation (with LPS) in vitro in the ACR-CH treated group was found. From these results, it appears that the new dosage form of aclacinomycin A, ACR-CH, with superior therapeutic efficacy against lymph node metastases, can also enhance the immune response of regional lymph node cells. The findings reported here will be valuable in the establishment of novel chemoimmunotherapeutic protocols using ACR-CH.

Aclarubicin↗

PubMed1993

Detection of feline immunodeficiency virus proviral DNA in feline peripheral blood mononuclear cells by the nested two-step polymerase chain reaction.

The polymerase chain reaction (PCR) was applied to detect feline immunodeficiency virus (FIV) proviral DNAs in primary peripheral blood mononuclear cells (PBMC). Suitable conditions for PCR amplification were examined to obtain highly sensitive and specific results by simple staining in agarose gel. Specific amplification of FIV proviral DNA in PBMC DNA of FIV-infected cats was achieved by a nested two-step PCR that amplified the DNA first with outer primers and then with inner primers nested within the first primers. PCR amplification using different primers indicated that those based on the gag sequence of the FIV/TM2 strain isolated in Japan were suitable for the detection of FIV genomes in naturally infected Japanese pet cats. By the nested two-step PCR with mixed gag primers of TM2 and Petaluma, isolated in the USA, we could detect FIV genomes in all 11 primary PBMC samples from FIV-seropositive cats tested. The PCR protocol developed here is sensitive and specific for molecular detection of FIV infection in cats.

Animals↗

PubMed1993

Cisplatin microcrystals suspended in oil--toxicity in mice.

A new dosage format, cisplatin microcrystals suspended in oil (CDDP-oil), was developed for the treatment of peritoneal carcinomatoses. We studied the acute toxicity of CDDP-oil injected intraperitoneally in mice. The 50% lethal dose was 30.3 mg/kg (27.1-33.7 mg/kg at the 95% confidence level), which was 1.79 times that of a cisplatin aqueous solution (CDDP-sol) of 16.9 mg/kg (16.1-17.8 mg/kg at the 95% confidence level). There were no significant differences in the duration of the toxic effects and the toxic symptoms between these two dosage forms. However, the severity of weight loss in the group given CDDP-oil was less than the group given CDDP-sol.

Animals↗

PubMed1993

Enhancement of LAK-like activity and cytokine induction in regional lymph nodes and spleen cells of mice after intralymphnodal injection of OK-432, a killed streptococcal preparation.

A single dose of inactivated streptococci (OK-432) was injected into the popliteal lymph nodes of male CDF1 mice and its effects on popliteal, inguinal, and para-aortic lymph node cells and spleen cells were investigated and compared with the effects of subcutaneous injections of the same dosage of OK-432. Regional lymph node cells and spleen cells obtained from intralymphnodally injected mice lysed not only natural killer (NK)-sensitive YAC-1 cells, but also NK-resistant P-815 and meth-A cells. Lysis of target cells was inhibited when effector cells were treated with anti-Thy-1.2 or anti-Lyt-2.2 monoclonal antibody and complement, but no inhibition was apparent after treatment with anti-asialo-GM1 or anti-Lyt-1.2 antibody and complement. These results suggest that the effector cells are lymphocyte-activated killer (LAK) cells. An enhanced capacity of lymph node cells to produce cytokines, tumor necrosis factor and interleukin 1 upon restimulation with lipopolysaccharide was found only in intralymphnodally injected mice. Thus, the induction of LAK-like cells and cytokine production in regional lymph nodes and spleen cells by the intralymphnodal administration of OK-432 should be effective for the inhibition or treatment of lymph node metastases.

Animals↗

PubMed1993

Apoptosis induced by tumor necrosis factor in cells chronically infected with feline immunodeficiency virus.

Tumor necrosis factor alpha (TNF-alpha) induced morphologic changes such as chromatin condensation and cell shrinkage in a feline fibroblastic cell line (CRFK) chronically infected with feline immunodeficiency virus (FIV) but not in uninfected CRFK cells. DNA extracted from TNF-alpha-treated CRFK cells infected with FIV showed a ladder of nucleosomal DNA, indicating that this cytocidal effect by TNF-alpha was due to programmed cell death, or apoptosis. These findings may have implications for understanding the pathogenesis of FIV infection and for the design of specific therapeutic strategies for AIDS in humans as well as cats.

Animals↗

PubMed1993

Malignant histiocytosis with multiple skin lesions in a dog.

A 7-year-old male Yorkshire terrier was examined for multiple plaques and nodules on the skin. The clinical, cytological and histopathological features indicated a malignant histiocytosis. Cytoreductive chemotherapy produced moderate clinical improvement, but died at day 90 after the first admission. Pathological examination revealed the neoplastic histiocytes in the skin as well as in the myocardium and skeletal muscles.

Animals↗

PubMed1993

Rearrangements of immunoglobulin and T-cell receptor genes in canine lymphoma/leukemia cells.

Tumor cells from 15 canine lymphoma/leukemia cases were examined for genetic rearrangements of immunoglobulin and T-cell receptor (TCR) genes in parallel with cell surface antigens. Ten of these 15 cases showed rearrangements of the immunoglobulin heavy chain (IgH) gene, while 4 cases displayed TCR beta-chain gene rearrangements on Southern blot analysis. All the cases with IgH gene rearrangements had multicentric form lymphoma, and 6 of the 10 cases were cell surface immunoglobulin-positive. On the other hand, the cases with TCR gene rearrangements included atypical lymphoma/leukemia cases, and 3 of the 4 cases were Thy-1 antigen-positive. Although the tumor cell lineage of a considerable number of lymphoma/leukemia cases could not be determined by phenotypic analysis, examination of the IgH and TCR gene rearrangements disclosed the lineages of 14 of 15 cases. Genetic analysis demonstrated that the tumor cells in most canine multicentric lymphomas were formed by clonal expansion of B-lymphocyte. These findings show that studies on the rearrangements of immunoglobulin and TCR genes are very useful for understanding the cellular origin, clonality and hierarchy of canine lymphoma/leukemia cells.

Animals↗

PubMed1993

Molecular cloning and chromosomal mapping of feline p53 tumor suppressor gene.

Alterations of the p53 tumor suppressor gene have been observed in a variety of human and mouse tumors. For investigation of the role of this gene in tumors in cats, feline p53 cDNA was molecularly cloned by PCR amplifications using primers based on the sequences conserved among several species. The cloned cDNA appeared to cover approximately 90% of the open reading frame of the feline p53 gene and had characteristic structures in common with the p53 genes of several other species. The amino acid sequence similarities of the feline p53 with the human, mouse, rat and chicken counterparts were 82.9%, 75.6%, 76.5% and 57.2% respectively. Moreover, using a panel of feline x rodent somatic cell hybrids, the feline p53 gene was assigned to feline chromosome E1. These data will be useful for determining the role of the p53 tumor suppressor gene in feline tumors.

Amino Acid Sequence↗

PubMed1993

Establishment and characterization of a feline large granular lymphoma cell line expressing interleukin 2 receptor alpha-chain.

A feline large granular lymphocyte (LGL) cell line was established from a cat with an alimentary-form lymphoma. This cell line, designated as FGL, had many large azurophilic granules in the cytoplasm, which were typical to LGL cells. Proviral genome of feline leukemia virus was detected in the chromosomal DNA of FGL cells, and reverse transcriptase activity was also demonstrated in the culture supernatant. Furthermore, we found expression of interleukin 2 (IL-2) receptor alpha-chain on the cell surface of FGL and its natural killer activity against human erythroblastic leukemia cell line, K562.

Animals↗