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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 163 records · Page 9Linked to original sources
PubMed2000

The possible role of c-fos expression in rheumatoid cartilage destruction.

OBJECTIVE: To determine the effect of c-fos on human chondrocytes and to examine the role of c-fos in cartilage destruction in rheumatoid arthritis (RA). METHODS: We examined changes in collagen synthesis by transfecting human c-fos into cultured human chondrocytes and evaluated expression of c-fos mRNA and localization of Type II collagen, matrix metalloproteinases-1 (MMP-1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) in articular cartilage samples from patients with RA or osteoarthritis (OA) by in situ hybridization and immunohistochemistry. RESULTS: Introduction of c-fos in the chondrocytes decreased endogenous transcription of Type II collagen and TIMP-1, and increased that of MMP-1. The effect of the activating protein-1 protein on the MMP-1 and TIMP-1 promoters in human articular chondrocytes was analyzed by chloramphenicol acetyltransferase activity assay. MMP-1 promoter was clearly activated by Jun related proteins as well as Fos/Jun related protein heterocomplex. On the other hand, c-fos combined with any of the Jun related proteins failed to stimulate the TIMP-1 promoter, although it was activated by Fra-1 or Fra-2/Jun related protein heterocomplexes. Expression of c-fos mRNA was detected in chondrocytes in the mid and deep layers of cartilage in 11/15 patients (73%) with RA, but only in the superficial layer of cartilage from 2/10 patients (20%) with OA. Although TIMP-1 staining exceeded that of MMP-1 in OA cartilage, it appeared to be less intense than MMP-1 staining in RA cartilage. CONCLUSION: These results suggest that activation of c-fos may be involved in cartilage metabolism and hence play a crucial role in the pathogenesis of arthritic destruction in RA.

Adult↗
PubMed2000

[The role of daunorubicin in induction therapy for adult acute myeloid leukemia].

The relationship between the total dose of daunorubicin (DNR) in induction therapy and the treatment outcome were evaluated based upon individualized doses of DNR during induction therapy for patients with acute myeloid leukemia(AML). Ninety-two previously untreated adult AML patients admitted to our hospital were analyzed for the dose of DNR required for complete remission (CR), the CR rate, disease-free survival (DFS) and overall survival (OS). The induction therapy consisted of DNR (40 mg/m2/d, i.v., from D 1 until the marrow was hypoplastic), Ara-C, prednisolone, and/or 6-thioguanine. Eighty-three out of 92 patients were assessable. Sixty-three patients entered CR (76%), of whom 52 attained CR with the first course of induction therapy. The 10-year DFS and OS rates were 31.2% and 42.3%, respectively. The median total dose of DNR in the induction therapy was 280 mg/m2 (120-480 mg/m2), which was not influenced by initial WBC count, or FAB type. These results indicate that when the dose is linked to the observed tumor response, the optimal dose of DNR in the induction therapy is around 280 mg/m2 (40 mg/m2 x 7 times), which is higher than the conventional dose of 40-60 mg/m2 for 3 days. The higher dose of DNR in the induction therapy for adult AML should be selected when the feasibility of a new drug is evaluated in a randomized trial.

Adolescent↗
PubMed2000

Effect of prostaglandin E1 on vascular endothelial growth factor production by human macrophages and colon cancer cells.

We previously demonstrated that cyclooxygenase-2 (COX-2) was predominantly expressed in macrophages of sporadic human colonic adenomas; however, the role of COX-2-expressing cells during colon carcinogenesis has not yet been elucidated. In the present study, we showed the effect of PGE, on vascular endothelial growth factor (VEGF) production by PMA-differentiated U937 cells, a human macrophage model (H-Mac), and by human colon cancer cells T84. PGE1 dramatically induced VEGF production by H-Mac, but not that by T84. PGE1 significantly increased intracellular cAMP formation by H-Mac, but only modestly increased that by T84. 8-bromo-cAMP and cholera toxin also increased VEGF production by H-Mac. In contrast, neither of these agents modulated VEGF production by T84. EP2 and EP4 (PGE specific receptors) mRNA was expressed in both cells. PG dramatically increased VEGF production by activated macrophages, but not by cancer cells, through a specific PGE receptor-mediated process. These findings suggest that PGs produced by COX-2-expressing macrophages induce VEGF production by macrophages, but not by cancer cells, in an autocrine fashion.

Adjuvants, Immunologic↗
PubMed2000

[CD8-positive diffuse large B-cell lymphoma].

In May, 1998, a 63-year-old woman was admitted for treatment of relapsed malignant lymphoma. In March 1997, a diagnosis of diffuse large B-cell lymphoma(DLBL), clinical stage IIISE A, was made from a biopsy specimen of the tumor in the left buccal mucosa. Six cycles of CHOP regimen were given, and complete remission was achieved. However, relapse of the lymphoma was suspected, and the patient was transferred to our hospital. On admission, a right tosillar mass, 8 mm in diameter, was found, and a biopsy showed DLBL. The immunophenotype of the lymphoma cells was CD3- CD4- CD5- CD8+ CD10- CD19+ CD20+ CD23- CD25+ IgL (lambda)+, and dual staining confirmed that the cells were CD8+ and CD19+. The patient was an HTLV-1 carrier, but monoclonal integration of HTLV-1 proviral DNA into the lymphoma cells was not detected. She was diagnosed as having CD8+ DLBL, clinical stage IA. Because she responded to salvage chemotherapy, autologous peripheral blood stem cell transplantation was performed and complete remission was obtained. To our knowledge, this is the first report of CD8+ DLBL.

CD8 Antigens↗
PubMed2000

A decline in lower extremity lean body mass per body weight is characteristic of women with early phase osteoarthritis of the knee.

OBJECTIVE: Sarcopenia progresses with aging, but the effect of muscle loss on degenerative joint disorders has not been precisely evaluated. We assessed the distribution of lean body mass (LBM) in middle aged women who had osteoarthritis (OA) of the knee for < 5 years. METHODS: Two hundred thirty-five Japanese women aged 45-69 years, including 117 with knee OA for < 5 years, and 118 age and sex matched healthy controls were studied. Body composition measurements were carried out by segmental bioelectrical impedance using 8 surface electrodes. Anthropometric data consisting of LBM of upper extremities/body weight (U-LBM/W), LBM of trunk/body weight (T-LBM/W), and LBM of lower extremities/body weight (L-LBM/W) for knee OA participants were compared to corresponding data for controls. In the knee OA group, the significance of correlations between anthropometric data and Lequesne index of severity for knee OA and between anthropometric data and disease duration were assessed. RESULTS: L-LBM/W was significantly lower in knee OA participants compared with controls (19.2 +/- 2.7% vs 21.0 +/- 2.9%; p < 0.0001). However, no significant differences in U-LBM/W and T-LBM/W were observed between the knee OA and control groups (p > 0.2). L-LBM/W did not correlate significantly with the index of severity or disease duration (p > 0.2). CONCLUSION: Decline in L-LBM/W, but not U-LBM/W or T-LBM/W, may be important in the pathogenesis of knee OA.

Adipose Tissue↗
PubMed2000

[Cytomegalovirus mononucleosis with severe thrombocytopenia].

In October 1998, a 37-year-old man was admitted because of petechiae and thrombocytopenia following flu-like symptoms. On admission, there were numerous petechiae on the back and extremities. The WBC count was 3,700/microliter with 3% atypical lymphocytes, the lymphocyte CD4/CD8 ratio 0.37, and the platelet count 1,000/microliter. Mild splenomegaly was detected by CT. Results of blood chemistry and coagulation tests were normal. A bone marrow aspirate was normocellular with no signs of dysplasia, and the megakaryocyte count was normal. The patient was initially diagnosed as having virus infection-associated thrombocytopenia. Steroid therapy was started immediately, and the platelet count rose to 15 x 10(4)/microliter on day 21. The PA-IgG level was 652 ng/10(7) platelets. Mild liver dysfunction developed, and atypical lymphocytes increased in number thereafter. Because IgM anti-cytomegalovirus (CMV) antibody (Ab) was positive and IgG CMV Ab was negative, a diagnosis of CMV mononucleosis was made. Gancyclovir was therefore started. Four months later, steroid therapy was discontinued, and partial remission has since been maintained. In healthy individuals, CMV infection is usually latent, and the development of mononucleosis is rare. So far, 11 cases of CMV-induced mononucleosis associated with severe thrombocytopenia have been reported in immunocompetent adults.

Adult↗
PubMed2000

Colorectal cancer and non-steroidal anti-inflammatory drugs.

Non-steroidal anti-inflammatory drugs (NSAIDs) can prevent or reduce the occurrence of colorectal cancers. Anti-carcinogenic properties of NSAIDs have been demonstrated in epidemiological studies of humans and experimental animals. In addition, clinical studies of familial adenomatous polyposis and sporadic adenomas have demonstrated that NSAIDs induce regression of colorectal adenomas and prevent formation of these tumors. NSAIDs thus induce early disruption of the adenoma-carcinoma sequence and may mainly suppress subsequent cancer formation at adenoma stage. The mechanism of the anti-carcinogenic effect of these drugs is not known, but results of most studies support that cyclooxygenase-2 (an inducible isoform of prostaglandin synthetase, COX-2) is a major target of NSAIDs in this effect. Recent immunohistochemical studies have revealed that COX-2 is expressed not in tumor cells but in interstitial cells of colonic adenomas. Accordingly, NSAIDs may exhibit anti-carcinogenic property through the inhibition of prostaglandin production by COX-2 expressing interstitial cells. Future research should be focused on the role of prostaglandins in the interaction of tumor cells and interstitial cells in colon carcinogenesis.

Adenocarcinoma↗
PubMed1999

Differential subcellular distribution of neurolysin (EC 3.4.24.16) and thimet oligopeptidase (EC 3.4.24.15) in the rat brain.

Immunohistochemistry was used to analyze the rat brain distribution of thimet oligopeptidase and neurolysin. Both enzymes appear ubiquitously distributed within the entire rat brain. However, neuronal perikarya and processes stained for neurolysin, while intense nuclear labeling was only observed for thimet oligopeptidase. These data suggest that neurolysin and thimet oligopeptidase, endopeptidases sharing several functional and structural similarities, are present in distinctive intracellular compartments in neuronal cells.

Animals↗
PubMed1999

High expression of cyclooxygenase-2 in macrophages of human colonic adenoma.

Cyclooxygenase (COX)-2 is a possible molecular target for suppression of colon carcinogenesis by non-steroidal anti-inflammatory drugs (NSAIDs). However, the expression of COX-2 in human colonic tumors during the adenoma-carcinoma sequence has not been elucidated. In the present study, we examined immuno-histochemically the expression and localization of the COX-2 protein in human colonic adenomas and cancers. Twelve human colonic adenomas and 9 advanced cancers were studied. Immunoreactive COX-2 was predominantly and strongly expressed in sub-epithelial interstitial cells broadly present in the surface area of adenomas. The staining pattern of macrophages was similar to that observed for COX-2 in adenomas. Adjacent normal colonic mucosa was negative for COX-2 expression. In contrast, COX-2 was relatively weakly expressed in both tumor cells and interstitial cells in advanced colon cancers. In conclusion, the target of NSAIDs in preventing colon carcinogenesis may be the COX-2 expressed in interstitial cells, possibly macrophages, of colonic adenomas.

Adenoma↗
PubMed1999

Isolation and analysis of cDNA within a 300 kb Arabidopsis thaliana genomic region located around the 100 map unit of chromosome 1.

In order to analyze the organization of genes located at the 100 map unit of chromosome 1, we screened cDNAs hybridized with approximately 300kb contiguous DNA using four P1 clones and one YAC clone. A total of 40 kinds of cDNA were isolated, and their entire sequences were determined. A comparison with the GenBank/EMBL database indicated that three of the cDNAs have been found in Arabidopsis, and that similar sequences to 18 of the cDNAs had been detected in Arabidopsis or other organisms. cDNAs were aligned on a physical map of the contiguous DNA, and the transcriptional direction of each cDNA was determined. This contiguous DNA contains a large direct repeat, which contains five genes. In addition, identical or very similar sequences to two cDNAs are located in a narrow region. Thus, a total of 50 genes were identified, and the gene density was revealed to be approximately one gene every 6kb. In addition, cDNA sequencing revealed the existence of unusual transcripts. A sequence of seven cDNAs seemed to have no significant open reading frames. Furthermore, the existence of antisense RNA and the possibility of alternative splicing were also revealed.

Arabidopsis↗
PubMed1999

Role of primary constitutive phosphorylation of Sendai virus P and V proteins in viral replication and pathogenesis.

Functional analysis of the primary constitutive phosphorylation of Sendai virus P and V proteins was performed using both in vitro and in vivo systems. Sendai virus minigenome transcription and replication in transfected cells were not significantly affected in the presence of primary phosphorylation deficient P protein (S249A, S249D, P250A) as measured by either the luciferase activity or the Northern blot analysis. Similarly, recombinant Sendai viruses lacking the primary phosphorylation in P grew to titers close to the wild-type virus in cell cultures and in the natural host of Sendai virus, the mouse. Mutant viruses showed no altered pathogenesis in mice lungs. Oligomerization of P by binding WT P or mutant P to GST-P (WT) Sepharose beads revealed that the primary phosphorylation was not crucial for P protein oligomerization. Similar to P protein primary phosphorylation, the V protein primary phosphorylation at serine249 was not essential for minigenome transcription and replication, as both WT and mutant V proteins were found equally inhibitory to the minigenome replication. These results show that the primary phosphorylation of P protein has no essential role in Sendai virus transcription, replication, and pathogenesis.

Animals↗
PubMed1999

Double-layered membrane vesicles released from mammalian cells infected with Sendai virus expressing the matrix protein of vesicular stomatitis virus.

The matrix (M) protein of vesicular stomatitis virus (VSV) was reported to form vesicles on the cell surface and subsequently to be released into the cultured medium when expressed from cDNA by virus vectors. To further investigate VSV M activity, we generated a recombinant Sendai virus (SeV) expressing the VSV M protein (SeV-M(VSV)). When cells were infected with SeV-M(VSV), VSV M was found abundantly in the culture medium. Electron microscopy demonstrated the budding of two-membraned vesicles (>/= 0.8 microm in diameter) from the infected cells. The outer membrane of the vesicle was derived from the plasma membrane and the inner one possibly derived from the membrane of an intracellular vesicle. Immuno-gold labeling showed that VSV M was exclusively located in a double-layered region. The released membranes were divided into three parts: the VSV M vesicles with SeV F and HN glycoproteins, SeV particles, and vesicles associated with the cytosolic components. The last abundantly contained phosphorylated SeV matrix (M) protein, which is not released in a usual SeV infection. Furthermore the VSV M protein expressed without using a virus vector was efficiently released into the culture medium. These results suggest that the VSV M protein has a budding activity per se and that SeV proteins are passively involved in the release of VSV M.

Animals↗
PubMed1999

Knockout of the Sendai virus C gene eliminates the viral ability to prevent the interferon-alpha/beta-mediated responses.

Sendai virus (SeV) renders cells unresponsive to interferon (IFN)-alpha. To identify viral factors involved in this process, we examined whether recombinant SeVs, which could not express V protein, subsets of C proteins (C, C', Y1 and Y2) or any of four C proteins, retained the capability of impeding IFN-alpha-mediated responses. Among these viruses, only the 4C knockout virus completely lost the ability to suppress the induction of IFN-alpha-stimulated gene products and the subsequent establishment of an anti-viral state. These findings reveal crucial roles of the SeV C proteins in blocking IFN-alpha-mediated responses.

Antiviral Agents↗
PubMed1999

Enhanced anti-HIV-1 activity of CC-chemokine LD78beta, a non-allelic variant of MIP-1alpha/LD78alpha.

We compared the anti-HIV-1 activity of CC-chemokine LD78beta with that of MIP-1alpha, another CC-chemokine which shows 94% sequence homology with LD78beta. Despite its close similarity to MIP-1alpha, the anti-HIV-1 activity of LD78beta appeared to be nearly 10 times higher than that of MIP-1alpha. Mutagenesis of MIP-1alpha showed that the N-terminal additional tetrapeptide, which was present in LD78beta and absent in MIP-1alpha, is responsible for enhanced anti-HIV-1 activity. The N-terminal structure-function relationship of LD78beta described here will be of value in understanding the chemokine-receptor interactions and designing anti-HIV-1 compounds based on LD78beta.

Animals↗
PubMed1999

Sendai virus-based production of HIV type 1 subtype B and subtype E envelope glycoprotein 120 antigens and their use for highly sensitive detection of subtype-specific serum antibodies.

We previously described a Sendai virus (SeV)-based expression system for the recombinant gp120 of HIV-1 subtype B (rgp120-B), which has permitted the production of antigenetically and functionally authentic gp120 at a concentration as high as 6 microg/ml of culture supernatant (Yu D et al.: Genes Cells 1997;2:457-466). Here the same procedure was successfully applied to the production of HIV-1 subtype E gp120 (rgp120-E). The remarkable production of the proteins by the SeV expression system enabled us to use crude culture supernatants for serological and functional studies of gp120s. The immunological authenticity of rgp120-E was verified by patient sera and anti-V3 loop monoclonal antibodies specific for HIV-1 subtypes B and E. CD4-binding properties were corroborated by FACS analyses. The rgp120s were then used in an enzyme immunoassay (rgp120-EIA) to detect antibodies in the sera of HIV-1-infected individuals, and the performance was assessed in comparison with a conventional V3 loop peptide EIA (V3-EIA). The initial evaluation of a serum panel (n = 164) consisting of 76 subtype E and 88 subtype B sera revealed that the rgp120-EIA was nearly 1000-fold more sensitive than the V3-EIA and was able to detect subtype-specific antibody with 100% sensitivity and with a complete correlation with the genotypes, whereas the V3-EIA failed to detect 9 and 24% of the same subtype E and B sera, respectively. Furthermore, a study employing a panel of 28 international sera with known genotypes (HIV-1 subtypes A through F) confirmed the remarkable specificity of this method. An EIA reactivity higher than 1.0 was an unambiguous predictor of HIV-1 subtype E and B infections. The data imply the presence of strong subtype-specific epitopes for antibody bindings to these rgp120s.

Antibodies, Viral↗
PubMed1999

Accommodation of foreign genes into the Sendai virus genome: sizes of inserted genes and viral replication.

Sendai virus (SeV) is an enveloped virus with a negative sense genome RNA of about 15.3 kb. We previously established a system to recover an infectious virus entirely from SeV cDNA and illustrated the feasibility of using SeV as a novel expression vector. Here, we have attempted to insert a series of foreign genes into SeV of different lengths to learn how far SeV can accommodate extra genes and how the length of inserted genes affects viral replication in cells cultured in vitro and in the natural host, mice. We show that a gene up to 3.2 kb can be inserted and efficiently expressed and that the replication speed as well as the final virus titers in cell culture are proportionally reduced as the inserted gene length increases. In vivo, such a size-dependent effect was not very clear but a remarkably attenuated replication and pathogenicity were generally seen. Our data further confirmed reinforcement of foreign gene expression in vitro from the V(-) version of SeV in which the accessory V gene had been knocked out. Based on these results, we discuss the utility of SeV vector in terms of both efficiency and safety.

Animals↗
PubMed1999

The genome nucleotide sequence of a contemporary wild strain of measles virus and its comparison with the classical Edmonston strain genome.

The only complete genome nucleotide sequences of measles virus (MeV) reported to date have been for the Edmonston (Ed) strain and derivatives, which were isolated decades ago, passaged extensively under laboratory conditions, and appeared to be nonpathogenic. Partial sequencing of many other strains has identified >/=15 genotypes. Most recent isolates, including those typically pathogenic, belong to genotypes distinct from the Edmonston type. Therefore, the sequence of Ed and related strains may not be representative of those of pathological measles circulating at that or any time in human populations. Taking into account these issues as well as the fact that so many studies have been based upon Ed-related strains, we have sequenced the entire genome of a recently isolated pathogenic strain, 9301B. Between this recent isolate and the classical Ed strain, there were 465 nucleotide differences (2.93%) and 114 amino acid differences (2.19%). Computation of nonsynonymous and synonymous substitutions in open reading frames as well as direct comparisons of noncoding regions of each gene and extracistronic regulatory regions clearly revealed the regions where changes have been permissible and nonpermissible. Notably, considerable nonsynonymous substitutions appeared to be permissible for the P frame to maintain a high degree of sequence conservation for the overlapping C frame. However, the cause and the effect were largely unclear for any substitution, indicating that there is a considerable gap between the two strains that cannot be filled. The sequence reported here would be useful as a reference of contemporary wild-type MeV.

3' Untranslated Regions↗