Biomedical subjects

N Uchida

Publications and source records attributed to N Uchida.

At least 55 records · Page 3Linked to original sources

PubMed2000

Improved in vivo antitumor efficacy and reduced systemic toxicity of carboxymethylpullulan-peptide-doxorubicin conjugates.

The antitumor efficacy of the conjugate of doxorubicin (DXR) and carboxymethylpullulan (CMPul) with Phe-Gly spacer (CMPul-FG-DXR) was evaluated using murine tumor models and compared with that of DXR. The conjugate exhibited higher antitumor efficacy against Lewis lung carcinoma than DXR. Complete tumor regression followed by long-term tumor-free survival was frequently observed when CMPul-FG-DXR was administered i.v. three times at a dose equivalent to 10 mg / kg of DXR. The superior survival as well as anti-metastatic effect of CMPul-FG-DXR in comparison with DXR was also demonstrated with the M5076 murine reticulosarcoma model. Body weight loss in mice treated with the conjugate was less than that in the DXR-treated group, indicating lower systemic toxicity of CMPul-FG-DXR. Simply mixing CMPul with DXR did not enhance the antitumor activity of DXR, showing that the conjugation of DXR with CMPul is necessary for improved antitumor activity. However, no enhanced antitumor efficacy of the conjugates was observed against a non-solid tumor model such as P388 leukemia. In summary, improved antitumor efficacy with reduced systemic toxicity of CMPul-FG-DXR was demonstrated in the present study. CMPul-FG-DXR may be useful as a cancer chemotherapy agent against solid tumors and metastases.

Animals↗

PubMed2000

Phenotypes of fission yeast defective in ubiquinone production due to disruption of the gene for p-hydroxybenzoate polyprenyl diphosphate transferase.

Ubiquinone is an essential component of the electron transfer system in both prokaryotes and eukaryotes and is synthesized from chorismate and polyprenyl diphosphate by eight steps. p-Hydroxybenzoate (PHB) polyprenyl diphosphate transferase catalyzes the condensation of PHB and polyprenyl diphosphate in ubiquinone biosynthesis. We isolated the gene (designated ppt1) encoding PHB polyprenyl diphosphate transferase from Schizosaccharomyces pombe and constructed a strain with a disrupted ppt1 gene. This strain could not grow on minimal medium supplemented with glucose. Expression of COQ2 from Saccharomyces cerevisiae in the defective S. pombe strain restored growth and enabled the cells to produce ubiquinone-10, indicating that COQ2 and ppt1 are functional homologs. The ppt1-deficient strain required supplementation with antioxidants, such as cysteine, glutathione, and alpha-tocopherol, to grow on minimal medium. This suggests that ubiquinone can act as an antioxidant, a premise supported by our observation that the ppt1-deficient strain is sensitive to H(2)O(2) and Cu(2+). Interestingly, we also found that the ppt1-deficient strain produced a significant amount of H(2)S, which suggests that oxidation of sulfide by ubiquinone may be an important pathway for sulfur metabolism in S. pombe. Ppt1-green fluorescent protein fusion proteins localized to the mitochondria, indicating that ubiquinone biosynthesis occurs in the mitochondria in S. pombe. Thus, analysis of the phenotypes of S. pombe strains deficient in ubiquinone production clearly demonstrates that ubiquinone has multiple functions in the cell apart from being an integral component of the electron transfer system.

Alkyl and Aryl Transferases↗

PubMed2000

[Clinical and experimental observation of glistening in acrylic intraocular lenses].

PURPOSE: To study whether the glistening on implanted acrylic intracular lenses increases or not. METHOD: 1. Prospective study: We studied the glistening on 49 implanted acrylic intraocular lenses, particularly the time of appearance and increase after glistening appeared. 2. EXPERIMENT: We kept an intraocular lens immersed in saline solution at 50 degrees centigrade for two hours and then moved this lens into saline solution at 35 degrees centigrade, and observed this lens during immersion. RESULTS: 1. Prospective study: Glistening was present in 28 eyes (57%), and appeared from 2 to 16 months postoperatively. A few months after appearance it become stable and did not increase further. 2. EXPERIMENT: On the 10th day after observation, we could see glistening on the lenses. The points of glistening were 10 microns or less in size, and did not change during 60 days of observation. CONCLUSION: The glistening in acrylic intraocular lenses seemed to become stable a few months after appearance. This our experimental method is useful, because it gives us glistening similar to clinical cases in a short time.

Acrylates↗

PubMed2000

Down-regulation of human telomeric protein TRF1 gene expression during myeloid differentiation in human hematopoietic cells.

The maintenance of telomere length is crucial for cell survival. Recently, it has been indicated that the human telomeric protein TRF1 is involved in the negative feedback mechanism that stabilizes telomere length. We studied TRF1 mRNA expression in hematopoietic cells to clarify the relation between TRF1 and telomerase by semiquantitative reverse transcriptase-polymerase chain reaction. In polymorphonuclear cells and monocytes isolated from peripheral blood, relatively low levels of TRF1 mRNA expression were seen, compared with those of lymphocytes and CD34+. We then assessed TRF1 mRNA expression in CD34+ cells cultured in vitro with growth factors. After 4 weeks of culture, all the cells showed myeloid differentiation, and telomerase activity was down-regulated. TRF1 mRNA was expressed in CD34+ cells but was down-regulated in cells cultured for 4 weeks. We conclude that TRF1 mRNA expression is down-regulated in accordance with telomerase down-regulation during the course of myeloid differentiation.

Antigens, CD34↗

PubMed1999

The eukaryotic polypeptide chain releasing factor (eRF3/GSPT) carrying the translation termination signal to the 3'-Poly(A) tail of mRNA. Direct association of erf3/GSPT with polyadenylate-binding protein.

The mammalian GTP-binding protein GSPT, whose carboxyl-terminal sequence is homologous to the eukaryotic elongation factor EF1alpha, binds to the polypeptide chain releasing factor eRF1 to function as eRF3 in the translation termination. The amino-terminal domain of GSPT was, however, not required for the binding. Search for other GSPT-binding proteins in yeast two-hybrid screening system resulted in the identification of a cDNA encoding polyadenylate-binding protein (PABP), whose amino terminus is associating with the poly(A) tail of mRNAs presumably for their stabilization. The interaction appeared to be mediated through the carboxyl-terminal domain of PABP and the amino-terminal region of GSPT. Interestingly, multimerization of PABP with poly(A), which is ascribed to the action of its carboxyl-terminal domain, was completely inhibited by the interaction with the amino-terminal domain of GSPT. These results indicate that GSPT/eRF3 may play important roles not only in the termination of protein synthesis but also in the regulation of mRNA stability. Thus, the present study is the first report showing that GSPT/eRF3 carries the translation termination signal to 3'-poly(A) tail ubiquitously present in eukaryotic mRNAs.

Eukaryotic Cells↗

PubMed1999

Interferon-gamma prevents apoptosis in Epstein-Barr virus-infected natural killer cell leukemia in an autocrine fashion.

The significant function of cytokines includes maintenance of cell survival as well as induction of cell differentiation and/or proliferation. We demonstrate here that interferon-gamma (IFN-gamma) plays a role for progression of Epstein-Barr virus (EBV)-infected natural killer cell leukemia (NK leukemia) through maintaining cell survival. NK leukemia cells obtained from 7 patients had clonal episomal forms of EBV, indicating that the leukemic cells were of clonal origin. Although normal NK cells constitutively expressed Bcl-2, the EBV-infected NK leukemia cells lacked endogenous Bcl-2 expression and were hypersensitive to apoptosis in vitro. The addition of IFN-gamma to the culture significantly inhibited their spontaneous apoptosis without inducing cell proliferation or upregulation of Bcl-2. The NK leukemia cells constitutively secreted IFN-gamma, and the patients' sera contained a high concentration of IFN-gamma, levels that were high enough to prevent NK leukemia cells from apoptosis. Bcl-XL was not involved in the IFN-gamma-induced NK leukemia cell survival. These data suggest that the acquisition of IFN-gamma-mediated autocrine survival signals, other than Bcl-2 or BCL-XL, might be important for the development of EBV-infected NK leukemia.

Adolescent↗

PubMed1999

Correlation of antiangiogenic and antitumor efficacy of N-biphenyl sulfonyl-phenylalanine hydroxiamic acid (BPHA), an orally-active, selective matrix metalloproteinase inhibitor.

The antiangiogenic activity and antitumor efficacy of a newly developed matrix metalloproteinase (MMP) inhibitor were examined. N-biphenyl sulfonyl-phenylalanine hydroxiamic acid (BPHA) potently inhibits MMP-2, -9, and -14, but not MMP-1, -3, or -7. In contrast, (-)BPHA, an enantiomer of BPHA, was inactive against all MMPs tested. Daily oral administration of 200 mg/kg BPHA, but not (-)BPHA in mice resulted in potent inhibition of tumor-induced angiogenesis, primary tumor growth, and liver metastasis. The growth inhibition activity of BPHA was 48% and 45% in a B16-BL6 melanoma and F2 hemangio-endothelioma model, respectively. BPHA also showed 42% inhibition of the liver metastasis of C-1H human colon carcinoma cells. These results indicate that selective MMP inhibition is correlated with antiangiogenic and antitumor efficacy and that the selective MMP inhibitor BPHA has therapeutic potential.

Animals↗

PubMed1999

HCA, an immunoglobulin-like adhesion molecule present on the earliest human hematopoietic precursor cells, is also expressed by stromal cells in blood-forming tissues.

We have previously shown that the HCA/ALCAM (CD166) glycoprotein, a member of the immunoglobulin family that mediates both homophilic and heterophilic cell-cell adhesion, via the CD6 ligand, is expressed at the surface of all of the most primitive CD38(-/lo), Thy-1(+), rho123(lo), CD34(+) hematopoietic cells in human fetal liver and fetal and adult bone marrow. In the present report we show that HCA is also expressed by subsets of stromal cells in the primary hematopoietic sites that sequentially develop in the human embryo and fetus, ie, the paraaortic mesoderm, liver, thymus, and bone marrow. Adult bone marrow stromal cells established in vitro, including those derived from Stro-1(+) progenitors and cells from immortalized cell lines, express HCA. In contrast, no HCA expression could be detected in peripheral lymphoid tissues, fetal spleen, and lymph nodes. HCA membrane molecules purified from marrow stromal cells interact with intact marrow stromal cells, CD34(+) CD38(-) hematopoietic precursors, and CD3(+) CD6(+) peripheral blood lymphocytes. Finally, low but significant levels of CD6 are here for the first time detected at the surface of CD34(+) rho123(med/lo) progenitors in the bone marrow and in mobilized blood from healthy individuals. Altogether, these results indicate that the HCA/ALCAM surface molecule is involved in homophilic or heterophilic (with CD6) adhesive interactions between early hematopoietic progenitors and associated stromal cells in primary blood-forming organs.

Adult↗

PubMed1999

Atherosclerotic superficial temporal artery aneurysm: report of a case.

We herein report a rare case of an atherosclerotic superficial temporal artery (STA) aneurysm. The patient was a 34-year-old Japanese man. He noticed a throbbing swelling just in front of his right ear, which had slowly increased in size. There was no history of trauma. Digital subtraction angiography and ultrasound revealed an aneurysm measuring 2cm in diameter fed by STA. A ligation and resection were performed under local anesthesia. The recovery period was uneventful. A microscopic examination revealed a moderate degree of atherosclerosis. We found 48 cases of STA aneurysm in the Japanese literature from 1969 to 1997, including our case. Thirty-six of these cases (75.0%) were considered to be traumatic in origin. Three cases (6.2%) occurred after a craniotomy. To date, only nine reported cases (18.8%) have been attributed to a spontaneous or congenital etiology.

Adult↗

PubMed1999

Thermal distribution of radio-frequency inductive hyperthermia using an inductive aperture-type applicator: evaluation of the effect of tumour size and depth.

A new radio-frequency (RF) inductive hyperthermia device using an inductive aperture-type applicator (IATA) is proposed. This paper reports the evaluation of the heating characteristics of the IATA using a computer simulation and clinical thermal parameters obtained during treatment of superficial and subsurface-seated tumours. The configuration of the IATA is a one-turn square column-like coil whose bottom plate is set to face the heating target. The IATA has advantages over RF capacitive-type heating, such as: generating less heat in the subcutaneous fat layer; less convergency of electric line of force at the edge of the applicator; and no physical contact with the target lesion. The induced magnetic fields and electrical currents within the heating substance are simulated using computer-assisted design software for electro-magnetic analysis. A total of 40 superficial and subsurface tumours are treated with the IATA. Invasive thermometry is performed continuously for 110 sessions using multi-sensor probes of an optical thermometer. Thermal parameters (Tmax, Tmin, Tave) are assessed based on the tumour size and depth. The treated tumours are categorised into three groups according to tumour depth: group 1 (< 3 cm, n = 28), group 2 (3-5 cm, n = 35) and group 3 (> 5 cm, n = 47). The computer simulation shows that induced electrical currents run without convergency, parallel to the surface of the heating material. All thermal parameters of group 3 are significantly higher than those of group 1 and 2 (p < 0.05), indicating that the larger lesions tend to abtain a higher temperature distribution. In conclusion, RF inductive hyperthermia using the IATA results in effective temperature distributions in superficial and subsurface tumours, with large tumours being most effectively heated.

Aged↗

PubMed1999

Correlation of telomerase activity with development and progression of adult T-cell leukemia.

Telomerase is an enzyme that adds hexameric TTAGGG nucleotide repeats to the ends of vertebrate chromosomal DNAs (i.e. telomeres) to compensate for losses that occur with each round of DNA replication. Telomerase activity, demonstrable in most human tumors, enables them to maintain telomere stability. Peripheral blood mononuclear cells were sampled from 57 patients seropositive for human T-lymphotropic virus type I (HTLV-I), including 24 asymptomatic viral carriers, ten smoldering type, five chronic type, and 18 acute type adult T-cell leukemia (ATL). Telomerase activity was determined in samples using a modified telomeric repeat amplification protocol. We semiquantitatively determined telomerase activity by serial dilution of each sample. All of 23 samples from acute and chronic type ATL patients were positive, seven of ten (70%) smoldering type patients and seven of 24 (29.2%) asymptomatic viral carriers were positive. Disease progression from asymptomatic viral carrier to acute type correlated with telomerase activity. Two samples from chronic type ATL patients with relatively high telomerase activity progressed to the acute type within 1 month. Serum lactate dehydrogenase level also correlated with telomerase activity. These results indicate that reactivation of telomerase activity is a key event in development and progression of ATL, and telomerase could be a useful marker for predicting the course of disease. Accordingly, ATL could be a good candidate disease for trials of telomerase inhibitors, as novel anticancer drugs.

Adult↗

PubMed1999

Differential gene expression of human telomerase-associated protein hTERT and TEP1 in human hematopoietic cells.

The maintenance of telomere length is crucial for the survival of cells. Recently, genes for proteins that consist of human telomerase have been cloned and the results have indicated a close relationship between telomerase activity and its gene expression. We studied the mRNA expression of the telomerase-associated genes, hTERT and TEP1, in hematopoietic cells in order to clarify the relation between them and telomerase activity using semiquantitative RT-PCR. In polymorphonuclear cells and monocytes isolated from peripheral blood, which had no detectable telomerase activity, no hTERT mRNA expression was seen. On the other hand, lymphocytes and CD34-positive cells both demonstrated hTERT mRNA expression. TEP1 mRNA was detected in all samples, showing no differential expression. We then assessed hTERT and TEP1 mRNA expression in CD34-positive cells cultured in vitro with growth factors. After 4 weeks of culture, all the cells showed myeloid differentiation and the telomerase activity was downregulated. hTERT mRNA was expressed in CD34-positive cells, but was downregulated in 4-week-cultured cells. TEP1 showed no apparent differential expression. We conclude that hTERT mRNA expression is downregulated in accordance with telomerase downregulation during the course of myeloid differentiation, which suggests that it plays a crucial role in the expression of enzyme activity, while TEP1 has a much smaller role to play, if any.

Carrier Proteins↗

PubMed1999

Sweet's syndrome associated with chronic myelogenous leukemia: demonstration of leukemic cells within a skin lesion.

We report a case of acute febrile neutrophilic dermatosis, Sweet's syndrome, associated with chronic myelogenous leukemia (CML) in which we found rearrangement of the bcr gene in DNA obtained from a skin lesion as well as in blood DNA by Southern blot analysis. This indicated the presence of CML cells within the skin lesion. To our knowledge, this is the first report in which the presence of CML cells is shown within skin lesions of Sweet's syndrome. In our patient, leukocyte alkaline phosphatase activities returned to normal levels when he was suffering from Sweet's syndrome and decreased again to below normal levels after it subsided. Whether the normalization of leukocyte alkaline phosphatase activity is common among CML patients with Sweet's syndrome remains to be determined.

Blotting, Southern↗

PubMed1999

CD109 is expressed on a subpopulation of CD34+ cells enriched in hematopoietic stem and progenitor cells.

CD109 is a monomeric cell surface glycoprotein of 170 kD that is expressed on endothelial cells, activated but not resting T-lymphocytes, activated but not resting platelets, leukemic megakaryoblasts, and a subpopulation of bone marrow CD34+ cells. Observing an apparent association between CD109 expression and the megakaryocyte lineage (MK), we sought to determine whether CD109 was expressed on MK progenitors. In fetal bone marrow (FBM), a rich source of MK progenitors, CD109 is expressed on a mean of 11% of CD34- cells. Fluorescence activated cell sorting (FACS) of FBM CD34+ cells into CD109+ and CD109- fractions revealed that the CD34+CD109+ subset contained virtually all assayable MK progenitors, including the colony-forming unit-MK (CFU-MK) and the more primitive burst-forming unit-MK (BFU-MK). The CD34+CD109+ subset also contained all the assayable burst-forming units-erythroid (BFU-E), 90% of the colony-forming units-granulocyte/macrophage (CFU-GM), and all of the more primitive mixed lineage colony-forming units (CFU-mix). In contrast, phenotypic analysis of the CD34+CD109- cells in FBM, adult bone marrow (ABM) and cytokine-mobilized peripheral blood (MPB) demonstrated that this subset comprises lymphoid-committed progenitors, predominantly of the B-cell lineage. CD109 was expressed on the brightest CD34 cells identifiable not only in FBM, but also in ABM and MPB indicating that the most primitive, candidate hematopoietic stem cells (HSC) might also be contained in the CD109+ subset. In long-term marrow cultures of FBM CD34+ cells, all assayable cobblestone area forming cell (CAFC) activity was contained within the CD109+ cell subset. Further phenotypic analysis of the CD34+CD109+ fraction in ABM indicated that this subset included candidate HSCs that stain poorly with CD38, but express Thy-1 (CD90) and AC133 antigens, and efflux the mitochondrial dye Rhodamine 123 (Rho123). When selected CD34+ cells were sorted for CD109 expression and Rho123 staining, virtually all CAFC activity was found in the CD109+ fraction that stained most poorly with Rho123. CD34+ cells were also sorted into Thy-1 CD109+ and Thy-1 CD109+ fractions and virtually all the CAFC activity was found in the Thy-1+CD109+ subset. In contrast, the Thy-1-CD109+ fraction contained most of the short-term colony-forming cell (CFC) activity. CD109, therefore, is an antigen expressed on a subset of CD34+ cells that includes pluripotent HSCs as well as all classes of MK and myelo-erythroid progenitors. In combination with Thy-1, CD109 can be used to identify and separate myelo-erythroid and all classes of MK progenitors from candidate HSCs.

Adult↗

PubMed1999

Effect of peroxisome proliferator on extracellular glutathione peroxidase in rat.

Glutathione peroxidase (GPX) activity measured using tert-butyl hydroperoxide as a substrate detects solely cellular/classical GPX (cGPX) in rat liver and kidney, and extracellular/plasma glutathione peroxidase (EC-GPX) in rat serum. To investigate the effect of peroxisome proliferator on EC-GPX, we measured activities of GPX and catalase in rat liver, kidney and serum, and then we performed immunoblot and Northern blot analyses in the kidney. Rats were fed on a diet containing either 2% (w/w) di-2-ethylhexyl phthalate (DEHP) or 0.25% (w/w) clofibrate for two or three weeks, respectively. Catalase activity was increased 1.4-fold (p < 0.001) in the treated liver, but not in the kidney. GPX activity was decreased to 59.2% (DEHP) and 70.4% (clofibrate) of the control (p < 0.001) in the serum but was unaltered in the liver and kidney. The immunoreactivity for EC-GPX was also significantly decreased in the DEHP-treated kidney compared with the control. The mRNA levels of EC-GPX and cGPX were unaltered. The immunostaining for 4-hydroxy-2-nonenal, a maker of lipid peroxide, was more intense in the treated kidney compared with the control. These results suggest that EC-GPX is post-transcriptionally decreased by peroxisome proliferator through the oxidative stress in the renal tubules. This may be a new deleterious effect of an endocrine disruptor DEHP.

Aldehydes↗

PubMed1999

Elastic effects in disordered nematic networks.

Elastic effects in a model of disordered nematic elastomers are numerically investigated in two dimensions. Networks crosslinked in the isotropic phase exhibit an unusual soft mechanical response against stretching. It arises from a gradual alignment of orientationally correlated regions that are elongated along the director. A sharp crossover to a macroscopically aligned state is obtained on further stretching. The effect of random internal stress is also discussed.

Journal Article↗

PubMed1999

Combination chemotherapy with nedaplatin and cyclophosphamide in human ovarian cancer model.

The antitumor efficacy of the combination of nedaplatin (NDP) with cyclophosphamide (CPM) was evaluated using human ovarian cancer models. Since NDP has been found to have greater antitumor activity and lower nephrotoxicity than cisplatin (CDDP), we also compared the antitumor activity of NDP plus CPM with that of CDDP plus CPM. Increasing doses of NDP (16.5, 33 and 66 mg/kg as a total dose) and a fixed amount of CPM (174 or 348 mg/kg as a total dose) were injected three times at intervals of 7 days via the tail vein into mice implanted with RMUG-S, OC9-JCK or KF-28 human ovarian cancer. Simultaneous administration of NDP with CPM resulted in markedly enhanced inhibition of tumor growth for all cancers tested. The growth inhibition and survival effect of the combination therapy of NDP with CPM against KF-28 and OC9-JCK were as potent as those of CDDP plus CPM. Neither increased hematotoxicity nor a significant difference in maximum concentration, half time or area under the curve of platinum or CPM in plasma between the single and combined treatment was found. These results suggest that the combination of NDP with CPM may be clinically effective.

Animals↗

PubMed1999

Transduction of human progenitor hematopoietic stem cells by human immunodeficiency virus type 1-based vectors is cell cycle dependent.

Human immunodeficiency virus (HIV) type 1 vectors are highly efficient in their ability to transduce human progenitor hematopoietic stem cells (PHSC). Although mitosis was not required for transduction of these cells, transduction rates were much greater once cells had been cultured in the presence of cytokines. Transduction rates, however, rarely exceeded 70%. We demonstrate here that there is a distinct subpopulation that is more easily transduced by HIV vectors. These cells were distinguished by a disproportionate population in the S/G2/M phases of the cell cycle. By sorting them prior to transduction, we found that those cells in either the G1 or S/G2/M fraction were more readily transduced than G0 cells. Maintaining the cells in G0 by omitting cytokines from the medium reduced transduction rates by up to 10-fold. Addition of cytokines to the medium immediately after transduction did not improve the transduction efficiency as measured by expression of the transgene. Analysis of replication intermediates indicated that the block to transduction of G0 cells operated near the time of initiation of reverse transcription. These results suggest that although lentivirus vectors can transduce nondividing PHSC, transduction efficiency is severalfold greater once the cells exit G0 and enter G1. Further characterization of these more transducible cells and identification of the cellular factors responsible may enhance transduction while maintaining the pluripotentiality of the PHSC.

Cell Cycle↗