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M Nagano

Publications and source records attributed to M Nagano.

At least 55 records · Page 3Linked to original sources
PubMed2000

Activation of cerebral function by CS-932, a functionally selective M1 partial agonist: neurochemical characterization and pharmacological studies.

A newly synthesized agonist for muscarinic acetylcholine (ACh) receptors CS-932, (R)-3-(3-iso-xazoloxy)-1-azabicyclo-[2.2.2]octane hydrochloride, showed a relatively higher affinity for M1 than M2 receptors expressed in Chinese hamster ovary (CHO)-cells in comparison with ACh. CS-932 elevated the intracellular Ca2+ level only in M1-CHO cells, although ACh increased the level in both M1- and M3-CHO cells. CS-932 and ACh reduced forskolin-stimulated accumulation of cAMP in M2-CHO cells by 20% and 80%, respectively. This neurochemical profile of CS-932 indicates that the compound can activate M1-receptor-mediated functions selectively. CS-932 increased firing of cholinoceptive neurons in rat hippocampal slices, and this excitation was antagonized by pirenzepine, but not by AF-DX 116. CS-932 increased awake and decreased slow wave sleep episodes of daytime EEG in free-moving rats. It counteracted scopolamine-induced slow waves in rat cortical EEG. CS-932 also increased the power of alpha- and beta-waves, but decreased delta-wave of the cortical EEG in anesthetized monkeys. It ameliorated scopolamine-induced impairment of working memory in rats. Orally administered CS-932 had the best penetration into the brain among the muscarinic agonists tested and caused the least salivary secretion among the cholinomimetics examined. These results indicate that CS-932 has potential as a cognitive enhancer with fewer side effects in therapy for Alzheimer disease.

Animals↗
PubMed2000

Epstein-Barr virus (EBV)-induced B-cell proliferative disorder after chemotherapy in a patient with hemophagocytic lymphohistiocytosis with associated EBV-induced T-cell proliferation.

We report a case of Epstein-Barr virus (EBV)-associated lymphoproliferative disorder (LPD) which developed after chemotherapy for hemophagocytic lymphohistiocytosis (HLH), who had no history of immunodeficiency or familial X-linked LPD. In HLH, the presence of EBV in T-cells was confirmed by a combination of in situ hybridization (ISH) and immunostaining. Southern blot analysis using EBV-TR and immunoglobulin JH probes revealed oligoclonal proliferation of B-cells in each organ involved by abnormal B-lymphoid cells at autopsy. Combined ISH and immunostaining disclosed the presence of EBV in proliferating B-cells. Cytokine analysis during the period of T-cell activation in HLH revealed marked elevation of interferon (IFN) gamma, interleukin (IL)-10 and soluble IL-2 receptor (sIL-2R) and mild to moderate increases of tumor necrosis factor (TNF)-alpha were observed, while IFN gamma, IL-10 and sIL-2R were elevated initially during the HLH phase, which then decreased as LPD developed and B-cell proliferation predominated. Immunosuppressive chemotherapy for HLH may then have allowed latent EBV in B lymphocytes to induce transformation and oligoclonal proliferation of B-cells, finally resulting in LPD. Mechanisms of EBV-induced cell proliferation remain unclear, but alteration of various cytokines may be responsible for it.

Adult↗
PubMed2000

Measurement of human plasma phospholipid transfer protein by sandwich ELISA.

BACKGROUND: Plasma phospholipid transfer protein (PLTP) plays a central role in the remodeling of HDLs. Reliable and accurate methods for assaying PLTP concentration are required. METHODS: A sandwich ELISA for PLTP has been developed, using two monoclonal antibodies against recombinant human PLTP (rhPLTP) expressed in Chinese hamster ovary cells. The ELISA allows for the quantification of PLTP in the range 0.625-15.0 ng/assay (1.2-30.0 mg/L). Intra- and interassay CVs were <3.0% and <4.2% respectively. The assay was used to quantify plasma PLTP concentrations in 132 Japanese subjects (75 males and 57 females). RESULTS: PLTP concentrations were 12.0 +/- 3. 0 mg/L (mean +/- SD; range, 4.9-20.5 mg/L). No sex difference was observed. Plasma PLTP concentration was positively correlated with HDL-cholesterol (r = 0.72; P: <0.001), apolipoprotein (apo) A-I (r = 0.62; P: <0.001) and HDL(2)-cholesterol (r = 0.72; P: <0.001), and was negatively correlated with triacylglycerol (r = -0.45; P: <0. 001). There was no correlation with plasma apo A-II. These results agree with other evidence that plasma PLTP is associated with large apo A-I-containing lipoproteins. There was no correlation (r = -0. 01) between plasma PLTP and plasma phosphatidylcholine transfer activity (range, 3.5-10.5 micromol. mL(-1). h(-1)), suggesting that PLTP may exist in active and inactive forms. CONCLUSION: This new ELISA will be of value for further studies of PLTP in health and disease.

Adult↗
PubMed1999

Inhibition of transcription of class II, but not class III and I, genes in Xenopus postblastular embryos overexpressed with the TBP-binding protein, Dr1 (NC2beta).

Dr1 (NC2beta) is known to effectively repress transcription of class II genes, and much less effectively class III genes, but not class I genes through its binding to the TATA-binding protein (TBP), which is the major component of the basal transcription factor for polymerases II, III, and I. Previously, we isolated Xenopus Dr1 cDNA, and demonstrated that its mRNA is transcribed in oocytes and is inherited into early embryos, but its level decreases in later stages. Here, we overexpressed Xenopus Dr1 in Xenopus embryos and, found that the overexpression significantly reduces the levels of poly(A), cytoskeletal actin and histone H4 mRNAs, and the labeling of heterogeneous mRNA-like RNA in postblastular embryos, without affecting tRNA and rRNA syntheses. These results indicate that the overexpressed Dr1 specifically down-regulates the transcription of class II, but not class III and I, genes, and suggest that Dr1 plays an important role in the control of transcription in Xenopus embryogenesis.

Actins↗
PubMed1999

Clonal expansion of alphabeta-T lymphocytes with inverted Jbeta1 bias in familial hemophagocytic lymphohistiocytosis.

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare but fatal disease in infancy. There are no previous reports on the clonality of T cells in FHL patients. We analyzed here the clonality of alphabeta-T cells in 5 FHL patients using an inverse reverse transcriptase-polymerase chain reaction (RT-PCR) of the T-cell receptor variable region gene (TCR V), a joining region gene of the beta chain (Jbeta)-PCR, a single-strand conformation polymorphism (SSCP), and sequence analysis. A high frequency (15%) of Vbeta and Valpha families was observed in 3 of 5 and 4 of 4 patients examined, respectively. In 19 Vbeta repertoires, including all highly frequent Vbeta, the Jbeta-PCR analysis showed restricted usage of the Jbeta family, indicating a marked bias to Jbeta1 subsets (the mean rate of Jbeta1:Jbeta2 was 87:13 in 65% of the alphabeta-T cells) in widespread alphabeta-T cells (in all patients but 1). In all patients, the clonality of specific Vbeta-Jbeta fragment expanded was confirmed by SSCP and sequence analysis. These results suggest that the existence of clonal expansion and restricted Jbeta1 usage of T cells in FHL is genetically associated with the pathogenesis and the immunodysfunction of the disease. These results help to explain some of the abnormal functional behaviors of T cells in FHL and raise new questions regarding the mechanisms responsible for the restricted clonal diversity.

Amino Acid Sequence↗
PubMed1999

Clonal change of infiltrating T-cells in children with familial hemophagocytic lymphohistiocytosis: possible association with Epstein-Barr virus infection.

BACKGROUND: Although familial hemophagocytic lymphohistiocytosis (FHL) has been considered a T-cell disorder, to the authors' knowledge there are no previous reports on the clonal basis of FHL. In the current study the authors analyzed the clonality of T-cells in two FHL patients at the time of disease onset and at disease progression. METHODS: Patient 1 had FHL and died of recurrent disease 4 months after bone marrow transplantation (BMT). His liver and spleen showed massive infiltrations of CD3+, CD4-, and CD8+ T-cells. The Epstein-Barr virus (EBV) genome was detected by in situ hybridization. Patient 2 also had FHL and died of progressive disease 9 weeks after the onset of disease despite chemotherapy. A polymerase chain reaction (PCR) analysis showed positive EBV genome in the peripheral blood, liver, and spleen of Patient 2. In the two patients, T-cell receptor-beta and alpha-chain variable region (TCR Vbeta and V alpha) repertoires in peripheral mononuclear cells were analyzed at the time of disease onset and at disease progression by the inverse PCR method. When a high usage (> 15%) of a specific Vbeta family member was observed, a clonal analysis was performed by PCR using beta-chain joining region (Jbeta) primers. The clonality of specific Vbeta-Jbeta fragments was confirmed by a single strand confirmation polymorphism (SSCP) analysis. RESULTS: Although there was no preferential usage of Vbeta in Patient 1, the exclusive expression of Jbeta1.2 for Vbeta13 was observed. A high frequency of Vbeta13 also was observed at the time of disease progression, but the Jbeta fragment for Vbeta13 was polyclonal. In Patient 2, the restricted usage of Jbeta1.6 for Vbeta5a was observed at the time of disease onset, whereas Jbeta1.1 and 1.2 for Vbeta4 were observed exclusively at the time of disease progression. The clonality of Vbeta13-Jbeta1.2 in Patient 1 and Vbeta5a-Jbeta1.6 and Vbeta4-Jbeta1.1/Jbeta1.2 in Patient 2 was confirmed by SSCP analysis. CONCLUSIONS: These findings suggest that the polyclonal T-cell lymphoproliferative disease associated with EBV was induced after BMT in Patient 1, and that the clonal change of expanded T-cells also was induced by EBV in Patient 2. The clonal analysis of T-cells is a useful tool to clarify the pathogenesis of FHL.

Disease Progression↗
PubMed1999

Effect of TPA on aquaporin 4 mRNA expression in cultured rat astrocytes.

Aquaporin 4 (AQP4) is a predominant water channel protein in mammalian brains, localized in the astrocyte plasma membrane. The regulation of AQP4 is believed to be important for the homeostasis of water in the brain, but the AQP4 regulatory mechanisms are not yet known. In this study, we investigated the effect of a protein kinase C (PKC) activator on the expression of AQP4 mRNA in cultured rat astrocytes. Cultured rat astrocytes constitutively expressed AQP4 mRNA. Treatment of the cells with 0.1 microM of phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA), an activator of PKC, caused a rapid decrease in AQP4 mRNA. This effect was time- and dose-dependent. The TPA-induced decrease in AQP4 mRNA was inhibited by a relatively specific PKC inhibitor, 1-(5-isoquinoline sulfonyl)-2-methylpiperazine (H7) in a dose-dependent manner. Moreover, prolonged treatment of the cells with TPA eliminated the subsequent decrease in AQP4 mRNA by TPA. These results strongly suggest that the TPA-induced decrease in AQP4 mRNA is mediated by PKC activation. To test whether the effect of TPA requires protein synthesis, astrocytes were pretreated with cycloheximide, an inhibitor of protein synthesis. Pretreatment of the cells with cycloheximide did not inhibit the decrease in AQP4 mRNA induced by TPA. To test whether the TPA-induced decrease in AQP4 was due to a decrease in the mRNA stability, we examined the effect of actinomycin D, an inhibitor of transcription, on TPA-treated cells. The stability of AQP4 mRNA was not decreased by the pretreatment of the cells with actinomycin D. The results suggest that AQP4 mRNA is inhibited by TPA via PKC activation without de novo protein synthesis, and that the inhibition of AQP4 mRNA could be at the transcriptional level.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1999

Restricted diversification of T-cells in chronic active Epstein-Barr virus infection: potential inclination to T-lymphoproliferative disease.

To assess the abnormal T-cell expansion in chronic active Epstein-Barr virus infection (CAEBV), T-cell antigen receptor (TCR) repertoire was analyzed in four patients with the disease. All fulfilled the diagnostic criteria of CAEBV, presenting with fever, hepatosplenomegaly, cytopenia, abnormal high titers of anti EBV-antibodies, and positive EBV genome of unknown cause. Southern blotting probed with EBV-terminal repeats and TCR Cbeta gene indicated clonal expansion of the infected cells in 3 and 2 patients, respectively. The number of CD4+ HLA-DR+ cells appreciably increased in patients 1 (59%) and 2 (24%), who had a coronary aneurysm and central nervous system involvement, respectively. TCR gene expression examined by the inverse polymerase chain reaction methods revealed that Vbeta gene usages were preferential in all patients (Vbeta7 and Vbeta12: patient 1, Vbeta4: patient 2, Vbeta13: patients 3 and 4), compared with those in healthy controls. Valpha18 gene expression was remarkably high in patients 1 and 2. Moreover, Jbeta gene expression was skewing in the reigning Vbeta clones in all patients. Vbeta4-Jbeta1.5 and Vbeta13-Jbeta1.5 genes were clonally expressed in patients 2 and 4, respectively. These results suggest that CAEBV is associated with the restricted diversity of T-cells, which may stem from the sustained expansion of oligoclonal T-cells possibly driven by conventional viral antigens, but not, superantigens. Although the study is limited by the small number of patients, the unbalanced T-cell repertoire might contribute to the evolution of T-lymphoproliferative disease, otherwise, imply the innate defective immunity to EBV in CAEBV patients.

Adolescent↗
PubMed1999

Clonal dissemination of T-lymphocytes in scid mice from familial hemophagocytic lymphohistiocytosis.

BACKGROUND: Although familial hemophagocytic lymphohistiocytosis (FHL) has been considered a disorder of T-cell dysfunction, there is no evidence of the clonal origin of T-cells in this disease. PROCEDURE: We engrafted mononuclear cells (MNCs) from five FHL patients into scid mice and examined the infiltration of human cells in mouse organs. The characterization of human cells that infiltrated in the mouse organs was then performed. RESULTS: A diffuse infiltration of human lymphoid cells was detected in scid mice treated with 1 x 10(6) MNCs from one of the five patients. These cells were positive for HLA-DR and CD3, but negative for CD4, CD8, CD20, and CD68, suggesting the infiltration of double negative (DN) T-cells. The MNCs from the other four patients induced murine lymphoma-like disease; T-cell lymphoma in one and lymphoma of unknown origin in three. The characterization of these human DN T-cells was performed. The analysis of the Vbeta repertoire showed no preferential usage of the Vbeta family in MNCs, while the dominant expression of Vbeta13 was detected in T-cells infiltrating in the spleen and lung. A Jbeta analysis showed the restricted usage of Jbeta1.2 for Vbeta13 in these cells, and the clonality of Vbeta13-Jbeta1.2 fragment was confirmed by a single-strand confirmation polymorphism analysis. The analysis of the Valpha repertoire showed that Valpha24 was exclusively used in these DN T-cells, but no usage of JalphaQ for Valpha24 was observed. CONCLUSIONS: A clonal expansion of T-cells was induced in scid mice by the engraftment of MNCs from an FHL patient. The infiltration of DN alphabeta T-cells bearing invariant Valpha24 T-cell receptor in mouse organs may provide a useful clue to the pathogenesis of FHL. In the patients whose MNCs induced murine lymphoma-like disease, some cytokines or unknown factors that stimulate the growth and the tumorigenicity of murine lymphocytes might be produced by the MNCs engrafted in scid mice. Further study is needed to confirm the validity of our experimental approach and the findings observed in scid mice by using more FHL samples.

Animals↗
PubMed1999

Mutation analysis of iduronate-2-sulphatase gene in 24 patients with Hunter syndrome: characterisation of 6 novel mutations. Mutation in brief no. 249. Online.

Hunter syndrome is a rare, X-linked, recessively inherited disease affecting approximately 1 in 132,000 males. The disease is caused by the inability to degrade dermatan sulphate and heparan sulphate due to mutations in the iduronate-2-sulphatase gene (IDS). The mutations causing the disorder are heterogeneous, ranging from small micro-lesions to gross deletions and inversions. We have screened DNA samples from a panel of 24 unrelated Hunter syndrome patients and have identified mutations in 16 individuals. Six mutations represent novel changes in the gene and these include two single base deletions (1264DC and 1632/3DT); two single base insertions (776/8insC and 1082insT); and two missense mutations--Y264N (914T-->G) and Q465P (1518A-->C). An additional two missense mutations and one splice site alteration identified in this study have been described previously. Southern analysis revealed complete or partial gene deletions in a further 7 patients.

DNA Mutational Analysis↗
PubMed1999

Jumping translocation of homogeneously staining region and tetraploidy with double minutes in acute myelomonocytic leukemia.

We report a 71-year-old patient with acute myelomonocytic leukemia (AMMoL) who had complicated chromosomal abnormalities showing diploidy with a jumping translocation of a homogeneously staining region (hsr) and tetraploidy with double minutes (dmin). The analysis of gene amplification showed that hsr and dmin were the results of C-ETS 1 gene amplification. After induction chemotherapy, tetraploidy with dmin completely disappeared, while diploidy with hsr and del(11)(q23) remained until the patient died. It is speculated that hsr is more stable than dmin during chemotherapy and that the presence of tetraploidy is not necessarily a factor of poor response to chemotherapy for acute leukemia.

Aged↗
PubMed1999

Pattern and kinetics of mouse donor spermatogonial stem cell colonization in recipient testes.

Recently a system was developed in which transplanted donor spermatogonial stem cells establish complete spermatogenesis in the testes of an infertile recipient. To obtain insight into stem cell activity and the behavior of donor germ cells, the pattern and kinetics of mouse spermatogonial colonization in recipient seminiferous tubules were analyzed during the 4 mo following transplantation. The colonization process can be divided into three continuous phases. First, during the initial week, transplanted cells were randomly distributed throughout the tubules, and a small number reached the basement membrane. Second, from 1 wk to 1 mo, donor cells on the basement membrane divided and formed a monolayer network. Third, beginning at about 1 mo and continuing throughout the observation period, cells in the center of the network differentiated extensively and established a colony of spermatogenesis, which expanded laterally by repeating phase two and then three. An average of 19 donor cell-derived colonies developed from 10(6) cells transplanted to the seminiferous tubules of a recipient testis; the number of colonized sites did not change between 1 and 4 mo. However, the length of the colonies increased from 0.73 to 5.78 mm between 1 and 4 mo. These experiments establish the feasibility of studying in a systematic and quantitative manner the pattern and kinetics of the colonization process. Using spermatogonial transplantation as a functional assay, it should be possible to assess the effects of various treatments on stem cells and on recipient seminiferous tubules to provide unique insight into the process of spermatogenesis.

Animals↗
PubMed1999

Carcinoembryonic antigen and carbohydrate antigen 19-9-producing adenocarcinoma of the prostate: report of an autopsy case.

Prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) are well known as specific tumor markers of prostate cancer, but carcinoembryonic antigen (CEA)- and carbohydrate antigen 19-9 (CA19-9)-producing adenocarcinoma originating in the prostate is rare. We report here a case of prostatic adenocarcinoma positive for these 4 tumor markers in a 50-year-old man who had initially complained about chest pain due to metastatic bone tumor. In spite of the extensive treatment involving hormone and radiation therapy, the patient died of rapid tumor extension only 4 months after initial diagnosis. Autopsy revealed multiple metastases to the bone, liver, lungs and lymph nodes. Histologically, two types of adenocarcinoma were involved in both primary prostate and metastatic sites: one was a poorly differentiated adenocarcinoma positive for PSA and PAP but not CEA or CA19-9, and the other one was a less differentiated adenocarcinoma partially positive for CEA and CA19-9 but not for PSA or PAP. Based on this case and previous cases by review of the literature, CEA- and CA19-9-producing adenocarcinoma of the prostate was suggested to rapidly progress with multiple metastases and to show poor prognosis with strong resistance to any treatment.

Acid Phosphatase↗
PubMed1999

RBE-LET relationships of high-LET radiations in Drosophila mutations.

The relative biological effectiveness (RBE) of 252Cf neutrons and synchrotron-generated high-energy charged particles for mutation induction was evaluated as a function of linear energy transfer (LET), using the loss of heterozygosity for wing-hair mutations and the reversion of the mutant white-ivory eye-color in Drosophila melanogaster. Loss of heterozygosity for wing-hair mutations results predominantly from mitotic crossing over induced in wing anlage cells of larvae, while the reverse mutation of eye-color is due to an intragenic structural change (2.96 kb-DNA excision) in the white locus on the X-chromosome. The measurements were performed in a combined mutation assay system so that induced mutant wing-hair clones as well as revertant eye-color clone can be detected simultaneously in the same individual. Larvae were irradiated at the age of 3 days post oviposition with 252Cf neutrons, carbon beam or neon beam. For the neutron irradiation, the RBE values for wing-hair mutations were larger than that for eye-color mutation by about 7 fold. The RBE of carbon ions for producing the wing-hair mutations increased with increase in LET. The estimated RBE values were found to be in the range 2 to 6.5 for the wing-hair. For neon beam irradiation, the RBE values for wing-hair mutations peak near 150 keV/micron and decrease with further increase in LET. On the other hand, the RBE values for the induction of the eye-color mutation are nearly unity in 252Cf neutrons and both ions throughout the LET range irradiated. We discuss the relationships between the initial DNA damage and LET in considering the mechanism of somatic mutation induction.

Animals↗
PubMed1999

In vitro fertilization and cortical granule distribution of bovine oocytes having heterogeneous ooplasm with dark clusters.

In vitro maturation, fertilization and subsequent development of oocytes with homogeneous (category 1), or heterogeneous ooplasm (category 2) were investigated. No significant differences were observed in the nuclear maturation and total fertilization rates between the two categories. However, category 2 oocytes showed a higher normal fertilization rate due to their lower incidence of polyspermy as compared to category 1 oocytes. Electron microscopic study revealed that all category 2 oocytes had cortical granules lined up next to the plasma membrane, and that some category 1 oocytes still had small clusters of cortical granules after maturation. Although the proportion of cleaved zygotes was higher in category 2, the percentages of cleaved zygotes that developed to the blastocyst stage did not differ between the two categories. These results demonstrate that oocytes with heterogeneous ooplasm have a higher capacity for normal fertilization due to the reduction in polyspermy. This can be attributed to the normal distribution of cortical granules in category 2 oocytes after maturation.

Animals↗
PubMed1999

Evidence for the role of oxidative stress in acute ischemic heart disease: a brief review.

BACKGROUND: Although contractile performance of the acutely damaged ischemic heart is invariably depressed on reperfusion (myocardial stunning), the mechanisms of cardiac dysfunction in stunned myocardium are poorly understood. OBJECTIVES: To review briefly the current state of knowledge and to provide further experimental evidence of whether oxidative stress plays a crucial role in cardiac dysfunction and membrane abnormalities due to ischemia-reperfusion. MATERIALS AND METHODS: Isolated rat hearts perfused in the absence or presence of superoxide dismutase (SOD) plus catalase, a well known oxyradical scavenger system, were subjected to 30 mins of global ischemia and 60 mins of reperfusion. Cardiac performance, hydrogen peroxide and calcium contents, lipid peroxidation and membrane activities associated with calcium transport were measured in the control, ischemic and ischemic- reperfused hearts. RESULTS: Cardiac dysfunction, as reflected by depressed left ventricular developed pressure, +dP/dt and -dP/dt as well as elevated left ventricular end-diastolic pressure, in the ischemic-reperfused heart was associated with increased hydrogen peroxide, calcium and malondialdehyde contents as well as increased formation of conjugated dienes. These changes due to ischemia-reperfusion were attenuated in hearts treated with SOD plus catalase. Both ischemia and ischemic-reperfused hearts showed depressions in sarcolemmal Na+/K+-ATPase and sodium-calcium exchange, as well as sarcoplasmic reticular calcium uptake and calcium release activities; these membrane abnormalities were also partially prevented by the presence of SOD plus catalase. CONCLUSIONS: Oxidative stress due to the formation of hydrogen peroxide leading to lipid peroxidation and sulfhydryl group oxidation during ischemia-reperfusion seems to be one of the mechanisms that may produce membrane defects and result in intracellular calcium overload and cardiac contractile dysfunction in the stunned myocardium.

Animals↗