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N Imai

Publications and source records attributed to N Imai.

At least 19 recordsLinked to original sources
PubMed2006

Observation of strong low-lying E1 strength in the two-neutron halo nucleus 11Li.

An exclusive measurement has been made of the Coulomb dissociation of the two-neutron halo nucleus 11Li at 70 MeV/nucleon at RIKEN. Strong low-energy (soft) E1 excitation is observed, peaked at about Ex = 0.6 MeV with B(E1) = 1.42(18) e2fm2 for Erel < or = 3 MeV, which was largely missed in previous measurements. This excitation represents the strongest E1 transition ever observed at such low excitation energies. The spectrum is reproduced well by a three-body model with a strong two-neutron correlation, which is further supported by the E1 non-energy-weighted cluster sum rule.

Journal Article↗
PubMed2006

Vanishing N = 20 shell gap: study of excited states in (27,28)Ne.

This Letter reports on the (1)H((28)Ne, (28)Ne) and (1)H((28)Ne, (27)Ne) reactions studied at intermediate energy using a liquid hydrogen target. From the cross section populating the first 2(+) excited state of (28)Ne, and using the previously determined BE(2) value, the neutron quadrupole transition matrix element has been calculated to be M(n)=13.8 +/- 3.7 fm(2). In the neutron knockout reaction, two low-lying excited states were populated in (27)Ne. Only one of them can be interpreted by the sd shell model while the additional state may intrude from the fp shell. These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in (27,28)Ne nuclei caused by a vanishing N=20 shell gap at Z=10.

Journal Article↗
PubMed2006

Inter-individual variation of cytochrome P4502J2 expression and catalytic activities in liver microsomes from Japanese and Caucasian populations.

The aim of this study was to investigate the inter-individual variations in cytochrome P4502J2 (CYP2J2) and its typical drug oxidation activities in human liver microsomes in both Japanese and Caucasian populations. CYP2J2 contents were determined immunochemically in liver microsomes from 20 Japanese and 29 Caucasian samples using recombinant CYP2J2 commercially available as a standard. Ebastine hydroxylation and astemizole O-demethylation activities were compared. The CYP2J2 genotype was determined by direct sequencing of liver genomic DNA. The mean expression levels of CYP2J2 determined immunochemically in liver microsomes from Japanese and Caucasian samples were 2.0 +/- 1.5 and 1.2 +/- 2.1 pmol CYP2J2 mg-1 protein (mean +/- standard deviation), respectively, accounting for 1.8 +/- 1.1% and 0.52 +/- 0.65% of the total hepatic P450 content (0.15 +/- 0.19 and 0.27 +/- 0.14 nmol P450 mg-1 protein, respectively). The individual variation of the two marker drug oxidation activities could not be fully accounted for by the CYP2J2 contents or currently known CYP2J2 genotypes. The amounts of CYP2J2 in liver microsomes with the CYP2J2*7 allele (-76G>T) were decreased to 39% compared with those of liver microsomes from other individuals. The results indicate that CYP2J2 accounts for approximately 1-2% of total P450 in human liver microsomes. The information about large inter-individual variation of the CYP2J2 suggests that this enzyme plays a significant role in the metabolism of xenobiotics and may be useful in in-silico simulations of drug disposition.

Adolescent↗
PubMed2006

Disease-specific expression of VEGF and its receptors in AML cells: possible autocrine pathway of VEGF/type1 receptor of VEGF in t(15;17) AML and VEGF/type2 receptor of VEGF in t(8;21) AML.

Various angiogenic factors, such as vascular endothelial growth factor (VEGF) and an associated molecule, placenta growth factor (PlGF), are thought to be important for normal and malignant hematopoiesis. This study examined mRNA expression of VEGF, PlGF and receptors for these molecules in AML cells and identified the disease-specific patterns of expression. AML M3 having t(15;17) abnormality showed highest expression of VEGF and VEGF receptor type 1 (VEGFR1), suggesting the autocrine pathway of VEGF-VEGFR1. Then, t(8;21) AML demonstrated augmented expression of VEGF and VEGF receptor type 2 (VEGFR2), suggesting VEGF-VEGFR2 autocrine pathway. Then, addition of VEGFR2 kinase inhibitor in Kasumi-1, a t(8;21) AML cell line, resulted in marked inhibition of cell growth, although growth inhibitory effect of R2 kinase inhibitor to HL-60 was marginal. In addition, cell cycle analysis study showed S-phase cell population reduction by R2 kinase inhibitor in Kasumi-1, but not in HL-60. This observation is thought to be the rationale for novel molecular target therapy directed to angiogenic molecules.

Adult↗
PubMed2006

Gene expression changes in a patient presenting nonleukaemic nasal granulocytic sarcoma to acute myelogenous leukaemia using 40 K cDNA microarray.

This is a case report of granulocytic sarcoma occurring as a nasal lesion prior to the onset of acute myelogenous leukaemia (AML). To understand this case in more detail, we used 40,000 human cDNA microarray to identify the gene expression patterns of nonleukaemic stage bone marrow (BM), AML stage BM and AML stage peripheral blood cells and subsequently define the molecular basis of this disease progression. Of significance, we have tracked the expression profile of BM samples during the course of nonleukaemic to leukaemic progression, and identified a number of genes that may account for the growth potential of leukaemia cells and indicate poor prognosis of this case.

Aged, 80 and over↗
PubMed2005

A ninety-day oral toxicity study of a new type of processed gum arabic, from Acacia tree (Acacia senegal) exudates, in F344 rats.

This study was designed to evaluate and characterize any subchronic toxicity of a new type of gum arabic (SUPER GUM [Acacia(sen)SUPER GUM]), a naturally processed polysaccharide exudate from gum acacia trees (Acacia senegal), when administered to both sexes of F344 rats at dietary levels of 0 (control), 1.25%, 2.5%, and 5.0% (10 rats/sex/group). During the study, the treatment had no effects on clinical signs, survival, body weights, and food and water consumption, or on findings of urinalysis, ophthalmology, hematology, or blood biochemistry. Gross pathology and histopathology exhibited no differences of toxicological significance between control and treated rats. Increased relative cecum (filled) weights, evident in both sexes of 5.0% group and females of 1.25% and 2.5% groups, were considered to be a physiological adaptation. Thus, the results indicated the toxic level of SUPER GUM to be more than 5.0%, and the no observed adverse effect level (NOAEL) was concluded to be 5.0% (3,117 mg/kg body weights/day for males, and 3,296 mg/kg body weights/day for males) from the present study.

Administration, Oral↗
PubMed2004

Bombyx mori nucleopolyhedrovirus orf8 encodes a nucleic acid binding protein that colocalizes with IE1 during infection.

This report describes the characterization of the Bombyx mori nucleopolyhedrovirus (BmNPV) orf8 gene. Immunoblot analyses demonstrated that orf8 was expressed as an early gene. The ORF8 protein accumulated in the nucleus, and was maintained at relatively constant levels from 4 to 24 h postinfection. Immunoblot analysis failed to detect ORF8 protein associated with budded virus and occlusion derived virus. In addition, immunohistochemical analysis by confocal microscopy showed that ORF8 protein colocalized with IE1 to specific nuclear foci throughout infection. To further examine the function of ORF8, a reporter gene was inserted into the orf8 reading frame. One orf8 disruption mutant (BmD8), which expressed the N-terminal half of ORF8, was isolated. However, it was not possible to isolate a null mutant, suggesting that orf8 may have an important role during viral infection. Single-step growth curves showed that BV production was reduced in BmD8 infected cells. Biochemical analyses indicated that ORF8 bound to nucleic acids. Together, these results suggest that BmNPV ORF8 may be involved in viral DNA replication and/or transcription.

Animals↗
PubMed2004

Anomalously hindered E2 strength B(E2;2+(1)-->0+) in 16C.

The electric quadrupole transition from the first 2(+) state to the ground 0(+) state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured mean lifetime is 77+/-14(stat)+/-19(syst) ps. The central value of mean lifetime corresponds to a B(E2;2+(1)-->0(+)) value of 0.63e(2) fm(4), or 0.26 Weisskopf units. The transition strength is found to be anomalously small compared to the empirically predicted value.

Journal Article↗
PubMed2004

28-Day repeated dose toxicity study of dried microorganism in rats.

Ubidecarenone, also known as CoQ(10), is currently sold as a dietary supplement in the United States, with a majority of these products derived from the fermentation of carbohydrates or tobacco leaf extracts. In addition to its availability in dietary supplements, CoQ(10) is now being considered for use in foods. Accordingly, as part of the process for attaining "Generally Recognized as Safe" status, and to supplement information already available regarding the safety of CoQ(10) per se, a 28-day oral toxicity study in rats was conducted to evaluate the subacute safety of a microorganism biomass used as a new source in CoQ(10) production. Groups of Crj:CD(SD) rats (SPF) (6 males or females per group, 4 groups per sex) received dried microorganism at doses of 0, 500, 1000 or 2000 mg/kg/day via intragastric intubation. Clinical observations were recorded, and body weight, and food and water consumptions measured throughout the study. At the end of the study, aortic blood samples were collected from all animals for analysis of hematological and clinical chemistry parameters, and gross pathologic examination was performed. Histopathologic examination was performed on select tissues from the control and high-dose groups. There were no treatment-related changes that were considered to be of toxicological significance. Since rats treated with 2000 mg/kg of dried microorganism did not demonstrate any treatment-related changes, the no-observable-adverse-effect level (NOAEL) for dried microorganism was estimated to be greater than 2000 mg/kg/day under the present study conditions.

Administration, Oral↗
PubMed2004

Pathological study on the relationship between C4d, CD59 and C5b-9 in acute renal allograft rejection.

In order to evaluate the activation or inhibition of the later phases of classical complement cascade in renal allograft presenting with acute rejection, particularly with C4d deposition on the peritubular capillary (PTC), we observed the expression of CD59 and C5b-9 on the PTC. Subjective cases were divided into two groups, an acute rejection group, of 4 males and 6 females, and a normal donor group, of 5 males and 5 females. Renal biopsies were performed at the onset of acute rejection and at the transplant operation, before reperfusion. C4d deposition on PTC was found in three of 10 cases (30%) with biopsy proven acute rejection, whereas CD59 on PTC was positively expressed in all of the rejection cases. Although C5b-9 was not observed on PTC in the acute rejection group, it was intensively deposited on the tubular basement membrane (TBM) in five cases, including the three with positive C4d on PTC. In the normal donor group, CD59 on PTC was intensively observed, whereas C5b-9 was weakly expressed on TBM. CD59, a complement regulatory factor, works as an inhibitory factor against the formation of C5b-9, a membrane attack complex. From our data, we noted the dissociation between the depositions of C4d and C5b-9 on PTC. The substantially expressed CD59 on PTC may affect this dissociation between C4d and C5b-9 on PTC. The intensive deposition of C5b-9 on TBM in acute rejection cases may suggest an independent immunological injury attacking tubular cells.

Acute Disease↗
PubMed2003

Determination of the subthreshold state contribution in 13C(alpha,n)16O, the main neutron-source reaction for the s process.

The reaction rate of the stellar reaction 13C(alpha,n)16O, which is currently considered to be the main neutron source for the slow (s) process at low energies, has been rederived using the direct alpha-transfer reaction 13C(6Li,d)17O leading to the subthreshold state at 6.356 MeV in 17O. The contribution of the subthreshold state is found to be much smaller than the currently accepted predictions for the main neutron source of the s process, indicating less of a role of this reaction as the neutron source for the s-process scenario in low-mass stars at the asymptotic giant branch.

Journal Article↗
PubMed2003

Interaction of Bombyx mori nucleopolyhedrovirus BRO-A and host cell protein laminin.

The Bombyx mori nucleopolyhedrovirus (BmNPV) contains five baculovirus repeated ORF ( bro) genes, all of which are expressed as delayed early genes. We have recently reported that BmNPV BRO proteins, specially BRO-A and BRO-C, contain a nucleic acid binding activity and are involved in nucleosome structures in nuclei of infected cells. To further understand the function of bro-a gene, we looked for factors interacting with BmNPV BRO-A using the yeast two-hybrid system. Fifteen clones obtained from a cDNA library of mock-infected cells and one from a library prepared at 2 h postinfection (p.i.) were found to comprise one distinct gene, which was identified as the Bombyx homolog (bLaminin) of Drosophila laminin beta1. A direct interaction between BRO-A and N-terminal region of bLaminin was demonstrated by in vitro pull-down experiments. Further pull-down assays using BmN cell extracts and anti-laminin antibodies also showed interaction of both proteins. In addition, two more clones were obtained from cDNA library of 12 h p.i. and were found to encode BRO-A itself, indicating that BRO-A forms an oligomer. Taken together, we propose that BRO-A may function as a laminin binding protein.

3' Flanking Region↗
PubMed2003

A thirteen-week oral toxicity study of annatto extract (norbixin), a natural food color extracted from the seed coat of annatto (Bixa orellana L.), in Sprague-Dawley rats.

A subchronic oral toxicity study of annatto extract (norbixin), a natural food color, was conducted. Groups of 10 male and 10 female Sprague-Dawley rats were fed annatto extract at dietary levels of 0, 0.1, 0.3 and 0.9% for 13 weeks. There were no treatment-related adverse effects on body weight, food and water consumption, ophthalmology and hematology data. Blood biochemical analysis revealed changes in rats of both sexes confined to the 0.9% and 0.3% groups, including increased alkaline phosphatase, phospholipid, total protein, albumin and albumin/globulin ratio. Marked elevation in absolute and relative liver weights was also found in both sexes of the 0.9% and 0.3% groups, but not the 0.1% group. Hepatocyte hypertrophy was evident and an additional electron microscopic examination demonstrated this to be linked to abundant mitochondria after exposure to a dietary level of 0.9% annatto extract for 2 weeks. Thus, the No-Observed-Adverse-Effect-Level (NOAEL) was judged to be a dietary level of 0.1% (69 mg/kg body weight/day for males, 76 mg/kg body weight/day for females) of annatto extract (norbixin) under the present experimental conditions.

Administration, Oral↗
PubMed2002

cDNA cloning of calcineurin heterosubunits from the pheromone gland of the silkmoth, Bombyx mori.

Pheromone biosynthesis activating neuropeptide (PBAN) stimulates the step of fatty acyl reduction in the pheromone biosynthetic pathway of the silkmoth, Bombyx mori. It has been suggested that the intracellular signal transduction of PBAN in B. mori involves Ca(2+), calmodulin, and calcineurin (also known as protein phosphatase 2B). We have cloned two cDNAs encoding calcineurin heterosubunits from a pheromone gland cDNA library of B. mori. The 2,996-bp clone predicts a 495-amino acid protein homologous to the catalytic subunit calcineurin A (CnA) with a molecular mass of 55,968. The deduced amino acid sequence well conserves the calcineurin B (CnB)-binding domain and two subdomains, a calmodulin-binding and an autoinhibitory domain, showing 77-85% and 82% identities to the isoforms of Drosophila melanogaster CnA and human CnA, respectively. On the other hand, the 820-bp clone predicts a 170-amino acid protein homologous to the regulatory subunit CnB with a molecular mass of 19,357. The deduced amino acid sequence well conserves four EF-hand type calcium-binding structures, showing 95% and about 85% identities to D. melanogaster CnB and mammalian CnBs, respectively. A yeast two-hybrid system has demonstrated the molecular interaction between B. mori CnA and CnB. Northern blot analyses revealed that both CnA and CnB genes were expressed in various larval and adult tissues of B. mori. Both transcripts detected in the pheromone gland three days before adult eclosion increased by the day before eclosion and the mRNA levels were found to be high even two days after adult eclosion. Immunohistochemical analysis has revealed that B. mori calcineurin is localized in the cytoplasm of the pheromone-producing cells.

Amino Acid Sequence↗
PubMed2002

Non-mutated tumor-rejection antigen peptides elicit type-I allergy in the majority of healthy individuals.

IgE-mediated type-I allergy is generally considered to be a hypersensitivity reaction to foreign antigens, and it is believed that self-antigens do not evoke this type of allergy. We report here, for the first time, that non-mutated self-antigen peptides identified as tumor-rejection antigen peptides recognized by HLA class I-restricted and tumor-specific cytotoxic T lymphocytes (CTLs) elicited a type-I allergy in the majority of healthy individuals. Peptide-specific IgE was detectable in sera from certain cases, although the levels did not always correlate with those of type-I allergy. Repeated vaccinations of nonallergic peptides derived from the same antigens possessing allergic peptides resulted in the suppression of both allergic peptide-specific IgE responses and type-I allergy, providing evidence for a new approach to the development of peptide-based desensitization.

Adult↗
PubMed2001

Identification of Lck-derived peptides capable of inducing HLA-A2-restricted and tumor-specific CTLs in cancer patients with distant metastases.

The Lck protein (p56(lck)), a src family tyrosine kinase essential for T cell development and function, is aberrantly expressed in various types of cancers. We revealed recently that Lck can be a tumor antigen recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes (CTLs) of cancer patients with metastases. In this study, we tried to identify Lck-derived epitopes capable of inducing HLA-A2-restricted and tumor-specific CTLs in cancer patients. The tumor-infiltrating lymphocytes (TILs) from 2 HLA-A2 cancer patients were found to respond to COS-7 cells when co-transfected with the lck gene and either HLA-A0201, -A0206, or A0207 cDNA. These TILs contained CTLs capable of recognizing either the Lck(61-69), the Lck(246-254), or the Lck(422-430) peptide among 24 different peptides, all of which were prepared based on the HLA-A2 binding motif. Importantly, in vitro sensitization with the latter 2 peptides induced tumor-specific CTLs in HLA-A2(+) cancer patients with metastases, but not in those without metastases. Overall, the Lck(246-254) and Lck(422-430) peptides could be useful for specific immunotherapy of HLA-A2(+) cancer patients, especially with distant metastases.

Animals↗
PubMed2001

Epidermal growth factor and 1alpha,25-dihydroxyvitamin D3 suppress lipogenesis in hamster sebaceous gland cells in vitro.

We have previously reported the establishment of a culture system of hamster auricular sebocytes. Although their morphologic and biochemical properties are very similar to those of human sebocytes, the regulation of lipogenesis is not clear. Therefore, we investigated the effect of epidermal growth factor, all-trans retinoic acid, 1alpha,25-dihydroxyvitamin D3, and androgens such as testosterone and 5alpha-dihydrotestosterone on lipogenesis in cultured hamster sebocytes. Intracellular lipid droplets detected with Oil-Red-O staining were observed in 5 d cultures and increased in a time-dependent manner; 40.7% +/- 1.11% of 2 wk cultured cells tested lipid-positive by flow cytometric analysis. When the hamster sebocytes were cultured in the presence of epidermal growth factor, all-trans retinoic acid, or 1alpha,25-dihydroxyvitamin D3, the intracellular lipid droplets were diminished by all-trans retinoic acid and epidermal growth factor, and slightly by 1alpha,25-dihydroxyvitamin D3. The intracellular lipid droplets consisted mainly of triglycerides (71.8%) and, as minor components, cholesterol (18.0%), wax esters (3.6%), and free fatty acids (6.6%). Epidermal growth factor and all-trans retinoic acid decreased the intracellular accumulation of triglycerides (92.6% and 96.1% inhibition, respectively) and free fatty acids (54.3% and 62.6% inhibition, respectively) in the sebocytes. In addition, 1alpha,25-dihydroxyvitamin D3 decreased the triglyceride level (34.3% inhibition), but augmented the accumulation of wax esters (30% increase). There was no difference in the level of cholesterol as a result of these treatments, however. In contrast, 5alpha-dihydrotestosterone augmented the formation of intracellular lipid droplets along with an increase in the accumulation of triglycerides in hamster sebocytes. Our findings that regulation of lipogenesis by all-trans retinoic acid and androgen in hamster sebocytes is identical to regulation in humans suggest that hamster sebocytes are useful for the elucidation of sebaceous function at the cellular level. Furthermore, this is the first evidence that epidermal growth factor and 1alpha,25-dihydroxyvitamin D3 may act as suppressors in the regulation of lipogenesis in hamster sebocytes in vitro.

Animals↗