Search PubMed⌕ Search

Biomedical subjects

M Fujiwara

Publications and source records attributed to M Fujiwara.

At least 109 records · Page 6Linked to original sources
PubMed2000

Nitric oxide-induced cGMP accumulation in the mouse bladder is not related to smooth muscle relaxation.

The functional role of nitric oxide (NO) and the guanylate cyclase/cGMP second messenger system was investigated in the mouse bladder. Electrical field stimulation and the NO-donor 3-morpholino-sydnonimin hydrochloride (SIN-1) did not induce relaxation of the carbachol-precontracted bladder. However, sodium nitroprusside (10(-3) M) was found to enhance the contractile response to electrical field stimulation by 24+/-6% (n=8; P<0.05) without affecting the contractile response to carbachol. The enhancement of bladder contractility evoked by sodium nitroprusside was inhibited by the guanylate cyclase inhibitor 1H-[1,2, 4]oxadiazolo[4,3-a]quinoxalime-1-one (ODQ; 10(-6) M). Incubation of bladder strips with SIN-1 and sodium nitroprusside caused an increase in cGMP accumulation as measured by radioimmunoassay. Immunohistochemical studies showed cGMP-immunoreactivity in nerve fibres and in stromal cells, but not in smooth muscle bundles after exposure to NO-donors. The results show that NO-donors have no inhibitory effect on smooth muscle tone in the mouse bladder, but that NO may have a functional role as an excitatory neuromodulator. The targets of endogenous NO in the bladder may be the demonstrated cGMP-positive structures, i.e., nerves and stromal cells.

Animals↗
PubMed2000

Soft dipole resonance in the neutron-skin nucleus 6He

A candidate for a soft dipole resonance, a dipole oscillation mode between a core cluster and a neutron skin, was observed at Ex = 4+/-1 MeV and with a width of 4+/-1 MeV in 6He via the 6Li( 7Li, 7Be) reaction at an incident energy of 65A MeV and forward scattering angles including 0 degrees. Its cross section is deduced to be sigma(0 degrees ) = 0.9+/-0.2 mb/sr. This value is comparable to that of the giant dipole resonance simultaneously measured.

Journal Article↗
PubMed2000

Cbfa1, an essential transcription factor for bone formation, is expressed in testis from the same promoter used in bone.

Cbfa1 is an essential transcription factor for bone formation, but its transcripts have also been detected in thymus and testis. To elucidate the expression of Cbfa1 in testis, we isolated Cbfa1 cDNA from mouse testis. First we examined the length of the transcripts expressed in mouse testis by Northern hybridization. Using a cDNA probe that can detect both Type-I and Type-II Cbfa1 (Type-I: originally reported as Pebp2alphaA by Ogawa et al.; Type-II: originally reported as til-1 by Stewart et al.), 1.8-kb transcripts were detected in testis, and larger transcripts (6.3 kb and 7.4 kb) in T-cell lines, thymus and bone. Using a Type-II specific probe (bone isoform-specific probe), surprisingly, 1.8-kb testis transcript(s) were detected as well as those (6.3 kb) found in bone. In addition, the transcription start site in mouse testis coincides with one of three start sites identified in bone. These results suggest that the testis transcript is generated from the same promoter of Type-II Cbfa1, which is thought to be active only in osteoblasts and some chondrocytes. Next, to define the difference in length of transcripts, we isolated the Cbfa1 cDNA from mouse testis. Sequence analysis of the cDNA showed that alternative splicing around exon 2 and poly-adenylation within exon 8 occurred in the testis isoform, which produce the smaller transcripts. These data revealed that testis Cbfa1 mRNA is transcribed from same promoter used in bones, but the post-transcriptional regulation is different between testis and skeletal tissues.

Animals↗
PubMed2000

NO(2)(+) nitration mechanism of aromatic compounds: electrophilic vs charge-transfer process

The nitration of methylnaphthalenes with NO(2)BF(4) and NOBF(4) was examined in order to shed light on the controversial aromatic nitration mechanism, electrophilic vs charge-transfer process. The NO(2)(+) nitration of 1,8-dimethylnaphthalene showed a drastic regioselectivity change depending on the reaction temperature, where ortho-regioselectivity at -78 degrees C and para-regioselectivity at 0 degrees C were considered to reflect the electrophilic and the direct or alternative charge-transfer process, respectively, because the NO(+) nitration through the same reaction intermediates as in the NO(2)(+) nitration via a charge-transfer process resulted in para-regioselectivity regardless of the reaction temperature. The NO(2)(+) nitration of redox potential methylnaphthalenes higher than 1,8-dimethylnaphthalene gave a similar ortho-regioselectivity enhancement to 1,8-dimethylnaphthalene at lower temperature, thus reflecting the electrophilic process. On the other hand, the NO(2)(+) nitration of redox potential methylnaphthalenes lower than 1,8-dimethylnaphthalene showed para-regioselectivity similar to the NO(+) nitration, indicating the direct or alternative charge-transfer process. In the presence of strong acids where the direct charge-transfer process will be suppressed by protonation, the ortho-regioselectivity enhancement was observed in the NO(2)(+) nitration of 1,8-dimethylnaphthalene, suggesting that the direct charge-transfer process could be the main process to show para-regioselectivity. These experimental results imply that the NO(2)(+) nitration proceeds via not only electrophilic but also direct charge-transfer processes, which has been considered to be unlikely because of the high energy demanding process of a bond coordination change between NO(2)(+) and NO(2). Theoretical studies at the MP2/6-31G(d) level predicted ortho- and para-regioselectivity for the NO(2)(+) nitration via electrophilic and charge-transfer processes, respectively, and the preference of the direct charge-transfer process over the alternative one, which support the experimental conclusion

Journal Article↗
PubMed2000

Search for isovector giant monopole resonances via the Pb(3He,tp) reaction

The (nat)Pb(3He,tp) reaction at E(3He) = 177 MeV was studied to identify 2Planck's over 2piomega isovector monopole strength in Bi isotopes. Monopole strength was found in the region -45<Q<-30 MeV in the coincidence data. The cross section is compared with distorted-wave Born approximation calculations for non-spin-flip and spin-flip isovector monopole resonances. The observed spin-flip and non-spin-flip monopole strengths in the proton-decay channel amount to 20% of the respective non-energy-weighted sum rule.

Journal Article↗
PubMed2000

Spontaneous oscillation of oxy- and deoxy- hemoglobin changes with a phase difference throughout the occipital cortex of newborn infants observed using non-invasive optical topography.

We investigated spontaneous changes in the cerebral oxygenation state of infants during quiet sleeping by using a form of multi-channel near-infrared spectroscopy: non-invasive optical topography. Eight infants born at 32-39 weeks were studied at postconceptional term age (38-43 weeks). Spatially synchronized oscillations of changes in the concentration of oxy- and deoxy- hemoglobin ([oxy-Hb] and [deoxy-Hb]) were observed throughout the occipital cortex. Time series analysis based on the theory of non-linear oscillators showed that the mean periods of the oscillation for each infant ranged from 11 to 18 s. The phase lag of [oxy-Hb] relative to [deoxy-Hb] was stable at about 3pi/4. This phase difference may result from interplay between the vasomotion and the oxygen consumption in relation to brain activity.

Female↗
PubMed2000

Cellular senescence of a human bladder carcinoma cell line (JTC-32) induced by a normal chromosome 11.

Human chromosome 11 is expected to carry tumor suppressor genes for a variety of human cancers, including bladder carcinoma. To examine the functional role of a putative tumor suppressor gene(s) on this chromosome in the development of bladder carcinoma, we performed microcell-mediated transfer of chromosome 11 into the bladder carcinoma cell line, JTC-32. Fifteen of 20 colonies formed by the transfer experiment showed a remarkable change in cell morphology. They flattened and ceased growing, or senesced, prior to 10 population doublings. The presence of transferred chromosome 11-derived fragments in the growth-arrested cells was confirmed by PCR-based polymorphism analyses. The remaining 5 microcell hybrid clones exhibited a parental cell-like morphology, and presumably escaped from senescence, which was accompanied by deletions and/or rearrangements of the transferred chromosome 11. On the other hand, a transferred normal chromosome 7 neither changed the cell morphology nor arrested the cell growth. These results support the hypothesis that chromosome 11 contains a gene or genes which restore the senescence program lost during the immortalization process of JTC-32 cells.

Aged↗
PubMed2000

Suppression of hepatic lesions in a murine graft-versus-host reaction by antibodies against adhesion molecules.

BACKGROUND/AIMS: The injection of parental CD4+ T cells into major histocompatibility complex (MHC) class II disparate F1 hybrid mice induced an autoimmune graft-versus-host reaction (GVHR) which is analogous to autoimmune liver diseases. The interaction of adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) and very late antigen-4 (VLA-4) has been known to be profoundly involved in the trafficking of lymphocytes into the inflammatory tissues. The aim of this study was to clarify the role of VLA4 or VCAM-1 in the development of GVHR-induced hepatic lesions in our model. METHODS: B6 T spleen cells were injected into (B6.C-H-2bm12xB6) F1 mice intravenously. Anti-VLA-4 mAbs and/or anti-VCAM-1 mAbs were injected intraperitoneally at a dose of 2.5 mg/kg of each mAbs per body weight of mouse. We examined the changes in GVHR-induced hepatic lesions, serum levels of antimitochondrial antibodies (AMA) and cytokine mRNA expressions of liver-infiltrating lymphocytes using H.E. and immunohistochemical staining, enzyme-linked immunosorbent assay (ELISA), and reverse transcription-polymerase chain reaction (RT-PCR), respectively. RESULTS: Hepatic lesions of anti-VLA-4 mAbs-treated mice were inhibited compared with those of GVHR mice. However, the administration of mAbs did not interfere with the induction of splenomegaly, the invasion of CD4+, CD8+, B220+, or Mac-1+ cells around bile ducts, nor the production of AMA. Liver-infiltrating CD4+ T cells obtained from these treated mice did not alter the expression of T helper (Th)1 and Th2 cytokine mRNA. CONCLUSION: The results suggest that treatment with antibodies against these adhesion molecules could inhibit the infiltration of lymphocytes without affecting the Th1/Th2 balance. The blockade of VLA-4-mediated cell infiltration into the liver in this model may have a possible novel therapeutic role of VLA-4 mAbs.

Animals↗
PubMed2000

Telomerase activity significantly correlates with chromosome alterations, cell differentiation, and proliferation in lung adenocarcinomas.

Telomerase activity was examined by the telomeric repeat amplification protocol assay in 25 cases of lung adenocarcinoma, in relation to cancer cell differentiation, proliferation, and chromosome alterations. Telomerase activity, chromosome alterations, and cell proliferation assessed by Ki-67 labeling were significantly lower (P < .001 to .05) in well-differentiated (10 cases) than in moderately differentiated (8 cases) or poorly differentiated (7 cases) lesions. Telomerase activity by semiquantitative analysis with scoring of 0 to 3 was significantly correlated with similarly graded chromosome alterations (P < .05) and Ki-67 labeling indices (P < .002). Telomerase activity and chromosome alteration (T-C) indices generated by multiplication of telomerase activity and chromosome alteration scores also showed a significant correlation with cell differentiation. The Clara cell subtype, confirmed by electron microscopic analysis, significantly predominated in the well-differentiated group, showing a low grade of telomerase activity and chromosome alterations and low Ki-67 labeling indices, suggesting clinical relevance. No significant association of telomerase activity was found with p53 protein accumulation or Bcl-2 protein expression. The good correlation of telomerase activity with chromosome alterations, cell differentiation, and Ki-67 labeling indices suggests that this parameter might have potential application in estimation of prognosis.

Adenocarcinoma↗
PubMed2000

CD14+CD16+ monocyte subpopulation in Kawasaki disease.

Kawasaki disease (KD) is an acute febrile illness caused by vasculitis, occurring in early childhood. We have demonstrated that the activation of monocytes/macrophages plays a central role during acute KD. Recently, it has been reported that the CD14+CD16+ monocyte subpopulation plays a more important role in inflammation. In this study, we investigated the peripheral blood CD14+CD16+ monocyte subpopulation by flow cytometry, and serum levels of IL-10 and IL-12 using a sandwich ELISA in 28 KD patients. We also investigated this subpopulation in patients with bacterial infections, mononucleosis and anaphylactoid purpura, since the cause of KD remains unknown. We observed an increase in the number of CD14+CD16+ monocytes with acute KD, which was a positive correlation with C-reactive protein levels, and we observed only the patients with severe bacterial infections had increased this subpopulation during the acute stage among control diseases. In addition, we found that the serum levels of IL-10, but not IL-12, were higher during acute KD. These data suggest that increased peripheral blood CD14+CD16+ monocytes are part of the regulatory system of monocyte function during acute KD.

Acute Disease↗
PubMed2000

Cytokine profile of liver-infiltrating CD4+ T cells separated from murine primary biliary cirrhosis-like hepatic lesions induced by graft-versus-host reaction.

BACKGROUND AND METHODS: We have previously reported that CD4+ T cells induced primary biliary cirrhosis (PBC)-like hepatic lesions in mice with graft-versus-host reaction due to major histocompatibility complex class II disparity. To clarify the relationship between the cytokine profile produced by CD4+ T cells and the formation of hepatic lesions, we sorted CD4+ T cells from the liver by using flow cytometry and examined their cytokine mRNA expression at various times after GVHR induction. We also examined the associated changes in the serum levels of antimitochondrial antibodies (AMA). RESULTS: Histologically, the infiltration of CD4+ T cells around the bile ducts was observed from day 5, and the lesions deteriorated gradually until day 14. On day 14, CD8+, B220+ and Mac-1+ cells, as well as CD4+ T cells were seen around the bile ducts. In the liver-infiltrating CD4+ T cells, the expression level of interferon-gamma (IFN-gamma) mRNA was observed to increase at an early phase (day 3), whereas that of interleukin (IL)-10 mRNA was elevated at a later phase (day 14). The elevation of IFN-gamma mRNA expression at an early phase before the appearance of non-suppurative destructive cholangitis suggests that IFN-gamma may be related to the pathogenesis of PBC in this model. Serum levels of AMA on day 14 were significantly higher than those on day 5. Interleukin-10 was considered to stimulate antibody production, to show an inhibitory effect upon the function of T helper 1 cells, and to inhibit fibrosis. CONCLUSIONS: Interferon-gamma may play an important role in the pathogenesis of this model. Moreover, delayed expression of IL-10 mRNA may control PBC-like hepatic lesions.

Animals↗
PubMed2000

Mosaic-like distribution of endothelial cell antigens in capillaries and juxta-alveolar microvessels in the normal human lung.

The distribution patterns of endothelial cell antigens, including thrombomodulin and von Willebrand factor (vWf), were studied in normal lung tissues obtained from distant areas of solitary nodules (seven adenocarcinomas and four hamartomas). By single immunoalkaline phosphatase and dual immunofluorescence stainings, the plasma membranes of alveolar capillary endothelium showed linear distribution of thrombomodulin, but their cytoplasm was rarely reactive for vWf (thrombomodulin-dominant pattern). Microvessels with a diameter larger than 10 microm located in the connective tissue zones demonstrated band-like reaction for vWf in their cytoplasm, and their plasma membranes often lacked reactivity for thrombomodulin (vWf-dominant pattern). The juxta-alveolar microvessels located along the borders between the alveolar- and connective-tissue zones showed mosaic-like pattern of distribution for these antigens. The pulmonary venules and peribronchial microvessels measuring up to 40 microm in diameter, demonstrated the expression of thrombomodulin along the plasma membrane, and that of vWf in the cytoplasm. Capillaries of the bronchial circulation were also characterized by mosaic-like pattern of distribution. Both antigens were often expressed in a single cytoplasmic segment. The heterogeneous distribution pattern of these antigens suggests topographic difference in endothelial cell function to maintain coagulatory and anticoagulatory balance in the normal human lung.

Adult↗
PubMed2000

Survival factors in digital replantation: significance of postoperative anaemia.

Two hundred and fifty-two consecutive digital replantations and revascularizations in 201 patients were retrospectively reviewed to determine factors influencing survival. Children under 9 years of age, women, complete amputations, blood transfusions and secondary thrombectomy were poor prognostic factors. In addition, low haemoglobin and haematocrit levels during the postoperative period were associated with a higher failure rate. Inappropriate use of anticoagulants and excessive postoperative anaemia should be avoided following replantation.

Adult↗
PubMed2000

Telomere shortening with aging in human liver.

Progressive telomere shortening with aging was studied in the normal liver tissue of 94 human subjects aged between 0 and 101 years old to determine the rate of telomere loss in 1 year. Telomere length demonstrated accelerated shortening with reduction of 55 base pairs (bp) per year. The mean telomere length in five neonates was 12.9 +/- 2.6 kilobase pairs (kbp), and that in one centenarian was 8.3 kbp. Mean telomere lengths by age group were 13.2 +/- 2.0 kbp (< or = 8 years; 10 subjects), 7.8 +/- 1.9 kbp (40-79 years; 29 subjects), and 7.5 +/- 2.0 kbp (> or = 80 years; 53 subjects), with reduction thus appearing to show slowing on the attainment of middle age. The difference of mean telomere lengths for two groups with or without advanced malignancies of other than liver origin was not significant in the older two groups. Despite the slow turnover of liver tissue, the overall reduction rate of telomere length decrease in 1 year was almost the same as that of digestive tract mucosa, with its very rapid renewal.

Adolescent↗
PubMed2000

Evidence that the Aspergillus nidulans class I and class II chitin synthase genes, chsC and chsA, share critical roles in hyphal wall integrity and conidiophore development.

Although many chitin synthase genes have been identified in a broad range of fungal species, there have been only a few reports about their role in fungal morphogenesis. In most cases, single gene disruption or replacement did not reveal their function, possibly because of functional redundancy among them. We obtained null mutants of Aspergillus nidulans chsA and chsC genes encoding non-essential class II and class I chitin synthases, respectively. The DeltachsA DeltachsC mutant exhibited growth defects on media supplemented with sodium dodecyl sulfate (SDS), high concentration of salts, chitin-binding dyes, or chitin synthase competitive inhibitors, suggesting loss of integrity of hyphal wall. Moreover, remarkable abnormalities of the double mutant were observed microscopically during its asexual development. The conidiophore population was drastically reduced. Interestingly, secondary conidiophores were occasionally produced from vesicles of the primary ones. The morphology of these conidiophores was similar to those of the A. nidulans developmental mutants, medusa (medA), abacus (abaA), and some kinds of bristle (brlA). In situ staining patterns suggested that chsA was mainly expressed in the metulae, phialides, and conidia, whereas chsC was expressed in hyphae as well as conidiophores. These results suggest that ChsA and ChsC share critical functions in hyphal wall integrity and differentiation.

Aspergillus nidulans↗
PubMed2000

The role of structural intersubunit microheterogeneity in the regulation of the activity in hysteresis of ribulose 1, 5-bisphosphate carboxylase/oxygenase.

Many enzymes are composed of subunits with the identical primary structure. It has been believed that the protein structure of these subunits is the same. Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) comprises eight large subunits with the identical amino acid sequence and eight small subunits. Rotation of the side chains of the lysine residues, Lys-21 and Lys-305, in each of the eight large subunits in spinach RuBisCO in two ways produces microheterogeneity among the subunits. These structures are stabilized through hydrogen bonds by water molecules incorporated into the large subunits. This may cause different effects upon catalysis and a hysteretic, time-dependent decrease in activity in spinach RuBisCO. Changing the amino acid residues corresponding to Lys-21 and Lys-305 in non-hysteretic Chromatium vinosum RuBisCO to lysine induces hysteresis and increases the catalytic activity from 8.8 to 15.8 per site per second. This rate is approximately five times higher than that of the higher-plant enzyme.

Catalysis↗
PubMed2000

Chloroplast targeting, distribution and transcriptional fluctuation of AtMinD1, a Eubacteria-type factor critical for chloroplast division.

In Arabidopsis thaliana, a mature mesophyll cell contains approximately 100 chloroplasts. Although 12 arc mutants (accumulation and replication of chloroplasts) and two chloroplast division genes homologous to eubacterial ftsZ have been isolated from A. thaliana, the molecular mechanism underlying the chloroplast division is still unclear. We characterized AtMinD1, a eubacterial minD homolog, for chloroplast division in A. thaliana. AtMinD1-green fluorescent protein targeted to the chloroplasts and possibly associated with the envelope membranes in vivo. During the seed germination, the AtMinD1 transcripts were accumulated twice, just after release from cold treatment and at the beginning of rapid greening, in similar fashion to AtFtsZs. Furthermore the transcript level in a severest chloroplast division mutant, arc6, was 3-5-fold higher than that in wild-type.

Amino Acid Sequence↗