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H Uchida

Publications and source records attributed to H Uchida.

At least 37 records · Page 2Linked to original sources
PubMed2001

Polymerization of bisphenol A by purified laccase from Trametes villosa.

The metabolism of bisphenol A (BPA), an endocrine-disrupting chemical, was studied with a highly purified laccase from the basidiomycete Trametes villosa. The enzyme reaction products ranged widely from water-insoluble to -soluble compounds, one of which was previously identified as 4-isopropenylphenol. (1)H NMR and electron-impact mass spectrum analyses showed that one of the insoluble products was a BPA dimer, 5,5'-bis-[1-(4-hydroxy-phenyl)-1-methyl-ethyl]-biphenyl-2,2'-diol. Field-desorption mass spectrum analysis revealed BPA oligomers, some of which contained phenol, within the insoluble fraction. These results indicate that the laccase reaction may contain successive BPA polymerization, followed by either the addition of phenol to the formed oligomers or their decomposition to release 4-isopropenylphenol.

Benzhydryl Compounds↗
PubMed2001

Green fluorescent protein-transgenic rat: a tool for organ transplantation research.

The purpose of this study is to evaluate green fluorescent protein (GFP) transgenic rats for use as a tool for organ transplantation research. The GFP gene construct was designed to express ubiquitously. By flow cytometry, the cells obtained from the bone marrow, spleen, and peripheral blood of the GFP transgenic rats consisted of 77, 91, and 75% GFP-positive cells, respectively. To examine cell migration of GFP-positive cells after organ transplantation, pancreas graft with or without spleen transplantation, heart graft with or without lung transplantation, auxiliary liver and small bowel transplantation were also performed from GFP transgenic rat to LEW (RT1(1)) rats under a 2-week course of 0.64 mg/kg tacrolimus administration. GFP-positive donor cells were detected in the fully allogenic LEW rats after organ transplantation. These results showed that GFP transgenic rat is a useful tool for organ transplantation research such as cell migration study after organ transplantation without donor cell staining.

Animals↗
PubMed2001

Activation of the p21(CIP1/WAF1) promoter by bone morphogenetic protein-2 in mouse B lineage cells.

BMPs exert a negative growth effect on various types of cells. We have previously reported that BMP-2 inhibited the growth of HS-72 mouse hybridoma cells by inducing p21(CIP1/WAF1) expression. In the present study, we demonstrated that BMP-2 activated the mouse p21(CIP1/WAF1) promoter in HS-72 cells, and that a 29-base pair (b) region of the promoter (-1928/-1900 relative to the TATA box), conserved between mice and humans, was responsive to BMP-2 as well as expression of Smad1, Smad4, and constitutively active mutants of BMP type I receptors. Furthermore, an oligonucleotide containing the 29-b region was found to be associated with Smad4 and phosphorylated Smad1 in the nuclear extract of BMP-2-stimulated HS-72 cells. These results suggested that BMP-2 might activate p21(CIP1/WAF1) transcription by inducing a binding of Smad4 and Smad1 to the 29-b region in HS-72 cells.

Animals↗
PubMed2001

Degradation of bisphenol A by purified laccase from Trametes villosa.

Degradation of bisphenol A (BPA), an endocrine-disrupting chemical, was studied with a purified laccase from the basidiomycete Trametes villosa. SDS--polyacrylamide gel electrophoresis of the purified laccase gave one single band with a mobility corresponding to MW 65 kDa. The absorption spectrum showed the characteristics of a blue copper protein with a maximum peak at 600 nm. HPLC analysis revealed that 2.2 micromol BPA were degraded by incubation with 1.5 units of the purified laccase in a total volume of 1.0 ml at pH 6.0 and 60 degrees C for 3 h. The enzyme reaction proceeded rapidly without requirement of mediators for the electron transfer. Isolation and identification of several reaction products are in progress, in which one product was identified as 4-isopropenylphenol by a gas chromatography--mass spectrophotometer.

Benzhydryl Compounds↗
PubMed2001

PAG3/Papalpha/KIAA0400, a GTPase-activating protein for ADP-ribosylation factor (ARF), regulates ARF6 in Fcgamma receptor-mediated phagocytosis of macrophages.

The Fcgamma receptor (FcgammaR)-mediated phagocytosis of macrophages is a complex process where remodeling of both the actin-based cytoskeleton and plasma membrane occur coordinately. Several different families of small GTPases are involved. We have isolated a GTPase-activating protein (GAP) for ADP-ribosylation factor (ARF), paxillin-associated protein with ARFGAP activity (PAG)3/Papalpha/KIAA0400, from mature monocytes and macrophage-like cells. Mammalian ARFs fall into three classes, and the class III isoform (ARF6) has been shown to be involved in FcgammaR-mediated phagocytosis. Here we report that PAG3 is enriched together with ARF6 and F-actin at phagocytic cups formed beneath immunoglobulin G-opsonized beads in P388D1 macrophages, in which overexpression of ARF6, but not ARF1 (class I) or ARF5 (class II), inhibits the phagocytosis. Overexpression of PAG3, but not its GAP-inactive mutant, attenuated the focal accumulation of F-actin and blocked phagocytosis, although surface levels of the FcgammaRs were not affected. Other ubiquitously expressed ARFGAPs, G protein-coupled receptor kinase interactors GIT2 and GIT2-short/KIAA0148, which we have shown to exhibit GAP activity for ARF1 in COS-7 cells, did not accumulate at the phagocytic cups or inhibit phagocytosis. Moreover, cooverexpression of ARF6, but not ARF1 or ARF5, restored the phagocytic activity of PAG3-overexpressing cells. We propose that PAG3 acts as a GAP for ARF6 and is hence involved in FcgammaR-mediated phagocytosis in mouse macrophages.

ADP-Ribosylation Factor 6↗
PubMed2001

Orthotopic intestinal transplantation using the cuff method in rats: a histopathological evaluation of the anastomosis.

Segmental small intestine transplantation (SIT) in rats, using a cuff technique, has achieved a high success rate. However, there have been few reports on the influence of the foreign body reaction to polyethylene cuff on vessel anastomoses and graft after SIT. This study involves the histopathological examination of the site of cuff anastomosis and grafts in the short- and long-term survival of segmental SIT. The data obtained from the suture anastomosis model also served as a control. One week after heterotopic segmental SIT using the cuff technique, orthotopic continuations were carried out in syngeneic combination. Twenty-five of 30 rats surviving >200 days (83.3%) were examined for vessel anastomosis. All arterial anastomoses were patent, but the portovenous anastomoses in 10 grafts (33%) were totally occluded and were associated with the formation of collateral vessels. Histopathological examination demonstrated good patency of the artery and vein anastomotic site in the short term, but granulation, fibrosis, and neovascularization at the anastomosis site surrounding the cuffs in the long-surviving group. However, the grafts appeared to be intact, with normal features of the villi. On the contrary, the site of the sutured anastomosis in the long-survival rats showed no inflammatory reaction. Although a polyethylene cuff caused foreign body reaction, the graft blood supplies were maintained by collateral vessels. Considering the low mortality and high success rate, polyethylene cuff is good for short-term study and an alternative method for long-term SIT experiments.

Anastomosis, Surgical↗
PubMed2001

Simplified method of heterotopic rat heart transplantation using the cuff technique: application to sublethal dose protocol of methotrexate on allograft survival.

Rodent heterotopic heart transplantation (HHT) models have been developed for the study of transplantation immunology. Most of these transplantations are performed by hand-suture techniques, requiring several months of training. We describe a modified technique of rat HHT in the neck, using a cuff method that can be mastered by beginners within a few weeks. Our main modification of the rat HHT in the neck is that the right superior vena cava of the graft is chosen as an outflow duct, while the pulmonary artery has been taken as an effluent drainage in the ordinary HHT models. The aorta of the donor is anastomosed with the carotid artery of the recipient. Donation can be completed within 5 min and vascular connections in the recipient done within 3 min, resulting in a minimum of ischemia time. Using this minimum surgical intervention model, we tested the immunosuppressive effect of a sublethal dose of methotrexate (MTX), which has been widely used in cancer therapy. Our results showed that high doses of MTX severely suppressed the recipient bone marrow, but prolonged heart allografts for more than 365 days after HHT. In conclusion, the new model simplified the rat HHT procedure and made it possible for the beginner of rodent transplantation to master this skill within a few weeks. Using this minimized intervention technique, we found that the high doses of MTX can significantly prolong the survival of fully mismatched DA heart graft in PVG/c recipient.

Animals↗
PubMed2001

Rat auxiliary liver transplantation without portal vein reconstruction: comparison with the portal vein-arterialized model.

Auxiliary liver transplantation (ALT) has been reintroduced in clinical cases recently and is now believed to be a viable alternative to orthotopic liver transplantation. To provide a simple rat ALT model for studying the physiological and immunological aspects of the ALT graft, a new ALT was performed, and the comparison between this new model and the portal arterialized one that was reported by other investigators was carried out. At first, we confirmed that liver could tolerate the deprivation of its portal flow well, using a portosystemic shunted rat model. The new rat ALT model, in which the ALT graft obtained its blood inflow only from the hepatic artery, was then performed. Our results demonstrated that 50% of the hepatic artery-alone ALT graft showed almost normal structure histologically at 1 month after grafting, with bile secretion preserved. By contrast, only 8% 1-month graft survival was noted in the portal arterialized group, and all grafts stopped bile secretion 1 week after operation. In conclusion, with arterial blood supply alone, the ALT graft survived and demonstrated normal bile secretion function for more than 1 month. Portal vein arterialization is not an appropriate way to establish the graft's blood supply if no pressure adjustment measures were taken in advance.

Animals↗
PubMed2001

Real-time [11C]methionine translocation in barley in relation to mugineic acid phytosiderophore biosynthesis.

[11C]Methionine was supplied through barley roots and the 11C signal was followed for 90 min using a real-time imaging system (PETIS), with subsequent development of autoradiographic images of the whole plant. In all cases, [11C]methionine was first translocated to the 'discrimination center', the basal part of the shoot, and this part was most strongly labeled. Methionine absorbed by the roots of the plants was subsequently translocated to other parts of the plant. In Fe-deficient barley plants, a drastic reduction in [11C]methionine translocation from the roots to the shoot was observed, while a greater amount of 11C was found in the leaves of Fe-sufficient or methionine-pretreated Fe-deficient plants. Treatment of Fe-deficient plants with aminooxyacetic acid, an inhibitor of nicotianamine aminotransferase, increased the translocation of [11C]methionine to the shoot. The retention of exogenously supplied [11C]methionine in the roots of Fe-deficient barley indicates that the methionine is used in the biosynthesis of mugineic acid phytosiderophores in barley roots. This and the absence of methionine movement from shoots to the roots suggest that the mugineic acid precursor methionine originates in the roots of plants.

Aminooxyacetic Acid↗
PubMed2001

Morphometric characteristics of optic disk with disk hemorrhage in normal-tension glaucoma.

PURPOSE: To evaluate the morphometric characteristics of the optic disk in eyes with and without disk hemorrhage in normal-tension glaucoma. METHODS: This was a prospective study conducted at Gifu University Hospital of 50 eyes of 50 patients with normal-tension glaucoma (12 men, 38 women; age, 56.5 +/- 14.1 years) who had developed new disk hemorrhage at the time of enrollment and 58 eyes of 58 patients with normal-tension glaucoma (20 men, 38 women; age, 56.7 +/- 12.4 years) with no history of disk hemorrhage during the follow-up period of more than 2 years. Age and global indexes of the visual field were matched. We morphometrically compared the optic disk with and without hemorrhage using a scanning laser tomograph. Global and sector analyses were made of the optic disk structural parameters. RESULTS: There was no significant difference in the global values of the disk parameters between the disk hemorrhage and the nonhemorrhage groups. However, the inferotemporal values for the rim area, rim volume, mean retinal nerve fiber layer thickness, and retinal nerve fiber layer cross-section area in the disk hemorrhage group were significantly smaller than those in the nonhemorrhage group (P <.05). In the disk hemorrhage group, moreover, the values for the rim area, rim volume, and retinal nerve fiber layer cross-section area in the inferotemporal sector with hemorrhage were significantly smaller than those in the same sector without hemorrhage (P <.05). CONCLUSION: Localized damage of the disk rim and retinal nerve fiber layer at the inferotemporal sector was prominent in eyes with disk hemorrhage.

Female↗
PubMed2001

Detection of early venous filling in gliomas on MRI: preliminary study by 2D time-resolved dynamic contrast-enhanced MR angiography with echo-sharing technique.

We evaluated the detection of early venous filling of gliomas by 2D time resolved dynamic contrast enhanced MR digital subtraction angiography (MR-DSA) with echo-sharing technique and compared the results with those of conventional contrast digital subtraction angiography (C-DSA). C-DSA and MR-DSA examinations were performed in eight patients with malignant gliomas and compared with regard to the visualization of early filling veins; time intensity curves of arteries, early filling veins and normal veins were made, and rise time and time to peak were evaluated. MR-DSA visualized 12 out of 17 early filling veins depicted on C-DSA. The failure of five veins to be depicted may be due to the overlapping of other structures, such as other vessels and tumor stain. On time intensity curves, the mean difference in rise time was 0.9 sec between the artery and early filling vein, and the mean difference of time to peak was 1.6 sec. C-DSA has been the modality of choice in demonstrating early venous filling, a useful finding in the differential diagnosis of gliomas. However the high temporal resolution of MR-DSA with echo-sharing technique provides sufficient visualization of early venous filling of gliomas. Additional information for precise differential diagnosis may be obtained by adding MR-DSA to the imaging protocol for gliomas.

Aged↗
PubMed2001

High-dose tacrolimus and lengthy survival of the combined rat pancreas/spleen graft in a high-responder combination.

Pancreas grafts do not survive for lengthy periods, especially in a high-responder rat combination. Recent data indicated that a combined spleen/pancreas graft protects against acute graft rejection and induces donor-specific tolerance. In this study, we performed a combination spleen/pancreas transplantation using high-dose tacrolimus in a high-responder rat combination of DA (RT1a) to LEW (RT1) and induced permanent survival in the few recipient rats. In these recipients, there was no difference in the mixed lymphocyte reaction (MLR) of the recipients when compared with that of the naive LEW splenic cells, but MLR inhibition by the serum from the recipients was significantly decreased. We also performed immunoblotting and detected a protein that has an affinity for the anti-DA class antibody. This protein may be an anti-idiotypic antibody and contribute to donor- and tissue-specific tolerance.

Animals↗
PubMed2001

Adrenomedullin suppresses fMLP-induced upregulation of CD11b of human neutrophils.

In this study we investigated the effect of adrenomedullin (AM) on fMLP-mediated activation of human neutrophils. AM partially, but significantly, suppressed fMLP-induced upregulation of CD11b expression. The inhibitory effects of AM upon fMLP-induced upregulation of CD11b expression were completely blocked by CGRP [8-37], a CGRP receptor antagonist. AM significantly increased cAMP content in neutrophils and SQ-22,536, an adenylate cyclase inhibitor, and KT-5720, a PKA inhibitor, significantly blocked the inhibitory effects of AM upon fMLP-induced upregulation of CD11b expression. This study indicates that binding of AM to the CGRP receptor suppresses fMLP-induced upregulation of CD11b expression of human neutrophils by increasing intracellular cAMP levels. AM may play an important role in the regulation of inflammatory processes, especially in the binding of neutrophils to vascular endothelial cells and subsequent neutrophil emigration evident in acute pulmonary inflammation.

Adenine↗
PubMed2001

Experimental small bowel transplantation using newborn intestine in rats: III. Long-term cryopreservation of rat newborn intestine.

BACKGROUND: If long-term organ cryopreservation can be attained, a significant achievement will have been made to address the problem for donor shortage. Fetal intestine has been known to revascularize naturally without vascular anastmosis. The authors have confirmed previously that the newborn intestine also could develop to maturity in the host omentum. Here, the authors examined whether the cryopreserved newborn intestine could revascularize in the syngeneic combination using the 2 different solutions and whether cryopreservation affect their antigenicity in the allogeneic combination. METHODS: Inbred rat strains of LEW (MHC haplotype; RT1(l)) and BN (RT1(n)) were used. LEW newborn intestinal grafts were stored in RPMI-1640 or University of Wisconsin solution with 10% DEMSO (n = 10 in each group). The grafts were placed into a cold (4 degrees C) preservation solution for 30 minutes and then placed into a freezing chamber and cooled to -80 degrees C at -1 degrees C/min after 12 hours quenched to -180 degrees C in liquid nitrogen for longer than 30 days. Then, the cryopreserved grafts under the 2 different solutions were transplanted syngenicaly (LEW to LEW). The cryopreserved BN grafts also were implanted into the LEW omentum pouch. The allotransplantation was received with a 14-day high-dose course of tacrolimus (0.64 mg/kg, intramuscularly). The grafts were evaluated histologically at 4 weeks after transplantation. Fresh newborn intestines implanted in this syngeneic and allogeneic combination were evaluated as each control group. RESULT: In the syngeneic combination, more than 90% of the mature intestine were obtained. There was no significant difference among the different solution and the fresh group. However, in the allogeneic combination, both fresh and cryopreserved grafts were histologically poor. CONCLUSIONS: This is the first report showing that long-term cryopreservation was not harmful for neovascularization of newborn intestine. Long-term cryopreservation did not reduce the antigenicity of the newborn intestine. J Pediatr Surg 36:602-604.

Animals↗
PubMed2001

Experimental small bowel transplantation using a newborn intestine in rats: IV. Effect of cold preservation on graft neovascularization.

BACKGROUND/PURPOSE: University of Wisconsin (UW) solution is one of the most superior organ preservation solutions for liver, kidney, and pancreas; however, it still is controversial for intestinal preservation. Here, the authors studied the efficacy of preservation with 2 kinds of solutions, UW and modified TOM (m-TOM) solutions in our experimental newborn intestinal transplantation model. UW solution was used as a standard intracellular and m-TOM solution as an extracellular preservation solution. Lactated ringer (LR) solution was used as a control. METHODS: Newborn intestine, which were preserved in these solutions for 24 or 48 hours, were transplanted in the subcutaneous spaces of the syngeneic recipients without surgical vascular anastomosis and histologically examined 14 days after grafting. The preserved grafts were evaluated histologically by use of light and electron microscopy just after preservation. The biochemical parameters such as LDH and serotonin also were measured in the supernatants of preservation solutions. RESULTS: Fresh newborn grafts were revascularized successfully at a rate of 80% (16 of 20). After 24 hours of preservation, 65% (13 of 20), 75% (15 of 20), and 85% (17 of 20) of the grafts were observed to be revascularized in LR, m-TOM, and UW solutions, respectively. After 48 hours of preservation, 60% (12 of 20), 80% (16 of 20), and 80% (16 of 20) of the grafts also were revascularized in the respective solutions (no statistic difference among the groups). The cold-preservation did not affect the neovascularization of newborn intestine until 48 hours. Histologic findings of the preserved intestine and biochemical analyses showed that UW and m-TOM solutions kept villous architectures of the preserved grafts, however, might be harmful to enterochromaffin cells. CONCLUSION: Long-time preservation of newborn intestine did not interfere with neovascularization and maturation. J Pediatr Surg 36:1805-1810.

Animals↗
PubMed2001

Real time visualization of 13N-translocation in rice under different environmental conditions using positron emitting Ttacer imaging system.

The ammonium ion is an indispensable nitrogen source for crops, especially paddy rice (Oryza sativa L. cv Nipponbare). Until now, it has been impossible to measure ammonium uptake and nitrogen movement in plants in real time. Using the new technologies of PETIS (positron emitting tracer imaging system) and PMPS (positron multi-probe system), we were able to visualize the real time translocation of nitrogen and water in rice plants. We used positron-emitting 13N-labeled ammonium (13NH4+) and 15O-water to monitor the movement. In plants cultured under normal conditions, 13NH4+ supplied to roots was taken up, and a 13N signal was detected at the discrimination center, the basal part of the shoots, within 2 minutes. This rapid translocation of (13)N was almost completely inhibited by a glutamine synthetase inhibitor, methionine sulfoximine. In general, nitrogen deficiency enhanced 13N translocation to the discrimination center. In the dark, 13N translocation to the discrimination center was suppressed to 40% of control levels, whereas 15O-water flow from the root to the discrimination center stopped completely in the dark. In abscisic acid-treated rice, 13N translocation to the discrimination center was doubled, whereas translocation to leaves decreased to 40% of control levels. Pretreatment with NO3- for 36 hours increased 13N translocation from the roots to the discrimination center to 5 times of control levels. These results suggest that ammonium assimilation (from the roots to the discrimination center) depends passively on water flow, but actively on NH4+-transporter(s) or glutamine synthetase(s).

Biological Transport↗
PubMed2001

Deletion mutants of human deoxycytidine kinase mRNA in cells resistant to antitumor cytosine nucleosides.

We studied mutational events in deoxycytidine (dCyd) kinase mRNA expression, focusing on aberrant dCyd kinase mRNA, which has been frequently observed in established cell lines resistant to antitumor dCyd nucleoside analogues such as 1-beta-D-arabinofuranosyl cytosine (Ara-C), gemcitabine (dFdC) and 2'-C-cyano-2'-deoxy-1-beta-D-arabinofuranosylcytosine (CNDAC). We describe here the expression of aberrant dCyd kinase mRNAs identified as splicing mutants. These mutants included deletions of the fifth exon in CNDAC-resistant cells (originating from HT-1080 cells), of the third exon in Ara-C-resistant cells (originating from SK-MEL-28 cells) and of the fourth exon in 2'-deoxy-2'-methylidenecytidine (DMDC)-resistant cells (originating from SK-MEL-28 cells). Various nucleoside-resistant cells originating from the same parental HT-1080 cells were established. The resulting cells expressed the same mRNA with deletion of the fifth exon, and the location of splicing was independent of the type of nucleosides used for the establishment of resistant cells. The deletion of the fifth exon in dCyd kinase seems to be a target for acquisition of resistance to antitumor cytosine nucleosides. However, distinct mutations in the dCyd kinase gene seem to be associated with acquisition of resistance to different antitumor cytosine nucleosides.

Antimetabolites, Antineoplastic↗