Biomedical subjects

A Uchida

Publications and source records attributed to A Uchida.

At least 55 records · Page 3Linked to original sources

PubMed2001

Uptake of Au(III) Ions by Aluminum Hydroxide and Their Spontaneous Reduction to Elemental Gold (Au(0)).

The behavior of AuCl(4)(-) ions during the formation of aluminum hydroxide at pH 6 was examined. With an increase in NaCl concentration, the content of gold taken up by aluminum hydroxide decreased, suggesting that chloro-hydroxy complexes of Au(III) ion were taken up due to the formation of Al-O-Au bonds. It was found unexpectedly that the Au(III) ions taken up were spontaneously reduced to elemental gold without addition of a specific reducing reagent and then colloidal gold particles were formed. The mechanisms for the uptake of Au(III) ions by aluminum hydroxide and for their spontaneous reduction are discussed. Copyright 2001 Academic Press.

Journal Article↗

PubMed2001

Nerve growth factor signaling of p75 induces differentiation and ceramide-mediated apoptosis in Schwann cells cultured from degenerating nerves.

In peripheral nerve regeneration or remyelination, immature Schwann cells expressing p75(NTR) play cardinal roles in the support and regeneration of axons (Griffin JW, Hoffman PN. Peripheral Neuropathy 361-376, 1993). Only one of four to six Schwann cells participate in remyelination of damaged or regenerating axons. The rest of the cells, or supernumerary Schwann cells, show severe atrophy and gradually decrease in number, reestablishing a 1:1 axon-Schwann cell relationship (Said G, Duckett S. Acta Neuropathol (Berl) 53:173-179, 1981). Recent reports demonstrated that severely atrophied supernumerary Schwann cells are eliminated by apoptosis during axonal regeneration or remyelination (Hirata H, Hibasami H. Apoptosis 3:353-360, 1998; Berciano MT, Calle E. Acta Neuropathol (Berl) 95:269-279, 1998). The mechanism to induce selective death of supernumerary Schwann cells without causing any damage to axon-associated Schwann cells or axons remains to be determined. In this article, we report that p75(NTR), the low-affinity receptor for all members of neurotrophins, signals both cell differentiation and apoptosis through intracellular ceramide elevation. The final response is dependent on the intracellular ceramide level and Schwann cells modulate their response by changing expression level of p75(NTR). This effect was selective for nerve growth factor (NGF). Taken together, the present study suggests that NGF contributes both to phenotypic regulation and to elimination of the dedifferentiated Schwann cells, while supporting survival or regeneration of certain types of axons during peripheral nerve repair or regeneration.

Animals↗

PubMed2001

Infection of synoviocytes with HTLV-I induces telomerase activity.

To investigate the mechanism of synovial hyperplasia by human T-lymphotropic virus type I (HTLV-I) infection, the enzymatic activity of telomerase and expression of telomerase-related factors in HTLV-I infected synoviocytes were examined. Cultured synoviocytes obtained from four patients with osteoarthritis (OA) and four with traumatic joint disease (TJD) were infected by HTLV-I. Telomerase activity was detected by telomeric repeat amplification protocol (TRAP) assay. Expression of telomerase-related mRNAs such as telomerase reverse transcriptase (hTERT), telomerase RNA component (hTERC), and telomeric repeat binding factor 2 (TRF2) were also examined. Telomerase activity was detected in all HTLV-I-infected synoviocytes but not in uninfected synoviocytes. A remarkable induction of hTERT mRNA was observed in four of eight HTLV-I-infected synoviocytes, whereas expressions of hTERC, TRF2, and TEP-1 mRNAs were not changed. Our results clearly demonstrate that HTLV-I upregulates telomerase activity in synoviocytes probably via upregulation of hTERT activity. These findings suggest that telomerase activation in synoviocytes has an important role in upregulated proliferative activity of HAAP synoviocytes.

Carrier Proteins↗

PubMed2001

New evaluation method using preoperative magnetic resonance imaging for cervical spondylotic myelopathy.

A new method based on the score of preoperative magnetic resonance images (MRI) was devised to evaluate cervical spondylotic myelopathy and predict the results of cervical laminoplasty. On T1- and T2-weighted sagittal MRI, the intervertebral disc spaces at each level from the axis to the first thoracic spine were examined as to whether the anterior or posterior subarachnoid space would be maintained or not, and for the presence or absence of spinal cord deformity. The data were divided into six grades and rated, and the total score for all sites was regarded as the preoperative MRI cumulative score. In conclusion, our method was highly reliable and useful for a preoperative evaluation and prediction of results after cervical laminoplasty for cervical spondylotic myelopathy.

Adult↗

PubMed2001

Limb-lengthening and angular correction for dysplasia epiphysealis hemimelica.

We report a patient with severe varus deformity and tibial shortening caused by dysplasia epiphysealis hemimelica (DEH), a rare skeletal developmental disorder characterized by an osteocartilaginous tumor arising from an epiphysis in young children. Limb lengthening and angular correction was performed successfully, with an excellent result without abnormal bone growth.

Bone Lengthening↗

PubMed2001

In vivo suicide gene therapy model using a newly discovered prostate-specific membrane antigen promoter/enhancer: a potential alternative approach to androgen deprivation therapy.

Prostate-specific membrane antigen (PSMA) is a type-2 membrane protein expressed in the prostate, and it is highly expressed in metastatic or poorly differentiated adenocarcinomas. Moreover, PSMA expression is upregulated by androgen deprivation. These advantages make PSMA a useful target for prostate cancer therapy, especially in combination with conventional hormonal treatment. We recently reported that a prostate-specific enhancer is present in the third intron of the PSMA gene. In this study, we have further analyzed the activity of PSMA promoter/enhancer in prostate cancer cells and cells of other tissue origins (breast cancer MCF-7, lung cancer H157, and colorectal cancer HCT8 cells), and we have examined whether this construct could be used for efficient expression of the suicide gene, cytosine deaminase (CD), in vivo. The PSMA promoter/enhancer expressed the luciferase reporter gene in the prostate cancer lines LNCaP and C4-2, with 8- to 20-fold higher expression than the simian virus 40 promoter/enhancer, although it was inactive in the other cell lines. This construct efficiently drove the suicide gene CD, sensitizing C4-2 cells to 5-fluorocytosine (5-FC) with the inhibitory concentration (IC(50)) <300 micromol/L in vitro. Athymic male nude mice bearing the transfected C4-2 cells were treated with intraperitoneal injections of either 5-FC (600 mg/kg) twice a day or saline solution for 3 weeks. C4-2 cell tumors were eliminated by 5-FC when they were expressing our therapeutic construct carrying CD under the regulatory control of the PSMA promoter/enhancer. Our results show the in vivo utility of the PSMA promoter/enhancer in a gene therapy situation targeting prostate cancer.

Adenocarcinoma↗

PubMed2001

Suppression of CYP3A2 mRNA expression in the warfarin-resistant roof rat, Rattus rattus: possible involvement of cytochrome P450 in the warfarin resistance mechanism.

1. The continual use of warfarin as a rodenticide has caused the development of populations of warfarin-resistant roof rat. To study the biochemical mechanism of warfarin resistance, the mRNA expression levels of the major P450 forms in the warfarin-resistant and -susceptible roof rat liver following exposure to warfarin were quantified by competitive RT-PCR. 2. The constitutive levels of CYP2C11 and CYP3A2 mRNAs in the warfarin-resistant and -susceptible roof rat were extremely low compared with those in the STD rat. In response to warfarin administration, the CYP3A2 mRNA level in the warfarin-susceptible rat increased to about 3-fold of that before the treatment, whereas in the warfarin-resistant roof rat, CYP3A2 mRNA remained at a low level. 3. The present results suggest the possibility that reduced synthesis of CYP3A2 mRNA is involved in the warfarin-resistant mechanism in the roof rat.

Animals↗

PubMed2001

Water-soluble chlorophyll protein in Brassicaceae plants is a stress-induced chlorophyll-binding protein.

Two kinds of water-soluble chlorophyll (Chl) proteins (WSCPs) have been found, e.g., a WSCP from Chenopodium, Atriplex, Polygonum, and Amaranthus species (class I) and that from Brassica, Raphanus, and Lepidium species (class II). Classes I and II WSCPs differ mainly in their photoconvertiblity. Class I WSCPs show a light-induced absorption change, whereas Class II WSCPs do not. The molecular and functional properties of Class I WSCP are largely uncertain. On the other hand, recent studies on the adaptation of plants to osmotic stress revealed the participation of drought-stress induced proteins with molecular masses of 20-22 kDa possessing a sequence similarity with class II WSCPs. This mini review focuses on the molecular signature of class II WSCPs. The physiological function of class II WSCPs has not been clarified either, but, their water-solubility, low Chl content, and stress-inducibility suggested little contribution to photosynthesis. Several molecular properties predicting its physiological role are as follows. The WSCP tetramer, may have only one or no Chl molecules in each subunit. All WSCPs possess a motif for Künitz-type proteinase inhibitor family in their sequence. WSCP is induced by drought- and heat-stresses suggesting its protective role during stress conditions. Monomeric recombinant apo-WSCP is able to remove Chls from the thylakoid membrane in aqueous solution and form into a tetramer. Brassica-WSCP contains a signal sequence targeted to endoplasmic reticulum. The highly conserved, C-terminal region is missing in the mature WSCP. Possible functions of class II WSCPs in plant tissues are discussed.

Adaptation, Physiological↗

PubMed2001

Pyrobaculum oguniense sp. nov., a novel facultatively aerobic and hyperthermophilic archaeon growing at up to 97 degrees C.

A novel hyperthermophilic, heterotrophic, rod-shaped archaeon was isolated from a terrestrial hot spring at Oguni-cho, Kumamoto Prefecture, Japan. The new isolate, strain TE7T, grew under aerobic, microaerobic and anaerobic conditions. Isolate TE7T grew optimally at 90-94 degrees C and pH 7.0-7.5 (adjusted at 25 degrees C) under atmospheric air with vigorous shaking. Strain TE7T cells were motile rods 2-10 microm in length and covered with a surface-layer lattice. Cell yields at 90 degrees C under aerobic conditions were twice that under anaerobic conditions. Under aerobic conditions, growth was inhibited by elemental sulfur, but thiosulfate stimulated growth. Under anaerobic conditions, no growth was observed in the presence of nitrate and nitrite, but elemental sulfur, thiosulfate, L-cystine and oxidized glutathione stimulated growth. The 16S rDNA sequence of TE7T exhibited a close relationship to the sequences of Pyrobaculum aerophilum and Thermoproteus neutrophilus, which belong to the cluster of the genus Pyrobaculum. DNA-DNA hybridization analysis showed a low level of DNA similarity between TE7T and previously described Pyrobaculum species. As TE7T is phenotypically and phylogenetically different from the other members of this genus, it is described as a new species named Pyrobaculum oguniense (type strain TE7T = JCM 10595T = DSM 13380T).

Aerobiosis↗

PubMed2001

Amino acid sequence of a trypsin inhibitor from a Spirometra (Spirometra erinaceieuropaei).

A trypsin inhibitor that is highly homologous with bovine pancreatic trypsin inhibitor (BPTI) was co-purified along with RNase from Spirometra (Spirometra erinaceieuropaei). The amino acid sequence of this inhibitor (SETI) and the nucleotide sequence of the cDNA encoding this protein were determined by protein chemistry and gene technology. SETI contains 68 amino acid residues and has a molecular mass of 7,798 Da. SETI has 31 amino acid residues that are identical with BPTI's sequence, including 6 half-cystine and 5 aromatic amino acid residues. The active site Lys residue in BPTI is replaced by an Arg residue in SETI. SETI is an effective inhibitor of trypsin and moderately inhibits a-chymotrypsin, but less inhibits elastase or subtilisin. SETI was expressed by E. coli containing a PelB vector carrying the SETI encoding cDNA; an expression yield of 0.68 mg/l was obtained. The phylogenetic relationship of SETI and the other BPTI-like trypsin inhibitors was analyzed using most likelihood inference methods.

Amino Acid Sequence↗

PubMed2001

[Strain-, sex- and species-related differences of acetohexamide reductase and 20 beta-hydroxysteroid dehydrogenase activities in liver microsomes of experimental animals].

We examined physiological and genetic factors affecting acetohexamide reductase (AHR) and 20 beta-hydroxysteroid dehydrogenase (20 beta-HSD) activities in liver microsomes of experimental animals. Pronounced strain-related differences were found in both activities of AHR and 20 beta-HSD present in liver microsomes of male rats. Among rat strains tested in this study, even though a Wistar-Imamichi (WIM) rat strain was taken to lack AHR activity, it exhibited a significant 20 beta-HSD activity. These findings appeared to be in conflict with our conclusion reported so far, which AHR and 20 beta-HSD present in liver microsomes of male rats are identical enzymes. Thus the reason for this discrepancy was discussed. Furthermore, AHR and 20 beta-HSD activities were little or not observed in liver microsomes of female rats or male experimental animals other than the rat, indicating the existence of sex- and species-related differences in these two enzyme activities.

20-Hydroxysteroid Dehydrogenases↗

PubMed2001

[Anti-GQ1b IgG-negative case of overlapping Fisher's and Gullain-Barré syndromes after Campylobacter jejuni (PEN 19) enteritis].

We described a 70-year-old woman with overlapping Fisher's syndrome (FS) and Guillain-Barré syndrome (GBS), from whom Campylobacter jejuni had been isolated. In typical FS as well as GBS with ophthalmoplegia and acute ophthalmoparesis without ataxia, serum anti-GQ1b IgG antibody often is detected and ophthalmoplegia is characterized by the predominant abducens palsy. This patient, however, showed marked oculomotor nerve disturbance. Serum anti-GQ1b IgG antibody was negative and IgG antibodies against GM1, GM1b, and GD1a were strongly positive. Although FS and overlap of FS/GBS have been reported to be associated with PEN2 of C. jejuni, the isolate from our case belonged to PEN 19. C. jejuni serotype may be associated with clinical manifestations and anti-ganglioside antibody species.

Aged↗

PubMed2000

Prostate-specific suicide gene therapy using the prostate-specific membrane antigen promoter and enhancer.

BACKGROUND: Prostate-specific membrane antigen (PSMA) is abundantly expressed in virtually 100% of prostate cancers and metastases. In addition, unlike prostate-specific antigen (PSA), PSMA is upregulated under conditions of androgen deprivation. Therefore, PSMA is an attractive therapeutic target for advanced prostate cancer. Recently, both the promoter and the enhancer driving prostate-specific expression of the PSMA gene were cloned. We describe here our analysis of the PSMA enhancer for the most active region(s) and present a way of using the enhancer in combination with the E. coli cytosine deaminase gene for suicide-driven gene therapy that converts the nontoxic prodrug 5-fluorocytosine (5-FC) into the cytotoxic drug 5-fluorouracil (5-FU) in prostate cancer cells. METHODS: Deletion constructs of the full-length PSMA enhancer were subcloned into a luciferase reporter vector containing either the PSMA or SV-40 promoter. The most active portion of the enhancer was then determined via luciferase activity in the C4-2 cell line. We then replaced the luciferase gene with the E. coli cytosine deaminase gene in the subclone that showed the most luciferase activity. The specificity of this technique was examined in vitro, using the prostate cancer cell line LNCaP, its androgen-independent derivative C4-2, and a number of nonprostatic cell lines. The toxicity of 5-FC and 5-FU on transiently transfected cell lines was then compared. RESULTS: The enhancer region originally isolated from the PSMA gene was approximately 2 kb. Deletion constructs revealed that at least two distinct regions seem to contribute to expression of the gene in prostate cancer cells, and therefore the best construct for prostate-specific expression was determined to be 1, 648 bp long. The IC(50) of 5-FC was similar in all cell lines tested (>10 mM). However, transfection with the 1648 nt PSMA enhancer and the PSMA promoter to drive the cytosine deaminase gene enhanced toxicity in a dose-dependent manner more than 50-fold, while cells that did not express the PSMA gene were not significantly sensitized by transfection. CONCLUSIONS: Suicide gene therapy using the PSMA enhancer may be of benefit to patients who have undergone androgen ablation therapy and are suffering a relapse of disease.

Antigens, Surface↗

PubMed2000

Induction of c-Src in human blood monocytes by anti-CD98/FRP-1 mAb in an Sp1-dependent fashion.

Freshly isolated human blood monocytes expressed neither c-src mRNA nor c-Src. However, when monocytes were incubated with anti-CD98 heavy chain (HC) mAb, expression of c-src mRNA, c-Src, and activated c-Src was induced. Many binding sites for the ubiquitous transcription factor Sp1 were identified in the promoter region of the c-src gene. Surprisingly, Sp1 and Sp1 mRNA were not found in monocytes that were freshly isolated or incubated with control antibody. Stimulation with anti-CD98HC mAb also resulted in the expression of Sp1 and its translocation to the nucleus. Herbimycin A, genistein, manumycin A, PD-98059, SB203580, and HBJ127 suppressed CD98HC-mediated c-src and Sp1 mRNA induction. On the contrary, H-7, Wortmannin, HA1077, and Y-27632 showed no effect on c-Src and Sp1 induction. Furthermore, anti-CD98HC mAb induced activation of tyrosine kinases and ERK kinases. These findings suggest that the tyrosine kinase(s)-Ras-MAPK-Sp1 pathway(s) is involved in CD98HC-mediated induction of c-Src in human blood monocytes.

Antibodies, Monoclonal↗

PubMed2000

Further studies on 20beta-hydroxysteroid dehydrogenase with carbonyl reductase-like activity present in liver microsomes of male rats.

Further characterizations of 20beta-hydroxysteroid dehydrogenase (20beta-HSD) present in liver microsomes of male rats were examined. A significant relationship was observed between 20beta-HSD and acetohexamide reductase (AHR) activities in liver microsomes of male rats. The hepatic microsomal 20beta-HSD and AHR preferentially required NADPH as a cofactor. When NADPH was replaced by NADH, NADP or NAD at the same concentration, these reductase activities were little detected. The hepatic microsomal 20beta-HSD and AHR activities in streptozotocin-induced diabetic rats were much lower than those in the corresponding controls. The hepatic microsomal 20beta-HSD and AHR activities appeared as one main peak, respectively, on DEAE-Sephacel column chromatography, and the peak of 20beta-HSD activity was in good agreement with that of AHR activity. Based on these results, we conclude that 20beta-HSD present in liver microsomes of male rats functions as AHR, and exhibits a carbonyl reductase-like activity.

Alcohol Oxidoreductases↗

PubMed2000

Repair of nerve gap with the elongation of Wallerian degenerated nerve by tissue expansion.

We have found previously that expansion of the Wallerian degenerated nerve was accompanied by accelerated Schwann cell proliferation. In this study, we investigated the usefulness of the elongation of Wallerian degenerated nerve for the repair of short nerve gap. Male Wistar rats were used. After the left sciatic nerve was transected the rats were divided into 4 groups. In the control group, nerve coaptation was not performed. In group 1, tensionless coaptation was performed immediately. In group 2, delayed tensionless coaptation was performed with the elongation of Wallerian degenerated nerve. In group 3, coaptation was performed immediately with autologous interposition nerve graft. The ideal tensionless nerve repair of group 1 was considered to produce the best result. Rats in group 2 showed functional recovery as good as rats in group 1. On histologic assessment, in group 2, a fibrous capsule that was very rich in vascularity was formed around the tissue expander. After 14 weeks, the capsule was diminished markedly in size, but the vascularity was rich around the sciatic nerve. We think that the excellent functional recovery seen in group 2 can be attributed to the increased activity of Schwann cell proliferation and increased vascularity.

Animals↗

PubMed2000

Prenatal MRI in a fetus with a giant neck hemangioma: a case report.

We report a fetus with a giant neck hemangioma which was examined by MRI in utero. The initial diagnosis was made by ultrasonography. The sonolucent aspect of the mass, together with the presence of pulsating Doppler flow signals, was highly suggestive of a fetal hemangioma. In late pregnancy, fetal MRI revealed the location, size and characteristics of the neck tumor. Following prenatal corticosteroid treatment and premature delivery of the pregnancy due to fetal cardiac failure, the newborn received angiography and coil embolization of the tumor vessels. Despite vigorous treatments, the newborn died 12 h after birth. Evaluation of a fetal neck hemangioma by MRI is recommended late in pregnancy for precise information on the tumor and adjacent organs since the image is valuable for planning optimal perinatal treatment.

Adult↗

PubMed2000

Ability of osteoclast formation from peripheral monocytes using anti-fusion regulatory protein-1/CD98/4F2 monoclonal antibodies in patients with osteoporosis.

We investigated the difference in osteoclast formation between patients with osteoporosis and two healthy control groups by inducing it from peripheral blood monocytes with use of anti-fusion regulatory protein- monoclonal antibody. The group of patients with osteoporosis consisted of 35 women and excluded secondary osteoporosis, and the control groups consisted of 12 young healthy volunteers (control I) or 10 individuals age-matched to the patients with osteoporosis (control II). Osteoclast formation declined with age between the two control groups, but this decline was not significant. Fusion rate and the mean number of nuclei in osteoclasts were significantly less in the patients with osteoporosis than in the young or age-matched controls. It was clearly demonstrated that the ability of monocytes to fuse declines significantly in patients with osteoporosis.

Adult↗