Biomedical subjects

T Ochi

Publications and source records attributed to T Ochi.

At least 91 records · Page 5Linked to original sources

PubMed1999

Antinociceptive properties of FR140423 mediated through spinal delta-, but not mu- and kappa-, opioid receptors.

We investigated the antinociceptive effect of FR140423, 3-(difluoromethyl)-1-(4-methoxyphenyl)-5-[4-(methylsulfinyl)phenyl] pyrazole, in the tail-pinch test in mice, and evaluated the mechanism of action using various opioid receptor antagonists. P.o. and i.t. injection of FR140423 exerted dose-dependent antinociceptive activities with ED50 values of 21 mg/kg and 3.1 microg/mouse, respectively. However, i.c.v. injection of FR140423 did not show an antinociceptive effect. The antinociceptive effects of FR140423 were completely abolished by naloxone and naltrindole but not by naloxonazine, beta-funaltrexamine and nor-binaltorphimine. FR140423 did not affect any opioid receptor binding in mouse spinal membranes at concentrations up to 100 microM in vitro. Naloxone-induced jumping and diarrhea tests for morphine-like physical dependence of FR140423 gave negative results. These results suggest that FR140423 can induce antinociception by acting on the spinal but not the supraspinal site, and that spinal delta-opioid systems indirectly play a role in the antinociception produced by FR140423 in mice.

Administration, Oral↗

PubMed1999

Distribution of gamma-tubulin in multipolar spindles and multinucleated cells induced by dimethylarsinic acid, a methylated derivative of inorganic arsenics, in Chinese hamster V79 cells.

Localization of gamma-tubulin, a well-characterized component of microtubule-organizing centers (MTOCs), was investigated because of interest in the mechanism of the induction of aberrant mitotic spindles in Chinese hamster V79 cells exposed to dimethylarsinic acid (DMAA). In control cultures, gamma-tubulin in interphase cells was located as a perinuclear dot on which the microtubules were nucleated. In metaphase cells, the location of gamma-tubulin coincided with that of the mitotic spindle poles. DMAA caused mitotic delay and aberrant spindles, such as tripolar- and quadripolar spindles, in the mitotic cells. Gamma-tubulin was co-localized with the aberrant spindles induced by DMAA. The incidence of gamma-tubulin in the mitotic cells coincided with that of the aberrant spindles and rose with an increasing concentration of DMAA. By contrast, DMAA did not influence the number and location of gamma-tubulin signals in interphase cells. These results suggest that multiple microtubule nucleation sites were induced by DMAA during transition from interphase to mitotic phase. DMAA-induced multiple signals of gamma-tubulin were integrated into one signal at the center of multinucleated cells, surrounded by multiple nuclei as the cell cycle progressed to the next interphase, suggesting the presence of a self-integration mechanism of centrosomal MTOCs during the cell cycle.

Animals↗

PubMed1999

Discordant expression of c-Ret and glial cell line-derived neurotrophic factor receptor alpha-1 mRNAs in response to motor nerve injury in neonate rats.

Adult motoneurons can survive following axotomy, whereas neonate motoneurons result in cell death. Following hypoglossal nerve axotomy in neonate rat, Glial cell line-Derived Neurotrophic Factor (GDNF) receptor alpha-1 (GFRalpha-1) mRNA expression was dramatically suppressed in the injured motoneurons, while a slight increase of c-Ret mRNA expression was observed. In adult, both GFRalpha-1 and c-Ret mRNAs increased substantially after axotomy. The present result suggests that the difference of motoneuron fate after axotomy may be partly due to the coordinate or discordant responses of GFRalpha-1 and c-Ret expression to nerve injury.

Aging↗

PubMed1999

Can intramedullary signal change on magnetic resonance imaging predict surgical outcome in cervical spondylotic myelopathy?

STUDY DESIGN: A retrospective study evaluating magnetic resonance imaging, computed tomographic myelography, and clinical parameters in patients with cervical spondylotic myelopathy. OBJECTIVES: To investigate whether magnetic resonance imaging can predict the surgical outcome in patients with cervical spondylotic myelopathy. SUMMARY OF BACKGROUND DATA: No previous studies have established whether areas of high signal intensity in T2-weighted magnetic resonance images can be a predictor of surgical outcomes. METHODS: Fifty patients with cervical spondylotic myelopathy were examined by magnetic resonance imaging and computed tomographic myelography before surgery and by delayed computed tomographic myelography after surgery. The correlation between the recovery rate and the clinical and imaging parameters was analyzed. RESULTS: The best prognostic factor was the transverse area of the spinal cord at maximum compression (correlation coefficient, R = 0.58). The presence of high signal intensity areas on T2-weighted magnetic resonance images correlated poorly with the recovery rate (R = -0.29). However, patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poor surgical results associated with muscle atrophy in the upper extremities. Postoperative delayed computed tomographic myelography showed that multisegmental areas of high signal intensity on T2-weighted magnetic resonance images probably represent cavitation in the central spinal cord. CONCLUSIONS: Patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poorer surgical results. However, the transverse area of the spinal cord at the level of maximum compression was a better prognostic indicator.

Aged↗

PubMed1999

Anti-inflammatory and analgesic effects of a novel pyrazole derivative, FR140423.

The pharmacological profile of a novel and newly discovered non-steroidal anti-inflammatory and analgesic compound, 3-(difluoromethyl)-1-(4-methoxyphenyl)-5-[4-(methylsulfinyl)phenyl]pyraz ole (FR140423), was investigated. In recombinant human cyclooxygenase enzyme assays, the inhibition of prostaglandin E2 formation by FR140423 was 150 times more selective for cyclooxygenase-2 than cyclooxygenase-1. Oral administration of FR140423 dose dependently reduced carrageenin-induced paw edema and adjuvant arthritis. These effects were two- to three-fold more potent than those of indomethacin. Unlike indomethacin, FR140423 did not induce mucosal lesions in the stomach. FR140423 showed dose-dependent anti-hyperalgesic effects in the yeast-induced hyperalgesic model. This effect was five-fold more potent than that of indomethacin. Furthermore, FR140423 increased the pain threshold in non-inflamed paws and, unlike indomethacin, it produced an analgesic effect in the tail-flick test. These analgesic effects were blocked by the mu-opioid antagonist naloxone. These results suggest that FR140423, a selective cyclooxygenase-2 inhibitor, is a potent non-steroidal anti-inflammatory drug (NSAID) without gastrointestinal side effects and is a unique compound having morphine-like analgesic effects.

Analgesics↗

PubMed1999

Expressed-sequence-tag approach to identify differentially expressed genes following peripheral nerve axotomy.

Gene expression profiles in the rat hypoglossal nucleus after axotomy were demonstrated using expressed-sequence-tag (EST) approach. To demonstrate the gene-expression profiles after axotomy, nerve-transected hypoglossal nuclei were dissected and collected from about 1000 rats, with which a cDNA library was constructed. More than 750 clones were sub-cloned and sequenced from the library. The clones which hit frequently are likely to be associated with mitochondrial respiratory chain, cytoskeletal protein and protein synthesis. One hundred three clones from among the sequenced clones were further processed for histological screening using unilateral-hypoglossal nerve-transected brain sections by in situ hybridization histochemistry. In situ hybridization study revealed that 26% of clones examined showed upregulated expression of mRNA in response to axotomy. They included genes encoding proteins associated with glucose, lipid and protein metabolism, cytoskeleton, neurotransmission and immune reaction. The present EST analysis may have an advantage in targeting genes which are associated with nerve injury with a good efficacy, as compared with other methods such as differential display and subtraction.

Animals↗

PubMed1999

Microphthalmia-associated transcription factor interacts with PU.1 and c-Fos: determination of their subcellular localization.

Marked osteopetrosis is observed only in mi/mi mutant mice although normal osteoclastgenesis is observed in other mutant mice including null mutants at the mi locus. Mutant microphthalmia-associated transcription factor (mi-MITF) has defective nuclear localization potential. We found normal MITF (+-MITF)-c-Fos and mi-MITF-c-Fos complexes in the cytoplasm by immunoblotting, and showed that PU.1 bound with both +-MITF and mi-MITF using an electrophoretic mobility shift assay. Furthermore, the nuclear localization of PU.1 and c-Fos was inhibited by over-expressed mi-MITF in WEHI-3 cells. These results indicate that mi-MITF expressing in osteoclasts specifically binds to c-Fos and PU.1 which are essential transcription factors of osteoclastgenesis and that mi-MITF blocks the nuclear localization of these other transcription factors, which may result in osteopetrosis in mi/mi mutant mice.

Animals↗

PubMed1999

Role of CDMP-1 in skeletal morphogenesis: promotion of mesenchymal cell recruitment and chondrocyte differentiation.

Cartilage provides the template for endochondral ossification and is crucial for determining the length and width of the skeleton. Transgenic mice with targeted expression of recombinant cartilage-derived morphogenetic protein-1 (CDMP-1), a member of the bone morphogenetic protein family, were created to investigate the role of CDMP-1 in skeletal formation. The mice exhibited chondrodysplasia with expanded cartilage, which consists of the enlarged hypertrophic zone and the reduced proliferating chondrocyte zone. Histologically, CDMP-1 increased the number of chondroprogenitor cells and accelerated chondrocyte differentiation to hypertrophy. Expression of CDMP-1 in the notochord inhibited vertebral body formation by blocking migration of sclerotome cells to the notochord. These results indicate that CDMP-1 antagonizes the ventralization signals from the notochord. Our study suggests a molecular mechanism by which CDMP-1 regulates the formation, growth, and differentiation of the skeletal elements.

Animals↗

PubMed1999

Maturational disturbance of chondrocytes in Cbfa1-deficient mice.

Cbfa1, a transcription factor that belongs to the runt-domain gene family, plays an essential role in osteogenesis. Cbfa1-deficient mice completely lacked both intramembranous and endochondral ossification, owing to the maturational arrest of osteoblasts, indicating that Cbfa1 has a fundamental role in osteoblast differentiation. However, Cbfa1 was also expressed in chondrocytes, and its expression was increased according to the maturation of chondrocytes. Terminal hypertrophic chondrocytes expressed Cbfa1 extensively. The significant expression of Cbfa1 in hypertrophic chondrocytes was first detected at embryonic day 13.5 (E13.5), and its expression in hypertrophic chondrocytes was most prominent at E14.5-16.5. In Cbfa1-deficient mice, whose entire skeleton was composed of cartilage, the chondrocyte differentiation was disturbed. Calcification of cartilage occurred in the restricted parts of skeletons, including tibia, fibula, radius, and ulna. Type X collagen, BMP6, and Indian hedgehog were expressed in their hypertrophic chondrocytes. However, osteopontin, bone sialoprotein, and collagenase 3 were not expressed at all, indicating that they are directly regulated by Cbfa1 in the terminal hypertrophic chondrocytes. Chondrocyte differentiation was severely disturbed in the rest of the skeleton. The expression of PTH/PTHrP receptor, Indian hedgehog, type X collagen, and BMP6 was not detected in humerus and femur, indicating that chondrocyte differentiation was blocked before prehypertrophic chondrocytes. These findings demonstrate that Cbfa1 is an important factor for chondrocyte differentiation.

Animals↗

PubMed1999

Establishment and characterization of nurse cell-like stromal cell lines from synovial tissues of patients with rheumatoid arthritis.

OBJECTIVE: To investigate the features of synovial stromal cells established from patients with rheumatoid arthritis (RA), and to define these cells as nurse cells. METHODS: Synovial nurse-like stromal cell lines (RA-SNCs) were established from patients with RA. These cell lines were examined for morphology, pseudoemperipolesis activity, cell surface markers, and cytokine production. The interaction between these RA-SNCs and a synovial tissue B cell clone was also examined. RESULTS: RA-SNCs had nurse cell activity. They spontaneously produced interleukin-6 (IL-6), IL-8, granulocyte colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor. Furthermore, they produced IL-1beta and tumor necrosis factor alpha and expressed higher levels of the other cytokines after coculture with the B cell clone. Proliferation and Ig production by the B cell clone were dependent on direct contact with RA-SNCs. CONCLUSION: These results indicate that the RA-SNCs were nurse cells. The findings suggest that RA-SNCs may play an important role in the pathogenesis of RA by producing large amounts of cytokines and maintaining infiltrating lymphocytes.

Antibodies, Monoclonal↗

PubMed1999

Suppressed severity of collagen-induced arthritis by in vivo transfection of nuclear factor kappaB decoy oligodeoxynucleotides as a gene therapy.

OBJECTIVE: In both rheumatoid arthritis and collagen-induced arthritis (CIA), the nuclear factor kappaB (NF-kappaB) transcription factor plays a pivotal role in the coordinated transactivation of many cytokines related to pathogenesis. This study investigated whether synthetic double-stranded DNA that show a high affinity for NF-kappaB could be introduced in vivo as "decoy" cis elements to bind the transcription factor and block the activation of such proinflammatory cytokine genes as interleukin-1 (IL-1) and tumor necrosis factor alpha (TNFalpha), and thus suppress the severity of joint destruction. METHODS: NF-kappaB decoy oligonucleotides (ODN) were introduced by an intraarticular injection into the bilateral hind ankle joints of CIA rats using the hemagglutinating virus of Japan (HVJ)-liposome method. Joint destruction was evaluated by histology and radiography. IL-1 and TNFalpha levels were assessed by enzyme-linked immunosorbent assay and Northern blot analysis. RESULTS: Using the HVJ-liposome method, the presence of fluorescein isothiocyanate-labeled ODN in the synovium was confirmed until 28 days after intraarticular injection. In vivo transfection of NF-kappaB decoy ODN by an intraarticular injection into CIA rats decreased the severity of hind-paw swelling. Histologic and radiographic studies showed a marked suppression of joint destruction treated by NF-kappaB decoy ODN transfection. This treatment method also suppressed the production of IL-1 and TNFalpha in the synovium of arthritic joints. CONCLUSION: The present results demonstrate that administration of NF-kappaB decoy ODN in arthritic joints of rats with CIA led to an amelioration of arthritis. These findings suggest that intraarticular transfection of NF-kappaB decoy ODN may provide a useful therapeutic approach for the treatment of inflammatory arthritis.

Animals↗

PubMed1999

Contrast-enhanced magnetic resonance imaging in a nontraumatic rabbit osteonecrosis model.

We investigated early osteonecrosis using in vivo magnetic resonance imaging in a nontraumatic rabbit model of serum-sickness osteonecrosis in which osteonecrosis was induced after two intravenous injections of horse serum with a 3-week interval. One week (group A, 17 rabbits) and 3 weeks (group B, 13 rabbits) after the second serum injection, coronal magnetic resonance images of the femur were obtained and it was removed for histological study. Some of the necrotic lesions in the diaphysis were detected on T1-weighted, T2-weighted, or fat-suppression T1-weighted images (six of 24 necrotic lesions in group A and 16 of 18 in group B), and all of the necrotic lesions in the epiphysis, metaphysis, and diaphysis were detected on T1-weighted or fat-suppression T1-weighted images enhanced with gadolinium-diethylene triamine pentaacetic acid. All focal homogeneous enhanced areas on T1-weighted or fat suppression T1-weighted images corresponded to necrotic lesions (22 of 24 necrotic lesions in group A and 18 of 18 in group B); the contours of the enhanced areas were displayed more clearly on the fat-suppression T1-weighted than on the T1-weighted images. The fat-suppression T1-weighted image enhanced with gadolinium-diethylene triamine pentaacetic acid was thus the most sensitive and specific of five kinds of magnetic resonance images for the detection of early necrotic lesions. The results suggest that this image may be useful for early diagnosis of clinical osteonecrosis and for obtaining information about the pathomechanism of osteonecrosis.

Animals↗

PubMed1999

Suppressive influences of methotrexate on the generation of CD14(+) monocyte-lineage cells from bone marrow of patients with rheumatoid arthritis.

An adequate supply of peripheral blood monocytes, granulocytes, and platelets is necessary for an optimal inflammatory process. We have previously demonstrated that the generation of CD14(+) monocyte lineage cells from the bone marrow is accelerated in patients with rheumatoid arthritis (RA). The current studies examined the influences of methotrexate (MTX), a potent disease modifying antirheumatic drug (DMARD), on the capacity of bone marrow progenitor cells to generate CD14(+) cells in patients with RA, in order to delineate its mechanism of action. CD14(-) cells purified from bone marrow specimens of 14 patients with active RA were cultured in the presence or the absence of pharmacologically attainable concentrations of MTX (0.2 microM). After incubation for 14 days, the cells were analyzed by flow cytometry for expression of CD14 and HLA-DR. The generation of CD14(+) cells from RA bone marrow CD14(-) progenitor cells was significantly suppressed by MTX. However, the expression of HLA-DR on bone marrow-derived CD14(+) cells was not significantly influenced by MTX. There was no significant difference in the effect of MTX on the generation of CD14(+) cells between patients with prednisolone and those without prednisolone. The production of IL-12 in bone marrow cell cultures was not inhibited, but was rather enhanced, by MTX, suggesting that the suppression of the generation of CD14(+) cells might not be due to the inhibition of cytokine production. The results are consistent with the hypothesis that one of the effects of DMARDs may involve the interference with monocyte differentiation in the bone marrow. Moreover, the data suggest that the generation of CD14(+) cells and the expression of HLA-DR on such marrow-derived CD14(+) cells are regulated by different mechanisms.

Adult↗

PubMed1999

Stem length and canal filling in uncemented custom-made total hip arthroplasty.

We reviewed 60 custom-made femoral components of two different lengths : 125 mm (group A) and 100 mm (group B), in order to investigate the relationship between stem length and canal filling in uncemented custom-made total hip arthroplasty. There were no statistical differences between the two groups in age, gender, height, body weight, canal flare index, or bowing angle of the femur. Postoperatively there was no statistical difference between the two groups in the proximal canal filling, but significant difference in the distal canal filling (75.5% vs 85.8% on the anteroposterior view and 76.0% vs 82.5% in the lateral view, P<0.001). The distal canal filling inversely correlated with the ratio of the proximal portion and the distal portion of the stem curvature on the lateral view (lateral curve ratio of the stem, P=0.002). We conclude that superior filling at both the proximal and the distal levels can be obtained by using 100-mm custom made components with a small lateral curve ratio.

Adult↗

PubMed1999

Association of the human NPPS gene with ossification of the posterior longitudinal ligament of the spine (OPLL).

OPLL (ossification of the posterior longitudinal ligament of the spine) is a common form of human myelopathy with a prevalence of as much as 4% in a variety of ethnic groups. To clarify the genetic factors that predispose to OPLL, we have studied ttw (tiptoe walking), a mouse model that presents ectopic ossification of the spinal ligaments similar to OPLL and have found that the ttw phenotype is caused by the nonsense mutation of the gene encoding nucleotide pyrophosphatase (NPPS), a membrane-bound glycoprotein thought to produce inorganic pyrophosphate, a major inhibitor of calcification and mineralization. To investigate a possible role of NPPS in the etiology of OPLL, we have examined its genetic variations in OPLL patients. A total of 323 OPLL patients was screened by means of polymerase chain reaction/single-strand conformation polymorphism analysis covering all the exons and their surrounding introns, plus about 1.5-kb of the promoter region. We identified ten nucleotide variations in the NPPS gene; five of the alterations caused amino-acid substitutions, and two of them were found specifically in OPLL patients. Subsequently, we performed an association study using these variations and found a significant association of an allele, viz., a deletion of T at a position 11 nucleotides upstream from the splice acceptor site of intron 20 (IVS20-11delT), with OPLL; the proportion of the individuals having this deletion was significantly higher (P = 0.0029) in OPLL patients than in controls, indicating that those who have this variation may be more susceptible to the abnormal ossification of the spinal ligaments. Thus, our study suggests that NPPS plays an important role in the etiology of human OPLL.

Aged↗

PubMed1999

A clinico-pathological study of cervical myelopathy in rheumatoid arthritis: post-mortem analysis of two cases.

Two patients who developed cervical myelopathy secondary to rheumatoid arthritis were analyzed post mortem. One patient had anterior atlanto-axial subluxation (AAS) combined with subaxial subluxation (SS), and the other had vertical subluxation (VS) combined with SS. In the patient with AAS, the posterior aspect of the spinal cord demonstrated severe constriction at the C2 segment, which arose from dynamic osseous compression by the C1 posterior arch. A histological cross-section of the spinal cord at the segment was characterized by distinct necrosis in the posterior white columns and the gray matter. In the patient with VS, the upper cervical cord and medulla oblongata showed angulation over the invaginated odontoid process, whereas no significant pathological changes were observed. At the level of SS, the spinal cord was pinched and compressed between the upper corner of the vertebral body and the lower edge of the lamina. Histologically, demyelination and gliosis were observed in the posterior and lateral white columns.

Arthritis, Rheumatoid↗

PubMed1999

Polymorphisms in the 5'-flanking region of tumor necrosis factor-alpha gene in patients with rheumatoid arthritis.

Polymorphisms in the 5'-flanking promoter/enhancer region of the tumor necrosis factor (TNF)-a gene were examined to study the genetic background of rheumatoid arthritis (RA). Four variant alleles, -1,031C/ -863A, -1,031C/-238A, -857T and -308A, were identified and examined in 387 RA patients and 575 healthy Japanese controls. The frequency of the -857T allele in RA patients was significantly higher than that in the controls. However, the HLA-DRB1 analysis in the same subjects showed that the DRB1*0405 allele, which is in linkage disequilibrium with the -857T, was more strongly associated with the disease susceptibility than the -857T allele. These results suggest that the susceptible gene to RA is more closely linked to the HLA-DRB1 locus than to the TNF-alpha locus.

5' Untranslated Regions↗

PubMed1999

Frequent loss of expression or aberrant alternative splicing of P2XM, a p53-inducible gene, in soft-tissue tumours.

We investigated expression of a human p53-inducible gene, P2XM, a member of the P2X-receptor family of ATP-gated ion channels, in 56 human primary soft-tissue tumours including 47 sarcomas and nine benign tumors. Among the 47 sarcomas examined by reverse transcription polymerase chain reaction, 12 had lost expression of this gene and 22 revealed altered splicing patterns; among the nine benign tumours, four showed no expression of P2XM and three revealed aberrant splicing patterns involving transmembrane domains M1 and/or M2. As the aberrant transcripts lacked either or both of those domains, the protein products probably lacked normal function. We also looked for p53 mutations and mdm2 overexpression in the same panel of tumours and found them in 13 tumours, all but three of which had shown altered expression of P2XM. However, 31 (72%) of the 43 tumours that carried wild-type p53 without mdm2 overexpression had revealed aberrant P2XM expression. Our results suggest that disorder of P2XM expression may play a crucial role in the genesis of benign and malignant tumours in soft tissues, and that one or more genetic factors other than p53 or mdm2 contribute significantly to aberrant P2XM expression.

Amino Acid Sequence↗