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Biomedical subjects

Y Yoshihara

Publications and source records attributed to Y Yoshihara.

At least 55 records · Page 3Linked to original sources
PubMed1997

Mice lacking the vitamin D receptor exhibit impaired bone formation, uterine hypoplasia and growth retardation after weaning.

1 alpha,25-Dihydroxyvitamin D3[1 alpha,25(OH)2D3], an active form of vitamin D, has roles in many biological phenomena such as calcium homeostasis and bone formation, which are thought to be mediated by the 1 alpha,25(OH)2D3 receptor (VDR), a member of the nuclear hormone receptor superfamily. However, the molecular basis for the actions of 1 alpha,25(OH)2D3 in bone formation, its role during development and VDR genetic polymorphisms for predicting bone mineral density are uncertain. To investigate the functional role of VDR, we generated mice deficient in VDR by gene targeting. We report here that in VDR null mutant mice, no defects in development and growth were observed before weaning, irrespective of reduced expression of vitamin D target genes. After weaning, however, mutants failed to thrive, with appearance of alopoecia, hypocalcaemia and infertility, and bone formation was severely impaired as a typical feature of vitamin D-dependent rickets type II (refs 8, 9). Unlike humans with this disease, most of the null mutant mice died within 15 weeks after birth, and uterine hypoplasia with impaired folliculogenesis was found in female reproductive organs. These defects, such as alopoecia and uterine hypoplasia, were not observed in vitamin D-deficient animals. The findings establish a critical role for VDR in growth, bone formation and female reproduction in the post-weaning stage.

Alopecia↗
PubMed1997

Synovial fluid concentrations of the C-propeptide of type II collagen correlate with body mass index in primary knee osteoarthritis.

OBJECTIVE: To explore in a cross sectional study in patients with primary knee osteoarthritis (OA) the relations between body mass index (BMI), disease stage, and the concentrations of a putative joint fluid marker of type II collagen synthesis, procollagen II C-propeptide. PATIENTS AND METHODS: The study included 142 patients with knee OA (median age 68, median BMI 24.1). OA was staged radiologically. The concentrations in synovial fluid of procollagen II C-propeptide were measured by a sandwich enzyme immunoassay. RESULTS: Joint fluid concentrations of procollagen II C-propeptide were increased in knees with OA (median 3.7 ng/ml), compared with published reference values for knees in healthy adult volunteers (median 1.3 ng/ml). The concentrations of procollagen II C-propeptide were independently related to both OA stage and BMI (r = 0.343, p < 0.0001 and r, = 0.253, p = 0.002, respectively). CONCLUSIONS: Joint fluid concentrations of this putative marker of collagen II synthesis are high in early and mid-stage OA, but decrease in end stage disease. In addition and for the first time it was shown that the concentrations in synovial fluid of procollagen II C-propeptide increase with increasing BMI in primary knee OA. The increased joint fluid values of this marker in patients with primary knee OA and a high BMI, may reflect increased rates of collagen synthesis in their joint cartilage and could relate to the previously shown increased risk for disease progression in such patients.

Adult↗
PubMed1997

A procedure for in situ hybridization combined with retrograde labeling of neurons: application to the study of cell adhesion molecule expression in Dil-labeled rat pyramidal neurons.

We have devised a simple method that combines retrograde labeling of projecting neurons and in situ hybridization histochemistry to examine mRNA expression in the retrogradely labeled neurons. First, projecting neurons were retrogradely labeled in vivo by injection of the lipophilic neuronal tracer Dil. The fluorescence of the labeled neurons in the brain slices was photoconverted into stable DAB precipitate by green light illumination. The slices were cut into thinner sections and processed for detection of specific mRNA by in situ hybridization. Using this highly sensitive method, we demonstrate here that the corticospinal tract neurons in newborn rats express mRNA for the cell adhesion molecule L1. TAG-1 mRNA was not detected in these neurons. Therefore, the present method provides an important tool to study the molecular expression of projection neurons during the development of neuronal circuitry.

Affinity Labels↗
PubMed1997

[Responses to surgical stress in blood coagulation and fibrinolysis, platelet counts and thromboxane B2 after esophageal cancer operation].

Studies on responses to surgical stress in blood coagulation and fibrinolysis, platelet counts and thromboxane B2 (TXB2) were carried out with 18 esophageal cancer patients who had undergone radical esophagectomy through right thoracotomy and reconstruction with gastric tube. Plasma levels were measured for the following for coagulation assessment: thrombin.antithrombin III complex (TAT), soluble fibrin monomer complex(SFMC), fibrinogen, antithrombin III, protein C and thrombomodulin. Selected fibrinolytic markers are: tissue plasminogen activator.plasminogen activator inhibitor 1 complex (tPA.PAI1C), plasminogen, alpha 2 plasmin inhibitor, plasmin. alpha 2 plasmin inhibitor complex(PIC), FDP and D-dimer. Peripheral venous blood samples were taken from the patients before the operation, immediately after the operation and on each of the first, second, third, seventh and fourteenth day after the operation. It was observed that TAT, SFMC, tPA.PAI-1C and TXB2 were remarkably altered immediately after the operation. This indicates that the major surgical stress significantly activated coagulation, fibrinolysis and platelets. Higher plasma levels of TAT compared to the pre-operation level was recorded for two weeks after the operation. Furthermore, in four cases, SFMC became positive during three to seven days after operation. These facts indicate that the activation of coagulation persisted during the days after operation. PIC began to increase from the 2nd to 3rd days after operation, reaching the maximum on the 7th day. Biphasic changes which peaked twice on the 1st and 7th days after operation were shown in plasma levels of FDP and D-dimer. These results indicate that the activation of fibrinolysis also persisted during the days after operation. The activation of coagulation and fibrinolysis may persist at least for two weeks after major surgical operation. Careful observation for the states of these systems was thought to be needed during the post-operative days, and the molecular markers could be useful to assess subclinical changes of these systems.

Adult↗
PubMed1997

[Levels of matrix metalloproteinase-3 and urokinase-type plasminogen activator in knee synovial fluids from patients with rheumatoid arthritis and osteoarthritis].

The objective of this study is to determine the levels of matrix metalloproteinase-3 (MMP-3) and urokinase-type plasminogen activator (uPA) in knee synovial fluids from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Knee synovial fluids were collected from patients with RA and OA. Concentrations of MMP-3 were determined by enzyme immunoassay using a pair of monoclonal antibodies against human proMMP-3, and activities of uPA were measured by immunocapture assay using a polyclonal antiserum against human uPA. The median concentration of MMP-3 in synovial fluids was 97.5 +/- 82.6 micrograms/ml (range 1.06-336 micrograms/ml) for RA group and 20.5 +/- 11.3 micrograms/ml (range 6.19-42.8 micrograms/ml) for OA group. Levels of MMP-3 were significantly higher in RA group than in OA group. The median activity of uPA in synovial fluids was 0.053 +/- 0.052 i.u./ml (range 0.003-0.187 i.u./ml) for RA group and 0.072 +/- 0.059 i.u./ml (range 0.006-0.169 i.u./ml) for OA group. No significant difference of uPA activity was observed between RA and OA group. Significant correlation of the levels of MMP-3 with those of uPA was observed in RA group, however not in OA group. The increased levels of MMP-3 in synovial fluids in RA group may reflect an elevated matrix degrading activity due to joint inflammation. The significant correlation of MMP-3 with uPA in RA group suggests that MMP-3 could degrade cartilage matrix more actively in conjunction with PA-plasmin system than MMP-3 alone.

Aged↗
PubMed1996

Enhancement of SPARC (osteonectin) synthesis in arthritic cartilage. Increased levels in synovial fluids from patients with rheumatoid arthritis and regulation by growth factors and cytokines in chondrocyte cultures.

OBJECTIVE: To investigate the roles of SPARC (secreted protein, acidic and rich in cysteine) (osteonectin) in arthritis, using cartilage and synovium specimens and synovial fluids (SF) from patients with rheumatoid arthritis (RA) or osteoarthritis (OA), and to examine the effects of cytokines, growth factors, and hormones on SPARC synthesis by chondrocytes in culture. METHODS: SPARC in cartilage and synovium was immunostained with monoclonal antibodies. SPARC synthesis by cultured chondrocytes was measured by Northern blot analysis, immunoblotting, and sandwich enzyme-linked immunosorbent assay. RESULTS: SPARC was identified in numerous chondrocytes in the superficial and middle zones and in regenerating chondrocytes of RA and OA joints, whereas such staining was absent in these zones of normal cartilage, except for weak signals from a few chondrocytes in the deep zone. In addition, SPARC synthesis was enhanced in synovial cells of RA and OA joints. The average SPARC level in SF was 10-fold higher in the RA than in the OA population. In rabbit articular chondrocyte cultures, administration of transforming growth factor beta 1 (TGF beta 1) and bone morphogenetic protein 2 increased SPARC levels at 24-48 hours, whereas interleukin-lbeta (IL-1 beta), IL-1 alpha, tumor necrosis factor alpha, lipopolysaccharide, phorbol myristate acetate, basic fibroblast growth factor, and dexamethasone decreased SPARC levels at 24-72 hours. TGF beta increased SPARC messenger RNA (mRNA) levels at 24 hours, whereas IL-1 beta caused a marked decrease in SPARC mRNA levels at 24 hours. Furthermore, IL-1 decreased the glycosylation of SPARC. CONCLUSION: These findings suggest that various growth factors and cytokines, including TGF beta 1 and IL-1 beta, regulate the production of SPARC by chondrocytes at pre- and posttranslational levels, and that SPARC synthesis is markedly enhanced in arthritic joints.

Adult↗
PubMed1996

Acute disseminated encephalomyelitis associated with Mycoplasma pneumoniae infection.

An 8 year old girl with acute disseminated encephalomyelitis (ADEM) is described. Elevated serum antibody titers suggested recent Mycoplasma pneumoniae infection. T2-weighted image of magnetic resonance imaging (MRI) disclosed multiple lesions of high signal intensity in bilateral basal ganglia and thalami as well as in the white matter. Postcontrast T1-weighted image revealed an enhanced lesion in the deep white matter. She showed rapid clinical improvement in response to corticosteroid therapy. The lesions had disappeared completely on MRI performed 10 weeks after the onset. ADEM is believed to be a demyelinating disorder of probable autoimmune etiology. MRI findings in this case may support the hypothesis that the primary pathological event is vascular injury and demyelination occurs only as a secondary phenomenon.

Basal Ganglia↗
PubMed1996

Procollagen II C-propeptide in joint fluid: changes in concentration with age, time after knee injury, and osteoarthritis.

OBJECTIVE: To determine in a cross sectional study the concentrations in joint fluid of the C-propeptide of collagen II (pCol II-C) in patients with knee injury and developing osteoarthritis (OA). METHODS: Synovial fluid (SF) samples were collected from knees of healthy volunteers, from patients with injury to the knee causing lesions of the anterior cruciate ligament and/or menisci, and from patients with posttraumatic or primary OA. Concentrations of pCol II-C were determined by enzyme immunoassay with a polyclonal antiserum against the bovine propeptide. RESULTS: The median concentration of pCol II-C in joint fluid in the reference group was 1.3 ng/ml (range 0.1-5.7 ng/ml). Median concentrations of pCol II-C in joint fluid were increased 2-4-fold in all 3 study groups over that in the reference group. Very high concentrations of propeptide were noted in samples from patients younger than about 18 years. Propeptide concentrations were increased after knee injury, with a suggested peak at about 1-4 years evident for patients with cruciate ligament injury. pCol II-C levels were increased at all stages of OA development, except in the most advanced phases. CONCLUSION: The increased levels of pCol II-C in SF may reflect an increased rate of synthesis of collagen II in the joint cartilage of patients with knee injury and developing OA. The increase reaches a maximum well before radiographic changes indicative of OA are apparent, and occurs during a disease phase characterized by signs of increased degradation of collagen II, aggrecan, and other matrix components. Further studies of markers of matrix metabolism of cartilage, bone, and other joint tissues in human and animal models of OA may aid in the identification of process markers, individuals at risk, and new therapeutic targets.

Adolescent↗
PubMed1996

[Levels of chondroitin 4-sulfate, chondroitin 6-sulfate and carboxy-terminal type II procollagen peptide in knee synovial fluid after injury to the anterior cruciate ligament].

Changes in the metabolism of articular cartilage associated with injury to the anterior cruciate ligament (ACL) is known to be one of the important factors for the progression to secondary osteoarthritis. To investigate the efficacy of biochemical markers for monitoring the cartilage metabolism after injury to ACL, we measured the levels of chondroitin 4-sulfate (C-4S), chondroitin 6-sulfate (C-6S) and carboxy-terminal type II procollagen peptide (pCOL II-C) in knee synovial fluid (SF) from the patients with ACL rupture and compared with those in knee osteoarthritis (OA). Within 10 days after ACL rupture, levels of C-6S and C-4S in SF were significantly higher than those in early stage of OA. Both levels decreased gradually and became to the same levels as those in early stage of OA at 30 days after the injury. In contrast, pCOL II-C levels in SF just after the injury were observed to be lower than those in early stage of OA. Then they increased gradually to the levels of those in early stage of OA at 30 days after the injury. High levels of C-6S and C-4S in SF just after ACL rupture seemed to reflect the increased release of matrix fragments caused by cartilage destruction associated with the injury. pCOL II-C levels in SF seemed to reflect the repairing process that increased slowly after the cartilage destruction. Measurement of these cartilage derived macromolecules in SF could be useful tools for monitoring the metabolism in articular cartilage after injury.

Adult↗
PubMed1995

Increased levels of stromelysin-1 and tissue inhibitor of metalloproteinases-1 in sera from patients with rheumatoid arthritis.

OBJECTIVE: To evaluate the efficacy of stromelysin-1 (matrix metalloproteinase-3 [MMP-3]) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in serum as markers for joint inflammation in rheumatoid arthritis (RA). METHODS: Levels of both macromolecules in sera from 97 healthy controls, 109 patients with RA, and 47 patients with osteoarthritis (OA) were measured by respective 1-step sandwich enzyme immunoassays. In the patients with RA, serum levels of MMP-3 and TIMP-1 were investigated in relation to laboratory and clinical measures of disease activity. In addition, the relationships between serum and synovial fluid (SF) levels in paired samples from individual patients were examined. RESULTS: Serum levels of both MMP-3 and TIMP-1 in RA patients were significantly higher than those in OA patients and in healthy controls (P < 0.001), and were shown to correlate with traditional systemic markers of inflammation including the erythrocyte sedimentation rate and C-reactive protein level, and with the Lansbury articular index. In addition, it was noted that serum levels of MMP-3 correlated with the corresponding values in paired SF samples obtained concurrently from patients with RA (rs = 0.588, P < 0.001), while such correlations were not found for TIMP-1 levels. CONCLUSION: Our results support the notion that levels of both MMP-3 and TIMP-1 in RA patient sera are increased in association with inflammation. Furthermore, the level of MMP-3 in serum provides a particularly useful marker of inflammatory activity in the joints of patients with RA.

Adult↗
PubMed1995

Overlapping and differential expression of BIG-2, BIG-1, TAG-1, and F3: four members of an axon-associated cell adhesion molecule subgroup of the immunoglobulin superfamily.

Axon-associated cell adhesion molecules (AxCAMs) play crucial roles in the formation, maintenance, and plasticity of functional neuronal networks. We report here a molecular cloning of a novel AxCAM, BIG-2. BIG-2 is a member of TAG-1/F3 subgroup of the immunoglobulin (Ig) superfamily, with six Ig-like domains, four fibronectin type III-like repeats, and a glycosyl phosphatidylinositol-anchoring domain. Recombinant BIG-2 protein had a neurite outgrowth-promoting activity when used as a substrate for neurons in vitro. To survey the spatial expression pattern of BIG-2 in comparison with other TAG-1/F3 subgroup members, an in situ hybridization analysis was performed in adult and developing rat brain sections with riboprobes specific for BIG-2, BIG-1, TAG-1, and F3. The four AxCAM transcripts displayed cell type-specific expression patterns with overlapping and distinct profiles. In adult hippocampus, for example, we observed BIG-1 mRNA specifically in granule cells of the dentate gyrus, BIG-2 mRNA highly in the CA1 pyramidal cells, TAG-1 mRNA predominantly in the CA3 pyramidal cells, and F3 mRNA in neurons in all of these fields. These results suggest that BIG-2, BIG-1, TAG-1, and F3 may play important roles in the formation and maintenance of specific neuronal networks in the brain.

Amino Acid Sequence↗
PubMed1995

Use of an SDS-gel-separated protein band as a ligand for affinity chromatography: procedure and application to the purification of domain-specific antibodies against alpha-actinin.

This paper describes a simple and efficient method for preparing affinity columns. We used protein separated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis as a ligand. Protein bands detected in a polyacrylamide gel were electrophoretically transferred to CNBr-activated Sepharose using a buffer containing Nonidet P-40. The amount of ligand protein coupled to activated Sepharose by our method was almost comparable to that obtained by conventional coupling procedure with a native ligand protein. Using affinity columns prepared by this method, we have successfully purified anti-alpha-actinin antibody and antibodies highly specific to the rod domain of alpha-actinin from the antiserum. This new method should be useful for separating a specific antibody from an antiserum that has been raised against multiple antigens. In addition, the use of the SDS-gel-fractionated band facilitates the coupling of proteins that have low solubility under the coupling conditions.

Actinin↗
PubMed1995

Significance of the levels of carboxy terminal type II procollagen peptide, chondroitin sulfate isomers, tissue inhibitor of metalloproteinases, and metalloproteinases in osteoarthritis joint fluid.

The joint fluid levels of several molecules that reflect the anabolism and catabolism of cartilage matrix and its inflammation were quantitated in patients with primary osteoarthritis (OA) and traumatic arthritis. The carboxy terminal type II procollagen increased in primary OA and traumatic arthritis joint fluid and was thought to be a good marker of the repair response of chondrocytes. We found that the increase of this molecule in the joint correlated well with body mass index in primary OA and the degree of cartilage erosion caused by joint instability in traumatic arthritis. Chondroitin 6-sulfate, an integral part of human aggrecan, was also high in OA and traumatic arthritis joint fluids, and showed a similar distribution with keratan sulfate in each disease group. Stromelysin-1 and tissue inhibitor of metalloproteinases-1 levels in joint fluid were very high in RA, but levels in patients with OA were low. Carboxy terminal type II procollagen appeared most sensitive in the evaluation of risk factors of OA such as obesity and joint instability, compared to other markers tested.

Chondroitin Sulfates↗
PubMed1994

Immunohistochemical demonstration of embryonic expression of an odor receptor protein and its zonal distribution in the rat olfactory epithelium.

Using an antibody raised against an odor receptor protein, we investigated immunohistochemically the spatial distribution in the embryonic and adult rat olfactory epithelium of the olfactory receptor neurons that express the odor receptor protein. In adults, the immunoreactive olfactory receptor neurons were intermingled with immuno-negative receptor neurons, but were mostly restricted within a circumferential zone located in the lateral part of the epithelium. The immunoreactive olfactory receptor neurons were observed as early as embryonic day 14, with a strong tendency to localize in the lateral part of the epithelium. These results indicate that both selection of the odor receptor protein by individual olfactory receptor neurons and zonal segregation of the odor receptor protein expression occur early in embryonic development of the olfactory system.

Animals↗