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Biomedical subjects

N Fujimoto

Publications and source records attributed to N Fujimoto.

At least 163 records · Page 9Linked to original sources
PubMed1995

Coordinate regulation of matrix metalloproteases and tissue inhibitor of metalloproteinase expression in human synovial fibroblasts.

We examined the common signal transduction mechanisms governing collagenase (MMP-1), stromelysin-1 (MMP-3), and tissue inhibitor of metalloproteases (TIMP-1) gene expression in human synovial fibroblasts for insight into the pathophysiology of arthritis. MMP-1, MMP-3, and TIMP-1 expression and synthesis were induced in cultured human synoviocytes with recombinant human interleukin 1 beta in the absence or presence of either chemical inhibitors of protein kinase A and C (PKA, PKC), or prostaglandin E2, or cyclic AMP (cAMP) mimetics. We used enzyme immunoassays (EIA) to determine MMP-1, MMP-3, and TIMP-1 antigen levels in spent culture medium and Northern hybridization to measure steady state mRNA expression levels. Extracellular signals (e.g., IL-1, phorbol myristic acetate) that result in the activation of cytoplasmic PKC augment in tandem the expression and synthesis of MMP-1, MMP-3, and TIMP-1 in human synovial fibroblasts. In addition, such signals induce nuclear transcription factors (e.g., activator protein 1) that bind to common gene regulatory elements and augment promoter activity of MMP-1, MMP-3, and TIMP-1 gene promoter constructs. In contrast, signals that activate PKA oppose PKC mediated signals, in that the expression of MMP-1, MMP-3, and TIMP-1 are suppressed. Experimental data suggest that the expression of MMP-1, MMP-3, and TIMP-1 are coordinated through a series of common cytoplasmic signal transducing pathways, cis regulatory elements, and nuclear trans acting factors.

Cells, Cultured↗
PubMed1995

Localization of matrix metalloproteinase 9 (92-kilodalton gelatinase/type IV collagenase = gelatinase B) in osteoclasts: implications for bone resorption.

BACKGROUND: Matrix metalloproteinase 9 (MMP-9, 92-kD gelatinase/type IV collagenase = gelatinase B) is a member of the MMP gene family and implicated in tissue destruction in the various pathophysiologic conditions. Our previous study showed that MMP-9 purified from human fibrosarcoma cells can cleave the cross-link-containing NH(2)-terminal telopeptides of the alpha 2 chain of type I collagen and collagen types III, IV, and V as well as gelatins. EXPERIMENTAL DESIGN: To investigate the role of MMP-9 in bone resorption we have examined its localization in the human bone tissues by immunohistochemistry and in situ hybridization. The enzymic properties were also biochemically studied. RESULTS: Immunohistochemistry using monoclonal antibodies against MMP-1 (interstitial collagenase), MMP-2 (72-kD gelatinase/type IV collagenase = gelatinase A), MMP-3 (stromelysin-1), MMP-9, and tissue inhibitor of metalloproteinases-1 demonstrated that MMP-9 is localized exclusively in osteoclasts of the bone tissues from normal subjects and patients with rheumatoid arthritis or metastatic carcinoma whereas some osteoclasts are also labeled by anti-(MMP-1) antibody. Northern blot and in situ hybridizations of rheumatoid bone tissues using a RNA probe for MMP-9 exhibited strong signals for the mRNA within osteoclasts. MMP-9 depolymerized acid-insoluble polymers of type I collagen and digested collagen fibrils in the demineralized bone. The gelatinolytic activity of the proteinase was optimal at pH 7.5, but 50 to 80% of the full activity was retained at pH 5.5 to 6.0. It was also 90% active in the presence of 100 mM Ca2+. Degradation of acid-soluble and -insoluble type I collagens by MMP-9 was enhanced at higher concentrations of Ca2+. The zymogen of MMP-9 was activated up to approximately 85% of full activity by incubation at pH 2.3. CONCLUSIONS: These results demonstrate that MMP-9 is produced by osteoclasts in the human bone tissues and suggest that it can degrade bone collagens in concert with MMP-1 and cysteine proteinases in the subosteoclastic microenvironment. This proteinase may play a role in the normal bone remodeling and pathologic bone resorption in the human diseases.

Adolescent↗
PubMed1995

Production of matrix metalloproteinases at the bone-implant interface in loose total hip replacements.

BACKGROUND: Incidence of aseptic loosening of hip prostheses is increasing in recent years. Previous studies suggested involvement of proteinases and cytokines in the accelerated bone lysis associated with loosening. EXPERIMENTAL DESIGN: To investigate the role of matrix metalloproteinases (MMPs) in the loosening we immunolocalized MMP-1 (tissue collagenase), MMP-2 (gelatinase A), MMP-3 (stromelysin-1), MMP-9 (gelatinase B) and their common inhibitors, tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), in the bone-prosthesis interface membranes. In situ hybridization was performed for the detection of MMP-9 mRNA in the membranes. The amounts of these MMPs and TIMPs in the tissue were measured by the sandwich enzyme immunoassays and enzyme activities assayed using radiolabeled collagen, gelatin, and carboxymethylated transferrin substrates. We also examined the ability of the cells from interface membranes to resorb mouse calvaria bone. RESULTS: The membranes obtained from the loose bone-implant interface were composed of fibrous granulation tissue containing numerous multinucleated giant cells with high density polyethylene debris. Immunohistochemical examination revealed that the giant cells were strongly positive for MMP-9 and weakly for MMP-1. Expression of MMP-9 mRNA in the cells was demonstrated by in situ hybridization. MMP-2 and TIMP-2 were immunolocalized mainly in the fibroblasts. TIMP-1 was localized in the endothelial cells of the blood vessels and weakly in fibroblasts. However, MMP-3 was almost negative in the membrane tissue. Sandwich enzyme immunoassays showed that MMP-9 levels are significantly higher in both homogenates and culture media of the cup and stem interface membranes than the control pseudocapsule. Gelatinolytic activity was also remarkably higher in the membrane samples than the control. The cells isolated from the membranes had no ability to resorb calvaria bone. CONCLUSIONS: These data demonstrate that MMP-9 is produced by the multinucleated giant cells appeared by the reaction to polyethylene debris in the interface membranes. This proteinase may play a role in degradation of the extracellular matrix macromolecules present around and on the surface of the bone trabeculae, facilitating the osteoclastic bone resorption.

Adult↗
PubMed1995

[The correlation of the thalamic lesions on MRI with cerebral cortical blood flow in patients with lacunar infarction].

We performed MRI and measured cerebral blood flow (CBF) using 123I-IMP SPECT microsphere model in twenty three right-handed patients with lacunar infarction. Twelve of 23 patients showed chronic deterioration of dysarthria and gait disturbance. The mental function of the patients was evaluated by the Mini-Mental State (MMS) examination. The area of high intensity on T2-weighted images was quantitatively analyzed in the cerebral white matter (WM), lenticular nucleus (LN) and thalamus (THA). The score of MMS was positively correlated with the local CBF in the bilateral frontal, parietal, temporal and occipital cortices (p < 0.05). Also, the area of high intensity in the left THA showed a significant negative correlation with local CBF of the bilateral frontal, parietal, temporal and occipital cortices (p < 0.001). The high intensity areas of the bilateral LN, right WM and right THA had a significant but weaker negative correlation with local CBF of some cortices. These findings suggest that thalamic lesions on the dominant side play an important role in the reduction of cortical blood flow and the deterioration of mental functions in patients with lacunar infarction.

Aged↗
PubMed1994

Serum levels of collagenase, stromelysin-1, and TIMP-1. Age- and sex-related differences in normal subjects and relationship to the extent of joint involvement and serum levels of antigenic keratan sulfate in patients with osteoarthritis.

OBJECTIVE: To measure serum levels of collagenase (MMP-1), stromelysin-1 (MMP-3), and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) in normal subjects and in patients with osteoarthritis (OA), and to assess how these correlate with biochemical and clinical indicators of disease activity in OA. METHODS: Specific immunoassays were used to measure MMPs, TIMP-1, and antigenic keratan sulfate (KS). The total area of cartilage affected by the disease was measured (expressed as an articular index). RESULTS: In the normal population (n = 118), the serum concentration of MMP-3, but not of MMP-1 or TIMP-1, increased with age and was approximately 2 times higher in males than in females. In the OA patients (n = 33), the serum levels of MMP-3, but not of MMP-1 or TIMP-1, were significantly elevated and correlated strongly with the articular index but poorly with objective and subjective functional capacity scores as well as with serum levels of antigenic KS and systemic parameters of inflammation. CONCLUSION: These findings illustrate the importance of matching patients and normal controls for age and sex in further studies of MMP-3 and are consistent with the hypothesis that MMP-3 might play an important role in the degradation of joint cartilage in OA. Further, serum levels of MMP-3 may prove useful for monitoring therapy for OA.

Aged↗
PubMed1994

Tumorigenicity study of phloxine (FR 104) in B6C3F1 mice.

The aim of this study was to examine the tumorigenicity of the food colouring phloxine (Food Red 104) in (C57BL/6N x C3H/HeN) F1 mice. Groups of male or female mice received 0, 0.1 and 0.4% phloxine in the diet starting at 6 wk of age for a maximum of 90 wk. Survivals of mice were more than 85% at 64 wk after the start of phloxine administration. Their body weights reached maximum at 48 wk and both male and female mice given 0.1 and 0.4% phloxine weighed significantly more than their respective controls. Tumours developed in 13 organs, the greatest incidence in males being of liver tumours (67.3%), followed by lung tumours (10.9%), lymphomas (9.7%), altered foci of liver (8.4%) and hepatic haemangioma (7.8%). In females, hepatic tumours (11.5%) had the greatest incidence followed by lymphomas (10.8%), pulmonary tumours (8.2%) and hepatic haemangioma (3.2%). In males, the incidence of altered foci and haemangioma in the liver was 19 and 14%, respectively, in the control groups, whereas only 2% occurred in the group given 0.4% phloxine (P < 0.05). It is concluded that average body weights increased significantly in female mice of groups given 0.1 or 0.4% phloxine, compared with body weights of the female controls, and that altered liver foci were significantly reduced in male mice given 0.4% phloxine. There was a significant increase in pituitary tumour incidence in the test groups compared with the control groups.

Animals↗
PubMed1994

Inhibition of mammary tumors by pretreatment with 17 beta-estradiol in F344 rats induced with N-methyl-N-nitrosourea.

The influence of 17 beta-estradiol (E2) and prolactin was studied on N-methyl-N-nitrosourea (MNU)-induced mammary carcinomas (MCAs) in rats. MNU was intravenously injected once into seven-week-old female. female F344 rats at a dose of 50 mg/kg body weight. Groups of rats also received either 2.5 mg of E2 or a continuous supply of prolactin and/or growth hormone via transplanted MtT/F84 (mammo-somatotropic pituitary tumor). Rats were observed for up to 36 weeks after MNU administration. Although simultaneous administration of MNU and E2 did not much affect the occurrence of MCAs as compared to administration of MNU alone, rats treated with 2.5 mg of E2 for two weeks before MNU administration had significantly reduced occurrence of MCAs compared to those given MNU alone. In contrast, rats with MNU plus MtT/F84 showed high incidence and shortened latency of MCAs and they also had a high incidence of clitorial gland hyperplasias. Average pituitary weights and serum prolactin levels in E2-treated rats were greatly increased compared to those of MNU-alone rats. Average serum E2 levels were about 100 ng/ml in E2-treated rats and 0.05 ng/ml in rats without E2 treatment. Serum prolactin levels were greatly increased in rats with MtT/F84. The results indicated that pretreatment with E2 before MNU administration was inhibitory while increased prolactin caused by grafting MtT/F84 after MNU injection was promotive for the occurrence of MCAs in female F344 rats.

Adenocarcinoma↗
PubMed1994

Long-term graft survival rate of zero-mismatch kidney transplants for HLA-DRB1.

The study of a two-locus association between HLA-B and -DRB 1 revealed a significant 43 linkage disequilibrium. Donor-recipient HLA-DRB1 was determined by these 43 linkages. Zero-mismatch for HLA-DRB1 had a significant effect on the graft survival rate in living related and cadaver transplants. The 5-year graft survival rate was 94% in the zero-mismatch group for HLA-DRB1, 96% for related transplants, 92% for cadaver cases, and 94% in HLA identical siblings. A statistically significant difference was found between the zero-mismatch group for HLA-DRB1 and mismatch groups for HLA-DRB1 or HLA-DR (P < 0.01). The zero-mismatch group for HLA-DRB1 had mismatches for HLA-A and/or HLA-B in 46 of 70 cases (66%). No significant differences in the rejection rate was observed between zero-mismatch and mismatch cases for HLA-A and/or -B in the zero-mismatch group for HLA-DRB1. In the second step, genotyping was conducted in 118 cases. The 5-year graft survival rate was 93% in the zero-mismatch group for HLA-DRB1 and 86% in mismatch group (not a significant difference). We concluded that zero-mismatch transplant for HLA-DRB1 had a better long-term graft survival rate regardless of HLA class I.

Cyclosporine↗
PubMed1994

The impact of hepatitis C virus infection on liver disease in renal transplant recipients.

To assess the prevalence of hepatitis C virus (HCV) infection in renal transplant recipients and its impact on posttransplant liver disease, the sera from 176 recipients who had been followed for 1-20 years (mean 8.3 years) were tested for HCV-specific antibody using enzyme immunoassay. HCV-specific antibody was detected in 53 patients (30.1%) including 2 patients also positive for hepatitis B surface antigen (HBsAg). Among 167 HBsAg-negative patients, the presence of HCV-specific antibody was associated with an increased incidence of chemically significant hepatitis (70.6% vs. 9.5% in anti-HCV-negative patients, P < 0.01). Hepatitis was more likely to be chronic in anti-HCV-positive patients than in anti-HCV-negative patients (P<0.05). Serious liver disease developed in 4 of 51 anti-HCV-positive, HBsAg-negative patients: liver failure causing death in 3 and hepatoma in 1. Liver biopsy specimens from anti-HCV-positive patients showed more aggressive histological lesions compared with those from anti-HCV-negative patients. We conclude that HCV infection is quite prevalent in our renal transplant recipients and plays a major role in posttransplant chronic liver disease.

Alanine Transaminase↗