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Biomedical subjects

G Osawa

Publications and source records attributed to G Osawa.

At least 19 recordsLinked to original sources
PubMed2000

Effects of bisphosphonate on matrix metalloproteinase enzymes in human periodontal ligament cells.

BACKGROUND: The host response is a critical component in the pathogenesis of periodontitis. In fact, the clinical benefits associated with regulating the host response have been demonstrated in studies using several different classes of drugs. Biophosphates are one host-modulating class of drugs that has demonstrated this ability. These drugs are clinically effective at reducing bone resorption and have shown the ability to inhibit host degradative enzymes, specifically the matrix metalloproteinases (MMPs). Therefore, the purpose of this study was to investigate the regulatory effects of a bisphosphonate, tiludronate, on MMP levels and activity in human periodontal cells. METHODS: MMP-1 and MMP-3 were assessed in cultured human periodontal ligament cells treated with a bisphosphonate, tiludronate. Reverse transcription-polymerase chain reaction was used to identify mRNA levels for both enzymes, and also for tissue inhibitors (TIMP-1). Enzyme immunoassay (EIA) and immunocytochemistry were used to assess MMP proteins in these cell cultures. Enzyme activity was assessed using FITC-conjugated substrates and quantitated using spectrophotofluorometry. RESULTS: Tiludronate significantly inhibited both MMP-1 and MMP-3 activity in a concentration-dependent manner. A maximal reduction in activity of 35% was achieved for each of the enzymes at a 10(-4) M concentration. Tiludronate did not have a significant effect on the mRNA levels for MMP-1, MMP-3, or TIMP-1. Similarly, there were no effects noted for either MMP-1 or MMP-3 on the protein level. CONCLUSIONS: This study demonstrates an inhibitory effect of tiludronate on the activity of both MMP-1 and MMP-3. These effects appear to occur without altering either mRNA or protein levels for these enzymes, supporting a possible mechanism of action that involves the ability of bisphosphonates to chelate cations from the MMPs. Furthermore, these results support the continued investigation of these drugs as potential therapeutic agents in periodontal disease.

Analysis of Variance↗
PubMed1999

Expression of the fibroblast growth factor receptor 1-4 genes in glomeruli in anti-Thy1.1 mesangial proliferative glomerulonephritis.

Basic fibroblast growth factor (FGF2) is generally known to induce proliferation of cultured mesangial cells and is expressed in proliferative mesangial cells in anti-Thy1.1 mesangial proliferative glomerulonephritis (anti-Thy1.1 GN). The distribution of the FGF receptor (FGFR) has not been studied in anti-Thy1.1 GN, so we used in situ hybridization to determine whether cells expressing FGFR1-4 mRNAs could be detected. In normal rats, all glomeruli were negative for FGFR1-4 mRNA, but those of the mesangial proliferative phase expressed FGFR1-4 mRNA in proliferative mesangial cells. Proliferation of mesangial cells has not been observed in normal rats injected with FGF2( )but it has been noted in anti-Thy1.1 rats injected with FGF2. These data and our results demonstrate that mesangial cells produce and release FGF2( )after injury and that during the proliferative phase these cells upregulate FGFR in vivo. This study is the first to demonstrate expression of FGFR1-4 mRNAs in pathological glomeruli of anti-Thy1.1 GN. The FGF2 and FGFR1-4 genes were expressed in the proliferative mesangial cells. Upregulation of FGFR is necessary for mesangial proliferation by FGF2.

Animals↗
PubMed1998

Molecular genetic and immunohistochemical study of autosomal recessive Alport's syndrome.

A DNA analysis of autosomal type IV collagen alpha3 and alpha4 chain genes (COL4A3 and COL4A4) and an immunohistochemical study of type IV collagen alpha1 to alpha6 chains were performed in an inbred family with autosomal recessive Alport's syndrome (AS). A linkage study using polymorphic markers around the COL4A3/COL4A4 genes clearly differentiated the affected patients from healthy individuals. These patients were homozygous for all markers analyzed, whereas their parents were heterozygotes. Because of the large size of both the genes and the heterogeneous range of the mutations of these genes, linkage analysis by using highly polymorphic markers is still the method of choice in genetic counseling for autosomal recessive AS, as well as for the X-linked form. Although the distribution of alpha1 and alpha2 chains in the index patient and her affected sister were normal, the alpha3 and alpha4 chains were completely defective in the renal basement membrane (BM). The alpha5 chain could be found in Bowman's capsular basement membrane (BCBM) but not in the glomerular basement membrane (GBM). In addition, our study showed, for the first time, that the alpha6 chain in BCBM is spared in this form of AS. This abnormal pattern of type IV collagen could be a useful tool for differentiation of the autosomal recessive type from the X-linked type of AS.

Adolescent↗
PubMed1997

Changes in glomerular epithelial cells induced by FGF2 and FGF2 neutralizing antibody in puromycin aminonucleoside nephropathy.

In the present study, two series of experiments were done with PAN nephropathy rats given fibroblast growth factor 2 (FGF2) or FGF2 neutralizing antibodies. In the first series of experiments, a dose of 10 micrograms of FGF2 (FGF2 group), 40 micrograms of an FGF2 neutralizing antibody (Anti-FGF2 group) or an equal volume of physiological saline (Control group) was administered for four days after PAN injection. Urinary protein increased more in the FGF2 group than in the other two groups. PCNA (+) glomerular cells were found in decreasing order in groups FGF2, Control and Anti-FGF2. Most of the PCNA (+) cells were podocytes and epithelial cells of Bowman's capsule. Staining for desmin, a marker of podocyte injury, was significantly reduced in the Anti-FGF2 group. Glomerular adhesive lesions were found in decreasing order in groups FGF2, Control and Anti-FGF2. The second series of experiments was designed to study the effects of FGF2 neutralizing antibody (40 micrograms for 5 days after PAN injection, in MoAb group) on severely damaged podocytes caused by repeated (two courses) injections in the PAN nephropathy rats. The results were the same as those in series 1. An increase in urinary protein excretion was observed in both groups, but on the 40th day, the level of proteinuria in the MoAb group decreased abruptly. It was observed that the MoAb group had few adhesive glomeruli compared to the IgG group (administration of mouse IgG) and the PCNA (+) epithelial cells of Bowman's capsule were also few. It was supposed that FGF2 would promote the formation of adhesive lesions by stimulating the proliferation of podocytes and epithelial cells of Bowman's capsule. Additionally, FGF2 itself was thought to impair podocytes because of the increasing desmin score and proteinuria.

Animals↗
PubMed1997

Normal distribution of collagen IV in renal basement membranes in Epstein's syndrome.

BACKGROUND: Epstein's syndrome is defined as a subtype of Alport's syndrome, and is distinguished from the other subtypes by accompanying macrothrombocytopenia. Mutations in collagen IV genes are known to be involved in the pathogenesis of typical Alport's syndrome. However, the presence of an underlying genetic defect has not been demonstrated in Epstein's syndrome. AIM: To clarify the involvement of collagen IV in Epstein's syndrome. METHODS: The distribution of the alpha(IV) chain was studied in renal specimens obtained from three patients with Epstein's syndrome using chain specific monoclonal antibodies and an antigen retrieval procedure. RESULTS: The patients showed a normal distribution of alpha(IV) chains: alpha 1(IV) and alpha 2(IV) were expressed ubiquitously, whereas expression of alpha 3(IV) through to alpha 6(IV) chains was limited to the glomerular basement membrane, Bowman's capsular basement membrane, and/or a portion of the tubular basement membrane. CONCLUSIONS: These results suggest that genes other than those encoding alpha(IV) chains are responsible for the pathogenesis of Epstein's syndrome.

Basement Membrane↗
PubMed1997

Primary hyperthyroidism induced erythropoietin-resistant anemia?

We describe a 26-year-old male hemodialysis patient with erythropoietin (EPO) resistant anemia associated with primary hyperthyroidism. Use of the anti-hyperthyroid drug, methimazole, led to improvement of his hyperthyroidism and anemia. Before the anti-hyperthyroid therapy, he had received transfusions to maintain an adequate hematocrit during recombinant human EPO therapy. After the therapy, his hyperthyroidism improved and his hematocrit gradually increased without any transfusion. These findings suggest that the patient's EPO resistant anemia was the result of primary hyperthyroidism, and that this complication is reversible if accurate treatment is given.

Adult↗
PubMed1997

[Study on coagulation fibrinolytic systems in predialysis patients with chronic renal failure--comparison between patients with chronic glomerulonephritis and patients with diabetic nephropathy].

To clarify the abnormalities of coagulation and fibrinolytic systems on predialysis patients with chronic renal failure, we measured indices of coagulation and fibrinolytic systems in 33 predialysis patients whose creatinine (Cr) levels were over 3.0 mg/dl. We termed twenty-four patients with chronic glomerulonephritis the "CGN group". We also termed nine patients wit diabetes mellitus the "DM group". We measured thrombin.antithrombin III complex (TAT), alpha 2-plasmin inhibitor plasmin complex (PIC), D-dimer, protein C, protein S, thrombomodulin (TM), vitronectin, tissue plasminogen activator.plasminogen activator inhibitor-1 complex (tPAI-C) in theses two groups. Furthermore, we measured the same indices after 6 months in the CGN group. As a result, the plasma levels of both TAT, PIC, TM/Cr ration in the DM group were significantly higher that those in the CGN group, changes in both protein S activities and plasma levels of tPAI-C were reduced significantly after 6 months. In conclusion, the abnormalities of coagulation and fibrinolytic systems in predialysis diabetic patients were stronger than those in predialysis patients with CGN. Furthermore, these abnormalities were worsened after 6 months in predialysis patients with chronic renal failure.

Adult↗
PubMed1996

Gallium 67 scintigraphy as a predictor of renal prognosis in primary immunoglobulin A nephropathy.

From October 1987 to September 1989, 29 patients with newly diagnosed immunoglobulin A nephropathy underwent renal gallium 67 scintigraphy. The radioisotope uptake ratio between left kidney and soft tissue was measured 48 hours after bolus injection of gallium 67. In 25 patients the ratio ranged from 1.30 to 3.56 (mean, 1.95 +/- 0.47). Ratios were not obtained in four patients because strong gastrointestinal isotope excretion. Plots of reciprocal serum creatinine concentration against time and Kaplan-Meier plots of renal survival were used to assess the predictive value of the test in 20 patients for whom long-term follow-up data were available. The radioisotope uptake ratio was negatively correlated with the slope of reciprocal serum creatinine against time (r = -0.64, P < 0.01). When the 20 patients were divided into two groups according to radioisotope uptake ratio (group A, ratio > 1.95, nine patients; group B, ratio < 1.95, 11 patients), life table analysis of renal survival showed group B to have a better prognosis than group A (P < 0.05). The results indicate that increased renal gallium uptake is predictive of a poor prognosis in patients with immunoglobulin A nephropathy.

Adult↗