Search PubMed⌕ Search

Biomedical subjects

F Koizumi

Publications and source records attributed to F Koizumi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Lead-induced alteration of heparan sulfate proteoglycans in cultured vascular endothelial cells.

We investigated the alterations of heparan sulfate proteoglycans produced by vascular endothelial cells after exposure to lead. Bovine aortic endothelial cells were cultured and metabolically labeled with [3H]glucosamine and [35S]sulfate in the presence of lead chloride at 10 microM. Radiolabeled HSPGs were separated by ion-exchange chromatography and either their hydrodynamic size or the length of heparan sulfate chains were characterized by gel filtration. It was found that lead markedly suppresses the incorporation of the radioactive precursors into HSPGs in the cell layer; the incorporation into chondroitin/dermatan sulfate proteoglycans was decreased by the metal only slightly. The suppression by lead occurred in the low molecular weight subclass of HSPGs rather than the high molecular weight subclass. However, the length of heparan sulfate chains was not changed by the metal. A sodium dodecyl sulfate-polyacrylamide gel electrophoresis of [35S]methionine-labeled proteoglycans after heparitinase digestion showed that there were slightly more HSPG core proteins without a change of the size in lead-treated cell layer. It was, therefore, suggested that vascular endothelial cell layer after exposure to lead has more HSPG core proteins with fewer heparan sulfate chains without a change in length.

Animals↗
PubMed1997

Basic fibroblast growth factor-induced glycosaminoglycan production in cultured vascular endothelial cells results from enhanced protein synthesis mediated by the lipoxygenase pathway.

To investigate the intracellular regulation of glycosaminoglycan (GAG) production induced by basic fibroblast growth factor (bFGF), bovine aortic endothelial cells were cultured with recombinant human bFGF in the presence of [3H]glucosamine or [35S]sulfate. It was shown that bFGF-induced incorporation of the radioactive precursors into GAGs was diminished by lipoxygenase inhibitors, nordihydroguaiaretic acid (NDGA) and esculetin, but not by a cyclooxygenase inhibitor indomethacin. A protein synthesis inhibitor cycloheximide also diminished the enhancement of the [3H]glucosamine incorporation by bFGF. On the other hand, the incorporation of [14C]leucine into the acid-insoluble fraction was strongly inhibited by NDGA but not by indomethacin in the presence or absence of bFGF. It was also shown that bFGF significantly increased the incorporation of [14C]xylose into GAGs. The present data suggested that bFGF may increase the number of GAG chains as a result of enhanced protein synthesis including xylosyl transferase through the lipoxygenase pathway of arachidonic acid metabolism in vascular endothelial cell layer.

Animals↗
PubMed1996

Phorbol 12-myristate 13-acetate stimulates the release of glycosaminoglycans from cultured vascular endothelial cells: possible involvement of protein kinase C activation.

We investigated the release of glycosaminoglycans (GAGs) labeled with [3H]glucosamine and [35S]sulfate into the medium from cultured bovine aortic endothelial cells stimulated by phorbol 12-myristate 13-acetate (PMA) which is an activator of protein kinase C (PKC). The GAG release was significantly accelerated by PMA without an increase in the leakage of lactate dehydrogenase but was unchanged by 4 alpha-phorbol 12,13-didecanoate which lacks the ability of PKC activation. The acceleration of GAG release by PMA was strongly suppressed by a PKC inhibitor H-7 but not by HA 1004 which is an inactive analogue of H-7. Characterization of GAGs released into the medium revealed that PMA increased both heparan sulfate and the other GAGs in a similar degree. Although the release of GAGs stimulated by thrombin was also suppressed by another PKC inhibitor staurosporine, stimulation by plasmin was unaffected by the inhibitor. The present data suggest that protein kinase C mediates the release of endothelial cell GAGs including anticoagulant heparan sulfate and the stimulation of the release by thrombin includes this mechanism.

Animals↗
PubMed1996

Cyclic AMP-dependent pathway that mediates suppressive regulation of glycosaminoglycan production in cultured vascular endothelial cells.

We investigated the effect of agents which increase the intracellular level of cyclic AMP (cAMP) on the production of glycosaminoglycans (GAGs) by cultured bovine aortic endothelial cells. It was found that the incorporation of [3H] glucosamine into GAGs was significantly decreased by forskolin, 8-bromo cAMP, 3-isobutyl-1- methylxanthine and prostaglandin E1. The leakage of lactate dehydrogenase into the medium, a marker of nonspecific cell damage, were not changed by forskolin. Forskolin-induced decrease in the [3H]glucosamine incorporation occurred in both heparan sulfate and the other GAGs. The [3H]glucosamine incorporation into GAGs was suppressed by forskolin also in human aortic and human umbilical vein endothelial cells, bovine aortic smooth muscle cells, porcine kidney epithelial LLC-PK1 cells and human fetal lung fibroblastic IMR-90 cells. In conclusion, it was suggested that intracellular cAMP mediates the suppressive regulation of GAG production in vascular endothelial cells; as a result, the cell surface heparan sulfate was reduced. The cAMP-dependent pathway appears to be important as an intracellular mechanism by which endothelial production of anticoagulant heparan sulfate is regulated.

1-Methyl-3-isobutylxanthine↗
PubMed1996

Ethosuximide-induced lupus-like syndrome with renal involvement.

A 20-year-old man developed fever and urinary abnormalities with positive antinuclear antibody (ANA) two months after the start of ethosuximide. A renal biopsy showed mild mesangial cell proliferation and cellular crescents predominantly occupying a vascular pole in 7 out of 80 (8.8%) glomeruli. In the arteriole, mainly in close proximity to the glomerulus, proliferation of smooth muscle cells and luminal narrowing were observed. Discontinuation of ethosuximide led to the disappearance of fever, ANA and urinary abnormalities. These findings are strongly suggestive of a causal relationship between ethosuximide and a lupus-like syndrome with peculiar renal involvement.

Adult↗
PubMed1995

Regulation by basic fibroblast growth factor of glycosaminoglycan biosynthesis in cultured vascular endothelial cells.

The alteration of glycosaminoglycans (GAGs) in cultured bovine aortic endothelial cells after exposure to basic fibroblast growth factor (bFGF) was investigated. It was found that the incorporation of [3H]glucosamine into GAGs was markedly increased by bFGF in both the cell layer and the conditioned medium; however, that of [35S]sulfate was not changed by the growth factor. These results indicated that bFGF enhanced the sugar-chain formation but did not affect their sulfation in endothelial GAG production. Similar changes were observed in either bovine aortic smooth-muscle cells and human fibroblastic IMR-90 cells to greater and lesser degrees, respectively. Characterization of GAGs in the endothelial cell layer and the conditioned medium revealed that bFGF enhanced both heparan sulfate and the other GAGs to a similar degree. The present data suggest that bFGF may be involved in the regulation of the blood coagulation system via altering GAGs of the vascular tissue when the endothelium was damaged.

Animals↗
PubMed1995

Co-expression of fibroblastic, histiocytic and smooth muscle cell phenotypes on cultured adherent cells derived from human palatine tonsils: a morphological and immunocytochemical study.

Adherent cells derived from human palatine tonsils were isolated and cultivated. Exponentially growing adherent cells (TAC) were observed by phase-contrast microscopy and transmission electron microscopy. Immunocytochemical studies were also performed. TAC were composed of relatively monotonous cells with polygonal or spindle shapes and high proliferative activity. In addition to the development of rough endoplasmic reticulum and lysosomes, the TAC possessed a moderate amount of pinocytotic vesicles and a few microfilaments. All of the TAC strongly expressed fibroblastic markers and partial monocyte/macrophage markers, such as beta-subunit of prolyl 4-hydroxylase (DAKO-fibroblast), lysozyme, anti-alpha-1-antichymotrypsin (alpha ACT), and CD68 (KP-1, EBM/11). It was noted that, as the TAC were cultured for a longer period, they gradually increased the reactivity with the monoclonal antibody PG-M1. Furthermore, the TAC expressed myocytic phenotype, such as alpha-smooth muscle actin (alpha SMA) with various intensity. Moreover, as to extracellular matrix, TAC stained for collagen type I, collagen type III, laminin, and fibronectin. Collagen type IV was weakly positive. The results presented here showed that the TAC expressed three different phenotypes of fibroblasts, histiocytes and smooth muscle cells at the same time. The monoclonal antibody raised against the TAC reacted strongly with the subendothelial pericytes and/or smooth muscle cells in the extrafollicular area in human tonsils. The present results also suggested that the origin of the TAC was probably subendothelial pericytes and/or smooth muscle cells of the microvasculatures in the tonsil.

Adult↗
PubMed1995

Experimental granulomatous vasculitis induced by sensitization with Ascaris suum antigen in mice.

Experimental sensitization by repeated intramuscular injection of Ascaris suum antigen (Ag-As) supplemented with Freund's incomplete and complete adjuvants was carried out in 50 BALB/c CrSl c male mice (sensitized group) for 24 weeks, and the results were compared with those in a control group of 25 mice. At the injection sites of the sensitized group, granulomatous angiitis with eosinophil infiltration was observed in all mice, and fibrinoid angiitis in only four. By light and electron microscopic examinations pulmonary granulomatous vasculitis with a few eosinophils was observed at a high frequency (80%) after 12 experimental weeks. Immunohistochemical examination revealed pulmonary vascular and perivascular infiltration of L3/T4 (CD4) positive cells, B cells, IgG and C3 positive cells in addition to activated macrophages, Thy-1 T cells, IgE positive cells, and IgM positive cells after 12 experimental weeks. There were significant increases in the eosinophil cell count of the peripheral blood, the hemagglutination titers of the sheep erythrocytes, IgE and IgM antibodies to Ag-As by ELISA and Western blotting after 8 experimental weeks. After 12 experimental weeks the IgG antibody to the Ag-As was low, but it increased significantly, and the sera showed multiple precipitation lines to the Ag-As by the Ouchterlony method. In conclusion, the pulmonary granulomatous vasculitis in this study is considered to consist of allergic reactions of type IV and probably type III based on type I.

Animals↗
PubMed1995

Induction of metallothionein by thrombin in cultured vascular endothelial and smooth muscle cells.

Metallothionein induction by thrombin was investigated using a culture system of vascular endothelial and smooth muscle cells. It was found that the protease induced metallothionein in endothelial cells derived from human aorta and umbilical vein as well as bovine aorta in a concentration-dependent manner. Thrombin also induced metallothionein in vascular smooth muscle cells derived from bovine aorta but not in cells derived from human, rabbit and rat aortas. In bovine aortic endothelial and smooth muscle cells, induction of metallothionein by thrombin was unaffected by the protein kinase C inhibitor staurosporine; in addition, a protein kinase C activator, phorbol 12-myristate 13-acetate, failed to induce metallothionein, suggesting that the induction by thrombin occurred through pathway(s) other than protein kinase C activation. It is suggested that metallothionein may be induced during hemostasis in the vascular tissue through protein kinase C-independent pathway(s).

Animals↗
PubMed1995

Vascular smooth muscle cells in culture are highly sensitive to cadmium cytotoxicity without species-related differences: comparison with Chang liver cells.

Human, rabbit and rat aortic smooth muscle cells (hSMC, rSMC and A10 cells, respectively) were cultured with cadmium chloride and compared with human Chang liver cells to characterize the response of vascular smooth muscle cells to the metal. It was revealed that all tested vascular smooth muscle cells were markedly more sensitive to cadmium cytotoxicity than Chang liver cells. Cadmium accumulated more markedly in vascular smooth muscle cells than in Chang liver cells. After exposure to cadmium, metallothionein was induced in a concentration-dependent manner in Chang liver cells, it was constitutively high in hSMC, sensitively induced in rSMC and was constitutively low and induced within narrow limits in A10 cells. The intracellular content of reduced glutathione was greater and significantly enhanced by cadmium only in A10 cells. The present data suggest that vascular smooth muscle cells are, in general, sensitive to cadmium cytotoxicity without any species-related differences, mainly due to a higher accumulation of the metal within cells.

Animals↗
PubMed1995

Zinc promotes the repair of wounded monolayers of cultured vascular endothelial cells.

The effect of zinc on the repair of wounded monolayers of bovine aortic endothelial cells in a culture system was investigated. It was morphologically found that zinc promotes the appearance of the cells in the wounded area; cell number in the area was significantly increased by zinc. However, other heavy metals including copper, manganese, nickel and cobalt failed to exhibit a similar effect. The repair induced by exogenous basic fibroblast growth factor (bFGF) was potentiated by zinc but that by exogenous acidic fibroblast growth factor was unaffected by the metal. Promotion of the repair of the wounded area by zinc was completely blocked by either cycloheximide or anti-bFGF antibody. In addition, zinc-induced repair was significantly inhibited by a lipoxygenase inhibitor, nordihydroguaiaretic acid but not by a cyclooxygenase inhibitor, indomethacin. From these results, it is suggested that zinc promotes the repair process of damaged vascular endothelium through the lipoxygenase pathway that mediates the response of vascular endothelial cells to endogenous bFGF.

Animals↗
PubMed1994

Plasmin-induced reduction of heparan sulfate in cultured vascular endothelial cell layer.

Plasmin-induced alteration of glycosaminoglycans (GAGs) was investigated using a cell culture system of vascular endothelial cells derived from bovine aorta. In the cell layer, the incorporation of [3H]glucosamine into GAGs, a marker of the sugar chain formation, was slightly decreased by plasmin. On the other hand, the incorporation of [35S]sulfate, a marker of the sulfation, was markedly decreased by the protease. Plasminogen also induced a weak but similar change. Characterization of the cellular GAGs showed that plasmin inhibited the incorporation of both [3H]glucosamine and [35S]sulfate into the major component heparan sulfate at a similar degree. In the other GAGs, the [35S]sulfate incorporation was significantly decreased by plasmin without a change of the [3H]glucosamine incorporation. The leakage of lactate dehydrogenase from the endothelial cells was significantly increased by plasmin, suggesting that the protease exhibited cytotoxicity. The present data suggest that the anticoagulant activity on the surface of vascular endothelium mediated by the anticoagulant heparan sulfate may be reduced by plasmin which will be generated from plasminogen by plasminogen activators derived from endothelial cells.

Animals↗
PubMed1994

Calcium regulation of tissue plasminogen activator and plasminogen activator inhibitor-1 release from cultured human vascular endothelial cells.

Tissue plasminogen activator (t-PA) produced by vascular endothelial cells converts plasminogen to plasmin which degrades fibrin. Since t-PA activity is greatly potentiated in the presence of fibrin (1,2), the activator is implicated in intravascular fibrinolysis. On the other hand, endothelial cells also produce plasminogen activator inhibitor-1 (PAI-1) (3). The inhibitor associated with vascular endothelium rapidly inhibits t-PA, while that released into the liquid phase has a little anti-activator activity (4). However, clinical studies have shown that elevation of plasma PAI-1 level is a risk factor of thrombosis (5,6). It is thus suggested that the balance between t-PA and PAI-1 is important for the regulation of fibrinolysis. The release of t-PA and PAI-1 from vascular endothelial cells is regulated by physiological factors including thrombin (3,7), histamine (8), vasoconstrictor peptide endothelins (9,10) and cytokines (11). In addition, the regulation of the t-PA release and that of the PAI-1 release are not necessarily coupled. It has been shown that activated protein kinase C and cyclic AMP are involved in the stimulation and suppression, respectively, of the endothelial t-PA and PAI-1 production (12,13). However, the role of intracellular calcium in the regulation of endothelial t-PA and PAI-1 release has remained to be elucidated. In the present study, we investigated the effect of calcium ionophore A23187 on the release of t-PA antigen (t-PA:Ag) and PAI-1 antigen (PAI-1:Ag) from cultured vascular endothelial cells derived from human umbilical vein.

Antigens↗
PubMed1994

Basic fibroblast growth factor suppresses tissue plasminogen activator release from cultured human umbilical vein endothelial cells but enhances that from cultured human aortic endothelial cells.

Since basic fibroblast growth factor (bFGF) modulates the functions of vascular endothelial cells, we hypothesized that this factor may be involved in the regulation of the blood coagulation-fibrinolytic system mediated by the cells. Confluent cultures of vascular endothelial cells from human umbilical vein were treated with recombinant human bFGF (bFGF) in a serum-free medium and the content of tissue plasminogen activator antigen (t-PA:Ag) in the medium was determined by EIA. Treatment with bFGF resulted in a significant decrease in the release of t-PA:Ag from the cells accompanied with a less t-PA activity in the medium. In contrast, the t-PA:Ag release from human aortic endothelial cells was significantly increased by bFGF. The bFGF-induced decrease in the t-PA:Ag release from the venous endothelial cells was completely blocked by anti-bFGF antibody. The incorporation of [3H]leucine into the acid-insoluble fraction of the cells was significantly increased by bFGF; however, the activity of lactate dehydrogenase leaked into the medium was significantly decreased, suggesting that the suppression of the t-PA:Ag release caused by bFGF in the venous endothelial cells was not due to either a nonspecific inhibition of protein synthesis or a nonspecific cell damage. Since bFGF is postulated to be released from damaged endothelial cells, the present data suggest the regulation by bFGF of hemostasis mediated by endothelial cells when the vascular endothelium was damaged.

Aorta↗
PubMed1994

Suppression of plasminogen activator inhibitor type 1 release from cultured human umbilical vein endothelial cells by basic fibroblast growth factor.

We investigated the release of plasminogen activator inhibitor type 1 (PAI-1) from cultured vascular endothelial cells after exposure to basic fibroblast growth factor (bFGF). Treatment with human recombinant bFGF of confluent cultures of endothelial cells derived from human umbilical vein resulted in a reduction of the accumulation of PAI-1 antigen (PAI-1:Ag) in the conditioned medium. The suppressive effect of bFGF completely disappeared in the presence of anti-bFGF antibody. The reduction of endothelial PAI-1:Ag release induced by bFGF was suggested to be independent of intracellular accumulation of cyclic AMP. On the other hand, nordihydroguaiaretic acid (NDGA), an inhibitor of the lipoxygenase pathway of arachidonic acid metabolism, suppressed the spontaneous release of PAI-1:Ag by itself; in the presence of NDGA, bFGF failed to further suppress the PAI-1:Ag release. The effect of bFGF and indomethacin, an inhibitor of the cyclooxygenase pathway, was additive on the PAI-1:Ag release. The present data suggest that bFGF reduces the endothelial PAI-1:Ag release via suppression of the putative lipoxygenase pathway which up-regulates a part of the spontaneous PAI-1:Ag release.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

Histological features of palatine tonsils in pustulosis palmaris et plantaris: a morphometric study.

The morphological expression of the immune response of palatine tonsils obtained from patients with pustulosis palmaris et plantaris (PPP) was investigated by morphometry in conjunction with immunohistochemistry. First, to differentiate the histological features of tonsils between PPP and habitual tonsillitis, each extent of the T cell dependent areas (T nodules), B cell dependent areas (lymph follicles), germinal centers, mixed areas of T cells and B cells, and lacunar epithelium was measured and compared on 38 patients with PPP and 47 with habitual tonsillitis, respectively. The most remarkable findings in PPP were enlargement of the secondary T nodules, and atrophy of the lymph follicles with a decrease in number of the germinal center cells and fibrosis. These changes of lymph follicles were similar to those in the older patients with habitual tonsillitis, which suggests the intensely advanced stage of the immune response within the tonsils. Second, the histological structures of the tonsils of 15 tonsillectomy effective cases (88.2%) was compared with those of two non-effective cases in curing skin lesions. The histological structure in the non-effective cases was very similar to that in habitual tonsillitis cases. This indicates that the histological findings may be useful in predicting the effects of tonsillectomy on PPP.

Adult↗