Biomedical subjects

A Ooshima

Publications and source records attributed to A Ooshima.

At least 55 records · Page 3Linked to original sources

PubMed1997

Effects of oestrogen on the extracellular matrix in the endometrium of postmenopausal women.

AIM: To obtain insight into the effects of oestrogen on extracellular matrix (ECM) in the postmenopausal endometrium. METHODS: The distribution of the components of the ECM, including collagen types I, III, IV, and VI, and laminin, was investigated in the human postmenopausal endometrium by an indirect immunofluorescence method with specific monoclonal antibodies and a polyclonal antibody. Collagens were also extracted from the endometrial tissues of postmenopausal women who had or had not been treated with oestrogen for three weeks. RESULTS: Immunohistochemical studies demonstrated that type I collagen was the predominant interstitial collagen, and that types III and VI collagens were absent or very sparsely distributed in the stroma of the postmenopausal endometrium. However, types I, III, and VI collagens were diffusely localised in the stroma of the postmenopausal endometrium after administration of oestrogen. Even though type IV collagen was not seen in the basement membrane of the endometrial glands in the endometrium of postmenopausal women in the absence of oestrogen treatment, both type IV collagen and laminin were localised exclusively in the basement membrane of the endometrial glands in the postmenopausal endometrium after three weeks of oestrogen treatment. The level of type III collagen relative to that of type I collagen was significantly increased (p < 0.01) in the endometrium of oestrogen treated postmenopausal women compared with non-treated postmenopausal women. CONCLUSIONS: Conjugated equine oestrogen might induce changes in the distribution of components and in the composition of the ECM in the endometrium of postmenopausal women.

Aged↗

PubMed1997

In vitro effects of doxorubicin and mitomycin C on human Tenon's capsule fibroblasts.

Doxorubicin is an antiproliferative agent, that also inhibits prolyl 4-hydroxylase in vitro. We evaluated the effects of doxorubicin and mitomycin C (MMC) on the proliferation of human Tenon's capsule fibroblasts and the secretion of type I collagen in these cells to explore the potential use of doxorubicin as an antifibrotic agent after glaucoma filtering surgery. Standard immunoassays were used to determine the concentrations of type I procollagen COOH-terminal peptide (PIP), laminin and vitronectin receptor in conditioned media and cell lysates in the presence or absence of doxorubicin or MMC. The mitotic activity and viability of these cells were also determined. Cellular ultrastructure was evaluated by transmission electron microscopy. Doxorubicin and MMC decreased the cellular viability, the mitotic activity, and the production of the peptides measured. The inhibition of PIP secretion into the culture medium was higher in doxorubicin-treated cultures than in MMC-treated cultures at the tested concentrations (5-100 microM). The decrease in PIP levels in cell lysates was less in doxorubicin-treated culture (25 microM) than in MMC-treated culture (25 microM), suggesting that procollagen synthesis and secretion might be attenuated by doxorubicin. Ultrastructural studies revealed increased numbers of lysosomes in the cytoplasm of doxorubicin-treated cells relative to MMC-treated cells. Doxorubicin and MMC reduced cell viability and inhibited the proliferation and synthesis of PIP, laminin, and vitronectin receptor peptide. Inhibitory effects of doxorubicin on PIP secretion were more potent than those of MMC. Doxorubicin may be useful for inhibiting the fibrotic response at the site of ocular filtering surgery.

Adult↗

PubMed1997

Stretch-induced proliferation of cultured vascular smooth muscle cells and a possible involvement of local renin-angiotensin system and platelet-derived growth factor (PDGF).

This experiment was designed to investigate the possible involvement of angiotensin II (Ang II) and platelet-derived growth factor (PDGF) in the mechanism underlying stretch-induced proliferation of vascular smooth muscle cells (SMCs). SMCs from the rabbit aortic media were grown on polystyrene rubber-bottomed dishes coated with type I collagen. Cells were stretched cyclically by a vacuum-operated downward flexion of the culture dish bottom. A 1.4- to 1.6-fold increase in proliferation of SMCs was induced by cyclic stretching, as determined by [3H]-thymidine incorporation, in a stretch force-dependent manner in the range of 5% to 15% elongation, 30 cycles/min for 24 h. Expression of PDGF-B chain mRNA was up-regulated in a time-dependent manner in the range of 2 to 24 h, 10% elongation, and 30 cycles/min. Saralasin, a selective antagonist of Ang II, and captopril, an angiotensin I converting enzyme inhibitor, significantly suppressed the stretch-induced proliferation of SMCs. Blockade of angiotensinogen mRNA translation by antisense oligonucleotide inhibited proliferation under the mechanical strain. Stretch-induced proliferation was inhibited by 78% in the presence of anti-PDGF-AB neutralizing antibody. Increased expression of PDGF-B chain mRNA under the mechanical strain was inhibited by treatment with saralasin. Our results indicate that the stretch-induced proliferation of cultured SMCs is mediated at least in part via increased production of Ang II by the local renin-angiotensin system and a subsequent up-regulation of PDGF-B chain mRNA in an autocrine-paracrine manner.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1996

Adenovirus-mediated transfer of a truncated transforming growth factor-beta (TGF-beta) type II receptor completely and specifically abolishes diverse signaling by TGF-beta in vascular wall cells in primary culture.

We constructed an adenoviral vector expressing a mutated human type II transforming growth factor-beta (TGF-beta) receptor that was truncated of its kinase domain (AdexCATbetaTR) and examined whether this truncated receptor could abolish signaling by TGF-beta using arterial endothelial cells and smooth muscle cells, as well as a lung epithelial cell line (Mv1Lu). Infection of cells with AdexCATbetaTR induced expression of the truncated receptor, the amount of which would be excessive compared with those of both full-length type I and type II receptors, as assessed by levels of their mRNAs. The antiproliferative effect of TGF-beta was completely eliminated in both endothelial cells and Mv1Lu that were infected with AdexCATbetaTR. The transcriptional activation by TGF-beta of plasminogen activator inhibitor-1 and fibronectin was entirely suppressed. Abrogation of the TGF-beta-enhanced production of type I collagen in infected smooth muscle cells was confirmed by immunocytostaining and by [14C]proline incorporation in a quantitative manner. Mitogenic response to other growth factors remained unaffected in infected cells. Our data demonstrated that the adenovirus-mediated transfer of a truncated type II TGF-beta receptor completely and specifically abolishes the diverse effects of TGF-beta as a dominant-negative mutation, supporting the hypothesis that both the type I and type II receptors are required for all signaling by TGF-beta. This method may facilitate the clarification of the role of TGF-beta both in vitro and in vivo.

Adenoviridae↗

PubMed1996

Collagen synthesis in lens epithelial cells on capsules containing intraocular lens implants in rabbits: immunolocalization of prolyl 4-hydroxylase.

BACKGROUND: We evaluated ultrastructurally the presence and distribution of lens epithelial cells and extracellular matrix on the posterior capsule after implantation of a silicone or a polymethyl-methacrylate (PMMA) intraocular lens (IOL) in rabbits. The immunolocalization of prolyl 4-hydroxylase, an enzyme involved in procollagen synthesis, was also examined in such cells. METHODS: Anesthetized adult albino rabbits (n = 12) underwent phacoemulsification and aspiration (PEA) of the crystalline lens and implantation of a silicone or a PMMA IOL into the capsular bag of one eye. They were killed by an intravenous overdose of pentobarbital sodium. The lens capsules were processed for transmission electron microscopy and for immunohistochemical detection of the beta-subunit of prolyl 4-hydroxylase. RESULTS: Ultrastructurally, lens epithelial cells on the posterior capsule evidenced an accumulation of collagenous extracellular matrix. Prolyl 4-hydroxylase immunoreactivity was detected in the cytoplasm of cells distributed on the capsules. CONCLUSION: Lens epithelial cells are involved in the production of collagenous matrix on lens capsules after PEA and implantation of IOL, resulting in a fibrotic process of the lens capsule.

Animals↗

PubMed1996

Immunolocalization of prolyl 4-hydroxylase in fibroblasts cultured from Tenon's capsule of humans.

BACKGROUND: The excessive accumulation of extracellular matrix (ECM) with the repopulation of fibroblasts may lead to an unsuccessful outcome of glaucoma filtering surgery. We examined the immunolocalization of ECM components and prolyl 4-hydroxylase, an enzyme involved in collagen biosynthesis, in cultured Tenon's capsule fibroblasts (TCFs) of humans to evaluate the production of ECM in the cells. METHODS: We used light microscopy to evaluate the immunolocalization of prolyl 4-hydroxylase and ECM components, collagen types I, III, and IV, cellular fibronectin, and laminin in TCFs. Ultrastructural localization of the enzyme was also evaluated by electron microscopy. RESULTS: Immunoreactivity with monoclonal antibodies against the alpha and beta subunits of the enzyme or with the polyclonal antibody against it was detected in the cytoplasm of the cells in a fine granular pattern, indicating its localization in the endoplasmic reticulum (ER). Immunoreactivity for the enzyme was detected in the cisternae of the ER on electron microscopy. Types I and III collagen reactivities were also observed in the cytoplasm in a fine granular pattern. Type IV collagen reactivity was present diffusely on the cell surface. The distribution of laminin reactivity in the cytoplasm resembled that of types I and III collagen. Cellular fibronectin reactivity was observed in the ECM in a reticular pattern. CONCLUSION: Prolyl 4-hydroxylase was located in the cisternae of the ER. TCFs produced a variety of ECM components in vitro. The results provide insight into the fibrotic process during scar formation at the site of a bleb following filtering surgery.

Aged↗

PubMed1996

Effect of fibrostatin C, an inhibitor of prolyl 4-hydroxylase, on collagen secretion by human Tenon's capsule fibroblasts in vitro.

PURPOSE: To investigate the effect of fibrostatin C, a prolyl 4-hydroxylase (PH) inhibitor produced by Streptomyces catenulae subsp. griseospora, on type I collagen secretion by human Tenon's capsule fibroblasts (TCFs) in vitro, as an indication of the potential therapeutic efficacy of this compound in antifibrotic therapy after glaucoma filtering surgery. METHODS: The concentrations of type II procollagen COOH-terminal peptide (PIP) in culture medium or cell lysate were determined by immunoassays. For comparison with its effect on PIP secretion, we determined the effects of the agent on the secretion of other peptides, including laminin, vitronectin receptor, and a metalloproteinase inhibitor. The expression of collagens I and III, fibronectin, and PH by TCFs was examined by immunohistochemistry, and cellular ultrastructure was evaluated by transmission electron microscopy. RESULTS: Fibrostatin C (50 microM) significantly reduced the concentration of PIP in culture medium and increased its concentration in the cell lysate in a dose-dependent manner, but it had no effect on the secretion of other peptides. Cell viability and proliferation were not affected by fibrostatin C. Fibrostatin C also increased the number of cytoplasmic granules immunoreactive with antibodies to collagen I or III, but had no effect on fibronectin or PH immunoreactivity. Ultrastructurally, cisternae of the endoplasmic reticulum were dilated in fibrostatin C-treated TCFs, consistent with the retention of underhydroxylated collagen precursors in this organelle. CONCLUSIONS: Fibrostatin C inhibits the secretion of type I collagen by cultured TCFs. This agent may thus prove therapeutically beneficial for inhibiting the excess fibrosis in the wound of filtering surgery.

Aged↗

PubMed1996

Detection of lysyl oxidase gene expression in rat skin during wound healing.

Lysyl oxidase (LOX) initiates the crosslinking of the lysine-derived aldehyde and plays an essential role in maturation of collagen, for example in wound healing. Although the activity of this enzyme has been examined in various disorders, and a further intriguing aspect of the relationship between LOX and tumorigenesis has recently emerged, its gene expression pattern in tissues is still unknown. We examined LOX gene expression during wound healing in rat skin. In addition, type III collagen gene expression was studied to determine the formation of fibrils. The LOX mRNA level reached a peak by day 3 after injury, which was earlier than that of type III collagen, and continued at a high level until day 22. The type III collagen mRNA level began to rise from day 3 and had increased intensely by day 22. In situ hybridization revealed grains corresponding to LOX mRNA in the fibroblasts of the granulomatous tissue. These results suggest that LOX is produced before collagen synthesis in preparation for crosslinking in the early phase of wound healing.

Animals↗

PubMed1996

Lens epithelial cell outgrowth and matrix formation on intraocular lenses in rabbit eyes.

PURPOSE: To evaluate the presence and distribution of lens epithelial cells (LECs) and extracellular matrix on intraocular lenses (IOLs) implanted in the capsular bag in rabbit eyes. SETTING: Department of Ophthalmology, Wakayama Medical College, Wakayama, Japan. METHODS: Five adult albino rabbits had phacoemulsification and IOL implantation in both eyes. Two or 11 months later, the animals were killed by intravenous pentobarbital. The IOLs were removed and observed under scanning and transmission electron microscopy. RESULTS: In addition to the macrophages and giant cells on the IOLs, all eyes had a monolayer of flattened cells growing out from the residual anterior lens capsule and a fibrous meshwork of extracellular matrix. Unlike those of a macrophagic origin, these cells had no central cytoplasmic elevation of nuclei and few cell surface microvilli and were considered to be proliferating LECs. CONCLUSION: Lens epithelial cells are involved in the eye's cellular reaction to IOLs and in the formation of extracellular matrix on IOLs. Further study of LEC behavior on IOLs should be done to improve IOL biocompatibility.

Animals↗

PubMed1996

Increase in the relative level of type V collagen during development and ageing of the placenta.

AIM: To obtain some insight into the extracellular matrix in the placenta, changes in the composition of collagens during placental development were investigated. METHODS: Collagen was extracted from placentas (group 1, 25-30 weeks, n = 21; group 2, 31-36 weeks, n = 32; and group 3, 37-41 weeks of gestation, n = 40) and the relative concentrations of various collagens were evaluated by SDS-PAGE. RESULTS: The ratio of the intensity of the alpha 1 (III) band to that of alpha 1 (I) chain collagen in group 3 placentas were lower than those in group 1 placentas. In contrast, the ratio of the intensity of the alpha 1 (V) band to that of alpha 1 (I) chain collagen in group 3 placentas were higher than those in group 1 and group 2 placentas. CONCLUSIONS: These results suggest that type V collagen might play an important role in the function of the placenta and that an increased relative concentration of type V collagen might be closely associated with the development and ageing of the placenta.

Adult↗

PubMed1996

Pentoxifylline and pentifylline inhibit proliferation of human Tenon's capsule fibroblasts and production of type-I collagen and laminin in vitro.

After glaucoma filtering surgery, an excessive repopulation of Tenon's capsule fibroblasts (TCFs) with the accumulation of extracellular matrix including collagen types during wound healing may cause scarring of the bleb, resulting in surgical failure. Pentoxifylline (PTX) and pentifylline (PTF), both methylxanthine derivatives, are known to inhibit protein synthesis and proliferation of cells in vitro. We examined the effects of these agents on the proliferation of cultured human TCFs and their production of type-I collagen COOH-terminal peptide (PIP) and laminin to investigate the potential use of the agents as antifibrotic agents after filtering surgery. Both agents inhibited the proliferation of cultured human TCFs and their production of PIP and laminin. The inhibitory effects of PTF on proliferation and production of PIP and laminin were greater than those of PTX. These methylxanthine derivatives may have clinical utility in preventing excessive bleb scarring after glaucoma filtering surgery.

Adult↗

PubMed1996

MR imaging of liver cirrhosis.

PURPOSE: The objective of this study was to identify the factors affecting the visualization of regenerating nodules in cirrhotic liver by MR imaging. MATERIAL AND METHODS: MR images from patients with liver cirrhosis and normal subjects were studied, and signal intensity within the liver was measured and correlated with histologic findings. A reference phantom was also used as a standard. RESULTS: The signal intensity of the liver on T2-weighted (T2WI) spin-echo (SE) images was significantly increased in patients with liver cirrhosis. Multiple ring-like or reticular high-intensity areas (RHAs) were demonstrated on T2WI SE images in 44 of 125 cirrhotic livers. Histologic examination in 44 cases revealed various degrees of inflammatory changes in fibrous septa surrounding regenerative nodules in all specimens, vascular dilation in fibrous septa in 4 specimens, and no hemosiderin deposition in some specimens. The results of linear discriminant analysis showed that inflammatory changes in fibrous septa were significantly more pronounced in cases with RHAs on MR. CONCLUSION: RHAs seen on T2WI SE images may correspond to fibrous septa with inflammation. The signal intensity of fibrous septa surrounding regenerative nodules on T2WI SE images may be increased in liver cirrhosis due to inflammation or vascular dilation, contributing to the visualization of regenerating nodules as relatively low-intensity regions on MR.

Adult↗

PubMed1996

Decreased type IV collagen expression by human decidual tissues in spontaneous abortion.

To provide some insight into the etiology of spontaneous abortion, the expression of type IV collagen was investigated in human decidual tissues obtained after spontaneous abortion (n = 17) and normal pregnancy (n = 22). Indirect immunofluorescent staining was performed for type I, III, and IV collagen as well as laminin, and Northern blot analysis was conducted to assess the expression of messenger ribonucleic acid for the alpha 1(IV) chain. Immunohistochemical analysis did not reveal any significant differences between normal pregnancy and spontaneous abortion with respect to interstitial collagens (type I and III collagen) and laminin in the decidual tissue. However, although pericellular immunostaining for type IV collagen was recognized around the decidual cells in normal pregnancy, very weak or no staining was observed in spontaneous abortion. Northern blot analysis revealed that the decidual expression of messenger ribonucleic acid for the alpha 1(IV) chain was significantly reduced in spontaneous abortion compared to that in normal pregnancy (P < 0.001). These results suggest that type IV collagen might play an important role in the maintenance of pregnancy and that decreased expression of this collagen could be associated with spontaneous abortion.

Abortion, Spontaneous↗

PubMed1996

Alterations in distribution and composition of the extracellular matrix during decidualization of the human endometrium.

The distribution of the extracellular matrix, including type I, III, IV and VI collagens and laminin, and of prolyl hydroxylase was investigated in the human endometrium by an indirect immunofluorescence method with specific monoclonal antibodies. Collagens were also extracted from the endometrial tissues in the proliferative and secretory phases and from the decidual tissues in the first trimester of pregnancy. Immunohistochemical studies demonstrated that interstitial collagens, such as type I, III, and VI collagens, were localized diffusely in the stroma of the endometrium throughout the menstrual cycle, as well as in the decidua. Type IV collagen and laminin were localized exclusively in the basement membrane of the endometrial glands and in the walls of blood vessels during the proliferative and secretory phases. However, strong staining for type IV collagen and laminin was recognized in the pericellular region of endometrial stromal cells in the decidua. Prolyl hydroxylase was localized in the cytoplasm of endometrial stromal cells and endometrial glandular cells during the menstrual cycle. Intense immunostaining for prolyl hydroxylase was observed in the decidual cells. However, immunoreactivity for prolyl hydroxylase in the endometrial glandular cells disappeared during the process of decidualization. The ratio of type III to type I collagen was significantly decreased (P < 0.05) and the ratio of type V to type I collagen was significantly increased (P < 0.01) in the decidua, as compared with ratios in the endometrium during the proliferative phase. The present results suggest that changes in the extracellular matrix may play an important role in implantation, in invasion of trophoblastic cells and in the maintenance of pregnancy.

Basement Membrane↗

PubMed1996

[Electron microscopic observations on the posterior lens capsule after implantation of a silicone intraocular lens in rabbits].

We performed phacoemulsification and aspiration of the crystalline lens and implanted a silicone intraocular lens in the capsular bag in rabbits. The posterior capsules were then observed under transmission electron microscopy 2 or 4 months after the surgery. Lens epithelial cells proliferated between the posterior capsule and the optic portion of the silicone intraocular lens, accompanied with the accumulation of collagenous extracellular matrix.

Animals↗

PubMed1996

Collagen types in healing alkali-burned corneal stroma in rabbits.

We evaluated the change in the type of collagen found during healing in the alkali-burned corneal stroma of rabbits. We estimated the relative proportions of alpha chains in pepsin-solubilized collagen, using sodium dodecylsulfate polyacrylamide gel electrophoresis. Bands of alpha 1(I), alpha 2(I), alpha 1(V), and alpha 1(III) chains stained with Coomassie Blue were separated. The alpha 1(III) and alpha 1(V) chains showed a transient proportional increase in healing corneal stroma in the area exposed to alkali. No significant alterations in collagen alpha chains were detected in peripheral corneal stroma that had not been directly exposed to alkali. Our results suggest that the keratocytes which repopulate the alkali-injured corneal stroma early in healing synthesize a higher proportion of collagen types III and V than type I, and then switch to synthesizing predominantly type I collagen as stromal healing progresses. Collagen types III and V thus appear to be of primary importance in the healing of the corneal stroma.

Animals↗

PubMed1995

Effect of lysyl hydroxylase inhibitor, minoxidil, on ultrastructure and behavior of cultured rabbit subconjunctival fibroblasts.

BACKGROUND: Minoxidil is an inhibitor of lysyl hydroxylase, an enzyme involved in collagen production, and decreases collagen production in vitro. We investigated the in vitro effects of minoxidil on behavior such as proliferation and migration of rabbit subconjunctival fibroblasts (SCFs). The ultrastructural effect of the drug on SCFs was also examined. METHODS: Proliferation of SCFs and closure of the defect produced in monolayer cultures in the presence or absence of minoxidil was studied. The ultrastructure of SCFs treated with minoxidil was also examined. RESULTS: Minoxidil inhibited SCF proliferation and the closure of the defect produced in monolayer cell sheets. Ultrastructural observations revealed extensive areas of irregularly dilated endoplasmic reticulum in cells treated with minoxidil, indicating the accumulation of protein, probably underhydroxylated collagen precursors, in the cisternae of endoplasmic reticulum. CONCLUSIONS: The results indicated that minoxidil attenuated cellular activities of SCFs such as proliferation and migration in vitro. The exact mechanism of the inhibitory effects of minoxidil on these cellular activities is unknown. The findings suggest that the drug might help to prevent bleb scarring after glaucoma filtering surgery.

Animals↗

PubMed1995

Histiocytic haemophagocytosis in a patient with Kawasaki disease: changes in the hypercytokinaemic state.

UNLABELLED: A 32-month-old Japanese boy exhibited haemophagocytic syndrome (HPS) during the recurrent course of Kawasaki disease. Despite repeated gamma-globulin therapy, he developed cytopenia with marked hepatomegaly and evidence of histiocytic haemophagocytosis in the bone marrow. Serum levels of interferon-gamma and tumour necrosis factor, but not of interleukin-1 beta, increased in parallel with his symptoms. No confirmation was obtained of the association of toxic reactions to the used drugs. No coronary lesions remained as sequelae. CONCLUSION: Cytopenia in Kawasaki disease could herald HPS, and the hypercytokinaemia involved in the two febrile syndromes might be of distinct nature.

Child, Preschool↗