Biomedical subjects

Sunao Fujimoto

Publications and source records attributed to Sunao Fujimoto.

9 recordsLinked to original sources

PubMed2005

Relationship between glucose transporter and changes in the absorptive system in small intestinal absorptive cells during the weaning process.

In the present study, we investigated the changes in the localization of the glucose transporter GLUT2 and the fructose transporter GLUT5 in small intestinal absorptive cells during postnatal development, especially during the weaning period, using immunohistochemistry and confocal laser scanning microscopy. In the jejunum, GLUT2 was observed within the apical and basolateral membrane domain of absorptive cells, especially in the middle part of the villi. In the suckling rat ileum, GLUT2 was found within the apical and basolateral membrane domain of absorptive cells, but after 18 or 19 days after birth, GLUT2 was found mainly within the apical membrane domain. GLUT5 was observed within the apical membrane domain of absorptive cells in the suckling rat jejunum. In the 18- or 19-day-old rat jejunum, GLUT5 was localized within the apical and basolateral membrane domain of absorptive cells in the lower part of the villi, but after weaning, GLUT5 was found within the apical and basolateral membrane domain of absorptive cells throughout the entire villi. In the suckling rat ileum, there was little GLUT5 in the absorptive cells. In the 18- or 19-day-old rat ileum, GLUT5 was localized within the apical membrane domain of absorptive cells in the lower part of the villi, but after weaning, GLUT5 was observed mainly within the apical membrane domain of absorptive cells throughout the entire villi. These results suggest that the localization of glucose transporters corresponds with a shift from neonatal-suckling to weaned absorptive cells during postnatal development.

Absorption↗

PubMed2005

Increased immunoreactivities against endothelin-converting enzyme-1 and monocyte chemotactic protein-1 in hepatic stellate cells of rat fibrous liver induced by thioacetamide.

The progression of rat liver fibrosis induced by intraperitoneal administration of thioacetamide (TAA) was evaluated by immunocytochemistry using anti-alpha-smooth muscle actin (alpha-SMA), antiendothelin-converting enzyme (ECE)-1, and anti-monocyte chemotactic protein (MCP)-1 antibodies. The fibrous septal spaces gradually increased after administration of TAA, and pseudolobules were established in the 7-week TAA-treated groups. Immunoreactivities against alpha-SMA were not detected in hepatic stellate cells (HSCs) of the control group without TAA treatment, although they were observed in the HSCs around the fibrous septal spaces in all TAA-treated groups, indicating that activation of HSCs occurs during the establishment of pseudolobules. Immunoreactivities against ECE-1 and MCP-1 were seen in such HSCs of the TAA-treated groups, but few or no immunoreactivities were detected in the HSCs of the control group. The most significant increase in the ECE-1 immunoreactivities was detected in the 1-week TAA-treated group, whereas that in MCP-1 was observed in the 7-week TAA-treated group. The present immunocytochemistry indicated a difference in the accelerated expression period between immunoreactivities against ECE-1 and MCP-1 in the HSCs during the progression of TAA-induced liver fibrosis, suggesting that ECE-1 is involved in the early phase of liver fibrosis and that MCP-1 plays a role during the later phase.

Animals↗

PubMed2004

The enhancement of preproendothelin-1 synthesis and the acceleration of endothelin-1 processing in the acute hypoxic rat aorta.

Wistar rats were deeply anesthetized and perfused by Hanks' solution bubbled with either 95% air and 5% CO2 (normoxic group) or 95% N2 and 5% CO2 (hypoxic group) from the thoracic aorta for 30 minutes. The isolated abdominal aortas were used for electron microscopy, immunocytochemistry of endothelin-1 (ET-1) and endothelin-converting enzyme-1 (ECE-1), and in situ hybridization of preproendothelin-1 mRNA. A remarkable increase in the number of Weibel-Palade bodies, storage sites of ET-1 and ECE-1, occurred in the hypoxic group when compared with the normoxic group. Immunoreactivities for ET-1 and ECE-1, and signals for preproendothelin-1 mRNA were seen along the endothelia of both groups, but the intensities were significantly elevated in the hypoxic group. The increase in the number of ECE-1 immunoreactive gold particles was noticed in Weibel-Palade bodies in the hypoxic group. These findings indicate the enhancement of preproendothelin-1 synthesis in the rat aortic endothelial cells and the acceleration of ET-1 processing in Weibel-Palade bodies of such cells in an acute hypoxic condition.

Acute Disease↗

PubMed2004

Detection of a smaller, 32-kDa 8-oxoguanine DNA glycosylase 1 in 3'-methyl-4-dimethylamino-azobenzene-treated mouse liver.

We previously reported that 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) increased the 8-hydroxyguanine (8-OH-Gua) content in nuclear DNA and the base excision repair activity in mouse liver. However, to understand the mechanism of 3'-MeDAB carcinogenesis, a further investigation of the 8-OH-Gua repair systems was necessary. In this report, we examined the expression of the repair enzyme, 8-oxoguanine DNA glycosylase 1 (OGG1), in 3'-MeDAB-treated mouse liver. We prepared four kinds of anti-peptide polyclonal antibodies raised against mouse OGG1 (mOGG1). The sequences used as epitopes were designed from positions located close to the N-terminus, the nuclear localization signal (NLS), and the regions containing Lys(249) and Asp(267), which are involved in the catalytic mechanisms of mOGG1 (glycosylase and lyase, respectively). Immunoblotting, using all four antibodies, revealed a 32-kDa protein (mOGG1-32) in addition to the 38-kDa mOGG1 in the 3'-MeDAB-treated mouse liver. Moreover, immunostaining with mOGG1 antibody yielded strong, positive signals in the 3'-MeDAB-treated mouse liver nuclei. However, we could not detect any difference in the Ogg1 mRNA expression pattern. Although the function of mOGG1-32 remains unclear, these findings suggest that 3'-MeDAB may alter the function of the DNA repair protein, and this action may be related to 3'-MeDAB carcinogenesis.

Animals↗

PubMed2003

[Vasculogenesis and angiogenesis].

Vasculogenesis is defined as a neovascularization manner by which endothelial progenitor cells are successively incorporated into the growing capillaries, whereas angiogenesis is another neovascularization manner which includes mitotic proliferations of endothelial cells of the preexisting capillaries and their migration to the vascular tips forming so called "vascular sprouts" or "endothelial buds". Although angiogenesis had been considered to be more prevalent during organogenesis as well as during a wound healing process of adult mammals, recent findings that endothelial progenitor cells were isolated from human peripheral blood and incorporated into sites of active neovascularization have led many researchers to recognize the significance of vasculogenesis in a phenomenon of neovascularization. This paper mainly deals with the history of morphological approaches to clarify the crucial roles of vasculogenesis during organogenesis and a wound healing process.

Animals↗

PubMed2002

Enhanced immunocytochemical expression of antioxidant enzymes in rat submandibular gland after normobaric oxygenation.

In order to clarify the role of antioxidant enzymes in the male rat submandibular gland against short-term normobaric oxygenation, we performed immunocytochemical staining of manganese-containing superoxide dismutase (Mn-SOD), copper- and zinc-containing SOD (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase, and glutathione S-transferases (GST alpha, GST mu, and GST pi) between days 1 and 7 after normobaric oxygenation. Ultrastructural alterations and immunoreactivities for malondialdehyde (MDA), a lipid peroxidation-related molecule, of the acinar and ductal cells after the oxygenation were also investigated. Immunoreactivity for MDA was exhibited in the acinar cells throughout the experiment. On the other hand, immunoreactivity for the SODs, CAT, and GSTs was not altered, when compared to that of controls, but was significantly elevated in the granular, striated, and excretory ductal cells. Since an increase of lipid peroxidation as indicated by enhanced immunoreactivity for MDA was detected in the acinar and intercalated ductal cells, the results indicate that the enhanced antioxidant enzymes in the granular, striated, and excretory ductal cells play a crucial role in the self-defense system of the male rat submandibular gland against normobaric oxygenation.

Animals↗

PubMed2002

Enhancement of immunoreactivity for endothelin-1 and endothelin-converting enzyme-1 in the cadmium-treated rat thoracic aorta.

Male rats received daily intraperitoneal injections of cadmium sulfate (2.0 mg/kg) for 3, 6, and 8 days (cadmium-treated groups) or physiological saline for 8 days (control group). The thoracic aortae from both groups were used for electron microscopy and immunocytochemistry for big endothelin (ET)-1, ET-1 and ET-converting enzyme (ECE)-1, and the blood plasma and homogenized thoracic aortae were prepared for assays of big ET-1 and ET-1 concentrations. A remarkable increase in the number of Weibel-Palade (WP) bodies, enhanced immunoreactivities for ET-1 and ECE-1 along the endothelium, and elevated concentrations of ET-1 in the blood plasma as well as in homogenized thoracic aortae were observed in the cadmium-treated groups. However, immunoreactivity for big ET-1 and the plasma and aortic tissue concentrations of big ET-1 did not show any significant changes between the control and cadmium-treated groups. By immunoelectron microscopy, immunoreactivities for ET-1 and ECE-1 were much more pronounced in the increased WP bodies. Since WP bodies are involved in the extracellular release of ET-1 in the manner of a regulated pathway, these findings indicate that cadmium administration induces the enhanced release of ET-1, which is actively processed by ECE-1 in the WP bodies.

Animals↗

PubMed2000

Expression of profilin, an actin-binding protein, in rat experimental glomerulonephritis and its upregulation by basic fibroblast growth factor in cultured rat mesangial cells.

Profilin binds to actin monomer to regulate actin polymerization, and to phosphatidylinositol 4,5-bisphosphate to inhibit hydrolysis by phospholipase Cgamma1. This study investigated the expression of profilin in rat anti-Thy-1.1 mesangial proliferative glomerulonephritis (GN) and examined the effect of growth factors on its expression in cultured rat mesangial cells. Profilin mRNA was constitutively expressed in isolated glomeruli of untreated rats. However, in glomeruli of anti-Thy-1.1 GN rats, its expression was upregulated beginning on day 1, reaching a peak level on day 4 (3.9-fold versus control glomeruli), and decreased on day 14, as determined by competitive reverse transcription-PCR. Increased expression of profilin protein was confirmed using immunoblotting and immunohistochemistry. Immunoelectron microscopy revealed the presence of profilin in plasma membrane and the rough endoplasmic reticulum of mesangial cells, indicating that profilin was produced in mesangial cells. In cultured rat mesangial cells, expression of profilin mRNA and protein was upregulated by basic fibroblast growth factor but not by platelet-derived growth factor or transforming growth factor-beta. Suppression of profilin expression using an antisense oligonucleotide against profilin inhibited [3H]thymidine uptake. These findings indicated the involvement of profilin in anti-Thy-1.1 GN and suggest that the upregulation of profilin might be involved in the progression of anti-Thy-1.1 GN possibly by affecting cell growth.

Actins↗

PubMed1999

Effects of endothelin-1 on vasoactivity and its synthesis, storage, and acting sites in the rat superior mesenteric vasculature: an ultrastructural and immunocytochemical study.

Vasoactivity after treatment with endothelin (ET)-1 and immunoreactivity for ET-1 and its receptors were investigated in the rat superior mesenteric vasculature (SMV). By measurements of corrosion cast images of the SMVs, it was seen that ET-1 induces remarkable vasocontraction of the distal arterial branches, consisting of small arteries and arterioles, and localized vasoconstriction throughout the venous branches which possess localized medial thickenings. Immunoreactivity for ET-1 was preferentially seen along the endothelia of the proximal arterial branches. Cisterns of the rough endoplasmic reticulum and Weibel-Palade (WP) bodies of the endothelial cells were immunoreacted. Immunoreactivity for the ETa receptor was preferentially seen on the media of the distal arterial branches. These findings indicate that endothelial cells of the proximal arterial branches synthesize ET-1 and store it in the WP bodies. Because WP bodies are involved in the release of ET-1, this suggests that this endogenous ET-1, which is released from the proximal arterial branches, may be involved in the regulation of blood flow through the distal arterial branches by mediation of the ETa receptor. In addition, it seems likely that ET-1-induced vasoconstriction of the venous branches may act to impel the portal blood flow.

Journal Article↗