Origin of the apical transcytic membrane system in jejunal absorptive cells of neonates.

We investigated the origin of the apical transcytic membrane system in jejunal absorptive cells of neonatal rats using light, electron, and immunofluorescence microscopy. In rats just after birth, intraluminally injected horseradish peroxidase (HRP), used as a macromolecular tracer, was observed only in the apical endocytic membrane system including the lysosomes, of jejunal absorptive cells in vivo. No tracer, however, was found in the intercellular space between the jejunal absorptive cells and the submucosa.

Expressions of the multidrug resistance-related proteins in the rat olfactory epithelium: a possible role in the phase III xenobiotic metabolizing function.

The xenobiotic metabolizing system is considered to play important roles in the olfaction by the chemical homeostasis. Several phase I and phase II xenobiotic metabolizing enzymes are expressed in the olfactory epithelium in vertebrates. Multidrug resistance-related proteins (MRPs) are the phase III xenobiotic metabolizing pumps that eliminate some conjugated ligands from cells.

Antioxidant enzyme immunoreactivity in rat von Ebner gland after nickel treatment.

Our study was designed to clarify the role of antioxidant enzymes in the rat von Ebner gland during acute nickel toxicity. After treatment with nickel acetate, we monitored ultrastructural alterations in acinar and ductal cells, immunohistochemical staining for glutathione peroxidase (GPx) and glutathione S-transferases (GST mu and GST pi), and immunoreactivity for malondialdehyde (MDA). Immunoreactivity for MDA was present only in the acinar cells, and it was enhanced at 3 h after Ni treatment.

Molecular morphology of the digestive tract; macromolecules and food allergens are transferred intact across the intestinal absorptive cells during the neonatal-suckling period.

Food allergies represent an important medical problem throughout the developed world. The epithelium of the digestive tract is an important area of contact between the organism and its external environment. Accordingly, we must reconsider the transport of intestinal transepithelial macromolecules, including food allergens, in vivo.

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.

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.

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.

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.

[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.

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.

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.

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.

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.