ZnO nanopillar arrays with high aspect ratios, such as the one shown in the figure, are fabricated from aqueous solutions at low temperatures using a polymer mold. The shape and dimensions of the ...nanopillars can be tuned by appropriately patterning the polymer mold. A hexagonal ZnO nanopillar array shows photonic bandgaps at visible wavelengths, as predicted by photonic band structure calculations.
Expression of heat shock protein 70, induced by an antiulcer drug, provides protection against gastric ulcers. However, the mechanisms responsible for this protection are not known. The expression in ...ulcer-resistant, spontaneously hypertensive rats was 2.8-fold higher than in normotensive rats. One hour after restraint and water immersion stress, strong nuclear immunoreactivity was observed in nuclei of surface epithelial cells at the crest of gastric mucosal folds, the first site of ulceration, only in spontaneously hypertensive rats. Heat shock cognate protein 70, which is expressed in mucus-secreting cells, was not overexpressed in spontaneously hypertensive rats. Heat shock protein 70 expression was attenuated by chemical sympathectomy, which also resulted in abolition of the increase of mucosal blood flow and aggravation of ulcers. Our results indicate that overexpression of heat shock protein 70 in the stomach seems to protect against gastric ulcers through its cytoprotective effects on gastric mucosa by increasing mucosal blood flow.
Ets-1 is a transcription factor regulating the expression of matrix-degrading proteinases and is believed to play a critical role in cell migration and tumor invasion. The aim of this study is to ...investigate the direct induction of ets-1 with consequential upregulation of collagenase-1 (MMP-1) by cell adhesion to extracellular matrix and to identify intracellular signal transduction pathways involved in ets-1 induction in cultured endothelial cells. The expressions of ets-1 mRNA and protein as well as MMP-1 protein were induced by cell adhesion to type I collagen and antisense ets-1 oligonucleotides impaired that MMP-1 expression. In addition, protein tyrosine kinase (PTK) and protein kinase C (PKC) inhibitors abrogated their induction, showing the suppression of focal adhesion kinase phosphorylation. These results suggest that ets-1 induced by cell adhesion to extracellular matrix directly upregulates MMP-1 expression via PTK and PKC activation in cultured endothelial cells.
To evaluate the effect of fermented milk kefir on X-ray-induced apoptosis in the colon of rats, we examined the apoptotic index, the mean number of apoptotic cells detected by H&E staining per crypt ...in the colon, in control rats and kefir-pretreated rats drinking kefir for 12 days before irradiation. Apoptotic cells were confirmed by TUNEL staining, and active caspase-3 expression was studied by immunohistochemistry. The cell position of apoptotic cells and active caspase-3 positive cells were examined. The apoptotic index of kefirtreated rats was significantly (p < 0.05) decreased 2 h after 1 Gy irradiation in comparison with control rats at crypt cell positions 1-3, 5-7, 13, and 15. Active caspase-3 expression in the kefir-treated rats was also significantly (p < 0.05) reduced in comparison with control rats 2 h after 1 Gy irradiation at crypt cell positions 1-4, 13, and 15. This study indicated that kefir protects colonic crypt cells against radiation-induced apoptosis, which was most pronounced in the stem cell region of the crypt. The antiapoptotic effect of fermented milk kefir was due to the inhibition of caspase-3 activation.
Polaprezinc, an anti-ulcer drug, is a chelate compound consisting of zinc and L-carnosine. Polaprezinc has been shown to prevent gastric mucosal injury. The anti ulcer effects of polaprezinc have ...been ascribed to its antioxidative property. The effect of polaprezinc on ionizing radiation-induced apoptosis was studied in the jejunal epithelial crypt cells of rats. Seven-to eight week-old Wistar rats, which were treated with 100 mg/kg of polaprezinc orally 1h before irradiation or 2% carboxymethyl cellulose sodium in controls, were exposed to whole body X-ray irradiation at 2 Gy. The number of apoptotic cells per jejunum crypt was counted in haematoxylin and eosin stained sections at 0.6 h after irradiation. TUNEL positive cells and immunopositive cells for active caspase-3 per crypt were also counted. Accumulation of p53, p21WAF1/CIP1 and Bax expression in the jejunum after irradiation were examined by Western blot analyses. Polaprezinc treatment given prior to radiation resulted in a significant reduction in numbers of apoptotic cells, TUNEL positive cells and active caspase-3 immunopositive cells in jejunal crypt cells. Polaprezinc treatment resulted in decreases of p53 accumulation, p21WAF1/CIP1 and Bax expression after irradiation. Polaprezinc has a protective effect against ionizing radiation induced apoptosis in rat jejunal crypt cells.
Matsuu, M., Shichijo, K., Ikeda, Y., Ito, M., Naito, S., Okaichi, K., Nakashima, M., Nakayama, T. and Sekine, I. Sympathetic Hyperfunction Causes Increased Sensitivity of the Autonomic Nervous System ...to Whole-Body X Irradiation. Radiat. Res. 163, 137–143 (2005). Although the etiology of radiation sickness is still unknown, disturbance of the autonomic nervous system is suggested to be a factor. This study was designed to compare the radiosensitivity of spontaneously hypertensive rats possessing sympathetic hyperfunction and control Wistar-Kyoto rats, and to analyze the effects of radiation on the autonomic nervous system in both strains. After a 7.5-Gy dose of whole-body X irradiation, the blood pressure decreased significantly at 8 h and 2 days in the spontaneously hypertensive rats, but not in the Wistar-Kyoto rats. Epinephrine levels in the adrenal gland of spontaneously hypertensive rats decreased at 4, 8 and 24 h, unlike the Wistar-Kyoto rats. Radiation evoked a stronger increase in norepinephrine in the jejunum and colon of spontaneously hypertensive rats than in Wistar-Kyoto rats. Acethylcholine levels in the jejunum of spontaneously hypertensive rats decreased, in contrast to the increase in Wistar-Kyoto rats within 24 h after irradiation. The survival rate of spontaneously hypertensive rats was lower than that of Wistar-Kyoto rats and weight loss, appetite loss and morphological changes in the jejunum were greater in spontaneously hypertensive rats than in Wistar-Kyoto rats after irradiation. These results indicated that X irradiation caused greater activities in autonomic nervous function and severe radiation injury in spontaneously hypertensive rats. Sympathetic hyperfunction may be associated with a higher sensitivity to radiation, including radiation injury and radiation sickness.
Angiogenesis is an important process in tissue development and wound healing. The Tie-2 receptor tyrosine kinases and ligands, angiopoietin (Ang)-1 and -2 have been postulated to play key roles in ...vascular development. The purpose of this study was to evaluate the expression of Tie-2 and Ang-1 and -2 in an acetic acid-induced gastric ulcer healing process in rats.
Gastric specimens were obtained at 0 (control), 1, 3, 5, 7, and 14 days after ulcer induction for reverse transcription polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical analysis.
Expression of Tie-2 and Ang-1 and -2 mRNAs was detected in normal gastric tissue and ulcerative tissues by RT-PCR. Western blot analysis revealed that Tie-2 expression reached a maximum on the third to fifth days. Expression of Ang-1 and -2 peaked on the first day. Ang-1 expression gradually became weaker in 2 weeks, whereas Ang-2 expression returned to normal in a few days. Immunohistochemically, Tie-2 was expressed constitutively in the endothelial cells of pre-existing vessels of the gastric wall, and Tie-2 expression was increased in the new capillaries of the ulcer base.
These findings suggest that Tie-2 and Ang-1 and -2 play an important role in angiogenesis in the early phase of ulcer healing.
The purpose of this study was to evaluate the healing effect of interleukin-11 (IL-11) on acetic acid-induced gastric ulcer in rats. Gastric ulcers were induced in male Wistar rats by applying acetic ...acid to the fundus of the stomach. Recombinant human interleukin-11 (rhIL-11 100 μg/kg/twice daily, subcutaneously) was administered starting on the 2nd day before ulcer induction up through the 7th day after ulcer induction. Control rats were injected with bovine serum albumin. At 12 hours and 7 days after ulcer induction, the animals were sacrificed, and the ulcer index, proliferating cell nuclear antigen (PCNA) expression, and IL-11α receptor expression in the gastric tissues were studied. The ulcer index of the rhIL-11-treated rats was significantly lower than that of the control rats at the 7th day. The expression of PCNA as evaluated by Western blotting and immunohistochemistry, was enhanced in both the mucosal proliferative zone and proper muscle layer of the rhIL-11-treated rats in comparison with that in the control rats. IL-11α receptor expression was observed in the mucosal neck cells of the rhIL-11-treated rats and control rats. These findings suggest that IL-11 accelerates ulcer healing by inducing the proliferation of mucosal and muscular cells.
To investigate Tie-2 expression during the repair of acetic acid-induced gastric ulcers in rats treated with recombinant human IL-11 (rhIL-11) and in untreated control animals.
Gastric ulcers were ...induced in male Wistar rats by applying acetic acid to the fundus of the stomach. RhIL-11 (100 microg/kg twice daily, subcutaneously) was administered from two days before ulcer induction and continued for five days after the induction. Control rats received bovine serum albumin. Gastric specimens were collected at 3 and 5 days after the induction of ulcer for immunohistochemical observation, Western blotting, and reverse transcription polymerase chain reaction (RT-PCR).
Immunohistochemical and Western blot analysis demonstrated that Tie-2 expression was enhanced in the rhIL-11-treated rats compared with the control animals at both intervals.
These findings suggested that IL-11 could accelerate ulcer healing, in part, by up-regulating Tie-2 expression and promoting angiogenesis.
Radiotherapy for malignant pelvic disease is often followed by acute radiation colitis (ARC). It has been reported that sucralfate treatment has a protective effect against ARC, though the mechanisms ...of action are unknown. The effects of sucralfate on X-ray radiation-induced apoptosis was studied at 4 Gy in the colonic crypt cells of rats. Sucralfate enemas given prior to radiation resulted in the following： (1) reduction in number of apoptotic colonic crypt cells; (2) reduction in number of caspase-3 positive cells; (3) decreases in p53 accumulation and p21 expression; (4) decreases of Bax/Bcl-2 ratio. The protective effects of sucralfate against ARC may be partially due to the suppression of radiation-induced apoptosis by way of p53 in the colon and the protection of the colonic epithelial stem cell region.
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