| 1. |
- Ewert, Sara, 1974, et al.
(författare)
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Angiotensin II induced contraction of rat and human small intestinal wall musculature in vitro
- 2006
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 188:1, s. 33-40
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Angiotensin II (Ang II) is a well-known activator of smooth muscle in the vasculature but has been little explored with regard to intestinal wall muscular activity. This study investigates pharmacological properties of Ang II and expression of its receptors in small-intestinal smooth muscle from rats and humans. METHODS: Isometric recordings were performed in vitro on small intestinal longitudinal muscle strips. Protein expressions of Ang II typ 1 (AT1R) and typ 2 (AT2R) receptors were assessed by Western blot. RESULTS: Ang II elicited concentration-dependent contractions of rat jejunal and ileal muscle preparations. The concentration-response curve (rat ileum, EC(50): 1.5 +/- 0.9 x 10(-8) M) was shifted to the right by the AT1R receptor antagonist losartan (10(-7) M) but was unaffected by the AT2R antagonist PD123319 (10(-7) M) as well as by the adrenolytic guanethidine (3 x 10(-6) M) and the anticholinergic atropine (10(-6) M). Human duodenal, jejunal and ileal longitudinal muscle preparations all contracted concentration-dependently in response to Ang II. The concentration-response curve (human jejunum, EC(50): 1.5 +/- 0.8 x 10(-8) M) was shifted to the right by losartan (10(-7) M) but was unaffected by PD123319 (10(-7) M). Both AT1R and AT2R were detected in all segments of the rat small intestinal wall musculature, whereas only AT1R was readily detectable in the human samples. CONCLUSION: Ang II elicits contractions of small-intestinal longitudinal muscle preparations from the small intestine of rats and man. The pharmacological pattern and protein expression analyses indicate mediation via the AT1R.
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| 2. |
- Ewert, Sara, 1974, et al.
(författare)
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Dynamic expression of the angiotensin II type 2 receptor and duodenal mucosal alkaline secretion in the Sprague-Dawley rat
- 2006
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Ingår i: Experimental Physiology. - : Wiley. - 0958-0670. ; 91:1, s. 191-199
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Tidskriftsartikel (refereegranskat)abstract
- Activation of angiotensin II type 2 receptors (AT2R) has been shown to stimulate duodenal mucosal alkaline secretion (DMAS) in Sprague-Dawley rats (S-D). This finding could not be confirmed in another line of S-D, and the present study investigates whether the level of AT2R expression determines the response to the AT2R agonist CGP42112A. DMAS was measured in anaesthetized rats using in situ pH-stat titration. Real-time PCR and Western blot were used to assess AT1R and AT2R RNA and protein expression, respectively. CGP42112A (0.1 microg kg(-1)min(-1) I.V.) elicited a 45% net increase in DMAS in the previous S-D line studied, whereas no change occurred in the new S-D line. Luminal administration of prostaglandin E2 (10(-5) M) increased DMAS similarly in both S-D lines. AT2R protein expression was significantly higher in tissue from the previous line compared to the new line. Individual AT1R to AT2R ratios (RNA and protein) were significantly higher in the new line compared to the previous S-D line. In the new S-D line intravenous infusion of angiotensin II (Ang II; 10 microg kg(-1) h(-1)) over 120 min significantly lowered the duodenal AT1aR to AT2R RNA ratio. Prolonged Ang II infusion over 240 min increased AT2R protein expression and evoked a 42% stimulatory response in DMAS to CGP42112A. The level of local AT2R expression determines the effect of the AT2R agonist CGP42112A on rat duodenal mucosal alkaline secretion. AT2R expression should be confirmed before interpreting the experimental effects of pharmacological interferences with this receptor.
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| 3. |
- Spak, Emma, 1977, et al.
(författare)
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Angiotensin II receptor expression following intestinal transplantation in mice.
- 2006
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Ingår i: The Journal of surgical research. - : Elsevier BV. - 0022-4804. ; 135:1, s. 144-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To further improve the success rate of intestinal transplantation there is a need to find early appearing indicators of rejection. The specific aim of this study was to compare Angiotensin (Ang) II type 1 receptor and Ang II type 2 receptor expression in relation to histological signs of rejection. METHODS: Mice of the C57BL6 strain with syngeneic intestinal grafts were compared to mice subjected to allogeneic intestinal transplantation with BalbC strain as donors. Local expression of Ang II type 1 and 2 receptor was evaluated using rt-PCR and Western blot and compared to histological picture in grafts and native intestine. RESULTS: The Ang II type 2 receptor protein expression was markedly up-regulated in the allogeneically transplanted graft from day 1 postoperatively. Histological signs of rejection were not seen until day 6. CONCLUSION: Intestinal allograft transplantation in mice is associated with a marked up-regulation of the Ang II type 2 receptor. However, the detailed role of the renin-angiotensin system in the immune rejection following intestinal transplantation remains to be clarified.
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| 4. |
- Wählby, Carolina, 1974-, et al.
(författare)
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Finding cells, finding molecules, finding patterns
- 2006
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Ingår i: Advances in Data Mining. ; , s. 15-24
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Konferensbidrag (refereegranskat)abstract
- Many modern molecular labeling techniques result in bright point signals. Signals from molecules that are detected directly inside a cell can be captured by fluorescence microscopy. Signals representing different types of molecules may be randomly distributed in the cells or show systematic patterns indicating that the corresponding molecules have specific, non-random localizations and functions in the cell. Assessing this information requires high speed robust image segmentation followed by signal detection, and finally pattern analysis. We present and discuss this type of methods and show an example of how the distribution of different variants of mitochondrial DNA can be analyzed.
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