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- Gronros, J, et al.
(författare)
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Arginase inhibition restores in vivo coronary microvascular function in type 2 diabetic rats
- 2011
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Ingår i: American journal of physiology. Heart and circulatory physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 300:4, s. H1174-H1181
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Tidskriftsartikel (refereegranskat)abstract
- Nitric oxide (NO) is crucial for maintaining normal endothelial function and vascular integrity. Increased arginase activity in diabetes might compete with NO synthase (NOS) for their common substrate arginine, resulting in diminished production of NO. The aim of this study was to evaluate coronary microvascular function in type 2 diabetic Goto-Kakizaki (GK) rats using in vivo coronary flow velocity reserve (CFVR) and the effect of arginase inhibition to restore vascular function. Different groups of GK and Wistar rats were given vehicle, the arginase inhibitor Nω-hydroxy-nor-l-arginine (nor-NOHA), l-arginine, and the NOS inhibitor NG-monomethyl -l-arginine (l-NMMA). GK rats had impaired CFVR compared with Wistar rats (1.31 ± 0.09 vs. 1.87 ± 0.05, P < 0.001). CFVR was restored by nor-NOHA treatment compared with vehicle in GK rats (1.71 ± 0.13 vs. 1.23 ± 0.12, P < 0.05) but remained unchanged in Wistar rats (1.88 ± 0.10 vs. 1.79 ± 0.16). The beneficial effect of nor-NOHA in GK rats was abolished after NOS inhibition. CFVR was not affected by arginine compared with vehicle. Arginase II expression was increased in the aorta and myocardium from GK rats compared with Wistar rats. Citrulline-to-ornithine and citrulline-to-arginine ratios measured in plasma increased significantly more in GK rats than in Wistar rats after nor-NOHA treatment, suggesting a shift of arginine utilization from arginase to NOS. In conclusion, coronary artery microvascular function is impaired in the type 2 diabetic GK rat. Treatment with nor-NOHA restores the microvascular function by a mechanism related to increased utilization of arginine by NOS and increased NO availability.
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- Nicholls, M, et al.
(författare)
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European Perspectives in Cardiology
- 2013
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Ingår i: CIRCULATION. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 128:23, s. F133-F138
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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- Sorensson, P., et al.
(författare)
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Assessment of myocardium at risk with contrast enhanced steady-state free precession cine cardiovascular magnetic resonance compared to single-photon emission computed tomography
- 2010
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Ingår i: Journal of Cardiovascular Magnetic Resonance. - : Springer Science and Business Media LLC. - 1097-6647 .- 1532-429X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Final infarct size following coronary occlusion is determined by the duration of ischemia, the size of myocardium at risk (MaR) and reperfusion injury. The reference method for determining MaR, single-photon emission computed tomography (SPECT) before reperfusion, is impractical in an acute setting. The aim of the present study was to evaluate whether MaR can be determined from the contrast enhanced myocardium using steady-state free precession (SSFP) cine cardiovascular magnetic resonance (CMR) performed one week after the acute event in ST-elevation myocardial infarction (STEMI) patients with total coronary occlusion. RESULTS: Sixteen patients with STEMI (age 64 +/- 8 years) received intravenous 99 m-Tc immediately before primary percutaneous coronary intervention. SPECT was performed within four hours. MaR was defined as the non-perfused myocardial volume derived with SPECT. CMR was performed 7.8 +/- 1.2 days after the myocardial infarction using a protocol in which the contrast agent was administered before acquisition of short-axis SSFP cines. MaR was evaluated as the contrast enhanced myocardial volume in the cines by two blinded observers. MaR determined from the enhanced region on cine CMR correlated significantly with that derived with SPECT (r2 = 0.78, p < 0.001). The difference in MaR determined by CMR and SPECT was 0.5 +/- 5.1% (mean +/- SD). The interobserver variability of contrast enhanced cine SSFP measurements was 1.6 +/- 3.7% (mean +/- SD) of the left ventricle wall volume. CONCLUSIONS: Contrast enhanced SSFP cine CMR performed one week after acute infarction accurately depicts MaR prior to reperfusion in STEMI patients with total occlusion undergoing primary PCI. This suggests that a single CMR examination might be performed for determination of MaR and infarct size.
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- Sorensson, P., et al.
(författare)
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Effect of postconditioning on infarct size in patients with ST elevation myocardial infarction
- 2010
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Ingår i: Heart. - : BMJ. - 1355-6037 .- 1468-201X. ; 96:21, s. 1710-5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Small studies suggest that postconditioning reperfusion interrupted by brief repetitive cycles of reocclusions, may protect the myocardium in the clinical setting. OBJECTIVE: To test the hypothesis that postconditioning limits infarct size in relation to the area at risk in patients with ST elevation myocardial infarction (STEMI). METHODS: 76 patients (aged 37-87 years) eligible for primary percutaneous coronary intervention due to STEMI were randomised to standard percutaneous coronary intervention (n = 38) or postconditioning, consisting of four cycles of 60 s reperfusion and 60 s of reocclusion before permanent reperfusion (n = 38). RESULTS: The area at risk was determined from angiographic abnormally contracting segments. Infarct size was quantified from delayed enhancement MRI on days 6-9. Infarct size, expressed in relation to the area at risk, did not differ between the control group (44%; 30, 56) (median and quartiles) and the post-conditioned group (47%; 23, 63). The slope of the regression lines relating infarct size to the area at risk differed between the two groups. Infarct size was significantly (p = 0.001) reduced by postconditioning in patients with large areas at risk. The area under the curve and peak troponin T release and CKMB during 48 h did not differ between patients in the control and postconditioning groups. CONCLUSIONS: This prospective, randomised trial suggests that postconditioning does not reduce infarct size in patients with STEMI in the overall study group. The data indicate that postconditioning may be of value in patients with large areas at risk. Clinical trial registration information Karolinska Clinical Trial Registration (http://www.kctr.se). Unique identifier: CT20080014.
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