Iloprost, Prostaglandin E1, and Papaverine Relax Human Mesenteric Arteries With Similar Potency.

OBJECTIVE: Nonocclusive mesenteric ischemia (NOMI) is accompanied by mesenteric artery spasms that are at least in part due to endothelin system activation. Acute treatment includes intra-arterial infusion of vasodilators such as iloprost, prostaglandin E1 (PGE1), and papaverine. Their effectiveness is not well characterized in human mesenteric arteries. We directly compared their potency to relax isolated human mesenteric arteries. To explore the potential of Rock inhibition to treat mesenteric artery spasms, we tested if endothelin-1 (ET-1)-induced mesenteric artery constrictions depend on rho kinase (Rock). METHODS: Mesenteric artery segments were obtained from patients who underwent elective abdominal surgery. Vasodilator concentration-response curves were recorded from ET-1-preconstricted vessels by small vessel myography. Rock expression was investigated by Western blot and the potency of Rock inhibition to blunt ET-1-induced mesenteric artery constriction was tested. RESULTS: Iloprost, PGE1, and papaverine similarly reduced vascular tone to 20% to 30% of ET-1-induced wall tension. In human mesenteric arteries, logEC50 was significantly less for iloprost than for PGE1 or papaverine. Respective logEC50 values were -7.72 ±â€Š0.08 mol/L, -6.58 ±â€Š0.17 mol/L, and -6.73 ±â€Š0.19 mol/L in 150 µm to 300 µm lumen diameter arteries. These vessels were also more sensitive to iloprost than 500 µm to 1,000 µm lumen diameter arteries (logEC50 -7.29 ±â€Š0.07 mol/L). Rock1 and Rock2 were expressed in human mesenteric arteries but Rock inhibition did not significantly affect ET-1-induced vasoconstrictions. CONCLUSIONS: Iloprost, PGE1, and papaverine have a similar potency to relax mesenteric arteries. Our data suggest that iloprost but not Rock inhibition may be particularly useful to treat ET-1-induced spasms of distal mesenteric arteries.

Quantification of liver proton-density fat fraction in 7.1T preclinical MR systems: Impact of the fitting technique.

PURPOSE: To investigate the feasibility of estimating the proton-density fat fraction (PDFF) using a 7.1T magnetic resonance imaging (MRI) system and to compare the accuracy of liver fat quantification using different fitting approaches. MATERIALS AND METHODS: Fourteen leptin-deficient ob/ob mice and eight intact controls were examined in a 7.1T animal scanner using a 3D six-echo chemical shift-encoded pulse sequence. Confounder-corrected PDFF was calculated using magnitude (magnitude data alone) and combined fitting (complex and magnitude data). Differences between fitting techniques were compared using Bland-Altman analysis. In addition, PDFFs derived with both reconstructions were correlated with histopathological fat content and triglyceride mass fraction using linear regression analysis. RESULTS: The PDFFs determined with the use of both reconstructions correlated very strongly (r = 0.91). However, small mean bias between reconstructions demonstrated divergent results (3.9%; confidence interval [CI] 2.7-5.1%). For both reconstructions, there was linear correlation with histopathology (combined fitting: r = 0.61; magnitude fitting: r = 0.64) and triglyceride content (combined fitting: r = 0.79; magnitude fitting: r = 0.70). CONCLUSION: Liver fat quantification using the PDFF derived from MRI performed at 7.1T is feasible. PDFF has strong correlations with histopathologically determined fat and with triglyceride content. However, small differences between PDFF reconstruction techniques may impair the robustness and reliability of the biomarker at 7.1T. J. Magn. Reson. Imaging 2016;44:1425-1431.

Predictors of technical success and rate of complications of image-guided percutaneous transthoracic lung needle biopsy of pulmonary tumors.

PURPOSE: To investigate predictors of technical success and complications of computed tomography (CT)-guided percutaneous transthoracic needle biopsy of potentially malignant pulmonary tumors. MATERIAL AND METHODS: From 2008 to 2009, technical success and rate of complications of CT-guided percutaneous transthoracic lung needle biopsies of patients with suspicious pulmonary tumors were retrospectively evaluated. The influence on technical success and rate of complications was assessed for intervention-related predictors (lesion diameter, length of biopsy pathway, number of pleural transgressions, and needle size) and patient-related predictors (age, gender, reduced lung function). In addition, technical success and rate of complications were compared between different interventional radiologists. RESULTS: One hundred thirty-eight patients underwent biopsies by 15 interventional radiologists. The overall technical success rate was 84.1% and was significantly different between interventional radiologists (range 25%-100%; p<0.01). Intervention-related and patient-related predictors did not influence the technical success rate. The overall complication rate was 59.4% with 39.1% minor complications and 21.0% major complications. The rate of complications was influenced by lesion diameter and distance of biopsy pathway. Interventional radiologist-related rates of complications were not statistically different. CONCLUSIONS: Technical success of percutaneous, transthoracic lung needle biopsies of pulmonary tumors is probably dependent on the interventional radiologist. In addition, lesion diameter and length of biopsy pathway are predictors of the rate of complications.