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Journal of vascular and interventional radiology: JVIR 04/2012; 23(4):574-5; author reply 575-6. · 1.81 Impact Factor
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ABSTRACT: Growing crops for bioenergy or biofuels is increasingly viewed as conflicting with food production. However, energy use continues to rise and food production requires fuel inputs, which have increased with intensification. Focussing on the question of food or fuel is thus not helpful. The bigger, more pertinent, challenge is how the increasing demands for food and energy can be met in the future, particularly when water and land availability will be limited. Energy crop production systems differ greatly in environmental impact. The use of high-input food crops for liquid transport fuels (first-generation biofuels) needs to be phased out and replaced by the use of crop residues and low-input perennial crops (second/advanced-generation biofuels) with multiple environmental benefits. More research effort is needed to improve yields of biomass crops grown on lower grade land, and maximum value should be extracted through the exploitation of co-products and integrated biorefinery systems. Policy must continually emphasize the changes needed and tie incentives to improved greenhous gas reduction and environmental performance of biofuels.
Journal of Experimental Botany 04/2011; 62(10):3263-71. · 5.36 Impact Factor
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ABSTRACT: To evaluate safety and efficacy of uterine artery embolization using narrow-size-range polyphosphazene-coated hydrogel microspheres (Embozene, CeloNova Biosciences, Newnan, GA).
Between May 2006 and September 2008, a total of 121 consecutive patients (mean ± SD age 42.1 ± 5.4 years, range 30.5-51.5 years) were enrolled onto this single-center study. The primary study endpoint was safety as assessed by the society of interventional radiology (SIR) classification. The secondary endpoint was efficacy, which was based on a 1-year magnetic resonance imaging study and relief of symptoms documented by the Medical Outcomes Study 36-Item Short-Form Health Survey questionnaire over a 2-year interval.
The mean ± SD diameter of the dominant fibroid was 6.4 ± 2.6 (range, 2.9-13.9) cm and the mean volume 137.2 ± 245.1 (range, 5.3-1184) ml. Most patients had multiple fibroids with 11% more than 10. A total of 240 of 242 interventions were completed as planned, a technical success rate of 99.2%. According to the SIR classification, one type A, eight type C, and one type D complication occurred. Total devascularization was noted in 96% (116 of 121) of dominant fibroids. Volume decrease was 4% at 2 weeks, 52% (P < 0.001) at 3 months, 78% (P < 0.001) at 6 months, and 91% at 12 months (P < 0.001). The latter difference was statistically significant (P = 0.007). A total of 92% had improved hypermenorrhea at 1 year and 94% at 2 years. Dysmenorrhea was improved in 96% at 1 year and in 95% at 2 years. The overall health status score was 60.4 ± 26.2 points at baseline and 96.9 ± 3.8 after 1 year (P = 0.0019).
Uterine artery embolization with Embozene microspheres is a safe procedure. Its efficacy is demonstrated by high fibroid devascularization and volume reduction rates and significant improvements of clinical symptoms and quality-of-life scores during follow-up.
CardioVascular and Interventional Radiology 10/2010; 34(2):295-305. · 2.09 Impact Factor
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ABSTRACT: Paclitaxel is an antiproliferative agent in drug-eluting stents with largely unknown tissue interaction. Toxicity might result from overdosage and/or accumulation. Part 1 of this two-step study investigated how paclitaxel uptake depends on dose density, coronary drug transfer kinetics, and elution efficacy.
With cobalt chromium stents and Polyzene-F nanoscale coating, low, intermediate, and high paclitaxel dose densities (25 microg, 50 microg, and 150 microg per stent) were investigated in porcine right coronary arteries (RCAs). Coronary and myocardial tissue concentration measurements and determination of on-stent paclitaxel and plasma concentrations were performed at 2, 8, 24, and 72 hours.
For all stents, uptake was similar at all time intervals (paclitaxel RCA concentration range, 1,610-33,300 ng). Low- and intermediate-dose stents showed similar RCA concentrations, but those for high-dose stents were three times greater. Residual on-stent paclitaxel concentration was not time-dependent, at 33.3% on low-, 30.6% on intermediate-, and 17.4% on high-dose stents. Paclitaxel was measurable in only the plasma immediately after stent placement, with a linear dose relationship and a timely regression: measurements in high-dose stents were 0.0454-0.656 ng/mL at 1 minute and 0.0329-0.0879 ng/mL at 5 minutes. Untreated control samples of the left coronary artery showed a linear dose-dependent concentration (12.6 ng/g, 21.2 ng/g, and 85.2 ng/g).
Overall coronary paclitaxel uptake is fairly independent from the baseline overall dose density and, hence, depends on immediate binding mechanisms of the arterial wall. This is supported by the fact that, regardless of the applied dose density, the kinetics of paclitaxel uptake did not follow an exposure time pattern.
Journal of vascular and interventional radiology: JVIR 08/2010; 21(8):1262-70. · 1.81 Impact Factor
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ABSTRACT: In part 1 of the present study, the authors demonstrated that coronary paclitaxel uptake from drug eluting stents (DESs) was not dependent on exposure time and dose. In this second part, the effect of the different paclitaxel dose densities on long-term biologic behavior was evaluated.
In 40 minipigs, (with 4- and 12-week follow-up), identical stents with the same three paclitaxel dose densities as in part 1 were implanted in the right coronary artery. Minipigs implanted with Polyzene-F nanocoated stents served as the control group. Quantitative angiography measuring average luminal diameter (from three in-stent reference points), minimal luminal diameter (from the point of maximum in-stent stenosis), average late loss, maximum late loss, and binary stenosis rate was performed, as was microscopy to determine neointimal thickening, injury score, and inflammation.
All three DESs were associated with a high average late loss, binary stenosis rate, and neointimal thickening, without significant differences. Drug-free stents had significantly less late in-stent stenosis: there was an average late loss of 0.3 mm +/- 0.3 in drug-free stents versus 0.8 mm +/- 0.2 in intermediate-dose stents and 1.5 mm +/- 0.6 in high-dose stents (P = .04). DES-associated inflammation was high in all DESs and six times higher as in the drug-free stents (Kornowski scores of 0.2 +/- 0.1 in drug-free stents, 1.3 +/- 0.9 in low-dose stents, 1.7 +/- 0.8 in intermediate-dose stents, and 1.3 +/- 1.0 in high-dose stents; P = .04). It worsened with time in all DESs, as did late in-stent stenosis.
The extensive and long-term retention of paclitaxel even in a low-dose formulation, at least according to the present labeling of DESs, might be associated with negative long-term results with regard to inflammation and late in-stent stenosis.
Journal of vascular and interventional radiology: JVIR 12/2009; 20(12):1608-16. · 1.81 Impact Factor
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ABSTRACT: To determine the arterial distribution pattern of the embolic agent Embozene within the porcine kidney and compare it with those of other spherical embolic agents.
Embozene, Embosphere, Bead Block, and Contour SE in size classes of 100-300 microm, 500-700 microm, and 700-900 microm and Embozene and Embosphere in the size class of 40-120 microm were used for total arterial occlusion in minipig kidneys. Organs were evaluated microscopically regarding vascular distribution of the different embolic agents and particle sizes.
The following variations of arterial distribution were identified. In the 40-120-microm size class, Embosphere particles penetrated significantly deeper compared with Embozene (P = .04). In the 100-300-microm size class, Bead Block showed a significantly deeper distribution as microscopy identified particles in arteries much smaller than their nominal size. In the 500-700-microm size class, Embosphere and Contour SE showed a deeper distribution. The most uniform arterial distribution was observed in the 700-900 microm size class,. However, few Embosphere and Contour SE particles were found in arcuate arteries, also indicating a distal distribution.
Throughout the four most-used size classes, from very small (40-120 microm) to large (700-900 microm), the distribution characteristics of the four tested materials vary substantially. Particularly, small Embosphere particles and small Bead Block particles showed a more distal distribution, as did medium-sized Embosphere and Contour SE particles. In the largest investigated size class, the distribution was more uniform. In general, the Embozene particles are very uniform in size, and they seem to reach vessels closely corresponding to their nominal size.
Journal of vascular and interventional radiology: JVIR 12/2009; 20(12):1597-607. · 1.81 Impact Factor
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ABSTRACT: Purpose of this study was to evaluate the frequency, probability, and factors associated with expulsion of submucosal fibroids after uterine artery embolization (UAE) in addition to the technical and clinical results at 1-year follow-up.
We determined the preinterventional volume of each dominant submucosal fibroid using the commonly used ellipsoid formula and a 3D volumetry in the MRI to define a threshold value in milliliters that indicates the probability for a fibroid expulsion. Assessment of fibroid expulsion was done by MRI at 3-month intervals for a year. Assessment of clinical mid term success was achieved by applying questionnaires at 1-year follow-up.
Technical success was observed in all 20 patients (mean age of 41.4+/-5.6 years; range: 29.2-51.1 years). Two (10%) minor and one (5%) major complications occurred. 10/20 dominant submucosal fibroids were completely expelled during the follow-up. Using 3D MRI volumetry the preinterventional mean volume of the later expelled fibroids was 56.8+/-57.0 ml (range 2.3-198.0 ml) and the mean volume of non-expelled fibroids was 123.8+/-147.3 ml (range 24.0-531.8 ml). This difference was statistically significant, but weak (p=0.0494). Fibroids with a volume equal or less than the threshold value (66.0 ml) were 73% likely to be expelled and fibroids larger than 66.0 ml were 78% likely not to be expelled. All 20 patients demonstrated a significant reduction in the fibroid related symptoms.
In our study the complication rate was low despite increased rates of fibroid expulsion (50%); simultaneously the rate of treatment satisfaction was very high. Patients with a dominant submucosal fibroid under 66.0 ml should be informed about the probability of fibroid expulsion and the accompanying symptoms.
European journal of radiology 09/2009; 75(1):e57-63. · 2.65 Impact Factor
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Boris Radeleff,
Lars Grenacher,
Patricia Christoph,
Christof M Sommer,
Ulrike Stampfl,
Stefanie Ramsauer,
Tina Henn,
Patrick Kurz,
Ruben Lopez-Benitez,
Irina Berger, Goetz M Richter
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ABSTRACT: To compare outcomes with a thermoplastic polyurethane (TPU)-covered self-expanding nitinol stent-graft (TPU graft) with those of a bare self-expanding nitinol stent in a porcine model.
Fourteen TPU grafts and 14 commercially available bare nitinol stents were implanted, one each, in the iliac arteries of 14 minipigs. Follow-up was performed at 1 week (six animals), 4 weeks (four animals), and 12 weeks (four animals). The primary study endpoint was in-stent stenosis assessed with quantitative angiography and microscopy. Secondary endpoints were injury, inflammation, and endothelialization.
After 1 week, the maximum percentage luminal loss was significantly greater in TPU grafts (average, 16.2%; range, 0.0%-35.8%) than in bare nitinol stents (8.2%; 0.0%-17.3%) (P = .04). Three of the four TPU grafts were occluded after 4 weeks, and all four TPU grafts were occluded after 12 weeks. Binary stenosis was seen in three of four bare nitinol stents after both 4 and 12 weeks. At 4-week follow-up, the average percentage luminal loss was significantly greater in TPU grafts (85.2%; 40.8%-100%) than in bare nitinol stents (49.5%; 37.9%-62.4%) (P = .003). The difference in neointimal height and percentage average stenosis between TPU grafts (1,028.7 microm and 68.4%) and bare nitinol stents (1,033.6 microm [918.0-1,118.40 microm] and 68.1% [60.44%-71.99%]) was not statistically significant. After 12 weeks, the average percentage luminal loss was 100% in TPU grafts due to occlusion of all stent-grafts and 24.9% (8.0%-63.9%) in bare nitinol stents (P = .011).
TPU grafts failed to provide improved patency compared with the bare nitinol stents because of excessive neointimal growth and subsequent occlusion. In addition, the bare nitinol stents showed considerable in-stent stenosis at angiography and microscopy.
Journal of vascular and interventional radiology: JVIR 08/2009; 20(7):927-35. · 1.81 Impact Factor
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ABSTRACT: To evaluate the immunohistochemical inflammatory reaction after porcine renal embolization with the new spherical embolic agent Embozene and to compare it with other spherical embolic agents.
After superselective porcine renal embolization (40 pigs) with different sizes of embolic agents (Embozene, Embosphere, Bead Block, Contour SE), tissue arrays were obtained (size ranges, 40-120 microm, 100-300 microm, 500-700 microm, 700-900 microm). After immunostaining for CD subtyping (CD45 and CD68) and cytokines (C-reactive protein [CRP] and interleukin-1 beta), a semiquantitative immunoreactivity score was calculated for each marker: intensity of staining was scored between 0 (negative) and 3 (intensive) and extent of staining between 0 and 4 (>80%), indicating the percentage of positive staining. The intensity score (0-3) was multiplied by the extent of staining score (0-4), resulting in a semiquantitative immunoreactivity score (0-12).
Analysis of cellular expression profiles (ie, CD45, CD68) revealed a significantly higher inflammatory score 4 weeks after embolization with Embosphere 100-300 microm particles than after embolization with Embozene, Bead Block, and Contour SE. After 12 weeks, the Embosphere 100-300 microm score decreased. Analysis of CRP expression showed similar results, with a significantly higher score 4 weeks after embolization with Embosphere 100-300 microm. In the size class used most frequently for uterine artery emboliation (500-700 microm), all scores were low (<2.5) and there was no significant difference among particle types.
Pronounced immunomarker expression was seen 4 weeks after embolization with small Embosphere particles. However, in general, modern spherical embolic agents cause a fairly low level of inflammatory reaction. In the present experimental setting, which is highly sensitive for specific tissue-to-agent reactivity, Embozene presented with low inflammatory results.
Journal of vascular and interventional radiology: JVIR 07/2009; 20(7):936-45. · 1.81 Impact Factor
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International Journal of Colorectal Disease 08/2008; 23(7):733-4. · 2.38 Impact Factor
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ABSTRACT: To evaluate the pattern of recanalization and specific inflammatory reaction after superselective embolization with four commercially available spherical embolic agents of different sizes in the mini pig kidney model.
In 40 mini pigs, the lower poles of both kidneys were superselectively embolized with Embozene, Embosphere, Bead Block, and Contour SE particles in sizes of 40-120 mircom (Embozene, Embosphere) and 100-300 microm, 500-700 microm, and 700-900 microm (Embozene, Embosphere, Bead Block, Contour SE). After a follow-up time of 4 or 12 weeks, recanalization was determined with angiography. Pathologic and histologic evaluation of the kidneys was performed, and the Banff 97 classification was used to evaluate the extent of vessel wall inflammation. Macroscopically visible ischemic changes were evaluated by using a specific ischemia score.
After embolization with Embozene microspheres, larger Embosphere particles, and Bead Block and Contour SE particles, the absence of inflammation or a low inflammation score was observed. Significantly elevated inflammation scores were evident with small Embosphere particles after 4 weeks (mean score, 1.21 +/- 1.0). Distinct recanalization occurred with Contour SE particles (100% recanalization with 100-300-microm particles at 12 weeks, 500-700-microm particles at 4 and 12 weeks, and 700-900-microm particles at 4 weeks). Ischemia scores were highest in the target area in all specimens. Mildly elevated ischemia scores in nontarget tissue areas were indicative of minor nontarget embolization.
Except for small Embosphere particles at 4 weeks, the absence of inflammatory reaction to the embolization procedure or only low inflammatory changes were observed with all embolic agents, particle sizes, and follow-up intervals. Recanalization was evident with all embolic agents; however, it was pronounced with Contour SE particles.
Journal of Vascular and Interventional Radiology 05/2008; 19(4):577-86. · 2.08 Impact Factor
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Michael Bernhard,
Torben K Becker,
Tim Nowe,
Marko Mohorovicic,
Marcus Sikinger,
Thorsten Brenner, Goetz M Richter,
Boris Radeleff,
Peter-Jürgen Meeder,
Markus W Büchler,
Bernd W Böttiger,
Eike Martin,
André Gries
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ABSTRACT: Successful management of emergency patients with multiple trauma in the hospital resuscitation room depends on the immediate diagnosis and rapid treatment of the most life-threatening injuries. In order to reduce the time spent in the resuscitation room, an in-hospital algorithm was developed in an interdisciplinary team approach with respect to local structures. The aim of the study was to analyse whether this algorithm affects the interval between hospital admission and the completion of diagnostic procedures and the start of life-saving interventions. Moreover, in-hospital mortality was investigated before and after the algorithm was introduced.
In this prospective study, all consecutive trauma patients in the resuscitation room were investigated before (group I, 01/04-10/04) and after (group II, 01/05-11/05) introduction of the algorithm. The times between hospital admission and the end of the diagnostic procedures (ultrasound [sono], chest X-ray [CF], and cranial computed tomography [CCT]), and between hospital admission and the start of life-saving interventions were registered and in-hospital mortality analysed.
In the study period, 170 patients in group I and 199 patients in group II were investigated. Injury severity score (ISS) were comparable between the two groups. The intervals between admission and completion of diagnostic procedures were significantly lower after the algorithm was introduced (mean+/-S.D.): sono (11 +/- 10 min versus 7 +/- 6 min, p < 0.05), CF (21 +/- 12 min versus 12 +/- 9 min, p < 0.01), and CCT (55 +/- 27 min versus 32 +/- 14 min, p < 0.01). Moreover, the interval to the start of life-saving interventions was significantly shorter (126 +/- 90 min versus 51 +/- 20 min, p < 0.01). After introducing the algorithm, in-hospital mortality was reduced significantly from 33.3% to 16.7% (p < 0.05) in the most severely injured patients (ISS>or=25).
The introduction of an algorithm for early management of emergency patients significantly reduced the time spent in the resuscitation room. The periods to completion of sono, CF, and CCT, respectively, and the start of life-saving interventions were significantly shorter after introduction of the algorithm. Moreover, introduction of the algorithm reduced mortality in the most severely injured patients. Although further investigations are needed to evaluate the effects of the Heidelberg treatment algorithm in terms of outcome and mortality, the time reduction in the resuscitation room seems to be beneficial.
Resuscitation 07/2007; 73(3):362-73. · 3.60 Impact Factor
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Stefanie Satzl,
Christina Henn,
Patricia Christoph,
Patrick Kurz,
Ulrike Stampfl,
Sibylle Stampfl,
Florian Thomas,
Boris Radeleff,
Irina Berger,
Michael Grunze, Goetz M Richter
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ABSTRACT: Previous experimental studies have demonstrated that poly[bis(trifluoroethoxy)phosphazene] (PTFEP) nanocoated stents have antithrombotic characteristics, reduce in-stent stenosis, prevent wall inflammation, and do not hamper endothelialization. This study was designed to validate these findings in a porcine coronary artery model.
PTFEP-coated (n = 15) and bare stents (n= 13) were implanted in coronary arteries of 18 mini-pigs (4- and 12-week follow-up). Primary study endpoints were thrombogenicity and in-stent stenosis, secondary study endpoints were inflammatory response and re-endothelialization evaluated by quantitative angiography and light microscopy.
No thrombus deposition occurred on any stent. At 4 weeks follow-up, the bare stents (n = 4) had a significantly smaller neointimal area (1.93 vs. 3.20 mm(2), P = 0.009). At 12 weeks, PTFEP-coated stents (n = 11) had significantly superior results in almost all parameters: neointimal area (2.25 vs. 2.65 mm(2), P = 0.034), neointimal height (204.46 vs. 299.41 microm, P = 0.048), percentage stenosis (38.25 vs. 50.42%, P = 0.019), and inflammation score (0.12 vs. 0.30, P = 0.029). Complete re-endothelialization was seen in both stent types at both intervals.
At long-term follow-up, the superior results of PTFEP-coated stents were characterized by a noteworthy reduction of neointimal growth and inflammatory response.
Investigative Radiology 06/2007; 42(5):303-11. · 4.59 Impact Factor
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ABSTRACT: We sought to evaluate the new polymer PTFEP (poly(bis(trifluoroethoxy)phosphazene) for (1) its ability to reduce thrombogenicity and late in-stent stenosis and (2) its effect on endothelialization in a rabbit iliac artery model.
Nanocoated ( approximately 50 nm) and bare stainless-steel stents were implanted bilaterally in the iliac arteries of 30 New Zealand White rabbits (1, 4, 8, 12, and 16 weeks follow-up) and evaluated by angiography, light, and scanning electron microscopy.
Bilateral stent placement was successful in 27 of 30 rabbits. Thrombus depositions occurred in none of the 27 coated but in 4 of the 27 bare stents (P=0.037). A normal angiogram was obtained in 18 of 22 coated stents at risk for restenosis (follow-up >or=4 weeks) but only in 13 of 22 bare stents (P=0.023). Marked restenosis (luminal loss >30%) was found in 6 bare stents (P=0.011) but not in any coated stents. The neointima was 47.7-73.9 mum on coated and 66.9-115.2 mum on bare stents (statistically significant at 4, 8, and 16 weeks). Scanning electron microscopy detected full endothelialization in all stents from 4 weeks on (22 stents in both groups).
PTFEP nanocoating successfully showed thromboresistance and reduced late in-stent stenosis. Endothelialization was equal in both stent types. Studies in more human-like models and human feasibility studies in human arteries are encouraged.
Investigative Radiology 05/2005; 40(4):210-8. · 4.59 Impact Factor
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ABSTRACT: We report a rare case of late transjugular intrahepatic portosystemic stent shunt (TIPSS) occlusion due to progressive stent protrusion into the periportal liver parenchyma, which was a result of delayed liver shrinkage 2 years after TIPSS. The initial TIPSS procedure had been carried out in a 52-year-old man as a bridge for liver transplantation because of post-alcoholic liver cirrhosis. We describe the applied TIPSS recanalization and revision technique. Immediately after TIPSS revision acute liver failure developed, which required emergency liver transplantation.
CardioVascular and Interventional Radiology 31(1):209-14. · 2.09 Impact Factor
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ABSTRACT: We report a rare case of two communicating pseudoaneurysms of the common hepatic artery 1 month postoperatively following pylorus-preserving pancreaticoduodenectomy due an abscess formation. We describe the superselective transcatheteral embolization technique with deployment of interlocking detachable coils and Histoacryl-Lipiodol in this case and discuss the recent literature. Despite the technical success by achieving hemodynamic stability with initial preservation of liver function, the patient died 23 days postembolization due to multiorgan failure.
CardioVascular and Interventional Radiology 30(1):129-32. · 2.09 Impact Factor
