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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Besjakov, Jack, et al.
(author)
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Effect on cardiac contractile force from addition of cations and oxygen to iohexol. Comparison with other low-osmotic contrast media in the isolated rabbit heart during normal and reduced perfusion pressure
- 1993
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In: Acta Radiologica. - 1600-0455. ; 34:4, s. 381-387
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Journal article (peer-reviewed)abstract
- The coronary arteries of the isolated rabbit heart were perfused with different contrast media (CM). The effects on cardiac contractile force (CF) from enriching iohexol solutions with sodium, calcium, potassium, magnesium and oxygen were investigated. The effects were studied during normal and reduced perfusion pressure; the latter was intended to simulate flow conditions distal to proximal stenotic processes of the coronary arteries. By adding the above mentioned cations to iohexol (175 mg I/ml) the smallest influence on CF was found when the CM contained 30 mM NaCl, 0.3 mM CaCl2, 0.9 mM KCl and 0.3 mM MgCl2 and this influence on CF was significantly less than caused by iohexol with 30 mM NaCl (p < or = 0.01). The influence on CF was further reduced when this iohexol solution was oxygenated with 100% oxygen (p < or = 0.001). This modified iohexol solution caused a significantly smaller influence on CF than the low-osmotic media iohexol, iopamiro, ioversol and ioxaglate (p < or = 0.001). Ioxaglate caused the greatest decrease in CF of all the CM (p < or = 0.001) and to a greater extent during reduced flow than during normal flow (p < or = 0.01). In conclusion, iohexol enriched with a balanced electrolyte solution and saturated with oxygen had a smaller adverse effect on contractility than iohexol, iopamidol, ioversol and ioxaglate.
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| 6. |
- Besjakov, Jack, et al.
(author)
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Reduced risk of ventricular fibrillation by balancing sodium, calcium, potassium and magnesium added to nonionic contrast media. An investigation in the isolated rabbit heart
- 1993
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In: Acta Radiologica. - 1600-0455. ; 34:3, s. 246-251
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Journal article (peer-reviewed)abstract
- The effect of addition of calcium, potassium and magnesium to iohexol (350 mg I/ml) enriched with 30 mM sodium was investigated with regard to ventricular fibrillation (VF) in isolated rabbit hearts. Enriching iohexol containing 30 mM sodium with increasing amounts of calcium (0-1.2 mM) caused an increase in the frequency of VF. Increasing amounts of potassium (0-3.8 mM) to iohexol with 30 mM Na + 0.15 mM Ca + 0.1 mM Mg reduced the risk of VF. However, this protective effect of potassium on VF was reduced if magnesium was removed from the test solution. Furthermore, increasing amounts of magnesium (0-1.2 mM) to iohexol with 30 mM Na + 0.15 mM Ca + 0.4 mM K led to an increased frequency of VF. Iohexol with 30 mM Na + 0.3 mM Ca + 0.9 mM K + 0.3 mM Mg caused no VF. It is of interest to add multiple cations to sodium-containing nonionic media to improve cardiac contractility following coronary perfusion. The present study indicates that it is possible to enrich iohexol 350 mg I/ml + 30 mM Na with calcium, potassium and magnesium in small amounts, and balanced with respect to each ion, without changing the risk of VF.
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| 7. |
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| 8. |
- Chai, Chun-Ming, et al.
(author)
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Incidence of Ventricular Fibrillation during Left Coronary Arteriography in Pigs: Comparison of a Solution of the Nonionic Dimer Iodixanol with Solutions of Five Different Nonionic Monomers
- 2008
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In: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 49:2, s. 150-156
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Journal article (peer-reviewed)abstract
- Background: Solutions of iodine contrast media (CM) used for selective coronary arteriography (CA) should have minimal propensity to cause ventricular fibrillation (VF). Commonly used CM for CA are nonionic monomers or dimers. Purpose: To compare VF propensity of ready-to-use solutions of one nonionic dimer, iodixanol, and five nonionic monomers, iobitridol, iopamidol, iomeprol, iopromide, and ioversol. Material and Methods: Twenty milliliters of each CM was injected into the left coronary artery (LCA) through an inflated balloon catheter (0.5 ml/s) in 14 pigs; the longest period of injection was 40 s. If VF occurred before 40 s, the injection was stopped and the heart was defibrillated. After VF, there was a delay of 40 min before the next injection. Hemodynamic parameters and vector electrocardiography (VECG) were monitored. A CM with a lower frequency of VF and a longer period between start of injection and start of VF was considered to have a lower VF propensity. Results: Following 14 injections, each of the five nonionic monomers caused 14 VF, whereas iodixanol caused three VF (P<0.01). When VF occurred after iodixanol, it occurred later than after the other CM (P<0.001). Iodixanol caused less prolongation in QRS time (P<0.01) and QTc time (P<0.05) than the other CM. Prolongations in QRS and QTc times caused by CM parallel the VF propensities of the CM. Conclusion: Ready-to-use solutions of the dimer iodixanol have lower VF propensity than solutions of the five monomeric CM. This is related to the fact that the solutions of the dimer iodixanol have lower osmolality, higher viscosity, and higher concentrations of NaCl and CaCl2 than solutions of the five monomers.
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| 9. |
- Chai, Chun-Ming, et al.
(author)
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Signs in Vector-Electrocardiography (VECG) Predicting the Fibrillatory Propensity of Iodixanol and Mannitol Solutions After Injection Into the Left Coronary Artery of Pigs.
- 2007
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In: Academic Radiology. - : Elsevier BV. - 1878-4046 .- 1076-6332. ; 14:2, s. 162-177
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Journal article (peer-reviewed)abstract
- Rationale and Objectives. To find signs in vector-electrocardiography (VECG) predicting the ventricular fibrillatory propensity (VF-PROP) of iodixanol and mannitol solutions after injection into the left coronary artery (LCA) of pigs. Materials and Methods. Five plasma-isotonic solutions perfused LCA: lod 320 + Na/Ca (iodixanol 320 mg I/mL, 19 mM NaCl, 0.3 mM CaCl2), lod 320 + Mann (iodixanol 320 mg I/mL, 50 mM mannitol), Mann + Na/Ca (240 mM mannitol, 19 mM NaCl, 0.3 mM CaCl2) Mann (275 mM mannitol), and Ringer (representing "physiologic electrolytes"). The first two solutions have at 37 degrees C viscosity 13 mPas and the others <1 mPas. In eight pigs, 20 mL of each solution was injected twice for 10 seconds, and in 15 pigs, each solution was injected for 11-40 seconds (0.5 mL/second) through a wedged catheter in the LCA. If ventricular fibrillation (VF) occurred, injection was stopped and heart was defibrillated. If VF did not occur, perfusion period was 40 seconds. A higher frequency of VF and a shorter period from start of injection until start of VF gave a solution a higher ranking of VF-PROP. Results. The 10-second injections caused no VF. Ringer and lod 320 + Na/Ca caused no VF after 40-second injections, whereas the other solutions caused VF. Ranking the solutions from lowest to highest VF-PROP gave: Ringer = lod 320 + Na/Ca < lod 320 + Mann < Mann + Na/Ca < Mann. Prolongation of QRS time and QTc time were the only VECG signs that showed significant differences (P <.05) between all solutions and correctly ranked the VF-PROP of all solutions in both animal groups. Conclusion. The results fit with the concept that a more physiologic electrolyte composition and a higher viscosity of a test solution will, after start of injection of that solution into LCA, delay changes in the electrolyte composition in myocardial interstitial fluid and also delay start of VF. If a plasma isotonic contrast medium (CM) with lower viscosity than that of iodixanol at 320 mgI/mL were created, we conclude that such a CM should have electrolyte composition closer to that of Ringer than present composition (19 mM NaCl and 0.3 mM CaCl2) to counteract the effects of faster diffusion of nonphysiologic electrolyte composition from the low-viscosity CM to myocardial interstitial fluid.
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| 10. |
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| 11. |
- Elmståhl, Barbara, et al.
(author)
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Gadolinium contrast media are more nephrotoxic than iodine media. The importance of osmolality in direct renal artery injections
- 2006
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In: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 16:12, s. 2712-2720
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Journal article (peer-reviewed)abstract
- A study was undertaken of the role of osmotoxicity in gadolinium (Gd) and iodine contrast media (CM) nephrotoxicity in ischemic porcine kidneys. Test solutions: mannitol iso-osmotic to 0.5 M: gadopentetate (1.96 Osm/kg H2O), 0.5 M: gadodiamide (0.78 Osm/kg H2O) and 0.5 M: iohexol (190 mg I/ml, 0.42 Osm/kg H2O). Each solution was injected [3 ml/kg body weight (BW)] into the balloon-occluded (10 min) renal artery of eight left-sided nephrectomized pigs. The plasma half-life of a glomerular filtration rate (GFR) marker was used to compare their effects on GFR 1-3 h post-injection. The median half-lives of the GFR marker after injection of gadopentetate (1,730 min) and mannitol 1.96 Osm/kg H2O (2,782 min) did not differ statistically (P = 0.28), but were significantly longer than after all other solutions (P < 0.001). There was no significant difference (P = 0.06) between gadodiamide (218 min) and mannitol 0.82 Osm/kg H2O (169 min), while there was (P = 0.03) between iohexol (181 min) and mannitol 0.43 Osm/kg H2O (148 min). The difference between gadodiamide and iohexol was significant (P = 0.01). Reduction in GFR, as a marker of nephrotoxicity, induced by gadopentetate correlated with its high osmolality, while the effect of gadodiamide and iohexol may include chemotoxicity. Iohexol molecules were less nephrotoxic than the Gd-CM molecules and contain three-times the number of attenuating atoms per molecule.
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| 12. |
- Elmståhl, Barbara, et al.
(author)
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Histomorphological Changes after Renal X-Ray Arteriography Using Iodine and Gadolinium Contrast Media in an Ischemic Porcine Model.
- 2007
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In: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 48:10, s. 1109-1119
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Journal article (peer-reviewed)abstract
- Background: Gadolinium contrast media (Gd-CM) are regarded as non-nephrotoxic or considerably less nephrotoxic than iodine contrast media (I-CM), and have therefore come to be used as a substitute for I-CM in patients with renal insufficiency in a variety of radiographic examinations. Purpose: To investigate renal histomorphological changes caused by Gd-CM in comparison with I-CM after renal X-ray arteriography in an ischemic porcine model, and to evaluate these changes in relation to the nephrotoxicity of the CM used. Material and Methods: Test solutions: gadopentetate, gadodiamide, iohexol, gadobutrol, iopromide, iodixanol, mannitol, and saline. The experiments were performed on 152 animals. Each pig was randomized to receive one test solution injected into the balloon-occluded (10 min) right renal artery. The kidneys were evaluated histomorphologically. The severity of histomorphological changes was graded subjectively: 1 = minimal, 2 = mild, 3 = moderate, and 4 = marked. Results: The main histological changes were 1) proximal tubular and glomerular necrosis, 2) hemorrhage/congestion of the cortex, medulla, and glomeruli, 3) proximal tubular vacuolation, and 4) protein-filled tubules in the cortex and medulla. Necrosis and hemorrhage/congestion were more frequent after injections with gadopentetate, mannitol solution iso-osmotic to gadopentetate, and gadobutrol compared to all other groups (P<0.001). The degree of necrosis and hemorrhage/congestion was related to the degree of impairment of renal function, but inversely related to vacuolation and tubular protein filling. Conclusion: In ischemic porcine kidneys, the histomorphological changes caused by Gd-CM are similar to those caused by I-CM. Vacuolation appears to be independent of the osmolality and viscosity of the CM, and does not seem to be an indicator of renal impairment. “High-osmolal” Gd-CM are more nephrotoxic than “low- and iso-osmolal” I-CM when compared in equal volumes of concentrations, resulting in equal X-ray attenuation.
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| 13. |
- Elmståhl, Barbara, et al.
(author)
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Iodixanol 320 results in better renal tolerance and radiodensity than do gadolinium-based contrast media: Arteriography in ischemic porcine kidneys
- 2008
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In: Radiology. - : Radiological Society of North America (RSNA). - 1527-1315 .- 0033-8419. ; 247:1, s. 88-97
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Journal article (peer-reviewed)abstract
- Purpose: To prospectively compare nephrotoxicity and radiodensity of plasma hyperosmotic gadolinium chelates (attenuation-osmotic ratio of 1: 1) with those of plasma iso-osmotic iodine-based contrast media (attenuation-osmotic ratio of 3: 1 or 6: 1) after renal arteriography in ischemic porcine kidneys. Materials and Methods: The local animal care committee approved this study. The following contrast media were used: (a) iodixanol (150 mg of iodine per milliliter and 320 mg I/mL, 0.29 osm/kg H2O), (b) iopromide (150 mg I/mL, 0.34 osm/kg), (c) 0.5 mol/L gadodiamide (0.78 osm/kg), and (d) 1.0 mol/L gadobutrol (1.6 osm/kg). After left-sided nephrectomy, contrast media (3 mL per kilogram of body weight) were injected (20 mL/min) in a noncrossover design into the right renal artery of pigs during a 10-minute ischemic period. There were eight pigs in each group and one group for each contrast medium. We compared histomorphology, radiographic contrast medium excretion, subjective radiodensity of nephrograms (70 kVp) at the end of injection, and contrast medium plasma half-life elimination times 1-3 hours after injection. Longer elimination times resulted in lower glomerular filtration rates. Results: Gadobutrol caused extensive tubular necrosis and moderate glomerular necrosis; gadodiamide and iopromide, minimal to mild tubular necrosis; and iodixanol, no necrosis. Gadobutrol was the only contrast medium to show no sign of excretion, and its plasma half-life elimination time (median, 1103 minutes; P = .001) was significantly longer than that of other contrast agents. Gadodiamide had a significantly longer plasma half-life elimination time (median, 209 minutes; P = .01) than did iodine-based contrast media (median, 136-142 minutes). The 320 mg I/mL dose of iodixanol had the highest radiodensity, whereas gadodiamide had the lowest radiodensity. The radiodensity of the 320 mg I/mL dose of iodixanol was greater than that of the 150 mg I/mL dose of iodixanol, which was equal to the radiodensities of the 150 mg I/mL dose of iopromide and 1.0 mol/L gadobutrol, which in turn were greater than that of 0.5 mol/L gadodiamide. Conclusion: Plasma iso-osmotic iodine-based contrast media used at commercially available concentrations have superior attenuation and nephrotoxic profiles compared with equal volumes of hyperosmotic nonionic 0.5-1.0 mol/L gadolinium-based contrast media when performing renal arteriographic procedures. (c) RSNA, 2008.
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| 14. |
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| 15. |
- Frennby, Bo, et al.
(author)
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Clearance of iohexol, 51Cr-EDTA and endogenous creatinine for determination of glomerular filtration rate in pigs with reduced renal function: a comparison between different clearance techniques
- 1997
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In: Scandinavian Journal of Clinical & Laboratory Investigation. - 1502-7686. ; 57:3, s. 241-252
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Journal article (peer-reviewed)abstract
- In order to simplify and/or improve determination of glomerular filtration rate (GFR) the clearances of iohexol, 51Cr-EDTA and endogenous creatinine were simultaneously determined with different techniques in 21 anesthetized landrace pigs. Their GFR had been reduced to about 1/3 or less of normal GFR. After an intravenous bolus of the GFR markers, their plasma concentration curves were followed for 6 hours with 16 plasma samples. A bladder catheter collected urine during six 60-min periods. The plasma clearance was calculated by dividing "dose of marker" with "area under the plasma concentration curve" (AUC) from the time of injection to infinity using a one- (Clprovisional) and a three-compartment (ClAUC-3comp) model. The renal clearance of iohexol and 51Cr-EDTA was calculated by dividing the amount of marker excreted in the urine in a period by AUC in the same period. The AUC was for iohexol and 51Cr-EDTA determined by integrating the total area in the period (Clren adv)-our reference method representing the "true" GFR and for creatinine determined by using the arithmetic mean of the plasma concentration of the marker at the start and at the end of the urine collection period (Clren simple). Renal clearance of creatinine was significantly lower than renal clearance of iohexol (p = 0.0019) and 51Cr-EDTA (p = 0.0001). There were no significant differences between the renal clearances (Clren adv) of iohexol and 51Cr-EDTA or between their plasma clearances (ClAUC-3comp). For iohexol the median overestimation of the "true" GFR with Clprovisional was higher when "early" plasma samples (30-120 min) were used (4.5 ml min-1 10 kg-1) than when late samples (180-360 min) were used (1.9 ml min-1 10 kg-1). Subtraction of the median extrarenal clearance (known from a study of nephrectomized pigs) from the plasma clearances (ClAUC-3comp) of iohexol and 51Cr-EDTA in pigs with reduced renal function decreased the median overestimation of the "true" GFR from 1.9 to 1.0 ml min-1 10 kg-1 with iohexol and from 1.7 to 0.9 ml min-1 10 kg-1 with 51Cr-EDTA. The plasma clearance technique may be improved in pigs with reduced GFR by (i) including a "late" plasma sample in three- and one-compartment models, which tends to increase the AUC; (ii) introducing a correction formula by normalizing the GFR values of the one-compartment model to those of the three-compartment model, thereby compensating for the rapid early changes in plasma concentration of marker after the bolus injection of the marker; or (iii) subtracting a median (or mean) extrarenal clearance of the marker in pigs from the plasma clearance [according to (i) or (ii)]. The plasma clearance one-compartment technique may be improved in pigs with various levels of GFR values by normalizing the plasma clearance values to the renal clearance values, thereby compensating for both the early changes in plasma concentration of marker and the extrarenal clearance of marker.
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| 16. |
- Frennby, Bo, et al.
(author)
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Clearance of iohexol, chromium-51-ethylenediaminetetraacetic acid, and creatinine for determining the glomerular filtration rate in pigs with normal renal function: comparison of different clearance techniques
- 1996
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In: Academic Radiology. - 1878-4046. ; 3:8, s. 651-659
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Journal article (peer-reviewed)abstract
- RATIONALE AND OBJECTIVES: We wanted to improve determination of the glomerular filtration rate (GFR) with plasma clearance techniques because the alternative-renal clearance techniques-may involve inaccurate urine sampling or risk of urinary tract infection when bladder catheterization becomes necessary. Therefore, we compared the renal and plasma clearances of iohexol and chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), as well as endogenous creatinine clearance, in 19 normal pigs using different techniques. METHODS: After an intravenous bolus injection of the GFR markers, 16 plasma samples were used to plot the marker concentrations versus time for 4.5 hr. Urine was collected during nine 30-min periods. Plasma clearance was calculated by dividing the dose of marker with the area under the plasma concentration curve (AUC) from the time of injection to infinity using one-compartment (ClAUC-slope) and three-compartment (ClAUC-3comp) models. The renal clearance was calculated by dividing the amount of marker excreted in the urine in a period with the AUC in the same period. This AUC was determined by integrating the total area in the period (Clren adv)--our reference method representing the "true" GFR--or by using the arithmetic mean of the plasma concentrations of the marker at the beginning and end of the urine collection period (Clren simple). Creatinine clearance was determined according to Clren simple. RESULTS: Renal clearances of iohexol and 51Cr-EDTA were significantly higher than creatinine clearance (P = .0002). There was no significant difference between the renal clearances of iohexol and 51Cr-EDTA or between their plasma clearances. The two mathematical methods of calculating the renal clearance of iohexol were highly correlated (rs = .99), as were the two methods of calculating its plasma clearance (rs = .95). Because of the extrarenal clearance of the markers, the plasma clearance methods for iohexol and 51Cr-EDTA always overestimated the true GFR. ClAUC-3comp was the method closest to the true GFR. For iohexol, the median overestimation of the GFR was higher with ClAUC-slope when early plasma samples (30-120 min) after injection of the marker were used (5.5 ml.min-1.10 kg-1) than when late samples (180-270 min) were used (4.0 ml.min-1.10 kg-1). After subtracting the median extrarenal clearances of iohexol and 51Cr-EDTA (previously determined in nephrectomized pigs) from their plasma clearances (ClAUC-3comp), the median overestimation of the true GFR was reduced from 2.0 to 1.1 ml.min-1.10 kg-1 with iohexol and from 2.1 to 1.3 ml.min-1.10 kg-1 with 51Cr-EDTA. CONCLUSION: GFR determination with plasma clearance techniques can be improved in three- and one-compartment models by taking late plasma samples and by subtracting the extrarenal plasma clearance of the species. One-compartment models can be improved by determining a correction formula in the species for the early parts of the decay curve of the plasma concentration of the marker
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| 17. |
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| 18. |
- Frennby, Bo, et al.
(author)
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Determination of the relative glomerular filtration rate of each kidney in man : Comparison between iohexol CT and 99mTc-DTPA scintigraphy
- 1995
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In: Acta Radiologica. - 0284-1851 .- 1600-0455. ; 36:4, s. 410-417
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Journal article (peer-reviewed)abstract
- Iohexol and 99mTc-DTPA were used in 43 patients to determine the relative glomerular filtration rate (GFR), i.e., the GFR of each kidney in percent of total GFR. The amount of any GFR marker accumulating in Bowman's space, tubuli and renal pelvis within a few minutes after i.v. injection, before any marker had left the kidney via the ureter, was defined as proportional to the GFR of that kidney. The renal accumulation of iohexol was determined by CT using 10 slices of 8-mm thickness 1 to 4 minutes after injection. The renal accumulation of 99mTc-DTPA was determined with a gamma camera within 2 minutes after injection. The correlation coefficient between the two methods was 0.98. Due to the higher radiation dose from CT than from 99mTc-DTPA injection, relative GFR determination with CT should be performed when there is also a diagnostic need to reveal morphology.
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| 19. |
- Frennby, Bo, et al.
(author)
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Extrarenal plasma clearance of iohexol, chromium-51-ethylenediaminetetraacetic acid, and inulin in anephric pigs
- 1996
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In: Academic Radiology. - 1878-4046. ; 3:2, s. 145-153
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Journal article (peer-reviewed)abstract
- RATIONALE AND OBJECTIVES: To improve the measurement of the glomerular filtration rate (GFR), we determined the extrarenal plasma clearance of the GFR markers iohexol, chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), and inulin using 11 anephric pigs. METHODS: After an intravenous (i.v.) bolus injection of the markers, the decay curves of their plasma concentrations were monitored for 29 hr by 16 plasma samples. The area under the curve (AUC; concentration of marker versus time) was calculated according to one- and three-compartment kinetics. The extrarenal clearance was calculated by dividing the dose of marker by the AUC. RESULTS: In the three-compartment model, the median of the extrarenal clearances of iohexol, 51Cr-EDTA, and inulin were 0.87 ml.min-1.10 kg-1 (range = 0.62-1.26 ml.min-1.10 kg-1), 0.79 ml.min-1.10 kg-1 (range = 0.61-1.04 ml.min-1.10 kg-1), and 0.83 ml.min-1.10 kg-1 (range = 0.65-1.17 ml.min-1.10 kg-1). The extrarenal clearance of 51Cr-EDTA was slightly lower than that of iohexol and inulin when measured with the three-compartment model (p = .015). There was no statistically significant difference between the two models of kinetics in calculating clearance of the same marker. CONCLUSION: Our results indicate that subtracting the median values of the extrarenal clearance of the markers from the total plasma clearance will provide GFR values closer to the "true" GFR. This technique might prove useful in GFR calculations in patients with a very low GFR (e.g., residual GFR in patients on dialysis)
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| 20. |
- Frennby, Bo, et al.
(author)
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The use of iohexol clearance to determine GFR in patients with severe chronic renal failure - a comparison between different clearance techniques
- 1995
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In: Clinical Nephrology. - 0301-0430. ; 43:1, s. 35-46
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Journal article (peer-reviewed)abstract
- The nonionic low-osmolar contrast medium iohexol was used as marker of glomerular filtration rate (GFR) in 53 patients with stable renal function (group I: n = 32, group II: n = 21). All the patients had clearance values < or = 30 ml.min-1.1.73 m-2 body surface; 40 patients < 20 ml.min-1.1.73 m-2 body surface. Simultaneous determinations of renal clearance and plasma clearance, both as slope clearance and single sample clearance, were performed after intravenous injection of 10 ml iohexol 300 mg iodine/ml. In groups I and II plasma was sampled early (around 3 hours) and late (up to 24 hours) after the injection. In group I urine was collected during four 40-minute periods and in group II during one 3-hour period and in group II the residual urine was estimated by ultrasound. Plasma and urine iodine concentrations were analyzed with X-ray fluorescence technique (Reanalyzer PRX90, Provalid AB, Sweden). In group II S-creatinine and tubular function test were followed to detect any signs of nephrotoxicity. In 6 anuric patients (group III) 10 ml iohexol 300 mg I/ml was injected to assess its extrarenal clearance. In groups I and II the slope clearance correlated excellently with the single sample clearance (r = 0.99) when a late plasma sample was used in both techniques. In group II, where residual urine was estimated by ultrasound, renal clearance correlated better with slope clearance than in group I (r = 0.94 vs r = 0.89). There were no signs of nephrotoxicity in the parameters noted. In group III, extrarenal plasma clearance of iohexol did not exceed 2 ml.min-1.1.73 m-2. CONCLUSION: GFR < 20 ml/min can accurately and safely be determined as renal clearance or plasma clearance of iohexol after an intravenous dose of 10 ml 300 mg I/ml. Plasma clearance techniques, which have the practical clinical advantage of no urine sampling, do at low GFR require a late plasma sample taken, for instance, 24 hours after injection of iohexol, irrespective of whether slope technique or single sample technique or one-compartment or poly-compartment models are used.
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| 21. |
- Karlsson, Jan Olof G, et al.
(author)
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Calmangafodipir [Ca4Mn(DPDP)5], mangafodipir (MnDPDP) and MnPLED with special reference to their SOD mimetic and therapeutic properties.
- 2015
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In: Drug Discovery Today. - : Elsevier BV. - 1878-5832 .- 1359-6446. ; 20:4, s. 411-421
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Research review (peer-reviewed)abstract
- Reactive oxygen species (ROS) and reactive nitrogen species (RNS) participate in pathological tissue damage. Mitochondrial manganese superoxide dismutase (MnSOD) normally keeps ROS and RNS in check. During development of mangafodipir (MnDPDP) as a magnetic resonance imaging (MRI) contrast agent, it was discovered that MnDPDP and its metabolite manganese pyridoxyl ethyldiamine (MnPLED) possessed SOD mimetic activity. MnDPDP has been tested as a chemotherapy adjunct in cancer patients and as an adjunct to percutaneous coronary intervention in patients with myocardial infarctions, with promising results. Whereas MRI contrast depends on release of Mn(2+), the SOD mimetic activity depends on Mn(2+) that remains bound to DPDP or PLED. Calmangafodipir [Ca4Mn(DPDP)5] is stabilized with respect to Mn(2+) and has superior therapeutic activity. Ca4Mn(DPDP)5 is presently being explored as a chemotherapy adjunct in a clinical multicenter Phase II study in patients with metastatic colorectal cancer.
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| 22. |
- Kjellson, Fred, et al.
(author)
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Bone cement X-ray contrast media: A clinically relevant method of measuring their efficacy.
- 2004
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In: Journal of Biomedical Materials Research. Part B - Applied Biomaterials. - : Wiley. - 1552-4981 .- 1552-4973. ; 70B:2, s. 354-361
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Journal article (peer-reviewed)abstract
- It is important to compare different contrast media used in bone cement according to their ability to attenuate X-rays and thereby produce image contrast between bone cement and its surroundings in clinical applications. The radiopacity of bone cement is often evaluated by making radiographs of cement in air at an X-ray tube voltage of 40 kV. We have developed a method for ranking contrast media in bone cement simulating the clinical situation, by (1) choosing the same X-ray tube voltage as used in clinical work, and (2) using a water phantom to imitate the effects of the patients' soft tissue on the X-ray photons. In clinical work it is desirable to have low radiation dose, but high image contrast. The voltage chosen is a compromise, because both dose and image contrast decrease with higher voltage. Three contrast media (ZrO2, BaSO4, and Iodixanol) have been compared for degree of "image contrast." Comparing 10 wt % contrast media samples at an X-ray tube voltage of 40 kV, ZrO2 produced higher image contrast than the other media. However, at 80 kV, using a water phantom, the results were reversed, ZrO2 produced lower image contrast than both BaSO4 and Iodixanol. We conclude that evaluations of contrast media should be made with voltages and phantoms imitating the clinical application. (C) 2004 Wiley Periodicals, Inc.
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| 23. |
- Kjellson, Fred, et al.
(author)
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Tensile properties of a bone cement containing non-ionic contrast media
- 2001
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In: Journal of Materials Science: Materials in Medicine. - 1573-4838. ; 12:10-12, s. 889-894
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Journal article (peer-reviewed)abstract
- The addition of contrast media such as BaSO4 or ZrO2 to bone cement has adverse effects in joint replacements, including third body wear and particle-induced bone resorption. Ground PMMA containing particles of the non-ionic water-soluble iodine-based X-ray contrast media, iohexol (IHX) and iodixanol (IDX), has, in bone tissue culture, shown less bone resorption than commercial cements. These water-soluble non-ceramic contrast media may change the mechanical properties of acrylic bone cement. The static mechanical properties of bone cement containing either IHX or IDX have been investigated. There was no significant difference in ultimate stress between Palacos R (with 15.0 wt % of ZrO2) and plain cement with 8.0 wt % of IHX or IDX with mass median diameter (MMD) of 15.0 or 16.0 microm, while strain to failure was higher for the latter (p < 0.02). The larger particles (15.0 or 16.0 microm) gave significantly higher (p < 0.001) ultimate tensile strengths and strains to failure than smaller sizes (2.4 or 3.6 microm). Decreasing the amount of IHX from 10.0 wt % to 6.0 wt % gave a higher ultimate tensile strength (p < 0.001) and strain to failure (p < 0.02). Scanning electron microscopy (SEM) showed the smaller contrast media particles attached to the surface of the polymer beads, which may prevent areas of the acrylate bead surface from participating in the polymerization. In conclusion, the mechanical properties of bone cement were influenced by the size and amount of contrast medium particles. By choosing the appropriate amount and size of particles of water-soluble non-ionic contrast media the mechanical properties of the new radio-opaque bone cement can be optimized, thus reaching and surpassing given regulatory standards.
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| 24. |
- Le Duc, Diana, et al.
(author)
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Kiwi genome provides insights into evolution of a nocturnal lifestyle
- 2015
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In: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 16
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Journal article (peer-reviewed)abstract
- Background: Kiwi, comprising five species from the genus Apteryx, are endangered, ground-dwelling bird species endemic to New Zealand. They are the smallest and only nocturnal representatives of the ratites. The timing of kiwi adaptation to a nocturnal niche and the genomic innovations, which shaped sensory systems and morphology to allow this adaptation, are not yet fully understood. Results: We sequenced and assembled the brown kiwi genome to 150-fold coverage and annotated the genome using kiwi transcript data and non-redundant protein information from multiple bird species. We identified evolutionary sequence changes that underlie adaptation to nocturnality and estimated the onset time of these adaptations. Several opsin genes involved in color vision are inactivated in the kiwi. We date this inactivation to the Oligocene epoch, likely after the arrival of the ancestor of modern kiwi in New Zealand. Genome comparisons between kiwi and representatives of ratites, Galloanserae, and Neoaves, including nocturnal and song birds, show diversification of kiwi's odorant receptors repertoire, which may reflect an increased reliance on olfaction rather than sight during foraging. Further, there is an enrichment of genes influencing mitochondrial function and energy expenditure among genes that are rapidly evolving specifically on the kiwi branch, which may also be linked to its nocturnal lifestyle. Conclusions: The genomic changes in kiwi vision and olfaction are consistent with changes that are hypothesized to occur during adaptation to nocturnal lifestyle in mammals. The kiwi genome provides a valuable genomic resource for future genome-wide comparative analyses to other extinct and extant diurnal ratites.
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| 25. |
- Morcos, Sameh K., et al.
(author)
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Reducing the risk of iodine-based and MRI contrast media administration : recommendation for a questionnaire at the time of booking
- 2008
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In: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 66:2, s. 225-229
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Journal article (peer-reviewed)abstract
- This paper presents a practical questionnaire to be used when a contrast medium examination is requested. The questionnaire is based on the guidelines from the European Society of Urogenital Radiology. Its aim is to identify patients at increased risk of clinically relevant renal and non-renal adverse reactions to iodine-based and MRI contrast agents. The questionnaire should be completed by the referring physician when the examination is requested.
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| 26. |
- Nyman, Ulf, et al.
(author)
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Are gadolinium-based contrast media really safer than iodinated media for digital subtraction angiography in patients with azotemia?
- 2002
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In: Radiology. - : Radiological Society of North America (RSNA). - 1527-1315 .- 0033-8419. ; 223:2, s. 311-318
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Journal article (peer-reviewed)abstract
- Gadolinium chelates, intended as intravenous contrast media for magnetic resonance imaging, have been regarded as nonnephrotoxic and recommended to replace iodinated contrast media in patients with azotemia who are undergoing digital subtraction angiography (DSA). High intraarterial doses (up to 220 mmol of gadodiamide) have been used, with a 40% incidence of nephropathy. The authors discourage the use of gadolinium for DSA for several reasons. (a) There exist no randomized studies comparing the nephrotoxic effects of gadolinium-based and iodinated media at equal-attenuating concentrations and doses. (b) Gadolinium-based media are hypertonic, a pathogenetic factor in contrast medium-induced nephropathy after renal angiography, with an osmolality two to seven times that of plasma. Iodinated media in concentrations that are equally attenuating with gadolinium-based media can be made isotonic. (c) In vitro measurements indicate that 0.5 mol/L gadolinium chelates are equally attenuating with 60-80 mg iodine per milliliter at the commonly used 70-90-kV range used for DSA. Thus, 50 mL of 0.5 mol/L gadolinium chelate ( approximately 0.3 mmol/kg in an 80-kg person) would be equally attenuating with a dose of 3-4 g of iodine in an iodinated medium (eg, 50 mL iohexol at 60-80 mg I/mL or 10-13 mL at 300 mg I/mL). (d) By combining these data on attenuation and results of toxicity studies in mice, the general toxicity of gadolinium chelates may be six to 25 times higher than that of equal-attenuating doses of iodinated media at 70-kV DSA. Thus, the authors believe that at equal-attenuating doses for DSA, modern iodinated contrast media should result in a lower toxic load on the body than with presently available gadolinium chelates.
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| 27. |
- Nyman, Ulf, et al.
(author)
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Are intravenous injections of contrast media really less nephrotoxic than intra-arterial injections?
- 2012
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In: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 22:6, s. 1366-1371
-
Journal article (peer-reviewed)abstract
- We oppose the opinion that the intra-arterial administration of iodine-based contrast media (CM) appears to pose a greater risk of contrast medium-induced nephropathy (CIN) than intravenous administration since 1) in intra-arterial coronary procedures and most other intra-arterial angiographic examinations, CM injections are also intravenous relative to the kidneys, 2) there is a lack of comparative trials studying the risk of CIN between intra-arterial and intravenous procedures with matched risk factors and CM doses, 3) a bias selection of patients with fewer risk factors may explain the seemingly lower rate of CIN after CT in comparison with coronary interventions, 4) the rate of CIN following intra-arterial coronary procedures may also be exaggerated owing to other causes of acute kidney failure, such as haemodynamic instability and microembolisation, 5) roughly the same gram-iodine/GFR ratio (a parts per thousand 1:1) as a limit of relatively safe CM doses has preliminarily been found for both intravenous CT and intra-arterial coronary procedures and 6) the substantially higher injected intravenous CM dose rate during CT relative to an intra-arterial coronary procedure might actually pose a higher risk of CIN following CT. Key Points Most intra-arterial injections of contrast media are intravenous relative to the kidneys. No evidence that intravenous CM injections should be less nephrotoxic than intra-arterial. Considerably higher dose rates of CM are used for CT relative to intra-arterial procedures. Higher dose rates may pose higher nephrotoxic risk for intravenous based CT studies.
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| 28. |
- Nyman, Ulf, et al.
(author)
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Commentary on the viewpoint of Spinosa et al
- 2002
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In: Radiology. - : Radiological Society of North America (RSNA). - 1527-1315 .- 0033-8419. ; 223:2, s. 326-327
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Journal article (other academic/artistic)
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| 29. |
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| 30. |
- Nyman, U, et al.
(author)
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Contrast-medium-induced nephropathy correlated to the ratio between dose in gram iodine and estimated GFR in ml/min
- 2005
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In: Acta Radiologica. - : SAGE Publications. - 1600-0455 .- 0284-1851. ; 46:8, s. 830-842
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Journal article (peer-reviewed)abstract
- Purpose: To suggest a more precise tool when assessing the risk of contrast-medium-induced nephropathy (CIN), i.e. the ratio between contrast medium (CM) dose expressed in grams of iodine (g-I) and estimated glomerular filtration rate in ml/min (eGFR; based on equations using serum-creatinine (s-Cr), weight, height, age, and/or sex), here named I-dose/GFR ratio. Material and Methods: A Medline search of published CIN investigations reporting mean eGFR and mean dose of low-osmolality CM (LOCM) identified 10 randomized controlled prophylactic and 2 cohort coronary investigations, and 3 randomized and I cohort computed tomographic (CT) investigation. From the randomized trials, data were collected only from the placebo or control arms, unless there was no significant difference between the control and test groups. The mean I-dose/GFR ratio of each study was correlated with the mean frequency of CIN-1 (s-Cr rise >= 44.2 mu mol/l or >= 20-25%) and CIN-2 (oliguria or requiring dialysis). A maximum dose according to an I-dose/GFR ratio = 1 in patients with s-Cr ranging from 100 to 300 mu mol/l was compared with that of CIGARROA'S formula and with a "European consensus" threshold published by the European Society of Urogenital Radiology, both using s-Cr alone to predict renal function. MCCULLOUGH'S formula was used to assess the risk of CIN requiring dialysis at an I-dose/GFR ratio=1 with LOCM. Results: The coronary investigations revealed a linear correlation with a correlation coefficient between the I-dose/GFR ratio and the frequency of CIN-1 and CIN-2 of 0.91 (P<0.001) and 0.84 (P=0.001), respectively. At a mean I-dose/GFR ratio=1, the regression line indicated a 10% risk of CIN-1 and a 1% risk of CIN-2. At a mean I-dose/ GFR ratio=3, the risk of CIN-1 and CIN-2 increased to about 50% and 15%, respectively. Pooled weighted data from the CT investigations revealed a 12% risk of CIN-1 at a mean I-dose/GFR ratio = 1.1 and no cases of CIN-2. The maximum CM dose according to an I-dose/GFR ratio=1 was about 30-50% of that of both CIGARROA'S formula and the "European consensus" in elderly low-weight individuals, while it was similar for middle-aged individuals weighing about 90 kg. MCCULLOUGH'S formula suggests that there will be an exponentially increasing risk of CIN requiring dialysis, but at an I-dose/GFR ratio = 1 and using LOCM it will not exceed 1% until GFR decreases below 30 ml/min in diabetics and below 20 ml/min in non-diabetics. Conclusion: Using the I-dose/GFR ratio may be a more expedient way of improving risk assessment of CIN than today's common practice of estimating CM dose from volume alone and renal function from s-Cr alone. Prospective studies based on individual patient data are encouraged to define the risk of CIN at various I-dose/GFR ratios and correlated to type of CM, examination, risk factors, etc.
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| 31. |
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| 32. |
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| 33. |
- Nyman, Ulf, et al.
(author)
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Iodine contrast iso-attenuating with diagnostic gadolinium doses in CTA and angiography results in ultra-low iodine doses. A way to avoid both CIN and NSF in azotemic patients?
- 2011
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In: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 21, s. 326-336
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: To establish iodine (I) contrast medium (CM) doses iso-attenuating with gadolinium (Gd) CM doses regarded diagnostic in CTA and percutaneous catheter-angiography/vascular interventions (PCA/PVI) in azotemic patients. METHODS: CT Hounsfield units (HU) were measured in 20-mL syringes containing 0.01/0.02,/0.05/0.1 mmol/mL of iodine or gadolinium atoms and placed in phantoms. Relative contrast were measured in 20-mL syringes filled with iohexol at 35/50/70/90/110/140 mg I/mL and 0.5 M gadodiamide using radiofluoroscopy (RF), digital radiography (DX) and x-ray angiography (XA) systems. Clinical doses of Gd-CM at CTA/PCA/PVI were reviewed. RESULTS: At CT 91-116 and 104-125 mg I/mL in the chest and abdominal phantoms, respectively, were iso-attenuating with 0.5 M Gd at 80-140 kVp. At RF/DX/XA systems 35-90 mg I/mL were iso-attenuating with 0.5 M gadodiamide at 60-115 kVp. Clinically, 60 mL 91-125 mg I/mL (5.5-7.5 gram-iodine) at 80-140 kVp CTA and 60 mL of 35-90 mg I/mL (2.1-5.4 gram-iodine) at 60-115 kVp PCA/PVI would be iso-attenuating with 60 mL 0.5 M Gd-CM (=0.4 mmol Gd/kg in a 75-kg person). CONCLUSIONS: Meticulous examination technique and judicious use of ultra-low I-CM doses iso-attenuating with diagnostic Gd-CM doses in CTA and PCA/PVI may minimise the risk of nephrotoxicity in azotemic patients, while there is no risk of NSF.
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| 34. |
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| 35. |
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| 36. |
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| 37. |
- Sterner, Gunnar, et al.
(author)
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Determining 'true' glomerular filtration rate in healthy adults using infusion of inulin and comparing it with values obtained using other clearance techniques or prediction equations.
- 2008
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In: Scandinavian Journal of Urology and Nephrology. - : Informa UK Limited. - 0036-5599 .- 1651-2065. ; 42:3, s. 278-285
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Journal article (peer-reviewed)abstract
- Objective. To determine 'true' glomerular filtration rate (GFR) in healthy adults as renal clearance following infusion of inulin, and compare that result with those obtained using other markers and clearance techniques and with estimations of GFR using creatinine-based prediction equations. Material and methods. Twenty healthy volunteers (11 females) with a median age of 27 years (range 19-36 years) received bolus doses of inulin and iohexol i.v. and 16 blood samples were taken after injection. Then, inulin and iohexol were infused to give stable plasma concentrations and blood and urine samples were collected. Residual bladder volume was estimated using ultrasound scanning. Plasma and urine concentrations of inulin and iohexol were determined using chromatography and resorcinol methods, respectively. Different methods of GFR determination were compared as well as four formulae for GFR estimation based on serum creatinine. Results. 'True' GFR, i.e. renal clearance of inulin during its infusion, was a median of 117 ml/min/1.73 m2 (inter-quartile range 106-129 ml/min/1.73 m2). Similar values of GFR were obtained with renal clearance of iohexol during its infusion and also with plasma (body) clearance of inulin or iohexol following bolus injections and using 16 or five plasma samples. Endogenous creatinine clearance was higher (p<0.001) than true GFR (median 23 ml/min/1.73 m2). Plasma clearance of iohexol and inulin based on their concentrations in four blood samples underestimated their renal clearance considerably. All four creatinine-based formulae markedly underestimated renal inulin clearance. Conclusions. Plasma and renal clearance of iohexol and inulin were similar in healthy adults. Underestimation of GFR was noted when plasma clearance of iohexol and inulin was based on four but not five or more blood samples. Some prediction equations underestimate true GFR to such an extent that caution must be taken when using them to evaluate normal or high GFR values.
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| 38. |
- Ståhlbrandt, Henriettæ, et al.
(author)
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CT and MRI imaging in Sweden: retrospective appropriateness analysis of large referral samples
- 2023
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In: Insights into Imaging. - 1869-4101. ; 14, s. 1-9
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Journal article (peer-reviewed)abstract
- ObjectivesThe numbers of computed tomography (CT) and magnetic resonance imaging (MRI) examinations per capita continue to increase in Sweden and in other parts of Europe. The appropriateness of CT and MRI examinations was audited using established European appropriateness criteria. Alternative modalities were also explored. The results were compared with those of a previous study performed in Sweden.MethodsA semi-automatic retrospective evaluation of referrals from examinations performed in four healthcare regions using the European appropriateness criteria in ESR iGuide was undertaken. The clinical indications from a total of 13,075 referrals were assessed against these criteria. The ESR iGuide was used to identify alternative modalities resulting in a higher degree of appropriateness. A qualitative comparison with re-evaluated results from the previous study was made.ResultsThe appropriateness was higher for MRI examinations than for CT examinations with procedures classed as usually appropriate for 76% and 63% of the examinations, respectively. The degree of appropriateness for CT was higher for referrals from hospitals compared to those from primary care centres. The opposite was found for MRI examinations. The alternative modalities that would result in higher appropriateness included all main imaging modalities. The result for CT did not show improvement compared with the former study.ConclusionsA high proportion of both CT and MRI examinations were inappropriate. The study indicates that 37% of CT examinations and 24% of MRI examinations were inappropriate and that the appropriateness for CT has not improved in the last 15 years.Critical relevance statementA high proportion of CT and MRI examinations in this retrospective study using evidence-based referral guidelines were inappropriate.Key points∙ A high proportion of CT and MRI examinations were inappropriate.∙ The CT referrals from general practitioners were less appropriate that those from hospital specialists.∙ The MRI referrals from hospital specialists were less appropriate that those from general practitioners.∙ Adherence to radiological appropriateness guidelines may improve the appropriateness of conducted examinations.
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| 39. |
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| 40. |
- Thomsen, Henrik S., et al.
(author)
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Nephrogenic systemic fibrosis and gadolinium-based contrast media: updated ESUR Contrast Medium Safety Committee guidelines
- 2013
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In: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 23:2, s. 307-318
-
Journal article (peer-reviewed)abstract
- To update the guidelines of the Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) on nephrogenic systemic fibrosis and gadolinium-based contrast media. Topics reviewed include the history, clinical features and prevalence of nephrogenic systemic fibrosis and the current understanding of its pathophysiology. The risk factors for NSF are discussed and prophylactic measures are recommended. The stability of the different gadolinium-based contrast media and the potential long-term effects of gadolinium in the body have also been reviewed. aEuro cent Clinical features, risk factors and prevention of nephrogenic systemic fibrosis are reviewed aEuro cent Patients with GFR below 30 ml/min/1.73 m (2) have increased risk of developing NSF aEuro cent Low stability gadolinium contrast media show the strongest association with NSF aEuro cent Following guidelines regarding gadolinium contrast agents minimises the risk of NSF aEuro cent Potential long-term harm from gadolinium accumulation in the body is discussed.
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| 41. |
- van Westen, Danielle, et al.
(author)
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Biliary and total extrarenal clearance of inulin and iohexol in pigs. A source of error when determining gfr as body clearance.
- 2002
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In: Nephron. - : S. Karger AG. - 0028-2766 .- 1660-8151 .- 2235-3186. ; 91:2, s. 300-307
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Journal article (peer-reviewed)abstract
- Biliary clearance, total extrarenal clearance, body and renal clearance of inulin and iohexol were determined in 11 normal and 11 nephrectomized pigs. The biliary clearance of inulin, calculated as biliary excretion divided by the plasma concentration, was 0.04 and 0.01 ml min<sup>–1</sup> 10 kg<sup>–1</sup> and of iohexol 0.21 and 0.1 ml min<sup>–1</sup> 10 kg<sup>–1</sup> , in normal, respectively, nephrectomized pigs (p < 0.05). The extrarenal clearance of inulin, calculated as body minus renal clearance, was 2.7 and 0.7 ml min<sup>–1</sup> 10 kg<sup>–1</sup> and of iohexol 3.7 and 0.7 ml min<sup>–1</sup> 10 kg<sup>–1</sup> in normal, respectively, nephrectomized pigs (p < 0.05). Some hours after injection of the markers their plasma concentrations were much higher in the nephrectomized pigs. This higher plasma concentration was not matched by an equally higher biliary excretion and therefore biliary clearance decreased. The smaller total extrarenal clearance in nephrectomized pigs, i.e. the overestimation of GFR when calculated as body clearance, indicates that this source of error decreases with decreasing renal function.
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| 42. |
- Wikström, Andreas, et al.
(author)
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Bottentrålning och resuspension av sediment : Bottom trawling and resuspension of sediment
- 2016
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Reports (other academic/artistic)abstract
- Bakgrundsvärden av suspenderat material i Koster-Väderöfjorden varierar. Halterna av suspenderat material höjs under dagar med trålning. Höjningen av suspenderat material kan i de trålade vattenmassorna vara så hög att den under kortare perioder når nivåer som visat sig vara negativa för vissa organismer. Resuspension av material från trålning kan leda till förhöjda bakgrundsnivåer av suspenderat material. Små skyddsområden kan minska spridningen av resuspension för stora partiklar men inte för små till medelstora partiklar.
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