Nonionic Agents Research Articles

Swelling-induced O −2 generation in guinea-pig neutrophils

Without the addition of any exogenous stimuli, neutrophils generated O − 2 and then ceased in a reversible manner that correlated with cellular swelling and contraction. The nature of the possible mechanism responsible for this O − 2 generation was studied and compared with that observed in the triggering of stimulant-dependent O − 2 generation (respiratory burst). The swelling-induced O − 2 generation was inhibited by diphenyliodonium, and was independent of the functional distortion of mitochondrial and/or microsomal electron transport and xanthine oxidase. This suggested that such generation was involved in respiratory-burst oxidase activation; however, this generation was not accompanied by any new phosphorylation of the 47-kDa protein or of tyrosine proteins. Dihydrocytochalasin B potentiated the O − 2 generation. The cellular swelling produced a priming effect on the triggering of respiratory burst with different stimuli. Cellular contraction, conversely, suppressed the respiratory burst. The structural specificity of the swelling-induced plasma membrane modulation for the O − 2 generation was suggested by the finding that modulation of plasma membrane structures by various non-ionic detergents per se inhibited O − 2 generation. Lipophilic and positively-charged agents inhibited the generation and this inhibition was abrogated by negatively-charged, but not by non-ionic agents. Negatively-charged agents potentiated the O − 2 generation. These results suggest that both the interaction of the plasma membrane with the cytoskeleton and an increase in net negative charges at the plasma membrane play important role in evoking O − 2 generation; this is discussed and compared with the signal transduction reported previously for respiratory burst.

Patient Choice and Nonionic Contrast Media

Because of the greatly increased cost of nonionic, low-osmolar contrast material, some practitioners reserve its use for patients at high risk for an adverse contrast reaction. The authors attempt to evaluate the proportion of low-risk outpatients--when offered a choice between the more expensive but lower-risk nonionic and the cheaper but higher-risk conventional ionic contrast material--that would choose the nonionic media. Two hundred and fifty consecutive outpatients awaiting contrast-enhanced computed tomography were included in this study. Patients at increased risk for a contrast reaction were excluded. The remaining 162 patients were informed of the risks and told of the availability of nonionic contrast media with its up to six-fold decrease in serious complications. They were also informed that if they chose the lower-risk nonionic agent, they would likely have to pay the additional $100 to $150 in cost. Of the 162 low-risk patients surveyed, 48% selected nonionic contrast media, and 63% believed that all patients should be informed of the risks of contrast material and of the availability of nonionic contrast. The data support providing patients at low risk for an adverse reaction informed consent about the relative risks of ionic and nonionic contrast material.

Contrast material for combined abdominal and pelvic CT: can cost be reduced by increasing the concentration and decreasing the volume?

The purpose of this study was to determine if enhancement provided by a smaller volume of a more concentrated nonionic contrast agent is equivalent to that provided by a larger volume of a less concentrated nonionic agent on dynamic, incremental abdominal and pelvic CT. During a 4-month period, 168 patients undergoing dynamic incremental abdominal and pelvic CT received 150 ml iopamidol-300 (45 g iodine). During the following 4 months, 119 patients received 125 ml ioversol-320 (40 g iodine). The same automated injector and scanning parameters were used for both groups. Absolute enhancement of the liver at three levels and of abdominal and pelvic vessels was calculated and analyzed by using Student's t-test. Arterial and venous enhancement in the upper part of the abdomen, at the level of the iliac crest, or in the pelvis was not significantly different with the two contrast agents. Both ioversol and iopamidol provided the same mean enhancement of the hepatic parenchyma at the level of the hepatic veins (45 H) and at the level of the portal vein (49 H). At the level of the gallbladder fossa, enhancement of liver parenchyma with the two contrast agents was significantly different (p = .04): mean enhancement was 45 H for iopamidol and 42 H for ioversol. A retrospective analysis of the liver enhancement profiles from 50 randomly selected patients from each group showed no significant difference in parenchymal enhancement. For dynamic abdominal and pelvic CT, no statistically significant difference was found between the mean enhancement of the liver and abdominal vessels after administration of 125 ml of ioversol-320 and that after administration of 150 ml of iopamidol-300. Therefore, 125 ml of ioversol-320 can be used instead of 150 ml of iopamidol-300 without compromising image quality. At current prices, this will result in savings of approximately 18% per patient.

Effects of an ionic versus a nonionic low osmolar contrast agent on the thrombotic complications of coronary angioplasty

An increasing body of evidence suggests that the potential for thrombotic complications is greater with nonionic than with ionic contrast agents. This is a particularly important consideration in the highly thrombogenic setting of percutaneous transluminal coronary angioplasty (PTCA). To explore this issue further, 500 consecutive patients undergoing PTCA were prospectively randomized to receive the low osmolality ionic ioxaglate or the nonionic agent iohexol. The number of acute thrombotic in-laboratory events was significantly less in the ioxaglate than in the iohexol group (8 versus 18; P < 0.05), but there was no significant difference between the 2 groups as regards the number of out-of-laboratory acute rethrombotic events. With multivariate analysis, use of the nonionic agent rather than the ionic agent emerged as an independent predictor of acute in-laboratory rethrombosis. These data suggest that, in the performance of PTCA, an ionic, rather than a nonionic, should be the preferred contrast agent.

Use of nonionic or low osmolar contrast agents in cardiovascular procedures

Low osmolar contrast agents produce less adverse electrophysiologic and hemodynamic alterations during cardiac catheterization. The nonionic agents probably reduce the risk of provoking myocardial ischemia during coronary arteriography or ventriculography. Patients also report less subjective sensation of discomfort during administration of low osmolar agents for cardiovascular procedures. However, nonionic agents have not been proved to reduce the incidence of several serious complications of cardiac catheterization, including acute renal failure and anaphylactoid reaction. Although evidence is inconclusive, there may be an increased risk of thromboembolic complications during cardiac catheterization when certain low osmolar nonionic agents are administered. Nonionic contrast agents have not been definitely proved to reduce the risk of death after cardiac catheterization.

Improved compatibility of disperse dye mixtures using levelling agent—assessment through hue angle measurement

The compatibility of a mixture of disperse dyes in equal proportions having similar hues (all in the red‐yellow quadrant of the colour space) has been assessed at different applied depths on polyester fabric, with and without levelling agent, using plots of hue angle against KIS values. The plots were found to be useful in indicating the improvement in the compatibility of dyes at higher applied depths attributable to the addition of a nonionic levelling agent.

メチル3-O-アルキルグルコピラノシドの合成と抗菌性

A new type of nonionic surface-active agents containing sugars as the hydrophilic group were synthesized and evaluated for their antimicrobial activity. Methyl 6-deoxy-3-O-dodecyl-6-halo-D-glucopyranoside derivatives showed powerful antimicrobial activity, but no significant differences were observed on the activity with regard to the kinds of anomers as well as halogen atoms.

Delineation of acute myocardial infarction with dysprosium DTPA-BMA: Influence of dose of magnetic susceptibility contrast medium

Objectives. The contrast enhancement of acutely infarcted myocardium produced by the nonionic magnetic susceptibility-enhancing agent dysprosium diethylenetriamine pentaacelic acid-bis-methylamide (DyDTPA-BMA [S-043 Injection]) was assessed in the current study to establish the lowest dose that would yield optimal contrast between normal and acutely infarcted myocardium.Background. Magnetic susceptibility contrast agents enhance differences between normal and ischemic tissue by reducing the signal of the normally perfused tissue to which they distribute.Methods. Acute myocardial infarctions were produced by ligation of the left coronary artery. At 3 to 4 h after occlusion, a dose of 0.1, 0.3 or 0.5 mmol/kg of DyDTPA-BMA was injected intravenously into eight rats each in group 1, 2 or 3, respectively; a fourth group of seven rats served as a control group. Nuclear magnetic resonance (NMR) transverse relaxation time (T2)-weighted images (electrocardiographically gated to every 5th beat, echo delay time [TE]= 60 ms) were acquired before and for 1 h after administration of contrast agent.Results, Images obtained before the injection of contrast agent showed moderate differences in signal intensity between normal and infarcted myocardium (p < 0.05). The contrast enhancement and the duration of delineation between infarcted and normal myocardium produced by this agent were dose dependent. At doses of 0.1, 0.3 and 0.5 mmol/kg, DyDTPA-BMA produced signal loss in normal myocardium: 63 ± 5%, 41 ± 4% and 28 ± 4% of the baseline values, respectively, without any significant reduction in signal intensity of the infarcted region. The reduction in signal of normal myocardium and delineation of the infarct persisted for 5 min at a dose of 0.1 mmol/kg, for 20 min at a dose of 0.3 mmol/kg and for 40 min at a dose of 0.5 mmol/kg. No change in signal intensity or signal intensity ratio between normal and infarcted myocardium was observed in the control group during the same observation period.Conclusions. These results suggest that low doses of this agent, comparable to those of longitudinal relaxation time (T1)-enhancing agents, can delineate acutely infarcted myocardium. A dose of 0.3 mmol/kg of DyDTPA-BMA (S-043 Injection) provides reasonably persistent demarcation of acute myocardial infarction. Because this dose dramatically suppresses the NMR signal of normal myocardium, it shows the infarcted region as a region of high intensity (bright spot) on NMR images.

Passive Blood/Contrast Agent Exchange in Angiographic Catheters and Its Effects on Platelets

A static column of contrast agent or saline in an angiographic catheter will passively exchange with blood during angiography. The authors investigated the time course of this exchange in 5.5- and 7-F polyethylene catheters inclined at various angles. Passive blood exchange occurred 2 cm into the catheters within 7-15 seconds at most catheter tip angles, except for those catheters oriented so that their tips were nearly horizontal. In a separate series of experiments, the effect of contrast agent on platelet function and blood clotting was analyzed. The agent was sufficiently diluted in blood so as to simulate an angiographic procedure. The studies were performed in 60 cylindrical polyethylene containers with both unheparinized and heparinized blood. Use of an ionic contrast agent, more than a nonionic agent, lengthened the time for platelet aggregation (mean increases for ionic vs nonionic agents were 46.4 and 37.1 seconds, for unheparinized and heparinized blood, respectively), platelet adhesion to polyethylene surfaces (mean increases, 46.0 and 64.2 seconds), and platelet-stimulated coagulation (mean increases, 38.5 and 43.9 seconds). Conventional, intermittent flushing with saline or filling the catheter with contrast agent may be insufficient to prevent blood from rapidly back-filling the catheter tips. Contrast agents (ionic more than nonionic) distributed in the patient's blood volume inhibit platelet coating of catheter lumens and/or blood clotting under such circumstances.

Contractile, metabolic and arrhythmogenic effects of ionic and nonionic contrast agents in the isolated rat heart

Intracoronary administration of contrast agents may be associated with contractile dysfunction and arrhythmias. To further establish the mechanisms of these alterations, we studied high-energy phosphate metabolism, developed pressure, the occurrence of arrhythmias, and the effects of verapamil during infusion of ionic and nonionic agents in isovolumic, retrogradely perfused rat hearts using 31P nuclear magnetic resonance imaging (NMR). Diatrizoate meglumine (Renografin) infusion reduced developed pressure (DP) to 17.1 ± 3.4% ( p < 0.001) of the control level, and immediately following termination of the infusion, sudden ventricular tachycardia (VT) was observed in four of six hearts. In the presence of verapamil, meglumine reduced DP to 13 ± 1.9% of control values and none of these six hearts developed VT. Iopamidol infusion in the presence of verapamil ( n = 6) and alone ( n = 6) resulted in a decrease in DP to 87% of control value, and no arrhythmias, significant change in high-energy phosphate levels, or changes in pH were observed. These results suggest that contrast-induced contractile depression is not mediated by changes in high-energy phosphate metabolism or pH. Arrhythmias associated with meglumine administration alone and suppressed by verapamil are probably related to calcium loading.

Improving the compatibility of disperse dye mixtures using levelling agent — assessment through colour coordinates

The addition of a nonionic levelling agent to a dyebath containing a mixture of three disperse dyes in equal proportions and having similar hues (all in the red—yellow sector of colour space) significantly improved their compatibility, especially at higher applied depths of 3.0% and 4.5%. The dyed samples were measured for the differences in their colour coordinates with respect to the undyed substrate on a spectrophotometer attached to an IBM personal computer. The plots of ΔL* vs ΔC*ab, ΔL* vs K/S, Δb* vs Δa*, Δa* vs K/S and Δ6* vs K/S clearly indicated the improvement in compatibility of the dye mixture.

Adverse reactions to non-ionic contrast media with special regard to high-risk patients

Non-ionic contrast media (CM) are proven to be significantly safer than the high osmolar ionic contrast media (HOCM). Nevertheless deaths are reported after administration of non-ionic agents. The aim of the study was to investigate the rate of adverse reactions to non-ionic CM with special regard to high-risk patients and the effects of premedication with H1-and H2-receptor antagonists. In a prospective study conducted over about 2 years 12 995 examinations with intravenous or intra-arterial non-ionic CM were evaluated. Premedication with H1-and H2-antagonists was used in 1276 high-risk patients with known adverse reaction to CM, history of allergy or severe cardiac or pulmonary disease. 229 patients received no premedication inspite of known risk factors. In total, there were 143 (1.10%) adverse reactions (mild in 0.58%, moderate in 0.41% and severe in 0.05%). In high-risk patients there were adverse reactions in 4.37% without and in 1.57% with premedication. There were no severe adverse reactions in the high-risk patients after premedication. The age of the patient, CM dosage and CM concentration were not shown to be risk factors in the present study. In conclusion, the additional premedication with H1- and H2-antagonists could be an effective agent to reduce the risk of mild and moderate adverse reactions and to avoid severe adverse reactions in high-risk patients.

Radiocontrast agents induce endothelin release in vivo and in vitro.

The intravascular administration of the ionic radiocontrast agent sodium iothalamate (2.9 g of iodine/kg body wt) to rats induced an increase in plasma concentration of immunoreactive endothelin from 21.3 +/- 1.2 to 36 +/- 3 fmol/mL, preceded by a transient rise in the plasma level of atrial natriuretic peptide and associated with a fall in RBF. Equi-iodine amounts of the nonionic agents ioxaglate and iohexol elicited similar or more marked changes in plasma endothelin, but hypertonic solutions of NaCl, mannitol, or glucose did not. Comparable levels of endothelin produced by infusions of endothelin-1 induced a reduction of up to 29% in RBF. Iothalamate and iohexol stimulated endothelin release from cultured bovine endothelial cells, suggesting a direct effect of ionic and nonionic agents on vascular endothelium. The data invite speculation that under some circumstances endothelin release might play a role in the circulatory changes caused by these compounds and in the pathogenesis of radiocontrast nephropathy.

Comparative trial of Omnipaque 350 (iohexol) and Telebrix 350 (sodium-meglumine-ioxithalamate) in left ventriculography and coronary arteriography

In a double-blind randomized trial, the hemodynamic and electrophysiologic effects of the low-osmolar nonionic contrast medium iohexol (Omnipaque) and the standard high-osmolar ionic monomer sodium-meglumine-ioxithalamate (Telebrix) at left ventricular angiography and selective coronary arteriography were evaluated. Sixty patients were divided into two groups of 30 patients; one group received Omnipaque in a dosage of 350 mgI/ml and the other group received Telebrix in a dosage of 350 mgI/ml. The Omnipaque showed significantly less effects on heart rate and myocardial contractility, and induced less electrophysiological changes than did Telebrix. However, there was a significant increase of 10% in the diameter of the left coronary artery following selective coronary injection with Telebrix, while Omnipaque induced practically no change in vessel diameter. All hemodynamic and electrophysiologic effects proved to be short-lasting. We conclude that ionic and nonionic agents are similarly efficacious in providing adequate images with minimal risk to the patient. However, the nonionic agents exert slightly more alterations in cardiac hemodynamics and in electrocardiographic intervals. The vasodilatory effect on coronary artery diameter by Telebrix may entail a more rapid clearance of contrast medium from the coronary circulation, which might be of some advantage over nonionic contrast media.

Synthesis of linear 1- 0-dodecylglycerol ethers using allylglycidyl ethers as a diglycerol equivalent.

Synthesis of the nonionic surface active agents ( 1) and ( 2) is described. The scheme uses allyl-glycidyl ether as a diglycerol equivalent circumventing the use of the highly toxic epichlorohydrin.

Fibrin modification by ionic and nonionic contrast media during cardiac catheterization

T he rare but serious complication of thromboembolism during cardiac catheterization is believed to be a result of an imbalance between the prothrombotic nature of the invasive procedure and the antithrombotic effects of adequate catheter flushing and of the contrast agents themselves. Although thrombotic complications may occur as a result of an identifiable problem in procedural technique, thrombosis sometimes occurs without explanation.’ Both ionic and nonionic contrast media are known to have an inhibitory effect on platelet aggregation and blood clotting in vitro2-9; however, nonionic contrast has been shown to have a less inhibitory effect,3-5*7-9 and therefore could theoretically result in a greater tendency for thrombosis.tO Hwang et al” showed that use of the nonionic agents iohexol and iopamidol was associated with coronary thromboembolism during cardiac catheterization in dogs, whereas the ionic agents ioxaglate and diatrizoate were not associated with such clotting complications. It has also been observed that clots embolized into coronary arteries during catheterization are particularly difficult to dissolve with thrombolytic therapy.t2 Both the ionic contrast agent diatrizoate and the nonionic agent iopamidol have been shown in vitro to cause changes in fibrin assembly and structure, resulting in thin fibrin fibrils,6 which render the fibrin resistant to fibrinolysis. Fibrin with low mass/length ratio in certain disease states has been shown to be resistant to fibrinolysis.13 Demonstration of fibrin changes in vivo during cardiac catheterization would provide further evidence that the in vitro changes have clinical relevance, including providing a possible explanation for why contrast-induced thrombus is resistant to fibrinolysis. This study evaluates the effects of ionic and nonionic contrast media on fibrin assembly and structure by analyzing samples obtained at critical times and anatomic locations during cardiac catheterization. Twenty-three patients undergoing cardiac catheterization between March 14,1990, and July 12,1990, were prospectively studied. Exclusion criteria were as follows: history of bleeding disorder, hypercoagulable state, treatment with warfarin or heparin, hematocrit <30%, platelet count <150,000, abnormally elevated protime or partial thromboplastin time, uncontrolled angina at rest, or myocardial infarction within 3 months. The indication for cardiac catheterization was suspicion of coronary artery disease due to chest pain or a positive func-

Comparison of iohexol 300 and diatrizoate meglumine 60 for body CT: image quality, adverse reactions, and aborted/repeated examinations.

Six hundred patients were prospectively randomized and given either diatrizoate meglumine 60 or iohexol 300 during dynamic contrast-enhanced body CT in order to compare image quality, contrast reactions, and the number of aborted studies or studies in which images had to be repeated. Three hundred two patients received iohexol 300, and 298 patients received diatrizoate meglumine 60. Thirty-nine percent (119/302) of the patients given iohexol 300 and 63% (188/298) of the patients given diatrizoate meglumine 60 had at least one adverse reaction thought to be related to contrast material during, or within 24 hr of, the body CT scan. When reactions of discomfort (heat or warmth, flushing, bad taste) were excluded, 16% (48/302) of the patients who received iohexol and 33% (99/298) of the patients who were given diatrizoate meglumine 60 had at least one adverse reaction. The differences in both types of reactions between the two agents were significant (p less than .001). Among scans evaluated for study quality, 71% (214/302) of the iohexol 300 group and 62% (184/298) of the diatrizoate meglumine 60 group had optimal enhancement (p = .02). However, when the optimal and adequate categories were combined, 301 of 302 patients given iohexol 300 and 292 of 298 patients given diatrizoate meglumine 60 had diagnostic-quality studies (no statistical difference). Studies were not terminated nor were images repeated in 97% (292/302) of the patients given iohexol 300 and in 94% (280/298) of those given diatrizoate meglumine 60. The CT study was repeated because of movement during the contrast injection or aborted because of contrast-related reactions in 0.7% of the patients given iohexol 300 and in 3.0% of the patients given diatrizoate meglumine 60. This difference was statistically significant (p = .04). Our results suggest that the difference in image quality, number of adverse reactions, and number of aborted/repeated CT scans performed with iohexol 300 or diatrizoate meglumine 60 are not sufficiently different to warrant conversion to nonionic agents for body CT scans.

Relationship of anticoagulation and radiographic contrast agents to thrombosis during coronary angiography and angioplasty: Are there real concerns?

Radiographic contrast agents are essential for the performance of coronary angiography and angioplasty. Historical data show that thrombosis-related events have occurred since coronary angiography has been performed. Newer non-ionic agents have been shown to be safer than conventional high osmolar ionic agents especially in high risk patients, but concern has been raised about a potentially increased risk of thrombosis with the use of these agents. A review of basic and clinical evidence for this perception does not support the view that an increase in thrombosis-related events has occurred as a results of non-ionic contrast media use in coronary angiographic procedures.

Paper Chromatographic Observation on the Effects of Surface Active Agents to Remove the Soil on Fiber Assemblies

Paper chromatography was conducted for examination of the physico-chemical effects of detergents for removing water insoluble soils on fiber assemblies without mechanical and/or hydrodynamic force. Using cellulose filter paper as the fiber assembly for the fixed phase and C.I. Disperse Blue 3 as a model of water insoluble soil, the relation between Rf' and the concentrations of surface active agents was examined.The Rf', a measure of detergency, increased steeply near a critical micellar concentration of each surface active agent. In such a case, the longer the chain length of the alkyl group in the alkylsulfate, the lower was the concentration necessary to increase Rf' to give higher detergency. In dodecyl poly (oxyethylene) ethers, the shorter the chain length of the oxyethylene group, the lower was the concentration needed to increase Rf'. On adding NaCl to an aqueous solution of sodium dodecyl sulfate (SDS), the SDS concentration required to increase Rf' was lowered by the builder effect. Ionic surface active agents showed lower Rf' at higher temperature, while nonionic agents showed higher Rf' at high temperature.By application of a theoretical equation to pseudophase liquid chromatography, the detergency of Disperse Blue 3 as a model of soils could be explained on the basis of the solubilization mechanism.

Enhanced Bleaching and Softening of Jute by Pretreatment with Polysaccharide Degrading Enzymes

The brightness of peroxide bleached jute material increased by about 3% when pretreated with an enzyme mix containing cellulase and xylanase. Pretreatment for 6 hours at pH 5.0 and 45°C using 0.2 u (unit) cellulase and 2.6 u of xylanase per gram of fibers gave the best results. Additives like nonionic surfactants or chelating agents during pretreatment further enhanced the brightness. Pretreatment reduced the per oxide requirement for bleaching and rendered the jute materials distinctly softer.