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At least 685 records · Page 38Linked to original sources
PubMed1986

Contrast media tonicity. Part I. Effects upon IV-DSA time-concentration curve peak and width: experimental studies.

Prior to the formation of an intravenous digital subtraction angiography (IV-DSA) image, contrast medium passes through the lesser circulation and is diluted by the blood volume of the heart and lungs. If the contrast medium alone influences central blood volume or cardiac output, the shape of the resultant time-concentration curve may be degraded. To the extent that contrast medium tonicity reduces curve peak or increases width, image quality for mask mode IV-DSA will suffer. To quantify the effect of contrast medium tonicity upon curve shape, contrast medium (1) at increasing iodine concentration and increasing osmolality and (2) at constant iodine concentration and increasing osmolality was injected into the right atria of mongrel dogs. In both experiments, increasing osmolality was associated with an increase in central blood volume (CBV) and cardiac output. With an increase in CBV, curve peak fell. With an increase in both CBV and cardiac output, curve width was not influenced by increasing osmolality. The effect of osmolality upon CBV was highly variable; in these experiments CBV was influenced more by subject-to-subject variability. However, on the average, higher tonicity contrast media produced curves with lower peaks. These studies suggest that isotonic contrast medium does not increase CBV and that isotonic contrast medium is preferable to hypertonic contrast medium for IV-DSA image formation.

Angiography↗
PubMed1986

Effect of various contrast media on coagulation, fibrinolysis, and platelet function. An in vitro and in vivo study.

An in vitro and in vivo study of the effect of ionic and nonionic contrast media (CM) on coagulation and platelet function is reported. The methods employed were tests for extrinsic and intrinsic coagulation together with a fibrinolytic parameter and aggregation using ADP and collagen as inducers. The in vivo study utilized patients undergoing routine cerebral angiography. The in vitro results showed a modest influence of the nonionic CM in contrast to the ionic. The marked inhibitory effect of the latter was mainly caused by inherent toxicity, osmolality/ionic strength being of minor importance. The in vivo results showed a negligible influence of CM on systemic hemostatic parameters, but catheter-derived samples indicated desirability of premedication with ASA or heparin. The nonionic CM caused less discomfort than the ionic CM.

Blood Coagulation↗
PubMed1987

Brain beta-endorphin and spinal-cord enkephalin concentrations in experimental arachnoiditis.

Arachnoiditis was produced experimentally in male albino ICR mice by intrathecal injection of meglumine iocarmate . A control group received intrathecal injection of an electrolyte solution resembling CSF. Eight weeks after injection, the brains and spinal cords were removed for brain beta-endorphin and spinal cord met-enkephalin measurement by radioimmunoassay, and the dural sacs were removed for histologic examination to confirm the presence or absence of arachnoiditis. Brain beta-endorphin content was significantly reduced and spinal-cord enkephalin concentration was significantly elevated in iocarmate-treated animals. The dura and arachnoid in the treated mice were thickened and infiltrated with lymphocytes. These studies indicate that arachnoiditis alters endogenous polypeptide concentrations.

Animals↗
PubMed1988

Tolerability of hypertonic and isotonic contrast media injected intravenously. A comparative study in the dog.

We examined the use of isotonic and hypertonic contrast media injected intravenously in the dog from the standpoint of cardiovascular tolerance after right atrial injections performed at 2.56 and 5.12 g I/second. The parameters measured were lead II of the electrocardiograph, heart rate, pulmonary and abdominal arterial pressure, and aortic flow. Three contrast media, ioxitalamate, ioxaglate, and iopamidol (two ionic and one nonionic), were compared, either concentrated (32% iodine) or dilute and isotonic with plasma (ioxaglate 160 mg I/mL and iopamidol 128 mg I/mL). At an injection rate of 5.12 g I/second, iopamidol-128 showed lower electrophysiologic tolerability and caused a higher increase in aortic flow than ioxitalamate 160 or ioxaglate 160. These effects may explain the lower radiographic efficacy observed with iopamidol-128 in previous digital subtraction angiography studies.

Angiography↗
PubMed1988

Vicarious excretion of water-soluble contrast media into the gallbladder in patients with normal serum creatinine.

Ten patients with normal serum creatinine and no evidence of acute cholecystitis were found to have vicarious excretion of water-soluble contrast media into the gallbladder 20 minutes to 72 hours after injection. Eight of the ten had unilateral renal pathology. Two patients, however, had bilaterally normal kidneys. The patients had been injected with either diatrizoate, iothalamate, or iodamide. The mechanisms and pathophysiology of vicarious contrast excretion are discussed. The vicarious excretion of intravascular contrast in the gallbladder does not in itself indicate renal or hepatobiliary disease. Although commonly associated with unilateral renal pathology, vicarious gallbladder excretion of urographic contrast may be a normal variant in some patients.

Adolescent↗
PubMed1988

Clinical survey of adverse reactions to contrast media.

From October 1983 to June 1986, 33,400 individuals participated in a clinical survey of adverse reactions to conventional high osmolar contrast media. The frequency of reactions was 7.5% (2,523/33,400). No fatal cases resulted. In patients pretesting positive, the incidence of adverse reactions was 48%. In individuals with a positive history of allergy, the incidence of the reactions was 52%. There was no correlation between the incidence of reactions and the presence or absence of a history of previous contrast media administration. The value of pretesting can not be negated from the present results.

Contrast Media↗
PubMed1988

Biochemical aspects on adverse reactions to contrast media. Changes of kininogen levels in dog plasma after intravenous injections of iohexol, iopamidol, and iothalamate.

The adverse reactions to contrast media have been investigated by several authors but the exact mechanisms have not yet been established. To study whether kinin-releasing systems are involved in these adverse reactions, we determined total plasma kininogen levels at intervals up to 30 minutes after the intravenous injections of contrast media in dogs. Injections of iohexol, iopamidol, and iothalamate decreased total plasma kininogen levels. This effect increased with increasing dose of the media and suggests that they activated the kinin-releasing systems in the plasma.

Animals↗
PubMed1988

Effects of intravenous contrast media on cortical and medullary blood flow in the rat kidney.

The effect of slow intravenous infusion of contrast medium (CM) (1600 mg I/kg body weight) on cortical blood flow (BF) and medullary BF in rat kidneys was investigated by laser-Doppler flowmetry on either renal cortex or exposed renal papillas (inner medulla). The effect on cortical BF was evaluated after infusion of either ioxaglate, iohexol, or ioxithalamate. Mannitol and Ringer's solution were used as control substances. The effect on medullary BF was examined after infusion of either ioxaglate, iohexol, iopamidol, ioxithalamate, or mannitol. BF was measured continuously during a 30-minute control period and a 60-minute experimental period, starting with the CM infusion. Cortical BF was unchanged in the ioxaglate group and significantly increased in the iohexol, ioxithalamate, and mannitol groups (P less than .05). Medullary BF was moderately increased in the ioxaglate group (P less than .05) but moderately decreased in the groups that received iohexol, iopamidol, ioxithalamate, or mannitol (P less than .05). The reduction in medullary BF following infusion of the ratio 3.0 nonionic CM and of the ratio 1.5 ionic CM might be one contributory mechanism to the pathogenesis of CM nephropathy, especially in the presence of microangiopathy in the kidney.

Animals↗
PubMed1989

Effect of iodinated contrast media on blood clotting.

Recently, blood clot formation in catheters used for the injection of nonionic contrast media (CM) during angiography has been reported as being due to activation of hemostasis in the catheter. However, CM exhibit inhibitory properties regarding coagulation and platelet functions. The effect on blood clotting of iohexol, iopamidol, ioxaglate, diatrizoate, and ioxitalamate at a ratio of 10% v/v with nonanticoagulated human whole blood was evaluated using the kinetics of fibrinopeptide A (FpA) generation. Blood aliquots were taken every 2 minutes until blood clot occurred. Two groups of contrast media were identified: (1) iohexol and iopamidol, which increased the clotting time, and (2) ioxaglate, diatrizoate, and ioxitalamate, for which all clotting times were over 30 minutes and no FpA generation occurred.

Blood Coagulation↗
PubMed1990

Experimental tissue damage after subcutaneous injection of water soluble contrast media.

Various water soluble contrast media (WSCM) were injected subcutaneously into 970 hind feet of 485 rats. Gross morphologic changes were seen after the injection and analyzed as a function of various physicochemical characteristics of WSCM. The WSCM of larger volume, higher osmolality, higher iodine content, and meglumine salts rather than sodium salts caused more severe tissue damage; younger rats showed more severe tissue damage by WSCM of high osmolality.

Animals↗
PubMed1990

Inhibition of angiotensin-converting enzyme by contrast media. I. In vitro findings.

There is increasing evidence that activation of the plasma contact system that results in the production of bradykinin plays an important role in contrast material systemic reactions. The effects of bradykinin in anaphylaxis depend on its rate of destruction and its rate of production. The highest percentage of contrast material reactions occur after intravenous injections, and the major enzyme hydrolyzing bradykinin (kininase II; angiotensin-converting enzyme) is found on pulmonary vascular endothelial surfaces. The inhibitory effects of numerous ionic and nonionic contrast material solutions on the enzyme have been determined. Additionally, the role in this inhibition of the chelators found in all commercial contrast material vials has been studied. In vitro, all such preparations combined with their chelators inhibit angiotensin-converting enzyme. Whether this inhibition plays a role in vivo remains to be established.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

Assays for plasma complement activation by x-ray contrast media.

Hemolytic complement activity and a C3a radioimmunoassay (RIA) were investigated for their ability to characterize contrast media (CM) with respect to complement activation. The CM tested were commercial formulations of diatrizoate, iodamide, iothalamate, ioxaglate, iohexol, and iopamidol. When plasma was exposed to CM, the hemolytic complement activity decreased and the C3a concentration increased. The C3a assay had a larger dynamic range and therefore more ability to discriminate among the CM. Using C3a data from pooled plasma or from individual donors' plasma, nonionic iopamidol (as Isovue 300) had lower complement-activating potential (P less than .005 and P greater than .05, respectively) than all of the ionic media based on diatrizoate, iothalamate, iodamide, and ioxaglate. The ranges of mean C3a values generated by saline, nonionic CM, and ionic CM were 48 to 60, 65 to 173, and 807 to 3272 ng C3a/50 microL, respectively. Complement activation was found to correlate with osmolality (r = 0.945, all media) and with molarity (r = 0.994, diatrizoates).

Complement Activation↗
PubMed1991

Experimental nephrotoxicity of the radiocontrast agents iohexol, ioxaglate, and iothalamate. An in vitro and in vivo study.

The authors compared the renal toxicity of the low osmolality radiocontrast agents, iohexol and ioxaglate, and the ionic agent, iothalamate, at equivalent iodine dose, using experimental models in vitro and in vivo. In isolated perfused rat kidneys, all agents induced comparable biphasic hemodynamic changes, associated with similar declines in glomerular filtration rate (GFR) and tubular necrosis. In two different in vivo models (using multiple insults combined with the administration of radiocontrast), iothalamate appeared to induce more severe morphologic injury. Despite similar nephrotoxic potential in vitro, the newer radiocontrast agents, iohexol and ioxaglate, cause in vivo less renal injury than iothalamate in the experimental models.

Angiotensin II↗
PubMed1992

Changes in serum magnesium during excretory urography. A comparison of ionic and nonionic contrast media.

RATIONALE AND OBJECTIVES: It is known that ionic contrast media (CM) bind magnesium and that patients with asthma often benefit from magnesium injections. Similarly, asthmatics have a higher incidence of CM reactions. This work tests the hypothesis that ionic CM alter serum magnesium more than nonionic CM. METHODS: Ten patients were divided into two groups; one group received iothalamate and the other received iohexol. RESULTS AND CONCLUSIONS: The total magnesium level changed significantly from baseline in the iothalamate-treated group (P less than .01). Iothalamate produced a significant decrease in protein-bound magnesium (P less than .01) with a significant increase in filterable magnesium (P less than .01). Iohexol did not produce significant changes for any of the magnesium fractions. The patient with the most clinically significant adverse reaction (though minor) had the lowest baseline magnesium level. Further studies with larger groups including patients with asthma are needed.

Azo Compounds↗
PubMed1993

Effects of ioversol versus iothalamate on endothelin release and radiocontrast nephropathy.

RATIONALE AND OBJECTIVES: Certain radiocontrast agents, including iothalamate, iohexol, and ioxaglate, release the renal vasoconstrictor peptide endothelin from vascular endothelium in a way that might contribute to radiocontrast nephropathy. The effects of the nonionic, low osmolar agent, ioversol, on endothelin release and renal function are investigated. METHODS: Effects of ioversol were compared with equi-iodine doses of iothalamate when applied to cultured bovine aortic endothelial cells or injected into normal rats and rats preconditioned by uninephrectomy, salt depletion, and indomethacin (USIC) to develop radiocontrast nephropathy. RESULTS: In comparison with iothalamate, ioversol had a greatly reduced propensity to stimulate the release of endothelin, from cultured cells and when injected into anesthetized rats. Ioversol produced less renal vasoconstriction than did iothalamate, in control and in USIC rats, and the development of radiocontrast nephropathy, assessed by creatinine clearance and morphologic damage to the renal medulla, was largely avoided. CONCLUSIONS: These results strengthen the hypothesis that endothelin release induced by radiocontrast agents is correlated with their renal toxicity and therefore, may play a role in radiocontrast nephropathy.

Animals↗
PubMed1993

Methods for mitigating soft-tissue injury after subcutaneous injection of water soluble contrast media.

RATIONALE AND OBJECTIVES: Water soluble contrast media may cause tissue injury by extravasation during intravenous injection during various radiologic examinations. The authors attempted to find out what kind of management could mitigate tissue injury when extravasation of water soluble contrast media occurs. METHODS: Sodium and meglumine ioxithalamate was injected subcutaneously into 240 hind feet of 120 rats that were divided into six groups according to the methods of experimental management. Experimental managements included the following: no further management (control), injection of distilled water, injection of normal saline, injection of hydrocortisone, hot water application, and cold water application. Gross morphologic changes in each group were compared with those in the control group. RESULTS: Only the saline injection group showed statistically significant decrease of tissue injury compared with the control group. CONCLUSIONS: Saline injection lessens the degree of soft-tissue injury at contrast media extravasation sites in rats.

Animals↗
PubMed1979

Evidence of CSF enhancement in the spinal subarachnoid space after intravenous contrast medium administration: is intravenous computer assisted myelography possible?

Following intravenous injection of iodinated contrast medium, peripheral enhancement of the area inside the spinal canal, is frequently observed by computed tomography. This may be due, at least in part, to enhancement of the cerebrospinal fluid in the spinal subarachnoid space. Our preliminary observations in human patients and in animal experiments are reported. The goal of intravenous computer assisted myelography is worth pursuing.

Cerebrospinal Fluid↗