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PubMed1978

Comparative evaluation of metrizamide and meglumine ioxithalamate in angiography of the vessels of the head and neck.

Metrizamide, a non-ionic contrast medium of low osmolality was compared with meglumine ioxithalamate, the ionic angiographic contrast medium currently in use in our department in a double-blind study. Criteria upon which the comparison was based were: 1) the pain reaction of the patient upon intra-arterial contrast injection, 2) bradycardial reactions upon common carotid injection and 3) the quality of the contrast image. Metrizamide induced significantly less painful sensations than meglumine ioxithalamate in those vessels in which injections of contrast medium are frequently painful (external carotid artery, vertebral artery). No significant difference in the degree of bradycardia was caused by the two contrast media. The degree of bradycardia was also found to be poorly reproducible upon successive injections of the same contrast medium in the same patient, thus raising questions as to the suitability of this method for determining the toxicity of the contrast medium. The quality of the angiograms obtained did not differ significantly with the two media. Spasm, when it occurred during selective external carotid injections, was found to be independent of the contrast agent used, being correlated instead with the depth of distal advance of the catheter tip into the external carotid. Of the 51 patients included in the study, two patients suffered transient neurological deficit after angiography with metrizamide, and one patient suffered a permanent hemiplegia after angiography with meglumine ioxithalamate.

Aorta, Thoracic↗
PubMed1979

Adverse side effects of metrizamide in myelography.

The adverse side effects in a series of 439 myelographies with metrizamide were analyzed. The most frequent side effect was headache, which could be differentiated as early onset headache, related to hydrodynamic modifications in the spinal fluid following lumbar puncture, and late onset headache related to a metrizamide effect. The frequency of late onset headache was at least 27%, but all together 46% of the patients had postmyelographic headache. Meningeal irritation was seen in 5%, sometimes in a severe form, mimicking a septic complication. Spinal irritation and epileptic fits were rarely seen. Striking was the occurrence of an acute psycho-organic syndrome, frequently observed after cervical myelography which was performed with a higher than usual dose of iodine. We can not confirm the general opinion that the central nervous system had a good tolerance for metrizamide.

Anaphylaxis↗
PubMed1977

Cerebral angiography with non-ionic (metrizamide) and ionic (meglumine metrizoate) watersoluble contrast media. A comparative study with double blind technic.

The adverse effects of cerebral angiography with metrizamide and meglumine metrizoate were compared in 20 patients for each contrast medium using a double blind technic. Deterioration of the EEG and bradycardial reactions were seen more often with meglumine metrizoate than with metrizamide and these differences were statistically significant. Metrizamide also had a shorter circulation time, less influence on the blood pressure and EMG than meglumine metrizoate, but these differences were not statistically significant. The clinical examinations showed no difference in the minor adverse effects. One patient had transient hemiparesis and dysarthria after angiography with meglumine metrizoate but no serious complications were seen in the others.

Adolescent↗
PubMed1981

Properties of ribosomes centrifuged in metrizamide gradients.

The banding of ribonucleoproteins in metrizamide has been characterised using yeast ribosomes as a model system. Metrizamide does not dissociate ribosomes but it can facilitate the loss of loosely bound proteins. The buoyant density of fixed ribosomes in metrizamide gradients increases dramatically in the presence of low concentrations of Mg2+, whilst high Mg2+ concentrations give rise to multiple bands of higher density. These phenomena can be explained in terms of the binding of Mg2+ to high and low affinity sites as proposed for Escherichia coli ribosomes.

Cell Fractionation↗
PubMed1988

[EEG study after cervical myelography with iopamidol and metrizamide].

In an open investigation on 100 patients, changes in the electroencephalogram following ascending cervical myelography with iopamidol 250 or metrizamide were studied. In the postmyelographic EEG, there were normal findings in 36 patients after iopamidol and 26 after metrizamide. A comparison of the pathological results after iopamidol and metrizamide yielded a relation of 6:2 for mild, 2:5 for moderate, and 0:6 for severe degree of slowing, 4:6 for basal theta wave activation, and 2:5 for increased cerebral excitability. The results were statistically significant on the 5% level according to the chi-square test.

Brain↗
PubMed1974

Isopycnic sedimentation of DNA in metrizamide: the effect of low concentrations of ions on buoyant density and hydration.

Metrizamide, an inert, non-ionic organic compound, dissolves in water to give a dense solution in which DNA bands isopycnically at a density corresponding to that of fully hydrated DNA. Density-gradient centrifugation in solutions of metrizamide has been used to determine the effects of very dilute solutions of salts on the buoyant density of native and denatured DNA. It has been shown that the buoyant density of DNA is dependent on both the counter-cation and the anion present. Interpretation of the data in terms of the degree of hydration of the macromolecule indicates that (i), NaDNA is more highly hydrated than CsDNA; and (ii), the hydration of NaDNA varies with anion in the order sulphate< fluoride< chloride< bromide< iodide. It is suggested that isopycnic centrifugation in metrizamide is a simple method for determining the effects of salts (and other small molecules) on the hydration of nucleic acids under conditions of high ratios of salt to DNA (> 5 x 10(3) moles/mole) while high (0.999) water activity is maintained.

Animals↗
PubMed1977

Metrizamide dissociates nuclear particles containing heterogeneous nuclear RNA.

Metrizamide gradients were tested for the possible fractionation of the constitutive units of nuclear particles. Material from 35-55 S monoparticles was indeed distributed along the gradient but rerun experiments, CsCl density determinations, formaldehyde fixation prior to centrifugation suggested that the separation was due to dissociation or (and) action of endogeneous ribonucleases rather than to monoparticle fractionation. That dissociation had indeed occured was confirmed by the study of 60-110 S polyparticles. They were dissociated into ribonucleoproteins rich in phosphoproteins and into free proteins. These products were essentially similar to those obtained after NaCl treatment of the particles though the modes of action of metrizamide and NaCl are likely to be different. The loss of proteins from particles reaches 60-70% and we conclude that metrizamide gradients are not utilizable for the fractionation of the units of nuclear particles.

Animals↗
PubMedDate not supplied

A comparison of the hemodynamic responses to metrizamide and meglumine/sodium diatrizoate in canine renal angiography.

Selective renal angiography causes a biphasic change in renal blood flow and vascular resistance. In this study, 5 ml of meglumine/sodium diatrizoate (288 mg I/ml, 1455 mosm/kg), metrizamide (290 mg I/ml, 593 mosm/kg), isontonic saline (287 mosm/kg) and hypertonic saline (1500 mosm/kg) were injected into the renal arteries of seven adult mongrel dogs to determine whether the minimum flow (or maximum resistance) was related to the osmolality of the injected agent. The maximum resistance response was significantly smaller for metrizamide (20 +/- 4%) and isotonic saline (19 +/- 2%) than for diatrizoate (36 +/- 6%) or hypertonic saline (50 +/- 7%). Hypertonic saline produced two distinct types of responses: the typical biphasic response or a severe immediate drop in flow. Thus the maximum resistance response was related to agent osmolality. The "injection artifact," or flow changes occurring during the injection, were different for the four agents, and these differences appeared correlated to agent viscosity. Although both contrast media caused relatively small changes in renal hemodynamics, metrizamide caused significantly smaller changes than meglumine/sodium diatrizoate.

Animals↗
PubMedDate not supplied

Metrizamide, the ideal radiopaque filling material for detachable silicone balloon embolization.

Porcine visceral and extremity arteries were embolized with detachable silastic balloons; 10 balloons were filled with isoosmolar metrizamide, five were filled with 30% meglumine-sodium diatrizoate and five were filled with 3:1 mixtures of blood and 76% meglumine-sodium diatrizoate. Follow-up radiographs were obtained weekly for 2 weeks, at 4 weeks and at 5 months. At 3 months, arteriography was performed. All balloons occluded the vessel completely upon detachment. Balloons filled with metrizamide did not change their volume or radiopacity during the entire observation period and all remained inflated. The balloons filled with diatrizoate salts enlarged by osmotic growth during the first two weeks and there was a decrease in opacity. Thereafter, one balloon filled with 30% diatrizoate salt solution and one filled with blood-76% diatrizoate deflated. In the former, the embolized artery remained occluded, while in the latter, the vessel reopened and the balloon was found incorporated into the vessel wall at the site of detachment. It is concluded that isoosmolar metrizamide is an ideal filler for detachable silastic balloons since it does not lead to changes in volume or radiopacity and also guarantees long-term vascular occlusion.

Angiography↗
PubMedDate not supplied

Metrizamide optic nerve sheath opacification.

The safety of metrizamide in the optic nerve sheath has not been studied to our knowledge. We studied histologic changes produced by metrizamide in the optic nerve of cats with surgically created lesions simulating orbital tumors and trauma. Displacement, compression, and disruption of the optic nerve sheath were detectable by radiographing the opacified sheath. Arachnoiditis of the optic nerve sheath is unlikely from a single exposure to metrizamide in a concentration less than 300mg I/ml.

Animals↗
PubMedDate not supplied

Effect of oral metrizamide on hematocrit and serum osmolality in the neonate.

Sixteen newborns and young infants, weighing between 800 and 5200 grams, received orally administered metrizamide for evaluation of suspected gastrointestinal pathology. Images were judged good to excellent in 14 cases. No effect of metrizamide on hematocrit and serum osmolality was noted. Metrizamide appears to be a relatively safe and effective agent for examination of the neonatal gastrointestinal tract.

Administration, Oral↗
PubMedDate not supplied

Intrathecal toxicity of iohexol vs. metrizamide. Survey and current state.

Arachnoiditis, a common finding in patients who have had previous myelograms or spinal surgery, can cause pain, paresis, and can slow elimination of contrast medium from the subarachnoid space. The role of contrast media in producing arachnoiditis has not been well defined but can be studied in a primate model. This study compared incidence of arachnoiditis in monkeys after myelograms using two nonionic contrast media, iohexol and metrizamide. Conditions were chosen to produce the greatest possible effect of contrast medium on the arachnoid. Animals were sacrificed 12 weeks after the myelogram and the dural sac was removed for examination by light microscope. Under adverse conditions, high doses and high concentrations of iohexol produced little arachnoiditis, while metrizamide produced mild to moderate arachnoiditis. Iohexol was shown to have a greater margin of safety then metrizamide, which is considered an important clinical advantage.

Animals↗
PubMed1978

Metrizamide demonstration of the subarachnoid space surrounding the optic nerves.

Intrathecal instillation of metrizamide has provided a useful tool for the in vivo evaluation of smaller structures adjacent to or within the subarachnoid cisterns. The authors report a case in which metrizamide filled the thin subarachnoid space surrounding the optic nerve in its course through the orbit. The finding appears to be infrequent, however, since it was not observed in any instance in a review of 80 metrizamide computed tomographic cisternograms in patients with normal intracranial pressure.

Adult↗
PubMed1980

Explanation of metrizamide brain penetration: a review.

The penetration of intrathecally injected metrizamide into brain and spinal cord substance is a phenomenon that has surprised and puzzled radiologists. No suitable explanation has been offered in the radiologic literature. This article reviews the recent literature on the relationship between the cerebrospinal fluid (CSF) space and the extracellular fluid (ECF) space of the brain. Recent evidence has shown that these spaces are in fact one compartment with no diffusion barrier between them. Thus, penetration of metrizamide into the brain is an expected rather than surprising phenomenon. An explanation is offered as to why metrizamide does not penetrate edematous or infarcted portions of brain on the basis of a pressure gradient between damaged brain ECF and CSF spaces.

Brain↗
PubMed1984

Computed tomography with metrizamide myelography to define the extent of spinal canal block due to tumor.

In five patients with complete spinal block due to tumor, CT was used to show the upper level of the block. In each case metrizamide myelography demonstrated the lower level of the block, but not enough metrizamide leaked past the block to allow myelographic identification of the upper level. However, the subarachnoid space both below and above the level of the block was clearly outlined by metrizamide on CT in each case.

Adolescent↗
PubMedDate not supplied

Low-dose metrizamide spinal computed tomography in outpatients.

Delineation of the thecal sac in CT can be improved by the presence of intrathecal metrizamide. This may be especially helpful in postoperative patients in whom the landmarks are often obscured by epidural scarring. Metrizamide-enhanced CT was performed on outpatients using 2 1/2 ml metrizamide (170 mg I/ml). Follow-up is available on 40 patients. The procedure was well tolerated with only three instances of severe headache, one case of vomiting, and no reported seizures. Adequate opacification was obtained at 92% of the levels examined with fair opacification at the remainder of the levels. This technique is considered a safe and useful outpatient procedure.

Adult↗
PubMed1977

Separation of isolated cell nuclei of tissues of the meal moth, Ephestia kuehniella Z. by metrizamide density gradient centrifugation.

The behaviour of isolated cell nuclei of different tissues in the mediterranean meal moth has been studied in metrizamide density gradients to find whether differences exist in the bouyant density between nuclei derived from different specialized tissues. The different nuclei studied have buoyant densities ranging form 1.228-1.295 g/cm3 in metrizamide density gradients and clear differences exist between different populations of nuclei. The different buoyant densities make it possible to separate isolated nuclei from a heterogeneous population of nuclei according to their characteristic densities. This has been tested by the separation of silk gland nuclei from follicle cell nuclei by the density centrifugation method. The degree of polyploidy of the nuclei is not correlated to a decrease or increase of the buoyant density, which suggests that different amounts of nuclear proteins, ribonucleoproteins or RNA are responsible for the differences determined. These tissue-specific differences of the nuclear densities might be correlated to different transcriptional activities. In addition to this, the isopycnic sedimentation technique in metrizamide density gradient provides a method to purify nuclei very carefully without any visible alteration of their morphology and integrity.

Animals↗
PubMed1985

Metabolic effect of topical application of metrizamide to rat brain cortex.

The x-ray contrast material metrizamide is structurally related to 2-deoxyglucose and inhibits brain glucose phosphorylation both in vitro and in vivo. in vivo. In vivo, however, the present autoradiographic study with labeled 2-deoxyglucose revealed a local increase of glucose metabolic rate in an area of direct metrizamide application to the cerebral cortex. The local increase was 137% above the metabolic rate calculated for the contralateral region. Regions outside the application site showed no difference between the glucose metabolic rates of the ipsi- and contralateral hemispheres. Evidence from the literature suggests that metrizamide may stimulate cortical activity by inhibiting acetylcholinesterase.

Administration, Topical↗