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Tolerance of iohexol, iopamidol, and metrizamide in lumbar myelography.

Iohexol and iopamidol, two new nonionic contrast media, have been extensively studied in comparison with metrizamide for lumbar myelography. Review of the literature with statistical analysis indicates both agents are superior to metrizamide in terms of number of patients with adverse reactions (p less than 0.001). Preliminary data suggest, but do not prove, that use of iohexol may result in fewer side effects than iopamidol.

Humans↗

Epidermoid tumor of the fourth ventricle: use of metrizamide-computed tomography.

This report describes two cases of epidermoid tumor of the fourth ventricle diagnosed with metrizamide computed tomography. They both presented as a low-density lesion in the region of the fourth ventricle on computed tomography. They did not show any enhancement after intravenous injection of contrast medium and had no hydrocephalus. Metrizamide-enhanced computed tomography demonstrated the irregular fourth-ventricular filling defect characteristic of epidermoid tumors.

Adult↗

Purification of infectious rubella virus by gel filtration on sepharose 2B compared to gradient centrifugation in sucrose, sodium metrizoate and metrizamide.

Rubella virus was purified by chromatography on Sepharose 2B after concentration by ultrafiltration on hollow fibers and hydroextraction with PEG 20,000. Yields of 40% infectivity and 70% hemagglutinating activity were routinely obtained. Chromatographic purification was compared to ultracentrifugation in sucrose, metrizamide and sodium metrizoate. Yields were lower in sucrose and metrizamide, while sodium metrizoate reduced the infectivity of the virus below detectable levels. These results demonstrate the advantage of Sepharose 2B for the purification of infectious rubella virus.

Centrifugation, Density Gradient↗

Isolation of rat somatotroph and mammotroph secretory granules by equilibrium density centrifugation in a linear metrizamide gradient.

A procedure has been developed for separating rat somatotroph and mammotroph secretory granules from other membranous organelles. The approach devised is a 6-step procedure involving filtration and equilibrium and rate density-gradient centrifugation in Metrizamide gradients of low ionic strength. The use of Metrizamide minimizes disruption and solubilization of the contents of these granules. The majority of the somatotroph and mammotroph granules can be isolated in a gradient fraction virtually free of any mitochondria, microsomes or other secretory granules.

Animals↗

Isopycnic banding in metrizamide of the uterine cytosol and nuclear estradiol receptor.

We have characterized the cytosol and the nuclear estrogen receptors (RE) of immature lamb uterus and their complexes formed with DNA and chromatin by using metrizamide isopycnic gradients. In low salt, the cytosol RE had a density of 1.238 +/- 0.002 g/cm3. This density was increased by Ca2+-activated proteolysis (1.275 g/cm3) and heat transformation of the receptor (1.257 g/cm3) and lowered by trypsin treatment (1.20 g/cm3), DNA binding (1.20 g/cm3) or molybdate treatment. In high salt (0.5 M KCl) both the native and the heat-"transformed" cytosol RE banded at the same density of 1.26 g/cm3. The 8S RE had the same density when bound to E2 or to 4-hydroxy-tamoxifen. Endometrial nuclei purified after nuclear translocation of RE were digested by micrococcal nuclease to solubilize the nuclear RE under low salt conditions. The majority of the extracted nuclear RE had a density similar to that of the 8S cytosol RE (1.239 +/- 0.002) and thus was different from the proteolyzed and heat "transformed" forms. Conversely, after a slight digestion of the nuclei, RE banded with chromatin at 1.208 +/- 0.001 g/cm3. In low salt, both forms of the nuclear RE, but not the trypsin proteolyzed nuclear RE, were displaced by naked DNA added in vitro. We conclude that the cytosol RE and the free nuclear RE have, in low salt, the same density and DNA-binding ability and that metrizamide isopycnic analysis is a good method for quantifying the interactions of the receptor with DNA and chromatin.

Animals↗

Ependymoma of filum terminale: metrizamide-enhanced CT evaluation.

Two cases of surgically proven myxopapillary ependymomas of filum terminale are reported. In both, myelography and metrizamide-enhanced computed tomographic (CT) scans were performed. An intramedullary tumor in the lower thoracic spine, soft-tissue masses in the neural foramina and enlarged bony spinal canal in the lower thoracic and upper lumbar spine were noted in one case and, in the other, an intradural extramedullary tumor at T12-L1 level. Both patients had normal cranial CT scans, and both presented with similar symptoms--low back pain and weakness and paresthesia of leg or legs for up to 3 years' duration. Myelography and metrizamide-enhanced CT scans were performed in order to evaluate disc disease in one patient and spinal stenosis in the other. Ependymoma was an incidental finding, which was then removed by surgical resection. Pathology confirmed the diagnosis.

Adult↗

Epidurography using metrizamide an out-patient examination.

An improved technique of epidurography using metrizamide is described. Fifty patients were examined in order to establish whether the technique can be satisfactorily performed as an outpatient procedure and whether it is as useful as radiculography. The findings indicate that metrizamide epidurography is a safe examination, providing at least as much information as radiculography. Our patients tolerated the examination well, avoiding the after effects associated with intradural techniques, and were able to leave hospital a few hours later. No untoward sequelae occurred.

Ambulatory Care↗

Visual evoked response changes following intrathecal injection of water-soluble contrast media: a possible method of assessing neurotoxicity and a comparison of metrizamide and iopamidol.

An investigation was carried out to ascertain if there was a change in visual evoked responses following the intrathecal injection of water-soluble contrast media for myeloradiculography and if this change provided an indication of neurotoxicity as assessed by the onset of headache during a period of 20 h following the radiological examination. The patients were unselected and examined, when facilities for measuring the visual evoked response were available, immediately before and at 1 and 20 h after the examination. Control readings were carried out before, 1 h and 20 h after lumbar puncture in patients who did not have an injection of contrast medium. The first 25 patients in the series received metrizamide; when iopamidol became available a change to the newer medium was made and iopamidol was used on all subsequent patients. All the injections were carried out by the same radiologist and the patients were kept in hospital overnight and interviewed the next morning, avoiding a specific reference to headache unless the patient denied all symptoms. It was found that the latency of the visual evoked response was affected in some cases by the presence of contrast medium in the cerebrospinal fluid and that there was a correlation between the severity of headaches and the delay in the visual evoked response at the 20 h post-myelogram measurement, but not at 1 h after the examination. It would appear, therefore, that the visual evoked response measurement is a valid method of assessing, in the short term, the neurotoxicity of intrathecal water-soluble contrast media and that, on this evidence, iopamidol is less neurotoxic than metrizamide. We are not aware of any long-term complications resulting from the use of either contrast medium.

Contrast Media↗

Accessory cells with a morphology and marker pattern of dendritic cells can be obtained from elutriator-purified blood monocyte fractions. An enhancing effect of metrizamide in this differentiation.

Human monocytic cell fractions obtained by counterflow elutriation centrifugation (with regard to specific monocyte/macrophage characteristics: 82-88% were positive for nonspecific esterase; 86-94% for CD14) were cultured (overnight, 37 degrees C) under nonadhering conditions (polypropylene tubes). Thirty to 40% of the cells were found to differentiate into large, monocytoid cells with a dendritic morphology. These cells expressed a marker of active dendritic cells RFD1 in 76-89% and were also positive for class II MHC antigens as identified by OKIa (95-97%). An exposure of the blood monocytic cells to metrizamide (30 min, 14.5%) prior to the overnight culture enhanced this differentiation, and 47-58% of cells with a dendritic morphology were found (of which 80-87% RFD1 positive, and 95-97% Class II MHC positive). The cultured cell populations containing the cells with the morphology and marker pattern typifying dendritic cells, appeared functionally more active as accessory populations when compared to freshly isolated blood monocytic cell fractions; the cultured cells had an enhanced stimulator capability in MLR, and cluster formation with lymphocytes was more prominent. At the same time, the cultured cell population showed a decreased bactericidal activity when compared to the freshly isolated monocytic populations, and in addition, all the cultured monocytoid cells had lost non-specific-esterase activity, while only approximately 10% of cells were still positive for the CD14 marker. When U937 cells were exposed to metrizamide (14.5% concentration, 30 min) and cultured under nonadhering conditions for 36 hours, similar changes were observed (30-45% became dendritic, 20% RFD1 positive).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Presenting Cells↗

Localisation of a CSF fistula by metrizamide CT cisternography.

Localisation of a cerebrospinal fluid fistula in the nasal region is difficult. Lack of a suitable roentgen contrast medium for intrathecal use has earlier restricted the utility of cisternography. Metrizamide cisternography and CT have recently proved to be well tolerated and effective in revealing CSF fistulae. A case report of operatively treated CSF rhinorrhea recurring after three years is presented. With the help of CT metrizamide cisternography, the fistula could finally be localised in the sphenoidal sinus. The re-operation confirmed this finding. The technique of cisternography is described.

Aged↗

Separation of erythrocytes infected with murine malaria parasites in metrizamide gradients.

Density gradients with metrizamide, a tri-iodinated benzamido derivative of glucose, have been used to separate erythrocytes infected with 3 species of murine plasmodia. Good separations were obtained of uninfected erythrocytes from erythrocytes containing parasites in different developmental stages. With metrizamide solutions, the densities required for isopyenic separation can be obtained without hypertonicity or high viscosity, and the viability and those aspects of the metabolism of parasites and erythrocytes that we measured are not detectably modified by exposure to these solutions. This type of separation has many possible applications to biochemical and immunological investigations.

Animals↗

Isolation of rat liver lysosomes by isopycnic centrifugation in a metrizamide gradient.

A preparation, similar to the light mitochondrial fraction of rat liver (L fraction of de Duve et al, (1955, Biochem. J. 60: 604-617), was subfractionated by isopycnic centrifugation in a metrizamide gradient and the distribution of several marker enzymes was established. The granules were layered at the top or bottom of the gradient. In both cases, as ascertained by the enzyme distributions, the lysosomes are well separated from the peroxisomes. A good separation from mitochondria is obtained only when the L fraction if set down underneath the gradient. Taking into account the analytical centrifugation results, a procedure was devised to purify lysosomes from several grams of liver by centrifugation of an L fraction in a discontinuous metrizamide gradient. By this method, a fraction containing 10--12% of the whole liver lysosomes can be prepared. As inferred from the relative specific activity of marker enzymes, it can be estimated that lysosomes are purified between 66 and 80 times in this fraction. As ascertained by plasma membrane marker enzyme activity, the main contaminant could be the plasma membrane components. However, cytochemical tests for 5'AMPase and for acid phosphatase suggest that a large part of the plasma membrane marker enzyme activity present in the purified lysosome preparation could be associated with the lysosomal membrane. The procedure for the isolation of rat liver lysosomes described in this paper is compared with the already existing methods.

Acid Phosphatase↗

Complex of DNA with chromatin proteins investigated by isopycnic centrifugation in metrizamide.

Complexes of mouse main band DNA with a fraction of non-histone proteins (NHP), having a high affinity for DNA, in the absence or presence of histones have been investigated by gradient centrifugation in metrizamide. Two types of complexes were formed at an input ratio of NHP to DNA between 1 and 2.5. In metrizamide gradients a majority of DNA was found in the light complex (at the density of 1.14-1.16 g/cm3) even at the very high NHP to DNA ratio. When histones were present in the reaction mixture, most of the DNA was found in the heavy complex (1.19-1.21 g/cm3). The electrophoretic profiles of the proteins recovered from the heavy and light complexes were different; some fractions of nonhistone proteins were present only in the heavy component.

Animals↗

Intrathecal tolerance of metrizamide in chloralose anesthetized cats.

The water soluble radiopaque medium, metrizamide (Amipaque) was introduced into the lumbar subarachnoid space in chloralose anesthetized cats at a standard volume of 0.35 cc/kg in concentrations of 300 mgI/cc to 500 mgI/cc during EMG recording. These animals did not differ from controls which received cerebrospinal fluid under otherwise identical conditions; both groups usually showed some mild and occasional muscle fasciculations or mild spasms. Treatment with metrizamide appeared to be a less deleterious procedure than that using hyperosmotic sucrose (1.32 M) as judged from EMG records. In contrast, equivalent amounts of neglumine iothalamate produced frank convulsions in 7 of 15 cases and a range of hyperirritability in the remaining 8.

Anesthesia↗

Cardiac function during coronary arteriography with calcium enriched diatrizoate and metrizamide.

Calcium was added to diatrizoate (Renografin 76) and metrizamide (Amipaque) to concentrations from 2.5 to 50 mEq/1. The solutions were injected into the left coronary artery in dogs with either the chest opened or closed. In open chest experiments contractile force and aortic pressures were recorded. In closed chest dogs, left ventricular pressure, first derivative of that pressure and aortic pressure were registered. The calcium ion concentration was linearly, inversely related to the effect of the contrast solutions on the recorded parameters. In these experiments the optimal amount of calcium is suggested to 40 mEq/1 added to the diatrizoate solution but only 10 mEq/1 added to the metrizamide solution. No ECG changes due to calcium addition could be registered. The cardiac toxicity of these contrast media seem to be due to an interference with the calcium flux across the cell membrane. The effect on contractility can be recorded with the same reliability in either closed or open chest experiments.

Angiocardiography↗

Arachnoiditis from myelography with iopamidol, metrizamide, and iocarmate compared in the animal model.

A new aqueous myelographic contrast media, iopamidol, was compared to iocarmate and metrizamide with respect to the risk of arachnoiditis. Macaque monkeys underwent myelography with one of the three contrast media. Twelve weeks later, the animals were restudied with myelography, then sacrificed for histologic studies of the arachnoid. Results suggest that iopamidol is safer than iocarmate and equivalent to metrizamide with respect to the risk of arachnoiditis.

Animals↗

Quantitative multiregional CSF kinetics using serial, metrizamide enhanced computed tomography.

Two rhesus monkeys studied by serial metrizamide (Amipaque) enhanced computer tomography (CT) imaging were used to quantitatively analyze cerebrospinal fluid (CSF) kinetics in multiple anatomical regions. Time--density curves were generated for the cisterna magna, suprasellar cistern, quadrigeminal cistern, and sylvian fissure, If clinical, biochemical, and routine static CT scanning indicate a profile suggesting normal pressure hydrocephalus, then CSF kinetics may be quantitatively and dynamically studied by CT imaging with metrizamide enhancement. This multiregional approach may be applied in an attempt to accurately distinguish normal pressure hydrocephalus from cerebral atrophy as a means of predicting which patients will likely profit from surgical diversionary shunting.

Animals↗