Sodium Iothalamate Research Articles

Role of endothelin and prostaglandins in radiocontrast-induced renal artery constriction

Infusion of radiocontrast agents in vivo results in renal artery constriction and subsequent renal hypoperfusion. To examine the role of endothelin and of prostaglandins in radiocontrast-mediated renal vasoconstriction, rats were treated with an endothelin receptor antagonist, CP170687, and with indomethacin. The dose of CP170687 utilized was sufficient to reverse endothelin1-mediated constriction of isolated aortic rings and of renal blood flow in intact rats. In normal rats there was a transient drop in renal blood flow to 80% of baseline following sodium iothalamate injection, an effect which was not prevented by CP170687. In rats first given indomethacin, the drop in renal blood flow was more pronounced (to 63% of baseline) and was sustained. In this instance, CP170687 fully reversed the sustained decrease of renal perfusion. CP170687 also diminished the rise in systemic blood pressure seen following iothalamate injection. In the absence of indomethacin, iothalamate increased urinary prostaglandin E2 to a maximum of sevenfold above baseline values. In summary, injection of radiocontrast results in an immediate decrease in renal blood flow that is counteracted by an increase in renal prostaglandin formation. When prostaglandin synthesis is inhibited, prolonged endothelin-mediated renal vasoconstriction is observed that is reversed by an endothelin receptor antagonist.

Obesity-induced hypertension. Renal function and systemic hemodynamics.

This study examined the control of renal hemodynamics and tubular function, as well as systemic hemodynamics, during obesity-induced hypertension in chronically instrumented conscious dogs. Mean arterial pressure, cardiac output, and heart rate were monitored 24 hours a day using computerized methods, water and electrolyte balances were measured daily, and renal hemodynamics were measured each week during the control period and 5 weeks of a high-fat diet. After 7 to 10 days of control measurements, 0.5 to 0.9 kg of cooked beef fat was added to the regular diet, and sodium intake was maintained constant at 76 mmol/d throughout the study. After 5 weeks of the high-fat diet, body weight increased from 24.0 +/- 1.0 to 35.9 +/- 4.9 kg, mean arterial pressure increased from 83 +/- 5 to 100 +/- 4 mm Hg, cardiac output increased from 2.86 +/- 0.27 to 4.45 +/- 0.55 L/min, and heart rate rose from 68 +/- 5 to 107 +/- 9 beats per minute. Associated with the hypertension was an increase in cumulative sodium balance to 507 +/- 107 mmol after 35 days and a rise in sodium iothalamate space, an index of extracellular fluid volume, to 131 +/- 4% of control. Sodium retention was due to increased tubular reabsorption, because glomerular filtration rate and effective renal plasma flow increased throughout the 5 weeks of the high-fat diet, averaging 135 +/- 4% and 149 +/- 19% of control, respectively, during the fifth week of the high-fat diet.(ABSTRACT TRUNCATED AT 250 WORDS)

HPLC determination of rubber septum contaminants in the iodinated intravenous contrast agent (sodium iothalamate).

A simple and rapid method is described for the determination of 2-mercaptobenzothiazole and mercaptobenzothiazole disulfide leached from rubber closures into the iodinated contrast medium (sodium iothalamate). The contaminants were extracted with methylene chloride and analyzed by high-performance liquid chromatography using ultraviolet detection at wavelengths of 272 and 328 nm. The structures of the impurities were confirmed unequivocally by mass spectrometry. The minimum detectable level was 1 microgram/100 mL (0.01 ppm). The quantitation of contaminants leached from rubber stoppers provides a means for evaluating possible health risks of the extractables.

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.

Three-dimensional computed tomographic imaging of the pelvicaliceal system: analysis of factors influencing image quality.

We analyzed 3-dimensional (3D) computed tomographic images of the pelvicaliceal system obtained in 25 patients after opacification of the collecting system by retrograde ureteric or intravenous (IV) infusion of sodium iothalamate. 3D images were reconstructed using the data from nonoverlapping 5-mm sections taken on an Elscint 2400 scanner. Factors contributing to poor image quality were: artifacts caused by contrast in the collecting tubules, underfilling or overdistension of the pelvicaliceal system with contrast, movement of the patient and severe hydronephrosis. Satisfactory 3D images of the pelvicaliceal system can be obtained by retrograde ureteric infusion of 5% w/v sodium iothalamate at 20 cm H2O, or by IV injection of 50 ml of 70% w/v sodium iothalamate. Abdominal compression should be applied 10-15 min after the IV injection of contrast, and the computed tomographic examination should commence 20-30 min after the injection. It is imperative that the patient lie completely still and breathe normally to avoid movement of the kidneys. 3D computed tomographic imaging of the pelvicaliceal system may become a valuable adjunct to the preoperative planning and performance of percutaneous nephrolithotomy.

Plasma osmolality, iodine concentration and urographic images following high and low osmolar contrast media

Three contrast media (sodium iothalamate, iopamidol and sodium/methylglucamine ioxaglate) in a dose of 240 mg iodine per kilogram of body weight were compared in clinical urography. The ionic monomer sodium iothalamate was the only medium to significantly elevate the plasma osmolality though it returned to normal values within 4 min. All three media exhibited first order linear kinetics. When corrected for the effects of diuresis, sodium iothalamate was shown to give the highest urinary iodine concentrations. On visual scoring sodium iothalamate produced better nephrograms and overall urograms than either of the low osmolar agents.

Radiographic quality and patient discomfort in sialography: comparison of iohexol with iothalamate.

We have compared the usefulness of a newly developed, low osmolality contrast medium, Omnipaque 350 (75.49% iohexol, 350 mgI ml-1), for sialography with one of the established, Angioconray (80% sodium iothalamate, 480 mgI ml-1), in a double-blind, prospective randomized clinical trial in 80 patients. The diagnostic quality of the sialograms, pain during the procedure and discomfort subsequently were investigated. There was no difference in either group between the number of sialograms judged as diagnostically useful, although those of excellent quality were significantly more frequent in the Angioconray group. The level of pain on injection of the medium was significantly lower in the Omnipaque group. Eighteen per cent of the patients with Omnipaque had severe or moderate pain on injection of the contrast medium, while 63% had such pain with Angioconray. There was no difference in postprocedural discomfort between the two contrast media. We concluded that the low osmolality contrast medium is more favourable for sialography despite its lower iodine content.

Comparison of a single-injection technique and inulin clearance for determining glomerular filtration rate in the sheep

Glomerular filtration rate (GFR) was assessed over a 2 h period by the clearance of inulin (Cin) and in the subsequent 2 h period by a single-injection technique using radiolabelled sodium iothalamate (Ciot) or chromium-EDTA (CEDTA). Regression analysis yielded a significant correlation (P less than 0.05) between the standard clearance technique and the single-injection method, with the relationship Ciot = -10.67 + 1.25Cin with a significant correlation coefficient of r = 0.71 (P less than 0.02). There was better agreement between clearance values of inulin measured on successive days than between values determined by the single-injection technique on successive days. Cin remains the method of choice in sheep.

The effect of sodium iothalamate on the vascular resistance of the isolated perfused rat kidney

The direct effects of sodium iothalamate on renal vascular resistance (RVR) were examined using the isolated perfused rat kidney experimental model. A concentration-dependent biphasic change in RVR was produced with the hyperosmolar solution of sodium iothalamate [(Conray 420), 420 mgI/ml, 2500 mOsmol/kg/H2O]. The response characterized by an initial fall followed by a prolonged increase in RVR on discontinuation of the iothalamate infusion. No significant change in RVR was observed when iothalamate was infused as an iso-osmotic solution (60 mgI/ml, 280 mOsmol/kg/H2O) at a rate of 0.525 ml/min. to produce a concentration of 4.2 mgI/ml in the renal perfusate. We conclude that sodium iothalamate can exert direct biphasic effects on RVR which are mediated by its hyperosmolality rather than its chemical content.

Ratio of acentrics to dicentrics in human lymphocytes exposed to X rays and misonidazole

A 0.8 mM concentration of misonidazole was added to human blood samples before exposure to graded X-ray single doses, in order to investigate the dependence of the frequency ratio of acentrics to dicentrics, produced in lymphocytes, on treatment with radiation, the substance and the combination of the 2 agents. The results confirm the findings of a previous experiment carried out using sodium iothalamate, showing that this ratio is markedly influenced by the relative action of the physical and the chemical agents, especially at low radiation doses, because of the enhancement of the frequency of acentrics, and not of dicentrics, caused by the presence of the drug compared to the spontaneous level.

Oxygen free radical involvement in urinary Tamm-Horsfall protein excretion after intrarenal injection of contrast medium.

To discover whether the increase in urinary excretion of Tamm-Horsfall protein (THP) is mediated by oxygen free radicals generated after injection of contrast medium, the authors tested the hypothesis that inhibition of oxygen free radical production after injection of sodium methylglucamine diatrizoate or iothalamate sodium diminishes urinary THP excretion. In three groups of dogs, kidneys received continuous infusions of either superoxide dismutase (SOD) and normal saline (six dogs), heat-inactivated SOD and normal saline (six dogs), or normal saline alone (four dogs). Urinary THP excretion, glomerular filtration rate, renal blood flow, mean arterial pressure, and renal venous malondialdehyde concentrations were measured before and after administration of contrast medium to each kidney. During the postcontrast period, SOD significantly attenuated the increase in urinary THP excretion, accompanied by an attenuated increase in renal venous malondialdehyde concentration. Heat-inactivated SOD did not attenuate renal hemodynamics or urinary THP excretion. The use of another contrast medium, iothalamate sodium, similarly increased urinary THP excretion. These results show that intrarenal administration of contrast medium induces a transient increase in urinary THP mediated in part by oxygen free radical damage to the kidney. Thus, THP may be a marker of renal tubular injury after injection of contrast medium.

A large trial of intravenous Conray 325 and Niopam 300 to assess immediate and delayed reactions

The trial was designed as an investigation into the incidence of both immediate and delayed reactions to the intravenous administration of Conray 325 (sodium iothalamate) (844 patients) and Niopam 300 (iopamidol) (855 patients) for urographic examination. Information was obtained from questionnaires returned by patients about a week after their examination, with a response rate of 81%. Significant differences were found in the incidences of both types of reactions to the two media with respect to nausea and vomiting, arm pain, and taste in the mouth, which was commoner in patients receiving Conray 325, whereas the incidence of delayed skin rashes and parotid swelling was commoner with Niopam 300. The occurrence of a flu-like illness, so-called "iodism", was found to be equal for the two contrast media.

Paravertebral Somatic Nerve Block

The spread of solution after a standardized paravertebral injection was studied to determine the precision and predictability of paravertebral spread. The spread of 5 ml of a solution of radiological contrast medium (sodium iothalamate) and local anesthetic mixture after 45 (34 thoracic, 11 lumbar) paravertebral injections was studied in 31 patients by radiography and computed tomography and correlated with the clinical effects. Spread confined to the paravertebral area occurred after only eight (18%) injections. Spread was epidural after 31 (70%) injections and exclusively so in 14 (31%) injections. Mean sensory loss was greater after epidural spread, but a wide range of sensation loss was observed with all patterns of spread. Intrapleural spread occurred after three injections, as did spread into the psoas muscle. In addition, measurements were made of 114 paravertebral spaces in 20 patients by means of computed tomography. Dimensional factors identified as possibly leading to complications of a paravertebral injection included narrow width of the thoracic transverse processes (mean, 3.18 cm; range, 2.1-4.2 cm) and the wide range in paravertebral dimensions. The distance from bony landmarks to pleura frequently fell outside the limits recommended by many standard texts. We conclude that the spread of a small volume of solution after paravertebral injection is imprecise and unpredictable. Neurolytic and diagnostic paravertebral injections performed without the aid of radiological imaging and contrast media should be regarded as hazardous and interpreted with extreme caution.

腰部硬膜外造影法の検討 Ｉｏｈｅｘｏｌを使用して

Recently non-invasive imaging study of spinal canal had been well developed, but as for lumbar disease, examination with radio-opaque media is still needed in many cases. Lumbar peridurography is one of them which can be done in out-patient clinic easily. Sodium iothalamate has so far been used in many cases, but it sometimes causes severe pain during and after procedure. We have been using iohexol for lumbar peridurography since October 1987. 81.4% of patients in the group using iohexol (group 1) showed excellent or good contrast, and 68.4% of those using iothalamate (Group 2). Concerning about pain during and after procedure, only 10.9% of group 1 patients complained moderate or severe pain, whereas the rate was 35.8% in group 2. We concluded that iohexol gives more benefit than iothalamate in lumbar peridurography. We also discuss about Computed Tomography after lumbar peridurography, regarding to its diagnostic usefullness. It proved to be useful in making diagnoses in a few cases.

Ventilatory function during urography: a comparison of iopamidol and sodium iothalamate

The effects on respiratory function during intravenous urography of the ionic contrast medium sodium iothalamate and the non-ionic contrast medium iopamidol were compared. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were recorded in 37 non-atopic patients referred for intravenous urography. Nineteen patients received iopamidol and 18 patients received sodium iothalamate. Both the sodium iothalamate and the iopamidol groups showed a significant fall in FEV1 and FVC (P less than 0.001). The reductions in FEV1 and FVC were comparable and were not symptomatic. The differences in the percentage changes of the FEV1 and FVC in the iopamidol and the sodium iothalamate groups were not statistically significant (P greater than 0.5 and P greater than 0.1 respectively). No significant change in the ratio of the FEV1 and the FVC was demonstrated in either the iopamidol or the sodium iothalamate groups. Both the ionic and the non-ionic contrast media produced a measurable but asymptomatic and biologically insignificant fall in static ventilatory function. Bronchospasm does not appear to be an important contrast-induced effect in non-atopic individuals. Iopamidol offers no advantage over sodium iothalamate with respect to ventilatory effects in non-atopic patients undergoing intravenous urography.

Comparison of CT and MRI brain tumor imaging using a canine glioma model

A canine gliosarcoma model was used to study the effectiveness of magnetic resonance imaging (MRI) with gadolinium contrast enhancement in defining the histologic margins of brain tumors. The effectiveness of this technique was compared to conventional computed tomography (CT) using iodinated contrast enhancement. Cultured canine gliosarcoma cells were injected into the left hemisphere of adult mongrel dogs. The dogs developed brain tumors and progressive clinical signs. Serial MRI with and without gadolinium diethylene triamine penta-acetic acid was compared to serial CT with and without sodium iothalamate obtained on the same days. After the final scans, animals were sacrificed; the brains were removed and processed for routine histopathologic study. All tumors were visualized with contrast-enhanced MRI which proved most sensitive. Gadolinium di-ethylene triamine penta-acetic acid caused bright enhancement of tumors in a distribution that consistently corresponded to areas of pathologically proved tumor infiltration. Gross and microscopic autopsy findings correlated better with MRI than with CT which tended to produce poorer resolution and underrepresent the size of viable tumor. Gadolinium-enhanced MRI is more accurate than unenhanced MRI, unenhanced CT, or enhanced CT in defining the histologic margins of tumors.

Cecal filling and defecation of chickens infected with Eimeria tenella

White Leghorn cockerels, 11 to 22 days old, were inoculated each with a single oral dose of 4–5 × 10 4 sporulated oocysts of Eimeria tenella. Radiographic study of urinary backflow in infected chickens injected with sodium iothalamate subcutaneously indicated that retrograde movement of ceca was impaired particularly 7, 10, and 14 days after infection. No inflow was noted 7 days after infection when barium sulfate was inoculated into cloaca. Weight of cecal contents examined 7 days after infection was significantly smaller than uninfected control. Number of cecal feces was counted every 24 h beginning 4 through 14 days after infection. The counts in infected birds were significantly fewer than uninfected control 8, 9, and 10 days after infection. Outflow of cecal contents was studied in chickens surgically injected with barium sulfate into cecum 7 days after infection. Radiographic study indicated that most of uninfected control ceca excreted or evacuated the medium between 10 and 24 h after injection, while a few infected birds cleared ceca during the same period.

Renal hemodynamic, fluid volume, and arterial pressure changes during hyperproteinemia.

The chronic effects of hyperproteinemia on renal hemodynamics, fluid volume, and arterial pressure were determined in six conscious dogs over a 32-day period. Plasma protein concentration was increased by intravenous infusion of approximately 300 ml/day of previously collected autologous plasma, and the responses to changes in sodium intake were studied. By the end of a 9-day period of hyperproteinemia and normal sodium intake, plasma protein concentration had increased 2.2 g/dl, plasma colloid osmotic pressure had increased 7-8 mmHg, mean arterial pressure had increased 12 mmHg, glomerular filtration rate (GFR) had increased 15%, estimated renal plasma flow (ERPF) had increased 51% primarily due to renal vasodilatation, and filtration fraction had decreased 23%. Also, sodium balance was negative, water balance was positive, sodium iothalamate space had increased, plasma sodium concentration had decreased, and the relationship between mean arterial pressure and urinary sodium excretion was shifted to the right along the arterial pressure axis. In conclusion, long-term increases of plasma protein concentration result in a marked increase in ERPF as well as significant increases in GFR, extracellular fluid volume, and arterial pressure.

Neurological morbidity of arch and carotid arteriography in cerebrovascular disease. The influence of contrast medium and radiologist.

A prospective study of 230 arch and carotid arteriograms in 229 patients with symptomatic cerebrovascular disease revealed that neurological morbidity was not significantly affected by patient age, nature of neurological symptoms, duration of procedure, volume of contrast medium or degree of arterial stenosis. The total neurological morbidity of 132 examinations carried out with non-ionic contrast medium (iohexol) was slightly lower than that of 98 examinations carried out with ionic contrast medium (meglumine and sodium iothalamate) but the difference was not statistically significant. However, the morbidity of 185 examinations performed by an experienced vascular radiologist was significantly lower (p less than 0.025) than the morbidity of 45 examinations performed by a series of radiologists in training and the mean time required for the procedure was 18 min longer in the latter group (p less than 0.001). These findings suggest that the neurological morbidity of arch and carotid arteriography in patients with cerebrovascular disease depends largely upon catheter technique and will not be significantly reduced by the use of non-ionic contrast medium.

Knee arthrography: effects of various contrast media and epinephrine on synovial fluid.

Changes in synovial fluid leukocytes, total protein, and total complement were studied in 58 patients after they underwent single contrast material-enhanced knee arthrography with ionic (sodium iothalamate, sodium meglumine diatrizoate, meglumine iothalamate) and nonionic (iopamidol, iohexol) contrast media. In 30 of 58 cases, 0.3 mg epinephrine was also injected. In patients examined without epinephrine, a significant increase in the number of leukocytes was observed when sodium iothalamate and sodium meglumine diatrizoate were used. When administered with epinephrine all ionic compounds produced significant leukocytosis; articular reactions were most evident in patients examined with sodium salts. No inflammatory changes in the synovial fluid were observed when nonionic compounds were used. These data suggest that sodium-containing compounds produce a greater reaction in the joint compared with other contrast media, nonionic compounds are better tolerated by the joint, and epinephrine increases the articular reaction to ionic contrast media.