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Biomedical subjects

A Stordahl

Publications and source records attributed to A Stordahl.

At least 19 recordsLinked to original sources
PubMed1996

The X-ray contrast medium iodixanol detects increased colonic permeability equally well as 51Cr-labeled ethylenediaminetetraacetic acid in experimental colitis of rats.

BACKGROUND: Non-ionic, water-soluble radiographic contrast media have been suggested as intestinal permeability probes. We studied the permeability of the isosmolar contrast medium iodixanol and 51Cr-labeled ethylenediaminetetraacetic acid (EDTA) from the non-perforated colon after induction of colonic inflammation. METHODS: Colonic inflammation and ulcerations were induced by luminal colonic instillation of trinitrobenzenesulfonic acid, dissolved in 40% ethanol. Controls received saline. Fourteen days later iodixanol, 320 mg I/ml, and 51Cr-EDTA were given as an enema. Urine was collected for the subsequent 6 h and subjected to high-performance liquid chromatography and gamma activity counting. RESULTS: Urinary recovery of iodixanol and 51Cr-EDTA increased gradually with severity of the colonic inflammation. The correlation between iodixanol and 51Cr-EDTA recovery was strong (corr.coeff = 0.97). CONCLUSIONS: Iodixanol shows as good properties as 51Cr-EDTA when used as intestinal permeability probe in the inflamed and ulcerated rat colon. Use of the radiopaque properties of iodixanol enable intestinal probe exposure registration by film or fluoroscopy.

Animals↗
PubMed1995

Increased intestinal permeability for the isosmolar contrast medium iodixanol during small-bowel ischaemia in rats.

BACKGROUND: Intestinal ischaemia may be difficult to recognize in the early stages. Increased urinary recovery of water-soluble contrast medium during and intestinal follow-through has been suggested as a sign of bowel ischaemia. METHODS: Urinary excretion of the isosmolar water-soluble X-ray contrast medium iodixanol was measured after instillation via an orogastric tube in 56 rats with occlusion of the mesenteric blood vessels. RESULTS: Mesenteric venous occlusion caused only minor histologic alterations of the mucosa. High-performance liquid chromatography (HPLC) and X-ray fluorescence analysis measured urinary iodixanol concentrations 10 and 13 times higher than in the groups with mesenteric arterial occlusion than in controls (p < 0.001), and 3 and 4 times higher than in the group with venous occlusion (p < or = 0.05). Correlation between HPLC and X-ray fluorescence measurements of contrast medium in urine was strong (r = 0.98). CONCLUSION: Measuring urinary contrast medium levels during intestinal follow-through may aid in distinguishing bowel ischaemia following mesenteric arterial occlusion from mesenteric venous occlusion and from the normal bowel.

Animals↗
PubMed1994

Referrals for double-contrast barium examination. Factors influencing the probability of finding polyps or cancer.

Predictors of the radiologic detection of colorectal polyps or cancer were studied in 1852 patients referred from primary health care for a double-contrast barium enema. Significant polyp predictors were age 40-79 years (odds ratio (OR), 2.4-5.0) and rectal bleeding (OR, 1.8). Previous colorectal neoplasm, familial history of cancer in general, and male sex were nearly significant predictors of polyps. Significant cancer predictors were age > or = 60 years (OR, 8.6-27.8), rectal bleeding (OR, 2.7), loss of weight (OR, 2.6), and male sex (OR, 2.2). Fatigue and abdominal pain were nearly significant negative predictors for cancer. No association was found between patient delay and the detection of polyps or cancer. Physician delay was significantly shorter in patients with cancer than in cancer-free patients. Age was the most important predictor for the detection of both polyps and cancer, more important than symptoms and history, including family history.

Adult↗
PubMed1993

Double-contrast barium enema versus colonoscopy in the diagnosis of neoplastic disorders: aspects of decision-making in general practice.

A total of 190 patients, referred by general practitioners for a double-contrast barium enema, were subsequently examined with colonoscopy. With colonoscopy and histology as the reference standard, sensitivity, specificity, positive and negative predictive values, and accuracy for the radiological detection of cancer and polyps were calculated. No cancer was overlooked by the radiological examination, but there were four false positives. The overall sensitivity for polyps was 70%, increasing to 81% for polyps > or = 10 mm. The predictive value was 93-97% for the exclusion of polyps. The caecum was reached in 187 patients by double-contrast barium enema (98%) and in 164 patients (86%) by colonoscopy. Lesions in four of 12 patients who had radiological changes were undetected at the first colonoscopy, but a repeat examination showed polyps > or = 10 mm in size. Although colonoscopy is a more sensitive technique for the detection of small mucosal lesions, the general practitioners may, in the vast majority of patients, rely on a negative result for polyps and cancer obtained by the double-contrast barium enema. The latter is linked with a number of false-positive cases, while colonoscopy is associated with technical difficulties; both techniques may lead to repeated examinations, regardless of which was the first choice.

Aged↗
PubMed1992

Experimental colonic inflammation and ulceration. Permeation of a water-soluble contrast medium as a measure of 'disease' activity.

The aim of this study was to investigate the permeation of an isosmolar water-soluble X-ray contrast medium (CM) from the unperforated colon after experimental induction of inflammation and ulceration. One hundred and sixty-five male rats were included. In 110 rats 0.25 ml of 40% ethanol + 15 mg or 30 mg trinitrobenzene (TNB) was instilled into the colon, 7-9 cm proximal to the anus, inducing different degrees of inflammation. Fifty-five rats served as controls and had 0.25 ml saline instilled with the same procedure. At 7, 14, 21, and 28 days 3 ml of the non-ionic CM iodixanol was applied as an enema, and subsequently all urine was collected for the next 4 h. High-performance liquid chromatography analyses of the urine showed a positive relation between the severity of inflammation/ulceration in the colonic wall as assessed by a macroscopic damage score and the amount of CM excreted in the urine. Water-soluble contrast media may have prospects of combining functional tests of intestinal membrane dysfunction with segmental exposure control.

Animals↗
PubMed1991

Urinary excretion of iohexol after enteral administration in rats with radiation injury of the small intestine.

Gut membrane dysfunction after acute and subacute irradiation injury to 10-cm-long small-bowel segments was assessed in 85 rats receiving doses of 17 and 21 Gy. Four and 14 days after irradiation 2 ml iohexol was administered via orogastric tubes, and hourly radiographs were taken. After 8 h, blood and urine were sampled for testing, and the intestine biopsied for light and scanning electron microscopy. Dense opacification of the urinary bladder was seen on abdominal films, and increased serum and urinary levels of iodine were demonstrated by X-ray fluorescence analysis in irradiated animals. Urinary levels were up to 20 times higher than in controls 4 days after irradiation, subsiding after 14 days. The effects were prolonged in the 21-Gy group. Our results indicate that measurement of iodine levels in serum and urine may be helpful in assessment of bowel injury in the course of irradiation treatment to pelvic or abdominal organs.

Animals↗
PubMed1988

Water-soluble contrast media compared with barium in enteric follow-through. Urinary excretion and radiographic efficacy in rats with intestinal ischemia.

The local effects and radiographic efficacy of four water-soluble contrast media, barium and saline were evaluated in 91 anesthetized rats with a ligature applied to the anterior mesenteric artery and vein via laparotomy. The rats were observed for 8 hours after instillation of 3 mL of test substance via oro-gastric tube. Radiographs were taken after 1, 4 and 8 hours of observation. After 8 hours, the intestines were weighed, a biopsy was done for light microscopy, and blood and urine were sampled for testing. The roentgen contrast media caused dehydration and increased influx of fluid into the small bowel lumen in proportion to their osmolality. They diluted the bowel contents, enhanced their progression and distended the bowel walls. The diagnostic qualities of radiographic films were better using the new, low-osmolal contrast media than using either barium or sodium diatrizoate. The water-soluble contrast media were excreted in the urine, as demonstrated by dense opacification of the urinary bladder on abdominal films, and increased iodine concentrations at x-ray fluorescence analysis of the urine. This may be useful clinically in detecting bowel ischemia.

Animals↗
PubMed1988

Comparison of water-soluble contrast media and barium in rats with small bowel obstruction or ischemia.

The experimental results from comparing the low-osmolar radiographic contrast media (CM) iohexol, iodixanol, and ioxaglate to the hyperosmolar CM sodium diatrizoate or barium for enteric follow-up examination in rats, suggest that low-osmolar CM are the better alternatives for use in examinations of obstructed small intestine. Excretion of iodine to the urinary bladder in rats with acute intestinal ischemia indicates that water soluble CM may be helpful in the discrimination between this serious disease and simple obstruction of the small intestine.

Animals↗
PubMed1988

Urinary excretion of enteral iohexol in rats with intestinal ischaemia. The influence of size of ischaemic area and duration of exposure to contrast medium.

The urinary excretion of iohexol instilled via orogastric tube was evaluated in rats with ischaemic intestinal segments, simple bowel ligature, and normal bowel. The rats were observed for periods of 1, 2, 3, 4, 5, 6, and 8 h, respectively, after the instillation of 3 ml of contrast medium. Radiographs and blood and urine tests were taken at the end of each observation period. Distinct radiographic opacification of the urinary bladder of the rats with intestinal ischaemia was demonstrated already 2 h after the administration of contrast medium and onwards. Concurrently high iodine concentrations in the urine and serum were measured by an X-ray fluorescence technique. The bladder opacity and iodine levels in the urine varied in close proportion to the length of ischaemic bowel irrespective of the duration of enteric exposure to contrast medium. Overall mean urinary iodine levels were approximately 11 and 32 times that of normal controls in animals with ischaemic bowel segments of 15 and 45 cm, respectively. In comparison, the overall mean serum level in rats with 45-cm ischaemic segments was 16 times that of normals. The clinical implications are discussed.

Animals↗
PubMed1988

The effects of water-soluble contrast media on luminal distension and blood flow in closed loops of small bowel in minipigs.

The effects of iohexol, sodium diatrizoate, and physiologic saline on intestinal distension and circulation were observed for 8 h in nine minipigs with closed-loop obstruction of the small bowel. The two contrast media led to an elevation of intraluminal pressures when initially instilled at pressures above 35 mm Hg. These elevated pressures were not high enough to cause rupture of the bowel wall. Both contrast media caused severe mucosal ischaemia as judged from histologic sections, loops containing sodium diatrizoate more so than iohexol. The blood circulation of the bowel wall, examined by laser Doppler flowmetry, was after 6 to 8 h reduced to about 10% of the values of non-obstructed bowel at intraluminal pressures of about 70 mm Hg in the loops with iohexol and sodium diatrizoate. The correlation to osmolality was obvious when compared with concurrent observations in the loops with physiologic saline. In the bowel loops filled with physiologic saline the pressure fell to 5 mm Hg after 8 h, regaining approximately one-third of pre-instillation levels of blood flow. On microscopy these bowel loops had a nearly normal mucosa.

Animals↗
PubMed1988

Urinary excretion of iohexol administered enterally in rats with intestinal ischaemia. A transmural and transperitoneal route of transport.

Serum and urinary levels of iohexol (Omnipaque) were evaluated in 20 rats with 1.5 ml of contrast medium injected into closed segments of ischaemic small bowel. Ten rats had the small intestine situated inside, and 10 rats outside, the peritoneal cavity. Radiographs were taken every hour, and blood and urine were sampled for testing at the end of the 4-h observation period. A marked increase in opacity of the urinary bladder was seen on radiographs during the observation period in the rats with the bowel laid inside the peritoneal cavity. Correspondingly high concentrations of iodine in the urine and serum were measured by the X-ray fluorescence technique. In comparison, the animals with the bowel placed outside the peritoneal cavity had only traces of contrast medium in serum and urine. These differences between the two groups of rats were highly significant (p less than 0.001). The chief route of transport of contrast medium (greater than 90% of the total absorption) was transmurally and transperitoneally from the lumen of ischaemic bowel to blood before subsequent excretion via the kidneys.

Animals↗