Radiation dose enhancement therapy with iodine in rabbit VX-2 brain tumors.

Loading tissue with iodine enhances the radiation dose absorbed from low energy X-rays. In order to test whether this is a useful procedure for treating brain tumors, we infused radiographic contrast media into rabbits carrying VX-2 brain tumors and delivered 15 Gy of 120 kVp X-rays in 3 fractions to the tumor. From CT scans we estimated that the dose enhancement was approximately 30%. The median survival times, after tumor detection on CT, of untreated rabbits, treated with radiation alone, and treated with radiation plus contrast media were 3, 25.5, 38.5 days, respectively. The repeated infusion of contrast media, 3.5 g of iodine per kg of body weight, did not affect kidney function as measured by serum creatinine levels. This method of enhancing radiation dose in brain tumors therefore appears promising.

Cytogenetic effects of contrast material: diatrizoate versus iothalamate.

Acentric chromosome fragments produced in cells by irradiation or other agents give rise to micronuclei in daughter cells. The micronuclei can be readily counted in large numbers of cells thereby providing a sensitive measure of chromosome aberrations. Previous studies have shown a consistent elevation of micronuclei count following the use of diatrizoate contrast materials. This study was undertaken to compare the micronuclei counts of patients receiving sodium iothalamate with those receiving sodium diatrizoate. Our results indicate that sodium diatrizoate produced significantly greater cytogenetic damage than the sodium iothalamate agents.

Induction of micronuclei in lymphocytes of patients undergoing excretory urography with ioversol.

RATIONALE AND OBJECTIVES: The hypothesis that nonionic contrast medium administered during excretory urography may cause cytogenetic damage was tested. METHODS: Micronuclei were scored in peripheral blood lymphocytes obtained from 33 patients before and after excretory urography with ioversol, a nonionic contrast medium. RESULTS: The examination resulted in a highly significant (sign test, P = .005) increase in the median (range) counts of micronuclei per 1,000 binucleate from 18 (0 to 31) before to 24 (5 to 40) after excretory urography. CONCLUSIONS: Nonionic ioversol produces a statistically significant increase in the chromosome damage of lymphocytes from patients undergoing excretory urography. This increase is similar to that reported for the ionic contrast media, ioxaglate and iothalamate, and equal to that produced by 6 to 7 cGy of 100-kilovolt x-rays.

Nephrotoxicity of epinephrine-assisted venography.

A retrospective study was performed to determined the nephrotoxicity of epinephrine-assisted venography (EAV). The results showed an increase in the serum level of creatinine (sCr) up to five days after EAV in 67% of patients, in comparison with 16% in patients who had other types of renal angiography. Microscopic examination of renal specimens from patients who had undergone EAV showed vacuolization of the epithelial cells of the proximal tubules. Risk factors for acute renal failure that have been described in the literature were not statistically significant in this study. These findings suggest that EAV is a more nephrotoxic procedure than renal angiography without EAV.

Development of rabbit brain tumor model for radiologic research.

A rabbit brain tumor model using transplanted VX-2 carcinoma had an 85% rate of successful implantation. Rabbits lived 8.5 +/- 1.3 days. The tumor doubling time was 0.5 to 2.6 days. Some tumors were shown as early as four days after implantation and all tumors were seen by ten days after implantation. Two of three rabbits receiving radiation therapy to the tumor had significant extension of life. This model is a useful radiologic research tool.

Meta-analysis of increases in micronuclei in peripheral blood lymphocytes after angiography or excretory urography.

Norman, A., Cochran, S. T. and Sayre, J. W. Meta-analysis of Increases in Micronuclei in Peripheral Blood Lymphocytes after Angiography or Excretory Urography. Radiat. Res. 155, 740-743 (2001). Meta-analysis of 10 studies confirms a significant increase in the frequency of micronuclei in peripheral blood lymphocytes after angiography or excretory urography; the weighted average increase is 4.2 (95% confidence interval 2.8-5.6) per 1000 binucleate lymphocytes, about the same increase in micronuclei as that produced in vitro by a diagnostic X-ray dose of 4 cGy. The analysis failed to reveal a significant effect of the specific contrast medium used in the X-ray examinations on the increased frequency of micronuclei. These results are consistent with the hypothesis that the effect of the contrast media is limited to the enhancement, by the photoelectric effect, of the X-ray dose absorbed by the lymphocytes irradiated while suspended in the contrast medium. Therefore, an estimate of increased cancer risk based on elevated frequencies of micronuclei or chromosome aberrations in peripheral blood lymphocytes may be greatly exaggerated whenever the radiation damage is largely confined to the cells circulating in the blood, as it is in people who have recently had X-ray examinations that use intravenous injections of contrast medium. Such examinations include angiography, excretory urography and CT scans, which are received annually by millions of people.

Complete obstruction of the gastric antrum in children following acid ingestion.

We report on two children who experienced delayed complete obstruction of the gastric antrum following concentrated acid ingestion. Both patients required initial tube gastrostomy and subsequent antrectomy with intestinal reconstruction. Unlike the more common alkaline corrosives, ingested acids tend to spare the esophagus and gastric fundus. While gastric perforation and vascular collapse may occur immediately following overwhelming acid ingestion, the more common course is chronic gastric antral inflammation with subsequent fibrosis and, in some cases, complete stricture. Delayed surgical reconstruction is recommended to permit the acute inflammation and edema to subside.

Advantage of underweight.

Exposure measurements made during a diagnostic radiological study revealed that heavy set patients pay a higher price in absorbed dose than lighter people.

Medical pattern recognition pitfalls in a clinical setting: renal cell carcinoma survival prediction.

Three studies to predict renal cell carcinoma patient survival from tumor textures found in digitized early venous phase arteriograms were successful individually. However, when the three methods were compared, they were not consistent and no single method was clinically useful. The first study predicted 5 yr survival of 37 patients with 87% accuracy. The second study added 29 patients to the data base; the poor survival of the 21 patients who died within 5 yr of diagnosis was predicted with 80.9% accuracy. When 27 of these cases were redigitized with a laser scanner, average survival prediction accuracy was 78%. In these studies, digitization hardware, radiographic technique, normalization methods, window selection, and contrast medium distribution all contributed to differences in the statistics separating poor from good patient survival.

Diagnostic effects of edge sharpening filtration and magnification on digitally subtracted renal images.

The improved appearance of digital radiographs filtered to improve local contrast and sharpen edges has not increased acceptance of these images by radiologists. Furthermore, many radiologists assert that correct diagnosis is not improved with these filtered images. This study was designed to test this assertion for digital subtraction angiograms (DSA) of renal images. Four experiments are described. First, phantom studies identified filters and their parameters thought likely to be acceptable and useful in diagnosing renal images formed by DSA. Second, these filters and parameters were then tested on medical images to assess their acceptance by radiologists. Third, display modes of windowing, positive/negative presentation, and magnification were varied for filtered and unfiltered images to assess preferences of radiologists. Fourth, filtered and unfiltered magnified images were used to test improved diagnosis. In the final experiment, 148 images from 33 renal studies (15 normal, 18 abnormal) were magnified, gray level windowed, and filtered. Diagnosis was not improved by the two edge sharpening filters tested.

Physical pain and the goal of aversively stimulated aggression.

Several studies have indicated that anger arousal elicits instigation to inflict injury, but there is good evidence to date that noninsulting aversive events also create a desire to hurt someone. The verbal hostility or physical aggression displayed in previous investigations of the effects of such aversive stimuli might be expressions of an instigation to hit, but not necessarily to hurt, the available target. Two experiments were designed to demonstrate that painful environmental conditions evoke aggressive inclinations directed toward doing harm even when the available target is not responsible for the suffering. In both studies university women kept one hand in a tank of water that was either painfully cold or much warmer while they delivered rewards and punishments to another woman supposedly in the course of supervising her work. Half of the subjects in each condition were informed that their punishments might hurt their partner, whereas the others were told that these punishments probably would be helpful. In the first experiment the two variables interacted to affect the subjects' behavior only during the first work period. Experiment 2 yielded interaction in both periods for the reward measure. In general, the women exposed to the warmer water tended to deliver the greatest number of rewards when they had been told punishment would hurt, whereas those in the cold-water condition were least rewarding if they had been informed punishment would injure their partner. Citing evidence that a lower number of rewards was somewhat punitive, we conclude that the aversive stimulation had evoked an instigation to do harm, and that the information about the possibility of hurting the partner served as a goal cue facilitating the overt expression of the instigation. Factor analyses of the subjects' feelings in the second study suggested that the women's feelings were organized differently the first and second times they had their hand in the water.

Genitourinary imaging and procedures by the emergency physician.

Optimal imaging of the urinary tract in the Emergency Department does not require sophisticated or rare equipment. The supervising physician must review each ExU, cystogram, or RUG film as it becomes available and decide upon the proper course of action. Indications for contrast studies in injured patients continue to evolve, with a trend away from investigation of stable patients with microscopic hematuria on the first urine. Urethral catheterization and suprapubic cystostomy are complementary options for bladder drainage. Careful attention to details of anatomy and technique allow for success in the majority of patients. There are substantial pitfalls in the diagnosis and treatment of male genital emergencies. The acute treatment of priapism is rapidly changing as understanding of penile physiology becomes more complete. Acute scrotal pathology can be difficult to categorize without surgical exploration. Urologic consultation, therefore, is mandatory in these conditions.

Extracorporeal shock wave lithotripsy: clinical results.

The uroradiological experience with extracorporeal shock wave lithotripsy (ESWL) treatment of over 1,500 urinary calculi is summarized. Percutaneous nephrostomies were needed in 5-50% of ESWL patients depending upon the size and location of stone being treated. Over 25% of percutaneous nephrostomy tracts were subsequently used for other procedures. When staghorn calculi were treated by ESWL, the collaborative efforts of uroradiologists and urologists is mandatory.