Sachiko T. Cochran

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.

Meta-analysis of Increases in Micronuclei in Peripheral Blood Lymphocytes after Angiography or Excretory Urography

Abstract 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.

Effects of age, sex and diagnostic X-rays on chromosome damage.

The frequency of micronuclei assayed in lymphocytes obtained from 73 young adults increases significantly with the age, but not the sex, of the donor. The dose of medical X-rays absorbed by the lymphocytes in the 2 years before the examination has no significant effect on micronucleus frequency, provided the data are adjusted for age. However, a small significant increase in frequency is associated with X-ray examinations that involve the injection of contrast media into the blood.

Noninvasive Radiological Diagnosis of Renal Vein Thrombosis in Renal Transplantation

Thrombosis of the allograft renal vein is a rare complication of renal transplantation. Of 557 consecutive renal transplants performed between January 1, 1985 and November 30, 1989, 3 cases occurred for an over-all incidence of 0.4%. In 2 cases the diagnosis was made preoperatively with renal scintigraphy and duplex Doppler sonography. No graft was salvaged, despite timely diagnosis in 2 patients. We conclude that the diagnosis of renal vein thrombosis in the renal allograft recipient should be suspected clinically and by the radiographic findings of absent perfusion on renal scintigraphy, and the detection of an arterial signal, albeit abnormal, on duplex Doppler sonography. When diagnosed, nephrectomy appears to be the only treatment.

Nephromegaly in Hyperalimentation

Nephromegaly associated with hyperalimentation and its effect on renal function were studied. Renal size was determined in 44 patients receiving total parenteral nutrition (TPN). Of 26 patients in whom kidney size could be determined before and during TPN, all but one had normal-size kidneys before TPN. Six had no increase in renal size, and kidneys increased in size in 20. One or both kidneys became abnormally large in 9 patients. There was no detectable change in renal function and kidneys decreased in size upon discontinuation of hyperalimentation. Abnormal renal size bore no relation with weight gain or liver function tests.

Trends in Adverse Events from Iodinated Contrast Media

Documentation of adverse events associated with contrast material administration began in the Genitourinary (GU) Section in 1985 and included all computed tomography (CT) scanners by 1988. Only ionic contrast material was used in 1985 and 1986. From 1987 through 1990, both ionic and nonionic agents were being administered by selective use. As of 1991, all intravenous (IV) contrast media administration was nonionic. Adverse events were reported on a standardized form requesting information about the nature of the event and treatment given, the name and amount of contrast material administered, and patient identification. Data collection regarding extravasation of contrast material was added starting in 1993. Data collection regarding gadolinium-based magnetic resonance imaging (MRI) contrast agents also began in 1993. Adverse reactions that were categorized as allergylike include sneezing/nasal congestion, hives/itching/rash/ swelling, laryngeal edema, bronchospasm, pulmonary edema, and anaphylaxis. Other reactions included shaking/chills/fever, seizure, numbness, and malaise/achiness. With the administration of ionic contrast media, nausea/ vomiting and arm pain were also reported. Reactions were graded as mild when no therapy was required, as moderate when therapy was given and the patient was sent home from the radiology department, and as severe when urgent therapy was required and the patient was subsequently followed in the emergency room or admitted to the hospital.

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

RATIONALE AND OBJECTIVESThe hypothesis that nonionic contrast medium administered during excretory urography may cause cytogenetic damage was tested. METHODSMicronuclei were scored in peripheral blood lymphocytes obtained from 33 patients before and after excretory urography with ioversol, a nonionic contrast medium. RESULTSThe 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. CONCLUSIONSNonionic 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.

Renal Cavernous Hemangioma in a Patient with the Acquired Immunodeficiency Syndrome

We describe a patient with the acquired immunodeficiency syndrome (AIDS) who presented with a malignant appearing renal mass. Exploration and radical nephrectomy ultimately revealed benign cavernous hemangioma. The diagnosis of benign lesions can be challengmg when malignancy and infection are highly suspected, as in patients with AIDS. To our knowledge we report the first case of renal cavernous hemangioma associated with AIDS.

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.

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.