Degradation of ethylene glycol using Fenton's reagent and UV.

Oxidation of ethylene glycol in aqueous solutions was found to occur with the addition of Fenton's reagent with further conversion observed upon UV irradiation. The pH range studied was 2.5-9.0 with initial H2O2 concentrations ranging from 100 to 1000 mg/l. Application of this method to airport storm-water could potentially result in reduction of chemical oxygen demand by conversion of ethylene glycol to oxalic and formic acids. Although the amount of H2O2 added follows the amount of ethylene glycol degraded, smaller H2O2 doses were associated with increases in the ratio of ethylene glycol removed per unit H2O2 added indicating the potential of pulsed doses or constant H2O2 feed systems. Ethylene glycol removal was enhanced by exposure to UV light after treatment with Fenton's reagent, with rates dependent on initial H2O2 concentration. In addition to ethylene glycol, the principle products of this reaction, oxalic and formic acids, have been shown to be mineralized in other HO generating systems presenting the potential for ethylene glycol mineralization in this system with increased HO* production.

Benign metastasizing meningioma. Case report.

A patient with a histologically benign intracranial meningioma was found, at the time of initial presentation, also to have a pulmonary tumor. Fine-needle aspiration cytology of the lung mass was consistent with metastatic meningioma. When resected, the pulmonary tumor was found to be histologically benign. The patient has remained well and disease-free for 28 months. Only four other patients with apparently benign metastasizing meningiomas have been described previously.

Myocardial ischemia during intravenous DSA in patients with cardiac disease.

A prospective study was performed for 48 patients who had histories of angina and were referred for digital subtraction angiography (DSA). Cardiac disease was graded according to the American Heart Association (AHA) functional classification system. Each patient received 2-5 injections of 40-ml diatrizoate meglumine and diatrizoate sodium (Renografin-76, Angiovist-370, or MD-76) at 15 ml per second in the superior vena cava. Of the 28 patients in functional Classes I or II (no or slight limitation of activity), 11% had angina and 32% had definite ischemic ECG changes after the DSA injections. Of the 19 patients in functional Class III (marked limitation of activity), 63% had angina, and 58% had definite ischemic ECG changes after the injections. One patient in functional Class IV (total disability) developed ventricular fibrillation after the second injection. These observed cardiac effects following bolus injections of hypertonic ionic contrast media indicate that special precautions are necessary when performing intravenous DSA examinations on this group of high risk patients.

Nuclear magnetic resonance (NMR) imaging of tumors in the posterior fossa.

Nuclear magnetic resonance (NMR) images were obtained in 12 patients with mass lesions in the posterior fossa and the results compared with X-ray computed tomography (CT). Inversion recovery T1-weighted images demonstrated abnormalities in six of six intrinsic lesions and three of six extrinsic lesions. Spin echo T2-weighted images demonstrated abnormalities in two of two intrinsic lesions and four of five extrinsic lesions. Saturation recovery T1-weighted images were normal in two of two intrinsic lesions and two of four extrinsic lesions. Overall, NMR detected 11 of 12 lesions. Two intrinsic tumors detected by NMR were not detected by CT evaluation. Two small extrinsic tumors required CT gas cisternography for detection.

Nuclear magnetic resonance (NMR) imaging of Arnold-Chiari type I malformation with hydromyelia.

Saturation recovery nuclear magnetic resonance (NMR) images and metrizamide computed tomography (CT) scans were obtained in an adult patient with a clinical history suggestive of syringomyelia. Both NMR and CT studies showed low lying cerebellar tonsils. The CT study demonstrated central cavitation of the spinal cord from the midthoracic to midcervical levels but could not exclude an intramedullary soft tissue mass at the cervico-medullary junction. The NMR images in transverse, coronal, and sagittal planes demonstrated extension of an enlarged central spinal cord cerebrospinal fluid space to the cervico-medullary junction. This was felt to be strong evidence for exclusion of an intramedullary soft tissue mass and in favor of a diagnosis of Arnold-Chiari Type I malformation with hydromyelia. The noninvasive nature of spinal cord and cervico-medullary junction evaluation with NMR is emphasized.

Canine esophageal motor function: effects of arterial and intravenous vasopressin.

The effect of vasopressin infusion on esophageal motor function was evaluated in 11 anesthetized dogs. Gastric fundic, lower esophageal sphincteric, and esophageal body pressures were measured during and after 1 hr infusion of vasopressin into the superior mesenteric artery or a systemic vein. Lower esophageal sphincteric pressures started to decrease significantly 10-15 min after the start of vasopressin infusion, reached the lowest level at 45-60 min, and returned to the control level or higher 1 hr after the end of infusion. No statistically significant difference was found between the effects of intravenous and intraarterial vasopressin infusions. Esophageal body and gastric fundic pressures remained unchanged. The result is inconsistent with the hypothesis that esophageal smooth muscle contractions reduce esophageal variceal hemorrhage during vasopressin infusions.