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.

Polymer waveguide overlays for side-polished fiber devices.

Several polymers often used as hosts in guest-host organic thin-film systems were investigated for their suitability as overlays for side-polished fiber (SPF) devices. Good optical quality, ~10-mum-thick films were fabricated by spin coating and applied to SPF's by use of a decal deposition technique to produce passive devices such as channel-dropping (CD) filters, bandpass filters, and polarizers with good throughput and high contrast ratios. The main CD features can be quantitatively explained by a weak coupled-mode model. SPF structures with doped overlays were also examined. These measurements provided a means of determining several SPF device parameters and also allowed estimates of the nonlinearities required to make all-optical and electro-optic devices.

Fabrication of a side-polished fiber polarizer with a biref ringent polymer overlay.

The fabrication of an in-line fiber polarizer consisting of a side-polished fiber (SPF) with a birefringent polymer thin-film overlay, polyvinyl carbazole, is described. Typical devices had <0.5 -dB insertion loss and extinction ratios of ~36 dB. A weakly coupled waveguide model that accurately describes these SPF-thin-film overlay devices and guides in their fabrication is also presented.

Formation of transverse spatial ring structures in increasing-absorption optical bistability.

We report the observation of transverse spatial ring structures in the transmitted beam profile using a thin CdS platelet that exhibits increasing-absorption optical bistability. The observed ring structure is in good agreement with our theoretical predictions.

The sero-prevalence of toxoplasma antibodies in human and selected livestock species in Jamaica - abstract

Results of an island-wide survey of human and selected livestock species in Jamaica during the period January to August, 1987, demonstrated signficant exposure rates in all species surveyed. The sampling frame for animals and humans was unrelated to clinical signs of the disease and therefore may present an unbiased indication of Toxoplasmosis in the Jamaican animal and human populations. Toxoplasma titres, determined by the Indirect Haemagglutination Test, were considered positive at a titre of 1:64. The overall prevalence rate was 42 percent. The sero-prevalence rates found for each species were: cattle, 16 percent: dogs, 31 percent: sheep 40 percent: horses, 41 percent: goats, 56 percent: cats, 56 percent: and, humans, 48 percent. The highest sero-prevalence rates occurred in goats and cats with the lowest occurring in cattle. The high titres found in some species probably suggests current active, or recent, infection with Toxoplasma. How man acquires this particular zoonosis in Jamaica remains obscure. The possibility of a spatial relationship between the high sero-prevalence rates in goats, cats and humans clearly requires further investigation. The true incidence and prevalence rates of Toxoplasmosis in both humans and animals in Jamaica remain largely undetermined and the economic and public health significance unknown (AU)

Effect of fenofibrate treatment on plasma lipoprotein lipids, high-density lipoprotein cholesterol subfractions, and apolipoproteins B, AI, AII, and E.

In this segment of a multicenter study, 36 hypercholesterolemic patients were randomly assigned to fenofibrate or placebo treatment to assess effects on plasma concentrations of lipoprotein cholesterol and triglyceride, high-density lipoprotein-cholesterol subfractions, and apolipoproteins E, B, Al, and All. All of these factors are of known or potential value in determining the patient's risk of arteriosclerosis. Observations were made during initial screening and placebo phases, a 24-week, double-blind treatment phase, and a subsequent 24-week, open-label fenofibrate phase. There were three possible expressions of fenofibrate efficacy. Changes in lipoprotein cholesterol and total triglyceride concentrations observed in these patients were very similar to those seen with the larger multicenter cohort: total triglyceride levels decreased 38 to 46 percent, low-density lipoprotein cholesterol levels decreased 13 to 20 percent, and high-density lipoprotein cholesterol levels increased 4 to 13 percent. Triglyceride concentrations were significantly reduced (p less than 0.01) in very low-density lipoprotein (50 to 56 percent, similar to those of total triglyceride and very low-density lipoprotein cholesterol), and in low-density lipoprotein cholesterol levels (17 to 21 percent). A slight but statistically insignificant decrease in high-density lipoprotein triglyceride was observed (9 to 15 percent). High-density lipoprotein2 cholesterol levels did not change significantly, whereas high-density lipoprotein3 cholesterol levels increased 8 to 16 percent, accounting for all of the increase in high-density lipoprotein cholesterol. Apoprotein All levels increased significantly (13 to 20 percent) whereas those of apolipoprotein Al did not, consistent with an increase in high-density lipoprotein3 levels, where apolipoprotein All is more abundant relative to apolipoprotein Al than in high-density lipoprotein2. Apolipoprotein B levels decreased 20 to 26 percent and those of apolipoprotein E went from 29 to 34 percent, relative to the 16 to 20 percent decreases in very low-density lipoprotein and low-density lipoprotein triglyceride and cholesterol levels. Five patients with combined elevations of triglyceride and low-density lipoprotein cholesterol treated with fenofibrate, had reductions primarily in triglyceride, total apolipoprotein E (50 percent reduction), and apolipoprotein B (18 percent) levels. High-density lipoprotein3 cholesterol levels increased 19 percent and high-density lipoprotein2 cholesterol levels were unchanged. Low-density lipoprotein cholesterol levels declined slightly in four patients and a slight rise was observed in a fifth patient.(ABSTRACT TRUNCATED AT 400 WORDS)

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.

Chordomas: their CT appearance in the cervical, thoracic and lumbar spine.

We reviewed 25 CT scans of 21 patients who had chordomas in the cervical, thoracic, or lumbar spine. Nine patients were studied at the time of initial presentation and 12 after tumor recurrence. All scans showed vertebral body destruction coupled with an associated soft tissue mass located anteriorly or laterally. Additional CT findings included septated areas of low attenuation within the tumor, amorphous soft tissue calcification, tumor extension into the spinal canal, disk space involvement, and contrast enhancement.

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.