Biomedical subjects
Publications and source records attributed to R E Gold.
This paper presents a simple, fast, and accurate afterloading method of delivering high radiation dose to tumors of the biliary tract, using radioactive iridium through a biliary drainage catheter. A Tuohy Borst sidearm adaptor permits concurrent drainage. The dose delivered in this manner can be used to supplement the palliative external beam radiotherapy, with minimal side effect.
Seven patients with vascular rings were evaluated over a 2-year period with intravenous digital subtraction angiography (DSA), which was compared with screen-film aortography or cineangiography. The seven patients were also evaluated with barium esophagography. Six of the seven DSA images were totally diagnostic and one study was only partly diagnostic. Six of the seven vascular anomalies were confirmed surgically. DSA is suggested as an alternative to arteriography in evaluating patients with suspected vascular rings.
A simple and convenient technique is presented for the performance of transluminal brush biopsies of biliary tract lesions. Since a guide wire is maintained in position through the obstruction, the technique can be performed at any time without loss of access to that lesion.
Dermal and respiratory exposure, and erythrocyte and serum acetylcholinesterase activity were monitored on two groups of professional pesticide applicators spraying trees with carbaryl. The mean dermal exposure to the first group was 128 mg hr-1 of carbaryl and the mean respiratory exposure was 0.1 mg hr-1. The maximum percent (%) toxic dose received by the applicators was 0.12% hr-1. The mean exposure to the second group of applicators was 59.4 mg hr-1 dermal and 0.1 mg hr-1 respiratory, for a total of 0.02% toxic dose per hr. It was estimated that 86.9% of the dermal exposure was to the forearms and hands. The rate of exposure to pads placed under the applicators clothing was approximately 1/20 that of pads on the outside of the clothing. Of the body areas monitored, the back received the least rate of exposure. It was determined, in vitro, that 10(-3) M carbaryl would inhibit human serum (pseudocholinesterase) and erythrocyte acetylcholinesterase for at least 72 hr. There was no overall inhibition of acetylcholinesterase activity in the applicators.
Thirty-eight urban volunteers from the Lincoln and Omaha, Nebraska areas were monitored for carbaryl exposure during the summer of 1979. All volunteers were involved in the application of carbaryl incidental to their employment or leisure activities. The investigators made no attempt to affect the method of carbaryl application. The mean rates of carbaryl exposure were 3.85 and 0.26 microgram cm-2 hr-1, respectively, for the outside of the clothing and the skin beneath the clothing; clothing apparently provided an effective barrier to carbaryl penetration. The rate of carbaryl exposure to the hands of applicators was 2.36 and 24.96 micrograms cm-21 hr-1, respectively, for applicators with and without gloves. The maximum dermal exposure recorded in this study was 2.86 mg kg-1 hr-1 which is significantly less than the stimated dermal LD50 value for carbaryl (4000 mg kg-1). The maximum air concentration of carbaryl was 0.28 microgram L-1. Only a small mean decrease was found in the applicators serum (-1.01%) or erythrocyte (-1.39%) acetylcholinesterase activity. Although some applicators had decreases in either serum or erythrocyte acetylcholinesterase activity greater than 20%, an equal number had increases of the same magnitude. The mean total carbaryl exposure to the applicators, expressed as a percent of toxic dose per hr, was 0.01%, with a maximum estimated exposure of 0.08%.
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Histoplasma mediastinitis with complete or partial pulmonary artery obstruction due to compression and/or intraluminal granuloma was diagnosed in five patients and surgically verified in two. The patients, ages 12-27 years, had cough, dyspnea (four cases), and hemoptysis (two cases). Radionuclide imaging showed unilateral absence of pulmonary perfusion and minimal diminution of ventilation. Differentiation of this inflammatory process from other causes of ventilation-perfusion mismatch, for example, congenital hypoplasia and certain acquired causes of arterial obstruction, especially thromboembolism, may be possible by correlating radiographs, laminograms, and clinical history. Angiography can delineate the extent of perfusion impairment and may suggest its cause.
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Gastric angiodysplasias may be more common than previously described, and should be considered when barium studies and endoscopy do not reveal the source of chronic or recurrent upper gastrointestinal hemorrhage. Since these lesions are generally submucosal, angiography is the ideal method to diagnose and show the extent of an angiodysplasia. Magnification angiography and gastric air insufflation aid in making the lesions more apparent and in confirming the diagnosis, but prominent early draining veins can be identified by high-quality nonmagnified selective angiography.
The ischemic leg as the only clinical manifestation of an aortic dissection is rare. Without the usual symptoms of an aortic dissection, this diagnosis may easily by overlooked during routine peripheral angiography for the ischemic limb. Three cases are reviewed in which the patient was thought to have a spontaneous peripheral vascular occlusion, but was later found to have an aortic dissection without the usual thoracic or abdominal symptoms. The radiologist should observe carefully for signs of dissection such as fusiform narrowing of a vessel, nonfilling of branches of the aorta, or displacement of the intima into aortic lumen.
A device for the controlled trimming of plastic specimen blocks for light and electron microscopy is described. Many advantages of previously reported instruments together with 1) a rack and pinion control of knife movement, and 2) a control of rotation of the specimen block at 90 degrees, 180 degrees, 270 degrees, or 360 degrees are incorporated. In conjunction with an ocular micrometer, the device allows accurate removal of thin slices during trimming.
PTA may be the most cost-effective approach to correctable renovascular hypertension. Successful PTA not only lowers the blood pressure, but may also preserve or improve renal function. Patients who are not ideal surgical risks should be considered for this approach if their blood pressure is not controlled or if side effects from antihypertensive drug therapy are disabling. PTA should be performed in consultation with, and with the back-up of, a vascular surgeon.