J. Alfred Rider

Toxicity of parathion, systox, octamethyl pyrophosphoramide, and methyl parathion in man☆

Abstract Experiments in human beings were undertaken to determine the levels of minimal toxicity of parathion, systox, OMPA, and methyl parathion. The study of parathion demonstrated that the level of minimal toxicity is 7.5 mg per day. Between 6.75 and 7.125 mg per day of systox produced minimal toxicity. In the case of OMPA the level of minimal toxicity was 1.5 mg per day. This compound is of further interest in that it was the only compound studied to which the red cell cholinesterase activity was more sensitive than the plasma cholinesterase activity. Although doses as high as 19.0 mg per day were evaluated in the study of methyl parathion, the level of minimal toxicity was not established.

The minimal oral toxicity level for mevinphos in man

Abstract Four groups, of five human volunteers each, were fed various doses of mevinphos daily for 30-day periods to determine its effect on plasma and erythrocyte (RBC) cholinesterase with the following results: 1.0 mg had no effect, 1.5 and 2.0 mg each produced a 20% or greater decrease in RBC cholinesterase on one occasion only, while 2.5 mg produced a steady decrease in RBC cholinesterase reaching a maximum of 25% on the 27th day of administration. None of these doses affected the plasma cholinesterase activity. From these results we conclude that 2.5 mg mevinphos meets the criterion for minimal incipient toxicity, which is defined as the amount producing a decrease of 20–25% below control cholinesterase activity.

Color television gastroscopy: A critical analysis

A highly sophisticated instrumentation for producing and recording vivid endoscopic images by color television has been perfected. Although its present cost will limit its use to large and affluent teaching services, it approaches the ideal of fully exploiting the endoscopic technique.

7198 One hundred consecutive percutaneous endoscopic gastrostomies (pegs) in an elderly (average age 85) high-risk population with zero mortality and no intraoperative complications: a standardized team approach.

Introduction: Since the first percutaneous endoscopic gastrostomy was reported in 1980 for enteral support, there have been a number of studies concerning mortality and morbidity. The mortality rates have ranged from 0 to 2.5%; the incidence of morbidity has ranged form 3 to 5.9% and maybe as high as 17%. We are reporting results from 100 consecutive percutaneous endoscopic gastrostomies (PEGs) in an elderly (average age 85) high-risk population utilizing a standardized team approach. Methods: A 20 FR Microvasive® gastrodome™ was used in all patients. All procedures were done in the G.I. endoscopic suite in one of two private hospitals in San Francisco. The professional team consisted of an endoscopist, a surgeon, an anesthetist, and a G.I. nurse endoscopic assistant. All subjects met the guidelines of the American Society of Gastrointestinal Endoscopy for PEG placement. Appropriate informed consent was obtained. The usual monitoring devices were utilized on the fasting patient. Conscious sedation administered intravenously by the anesthetist consisted of midazolam HCl, fentanyl, or propofol. The endoscopist, in cooperation with the surgeon, placed the PEG tube in the upper epigastrium and fitted it snugly against the interior wall of the stomach which position was verified by a second endoscopic examination. Lapsed time from the first endoscopic insertion to the end of the procedure generally took ten minutes. The skin surrounding the PEG site was covered with bacitracin and a bandage. PEG feedings were begun 24 hours later. Results: The 100 patients ranged in age from 68 to 101 with an overall average age of 85. There were 63 females ranging in age from 69 to 101 with an average of 86.4. The 37 males ranged in age from 68 to 96 with an average of 83.5. They were of high-risk because of numerous medical complications such as hypertension, ASHD, previous CVAs, neurological disorders, anemia, dementia or cachexia. There was no mortality and no intraoperative complications. Conclusion: The proper selection of patients, the experienced and highly competent professional team approach making for quicker and safer procedures, and the use of excellent durable equipment devoid of defects contributed to the overall superior results.