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Biomedical subjects

J Bentley

Publications and source records attributed to J Bentley.

At least 55 records · Page 3Linked to original sources
PubMed1989

Residents' hours and supervision.

One year of graduate medical education, the internship, had become the norm for graduates of most U.S. medical schools by 1920, and subsequently was adopted by most states as a criterion for licensure. The original concept of a "resident physician" carried with it responsibility for patients 24 hours per day, seven days per week. Recent public and media attention to the issues of residents' supervision and working hours has led to governmental efforts to restrict their hours and set minimum requirements for supervision. New York is the first state to impose specific requirements. The New York recommendations have implications for the concept of graded responsibility for residents, for learning the natural course of illness, and for the need to provide service in hospitals. Further, the recommendations raise four objections: they do not recognize differences by type of specialty or year of training; they might affect the length of time needed to acquire aggregate clinical skills; they affect different types of hospitals differently; and they would have a major effect on physician manpower. Hospitals and residency programs will face several difficult choices in responding to the regulations. To provide its members with guidelines for action, the Executive Council of the Association of American Medical Colleges has issued recommendations for residency hours and supervision, including the use of an 80-hour work-week averaged over four weeks, the continued use of graded supervision of residents in emergency rooms and in inpatient and ambulatory settings, and control of housestaff moonlighting.

Emergency Service, Hospital↗
PubMed1984

Fentanyl preloading for rapid-sequence induction of anesthesia.

Protecting the patient's airway is of paramount importance in the induction of general anesthesia. For the patient at risk of regurgitation of stomach contents, the rapid-sequence (crash) induction provides protection, but at the expense of increased stress response to laryngoscopy and intubation. This stress response is especially dangerous for the patient at risk for myocardial ischemia. The purpose of this study was to examine the efficacy of using low-dose fentanyl (5 micrograms/kg) to reduce cardiovascular and neuroendocrine stress responses to rapid-sequence induction. Thirty patients were randomly assigned to a rapid-sequence induction protocol either with or without fentanyl preloading. Fentanyl-preloaded patients (fentanyl group) received 2 mg/kg of thiopental whereas patients who were not preloaded with fentanyl (control group) received 4 mg/kg of thiopental. Data collected as indices of the stress response included heart rate, systolic, diastolic, and mean blood pressures, and plasma concentrations of catecholamines (epinephrine, norepinephrine, dopamine) and beta-endorphin. Electrocardiograms (modified V5 lead) were monitored for dysrhythmias and ST segment depression. Control patients had higher systolic, diastolic, and mean blood pressures after intubation than did patients given fentanyl (P less than 0.05). Although the incidence of dysrhythmias was decreased by fentanyl (20% vs 42%), this difference was not statistically significant. Plasma concentrations of beta-endorphin and norepinephrine increased significantly in control patients but not in patients given fentanyl (P less than 0.05). Low-dose fentanyl (5 micrograms/kg) reduces some aspects of the stress response to rapid-sequence induction of anesthesia.

Adult↗
PubMed1981

Cimetidine decreases theophylline clearance.

This study tested the hypothesis that cimetidine decreases theophylline clearance. Aminophylline (6 mg/kg) was administered intravenously both before and after cimetidine treatment in 5 healthy adults. Cimetidine (300 mg) was administered orally every 6 h for 2 days before and 18 h after the aminophylline dose. Plasma samples were collected before and for 24 h after each aminophylline dose, and theophylline concentrations were determined by an enzyme-mediated immunoassay technique. Cimetidine significantly decreased theophylline clearance, mean decrease, 39% (3.85 +/- 0.27 L/h control versus 2.34 +/- 0.23 L/h with cimetidine treatment, p less than 0.002). The apparent volume of distribution was unchanged (p greater than 0.5), whereas the elimination rate constant was significantly decreased by a mean of 42% (control, 0.091 +/- 0.013 h-1 versus 0.053 +/- 0.007 h-1 with cimetidine treatment, p less than 0.005). This corresponded to an average increase in elimination half-life of 73% (range, 50 to 97%). Cimetidine probably slowed theophylline elimination by relatively nonspecific inhibition of the hepatic microsomal mono-oxygenase system. This effect may produce clinically significant changes in serum theophylline concentrations.

Administration, Oral↗
PubMed1980

Experimental communicating syringomyelia in dogs after cisternal kaolin injection. Part 1. Morphology.

Intracisternal kaolin injection in dogs usually produces hydrocephalus and out of 16 such dogs 11 have shown enlargement of the central canal of the spinal cord which has proceeded to syringomyelia-like cavities in 7 instances. The morphology of the cavities is described, the absence of ischaemic changes in the cord noted and the occasional communication of the cavities with the spinal subarachnoid space at the level of the filum terminale confirmed. The similarities to human syringomyelia are noted together with important differences in the etiology. The dogs all had arachnoiditis, all had hydrocephalus and all had a radiologically demonstrable communication of the cavities with the 4th ventricle, findings which are unusual in human syringomyelia.

Animals↗
PubMed1979

Stereo-electron microscopy and energy-dispersive x-ray analysis of avian reticulocytes.

Utilizing the techniques of stereo-electron microscopy (stereo-EM) and energy-dispersive x-ray analysis (EDX), we have studied aspects of the ultrastructure of avian reticulocytes. Stereo-EM of thin sections (0.10 to 0.25 mum thick) stained with uranyl and lead revealed the three-dimensional arrangement of 25 nm chromatin fibers on the tangential surfaces of nuclei. Use of the Bernhard staining procedure in combination with stereo-EM permitted a three-dimensional view of the interchromatin spaces and channels leading to the nuclear pores, and of cytoplasmic polyribosomes. With either staining technique we frequently encountered in the cytoplasm clusters and paracrystalline arrays of electron-dense granules with granule diameters approximately 1/2 that of monomer ribosomes. These granules were highly electron-dense in unstained specimens and have been identified as intracellular ferritin on the basis of the similarity of their ultrastructural morphology to that of horse spleen ferritin and their high content of iron as determined by EDX. The possibility that these granules represent toxic products of phenylhydrazine treatment (Heinz bodies) is considered unlikely, since we have demonstrated in this study that Heinz bodies cannot be visualized in unstained preparations, do not reveal the same granular structure, and do not contain significant amounts of iron above background. The occurrence of intracellular ferritin is discussed in light of current concepts of iron transport and storage during erythropoiesis.

Anemia↗