Survey approach to estimating demand for physician assistants

A national probability sample of physicians was surveyed by mail to provide an estimate of the number of job openings for physician assistants (PAs). The responses were used to undertake an empirical analysis of the factors which influence a physician's decision to hire a PA. Estimates were adjusted to account for survey non-response. This approach may be useful for estimating the employment demand for other types of health workers employed by physicians.It was found that in 1976 there was an unconditional demand for 20.338 PAs and a further conditional demand for 3417 PAs. This contrasts sharply with the fact that as of March 1977 only 4845 PAs had graduated from training programs. Approximately 53% of this employment demand was from physicians in the primary care specialties (general/family practice, obstetrics/gynecology, internal medicine, and pediatrics). Of note was the finding that physicians expected to pay PAs a lower salary than was being received in the market place. Further, 27% of physicians not willing to hire PAs indicated lack of knowledge about them as the main reason for not hiring.     

Time-resolved projection angiography after bolus injection of contrast agent

A method for MR angiography after bolus injection of a normal dose (0.1 mmol/kg) of contrast agent is presented. Projection angiograms are acquired with a non-slice selective Snapshot FLASH sequence with a time resolution of 1 s per image or better. Typically 40 to 60 images are acquired consecutively after bolus injection of a contrast agent. The signal from vessels can be separated from background by postprocessing based on the observed temporal evolution of the signal intensities during bolus passage. The subsecond projection MR-DSA is a reliable and robust technique to produce high resolution anatomical images of the vascular system avoiding the necessity of exact timing of the contrast agent bolus. It also supplies functional information about the hemodynamics in the observed region including perfusion.     

Inhaled budesonide reduces lung hyperinflation in children with asthma

Previous studies have shown that asthmatics have hyperinflation as defined by larger total lung capacity. The present study was set up in order to document changes in asthma clinic, airway calibre, airway reactivity and lung volumes after budesonide treatment. After a 2-week run-in period, 28 children with moderate persistent asthma were treated in a double-blind manner either with budesonide (0. 4 mg/day) or placebo for 8 weeks and, thereafter, all patients were treated with open-label budesonide for a further 20 weeks. Symptoms, bronchodilator requirements and airway calibre improved significantly after 8 weeks of treatment ( p < 0. 05 for each) and prolonged treatment did not cause any further improvement. Reduction in hyperreactivity was apparent only after 20–28 weeks of treatment. Total lung capacity decreased along with budesonide treatment in both groups suggesting that early introduction of an inhaled corticosteroid may be useful in the prevention of asthma-related remodelling of the lung and thoracic cage.     

The selection of Chinese hamster cells deficient in oxidative energy metabolism

A selection scheme based on the nutritional requirements of a previously described respiration-deficient Chinese hamster line has been used to isolate new mutants defective in oxidative energy metabolism. Three of the primary characteristics of this type of mutant are (1) a strict dependency on the continued presence of glucose for survival; (2) a drastic reduction in the rate of oxygen consumption; (3) an inhibition of Krebs cycle activity resulting in auxotrophy for asparagine and carbon dioxide. In the case of one cell line which was used (V79), up to 65% of the survivors of a selection were found to possess this phenotype after only one round of selection. By contrast, it proved much more difficult to obtain such mutants from another cell line (CCL16). A preliminary characterization of a number of these mutants is presented.     

Evaluation of a new mineral and trace metal supplement for use with synthetic diets

In an earlier study (Alexander et al., 1974) it was shown that the mineral mixture used in association with a synthetic diet was deficient in zinc, copper, iron, and manganese. A new mixture containing appropriately increased amounts of these trace metals has now been evaluated by means of metabolic balance studies carried out on children with phenylketonuria. This new mixture was shown to be satisfactory for zinc, copper, and iron, but minor changes have been recommended for manganese.     

Response to Schoen

This article uses data from 190 patient records in 18 dental practices to conduct a shortterm assessment of the effectiveness and costs of the Keyes technique, a nonsurgical method for treating and preventing periodontal disease. The results of this study, based on nonexperimental data, suggest that controlled clinical trials are called for in assessing the long-term effectiveness of the Keyes technique. If clinical trials support the study's short-term results, then the Keyes technique would provide a cost-effective alternative to surgery for the prevention and treatment of periodontal disease.     

MACULAR ELECTRORETINOGRAMS: THEIR ACCURACY, SPECIFICITY AND IMPLEMENTATION FOR CLINICAL USE

The pattern and the focal electroretinogram (ERG) are both non-invasive, electrophysiological responses recorded from circumscribed retinal areas and are most easily recorded from the macula. This paper describes how our department has incorporated these tests into our clinical protocol, shows how the recording technique and the method of electrode construction may be improved, and describes the normal limits of the macular responses we obtain. The ERG signal-noise ratio we obtained was better than that of the binocular visual evoked potentials (VEPs) recorded simultaneously. Pattern and focal ERGs, using improved methods of recording, show promise of being a valuable addition to the clinical investigation of subtle maculopathies and some forms of optic nerve dysfunction. Three illustrative cases are described. The first demonstrates normal macular ERG responses with abnormal Ganzfeld ERGs due to peripheral retinal damage. The second reveals differential pattern ERG reduction with normal focal ERG in recent optic neuritis. The third case demonstrates reversible simultaneous loss of Ganzfeld ERGs and macular ERGs in vitamin A deficiency.