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C R Armstrong

Publications and source records attributed to C R Armstrong.

7 recordsLinked to original sources

Right axis deviation as a criterion for echocardiographic evaluation of aircrew candidates.

BACKGROUND: Significant pressures exist in the resource-limited environment of military aviation to select only those candidates for flight training who are both physically able to withstand the demands of the flight environment and likely to complete a career in aviation. As medical technology has advanced, uncertainty has arisen regarding the appropriate use of additional studies in the screening of aircrew candidates. At the Naval Operational Medicine Institute (NOMI), where all U.S. Navy aviation duty candidates' medical qualifications are reviewed, current policy is to perform 2D-echocardiography on all candidates who exhibit a right axis deviation of +95 degrees or greater on their initial electrocardiogram. METHODS: The records of all aircrew candidates referred to the Department of Internal Medicine for evaluation of right axis deviation during the years 1993, 1994, and 1995 were reviewed. A cost benefit analysis was performed to assess the cost effectiveness of using echocardiography to screen candidates suspected of having disqualifying physical defects based on a finding of right axis deviation on electrocardiogram. RESULTS: Of the 69 cases reviewed, only 1 candidate was disqualified due to cardiovascular disease. He suffered from a large atrial septal defect initially discovered on physical examination. CONCLUSIONS: It is not cost effective to use 2D-echocardiography to screen aircrew candidates for disqualifying cardiac defects based on a finding of a right axis deviation of +95 degrees or greater on electrocardiogram.

Adult↗

Hydrogen bonding and specificity. Fluorodeoxy sugars as probes of hydrogen bonding in the glycogen phosphorylase-glucose complex.

The affinities of a large number of deoxy and fluorodeoxy sugars for the glucose binding site in glycogen phosphorylase have been measured, and polarities and relative strengths of the hydrogen bonds at each position have been predicted on the basis of these data. Comparison with the recently refined X-ray crystal structure of the phosphorylase-glucose complex shows a generally good correlation between predicted and observed bond strengths, vindicating this approach to the evaluation of hydrogen bonding. Estimates of the net contributions of hydrogen bonds of different types (neutral-neutral and neutral-charged) are essentially identical with those obtained by a complementary approach on the tyrosyl tRNA synthetase-substrate complex [Fersht, A. R., Shi, J. P., Knill-Jones, J., Lowe, D. M., Wilkinson, A. J., Blow, D. M., Brick, P., Cortes, P., Waye, M. M. Y., & Winter, G. (1985) Nature (London) 314, 235-238]. The carbohydrate binding site structure determined is compared with that recently determined for the arabinose binding protein.

Animals↗

Resource allocation. The cost of care: two troublesome cases in health care ethics.

With the cost of health care rising rapidly, both physicians and administrators regularly face resource allocation decisions. Under these conditions of relative scarcity, the equitable and appropriate distribution of limited resources becomes an ethical as well as a financial issue. Through ethical analysis, physician executives can assist their physician colleagues and fellow administrators to find rationally defensible answers to questions regarding the distribution of limited resources. Six criteria are frequently "weighted in the balance" by ethicists when analyzing whether justice is served in the distribution of a limited resource: need, equality, contribution, ability to pay, effort, and merit. The authors argue that, from an ethical standpoint, the best single criterion upon which one can base an allocation decision is that of merit, defined as the potential to benefit from the investment of additional resources.

Decision Making↗