Why is it so hard to consider personal qualities when selecting medical students?

Abstract

Having ‘good’ doctors is important to everybody. How to select medical students better has been discussed repeatedly for more than seventy years, implying that prevailing methods could be improved. A significant body of research exists about selection methods and their application in medicine. Yet most medical schools world-wide continue to use prior academic performance and cognitive ability as their major criteria for selection, with minor or no consideration of personal qualities and interpersonal skills (possibly assuming they will develop naturally during training and practice). We describe the main methods available for assessing personal qualities of applicants to medical school and have attempted to identify some reasons and systemic disincentives working against their adoption.     

Development and maturation of the fibrous components of the arterial roots in the mouse heart

The arterial roots are important transitional regions of the heart, connecting the intrapericardial components of the aortic and pulmonary trunks with their ventricular outlets. They house the arterial (semilunar) valves and, in the case of the aorta, are the points of coronary arterial attachment. Moreover, because of the semilunar attachments of the valve leaflets, the arterial roots span the anatomic ventriculo‐arterial junction. By virtue of this arrangement, the interleaflet triangles, despite being fibrous, are found on the ventricular aspect of the root and located within the left ventricular cavity. Malformations and diseases of the aortic root are common and serious. Despite the mouse being the animal model of choice for studying cardiac development, few studies have examined the structure of their arterial roots. As a consequence, our understanding of their formation and maturation is incomplete. We set out to clarify the anatomical and histological features of the mouse arterial roots, particularly focusing on their walls and the points of attachment of the valve leaflets. We then sought to determine the embryonic lineage relationships between these tissues, as a forerunner to understanding how they form and mature over time. Using histological stains and immunohistochemistry, we show that the walls of the mouse arterial roots show a gradual transition, with smooth muscle cells (SMC) forming the bulk of wall at the most distal points of attachments of the valve leaflets, while being entirely fibrous at their base. Although the interleaflet triangles lie within the ventricular chambers, we show that they are histologically indistinguishable from the arterial sinus walls until the end of gestation. Differences become apparent after birth, and are only completed by postnatal day 21. Using Cre‐lox‐based lineage tracing technology to label progenitor populations, we show that the SMC and fibrous tissue within the walls of the mature arterial roots share a common origin from the second heart field (SHF) and exclude trans‐differentiation of myocardium as a source for the interleaflet triangle fibrous tissues. Moreover, we show that the attachment points of the leaflets to the walls, like the leaflets themselves, are derived from the outflow cushions, having contributions from both SHF‐derived endothelial cells and neural crest cells. Our data thus show that the arterial roots in the mouse heart are similar to the features described in the human heart. They provide a framework for understanding complex lesions and diseases affecting the aortic root.     

Laboratory evaluation of enoxacin: comparison with norfloxacin and nalidixic acid

Enoxacin displayed activity similar to that of norfloxacin against enterobacteria, Pseudomonas aeruginosa, staphylococci, streptococci and Bacteroides spp. The activity of enoxacin against many strains was reduced in acid conditions, but the pH effect was not so marked as that seen with norfloxacin. Nalidixic acid was found to be more active in acid conditions, particularly against staphylococci, Streptococcus faecalis and Ps. aeruginosa. In conditions simulating the treatment of bacterial cystitis, a single dose of enoxacin, achieving a peak concentration of 50 mg/l, suppressed growth of nalidixic acid-sensitive and -resistant Gram-negative bacilli for periods of between 18 and 25 X 5 h. Reduced susceptibility of bacteria surviving exposure to enoxacin was observed in one nalidixic acid-resistant strain of Escherichia coli and in nalidixic acid-sensitive strains exposed to low doses (peak concentration = 5 mg/l) of enoxacin. These results are similar to those obtained with norfloxacin and substantially better than those obtained with nalidixic acid.     

Power spectral analysis of the effects of epinephrine,norepinephrine, dobutamine and dopexamine on microcirculation following free tissue transfer

Background: The use of pressor drugs after microsurgical free tissue transfer remains controversial because of potential vasoconstrictor effects on the free flap. Noninvasive monitoring of free flaps with laser Doppler flowmetry may provide further information regarding the local regulation of blood flow in the flap tissues during pressor infusions. This study evaluated the effects of four commonly used pressor agents. Methods: Twenty four patients (25 data sets) undergoing head and neck cancer resection and free flap reconstruction were recruited. Epinephrine, norepinephrine, dopexamine, and dobutamine were infused in a random order at four infusion rates, after surgery, with free flap and control area (deltoid region) laser Doppler skin blood flow monitoring. Frequency analysis of the Doppler waveform was performed utilizing the time period immediately before the first drug infusion for each patient as baseline. Results: At baseline there was less power at the 0.002–0.6 Hz frequency in the flap compared with control tissue consistent with surgical denervation. At maximum epinephrine infusion rates, the control of blood flow moved toward (i.e., proportion of power increased in) the lower frequencies, as smooth muscle mediated (myogenic) control began to dominate blood flow, an effect most marked with norepinephrine. Dobutamine and dopexamine had little effect on control of blood flow. Conclusions: Denervation of free flap tissue is demonstrable using spectral analysis of laser Doppler blood flow signals. With norepinephrine the control of blood flow shifts toward low frequency vasomotion where blood flow depends mostly on average blood pressure, making it potentially the most suitable agent following free tissue transfer. © 2013 Wiley Periodicals, Inc. Microsurgery, 2013.