A learning resources centre: its utilization by medical students.

Innovations in medical education have led to the increasing use of problem-based learning techniques, a committee system organization, and more time for independent study in many undergraduate programmes. There has been an increase in availability of alternative methods for presentation of information. To encourage self-directed learning, resources such as computers, videos and models, among others, should be readily available to students. The University of Calgary Faculty of Medicine has provided various resources contained in one area, called the Bacs Learning Resource Centre (BLRC). Since the maintenance and further development of such a centre requires significant resources, it is important to determine student utilization of the various components used in their learning. For those who are about to set up such a learning resource centre this information gives guidance on which materials are most useful. The utilization of the centre by 69 first year medical students was studied using questionnaires. The utilization during a specific course was determined by analysing the entries in the individual log books given to the students at the beginning of the Integrative Course. With the exception of one student, all those who responded to the questionnaire used the Centre, with 20% or less of their total study time being spent there. The BLRC was most used for the Musculoskeletal, Cardiovascular and Reticulo-Endothelial courses. All categories of resources were found to be useful, with the tape/slides least utilized. Utilization was most influenced by the quality of resources available and recommendations by peers. The development of a centre such as the BLRC, with a variety of resources concentrated in one area, suitable for individual or group study and accessible 24 hours a day, should be considered by all medical schools to enhance self-directed learning in medical students.

Guidelines for estimating the real cost of an objective structured clinical examination.

A major impediment to the use of the objective structured clinical examination (OSCE) is that it is a labor-intensive and costly form of assessment. The cost of an OSCE is highly dependent on the particular model used, the extent to which hidden costs are reported, and the purpose of the examination. The authors detail hypothetical costs of running a four-hour OSCE for 120 medical students at one medical school. Costs are reported for four phases of this process: development, production, administration, and post-examination reporting and analysis. Costs are reported at two ends of the spectrum: the high end, where it is assumed that little is paid for by the institution and that faculty receive honoraria for work put into the examination; and the low end, where it is assumed that the sponsoring institution defrays basic costs and that faculty do not receive honoraria for their participation. The total costs reported for a first-time examination were $104,400 and $59,460 (Canadian dollars) at the high and low ends, respectively. These translate to per-student costs of $870 and $496. The cost of running an OSCE is high. However, the OSCE is uniquely capable of assessing many fundamental clinical skills that are presently not being assessed in a rigorous way in most medical schools.

Medical school M.D. graduates' activities in research and teaching (Alberta medical schools--1973-85).

The paucity of clinicians entering research and teaching careers has been noted. This study examines the proportion of M.D. graduates from Alberta medical schools (with different selection and educational philosophies) who have chosen such careers, and discusses when the graduates' major research interests developed and the significance of the findings to future manpower requirements.

Changes in left ventricular dimensions and performance resulting from acute and chronic volume overload in the conscious dog.

A previously described animal model with an aorta to left atrium shunt has been modified to assess changes in left ventricular dimensions and performance resulting from volume overload of the left ventricle and to determine if any of these changes can predict outcome. In eight surviving dogs, end-diastolic and end-systolic diameters and estimated stroke volume increased rapidly in a curvilinear fashion over approximately 60 days with no significant changes thereafter. Mean normalized circumferential fibre shortening velocity was slightly less than and fractional shortening was similar to the controls; the changes in both indices were parallel to those in the controls. In five dogs that died 5-18 days postoperatively in congestive heart failure, none of the measurements obtained could be used to predict the outcome; the changes in the left ventricular diameters were similar to those in the survivors and systolic function was either normal or enhanced.

The effects of changes in inspired oxygen concentration on the experimental production of pulmonary edema in the dog with chronic left ventricular overload.

A twofold increase in left ventricular output was achieved by suturing a Telfon graft between the aorta and left atrium in dogs. Three weeks after surgery the animals were anesthetized and found to have left ventricular end-diastolic pressures averaging 36 mmHg with markedly elevated right ventricular systolic pressures (RVSP). Oxygen breathing resulted in a decrease in left ventricular pressures, RVSP, and arterial pressure in those animals which survived hypoxia. Fifty percent of the shunted dogs subsequently developed fatal pulmonary edema when allowed to breathe 10% oxygen in nitrogen. These animals showed no change in left ventricular function or pulmonary artery pressure (RVSP) in response to pure oxygen administration. It is suggested that there is a gradation of hemodynamic response to pure oxygen depending on the severity of left ventricular overload. In the severest case the 'fixing' of pulmonary hypertension may be due to neurohumoral mechanisms. The subsequent development of pulmonary edema in these animals with hypoxia either involves a change in permeability or a redistribution of hydrostatic pressure within the pulmonary vasculature.

Mechanisms regulating the renal excretion of sodium during pregnancy.

Observations were made on the relation of the renin-angiotensin-aldosterone system and renal hemodynamic function to sodium balance in 43 pregnant dogs. Daily balance studies revealed that about 30-40% of ingested sodium was retained during the last half of pregnancy; during the same period, potassium balance was also positive but to a lesser extent. For groups of pregnant dogs, plasma renin activity (n = 14) and aldosterone secretion (n = 19) were significantly higher than normal; however, in some animals one or both functions were normal even though sodium retention was present. In contrast, plasma renin substrate concentration was consistently elevated during pregnancy in seven dogs. In a group of nine dogs in which both aldosterone secretion and plasma renin activity were measured, aldosterone secretion was elevated in the three dogs with the highest values for plasma renin activity; in two of the remaining six animals aldosterone secretion was elevated but plasma renin activity was normal or only slightly increased. The sequestration of sodium and water into the uterine contents was defined quantitatively in this study but evidence was lacking to support the idea that such changes led to renin release. The glomerular filtration rate (GFR) was significantly elevated throughout pregnancy but a significant decrease from the high level of mid-pregnancy occurred during the last half of pregnancy; this decrease in GFR probably contributed to the sodium retention. Administration of a large dose of deoxycorticosterone acetate (DOCA) to dogs in late pregnancy produced marked sodium retention but "escape" from the sodium-retaining steroid occurred. The data demonstrate that although increased activity of the renin-angiotensin-aldosterone system was frequently present during pregnancy, a normal rate of aldosterone secretion occurred. This finding and the observed "escape" from DOCA suggest the existence of sodium-retaining mechanisms other than the mechanism provided by a high plasma level of aldosterone.