Biomedical subjects
G Whelan
Publications and source records attributed to G Whelan.
Biological markers of alcoholism.
The roles of two categories of biological markers--those relating to alcohol consumption and those relating to the risk of developing alcohol related problems--are reviewed. Platelet Mono-amino oxidase levels are low in individuals with a strong inheritance of their drinking problem (Cloninger Type II alcoholics). Elevated gamma-glutamyl transpeptidase (GGT) levels identify regular heavy drinkers with a sensitivity between 40-60%. Mean corpuscular volume (MCV) has a high specificity (95%) and is useful in detecting regular heavy drinkers in the ambulatory care population if other causes of an elevated MCV can be included.
Oesophageal propulsive force and its relation to manometric pressure.
A fixed volume capsule incorporating a force transducer and a side hole for manometric measurements was constructed and calibrated. Simultaneous measurements of the propulsive (aboral) force and the manometric pressure (intraluminal pressure) were made at 5, 10, and 15 cm above the lower oesophageal sphincter and in response to dry and wet (5, 10, and 15 ml) swallows. The propulsive force and manometric pressure waves had a simultaneous onset and were of similar duration. Peak values of propulsive force for wet swallows increased significantly as measurements were made progressively more distally within the oesophagus and were greatest in the distal oesophagus. The association between manometric pressure and propulsive force is not strong (r = 0.61) suggesting that intraluminal pressure is a poor predictor of propulsive force and hence an unreliable measure of oesophageal 'function'.
The assessment of depth of anaesthesia in animals and man.
The assessment of the depth of anaesthesia in man has received much attention in recent years, following a number of reports of people being aware during surgery. A range of different measures have been suggested for determining the adequacy of anaesthesia in man, but such a critical assessment is rarely applied to laboratory animals. This article describes the methods used to assess anaesthetic depth in both man and animals, and compares the relative states of knowledge about anaesthetic depth in animals and man.
Does a blood alcohol level of 0.15 or more identify accurately problem drinkers in a drink-driver population?
OBJECTIVE: To determine whether a blood alcohol concentration (BAC) of 0.15 or more identifies accurately problem drinking in an apprehended drinking driver. DESIGN: Cross-sectional analytic study of 86 drink drivers ("diagnostic test study"). SETTING: St Vincent's Hospital, Melbourne, drink-driver education programme. SUBJECTS: Men aged between 18-25 years, applying for relicensing after disqualification, who were participants at 10 consecutive drink-driver education courses conducted in early 1987. OUTCOME MEASURES: Self-reports of the amount of alcohol consumed and the amount of money spent on alcohol per week, the standard Michigan Alcoholism Screening Test (MAST) score and the blood alcohol level at apprehension. The first three measures were used as reference standards for alcohol-related problems, against which the blood alcohol level was compared. MAJOR RESULTS: Scatter plots of BAC against amount consumed, amount spent and the MAST scores showed that a large proportion of the heaviest drinkers were not identified by the BAC. Log-transformed correlation coefficients were: for amount spent v. amount consumed, r = 0.73; for MAST score v. amount consumed, r = 0.52, and for MAST score v. amount spent r = 0.53. Correlating the BAC with the log of the MAST score gave r = 0.21, BAC with log of the amount consumed, r = 0.20, and BAC with log of the amount spent, r = 0.15. Comparing a BAC of 0.15 or more with a MAST score of greater than or equal to 5, we obtained a sensitivity of 0.36, a specificity of 0.76, a positive predictive value of 0.86, and a negative predictive value of 0.23. The prevalence of heavy drinking as measured by the MAST score was 0.80. CONCLUSION: A blood alcohol concentration of 0.15 or more identifies only a third of the problem drinkers in this sample of drink drivers. Although it selected a group of drinkers with alcohol-related problems, it missed most of the problem drinkers and did not reliably identify the heaviest drinkers.
Principles behind practice. Using the diagnostic test.
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Prevalence of columnar-lined (Barrett's) esophagus.
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Ulcerative colitis--what is the risk of developing colorectal cancer?
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Is antenatal screening for syphilis worth while?
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Epidemiology of inflammatory bowel disease.
Epidemiologic studies of inflammatory bowel disease indicate that these disorders occur in susceptible individuals, possibly due to genetic abnormalities, resulting in disturbance of bowel wall function. Environmental factor(s) exerting a primary effect at an early age, in most patients, cause the disease to manifest usually in teenagers or young adults. Secondary environmental factors may alter disease expression, severity, or influence relapse. Studies in identical twins provide the best evidence for the role of genetic factors in the cause of Crohn's disease. Changing trends in disease incidence (seen in many countries) provide strong support for environmental factors as playing a major influence in disease expression. We now require further laboratory and epidemiologic studies in family members at risk of disease, in migrants who move from low incidence areas to high incidence areas, and in area where Crohn's disease particularly is starting to appear. The clinician can play an important role by performing careful observations in patients with a view to uncovering new clues to disease etiology.
The approaches to learning of specialist physicians.
Recent studies have provided information about the approaches to studying and learning used by medical students. However, no published work is available on the approaches of practising doctors. The Adelaide Diagnostic Learning Inventory for Medical Students (ADLIMS) was modified and administered to a random sample of 308 physicians (internists). Generally speaking, physicians seem to have lower scores on surface approach and higher scores on deep approach than students. Level of clinical experience did not appear to influence this finding. However, marked differences were apparent between the approaches adopted by physicians with additional postgraduate academic training and those without. The former had a much stronger tendency to use the more desirable deep approach. The latter seemed to rely more on the less desirable surface approach. Further longitudinal studies will be required to determine whether this difference is attributable to self-selection of those who have already developed a deep approach or is causally related to a training in research. Although these findings must be interpreted with caution, some implications are clear. Physicians should become more aware of the way they learn and about the way they teach. Inappropriate patterns of learning may be entrenched during the undergraduate and immediate postgraduate years. If validated, these findings may provide support for the inclusion of research projects in medical school and during specialist training.
Physicians' approaches to continuing education.
A questionnaire survey was conducted of a random sample of 308 physicians to determine their actual and preferred approach to continuing education. Demographic data raised questions about the possible influence of the undergraduate institution attended, the future impact of the growing proportion of women physicians and the effect of increasing subspecialisation. The average physician spends eight-nine hours a week on educational activities and 2.5-4.0 hours a week teaching. Unstructured ad hoc reading and postgraduate activities predominate over methods based on specific, individual needs or on current patient problems. The educational desirability of this is questioned. Physicians are avid attenders at conferences with 10-15% being at a national or international meeting in any one survey week. It appears physicians would prefer to use a wider range of educational activities including more refresher courses and innovative methods. By comparison, Canadian physicians showed similar, but more strongly evident, preferences. These findings have important implications for the College. It appears physicians need to be better informed about potentially more effective learning methods and account ought to be taken of their preference for methods which are not currently widely available.
Some phenomena of medical students' diagnostic problem-solving.
This paper introduces a perspective on medical problem-solving that derives from recent studies of content-related learning. Results from a study of fourth-year medical students' approaches to understanding a data base of significant facts about a patient (a problem synthesis) are presented. By analysing data collected in interviews, we obtain categories of description that portray the qualitatively different ways in which the information in diagnostic problems is handled by these students. Two major categories describe the variability in approach: 'ordering' and 'structuring'. The latter category contains elements that most clinical teachers would regard as desirable; the former represents a less satisfactory approach. We provisionally identify two diagnostic strategies within each of these categories. The perspective has implications for improving instruction and assessment.
Towards the identification of student learning problems: the development of a diagnostic inventory.
An understanding of how students approach their learning has important implications for medical education. Of particular interest is the fact that the approach students use in their study has a significant impact on both the quality of the learning and their academic success. It would clearly be of value to identify students whose approach to learning was predictive of unsatisfactory performance. This paper describes the initial development of two versions of an inventory (questionnaire) which was designed to aid in the diagnosis of student learning problems. Preliminary information is given on the reliability and validity of these instruments. Factor analyses support the underlying design. Correlation of subscales with academic performance has provided encouraging evidence of the potential of these inventories in identifying students with specific learning or study problems.
Relative incidence of Crohn's disease and ulcerative colitis in six Melbourne hospitals.
Information on the relative incidence of Crohn's disease and ulcerative colitis was obtained by a prospective investigation at six Melbourne teaching hospitals. One hundred and eleven patients who presented with chronic inflammatory bowel diseases between 1980-1981 were admitted to the study. Forty (36%) patients were diagnosed as having Crohn's disease and 63 (57%) patients as having ulcerative colitis. The type of chronic inflammatory bowel disease could not be determined in eight (7%) patients. These findings suggest that the relative frequency of Crohn's disease and ulcerative colitis in Melbourne hospitals is within the range that is reported for northern Europe and the United States.
Oesophageal manometry: how well does it predict oesophageal function.
The variability in manometric measurements of oesophageal peristalsis was assessed in 10 volunteers. The amplitude, velocity and duration of the peristaltic waves resulting from 10 separate 10 ml boluses of water were measured at fixed distances above the lower oesophageal sphincter (LOS). After a 10 minute rest period with the manometry catheter still in situ peristaltic values in response to a second group of 10 10 ml boluses were measured. The measurement of peristaltic amplitude at a fixed distance above the LOS showed wide interindividual variation--for example, at 8 cm above the LOS the variation between individuals was marked (p less than 0.001). At the same site, however, there was only a small intra individual variation noted with time (p greater than 0.25). Similar differences were noted at 16 and 4 cm above the LOS. For the first group of swallows, while the interindividual variation remained high (p less than 0.025), the measurement variation from site to site was of lesser magnitude (p greater than 0.1). Similar findings were noted for interindividual variation and site to site variation at the second group of swallows. The values for velocity showed a similar pattern of variation. From this study we conclude that manometric measurements can be used as a valid method for assessing the effects of drugs on peristalsis in individuals provided all measurements are made at the exact same level in the oesophagus and 'normal' subjects with a large inherent variation are excluded. Any studies comparing peristaltic values in different population groups - for example, normal v reflux patients, may not detect any significant difference even with large sample numbers. Any differences detected may be of no clinical importance because of the large normal variation.
Hepatic vein occlusion (Budd-Chiari syndrome): problems in diagnosis and management.
Seven patients demonstrating the difficulties in diagnosis and management of hepatic vein occlusion are presented. The syndrome may present in an acute form with upper abdominal pain, abdominal swelling, ascites and tender hepatomegaly or in a chronic form, mimicking cirrhotic ascites. The clinical features, predisposing factors, liver scan and liver biopsy may all suggest the condition, but hepatic venography is essential for diagnosis and as a preliminary to treatment. It is suggested that early side to side portacaval anastomosis is the current treatment of choice.
Prevalence of hepatitis B in a general hospital: screening of patients and staff.
Hepatitis B surface antigen (HBsAg) was sought over a six-month period in patients and staff members of the intensive care, cardiothoracic, and haematology/oncology units of a large general hospital. In addition, HBsAg was sought in all inpatients, outpatients and staff members at one point in time during August, 1977. A positive HBsAg state occurred with a prevalence of 1.55% in the three intensively studied units (cardiothoracic unit, 0.88%; haematology/oncology unit, 1.65%; and intensive care unit, 3.1%) and 0.9% for the point prevalence survey of hospital patients excluding the three intensively monitored areas. Very few of these patients had disorders traditionally associated with hepatitis B antigenaemia. In the survey of staff members, 0.72% of results were HBsAg positive. Of the factors examined, the most important determinant of the hepatitis B positive state both in patients and in staff members was their country of origin (that is, being born in southern or eastern Europe or in Asia).