Features of cardiac disease demonstrated on CT pulmonary angiography.

The heart and mediastinal structures can be overlooked at CT pulmonary angiogram (CTPA). This pictorial review will demonstrate the features of cardiac disease that may be evident on a CTPA. CTPA allows assessment of not only the pulmonary arteries for embolism, but also of the bronchi, lung parenchyma, mediastinum and heart. Co-existent underlying or incidental cardiac disease is often present. Potentially life-threatening alternative diagnoses in a patient with chest symptoms can be reliably identified. Pathologies of the myocardium including hypertrophic cardio myopathy, pericardial disease, valvular disease, coronary artery disease, and intracardiac abnormalities are demonstrated pictorially. CTPA is increasingly used for the detection of pulmonary embolism. Most patients investigated have pathology other than PE as a cause of their symptoms. Frequently information about the heart is produced that provides important clues to determine the cause for the presenting symptoms and signs or reveals co-existing pathology. It is important to have a clear understanding of the features of cardiac disease which may be seen on a CTPA.

Glucocorticoid replacement is permissive for rapid eye movement sleep and sleep consolidation in patients with adrenal insufficiency.

There is a well described temporal relation between hormonal secretion and sleep phase, with hormones of the hypothalamic-pituitary-adrenal (HPA) axis possibly playing a role in determining entry into and duration of different sleep stages. In this study sleep features were studied in primary Addison's patients with undetectable levels of cortisol treated in a double blind, randomized, cross-over fashion with either hydrocortisone or placebo supplementation. We found that REM latency was significantly decreased in Addison's patients when receiving hydrocortisone at bedtime, whereas REM sleep time was increased. There was a trend toward an increase in the percentage of time in REM sleep and the number of REM sleep episodes. Waking time after sleep onset was increased, whereas no differences were observed between the two conditions when total sleep time or specific non-REM sleep parameters were evaluated. Our results suggest that in Addison's patients, cortisol plays a positive, permissive role in REM sleep regulation and may help to consolidate sleep. These effects may be mediated either directly by the central effects of glucocorticoids and/or indirectly through CRH and/or ACTH.

How many visits by health professionals are needed to make a difference in low birthweight? A dose-response study of the Toronto Healthiest Babies Possible program.

The association of risk factors such as smoking, nutrition and adolescence with low birthweight has been well documented. What is less known is the extent to which certain program interventions can mediate the impact of these risks on low birthweight and the level of intervention necessary to have an impact. This study had two objectives: (a) to explore the role of the Toronto Healthiest Babies Possible (HBP) program as a mediator of the impact of smoking, adolescence, prepregnancy underweight and erratic weight gain/initial weight loss on LBW, and (b) to determine the dose-response relationship between the number of home visits and LBW. Study results suggest that the HBP strategy is making a difference for clients with the aforementioned three risk factors, and that the most effective intervention "dose" to reduce low birthweight is 9-11 visits. This type of study may serve as a benchmark in the evaluation of other similar programs.

Echocardiography in district general hospitals: trends over a five-year period 1993-1998.

Postal surveys were carried out in 1993 and 1998 to establish the range and nature of echocardiography facilities within district general hospitals in Scotland. This study examines some of the changes over this five year period. Echocardiography services vary widely between hospitals. There have been substantial changes in the last five years, with increases in both the staff involved in echocardiography and in the number of investigations performed. The facilities available have improved and more respondents to the survey in 1998 were happy with training than in 1993. Echocardiography has a major place in modern management of patients with cardiac problems. This survey provides a useful benchmark for comparison between services.

"Directoring" and managing in a professional system.

Pathologists are under siege by corporate medicine, managed care systems, or varieties of government-initiated health care restructuring. The pressure is on us to attend at least equally to fiscal pressures, as well as to our patients' medical needs. These pressures must be accommodated within the limits of our professional duties and responsibilities. We must have more than an intuitive sense of what it is to be a professional and to work in a system that is overseen typically by a directorate and that includes managers and innovators. The example of the failure of the corporate managers and directors of a national blood transfusion service highlights the need to balance the inter-relationships of managers, professionals, and innovators by a directorate knowledgeable in these complex systems.

Directing change: a contemporary administrative challenge.

Although most individuals who head clinical laboratories are still named Director of Laboratories, their training for this has focused principally on management training in addition to their postgraduate medical education. The implicit assumption seems to be either that direction and management are synonymous or that management is the most important aspect of laboratory administration. Common usage, albeit imprecise, fosters both of these paradigms. The proposition of this article is that directing and managing are two discrete activities of sufficiently different orientation as to require different training, attitudes, and values. Management as a generic phenomenon was codified early in this century through the works of F.W. Taylor (1), whose concepts of scientific management were embraced with zeal during World War I and were also an important conceptual basis for the managed economy of the Soviet Union as proposed by Lenin. Gradually, management with concern for efficiency and hierarchic control structures has diffused throughout social as well as business systems. Many will remember the introduction of the corporate governance system into hospitals beginning in the 1930s and its spread throughout the medical system until at present administrators of hospitals, for example, are called CEOs or presidents. Management, as narrowly defined and as traditionally practiced, is based on control of a system by adherence to prescribed standards for uniform production, to particularized timelines for delivery of product or service precisely when needed, and to predetermined budgets for efficiency and predictability. All of these are laudable and essential to the internal administration of any system. They also require a specific set of values and a set of behaviors that center on adaptability and compliance.

Decreased delta-sleep and plasma delta-sleep-inducing peptide in patients with Cushing syndrome.

To evaluate the sleep disturbances of patients with Cushing syndrome and to examine the relationship between the sleep disturbances and plasma levels of delta-sleep-inducing peptide-like immunoreactivity (DSIP-LI), we performed three polysomnographic/endocrinological studies in patients with Cushing syndrome. In study 1, polysomnography was studied in 12 patients and 12 matched normal volunteers. In addition, DSIP-LI was measured every 30 min for 24 h in 9 patients with Cushing syndrome and 12 normal volunteers. The percentage of time spent in delta sleep (stages 3 and 4) was significantly reduced in patients with Cushing syndrome (5.8 +/- 1.4%; mean +/- SEM) compared to normal volunteers (14.0 +/- 2.5%) (p < 0.01). REM sleep indices, however, were not significantly different between the two groups. There was a significant negative correlation between amount of delta sleep and 08.00 h DSIP-LI (r = -0.43, p < 0.05), which is against the notion of a causal relationship between DSIP-LI and delta sleep. The circadian rhythm of plasma DSIP-LI was found to be similar in Cushing patients and normal volunteers. In study 2, we measured plasma levels of delta-sleep-inducing peptide-like immunoreactivity (DSIP-LI) at 08.00 h in 65 patients with Cushing syndrome and 49 normal volunteers. The 08.00 h DSIP-LI concentrations of 797 +/- 57 pmol/l (mean +/- SEM) in the patients with Cushing syndrome were significantly reduced compared to the level of 1,062 +/- 99 pmol/l found in the normal volunteers (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Diurnal rhythm of plasma delta-sleep-inducing peptide in humans: evidence for positive correlation with body temperature and negative correlation with rapid eye movement and slow wave sleep.

Since delta-sleep-inducing peptide (DSIP) was isolated in 1977, numerous reports have suggested that this nonapeptide stimulates delta-sleep [slow wave sleep (SWS)]. Although DSIP-like immunoreactivity (DSIP-LI) has been found in the serum of many animals and man, its diurnal rhythm and relation to sleep stages have not been well defined. We hypothesized that circulating levels of this putative sleep hormone would be highest at night and would probably be elevated before or during episodes of SWS. We, therefore, measured plasma DSIP-LI levels every 30 min for 24 h in 12 normal volunteers in whom we obtained simultaneous polygraphic recordings. We found a distinct diurnal rhythm for plasma DSIP-LI levels, with the maximum at 1500 h and the minimum at 0100 h. DSIP-LI levels were substantially lower in rapid eye movement sleep (P < 0.005) and somewhat lower in SWS (P < 0.05) compared to awake values. DSIP-LI levels did not rise before, during, or after a significant percentage of episodes of SWS. We found, however, that the diurnal rhythm of DSIP-LI closely followed that of body temperature with a high degree of correlation (r2 = 0.66; P < 0.0001). We conclude that endogenous elevations of circulating DSIP may be associated with suppression of slow wave and rapid eye movement sleep, and that the circadian rhythm of this peptide is coupled directly or indirectly to that of body temperature.

Economic analysis of the clinical laboratory: labor implications.

Expenditures on laboratory tests have increased by 468% in real dollars in two decades although the cost per test has remained constant. Cost of labor has doubled over that period, with an approximately similar increase in personnel productivity as the offset. Part of the increased labor cost relates to increased pay for technologist work of apparent increased complexity. We found that technologists perceived less than 20% of all work and less than 4% of all tests performed to be highly complex or of moderately high complexity. Implications of these findings for test complexity analysis and for technologist training are discussed.

Aortic stenosis in elderly people: an evaluation of clinical and echocardiographic diagnosis.

In a prospective study to assess the sensitivity and specificity of clinical diagnosis against echocardiographic diagnosis in elderly people, 41 patients were studied in two 6-month periods. Overall clinical and echo diagnosis agreed in 75% of cases, but the clinical diagnosis of aortic stenosis was poor in the initial period. Adapting the lessons which were learnt in this initial period in a repeat of the study, the sensitivity of clinical diagnosis of aortic stenosis improved from 0.38 to 0.75. Additional information was gained in 50% of cases by echocardiography, and enabled the clinician to modify treatment in 50% of cases. Aortic stenosis in elderly people may be without clinical signs. Routine echocardiography increases the sensitivity of the clinical diagnosis, and may have major therapeutic implications for the elderly patient.

Clinical laboratory management: a critical evaluation.

The clinical laboratory is described as a system with an enquiry component or demand side, where control of test utilization is the mandate of the clinical physician or surgeon, and a production component or supply side, where answers to clinical questions are generated and control of test data production is the mandate of the laboratory physician. Supply side unit costs are maintained by increased production effectiveness brought about by the judicious manipulation of supply costs; labor costs; and capital expenditures for automated equipment, robots, and information technologies. The pathologist's prime role as controller of the supply side is outlined, as are the clinical physician's prime role and pathologist's subsidiary role in control of test use on the demand side.

Managing bedside glucose testing in the hospital.

The scope and magnitude of bedside testing by personnel without formal laboratory training have recently increased. There has been some question about the reliability of bedside test results produced by nurses, physicians, and other ward staff that are used in clinical decisions. Glucose testing is currently the most widely performed bedside test. Because of the likelihood that the use of bedside testing will increase in the future, this article discusses various issues concerning bedside glucose analysis, including the scope of such testing, staff responsibilities, training and supervision, testing frequency, work flow and result reporting, and the reliability of bedside glucose results, in three institutions. We also suggest an approach to bedside testing quality management.

Interactions of the alkyl-ether-phospholipid, platelet activating factor (PAF) with platelets, neural cells, and the psychotropic drugs triazolobenzodiazepines.

PAF-acether, a naturally occurring phospholipid, is a potent activator of various biological processes, including platelet aggregation. The mechanisms of action of PAF are largely unknown. We have found that the psychotropic triazolobenzodiazepine drugs, alprazolam and triazolam, potently (IC50 less than 1 microM) inhibit PAF-induced shape change, aggregation and secretion of human platelets. These effects are specific for PAF-activation, since the responses of human platelets to other agonists (ADP, thrombin, epinephrine, collagen, arachidonate and the Ca++ ionophore, A23187) are not inhibited by these triazolobenzodiazepines. The action of triazolobenzodiazepines on PAF-induced platelet function has clinical relevance, especially in diseases where enhanced platelet aggregability may lead to thrombosis and atherosclerosis. In addition, the ability of triazolobenzodiazepines to inhibit other PAF-mediated cellular-responses, such as anaphylactic shock or bronchoconstriction, suggests that these drugs may be useful in preventing several known pathophysiological effects of PAF. The specific antagonism of PAF action by psychotropic drugs also suggests that PAF or PAF-like phospholipids may play a role in neuronal function. This possibility was tested by examining the effects of PAF on neural cells of the clonal line NG108-15, grown in culture in a chemically defined, serum-free medium. Low concentrations of PAF (0.5-2.5 microM) induced neurite extension in NG108-15 cells, whereas higher concentrations (greater than 3 microM) were cytotoxic. Using NG108-15 cells preloaded with aequorin, it was found that PAF causes an increase in intracellular ionized calcium concentration, which is dependent on the presence of extracellular calcium. These results suggest that PAF-induced Ca++ uptake may play a role in neuronal development, and that circulating PAF may contribute to the neuronal degeneration caused by the exposure of neural tissues to blood in situations such as spinal cord injury, trauma, or stroke.