Faculty Bibliography

Although the inotropic and dromotropic effects of cardiac glycosides in atrial fibrillation (AF) are well recognized, their action on AF itself is not clear. Accordingly, to determine whether cardiac glycosides prolong AF, the duration of electrically induced AF, atrioventricular conduction, and left ventricular function were assessed for 30 minutes before and for 30 minutes following intravenous administration of acetyl strophanthidin (AS), 20 micrograms/kg, in neurally intact, beta-blocked, and beta-blocked and vagotomized dogs. In the intact dog, AS, 20 micrograms/kg, increased peak dp/dt by 132 +/- 35 mmHg.sec-1, p less than 0.05, and slowed ventricular response by 16 +/- 7 min-1, p less than 0.05, but had a variable effect on AF duration. While the increased left ventricular peak dp/dt persisted for 15 minutes after AS, an increased duration of AF was evident only at 20 minutes, when the effects of AS on left ventricular (LV) inotropy were no longer apparent. Moreover, the subset of dogs that did not demonstrate prolongation of average duration of AF after AS had a greater increment of peak dp/dt than those that showed prolongation, 237 +/- 52 versus 53 +/- 31 mmHg.sec-1, p less than 0.05. An additional 20 micrograms/kg, which produced ventricular extrasystoles, prolonged AF duration when compared to both control and 30-minute measurements. Acetyl strophanthidin, 20 micrograms/kg, had a variable effect on duration of AF with beta-blockade but prolonged duration by 114 +/- 34%, p less than 0.05, with both vagotomy and beta-blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuronal migrational disorders of the brain represent abnormalities in the formation of the neocortex caused by faulty migration of the subependymal neuroblasts. These migrational anomalies include lissencephaly (agyria/pachygyria), pachygyria, schizencephaly, heterotopias, hemimegalencephaly, and polymicrogyria. We used MR imaging (performed on a 0.5-T or 1.5-T scanner) to evaluate 21 patients who had neuronal migratory anomalies. Four patients had lissencephaly, seven had pachygyria, including one patient with hemimegalencephaly, seven had schizencephaly, and three had heterotopias. All MR scans included T1-weighted spin-echo sequences, and seven also had inversion-recovery sequences. The cortical surface, cortex, and gray-white matter interface were well evaluated with both sequences; however, the inversion-recovery images were superior. All but two patients were imaged in both the axial and coronal planes: both projections demonstrated well the migrational abnormalities. MR is an excellent method for diagnosing the migrational anomalies of lissencephaly, pachygyria, schizencephaly, heterotopias, and hemimegalencephaly; it appears to be the imaging method of choice for evaluating these disorders

To assess the cardiovascular actions of magnesium in neurally intact animals, magnesium chloride (1-4 mM/min) administered i.v., producing a peak arterial magnesium level between 4.7 and 7.2 mg/dl, was given to alpha-chloralose-anesthetized, open-chest dogs. Magnesium lowered heart rate by 36 +/- 11 beats/min (P less than .05), cardiac output by 0.7 +/- 0.2 liters/min (P less than .05), left ventricular (LV) peak dP/dt by 410 +/- 96 mm Hg/sec (P less than .05) and aortic and pulmonary artery pressures, but it did not change LV end-diastolic pressure, systemic resistance or pulmonary resistance. Coronary blood flow also decreased by 39 +/- 11% (P less than .05), myocardial oxygen consumption by 88 +/- 22% (P less than .05) and myocardial oxygen extraction by 53 +/- 16% (P less than .05). When heart rate was held constant, magnesium still decreased LV systolic pressure, LV peak dP/dt and coronary blood flow. The increase in serum magnesium was accompanied by an increase in serum calcium (by 1.4 +/- 0.2 mg/dl; P less than .05) and a fall in serum potassium (by 0.21 +/- 0.1 mEq/l), but not by a change in serum sodium, myocardial electrolyte arteriovenous differences or arterial pH. Thus, at blood concentrations that are observed in humans after therapeutic dosages of magnesium, a depression of cardiac performance is observed in the anesthetized dog. Although magnesium produces a fall in coronary blood flow, this appears to be due at least in part to a decrease in myocardial oxygen requirements because myocardial oxygen extraction also decreases. Rapid changes in serum electrolytes accompany these hemodynamic effects.

PIP: The association between the nonverbal communication skills of physicians and patient satisfaction with medical care was assessed in 2 studies involving 71 residents in internal medicine and 462 patients. Scores on standardized, reliable, and valid measures of nonverbal skills such as the ability to communicate and to understand facial expressions, body movement, and voice tone cues to emotion were correlated with the ratings physicians received from patients regarding satisfaction with the technical and socioemotional aspects of the medical care received. Although physicians' nonverbal communication skills were little related to patients' ratings of the technical qualities of care received, measures of these skills did predict satisfaction with 'art of care' aspects. Specifically, the art of care assessment was dependent on the physicians' skill at understanding bodily nonverbal communication, the physicians' capacity to express emotion through voice tone, and their ability to avoid communicating negative emotion when intending positive. These findings provide support to the centrality of interpersonal effectiveness to the physician-patient relationship, especially nonverbal sensitivity and expressiveness. Improvements in the level of physicians' nonverbal encoding and decoding skills through training and selection can be expected to improve the quality of medical care and perhaps even its cost-effectiveness

Optic disc colloid bodies are more common than previously supposed. They were noted to occur in 2.04% of unselected globes obtained at autopsy. Hemorrhages of the disc and juxtapapillary fundus are not infrequently found in association with disc colloid bodies. Superficial hemorrhages may be due to erosion of existing disc blood vessels by enlarging colloid bodies, on the other hand, juxtapapillary hemorrhages may occur from neovascularization induced by the colloid bodies. Ultrasound examination may be useful as an aid in diagnosing disc colloid bodies.