Simulation and its role in medical education

Medical education is increasingly laying emphasis on a curriculum based on cognitive, psychomotor, and affective domains of learning which were originally proposed nearly 50 years ago. These reforms are framed around best standards of care, error management and patient safety, patient autonomy, and resource allocation. There is a worldwide shift in the method of medical education towards experiential (‘hands-on’) medical learning; however, applying this concept to real patients is less acceptable to society and is subject to legal and ethical issues.     

Factor V activity of platelets: evidence for an activated factor V molecule and for a platelet activator

This study was prompted by the observation that fresh platelet suspensions--prepared by gel filtration or albumin density gradient centrifugation--possessed only minimal factor V activity, whereas frozen-and-thawed platelet suspensions possessed striking factor V activity. Results of experiments with fresh suspensions suggested that unaltered platelets did not bind plasma factor V. The factor V activity of frozen-and-thawed platelet suspensions was markedly diminished after exposure to a factor V antibody, was not activated by thrombin, and was not associated with an increase in factor V antigen over that found in fresh platelet suspensions. Consequently, disruption by freezing and thawing must have resulted in the appearance of small amounts of an activated factor V molecule in platelet suspensions. Disrupted platelets were shown to activate native factor V, but an interaction between a platelet activator and traces of native factor V in fresh suspensions could not be demonstrated to account for the full activity of frozen-and-thawed suspensions. Apparently, therefore, platelets also contained an activated factor V molecule. Adding collagen, but not adenosine 5'-diphosphate to fresh platelet suspensions increased their factor V activity. Release of an activated platelet factor V molecule after exposure to collagen could represent a physiologically significant early step in hemostasis.     

Bone marrow in children with acute lymphocytic leukemia: MR relaxation times

Magnetic resonance imaging of the lumbar spine was performed in 17 children with acute lymphocytic leukemia (ALL): eight with newly diagnosed ALL, four with ALL in relapse, and five with ALL in remission. Eleven age-matched children were also imaged as controls. The T1 and T2 relaxation times of the bone marrow in the lumbar spine were calculated for all the children. The T1 relaxation times of the bone marrow were as follows (mean +/- standard deviation): newly diagnosed ALL, 968 msec +/- 68; ALL in relapse, 765 msec +/- 19; ALL in remission, 404 msec +/- 135; and age-matched controls, 441 msec +/- 82. T1 relaxation time was statistically significant in differentiating children with newly diagnosed ALL from normal children and from children with ALL in remission. In addition, T1 may be useful in differentiating children with ALL in relapse from children with ALL in remission and from healthy children. T2 was not significantly different among the four groups.     

Abnormal gastro-oesophageal reflux in Chinese with atypical chest pain

Although atypical chest pain has been well described in the Western population, its frequency in Chinese is unknown. Over a period of 42 months, we studied 521 Chinese patients with chest pain and identified 108 patients (20.7%) whose pain was not related to cardiac causes, as determined by exercise ECG or cardiac catheterization. Using 24 h ambulatory pH monitoring and baseline oesophageal manometry, 28.7, 19.4 and 5.6% of these patients were found to have abnormal reflux parameters, abnormal manometric findings or both, respectively. There were significantly more patients complaining of chest pain during the study in the gastro-oesophageal reflux disease (GERD) group than in the non-GERD group (16/31 vs 20/77; P< 0.001). The lower oesophageal sphincter pressure was lower in those with abnormal reflex parameters than in those with normal reflux parameters (12.7±5.4 vs 17.8±5.8 mmHg; P< 0.05). There was no significant difference in symptoms, such as heartburn (54.8 vs 42.9%), regurgitation (38.7 vs 35.1%) and dysphagia (19.4 vs 24.7%), among the two groups. Non-specific changes were the most frequent baseline motility pattern. In conclusion, atypical chest pain and gastro-oesophageal reflux disease are not uncommon in Chinese and this deserves special emphasis as the continuation of anti-anginal drugs may aggravate their condition.     

A routine method for the simultaneous measurement of retinol, α-tocopherol and five carotenoids in human plasma by reverse phase HPLC

We describe a simple isocratic HPLC method for the accurate and precise measurement of retinol, α-tocopherol and the major carotenoids in plasma using UV detection. Reference ranges for retinol, α-tocopherol and five carotenoids are determined in a healthy population group. The most abundant carotenoids found in plasma were β-carotene, lycopene, lutein and cryptoxanthin. Retinol, α-tocopherol and carotenoids were determined simultaneously using two internal standards, retinol acetate for retinol and tocopherol acetate for α-tocopherol and carotenoids. The use of echinenone as an internal standard for carotenoids was investigated. The protective effect of an antioxidant (ascorbic acid) on the stability of samples and extracted material is documented. The method is useful for the routine measurement of plasma retinol, α-tocopherol and carotenoids and could also be used in large scale epidemiological studies.     

Duplication of 16q and deletion of 15q

A patient with distal arthrogryposis, congenital dislocations of the hips, a prominent forehead, epicanthal folds, thin lips, and a poorly defined philtrum was found to have a deletion of 15q and a duplication of 16q. Her mother, maternal grandmother, and great grandmother had a balanced t(15q-, 16q+). The gene for adenine phosphoribosyl transferase was assignable to the 16q22----16qter area that was duplicated.