The v-erbA oncogene requires cooperation with tyrosine kinases to arrest erythroid differentiation induced by ligand-activated endogenous c-erbA and retinoic acid receptor.

The v-erbA oncogene, a mutated version of the thyroid hormone receptor alpha (c-erbA/TR-alpha), cooperates with tyrosine kinase oncogenes in erythroblast transformation. Here we show that the ligand-activated, endogenous retinoic acid receptor (RAR-alpha), in cooperation with c-erbA/TR-alpha, efficiently reverses the transforming effect of kinase oncogenes, overcoming oncogene-induced self-renewal by triggering terminal differentiation of the transformed cells into healthy erythrocytes. This differentiation induction was accompanied by up-regulation of erythrocyte gene expression. Similarly, RAR-alpha and over-expressed exogenous c-erbA/TR-alpha efficiently abolished the differentiation arrest caused by v-erbA, while the low levels of endogenous TR-alpha had no effect. In contrast, transformation by v-erbA plus a kinase oncogene was not affected at all by ligand-activated endogenous or over-expressed exogenous TR-alpha and RAR-alpha. These results suggest that oncogene cooperation is required to protect leukemic erythroblasts from differentiation induction via endogenous, nuclear hormone receptors. Endogenous c-erbA/TR-alpha and RAR-alpha apparently cooperated in abolishing erythroblast self-renewal and inducing differentiation, since the respective ligands acted in a synergistic fashion, and overexpressed, non-ligand-bound c-erbA/TR-alpha suppressed endogenous RAR-alpha function in differentiation induction. Genetic evidence is presented that this functional cooperation requires the receptor dimerization domain, suggesting that TR-alpha/RAR-alpha heterodimers play a role in regulation of erythroid differentiation.     

Eight year study of viral isolates from cot deaths in Glasgow

Over an eight year period 21 different viral strains excluding polioviruses were isolated in 44 (19%) of 237 cot deaths. The percentage of viral positive cases was significantly greater in over 16 week age groups and in cultures obtained less than 24 hours after death.     

Neuromuscular disease, respiratory failure and cor pulmonale.

Respiratory muscle weakness is an uncommon cause of chronic respiratory failure and a rare cause of cor pulmonale. The problem may not be apparent unless specific physical signs are sought or appropriate investigations performed. We present three patients who presented diagnostic difficulty for prolonged periods until the presence of respiratory muscle weakness was considered. Once the diagnosis was established treatment with nocturnal nasal intermittent positive pressure ventilation produced a dramatic improvement in symptoms and allowed a return to a near normal lifestyle.     

Development and implementation of an innovative intern training programme

The quality of medical education during internship is a cause for concern. This paper describes a structured educational programme for interns that was based around learning modules, clinical attachments and bedside teaching. The programme was incorporated into the term rotation of interns within an Area Health Service, and evaluated. Learning modules were timetabled by a Programme Coordinator and interns were reminded to attend. Clinical attachments were organized by the interns from a list of willing supervisors. Attendance at timetabled learning modules averaged 67%, which was greater than the 27% attendance at clinical attachments. Both sessions received high ratings for quality and clinical relevance. This structured education programme was based upon adult learning methods and was both feasible and well received by interns. Intern training programmes need to be programmed into the working week to ensure attendance, and modified following evaluation by interns. Such programmes should be considered by all hospitals to which interns are allocated.     

Antenatal Screening for HPA-la by Flow Cytometry

Summary: regnant women who attended antenatal clinics at King George V Hospital, the Birth Centre or were referred by obstetricians from February to July. 1996 were screened for the platelet antigen HPA-la by flow cytometry. Forty out of 2300 (1.7%) were found to be negative for this antigen . Of the 28 women followed throughout their pregnancy, none developed antibody to HPA-la. Platelet counts performed on samples from 17 babies born to 17 of these mothers were all normal. This study proves the simplicity and rapidity of flow cytometry for platelet antigen screening. The results were comparable with the Solid Phase Red Cell Adherence (SPRCA) method and with PCR. The lack of a plentiful supply of specific antibody and the rarity of fetomaternai alloimmune thrombocytopenia (FMAIT) argue against the introduction of routine screening for maternal HPA-la status at the present time.     

Psoas abscess in chronic dialysis patients

We report 4 cases of nontuberculous psoas abscess occurring in patients with end stage renal disease. Fever and pain were the presenting symptoms but diagnosis was delayed. A computerized tomography scan of the abdomen was the critical test that led to the correct diagnosis. Therapy involved drainage and antibiotics, and was successful in 3 of the 4 patients.     

Serial tomographic imaging with technetium-99m-sestamibi for the assessment of infarct-related arterial patency following reperfusion therapy.

The purpose of this study was to determine the relationship of changes in the severity and extent of hypoperfusion on serial tomographic 99mTc-sestamibi images with patency of the infarct related artery during acute myocardial infarction. We studied 109 patients with acute myocardial infarction using tomographic 99mTc-sestamibi imaging acutely and at 18-48 hr later. Perfusion defect extent and defect area, an index of defect severity, were measured on both studies. Both defect extent and defect area were significantly (p = 0.0001) greater for anterior infarctions than for inferior and lateral infarctions. By two factor analysis of variance, the change in defect area varied significantly with both infarct location (p = 0.0001) and patency of the infarct-related artery (p = 0.002). The change in defect extent also varied significantly with both infarct location (p = 0.0001) and with patency of the infarct-related artery (p = 0.004). In patients with inferior myocardial infarction, a change in defect extent or defect area of greater than 4% or 0.017, respectively, had a positive predictive accuracy of 96% and 93%, respectively, for the identification of a patent infarct artery. Therefore, sequential changes on tomographic 99mTc-sestamibi images are of potential value for the noninvasive assessment of patency of the infarct-related artery.     

The pathogenicity of Ab4p, the sequenced strain of equine herpesvirus-1, in specific pathogen-free foals.

The sequencing of the genome of equine herpesvirus-1 (EHV-1) is reported in Elizabeth A. R. Telford, Moira S. Watson, Kathryn McBride, and Andrew J. Davison, 1992, Virology, 189, 304-316. The sequence was derived using a plaque-purified clone of EHV-1 strain Ab4 (designated Ab4p). To ensure that Ab4p shares the pathogenic characteristics of parental Ab4 (hereafter Ab4), both were inoculated intranasally into foals, specifically free from EHV-1 and EHV-4. Clinical signs, including rectal temperature, were similar for both viruses. In addition, nasal shedding of virus was observed over a 1- to 2-week period postinfection, and viremia was established with both Ab4 and Ab4p. Isolation of virus from one foal following intravenous administration of steroids indicates that Ab4p can establish latency and undergo reactivation. Finally, retinal lesions were observed and these were similar to those seen with Ab4. In conclusion, several pathogenic characteristics of Ab4 are retained in the plaque-purified clone, Ab4p.     

Undergraduate and postgraduate dental students''reflection on learning'': a qualitative study

The aim of this study was to explore undergraduate and postgraduate dental students' understanding of a good learning experience by using 'reflection on learning' as described by Schon. Four groups of Year 4 BDS students and one group of postgraduate students in dental public health took part in a series of focus group discussions. The responses were grouped into four broad themes (a) active, practical and positive learning; (b) interactive/together learning; (c) personal learning; (d) theory into practice. Six educational models of good learning proposed by the students are described.     

多巴酚丁胺负荷对缺血性扩张型心肌病患者左心室充盈的影响：病理生理学及预后意义

目的：本研究旨在探讨多巴酚丁胺对缺血性心肌病（ICM）患者左心室（LV）充盈功能的影响，并确定峰值负荷时限制性充盈型（RFP）是否具有预后预测价值。背景：ICM患者峰值负荷时RFP的预后价值尚属未知。方法：在静息和负荷情况下，采用多普勒超声心动检查研究了69例ICM患者；RFP定义为跨二尖瓣E／A比≥1．0、等容舒张时间（IVRT）〈80ms及E波减速时间（EDT）〈120ms。结果：69例患者中有42例静息时出现RFP，其中有24例患者负荷情况下转变为非RFP（EA），18例患者RFP持续存在（EE）；69例患者中27例静息和峰值负荷时均无RFP（AA）。