Changes in myocardial echo amplitude during reversible ischaemia in humans.

OBJECTIVE--This study investigated the changes in regional myocardial ultrasonic backscatter, measured as myocardial echo amplitude, that occur during reversible myocardial ischaemia in humans. DESIGN--Left anterior descending coronary angioplasty was used to produce reversible myocardial ischaemia in human subjects. Regional myocardial echo amplitude was studied in the interventricular septum and left ventricular posterior free wall before, during, and after coronary occlusion with the angioplasty balloon. Wall motion analysis of the left ventricle was performed from simultaneous cross sectional echocardiographic imaging. Patients were studied prospectively. PATIENTS--Six patients (mean age 56 (SD 11), range 46 to 69 years) with single vessel, left anterior descending coronary artery stenoses, were investigated during elective coronary angioplasty. A total of 11 balloon inflations were studied. SETTING--All patient studies were performed at Harefield Hospital. Echo amplitude analysis was performed at the Royal Brompton Hospital. INTERVENTIONS--Angioplasty was performed by the usual procedure at Harefield Hospital for elective coronary angioplasty. All routine medication including beta blockers and calcium antagonists were continued. Inflation pressures were up to 12 atm (1212 kPa) and mean inflation time ranged from 30 to 120 (86 (31)) s. In four studies the first inflation was examined, in three the second, in two the third, and in one each the fourth and fifth inflations. Echo amplitude and cross sectional echo-cardiographic studies were recorded with a 3.5 MHz Advanced Technology Laboratories (ATL) (720A/8736 series) mechanical sector scanner and an ATL Mark III (860-1 series) echocardiograph system with 45 dB logarithmic grey scale compression. MAIN OUTCOME MEASURES--Regional echo amplitude was examined in four regions of the left ventricle--namely, the basal and mid-septum, and basal and mid-posterior wall. Consecutive end diastolic and end systolic frames were analysed and cyclic variation was determined as the difference between the level of echo amplitude at end diastole and at end systole. Measurements were made before balloon inflation, at peak inflation, and after balloon deflation. Regional wall motion and systolic wall thickening were analysed qualitatively. RESULTS--Before balloon inflation, cyclic variation in echo amplitude was noted in all regions (basal septum, 2.4 (SD 1.1) dB; mid-septum, 2.5 (1.1) dB; basal posterior wall, 3.3 (2.1) dB; mid-posterior wall, 3.9 (1.6) dB). During balloon inflation there was a significant fall in cyclic variation to 0.4 (0.9) dB (p < 0.0002) in the mid-septum. This was predominantly owing to an increase in end systolic echo amplitude from 5.4 (2.0) dB to 9.3 (1.9) dB (p < or = 0.01). This was associated with the development of severe hypokinesis or akinesis in the mid-septum. No significant changes in echo amplitude occurred in the three other regions examined. Changes were completely reversed after balloon deflation. CONCLUSIONS--These results suggest a causal relation between occlusion of the supplying coronary artery and blunting of myocardial echo amplitude cyclic variation. It is suggested that balloon occlusion produced myocardial ischaemia. The resultant impairment of myocardial contraction then caused a blunting of cyclic variation in echo amplitude. The results of this study provide further data about the ability of quantitative studies of ultrasonic backscatter to identify alterations in the myocardium during injury.     

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）。     

The influence of clinical problems, age and social support on outcomes for elderly persons referred to regional aged care assessment teams

Abstract Background: Aged Care Assessment Teams (ACATs) have been established throughout Australia during the past seven years. Early studies of their effect have concentrated on their impact on the rate of institutionalisation of disabled elderly, the clinical characteristics of referred cases and the relationship between disability and recommended care plan. Aims: The aim of this study was to explore the relationship between age, clinical features and social characteristics of AC AT subjects with outcomes at 12 months after assessment. Methods: The examination of an arbitrary sample of persons referred to ACATs over a year by one generalist geriatrician with follow-up of all cases by the three ACATs associated with the study was carried out. All analyses were performed on raw data presented as categorical variables in the form of contingency tables. Results: The sample included 324 subjects who suffered from 2030 clinical problems with a mean of 6.5 per person aged 75 or over and 5.5 for those under 75. Cardiovascular and neurological disease were the commonest source of problems. Study of accommodation outcome at 12 months, for those subjects who survived this period revealed that, in the older group, over 60% of subjects with neurological disease were resident in nursing homes while the majority of all other groups remained in the community, as did two-thirds of those aged under 75. Admission to a nursing home was independent of social support for older subjects with neurological disease, but it played a significant role in those with cardiopulmonary or musculoskeletal disease. Conclusions: The study demonstrates that for one-year survivors there is an increased likelihood of admission to a nursing home of people aged 75 or over with neurological disease, while those under 75 were more likely to remain at home. The association was independent of whether spouse, family or friends were living with the subject. (Aust NZ J Med 1994; 24: 378–385.)     

The effectiveness of intranasal corticosteroids in combined allergic rhinitis and asthma syndrome

Background Allergic rhinitis (AR) and asthma often coexist and may represent two manifestations of the same disease recently named combined AR and asthma syndrome (CARAS). Aim To review the common pathophysiology of combined AR and asthma and to investigate the efficacy of intranasal corticosteroids (INCS). Methods Medline was used to identify articles relevant to mechanisms. A Cochrane systematic review was performed to assess the efficacy of INCS in CARAS. Results There is cross‐talk, evidence of a common inflammatory response in both sites, linked by a systemic component. The efficacy of anti‐inflammatory INCS on asthma outcomes was assessed in a systematic review of 12 randomized controlled trials involving 425 subjects. After INCS there were non‐significant trends for improvement in asthma symptom score (standardized mean difference (SMD) of 0.61; P=0.07), forced expiratory volume in 1 s (SMD of 0.31; P=0.08), and morning peak expiratory flow (weighted mean difference of 36.51; P=0.06). There was no impact on methacholine airways responsiveness (SMD of ?0.20; P=0.4). The review identified two promising new treatment options in united airway disease such as INCS as monotherapy in rhinitis and mild asthma, and a combined intranasal and intrabronchial corticosteroid (IBCS) deposition technique. Conclusion Common mucosal inflammatory responses occur in CARAS. This systematic review shows trends for a benefit of INCS in CARAS, but recognizes that more research is needed. At this stage, the current best practice is to treat asthma conventionally with IBCS with or without β₂‐agonist and to add INCS to improve specific rhinitis symptoms.     

Haematology and biochemistry in healthy young pheasants and red-legged partridges and effects of spironucleosis on these parameters.

Plasma biochemical and haematological parameters were examined in 4-week-old to 12-week-old game birds. Healthy, uninfected pheasants and partridges had similar levels of total protein, albumin, osmolality, Na+, Cl-, K+, Mg2+ and glucose. Triglyceride, globulin and Ca2+ were significantly higher and PO43- was lower in the partridges. Pheasants carrying a light to moderate infection with Spironucleus had significantly lower total protein, albumin, osmolality, Na+, Cl-, Ca2+ and PO43-. In severely affected pheasants, the osmolality, Na+ and Cl- fell further. Triglyceride and glucose were significantly lower than in healthy birds, and Mg2+ was higher. Similar data were obtained from infected partridges. Red cell parameters rose significantly in pheasants severely affected by spironucleosis, and the percent of heterophils was significantly higher and lymphocytes and basophils lower in their blood smears. The breast and leg muscle wet weight from severely affected pheasants was 22.2 and 37.7% that of uninfected birds, although the water content of the breast muscle was significantly higher.