Hypersensitivity pneumonitis: evaluation with CT

Thirteen chest radiographs and computed tomographic (CT) scans obtained from 11 patients with hypersensitivity pneumonitis were reviewed. The CT findings were correlated with open lung biopsy findings in seven patients. The two patients with acute hypersensitivity pneumonitis showed air-space opacification on CT scans. An open lung biopsy, done in one of these patients, demonstrated noncaseating granulomas and filling of the air spaces with macrophages. The nine patients with subacute hypersensitivity pneumonitis showed small, rounded opacities and patchy air-space opacification on CT scans. These findings reflected the histologic findings, which consisted of interstitial pneumonitis, cellular bronchiolitis, and small, noncaseating granulomas. The six patients with symptoms for 12 months or longer also showed irregular linear opacities on CT scans, corresponding to areas of fibrosis. CT scans were superior to radiographs in helping to assess the type and extent of abnormalities, and high-resolution CT scans were superior to conventional CT scans.     

Is the structure of anatomy curriculum adequate for safe medical practice?

IntroductionAnatomy has been considered a core subject within the medical education curriculum. In the current setting of ever-changing diagnostic and treatment modalities, the opinion of both students and trainers is crucial for the design of an anatomy curriculum which fulfils the criteria required for safe medical practice.MethodsMedical students, trainees and specialist trainee doctors and specialists from the London (England) area were surveyed to investigate the how curriculum changes have affected the relevance of anatomical knowledge to clinical practice and to identify recommendations for optimum teaching methods. The survey employed 5-point Likert scales and multiple-choice questions. Where the effect of training level was statistically significant (p < 0.05), post-hoc analysis was carried out using Mann–Whitney U tests. Significance levels were modified according to the Bonferroni method.ResultsTwo hundred and twenty-eight individuals completed the survey giving a response rate of 53%. Medical students, trainees and specialists all agreed (mean Likert score 4.51, 4.79, 4.69 respectively) that knowledge of anatomy is important for medical practice. Most of the trainees (88.4%) and specialists (81.3%) used dissection to learn anatomy, but only 61.4% of medical students used this approach. Dissection was the most commonly recommended approach for learning anatomy across all the groups (41.7%–69.3%).ConclusionsKnowledge of anatomy is perceived to be important for safe clinical practice. Anatomy should be taught with other relevant system or clinical modules. Newer tools for anatomy teaching need further validation before incorporation into the curriculum.     

Is the 'athlete's heart' arrhythmogenic? Implications for sudden cardiac death

Whether the ventricular hypertrophic response to athletic training can predispose to fatal ventricular dysrhythmias via mechanisms similar to that of pathological hypertrophy is controversial. This review examines current information regarding the metabolic and electrophysiological differences between the myocardial hypertrophy of heart disease and that associated with athletic training. In animal studies, the biochemical and metabolic profile of physiological hypertrophy from exercise training can largely be differentiated from that of pathological hypertrophy, but it is not clear if the former might represent an early stage in the spectrum of the latter. Information as to whether the electrical remodelling of the athlete's heart mimics that of patients with heart disease, and therefore serves as a substrate for ventricular dysrhythmias, is conflicting. If ventricular remodelling associated with athletic training can trigger fatal dysrhythmias, such cases are extraordinarily rare and thereby impossible to investigate by any standard experimental approach. Greater insight into this issue may come from a better understanding of the electrical responses to both acute bouts of exercise and chronic training in young athletes.     

Climate change and human health: Possible communicable disease consequences in the united kingdom

In May 1990 a ‘Think Tank’ was constituted? in order to advise the Director of the Public Health Laboratory Service (PHLS) on the potential effects of global climatic change, and of world population increase and movements, on the epidemiology of infectious diseases internationally and in the United Kingdom, and to consider the implications for the PHLS. This article draws on the Think Tank deliberations and describes the scenario considered, and some of the major issues identified, with particular reference to the UK.     

Venting intraluminal drains in pancreaticoduodenectomy

The utility of placing biliary, pancreatic, or enteric "venting"tubes (externally draining devices traversing the bowel or bile duct that have their distal tip located intraluminally near the biliary or pancreatic anastomosis) when performing a pancreaticoduodenectomy has received little attention to date. We hypothesize that these venting tubes do not decrease the morbidity or mortality associated with pancreatico-duodenectomy and may actually be a source of additional morbidity. To characterize our use of and the effect of these drains, we retrospectively analyzed 136 pancreaticoduodenectomies (127 partial, 9 total) performed over a 24-month period. Venting drain use, drain type and size, drain location, duration of intubation, hospital course, and postoperative complications were noted. Venting tubes were used in 80 patients (59%). The use of these drains had no significant relationship to postoperative length of stay, the development of major complications, overall morbidity, or mortality (P >0.05). Such drains also did not significantly shorten the length of hospital stay (P >0.05) or improve outcome when available to augment local control following luminal leak (n = 6) or regional abscess (n = 7). These drains were removed at a median interval of 29 days postoperatively (range 6 to 77 days). Seven patients had complications that were directly related to the venting drain; four of these patients had a documented infra-abdominal luminal leak from the site of drain removal, whereas the other three were hospitalized for presumed leakage secondary to immediate, severe abdominal pain following removal of the drain. These seven patients were elderly (mean age 70 years) and often harbored pancreatic ductal carcinoma (n = 6). Intraluminal drains afford no distinct advantage in terms of shortening the postoperative length of stay, decreasing operative morbidity and mortality, or improving local control with regional sepsis in pancreaticoduodenectomies. Furthermore, they may add an additional source of morbidity and we no longer employ them routinely.     

Loss of serotonin uptake sites and immunoreactivity in rat cortex after dexfenfluramine occur without parallel glial cell reactions

The frontal cortices of rats which received eitherd,l- ord-fenfluramine (DFEN) for 4 days were examined 18 h to 2 weeks following treatment for changes in synaptosomal uptake of serotonin (5HT), paroxetine binding, 5HT-immunoreactivity (5HT-IR), and both astrocytic (GFAP) and microglial markers. Additional rats received intracerebroventricular injections of the neurotoxin 5,7-dihydroxytryptamine (DHT). Consistent with previous reports,d,l- and DFEN produced dose-dependent losses of both 5HT uptake and paroxetine binding, and loss of 5HT-IR which coincided with an abnormal or ‘swollen’ appearance of immunoreactive axon processes. Recovery of these serotonergic indices was greatest following the lowest doses of DFEN, but was absent after 5,7-DHT treatment. No evidence for an increase in GFAP synthesis or microglial activation was observed in frontal cortices of rats treated with either DFEN or 5,7-DHT. We conclude that the presence of swollen 5HT-IR axons in the cortices of both the 5,7-DHT and DFEN groups is insufficient to trigger the glial responses often associated with neuronal degeneration. Thus, it remains to be determined if swollen 5HT-IR axons are a prelude to neurodegeneration, or whether they represent reversible changes in axonal immunochemistry associated with decreases in 5HT levels. The implications of the data for the clinical safety of DFEN are briefly discussed.     

Aligning Developmental and Processing Accounts of Implicit and Statistical Learning

A long‐standing question in child language research concerns how children achieve mature syntactic knowledge in the face of a complex linguistic environment. A widely accepted view is that this process involves extracting distributional regularities from the environment in a manner that is incidental and happens, for the most part, without the learner's awareness. In this way, the debate speaks to two associated but separate literatures in language acquisition: statistical learning and implicit learning. Both fields have explored this issue in some depth but, at present, neither the results from the infant studies used by the statistical learning literature nor the artificial grammar learning tasks studies from the implicit learning literature can be used to fully explain how children's syntax becomes adult‐like. In this work, we consider an alternative explanation—that children use error‐based learning to become mature syntax users. We discuss this proposal in the light of the behavioral findings from structural priming studies and the computational findings from Chang, Dell, and Bock's (2006) dual‐path model, which incorporates properties from both statistical and implicit learning, and offers an explanation for syntax learning and structural priming using a common error‐based learning mechanism. We then turn our attention to future directions for the field, here suggesting how structural priming might inform the statistical learning and implicit learning literature on the nature of the learning mechanism.     

Interhemispheric visual competition after multisensory reversal of hemianopia

Unilateral lesions of visual cortex have the secondary consequence of suppressing visual circuits in the midbrain superior colliculus (SC), collectively producing blindness in contralesional space (“hemianopia”). Recent studies have demonstrated that SC visual responses and contralesional vision can be reinstated by a non‐invasive multisensory training procedure in which spatiotemporally concordant visual‐auditory pairs are repeatedly presented within the blind hemifield. Despite this recovery of visual responsiveness, the loss of visual cortex was expected to result in permanent deficits in that hemifield, especially when visual events in both hemifields compete for attention and access to the brain's visuomotor circuitry. This was evaluated in the present study in a visual choice paradigm in which the two visual hemifields of recovered cats were simultaneously stimulated with equally valent visual targets. Surprisingly, the expected disparity was not found, and some animals even preferred stimuli presented in the previously blind hemifield. This preference persisted across multiple stimulus intensity levels and there was no indication that animals were less aware of cues in the previously blind hemifield than in its spared counterpart. Furthermore, when auditory cues were combined with visual cues, the enhanced performance they produced on a visual task was no greater in the normal than in the previously blind hemifield. These observations suggest that the multisensory rehabilitation paradigm revealed greater inherent visual information processing potential in the previously blind hemifield than was believed possible given the loss of visual cortex.