Microstructural basis of contusion expansion in traumatic brain injury: insights from diffusion tensor imaging

Traumatic brain injury (TBI) is often exacerbated by events that lead to secondary brain injury, and represent potentially modifiable causes of mortality and morbidity. Diffusion tensor imaging was used to characterize tissue at-risk in a group of 35 patients scanned at a median of 50 hours after injury. Injury progression was assessed in a subset of 16 patients with two scans. All contusions within the first few days of injury showed a core of restricted diffusion, surrounded by an area of raised apparent diffusion coefficient (ADC). In addition to these two well-defined regions, a thinner rim of reduced ADC was observed surrounding the region of increased ADC in 91% of patients scanned within the first 3 days after injury. In patients who underwent serial imaging, the rim of ADC hypointensity was subsumed into the high ADC region as the contusion enlarged. Overall contusion enlargement tended to be more frequent with early lesions, but its extent was unrelated to the time of initial imaging, initial contusion size, or the presence of hemostatic abnormalities. This rim of hypointensity may characterize a region of microvascular failure resulting in cytotoxic edema, and may represent a ‘traumatic penumbra'' which may be rescued by effective therapy.     

Economic Evaluation of Community-Based HIV Prevention Programs in Ontario: Evidence of Effectiveness in Reducing HIV Infections and Health Care Costs

Investments in community-based HIV prevention programs in Ontario over the past two and a half decades are assumed to have had an impact on the HIV epidemic, but they have never been systematically evaluated. To help close this knowledge gap, we conducted a macro-level evaluation of investment in Ontario HIV prevention programs from the payer perspective. Our results showed that, from 1987 to 2011, province-wide community-based programs helped to avert a total of 16,672 HIV infections, saving Ontario’s health care system approximately $6.5 billion Canadian dollars (range 4.8–7.5B). We also showed that these community-based HIV programs were cost-saving: from 2005 to 2011, every dollar invested in these programs saved about $5. This study is an important first step in understanding the impact of investing in community-based HIV prevention programs in Ontario and recognizing the impact that these programs have had in reducing HIV infections and health care costs.     

Fibrosis with emphysema

Wright J L, Tazelaar H D & Churg A (2011) Histopathology  58 , 517–524
Fibrosis with emphysema The concept of fibrosis with emphysema is confused by the existence of two very different clinical/pathological scenarios: first, cases in which a diffuse fibrosing interstitial pneumonia, most commonly usual interstitial pneumonia (UIP), occurs in a patient with emphysema. This combination is largely of clinical interest because of its effects on pulmonary function and pulmonary hypertension, but can produce unusual appearances in surgical lung biopsies when the fibrotic areas are wrapped around emphysematous spaces. However, the underlying morphology of emphysema and UIP or other interstitial lung disease remains unchanged. Radiological consultation is often helpful to show that the patient has both lesions; secondly, cases in which there is localized fibrosis that is part of emphysema, or related to respiratory bronchiolitis, or both. These lesions have been called ‘respiratory bronchiolitis’ (RB), ‘respiratory bronchiolitis–interstitial lung disease’ (RB‐ILD), ‘airspace enlargement with fibrosis’, ‘RB‐ILD with fibrosis’ and ‘clinically occult interstitial fibrosis in smokers’, but are probably all the same entity. Such changes are associated only rarely with the physiological or radiological features of an interstitial lung disease. Care should be taken when describing these lesions in biopsies so as not to give the impression that a diffuse interstitial lung disease is present.     

Pharmacology podcasts: a qualitative study of non-medical prescribing students' use,perceptions and impact on learning

Background  

There is growing research on student use of podcasts in academic settings. However, there is little in-depth research focusing on student experience of podcasts, in particular in terms of barriers to, and facilitators of, podcast use and students' perceptions of the usefulness of podcasts as learning tools. This study aimed to explore the experiences of non-medical prescribing students who had access to podcasts of key pharmacology lectures as supplementary learning tools to their existing course materials.     

BMC Medicine celebrates its 5th anniversary

In November 2008, BMC Medicine passed the landmark of its first 5 years of publishing. When we launched the journal with the aim of publishing high quality research of general interest and special importance, we had no idea what the future would bring. To mark the occasion of our 5^th anniversary, we consider the achievements of the last 5 years and discuss our plans for the future.