Effects of cardiac oscillations and lung volume on acinar gas mixing during apnea

We evaluated the importance of cardiogenic gas mixing in the acini of 13 dogs during 2 min of apnea. 133Xe (1-2 mCi in 4 ml of saline) was injected into an alveolar region through an occluded pulmonary artery branch, and washout was measured by gamma scintillation scanning during continued occlusion or with blood flow reinstated. The monoexponential rate constant for Xe washout (XeW) was -0.4 +/- 0.08 (SE) min-1 at functional residual capacity (FRC) with no blood flow in the injected region. It decreased by more than half at lung volumes 500 ml above and 392 ml below FRC. With intact pulmonary blood flow, XeW was -1.0 +/- 0.08 (SE) min-1 at FRC, and it increased with decreasing lung volume. However, if calculated Xe uptake by the blood was subtracted from the XeW measured with blood flow intact, resulting values at FRC and at FRC + 500 ml were not different from XeW with no blood flow. Reasonable calculation of Xe blood uptake at 392 ml below FRC was not possible because airway closure, increased shunt, and other factors affect XeW. After death, no significant XeW could be measured, which suggests that XeW caused by molecular diffusion was small. We conclude that 1) the effect of heart motion on the lung parenchyma increases acinar gas mixing during apnea, 2) this effect diminishes above or below FRC, and 3) there is probably no direct effect of pulmonary vascular pulsatility on acinar gas mixing.     

Attempted Isolation of Cryptococcus Species and Incidental Isolation of Exophiala dermatitidis from Human Oral Cavities

Mycopathologia - Recent molecular studies suggest that Cryptococcus may inhabit the normal human mouth. We attempted to isolate Cryptococcus from 21 adult non-acutely ill patients and 40 volunteer...     

Light emitting diode-red light for reduction of post-surgical scarring: Results from a dose-ranging,split-face,randomized controlled trial

Scarring has significant esthetic and functional consequences for patients. A need exists for anti-scarring therapeutics. Light emitting diode-red light (LED-RL) has been shown to modulate skin fibrosis. The aim of this study is to evaluate the safety and efficacy of LED-RL to reduce post-operative scarring. Cutaneous Understanding of Red-light Efficacy on Scarring was a randomized, mock-controlled, single-blind, dose-ranging, split-face phase II clinical trial. Starting 1 week post-surgery, patients received LED-RL irradiation and temperature-controlled mock therapy to incision sites at fluences of 160, 320 or 480 J/cm², triweekly for 3 weeks. Efficacy was assessed at 1, 3 and 6–12 months. The primary endpoint was difference in scar pliability between LED-RL-treated and control sites. Secondary outcomes included Patient and Observer Scar Assessment Scale, collagen and water concentration, and adverse events. There were no significant differences in scar pliability between treated and control scars. At certain fluences, treated scars showed greater improvements in observer rating and scar pliability, reflected by greater reductions in induration, from baseline to 6 months compared to control scars. Treatment-site adverse events included blistering (n = 2) and swelling (n = 1), which were mild and resolved without sequelae. LED-RL phototherapy is safe in the early postoperative period and may reduce scarring.     

Everything and nothing: regulating embryo research in Canada

This article examines how medical and scientific professionals experience and engage with the governance of embryo research in Canada. Drawing on the history of embryo regulation in Canada and the findings of a survey conducted with lab directors in Canadian fertility clinics, we identify a disjuncture between the rules established by legislation, regulations, and research ethics guidelines and the real-life experiences of professionals in the field. This disjuncture, we argue, is the result of both the absence of implementation mechanisms that would give substance to the governing framework, as well as an inability on the part of medical and scientific professionals to engage in robust self-regulation. Overall, we demonstrate that in an ethically charged and highly technical area of policy-making like embryonic research, clarity about the roles and responsibilities of government and professionals in policy-making and implementation is critical to effective governance.