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Sub-micrometer-sized particles of poly(L-lactic acid) may be formed by using near-critical or supercritical carbon dioxide as an antisolvent to precipitate poly(L-lactic acid) from droplets of methylene chloride solution sprayed into a carbon dioxide continuous phase. Particle sizes may be controlled by varying the density of the carbon dioxide; at constant temperature in the supercritical region, higher carbon dioxide densities yield larger particles. Two methods (one batch and one continuous) for introducing the poly(L-lactic acid) solutions into carbon dioxide are demonstrated. Although the two methods use very different mechanisms for forming the droplets, similar particle sizes are observed as a function of carbon dioxide density. We suggest that mass transport, rather than jet breakup and hydrodynamics, controls particle sizes in the near-critical and supercritical regions.

Transcranial focused ultrasound technology used to transiently open the blood-brain barrier, is capable of stimulating hippocampal neurogenesis; however, it is not yet known what aspects of the treatment are necessary for enhanced neurogenesis to occur. The present study set out to determine whether the opening of blood-brain barrier, the specific pressure amplitudes of focused ultrasound, and/or the intravenous administration of microbubbles (phospholipid microspheres) are necessary for the enhancement of neurogenesis. Specifically, mice were exposed to burst (10ms, 1Hz burst repetition frequency) focused ultrasound at the frequency of 1.68MHz and with 0.39, 0.78, 1.56 and 3.0MPa pressure amplitudes. These treatments were also conducted with or without microbubbles, at 0.39 + 0.78MPa or 1.56 + 3.0MPa, respectively. Only focused ultrasound at the ~0.78 MPa pressure amplitude with microbubbles promoted hippocampal neurogenesis and was associated with an increase in blood-brain barrier permeability. These results suggest that focused ultrasound -mediated neurogenesis is dependent upon the opening of the blood-brain barrier.

BackgroundSuicidal behaviour remains challenging for clinicians to predict, with few established risk factors and warning signs among psychiatric patients.AimWe aimed to describe characteristics and identify risk factors for suicide attempts among patients with psychiatric disorders.MethodsMultivariable logistic regression analysis, adjusted for clinically important confounders, was employed to determine risk factors for suicide attempts within a psychiatric patient population.ResultsThe case (n = 146) and control groups (n = 104) did not differ significantly with regards to sociodemographic characteristics. The majority of the participants who had attempted suicide did so with high intent to die, and expected to die without medical intervention. The primary method of attempt was pharmaceutical overdose among the case participants (73.3%). Results showed impulsivity (odds ratio [OR] = 1.15, 95% confidence interval [CI] = 1.03–1.30) and borderline personality symptoms (OR = 1.07, 95% CI = 1.01–1.13) were significantly associated with attempted suicide.ConclusionsOur findings indicate that known sociodemographic risk factors for suicide may not apply within psychiatric populations. Prevention strategies for suicidal behaviour in psychiatric patients may be effective, including limited access to means for suicide attempts (i.e. excess pharmaceutical drugs) and target screening for high-risk personality and impulsivity traits.

Introduction Major depressive disorder is characterised by low mood and poor motivation. Literature suggests that increased physical activity has positive effects on alleviating depression. Fitness-tracking devices may complement behavioural activation (BA) therapy to improve physical activity and mental health in patients with depression. Objectives To understand patients’ perceived benefit from the Fitbit and explore themes associated with patient experiences. To compare perceived benefit, patient factors, Fitbit usage and Beck’s Depression Inventory (BDI) scores. Methods Semistructured interviews were conducted with patients (n=36) who completed a 28-week BA group programme in a mood disorders outpatient clinic. All patients were asked to carry a Fitbit One device. We conducted thematic analyses on the interviews and exploratory quantitative analyses on patient characteristics, Fitbit usage, steps recorded, perceived benefit and BDI scores. Findings Twenty-three patients found the Fitbit helpful for their physical activity. Themes of positive experiences included self-awareness, peer motivation and goal-setting opportunities. Negative themes included inconvenience, inaccuracies and disinterest. Age, baseline and change in BDI scores, prior physical activity goals and familiarity with technology were not associated with perceived benefit from the Fitbit or usage. Perceived benefit was significantly (p<0.01) associated with usage. Conclusions Overall, the Fitbit is an acceptable tool to complement BA therapy for patients with depression. Many positive themes were concordant with current literature; however, patients also reported negative aspects that may affect use. Clinical implications Clinicians and researchers should consider both strengths and limitations of activity trackers when implementing them to motivate patients with depression. Trial Registration Number NCT02045771; Pre-results.

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BackgroundIncluding content on Indigenous health in medical school curricula has become a widely-acknowledged prerequisite to reducing the health disparities experienced by Indigenous peoples in Canada. However, little is known about what levels of awareness and interest medical students have about Indigenous peoples when they enter medical school. Additionally, it is unclear whether current Indigenous health curricula ultimately improve students’ beliefs and behaviours.MethodsA total of 129 students completed a 43-item questionnaire that was sent to three cohorts of first-year medical students (in 2013, 2014, 2015) at one undergraduate medical school in Canada. This survey included items to evaluate students’ sociopolitical attitudes towards Indigenous people, knowledge of colonization and its links to Indigenous health inequities, knowledge of Indigenous health inequities, and self-rated educational preparedness to work with Indigenous patients. The survey also assessed students’ perceived importance of learning about Indigenous peoples in medical school, and their interest in working in an Indigenous community, which were examined as outcomes. Using principal component analysis, survey items were grouped into five independent factors and outcomes were modelled using staged multivariate regression analyses.ResultsGenerally, students reported strong interest in Indigenous health but did not believe themselves adequately educated or prepared to work in an Indigenous community. When controlling for age and gender, the strongest predictors of perceived importance of learning about Indigenous health were positive sociopolitical attitudes about Indigenous peoples and knowledge about colonization and its links to Indigenous health inequities. Significant predictors for interest in working in an Indigenous community were positive sociopolitical attitudes about Indigenous peoples. Knowledge about Indigenous health inequities was negatively associated with interest in working in an Indigenous community.ConclusionsStudents’ positive sociopolitical attitudes about Indigenous peoples is the strongest predictor of both perceived importance of learning about Indigenous health and interest in working in Indigenous communities. In addition to teaching students about the links between colonization, health inequities and other knowledge-based concepts, medical educators must consider the importance of attitude change in designing Indigenous health curricula and include opportunities for experiential learning to shape students’ future behaviours and ultimately improve physician relationships with Indigenous patients.Electronic supplementary materialThe online version of this article (10.1186/s12909-018-1401-1) contains supplementary material, which is available to authorized users.

The biosynthesis of diacylglycerols was studied in rat intestinal mucosa during in vivo absorption of a low molecular weight fraction fraction of butter oil and of the corresponding medium and long chain fatty acids. The experimental fat solutions were given by stomach tube to the animals after a 24-h fast and mucosal scraping were collected 3 h later. The lipids were isolated and the acylclycerols determined by combined thin-layer chromatography gas-liquid chromatography techniques and stereospecific analyses. Free fatty acid feeding led mainly to sn-1,2-diacyl-glycerols, which contained exogenous and endogenous fatty acids. During triacylglycerol feeding, both sn-1,2-and sn-2,3-diacylglycerols were recovered in significant amounts from the intestinal mucosa. The composition of the sn-2,3-diacylglycerols corresponded to that with exogenous fatty acids but the sn-1,2-diacylglycerols clearly contained both exogenous and endogenous fatty acids. In all cases it was possible to isolate endogenous sn-1,2-diacylglycerols made up largely of species with linoleic and arachidonic acids in the 2 position and palmitic and stearic acids in the 1 position, which apparently were not converted to triacylglycerols. The in vivo reacylation of 2-monoacylglycerols via both sn-1,2- and sn-2,3-diacylglycerols is in agreement with similar findings in vitro with everted sacs of rat intestinal mucosa.