Characterization of Procoagulant COAT Platelets in Patients with Glanzmann Thrombasthenia.

Patients affected by the rare Glanzmann thrombasthenia (GT) suffer from defective or low levels of the platelet-associated glycoprotein (GP) IIb/IIIa, which acts as a fibrinogen receptor, and have therefore an impaired ability to aggregate platelets. Because the procoagulant activity is a dichotomous facet of platelet activation, diverging from the aggregation endpoint, we were interested in characterizing the ability to generate procoagulant platelets in GT patients. Therefore, we investigated, by flow cytometry analysis, platelet functions in three GT patients as well as their ability to generate procoagulant collagen-and-thrombin (COAT) platelets upon combined activation with convulxin-plus-thrombin. In addition, we further characterized intracellular ion fluxes during the procoagulant response, using specific probes to monitor by flow cytometry kinetics of cytosolic calcium, sodium, and potassium ion fluxes. GT patients generated higher percentages of procoagulant COAT platelets compared to healthy donors. Moreover, they were able to mobilize higher levels of cytosolic calcium following convulxin-plus-thrombin activation, which is congruent with the greater procoagulant activity. Further investigations will dissect the role of GPIIb/IIIa outside-in signalling possibly implicated in the regulation of platelet procoagulant activity

Predictors of residential stability among homeless young adults : a cohort study.

Abstract : BACKGROUND: Homelessness episodes have been shown to be associated with serious health outcomes among youth. This study was undertaken to estimate the probability of reaching residential stability over time and to identify predictors of residential stability among homeless young adults aged 18 to 25 years. METHODS: A prospective cohort study was carried out in Montréal, Canada, between April 5(th) 2006 and January 21(th) 2009. Interviews conducted every three months included questions on life conditions and social and mental health factors that are known to influence residential trajectories. Residential status was determined, starting on the first day after recruitment; each follow-up day was classified as a homeless day or a housed day. A period of 90 days was used to define residential stability; therefore the main study outcome was the occurrence of the first consecutive 90 housed days during the follow-up period. Kaplan-Meier and Cox proportional-hazards regression analyses were conducted. RESULTS: Of the 359 participants, 284 reached 90 days of residential stability over the study period, representing an annual probability of 80.5 %. In multivariate analysis, youth who had a high school degree, had a formal sector activity, and those who had sought psychological help were more likely to reach residential stability. Being a man, injecting substances, and having an informal sector activity were associated with a decreased probability to reach residential stability. CONCLUSION: Exposure to factors related to opportunities that promote social integration increases the chance of reaching residential stability. On the other hand, factors related to high level of street entrenchment seem to interfere with stabilization. Maximum efforts should be made to prevent chronic homelessness among youth, targeting not only individual impairments but also hinging on services adapted to foster social connections among the youth

Old-field succession along a precipitation gradient in the semi-arid coastal region of Tenerife

Secondary succession on abandoned fields was studied in the semi-arid region of Tenerife (Canary Islands). At four different sites along a precipitation gradient four chronosequences were sampled. On the whole, 11 fields, abandoned for eight to 70 years, and adjacent near-tonatural stands were studied, with regard to species richness, species composition, vegetation structure, life form distribution and the importance of endemic/exotic species, using uni- and multivariate statistical methods. In the three drier chronosequences species richness increased significantly during succession whereas in the wettest sequence it peaked very early with a subsequent decline towards the mature stand. Temporal changes in floristic composition were significant and revealed clear directional trends. We could distinguish two pathways of succession: one for the northern coast under more humid conditions and one for the southern coast under arid conditions. Therophytes were generally substituted by nanophanerophytes, while hemicryptophytes and chamaephytes showed low abundances with peaks in late successional stages. At all sites, endemic species replaced exotic species, with regard to both relative number and cover. The relative importance of exotic species in early succession increased with increasing precipitation. Cover of perennials, stand height and stand biomass increased with time since abandonment and water availability. Floristic composition recovered faster than stand structure and, in particular, stand biomass. We have the following conclusions (i) The absence of disturbance and in presence of nearto-natural stands in the surroundings, coastal scrub on Tenerife has the capacity to regenerate completely albeit slowly after traditional agricultural use. (ii) The rate and pathway of succession are influenced by site productivity, i.e. mean annual precipitation. (iii) Life form distribution changed in the second phase of succession in relation with the precipitation gradient. (iv) The initially dominant exotic annual plant species seem to be a temporary problem only since, in the course of succession, they are substituted by native perennials. r 2005 Elsevier Ltd. All rights reserved

A manual of elementary instruction, for ... schools and normal classes;

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Response of a subalpine grassland to simulated grazing: aboveground productivity along soil phosphorus gradients

Interactions between grassland ecosystems and vertebrate herbivores are critical for a better understanding of ecosystem processes, but diverge widely in different ecosystems. In this study, we examined plant responses to simulated red deer ( Cervus elaphus L.) grazing using clip-plot experiments in a subalpine grassland ecosystem of the Central European Alps. We measured aboveground net primary production (ANPP) and phosphorus (P) concentration of leaf tissue from plants of two vegetation types with different grazing history. The experimental plots were placed on a soil-P gradient and subject to two different clipping treatments, which simulated moderate and heavy grazing, respectively. We found distinct differences in the response of both ANPP and P concentration in leaf tissues in the two vegetation types. Compared to moderate, heavy grazing simulation did not affect ANPP in the vegetation type adapted to grazing, but decreased ANPP in the non-grazing adapted vegetation type. High soil-P levels also had different effects on the response of the vegetation to clipping in the two vegetation types with different grazing history. ANPP correlated positively with soil-P in non-grazing adapted tall-grass vegetation, while in grazing adapted short-grass vegetation a positive relationship between soil-P and the P concentration in leaf tissues was found. Our experiments provide data for a better understanding of ecosystem processes in high-elevation grasslands of the Alps with possible implications for both nature conservation purposes in protected areas and the management of agriculturally used grasslands

Criminalisation of clients : reproducing vulnerabilities for violence and poor health among street-based sex workers in Canada : a qualitative study

Objectives To explore how criminalisation and policing of sex buyers (clients) rather than sex workers shapes sex workers’ working conditions and sexual transactions including risk of violence and HIV/sexually transmitted infections (STIs). Design Qualitative and ethnographic study triangulated with sex work-related violence prevalence data and publicly available police statistics. Setting Vancouver, Canada, provides a unique opportunity to evaluate the impact of policies that criminalise clients as the local police department adopted a sex work enforcement policy in January 2013 that prioritises sex workers’ safety over arrest, while continuing to target clients. Participants 26 cisgender and 5 transgender women who were street-based sex workers (n=31) participated in semistructured interviews about their working conditions. All had exchanged sex for money in the previous 30 days in Vancouver. Outcome measures Thematic analysis of interview transcripts and ethnographic field notes focused on how police enforcement of clients shaped sex workers’ working conditions and sexual transactions, including risk of violence and HIV/STIs, over an 11-month period postpolicy implementation (January–November 2013). Results Sex workers’ narratives and ethnographic observations indicated that while police sustained a high level of visibility, they eased charging or arresting sex workers and showed increased concern for their safety. However, participants’ accounts and police statistics indicated continued police enforcement of clients. This profoundly impacted the safety strategies sex workers employed. Sex workers continued to mistrust police, had to rush screening clients and were displaced to outlying areas with increased risks of violence, including being forced to engage in unprotected sex. Conclusions These findings suggest that criminalisation and policing strategies that target clients reproduce the harms created by the criminalisation of sex work, in particular, vulnerability to violence and HIV/STIs. The current findings support decriminalisation of sex work to ensure work conditions that support the health and safety of sex workers in Canada and globally.Medicine, Faculty ofOther UBCNon UBCMedicine, Department ofReviewedFacultyResearcherGraduateOthe