This article summarizes the main elements, advantages, and disadvantages of Respondent-driven Sampling (RDS). Some criticisms regarding the feasibility of the inherent assumptions, their point estimators, and the obtained variances are pointed out. This article also comments on the problems observed in the quality of reports. Surveys using RDS should be methodologically sound as they are being applied to define priorities in health programs and develop national and international policies for financing service delivery, among other uses. However, there is considerable potential for bias related to implementation and analytical errors. There is limited empirical evidence on how representative the results obtained by RDS are, and the quest to improve the methodology is still in progress. Nevertheless, to have confidence in RDS results, we must verify that the social structure of the networks conforms to the assumptions required by the theory, that the sampling assumptions are reasonably fulfilled, and that the quality of the report is optimal, particularly for methodological and analytical items.

The P2X7 receptor, a member of the P2X purinergic receptor family, is a non-selective ion channel. Over the years, it has been associated with various biological functions, from modulating to regulating inflammation. However, its emerging role in antigen presentation has captured the scientific community’s attention. This function is essential for the immune system to identify and respond to external threats, such as pathogens and tumor cells, through T lymphocytes. New studies show that the P2X7 receptor is crucial for controlling how antigens are presented and how T cells are activated. These studies focus on antigen-presenting cells, like dendritic cells and macrophages. This review examines how the P2X7 receptor interferes with effective antigen presentation and activates T cells and discusses the fundamental mechanisms that can affect the immune response. Understanding these P2X7-mediated processes in great detail opens up exciting opportunities to create new immunological therapies.

To summarize the best available international scientific evidence on the effectiveness of interventions to reduce motor vehicle collisions and their consequences among the working and general populations. A broad and systematic review was conducted of the literature available in biomedical databases and grey literature. At least two investigators working in parallel performed data extraction, synthesis, and risk of bias analysis. Forty-one studies with low to moderate risk of bias were included. Of these, 18 had an ecological design (time series), 10 were quasi-experimental, one was a population survey, one was a randomized clinical trial, and 11 were systematic reviews. The interventions that most consistently show a positive effect on incidence, morbidity, and mortality due to motor vehicle collisions are national policies or programs that: regulate, enforce, and penalize driving under the influence of alcohol; improve driving safety and driver conditions; improve road infrastructure with the purpose of preventing collisions; and educate and penalize drivers with a history of road violations.