La médecine ambulatoire youth-friendly. [Youth-friendly outpatient care].

Ambulatory pediatric and family medicine takes care of adolescent patients, most of whom regularly consult a physician. Consultations with young people involve issues specifically related to their age. Regarding health care systems and physicians, adolescents' expectations vary from those of adults, not so much in terms of the issues discussed but in terms of the priorities that they give to them. Confidential interviews are not always proposed but are highly appreciated, as are certain personal qualities on the part of the caregivers such as honesty, respect, and friendliness. Finally, easy access to care together with the continuity of care are essential. Prevention of risk behaviors by screening and health education is clearly insufficient. This issue could be approached during the consultation through a psychosocial history. This is a good opportunity to discuss sensitive issues that adolescents seldom bring up themselves. More systematic prevention would probably decrease youth morbidity and mortality, which are both closely related to risk behaviors. To meet these expectations and special health care needs, the World Health Organization has developed the concept of youth-friendly health services. This concept can be applied in both a specialized adolescence center and a pediatric or family practice. Youth-friendly services are still rarely evaluated but seem to bring a clear benefit in terms of patient satisfaction and access to care.

Prestress in the extracellular matrix sensitizes latent TGF-β1 for activation.

Integrin-mediated force application induces a conformational change in latent TGF-β1 that leads to the release of the active form of the growth factor from the extracellular matrix (ECM). Mechanical activation of TGF-β1 is currently understood as an acute process that depends on the contractile force of cells. However, we show that ECM remodeling, preceding the activation step, mechanically primes latent TGF-β1 akin to loading a mechanical spring. Cell-based assays and unique strain devices were used to produce a cell-derived ECM of controlled organization and prestrain. Mechanically conditioned ECM served as a substrate to measure the efficacy of TGF-β1 activation after cell contraction or direct force application using magnetic microbeads. The release of active TGF-β1 was always higher from prestrained ECM as compared with unorganized and/or relaxed ECM. The finding that ECM prestrain regulates the bioavailability of TGF-β1 is important to understand the context of diseases that involve excessive ECM remodeling, such as fibrosis or cancer.

The squeeze cell hypothesis for the activation of jasmonate synthesis in response to wounding

Jasmonates are lipid mediators that control defence gene expression in response to wounding and other environmental stresses. These small molecules can accumulate at distances up to several cm from sites of damage and this is likely to involve cell-to-cell jasmonate transport. Also, and independently of jasmonate synthesis, transport and perception, different long-distance wound signals that stimulate distal jasmonate synthesis are propagated at apparent speeds of several cmmin(-1) to tissues distal to wounds in a mechanism that involves clade 3 GLUTAMATE RECEPTOR-LIKE (GLR) genes. A search for jasmonate synthesis enzymes that might decode these signals revealed LOX6, a lipoxygenase that is necessary for much of the rapid accumulation of jasmonic acid at sites distal to wounds. Intriguingly, the LOX6 promoter is expressed in a distinct niche of cells that are adjacent to mature xylem vessels, a location that would make these contact cells sensitive to the release of xylem water column tension upon wounding. We propose a model in which rapid axial changes in xylem hydrostatic pressure caused by wounding travel through the vasculature and lead to slower, radially dispersed pressure changes that act in a clade 3 GLR-dependent mechanism to promote distal jasmonate synthesis.