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The inflammatory response goes haywire after stroke, and the brain floods with immune mediators that can injure tissue and worsen outcome. Experiments in mice suggest that regulatory T cells help contain the damage (pages 192–199).
Osteoporosis researchers do not suffer from a lack of potential drug targets—so one challenge is to decide which ones to focus on. Yongwon Choi, Matthew C. Walsh and Joseph R. Arron now examine several molecules involved in bone biology and assess their prospects. In a second commentary, Cliff Rosen analyzes findings that serotonin, derived from the gut, regulates bone formation. The findings not only could lead to new drug targets, they also could help explain clinical data that serotonin reuptake inhibitors—widely prescribed as antidepressants—weaken bones.
Influenza virus vaccination for young children living in the US state of New Jersey and who are attending preschool is now compulsory—a mandate that has highlighted a flourishing public mistrust of vaccines.
Experiments in mice and zebrafish uncover a pathway behind malformed blood vessels in the brain (pages 169–176 & 177–184). The findings provide a basis for understanding the development of cerebral vascular malformations, a common and deadly condition.
A molecular pathway requiring vitamin B3 increases the production of neutrophils (pages 151–158). These findings could lead to new ways to treat neutropenias, diseases involving low neutrophil counts.
Researchers are enrolling thousands of participants around the world in clinical trials in a massive effort to test whether a once-daily pill can prevent HIV. Cassandra Willyard explores why they are optimistic the strategy will work and why it might be difficult to implement.
Last month, Michel Sidibé assumed his new role as executive director of UNAIDS, the United Nations agency created more than a decade ago to foster global leadership in the response to the AIDS pandemic. Sidibé discussed his new goals as executive director of UNAIDS with Prashant Nair.
Does Mycobacterium tuberculosis replicate in vivo, or does it persist in the host in a nonreplicating latent state? David Sherman and his colleagues have developed a technique to answer this question in mice and find that the mycobacteria do replicate in vivo. It is unknown whether these findings will hold true in other animals, particularly nonhuman primates, but this technique could be applied to study the in vivo replication of other persistent pathogens responsible for chronic infections.
In this report, Skokowa et al. delineate a new molecular pathway by which synthesis of the metabolite NAD+ through the action of the enzyme NAMPT promotes myeloid cell differentiation. The potential clinical relevance of this pathway was demonstrated by showing that administration of vitamin B3, a precursor to NAD+, increases neutrophil counts in healthy individuals, and that defective myeloid cell differentiation in individuals with congenital neutropenia can be rescued in vitro by administration of NAMPT.