DNA helicases are motor proteins that play essential roles in DNA replication, repair and recombination. In the replicative hexameric helicase, the fundamental reaction is the unwinding of duplex DNA; however, our understanding of this function remains vague due to insufficient structural information. Here, we report two crystal structures of the DnaB-family replicative helicase from Geobacillus kaustophilus HTA426 (GkDnaC) in the apo-form and bound to single-stranded DNA (ssDNA). The GkDnaC–ssDNA complex structure reveals that three symmetrical basic grooves on the interior surface of the hexamer individually encircle ssDNA. The ssDNA-binding pockets in this structure are directed toward the N-terminal domain collar of the hexameric ring, thus orienting the ssDNA toward the DnaG primase to facilitate the synthesis of short RNA primers. These findings provide insight into the mechanism of ssDNA binding and provide a working model to establish a novel mechanism for DNA translocation at the replication fork.

IMPORTANCE Hidradenitis suppurativa (HS) and inflammatory bowel disease (IBD) are inflammatory diseases that share common genetic susceptibility and immunologic features. However, the link between HS and IBD has been largely unclear. OBJECTIVE To conduct a meta-analysis to investigate the association between HS and IBD. DATA SOURCES A search of the MEDLINE, Cochrane Central Register of Controlled Trials, and Embase databases yielded 397 relevant studies from inception to June 10, 2018. Two additional studies were supplied by one of the investigators. STUDY SELECTION Case-control, cross-sectional, or cohort studies that examined the odds or risk of IBD in patients with HS were included. No geographic or language limitations were imposed. DATA EXTRACTION AND SYNTHESIS The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The Newcastle-Ottawa Scale was used to assess the risk of bias of included studies. Crohn disease and ulcerative colitis were analyzed separately, and a random-effects model meta-analysis was conducted. MAIN OUTCOMES AND MEASURES The odds ratios (ORs) and hazard ratios (HRs) of IBD, Crohn disease, and ulcerative colitis in association with HS. RESULTS Five case-control studies, 2 cross-sectional studies, and 1 cohort study with a total of 93 601 unique participants were included. The meta-analysis of case-control and cross-sectional studies showed significant associations of HS with Crohn disease (pooled OR, 2.12; 95% CI, 1.46-3.08) and ulcerative colitis (pooled OR, 1.51; 95% CI, 1.25-1.82). Two case-control studies found significant association of HS with IBD (ORs, 2.16 [95% CI, 1.40-3.34] and 10.00 [95% CI, 1.94-51.50]). One cohort study found an increased risk of IBD in patients with HS (HR, 5.6; 95% CI not reported; P < .002). CONCLUSIONS AND RELEVANCE The evidence to date supports an association of HS with IBD. These results suggest that consultation with gastroenterologists should be sought when patients with HS present with recurrent abdominal pain, chronic diarrhea, bloody stool, and body weight loss.

International health experts agree that China is on the verge of an AIDS crisis. In response, the Chinese government initiated the “Four Frees and One Care” policy in 2003 to decrease economic barriers and increase access to antiretroviral therapies for people with HIV. However, long-term treatment success requires not only access, but high rates of medication adherence. This qualitative interview study with 29 persons receiving HIV care at Beijing’s Ditan Hospital identified barriers to and facilitators of medication adherence. The interviews were guided by an a priori conceptual model of adherence with four components: access, knowledge about medications, motivation, and proximal cues to action. Barriers to adherence were related to stigma and fear of discrimination; the medications themselves (including side effects and complicated dosing regimens); and other economic issues (i.e., costs of transportation, lab tests, and hospitalizations). Facilitators included participants’ strong will to live, use of electronic reminders, and family support. These results support the conceptual model and suggest that successful interventions must minimize stigma as it negatively affects all components of the model for adherence.