Three-dimensional architecture of epithelial primary cilia.

We report a complete 3D structural model of typical epithelial primary cilia based on structural maps of full-length primary cilia obtained by serial section electron tomography. Our data demonstrate the architecture of primary cilia differs extensively from the commonly acknowledged 9+0 paradigm. The axoneme structure is relatively stable but gradually evolves from base to tip with a decreasing number of microtubule complexes (MtCs) and a reducing diameter. The axonemal MtCs are cross-linked by previously unrecognized fibrous protein networks. Such an architecture explains why primary cilia can elastically withstand liquid flow for mechanosensing. The nine axonemal MtCs in a cilium are found to differ significantly in length indicating intraflagellar transport processes in primary cilia may be more complicated than that reported for motile cilia. The 3D maps of microtubule doublet-singlet transitions generally display longitudinal gaps at the inner junction between the A- and B-tubules, which indicates the inner junction protein is a major player in doublet-singlet transitions. In addition, vesicles releasing from kidney primary cilia were observed in the structural maps, supporting that ciliary vesicles budding may serve as ectosomes for cell-cell communication.

Access to Contraceptives in School-Based Health Centers: Progress and Opportunities.

INTRODUCTION: The U.S. has a higher adolescent pregnancy rate than other industrialized countries. School-based health centers can improve access to contraceptives among youth, which can prevent unplanned pregnancies. This cross-sectional study examines the characteristics and predictors of contraceptive provision at school-based health centers in 2016-2017 and changes in and barriers to provision between 2001 and 2017. METHODS: In 2020-2021, the authors conducted analyses of the National School-Based Health Care Census data collected from 2001 to 2017. The primary outcome of interest was whether adolescent-serving school-based health centers dispense contraceptives, and a secondary outcome of interest was the policies that prohibit school-based health centers from dispensing contraceptives. A multivariate regression analysis examined the associations between contraceptive provision and various covariates, including geographic region, years of operation, and provider team composition. RESULTS: Less than half of adolescent-serving school-based health centers reported providing contraceptives on site. Those that provided contraceptives were more likely located in the Western and Northeastern regions of the U.S., older in terms of years of operation, and staffed by a wide variety of health provider types. Among school-based health centers that experienced policy barriers to providing access to contraceptive methods, most attributed the source to the school or school district where the school-based health center was located. CONCLUSIONS: School-based health centers are an evidence-based model for providing contraceptives to adolescents but not enough are providing direct access. Understanding the predictors, characteristics, and barriers influencing the provision of contraceptives at school-based health centers may help to expand the number doing so.

The Developmental Process of the Growing Motile Ciliary Tip Region.

Eukaryotic motile cilia/flagella play vital roles in various physiological processes in mammals and some protists. Defects in cilia formation underlie multiple human disorders, known as ciliopathies. The detailed processes of cilia growth and development are still far from clear despite extensive studies. In this study, we characterized the process of cilium formation (ciliogenesis) by investigating the newly developed motile cilia of deciliated protists using complementary techniques in electron microscopy and image analysis. Our results demonstrated that the distal tip region of motile cilia exhibit progressive morphological changes as cilia develop. This developmental process is time-dependent and continues after growing cilia reach their full lengths. The structural analysis of growing ciliary tips revealed that B-tubules of axonemal microtubule doublets terminate far away from the tip end, which is led by the flagellar tip complex (FTC), demonstrating that the FTC might not directly mediate the fast turnover of intraflagellar transport (IFT).

An open letter to my daughter.

The author writes a poignant "open" letter to her daughter about her experience with breast cancer, the family legacy of breast cancer, and the impact of learning there is a BRCA1 mutation in the family.