Glial Patchwork: Oligodendrocyte Progenitor Cells and Astrocytes Blanket the Central Nervous System.

Tiling is a developmental process where cell populations become evenly distributed throughout a tissue. In this review, we discuss the developmental cellular tiling behaviors of the two major glial populations in the central nervous system (CNS)-oligodendrocyte progenitor cells (OPCs) and astrocytes. First, we discuss OPC tiling in the spinal cord, which is comprised of the three cellular behaviors of migration, proliferation, and contact-mediated repulsion (CMR). These cellular behaviors occur simultaneously during OPC development and converge to produce the emergent behavior of tiling which results in OPCs being evenly dispersed and occupying non-overlapping domains throughout the CNS. We next discuss astrocyte tiling in the cortex and hippocampus, where astrocytes migrate, proliferate, then ultimately determine their exclusive domains by gradual removal of overlap rather than sustained CMR. This results in domains that slightly overlap, allowing for both exclusive control of "synaptic islands" and astrocyte-astrocyte communication. We finally discuss the similarities and differences in the tiling behaviors of these glial populations and what remains unknown regarding glial tiling and how perturbations to this process may impact injury and disease.

Purging of malignant cell contamination prior to spermatogonia stem cell autotransplantation to preserve fertility: progress & prospects.

PURPOSE OF REVIEW: This systematic review evaluates the state of the art in terms of strategies used to detect and remove contaminated malignant cells from testicular biopsy prior to spermatogonia stem cells (SSCs) autotransplantation to restore fertility. RECENT FINDINGS: Several trials have been done in past two decades to determine the reliable methods of detecting and purging cancer cells prior to SSCs autotransplantation. SUMMARY: The success in treating childhood cancer has dramatically increased over the past few decades. This leads to increasing demand for a method of fertility preservation for patients with pediatric cancer, as many cancer therapies can be gonadotoxic. Storing the SSCs prior to chemo- or radiation therapies and transplanting them back has been tested as a method of restoring fertility in rodents and nonhuman primate models. This has promise for restoring fertility in childhood cancer survivors. One of the major concerns is the possibility of malignant cell presence in testicular tissue biopsies that could re-introduce cancer to the patient after SSCs autotransplantation. Non-solid cancers - especially hematologic malignancies - have the risk of being transplanted back into patients after SSCs cryopreservation even if they were only present in small number in the stored testicular tissue biopsy.

Identity tensions in lesbian intercollegiate coaches.

Using social identity perspective, we investigated the experiences of 13 lesbian college coaches. Through semistructured interviews, the coaches revealed the daily identity tensions they experienced. There was constant negotiation between their social identities of "coach" and "lesbian." The social context of intercollegiate women's athletics created a complex web that juxtaposed these identities against commanding social norms. The challenges these coaches faced ranged from doing what they believed was best for the well being of their athletes (e.g., fighting homonegativism) versus what was best for their professional well being (e.g., remaining silent). These coaches did not passively accept their fate; while they struggled with identity negotiation, they also found ways to counter the heterosexist atmosphere and create positive social change.