The dmrt1 (doublesex and mab-3 related transcription factor 1) gene is a key regulator of sex determination and/or gonadal sex differentiation across metazoan animals. This is unusual given that sex determination genes are typically not well conserved. The mechanisms by which zebrafish sex is determined have remained elusive due to the lack of sex chromosomes and the complex polygenic nature of sex determination in domesticated strains. To investigate the role of dmrt1 in zebrafish sex determination and gonad development, we isolated mutations disrupting this gene. We found that the majority of dmrt1 mutant fish develop as fertile females suggesting a complete male-to-female sex reversal in mutant animals that would have otherwise developed as males. A small percentage of mutant animals became males, but were sterile and displayed testicular dysgenesis. Therefore zebrafish dmrt1 functions in male sex determination and testis development. Mutant males had aberrant gonadal development at the onset of gonadal sex-differentiation, displaying reduced oocyte apoptosis followed by development of intersex gonads and failed testis morphogenesis and spermatogenesis. By contrast, female ovaries developed normally. We found that Dmrt1 is necessary for normal transcriptional regulation of the amh (anti-Müllerian hormone) and foxl2 (forkhead box L2) genes, which are thought to be important for male or female sexual development respectively. Interestingly, we identified one dmrt1 mutant allele that cooperates with a linked segregation distorter locus to generate an apparent XY sex determination mechanism. We conclude that dmrt1 is dispensable for ovary development but necessary for testis development in zebrafish, and that dmrt1 promotes male development by transcriptionally regulating male and female genes as has been described in other animals. Furthermore, the strong sex-ratio bias caused by dmrt1 reduction-of-function points to potential mechanisms through which sex chromosomes may evolve.

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BackgroundPosterior fossa craniotomies can be complicated by cerebrospinal fluid (CSF) leaks, infection, meningitis, neurologic deficits, and intracranial hypotension caused by defective closure of the dura. Secondary dural closures such as pericranial graft, muscle graft, glue, sealants, or fat graft are used. However, there have been few studies examining the use of sealants with a polyethylene glycol and polyethylenimine component.

Purpose:Recent data suggest great variability in costs for surgical hospitalization for spinal surgery. However, the magnitude of expenditures attributable to complications is unknown. The purpose of this study is to describe cost of care associated with surgical and medical complications after cervical spine surgery.Materials and Methods:A retrospective cohort study utilizing the National Inpatient Sample years 2002–2014 was conducted. A weighted sample of 901,508 adults undergoing elective cervical fusion for degenerative indications was extracted using diagnostic and procedure codes. Twelve categories of major complications were identified, and patient/hospital variables were evaluated as predictors of the overall reimbursed cost using multivariate regression. Mean differences (B) and 95% confidence intervals were reported.Results:The mean age was 52.2 ± 11.4 years, with 5.2% of patients experiencing a complication. Mean overall increase in inflation-adjusted cost associated with complication was $16,435 ± 10,358, varying significantly by type of complication, surgical approach, and number of levels fused. The most common complications and their attributed costs were dysphagia (1.6%, B = $2624 [2476–2771], P < 0.001), pulmonary complications (1.0%, B = $9334 [9110–9558], P < 0.001), and device-related complications (0.9%, B = $3125 [2927–3324], P < 0.001). The costliest complications were infection (0.1%, B = $25359 [24723–25994], P < 0.001), thromboembolism (0.1%, B = $17480 [16808–18153], P < 0.001), and neurological complications (0.2%, B = $10098 [9629–10567], P < 0.001).Conclusions:Although complications are rare after elective cervical fusion, they are associated with dramatically increase costs of care as high as $25,359 in the setting of postoperative infection. Improved understanding of the economic magnitude of complications may help guide efforts in reducing health care spending and improving perioperative care.

The annual incidence of mild traumatic brain injury (MTBI) is 3.8 million in the USA with 10–15% experiencing persistent morbidity beyond one year. Chronic traumatic encephalopathy (CTE), a neurodegenerative disease characterized by accumulation of hyperphosphorylated tau, can occur with repetitive MTBI. Risk factors for CTE are challenging to identify because injury mechanisms of MTBI are heterogeneous, clinical manifestations and management vary, and CTE is a postmortem diagnosis, making prospective studies difficult. There is growing interest in the genetic influence on head trauma and development of CTE. Apolipoprotein epsilon 4 (APOE-ε4) associates with many neurologic diseases, and consensus on the ε4 allele as a risk factor is lacking. This review investigates the influence of APOE-ε4 on MTBI and CTE. A comprehensive PubMed literature search (1966 to 12 June 2018) identified 24 unique reports on the topic (19 MTBI studies: 8 athletic, 5 military, 6 population-based; 5 CTE studies: 4 athletic and military, 1 leucotomy group). APOE-ε4 genotype is found to associate with outcomes in 4/8 athletic reports, 3/5 military reports, and 5/6 population-based reports following MTBI. Evidence on the association between APOE-ε4 and CTE from case series is equivocal. Refining modalities to aid CTE diagnosis in larger samples is needed in MTBI.

While cancer-associated fibroblasts (CAFs) and their pro-tumoral effects have been demonstrated in systemic cancers, CAFs had been presumed absent in glioblastoma given the lack of normal fibroblasts in the healthy brain. Here, we show that 5–26% (mean=12%) of cells in human glioblastomas express CAF markers α-SMA or PDGFR-β, morphologically resemble fibroblasts, and transcriptomically resemble by RNA-seq CAFs from other cancers. Glioblastoma CAFs were chemotactically attracted to glioblastoma-initiating stem cells (P=0.02). While glioblastoma CAFs did not affect differentiated glioblastoma cell proliferation (P=0.4), CAFs increased glioblastoma stem cell proliferation (P=0.002) and expression of glioblastoma stem cell-associated genes (P< 0.001). To identify mediators of CAF/glioblastoma stem cell interactions, we created a resource of inferred crosstalk by mapping the expression of receptors to that of their cognate ligands/agonists, using our RNA-seq results from glioblastoma CAFs and stem cells, revealing PDGF-β/PDGFR and osteopontin/CD44 to mediate stem cell recruitment of CAFs and CAF enrichment of stem cells, as confirmed by blocking antibodies (P=0.02–0.03). CAFs also render the glioblastoma microenvironment more pro-tumoral by promoting M2 polarization of tumor-associated macrophages (P=0.01), an effect we found to arise from unique CAF production of the EDA splice variant of fibronectin binding toll-like receptor 4 (TLR4), a known EDA receptor expressed by macrophages (P=0.02). In patient glioblastomas, CAFs were enriched 3-fold in the subventricular zone (SVZ) (P=0.04) which houses the neural stem cells that generate glioblastoma stem cells. SVZs from epilepsy cases or autopsies of glioblastoma-containing brains without ventricular involvement lacked CAFs. Depleting CAFs in xenografts derived from neurosphere-containing glioblastoma stem cells slowed their growth in vivo (P< 0.001). These findings are among the first to identify and profile glioblastoma CAFs. CAF recruitment by glioblastoma stem cells and creation of a pro-tumoral microenvironment in the perivascular niche housing glioblastoma stem cells, particularly in the SVZ, makes them an intriguing therapeutic target.

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