Sex in mammals is genetically determined and is defined at the cellular level by sex chromosome complement (XY males and XX females). The Y chromosome-linked gene sex-determining region Y (SRY) is believed to be the master initiator of male sex determination in almost all eutherian and metatherian mammals, functioning to upregulate expression of its direct target gene Sry-related HMG box-containing gene 9 (SOX9). Data suggest that SRY evolved from SOX3, although there is no direct functional evidence to support this hypothesis. Indeed, loss-of-function mutations in SOX3 do not affect sex determination in mice or humans. To further investigate Sox3 function in vivo, we generated transgenic mice overexpressing Sox3. Here, we report that in one of these transgenic lines, Sox3 was ectopically expressed in the bipotential gonad and that this led to frequent complete XX male sex reversal. Further analysis indicated that Sox3 induced testis differentiation in this particular line of mice by upregulating expression of Sox9 via a similar mechanism to Sry. Importantly, we also identified genomic rearrangements within the SOX3 regulatory region in three patients with XX male sex reversal. Together, these data suggest that SOX3 and SRY are functionally interchangeable in sex determination and support the notion that SRY evolved from SOX3 via a regulatory mutation that led to its de novo expression in the early gonad.

Severe and severe-complicated Clostridium difficile infection (CDI) is associated with high morbidity and mortality. Colectomy is standard of care; however, post-surgical mortality rates approach 50%. Case reports suggest fecal microbiota transplant (FMT) is a promising treatment of severe and severe-complicated disease but there is a paucity of data. Here, we present a single center experience with a novel sequential FMT protocol for patients refractory to maximal medical therapy. This approach consists of at least one FMT delivered via colonoscopy with criteria for repeat FMT and continued vancomycin therapy based on clinical response and pseudomembranes. Our cohort included 57 consecutive inpatients diagnosed with severe or severe-complicated CDI and treated with FMT. Overall, 91% (52/57) experienced clinical cure at 1 month with a 100% cure rate among severe CDI (n = 19) patients and an 87% cure rate for severe-complicated CDI (n = 33) patients. For the cohort, the survival rate was 94.7% at 1 month and 78.6% at 3 months. There were no serious adverse events related to FMT including no procedure-related complications or perforation. There was no difference in outcome between fresh or frozen fecal material. Sequential FMT for inpatients with severe or severe-complicated CDI is promising and may be preferred over colectomy in certain patients.

SUMMARY BackgroundSevere and severe/complicated Clostridium difficile infection (CDI) can result in ICU admission, sepsis, toxic megacolon and death. In this setting, colectomy is the standard of care but it is associated with a 50% mortality.

Background: The value of narrow band imaging (NBI) for detecting serrated lesions is

BACKGROUND & AIMS:Fecal microbiota transplantation (FMT) is recommended for recurrent Clostridioides difficile infection (CDI). FMT cures nearly 80% of patients with severe or fulminant CDI (SFCDI) when utilized in a sequential manner. We compared outcomes of hospitalized patients before and after implementation of an FMT program for SFCDI and investigated whether the changes could be directly attributed to the FMT program. METHODS:We performed a retrospective analysis of characteristics and outcomes of patients hospitalized for SFCDI (430 hospitalizations) at a single center, from January 2009 through December 2016.We performed subgroup analyses of 199 patients with fulminant CDI and 110 patients with refractory SFCDI (no improvement after 5 or more days of maximal anti-CDI antibiotic therapy). We compared CDI-related mortality within 30 days of hospitalization, CDI-related colectomy, length of hospital stay, and readmission to the hospital within 30 days before (2009-2012) vs after (2013-2016) implementation of the inpatient FMT program. RESULTS:CDI-related mortality and colectomy were lower after implementation of the FMT program.Overall, CDI-related mortality was 10.2% before the FMT program was implemented vs 4.4% after (P [ .02). For patients with fulminant CDI, CDI-related mortality was 21.3% before the FMT program was implemented vs 9.1% after (P [ .015). For patients with refractory SFCDI, CDIrelated mortality was 43.2% before the FMT program vs 12.1% after (P < .001). The FMT program significantly reduced CDI-related colectomy in patients with SFCDI (6.8% before vs 2.7% after; P [ .041), in patients with fulminant CDI (15.7% before vs 5.5% after; P [ .017), and patients with refractory SFCDI (31.8% vs 7.6%; P [ .001). The effect of FMT program implementation on CDI-related mortality remained significant for patients with refractory SFCDI after we accounted for the underlying secular trend (odds ratio, 0.09 for level change; P [ .023). CONCLUSIONS:An FMT program significantly decreased CDI-related mortality among patients hospitalized with refractory SFCDI.

Previous studies have shown that Sox3 is expressed in nascent neuroprogenitor cells and is functionally required in mammals for development of the dorsal telencephalon and hypothalamus. However, Sox3 expression during embryonic and adult neurogenesis has not been examined in detail. Using a SOX3-specific antibody, we show that murine SOX3 expression is maintained throughout telencephalic neurogenesis and is restricted to progenitor cells with neuroepithelial and radial glial morphologies. We also demonstrate that SOX3 is expressed within the adult neurogenic regions and is coexpressed extensively with the neural stem cell marker SOX2 indicating that it is a lifelong marker of neuroprogenitor cells. In contrast to the telencephalon, Sox3 expression within the developing hypothalamus is upregulated in developing neurons and is maintained in a subset of differentiated hypothalamic cells through to adulthood. Together, these data show that Sox3 regulation is region-specific, consistent with it playing distinct biological roles in the dorsal telencephalon and hypothalamus.

Conflict of Interest Disclosures: JRA consults for and has research support from Finch Therapeutics. MF serves as consultant for Finch Therapeutics Group and DSMB member for Rebiotix. CSK is on the scientific advisory board for Bio-Rad Laboratories. The remaining authors have no conflicts to disclose.

Our observations expand the spectrum of phenotypes observed in association with altered SOX3 dosage and may affect the approach to genetic screening. Screening for SOX3 should be advised not only for hypopituitary patients with an ectopic posterior pituitary, but also for those with a structurally normal pituitary and additional findings, including clefts and a persistent craniopharyngeal canal, with or without mental retardation.