Synthesis of N-Tosyl Allylic Amines from Substituted Alkenes via Vanadoxaziridine Catalysis.

Herein, we report the catalytic allylic amination of α-methylalkenes with V2O3Dipic2(HMPA)2 and chloramine T as the quantitative source of N. The reaction works with high yields and stereoselectivities for α-methylalkenes. A proposed tosylnitrene-free catalytic cycle involving the formation of vanadoxaziridine complex 1 as the active catalyst and aminovanadation across the substrate as the rate-determining step has been proposed. Initial kinetic and competition experiments provide evidence for the proposed mechanism.

Introduction: the 12th Biennial Rivkin Center Ovarian Cancer Research Symposium.

In September 2018, the 12th Biennial Ovarian Cancer Research Symposium was presented by the Rivkin Center for Ovarian Cancer and the American Association for Cancer Research, in Seattle, WA, USA. The 2018 Symposium focused on four broad areas of research: Detection and Prevention of Ovarian Cancer, Genomics and Molecular Mechanisms of Ovarian Cancer, Tumor Microenvironment and Immunology of Ovarian Cancer, and Novel Therapeutics: Response and Resistance of Ovarian Cancer. In addition, a special panel on the 'Role of Advocates in Ovarian Cancer Research' was featured.

Analysis of the clonal growth and differentiation dynamics of primitive barcoded human cord blood cells in NSG mice.

Human cord blood (CB) offers an attractive source of cells for clinical transplants because of its rich content of cells with sustained repopulating ability in spite of an apparent deficiency of cells with rapid reconstituting ability. Nevertheless, the clonal dynamics of nonlimiting CB transplants remain poorly understood. To begin to address this question, we exposed CD34+ CB cells to a library of barcoded lentiviruses and used massively parallel sequencing to quantify the clonal distributions of lymphoid and myeloid cells subsequently detected in sequential marrow aspirates obtained from 2 primary NOD/SCID-IL2Rγ(-/-) mice, each transplanted with ∼10(5) of these cells, and for another 6 months in 2 secondary recipients. Of the 196 clones identified, 68 were detected at 4 weeks posttransplant and were often lympho-myeloid. The rest were detected later, after variable periods up to 13 months posttransplant, but with generally increasing stability throughout time, and they included clones in which different lineages were detected. However, definitive evidence of individual cells capable of generating T-, B-, and myeloid cells, for over a year, and self-renewal of this potential was also obtained. These findings highlight the caveats and utility of this model to analyze human hematopoietic stem cell control in vivo.

Enhanced normal short-term human myelopoiesis in mice engineered to express human-specific myeloid growth factors.

UNLABELLED: Better methods to characterize normal human hematopoietic cells with short-term repopulating activity cells (STRCs) are needed to facilitate improving recovery rates in transplanted patients.We now show that 5-fold more human myeloid cells are produced in sublethally irradiated NOD/SCID-IL-2Receptor-γchain-null (NSG) mice engineered to constitutively produce human interleukin-3, granulocyte-macrophage colony-stimulating factor and Steel factor (NSG-3GS mice) than in regular NSG mice 3 weeks after an intravenous injection of CD34 human cord blood cells. Importantly, the NSG-3GS mice also show a concomitant and matched increase in circulating mature human neutrophils. Imaging NSG-3GS recipients of lenti-luciferase-transduced cells showed that human cells being produced 3 weeks posttransplant were heterogeneously distributed, validating the blood as a more representative measure of transplanted STRC activity. Limiting dilution transplants further demonstrated that the early increase in human granulopoiesis in NSG-3GS mice reflects an expanded output of differentiated cells per STRC rather than an increase in STRC detection. KEY POINTS: NSG-3GS mice support enhanced clonal outputs from human short-term repopulating cells (STRCs) without affecting their engrafting efficiency. Increased human STRC clone sizes enable their more precise and efficient measurement by peripheral blood monitoring.

Distinct but phenotypically heterogeneous human cell populations produce rapid recovery of platelets and neutrophils after transplantation.

Delayed recovery of mature blood cells poses a serious, expensive, and often life-threatening problem for many stem cell transplantation recipients, particularly if heavily pretreated and serving as their own donor, or having a CB transplantation as the only therapeutic option. Importantly, the different cells required to ensure a rapid, as well as a permanent, hematopoietic recovery in these patients remain poorly defined. We now show that human CB and mobilized peripheral blood (mPB) collections contain cells that produce platelets and neutrophils within 3 weeks after being transplanted into sublethally irradiated NOD/scid-IL-2Rγc-null mice. The cells responsible for these 2 outputs are similarly distributed between the aldehyde dehydrogenase-positive and -negative subsets of lineage marker-negative CB and mPB cells, but their overall frequencies vary independently in individual samples. In addition, their total numbers can be seen to be much (> 30-fold) lower in a single "average" CB transplantation compared with a single "average" mPB transplantation (normalized for a similar weight of the recipient), consistent with the published differential performance in adult patients of these 2 transplantation products. Experimental testing confirmed the clinical relevance of the surrogate xenotransplantation assay for quantifying cells with rapid platelet regenerative activity, underscoring its potential for future applications.

Development, Implementation, and Meta-Evaluation of a National Approach to Programmatic Assessment in Canadian Family Medicine Residency Training.

The growing international adoption of competency-based medical education has created a desire for descriptions of innovative assessment approaches that generate appropriate and sufficient information to allow for informed, defensible decisions about learner progress. In this article, the authors provide an overview of the development and implementation of the approach to programmatic assessment in postgraduate family medicine training programs in Canada, called Continuous Reflective Assessment for Training (CRAFT). CRAFT is a principles-guided, high-level approach to workplace-based assessment that was intentionally designed to be adaptable to local contexts, including size of program, resources available, and structural enablers and barriers. CRAFT has been implemented in all 17 Canadian family medicine residency programs, with each program taking advantage of the high-level nature of the CRAFT guidelines to create bespoke assessment processes and tools appropriate for their local contexts. Similarities and differences in CRAFT implementation between 5 different family medicine residency training programs, representing both English- and French-language programs from both Western and Eastern Canada, are described. Despite the intentional flexibility of the CRAFT guidelines, notable similarities in assessment processes and procedures across the 5 programs were seen. A meta-evaluation of findings from programs that have published evaluation information supports the value of CRAFT as an effective approach to programmatic assessment. While CRAFT is currently in place in family medicine residency programs in Canada, given its adaptability to different contexts as well as promising evaluation data, the CRAFT approach shows promise for application in other training environments.

Analysis of parameters that affect human hematopoietic cell outputs in mutant c-kit-immunodeficient mice.

Xenograft models are transforming our understanding of the output capabilities of primitive human hematopoietic cells in vivo. However, many variables that affect posttransplantation reconstitution dynamics remain poorly understood. Here, we show that an equivalent level of human chimerism can be regenerated from human CD34+ cord blood cells transplanted intravenously either with or without additional radiation-inactivated cells into 2- to 6-month-old NOD-Rag1-/--IL2Rγc-/- (NRG) mice given a more radioprotective conditioning regimen than is possible in conventionally used, repair-deficient NOD-Prkdcscid/scid-IL2Rγc-/- (NSG) hosts. Comparison of sublethally irradiated and non-irradiated NRG mice and W41/W41 derivatives showed superior chimerism in the W41-deficient recipients, with some differential effects on different lineage outputs. Consistently superior outputs were observed in female recipients regardless of their genotype, age, or pretransplantation conditioning, with greater differences apparent later after transplantation. These results define key parameters for optimizing the sensitivity and minimizing the intraexperimental variability of human hematopoietic xenografts generated in increasingly supportive immunodeficient host mice.

Characterization of a new full length TMPRSS3 isoform and identification of mutant alleles responsible for nonsyndromic recessive deafness in Newfoundland and Pakistan.

BACKGROUND: Mutant alleles of TMPRSS3 are associated with nonsyndromic recessive deafness (DFNB8/B10). TMPRSS3 encodes a predicted secreted serine protease, although the deduced amino acid sequence has no signal peptide. In this study, we searched for mutant alleles of TMPRSS3 in families from Pakistan and Newfoundland with recessive deafness co-segregating with DFNB8/B10 linked haplotypes and also more thoroughly characterized the genomic structure of TMPRSS3. METHODS: We enrolled families segregating recessive hearing loss from Pakistan and Newfoundland. Microsatellite markers flanking the TMPRSS3 locus were used for linkage analysis. DNA samples from participating individuals were sequenced for TMPRSS3. The structure of TMPRSS3 was characterized bioinformatically and experimentally by sequencing novel cDNA clones of TMPRSS3. RESULTS: We identified mutations in TMPRSS3 in four Pakistani families with recessive, nonsyndromic congenital deafness. We also identified two recessive mutations, one of which is novel, of TMPRSS3 segregating in a six-generation extended family from Newfoundland. The spectrum of TMPRSS3 mutations is reviewed in the context of a genotype-phenotype correlation. Our study also revealed a longer isoform of TMPRSS3 with a hitherto unidentified exon encoding a signal peptide, which is expressed in several tissues. CONCLUSION: Mutations of TMPRSS3 contribute to hearing loss in many communities worldwide and account for 1.8% (8 of 449) of Pakistani families segregating congenital deafness as an autosomal recessive trait. The newly identified TMPRSS3 isoform e will be helpful in the functional characterization of the full length protein.