Oxidation, Coordination, and Nickel-Mediated Deconstruction of a Highly Electron-Rich Diboron Analogue of 1,3,5-Hexatriene

The reductive coupling of an N-heterocyclic carbene (NHC) stabilized (dibromo)vinylborane yields a 1,2-divinyldiborene, which, although isoelectronic to a 1,3,5-triene, displays no extended π conjugation because of twisting of the C2B2C2 chain. While this divinyldiborene coordinates to copper(I) and platinum(0) in an η2-B2 and η4-C2B2 fashion, respectively, it undergoes a complex rearrangement to an η4-1,3-diborete upon complexation with nickel(0)

BCL11A enhancer edited hematopoietic stem cells persist in rhesus monkeys without toxicity

Gene editing of the erythroid-specific BCL11A enhancer in hematopoietic stem and progenitor cells (HSPCs) from sickle cell disease (SCD) patients induces fetal hemoglobin (HbF) without detectable toxicity as assessed by mouse xenotransplant. Here, we evaluated autologous engraftment and HbF induction potential of erythroid-specific BCL11A enhancer edited HSPCs in four non-human primates. We utilized a single guide RNA (sgRNA) with identical human and rhesus target sequences to disrupt a GATA1 binding site at the BCL11A +58 erythroid enhancer. Cas9 protein and sgRNA ribonucleoprotein complex (RNP) was electroporated into rhesus HSPCs, followed by autologous infusion after myeloablation. We found that gene edits persisted in peripheral blood (PB) and bone marrow (BM) for up to 101 weeks similarly for BCL11A enhancer or control locus (AAVS1) targeted cells. Biallelic BCL11A enhancer editing resulted in robust gamma-globin induction, with the highest levels observed during stress erythropoiesis. Indels were evenly distributed across PB and BM lineages. Off-target edits were not observed. Non-homologous end-joining repair alleles were enriched in engrafting HSCs. In summary, we find that edited HSCs can persist for at least 101 weeks post-transplant, and biallelic edited HSCs provide substantial HbF levels in PB red blood cells, together supporting further clinical translation of this approach

Vision 20/20: Molecular-guided surgical oncology based upon tumor metabolism or immunologic phenotype: Technological pathways for point of care imaging and intervention

Surgical guidance with fluorescence has been demonstrated in individual clinical trials for decades, but the scientific and commercial conditions exist today for a dramatic increase in clinical value. In the past decade, increased use of indocyanine green based visualization of vascular flow, biliary function, and tissue perfusion has spawned a robust growth in commercial systems that have near-infrared emission imaging and video display capabilities. This recent history combined with major preclinical innovations in fluorescent-labeled molecular probes, has the potential for a shift in surgical practice toward resection guidance based upon molecular information in addition to conventional visual and palpable cues. Most surgical subspecialties already have treatment management decisions partially based upon the immunohistochemical phenotype of the cancer, as assessed from molecular pathology of the biopsy tissue. This phenotyping can inform the surgical resection process by spatial mapping of these features. Further integration of the diagnostic and therapeutic value of tumor metabolism sensing molecules or immune binding agents directly into the surgical process can help this field mature. Maximal value to the patient would come from identifying the spatial patterns of molecular expression in vivo that are well known to exist. However, as each molecular agent is advanced into trials, the performance of the imaging system can have a critical impact on the success. For example, use of pre-existing commercial imaging systems are not well suited to image receptor targeted fluorophores because of the lower concentrations expected, requiring orders of magnitude more sensitivity. Additionally the imaging system needs the appropriate dynamic range and image processing features to view molecular probes or therapeutics that may have nonspecific uptake or pharmacokinetic issues which lead to limitations in contrast. Imaging systems need to be chosen based upon objective performance criteria, and issues around calibration, validation, and interpretation need to be established before a clinical trial starts. Finally, as early phase trials become more established, the costs associated with failures can be crippling to the field, and so judicious use of phase 0 trials with microdose levels of agents is one viable paradigm to help the field advance, but this places high sensitivity requirements on the imaging systems used. Molecular-guided surgery has truly transformative potential, and several key challenges are outlined here with the goal of seeing efficient advancement with ideal choices. The focus of this vision 20/20 paper is on the technological aspects that are needed to be paired with these agents

The automated Elecsys®-Assay for measurement of sFlt1, PlGF and the ratio sFlt1/PlGF in the diagnosis of hypertensive pregnancy disorders

Einleitung: In Vorarbeiten konnte die Bedeutung der automatisierten Messung von dem angiogenen Faktor PlGF (placental growth factor) und seinem antiangiogenen Gegenspieler sFlt1 (soluble fms-like tyrosine kinase 1) in der Diagnose der Präeklampsie (PE) aufgezeigt werden. Ziel der vorliegenden Studie war es, die Messung der einzelnen Parameter sFlt1 und PlGF dem Quotienten (sFlt1/PlGF) in der Differentialdiagnostik hypertensiver Schwangerschaftserkrankungen gegenüber zu stellen. Methodik: 64 Frauen mit PE/HELLP, 16 Frauen mit schwangerschaftsinduziertem Hypertonus (SIH), 17 Frauen mit Gestationsproteinurie (GP), 2 Frauen mit chronischem Hypertonus (cHT) und 184 Kontrollen wurden untersucht. Zur Differenzierung der PE/HELLP wurde zwischen milder PE (mPE; n = 31), schwerer PE (sPE; n = 20), Propf-PE (pPE; n = 7) und HELLP-Syndrom (n = 6) sowie zwischen früh (frPE, n = 24) und spät einsetzender PE (spPE, n = 40) unterschieden. Die Bestimmung von sFlt1 und PlGF erfolgte im Serum mittels des automatisierten Elecsys®-ELISAs (engl., enzyme linked immunosorbant assay) von Roche Diagnostics (Penzberg, Deutschland). Ergebnisse: Frauen mit PE/HELLP zeigten höhere Werte für sFlt1 und sFlt1/PlGF bzw. niedrigere Werte für PlGF vs. Kontrollen (10888 ± 878 vs. 2685 ± 138; 277 ± 39 vs. 18 ± 3 und 68 ± 6 vs. 496 ± 45, p < 0,001). Die ROC- Analyse ergab die höchste diagnostische Genauigkeit für sFlt1/PlGF (AUC 96 % vs. sFlt1 92 %; PlGF 92 %). Frauen mit pPE, mPE, sPE und HELLP zeigten signifikant höhere sFlt1/PlGF als Kontrollen (203 ± 110; 137 ± 27; 497 ± 91 und 254 ± 72 vs. 18 ± 3, jeweils p < 0,001); AUC der ROC-Kurven: 93 %, 94 %, 99 % und 98 %. Frauen mit SIH und GP unterschieden sich signifikant von Kontrollen (p ≤ 0,031), Frauen mit mPE (p ≤ 0,044), sPE (p < 0,001) und HELLP (p ≤ 0,046). Frauen mit cHT unterschieden sich signifikant von mPE, sPE und HELLP (p ≤ 0,046), nicht jedoch von Kontrollen und pPE. Frauen mit frPE und spPE zeigten signifikant erhöhte sFlt1/PlGF vs. Kontrollen (497 ± 82 vs. 12 ± 3, p < 0,001 und 131 ± 15 vs. 29 ± 5, p < 0,001), AUC der ROC-Kurven: frPE: AUC 99 % vs. sFlt1 98 %; PlGF 97 %; spPE: 91 % vs. sFlt1 82 %; PlGF 88 %. Ein Cutoff-Wert von 70 für sFlt1/PlGF ergab eine Spezifität von 94 % und eine Sensitivität von 78 % (PE/HELLP vs. Kontrollen); bei sPE und HELLP vs. Kontrollen bei gleicher Spezifität eine Sensitivität von 100 %. Schlussfolgerung: Die Bestimmung von sFlt1/PlGF durch automatisierte Messung ist vor allem für schwerwiegende Formen der PE ein zuverlässiges Mittel zur Differentialdiagnose und kann als zusätzliche, schnell zugreifbare Information das klinische Management direkt beeinflussen.Introduction: Previous works could show the importance of automatic measurement of the angiogenic factor PlGF (placental growth factor) and its antiangiogenic opponent sFlt1 (soluble fms-like tyrosine kinase 1) in the diagnosis of preeclampsia (PE). Aim of the current study was to compare automatic measurement of the single markers sFlt1 and PlGF versus its ratio (sFlt1/PlGF) in the differential diagnosis of hypertensive pregnancy disorders. Methods: 64 women with PE/HELLP, 16 women with pregnancy induced hypertension (PIH), 17 women with gestational proteinuria (GP), 2 women with chronic hypertension (cHT) and 184 controls were investigated. The PE/HELLP group was subdivided into mild PE (mPE; n = 31), severe PE (sPE; n = 20), superimposed PE (supPE; n = 7) and HELLP syndrome (HELLP, n = 6) as into early onset PE (eoPE, n = 24) and late onset PE (loPE, n = 40). The measurement of sFlt1 and PlGF in serum samples was performed using the automatic Elecsys® ELISA (engl., enzyme linked immunosorbant assay) of Roche Diagnostics (Penzberg, Germany). Results: Women with PE/HELLP had higher serum concentrations of sFlt1 and sFlt1/PlGF and lower concentrations of PlGF vs. controls, respectively (10888 ± 878 vs. 2685 ± 138; 277 ± 39 vs. 18 ± 3 and 68 ± 6 vs. 496 ± 45, p < 0.001 respectively). A ROC analysis revealed highest diagnostic power for sFlt1/PlGF (AUC 96 % vs. sFlt1 92 %; PlGF 92 %). Women with supPE, mPE, sPE and HELLP had significantly higher concentrations of sFlt1/PlGF vs. controls (203 ± 110; 137 ± 27; 497 ± 91 and 254 ± 72 vs. 18 ± 3, p < 0.001 respectively); AUC of ROC analysis: 93 %, 94 %, 99 % and 98 %, respectively. Women with PIH and GP differed significantly from controls (p ≤ 0.031), women with mPE (p ≤ 0.044), sPE (p < 0.001) and HELLP (p ≤ 0.046) but not from supPE. Women with cHT differed significantly from mPE, sPE and HELLP (p ≤ 0.046), but not from controls and supPE. Women with eoPE and loPE had significantly higher concentrations of sFlt1/PlGF vs. controls (497 ± 82 vs. 12 ± 3, p < 0.001 and 131 ± 15 vs. 29 ± 5, p < 0.001 respectively), AUC of ROC analysis: eoPE: ratio 99 % vs. sFlt1 98 %; PlGF 97 %; loPE: ratio 91 % vs. sFlt1 82 %; PlGF 88 %. A cutoff of 70 for sFlt1/PlGF resulted in a specificity of 94 % and sensitivity of 78 % (PE/HELLP vs. controls); in sPE and HELLP vs. controls in a specificity of 94 % and sensitivity of 100 %, respectively. Conclusion: Determination of sFlt1/PlGF by automatic measurement constitutes a reliable tool in differential diagnosis of hypertensive pregnancy disorders, especially in severe forms and may directly influence clinical management by additive and quickly avaible information

Oxidation, Coordination, and Nickel-Mediated Deconstruction of a Highly Electron-Rich Diboron Analogue of 1,3,5-Hexatriene

The reductive coupling of an N-heterocyclic carbene (NHC) stabilized (dibromo)vinylborane yields a 1,2-divinyl- diborene, which, although isoelectronic to a 1,3,5-triene, displays no extended p conjugation because of twisting of the C$_2$B$_2$C$_2$ chain. While this divinyldiborene coordinates to copper(I) and platinum(0) in an η$^2$-B$_2$ and η$^4$-C$_2$B$_2$ fashion, respectively, it undergoes a complex rearrangement to an η$^4$-1,3-diborete upon complexation with nickel(0)

Isolation of diborenes and their 90°-twisted diradical congeners

Molecules containing multiple bonds between atoms—most often in the form of olefins—are ubiquitous in nature, commerce, and science, and as such have a huge impact on everyday life. Given their prominence, over the last few decades, frequent attempts have been made to perturb the structure and reactivity of multiply-bound species through bending and twisting. However, only modest success has been achieved in the quest to completely twist double bonds in order to homolytically cleave the associated π bond. Here, we present the isolation of double-bond-containing species based on boron, as well as their fully twisted diradical congeners, by the incorporation of attached groups with different electronic properties. The compounds comprise a structurally authenticated set of diamagnetic multiply-bound and diradical singly-bound congeners of the same class of compound

Oxidation, Coordination, and Nickel‐Mediated Deconstruction of a Highly Electron‐Rich Diboron Analogue of 1,3,5‐Hexatriene

The reductive coupling of an N-heterocyclic carbene (NHC) stabilized (dibromo)vinylborane yields a 1,2-divinyl- diborene, which, although isoelectronic to a 1,3,5-triene, displays no extended p conjugation because of twisting of the C$_2$B$_2$C$_2$ chain. While this divinyldiborene coordinates to copper(I) and platinum(0) in an η$^2$-B$_2$ and η$^4$-C$_2$B$_2$ fashion, respectively, it undergoes a complex rearrangement to an η$^4$-1,3-diborete upon complexation with nickel(0)

Isolation of diradical products of twisted double bonds

Molecules containing multiple bonds between atoms—most often in the form of olefins—are ubiquitous in nature, commerce, and science, and as such have a huge impact on everyday life. Given their prominence, over the last few decades, frequent attempts have been made to perturb the structure and reactivity of multiply-bound species through bending and twisting. However, only modest success has been achieved in the quest to completely twist double bonds in order to homolytically cleave the associated π bond. Here, we present the isolation of double-bond-containing species based on boron, as well as their fully twisted diradical congeners, by the incorporation of attached groups with different electronic properties. The compounds comprise a structurally authenticated set of diamagnetic multiply-bound and diradical singly-bound congeners of the same class of compound