Leveraging the Value of CDISC SEND Data Sets for Cross-Study Analysis: Incidence of Microscopic Findings in Control Animals.

Implementation of the Clinical Data Interchange Standards Consortium (CDISC)'s Standard for Exchange of Nonclinical Data (SEND) by the United States Food and Drug Administration Center for Drug Evaluation and Research (US FDA CDER) has created large quantities of SEND data sets and a tremendous opportunity to apply large-scale data analytic approaches. To fully realize this opportunity, differences in SEND implementation that impair the ability to conduct cross-study analysis must be addressed. In this manuscript, a prototypical question regarding historical control data (see Table of Contents graphic) was used to identify areas for SEND harmonization and to develop algorithmic strategies for nonclinical cross-study analysis within a variety of databases. FDA CDER's repository of >1800 sponsor-submitted studies in SEND format was queried using the statistical programming language R to gain insight into how the CDISC SEND Implementation Guides are being applied across the industry. For each component needed to answer the question (defined as "query block"), the frequency of data population was determined and ranged from 6 to 99%. For fields populated <90% and/or that did not have Controlled Terminology, data extraction methods such as data transformation and script development were evaluated. Data extraction was successful for fields such as phase of study, negative controls, and histopathology using scripts. Calculations to assess accuracy of data extraction indicated a high confidence in most query block searches. Some fields such as vehicle name, animal supplier name, and test facility name are not amenable to accurate data extraction through script development alone and require additional harmonization to confidently extract data. Harmonization proposals are discussed in this manuscript. Implementation of these proposals will allow stakeholders to capitalize on the opportunity presented by SEND data sets to increase the efficiency and productivity of nonclinical drug development, allowing the most promising drug candidates to proceed through development.

The Incidence of Catheter Tract Hemorrhage and Catheter Placement Accuracy in the CLEAR III Trial.

BACKGROUND: Incidence of catheter tract hemorrhage (CTH) after initial ventriculostomy placement ranges from 10 to 34%. We investigated CTH incidence in the Clot Lysis: Evaluation of Accelerated Resolution of Intraventricular Hemorrhage Phase III trial. METHODS: Prospective observational analysis of 1000 computer tomography (CT) scans from all 500 patients enrolled in the trial. All catheters were evaluated on first CT post-placement and on last CT prior to randomization for placement location and CTH size, location, and severity. Clinical variables were assessed for association with CTH with multivariable logistic regression. RESULTS: Of 563 catheters, CTH was detected in 14 and 21% of patients on first and last CT (median 3.7 and 43.4 h after catheter placement, respectively). All, but one were asymptomatic. Majority of CTH (86%) occurred within 24 h after placement, were located within 1 cm of the skull, and had at least one diameter > 5 mm. Most catheters (71%) terminated in the third or lateral ventricle ipsilateral to insertion site. Factors significantly associated with CTH were pre-admission use of antiplatelet drugs, accuracy of catheter placement, non-operating room catheter placement, Asian race, and intraventricular hemorrhage expansion. CONCLUSIONS: CTH incidence on initial catheter placement and during stabilization was relatively low, despite emergent placement in a high-risk population. Catheter placement accuracy was similar or better than convenience samples from the published literature. Decreasing risk of CTH may be achieved with attention to catheter placement accuracy and placement in the operating room. Antiplatelet agent use was an independent risk factor for CTH.

Addition of Si-H and B-H bonds and redox reactivity involving low-coordinate nitrido-vanadium complexes.

In this study we enumerate the reactivity for two molecular vanadium nitrido complexes of [(nacnac)V≡N(X)] formulation [nacnac = (Ar)NC(Me)CHC(Me)(Ar)(-), Ar = 2,6-(CHMe2)2C6H3); X(-) = OAr (1) and N(4-Me-C6H4)2 (Ntolyl2) (2)]. Density functional theory calculations and reactivity studies indicate the nitride motif to have nucleophilic character, but where the nitrogen atom can serve as a conduit for electron transfer, thus allowing the reduction of the vanadium(V) metal ion with concurrent oxidation of the incoming substrate. Silane, H2SiPh2, readily converts the nitride ligand in 1 into a primary silyl-amide functionality with concomitant two-electron reduction at the vanadium center to form the complex [(nacnac)V{N(H)SiHPh2}(OAr)] (3). Likewise, addition of the B-H bond in pinacolborane to the nitride moiety in 2 results in formation of the boryl-amide complex [(nacnac)V{N(H)B(pinacol)}(Ntolyl2)] (4). In addition to spectroscopic data, complexes 3 and 4 were also elucidated structurally by single-crystal X-ray diffraction analysis. One-electron reduction of 1 with 0.5% Na/Hg on a preparative scale allowed for the isolation and structural determination of an asymmetric bimolecular nitride radical anion complex having formula [Na]2[(nacnac)V(N)(OAr)]2 (5), in addition to room-temperature solution X-band electron paramagnetic resonance spectroscopic studies.

A nitrido salt reagent of titanium.

Deprotonation of the parent titanium imido ((tBu)nacnac)Ti≡NH(Ntolyl2) ((tBu)nacnac(-) = [ArNC(t)Bu]2CH; Ar = 2,6-(i)Pr2C6H3) with KCH2Ph forms a rare example of a molecular titanium nitride as a dimer, {[K][((tBu)nacnac)Ti≡N(Ntolyl2)]}2. From the parent imido or nitride salt, the corresponding aluminylimido-etherate adduct, ((tBu)nacnac)Ti≡N[AlMe2(OEt2)](Ntolyl2), can be isolated and structurally characterized. The parent imido is also a source for the related borylimido, ((tBu)nacnac)Ti═NBEt2(Ntolyl2).

A four-coordinate thionitrosyl complex of vanadium.

Addition of elemental sulfur to the vanadium nitride [(nacnac)V≡N(OAr)] forms the first thionitrosyl complex of vanadium, [(nacnac)V(NS)(OAr)]. Single crystal X-Ray diffraction studies and DFT calculations reveal an almost linear thionitrosyl ligand resulting from an extended π-resonance across the VNS moiety.

A planar three-coordinate vanadium(II) complex and the study of terminal vanadium nitrides from N2: a kinetic or thermodynamic impediment to N-N bond cleavage?

We report the first mononuclear three-coordinate vanadium(II) complex [(nacnac)V(ODiiP)] and its activation of N2 to form an end-on bridging dinitrogen complex with a topologically linear V(III)N2V(III) core and where each vanadium center antiferromagnetically couples to give a ground state singlet with an accessible triplet state as inferred by HFEPR spectroscopy. In addition to investigating the conversion of N2 to the terminal nitride (as well as the microscopic reverse process), we discuss its similarities and contrasts to the isovalent d(3) system, [Mo(N[(t)Bu]Ar)3], and the S = 1 system [(Ar[(t)Bu]N)3Mo]2(µ2-η(1):η(1)-N2).