Determination of procoagulant activity in human normal immunoglobulin preparations for therapeutic use by FXIa chromogenic assay: Evaluation of test kit sensitivity, reference standard performance and product formulation effects on the FXIa assay.

In 2010, the reporting of thrombotic adverse events for one subcutaneous and certain intravenous immunoglobulins (IGs) raised some concerns. In Europe, regulatory bodies rapidly revised compendial specifications for therapeutic IGs to ensure they do not exhibit thrombogenic (procoagulant) activity (PCA). At the global level, a working group (GWG) was launched with the aim of assessing PCA measurement methods and limits, considering results obtained by human IG manufacturers during in-process controls. The GWG created three dedicated subgroups to investigate the FXIa chromogenic assay, the non-activated partial thromboplastin time (NAPTT) test and the thrombin generation assay (TGA). The European Directorate for the Quality of Medicines & HealthCare (EDQM) was responsible for co-ordinating the subgroup in charge of evaluating the FXIa chromogenic assay in a study that assessed the sensitivity and robustness of two commercial chromogenic FXIa test kits. The impact of IG product formulation on FXIa recovery and the suitability of PCA-containing IG products as potential reference standards/controls were also assessed. IG materials representative of marketed products were provided to four laboratories for a study that was carried out in two steps: 1) two chromogenic FXIa test kit manufacturers assessed the performance and determined optimal test conditions by their respective methods, 2) two OMCLs studied both kits using an optimised study design. Regarding sensitivity, the study results identified suitable dose-response intervals and limits with both chromogenic FXIa test kits. This allowed the establishment of dilution ranges for optimal detection of FXIa/PCA in 5 % and 10 % IG products in the range of 1-6 mIU/mL. However, careful optimisation of the sample dilutions was required (notably to avoid potential matrix effects) and the choice of the mode of data acquisition (kinetic or end-point method) contributed to sensitivity in routine use. Importantly, the composition of IG products was of minor concern for FXIa determination with both test kits. Potential reference materials evaluated in the study behaved as expected and could be useful should a separate reference standard to the FXIa WHO IS be deemed necessary in future.

Experimental capabilities for liquid jet samples at sub-MHz rates at the FXE Instrument at European XFEL.

The Femtosecond X-ray Experiments (FXE) instrument at the European X-ray Free-Electron Laser (EuXFEL) provides an optimized platform for investigations of ultrafast physical, chemical and biological processes. It operates in the energy range 4.7-20 keV accommodating flexible and versatile environments for a wide range of samples using diverse ultrafast X-ray spectroscopic, scattering and diffraction techniques. FXE is particularly suitable for experiments taking advantage of the sub-MHz repetition rates provided by the EuXFEL. In this paper a dedicated setup for studies on ultrafast biological and chemical dynamics in solution phase at sub-MHz rates at FXE is presented. Particular emphasis on the different liquid jet sample delivery options and their performance is given. Our portfolio of high-speed jets compatible with sub-MHz experiments includes cylindrical jets, gas dynamic virtual nozzles and flat jets. The capability to perform multi-color X-ray emission spectroscopy (XES) experiments is illustrated by a set of measurements using the dispersive X-ray spectrometer in von Hamos geometry. Static XES data collected using a multi-crystal scanning Johann-type spectrometer are also presented. A few examples of experimental results on ultrafast time-resolved X-ray emission spectroscopy and wide-angle X-ray scattering at sub-MHz pulse repetition rates are given.

Inception of electronic damage of matter by photon-driven post-ionization mechanisms.

"Probe-before-destroy" methodology permitted diffraction and imaging measurements of intact specimens using ultrabright but highly destructive X-ray free-electron laser (XFEL) pulses. The methodology takes advantage of XFEL pulses ultrashort duration to outrun the destructive nature of the X-rays. Atomic movement, generally on the order of >50 fs, regulates the maximum pulse duration for intact specimen measurements. In this contribution, we report the electronic structure damage of a molecule with ultrashort X-ray pulses under preservation of the atoms' positions. A detailed investigation of the X-ray induced processes revealed that X-ray absorption events in the solvent produce a significant number of solvated electrons within attosecond and femtosecond timescales that are capable of coulombic interactions with the probed molecules. The presented findings show a strong influence on the experimental spectra coming from ionization of the probed atoms' surroundings leading to electronic structure modification much faster than direct absorption of photons. This work calls for consideration of this phenomenon in cases focused on samples embedded in, e.g., solutions or in matrices, which in fact concerns most of the experimental studies.

Towards X-ray transient grating spectroscopy.

The extension of transient grating spectroscopy to the x-ray regime will create numerous opportunities, ranging from the study of thermal transport in the ballistic regime to charge, spin, and energy transfer processes with atomic spatial and femtosecond temporal resolution. Studies involving complicated split-and-delay lines have not yet been successful in achieving this goal. Here we propose a novel, simple method based on the Talbot effect for converging beams, which can easily be implemented at current x-ray free electron lasers. We validate our proposal by analyzing printed interference patterns on polymethyl methacrylate and gold samples using ∼3 keV X-ray pulses.

Femtosecond phase-transition in hard x-ray excited bismuth.

The evolution of bismuth crystal structure upon excitation of its A1g phonon has been intensely studied with short pulse optical lasers. Here we present the first-time observation of a hard x-ray induced ultrafast phase transition in a bismuth single crystal at high intensities (~1014 W/cm2). The lattice evolution was followed using a recently demonstrated x-ray single-shot probing setup. The time evolution of the (111) Bragg peak intensity showed strong dependence on the excitation fluence. After exposure to a sufficiently intense x-ray pulse, the peak intensity dropped to zero within 300 fs, i.e. faster than one oscillation period of the A1g mode at room temperature. Our analysis indicates a nonthermal origin of a lattice disordering process, and excludes interpretations based on electron-ion equilibration process, or on thermodynamic heating process leading to plasma formation.

Establishment of detection antibodies BRRs batch 5 for in vitro potency assay of hepatitis A vaccines by ELISA.

The European Pharmacopoeia (Ph. Eur.) standard ELISA method for determination of antigen content of hepatitis A vaccines (HAV) requires specific coating and detection Biological Reference Reagents (BRRs). The 4th batch of detection antibodies BRRs was established in 2017 for use in conjunction with the Ph. Eur. General Chapter 2.7.14 Assay of hepatitis A vaccine. Stocks of these BRRs were running low and therefore the European Directorate for the Quality of Medicines and HealthCare (EDQM) organised a collaborative study to qualify replacement batches. The candidate BRR antibodies batch 5 were prepared under appropriate conditions from starting materials similar to previous batches to ensure continuity. Prior to the study, a low level of detection was obtained with new batches of the HRPO-GAM provided by the established supplier, supposedly due to a manufacturing issue in the conjugation step. Several other batches procured from the same supplier were tested without any success. Consequently HRPO-GAM batches from 3 other suppliers were tested and one batch was chosen to be included as a BRR based on its suitable characteristics. During the collaborative study, the new batches of antibodies were compared to previous batches of BRRs. Results confirmed that they were suitable to be used for the intended purpose, and could be used at the same final concentrations as the previous batch, i.e. 1:500 for the primary antibody and 1:400 for the conjugated secondary antibody. A higher background OD than in previous batches was observed, so it is recommended to subtract the background from the OD values obtained in the test in order to plot the sigmoid curve and calculate the titre of test samples. Moreover it is recommended that the first dilutions used for the IS and BRP2 should be 1:2 and 1:20, respectively, in order to achieve the same ODmax as for the previous BRRs batches. The BRRs were adopted by correspondence in October 2018 by the Ph. Eur. Commission and are presented as a set containing Hepatitis A virus primary detection antibody BRR batch 5 and Conjugated secondary detection antibody BRR batch 5. They are available from the EDQM as Hepatitis A vaccine ELISA detection antibodies set BRR batch 5.

Internal medicine fellowship directors' perspectives on the quality and utility of letters conforming to residency program director letter of recommendation guidelines.

Background: In May 2017, the Alliance for Academic Internal Medicine (AAIM) published guidelines intending to standardize and improve internal medicine residency program director (PD) letters of recommendation (LORs) for fellowship applicants. Objectives: This study aimed to examine fellowship PDs impressions of the new guidelines, letter writers' adherence to the guidelines, and the impact of LORs that conformed to guidelines compared to non-standardized letters. Methods: The authors anonymously surveyed fellowship PDs from January to March 2018 to gather input about LORs submitted to their programs during the 2017 fellowship application cycle. Results: A total of 78% of survey respondents were satisfied with letters that followed the AAIM guidelines, whereas 48% of respondents were satisfied with letters that did not. Fellowship PDs felt that letters that followed the AAIM guidelines were more helpful than letters that did not, especially for differentiating between applicants from the same institution and for understanding residents' performance across the six core competency domains. Fellowship PDs provided several suggestions for residency PDs to make the LORs even more helpful. Conclusion: Fellowship PD respondents indicated that LORs that followed the new AAIM guidelines were more helpful than letters that did not.

Replacement, Reduction, Refinement - Animal welfare progress in European Pharmacopoeia monographs: activities of the European Pharmacopoeia Commission from 2007 to 2017.

Since the opening for signature of the European Convention for the Protection of Animals Used for Experimental and Other Scientific Purposes in 1986, the European Pharmacopoeia Commission and its experts have carried out a programme of work committed to Replacing, Reducing and Refining (3Rs) the use of animals for test purposes. While updates on achievements in the field of the 3Rs are regularly provided, this article summarises the activities of the Ph. Eur. Commission in this field within the last decade.

Short-wavelength free-electron laser sources and science: a review.

This review is focused on free-electron lasers (FELs) in the hard to soft x-ray regime. The aim is to provide newcomers to the area with insights into: the basic physics of FELs, the qualities of the radiation they produce, the challenges of transmitting that radiation to end users and the diversity of current scientific applications. Initial consideration is given to FEL theory in order to provide the foundation for discussion of FEL output properties and the technical challenges of short-wavelength FELs. This is followed by an overview of existing x-ray FEL facilities, future facilities and FEL frontiers. To provide a context for information in the above sections, a detailed comparison of the photon pulse characteristics of FEL sources with those of other sources of high brightness x-rays is made. A brief summary of FEL beamline design and photon diagnostics then precedes an overview of FEL scientific applications. Recent highlights are covered in sections on structural biology, atomic and molecular physics, photochemistry, non-linear spectroscopy, shock physics, solid density plasmas. A short industrial perspective is also included to emphasise potential in this area.

Editor's Choice - Subsequent Results for Arch Aneurysm Repair with Inner Branched Endografts.

OBJECTIVES: The aim was to evaluate the current results of aortic arch aneurysm repair using inner branched endografts performed in three high volume aortic endovascular centers and to compare them to the pioneering global experience with this technology. METHODS: Included patients underwent repair of aortic arch aneurysms >55 mm in diameter using inner branched endograft technology between April 2013 and November 2014. All patients were deemed unfit for open surgery. Inner branches were designed to perfuse the brachiocephalic trunk and the left common carotid artery in all cases. A left subclavian artery (LSA) revascularization was performed prior to the arch endovascular repair. Data were collected retrospectively in an electronic database. Parameters included length of procedure, fluoroscopy time, contrast volume, technical success, presence of endoleaks, early and late complications, and mortality. RESULTS: Twenty-seven patients were included in the study. Technical success was achieved in all cases. No patients died during the 30 day post-operative period. Early neurologic events included two major strokes (7.4%) and one minor stroke (3.7%). Transient spinal cord ischemia with full recovery was observed in two patients (7.4%). Four patients (14.8%) underwent early (<30 day) re-interventions; these were for an access complication, an ischemic limb and exploration of the left ventricle through a sternotomy in two patients. During follow up (median 12 months), one patient (3.7%) died from a remote thoraco-abdominal aneurysm rupture. There were three Type 2 endoleaks (11.1%). Two re-interventions (7.4%) were performed, one to treat a Type 2 endoleak and one to treat a septic false aneurysm. A significant decrease in overall mortality was observed when comparing patients from the early experience with patients from the current report. CONCLUSIONS: The early outcomes associated with this technology are favorable. Branched endografting of aortic arch aneurysms should be considered in patients unfit for open surgery.

European Pharmacopoeia biological reference preparation for poliomyelitis vaccine (inactivated): collaborative study for the establishment of batch No. 3.

Inactivated poliomyelitis vaccines are an important part of the World Health Organization (WHO) control strategy to eradicate poliomyelitis. Requirements for the quality control of poliomyelitis vaccines (inactivated) include the use of an in vitro D antigen quantification assay for potency determination on the final lot as outlined in the European Pharmacopoeia (Ph. Eur.) monograph 0214. Performance of this assay requires a reference preparation calibrated in International Units (IU). A Ph. Eur. biological reference preparation (BRP) for poliomyelitis vaccine (inactivated) calibrated in IU has been established for this purpose. Due to the dwindling stocks of batch 2 of the BRP a collaborative study was run as part of the European Directorate for the Quality of Medicines & HealthCare (EDQM) Biological Standardisation Programme to establish BRP batch 3 (BRP3). Twelve laboratories including Official Medicines Control Laboratories (OMCLs) and manufacturers participated. The candidate BRP3 (cBRP3) was from the same source and had the same characteristics as BRP batch 2 (BRP2). During the study the candidate was calibrated against the 3rd International Standard for inactivated poliomyelitis vaccine using in-house D antigen ELISA assays in line with the Ph. Eur. monograph 0214. The candidate was also compared to BRP2 to evaluate the continuity. Based on the results of the study, values of 320 DU/mL, 78 DU/mL and 288 DU/mL (D antigen units/mL) (IU) for poliovirus type 1, 2 and 3 respectively were assigned to the candidate. In June 2016, the Ph. Eur. Commission adopted the material as Ph. Eur. BRP for poliomyelitis vaccine (inactivated) batch 3.

Following the dynamics of matter with femtosecond precision using the X-ray streaking method.

X-ray Free Electron Lasers (FELs) can produce extremely intense and very short pulses, down to below 10 femtoseconds (fs). Among the key applications are ultrafast time-resolved studies of dynamics of matter by observing responses to fast excitation pulses in a pump-probe manner. Detectors with sufficient time resolution for observing these processes are not available. Therefore, such experiments typically measure a sample's full dynamics by repeating multiple pump-probe cycles at different delay times. This conventional method assumes that the sample returns to an identical or very similar state after each cycle. Here we describe a novel approach that can provide a time trace of responses following a single excitation pulse, jitter-free, with fs timing precision. We demonstrate, in an X-ray diffraction experiment, how it can be applied to the investigation of ultrafast irreversible processes.

EDQM biological reference preparation for rabies vaccine (inactivated) for veterinary use.

Rabies is a deadly zoonotic disease. Control of rabies in animals by vaccination is an important strategy to protect humans from infection and control the spread of the disease. Requirements for the quality control of rabies vaccines (inactivated) for veterinary use include an in vivo quantitative potency determination as outlined in the Ph. Eur. monograph 0451. Performance of this assay requires a reference preparation calibrated in International Units (IU). A European Pharmacopeia (Ph. Eur.) Biological Reference Preparation (BRP) for rabies vaccines (inactivated) for veterinary use, calibrated in IU, has been established for this purpose. Due to the dwindling stocks of the current batch (batch 4) of Ph. Eur. BRP for rabies vaccines (inactivated) for veterinary use, a collaborative study was run as part of the EDQM Biological Standardisation Programme to establish BRP batch 5. Ten laboratories, including Official Medicines Control Laboratories and manufacturers, participated. The candidate BRP5 was assayed against the 6(th) International Standard for rabies vaccine using the in vivo vaccination-challenge assay (monograph 0451) to assign a potency value. The candidate was also compared to BRP batch 4 to establish continuity. Taking into account the results from the comparisons a potency of 10 IU/vial was assigned and in March 2015 the Ph. Eur. Commission adopted the material as Ph. Eur. BRP for rabies vaccines (inactivated) for veterinary use batch 5. In addition to the in vivo assay 3 laboratories tested the candidate material using their in-house in vitro assays for information.

X-ray spectroscopic study of solvent effects on the ferrous and ferric hexacyanide anions.

We present an Fe Kα resonant inelastic X-ray scattering (RIXS) and X-ray emission (XES) study of ferrous and ferric hexacyanide dissolved in water and ethylene glycol. We observe that transitions below the absorption edge show that the solvent has a distinct effect on the valence electronic structure. In addition, both the RIXS and XES spectra show a stabilization of the 2p levels when dissolved in water. Using molecular dynamics simulations, we propose that this effect arises from the hydrogen-bonding interactions between the complex and nearby solvent molecules. This withdraws electron density from the ligands, stabilizing the complex but also causing a slight increase in π-backbonding.

Prospects for rapid advances in the development of new medicines for special medical needs.

Broadly speaking, the goals of the US Food and Drug Administration (FDA) special-designation programs--orphan, priority review, accelerated approval, and fast track--have been to expedite and sustain development and facilitate authorization of new medicines for unmet medical needs through so-called "push-pull" incentives. Although generally successful over time, their success has been confined to certain therapeutic areas and, within those areas, certain diseases. Times have changed. The research and development (R&D) burdens and public health urgency that acted as an impetus for the FDA to intervene more actively for certain disease areas are now broadly experienced across many disease areas. This betokens the need for the FDA to make designation and implementation decisions with a view that reaches beyond the immediate horizons of political expediency and patient advocacy to encompass the broader expanse of factors that now influence R&D decisions--global competitiveness, the needs of investors, emerging sponsors, and patient-focused drug development.

Communication: The electronic structure of matter probed with a single femtosecond hard x-ray pulse.

Physical, biological, and chemical transformations are initiated by changes in the electronic configuration of the species involved. These electronic changes occur on the timescales of attoseconds (10(-18) s) to femtoseconds (10(-15) s) and drive all subsequent electronic reorganization as the system moves to a new equilibrium or quasi-equilibrium state. The ability to detect the dynamics of these electronic changes is crucial for understanding the potential energy surfaces upon which chemical and biological reactions take place. Here, we report on the determination of the electronic structure of matter using a single self-seeded femtosecond x-ray pulse from the Linac Coherent Light Source hard x-ray free electron laser. By measuring the high energy resolution off-resonant spectrum (HEROS), we were able to obtain information about the electronic density of states with a single femtosecond x-ray pulse. We show that the unoccupied electronic states of the scattering atom may be determined on a shot-to-shot basis and that the measured spectral shape is independent of the large intensity fluctuations of the incoming x-ray beam. Moreover, we demonstrate the chemical sensitivity and single-shot capability and limitations of HEROS, which enables the technique to track the electronic structural dynamics in matter on femtosecond time scales, making it an ideal probe technique for time-resolved X-ray experiments.

Photooxidation and photoaquation of iron hexacyanide in aqueous solution: A picosecond X-ray absorption study.

We present a picosecond Fe K-edge absorption study of photoexcited ferrous and ferric hexacyanide in water under 355 and 266 nm excitation. Following 355 nm excitation, the transient spectra for the ferrous and ferric complexes exhibit a red shift of the edge reflecting an increased electron density at the Fe atom. For the former, an enhanced pre-edge transition is also observed. These observations are attributed to the aquated [Fe(CN)5OH2](3-) species, based on quantum chemical calculations which also provide structural parameters. Upon 266 nm excitation of the ferric complex, a transient reminiscent of the aquated species is observed (appearance of a pre-edge feature and red shift of the edge) but it is different from that obtained under 355 nm excitation. This points to a new reaction channel occurring through an intermediate state lying between these two excitation energies. Finally, 266 nm excitation of the ferrous species is dominated by the photooxidation channel with formation of the ferric complex as main photoproduct. However, we observe an additional minor photoproduct, which is identical to the 266 nm generated photoproduct of the ferric species, suggesting that under our experimental conditions, the pump pulse photooxidises the ferrous complex and re-excites the primary ferric photoproduct.

Solvent-induced luminescence quenching: static and time-resolved X-ray absorption spectroscopy of a copper(I) phenanthroline complex.

We present a static and picosecond X-ray absorption study at the Cu K-edge of bis(2,9-dimethyl-1,10-phenanthroline)copper(I) ([Cu(dmp)2](+); dmp = 2,9-dimethyl-1,10-phenanthroline) dissolved in acetonitrile and dichloromethane. The steady-state photoluminescence spectra in dichloromethane and acetonitrile are also presented and show a shift to longer wavelengths for the latter, which points to a stronger stabilization of the excited complex. The fine structure features of the static and transient X-ray spectra allow an unambiguous assignment of the electronic and geometric structure of the molecule in both its ground and excited (3)MLCT states. Importantly, the transient spectra are remarkably similar for both solvents, and the spectral changes can be rationalized using the optimized ground- and excited-state structures of the complex. The proposed assignment of the lifetime shortening of the excited state in donor solvents (acetonitrile) to a metal-centered exciplex is not corroborated here. Molecular dynamics simulations confirm the lack of complexation; however, in both solvents the molecules come close to the metal but undergo rapid exchange with the bulk. The shortening of the lifetime of the title complex and nine additional related complexes can be rationalized by the decrease in the (3)MLCT energy. Deviations from this trend may be explained by means of the effects of the dihedral angle between the ligand planes, the solvent, and the (3)MLCT-(1)MLCT energy gap.

A wavelet analysis for the X-ray absorption spectra of molecules.

We present a Wavelet transform analysis for the X-ray absorption spectra of molecules. In contrast to the traditionally used Fourier transform approach, this analysis yields a 2D correlation plot in both R- and k-space. As a consequence, it is possible to distinguish between different scattering pathways at the same distance from the absorbing atom and between the contributions of single and multiple scattering events, making an unambiguous assignment of the fine structure oscillations for complex systems possible. We apply this to two previously studied transition metal complexes, namely iron hexacyanide in both its ferric and ferrous form, and a rhenium diimine complex, [ReX(CO)(3)(bpy)], where X = Br, Cl, or ethyl pyridine (Etpy). Our results demonstrate the potential advantages of using this approach and they highlight the importance of multiple scattering, and specifically the focusing phenomenon to the extended X-ray absorption fine structure (EXAFS) spectra of these complexes. We also shed light on the low sensitivity of the EXAFS spectrum to the Re-X scattering pathway.

X-ray absorption spectroscopy of ground and excited rhenium-carbonyl-diimine complexes: evidence for a two-center electron transfer.

Steady-state and picosecond time-resolved X-ray absorption spectroscopy is used to study the ground and lowest triplet states of [ReX(CO)(3)(bpy)](n+), X = Etpy (n = 1), Cl, or Br (n = 0). We demonstrate that the transient spectra at both the Re L(3)- and Br K-edges show the emergence of a pre-edge feature, absent in the ground-state spectrum, which is associated with the electron hole created in the highest occupied molecular orbital following photoexcitation. Importantly, these features have the same dynamics, confirming previous predictions that the low-lying excited states of these complexes involve a two-center charge transfer from both the Re and the ligand, X. We also demonstrate that the DFT optimized ground and excited structures allow us to reproduce the experimental XANES and EXAFS spectra. The ground-state structural refinement shows that the Br atom contributes very little to the latter, whereas the Re-C-O scattering paths are dominant due to the so-called focusing effect. For the excited-state spectrum, the Re-X bond undergoes one of the largest changes but still remains a weak contribution to the photoinduced changes of the EXAFS spectrum.