Comparing a virtual reality head-mounted display to on-screen three-dimensional visualization and two-dimensional computed tomography data for training in decision making in hepatic surgery: a randomized controlled study.

OBJECTIVE: Evaluation of the benefits of a virtual reality (VR) environment with a head-mounted display (HMD) for decision-making in liver surgery. BACKGROUND: Training in liver surgery involves appraising radiologic images and considering the patient's clinical information. Accurate assessment of 2D-tomography images is complex and requires considerable experience, and often the images are divorced from the clinical information. We present a comprehensive and interactive tool for visualizing operation planning data in a VR environment using a head-mounted-display and compare it to 3D visualization and 2D-tomography. METHODS: Ninety medical students were randomized into three groups (1:1:1 ratio). All participants analyzed three liver surgery patient cases with increasing difficulty. The cases were analyzed using 2D-tomography data (group "2D"), a 3D visualization on a 2D display (group "3D") or within a VR environment (group "VR"). The VR environment was displayed using the "Oculus Rift ™" HMD technology. Participants answered 11 questions on anatomy, tumor involvement and surgical decision-making and 18 evaluative questions (Likert scale). RESULTS: Sum of correct answers were significantly higher in the 3D (7.1 ± 1.4, p < 0.001) and VR (7.1 ± 1.4, p < 0.001) groups than the 2D group (5.4 ± 1.4) while there was no difference between 3D and VR (p = 0.987). Times to answer in the 3D (6:44 ± 02:22 min, p < 0.001) and VR (6:24 ± 02:43 min, p < 0.001) groups were significantly faster than the 2D group (09:13 ± 03:10 min) while there was no difference between 3D and VR (p = 0.419). The VR environment was evaluated as most useful for identification of anatomic anomalies, risk and target structures and for the transfer of anatomical and pathological information to the intraoperative situation in the questionnaire. CONCLUSIONS: A VR environment with 3D visualization using a HMD is useful as a surgical training tool to accurately and quickly determine liver anatomy and tumor involvement in surgery.

High-throughput screening of optimal process conditions using model predictive control.

Modern biotechnological laboratories are equipped with advanced parallel mini-bioreactor facilities that can perform sophisticated cultivation strategies (e.g., fed-batch or continuous) and generate significant amounts of measurement data. These systems require not only optimal experimental designs that find the best conditions in very large design spaces, but also algorithms that manage to operate a large number of different cultivations in parallel within a well-defined and tightly constrained operating regime. Existing advanced process control algorithms have to be tailored to tackle the specific issues of such facilities such as: a very complex biological system, constant changes in the metabolic activity and phenotypes, shifts of pH and/or temperature, and metabolic switches, to name a few. In this study we implement a model predictive control (MPC) framework to demonstrate: (1) the challenges in terms of mathematical model structure, state, and parameter estimation, and optimization under highly nonlinear and stiff dynamics in biological systems, (2) the adaptations required to enable the application of MPC in high throughput bioprocess development, and (3) the added value of MPC implementations when operating parallel mini-bioreactors aiming to maximize the biomass concentration while coping with hard constrains on the dissolved oxygen tension profile.

IMHOTEP: cross-professional evaluation of a three-dimensional virtual reality system for interactive surgical operation planning, tumor board discussion and immersive training for complex liver surgery in a head-mounted display.

BACKGROUND: Virtual reality (VR) with head-mounted displays (HMD) may improve medical training and patient care by improving display and integration of different types of information. The aim of this study was to evaluate among different healthcare professions the potential of an interactive and immersive VR environment for liver surgery that integrates all relevant patient data from different sources needed for planning and training of procedures. METHODS: 3D-models of the liver, other abdominal organs, vessels, and tumors of a sample patient with multiple hepatic masses were created. 3D-models, clinical patient data, and other imaging data were visualized in a dedicated VR environment with an HMD (IMHOTEP). Users could interact with the data using head movements and a computer mouse. Structures of interest could be selected and viewed individually or grouped. IMHOTEP was evaluated in the context of preoperative planning and training of liver surgery and for the potential of broader surgical application. A standardized questionnaire was voluntarily answered by four groups (students, nurses, resident and attending surgeons). RESULTS: In the evaluation by 158 participants (57 medical students, 35 resident surgeons, 13 attending surgeons and 53 nurses), 89.9% found the VR system agreeable to work with. Participants generally agreed that complex cases in particular could be assessed better (94.3%) and faster (84.8%) with VR than with traditional 2D display methods. The highest potential was seen in student training (87.3%), resident training (84.6%), and clinical routine use (80.3%). Least potential was seen in nursing training (54.8%). CONCLUSIONS: The present study demonstrates that using VR with HMD to integrate all available patient data for the preoperative planning of hepatic resections is a viable concept. VR with HMD promises great potential to improve medical training and operation planning and thereby to achieve improvement in patient care.

Dynamic Structural Changes and Thermodynamics in Phase Separation Processes of an Intrinsically Disordered-Ordered Protein Model.

Elastin-like proteins (ELPs) are biologically important proteins and models for intrinsically disordered proteins (IDPs) and dynamic structural transitions associated with coacervates and liquid-liquid phase transitions. However, the conformational status below and above coacervation temperature and its role in the phase separation process is still elusive. Employing matrix least-squares global Boltzmann fitting of the circular dichroism spectra of the ELPs (VPGVG)20 , (VPGVG)40 , and (VPGVG)60 , we found that coacervation occurs sharply when a certain number of repeat units has acquired ß-turn conformation (in our sequence setting a threshold of approx. 20 repeat units). The character of the differential scattering of the coacervate suspensions indicated that this fraction of ß-turn structure is still retained after polypeptide assembly. Such conformational thresholds may also have a role in other protein assembly processes with implications for the design of protein-based smart materials.

Self-Assembly Toolbox of Tailored Supramolecular Architectures Based on an Amphiphilic Protein Library.

The molecular structuring of complex architectures and the enclosure of space are essential requirements for technical and living systems. Self-assembly of supramolecular structures with desired shape, size, and stability remains challenging since it requires precise regulation of physicochemical and conformational properties of the components. Here a general platform for controlled self-assembly of tailored amphiphilic elastin-like proteins into desired supramolecular protein assemblies ranging from spherical coacervates over molecularly defined twisted fibers to stable unilamellar vesicles is introduced. The described assembly protocols efficiently yield protein membrane-based compartments (PMBC) with adjustable size, stability, and net surface charge. PMBCs demonstrate membrane fusion and phase separation behavior and are able to encapsulate structurally and chemically diverse cargo molecules ranging from small molecules to naturally folded proteins. The ability to engineer tailored supramolecular architectures with defined fusion behavior, tunable properties, and encapsulated cargo paves the road for novel drug delivery systems, the design of artificial cells, and confined catalytic nanofactories.

Minimalist Protocell Design: A Molecular System Based Solely on Proteins that Form Dynamic Vesicular Membranes Embedding Enzymatic Functions.

Life in its molecular context is characterized by the challenge of orchestrating structure, energy and information processes through compartmentalization and chemical transformations amenable to mimicry of protocell models. Here we present an alternative protocell model incorporating dynamic membranes based on amphiphilic elastin-like proteins (ELPs) rather than phospholipids. For the first time we demonstrate the feasibility of combining vesicular membrane formation and biocatalytic activity with molecular entities of a single class: proteins. The presented self-assembled protein-membrane-based compartments (PMBCs) accommodate either an anabolic reaction, based on free DNA ligase as an example of information transformation processes, or a catabolic process. We present a catabolic process based on a single molecular entity combining an amphiphilic protein with tobacco etch virus (TEV) protease as part of the enclosure of a reaction space and facilitating selective catalytic transformations. Combining compartmentalization and biocatalytic activity by utilizing an amphiphilic molecular building block with and without enzyme functionalization enables new strategies in bottom-up synthetic biology, regenerative medicine, pharmaceutical science and biotechnology.

Prebiotic Protocell Model Based on Dynamic Protein Membranes Accommodating Anabolic Reactions.

The nature of the first prebiotic compartments and their possible minimal molecular composition is of great importance in the origin of life scenarios. Current protocell model membranes are proposed to be lipid-based. This paradigm has several shortcomings such as limited membrane stability of monoacyl lipid-based membranes (e.g., fatty acids), missing pathways to synthesize protocell membrane components (e.g., phospholipids) under early earth conditions, and the requirement for different classes of molecules for the formation of compartments and the catalysis of reactions. Amino acids on the other hand are known to arise and persist with remarkable abundance under early earth conditions since the fundamental Miller-Urey experiments. They were also postulated early to form protocellular structures, for example, proteinoid capsules. Here, we present a protocell model constituted by membranes assembled from amphiphilic proteins based on prebiotic amino acids. Self-assembled dynamic protein membrane-based compartments (PMBCs) are impressively stable and compatible with prevalent cellular membrane constituents forming protein-only or protein-lipid hybrid membranes. They can embed processes essential for extant living cells, such as enclosure of molecules, membrane fusion, phase separation, and complex biosynthetic elements from modern cells demonstrating "upward" compatibility. Our findings suggest that prebiotic PMBCs represent a new type of protocell as a possible ancestor of current lipid-based cells. The presented prebiotic PMBC model can be used to design artificial cells, important for the study of structural, catalytic, and evolutionary pathways related to the emergence of life.

Structure and assembly of the mouse ASC inflammasome by combined NMR spectroscopy and cryo-electron microscopy.

Inflammasomes are multiprotein complexes that control the innate immune response by activating caspase-1, thus promoting the secretion of cytokines in response to invading pathogens and endogenous triggers. Assembly of inflammasomes is induced by activation of a receptor protein. Many inflammasome receptors require the adapter protein ASC [apoptosis-associated speck-like protein containing a caspase-recruitment domain (CARD)], which consists of two domains, the N-terminal pyrin domain (PYD) and the C-terminal CARD. Upon activation, ASC forms large oligomeric filaments, which facilitate procaspase-1 recruitment. Here, we characterize the structure and filament formation of mouse ASC in vitro at atomic resolution. Information from cryo-electron microscopy and solid-state NMR spectroscopy is combined in a single structure calculation to obtain the atomic-resolution structure of the ASC filament. Perturbations of NMR resonances upon filament formation monitor the specific binding interfaces of ASC-PYD association. Importantly, NMR experiments show the rigidity of the PYD forming the core of the filament as well as the high mobility of the CARD relative to this core. The findings are validated by structure-based mutagenesis experiments in cultured macrophages. The 3D structure of the mouse ASC-PYD filament is highly similar to the recently determined human ASC-PYD filament, suggesting evolutionary conservation of ASC-dependent inflammasome mechanisms.

Immobilization and high platelet count are associated with thromboembolic complications in heparin-induced thrombocytopenia.

PURPOSE: Immune-mediated heparin-induced thrombocytopenia (HIT type II, HIT) is a potentially serious adverse drug reaction characterized by an increased risk of venous and arterial thrombosis. This study aimed to identify risk factors associated with the development of these complications. METHODS: Our study cohort included patients with HIT assembled in our pharmacovigilance center by reports from 51 collaborating hospitals in Berlin, Germany. To identify risk factors for thromboembolic complications, patients with thromboembolic events (cases) were compared to those without thromboembolic events (controls) in a case-control design. We applied univariable and multivariable logistic regression analysis to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) for potential risk factors of thromboembolic complications. RESULTS: Our cohort comprised 209 HIT patients. Of those, 53 developed thromboembolic complications. Most HIT patients received heparin for medical indications (42.1%) or in the context of cardiovascular surgery (40.2%). Of the 78 thromboembolic complications, 49 (63%) and 29 (37%) were observed in the venous and arterial vascular bed, respectively. The main locations were deep vein thrombosis (39.7%), pulmonary embolism (16.7%), and limb artery thrombosis (16.7%). In multivariable analysis, immobilization prior to HIT (OR 4.6, 95% CI 1.2-18.0; P = .026) and higher platelet counts before initiation of heparin therapy (OR 1.004, 95% CI 1.000-1.008; P = .046) were independently associated with the occurrence of thromboembolic events. CONCLUSIONS: Immobilization and a high platelet count (with a low effect size) are additional risk factors of thromboembolic complications in the course of HIT.

Designer amphiphilic proteins as building blocks for the intracellular formation of organelle-like compartments.

Nanoscale biological materials formed by the assembly of defined block-domain proteins control the formation of cellular compartments such as organelles. Here, we introduce an approach to intentionally 'program' the de novo synthesis and self-assembly of genetically encoded amphiphilic proteins to form cellular compartments, or organelles, in Escherichia coli. These proteins serve as building blocks for the formation of artificial compartments in vivo in a similar way to lipid-based organelles. We investigated the formation of these organelles using epifluorescence microscopy, total internal reflection fluorescence microscopy and transmission electron microscopy. The in vivo modification of these protein-based de novo organelles, by means of site-specific incorporation of unnatural amino acids, allows the introduction of artificial chemical functionalities. Co-localization of membrane proteins results in the formation of functionalized artificial organelles combining artificial and natural cellular function. Adding these protein structures to the cellular machinery may have consequences in nanobiotechnology, synthetic biology and materials science, including the constitution of artificial cells and bio-based metamaterials.

Metamizole-induced agranulocytosis revisited: results from the prospective Berlin Case-Control Surveillance Study.

PURPOSE: Treatment with metamizole (dipyrone) has steadily increased in Germany over the last decade. The consequences of this increase for metamizole-induced agranulocytosis (MIA) are unclear. The present study addressed this topic using data from the Berlin Case-Control Surveillance Study. METHODS: Adult patients (≥18 years of age) with acute nonchemotherapy-induced agranulocytosis were identified by active surveillance in all 51 Berlin hospitals between 2000 and 2010. Cases related to metamizole were ascertained applying the drug causality criteria of the World Health Organization. The incidence rate of MIA was calculated and standardised by age and sex based on the German standard population in 2010. RESULTS: Twenty-six MIA cases out of 88 (30 %) patients with validated agranulocytosis were ascertained. The incidence of MIA was 0.96 (95 % confidence interval (CI) 0.95-0.97) cases per million per year. The median age of MIA cases was 50 years (quartile (Q)1 31 years; Q3 68 years) and 19 (73 %) of them were women. In 17 (65 %) cases, neutrophil granulocytes dropped below the value of 0.1 × 10(9) cells/L with three patients suffering from sepsis. Headache and postoperative pain were the most frequent indications for metamizole in outpatients (n = 16) and inpatients (n = 10), respectively. The median treatment duration was 6 days (Q1 4 days; Q3 19 days). CONCLUSIONS: MIA persists as a severe condition in current pharmacotherapy. The continuous increase of metamizole applications should be critically assessed, especially in regard to indications in the outpatient setting and with respect to metamizole treatment duration.

A Single Nucleotide Polymorphism near the CYP17A1 Gene Is Associated with Left Ventricular Mass in Hypertensive Patients under Pharmacotherapy.

Cytochrome P450 17A1 (CYP17A1) catalyses the formation and metabolism of steroid hormones. They are involved in blood pressure (BP) regulation and in the pathogenesis of left ventricular hypertrophy. Therefore, altered function of CYP17A1 due to genetic variants may influence BP and left ventricular mass. Notably, genome wide association studies supported the role of this enzyme in BP control. Against this background, we investigated associations between single nucleotide polymorphisms (SNPs) in or nearby the CYP17A1 gene with BP and left ventricular mass in patients with arterial hypertension and associated cardiovascular organ damage treated according to guidelines. Patients (n = 1007, mean age 58.0 ± 9.8 years, 83% men) with arterial hypertension and cardiac left ventricular ejection fraction (LVEF) ≥ 40% were enrolled in the study. Cardiac parameters of left ventricular mass, geometry and function were determined by echocardiography. The cohort comprised patients with coronary heart disease (n = 823; 81.7%) and myocardial infarction (n = 545; 54.1%) with a mean LVEF of 59.9% ± 9.3%. The mean left ventricular mass index (LVMI) was 52.1 ± 21.2 g/m2.7 and 485 (48.2%) patients had left ventricular hypertrophy. There was no significant association of any investigated SNP (rs619824, rs743572, rs1004467, rs11191548, rs17115100) with mean 24 h systolic or diastolic BP. However, carriers of the rs11191548 C allele demonstrated a 7% increase in LVMI (95% CI: 1%-12%, p = 0.017) compared to non-carriers. The CYP17A1 polymorphism rs11191548 demonstrated a significant association with LVMI in patients with arterial hypertension and preserved LVEF. Thus, CYP17A1 may contribute to cardiac hypertrophy in this clinical condition.

Atomic-resolution three-dimensional structure of amyloid ß fibrils bearing the Osaka mutation.

Despite its central importance for understanding the molecular basis of Alzheimer's disease (AD), high-resolution structural information on amyloid ß-peptide (Aß) fibrils, which are intimately linked with AD, is scarce. We report an atomic-resolution fibril structure of the Aß1-40 peptide with the Osaka mutation (E22Δ), associated with early-onset AD. The structure, which differs substantially from all previously proposed models, is based on a large number of unambiguous intra- and intermolecular solid-state NMR distance restraints.

Drug-induced agranulocytosis in the Berlin case-control surveillance study.

PURPOSE: Drug-induced agranulocytosis (DIAG) is a rare but serious adverse drug reaction. The Berlin Case-Control Surveillance Study (FAKOS) aimed to identify pharmaceuticals with an increased risk for this condition. METHODS: Adult patients with acute non-chemotherapy-induced agranulocytosis, developed in hospital or in the outpatient setting, were ascertained by active surveillance in all 51 Berlin hospitals between the years 2000 and 2010. Applying the criteria of the World Health Organization, a standardized drug causality assessment was conducted for each agranulocytosis patient to determine possible drug aetiology. Drug risks were quantified in a case-control design with unconditional logistic regression analysis. RESULTS: Sixty-three out of 88 validated cases of agranulocytosis were identified as being at least probably drug-related. Drug causality assessment resulted in 36 pharmaceuticals with a certain or probable relationship to agranulocytosis. Drugs involved in ≥ 3 cases with a probable or certain causality were metamizole (dipyrone) (N = 10), clozapine (N = 6), sulfasalazine (N = 5), thiamazole (N = 5), and carbamazepine (N = 3). In case-control analysis, six drugs were identified with significant odds ratios for DIAG. The highest odds ratios were observed for clozapine, sulfasalazine, and thiamazole. CONCLUSIONS: Our findings are generally in agreement with those of earlier case-control studies. The spectrum of drugs causing acute agranulocytosis has not changed considerably over recent years, despite many newly marketed drugs. Evidence for induction of agranulocytosis by some new pharmaceuticals is supported.

Influence of a neighbouring Cu centre on electro- and photocatalytic CO2 reduction by Fe-Mabiq.

Electrocatalytic and photocatalytic CO2 reduction by a heterobimetallic Cu/Fe-Mabiq complex were examined and compared to the monometallic [Fe(Mabiq)]+. The neighbouring Cu-Xantphos unit leads to marked changes in the electrocatalytic mechanism and enhanced photocatalytic performance.

Correction: Influence of a neighbouring Cu centre on electro- and photocatalytic CO2 reduction by Fe-Mabiq.

Correction for 'Influence of a neighbouring Cu centre on electro- and photocatalytic CO2 reduction by Fe-Mabiq' by Kerstin Rickmeyer et al., Chem. Commun., 2024, 60, 819-822, https://doi.org/10.1039/D3CC04777F.

Immunomodulation Using BMP-7 and IL-10 to Enhance the Mineralization Capacity of Bone Progenitor Cells in a Fracture Hematoma-Like Environment.

Following biomaterial implantation, a failure to resolve inflammation during the formation of a fracture hematoma can significantly limit the biomaterial's ability to facilitate bone regeneration. This study aims to combine the immunomodulatory and osteogenic effects of BMP-7 and IL-10 with the regenerative capacity of collagen-hydroxyapatite (CHA) scaffolds to enhance in vitro mineralization in a hematoma-like environment. Incubation of CHA scaffolds with human whole blood leads to rapid adsorption of fibrinogen, significant stiffening of the scaffold, and the formation of a hematoma-like environment characterized by a limited capacity to support the infiltration of human bone progenitor cells, a significant upregulation of inflammatory cytokines and acute phase proteins, and significantly reduced osteoconductivity. CHA scaffolds functionalized with BMP-7 and IL-10 significantly downregulate the production of key inflammatory cytokines, including IL-6, IL-8, and leptin, creating a more permissive environment for mineralization, ultimately enhancing the biomaterial's osteoconductivity. In conclusion, targeting the onset of inflammation in the early phase of bone healing using BMP-7 and IL-10 functionalized CHA scaffolds is a promising approach to effectively downregulate inflammatory processes, while fostering a more permissive environment for bone regeneration.

Automated solid-state NMR resonance assignment of protein microcrystals and amyloids.

Solid-state NMR is an emerging structure determination technique for crystalline and non-crystalline protein assemblies, e.g., amyloids. Resonance assignment constitutes the first and often very time-consuming step to a structure. We present ssFLYA, a generally applicable algorithm for automatic assignment of protein solid-state NMR spectra. Application to microcrystals of ubiquitin and the Ure2 prion C-terminal domain, as well as amyloids of HET-s(218-289) and α-synuclein yielded 88-97 % correctness for the backbone and side-chain assignments that are classified as self-consistent by the algorithm, and 77-90 % correctness if also assignments classified as tentative by the algorithm are included.

Programming protein phase-separation employing a modular library of intrinsically disordered precision block copolymer-like proteins creating dynamic cytoplasmatic compartmentalization.

The control of supramolecular complexes in living systems at the molecular level is an important goal in life-sciences. Spatiotemporal organization of molecular distribution & flow of such complexes are essential physicochemical processes in living cells and important for pharmaceutical processes. Membraneless organelles (MO) found in eukaryotic cells, formed by liquid-liquid phase-separation (LLPS) of intrinsically disordered proteins (IDPs) control and adjust intracellular organization. Artificially designed compartments based on LLPS open up a novel pathway to control chemical flux and partition in vitro and in vivo. We designed a library of chemically precisely defined block copolymer-like proteins based on elastin-like proteins (ELPs) with defined charge distribution and type, as well as polar and hydrophobic block domains. This enables the programmability of physicochemical properties and to control adjustable LLPS in vivo attaining control over intracellular partitioning and flux as role model for in vitro and in vivo applications. Tailor-made ELP-like block copolymer proteins exhibiting IDP-behavior enable LLPS formation in vitro and in vivo allowing the assembly of membrane-based and membraneless superstructures via protein phase-separation in E. coli. Subsequently, we demonstrate the responsiveness of protein phase-separated spaces (PPSSs) to environmental physicochemical triggers and their selective, charge-dependent and switchable interaction with DNA or extrinsic and intrinsic molecules enabling their selective shuttling across semipermeable phase boundaries including (cell)membranes. This paves the road for adjustable artificial PPSS-based storage and reaction spaces and the specific transport across phase boundaries for applications in pharmacy and synthetic biology.

4D solid-state NMR for protein structure determination.

Solid-state NMR offers the chance to extend structural studies to proteins that are otherwise difficult to study at atomic resolution, such as protein fibrils, membrane proteins or poorly diffracting crystals. As two-dimensional spatial correlation NMR spectra of proteins suffer from severe resonance overlap, we analyze in this perspective article the potential of higher-dimensional (3D and 4D) proton-detected experiments, which have an increased number of identifiable and assignable distance restraints for solid-state structural studies. We discuss practical considerations for the NMR measurements and the preparation of suitable protein samples and show results of structure calculations from 4D solid-state NMR spectra.