Extending the IMQ Model: Deep Characterization of the Human TLR7 Response for Early Drug Development.

Imiquimod (IMQ; brand name Aldara®) is a registered topical agent that has been proven to induce local inflammation via the Toll-like receptor (TLR)7 pathway. The purpose of this study was to characterize TLR7-mediated inflammation following 7 days (168 h) of topical IMQ exposure in healthy volunteers, and to compare the effects of short exposure (48 h-72 h) with prolonged exposure (120 h-168 h). IMQ (100mg) was applied under occlusion to 5 different tape-stripped treatment sites on the back of 10 healthy participants for a maximum of 7 consecutive days.

Single-molecule structural and kinetic studies across sequence space.

At the core of molecular biology lies the intricate interplay between sequence, structure, and function. Single-molecule techniques provide in-depth dynamic insights into structure and function, but laborious assays impede functional screening of large sequence libraries. We introduce high-throughput Single-molecule Parallel Analysis for Rapid eXploration of Sequence space (SPARXS), integrating single-molecule fluorescence with next-generation sequencing.

Prerequisites for Clinical Implementation of Whole-Heart 4D-Flow MRI: A Delphi Analysis.

Whole-heart 4D-flow MRI is a valuable tool for advanced visualization and quantification of blood flow in cardiovascular imaging. Despite advantages over 2D-phase-contrast flow, clinical implementation remains only partially exploited due to many hurdles in all steps, from image acquisition, reconstruction, postprocessing and analysis, clinical embedment, reporting, legislation, and regulation to data storage. The intent of this manuscript was 1) to evaluate the extent of clinical implementation of whole-heart 4D-flow MRI, 2) to identify hurdles hampering clinical implementation, and 3) to reach consensus on requirements for clinical implementation of whole-heart 4D-flow MRI.

The shelterin component TRF2 mediates columnar stacking of human telomeric chromatin.

Telomere repeat binding factor 2 (TRF2) is an essential component of the telomeres and also plays an important role in a number of other non-telomeric processes. Detailed knowledge of the binding and interaction of TRF2 with telomeric nucleosomes is limited. Here, we study the binding of TRF2 to in vitro-reconstituted kilobasepair-long human telomeric chromatin fibres using electron microscopy, single-molecule force spectroscopy and analytical ultracentrifugation sedimentation velocity.

Reliability and accuracy of single-molecule FRET studies for characterization of structural dynamics and distances in proteins.

Single-molecule Förster-resonance energy transfer (smFRET) experiments allow the study of biomolecular structure and dynamics in vitro and in vivo. We performed an international blind study involving 19 laboratories to assess the uncertainty of FRET experiments for proteins with respect to the measured FRET efficiency histograms, determination of distances, and the detection and quantification of structural dynamics. Using two protein systems with distinct conformational changes and dynamics, we obtained an uncertainty of the FRET efficiency ≤0.

Estimated cumulative radiation exposure in patients treated for adolescent idiopathic scoliosis.

Purpose: Adolescent idiopoathic scoliosis (AIS) is a progressive spinal deformity, most often observed in female patients of pubescent age. The deformity's severity, its progression through time, its treatment and subsequent follow-up are assessed with routine radiological evaluation of the patient's full spine. This study aimed to determine the cumulative radiation exposure in average patients with AIS treated by brace or surgery throughout their treatment.

Total knee arthroplasty improves gait adaptability in osteoarthritis patients; a pilot study.

Background: Gait adaptability is of utmost importance for keeping balance during gait in patients with knee osteoarthritis, also after total knee arthroplasty (TKA). The aims of this explorative study are: (1) assess the effect of age, knee osteoarthritis and TKA on gait adaptability; (2) assess changes in gait adaptability pre-to post-TKA and (3) their relation to functional outcomes.

Methods: Gait adaptability was measured using a Target Stepping Test (TST) in knee osteoarthritis patients before (preTKA) and 12 months after TKA (postTKA) and compared to asymptomatic old (AsOld) and young adults (AsYng).

Reconstituted TAD-size chromatin fibers feature heterogeneous nucleosome clusters.

Large topologically associated domains (TADs) contain irregularly spaced nucleosome clutches, and interactions between such clutches are thought to aid the compaction of these domains. Here, we reconstituted TAD-sized chromatin fibers containing hundreds of nucleosomes on native source human and lambda-phage DNA and compared their mechanical properties at the single-molecule level with shorter '601' arrays with various nucleosome repeat lengths. Fluorescent imaging showed increased compaction upon saturation of the DNA with histones and increasing magnesium concentration.

Columnar structure of human telomeric chromatin.

Telomeres, the ends of eukaryotic chromosomes, play pivotal parts in ageing and cancer and are targets of DNA damage and the DNA damage response. Little is known about the structure of telomeric chromatin at the molecular level. Here we used negative stain electron microscopy and single-molecule magnetic tweezers to characterize 3-kbp-long telomeric chromatin fibres.

Neuroprotection care bundle implementation is associated with improved long-term neurodevelopmental outcomes in extremely premature infants.

Objective: To study the impact of an evidence-based neuroprotection care (NPC) bundle on long-term neurodevelopmental impairment (NDI) in infants born extremely premature.

Study Design: An NPC bundle targeting predefined risk factors for acute brain injury in extremely preterm infants was implemented. We compared the incidence of composite outcome of death or severe neurodevelopmental impairment (sNDI) at 21 months adjusted age pre and post bundle implementation.

The Amsterdam Foot Model: a clinically informed multi-segment foot model developed to minimize measurement errors in foot kinematics.

Background: Foot and ankle joint kinematics are measured during clinical gait analyses with marker-based multi-segment foot models. To improve on existing models, measurement errors due to soft tissue artifacts (STAs) and marker misplacements should be reduced. Therefore, the aim of this study is to define a clinically informed, universally applicable multi-segment foot model, which is developed to minimize these measurement errors.

Exploring molecular biology in sequence space: The road to next-generation single-molecule biophysics.

Next-generation sequencing techniques have led to a new quantitative dimension in the biological sciences. In particular, integrating sequencing techniques with biophysical tools allows sequence-dependent mechanistic studies. Using the millions of DNA clusters that are generated during sequencing to perform high-throughput binding affinity and kinetics measurements enabled the construction of energy landscapes in sequence space, uncovering relationships between sequence, structure, and function.

Multiplexed two-photon excitation spectroscopy of single gold nanorods.

Plasmonic metallic nanoparticles are commonly used in (bio-)sensing applications because their localized surface plasmon resonance is highly sensitive to changes in the environment. Although optical detection of scattered light from single particles provides a straightforward means of detection, the two-photon luminescence (TPL) of single gold nanorods (GNRs) has the potential to increase the sensitivity due to the large anti-Stokes shift and the non-linear excitation mechanism. However, two-photon microscopy and spectroscopy are restricted in bandwidth and have been limited by the thermal stability of GNRs.

Coating gold nanorods with self-assembling peptide amphiphiles promotes stability and facilitates two-photon imaging.

Gold nanorods (GNRs) are versatile asymmetric nanoparticles with unique optical properties. These properties make GNRs ideal agents for applications such as photothermal cancer therapy, biosensing, and imaging. However, as-synthesised GNRs need to be modified with a biocompatible stabilising coating in order to be employed in these fields as the ligands used to stabilise GNRs during synthesis are toxic.

Muscle weakness is associated with non-contractile muscle tissue of the vastus medialis muscle in knee osteoarthritis.

Background: Quadriceps weakness is assumed to be associated with compositional properties of the vastus medialis muscle in patients with knee osteoarthritis (OA).

Methods: The aim was to determine the association of non-contractile muscle tissue in the vastus medialis muscle, measured with routine MRI, with muscle extensor strength in patients with knee OA. Sagittal T1-weighted 3T MRI of 94 patients with knee OA, routinely acquired in clinical practice were used for analysis.

Analysis of the H-Ras mobility pattern in vivo shows cellular heterogeneity inside epidermal tissue.

Developments in single-molecule microscopy (SMM) have enabled imaging individual proteins in biological systems, focusing on the analysis of protein mobility patterns inside cultured cells. In the present study, SMM was applied in vivo, using the zebrafish embryo model. We studied dynamics of the membrane protein H-Ras, its membrane-anchoring domain, C10H-Ras, and mutants, using total internal reflection fluorescence microscopy.

A most painful knee does not induce interlimb differences in knee and hip moments during gait in patients with knee osteoarthritis.

Background: Patients with knee osteoarthritis can adapt their gait to unload the most painful knee joint in order to try to reduce pain and improve physical function. However, these gait adaptations can cause higher loads on the contralateral joints. The aim of the study was to investigate the interlimb differences in knee and hip frontal plane moments during gait in patients with knee osteoarthritis and in healthy controls.

Marker placement sensitivity of the Oxford and Rizzoli foot models in adults and children.

Understanding the effect of individual marker misplacements is important to improve the repeatability and aid to the interpretation of multi-segment foot models like the Oxford and Rizzoli Foot Models (OFM, RFM). Therefore, this study aimed to quantify the effect of controlled anatomical marker misplacement on multi-segment foot kinematics (i.e.

Responses in knee joint muscle activation patterns to different perturbations during gait in healthy subjects.

Purpose: To compare the responses in knee joint muscle activation patterns to different perturbations during gait in healthy subjects.

Scope: Nine healthy participants were subjected to perturbed walking on a split-belt treadmill. Four perturbation types were applied, each at five intensities.

How to compare knee kinetics at different walking speeds?

Background: Walking speed is a confounding factor in biomechanical analyses of gait, but still many studies compare gait biomechanics at comfortable walking speed (CWS) that is likely to differ between groups or conditions. To identify gait deviation unrelated to walking speed, methods are needed to correct biomechanical data over the gait cycle for walking speed.

Research Question: How to compare knee kinetics over the gait cycle at different walking speeds?

Methods: 22 asymptomatic subjects walked on a dual-belt treadmill at CWS and 4 fixed speeds.

Inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait in patients with knee osteoarthritis.

Background: Gait analysis has been used for decades to quantify knee function in patients with knee osteoarthritis; however, it is unknown whether and to what extent inter-laboratory differences affect the comparison of gait data between studies. Therefore, the aim of this study was to perform an inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait of patients with knee osteoarthritis.

Methods: Knee biomechanics and muscle activation patterns from patients with knee osteoarthritis were analyzed, previously collected at Dalhousie University (DAL: n = 55) and Amsterdam UMC, VU medical center (VUmc: n = 39), using their in-house protocols.