Publications by authors named "Schans E"

Parkinson's Disease (PD) develops unilaterally, which may be related to brain hemispheric differences in gene expression. Here we measured bulk RNA-seq levels in neuronal nuclei obtained from prefrontal cortex postmortem brain samples from males and females with PD and from healthy controls. Left and right hemispheres from each brain were related the side of symptom onset and compared.

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Genome-wide association studies have identified thousands of single nucleotide polymorphisms that associate with increased risk for Parkinson's disease (PD), but the functions of most of them are unknown. Using assay for transposase-accessible chromatin (ATAC) and H3K27ac chromatin immunoprecipitation (ChIP) sequencing data, we identified 73 regulatory elements in microglia that overlap PD risk SNPs. To determine the target genes of a "risk enhancer" within intron two of , we used CRISPR-Cas9 to delete the open chromatin region where two PD risk SNPs reside.

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One of the most significant risk variants for Parkinson's disease (PD), rs356182, is located at the PD-associated locus near the alpha-synuclein (α-syn) encoding gene, SNCA. SNCA-proximal variants, including rs356182, are thought to function in PD risk through enhancers via allele-specific regulatory effects on SNCA expression. However, this interpretation discounts the complex activity of genetic enhancers and possible non-conical functions of α-syn.

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Background: Surgeons have widely adopted endoscopic suturing techniques using conventional laparoscopic instruments and the more advanced robotic systems. The FlexDex is a novel articulating laparoscopic needle driver providing enhanced dexterity in laparoscopic surgery. This study evaluates and compares the learning curve of endoscopic suturing with conventional laparoscopy, the FlexDex and robotic suturing in novices.

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Background: Ventral mesh rectopexy (VMR) is a widely accepted surgical treatment for rectal prolapse. Both synthetic and biologic mesh are used. No consensus exists on the preferred type of mesh material.

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Aim: With increasing follow-up of patients treated with minimally invasive ventral mesh rectopexy (VMR) more redo surgery can be expected for recurrent rectal prolapse, mesh erosion and pelvic pain. The aim of this study is to evaluate the 90-day morbidity of robot-assisted redo interventions.

Method: All robot-assisted redo interventions after primary transabdominal repair of rectal prolapse between 2011 and 2019 were retrospectively analysed and compared with the results for patients after primary robot-assisted VMR during the same period.

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Background: The current standard treatment for external rectal prolapse and symptomatic high-grade internal rectal prolapse is surgical correction with minimally invasive ventral mesh rectopexy using either laparoscopy or robotic assistance. This study examines the number of procedures needed to complete the learning curve for robot-assisted ventral mesh rectopexy (RVMR) and reach adequate performance.

Methods: A retrospective analysis of all primary RVMR from 2011 to 2019 performed in a tertiary pelvic floor clinic by two colorectal surgeons (A and B) was performed.

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Genetic risk for complex diseases very rarely reflects only Mendelian-inherited phenotypes where single-gene mutations can be followed in families by linkage analysis. More commonly, a large set of low-penetrance, small effect-size variants combine to confer risk; they are normally revealed in genome-wide association studies (GWAS), which compare large population groups. Whereas Mendelian inheritance points toward disease mechanisms arising from the mutated genes, in the case of GWAS signals, the effector proteins and even general risk mechanism are mostly unknown.

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Background: Long-term data on robot-assisted sacrocolporectopexy for the treatment of multicompartment pelvic organ prolapse are scarce. With the rising prevalence of prolapse and increasing surgical repair, it is essential to evaluate long-term results.

Objective: This study aimed to evaluate long-term functional and anatomic outcomes after sacrocolporectopexy.

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Robot-assisted surgery is assumed to be time consuming partially due to extra time needed in preparing the robot. The objective of this study was to give realistic times in Da Vinci Xi draping and docking and to analyse the learning curve in the transition from the Si to the Xi in an experienced team. This prospective study was held in a hospital with a high volume of robot-assisted surgery in general surgery, urology and gynaecology.

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Background: Rectal prolapse-both external rectal prolapse and internal rectal prolapse-is a disabling condition. In view of the overwhelming number of surgical procedures described for the treatment of rectal prolapse, a comprehensive update concerning the diagnostic and therapeutic pathway for this condition is required to draw recommendations for clinical practice. This initiative was commissioned by the Dutch Association for Surgery (Nederlandse Vereniging voor Heelkunde) as a multidisciplinary collaboration.

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A 14-year-old girl with anorexia nervosa was referred to our paediatric hospital. She had a five-day history of severe abdominal pain. On abdominal sonography and MRI a duodenal wall hematoma was seen, correlating anatomically to abdominal bruises found on physical examination.

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The HIV-1 Rev protein activates nuclear export of unspliced and partially spliced viral RNA transcripts, which encode the viral genome and the genes encoding viral structural proteins, by binding to and oligomerizing on the Rev Response Element (RRE). The human DEAD-box protein 1 (DDX1) enhances the RNA export activity of Rev through an unknown mechanism. Using a single-molecule assembly assay and various DDX1 mutants, we show that DDX1 acts through the RRE RNA to specifically accelerate the nucleation step of the Rev-RRE assembly process.

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Binding of extracellular ligands to G protein-coupled receptors (GPCRs) initiates transmembrane signaling by inducing conformational changes on the cytoplasmic receptor surface. Knowledge of this process provides a platform for the development of GPCR-targeting drugs. Here, using a site-specific Cy3 fluorescence probe in the human β2-adrenergic receptor (β2AR), we observed that individual receptor molecules in the native-like environment of phospholipid nanodiscs undergo spontaneous transitions between two distinct conformational states.

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DNA polymerases replicate DNA by catalyzing the template-directed polymerization of deoxynucleoside triphosphate (dNTP) substrates onto the 3' end of a growing DNA primer strand. Many DNA polymerases also possess a separate 3'-5' exonuclease activity that is used to remove misincorporated nucleotides from the nascent DNA (proofreading). The polymerase (pol) and exonuclease (exo) activities are spatially separated in different enzyme domains, indicating that a mechanism must exist to transfer the growing primer terminus from one site to the other.

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To execute their diverse range of biological functions, RNA molecules must fold into specific tertiary structures and/or associate with one or more proteins to form ribonucleoprotein (RNP) complexes. Single-molecule fluorescence spectroscopy is a powerful tool for the study of RNA folding and RNP assembly processes, directly revealing different conformational subpopulations that are hidden in conventional ensemble measurements. Moreover, kinetic processes can be observed without the need to synchronize a population of molecules.

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Upon associating with a proofreading polymerase, the nascent 3' end of a DNA primer/template has two possible fates. Depending upon its suitability as a substrate for template-directed extension or postsynthetic repair, it will bind either to the 5'-3' polymerase active site, yielding a polymerizing complex, or to the 3'-5' exonuclease site, yielding an editing complex. In this investigation, we use a combination of biochemical and biophysical techniques to probe the stoichiometry, thermodynamic, and kinetic stability of the polymerizing and editing complexes.

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DNA polymerases with intrinsic proofreading activity interact with DNA primer/templates in two distinct modes, corresponding to the complexes formed during the 5'-3' polymerization or 3'-5' editing of a nascent DNA chain. Thermodynamic measurements designed to quantify the energetic contributions of individual DNA-protein contacts in either the polymerizing or editing complexes are complicated by the fact that both species exist in solution and are not resolved in conventional DNA-protein binding assays. To overcome this problem, we have developed a new binding analysis that combines information from steady-state and time-resolved fluorescence experiments and uses the Klenow fragment of Escherichia coli DNA polymerase I (KF) and fluorescently labeled primer/template oligonucleotides as a model polymerase-DNA system.

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The Klenow fragment of Escherichia coli DNA polymerase I catalyzes template-directed synthesis of DNA and uses a separate 3'-5' exonuclease activity to edit misincorporated bases. The polymerase and exonuclease activities are contained in separate structural domains. In this study, nine Klenow fragment derivatives containing mutations within the polymerase domain were examined for their interaction with model primer-template duplexes.

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Frameshift mutagenesis occurs through the misalignment of primer and template strands during DNA synthesis and involves DNA intermediates that contain one or more extrahelical bases in either strand of the DNA substrate. To investigate whether these DNA structures are recognized by the proofreading apparatus of DNA polymerases, time-resolved fluorescence spectroscopy was used to examine the interaction between the Klenow fragment of DNA polymerase I and synthetic DNA primer-templates containing extrahelical bases at defined positions within the template strand. A dansyl probe attached to the DNA was used to measure the fractional occupancies of the polymerase and 3'-5' exonuclease sites of the enzyme for DNA substrates with and without the extrahelical bases.

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Site-directed mutagenesis and time-resolved fluorescence spectroscopy were used to evaluate the contributions of individual amino acid side chains to the binding of DNA primer-templates to the 3'-5' exonuclease site of the large proteolytic fragment (Klenow fragment) of DNA polymerase I. Mutations were introduced into side chains that have been shown crystallographically to be in close proximity to a DNA 3' terminus bound at the 3'-5' exonuclease site. The wild-type residues were replaced by alanine in each case.

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Seventy-five patients with Graves' disease have been treated by transantral orbital decompression. In the first post-operative month the average reduction in proptosis was 3 mm. In the years following the operation this reduction increased to an average of 4.

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