Publications by authors named "Marc Koch"

The use of machine learning to predict postoperative pain and opioid use has likely been catalyzed by the availability of complex patient-level data, computational and statistical advancements, the prevalence and impact of chronic postsurgical pain, and the persistence of the opioid crisis. The objectives of this narrative review were to identify and characterize methodological aspects of studies that have developed and/or tested machine learning algorithms to predict acute, subacute, or chronic pain or opioid use after any surgery and to propose considerations for future machine learning studies. Pairs of independent reviewers screened titles and abstracts of 280 PubMed-indexed articles and ultimately extracted data from 61 studies that met entry criteria.

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The increasing research in the field of polymeric multi-channel membranes has shown that their mechanical stability is beneficial for a wide range of applications. The more complex interplay of formation process parameters compared to a single-channel geometry makes an investigation using Design of Experiments (DoE) appealing. In this study, seven-channel capillary membranes were fabricated in a steam⁻dry⁻wet spinning process, while varying the composition of the polymer solution and the process temperatures in a three-level fractional factorial linear screening design.

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The mechanical stability of conventional single-channel capillary fibres can be improved in a multi-channel geometry, which has previously found application in ultrafiltration. In this work, multi-channel polyethersulfone (PES) capillary membranes comprising seven feed channels were successfully fabricated in an enhanced steam⁻dry⁻wet spinning process and coated on the inner surface with a thin polyamide (PA) layer via interfacial polymerization (IP). The coating procedure consisted of impregnating the support multi-channel capillary membranes (MCM) with an aqueous piperazine solution, flushing with nitrogen gas to remove excess droplets, and pumping an organic trimesoylchloride solution through the channels.

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SAGA and ATAC are two distinct chromatin modifying co-activator complexes with distinct enzymatic activities involved in RNA polymerase II (Pol II) transcription regulation. To investigate the mobility of co-activator complexes and general transcription factors in live-cell nuclei, we performed imaging experiments based on photobleaching. SAGA and ATAC, but also two general transcription factors (TFIID and TFIIB), were highly dynamic, exhibiting mainly transient associations with chromatin, contrary to Pol II, which formed more stable chromatin interactions.

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Skeletal muscle structure and function are altered in different myopathies. However, the understanding of the molecular and cellular mechanisms mainly rely on and investigations in mammalian models. In order to monitor the intracellular structure of the neuromuscular system in its environment under normal and pathological conditions, we set-up and validated non-invasive imaging of ear and leg muscles in mice.

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DNA lesions are sensed by a network of proteins that trigger the DNA damage response (DDR), a signaling cascade that acts to delay cell cycle progression and initiate DNA repair. The Mediator of DNA damage Checkpoint protein 1 (MDC1) is essential for spreading of the DDR signaling on chromatin surrounding Double Strand Breaks (DSBs) by acting as a scaffold for PI3K kinases and for ubiquitin ligases. MDC1 also plays a role both in Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR) repair pathways.

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Opioid receptors are G protein-coupled receptors (GPCRs) that modulate brain function at all levels of neural integration, including autonomic, sensory, emotional and cognitive processing. Mu (MOR) and delta (DOR) opioid receptors functionally interact in vivo, but whether interactions occur at circuitry, cellular or molecular levels remains unsolved. To challenge the hypothesis of MOR/DOR heteromerization in the brain, we generated redMOR/greenDOR double knock-in mice and report dual receptor mapping throughout the nervous system.

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Tubular aggregates are regular arrays of membrane tubules accumulating in muscle with age. They are found as secondary features in several muscle disorders, including alcohol- and drug-induced myopathies, exercise-induced cramps, and inherited myasthenia, but also exist as a pure genetic form characterized by slowly progressive muscle weakness. We identified dominant STIM1 mutations as a genetic cause of tubular-aggregate myopathy (TAM).

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G-protein-coupled receptors (GPCRs) mediate numerous physiological functions and represent prime therapeutic targets. Receptor trafficking upon agonist stimulation is critical for GPCR function, but examining this process in vivo remains a true challenge. Using knock-in mice expressing functional fluorescent delta opioid receptors under the control of the endogenous promoter, we visualized in vivo internalization of this native GPCR upon physiological stimulation.

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Four key considerations can affect the size of an anesthesia subsidy: Staffing models. The fair market value compensation for clinicians. The type of provider the organization needs.

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Mechanotransduction refers to the transformation of physical forces into chemical signals. It generally involves stretch-sensitive channels or conformational change of cytoskeleton-associated proteins. Mechanotransduction is crucial for the physiology of several organs and for cell migration.

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In mammals, oocyte fertilization by sperm initiates development. This is followed by epigenetic reprogramming of both parental genomes, which involves the de novo establishment of chromatin domains. In the mouse embryo, methylation of histone H3 establishes an epigenetic asymmetry and is predominant in the maternal pronucleus.

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Background: In cell biology, the study of proteins and organelles requires the combination of different imaging approaches, from live recordings with light microscopy (LM) to electron microscopy (EM).

Methodology: To correlate dynamic events in adherent cells with both ultrastructural and 3D information, we developed a method for cultured cells that combines confocal time-lapse images of GFP-tagged proteins with electron microscopy. With laser micro-patterned culture substrate, we created coordinates that were conserved at every step of the sample preparation and visualization processes.

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Background: Heterogeneity in microvascular perfusion is associated with impaired tissue oxygenation. We hypothesized that cardiac surgery with or without cardiopulmonary bypass (CPB) could induce microvascular alterations.

Methods: We used an orthogonal polarization spectral imaging technique to evaluate the sublingual microcirculation in patients undergoing cardiac surgery with (n = 9) or without (n = 6) CPB.

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Previously, we have shown that thiopalmitoylation of peptides of myelin proteolipid protein, as occurs naturally in vivo, increases their ability to induce experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis, and skews the autoimmune response toward a CD4(+)-mediated response. In contrast, the same peptide, when synthesized with a stable amide bond between peptide and lipid, inhibits experimental autoimmune encephalomyelitis and skews the response toward a CD8(+) response. The aim of the current study was to determine the mechanisms responsible for these observations.

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Objectives: Microvascular alterations may play a role in the development of multiple organ failure in severe sepsis. The effects of red blood cell transfusions on microvascular perfusion are not well defined. We investigated the effects of red blood cell transfusion on sublingual microvascular perfusion in patients with sepsis.

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Objective: Pupillary reflex dilation (PRD) secondary to noxious stimulation accurately predicts sensory block during combined lumbar epidural/general anesthesia. Therefore, the adequacy of PRD-guided thoracic epidural infusion during general anesthesia for thoracotomy was studied.

Design: Prospective study.

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Objective: Microvascular alterations may play an important role in the development of sepsis-induced organ dysfunction. Drotrecogin alfa activated (DAA) improves outcome in patients with severe sepsis, but its precise mechanism of action is not entirely defined. We investigated whether DAA can influence microcirculatory alterations in patients with severe sepsis.

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Objective: To test the hypothesis that microcirculatory blood flow is the main determinant of sublingual carbon dioxide pressure in patients with septic shock.

Design: Prospective, open-label study.

Setting: A 31-bed medico-surgical department of intensive care.

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Objective: To evaluate the effects of dobutamine on microcirculatory blood flow alterations in patients with septic shock.

Design: Prospective, open-label study.

Setting: A 31-bed, medico-surgical intensive care unit of a university hospital.

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Objective: To define whether duration of anesthesia is an indicator of patient morbidity and mortality in facial plastic surgery performed in an accredited office-based surgical facility.

Design: A prospective and retrospective outcomes analysis of 1200 consecutive patients who underwent facial plastic surgery from July 1995 to February 2005. Outcomes of patients who underwent surgery with anesthesia for less than 240 minutes were compared with those of patients who underwent surgery with anesthesia for more than 240 minutes.

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Objective: To evaluate the influence of tidal volume on the capacity of pulse pressure variation (DeltaPP) to predict fluid responsiveness.

Design: Prospective interventional study.

Setting: A 31-bed university hospital medico-surgical ICU.

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