Publications by authors named "Christian Praetorius"

Background And Aims: This study sought to determine the value of patient-derived organoids (PDOs) from esophago-gastric adenocarcinoma (EGC) for response prediction to neoadjuvant chemotherapy (neoCTx).

Methods: Endoscopic biopsies of patients with locally advanced EGC (n = 120) were taken into culture and PDOs expanded. PDOs' response towards the single substances of the FLOT regimen and the combination treatment were correlated to patients' pathological response using tumor regression grading.

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Background: Colorectal cancer stands as a prevalent cause of cancer-related mortality, necessitating effective treatment strategies. Acute colonic obstruction occurs in approximately 20% of patients and represents a surgical emergency with substantial morbidity and mortality. The optimal approach for managing left-sided colon cancer with acute colonic obstruction remains debatable, with no consensus on whether emergency resection or bridge-to-surgery, involving initial decompressing stoma and subsequent elective resection after recovery, should be employed.

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Study Objectives: Airway inflammation in patients with obstructive sleep apnea (OSA) has been described and can be assessed by measuring the biomarker fractional exhaled nitric oxide (FeNO). In this pilot study, we investigated FeNO measurements in identification of OSA among persons with snoring.

Methods: In this study we aimed to investigate (1) if FeNO could be used in screening for OSA, (2) if daytime sleepiness correlated to FeNO levels, and (3) whether asthma affected FeNO levels.

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Purpose: Robotic-assisted minimally invasive esophagectomy (RAMIE) has become one standard approach for the operative treatment of esophageal tumors at specialized centers. Here, we report the results of a prospective multicenter registry for standardized RAMIE.

Methods: The German da Vinci Xi registry trial included all consecutive patients who underwent RAMIE at five tertiary university centers between Oct 17, 2017, and Jun 5, 2020.

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Second generation TRAIL-based therapeutics, combined with sensitising co-treatments, have recently entered clinical trials. However, reliable response predictors for optimal patient selection are not yet available. Here, we demonstrate that a novel and translationally relevant hexavalent TRAIL receptor agonist, IZI1551, in combination with Birinapant, a clinically tested IAP antagonist, efficiently induces cell death in various melanoma models, and that responsiveness can be predicted by combining pathway analysis, data-driven modelling and pattern recognition.

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Targeted therapy with BRAF inhibitors (BRAFi) and MEK inhibitors (MEKi) provides rapid disease control with high response rates in patients with BRAF-mutant metastatic melanoma. However, the majority of patients develop resistance to therapy during the course of therapy. Immune checkpoint inhibitors show a slower onset of action with lower response rates, with responders showing sustained response.

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NRAS mutations in malignant melanoma are associated with aggressive disease requiring rapid antitumor intervention, but there is no approved targeted therapy for this subset of patients. In clinical trials, the MEK inhibitor (MEKi) binimetinib displayed modest antitumor activity, making combinations a requisite. In a previous study, the BRAF inhibitor (BRAFi) vemurafenib was shown to induce endoplasmic reticulum (ER) stress that together with inhibition of the RAF-MEK-ERK (MAPK) pathway amplified its proapoptotic activity in BRAF-mutant melanoma.

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Purpose: Great advances have recently been made in treating patients with metastatic melanoma. However, existing therapies are less effective on cerebral than extracerebral metastases. This highlights the potential role of the brain environment on tumor progression and drug resistance and underlines the need for "brain-specific" therapies.

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Freckles, the lay term for ephelides and lentigines, are important pigmentation characteristics observed in humans. Both are affected by sunlight; ephelides are largely genetically determined but induced by sunlight, whereas lentigines are induced by sun exposure and photodamage of the skin. However, despite being commonly observed, we know very little about them.

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Sequence polymorphisms linked to human diseases and phenotypes in genome-wide association studies often affect noncoding regions. A SNP within an intron of the gene encoding Interferon Regulatory Factor 4 (IRF4), a transcription factor with no known role in melanocyte biology, is strongly associated with sensitivity of skin to sun exposure, freckles, blue eyes, and brown hair color. Here, we demonstrate that this SNP lies within an enhancer of IRF4 transcription in melanocytes.

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The Microphthalmia associated transcription factor (Mitf) is an important regulator in melanocyte development and has been shown to be involved in melanoma progression. The current model for the role of Mitf in melanoma assumes that the total activity of the protein is tightly regulated in order to secure cell proliferation. Previous research has shown that regulation of Mitf is complex and involves regulation of expression, splicing, protein stability and post-translational modifications.

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Using density functional calculations, we have studied the magnetic properties of nanocomposites composed of rare-earth-metal elements in contact with 3d transition metals (Fe and Cr). We demonstrate the possibility to obtain huge magnetic moments in such nanocomposites, of order 10mu(B)/rare-earth-metal atom, with a potential to reach the maximum magnetic moment of Fe-Co alloys at the top of the so-called Slater-Pauling curve. A first experimental proof of concept is given by thin-film synthesis of Fe/Gd and Fe/Cr/Gd nanocomposites, in combination with x-ray magnetic circular dichroism.

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The microphthalmia-associated transcription factor (Mitf) has emerged as an important model for gene regulation in eukaryotic organisms. In vertebrates, it regulates the development of several cell types including melanocytes and has also been shown to play an important role in melanoma. In vitro, the activity of MITF is regulated by multiple signaling pathways, including the KITL/KIT/B-Raf pathway, which results in phosphorylation of MITF on serine residues 73 and 409.

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Malignant melanoma is a chemotherapy-resistant cancer with high mortality. Recent advances in our understanding of the disease at the molecular level have indicated that it shares many characteristics with developmental precursors to melanocytes, the mature pigment-producing cells of the skin and hair follicles. The development of melanocytes absolutely depends on the action of the microphthalmia-associated transcription factor (MITF).

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