Morpho-functional analysis of patient-derived xenografts reveals differential impact of gastric cancer and chemotherapy on the tumor ecosystem, affecting immune check point, metabolism, and sarcopenia.

OBJECTIVES: Gastric cancer (GC) is an aggressive disease due to late diagnosis resulting from the lack of easy diagnostic tools, resistances toward immunotherapy (due to low PD-L1 expression), or chemotherapies (due to p53 mutations), and comorbidity factors, notably muscle atrophy. To improve our understanding of this complex pathology, we established patient-derived xenograft (PDX) models and characterized the tumor ecosystem using a morpho-functional approach combining high-resolution imaging with molecular analyses, regarding the expression of relevant therapeutic biomarkers and the presence of muscle atrophy. MATERIALS AND METHODS: GC tissues samples were implanted in nude mice. Established PDX, treated with cisplatin or not, were imaged by magnetic resonance imaging (MRI) and analyzed for the expression of relevant biomarkers (p53, PD-L1, PD-1, HER-2, CDX2, CAIX, CD31, a-SAM) and by transcriptomics. RESULTS: Three well-differentiated, one moderately and one poorly differentiated adenocarcinomas were established. All retained the architectural and histological features of their primary tumors. MRI allowed in-real-time evaluation of differences between PDX, in terms of substructure, post-therapeutic changes, and muscle atrophy. Immunohistochemistry showed differential expression of p53, HER-2, CDX2, a-SAM, PD-L1, PD-1, CAIX, and CD31 between models and upon cisplatin treatment. Transcriptomics revealed treatment-induced hypoxia and metabolic reprograming in the tumor microenvironment. CONCLUSION: Our PDX models are representative for the heterogeneity and complexity of human tumors, with differences in structure, histology, muscle atrophy, and the different biomarkers making them valuable for the analyses of the impact of platinum drugs or new therapies on the tumor and its microenvironment.

The state of distance healthcare simulation during the COVID-19 pandemic: results of an international survey.

BACKGROUND: The coronavirus pandemic continues to shake the embedded structures of traditional in-person education across all learning levels and across the globe. In healthcare simulation, the pandemic tested the innovative and technological capabilities of simulation programs, educators, operations staff, and administration. This study aimed to answer the question: What is the state of distance simulation practice in 2021? METHODS: This was an IRB-approved, 34-item open survey for any profession involved in healthcare simulation disseminated widely and internationally in seven languages from January 14, 2021, to March 3, 2021. Development followed a multistep process of expert design, testing, piloting, translation, and recruitment. The survey asked questions to understand: Who was using distance simulation? What driving factors motivated programs to initiate distance sim? For what purposes was distance sim being used? What specific types or modalities of distance simulation were occurring? How was it being used (i.e., modalities, blending of technology and resources and location)? How did the early part of the pandemic differ from the latter half of 2020 and early 2021? What information would best support future distance simulation education? Data were cleaned, compiled, and analyzed for dichotomized responses, reporting frequencies, proportions, as well as a comparison of response proportions. RESULTS: From 32 countries, 618 respondents were included in the analysis. The findings included insights into the prevalence of distance simulation before, during, and after the pandemic; drivers for using distance simulation; methods and modalities of distance simulation; and staff training. The majority of respondents (70%) reported that their simulation center was conducting distance simulation. Significantly more respondents indicated long-term plans for maintaining a hybrid format (82%), relative to going back to in-person simulation (11%, p < 0.001). CONCLUSION: This study gives a perspective into the rapid adaptation of the healthcare simulation community towards distance teaching and learning in reaction to a radical and quick change in education conditions and environment caused by COVID-19, as well as future directions to pursue understanding and support of distance simulation.

Electric and antiferromagnetic chiral textures at multiferroic domain walls.

Chirality, a foundational concept throughout science, may arise at ferromagnetic domain walls1 and in related objects such as skyrmions2. However, chiral textures should also exist in other types of ferroic materials, such as antiferromagnets, for which theory predicts that they should move faster for lower power3, and ferroelectrics, where they should be extremely small and possess unusual topologies4,5. Here, we report the concomitant observation of antiferromagnetic and electric chiral textures at domain walls in the room-temperature ferroelectric antiferromagnet BiFeO3. Combining reciprocal and real-space characterization techniques, we reveal the presence of periodic chiral antiferromagnetic objects along the domain walls as well as a priori energetically unfavourable chiral ferroelectric domain walls. We discuss the mechanisms underlying their formation and their relevance for electrically controlled topological oxide electronics and spintronics.

Author Correction: Electric and antiferromagnetic chiral textures at multiferroic domain walls.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The efficacy of 16S ribosomal DNA sequencing in the diagnosis of bacteria from blood, bone and synovial fluid samples of children with musculoskeletal infections.

BACKGROUND: Musculoskeletal infections are among the most common bacterial infections in children leading to hospitalization, invasive procedures and prolonged antibiotic administration. Blood, synovial and sometimes tissue cultures are essential for the diagnosis and treatment of musculoskeletal infections; 16S ribosomal DNA (rDNA) sequencing is a novel diagnostic tool for the detection of bacteria.While the yield of 16S rDNA sequencing in synovial fluid was previously assessed, data regarding the efficacy of this method from blood samples or partially treated children with suspected musculoskeletal infections is lacking.In this study we assessed the yield of 16S rDNA sequencing in blood, bone and synovial samples of children with musculoskeletal infections. METHODS: Blood, synovial and bone samples were collected from children with suspected musculoskeletal infections and analyzed for the presence of 16S rDNA, the results were then compared with the benchmark microbial cultures. RESULTS: During the study period, 41 children (18 boys and 23 girls) with suspected acute musculoskeletal infection were enrolled. A positive blood culture was found in 6/31 cases (19.4%) with methicillin-susceptible Staphylococcus aureus being the most commonly isolated bacterium. No significant 16S rDNA detection in blood samples was recorded.Synovial fluid culture was positive in 6/28 samples (21%), Kingella kingae being the most common pathogen. When using the 16S rDNA sequencing method, the rate of positive results in synovial fluid was higher with bacterial detection in 12/23 (52%) samples. The 16S rDNA sequencing method was also able to identify pathogens in samples taken from partially treated children where cultures were negative with 16S rDNA detection in 5/5 samples. CONCLUSION: Although 16S rDNA sequencing may increase the yield of bacterial detection in synovial samples of patients with musculoskeletal infections, there is no benefit from applying this method on blood samples. The 16S rDNA sequencing method may be particularly beneficial when antibiotic treatment was started prior to synovial fluid sampling. LEVEL OF EVIDENCE: Level-II diagnostic study.

Real-space imaging of non-collinear antiferromagnetic order with a single-spin magnetometer.

Although ferromagnets have many applications, their large magnetization and the resulting energy cost for switching magnetic moments bring into question their suitability for reliable low-power spintronic devices. Non-collinear antiferromagnetic systems do not suffer from this problem, and often have extra functionalities: non-collinear spin order may break space-inversion symmetry and thus allow electric-field control of magnetism, or may produce emergent spin-orbit effects that enable efficient spin-charge interconversion. To harness these traits for next-generation spintronics, the nanoscale control and imaging capabilities that are now routine for ferromagnets must be developed for antiferromagnetic systems. Here, using a non-invasive, scanning single-spin magnetometer based on a nitrogen-vacancy defect in diamond, we demonstrate real-space visualization of non-collinear antiferromagnetic order in a magnetic thin film at room temperature. We image the spin cycloid of a multiferroic bismuth ferrite (BiFeO3) thin film and extract a period of about 70 nanometres, consistent with values determined by macroscopic diffraction. In addition, we take advantage of the magnetoelectric coupling present in BiFeO3 to manipulate the cycloid propagation direction by an electric field. Besides highlighting the potential of nitrogen-vacancy magnetometry for imaging complex antiferromagnetic orders at the nanoscale, these results demonstrate how BiFeO3 can be used in the design of reconfigurable nanoscale spin textures.

Current-induced skyrmion generation and dynamics in symmetric bilayers.

Magnetic skyrmions are quasiparticle-like textures which are topologically different from other states. Their discovery in systems with broken inversion symmetry sparked the search for materials containing such magnetic phase at room temperature. Their topological properties combined with the chirality-related spin-orbit torques make them interesting objects to control the magnetization at nanoscale. Here we show that a pair of coupled skyrmions of opposite chiralities can be stabilized in a symmetric magnetic bilayer system by combining Dzyaloshinskii-Moriya interaction (DMI) and dipolar coupling effects. This opens a path for skyrmion stabilization with lower DMI. We demonstrate in a device with asymmetric electrodes that such skyrmions can be independently written and shifted by electric current at large velocities. The skyrmionic nature of the observed quasiparticles is confirmed by the gyrotropic force. These results set the ground for emerging spintronic technologies where issues concerning skyrmion stability, nucleation and propagation are paramount.

Prognostic factors of hemorrhagic complications after oxaliplatin-based hyperthermic intraperitoneal chemotherapy: Toward routine preoperative dosage of Von Willebrand factor?

BACKGROUND: Oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC-ox) induces specific morbidity with hemorrhagic complications (HC). The aim of this study was to identify preoperative, intraoperative and postoperative HC predictive factors after HIPEC-ox. METHODS: A prospective single center study that included all consecutive patients treated with curative-intent HIPEC-ox, whatever the origin of peritoneal disease, was conducted. All patients underwent systematic blood tests exploring primary hemostasis and endothelial activation before surgical incision (D0) and on postoperative days 2 (POD2) and 5 (POD5). RESULTS: Between May 2012 and August 2015, 47 patients were enrolled in the study. The overall HC rate was 38%. Major morbidity was significantly higher in patients with HC. Patients presenting HC were significantly more often affected with pseudomyxoma peritonei and had less preoperative chemotherapy. Multivariate analysis showed that a higher plasmatic level of Von Willebrand factor antigen at D0 (D0 VWF:Ag) was a protective predictive factor for HC (p = 0.049, HR: 0.97 CI 95% [0.94-1.00]). A D0 VWF:Ag level below 138% had a sensitivity of 87.5%, a specificity of 67% and an area under the curve of 80.3% (CI 95% [66.5-94], p < 0.01) for predicting HC. CONCLUSIONS: Through the identification of prognostic factors, this study highlighted a subgroup of patients with low risk of HC after HIPEC-ox. Based on these results, we propose a routine preoperative dosage of VWF that would help the surgeon to select the most suitable patients for HIPEC-ox.

Performance of biomarkers SMRP, CA125, and CYFRA 21-1 as potential tumor markers for malignant mesothelioma and lung cancer in a cohort of workers formerly exposed to asbestos.

The aim of the study is to examine the cancer-predictive values of SMRP (soluble mesothelin-related peptides), CA125, and CYFRA21-1 as potential tumor markers for lung cancer and malignant mesothelioma in a cohort of workers formerly exposed to asbestos. A voluntary surveillance program has been established for German workers with former asbestos exposure. A subgroup of 626 subjects with a mean age of 63 years (range 53-70 years) at baseline was enrolled in an extended health examination program with high-resolution computer tomography (HRCT) of the chest and blood drawing between 1993 and 1997. Serum concentrations of SMRP, CA125, and CYFRA21-1 were measured in archived serum samples in 2005 and 2006. A mortality follow-up was conducted through 2007. So far, 12 cases with lung cancer and 20 cases with malignant mesothelioma have been observed in this cohort. The average time between sample collection and diagnosis was 4.7 years. Analyzed biomarkers showed low sensitivities (5-25%) and positive predictive values (4-30%) for both cancer sites. Marker combinations resulted in sensitivities between 5 and 50% and positive predictive values ranging from 3 to 14%. Even in those cases, where biomarker concentrations were available within 36 months before diagnosis, no trend for increasing biomarker levels was observed. The analyzed tumor markers were characterized by high specificities, but low sensitivities. SMRP, CA125, and CYFRA21-1 alone or in combination were less suitable to serve as predictors for the diagnosis of lung cancer or malignant mesothelioma. However, a prospective study with annual sampling might reveal a better predictive value of these markers.

Decontamination of the skin with absorbing materials.

Stimulation of the penetration of topically applied substances into the skin is a topic of intensive dermatological and pharmacological research. Next to intercellular penetration, i.e. a penetration inside the lipid layers around the corneocytes, follicular penetration also represents an efficient penetration pathway. The hair follicles act as a long-term reservoir for topically applied substances. They are surrounded by or contain several important target structures, such as blood capillaries, stem cells and dendritic cells. Therefore, the hair follicles have to be well protected from hazardous substances coming into contact with the skin. The traditional method of decontamination of the skin involves an intensive washing procedure. However, this process represents a massage, which pushes the hazardous substances even deeper into the hair follicles. In the present study, the application of absorbing materials for decontamination of the skin was investigated after the application of a model substance utilizing the tape-stripping procedure. It was found that absorbing materials are better suited than the washing process for decontamination of the skin.

The intestine-specific homeobox gene Cdx2 decreases mobility and antagonizes dissemination of colon cancer cells.

The gravity of colorectal cancer is mainly due to the capacity of tumor cells to migrate out of the tumor mass to invade the stroma and disseminate as metastases. The acquisition of a migratory phenotype also occurs during wound healing. Here, we show that several features characterizing invasive colon tumor cells are shared by migrating cells during wound repair in vitro. In particular, the expression of the intestine-specific transcription factor Cdx2, a key gene for intestinal identity downregulated in invasive cancer cells, is reduced during wound healing in vitro. Transcription factors involved in epithelial-mesenchymal transition such as Snail and Slug are upregulated during wound healing and are able to repress Cdx2 transcription. In vitro, forced expression of Cdx2 in human colon cancer cell lines retarded wound repair and reduced migration, whereas inhibition of Cdx2 expression by RNA interference enhanced migration. In vivo, forced expression of Cdx2 opposed tumor cells spreading in nude mice xenografted at three different sites. These data provide evidence that Cdx2 antagonizes the process of tumor cell dissemination, and they suggest that this homeobox gene might represent a new therapeutic target against metastatic spreading of colon cancer.

Occupational risks for adenocarcinoma of the nasal cavity and paranasal sinuses in the German wood industry.

OBJECTIVES: To examine the risk of wood dust and chemical exposures for adenocarcinoma of the nasal cavity and paranasal sinuses (ADCN) among German wood workers. METHODS: An industry-based case-control study with 86 male ADCN cases and 204 controls was conducted in the German wood-working industries. Cumulative and average wood-dust exposure was quantified with a job-exposure matrix based on wood-dust measurements at recent and historical workplaces. Probabilities of exposure to wood preservatives, stains, varnishes, and formaldehyde were semi-quantitatively rated. Odds ratios and 95% confidence intervals were calculated with logistic regression analysis conditional on age and adjusted for smoking and other factors. For estimating the risks of either wood dust or chemical additives, the authors additionally adjusted for the corresponding co-exposure. RESULTS: ADCN occurred relatively more frequently among wood workers that had ever worked as cabinet makers or joiners (OR 2.96, 95% CI 1.46 to 6.01) than as saw millers (OR 0.15, 95% CI 0.03 to 0.68). Average exposure to inhalable wood dust >/=5 mg/m(3) was associated with a high risk (OR 48.47, 95% CI 13.30 to 176.63) compared to levels below 3.5 mg/m(3). Assuming 40 years of exposure under these concentrations, the corresponding OR was 4.20 (95% CI 1.69 to 10.43). Exposure between 3.5 and 5 mg/m(3) was also found to pose a risk (OR 10.54, 95% CI 3.34 to 33.27). Exposure to pigment stains before 1970 was associated with an increased risk (OR 3.03; 95% CI 1.11 to 8.26). No significant associations were estimated for wood preservatives, varnishes, and formaldehyde. CONCLUSIONS: The authors found an elevated ADCN risk for exposure to inhalable wood dust above 3.5 mg/m(3). The rareness of the disease does not allow the exclusion of risk below that concentration. For pigment stains, there is evidence for an association of historical exposure with the development of ADCN in German wood workers.

Multiple neurotoxic stresses converge on MDMX proteolysis to cause neuronal apoptosis.

MDMX has been shown to modulate p53 in dividing cells after DNA damage. In this study, we investigated the role of MDMX in primary cultures of neurons undergoing cell death. We found that DNA damage, but also membrane-initiated apoptotic stresses (glutamate receptor; Amyloid beta precursor) or survival factor deprivation downregulated MDMX protein levels. Forced downregulation of murine double minute X (MDMX) by shRNA induced apoptosis suggesting that MDMX is required for survival in neurons. Protease inhibitors prevented the loss of MDMX after neurotoxic treatments, indicating a regulation of protein stability. Some, but not all, neurotoxic stresses induced phosphorylation of MDMX at serine 367, further supporting regulation at the protein level. Interestingly, we found that depending on the stimulus either p53 or E2F1 was induced, but overexpression of MDMX inhibited the transcriptional activity of both proapoptotic factors, and maintained neuronal viability upon neurotoxic stresses. Taken together, our data show that MDMX is an antiapoptotic factor in neurons, whose degradation is induced by various stresses and allows activation of p53 and E2F-1 during neuronal apoptosis.

Different effects of the Cdx1 and Cdx2 homeobox genes in a murine model of intestinal inflammation.

AIMS: The CDX1 and CDX2 homeoproteins are intestine-specific transcription factors regulating homeostasis. We investigated their relevance in experimentally-induced intestinal inflammation. METHODS: The response to intestinal inflammation induced by dextran sodium sulfate (DSS) was compared in wild type, Cdx1(-/-) and Cdx2(+/-) mice. Intestinal permeability was determined in wild type and Cdx2(+/-) mice. Protein-protein interactions were investigated by co-immunoprecipitation and GST-pulldown, and their functional consequences were assessed using Luciferase reporter systems. RESULTS: Heterozygous Cdx2(+/-) mice, but not Cdx1(-/-) mice, were hypersensitive to DSS-induced acute inflammation as all these mice showed blood in the stools at day 1 of DSS treatment. Hypersensitivity was associated to a 50% higher intestinal permeability. In Cdx2(+/-) mice, the colonic epithelium was repaired during the week after the end of DSS treatment, whereas two weeks were required for wild type animals. Subsequently, no colonic tumour was observed in Cdx2(+/-) mice subjected to 5 repeated cycles of DSS, in contrast to the 2.7 tumours found per wild type mouse. Based on the fact that Smad3(+/-) mice, like Cdx2(+/-) mice, better repair the damaged intestinal epithelium, we found that the CDX2 protein interacts with SMAD3, independently of SMAD4, resulting in a 5-fold stimulation of SMAD3 transcriptional activity. CDX1 also interacted with SMAD3 but it inhibited by 10-fold the SMAD3/SMAD4-dependent transcription. CONCLUSION: The Cdx1 and Cdx2 homeobox genes have distinct effects on the outcome of a pro-inflammatory challenge. This is mirrored by different functional interactions of the CDX1 and CDX2 proteins with SMAD3, a major element of the TGFbeta signalling pathway.

Sprouty2 inhibits BDNF-induced signaling and modulates neuronal differentiation and survival.

Sprouty (Spry) proteins are ligand-inducible inhibitors of receptor tyrosine kinases-dependent signaling pathways, which control various biological processes, including proliferation, differentiation and survival. Here, we investigated the regulation and the role of Spry2 in cells of the central nervous system (CNS). In primary cultures of immature neurons, the neurotrophic factor BDNF (brain-derived neurotrophic factor) regulates spry2 expression. We identified the transcription factors CREB and SP1 as important regulators of the BDNF activation of the spry2 promoter. In immature neurons, we show that overexpression of wild-type Spry2 blocks neurite formation and neurofilament light chain expression, whereas inhibition of Spry2 by a dominant-negative mutant or small interfering RNA favors sprouting of multiple neurites. In mature neurons that exhibit an extensive neurite network, spry2 expression is sustained by BDNF and is downregulated during neuronal apoptosis. Interestingly, in these differentiated neurons, overexpression of Spry2 induces neuronal cell death, whereas its inhibition favors neuronal survival. Together, our results imply that Spry2 is involved in the development of the CNS by inhibiting both neuronal differentiation and survival through a negative-feedback loop that downregulates neurotrophic factors-driven signaling pathways.

Inhaled nitric oxide for the postoperative management of pulmonary hypertension in infants and children with congenital heart disease.

BACKGROUND: Nitric oxide (NO) is a prevalent molecule in the human body responsible for many physiologic activities including pulmonary vasodilation. An exogenous, inhaled form (iNO) exists that mimics this action without directly affecting systemic blood pressure. This therapy has been implemented in the treatment of pulmonary hypertension. This review examines the efficacy of iNO in the postoperative management of infants and children with congenital heart disease. OBJECTIVES: To compare the effects of postoperative iNO versus placebo and/or conventional management on infants and children with congenital heart disease. The primary outcome was mortality, while secondary outcomes included length of hospital stay, assessment of neurodevelopmental disability, number of pulmonary hypertensive crises (PHTC), changes in haemodynamics including mean pulmonary arterial pressure (MPAP), mean arterial pressure (MAP), and heart rate (HR), changes in oxygenation measured as the ratio PaO2:FiO2, and measurement of maximum methaemoglobin level as a marker of toxicity. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 3, 2004), MEDLINE (1966 to 2004), and EMBASE (1980 to 2004). We included abstracts and all languages. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials comparing iNO with placebo and conventional management, or both. Trials included only children with congenital heart disease requiring surgery and complicated by pulmonary hypertension. DATA COLLECTION AND ANALYSIS: Data were collected on mortality, number of PHTC, changes in MPAP, MAP, HR, and PaO2:FiO2, and maximum methaemoglobin level, while data on long-term mortality, neurodevelopmental disability, and length of hospital stay were unavailable. We performed subgroup analysis by age and method of control. We performed sensitivity analysis using studies of highest methodologic quality. MAIN RESULTS: We included four randomized trials. We observed no differences between groups with respect to mortality (P = 0.50), PHTC (P = 0.79), change in MPAP (P = 0.16), MAP (P = 0.40), HR (P = 1.00), or PaO2:FiO2 (P = 0.46). There was a significant reduction in MPAP in the subgroup of patients from birth to three months (P = 0.005), although this finding was based on a small number of patients (N = 23). AUTHORS' CONCLUSIONS: We observed no differences with the use of iNO as compared with control in the majority of outcomes reviewed. No data were available for analysis with respect to several clinical outcomes including long-term mortality and neurodevelopmental outcome. We found it difficult to draw valid conclusions because of concerns regarding methodologic quality, bias, sample size, and heterogeneity.

A navigated mechatronic system with haptic features to assist in surgical interventions.

OBJECTIVE: In orthopaedic surgery, the development of new computer-based technologies such as navigation systems and robotics will facilitate more precise, reproducible results in surgical interventions. There are already commercial systems available for clinical use, though these still have some limitations and drawbacks. This paper presents an alternative approach to a universal modular surgical assistant system for supporting less or minimally invasive surgery. MATERIALS AND METHODS: The position of a mechatronic arm, which is part of the system, is controlled by a navigation system so that small patient movements are automatically detected and compensated for in real time. Thus, the optimal tool position can be constantly maintained without the need for rigid bone or patient fixation. Furthermore, a force control mode of the mechatronic assistant system, based on a force-torque sensor, not only increases safety during surgical interventions but also facilitates hand-driven direct positioning of the arm. RESULTS: A prototype has been successfully tested in clinical applications at the Orthopadische Universitätsklinik Frankfurt. For the first time worldwide, implantation of the cup prosthesis in total hip replacement surgery has been carried out with the assistance of a mechatronic arm. According to measurements by the digitizing system, operating tool angle deviation remained below 0.5 degrees, relative to the preoperative planning. CONCLUSION: The presented approach to a new kind of surgical mechatronic assistance system supports the surgeon as needed by optimal positioning of the surgical instruments. Due to its modular design, it is applicable to a wide range of tasks in surgical interventions, e.g., endoscope guidance, bone preparation, etc.