Imaging of RNA in situ hybridization by atomic force microscopy

In this study we investigated the possibility of imaging internal cellular molecules after cytochemical detection with atomic force microscopy (AFM). To this end, rat 9G and HeLa cells were hybridized with haptenized probes for 28S ribosomal RNA, human elongation factor mRNA and cytomegalovirus immediate early antigen mRNA. The haptenized hybrids were subsequently detected with a peroxidase-labelled antibody and visualized with 3,3'-diaminobenzidine (DAB). The influence of various scanning conditions on cell morphology and visibility of the signal was investigated. In order to determine the influence of ethanol dehydration on cellular structure and visibility of the DAB precipitate, cells were kept in phosphate-buffered saline (PBS) and scanned under fluid after DAB development or dehydrated and subsequently scanned dry or submerged in PBS. Direct information on the increase in height of cellular structures because of internally precipitated DAB and the height of mock-hybridized cells was available. Results show that internal DAB precipitate can be detected by AFM, with the highest sensitivity in the case of dry cells. Although a relatively large amount of DAB had to be precipitated inside the cell before it was visible by AFM, the resolution of AFM for imaging of RNA–in situ hybridization signals was slightly better than that of conventional optical microscopy. Furthermore, it is concluded that dehydration of the cells has irreversible effects on cellular structure. Therefore, scanning under fluid of previously dehydrated samples cannot be considered as a good representation of the situation before dehydration.\ud \u

Lung ultrasound and computed tomography to monitor COVID-19 pneumonia in critically ill patients: a two-center prospective cohort study

Background: Lung ultrasound can adequately monitor disease severity in pneumonia and acute respiratory distress syndrome. We hypothesize lung ultrasound can adequately monitor COVID-19 pneumonia in critically ill patients.Methods: Adult patients with COVID-19 pneumonia admitted to the intensive care unit of two academic hospitals who underwent a 12-zone lung ultrasound and a chest CT examination were included. Baseline characteristics, and outcomes including composite endpoint death or ICU stay > 30 days were recorded. Lung ultrasound and CT images were quantified as a lung ultrasound score involvement index (LUSI) and CT severity involvement index (CTSI). Primary outcome was the correlation, agreement, and concordance between LUSI and CTSI. Secondary outcome was the association of LUSI and CTSI with the composite endpoints.Results: We included 55 ultrasound examinations in 34 patients, which were 88% were male, with a mean age of 63 years and mean P/F ratio of 151. The correlation between LUSI and CTSI was strong (r = 0.795), with an overall 15% bias, and limits of agreement ranging - 40 to 9.7. Concordance between changes in sequentially measured LUSI and CTSI was 81%. In the univariate model, high involvement on LUSI and CTSI were associated with a composite endpoint. In the multivariate model, LUSI was the only remaining independent predictor.Conclusions: Lung ultrasound can be used as an alternative for chest CT in monitoring COVID-19 pneumonia in critically ill patients as it can quantify pulmonary involvement, register changes over the course of the disease, and predict death or ICU stay > 30 days.Perioperative Medicine: Efficacy, Safety and Outcome (Anesthesiology/Intensive Care

An unexpected signature of Lorenz-Mie scattering observed in flowcytometric experiments

Detailed analysis of elastic light scattering by spheresin FlowCytometers shows unexpected Lorenz-Miescattering patterns. The complete scattering matrix S ofspheres was measured. Two parameter scatterplots withx- and y- coordinates determined by the S11 + Sij andS11 - Sij values were obtained. Samples of sphereswith very narrow size distributions were analyzed andproduced unexpected two parameter scatterplots. Insteadof compact distributions we observed Lissajous-likeloops. Simulation of the scatterplots, using Lorenz-Mietheory, shows that these loops are not due toexperimental errors, but due to true Lorenz-Miescattering. We show that the loops originate from thesensitivity of the scattered field on the radius of thespheres. This work demonstrates that the interpretationof rare events and hidden features in FlowCytometryneeds reconsideration

Comparative atomic force and scanning electron microscopy: an investigation on fenestrated endothelial cells in vitro

Rat liver sinusoidal endothelial cells (LEC) contain fenestrae, which are clustered in sieve plates. Fenestrae control the exchange of fluids, solutes and particles between the sinusoidal blood and the space of Disse, which at its back side is flanked by the microvillous surface of the parenchymal cells. The surface of LEC can optimally be imaged by scanning electron microscopy (SEM), and SEM images can be used to study dynamic changes in fenestrae by comparing fixed specimens subjected to different experimental conditions. Unfortunately, the SEM allows only investigation of fixed, dried and coated specimens. Recently, the use of atomic force microscopy (AFM) was introduced for analysing the cell surface, independent of complicated preparation techniques. We used the AFM for the investigation of cultured LEC surfaces and the study of morphological changes of fenestrae. SEM served as a conventional reference.\ud \ud AFM images of LEC show structures that correlate well with SEM images. Dried-coated, dried-uncoated and wet-fixed LEC show a central bulging nucleus and flat fenestrated cellular processes. It was also possible to obtain height information which is not available in SEM. After treatment with ethanol or serotonin the diameters of fenestrae increased (+6%) and decreased (−15%), respectively. The same alterations of fenestrae could be distinguished by measuring AFM images of dried-coated, dried-uncoated and wet-fixed LEC. Comparison of dried-coated (SEM) and wet-fixed (AFM) fenestrae indicated a mean shrinkage of 20% in SEM preparations. In conclusion, high-resolution imaging with AFM of the cell surface of cultured LEC can be performed on dried-coated, dried-uncoated and wet-fixed LEC, which was hitherto only possible with fixed, dried and coated preparations in SEM and transmission electron microscopy (TEM).\u

Endothelium-associated biomarkers mid-regional proadrenomedullin and C-terminal proendothelin-1 have good ability to predict 28-day mortality in critically ill patients with SARS-CoV-2 pneumonia: A prospective cohort study

PURPOSE: We assessed the ability of mid-regional proadrenomedullin (MR-proADM) and C-terminal proendothelin-1 (CT-proET-1) to predict 28-day mortality in critically ill patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia. METHODS: Biomarkers were collected during the first seven days in this prospective observational cohort study. We investigated the relationship between biomarkers and mortality in a multivariable Cox regression model adjusted for age and SOFA score. RESULTS: In 105 critically ill patients with confirmed SARS-CoV-2 pneumonia 28-day mortality was 28.6%. MR-proADM and CT-proET-1 were significantly higher in 28-day non-survivors at baseline and over time. ROC curves revealed high accuracy to identify non-survivors for baseline MR-proADM and CT-proET-1, AUC 0.84, (95% CI 0.76–0.92), p < 0.001 and 0.79, (95% CI 0.69–0.89), p < 0.001, respectively. The AUC for prediction of 28-day mortality for MR-proADM and CT-proET-1 remained high over time. MR-proADM ≥1.57 nmol/L and CT-proET-1 ≥ 111 pmol/L at baseline were significant predictors for 28-day mortality (HR 6.80, 95% CI 3.12–14.84, p < 0.001 and HR 3.72, 95% CI 1.71–8.08, p 0.01). CONCLUSION: Baseline and serial MR-proADM and CT-proET-1 had good ability to predict 28-day mortality in critically ill patients with SARS-CoV-2 pneumonia. TRIAL REGISTRATION: NEDERLANDS TRIAL REGISTER, NL8460

Utilization of diagnostic resources and costs in patients with suspected cardiac chest pain

Aims Non-acute chest pain is a common complaint and can be caused by various conditions. With the rising healthcare expenditures of today, it is necessary to use our healthcare resources effectively. This study aims to give insight into the diagnostic effort and costs for patients with non-acute chest pain.Methods and results Financial data of patients without a cardiac history from four hospitals (January 2012-October 2018), who were registered with the national diagnostic code 'no cardiac pathology' (ICD-10 Z13.6), 'chest wall syndrome' (ICD-10 R07.4), or 'stable angina pectoris' (ICD-10 I20.9) were extracted. In total, 74 091 patients were included for analysis and divided into the following final diagnosis groups: no cardiac pathology: N=19 688 (age 5318), 46% male; chest wall syndrome: N=40 858 (age 56 +/- 15), 45% male; and stable angina pectoris (AP): N=13 545 (age 67 +/- 11), 61% male. A total of approximately (sic)142.7 million was spent during diagnostic work-up. The total expenditure during diagnostic effort was (sic)1.97, (sic)8.13, and (sic)10.7 million, respectively for no cardiac pathology, chest wall syndrome, and stable AP per year. After 8years of follow-up, >= 95% of the patients diagnosed with no cardiac pathology or chest wall syndrome had an (cardiac) ischaemic-free survival.Conclusion The diagnostic expenditure and clinical effort to ascertain non-cardiac chest pain are high. We should define what we as society find acceptable as 'assurance costs' with an increasing pressure on the healthcare system and costs.Cardiolog

Validity of surrogate endpoints assessing central venous catheter-related infection: evidence from individual- and study-level analyses

International audienceObjectives: The prevention of catheter-related bloodstream infection (CRBSI) has been an area of intense research, but the heterogeneity of endpoints used to define catheter infection makes the interpretation of randomized controlled trials (RCTs) problematic. The aim of this study was to determine the validity of different endpoints for central venous catheter infections.Data sources: (a) Individual-catheter data were collected from 9428 catheters from four large RCTs; (b) study-level data from 70 RCTs were identified with a systematic search. Eligible studies were RCTs published between January 1987 and October 2018 investigating various interventions to reduce infections from short-term central venous catheters or short-term dialysis catheters. For each RCT the prevalence rates of CRBSI, quantitative catheter tip colonization, catheter-associated infection (CAI) and central line-associated bloodstream infection (CLABSI) were extracted for each randomized study arm.Methods: CRBSI was used as the gold-standard endpoint, for which colonization, CAI and CLABSI were evaluated as surrogate endpoints. Surrogate validity was assessed as (1) the individual partial coefficient of determination (individual-pR2) using individual catheter data; (2) the coefficient of determination (study-R2) from mixed-effect models regressing the therapeutic effect size of the surrogates on the effect size of CRBSI, using study-level data.Results: Colonization showed poor agreement with CRBSI at the individual-patient level (pR2 = 0.33 95% CI 0.28-0.38) and poor capture at the study level (R2 = 0.42, 95% CI 0.21-0.58). CAI showed good agreement with CRBSI at the individual-patient level (pR2 = 0.80, 95% CI 0.76-0.83) and moderate capture at the study level (R2 = 0.71, 95% CI 0.51-0.85). CLABSI showed poor agreement with CRBSI at the individual patient level (pR2 = 0.34, 95% CI 0.23-0.46) and poor capture at the study level (R2 = 0.28, 95% CI 0.07-0.76).Conclusions: CAI is a moderate to good surrogate endpoint for CRBSI. Colonization and CLABSI do not reliably reflect treatment effects on CRBSI and are consequently more suitable for surveillance than for clinical effectiveness research