Humidity and measurement of volatile propofol using MCC-IMS (EDMON).

The bedside Exhaled Drug MONitor - EDMON measures exhaled propofol in ppbv every minute based on multi-capillary column - ion mobility spectrometry (MCC-IMS). The MCC pre-separates gas samples, thereby reducing the influence of the high humidity in human breath. However, preliminary analyses identified substantial measurement deviations between dry and humid calibration standards. We therefore performed an analytical validation of the EDMON to evaluate the influence of humidity on measurement performance. A calibration gas generator was used to generate gaseous propofol standards measured by an EDMON device to assess linearity, precision, carry-over, resolution, and the influence of different levels of humidity at 100% and 1.7% (without additional) relative humidity (reference temperature: 37°C). EDMON measurements were roughly half the actual concentration without additional humidity and roughly halved again at 100% relative humidity. Standard concentrations and EDMON values correlated linearly at 100% relative humidity (R²=0.97). The measured values were stable over 100min with a variance ≤ 10% in over 96% of the measurements. Carry-over effects were low with 5% at 100% relative humidity after 5min of equilibration. EDMON measurement resolution at 100% relative humidity was 0.4 and 0.6 ppbv for standard concentrations of 3 ppbv and 41 ppbv. The influence of humidity on measurement performance was best described by a second-order polynomial function (R²≥0.99) with influence reaching a maximum at about 70% relative humidity. We conclude that EDMON measurements are strongly influenced by humidity and should therefore be corrected for sample humidity to obtain accurate estimates of exhaled propofol concentrations.

Expression patterns of the immune checkpoint ligand CD276 in urothelial carcinoma.

BACKGROUND: CD276 is an immune checkpoint molecule. Elevated CD276 expression by urothelial carcinoma is associated with poor prognosis, but little is known about its expression across different tumor stages. We therefore investigated CD276 expression in bladder cancer (BC) cells and in tissue samples of BC stages from pT2 to pT4. METHODS: CD276 expression was explored in 4 urothelial cancer cell lines and 4 primary normal urothelial cell populations by quantitative RT-PCR, Western blot and flow cytometry. CD276 was investigated in bladder tumors from 98 patients by immunohistochemistry using a score (0-300) incorporating both, staining intensity and area of CD276 staining. Normal appearing urothelium in the bladder of the same patients served as controls. RESULTS: The urothelial carcinoma cell lines expressed significantly higher levels of CD276 on transcript (p < 0.006), total protein levels (p < 0.005), and on the cell surface (p < 0.02) when compared to normal urothelial cells. In pT2-T4 tumor tissue samples, CD276 was overexpressed (median score 185) when compared to corresponding healthy tissues from the same patients (median score 50; p < 0.001). No significant differences in CD276 expression were recorded in late, locally advanced ≥ pT3a tumors (median score 185) versus organ-confined < pT3a tumors (median score 190), but it was significantly lower in the normal urothelial tissue associated with ≥ pT3a tumors (median score 40) versus < pT3a tumors (median score 80; p < 0.05). CONCLUSION: CD276 expression is significantly elevated in urothelial carcinoma cells in all stages but varies between individuals considerably. Reduced CD276 expression in normal urothelial cells may imply that these cells would be protected from CD276-mediated immuno therapies.

[Molecular pathology of tuberculosis : Status, methodology, and limits]. / Molekularpathologie der Tuberkulose : Stellenwert, Methodik und Grenzen.

In the diagnosis of mycobacterioses, microbiological examination with culture and antibiogram, possibly in combination with molecular biological testing of the fresh material, still represents the gold standard. However, these methods are not available for formalin-fixed paraffin-embedded (FFPE) material or other fixed samples. For this reason, the first step in pathology is to attempt microscopic pathogen detection (ZN/Fite/rhodamine-auramine). Subsequently, molecular pathological examination for the detection of mycobacterial gene sequences should also be considered mandatory today. Although this has clear limits due to the material, it is nevertheless well suited, if carried out correctly, to detect a mycobacterial infection or make it unlikely. A negative result may favor an alternative diagnosis but does not completely rule out mycobacteriosis.For the therapy of tuberculosis or nontuberculous mycobacterial (NTM) disease, the reliable detection of the species and the determination of resistance is of utmost importance. With regard to therapy, the clinician cannot afford to make a false diagnosis. In case of doubt, a rebiopsy for sampling native material, particularly for microbiological testing, should be discussed.

Cost of multidrug resistant tuberculosis in Germany-An update.

BACKGROUND: In 2019, new therapeutic recommendations for multidrug-resistant (MDR-) and extensively drug-resistant (XDR) tuberculosis (TB) were published by the WHO, advocating the use of oral drugs and stepwise composition of antibiotic regimens. To date, the economic consequences of those recommendations in low incidence settings have not been evaluated. OBJECTIVE: To assess the costs of applying the new recommendations against a set of 86 MDR-TB/XDR-TB strains, each with individual phenotypic drug resistance patterns, identified in 2018/2019 by the German National Reference Center for Mycobacteria. METHODS: Hospitalization costs as covered by German statutory health insurance and the loss of productivity due to illness were calculated using the most recent 2018 statistical data. Costs due to combining five agents in the intensive phase and costs of outpatient monitoring were determined by Monte-Carlo simulation covering all treatment options over an 18-month period. Drug costs were compared to those arising under the approach recommended by the WHO in 2016. RESULTS: Hospitalization costs per MDR-TB patient were €30,152 and the mean costs of antimicrobials over a period of 18 months were €66,854 (range €20,671 to €187,444). Total treatment costs, including outpatient monitoring, were €73,551.56 per patient (range €30,114 to €145.878). In addition, we determined an average cost of €11,410.20 due to productivity loss over a period of 6 months sick leave. Despite a shortened minimum recommended treatment duration (18 versus 20 months), the estimated costs were 24.5% higher based on the 2019 recommendations as compared to the 2016 guideline version. CONCLUSION: Higher costs for treating MDR-TB/XDR-TB in Germany are to be expected under the new WHO regimens. However, it must be determined whether treatment duration and costs associated with sick leave may be further reduced in the future through shorter hospital stays and earlier culture conversion.

[The New WHO Guidelines for Rapid Diagnostics and Treatment of Drug-Resistant Tuberculosis Commented for Germany, Austria and Switzerland]. / Die neuen WHO-Empfehlungen für schnelle Diagnostik und Therapie resistenter Tuberkulose in Deutschland, Österreich und der Schweiz.

The increasing evidence has made it necessary to change international recommendations for the diagnosis and treatment of resistant tuberculosis repeatedly in the recent years. This year, the WHO has published comprehensive recommendations that take into account these developments. The current German tuberculosis guideline was published in 2017 with differing recommendations in some areas. Here the new WHO recommendations of 2020 for rapid diagnosis and therapy of resistant tuberculosis are summarized and the relevant differences are commented for Germany, Austria and Switzerland. A complete re-evaluation of the literature is currently taking place by updating the German-language AWMF 2k guidelines.

International Society of Cardiovascular Infectious Diseases Guidelines for the Diagnosis, Treatment and Prevention of Disseminated Mycobacterium chimaera Infection Following Cardiac Surgery with Cardiopulmonary Bypass.

Mycobacterial infection-related morbidity and mortality in patients following cardiopulmonary bypass surgery is high and there is a growing need for a consensus-based expert opinion to provide international guidance for diagnosing, preventing and treating in these patients. In this document the International Society for Cardiovascular Infectious Diseases (ISCVID) covers aspects of prevention (field of hospital epidemiology), clinical management (infectious disease specialists, cardiac surgeons, ophthalmologists, others), laboratory diagnostics (microbiologists, molecular diagnostics), device management (perfusionists, cardiac surgeons) and public health aspects.

The landscape of diagnostic mycobacteriology in Germany-challenges of decentralised care.

OBJECTIVE: To perform a nationwide inventory of diagnostic mycobacteriology services in Germany.METHOD: A survey was conducted among participants of the national mycobacteriology external quality assurance scheme asking for smear microscopy techniques, molecular assays, culture systems and drug susceptibility testing (DST) capacities for Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), and numbers of processed/culture-positive samples, and DSTs performed in 2016.RESULTS: We found that 170/238 laboratories (71.4%) provided data. Numbers of samples processed for culture varied between 35 and 40 000 (median 1856, interquartile range [IQR] 761-3500). Specimen numbers culture-positive for MTBC or NTM ranged from 0 to 1895 (median 46, IQR 17-116), and from 0 to 833 (median 30, IQR 13-71), respectively. Numbers of performed first-line susceptibility tests varied between 3 and 1400 (median 36, IQR 28-78). Eight laboratories performed DST for NTM. Also, 26.9% of all laboratories did not offer rapid genotypic DST (gDST) from primary samples.CONCLUSION: The landscape of diagnostic mycobacteriology in Germany is highly heterogenic with considerable variations in sample numbers and testing methodologies. Shortcomings exist with respect to fluorochrome staining of primary samples, rapid gDST of MTBC, and DST of NTM. National guidelines need to be adapted accordingly.

Differential drug susceptibility patterns of Mycobacterium chimaera and other members of the Mycobacterium avium-intracellulare complex.

OBJECTIVES: To determine MIC distributions for Mycobacterium chimaera, Mycobacterium intracellulare, Mycobacterium colombiense and Mycobacterium avium, and to derive tentative epidemiological cut-off (ECOFF) values. METHODS: A total of 683 bacterial isolates (M. chimaera, n = 203; M. intracellulare, n = 77; M. colombiense, n = 68; M. avium, n = 335) from 627 patients were tested by broth microdilution according to CLSI protocol M24-A2 on Sensititre RAPMYCOI plates. MICs were interpreted based on CLSI breakpoints for clarithromycin, and tentative breakpoints for amikacin, moxifloxacin and linezolid. Tentative ECOFFs were determined by visual approximation and the ECOFFinder algorithm. RESULTS: Modal MIC, MIC50 and MIC90 values were within ± one dilution step from the respective aggregated data set for 47/48 (97.9%), 48/48 (100%) and 48/48 (100%) species-drug combinations. Clarithromycin wild-type populations were mostly classified as susceptible (MIC90 4-8 mg/L; S ≤8 mg/L). Rifabutin MICs were lower than those of rifampicin. Tentative moxifloxacin, linezolid and amikacin breakpoints split wild-type populations. No ECOFFs could be set for rifampicin, ethambutol, ciprofloxacin, isoniazid, trimethoprim/sulfamethoxazole and doxycycline because of truncation of MIC distributions. Agreement between the visually determined and the modelled 97.5% ECOFFs was 90.9%. All 99.0% ECOFFs were one titre step higher than by visual approximation. CONCLUSIONS: Drug susceptibility patterns of M. chimaera are comparable to those of closely related species. Except for clarithromycin, breakpoints for Mycobacterium avium-intracellulare complex should be re-evaluated. Statistical determination of the 99.0% ECOFF may be superior to visual approximation.

[Dying at Life's Beginning]. / Sterben am Lebensanfang.

AIM: When parents-to-be are faced with a terminal prenatal diagnosis, they are confronted with the decision either to continue the pregnancy or to terminate it at an advanced stage. This difficult decision is intimately affected by the experience of the inevitability of loss, and ethical dilemmas posed in this usually completely unexpected situation. Studies indicate that perinatal child loss due to lethal foetal anomalies is a major life event and a source of serious psychological issues, which can last for many years after the experience. Moreover, it has been shown that care for bereaved parents, if guided by their needs, can ease their burden, regardless of whether they choose to end or continue the pregnancy. The aim of this study is to inspect current practices of counselling and support of affected families and develop practical guidelines for health and social professionals involved. METHODS: A sample of 32 parents in the German-speaking part of Switzerland was investigated between December 2012 and March 2014. Semi-structured problem-centred interviews were conducted, transcribed verbatim and thematically analysed. RESULTS: 4 main time periods and 6 themes were identified by participants ranging from diagnosis until birth: "shock", "choices and dilemmas", "taking responsibility", "still being pregnant", "saying goodbye/letting go" and "planning the future". However, findings reflect critical points of care and showed gaps not only between emphasising time periods but also between affected parents' and involved professionals' views. This article reports the findings from the parents. CONCLUSION: This study provided new insights into parental responses when they are confronted with a fatal prenatal diagnosis. The results contribute towards rethinking current practices in midwifery and other healthcare during pregnancy, birth and puerperium as well as the palliative care of the child.

[Advances in diagnostic microbiology : Opportunities and limitations]. / Neue mikrobiologische Diagnostikverfahren : Chancen und Limitierungen.

In the light of ever increasing problems related to the emergence of multidrug-resistant bacteria, rapid microbiological diagnostics are of growing importance. Timely pathogen detection and availability of susceptibility data are essential for optimal treatment, but are even more crucial for de-escalation of broad spectrum empiric therapies. Medical microbiology is, thus, an integral part of antimicrobial stewardship programs. Traditional microbiological techniques for species identification and susceptibility testing rely on bacterial growth and are, thus, characterized by inherent slowness. Time-to-report is usually 48 h or longer, and typically delays optimization of therapeutic regimens. Constant improvement of available techniques (e. g., molecular methods) and introduction of novel methods (e. g., matrix-assisted laser desorption ionization time-of-flight [MALDI-ToF] mass spectrometry) have fundamentally changed diagnostic procedures. As a consequence, sensitivity and specificity as well as time-to-report have been dramatically improved. In this manuscript, key methodological advances in medical microbiology are discussed, emphasizing consequences for daily management of infectious disease patients.

Adherence of volatile propofol to various types of plastic tubing.

Propofol is an intravenous anesthetic. Currently, it is not possible to routinely measure blood concentration of the drug in real time. However, multi-capillary column ion-mobility spectrometry of exhaled gas can estimate blood propofol concentration. Unfortunately, adhesion of volatile propofol on plastic materials complicates measurements. Therefore, it is necessary to consider the extent to which volatile propofol adheres to various plastics used in sampling tubing. Perfluoralkoxy (PFA), polytetrafluorethylene (PTFE), polyurethane (PUR), silicone, and Tygon tubing were investigated in an experimental setting using a calibration gas generator (HovaCAL). Propofol gas was measured for one hour at 26 °C, 50 °C, and 90 °C tubing temperature. Test tubing segments were then flushed with N2 to quantify desorption. PUR and Tygon sample tubing absorbed all volatile propofol. The silicone tubing reached the maximum propofol concentration after 119 min which was 29 min after propofol gas exposure stopped. The use of PFA or PTFE tubing produced comparable and reasonably accurate propofol measurements. The desaturation time for the PFA was 10 min shorter at 26 °C than for PTFE. PFA tubing thus seems most suitable for measurement of volatile propofol, with PTFE as an alternative.

Influence of the respirator on volatile organic compounds: an animal study in rats over 24 hours.

Long-term animal studies are needed to accomplish measurements of volatile organic compounds (VOCs) for medical diagnostics. In order to analyze the time course of VOCs, it is necessary to ventilate these animals. Therefore, a total of 10 male Sprague-Dawley rats were anaesthetized and ventilated with synthetic air via tracheotomy for 24 h. An ion mobility spectrometry coupled to multi-capillary columns (MCC-IMS) was used to analyze the expired air. To identify background contaminations produced by the respirator itself, six comparative measurements were conducted with ventilators only. Overall, a number of 37 peaks could be detected within the positive mode. According to the ratio peak intensity rat/ peak intensity ventilator blank, 22 peaks with a ratio >1.5 were defined as expired VOCs, 12 peaks with a ratio between 0.5 and 1.5 as unaffected VOCs, and three peaks with a ratio <0.5 as resorbed VOCs. The peak intensity of 12 expired VOCs changed significantly during the 24 h measurement. These results represent the basis for future intervention studies. Notably, online VOC analysis with MCC-IMS is possible over 24 h in ventilated rats and allows different experimental approaches.

Wash-out of ambient air contaminations for breath measurements.

In breath analysis, ambient air contaminations are ubiquitous and difficult to eliminate. This study was designed to investigate the reduction of ambient air background by a lung wash-out with synthetic air. The reduction of the initial ambient air volatile organic compound (VOC) intensity was investigated in the breath of 20 volunteers inhaling synthetic air via a sealed full face mask in comparison to inhaling ambient air. Over a period of 30 minutes, breath analysis was conducted using ion mobility spectrometry coupled to a multi-capillary column. A total of 68 VOCs were identified for inhaling ambient air or inhaling synthetic air. By treatment with synthetic air, 39 VOCs decreased in intensity, whereas 29 increased in comparison to inhaling ambient air. In total, seven VOCs were significantly reduced (P-value < 0.05). A complete wash-out of VOCs in this setting was not observed, whereby a statistically significant reduction up to 65% as for terpinolene was achieved. Our setting successfully demonstrated a reduction of ambient air contaminations from the airways by a lung wash-out with synthetic air.

Multi-capillary column-ion mobility spectrometer (MCC-IMS) breath analysis in ventilated rats: a model with the feasibility of long-term measurements.

Rats are commonly used in medical research as they enable a high grade of standardization. The exhalome of ventilated rats has not as yet been investigated using an ion mobility spectrometer coupled with a multi-capillary column (MCC-IMS). As a first step, a rat model has to be established to measure potential biomarkers in the exhale with long-term settings, allowing constant and continuous analysis of exhaled air in time series. Therefore, eight animals were anaesthetized, prepared and ventilated for 1 h. A total of 73 peaks were directly detected with the IMS chromatogram. Thirty five of them were assigned to the ventilator system and 38 to the animals. Peak intensity varied within three measurements. The intensity of analytes of individual rats varied by a factor of up to 18. This new model will also enable continuous measurements of volatile organic compounds (VOCs) from rat's breath in long-term experiments. It is hoped that, in the future, variability and progression of VOCs can be monitored in different models of diseases using this set-up.

Free volume dilatation in polymers by ortho-positronium.

The possibility of positronium induced free volume cavity expansion in some polymers above the glass transition temperature was investigated using experimental positron annihilation lifetime data from the literature for polydimethylsiloxane, polyisobutylene, and polybutadiene as function of temperature. The results suggest that free volume sites can expand towards an equilibrium size, determined as the equilibrium Ps-bubble size defined earlier for low-molecular-weight liquids. The expansion can be explained by the increase of molecular mobility and hence decrease of relaxation times, which at the higher temperatures approach the o-Ps lifetimes. Nanoscale viscosities were estimated using Navier-Stokes equation and were found to be several orders of magnitude lower than the macroscopic viscosity at the same temperature.

[Splenic injury as complication of thoracoscopic-assisted ventral stabilisation of thoracolumbar vertebral body fractures - report of two cases]. / Milzverletzung als Komplikation der thorakoskopisch assistierten ventralen Stabilisierung von thorakolumbalen Wirbelkörperfrakturen - 2 Fallberichte.

Minimally invasive procedures for additive ventral stabilisation of dorsal instrumented unstable burst fractures of the thoracolumbar spine have been developed. Typical complications of these standardised techniques have been described in the past. Only limited data exist on injury to upper abdominal organs associated with minimally invasive spondylodesis. We report two cases of splenic injury after thoracoscopic-assisted ventral stabilisation of incomplete burst fractures. Retraction of the diaphragm might be the main factor causing this complication. In conclusion, splenic injury is a rare but potentially lethal complication in the operative treatment of thoracolumbar fractures. Therefore postoperative abdominal sonography should routinely be done and in case of haemodynamic instability the possibility of splenic injury must be considered as part of the differential diagnosis.

Microbialites and global environmental change across the Permian-Triassic boundary: a synthesis.

Permian-Triassic boundary microbialites (PTBMs) are thin (0.05-15 m) carbonates formed after the end-Permian mass extinction. They comprise Renalcis-group calcimicrobes, microbially mediated micrite, presumed inorganic micrite, calcite cement (some may be microbially influenced) and shelly faunas. PTBMs are abundant in low-latitude shallow-marine carbonate shelves in central Tethyan continents but are rare in higher latitudes, likely inhibited by clastic supply on Pangaea margins. PTBMs occupied broadly similar environments to Late Permian reefs in Tethys, but extended into deeper waters. Late Permian reefs are also rich in microbes (and cements), so post-extinction seawater carbonate saturation was likely similar to the Late Permian. However, PTBMs lack widespread abundant inorganic carbonate cement fans, so a previous interpretation that anoxic bicarbonate-rich water upwelled to rapidly increase carbonate saturation of shallow seawater, post-extinction, is problematic. Preliminary pyrite framboid evidence shows anoxia in PTBM facies, but interbedded shelly faunas indicate oxygenated water, perhaps there was short-term pulsing of normally saturated anoxic water from the oxygen-minimum zone to surface waters. In Tethys, PTBMs show geographic variations: (i) in south China, PTBMs are mostly thrombolites in open shelf settings, largely recrystallised, with remnant structure of Renalcis-group calcimicrobes; (ii) in south Turkey, in shallow waters, stromatolites and thrombolites, lacking calcimicrobes, are interbedded, likely depth-controlled; and (iii) in the Middle East, especially Iran, stromatolites and thrombolites (calcimicrobes uncommon) occur in different sites on open shelves, where controls are unclear. Thus, PTBMs were under more complex control than previously portrayed, with local facies control playing a significant role in their structure and composition.