Influence of Covid-19 disease on hemostasis dynamics during extracorporeal membrane oxygenation (ECMO)1

INTRODUCTION

COVID-19 causes a considerable degradation of pulmonary function to the point of an acute respiratory distress syndrome (ARDS). Over the course of the disease the gas exchange capability of the lung can get impaired to such an extent that extracorporeal membrane oxygenation (ECMO) is needed as a life-saving intervention. In patients COVID-19 as well as ECMO may cause severe coagulopathies which manifest themselves in micro and macro thrombosis. Previous studies established D-dimers as a marker for critical thrombosis of the ECMO system while on admission increased D-dimers are associated with a higher mortality in COIVD-19 patients. It is therefore crucial to determine if COVID-19 poses an increased risk of early thrombosis of the vital ECMO system.

METHODS

40 patients who required ECMO support were enrolled in a retrospective analysis and assigned into 2 groups. The COVID group consist of 20 COVID-19 patients who required ECMO support (n = 20), whereas 20 ECMO patients without COVID-19 were assigned to the control group. D-dimers, fibrinogen, antithrombin III (AT III), lactate dehydrogenase (LDH) and platelet count were analysed using locally weighted scatterplot smoothing and MANOVAs.

RESULTS

The analysis of both groups shows highly significant differences in the dynamics of hemostasis. The increase in D-dimers that is associated with thrombosis of the ECMO systems occurs in COVID-19 patients around 2 days earlier (p = 2,8115 10-11) while fibrinogen is consumed steadily. In the control group fibrinogen levels increase rapidly after ten days with a plateau phase of around five days (p = 1,407 10-3) . Both groups experience a rapid increase in AT III after start of support by ECMO (p = 5,96 10-15). In the COVID group platelet count decreased from 210 giga/l to 130 giga/l within eight days, while in the same time span in the control group platelets decreased from 180 giga/l to 105 giga/l (p = 1,1 10-15). In both groups a marked increase in LDH beyond 5000 U/l occurs (p = 3,0865 10-15).

CONCLUSION

The early increase in D-dimers and decrease in fibrinogen suggests that COVID-19 patients bear an increased risk of early thrombosis of the ECMO system compared to other diseases treated with ECMO. Additionally, the control group shows signs of severe inflammation 10 days after the start of ECMO which were absent in COVID-19 patients.

Longitudinal analysis of external quality assessment of immunoassay-based steroid hormone measurement indicates potential for improvement in standardization

As hormonal disorders are linked to several diseases, the accurate quantitation of steroid hormone levels in serum is crucial in order to provide patients with a reliable diagnosis. Mass spectrometry-based methods are regarded as having the highest level of specificity and sensitivity. However, immunoassays are more commonly used in routine diagnostics to measure steroid levels as they are more cost effective and straightforward to conduct. This study analyzes the external quality assessment results for the measurement of testosterone, progesterone and 17β-estradiol in serum using immunoassays between early 2020 and May 2022. As reference measurement procedures are available for the three steroid hormones, the manufacturer-specific biases were normalized to the reference measurement values. The manufacturer-specific coefficients of variation were predominantly inconspicuous, below 20% for the three hormones when outliers are disregarded, however there were large differences between the various manufacturer collectives. For some collectives, the median bias to the respective reference measurement value was repeatedly greater than ±35%, which is the acceptance limit defined by the German Medical Association. In the case of testosterone and progesterone determination, some collectives tended to consistently over- or underestimate analyte concentrations compared to the reference measurement value, however, for 17β-estradiol determination, both positive and negative biases were observed. This insufficient level of accuracy suggests that cross-reactivity continues to be a fundamental challenge when antibody detection is used to quantify steroids with a high structural similarity. Distinct improvements in standardization are required to provide accurate analysis and thus, reliable clinical interpretations. The increased accuracy of the AX immunoassay for testosterone measurement, as observed in the INSTAND EQAs between 2020 and 2022, could be the result of a recalibration of the assay and raises hope for further improvement of standardization of immunoassay-based steroid hormone analyses in the coming years.

Prospective clinical study testing the efficacy and safety of a new formula to increase the precision of oxygen therapy in the initiation phase of cardiopulmonary bypass

INTRODUCTION

During cardiopulmonary bypass (CPB), supranormal concentrations of oxygen are routinely administered with the intention to prevent cellular hypoxia. However, hyperoxemia may have adverse effects on patient outcome. Oxygen settings are based on the perfusionist's individual work experience rather than profound recommendations and studies analyzing the effect of oxygen levels are in need of methodological improvement. We aimed to advance perfusion technique by developing and clinically applying a formula for tailored oxygen therapy in CPB.

METHODS

A formula to precalculate the oxygenator setting before CPB was developed. The newly-derived formula was then evaluated in a prospective, single-center pilot study to test whether a predefined arterial partial oxygen pressure (PaO2) of 150-250 mmHg could be reached. 80 patients were enrolled in the study between April and September 2021.

RESULTS

The mean oxygen fraction calculated for the setting of the gas blender was 52% ±0,12. The mean PaO2 after initiation of the CPB was 193 ± 99 mmHg (min-max: 61-484, median 163 mmHg). 38.75% of the values were in the desired PaO2 corridor of 150 to 250 mmHg. 8.75% of all PaO2 values were below <79.9 mmHg, 31.25% between 80 and 149.9 mmHg, 38.75% between 150 and 249.9 mmHg and 21.25%>250 mmHg.

CONCLUSIONS

Conceptually, perfusion technique should be goal-directed, guided by objective parameters and formulas. Although the optimal CPB oxygenation target remains unknown, it is nevertheless important to develop strategies to tailor oxygen therapy to aid in creating evidence as to what level of oxygen is best for patients during CPB. The formula we derived needs further adjustments to increase results in the target range.

Improving Diastolic and Microvascular Function in Heart Transplantation with Donation after Circulatory Death

The impact of the machine perfusion of donation after circulatory death (DCD) hearts with the novel Custodiol-N solution on diastolic and coronary microvascular dysfunction is unknown. Porcine DCD-hearts were maintained four hours by perfusion with normothermic blood (DCD-B), hypothermic Custodiol (DCD-C), or Custodiol-N (DCD-CN), followed by one hour of reperfusion with fresh blood, including microvascular and contractile evaluation. In another group (DCD group), one hour of reperfusion, including microvascular and contractile evaluation, was performed without a previous maintenance period (all groups N = 5). We measured diastolic function with a balloon catheter and microvascular perfusion by Laser-Doppler-Technology, resulting in Laser-Doppler-Perfusion (LDP). We performed immunohistochemical staining and gene expression analysis. The developed pressure was improved in DCD-C and DCD-CN. The diastolic pressure decrement (DCD-C: -1093 ± 97 mmHg/s; DCD-CN: -1703 ± 329 mmHg/s; DCD-B: -690 ± 97 mmHg/s; p < 0.05) and relative LDP (DCD-CN: 1.42 ± 0.12; DCD-C: 1.11 ± 0.13; DCD-B: 1.22 ± 0.27) were improved only in DCD-CN. In DCD-CN, the expression of eNOS increased, and ICAM and VCAM decreased. Only in DCD-B compared to DCD, the pathways involved in complement and coagulation cascades, focal adhesion, fluid shear stress, and the IL-6 and IL-17 pathways were upregulated. In conclusion, machine perfusion with Custodiol-N improves diastolic and microvascular function and preserves the microvascular endothelium of porcine DCD-hearts.

Role of Lp(a) in patients with erectile dysfunction undergoing angioplasty for symptomatic pelvic artery disease

Background: Atherosclerotic disease of erection-related arteries is a major reason for erectile dysfunction (ED). Lp(a) has been implied in the pathophysiology of atherosclerosis in the coronary and lower limb arteries. Here, we investigated if Lp(a) plays a specific role in ED due with symptomatic pelvic artery atherosclerosis. Patients and methods: Out of 276 consecutive patients treated for ED with angioplasties on proximal (69%) and distal (31%, distal to Alcock channel) erection-related arteries, 236 patients (age: 62±10 years) of which Lp(a) values were available were retrospectively analyzed. Results: The baseline International Index of Erectile Function-15 (IIEF-15) score was 29±15 and significantly increased to 43±20 (increase: 14±21) after treatment at average follow up of 286±201 days. In 25%, Lp(a) values were elevated to more than 30 mg/dL. Hypercholesterolemia, coronary, lower extremity peripheral, and polyvascular disease were more common in patients with Lp(a) ≥60 mg/dl. Anatomic arterial lesion distribution (proximal/distal), improvement in IIEF-15 and clinically driven re-intervention rate (overall 7%) did not differ between patients with <30, 30-59, and ≥60 mg/dL Lp(a). Conclusions: While angioplasty is an effective therapy for ED of arterial origin in patients with obstruction of erection-related arteries, Lp(a) does not seem to play a major role for clinical outcomes in these patients.

Prediction Model for Contractile Function of Circulatory Death Donor Hearts Based on Microvascular Flow Shifts During Ex Situ Hypothermic Cardioplegic Machine Perfusion

Background Hearts procured from circulatory death donors (DCD) are predominantly maintained by machine perfusion (MP) with normothermic donor blood. Currently, DCD heart function is evaluated by lactate and visual inspection. We have shown that MP with the cardioplegic, crystalloid Custodiol-N solution is superior to blood perfusion to maintain porcine DCD hearts. However, no method has been developed yet to predict the contractility of DCD hearts after cardioplegic MP. We hypothesize that the shift of microvascular flow during continuous MP with a cardioplegic preservation solution predicts the contractility of DCD hearts. Methods and Results In a pig model, DCD hearts were harvested and maintained by MP with hypothermic, oxygenated Custodiol-N for 4 hours while myocardial microvascular flow was measured by Laser Doppler Flow (LDF) technology. Subsequently, hearts were perfused with blood for 2 hours, and left ventricular contractility was measured after 30 and 120 minutes. Various novel parameters which represent the LDF shift were computed. We used 2 combined LDF shift parameters to identify bivariate prediction models. Using the new prediction models based on LDF shifts, highest r² for end-systolic pressure was 0.77 (P=0.027), for maximal slope of pressure increment was 0.73 (P=0.037), and for maximal slope of pressure decrement was 0.75 (P=0.032) after 30 minutes of reperfusion. After 120 minutes of reperfusion, highest r² for end-systolic pressure was 0.81 (P=0.016), for maximal slope of pressure increment was 0.90 (P=0.004), and for maximal slope of pressure decrement was 0.58 (P=0.115). Identical prediction models were identified for maximal slope of pressure increment and for maximal slope of pressure decrement at both time points. Lactate remained constant and therefore was unsuitable for prediction. Conclusions Contractility of DCD hearts after continuous MP with a cardioplegic preservation solution can be predicted by the shift of LDF during MP.

Cytokine Adsorber Use during DCD Heart Perfusion Counteracts Coronary Microvascular Dysfunction

Microvascular dysfunction (MVD) in cardiac allografts is associated with an impaired endothelial function in the coronary microvasculature. Ischemia/reperfusion injury (IRI) deteriorates endothelial function. Hearts donated after circulatory death (DCD) are exposed to warm ischemia before initiating ex vivo blood perfusion (BP). The impact of cytokine adsorption during BP to prevent MVD in DCD hearts is unknown. In a porcine DCD model, we assessed the microvascular function of hearts after BP with (DCD-BPCytoS, n = 5) or without (DCD-BP, n = 5) cytokine adsorption (CytoSorb®). Microvascular autoregulation was assessed by increasing the coronary perfusion pressure, while myocardial microcirculation was measured by Laser-Doppler-Perfusion (LDP). We analyzed the immunoreactivity of arteriolar oxidative stress markers nitrotyrosine and 4-hydroxy-2-nonenal (HNE), endothelial injury indicating cell adhesion molecules CD54, CD106 and CD31, and eNOS. We profiled the concentration of 13 cytokines in the perfusate. The expression of 84 genes was determined and analyzed using machine learning and decision trees. Non-DCD hearts served as a control for the gene expression analysis. Compared to DCD-BP, relative LDP was improved in the DCD-BPCytoS group (1.51 ± 0.17 vs. 1.08 ± 0.17). Several pro- and anti-inflammatory cytokines were reduced in the DCD-BPCytoS group. The expression of eNOS significantly increased, and the expression of nitrotyrosine, HNE, CD54, CD106, and CD31, markers of endothelial injury, majorly decreased in the DCD-BPCytoS group. Three genes allowed exact differentiation between groups; regulation of HIF1A enabled differentiation between perfusion (DCD-BP, DCD-BPCytoS) and non-perfusion groups. CAV1 allowed differentiation between BP and BPCytoS. The use of a cytokine adsorption device during BP counteracts preload-dependent MVD and preserves the microvascular endothelium by preventing oxidative stress and IRI of coronary arterioles of DCD hearts.

[Improved quality of stored packed red blood cells by mechanical rinsing]

BACKGROUND

The transfusion of packed red blood cells (PRBC) is associated with various side effects, including storage damage to PRBCs. The cells change their structure, releasing potassium as well as lactate. Mechanical rinsing, available in many hospitals, is able to remove toxic substances and possibly minimizes the negative side effects of transfusion.

OBJECTIVE

The primary aim of our study was to improve the quality of PRBCs before transfusion. The effects of different washing solutions on PRBC quality were analyzed.

MATERIAL AND METHODS

This in vitro study compares 30 mechanically washed PRBCs. They were either processed with standard normal saline 0.9% (n = 15, N group) or a hemofiltration solution containing 4 mmol/l potassium (n = 15, HF group) by a mechanical rinsing device (Xtra, LivaNova, Munich, Germany). A subgroup analysis was performed based on the storage duration of the processed PRBCs (7, 14, 37 days). Samples were taken before washing (EKprä), immediately after washing (EKpost) and 10 h later (EKpost10h), after storage in the "wash medium" at room temperature. Concentrations of ATP (probability of survival in transfused erythrocytes), lactate, citrate and electrolytes (potassium, sodium, chloride, calcium) were tested.

RESULTS AND CONCLUSION

Mechanical rinsing improves pretransfusion quality of PRBC. Washing with a hemofiltration solution results in a more physiological electrolyte composition. Even 10 h after mechanical rinsing with a hemofiltration solution, the quality of 37-day-old PRBC is comparable to young PRBC that have been stored for 7 days and have not been washed. Washing stored PRBC increases the ATP content, which subsequently leads to an increased probability of survival of red cells after transfusion.

Genotyping of familial Mediterranean fever gene (MEFV)-Single nucleotide polymorphism-Comparison of Nanopore with conventional Sanger sequencing

Background

Through continuous innovation and improvement, Nanopore sequencing has become a powerful technology. Because of its fast processing time, low cost, and ability to generate long reads, this sequencing technique would be particularly suitable for clinical diagnostics. However, its raw data accuracy is inferior in contrast to other sequencing technologies. This constraint still results in limited use of Nanopore sequencing in the field of clinical diagnostics and requires further validation and IVD certification.

Methods

We evaluated the performance of latest Nanopore sequencing in combination with a dedicated data-analysis pipeline for single nucleotide polymorphism (SNP) genotyping of the familial Mediterranean fever gene (MEFV) by amplicon sequencing of 47 clinical samples. Mutations in MEFV are associated with Mediterranean fever, a hereditary periodic fever syndrome. Conventional Sanger sequencing, which is commonly applied in clinical genetic diagnostics, was used as a reference method.

Results

Nanopore sequencing enabled the sequencing of 10 target regions within MEFV with high read depth (median read depth 7565x) in all samples and identified a total of 435 SNPs in the whole sample collective, of which 29 were unique. Comparison of both sequencing workflows showed a near perfect agreement with no false negative calls. Precision, Recall, and F1-Score of the Nanopore sequencing workflow were > 0.99, respectively.

Conclusions

These results demonstrated the great potential of current Nanopore sequencing for application in clinical diagnostics, at least for SNP genotyping by amplicon sequencing. Other more complex applications, especially structural variant identification, require further in-depth clinical validation.

A novel heat treatment protocol for human milk

Human milk (HM) is the recommended nutrition for premature infants, but it may require processing to ensure microbial safety. The current standard is Holder pasteurisation (HoP), i.e. heating milk at 62.5 ± 0.5°C for 30 min, which eliminates bacteria but destroys heat labile bioactive HM components. We aimed to test an alternative thermal method, high-temperature short-time (HTST) pasteurisation using a modified Holder pasteurisation platform as this method has shown to preserve proteins in experimental HM flow pasteurisers. We analysed the ability of this batch process to eliminate bacterial species and to retain alkaline phosphatase, secretory immunoglobulin A and lactoferrin in HM. HTST at 81°C/5 s was as effective as HoP in bacterial count reduction while the retention of bioactive components was only improved at 62°C/5 s as compared to 72°C/5 s and HoP. HTST is a promising alternative to HoP but an optimal temperature-time combination needs to be determined for each technical platform separately.

Holder Pasteurization: Comparison of Water-Bath and Dry-Tempering Devices

BACKGROUND

Human milk (HM) for premature infants is frequently Holder pasteurized (heated at 62.5 ± 0.5°C for 30 min) despite its detrimental effects on heat-sensitive milk components. This tolerated compromise ensures HM's microbial safety while less detrimental methods like short-time HM treatments (HTST) are still being evaluated. Dry-tempering devices (DT-HoP) were recently introduced in clinical practice due to hygienic concerns about water-based Holder pasteurizers (WB-HoP). Evidence on the impact of such dry-tempering devices on HM quality is lacking. The aim of this study was to compare protein retention rates after DT-HoP, WB-HoP and HTST.

METHODS

We colorimetrically determined alkaline phosphatase activity (ALP), concentrations of secretory immunoglobulin A (sIgA), and lactoferrin (LF) before and after DT-HoP, WB-HoP and HTST.

RESULTS

ALP was below the detection limit after HoP, but retained 52.8 ± 13% activity after HTST (p < 0.01). Secretory IgA (WB-HoP = 73.2 ± 13.5% vs. DT-HoP = 57 ± 14%, p = 0.0018) and LF retention (WB-HoP=47 ± 40% vs. DT-HoP=25 ± 8%, p = 0.07) differed between the two HoP modes. Again, retention was better maintained after HTST compared to HoP (80.4 ± 23% sIgA and 70 ± 42% LF concentration, all p < 0.01).

CONCLUSION

Dry-tempering milk lowers even further the quality of HM when performing HoP compared to water-bath pasteurization, while HTST warrants continued evaluation for clinical application.

Differences Between MR Brain Region Segmentation Methods: Impact on Single-Subject Analysis

For the segmentation of magnetic resonance brain images into anatomical regions, numerous fully automated methods have been proposed and compared to reference segmentations obtained manually. However, systematic differences might exist between the resulting segmentations, depending on the segmentation method and underlying brain atlas. This potentially results in sensitivity differences to disease and can further complicate the comparison of individual patients to normative data. In this study, we aim to answer two research questions: 1) to what extent are methods interchangeable, as long as the same method is being used for computing normative volume distributions and patient-specific volumes? and 2) can different methods be used for computing normative volume distributions and assessing patient-specific volumes? To answer these questions, we compared volumes of six brain regions calculated by five state-of-the-art segmentation methods: Erasmus MC (EMC), FreeSurfer (FS), geodesic information flows (GIF), multi-atlas label propagation with expectation–maximization (MALP-EM), and model-based brain segmentation (MBS). We applied the methods on 988 non-demented (ND) subjects and computed the correlation (PCC-v) and absolute agreement (ICC-v) on the volumes. For most regions, the PCC-v was good (>0.75), indicating that volume differences between methods in ND subjects are mainly due to systematic differences. The ICC-v was generally lower, especially for the smaller regions, indicating that it is essential that the same method is used to generate normative and patient data. To evaluate the impact on single-subject analysis, we also applied the methods to 42 patients with Alzheimer’s disease (AD). In the case where the normative distributions and the patient-specific volumes were calculated by the same method, the patient’s distance to the normative distribution was assessed with the z-score. We determined the diagnostic value of this z-score, which showed to be consistent across methods. The absolute agreement on the AD patients’ z-scores was high for regions of thalamus and putamen. This is encouraging as it indicates that the studied methods are interchangeable for these regions. For regions such as the hippocampus, amygdala, caudate nucleus and accumbens, and globus pallidus, not all method combinations showed a high ICC-z. Whether two methods are indeed interchangeable should be confirmed for the specific application and dataset of interest.

Comparative analysis of alignment tools for application on Nanopore sequencing data

INTRODUCTION: Long-read sequencing techniques such as Oxford Nanopore sequencing, are representing a promising novel approach in molecular-biological methodology, enabling potential facilitation in mapping and de novo assembly. In comparison to conventional sequencing methods, novel alignment tools are mandated to compensate differing data structures (especially high error rate) to achieve acceptably accurate analysis results. METHODS: In this study, benchmarking for long read aligners BLASR, GraphMap, LAST, minimap2, NGMLR and the short-read aligner BWA MEM on three experimental datasets was conducted. Obtained alignment results were compared for various quality and performance criteria, such as match rate, mismatch rate, error rate, working memory usage and computational time. RESULTS: The comparison yielded differences in alignment quality and performance of tools under test. Tool LAST showed the largest differences among all tools. Minimap2 achieved constant quality with good performance. BLASR, GraphMap, BWA MEM and NGMLR showed slight differences only. CONCLUSION: Differences among the tools could be reasoned with dataset characteristics and algorithm approaches of individual tools. All tools except BLASR seem applicable for Nanopore sequencing data. Therefore, selection of the tool should be done under consideration of the experimental design and the further downstream analysis

Relationship of Laser-Doppler-Flow and coronary perfusion and a concise update on the importance of coronary microcirculation in donor heart machine perfusion

BACKGROUND

Machine perfusion (MP) is a novel method for donor heart preservation. The coronary microvascular function is important for the transplantation outcome. However, current research on MP in heart transplantation focuses mainly on contractile function.

OBJECTIVE

We aim to present the application of Laser-Doppler-Flowmetry to investigate coronary microvascular function during MP. Furthermore, we will discuss the importance of microcirculation monitoring for perfusion-associated studies in HTx research.

METHODS

Porcine hearts were cardioplegically arrested and harvested (Control group, N = 4). In an ischemia group (N = 5), we induced global ischemia of the animal by the termination of mechanical ventilation before harvesting. All hearts were mounted on an MP system for blood perfusion. After 90 minutes, we evaluated the effect of coronary perfusion pressures from 20 to 100 mmHg while coronary laser-doppler-flow (LDF) was measured.

RESULTS

Ischemic hearts showed a significantly decreased relative LDF compared to control hearts (1.07±0.06 vs. 1.47±0.15; p = 0.034). In the control group, the coronary flow was significantly lower at 100 mmHg of perfusion pressure than in the ischemia group (895±66 ml vs. 1112±32 ml; p = 0.016).

CONCLUSIONS

Laser-Doppler-Flowmetry is able to reveal coronary microvascular dysfunction during machine perfusion of hearts and is therefore of substantial interest for perfusion-associated research in heart transplantation.

Serological and viral genetic features of patients with COVID-19 in a selected German patient cohort-correlation with disease characteristics

To study host-virus interactions after SARS coronavirus-2 (SARS-CoV-2) infection, genetic virus characteristics and the ensued humoral immune response were investigated for the first time. Fifty-five SARS-CoV-2-infected patients from the early pandemic phase were followed up including serological testing and whole genome sequencing. Anti-spike and nucleocapsid protein (S/N) IgG and IgM levels were determined by screening ELISA and IgG was further characterized by reactivity to S-subunit 1 (anti-S1), S-subunit 2 (anti-S2) and anti-N. In 55 patients, 90 genetic SARS-CoV-2 changes including 48 non-synonymous single nucleotide variants were identified. Phylogenetic analysis of the sequencing data showed a cluster representing a local outbreak and various family clusters. Anti-S/N and anti-N IgG were detected in 49 patients at an average of 83 days after blood collection. Anti-S/N IgM occurred significantly less frequently than IgG whereas anti-S2 was the least prevalent IgG reactivity (P < 0.05, respectively). Age and overweight were significantly associated with higher anti-S/N and anti-S1 IgG levels while age only with anti-N IgG (multiple regression, P < 0.05, respectively). Anti-S/N IgG/IgM levels, blood group A + , cardiovascular and tumour disease, NSP12 Q444H and ORF3a S177I were independent predictors of clinical characteristics with anti-S/N IgM being associated with the need for hospitalization (multivariate regression, P < 0.05, respectively). Anti-SARS-CoV-2 antibody generation was mainly affected by higher age and overweight in the present cohort. COVID-19 traits were associated with genetic SARS-CoV-2 variants, anti-S/N IgG/IgM levels, blood group A + and concomitant disease. Anti-S/N IgM was the only antibody associated with the need for hospitalization.

Reconditioning of circulatory death hearts by ex-vivo machine perfusion with a novel HTK-N preservation solution

BACKGROUND

Warm ischemia followed by blood reperfusion is associated with reduced myocardial contractility. Circulatory death (CD) hearts are maintained by machine perfusion (MP) with blood. However, the impact of MP with histidine-tryptophane-ketoglutarate (HTK) or novel HTK-N solution on reconditioning of CD-heart contractility is unknown.

METHODS

In a porcine model, native hearts were directly harvested (control), or CD was induced before harvesting, followed by left ventricular (LV) contractile assessment. In MP-groups, CD-hearts were maintained for 4 h by MP with blood (CD-B), cold oxygenated HTK (CD-HTK) or HTK-N (CD-HTK-N) before contractile evaluation (all groups n = 8). We performed immunohistochemistry of LV myocardial samples. We profiled myocardial expression of 84 oxidative stress-related genes and correlated the findings with myocardial contractility via a machine learning algorithm.

RESULTS

HTK-N improved end-systolic pressure (ESP=172±10 vs 132±5 mmHg, p = 0.02) and maximal slope of pressure increment (dp/dt_max=2161±214 vs 1240±167 mmHg/s, p = 0.005) compared to CD, whereas CD-B failed to improve contractility. Dp/dt_max (2161±214 vs 1177±156, p = 0.08) and maximal rate of pressure decrement (dp/dt_min=-1501±228 vs -637±79, p = 0.005) were also superior in CD-HTK-N compared to CD-B. In CD-HTK-N, myocardial 4-hydroxynonenal (marker for oxidative stress; p<0.001), nitrotyrosine (marker for nitrosative stress; p = 0.004), poly(adenosine diphosphate-ribose)polymerase (marker for necrosis; p = 0.028) immunoreactivity and cell swelling (p = 0.008) were decreased compared to CD-B. Strong correlation of gene expression with ESP was identified for oxidative stress defense genes in CD-HTK-N.

CONCLUSION

During harvesting procedure, MP with HTK-N reconditions CD-heart systolic and diastolic function by reducing oxidative and nitrosative stress and preventing cardiomyocytes from cell swelling and necrosis.

Impact of skeletonized harvesting of the internal thoracic artery on intrasternal microcirculation considering preparation quality

OBJECTIVES

Previous studies have demonstrated the impact of internal thoracic artery (ITA) harvesting on microcirculation in parasternal tissues. However, the impact of skeletonized ITA harvesting on intrasternal microcirculation is unknown. Intraskeletal tissue perfusion has been proven to be crucial for deep wound healing. Furthermore, the impact of different levels of surgical preparation quality on intrasternal microcirculation has not been investigated yet.

METHODS

Sternal microcirculation (sLDP) was monitored with a novel Laser Doppler Perfusion needle probe, while the ITA was skeletonized in a pig model. To mimic different levels of preparation quality, satellite veins were either coagulated or not during preparation. To show the effect of ideally avoiding any surgical manipulation on sLDP, the ITA was clipped in a third sham-harvested group.

RESULTS

sLDP was reduced highly significant to 71 [standard deviation (SD): 9]% (P < 0.001) after skeletonized harvesting of the ITA. Coagulation of the satellite veins as a detrimental surgical factor resulted in a significantly stronger reduction of sLDP to 56 (SD: 11)% (P < 0.05) compared to sLDP with non-coagulated satellite veins. ITA clipping reduced sLDP highly significant to 71 (SD: 8)% (P < 0.001) in the sham-operated group.

CONCLUSIONS

ITA harvesting markedly impairs microcirculation of the sternum but remains unavoidable when coronary artery bypass grafting should be performed. Nevertheless, excessive surgical damage and coagulation of satellite veins is avoidable and should be reduced to a minimum to minimize the risk of deep sternal wound healing complications.

Label-free identification and differentiation of different microplastics using phasor analysis of fluorescence lifetime imaging microscopy (FLIM)-generated data

As plastic pollution is becoming an increasing worldwide problem, a variety of different techniques for the detection and in-depth characterization of plastics, including spectroscopy and chromatography methods, were introduced to the public. Recently we presented fluorescence lifetime imaging microscopy (FLIM) a new approach for the identification and characterization of microplastics using their fluorescence lifetime (τ) for differentiation. A very powerful extension of the recently established FLIM could be phasor analysis, which allows data representation in an interactive 2D graphical phasor plot thereby enabling a global view of the fluorescence decay in each pixel of the measured image. Microplastic particles generated from six different types of plastics were subjected to excitation wavelengths of 440 nm, upon which specific fluorescence lifetimes as well as the photon yield were determined using FLIM and phasor analysis. We could show that phasor analysis for FLIM with a laser pulse repetition frequency of 40 MHz was able to generate specific locations in the phasor plot for the plastics for fast differentiation, e.g. resulting in well-defined phasor plot positions for ABS at 3.019 ns, PPE at 6.239 ns, PET bottle from Germany at 2.703 ns and PET bottle from USA at 2.711 ns. Phasor analysis for FLIM proves to be a fast, label-free, and sensitive method for the identification and differentiation of plastics also with the aid of visualization variation enabling techniques such as heat treatment of plastics.

Monitoring of perfusion quality and prediction of donor heart function during ex-vivo machine perfusion by myocardial microcirculation versus surrogate parameters

Currently, lactate (Lac) is used to evaluate machine perfusion (MP) of hearts, donated after circulatory death (DCD). We hypothesize that monitoring of myocardial microcirculation (mLDP) by Laser-Doppler-Perfusion is superior to Lac to evaluate perfusion and predict contractility. In a pig model, DCD-hearts were perfused 4 hours followed by reperfusion and left ventricular contractility measurement. Lac and mLDP were measured every 30 min in successfully (N = 9) and unsuccessfully (N = 7) maintained hearts. Successfully maintained hearts showed decreasing Lac (5.6 to 2.8 mmol/L) and slightly downregulated (92%) mLDP. In unsuccessfully maintained hearts Lac first decreased (5.1 to 3.8 mmol/L) followed by increase and mLDP dropped to 39%. In a single-variable regression only mLDP showed a significant r² for systolic (0.514, p = 0.045) and diastolic (0.501, p = 0.049) parameters. The combination of mLDP and Lac (r² = 0.876, p = 0.005) showed best results. mLDP seems to be superior to Lac to show perfusion disorders and predict DCD-heart contractility.

Using autofluorescence for microplastic detection – Heat treatment increases the autofluorescence of microplastics1

INTRODUCTION: More and more researchers are studying the effects of microplastics on the environment and the organisms living in it. Existing detection methods still require a heavy workload, complex sample preparation and high costs. In this study, autofluorescence of plastic was used as a new method for microplastic detection. MATERIAL AND METHODS: Particles of common plastics were incubated at various temperatures (21–230 °C) for different time periods to investigate the influence of these conditions on their autofluorescence using methods like fluorescence microscopy, and measurement of absorption and emission. To give an example of an autofluorescence application, ImageJ was used to determine the contamination of microplastic in sea salt samples. RESULTS: After treatment at 140 °C for 12 h the plastics ABS, PVC and PA showed a distinct increase in their fluorescence intensity. For PET higher temperatures were necessary to achieve higher fluorescence intensities. Using ImageJ, the particle contamination in sea salt samples was determined as 4903±2522 (aluminium membrane) / 5053±2167 (silicone membrane) particles in 10 g salt, which is a much higher number than counted in other publications. DISCUSSION: Probably the increase in fluorescence intensity is due to the movement of atomic bonds caused by the thermic energy during the heat treatment. The high number of counted particles by using ImageJ is most likely based on the smaller pore size of the used filter membranes and other contaminations like dust and fibers, which could be avoided by alternative sample treatment. CONCLUSION: Considering the outcomes of this study, heat treatment is a useful tool to make microplastic particles more visible in microscopic applications without readable destruction of their composition. The heat treatment of plastics for defined incubation times and temperatures can lead to a distinct increase in autofluorescence intensity of the plastics and therefore serve as an easy and cost-effective applicable method for microplastic detection.

SARS-CoV-2 antibody testing-questions to be asked

Severe acute respiratory syndrome coronavirus 2 infection and development of coronavirus disease 2019 presents a major health care challenge of global dimensions. Laboratory diagnostics of infected patients, and the assessment of immunity against severe acute respiratory syndrome coronavirus 2, presents a major cornerstone in handling the pandemic. Currently, there is an increase in demand for antibody testing and a large number of tests are already marketed or are in the late stage of development. However, the interpretation of test results depends on many variables and factors, including sensitivity, specificity, potential cross-reactivity and cross-protectivity, the diagnostic value of antibodies of different isotypes, and the use of antibody testing in identification of acutely ill patients or in epidemiological settings. In this article, the recently established COVID-19 Task Force of the German Society for Clinical Chemistry and Laboratory Medicine (DGKL) addresses these issues on the basis of currently available data sets in this rapidly moving field.

Machine perfusion of circulatory determined death hearts: A scoping review

BACKGROUND

Ex vivo machine perfusion (EVMP) is reported to can successfully be applied for donor heart preservation. To respond to the organ shortage, some centres also accept hearts from marginal donors such as non-heart beating donors (NHBD) or hearts donated after cardiac death (DCD) for heart transplantation (HTx). Clinical as well as preclinical science on EVMP of DCD hearts seems to be promising but the ideal perfusion practice itself appears unclear.

OBJECTIVES

In accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA), this systematic review scopes all EVMP techniques for human and animal DCD heart preservation and addresses three specific questions, which refer to (a) the perfusion solutions, (b) the perfusion parameters and respective target values and (c) if possible, a direct comparison between cold static storage (CSS) and EVMP.

RESULTS

Search results predominantly consisted of animal studies. Either perfusion with a crystalloid or blood-based solution, each with cardioplegic or non-cardioplegic properties was used. Some perfusates were supplemented with specific pharmacological medication to block pathophysiological pathways, which are involved in ischemia/reperfusion injury or edema formation. Besides normothermic EVMP with oxygenated blood, a wide range of temperature was applied in all approaches, with the lowest temperature at 4 °C. Pressure controlled anterograde Langendorff perfusion was applied mostly. If investigated, crystalloid machine perfusion was presented superior to CSS.

CONCLUSIONS

Only blood based EVMP was introduced into clinical practice. More research, clinical as well as preclinical, is needed to develop the ideal EVMP technique, in terms of blood or crystalloid perfusion.

Many-Body Physics of Single and Double Spin-Flip Excitations in NiO

Understanding many-body physics of elementary excitations has advanced our control over material properties. Here, we study spin-flip excitations in NiO using Ni L_{3}-edge resonant inelastic x-ray scattering (RIXS) and present a strikingly different resonant energy behavior between single and double spin-flip excitations. Comparing our results with single-site full-multiplet ligand field theory calculations we find that the spectral weight of the double-magnon excitations originates primarily from the double spin-flip transition of the quadrupolar RIXS process within a single magnetic site. Quadrupolar spin-flip processes are among the least studied excitations, despite being important for multiferroic or spin-nematic materials due to their difficult detection. We identify intermediate state multiplets and intra-atomic core-valence exchange interactions as the key many-body factors determining the fate of such excitations. RIXS resonant energy dependence can act as a convincing proof of existence of nondipolar higher-ranked magnetic orders in systems for which, only theoretical predictions are available.

Topical use of amitriptyline and linoleic acid to restore ceramide rheostat in atopic dermatitis lesions - a case report

Rebuilding, stabilizing and maintaining the dermal lipid barrier is an encouraging disease management concept (relief and care) in the treatment and prevention of atopic dermatitis. Prevention and topical treatment, however, lack a simple, safe, effective and modular approach. For decades, the mainstay of topical therapy of atopic dermatitis has been corticosteroids, with innovations being rare. Our case report demonstrates the struggle of a patient with little relief of itchy dermal lesions and the recurrence of skin lesions following current therapeutic guidelines which proved to be ineffective. Therefore we decided to try an advanced C₁₆-ceramide pathomechanism derived topical therapeutic measure since it offers hope of re-establishing skin and alleviating suffering. Amitriptyline in combination with linoleic acid offers a chance to release from dry and itchy skin, mild to moderate atopic dermatitis lesions without known serious adverse effects of topical corticosteroids, while preventing recurrence.

Biomechanical evaluation of two methods of fixation of a flexor hallucis longus tendon graft

Aims

The traditional transosseus flexor hallucis longus (FHL) tendon transfer for patients with Achilles tendinopathy requires two incisions to harvest a long tendon graft. The use of a bio-tenodesis screw enables a short graft to be used and is less invasive, but lacks supporting evidence about its biomechanical behaviour. We aimed, in this study, to compare the strength of the traditional transosseus tendon-to-tendon fixation with tendon-to-bone fixation using a tenodesis screw, in cyclical loading and ultimate load testing.

Materials and Methods

Tendon grafts were undertaken in 24 paired lower-leg specimens and randomly assigned in two groups using fixation with a transosseus suture (suture group) or a tenodesis screw (screw group). The biomechanical behaviour was evaluated using cyclical and ultimate loading tests. The Student’s t-test was performed to assess statistically significant differences in bone mineral density (BMD), displacement, the slope of the load-displacement curves, and load to failure.

Results

The screw group showed less displacement (loosening) during cyclical loading, which was significant during 300, 500, 600, 700, 800, 900, and 1000 cycles (p < 0.05: other cycles: 0.079 < p < 0.402). Compared with the suture group, the screw group had higher mean ultimate load values (133.6 N, sd 73.5 vs 110.1 N, sd 46.2; p = 0.416).

Conclusion

Fixation of the FHL tendon with a tenodesis screw enables a less invasive procedure to be undertaken and shows similar biomechanical behaviour and primary strength compared with fixation using a transosseus suture. Cite this article: Bone Joint J 2018;100-B:1175–81.

Motion artifacts in standard clinical setting obscure disease-specific differences in quantitative susceptibility mapping

As quantitative susceptibility mapping (QSM) is maturing, more clinical applications are being explored. With this comes the question whether QSM is sufficiently robust and reproducible to be directly used in a clinical setting where patients are possibly not cooperative and/or unable to suppress involuntary movements sufficiently. Twenty-nine patients with Alzheimer's disease, 31 patients with mild cognitive impairment and 41 healthy controls were scanned on a 3 T scanner, including a multi-echo gradient-echo sequence for QSM and an inversion-prepared segmented gradient-echo sequence (T1-TFE, MPRAGE). The severity of motion artifacts (excessive/strong/noticeable/invisible) was categorized via visual inspection by two independent raters. Quantitative susceptibility was reconstructed using 'joint background-field removal and segmentation-enhanced dipole inversion', based on segmented subcortical gray-matter regions, as well as using 'morphology enabled dipole inversion'. Statistical analysis of the susceptibility maps was performed per region. A large fraction of the data showed motion artifacts, visible in both magnitude images and susceptibility maps. No statistically significant susceptibility differences were found between groups including motion-affected data. Considering only subjects without visible motion, significant susceptibility differences were observed in caudate nucleus as well as in putamen. Motion-effects can obscure statistically significant differences in QSM between patients and controls. Additional measures to restrict and/or compensate for subject motion should be taken for QSM in standard clinical settings to avoid risk of false findings.

Cardiac frequency and cutaneous microcirculation during and after exercising in the view of physical condition

INTRODUCTION

In the field of cardiovascular diseases an ergometer test is a common diagnostical method in which a change in microcirculation can be reached. In this paper cardiac frequency and cutaneous microcirculation during and after exercising will be compared with each other.

MATERIALS AND METHODS

The cutaneous microcirculation of  6 healthy volunteers (2 females, 4 males) is measured. As an instrument the PeriFlux 5000 combined with a Laser-Doppler-Flow(LDF)-Probe (Perimed Instruments) is used. The cardiac frequency (CF) is measured by the POLAR T31 sensor and as an ergometer the ERGO-FIT ® 457 is used.

RESULTS

The mean initial LDF (97,7±57,3 PU) decreases at the beginning (64,5±21,7 PU), increases during theexercise, reaches its maximum (247,8±82,1 PU) after the end of the exercise and drops to lower values (256,4±69,5 PU)after a few minutes. Contrasting to the LDF the mean initial CF (86±22/min) increases at the beginning (97±9/min),furthermore during the whole exercise (103±9/min) and then falls after having finished the exercise (96±3/min).Furthermore, during regeneration, one can see the CF decreasing towards its initial value, while LDF reaches its maximum.

CONCLUSION

In further studies, realized with volunteers with well-known levels of physical condition, a directconnection between cutaneous microcirculation and physical condition might be found.

Using the mean platelet volume MPV for the quality assessment of apheresis procedures

INTRODUCTION

Referring to current standards the quality of an apheresis procedure is estimated by the quantity of collected cells. Nowadays a new kind of quality measurement could be found in the detection of cell volumina. Recent diagnostics have shown that stem cells and platelets - when separated - are likely to appear in a higher volume inside the cell product. Therefore, in this study the question should be discussed wether platelets of higher volume are more likely to be separated than platelets showing a lesser volume.

METHODS

Blood samples of three different apheresis procedures could be observed: allogenic platelet donations (n = 7) (Trima, Terumo), autologous (n = 5) and allogenic stem cell donations (n = 5) (Cobe Spectra, Terumo). To examine the blood samples the Sysmex hematology analyser (XT-2000) has been used.

RESULTS

During stem cell apheresis, the volume of the separated platelets was 1.2 fold increased compared to the platelet volume in the peripheral blood before separation. Before apheresis the mean platelet volume in the peripheral blood was found to be 6,21 fl, after apheresis 6,09 fl and inside the platelet concentrate 7,42 fl. The platelet number in the peripheral blood was also significantly decreased (before separation 180.1/nl and after separation 133.5/nl). In the blood products the concentration of platelets was nearly 8 fold higher than in the peripheral blood before separation.

CONCLUSION

Overall, the observed apheresis procedures are more likely to separate platelets showing a higher voulme than common in the peripheral blood. This might indicate that not only the amount of separated cells reflects the quality of the apheresis procedure but also that the volume of the separated cells can be used as a parameter for quality assessment.

Influence of Di(2-ethylhexyl)phthalate on migration rate and differentiation of human hematopoietic stem and progenitor cells (CD34+)

INTRODUCTION

Phthalates are a group of synthetic plasticizers that are ubiquitous environmental pollutants with toxic and endocrine disrupting characteristics. DEHP is the most commonly used plasticizer in the world and is still applied to stem cell transfusion bags used for storage of hematopoietic stem and progenitor cells (CD34+ HSPC), which are transferred during stem cell transplantation. Here we examined the effect of DEHP on vitality of CD34+ HSPC as well as stem cell specific properties like migration and differentiation capacity - both important for successful stem cell transplantations.

MATERIAL AND METHODS

CD34+ HSPC were incubated for 24 h and 72 h with DEHP concentrations ranging from 1 μg/ml to 250 μg/ml. DEHP was diluted in DMSO. Migration rate was analyzed along an SDF-1α gradient using Transwell migration inserts. Differentiation of CD34+ HSPC was investigated after two weeks in methylcellulose with colony stimulating factors. Apoptosis rate was measured via Annexin V and 7-AAD staining.

RESULTS

24 h of incubation with 10 μg/ml DEHP led to a significant (p <  0.01) decrease in migration rate of CD34+ HSPC (70.70% ± 7.53% ) with a minimum migration rate of 48.33% ± 6.72% in relation to control after incubation with 100 μg/ml DEHP for 72 h. Incubation with the highest tested DEHP concentrations (50 and 100 μg/ml) significantly (p <  0.05) altered colony formation rate and cell type distribution. Apoptosis rate of CD34+ HSPC significantly (p <  0.05) increased after incubation with concentrations of 10 μg/ml DEHP for 24 h (1.46 ± 0.19) with a maximum apoptosis rate of 2.71 ± 0.66 after 24 h incubation with the highest DEHP concentration (250 μg/ml) in relation to control.

CONCLUSIONS

As shown, DEHP takes impact on migration rate, apoptosis rate, and differentiation of CD34+ HSPC. As these are functions with an important role in stem cell transplantations, the usage of DEHP-free stem cell transfusion bags should be considered.

Impact of Di(2-ethylhexyl)phthalate on migration rate of human promyelocytic leukemia cells (HL-60)

INTRODUCTION

Softeners like phthalate esters are ubiquitous in the environment and have been detected in transfusion bags, though there is only a limited amount of studies on the effect of phthalates on blood cells. This study seeks to determine effects on cell migration of human promyelocytic leukemia cells (HL-60) incubated with di(2-ethylhexyl)phthalate (DEHP) at concentrations found in blood bags.

MATERIAL AND METHODS

HL-60 cells were incubated with DEHP concentrations ranging from 0.1 μg/ml to 1000 μg/ml, diluted in DMSO, over 24 h, 48 h, and 72 h. Migration rate was analyzed along an SDF-1α gradient using Transwell migration inserts.

RESULTS

Of the applied concentrations 100 μg/ml, 250 μg/ml, 500 μg/ml, and 1000 μg/ml showed a significant decrease in migration rates relative to DMSO control at all measuring points (p < 0.05), with relative migration rates between 37.87 % for 100 μg/ml and 25.34 % for 1000 μg/ml relative to DMSO after 24 h of stimulation and 19.73 % for 100 μg/ml and 14.69 % for 1000 μg/ml respectively after 72 h of incubation.

CONCLUSION

Our results indicate HL-60 to be a suitable in vitro model for examining effects of DEHP on the migration of blood and nucleated cells at concentrations found in blood bags.

Radiographic contrast media alterate the localization of actin/band4.9 in the membrane cytoskeleton of human erythrocytes

Different radiographic contrast media (RCM) were shown to induce morphological changes of blood cells (e.g. erythrocytes or thrombocytes) and endothelial cells. The echinocytic shape change of erythrocytes, particularly, affords alterations of the membrane cytoskeleton. The cytoskeleton plays a crucial role for the shape and deformability of the red blood cell. Disruption of the interaction between components of the red blood cell membrane cytoskeleton may cause a loss of structural and functional integrity of the membrane. In this study band4.9 and actin as components of the cytoskeletal junctional complex were examined in human erythrocytes after suspension in autologous plasma or in plasma RCM mixtures (30% v/v Iodixanol-320 or Iopromide-370) followed by a successive double staining with TRITC-/FITC-coupled monoclonal antibodies. After adding Iopromide-370 to the plasma in practically none of the cells the rounded conformation of the membrane cytoskeleton - as it appeared in cells suspended in autologous plasma - was found. In addition, Iopromide-370 induced thin lines and coarse knob-like structures of band4.9 at the cell periphery while most cell centers were devoid of band4.9, and a box-like arrangement of bands of band4.9. A dissociation between colours red (actin) and green (band4.9) occurred as well. In contrast, erythrocytes suspended in a plasma/Iodixanol-320 mixture showed a membrane cytoskeleton comparable to cells suspended in autologous plasma, Similar results were found with respect to the distribution of actin. This study revealed for the first time RCM-dependent differences in band4.9 activities as possible pathophysiological mechanism for the chemotoxicity of radiographic contrast media.

Effects of radiographic contrast media on the micromorphology of the junctional complex of erythrocytes visualized by immunocytology

Effects of radiographic contrast media (RCM) application were demonstrated in vitro and in vivo where the injection of RCM into the A. axillaris of patients with coronary artery disease was followed by a significant and RCM-dependent decrease of erythrocyte velocity in downstream skin capillaries. Another study in pigs revealed that the deceleration of erythrocytes coincided with a significant reduction of the oxygen partial pressure in the myocardium--supplied by the left coronary artery--after the administration of RCM into this artery. Further reports showed RCM dependent alterations of erythrocytes like echinocyte formation and exocytosis, sequestration of actin or band 3 and the buckling of endothelial cells coinciding with a formation of interendothelial fenestrations leading to areas devoid of endothelial cells. Key to morphological alterations of erythrocytes is the membrane cytoskeleton, which is linked to the band 3 in the erythrocyte membrane via the junctional complex. Fundamental observations regarding the cell biological and biochemical aspects of the structure and function of the cell membrane and the membrane cytoskeleton of erythrocytes have been reported. This review focuses on recent results gained, e.g., by advanced confocal laser scanning microscopy of different double-stained structural elements of the erythrocyte membrane cytoskeleton.

Effect of radiographic contrast media on the spectrin/band3-network of the membrane skeleton of erythrocytes

The membrane of red blood cells consists of a phospholipid bilayer with embedded membrane proteins and is associated on the cytoplasmatic side with a network of proteins, the membrane skeleton. Band3 has an important role as centre of the functional complexes e.g. gas exchange complex and as element of attachment for the membrane skeleton maintaining membrane stability and flexibility. Up to now it is unclear if band3 is involved in the morphology change of red blood cells after contact with radiographic contrast media. The study revealed for the first time that Iopromide induced markedly more severe alterations of the membrane skeleton compared to Iodixanol whose effects were similar to erythrocytes suspended in autologous plasma. A remarkable clustering of band3 was found associated with an accumulation of band3 in spicules and also a sequestration of band3 to the extracellular space. This was evidently accompanied by a gross reduction of functional band3 complexes combined with a dissociation of spectrin from band3 leading to a loss of homogeneity of the spectrin network. It could be demonstrated for the first time that RCM not only induced echinocyte formation but also exocytosis of particles at least coated with band3.

Effects of gamma irradiation and 15 days of subsequent ex vivo storage on the cytosolic red blood cell proteome analyzed by 2D-DIGE and Orbitrap MS

PURPOSE

Gamma irradiation of red blood cell (RBC) concentrates is routinely used to prevent transfusion-associated graft-versus-host disease. So far, the effects of ionizing radiation on RBC structure and function and especially the proteome are not fully understood.

EXPERIMENTAL DESIGN

RBC concentrates were irradiated with 30 Gy and stored for 1 or 15 days at 4 ± 2°C. Following cell lysis and hemoglobin depletion, 2D-DIGE was used to examine the changes of the cytosolic RBC proteome. Significantly altered spots were analyzed using bottom-up proteomic approaches and selected marker proteins validated by western blotting.

RESULTS

Gamma irradiation was found to enhance conventional RBC storage lesions. Following 15 days of postirradiation storage, the abundances of a total of 27 spots were significantly altered and 3 out of 13 identified proteins were selected and validated as potential marker proteins for the assessment of irradiation-induced cytosolic RBC lesions.

CONCLUSIONS AND CLINICAL RELEVANCE

Gamma irradiation and subsequent ex vivo storage according to the Council of Europe guidelines were found to affect RBC protein structures. The validated marker proteins can serve as a basis for the development of a screening assay to monitor the quality of irradiated RBC concentrates during ex vivo storage.

Novel effects of adenosine receptors on pericellular hyaluronan matrix: implications for human smooth muscle cell phenotype and interactions with monocytes during atherosclerosis

Hyaluronan (HA) is responsive to pro-atherosclerotic growth factors and cytokines and is thought to contribute to neointimal hyperplasia and atherosclerosis. However, the specific function of the pericellular HA matrix is likely depend on the respective stimuli. Adenosine plays an important role in the phenotypic regulation of vascular smooth muscle cells (VSMC) and is thought to inhibit inflammatory responses during atherosclerosis. The aim of this study was to examine the regulation and function of HA matrix in response to adenosine in human coronary artery SMC (HCASMC). The adenosine receptor agonist NECA (10 μM) caused a strong induction of HA synthase (HAS)1 at 6 h and a weaker induction again after 24 h. Use of selective adenosine receptor antagonists revealed that adenosine A2(B) receptors (A2(B)R) mediate the early HAS1 induction, whereas late HAS1 induction was mediated via A2(A)R and A3R. The strong response after 6 h was mediated in part via phosphoinositide-3 kinase- and mitogen-activated protein kinase pathways and was inhibited by Epac. Functionally, NECA increased cell migration, which was abolished by shRNA-mediated knock down of HAS1. In addition to HA secretion, NECA also stimulated the formation of pronounced pericellular HA matrix in HCASMC and increased the adhesion of monocytes. The adenosine-induced monocyte adhesion was sensitive to hyaluronidase. In conclusion, the current data suggest that adenosine via adenosine A2(B)R and A2(A)R/A3R induces HAS1. In turn a HA-rich matrix is formed by HCASMC which likely supports the migratory HCASMC phenotype and traps monocytes/macrophages in the interstitial matrix.

Monitoring drug residues in donor blood/plasma samples using LC-(MS)/MS--a pilot study

Quality assurance of pharmaceutical products is of particular importance and thoroughly controlled. Among these, the preparation of human plasma follows strict guidelines from the point of donor selection to product processing. While various precautions particularly concerning antiviral treatment as well as quality assessment are standard procedure, tests for drug residues are rarely, if at all, conducted with fresh frozen plasma products. With the constantly increasing sensitivity and specificity of modern analytical instruments, the detection of trace amounts of therapeutics in plasma is feasible and can be applied to blood products where considered appropriate. To estimate the prevalence of a selection of commonly prescribed and over-the-counter drugs (including diuretics, beta-receptor blocking agents, contraceptives, β2 -agonists, antibiotics, antidepressants, analgesics, opioids, glucocorticosteroids, benzodiazepines, stimulants, and oral anti-diabetics) as well as cannabinoids in human donor plasma, a total of 100 specimens (61 female, 39 male) collected at the German Red Cross Organization in 2012 was subjected to an established analytical approach. The methodology was based on protein precipitation followed by liquid chromatographic-high resolution/high accuracy mass spectrometric analysis. Following initial test results, confirmatory analyses were conducted with respective reference substances employing a conventional liquid chromatography-triple-quadrupole mass spectrometer (LC-MS/MS) apparatus. Out of one hundred samples, five were found to contain diuretics (four hydrochlorothiazide and one torasemide), five contained beta-receptor blocking agents (four bisoprolol and one metoprolol), one was found with residues of pseudoephedrine (stimulant) and one with drosperinone (contraceptive). Overall, 12% of samples yielded detectable amounts of drug residues at concentrations estimated to levels common to individuals under therapeutic treatment. In addition, six aliquots of different lots of commercially available plasma preparations with solvent-detergent processing were tested. Here, no drug residues of the targeted therapeutics were detected.