Hazard assessment of complex legacy-contaminated groundwater mixtures using a novel approach method in adult fathead minnows

Traditional risk assessment methods face challenges in the determination of drivers of toxicity for complex mixtures such as those present at legacy-contaminated sites. Bioassay-driven analysis across several levels of biological organization represents an approach to address these obstacles. This study aimed to apply a novel transcriptomics tool, the EcoToxChip, to characterize the effects of complex mixtures of contaminants in adult fathead minnows (FHMs) and to compare molecular response patterns to higher-level biological responses. Adult FHMs were exposed for 4 and 21 days to groundwater mixtures collected from a legacy-contaminated site. Adult FHM showed significant induction of micronuclei in erythrocytes, decrease in reproductive capacities, and some abnormal appearance of liver histology. Parallel EcoToxChip analyses showed a high proportion of upregulated genes and a few downregulated genes characteristic of compensatory responses. The three most enriched pathways included thyroid endocrine processes, transcription and translation cellular processes, and xenobiotics and reactive oxygen species metabolism. Several of the most differentially regulated genes involved in these biological pathways could be linked to the apical outcomes observed in FHMs. We concluded that molecular responses as determined by EcoToxChip analysis show promise for informing of apical outcomes and could support risk assessments of complex contaminated sites.

Characterization of molecular and apical effects of legacy-contaminated groundwater on early life stages of fathead minnows

Mechanistic toxicology approaches represent a promising alternative to traditional live animal testing; however, the often-noted uncertainties concerning the linkages between effects observed at molecular and apical levels curtails the adoption of such approaches. The objective of this study was to apply a novel transcriptomics tool, EcoToxChips, to characterize the effects of complex mixtures of contaminants in fish and to compare molecular response patterns to higher-level biological responses including swimming behavior, deformities, and mortality. Fathead minnow (FHM) embryos were exposed for seven days to increasing concentrations of groundwater collected from moderate (MIAZ) and high (HIAZ) industrial activity zones of a legacy contaminated site. There was a concentration-dependent disruption of photo-dependent swimming responses associated with avoidance behavior patterns and spinal deformities (HIAZ and MIAZ), and an induction of pericardial edema and mortality (HIAZ-10%). Parallel EcoToxChip analyses showed a shift from a majority of upregulated genes at lower concentrations to a majority of downregulated genes at higher concentrations for both treatment conditions. Many of the significantly differentially regulated genes were involved in biological pathways including induction of oxidative stress, activating of several metabolic processes and growth, cell death, and inhibition of signal transduction signaling processes. Several contaminants present in the groundwater mixtures could have contributed to an exceedance of antioxidant system capacities that possibly led to the deformities, altered swimming behaviours, and mortality observed in FHMs. Therefore, molecular response patterns could be linked to apical outcomes observed in this study. Overall, the results observed in this study demonstrate that transcriptomics approaches such as the EcoToxChip system could be supportive of risk assessment of complex contaminated sites.

Apical and mechanistic effects of 6PPD-quinone on different life-stages of the fathead minnow (Pimephales promelas)

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-quinone) is an emerging contaminant of concern that is generated through the environmental oxidation of the rubber tire anti-degradant 6PPD. Since the initial report of 6PPD-quinone being the cause of urban runoff mortality syndrome of Coho salmon, numerous species have been identified as either sensitive or insensitive to acute lethality caused by 6PPD-quinone. In sensitive species, acute lethality might be caused by uncoupling of mitochondrial respiration in gills. However, little is known about effects of 6PPD-quinone on insensitive species. Here we demonstrate that embryos of fathead minnows (Pimephales promelas) are insensitive to exposure to concentrations as great as 39.97 μg/L for 168 h, and adult fathead minnows are insensitive to exposure to concentrations as great as 9.4 μg/L for 96 h. A multi-omics approach using a targeted transcriptomics array, (EcoToxChips), and proton nuclear magnetic resonance (1H NMR) was used to assess responses of the transcriptomes and metabolomes of gills and livers from adult fathead minnows exposed to 6PPD-quinone for 96 h to begin to identify sublethal effects of 6PPD-quinone. There was little agreement between results of the EcoToxChip and metabolomics analyses, likely because genes present on the EcoToxChip were not representative of pathways suggested to be perturbed by metabolomic analysis. Changes in abundances of transcripts and metabolites in livers and gills suggest that disruption of one‑carbon metabolism and induction of oxidative stress might be occurring in gills and livers, but that tissues differ in their sensitivity or responsiveness to 6PPD-quinone. Overall, several pathways impacted by 6PPD-quinone were identified as candidates for future studies of potential sublethal effects of this chemical.

Bleeding Complications in Patients With Severe Frostbite Injury

Frostbite is caused by exposure to cold temperatures and can lead to severe injury resulting in amputations. Tissue plasminogen activator (tPA) is a thrombolytic agent that has demonstrated efficacy preventing amputation in frostbite patients. The goal of frostbite management with tPA is to salvage tissue without causing clinically significant bleeding complication. The purpose of this study was to characterize bleeding complications in severe frostbite patients managed with and without tPA. Retrospective chart review of severe frostbite patients admitted to a single ABA verified burn center. Bleeding events were grouped: category 0: no bleed; category 1: bleed not resulting in change or intervention; category 2: bleed resulting in change of management; and category 3: bleed resulting in change of management and intervention. Over a 7-year period, 188 patients were included in the study. Most patients had no documentation suggesting a bleeding complication: 69.7% category 0, 19.1% category 1, 4.8% category 2, and 6.4% category 3. There was no significant difference in category 2 or 3 bleeding complications between patients treated with or without tPA. Overall, 9 of the 143 patients (6.3%) treated with tPA had a category 2 or 3 bleeding complication within 12 hours of tPA completion and 12 of 143 (8.4%) within 24 hours of tPA completion. Based on the low risk of severe bleeding and significant benefit relative to limb or digit salvage demonstrated in this study, we conclude that tPA is safe and effective for the treatment of frostbite in appropriately selected patients.

Abdominal ultrasound in head and neck squamous cell carcinoma staging: yes or no?

PURPOSE

Abdominal ultrasound is a diagnostic staging procedure for distant metastases in head and neck squamous cell carcinoma (HNSCC). However, currently performed abdominal staging procedures do not follow consistent standards. Therefore, this retrospective study on 498 patients aimed at investigating on abdominal ultrasound as a staging procedure in HNSCC.

MATERIALS AND METHODS

A retrospective analysis of 498 head and neck cancer patients treated in our Department of Head and Neck Surgery between 2008 and 2015 was performed. Disease-related data were collected over a mean follow-up time of 30.3 months, and results of abdominal ultrasound were analyzed.

RESULTS

426 patients received abdominal ultrasound as a staging procedure. 7% (29) were suspicious for metastases. In 19 cases (66%), the detected abnormalities were masses of the liver. In four patients, abdominal metastases were confirmed at the time of initial diagnosis. 16 patients developed abdominal metastases in the course of the disease (on average 623 days after initial diagnosis). 19 out of 20 patients with abdominal metastases had an N2/N3 cervical lymph node status. In this study, the negative predictive value of abdominal ultrasound for HNSCC staging was 99.03%, while the positive predictive value yielded 5.88% (N2/N3-patients).

CONCLUSION

Only in patients with locally advanced lymph-node-status (N2/N3), abdominal ultrasound can be useful as a staging investigation to exclude abdominal metastasis in HNSCC patients. For N0/N1 patients, abdominal ultrasound might be dispensed. Of note, in case of a positive result, further diagnostic procedures are mandatory.

Target Organ Toxicity in Rats After Subchronic Oral Exposure to Soil Extracts Containing a Complex Mixture of Contaminants

Complex mixtures of unknown contaminants present a challenge to identify toxicological risks without using large numbers of animals and labor-intensive screens of all organs. This study examined soil extracts from a legacy-contaminated pesticide packaging and blending site. HepG2 cytotoxicity was used as an initial screen of 18 soil samples; then, three extracts (A, B and C) from different locations at the study site were used for testing in animals. The first two extracts were identified as the most toxic in vitro, and the latter extract obtained from a location further from these two toxic sampling sites. Then, target organ toxicities were identified following biweekly oral gavage for one month of three soil extracts (0.1% in polyethylene glycol or PEG) compared to vehicle control in male Sprague-Dawley rats (n = 9-10/group). Exposure to extract A significantly increased neutrophils and lymphocytes compared to control. In contrast, all extracts increased plasma α-2 macroglobulin and caused mild-to-moderate lymphocytic proliferation within the spleen white pulp, all indicative of inflammation. Rats exposed to all soil extracts exhibited acute tubular necrosis. Cholinesterase activity was significantly reduced in plasma, but not brain, after exposure to extract A compared to control. Increased hepatic ethoxyresorufin-o-deethylase activity compared to control was observed following exposure to extracts A and B. Exposure to soil extract C in rats showed a prolonged QTc interval in electrocardiography as well as increased brain lipid peroxidation. Candidate contaminants are organochlorine, organophosphate/carbamate pesticides or metabolites. Overall, HepG2 cytotoxicity did not successfully predict the neurotoxicity and cardiotoxicity observed with extract C but was more successful with suspected hydrocarbon toxicities in extracts A and B. Caution should be taken when extrapolating the observation of no effects from in vitro cell culture to in vivo toxicity, and better cell culture lines or assays should be explored.

Impact of myocardial injury on regional left ventricular function in the course of acute myocarditis with preserved ejection fraction: insights from segmental feature tracking strain analysis using cine cardiac MRI

The aim of this study was to provide insights into myocardial adaptation over time in myocyte injury caused by acute myocarditis with preserved ejection fraction. The effect of myocardial injury, as defined by the presence of late gadolinium enhancement (LGE), on the change of left ventricular (LV) segmental strain parameters was evaluated in a longitudinal analysis. Patients with a first episode of acute myocarditis were enrolled retrospectively. Peak radial (PRS), longitudinal (PLS) and circumferential (PCS) LV segmental strain values at baseline and at follow-up were computed using feature tracking cine cardiac magnetic resonance imaging. The change of segmental strain values in LGE positive (LGE+) and LGE negative (LGE-) segments was compared over a course of 89 ± 20 days. In 24 patients, 100 LGE+ segments and 284 LGE- segments were analysed. Between LGE+ and LGE- segments, significant differences were found for the change of segmental PCS (p < 0.001) and segmental PRS (p = 0.006). LGE + segments showed an increase in contractility, indicating recovery, and LGE- segments showed a decrease in contractility, indicating normalisation after a hypercontractile state or impairment of an initially normal contracting segment. No significant difference between LGE+ and LGE- segments was found for the change in segmental PLS. In the course of acute myocarditis with preserved ejection fraction, regional myocardial function adapts inversely in segments with and without LGE. As these effects seem to counterbalance each other, global functional parameters might be of limited use in monitoring functional recovery of these patients.

Dapagliflozin alleviates left ventricular hypertrophy and cardiac dysfunction in mice

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Ludwig Boltzmann Institute for Cardiovascular Research

Introduction

Sodium glucose cotransporter 2 inhibitors (SGLT2i) are a class of oral antidiabetic drugs. Recent clinical trials demonstrated and proved the cardiovascular benefit of SGLT2i in patients suffering from ischemic heart disease. In addition, left ventricular hypertrophy (LVH) is associated with cardiovascular events and using SGLT2i alleviated LVH in diabetic patients. However, only few studies investigated the effect of SGLT2i on regression of LVH in absence of diabetes.

Aim of the study

This study aimed to investigate whether the SGLT2i Dapagliflozin (DAPA) could attenuate LVH and cardiac dysfunction in a mouse model of pressure overload-induced LVH.

Methods

Male C57BL/6J mice (body weight 20-25g) were used. LVH was induced surgically by transverse aortic constriction (TAC). DAPA (1 mg/kg bodyweight/day) was administered through drinking water. The animals were divided in four groups: Group 1 underwent TAC for eight weeks (n=8). Group 2 concomitantly received DAPA for eight weeks after TAC (n=5). Group 3 received DAPA for only two weeks (in week 7 and 8 after TAC, n=5) to clarify if DAPA treatment could alleviate LVH at a later timepoint. Group 4 served as a sham control group (no LVH, n=8). Cardiac function was assessed using transthoracic echocardiography and invasive LV hemodynamic measurements.

Results

TAC resulted in a significant reduction in LV ejection fraction (LVEF) and significant increase in heart weight to body weight ratio (HW/BW) compared to sham (p&lt;0.001). In addition, TAC mice showed a significant increase of LV systolic pressure and end-diastolic pressure compared to sham (p&lt;0.01). Both the LVEF and LV functional parameters were markedly improved in mice treated with DAPA for eight weeks (p&lt;0.05). LV mass decreased compared to the untreated group. More importantly, DAPA treatment for only two weeks also improved LVEF and alleviated LVH compared to untreated TAC mice (p&lt;0.05). Furthermore, we also found that mice with only two weeks of DAPA treatment showed a tendency to improve LV hemodynamics.

Conclusions

DAPA was cardioprotective in a mouse model of pressure overload-induced LVH in absence of diabetes. It improved LV contractile function and LVH. DAPA also alleviated LVH and induced LV regression. Our findings uncovered that the SGLT2i DAPA contributed to the regression of LVH and cardiac fibrosis. Thus, administration of SLGT2i may be a novel adjunct therapy to boost reverse remodeling e.g. in patients with elective cardiac surgery and hypertrophic cardiomyopathy.

St Thomas Hospital polarizing cold cardioplegia does not have superior effects on hemodynamic parameters in an infarcted rat model

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Orphan Drugs

Background

The use of cardioplegic solutions is indispensable during cardiac arrest in order to reduce myocardial metabolism and oxygen demand. Most commonly, hypothermic hyperkalemic cardioplegic solutions are used for open heart surgery. However, high potassium concentrations have several effects that limit left ventricular recovery, such as intracellular calcium overload resulting in the loss of contractility and increased cell death. Recently, we have shown that polarized cardiac arrest results in similar myocardial protection and improves cardiac functional recovery in a porcine model of cardiopulmonary bypass.

Purpose

The purpose of this study was to identify and compare the hemodynamic effects of cold St Thomas’ Hospital polarizing cardioplegia (STH-Pol) in contrast to standard St Thomas’ Hospital cardioplegia (STH2) in rats with chronic myocardial infarction. We hypothesize that St Thomas’ Hospital polarizing cardioplegia shows superior protection on left ventricular hemodynamic recovery as compared to standard STH2 cardioplegia.

Methods

Permanent myocardial infarction was induced by permanent occlusion of the left anterior descending artery LAD on Sprague-Dawley rats (593 ± 65g, day of sacrifice). Six weeks post-MI, after echocardiography assessment, the animals were sacrificed, and hemodynamic parameters were measured in an erythrocyte-perfused isolated heart model (STH2, control group: n=5 or STH-Pol, study group: n=4). Fifteen minutes of Langendorff mode and 30 minutes of Working-heart mode were followed by cardiac arrest with the two types cardioplegia (was applied three times every 20 minutes (t1= 0, t2= 20, t3= 40)). STH-Pol, consisting of esmolol, adenosine and magnesium, was mixed with erythrocyte-buffer shortly prior to administration (1:4). After ischemia, the hearts were started with a hot shot with warm erythrocyte-buffer. Hemodynamic parameters were measured every five minutes in Langendorff mode and Working-heart mode. Finally, pump function was examined and tissue samples were taken for analysis of troponin-T and high-energy phosphates. Results will be given as % of preischemic baseline value.

Results

The use of STH-Pol instead of STH2 did not yield any significant differences in hemodynamic recovery (%) across the parameters of left atrial flow (LAF: 40.87 ± 13.22 vs. 53.24 ± 11.27), coronary flow (CF: 58 ± 14.36 vs. 76.21 ± 9) and cardiac output (CO: 42.82 ± 13.36 vs. 51.83 ± 11.76). Furthermore, we have not been able to identify superior effects of STH-Pol on stroke volume (SV: 46.55 ± 13.91 vs. 52.66 ± 11.33) recovery. Moreover, heart rate was comparable in both groups (92.07 ± 2.02 vs. 99.35 ± 1.72), which indicates swift reversal of negative chronotropic effects of esmolol.

Conclusion

Polarizing cardioplegic arrest does not show superior effects on hemodynamic parameters of left ventricular recovery after ischemia in chronically infarcted rat hearts as compared to depolarizing cardioplegic arrest.

Stromal Vascular Fraction-based patches generated under perfusion culture enhance cardiac function in rats with chronic myocardial infarction

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Swiss National Foundation

The development of novel adjuvant angiogenic therapies to restore the low-perfused microvascular network upon myocardial infarction (MI) is crucial to avoid a possible end-stage heart failure. Of the current adult cell-based therapies, human adipose tissue-derived stromal vascular fraction cell (SVF) has vast reparative potential, principally due to: 1) its heterogeneous composition rich in mesenchymal stem cells (MSC), endothelial cells (EC), pericytes and hematopoietic cells, among others. In vitro engineering of SVF-based patches under unidirectional flow, applied by the help of a perfusion-based bioreactor, was found to increase certain cellular SVF subgroups such as pericytes, compared to static culture. In this study, we aimed at studying the potential of SVF-based engineered tissues in a model of chronic MI in nude rats. Human SVF cells were isolated upon liposuction and cultured on 3D collagen sponges (8 mm diameter, 3 mm thickness) either under constant unidirectional perfusion or in static condition for 5 days. Patches were characterized in terms of cellular composition prior to implantation. MI was induced by permanent ligation of the left anterior descending (LAD) coronary artery in male nude rats. Cardiac MRI was performed 4 weeks after MI; prior to the suture of patches and before sacrifice (4 weeks after implantation). Left ventricular ejection fraction (EF) was the surrogate marker and primary end point for cardiac pump function. Controls included untreated MI animals. Following perfusion culture, SVF cells were composed with a statistically superior percentage of pericytes, identified as CD45- CD34- CD146+ compared to static culture (28.06±10.03 and 3.37±2.50, respectively, p&lt;0.0007). The presence of other cell subpopulations was similar in the patches generated in perfusion or static culture. While the percentage of EF at the time of sacrifice resulted to be not statistically different between static and perfusion-based patches, statically generated constructs showed a general trend of decrease in the % EF before and after treatment (rat 1: 61.96 vs 52.90; rat 2: 55.39 vs 53.00; rat 3: 52.34 vs 50.62, respectively). Perfusion-cultured patches, instead, rather improved the cardiac function, measured as % EF (rat 1: 51.82 vs 58.72; rat 2: 51.66 vs 60.45; rat 3: 53.50 vs 52. 36, respectively for 4 weeks following MI and 4 weeks following treatment). When comparing the ratio of the % EF 8 weeks and 4 weeks between static or perfusion-based patches and the untreated controls, rats treated with patches generated under perfusion resulted to show higher levels of % EF, with an almost statistically difference (p=0.0556), compared to the control group. The observed results showed the great potential of human SVF-based patches in the improvement of the heart pump function.

Hypersensibilité au vaccin anti-COVID ? analyses de 1000 avis allergologiques

Introduction (contexte de la recherche)

Les services d’allergologie ont été fortement sollicités en raison de l’appréhension vis-à-vis du risque allergique des vaccins contre la COVID-19.

Objectif

Nous rapportons les 1000 premières prises en charge proposées et le résultat des investigations allergologiques réalisées.

Méthodes

Nous avons mis en place un système d’avis-COVID par mail à l’aide d’un questionnaire. Ceci nous a permis de colliger, de façon rétrospective les données démographiques des patients, les conduites à tenir proposées, en fonction des données cliniques fournies et des recommandations de la SFA. Pour certains, des tests cutanés ont été nécessaires : prick-test aux PEGs 3500/1500 et polysorbate 80 avec des concentrations maximales respectives de 100 mg/mL et 1000 mg/mL. Lorsque des fonds de flacon de vaccin étaient disponibles, nous avons réalisé : prick-test et IDR jusqu’à leur concentration pure. Certaines vaccinations jugées à risque ont été réalisées dans le service.

Résultats

Du 20 janvier au 24 novembre 2021, 1000 avis allergologiques ont été donnés par mail en dehors des heures de consultation. Il s’agissait de 773 avis pré-vaccinaux et 227 post-vaccinaux. L’âge moyen des patients était de 55 ans, avec une majorité de femmes. Nous avons levé la contre-indication allergologique à la vaccination dans 99,4 % des cas. Elle a été recommandée en centre de vaccination conventionnel pour 44 % sans précaution particulière, 31 % sous antihistaminique, 30 % avec 30 minutes de surveillance. 31 patients ont été vaccinés dans notre service sans réaction. L’indication de tests cutanés a été retenue dans 6,9 % des cas. Nous avons mis en évidence une sensibilisation aux excipients et aux vaccins chez 4 patients du groupe pré-vaccinal et chez une patiente du groupe post-vaccinal qui a bénéficié d’une désensibilisation avec succès.

Conclusions

La gestion par mail des avis-COVID a permis de limiter les consultations dédiées en présentiel et de maintenir l’intégralité des activités du service. Nous avons proposé une réponse rapide avec traçabilité écrite, souvent exigée. Seuls 4 patients restent à ce jour contre-indiqués à la vaccination en raison d’une allergie aux PEGs.

721 Defining Bleeding Characteristics in Frostbite Patients Managed with tPA

Introduction

Frostbite is caused by exposure to cold temperatures and can be a severe injury leading to hospital admissions, surgeries, or amputations. Disease progression involves endothelial injury, thrombosis, and tissue necrosis; therefore, management of patients involves a process of rewarming and restoration of blood flow to the affected area. Tissue plasminogen activator (tPA) is a thrombolytic agent that has demonstrated efficacy at restoring tissue perfusion in patients with frostbite. The goal of frostbite management with tPA is to salvage tissue without causing clinically significant bleeding, a documented adverse effect of tPA administration. The purpose of this study was to characterize specific bleeding complications associated with tPA administration. The secondary objective was to compare the rate of bleeding complications in frostbite patients treated with intravenous (IV) tPA to frostbite patients that did not receive tPA.

Methods

This single center retrospective study included all adult patients with severe frostbite who presented between October 2013 and March 2020. tPA was given to patients per institutional protocol. To assess for bleeding events, patient charts were reviewed and any instance of bleeding was categorized based on severity. Bleeding was categorized as: 1) none, 2) mild: not clinically significant (bandage or moved IV site), 3) moderate: change of management (tPA stopped, enoxaparin held, or specialty consult), and 4) severe: included a change and intervention (transfusion, fasciotomy for compartment syndrome). Any change in management or any additional therapies used to control bleeding were documented, as well as the timing of bleeding in relation to tPA administration.

Results

Over a 7-year period 209 patients were analyzed and 202 patients were included. For patients with bleeding events requiring intervention, the mean time to bleed was 105.5 hours (range 4 to 576 hours). Of these, 4 (3 transfusions and 1 fasciotomy for compartment syndrome) were temporally associated with tPA administration (within 24 hours). Two of the 4 patients had minor to moderate traumatic injury prior to admission, the 3rd patient had incomplete work-up at referring center that initiated tPA prior to transport, and the 4th patient was in restraints. Of the patients who did not receive tPA, 3.39% had a severe bleeding event requiring intervention compared to 6.99% of patients treated with tPA (P=0.516).

Conclusions

Though there was a higher incidence of bleeding in tPA-treated patients, for the majority of patients studied, tPA was safe for the treatment of severe frostbite. Bleeding events occur in frostbite patients treated with or without tPA and warrant close follow-up for these infrequent complications.

Global health from home - results from a German student-led online lecture series during COVID-19

Background

The COVID-19 pandemic calls for a skilled health workforce, yet global health is largely missing in the medical curriculum in Germany. The interdisciplinary national student “Global Health Network” therefore initiated an online lecture series. “Global Health - perspectives, opportunities and challenges” included 14 lectures on a range of topics held by German and international academics from October 2020 to January 2021.

Methods

Evaluations were performed prior to, at midterm and after the series, including 5-point likert scales and open questions. Using quantitative and qualitative approaches, participants' motivation and learning outcomes of global health education were analysed.

Results

A total of 1393 students registered for the series. Individual lectures attracted on average 400 participants, mainly female medical students between 20-25 years, but also a variety of ages, genders and disciplines. Main reasons for participation included interest in COVID-19-related developments, learning about global health-specific topics, and professional development. More than 40% of participants reported to know little about global health before attending; after the lecture series, only 10% made this statement. In addition, 90% of participants perceived an increase of motivation to learn more about the topics, while about 40% gained motivation to become practically involved in the field. The lecture series was accredited in the curriculum at some universities, thus innovating the curriculum and enabling formal credits.

Conclusions

The new model of student-led online teaching proved to be feasible and demonstrated students' interest and positive impact on global health knowledge. Further institutional change and inclusion of global health in the curricula have to follow.

Key messages

Students need global health education to respond to global health-related challenges. Volunteer student-led initiatives can increase knowledge and interest and be an important driver for change towards improving global health education.

Toxicokinetic Models for Bioconcentration of Organic Contaminants in Two Life Stages of White Sturgeon (Acipenser transmontanus)

The white sturgeon (Acipenser transmontanus) is an endangered ancient fish species that is known to be particularly sensitive to certain environmental contaminants, partly because of the uptake and subsequent toxicity of lipophilic pollutants prone to bioconcentration as a result of their high lipid content. To better understand the bioconcentration of organic contaminants in this species, toxicokinetic (TK) models were developed for the embryo-larval and subadult life stages. The embryo-larval model was designed as a one-compartment model and validated using whole-body measurements of benzo[a]pyrene (B[a]P) metabolites from a waterborne exposure to B[a]P. A physiologically based TK (PBTK) model was used for the subadult model. The predictive power of the subadult model was validated with an experimental data set of four chemicals. Results showed that the TK models could accurately predict the bioconcentration of organic contaminants for both life stages of white sturgeon within 1 order of magnitude of measured values. These models provide a tool to better understand the impact of environmental contaminants on the health and the survival of endangered white sturgeon populations.

Localization of ST-elevation on ECG is associated with regional myocardial fibrosis in acute myocarditis

Funding Acknowledgements

Type of funding sources: None.

Introduction

Both ST elevation (STE) on ECG and late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) are related to poor outcome in myocarditis.

Purpose

We evaluated if there is an association between regional STE and LGE pattern in patients with suspected myocarditis.

Methods

51 patients (42 male, 32 ± 13 years old) underwent 12-lead ECG and CMR with LGE due to suspected myocarditis. &gt;1mm STE was assessed in the antero-septal (V1-V4, aVR), inferior (II, III, aVF) and lateral (I, aVL, V5-V6) localizations. LGE was quantified as visual presence score (VPS) (1-17) and visual transmurality score (VTS) (1-68) on CMR, according to the 17-segment AHA model. STE and LGE were correlated using linear regression analysis. 

Results

31% of the patients had STE on admission ECG and a median VPS of 3 (IQR: 1-5) and VTS of 6 (IQR: 3-11) on CMR. STE showed an association with VPS and VTS in univariate and multivariate analysis (p &lt; 0.001 all). STE was most frequent in the lateral and inferior leads (48% and 31%) which correlated with regional VPS and VTS in univariate model (p &lt; 0.05 all), and remained significant in multivariate analysis for VPS (p &lt; 0.05 both). STE was less frequent in the antero-septal region (21%, where no association between LGE and STE could be revealed (p &gt; 0.05 all).

Conclusions

 Inferior and lateral STE in myocarditis is associated with regional LGE on CMR, which is an indicator of myocardial fibrosis and possible poor outcome. Our results need not be validated on larger cohorts with follow-up.

Myocardial fibrosis quantification methods by cardiovascular magnetic resonance imaging with contrast-enhancement in patients with Fabry disease

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): National Agency for Academic Exchange (NAWA).

Background. Presence and extent of late gadolinium enhancement (LGE) in patients with Fabry disease (FD) is a predictor of adverse cardiac events. However there is no gold standard method to quantify the amount of myocardial fibrosis in cardiac magnetic resonance imaging (CMR).

Purpose. The aim of this study was to establish the most reliable and reproducible technique for quantifying LGE in patients with FD.

Methods. 68 patients with FD (40% male, 40 ± 16 years old) treated in our outpatient clinic, who underwent CMR with administration of 0.2 mmol of gadobutrol per kilogram of body weight between December 2012 and March 2019 were enrolled into the study. Presence of LGE was described in 25 patients (37%). Twenty patients underwent CMR with the same LGE sequence (Philips 1.5 Tesla, two-dimensional multi-breath-hold inversion recovery sequence) and were enrolled into further analysis. LGE quantifications were performed using gray-scale thresholds with 2, 3, 4, 5 and 6 standard deviations (SD) above the mean signal intensity for the remote myocardial tissue, full width at half maximum method (FWHM), visual assessment with threshold (VAT) and fully manual method (MM; Philips IntelliSpace Portal 10). LGE quantifications were done twice by the same observer in different time periods and once by another observer. Intraclass correlation coefficient (ICC), Bland- Altman analysis and coefficient of variation (CV) were used to assess intra- and interobserver reliability and reproducibility.

Results. The mean quantity of fibrosis mass  (in gram) in all studied patients was: 35.5 ± 18.7 at 2SD, 21.0 ± 12.8 at 3SD, 12.7 ± 8.5 at 4SD, 8.0 ± 5.7 at 5SD, 5.3 ± 4.1 at 6SD, 1.9 ± 1.8 at FWHM, 8.6 ± 7.4 at VAT and 9.1 ± 6.1 at MM. Intra-observer reliability of almost all studied LGE quantification methods was excellent, with a range of ICCs from 0.90 for 6SD to 0.95 for VAT, with one exception for FWHM, which had good intraobserver reliability (ICC 0.84; all P &lt; 0.05). Interobserver reliability was excellent for VAT (ICC 0.94) and good for all other LGE quantifications methods (range of ICCs from 0.76 for MM to 0.87 for 5SD, all P &lt; 0.05). 5SD had the lowest CV (6%) for intraobserver reproducibility and 2SD and VAT for interobserver reproducibility (35% and 38%). FWHM had the highest CV for both intra- and interobserver reproducibility (63% and 94%, accordingly).

Conclusions

1. All studied methods of LGE quantification in patients with FD and presence of myocardial fibrosis have good to excellent intra- and interobserver reliability.

2. The total amount of LGE differs in studied LGE quantifications methods. Therefore in clinical practice it is important to report which technique of LGE quantification was used and choose the same for CMR-follow up.

3. FWHM might be avoided for LGE quantification in patients with FD due to the highest intra- and interobserver variability in comparison to other available techniques.

A Novel Multispecies Toxicokinetic Modeling Approach in Support of Chemical Risk Assessment

Standardized laboratory tests with a limited number of model species are a key component of chemical risk assessments. These surrogate species cannot represent the entire diversity of native species, but there are practical and ethical objections against testing chemicals in a large variety of species. In previous research, we have developed a multispecies toxicokinetic model to extrapolate chemical bioconcentration across species by combining single-species physiologically based toxicokinetic (PBTK) models. This "top-down" approach was limited, however, by the availability of fully parameterized single-species models. Here, we present a "bottom-up" multispecies PBTK model based on available data from 69 freshwater fishes found in Canada. Monte Carlo-like simulations were performed using statistical distributions of model parameters derived from these data to predict steady-state bioconcentration factors (BCFs) for a set of well-studied chemicals. The distributions of predicted BCFs for 1,4-dichlorobenzene and dichlorodiphenyltrichloroethane largely overlapped those of empirical data, although a tendency existed toward overestimation of measured values. When expressed as means, predicted BCFs for 26 of 34 chemicals (82%) deviated by less than 10-fold from measured data, indicating an accuracy similar to that of previously published single-species models. This new model potentially enables more environmentally relevant predictions of bioconcentration in support of chemical risk assessments.

A quantum magnetic analogue to the critical point of water

At the liquid-gas phase transition in water, the density has a discontinuity at atmospheric pressure; however, the line of these first-order transitions defined by increasing the applied pressure terminates at the critical point¹, a concept ubiquitous in statistical thermodynamics². In correlated quantum materials, it was predicted³ and then confirmed experimentally^4,5 that a critical point terminates the line of Mott metal-insulator transitions, which are also first-order with a discontinuous charge carrier density. In quantum spin systems, continuous quantum phase transitions⁶ have been controlled by pressure^7,8, applied magnetic field^9,10 and disorder¹¹, but discontinuous quantum phase transitions have received less attention. The geometrically frustrated quantum antiferromagnet SrCu₂(BO₃)₂ constitutes a near-exact realization of the paradigmatic Shastry-Sutherland model^12-14 and displays exotic phenomena including magnetization plateaus¹⁵, low-lying bound-state excitations¹⁶, anomalous thermodynamics¹⁷ and discontinuous quantum phase transitions^18,19. Here we control both the pressure and the magnetic field applied to SrCu₂(BO₃)₂ to provide evidence of critical-point physics in a pure spin system. We use high-precision specific-heat measurements to demonstrate that, as in water, the pressure-temperature phase diagram has a first-order transition line that separates phases with different local magnetic energy densities, and that terminates at an Ising critical point. We provide a quantitative explanation of our data using recently developed finite-temperature tensor-network methods^17,20-22. These results further our understanding of first-order quantum phase transitions in quantum magnetism, with potential applications in materials where anisotropic spin interactions produce the topological properties^23,24 that are useful for spintronic applications.

Workplace stress and discrimination effects on the physical and depressive symptoms of underrepresented minority faculty

Evidence-based research and interventions to address systemic institutional racism have never been more urgent. Yet, underrepresented minority (URM) professionals in research institutions who primarily produce that evidence have remained abysmally low for decades. This unique study of URM university professors assesses factors-vocational strain, role overload, discrimination, coping strategies-that contribute to health and well-being, research productivity, and ultimately their retention in high impact research positions. We administered a web-based survey assessing demographics, workplace stressors, perceived discrimination, life events, coping strategies, and physical and depressive symptoms. Study participants include 404 faculty of whom 254 are African Americans, 99 are Mexican Americans, and 51 are Puerto Ricans. Hierarchical regression analyses were employed to assess the associations between workplace stress, coping strategies, and symptoms. Results show that perceived discrimination, vocational strain, role overload, and life events directly affected physical symptoms, with self-care (p < 0.001) moderating these effects. Vocational strain and life events had direct effects on depressive symptoms with self-care (p < 0.05) and social support (p < 0.001) moderating these effects. Findings inform health care providers and university leaders about work stress and health conditions that may explain early morbidity and premature departures of URM faculty, and proffer institutional interventions to retain these faculty.

Menoci: lightweight extensible web portal enhancing data management for biomedical research projects

BACKGROUND

Biomedical research projects deal with data management requirements from multiple sources like funding agencies' guidelines, publisher policies, discipline best practices, and their own users' needs. We describe functional and quality requirements based on many years of experience implementing data management for the CRC 1002 and CRC 1190. A fully equipped data management software should improve documentation of experiments and materials, enable data storage and sharing according to the FAIR Guiding Principles while maximizing usability, information security, as well as software sustainability and reusability.

RESULTS

We introduce the modular web portal software menoci for data collection, experiment documentation, data publication, sharing, and preservation in biomedical research projects. Menoci modules are based on the Drupal content management system which enables lightweight deployment and setup, and creates the possibility to combine research data management with a customisable project home page or collaboration platform.

CONCLUSIONS

Management of research data and digital research artefacts is transforming from individual researcher or groups best practices towards project- or organisation-wide service infrastructures. To enable and support this structural transformation process, a vital ecosystem of open source software tools is needed. Menoci is a contribution to this ecosystem of research data management tools that is specifically designed to support biomedical research projects.

Mitral annular calcification in the elderly - Quantitative assessment

PURPOSE

To determine the reliability of subjective and objective quantification of mitral annular calcification (MAC) in elderly patients with severe aortic stenosis, to define quantitative sex- and age-related reference values of MAC, and to correlate quantitative MAC with mitral valve disease.

METHODS

In this retrospective, IRB-approved study, we included 559 patients (268 females, median age 81 years, inter-quartile range 77-85 years) with severe aortic stenosis undergoing CT. Four independent readers performed subjective MAC categorization as follows: no, mild, moderate, and severe MAC. Two independent readers performed quantitative evaluation of MAC using the Agatston score method (Agatston_MAC). Mitral valve disease was determined by echocardiography.

RESULTS

Subjective MAC categorization showed high inter-reader agreement for no (k ​= ​0.88) and severe MAC (k ​= ​0.75), whereas agreement for moderate (k ​= ​0.59) and mild (k ​= ​0.45) MAC was moderate. Intra-reader agreement for subjective MAC categorization was substantial (k ​= ​0.69 and 0.62). Inter- and intra-reader agreement for Agatston_MAC were excellent (ICC ​= ​0.998 and 0.999, respectively), with minor inconsistencies in MAC involving the left ventricular outflow tract/aortic valve. There were significantly more women than men with MAC (n ​= ​227, 85% versus n ​= ​209, 72%; p ​< ​0.001), with a significantly higher Agatston_MAC (median 597, range 81-2055 versus median 244; range 0-1565; p ​< ​0.001), particularly in patients ≥85 years of age. Agatston_MAC showed an area-under-the-curve of 0.84 to diagnose mitral stenosis, whereas there was no association of Agatston_MAC with mitral regurgitation (p ​> ​0.05).

CONCLUSIONS

Our study in elderly patients with severe aortic stenosis shows that quantitative MAC scoring is more reliable than subjective MAC assessment. Women show higher Agatston_MAC scores than men, particularly in the elderly population. Agatston_MAC shows high accuracy to diagnose mitral stenosis.

Efficacy of antiseptics in a novel 3-dimensional human plasma biofilm model (hpBIOM)

The increasing incidence of non-healing wounds constitutes a pivotal socio-economic burden. 60-80% of chronic wounds are colonized by pathogenic microorganisms within a protective extracellular polymeric substance, bearing a great challenge in wound management. Human plasma was used to prepare the biofilm model (hpBIOM), adding pathogens to the plasma and forming Coagula-like discs with integrated pathogens were produced. The antiseptics Octenisept and Lavasorb were tested regarding their antibacterial properties on clinically relevant biofilm-growing bacteria (MRSA, P. aeruginosa) in the hpBIOM. Biofilm-typical glycocalyx-formation was confirmed using immunohistochemical staining. Treatment of a 12 h-maturated biofilm with Octenisept resulted in complete eradication of P. aeruginosa and MRSA after 48 h. Lavasorb proved less effective than Octenisept in this setting. In more mature biofilms (24 h), both antiseptics showed a delayed, partially decreased efficacy. Summarized, the hpBIOM provides essential factors for a translational research approach to be used for detailed human biofilm analyses and evaluation of antimicrobial/-biofilm properties of established and novel therapeutic strategies and products. Octenisept and Lavasorb showed an attenuated efficacy in the hpBIOM compared to planktonic conditions and previously published biofilm-studies, prompting the question for the necessity of introducing new international standards and pre-admission requirements on a translational base.

Evaluating anticoagulation sensitivity among elderly patients managed with an institution’s heparin protocol using initial anti-factor Xa levels

Purpose

The purpose of this study was to assess an institution’s heparin protocols in elderly and nonelderly adult populations to see if a response difference was observed.

Methods

This was a retrospective cohort study of hospitalized adults who were prescribed unfractionated heparin due to surgery, acute coronary syndrome (ACS), or deep vein thrombosis/pulmonary embolism (DVT/PE) from February 11, 2016, through August 1, 2017. Patients were divided into nonelderly adults 18 to 69 years of age and elderly patients 70 years of age or older. The anti-factor Xa (anti-Xa) level after protocol initiation was compared to the institution’s goal range of 0.3 to 0.7 IU/mL. Outcomes of each protocol in the elderly population were compared to outcomes in their nonelderly counterparts to determine if there was a difference in heparin response.

Results

A total of 325 patients were included in the analysis, comprising 150 elderly and 175 nonelderly adults. Elderly patients had a higher initial anti-Xa levels than did their nonelderly adult counterparts in the ACS, DVT/PE, and surgery protocols, with P values of 0.02, &lt;0.001, and 0.01, respectively. Only the ACS protocol demonstrated increased frequency of above-target-level anti-Xa levels in the elderly (P = 0.03).

Conclusion

Elderly patients had significantly higher initial anti-Xa levels than did nonelderly adult patients across all protocols. This study identifies the need to further study elderly patients’ increased heparin sensitivity to determine if a separate dosing protocol is needed.

Autoimmunhämolytische Anämie als seltene Nebenwirkung einer Therapie mit Pembrolizumab bei metastasiertem Melanom

Checkpoint-Inhibitoren wie Pembrolizumab, Nivolumab und Ipilimumab stellen unverzichtbare Wirkstoffe zur Behandlung fortgeschrittener oder metastasierter Melanome dar. Durch eine Aktivierung zytotoxischer T-Zellen durch diese Substanzen kommt es neben einer antitumoralen Immunantwort bei vielen Patienten auch zu einer Vielzahl an immunvermittelten Nebenwirkungen, die jedes Organ des Körpers betreffen können. Neben häufigen autoimmun vermittelten Nebenwirkungen, wie z. B. einer Kolitis, einer Pneumonitis, einer Thyreoiditis und einer Hypophysitis, die in der Regel rasch erkannt werden, können auch seltene Nebenwirkungen auftreten, die initial oft nicht direkt als Nebenwirkung der Therapie interpretiert werden.

Bei einer 66 Jahre alten Patientin wurde ein Melanom am linken Unterschenkel exzidiert (Typ NMM, Tumordicke 3 mm; BRAF, NRAS und c-Kit jeweils Wildtyp), Sentinelnodebiopsie inguinal positiv, darauffolgende Lymphknotendissektion ohne Metastasennachweis. Sechs Monate später traten inguinale Lymphknotenfiliae sowie mehrere kutane Metastasen am linken Bein auf. Es erfolgte eine knappe Resektion in toto mit anschließender adjuvanter Radiatio (inguinal und Knie links, GRD 45 Gy). Bereits einige Wochen später zeigten sich am linken Bein erneut mehrere kutane Filiae sowie Lymphknotenfiliae inguinal und iliakal links. Aufgrund des mittlerweile ausgebildeten massiven Lymphödems wurde bei nicht-operabler, lokoregionärer Metastasierung 2016 eine Therapie mit Pembrolizumab begonnen.

Nach der 12. Gabe bildete sich eine normochrome, normozytäre Anämie mit transfusionsbedürftigem Hämoglobin (Hb)-Abfall bis auf 8,4 mg/dl aus. Gastro- und koloskopisch konnte keine Blutungsquelle nachgewiesen werden, mittels Knochenmarksbiopsie wurden eine Infiltration des Knochenmarks durch Melanomzellen sowie eine Pure Red Cell Aplasia ausgeschlossen. Bei erhöhter LDH, erniedrigten Werten für Haptoglobin und Retikulozyten sowie positivem direkten Coombs-Test für c3d wurde die Diagnose einer autoimmunhämolytischen Anämie (AIHA) mit Beteiligung aller Vorstufen der roten Reihe gestellt und eine Therapie mit Methylprednisolon begonnen. Bei jedem Versuch die Therapie mit Pembrolizumab nach Stabilisierung des Hb-Wertes fortzuführen, zeigte sich ein erneuter transfusionsbedürftiger Abfall auf Hb-Werte von bis zu 6 mg/dl. Wir entschieden uns die Therapie mit Pembrolizumab nach 15 Zyklen bei kompletter Remission der Metastasen zu beenden; seitdem zeigen sich in Laborkontrollen normwertige Hb-Werte. Da sich nach einigen Monaten erneut ein Progress ausbildete, wurde bei negativem BRAF-Mutationsstatus eine Therapie mit Nivolumab begonnen, hierunter kam es nicht zur erneuten Ausbildung einer AIHA.

Die Entwicklung einer Anämie ist eine seltene Nebenwirkung einer Therapie mit Checkpoint-Inhibitoren. Als weitere Ursache wurde neben der hier gezeigten AIHA auch die aplastische Anämie als immunvermittelte Nebenwirkung beschrieben.

In den wenigen bisher publizierten Fällen bildete sich die Anämie i. R. der Therapie mit Checkpoint-Inhibitoren frühzeitig aus und zeigte oft ein zögerliches Ansprechen auf Steroide. Bisher sind nur wenige Fälle beschrieben, bei denen eine Re-Exposition ohne erneutes Aufflammen der Anämie möglich war. Trotz immunsuppressiver Therapie sind letale Verläufe beschrieben. Dies verdeutlicht die Notwendigkeit regelmäßiger Laboruntersuchungen unter und nach der Therapie mit Checkpoint-Inhibitoren. In unserem Fall kam es erfreulicherweise nach erneuter Gabe eines Checkpoint-Inhibitors nicht zum erneuten Auftreten der AIHA. Ob dies dem Wechsel von Pembrolizumab zu Nivolumab geschuldet ist, muss derzeit leider unbeantwortet bleiben.

[Auditory group therapy in adult cochlear implant rehabilitation]

BACKGROUND

Auditory training is an established intervention in adult cochlear implant (CI) aural rehabilitation. In most cases, training is implemented in an individual therapy setting. Increasing patient numbers and the associated time-economic and cost-related demands as well as psychosocial and communicative aspects support the use of aural group interventions.

OBJECTIVES

This study aimed 1) to describe concepts and contents of group interventions for adult CI users and 2) to present results of a questionnaire-based evaluation.

METHODS

Group interventions have been offered at the CI Centre Erlangen CICERO for several years. In Auditory Training Groups, exercises have priority, while Thematic Group Workshops focus on psychosocial aspects and provide information for the participants. The Auditory Training Groups were evaluated based on a patient questionnaire. Additionally, the reliability of the questionnaire was analyzed.

RESULTS

The median overall satisfaction of CI users participating in Auditory Training Groups was rated as good. Training of speech perception in noise as well as communicative exchange are of great importance for CI users. They rated the therapeutic design as very good to good. Reliability analysis showed significant positive intercorrelations of the questionnaire items.

CONCLUSION

Group interventions are well accepted by CI users and represent a useful complement to individual therapy during the rehabilitation process. As group interventions place special demands on patients and therapists, structured and well-proven concepts should be used in practice.

Impact of probiotics on pathogen survival in an innovative human plasma biofilm model (hpBIOM)

BACKGROUND

Despite of medical advances, the number of patients suffering on non-healing chronic wounds is still increasing. This fact is attended by physical and emotional distress and an economic load. The majority of chronic wounds are infected of harmful microbials in a protecting extracellular matrix. These biofilms inhibit wound healing. Biofilm-growing bacteria developed unique survival properties, which still challenge the appropriate wound therapy. The present in-vitro biofilm models are not suitable for translational research. By means of a novel in-vivo like human plasma biofilm model (hpBIOM), this study systematically analysed the influence of 3 probiotics on the survival of five clinically relevant pathogenic microorganisms.

METHODS

Human plasma was used to produce the innovate biofilm. Pathogenic microorganisms were administered to the plasma. By stimulating the production of a fibrin scaffold, stable coagula-like discs with integrated pathogens were produced. The five clinically relevant pathogens P. aeruginosa, S. aureus, S. epidermidis, E. faecium and C. albicans were challenged to the probiotics L. plantarum, B. lactis and S. cerevisiae. The probiotics were administered on top of the biofilm and the survival was quantified after 4 h and 24 h of incubation. For statistics, two-way ANOVA with post-hoc Tukey's HSD test was applied. P-value > 0.05 was considered to be significant.

RESULTS

SEM micrographs depicted the pathogens on the surface of the fibrin scaffold, arranged in close proximity and produced the glycocalyx. The application of probiotics induced different growth-reducing capacities towards the pathogens. B. lactis and S. cerevisiae showed slight bacteria-reducing properties. The survival of C. albicans was not affected at all. The most antimicrobial activity was detected after the treatment with L. plantarum.

CONCLUSIONS

This study successfully reproduced a novel human biofilm model, which provides a human wound milieu and individual immune competence. The success of bacteriotherapy is dependent on the strain combination, the number of probiotics and the activity of the immune cells. The eradicating effect of L. plantarum on P. aeruginosa should be emphasized.

Biodistribution of strontium and barium in the developing and mature skeleton of rats

Bone acts as a reservoir for many trace elements. Understanding the extent and pattern of elemental accumulation in the skeleton is important from diagnostic, therapeutic, and toxicological perspectives. Some elements are simply adsorbed to bone surfaces by electric force and are buried under bone mineral, while others can replace calcium atoms in the hydroxyapatite structure. In this article, we investigated the extent and pattern of skeletal uptake of barium and strontium in two different age groups, growing, and skeletally mature, in healthy rats. Animals were dosed orally for 4 weeks with either strontium chloride or barium chloride or combined. The distribution of trace elements was imaged in 3D using synchrotron K-edge subtraction micro-CT at 13.5 µm resolution and 2D electron probe microanalysis (EPMA). Bulk concentration of the elements in serum and bone (tibiae) was also measured by mass spectrometry to study the extent of uptake. Toxicological evaluation did not show any cardiotoxicity or nephrotoxicity. Both elements were primarily deposited in the areas of active bone turnover such as growth plates and trabecular bone. Barium and strontium concentration in the bones of juvenile rats was 2.3 times higher, while serum levels were 1.4 and 1.5 times lower than adults. In all treatment and age groups, strontium was preferred to barium even though equal molar concentrations were dosed. This study displayed spatial co-localization of barium and strontium in bone for the first time. Barium and strontium can be used as surrogates for calcium to study the pathological changes in animal models of bone disease and to study the effects of pharmaceutical compounds on bone micro-architecture and bone remodeling in high spatial sensitivity and precision.

Special topic: The association between pulse ingredients and canine dilated cardiomyopathy: addressing the knowledge gaps before establishing causation

In July 2018, the Food and Drug Administration warned about a possible relationship between dilated cardiomyopathy (DCM) in dogs and the consumption of dog food formulated with potatoes and pulse ingredients. This issue may impede utilization of pulse ingredients in dog food or consideration of alternative proteins. Pulse ingredients have been used in the pet food industry for over 2 decades and represent a valuable source of protein to compliment animal-based ingredients. Moreover, individual ingredients used in commercial foods do not represent the final nutrient concentration of the complete diet. Thus, nutritionists formulating dog food must balance complementary ingredients to fulfill the animal's nutrient needs in the final diet. There are multiple factors that should be considered, including differences in nutrient digestibility and overall bioavailability, the fermentability and quantity of fiber, and interactions among food constituents that can increase the risk of DCM development. Taurine is a dispensable amino acid that has been linked to DCM in dogs. As such, adequate supply of taurine and/or precursors for taurine synthesis plays an important role in preventing DCM. However, requirements of amino acids in dogs are not well investigated and are presented in total dietary content basis which does not account for bioavailability or digestibility. Similarly, any nutrient (e.g., soluble and fermentable fiber) or physiological condition (e.g., size of the dog, sex, and age) that increases the requirement for taurine will also augment the possibility for DCM development. Dog food formulators should have a deep knowledge of processing methodologies and nutrient interactions beyond meeting the Association of American Feed Control Officials nutrient profiles and should not carelessly follow unsubstantiated market trends. Vegetable ingredients, including pulses, are nutritious and can be used in combination with complementary ingredients to meet the nutritional needs of the dog.

Bacterial viability in oral biofilm after tooth brushing with amine fluoride or sodium fluoride

OBJECTIVE

The aim of this study was to investigate the effects of sodium fluoride (NaF) and amine fluoride (AmF) on bacterial viability in the oral cavity.

MATERIAL AND METHODS

Healthy subjects brushed their teeth with either fluoride free toothpaste, NaF- or AmF-containing toothpaste. Biofilm smears from different locations were collected before and immediately and 30 and 120 min after tooth brushing. The smears were stained with live/dead bacterial staining, and the number of the respective bacteria was counted. The data were statistically analyzed by comparing the numbers of bacteria before and after the application of no fluoride, NaF and AmF.

RESULTS

The highest numbers of bacteria were found in the tongue biofilm, followed by the palatal and cheek biofilm. The lowest numbers were found in the mouth floor biofilm. After the application of AmF, no changes in the numbers of bacteria were found in the biofilms, except for the cheek, where they were reduced. After the application of NaF, the number of bacteria decreased significantly in all biofilms. After 120 min, bacterial regrowth was complete.

CONCLUSIONS

AmF has only little effect on the bacterial viability of oral biofilms. NaF application reduces the number of living bacteria in the oral biofilms. This effect lasts not longer than 120 min.

The odd couple: using biomedical and intersectional approaches to address health inequities

Background: Better understanding and addressing health inequities is a growing global priority.

Objective: In this paper, we contribute to the literature examining complex relationships between biological and social dimensions in the field of health inequalities. Specifically, we explore the potential of intersectionality to advance current approaches to socio-biological entwinements.

Design: We provide a brief overview of current approaches to combining both biological and social factors in a single study, and then investigate the contributions of an intersectional framework to such work.

Results: We offer a number of concrete examples of how intersectionality has been used empirically to bring both biological and social factors together in the areas of HIV, post-traumatic stress disorder, female genital circumcision/mutilation/cutting, and cardiovascular disease.

Conclusion: We argue that an intersectional approach can further research that integrates biological and social aspects of human lives and human health and ultimately generate better and more precise evidence for effective policies and practices aimed at tackling health inequities.

Registration of phase-contrast images in propagation-based X-ray phase tomography

X-ray phase tomography aims at reconstructing the 3D electron density distribution of an object. It offers enhanced sensitivity compared to attenuation-based X-ray absorption tomography. In propagation-based methods, phase contrast is achieved by letting the beam propagate after interaction with the object. The phase shift is then retrieved at each projection angle, and subsequently used in tomographic reconstruction to obtain the refractive index decrement distribution, which is proportional to the electron density. Accurate phase retrieval is achieved by combining images at different propagation distances. For reconstructions of good quality, the phase-contrast images recorded at different distances need to be accurately aligned. In this work, we characterise the artefacts related to misalignment of the phase-contrast images, and investigate the use of different registration algorithms for aligning in-line phase-contrast images. The characterisation of artefacts is done by a simulation study and comparison with experimental data. Loss in resolution due to vibrations is found to be comparable to attenuation-based computed tomography. Further, it is shown that registration of phase-contrast images is nontrivial due to the difference in contrast between the different images, and the often periodical artefacts present in the phase-contrast images if multilayer X-ray optics are used. To address this, we compared two registration algorithms for aligning phase-contrast images acquired by magnified X-ray nanotomography: one based on cross-correlation and one based on mutual information. We found that the mutual information-based registration algorithm was more robust than a correlation-based method.

Medium-chain fatty acids modulate myocardial function via a cardiac odorant receptor

Several studies have demonstrated the expression of odorant receptors (OR) in various human tissues and their involvement in different physiological and pathophysiological processes. However, the functional role of ORs in the human heart is still unclear. Here, we firstly report the functional characterization of an OR in the human heart. Initial next-generation sequencing analysis revealed the OR expression pattern in the adult and fetal human heart and identified the fatty acid-sensing OR51E1 as the most highly expressed OR in both cardiac development stages. An extensive characterization of the OR51E1 ligand profile by luciferase reporter gene activation assay identified 2-ethylhexanoic acid as a receptor antagonist and various structurally related fatty acids as novel OR51E1 ligands, some of which were detected at receptor-activating concentrations in plasma and epicardial adipose tissue. Functional investigation of the endogenous receptor was carried out by Ca²⁺ imaging of human stem cell-derived cardiomyocytes. Application of OR51E1 ligands induced negative chronotropic effects that depended on activation of the OR. OR51E1 activation also provoked a negative inotropic action in cardiac trabeculae and slice preparations of human explanted ventricles. These findings indicate that OR51E1 may play a role as metabolic regulator of cardiac function.

Three-dimensional labeling of newly formed bone using synchrotron radiation barium K-edge subtraction imaging

Bone is a dynamic tissue which exhibits complex patterns of growth as well as continuous internal turnover (i.e. remodeling). Tracking such changes can be challenging and thus a high resolution imaging-based tracer would provide a powerful new perspective on bone tissue dynamics. This is, particularly so if such a tracer can be detected in 3D. Previously, strontium has been demonstrated to be an effective tracer which can be detected by synchrotron-based dual energy K-edge subtraction (KES) imaging in either 2D or 3D. The use of strontium is, however, limited to very small sample thicknesses due to its low K-edge energy (16.105 keV) and thus is not suitable for in vivo application. Here we establish proof-of-principle for the use of barium as an alternative tracer with a higher K-edge energy (37.441 keV), albeit for ex vivo imaging at the moment, which enables application in larger specimens and has the potential to be developed for in vivo imaging of preclinical animal models. New bone formation within growing rats in 2D and 3D was demonstrated at the Biomedical Imaging and Therapy bending magnet (BMIT-BM) beamline of the Canadian Light Source synchrotron. Comparative x-ray fluorescence imaging confirmed those patterns of uptake detected by KES. This initial work provides a platform for the further development of this tracer and its exploration of applications for in vivo development.

A Conceptual Framework for Understanding Race, Class, Gender, and Sexuality

Since the mid-1980s, scholarship and college courses that address multiple dimensions of inequality under the rubric of race, class, gender, and (recently) sexuality studies have grown rapidly. Most courses now employ a set of readings, many of which are drawn from a growing number of anthologies. A strength of this approach is its presentation of the diversity of human experiences and the multiplicity of critical perspectives. A weakness is its failure to convey the commonalities in race, class, gender, and sexuality analyses of social reality. To aid in teaching and research on race, class, gender, and sexuality, this article presents six common themes that characterize this scholarship. Race, class, gender, and sexuality are historically and globally specific, socially constructed power relations that simultaneously operate at both the macro (societal) and micro (individual) levels of society. Scholarship in this tradition emphasizes the interdependence of knowledge and activism.

Effects of water-soluble fraction of petroleum on growth and prey consumption of juvenile Hoplias aff. malabaricus (Osteichthyes: Erythrinidae)

The influence of the water-soluble fraction of petroleum (WSF) on prey consumption and growth of juvenile trahira Hoplias aff. malabaricus was investigated. Juveniles were submitted to either WSF or Control treatment over 28 days, and jewel tetra Hyphessobrycon eques adults were offered daily as prey for each predator. Total prey consumption ranged from 16 to 86 individuals. Despite the initially lower prey consumption under WSF exposure, there were no significant differences in overall feeding rates between the two treatments. Water-soluble fraction of petroleum had a negative effect on the growth in length of H. aff. malabaricus juveniles. Although unaffected, prey consumption suggested a relative resistance in H. aff. malabaricus to WSF exposition and the lower growth of individuals exposed to WSF than the Control possibly reflects metabolic costs. The implications of the main findings for the individual and the food chain are discussed, including behavioral aspects and the role played by this predator in shallow aquatic systems.