Differences in Discounting Behavior and Brain Responses for Food and Money Reward

Most neuroeconomic research seeks to understand how value influences decision-making. The influence of reward type is less well understood. We used functional magnetic resonance imaging (fMRI) to investigate delay discounting of primary (i.e., food) and secondary rewards (i.e., money) in 28 healthy, normal-weighted participants (mean age = 26.77; 18 females). To decipher differences in discounting behavior between reward types, we compared how well-different option-based statistical models (exponential, hyperbolic discounting) and attribute-wise heuristic choice models (intertemporal choice heuristic, dual reasoning and implicit framework theory, trade-off model) captured the reward-specific discounting behavior. Contrary to our hypothesis of different strategies for different rewards, we observed comparable discounting behavior for money and food (i.e., exponential discounting). Higher k values for food discounting suggest that individuals decide more impulsive if confronted with food. The fMRI revealed that money discounting was associated with enhanced activity in the right dorsolateral prefrontal cortex, involved in executive control; the right dorsal striatum, associated with reward processing; and the left hippocampus, involved in memory encoding/retrieval. Food discounting, instead, was associated with higher activity in the left temporoparietal junction suggesting social reinforcement of food decisions. Although our findings do not confirm our hypothesis of different discounting strategies for different reward types, they are in line with the notion that reward types have a significant influence on impulsivity with primary rewards leading to more impulsive choices.

Feasibility of using real-world free thyroxine data from the US and Europe to enable fast and efficient transfer of reference intervals from one population to another

Objectives

The direct approach for determining reference intervals (RIs) is not always practical. This study aimed to generate evidence that a real-world data (RWD) approach could be applied to transfer free thyroxine RIs determined in one population to a second population, presenting an alternative to performing multiple RI determinations.

Design and methods

Two datasets (US, n = 10,000; Europe, n = 10,000) were created from existing RWD. Descriptive statistics, density plots and cumulative distributions were produced for each data set and comparisons made. Cumulative probabilities at the lower and upper limits of the RIs were identified using an empirical cumulative distribution function. According to these probabilities, estimated percentiles for each dataset and estimated differences between the two sets of percentiles were obtained by case resampling bootstrapping. The estimated differences were then evaluated against a pre-determined acceptance criterion of ≤7.8% (inter-individual biological variability). The direct approach was used to validate the RWD approach.

Results

The RWD approach provided similar descriptive statistics for both populations (mean: US = 16.1 pmol/L, Europe = 16.4 pmol/L; median: US = 15.4 pmol/L, Europe = 15.8 pmol/L). Differences between the estimated percentiles at the upper and lower limits of the RIs fulfilled the pre-determined acceptance criterion and the density plots and cumulative distributions demonstrated population homogeneity. Similar RI distributions were observed using the direct approach.

Conclusions

This study provides evidence that a RWD approach can be used to transfer RIs determined in one population to another.

The Histopathology of Leg Ulcers

Ulcerations of the lower extremities are a frequently encountered problem in clinical practice and are of significant interest in public health due to the high prevalence of underlying pathologies, including chronic venous disease, diabetes and peripheral arterial occlusive disease. However, leg ulcers can also present as signs and symptoms of various rare diseases and even as an adverse reaction to drugs. In such cases, correct diagnosis ultimately relies on histopathological examination. Apart from the macroscopic presentation, patient history and anatomic location, which are sometimes indicative, most ulcers have very distinct histopathological features. These features are found in different layers of the skin or even associated vessels. In this narrative review, we discuss and highlight the histopathological differences of several types of leg ulcers that can contribute to efficient and accurate diagnosis.

Impact of thrombosis location on walking capacity: a cohort study of patients with acute deep vein thrombosis

Background

Data on walking impairment during the acute phase of deep vein thrombosis (DVT) are limited.

Objectives

This study aimed to assess the degree of walking impairment in patients with acute DVT, with a particular focus on the relation to the DVT's anatomical location.

Methods

Patients with sonographically confirmed DVT were eligible for inclusion in this cohort study. Pain-free walking distance (PWD) and maximum walking distance (MWD) were determined using standardized treadmill ergometer tests and analyzed in relation to DVT location. The impact of previous DVT on walking capacity was evaluated in an exploratory analysis.

Results

The study included 64 patients (31% women; median age, 55 years). The median (IQR) time from diagnosis to exercise test was 3 (1-5) days. Patients with suprainguinal DVT demonstrated significantly shorter median (IQR) MWD than those with infrainguinal DVT (130 (61-202) m vs 565 (128-750) m; P < .01), while PWD did not significantly differ (PWD: 20 (0-30) m vs 40 (0-222) m; P = .14). The proportion of patients who had to terminate treadmill tests prematurely was higher in patients with suprainguinal DVT (91.7% vs 57.7%; P = .04). PWD and MWD seemed to be similar in patients with and without a history of DVT. Premature test termination and suprainguinal DVT location were associated with reduced quality of life, as measured by the EuroQoL Group 5-Dimension 5-Level questionnaire and visual analog scale.

Conclusion

Suprainguinal DVT was linked to a more pronounced walking impairment compared with infrainguinal DVT. Limited walking capacity was associated with a reduced quality of life.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Entwicklung eines Lokalisations-basierten Algorithmus zur Vorhersage der Ätiologie von Ulcera cruris

Hintergrund

Die diagnostische Abklärung des Ulcus cruris ist zeit‐ und kostenintensiv. Ziel dieser Studie war es, die Ulkuslokalisation als diagnostisches Kriterium zu bewerten und einen diagnostischen Algorithmus zur Unterstützung in der Diagnostik bereitzustellen.

Patienten und Methodik

Die Studie umfasste 277 Patienten mit Ulcera cruris. Es wurden die folgenden fünf Gruppen definiert: Ulcus cruris venosum, arterielle Ulzera, gemischte Ulzera, Arteriolosklerose und Vaskulitis. Mittels computergestütztem Oberflächenrendering wurden die Prädilektionsstellen der verschiedenen Ulkustypen bewertet. Die Ergebnisse wurden in ein multinomiales logistisches Regressionsmodell integriert, um die Wahrscheinlichkeit einer bestimmten Diagnose in Abhängigkeit von Lokalisation, Alter, bilateraler Beteiligung und Anzahl der Ulzera zu berechnen. Zusätzlich wurde eine neuronale Netzwerk‐Bildanalyse durchgeführt.

Ergebnisse

Die Mehrheit der venösen Ulzera fand sich in der medialen Malleolarregion. Arterielle Ulzera waren am häufigsten auf der dorsalen Seite des Vorfußes zu finden. Arteriolosklerotische Ulzera waren zumeist im mittleren Drittel des lateralen Unterschenkels lokalisiert. Vaskulitische Ulzera schienen zufällig verteilt zu sein und waren deutlich kleiner, häufiger multilokulär und bilateral. Das multinomiale logistische Regressionsmodell zeigte eine insgesamt zufriedenstellende Leistung mit einer geschätzten Genauigkeit von 0,68 bei ungesehenen Daten.

Schlussfolgerungen

Der vorgestellte Algorithmus auf Grundlage der Ulkuslokalisation kann als unterstützendes Instrument zur Eingrenzung potenzieller Differenzialdiagnosen und als Hilfestellung für die Einleitung diagnostischer Maßnahmen dienen.

Development of a localization-based algorithm for the prediction of leg ulcer etiology

BACKGROUND

Diagnostic work-up of leg ulcers is time- and cost-intensive. This study aimed at evaluating ulcer location as a diagnostic criterium and providing a diagnostic algorithm to facilitate differential diagnosis.

PATIENTS AND METHODS

The study consisted of 277 patients with lower leg ulcers. The following five groups were defined: Venous leg ulcer, arterial ulcers, mixed ulcer, arteriolosclerosis, and vasculitis. Using computational surface rendering, predilection sites of different ulcer types were evaluated. The results were integrated in a multinomial logistic regression model to calculate the likelihood of a specific diagnosis depending on location, age, bilateral involvement, and ulcer count. Additionally, neural network image analysis was performed.

RESULTS

The majority of venous ulcers extended to the medial malleolar region. Arterial ulcers were most frequently located on the dorsal aspect of the forefoot. Arteriolosclerotic ulcers were distinctly localized at the middle third of the lower leg. Vasculitic ulcers appeared to be randomly distributed and were markedly smaller, multilocular and bilateral. The multinomial logistic regression model showed an overall satisfactory performance with an estimated accuracy of 0.68 on unseen data.

CONCLUSIONS

The presented algorithm based on ulcer location may serve as a basic tool to narrow down potential diagnoses and guide further diagnostic work-up.

Temporal association between COVID-19 vaccination and Raynaud's phenomenon: A case series

COVID-19 vaccine-related adverse events are mostly minor to moderate, and serious events are rare. Single cases of Raynaud's phenomenon (RP) in temporal proximity to COVID-19 vaccination have been reported. Demographic data, medical history, and detailed information regarding vaccination status and RP characteristics were obtained from patients with confirmed RP after COVID-19 vaccination. Fifteen participants reported the initial manifestation of RP, which occurred in 40% after the first, in 33% after the second, and in 27% after the third vaccination. RP development and occurrence of episodes were not linked to any specific vaccine type. New onset of disease was observed in 40% of the vaccinees after BNT162b2, in 33% after mRNA-1273, and in 27% after ChAdOx1 vaccination. Three out of four participants with preexisting RP prior to COVID-19 vaccination reported aggravation in frequency and intensity after immunization. Although COVID-19 vaccination is pivotal in controlling the pandemic, the observed temporal association between vaccine administration and RP occurrence warrants global activities to support pharmacovigilance for the detection of adverse reactions, one of which may include RP.

Endovenous thermal ablation of superficial truncal veins and compression therapy results in symptom relief in venous valve aplasia

Venous valve aplasia (or valvular rarefication) is a rare cause of chronic venous insufficiency. In the present report, we have described the case of a 33-year-old man with severe symmetric lower leg edema and heaviness and pain in both lower legs. Duplex ultrasound demonstrated severe venous insufficiency in the superficial and deep venous system of both legs. Further imaging examinations supported the diagnosis of venous valvular aplasia. Treatment consisted of endovenous thermal ablation of the great saphenous vein and small saphenous vein as well as consistent compression therapy, resulting in a marked reduction of his leg edema, heaviness, and pain.

The post-VTE functional status scale for assessment of functional limitations in patients with venous thromboembolism: Construct validity and responsiveness in a prospective cohort study

BACKGROUND

A large proportion of patients experience functional limitations after an acute episode of venous thromboembolism (VTE). Recently, the post-VTE functional status (PVFS) scale was proposed to capture these limitations. We performed a prospective cohort study to validate this scale.

METHODS

The PVFS scale, PROMIS physical function 10a, EQ-5D-5L, and disease-specific quality of life (VEINES-QOL/Sym, PEmb-QoL) were assessed within three weeks of VTE diagnosis and after a median (IQR) follow-up of 13.4 (12.7-15.9) weeks. To evaluate construct validity of the PVFS scale, we determined correlations of PVFS scale with the other health measurements and investigated differences in patients above/below 70 years. Responsiveness was evaluated with a linear regression model, predicting change in PROMIS with change in PVFS scale.

RESULTS

We included 211 patients (median (IQR) age: 55.1 (44.1-67.6) years, 40 % women). Pulmonary embolism was diagnosed in 105 (49.8 %) patients and 62.6 % of events were unprovoked. The PVFS scale correlated with PROMIS physical function (Spearman's rho (r): -0.67 and -0.63, p < 0.001) and EQ-5D-5L index (r = -0.61 and -0.61, p < 0.001) at baseline and follow-up. Furthermore, PVFS correlated moderately to strongly with disease-specific quality of life. Patients >70 years had significantly higher PVFS grades at follow-up (median (IQR): 2 (0-3) vs. 1 (0-2), p = 0.010). Changes in PVFS scale over time were significantly associated with changes in PROMIS physical function.

CONCLUSIONS

The PVFS scale showed adequate construct validity and responsiveness in a prospective cohort study of patients with VTE, suggesting that it can be incorporated as additional health measurement and outcome parameter in research and clinical practice.

Thermogravimetric substrate analysis for prediction of biogas and methane yields

Biodegradability of biomass constituents is the reason for the gap between theoretical biogas/methane yield and the maximum yield obtainable in bioconversion. The prediction of biogas/methane yields by applying thermal analysis is a relatively new development in this field. The aim of this study was to develop a bioconversion model based on thermogravimetry. Eleven substrates with a specific biogas yield within the range 104 to 572 mL_N per gram of volatile solids were subjected to thermogravimetry and a multi linear regression model was developed to predict biogas and methane yields. The optimum parameters describe biogas and methane yields with a root mean square error of 58.8 and 34.3 mL_N per gram of volatile solids respectively. The coefficient of determination for these two datasets was 0.81 and 0.84. A prediction technique based on thermogravimetric analysis appears to be a good alternative to other prediction models.

AB0624 Patients with vasculitis have a high prevalence of coronary microvascular dysfunction

Background

Vasculitides are a heterogenous group of diseases characterized by intense vessel wall inflammation, endothelial injury, and systemic inflammation. Several vasculitides are associated with high risk of cardiovascular (CV) disease, an important source of morbidity and mortality in this population. This excess CV risk is attributed both to a high burden of traditional risk factors and to inflammation, but this remains poorly studied. Indeed, inflammation is a known risk factor for CV disease and implicated in coronary microvascular dysfunction (CMD) which may precede obstructive coronary artery disease (CAD).

Objectives

We sought to assess whether vasculitis is associated with CMD in the absence of obstructive CAD.

Methods

We retrospectively identified subjects with systemic vasculitis who underwent symptom prompted rest/stress myocardial perfusion PET. Patients with an abnormal myocardial perfusion study (summed stress score ≥3) or LVEF<40% were excluded. Controls were identified from the same population and matched on age, gender and cardiovascular risk factors (CAD, hypertension, dyslipidemia, diabetes mellitus, and obesity). Coronary flow reserve (CFR), was calculated as the ratio of myocardial blood flow (ml/min/g) at peak stress compared to rest. CMD was defined as CFR <2.

Results

We studied 26 vasculitis cases and 66 matched controls. The most common vasculitides were giant cell arteritis (38%), ANCA-associated vasculitis (31%), and Takayasu’s arteritis (12%). Median (IQR) time between diagnosis and PET was 6.5 (2.9, 14.2) years. Seven (27%) cases had active vascultis at the time of PET. Cases and controls were well-matched on age, sex, and CV risk factors (Table 1). Despite a similar prevalence of CV risk factors, coronary flow reserve (reflected by CMD) was abnormal in 38% of vasculitis cases compared to 15% of controls (p=0.004). The mean [SD] CFR was 19% lower in vasculitis cases vs controls (2.11 [0.5] versus 2.6 [0.7], p=0.003).

Table 1.

The presence of coronary microvasculature dysfunction in patients with systemic vasculitis without obstructive coronary artery disease

Cohort characteristicsVasculitis (n=26)Control (n=66)P-valueAge at PET, years62 (18)61 (17)0.24Time from Vasculitis Diagnosis to PET, years (median, IQR)6.5 (2.9, 14.2)n/aFemale, n (%)18 (72%)43 (65%)0.99Vasculitis CharacteristicsLarge Vessel (e.g., giant cell arteritis, Takayasu’s), n(%)13 (50%)n/an/aMedium Vessel (e.g., polyarteritis nodosa, Kawasaki’s arteritis), n(%)2 (8%)n/an/aSmall Vessel (e.g., ANCA-associated vasculitis, Henoch-Schonlein Purpura), n(%)11 (42%)n/an/aCardiovascular Risk FactorsAt DiagnosisAt PETAt PETHypertension, n (%)12 (46%)20 (71%)47 (80%)0.47Obesity, n (%)3 (12%)2 (32%)2 (32%)0.84Diabetes, n (%)3 (12%)5 (20%)13 (20%)0.99Dyslipidemia, n (%)4 (15%)15 (58%)40 (61%)0.99Known CAD, n (%)0 (0%)1 (4%)1 (2%)0.48Imaging FindingsRest myocardial blood flow, ml/min/g1.0 (0.3)1.0 (0.3)0.8Stress myocardial blood flow, ml/min/g2.1 (0.6)2.6 (1.0)0.008Coronary Flow Reserve, ml/min/g*2.1 (0.5)2.6 (0.7)0.003Coronary Microvasculature Dysfunction** (CMD), n (%)10 (38%)11 (15%)0.004

Conclusion

Patients with systemic vasculitis, even in the absence of obstructive CAD, have a high prevalence of CMD compared with non-vasculitis patients. These differences were observed despite matching cases and controls on traditional CV risk factors, highlighting the importance of other factors, such as inflammation and vasculitis treatments on CMD and CV disease in this population. CMD is a known independent risk factor for CV mortality. Future prospective studies are needed to understand the relationship between vasculitis, systemic inflammation, and CMD.

Disclosure of Interests

None declared

Comparative analysis of endovenous laser ablation versus ultrasound-guided foam sclerotherapy for the treatment of venous leg ulcers

BACKGROUND

Endovenous thermal and non-thermal therapeutic approaches have become standard of care for the treatment of venous insufficiency. However, comparative studies on its use in the population of venous leg ulcer patients are scarce.

METHODS

The present study aimed at a comparison of the efficacy of endovenous laser ablation (EVLA) and ultrasound-guided foam sclerotherapy (UGFS) for the treatment of venous leg ulcers (VUs). We retrospectively analyzed patient records of 68 patients with active VUs (C6 of the CEAP-classification), who underwent EVLA (n=33) or UGFS (n=35) between January 2001 and January 2021.

RESULTS

In 68 patients, 97 venous segments (GSV: 43, SSV: 17:, NSV: 37) were treated. Ulcer surface area at initial presentation did not differ significantly between both treatment groups (EVLA: 7.7±10.7 vs. UGFS: 8.5±16.3 cm² ; p=0.73). No significant difference regarding patient characteristics was found, with the exception of age, as patients receiving UGFS treatment were significantly older (EVLA: 61±17 vs. UGFS: 70±14 years; p=0.018). The rate of ulcer resolution was not significantly different between EVLA and UGFS groups (97.0% vs. 85.7%; p=0.20). Also, the mean time to complete ulcer healing after endovenous intervention was comparable (EVLA: 59±37 vs. UGFS: 63±41 days; p=0.68). However, the relapse rate was significantly higher for UGFS than for EVLA treated patients (31.4% vs. 3.0%; p=0.002).

CONCLUSION

Rates of ulcer resolution and ulcer healing time after endovenous intervention were comparable between both treatment modalities. However, a significantly higher relapse rate was observed in UGFS treated patients.

Topically administered purified clinoptilolite-tuff for the treatment of cutaneous wounds: a prospective, randomized phase I clinical trial

In an ageing society, chronic ulcers pose an increasingly relevant healthcare issue associated with significant morbidity and an increasing financial burden. Hence, there is an unmet medical need for novel, cost‐effective therapies that improve healing of chronic cutaneous wounds. This prospective, randomised, open‐label, phase I trial investigated the safety and tolerability of topically administered purified clinoptilolite‐tuff (PCT), mainly consisting of the naturally occurring zeolite‐mineral clinoptilolite, in artificial wounds in healthy male volunteers compared to the standard of care (SoC). We found that topically administered PCT was safe for therapeutic application in acute wounds in healthy male volunteers. No significant differences in wound healing or wound conditions were observed compared to SoC‐treated wounds. However, we found a significantly higher proportion of CD68‐positive cells and a significantly lower proportion of α‐smooth muscle actin‐positive cells in PCT‐treated wounds. Scanning electron microscopy revealed PCT particles in the restored dermis in some cases. However, these did not impede wound healing or clinical symptoms. Hence, purified PCT could represent an attractive, cost‐effective wound treatment promoting the process of healing.

Phosphorylated cingulin localises GEF-H1 at tight junctions to protect vascular barriers in blood endothelial cells

Dysfunction of vascular barriers is a critical step in inflammatory diseases. Endothelial tight junctions (TJs) control barrier function, and the cytoplasmic adaptor protein cingulin connects TJs to signalling pathways. However, local events at TJs during inflammation are largely unknown. In this study, we investigate the local response of TJ adaptor protein cingulin and its interaction with Rho guanine nucleotide exchange factor H1 (GEF-H1, also known as ARHGEF2) upon vascular barrier disruption to find a new approach to counteract vascular leak. Based on transendothelial-electrical-resistance (TEER) measurements, cingulin strengthened barrier integrity upon stimulation with histamine, thrombin and VEGF. Cingulin also attenuated myosin light chain 2 (MLC2; also known as MYL2) phosphorylation by localising GEF-H1 to cell junctions. By using cingulin phosphomutants, we verified that the phosphorylation of the cingulin head domain is required for its protective effect. Increased colocalisation of GEF-H1 and cingulin was observed in the vessels of vasculitis patients compared to those in healthy skin. Our findings demonstrate that cingulin can counteract vascular leak at TJs, suggesting the existence of a novel mechanism in blood endothelial cells that protects barrier function during disease.

Summary: Vascular leak in response to histamine, thrombin and VEGF can be counteracted by AMPK phosphorylating cingulin at its head domain. Consequential binding of GEF-H1 to tight junctions protects vascular barrier function.

Raynaud's Phenomenon after COVID-19 Vaccination: Causative Association, Temporal Connection, or Mere Bystander?

Herein, we report a case of a new-onset Raynaud's phenomenon (RP), which occurred in an otherwise healthy 31-year-old Caucasian woman, who lacked any known risk factors and associations with possible causes for secondary RP. However, 2 weeks prior to the development of RP, the patient had received her first injection of the COVID-19 vaccine containing ChAdOx1-SARS-COV-2. The patient presented with well-demarcated, white-pale, cold areas involving the middle fingers of both hands and the ring finger of the right hand, which were triggered by exposure to cold environment and accompanied by a sensation of numbness. Infrared thermography revealed notable temperature differences of up to 10.9°C between affected and nonaffected fingers. Coagulation and immunological parameters, including cryoglobulins and pathological autoantibodies, were within the normal range and antibodies to the heparin/platelet factor 4 complex not detectable. It remains unclear if the development of RP in our patient is causally related to antecedent COVID-19 vaccination; however, the temporal connection to the vaccination, the complete absence of RP in her past medical history, and the lack of any risk factors and triggers raise the suspicion of a yet unknown association with the vaccine. Whether a clear association between the development of RP and COVID-19 vaccination exists or whether RP represents a bystander effect needs to be awaited in case observational reports on RP accumulate. Given the steadily rising numbers of people receiving COVID-19 vaccinations, physicians may remain alert to still unrecognized side effects.

Drug-induced photosensitivity: culprit drugs, potential mechanisms and clinical consequences

Drug‐induced photosensitivity, the development of phototoxic or photoallergic reactions due to pharmaceuticals and subsequent exposure to ultraviolet or visible light, is an adverse effect of growing interest. This is illustrated by the broad spectrum of recent investigations on the topic, ranging from molecular mechanisms and culprit drugs through epidemiological as well as public health related issues to long‐term photoaging and potential photocarcinogenic consequences. The present review summarizes the current state of knowledge on the topic while focusing on culprit drugs and long‐term effects. In total, 393 different drugs or drug compounds are reported to have a photosensitizing potential, although the level of evidence regarding their ability to induce photosensitive reactions varies markedly among these agents. The pharmaceuticals of interest belong to a wide variety of drug classes. The epidemiological risk associated with the use of photosensitizers is difficult to assess due to under‐reporting and geographical differences. However, the widespread use of photosensitizing drugs combined with the potential photocarcinogenic effects reported for several agents has major implications for health and safety and suggests a need for further research on the long‐term effects.

Effectiveness of narrowband UVB phototherapy and psoralen plus UVA photochemotherapy in the treatment of generalized lichen planus: Results from a large retrospective analysis and an update of the literature

Background

The aim of this retrospective study was to compare the efficacy and safety of different phototherapeutic modalities in the treatment of cutaneous lichen planus (LP).

Methods

We retrospectively analyzed the chart data of 53 patients with generalized LP who had been subjected to narrowband UVB (NB‐UVB) or photochemotherapy (PUVA) between January 1997 and April 2020. Of these, 30 patients had received NB‐UVB, 18 patients oral PUVA and 5 patients bath PUVA.

Results

Fifty patients completed a full treatment course. The percentage of patients with a complete (>90% clearing) or good (51%‐90% clearing) response was similar for NB‐UVB versus PUVA (86.2% vs. 90.5%; P = 1.00). The number of exposures required for obtaining a complete or good response was also comparable for both treatment groups (NB‐UVB: 28.9 ± 12.3 vs. PUVA: 25.4 ± 10.1; P = .209). Adverse events, in particular gastrointestinal upsets, were recorded in 26.1% of patients treated with oral PUVA while none were observed with NB‐UVB.

Conclusion

The therapeutic outcome and the number of treatments required for achieving a complete or good response were comparable for NB‐UVB and PUVA; however, PUVA therapy was associated with a substantially higher rate of moderate adverse events.

Raman spectroscopy reveals collagen and phospholipids as major components of hyalinosis in the arteriolosclerotic ulcer of Martorell

BACKGROUND

Arteriolosclerotic ulcers of Martorell are histologically characterized by hyaline arteriolosclerosis resulting in concentric occlusion of the arteriolar lumina. Although several authors have previously reported on hyaline changes in hypertensive arteriolopathies, so far, little information is available on the molecular composition of hyaline wall depositions.

OBJECTIVES

This study aimed at the molecular characterization of hyaline arteriolar deposits in patients with hypertensive arteriolopathy using confocal Raman spectroscopy.

METHODS

Samples of patients diagnosed with arteriolosclerotic ulcers of Martorell were analysed using confocal Raman spectroscopy. The findings were correlated with histological analyses. Skin samples from healthy, non-hypertensive patients served as controls.

RESULTS

Confocal Raman spectroscopy analysis revealed that subendothelial hyaline deposits in arteriolosclerotic ulcers are mainly composed of collagen and phospholipids, in particular phosphatidylcholine. The presence of collagen within hyaline deposits was confirmed by Masson's Trichrome and Picrosirius Red staining. Additionally, the presence of collagen could also be shown for hypertensive nephrosclerosis. Actin was markedly decreased in hyalinized compared to control vessels, corresponding to the loss of smooth muscle cells in the process of hyalinization. This was confirmed by immunofluorescence staining for α-smooth muscle actin and desmin.

CONCLUSION

The present findings suggest that arteriolar hyaline deposits in hypertensive arteriolopathy are mainly composed of collagen and phospholipids, in particular phosphatidylcholine. Together with the concurrent absence of actin, these findings suggest that potentially critical disease mechanisms involve pressure-induced vascular smooth muscle cell apoptosis with subsequent deposition of collagen.

Differentiating Arteriolosclerotic Ulcers of Martorell from Other Types of Leg Ulcers Based on Vascular Histomorphology

Clinical differential diagnosis of arteriolosclerotic ulcers of Martorell is challenging due to the lack of clearly affirmative instrument-based diagnostic criteria. The aim of this study was to develop vascular histomorphological diagnostic criteria differentiating Martorell ulcers from other types of leg ulcers. The histomorphology of patients diagnosed with arteriolosclerotic ulcers of Martorell (n = 67) was compared with that of patients with venous leg ulcers, necrotizing leukocytoclastic vasculitis, pyoderma gangrenosum, and non-ulcerative controls (n = 15 each). In a multivariable logistic regression model, the rates of arteriolar calcification (odds ratio (OR) 42.71, 95% confidence interval (CI) 7.43–443.96, p < 0.001) and subendothelial hyalinosis (OR 29.28, 95% CI 4.88–278.21, p < 0.001) were significantly higher in arteriolosclerotic ulcers of Martorell. Arteriolar cellularity was significantly lower in Martorell ulcers than in controls (OR 0.003, 95 CI < 0.001–0.97, p = 0.05). However, the wall-to-lumen ratio was similar in all ulcers (OR 0.975, 95% CI 0.598–2.04, p = 0.929). Based on the Youden index, a wall cellularity of < 0.24 cells/100 μm² was determined as the optimum cut-off point (sensitivity 0.955, specificity 0.944). Thus, arteriolar calcification, subendothelial hyalinosis, and arteriolar cellularity revealed high discriminatory power for arteriolosclerotic ulcers of Martorell.

Domain Interactions Determine the Amyloidogenicity of Antibody Light Chain Mutants

In antibody light chain amyloidosis (AL), mutant light chains (LCs) or their variable domains (V_Ls) form fibrils, which accumulate in organs and lead to their failure. The molecular mechanism of this disease is still poorly understood. One of the key open issues is whether the mutant V_Ls and LCs differ in fibril formation. We addressed this question studying the effects of the V_L mutations S20N and R61A within the isolated V_L domain and in the full-length LC scaffold. Both V_L variants readily form fibrils. Here, we find that in the LC context, the S20N variant is protected from fibril formation while for LC R61A fibril formation is even accelerated compared to V_L R61A. Our analyses revealed that the partially unfolded state of the V_L R61A domain destabilizes the C_L domain by non-native interactions, in turn leading to a further unfolding of the V_L domain. In contrast, the folded mutant V_L S20N and V_L wt form native interactions with C_L. These are beneficial for LC stability and promote amyloid resistance. Thus the effects of specific mutations on the V_L fold can have opposing effects on LC domain interactions, stability and amyloidogenicity.

Association of inflammatory disease and long-term outcomes among young adults with myocardial infarction: the Partners YOUNG-MI registry

Background

Autoimmune systemic inflammatory diseases are associated with an increased risk of cardiovascular disease, particularly myocardial infarction (MI). However, there are limited data on the prevalence and effects of inflammatory disease among U.S. adults who experience an MI at a young age.

Purpose

We sought to determine the prevalence and prognostic value of inflammatory disease in U.S. adults who experience an MI at a young age.

Methods

The YOUNG-MI registry is a retrospective cohort study of consecutive patients who experienced a Type 1 MI at or below the age of 50 years from 2000 to 2016 at two large medical centers. A diagnosis of rheumatoid arthritis (RA), psoriasis (PsO), systemic lupus erythematosus (SLE), or inflammatory arthritis was determined through physician review of electronic medical records (EMR). Demographic information, presence of cardiovascular (CV) risk-factors, medical procedures, and medications upon discharge were also ascertained from the EMR. Incidence of death was determined using a combination of EMR and national databases. Cox proportional hazard modeling was performed on a sub-sample following Mahalanobis Distance matching on age, sex, and CV risk factors.

Results

The cohort consisted of 2097 individuals (median age 45 years, 19% female, 53% ST-elevation MI). Among these, 53 (2.5%) individuals possessed a diagnosis of systemic inflammatory disease at or before their index MI (23% SLE, 9% RA, 64% PsO, 4% inflammatory arthritis). When compared to the remainder of the cohort, patients with a diagnosis of systemic inflammatory disease were more likely to be female (36% vs 19%, p=0.004) and be diagnosed with hypertension (62% vs 46%, p=0.025). There was, however, no significant difference in the prevalence of other CV risk factors – diabetes, smoking, dyslipidemia – or a family history of premature coronary artery disease. Despite these similarities, patients with inflammatory disease were less likely to be prescribed aspirin (88% vs 95%, p=0.049) or a statin (76% vs 89%, p=0.008) upon discharge. Over a median follow-up of 11.2 years, patients with inflammatory disease experienced an increased risk of all-cause mortality when compared with the full-cohort (Figure). Compared to the matched sample (n=138), patients with systemic inflammatory disease exhibited an increased risk of all-cause mortality (HR=2.68, CI [1.18 to 6.07], p=0.018), which remained significant after multivariable adjustment for length of stay and GFR (HR=2.38, CI [1.02 to 5.54], p=0.045).

Conclusions

Among individuals who experienced an MI at a young age, approximately 2.5% had evidence of a systemic inflammatory disease at or before their MI. When compared with a population of individuals with similar cardiovascular risk profiles, those with inflammatory disease had higher rates of all-cause mortality. Our findings suggest that the presence of a systemic inflammatory disorder is independently associated with worse long-term outcomes.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): 1. 5T32 HL094301 NIH T32 Training Grant, “Noninvasive Cardiovascular Imaging Research Training Program”

Coronary vasomotor dysfunction is associated with worse outcomes in patients with inflammatory disease

Background

Rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and psoriasis (PsO) are common inflammatory conditions with excess cardiovascular (CV) risk compared to the general population. This excess CV risk is associated with traditional risk factors, glucocorticoid treatment, and systemic inflammation. Systemic inflammation perturbs endothelial function and has been linked to coronary vasomotor dysfunction. It is not clear if coronary vasomotor dysfunction would be associated with worse clinical outcomes in systemic autoimmune inflammatory conditions.

Purpose

We tested the hypothesis that impaired coronary flow reserve (CFR), which in the absence of flow-limiting obstructive coronary artery disease (CAD) reflects vasomotor dysfunction, among patients with SLE, RA, and PsO is associated with worse clinical outcomes.

Methods

We included patients with RA, SLE, and PsO who underwent clinically indicated rest/stress myocardial perfusion positron emission tomography (PET) at a large academic medical center from 2006 to 2019. Patients with an abnormal myocardial perfusion study (summed stress score &gt;3) or left ventricular ejection fraction &lt;40% were excluded. CFR was calculated as the ratio of myocardial blood flow (MBF, ml/min/g) at peak stress compared to the MBF at rest and adjusted for baseline heart rate and blood pressure.

Results

Among the 175 patients (median age 65.1 years, 80% female) in the cohort, 24% had SLE, 35% PsO, and 41% RA. There was no difference in mean CFR between patients with RA, SLE, or PsO. Over a median follow-up of 8.5 years after PET, there were 47 deaths. Patients in the lowest and middle tertile (CFR &lt;2.18) had a higher all-cause mortality when compared with the highest (Figure 1), and this association remained significant after adjusting for age and a composite clinical score incorporating sex, symptoms, and CV risk factors (lowest vs. highest tertile: HR 2.8; 95% confidence interval 1.2–6.5; p=0.01). CV risk factors such as diabetes, hypertension, obesity, tobacco use, and a family history of CAD were not significantly different across CFR tertiles, suggesting that inflammatory-disease specific risk factors may contribute to coronary vasomotor dysfunction.

Conclusions

In patients with systemic inflammatory disease, coronary vasomotor dysfunction was associated with worse outcomes independent of traditional CV risk factors and may have utility as a marker of CV risk among patients with inflammatory disease.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): 1. 5T32HL094301-02 NIH T32 Training Grant, “Noninvasive Cardiovascular Imaging Research Training Program”

Age-dependent cardiac remodelling – role of sex hormones

Background

While cardiovascular mortality in women has exceeded those in men, women continue to be underrepresented in cardiovascular clinical trials. Further, preclinical experiments are predominantly conducted in male animals, rendering sex-specific variables contributing to cardiovascular disease largely unknown. As age and menopause remain to be key risk factors for cardiovascular disease in women, the aim of this study was to identify key variables of cardiac remodelling in the aging female and male heart, as well as to assess effects of sex hormone deprivation on left ventricular (LV) morphology, LV function and cardiac sympathetic activity.

Materials and methods

Gonadectomized and sham-operated FVB/N mice of both sexes were subjected to positron emission tomography (PET) and cardiac magnetic resonance (CMR) imaging at the age of 4 (young cohort) and 20 (aged cohort) months (total n=123, 55% females). Following tail-vein injection of [11C]meta-hydroxynorephedrine ([11C]mHED), a widely used PET probe in preclinical and clinical assessment of cardiac sympathetic integrity, animals were scanned and cardiac sympathetic outflow was derived from myocardial [11C]mHED uptake. Cardiac parameters including LV volumes and left ventricular ejection fraction (LVEF) were obtained from electrocardiogram (ECG)-gated CMR imaging.

Results and discussion

A significant increase of LVEF was observed in aging females (p=0.012, Figure 1), but not in males. The latter was not associated with a higher cardiac output, and was a consequence of reduced LV end-systolic volumes (p=0.008), unveiling a substantial reduction of size in the aging female heart. As this age-dependent observation was not present in gonadectomized animals (p=0.414), the lack of growth-stimulating estrogen might account for reduction of cardiac size in aging females. Thus, despite a significantly heightened body weight, female heart size is reduced with age. Accordingly, sufficient cardiac output was maintained via increased heart rate (p=0.005) and cardiac sympathetic activity (p=0.040, Figure 1). Gonadectomy accelerated age-dependent changes in LV morphology and function in female mice. While sex hormone deprivation blunted cardiac sympathetic activity and norepinephrine levels in male mice, an opposite trend was observed in females.

Conclusion

Despite increasing body weight with age, aged female and male hearts maintain a stable circulatory blood supply, however, by distinct mechanisms. While the “shrinking” female heart requires an increased heart rate and cardiac sympathetic activity to compensate for smaller ventricular volumes, aging males maintain cardiac size. Importantly, sex hormone deprivation at a young age accelerates age-dependent changes in LV morphology and function in female mice, but not in male mice. The increased sympathetic activity reflects a higher stress level in aged females that might expose them to a higher cardiac vulnerability at postmenopausal age.

Funding Acknowledgement

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

Global trends in clinical trials involving pluripotent stem cells: a systematic multi-database analysis

Pluripotent stem cells (PSCs) hold great potential for novel therapeutic approaches to regenerate or replace functionally impaired tissues. Since the introduction of the induced pluripotent stem cell technology in 2006, the number of scientific publications on this topic has constantly been increasing. However, so far no therapy based on PSCs has found its way into routine clinical use. In this study, we examined research trends related to clinical trials involving PSCs based on data obtained from ClinicalTrials.gov, the ICTRP database from the World Health Organization, as well as from a search of all individual databases that are included in the ICTRP using a multistep search algorithm. Following a stringent inclusion/exclusion procedure 131 studies remained that could be classified as clinical trials involving PSCs. The magnitude of these studies (77.1%) was observational, which implies that no cells were transplanted into patients, and only a minority of studies (22.9%) were of an interventional study type. The number of clinical trials involving induced pluripotent stem cells (iPSCs, 74.8%) was substantially higher than the one involving embryonic stem cells (ESCs, 25.2%). However, the picture changes completely when focusing on interventional studies, where in the majority (73.3%) of cases ESCs were used. Interestingly, also the study duration was significantly shorter for interventional versus observational trials (p = 0.002). When focusing on the geographical study regions, it became obvious that the greatest part of all observational trials was performed in the USA (41.6%) and in France (16.8%), while the magnitude of interventional studies was performed in Asian countries (China 36.7%, Japan 13.3%, South Korea 10.0%) and in the field of ophthalmology. In summary, these results indicate that only a limited number of trials were focusing on the actual transplantation of PSCs into patients in a rather narrow field of diagnoses. The future will tell us, if the iPSC technology will ultimately overcome the current challenges and will finally make its way into routine clinical use.

Apremilast for extensive and treatment-resistant alopecia areata: a retrospective analysis of five patients

BACKGROUND

Recent experimental data suggest a role for apremilast in the treatment of alopecia areata. Small clinical studies have so far provided contradictory results.

OBJECTIVES

We retrospectively evaluated the efficacy and safety of apremilast in five cases of extensive and treatment-resistant alopecia areata.

MATERIALS AND METHODS

Apremilast was given at a dose of 30 mg, twice daily, over six months. The efficacy of apremilast treatment was determined by monthly assessment of the affected scalp surface area using SALT scoring.

RESULTS

In four out of five patients, no sustained improvement in SALT score was observed within the treatment period. Two of these patients had a slight but only transient improvement after two months of treatment. One patient responded to apremilast treatment with a progressive and marked improvement, as reflected by an 83% reduction in SALT score.

CONCLUSION

Our results are in line with the varying treatment responses in previous studies. Future studies on the efficacy of apremilast treatment in confirmed alopecia areata patient groups are warranted.

Fatal amyloid formation in a patient's antibody light chain is caused by a single point mutation

In systemic light chain amyloidosis, an overexpressed antibody light chain (LC) forms fibrils which deposit in organs and cause their failure. While it is well-established that mutations in the LC’s V_L domain are important prerequisites, the mechanisms which render a patient LC amyloidogenic are ill-defined. In this study, we performed an in-depth analysis of the factors and mutations responsible for the pathogenic transformation of a patient-derived λ LC, by recombinantly expressing variants in E. coli. We show that proteolytic cleavage of the patient LC resulting in an isolated V_L domain is essential for fibril formation. Out of 11 mutations in the patient V_L, only one, a leucine to valine mutation, is responsible for fibril formation. It disrupts a hydrophobic network rendering the C-terminal segment of V_L more dynamic and decreasing domain stability. Thus, the combination of proteolytic cleavage and the destabilizing mutation trigger conformational changes that turn the LC pathogenic.

Amyloid light chain amyloidosis, shortened to AL amyloidosis, is a rare and often fatal disease. It is caused by a disorder of the bone marrow. Usually, cells in the bone marrow produce Y-shaped proteins called antibodies to fight infections. In AL amyloidosis, these cells release too much of the short arm of the antibody, known as its light chain, and the light chains also carry mutations. The antibodies are no longer able to assemble properly, and instead misfold and form structures, known as amyloid fibrils. The fibrils build up outside the cells, gradually causing damage to tissues and organs that can lead to life-threatening organ failure.

Due to the rareness of the disease, diagnosis is often overlooked and delayed. People experience widely varying symptoms, depending on the organs affected. Also, given the diversity of antibodies people make, every person with AL amyloidosis has a variety of mutations implicated in their disease. It is thought that mutations in the antibody light chain make it unstable and prone to misfolding, but it remains unclear which specific mutations trigger a cascade of amyloid fibril formation.

Now, Kazman et al. have pinpointed the exact mechanism in one case of the disease. First, tissue biopsies from a woman with advanced AL amyloidosis were analyzed, and the defunct antibody light chain was isolated. Eleven mutations were identified in the antibody light chain, only one of which was found to be responsible for the formation of the harmful fibrils. The next step was to determine how this one small change was so damaging. The experiments showed that after the antibody light chain was cut in two, a process that happens naturally in the body, this single mutation transforms it into a protein capable of causing disease.

In this ‘bedside to lab bench’ study, Kazman et al. have succeeded in determining the molecular origin of one case of AL amyloidosis. The results have also shown that the instability of antibodies due to mutation does not alone explain the formation of amyloid fibrils in this disease and that the cutting of this protein in two is also important. It is hoped that, in the long run, this work will lead to new diagnostics and treatment options for people with AL amyloidosis.

Ageing of Polymer Frictional Interfaces: The Role of Quantity and Quality of Contact

When two objects are in contact, the force necessary for one to start sliding over the other is larger than the force necessary to keep the sliding motion going. This difference between static and dynamic friction is thought to result from a reduction in the area of real contact upon the onset of slip. Here, we resolve the structure in the area of contact on the molecular scale by means of environment-sensitive molecular rotors using (super-resolution) fluorescence microscopy and fluorescence lifetime imaging. We demonstrate that the macroscopic friction force is not only controlled by the area of real contact but also controlled by the "quality" of that area of real contact, which determines the friction per unit contact area. We show that the latter is affected by the local density of the contacting surfaces, a parameter that can be expected to change in time at any interface that involves glassy, amorphous materials.

Peptides in proteins

During evolution C-terminal peptide extensions were added to proteins on the gene level. These convey additional functions such as interaction with partner proteins or oligomerisation. IgM antibodies and molecular chaperones are two prominent examples discussed.

Volumetry of Mesiotemporal Structures Reflects Serostatus in Patients with Limbic Encephalitis

BACKGROUND AND PURPOSE

Limbic encephalitis is an autoimmune disease. A variety of autoantibodies have been associated with different subtypes of limbic encephalitis, whereas its MR imaging signature is uniformly characterized by mesiotemporal abnormalities across subtypes. Here, we hypothesized that patients with limbic encephalitis would show subtype-specific mesiotemporal structural correlates, which could be classified by supervised machine learning on an individual level.

MATERIALS AND METHODS

T1WI MPRAGE scans from 46 patients with antibodies against glutamic acid decarboxylase and 34 patients with antibodies against the voltage-gated potassium channel complex (including 10 patients with leucine-rich glioma-inactivated 1 autoantibodies) and 48 healthy controls were retrospectively ascertained. Parcellation of the amygdala, hippocampus, and hippocampal subfields was performed using FreeSurfer. Volumes were extracted and compared between groups using unpaired, 2-tailed t tests. The volumes of hippocampal subfields were analyzed using a multivariate linear model and a binary decision tree classifier.

RESULTS

Temporomesial volume alterations were most pronounced in an early stage and in the affected hemispheric side of patients. Statistical analysis revealed antibody-specific hippocampal fingerprints with a higher volume of CA1 in patients with glutamic acid decarboxylase-associated limbic encephalitis (P = .02), compared with controls, whereas CA1 did not differ from that in controls in patients with voltage-gated potassium channel complex autoantibodies. The classifier could successfully distinguish between patients with autoantibodies against leucine-rich glioma-inactivated 1 and glutamic acid decarboxylase with a specificity of 87% and a sensitivity of 80%.

CONCLUSIONS

Our results suggest stage-, side- and antibody-specific structural correlates of limbic encephalitis; thus, they create a perspective toward an MR imaging-based diagnosis.