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.

Clinical and immunological benefits of full primary COVID-19 vaccination in individuals with SARS-CoV-2 breakthrough infections: A prospective cohort study in non-hospitalized adults

BACKGROUND

SARS-CoV-2 variants of concern (VOC) may result in breakthrough infections (BTIs) in vaccinated individuals. The aim of this study was to investigate the effects of full primary (two-dose) COVID-19 vaccination with wild-type-based SARS-CoV-2 vaccines on symptoms and immunogenicity of SARS-CoV-2 VOC BTIs.

METHODS

In a longitudinal multicenter controlled cohort study in Bavaria, Germany, COVID-19 vaccinated and unvaccinated non-hospitalized individuals were prospectively enrolled within 14 days of a PCR-confirmed SARS-CoV-2 infection. Individuals were visited weekly up to 4 times, performing a structured record of medical data and viral load assessment. SARS-CoV-2-specific antibody response was characterized by anti-spike-(S)- and anti-nucleocapsid-(N)-antibody concentrations, anti-S-IgG avidity and neutralization capacity.

RESULTS

A total of 300 individuals (212 BTIs, 88 non-BTIs) were included with VOC Alpha or Delta SARS-CoV-2 infections. Full primary COVID-19 vaccination provided a significant effectiveness against five symptoms (relative risk reduction): fever (33 %), cough (21 %), dysgeusia (22 %), dizziness (52 %) and nausea/vomiting (48 %). Full primary vaccinated individuals showed significantly higher 50 % inhibitory concentration (IC50) values against the infecting VOC compared to unvaccinated individuals at week 1 (269 vs. 56, respectively), and weeks 5-7 (1,917 vs. 932, respectively) with significantly higher relative anti-S-IgG avidity (78% vs. 27 % at week 4, respectively).

CONCLUSIONS

Full primary COVID-19 vaccination reduced symptom frequencies in non-hospitalized individuals with BTIs and elicited a more rapid and longer lasting neutralization capacity against the infecting VOC compared to unvaccinated individuals. These results support the recommendation to offer at least full primary vaccination to all adults to reduce disease severity caused by immune escape-variants.

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.

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

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.

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

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.

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.

The frequency of photosensitizing drug dispensings in Austria and Germany: a correlation with their photosensitizing potential based on published literature

Background

Drug‐induced photosensitivity refers to the development of cutaneous adverse events due to interaction between a pharmaceutical compound and sunlight. Although photosensitivity is a very commonly listed side‐effect of systemic drugs, reliable data on its actual incidence are lacking so far.

Objectives

A possible approach to evaluate the real‐life extent of drug‐induced photosensitivity would be an analysis of the frequency of exposure to a given photosensitizing drug combined with an indicator of its photosensitizing potential. This could serve as a basis for developing a pharmaceutical ‘heatmap’ of photosensitivity.

Methods

The present study investigated the number of reimbursed dispensed packages of potentially photosensitizing drugs in Germany (DE) and Austria (AT) between 2010 and 2017 based on nationwide health insurance‐based databases. In addition, an indicator for the photosensitizing potential was established for each drug based on the number of reports on photosensitivity in the literature.

Results

This analysis includes means of 632 826 944 (+/−14 894 918) drug dispensings per year in DE and 113 270 754 (+/−1 964 690) in AT. Out of these, the mean percentage of drugs that enlist photosensitivity as a potential side‐effect was 49.5% (±0.7) in DE and 48.2% (±1.2) in AT. When plotting the number of reimbursed dispensed packages vs. the number of reports on photosensitivity, two categories of drugs show high numbers for both parameters, that is diuretics and non‐steroidal anti‐inflammatory drugs (NSAIDs).

Conclusions

Diuretics and NSAIDs appear to be responsible for the greatest part of exposure to photosensitizing drugs with potential implication on public health.

Serum levels of folate, 25-hydroxyvitamin D3 and cobalamin during UVB phototherapy: findings in a large prospective trial

Background

Narrowband UVB phototherapy (NB‐UVB) is a mainstay in the treatment of numerous inflammatory dermatoses. Whereas, a wealth of studies has shown that NB‐UVB treatment increases 25‐hydroxyvitamin D3 (25(OH)D) levels, only sparse and controversial data exist on its effect on serum folate and cobalamin.

Objectives

To determine whether exposure to NB‐UVB alters serum folate or cobalamin levels.

Methods

A single‐centre, prospective, open observational study on 101 patients subjected to NB‐UVB phototherapy between late fall and early spring. Serum folate, 25(OH)D and cobalamin levels were measured after 0, 12, 24 and 36 NB‐UVB exposures.

Results

After 12 NB‐UVB exposures a significant decrease of mean serum folate (−1.0 nmol/L; P = 0.03) and cobalamin (−14.5 pmol/L, P = 0.03) levels was observed whereas serum levels of 25(OH)D showed a significant increase (35.4 nmol/L, P < 0.0001).

Conclusions

A standard course of NB‐UVB induces a small but significant decrease of serum folate and cobalamin levels.

Frictional weakening of slip interfaces

When two objects are in contact, the force necessary to overcome friction is larger than the force necessary to keep sliding motion going. This difference between static and dynamic friction is usually attributed to the growth of the area of real contact between rough surfaces in time when the system is at rest. We directly measure the area of real contact and show that it actually increases during macroscopic slip, despite the fact that dynamic friction is smaller than static friction. This signals a decrease in the interfacial shear strength, the friction per unit contact area, which is due to a mechanical weakening of the asperities. This provides a novel explanation for stick-slip phenomena in, e.g., earthquakes.

The relationship between "Eyes Reading" ability and verbal memory in bipolar disorder

In psychiatric disorders, neurocognitive impairments are prevalent and have been associated with poor outcome. Deficits in Theory of Mind (ToM, "mentalising") have also been observed in bipolar disorder (BD); however, the literature shows inconsistent data. The aim of this study was to explore ToM performance in a well-characterized sample of euthymic individuals with BD and its relationship with neurocognitive function. One hundred sixteen euthymic patients with BD between 18 and 74 years (mean age = 42.4, SD = 13.8) and 79 healthy controls (mean age = 39.8, SD = 16.5) were investigated with an extensive neurocognitive test battery (Trail Making Test A/B, d2 Test of Attention, Stroop Color-Word Test, California Verbal Learning Test, Multiple Choice Vocabulary Test). Additionally, all participants were given the Reading the Mind in the Eyes Test (RMET) to measure affective ToM, the ability to make assumptions about other people´s feelings. Overall, "Eyes Reading" performance was not impaired in individuals with BD compared with controls. However, a significant relationship between RMET and verbal memory in BD was shown, particularly in males. Data showed worse RMET performance in patients with memory deficits compared to patients without memory deficits and controls. Due to cross-sectional data, no conclusions can be made with respect to cause and effect.

Hippocampal subfield segmentation in temporal lobe epilepsy: Relation to outcomes

Objective

To investigate the clinical and surgical outcome correlates of preoperative hippocampal subfield volumes in patients with refractory temporal lobe epilepsy (TLE) using a new magnetic resonance imaging (MRI) multisequence segmentation technique.

Methods

We recruited 106 patients with TLE and hippocampal sclerosis (HS) who underwent conventional T1‐weighted and T2 short TI inversion recovery MRI. An automated hippocampal segmentation algorithm was used to identify twelve subfields in each hippocampus. A total of 76 patients underwent amygdalohippocampectomy and postoperative seizure outcome assessment using the standardized ILAE classification. Semiquantitative hippocampal internal architecture (HIA) ratings were correlated with hippocampal subfield volumes.

Results

Patients with left TLE had smaller volumes of the contralateral presubiculum and hippocampus‐amygdala transition area compared to those with right TLE. Patients with right TLE had reduced contralateral hippocampal tail volumes and improved outcomes. In all patients, there were no significant relationships between hippocampal subfield volumes and clinical variables such as duration and age at onset of epilepsy. There were no significant differences in any hippocampal subfield volumes between patients who were rendered seizure free and those with persistent postoperative seizure symptoms. Ipsilateral but not contralateral HIA ratings were significantly correlated with gross hippocampal and subfield volumes.

Conclusions

Our results suggest that ipsilateral hippocampal subfield volumes are not related to the chronicity/severity of TLE. We did not find any hippocampal subfield volume or HIA rating differences in patients with optimal and unfavorable outcomes. In patients with TLE and HS, sophisticated analysis of hippocampal architecture on MRI may have limited value for prediction of postoperative outcome.

Molecular probes reveal deviations from Amontons' law in multi-asperity frictional contacts

Amontons’ law defines the friction coefficient as the ratio between friction force and normal force, and assumes that both these forces depend linearly on the real contact area between the two sliding surfaces. However, experimental testing of frictional contact models has proven difficult, because few in situ experiments are able to resolve this real contact area. Here, we present a contact detection method with molecular-level sensitivity. We find that while the friction force is proportional to the real contact area, the real contact area does not increase linearly with normal force. Contact simulations show that this is due to both elastic interactions between asperities on the surface and contact plasticity of the asperities. We reproduce the contact area and fine details of the measured contact geometry by including plastic hardening into the simulations. These new insights will pave the way for a quantitative microscopic understanding of contact mechanics and tribology.

Amontons’ law assumes that friction and normal forces depend linearly on the contact area. Here, the authors use a new contact detection method to show that the law is broken because asperities interact and deform in the contact area to change it, thereby also changing the friction force.

Effects of ketamine on brain function during smooth pursuit eye movements

The uncompetitive NMDA receptor antagonist ketamine has been proposed to model symptoms of psychosis. Smooth pursuit eye movements (SPEM) are an established biomarker of schizophrenia. SPEM performance has been shown to be impaired in the schizophrenia spectrum and during ketamine administration in healthy volunteers. However, the neural mechanisms mediating SPEM impairments during ketamine administration are unknown. In a counter-balanced, placebo-controlled, double-blind, within-subjects design, 27 healthy participants received intravenous racemic ketamine (100 ng/mL target plasma concentration) on one of two assessment days and placebo (intravenous saline) on the other. Participants performed a block-design SPEM task during functional magnetic resonance imaging (fMRI) at 3 Tesla field strength. Self-ratings of psychosis-like experiences were obtained using the Psychotomimetic States Inventory (PSI). Ketamine administration induced psychosis-like symptoms, during ketamine infusion, participants showed increased ratings on the PSI dimensions cognitive disorganization, delusional thinking, perceptual distortion and mania. Ketamine led to robust deficits in SPEM performance, which were accompanied by reduced blood oxygen level dependent (BOLD) signal in the SPEM network including primary visual cortex, area V5 and the right frontal eye field (FEF), compared to placebo. A measure of connectivity with V5 and FEF as seed regions, however, was not significantly affected by ketamine. These results are similar to the deviations found in schizophrenia patients. Our findings support the role of glutamate dysfunction in impaired smooth pursuit performance and the use of ketamine as a pharmacological model of psychosis, especially when combined with oculomotor biomarkers. Hum Brain Mapp 37:4047-4060, 2016. © 2016 Wiley Periodicals, Inc.

Cardiac Depression in Pigs after Multiple Trauma - Characterization of Posttraumatic Structural and Functional Alterations

The purpose of this study was to define the relationship between cardiac depression and morphological and immunological alterations in cardiac tissue after multiple trauma. However, the mechanistic basis of depressed cardiac function after trauma is still elusive. In a porcine polytrauma model including blunt chest trauma, liver laceration, femur fracture and haemorrhage serial trans-thoracic echocardiography was performed and correlated with cellular cardiac injury as well as with the occurrence of extracellular histones in serum. Postmortem analysis of heart tissue was performed 72 h after trauma. Ejection fraction and shortening fraction of the left ventricle were significantly impaired between 4 and 27 h after trauma. H-FABP, troponin I and extracellular histones were elevated early after trauma and returned to baseline after 24 and 48 h, respectively. Furthermore, increased nitrotyrosine and Il-1β generation and apoptosis were identified in cardiac tissue after trauma. Main structural findings revealed alteration of connexin 43 (Cx43) and co-translocation of Cx43 and zonula occludens 1 to the cytosol, reduction of α-actinin and increase of desmin in cardiomyocytes after trauma. The cellular and subcellular events demonstrated in this report may for the first time explain molecular mechanisms associated with cardiac dysfunction after multiple trauma.

Sixteen novel mutations in PNPLA1 in patients with autosomal recessive congenital ichthyosis reveal the importance of an extended patatin domain in PNPLA1 that is essential for proper human skin barrier function

BACKGROUND

Autosomal recessive congenital ichthyosis (ARCI) is a genetically heterogeneous group of rare Mendelian skin disorders characterized by cornification and differentiation defects of keratinocytes. Mutations in nine genes including PNPLA1 are known to cause nonsyndromic forms of ARCI. To date, only 10 distinct pathogenic mutations in PNPLA1 have been reported.

OBJECTIVES

To identify new causative PNPLA1 mutations.

METHODS

We screened genetically unresolved cases, including our ARCI collection, comprising more than 700 families. Screening for mutations was performed either by direct Sanger sequencing or in combination with a multigene panel, followed by sequence and mutation analysis.

RESULTS

Here we report on 16 novel mutations present in patients from 17 families. While all previously reported mutations and most of our novel mutations are located within the core patatin domain, we report five novel PNPLA1 mutations that are downstream of this domain. Thus, as recently described for PNPLA2, we hypothesize that a region larger than the core domain is required for full enzymatic activity of PNPLA1 in human skin barrier formation.

CONCLUSIONS

We estimate the frequency of PNPLA1 mutations among patients with ARCI to be around 3%. Most of our patients were born as collodion babies and showed a relatively mild ichthyosis phenotype. In four unrelated patients we observed a cyclic scaling course, which seems to be a potential phenotypic variation in a small percentage of patients with PNPLA1 mutations. The variability of the clinical manifestations and the lack of typical clinical features are specific for patients with PNPLA1 mutations, and emphasize the importance of DNA sequencing for differential diagnosis of ARCIs.

Model Evaluation of Continuous Data Pharmacometric Models: Metrics and Graphics

This article represents the first in a series of tutorials on model evaluation in nonlinear mixed effect models (NLMEMs), from the International Society of Pharmacometrics (ISoP) Model Evaluation Group. Numerous tools are available for evaluation of NLMEM, with a particular emphasis on visual assessment. This first basic tutorial focuses on presenting graphical evaluation tools of NLMEM for continuous data. It illustrates graphs for correct or misspecified models, discusses their pros and cons, and recalls the definition of metrics used.

Validation of ELISA methods for quantification of the major birch allergen Bet v 1 (BSP090)

To date, the potency of allergen products in Europe is expressed in manufacturer-specific units relative to a product-specific in-house reference. Consequently, cross-product comparability of allergen products from different manufacturers with respect to strength and efficacy is impossible. The Biological Standardisation Programme (BSP) project BSP090 addresses this issue via the establishment of reference standards in conjunction with ELISA methods for the quantification of major allergens in allergen products. Since the initiation of BSP090, the recombinant major allergen Bet v 1 has been adopted by the European Pharmacopoeia Commission as a Chemical Reference Substance (CRS). In parallel, two sandwich ELISA systems for quantification of Bet v 1 were found suitable in preliminary phases of BSP090 to be validated in a large collaborative study. In this study, the candidate ELISA systems were compared with respect to accuracy, precision and variability. Thirteen participating laboratories tested model samples containing the CRS as well as spiked and unspiked birch pollen extracts. Both in pre-testing and in the collaborative study, the 2 candidate ELISA systems confirmed their suitability to quantify recombinant and native Bet v 1. As no clear-cut decision for one of the ELISA systems could be made based on the results of the collaborative study, a post-study testing was performed. Bet v 1 content of 30 birch pollen allergen products was determined in parallel in both ELISA systems. Consequently, 1 candidate ELISA system was selected to be proposed as the future European Pharmacopoeia standard method for Bet v 1 quantification.