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1.
Learn Mem ; 31(4)2024 Apr.
Article in English | MEDLINE | ID: mdl-38740426

ABSTRACT

Emotional stimuli are usually remembered with high confidence. Yet, it remains unknown whether-in addition to memory for the emotional stimulus itself-memory for a neutral stimulus encountered just after an emotional one can be enhanced. Further, little is known about the interplay between emotion elicited by a stimulus and emotion relating to affective dispositions. To address these questions, we examined (1) how emotional valence and arousal of a context image preceding a neutral item image affect memory of the item, and (2) how such memory modulation is affected by two hallmark features of emotional disorders: trait negative affect and tendency to worry. In two experiments, participants encoded a series of trials in which an emotional (negative, neutral, or positive) context image was followed by a neutral item image. In experiment 1 (n = 42), items presented seconds after negative context images were remembered better and with greater confidence compared to those presented after neutral and positive ones. Arousal ratings of negative context images were higher compared to neutral and positive ones and the likelihood of correctly recognizing an item image was related to higher arousal of the context image. In experiment 2 (n = 59), better item memory was related to lower trait negative affect. Participants with lower trait negative affect or tendency to worry displayed higher confidence compared to those with high negative affect or tendency to worry. Our findings describe an emotional "carry-over" effect elicited by a context image that enhances subsequent item memory on a trial-by-trial basis, however, not in individuals with high trait negative affect who seem to have a general memory disadvantage.


Subject(s)
Anxiety , Emotions , Humans , Female , Male , Young Adult , Emotions/physiology , Adult , Affect/physiology , Arousal/physiology , Adolescent , Memory/physiology
2.
Chemistry ; 30(10): e202303007, 2024 Feb 16.
Article in English | MEDLINE | ID: mdl-38100216

ABSTRACT

Extracellular amyloid-ß (Aß) plaques, primarily formed by Aß(1-40) and Aß(1-42) fibrils, are a hallmark of Alzheimer's disease. The Aß peptide can undergo a high variety of different post-translational modifications including formation of a pyroglutamate (pGlu, pE) at N-terminal Glu3 or Glu11 of truncated Aß(3-x) or Aß(11-x), respectively. Here we studied structural similarities and differences between pEAß(3-42) and LS-shaped Aß(1-42) fibrils grown under identical conditions (pH 2) using solid-state NMR spectroscopy. We show that the central region of pEAß(3-42) fibrils including the turn region around V24 is almost identical to Aß(1-42) showing similar ß-strands also at the N-terminus. The missing N-terminal residues D1-A2 along with pE3 formation in pEAß(3-42) preclude a salt bridge between K28-D1' as in Aß(1-42) fibrils. G37 and G38 act as highly sensitive internal sensors for the modified N-terminus, which remains rigid over ~five pH units.


Subject(s)
Alzheimer Disease , Pyrrolidonecarboxylic Acid , Humans , Pyrrolidonecarboxylic Acid/chemistry , Amyloid beta-Peptides/chemistry , Magnetic Resonance Spectroscopy , Peptide Fragments/chemistry
3.
Front Mol Biosci ; 10: 1254721, 2023.
Article in English | MEDLINE | ID: mdl-38046811

ABSTRACT

Introduction: Misfolding of amyloidogenic proteins is a molecular hallmark of neurodegenerative diseases in humans. A detailed understanding of the underlying molecular mechanisms is mandatory for developing innovative therapeutic approaches. The bovine PI3K-SH3 domain has been a model system for aggregation and fibril formation. Methods: We monitored the fibril formation kinetics of low pH-denatured recombinantly expressed [U-13C, 15N] labeled bovine PI3K-SH3 by a combination of solution NMR, high-resolution magic angle spinning (HR-MAS) NMR and solid-state NMR spectra. Solution NMR offers the highest sensitivity and, therefore, allows for the recording of two-dimensional NMR spectra with residue-specific resolution for individual time points of the time series. However, it can only follow the decay of the aggregating monomeric species. In solution NMR, aggregation occurs under quiescent experimental conditions. Solid-state NMR has lower sensitivity and allows only for the recording of one-dimensional spectra during the time series. Conversely, solid-state NMR is the only technique to detect disappearing monomers and aggregated species in the same sample by alternatingly recoding scalar coupling and dipolar coupling (CP)-based spectra. HR-MAS NMR is used here as a hybrid method bridging solution and solid-state NMR. In solid-state NMR and HR-MAS NMR the sample is agitated due to magic angle spinning. Results: Good agreement of the decay rate constants of monomeric SH3, measured by the three different NMR methods, is observed. Moderate MAS up to 8 kHz seems to influence the aggregation kinetics of seeded fibril formation only slightly. Therefore, under sufficient seeding (1% seeds used here), quiescent conditions (solution NMR), and agitated conditions deliver similar results, arguing against primary nucleation induced by MAS as a major contributor. Using solid-state NMR, we find that the amount of disappeared monomer corresponds approximately to the amount of aggregated species under the applied experimental conditions (250 µM PI3K-SH3, pH 2.5, 298 K, 1% seeds) and within the experimental error range. Data can be fitted by simple mono-exponential conversion kinetics, with lifetimes τ in the 14-38 h range. Atomic force microscopy confirms that fibrils substantially grew in length during the aggregation experiment. This argues for fibril elongation as the dominant growth mechanism in fibril mass (followed by the CP-based solid-state NMR signal). Conclusion: We suggest a combined approach employing both solution NMR and solid-state NMR, back-to-back, on two aliquots of the same sample under seeding conditions as an additional approach to follow monomer depletion and growth of fibril mass simultaneously. Atomic force microscopy images confirm fibril elongation as a major contributor to the increase in fibril mass.

4.
J Am Chem Soc ; 145(4): 2161-2169, 2023 02 01.
Article in English | MEDLINE | ID: mdl-36653015

ABSTRACT

Alzheimer's disease is a neurodegenerative disorder associated with the deposition of misfolded aggregates of the amyloid-ß protein (Aß). Aß(1-42) is one of the most aggregation-prone components in senile plaques of AD patients. We demonstrated that relatively homogeneous Aß(1-42) fibrils with one predominant fold visible in solid-state NMR spectra can be obtained at acidic pH. The structure of these fibrils differs remarkably from some other polymorphs obtained at neutral pH. In particular, the entire N-terminal region is part of the rigid fibril core. Here, we investigate the effects of a pH shift on the stability and the fold of these fibrils at higher pH values. Fibril bundling at neutral pH values renders cryo-EM studies impractical, but solid-state NMR spectroscopy, molecular dynamics simulations, and biophysical methods provide residue-specific structural information under these conditions. The LS-fold of the Aß(1-42) fibrils does not change over the complete pH range from pH 2 to pH 7; in particular, the N-terminus remains part of the fibril core. We observe changes in the protonation state of charged residues starting from pH 5 on a residue-specific level. The deprotonation of the C-terminal carboxyl group of A42 in the intermolecular salt bridge with D1 and K28 is slow on the NMR time scale, with a local pKa of 5.4, and local conformations of the involved residues are affected by deprotonation of A42. Thus, we demonstrate that this fibril form is stable at physiological pH values.


Subject(s)
Alzheimer Disease , Amyloid , Humans , Amyloid/chemistry , Amyloid beta-Peptides/chemistry , Alzheimer Disease/metabolism , Peptide Fragments/chemistry , Hydrogen-Ion Concentration
5.
Pathol Res Pract ; 238: 154126, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36137398

ABSTRACT

BACKGROUND & AIMS: In recent years, histopathological characterization of intrahepatic cholangiocarcinoma revealed small duct type (SD-iCCA) and large duct type (LD-iCCA). Data on the prevalence of the subtypes are limited and highly varying. The aim of this study was to assess the prevalence of SD-iCCA and LD-iCCA and their impact on survival for the first time in a European cohort. MATERIALS AND METHODS: All patients with surgically resected iCCA diagnosed between December 2005 and December 2021 at the University Hospital Frankfurt were analyzed by an expert hepatobiliary pathologist. For overall survival (OS) and progression-free survival (PFS), Kaplan-Meier curves and Cox-regression analyses were performed. RESULTS: In total, 116 patients with surgically resected iCCA treated in our tertiary hospital were classified as SD-iCCA (73.3%, n = 85) and LD-iCCA (26.7%, n = 31). Subgroup analyses revealed median OS of 54.4 months (95% CI = 38.3 - 70.4 months) and 25.4 months (95% CI = 15.1 - 35.7 months) for SD-iCCA and LD-iCCA, respectively (p = 0.027). The median PFS for patients receiving gemcitabine-based chemotherapy with SD- and LD-iCCA was 8.4 months (95% CI = 4.7 - 12 months) and 3.3 months (95% CI = 1.8 - 4.7 months), respectively (p = 0.011). While LD-iCCA was as a significant risk factor of OS (HR = 1.7, 95% CI = 1 - 2.8, p = 0.031) in univariate analysis, it was not significant in multivariate analysis. CONCLUSION: In contrast to data from Asia, SD-iCCA is more prevalent than LD-iCCA in our cohort. LD-iCCA is associated with impaired OS after surgical resection and decreased PFS for patients receiving chemotherapy. These findings may suggest including the histological subtype in clinical routine diagnostics.

6.
Behav Res Ther ; 157: 104161, 2022 10.
Article in English | MEDLINE | ID: mdl-35932550

ABSTRACT

Although Pavlovian threat conditioning has proven to be a useful translational model for the development of anxiety disorders, it remains unknown if this procedure can generate intrusive memories - a symptom of many anxiety-related disorders, and whether intrusions persist over time. Social support has been related to better adjustment after trauma however, experimental evidence regarding its effect on the development of anxiety-related symptoms is sparse. We had two aims: to test whether threat conditioning generates intrusive memories, and whether different social support interactions impacted expression of emotional memories. Non-clinical participants (n = 81) underwent threat conditioning to neutral stimuli. Participants were then assigned to a supportive, unsupportive, or no social interaction group, and asked to report intrusive memories for seven days. As predicted, threat conditioning can generate intrusions, with greater number of intrusions of CS+ (M = 2.35, SD = 3.09) than CS- (M = 1.39, SD = 2.17). Contrary to predictions, compared to no social interaction, supportive social interaction did not reduce, and unsupportive interaction did not increase skin conductance of learned threat or number of intrusions. Unsupportive interaction resulted in a relative difference in number of intrusions to CS + vs CS-, suggesting that unsupportive interaction might have increased image-based threat memories. Intrusions were still measurable one year after conditioning (one-year follow-up; n = 54), when individuals with higher trait anxiety and greater number of previous trauma experiences reported more intrusions. Our findings show that threat conditioning can create long-lasting intrusions, offering a novel experimental psychopathology model of intrusive memories with implications for both research on learning and clinical applications.


Subject(s)
Conditioning, Classical , Stress Disorders, Post-Traumatic , Anxiety/psychology , Emotions , Humans , Stress Disorders, Post-Traumatic/psychology
7.
Front Med (Lausanne) ; 9: 875142, 2022.
Article in English | MEDLINE | ID: mdl-35783619

ABSTRACT

Introduction and Objective: Identifying patients that benefit from cisplatin-based adjuvant chemotherapy is a major issue in the management of muscle-invasive bladder cancer (MIBC). The purpose of this study is to correlate "luminal" and "basal" type protein expression with histological subtypes, to investigate the prognostic impact on survival after adjuvant chemotherapy and to define molecular consensus subtypes of "double negative" patients (i.e., without expression of CK5/6 or GATA3). Materials and Methods: We performed immunohistochemical (IHC) analysis of CK5/6 and GATA3 for surrogate molecular subtyping in 181 MIBC samples. The mRNA expression profiles for molecular consensus classification were determined in CK5/6 and GATA3 (double) negative cases using a transcriptome panel with 19.398 mRNA targets (HTG Molecular Diagnostics). Data of 110 patients undergoing radical cystectomy were available for survival analysis. Results: The expression of CK5/6 correlated with squamous histological subtype (96%) and expression of GATA3 was associated with micropapillary histology (100%). In the multivariate Cox-regression model, patients receiving adjuvant chemotherapy had a significant survival benefit (hazard ratio [HR]: 0.19 95% confidence interval [CI]: 0.1-0.4, p < 0.001) and double-negative cases had decreased OS (HR: 4.07; 95% CI: 1.5-10.9, p = 0.005). Double negative cases were classified as NE-like (30%), stroma-rich (30%), and Ba/Sq (40%) consensus molecular subtypes and displaying different histological subtypes. Conclusion: Immunohistochemical-based classification was associated with histological subtypes of urothelial MIBC. IHC markers like CK5/6 and GATA3 that are used in pathological routine could help to identify patients with basal and luminal tumor characteristics. However, a two-sided classification system might not sufficiently reflect the heterogeneity of bladder cancer to make treatment decisions. Especially the group of IHC-double negative cases, as further analyzed by mRNA expression profiling, are a heterogeneous group with different implications for therapy.

8.
Front Neurol ; 13: 766685, 2022.
Article in English | MEDLINE | ID: mdl-35309564

ABSTRACT

Background: Acute dizziness, vertigo, and imbalance are frequent and difficult to interpret symptoms in the emergency department (ED). Primary care hospitals often lack the expertise to identify stroke or TIA as underlying causes. A telemedical approach based on telestroke networks may offer adequate diagnostics and treatment. Aim: The aim of this study is to evaluate the accuracy of a novel ED algorithm in differentiating between peripheral and central vestibular causes. Methods: Within the Telemedical Project for Integrative Stroke Care (TEMPiS), a telemedical application including a videooculography (VOG) system was introduced in 2018 in 19 primary care spoke hospitals. An ED triage algorithm was established for all patients with acute dizziness, vertigo, or imbalance of unknown cause (ADVIUC) as a leading complaint. In three predefined months, all ADVIUC cases were prospectively registered and discharge letters analyzed. Accuracy of the ED triage algorithm in differentiation between central and peripheral vestibular cases was analyzed by comparison of ED diagnoses to final discharge diagnoses. The rate of missed strokes was calculated in relation to all cases with a suitable brain imaging. Acceptance of teleconsultants and physicians in spoke hospitals was assessed by surveys. Results: A total number of 388 ADVIUC cases were collected, with a median of 12 cases per months and hospital (IQR 8-14.5). The most frequent hospital discharge diagnoses are vestibular neuritis (22%), stroke/TIA (18%), benign paroxysmal positioning vertigo (18%), and dizziness due to internal medicine causes (15%). Detection of a central vestibular cause by the ED triage algorithm has a high sensitivity (98.6%), albeit poor specificity (45.9%). One stroke out of 32 verified by brain scan was missed (3.1%). User satisfaction, helpfulness of the project, improvement of care, personal competence, and satisfaction about handling of the VOG systems were rated consistently positive. Discussion: The concept shows good acceptance for a telemedical and network-based approach to manage ADVIUC cases in the ED of primary care hospitals. Identification of stroke cases is accurate, while specificity needs further improvement. The concept could be a major step toward a broadly available state of the art diagnostics and therapy for patients with ADVIUC in primary care hospitals.

9.
Cell Death Discov ; 8(1): 11, 2022 Jan 10.
Article in English | MEDLINE | ID: mdl-35013156

ABSTRACT

The induction of apoptosis is a direct way to eliminate tumor cells and improve cancer therapy. Apoptosis is tightly controlled by the balance of pro- and antiapoptotic Bcl-2 proteins. BH3 mimetics neutralize the antiapoptotic function of Bcl-2 proteins and are highly promising compounds inducing apoptosis in several cancer entities including pediatric malignancies. However, the clinical application of BH3 mimetics in solid tumors is impeded by the frequent resistance to single BH3 mimetics and the anticipated toxicity of high concentrations or combination treatments. One potential avenue to increase the potency of BH3 mimetics is the development of immune cell-based therapies to counteract the intrinsic apoptosis resistance of tumor cells and sensitize them to immune attack. Here, we describe spheroid cultures of pediatric cancer cells that can serve as models for drug testing. In these 3D models, we were able to demonstrate that activated allogeneic Natural Killer (NK) cells migrated into tumor spheroids and displayed cytotoxicity against a wide range of pediatric cancer spheroids, highlighting their potential as anti-tumor effector cells. Next, we investigated whether treatment of tumor spheroids with subtoxic concentrations of BH3 mimetics can increase the cytotoxicity of NK cells. Notably, the cytotoxic effects of NK cells were enhanced by the addition of BH3 mimetics. Treatment with either the Bcl-XL inhibitor A1331852 or the Mcl-1 inhibitor S63845 increased the cytotoxicity of NK cells and reduced spheroid size, while the Bcl-2 inhibitor ABT-199 had no effect on NK cell-mediated killing. Taken together, this is the first study to describe the combination of BH3 mimetics targeting Bcl-XL or Mcl-1 with NK cell-based immunotherapy, highlighting the potential of BH3 mimetics in immunotherapy.

10.
Transl Psychiatry ; 11(1): 639, 2021 12 17.
Article in English | MEDLINE | ID: mdl-34921141

ABSTRACT

Chronic mental illnesses (CMIs) pose a significant challenge to global health due to their complex and poorly understood etiologies and hence, absence of causal therapies. Research of the past two decades has revealed dysfunction of the disrupted in schizophrenia 1 (DISC1) protein as a predisposing factor involved in several psychiatric disorders. DISC1 is a multifaceted protein that serves myriads of functions in mammalian cells, for instance, influencing neuronal development and synapse maintenance. It serves as a scaffold hub forming complexes with a variety (~300) of partners that constitute its interactome. Herein, using combinations of structural and biophysical tools, we demonstrate that the C-region of the DISC1 protein is highly polymorphic, with important consequences for its physiological role. Results from solid-state NMR spectroscopy and electron microscopy indicate that the protein not only forms symmetric oligomers but also gives rise to fibrils closely resembling those found in certain established amyloid proteinopathies. Furthermore, its aggregation as studied by isothermal titration calorimetry (ITC) is an exergonic process, involving a negative enthalpy change that drives the formation of oligomeric (presumably tetrameric) species as well as ß-fibrils. We have been able to narrow down the ß-core region participating in fibrillization to residues 716-761 of full-length human DISC1. This region is absent in the DISC1Δ22aa splice variant, resulting in reduced association with proteins from the dynein motor complex, viz., NDE-like 1 (NDEL1) and lissencephaly 1 (LIS1), which are crucial during mitosis. By employing surface plasmon resonance, we show that the oligomeric DISC1 C-region has an increased affinity and shows cooperativity in binding to LIS1 and NDEL1, in contrast to the noncooperative binding mode exhibited by the monomeric version. Based on the derived structural models, we propose that the association between the binding partners involves two neighboring subunits of DISC1 C-region oligomers. Altogether, our findings highlight the significance of the DISC1 C-region as a crucial factor governing the balance between its physiological role as a multifunctional scaffold protein and aggregation-related aberrations with potential significance for disease.


Subject(s)
Mental Disorders , Nerve Tissue Proteins , Animals , Carrier Proteins , Humans , Microtubule-Associated Proteins , Nerve Tissue Proteins/metabolism , Synapses/metabolism
11.
R Soc Open Sci ; 8(11): 202116, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34849237

ABSTRACT

Past research has shown that attributions of intentions to other's actions determine how we experience these actions and their consequences. Yet, it is unknown how such attributions affect our learning and memory. Addressing this question, we combined neuroimaging with an interactive threat learning paradigm in which two interaction partners (confederates) made choices that had either threatening (shock) or safe (no shock) consequences for the participants. Importantly, participants were led to believe that one partner intentionally caused the delivery of shock, whereas the other did not (i.e. unintentional partner). Following intentional versus unintentional shocks, participants reported an inflated number of shocks and a greater increase in anger and vengeance. We applied a model-based representational similarity analysis to blood-oxygen-level-dependent (BOLD)-MRI patterns during learning. Surprisingly, we did not find any effects of intentionality. The threat value of actions, however, was represented as a trial-by-trial increase in representational similarity in the insula and the inferior frontal gyrus. Our findings illustrate how neural pattern formation can be used to study a complex interaction.

13.
Neuroimage ; 201: 116020, 2019 11 01.
Article in English | MEDLINE | ID: mdl-31323259

ABSTRACT

Functional magnetic resonance imaging (MRI) studies have demonstrated a critical role of hippocampus and inferior frontal gyrus (IFG) in associative memory. Similarly, evidence from structural MRI studies suggests a relationship between gray-matter volume in these regions and associative memory. However, how brain volume and activity relate to each other during associative-memory formation remains unclear. Here, we used joint independent component analysis (jICA) to examine how gray-matter volume and brain activity would be associated during associative encoding, especially in medial-temporal lobe (MTL) and IFG. T1-weighted images were collected from 27 young adults, and functional MRI was employed during intentional encoding of object pairs. A subsequent recognition task tested participants' memory performance. Unimodal analyses using voxel-based morphometry revealed that participants with better associative memory showed larger gray-matter volume in left anterior hippocampus. Results from the jICA revealed one component that comprised a covariance pattern between gray-matter volume in anterior and posterior MTL and encoding-related activity in IFG. Our findings suggest that gray matter within the MTL modulates distally distinct parts of the associative encoding circuit, and extend previous studies that demonstrated MTL-IFG functional connectivity during associative memory tasks.


Subject(s)
Gray Matter/anatomy & histology , Gray Matter/physiology , Magnetic Resonance Imaging , Prefrontal Cortex/anatomy & histology , Prefrontal Cortex/physiology , Temporal Lobe/anatomy & histology , Temporal Lobe/physiology , Adult , Association , Female , Humans , Male , Memory , Organ Size , Temporal Lobe/diagnostic imaging , Young Adult
14.
Mamm Biol ; 94(1): 120-126, 2019.
Article in English | MEDLINE | ID: mdl-32218715

ABSTRACT

Studies of immunity in bat species are rare. However, it is important to determine immunological variations to identify factors influencing the health status of these endangered mammals from an evolutionary, ecological, conservation, and public health point of view. Immunity is highly variable and can be influenced by both internal (e.g. hormone levels, energy demand) and external factors (e.g. pathogens, climate). As bats have some peculiar ecological, energetic, and putative immunological characteristics, they are outstanding study organisms for ecoimmunological studies. We tested if (i) female bats have a higher immunity than males similar to most other mammalian species and (ii) individuals differ according to their energy demand (e.g. reproductive status). To study these questions, we sampled female and male Myotis daubentonii with different reproductive states and estimated their bacterial killing activity, hemolysis/hemagglutination titer, immunoglobulin G (IgG) concentration, and total and differential white blood cell counts. These methods characterize the cellular and humoral branches of both the adaptive and the innate immune responses of these individuals. Reproductively active males had lower cellular immunity compared to non-reproductive individuals. Pregnant females had increased IgG concentrations while hemolysis was enhanced during lactation. No clear trade-off between immunity and reproduction was found; instead immunity of males and female bats seems to be modulated differently due to varying hormonal and energetic states. Our data suggest that both adaptive and innate immunity as well as individual differences (i.e. sex and reproductive state) need to be considered to get a comprehensive overall picture of immunity in wild mammals.

15.
Environ Sci Pollut Res Int ; 25(6): 5437-5446, 2018 Feb.
Article in English | MEDLINE | ID: mdl-29214475

ABSTRACT

Recently, a number of studies demonstrated the suitability of hair analysis to assess metal exposure of bats. As many bat species are endangered, such a non-destructive method is particularly suited for this taxon. The present study analyzed the levels of two non-essential (cadmium and lead) and four essential metals (copper, manganese, molybdenum, and zinc) in hairs of three ecologically similar, sympatric bat species, Bechstein's bat (Myotis bechsteinii), Natterer's bat (Myotis nattereri), and Brown long-eared bat (Plecotus auritus) from an area in Central Hesse (Germany), as well as metal concentrations in soil samples from the bats' foraging habitats. Applying a previously established protocol, the analyses were performed using microwave-assisted extraction followed by inductively coupled plasma optical emission spectrometry. Cadmium and lead concentrations in hair did not differ significantly among the three studied species, whereas the following significant differences existed for levels of essential metals in hair. Manganese concentrations in hair were higher in M. bechsteinii and P. auritus than in M. nattereri and Cu concentrations were higher in M. nattereri than in P. auritus. Myotis bechsteinii showed higher Zn concentrations compared to P. auritus and lower Mo concentrations compared to M. nattereri. Reasons for the observed differences among the three studied species could be differential exposure to these metal elements in their foraging areas, related to variation in the species composition of their arthropod diet in combination with different metal levels in the respective prey species, and/or species-specific requirements for essential metals and related variation in physiological regulation of these elements in the bats.


Subject(s)
Chiroptera/metabolism , Environmental Exposure , Forests , Hair/chemistry , Metals, Heavy/analysis , Animals , Chiroptera/classification , Germany , Metals, Heavy/metabolism , Soil/chemistry , Soil Pollutants/analysis , Soil Pollutants/metabolism , Species Specificity
16.
J Cogn Neurosci ; 29(3): 545-559, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28139957

ABSTRACT

Evidence from neuroimaging studies suggests a critical role of hippocampus and inferior frontal gyrus (IFG) in associative relative to item encoding. Here, we investigated similarities and differences in functional brain correlates for associative and item memory as a function of encoding instruction. Participants received either incidental (animacy judgments) or intentional encoding instructions while fMRI was employed during the encoding of associations and items. In a subsequent recognition task, memory performance of participants receiving intentional encoding instructions was higher compared with those receiving incidental encoding instructions. Furthermore, participants remembered more items than associations, regardless of encoding instruction. Greater brain activation in the left anterior hippocampus was observed for intentionally compared with incidentally encoded associations, although activity in this region was not modulated by the type of instruction for encoded items. Furthermore, greater activity in the left anterior hippocampus and left IFG was observed during intentional associative compared with item encoding. The same regions were related to subsequent memory of intentionally encoded associations and were thus task relevant. Similarly, connectivity of the anterior hippocampus to the right superior temporal lobe and IFG was uniquely linked to subsequent memory of intentionally encoded associations. Our study demonstrates the differential involvement of anterior hippocampus in intentional relative to incidental associative encoding. This finding likely reflects that the intent to remember triggers a specific binding process accomplished by this region.


Subject(s)
Association , Brain/physiology , Memory/physiology , Adult , Analysis of Variance , Brain/diagnostic imaging , Brain Mapping , Female , Humans , Judgment/physiology , Magnetic Resonance Imaging , Male , Visual Perception/physiology , Young Adult
17.
Catheter Cardiovasc Interv ; 89(1): E44-E52, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27142257

ABSTRACT

BACKGROUND: Anemia is linked to impaired outcome in patients with cardiovascular diseases. We sought to characterize the impact of baseline anemia on mid-term outcome after transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS: Data of 1201 consecutive TAVI patients were retrospectively analyzed. Baseline anemia was defined according to the WHO (hemoglobin <12g/dl [female], <13g/dl [male]). It was prevalent in 59.0% of patients and associated with a higher preoperative risk (STS-PROM 7.8 ± 5.7 vs. 6.2 ± 4.1%, P < 0.001). Survival was similar at 30 days (90.5 vs. 91.2%, P = 0.626) but NYHA functional capacity was impaired in patients with baseline anemia (classes III/IV: 20.6 vs. 15.6%, P = 0.006). Low baseline hemoglobin (OR 0.85, CI 0.73-0.98, P = 0.025), blood transfusion (OR 2.42, CI 1.38-4.28, P = 0.002), and bleeding complications (OR 2.21, CI 1.27-3.81, P = 0.005) were in addition associated with acute kidney injury after TAVI. Three-year survival was reduced (49.6 vs. 64.9%, P = 0.002) and baseline anemia was linked to increased mid-term mortality (HR 1.43, CI 1.13-1.82, P = 0.003), however its effect was surpassed by the adverse impact of periprocedural complications. CONCLUSIONS: Baseline anemia was associated with increased morbidity and mortality after TAVI. Preprocedural hemoglobin levels need to be assessed for risk stratification and blood conservation management seems essential. As a potentially modifiable target, the role of pretreatment of anemia prior to TAVI remains to be determined. © 2016 Wiley Periodicals, Inc.


Subject(s)
Anemia/complications , Aortic Valve Stenosis/therapy , Aortic Valve , Cardiac Catheterization/methods , Heart Valve Prosthesis Implantation/methods , Aged , Aged, 80 and over , Anemia/blood , Anemia/diagnosis , Anemia/mortality , Aortic Valve/diagnostic imaging , Aortic Valve Stenosis/complications , Aortic Valve Stenosis/diagnostic imaging , Aortic Valve Stenosis/mortality , Biomarkers/blood , Cardiac Catheterization/adverse effects , Cardiac Catheterization/instrumentation , Cardiac Catheterization/mortality , Chi-Square Distribution , Female , Germany , Heart Valve Prosthesis , Heart Valve Prosthesis Implantation/adverse effects , Heart Valve Prosthesis Implantation/instrumentation , Heart Valve Prosthesis Implantation/mortality , Hemoglobins/metabolism , Humans , Kaplan-Meier Estimate , Logistic Models , Male , Odds Ratio , Proportional Hazards Models , Retrospective Studies , Risk Factors , Time Factors , Treatment Outcome
18.
J Cogn Neurosci ; 29(2): 245-253, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27647283

ABSTRACT

Previous research shows that associative memory declines more than item memory in aging. Although the underlying mechanisms of this selective impairment remain poorly understood, animal and human data suggest that dopaminergic modulation may be particularly relevant for associative binding. We investigated the influence of dopamine (DA) receptor genes on item and associative memory in a population-based sample of older adults (n = 525, aged 60 years), assessed with a face-scene item associative memory task. The effects of single-nucleotide polymorphisms of DA D1 (DRD1; rs4532), D2 (DRD2/ANKK1/Taq1A; rs1800497), and D3 (DRD3/Ser9Gly; rs6280) receptor genes were examined and combined into a single genetic score. Individuals carrying more beneficial alleles, presumably associated with higher DA receptor efficacy (DRD1 C allele; DRD2 A2 allele; DRD3 T allele), performed better on associative memory than persons with less beneficial genotypes. There were no effects of these genes on item memory or other cognitive measures, such as working memory, executive functioning, fluency, and perceptual speed, indicating a selective association between DA genes and associative memory. By contrast, genetic risk for Alzheimer disease (AD) was associated with worse item and associative memory, indicating adverse effects of APOE ε4 and a genetic risk score for AD (PICALM, BIN1, CLU) on episodic memory in general. Taken together, our results suggest that DA may be particularly important for associative memory, whereas AD-related genetic variations may influence overall episodic memory in older adults without dementia.


Subject(s)
Aging/genetics , Aging/psychology , Association , Memory , Polymorphism, Single Nucleotide , Receptors, Dopamine/genetics , Alzheimer Disease/genetics , Alzheimer Disease/psychology , Apolipoproteins E/genetics , Cohort Studies , Female , Genotyping Techniques , Humans , Male , Middle Aged , Neuropsychological Tests
19.
Neuroimage ; 118: 146-53, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26054875

ABSTRACT

Associative memory involves binding two or more items into a coherent memory episode. Relative to memory for single items, associative memory declines greatly in aging. However, older individuals vary substantially in their ability to memorize associative information. Although functional studies link associative memory to the medial temporal lobe (MTL) and prefrontal cortex (PFC), little is known about how volumetric differences in MTL and PFC might contribute to individual differences in associative memory. We investigated regional gray-matter volumes related to individual differences in associative memory in a sample of healthy older adults (n=54; age=60years). To differentiate item from associative memory, participants intentionally learned face-scene picture pairs before performing a recognition task that included single faces, scenes, and face-scene pairs. Gray-matter volumes were analyzed using voxel-based morphometry region-of-interest (ROI) analyses. To examine volumetric differences specifically for associative memory, item memory was controlled for in the analyses. Behavioral results revealed large variability in associative memory that mainly originated from differences in false-alarm rates. Moreover, associative memory was independent of individuals' ability to remember single items. Older adults with better associative memory showed larger gray-matter volumes primarily in regions of the left and right lateral PFC. These findings provide evidence for the importance of PFC in intentional learning of associations, likely because of its involvement in organizational and strategic processes that distinguish older adults with good from those with poor associative memory.


Subject(s)
Association Learning/physiology , Brain/anatomy & histology , Memory/physiology , Brain/physiology , Female , Gray Matter/anatomy & histology , Gray Matter/physiology , Humans , Individuality , Magnetic Resonance Imaging , Male , Mental Recall/physiology , Middle Aged , Neuropsychological Tests , Prefrontal Cortex/anatomy & histology , Prefrontal Cortex/physiology , Recognition, Psychology/physiology
20.
PLoS One ; 10(3): e0120562, 2015.
Article in English | MEDLINE | ID: mdl-25781894

ABSTRACT

Species distribution and endangerment can be assessed by habitat-suitability modelling. This study addresses methodical aspects of habitat suitability modelling and includes an application example in actual species conservation and landscape planning. Models using species presence-absence data are preferable to presence-only models. In contrast to species presence data, absences are rarely recorded. Therefore, many studies generate pseudo-absence data for modelling. However, in this study model quality was higher with null samples collected in the field. Next to species data the choice of landscape data is crucial for suitability modelling. Landscape data with high resolution and ecological relevance for the study species improve model reliability and quality for small elusive mammals like Muscardinus avellanarius. For large scale assessment of species distribution, models with low-detailed data are sufficient. For regional site-specific conservation issues like a conflict-free site for new wind turbines, high-detailed regional models are needed. Even though the overlap with optimally suitable habitat for M. avellanarius was low, the installation of wind plants can pose a threat due to habitat loss and fragmentation. To conclude, modellers should clearly state the purpose of their models and choose the according level of detail for species and environmental data.


Subject(s)
Behavior, Animal/physiology , Conservation of Natural Resources , Ecosystem , Models, Biological , Myoxidae/physiology , Animals
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