Tracing the time course of n − 2 repetition costs in task switching

In order to flexibly adapt to a permanently changing environment, it is necessary to inhibit previously activated but now irrelevant processing pathways. Empirically, this inhibition manifests itself only indirectly in terms of a cost of reengaging a previously inhibited pathway (n ? 2 repetition costs). While imaging studies suggest an involvement of the prefrontal cortex in this type of inhibition, it has recently been argued that the underlying processes are implicated not in triggering inhibition, but in overcoming it. To disentangle these processes on a behavioral level, we investigated the time course of inhibition using a cued task switching paradigm. The response–cue interval (between the response of trial n ? 1 and the cue of trial n) was varied in five steps to capture its influence on inhibition in a fine-grained manner. The results suggest that the impact of inhibitory processes increases during the first 200–300 ms after the response of the previous trial, reaches its full extent with about 300 ms, and starts to diminish after that. Therefore, future research on the neural correlates of n ? 2 repetition costs should employ techniques with a high temporal resolution that are able to capture this presumed time course of inhibitory processes.     

Serum brain‐derived neurotrophic factor and platelet activation evaluated by soluble P‐selectin and soluble CD‐40‐ligand in patients with acute myocardial infarction

Little is known about the role of neurotrophins (NT) under adult vascular homeostasis in normal and pathological conditions. The NT family, including nerve growth factor and brain‐derived neurotrophic factor (BDNF) are expressed in atherosclerotic vessels. Previous studies demonstrated that plasma BDNF levels were increased in the coronary circulation in patients with unstable angina. However, the role of BDNF during the onset and evolution of unstable angina remains to be elucidated. The objective of this study was to evaluate the relationship between BDNF, functional parameters and biological markers associated with inflammatory processes and platelet activation. BDNF serum levels were assessed in patients with acute myocardial infarction (MI) (n = 20) or stable angina pectoris (SAP) (n = 20) who underwent coronary angiography. Serum levels of IL‐6, MCP1, sVCAM, soluble CD‐40‐ligand (sCD40L) and soluble P‐selectin (sP‐selectin) were measured simultaneously by flux cytometry. Median BDNF levels were higher in the MI than in the SAP group (1730 vs. 877 pg/mL, respectively; P = 0.025). In MI patients, we observed a significant correlation between BDNF and sP‐selectin (r = 0.58, P = 0.023), although we found a non‐significant trend between BDNF and sCD40L (r = +0.35, P = 0.144). By contrast, no such correlation was observed in SAP patients (r = ?0.22, P = 0.425). No difference was observed between the two groups regarding baseline demographics, risk factors, biological data and angiographic findings. The study suggests that BDNF serum levels in MI patients could be related to platelet activation and the inflammatory response. Further studies are needed to investigate the role of NT in the setting of acute MI.     

Collagen fibril organization in the pregnant endometrium of decorin-deficient mice

In the pregnant mouse endometrium, collagen fibrillogenesis is characterized by the presence of very thick collagen fibrils which are topographically located exclusively within the decidualized stroma. This dynamic biological process is in part regulated by the small leucine-rich proteoglycans decorin and biglycan. In the present study we utilized wild-type (Dcn^+/+) and decorin-deficient (Dcn^−/−) time-pregnant mice to investigate the evolution of non-decidualized and decidualized collagen matrix in the uterine wall of these animals. Ultrastructural and morphometric analyses revealed that the organization of collagen fibrils in the pregnant endometrium of both non-decidualized and decidualized stroma showed a great variability of shape and size, regardless of the genotype. However, the decidualized endometrium from Dcn^−/− mice contained fibrils with larger diameter and more irregular contours as compared to the wild-type littermates. In the Dcn^−/− animals, the proportion of thin (10–50 nm) fibrils was also higher as compared to Dcn^+/+ animals. On day 7 of pregnancy, biglycan was similarly localized in the decidualized endometrium in both genotypes. Lumican immunostaining was intense both in decidualized and non-decidualized stroma from Dcn^−/− animals. The present results support previous findings suggesting that decorin participates in uterine collagen fibrillogenesis. In addition, we suggest that the absence of decorin disturbs the process of lateral assembly of thin fibrils, resulting in very thick collagen fibrils with irregular profiles. Our data further suggest that decorin, biglycan and lumican might play an interactive role in collagen fibrillogenesis in the mouse endometrium, a process modulated according to the stage of pregnancy.     

Imitation of para-phonological detail following left hemisphere lesions

Imitation in speech refers to the unintentional transfer of phonologically irrelevant acoustic-phonetic information of auditory input into speech motor output. Evidence for such imitation effects has been explained within the framework of episodic theories. However, it is largely unclear, which neural structures mediate speech imitation and how imitation is related with verbal repetition. Two experiments were conducted, a standard repetition task, and a transformation task requiring phonetic manipulation of the presented auditory nonword stimuli. Nonword materials varied sub-phonemically in word stress (pitch elevation magnitude; PEM) and in a parameter related to speaking style, i.e., the explicitness of final schwa-syllables (SSE). We examined speech imitation in 10 healthy participants, 10 patients with phonological impairments after left hemisphere lesions, and 11 patients with right hemisphere lesions. In repetition, significant imitation of SSE and PEM was observed in all groups of participants. In transformation, imitation occurred in healthy participants and in the patients with right hemisphere lesions, whereas no imitation was observed in the patient group with left hemisphere lesions. Voxel-based lesion-symptom mapping revealed that different areas within the left temporal plane influenced the degree of imitation of phonetic and prosodic detail in repetition.     

The Peer Aggressive and Reactive Behavior Questionnaire (Parb-Q): Measurement Invariance Across Italian and Brazilian Children, Gender and Age

This study examines measurement invariance, reliability and scores differences of the Peer Aggressive and Reactive Behaviors Questionnaire (PARB-Q) across Italian and Brazilian children, gender and age. Participants were 587 Italian and 727 Brazilian children, aged 7–13 years from 12 elementary schools. The PARB-Q is a brief self-report instrument composed by two scales that assess aggressive behavior and reactions to peer aggression. Multigroup confirmatory factor analyses indicated full measurement invariance of the PARB-Q across groups based on country, gender and age, providing support for the unidimensionality of the first scale (direct peer aggression, PA) and a 3-factor model of the second scale (reactive aggression, RA; seeking teacher support, STS; internalizing reaction, IR). Reliability indices were good for all factors. Italian children reported a higher frequency of PA and a lower frequency of IR than the Brazilian children. Boys scored higher than girls on PA and RA, while girls scored higher than boys on STS and IR. Younger children reported a lower frequency of PA and a higher frequency of STS than older children. Results provide support for structure validity and reliability of the PARB-Q in two countries and information on differences related to gender, age and culture in peer relationships in elementary school.     

Presence of Polycyclic Aromatic Hydrocarbons in Rubber Packaging Materials and in Parenteral Formulations Stored in Bottles With Rubber Stoppers

Background: Rubber closures are the primary packaging material for sterile preparations intended for repeated use. Important features of rubber closures are achieved after additives are added to the elastomeric material that compounds the rubber. Among these additives is carbon black. Because of its origin, carbon black may contain polycyclic aromatic hydrocarbons (PAHs). The U.S. Environmental Protection Agency has identified 16 priority PAHs on the basis of concerns that they cause or might cause cancer in animals and humans. Regulatory agencies impose carbon black purity specifications based on limits for total PAHs (0.5 mg/kg) and benzo[a]pyrene (5 μg/kg) or benzo[a]pyrene only (250 μg/kg). PAHs in rubber packaging used for pharmaceutical formulations and in parenteral products stored in containers with rubber stoppers were investigated. Methods: To this end, the method proposed by the National Institute for Occupational Safety and Health—based on high‐performance liquid chromatography with ultraviolet and fluorescence detection—was adapted to determine the levels of PAHs in rubber stoppers (gray and red) and in lipid emulsions and amino acid solutions stored in bottles with rubber stoppers. Results: The rubber materials were shown to contain 12 PAHs, in concentrations ranging from 0.25–3.31 µg/g. Only 1 of 18 samples (11 amino acid solutions and 7 lipid emulsions) was uncontaminated. The most prevalent contaminants were pyrene, benzo[a]pyrene, and fluoranthene. The total PAH concentrations in the samples ranged from 0.11–5.96 µg/mL. Conclusion: Components of parenteral nutrition may be contaminated with PAHs, and rubber stoppers represent a potential source of these contaminants.