A dual-pathway architecture enables chronic stress to promote habit formation

Chronic stress can change how we learn and, thus, how we make decisions by promoting the formation of inflexible, potentially maladaptive, habits. Here we investigated the neuronal circuit mechanisms that enable this. Using a multifaceted approach in male and female mice, we reveal a dual pathway, amygdala-striatal, neuronal circuit architecture by which a recent history of chronic stress shapes learning to disrupt flexible goal-directed behavior in favor of inflexible habits. Chronic stress inhibits activity of basolateral amygdala projections to the dorsomedial striatum to impede the action-outcome learning that supports flexible, goal-directed decisions. Stress also increases activity in direct central amygdala projections to the dorsomedial striatum to promote the formation of rigid, inflexible habits. Thus, stress exerts opposing effects on two amygdala-striatal pathways to promote premature habit formation. These data provide neuronal circuit insights into how chronic stress shapes learning and decision making, and help understand how stress can lead to the disrupted decision making and pathological habits that characterize substance use disorders and other psychiatric conditions.

Antithrombotic therapy in children with venous thromboembolism

Antithrombotic therapy has recently become more frequent for the treatment of venous thromboembolism (VTE) in the paediatric population. This can be explained by the increased awareness of morbidities and mortalities of VTE in children, as well as the improved survival rate of children with various kinds of serious illnesses. Considering the large number of years a child is expected to survive, associated morbidities such as postthrombotic syndrome and risk of recurrence can significantly impact on the quality of life in children. Therefore, timely diagnosis, evidence-based treatment and prophylaxis strategies are critical to avoid such complications.

This review summarizes the current literature about the antithrombotic treatment for VTE in infants and children. It guides the paediatric medical care provider for making a logical and justifiable decision.

Antithrombotic therapy in children with venous thromboembolism

Antithrombotic therapy has recently become more frequent for the treatment of venous thromboembolism (VTE) in the paediatric population. This can be explained by the increased awareness of morbidities and mortalities of VTE in children, as well as the improved survival rate of children with various kinds of serious illnesses. Considering the large number of years a child is expected to survive, associated morbidities such as postthrombotic syndrome and risk of recurrence can significantly impact on the quality of life in children. Therefore, timely diagnosis, evidence-based treatment and prophylaxis strategies are critical to avoid such complications. This review summarizes the current literature about the antithrombotic treatment for VTE in infants and children. It guides the paediatric medical care provider for making a logical and justifiable decision.

Activation of lexical and syntactic target language properties in translation

Is reading for translation equal to reading in monolingual contexts? Horizontal/parallel theories of translation propose that normal reading and reading for translation differ because the translator engages in partial reformulation while reading for translating the source text. In contrast, vertical/serial theories assume that the translators first extract the meaning of the message, and only then they proceed to reformulate it. In two experiments, we manipulated lexical and syntactic properties of the target language (TL) while translators read for repetition or for translation. On-line sentence comprehension was affected by the lexical frequency of words in the TL (Experiment 1) and the syntactic congruency between the source language (SL) and TL sentences (Experiment 2). However, the influence of lexical and syntactic TL properties was restricted to the reading for translation task. According to our results, the horizontal view of translation includes code-to-code links between the SL and TL involving at least the lexical and syntactic level of processing.

Soluble CD14 enriched in colostrum and milk induces B cell growth and differentiation

Induction of resting B cell growth and differentiation requires a complex series of temporally coordinated signals that are initiated on contact with activated helper T cells. These signals complement one another, each rendering the B cell susceptible to factors supporting progressive activation. Here, we demonstrate that soluble CD14 (sCD14) bypasses the physiological sequelae of events that limit B cell activation. B cell growth and differentiation in vitro is induced by both native and recombinant forms of sCD14 at nanomolar concentrations. sCD14-mediated cellular activation does not require membrane CD14 expression, depends on a region of CD14 that is not involved in lipopolysaccharide binding, and requires functional Toll-like receptor 4. Consistent with biological activity of sCD14 in vitro, its administration to neonatal mice enhances Ig secretion. The results presented establish sCD14 as a naturally occurring soluble B cell mitogen of mammalian origin.

The role of histidine 231 in thermolysin-like enzymes. A site-directed mutagenesis study

In the zinc metallopeptidases produced by the genus Bacillus, an active site histidine has been proposed to either stabilize the transition state in catalysis by donating a hydrogen bond to the hydrated peptide (Matthews, B. W. (1988) Acc. Chem. Res. 21, 333-340) or to polarize a water molecule, which subsequently attacks the peptidyl bond (Mock, W. L., and Aksamawati, M. (1994) Biochem. J. 302, 57-68). Site-directed mutagenesis techniques have been used to change this residue in the zinc endopeptidase from Bacillus stearothermophillus to either phenylalanine or alanine. At pH 7.0, the kcat/Km values of the substrate leucine enkephalin for the phenylalanine and alanine mutants were reduced by factors of 430- and 500-fold, respectively, as compared with the wild-type enzyme, mostly due to changes in kcat. In addition, the enzymatic activities of the mutant enzymes showed little pH dependence in the alkaline range, unlike the wild-type enzyme. The mutations did not greatly alter the binding affinities of inhibitors containing sulfydryl groups to chelate the active site zinc, while those of inhibitors containing hydroxamate or carboxylate zinc-chelating groups were increased between 80- and 250-fold. The largest change in the binding affinity of an inhibitor (> 5 orders of magnitude) was found with the proposed transition state mimic, phosphoramidon. The results are generally in agreement with x-ray crystallography studies and favor the involvement of the active site histidine in transition state binding.