Pushing with the pigtail: A novel approach to placing the MitraClip in a patient with a severely restricted posterior mitral leaflet

The MitraClip is an US Food and Drug Administration‐approved device for inoperable patients with severe degenerative mitral regurgitation (MR) and is under investigation for use in patients with severe functional MR. Simultaneously grasping both leaflets of the mitral valve can be technically challenging, however, in patients with a restricted posterior leaflet. We present one such case in which a pigtail catheter, placed retrograde into the left ventricle, was able to push the ventricular surface of the posterior leaflet into closer approximation with the anterior leaflet, and facilitate successful clip placement. We provide this report in hopes that it will provide a useful strategy for interventionalists faced with this challenging situation. © 2014 Wiley Periodicals, Inc.     

Cross-cultural gene− environment interactions in depression,post-traumatic stress disorder,and the cortisol awakening response: FKBP5 polymorphisms and childhood trauma in South Asia

Abstract

Despite increased attention to global mental health, psychiatric genetic research has been dominated by studies in high-income countries, especially with populations of European descent. The objective of this study was to assess single nucleotide polymorphisms (SNPs) in the FKBP5 gene in a population living in South Asia. Among adults in Nepal, depression was assessed with the Beck Depression Inventory (BDI), post-traumatic stress disorder (PTSD) with the PTSD Checklist-Civilian Version (PCL-C), and childhood maltreatment with the Childhood Trauma Questionnaire (CTQ). FKBP5 SNPs were genotyped for 682 participants. Cortisol awakening response (CAR) was assessed in a subsample of 118 participants over 3 days. The FKBP5 tag-SNP rs9296158 showed a main effect on depressive symptoms (p = 0.03). Interaction of rs9296158 and childhood maltreatment predicted adult depressive symptoms (p = 0.02) but not PTSD. Childhood maltreatment associated with endocrine response in individuals homozygous for the A allele, demonstrated by a negative CAR and overall hypocortisolaemia in the rs9296158 AA genotype and childhood maltreatment group (p < 0.001). This study replicated findings related to FKBP5 and depression but not PTSD. Gene–environment studies should take differences in prevalence and cultural significance of phenotypes and exposures into account when interpreting cross-cultural findings.     

d‐amino acid oxidase knockout (Dao−/−) mice show enhanced short‐term memory performance and heightened anxiety,but no sleep or circadian rhythm disruption

d ‐amino acid oxidase (DAO, DAAO) is an enzyme that degrades d ‐serine, the primary endogenous co‐agonist of the synaptic N‐methyl‐d ‐aspartate receptor. Convergent evidence implicates DAO in the pathophysiology and potential treatment of schizophrenia. To better understand the functional role of DAO, we characterized the behaviour of the first genetically engineered Dao knockout (Dao^?/?) mouse. Our primary objective was to assess both spatial and non‐spatial short‐term memory performance. Relative to wildtype (Dao^+/+) littermate controls, Dao^?/? mice demonstrated enhanced spatial recognition memory performance, improved odour recognition memory performance, and enhanced spontaneous alternation in the T‐maze. In addition, Dao^?/? mice displayed increased anxiety‐like behaviour in five tests of approach/avoidance conflict: the open field test, elevated plus maze, successive alleys, light/dark box and novelty‐suppressed feeding. Despite evidence of a reciprocal relationship between anxiety and sleep and circadian function in rodents, we found no evidence of sleep or circadian rhythm disruption in Dao^?/? mice. Overall, our observations are consistent with, and extend, findings in the natural mutant ddY/Dao^? line. These data add to a growing body of preclinical evidence linking the inhibition, inactivation or deletion of DAO with enhanced cognitive performance. Our results have implications for the development of DAO inhibitors as therapeutic agents.     

Orexin‐1 receptor signaling increases motivation for cocaine‐associated cues

The orexin/hypocretin system is involved in multiple cocaine addiction processes that involve drug‐associated environmental cues, including cue‐induced reinstatement of extinguished cocaine seeking and expression of conditioned place preference. However, the orexin system does not play a role in several behaviors that are less cue‐dependent, such as cocaine‐primed reinstatement of extinguished cocaine seeking and low‐effort cocaine self‐administration. We hypothesized that cocaine‐associated cues, but not cocaine alone, engage signaling at orexin‐1 receptors (OX1Rs), and this cue‐engaged OX1R signaling increases motivation for cocaine. Motivation for cocaine was measured in Sprague–Dawley rats with behavioral‐economic demand curve analysis after pretreatment with the OX1R antagonist SB‐334867 (SB) or vehicle with and without light + tone cues. Demand for cocaine was higher when cocaine‐associated cues were present, and SB only reduced cocaine demand in the presence of these cues. We then investigated whether cocaine demand was linked to the cued reinstatement of cocaine seeking, as both procedures are partially driven by cocaine‐associated cues in an orexin‐dependent manner. SB blocked cue‐induced reinstatement behavior, and baseline demand predicted SB efficacy with the largest effect in high‐demand animals, i.e. animals with the greatest cue‐dependent behavior. We conclude that OX1R signaling increases the reinforcing efficacy of cocaine‐associated cues but not that of cocaine alone. This supports our view that orexin plays a prominent role in the ability of conditioned cues to activate motivational responses.     

Initiating protease with modular domains interacts with β-glucan recognition protein to trigger innate immune response in insects

The autoactivation of an initiating serine protease upon binding of pattern recognition proteins to pathogen surfaces is a crucial step in eliciting insect immune responses such as the activation of Toll and prophenoloxidase pathways. However, the molecular mechanisms responsible for autoactivation of the initiating protease remains poorly understood. Here, we investigated the molecular basis for the autoactivation of hemolymph protease 14 (HP14), an initiating protease in hemolymph of Manduca sexta, upon the binding of β-1,3-glucan by its recognition protein, βGRP2. Biochemical analysis using HP14 zymogen (proHP14), βGRP2, and the recombinant proteins as truncated forms showed that the amino-terminal modular low-density lipoprotein receptor class A (LA) domains within HP14 are required for proHP14 autoactivation that is stimulated by its interaction with βGRP2. Consistent with this result, recombinant LA domains inhibit the activation of proHP14 and prophenoloxidase, likely by competing with the interaction between βGRP2 and LA domains within proHP14. Using surface plasmon resonance, we demonstrated that immobilized LA domains directly interact with βGRP2 in a calcium-dependent manner and that high-affinity interaction requires the C-terminal glucanase-like domain of βGRP2. Importantly, the affinity of LA domains for βGRP2 increases nearly 100-fold in the presence of β-1,3-glucan. Taken together, these results present the first experimental evidence to our knowledge that LA domains of an insect modular protease and glucanase-like domains of a βGRP mediate their interaction, and that this binding is essential for the protease autoactivation. Thus, our study provides important insight into the molecular basis underlying the initiation of protease cascade in insect immune responses.Extracellular protease cascades play an essential role in a variety of biological processes including embryonic development (1) and host defenses such as blood coagulation and the complement system (2, 3). Protease cascades also function in insect innate immune responses such as melanization and antimicrobial peptide synthesis by inducing the prophenoloxidase (proPO) and Toll pathways, respectively (3–5).In protease cascades, inactive protease zymogens that circulate in an extracellular milieu become sequentially activated in pathways beginning with an initiating modular serine protease, which autoactivates in response to internal or external signals. In hemolymph (insect blood), pathogen-associated molecular patterns (PAMPs) such as peptidoglycans in bacteria and β-1,3-glucan in fungi are first detected by pathogen recognition receptors (PRRs) such as peptidoglycan recognition proteins (PGRPs) and β-1,3-glucan recognition proteins (βGRPs) (4–8). As demonstrated by genetic and biochemical studies of protease cascades in insect immune responses, those recognition signals are integrated by an initiating protease (9–12). The initiating protease then undergoes autoactivation, and the activated form of the protease subsequently activates downstream serine protease zymogens in the proPO and Toll activation pathways. Hemolymph protease 14 in Manduca sexta (HP14) is one such initiating protease. Biochemical studies have shown that HP14 zymogen (proHP14) autoactivates in the presence of peptidoglycan (9) or β-1,3-glucan and a β-1,3-glucan recognition protein (βGRP1 or βGRP2) (10, 13). The molecular basis underlying HP14 autoactivation, however, still remains to be explored.HP14 has a carboxyl-terminal serine protease domain (SP) and a series of amino-terminal modular domains that presumably play an important role in autoactivation and/or proteolytic cleavage of downstream protease zymogens (9). These modules include low-density lipoprotein receptor class A repeats (LAs, also called complement-type repeats, CRs), a complement control protein module (CCP), and a unique cysteine-rich domain (7C) (Fig. 1). HP14 orthologs in other insects, Tenebrio molitor (MSP) (11) and Drosophila melanogaster (ModSP) (12), share similar domain organizations. Although little is known about the role of those modular domains in initiating proteases, both LA and CCP modules have been shown to mediate protein–protein/carbohydrate interactions in physiological and immune processes of mammals. For instance, LA domains represent building blocks of the low-density lipoprotein receptor (LDLr) family and its related proteins (LRP) (14, 15), and they interact with many extracellular ligands (16, 17). CCP modules are also found in a number of proteins in the vertebrate complement system including serine proteases that initiate the classical and lectin pathways (C1r and MASPs).Open in a separate windowFig. 1.Domain architecture of M. sexta βGRP2, HP14, and their recombinant truncated forms. βGRP2 consists of an amino-terminal carbohydrate-binding module (CBM) and a carboxyl-terminal glucanase-like domain. No β-1,3-glucanase activity was observed because of the lack of conserved catalytic residues responsible for activity (8). For HP14, four low-density lipoprotein receptor class A repeats (LA2–LA5), complement control protein domain (CCP), a cysteine-rich domain (7C), and catalytic serine protease domain (SP) are indicated. LA1 is not shown in the diagram, because it was removed before purification of proHP14 from hemolymph and from the recombinant LA1–LA5 before purification from cell culture medium, perhaps due to intracellular processing (10). The disulfide bond between 7C and SP domains and the L404-V405 cleavage site for autoactivation are also indicated. Also shown with βGRP2 and HP14 are the recombinant constructs used in this study (N-βGRP2, rHP14-LA, rHP14-CCP, and CCP-7C-SP).Here, we directly investigated the role of modular domains of HP14 to better understand the initial event of the immune protease cascade at a molecular level. Our biochemical and biophysical analyses reveal an essential role for LA domains in HP14 autoactivation, resulting from direct interaction with βGRP2. These results, together with our previous studies showing the self-association of insect βGRPs upon binding β-1,3-glucan (18, 19), provide an improved model for the molecular basis underlying the initiation of serine protease cascades for insect immune responses.     

Effects of prior mental effort on picture processing: An ERP investigation

The current study examined the aftereffects of mental effort on the processing of picture stimuli using neural measures. Ninety‐seven healthy young adults were randomly assigned to exercise more versus less mental effort on a writing task. Then participants viewed positive, negative, and neutral affective images while P1, N1, P2, N2, P3, and late positive potential (LPP) magnitudes to the images were assessed. We found that performing the more (versus less) effortful writing task caused more negative N2 amplitudes to all images. In addition, and consistent with past research, emotional (versus neutral) images elicited more positive amplitudes on the N2, P3, and LPP components. Thus, prior mental effort appeared to reduce early attentional engagement with visual stimuli but did not diminish later attention modulation by emotional content. These findings suggest novel implications for understanding the behavioral aftereffects of mental effort and self‐control.