“That's not my arm”: A hypnotic analogue of somatoparaphrenia

Introduction. “Instrumental hypnosis” allows researchers to model clinical symptoms in the laboratory, creating “virtual patients” with reversible disturbances in, for example, perception, action, memory, or belief. We used hypnosis to temporarily recreate somatoparaphrenia, a delusional belief that one's own limb belongs to someone else.

Methods. We compared a “Fully Formed” somatoparaphrenia suggestion with a “Factor 1 + Factor 2” suggestion that attempted to generate the delusional belief from analogues of its hypothesised underlying factors (i.e., paralysis plus disrupted critical belief evaluation). We tested and then challenged subjects’ responses to these suggestions.

Results. Although many hypnotic subjects experienced temporary paralysis, only a minority claimed their arm did not belong to them. Notably, the Fully Formed suggestion was more successful in recreating features of somatoparaphrenia than the Factor 1 + Factor 2 suggestion. In response to the challenges, some of those who developed temporary somatoparaphrenia maintained their belief throughout the hypnosis session.

Conclusions. We discuss these findings in terms of the “two-factor” theory of delusions and we highlight the advantages versus disadvantages of using hypnosis to explore such delusional beliefs in the laboratory.     

Interface Behavior and Interface Tensile Strength of a Hardened Concrete Mixture with a Coarse Aggregate for Additive Manufacturing

3D concrete printing technology (3DCP) is a relatively new technology that was first established in the 1990s. The main weakness of the technology is the interface strength between the extruded layers, which are deposited at different time intervals. Consequently, the interface strength is assumed to vary in relation to the time of concrete casting. The proposed experimental study investigated the behavior of a hardened concrete mixture containing coarse aggregates that were up to 8 mm in size, which is rather unusual for 3DCP technology. The resulting direct tensile strength at the layer interface was investigated for various time intervals of deposition from the initial mixing of concrete components. To better understand the material behavior at the layer interface area, computed tomography (CT) scanning was conducted, where the volumetric and area analysis enabled validation of the pore size and count distribution in accordance with the layer deposition process. The analyzed CT data related the macroscopic anisotropy and the resulting crack pattern to the temporal and spatial variability that is inherent to the additive manufacturing process at construction scales while providing additional insights into the porosity formation during the extrusion of the cementitious composite. The observed results contribute to previous investigations in this field by demonstrating the causal relationships, namely, how the interface strength development is determined by time, deposition process, and pore size distribution. Moreover, in regard to the printability of the proposed coarse aggregate mixture, the specific time interval is presented and its interplay with interface roughness and porosity is discussed.     

Recent advances in the diagnostic pathology of salivary carcinomas

This review concentrates on the most important developments since the WHO classification of 2005. In particular, the identification of specific translocations is revolutionising the way salivary tumours are considered and will have a major impact on future diagnostic practice. This is true so far in four malignancies: mammary analogue secretory, mucoepidermoid, adenoid cystic and hyalinising clear cell carcinomas. In each, the gene rearrangement is found in 80 % or more of cases. Two 2014 publications have added further possible candidates with molecular abnormalities to the list (cribriform adenocarcinoma of the tongue and minor salivary glands and epithelial-myoepithelial carcinoma), but these findings have yet to be confirmed by other investigators. The advances in molecular pathology have also allowed re-evaluation of the morphology; for example, it is now realised that the histological spectrum of hyalinising clear cell carcinoma includes intracellular mucin in over half of cases, as well as tumours with only scanty clear cells. In a separate development, it is now proposed that salivary duct carcinoma can be subdivided along molecular lines, in ways analogous to breast cancer, suggesting new therapeutic prospects in an otherwise highly aggressive malignancy.     

Binding of Pro-Gly-Pro at the active site of leukotriene A4 hydrolase/aminopeptidase and development of an epoxide hydrolase selective inhibitor

Leukotriene (LT) A₄ hydrolase/aminopeptidase (LTA4H) is a bifunctional zinc metalloenzyme that catalyzes the committed step in the formation of the proinflammatory mediator LTB₄. Recently, the chemotactic tripeptide Pro-Gly-Pro was identified as an endogenous aminopeptidase substrate for LTA₄ hydrolase. Here, we determined the crystal structure of LTA₄ hydrolase in complex with a Pro-Gly-Pro analog at 1.72 Å. From the structure, which includes the catalytic water, and mass spectrometric analysis of enzymatic hydrolysis products of Pro-Gly-Pro, it could be inferred that LTA₄ hydrolase cleaves at the N terminus of the palindromic tripeptide. Furthermore, we designed a small molecule, 4-(4-benzylphenyl)thiazol-2-amine, denoted ARM1, that inhibits LTB₄ synthesis in human neutrophils (IC₅₀ of ∼0.5 μM) and conversion of LTA₄ into LTB₄ by purified LTA4H with a K_i of 2.3 μM. In contrast, 50- to 100-fold higher concentrations of ARM1 did not significantly affect hydrolysis of Pro-Gly-Pro. A 1.62-Å crystal structure of LTA₄ hydrolase in a dual complex with ARM1 and the Pro-Gly-Pro analog revealed that ARM1 binds in the hydrophobic pocket that accommodates the ω-end of LTA₄, distant from the aminopeptidase active site, thus providing a molecular basis for its inhibitory profile. Hence, ARM1 selectively blocks conversion of LTA₄ into LTB₄, although sparing the enzyme’s anti-inflammatory aminopeptidase activity (i.e., degradation and inactivation of Pro-Gly-Pro). ARM1 represents a new class of LTA₄ hydrolase inhibitor that holds promise for improved anti-inflammatory properties.Leukotriene (LT) A₄ hydrolase/aminopeptidase (EC 3.3.2.6) is a bifunctional zinc metalloenzyme that catalyzes the formation of the potent chemotactic agent LTB₄, a key lipid mediator in the innate immune response (1, 2). Previous work has shown that LTA₄ hydrolase (LTA4H) is an aminopeptidase with high affinity for N-terminal arginines of various synthetic tripeptides (3, 4). The two enzyme activities of LTA4H are exerted via distinct but overlapping active sites and depend on the catalytic zinc, bound within the signature HEXXH-(X)₁₈-E, typical of M1 metallopeptidases (5–7). In LTA4H, His295, His299, and Glu318 are the zinc-binding ligands, whereas Glu296 is the general base catalyst for peptide hydrolysis (8, 9).LTA4H’s crystal structure has been determined (10). The enzyme folds into an N-terminal domain, a catalytic domain, and a C-terminal domain, each with ∼200 amino acids. The interface of the domains forms a cavity, where the active site is located (Fig. 1). The cavity narrows at the zinc-binding site, forming a tunnel into the catalytic domain. The opening and wider parts of the cavity are highly polar; the tunnel is more hydrophobic. The cavity is mostly defined by the catalytic and C-terminal domains; part of the tunnel is defined by the N-terminal domain. Bound substrate is in contact with all three domains.Open in a separate windowFig. 1.Position and extension of the active center in LTA4H. Cartoon representation of the structure of LTA4H with a tunnel for LTA₄ (red mesh) and peptide substrates (blue mesh). The catalytic zinc (yellow sphere) is located in a wide section of the active site from which a narrow, L-shaped, hydrophobic tunnel protrudes ∼15 Å deeper into the protein. LTA₄ is believed to bind with its ω-end at the end of the hydrophobic tunnel. The volume of the active center was calculated in CAVER (31).Recently, it was discovered that LTA4H cleaves and inactivates the chemotactic tripeptide Pro-Gly-Pro, thus identifying a previously unrecognized endogenous, physiologically significant aminopeptidase substrate (11). Inasmuch as Pro-Gly-Pro attracts neutrophils and promotes inflammation, these data also suggest that LTA4H plays dual and opposite roles during an inflammatory response (i.e., production of chemotactic LTB₄, as well as inactivation of chemotactic Pro-Gly-Pro). Previous efforts to develop inhibitors of LTA4H have used the aminopeptidase activity for screening purposes, and these molecules therefore block both catalytic activities of LTA4H (12).Here, we used crystallography, MS, and a stable peptide analog to determine the binding mode of Pro-Gly-Pro at the active site of LTA4H, as well as the mechanism of peptide cleavage. Based on the structure, we also designed a lead compound that selectively blocks the conversion of LTA₄ into LTB₄, although sparing the hydrolysis of Pro-Gly-Pro.     

Decreased serum antioxidant capacity in patients with Wilson disease is associated with neurological symptoms

Background &; Aims

Wilson disease (WD) is an inherited disorder of copper disposition caused by an ATP7B transporter gene mutation, leading to copper accumulation in predisposed tissues. In addition to a genetic predisposition, other factors are likely to contribute to its clinical manifestation. The aim of the study was to assess whether oxidative stress affects the phenotypic manifestation of WD.

Methods

In 56 patients with WD (29 men; 26 with the hepatic form, 22 with the neurologic form, and eight asymptomatic; mean age 38.5?±?12 years), total serum antioxidant capacity (TAC) and inflammatory parameters (hs-CRP, IL-1??, IL-2, IL-6, IL-10, and TNF-??) were analyzed and related to the clinical manifestation, and mutations of the ATP7B gene. The control group for the TAC and inflammatory parameters consisted of 50 age- and gender-matched healthy individuals.

Results

WD patients had a significantly lower TAC (p?Conclusions Data from our study suggest that the increased oxidative stress contributes significantly to the clinical manifestation of WD; as a lower TAC is associated with the neurological symptoms in WD patients.     

Pancreatic Islet Vasculature Adapts to Insulin Resistance Through Dilation and Not Angiogenesis

Pancreatic islets adapt to insulin resistance through a complex set of changes, including β-cell hyperplasia and hypertrophy. To determine if islet vascularization changes in response to insulin resistance, we investigated three independent models of insulin resistance: ob/ob, GLUT4^+/−, and mice with high-fat diet–induced obesity. Intravital blood vessel labeling and immunocytochemistry revealed a vascular plasticity in which islet vessel area was significantly increased, but intraislet vessel density was decreased as the result of insulin resistance. These vascular changes were independent of islet size and were only observed within the β-cell core but not in the islet periphery. Intraislet endothelial cell fenestration, proliferation, and islet angiogenic factor/receptor expression were unchanged in insulin-resistant compared with control mice, indicating that islet capillary expansion is mediated by dilation of preexisting vessels and not by angiogenesis. We propose that the islet capillary dilation is modulated by endothelial nitric oxide synthase via complementary signals derived from β-cells, parasympathetic nerves, and increased islet blood flow. These compensatory changes in islet vascularization may influence whether β-cells can adequately respond to insulin resistance and prevent the development of diabetes.Pancreatic islets are highly vascularized, and this feature is critical for β-cells to rapidly sense the blood glucose and secrete insulin into the systemic circulation (1,2). Islet vascularization begins early in pancreas development and is maintained in adulthood as a consequence of islet cell production of angiogenic factors such as vascular endothelial growth factor-A (VEGF-A) and angiopoietin-1 (Ang-1) (3–6). These factors recruit endothelial cells (ECs), stimulate blood vessel growth and maturation, and in the case of VEGF-A, promote formation of EC fenestrations (5,6). In addition, ECs adjacent to pancreatic epithelium reciprocally influence islet cell differentiation and development (7,8).β-Cells have a remarkable ability to respond to changes in an organism’s metabolic state, such as changes in the blood glucose or increased insulin requirements. For example, when insulin resistance develops, β-cells of the pancreatic islet can dramatically increase insulin production and secretion with an increase of β-cell mass, thus maintaining normoglycemia (9,10). In this way, mouse models with marked insulin resistance and humans with obesity-related insulin resistance are hyperinsulinemic but not hyperglycemic. The mechanisms underlying this β-cell adaptation to insulin resistance and their subsequent failure in some individuals who develop type 2 diabetes are incompletely understood.Because of the highly vascularized state of pancreatic islets and the marked changes in β-cell size and number in the setting of insulin resistance, we hypothesized that the islet vasculature must adapt to these changes in β-cell mass and insulin requirements. We envisioned that a hyperplastic islet, like a growing tumor mass, would increase production of angiogenic factors to increase its vascular supply with expanding β-cell mass (11). To test this hypothesis, we examined islet vascularization in three mouse models of insulin resistance and found, unexpectedly, that islet vessel density was decreased, not increased, and that the intraislet vasculature became markedly dilated whereas vessels in the exocrine tissue were unchanged. The dilation of intraislet capillaries was independent of islet size, suggesting the vascular adaptation may primarily support increased β-cell insulin secretory demand rather than β-cell mass expansion. Moreover, these vascular changes were accompanied by an increase in islet parasympathetic innervation. Our results indicate that the metabolic state influences islet angioarchitecture and innervation, suggesting that islet neurovascular remodeling may influence whether β-cells can adequately respond to insulin resistance and maintain normoglycemia.