Reducing RBM20 activity improves diastolic dysfunction and cardiac atrophy

Impaired diastolic filling is a main contributor to heart failure with preserved ejection fraction (HFpEF), a syndrome with increasing prevalence and no treatment. Both collagen and the giant sarcomeric protein titin determine diastolic function. Since titin's elastic properties can be adjusted physiologically, we evaluated titin-based stiffness as a therapeutic target. We adjusted RBM20-dependent cardiac isoform expression in the titin N2B knockout mouse with increased ventricular stiffness. A ~50 % reduction of RBM20 activity does not only maintain cardiac filling in diastole but also ameliorates cardiac atrophy and thus improves cardiac function in the N2B-deficient heart. Reduced RBM20 activity partially normalized gene expression related to muscle development and fatty acid metabolism. The adaptation of cardiac growth was related to hypertrophy signaling via four-and-a-half lim-domain proteins (FHLs) that translate mechanical input into hypertrophy signals. We provide a novel link between cardiac isoform expression and trophic signaling via FHLs and suggest cardiac splicing as a therapeutic target in diastolic dysfunction. KEY MESSAGE: Increasing the length of titin isoforms improves ventricular filling in heart disease. FHL proteins are regulated via RBM20 and adapt cardiac growth. RBM20 is a therapeutic target in diastolic dysfunction

The Foreign Direct Investment Location Decision: A Contingency Model of the Foreign Direct Investment Location Decision-Making Process

Despite considerable prior research into foreign direct investment (FDI) location decisions, our understanding of the processes underlying such decisions is still limited. Findings from work based in the economics and behavioral theories of the multinational enterprise (MNE) both acknowledge that FDI is not a point-of-time decision but a gradual process that yields important changes over its duration. However, these competing traditions both fall short when attempting to portray the actual process by which FDI location decisions are made by managers in MNEs. This gap has been recently attributed to two interrelated limitations. Firstly, level of analysis concerns have artificially separated managerial decision-making processes from the organizational and environmental structures within which they are made. Secondly, because of the complexity inherent in the FDI location decision environment, the study of these decisions has not taken contextual factors into consideration. This study addresses three important questions in order to build our understanding of the FDI location decision-making processes: (1) What are the decision-making processes that lead to FDI location choice? (2) What is the impact of contextual variables on FDI location decision-making processes at different levels of analysis, and are there any patterns of variation in decision processes under different decision conditions? (3) What factors drive final FDI location choice, and can a useful framework or theory be developed that links FDI location decision-making processes and context to drivers of FDI location choice? In order to address level of analysis concerns, the study places the manager at the center of the FDI location decision in modeling and in research, a strategy recommended by an emerging stream of behavioral-focused international business research (Aharoni, 2010; Buckley et al., 2007; Devinney, 2011). By examining FDI location decisions from the perspective of the managers who implement them, it is possible to clarify the nature of processes that lead to FDI location choice, and identify the impact of different elements of decision maker, firm and environmental context on such processes. The conceptual framework builds on Aharoni’s (1966) pivotal research while incorporating findings from broader behavioral managerial decision models and international business research. The framework is based on the assumption that FDI location decision-making processes and final choice are contingent upon interactions between the environmental, firm and decision maker context under which the decision is made. The research was undertaken in three phases. Phase 1 included a literature review that covered research on the MNE, internationalization, and decision making. The findings of the review identified key aspects of FDI location decision context and led to the development of an initial contingency framework of strategic decision making. Phase 2 consisted of an exploratory case study of twenty four FDI location decisions. The initial contingency framework developed during the literature review was used during this stage to identify the relationship between decision-making processes and contextual variables at the case decisions. By drawing on results from the exploratory research, an initial conceptual model and a set of propositions were developed. In Phase 3, twenty case studies were theoretically sampled from a pool of MNEs of varying size and parent-country nationality within the knowledge-based industries. The data collection and analysis followed a process, event-driven approach to case study research involving the mapping of key sequences of events as well as within- and cross-case analysis. The results identify the key elements of the decision process that explain FDI location behavior and develop a framework that links them together and makes them sensible. The four key elements of the FDI location decision that comprise the framework include: (i) the process, (ii) the context, (iii) patterns, and (iv) location. Research findings show the FDI location decision process as comprising of five broad stages, the content of each driven by a dynamic and evolving interpretation of maximum subjective expected utility. Utility preferences are identified as the consequence of shifting and opaque goals, founded upon imperfect information, operating in an environment marked by uncertainty. Five variations in the overall orientation of utility at case decisions, classified in the study as ‘decision rules,’ proved to be more useful predictors of decision-making behavior than traditional notions of bounded rationality seeking rent extraction and profitability. Decision processes were found to vary in five prototypical patterns, according to clusters of contextual variables that together moderated the level of decision-maker autonomy, hierarchical centralization, rule formalization, commitment to strategy, and politicization of the decision. Patterns are described as FDI location decision-making models, and proposed as an initial step towards the development of a taxonomy of FDI location decision-making processes. Because of the dynamic and staged nature of the process, findings showed that factors that were important at one stage of the decision were not as important at the next. As such, the task of identifying universal drivers of FDI location was deemed an unfeasible one. In place of universal drivers, the initiating force of the investment, the purpose of investment and information sources and networks are identified as the key context-specific determinants of location in FDI decisions. Bounded by uncertainty, chance, the dynamics of the process and decision-maker effects, each of these aspects of the decision served to limit the possible consideration set for investment, and formed the value basis and measures from which to select the most attractive location choice. Despite the contextual differences in these drivers, however, the study revealed a strong pattern that showed that the importance of specific location considerations differed in much the same way across case decisions. During the first stage of case decisions primarily strategic aspects of locations were considered; during the second, considerations relating to the system; operational concerns in the third; implementation concerns in the fourth; and added value factors in the final choice. How each of these concerns was interpreted to reach final location choice differed according to the drivers mentioned previously, although the patterns were the same. This study develops a contingency framework for examining the FDI location decision-making processes of MNEs under different operating conditions. By identifying the four key components of the FDI location decision, their interrelationships and many sources of variance, this thesis shows that despite its complexity, the FDI location decision is amenable to useful conceptual structuring. From an academic standpoint, the framework answers Aharoni’s most recent call to action in ‘Behavioral Elements in Foreign Direct Investment’ (2010) by developing a replicable structure within which to think about incorporating managerial decision models and context into the theory of the MNE. These findings enhance understandings of decision making at MNEs, reconcile a number of inconsistencies between opposing perspectives of MNE theory, and thereby update extant theory so that it has greater relevance in today’s diverse international business environment. From a managerial standpoint, the thesis helps managers to recognize the opportunities and limitations posed by different aspects of decision context so that they are able to tailor their FDI location decision strategies to best suit their needs. Finally, from the perspective of policy markers, research findings provide great support for the use of investment attraction schemes through the use of targeted location marketing and investment incentives.

The tight junction protein CAR regulates cardiac conduction and cell–cell communication

The Coxsackievirus-adenovirus receptor (CAR) is known for its role in virus uptake and as a protein of the tight junction. It is predominantly expressed in the developing brain and heart and reinduced upon cardiac remodeling in heart disease. So far, the physiological functions of CAR in the adult heart are largely unknown. We have generated a heart-specific inducible CAR knockout (KO) and found impaired electrical conduction between atrium and ventricle that increased with progressive loss of CAR. The underlying mechanism relates to the cross talk of tight and gap junctions with altered expression and localization of connexins that affect communication between CAR KO cardiomyocytes. Our results indicate that CAR is not only relevant for virus uptake and cardiac remodeling but also has a previously unknown function in the propagation of excitation from the atrium to the ventricle that could explain the association of arrhythmia and Coxsackievirus infection of the heart

A 3D-printed anatomical pancreas and kidney phantom for optimizing SPECT/CT reconstruction settings in beta cell imaging using 111In-exendin

Contains fulltext : 165641.pdf (publisher's version ) (Open Access)BACKGROUND: Quantitative single photon emission computed tomography (SPECT) is challenging, especially for pancreatic beta cell imaging with 111In-exendin due to high uptake in the kidneys versus much lower uptake in the nearby pancreas. Therefore, we designed a three-dimensionally (3D) printed phantom representing the pancreas and kidneys to mimic the human situation in beta cell imaging. The phantom was used to assess the effect of different reconstruction settings on the quantification of the pancreas uptake for two different, commercially available software packages. METHODS: 3D-printed, hollow pancreas and kidney compartments were inserted into the National Electrical Manufacturers Association (NEMA) NU2 image quality phantom casing. These organs and the background compartment were filled with activities simulating relatively high and low pancreatic 111In-exendin uptake for, respectively, healthy humans and type 1 diabetes patients. Images were reconstructed using Siemens Flash 3D and Hermes Hybrid Recon, with varying numbers of iterations and subsets and corrections. Images were visually assessed on homogeneity and artefacts, and quantitatively by the pancreas-to-kidney activity concentration ratio. RESULTS: Phantom images were similar to clinical images and showed comparable artefacts. All corrections were required to clearly visualize the pancreas. Increased numbers of subsets and iterations improved the quantitative performance but decreased homogeneity both in the pancreas and the background. Based on the phantom analyses, the Hybrid Recon reconstruction with 6 iterations and 16 subsets was found to be most suitable for clinical use. CONCLUSIONS: This work strongly contributed to quantification of pancreatic 111In-exendin uptake. It showed how clinical images of 111In-exendin can be interpreted and enabled selection of the most appropriate protocol for clinical use

Phrenologyand the Insanity Defence: Medical Jurisprudence in the McNaughtan Trial

This thesis argues that phrenology shaped the defence argument in the McNaughtan trial. The role of this now-discredited science exemplifies the negotiation of scientific, legal and lay knowledge in the early nineteenth century, at a time when science was challenging the primacy of lay understandings of insanity. Phrenological ideas allowed the defence to privilege medical opinion over lay opinion, and propose a model of the mind that could account for McNaughtan’s insanity. This was possible because the medical and professional communities accepted some elements of the science. They applied these principles when explaining and verifying insanity in a courtroom setting

Albumin-derived peptides efficiently reduce renal uptake of radiolabelled peptides

Contains fulltext : 88022.pdf (publisher's version ) (Closed access)PURPOSE: In peptide-receptor radionuclide therapy (PRRT), the maximum activity dose that can safely be administered is limited by high renal uptake and retention of radiolabelled peptides. The kidney radiation dose can be reduced by coinfusion of agents that competitively inhibit the reabsorption of radiolabelled peptides, such as positively charged amino acids, Gelofusine, or trypsinised albumin. The aim of this study was to identify more specific and potent inhibitors of the kidney reabsorption of radiolabelled peptides, based on albumin. METHODS: Albumin was fragmented using cyanogen bromide and six albumin-derived peptides with different numbers of electric charges were selected and synthesised. The effect of albumin fragments (FRALB-C) and selected albumin-derived peptides on the internalisation of (111)In-albumin, (111)In-minigastrin, (111)In-exendin and (111)In-octreotide by megalin-expressing cells was assessed. In rats, the effect of Gelofusine and albumin-derived peptides on the renal uptake and biodistribution of (111)In-minigastrin, (111)In-exendin and (111)In-octreotide was determined. RESULTS: FRALB-C significantly reduced the uptake of all radiolabelled peptides in vitro. The albumin-derived peptides showed different potencies in reducing the uptake of (111)In-albumin, (111)In-exendin and (111)In-minigastrin in vitro. The most efficient albumin-derived peptide (peptide #6), was selected for in vivo testing. In rats, 5 mg of peptide #6 very efficiently inhibited the renal uptake of (111)In-minigastrin, by 88%. Uptake of (111)In-exendin and (111)In-octreotide was reduced by 26 and 33%, respectively. CONCLUSIONS: The albumin-derived peptide #6 efficiently inhibited the renal reabsorption of (111)In-minigastrin, (111)In-exendin and (111)In-octreotide and is a promising candidate for kidney protection in PRRT.1 februari 201

A single-cell RNA labeling strategy for measuring stress response upon tissue dissociation

Tissue dissociation, a crucial step in single-cell sample preparation, can alter the transcriptional state of a sample through the intrinsic cellular stress response. Here we demonstrate a general approach for measuring transcriptional response during sample preparation. In our method, transcripts made during dissociation are labeled for later identification upon sequencing. We found general as well as cell-type-specific dissociation response programs in zebrafish larvae, and we observed sample-to-sample variation in the dissociation response of mouse cardiomyocytes despite well-controlled experimental conditions. Finally, we showed that dissociation of the mouse hippocampus can lead to the artificial activation of microglia. In summary, our approach facilitates experimental optimization of dissociation procedures as well as computational removal of transcriptional perturbation response

Visualization of β-adrenergic receptor dynamics and differential localization in cardiomyocytes

A key question in receptor signaling is how specificity is realized, particularly when different receptors trigger the same biochemical pathway(s). A notable case is the two β‐adrenergic receptor (β‐AR) subtypes, β(1) and β(2), in cardiomyocytes. They are both coupled to stimulatory G(s) proteins, mediate an increase in cyclic adenosine monophosphate (cAMP), and stimulate cardiac contractility; however, other effects, such as changes in gene transcription leading to cardiac hypertrophy, are prominent only for β(1)‐AR but not for β(2)-AR. Here, we employ highly sensitive fluorescence spectroscopy approaches, in combination with a fluorescent β‐AR antagonist, to determine the presence and dynamics of the endogenous receptors on the outer plasma membrane as well as on the T-tubular network of intact adult cardiomyocytes. These techniques allow us to visualize that the β(2)‐AR is confined to and diffuses within the T-tubular network, as opposed to the β(1)‐AR, which is found to diffuse both on the outer plasma membrane as well as on the T-tubules. Upon overexpression of the β(2)‐AR, this compartmentalization is lost, and the receptors are also seen on the cell surface. Such receptor segregation depends on the development of the T-tubular network in adult cardiomyocytes since both the cardiomyoblast cell line H9c2 and the cardiomyocyte-differentiated human-induced pluripotent stem cells express the β(2)‐AR on the outer plasma membrane. These data support the notion that specific cell surface targeting of receptor subtypes can be the basis for distinct signaling and functional effects