Myocardial Metastases on 6-[18F] fluoro-L-DOPA PET/CT: A Retrospective Analysis of 116 Serotonin Producing Neuroendocrine Tumour Patients

Purpose

This study evaluates the prevalence of cardiac metastases in patients with serotonin producing neuroendocrine tumours (NET), examined with ¹⁸F-FDOPA PET/CT, and the relationship of these metastases to the presence of carcinoid heart disease (CHD) based on echocardiography.

Background

CHD occurs in patients with serotonin producing NET. The diagnostic method of choice remains echocardiography. The precise prevalence of cardiac metastases is unknown given the limitations of standard technologies. Nuclear medicine modalities have the potential to visualize metastases of NET.

Methods

All patients who underwent ¹⁸F-FDOPA PET/CT because of serotonin producing NET between November 2009 and May 2012 were retrospectively analyzed. The presence of cardiac metastasis was defined as myocardial tracer accumulation higher than the surrounding physiological myocardial uptake. Laboratory tests and transthoracic echocardiography (TTE) results were digitally collected.

Results

116 patients (62 male) underwent ¹⁸F-FDOPA PET/CT, mean age was 61±13 years. TTE was performed in 79 patients. Cardiac metastases were present in 15 patients, of which 10 patients also underwent TTE. One patient had both cardiac metastasis (only on ¹⁸F-FDOPA PET/CT) and echocardiographic signs of CHD. There were no differences in echocardiographic parameters for CHD between patients with and without cardiac metastases. TTE in none of the 79 patients showed cardiac metastases.

Conclusion

The prevalence of cardiac metastases detected with ¹⁸F-FDOPA PET/CT in this study is 13%. ¹⁸F-FDOPA PET/CT can visualize cardiac metastases in serotonin producing NET patients. There appears to be no relationship between the presence of cardiac metastases and TTE parameters of CHD.     

Vicissitudes of benefit sharing of crop genetic resources: downstream and upstream

In this article, we will first give a historic overview of the concept of benefit sharing and its appearance in official agreements, particularly with respect to crop genetic resources. It will become clear that, at present, benefit sharing is primarily considered as an instrument of compensation or exchange, and thus refers to commutative justice. However, we believe that such a narrow interpretation of benefit sharing disregards, and even undermines, much of its (historical) content and potency, especially where crop genetic resources are concerned. We argue that benefit sharing should not be based merely on commutative justice but rather on a broader model that is also grounded in the concept of distributive justice. This has repercussions for the application of benefit sharing, which we try to clarify by distinguishing between downstream and upstream benefit sharing. Upstream benefit sharing is not so much inspired by compensation for actions done, or the distribution downstream of benefits developed, but by the idea of shared decision-making on the research and development of resources fundamental to human welfare. Going upstream in the research process of crop genetic resources, and determining research agendas and improving crops according to the needs of the poor, benefit sharing may well be a tool to contribute to world food security and global justice. We concretize our ideas on upstream benefit sharing by introducing a set of criteria that determine the success of consultations on agricultural research agenda setting.     

Outmigration pathways of stocked juvenile European sturgeon (Acipenser sturio L., 1758) in the Lower Rhine River,as revealed by telemetry

Working towards a future Rhine Sturgeon Action Plan the outmigration pathways of stocked juvenile European sturgeon (Acipenser sturio L., 1758) were studied in the River Rhine in 2012 and 2015 using the NEDAP Trail system. A total of 87 sturgeon of 3 to 5 years old (n = 43 in 2012, n = 44 in 2015) were implanted with transponders and released in May and June in the river Rhine at the Dutch‐German border, approximately 160 km from the sea. In total three sturgeons (3%) were found dead on river banks within seven days after the release. Based upon their wounds these sturgeons were likely hit by ship‐propellers. Tracking results were obtained from 57 (66%) of the sturgeons, of which 39 (45%) indicated movement into the Port of Rotterdam. Here the sturgeons remained for an average of two weeks, which suggests they spent time to acclimatize to higher salinities before entering the North Sea. Of the 45 (52%) sturgeons that were confirmed to have entered the North Sea, ten (22%) were recaptured (mainly by shrimpers and gill‐nets) close to the Dutch coastline; nine were alive and were released. From the results we obtained the preferred outmigration pathways, movement speeds and an indication of impacting factors (i.e. ship propellers and bycatch). Bycatches provided also localisations information in the coastal area. A next step to complete this work would be to assess habitat selection in freshwater and downstream migration of young of the year (YOY sturgeons) in the Lower Rhine.     

moBeat: Using Interactive Music to Guide and Motivate Users During Aerobic Exercising

An increasing number of people are having trouble staying fit and maintaining a healthy bodyweight because of lack of physical activity. Getting people to exercise is crucial. However, many struggle with developing healthy exercising habits, due to hurdles like having to leave the house and the boring character of endurance exercising. In this paper, we report on a design project that explores the use of audio to motivate and provide feedback and guidance during exercising in a home environment. We developed moBeat, a system that provides intensity-based coaching while exercising, giving real-time feedback on training pace and intensity by means of interactive music. We conducted a within-subject comparison between our moBeat system and a commercially available heart rate watch. With moBeat, we achieved a comparable success rate: our system has a significant, positive influence on intrinsic motivation and attentional focus, but we did not see significant differences with regard to either perceived exertion or effectiveness. Although promising, future research is needed.     

Relief of hypoxia by angiogenesis promotes neural stem cell differentiation by targeting glycolysis

Blood vessels are part of the stem cell niche in the developing cerebral cortex, but their in vivo role in controlling the expansion and differentiation of neural stem cells (NSCs) in development has not been studied. Here, we report that relief of hypoxia in the developing cerebral cortex by ingrowth of blood vessels temporo‐spatially coincided with NSC differentiation. Selective perturbation of brain angiogenesis in vessel‐specific Gpr124 null embryos, which prevented the relief from hypoxia, increased NSC expansion at the expense of differentiation. Conversely, exposure to increased oxygen levels rescued NSC differentiation in Gpr124 null embryos and increased it further in WT embryos, suggesting that niche blood vessels regulate NSC differentiation at least in part by providing oxygen. Consistent herewith, hypoxia‐inducible factor (HIF)‐1α levels controlled the switch of NSC expansion to differentiation. Finally, we provide evidence that high glycolytic activity of NSCs is required to prevent their precocious differentiation in vivo. Thus, blood vessel function is required for efficient NSC differentiation in the developing cerebral cortex by providing oxygen and possibly regulating NSC metabolism.     

A process‐based metacommunity framework linking local and regional scale community ecology

The metacommunity concept has the potential to integrate local and regional dynamics within a general community ecology framework. To this end, the concept must move beyond the discrete archetypes that have largely defined it (e.g. neutral vs. species sorting) and better incorporate local scale species interactions and coexistence mechanisms. Here, we present a fundamental reconception of the framework that explicitly links local coexistence theory to the spatial processes inherent to metacommunity theory, allowing for a continuous range of competitive community dynamics. These dynamics emerge from the three underlying processes that shape ecological communities: (1) density‐independent responses to abiotic conditions, (2) density‐dependent biotic interactions and (3) dispersal. Stochasticity is incorporated in the demographic realisation of each of these processes. We formalise this framework using a simulation model that explores a wide range of competitive metacommunity dynamics by varying the strength of the underlying processes. Using this model and framework, we show how existing theories, including the traditional metacommunity archetypes, are linked by this common set of processes. We then use the model to generate new hypotheses about how the three processes combine to interactively shape diversity, functioning and stability within metacommunities.     

Tetranychus evansi spider mite populations suppress tomato defenses to varying degrees

Plant defense suppression is an offensive strategy of herbivores, in which they manipulate plant physiological processes to increase their performance. Paradoxically, defense suppression does not always benefit the defense‐suppressing herbivores, because lowered plant defenses can also enhance the performance of competing herbivores and can expose herbivores to increased predation. Suppression of plant defense may therefore entail considerable ecological costs depending on the presence of competitors and natural enemies in a community. Hence, we hypothesize that the optimal magnitude of suppression differs among locations. To investigate this, we studied defense suppression across populations of Tetranychus evansi spider mites, a herbivore from South America that is an invasive pest of solanaceous plants including cultivated tomato, Solanum lycopersicum, in other parts of the world. We measured the level of expression of defense marker genes in tomato plants after infestation with mites from eleven different T. evansi populations. These populations were chosen across a range of native (South American) and non‐native (other continents) environments and from different host plant species. We found significant variation at three out of four defense marker genes, demonstrating that T. evansi populations suppress jasmonic acid‐ and salicylic acid‐dependent plant signaling pathways to varying degrees. While we found no indication that this variation in defense suppression was explained by differences in host plant species, invasive populations tended to suppress plant defense to a smaller extent than native populations. This may reflect either the genetic lineage of T. evansi—as all invasive populations we studied belong to one linage and both native populations to another—or the absence of specialized natural enemies in invasive T. evansi populations.     

The Effect of Chemical Chaperones on the Assembly and Stability of HIV-1 Capsid Protein

Chemical chaperones are small organic molecules which accumulate in a broad range of organisms in various tissues under different stress conditions and assist in the maintenance of a correct proteostasis under denaturating environments. The effect of chemical chaperones on protein folding and aggregation has been extensively studied and is generally considered to be mediated through non-specific interactions. However, the precise mechanism of action remains elusive. Protein self-assembly is a key event in both native and pathological states, ranging from microtubules and actin filaments formation to toxic amyloids appearance in degenerative disorders, such as Alzheimer''s and Parkinson''s diseases. Another pathological event, in which protein assembly cascade is a fundamental process, is the formation of virus particles. In the late stage of the virus life cycle, capsid proteins self-assemble into highly-ordered cores, which encapsulate the viral genome, consequently protect genome integrity and mediate infectivity. In this study, we examined the effect of different groups of chemical chaperones on viral capsid assembly in vitro, focusing on HIV-1 capsid protein as a system model. We found that while polyols and sugars markedly inhibited capsid assembly, methylamines dramatically enhanced the assembly rate. Moreover, chemical chaperones that inhibited capsid core formation, also stabilized capsid structure under thermal denaturation. Correspondingly, trimethylamine N-oxide, which facilitated formation of high-order assemblies, clearly destabilized capsid structure under similar conditions. In contrast to the prevailing hypothesis suggesting that chemical chaperones affect proteins through preferential exclusion, the observed dual effects imply that different chaperones modify capsid assembly and stability through different mechanisms. Furthermore, our results indicate a correlation between the folding state of capsid to its tendency to assemble into highly-ordered structures.     

Long‐term seed bank dynamics in a temperate forest under conversion from coppice‐with‐standards to high forest management

Questions: How do changes in forest management, i.e. in disturbance type and frequency, influence species diversity, abundance and composition of the seed bank? How does the relationship between seed bank and vegetation change? What are the implications for seed bank dynamics? Location: An ancient Quercus petraea — Carpinus betulus forest in conversion from coppice‐with‐standards to regular Quercus high forest near Montargis, France. Methods: Seed bank and vegetation were sampled in six replicated stand types, forming a chronosequence along the conversion pathway. The stand types represented mid‐successional stages of stands in transition from coppice‐with‐standards (to high forest (16 plots) and early‐ and mid‐successional high forest stands (32 plots). Results: Seed bank density and species richness decreased with time since last disturbance. Adjusting for seed density effects obscured species richness differences between stand types, but species of later seres were nested subsets of earlier seres, implying concomitant shifts in species richness and composition with time since disturbance. Later seres were characterized by species with low seed weight and high seed longevity. Seed banks of early seres were more similar to vegetation than to later seres. Conclusions: Abandonment of the coppice‐with‐standards regime altered the seed bank characteristics, as well as its relationship with vegetation. Longer management cycles under high forest yield impoverished seed banks. For their persistence, seed bank species will increasingly rely on management of permanently open areas in the forest landscape. Thus, revegetation at the beginning of new high‐forest cycles may increasingly depend on inflow from seed sources.