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Purpose This study aims to define the extent of additional surgical procedures after abdominal wall closure (AWC) in patients with gastroschisis (GS) and omphalocele (OC) with special focus on gastrointestinal related operations. Methods A retrospective chart review was performed including all operations in GS and OC patients in the first year after AWC (2010–2019). The risk for surgery was calculated using the one-year cumulative incidence (CI). Results 33 GS patients (18 simple GS, 15 complex) and 24 OC patients (12 without (= OCL), 12 OC patients with liver pro-trusion (= OCL +)) were eligible for analysis. 43 secondary operations (23 in GS, 20 in OC patients) occurred after a median time of 84 days (16–824) in GS and 114.5 days (12–4368) in OC. Patients with complex versus simple GS had a significantly higher risk of undergoing a secondary operation (one-year CI 64.3% vs. 24.4%; p = 0.05). 86.5% of surgical procedures in complex GS and 36.3% in OCL + were related to gastrointestinal complications. Complex GS had a significantly higher risk for GI-related surgery than simple GS. Bowel obstruction was a risk factor for surgery in complex GS (one-year CI 35.7%). Conclusion Complex GS and OCL + patients had the highest risk of undergoing secondary operations, especially those with gastrointestinal complications
We show the existence of additive kinematic formulas for general flag area measures, which generalizes a recent result by Wannerer. Building on previous work by the second named author, we introduce an algebraic framework to compute these formulas explicitly. This is carried out in detail in the case of the incomplete flag manifold consisting of all (p+1)-planes containing a unit vector.
Exploring the in vivo subthreshold membrane activity of phasic firing in midbrain dopamine neurons
(2021)
Dopamine is a key neurotransmitter that serves several essential functions in daily behaviors such as locomotion, motivation, stimulus coding, and learning. Disrupted dopamine circuits can result in altered functions of these behaviors which can lead to motor and psychiatric symptoms and diseases. In the central nervous system, dopamine is primarily released by dopamine neurons located in the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) within the midbrain, where they signal behaviorally-relevant information to downstream structures by altering their firing patterns. Their “pacemaker” firing maintains baseline dopamine levels at projection sites, whereas phasic “burst” firing transiently elevates dopamine concentrations. Firing activity of dopamine neurons projecting to different brain regions controls the activation of distinct dopamine pathways and circuits. Therefore, characterization of how distinct firing patterns are generated in dopamine neuron populations will be necessary to further advance our understanding of dopamine circuits that encode environmental information and facilitate a behavior.
However, there is currently a large gap in the knowledge of biophysical mechanisms of phasic firing in dopamine neurons, as spontaneous burst firing is only observed in the intact brain, where access to intrinsic neuronal activity remains a challenge. So far, a series of highly-influential studies published in the 1980s by Grace and Bunney is the only available source of information on the intrinsic activity of midbrain dopamine neurons in vivo, in which sharp electrodes were used to penetrate dopamine neurons to record their intracellular activity. A novel approach is thus needed to fill in the gap. In vivo whole-cell patch-clamp method is a tool that enables access to a neuron’s intrinsic activity and subthreshold membrane potential dynamics in the intact brain. It has been used to record from neurons in superficial brain regions such as the cortex and hippocampus, and more recently in deeper regions such as the amygdala and brainstem, but has not yet been performed on midbrain dopamine neurons. Thus, the deep brain in vivo patch-clamp recording method was established in the lab in an attempt to investigate the subthreshold membrane potential dynamics of tonic and phasic firing in dopamine neurons in vivo.
The use of this method allowed the first in-depth examination of burst firing and its subthreshold membrane potential activity of in vivo midbrain dopamine neurons, which illuminated that firing activity and subthreshold membrane activity of dopamine neurons are very closely related. Furthermore, systematic characterization of subthreshold membrane patterns revealed that tonic and phasic firing patterns of in vivo dopamine neurons can be classified based on three distinct subthreshold membrane signatures: 1) tonic firing, characterized by stable, non-fluctuating subthreshold membrane potentials; 2) rebound bursting, characterized by prominent hyperpolarizations that initiate bursting; and 3) plateau bursting, characterized by transient, depolarized plateaus on which bursting terminates. The results thus demonstrated that different types of phasic firing are driven by distinct patterns of subthreshold membrane activity, which may potentially signal distinct types of information. Taken together, the deep brain in vivo patch-clamp technique can be used for the investigation of firing mechanisms of dopamine neurons in the intact brain and will help address open questions in the dopamine field, particularly regarding the biophysical mechanisms of burst firing in dopamine neurons that control behavior.
This study simulates three income tax scenarios in a Mirrleesian setting for 24 EU countries using data from the 2014 Structure of Earnings Survey. In scenario 1, each country individually maximizes its own welfare (benchmark). In scenarios 2 and 3, total welfare in the EU is maximized over a common budget constraint. Unlike scenario 2, the social planner of scenario 3 differentiates taxes by country of residence. If a common tax and transfer system were implemented in the EU, countries with a relatively higher mean wage rate—particularly those in Western and some of the Northern European countries—would transfer resources to the others. Scenario 2 implies increased labor distortions for almost all countries and, hence, leads to a contraction in total output. Scenario 3 produces higher (lower) marginal taxes for high- (low-) mean countries compared to the benchmark. The change in total output depends on the income effects on labor supply. Overall, total welfare is higher for the scenarios involving a European tax and transfer system despite more than two thirds of all the agents becoming worse off relative to the benchmark. A politically more feasible integrated tax system improves the well-being of almost half of all the EU but considerably reduces the aggregate welfare benefits.
Plastics contain a complex mixture of chemicals including polymers, additives, starting substances and side-products of processing. These plastic chemicals are prone to leach into the packaged goods, in the case of food contact materials (FCMs), or into the natural environment, in the case of plastic debris. Thus, plastics represent an exposure source of chemicals for humans and wildlife alike. While it is widely known that individual plastic chemicals, such as bisphenol A and phthalates, are hazardous, little is known on the overall chemical composition and toxicity of plastics. When fragmented into smaller particles, referred to as microplastics (< 5 mm), the plastic itself can be ingested by many species. It is well established that microplastic ingestion can have negative consequences for a wide range of organisms including invertebrates, but the contribution of plastic chemicals to the toxicity of microplastics is unclear.
Given the above, the present thesis aimed at a comprehensive toxicological, ecotoxicological and chemical characterization of everyday plastics. For a comparative evaluation, 77 plastic products were selected covering 16 material types (e.g., polyethylene) made from petroleum or renewable feedstocks. These products included biodegradable products, FCMs and non-FCMs, as well as raw materials and final products, respectively. In the first two studies, the chemical mixtures contained in the 77 products were extracted with methanol and extracts were analyzed in a set of four in vitro bioassays and by non-target high-resolution gas or liquid chromatography mass spectrometry. Since an exposure only occurs if chemicals actually leach under realistic conditions, in a third study migration experiments with water were conducted for 24 out of the 77 products. The aqueous migrates were assessed in the same way as the methanolic extracts. In addition, the freshwater invertebrate Daphnia magna was exposed chronically to microplastics made of polyvinylchloride (PVC), polyurethane (PUR) and polylactic acid (PLA) to investigate the contribution of chemicals in microplastic toxicity, in a fourth study.
The experimental findings demonstrate that a wide variety of chemicals is present in plastics. A single plastic product can contain up to several thousand chemical features, most of which unique to that product and at the same time unknown. The results also indicate that the majority of these chemical mixtures are toxic in vitro. Accordingly, 65% of the plastic extracts induced baseline toxicity and 42% an oxidative stress response, while 25% had an antiandrogenic and 6% an estrogenic activity. This implies that chemicals causing unspecific toxicity are more prevalent in plastics than such with endocrine effects. These chemicals can also leach from plastics under realistic conditions. Between 17 and 8936 chemical features were detected in a single migrate sample and all 24 tested migrates induced in vitro toxicity. This means that humans and wildlife can actually be exposed to toxic plastic chemicals under realistic conditions. Generally, each product has its individual toxicological and chemical fingerprint. Thus, neither material type, feedstock, biodegradability nor the food contact suitability of a product can serve as a predictor for the toxicity, the chemical composition or complexity of a product. Likewise, this means that bio-based and biodegradable materials are not superior to their petroleum-based counterparts from a toxicological perspective despite being promoted as sustainable alternatives to conventional plastics.
Moreover, the present thesis demonstrates that plastic chemicals can be the main driver for microplastic toxicity. Irregular microplastics made of PVC, PUR and PLA adversely affected life-history traits of D. magna in a polymer type- and endpoint-dependent manner at concentrations between 100 and 500 mg L-1 and with a higher efficiency than natural kaolin particles. While the toxicity of PVC was triggered by the chemicals used in the material, the effects of PUR and PLA were induced by the physical properties of the particle.
In addition, in the fifth study, results and observations made during this thesis were integrated inter- and transdisciplinarily with the perspectives of a social scientist and a product manufacturer. This elucidated that knowledge on plastic ingredients is often concealed, is lacking or not applicable in practice. These intransparencies hinder the safety evaluation of plastic products as well as the choice and sale of the least toxic packaging material.
Overall, the present thesis highlights that the chemical safety of plastics and their bio-based and biodegradable alternatives is currently not ensured. Thus, chemicals require more consideration in the toxicity and risk assessment of plastics and microplastics. Product-specific and complex chemical compositions, including unknown compounds, pose a challenge here. Two essential steps towards non-toxic products are to increase transparency along the product life cycle and to reduce the chemical complexity of plastics by communication and regulation. The results of the present thesis indicate that products exist which do not contain toxic chemicals. These can serve to direct the design of safer plastics. Since toxicity and chemical complexity seem to increase with processing, the integration of toxicity testing during the production steps would further support the safe and sustainable production and use of plastic products.
Sympathetic influences on articular cartilage regeneration capacity and osteoarthritis manifestation
(2021)
The pathogenesis of osteoarthritis (OA) involves articular cartilage, synovial tissue and subchondral bone and is therefore a disease of the whole joint. OA is characterized by progressive degradation of cartilage, synovial inflammation, osteophyte formation and subchondral bone sclerosis. Cartilage-surrounding tissues are innervated by tyrosine hydroxylase (TH)-positive sympathetic nerve fibers with the most important sympathetic neurotransmitter norepinephrine (NE) detected in the synovial fluid of OA patients. Furthermore, adrenergic receptors are expressed in different knee joint tissues. Most in vitro studies indicate a potential role of the β2-adrenergic receptor, which has been not investigated during OA pathogenesis in vivo. The role of the sympathetic nervous system (SNS) in OA progression has not yet been studied. Therefore, the objective of this study was to analyze how the SNS and NE influence the MSC dependent cartilage regeneration in vitro and the OA pathogenesis and manifestation in vivo.
In the first part of this study, the effect of NE on the chondrogenesis of sASC, which are known to play an important role in cartilage regeneration was analyzed in vitro. In the second part of this study, the role of the SNS was studied in vivo in mice that were sympathectomized chemically followed by surgically induced OA. The specific focus was on the β2-adrenergic receptor effects on OA pathogenesis, which were analyzed in β2-adrenergic receptor-deficient mice.
The in vitro experiments have shown that NE reduced the chondrogenic potential of sASCs by decreasing the expression of type II collagen and sGAG. NE mediated these effects mainly by the α2-AR signalling. Furthermore, NE treatment led to activation of the ERK1/2 signal pathway. These findings suggested that the sympathetic neurotransmitter NE might suppress the chondrogenic capacity of MSC and their dependent cartilage regeneration and may also play a role in OA progression and manifestation.
The in vivo study has shown that sympathectomy reduced synovial TH-positive nerve fibers in the synovium and the NE concentration in the spleen significantly. In WT mice, DMM leads to increased NE concentrations in the spleen compared to sham mice indicating an increased SNS activity after mechanical stress or inflammation due to DMM. Sympathectomy leads to less pronounced cartilage degeneration (OARSI score) after DMM compared to DMM in WT mice. Furthermore, the release of the type II collagen degradation fragment CTX-II was abolished in Syx DMM mice compared to WT DMM mice, suggesting that less SNS activity due to sympathectomy reduced the cartilage degeneration during OA pathogenesis. Similarly, sympathectomy decreased the synovitis score significantly after DMM compared to DMM in
WT mice. Synovitis in WT mice was accompanied by increased MMP-13 expression in the synovium after DMM, compared to Syx mice. Cartilage degeneration seemed to be driven mainly by the increased synovial inflammation accompanied by an increased MMP13 expression in synoviocytes and not in chondrocytes. The pathological changes in synovium and cartilage might also be linked to each other, as indicated by the moderate correlation between the synovial inflammation (synovitis score) and cartilage degeneration (OARSI score). Subchondral bone volume as well the thickness of the subchondral bone plate (SCBP) and calcified cartilage (CC) were increased in Syx mice compared to WT after DMM. The data on DMM induction in β2-AR deficient mice revealed that the β2-AR signaling is involved in cartilage degeneration and the aggravated subchondral bone changes as these mice had less pronounced cartilage degeneration compared to WT mice. While the cartilage degeneration was similar, the subchondral bone changes were more pronounced in β2-AR deficient mice compared to the Syx mice.
Overall, the SNS had differential effects in cartilage, synovium and subchondral bone. A reduced SNS activity by sympathectomy attenuated cartilage degeneration and synovitis but aggravated the OA specific subchondral bone changes. These findings provide new insights into the development of novel therapeutic strategies for OA by targeting the SNS in a tissue- specific manner.
This paper was presented at the workshop “Goods, Languages, and Cultures along the Silk Road” at Goethe University Frankfurt am Main, October 18 and 19, 2019. While many contributions to the workshop focused on recent developments in China’s current “New Silk Road” politics, on forms of communication, and on contemporary exchange of goods and ideas across so-called Silk Road countries in the Caucasus and Central Asia and with China, this short essay focuses on the history of the so-called Silk Road as an important transport connection. Although what is now called the “Silk Road” was not a pure East-West binary in antiquity but rather developed into a network that also led to the South and North, the focus here will be on describing the East-West connection.
I will start with a few brief remarks on the origins of the connection referred to as the Silk Road and will then introduce the different great empires that shaped this connection between antiquity and the Middle Ages through military campaigns and by using it as a trading route and network. But the Silk Road was by no means only of economic and military importance. Its significance for the exchange and dissemination of religions should also be mentioned. This paper does not detail the importance of the numerous individual religions in the area of the Silk Road but discusses the phenomenon of the spread of religions and the loss of some of their own distinguishing characteristics in this spread, a phenomenon that could be described as a “unity of opposites” (coincidentia oppositorum). Finally, the essay asks who, in the face of the regular replacement of powers, held sovereignty over the transport connection: the subject (in the form of the empires) or the object (in the form of the road).
Who were the main protagonists of and along the Silk Road in the course of history? Who were the people who became the great powers of the ancient Silk Road, building up the material route, governing parts of it, and organizing trade and relationships from the far East to the extreme West of the Eurasian continent?
The merchant language of the Georgian Jews deserves scholarly attention for several reasons. The political and social developments of the last fifty years have caused the extinction of this very interesting form of communication, as most Georgian Jews have emigrated to Israel. In a natural interaction, the type of language described in this article can be found very rarely, if at all. Records of this communication have been preserved in various contexts and received different levels of scholarly attention. Our interest concerns the linguistic aspects as well as the classification.
In the following paper we argue that the specific merchant language of Georgian Jews belongs to the pragmatic phenomenon of “very indirect language.” The use of mostly Hebrew lexemes in Georgian conversation leads to an unfounded assumption that the speakers are equally competent in Hebrew and Georgian. It is reported that a high level of linguistic competence in Hebrew does not guarantee understanding of the Jewish merchant language. In the Georgian context, the decisive factors are membership in the professional interest group of merchants and residential membership in the Jewish community. These factors seem to be equivalent, because Jewish members of other professional groups (and those from outside the particular urban residential area) have difficulties in following the language that are similar to those of the Georgian majority. We describe the pragmatic structure of interactions conducted with the help of the merchant language and take into account the purpose of the language’s use or the intention of the speakers. Relevant linguistic examples are analysed and their sociocultural contexts explained.