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Search Results: 1 - 10 of 297369 matches for " Jürgen Meixensberger "
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Surgical Treatment for Neonatal Hydrocephalus: Catheter-Based Cerebrospinal Fluid Diversion or Endoscopic Intervention?  [PDF]
Matthias Krause, Christos P. Panteliadis, Christian Hagel, Franz W. Hirsch, Ulrich H. Thome, Jürgen Meixensberger, Ulf Nestler
Open Journal of Modern Neurosurgery (OJMN) , 2018, DOI: 10.4236/ojmn.2018.81002
Abstract: Neonatal hydrocephalus can arise from a multitude of disturbances, among them congenital aqueductal stenosis, myelomeningocele or posthemorrhagic complications in preterm infants. Diagnostic work-up comprises transfontanellar ultrasonography, T2 weighted MRI and clinical assessment for rare inherited syndromes. Classification of hydrocephalus and treatment guidelines is based on detailed consensus statements. The recent evidence favors catheter-based cerebrospinal fluid diversion in children below 6 months, but emerging techniques such as neuroendoscopic lavage carry the potential to lower shunt insertion rates. More long-term study results will be needed to allow for individualized, multidisciplinary decision making. This article gives an overview regarding contemporary pathophysiological concepts, the latest consensus statements and most recent technical developments.
Giant intradiploic epidermoid cyst with large osteolytic lesions of the skull: a case report
Wolfgang Krupp, Alexander Heckert, Heidrun Holland, Jürgen Meixensberger, Dominik Fritzsch
Journal of Medical Case Reports , 2012, DOI: 10.1186/1752-1947-6-85
Abstract: An 81-year-old Caucasian man, who had first noticed a painless subcutaneous swelling over the left frontal scalp about 40 years ago, presented after a short episode of dizziness, which he experienced after treatment of focal retinal detachment. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations revealed an exceptionally large tumor involving major parts of the skull with extensive destruction of the bone and distinct deformation of the brain. Considering his age and the absence of neurological deficits or pain, the patient refused the option of tumor removal and cranioplasty, yet agreed to a biopsy, which confirmed the suspected diagnosis.The course of the disease demonstrates that even patients with large tumors, inducing distinct pathomorphological changes, do not necessarily experience significant impairment of their quality of life without surgery. This is an impressive example of the chance to lead a long and satisfying life without specific medical treatment, avoiding the inherent risks of these procedures. Yet, there is a clear indication for surgery of intradiploic epidermoids in most cases described in the literature.We report the case of a patient with a progressive swelling of the cranial vault and growing lesions of the skull who refused any further diagnostic procedures over a period of 40 years, although it was urgently recommended by his physicians. When he finally agreed to undergo a magnetic resonance imaging (MRI) investigation, large polycystic calvarial defects and extensive deformation of major parts of the brain were detected.The patient had an exceptionally large intradiploic epidermoid cyst with extensive destruction of large areas of the skull and distinct deformations of the brain without neurological deficits.Cranial epidermoid cysts are rare lesions, representing between 0.2% and 1% of all intracranial tumors. Intradiploic epdermoid cysts account for about 25% of these lesions [1-3]. Most of them are slow growing,
Fluorescent Protein-Expressing Neural Progenitor Cells as a Tool for Transplantation Studies
Marco Skardelly, Eileen Hempel, Johannes Hirrlinger, Florian Wegner, Jürgen Meixensberger, Javorina Milosevic
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0099819
Abstract: The purpose of this study was to generate quadruple fluorescent protein (QFP) transgenic mice as a source for QFP-expressing neural stem and progenitor cells (NSCs/NPCs) that could be utilized as a tool for transplantation research. When undifferentiated, these NSCs only express cyan fluorescent protein (CFP); however, upon neuronal differentiation, the cells express yellow fluorescent protein (YFP). During astrocytic differentiation, the cells express green fluorescent protein (GFP), and during oligodendrocytic differentiation, the cells express red fluorescent protein (DsRed). Using immunocytochemistry, immunoblotting, flow cytometry and electrophysiology, quadruple transgenic NPCs (Q-NPCs) and GFP-sorted NPCs were comprehensively characterized in vitro. Overall, the various transgenes did not significantly affect proliferation and differentiation of transgenic NPCs in comparison to wild-type NPCs. In contrast to a strong CFP and GFP expression in vitro, NPCs did not express YFP and dsRed either during proliferation or after differentiation in vitro. GFP-positive sorted NPCs, expressing GFP under the control of the human GFAP promoter, demonstrated a significant improvement in astroglial differentiation in comparison to GFP-negative sorted NPCs. In contrast to non-sorted and GFP-positive sorted NPCs, GFP-negative sorted NPCs demonstrated a high proportion of neuronal differentiation and proved to be functional in vitro. At 6 weeks after the intracerebroventricular transplantation of Q-NPCs into neonatal wild-type mice, CFP/DCX (doublecortin) double-positive transplanted cells were observed. The Q-NPCs did not express any other fluorescent proteins and did not mature into neuronal or glial cells. Although this model failed to visualize NPC differentiation in vivo, we determined that activation of the NPC glial fibrillary acid protein (GFAP) promoter, as indicated by GFP expression, can be used to separate neuronal and glial progenitors as a valuable tool for transplantation studies.
Carnosine retards tumor growth in vivo in an NIH3T3-HER2/neu mouse model
Christof Renner, Nadine Zemitzsch, Beate Fuchs, Kathrin D Geiger, Matthias Hermes, Jan Hengstler, Rolf Gebhardt, Jürgen Meixensberger, Frank Gaunitz
Molecular Cancer , 2010, DOI: 10.1186/1476-4598-9-2
Abstract: A mouse model was used to investigate whether tumor growth in vivo can be inhibited by carnosine. Therefore, NIH3T3 fibroblasts, conditionally expressing the human epidermal growth factor receptor 2 (HER2/neu), were implanted into the dorsal skin of nude mice, and tumor growth in treated animals was compared to control mice. In two independent experiments nude mice that received tumor cells received a daily intra peritoneal injection of 500 μl of 1 M carnosine solution. Measurable tumors were detected 12 days after injection. Aggressive tumor growth in control animals, that received a daily intra peritoneal injection of NaCl solution started at day 16 whereas aggressive growth in mice treated with carnosine was delayed, starting around day 19. A significant effect of carnosine on tumor growth was observed up to day 24. Although carnosine was not able to completely prevent tumor growth, a microscopic examination of tumors revealed that those from carnosine treated animals had a significant lower number of mitosis (p < 0.0003) than untreated animals, confirming that carnosine affects proliferation in vivo.As a naturally occurring substance with a high potential to inhibit growth of malignant cells in vivo, carnosine should be considered as a potential anti-cancer drug. Further experiments should be performed in order to understand how carnosine acts at the molecular level.Carnosine, a dipeptide discovered more than 100 years ago [1] is a naturally occurring substance synthesized by endogenous carnosine synthetase. It is present in mammalian brain at a concentration between 0.7 and 2.0 mM [2] and reaches concentrations of up to 20 mM in skeletal muscle [3]. However, not much is known about its physiological function but several possible roles have been considered since its first discovery (for detailed review see [4,5]). Among these functions ph-buffering [6], metal chelation [7] or neurotransmitter function [8] have been discussed and the currently most intensively de
Inpatient or Outpatient Rehabilitation after Herniated Disc Surgery? – Setting-Specific Preferences, Participation and Outcome of Rehabilitation
Margrit L?bner, Melanie Luppa, Alexander Konnopka, Hans J. Meisel, Lutz Günther, Jürgen Meixensberger, Katarina Stengler, Matthias C. Angermeyer, Hans-Helmut K?nig, Steffi G. Riedel-Heller
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0089200
Abstract: Objective To examine rehabilitation preferences, participation and determinants for the choice of a certain rehabilitation setting (inpatient vs. outpatient) and setting-specific rehabilitation outcomes. Methods The longitudinal observational study referred to 534 consecutive disc surgery patients (18–55 years). Face-to-face baseline interviews took place about 3.6 days after disc surgery during acute hospital stay. 486 patients also participated in a follow-up interview via telephone three months later (dropout-rate: 9%). The following instruments were used: depression and anxiety (Hospital Anxiety and Depression Scale), pain intensity (numeric analog scale), health-related quality of life (Short Form 36 Health Survey), subjective prognosis of gainful employment (SPE-scale) as well as questions on rehabilitation attendance, return to work, and amount of sick leave days. Results The vast majority of patients undergoing surgery for a herniated disc attended a post-hospital rehabilitation treatment program (93%). Thereby two-thirds of these patients took part in an inpatient rehabilitation program (67.9%). Physical, psychological, vocational and health-related quality of life characteristics differed widely before as well as after rehabilitation depending on the setting. Inpatient rehabilitees were significantly older, reported more pain, worse physical quality of life, more anxiety and depression and a worse subjective prognosis of gainful employment before rehabilitation. Pre-rehabilitation differences remained significant after rehabilitation. More than half of the outpatient rehabilitees (56%) compared to only one third of the inpatient rehabilitees (33%) returned to work three months after disc surgery (p<.001). Conclusion The results suggest a “pre-selection” of patients with better health status in outpatient rehabilitation. Gaining better knowledge about setting-specific selection processes may help optimizing rehabilitation allocation procedures and improve rehabilitation effects such as return to work.
Operator Splitting Method for Coupled Problems:Transport and Maxwell Equations  [PDF]
Jürgen Geiser
American Journal of Computational Mathematics (AJCM) , 2011, DOI: 10.4236/ajcm.2011.13019
Abstract: In this article a new approach is considered for implementing operator splitting methods for transport problems, influenced by electric fields. Our motivation came to model PE-CVD (plasma-enhanced chemical vapor deposition) processes, means the flow of species to a gas-phase, which are influenced by an electric field. Such a field we can model by wave equations. The main contributions are to improve the standard discretization schemes of each part of the coupling equation. So we discuss an improvement with implicit Runge- Kutta methods instead of the Yee’s algorithm. Further we balance the solver method between the Maxwell and Transport equation.
Development of a computer vision system to monitor pig locomotion  [PDF]
Jrgen Kongsro
Open Journal of Animal Sciences (OJAS) , 2013, DOI: 10.4236/ojas.2013.33038
Abstract: Avoiding lameness or leg weakness in pig production is crucial to reduce cost, improve animal welfare and meat quality. Detection of lameness detection by the use of vision systems may assist the farmer or breeder to obtain a more accurate and robust measurement of lameness. The paper presents a low-cost vision system for measuring the locomotion of moving pigs based on motion detection, frame-grabbing and multivariate image analysis. The first step is to set up a video system based on web camera technology and choose a test area. Secondly, a motion detection and data storage system are used to build a processing system of video data. The video data are analyzed measuring the properties of each image, stacking them for each animal and then analyze these stacks using multivariate image analysis. The system was able to obtain and decompose information from these stacks, where components could be extracted, representing a particular motion pattern. These components could be used to classify or score animals according to this pattern, which might be an indicator of lameness. However, further improvement is needed with respect to standardization of herding, test area and tracking of animals in order to have a robust system to be used in a farm environment.
The Motley World of “International Values”: Modes of Production on the World Market  [PDF]
Jrgen Sandemose
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.63058
Abstract: I venture to describe the world market from the viewpoint of those different extant modes of production which deliver commodities in “foreign” trade. The world market is, then, understood strictly in its basic feature, as a market for material products, all called commodities. The term “exchange”, which has to be used with some indeterminacy to begin with, is explained in greater detail as I proceed. In this regard, the most important sections are nos. 2 and 3. The term “modes of production” will also be clarified in due place, and primarily in Sections 9 and 10. I find such a concept necessary for an adequate background description of the products which are poured onto any market. I primarily analyze the capitalist mode of production through the concept of intensity of labour (cf. 4 and 9), which plays a main role even in Marx’s theory of the “modifications” of the law of value on the world market. Also, I find what is often labelled “Karl Marx’s theory of international values” to be correct in its foundations, and I will take a point of departure in it—especially apparent in sections 1, 2 and 3. A target for criticism in this article is the modern mainstream theory of “factors of production” in so far as it is found feasible for an analysis of the movements on the world market. This is briefly done in Section 8. In Section 6, I consider David Ricardo’s theory of “comparative advantages” as a counter-example to that theory. I use some terrain to show that the real historical and social background of the economic functioning of the so-called “factors”—capital, land and labour—must be a measuring rod for whether a factor theory is viable or not. To do this, I depend (cf. again Sections 9 and 10) to a high degree of Marx’s theory of those factors considered as forms of organized class forces—a viewpoint which played a central role in his preparing of the three volumes of Capital. While the Marxian theory insofar is adequate, it is also useful in analyzing the aborted or undeveloped state of those modes of production which, beneath the advanced capitalist one, supply the world market with material products. This ought to become clear especially in Sections 10 and 11. As my text expands, I try to show how the said inconsistency in the Ricardian model is based on
On the Exposition of the Transformation of Commodity-Values into Production Prices in the Third Volume of Capital—A Textual Analysis  [PDF]
Jrgen Sandemose
Theoretical Economics Letters (TEL) , 2016, DOI: 10.4236/tel.2016.65098
Abstract: The article is about the exposition of the Karl Marx’s concept of production prices in his main work Capital. It focuses on the structure of the central text in question, Chapter 9 of the third volume, on “transformation [Verwandlung] of commodity-values into production prices”. The actual content and structure of the chapter has to some degree been overlooked or distorted in the literature. The aim of the article is to establish (or re-establish) a sound view of the chapter, freed from prejudices nurtured by—especially—a theory of price formation which, albeit “modernized” by i.a. Walras, dates back to Steuart and Ricardo. These prejudices have had an immense significance for misunderstandings of the Marxian theory of measure of value and standard of prices reflected in the text of the chapter mentioned. For this reason, the article is furnished with an Appendix, underlining the difficult situation for Marxist-minded research today. It should be noted that it is not an objective of the article to discuss any extant interpretation of Marx’s exposition. However, the paradigm of criticism that was introduced early in the 20th century by Ladislaus von Bortkiewicz is used as a perspective. Specific references—other than to Marx’s own texts—are held at a minimum in the article proper. I have chosen such a mode of approach because I find that misunderstandings of the chapter are evenly distributed among authors regardless of how their views on the “transformation” collide. On the other hand, such a consciousness of “misunderstandings” among commentators certainly does imply that the author should at least shortly clarify his own view of the main problems in the paradigmatic criticism mentioned above. In the first section, I point out the importance of Marx’s way of presenting his concept of the composition of capital. In the next, I make some remarks on the concept of the socially necessary labour time and its relation to abstract labour. In the third and fourth, I investigate Marx’s different models of analysis. In the fifth section, it will be shown how Marx, contrary to
Paradoxes, Self-Referentiality, and Hybrid Systems: A Constructive Approach  [PDF]
Jürgen Klüver
Open Journal of Philosophy (OJPP) , 2017, DOI: 10.4236/ojpp.2017.71004
Abstract:
Since the discovery of the paradoxes of self-referentiality or self-reference respectively logicians and mathematicians tried to avoid self-reference when constructing formal systems. Yet “real” complex systems like the mind are characterized by self-reference and can accordingly only be modeled by formal systems that are also basically self-referential. In this article I show that and how self-referential computer programs, understood as algorithmic formal systems, are not only possible but also since some time quite common in special branches of computer science. Examples for this argument are neural networks and so-called hybrid systems, i.e. combination of different sub systems. The hybrid system SOCAIN, a combination of a cellular automaton, a neural network and a genetic algorithm is an example for the fruitfulness of using self-reference in a systematic way. In particular, such systems consist of mutually dependent sub systems, i.e. form no static hierarchy.
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