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Search Results: 1 - 10 of 22396 matches for " Hans-Christian Siebert "
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In silico Study on Sulfated and Non-Sulfated Carbohydrate Chains from Proteoglycans in Cnidaria and Interaction with Collagen  [PDF]
Thomas Eckert, Sabine St?tzel, Monika Burg-Roderfeld, Judith Sewing, Thomas Lütteke, Nikolay E. Nifantiev, Johannes F. G. Vliegenthart, Hans-Christian Siebert
Open Journal of Physical Chemistry (OJPC) , 2012, DOI: 10.4236/ojpc.2012.22017
Abstract: Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of maturation. Tissues from Cnidaria are suitable examples for exploration of the effects in relation to the presence and the absence of sulfate groups, when studying characteristic fragments of the long proteoglycan carbohydrate chains in silico. It has been described that a non-sulfated chondroitin appears as a scaffold in early morphogenesis of all nematocyst types in Hydra. On the other hand, sulfated glucosaminoglycans play an important role in various developmental processes of Cnidaria. In order to understand this biological phenomenon on a sub-molecular level we have analysed the structures of sulfated and non-sulfated proteoglycan carbohydrate chains as well as the structure of diverse collagen molecules with computational methods including quantum chemical calculations. The strong interactions between the sulfate groups of the carbohydrates moieties in proteoglycans and positively charged regions of collagen are essential in stabilizing various Cnidaria tissues but could hinder the nematocyst formation and its proper function. The results of our quantum chemical calculations show that the sulfation pattern has a significant effect on the conformation of chondroitin structures under study.
Collagen Metabolism of Human Osteoarthritic Articular Cartilage as Modulated by Bovine Collagen Hydrolysates
Saskia Schadow, Hans-Christian Siebert, Günter Lochnit, Jens Kordelle, Markus Rickert, Jürgen Steinmeyer
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053955
Abstract: Destruction of articular cartilage is a characteristic feature of osteoarthritis (OA). Collagen hydrolysates are mixtures of collagen peptides and have gained huge public attention as nutriceuticals used for prophylaxis of OA. Here, we evaluated for the first time whether different bovine collagen hydrolysate preparations indeed modulate the metabolism of collagen and proteoglycans from human OA cartilage explants and determined the chemical composition of oligopeptides representing collagen fragments. Using biophysical techniques, like MALDI-TOF-MS, AFM, and NMR, the molecular weight distribution and aggregation behavior of collagen hydrolysates from bovine origin (CH-Alpha?, Peptan? B 5000, Peptan? B 2000) were determined. To investigate the metabolism of human femoral OA cartilage, explants were obtained during knee replacement surgery. Collagen synthesis of explants as modulated by 0–10 mg/ml collagen hydrolysates was determined using a novel dual radiolabeling procedure. Proteoglycans, NO, PGE2, MMP-1, -3, -13, TIMP-1, collagen type II, and cell viability were determined in explant cultures. Groups of data were analyzed using ANOVA and the Friedman test (n = 5–12). The significance was set to p≤0.05. We found that collagen hydrolysates obtained from different sources varied with respect to the width of molecular weight distribution, average molecular weight, and aggregation behavior. None of the collagen hydrolysates tested stimulated the biosynthesis of collagen. Peptan? B 5000 elevated NO and PGE2 levels significantly but had no effect on collagen or proteoglycan loss. All collagen hydrolysates tested proved not to be cytotoxic. Together, our data demonstrate for the first time that various collagen hydrolysates differ with respect to their chemical composition of collagen fragments as well as by their pharmacological efficacy on human chondrocytes. Our study underscores the importance that each collagen hydrolysate preparation should first demonstrate its pharmacological potential both in vitro and in vivo before being used for both regenerative medicine and prophylaxis of OA.
Towards a new strategy to implement psychosomatic knowledge in medical practice
Hans-Christian Deter
BioPsychoSocial Medicine , 2008, DOI: 10.1186/1751-0759-2-1
Abstract: As we better understand the mechanisms of the development in these diseases. especially the psychosocial influences, each country needs to develop a strategy to implement this knowledge into its practice of medicine.The conditions of the health care system in Germany differ from those of France and Japan. Thus, it seems necessary to promote psychosomatic knowledge – conducting convincing psychosomatic studies in different medical fields – in the national health care system and in society. To implement this it is necessary to have cooperation between workers in government, in faculties/universities and in medical associations. However, the basis is holistic thinking about mind and body in the society. Japanese culture is in accord with holistic thinking in Europe and with the ideas of psychosomatic theory and practice in Germany. Victor von Weizs?cker and Thure von Uexküll in Germany and Yujiro Ikemi in Japan attempted to bring psychosomatic thinking into clinical practice as an advantage for all patients.The differences between these earlier times and today in psychosomatic research are that, (1) we need good data in all medical fields to demonstrate psychosomatic interactions in different diseases, (2) we need to show that special psychosomatic strategies of treatment are useful for special psychological, biological and social targets in these diseases, and (3) to demonstrate in randomized psychosomatic clinical trials that treatment effects are comparable to other, more usual, treatments (TAU). Only in this way is it possible to bring psychosomatic experiences and knowledge into the national and international guidelines for special diseases, as have the European guidelines for prevention of coronary heart diseases (Orth-Gomer et al. 2005) [1].This is a program in many national and international psychosomatic research centres and will be supported by the national psychosomatic societies. The communication and integration of these ongoing studies in journals such as
Psychosocial interventions for patients with chronic disease
Hans-Christian Deter
BioPsychoSocial Medicine , 2012, DOI: 10.1186/1751-0759-6-2
Abstract: In a psychosomatic therapeutic intervention there are very different targets, such as psychological symptoms, personality traits, attitudes toward disease and life, risk behaviour, and social isolation and as biological targets the change of autonomic imbalance and of the effects of the psycho-endocrinological or psycho-immunological stress responses. And there are also different psychosomatic measures that influence the individual biological, psychological and sociological targets. There is a need to give different answer to different questions in the field of psychosomatic and behavioral medicine. Comparative effectiveness research is an important strategy for solving some methodological issues. What is the target of treatment for different diseases: Symptom reduction, healing, or limiting progression to the worst case - the death of patients. We know that, the patient-physician relationship is important for every medical/therapeutic action for patients with chronic diseases.This volume of BioPsychoSocial Medicine will present four different psychosomatic treatment studies from the clinical field in the sense of phase 2 studies: Reports of patients with obesity, anorexia nervosa, chronic somatoform pain and coronary artery disease were presentedBio psycho social medicine integrates different levels of research: The basic sciences focus on psychobiological mechanisms (e.g. psycho-neuroendocrinology, psycho-neuroimmunology, psycho-physiology) and psycho-somatic correlations. Various pathways have been formulated for different chronic diseases as have strategies for research on interactions between psychic phenomenon and biological functions found in different regions of the body, such as the brain-gut axis and the brain-heart axis. Medicine is not only a diagnostic discipline, but also a research field for medical practice - concentrating on physicians and other health care workers in action with their patients and focusing on the transfer of psychosomatic knowledge
Das preu ische Kultusministerium und die
Hans-Christian Jasch
Forum Historiae Iuris , 2005,
Abstract:
Forskning i tegneserier
Hans-Christian Christiansen
MedieKultur : Journal of Media and Communication Research , 1999,
Abstract: Der har altid eksisteret akademisk mistro over for massekultur. Som en f lge heraf har der v ret en tendens i forskningen til kun at betragte fel- tets modtagereffekt eller indskrive f nomenet i pessimistiske kulturbe- skrivelser: Den tidlige forskning i tegneserien har s ledes i h j grad v ret pr get af opremsninger af negative effekter, og indtil 60'erne var forskningsfeltet karakteriseret ved et meget begr nset analytisk per- spektiv. I slutningen af 60'erne blev tegneserien imidlertid ”opdaget” af litteraturteorien, der is r betonede tegneseriens sociologiske og ideolo- giske aspekter, og tillige blev tegneserien i 60'erne genstand for semio- tisk funderet analyse i k lvandet p en voksende interesse for masse- kultur. Med denne interesse for massekultur og en begyndende kulturel institutionalisering af tegneserien i Frankrig og Belgien tegnede der sig efterh nden konturerne af en tegneserieteori.
Solving Gauge Field Theory by Discretized Light-Cone Quantization
Hans-Christian Pauli
Physics , 1996,
Abstract: The canonical front form Hamiltonian for non-Abelian SU(N) gauge theory in 3+1 dimensions is mapped on an effective Hamiltonian which acts only in the Fock space of one quark and one antiquark. The approach is non-perturbative and exact. It is based on Discretized Light-Cone Quantization and the Method of Iterated Resolvents. The method resums the diagrams of perturbation theory to all orders in the coupling constant and is free of Tamm-Dancoff truncations in the Fock-space. Emphasis is put on dealing accurately with the many-body aspects of gauge field theory. Pending future renormalization group analysis the running coupling is derived to all orders in the bare coupling constant.~--- The derived effective interaction has an amazingly simple structure and is gauge invariant and frame independent. It is solvable on a small computer like a work station. The many-body amplitudes can be retrieved self-consistently from these solutions, by quadratures without solving another eigenvalue problem. The structures found allow also for developing simple phenomenological models consistent with non-Abelian gauge field theory.
On the effective light-cone QCD-Hamiltonian
Hans-Christian Pauli
Physics , 2000,
Abstract: Taking the effective interaction between a quark and an anti-quark from previous work, the dependendence on a regularization scale is removed in line with the renormalization group. In order to emphasize the essential point, the full spinor interaction is replaced by a model which includes only the Coulomb and the hyperfine interaction. By adjusting the effective quark masses, the only free parameters of the theory, the mass and the size of the pion are reproduced, as well as the mass of all other pseudo-scalar mesons. Estimates for the vector mesons are close to the empirical values. The model exposes screening rather than strict confinement. The ionization thresholds are in general much larger than the pion mass.
Applying the flow equations to QCD
Hans-Christian Pauli
Physics , 2001, DOI: 10.1016/S0920-5632(00)00912-9
Abstract: The effective quark-antiquark-interaction is derived from Lagrangian QCD in the front form by means of the flow equations. It coincides with previous results.
Estimates of the physical meson masses by an effective light-cone Hamiltonian
Hans-Christian Pauli
Physics , 2001,
Abstract: A recent renormalization group analysis of the effective light-cone Hamiltonian yields 5 flavor masses and 2 mass shifts as free parameters. These are determined in the present note and used to calculate the masses of all 30 physical mesons (The topped mesons have been omitted). The agreement between experiment and theoretical estimate is quite satisfactory over the whole dynamical range, from the lightest pseudo-scalar mesons like the pion up to the heaviest vector mesons like the upsilon. Evidence for an additive quark model is given and for how the concept of isospin is realized in a gauge field theory such as QCD.
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