Showing papers by "Martin Luther University of Halle-Wittenberg published in 1997"
TL;DR: The cachectic state was predictive of 18-month mortality independent of age, NYHA class, left-ventricular ejection fraction, and peak oxygen consumption, and a subset of patients at extremely high risk of death was identified.
1,279 citations
07 Jul 1997
TL;DR: An overview of the LEDA platform for combinatorial and geometric computing and an account of its development are given and some recent theoretical developments are discussed.
Abstract: We give an overview of the LEDA platform for combinatorial and geometric computing and an account of its development. We discuss our motivation for building LEDA and to what extent we have reached our goals. We also discuss some recent theoretical developments. This paper contains no new technical material. It is intended as a guide to existing publications about the system. We refer the reader also to our web-pages for more information.
473 citations
TL;DR: In patients with chronic HF, quadriceps maximal isometric strength is reduced and muscular atrophy becomes a major determinant of exercise capacity and is an independent predictor of peak absolute VO2.
383 citations
TL;DR: In this paper, the van der Waals glass salol confined to nanopores (2.5, 5.0, and 7.5 nm) with lubricated inner surfaces is found to be faster than in the bulk liquid.
Abstract: The molecular dynamics in the glass transition of the “quasi” ‐ van der Waals glass salol confined to nanopores (2.5, 5.0, and 7.5 nm) with lubricated inner surfaces is found to be faster ( by up to 2 orders of magnitude) than in the bulk liquid. This effect of confinement is more pronounced for smaller pores. It reflects the cooperativity of molecular motions in the glass transition and enables its length scale to be determined quantitatively. [S0031-9007(97)04009-X]
330 citations
TL;DR: An excellent sensitivity can be achieved for the combination of mammography and MRI and if appropriately applied and used for selected indications, contrast-enhanced MRI may allow a significant diagnostic gain.
313 citations
TL;DR: The isolation of human (EZH2) and mouse (Ezh1) homologues of the Drosophila Polycomb‐group (Pc‐G) gene Enhancer of zeste [E(z)], a crucial regulator of homeotic gene expression implicated in the assembly of repressive protein complexes in chromatin, is described, indicating that silencing mechanism(s) may be broadly conserved in eukaryotes.
Abstract: Gene silencing is required to stably maintain distinct patterns of gene expression during eukaryotic development and has been correlated with the induction of chromatin domains that restrict gene activity. We describe the isolation of human (EZH2) and mouse (Ezh1) homologues of the Drosophila Polycomb-group (Pc-G) gene Enhancer of zeste [E(z)], a crucial regulator of homeotic gene expression implicated in the assembly of repressive protein complexes in chromatin. Mammalian homologues of E(z) are encoded by two distinct loci in mouse and man, and the two murine Ezh genes display complementary expression profiles during mouse development. The E(z) gene family reveals a striking functional conservation in mediating gene repression in eukaryotic chromatin: extra gene copies of human EZH2 or Drosophila E(z) in transgenic flies enhance position effect variegation of the heterochromatin-associated white gene, and expression of either human EZH2 or murine Ezh1 restores gene repression in Saccharomyces cerevisiae mutants that are impaired in telomeric silencing. Together, these data provide a functional link between Pc-G-dependent gene repression and inactive chromatin domains, and indicate that silencing mechanism(s) may be broadly conserved in eukaryotes.
307 citations
TL;DR: The data imply that repetitive hypoxemia in SAS is probably the cause of the high prevalence of systemic hypertension in this population and that peripheral chemoreceptors and the sympathetic nervous system play important roles in this pathophysiologic process.
Abstract: Background The sleep apnea syndrome (SAS) is a common health problem with a 30% prevalence among patients with so-called essential hypertension. Objective Prompted by this epidemiologic link we tried to find out whether there is a cause-effect relationship between SAS and systemic hypertension. Design We developed an animal model to simulate defined aspects of the SAS. Rats were exposed to chronic repetitive hypoxia for 7 h per day and their blood pressure was measured by invasive methods. Results We found that 30 days of intermittent hypoxia sufficed for the development of a significant elevation of blood pressure. The co-exposure to hypoxia and hypercapnia had no additional effect. Surgical denervation of peripheral chemoreceptors prevented the increase in arterial blood pressure. Adrenal demedullation and chemical denervation of the peripheral sympathetic nervous system by 6-hydroxy dopamine also prevented the increase. Conclusions Our data imply that repetitive hypoxemia in SAS is probably the cause of the high prevalence of systemic hypertension in this population and that peripheral chemoreceptors and the sympathetic nervous system play important roles in this pathophysiologic process.
295 citations
TL;DR: In this paper, the influence of the cut-off distance to the interfacial properties is investigated and long-range corrections to both the dynamics and the surface tension are applied to obtain reliable data for the coexisting densities.
Abstract: In this work we present new molecular dynamics simulation results for the liquid–vapor interface of the pure Lennard-Jones fluid. Our aims were further investigations on the simulation setup and the simulation parameters to obtain reliable data for the coexisting densities as well as for the surface tension. The influence of the cut-off distance to the interfacial properties is investigated and long-range corrections to both the dynamics and the surface tension are applied. It is found that the saturated liquid densities from the surface simulations agree with those from the NpT+test particle method within 1% for sufficiently large simulation boxes; the saturated vapor densities agree within 4%. In order to obtain reliable values for the surface tension, cut-off radii of at least 5 molecular diameters supplemented by a tail correction are required.
292 citations
TL;DR: OA infusion appears to be a safe, effective treatment of chronic (persistent) manifest HE in cirrhotic patients and differential but uniformly significant efficacies in patients with manifest HE with respect to ammonia‐lowering, improvement in NCT times, and mental state gradation are presented.
290 citations
TL;DR: The protein component accelerated the deprotonation of the C2 atom by several orders of magnitude, beyond the rate of the overall enzyme reaction, and the earlier proposed concerted mechanism or stabilization of a C2 carbanion can be excluded.
Abstract: The controversial question of how thiamine diphosphate, the biologically active form of vitamin B1, is activated in different enzymes has been addressed. Activation of the coenzyme was studied by measuring thermodynamics and kinetics of deprotonation at the carbon in the 2-position (C2) of thiamine diphosphate in the enzymes pyruvate decarboxylase and transketolase by use of nuclear magnetic resonance spectroscopy, proton/deuterium exchange, coenzyme analogs, and site-specific mutant enzymes. Interaction of a glutamate with the nitrogen in the 1'-position in the pyrimidine ring activated the 4'-amino group to act as an efficient proton acceptor for the C2 proton. The protein component accelerated the deprotonation of the C2 atom by several orders of magnitude, beyond the rate of the overall enzyme reaction. Therefore, the earlier proposed concerted mechanism or stabilization of a C2 carbanion can be excluded.
272 citations
TL;DR: A plant expression system where the scFv-proteins are targeted in the ER provides not only the highest accumulation level of active single chain Fv antibodies ever reported but also a short- or long-term storage of the foreign protein in the harvested plant material.
TL;DR: It is proposed that the success of the present stabilization strategy is the result of the localization and mutation of an area of the molecule involved in the partial unfolding processes that determine thermal stability.
TL;DR: Eight distinct PPIases with proven enzyme activity in E. coli are known, and it is found that the PPIase activity of SlyD is reversibly regulated by binding of three Ni2+ ions to the histidine-rich, C-terminal region.
TL;DR: Modifications of the vehicle components clarified the extent, to which it is possible to control the penetration of a hydrophilic drug incorporated in a microemulsion (ME) system, and revealed an accumulation of penetrated drug in the dermis, indicating a potential following high absorption rate.
TL;DR: The results suggest a primary inhibition of the mitochondrial respiratory chain by TNFα and IL1α and a subsequent down regulation of PDH activity.
Abstract: Cytokines such as tumor necrosis factor alpha (TNF alpha) and Interleukin-1alpha (IL1alpha) are known to influence energy metabolism and mitochondrial function in tumor and vascular smooth muscle cells. The aim of the present study was to investigate whether in cardiomyocytes mitochondrial function and PDH activity may also be impaired by TNF alpha and IL1alpha. Pyruvate dehydrogenase (PDH) activity and mitochondrial oxygen consumption of cultured cardiomyocytes were determined after subchronic exposure (24 h) to TNF alpha (1, 10, 100, 1000 I.U./ml) and IL1alpha (0.1, 1, 10, 100 I.U./ml). TNF alpha- and IL1alpha- exposure of the cardiomyocytes resulted in a concentration dependent decrease of PDH activity up to 38%. In parallel, selective oxygen consumption of the respiratory chain complexes I (NADH:ubiquinone oxidoreductase) and II (succinate:ubiquinone oxidoreductase) decreased by up to 45%. Addition of the PDH activator dichloracetate (0.01 M) resulted in complete restoration of PDH activity but not of mitochondrial function. The results suggest a primary inhibition of the mitochondrial respiratory chain by TNF alpha and IL1alpha and a subsequent down regulation of PDH activity.
TL;DR: In this paper, a simple technique for the determination of the spatial and temporal transmit-receive field distributions of spherically focused high-frequency transducers is described, where tungsten wires (line-like targets) with diameters less than the acoustic wavelength are used as pulse-echo targets.
Abstract: A simple technique for the determination of the spatial and temporal transmit-receive field distributions of spherically focused high-frequency transducers is described. Instead of a point-like target, tungsten wires (line-like targets) with diameters less than the acoustic wavelength are used as pulse-echo targets. Spatial and temporal field quantities were determined for spherically focused transducers in the frequency range from 3 to 17 MHz, and a comparison with hydrophone measurements showed that both techniques yielded comparable results for the low-frequency transducer. However, for the higher frequency transducers, hydrophone measurements did not yield satisfactory results compared to the wire-target technique due to the hydrophone's aperture size, while the results from the wire-target technique were in general agreement with theory.
TL;DR: Melatonin and serotonin influence on glucose‐stimulated insulin release from perifused rat pancreatic islets in vitro and in vitro shows positive associations with fasting glucose levels and insulin secretion.
Abstract: Peschke E, Peschke D, Hammer T, Csernus V. Influence of melatonin and serotonin on glucose-stimulated insulin release from perifused rat pancreatic islets in vitro. J. Pineal Res. 1997; 23:156–163. © Munksgaard, Copenhagen
Abstract
Insulin plays a key role in the control of glucose homeostasis in mammals. Insulin secretion is regulated by a coordinated interplay of several factors. The role of the indoleamines in the control of insulin secretion has not been fully elucidated yet. The present study was addressed to investigate the function of melatonin and serotonin in the direct control of insulin secretion from the pancreatic islets. Explanted rat Langerhans' islets were treated with melatonin or serotonin while also being exposed to specific (glucose) or non-specific (KC1) stimulus either in a pulsatile or long-term manner in a perifusion system. Insulin content from the effluent tissue culture media was analyzed with RIA. Pulsatile administration of melatonin and serotonin alone did not alter the basal insulin secretion from the explanted islets even at pharmacological (5 μM) level. However, insulin response to specific (glucose) or non-specific (KC1) stimulus was significantly reduced while the islets were treated with melatonin (3 to 12 hr, 10 nM to 5 μM). This effect was reversible and repeatable. Both the start and end of the effect was rapid, evolving and disappearing within 10 min. On the other hand, under similar experimental protocol, serotonin (at 5 μM concentration) significantly enhanced both glucose and KC1 stimulated insulin release. Since the effect of the nonspecific stimulation (with KC1) was also altered, melatonin and serotonin seem to alter not only the release but also the synthesis of the insulin. Our data show that melatonin and serotonin have a direct effect on the insulin secretion from the pancreatic islets.
TL;DR: This work reports that stimulation of human vascular SMC and endothelial cells through CD40 ligand induced elaboration of the IL-1β precursor as well as activation of cell-associated ICE, and indicates a new pathway of ICE-activation, which could participate in inflammatory aspects of atherogenesis and other disease states.
TL;DR: Numerical tests and comparisons with the multistep code VODPK illustrate the efficiency of ROWMAP for large stiff systems and the application to nonautonomous systems is discussed in more detail.
TL;DR: Data suggest that TGF‐β1 might have key functions in the molecular action of DP IV/CD26 in regulation of DNA synthesis and cytokine production.
Abstract: Various studies have shown that the membrane ectoenzyme dipeptidyl peptidase IV (DP IV; CD26), expressed on T, natural killer (NK) and B cells in the immune system, is involved in the regulation of DNA synthesis and cytokine production. We show that the specific DP IV inhibitors Lys[Z(NO2)]-thiazolidide, Lys[Z(NO2)]-piperidide, and Lys[Z(NO2)]-pyrrolidide inhibit DNA synthesis as well as production of interleukin-2 (IL-2), IL-10, IL-12, and interferon-gamma (IFN-gamma) of pokeweed mitogen (PWM)-stimulated purified T cells. Most importantly, these inhibitors induce a three- to fourfold increased secretion of latent transforming growth factor-beta 1 (TGF-beta 1) by PWM-stimulated peripheral blood mononuclear cells (PBMC) and T cells, as measured with a specific TGF-beta 1 enzyme-linked immunosorbent assay and in the Mv1Lu bioassay. As we could demonstrate previously, TGF-beta 1 exhibits the same inhibitory effects as DP IV inhibitors on DNA synthesis and cytokine production (Cytokine 1994, 6, 382-8; J Interferon Cytokine Res 1995, 15, 685-90). A neutralizing chicken anti-TGF-beta 1 antibody was capable of abolishing the DP IV inhibitor-induced suppression of DNA synthesis of PWM-stimulated PBMC and T cells. These data suggest that TGF-beta 1 might have key functions in the molecular action of DP IV/CD26 in regulation of DNA synthesis and cytokine production.
TL;DR: The main stages in the history of electrodialysis, from the discovery of the method in 1890 to the development of the fundamental principles of matter-separation and chemical conversions, are outlined in this paper.
TL;DR: Nattermann et al. as discussed by the authors considered a Langevin-type Eq. which is expected to be valid close to the depinning transition of an interface in a statistically isotropic medium.
Abstract: The dynamics of a driven interface in a medium with random pinning forces is analyzed. The interface undergoes a depinning transition where the order parameter is the interface velocity v, which increases as v ∼(FFc)θ for driving forces F close to its threshold value Fc. We consider a Langevin-type Eq. which is expected to be valid close to the depinning transition of an interface in a statistically isotropic medium. By a functional renormalization group scheme the critical exponents characterizing the depinning transition are obtained to the first order in ϵ = 4 — D > 0, where D is the interface dimension. The main results were published earlier [T. Nattermann et al., J. Phys. II France 2 (1992) 1483]. Here, we present details of the perturbative calculation and of the derivation of the functional flow Eq. for the random-force correlator. The fixed point function of the correlator has a cusp singularity which is related to a finite value of the threshold Fc, similar to the mean field theory. We also present extensive numerical simulations and compare them with our analytical results for the critical exponents. For ϵ = 1 the numerical and analytical results deviate from each other by only a few percent. The deviations in lower dimensions ϵ = 2, 3 are larger and suggest that the roughness exponent is somewhat larger than the value ξ = e/3 of an interface in thermal equilibrium.
TL;DR: Results show that aspirin protects endothelial cells from oxidative stress possibly via binding or chelation of free cytosolic iron, and a combination of aspirin and vitamin E might be useful for the prevention of endothelial injury in cardiovascular disease, e.g. during atherogenesis.
TL;DR: In this article, the relationship between dissociative experiences, trait-anxiety and paranormal beliefs among students was investigated and significant gender differences were found; females scored higher than males on the Dissociative Experience Scale (DES) by Bernstein and Putnam (The Journal of Nervous and Mental Disease, 174, 727-735, 1986) and some subscales of the revised Paranormal Belief Scale by Tobacyk (A Revised Paranormal belief Scale, unpublished manusript, 1991), such as psi belief, witchcraft, superstition and precognition.
TL;DR: Human cardiacmuscarinic receptor activity is diminished with increasing age; such decreased cardiac muscarinic receptors activity could contribute to the decrease in baroreflex activity with aging.
TL;DR: In this paper, hybrid plasmids of pBluescript vectors were constructed which harbored the Alcaligenes eutrophus PHA synthase gene (phaC) and the Clostridium kluyveri orfZ putatively encoding a 4-hydroxybutyric acid-coenzyme A transferase.
Abstract: The aim of this study was the production of the homopolyester poly(4-hydroxybutyric acid) (poly(4HB)) with recombinant strains of Escherichia coli Wild-type strains and other widely used non-recombinant strains of E coli are not able to produce polyhydroxyalkanoic acids (PHA) as storage compounds and cannot utilize 4-hydroxybutyric acid as sole carbon source Accordingly, hybrid plasmids of pBluescript vectors were constructed which harbored the Alcaligenes eutrophus PHA synthase gene (phaC) and the Clostridium kluyveri orfZ putatively encoding a 4-hydroxybutyric acid-coenzyme A transferase A 35-kb genomic SmaI/ApaI fragment from A eutrophus, which comprises phaC, and a 18-kb genomic ApaI/EcoRI fragment from C kluyveri, which contained orfZ, were inserted into the SmaI and EcoRI sites of the vectors pKS− and pSK−, respectively The two resulting plasmids pSKSE53 and pKSSE53 comprising phaC and orfZ colinear or antilinear to lacZ, respectively, were transformed into E coli XL1-Blue Recombinant strains synthesized the homopolyester poly(4HB), when the cells were cultivated in Luria-Bertani broth and if glucose and 4-hydroxybutyric acid were provided as carbon sources If glucose was omitted, a copolyester of 3-hydroxybutyric acid and 4-hydroxybutyric acid was accumulated The homopolyester poly(4HB) was also accumulated during cultivation of these strains in M9 mineral salts medium containing glucose plus 4-hydroxybutyric acid as carbon sources Poly(4HB) could amount up to approximately 80% (w/w) of the cell dry matter if E coli XL1-Blue harboring pKSSE53 was cultivated in M9 mineral salts medium and if the cultures were not sufficiently supplied with oxygen 4HB was also incorporated into PHA if γ-butyrolactone was used as carbon source If levulinic acid, 4-hydroxyvaleric acid or γ-valerolactone were used as carbon sources, only very low amounts of PHA were accumulated which did not contain 4-hydroxyalkanoic acids as constituents
TL;DR: In this paper, the cellular and intracellular distributions of heavy metals were investigated by conventional electron microscopy, EDX, ESI and EELS, and the possible mechanisms of heavy metal tolerance in Minuartia and the role of Si in these processes were discussed.
TL;DR: In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as astatistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma.
Abstract: Despite the use of multimodal therapy, higher-grade glioma is stilluniformly fatal in the adult population. There is a considerable differencebetween the length of survival in each given patient, even within the sametumor type and malignancy grade group, suggesting that there are factorsthat might differentially influence outcome. To identify such factors, 107patients with anaplastic or malignant glioma were retrospectivelyinvestigated. Clinical parameters and paraclinical data on the p53, mdm2,and EGFR genes at the DNA or protein level were evaluated by univariateanalysis and Cox proportional hazards regression modeling. Kaplan-Meiersurvival estimation demonstrated that immunohistochemical positivity formdm2 protein in patients with anaplastic astrocytoma or with glioblastomamultiforme was associated with a shorter survival time (p = 0.02).P53 gene mutations and immunopositivity for the epidermal growth factorreceptor (EGFR) protein were not significantly related to poor prognosis.The Cox proportional hazards model revealed immunohistochemical positivityfor p53, mdm2, or for both of them, the presence of postoperativeirradiation, and the extent of surgical resection of tumor to be variablessignificantly associated with prolonged survival. EGFR overexpression, ageover 60 years, and Karnofsky performance score below 40 points did notsignificantly shorten survival time. In conclusion, the present studyidentified immunohistochemically detected mdm2-protein overexpression as astatistically significant negative prognostic parameter in patients bearinganaplastic or malignant glioma. Association analysis of variables revealed apossible correlation between mdm2 and p53, which is also consistent with thebiological interaction mode of both proteins in vivo.
TL;DR: Fluid inclusions were studied in samples from the Ashanti, Konongo-Southern Cross, Prestea, Abosso/Damang and Ayanfuri gold deposits in Ghana as discussed by the authors.
Abstract: Fluid inclusions were studied in samples from the Ashanti, Konongo-Southern Cross, Prestea, Abosso/Damang and Ayanfuri gold deposits in the Ashanti Belt, Ghana. Primary fluid inclusions in quartz from mineralised veins of the Ashanti, Prestea, Konongo-Southern Cross, and Abosso/Damang deposits contain almost exclusively volatile species. The primary setting of the gaseous (i.e. the fluid components CO2, CH4 and N2) fluid inclusions in clusters and intragranular trails suggests that they represent the mineralising fluids. Microthermometric and Raman spectroscopic analyses of the inclusions revealed a CO2 dominated fluid with variable contents of N2 and traces of CH4. Water content of most inclusions is below the detection limits of the respective methods used. Aqueous inclusions are rare in all samples with the exception of those from the granite-hosted Ayanfuri mineralisation. Here inclusions associated with the gold mineralisation contain a low salinity ( CO2 and low salinity ( ± 6 eq.wt.%NaCl). However, fluid inclusions in quartz from the gold mineralisations in the Ashanti belt point to distinctly different fluid compositions. Specifically, the predominance of CO2 and CO2 >> H2O have to be emphasized. Fluid systems with this unique bulk composition were apparently active over more than 200␣km along strike of the Ashanti belt. Fluids rich in CO2 may present a hitherto unrecognised new category of ore-forming fluids.