556 research outputs found
Heavy Ion Collisions and the Density Dependence of the Local Mean Field
We study the effect of the density dependence of the scalar and the vector
part of the nucleonic self-energy in Relativistic Quantum Molecular Dynamics
(RQMD) on observables like the transversal flow and the rapidity distribution.
The stability of nuclei in RQMD is greatly improved if the density dependence
is included in the self-energies compared to a calculation assuming always
saturation density of nuclear matter. Different approaches are studied: The
main results are calculated with self-energies extracted from a
Dirac-Br\"uckner-Hartree-Fock G-matrix of a one boson exchange model, i.e. the
Bonn potential. These results are compared with those obtained by a
generalization of static Skyrme force, with calculations in the simple linear
Walecka model and results of the Br\"uckner-Hartree-Fock G-matrix of the Reid
soft core potential. The transversal flow is very sensitive to these different
approaches. A comparison with the data is given.Comment: LaTex-file, 13 pages, 5 figures (available upon request), submitted
to Nuclear Physics
Mineralocorticoid receptors in nonâalcoholic fatty liver disease
Liver diseases are the fourth common death in Europe responsible for about 2 million death per year worldwide. Among the known detrimental causes for liver dysfunction are virus infections, intoxications and obesity. The mineralocorticoid receptor (MR) is a ligandâdependent transcription factor activated by aldosterone or glucocorticoids but also by pathological milieu factors. Canonical actions of the MR take place in epithelial cells of kidney, colon and sweat glands and contribute to sodium reabsorption, potassium secretion and extracellular volume homeostasis. The nonâcanonical functions can be initiated by inflammation or an altered microâmilieu leading to fibrosis, hypertrophy and remodelling in various tissues. This narrative review summarizes the evidence regarding the role of MR in portal hypertension, nonâalcoholic fatty liver disease, liver fibrosis and cirrhosis, demonstrating that inhibition of the MR in vivo seems to be beneficial for liver function and not just for volume regulation. Unfortunately, the underlying molecular mechanisms are still not completely understood
What predicts improvement of dizziness after multimodal and interdisciplinary day care treatment?
Background: Vertigo and dizziness are common in community-dwelling people and can be treated in specialized multidisciplinary settings. To develop tailored interventions, however, we have to explore risk factors for favorable and unfavorable outcomes. Methods: We prospectively investigated patients with chronic vertigo and dizziness subjected to our 5-day multimodal and interdisciplinary day care treatment in the Center for Vertigo and Dizziness of Jena University Hospital, Germany. The Vertigo Severity Scale (VSS), the Body Sensations Questionnaire (BSQ), the Hospital Anxiety and Depression Scale (HADS), the Agoraphobic Cognitions Questionnaire (ACQ), the Mobility Inventory (MI), and the burden and intensity of dizziness (using a visual analogue scale) were assessed at baseline ( n = 754) and after 6 months ( n = 444). In addition, 14 Likert-scaled questions were used to quantify the change in personal attitude and behavior towards the complaints after 6 months. Results: Dizziness-related burden and intensity improved with a large effect size. The largest improvement was seen in the attitudes towards dizziness, the understanding of somatic causes, and the perceived ability to influence dizziness. However, the ability to work and to carry out professional activity was improved to a lesser extent. The overall improvement of dizziness was associated with the absence of a depressive mood, a short duration of vertigo, a lower VSS, a lower perceived intensity of vertigo, and distinct vertigo diagnoses, namely Meniereâs disease, vestibular migraine, vestibular neuritis, vestibular paroxysmia, and vestibular schwannoma. Worsening of dizziness/vertigo was associated with depressive symptoms, permanent vertigo, distinct vertigo diagnoses (central vertigo, multisensory deficit), and a higher perceived burden due to vertigo. Conclusion: The six-month outcome of patients with dizziness presented to a specialized outpatient clinic appears to be favorable. Nevertheless, people with the abovementioned risk factors at baseline have less benefit and probably need adapted and tailored vertigo interventions to improve long-term outcome
Impact of depression, resilience, and locus of control on adjustment of health-related expectations in aging individuals with chronic illness
Objectives Quality of Life (QoL) depends on the discrepancy between desired and current experiences (referred to as the Calman gap), thus in chronic illness, adjustment of expectations and interpretation of the current situation are crucial. Depression is known to influence this gap, and the present study aims to further assess the role of resilience and health locus of control (HLC). Methods A total of 94 patients (age M = 71.8, SD = 7.7 years) with neurological disorders were screened via telephone regarding depression, resilience and HLC. Current and desired state of several life domains were assessed, such as Fitness, General Health, Pain, Daily Activities, Finances, Leisure, and Family. Elastic net regularization and analyses of variance were used to disentangle the impact of depression, resilience, HLC, and sociodemographic factors on the perception of current and desired state, and the gap between both. Results A gap was present for all domains but largest for pain. Interpretation of the current state was linked to desired state, HLC, and age. All gaps were related to depression; certain domains were in addition influenced by resilience, HLC and sociodemographic factors. Of note, for most domains, patients did not select the highest possible desired state. Conclusion Older patients with neurological disorders report a gap between current and desired state for many aspects of life. Adjusting expectations is beneficial in the face of declining health, but a reasonably increased desired state may positively influence the perception of the current situation. Depression negatively influences the interpretation of the Calman gap
Untersuchung ausgewÀhlter Translationsinitiationsfaktoren nach Spreading Depolarization zur Analyse der globalen Proteinsynthese
Spreading Depolarizations (SD) sind ein pathophysiologisches PhĂ€nomen, das bei verschiedenen Erkrankungen des Gehirns wie z.B. der IschĂ€mie auftritt. In frĂŒheren Studien ist bereits eine Beeinflussung der Proteinsynthese durch SD gezeigt worden. Auch nach IschĂ€mie ist eine Regulation der Proteinsynthese durch Regulation der Expression und AktivitĂ€t von Translationsinitiationsfaktoren (TIF) bereits bekannt. Allerdings wurde hier meist ischĂ€misches Gewebe mituntersucht, in dem neben den SD weitere pathologische Mechanismen ablaufen, die die Proteinsynthese beeinflussen. In der vorliegenden Studie wurden erstmalig drei fĂŒr die Proteinsynthese essentielle TIF in einem Zeitraum bis zu 30 Tagen nach SD im ansonsten gesunden Gewebe untersucht. HierfĂŒr wurden SD bei Wistar-Ratten in vivo mittels Applikation von 1 M KCl induziert und das Gehirngewebe zu sieben unterschiedlichen Zeitpunkten nach SD analysiert. Dabei wurde nicht nur die Expression der TIF (eIF2α, eIF4E und p70S6-Kinase), sondern auch deren Lokalisation und Phosphorylierungsgrad untersucht. Es wurde eine signifikante Steigerung der Expression der p70S6-Kinase 4 und 8 Stunden nach SD sowie der Phosphorylierung von eIF2α 8 Stunden nach SD gefunden. Insgesamt weisen die in dieser Studie erhobenen Daten darauf hin, dass zumindest einige der bisher nach SD beobachteten VerĂ€nderungen der Proteinsynthese auf eine Regulation der TIF zurĂŒckzufĂŒhren sind. AuĂerdem wurden Hinweise darauf gefunden, dass SD an der Beeinflussung der Proteinsynthese nach globaler und fokaler IschĂ€mie beteiligt sind. Weiterhin konnten in der vorliegenden Studie Hinweise auf ZusammenhĂ€nge der Regulation der Proteinsynthese nach SD mit anderen pathophysiologischen VorgĂ€ngen wie der Stressreaktion und der Induktion einer IschĂ€mietoleranz nach SD gefunden werden. Damit trĂ€gt die vorliegende Studie zur Erweiterung des VerstĂ€ndnisses der Pathophysiologie von SD bei
Osseointegration of zirconia implants compared with titanium : an in vivo study
Background Titanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental role in osseointegration, various chemical and physical surface modifications have been developed to improve osseous healing. Zirconia-based implants were introduced into dental implantology as an altenative to titanium implants. Zirconia seems to be a suitable implant material because of its tooth-like colour, its mechanical properties and its biocompatibility. As the osseointegration of zirconia implants has not been extensively investigated, the aim of this study was to compare the osseous healing of zirconia implants with titanium implants which have a roughened surface but otherwise similar implant geometries. Methods Forty-eight zirconia and titanium implants were introduced into the tibia of 12 minipigs. After 1, 4 or 12 weeks, animals were sacrificed and specimens containing the implants were examined in terms of histological and ultrastructural techniques. Results Histological results showed direct bone contact on the zirconia and titanium surfaces. Bone implant contact as measured by histomorphometry was slightly better on titanium than on zirconia surfaces. However, a statistically significant difference between the two groups was not observed. Conclusion The results demonstrated that zirconia implants with modified surfaces result in an osseointegration which is comparable with that of titanium implants
Influence of the pion-nucleon interaction on the collective pion flow in heavy ion reactions
We investigate the influence of the real part of the in-medium pion optical
potential on the pion dynamics in intermediate energy heavy ion reactions at 1
GeV/A. For different models, i.e. a phenomenological model and the
--hole model, a pionic potential is extracted from the dispersion
relation and used in Quantum Molecular Dynamics calculations. In addition with
the inelastic scattering processes we thus take care of both, real and
imaginary part of the pion optical potential. A strong influence of the real
pionic potential on the pion in-plane flow is observed. In general such a
potential has the tendency to reduce the anticorrelation of pion and nucleon
flow in non-central collisions.Comment: 12 pages Latex, 4 PS-figure
Protective Effects of Statin Therapy in Cirrhosis Are Limited by a Common SLCO1B1 Transporter Variant
Complications of cirrhosis and portal hypertension (PH) can be reduced by statin therapy. The common loss-of-function variant p.V174A in the solute carrier organic anion transporter gene 1B1 (SLCO1B1) gene encoding the organic anion transporting polypeptide 1B1 results in decreased hepatic uptake of statins. Our specific aim was to assess the impact of this variant in patients with cirrhosis and statin treatment while controlling for the stage of cirrhosis and other potential confounders with propensity score matching (PSM), availing of a large cohort of genotyped study patients. In total, from 1,088 patients with cirrhosis in two German academic medical centers, PSM yielded 154 patients taking statins and 154 matched controls. The effect on PH was assessed by the liver stiffnessâspleen sizeâtoâplatelet score (LSPS), and complications of cirrhosis were retrospectively recorded applying consensus criteria. As hypothesized, patients on statin treatment presented less frequently with signs of PH: Esophageal varices (41% vs. 62%; P < 0.001) were less common, and LSPS (4.8 ± 11.5 vs. 5.6 ± 6.4; P = 0.01) was reduced. Correspondingly, decompensation events were also reduced in patients on statins (odds ratio [OR] = 0.54, 95% confidence interval [CI] 0.32-0.90; P = 0.02). When the variant in SLCO1B1 was present in patients on statins, esophageal varices (OR = 2.68, 95% CI 1.24-5.81; P = 0.01) and bacterial infections (OR = 2.50, 95% CI 1.14-5.47; P = 0.02) were more common as compared with wild type carriers on statins.
Conclusion: In this cohort, signs and complications of PH were reduced in patients with cirrhosis treated with statins. Notably, this effect was diminished by the common loss-of-function variant in SLCO1B1. Further prospective studies in independent cohorts are warranted to confirm these genotype-specific observations
Behavior of osteoblastic cells cultured on titanium and structured zirconia surfaces
Background Osseointegration is crucial for the long-term success of dental implants and depends on the tissue reaction at the tissue-implant interface. Mechanical properties and biocompatibility make zirconia a suitable material for dental implants, although surface processings are still problematic. The aim of the present study was to compare osteoblast behavior on structured zirconia and titanium surfaces under standardized conditions. Methods The surface characteristics were determined by scanning electron microscopy (SEM). In primary bovine osteoblasts attachment kinetics, proliferation rate and synthesis of bone-associated proteins were tested on different surfaces. Results The results demonstrated that the proliferation rate of cells was significantly higher on zirconia surfaces than on titanium surfaces (p < 0.05; Student's t-test). In contrast, attachment and adhesion strength of the primary cells was significant higher on titanium surfaces (p < 0.05; U test). No significant differences were found in the synthesis of bone-specific proteins. Ultrastructural analysis revealed phenotypic features of osteoblast-like cells on both zirconia and titanium surfaces. Conclusion The study demonstrates distinct effects of the surface composition on osteoblasts in culture. Zirconia improves cell proliferation significantly during the first days of culture, but it does not improve attachment and adhesion strength. Both materials do not differ with respect to protein synthesis or ultrastructural appearance of osteoblasts. Zirconium oxide may therefore be a suitable material for dental implants
Imaging Findings of Gastric Diverticula
Introduction. Gastric diverticula (GD) are very rare. Computer tomographic findings in GD have been reported only as case reports previously. The aim of this study was to estimate the prevalence of GD on computed tomography (CT) and to analyze their radiological appearances. Materials and Methods. From 2006 to 2013, a total of 14,428 patients were examined by abdominal/thoracic CT at our institution. GD were diagnosed in 18 (0.12%) patients (13 women and 5 men, median age, 64 years). In 9 patients, additional endoscopy and in 7 patients upper gastrointestinal investigation with contrast medium were performed. Magnetic resonance imaging (MRI) was available for 3 cases. Results. In all patients GD were diagnosed incidentally during CT examination. The diverticula were located at the posterior wall of the gastric fundus below the esophagogastric junction. On CT, GD presented as cystic lesions with a thin wall and an air fluid level, located behind the stomach between spleen, adrenal gland, and crus of the left diaphragm. Conclusion. The prevalence of GD encountered in our CT series is 0.12%. GD demonstrate typical CT appearances, namely, cystic lesions located in the left paravertebral region. The radiologist should be familiar with this finding to avoid possible misinterpretations
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