3,912 research outputs found

    Mechanismus der enzymatischen Freisetzung von Acetaldehyd aus “aktivem Acetaldehyd” (α-hydroxyaethyl-2-thiaminpyrophosphat)

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    1. 1.Die Freisetzung von Acetaldehyd aus “Aktivem Acetaldehyd” mit gereinigter Apopyruvatdecarboxylase aus Bierhefe wird durch. Thiaminpyrophosphat gehemmt. Diese Konkurrenzhemmung erklärt (zumindest teilweise) die langsame Freisetzung von Acetaldehyd beim enzymatischen Umsatz von Präparaten, die viel Thiamin-pyrophosphat enthalten. 2. 2. Die Freisetzung von Acetaldehyd aus “Aktivem Acetaldehyd” mit Apo-carboxylase erfolgt nicht in einer früher von uns diskutierten Austauschreaktion mit Pyruvat, sondern in einer direkten Reaktion: Aktiver Acetaldehyd å Acetaldehyd + TPP.1. 1. The enzymic formation of acetaldehyde from α-hydroxyethyl thiamine pyrophosphate with purified apopyrubate decarboxylase from yeast is inhibited by thiamine pyrophosphate. This inhibition explains (at least partly) the slow enzymic production of acetaldehyde from α-hydroxyethyl thiamine pyrophosphate preparations containing a considerable amount of thiamine pyrophosphate. 2. 2. The enzymic formation of acetaldehyde from α-hydroxyethyl thiamine pyrophosphate with apocarboxylase does not take place in form of an exchange reaction with pyruvate, as discussed earlier, but in form of the direct reaction: α-hydroxyethyl thiamine pyrophosphate → acetaldehyde + thiamine pyrophosphate

    Wirkung carcinostatischer äthylenimin-verbindungen auf den DPN-gehalt therapieresistener tumoren

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    Preliminary experiments with the ascites form of the relatively therapeutic-resistant DS-tumour demonstrated that the decrease in DPN content and the inhibition of glycolysis in the neoplastic cells under the influence of ethylenimine compounds were delayed, in comparison with the rapid changes observed in Ehrlich-ascites carcinomas. Extending these observations, the therapeutic effect of carcinostatic ethylenimine compounds was studied in rats bearing solid forms of either the Jensen sarcoma or the therapeutic-resistant DS-tumour. During the course of the experiments the DPN content of the tumours was followed. In the Jensen sarcoma the DPN content decreased sharply as early as the first day following administration of the carcinostatic, while the DS-tumour, in contrast, showed no clear change during the first six days. A cure was obtained in nine out of thirteen cases of the Jensen-sarcoma rats, while no cure was observed in six DS-tumour-bearing rats. These experiments further support our hypothesis, that carcinostatic ethylenimine compounds are therapeutically effective though they depress the DPN content in the tumour

    Politik i det refleksive moderne: fra livspolitik til subpolitik

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    Temaets tredje artikel – Boris Holzer og Mads P. Sørensens artikel ”Politik i det refleksive moderne: fra livspolitik til subpolitik” tager Becks begreb om subpolitik under behandling

    Rabies prophylaxis after an animal attack that caused a ruptured eye and traumatic cataract: a case report

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    Introduction: We report on a patient with an animal bite eye injury, his surgical treatment and proper rabies immunoglobulin administration. Case presentation: A 33-year-old Turkey hunter was attacked by a bobcat and his injuries included a ruptured globe with corneal laceration, two iris sphincter tears, and a ruptured anterior capsule with a traumatic cataract. Rabies vaccination was started, primary closure of the corneal laceration, an anterior chamber washout and one week later cataract surgery were performed. Three months postoperatively he achieved an uncorrected visual acuity of 20/50 and a best corrected visual acuity of 20/20. Conclusion: Bobcat attacks on humans are very rare and extremely suspicious for rabies infection of the animal. Ophthalmologists need to be aware of the importance of immediate and appropriate post exposure rabies vaccination. Proper rabies immunoglobulin administration in the setting of globe injuries is challenging and we report on the Center for Disease Control and Prevention recommendations for globe injuries

    Particles held by springs in a linear shear flow exhibit oscillatory motion

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    The dynamics of small spheres, which are held by linear springs in a low Reynolds number shear flow at neighboring locations is investigated. The flow elongates the beads and the interplay of the shear gradient with the nonlinear behavior of the hydrodynamic interaction among the spheres causes in a large range of parameters a bifurcation to a surprising oscillatory bead motion. The parameter ranges, wherein this bifurcation is either super- or subcritical, are determined.Comment: 4 pages, 5 figure

    Towards Collaborative Conceptual Exploration

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    In domains with high knowledge distribution a natural objective is to create principle foundations for collaborative interactive learning environments. We present a first mathematical characterization of a collaborative learning group, a consortium, based on closure systems of attribute sets and the well-known attribute exploration algorithm from formal concept analysis. To this end, we introduce (weak) local experts for subdomains of a given knowledge domain. These entities are able to refute and potentially accept a given (implicational) query for some closure system that is a restriction of the whole domain. On this we build up a consortial expert and show first insights about the ability of such an expert to answer queries. Furthermore, we depict techniques on how to cope with falsely accepted implications and on combining counterexamples. Using notions from combinatorial design theory we further expand those insights as far as providing first results on the decidability problem if a given consortium is able to explore some target domain. Applications in conceptual knowledge acquisition as well as in collaborative interactive ontology learning are at hand.Comment: 15 pages, 2 figure

    EHR-Based Care Coordination Performance Measures in Ambulatory Care

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    Describes electronic health record-based measures for assessing coordination in referrals, including information communicated with referral, communication to patient, and specialist report to primary care physician. Offers preliminary evaluation findings

    Afferent signalling from the acid-challenged rat stomach is inhibited and gastric acid elimination is enhanced by lafutidine

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    <p>Abstract</p> <p>Background</p> <p>Lafutidine is a histamine H<sub>2 </sub>receptor antagonist, the gastroprotective effect of which is related to its antisecretory activity and its ability to activate a sensory neuron-dependent mechanism of defence. The present study investigated whether intragastric administration of lafutidine (10 and 30 mg/kg) modifies vagal afferent signalling, mucosal injury, intragastric acidity and gastric emptying after gastric acid challenge.</p> <p>Methods</p> <p>Adult rats were treated with vehicle, lafutidine (10 – 30 mg/kg) or cimetidine (10 mg/kg), and 30 min later their stomachs were exposed to exogenous HCl (0.25 M). During the period of 2 h post-HCl, intragastric pH, gastric volume, gastric acidity and extent of macroscopic gastric mucosal injury were determined and the activation of neurons in the brainstem was visualized by c-Fos immunocytochemistry.</p> <p>Results</p> <p>Gastric acid challenge enhanced the expression of c-Fos in the nucleus tractus solitarii but caused only minimal damage to the gastric mucosa. Lafutidine reduced the HCl-evoked expression of c-Fos in the NTS and elevated the intragastric pH following intragastric administration of excess HCl. Further analysis showed that the gastroprotective effect of lafutidine against excess acid was delayed and went in parallel with facilitation of gastric emptying, measured indirectly via gastric volume changes, and a reduction of gastric acidity. The H<sub>2 </sub>receptor antagonist cimetidine had similar but weaker effects.</p> <p>Conclusion</p> <p>These observations indicate that lafutidine inhibits the vagal afferent signalling of a gastric acid insult, which may reflect an inhibitory action on acid-induced gastric pain. The ability of lafutidine to decrease intragastric acidity following exposure to excess HCl cannot be explained by its antisecretory activity but appears to reflect dilution and/or emptying of the acid load into the duodenum. This profile of actions emphasizes the notion that H<sub>2 </sub>receptor antagonists can protect the gastric mucosa from acid injury independently of their ability to suppress gastric acid secretion.</p
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