The significance of a fast exchanging superficial calcium fraction for the regulation of contractile force in heart muscle

The force of contraction of isolated guinea-pig atria decreased with time during 5 h of incubation in Tyrode solution containing 0.9 mm-CaCl₂. The relative effect of ouabain strongly depended on the duration of incubation (“age”) of the tissue. Freshly dissected atria showed a 12% increase in contractile force, whereas aged atria (5 h of incubation) produced a 240% increase in tension in the presence of ouabain (1.5 × 10^?7m).In freshly dissected atrial preparations, after an equilibration period of 30 mins, ouabain had no influence on Ca metabolism (total tissue Ca, rate of exchange, and size of exchangeable fraction). After aging of the tissue the rate of Ca exchange was significantly decreased, and ouabain considerably accelerated the Ca exchange rate.The presence of pentobarbital also slowed the Ca exchange rate. Ouabain was able completely to restore the rate of Ca exchange to control valves.Analysis of the Ca exchange curves yielded a fast and a slowly exchanging Ca compartment. The size of the fast exchanging fraction was significantly reduced by aging and by the treatment with pentobarbital. Under these conditions ouabain enhanced the size of this particular Ca compartment. It is suggested that the fast exchanging Ca compartment is superficially located and is responsible for rapid changes in contractile force. This Ca fraction may provide a Ca concentration of about 1.5 × 10^?5m in the intracellular aqueous space, which is generally believed to be sufficient for the activation of contraction.     

Early effect of thrombolysis on structural brain network organisation after anterior‐circulation stroke in the randomized WAKE‐UP trial

The symptoms of acute ischemic stroke can be attributed to disruption of the brain network architecture. Systemic thrombolysis is an effective treatment that preserves structural connectivity in the first days after the event. Its effect on the evolution of global network organisation is, however, not well understood. We present a secondary analysis of 269 patients from the randomized WAKE‐UP trial, comparing 127 imaging‐selected patients treated with alteplase with 142 controls who received placebo. We used indirect network mapping to quantify the impact of ischemic lesions on structural brain network organisation in terms of both global parameters of segregation and integration, and local disruption of individual connections. Network damage was estimated before randomization and again 22 to 36 h after administration of either alteplase or placebo. Evolution of structural network organisation was characterised by a loss in integration and gain in segregation, and this trajectory was attenuated by the administration of alteplase. Preserved brain network organization was associated with excellent functional outcome. Furthermore, the protective effect of alteplase was spatio‐topologically nonuniform, concentrating on a subnetwork of high centrality supported in the salvageable white matter surrounding the ischemic cores. This interplay between the location of the lesion, the pathophysiology of the ischemic penumbra, and the spatial embedding of the brain network explains the observed potential of thrombolysis to attenuate topological network damage early after stroke. Our findings might, in the future, lead to new brain network‐informed imaging biomarkers and improved prognostication in ischemic stroke.     

Neuritis retrobulbaris (Leber) und endokrines System

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Bindehautplastik bei schweren Verätzungen in der chemischen Industrie

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Neurithrit,Ein Neues Antineuralgicum

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Behandlung von Blutungen in der Schwangerschaft

Archives of Gynecology and Obstetrics -     

Die Frühplastik bei Verätzungen des Auges

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Nochmals die rhinogene Neuritis retrobulbaris

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