Response variability in balanced cortical networks

We study the spike statistics of neurons in a network with dynamically balanced excitation and inhibition. Our model, intended to represent a generic cortical column, comprises randomly connected excitatory and inhibitory leaky integrate-and-fire neurons, driven by excitatory input from an external population. The high connectivity permits a mean-field description in which synaptic currents can be treated as Gaussian noise, the mean and autocorrelation function of which are calculated self-consistently from the firing statistics of single model neurons. Within this description, we find that the irregularity of spike trains is controlled mainly by the strength of the synapses relative to the difference between the firing threshold and the post-firing reset level of the membrane potential. For moderately strong synapses we find spike statistics very similar to those observed in primary visual cortex.Comment: 22 pages, 7 figures, submitted to Neural Computatio

Risk assessment of contrast-induced acute kidney injury in patients with acute myocardial infarction after coronary angiography and percutaneous coronary intervention

Aim. To assess the risk of contrast-induced acute renal injury (CI-AKI) in patients with acute myocardial infarction in a highly specialized hospital after coronary angiography.Material and methods. The study sample included 502 patients who were treated in the cardiology department of a specialized hospital. CI-AKI was established by an increase in creatinine >26 μmol/L within 48 hours after percutaneous coronary intervention (PCI) with radiopaque contrast agents or an increase in creatinine >50% within a week after PCI. A multistage statistical analysis was used to search for possible predictors of CI-AKI.Results. In total, CI-AKI was diagnosed in 57 (11,3%) patients. Based on the analysis performed, 3 significant predictors of CI-AKI were identified: patient’s age, contrast medium volume (ml/kg) and anemia (presence/absence). An equation for assessing the risk of CI-AKI in patients after PCI has been created.Conclusion. A simple scale for assessing the CI-AKI risk makes it possible to identify a category of patients who requires preventive measures to reduce iatrogenic complications and mortality

КОНТРАСТ-ИНДУЦИРОВАННАЯ НЕФРОПАТИЯ У БОЛЬНЫХ С ОСТРЫМ КОРОНАРНЫМ СИНДРОМОМ

The article discusses the issue of renal complications in coronary arteries interventions. A review of the latest researches about contrast-induced nephropathy occurrence in patients with acute coronary syndrome is presented. We gave a definition of a contrast-induced nephropathy, its pathogenesis and development risk factors, characteristics of radiopaque substances, preventive measures of contrastinduced nephropathy in patients with acute coronary syndrome. В статье обсуждается проблема почечных осложнений при интервенционных вмешательствах на коронарных артериях. Представлен обзор последних исследований возникновения контраст-индуцированной нефропатии у больных с острым коронарным синдромом. Приведены определения контраст-индуцированной нефропатии, ее патогенез и факторы риска развития, характеристика рентгенконтрастных веществ, меры профилактики контраст-индуцированной нефропатии у больных с острым коронарным синдромом