A mean-field approach to the dynamics of networks of complex neurons, from nonlinear Integrate-and-Fire to Hodgkin-Huxley models.

We present a mean-field formalism able to predict the collective dynamics of large networks of conductance-based interacting spiking neurons. We apply this formalism to several neuronal models, from the simplest Adaptive Exponential Integrate-and-Fire model to the more complex Hodgkin-Huxley and Morris-Lecar models. We show that the resulting mean-field models are capable of predicting the correct spontaneous activity of both excitatory and inhibitory neurons in asynchronous irregular regimes, typical of cortical dynamics. Moreover, it is possible to quantitatively predict the population response to external stimuli in the form of external spike trains. This mean-field formalism therefore provides a paradigm to bridge the scale between population dynamics and the microscopic complexity of the individual cells physiology.NEW & NOTEWORTHY Population models are a powerful mathematical tool to study the dynamics of neuronal networks and to simulate the brain at macroscopic scales. We present a mean-field model capable of quantitatively predicting the temporal dynamics of a network of complex spiking neuronal models, from Integrate-and-Fire to Hodgkin-Huxley, thus linking population models to neurons electrophysiology. This opens a perspective on generating biologically realistic mean-field models from electrophysiological recordings.

Influence of physiotherapy on severity of motor symptoms and quality of life in patients with Parkinson disease.

BACKGROUND AND PURPOSE: Parkinson disease (PD) is one of the most frequent diseases of the central nervous system. Rehabilitation is one of the factors which may help the patients to maintain higher physical activity in everyday life. The aim of this work was to evaluate the influence of movement rehabilitation on severity of motor symptoms in PD patients. MATERIAL AND METHODS: The study included 70 patients suffering from PD according to the Hoehn and Yahr scale. Patients' clinical status was assessed with Unified Parkinson's Disease Rating Scale (UPDRS) parts I-III. Additionally, activity of daily living was evaluated with the Schwab and England scale. The quality of life was evaluated by the Parkinson's Disease Questionnaire (PDQ-39). The examinations were conducted before and after the twelve weeks of the experiment. Patients included in the intervention group (n = 40) took part in 60-minute rehabilitation exercises twice a week, which were aimed at increasing movement ranges, balance improvement, movement agility and walking. The main emphasis was placed on the ability to cope with daily activities. RESULTS: A significant difference in scores of given scales before and after the 12-week period was observed in the intervention group: UPDRS part I score decreased by 17.31%, part II decreased by 22.2%, part III decreased by 18.96%, and PDQ-39 score decreased by 17.12%. Mean score of the Schwab and England scale increased by 9.69%, indicating an improved quality of life. CONCLUSIONS: The applied rehabilitation programme decreased the severity of motor symptoms in patients with PD.

Adenovirus Dodecahedron, a VLP, Can be Purified by Size Exclusion Chromatography Instead of Time-Consuming Sucrose Density Gradient Centrifugation.

Adenoviral dodecahedron (Dd) is a virus-like particle composed of twelve pentameric penton base (Pb) proteins, responsible for adenovirus cell penetration. It is generated spontaneously in the baculovirus system upon expression of the Pb gene of adenovirus serotype 3. This particle shows remarkable cell penetration ability with 2,00,000-3,00,000 Dd internalized into one cell in culture, conceivably delivering several millions of foreign cargo molecules to the target cell. We have used it in the past for delivery of small drugs as well as a vaccination platform, in which Dd serves as a particulate vaccine delivery system. Since development of new biomedicals depends strongly on the cost of their expression and purification, we attempted, albeit unsuccessfully, to obtain Dd expression in bacteria. We therefore retained its expression in the baculovirus/insect cells system but introduced significant improvements in the protocols for Dd expression and purification, leading to considerable savings in time and improved yield.

Oxidative stress as an early prognostic factor in acute pancreatitis (AP): its correlation with serum phospholipase A2 (PLA2) and plasma polymorphonuclear elastase (PMN-E) in different-severity forms of human AP.

The role of oxidative stress as an important pathogenetic factor in experimental AP is commonly accepted, but its role in human AP has still not been evaluated satisfactorily. In the present study we compared the parameters of oxidative stress to the level of PLA2 and PMN-E in patients with AP. The study was performed in 77 patients with mild (n = 31), moderate (n = 20), and severe (n = 26) AP (alcoholic and biliary) as assessed according to Ranson's and Balthazar's criteria. Serum and urine malondialdehyde (MDA) concentrations, as an index of oxidant-mediated lipid peroxidation, and sulfhydryl (SH) groups, a major nonenzymatic antioxidant, were measured along with serum PLA2 and plasma PMN-E at admission (day 0) and on days 2, 5, and 10 of the disease. The Serum MDA level in severe AP was elevated by 267% on day 0 and 230% after 10 days, in comparison to the control, by 104 and 105% in comparison to mild AP, and by 50 and 76% in comparison to moderate AP, respectively. This was accompanied by a decrease in serum SH groups by 23% on day 0 and 36% after 10 days, in comparison to the control, by 31 and 32% in comparison to mild AP, and by 20 and 11% (ns) in comparison to moderate AP, respectively. In all severity forms of AP, oxidative stress was proportionally accompanied by increased levels of PLA2 and plasma PMN-E. In conclusion, oxidative stress is an early phenomenon in patients with AP, and at the time of admission it is detectable in the serum and urine. The intensity of oxidative stress correlates with the severity of AP. Because of the significant correlation between MDA and PLA2 or PMN-E, we suppose that the parameters of oxidative stress may be useful as another early prognostic factor in human AP.

One week treatment with omeprazole, clarithromycin and tinidazole or lansoprazole, amoxicillin and metronidazole for cure of Helicobacter pylori infection in duodenal ulcer patients.

We defined optimal Helicobacter pylori (Hp) treatment as Hp eradication rate about 90%, well-tolerated with few side-effects. Two centers carried out randomized trials including 90 patients (74% men, 26% women, ages ranging from 18 to 65, mean age 42 +/- 8) with active duodenal ulcers (DU). Patients were treated with the combination of Omeprazole (O) 20 mg bd + Clarithromycin (C) 250 mg bd + Tinidazole (T) (500 mg bd) or with Lansoprazole (L) 15 mg bd + Amoxicillin (A) 750 mg bd + Metronidazole (M) 500 mg bd administered for one week. The DU healing rate was evaluated by endoscopy and the Hp status by rapid urease CLO-test and 14C-urea breath test (UBT). The healing rate of the DU in a group treated with the combination of O + C + T was 91% and in group treated with L + A + M was 93%. The eradication of Hp in group O + C + T and L + A + M averaged 91% and 87%, respectively. There was no statistically significant difference in the DU healing rate and the Hp eradication rate between these two groups. Both treatments were accompanied by a marked rise in the basal and postprandial plasma gastrin levels and the rise in the intragastric pH but these alterations returned to the pre-treatment values 4 weeks after the termination of the therapy. Both treatments were well tolerated and the only side effect was the taste disturbance observed in few patents treated with O + C + T. None of patients discontinued the treatment because of the adverse events. We conclude that one week treatment using O + C + T or L + A + M are highly and equally effective in the healing of DU and in the eradication of Hp.

Spinal epidural abscess: common symptoms of an emergency condition. A case report.

Spinal epidural abscess (SEA) is a severe pyogenic infection of the epidural space that leads to devastating neurological deficits and may be fatal. SEA is usually located in the thoracic and lumbar parts of the vertebral column and injures the spine by direct compression or local ischemia. Spinal injury may be prevented if surgical and medical interventions are implemented early. The diagnosis is difficult, because clinical symptoms are not specific and can mimic many benign conditions. The classical triad of symptoms includes back pain, fever and neurological deterioration. The gold standard in the diagnostic evaluation is magnetic resonance imaging with gadolinium enhancement, which determines the location and extent of the abscess. Increased awareness of the disease is essential for rapid recognition and immediate implementation of treatment. Here we describe the case of a 26-year-old woman with SEA with fever, back pain in the thoracic region and delayed symptoms of a transverse spinal cord injury.

Multifocal necrotizing fasciitis - case report.

PURPOSE: Necrotizing fasciitis (NF) is a rare, life-threatening soft-tissue infection, characterized by rapidly spreading inflammation, with secondary necrosis of the fascia and surrounding tissues. It is mostly caused by group A beta-haemolytic streptococci or multibacterial. A case of the 25-year-old man admitted on September 2006 to the Department of Dermatology and Venereology with suspicion of erysipelas of the left upper limb and left foot is presented. On admission the pain, erythema, diffuse oedema of the left upper limb and erythema of the left foot were observed. Laboratory results revealed elevated: ESR, acute phase parameters (C-reactive protein, D-dimer), CPK and fibrinogen. Within 72-hours, despite treatment with antibiotics and anticoagulants, the oedema and pain increased, initial necrosis of the skin and extreme local tenderness appeared. Suspecting NF the patient had been transported to the Department of Surgery from where, after surgical debridement of devitalized tissue, was moved to the Intensive Care Unit and then transferred to the National Centre of Hyperbaric Medicine of the Medical University of Gdansk. Despite of repeated debridement, aggressive antibiotic therapy and hyperbaric oxygen therapy, necrosis was spreading. The patient developed sepsis and acute respiratory distress syndrome. Amputation of the left upper limb was performed. Five months later patient was admitted to ICU in Bialystok after a suicide attempt. After next four months he died. The dramatic course of the disease is the evidence, that having an adequate knowledge about early symptoms of NF can save patient's life.