Bone morphogenetic protein-2 influence on metabolic activity and proteoglycan synthesis by intervertebral disc cells

Modern therapeutic strategies for intervertebral disc repair mainly focus on targeting molecular pathways of extracellular matrix degeneration. Anabolic strategies for regeneration are aimed to increase production of major extracellular molecules. Members of TGF-b superfamily proteins, particularly the bone morphogenetic proteins (BMP) have a high regenerative potential regarding the mesenchymal cells. The goal of this study is to study production of proteoglycans by the intervertebral disc cells under the influence of bone morphogenetic protein 2. Material and methods. The experiment was carried out on the cell cultures derived from the annulus fibrosis cells and nucleus pulposus cells of the human intervertebral disc. We studied cell livability, metabolic activity and proteoglycan expression. Cell livability was assessed using the trypan blue staining. Alamar blue test was used for the estimation of metabolic activity. Amount of sulfated glycosaminoglycans was assessed using the assay based on the reaction with 1,9-Dimethylmethylene Blue. Results. Cultivation with bone morphogenetic protein 2 in different concentrations did not decrease livability of the cells. Study cell cultures with application of bone morphogenetic protein 2 in different concentrations showed significant increase in metabolic activity and proteoglycan synthesis by the annulus fibrosis cells. Despite the relative increase in the number of the nucleus pulposus cells treated with the bone morphogenetic protein 2, the differences in metabolic and synthetic activity compared with control group was not significant. Conclusion. The bone morphogenetic protein 2 has an anabolic effect towards the intervertebral disc cells, particularly in the production of proteoglycans by the annulus fibrosis cells

General Stability Analysis of Synchronized Dynamics in Coupled Systems

We consider the stability of synchronized states (including equilibrium point, periodic orbit or chaotic attractor) in arbitrarily coupled dynamical systems (maps or ordinary differential equations). We develop a general approach, based on the master stability function and Gershgorin disc theory, to yield constraints on the coupling strengths to ensure the stability of synchronized dynamics. Systems with specific coupling schemes are used as examples to illustrate our general method.Comment: 8 pages, 1 figur

Microsurgical Treatment of Epidermoids. Case Report and Literature Review

The aim of the research: study the features of surgical treatment of epidermoids.Materials and methods. We present a literature review and the clinical case of surgical treatment of a patient with epidermoid. We have searched medical databases: Medline, Russian Science Citation Index, EMedicine, United Medical Knowledge Base. We considered the features of the clinic, diagnosis, and surgical intervention. The article presents a clinical example of successful surgical treatment of a patient with an epidermoid cyst of the posterior cranial fossa. The result of the literature review was the writing of a clinical lecture; the current state of the issue of etiopathogenesis, diagnosis and management of patients with epidermoids was studied.Results. The authors found that total microsurgical removal is the method of choice, and the operative technique should be aimed at preventing postoperative aseptic meningitis. Although it was not possible to establish the cause of the development of aseptic meningitis, the authors assume that the mechanism of its formation lies in the self-breaking of the capsule of the epidermoid cyst, probability of which was confirmed by a number of studies. Further study of this pathology is a promising direction in neurosurgery.Conclusion. Difficulties in the diagnosis and choice of surgical tactics point at the need for detailed preoperative planning of surgical intervention, performing a precise total removal of a lesion with compliance with preventive measures for aseptic meningitis to improve clinical results and reduce the incidence of perioperative complications

Modeling of Spiking-Bursting Neural Behavior Using Two-Dimensional Map

A simple model that replicates the dynamics of spiking and spiking-bursting activity of real biological neurons is proposed. The model is a two-dimensional map which contains one fast and one slow variable. The mechanisms behind generation of spikes, bursts of spikes, and restructuring of the map behavior are explained using phase portrait analysis. The dynamics of two coupled maps which model the behavior of two electrically coupled neurons is discussed. Synchronization regimes for spiking and bursting activity of these maps are studied as a function of coupling strength. It is demonstrated that the results of this model are in agreement with the synchronization of chaotic spiking-bursting behavior experimentally found in real biological neurons.Comment: 9 pages, 12 figure

NANOSTRUCTURAL ANALYSIS IN COMPARATIVE ESTIMATION OF DEGENERATIVE CHANGES IN INTERVERTEBRAL DISK

By atomic force microscopy we realized the research of anatomic material represented by the fragments of tissue of intervertebral disks of different stages of degenerative process. The researches were carried out with help of probe nanolaboratory with videomicroscope Ntegra Prima. As the result we obtained direct experimental data that proves some theoretical investigation that hadn't had. visual proves

Plankton lattices and the role of chaos in plankton patchiness

Spatiotemporal and interspecies irregularities in planktonic populations have been widely observed. Much research into the drivers of such plankton patches has been initiated over the past few decades but only recently have the dynamics of the interacting patches themselves been considered. We take a coupled lattice approach to model continuous-in-time plankton patch dynamics, as opposed to the more common continuum type reaction-diffusion-advection model, because it potentially offers a broader scope of application and numerical study with relative ease. We show that nonsynchronous plankton patch dynamics (the discrete analog of spatiotemporal irregularity) arise quite naturally for patches whose underlying dynamics are chaotic. However, we also observe that for parameters in a neighborhood of the chaotic regime, smooth generalized synchronization of nonidentical patches is more readily supported which reduces the incidence of distinct patchiness. We demonstrate that simply associating the coupling strength with measurements of (effective) turbulent diffusivity results in a realistic critical length of the order of 100 km, above which one would expect to observe unsynchronized behavior. It is likely that this estimate of critical length may be reduced by a more exact interpretation of coupling in turbulent flows

Synchronous bursts on scale-free neuronal networks with attractive and repulsive coupling

This paper investigates the dependence of synchronization transitions of bursting oscillations on the information transmission delay over scale-free neuronal networks with attractive and repulsive coupling. It is shown that for both types of coupling, the delay always plays a subtle role in either promoting or impairing synchronization. In particular, depending on the inherent oscillation period of individual neurons, regions of irregular and regular propagating excitatory fronts appear intermittently as the delay increases. These delay-induced synchronization transitions are manifested as well-expressed minima in the measure for spatiotemporal synchrony. For attractive coupling, the minima appear at every integer multiple of the average oscillation period, while for the repulsive coupling, they appear at every odd multiple of the half of the average oscillation period. The obtained results are robust to the variations of the dynamics of individual neurons, the system size, and the neuronal firing type. Hence, they can be used to characterize attractively or repulsively coupled scale-free neuronal networks with delays.Comment: 15 pages, 9 figures; accepted for publication in PLoS ONE [related work available at http://arxiv.org/abs/0907.4961 and http://www.matjazperc.com/

Rapid ecological change in the coastal zone of Lake Baikal (East Siberia): Is the site of the world\u27s greatest freshwater biodiversity in danger?

Ecological degradation of the benthic littoral zone is an emerging, urgent problem at Lake Baikal (East Siberia), the most species-rich lake on Earth. Within the last five years, multiple changes have occurred in the nearshore benthos where most of the lake\u27s endemic species reside. These changes include proliferation of benthic algae, deaths of snails and endemic sponges, large coastal wash-ups of dead benthic algae and macrophytes, blooms of toxin-producing benthic cyanobacteria, and inputs of industrial contaminants into parts of the lake. Some changes, such as massive coastal accumulations of benthic algae, are currently shared with the Laurentian Great Lakes (LGLs); however, the drivers of these changes differ between Lake Baikal and the LGLs. Coastal eutrophication from inputs of untreated sewage is causing problems at multiple sites in Lake Baikal, whereas in the LGLs, invasive dreissenid mussels redirect pelagic nutrients to the littoral substrate. At other locations in Lake Baikal, ecological degradation may have different causes including water level fluctuations and the input of toxic industrial contaminants. Importantly, the recent deterioration of the benthic littoral zone in both Lake Baikal and the LGLs has occurred while little change has occurred offshore. This highlights the necessity of monitoring both the littoral and pelagic zones of large lakes for assessing ecosystem health, change and conservation