D. P. Ivanov

Transgenic inhibition of astroglial NF-κB protects from optic nerve damage and retinal ganglion cell loss in experimental optic neuritis.

BackgroundOptic neuritis is an acute, demyelinating neuropathy of the optic nerve often representing the first appreciable symptom of multiple sclerosis. Wallerian degeneration of irreversibly damaged optic nerve axons leads to death of retinal ganglion cells, which is the cause of permanent visual impairment. Although the specific mechanisms responsible for triggering these events are unknown, it has been suggested that a key pathological factor is the activation of immune-inflammatory processes secondary to leukocyte infiltration. However, to date, there is no conclusive evidence to support such a causal role for infiltrating peripheral immune cells in the etiopathology of optic neuritis.MethodsTo dissect the contribution of the peripheral immune-inflammatory response versus the CNS-specific inflammatory response in the development of optic neuritis, we analyzed optic nerve and retinal ganglion cells pathology in wild-type and GFAP-IκBα-dn transgenic mice, where NF-κB is selectively inactivated in astrocytes, following induction of EAE.ResultsWe found that, in wild-type mice, axonal demyelination in the optic nerve occurred as early as 8 days post induction of EAE, prior to the earliest signs of leukocyte infiltration (20 days post induction). On the contrary, GFAP-IκBα-dn mice were significantly protected and showed a nearly complete prevention of axonal demyelination, as well as a drastic attenuation in retinal ganglion cell death. This correlated with a decrease in the expression of pro-inflammatory cytokines, chemokines, adhesion molecules, as well as a prevention of NAD(P)H oxidase subunit upregulation.ConclusionsOur results provide evidence that astrocytes, not infiltrating immune cells, play a key role in the development of optic neuritis and that astrocyte-mediated neurotoxicity is dependent on activation of a transcriptional program regulated by NF-κB. Hence, interventions targeting the NF-κB transcription factor in astroglia may be of therapeutic value in the treatment of optic neuritis associated with multiple sclerosis.

Mechanism of Coke Influence on the Catalytic Activity of FeZSM-5 in the Reaction of Benzene Oxidation into Phenol

The influence of coke formation in the reaction of benzene oxidation by nitrous oxide into phenol on the catalytic activity and concentration of iron-containing active sites (α-sites), which are stabilized in the microporous structure of FeZSM-5 zeolite, is studied. The deactivation by coke is explained by the poisoning of α-sites, whose concentration decreases linearly with an increase in the coke content, rather than by the blocking of zeolite pores. The activity per one α-site remains unchanged. This fact indicates the absence of diffusion limitations associated with coke formation. The toxicity of coke for the α-sites is determined. The coke amount equivalent to 100–120 benzene molecules is shown to result in the deactivation of one active site.

New Way of Hydroquinone and Catechol Synthesis using Nitrous Oxide as Oxidant

The synthesis of dihydroxybenzenes (DHB) via the gas-phase oxidation of phenol with nitrous oxide in the presence of benzene was studied. Addition of benzene to the feed mixture greatly improves the selectivity and catalytic stability of the Fe-containing ZSM-5 zeolite, that was previously considered to be a main obstacle to the development of a new process. Reaction conditions strongly affect the distribution of the DHB isomers: the ratio of hydroquinone to catechol may vary from 1.4 to 10, with the resorcinol fraction being nearly constant and comprising 3 ± 5%. Some 40h experiments on the oxidation of a phenol-benzene mixture demonstrated the high efficiency of the formed FeZSM-5 catalyst. With a good stability, the catalyst provides 97% phenol selectivity referred to DHB and 85 ± 90% N2O selectivity referred to the sum of DHBs and phenol. A new process for hydroquinone and catechol synthesis based on the neat oxidation of benzene with recycling of the phenol as an intermediate product is suggested.

Use of carbon–oligomer filler prepared from rubbers reclaimed with dinitrogen monoxide as a component of elastomer compounds

Samples of carbon–oligomer filler prepared by ketonization of tire rubber crumb with dinitrogen monoxide were characterized. The effect of the oligomeric component of the filler on the kinetic parameters of cross-linking in model compounds was determined. A study of the main rheological and physicomechanical properties of elastomer compounds based on butadiene–α-methylstyrene rubber containing carbon–oligomer filler demonstrated the possibility of using it as a component of polyfunctional action.

Interaction of Nylon Cord with a Polymer—Oligomer—Solvent System

The interphase interaction of nylon cord 23RYNC with a polymer—oligomer—solvent system was investigated in order to predict the properties of resin—cord composites. It was found that functional oligodienes at the fiber—polymer interface formed a transition layer with the packing density required to produce items with few defects.

THE M813 RETROVIRUS BELONGS TO A UNIQUE INTERFERENCE GROUP AND IS HIGHLY FUSOGENIC

Retroviral vectors are powerful tools for genetic analysis of stem cells and their progenitors. They have been used both as gene vectors, to both up or down regulate gene expression - as well as mutagens, to identify genes modulating a specific phenotype. Furthermore, their importance in the clinic is currently being tested in several on-going gene therapy trials. Understanding the basic biology of retrovirus is tantamount to developing efficacious tools for the laboratory and the clinic. Here we summarize the characterization of a novel γ-retrovirus isolate from feral mice. The M813 isolate was shown to have a unique host range and belong to a novel interference group. Our analysis also revealed the highly fusogenic potential of this virus. Finally, we were able to identify the sodium myo-inositol transporter as its receptor. The unique characteristics of this viral isolate open several venues for the development of novel research tools.