The interaction of DAPI with natural and synthetic polydeoxynucleotides of different base content and sequences was studied with circular dichroism, ultracentrifugation, viscosity and calorimetry. All the polymers show two types of binding. The strength of the interaction and its resistance to ionic strength are related to the content of AT clusters in the chain. On the other hand, sedimentation measurements rule out an intercalation mechanism. A model of DAPI interaction with DNA, similar to that displayed by distamycin and netropsin, is proposed.

In the present study, we evaluated the expression of some proliferation and differentiation markers in 15 DIV astrocyte cultures pretreated or not with 0.5 mM glutamate for 24 h and than maintained under chronic or acute treatment with 50 μM R(+)enantiomer or raceme alpha-lipoic acid (ALA). GFAP expression significantly increased after (R+)enantiomer acute-treatment and also in glutamate-pretreated ones. Vimentin expression increased after R(+)enantiomer acute-treatment, but it decreased after raceme acute-treatment. Nestin expression drastically increased after acute raceme-treatment in glutamate-pretreated or not cultures, but significantly decreased after (R+)enantiomer acute and chronic-treatments. Cyclin D1 expression increased in raceme acute-treated cultures pretreated with glutamate. MAP-kinase expression slightly increased after (R+)enantiomer acute treatment in glutamate-pretreated or unpretreated ones. These preliminary findings may better clarify antioxidant and metabolic role played by ALA in proliferating and differentiating astrocyte cultures suggesting an interactive cross-talk between glial and neuronal cells, after brain lesions or damages.

The two major intermediate filament (IF) proteins of astrocytes are vimentin and GFAP. Early during development, radial glia and immature astrocytes express mainly vimentin. Towards the end of gestation, a switch occurs whereby vimentin is progressively replaced by GFAP in differentiated astroglial cells. The expression of vimentin and GFAP increased markedly after injury to CNS. GFAP has been widely recognized as an astrocyte differentiation marker, constituting the major IF protein of mature astrocyte. In our recent researches we investigated the interactions between growth factors and dexamethasone on cytoskeletal proteins GFAP and vimentin expression under different experimental conditions. In addition, nestin, a currently used marker of neural stem cells, is transiently co-expressed with GFAP during development and is induced in reactive astrocytes following brain injury. The role of S100B in astrocytes, neurons, and microglia is particularly studied in Alzheimer's disease. In conclusion, such glial biomarkers will help us to understand the more general mechanisms involved in CNS development and can open new perspectives for the control of the neurologic diseases.

Astroglial conditioned media (ACM) influence the development and maturation of cultured nerve cells and modulate neuron-glia interaction. To clarify mechanisms of astroglial cell proliferation/differentiation in culture, incorporation of [methyl-3H]-thymidine or [5,6-3H]-uridine in cultured astrocytes was assessed. Cultures were pre-treated with epidermal growth factor (EGF), insulin (INS), insulin-like growth factor-I (IGF-I), and basic fibroblast growth factor (bFGF) and subsequently with ACM. DNA labeling revealed a marked stimulatory effect of ACM from 15 days in vitro (DIV) cultures in 30 DIV astrocytes after 12 h pre-treatment with growth factors. The main effects were found after INS or EGF pre-treatment in 30 DIV cultures. ACM collected from 15 or 60 or 90 DIV increased RNA labeling of 15 and 30 DIV astrocyte cultures, being the highest value that of 30 DIV cultures added with ACM from 90 DIV. The findings of increased DNA labeling after EGF or INS pre-treatment in 30 DIV cultures, followed by addition of ACM from 15 DIV cultures, suggest that these phenomena may depend by extra cellular signal-regulated kinase 1 (ERK1) activation.

No abstract

In this research we aimed to investigate the interactions between growth factors (GFs) and dexamethasone (DEX) on cytoskeletal proteins GFAP and vimentin (VIM) expression under different experimental conditions. Condition I: 24 h pretreatment with bFGF, subsequent 72 h switching in serum-free medium (SFM) and final addition of GFs, alone or by two in the last 24 h, after a prolonged (60 h) DEX treatment. Condition II: 36 h pretreatment with DEX (with bFGF in the last 24 h), followed by SFM for 60 h and final addition for 24 h with growth factors alone or two of them together. Western blot analysis data showed a marked GFAP expression in cultures submitted to Condition I comparing results to untreated or treated controls. VIM expression was instead significantly reduced after GFs addition in the last 24 h of 60 h DEX treatment, respect to control DEX-pretreated ones. Referring data to untreated controls, VIM expression was significantly enhanced after GFs addition. GFAP showed also a significant increase in astrocytes submitted to Condition II, respect to untreated or treated control cultures. VIM expression was up and down regulated under Condition II. Collectively, our findings evidence an interactive dialogue between GFs and DEX in astroglial cultures, co-pretreated with DEX and bFGF, regulating cytoskeletal network under stressful conditions.

The major natural polyphenols of wine are flavonoids. Red wine also contains a natural phytoalexin called resveratrol which recently has been the subject of conflicting reports regarding its protective role against cardiovascular diseases.We have investigated the free radical scavenging capacity of resveratrol, its effects on xanthine oxidase (XO) activity, spontaneous membrane lipid oxidation, and DNA cleavage. Resveratrol showed a dosedependent free radical scavenging activity, significant inhibition of XO activity, an anti-lipoperoxidative capacity, and a protective effect on DNA cleavage. The antioxidant capacity of resveratrol is ascribed to the concomitant activities of scavenging free radicals, metal chelating, and inhibition of some enzymes involved in free radical generation.

Selective inhibitors of neuronal nitric oxide synthase (nNOS), which are devoid of any effect on the endothelial isoform (eNOS), may be required for the treatment of some neurological disorders. In our search for novel nNOS inhibitors, we recently described some 1-[(Aryloxy)ethyl]-1 H-imidazoles as interesting molecules for their selectivity for nNOS against eNOS. This work reports a new series of 1-[(Aryloxy)alkyl]-1 H-imidazoles in which a longer methylene chain is present between the imidazole and the phenol part of molecule. Some of these molecules were found to be more potent nNOS inhibitors than the parent ethylenic compounds, although this increase in potency resulted in a partial loss of selectivity. The most interesting compound was investigated to establish its mechanism of action and was found to interact with the tetrahydrobiopterin (BH4) binding site of nNOS, without interference with any other cofactors or substrate binding sites.