CD55 is a HIF-2α marker with anti-adhesive and pro-invading properties in neuroblastoma.

CD55 has been revealed to have an important role in tumor genesis, and presence of small populations of cells with strong CD55 expression would be sufficient to predict poor prognosis of several tumors. In our study we revealed that CD55 is a novel target of hypoxia-inducible factor HIF-2α in neuroblastoma (NB) cells. We show that HIF-2α expression is sufficient to sustain stem-like features of NB cells, whereas CD55 protein upon HIF-2α expression contributes to growth of colonies and to invasion of cells, but not to stemness features. Interestingly, in NB tissues, CD55 expression is limited to quite a small population of cells that are HIF-2α positive, and the gene expression of CD55 in the NB data set reveals that the presence of CD55(high) affects prognosis of NB patients. The functional characterization of CD55-positive populations within heterogeneous NB monoclonal cell lines shows that CD55 has pro-invading and anti-adhesive properties that might provide the basis for the ability of solid tumors to survive as microscopic residual disease. The easy accessibility to CD55 membrane antigen will offer the possibility of a novel antibody approach in the treatment of recurrent tumors and will provide a ready target for antibody-based visualization in NB diagnosis and prognosis.

Alpha-lipoic acid modulates GFAP, vimentin, nestin, cyclin D1 and MAP-kinase expression in astroglial cell cultures.

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.

Novel inhibitors of neuronal nitric oxide synthase.

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]-1H-imidazoles as interesting molecules for their selectivity for nNOS against eNOS. This work reports a new series of 1-[(Aryloxy)alkyl]-1H-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 (BH(4)) binding site of nNOS, without interference with any other cofactors or substrate binding sites.

GFAP, S-100 and vimentin proteins in rat after cerebral post-ischemic reperfusion.

In the present study astrocytes reactivity during cerebral post-ischemic reperfusion was evaluated immunocytochemically by using antibodies to vimentin, glial fibrillary acidic protein (GFAP) and S-100 protein. At the 7th day of post-ischemic reperfusion few GFAP-positive cells were observed in the hippocampus and cerebellum, the number of GFAP-positive cells increased slightly after 20 days of reperfusion. This poor GFAP-positivity may be due to the inhibition of GFAP polymerization by S-100; in fact, S-100 immuno-reactivity was already evident from the 7th day. Vimentin immuno-staining was evident both at the 7th and 20th day of reperfusion in microglial cells and in oligodendrocytes, suggesting that these cells are involved in the recovery of neurons following brain injury.

[Calcium release from the mineral matrix of the mandibular bone due to hydrogen peroxide exposure]. / Rilascio di calcio della matrice minerale di osso mandibolare mediante esposizione a perossido di idrogeno.

The purpose of this paper is to quantify by in vitro experiment free radical activity in jaw bone demineralization processes. Sample were take and graphic interpolation of calcium ions undertake. The significance of the results is compared with the paper that are published in literature on the same subject.

[A polymorphism study of the DNA extracted from dental tissues]. / Studio di polimorfismi del DNA estratto da tessuti dentari.

Often teeth are the only items which can be used for personal identification in forensic medicine. In the present work we describe a method to extract and amplify DNA from dental elements ranging from 2 weeks to 5 year from the avulsion. PCR (polymerase chain reaction) was used to amplify VNTR sequences; the alleles products were electrophoresed, visualized by traditional methods and compared to the amplified products obtained from the matching blood sample. Our results give a new and powerful investigative tool for personal identification in the field of forensic odontostomatology, since such a procedure can be successfully applied both to recent and to ancient teeth.

[DNA extraction from hard dental tissues]. / Estrazione di DNA dai tessuti duri del dente.

Two different standard ways of DNA extraction (salting out and phenol-chloroform methods) were assayed in order to recovery nucleic acids from dental tissues. The DNA extracted was tested for purity by means of transverse alternating field electrophoresis (TAFE) using Saccharomyces cerevisiae chromosomes as markers. Both extraction methods give similar qualitative and quantitative results being a DNA yield from hard dental tissues approximately 30% of those extracted from the whole tooth. Our results indicate salting out as a preferable method due to its rapidity and usefulness.

Influence of different counterions on the fluorescent probe-DNA complex.

Studies carried out on both linear and covalently closed DNA have clearly revealed at least two different types of probe-DNA complexes depending on the different experimental procedure adopted, and two main types of binding of the probe have been clearly established and referred to as intercalative and external binding. In order to investigate the influences of the different counterions on the stability of the probe-DNA complex, a set of static fluorimetric measurements were performed in a wide range of concentrations (1 mM to 2 M) of different alkaline-earth chlorides. At low salt concentrations (in the range of millimolar values) no detectable fluorescence intensity changes were evidenced by the use of alkaline salts, but a marked decrease was detected by using alkaline-earth salts. The present work investigates moreover the role played by the different salt, in first place Calcium salts, on the stability of ethidium-DNA complex, by the use of the static fluorimetric titration procedure which is able to discriminate between the two strong and weak binding sites on DNA. Our experimental results have been interpreted in terms of a peculiar Calcium-DNA interaction, involving not only the electrostatic charges of phosphate moiety but also the aromatic rings of the bases, i.e., the intercalation sites on double helix DNA.

[Correlation between serum glutathione reductases and bone densitometry values]. / Correlazione tra glutatione-reduttasi serica e valori densitometrici ossei.

Free radicals, because of their marked chemical activity, have often been found to be involved in many human diseases. Enzymatic antioxidant systems, namely glutathione-reductase, present both in red blood cells and in serum, have been demonstrated to play a key role as free radicals scavengers. The present work has been carried out in order to evaluate the possible role played by free radicals in the demineralization process of the bone matrix. Glutathione-reductase activity, assayed by a slightly modified Horn's method, was related to bone density measurements. All the subjects with reduced densitometric values showed reduced glutathione-reductase levels. Our results seem to support the hypothesis of a strict relationship between low activity of antioxidant systems and demineralization process of the bone, in consequence of enhanced free radical levels.

[Study of pollen of allergologic significance in the urban atmosphere of Parma in the years 1983-1984]. / Studio di alcuni pollini di interesse allergologico nell'atmosfera urbana di Parma negli anni 1983-1984.

From 1983 to 1984 pollen air samples from Parma's urban atmosphere were collected weekly by means of a Burkard recording volumetric spore trap. Data regarding a few of the meteorologic variables were also collected at the same time: temperature, insulation, water precipitation, humidity and wind speed. Some of the more allergenic pollens and their concentration/m3 air were determined from the collected samples: Graminea, Urticaceae, Fagaceae, Salicaceae and Betulaceae. Looking at the results from the period of study, it can be seen that Graminea and Urticaceae were the most represented in comparison with the other families. Graminea was most represented in May 1983, in June 1984 and during the first week of September 1984; Urticaceae in September 1983, May 1984 and September 1984. These pollen concentrations were also compared to the meteorologic data.

DNA-4'-6-diamidine-2-phenylindole interactions: a comparative study employing fluorescence and ultraviolet spectroscopy.

DAPI is a drug that interacts with double-stranded nucleic acids, binding preferentially to A + T base pairs. The interaction is not intercalative, therefore providing a useful model for mimicking the effect of functional molecules in modifying specific sites, namely, A + T segments, of significance in gene expression. Knowledge of the nature of such interaction has been enriched by additional information obtained from comparative analysis of the data acquired by uv spectroscopy and fluorescence. Two classes of binding sites, defined by different apparent affinity constants and numbers of binding sites, are evident. All types of interaction are dependent on the nucleic acid/dye ratio and on the ionic strength of the medium.

Interaction of papaverine with covalently closed DNA.

Cyclic nucleotides influence viral replication and papaverine, as an inhibitor of phosphodiesterase, also affects the replication of both DNA and RNA viruses through an increase in cAMP levels. Moreover in vitro papaverine affects neither protein synthesis nor several polymerases, while it inhibits DNA synthesis. Static fluorescence studies on the interaction of the drug with ColE1 plasmid covalently closed DNA indicate that the drug binds to the nucleic acid, probably by intercalation. A comparison between the binding characteristics of Papaverine and Actinomycin D is also reported.

Interaction of diamidino-2-phenylindole (DAPI) with natural and synthetic nucleic acids.

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.

Effect of undernutrition on some enzymes involved in the salvage pathway of purine nucleotides in different regions of developing rat brain.

The effect of undernutrition on the activity of two key enzymes of purine salvage pathway, namely hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) and adenine phosphoribosyltransferase (APRTase), in cerebral hemispheres, cerebellum and brain stem of rats at different days of postnatal development was studied. The activity of HGPRTase and of APRTase is significantly lower in all brain regions of undernourished animals at 5 days after birth; between 10 and 15 days of age there is a recovery of the enzymatic activity which is particularly evident in the cerebellum. Successively both enzymatic activities decrease reaching at 30 days of age values quite similar to those of controls. These results indicate that undernutrition during fetal and postnatal development, impairs and delays the activity of the enzymes of purine salvage pathway.

Effect of undernutrition on some enzymes of purine metabolism in different regions of developing rat brain.

The effect of undernutrition on the activity of some enzymes involved in purine metabolism, ie, adenosine aminohydrolase, adenylate aminohydrolase, and inosine phosphorylase in cerebral hemispheres, cerebellum, and brain stem of rats at different days of postnatal development was studied. Adenosine aminohydrolase, adenylate aminohydrolase, and inosine phosphorylase were assayed by radiochemical methods which involve the measurement of the radioactive products formed, ie, inosine, IMP, and hypoxanthine, respectively. The results obtained indicate that undernutrition affects the activity of the enzymes which control the concentration of purine nucleotides to a different degree in the three brain regions examined.

De novo biosynthesis of nucleotides and of nucleic acids in different regions of developing rat brain: effect of undernutrition.

The effect of undernutrition on the de novo biosynthesis of nucleic acids in cerebral hemispheres, cerebellum, and brain stem of rats at different days of postnatal development was studied. The experiments were carried out in vitro by measuring the incorporation of [14C]-formate into the adenine nucleotide of the acid-soluble fraction of RNA and DNA, as well as into the thymine of DNA. The results obtained indicate that undernutrition during fetal and postnatal development impairs the de novo synthesis of the purine nucleotides of RNA and DNA at 5 days of age and delays it thereafter in the various brain regions examined, particularly in the cerebellum.