Safety of an accelerated build-up phase with pollen allergoids: a retrospective study

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The dynamics of myogenin site-specific demethylation is strongly correlated with its expression and with muscle differentiation.

The molecular mechanisms underlying the activation of tissue-specific genes have not yet been fully clarified. We analyzed the methylation status of specific CCGG sites in the 5'-flanking region and exon 1 of myogenin gene, a very important myogenic differentiation factor. We demonstrated a loss of methylation, at the onset of C2C12 muscle cell line differentiation, limited to the CCGG site of myogenin 5'-flanking region, which was strongly correlated with the transcriptional activation of this gene and with myogenic differentiation. The same CCGG site was also found to be hypomethylated, in vivo, in embryonic mouse muscle (a myogenin-expressing tissue), as opposed to nonmuscle (nonexpressing) tissues that had a fully methylated site. In a C2C12-derived clone with enhanced myogenic ability, demethylation occurred within 2 h of induction of differentiation, suggesting the involvement of some active demethylation mechanism(s) that occur in the absence of DNA replication. Exposure to drugs that inhibit DNA methylation by acting on the S-adenosylmethionine metabolism produced a further reduction, to a few minutes, in the duration of the demethylation dynamics. These effects suggest that the final site-specific DNA methylation pattern of tissue-specific genes is defined through a continuous, relatively fast interplay between active DNA demethylation and re-methylation mechanisms.

Transforming growth-factor-alpha modulates replication and differentiation markers on a human neuroblastoma cell-line.

The effects of TGF alpha and EGF on a human neuroblastoma cell line expressing EGF receptor were studied. Both growth factors were mitogenic for neuroblastoma and, at the same time, induced a morphological differentiation. TGF alpha treatment (10 ng/ml) determined an increase in the expression of laminin and neurofilaments, both markers typical of neuronal phenotype. Hovewer, unlike the differentiation induced by retinoic acid treatment, TGF alpha modulation of neuroblastoma neuronal markers was not mediated by an increase in the expression of the ret oncogene. Moreover, TGF alpha appeared to stimulate an autocrine production of TGF alpha itself, as evaluated by an increase in mRNA at three days of treatment. These data suggest a possible involvement of EGF and TGF alpha in a paracrine and autocrine control of neuroblastoma, possibly each accomplishing similar but complementary functions.

[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.