[Objectivity regarding stress: looking the past, evaluating the present...a chance in the future]. / Obiettivare lo stress: uno sguardo al passato, valutando il presente...una scommessa per il futuro.

To objective the stress is extremely arduous, but it's very important. Stress is an answer of human to frequent and particularly not lovely events. Cohen said: "the stress is the experience of negative events or the perceptions of distress and negative affect that are associated with the inability to cope with them". We investigated the stress using double approach i)psycho-diagnostic test able to show psychological effects ii) kit test able to measure salivary markers of stress as Cortisol and Interleukin 1 Beta (ILl Beta). The former indicates alterations of neuroendocrine system, the second permits us to determinate variation on cytokines balance particularly between cytokines pro-inflammatory and cytokines anti-inflammatory. This balance is strategic in several disease like cancer, infective, autoimmune and allergic diseases. Our salivary determinations show the cortisol means and the standard deviations are similar, that's denotes great variability, about IL1 Beta we observed the same. We retain that salivary markers are very useful if we consider the difference between the antemeridian and post meridian value in the same subject, indeed it correlates with possible diseases. The study of HRV (Heart Rate Variability) is used to monitor the Autonomic Nervous System, in our experience the HRV parameters during the work resulted useful as confront, instead the HRV parameters during the holiday resulted surest indexes of work stress. Probably the effect of stress on the heart aren't present during the work because the work experience reduces these effects, they appear during the holiday when the imagination could make the conflicts or the problems more complex than they are, that's not true using salivary markers.

Role of tumour necrosis factor alpha and interleukin 1 beta in promoter effect induced by mercury in human keratinocytes.

In the progress of a carcinogenetic process, the promoter effect was seen as the final event able to determine uncontrolled proliferation. The promoter effect begins with an inhibition of gap junctional intercellular communication. Previously we observed an inhibitory effect of Mercury (HgCl2) on Gap Junction Intercellular Communication of Human Keratinocytes in culture. Here we evaluate the effect of Mercury on gap junctional intercellular communication, on cytokines intracellular concentrations and on cytokines secretion of Human Keratinocytes. In particular, we report a reduction of the intracellular concentrations and secretions of Tumour Necrosis alpha and Interleukin 1 beta. It is known that the inhibitory effect on Gap Junctional Intercellular Communication is correlated with a promoter effect induced by carcinogens. In this paper we discuss the relationship between the inhibition of gap junctional intercellular communication and cytokine production, and whether these effects are related in an xenobiotic carcinogenesis process. Our considerations could be seen as too adventurous, but they may set the stage for an open discussion of our results according to the literature. An intriguing relationship appears to develop when comparing the effects of proinflammatory mediators on GJIC. Although highly speculative, a review of the current literature would suggest that the GJIC inhibition induced by mercury might be the beginning of the promoter effect, but the role induced by cytokines on initiated cells to stimulate its proliferation remains to be determined We think that the reduction of TNF-alpha, and in part IL-1beta, induced by mercury might favour the cancer. We hypothesise that the reduction of cytokines and inhibition of the gap junction intercellular communication are correlated and they may play a role in the xenobiotic carcinogenesis process.

The study of gap junctional intercellular communication in keratinocytes as screening of promoter effect induced by industrial and environmental toxic substances.

BACKGROUND: Disordered functioning of gap junctions between normal and initiated cells has been proposed as one possible mechanism of tumour promotion. Many putative carcinogens such as peroxisome proliferators, are known to activate various signal transduction mechanisms and modulate gap junctional intercellular communication (GJIC). They act as tumour promoters on pre-existing "initiated" cells, rather than as genotoxic initiators. OBJECTIVES: The aim of this article is to provide a screening-tool to evaluate the promoter carcinogen effect of environmental and occupational chemical contaminants, focusing on their ability to alter GJIC. METHODS: GJIC was investigated in serum-free cultured primary human keratinocytes, by directly evaluating the intercellular transfer of a microinjected fluorescent dye (Dye transfer). The expression of caspase 3, which is the ultimate target to be activated of both mitochondrial- and non-mitochondrial-linked pro-apoptotic pathways, was evaluated using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). RESULTS: Mercury chloride (10 nM), mono-methyl Mercury (250 nM) and Trichloroethylene (500 I1M) were shown to significantly inhibit GJIC. Conversely di-methyl mercury, lead acetate and epichloridine had no effect on GJIC. All Trans Retinoic Acid completely reversed the inhibitory effect on GJIC induced by HgCI2 but not that induced by mono-methyl mercury and trichloroethylene. The result of a RT-PCR assay on total RNA cell extract showed that treatment of keratinocytes with 10 nM HgCl2 resulted in a decrease of the pro-apoptotic caspase 3 expression. CONCLUSIONS: In this work a protocol is designed to study gap junction intercellular communication in primary cultures of human keratinocytes which could be used as a reliable screening tool to test the promoter carcinogen effect of various environmental and occupational contaminants.

[Oxidative stress in station service workers]. / Valutazione degli indici di stress ossidativo in addetti alla distribuzione del carburante.

INTRODUCTION: The aim of this study is to identify an oxidative stress in service station workers. Previous studies verified an increased incidence of leukemia and myeloma, however other authors haven't verified it. There are reports of nasal, pharyngeal, laryngeal, and lung cancer in service station workers. Our study wants to evaluate the oxidative balance in the fuel workers. MATERIAL AND METHODS: We studied 44 subjects with gasoline exposure and 29 control subjects. We determined the blood concentrations of Glutathione reduced and oxidized, Protein sulfhydrylic (PSH) Vitamine E, Vitamine C, Malondialdehyde, Protein oxidized (OX-PROT) and beta carotene. The t test was performed to analyze the differences between the means, the Chi square was used to evaluate the statistical significance of associations between variable categorical (redox index). The Anova test excluded the confusing effect of age, smoke and alcohol habit. RESULTS: The mean age of the workers was 36.6 years, instead the control group was 38. In the workers Glutathione reduced, Vit. E and Beta carotene were lower than in the control subjects, this difference was statistically significant (p < 0.01). The Malondialdehyde concentration was higher in the workers higher than in the control group, but this difference wasn't statistically significant. DISCUSSION AND CONCLUSIONS: Our data demonstrated Glutathione, Vit. E, and Beta carotene are useful to verify a reduction of the antioxidant activity. The only marker of the presence of oxidative injury that correlated to work exposure was the malondialdehyde. The redox index was surest marker. The limit of our study is the number of control group, it was little and lower than workers. Conclusively we believe it's useful to continue our studies and, if our results are going to be confirmed, we retain that stress oxidative determination would be verified in occupational medicine using these markers, especially to study exposure of the fuel workers who were investigated less and, in our opinion, would receive more attention.

[Promoter effect of mercury chloride and methyl-mercury on human keratinocytes in culture]. / Effetto promoter del mercurio cloruro e del metil-mercurio su cheratinociti umani in coltura.

Mercury has received considerable media focus because it is present in dental amalgams and seafood. There is potential exposure in gas meters, thermometers and fluorescent lamps workers. To evaluate its possible epigenetic carcinogen effect, cultures of human keratinocytes were treated with increasing doses of HgCl2 for 30 min, 24 h and of CH3HgCl for 24 h, respectively. The red neutral method was used to evaluate the doses of HgCl2 and CH3HgCl which had no cytotoxic effect. Then, the dye transfer method was used to investigate the gap junctions-mediated intercellular communication (GJIC). Cells were microinjected with Lucifer Yellow CH by using the Eppendorf Apparatus and the Leica inverted microscope. After 30 min incubation at the concentration of 10 microM, HgCl2 did not exert inhibition of GJIC. Conversely, after 24 h at the concentration of 10 nM, HgCl2 inhibited GJIC. Incubation with CH3HgCl at the concentration of 250 nM for 24 h reduced the number of fluorescent cells, thus denoting a inhibition of GJIC. Taken together our data demonstrated that: i) HgCl2 and CH3HgCl exerted an inhibitory effect upon GJIC; ii) HgCl2 resulted to inhibit GJIC at concentrations 25 folds lower than CH3HgCl. Further studies will be addressed to evaluate whether the reversal of GJIC inhibition could be obtained by withdrawal of toxic substance, or by the addition of a GJIC activator like the retinoic acid. Finally to shed light on the possible effect of mercury derivates at the transcriptional or translational levels, the expression profile of the connexin 43 gene after HgCl2 and CH3HgCl exposure of cultured human keratinocytes will be investigated.

Toxicity of fungicides containing ethylene-bis-dithiocarbamate in serumless dissociated mesencephalic-striatal primary coculture.

Agricultural exposure to the organomanganese fungicide MANEB (manganese-ethylene-bis-dithiocarbamate) may induce an extrapyramidal syndrome resembling parkinsonism. To evaluate the relative role of manganese (Mn) and ethylene-bis-dithiocarbamate (EBDTC) in the hazard of organomanganese fungicides, we studied the effects of MANCOZEB (Mn-Zinc-EBDTC) and ZINEB (Zinc-EBDTC) on serumless dissociated mesencephalic-striatal primary coculture. High affinity 3H-dopamine (DA) and 14C GABA uptakes as well as immunocytochemical staining of tyrosine hydroxylase (TH)-containing cells were used as specific functional markers of DA and GABA neuron viability. Both MANCOZEB and ZINEB, at 10 and 50 microM concentrations, dose dependently reduced DA and GABA viability parameters. These data suggest that EBDTC rather than Mn may be primarily responsible for the cytotoxicity of organomanganese fungicides on neuronal systems relevant to the pathophysiology of parkinsonism.