[Solar ultraviolet radiation risk in outdoor workers: a specific project of Tuscany Region (Italy)]. / Rischio da radiazione solare ultravioletta nei lavoratori outdoor: piano mirato della Regione Toscana.

OBJECTIVE: The aims of Tuscany Regional project were: to study the sun protection attitude of outdoor workers; to measure solar ultraviolet (UV) exposure in work environment; to describe the frequency of photoaging, precancerous lesions, and skin cancers in outdoor workers; to collect information on solar ultraviolet radiation exposure from incident cases of Non-Melanoma Skin Cancer (NMSC) recruited from Tuscany Cancer Registry. DESIGN: Outdoor workers completed a questionnaire devoted to collect information on sun protection attitudes during a typical summer working week. Environmental and personal measurements were carried out. Expert dermatologists examined outdoor workers to assess the frequency of photoaging, precancerous lesions, and skin cancer. A structured questionnaire was mailed to incident cases of NMSC. Information were collected on personal habits and working history, focusing on solar ultraviolet radiation exposure. SETTING AND PARTICIPANTS: Agriculture, construction, quarrying and fishing activities were considered: 292 employees responded to questions about the type of clothing used in the morning and in the afternoon,while working outdoors; 637 outdoor workers underwent skin examination. We contacted 743 cases of NMSC occurred in 2004; 498 subjects accepted to participate in this study. RESULTS: The clothing worn by surveyed subjects was often inadequate compared to the high level of exposure to UV. The skin examination of 637 outdoor workers highlighted 2 melanomas, 7 epitheliomas and 35 actinic keratoses. Among the 498 cases of NMSC, 135 (27%) were diagnosed in outdoor workers. Most represented economic activity sectors were: agriculture, construction, transport, sports. CONCLUSION: The characterization of outside workers revealed unsatisfactory sun protection behaviours. Moreover, previously undetected skin cancers were diagnosed. The study on MNSC confirms the complexity of studying the exposure to UV radiation. The Tuscany Regional project provided useful information on the risk of solar ultraviolet radiation in outdoor workers. Prevention programs are needed.

Skin photoaging in farmers occupationally exposed to ultraviolet radiation.

BACKGROUND: Most personal exposures to UV radiations occur from outdoor activities and several studies detected a significant association between skin cancer and outdoor occupation. OBJECTIVE: The aim of the study was to ascertain the prevalence of photoaging signs in a population of Italian farmers and in a population of indoor workers taking account of confounding factors. METHODS: 169 farmers and 198 indoor workers were classified for skin phototype and for skin photoaging, moreover 13 variables were taken into account. Marginal permutation tests were adopted for statistical analysis. RESULTS: Farmers were significantly older than the indoor workers. In workers occupationally exposed to UV photoaging increased with increasing age and years of occupational exposure to sunlight The distribution of skin phototype did not show significant differences in the two populations, while farmer showed a higher degree of photoaging than indoor workers. CONCLUSIONS: Even if farmers were older than the in door workers it seems that outdoor work produces a higher degree of photoaging.

GSH depletion, protein S-glutathionylation and mitochondrial transmembrane potential hyperpolarization are early events in initiation of cell death induced by a mixture of isothiazolinones in HL60 cells.

We recently described that brief exposure of HL60 cells to a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI) induces apoptosis at low concentrations (0.001-0.01%) and necrosis at higher concentrations (0.05-0.1%). In this study, we show that glutathione (GSH) depletion, reactive oxygen species generation, hyperpolarization of mitochondrial transmembrane potential (DeltaPsim) and formation of protein-GSH mixed disulphides (S-glutathionylation) are early molecular events that precede the induction of cell death by CMI/MI. When the cells exhibit common signs of apoptosis, they show activation of caspase-9, reduction of DeltaPsim and, more importantly, decreased protein S-glutathionylation. In contrast, necrosis is associated with severe mitochondrial damage and maximal protein S-glutathionylation. CMI/MI-induced cytotoxicity is also accompanied by decreased activity of GSH-related enzymes. Pre-incubation with L-buthionine-(S,R)-sulfoximine (BSO) clearly switches the mode of cell death from apoptosis to necrosis at 0.01% CMI/MI. Collectively, these results demonstrate that CMI/MI alters the redox status of HL60 cells, and the extent and kinetics of GSH depletion and S-glutathionylation appear to determine whether cells undergo apoptosis or necrosis. We hypothesize that S-glutathionylation of certain thiol groups accompanied by GSH depletion plays a critical role in the molecular mechanism of CMI/MI cytotoxicity.

Biochemical and biological aspects of protein thiolation in cells and plasma.

Protein thiolation is elicited by oxidation by different mechanisms and is involved in a variety of biological processes. Thiols, protein SH (PSH) and non-protein SH groups (NPSH, namely GSH), are in competition in all biological environments in the regulation of oxidant homeostasis because oxidants thiolate proteins, whereas GSH dethiolates them (e.g., GSSG + PSH --> GSSP + GSH). Although poorly investigated, the elimination of disulfides from thiolated proteins to regenerate critical PSH is important. These aspects are poorly known in cells, where glutaredoxin and peroxiredoxin operate as enzymes or potential chaperones to accelerate dethiolation. On the contrary, studies with plasma or albumin have highlighted the importance of protein conformation in dethiolation processes and have clarified the reason why homocysteine (thiol with potential toxicity) is preferentially bound to albumin as protein-thiol mixed disulfide with respect to other NPSH. Here we provide an overview of protein thiolation/dethiolation processes, with an emphasis on recent developments and future perspectives in this field.

Skin bank organization.

Skin allografts were first used at the end of the last century by Girdner [Girdner JH. Skin grafting with graft taken from the dead subject. Med Rec (NY) 1881;20:119-20]; however, routine storage of human tissue developed only in the 1930s to 1940s [Webster JP. Refrigerated skin grafts. Ann Surg 1944;120:431-49] when reliable preservation methods became available. The first proper skin bank was the US Navy Skin Bank, set up in 1949 [McCauley RL. The skin Bank. In: Herndon DN, editor. Total burn care. 1st ed. Philadelphia: Saunders; 1996. p. 159-63]. Several skin banks were subsequently established in the United States and Europe, and in most cases they were organized as multitissue banks. Nowadays, it is estimated that 30 to 50 tissue banks are active in the United States, working according to the American Association of Tissue Banking (AATB) standards (AATB. Standards for tissue banking; 1984) and federal regulations (Real E S and regulations. Fed Regist. 1993).

Other uses of homologous skin grafts and skin bank bioproducts.

The main use of homologous skin grafts or grafts of related bioproducts is in the treatment of severe burns. However, various new clinical and experimental sectors, in which this type of skin substitute can be useful, have recently emerged. The main new clinical indications for skin allografts include: skin loss, surgical wounds and bullous diseases. In these fields donor skin can be used for different purposes: as a physiological biological dressing to control pain and protect deep structures such as tendons, bones, cartilage and nerves, and to promote reepithelization with a significant reduction in healing time, and as skin substitute with dermal tissue to guide repair and make it as physiological as possible. In particular, skin bank bioproducts are currently used in the treatment of several conditions such venous and arterial leg ulcers, pressure ulcers, diabetic foot ulcers, pyoderma gangrenosum, post traumatic lesions, Mohs surgery, reconstructive surgery, wound cover in critical areas, aesthetic surgery, congenital epidermolysis bullosa and Lyell's syndrome. Skin bank bioproducts have also been used for experimental indications, to study in vitro toxicology and in vitro skin biology. Recently the demonstration that de-epidermized dermis (DED) has all the characteristics of an excellent dermal substitute into which various types of cells can be introduced and made to develop, opens exciting new possibilities of research in the field of wound healing and tissue engineering. Our preliminary observations seems to indicate that CD 34+ stem cells from umbilical cord blood can survive in DED and in a few weeks populate collagen bundles. The observation of tubular structures without lumina close to collagen bundles as well as clusters of epithelioid or fibroblast-shaped cells may represent aspects of differentiation of CD 34+ stem cells. More detailed and sophisticated studies are clearly needed to answer all the questions that these initial observations pose. Anyway the 3-dimensional model proposed seems to be suitable for the study of the behaviour of peripheral CD 34+ and perhaps also other types of stem cells in 3-dimensional dermal matrix.

Helicobacter pylori immunoproteomes in case reports of rosacea and chronic urticaria.

Rosacea and chronic urticaria are two common skin disorders existing in idiopathic forms. A role of Helicobacter pylori bacterium infection in the aetiopathogenesis of rosacea or chronic urticaria has been suggested although still controversial. The aim of the present study was to establish a relationship between H. pylori infection and rosacea chronic urticaria by means of an immunoproteomic investigation. We analyzed immunoglobulin A (IgA)-, IgG-, and IgE-mediated immune-responses against H. pylori antigens and we identified some bacterial immunoresponsive proteins. A general IgA- and IgE-mediated immune response against antioxidative bacterial proteins was observed. A correlation between the bacterial occurrence and skin diseases pathogenesis is discussed.

Skin allograft in the treatment of toxic epidermal necrolysis (TEN).

BACKGROUND: TEN is a severe form of exfoliative dermatitis. Its course is acute and its outcome fatal in 40% of cases. Wound cover to prevent fluid/protein loss and infections and to control pain, is the first step, as for burns. Skin allograft can be successfully used for this purpose. OBJECTIVE: We report two cases of TEN with de-epithelialization of 50 and 70% of the total body surface area. The patients were given support therapy and treated with human glycerol-preserved skin allografts for wound cover. METHODS: Patients were grafted with glycerol-preserved donor skin, obtained from a skin bank. RESULTS: Re-epithelization of treated areas was complete in 8 days; pain relief was obtained soon after the graft. CONCLUSIONS: Glycerol-preserved skin allograft is an effective treatment in extensive skin loss, for its barrier and analgesic effect. Quality standards of this product ensure safety and simplicity of use at limited cost.

The effects of age and hyperhomocysteinemia on the redox forms of plasma thiols.

We assayed the redox forms of cysteine (reduced [CSH], oxidized [CSSC], and bound to protein [CS-SP]), cysteinylglycine (CGSH; cysteinylgycine disulfide [CGSSGC] and cysteinylglycine-protein mixed disulfide [CGS-SP]), glutathione (GSH; glutathione disulfide [GSSG] and glutathione-protein mixed disulfide [GS-SP]), homocysteine (Hcy; homocystine [HcyS] and homocystine-protein mixed disulfides [bHcy]), and protein sulfhydryls in the plasma of healthy subjects (divided into 8 groups ranging in age from birth to 70 years) and patients with mild hyperhomocysteinemia associated with cardiovascular disease (heart-transplant patients) or vascular atherosclerosis, with or without renal failure. In healthy individuals, levels of disulfides and protein-mixed disulfides were more abundant than those of thiols, and those of protein-thiol mixed disulfides were higher than disulfides. Concentrations of CSH, GSH, and CGSH in the various groups had profiles characterized by a maximum over time. The concentration of Hcy was unchanged up to the age of 30 years, after which it increased. CSSC concentration increased gradually with age, whereas concentrations of the other disulfides were essentially unchanged. By contrast, the concentrations of all protein-thiol mixed disulfides, especially those with CSH, increased gradually with age. Ranks of distribution of the reduced forms changed with age (at birth, CSH > CGSH > GSH > Hcy; in 1- to 2-year-olds, CSH > GSH > CGSH > Hcy; and in 51- to 70-year-olds, CSH > CGSH = GSH > Hcy), whereas those of disulfides and protein-thiol mixed disulfides were substantially unchanged (in all age groups, CSSC > CGSSGC > GSSG = HcyS and CS-SP > CGS-SP > bHcy > GS-SP). In patients with pathologic conditions, plasma levels of disulfide forms CSSC, HcyS, CS-SP, and bHcy were significantly increased, whereas other redox forms of thiols were unchanged or showed variations opposite (increasing or decreasing) to control values. Maximal increases in disulfides and protein-thiol mixed disulfides were associated with renal failure. Our data suggest that increases in plasma bHcy concentrations in subjects with pathologic conditions were more likely the result of activation of thiol-disulfide exchange reactions between free reduced Hcy and CS-SP than of a direct action of reactive oxygen species.