Preparation of Polyethylene Composites Containing Silver(I) Acylpyrazolonato Additives and SAR Investigation of their Antibacterial Activity.

Novel composite materials PEn (n = 1-9) have been prepared by an easily up-scalable embedding procedure of three different families of Ag(I) acylpyrazolonato complexes in polyethylene (PE) matrix. In details, PE1-PE3 composites contain polynuclear [Ag(QR)]n complexes, PE4-PE6 contain mononuclear [Ag(QR)(L)m] complexes and PE7-PE9 are loaded with mononuclear [Ag(QR) (PPh3)2] complexes, respectively (where L = 1-methylimidazole or 2-ethylimidazole, m = 1 or 2, and HQR = 1-phenyl-3-methyl-4-RC(═O)-5-pyrazolone, where in detail HQfb, R = -CF2CF2CF3; HQcy, R = -cyclo-C6H11; HQbe, R = -C(H)═C(CH3)2). The PEn composites, prepared by using a 1:1000 w/w silver additive/polyethylene ratio, have been characterized in bulk by IR spectroscopy and TGA analyses, which confirmed that the properties of polyethylene matrix are essentially unchanged. AFM, SEM, and EDX surface techniques show that silver additives form agglomerates with dimensions 10-100 µm on the polyethylene surface, with a slight increment of surface roughness of pristine plastic within 50 nm. However, the elastic properties of the composites are essentially the same of PE. The antibacterial activity of all composites has been tested against three bacterial strains (E. coli, P. aeruginosa and S. aureus) and results show that two classes of composites, PE1-PE3 and PE4-PE6, display high and persistent bactericidal and bacteriostatic activity, comparable to PE embedded with AgNO3. By contrast, composites PE7-PE9 exhibit a reduced antibacterial action. Contact and release tests in several conditions for specific migration of Ag+ from plastics, indicate a very limited but time persistent release of silver ions from PE1-PE6 composites, thus suggesting that they are potential antibacterial materials for future applications. Instead, PE7-PE9 almost do not release silver, only trace levels of silver ions being detected, in accordance with their reduced antibacterial action. None of the composites is toxic against higher organisms, as confirmed by D. magna test of ecotoxicity.

Linkage Isomerism in Silver Acylpyrazolonato Complexes and Correlation with Their Antibacterial Activity.

Novel silver(I) acylpyrazolonato coordination polymers of formula [Ag(Q(R))]n (1-3) have been synthesized by interaction of silver nitrate with HQ(R) in methanol in the presence of an equivalent quantity of KOH (in general HQ(R) = 1-phenyl-3-methyl-4-RC(═O)-5-pyrazolone, in detail HQ(fb), R = -CF2CF2CF3; HQ(cy), R = -cyclo-C6H11; HQ(be), R = -C(H)═C(CH3)2). [Ag(Q(R))]n react with 2-ethylimidazole (2EtimH), 1-methylimidazole (Meim), and triphenylphosphine (PPh3), affording the mononuclear Ag(Q(fb))(EtimH) (4), Ag(Q(cy))(Meim)2 (5), Ag(Q(be))(Meim) (6), and Ag(Q(R))(PPh3)2 (7-9). All complexes have been analytically and spectroscopically characterized, and for some of them the X-ray crystal structure has been resolved. In particular, the single crystal molecular structure determination of Ag(Q(fb))(EtimH) and Ag(Q(be))(PPh3)2 has confirmed the different coordination modes of the HQ(fb) and HQ(be) acylpyrazolone ligands, the former being bound to the silver(I) ion in a monodentate fashion while the latter in the O2-chelating mode. Density functional theory computations suggest new insights about metal-ligand interactions and the observed linkage isomerism. While phosphine-containing complexes Ag(Q(R))(PPh3)2 (7-9) seem not to be able to efficiently inhibit the growth of Escherichia coli and Staphylococcus aureus, the polynuclear complexes [Ag(Q(R))]n (1-3) and the mononuclear Ag(Q(fb))(EtimH) (4), Ag(Q(cy))(Meim)2 (5), and Ag(Q(be))(Meim) (6) show a high and almost steady in time antibacterial activity, comparable to that of AgNO3. This activity is likely related to the degree of saturation of the silver center and to the presence of different ancillary ligands in the diverse typologies of complexes.

Malignant mesothelioma due to non-occupational asbestos exposure from the Italian national surveillance system (ReNaM): epidemiology and public health issues.

INTRODUCTION: Italy produced and imported a large amount of raw asbestos, up to the ban in 1992, with a peak in the period between 1976 and 1980 at about 160,000 tons/year. The National Register of Mesotheliomas (ReNaM, "Registro Nazionale dei Mesoteliomi" in Italian), a surveillance system of mesothelioma incidence, has been active since 2002, operating through a regional structure. METHODS: The Operating Regional Center (COR) actively researches cases and defines asbestos exposure on the basis of national guidelines. Diagnostic, demographic and exposure characteristics of non-occupationally exposed cases are analysed and described with respect to occupationally exposed cases. RESULTS: Standardised incidence rates for pleural mesothelioma in 2008 were 3.84 (per 100,000) for men and 1.45 for women, respectively. Among the 15,845 mesothelioma cases registered between 1993 and 2008, exposure to asbestos fibres was investigated for 12,065 individuals (76.1%), identifying 530 (4.4%) with familial exposure (they lived with an occupationally exposed cohabitant), 514 (4.3%) with environmental exposure to asbestos (they lived near sources of asbestos pollution and were never occupationally exposed) and 188 (1.6%) exposed through hobby-related or other leisure activities. Clusters of cases due to environmental exposure are mainly related to the presence of asbestos-cement industry plants (Casale Monferrato, Broni, Bari), to shipbuilding and repair activities (Monfalcone, Trieste, La Spezia, Genova) and soil contamination (Biancavilla in Sicily). CONCLUSIONS: Asbestos pollution outside the workplace contributes significantly to the burden of asbestos-related diseases, suggesting the need to prevent exposures and to discuss how to deal with compensation rights for malignant mesothelioma cases induced by non-occupational exposure to asbestos.

Epidemiological patterns of asbestos exposure and spatial clusters of incident cases of malignant mesothelioma from the Italian national registry.

BACKGROUND: Previous ecological spatial studies of malignant mesothelioma cases, mostly based on mortality data, lack reliable data on individual exposure to asbestos, thus failing to assess the contribution of different occupational and environmental sources in the determination of risk excess in specific areas. This study aims to identify territorial clusters of malignant mesothelioma through a Bayesian spatial analysis and to characterize them by the integrated use of asbestos exposure information retrieved from the Italian national mesothelioma registry (ReNaM). METHODS: In the period 1993 to 2008, 15,322 incident cases of all-site malignant mesothelioma were recorded and 11,852 occupational, residential and familial histories were obtained by individual interviews. Observed cases were assigned to the municipality of residence at the time of diagnosis and compared to those expected based on the age-specific rates of the respective geographical area. A spatial cluster analysis was performed for each area applying a Bayesian hierarchical model. Information about modalities and economic sectors of asbestos exposure was analyzed for each cluster. RESULTS: Thirty-two clusters of malignant mesothelioma were identified and characterized using the exposure data. Asbestos cement manufacturing industries and shipbuilding and repair facilities represented the main sources of asbestos exposure, but a major contribution to asbestos exposure was also provided by sectors with no direct use of asbestos, such as non-asbestos textile industries, metal engineering and construction. A high proportion of cases with environmental exposure was found in clusters where asbestos cement plants were located or a natural source of asbestos (or asbestos-like) fibers was identifiable. Differences in type and sources of exposure can also explain the varying percentage of cases occurring in women among clusters. CONCLUSIONS: Our study demonstrates shared exposure patterns in territorial clusters of malignant mesothelioma due to single or multiple industrial sources, with major implications for public health policies, health surveillance, compensation procedures and site remediation programs.

Novel composite plastics containing silver(I) acylpyrazolonato additives display potent antimicrobial activity by contact.

New silver(I) acylpyrazolonato derivatives displaying a mononuclear, polynuclear, or ionic nature, as a function of the ancillary azole ligands used in the synthesis, have been fully characterized by thermal analysis, solution NMR spectroscopy, solid-state IR and NMR spectroscopies, and X-ray diffraction techniques. These derivatives have been embedded in polyethylene (PE) matrix, and the antimicrobial activity of the composite materials has been tested against three bacterial strains (E. coli, P. aeruginosa, and S. aureus): Most of the composites show antimicrobial action comparable to PE embedded with AgNO3 . Tests by contact and release tests for specific migration of silver from PE composites clearly indicate that, at least in the case of the PE, for composites containing polynuclear silver(I) additives, the antimicrobial action is exerted by contact, without release of silver ions. Moreover, PE composites can be re-used several times, displaying the same antimicrobial activity. Membrane permeabilization studies and induced reactive oxygen species (ROS) generation tests confirm the disorganization of bacterial cell membranes. The cytotoxic effect, evaluated in CD34(+) cells by MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazoliumbromide) and CFU (colony forming units) assays, indicates that the PE composites do not induce cytotoxicity in human cells. Studies of ecotoxicity, based on the test of Daphnia magna, confirm tolerability of the PE composites by higher organisms and exclude the release of Ag(+) ions in sufficient amounts to affect water environment.

Recommendations for assessing water quality and safety on board merchant ships.

INTRODUCTION: Health and diseases on board ships may depend on water. Interventions to improve the quality of water may bring to significant benefits to health and water stores/supply and should be controlledto protect health. This paper has reviewed the main regulations for the control of water safety and qualityon board ships and presents some practical recommendations for keeping water healthy and safe in passenger and cargo merchant ships. METHODOLOGY: The main international regulations and guidelines on the topic were analysed. Guidelines forWater Quality on Board Merchant Ships Including Passenger Vessels of Health Protection Agency, World Health Organisation (WHO) Guide to Ship Sanitation, WHO Guidelines for Drinking Water Quality, WHO Water Safety Plan and the United States Center for Disease Control and Prevention Vessel Sanitation Program were examined. Recommendations for passenger and, if available, for cargo ships were collected and compared. Recommended questionnaire: A questionnaire summarising the main information to collect for assessingthe enough quality of water for the purposes it should be used on board is proposed. The need of havinga crew member with water assessment duties on board, trained for performing these activities properlyis discussed. CONCLUSIONS: Water quality on board ships should be monitored routinely. Monitoring should be directedto chemical and microbiological parameters for identifying possible contamination sources, using specifickits by a designed crew member. More detailed periodic assessments should be under the responsibility ofspecialised personnel/laboratories and should be based on sample collection from all tanks and sites of waterdistribution. It is important to select a properly trained crew member on board for monitoring water quality.

[An epidemic strain of Acinetobacter baumannii in two long-term care facilities]. / Evento epidemico da Acinetobacter baumannii in pazienti lungodegenti.

This study describes an epidemic strain of Acinetobacter baumannii (AB) in two long-term care facilities. Assessment was focused on the spreading modalities of AB infection, the risk of acquiring the infection from colonized patients, the multidrug-resistant features, the clinical characteristics of affected patients, and the average length of hospital stay prior to and after AB infection. The effects of AB spreading among the healthcare operators and the environment are also evaluated, along with a description of the clinical course and outcome, and the efficacy of implemented preventive measures. AB is an opportunistic pathogen with increasing relevance in a variety of nosocomial infections.

Neuropeptide expression and T-lymphocyte recruitment in facial nucleus after facial nerve axotomy.

Axonal injury in the peripheral nervous system can have a strong impact on the neurons and the surrounding non-neuronals cells. The aim of this study was to evaluate the immunohistochemistry signals of the vasoactive intestinal peptide (VIP), substance P (SP), and CD3+ T cells and the messenger RNA levels of neuropeptides in the facial nucleus (FN) at 7, 14, and 21 days after peripheral facial nerve axotomy. Moreover, the authors assayed the peripheral blood levels of interleukin (IL-1ß), tumor necrosis factor-α, and IL-6 serum levels at 24 and 48 hours after the surgical procedures. Immunohistochemistry analysis revealed that VIP and SP expression is strongly induced in FN after peripheral facial nerve axotomy at 7 days, the CD3+ pan-T cells peak at 14 days. Polymerase chain reaction analysis for VIP and SP messenger RNA levels confirms the immunohistochemical data, but VIP level remains significantly high for 14 days. The serum level of IL-6 48 hours after axotomy was significantly higher than after 24 hours; there were no significant changes for IL-1ß and tumor necrosis factor-α serum levels between 24 and 48 hours. Our data reveal that FN neurons are under neuropeptidergic influence and show that modulation/modification of VIP and SP expression in FN injury models facilitates the crossing of the blood-brain barrier. On the contrary, our results emphasize the role of the T cells in preventing initial neurodegeneration or neuronal death. The high serum levels of IL-6 at 1 to 2 days suggest that this cytokine could play a central role in the initiation of immunosurveillance and provide advance information on the recruitment of CD3+ T lymphocytes in the FN.

Antibacterial action of 4,4'-bipyrazolyl-based silver(I) coordination polymers embedded in PE disks.

Coupling the rigid spacer 4,4'-bipyrazole (H(2)BPZ), in its anionic or neutral form, to different silver(I) salts allowed isolation of the novel coordination polymers [Ag(2)(BPZ)] (1) and [Ag(H(2)BPZ)(X)] (X = NO(3), 2; ClO(4), 3; BF(4), 4; PF(6), 5; CH(3)SO(3), 6; CF(3)SO(3), 7), which were fully characterized by infrared and emission spectroscopies, thermal analysis, and X-ray powder diffraction. The crystal structure of 1 consists of 2-D layers containing 1-D chains of Ag(I) ions bridged by exo-tetradentate bipyrazolato moieties. The crystal structures of the [Ag(H(2)BPZ)(X)] species 2-7 feature 1-D chains of [Ag(H(2)BPZ)] stoichiometry, along which the metal centers are bridged by exo-bidentate bipyrazolyl spacers. Contacts among adjacent chains are mediated by the counterions through nonbonding interactions involving the Ag(I) ions and the pyrazolyl N-H groups. Thermogravimetric analyses disclosed the good thermal stability of these materials, decomposing in the range 200-300 °C. Under UV irradiation at room temperature, all the species showed a yellow-green emission centered in the range 520-522 nm. When embedded into polyethylene disks, 1, 2, and 4-7 demonstrated their activity as topical antibacterial agents against suspensions of E. coli, P. aeruginosa, and S. aureus: complete reduction of the three bacterial strains was achieved in 24 h, reduction of S. aureus reaching ca. 90% in only 2 h. Biocidal action was expressed also by contact susceptibility tests.

Diaphragmatic breathing reduces postprandial oxidative stress.

OBJECTIVES: A number of studies suggest that postprandial hyperglycemia produces oxidative stress, leading to complications associated with diabetes. However, hyperglycemia-induced oxidative stress may affect groups of people other than diabetics, such as smokers and athletes with specific diet plans. Based on previous reports that seated breathing meditation reduces hyperglycemia, the present study was designed to determine the effects of diaphragmatic breathing on postprandial plasma glycemia, insulin, oxidative stress, and antioxidant levels in athletes with normal glucose metabolism. DESIGN: Data collected before and after consumption of a 900-calorie breakfast composed of 80% carbohydrates, 10% proteins, and 10% lipids were analyzed. Ten (10) minutes after the meal, 8 subjects spent 40 minutes performing diaphragmatic breathing in a quiet place. The other 8 subjects, representing the control group, spent the same time sitting in an equivalent quiet place reading a magazine. SUBJECTS: Data from 16 amateur male cyclists age 30.12±4.9 years (±SD) were analyzed. Their mean height and weight were 177.81±5.3 cm and 71.40±5.2 kg, respectively. All subjects underwent a physical examination and were determined to be in good health. OUTCOME MEASURES: Blood samples were collected immediately before the meal as well as 1 hour and 2 hours after the meal, and plasma levels of glucose, insulin, reactive oxygen metabolites, and biologic antioxidant potential were determined. Heart rate was also recorded. RESULTS: Results show that in normal subjects, acute hyperglycemia induces free-radical production while reducing the antioxidant levels (p<0.05). Diaphragmatic breathing reduces heart rates (p<0.01), increases insulin (p<0.05), reduces glycemia (p<0.01), and reduces free-radical production as indicated by the higher antioxidants levels (p<0.05). CONCLUSIONS: Diaphragmatic breathing, likely through the activation of the parasympathetic nervous system, increases insulin, reduces glycemia, and reduces reactive oxygen species production.

Effect of a probiotic intake on oxidant and antioxidant parameters in plasma of athletes during intense exercise training.

The aim of this study was to evaluate the effect of Lactobacillus rhamnosus IMC 501 and Lactobacillus paracasei IMC 502 on oxidative stress in athletes during a four-week period of intense physical activity. Two groups of twelve subjects each were selected for this analysis. The first group consumed a daily dose of a mixture of the two probiotic strains (1:1 L. rhamnosus IMC 501 and L. paracasei IMC 502; ~10(9) cells/day) for 4 weeks. The second group (control) did not consume any supplements during the 4 weeks. Blood samples collected immediately before and after the supplementation were analyzed, and plasma levels of reactive oxygen metabolites and biological antioxidant potential were determined. Faeces were also collected and analyzed before and at the end of the probiotic supplementation. Antioxidative activity and oxidative stress resistance of the two strains were determined in vitro. Results demonstrated that intense physical activity induced oxidative stress and that probiotic supplementation increased plasma antioxidant levels, thus neutralizing reactive oxygen species. The two strains, L. rhamnosus IMC 501(®) and L. paracasei IMC 502(®), exert strong antioxidant activity. Athletes and all those exposed to oxidative stress may benefit from the ability of these probiotics to increase antioxidant levels and neutralize the effects of reactive oxygen species.

Diaphragmatic breathing reduces exercise-induced oxidative stress.

Diaphragmatic breathing is relaxing and therapeutic, reduces stress, and is a fundamental procedure of Pranayama Yoga, Zen, transcendental meditation and other meditation practices. Analysis of oxidative stress levels in people who meditate indicated that meditation correlates with lower oxidative stress levels, lower cortisol levels and higher melatonin levels. It is known that cortisol inhibits enzymes responsible for the antioxidant activity of cells and that melatonin is a strong antioxidant; therefore, in this study, we investigated the effects of diaphragmatic breathing on exercise-induced oxidative stress and the putative role of cortisol and melatonin hormones in this stress pathway. We monitored 16 athletes during an exhaustive training session. After the exercise, athletes were divided in two equivalent groups of eight subjects. Subjects of the studied group spent 1 h relaxing performing diaphragmatic breathing and concentrating on their breath in a quiet place. The other eight subjects, representing the control group, spent the same time sitting in an equivalent quite place. Results demonstrate that relaxation induced by diaphragmatic breathing increases the antioxidant defense status in athletes after exhaustive exercise. These effects correlate with the concomitant decrease in cortisol and the increase in melatonin. The consequence is a lower level of oxidative stress, which suggests that an appropriate diaphragmatic breathing could protect athletes from long-term adverse effects of free radicals.

Immunological pattern alteration in shoe, hide, and leather industry workers exposed to hexavalent chromium.

OBJECTIVE: The aim of this work was to assess the effects of hexavalent chromium [Cr(VI)] on shoe, leather, and hide industry workers, based on the assumption that Cr(VI) can behave as an environmental immunological "stressor." METHODS: The immunological patterns of 84 male subjects were studied in relation to Cr(VI) hematic and urinary levels. Cr(VI) was measured through atomic absorption. Lymphocyte subsets, mitogen-mediated lymphocyte-proliferation, cytokine levels, and natural killer (NK) cytotoxic activity were also assayed. RESULTS: The urinary levels of the total amount of Cr(VI) were significantly higher in a subgroup of exposed subjects (group B) than in the control or in the lower exposed (group A). In group B, Cr(VI) caused a decrease in the density of glucocorticoid receptors (GR) on peripheral blood mononuclear cells (PBMC) and a increase of IL-6. Cr(VI) did not modify NK-mediated cytotoxicity, the plasmatic levels of inflammatory cytokines and related soluble receptors, and prostaglandin levels, while it tended to increase lymphocyte sensitivity to mitogens and the production of immunomodulant cytokines (IFN-gamma, IL-4, and IL-2). The experimental addition of Cr(VI) to the in vitro lymphocyte culture determined a significant inhibition of phagocytosis percentage, index, and killing percentage. These effects were neutralized by exogenous IFN-gamma. CONCLUSION: Cr(VI) could represent an environmental immunological stressor whose effects can be evaluated through laboratory surveys. The lymphocyte mitogen-induced proliferation, GR receptor on PBMC, and IL-6 plasma levels may represent a discriminating element between Cr(VI)-induced stress and other kinds of stress.

Individual susceptibility to hexavalent chromium of workers of shoe, hide, and leather industries. Immunological pattern of HLA-B8, DR3-positive subjects.

BACKGROUND: This study was designed to examine the effects of hexavalent chromium [Cr(VI)] on the immunological pattern of shoe, hide, and leather industry workers, moving from the hypothesis that some haplotypes (HLA-B8,DR3) can be important hidden risk cofactors. METHODS: Workplaces of 20 firms were monitored for total and respirable dusts and for total and hexavalent chromium. Cr(VI) on materials was also measured. Assay of chromium levels in blood and urine of 44 serological human leukocytes antigen (HLA)-typed workers (20 exposed, 15 HLA-B8,DR3-negative/5-positive and 24 non-exposed, 18 HLA-B8,DR3-negative/6-positive subjects) was performed by atomic absorption, and lymphocyte subsets (FACS-analysis), mitogen-mediate lympho-proliferation ([3H]thymidine incorporation), cytokine levels (ELISA), natural killer (NK) cytotoxic activity (51Cr-release assay) were determined. RESULTS: The environmental parameter levels are lower than threshold limit value-time-weighted average (TLV-TWA); in the materials, the Cr(VI) values exceeded the levels allowed. The peripheral blood mononuclear cells (PBMC) proliferation and the T-helper1 (TH1) cytokine pattern of subjects chronically exposed were significantly raised; addition in vitro of Cr(VI) further stimulated these parameters and in general the entire TH1 system and NK activity. The TH2 system was unaltered. In the HLA-B8,DR3-positive workers, immunologically "low responders", the addition of Cr(VI) in vitro caused a further reduction of the considered parameters in the exposed subjects with a dramatic deficit of the TH1 system. CONCLUSIONS: Results indicate the unsuitability of TLV-TWA as a line of demarcation between safe and dangerous Cr(VI) concentrations and the importance of individual genetic susceptibility for occupational and preventative medicine. In particular, the presence of the HLA-B8,DR3 alleles can represent an important cofactor of immunotoxic susceptibility consequent to chronic low-dose Cr(VI) exposure.