It is estimated that more than 1 million workers worldwide perform some type of welding as part of their work duties. Epidemiology studies have shown that a large number of welders experience some type of respiratory illness. Respiratory effects seen in full-time welders have included bronchitis, siderosis, asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders. Inhalation exposure to welding fumes may vary due to differences in the materials used and methods employed. The chemical properties of welding fumes can be quite complex. Most welding materials are alloy mixtures of metals characterized by different steels that may contain iron, manganese, chromium, and nickel. Animal studies have indicated that the presence and combination of different metal constituents is an important determinant in the potential pneumotoxic responses associated with welding fumes. Animal models have demonstrated that stainless steel (SS) welding fumes, which contain significant levels of nickel and chromium, induce more lung injury and inflammation, and are retained in the lungs longer than mild steel (MS) welding fumes, which contain mostly iron. In addition, SS fumes generated from welding processes using fluxes to protect the resulting weld contain elevated levels of soluble metals, which may affect respiratory health. Recent animal studies have indicated that the lung injury and inflammation induced by SS welding fumes that contain water-soluble metals are dependent on both the soluble and insoluble fractions of the fume. This article reviews the role that metals play in the pulmonary effects associated with welding fume exposure in workers and laboratory animals.

Immunogenic peptides are displayed in the context of class II histocompatibility proteins on the surface of antigen-presenting cells. Class H a and 13 subunits bind the invariant chain (I-chain), a transmembrane glycoprotein which must dissocite prior to peptide presentation. Proteolytic release of I-chain in an acidic compartment is followed by class II afi surface expression. Two distinct proteinases sequentially catalyze I-chain dissociation in B-lymphoblastoid cell lines. An aspartic proteinase initiates processing whereas a cysteine proteinase catalyzes the rmal stages of I-chain release. Inactivation of these enzymes prevents class II a1 maturation, demonstrating that acidic proteinases are essential for the generation of functional class II complexes. MATERIALS AND METHODSCells and Proteinase Inhibitors. The B-LCL Sweig (DR5) was cultured in Iscove's modification ofDulbecco's modified Eagle's medium plus 5% calf serum. Leupeptin (stock solution, 25 mg/ml in water) was used at a finial concentration of 5-50 jmg/ml. The aspartic proteinase inhibitors PD136517, PD136809, and PD134678 inactivate cathepsins D and E (8, 9). These inhibitors (50 mM stock solutions in dimethyl sulfoxide) were used at 25-50 ,uM, concentrations which reduced intracellular aspartic proteinase activity >75% after 24 hr.Antibodies. The antibody DA6.147 recognizes class II DR a chain, and L243 recognizes an epitope on mature DR5(wll) af3 (2, 10, 11). I-chain was detected with PIN1.1, an antibody specific for residues 12-28 (10).Immunoblotting and Metabolic Radiolabeling. Samples were normalized for protein and cell number before electrophoretic analysis and immunoblotting (10, 12). Class II a3 dimers were detected on immunoblots by using antibody L243 and sample buffer with 0.2% SDS (13). For metabolic radiolabeling, cells were pretreated with proteinase inhibitors for 1-2 hr, incubated with [35S]methionine for 30 min, and cultured in complete medium with or without inhibitors for 3.5 hr or 8 hr. In some experiments cells were radiolabeled for 4 hr. Cell lysates were immunoprecipitated for SDS/PAGE, and autoradiographs were quantitated by densitometry with the integrated area expressed in total intensity units. Resolution of glycosylated I-chain (Ip) from DR a was difficult on SDS/polyacrylamide gels. To calculate the accumulation of intact I-chain (It = I + Ip) with class II antigens, the formula (It + a)/, was used, assuming a constant a/l3 ratio. Subcellular Fractionation. Sweig cells (3 x 108) cultured with or without proteinase inhibitors were lysed in 0.5 mM CaCl2/1 mM NaHCO3/0.25 M sucrose/0.2 mM phenylmethanesulfonyl fluoride/0. 1 mM 7-amino-1-chloro-3-tosylamido-2-heptanone ("tosyllysine chloromethyl ketone") at pH 7.2 in a glass tissue homogenizer at 40C. The cell lysate was centrifuged at 900 x g for 10 min to pellet nuclei, and the supernatant was layered above 100 bil of 1.58 M sucrose and spun at 2000 x g for 15 min to remove mitochondria. The resulting supernatant was layered above continuous sucrose gradients (...

Biofouling on international vessels is an important mechanism for the inadvertent transfer of non-indigenous marine species around the globe. This paper describes the nature and extent of biofouling on 30 merchant vessels (ranging from 1400 to 32 000 gross registered tonnes) based on analysis of hull inspection video footage collected by two New Zealand commercial diving companies. A new method for measuring biofouling communities is applied, which aims to incorporate the potential for various hull locations to house non-indigenous marine species. Our analysis revealed that out-of-service vessels and vessels plying trans-Tasman routes possessed greater levels of biofouling than more active vessels. Dry-docking support strips and sea-chest gratings generally had the highest levels of biofouling and may pose relatively high biosecurity risks. Any future biosecurity surveillance should target these hull locations for non-indigenous species.

Nickel (Ni) metal and Ni compounds are widely used in applications like stainless steel, alloys, and batteries. Nickel is a naturally occurring element in water, soil, air, and living organisms, and is essential to microorganisms and plants. Thus, human and environmental nickel exposures are ubiquitous. Production and use of nickel and its compounds can, however, result in additional exposures to humans and the environment. Notable human health toxicity effects identified from human and/or animal studies include respiratory cancer, non-cancer toxicity effects following inhalation, dermatitis, and reproductive effects. These effects have thresholds, with indirect genotoxic and epigenetic events underlying the threshold mode of action for nickel carcinogenicity. Differences in human toxicity potencies/potentials of different nickel chemical forms are correlated with the bioavailability of the Ni2+ ion at target sites. Likewise, Ni2+ has been demonstrated to be the toxic chemical species in the environment, and models have been developed that account for the influence of abiotic factors on the bioavailability and toxicity of Ni2+ in different habitats. Emerging issues regarding the toxicity of nickel nanoforms and metal mixtures are briefly discussed. This review is unique in its covering of both human and environmental nickel toxicity data.

Copula, Concordance, Measures of association, Multivariate measures of association,