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Integrated pest management (IPM) is a method of reducing economic, human health, and environmental risks from pests and pest management strategies. There are questions about the long-term success of IPM programs in relation to continued use of pesticides in agriculture. Total pounds of pesticides applied is a mis-measure of the impact of IPM in agriculture. A more complete measurement of the long-term impact of IPM includes consideration of changes in agricultural production practices and productivity, toxicity of the pesticides used, risks from human exposure to pesticides, and environmental sampling for pesticides in air and water resources. In recent decades, agricultural IPM programs have evolved to address invasive pests, shifts in endemic pest pressures, reductions in pest damage tolerance in markets, and increases in crop yields. Additionally, pesticide use data from Arizona and California revealed reduced use of pesticides in some toxicity categories but increased use of pesticides in a couple of categories. Data from federal and California programs that monitored pesticide residue on food have documented low pesticide risk to consumers. Environmental monitoring programs documented decreased pesticide levels in surface water resources in agricultural watersheds in the western United States and low levels of pesticides in air resources in agricultural areas in California. The focus of IPM assessment should be on reducing economic, human health, and environmental risks, not on pounds of pesticides applied. More broadly, IPM programs have evolved to address changes in pests and agricultural production systems while continuing to reduce human health and environmental risk from pesticides.

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OBJECTIVE: To investigate the role of furin-like enzymes in the proteolytic cascades leading to cartilage breakdown and to examine which collagenase(s) contribute to collagen degradation. METHODS: Bovine nasal cartilage was stimulated to resorb with the addition of interleukin-1alpha (IL-1alpha)/oncostatin M (OSM) in the presence or absence of a furin inhibitor, Dec-RVKR-CH(2)Cl, or selective matrix metalloproteinase 1 (MMP-1) inhibitors. Collagen and proteoglycan levels were determined by assay of hydroxyproline and sulfated glycosaminoglycan, respectively. Collagenase and gelatinase activity were measured using (3)H-acetylated collagen and gelatin zymography, respectively. RESULTS: The addition of Dec-RVKR-CH(2)Cl to stimulated cartilage reduced the release of collagen fragments and the levels of active collagenase and MMP-2, suggesting that furin-like enzymes are involved in the cascades leading to activation of procollagenases. At MMP inhibitor concentrations that selectively inhibit MMP-1, no inhibition of collagen release was observed, but increasing the concentration to the 50% inhibition concentration for MMP-13 resulted in a 50% blockage of collagen release. The addition of Dec-RVKR-CH(2)Cl to resorbing cartilage also partially blocked proteoglycan release, thus demonstrating a role for furin-activated enzymes in the pathways leading to proteoglycan degradation. CONCLUSION: Furin-like enzymes are involved in cascades leading to activation of procollagenases and degradation of collagen. MMP-13, which can be activated by furin-processed membrane-type 1 MMP-1, appears to be a major collagenase involved in collagen degradation induced by IL-1alpha/OSM. Furin-like enzymes also appear to play a role in the pathways leading to proteoglycan degradation. These findings are of importance when considering proteinase inhibition as a target for therapeutic intervention in arthritic diseases.

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OBJECTIVE: Bovine and human cartilages in explant culture respond to proinflammatory cytokines with the up-regulation of procollagenases. In stimulated bovine nasal cartilage (BNC), >90% of collagen is released by day 14 of culture, but collagen release is rarely seen before day 7. The aim of this study was to investigate if activation of procollagenases is a rate-limiting step in cartilage collagen breakdown. METHODS: BNC and human articular cartilage explants were cultured with interleukin-1alpha (IL-1alpha) and/or oncostatin M (OSM) with or without test reagents. Collagen levels were determined by assay of hydroxyproline. Collagenase activity was measured using the diffuse fibril assay. RESULTS: The addition of procollagenase activators, matrix metalloproteinase 3 (MMP-3), and APMA to IL-1alpha/OSM-stimulated BNC resulted in early release of collagen. The release with APMA was completely blocked by the addition of tissue inhibitor of metalloproteinases 1. This shows that procollagenases are present early in the culture period, but cartilage collagen breakdown does not happen until activation occurs. The addition of plasminogen to IL-1alpha/OSM-stimulated cartilage produced early collagen release in bovine and a significant increase in human cartilage. Thus, plasminogen activators (PAs) are present and convert plasminogen to plasmin, a known activator of several MMPs, including collagenases. Addition of alpha1-proteinase inhibitor or a urokinase-type PA inhibitor, 7-amino-4-chloro-3-(3-isothiureidopropoxy) isocoumarin, partially blocked the breakdown of collagen from IL-1alpha/OSM-treated bovine cartilage. This suggests that serine proteinases are involved in the activation cascades of procollagenases that result in cartilage collagen breakdown. CONCLUSION: The activation of procollagenases is a key control point in cartilage collagen breakdown, and serine proteinase pathways activate MMPs.

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There is the need for a simple, effective procedure for separating alpha 2 macroglobulin-cytokine complexes from free cytokine in order that the nature and possible immunological significance of cytokine-binding by alpha 2 macroglobulin (alpha 2-M) might be further investigated. This presentation describes a method which exploits the presence of zinc-binding sites on alpha 2-M which permit the isolation of complexes from other proteins by zinc-affinity chromatography. Furthermore the method may be used in either a column or batch format.

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alpha 2 macroglobulin (alpha 2M), a 725 kDa plasma protein, has been reported to bind a range of cytokines. We have therefore investigated its effect on a number of commercial cytokine assays. The methylamine converted fast form of the molecule was found to reproducibly depress, by 26% or more, the standard curves obtained with certain commercial assays for IL-2 and for tumor necrosis factor alpha, and had a small inhibitory effect on some IL-4 assays. In contrast it slightly enhanced or had no effect on ELISAs for IL-1 beta and IL-6. The inhibition observed was directly proportional to the concentration of alpha 2 M used in the range 0.5-5 mg/ml. Studies in the IL-2 system also revealed that it was largely attributable to the fast form of alpha 2M. Preliminary evidence suggests that the effects observed may be dependent on the assay source. These findings may be relevant to the assay of biological fluids in which alpha 2 M is present.

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The effects of Mount St. Helens volcanic ash on rings of hamster tracheal epithelium in organ culture were studied. Volcanic ash samples with mass median aerodynamic diameters (MMAD) of 7.7 micrometers and 1.6 micrometers caused markedly different alterations in the tracheal mucosa. Examination by SEM of the ventral epithelial surface of tissue from untreated control explants after 2 weeks in culture showed equal numbers of ciliated and microvillous cells. Examination by SEM of tracheas exposed to the smaller size particles revealed that ash concentrations as low as 1 microgram/ml increased mucous secretion after one 2-hr exposure. After four or nine 2-hr exposures, cells contained cilia that were short and blunt. Ciliary activity after these exposures showed a significant depression in beating frequency. Tracheal ring cultures exposed to the larger volcanic ash particles exhibited moderate cytomorphological changes after one 2-hr exposure at concentrations of 1, 10 and 100 micrograms/ml. As the number of exposures increased, most of the columnar cell layer was lost, resulting in exposure of the basal cells. After nine exposures at the two highest concentrations of ash (10 and 100 micrograms/ml), only a few ciliated cells were remaining. Statistically significant reductions in ciliary activity paralleled the epithelial damage. The degree of epithelial damage and changes in the cilia beating frequency were related to the dose and the number of exposures to the volcanic ash.

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