[Show abstract][Hide abstract] ABSTRACT: The unfolded protein response (UPR) is a conserved cellular response designed to alleviate damage and promote survival of cells experiencing stress; however, prolonged UPR activation can result in apoptotic cell death. The UPR, activated by cytokine-induced nitric oxide (NO) production, has been proposed to mediate beta-cell death in response to cytokines. In this study, the role of UPR activation in cytokine-induced beta-cell death was examined.
The effects of cytokine treatment of rat and human islets and RINm5F cells on UPR activation, NO production, and cell viability were examined using molecular and biochemical methodologies.
UPR activation correlates with beta-cell death in interleukin (IL)-1-treated rat islets. NO mediates both cytokine-induced UPR activation and beta-cell death as NO synthase inhibitors attenuate each of these IL-1-stimulated events. Importantly, cytokines and tunicamycin, a classical UPR activator, induce beta-cell death by different mechanisms. Cell death in response to the classical UPR activator is associated with a 2.5-fold increase in caspase-3 activity, while IL-1 fails to stimulate caspase-3 activity. In addition, cell death is enhanced by approximately 35% in tunicamycin-treated cells expressing an S51A eIF2 alpha mutant that cannot be phosphorylated or in cells lacking PERK (protein kinase regulated by RNA/endoplasmic reticulum-like kinase). In contrast, neither the absence of PERK nor the expression of the S51A eIF2 alpha mutant affects the levels of cytokine-induced death.
While cytokine-induced beta-cell death temporally correlates with UPR activation, the lack of caspase activity and the ability of NO to attenuate caspase activity suggest that prolonged UPR activation does not mediate cytokine-induced beta-cell death.
[Show abstract][Hide abstract] ABSTRACT: Knowledge of experimental residence time distribution of foods containing particles being processed aseptically is crucial to designing safe thermal processes while simultaneously ensuring optimum product quality. Past attempts at designing high-temperature short-time process recommendations depended on conservative estimates for residence time in a holding tube while ignoring the effect of the scraped-surface heat exchangers. This resulted in excessive thermal treatment and a consequent loss of textural and nutritional quality attributes.Experiments were conducted to determine residence time of particles in food being processed in a commercial scale aseptic processing system at 135–140 °C. Residence time data, which included among others, the effect of particle-particle interaction in a viscous fluid product made up of a 6% starch solution containing 15% diced potatoes, were collected and treated statistically.The data show that the methodology developed yields reproducible data, which when treated statistically, allows prediction of fastest particle residence time with a high level of confidence. In addition, data presented for the high-viscosity starch-based product, showed a marked absence of any channeling effects as the product passed through scraped-surface heat exchangers, a holding tube, and interconnecting piping of a commercial processing system.
No preview · Article · May 1996 · Journal of Food Engineering
[Show abstract][Hide abstract] ABSTRACT: James Mac Hulbert and Leyland Pitt explain the demise of functional marketing in terms of more competitive markets, more powerful customers and more pervasive information technology. Post-functional marketing to create competitive advantage must be holistic - a philosophy that permeates the whole company. Transforming marketing in this way requires attention to 'supporting' elements in the organization such as structure, systems and human resource managements as well as strategic considerations including the more traditional statements of vision, values and mission. For the future, the authors stress the roles of leadership, changing in small steps, and being practical rather than intellectual. These will strengthen marketing as a capability rather than as a function.
No preview · Article · Jan 1996 · European Management Journal
[Show abstract][Hide abstract] ABSTRACT: The addition of various amounts of acetic acid to pureed cucumbers inoculated with Clostridium botulinum spores has shown that outgrowth is inhibited at pH 4.8 but not at pH 5.0. Inoculation experiments with whole cucumbers showed that as little as 0.9% acetic acid in the brine was sufficient to prevent outgrowth from spore inocula as high as 10(6)/cucumber. It was further shown that the rapid rate of acetic acid penetration into fresh-pack pickles prevents the growth of any C. botulinum spores that may be present.
Preview · Article · Aug 1976 · Applied and Environmental Microbiology