Homeostatic Proliferation Fails to Efficiently Reactivate HIV-1 Latently Infected Central Memory CD4+ T Cells

Homeostatic proliferation ensures the longevity of central memory T-cells by inducing cell proliferation in the absence of cellular differentiation or activation. This process is governed mainly by IL-7. Central memory T-cells can also be stimulated via engagement of the T-cell receptor, leading to cell proliferation but also activation and differentiation. Using an in vitro model of HIV-1 latency, we have examined in detail the effects of homeostatic proliferation on latently infected central memory T cells. We have also used antigenic stimulation via anti-CD3/anti-CD28 antibodies and established a comparison with a homeostatic proliferation stimulus, to evaluate potential differences in how either treatment affects the dynamics of latent virus populations. First, we show that homeostatic proliferation, as induced by a combination of IL-2 plus IL-7, leads to partial reactivation of latent HIV-1 but is unable to reduce the size of the reservoir in vitro. Second, latently infected cells are able to homeostatically proliferate in the absence of viral reactivation or cell differentiation. These results indicate that IL-2 plus IL-7 may induce a detrimental effect by favoring the maintenance of the latent HIV-1 reservoir. On the other hand, antigenic stimulation efficiently reactivated latent HIV-1 in cultured central memory cells and led to depletion of the latently infected cells via virus-induced cell death

Most bowel cancer symptoms do not indicate colorectal cancer and polyps: a systematic review

<p>Abstract</p> <p>Background</p> <p>Bowel symptoms are often considered an indication to perform colonoscopy to identify or rule out colorectal cancer or precancerous polyps. Investigation of bowel symptoms for this purpose is recommended by numerous clinical guidelines. However, the evidence for this practice is unclear. The objective of this study is to systematically review the evidence about the association between bowel symptoms and colorectal cancer or polyps.</p> <p>Methods</p> <p>We searched the literature extensively up to December 2008, using MEDLINE and EMBASE and following references. For inclusion in the review, papers from cross sectional, case control and cohort studies had to provide a 2×2 table of symptoms by diagnosis (colorectal cancer or polyps) or sufficient data from which that table could be constructed. The search procedure, quality appraisal, and data extraction was done twice, with disagreements resolved with another reviewer. Summary ROC analysis was used to assess the diagnostic performance of symptoms to detect colorectal cancer and polyps.</p> <p>Results</p> <p>Colorectal cancer was associated with rectal bleeding (AUC 0.66; LR+ 1.9; LR- 0.7) and weight loss (AUC 0.67, LR+ 2.5, LR- 0.9). Neither of these symptoms was associated with the presence of polyps. There was no significant association of colorectal cancer or polyps with change in bowel habit, constipation, diarrhoea or abdominal pain. Neither the clinical setting (primary or specialist care) nor study type was associated with accuracy.</p> <p>Most studies had methodological flaws. There was no consistency in the way symptoms were elicited or interpreted in the studies.</p> <p>Conclusions</p> <p>Current evidence suggests that the common practice of performing colonoscopies to identify cancers in people with bowel symptoms is warranted only for rectal bleeding and the general symptom of weight loss. Bodies preparing guidelines for clinicians and consumers to improve early detection of colorectal cancer need to take into account the limited value of symptoms.</p

The Potential for Heat Recovery from Beef Rendering Operations

Excerpt from the report: This publication reports on a heat recovery subsystem installed in 1976 as part of a total rendering system at a major midwestern meat packing firm. Included is a description of the total system and an economic evaluation of the heat recovery subsystem, including costs and potential savings. While this report describes a specific rendering system, indications are that similar results can be achieved in similar rendering system

Energy Costs for Marketing Fresh Beef

Excerpts from the report: This publication reports on a study of five systems and their associated energy costs for marketing fresh beef from packer to retail display case. In addition to a breakdown of costs by system, tables show costs by category (packer, central distributor or processor, transportation, retail store) and by energy source (electricity, natural gas, diesel fuel). The amounts of energy used are shown in the same detail as costs. Energy is expressed as Btu's 2 per 100 pounds of salable retail beef cuts. Results were based on theoretical engineering analyses and numerous calculations involving data collected in the field, as well as several stated assumptions. Taken into account was energy used to run the equipment directly related to preparing, packaging, handling, and refrigerating the beef, and transporting it through the systems

A Survey of Damage to Dry Groceries in Warehouses

Report Summary: Mishandling and packaging deficiencies were the major causes of damage to dry groceries in a 1985 survey of warehousing operations by the Agricultural Marketing Service, U.S. Department of Agriculture. The 10 warehouses surveyed employed a variety of systems from conventional to fully automated. Recouping practices varied from almost nonexistent to extensive salvaging and repacking. Disposition of recouped merchandise ranged from selling at full price to donating the item to charity. Damage reduction efforts varied similarly from none to regularly scheduled employee meetings and incentive programs. Few firms are fully aware of actual costs of damage, i.e., the many indirect costs over and above the value of the product lost. Many means are available to reduce damage; not all of them are economically feasible or applicable for any given firm. Suppliers must be willing to cooperate with their customers in resolving obvious packaging problems

Evaluation of a Shell Egg-Packing Plant Layout

Increasing costs of constructing and operating shell egg-packing plants make it essential that new or remodeled facilities be carefully planned to achieve maximum efficiency. This study evaluates the layout of a new shell egg-packing plant that demonstrates U.S. Department of Agriculture (USDA) planning concepts. The layout provides for adequate operating space and allows for future expansion at minimal cost. It also provides for the flow of products without backtracking, ease of maintaining sanitation, employee safety and welfare, maintenance of product quality, effective materials handling, and operating efficiency. Labor productivity in the new plant is 8.30 cases per worker-hour compared with 7.03 in the old plant, a gain of 18 percent