Coccidiosis and necrotic enteritis (NE) are globally common, sometimes intercurrent, diseases of poultry. The risk of NE, due to the Gram-positive bacterium Clostridium perfringens, has increased in recent years because of the voluntary or legally required withdrawal of the use of certain in-feed antibiotic growth promoters with anticlostridial activity. In-feed ionophorous anticoccidial drugs incidentally also possess anticlostridial activity. Such ionophores, although not banned, are usually precluded when live anticoccidial vaccines are used, potentially increasing yet further the risk of NE. This review provides information for the design of rational, integrated management strategies for the prevention and control of coccidiosis and NE in chickens by maintaining gut integrity. Because of differences in local availability of feed ingredients and national legislations regarding antibiotic growth promoters and anticoccidial vaccine licensing, no universal strategy is applicable. The diseases and their interactions are described under the headings of forms of disease, diagnosis, sources of infection, pathophysiological effects, predisposing factors, and control methods. Elements of gut integrity, which influences host predisposition and clinical responses to disease, include physical development, immune competence, gut enzyme activity, mucin production, gut flora and epithelial damage. Experimental studies of coccidiosis and NE are compared, and where possible reconciled, with field observations. Gaps in knowledge and necessary further experiments are identified. Insights are provided regarding interactions between coccidiosis, NE, and the use of live anticoccidial vaccines. Recent changes in NE prevalence in commercial flocks, and their possible causes, are discussed. The necessarily wide range of topics reviewed emphasizes the enormous complexity of this disease combination, and indicates the importance of a multidisciplinary approach in order to reduce its harmful impact on the world's poultry industry.
The use of live vaccines, either attenuated or non-attenuated, for the control of coccidiosis due to Eimeria infections in broiler breeder or layer chickens is well established. Use in broilers, however, has been slow to gain acceptance. This has been partly for economic reasons, but also because of perceived adverse effects on early chick growth, particularly with non-attenuated vaccines, and concerns about timely onset of protective immunity in such short-lived birds. This review describes advances in understanding of epidemiological factors and recent improvements of administration methods that have helped to allay these fears and to make the use of anticoccidial vaccines in broilers technically achievable. Topics discussed include: (1) types of commercially available vaccine, (2) vaccines in development, (3) vaccination methods and equipment, (4) basis of vaccine efficacy and immunogenic variation of parasites, (5) key factors in the survival, sporulation and dissemination of vaccinal oocysts, (6) descriptions and significance of patterns of litter oocyst accumulation and occurrence of intestinal lesions in vaccinated flocks, (7) rotation of anticoccidial vaccination and chemotherapy to restore drug sensitivity to resistant wild-type coccidia, (8) combinations of anticoccidial vaccination and chemotherapy, (9) interactions between coccidiosis and clostridiosis in broilers and compatibilities of potential control methods, (10) published performance data for live anticoccidial vaccines in broilers, (11) possible further developments of live vaccines.
Hostility, as measured by the Cook-Medley Hostility Scale of the Minnesota Multiphasic Personality Inventory, has been found to predict higher rates of both coronary heart disease and all-cause mortality. To evaluate one mechanism whereby hostility might contribute to health problems, the authors used regression models to determine whether hostility measured in college (1964-1966) predicted coronary risk factors assessed 21-23 years later (1987-1990) in 4,710 men and women. Of this group, 828 had lipids measured (1988-1991). Persons with higher hostility scores in college were significantly more likely at follow-up to consume more caffeine (r = 0.043), to have a larger body mass index (r = 0.055), to have higher lipid ratios (r = 0.092), and to be current smokers (r = 0.069) than those with lower hostility scores during college. Cross-sectional analyses found significant associations of contemporaneous hostility scores with the same four risk factors, as well as with alcohol consumption and hypertension (rs ranging from 0.043 to 0.117). These associations are large enough to have possible public health significance. We conclude that hostility may contribute to health problems through its influences on several coronary risk factors across the adult life span.
That document provided a basis for the Federal government to assess how to make strategic research and development (R&D) investments in this emerging field of nanotechnology through the formulation of national R&D priorities and a strategy for state, local, and Federal government support.This IWGN Workshop Report, Nanotechnology Research Directions, builds upon the foundation provided in the first report and incorporates a vision for how the nanotechnology community -Federal agencies, industries, universities, and professional societies --can more effectively coordinate efforts to develop a wide range of revolutionary commercial applications. It incorporates perspectives developed at a January 1999 IWGN-sponsored workshop by experts from universities, industry, and the Federal government. This report identifies challenges and opportunities in the nanotechnology field and outlines the necessary steps on how advances made in nano-science, engineering, and technology can help to boost our nation's economy, ensure better healthcare, and enhance national security in the coming decade.Preparing for the challenges of the new millennium requires strategic investments. Nanotechnology Research Directions will help our nation develop a balanced R&D nanotechnology infrastructure, advance critical research areas, and nurture the scientific and technical workforce of the next century. Nanotechnology Research Directions: IWGN Workshop ReportVision for Nanotechnology Ri&D in the Next Decade EXECUTIVE SUMMARYNanotechnology is the creation and utilization of materials, devices, and systems through the control of matter on the nanometer-length scale, that is, at the level of atoms, molecules, and supramolecular structures. The essence of nanotechnology is the ability to work at these levels to generate larger structures with fundamentally new molecular organization. These "nanostructures," made with building blocks understood from first principles, are the smallest human-made objects, and they exhibit novel physical, chemical, and biological properties and phenomena. The aim of nanotechnology is to learn to exploit these properties and efficiently manufacture and employ the structures.Control of matter on the nanoscale already plays an important role in scientific disciplines as diverse as physics, chemistry, materials science, biology, medicine, engineering, and computer simulation. For example, it has been shown that carbon nanotubes are ten times as strong as steel with one sixth of the weight, and that nanoparticles can target and kill cancer cells. Nanoscale systems have the potential to make supersonic transport costeffective and to increase computer efficiency by millions of times. As understanding develops of the way natural and living systems are governed by molecular behavior at nanometer scale, and as this understanding begins to be felt in science and medicine, researchers seek systematic approaches for nanoscale-based manufacturing of humanmade products.All natural materials and systems .establish their foundation a...
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