Biomedical subjects

J C Swanson

Publications and source records attributed to J C Swanson.

14 recordsLinked to original sources

PubMed2003

Value-added animal agriculture: inclusion of race and gender in the professional formula.

The Morrill Act establishing the land grant university system created public higher education institutions and paved the way for women and racial minorities to access them. Today women are -50% of the undergraduate population in animal science (AS) departments at the original land grant state universities, but racial minorities lag far behind, in part because the schools created under the 1890 legislation provided a diversion away from the state universities. Demographic trends from the U.S. Census and the Bureau of Labor Statistics indicate increasing positive growth in nonwhite workforce participation, with concurrent decreases in non-Hispanic male participation; men and women will be nearly equally represented by early in the 21st Century. In the faculties of AS departments, both women and minorities are seriously under-represented; causative factors underlying this phenomenon are similar. Although, historically, adherence to role stereotypes and divisions of labor explain some of the under-representation, these assumptions do not hold across all economic classes. Other factors contributing to the scarcity of women and faculty of color in AS include assumptions and mechanisms of scientific research itself; the very neutrality and disinterestedness of researchers, inherent in the scientific method, prevent recognition that values and personal biases affect decisions of hiring selections and mentoring effectiveness. We explore the cultural factors that underlie these values and biases that are common not only to agriculture but also to science more broadly.

Agriculture↗

PubMed1999

What are animal science departments doing to address contemporary issues?

Animal science departments are principle progenitors and disseminators of scientific information relating to the production of agricultural animals and their food products. The Land-Grant university missions of teaching, research, and extension are conduits designed to advance and enhance scientific knowledge within agriculture and to make this knowledge available to the public. I conducted an electronic survey to determine whether animal science departments are addressing contemporary issues through the traditional missions of the Land-Grant university system, which issues they are addressing, and how they are addressing these issues. Sixty-three animal science department administrative heads (AH) were contacted through an E-mail listserve maintained through Michigan State University. An introductory letter described the goals of the survey and asked the AH to submit contact information for faculty coordinators of teaching, research, and extension within their departments. Forty-nine percent of the administrative heads responded and submitted contact information for 72 faculty members. Survey questions were sent to the identified faculty. The total survey return was 38.9%, 37.7% of the respondents answered questions for teaching, 31.1% for research, and 31.1% for extension. Animal waste, animal welfare, and food safety are examples of issues where all three missions have concentrated efforts. However, graduate student education on issues was identified as lacking emphasis. Animal science departments are responding to contemporary issues in all three of the Land-Grant mission components.

Animal Husbandry↗

PubMed1995

Farm animal well-being and intensive production systems.

Animal welfare, or well-being, is a social issue with ethical, scientific, political, and aesthetic properties. Answering questions about the welfare of animals requires scientific definition, assessment, solutions, and public acceptance. With respect to the actual well-being of the animal, most issues are centered on how the animal "feels" when managed within a specific level of confinement, during special agricultural practices (e.g., tail docking, beak trimming, etc.) and handling. Questions of this nature may require exploration of animal cognition, motivation, perception, and emotional states in addition to more commonly recognized indicators of well-being. Several general approaches have emerged for solving problems concerning animal well-being in intensive production systems: environmental, genetic, and therapeutic. Environmental approaches involve modifying existing systems to accommodate specific welfare concerns or development of alternative systems. Genetic approaches involve changing the behavioral and (or) physiological nature of the animal to reduce or eliminate behaviors that are undesirable within intensive system. Therapeutic approaches of a physical (tail docking, beak trimming) and physiological (drug and nutritional therapy) nature bring both concern and promise with regard to the reduction of confinement stress. Finally, the recent focus on commodity quality assurance programs may indirectly provide benefits for animal well-being. Although research in the area of animal well-being will provide important information for better animal management, handling, care, and the physical design of intensive production systems there is still some uncertainty regarding public acceptance. The aesthetics of modern intensive production systems may have as much to do with public acceptance as with science.

Animal Husbandry↗

PubMed1994

Review: welfare perspectives on hens kept for egg production.

The wild ancestors of chickens, along with those of most other farm animals, were preadapted to domestication because their lack of specialized requirements allowed them to adapt to a wide variety of environments provided by humans. Currently most commercial chickens kept for table-egg production are incubated, reared, and maintained as productive adults in high-density, artificial environments. Nevertheless, there are limits to adaptability as indicated by behavioral, physiological, immunological, and individual productivity indicators when environmental conditions become extreme. However, with the exception of obvious injury, no single criterion is likely to be adequate. Multiple indicators are required to obtain reliable evaluation of whether husbandry practices and environmental conditions reduce hens' welfare significantly. Concern for the well-being of hens has led to the phasing out of cages in two European countries. Although cages are known to be associated with some problems of well-being, it is known also that they have some welfare advantages for hens over alternative systems of production and they have definite economic advantages for producers. Therefore, it is doubtful whether the use of cages should be denied without exploring further the possibilities of cage modification or genetic selection aimed at improving the well-being of hens in such environments. Ethical perspectives relative to animals have been evolving since the time of Aristotle more than 300 yr B.C. Recent developments include divergence of welfare concerns between utilitarian and animal rights based philosophies. The utilitarians generally agree that animals may be used for human benefit if unnecessary pain and suffering are avoided and humane care and management criteria are met. Fundamentally, rights-oriented groups reject such exploitation. The general public exhibits a continuum of attitudes towards animals. However, there are indications that they are moving towards a protectionist attitude toward farm animals. Many requirements for good husbandry are known. However, uncertainty prevails in some areas, particularly with the necessity of routine procedures such as beak trimming and the amount of space needed, optimal group size, and whether nests, roosts, litter, and other quality of environment features are necessities or luxuries in terms of hens' welfare. Floor and feeder space and group size seem to be of paramount importance, and space that is adequate for well-being seems to be greater than that which yields the greatest net income. Genetic solutions to several behavior-related problems that compromise hens' well-being seem to be feasible and worthy of greater emphasis by commercial poultry breeders.

Animal Husbandry↗

PubMed1985

Prothrombin biosynthesis: characterization of processing events in rat liver microsomes.

Plasma and hepatic microsomal forms of rat prothrombin have been compared by sodium dodecyl sulfate-polyacrylamide electrophoresis and isoelectric focusing. The major prothrombin species that accumulated in the microsomes of rats treated with warfarin had a molecular weight of 78 500 and a pI in 8 M urea of 6.3-6.5. Plasma prothrombin had a molecular weight of 83 500 and a pI of 5.3-5.7. Microsomes from normal rat liver contain a second pool of precursor with a molecular weight of 83 500, and digestion with the glycosidase Endo H indicated that this form has been processed to contain complex carbohydrates, while the Mr 78 500 form is a high mannose form and is the substrate for the vitamin K dependent carboxylase. Treatment of rats with tunicamycin revealed that glycosylation was not essential for carboxylation or secretion from the liver. Comparison of the aglyco forms of prothrombin and its precursors suggests that the intracellular forms contain a basic, Mr approximately 1500 peptide that is missing from the plasma form of prothrombin.

Animals↗

PubMed1984

Abnormal prothrombin in the vitamin K-deficient rat.

Vitamin K is required for the post-translational formation of gamma-carboxyglutamyl residues in the vitamin K-dependent plasma clotting factors. Interference with vitamin K action results in the appearance of undercarboxylated, "abnormal," forms of prothrombin in bovine and human plasma, but the extent of this response in the rat has been controversial. Development of amidolytic and immunochemical assays for rat prothrombin have now shown that plasma from vitamin K-deficient or Warfarin-treated rats contains a non-BaSO4 adsorbable (undercarboxylated) pool of prothrombin that is equivalent to between 5 and 10% of the normal plasma prothrombin concentration.

Animals↗

PubMed1983

Vitamin K-dependent carboxylase: effect of detergent concentrations, vitamin K status, and added protein precursors on activity.

Activity of the rat liver microsomal vitamin K-dependent carboxylase has been studied at various concentrations of detergent. The activity which could be solubilized by 0.25% Triton X-100 was low but could be greatly increased if vitamin K-deficient rats were given vitamin K a few minutes before they were killed. At higher concentrations of Triton, more activity was solubilized and this effect was not seen. In vitro carboxylation of endogenous microsomal proteins was decreased by 80-90% if vitamin K was administered 1 min before rats were killed, but the amount of assayable prothrombin precursor was decreased by only 20%. Decarboxylated vitamin K-dependent rat plasma proteins were not substrates for the carboxylase and did not influence peptide carboxylase activity significantly. Purified microsomal prothrombin precursors did, however, stimulate carboxylation of peptide substrate and were used as a substrate for the carboxylase in a preparation from precursor depleted vitamin K-deficient rats.

Animals↗

PubMed1982

Vitamin K dependent in vitro production of prothrombin.

During prothrombin biosynthesis, glutamyl residues in prothrombin precursor proteins are carboxylated to gamma-carboxyglutamyl residues by a vitamin K dependent carboxylase. Calcium-dependent and calcium-independent rat prothrombin antibody subpopulations have been produced and utilized to study the liver microsomal precursors of prothrombin that accumulate when vitamin K action is blocked. A substantial portion of the precursor pool accumulating in the vitamin K deficient or warfarin-treated rat will react with a Ca2+-dependent antibody at high calcium concentration and appears to be partially carboxylated. During in vitro incubation in the presence of vitamin K, the fraction of the precursor pool which is tightly bound to the microsomal membrane appears to be the preferred substrate for the vitamin K dependent carboxylation. A small amount of completely carboxylated rather than a large amount of partially carboxylated products are produced during these incubations. Treatment with a Sepharose-bound prothrombin antibody demonstrated that about 20-25% of the total carboxylated microsomal protein precursor pool consists of prothrombin precursors. This treatment removes an equal amount of total carboxylase activity, and the enzyme is active in this carboxylase precursor-antibody complex.

Animals↗

PubMed1980