1,212 research outputs found
Plumage Variation, Plasma Steroids and Social Dominance in Male House Finches
In male House Finches (Carpodacusm exicanus), the extent and color of plumage varies depending on access to carotenoid pigments. Colorful males exhibit extensive red pigmentation, while less colorful (i.e., drab ) males exhibit carotenoid pigmentation over a smaller percentage of their plumage, pigmentation of a color besides red (e.g., yellow, gold, orange, or pink), or both. One explanation for maintenance of plumage variation is that it reliably reflects social status, allowing males to correctly assess their status in relation to others and avoid or minimize costly fights. Social relationships may also be related to endogenous factors, such as circulating levels of the hormones testosterone and corticosterone. High levels of testosterone may promote or facilitate increased aggression, and stress associated with receiving aggression from individuals of higher status may increase adrenal activity and secretion of corticosterone.
We examined the relationship between plumage variability, steroid hormones, and social status in captive male House Finches during the non-breeding period in: (1) groups of males in which individuals varied by age, size, and plumage, and (2) pairs (dyads) of males matched for several measurable parameters except plumage. Testosterone and social status were not related in males competing in either groups or dyads, and levels of testosterone were routinely low. Corticosterone and status were not related in groups but, in dyads where subordinate individuals had little chance of escaping aggression from more dominant birds, subordinates exhibited significantly greater levels of corticosterone. Although drab males tended to achieve higher status than colorful males in both experiments, which is consistent with previous studies on free-living individuals, we could not reject the null hypothesis that plumage and status were unrelated. We conclude that dominance relationships among male House Finches during the non-breeding season may not be related to testosterone, but they are reflected by levels of corticosterone in some circumstances. Additionally, colorful plumage appears to be a poor predictor of high social status among male House Finches during the non-breeding season
Metabolism of [p-180]-Phenacetin: The Mechanism of Activation of Phenacetin to Reactive Metabolites in Hamsters
Induction of Colonic Aberrant Crypts in Mice by Feeding Apparent N-Nitroso Compounds Derived From Hot Dogs
Nitrite-preserved meats (e.g., hot dogs) may help cause colon cancer because they contain N-nitroso compounds. We tested whether purified hot-dog-derived total apparent N-nitroso compounds (ANC) could induce colonic aberrant crypts, which are putative precursors of colon cancer. We purified ANC precursors in hot dogs and nitrosated them to produce ANC. In preliminary tests, CF1 mice received 1 or 3 i.p. injections of 5mg azoxymethane (AOM)/kg. In Experiments 1 and 2, female A/J mice received ANC in diet. In Experiment 1, ANC dose initially dropped sharply because the ANC precursors had mostly decomposed but, later in Experiment 1 and throughout Experiment 2, ANC remained at 85 nmol/g diet. Mice were killed after 8 (AOM tests) or 17–34 (ANC tests) wk.Median numbers of aberrant crypts in the distal 2 cm of the colon for 1 and 3 AOMinjections, CF1 controls, ANC (Experiment 1), ANC (Experiment 2),and untreated A/J mice were 31, 74, 12, 20, 12, and 5–6, with P < 0.01 for both ANC tests. Experiment 2 showed somewhat increased numbers of colonic mucin-depleted foci in the ANC-treated group. We conclude that hot-dog-derived ANC induced significant numbers of aberrant crypts in the mouse colon
Limiting Federal Agency Preemption: Recommendations for a New Federalism Executive Order
The structure of the U.S. Constitution reflects a profound respect for the principles of federalism and state sovereignty. These principles require the federal government to recognize and encourage opportunities for state and local governments to exercise their authority, especially in areas of traditional state concern such as the protection of the health, safety, and welfare of their citizens. However, over the last six years there has been a coordinated Executive Branch effortto use the regulatory process to shield certain product manufacturers from state tort liability. The Food and Drug Administration, National Highway Traffic Safety Administration, and Consumer Product Safety Commission, among others, have attempted to use the doctrine of preemption to block consumers’ access to state courts. During the Bush Administration, executive agencies have included assertions of preemption in regulatory preambles, filed amicus briefs in litigation in which other litigants have argued that federal statutes preempt state law, and submitted to Congress draft legislation that would preempt state and local authority to protect public health, safety, and the environment.
The Obama administration should replace Executive Order 13132, which instructs administrative agencies to consider the federalism implications of their actions, with an Executive Order that is more protective of the legitimate interests of state governments in maintaining their traditional role in protecting the health, safety and welfare of their citizens. While the current order has some desirable features, it is inadequate to prompt the type of deliberations in which agencies should engage when they are considering whether to support the preemption of state law
3. Launching the New Enterprise
As the academic year of 1945-46 approached, the intensity of activity in preparation for actually opening the school in the fall term became overwhelming. Incredible though it may seem, Ives and Day were able in a period of a few weeks to assemble the nucleus of a faculty, several of whom formed a continuing source of counsel and advice both during the school’s formative years and thereafter. Includes: The First Dean and the School’s Dedication; A Participant’s View of the Early Years; Ives Moves On; Several Views of Martin P. Catherwood; The Founders
The Impact of Operation Bushmaster on Medical Student Decision-making in a High-Stress, Operational Environment.
INTRODUCTION: Operation Bushmaster is a high-fidelity military medical field practicum for fourth-year medical students at the Uniformed Services University. During Operation Bushmaster, students treat live-actor and mannequin-based simulated patients in wartime scenarios throughout the five-day practicum. This study explored the impact of participating in Operation Bushmaster on students\u27 decision-making in a high-stress, operational environment, a crucial aspect of their future role as military medical officers.
MATERIALS AND METHODS: A panel of emergency medicine physician experts used a modified Delphi technique to develop a rubric to evaluate the participants\u27 decision-making abilities under stress. The participants\u27 decision-making was assessed before and after participating in either Operation Bushmaster (control group) or completing asynchronous coursework (experimental group). A paired-samples t-test was conducted to detect any differences between the means of the participants\u27 pre- and posttest scores. This study was approved by the Institutional Review Board at Uniformed Services University #21-13079.
RESULTS: A significant difference was detected in the pre- and posttest scores of students who attended Operation Bushmaster (P \u3c .001), while there was no significant difference in the pre- and posttest scores of students who completed online, asynchronous coursework (P = .554).
CONCLUSION: Participating in Operation Bushmaster significantly improved the control group participants\u27 medical decision-making under stress. The results of this study confirm the effectiveness of high-fidelity simulation-based education for teaching decision-making skills to military medical students
Clinical Management of Metabolic Syndrome: Report of the American Heart Association/National Heart, Lung, and Blood Institute/American Diabetes Association Conference on Scientific Issues Related to Management
"The National Cholesterol Education Program’s Adult Treatment Panel III report (ATP III)1 identified the metabolic syndrome as a multiplex risk factor for cardiovascular disease (CVD) that is deserving of more clinical attention. Subsequently, the National Heart, Lung, and Blood Institute (NHLBI), in collaboration with the American Heart Association (AHA), convened a conference to examine scientific issues related to definition of the metabolic syndrome.2 The present report summarizes a second conference devoted to clinical management of the metabolic syndrome, which was sponsored by the AHA in partnership with the NHLBI and cosponsored by the American Diabetes Association (ADA). This latter conference considered the following issues: (1) pathogenesis and presentation of the metabolic syndrome, (2) management of underlying risk factors, (3) management of metabolic risk factors, and (4) unresolved issues and research challenges. The conference on definition2 confirmed CVD as a major clinical outcome of metabolic syndrome and identified 6 major components of the syndrome: abdominal obesity, atherogenic dyslipidemia, elevated blood pressure, insulin resistance ± glucose intolerance, a proinflammatory state, and a prothrombotic state. The follow-up conference on management was structured around therapies for these components. Clinical recognition of the metabolic syndrome is generally based on finding several well-recognized signs in clinical practice: abdominal obesity, elevated triglycerides, reduced HDL cholesterol, raised blood pressure, and elevated plasma glucose. In addition, research shows that other components not routinely measured commonly aggregate with the major components: elevated apolipoprotein B, small LDL particles, insulin resistance and hyperinsulinemia, impaired glucose tolerance (IGT), elevated C-reactive protein (CRP), and variation in coagulation factors (eg, plasminogen activator inhibitor [PAI]-1 and fibrinogen). The conference on definition2 also emphasized that risk for type 2 diabetes is higher in persons with metabolic syndrome and that diabetes is a major risk factor for CVD. It also examined various criteria for a clinical diagnosis of the metabolic syndrome. The diagnostic scheme developed by ATP III is shown in the Table. Clinical criteria proposed by the World Health Organization3 and American Association of Clinical Endocrinologists4 also were reviewed. These latter criteria overlap with those of ATP III but differ by requiring direct evidence of insulin resistance for diagnosis. Both the World Health Organization and the American Association of Clinical Endocrinologists recommend an oral glucose tolerance test (OGTT) in patients without an elevated fasting glucose. In other words, in the absence of impaired fasting glucose (IFG), IGT detected by OGTT is considered as one metabolic risk factor defining the metabolic syndrome. ATP III does not recommend OGTT in such persons, even through IGT is a high-risk condition for type 2 diabetes (independent of IFG) and correlates with increased risk for CVD. ATP III, however, held that the information gained by OGTT does not outweigh its costs and inconvenience in routine practice. The present conference on management moved from the issue of definition of the metabolic syndrome to the wide issues of clinical management.
- …