Monensin use against Neospora caninum challenge in dairy cattle.

Using a randomized controlled trial design, a randomly allocated intervention group of 15 cows received a slow-release bolus that delivered 100 days of monensin. The negative control group of 15 cows received a placebo bolus that was identical to the monensin bolus, except without the monensin. Two weeks after bolus administration, all cows were challenged with a 2 ml subcutaneous injection of a live tachyzoite suspension. Whole blood and serum samples were collected from each cow every week for the first month post-challenge, and then every 2 weeks for the next 2 months. The extracted DNA from whole blood was tested for the Nc-5 gene fragment of Neospora caninum using a quantitative real time polymerase chain reaction. Serum was tested for antibodies to N. caninum using the IDEXX ELISA. Cows treated with monensin boluses had a significantly lower humoral immune response than cows treated with placebo boluses at one time point post-challenge (week 4 post-challenge). However, when adjusting for repeated measures within cows, the P value for this humoral difference was 0.098. No DNA for N. caninum was detected in either group, likely due to study design features.

Who is making lifestyle changes due to preventive health care information? A demographic analysis.

This paper sought to describe from a set of demographic and lifestyle characteristics, the person who is significantly and positively impacted by preventive health care (PHC) information. Based on past research, six two-part hypotheses (PHC information and lifestyle) were developed, with a total examination of 12 possible relationships. Five of the six hypotheses were at least partially accepted, as were eight out of the 12 possible relationships. In addition, there was at least one significant relationship with a demographic variable in 12 of the 13 lifestyle change variables. It can be said with confidence that persons who are seeking and are positively impacted by PHC information are better educated, have higher incomes, are female, usually older, and married. The most important lifestyle changes emanating from PHC information are "changes in eating habits," "having periodic physician checkups," "utilizing nutritional labeling," and "joining a health club or wellness center." "Changes in social life," "sleeping habits," "getting regular exercise," and "attendance at health fairs and seminars" were also associated with the utilization of PHC information, but to a lesser extent.

Assessing the agreement between Ostertagia ostertagi ELISA tests performed using the crude adult antigen and the adult and larval stage 4 excretory/secretory antigens.

The objective of this study was to determine the agreement between ELISA tests conducted using three O. ostertagia antigens: crude adult worm, larval stage 4 (L4) excretory/secretory (ES) and adult ES. This study was carried out on 289 Holstein cows from five herds in Prince Edward Island and one herd in Nova Scotia. Composite milk samples of these cows were collected (between May and September 2002) from the respective provincial laboratories and sent to the Atlantic Veterinary College where each sample was tested for antibodies to O. Ostertagi using an indirect microtitre ELISA test. Results were expressed as optical density ratio (ODR) values. Each milk sample was tested with three ELISA tests, with each test using a different O. ostertagi antigen. There was a slight rise in ODR values of both adult antigens, between May and August, with higher values obtained using the adult ES antigen. L4 ES ODR values were generally higher than those for both adult antigens during the study period, except for May. There was a more dramatic rise in L4 ES ODR values between May and August. Rises in ODR in May and end of July coincided with periods of mass maturation of L4 to adult worms. The results of the study showed that the concordance correlation coefficient (CCC) between tests performed using both ES and the crude antigens were low (crude adult versus adult ES=0.31, crude adult versus L4 ES=0.30). The highest CCC was observed between tests done using both ES antigens (CCC=0.56). Generally, the study results suggest that the antibody response (detectable by the ELISA) is mainly directed against ES antigens (especially L4) than the crude adult worm antigen.

Evaluation of the repeatability of a crude adult indirect Ostertagia ostertagi ELISA and methods of expressing test results.

An indirect enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against Ostertagia ostertagi using a crude adult worm antigen was evaluated using serum and milk samples from adult cows, as well as from bulk tank milk. Within and between plate repeatabilities were determined. In addition, the effects of factors such as antigen batch, freezing, preserving of the samples and somatic cell counts (SCCs) of the samples were evaluated. Raw optical densities (ODs) and normalized values were compared using the concordance correlation coefficient (CCC), the coefficient of variation (CV), Bland-Altman plots (BA). Based on raw OD values, there was a high repeatability within a plate (CCC approximately 0.96 and CV<10%). Repeatability between plates was evaluated following normalization of OD values by four methods. Computing normalized values as (OD-Nt)/(Pst-Nt), gave the most repeatable results, with the CCC being approximately 0.95 and the CV approximately 11%. When the OD values were higher than 1.2 and 0.3 for the positive and the negative controls, respectively, none of the normalization methods evaluated provided highly repeatable results and it was necessary to repeat the test. Two batches of the crude antigen preparation were evaluated for repeatability, and no difference was found (CCC=0.96). The use of preservative (bronopol) did not affect test results, nor did freezing the samples for up to 8 months. A significant positive relationship between ELISA OD for milk samples and SCC score was found. Therefore, the use of composite milk samples, which have less variable SCC than samples taken from each quarter, would be more suitable when the udder health status is unknown. The analytical methods used to evaluate repeatability provided a practical way to select among normalization procedures.

The changing perceptions of junior medical students about the current U.S. health care system after a seminar series.

In the last few years dramatic changes have occurred in the way health care is delivered and financed in the United States. Academic medical centers have been slow in helping students understand what these changes will mean. We developed a series of student-run seminars and attempted to study what effect these seminars had on the students' attitudes towards many aspects of the current health care environment. We used recent journal articles as the basis for a student-led seminar series addressing many issues in the current health care environment. A previously developed 33-item survey was administered to the students before and after the seminars to evaluate any changes that occurred in their attitudes towards the evolving health care system. The students' responses showed significant changes on eight of the items surveyed. These included a more negative feeling about non-physician health care providers, a greater appreciation of the need for physicians to become more actively involved with social issues, and a greater understanding of the financial aspects of medicine. After a student-led seminar series there were significant changes in students' attitudes regarding several aspects of the changing health care environment in the United States.

Documenting and comparing medical students' clinical experiences.

CONTEXT: The decentralization of clinical teaching networks over the past decade calls for a systematic way to record the case-mix of patients, the severity of diseases, and the diagnostic procedures that medical students encounter in clinical clerkships. OBJECTIVE: To demonstrate a system that documents medical students' clinical experiences across clerkships. DESIGN AND SETTINGS: Evaluation of a method for recording student-patient clinical encounters using a pocket-sized computer-read patient encounter card at a US university hospital and its 16 teaching affiliates during academic years 1997-1998 through 1999-2000. PARTICIPANTS: A total of 647 third-year medical students who completed patient encounter cards in 3 clerkships: family medicine, pediatrics, and internal medicine. MAIN OUTCOME MEASURES: Number of patient encounters, principal and secondary diagnoses, severity of diseases, and diagnostic procedures as recorded on patient encounter cards; concordance of patient encounter card data with medical records. RESULTS: Students completed 86 011 patient encounter cards: 48 367 cards by 582 students in family medicine, 22 604 cards by 469 students in pediatrics, and 15 040 cards by 531 students in internal medicine. Significant differences were found in students' case-mix of patients, the level of disease severity, and the number of diagnostic procedures performed across the 3 clerkships. Stability of the findings within each clerkship across 3 academic years and the 77% concordance of students' reports of principal diagnosis with faculty's confirmation of diagnosis support the reliability and validity of the findings. CONCLUSIONS: An instrument that facilitates students' documentation of clinical experiences can provide data on important differences among students' clerkship experiences. Data from this instrument can be used to assess the nature of students' clinical education.

Critical factors for designing programs to increase the supply and retention of rural primary care physicians.

CONTEXT: The Physician Shortage Area Program (PSAP) of Jefferson Medical College (Philadelphia, Pa) is one of a small number of medical school programs that addresses the shortage of rural primary care physicians. However, little is known regarding why these programs work. OBJECTIVES: To identify factors independently predictive of rural primary care supply and retention and to determine which components of the PSAP lead to its outcomes. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: A total of 3414 Jefferson Medical College graduates from the classes of 1978-1993, including 220 PSAP graduates. MAIN OUTCOME MEASURES: Rural primary care practice and retention in 1999 as predicted by 19 previously collected variables. Twelve variables were available for all classes; 7 variables were collected only for 1978-1982 graduates. RESULTS: Freshman-year plan for family practice, being in the PSAP, having a National Health Service Corps scholarship, male sex, and taking an elective senior family practice rural preceptorship (the only factor not available at entrance to medical school) were independently predictive of physicians practicing rural primary care. For 1978-1982 graduates, growing up in a rural area was the only additionally collected independent predictor of rural primary care (odds ratio [OR], 4.0; 95% CI, 2.1-7.6; P<.001). Participation in the PSAP was the only independent predictive factor of retention for all classes (OR, 4.7; 95% CI, 2.0-11.2; P<.001). Among PSAP graduates, taking a senior rural preceptorship was independently predictive of rural primary care (OR, 2.5; 95% CI, 1.3-4.7; P =.004). However, non-PSAP graduates with 2 key selection characteristics of PSAP students (having grown up in a rural area and freshman-year plans for family practice) were 78% as likely as PSAP graduates to be rural primary care physicians, and 75% as likely to remain, suggesting that the admissions component of the PSAP is the most important reason for its success. In fact, few graduates without either of these factors were rural primary care physicians (1.8%). CONCLUSIONS: Medical educators and policy makers can have the greatest impact on the supply and retention of rural primary care physicians by developing programs to increase the number of medical school matriculants with background and career plans that make them most likely to pursue these career goals. Curricular experiences and other factors can further increase these outcomes, especially by supporting those already likely to become rural primary care physicians.

The failure of selenium supplementation to prevent copper-induced liver damage in Fischer 344 rats.

This study evaluates the ability of selenium (Se) supplementation to prevent experimental copper (Cu)-induced hepatocellular damage. Weanling male Fischer 344 rats were randomly assigned to groups of 15, 3 groups (A,B,C) were fed Cu-loaded diets (containing 2000 microg/g copper, added as CuSO4) and different levels of Se (added as Na2SeO3 x 5H2O) as follows: A) Cu-loaded/Se adequate diet (0.4 microg/g Se, fed basis); B) Cu-loaded/Se-supplemented diet (2 microg/g Se); and C) Cu-loaded/Se-deficient diet (< 0.2 microg/g). Three additional groups (D,E,F) were fed diets containing adequate levels of Cu (14 microg/g Cu, fed basis) and different levels of Se as follows: D) Cu-adequate/Se-adequate diet; E) Cu-adequate/Se-supplemented diet (2 microg/g Se); and F) Cu-adequate/Se-deficient (< 0.2 microg/g) diet. After 4, 8, and 12 weeks on the experimental diets, liver samples were processed for histology, histochemistry, metal analysis, glutathione peroxidase (GSH-Px) measurement, and quantification of malondialdehyde (MDA). Morphologic changes characteristic of Cu-associated hepatitis, without an increase in hepatic MDA levels, were seen in all Cu-loaded rats in each sampling. Similar changes occurred in rats fed Se-adequate, Se-supplemented and Se-deficient diets. This study demonstrates that Fischer 344 rats fed 2000 microg/g Cu develop morphologic changes due to Cu toxicity without evidence of lipid peroxidation. Furthermore, Se supplementation does not result in protection against Cu-induced liver injury.

Morphological and biochemical assessment of the liver response to excess dietary copper in Fischer 344 rats.

The aim of this study was to determine the amount of excess dietary copper (Cu) necessary to experimentally induce liver lesions characteristic of Cu-associated disease in Fischer 344 rats. Male weanling Fischer 344 rats of uniform age were divided into 6 groups (n = 5) and fed a rodent diet containing 18 (control), 750, 1000, 1250, 1500, and 2000 microg/g Cu added as CuSO4. Rats were euthanized after 3 months on the experimental diets and their livers processed for histology, histochemistry, Cu analysis (by atomic absorption spectrophotometry), and quantification of malondialdehyde (MDA) by the thiobarbituric acid reaction. Hepatic Cu levels were significantly higher (P < 0.01) in rats receiving over 1000 microg/g Cu compared to the controls (means for each diet: control = 4.8 microg/g, 750 microg/g Cu = 39.6 microg/g, 1000 microg/g Cu = 111.2 microg/g, 1250 microg/g Cu = 389 microg/g, 1500 microg/g Cu = 509.4 microg/g, and 2000 microg/g Cu = 766 microg/g). Histological lesions increased gradually according to the level of dietary Cu. Significant morphologic changes (necrosis, portal inflammation, hyaline remnants) and reduced growth rate occurred in rats receiving over 1250 microg/g Cu. However, no significant differences were found for MDA levels between groups. The present study demonstrates that compared to other species, very high levels of excess dietary Cu are needed to induce significant liver injury in Fischer 344 rats. Increased MDA content was not detected in rats with morphologic evidence of liver damage, suggesting that lipid peroxidation may not play a major role in this model of Cu toxicity.

The use of conjoint analysis to study patient satisfaction.

Previous research has identified aspects of the outpatient interactions between patients and physicians that are important for patient satisfaction. In this study, conjoint analysis was used to determine the relative importance of these factors to patients. This study found the perceived skill of the physician to be the most important factor and waiting time in the office the least important. The use of conjoint analysis should help both patients and physicians to maximize patient satisfaction while minimizing costs as much as possible.

A program to increase the number of family physicians in rural and underserved areas: impact after 22 years.

CONTEXT: The shortage of physicians in rural areas is a longstanding and serious problem, and national and state policymakers and educators continue to face the challenge of finding effective ways to increase the supply of rural physicians. OBJECTIVE: To determine the direct and long-term impact of the Physician Shortage Area Program (PSAP) of Jefferson Medical College (JMC) on the rural physician workforce. DESIGN: Retrospective cohort study. PARTICIPANTS AND SETTING: A total of 206 PSAP graduates from the classes of 1978 to 1991. MAIN OUTCOME MEASURES: The PSAP graduates currently practicing family medicine in rural and underserved areas of Pennsylvania, compared with all allopathic medical school graduates in the state, and with all US and international allopathic graduates. All PSAP graduates were also compared with their non-PSAP peers at JMC regarding their US practice location, medical specialty, and retention for the past 5 to 10 years. RESULTS: The PSAP graduates account for 21% (32/150) of family physicians practicing in rural Pennsylvania who graduated from one of the state's 7 medical schools, even though they represent only 1% (206/14710) of graduates from those schools (relative risk [RR], 19.1). Among all US and international medical school graduates, PSAP graduates represent 12% of all family physicians in rural Pennsylvania. Results were similar for PSAP graduates practicing in underserved areas. Overall, PSAP graduates were much more likely than their non-PSAP classmates at JMC to practice in a rural area of the United States (34% vs 11%; RR, 3.0), to practice in an underserved area (30% vs 9%; RR, 3.2), to practice family medicine (52% vs 13%; RR, 4.0), and to have combined a career in family practice with practice in a rural area (21% vs 2%; RR, 8.5). Of PSAP graduates, 84% were practicing in either a rural or small metropolitan area, or one of the primary care specialties. Program retention has remained high, with the number of PSAP graduates currently practicing rural family medicine equal to 87% of those practicing between 5 and 10 years ago, and the number practicing in underserved areas, 94%. CONCLUSIONS: The PSAP, after more than 22 years, has had a disproportionately large impact on the rural physician workforce, and this effect has persisted over time. Based on these program results, policymakers and medical schools can have a substantial impact on the shortage of physicians in rural areas.

A method for introducing the concepts of chaos theory to medical students.

Chaos theory is beginning to find applications in the field of medicine. The theory of chaos should be introduced to students to help them as they make the transition from learning the scientific literature to actually applying this newly acquired knowledge in clinical situations. Chaos theory will give the students a powerful conceptual framework from which they can better understand the limits of predictability in clinical situations. Failure to understand the limits of predictability in chaotic natural systems will invariably lead to frustration in both patients and physicians.

Factors related to nurse retention and turnover: an updated study.

How to attract and retain hospital registered nurses (RNs) has become a recurring theme discussed by hospital boards, administrators and physicians in the U.S. This study seeks to provide current data on this situation. The exploratory research effort consisted of 13 depth interviews with physicians in a major metropolitan area in the southeastern U.S. and less formal discussions with six hospital nurse administrators. The formal research effort involved hand-delivering questionnaires to nurse administrators for distribution to nurses in six hospitals in the same region. The principle reasons nurses change jobs fall into four categories: salary or benefits, convenience, work schedule, and job-related stress. After one or more hospital moves the nurses become more satisfied. Hospital administrators should institute motivational and hospital commitment programs to improve retention/reduce turnover, e.g., work schedule rotation, work responsibility rotation, team approaches to health care and award/recognition programs.

Psychosocial beliefs of medical students planning to specialize in family medicine.

The psychosocial orientation of fourth-year medical students planning careers in family medicine was compared to those selecting other specialties using the Physician Belief Scale. This scale has shown that practicing family physicians have a greater psychosocial orientation than those in other specialties such as internal medicine. The current study was done to see whether students choosing family medicine already have this greater orientation before they begin training as residents. 664 fourth-year medical students received surveys during their senior year and 378 (57%) returned completed surveys. Female students had a significantly greater psychosocial orientation than their male peers, but there were no significant differences between students planning residencies in family medicine and those selecting other residencies. The greater orientation of family doctors would appear to be a product of further training and experience either during residency or later during the actual practice of family medicine.

Medical students' specialty choice and the need for primary care. Our future.

Recent changes in the health care environment have directed increasing attention to the recognized oversupply of specialists and relative lack of primary care physicians. Despite this imbalance and the need for more primary care physicians, US medical schools are not producing them in adequate numbers. To effect change in the production of primary care physicians, a comprehensive approach that addresses key factors in medical student specialty choice is needed. This article discusses such factors and how they affect medical students during the course of their training. Issues concerning primary care specialty choice and the physician work force are important to the development of the future US health care system.

Effect of oral supplements of vitamin A on the plasma retinol levels in calves and their immunological unresponsiveness.

Forty calves were used to evaluate the immune response effects induced by a wide range of dietary vitamin A intake levels. The immune response was not affected by the tested doses of vitamin A administered orally during a 56 day period. There was no change in plasma immunoglobulin concentrations and no difference in specific antibody titres following injection of keyhole limpet haemocyanin (KLH) at 10, 20 and 40 days of age. Some small and temporary variations were recorded in the plasma vitamin A concentration following daily oral administration of various doses up to 10,000 IU. Only oral supplementation of 20,000 IU of vitamin A daily over 50 days significantly increased the plasma level of vitamin A.

Effects of supplemental vitamins E and C on the immune responses of calves.

Two experiments were conducted to evaluate the effects of oral supplementation of vitamin C and vitamin E (alpha-tocopherol), alone and in combination, on immune responses of calves. In Experiment 1, 18 Holstein newborn female calves were supplemented with 0, 1, and 2 g/d of vitamin C from birth to 6 wk of age. Concentrations of ascorbic acid in blood plasma were significantly higher for supplemented calves than for control calves. No significant differences among treatments occurred in the concentrations of IgG1, IgG2, and titer to keyhole limpet hemocyanin. In Experiment 2, effects of oral supplementation of vitamins E and C on immune responses were studied using 18 Holstein female calves. Concentrations of alpha-tocopherol in blood plasma were significantly higher for supplemented than for control calves. The concentrations increased from birth to wk 1, and then very little change occurred from wk 1 to 6. Differences among treatments in the concentrations of IgG1, IgG2, IgM, and titer to keyhole limpet hemocyanin were not significant; however, concentrations of IgM in calves supplemented with vitamins E and C generally tended to be higher than those of control calves. Antibodies to keyhole limpet hemocyanin were higher at 6 wk than at 4 wk of age.