Resistance to Fluopicolide and Propamocarb and Baseline Sensitivity to Ethaboxam Among Isolates of Pseudoperonospora cubensis From the Eastern United States

Chemical control is currently the most effective method for controlling cucurbit downy mildew (CDM) caused by Pseudoperonospora cubensis. Most commercial cucurbit cultivars, with the exception of a few new cucumber cultivars, lack adequate disease resistance. Fluopicolide and propamocarb were among the most effective fungicides against CDM in the United States between 2006 and 2009. Since then, reduced efficacy of these two fungicides under field conditions was reported starting around 2013 but occurrence of resistance to fluopicolide and propamocarb in field isolates of P. cubensis had not been established. Thirty-one isolates collected from cucurbits in the eastern United States were tested for their sensitivity to fluopicolide and propamocarb using a leaf disc assay. This same set of isolates and four additional isolates (i.e., 35 isolates) were also used to establish the baseline sensitivity of P. cubensis to ethaboxam, an ethylamino-thiazole-carboxamide fungicide, which was recently granted registration to control CDM in the United States. About 65% of the isolates tested were resistant to fluopicolide with at least one resistant isolate being present in samples collected from 12 of the 13 states in the eastern United States. About 74% of the isolates tested were sensitive to propamocarb with at least one resistant isolate being among samples collected from 8 of the 12 states in the study. The frequency of resistance to fluopicolide and propamocarb was high among isolates collected from cucumber, while the frequency was low among isolates collected from other cucurbit host types. All isolates tested were found to be sensitive to ethaboxam and EC₅₀ values ranged from 0.18 to 3.08 mg a.i./liter with a median of 1.55 mg a.i./liter. The ratio of EC₅₀ values for the least sensitive and the most sensitive isolate was 17.1, indicating that P. cubensis isolates were highly sensitive to ethaboxam. The most sensitive isolates to ethaboxam were collected from New York, North Carolina, and Ohio, while the least sensitive isolates were collected from Georgia, Michigan, and New Jersey. These results show that ethaboxam could be a viable addition to fungicide programs used to control CDM in the United States.

Carrying out the Medicine/Public Health Initiative: the roles of preventive medicine and community-responsive care

Leaders in medicine and public health, recognizing the inherent interdependency of these fields, established the Medicine/Public Health Initiative in the mid-1990s as "an evolving forum in which representatives of both sectors can explore their mutual interests in improving health and [can] define collaborative mechanisms to achieve that goal." The Initiative's participants developed six goals that they and others in medicine and public health across the nation should implement: engage the community; change the education process; create joint research efforts by clinical, public health, and preventive medicine investigators; develop a shared view of illness between medicine and public health; work together to provide health care; and work jointly to develop health care assessment measures. The authors describe the six goals in depth and explain the important combined roles of clinically-oriented preventive medicine and community-oriented preventive medicine--as practiced in a model of health care delivery called community-oriented primary care (COPC)--in implementing the Initiative's goals. They then report recent efforts, including two in Boston and Dallas, to merge medicine and public health, and state that academic health centers, which are in the process of reshaping themselves, can help themselves as well as the public by embracing their key role in the effort to integrate medicine and public health. In particular, they can expand and strengthen existing training programs in preventive medicine and COPC or add these programs to their curricula.

Attitudes of US primary care physicians about HIV disease and AIDS

Telephone interviews were conducted with 500 primary care physicians, drawn from a stratified random sample of internists, family practitioners, pediatricians, general practitioners, and OB/GYN physicians. Respondents were asked to report their experience treating AIDS patients and to estimate the percentage of their patients they felt were at high risk for HIV infection. Nineteen questions designed to assess practices and attitudes towards AIDS and HIV-related issues were asked. Results suggest that physicians underestimate their patients' level of risk for HIV infection and are not taking adequate drug use and sexual histories. The level of concern for personal risk of infection was high, although a strong ethical obligation to treat HIV patients was expressed. Physicians also expressed support for mandatory reporting and contact tracing, although this diminished as contact with HIV patients increased.

Faculty practice plans. Profile and critique

In 1910, the Flexner report signaled the end of commercialism in American medical schools, only to have it reappear in 1931. Between 1960 and 1985, access to federal, state, and private-sector funds paid to medical service plans in all 127 medical schools led to almost a 20-fold increase in faculty practice plan (FPPs)--from six to 118. All 127 US medical schools were surveyed. Wide swings in federal funding policies left medical schools with a defective management model, particularly for FPPs. Disposition of collected revenues, the role of for-profit FPPs, the personally lucrative nature of FPPs, an unwieldy number of fairly autonomous departments, ineffective governance, and hostile opposition from other parts of the university have raised questions of conflict of interest and accountability. Some 75 years after the Flexner report, a thorough evaluation of the effects of commercialism on medical education once again appears to be warranted.

Medicine and health care: implications for health sciences library practice

The American health care system is experiencing a period of unprecedented change. This paper identifies and discusses the major changes in patient care, research, control of the health care system, and medical education, and their implications for health sciences librarians. These changes have resulted in new demands for effective information delivery and a broader health sciences library clientele. There are both challenges and opportunities for health sciences librarians as they respond to information pressures of the current health care environment and anticipate future needs.

The University of Colorado School of Medicine

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Communications satellites in health education and health care provision. The WAMI experience

Since 1971, the University of Washington School of Medicine, Seattle, has operated a four-state, medical education program covering Washington, Alaska, Montana, and Idaho. This WAMI Program involves four universities without medical schools and 15 communities. To maintain this program, communication between the sites is imperative and mandates travel. The experiments described in this article were undertaken to determine whether full-duplex audio and color-video interactions via communications satellites could replace the travel requirements of the WAMI Program. Experiments involving the administration of the program, the presentation of the undergraduate medical education curriculum, the provision of health services, and the formation of public policies were conducted. The results suggest that satellite communication has broad applicability in medical education and health care provision.

Communication satellites: their role in medical education and health care delivery

This article describes an experiment in distance teaching/learning in large rural areas of North America using full duplex audiovisual interactive satellite communication. The effectiveness of the approach is compared with more conventional techniques in terms of regional faculty sharing, admissions and minority recruitment, the consultation process, independent learning and communication between public policy makers. Attention is paid to the cost and cost effectiveness of this form of communication.

Career preferences of first- and second-year medical students: the WAMI experience

Students admitted directly to the Seattle campus of the University of Washington School of Medicine are predominately from metropolitan areas. Students completing their first year at affiliated programs at Washington State University, University of Alaska, Montana State University, and the University of Idaho are predominately from nonmetropolitan areas. The authors compared these two groups of students with respect to preferred specialties and practice location; in addition, these preferences were examined on the basis of the size of students' home communities. Factor analysis of the preferences indicated by three entering classes at the end of their second year identified interpretable clusters of specialties and location types. Few differences were found in preferences for specialties, either between the groups or based on size of home community. Differences in attitudes toward location of practice indicated that students favor commmunities similar to those in which they were raised. The preferences indicated by second-year students were found to be significantly related to those expressed by the same students as they entered medical school, suggesting stability of student attitudes toward career choices. These results indicate that increased admissions from nonmetropolitan areas may affect the distribution of physicians by region but not by specialty.

Predicting first-quarter test scores from the new Medical College Admission Test

The predictive validity of the new Medical College Admission Test as it relates to end-of-quarter examinations in anatomy, histology, physiology, biochemistry, and "ages of man" is presented. It is recognized that the maximum predictive power is attenuated by the reliability of the criterion variables. To determine the value of attempting to increase the reliability in the criteria, the authors corrected the validity coefficients for attenutation. Regression analyses were also undertaken to examine the extent to which the new MCAT subtests can predict scores on end-of-quarter examinations. Results indicate that the Science Knowledge assessment areas of chemistry and physics and the Science Problems subtest were the most useful in predicting student performance, followed by the Skills Analysis: Quantitative and Skills Analysis: Reading subtests and the biology area of the Science Knowledge subtest.

The New Programmes: Decentralized Medical Education in the USA: The WAMI Programme

This article describes an experiment to provide decentralized medical education in Washington, Alaska, Montana and Idaho-four states sharing common problems of health care provision and education of health professionals, including physicians. Evaluation of eight years' experience with the programme shows that the goals are being met. The basic concept of the WAMI programme is applicable to other health disciplines and/or regions with similar geographic, financial, educational and health care challenges.

3H-uridine incorporation by small lymphocytes of tolerant rats: relationship to T and B lymphocytes

Tissue tolerance was induced in neonatal rats by the intravenous injection of bone marrow cells from adult allogeneic rat donors. After 6 to 8 weeks, lymphoid cells from rats in which tolerance had been induced were tested for mixed lymphocyte reactivity (MLR), 3H-uridine uptake, and the relationship of uridine incorporation to B and T lymphocytes. Lymph node (LN) and spleen (SPL) cells from the adult inoculated rats showed no reactivity in the MLR or normal lymphocyte transfer reaction (NLTRx), indicating that the animals were tolerant. After in vitro exposure to 3H-uridine, an abundance of small lymphocytes (SL) from these same tolerant rats were heavily labeled, in contrast to nontolerant controls, where relatively few SL were heavily labeled. In order to determine whether the heavily uridine-labeled cells were T cells or B cells, lymphoid cells from the LN and SPL of tolerant animals were exposed to either rabbit anti-AKR brain serum or rabbit anti-rat Ig conjugated with ferritin. The results showed that the heavily uridine-labeled SL of the tolerant rats were mainly Ig-positive cells.

The circulating life span, immunocompetence and 3H-uridine uptake of small lymphocytes from thymus-grafted, neonatally thymectomized rats

By 7 weeks post-grafting, the number of small lymphocytes in the thoracic duct lymph (TDL) and blood of the thymus-grafted neonatally thymectomized adult rats had increased to 60% of the number of cells in sham controls, or 2-1/2 times thymectomized control values. This increasing consisted almost exclusively of long-lived, recirculating small lymphocytes and corresponded to a 60% recovery of cellular immunocompetence as measured by the mixed lymphocyte reaction (MLR). Associated with the return of cellular immunocompetence was an increased incorporation of 3H-uridine by the small lymphocytes. Cells from thymectomized animals grafted with lymph node fragments demonstrated no significant increase in lymphocyte numbers nor was there a return of immunocompetence as compared to thymectomized controls.

Immunoglobulin-positive cells: their appearance in the mixed lymphocyte reaction

In mixed lymphocyte cultures prepared with thoracic duct lymphocytes from allogeneic rats, approximately 20 percent of all blast cells that appeared at the end of 72 hours of incubation had surface receptors for rabbit antibody to rat immunoglobulin.

Comparison of lymphocyte populations bearing surface immunoglobulins in avian bone marrow, bursa, spleen and thymus

Rabbit anti-chicken gamma-globulin was labeled with 125I and then incubated with cells from the bursa, thymus, spleen, and bone marrow of 4- and 8-week old birds. The same procedure was carried out on 11-week-old agammaglobulinemic chickens. Autoradiography revealed that the majority of large, medium, and small bursal lymphocytes bind the antibodies while labeled lymphocytes of each type in the spleen and thymus never exceeded 11 or 4 percent, respectively. Labeled medium and small lymphocytes in the bone marrow increased from 4.2 and 1.7%, respectively, at 4 weeks of age, to 9.5 and 8.8%, respectively, at 8 weeks of age. Labeled lymphocytes of all sizes were completely absent in all tissues of agammaglobulinemic chicks, including the marrow. Therefore, the increase in frequency of labeled lymphocytes in the bone marrow with age may be a result of recruitment of cells from the bursa of Fabricius. The majority of lymphocytes in the bone marrow do not label. Therefore, lymphocytes from the bone marrow may be T cells, subsets of B cells, or neither T or B cells.

Mixed lymphocyte reaction: an in vitro test for antilymphocytic serum activity

When Lewis rats were exposed to antilymphocytic serum, produced in rabbits, to Lewis lymphoid cells, the transformation of their thoracic duct lymphocytes in response to foreign lymphoid cells was markedly reduced in comparison with that in response to similar cells from donors treated with saline or normal rabbit serum. It is suggested that the mixed lymphocyte reaction may be used as an in vitro test for the in vivo activity of antilymphocytic serum.

The mixed lymphocyte reaction: an in vitro test for tolerance

Tolerance, as defined by an inability to produce runt disease and the failure to elicit a normal lymphocyte transfer reaction, was induced in Lewis and Brown Norway rats by the neonatal injection of bone marrow from the opposite strain. When thymus, thoracic duct lymph, or lymph node cells from such tolerant Lewis and Brown Norway rats were cultured together, or were individually cultured with similar cells from an F(1) hybrid of these strains, transformation was suppressed to the levels observed in nonmixed control cultures. In contrast, mixtures of cells involving nontolerant donors demonstrated significant transformation as measured by per cent enlarged cells and thymidine-(3)H uptake. The specificity of the tolerance was confirmed by the presence of transformed cells in mixtures involving cells from a tolerant donor and an unrelated or a partially related third strain of rats. From these results, it is suggested that the mixed lymphocyte reaction may be used as a simple test for tolerance and that it most likely represents an in vitro immune response.