Development and field evaluation of a decision support model for anthelmintic treatments as part of a targeted selective treatment (TST) regime in lambs.

The recent focus of strategies to slow the rate of development of anthelmintic resistance in gastro-intestinal parasites has centred on the need to better manage the parasite population that is unexposed to the drug, i.e. in refugia. One strategy involves the use of targeted selective treatments (TST) where anthelmintics are only administered to those individuals that are likely to benefit from it, rather than to the whole flock. However, there are few TST indicators currently available for farmers in temperate environments. Here we describe the development and field evaluation of a performance-based decision support model to identify individual animals whose performance is suffering from nematodoses, and thus, likely to benefit from an anthelmintic treatment. One hundred and ninety two twin-suckled lambs were separated into eight groups and each grazed on a one-hectare paddock and exposed to one of four anthelmintic treatment regimes. Groups of lambs received either: a whole flock anthelmintic treatment either every four weeks (neo-suppressive treatment, NST); when clinical signs of disease were evident (metaphylactic/therapeutic treatment, MT); at pre-determined times throughout the grazing season (strategic treatment, SPT) or treatment on an individual animal basis as determined by a performance-based decision support model that relied on a calculation of the efficiency of nutrient utilization (targeted selective treatment, TST). Animal performance and parasitological data were recorded every two weeks. Mean faecal egg counts were low throughout the season for the NST group and moderate for the MT, SPT and TST groups. During the entire grazing season the NST, MT, SPT and TST animals each received on average 5.0, 2.0, 3.0 and 2.6 anthelmintic treatments, respectively. Compared to the NST animals, cumulative weight gains were 11% lower at the end of the grazing season in MT animals, whereas no reduction was observed in either the SPT or TST groups. The proposed decision support system appeared to be successful in discriminating between animals which were likely to respond favourably to anthelmintic treatment and those that were not and provided a quantitative estimate of the likely response. Furthermore, 87% of animals that had a pre-treatment efficiency of nutrient utilization value lower than the suggested threshold of the model responded positively to treatment. The potential benefits of using the decision support model as a TST indicator for managing the parasite population in refugia in temperate environments are discussed.

Metabolic regulation of aldose reductase activity by nitric oxide donors.

Regulation of aldose reductase (AR), a member of the aldo-keto reductase superfamily, by nitric oxide (NO) donors was examined. Incubation of human recombinant AR with S-nitrosoglutathione (GSNO) led to inactivation of the enzyme and the formation of an AR-glutathione adduct. In contrast, incubation with S-nitroso-N-acetyl penicillamine (SNAP) or N-(beta-D-glucopyranosyl)-SNAP (GlycoSNAP) led to an increase in enzyme activity which was accompanied by the direct nitrosation of the enzyme and the formation of a mixed disulfide with the NO-donor. To examine in vivo modification, red blood cells (RBC) and rat aortic vascular smooth muscle cells (VSMC) were incubated with 1 mM GSNO or SNAP. Exposure of VSMC to SNAP and GSNO for 2 h at 37 degrees C led to approximately 71% decrease in the enzyme activity with DL-glyceraldehyde as the substrate. Similarly, exposure of RBC in 5 mM glucose to NO-donors for 30 min at room temperature, followed by increasing the glucose concentration to 40 mM, resulted in >75% decrease in the formation of sorbitol. These investigations indicate that NO and/or its bioactive metabolites can regulate cellular AR, leading to either activation (by nitrosation) or inactivation (by S-thiolation).

Careers in academic medicine and clinical practice for minorities: opportunities and barriers.

The United States has a shortage of physicians from underrepresented minorities. Under-representation of ethnic minority academic faculty is due to multiple factors, including an inadequate number of minority medical school graduates, indebtedness of minority postgraduate trainees, lack of awareness of opportunities in academic medical centers, lack of mentors, a shortage of role models, and environmental factors. Over recent years, the government, private industry, and some universities and medical schools have made efforts to remedy this situation. The problems, however, are complex and difficult to solve. There is a need to increase the pool of underrepresented minority students interested in careers in medicine; to promote medical student, graduate student, and house staff awareness of career opportunities in academics; to provide resources that enable students, house staff, and fellows to develop the skills necessary to succeed and survive in the academic arena; and to offer ongoing support for career development of junior faculty. A number of programs exist for attracting more minorities to academic medicine, but obtaining information on them is often difficult. The development of a centralized resource center where program information is readily available should be a priority. An effort to coordinate activities of existing programs by the Institute of Medicine and/or the Association of American Medical Colleges (AAMC) is needed. A target goal should be developed for increasing minorities in graduate medical education and academic medicine similar to the AAMC's Project 3000 by 2000.

An assessment of the impact of radiofrequency interference on microwave SETI searches.

Investigations are carried out at JPL on radiofrequency interferences at very low levels (-130 to -180 dBm) in various bands, especially the 1-2 GHz band. Extrapolation of interferences in the years to come is attempted.

Physician influence on patient compliance: a clinical trial.

This study was designed to measure the effect of altering three possible impediments to care provided patients with non-emergency problems in a large city hospital emergency department: inadequate patient education by physician, lack of continuity of care, and complex and impersonal clerical procedures. Patients with symptomatic urinary tract infections were randomly assigned to intervention and control groups. A senior physician spent extra time with patients in the intervention group to discuss the assessment and management of their problem, bypass the usual clerical procedures at discharge, and promise continuity of care. Patients in the control group were treated in the usual fashion by emergency department nurses and residents. The return rate to the emergency department three weeks after the initial visit was used to measure the effect of the altered care applied to patients in the intervention group. Our hypothesis was that patients in the intervention group would be more likely to return. Of 46 patients in the intervention group 26 returned. Of 43 patients in the control group, 14 returned (chi square 4.23 after Yate's correction, 0.025 less than P less than 0.05). The significance of this improvement is discussed.

Blood acid-base regulation during environmental hyperoxia in the rainbow trout (Salmo gairdneri).

Blood acid-base balance, blood gases, respiration, ventilation, and renal function were studied in the rainbow trout during and following sustained environmental hyperoxia (PIO2 = 3.50-650 Torr). Animals were chronically fitted with dorsal aortic cannulae for repetitive blood sampling, oral membranes for the measurement of ventilation, and bladder catheters for continuous urine collection. Hyperoxia caused a proportional increase in arterial O2 tension and a stable 60% reduction in ventilation volume (Vw), the latter mainly due to a decrease in ventilatory stroke volume. O2 consumption exhibited a short-term elevation. Arterial CO2 tension (PaCO2) rose within 1 h, causing an immediate drop in arterial pH (pHa), and continued to increase gradually thereafter, reaching a value 2-4x the normoxic control level after 96-192 h. Compensation of the associated acidosis by the accumulation of [HCO3-] in the blood plasma started within 5-6 h, and was complete by 48 h. Therefore, further compensation occurred simultaneously with the gradual rise in PaCO2. The kidney played an important active role in this compensation by preventing excretion of the accumulated [HCO3-]. Upon reinstitution of normoxia, PaCO2 dropped to control levels within 1 h, and restoration of blood acid-base status by reduction of [HCO3-] had commenced by this time. A complete return to control values occurred within 20 h. During hyperoxia, an experimental elevation of the depressed Vw above control normoxic levels caused only a minor and transient reduction in PaCO2 and no change in pHa, but injection of branchial vasodilator 1-isoprenaline (10 mumol/kg) produced a large drop in PaCO2 and rise in pHa. It is concluded that the rise in PaCO2 during hyperoxia is mainly due to internal diffusive and/or perfusive limitation associated with branchial vasoconstriction, rather than to external convective limitation associated with the decreased Vw.

Use of drugs among persons admitted to a country jail.

Examinations of 427 prisoners at the time of the admission to a large urban county jail showed that more than a quarter were, or had been, users of potentially addictive drugs. Except for their drug problems, the drug users did not present any more of different health problems than the nonusers. The treatment for drug abuse recommended by the examining physicians was, for the most part, not available in the facility. Evidence of continued drug use in the jail by less than 10 per cent of the prisoners was obtained at 4-week and 8-week followup examinations. Detection of drug use by means of questionnaires and urine testing was shown to be feasible among persons admitted to such a jail.

Traditional criteria as predictors of minority student success in medical school.

There have been many reports stating that the traditional criteria of the Medical College Admission Test (MCAT) and undergraduate grade-point average (GPA) have little, if any, value in predicting success in the preclinical years of medical school among students from underrepresented (racial and ethnic) minority groups. In contrast to previous articles this report emphasizes that traditional criteria and the quality of the undergraduate college attended are of some statistical value in predicting success in the preclinical years of medical school among accepted students from under represented minority groups. Of these criteria, the one with the greatest predictive value is the selectivity of the undergraduate college attended.