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Biomedical subjects

J M Russo

Publications and source records attributed to J M Russo.

16 recordsLinked to original sources
PubMed2005

Verification of a European corn borer (Lepidoptera: Crambidae) loss equation in the major corn production region of the northeastern United States.

Field studies in Pennsylvania and Maryland were conducted during 2000, 2001, and 2002 to test the applicability of published yield loss relationships developed in central Pennsylvania for European corn borer, Ostrinia nubilalis (Hübner), management in warmer, longer season corn, Zea mays L., grain production regions of the northeastern United States. Both isoline hybrids and non-Bt lead hybrids were compared against Bacillus thuringiensis (Bt) hybrids to measure effects of the pest on yield. The European corn borer economic analysis model was used to make site-specific predictions of loss per European corn borer larva for comparison with measured yield loss per larva. Although the model did not predict loss per larva at a field level, it did predict loss at a regional level. The model predicted an overall percentage of yield loss per larva of 2.69+/-0.12% over the region, which was similar to the measured yield loss per larva of 2.66+/-0.59% for isoline hybrids and 3.08+/-0.51% for lead hybrids. The model, on average, provided a good prediction of percentage of yield loss per larva within the climatic zones of 1100-1700 degree-days (DD) (base threshold 12.5 degrees C). Our results suggest that the yield loss relationship developed in Central Pennsylvania, when matched to the timing of third instar second generation European corn borer stalk tunneling is adequate for major corn grain production zones of the northeast United States.

Agriculture↗
PubMed2000

Estimating disease risk at the whole plant level with General Circulation Models.

General Circulation Models (GCMs) have been developed to assess the impacts of potential global climate change. However, these models do not provide specific weather information at the whole-plant level and thus provide only very gross estimates of conditions that affect plant and disease development. Also, climatic change may increase the frequency of extreme events that influence plant production more than changes in daily or monthly averages. One solution is a simulation approach that can scale weather information from the global down to the plant scale. Over the last 4 years, we have been developing methods to hierarchically define current and forecast weather conditions down to the whole-plant level based on nested high-resolution atmospheric (mesoscale) numerical models. Two hierarchical mesoscale model approaches were tested to downscale weather data in a vineyard. The first, known as the Localized Mesoscale Forecast System (LMFS) uses surface databases to 'localize' mesoscale output. The second, known as the Canopy-Mesoscale Forecast System (CMFS), uses a boundary layer model to downscale mesoscale output. To illustrate the utility of this approach we focused on surface wetness duration (SWD), a variable with high spatial and temporal variability. SWD is also a critical variable for prediction of plant disease. Simulations of SWD with on-site input data were compared to those derived from the mesoscale models and to on-site sensors. Forecasts of atmospheric variables by the two systems were compared to on-site observations. Success in this effort leads us to extend this method to GCMs where factors such as temperature, rainfall, relative humidity, and surface wetness can be estimated within plant and crop canopies. We explore the implications of this work on evaluating the assessment of climate change on the risk of plant disease development.

Journal Article↗
PubMed1999

Evaluation of postural stability in workers exposed to lead at a secondary lead smelter.

Postural sway testing was carried out on a group of 145 workers exposed to lead in a secondary lead smelter and 84 workers not exposed to lead in a hinge manufacturing plant. All workers were measured for blood lead levels (BLL) and erythrocyte zinc protoporphyrin (ZPP) concentrations at the time of testing and both a total cumulative and a time-weighted average BLL value was constructed for the lead exposed workers. The lead exposed workers mean BLL at the time of testing was 38.9 microg/dl and the non-exposed workers mean was 2.3 microg/dl. ZPP levels averaged 55.2 microg/dl for exposed workers and 18.9 microg/dl for non-exposed workers. Total cumulative BLL averaged 83476 microg/dl days for the exposed workers, with a mean time-weighted average BLL of 35.1 microg/dl. Six tests of postural stability, four two leg conditions and two single leg conditions were administered to all subjects using a force platform to produce measurements of sway for comparison purposes. The two leg conditions also manipulated the visual and proprioceptive systems. A statistically significant association was observed for sway measurements and the current BLL for all workers, but not with the current BLL of only the lead exposed workers. No statistically significant associations were present with the cumulative measures of long-term exposure. Of the six tests of sway, only the single leg conditions showed significant exposure effects. The results suggest effects of lead exposure among those with average BLL near 40.0 microg/dl, but only in the most challenging one leg conditions.

Enzyme Inhibitors↗
PubMed1995

Evaluating unlicensed assistive personnel models. Asking the right questions, collecting the right data.

Although the popularity of unlicensed assistive personnel (UAP) models is evident by their implementation across the country, there has been very little scientifically based evaluation of their effectiveness. To facilitate better program evaluation, the authors review the current literature and outline a variety of data elements essential to effective UAP model evaluation. Major concepts that are addressed include program cost-effectiveness, customer satisfaction, patient outcomes, and evaluation of the success of both the training and implementation processes. Research questions that are pertinent to the model and need investigation also are presented. It is only through more thorough program evaluations that nurse executives can make informed decisions regarding the outcomes of care delivery restructuring efforts.

Cost-Benefit Analysis↗
PubMed1991

The University Hospital Nurse Extender Model. Part II, Program implementation.

This second article in a four-part series provides a detailed discussion of each phase of the implementation process, along with a demographic summary of the University Hospital Patient Care Technicians' Program 2 years after program implementation. Part I provided the overview and conceptual framework for the model. Parts III and IV will present the results of a year-long evaluation of the model and the lessons learned during the implementation process.

Female↗
PubMed1989

Wound healing. Oral and topical activity of Aloe vera.

The influence of Aloe vera, orally and topically, on wound healing was studied. Wounds were induced on both sides of the vertebral column of ICR mice using a biopsy punch. For the oral study, experimental animals received A. vera in their drinking water for 2 months, whereas the control animals received only water. In the topical study, experimental animals were given 25% A. vera in Eucerin cream topically. The control animals received cream only. A 62.5% reduction in wound diameter was noted in mice receiving 100 mg/kg/day oral A. vera and a 50.8% reduction was recorded in animals receiving topical 25% A. vera. These data suggest that A. vera is effective by both oral and topical routes of administration.

Administration, Oral↗
PubMed1989

Anti-inflammatory activity of Aloe vera against a spectrum of irritants.

The authors have evaluated the spectrum of anti-inflammatory activity of A. vera in a number of models of inflammation in the hind paw of the experimental rat induced by kaolin, carrageenan, albumin, dextran, gelatin, and mustard. Croton oil was used in a topical model of inflammation to determine the oral activity and time-dependent dosing of A. vera. The authors found that A. vera was active in all models of inflammation. Of the various irritants tested, A. vera was especially active against gelatin-induced and kaolin-induced edema and, in contrast, had minimal activity when tested against dextran-induced edema. Oral activity of A. vera was demonstrated to be dependent on the presence of anthraquinones. The various irritant-induced edema models provided a broad spectrum of anti-inflammatory activity for A. vera.

Aloe↗
PubMed1986

Neurobehavioral evaluation of soil and structural fumigators using methyl bromide and sulfuryl fluoride.

Neurobehavioral functions affected by methyl bromide exposure were evaluated in California structural and soil fumigators using methyl bromide and sulfuryl fluoride. Sampling data revealed that structural fumigators are exposed for up to 1.5 hrs/day to 0-2.2 ppm methyl bromide and/or 10-200 ppm sulfuryl fluoride, and soil fumigators can be exposed to 2.3 ppm methyl bromide over an 8-hr day. Subjects were grouped for statistical analysis on the basis of exposure history: Those exposed primarily (80% or more of the work period with exposure potential) to methyl bromide (N = 32), primarily to sulfuryl fluoride (24), or to a combination of methyl bromide and sulfuryl fluoride (40-60% of each) for a minimum of one year (18), and those not exposed to high concentrations of any chemicals (29 Referents). Fumigators using methyl bromide reported a significantly higher prevalence of 18 symptoms consistent with methyl bromide toxicity than did Referents. Methyl bromide fumigators did not perform as well as Referents on 23 of 27 behavioral tests (chosen to reflect methyl bromide effects), and were significantly lower on one test of finger sensitivity and one of cognitive performance. These consistent differences suggest that even the low levels of methyl bromide found in fumigation today may produce slight neurotoxic effects. found in fumigation today may produce slight neurotoxic effects. The greater number of symptoms and reduced performance on all cognitive tests in sulfuryl fluoride fumigators compared to the Reference Group plus the absence of published research on this compound suggest that the data base for sulfuryl fluoride is inadequate.

Adult↗
PubMed1984

Neurobehavioral assessment of chronic low-level methyl bromide exposure in the rabbit.

The research reported here was intended to identify the concentration at which methyl bromide begins to produce neurotoxic effects in the rabbit, a species known to be sensitive to this compound. Rabbits were exposed via inhalation to 27 ppm methyl bromide over a period of 8 mo for a total exposure duration of 900 h. Biweekly neurobehavioral tests, consisting of the latency rates of the ulnar and sciatic nerves and the amplitude of the eyeblink reflex of the orbicularis oculi muscle, failed to uncover any untoward consequences of the exposures. The rabbits gained weight and otherwise appeared to be healthy. In contrast to reports available in the literature, these findings suggest that long-term exposures to methyl bromide, in the present concentration range, are tolerated by this species. Also detailed in this report is the course of recovery of a separate group of rabbits previously given subchronic exposures to 65 ppm methyl bromide. These animals developed severe neuromuscular losses and had impaired blink reflexes and body weights. The symptoms partially subsided within 6-8 wk after removal from the exposures, suggesting that recovery from a nonfatal but seriously debilitating exposure is possible.

Animals↗
PubMed1981

Neurobehavioral effects of methyl bromide inhalation exposures.

Methyl bromide, a neurotoxic agent with a permissible US exposure limit of 20 ppm, is used primarily as a fumigant by an estimated 75,000 workers in the United States. This project was developed to evaluate the neurobehavioral effects of chronic and subchronic exposure to methyl bromide. One group of rats and rabbits was exposed to 65 ppm of methyl bromide for a total exposure of four 25-h weeks, or 100 h, and rats were exposed to 55 ppm of methyl bromide for a total exposure of 36 30-h weeks, or 1,080 h. Comparable control groups were given similar treatment, but no exposure. Behavioral tests of open field activity and limb coordination were conducted weekly during both phases of the experiment with rats, and eyeblink reflexes were measured weekly in rabbits. Nerve conduction velocity measurements were taken weekly from both rats and rabbits during the 65-ppm four-week exposures and monthly from rats during the 55-ppm 40-week exposures. Exposure to 65 ppm for four weeks significantly reduced eyeblink responses and nerve conduction velocity in rabbits but had no effect on rats. Exposure to 55 ppm of methyl bromide for 36 weeks had no effect on nerve conduction velocity, open-field activity, or coordination in rats.

Animals↗
PubMed1975

Combination rules for inhibitory stimuli.

Startle reactions are inhibited if their elicitation is preceded by weak neutral stimuli at lead times of fractions of a second, or by intense startle-eliciting stimuli at lead times of up to several seconds. In three experiments (a) two weak stimuli, (b) one weak stimulus and one intense stimulus, or (c) two strong stimuli were given in combination. In all three conditions the combination provided more response inhibition than did either stimulus alone. Conditions 1 and 2 gave combination effects in which the inhibited proportion of the response was described by the rule for compounding the probabilities of independent events, indicating that the stimuli had noncompetitive independent access to the inhibitory machinery. The rule over-estimated the effect of the compound in Condition c, suggesting the presence of some other summative process, perhaps involving the prolongation of the refractory period.

Acoustic Stimulation↗
PubMedDate not supplied

Neurobehavioral test methods for environmental health studies of adults.

The Agency for Toxic Substances and Disease Registry convened a workshop in Atlanta, GA, that evaluated approaches and methods to ascertain whether there are neurobehavioral sequelae to children and adults exposed to hazardous substances in the environment. This article, developed from that Workshop, recommends testing methods [to identify neurotoxic insult] for immediate use in environmental health field studies of adults. A list of broad functional domains or modalities affected by chemicals was identified from the occupational and related literature (learning and memory, coding, sustained attention, higher intellectual function, strength, coordination, speed, vision, somatosensory, and affect). A core set of tests was selected that should assess those functions with the greatest demonstrated sensitivity to established neurotoxic chemicals, and a secondary set was selected to assess a broader group of functions. The core tests should be used in all investigations where neurotoxic effects would be targeted for identification; secondary tests would be used where suggested by questionnaire or symptom data or by knowledge of the effects of chemicals at the hazardous waste site.

Adult↗
PubMedDate not supplied

A mathematical model of performance on a simple reaction time test.

A nonlinear function with components for learning and fatigue was used to model individual performance on a simple reaction time test. The relationships between the parameters of the model and the mean and variance of the reaction times are discussed. The function is used to analyze data from a field study of agricultural workers exposed to organophosphate pesticides. Exposure had a significant effect on the relationships between education level and initial performance, age and fatigue rate, and age and performance variability. Parameter estimates from the model were able to distinguish between effects that the mean and standard deviation of the reaction times were unable to distinguish.

Adolescent↗
PubMedDate not supplied

Neurophysiological and neuropathological evaluation of primates exposed to ethylene oxide and propylene oxide.

Over 500,000 workers in the United States are exposed to ethylene oxide and propylene oxide. These two solvents are used as chemical intermediates, as well as components in the manufacture of fumigants and food preparation. The neurophysiologic and neuropathologic effects of these two organic oxides were investigated in five groups of 12 primates after exposure to 50 or 100 ppm ethylene oxide, 100 or 300 ppm propylene oxide, or no chemical (sham-exposed). Animals were exposed for 7 h/day, 5 days/wk for 24 months. Body weights, electroencephalograms, and motor nerve conduction velocities of the sciatic and ulnar nerves were assessed six times throughout the exposure period. Although the monkeys exposed to 100 ppm ethylene oxide had significantly lower mean weights, nerve conduction velocities did not differ significantly among the groups. Following termination of exposures, ten animals (two from each exposure group) were sacrificed for neuropathological examinations. Multiple axonal bodies were found in the nucleus gracilis in seven of eight oxide-exposed animals, and demyelination was found in two monkeys exposed to ethylene oxide. In contrast, a single axonal body was found in one of the two sham-control monkeys. However, the lack of a dose-response relationship suggests that this effect may not be related to oxide exposure. In a follow-up study, nerve conduction velocity and neuropathology were assessed in the remaining monkeys seven years after exposure terminated, but again, treatment-related effects could not be detected.

Action Potentials↗