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Biomedical subjects

B K Nelson

Publications and source records attributed to B K Nelson.

At least 19 recordsLinked to original sources

Prospective, randomized trial of template-assisted versus undirected written recording of physician records in the emergency department.

STUDY OBJECTIVE: To determine whether use of the T-System (Emergency Services Consultants, Irving, TX) template-generated medical documentation system (1) decreases physician evaluation time in the emergency department, (2) increases gross billing under the 1997 Health Care Financing Administration guidelines by minimizing downcoding caused by inadequate documentation, and (3) increases physician satisfaction with the documentation process, compared with the undirected written narrative format. METHODS: A prospective, randomized, unblinded, controlled, convenience trial of documentation with the T-System of ED templates versus undirected written documentation was conducted in the ED of a county-owned, university-affiliated hospital. All patients seen between the hours of 7 AM and 10 PM during a 16-day period were included. The intervention was varying the method of documentation of the emergency physician. Adequacy of randomization to the 2 documentation groups was assessed by comparing ED triage classification, patient disposition, level of training of the evaluating physician, and whether ED consultation with other services occurred. Outcome measurements included emergency physician total evaluation and treatment time, professional bill, and satisfaction, as evaluated by a questionnaire completed after the study period. The 2 documentation groups were compared by an intention-to-treat analysis and by Student's t test and the median test as appropriate. RESULTS: A total of 1,228 patient encounters were included. Emergency physician total evaluation and treatment time with template-directed documentation was 4.6 minutes less than with undirected recording, a difference that was not significant (95% confidence interval [CI], -9.2 to 18.3). Gross billing was $29. 60 more per patient (95% CI, $22.20 to $37.00) with the T-System, as assessed by our hospital coders. This difference was caused by a mean.50 (95% CI,.39 to.60) higher level of evaluation and management coding. Physicians preferred the T-System (P <.0005). CONCLUSION: Use of template-assisted documentation in the ED was associated with higher gross billing and physician satisfaction but no significant decrease in emergency physician total evaluation time.

Attitude of Health Personnel↗

Preventive practicum training in healthcare organizations. The Meharry model.

BACKGROUND: Practicum training for preventive medicine residents often occurs in agencies whose community is geographically defined and whose governance is closely linked to public election. We were unsure about the financial ability of such departments to support training and are concerned that over-reliance on traditional health departments might not be best for either medically indigent populations or preventive medicine. We, therefore, sought to apply a public health model--based on a strategic partnership between nursing and preventive medicine--to a large health care organization. The result was formation of a mini-health department, suitable for fully accredited preventive medicine practicum training, within the Alvin C. York Veterans Affairs Medical Center, Murfreesboro, TN. This Center serves a defined population of 21,594 patients and about 1600 employees. The theoretical framework for the new department was based on demonstration of a close fit between the competencies expected of preventive medicine physicians by the American College of Preventive Medicine (ACPM) and activities required by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO). Because of JCAHO requirements, many healthcare organizations already pay for preventive medicine services. CONCLUSIONS: By placing preventive medicine training faculty into existing budget slots at our institution, systemwide personnel costs for prevention decreased by about $36,000 per year, even as personnel funding for preventive medicine physicians increased from about $24,000 to $376,000 per year. Moreover, there was dramatic, sustained improvement in 17 indicators of preventive care quality as determined by an external peer review organization. In addition to providing a new venue for training, this model may also improve the quality and reach of preventive services, decreased fixed costs for service delivery, and yield new employment opportunities for preventive medicine physicians.

Delivery of Health Care↗

Effect of environmental temperature on the interactive developmental toxicity of radiofrequency radiation and 2-methoxyethanol in rats.

OBJECTIVE: This research was conducted to determine if altered environmental temperatures would affect the interactive developmental toxicity of radiofrequency (RF) radiation and the industrial solvent, 2-methoxyethanol (2ME). This is important because RF radiation is used in a variety of workplaces that have poorly controlled environmental temperatures, and many workers are concurrently exposed to various chemicals. Furthermore, we have previously demonstrated that combined exposure to RF radiation (10 MHz) and 2ME produces enhanced teratogenicity in rats. METHODS: RF radiation sufficient to maintain colonic temperatures at the control value (38degrees ), 39.0degrees or 40.0 degrees C for 2 or 4 h combined with either 0 or 100 mg/ kg 2ME at environmental temperatures of 18 degrees , 24 degrees and 30 degrees C (65 degrees , 75 degrees , and 85 degrees F) were given on gestation day 13 to Sprague-Dawley rats. Dams were killed on gestation day 20, and the fetuses were examined for external malformations. RESULTS AND CONCLUSIONS: Environmental temperature does affect the specific absorption rate (SAR) necessary to maintain a specific colonic temperature but does not affect the interactive developmental toxicity of RF radiation and 2ME in rats. These results, consistent with the literature, add to the evidence that the developmental toxicity of RF radiation (combined or alone) is associated with colonic temperature, not with SAR.

Abnormalities, Drug-Induced↗

Statistical methodology: V. Time series analysis using autoregressive integrated moving average (ARIMA) models.

Most methods of defining a statistical relationship between variables require that errors in prediction not be correlated. That is, knowledge of the error in one instance should not give information about the likely error in the next measurement. Real data frequently fail this requirement. If a Durbin-Watson statistic reveals that there is autocorrelation of sequential data points, analysis of variance and regression results will be invalid and possibly misleading. Such data sets may be analyzed by time series methodologies such as autoregressive integrated moving average (ARIMA) modeling. This method is demonstrated by an example from a public policy intervention.

Analysis of Variance↗

Interactions of radiofrequency radiation-induced hyperthermia and 2-methoxyethanol teratogenicity in rats.

Radiofrequency (RF) radiation is used in a variety of workplaces. In addition to RF radiation, many workers are concurrently exposed to numerous chemicals; exposed workers include those involved with the microelectronics industry, plastic sealers, and electrosurgical units. The developmental toxicity of RF radiation is associated with the degree and duration of hyperthermia induced by the exposure. Previous animal research indicates that hyperthermia induced by an elevation in ambient temperature can potentiate the toxicity and teratogenicity of some chemical agents. We previously demonstrated that combined exposure to RF radiation (10 MHz) and the industrial solvent, 2-methoxyethanol (2ME), produces enhanced teratogenicity in rats. The purpose of the present research is to determine the effects of varying the degree and duration of hyperthermia induced by RF radiation (sufficient to maintain colonic temperatures at control [38.5], 39.0, 40.0, or 41.0 degrees C for up to 6 h) and 2ME (100 mg/kg) administered on gestation day 13 of rats. Focusing on characterizing the dose-response pattern of interactions, this research seeks to determine the lowest interactive effect level. Day 20 fetuses were examined for external and skeletal malformations. The results are consistent with previous observations. Significant interactions were observed between 2ME and RF radiation sufficient to maintain colonic temperatures at 41 degrees C for 1 h, but no consistent interactions were seen at lower temperatures even with longer durations. These data indicate that combined exposure effects should be considered when developing both RF radiation and chemical exposure guidelines and intervention strategies.

Abnormalities, Drug-Induced↗

Analysis of the treatment of spontaneous sustained stable ventricular tachycardia.

OBJECTIVES: To determine the termination rate of spontaneous sustained stable ventricular tachycardia (SSSVT) as a function of the first and second therapeutic interventions used, and to determine factors associated with successful termination. METHODS: A multihospital, retrospective analysis of the treatment of patients with SSSVT was performed. The setting included 2 urban county hospitals, 2 urban private hospitals, and a Veterans Affairs hospital. Cases were identified by discharge diagnosis and ECG characteristics, and confirmed by electrophysiology study or ECG criteria. RESULTS: There were 40 cases of SSSVT identified. Excluding adenosine, 35 patients were treated with lidocaine as a first intervention. The rate of termination with lidocaine bolus was 17% (6 of 35) (95% CI 7-34%). Regarding the 35 patients initially treated with lidocaine, the odds of termination of SSSVT were 11 times greater in those without a history of previous myocardial infarction (MI) than in those with a history of MI (95% CI 0.96-551). Of the 29 patients who failed initial lidocaine treatment, 23 were treated with a second lidocaine bolus, with a termination rate of 18% (4 of 22) (95% CI 5-40%). Only 2 patients with sustained ventricular tachycardia had a concurrent MI, and the tachycardia was unresponsive to initial lidocaine bolus in both cases. Fifteen patients received adenosine with no tachycardia terminations and no significant adverse effects. CONCLUSIONS: The rate of SSSVT termination with lidocaine was low, particularly in patients with a history of Mi.

Anti-Arrhythmia Agents↗

The IPCS Collaborative Study on Neurobehavioral Screening Methods: III. Results of proficiency studies. Steering Group.

The goal of the IPCS Collaborative Study on Neurobehavioral Screening Methods was to determine the intra- and inter-laboratory reliability of a functional observational battery (FOB) and an automated assessment of motor activity in eight laboratories world-wide. The first phase of the Collaborative Study involved training the participants: evidence of training was then evaluated using positive-control compounds. The positive-control studies required the laboratories to identify, using the FOB, specific neurotoxic syndromes produced by acute exposure to p,p'-DDT, parathion, and by short-term repeated dosing with acrylamide. For the sake of expediency, only one dose of each chemical was used instead of collecting dose-response data. Motor activity test chambers were not of uniform design. The laboratories were therefore required to demonstrate adequate sensitivity by the ability to detect statistically-significant activity increases and decreases produced by triadimefon and chlorpromazine, respectively, following acute administration of a range of doses. The resulting FOB and motor activity data showed variability in the magnitude of effects obtained: some of these differences were attributed to miscommunications, difficulties with the techniques or protocol, or the limitations of having only one dose. All laboratories, however, successfully met the criteria set forth by the Study Steering Committee.

Animals↗

The IPCS Collaborative Study on Neurobehavioral Screening Methods: IV. Control data. Steering Group.

The goal of the International Programme on Chemical Safety (IPCS) Collaborative Study on Neurobehavioral Screening Methods was to determine the intra- and inter-laboratory reliability of a functional observational battery (FOB) and an automated assessment of motor activity in eight laboratories worldwide. The control data were crucial to the outcome of the studies in terms of sensitivity and reliability of the test measures, which in turn impact on the between-laboratory comparisons of chemical effects. In addition, analyses of control data can aid in determining endpoints that may require modification to improve their sensitivity and reliability. The control data from the eight laboratories were examined in terms of the following parameters: 1) control variability within studies for each laboratory; 2) within-laboratory replicability of control values across studies; 3) within-laboratory stability of control values over the course of testing for a given study; and 4) between-laboratory comparisons of parameters (1), (2), and (3). The analyses indicated considerable differences across endpoints, wherein some measures showed high variability and little replicability, while others were extremely reproducible. Generally, there were similar ranges of variability and replicability of control data across laboratories, although in some cases one or two laboratories were markedly different from the others. The physiological (weight, body temperature) and neuromuscular (grip strength, landing foot splay) endpoints exhibited the least variability, whereas the subjective assessments of reactivity varied the most. These data indicate a reasonable degree of comparability in the data generated in the participating laboratories.

Animals↗

The IPCS Collaborative Study on Neurobehavioral Screening Methods: V. Results of chemical testing. Steering Group.

The IPCS Collaborative Study on Neurobehavioral Screening Methods was undertaken to determine the intra- and inter-laboratory reliability of a functional observational battery (FOB) and an automated assessment of motor activity in eight laboratories world-wide. Following the training phase and the conduct of proficiency studies in all laboratories, participants proceeded to test the effects of seven chemicals in both single dose and four-week repeated dosing scenarios. The chemicals studied were acrylamide, bisacrylamide, p,p'-DDT, lead acetate, parathion, toluene, and triethyl tin. Participants received coded samples from a common source. In order to judge the general utility of these procedures in a diversity of testing situations, laboratories conducted the studies under their standard conditions, using their choice of rat strain and test equipment. Chemical does and time of peak effect for acute testing were determined by each laboratory: these parameters were quite similar for some chemicals, but varied greatly for others. The results of the chemical tests indicated that while there was some variability in the data on specific endpoints, all laboratories detected and characterized the effects of all but one of the known neurotoxicants. The one exception (toluene) was probably due to other factors (e.g., dose level, route of administration) rather than lack of sensitivity of the test methods. This study provides extensive data regarding the use of neurobehavioral screening methods over a range of laboratory conditions as well as the reliability, sensitivity, and robustness of the tests to detect neurotoxic potential of chemicals.

Animals↗

Interactions in developmental toxicology: a literature review and terminology proposal.

Developmental toxicologists have investigated the interactive effects from concurrent exposures to a variety of chemical and physical agents, including therapeutic drugs, industrial agents, and some biological organisms or their toxins. Of approximately 160 reports of concurrent exposures reviewed in this paper, about one third report no interactive effects (including additive effects--usually referring to response--as opposed to dose-additivity); another one third report antagonistic effects, and the final third report potentiative or synergistic effects. The quality of the studies is highly variable. Frequently, only small numbers of animals were included, and very few dose levels were evaluated. Maternal toxicity was rarely discussed. Time-effect relationships were examined infrequently. In addition, these studies are also inconsistent in the use of terms to describe interactive effects, and more than 90% of the terms were not in harmony with currently accepted definitions in toxicology. Because interaction studies will continue to be important in the future, this paper proposes uniform usage of terms for additivity and interactions in developmental toxicology: additivity (the combined effect of two or more developmental toxicants approximates the sum of the effects of the agents administered separately); antagonism (the combined effect of two or more agents, one or more of which are present at doses that would be developmentally toxic if given individually, is significantly less than the sum of the effects of the agents administered separately); potentiation (the increased effect of a developmental toxicant by concurrent action of another agent at a dose that is not developmentally toxic); synergism (the combined effect of two or more developmental toxicants is significantly greater than the sum of the effects of each agent administered alone); and, interaction if more precise terminology does not apply.

Animals↗

Interactive developmental toxicity of radiofrequency radiation and 2-methoxyethanol in rats.

Concurrent exposures to chemical and physical agents occur in the workplace; exposed workers include those involved with the microelectronics industry, plastic sealers, and electrosurgical units. Previous animal research indicates that hyperthermia induced by an elevation in ambient temperature can potentiate the toxicity and teratogenicity of some chemical agents. We previously demonstrated that combined exposure to radiofrequency (RF; 10 MHz) radiation, which also induces hyperthermia and is teratogenic to exposed animals, and the industrial solvent, 2-methoxyethanol (2ME), produces enhanced teratogenicity in rats. The present study replicates and extends the previous research investigating the enhanced teratogenicity of combined RF radiation and 2ME exposures. The interactive dose-related teratogenicity of RF radiation (sham exposure or maintaining colonic temperatures at 42.0 degrees C for 0, 10, 20, or 30 min) and 2ME (0, 75, 100, 125, or 150 mg/kg) was investigated by administering various combinations of RF radiation and 2ME to groups of rats on gestation days 9 or 13; gestation-day 20 fetuses were examined for external, skeletal, and visceral malformations. The results are consistent with and extend our previous research findings. Synergism was observed between RF radiation and 2ME for some treatment combinations, but not for others. The study also clarified which gestational periods, RF radiation exposure durations, and 2ME doses would be most informative in future interaction studies to determine the lowest interactive effect level. Day 9 exposures generally evidenced little effect by 2ME, either by itself or in combination with RF radiation. In contrast, day 13 exposures resulted in highly significant effects from 2ME and RF radiation. The structures showing strong evidence of effects from both 2ME and RF radiation after exposure on gestation day 13 were the forepaw digits, forepaw phalanges, hindpaw digits, hindpaw phalanges, hind limbs, metacarpals, and metatarsals. Statistical analyses did not show a global synergistic effect, but did show evidence for a synergistic effect at intermediate levels of the dose ranges. Future research will address potential interactions at lower doses.

Abnormalities, Drug-Induced↗

Evidence for behavioral teratogenicity in humans.

Central to both the scientific development of behavioral teratology and the attention paid to this field as an important area of study is establishing that prenatal exposure of pregnant females to exogenous agents leads to neurobehavioral disorders in their offspring. This tenet may not be questioned by the majority of toxicologists, but others may not be convinced. This paper serves as a brief review of the accumulated evidence that prenatal exposure to a number of drugs and environmental/industrial agents produces behavioral disorders in human infants.

Behavior↗

Marked increase in the teratogenicity of the combined administration of the industrial solvent 2-methoxyethanol and radiofrequency radiation in rats.

Limited published animal research reports synergistic teratogenic effects following combined hyperthermia (induced by elevated ambient temperature) and administration of chemical teratogens. Radiofrequency (RF) radiation is widely used in occupational environments. Since RF radiation also elevates the body temperature of, and is teratogenic to, exposed animals, concurrent RF radiation and chemical agent administration may enhance teratogenicity. The present exploratory study, consisting of preliminary dose-finding studies and the primary study, was designed to investigate whether concurrent exposure of rats to RF radiation and the industrial solvent 2-methoxyethanol (2ME) can enhance the developmental toxicity of either agent acting alone. Preliminary dose-finding studies using small numbers of rats investigated the ability of various RF radiation conditions and doses of 2ME to produce external malformations (primarily of the paws) when administered on gestation day 13. Based on these preliminary studies, RF radiation exposure [sufficient to elevate rectal temperature to 42.0 degrees C (4 degrees C above normal for rats) for 30 min] and 2ME administration (150 mg/kg) were selected for the primary study. In the primary study, groups of 18 to 27 pregnant rats were administered RF radiation exposure and distilled water gavage, 2ME gavage and sham RF exposure, RF radiation exposure and 2ME gavage concurrently, or sham RF exposure and distilled water gavage. Pregnant rats were sacrificed on gestation day 20, and the offspring were examined for external malformations. Combined exposures enhanced the adverse effects produced by either experimental agent alone (no malformations were detected in the double sham group). Mean fetal malformations/litter increased from 14% after 2ME and sham RF (15/26 litters affected, with an average of 2 fetuses/litter malformed) and 30% after RF radiation and water gavage (10/18 litters affected, with an average of 4 fetuses/litter malformed), to 76% after the combined treatment (18/18 litters affected, with an average of 12 fetuses/litter malformed). In addition to a significant increase in the frequency of malformations, the severity of malformations also was enhanced by the combination treatment (on a relative severity ranking scale, the 2ME severity score was less than 1, the RF score was 3, and the combination score was 6). This study provided evidence of synergism between RF radiation and 2ME administration, but additional research will be required to characterize the extent of synergism between these two agents. Potential interactive effects between chemical and physical agents need to be investigated to determine the extent to which such interactions should impact occupational exposure standards.

Animals↗

Lack of selective developmental toxicity of three butanol isomers administered by inhalation to rats.

As part of an ongoing study of the developmental toxicology of industrial alcohols, this report presents the results of the teratology assessments of 1-butanol, 2-butanol, and t-butanol administered by inhalation to rats. Groups of approximately 15 Sprague-Dawley rats were exposed at 8000, 6000, 3500, or 0 ppm 1-butanol, 7000, 5000, 3500, or 0 ppm 2-butanol, or 5000, 3500, 2000, or 0 ppm t-butanol for 7 hr/day on Gestation Days 1-19 (sperm = 0). In each case, the highest concentration was selected to produce maternal toxicity. Dams were sacrificed on Gestation Day 20, and fetuses were individually weighed, tagged, and examined for external malformations. One-half of the fetuses were stained and examined for skeletal abnormalities, and the other half were examined for visceral defects using the Wilson technique. For each butanol isomer examined, the highest concentration (and the intermediate in some cases) was maternally toxic, as manifest by reduced weight gain and feed intake. Even at a maternally toxic dose, and in spite of a dose-dependent reduction in fetal weights for each isomer, the only teratogenicity observed was a slight increase in skeletal malformations (primarily rudimentary cervical ribs), seen with the highest concentration of 1-butanol. Thus, although teratogenicity was observed at 8000 ppm 1-butanol, and developmental toxicity was observed with each of the butyl alcohol isomers studied, concentrations 50 times the current permissible exposure limits for these three butanol isomers do not produce teratogenicity in rats.

Administration, Inhalation↗

Teratogenicity of n-propanol and isopropanol administered at high inhalation concentrations to rats.

As part of a teratological evaluation of several alcohols, 10,000, 7000 and 3500 ppm n-propanol or isopropanol were administered by inhalation to groups of 15 pregnant Sprague-Dawley rats for 7 hr/day on gestation days 1-19. The dams were killed on day 20. Half of the foetuses were examined for skeletal defects and the others for visceral defects using the Wilson technique. The highest concentration of n-propanol produced only minimal maternal toxicity, as indicated by observation and by measurement of weight gain and feed and water intake. In contrast, the same concentration of isopropanol produced narcosis in the dams, retarded body-weight gain and reduced the feed intake. At 7000 ppm isopropanol, body-weight gain was retarded but there were no other observable effects in the dams. Following exposure to 10,000 ppm of either alcohol, there were significant (P less than or equal to 0.05) increases in resorptions and decreases in foetal weights compared with the control groups. Foetal weights were also reduced significantly following exposure to 7000 ppm of either alcohol and to 3500 ppm isopropanol. Significantly more litters had malformations following exposure to 10,000 or 7000 ppm of either alcohol, but these effects were seen only in the presence of maternal toxicity. At 3500 ppm, no detectable teratogenic effects were produced by either solvent.

1-Propanol↗