Management of comminuted mandibular fractures: report of case.
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Accidents, Traffic↗
Biomedical subjects
N C Freeman
Publications and source records attributed to N C Freeman.
The comprehensive examination.
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Dentistry↗
Quantification of children's hand and mouthing activities through a videotaping methodology.
A videotaping methodology has been developed for use in quantifying the types and frequencies of children's hand and mouthing activities that could lead to exposure to environmental pollutants via dermal and ingestion pathways. Twenty children in day care, ages 3-6 years and 10 children in residences, ages 2-5 years, were videotaped during their waking hours for 1 day. Parents of each child completed questionnaires for the purpose of evaluating the accuracy of parental reports of hand-to-mouth rates. Videotapes were translated as quantifiable activities by two trained observers whose reporting reliability was checked throughout the investigation. Results determined that reliability of the videotaping method was very good, even over a year post-training. From videotape data, the average hand-to-mouth frequency rate was determined to be 9.5 contacts/h. These values are considerably higher than the current default value of 1.56 contacts/h under consideration by the EPA.
Administration, Cutaneous↗
Responses to the region 5 NHEXAS time/activity diary. National Human Exposure Assessment Survey.
The time/activity diary developed for use in the National Human Exposure Assessment Survey (NHEXAS) was completed by 249 participants in the Research Triangle Institute/Environmental and Occupational Health Sciences Institute (RTI/EOHSI) NHEXAS population-based pilot project conducted in the upper Midwest (EPA Region 5). The majority of participants successfully completed the diary during the 6-day study period. Participant responses showed internal consistency between related questions within the diary and between instruments used within the study. Comparison of response rates with the National Human Activity Pattern Survey, a nationwide population-based study, found consistent results when the same questions were used in both studies. Several questions identified age-specific activities. The value of the 6-day diary over 1-day surveys was apparent in discriminating between episodic and regularly conducted activities and in identifying subpopulations whose behavior may contribute to exposure to environmental pollutants.
Adolescent↗
Design strategy for assessing multi-pathway exposure for children: the Minnesota Children's Pesticide Exposure Study (MNCPES).
Although children are exposed to a variety of environmental hazards, including pesticides, there is a scarcity of information available to estimate exposures realistically. This article reports on one of the first attempts to measure multi-pathway pesticide exposures in a population-based sample of urban and non-urban children. A design strategy was developed to assess multi-pathway pesticide exposures in children using personal exposure measurements in combination with complimentary measurements of biological markers of exposure, concentrations in relevant environmental media, and time spent in important microenvironments and participating in exposure-related activities. Sample collection and analysis emphasized measurement of three insecticides (i.e., chlorpyrifos, diazinon, and malathion) and one herbicide (i.e., atrazine). These compounds were selected because of their frequent use, presence in multiple environmental media, expected population exposures, and related hazard/toxicity. The study was conducted during the summer of 1997 in Minnesota and involved a stratified sample of households with children ages 3-12 years. Participants resided in either (a) the cities of Minneapolis and St. Paul (urban households), or (b) Rice and Goodhue Counties just south of the metropolitan area (non-urban households). Results from a residential inventory documenting storage and use of products containing the target pesticides were used to preferentially select households where children were likely to have higher exposures. The study successfully obtained pesticide exposure data for 102 children, including measurements of personal exposures (air, hand rinse, duplicate diet), environmental concentrations (residential indoor/outdoor air, drinking water, residential surfaces, soil), activity patterns (obtained by questionnaire, diary, videotaping), and internal dose (metabolites in urine).
Biomarkers↗
Pesticide exposure and creatinine variation among young children.
Pesticide exposure may differentially impact young children; they live closer to the ground and take in greater amounts of food relative to body mass than older children or adults. We are using an organophosphate (OP) urinary biomarker screen (gas chromatography with flame photometric detection, GC/FPD) to evaluate pesticide exposure among 154 children < or = 6 years of age living in a heavily farmed border (US-Mexico) community. The screen detects diethylphosphates (DEPs) and dimethylphosphates (DMPs) above a reference range of 1000 non-occupationally exposed individuals (DL=25 microg/g creatinine, Cr). At least one metabolite was detected for 33% of the subjects; many samples contained multiple biomarkers. DEP was detected in 5% of the subjects. DMP and DMTP were frequently measured (25% and 26%, respectively). Biomarker concentrations are adjusted by the body's metabolism of Cr as an indicator of urine dilution. Cr concentrations were examined separately to evaluate their effect on internal dose measures. Cr concentrations were significantly different by season (K-W=0.83, P=0.022). Significant differences exist between the autumn:spring (P=0.038) Cr concentrations and between summer:autumn (P=0.041) Cr concentrations based on Mann-Whitney U=1070.5, z=-2.041, (P=0.041). Our analysis of NHANES III data did not reflect seasonal Cr differences for 6 year olds. No younger children were included. Absorbed daily dose (ADD) estimates were calculated for children with the highest concentrations of metabolite. Calculations are theoretical values assuming that the entirety of a given metabolite was metabolized from a single pesticide. Several class appropriate pesticides were evaluated. For the children with the highest levels, almost all estimated ADDs exceeded the RfD. Although the actual metabolite concentrations dropped appreciably, ADD were still exceeded RfDs at the 95th percentile. The urinary OP screen was effective in identifying subjects with atypical internal doses. Daily Cr yield is a critical component in ADD calculations. Cr variability produces differences in internal dose measurement and estimates of ADD independent of exposure. Cr variability among young children needs to be examined, and caution should be applied when evaluating Cr adjusted internal doses for children.
Agriculture↗
Measurement of multi-pollutant and multi-pathway exposures in a probability-based sample of children: practical strategies for effective field studies.
The purpose of this manuscript is to describe the practical strategies developed for the implementation of the Minnesota Children's Pesticide Exposure Study (MNCPES), which is one of the first probability-based samples of multi-pathway and multi-pesticide exposures in children. The primary objective of MNCPES was to characterize children's exposure to selected pesticides through a combination of questionnaires, personal exposure measurements (i.e., air, duplicate diet, hand rinse), and complementary monitoring of biological samples (i.e., pesticide metabolites in urine), environmental samples (i.e., residential indoor/outdoor air, drinking water, dust on residential surfaces, soil), and children's activity patterns. A cross-sectional design employing a stratified random sample was used to identify homes with age-eligible children and screen residences to facilitate oversampling of households with higher potential exposures. Numerous techniques were employed in the study, including in-person contact by locally based interviewers, brief and highly focused home visits, graduated subject incentives, and training of parents and children to assist in sample collection. It is not feasible to quantify increases in rates of subject recruitment, retention, or compliance that resulted from the techniques employed in this study. Nevertheless, results indicate that the total package of implemented procedures was instrumental in obtaining a high percentage of valid samples for targeted households and environmental media.
Adolescent↗
Dietary exposure of children in lead-laden environments.
Children are the most susceptible population to lead exposure because of three interacting factors; they have more opportunity for contact with lead sources due to their activities, lead absorption occurs more readily in a child compared to an adult, and the child's development is more vulnerable to lead than adults. Low levels of lead in the blood have been shown to cause adverse health effects; the level of concern for children is currently 10 microg/dl. The contribution of dietary exposure of lead to increased blood lead levels (PbB) is not well characterized. This study was conducted to measure potential dietary lead intakes of children 2 to 3 years of age who live in homes contaminated with environmental lead. Objectives were to estimate lead intakes for children consuming food in contaminated environments, recognizing unstructured eating patterns and to investigate if correlations exist between daily dietary exposure and measured PbB. Dietary exposure was evaluated by collecting samples that were typical of the foods the young children ate in their homes. A 24-h duplicate of all foods plus sentinel foods, i.e., individual items used to represent foods contaminated during handling, were collected from 48 children. Ten homes were revisited to obtain information on the variation in daily dietary intakes. Drinking water was evaluated both as part of the segregated beverage sample composite and by itself. Additional information collected included lead concentrations from hand wipes, floor wipes, and venous blood, and questionnaire responses from the caregiver on activities potentially related to exposure. Activities and hygiene practices of the children and contamination of foods in their environment influences total dietary intake. Estimated mean dietary intakes of lead (29.2 microg Pb/day) were more than three times the measured 24-h duplicate-diet levels (8.37 microg Pb/day), which were almost six times higher than current national estimates (1.40 microg Pb/day). Statistically significant correlations were observed between floor wipes and foods contacting contaminated surfaces, hand wipes and foods contacting contaminated hands and surfaces, and hand wipes and floor wipes. This study indicates that the dietary pathway of exposure to lead is impacted by eating activities of children living in lead-contaminated environments and that analysis of foods themselves is not enough to determine excess dietary exposures that are occurring.
Activities of Daily Living↗
Effect of vehicle use and maintenance patterns of a self-described group of sensitive individuals and nonsensitive individuals to methyl tertiary-butyl ether in gasoline.
The objective of this study was to compare the driving habits and vehicle maintenance patterns of individuals who report symptoms when exposed to methyl tertiary-butyl ether (MTBE) and those who are asymptomatic when exposed to the oxygenate. Participants were healthy volunteers (CON) and self-reported MTBE-sensitive individuals (SRS) who participated in a controlled exposure study of MTBE in gasoline. A questionnaire was developed to gather information about each participant's automobile usage, engine maintenance habits and fueling and driving patterns. Results showed that the individuals who had self-reported heightened sensitivity to the oxygenate drove their vehicles more often and fueled their vehicles more frequently than asymptomatic individuals. In addition, the self-reported symptomatic individuals in this study were shown to be more likely to drive vehicles with some form of body damage and carbureted engines.
Activities of Daily Living↗
Contribution of children's activities to lead contamination of food.
This study evaluates the relationship of children's hygiene habits and food-handling behaviors on lead levels on hands and handled foods for toddlers living in lead-contaminated homes. Forty-eight inner city toddlers previously identified as having elevated blood lead levels participated in three consecutive days of designated food-handling activities. During the visits, duplicate diets were obtained, the child handled a banana, a hot dog, and had his/her hands wiped with a moist towelette. In addition, wipe samples were collected from the kitchen floor, and food items were deposited on and subsequently collected from the kitchen floor. All samples were analyzed for lead. The child's caregiver completed a questionnaire, which addressed the child's hygiene and eating behaviors. It was demonstrated that children's contact with residential dust containing lead can transfer lead to food. Both lead in the home and on the children's hands contribute to the contamination of food, and hence potential dietary exposure. Mean lead in handled bananas was 26 microg/kg and on hot dogs 65 microg/kg, and mean lead values on cheese and apple slices that had been on the floor were 119 and 215 microg/kg. In addition, the child's hygiene habits as reported by the parent indicate that lack of basic hygiene patterns within a high lead environment can contribute to children's dietary exposure to lead.
Activities of Daily Living↗
Quantitative analysis of children's microactivity patterns: The Minnesota Children's Pesticide Exposure Study.
The National Human Exposure Assessment Survey (NHEXAS)/Minnesota Children's Pesticide Exposure Study (MNCPES) was a population-based study designed to characterize children's exposure to residential pesticides and to evaluate the contribution of residential and children's activities to children's exposure. Families of 168 children were surveyed for residential use of pesticides and children's activities. From these homes, families of 102 children between the ages of 3 and 13 years participated in a week-long intensive exposure study. Of the 102 children, 19 children were videotaped for four consecutive hours in their normal daily activities. The survey responses indicated that the youngest children were more likely to exhibit behaviors that would foster exposure to environmental contaminants. Comparison of questionnaire responses indicated that the videotaped subsample was representative of the exposure study population. The microactivities of the videotaped children that might contribute to their exposure via ingestion or dermal routes were quantified. Hand-to-mouth and object-to-mouth activities were observed most frequently among the youngest children. The youngest children were also most likely to be barefoot both indoors and outside. Gender differences were found in mouthing behavior and the proportion of observed time spent outdoors.
Activities of Daily Living↗
Exposure to chromium dust from homes in a Chromium Surveillance Project.
Investigators used a Lioy-Weisel-Wainman sampler to analyze the chromium content in house-dust samples obtained from households near chromium waste sites in Hudson County, New Jersey. Chromium concentrations in dust (microg/g)-indicative of non-background source contributions-were significantly higher in Jersey City homes than in control homes outside of Hudson County (228 and 111 microg/g, respectively; p < .001). Chromium dust loadings on surfaces (ng/cm2), representing the amount of chromium available for contact and a direct measure of exposure potential, were also higher in Jersey City homes than in control homes (31 ng/cm2 and 14 ng/cm2, respectively; p = .008). Near some of the sites, investigators found elevated chromium dust loads more frequently in homes occupied by at least one household member who had elevated urine chromium, as determined in a separate screening project, than in homes occupied by members whose urine chromium was not elevated. Individuals with elevated urine chromium levels were found less frequently in homes in which good housekeeping practices were evident than in homes absent such practices.
Chromium↗
Human blood types and dental caries experience.
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Adult↗
A portable datalogger to evaluate recall-based time-use measures.
Self-completed recall diaries have become a common tool in epidemiology and exposure assessment to determine the location and/or activities of subjects during study periods. Unfortunately, little effort has been made to determine the accuracy of such an approach for providing information without significant bias. It is usually assumed that subjects are truthful and complete in their recall. An electronic datalogger has been designed to allow subjects to record location changes as they occur in real time. Subjects carried the datalogger for 3-5 days and completed recall diaries at the end of each day. The concordance between the two records was found to be relatively good for the most commonly visited locations, e.g., bed/bath, workplace, etc. Poorer agreement was found for locations of short or infrequent visits, e.g., cellar or vehicle. The merits and shortcomings of the datalogger approach are discussed. While having external validation for recall diary records is clearly necessary, reliance on subject input to the datalogger presents its own problems related to subject compliance. Electronic approaches which do not require active subject input are recommended to aid in the evaluation of recall diaries.
Data Collection↗
Hygiene- and food-related behaviors associated with blood lead levels of young children from lead-contaminated homes.
Exposures associated with blood lead levels greater than 40 micrograms/dL in young children who live in lead-contaminated homes have been well documented. As the action level for lead is reduced, activities that contribute to lower levels of lead exposure must be identified. A child's eating habits and related hygiene behaviors are major hand-to-mouth activities that have been largely overlooked in the study of activities contributing to lead ingestion. To examine this subject, a survey questionnaire for caretakers of young children was developed. The objective of the questionnaire was to characterize food-related activities of young children and to identify behavioral indicators of lead exposure. The association between food- and hygiene-related behaviors and blood lead levels among 60 children between 13 and 36 months old with low-to-moderate blood lead levels was examined in homes that had been identified as containing lead in paint and house dust. The participants were enrolled in the Children's Lead Exposure and Reduction Study in Jersey City, New Jersey. Blood lead levels of children 13-24 months old did not differ significantly from those of children 25-36 months of age (10.1 and 11.3 micrograms/dL, respectively). Differences in eating habits and hygiene behaviors were found for the two age groups. Bivariate analyses found that the primary behavioral indicators of blood lead levels were determined by whether the child prepared his/her own food and whether the child ate food that had been on the floor. This factor was dependent on age. Children 13-24 months old had significantly elevated blood lead levels if these behaviors exhibited. No significant differences were found, however, for children 25-36 months old. Several food-related habits were also associated with blood lead levels. Eating hamburgers, doughnuts, peanut butter and jelly sandwiches, and cold cuts were associated with elevated blood lead levels in 13-24-month-old children, while eating vitamins, raw vegetables, and yogurt were associated with lower blood lead levels in this age group. For children 25-36 months old, eating hamburgers and peanut butter and jelly sandwiches was associated with elevated blood lead levels, while yogurt consumption was associated with lower blood lead levels.
Age Factors↗