Biomedical subjects

R L Bornschein

Publications and source records attributed to R L Bornschein.

43 records · Page 3Linked to original sources

PubMedDate not supplied

Assessment of reproductive disorders and birth defects in communities near hazardous chemical sites. I. Birth defects and developmental disorders.

Members of the workgroup on birth defects and developmental disorders discussed methods to assess structural anomalies, genetic changes and mutations, fetal and infant mortality, functional deficits, and impaired fetal and neonatal growth. Tier 1 assessments for all five adverse reproductive outcomes consist of questionnaires and reviews of medical records rather than laboratory testing of biologic specimens. The work-group members noted a role for neurodevelopmental testing and for limited genetic studies, such as karyotyping in Tier 2 assessments. Emerging methodologies to identify chromosomal aberrations, DNA adducts, and repair inhibition were reserved for Tier 3.

Adult↗

PubMedDate not supplied

Early exposure to lead and juvenile delinquency.

Cross-sectional studies have reported an association between lead (Pb) levels in bone and delinquent behavior in later childhood and adolescence. This is the first prospective longitudinal study of Pb and child development to address this question with comprehensive assessments of toxicant exposure and other developmental cofactors. A prospective longitudinal birth cohort of 195 urban, inner-city adolescents recruited between 1979 and 1985 was examined. Relationships between prenatal and postnatal exposure to Pb (serial blood Pb determinations) and antisocial and delinquent behaviors (self- and parental reports) were examined. Prenatal exposure to Pb was significantly associated with a covariate-adjusted increase in the frequency of parent-reported delinquent and antisocial behaviors, while prenatal and postnatal exposure to Pb was significantly associated with a covariate-adjusted increase in frequency of self-reported delinquent and antisocial behaviors, including marijuana use. Use of marijuana itself by Cincinnati Lead Study (CLS) teens was strongly associated with all measures of delinquent and antisocial behavior. This prospective longitudinal study confirmed earlier clinical observations and recent retrospective studies that have linked Pb exposure with antisocial behavior in children and adolescents. Both prenatal and postnatal exposure to Pb were associated with reported antisocial acts and may play a measurable role in the epigenesis of behavioral problems independent of the other social and biomedical cofactors assessed in this study.

Adolescent↗

PubMedDate not supplied

Role of exposure databases in epidemiology.

At present, exposure databases record data primarily for regulatory purposes; they have not focused on serving the needs of epidemiologists or public health. However, the modification of exposure databases could facilitate their use in epidemiology. Characteristics necessary to enhance the use of all databases include easy access by users; documentation of methods, sampling bias, error, and inconsistences; widespread coverage in time and space; and methods and measures for estimating exposure of individuals as well as populations. Also needed are exposure scenarios and models to estimate exposures for geographic areas and time intervals not currently sampled. Multidisciplinary teams are needed to examine current databases, to review strategies for improving data collection, and to suggest and help implement appropriate changes. A long-term goal is to develop and validate data from exposure scenarios and models using data on the relationship of exposure to doses measured in humans.

Databases, Factual↗

PubMedDate not supplied

Urinary arsenic excretion as a biomarker of arsenic exposure in children.

Urinary arsenic concentration has been used generally for the determination of exposure, but much concern has been raised over the most appropriate expression for urinary arsenic levels. In this study, we examined the influence of various adjustments of expressing urinary arsenic data. All children who were less than 72 mo of age and who were potty trained were invited to participate in the present study. Urine, soil, and dust samples were collected, and arsenic measurements were made. The geometric mean of speciated urinary arsenic among children who provided first-voided urine samples on 2 consecutive mornings was 8.6 microg/l (geometric standard deviation = 1.7, n = 289). Speciated urinary arsenic was related significantly to soil arsenic in bare areas (p < .0005). Use of a single urine sample versus the average of two first-voided urine samples collected on 2 consecutive mornings did not significantly alter the relationship between environmental arsenic and urinary arsenic levels. Furthermore, none of the adjustments to urinary concentration improved the strength of correlation between urinary arsenic and soil arsenic levels. Concentration adjustments may not be necessary for urinary arsenic levels obtained from young children who provide first-void samples in the morning.

Arsenic↗

PubMedDate not supplied

Behavioral consequences of prenatal diazepam exposure in rats.

Diazepam was administered to gravid rat dams on days 13 through 20 of gestation, at either 1 or 5 mg/kg/day. Pups were observed on several behavioral paradigms throughout the preweaning period. The high dose resulted in a failure to maintain weight gain at the same rate as controls. Additionally, this dose produced a deficit in the ability of 8-day-old pups to autonomically thermoregulate. Female littermates of these pups displayed altered habituation behavior on a holeboard apparatus when tested on postnatal day 12 (PN 12). The low dose attenuated the normal drop in body temperature produced by removal of the pup from its home cage on PN8. This dose also slightly decreased responding on a photocell activity task on PN15. Neither dose was found to affect muscle strength, as measured by hang time. The results suggest that the postnatal effects of prenatal diazepam exposure are dose-specific, in that low dose treatment leads to a different type of behavioral consequence than does exposure to higher doses.

Animals↗

PubMedDate not supplied

Behavioral and pharmacological responses following acrylamide exposure in rats.

The onset of acrylamide related toxicity and indications of recovery were evaluated using several behavioral tasks. Rats were chronically housed and tested for the first 15 weeks of the study in running wheels where food and water consumption and activity were continuously monitored. Separate groups of animals were repeatedly tested on at least one additional behavioral task: an operant schedule FR20 GO/NO-GO, spontaneous and drug-induced locomotor activity, drug-induced asymmetric rotation, or splaying of the hindlimbs. Animals were administered acrylamide monomer in their drinking water (100 ppm) for a six week period. Behavioral evaluations were initiated up to six weeks prior to acrylamide exposure and continued up to 12 weeks after termination of the exposure. Operant behavior and spontaneous locomotor activity in an open field were not affected by acrylamide exposure. Nocturnal activity in running wheels was decreased, and hindlimb splay increased by exposure to acrylamide. Subsequent to injections of d-amphetamine locomotor activity in an "open field" was markedly increased following exposure to acrylamide. d-Amphetamine induced asymmetric rotation was also altered following acrylamide exposure. It is suggested that this altered pharmacological response was due to an effect of acrylamide on hepatic mechanisms or on central dopaminergic function.

Acrylamides↗

PubMedDate not supplied

Functional implications of postural disequilibrium due to lead exposure.

Measurement of postural equilibrium has been employed as an indirect indicator of functional status of the nervous systems of 109 children (mean age: 5.8 +/- 0.78 years) from the Cincinnati Lead Program Project. The geometric mean blood lead for the first five years of life (PbB05) was 11.9 +/- 1.5 micrograms/dL. Postural sway associated with upright balance was noninvasively quantitated with a microprocessor-based force platform and four tasks performed for 30 sec each by the subjects. A covariate-adjusted multiple regression analysis showed statistically significant associations between PbB05 and the postural sway for the task requiring primarily vestibular and/or proprioceptive systems input, implying potential functional impairment. These findings raised several new issues which are addressed here: (1) A dynamic task has been developed to further test the effect of perturbing those afferents' functional capabilities. (2) A method has been developed to quantitate the stability boundary of each subject to better characterize the limits of functionally-safe postural sway. (3) There is a need to perform the postural sway in a shorter duration than 30 sec so that children younger than five years of age can be tested for early identification of Pb-induced functional impairment of postural equilibrium.

Child↗