Biomedical subjects

Francis W Kemp

Publications and source records attributed to Francis W Kemp.

5 recordsLinked to original sources

PubMed2006

Tissue lead concentration during chronic exposure of Pimephales promelas (fathead minnow) to lead nitrate in aquarium water.

The fathead minnow is a useful species for evaluating the toxicity of wastewater effluents. While this fish is widely used for "survival" studies of metal toxicity, little or no work has been done on the tissue distribution of metals in fathead minnows. To determine the distribution of tissue lead, aquarium studies were conducted for several weeks with fish maintained in soft synthetic freshwater. Lead- (II) nitrate was added to three aquaria attaining concentrations of 20-30 ppb (aquarium B), 100-140 ppb (aquarium C), and roughly 200 ppb (aquarium D). Results were compared to controls (aquarium A). During the initial week, the majority of aquarium D fish died, whereas few deaths occurred in the other groups. Lead accumulation was dose- and tissue-dependent, with highest uptake by the gills. Gill concentrations of aquarium D fish averaged about 4-fold higherthan in skeleton or skin and muscle. In vitro, lead (2.5-25 ppm) caused dose-dependent reductions in the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) in gills incubated in physiological buffer. These findings demonstrate that fathead minnow gills bind and accumulate waterborne lead rapidly and preferentially and raise the possibility that gill lipid peroxidation contributes to lead toxicity at low water hardness.

Animals↗

PubMed2005

Case of elevated blood lead in a South Asian family that has used Sindoor for food coloring.

After a routine blood testing, a local pediatrician discovered that a 13-month-old boy had an elevated blood lead level (BLL) of 57 microg/dL. Since the baby was mostly breast-fed, the pediatrician did a blood test on the mother, and the result showed a BLL of 85 microg/dL. As the mother denied any history of pica behavior, the pediatrician suspected a source of lead to which the entire family might have been exposed and tested the father's BLL. The results showed a BLL of 95 microg/dL, and the pediatrician informed the poison center. The subsequent epidemiological investigation revealed that the parents had used a product called Sindoor for food coloring. Laboratory analyses showed that the product contains more than 57.8% of acid-extractable lead by weight. Given the extremely high content of Pb in this product, Sindoor poses a serious risk of lead poisoning if it is used for food coloring.

Asian↗

PubMed2003

Lead exposure potentiates predatory attack behavior in the cat.

Epidemiologic studies have demonstrated that environmental lead exposure is associated with aggressive behavior in children; however, numerous confounding variables limit the ability of these studies to establish a causal relationship. The study of aggressive behavior using a validated animal model was used to test the hypothesis that there is a causal relationship between lead exposure and aggression in the absence of confounding variables. We studied the effects of lead exposure on a feline model of aggression: predatory (quiet biting) attack of an anesthetized rat. Five cats were stimulated with a precisely controlled electrical current via electrodes inserted into the lateral hypothalamus. The response measure was the predatory attack threshold current (i.e., the current required to elicit an attack response on 50% of the trials). Blocks of trials were administered in which predatory attack threshold currents were measured three times a week for a total of 6-10 weeks, including before, during, and after lead exposure. Lead was incorporated into cat food "treats" at doses of 50-150 mg/kg/day. Two of the five cats received a second period of lead exposure. Blood lead concentrations were measured twice a week and were <1, 21-77, and <20 micro g/dL prior to, during, and after lead exposure, respectively. The predatory attack threshold decreased significantly during initial lead exposure in three of five cats and increased after the cessation of lead exposure in four of the five cats (P<0.01). The predatory attack thresholds and blood lead concentrations for each cat were inversely correlated (r=-0.35 to -0.74). A random-effects mixed model demonstrated a significant (P=0.0019) negative association between threshold current and blood lead concentration. The data of this study demonstrate that lead exposure enhances predatory aggression in the cat and provide experimental support for a causal relationship between lead exposure and aggressive behavior in humans.

Aggression↗

PubMed2002

Lead in breast milk and maternal bone turnover.

OBJECTIVE: Our purpose was to determine whether breast milk lead (Pb) levels are correlated with maternal blood Pb levels, bone loss, or bone turnover during reproduction. STUDY DESIGN: Data were collected prospectively at 0, 1.5, 3, 6, and 12 months after delivery in 15 lactating and 30 bottle-feeding women. Variables included breast milk Pb (inductively coupled mass spectrometry), maternal blood Pb (atomic absorption spectrophotometry), osteocalcin (radioimmunoassay), and bone mineral density change (dual-energy x-ray absorptiometry). RESULTS: Mean Pb breast milk concentrations were 6.1, 5.6, 5.9, and 4.3 ng/mL at the 1.5, 3, 6, and 12 months post partum, whereas mean maternal blood Pb concentrations were 1.4, 1.6, 1.7, and 1.4 microg/dL at 0, 3, 6, and 12 months post partum. The 5.6% bone loss and significant bone turnover were related to breast milk Pb levels but not to postpartum maternal blood Pb levels. Maternal and breast milk Pb values were modestly correlated at 1 to 2 months. CONCLUSIONS: Bone loss and bone turnover were related to breast milk Pb levels. In these women, there was no evidence that either high maternal blood or breast milk Pb concentrations are a major public health concern.

Adult↗

PubMedDate not supplied

Blood lead concentrations and pregnancy outcomes.

In this study, the authors related blood lead concentrations to Apgar scores, birth weight, gestational age, small-for-gestational age, and hypertension in pregnancy (HIP)/toxemia. Data and blood were collected 4 times during pregnancy from 705 women, aged 12-34 yr. Blood lead concentrations, measured by atomic absorption spectrophotometry, were related to reproductive outcomes, abstracted from medical records. Average blood lead concentrations were 1.2 microgram/dl (standard error = +/- 0.03). Maternal blood lead concentrations were related significantly to HIP/toxemia--before and after adjusting for age, calcium intake, and race/ethnicity (p < .03). Longitudinal regression analyses revealed that blood lead concentrations in women with HIP/toxemia changed by 0.02 microgram/dl for every 0.01 microgram/dl change in women without HIP/toxemia. Maternal blood lead concentration and its change were not significantly associated with other reproductive outcomes. Low levels of maternal blood lead concentrations were significantly associated with HIP/toxemia.

Adolescent↗