Donald E. Hill

The role of maternal diet in the developmental toxicology of ethanol

A commonly observed result of ethanol administration to experimental animals is a reduction in voluntary dietary intake. The purpose of this investigation was to examine the role of this reduction in the developmental/reproductive toxicity of ethanol. To achieve this objective, female C3H mice were administered one of the following diets from Day 0 to Day 17 of pregnancy: (1) liquid diet, (2) liquid diet plus 4.1% w/v ethanol, (3) an amount of liquid diet equal to that consumed by the liquid diet plus 4.1% w/v ethanol group, i.e., pair-fed, (4) liquid diet fortified with protein, fats, carbohydrates, vitamins, and minerals, or (5) fortified diet plus 4.1% w/v ethanol. An important aspect of this experiment was the 2 X 2 factorial design, which permitted the analysis of the effects of ethanol consumption, diet intake reduction, and potential interactions between these two factors. After maternal death on Day 17 of gestation, fetuses were examined for evidence of alterations in growth and/or development. Analysis of the results revealed that decreased dietary intake, but not ethanol consumption resulted in a decrease in fertility, maternal pregnancy weight gain, and litter size. In contrast, both decreased dietary intake and ethanol consumption significantly inhibited fetal growth and development. However, no interaction between these two factors was demonstrated, indicating that ethanols fetotoxic effects occurred, regardless of maternal dietary intake. We conclude that, depending on the endpoint examined, maternal nutrition plays a key role in experimental ethanol fetotoxicity. However, this agent is fetotoxic, even in the well-nourished animal.

Maternal, fetal, and neonatal elimination of ethanol in nonhuman primates

Three cynomolgus and 6 rhesus monkeys (106-160 days gestational age) were administered ethanol (0.8-1.5 g/kg i.v.) over a 30-min period. Blood samples were drawn under anesthesia from catheters in the maternal femoral artery, fetal umbilical circulation and/or neonatal umbilical artery. Comparison of maternal/fetal blood sample pairs from 60 to 300 min after initiation of the ethanol infusion revealed a significant correlation of blood ethanol concentration (r = 0.968, p less than 0.001). Thus, during the elimination phase, maternal blood ethanol concentrations are predictive of fetal blood ethanol concentrations. In three studies where the fetus was delivered 2 h after the infusion of ethanol, the neonatal rates of elimination were observed to be approximately 1/4 those of the mother. These data indicate that during the last third of nonhuman primate pregnancy, the maternal component of ethanol elimination appears to be the predominant factor in the overall rate of fetal ethanol elimination.

Comparison of the metabolism of cortisol and triamcinolone acetonide in the early, mid, and late gestational age rhesus monkey (Macaca mulatta)

The metabolism of radiolabeled cortisol and triamcinolone acetonide (TAC) was compared in the early, middle, and late gestational age rhesus monkeys. Trace amounts of 14C-cortisol and 10 mg/kg 3H-TAC (Kenalog) were simultaneously administered i.m. to the maternal animal. Whole 30-day embryos or 61- to 137-day fetal organs, amniotic fluid, and placenta were collected from 0.5 to 24 h after dose administration and analyzed by high-performance liquid chromatography (HPLC). Serial blood samples collected from all maternal animals and the late gestational age fetuses were similarly processed. The maternal plasma concentration of total radioactivity derived from TAC 1-60 min after dose administration was significantly less on day 30 of gestation as compared to day 60 at the 5-, 10-, and 60-min time points. At 60 and 130 days of gestation, however, the maternal plasma concentrations of total radioactivity were similar. Concentrations of cortisol-derived radioactivity in the maternal plasma were the same across gestational age. The plasma TAC and cortisol metabolic profiles, as determined by HPLC, were not significantly different throughout pregnancy. In late pregnancy 30 min after dose administration, the fetal to maternal plasma cortisol ratio was 0.34, whereas the same ratio for TAC was 0.96. By 1 h after dose administration, less than 8% of the total 14C radioactivity in fetal tissues was cortisol and over 92% of the 3H was TAC. The extensive fetoplacental metabolism of cortisol to inactive metabolites and the resistance of TAC to metabolic conversion results in greater TAC than cortisol exposure of the developing rhesus monkey conceptus.

Functional bacterial opsonic activity of human amniotic fluid

There are some data to suggest that amniotic fluid protects the fetus from invasion by pathogenic bacteria. To examine methods by which amniotic fluid may offer such protection, quantitative antibody, complement activity, and functional opsonic capacity were measured. Immunoglobulins were measured by laser nephelometry and total hemolytic complement was determined by radial diffusion; results suggested activity adequate for bactericidal capacity. The chemiluminescence assay was used to quantitate the functional interaction between polymorphonuclear leukocytes and E. coli, group B streptococci (GBS), or zymosan particles preopsonized with amniotic fluid obtained at different stages of gestation. Results were compared to those for normal serum. Data were analyzed by evaluation of the initial slope, area under the curve, and peak chemiluminescence response. Opsonic activity of amniotic fluid for E. coli and GBS was demonstrated, with E. coli showing greater reactivity (maximum = 15,000 to 25,000 cpm) than GBS (10,000 to 20,000 cpm). Specific, as well as nonspecific, opsonic activity was demonstrated by absorption of amniotic fluid with killed bacteria. Concentration of amniotic fluid did not result in an increase in chemiluminescent activity, which demonstrates that optimal opsonic activity already exists. The classical and alternate pathways of complement were assessed for E. coli and GBS. Preterm amniotic fluid did not differ in response from that of amniotic fluid obtained from term pregnancies. This study demonstrates that amniotic fluid can provide the fetus with protection from bacterial pathogens and delineates mechanisms for such protection.

Clinical Correlates in Nutritional Disease

Many of the nutritional disorders of infants and children such as rickets, scurvey, marasmus and kwashiorkor have been recognized by their clinical and laboratory findings. Less well appreciated are the abnormalities in growth due to major disturbances in macronutrient intake, absorption and/or utilization that result in failure-to-thrive at one end of the spectrum or obesity at the other end. The origins of these growth abnormalities related to nutrition are frequently manifest in-utero or in infancy and may be corrected by appropriate diagnosis and intervention. The purpose of this article is to highlight some clinical examples of failure-to-thrive and to contrast these with excessive growth and obesity.