Biomedical subjects

D S Arce

Publications and source records attributed to D S Arce.

3 recordsLinked to original sources

PubMed1993

Effects of marginal and severe iron deficiency on hepatic proteins in developing rats are reversible with dietary iron repletion.

Transferrin, metallothionein, cytochrome P-450, and the in vitro formation of DNA-benzo[a]pyrene adducts were studied in the offspring of dams that were fed diets moderately or severely deficient in iron (Fe). The study was designed to determine whether Fe deficiency-induced alterations were reversible or if they persisted with post-weaning iron repletion. Throughout gestation and lactation the dams were fed a Control diet = 120 micrograms Fe/g diet, a Marginal Iron diet = 11 micrograms Fe/g diet, or a Low Iron diet = 7 micrograms Fe/g diet. On day 14 of lactation, 4 pups per litter were killed. On day 21, the dams were killed. Half of the remaining pups in each litter were fed their respective diets until they were killed on day 42 (Marginal Iron-Marginal Iron and Low Iron-Low Iron groups). The other half were fed the Control diet (Marginal Iron-Control and Low Iron-Control groups). The dietary intake of the Restricted Fed offspring was matched to rats in the Low Iron-Low Iron group. Offspring in the iron-deficient groups had hematocrits, hemoglobin concentrations, and liver iron levels that were lower than Controls. Day 42 offspring in the iron-deficiency groups had a lower food intake and higher liver zinc and copper levels than Controls. Day 14 Marginal and Low Iron pups had liver metallothionein levels that were lower than Controls. Day 42 Restricted Fed offspring had liver metallothionein levels that were higher than all other groups. Cytochrome P-450 levels and the in vitro formation of benzo[a]pyrene-DNA adducts were higher in Low Iron-Low Iron males than in Control males. Ethoxycoumarin O-deethylase activity was higher in day 42 Low Iron-Low Iron offspring than in Controls. These results show that the iron deficiency-induced alterations were transient, reversible with iron repletion, and in the case of cytochrome P-450 and ethoxycoumarin O-deethylase activity, dependent on the age and sex of the animal.

7-Alkoxycoumarin O-Dealkylase↗

PubMed1992

Reversible and persistent consequences of copper deficiency in developing mice.

The effect of maternal copper (Cu) deficiency on various proteins was studied to determine if the changes were reversible or persistent with Cu repletion. The functional consequences of these alterations were assessed by exposing the animals to an oxidative stress (endotoxin), and by measuring the formation of benzo[a]pyrene-DNA adducts in vitro. Throughout gestation and lactation, mice were fed a Control diet (10 micrograms Cu/g diet) or a Low Cu diet (1 microgram Cu/g diet). On day 18, the offspring were killed or switched to the Control diet and killed on day 42 following a single injection of saline or endotoxin on day 41. In day-18 offspring, Cu deficiency resulted in decreased hematocrit values, ceruloplasmin activity, liver and tissue Cu levels, and metallothionein concentrations. Cu repletion restored all but metallothionein levels. Early Cu deficiency led to higher brain CuZn superoxide dismutase activity on day 42, and higher levels of brain thiobarbituric acid reactive substances (TBARS) in endotoxin-treated mice. Liver TBARS were lower in day-18 Low Cu offspring and in day-42 Low Cu offspring treated with endotoxin than age-matched Controls. Cytochrome P-450 concentrations were lower in Low Cu, endotoxin-treated males than in Controls. These results show that Cu deficiency-mediated alterations during early development are not immediately reversed with Cu repletion.

7-Alkoxycoumarin O-Dealkylase↗

PubMed1986

Volatile fatty acids: their production, absorption, utilization, and roles in human health.

The evidence shows that microbial fermentation of carbohydrates and endogenous substrates occurs in the large intestine of humans and that VFA represent a major endproduct. The large number of bacterial species, the complex nature of their interactions, and the endproducts of their fermentation processes are all likely to have significance in human health. Fermentation in the human intestine resembles rumen fermentation with respect to the metabolic pathways involved in anaerobic degradation of organic matter and in the concentrations of VFA endproducts. Thus, rumen bacteria are useful for understanding the dynamics and potential interactions of human intestinal bacteria. Current research is directed towards examining fermentation processes in animals, such as the pig and some species of monkey, since these animals most closely resemble the human. From such animal studies the metabolic activities of VFA and the processes by which they are produced and absorbed can be more clearly investigated and understood. The effects of diet on the microflora and on the metabolic pathways leading to the generation of VFA are under investigation. Modification of diet seems the most likely way of modifying the extent to which VFA are produced and absorbed by the human. As methodologies and protocols for evaluating human intestinal fermentation in vivo are revised and made more sensitive, the significance of fermentation will become more clearly understood. However, it appears that VFA make a physiologically significant contribution to the health of the colonic mucosa, and to the energy supply of the host. The magnitude of these effects is probably influenced by diet.

Animals↗