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Biomedical subjects

E S Halas

Publications and source records attributed to E S Halas.

At least 19 recordsLinked to original sources
PubMed1991

The effects of dietary copper deficiency and psychological stress on blood pressure in rats.

In each of two experiments, adult, male Sprague-Dawley rats were deprived of copper and were subjected to the chronic stress of close confinement. A 2 X 2 factorial design was used because both copper deficiency and stress have been implicated in the regulation of blood pressure and are implicated in a major consequence of human hypertension--ischemic heart disease. Copper deficiency was verified by a decrease in copper in several organs. Both copper deficiency and stress increased blood pressure; results were independent. Sodium in heart was increased by deficiency in both experiments, but was increased in brain in only the second experiment. The combination of stress and deficiency produced an increase in mortality in one of two experiments. A decrease in cholesterol in plasma due to stress is consistent with earlier data from rats but is in contrast to data from humans. Both stress and copper deficiency produce potentially adverse changes in cardiovascular physiology and the chemistry of brain, heart and other organs. These results may be germane to humans because stress is frequent and some diets are low in copper.

Animals↗
PubMed1988

Long-term effects of lactational zinc deficiency on bone mineral composition in rats fed a commercially modified Luecke diet.

The purpose of this study was threefold: 1. to determine the long-term effects of interactions between lactational zinc deficiency and gender on bone mineral composition in repleted rat offspring, 2. to determine the nutritional efficacy of the second of two commercially designed, modified Luecke diets (ML2) during the gestational and lactational stress, and 3. determine the ultratrace element contents of Ralston Rodent Laboratory Chow #5001. The ML2 basal diet, based on dextrose, sprayed egg white, and corn oil contained 0.420 micrograms Zn/g, was supplemented with Zn (as zinc acetate) at 0 (diet 0ML2) or 30 (diet 30ML2) micrograms/g, and was mixed and pelleted commercially. All rat dams were fed the 30ML2 diet ad libitum during gestation. Beginning at parturition, the dams were fed either the 1. 0ML2, 2. 30ML2 (food restricted), or 3. 30ML2 (ad libitum) diets. All pups were fed the 30ML2 diet ad libitum from 23 to 40 d of age. From d 40 to 150, all pups were fed Ralston Rodent Laboratory Chow. The 30ML2 diet was found to be nutritionally efficacious; litter size and pup growth were normal and pup mortality was only 1.2%. Pups (ZD) with access to the 0ML2 diet until 23 d of age and nursed by dams fed the 0ML2 diet, when compared to pups (PF) fed restricted amounts of the 30ML2 diet, exhibited increased mortality and decreased concentrations of tibial zinc but no change in growth. Inadequate zinc nutriture during infancy, despite postlactational zinc repletion, induced imbalances in adult bone mineral metabolism. Thus, at 150 d of age, the ZD pups exhibited increased levels of bone P and Mg and decreased concentrations of K as compared to the PF pups.

Animal Feed↗
PubMed1987

Developmental delays in offspring of rats undernourished or zinc deprived during lactation.

Offspring of rats who were zinc or calorie deprived during lactation were administered a battery of reflex and motor tests from postnatal Day 4 to Day 21. Compared to offspring of ad lib-fed control rats, both zinc deprived and undernourished offspring exhibited developmental delays in reflexes which appeared after the first postnatal week (auditory startle, air righting, and rope descent). As the deficiencies continued the delays appeared to be more pronounced. The zinc deficiency did not add to the deficits associated with calorie restriction alone because there were no significant differences between the zinc deficient and undernourished pups on any of the measures except eye opening. When rehabilitated offspring were tested at 45 and 60 days of age for motor deficits there were no significant impairments resulting from preweaning dietary conditions. However, the growth retardation of zinc deprived and undernourished rats persisted long after dietary rehabilitation was implemented.

Animals↗
PubMed1986

Learning and memory disabilities in young adult rats from mildly zinc deficient dams.

Three experiments were conducted to test the behavior of the offspring of rat dams (ZD) fed a mildly zinc deficient diet (10.0 micrograms Zn/g) during pregnancy and lactation. Since zinc deficiency causes anorexia, a second group of rat dams (PF) was fed the same quantity of the diet during gestation and lactation as was consumed by their ZD mates. A third group of rats (AL) was fed the diet ad lib during gestation and lactation. The PF and AL dams were given zinc supplemented (25.0 micrograms Zn/ml) drinking water whereas the ZD dams were given double distilled, deionized drinking water. After weaning, the offspring of all dams were fed Purina Laboratory Chow ad lib until they were 100 days old. The offspring were then reduced to 85% of their ad lib weight and tested on a 17-arm radial maze for memory and learning. In Experiments 1 and 2, the ZD males suffered a significant learning deficit when compared to the AL males. Whereas the PF males suffered a significant learning impairment in Experiment 1, the learning deficit of the PF group was not as severe as the deficit of the ZD group. There was no impairment in reference (long-term) memory for any of the groups. In Experiment 3, significant differences in working (short-term) memory were found among the three groups of females. The ZD group was significantly inferior in working memory when compared to the PF and AL groups. No significant differences in working memory were found between the PF and AL groups.

Animals↗
PubMed1983

Learning and memory impairment in adult rats due to severe zinc deficiency during lactation.

In a series of three experiments, adult rats who suffered severe zinc deficiency and/or undernutrition during lactation were tested in a 17-arm radial maze for working memory, reference memory, forgetting and learning. In Experiment 1, eight out of 17 arms were baited. The zinc deficient (ZD) and undernourished (PF) rats revealed a learning deficit when compared to adequately nourished rats (AL). ZD rats also appeared to display a loss of working memory. No evidence of loss of reference memory was observed among any of the groups. A reverse learning procedure was used in Experiment 2 to test the same rats used in Experiment 1. ZD rats were significantly inferior in performance of the reverse learning task compared to the AL and PF rats. No significant differences in performance were noted between the AL and PF rats. Although all groups displayed forgetfulness from Experiment 1 to Experiment 2, no significant differences in forgetfulness were evidenced among the groups. In Experiment 3, all 17 arms were baited. The ZD rats displayed a significant working memory deficit as compared to the AL and PF rats. No significant differences in working memory between the AL and PF rats occurred. The possibility that the differences in performance were due to differences in food motivation or attention was considered and rejected. It was concluded that ZD rats experienced a severe learning deficit and some working memory deficit while the PF rats experienced a mild learning deficit as compared to the AL rats.

Animals↗
PubMed1982

Mild zinc deficiency and undernutrition during the prenatal and postnatal periods in rats: effects on weight, food consumption, and brain catecholamine concentrations.

Rat dams were fed a 20% sprayed egg white diet, containing 10 ppm zinc, during gestation and lactation (ZD) and compared to zinc-adequate pair-fed (PF) and ad libitum fed (AL) control animals. AL dams consumed more food than the ZD group. Throughout gestation AL dams were heavier than PF and ZD dams. During lactation AL dams were heavier than the ZD dams which in turn were heavier than PF dams. Birth weights of ZD pups were less than the PF and AL pups. Postnatal daily weight gains of ZD pups were less than the PF pups which were less than AL pups. After weaning ZD pups fed commercial rat food gained less weight than PF and AL pups, and weight gain of PF and AL pups was similar. ZD dams had lower plasma zinc than control dams at parturition and at the end of lactation. Femur zinc of ZD, PF and AL dams was similar at parturition. ZD dams had lower femur zinc than PF and AL dams after lactation. Femur and liver zinc of ZD pups was lower than in PF and AL pups at birth. Regional brain catecholamine levels were not measured, but whole brain concentrations of catecholamines were not different among the groups. Thus, while mild zinc deficiency adversely affected growth of pups, effects on brain remain to be identified.

Animals↗
PubMed1980

Malnutrition and behavior: the performance versus learning problem revisited.

At 100 days of age rats, whose dams suffered severe zinc deficiency and/or undernutrition throughout lactation, were tested in two learning tasks. One test was an original discrimination learning task and the other test was a more difficult reverse discrimination learning task. In the reverse learning test, performance differed significantly between rehabilitated malnourished rats and normal rats. Difference in motivation, and not learning ability, was the explanation for the differences in performance between the malnourished and normal rats.

Animals↗
PubMed1977

Intra-uterine nutrition and its effects on aggression.

Prenatal zinc deficiency and prenatal undernutrition were found to have adverse effects on the food consumption and weight gain of pregnant dams and their offspring. Pups whose dams suffered prenatal zinc deficiency (ZD) consumed less food and gained less weight than pups whose dams suffered prenatal undernutrition (PF). The PF pups consumed less food and gained less weight than pups whose dams were normally fed (AL). The ZD females at age 75 days were significantly more aggressive than the PF females, while the PF females were more aggressive than the AL females. At age 105 days, ZD females were significantly more aggressive than the PF and AL females. There were no differences in aggression between the PF and AL females at 105 days. Among the ZD, PF, and AL male offspring, there were no differences in aggression at either age level except that the 75 day old PF males were significantly less aggressive than the AL males. Thus prenatal malnutrition, especially zinc deficiency, seems to have differential effects on the aggressive tendencies of female and male offspring.

Age Factors↗
PubMed1975

Some effects of prenatal zinc deficiency on behavior of the adult rat.

The effect of zinc deficiency during the latter third of gestation on avoidance conditioning of young adult male rats was compared with the effect of intrauterine starvation and normal pregnancy. Animals which had experienced zinc deficiency avoided shock less well than the offspring of pair-fed control dams. The offspring of pair-fed dams avoided shock less well than animals which were the product of normal pregnancy. Response latencies were inferior in the zinc-deficient group, whereas intertrial responses were less on both the previous zinc-deficient and intrauterine starved animals.

Animals↗
PubMed1975

Zinc deficiency and brain development in the rat.

Effects of prenatal and postnatal zinc deficiency on the composition of the brain and on subsequent adult behavior were studied. Deficiency throughout the latter third of pregnancy resulted in decreased body and brain size without affecting total brain DNA, RNA, or protein. Adult males that had been subjected to intrauterine zinc deficiency displayed impaired shock avoidance. Zinc deficiency from birth until 21 days of age resulted in impaired growth, decreased brain size, diminished brain DNA, RNA and protein. Cerebellar lipid concentration was also diminished. Such male animals displayed impaired maze acquisition as adults.

Animals↗