Search PubMed⌕ Search

Biomedical subjects

T F Collins

Publications and source records attributed to T F Collins.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effect of ethanol and vitamin A excess on vitamin A status in the liver, plasma and foetuses of pregnant rats.

The effect of maternal consumption of dietary ethanol and high doses of vitamin A by gavage was investigated by evaluating plasma, liver and foetal vitamin A in Osborne-Mendel pregnant rats with a view to assessing whether ethanol modulated the potential toxicity of excess vitamin A. All groups received 4000 IU vitamin A/litre in a liquid diet. Ethanol-exposed groups also received 6.4% (v/v) ethanol in the liquid diet. Vitamin A was administered by gavage once per day in corn oil in doses ranging from 10,000 to 160,000 IU/kg body weight. Plasma vitamin A levels in ethanol-exposed groups were similar to levels in a pair-fed group. Plasma vitamin A levels were similar in the group given ethanol plus 40,000 IU vitamin A/kg and the group given 40,000 IU vitamin A/kg only, but were higher in the group receiving ethanol plus 80,000 IU vitamin A/kg than in the group given 80,000 IU vitamin A/kg only. Retinyl esters were present in the plasma of animals receiving 160,000 IU vitamin A/kg only, indicating possible saturation of the liver with vitamin A. Retinyl palmitate levels in female foetuses of the group administered ethanol plus 80,000 IU vitamin A/kg were significantly higher than those of the group administered 80,000 IU vitamin A/kg only; no significant differences in levels of retinyl palmitate in male foetuses were observed between these two groups. This observation suggests a possible sex difference in the modulation of vitamin A toxicity by ethanol in the foetus.

Administration, Oral↗
PubMed1994

Mineral interactions in rats fed AIN-76A diets with excess calcium.

The effects of moderate increases in dietary calcium on maternal and foetal mineral interactions were studied in Charles River CD/VAF Plus rats. Female rats were given 0.50, 0.75, 1.00 or 1.25% dietary calcium as calcium carbonate in AIN-76A diets for 6 wk before mating, during mating and for 20 days of gestation. Inductively coupled argon plasma-atomic emission spectrometry was used to determine mineral levels in the tissues of non-pregnant rats after 42 days on the diets, in the tissues of pregnant rats on day 20 of gestation and in the whole body of day-20 foetuses. The femurs of the non-pregnant and pregnant rats had a dose-related linear increase in calcium content. In livers of the non-pregnant rats, dose-related linear increases in the phosphorus, zinc and magnesium content were observed, but there was a dose-related decrease in the iron content. There were dose-related linear decreases in the iron and copper contents of the kidneys from the non-pregnant rats. In pregnant rats dose-related linear decreases were observed in the iron content of the liver and in the zinc, iron and magnesium contents of the kidney. The foetuses from rats given a moderate increase in dietary calcium had dose-related decreases in the whole-body contents of phosphorus, iron, copper and magnesium.

Animals↗
PubMed1993

Foetal development in rats fed AIN-76A diets supplemented with excess calcium.

This study was designed to evaluate the developmental effects of moderate dietary calcium increases in rats fed nutritionally adequate diets. Female Charles River CD/VAF Plus rats were given 0.50 (control), 0.75, 1.00 or 1.25% dietary calcium as calcium carbonate in AIN-76A diets for 6 wk before mating, during mating and for 20 days of gestation. On gestation day 20, the animals were killed and caesarean sections were performed. Both the non-pregnant and pregnant rats in the 0.75, 1.00 and 1.25% groups ate slightly more than did the control group during most of the intervals measured, but not all the increases were statistically significant. There was no consistent pattern of increase or decrease in weight gain. No dose-related changes were found in maternal clinical findings, the average number of implantations, resorptions and viable foetuses, or foetal length or weight. Under the conditions of the study, there were no statistically significant increases as compared with the control group in the litter incidence regarding specific external, visceral or skeletal variations of the foetuses. Dietary calcium was neither foetotoxic nor teratogenic at the concentrations used.

Analysis of Variance↗
PubMed1993

Teratogenic potential of FD & C red no. 3 when given in drinking water.

FD & C Red No. 3 (erythrosine), a commonly used food additive, was administered to pregnant Osborne-Mendel rats to study its teratogenic potential. Dosing solutions of 0.05, 0.1, 0.2 or 0.4% in distilled water were available at all times and corresponded to daily doses of 64, 121, 248 and 472 mg FD & C Red No. 3/kg body weight. Distilled water served as the control. On gestation day 20, the animals were killed and caesarean sections were performed. The treated animals consumed less fluid than did the control animals, but only random decreases were statistically significant and no dose relationship was seen. Only the 0.2% group consumed significantly more feed than the controls during gestation. Maternal weight gain during days 0-20 was not significantly affected in any group. No dose-related changes were seen in maternal clinical findings, implantations, foetal viability, foetal size (weight and length) or visceral development. No dose-related teratogenesis was seen. Skeletal development was not affected; the few statistically significant increases in skeletal variations were not dose related and were considered to be random. FD & C Red No. 3 was neither foetotoxic nor teratogenic at the dose levels tested in drinking water.

Administration, Oral↗
PubMed1992

Study of the teratogenic potential of FD & C yellow No. 5 when given in drinking-water.

FD & C Yellow No. 5 was available to pregnant Osborne-Mendel rats throughout gestation at dose levels of 0.05, 0.1, 0.2, 0.4 or 0.7% in solution in distilled drinking-water. Based on fluid consumption, the rats received 67.4, 131.8, 292.4, 567.9 and 1064.3 mg FD & C Yellow No. 5/kg body weight/day. Distilled water served as the control. No dose-related changes were seen in mean daily food consumption or maternal body-weight gain. Starting during the second trimester of gestation, fluid consumption was significantly greater in the rats given 0.7% FD & C Yellow No. 5 than in the controls. The females were killed on gestation day 20. No dose-related changes were seen in maternal clinical findings, implantations, foetal viability or foetal size (weight and length). No dose-related foetal terata were seen. Neither visceral development nor skeletal development (sternebral and other skeletal bones) was affected by the dye. The small numbers of statistically significant increases in skeletal variations in the 0.05 and 0.4% levels are considered random because they are not dose related.

Abnormalities, Drug-Induced↗
PubMed1990

Developmental effects and mineral interactions in rats fed textured vegetable protein.

The teratogenic effects of feeding a diet based on textured vegetable protein to Long-Evans rats were studied along with maternal and fetal mineral interactions and their relationship to diet composition. Pregnant rats were fed purified diets containing 18% protein as casein (CAS), textured vegetable protein (TVP, from defatted soy flour) with 18 mg Zn/kg, or TVP diet with 100 mg Zn/kg. A fourth group was fed diet NIH-31. The animals received their diets throughout pregnancy and were sacrificed on day 20 of gestation. Fetuses were examined for developmental effects, and mineral levels were determined in maternal and fetal tissues by inductively coupled argon plasma-atomic emission spectrometry. Females fed the casein diet or diet NIH-31 had normal weight gains throughout pregnancy and their progeny exhibited normal development. The animals on the TVP-containing diet with 18 mg Zn/kg had decreased food consumption and body weights, and their fetuses exhibited developmental anomalies as well as reductions in size and weight. These developmental alterations may be the result of decreased zinc levels in the fetal tissues, caused by reduced bioavailability of the trace element in the maternal diet. Significant increases in tissue iron accompanied the low zinc levels. No developmental effects were found in animals receiving the high Zn-TVP diet, and mineral data from these animals were not significantly different from the casein group.

Animals↗
PubMed1990

Study of the teratogenic potential of FD & C Yellow No. 5 when given by gavage to rats.

FD & C Yellow No. 5 (tartrazine) was given to Osborne-Mendel rats by gavage at dose levels of 0, 60, 100, 200, 400, 600 or 1000 mg/kg body weight/day on days 0-19 of gestation. No maternal or developmental toxicity was observed when the rats were killed on day 20. The mean daily food consumption for the entire period of gestation was significantly greater in the females given 1000 mg/kg body weight/day than in the controls, but maternal body-weight gain was not affected. No dose-related effects were observed in implantations, foetal viability or external foetal development. Foetal skeletal and visceral development was similar among foetuses from all groups. At the doses given, FD & C Yellow No. 5 was neither toxic nor teratogenic.

Abnormalities, Drug-Induced↗
PubMed1990

Mutagenicity, metabolism, and DNA interactions of urethane.

Urethane, a known animal carcinogen, has been the subject of intensive research efforts spanning 40 years. Recent concerns have focused on the presence of urethane in a variety of fermented foods and alcoholic beverages, although no epidemiological studies or human case reports have been published. Much information is available about the mutagenesis, metabolism, and DNA interactions of urethane in experimental systems. Urethane is generally not mutagenic in bacteria although in some instances it acts as a weak mutagen. Urethane is not mutagenic in Nuerospora but is weakly mutagenic in Saccharomyces. Drosophila appear to be the only organisms that consistently give positive mutagenic results with urethane, but its mutagenicity is weak and in many cases shows no clear dose dependence. Urethane is a good clastogen in mammalian somatic cells in vivo, but it shows variable results with cells in vitro. It efficiently induces sister chromatid exchanges in a variety of cells. Mammalian spermatogenic cells are insensitive to the induction of specific locus and dominant lethal mutations by urethane. Mutational synergism has been reported to occur between ethyl methanesulfonate and urethane when administered two generations apart, and some investigators have suggested possible synergism for cancer-causing mutations in mice exposed to X-rays and urethane one generation apart. These studies are controversial and have not been confirmed. Studies on the induction of cancer-causing dominant mutations by urethane are at variance with results from extensive studies with the specific locus test in mice. Urethane studies with the unscheduled DNA synthesis assay in mouse spermatogenic cells and with the sperm abnormality test have given negative results. Urethane is rapidly and evenly distributed in the body. The rate of elimination of urethane from plasma is a saturable process and varies according to the strain and age of the animal. Recent studies have concentrations similar to those in wine, ethanol inhibits the tissue distribution of urethane in mice. These results are important because they suggest a lower carcinogenic/mutagenic risk than expected from exposure to urethane in alcoholic beverages. Although research on the metabolic activation of urethane has been extensive, no conclusive results have been obtained about its active metabolite, at one time thought to be N-hydroxyurethane. More recently, it has been postulated that urethane is activated to vinyl carbamate and that this metabolite is capable of reacting with DNA.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Study of the teratogenic potential of FD & C Red No. 40 when given by gavage to rats.

Osborne-Mendel rats were intubated with FD & C Red No. 40 at dose levels of 0, 30, 75, 150, 300, 600, or 1000 mg/kg body weight/day on days 0-19 of gestation. No developmental toxicity was observed when the animals were killed on day 20 of gestation. No dose-related changes were seen in maternal daily observations, food consumption, body-weight gain or implantations, or in foetal viability, body weight, body length, sex distribution or external variations. Skeletal and soft-tissue development appeared similar in foetuses of all groups. The isolated increases that occurred in the number of male foetuses, number of females with two or more resorptions, number of litters with three or more sternebral variations and incidence of 14th rib bud are considered random occurrences and were not related to dosage.

Administration, Oral↗
PubMed1989

Study of the teratogenic potential of FD&C Red No. 40 when given in drinking water.

FD&C Red No. 40 in the drinking water at a level of 0, 0.2, 0.4, or 0.7% was available ad libitum to female Osborne-Mendel rats throughout gestation. The treated females consumed 273.6, 545.7, and 939.3 mg FD&C Red No. 40 per kg body weight per day, respectively, for the three dose levels. The animals were sacrificed on gestation day 20. No fetal terata were seen. There were no dose-related changes in maternal findings, number of fetuses, fetal viability, or external or visceral variations. Skeletal development appeared similar to that of the control animals with the exception of the incidence of fetuses with reduced ossification of the hyoid, which was increased significantly at the 0.7% dose level. A dose-related increase occurred in the number of litters containing fetuses with at least two skeletal variations, but the numbers of litters with fetuses with at least one and at least three variations were not different from control values.

Abnormalities, Drug-Induced↗
PubMed1987

Potential reversibility of skeletal effects in rats exposed in utero to caffeine.

Groups of Osborne-Mendel rats, killed at three time intervals following mating, were studied to determine whether prenatal skeletal ossification delays observed following low-level caffeine administration represent transient or persistent ossification problems. Group A litters were killed on gestation day 20; group B neonates were killed on post-natal day 0; and group C pups were killed on post-natal day 6. Within each group, dose levels of 0, 0.018, 0.036 or 0.07% caffeine in distilled water were available ad lib. to groups of 30-60 dams from gestation day 0 to day 20. Average daily caffeine consumption was 24.7-29.0 mg/kg body weight for the 0.018% group, 42.7-48.8 mg/kg body weight for the 0.036% group and 70.6-75.1 mg/kg body weight for the 0.07% group. In group A litters, the mean number of viable foetuses was significantly less in the mid-dose and high-dose animals than in the controls. In the same group, the average number of foetuses per litter with at least one sternebral ossification delay was increased significantly in all treated groups and the average number of foetuses per litter with at least two sternebral variations was significantly increased in the mid- and high-dose groups. The percentages of litters containing foetuses with at least two and at least three sternebral variations and the average number of foetuses per litter with at least three sternebral variations were significantly increased only in the high-dose group. Foetuses from the mid- and high-dose groups also had significant increases in certain skeletal defects, namely missing centra and reduced ossification of the dorsal arch. Foetuses from the high-dose group also had significant increases in bipartite supraoccipital, and reduced ossification of the hyoid, metacarpals and metatarsals. In group B, day 0 neonates from all treated groups showed a significantly increased incidence of delayed sternebral ossification (average number of foetuses per litter with one or more missing, incomplete or bipartite sternebrae). The percentages of litters containing neonates with delayed sternebral ossification were also increased significantly in all treated groups. Neonates from the 0.07% level in group B also exhibited a significant increase in the incidence of supernumerary rib bud, and in reduced ossification of the metacarpals, metatarsals and calcaneus bones. Significant increases were also seen, in group B, in the low- and mid-dose animals, respectively, in supernumery rib bud and in reduced ossification of the metatarsals.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormalities, Drug-Induced↗