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Biomedical subjects

R B Morrissey

Publications and source records attributed to R B Morrissey.

8 recordsLinked to original sources
PubMed1991

Chronic toxicity/carcinogenicity studies of cocoa powder in rats.

Cocoa powder (CP) was fed at levels of 0.0 (control), 1.5, 3.5 and 5.0% for 104 wk to male and female Sprague-Dawley rats derived from the F3b generation of a multigeneration study using the same CP diets. Initial methylxanthine intake was high in all treatment groups, but steadily declined until wk 26. The high dose level provided a mean methylxanthine intake of approximately 57 mg/kg body weight/day for males and 74 mg/kg body weight/day for females from wk 26 to wk 104 of the study. Compared with controls, the historical trend of methylxanthine-associated growth stimulation was evident in rats consuming diets containing 1.5% CP, while body weight was reduced in rats consuming diets containing 3.5 and 5.0% CP. Survival rates were similar in control and CP-fed rats. No evidence of treatment-related clinical disease or ocular effects was noted. An increased incidence of bilateral testicular atrophy and aspermatogenesis was present in males consuming diets containing 5.0% CP. Non-suppurative myocarditis and interstitial fibrosis of the heart were also increased in incidence in both sexes receiving diets containing 5.0% CP. The overall incidences of both pelvic dilatation and renal pelvic microcalculi were increased in most treatment groups. Although there was no difference in the incidence of benign mammary gland fibroadenomas in female rats between the control group and any CP-fed group, a marginally significant (P = 0.04) trend test was apparent. The significance of this finding is doubtful, since the incidence of this lesion in the highest dose group was well within the historical control range for this strain of rats. No evidence of carcinogenicity from dietary CP was found in either sex.

Animals↗
PubMed1990

Three-generation reproductive study of cocoa powder in rats.

Male and female Sprague-Dawley rats were continuously exposed to dietary cocoa powder at levels of 0.0, 1.5, 3.5 or 5.0% for three generations. During the initial 12-wk growth periods for the F0-, F1b- and F2b-generation rats, mean methylxanthine exposures (mg/kg/day) for males/females were 30/36, 72/86 and 104/126 for the 1.5, 3.5 and 5.0% cocoa powder groups, respectively. No consistent dose-related effects on any of the monitored reproductive indices (mating, fertility, conception, gestation, viability or lactation) were noted over three generations. Minor reductions in mean body weight relative to controls at wk 12 were observed in male rats exposed to 3.5 or 5.0% cocoa powder and female rats exposed to 5.0% cocoa powder in the F1b and F2b generations. Renal tubular mineralization in the F0-generation male rats in the 5.0% cocoa powder group was the only statistically elevated histomorphological lesion observed. Plasma cholesterol concentrations in F1b-generation rats were elevated, but cocoa powder did not affect this parameter consistently across multiple generations. Thus, continuous cocoa powder consumption by rats at levels as high as 5.0% of the diet was without effect on reproductive capacity under the conditions of a standard three-generation evaluation.

Animals↗
PubMed1984

The cariogenic potential of several snack foods.

The use of the animal model and the Konig-Hofer program-feeding machine is a valuable tool in the research effort to identify the factors contributing to dental caries. As this methodology provides uniform host, microflora, and frequency components, the food is the variable being evaluated. The relative cariogenicity of food is dependent on variations in the composition, texture, solubility, retentiveness, and ability to stimulate saliva flow. The results of these experiments indicated the equal importance of all food-related parameters on dental caries formation. If the composition of foods was solely responsible for dental caries formation, all three of the granola bars should have had similar relative cariogenicity values. This was not true. Granola bar no. 3, which was crispier in texture and less moist, had a third the relative cariogenicity value of granola bars nos. 1 and 2. As reported by other dental researchers, the production of dental caries is food related, but not simplistic in nature. Dental caries is the outcome of complicated interactions, all of which are equally important in the progress of this disease.

Animals↗
PubMed1979

Influence of whole or skim milk on cholesterol metabolism in rats.

Male Wistar rats were fed commercial ration and given whole milk, skim milk, or water to drink. After 3 weeks the control group showed the greatest weight gain. Rats given whole milk had the smallest livers. Serum cholesterol levels were significantly lower in rats fed either whole or skim milk, but other serum lipids were unaffected. Liver triglyceride levels were lowest in the rats on skim milk. Activities of hepatic fatty acid synthetase, hydroxymethyl-glutaryl coenzyme A reductase and cholesterol 7alpha-hydroxylase were similar in the two milk-fed groups and considerably lower than in the controls.

Animals↗
PubMed1979

Cholesteremia in Japanese quail: response to a mixture of vitamins C and E and choline chloride.

Five-week old, male, Japanese quail (Coturnix coturnix japonica) were given ad libitum access to glucose- soybean meal-10% fat diets containing 0, 0.25, 0.5, or 1% cholesterol, with or without the addition of a vitamin supplement (vitamin C--1 g/kg of diet, vitamin E--30 I.U./kg of diet and choline chloride--5.5 g/kg of diet). After 12 weeks, 9 quail from the 24 quail fed each diet were killed and the total cholesterol concentration of serum, liver, kidney, and aorta was determined. Cholesterol concentrations of these organs increased with increasing levels of dietary cholesterol. The vitamin supplementation enhanced the increase in the cholesterol concentration of serum and kidney, lessened the elevation of the liver cholesterol concentration and had no effect on the aorta cholesterol concentration. The remaining quail were fed the same diets, for a subsequent 12 week period, except that cholesterol was deleted. At the termination of the experiment, the total cholesterol concentration of serum, liver, and kidney returned to control level for all treatments in which organ cholesterol concentrations had been increased previously. Aortic cholesterol concentration decreased during the second 12 week period (0.5 and 1% cholesterol diets fed for the first 12 weeks), however, the aortic cholesterol concentration remained higher than those of the control at 24 weeks. No significant effect of vitamin supplementation on organ cholesterol concentration was noted at 24 weeks although serum cholesterol concentration was significantly lower for the vitamin- fed groups at all levels of dietary cholesterol. Aortic ahteromata were observed at both 12 and 24 weeks in all groups fed 0.5 and 1% cholesterol.

Animals↗
PubMed1977

Rapid accumulation of cholesterol in serum, liver and aorta of Japanese quail.

Five-week-old, male, Japanese quail (Coturnix coturnix japonica) were given ad lib. access to either a glucose-soybean meal diet with 10% fat and 1% cholesterol (inducer) diet, or a corn-soybean meal (control) diet for 10 weeks. At the beginning of the experiment, and at two week intervals thereafter, quail from each treatment were killed, and the cholesterol concentrations of serum, aorta, and liver, as well as the extent of lipid accumulation in the intima of the aortas were determined. The cholesterol concentration of the serum, aorta, and liver of the control birds remained constant throughout the experiment, while the cholesterol concentration of these organs from birds fed the inducer diet were markedly elevated. At the conclusion of the experiment, the cholesterol concentrations of the serum and liver of birds fed the inducer diet were 6.7 and 14.4 times greater, respectively, than those from the control-fed birds. Approximately 45% of the aortas from the birds fed the inducer diet exhibited moderate to severe (greater than 25% of surface area covered) lipid accumulations at 10 weeks. The rate of cholesterol accumulation appeared to be more rapid than has been reported previously for this species.

Animals↗
PubMed1977

Diet composition and cholesteremia in Japanese quail.

Male, Japanese quail (Coturnix coturnix japonica) were given ad libitum access to one of four diets: a corn-soybean meal control, control plus 1% cholesterol, a glucose-soybean meal with 10% fat plus 1% cholesterol (inducer) or inducer minus 1% cholesterol for an initial 12 weeks beginning at 22 weeks of age. Serum and liver cholesterol concentrations of quail fed the 1% cholesterol supplemented diets averaged respectively, 5.3 and 10.3 times higher than those from quail fed the corresponding diets without cholesterol. There were no significant differences in serum and liver cholesterol concentrations between groups of quail fed control diet versus inducer minus 1% cholesterol diet or between quail fed inducer diet versus control plus 1% cholesterol diet. During a second 12-week period, the quail previously fed the diets containing cholesterol were given the respective control diets. The serum and liver cholesterol concentrations returned to values comparable to those of quail fed the corresponding diets without cholesterol throughout the experiment.

Animals↗