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Biomedical subjects

T D Luckey

Publications and source records attributed to T D Luckey.

At least 37 records · Page 2Linked to original sources
PubMed1975

Studies of nutritional safety of some heavy metals in mice.

Heavy metals have been proposed as nutrient markers to allow the accurate determination of the time of passage, nutrient intake, or apparent utilization of multiple nutrients. In order to evaluate possible toxic effects of scandium, chromium, lanthanum, samarium, europium, dysprosium, terbium, thulium, and ytterbium oxides, and barium sulfate upon growth, general development, reproduction, and lactation, mice were fed different levels of these compounds for three generations. The amount of elements fed were 0,110, 100, and 1000 times the use amount. The use amounts were (in ppm2.) : Sc, 0.12; Cr, 0.02; La.0.40;; Sm. 0.80; Eu, 0.036:TB, 1.20; Dy, 1.20; Tm. 0.08; Tb, 0.12; and Ba, 0.008. The use amount was one-fifth of the concentration required for activation analysis. Mortality and morbidity were negligible. No consistent growth rate changes were observed; however, different groups showed different growth rates during different generations. The number of mice born showed no significant differences amoung treatment groups. Survival, growth rate, hematology, morphological development, maturation, reproduction, and lactational performance were comparable in mice fed the different levels of 10 heavy metal oxides to those mice fed the basal diet.

Animals↗
PubMed1975

Hormology with inorganic compounds.

Three components of the dose-response reaction, usually seen as three separate curves, are reviewed as a single continuum of the effect of the dose of any agent upon an organism. The usual considerations of any agent in toxicology are the harmful actions. The individual considerations of an essential nutrient or of a hormone usually suggests a positive action. The third component is the stimulatory action as understood in hormone research and as seen in many studies with minute doses of toxic materials. The coelescence of these concepts into one continuum gives a broad viewpoint which is helpful to understand the biologic implications of any toxic, nutritious or stimulating material under a variety of conditions. Such a view is useful in predicting results and in understanding the reaction of living organisms to their environments; when small amounts of a chemical are added to a biologic system, one parameter may be affected in one way and another parameter in the opposite manner. Consideration of the complete dose-response curve led to the concept of hormology, the sutdy of excitation. The thesis of hormology is that any harmful agent may be stimulatory for any parameter when it is administered in subharmful quantities to an organism existing in a suboptimum environment. Concepts fro hormology allow the suggestion that the zero equivalent point (zep) could be used to replace zero tolerance as a practical, legislative concept for dangerous chemicals in our environment. A reivew of three pharmacology texts revealed four types of dose-response curves. The alpha curve demonstrated a simple toxicity, the beta curve exhibited a single stimulation peak followed by a toxicity as more material was added; the gamma curve showed an initial harmful reaction followed by a stimulatory reaction which, in turn, was followed by a toxic reaction as the quantity of material administered was increased; and the delta curve was essentially a sign wave in which two peaks of stimulation were separated by a "harmful valley", then, as greater concentrations of material were administered, toxicity was noted. A brief review of agents which are stimulatory in minute doses showed that a considerable amount of work had been done with radiation and late work has established emf as a stimulatory vehicle. Little work is done with other physical agents. Organic chemical compounds are known to be stimulatory in small quantities; e.g. dietary antibiotics. The fact that antibiotics stimulate growth in germfree animals and the fact that nongermicides stimulate classic animals proves their direct effect on the animal tissues.

Animals↗
PubMed1975

Safety of heavy metals as nutritional markers.

The nutritional safety of La, Sm, Eu, Tb, Dy, Tm, Yb, Sc and Cr oxides and barium sulfate were studied in two species. The mouse study was conducted for three generations, including reproduction. During the three generations the mice were apparently not effected by quantities of metals in the feed which were 1000 times the anticipated levels. This level of metals did not exhibit any effect on the reproduction or growth of the mice through three generations. It is concluded that the metals used in the diet of the mouse at any of the use levels could be used in diets for nutritional markers. The monkey study, in which 10 times the anticipated use level of heavy metal markers were fed, further illustrates the nutritional safety of the metals studied. The tissues analyzed generally illustrated that the metals were not detectable. The balance study indicated that all the metals could be accounted for and that there is no apparent absorption of these metals.

Animals↗
PubMed1972

Isolation and characterization of a thymic factor.

A protein was isolated from bovine thymus that was shown to accelerate the appearance of hemolysin to sheep erythrocytes in neonatal mice. The isolation procedure consisted of saline homogenization, ammonium sulfate precipitation, and methanol precipitation, followed by chromatography on diethylaminoethyl-cellulose and two chromatographies on Sephadex G-150. The protein was shown to be homogeneous by polyacrylamide gel electrophoresis and by sedimentation velocity and sedimentation equilibrium analytical ultracentrifugation. The molecular weight was determined to be 79,950. Additional physical and chemical characteristics were also determined.

Amino Acids↗
PubMed1972

Markers in nutrition.

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Animal Nutritional Physiological Phenomena↗