Cadmium toxicity decreased by dietary ascorbic acid supplements.

Feeding the environmental toxicant cadmium to young Japanese quail for 4 weeks produced growth retardation, severe anemia, low concentrations of iron in the liver, and high concentrations of cadmium in the liver. Dietary ascorbic acid supplements almost completely prevented the anemia and improved the growth rate but did not markedly alter concentrations of iron or cadmium in the liver.

Calcium carbonate concretions: cyclic occurrence in the hamster vagina.

Three crystalline forms of calcium carbonate were identified in washings of the hamster vagina. Spherical concretions of vaterite and hexagonal concretions of calcite predominate on days 3 and 4 of the 4-day estrous cycle. Dumbbell-like concretions of aragonite predominate during pregnancy and pseudopregnancy. Each polymorph is associated with an acid-insoluble matrix. Concretions disappear after ovariectomy and reappear during daily injections of estrogen and progesterone.

Elemental content of predigested liquid protein products.

Eight commercially available partially digested gelatin liquid products that have been used as a source of protein in dietary regimens for weight reduction and for protein supplementation were analyzed for their elemental composition. These products were prepared either by dry ashing or wet digestion techniques that were suitable for the analysis of individual elements by their respective analytical methods. Analytical methods used to assess the elemental content included inductively coupled argon plasma emission spectrometry for Ca, Mg, P, Fe, Zn, Cu, Mn, Ni, Mo, V, Be, Co, Cr, Tl, Al, Te, Sn and Sb; atomic absorption spectrophotometry for Na and K; hybride generation with atomic absorption spectrophotometry for Se and As; anodic stripping voltammetry for Cd and Pb; and ion selective electrode for F. The content of almost all of the elements in these products was extremely low compared with the amounts supplied daily for normal individuals by usual sources of dietary protein, the adult United States Recommended Daily Allowances, and typical intakes from the Total Diet Study. The following elements were not detectable in significant amounts in these products by inductively coupled argon plasma emission spectrometry: Mo, V, Be, Co, Cr, Tl, Al, Te, Sn, and Sb. The results suggest that use of these predigested liquid protein products as a sole source of nutriment will result in an inadequate intake of all of the essential elements. These products contained insignificant amounts of Ce and Pb, nonessential toxic elements.

Effects of zinc, iron and copper deficiencies on cadmium in tissues of Japanese quail.

Experiments with young Japanese quail were conducted to determine whether combined moderate deficiencies of zinc, iron and copper would cause greater uptake and tissue retention of cadmium than the single deficiencies. Birds were fed the experimental diets containing 62 ppb cadmium from hatching to 16 days of age. On day 9 each bird received a dose of 109CdCl2 in its diet. On day 10, the duodenal and jejunal-ileal tissues contained large amounts of cadmium, and there were many significant effects of treatment on cadmium-109 retention in the livers and kidneys. At day 16, zinc deficiency caused increased cadmium in the liver, whereas iron and copper deficiencies each caused increased cadmium in the kidneys. Combined deficiencies had little or no greater effect than single deficiencies and in some cases the combined effect was less than that of a single deficiency.

Effects of nutritional factors on metabolism of dietary cadmium at levels similar to those of man.

Several nutrients are known to affect cadmium toxicity, but little is known about the effect of dietary nutrient levels on absorption and tissue retention of cadmium at low dietary levels, similar to those of man. Feeding gradedlevels of zinc in a casein-gelatin diet to young Japanese quail with 109Cd (as the chloride) and 0.062 ppm added cadmium decreased the cadmium concentrations in the proventriculus-ventriculus, duodenum, jejunum-ileum, and the liver, but not in the kidney. Zinc also affected some zinc, iron, manganese, and copper tissue levels. Different tissue concentration patterns of cadmium and essential minerals were obtained with two purified control diets, one based on casein-gelatin and the other on soy isolate as the principal protein sources. The data show that relatively small dietary changes can markedly affect tissue levels of cadmium and that a low intake of zinc may increase the risk to dietary cadmium exposure. The complexity of the nutrient interrelationships and their effects on cadmium require further study to define mechanisms, which may be similar to those produced by low cadmium intakes in man.

Effects of vitamin C and iron and cadmium metabolism.

Toxic levels of dietary cadmium (5-200 ppm) interfered with iron absorption and produced an iron deficiency. Supplements of iron (particularly the divalent form) and ascorbic acid protected against the cadmium. With very low levels of dietary cadmium (about 0.06-0.08 ppm), typical of those in the diets of humans, supplements of iron(II) and ascorbic acid markedly decreased cadmium concentrations in the liver, kidney, and small intestine. Iron deficiency changed the distribution of cadmium within the body. The effect of ascorbic acid on cadmium metabolism appears to depend primarily, if not entirely, on its influence in improving iron absorption. Maintenance of modest iron stores appears to be very important in minimizing cadmium absorption.

Magnesium deficiency, requirement and toxicity in the young Japanese quail.

Studies of magnesium deficiency, requirement and toxicity in the young Japanese quail (Coturnix coturnix japonica) were conducted. Day-old birds were fed an adequate purified diet containing 35% soy protein to 2 weeks of age. Residual magnesium in the diet without any added magnesium salts was 21 p.p.m. magnesium was supplied by graded amounts of MgSO4 to a total of 11 levels ranging from 125 to 2,000 p.p.m. Deficiency signs included poor growth, and occasionally excitability, gasping and convulsions. Most mortality occurred during the first 7 days. The maximum dietary magnesium concentrations that produced the minimal significant deviation from normal values for mortality, body weight, hemoglobin and tibia ash was 225, 200, 250 and 250 p.p.m., respectively. Based on these measurements, 300 p.p.m. magnesium is considered adequate to meet the young quail's requirement under the conditions of these experiments. With 2,000 p.p.m. magnesium, the only adverse effect was an increase in mortality. Between 200 and 1,000 p.p.m. magnesium there was a linear relationship between concentration of magnesium in the tibia and the log of the concentration of dietary magnesium. This suggests that tibia magnesium concentration might be useful for bioassay of magnesium in foodstuffs.

Magnesium stores and anemia in young Japanese quail.

Studies were conducted to determine the effect of age on magnesium requirement and whether high dietary magnesium during the first 7 days of life would protect against subsequent magnesium deficiency. Day-old Japanese quail were fed a casein-gelatin diet containing either 300 (requirement) or 600 ppm Mg. Beginning on day 7, half of the birds in each group received either 160 (deficient) or 300 ppm Mg. In birds fed the requirement level during week 1 followed by the deficient diet, hemoglobin decreased on day 10, reaching the lowest value on day 14. Other adverse effects included mortality; slightly reduced growth rate; elevated iron in the liver, spleen, and tibia; decreased tibia magnesium; and increased spleen weight. Higher dietary magnesium (600 ppm) during week 1 prevented deficiency when 160 ppm Mg was fed in week 2; however, tibia magnesium was lower than that in birds fed 300 ppm Mg throughout. The protection may be related to reutilization of skeletal magnesium, which was elevated on day 7. In this and another experiment, birds initially fed 300 ppm Mg followed by 160 ppm (7-28 days) or 125 ppm Mg (14-28 days) had normal hemoglobin values at 21 and 28 days. These experiments showed that magnesium requirement decreased as quail aged (up to 4 weeks) and that a high magnesium diet (600 ppm) fed through days 0-7 protected against subsequent dietary inadequacy.

Protection against zinc deficiency by prior excess dietary zinc in young Japanese quail.

Three experiments were designed to determine whether an excess of zinc during the first week of life would afford any protection to young Japanese quail during a subsequent period of zinc deprivation. Day-old birds of both sexes were fed an adequate purified diet containing soybean protein with requirement (25-30 mg/kg of diet) or higher levels of zinc for 1 week. The zinc level was reduced during the second week to the deficient level of 1mg/kg of diet, except for the controls which continued to receive an adequate or higher level of zinc (25, 30 or 75 mg/kg of diet). With this low zinc intake, birds that received an initial level of zinc in excess of requirement grew significantly better (body weight and length of primary wing feathers) than those that initially received the required amount of zinc. Data on zinc content of liver, breast muscle, tibia and whole body retention suggest that bone may store zinc consumed in excess of requirement and that this zinc may be available for utilization during a subsequent period of zinc deprivation in a growing animal that has rapidly remodeling bones.

Enhancement of acute myocardial lesions by asthma drugs in rats.

Asthma morbidity and mortality have risen significantly in the last 10 years. The reasons for the increase are multifactorial. One proposed explanation is possible myocardial toxicity arising from the use of beta-agonists alone or in combination with methylxanthines. Previous studies have shown that beta-agonists given alone and beta-agonist/methylxanthine combinations given at higher than recommended clinical doses induced dose-related cardiotoxicity and sudden death in rats. The objective of the present study was to determine whether or not beta-agonists given alone and in combination with methylxanthines at recommended clinical doses also induce cardiotoxicity and sudden death in rats. The beta-agonists, isoproterenol hydrochloride (15 micrograms/kg), fenoterol hydrobromide (40 micrograms/kg), and terbutaline hemisulfate (0.4 mg/kg) were given in single sc doses separately and concurrently with the methylxanthines aminophylline hydrate (20 mg/kg) and caffeine (40 mg/kg), which were given up to a susceptible animal model, the heavy Sprague-Dawley rat. beta-agonist-induced myocardial toxicity (necrosis) was observed. The toxicity was enhanced by aminophylline resulting in the sudden death (most likely due to ventricular fibrillation) of some animals. A decrease in serum iron levels was observed in rats of all beta-agonist and/or methylxanthine-treated groups.