M. R. Spivey Fox

EFFECTS OF VITAMIN C AND IRON ON 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.

Effects of Zinc Deficiency on Plasma Proteins of Young Japanese Quail

One-day-old Japanese quail were fed either a low zinc diet, the same diet supplemented with zinc, or a protein-inadequate diet containing zinc. After 4 weeks small samples of blood were collected from the wing vein of each bird after 7, 24 and 48 hours of fasting. Hematocrits and concentration of total plasma protein were determined; the plasma proteins were resolved by disc electrophoresis in poly- acrylamide gel. Birds fed the low zinc diet grew slowly and exhibited the charac teristic symptoms of zinc deficiency, whereas those receiving zinc grew and developed normally. Birds fed the protein-inadequate diet with zinc grew slowly, but appeared normal otherwise. During fasting, all birds lost weight and the total plasma proteins decreased; these effects were greatest in the zinc-deficient birds. Hematocrits were not affected by experimental treatment. The plasma protein patterns of the zinc- deficient birds were normal after 7 hours of fasting. At 24 hours, the patterns of more than one-half of these birds deviated from normal and at 48 hours the patterns of all the zinc-deficient birds were markedly changed. The plasma protein of birds receiving dietary zinc and those fed the low protein diet were normal after 7 and 24 hours of fasting. At 48 hours, minor changes were observed in a small proportion of birds in each of these groups. The data suggest a possible role of zinc in the metabo lism of one or more plasma proteins.

Effects of low levels of dietary lead and iron on hepatic RNA, protein, and minerals in young Japanese quail.

Day-old Japanese quail were fed purified diets containing either 0.2 (control), 5.4, or 16.2 ppm lead as the acetate with either 25 (deficient) or 100 ppm (adequate control) iron for 2 weeks. Iron deficiency caused decreases in hemoglobin, iron, and manganese in the liver, and hepatic RNA synthesis. Iron deficiency also caused increased concentrations of lead, calcium, and molybdenum in the liver. Lead supplements caused increased concentrations of lead in the liver, and with adequate dietary iron, each supplemental lead level caused a slight decrease in the concentration of RNA in the liver. Treatment had no effect on DNA or protein synthesis, body weight, or liver weight in relation to body weight. These low levels of dietary lead did not cause the same adverse metabolic effects observed by others with higher levels of lead; however, iron deficiency increased lead uptake by the liver and affected RNA synthesis.

Bioavailability of lead in oysters fed to young Japanese quail

Abstract The presence of lead in atmospheric particulates, soil, and seawater reflects the input of both domestic and industrial wastes. Because bivalves can concentrate large quantities of heavy metals, particularly lead, consumption of their meat may be a potential risk. The relative bioavailability of lead physiologically incorporated into oyster meat was investigated. Day-old Japanese quail were fed purified diets with three levels of lead added as either lead acetate, freeze-dried lead-dosed oyster, or lead acetate plus freeze-dried control oyster for 2 weeks. Feeding lead from any source had little or no effect on body weight, hemoglobin, hematocrit, or percentage ash in the tibia. The concentration of lead in tibia at each level of dietary lead for each type of diet was different from those for all other levels of dietary lead. Slope—ratio analysis of the data showed that lead intrinsically incorporated into oyster meat was 69–75% as bioavailable as lead in lead acetate at levels between 25 and 100 ppm dietary lead. The combinations of (1) control oyster meat with lead acetate and (2) lead acetate with copper and zinc levels equal to those in oyster meat gave responses similar to those of the lead-dosed oyster groups. Although these data showed lower bioavailability of lead in oyster meat as compared with lead acetate, the intercept of the lines at 25 ppm dietary lead suggests that the relative bioavailability may be reversed at lower levels of lead intake.

Some Effects of Cadmium on the Small Intestine

of a paper pesented at the March meeting of the Northeastern Regional Discussion Group, Stouffer’s Valley Forge Inn, King of Prussia, PA, March 22, 1974. Exposure of the lung to ozone and nitrogen dioxide leads to interesting acute and chronic injury. Brief exposure to low levels of these gases results in desquamation of epithelial cells and transitory reduction in the number of pulmonary macrophages. Inflammation of the airway, as evidenced by an influx of polymorphonuclear cells, also occurs at this stage. Very rapid regeneration of epithelial cells occurs, resulting in distinctively altered epithelial pattern, and is fairly complete by 72 hours after exposure. Macrophages also increase in number. If exposure is continued over longer periods of time, chronic changes ensure. These consist of fibrosis of the terminal airway, gross enlargement of the lung, loss of air spaces, and subtle derangement of the connective tissue fibrils. Eventually, the experimentally exposed animals possess an enlarged, inelastic lung occupying a distorted thoracic cage. Other changes will be described from slides. Pathology and Morphometry of the Equine Lung Naturally Exposed to Coal Dust Gary W. Davis, D.V.M., Ph.D., 1 Robert L. Farrell, D.V.M., Ph.D.,2 and Keiii Kiryu, D.V.M. Abstract of a paper presented at the March meeting of the Northeastern Regional Discussion Group, Stouffer’s Valley Forge Inn, King of Prussia, PA, March 22, 1974of a paper presented at the March meeting of the Northeastern Regional Discussion Group, Stouffer’s Valley Forge Inn, King of Prussia, PA, March 22, 1974 1 Ohio State University, Dept. of Veterinary Pathobiology, Columbus, OH 2 University of Georgia, Dept. of Veterinary Pathology, Athens, GA Twelve coal mine horses and ten control horses were studied for pathological changes and morphometric measurements of alveoli in the lungs. Pathologically, equine spontaneous coal mine pneumoconiosis was characterized by the following tissue responses to coal mine dust: (i) interstitial fibrosis, epithelial bronchiolar hyperplasia with muscular hypertrophy, and alveolar emphysema; (ii) silicotic nodular fibrosis and granulomatous inflammatory reaction in the regional lymph nodes of the lungs; (iii) focal granulomatous tonsilitis. Formulas were derived for the mean sectional area, surface area, and volume of the equine alveolus. In the analysis of morphometric measurements of equine alveoli, significant differences in alveolar size were demonstrated between coal mine horses and control horses. The mean diameter of the equine alveolus was determined to be one-half the mean diameter of the human alveolus as measured by Weibel. The other dimensions of the equine alveolus, including surface area and volume, were also compared to the human lung and were found to be less than the comparable human alveolar measurements. Sources of Carboxyhemoglobin in the Metropolitan St. Louis Population Gustave L. Davis, M.D., 1 George E. Gantner, Jr., M.D., 2 Alfred Kahn, M.S.,3 Jane W. Altes, M.A., 3 Robert B. Rutledge, Ph.D., 3 Norville D. Wallace, Ph.D., 3 and Charles A. Thornton, Ph.D. 1 Washington University School of Medicine, St. Louis, MO 2 St. Louis University School of Medicine, St. Louis, MO 3 Southern Illinois University, Edwardsville, IL Abstract of a paper presented at the March meeting of the Northeastern Regional Discussion Group, Stouffer’s Valley Forge Inn, King of Prussia, PA, March 22, 1974. I n order to ascertain the sources of carbon monoxide exposure of a metropolitan population, we obtained, from the Missouri-Illinois Red Cross Blood Program, 16,649 individual blood samples during a one-year period from 402 separate blood-mobile visits. Carboxyhemoglobin (COHb), determined with an Instrument Laboratories Model 182 Co-oximeter, was correlated with smoking histories, travel, and socioeconomic data obtained from donors during phlebotomy. Air monitoring data and traffic counts were obtained from cooperating governmental agencies. The mean COHb saturations of segments of the population studied were: Total (16,649) 2.30%; nonsmokers (10,157) 0.85%; smokers (6,492) 4.58%; industrial workers (3,261) 3.31%; other workers (13, 388) 2.05%; smoking industrial workers (1,738) 5.01%; nonsmoking industrial workers (1,523) 1.38%; smoking other workers (4,734) 4.42%; nonsmoking other workers (8,634) 0.75%. Travel time or distance to donor site prior to phlebotomy did not result in increased COHb levels and was, in fact, related to lowering of COHb levels among industrial workers. The significance of smoking as the prime source of COHb is well known. Industrial exposure to unknown or unsuspected CO sources is less well established, ranking second to smoking in our population. Other CO sources of ambient air exposure do not significantly contribute to the COHb burden of this St. Louis regional population. The relationship between environmental sources of CO and COHb burdens must be clarified prior to the establishment of national clean air standards since smoking and work place exposure are far more important sources of COHb than ambient air in the St. Louis region. Supported by National Science Foundation Grant GI-29900. Some Effects of Cadmium on the Small Intestine Mary E. Richardson, M.D. Environmental Protection Agency and Armed Forces Institute of Pathology, Washington, D.C. 20306 and M.R. Spivey Fox, Ph.D. Food and Drug Administration, Washington, D.C. 20204 Abstract of a paper presented at the March meeting of the Northeastern Regional Discussion Group, Stouffer’s Valley Forge Inn, King of Prussia, PA, March 22, 1974.of a paper presented at the March meeting of the Northeastern Regional Discussion Group, Stouffer’s Valley Forge Inn, King of Prussia, PA, March 22, 1974.