Effect of dietary protein, zinc, and carbon monoxide on fetal zinc concentration in mice

Dietary protein and zinc deficiencies known to be detrimental to the developing fetus are common in pregnant women in developing countries. Everyone in modern society is at risk of exposure to carbon monoxide (CO). This study was conducted to observe the effect of dietary protein, zinc, and exposure to CO on the fetal zinc concentrations by factorial experimentation. Pregnant mice of CD-1 strain were maintained on 17% (control) or 9% (deficient) protein diets mixed with deficient, normal (control), or supplemental zinc throughout gestation. The dams in each dietary group were exposed to air (control) or 500 ppm CO in air in environmental chambers from gestation day 8 to gestational day 18. The dams were sacrificed on d 18 and fetal zinc levels were measured by atomic absorption spectrophotometry. Carbon monoxide levels used in this study had no significant effect on fetal zinc concentration in any treatment group. When both dietary protein and zinc levels were normal, the mean fetal zinc concentrations were higher than all other dietary protein/zinc combinations (15.2±6.0 and 14.2±4.1 μg Zn/g of tissue for 0 and 500 ppm CO levels). However, when dietary protein levels were deficient, supplemental zinc increased the fetal zinc concentrations significantly (12.7±3.8 and 13.1±0.3.6 μg Zn/g of tissue, in 0 and 500 ppm CO groups) as compared to zinc-deficient groups (8.7±3.0 and 10.0±3.3 μg Zn/g of tissue in 0 and 500 ppm CO groups). The results of this study may be relevant to populations that experience both marginal zinc and protein diets during gestation.     

Relationship of dietary zinc to 6-mercaptopurine teratogenesis and DNA metabolism in the rat

The possible interaction between the level of maternal dietary zinc and the teratogenic activity of 6-mercaptopurine was investigated. Pregnant Sprague-Dawley rats were fed diets containing 9,100 or 1,000 ppm zinc from day zero of pregnancy and were given a single intraperitoneal injection of 6-MP (55mg/kg) on day 11. At term, females in the group fed 1,000 ppm zinc (a high intake) showed less pronounced effects on reproduction and embryogenesis than did those fed 9 ppm (marginally deficient) or 100 ppm (normal) zinc. Embryos examined on day 12 of gestation had similar concentrations of protein and RNA; however, the DNA content was lower and the incorporation of 3H-thymidine was greater in the drug treated groups than in non-drug treated controls. These results indicate that 6-mercaptopurine is acting to alter embryonic DNA metabolism and that high levesl of dietary zinc may ameliorate some of the deleterious effects of this drug on embryonic and maternal toxicity.     

The use ofZoogloea ramigera in waste water treatment containing Cr(VI) and Cd(II) ions

Summary Optimum fermentation conditions forZ. ramigera were determined and various parameters which affected adsorption rates of chromium and cadmium ions onZ. ramigera were investigated. At 25°C the optimum adsorption pH of Cr(VI) and Cd(II) ions were 2.0 and 6.0 respectively. The adsorption rate of chromium and cadmium ion increased by increasing initial metal ion concentration up to 75 and 50 ppm respectively: at higher initial metal ion concentrations, the adsorption rates decreased.     

Significance of digging behavior to mortality of red imported fire ant workers, Solenopsis invicta, in fipronil-treated sand

The effect of fipronil-treated sand on digging behavior and mortality of red imported fire ant, Solenopsis invicta Buren, workers was examined in the laboratory. No-choice digging bioassays where fipronil-treated sand was the only available digging substrate were conducted on two colonies at fipronil concentrations of 0.00, 0.05, 0.10, 0.50, 1.00, 1.50, and 2.00 ppm. Workers dug into the fipronil-treated sand in all cases, even at 2.0 ppm level, which caused 100% mortality in acute toxicity tests for both colonies. At 1.5 and 2.0 ppm, workers from the less sensitive colony had significantly higher mortality than those from the more sensitive colony, which might be explained by the significantly higher digging activity of the less sensitive colony. In two-choice digging bioassays where untreated sand was also available, workers dug into the fipronil-treated sand in 29 of 30 cases, even at 10.0 ppm level. At 1.0 and 10.0 ppm, mortality was positively correlated to digging effort in treated sand; however, such correlation was significant only at 1.0 ppm level. This indicates that digging did affect mortality; however, such effect is concentration dependent.     

The effect of various dietary zinc concentrations on the biological interactions of zinc,copper, and iron in rats

Three groups (14 rats each) were fed one of the following diets for 8 wks: a control purified basal diet containing 12 ppm zinc, 5 ppm copper, and 35 ppm iron; the basal diet with less than 2 ppm zinc; or the basal diet supplemented with 1000 ppm zinc. Rats fed the zinc-deficient diet had decreased weight gain, moderate polydipsia, and intermittent mild diarrhea. The zinc-supplemented rats had a cyclical pattern of food intake and weight loss from weeks 5 to 8. Tissue concentrations suggest that zinc and copper were not mutually antagonistic with chronic dietary imbalances. If tissue element concentrations reflected intestinal uptake, then competition and/or inhibition of intestinal uptake occurred between zinc and iron. The fluctuations in tissue element concentrations that occurred with increased duration of the study were at variance with previous studies of shorter time periods. The dietary proportions of zinc, copper, and iron appear to influence zinc, copper, and iron metabolism at the intestinal and cellular transport levels over a given period of time.     

Forest leaf litter decomposition in the vicinity of a zinc smelter

Summary Concentrations of about 26,000 ppm Zn, 10,000 ppm Fe, 2,300 ppm Pb, 900 ppm Cd, 340 ppm Cu, and 0.40% S were measured in the O₂ litter horizon about 1 km from a zinc smelter at Palmerton, Pennsylvania. Samples taken about 6 km east of the smelter had concentrations of about 15,000 ppm Zn, 6,500 ppm Fe, 970 ppm Pb, 250 ppm Cd, 170 ppm Cu, and 0.26% S. Samples from a control area about 40 km east of the smelter had concentrations of 2,800 ppm Fe, 650 ppm Zn, 260 ppm Pb, 50 ppm Cu, 9 ppm Cd, and 0.13% S.Litter bags were used to estimate first-year weight loss in sassafras leaves and a mixture of chestnut oak/red oak leaves in the three sites. At the end of one year, average weight loss for sassafras was 39.3% in the control site, 21.8% at 6 km, and 17.5% at the 1 km site. For the chestnut oak/red oak mixture, average weight loss was 36.8% (40 km), 25.7% (6 km), and 19.1% (1 km). Numbers and diversity of soil microarthropods inhabiting the litter bags showed a corresponding decline at sites near the smelter. Concentrations of Ca, Cd, Cr, Cu, Fe, Mg, Mn, N, Na, Ni, P, Pb, S and Zn in the decomposing litter were also measured.The average amount of organic matter on the forest floor was estimated to be 3.8 kg/m² in the control site, about 3.8 kg/m² at 6 km, and about 8.1 kg/m² 1 km from the smelter. Average thickness of the litter horizons in these three sites was 6.0 cm (40 km), 7.0 cm (6 km), and 12.4 cm (1 km), suggesting a long-term depression of decomposition and mineral cycling near the smelter.     

Toxicity of zinc to schistosoma Mansoni Cercariae in a Chemically Defined Water Medium

Time-until-death studies were run on cercariae of Schistosoma mansoni in 15 concentrations of zinc (from zinc sulfate) ranging from 57.6 ppm to 1 ppb. A chemically defined water medium was used for the dilution and control medium, and a partially enclosed slide chamber was perfected for the detailed observation of test cercariae. In concentrations of less than 57.6 ppm, zinc was found to have little lethal effect on cercariae during that period in which these larvae were most likely to be infective (0–6 hours) after emergence. Zinc concentration of 1 ppb killed all test cercariae within 46 hours at 21–22°C.At the highest concentration tested, 57.6 ppm zinc immobilized all test organisms within 6 hours at 21–2°C. The average time for 100 percent mortality for the control was 49 hours. The cercaricidal effects of zinc were shown to be insignificant in concentrations that would not be detrimental to other aquatic organisms.     

Effectiveness of 1-bromo-3-chloro-5,5-dimethylhydantoin against Legionella pneumophila in a cooling tower

Cooling towers are considered to be man-made amplifiers of Legionella spp. Thus, the proper maintenance and choice of biocides is important. The only biocidal measure that has thus far been shown to be effective in field tests is the judicious use of chlorination. Perturbation studies with 1-bromo-3-chloro-5, 5-dimethylhydantoin (Bromicide; Great Lakes Chemical Corp., West Lafayette, Ind.) (BCD) were conducted on an industrial cooling tower shown to contain Legionella pneumophila. At the concentrations recommended by the manufacturer, neither the density nor the activity of L. pneumophila was affected. At comcentrations greater than 2.0 ppm (2.0 micorgram/ml) free of residual, BCD was not effective in reducing L. pneumophila to source water concentrations, nor was it effective in reducing the 2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride activity of the bacterium in situ. The data indicate that at concentrations up to 2.0 ppm, BCD is not effective in these tower studies.     

Effectiveness of 1-bromo-3-chloro-5,5-dimethylhydantoin against Legionella pneumophila in a cooling tower.

Cooling towers are considered to be man-made amplifiers of Legionella spp. Thus, the proper maintenance and choice of biocides is important. The only biocidal measure that has thus far been shown to be effective in field tests is the judicious use of chlorination. Perturbation studies with 1-bromo-3-chloro-5, 5-dimethylhydantoin (Bromicide; Great Lakes Chemical Corp., West Lafayette, Ind.) (BCD) were conducted on an industrial cooling tower shown to contain Legionella pneumophila. At the concentrations recommended by the manufacturer, neither the density nor the activity of L. pneumophila was affected. At comcentrations greater than 2.0 ppm (2.0 micorgram/ml) free of residual, BCD was not effective in reducing L. pneumophila to source water concentrations, nor was it effective in reducing the 2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride activity of the bacterium in situ. The data indicate that at concentrations up to 2.0 ppm, BCD is not effective in these tower studies.     

Comparative study of copper and zinc metabolism in cattle and camel

At an experimental farm, five camels and five cows were fed a similar basal diet for 6 mo. They received oral trace element supplementation for 3 mo (day 22–112). This supplementation included zinc, copper, selenium, managanese, iodine, and cobalt, and corresponded to twice the requirements generally recommended for cows. Plasma copper and zinc concentrations were significantly lower in the camels (61 μg/100 mL for copper and 38 μg/100 mL for zinc) than in the cows (111 and 83, respectively). The supplementation had no effect on plasma zinc concentration in the camels in spite of the low observed values in this species. Liver copper concentration at the beginning of the trial was lower in the camels (9 ppm) than in the cows (35 ppm), and stayed at lower levels during the entire supplementation period. There was no clear difference in fecal excretion of copper and zinc between the camels and the cows. The results suggested that trace element requirements are lower in camels than in cows and that camels regulate their plasma zinc concentration at a very low level (<40 μg/100 mL).     

Inhibition of the genesis of spontaneous mammary tumors in C3H mice: effects of selenium and of selenium-antagonistic elements and their possible role in human breast cancer.

The inhibitory effect of selenium on the genesis of spontaneous mammary tumors in C3H mice is statistically significant even at toxic levels of selenium (5 and 15 ppm of Se in form of selenite added to the supply water), no evidence for stimulation of tumor growth by selenium has been obtained. Arsenite lowers the tumor incidence at higher dosage (80 ppm of As in supply water) as well, but animals developing tumors under these conditions demonstrate significantly enhanced tumor growth rates. The addition of subtoxic concentrations of zinc (200 ppm in form of ZnCl2) to supply water containing 5 ppm of Se abolishes the cancer-protecting effect of selenium. The latter result is of possible importance with respect to the human breast cancer mortality experience: The calculated dietary zinc intakes of average adults in 28 countries correlate with the female age-corrected mortalities from breast cancer directly, with P less than 0.005. The zinc concentrations in whole blood from donors in different parts of the U.S.A. are also directly correlated with the female breast cancer mortalities.     

Heavy metals in white-tailed deer living near a zinc smelter in Pennsylvania

White-tailed deer (Odocoileus virginianus (Zimmermann) shot within 20 km of the zinc smelters in the Palmerton, Pennsylvania area contained extremely high renal concentrations of cadmium (372 ppm dry weight (dw] and zinc (600 ppm dw). The deer with the highest renal zinc concentration was shot 4 km from the smelters and had joint lesions similar to those seen in zinc-poisoned horses from the same area. The highest concentrations of lead in both hard and soft tissues were relatively low, 10.9 ppm dw in a sample of teeth, 17.4 ppm dw in a metacarpus, and 4.9 ppm dw in a kidney.     

The effect of sodium selenite toxicity on tissue distribution of zinc,iron, and copper in rats

Male Sprague-Dawley rats were used to determine the effects of suptoxic and toxic concentrations of selenite in the drinking water on tissue distribution of zinc (Zn), iron (Fe), and copper (Cu). Se (as sodium selenite) was provided in drinking water at concentrations of 0, 2, 4, and 8 ppm. At 19 d, half of the rats in 4 and 8 ppm Sesupplemented groups were kept on drinking water alone for additional 13 d. All rats were sacrificed at the end of 32 d of experiment. Heart, liver, and kidney were analyzed for the concentrations of Fe, Zn, and Cu by atomic absorption spectrophotometry and of Se by a fluorometric method. Results indicated that rats receiving 4 and 8 ppm Se in drinking water showed a marked reduction in food intake and a reduced growth rate. These adverse effects were quickly reversed when high Se intake was discontinued. Se toxicity caused minimal change in zinc status, reduced tissue iron concentrations and caused a marked increase in copper contents in heart, liver, and kidney. The latter findings were only partly reversed after removal of Se in drinking water. The accumulation of Cu in the tissues of Se-toxic rats provides the evidence of some interaction between Se and Cu.     

Influence of Incubation Solution on the Rate of Recovery of Pratylenchus brachyurus from Cotton Roots

The rate of recovery of Pratylenchus brachyurus from cotton roots was enhanced when the tissue was incubated in solutions containing 10 ppm ethoxyethyl mercuric chloride, 50 ppm dihydrostreptomycin sulfate, 50, 100, or 1,000 ppm diisobutylphenoxethyl dimethyl benzyl ammonium chloride, or mixtures of these compounds. Incubation in 10 or 100 ppm zinc sulfate, zinc chloride, or magnesium chloride also enhanced the rate of recovery. Incubation solutions containing 1 or 1,000 ppm zinc chloride or magnesium chloride had no influence on this phenomenon, whereas, 10,000 ppm zinc sulfate, zinc chloride, or magnesium chloride retarded the rate of recovery. A t all incubation intervals during the first 21 days after the roots were removed from soil, the P. brachyurus population consisted of approximately 25% second-stage juveniles, 44% third and fourth-stage juveniles, and 31% females. At least 88% of the second-stage juveniles and 51% of the third and fourth-stage juveniles passed through a single 325-mesh sieve, whereas, 84% of the females collected were retained on a sieve of this mesh.     

Role of vitamin-zinc interactions on in vitro zinc uptake by human erythrocytes

In vitro zinc uptake by human erythrocytes was studied under a range of zinc concentrations representing three different plasma zinc levels i.e., zinc deficient [0.35–0.61 ppm], zinc normal [0.74–1.59 ppm], and zinc excess [1.65–2.3 ppm]. Further, interactions of physiological levels of riboflavin, flavin adenine dinucleotide (FAD), nicotinic acid, nicotinamide adenine dinucleotide (NAD), thiamine, thiamine pyrophosphate (TPP), folic acid, and ascorbic acid with zinc uptakes were studied in independent experiments. In control experiments, as compared to the normal zinc state, the rate of change of zinc uptake over change in zinc levels was 1.6 times in the excess state and 0.12 times in the deficient state, indicating three distinct patterns. Under the zinc-deficient state, thiamine significantly enhanced the zinc uptakes (p<0.05), whereas ascorbic acid and riboflavin inhibited zinc uptakes (p<0.05). The percent hemolysis of the cells was also significantly lower in the presence of thiamine (p<0.05). Under normal and excess zinc states, the vitamin-zinc interactions were not significant. The results suggest that with erythrocytes as the vehicles, thiamine might be playing an enhancer role in uptake of zinc, whereas the action of ascorbic acid might be inhibitory for zinc uptakes under deficient zinc states.     

The effect of zinc deficiency and food restriction on prostaglandin E2 and thromboxane B2 in saliva and plasma of rats

Zinc has been implicated in the regulation of prostaglandins and other arachidonic acid derivatives. Studies of zinc-deficient animals, however, are compromised by concomitant reduction in food intake that may also alter eicosanoid levels in body tissues and fluids. In this study, three groups of rats, designated as zinc-deficient, pair-fed and control, were fed diets containing 1 ppm, 15 ppm (in amounts paired to deficient rats) and 15 ppm Zn ad libitum, respectively, for 6 weeks. Saliva and blood were analyzed for PGE2 and TXB2 by radioimmunoassay. Saliva concentrations of both eicosanoids were lower (p less than 0.05) in the pair-fed animals, but not significantly altered by zinc deficiency. Plasma levels of PGE2 and TXB2 were unchanged by either zinc deficiency or food restriction. The results of this study support the contention that the effect of zinc on these prostaglandins is not mediated by altered rates of synthesis or degradation but rather by effects on eicosanoid function.     

Failure of cis-platinum to alter metal concentrations in the liver and kidney of the rat

The anticancer drug, cis-diamminedichloroplatinum, was administered to male rats at a dose of 0.5, 1.0, 2.0 or 4.0 mg platinum/kg body weight. After 48 hrs, the animals were killed and platinum, zinc, copper and metallothionein were measured in renal and hepatic tissue and platinum, zinc and copper were measured in the plasma. Administration of this platinum-containing compound did not induce hepatic or renal metallothionein and did not significantly alter the concentrations of copper or zinc in hepatic or renal tissue or in the plasma.     

Zinc content of the gills of rainbow trout (S. gairdneri) after treatment with zinc solutions under normoxic and hypoxic conditions

Forty specimens of rainbow trout (54–127 g) were divided into 4 groups which were treated as follows: (a) normoxic clean water; (b) hypoxic clean water; (c) normoxic water with 10 ppm zinc for 10 h; (d) hypoxic water with 10 ppm zinc for 10 h. The zinc content was determined separately for each of the 4 gill arches on each side of the fish. Values for the zinc concentration were greater following the zinc treatments, but no significant difference between hypoxia and normoxia was observed. Differences in concentrations of zinc were found in different arches whether expressed per gram dry weight or per unit surface area of the secondary lamellae.     

The distribution of zinc and copper in plasma, erythrocytes and erythrocyte membranes of rainbow trout (Salmo gairdneri)

1. The zinc and copper concentration of plasma was determined in rainbow trout, lake trout, walleye and whitefish. 2. These fish had mean plasma zinc concentrations ranging from 9.3 to 15.1 ppm and copper concentrations from 0.6 to 1.3 ppm. 3. In rainbow trout, the concentration of zinc and copper is greater in the erythrocyte membrane than in the total erythrocyte. 4. Ultrafilterable plasma zinc and copper concentration in rainbow trout was determined to be 0.03 and 0.019 ppm, respectively. 5. Dialysis of rainbow trout plasma against 20 mM EDTA results in removal of 99% of the zinc and 88% of the copper from plasma proteins.     

Anti-coccidial activity of 2-picoline, 6-amino-4-nitro-, 1-oxide

An investigational drug (2-picoline, 6-amino-4-nitro-, 1-oxide) was evaluated to characterize the anti-coccidial spectrum of the compound. Two concentrations of the drug (125 and 250 ppm) were evaluated for bioactivity; weight gain, survival, dropping, and lesion scores were the response variables utilized to ascertain activity. The activities of the picoline derivative were compared with monensin, maduramicin, and a narasin/nicarbazin (1:1) combination. The investigational drug had significant activity against Eimeria tenella and Eimeria necatrix, and the 250-ppm level was significantly more active than 125 ppm. At 250 ppm, the E. tenella activity of the picoline derivative was comparable to both monensin (120 ppm) and the 50-ppm narasin/nicarbazin combination, significantly less effective than maduramicin (6 ppm), and significantly more efficacious than 30 ppm narasin/nicarbazin. At the same level (250 ppm), the picoline derivative had significantly less E. necatrix activity than monensin (120 ppm), maduramicin (6 ppm), and narasin/nicarbazin (50 ppm), and significantly greater activity than 30 ppm narasin/nicarbazin. At best, only extremely weak Eimeria acervulina, Eimeria brunetti, and Eimeria maxima activities were noted with the investigational drug; higher concentrations of the picoline derivative may achieve greater anti-coccidial activity against these species. The efficacy of narasin/nicarbazin compared favorably with monensin and maduramicin; the 50-ppm level of the combination appeared significantly more efficacious than 30-ppm.