Showing papers on "Zinc published in 1968"
TL;DR: In this paper, an investigation was made of the uptake of trace elements from both distilled water and sea water by the chelating ion-exchange resins Chelex-100 and Permutit S1005.
424 citations
TL;DR: Using atomic absorption spectroscopy, it has been established that plasma zinc is one of the most uniform biochemical characteristics of normal adult blood as mentioned in this paper, and that sex and age differences in adult life are insignificant.
Abstract: Zinc is an essential trace element. Previous methods of measuring zinc in clinical material have been difficult and reported findings must be treated with caution. Using atomic absorption spectroscopy it has been established that plasma zinc is one of the most uniform biochemical characteristics of normal adult blood. Sex and age differences in adult life are insignificant. Increased metabolic activity, on the other hand, induces a marked, immediate fall in plasma zinc level. The possible implications of this are discussed. Zinc levels in patients with diabetes mellitus, cardiovascular disease, and anaemia due to acute blood loss have been within normal limits. Plasma zinc is low in certain types of liver disease.
211 citations
TL;DR: Though the intake of zinc and copper probably varies considerably, the majority of animals contain between 20 and 35 μg/g of both metals, probably because the concentrations in the body fluids and tissues are regulated.
Abstract: Concentrations of zinc and copper have been measured in 18 species of decapod crustaceans, ranging from freshwater to purely marine species. Although the intake of zinc and copper probably varies considerably, the majority of animals contain between 20 and 35 μg/g of both metals. This is probably because the concentrations in the body fluids and tissues are regulated. Reasons for differences between the concentrations of zinc and copper in the individual tissues of different species are discussed and the ways in which regulation is achieved are compared.
207 citations
166 citations
149 citations
Journal Article•
142 citations
TL;DR: In this article, the interstitial waters of four piston cores from the continental borderland area off the coast of Southern California were determined directly by atomic absorption spectrophotometry, and the trace elements: cadmium, cobalt, copper, iron, nickel and zinc, were determined by extraction of the chelate complexes with ammonium pyrollidine dithiocarbamate into methylisobutyl ketone and subsequent analysis.
119 citations
117 citations
TL;DR: All zinc oxide and eugenol cements and the epoxy resin, AH-26, are suitable root-canal sealers and the unmodified form is a very satisfactory root- canal cement.
111 citations
TL;DR: The concentrations of copper, zinc, iron, and magnesium have been determined by atomic absorption spectroscopy for various regions of the brain in cases restricted to non-neurologic disorders.
107 citations
TL;DR: A modified method is described for zinc determination in plasma by atomic absorption spectrophotometry using the Boling three-slot burner, with results similar to those obtained with trichloracetic acid filtrates and water standards.
Abstract: A modified method is described for zinc determination in plasma by atomic absorption spectrophotometry using the Boling three-slot burner. Accurate analysis for the element was accomplished after merely diluting the plasma with deionized water (1 part plasma to 1 part water). Sample preparation time was thus greatly decreased. It was found that standards made up in water resulted in an error of 33%. However, standards prepared in 3% dextran solution gave results similar to those obtained with trichloracetic acid filtrates and water standards. Dextran was found not to be contaminated with zinc. The recovery of zinc added to plasma averaged 98.9%. Because of the simplicity of the method, sources of error and possibilities for contamination were reduced.
TL;DR: A system for detecting the effects of metal ions, repressors, and mutations on the biosynthesis in vivo of alkaline phosphatase of Escherichia coli is described and shows that the conformation and quaternary structure of this product do not differ significantly from the enzyme synthesized in the presence of Zn(II).
TL;DR: The zinc, content of serum was consistently higher than the zinc concentration in plasma by an average of 16% and zinc was determined in platelets concentrated from 10 individuals and was present in a significant amount.
Abstract: SummaryThe zinc, content of serum was consistently higher than the zinc concentration in plasma by an average of 16%. Because platelets are largely disintegrated in the clotting process, zinc was determined in platelets concentrated from 10 individuals and was present in a significant amount. It was demonstrated that 39% of the increased concentration of zinc in serum can be attributed to a slightly greater dilution in plasma, 44% being derived from platelets and 4.0% from hemolysis. This is the first known report demonstrating zinc in platelets.
TL;DR: From inhibition data and metal analyses before and after inhibition, it is concluded that EDTA forms the inactive apoenzyme by removal of zinc from the active metalloenzyme.
TL;DR: The levels of Cu and Zn in blood in 17 locations were normally distributed about their means except in two locations, and the concentrations of Cd and Pb varied widely among samples from a given location.
Abstract: Copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) were determined in 243 blood samples of male residents of 19 cities in the continental United States. The mean Cu and Zn concentrations of all samples agreed closely with values reported by other investigators. The means among the 19 locations, however, differed by threefold in Cu and fivefold in Zn. The levels of Cu and Zn in blood in 17 locations were normally distributed about their means except in two locations. Unlike Cu and Zn, the concentrations of Cd and Pb varied widely among samples from a given location.
TL;DR: The toxicity of soft alkyl benzene sulphonate (ABS) to rainbow trout which had been chronically exposed (100 days) to water containing 0·8 mg Zn/l was compared with its toxicity to untreated control fish.
TL;DR: A new method for determining the correction factor of atomic absorption interference is described, which was used for measuring the zinc content, in ppb (μg/1), of brain tissue.
Abstract: —
Atomic absorption spectroscopy was used for measuring the zinc content, in ppb (μg/1), of brain tissue. A new method for determining the correction factor of atomic absorption interference is described.
Measurements of the zinc content of twenty-four regions of adult human brains showed the maximum zinc content in resistent sector and endplate of the Amnion's horn, corroborating the histochemical data. The distribution of zinc in other regions was relatively uniform, but white matter showed lower values than gray matter. The zinc content of seventeen regions of human newborn brains was below that in adult brains, for all regions. The blood content of brain tissue contributed only insignificantly to its zinc content.
TL;DR: Rainbow trout (Salmo gairdnerii Richardson) showed strong avoidance reactions to sub-lethal concentrations of zinc sulphate as mentioned in this paper, with threshold avoidance level 5.6 μg/l of zinc added to laboratory water.
TL;DR: Dietary zinc deficiency was shown to result in a rapid fall in the plasma zinc levels of pregnant female and weanling male rats and general food restriction elicited a similar response in pregnant females but not in young males.
Abstract: SummaryDietary zinc deficiency was shown to result in a rapid fall in the plasma zinc levels of pregnant female and weanling male rats. In both groups, plasma zinc fell to 45-60% of its original level after only one day on the deficiency regime. Longer periods of zinc depletion (21 days) were found to increase the ratio of PMN leukocytes to lymphocytes in the blood by a factor of 10. General food restriction elicited a similar response in pregnant females but not in young males. The zinc deficiency regime had no effect upon the total leukocyte count or upon the concentration of zinc in the leukocytes.
TL;DR: When eight plant species were grown in a flowing culture system over a range of constant zinc concentrations, all species produced maximum yields at concentrations of zinc in solution below those usually considered adequate for plant growth.
Abstract: When eight plant species were grown in a flowing culture system over a range of constant zinc concentrations, all species produced maximum yields at concentrations of zinc in solution below those usually considered adequate for plant growth. All species made good growth at a concentration of 0.01 µM zinc and maximal growth at 0.25 µM zinc or less. Toxicity effects were also induced at lower concentrations (1–6 µM) than previously reported. Differences in yield response among species did not agree in all cases with previously reported responses in standard culture and in the field. Disagreement between results in the flowing culture method used here and the standard methods of nutrient culture may arise from the contrasting characteristics of zinc supply under which deficiency develops. It is considered that results from both methods have relevance to the absorption of zinc by plants from soil solutions.
TL;DR: Potentiostatic polarization measurements on exposed (0001), (1010), and (1120) faces of single crystals and on polycrystalline zinc were made in aqueous solutions of sodium hydroxide as discussed by the authors.
Abstract: Potentiostatic polarization measurements on exposed (0001), (1010), and (1120) faces of single crystals and on polycrystalline zinc were made in aqueous solutions of sodium hydroxide. Crys...