Showing papers on "Zinc published in 1975"
309 citations
TL;DR: It is suggested that metallothionein is involved in the normal metabolism of zinc, perhaps in some temporary storage or detoxication capacity.
Abstract: The isolation of two forms of hepatic zinc-thioneins after either zinc injection into rats or partial restriction of their food intake is described. The proteins differed slightly in their amino acid composition and electrophoretic mobilities. Increases in liver zinc content after both treatments were synchronous with, and associated almost completely with, increased zinc-binding to these proteins. The time-course for the appearance and disappearance of the zinc proteins is shown. It is suggested that metallothionein is involved in the normal metabolism of zinc, perhaps in some temporary storage or detoxication capacity.
297 citations
TL;DR: An overall homeostatic mechanism is proposed where metallothionein synthesis is controlled at the transcriptional level by body zinc status and functions in uptake and storage of zinc in hepatocytes and in the intestinal mucosal cells.
277 citations
TL;DR: The therapeutic effect of orally administered zinc was evaluated in an adult woman with acrodermatitis enteropathica and resulted in rapid and complete clinical remission, and in a return of plasma zinc, serum alkaline phosphatase and urinary zinc excretion to normal.
Abstract: The therapeutic effect of orally administered zinc was evaluated in an adult woman with acrodermatitis enteropathica. When she was off therapy and in clinical relapse the plasma zinc concentration (10 mug per 100 ml), serum alkaline phosphatase (3 1U per liter) and urine zinc excretion rate (39 mug per 24 hours) were extremely low. Di-iodohydroxyquin therapy was accompanied by a modest increase in plasma zinc concentrations. Oral zinc sulfate (220 mg three times a day or 50 mg twice a day) resulted in rapid and complete clinical remission, and in a return of plasma zinc, serum alkaline phosphatase and urinary zinc excretion to normal. These data are compatible with a severe zinc deficiency state and indicate that the inherited defect in this disease is either in or closely related to zinc metabolism. The beneficial effects of zinc therapy in this patient provide further confirmation of the efficacy of oral zinc in the treatment of acrodermatitis enteropathica.
264 citations
TL;DR: The identity of the proteins induced in rats by zinc, mercury and silver with the previously known metallothionein induced by cadmium has been established.
240 citations
196 citations
TL;DR: It was shown that the variation in concentration of the non-essential elements in the different brain regions was greater than the corresponding variations in Concentration of the essential elements.
Abstract: Up to 60 tissue samples were dissected from 13 human brains in defined regions and were analysed by means of neutron activation analysis for trace element concentration of cobalt, iron, rubidium, selesium, zinc, chromium, silver, cesium, antimony and scandium. It was shown that the variation in concentration of the non-essential elements in the different brain regions was greater than the corresponding variations in concentration of the essential elements. The mean values of Fe and Rb concentrations were higher in the basal ganglia than in the cortex areas. With increasing age the Fe concentration in the human brain was found to increase and that of Rb to decrease. Comparison of the trace element concentration in corresponding areas of the right and left hemispheres showed highly significant positive correlations for the essential elements. The concentration of each of the essential elements Fe, Rb and Zn was also found to differ significantly between defined functional regions. The characteristic distribution of essential trace elements in different areas is discussed in the light of known metabolic functions of these elements.
170 citations
TL;DR: The in vitro and in vivo effects of copper, zinc, cadmium, nickel, cobalt, and manganese on nitrate reductase, malate dehydro-genase, isocitrate dehydrogenase, and glucose-6-phosphate dehydrogenases of zinc-, copper- and non-resistant populations of Silene cucubalus were investigated.
Abstract: The in vitro and in vivo effects of copper, zinc, cadmium, nickel, cobalt, and manganese on nitrate reductase, malate dehydro-genase, isocitrate dehydrogenase, and glucose-6-phosphate dehydrogenase of zinc-, copper- and non-resistant populations of Silene cucubalus were investigated. During the in vitro experiments no resistant enzyme could be detected; enzymes of resistant and non-resistant ecotypes had a similar sensibility to all the metals. Nitrate reductase was the most sensitive enzyme. During the in vivo experiments remarkable differences were found. The nitrate reductase and the isocitrate dehydrogenase of the zinc-resistant population were activated when adding zinc to the culture medium, especially the nitrate reductase showed high activities at zinc concentrations where the nitrate reductase of the non-zinc-resistant populations was nearly completely inhibited. The zinc-resistant ecotype had a real need for zinc.
162 citations
TL;DR: Copper concentrations of up to 15,000 μg/g dry weight were found in L. opalescens in conjunction with significant correlations between this element and Ag, Cd and Zn.
Abstract: Livers from 43 Loligo opalescens, 14 Ommastrephes bartrami, and 7 Symplectoteuthis oualaniensis were analyzed for their silver, cadmium, copper, zinc and iron contents. Copper concentrations of up to 15,000 μg/g dry weight were found in L. opalescens in conjunction with significant correlations between this element and Ag, Cd and Zn. The latter elements are known to affect Cu metabolism in terrestrial organisms; however, whether the correlations occurring in marine organisms represent casual, or cause and effect, relationships is as yet unknown.
161 citations
TL;DR: Results of a controlled trial with zinc supplementation in 14 to 19 year old sickle cell anemia subjects who were retarded in growth show that zinc supplementation significantly improved longitudinal growth and body weight.
Abstract: Clinical similarities between patients with sickle cell anemia and zinc-deficient subjects suggested a secondary zinc deficiency in sickle cell anemia. Zinc was assayed in various biological fluids and tissues by atomic absorption spectrophotometry. Zinc in the plasma, erythrocytes, and hair was decreased and urinary zinc excretion was increased in anemia patients as compared to controls. Erythrocyte zinc and daily urinary zinc excretion were inversely correlated in the anemia patients ( r = -.63, P < 0.05), suggesting that hyperzincuria may have caused zinc deficiency in these patients. Carbonic anhydrase, a zinc metalloenzyme, correlated significantly with erythrocyte zinc ( r = +0.94, P < 0.001). Plasma RNase activity was significantly greater in anemia subjects than in controls. We administered zinc sulfate, 660 mg per day, orally, to seven men and two women with sickle cell anemia. Two 17-year-old males gained 5 cm and 7 cm in height during 49 and 42 weeks of zinc therapy, respectively. All but one patient gained weight (0.5 kg to 4.1 kg). Five of the males showed increased growth of pubic, axillary, facial, and body hair, and in one a leg ulcer healed in six weeks on zinc and in two others some benefit of zinc therapy on healing of ulcers was noted.
156 citations
TL;DR: A critical and exhaustive review of published and unpublished data on the zinc content of foods showed that, with few exceptions, the major dietary sources of zinc were foods of animal origin.
Abstract: A critical and exhaustive review of published and unpublished data on the zinc content of foods showed that, with few exceptions, the major dietary sources of zinc were foods of animal origin. Oysters, which contained more than 5 mg. zinc per 3-oz. cooked portion, were an outstanding source of zinc. Lean beef and beef liver were also among the foods highest in zinc and ground beef was a good source. Dark meat of poultry contained more zinc than light meat, and turkey was higher in zinc than chicken. Egg yolk, but not egg white, was relatively high in zinc, as were nonfat dry milk and Cheddar cheese. Foods of plant origin, like those of animal origin, varied widely in zinc content. Cocoa and the milling fractions of bran and germ of wheat were high in zinc. Seeds of plants, such as muture dry legumes and peanuts, were better sources of zinc than were leaves, stalks, fruits, or roots. Vegetables, fruits, oils, fats, tea, coffee, and carbonated beverages contained little zinc. Factors influencing the zinc content of foods were evaluated. Provisional tables, giving representative values for zinc in more than two hundred foods, both in 100-gm. portions and in common household units, based on this research, are presented.
TL;DR: A zinc protein has been isolated and purified to apparent homogeneity from subjects with normal taste acuity by gel filtration and ion-exchange chromatography.
Abstract: A zinc protein has been isolated and purified to apparent homogeneity from subjects with normal taste acuity by gel filtration and ion-exchange chromatography The protein has a molecular weight of 37,000 and does not appear to have subunits It is composed of 8% histidine residues and has 2 moles of zinc per mole of protein
TL;DR: Rat erythrocyte δ-aminolevulinate dehydratase (ALA-D) has been confirmed to be an enzyme dependent on dietary zinc and, following the removal of lead exposure, the return of the enzymatic activity toward normal values was quicker in the animals receiving higher zinc than in those on lower zinc diet.
TL;DR: In this article, the uptake of cadmium by corn roots (Zea mays L.) and shoots from hydroponic solutions was determined over time intervals from 3 to 12 days.
Abstract: The uptake of cadmium by corn roots (Zea mays L.) and shoots from hydroponic solutions was determined over time intervals from 3–12 days. This uptake from solutions containing 1–40 mg cadmium/liter of solution was correlated with leaf chlorophyll content, dry matter production, and tissue concentration of zinc and iron. Cadmium concentration in roots and shoots increased with increased time of treatment. Roots of plants treated for 12 days contained about twice the cadmium found in shoots (approximately 200–1,100 µg cadmium/g dry weight in roots and approximately 100–450 µg cadmium/g dry weight in leaves). The dry weight of both roots and shoots, and of leaf chlorophyll concentration, decreased with increased cadmium tissue concentrations. The zinc concentration decreased, but the iron concentration increased, in leaves and roots as the cadmium concentration increased. These data resulted in a linear relationship between the increase of tissue cadmium and the increasing iron/zinc ratio. While the chlorosis of cadmium-treated leaves appeared to be comparable to that resulting from iron deficiency, the data presented indicate that an iron deficiency is not the cause of leaf chlorosis in cadmium-treated plants. A more important factor in cadmium toxicity may be the apparent correlation between an increase in tissue cadmium concentrations and the corresponding increase in the iron/zinc ratio.
TL;DR: Dairy products and brown bread decreased zinc absorption and Coffee seems to inhibit zinc absorption, and experiments in vitro have shown that zinc is precipitated by phosphate and phytate at pR values dose to that of the intestinal lumen.
Abstract: Single doses of zinc sulfate were given to healthy young volunteers, either in the fasting state or with various types of meals. Dairy products (milk and cheese) and brown bread decreased zinc absorption, as indicated by a significant drop in peak serum zinc levels. Zinc absorption was decreased when zinc was given in the fasting state with the same amounts of purified phosphate or phytate as those found in foods above. Experiments in vitro have shown that zinc is precipitated by phosphate and phytate at pH values close to that of the intestinal lumen. Coffee also seems to inhibit zinc absorption.
TL;DR: The absence of morphologic evidence to indicate that cell division has followed the doubling of the DNA, and the arrest in proliferation suggests that a critical zinc-dependent step in the cell cycle, localized to G2, is blocked in zinc deficiency.
Abstract: Euglena gracilis is a suitable model system to investigate the role of zinc in the process of cell division. In zinc-deficient organisms there is a characteristic arrest of cellular proliferation, the DNA content of the cells doubles, whereas RNA and protein contents decrease. The present investigations include the growth characteristics, changes in cellular morphology at various stages in the growth cycle, quantitation of zinc uptake and incorporation of tritium-labelled precursors into RNA by organisms grown in zinc sufficient (Zn+), (Zn2+ content 1 times 10-minus 5 M) or zinc-deficient (Zn minus), (Zn2+ content 1 times 10-7 M) medium. Cell division ceases on depletion of zinc from the medium. There are 20-fold less cells in (Zn minus) medium than in control cultures. The size of (Zn+) cells decreases during log phase due to a reduction in the paramylon content of the cytoplasm. The size of (Zn minus) cells, however, increases, due to an accumulation of paramylon. This results in a 13-fold increment in dry weight compared to control. Other cytoplasmic organelles, including Golgi bodies, mitochondria, etc. are normal. Nuclear morphology also is unchanged. There is a reduction in the rate of incorporation of labelled precursors into RNA by (Zn minus) cells. The DNA content of (Zn minus) E. gracilis, the absence of morphologic evidence to indicate that cell division has followed the doubling of the DNA, and the arrest in proliferation suggests that a critical zinc-dependent step in the cell cycle, localized to G2, is blocked in zinc deficiency.
TL;DR: The data suggest that zinc deficiency affects the utilization of vitamin A as well as the catabolism of ethanol in rats nursed by zinc-deficient dams, and the retina was more sensitive to the lack of dietary zinc than the liver.
Abstract: The zinc metalloenzyme alcohol dehydrogenase was assayed in subcellular fractions of liver and retina from zinc-deficient and control rats using retinol and ethanol as substrates. When the zinc concentrations of these tissues were reduced because of feeding inadequate dietary zinc, alcohol dehydrogenase was significantly lowered, and the retinol-retinal as well as the ethanol-ethyladehyde conversion was significantly reduced. While in older rats no changes occurred in liver zinc and alcohol dehydrogenase, the retina was more sensitive to the lack of dietary zinc than the liver. Young rats nursed by zinc-deficient dams showed the most severe changes in both tissues. The data suggest that zinc deficiency affects the utilization of vitamin A as well as the catabolism of ethanol.
TL;DR: The role of magnesium and other metal ions in regulatory processes, only now beginning to be explored fully, will likely emerge as an important avenue for achievement of regulatory effects in metalloenzymes.
Abstract: Alkaline phosphatase of E. coli, isolated by procedures which do not alter its intrinsic metal content, contains 1.3 +/- 0.3 g-atom of magnesium and 4.0 +/- 0.2 g-atom of zinc per molecule of molecular weight 89,000. Magnesium, the role of which has been unappreciated, significantly affects the function and structure of alkaline phosphatase containing either 2 or 4 g-atom of zinc per mole. Magnesium does not activate the apoenzyme but increases the activity of the enzyme containing 2 g-atom of zinc 4.4-fold and that of the enzyme containing 4 g-atom 1.2-fold. The results obtained with enzyme in which cobalt is substituted for zinc are analogous. Moreover, the absorption and electron paramagnetic resonance spectra of cobalt phosphatases reveal the effects of magnesium on cobalt coordination geometry. Addition of magnesium changes the spectral characteristics of the apoenzyme reconstituted with 2 g-atom of cobalt from predominantly octahedral to 4- or 5-coordinate geometry. These two classes of cobalt binding sites have been associated with catalysis and structure stabilization, respectively. Therefore, magnesium controls the occupancy of the catalytic and structural binding sites and modulates the resultant enzymatic activity. Hydrogen-tritium exchange was employed to determine the effects of magnesium on the conformational stability of phosphatase. Magnesium stabilizes the dynamic structural properties, both of apophosphatase and of enzyme containing 2 g-atom of zinc, which is further stabilized by 2 more zinc atoms. The role of magnesium and other metal ions in regulatory processes, only now beginning to be explored fully, will likely emerge as an important avenue for achievement of regulatory effects in metalloenzymes.
TL;DR: It is reported that divalent metal ion chelating agents effect a seven- to tenfold increase in the esteropeptidase activity of 7S NGF at pH 7.4, and that the zinc ion content of the system is critically dependent on the subunit aggregation state strongly suggests that zinc ion is an integral structural component of native 6S nerve growth factor.
Abstract: The 7S nerve growth factor (7S NGF) is an oligomeric protein consisting of three distinct classes of subunits, alpha,beta, and gamma (A. P. Smith, S. Varon, and E. M. Shooter (1968), Biochemistry 7, 3259). The beta subunit contains the growth promoting activity while gamma is a potent esteropeptidase. The proteolytic activity of gamma is virtually completely inhibited in the 7S NGF aggregate (L. A. Greene, E. M. Shooter, and S. Varon (1969), Biochemistry 8, 3735). In this paper, we report that divalent metal ion chelating agents effect a seven- to tenfold increase in the esteropeptidase activity of 7S NGF at pH 7.40. Plots of esteropeptidase activity vs. chelator concentration give saturation curves which are either sigmoidal (EDTA) or hyperbolic (o-phenanthroline) depending on the chemical structure of the chelator. A survey of common divalent metal ions shows that only zinc ion (Ki = 8 times 10(7) M) and, to a lesser extent, cadmium ion are effective, reversible inhibitors of both 7S NGF and the gamma subunit esteropeptidase activities. We have found that during isolation of 7S NGF, Zn2+ is selectively associated with the oligomer in a ratio of approximately 1-2 g-atoms of zinc/mol of 7S NGF with an apparent affinity which is orders of magnitude tighter than is indicated by the Ki value for the gamma subunit. Dialysis to pH 4.0 where 7S NGF is known to undergo a reversible dissociation (A. P. Smith, S. Varon, and E. M. Shooter (1968), Biochemistry 7, 3259) brings about a tenfold reduction in the zinc ion content of the protein. This reduction is reversed on dialysis back to pH 7.4. In contrast, the isolated subunits contain only trace amounts of zinc ion at pH 7.4. Preliminary metal ion exchange experiments indicate that, of the common metal ions known to substitute for zinc in other zinc-metalloproteins, only cadmium ion is effective in substituting for zinc ion in 7S NGF. The fact that zinc ion is specifically bound to native 7S NGF, and that the zinc ion content of the system is critically dependent on the subunit aggregation state strongly suggests that zinc ion is an integral structural component of native 7S NGF.
TL;DR: In this paper, changes in buccal and opercular pressure amplitude, as well as ventilation and coughing frequency were monitored in rainbow trout using catheterization of respiratory cavities and pressure transducers.
TL;DR: Anin situ morphological study of the oxidation of electron transparent specimens of aluminum and aluminum alloys containing zinc and magnesium has been carried out in the temperature range 400 to 520°C using the hot stage of a 1 MeV transmission electron microscope as mentioned in this paper.
Abstract: Anin situ morphological study of the oxidation of electron transparent specimens of aluminum and aluminum alloys containing zinc and magnesium has been carried out in the temperature range 400 to 520°C using the hot stage of a 1 MeV transmission electron microscope. The structure and morphology of the crystalline oxide produced in each alloy has been carefully examined by selected area electron diffraction and stereomicroscopy. In pure aluminum, oxidation takes place after a temperature dependent induction period, by the nucleation of crystalline γ-Al2O3 at the amorphous oxide/metal interface. This process is delayed by additions of zinc which modify the structure of the oxide. In alloys containing magnesium, oxidation takes place by the rapid nucleation and growth of MgAl2O4 or MgO, with a secondary form of magnesia developing from the reduction of the amorphous γ-Al2O3 surface layer.
TL;DR: A comparison of the zinc level in barnacles with those recorded for some other marine organisms indicates the possible usefulness of barnacles as indicators of zinc pollution.
Abstract: Barnacles [Balanus balanoides (L.), Elminius modestus Darwin, Lepas anatifera (L.)] from several different sites were found to accumulate the heavy metal zinc. The majority of the zinc was deposited in the tissues associated with the gut, and the level of zinc in soft body tissue generally reflected well the level of zinc in the immediate sea-water environment. The zinc accumulated in the gut tissues was in the form of discrete granules, mainly within the parenchyma cells which surround the gut. These granules probably exist as an insoluble zinc salt. A comparison of the zinc level in barnacles with those recorded for some other marine organisms indicates the possible usefulness of barnacles as indicators of zinc pollution.
TL;DR: In this article, a detailed comparison of the cadmium, copper and zinc contents of Fucus vesiculosus at various sites in the Bristol Channel with a detailed investigation of the dissolved trace metal concentrations to which they are subjected, demonstrates the passive nature of the accumulation.
TL;DR: Three groups of Atlantic salmon (Salmo salar) parr were acclimated to water temperatures of 3, 11, and 19 C and exposed at their acclimation temperature to lethal concentrations of zinc, cold-acclimated salmon survived longer than warm-acClimated salmon, but the threshold lethal concentration (LC50) of zinc was highest for salmon at 19“C, i.e. there was less toxicity at the high temperature.
Abstract: Three groups of Atlantic salmon (Salmo salar) parr were acclimated to water temperatures of 3, 11, and 19 C. When exposed at their acclimation temperature to lethal concentrations of zinc, cold-acclimated salmon survived longer than warm-acclimated salmon. However, the threshold lethal concentration (LC50) of zinc was highest for salmon at 19 C, i.e. there was less toxicity at the high temperature. At test temperatures lower than prior acclimation temperatures, survival times in zinc were longer but the threshold LC50 was lower, i.e. fish were less tolerant of zinc. The opposite results were seen at temperatures above prior acclimation temperatures.The threshold LC50 may be predicted by the equation LC50 = 1.9611 − 0.1873 Ta + 0.8699 Te − 0.0414 Te2 + 0.00004 Ta Te3, where Ta = temperature of acclimation and Te = temperature of exposure.In polluted rivers, zinc concentrations may be most damaging to fish populations during the winter months. Measured concentrations of zinc and copper in the Miramichi Rive...
TL;DR: In this paper, the stability of heavy metal sulfides (MnS, FeS, ZnS and CuS) in aerobic and anaerobic soil was studied, and water extracts of each treated soil were made regularly during a 75-day incubation period.
Abstract: The stability of heavy metal sulfides (MnS, FeS, ZnS, CuS, and HgS tagged with 35S) in aerobic and anaerobic soil was studied. The sulfides are listed in decreasing order of solubility. Water extracts of each treated soil were made regularly during a 75-day incubation period. The radioactivi
TL;DR: In this article, the authors showed that different zinc levels had no effect on copper uptake and conversely, copper had not effect on zinc uptake and that there was, however, a strong interaction in the toxic effects of zinc and copper as measured by root elongation.
Abstract: SUMMARY
Zinc and copper uptake by Agrostis stolonifera, tolerant to both zinc and copper, showed that different zinc levels had no effect on copper uptake and, conversely, copper had no effect on zinc uptake. There was, however, a strong interaction in the toxic effects of zinc and copper as measured by root elongation. The mechanisms of zinc and copper tolerance are therefore independent even when they act in the same individual.
TL;DR: Addition of an equal volume of 20% polyethylene glycol 6000 to human serum leads to separation of two major zinc ligands, α2-Macroglobulin, a zinc metalloprotein, is precipitated, while albumin, which forms a zinc-protein complex in serum, remains soluble.
TL;DR: Results of the present study indicate that transient peaks in the concentration of bicarbonate and possibly of organic acids in the soil solution following soil submergence may induce temporary zinc deficiencies.
Abstract: Solution culture studies revealed no marked difference in the ability of the resistant variety IR8 or the susceptible variety IR184-67 to absorb zinc from low external concentrations comparable with those occurring in the soil solutions of deficient soils. However IR8 appeared to have a slightly lower tissue requirement for zinc than IR184-67 (critical values 0.23 and 0.27 μg atoms/g respectively) and IR8 was significantly less susceptible to bicarbonate concentrations (<1 mM). Despite these differences, the two varieties appeared equally susceptible to zinc deficiency during the first four weeks of growth under field conditions.
TL;DR: A method of analysis for copper, cadmium, and zinc in a 15-mg sample of human liver by atomic absorption spectrophotometry is described, which can be easily and reliably applied to small samples of liver obtained by closed-needle biopsy.
Abstract: We describe a method of analysis for copper, cadmium, and zinc in a 15-mg (wet weight) sample of human liver by atomic absorption spectrophotometry. The sample is digested with nitric acid (1.0 mol/liter), evaporated, and dilute HNO 3 (10 mmol/liter) added. The reconstituted acid mixture is injected into the graphite tube atomizer for analysis of Cu and Cd and aspirated into the airacetylene flame for measurement of Zn. The absorbance for each metal is suppressed with increasing pH. NaNO 3 , KNO 3 , KCl, and NaCl (e.g.) quench the Cd absorbance in acid solutions that contain no protein, but not in the presence of protein. Metal ions added to the predigestion human liver sample at 10% and 100% of the intrinsic metal concentrations were, respectively, 93% and 90% accounted for analytically in the case of Cu, 98% and 102% for Zn, and 101% and 93% for Cd. Analysis of a National Bureau of Standards9 Bovine Liver Standard Reference Material yielded results corresponding to 99% (Cu), 112% (Zn), and 91% (Cd) of the mean expected concentrations of these metals. The between-run coefficient of variation for the bovine liver material was 6% for Cu, 9% for Zn, and 10% for Cd. For 16 histologically normal samples of human liver, the mean values were: Cu, 26; Zn, 293; and Cd, 6.0 nanograms of metal per milligram dry weight, in agreement with values published previously. The method can be easily and reliably applied to small samples of liver obtained by closed-needle biopsy.