Distribution Of 65Zn Research Articles

Uptake and distribution of gamma-emitting activation products 59Fe, 58Co, 54Mn and 65Zn in plants

The comparative uptake by maize ( Zea mays L.) and bean ( Phaseolus vulgaris L.) plants of gamma-emitting activation products 59Fe, 58Co, 54Mn and 65Zn, which may be released in controlled or accidental discharges from nuclear installations, was examined in nutrient culture experiments. The accumulation in aerial tissues of 65Zn and 54Mn was greater than that of 58Co and 59Fe for identical plant growth periods. The distribution of 59Fe, 58Co and 65Zn in the organs of bean plants was generally uniform whereas the distribution of 54Mn was markedly acropetal in amount. Chemical fractionation of these activation products accumulated in the edible bean pods indicated substantial distribution of 59Fe, 58Co and 65Zn in the lipids, including lipophyllic pigments, free amino acids and amino sugars (ethanol) fraction) and also with ionic forms, including salts of organic acids, phosphates, carbonates and some protein bound forms extracted with weak mineral acids (acid fraction); the 54Mn was present only in the acid fraction.

Absorption, retention and excretion of 65Zn in rats with wounds treated with 65Zn-labelled zinc tape.

Absorption, retention and excretion of 65Zn in rats from excisional wounds treated with 65Zn-labelled zinc tape were studied. The absorption of 65Zn was marked and indicates that the absorption of zinc from the tape is more than sufficient to account for the increases in zinc concentrations seen in several tissues. The distribution, retention and excretion of 65Zn from the zinc tape followed a pattern similar to that of 65Zn injected into non-operated and operated rats. This indicates that the zinc from the tape is present in the body not as zinc oxide, as it is in the adhesive substance of the tape, but as zinc in those forms which are originally found in the body and that zinc oxide is ionized before absorption. In tissues with a rapid uptake of zinc more than 50% of the total concentration of zinc derived from the zinc tape after eight days of treatment. In operated animals which were not treated with zinc tape a decline was seen in the serum zinc concentration and excretion of zinc with a concomitant increase in the liver concentration of zinc.

Labile pool and selective distribution of zinc in soils

The labile pool of zinc in alkaline soils was determined by the application of isotopic dilution principle under laboratory and greenhouse conditions using corn and wheat as experimental crops. Simultaneously, the selective distribution of65Zn isotope between the solid and solution phases in 0.1M CaCl2 was determined. The labile pool-selective distribution coefficient diagrams were used for delineating the soils into different categories of Zn availability. The variations of the parameters of zinc availability were related to the physical and chemical properties of the soils. The results indicated that the plants and the DTPA extractant removed forms of zinc that may not undergo isotopic exchange in indifferent electrolytes. The values of labile pool obtained by the laboratory and greenhouse methods were highly correlated. The selective distribution coefficient was related to the organic matter and clay contents of the soils (R=0.78). A comparison of the values of labile pool of zinc measured with corn and wheat crops indicated that the two crops differ appreciably in affecting the isotopic dilution of65Zn in their root zone. The results indicate that the greenhouse method of determining the labile pool of zinc may be used as a reference procedure for calibrating soil test methods that extract amounts of Zn equal or proportional to that removed by growing plants in alkaline soils. The DTPA procedure of determining the available Zn in such soils meets the requirements of a satisfactory soil test method. re]19760726

Autoradiography of 65zinc in developing rat teeth and bones

The distribution of 65Zn in young rats was studied by whole-body autoradiography following single and repeated intraperitoneal injections of the isotope. The distribution of Zn after repeated injections was similar to that after a single injection. There was very slow release of the isotope from the site of injection. The liver showed a high concentration of 65Zn a few hours after injection. Zn concentration gradually increased in bone and dentine during the following days, eventually becoming the highest in the body. No 65Zn was found in cartilage. Only traces, if any, were detected in developing enamel.

65Zn tissue distribution in lactating Holstein cows fed normal and low-zinc practical diets.

Following oral dosing, tissue distribution of 65Zn and zinc specific activity were studied in first-lactation Holstein cows fed a low-zinc diet (16.6 ppm Zn) and the same diet supplemented with ZnO to provide 39.5 ppm total zinc in the ration dry matter. Low dietary zinc increased (P<.05−P<.01) 65Zn and zinc specific activity in all body tissues studied, except rib cartilage, 17 days after dosing with the effects greater in the biologically more active tissues. A part of the increased retention was due to higher 65Zn absorption. All sections of the gastrointestinal tract tissues and digestive tract contents from the low-zinc fed cows contained more 65Zn and had higher zinc specific activity than in controls (P<.01). The 65Zn content of whole blood, plasma, red blood cells (RBC) and the zinc specific activity in plasma and RBC of the low-zinc fed cows were more than twice that of controls. Peak 65Zn blood levels were reached on or prior to day 2 after dosing, then declined moderately until day 14. In RBC, 65Zn of the low-zinc cows increased sharply to day 7 then leveled off, whereas, that in RBC of control cows was considerably lower and remained at a constant level.

ORGAN DISTRIBUTION OF 65ZN IN EHRLICH ASCITES CANCER-BEARING MICE

Organ distribution of 65Zn injected i.p. or s.c. into Ehrlich ascites cancer-bearing mice was examined with the following results.1) Distribution of 65Zn injected i.p. was examined as a function of time (1-24 hr). 65Zn was found mainly in ascites cancer cells reaching a maximum (26%) 6 hr after the injection and its concentration was gradually decreased thereafter. Radioactivity of 65Zn in liver, kidney, pancreas and spleen were less than that in cancer cells. Disappearance of the radioactivity contained in cancer cells was very little after washing.2) Subcellular distribution pattern of 65Zn in ascites cancer cells was examined extending from 1 to 24 hr after i.p. injection. The amount of 65Zn in supernatant fraction was highest followed by nuclear, microsomal and mitochondrial fractions in the descending order and the above distribution pattern was same at any times.3) Radioactivity of 65Zn administered s.c. into cancer-bearing mice was significantly increased in the liver and decreased in pancreas and blood with no changes in the kidney and spleen compared with that in normal mice. After the i.p. injection of 65Zn into cancer-bearing mice, 66% of total radioactivity was found in ascites and 65Zn concentration in the liver, kidney, pancreas, spleen and blood were less than that in normal mice.4) When the radioactivity of 65Zn injected i.p. or s.c. in the subcellular fractions of liver and cancer cells are expressed per mg protein, the highest concentration of 65Zn in the liver was found in the supernatant fraction followed by microsomal, nuclear and mitochondrial fractions in the decending order. These distribution pattern of 65Zn was equal with that of cancer cells.5) 65Zn in the liver and cancer cells binds loosely with protein. After the treatment of each subcellular fractions obtained from liver and cancer cells with (NH4) 2SO4 (70% saturation) and trichloroacetic acid (10% in final), most of 65Zn was distributed in supernatant excepting the liver nuclear fraction in which most of radioactivity exists in precipitate by (NH4) 2SO4.6) Subcellular distribution of 65Zn in mammary carcinoma was examined 24 hr after the s. c. injection. 65Zn concentration is equal in nuclear and supernatnat fractions followed by microsomal and mitochondrial fractions in the descending order. The distribution pattern of 65Zn in nuclear fraction was different from that in the liver.

EFFECT OF VARIOUS DRUGS ON THE DISTRIBUTION OF 65ZN IN EHRLICH ASCITES CANCER-BEARING MICE

Various drugs (anti-cancer agents, chelating agents, amino acids and salts) were injected i.p. with 65Zn into Ehrlich ascites cancer-bearing mice, and after 1 hr its effect on the organ distribution of 65Zn was investigated.1. Mitomycin C (200 μgg/mouse), Toyomycin (50 μg/mouse) and Nitromin (500 μg/mouse) had no effects on the distribution of 65Zn. Merphyrin (500 μg/mouse) caused a decrease in 65Zn uptake by cancer cells without any effects in the other organs.2. EDTA and BAL (each 1 mg/mouse) inhibited 65Zn> uptake by cancer cells and conversely elevated its concentration in ascites supernatant. BAL elevated also 65Zn concentration in other various organs. Tetracycline, dihydrothioctic acid and Na-thioglycolic acid (each 1 mg/mouse) did not affect the 65Zn uptake by cancer cells.3. Penicillamine (D-and DL-type, each 1 mg/mouse) caused a decrease of 65Zn concentration in cancer cells with an increase of its concentration in the other organs. Cysteine, histidine and glycine (each 1 mg/mouse) had no effects on the 65Zn distribution in every organs.4. Various salts (each 0.1 ml of 3.5 ×10-2M solution was injected per mouse) also affected organ distribution of 65Zn. ZnSO4, CoCl2 and NiSO4 inhibited the uptake of 65Zn by cancer cells, however, MgCl2, MnSO4, FeCl<2 and CuSO4 had no effects on it. Organ distribution of 65Zn was also affected by various salts without definite relationship between them.5. In ascites cancer cells, the highest concentration of 65Zn was found in supernatant fraction, next in nuclear and microsomal fraction. The mitochondrial fraction contained the lowest amount. All of the above drugs had no effect on the intracellular distribution pattern of 65Zn in cancer cells.

Distribution of 65Zn 2+ in rat liver nuclei

1. 1. The distribution of 65Zn in rat liver nuclei has been studied in vivo and in vitro. 2. 2. A rapid and convenient method for isolating nucleoli is described. 3. 3. 65Zn distribution in the nucleoli is different in vivo and in vitro. 4. 4. Only EDTA inhibits the nuclear 65Zn uptake.

The uptake and distribution of 65Zn in oysters

Over a period of 6 weeks in aquaria, Portuguese oysters Crassostrea angulata, accumulate 65Zn to a greater extent than do native Ostrea edulis, although intake rates for any particular organ in either species are quite similar. The general distribution pattern of radioactivity in the tissues is similar to that observed for stable zine and 65Zn in other oyster species, concentration occurring to the greatest extent in gills and mantle, and least in muscle. The observed equilibrium concentrations and biological half-lives are considerably less than those measured in the natural environment, and the significance of this and its bearing on the mechanism of uptake is discussed. Cobalt and iron depress the rate of 65Zn uptake by both oyster soft tissues and the shell. The limiting effect in soft tissues is probably due to competition for sites at the actual point of uptake. The distribution of 65Zn in tissue subcellular fractions separated by centrifugation shows the greatest concentration of the radioisotope in the insoluble tissue components of gills, mantle and heart. Appreciable amounts of 65Zn are associated with tissue proteins.

Effects of Radiation on Zinc Metabolism of Sheep

SASSER, L. B., BELL, M. C., WADE, L., JR., AND JARBOE, G. E. Effects of Radiation on Zinc Metabolism in Sheep. Radiat. Res. 46, 115-128 (1971). Erythrocytes from 64 sheep given either a single gamma exposure to the whole body (240 R), a single beta dose to the skin (57 krads), an ingested dose of 90Y-labeled sand (2.4 mCi/kg body weight), or combinations of these three treatments were incubated with 65Zn and the percentage erythrocytic 65Zn uptake was determined. Concentrations of stable zinc in plasma and erythrocytes were also measured. In vitro uptake of 65Zn by erythrocytes of gastrointestinal and skin-irradiated sheep was higher than that of control sheep, but stable Zn content of erythrocytes was unaffected. Plasma Zn concentration was decreased (P < 0.05) by skin irradiation, but not by gastrointestinal or whole-body irradiation. Five skin-irradiated and two control sheep were intravenously dosed with 65Zn one year after irradiation and the turnover rate of Zn and tissue distribution of 65Zn were measured. The turnover rate of Zn in plasma was 4.8 mg/day per kilogram in skin-irradiated sheep and 6.9 mg/day per kilogram in control sheep. Urinary excretion of 65Zn by skin-irradiated sheep was increased, while fecal 65Zn was reduced the first day but unchanged over the total 10-day collection period. The injury produced by the radiation was probably responsible for the increased uptake of 65Zn by the erythrocytes rather than a direct effect of radiation to the erythrocyte or change in dietary Zn levels. The injury may have caused a shift of plasma proteins (a higher fraction of globulins) affecting the availability of Zn to the erythrocyte or caused

Effect of recent red leaf virus infection on the distribution of 65Zn, 45Ca, and 54Mn in subterranean clover

Subterranean clover (Trifolium subterraneurn L. cv. Yarloop) was grown in nutrient solutions which were supplied with 45Ca, 65Zn, or 54Mn either before (series A) or at the same time as (series B) the plants \+ere inoculated with subterranean clover red leaf virus (SCRLV) by means of the aphid vector Acyrthosiphon solani Kltb. SCRLV infection affected the distribution of each isotope, but less in series A than in series B plants. In both series, movement of the isotopes from the petiole (P) into the lamina (L) was retarded. In series B this resulted in a significant decrease in the concentration of 45Ca, 65Zn, or 54Mn in the lamina. The L/P ratios of concentration and the total contents of 65Zn and 54Mn in the leaves of SCRLV-infected plants from both series were also reduced. In addition SCRLV infection reduced the 54Mn concentration in the distal third more than in the remainder of the lamina. SCRLV infection increased the dry weight of the lamina and/or the LIP ratio of dry weight of the younger leaves of the series B plants.

Seasonal variation and distribution of 65Zn, 54Mn and 51Cr in tissues of the crab Cancer magister Dana.

Crabs were collected from the Columbia River estuary and their tissues were measured for both stable and radioactive Cr, Zn and Mn during 1966–67. Specific activities and radioactivities fluctuated throughout the year in much the same manner. Maximum radioactivities seem to be related to river discharge while peak specific activities may be due to metabolic changes in the crab. Chromium-51 and 65Zn accounted for nearly all of the gamma radioactivity in the tissues, 65Zn being mainly concentrated in soft tissues and 51Cr in hard tissues. Manganese-54 concentrations were highest in the setae and calcareous exoskeleton, presumably because of surface adsorbed 54MnO2. Chromium-51 concentrated in the setae, gills and hepatopanereas suggested that both surface adsorption and physiological processes are instrumental in its accumulation. Zinc-65 is noticeably concentrated in soft tissues probably because of its enzyme role in metabolism. Surface adsorption seems to play a minor role in the accumulation by crab tissues of this radionuclide. Specific activities suggest that surface adsorbed radionuclides are turned over faster than absorbed radionuclides.

Distribution of protein-bound zinc in normal and cirrhotic serum

The distribution of 65Zn among the serum proteins of 18 cirrhotic patients and 10 normal individuals was studied. Total zinc was measured in each serum. Zinc was bound to albumin, transferrin and α2-macroglobulin in all subjects. It was bound to IgG in all cirrhotics and five of ten normals. Utilizing the percentage distribution of 65Zn and total serum zinc, the amount bound in each fraction was calculated. Albumin-bound zinc correlated well with total serum zinc (r = 0.97). Total serum zinc was lower in cirrhotics than in normals (p < 0.01). The low serum zinc found in cirrhotics appears to be a function of serum albumin concentration. Zinc was consistently bound to transferrin and α2-macroglobulin. The total amount bound to these proteins (Tf-α2M) was of remarkably constant and equivalent size in normals and cirrhotics. Transferrin concentration was significantly lower (p < 0.01) in cirrhotics. The mean concentration of α2-macroglobulin was higher in cirrhotics although the difference was not significant (p < 0.10). There appears to be a reciprocal relationship between the amount of zinc bound to transferrin and that bound to α2-macroglobulin. However, the total amount bound to Tf-α2M remains remarkably constant even when total serum zinc falls as low as 12 μg./ml. The constancy of the amount of zinc bound to Tf-α2M implies metabolic control of this fraction. When serum zinc falls to very low levels, it may account for nearly one-half of the total serum zinc. It is suggested that transferrin and α2-macroglobulin may have an important role in internal zinc exchange. The distribution of 65Zn among the serum proteins of 18 cirrhotic patients and 10 normal individuals was studied. Total zinc was measured in each serum. Zinc was bound to albumin, transferrin and α2-macroglobulin in all subjects. It was bound to IgG in all cirrhotics and five of ten normals. Utilizing the percentage distribution of 65Zn and total serum zinc, the amount bound in each fraction was calculated. Albumin-bound zinc correlated well with total serum zinc (r = 0.97). Total serum zinc was lower in cirrhotics than in normals (p < 0.01). The low serum zinc found in cirrhotics appears to be a function of serum albumin concentration. Zinc was consistently bound to transferrin and α2-macroglobulin. The total amount bound to these proteins (Tf-α2M) was of remarkably constant and equivalent size in normals and cirrhotics. Transferrin concentration was significantly lower (p < 0.01) in cirrhotics. The mean concentration of α2-macroglobulin was higher in cirrhotics although the difference was not significant (p < 0.10). There appears to be a reciprocal relationship between the amount of zinc bound to transferrin and that bound to α2-macroglobulin. However, the total amount bound to Tf-α2M remains remarkably constant even when total serum zinc falls as low as 12 μg./ml. The constancy of the amount of zinc bound to Tf-α2M implies metabolic control of this fraction. When serum zinc falls to very low levels, it may account for nearly one-half of the total serum zinc. It is suggested that transferrin and α2-macroglobulin may have an important role in internal zinc exchange.

Incorporation of 65Zn in rat liver nuclei.

The intracellular distribution of 65Zn in rat liver has been studied in vivo and in vitro 1 The highest 65Zn uptake can be observed in the nuclear fraction. A maximum occurs after approx. 5 hours which is in contrast to the rapid rise of detectable 65Zn in the whole homogenate appearing immediately after the intraperitoneal injections of this metal ion. Further, 65Zn is retained by the nuclei for a much longer period. When Zn-deficient rats are employed 65Zn uptake is considerable enhanced at the beginning. However, the total 65Zn radioactivity of whole liver homogenate is only slightly increased. 2 The uptake of 65Zn by isolated liver nuclei suggests a strong temperature dependence in vitro. No 65Zn uptake at all can be measured when nuclei are employed which have been stored at –25° for two months. 3 An attempt has been made to isolate a double stranded DNA-65Zn complex from liver nuclei derived from 65Zn injected rats or from nuclei incubated with 65Zn. However, high ionic strength buffers or phenol displace 65Zn from the polynucleotide during the isolation procedure. 4 The intracellular 65Zn distribution in the liver portions remaining after partial hepatectomy in rats is in accordance with the results obtained above.

The Distribution of Zinc-65 inAgrostis tenuissibth. andA. stoloniferaL. Tissues4

The distribution of 65Zn in zinc-tolerant and copper-tolerant plants of Agrostis spp. from toxic mine-tailings in Enfland and Wales was compared with zinc distribution in non-tolerant plants. Isotope was applied in culture solution in which the plants were growing. No differences could be demonstrated between the plants were growing. No differences could be demonstrated between the plants by whole-plant radioautography, or by zinc analyses of the tops. Root/shoot ratios calculated from specific activity values varied with population, the non-tolerant plants having the lowest and the zinc-tolerant plants the highest ratio. After solvent (80 per cent ethanol and water) extractions, the root residue of zinc-tolerant plants contained a higher percentage of 65Zn than that of non-tolerant plants. Chemical fractionation of the roots revealed that the main high difference was that the amount of 65Zn in the pectate extract of the cell wall was high in zinc-tolerant plants and low in non-tolerant plants. The 65Zn distribution in the copper-tolerant plants was similar to that in the non-tolerant plants, indicating that the tolerance mechanisms for the elements are different. Soluble protein and RNA preparations were made but they contained low levels of 65Zn. An exception was the relatively high value for RNA from zinc-tolerant A. stolonifera shoots. An anionic complex of 65Zn in the soluble fraction was investigated. This complex accounted for most of the radioactivity in A. tennis extracts of shoots but the concentration of the complex was low in A. stolonifera shoots, and in root extracts of all plants examined.

Distribution of 65Zn In Tissues of Two Marine Crustaceans Determined by Autoradiography

In the benthic amphipod Anonyx sp., and the euphausiid Euphausia pacifica Hansen, 65Zn accumulated from seawater was shown by autoradiography to be localized predominantly in the exoskeleton and interstitial spaces of the myofibrils. Also, the gut and hepatopancreas of Anonyx sp. and the eye of E. pacifica contained 65Zn. The presence of 65Zn in crustacean exoskeletons may affect the efficiency of transfer of 65Zn through the food web and the vertical distribution of 65Zn in the Pacific Ocean along the Oregon coast.

The Distribution of Mineral Elements Following Leaf and Root Uptake

AbstractThe initial and subsequent distribution of 22Na, 43K, 86Rb, 134Cs, 32P, 35S, 45Ca, 65Zn and 85Sr in bean plants, following leaf and root uptake was studied under controlled environmental conditions. Autoradiographic and counting methods reveal vascular connections between leaves and roots and two patterns of distribution in the leaves following root uptake are reported. Distribution following treatment of specific parts of the leaves or roots points to a morphological unity in the bean plant. A possible circulation pattern for some ions is discussed.

Effects of Dietary EDTA and Cadmium on Absorption, Excretion and Retention of Orally Administered 65Zn in Various Tissues of Zinc-deficient and Normal Goats and Calves

The effects of dietary EDTA (300 ppm) and cadmium (350 ppm) on absorption, excretion and tissue distribution of 65Zn were determined following a single oral dosing in zinc-deficient and normal calves and goats. The feeding of EDTA had no significant effect upon fecal excretion or tissue distribution of 65Zn. However, there was a marked increase in urinary 65Zn excretion among the EDTA-fed animals which persisted throughout the experimental period. Dietary cadmium decreased absorption and tissue concentration of 65Zn. When 65Zn was calculated as percentage of absorbed dose most tissues of cadmium-fed animals contained amounts comparable to those of other animals. However, livers of cadmium-fed calves, but not goats, had more 65Zn as a percentage of absorbed dose than livers of other animals. Cadmium had little effect on urinary excretion of 65Zn. In general the effects of dietary EDTA and of cadmium in zinc-deficient animals were comparable to those in normal animals.

Absorption, Excretion, and Retention of Orally Administered Zinc-65 in Various Tissues of Zinc-deficient and Normal Goats and Calves

Absorption, excretion and tissue distribution of 65Zn was determined following oral dosing in zinc-deficient and normal calves and goats. In the livers, level of 65Zn was higher at 2 days than at later times. In some tissues, including hair, bone and muscle, the 65Zn concentration increased with time while in others the level reached a peak between 2 and 28 days after oral dosing. The tissues of the zinc-deficient animals held the 65Zn more tenaciously than those of the control animals. Fecal excretion of 65Zn reached a peak the third day after dosing and declined thereafter. 65Zn excretion via feces was higher for control than zinc-deficient animals. Apparent absorption was very high exceeding 80% for some treatments. These high absorption values are attributed to several factors including semipurified diets containing very low levels of zinc and are a reflection of mechanisms resulting in homeostatic conservation of the zinc.

Distribution of 65Zn in pear trees following bark injection

Two-year-old pear trees (cv. Packham Triumph) growing in 15-gal drums, were bark-injected with 65Zn 2 months after bud burst. To some injection doses nonradioactive zinc with or without EDTA was also added. The 65Zn only moved from the injection point when extra zinc was included in the dose. EDTA further enhanced this movement. The 65Zn was distributed to spurs and laterals on the injected leader, situated above and on the same side as the point of injection. Limited downward movement was also evident. 65Zn was detected in new growth formed after injection, and also in blossom, leaves, and new lateral growth produced on the injected leaders in the following season. It was found that 65Zn accumulated at the nodes on laterals, and in the petioles, midrib, and major veins of the leaves.