Silver in liver

At day 43, the 3000 mg/kg diet had 4 times more 51 silver in livers than did controls however, there was no significant elevation in silver burdens of kidneys, gills or intestine. Daily food consumption rates were lowered by 14-22% in groups receiving 30 mg Ag/kg ration and higher, possibly because of decreased palatability of the silver-laden diets. 

Silver concentrations in muscle of Antarctic birds were low (0.01 mg/kg DW) when compared to livers (0.02 to 0.46 mg/kg DW) or feces (0.18 mg/kg DW Szefer et al. 1993). Silver concentrations in avian tissues, especially in livers, were elevated in the vicinity of metals-contaminated areas and in diving ducks from the San Francisco Bay (Table 7.5). Birds with elevated concentrations of silver in tissues — as much as 44 mg/kg DW in liver in the common eider (Somateria mollissima) — seemed outwardly unaffected (Bryan and Langston 1992). 

About 3% (0.8 jg) of the deposited silver was 1 found in liver and blood 6h after exposure. Clearance from the lung to the blood was triphasic, with half-times of 1.7, 8.4, and 40 days... 

Intraperitoneal injection route 20 mg/kg BW, single injection All dead within 2 h. Silver granules in liver parenchyma and kidney tubules 3... 

USEPA 1980). The biological half-time of silver in the lungs of an exposed person was about 1 day in liver it was 52 days (Fowler and Nordberg 1986). In humans, 80% of the retained silver in lung was cleared in about 1 day 50% of the remainder was usually cleared in 3 days (USEPA 1980). In persons who had accidentally inhaled radiosilver-llOm, most of the inhaled silver had a half-time persistence of about 1 day, probably because of rapid mucociliary clearance, swallowing, and fecal excretion most of the absorbed radiosilver translocated to the Uver (USEPA 1980). 

Whole body BCF during immersion rose rapidly and 27 progressively to 51 at day 19, then more slowly to 73 at day 41. At day 41, BCF tor liver was 866, for digestive tract 560, tor kidneys 299, tor spleen 155, and for air bladder 109. During depuration, 68% of the silver was eliminated — about 31% during the first 3 days and 37% in the next 39 days. In both uptake and depuration phases, 71-77% of all radiosilver was present in liver and digestive tract... 

After 6 h, 96.9% remained in the lung, 2.4% in liver, 0.35% in blood, 0.14% in gall bladder and bile, 0.1% in intestines, 0.06% in kidneys, and 0.02% in stomach. After 225 days, 0.49% of the initial dose was detected in liver, and 0.01-0.03% each in brain, gall bladder, intestines, lungs and trachea, bone, stomach and contents, heart, and muscle. If lung is excluded, liver contained 77% of the total silver body burden between 6 h and 225 days postexposure... 

A study in dogs indicates that absorption of inhaled metallic silver particles with a median aerodynamic diameter of approximately 0.5 pm is extensive, and is not dependent upon particle size (Phalen and Morrow 1973). Absorption was measured in one dog that remained anesthetized during the entire period between exposure and sacrifice. In this dog, 3.1% (0.8 pg) of the deposited material was dissolved, transported out of the lungs, and was found mostly in liver and blood 6 hours after exposure a 1 pg/cm /day absorption rate for metallic silver was estimated by the authors. Up to 90% of the deposited silver was estimated to be absorbed into the systemic circulation based on all experimental data. Clearance from the lung to the blood was triphasic, with half-lives of 1.7, 8.4, and 40 days. 

Limited information was located concerning the distribution of silver in humans following inhalation of elemental silver or silver compounds. Using whole-body spectrometer measurements obtained from a person accidently exposed to radiolabeled silver, Newton and Holmes (1966) estimated that 25% of the detectable mAg was distributed to the liver between 2 and 6 days after exposure. 

Following the topical application of silver nitrate for the treatment of burns in two humans, silver was distributed to the muscles (0.03-2.3 ppm), liver (0.44 ppm), spleen (0.23 ppm), kidney (0.14 ppm), heart (0.032-0.04 ppm), and bones (0.025 ppm) (Bader 1966). No studies were located that quantitated the distribution of silver in animals following dermal exposure to silver or its compounds. However, Sano et al. (1982) detected silver in the same tissues of rats following topical application of silver sulphadiazine cream. 

Silver removal from the liver by biliary excretion was demonstrated by Scott and Flamilton (1950). Control rats and rats with ligated bile ducts were administered radioactive metallic silver by intramuscular injection. In rats with ligated bile ducts, excretion of silver in the feces was 19%, compared to 97% in controls. Deposition in the liver of rats with ligated bile ducts was 48% and 2.5% in the gastrointestinal tract compared to 0.36% and 1.12%, respectively in the controls (Scott and Flamilton 1950). Klaassen (1979b) determined that biliary excretion accounted for between 24% and 45% of the silver administered to rats. The concentration of silver in the bile was estimated to be... 

Developmental Effects. Based on the existing information, it is not known whether silver causes developmental toxicity in humans. No studies were found concerning developmental effects in humans after exposure to silver. However, a human study by Robkin et al. (1973) did investigate the possibility of a relationship between the concentration of this heavy metal in the tissue of fetuses and the occurrence of developmental abnormalities. These authors reported that the concentration of silver in the fetal liver of 12 anencephalic human fetuses was higher (0.75 0.15 mg/kg) than the values from 12 fetuses obtained either through therapeutic abortions (0.23 0.05 mg/kg), or in 14 spontaneously aborted fetuses (0.21 0.05 mg/kg). The concentration in 9 premature infants was 0.68 0.22 mg/kg. The authors could not determine if the higher concentrations of silver in anencephalic fetuses were associated with the malformation, or with fetal age. 

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