Epidemiologic investigation of lead poisoning in trumpeter and tundra swans in Washington State, USA, 2000-2002

An observational study was conducted to determine the proportionate mortality of wild trumpeter (Cygnus buccinator) and tundra (Cygnus columbianus columbianus) swans that died during the winters of 2000-02 in northwestern Washington State, USA. Among 400 swans necropsied, 81% were lead poisoned (302/365 trumpeter swans; 20/35 tundra swans). Mortality started in mid-November and peaked from late December through mid-February; swan mortality that was not associated with lead poisoning was uniformly lower throughout the winter months. Lead poisoning was 24 times more likely to be the cause of death in swans found in Whatcom County compared to swans found in other locations in northwestern Washington State (95% CI: 12.7, 47.0). Mortality attributable to lead poisoning was twice as likely in adults as in juveniles (95% CI: 1.0, 4.2). Aspergillosis was documented in 62 trumpeter and two tundra swans, including 37 swans in which mortality was caused by lead poisoning. Males were twice as likely as females to have aspergillosis (95% CI: 1.1, 3.8). Traumatic injuries were documented in 37 trumpeter and seven tundra swans, including seven trumpeter swans with concurrent lead poisoning. Dead swans found outside Whatcom County were four times more likely to have traumatic injuries compared to those found in Whatcom County (95% CI: 1.6, 10.0). Overall, lead-poisoned swans were significantly less likely to have concurrent aspergillosis or traumatic injuries. There was no apparent association between grit ingestion (total mass or mass categorized by size) and lead poisoning or number of lead shot. Not surprisingly, lead-poisoned swans were more likely to have one or more lead shot compared to swans that died from other causes (OR 294; 95% CI: 92, 1,005); lead-poisoned swans were also more likely to have one or more nontoxic shot compared to swans that were not poisoned (OR 63; 95% CI: 19, 318). The source(s) of shot are unknown but likely are in or near Whatcom County, Washington.     

Evidence of Alaskan Trumpeter Swan Population Growth Using Bayesian Hierarchical Models

ABSTRACT Alaska (USA) contains a large proportion of the breeding population of trumpeter swans (Cygnus buccinator) in the United States. However, tracking population trends in Alaska trumpeter swans is complicated by variables such as an increase in survey effort over time, periodic surveys (1968 and every 5 yr after 1975), and missing data. We therefore constructed Bayesian hierarchical negative binomial models to account for nuisance variables and to estimate population size of trumpeter swans using aerial survey data from all known breeding habitats in Alaska, 1968–2005. We also performed an augmented analysis, where we entered zeroes for missing data. This approach differed from the standard (nonaugmented) analysis where we generated estimates for missing data through simulation. We estimated that adult swan populations in Alaska increased at an average rate of 5.9% annually (95% credibility interval = 5.2–6.6%) and cygnet production increased at 5.3% annually (95% credibility interval = 2.2–8.0%). We also found evidence that cygnet production exhibited higher rates of increase at higher latitudes in later years, which may be a response to warmer spring temperatures. Augmented analyses always produced higher swan population estimates than the nonaugmented estimates and likely overestimate true population abundance. Our results provide evidence that trumpeter swan populations are increasing in Alaska, especially at northern latitudes. Changes in population size and distribution could negatively affect tundra swans (Cygnus columbianus) breeding in Alaska, and biologists should monitor these interactions. We recommend using nonaugmented Bayesian hierarchical analyses to estimate wildlife populations when missing survey data occur.     

Effect of cis-diamminedichloroplatinum (II) on metallothionein induction and trace element metabolism in rats fed different amounts of dietary zinc

Recent studies have suggested that the induction of metallothionein synthesis in kidneys of mice by the acute administration of bismuth and other trace elements might protect against cis-diamminedichloroplatinum (II) nephrotoxicity. The present study was designed to determine the effects of dietary zinc and cis-diamminedichloroplatinum (II) on the induction of liver and kidney metallothionein and its subsequent effect on nephrotoxicity and trace element metabolism in rats. Male rats were fed diets containing 5, 20, 80, or 320 mg zinc/kg diet for 3 weeks. Each dietary group was subdivided into 3 groups. In one group, each rat received an i.p. injection of 7.5 mg cis-diamminedichloroplatinum (II)/kg b.w. All other rats received saline. During the next three days a second group of rats was pair-fed to the cis-diamminedichloroplatinum (II) injected group. A third group received no treatment and was allowed to eat ad libitum. Results showed that when dietary zinc was increased from 5 mg/kg diet to higher amounts, kidney metallothionein concentration increased twofold. cis-diamminedichloroplatinum (II) treatment increased kidney metallothionein even further, but elevated metallothionein gave no protection from the toxic effects of the drug. Serum copper concentration and ceruloplasmin activity were significantly lower with higher concentrations of dietary zinc, which indicated that these rats were mildly copper-deficient. There was a small but significant depression of superoxide dismutase activity and a highly significant increase in thiobarbituric acid reactive substances in kidneys of rats treated with cis-diamminedichloroplatinum (II) compared to either pair-fed or ad libitum controls. This supports the hypothesis that part of the mechanism for cis-diamminedichloroplatinum (II)-induced toxicity might be caused by free-radical generation. However, the data do not support the hypothesis that metallothionein induction protects the kidney from cis-diamminedichloroplatinum (II) toxicity.     

Histidine protects against zinc and nickel toxicity in Caenorhabditis elegans

Zinc is an essential trace element involved in a wide range of biological processes and human diseases. Zinc excess is deleterious, and animals require mechanisms to protect against zinc toxicity. To identify genes that modulate zinc tolerance, we performed a forward genetic screen for Caenorhabditis elegans mutants that were resistant to zinc toxicity. Here we demonstrate that mutations of the C. elegans histidine ammonia lyase (haly-1) gene promote zinc tolerance. C. elegans haly-1 encodes a protein that is homologous to vertebrate HAL, an enzyme that converts histidine to urocanic acid. haly-1 mutant animals displayed elevated levels of histidine, indicating that C. elegans HALY-1 protein is an enzyme involved in histidine catabolism. These results suggest the model that elevated histidine chelates zinc and thereby reduces zinc toxicity. Supporting this hypothesis, we demonstrated that dietary histidine promotes zinc tolerance. Nickel is another metal that binds histidine with high affinity. We demonstrated that haly-1 mutant animals are resistant to nickel toxicity and dietary histidine promotes nickel tolerance in wild-type animals. These studies identify a novel role for haly-1 and histidine in zinc metabolism and may be relevant for other animals.     

土壤中镉、铅、锌及其相互作用对作物的影响

通过作物盆栽模拟试验(砂壤质褐土、pH值8.2)揭示：土壤中分别施入镉(CdCl2)、铅[Pb(CH3COO)2]或锌(ZnSO4)其影响表现为,植物各器官镉的含量超过对照植物的数倍至500倍。土壤镉浓度<5ppm和<10ppm分别造成某些蔬菜和水稻的污染。铅主要积累在植物根部,土壤铅污染对作物的影响较小。锌主要积累在植物叶片和根部,对水稻产生生长抑制的土壤锌浓度临界值不大于200ppm,此浓度对旱作无影响。土壤中同时施入镉和铅,植物对镉的吸收增加。而土壤中镉的增加却减少了植物体内铅的含量。土壤中由于镉、锌或铅、锌相互作用的结果,水稻对它们的吸收都有增加。在旱地土壤锌浓度的增高,降低了植物对镉、铅的吸收。镉、铅、锌同时施入土壤由于相互作用的结果,除锌之外,植物对镉、铅的吸收有明显下降。评价土壤重金属污染,不仅要看它们的含量及其存在形态,而且要分析它们之间的相互作用(促进或拮抗)特点。     

Characterization of microsatellite loci isolated in trumpeter swan (Cygnus buccinator)

Primers for 16 microsatellite loci were developed for the trumpeter swan (Cygnus buccinator), a species recovering from a recent population bottleneck. In a screen of 158 individuals, the 16 loci were found to have levels of variability ranging from two to seven alleles. No loci were found to be linked, although two loci repeatedly revealed significant departures from Hardy–Weinberg equilibrium. Amplification in the closely related tundra swan (Cygnus columbianus) was successful for all except one locus. These microsatellite loci will be applicable for population genetic analyses and ultimately aid in management efforts.     

Antidiabetic and Pancreas-Protective Effects of Zinc Threoninate Chelate in Diabetic Rats may be Associated with its Antioxidative Stress Ability

Zinc exerts a wide range of important biological roles. The present study was carried out to investigate the effects of zinc threoninate chelate in blood glucose levels, lipid peroxidation, activities of antioxidant defense systems and nitrite concentration, and histology of the pancreas in diabetic rats. Wistar rats were intravenously injected with a single dose of streptozotocin to induce diabetes. Then, diabetic rats were administrated orally with zinc threoninate chelate (3, 6, and 9 mg/kg body weight) once daily for 7 weeks. Fasting blood glucose was monitored weekly. At the end of the experimental period, the diabetic rats were killed, and levels of serum insulin, malondialdehyde, and nitric oxide, activities of glutathione peroxidase, total superoxide dismutase, copper/zinc-superoxide dismutase, and nitric oxide synthase were determined; pancreas was examined histopathologically as well. Zinc threoninate chelate significantly reduced the blood glucose levels and significantly increased the serum insulin levels in diabetic rats. In addition, zinc threoninate chelate caused a significant increase in activities of antioxidant enzymes and significant decrease in nitrite concentration and malondialdehyde formation in the pancreas and serum of diabetic rats. These biochemical observations were supplemented by histopathological examination of the pancreas. These results suggested that the antidiabetic effect of zinc threoninate chelate may be related to its antioxidative stress ability in diabetic rats.     

Morphofunctional analysis of zinc-accumulating capacity of digestive system organs]

The distribution of zinc and related changes have been studied in zinc--loaded chick pancreas, ileum and liver at the ultrastructural level by sulphide--silver method. White Leghorn chicks fed a high zinc diets (50, 500, 1000, 2000 and 4000 mgZn/kg diet) for 6 weeks, were killed at intervals; portions of their organs were fixed for light and electron microscopy; other samples were analyzed for zinc by AA spectrophotometry. A drastic increase of zinc level in chick pancreas fed 2000 mg Zn/kg diet (as ZnCl2) was associated with acinar cell degeneration. Apoptosis was the predominant form of acinar cell deletion. This study provides support for a previously proposed theory that cell injury stimulates passive zinc accumulation.     

Effects of ingestion of cadmium-polluted rice or low-dose cadmium-supplemented diet on the endogenous metal balance in female rats

The concentrations of endogenous metal ions in liver, kidney, and bone tissues of female rats were measured after ingestion of cadmium-polluted rice (1.24 ppm as Cd) or cadmium-supplemented rice (1.24 and 4.96 ppm) for 2 or 4 mo. The metal accumulated mainly in the kidneys and in the liver. The concentration of cadmium (Cd) in the kidneys of rats fed a 1.24-ppm Cd-supplemented diet was significantly higher than in the Cd-polluted rice group. After 2 mo, the levels of iron and sodium in the liver were elevated in the Cd-polluted rice group, but not in the 1.24-ppm Cd-supplemented group, as compared to controls. The zinc concentration in the Cd-polluted rice group was decreased. The concentration of copper in the kidneys was increased for all Cd-containing diet groups. After 4 mo, the effects of Cd on essential metals in the Cd-polluted and 1.24-ppm Cd-supplemented groups had almost disappeared, although several metal ions in selected organs in the 4.96-ppm Cd-supplemented group showed more prominent changes than in the group exposed for 2 mo. These results suggest that the effects of short-term exposure to Cd on essential metal balance are stronger for rice-bound Cd than for inorganic Cd, although the absorption rate of Cd in Cd-polluted rice may be lower than that of cadmium chloride added to rice.     

Abnormal glucose metabolism in murine cytomegalovirus (MCMV)-infected mice

Five strains of male and female mice were infected with salivary gland-passaged murine cytomegalovirus (SG-MCMV) intraperitoneally. Although none of them became hyperglycemic, 13-30% of BALB/c male and female, ICR/Slc male and female and C57BL/6J male mice had abnormal values in glucose tolerance tests (GTT) 14 to 30 day post infection. Serum insulin levels in BALB/c male mice were low and infective virus was detected in the pancreas during the acute phase of infection. Histopathology showed mild edematous changes with inflammatory cell infiltrations in the pancreas. Viral antigen was located in acinar cells and occasionally in beta cells by an immunofluorescence test.     

The effect of heavy metal accumulation on metallothionein content in selected tissues of bank voles and yellow-necked mice caught near a steelworks and zinc smelter

The effect of cadmium, zinc, and copper accumulation on metallothionein content in the selected tissues of bank voles and yellow-necked mice trapped near the Sendzimir Steelworks in Krakow and the zinc smelter in Bukowno were analysed. The Borecka Forest was chosen as a control area. The highest cadmium concentration, 32.98 microg g(-1) dry weight, was detected in the kidneys of the bank voles caught in the Bukowno area. Zinc and copper concentrations in the tissues did not exceed the critical values. Metallothionein content in the liver and kidneys was associated with heavy metal accumulation in the tissues. The highest content of sulphydryl groups was detected in the livers of the bank voles trapped within the neighbourhood of the zinc smelter in Bukowno. The highest level of disulphide bonds was found in the kidneys of the bank voles from the same area.     

Elastase-1-secreting acinar cell carcinoma of the pancreas. A cytologic, electron microscopic and histochemical study

A case of acinar cell carcinoma of the pancreas was diagnosed by fine needle aspiration cytology during surgery. The cytologic characteristics of this neoplasm are described. Electron microscopy disclosed numerous zymogen granules in the tumor while histochemistry demonstrated the presence of elastase-1. Serum elastase-1 levels were markedly elevated. The cytologic differential diagnosis of pancreatic tumors is discussed.     

Autometallography allows ultrastructural monitoring of zinc in the endocrine pancreas

Zinc is intimately involved in insulin metabolism, its major known role being the binding of insulin in osmotically stable hexamers in beta-cell granules. To investigate the anatomical distribution of zinc ions necessary for insulin binding we examined the rat pancreas by autometallography (AMG). AMG demonstrates chelatable zinc and is a sensitive marker for zinc in vesicles and also a surrogate marker for recently described zinc pumps regulating intravesicular zinc metabolism. Zinc ions were found in alpha- and beta-cell granules, primarily in the periphery of the granules. Only occasionally was zinc seen in other islet cell types. AMG allows the study of the microscopic and ultrastructural localisation of free zinc ions in the pancreas. The applicability of the method at the ultrastructural level in particular makes AMG a very sensitive tool in future studies on the role of zinc ions in the pancreas.     

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.     

Effect of zinc on the toxicity of the mycotoxin sporidesmin to the rat

The toxicity of sporidesmin to rats fed diets containing either 4 ppm or 200 ppm Zn was determined. The high zinc diet doubled the LD₅₀ level for sporidesmin given as a single dose, but the LD₅₀ dose for rats on a zinc deficient diet was not significantly different from that for rats on a diet containing zinc at levels sufficient for normal growth. Subsequent trials demonstrated that large doses of ZnSO₄ given orally protected rats from sporidesmin poisoning. The protection was short lived as zinc needed to be given at or soon after sporidesmin challenge.     

Influence of Copper,Iron, Zinc and Fe<Stack><Subscript>3</Subscript><Superscript>+</Superscript></Stack> Haemoglobin Levels on the Etiopathogenesis of Chronic Calcific Pancreatitis—A Study in Patients with Pancreatitis

Chronic pancreatitis is a serious condition associated with severe abdominal pain, and a significant percentage of patients progresses to irreversible calcification in pancreas. The present study evaluates the degree to which the levels of trace elements, copper, iron, selenium, zinc and haemoglobin-Fe³⁺, in blood, serum and pancreas have any role to play in the calcification process associated with fibrosis in pancreas. Twenty-seven calcific (CCP) and 23 non-calcific chronic pancreatitis (CP) patients and equal number of age- and sex-matched normal volunteers (50) were enrolled in the study. Surgically removed pancreatic tissue and blood samples were analysed for copper, iron, selenium, zinc, protein, collagen and lipid peroxidation products in terms of malondialdehyde, protein carbonyls, glutathione, methemoglobin, methemoglobin reductase and ceruloplasmin activity levels. We could find that the pancreatic tissue levels of copper, iron, protein and collagen contents were significantly elevated in CCP patients when compared to CP patients. Serum levels of copper, free ionic copper and iron were also elevated in CCP patients. The serum and the pancreatic tissue level of zinc and selenium showed a significant decrease in CCP patients. The level of methemoglobin was elevated more significantly with the concomitant decline in the activity of methemoglobin reductase. There was a positive correlation between the pancreatic level of copper and iron with the collagen and protein levels. The results of the present study revealed that the levels of copper and iron, the pro-oxidants and zinc and selenium may influence calcification process in CCP patients. Hypoxia-related tissue injury due to the formation of oxidised haemoglobin may also contribute to the pathogenesis of calcification in pancreas.     

Studies on the role of iron in zinc toxicity in chicks

The interaction of dietary iron and zinc was studied in chicks. Zinc was found to be more toxic in iron-deficient animals than iron-supplemented animals as measured by hemoglobin concentrations and growth. Analyses of the kidney and liver for iron and zinc were carried out. As the level of iron was increased from 0-1000 ppm supplementation, the concentration of liver zinc increased. The organ levels of iron were decreased as the dietary zinc levels were increased from 0-5000 ppm. Radioisotope studies using⁶⁵Zn revealed that the iron content of the diet did not affect absorption of zinc. Administration of the isotope, either in an intestinal segment or intravenously, resulted in more zinc being taken up by the liver in the iron supplemented animals. This was especially noted when the ratio of the isotope in liver to that in the blood was compared. Gel chromatography of kidney and liver homogenates revealed that iron deficiency resulted in less zinc being eluted in a volume characteristic of metallothionein compared to homogenates of organs from iron supplemented animals. The results indicate that iron-supplemented animals have a greater capacity for sequestering zinc on metallothionein than do iron-deficient animals. Conversely, iron-deficient chicks were more susceptible to the effects of zinc toxicity than are iron-adequate chicks.     

Parenteral zinc and tissue metallothionein in normal and diabetic rats

The effect of parenteral zinc on tissue metallothionein (MT) was studied in normal and streptozotocin-induced diabetic rats. The accumulation of Zn-MT in liver and pancreas of normal and diabetic rats following the administration (ip) of various amounts of zinc was not different. Renal Zn-MT was higher in the diabetic group, and this was not changed by zinc injection. Although diabetic rats, relative to normal, possessed a markedly higher concentration of Cu-MT in kidney initially, this difference decreased considerably after zinc injection. The ratio of Cu-MT to cytosolic Cu in kidney was not affected by parenteral zinc and was highest in diabetic rats. Zinc injection markedly reduced food intake, water consumption, and urine output in both normal and diabetic rats. Blood glucose of diabetic rats also decreased 24 h after zinc administration. Our results indicate that relative to normal, MT and zinc metabolism are different in kidney, and to some extent liver, but not different in the pancreas of the chemically induced diabetic rat.     

A comparison of raw starch-digesting glucoamylase production in liquid and solid cultures of Rhizopus strains

Maximum growth for Rhizopus sp. A-11 was obtained at a zinc ion concentration of 0.7 ppm in a liquid medium. Glucoamylase (GA, EC 3.2.1.3) production in Rhizopus sp. A-11 was maximized at 710 U/ml, at the presence of 75 ppm for calcium and 0.7 ppm of zinc ions in liquid medium. Zinc ion is known as an essential biometal for Rhizopus growth; however, growth was inhibited by the zinc ion concentration, not maximized. Although calcium ion was not necessary to Rhizopus growth, GA production using Rhizopus sp. A-11 was markedly stimulated by calcium ion concentration over 75 ppm in the liquid medium. The GA productivity of the present liquid culture was about 4.4 times higher than that of the solid state culture, based on the unit starch amount in the liquid and solid media carbon source. The characteristics of the GA produced by the Rhizopus sp. A-11 liquid culture were interesting; that is, almost all the GA produced was classified as raw starch-digesting GA (GA-I). Secreted protein in the culture liquid after 30 h was nearly GA, and had a limited amount of impure protein. As a result, it was found that using a Rhizopus culture in a specified metal-ion regulated medium was an effective method for producing GA. Thus the present culture method was renamed the "metal-ion-regulated liquid culture method".     

Zinc in Thalassemic Patients and Its Relation with Depression

Studies have shown that there is a relationship between zinc levels and depression. Thalassemic patients are at risk of zinc deficiency due to various causes including Desferal injection. The aim of this study, therefore, is to investigate hair zinc levels in thalassemic patients and their association with depression. For the purposes of this survey, 50 patients with major thalassemia between 10-20 years old were selected randomly. The patients' hair zinc concentration was compared with a control group of similarly aged healthy individuals. Simultaneously, their psychological status was evaluated with either the "Beck" or "Marya Kovacs" test (according to age) so that the relation between depression and zinc concentration could be assessed. The mean hair zinc concentration in patients was more than the controls (193.96 +/- 92.4 ppm vs 149.6 +/- 72.21 ppm). Zinc deficiency was present in 10% of the patients, and 52% had some degree of depression. There was a reverse correlation between zinc deficiency and blood transfusion rate (p < 0.05). Also, while there were more incidences of depression among the zinc deficient patients, the difference was not significant. Regarding the high prevalence of depression and insignificant relation to the zinc deficiency in these thalassemic patients, this research suggests the need for further consideration concerning patients' psychological status, the risk factors of zinc deficiency, as well as extended assessment into other causes of depression.