Maja Lazarus

Institute for Medical Research and Occupational Health · Analytical Toxicology and Mineral Metabolism Unit

Vultures are long-lived large raptors whose feeding on carcasses of large and medium-sized mammals exposes them often to lead (Pb) from spent ammunition. In addition to pesticides and non-steroidal anti-inflammatory drugs, Pb is the most frequent anthropogenic chemical reported to cause death and disease in free-living vultures in the world. Specif...

Terrestrial top carnivores are susceptible to renal and hepatic accumulation of persistent inorganic pollutants due to their trophic position. Toxic potential of metal(loid)s taken up by prey consumption carries the risk of adverse effects for exposed predator. Eurasian lynx (Lynx lynx) and European wildcat (Felis silvestris silvestris) are strictl...

Environmental contaminants like arsenic (As), cadmium (Cd), mercury (Hg) or lead (Pb) may disrupt hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes due to their endocrine toxicity potential. Resulting long-term physiological stress or adverse effects on wildlife reproduction and ontogeny may cause detrimental effect...

High temperature (HT) causes physiological and biochemical changes in plants, which may influence their nutritional potential. This study aimed to evaluate the nutritional value of broccoli seedlings grown at HT on the level of phytochemicals, macro-and microelements, antioxidant capacity, and their extracts' in vitro cytotoxicity. Total phenols, s...

Trace element pollution can adversely affect the brains of individuals and thus impact the entire population of apex predators, such as large European carnivores. We assessed exposure to prominent neurotoxicants As, Cd, Hg and Pb by measuring their brain stem levels in brown bears (n = 114), grey wolves (n = 8), Eurasian lynx (n = 3), and golden ja...

The aim of this study was to investigate the temporal trends and geographical differences in 90Sr and stable element (Ba, Ca, Mn, Sr, Pb, Zn) levels in the bones of Croatian and Polish brown bear (Ursus arctos) populations. Experimental data suggest that in the decades after nuclear weapon tests and the Chernobyl accident, 90Sr bone activity concen...

Himalayan balsam (Impatiens glandulifera Royle) is an invasive garden ornamental plant species originating from Asia, which produce significant amounts of nectar. In Croatia, it is widely dis-tributed along the banks of the Mura River. Although this plant species is widespread in Europe there are still no available scientific data about this uniflo...

The natural gas industry bears a certain contamination risk to human and biota due to, among others, mercury, arsenic, and naturally occurring radioactive material content in gas. We tracked multiple stabile metal(loid)s and radionuclides within the natural gas treatment plant Molve, Croatia, ecosystem during the last decade through a comprehensive...

Maternal cigarette smoking may impair the pro/antioxidant balance, affect bodily element disposition and disturb nutrient and oxygen transport to the developing foetus. The aim of this study was to assess the effect of active maternal smoking during pregnancy on superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and metallothion...

Lead as an ubiquitous environmental pollutant of natural and anthropogenic origin enters a bear’s organism mostly via food and water. It is initially found in the bloodstream bound to red blood cells and reflects recent exposure. As a non-essential metal, lead causes adverse health effects on a developing nervous system (maternal transfer), renal,...

Honey is a nutritionally valuable natural product of honey bees which can be contaminated by anthropogenic chemicals from the surrounding environment and beekeeper practices. Good beekeeping practice in conventional and regulations on organic beekeeping aim to reduce harmful residues in honey for human consumption. We compared prominent metal(loid)...

Maternal cigarette smoking may impair the pro/antioxidant balance, affect bodily element disposition and disturb nutrient and oxygen transport to the developing foetus. The aim of this study was to assess the effect of active maternal smoking during pregnancy on superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and metallothion...

The confirmation of honey authenticity is an ongoing challenge. We investigated new authenticity markers (13 macro and trace elements, total phenolic (TP) content, antioxidant capacity) in 62 unifloral and multifloral honeys from Croatia as loadings for principal component analysis (PCA), taking into account the spatial, temporal and production pra...

Quality and safety of food, including honey, is one of the leading priorities regarding residues of anthropogenic chemicals with proven adverse health effects. In total, 61 honey samples of known botanical origin were collected in period 2018-2019 from Croatian registered organic and conventional beekeepers (N=16 organic and N=45 conventional honey...

The effect of maternal smoking as a source of exposure to toxic metals Cd and Pb on superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, metallothionein (MT), Cd, Pb, Cu, Fe, Mn, Se and Zn concentrations were assessed in maternal and umbilical cord blood and placenta in 74 healthy mother-newborn pairs after term delivery. Sparse di...

We investigated the level of five non-essential metal(loid)s (As, Cd, Hg, Tl, Pb) and nine essential metals (Mg, Ca, Mn, Fe, Co, Cu, Zn, Se, Mo) in hair and blood components of captive and free-ranging European brown bear populations in Croatia and Poland. Metal(loid) associations with biomarkers of oxidative stress (superoxide dismutase, SOD; glut...

Muscle, liver and kidney of 21 Barbary sheep (Ammotragus lervia) from Mosor Mountain, Croatia, were sampled to quantify the activity of caesium and potassium radionuclides, five toxic and ten essential stabile elements in order to establish reference values for this species and to evaluate the potential of Barbary sheep tissues to reflect environme...

Main sources of cadmium exposure in general population are food, water, and tobacco smoke. Cadmium absorption after respiratory (parenteral) exposure is on avg. 5-10 times higher than after gastrointestinal absorption. The latter increases 2-3 times during gestation in rats. Cadmium accumulates in internal organs, including the placenta, and intera...

In recent years cadmium has been recognized of having potency to act as metalloestrogen in mammals. We investigated earlier effects of parenteral exposure to cadmium (total dose 5 mg Cd/kg s.c.) in pregnant rats and found that it caused perturbations in element concentrations in maternal and foetal compartments, serum oestradiol concentration, and...

We explored the long-term accumulation of aluminum, strontium, cadmium and lead in the compact and trabecular bone of the femoral epiphysis, metaphysis and diaphysis in 41 brown bears (Ursus arctos) from Croatia. Also, we assessed their influence on macro and trace elements (sodium, magnesium, phosphorus, potassium, calcium, manganese, iron, cobalt...

Distribution of environmental lead in brown bear body compartments

The influence of reproductive and (early) life stages on toxic metal levels was investigated in the brown bear (Ursus arctos), the largest mammalian predator species in Croatia. The purpose was to examine critical clusters in a population that might be at a higher risk of adverse health effects caused by metals as environmental contaminants. Levels...

The aim of the study was to determine the effects of supplementary dietary organic selenium on oxidative stability and quality of cooled and deep-frozen chicken breast and thigh muscles. The research was undertaken on broilers Cobb 500 subdivided to three randomly assigned groups: inorgSe0.3 (sodium selenite added to feed at 0.3 mg·kg-1), orgSe0.3...

Tissue element investigations of apex terrestrial mammals are very scarce in Europe. We quantified 16 essential and non-essential elements in the kidney cortex, liver and muscle tissue of 467 brown bears (Ursus arctos), 125 grey wolves (Canis lupus), one Eurasian lynx (Lynx lynx) and three golden jackals (Canis aureus) from Croatia by inductively c...

The concentration of 23 major and trace elements, total phenolic content (TPC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were determined in nine samples of strawberry tree honey and compared to other types of unifloral honeys. The most abundant elements in strawberry tree honey were potassium, calcium, magnesium and sodiu...

The European brown bear (Ursus arctos L.) is the largest terrestrial mammal in Croatia. Although known as omnivorous species, almost 95% of the brown bear's diet in Croatia consists of plants. Maize is the important part of bear's diet due to its availability at supplemental feeding sites and the bear's opportunistic feeding habits. This supplement...

Levels of elements in brown bear (Ursus arctos) blood are unknown. Previously, we discovered that brown bears in Croatia have the highest tissue levels of toxic metals among hunted terrestrial wild mammals. However, associations with other related biomarkers of exposure and/or effect have not been studied. Considering that oxidative stress has been...

Detoxification of mercury (Hg) with selenium (Se) in the early postnatal period with regard to the expression of metallothionein protein (MT), essential element status, and lipid peroxidation level in tissues has not been studied. Seven-day-old Wistar pups were orally pretreated with Se [6 μmol Na2SeO3/kg body weight (b.w.)] for 3 days and then cot...

Muscle (n = 111), liver (n = 111), and kidney cortex (n = 101) samples from brown bears (Ursus arctos) were collected in the 2009 and 2010 hunting seasons in Croatia and analysed for selenium (Se), cadmium (Cd), and total mercury (Hg). The aim was to assess the levels of these elements according to age, sex, and season of collection, and to investi...

Environmental pollutants, both organic and inorganic, can have adverse effects on living organisms, as they persist in air, water, and soil and can accumulate in an individual and the food chain. The longevity, abundant food intake, and trophic position of brown bears (Ursus arctos) make this species a good bioindicator for pollution. Information g...

Strawberry tree honey is known for being rich in total phenols and its high antioxidant and antiradical activity. Apart from phenols, various major and trace elements can affect its antioxidant activity. The aim of this pilot study was to assess the beneficial effects of short-term supplementation of a usual dose of strawberry tree honey (from Pelj...

Free-living game can be an important source of dietary cadmium and lead; the question is whether exposure to these two elements is such that it might cause adverse health effects in the consumers. The aim of this study was to estimate dietary exposure to cadmium, lead, and mercury from free-living big game (fallow deer, roe deer, red deer, wild boa...

Reactive oxygen species play a role in a number of degenerative conditions including osteoporosis. Flavonoids as phyto-oestrogens exert physiological effects against oxidative stress diseases. We developed a retinoic acid-induced bone loss model of rats to assess whether flavonoids and alendronate as positive control have role against oxidative str...

Abstract A microwave-assisted digestion method for the determination of cadmium (Cd) and lead (Pb) by inductively coupled plasma mass spectrometry (ICP-MS) was optimised on certified reference material (CRM) (bovine liver, BCR-185R) and wolf liver samples. Different factors influencing digestion efficiency (temperature, time, composition of the dig...

Selenium (Se) is an essential trace element whose level in tissues depends on dietary intake and soil content. On the contrary, mercury (Hg) and cadmium (Cd) are considered ubiquitous environmental toxins known to accumulate in animal tissues. Selenoproteins and metabolites of Se are proposed to form a complex with Hg and Cd in the organism thereby...

Levels of cadmium (Cd) in the environment should be continuously monitored because of its ubiquity and ability to accumulate and exhibit toxic effects in the organism. Brown bears are suitable for Cd monitoring because of their feeding habits (omnivores) and relative longevity compared to other wild animals. There are no published data on metals in...

Due to the facts that thiomersal-containing vaccine is still in use in many developing countries, and all forms of mercury have recognised neurotoxic, nephrotoxic, and other toxic effects, studies on disposition of ethylmercury and other mercury forms are still justified, especially at young age. Our investigation aimed at comparing mercury distrib...

The aim of the study was to assess the effect of organic selenium dietary supplementation on serum and tissue lipid composition after fattening period and after 48 h fasting in fattening chicken. The study was performed in the Ross hybrid line chicken divided into two groups: control group fed standard diet and Sel Plex group fed standard diet supp...

Cadmium, lead, and mercury concentrations were determined in roe deer and wild boar tissues (muscle, liver, kidney) of three different age groups from lowland Croatia. Cadmium concentrations in the examined tissues increased with age in both species, being the highest in the kidney, and higher in roe deer as compared to wild boar. Lead concentratio...

Since there are no data about the protective role of selenium (Se) against cadmium (Cd)-induced oxidative damage in early life, we studied the effect of Se supplementation on antioxidative enzyme activity and lipid peroxidation (through thiobarbituric acid reactive substances; TBARS) in suckling Wistar rats exposed to Cd. Treated animals received e...

Continuous monitoring of mercury (Hg) levels as toxic metal in wild animals is important because of its ability to accumulate in biological tissues thereby impairing animal’s health. Also, such monitoring gives us valuable information about Hg levels in the surrounding environment. Without notable anthropogenic Hg source in studied regions of Croat...

Međudjelovanje kadmija i selenija u sisavaca Izloženost kadmiju neizbježna je zbog njegove sveprisutnosti u okolišu kao prirodne sastavnice Zemljine kore i kao onečišćenja. Kadmij može izazvati toksične učinke u gotovo cijelom organizmu vezanjem za biološke strukture i nakupljanjem u tkivima, poticanjem stvaranja slobodnih radikala, kao i međudjelo...

Selenium (Se) reduces cadmium (Cd) toxicity in adult animals, but its effects in newborn animals are still unknown. This study investigated Cd (as CdCl2) absorption, distribution, and retention in suckling rats receiving oral Se supplementation (as Na2SeO3) in equimolar doses (8 μmol Cd and/or Se per kg b.w./day). Selenium was given either before a...

It is well known that metal-metal interactions in the body are age-dependent. We studied the influence of increasing selenium (Se) doses on mercury (Hg) distribution and retention in the postnatal period in Hg-exposed suckling rats. Seven-day-old Wistar pups were pretreated with three different oral doses of Se as sodium selenite (6.45, 12.9 and 19...

In recent years cadmium has been recognized of having potency to act as metalloestrogen in mammals. We investigated earlier effects of parenteral exposure to cadmium (total dose 5 mg Cd/kg s.c.) in pregnant rats and found that it caused perturbations in element concentrations in maternal and foetal compartments, serum oestradiol concentration, and...

Kidney (n = 297), liver (n = 52), jawbone (n = 80) and muscle (n = 48) samples collected from red deer (Cervus elaphus) from north-eastern Croatia in the 2002--05 hunting season were analysed for cadmium (Cd), copper (Cu), iron (Fe), mercury (Hg), lead (Pb), selenium (Se) and zinc (Zn) using atomic absorption spectrometry. Statistical evaluation of...

Thiomersal is used as a preservative in vaccines given to small children. The metabolic product of thiomersal is ethylmercury and its distribution and kinetics are still not known, especially at this early age. The purpose of this study was to compare the body distribution of two forms of mercury: organic (thiomersal) and inorganic (mercury(2+) chl...

Neonates are a group of special concern regarding higher absorption and retention of cadmium (Cd) compared to adults. Selenium (Se) prevents the toxicity of Cd through still undefined mechanisms. Cadmium has indirect role in free radical generation. Studies have shown that free radical scavengers and antioxidants are useful in protecting against Cd...

Thiomersal (ethylmercury) used as preservative in vaccines represents a new aspect in the field of mercury toxicity. Given to infants during the vaccination period it might cause neurotoxic effect. Since data on the toxicokinetics of ethylmercury in the very young are scarce, we investigated the difference in distribution between two forms of mercu...

The aim of this study was to measure the levels of some toxic and essential metals in the kidney cortex and jawbone of red deer caught in Baranja region, Eastern Croatia. Kidneys and jawbones of 57 red deer (17 males, 40 females), aged six months to ten years, were collected and the concentrations of metals determined using atomic absorption spectr...

Cadmium (Cd) as a toxic metal is of special concern regarding exposure and effects in neonates. Selenium (Se) prevents the toxicity of Cd through undefined mechanisms causing Cd redistribution in tissues. This protective effect has not yet been studied in the early postnatal period. Suckling Wistar rats were orally exposed to CdCl2xH2O and/or Na2Se...