Mercury and selenium in fish from the eastern part of the Adriatic Sea: A risk-benefit assessment in vulnerable population groups.

The study examines the levels of total mercury (Hg) and selenium (Se) in the muscle tissue of 12 commercially important fish species (n = 717) from 48 locations in the eastern Adriatic Sea, as a function of fish species, size and habitat. Risks and benefits of fish consumption regarding Hg and Se in children (7 years) and women of reproductive age (30 years) were also evaluated. All samples but one were compliant with the European regulatory limit for Hg in fish muscle. Concentrations (µg g-1 ww) of Hg (range: 0.014-1.37) and Se (range: 0.184-1.12) and Se:Hg molar ratios in fish were associated with habitat type. Demersal species had the highest Hg and the lowest Se concentrations, while pelagic species had the lowest Hg concentrations, highest Se concentrations and Se:Hg molar ratios. All species had Se:Hg molar ratios above 1 (range: 1.4-66.9) and a selenium health benefit value (HBVSe) above zero (range: 3.3-9.3), indicating Se excess after Hg sequestration. The intake of two meals per week of small pelagic-neritic and bento-pelagic fish is estimated to be a valuable source of essential Se, and does not pose a risk from toxic Hg exposure in children and women during the vulnerable reproductive period. Due to the low Hg and favorable Se:Hg molar ratio and HBVSe index, small pelagic species offer a good risk to benefit ratio of fish consumption and could be considered an optimal choice in these sensitive subpopulations.

Mercury Exposure Assessment in Mother-Infant Pairs from Continental and Coastal Croatia.

The main source of mercury (Hg) exposure in the general population is fish. Another possible source is dental amalgam. Here, we compare the levels of Hg and selenium (Se) in samples of maternal and fetal origin collected shortly after childbirth of healthy postpartum women in the coastal (n = 96) and continental (n = 185) areas of Croatia related to maternal seafood/fish consumption. We also evaluated Hg concentrations and maternal serum metallothionein (MT2) concentrations in relation to the number of dental amalgam fillings, and MT2A-5A/G (rs28366003) polymorphism. The levels of Hg and Se in maternal hair and blood/serum, placenta and cord blood/serum increased in relation to increasing fish consumption with the highest values in subjects from the coast. The concentrations of each element and between elements correlated across the matrices. Increasing amalgam number correlated linearly with increased Hg levels in maternal and cord serum and was not associated with serum MT2. No association of MT2A-5A/G polymorphism and Hg or Se levels were found. The results confirmed higher fish consumption in coastal vs. continental Croatia and increases of both Hg and Se related to fish consumption in all analyzed samples. Increased blood Hg reflected the predominant MeHg share from seafood, while increased serum Hg matched exposure from dental amalgams.

Are new generations of female college-student populations meeting calcium requirements: comparison of American and Croatian female students.

We compared calcium (Ca) sources and intake, as well as multivitamin/mineral supplement use between female students with nutrition/health background and those from general-student-populations. 314 participants 18-37 y, including 57 African-Americans and 54 Caucasian-Americans recruited from Nutrition and/or other Health Sciences departments (NHS), and 100 African-American and 103 Croatian women representing general-student-population (GSP), completed food frequency questionnaire assessing their usual Ca intake and supplement use. NHS populations met recommendations and consumed significantly more Ca, particularly from dairy sources, and were more likely to take supplements than GSP groups, suggesting that health education may influence Ca intake.

Influence of selenium dose on mercury distribution and retention in suckling rats.

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 19.4 micromol Se kg(-1) b.w.) over 3 days. This was followed by simultaneous Se (as sodium selenite) and Hg (as mercury chloride) oral administration over 4 days. The molar ratio between Se and Hg given to pups was 1:1, 2:1 and 3:1, respectively. Mercury and Se were measured in brain, kidneys, liver, plasma, erythrocytes and urine of pups on the day after the last administration by atomic absorption spectrometry. Results showed that in all samples Se concentrations rose almost proportionally to the dose of Se given to pups. Mercury concentration in organs, plasma and urine decreased with higher oral doses of Se. However, Hg concentration in erythrocytes increased with increasing Se dose. There was evidently a redistribution of Hg from plasma to erythrocytes at higher ratio of Se:Hg. Approximately equimolar doses of Se and Hg are necessary to produce maximum uptake of Hg by plasma and liver and minimum retention of Hg in the kidney and erythrocytes.

[Women and medical skill--historic view]. / Zene i medicinsko umijece--povijesni ogled.

By the Banal edict of 28 June 1903, while the country was part of the Austrian-Hungarian monarchy, women physicians in Croatia were granted permission to carry out medical practice. In the memory of that occasion a historical overview of the women's role in medical science and practice is presented. The evidence of women's medical skills dates back to 2500 BC in Ancient Egypt. The 11th and 12th centuries saw first women gain access to medical schools in Europe. Women doctors practiced mainly gynaecology, obstetrics, cosmetics, skin and eye diseases. It took another seven centuries for them to be treated as men's equals as far as medical training and permission to work were concerned. In the 18th and 19th centuries the number of female physicians greatly increased in Europe, USA, and Canada. In Croatia the first woman medical doctor was Milica Sviglin Cavov, who graduated from the Medical School in Zürich in 1893, but was not allowed to work in the home country. The first woman to practice medicine in Croatia was Karola Maier Milobar in 1906. The first woman to have graduated from the Medical School in Zagreb, capital of Croatia, following its opening in 1917, was Kornelija Sertic The paper concludes with a view of the present-day role of women in medical practice, education and science.

Chelators as antidotes of metal toxicity: therapeutic and experimental aspects.

The effects of chelating drugs used clinically as antidotes to metal toxicity are reviewed. Human exposure to a number of metals such as lead, cadmium, mercury, manganese, aluminum, iron, copper, thallium, arsenic, chromium, nickel and platinum may lead to toxic effects, which are different for each metal. Similarly the pharmacokinetic data, clinical use and adverse effects of most of the chelating drugs used in human metal poisoning are also different for each chelating drug. The chelating drugs with worldwide application are dimercaprol (BAL), succimer (meso-DMSA), unithiol (DMPS), D-penicillamine (DPA), N-acetyl-D-penicillamine (NAPA), calcium disodium ethylenediaminetetraacetate (CaNa(2)EDTA), calcium trisodium or zinc trisodium diethylenetriaminepentaacetate (CaNa(3)DTPA, ZnNa(3)DTPA), deferoxamine (DFO), deferiprone (L1), triethylenetetraamine (trientine), N-acetylcysteine (NAC), and Prussian blue (PB). Several new synthetic homologues and experimental chelating agents have been designed and tested in vivo for their metal binding effects. These include three groups of synthetic chelators, namely the polyaminopolycarboxylic acids (EDTA and DTPA), the derivatives of BAL (DMPS, DMSA and mono- and dialkylesters of DMSA) and the carbodithioates. Many factors have been shown to affect the efficacy of the chelation treatment in metal poisoning. Within this context it has been shown in experiments using young and adult animals that metal toxicity and chelation effects could be influenced by age. These findings may have a bearing in the design of new therapeutic chelation protocols for metal toxicity.

Succimer treatment and calcium supplementation reduce tissue lead in suckling rats.

The effect of combined treatment with meso-2,3-dimercaptosuccinic acid (DMSA) and calcium supplementation in reducing lead absorption and enhancing lead elimination was evaluated in suckling rats under two experimental conditions: during ongoing oral lead exposure (lead acetate, 2 mg Pb kg(-1) day(-1), total dose 16 mg Pb kg(-1)) or after lead exposure (72 h after a 2-day lead exposure, total dose 12 mg Pb kg(-1) s.c.). The artificial feeding method was used for calcium supplementation, with 6% Ca (as CaHPO(4)) suspension in cow's milk to increase the daily calcium intake about three times above control values. Artificial feeding lasted for 7 h a day over eight consecutive days. During this period DMSA was administered on 6 days twice a day (0.5 mmol kg(-1) day(-1) p.o.). At the end of the experiments, Pb, Ca and Zn in the carcass and Pb, Fe and Cu in the liver, kidneys and brain were analysed by atomic absorption spectrometry. Calcium supplementation during lead exposure reduced tissue lead but had no effect when applied after lead exposure, and DMSA administered either during or after lead exposure lowered the tissue lead. Combined treatment during ongoing lead exposure caused a greater reduction in tissue lead than either DMSA or calcium treatment alone. When administered after lead exposure, it had no advantage over DMSA treatment alone but did not impair its efficacy. Combined treatment had no influence on growth and did not seriously disturb essential element status. It is concluded that calcium supplementation could be applied during DMSA therapy, when indicated.

The effect of dietary supplementation with calcium salts on skeletal calcium in suckling rats.

This study aimed at identifying a calcium compound which could serve as an effective and safe dietary supplement in suckling rats over the period of intense growth and development. The main objective was to assess the effect of additional calcium intake on skeletal calcium in suckling pups. Suckling Wistar rats were fed using a pipettor with one of the following calcium salts from day 6 to 14 after the birth: gluconate, hydrogenphosphate, carbonate (each suspended in cow's milk), or chloride (in demineralized water). Control rats received only cow's milk. Calcium in the carcass (body without organs and skin) was analysed by atomic absorption spectrometry. The only effective dietary supplement that produced no risk for the suckling pups' growth was calcium hydrogenphosphate in cow's milk in the total amount of 340 mg. That dose increased the daily calcium intake 3 to 4 times compared to non-supplemented controls, increasing carcass calcium content by about 16 per cent. Other calcium compounds were either inefficient (carbonate) or had adverse effects on pups' growth (chloride and gluconate).

Ascorbic acid supplementation does not improve efficacy of meso-dimercaptosuccinic acid treatment in lead-exposed suckling rats.

It was suggested that ascorbic acid as a natural chelating agent can influence lead toxicokinetics and improve chelating properties of dimercaptosuccinic acid (DMSA) in adult rats. In this paper potential benefits of ascorbic acid supplementation, alone or combined with DMSA, in decreasing lead retention in suckling rats were evaluated. Such data in young mammals are not available. L-Ascorbic acid (daily dose 650 mg/kg b.wt.) and/or DMSA (daily dose 91 mg/kg b.wt.) were administered orally to suckling Wistar rats either during ongoing 8-day oral lead exposure (as acetate; daily dose 2 mg lead/kg b.wt.) or after 3-day lead exposure (total dose 12 mg lead/kg b.wt.). Lead concentrations were analysed in the carcass (skeleton), liver, kidneys and brain by atomic absorption spectrometry. By ascorbic acid supplementation lead retention was not reduced under either lead exposure condition. Lead concentration was even increased in the carcass. Treatment with DMSA under both exposure conditions significantly reduced lead in all analysed tissues. Combined treatment with ascorbic acid and DMSA during ongoing lead exposure was substantially less effective than DMSA treatment alone, and did not affect DMSA efficacy when administered after lead exposure. It was concluded that ascorbic acid administered either during or after lead exposure in suckling rats has no beneficial effect on either lead retention or DMSA chelation effectiveness.

Effect of dietary calcium on cadmium absorption and retention in suckling rats.

The effect of calcium supplementation on absorption and retention of cadmium in the suckling period was evaluated in Wistar rat pups of both sexes. Animals were maintained in the litters with the mother rats and supplemented with 1%, 3% or 6% calcium (as CaHPO4 x 2H2O) in cow's milk by artificial feeding from day of birth 6 through 14. All rats were exposed to cadmium (as CdCl2 x H2O) either orally or parenterally. Oral cadmium dose of 0.5 mg/kg body weight a day was administered through nine-day period of calcium supplementation and parenteral cadmium dose was injected subcutaneously in a single dose of 0.5 mg Cd/kg body weight prior to calcium supplementation. On experimental day 10 (at the age of pups of 15 days) all animals were killed and the liver, kidneys, brain and carcass (body without organs and skin) were removed for element analyses. Cadmium and essential elements calcium, zinc and iron were analysed in the tissues by atomic absorption spectrometry. Results showed that after oral exposure cadmium concentrations in all calcium-supplemented groups were significantly decreased in the organs and carcass and that the effect was dose-related. No such effect of calcium was found after parenteral cadmium exposure. Calcium supplementation per se significantly increased calcium concentration in the carcass and had no effect on iron in organs and zinc in carcass. It was concluded that calcium supplementation during the suckling period could be an efficient way of reducing oral cadmium absorption and retention without affecting tissue essential trace element concentrations.