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PubMed1999

Trace element transfer from the mother to the newborn--investigations on triplets of colostrum, maternal and umbilical cord sera.

OBJECTIVE: To investigate the trace element transfer from the mother to the newborn. DESIGN: The concentrations of the eight essential elements calcium (Ca), cobalt (Co), copper (Cu), magnesium (Mg), manganese (Mn), molybdenum (Mo), tin (Sn), and zinc (Zn), and of the non-essential and toxic elements barium (Ba), beryllium (Be), bismuth (Bi), cadmium (Cd), cesium (Cs), lanthanum (La), lithium (Li), lead (Pb), rubidium (Rb), antimony (Sb), strontium (Sr), and thallium (Tl) were determined in umbilical cord (n = 29) and corresponding maternal sera (n = 29) as well as in colostrum (n = 27). RESULTS: Umbilical cord serum concentrations of Ca, Mn, and Zn were 120%, 150%, and 148% of the maternal value, respectively. Maternal sera had twice the Cu concentrations found in healthy adults and five-times higher Cu than umbilical cord sera. Concentration ratios colostrum/maternal serum and colostrum/umbilical cord serum were approximately one for Co, 1.4 for Mg, two for Ca, Mn, and Sn, five for Cu (maternal serum), eight for Mo, and ten for Zn. Concentrations of the toxic elements Cd and Pb decreased in the order colostrum (Pb 2.6 microg/L; Cd 0.6 microg/L), maternal sera (0.8 microg/L; 0.3 microg/L), umbilical cord sera (0.4 microg/L; 0.2 microg/L). Maternal serum Ba and Rb was 182% and 66% of the umbilical cord value. For Sr and Li, an almost perfect correlation between umbilical cord and maternal sera was found. For Ba, Co, Cu, Mn, Zn none, and for Ca, Cs, Mn, Mo, Rb only weak positive correlations between these two compartments could be established. CONCLUSIONS: The results of this study indicate that an active transport mechanism for the transport of Ca, Mn, Rb, and Zn from the mother to the newborn exists, whereas Cs, Li, and Sr follow concentration gradients. As regards Cu, the placenta showed to have a blocking effect on the transfer from the mother to the baby.

Adult↗

PubMed2001

Factor analysis of essential and toxic elements in human placentas from deliveries in arctic and subarctic areas of Russia and Norway.

Concentrations in human placenta of 11 essential elements (P, Ca, Mg, Cu, S, Na, Fe, Zn, K, Se, Mn) and 5 toxic elements (Ba, Sr, Pb, Ni, Cd) are compared for each of two arctic communities in eastern Norway and western Russia, and for another in each country located at more southerly latitudes. All but Mg, Fe, P and K were present in higher concentrations in the Russian study group. The observed inter-element correlations are reflected by the four major factors identified in a principal component analysis. The total variation explained was 67.3%, of which more than half (35.3%) was contributed by Factor 1. P, Ca, Mg, Ba, Sr, Pb, and Ni were major contributors to this factor. The placental concentrations of these elements depended strongly on gestational age, increasing from about week 35 and peaking near weeks 39 and 40, and exhibited skewed frequency distributions and a dependence on maternal smoking. The gestational-dependent mineralization of the placenta is interpreted to reflect the deposition of metal phosphates coinciding with smoking-induced tissue damage. The loadings of the remaining three factors are reviewed in the context of common uptake mechanisms, similar biochemistries and unique transport pathways. The inter-element relationships and grouping of the elements observed should constitute a scientific base for the use of placenta composition in environmental monitoring and epidemiological studies.

Adult↗

PubMed2002

Profile of trace element concentrations in the feto-placental unit in relation to fetal growth.

BACKGROUND: During pregnancy, trace elements are indispensable for life maintenance not only for the mother but also for the fetus. The purpose of this study was to examine whether fetal growth is associated with altered levels of trace elements in maternal blood, fetal blood, and placenta tissue. METHODS: Twenty-one pairs of healthy mothers and their newborns with intrauterine growth restriction delivered after 34 weeks of gestation were recruited for the study. In addition, 30 pairs of healthy mothers and their appropriate for gestational age newborns were included as controls. Maternal venous blood, umbilical cord venous and arterial blood, and placenta tissue were collected immediately after delivery. Six essential elements, magnesium, manganese, iron, copper, zinc, and selenium, and four other elements, rubidium, strontium, cadmium, and cesium, in those samples were determined by inductively coupled plasma mass spectrometry or inductively coupled plasma atomic emission spectrometry. RESULTS: Compared with appropriate for gestational age cases, intrauterine growth restriction cases showed higher magnesium, copper, and selenium concentrations in umbilical cord arterial sera, and higher magnesium and selenium concentrations in placenta tissue, but no significant differences appeared for the elements measured in maternal and umbilical cord venous sera. The umbilical cord venous vs. maternal sera concentration ratio was elevated for copper, and the umbilical cord arterial vs. umbilical cord venous sera concentration ratios were elevated for copper and zinc, but there were no differences in placenta tissue vs. maternal sera concentration ratios in intrauterine growth restriction cases. CONCLUSIONS: Among the trace elements evaluated, magnesium, copper, zinc, and selenium showed elevated concentrations in umbilical cord arterial blood, or elevated umbilical cord arterial vs. umbilical cord venous blood concentration ratios in intrauterine growth restriction cases. Reduced consumption efficiency of these four essential trace elements may be closely associated with retarded fetal development.

Adult↗

PubMed1992

Criteria for the definition of reference values for toxic metals.

Two types of selection are used to identify subjects who make up reference groups: 'a posteriori' selection starting from a large number of subjects who are then subsequently selected and 'a priori' selection wherein the group to be examined is defined on the basis of preestablished criteria. The main variability factors are biological and those depending on the modalities of selection of groups and determination of the analysis. The nature of the element is also particularly important, i.e. whether an essential element must be considered only a micropollutant or whether it should be considered essential and at the same time a micropollutant. In addition two other factors which play an important role are the temporo-spatial modifications induced by natural or anthropogenic phenomena which influence the modality and degree of exposure in man. Two criteria are generally used in the production of reference groups: exclusion/inclusion and partitioning criteria. While in clinical chemistry the health status represents an important exclusion factor, in the case of metals, the environmental conditions and the function of organs and apparatuses involved in the toxicokinetics of metals can be considered as main criteria. All the other variables such as sex, age, life-style are partitioning criteria and enable us to obtain reference values for more and more homogeneous subgroups.

Adult↗

PubMed1994

Analysis of an insulin gene transcription control element. Positive and negative regulation appears to be mediated by different element sequences.

Pancreatic beta-cell-type-specific transcription of the insulin gene is controlled by cis-acting sequence elements lying within its enhancer region. An essential element required for expression is the insulin control element (ICE). The activity of this element is regulated by both positive- and negative-acting transcription factors. In this study, we have identified the nucleotide sequences within the ICE that are required for repression in noninsulin producing cells. Our results indicate that the cis-acting sequences involved in negative control are distinct from those required in activating expression in beta cells.

Animals↗

PubMedDate not supplied

Selenium interactions with carcinogens.

Although selenium was once considered to be a toxic, undesirable and carcinogenic element, it is now recognized as an essential element with anticarcinogenic properties. Epidemiological studies in the United States have shown an inverse relationship between selenium intake and certain forms of cancer in humans, but other factors must be considered since cancer is not higher in people living in selenium-deficient areas of the world (Finland, New Zealand, and Keshan disease area, China). Under most dietary conditions, selenium has been shown to reduce the spontaneous mammary tumor incidence in an inbred strain of mice. In general, selenium will counteract to various degrees, the chemical carcinogens used to produce lesions of the skin [coal tar, 3-methylcholanthrene, alpha-pyrene, and 7,12 dimethylbenz(a) anthracene (DMBA)], liver (3-methyl-4-dimethyl-aminoazobenzene, aflatoxin B1, and 2-acetylaminofluorene), mammary gland (DMBA and N-methyl-N-nitrosurea), and intestinal tract [1,2-dimethylhydrazine, bis(2-oxopropyl)nitrosamine, and azoxymethane]. Dietary factors, such as fat, will modify the protective effects of selenium. High dietary unsaturated fats, for example, markedly increase the mammary tumors in rats treated with DMBA, and selenium will reduce the tumor incidence but not to the level of rats fed a low fat diet. Other factors known to affect the anticarcinogenic effects of selenium include synthetic antioxidants, vitamin E, vitamin A and ascorbic acid. The mechanisms of selenium counteraction of carcinogens remain unknown.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1999

The potential of inductively coupled plasma mass spectrometry (ICP-MS) for the simultaneous determination of trace elements in whole blood, plasma and serum.

The advantages accruing to biochemical and clinical investigations from a method that allows the simultaneous quantification (RSD < or = 10%) of many elements in blood, plasma, and serum at concentrations equal to one-hundredth of the lower limits of the normal ranges are undeniable. The suitability of inductively coupled argon plasma low-resolution quadrupole mass spectrometry (ICP-MS), a simultaneous method with low detection limits, is evaluated for the quantification of inorganic constituents in whole blood, plasma, and serum with consideration of the dilution associated with the mineralization of the samples, of isobaric and polyatomic interferences and of normal ranges. Of the 3 bulk elements, the 3 major electrolytes, the 15 essential elements, the 8 toxic elements, the 4 therapeutic elements, and the 14 elements of potential interest (total of 47 elements) only 7 elements (Ca, Cu, K, Mg, Rb, Sr, Zn) can be simultaneously quantified under these rigorous conditions in serum and only 8 elements (additional element Pb) in whole blood. Quantification of elements in the Seronorm Standards "Whole Blood" and "Serum" showed, that this list of simultaneously determinable elements in these matrices is reasonable. Although this list is disappointingly short, the number of elements determinable simultaneously by ICP-MS is still larger than that by ICP-AES or GFAAS. Improved detectors, more efficient nebulizers, avoidance of interferences, better instrument design, and high-resolution mass spectrometers promise to increase the number of elements that can be determined simultaneously.

Humans↗

PubMed1990

Regulation of the Discoidin I gamma gene in Dictyostelium discoideum: identification of individual promoter elements mediating induction of transcription and repression by cyclic AMP.

We dissected the promoter of the developmentally induced and cyclic AMP-repressed discoidin I gamma gene and identified a sequence element essential for developmental induction. Transfer of the element to an inactive heterologous promoter demonstrated that this sequence is sufficient to confer expression in axenically growing cells and to induce gene activity in development after growth on bacteria. A 16-base-pair sequence within this element was shown to be sufficient for induction in the discoidin promoter context and was used to reactivate different truncated promoter constructs. This led to the localization of an element necessary for down regulation of gene expression by extracellular cyclic AMP.

Base Sequence↗

PubMedDate not supplied

Regulation of dopamine-1A (D1A) receptor gene transcription.

The D1A receptor is expressed primarily in the brain and kidney. The D1A receptor gene has been cloned from human, rat and pig and is organized similarly in each species. The 5' flanking region of the D1A receptor gene is high in GC content, is TATA box-less and contains multiple Sp1 binding sites. Comparison and alignment of the nucleotide sequences within the 5' flanking and 5' untranslated regions of each gene indicates that the highest sequence identity is in the area centered approximately 100 bases upstream from the transcription start site. There are numerous binding sites for transcription factors, including Sp1 and AP-2, in the 5' flanking region. Approximately 200 bases upstream is a conserved cAMP regulatory element-like sequence. The conserved position of certain cis-acting elements in each gene suggests that the essential elements for regulated expression of the D1A receptor gene are contained within the first 300 bases of the 5' flanking region.

Animals↗

PubMed1991

Analysis of an origin of DNA replication located at the L terminus of the genome of pseudorabies virus.

We have localized an origin of DNA replication at the L terminus of the pseudorabies virus genome. This origin differs in location as well as in general structure from the origins of replication of other herpesviruses that have been identified. The 600 leftmost nucleotides of the genome that were found to include origin function have been analyzed. This sequence is composed of an 82-bp palindrome whose center of symmetry is separated by 352 unique bp (UL2). Within the UL2, a sequence that fits the consensus sequence of the NF1 binding site, as well as one that has partial homology to the binding site of UL9 of herpes simplex virus, is present. Using truncated fragments of DNA, sequences essential for minimal origin function were delimited to within a fragment that includes the terminal 104 bp of the left end of the genome. Within these 104 bp, two elements essential to origin function have been identified. One of these elements is present within the terminal 64 bp of the L component (within one of the palindromic arms). The other is present within the 22 bp of the UL2 adjacent to this palindromic arm. Other auxiliary elements, although not essential for origin function, contribute to more efficient replication. The NF1 and UL9 binding site homologies were found to be nonessential to origin function.

Animals↗

PubMed1996

Behavioral, neural and cellular components underlying olfactory learning in the honeybee.

A top-down approach as applied to learning and memory in honeybees provides the opportunity of relating different levels of complexity to each other, and of analyzing the rules and mechanisms from the viewpoint of the respective next higher level. Olfactory conditioning of harnessed bees exemplifies essential elements of associative learning and, in general, forms a bridge between the systems and the cellular levels of analysis. Intracellular recordings of identified neurons during olfactory conditioning play a key role in this effort. They allow testing of the assumptions made by modern behavioral theories of associative learning and provide access to cellular and molecular studies, owing to the identification of their transmitters and the peculiarities of the connectivities. Analysis at this intermediate level of complexity is particularly profitable in the bee, because essential neural elements of the associative network are known and can be tested during ongoing learning behavior. In this respect, the honeybee offers unique properties for the building of bridges between the molecular, cellular, neuronal, network and behavioral levels of associative learning.

Animals↗

PubMed2003

Effect of iodine and selenium upon thyroid function.

Iodine is an essential element with unique role in organism: it is indispensable component of thyroid hormones. After binding with specific nuclear receptor, T3/T4 induce transcription of genetic code via mRNA and regulate proteosynthesis in most tissues. Thyroid hormones regulate rate of metabolic processes and consequently development of organism. Czech Republic was in past typical region with moderate to severe iodine deficiency. Therefore epidemiological survey was started in randomly selected samples of peoples. Thereafter a complex program of improving iodine supply was realized. Prompt effects of this changes were recorded, namely increase of ioduria and decrease of thyroid volume. Essential trace element selenium has a fundamental importance to the cell and body metabolism regulation by thyroid hormones. Activities of selenoenzymes deiodinases lead to the activation of prohormone T4 to active hormone T3 and the inactivation of T3 and of T4, as well. There is unfortunately moderate to mild Se deficit in the CR. Average serum Se concentrations for the populations from 6 to 65 years are in the regions of the CR between 42 and 62 micrograms/l and urine Se values are between 8 and 15 micrograms/l. We have found statistically significant correlations among indexes of selenium status and indexes of thyroid hormone metabolism and function. Especially dangerous are concomitant deficiencies of both key elements for thyroid hormone metabolism--I and Se--from the point of thyroid hormone regulative functions.

Adolescent↗

PubMed1983

Minireview: physiological and pharmacological properties of vanadium.

Vanadium is distributed extensively in nature. It is a trace element and is present in almost all living organisms including man. Even though vanadium was originally recognized for its ability to inhibit membrane Na+-K+-ATPase, various laboratory studies now document that this element has the capacity to affect the activity of various intracellular enzyme systems and may modify their physiological functions. Vanadium may be an essential element for normal development and may play an important role in various homeostatic mechanisms, and thus vanadium deficiency may prove to be an important concern. Abnormalities in biological disposition of vanadium may be involved in the pathogenesis of certain neurological disorders or cardiovascular diseases. While the essentiality of this element for living organisms is yet to be established with certainty, vanadium has become an increasingly important element and is used extensively in various heavy industries such as steel, oil, etc.; thus, the incidence of exposure to toxic levels of vanadium to industrial workers has been an increasing concern for toxicologists. To date, little information is available on the physiological or pharmacological actions of vanadium; hence, it is difficult to reach any definitive conclusion concerning its biological significance, essentiality and its role in pathological states. An attempt has been made in this review to broadly document what is known of various biological actions of vanadium.

Animals↗

PubMed2005

Regulation of the Rhox5 homeobox gene in primary granulosa cells: preovulatory expression and dependence on SP1/SP3 and GABP.

Homeobox genes encode transcription factors that regulate embryonic development and postnatal events. Rhox5 (previously called Pem), the founding member of a homeobox gene cluster that we recently identified on the X chromosome, is selectively expressed in granulosa cells in the ovary and other somatic-cell types in other reproductive organs. In this report, we investigate its regulation in granulosa cells in the rat ovary. We found that Rhox5 expression in the ovary is governed by the Rhox5 distal promoter and is expressed at least as early as Day 5 postpartum. Rhox5 mRNA levels are regulated during the ovarian cycle, peaking before ovulation. Deletion analysis revealed a 25-nt element essential for distal promoter transcription in primary granulosa cells. This distal promoter element contains two ETS and one SP1 transcription-factor family binding sites that mutagenesis analysis indicated were essential for high-level transcription. This element was both necessary and sufficient for transcription, because it activated transcription when placed upstream of a heterologous minimal promoter. Cold competition and electrophoretic mobility shift assay studies demonstrated that SP1, SP3, and the ETS family transcription factor GABP bound this element. Dominant-negative forms of GABP and SP3 repressed distal promoter expression in primary rat granulosa, showing that these factors are crucial for Rhox5 expression. Cotransfection of dominant-negative mutants indicated that Rhox5 expression in granulosa cells is regulated by the c-Jun N-terminal protein kinase (JNK, MAPK8) and RAS pathways, which are known to be upstream of ETS family transcription factors. The discovery that Rhox5 expression in granulosa cells is regulated by MAPK pathways and ETS and SP1 family members provides an opportunity to understand how these regulatory pathways and factors collaborate to regulate gene expression during the ovarian cycle.

Animals↗

PubMed2005

Effect of heavy metals on, and handling by, the kidney.

Heavy metals such as cadmium (Cd), mercury (Hg), lead (Pb), chromium (Cr) and platinum (Pt) are a major environmental and occupational hazard. Unfortunately, these non-essential elements are toxic at very low doses and non-biodegradable with a very long biological half-life. Thus, exposure to heavy metals is potentially harmful. Because of its ability to reabsorb and accumulate divalent metals, the kidney is the first target organ of heavy metal toxicity. The extent of renal damage by heavy metals depends on the nature, the dose, route and duration of exposure. Both acute and chronic intoxication have been demonstrated to cause nephropathies, with various levels of severity ranging from tubular dysfunctions like acquired Fanconi syndrome to severe renal failure leading occasionally to death. Very varied pathways are involved in uptake of heavy metals by the epithelium, depending on the form (free or bound) of the metal and the segment of the nephron where reabsorption occurs (proximal tubule, loop of Henle, distal tubule and terminal segments). In this review, we address the putative uptake pathways involved along the nephron, the mechanisms of intracellular sequestration and detoxification and the nephropathies caused by heavy metals. We also tackle the question of the possible therapeutic means of decreasing the toxic effect of heavy metals by increasing their urinary excretion without affecting the renal uptake of essential trace elements. We have chosen to focus mainly on Cd, Hg and Pb and on in vivo studies.

Animals↗

PubMed2000

The Biological System of the Elements (BSE). Part II: a theoretical model for establishing the essentiality of chemical elements. The application of stoichiometric network analysis to the biological system of the elements

Stoichiometric Network Analysis (SNA), originally developed by the Canadian chemist Bruce L. Clarke during the 1970s, provides a most efficient means of reducing the background topology of complex interaction networks to some skeleton topology around which systems dynamics can be understood without jeopardising insight into complex dynamics by over- or miss-simplification. Since it focuses on the corresponding autocatalytic (AC) features of a feedback system as those which control overall behaviour to some extent, SNA deals with reaction kinetics in and beyond chemistry, e.g. with nuclear reactions. It is therefore quite straightforward to apply this manner of simplification, which in turn is supported by a number of mathematical theorems on systems behaviour and properties of AC cycles, to biological systems although their 'full' complexity may not even be assessed in the yet rare cases of complete genetic sequencing. Assuming there is a relationship between the kinds of metal or metalloid species and key biological/biochemical transformations to be promoted with their aid--this relationship being the subject of bio-inorganic chemistry--and that biochemistry is, in effect, about systems which can reproduce and thus behave autocatalytically, one can expect SNA to yield formally sound statements on basic features of biology and biochemistry too. If we sum up the facts and considerations concerning essentiality or possible essentiality in a biological system of elements (Markert, 1994), this means joining the triangular representation of BSE, including statements on (the degree of biological) evolution and aggregation levels, to SNA treatment of autocatalysis within hierarchical systems from metalloenzymes to entire biocoenoses. Arguments using preferred cluster sizes and aggregation tendencies from coordination chemistry are then employed to circumscribe possible functions within the BSE. They are also extended to metals hitherto not known to be essential, such as tellurium or scandium.

Journal Article↗

PubMed2006

Essential and toxic elements in seafood available in poland from different geographical regions.

The concentrations of 15 elements (Cu, Fe, Mn, Zn, Co, Ni, Cr, Se, Cd, Pb, Hg, Ca, Na, K, and Mg) were determined in the edible parts of shellfish on sale in the local market in Gdańsk. The samples consisted of three groups--crustaceans, molluscs, and surimi--that are processed to different degrees. For the purposes of this analysis, they were dried, homogenized, and digested in an automatic microwave system. The samples were analyzed quantitatively for Cu, Zn, Fe, Mn, Co, Ni, Cr, Mg, Na, K, and Ca (F-AAS), Cd and Pb (GF-AAS), Se (HG-AAS), and Hg (CV-AAS). The elemental levels detected in shellfish were compared to those in cod, herring, pork, beef, chicken, and eggs. The recommended dietary allowance (RDA) of essential elements and the provisional tolerable weekly intake (PTWI) of toxic elements were estimated. With factor analysis of the data, taxonomically different groups of raw and processed shellfish could be distinguished.

Animals↗

PubMed1994

[Liver cirrhosis in primary hemochromatosis and Wilson's disease].

Iron is an essential element in all living cells because it serves machineries for biological oxidation including hemoglobin, cytochrome c oxidase, etc. Copper is also essential for mammalian life since copper is the prosthetic element of several life-essential enzymes. Although intracellular excessive iron and copper were usually sequestrated in ferritin and metallothionein molecules, accumulation of excess iron and copper may also cause severe tissue injury by including oxyradicals and lipid peroxidation and eventually bring about tissue fibrosis such as liver cirrhosis. Hemochromatosis and Wilson's disease are known as iron and copper accumulation disorders, respectively. In this chapter, we review the cirrhosis in hemochromatosis and Wilson's disease.

Hemochromatosis↗