Zinc distribution within breast cancer tissue of different intrinsic subtypes.

Purpose: To show feasibility of laser ablation inductively coupled mass spectrometry (LA-ICPMS) for analysis of zinc content and concentration in breast cancer tissue and to correlate this with validated prognostic and predictive markers, i.e. histological grading and expression of steroid receptors (estrogen receptor, ER; progesterone receptor, PR) and human epidermal growth-factor receptor 2 (Her2).

Zinc distribution within breast cancer tissue: A possible marker for histological grading?

Purpose: Focusing on the trace metal zinc as a potential biomarker for breast cancer, the literature describes bulk zinc concentrations in breast cancer tissue to be higher than in normal tissue. From a histopathological point of view, cancer cells are intermingled with normal cells of the stroma within breast cancer tissues; therefore, bulk analysis cannot reflect this situation adequately. To address this problem, analysis of zinc distribution in histological sections is the method of choice.

Investigation of biomethylation of arsenic and tellurium during composting.

Though the process of composting features a high microbiological activity, its potential to methylate metals and metalloids has been little investigated so far in spite of the high impact of this process on metal(loid) toxicity and mobility. Here, we studied the biotransformation of arsenic, tellurium, antimony, tin and germanium during composting. Time resolved investigation revealed a highly dynamic process during self-heated composting with markedly differing time patterns for arsenic and tellurium species.

Parallel on-line detection of a methylbismuth species by hyphenated GC/EI-MS/ICP-MS technique as evidence for bismuth methylation by human hepatic cells.

Methylation of metal(loid)s by bacteria or even mammals is a well known process that can lead to increased toxicity for humans. Nevertheless, reliable analytical techniques and tools are indispensable in speciation analysis of trace elements, especially since environmental or biological samples are usually characterised by complex matrices. Here the methylating capability of hepatic cells was observed in vitro.

Methylated metal(loid) species in humans.

While the metal(loid)s arsenic, bismuth, and selenium (probably also tellurium) have been shown to be enzymatically methylated in the human body, this has not yet been demonstrated for antimony, cadmium, germanium, indium, lead, mercury, thallium, and tin, although the latter elements can be biomethylated in the environment. Methylated metal(loid)s exhibit increased mobility, thus leading to a more efficient metal(loid) transport within the body and, in particular, opening chances for passing membrane barriers (blood-brain barrier, placental barrier). As a consequence human health may be affected.

Effects of monomethylarsonic and monomethylarsonous acid on evoked synaptic potentials in hippocampal slices of adult and young rats.

Arsenite and its metabolites, dimethylarsinic or dimethylarsinous acid, have previously been shown to disturb synaptic transmission in hippocampal slices of rats (Krüger, K., Gruner, J., Madeja, M.

Determination of trimethylbismuth in the human body after ingestion of colloidal bismuth subcitrate.

Biological methylation and hydride formation of metals and metalloids are ubiquitous environmental processes that can lead to the formation of chemical species with significantly increased mobility and toxicity. Whereas much is known about the interaction of metal(loid)s with microorganisms in environmental settings, little information has been gathered on respective processes inside the human body as yet. Here, we studied the biotransformation and excretion of bismuth after ingestion of colloidal bismuth subcitrate (215 mg of bismuth) to 20 male human volunteers.

Methylantimony and -arsenic species in sediment pore water tested with the sediment or fauna incubation experiment.

In this study, the speciation of arsenic (As) and antimony (Sb) across a water-sediment interface and the formation of mono-, di-, and trimethylated species overtime in a microfiltered pore water solution were examined. We used an experimental technique, known as the sediment or fauna incubation experiment (SOFIE), which enables the determination of chemical speciation across redox zones in undisturbed systems. Five different incubation experiments were run: Over a 76 day incubation period, pore water was sampled and speciated 5 times.

Role of intestinal microbiota in transformation of bismuth and other metals and metalloids into volatile methyl and hydride derivatives in humans and mice.

The present study shows that feces samples of 14 human volunteers and isolated gut segments of mice (small intestine, cecum, and large intestine) are able to transform metals and metalloids into volatile derivatives ex situ during anaerobic incubation at 37 degrees C and neutral pH. Human feces and the gut of mice exhibit highly productive mechanisms for the formation of the toxic volatile derivative trimethylbismuth [(CH(3))(3)Bi] at rather low concentrations of bismuth (0.2 to 1 mumol kg(-1) [dry weight]).

Subcellular distribution of inorganic and methylated arsenic compounds in human urothelial cells and human hepatocytes.

Epidemiological studies have indicated that exposure of humans to inorganic arsenic in drinking water is associated with the occurrence of bladder cancer. The mechanisms by which arsenic induces this malignancy are still uncertain; however, arsenic metabolites are suspected to play a pivotal role. The aim of the present study was the investigation of uptake capabilities of human urothelial cells (UROtsa) compared with primary human hepatocytes (phH) as well as the intracellular distribution of the arsenic species.

Effects of dimethylarsinic and dimethylarsinous acid on evoked synaptic potentials in hippocampal slices of young and adult rats.

In this study, the effects of pentavalent dimethylarsinic acid ((CH(3))(2)AsO(OH); DMA(V)) and trivalent dimethylarsinous acid ((CH(3))(2)As(OH); DMA(III)) on synaptic transmission generated by the excitatory Schaffer collateral-CA1 synapse were tested in hippocampal slices of young (14-21 day-old) and adult (2-4 month-old) rats. Both compounds were applied in concentrations of 1 to 100 micromol/l. DMA(V) had no effect on the amplitudes of evoked fEPSPs or the induction of LTP recorded from the CA1 dendritic region either in adult or in young rats.

Speciation of alkylated metals and metalloids in the environment.

The analytical methodology for speciation of metals and metalloids associated with alkyl groups and biomacromolecules is critically reviewed. Alkylated metals and metalloids are not only known to be produced by microbial methylation within most anaerobic compartments in the environment, but also in the course of enzymatic transformations during human metabolism. Because of the toxicological relevance of these compounds present in trace to ultratrace concentrations, firm species identification and exact quantification are essential.

Blockade and enhancement of glutamate receptor responses in Xenopus oocytes by methylated arsenicals.

Pentavalent and trivalent organoarsenic compounds belong to the major metabolites of inorganic arsenicals detected in humans. Recently, the question was raised whether the organic arsenicals represent metabolites of a detoxification process or methylated species with deleterious biological effects. In this study, the effects of trivalent arsenite (AsO(3) (3-); iA(III)), the pentavalent organoarsenic compounds monomethylarsonic acid (CH(3)AsO(OH)(2); MMA(V)) and dimethylarsinic acid ((CH(3))(2)AsO(OH); DMA(V)) and the trivalent compounds monomethylarsonous acid (CH(3)As(OH)(2), MMA(III)) and dimethylarsinous acid ((CH(3))(2)As(OH); DMA(III)) were tested on glutamate receptors and on voltage-operated potassium and sodium channels heterologously expressed in Xenopus oocytes.

Methylated arsenic, antimony and tin species in soils.

Methylated species of antimony, arsenic and tin were examined in urban soils of the Ruhr basin, near the cities of Duisburg and Essen, Germany. The main aim of this study was to investigate the occurrence of mono-, di- and trimethylated species of these elements in urban soils. The influence of historical and present land use upon the species content was examined.

Determination of siloxanes, silicon, and platinum in tissues of women with silicone gel-filled implants.

Silicone [poly(dimethylsiloxane)] gel used in breast implants has been known to migrate through intact silicone elastomer shells, resulting in the clinically observable "gel bleed" on the implant surface. Although silicon concentrations in capsular tissues of women with silicone prostheses have been measured with element-specific silicon analyses, no silicone-specific investigation of these tissues has been performed as yet.A combination of element-specific inductively coupled plasma high-resolution isotope dilution mass spectrometry (ICP-HR-IDMS) and species-specific gas chromatography coupled mass spectrometry (GC-MS) was used to analyze silicon, platinum, and siloxanes in prosthesis capsule, muscle, and fat tissues of women (n=3) who had silicone gel-filled breast implants and in breast tissue of non-augmented women (n=3) as controls.