Biomedical subjects

J Szpunar

Publications and source records attributed to J Szpunar.

At least 19 recordsLinked to original sources

PubMed2003

Concentrations and bioavailability of cadmium and lead in cocoa powder and related products.

Concentrations and bioavailability of cadmium (Cd) and lead (Pb) were determined in cocoa powders and related products (beans, liquor, butter) of different geographical origins. Particular attention was paid to the fractionation of these metals, which was investigated by determining the metal fraction soluble in extractant solutions acting selectively with regard to the different classes of ligands. The targeted classes of Cd and Pb species included: water-soluble compounds, polypeptide and polysaccharide complexes, and compounds soluble in simulated gastrointestinal conditions. The bioavailability of Cd and Pb from cocoa powder, liquor and butter was evaluated using a sequential enzymolysis approach. The data obtained as a function of the geographical origin of the samples indicated strong differences not only in terms of the total Cd and Pb concentrations, but also with regard to the bioavailability of these metals. The Cd concentrations in the cocoa powders varied from 94 to 1833 microg kg(-1), of which 10-50% was potentially bioavailable. The bioavailability of Pb was generally below 10% and the concentrations measured in the cocoa powders were in the 11-769 microg kg(-1) range. Virtually all the Cd and most of Pb were found in the cocoa powder after the pressing of the liquor.

Beverages↗

PubMed2002

Development of a sequential enzymolysis approach for the evaluation of the bioaccessibility of Cd and Pb from cocoa.

An in vitro model simulating enzymatic activity in the gastrointestinal tract was developed for the assessment of the potential bioaccessibility of Cd and Pb in cocoa powder and liquor. The model was based on the sequential extraction with simulated gastric and intestinal juices; the residue after the latter extraction was further investigated by using, in parallel, solutions of phytase and cellulase. The solubility of Cd and Pb in the corresponding enzymatic extracts was measured by ICP MS. The bioaccessibility of Cd in cocoa varied from 10 to 50% in gastrointestinal conditions. An additional 20 or 30% of Cd could be recovered by phytase and cellulase, respectively. The bioaccessibility of Pb in gastrointestinal conditions did not exceed 5-10%. Only a few percent more of this metal could be recovered by extraction with phytase and cellulase.

Biological Availability↗

PubMed2002

Butyltins in sediments and three-spined stickleback (Gasterosteus aculleatus) from the marinas of the Gulf of Gdansk, Baltic Sea.

Fifty four sediment samples and three pooled samples of whole three-spined stickleback (Gasterosteus aculleatus) collected from four marinas located along the south-western coast of the Gulf of Gdańsk, Baltic Sea, Poland, were examined for butyltins (BTs) i.e., tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT), to understand the degree of pollution and distribution pattern. Total butyltin concentrations in sediments from the marina of the city of Gdynia ranged between 130 and 20,000 ng Sn/g dry wt. with a mean value of 2,900 ng Sn/g. In sediments collected from the marinas located in the area of the Brave Vistula River Channel BT concentrations ranged between 10 to 15,000 ng Sn/g drywt. with a mean values between 500 and 5,500 ng Sn/g, and the innermost sites of each of four marinas were the most polluted. The mean BT concentrations in three-spined stickleback were between 1,500 and 3,100 ng Sn/g wetwt. and the values followed mean concentrations noted in sediments from the corresponding marina. The pleasure yachts are identified as the main source of BT pollution of sediment and fish. Tributyltin was a major form of BTs present in sediments (between 24 and 43%) and in three-spined stickleback (between 54 and 70%), suggesting a very recent use of marine paints containing TBT in pleasure yachts. Evidently at the Polish coast of the Baltic Sea TBT was continuously used in 1997 in marine paints for boats less then 25 m long.

Animals↗

PubMed2001

Occurrence and effects of organotins on adult common whelk (Buccinum undatum) (Mollusca, Gastropoda) in harbours and in a simulated dredging situation.

Transplanted common whelk (Buccinum undatum) (Mollusca, Gastropoda) accumulated fairly high levels of organotins (tributyltin (TBT) and triphenyltin (TPT)) during exposure in three harbours with different TBT contamination. This did not though lead to an increase in imposex frequency in the adult females studied. Simulating harbour dredging in an experiment using suspended sediment from one of the harbours only resulted in a low concentration of TBT in the tissues of the common whelk and subsequently no changes in the occurrence and degree of imposex. The common whelk seemed to receive the main part of TBT from the water column and the limited bioaccumulation in the experiment indicates that desorption of TBT from the suspended sediment was slow. After TBT has been totally banned, dredging of contaminated sediments will cause increased exposure of the biota to TBT. Due to slow desorption the increase may however, be slight and temporary to pelagic and epibenthic species unless the settled particles are resuspended.

Animals↗

PubMed2001

Determination of phytochelatins by capillary zone electrophoresis with electrospray tandem mass spectrometry detection (CZE-ES MS/MS).

The coupling of capillary zone electrophoresis with electrospray mass spectrometry was optimized for the direct determination of phytochelatins (PCs) in extracts obtained from cells and plants that had been exposed to metal stress. Gluthathione and phytochelatins belonging to the different families (gamma Glu-Cys)nGly (n-PC), (gamma Glu-Cys)nSer, (gamma Glu-Cys)n beta Ala and (gamma Glu-Cys)n were separated in an uncoated capillary at pH 4 using a 5 mM ammonium acetate buffer, and detected by electrospray (ES) MS in the full scan mode (300-1100 u). The use of on-line tandem MS detection in the product ion scan mode of putative protonated molecules of PCs allowed the unambiguous confirmation of the identity of the compounds detected by ES MS. The operational conditions were optimized and the figures of merit were evaluated using n-PC2, n-PC3 and n-PC4 standards purified from a mixture obtained after the reaction of glutathione in the presence of Cd2+ and the enzyme PC-synthase. The method was applied to the characterization of bioinduced ligands in cell cultures of soybeans (Glycine max) and in rice (Oryza sativa) roots without the need for a preliminary sample cleanup by size-exclusion and/or reversed phase chromatography.

Chelating Agents↗

PubMed2001

Investigation of arsenic speciation in oyster test reference material by multidimensional HPLC-ICP-MS and electrospray tandem mass spectrometry (ES-MS-MS).

Multidimensional (size-exclusion-anion-exchange-cation-exchange) liquid chromatography with ICP-MS detection was developed to produce a map of water-soluble species in an oyster test reference material. The presence of arsenobetaine, trimethyl(2-carboxyethyl)arsonium inner salt, arsenocholine, dimethylarsonic acid, tetramethylammonium ion, As(v) and two arsenosugars was demonstrated by ES-MS-MS. A previously unreported compound was isolated and identified by ES-MS-MS as 5-dimethylarsinoyl-beta-ribofuranose. Anion-exchange chromatography was optimized to produce a chromatographically pure peak of arsenobetaine (accounting for ca. 64% of all water-soluble As present) that was used to quantify this compound.

Animals↗

PubMed2000