Bo Glas

Peroxidase-catalyzed oxidation of chlorophenols to polychlorinated dibenzo-p-dioxins and dibenzofurans

Chlorophenols are transformedin vitro to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) by peroxidase-catalyzed oxidations. This is demonstrated with bovine lactoperoxidase as well as horseradish peroxidase, and with 3,4,5- and 2,4,5-trichlorophenol (TrCP). The yield of total PCDD/Fs with lactoperoxidase was 11 μg per g 345-TrCP and 10 μg per g 245-TrCP, of which 2,3,7,8-substituted PCDD/Fs constituted 8.5 and 2.2 μg/g, respectively, corresponding to 0.85 and 1.2 μg/g of Nordic TCDD-equivalents.

Kallikrein-related peptidase 14 may be a major contributor to trypsin-like proteolytic activity in human stratum corneum.

Abstract We have previously presented evidence that two human kallikrein-related peptidases, KLK5 (hK5, stratum corneum tryptic enzyme, SCTE) and KLK7 (hK7, stratum corneum chymotryptic enzyme, SCCE), which are abundant in the stratum corneum, may be involved in desquamation. Since we had noted that not all trypsin-like activity in the plantar stratum corneum could be ascribed to KLK5, we set out to identify other skin proteases with similar primary substrate specificity. Here we describe purification of a protease identified as KLK14 from plantar stratum corneum, and show that this enzyme may be responsible for as much as 50% of the total trypsin-like activity in this tissue, measured as activity towards a chromogenic substrate cleaved by a wide variety of enzymes with trypsin-like specificity. This was in spite of very low levels of KLK14 protein compared to KLK5 and KLK7. KLK14 could be detected by immunoblotting in normal superficial stratum corneum of all individuals examined. The majority of KLK14 in the plantar stratum corneum is present in its catalytically active form. KLK14 could be immunohistochemically detected in sweat ducts, preferentially in the intraepidermal parts (the acrosyringium), and in sweat glands. The role played by this very efficient protease under normal and disease conditions in the skin remains to be elucidated.

Levels of PCDDs and PCDFs in products and effluent from the Swedish pulp and paper industry and chloralkali process

Abstract Within the Swedish Dioxin Survey various samples from the pulp and paper industry and the chloralkali process have been analyzed by congener specific analytical methods. In addition to the generally discussed “bleaching pattern” of the tetrachlorinated congeners, these samples also contained higher chlorinated congeners like hexa-CDDs, hepta-CDFs, octa-CDD and octa-CDF. Consequently it is recommended that samples from the pulp industry should be analyzed for all PCDDs and PCDFs (tetra- through octa-). Counted as Nordic Toxic Equivalents (NTEQ), the recycled pulp samples had the highest contamination level followed by TMP, unbleached sulfite and bleached softwood and hardwood. In addition to the bleaching process, various chemicals used in the pulping, bleaching and wastewater treatment can contribute to the contamination.

Variability of personal chemical exposure in eight office buildings in Sweden

This study focuses on the variability in chemical exposures for individuals working in office buildings. The study involved eight office buildings with 79 participants, and exposures were measured using personal samplers for volatile organic compounds, aldehydes, amines, nitrogen dioxide, ozone, and particles. Ventilation was assessed in each individual office. “Variability among buildings” and “variability among individuals” were evaluated for any component (of the 123) measured in samples from at least 20 persons, using variance component analysis and principal component analysis. Interpersonal differences explained the major part of the variance for 78% of the compounds versus between-buildings differences for 14% of the compounds. For 8% of compounds, the variation was explained in equal amounts by the differences among individuals and among buildings. This study illustrates the necessity for individualised measurements (versus stationary measurements in building) to estimate personal exposures. These results also support the conculsion that in case-referent studies of “sick building syndrome” (SBS), referents to SBS cases can be randomised for building location.

Formation of PCDDs and PCDFs by the chlorination of water

Abstract Two samples of tab water and double distilled water were chlorinated using chlorine gas. A series of PCDFs could be identified from these experiments, however no PCDDs could be found. The two water samples gave very similar isomeric patterns ( e . g . tetra-CDFs), however the congener profile (Cl4  Cl8) was different. These experiments indicate that all products formed by chlorination reactions are potentially contaminated by PCDFs by a specific “chlorine pattern”.

Levels of PCDDs and PCDFs in milk cartons and in commercial milk

Abstract A series of PCDDs and PCDFs have been identified in milk cartons, the levels in the old bleached products were found to be higher than in the modern bleached or unbleached products. It was found that these PCDDs and PCDFs could migrate into the milk during storage, the 1,2,7,8-tetraCDF could serve as a marker for this migration. Several factors influence the extent of this migration, among others the contamination level of the carton and the time of storage. A geographic trend has been found for unpackaged milk samples in Sweden, higher levels were found for samples in S. Sweden than from N. Sweden.