Phenolic xenoestrogens in surface water, sediments, and sewage sludge from Baden-Württemberg, south-west Germany

Nine structurally different phenolic chemicals, which have been reported to mimic estrogen effects, were determined in various aquatic environmental compartments. Twenty-three water samples from five streams and rivers showed levels up to 458 ng/l for 4-nonylphenol (4NP), 189 ng/l for 4-t-octylphenol (4tOP), 272 ng/l for bisphenol A (BPA) and 47 ng/l for 2-hydroxybiphenyl (2OHBiP). Elevated levels of these compounds in a stream with a high load of effluents of sewage treatment plants (STPs), compared to a brook free of sewage, identified STPs as major sources. With a similar order, 4NP (10-259 micrograms/kg dry matter), 4tOP (< 0.5-8 micrograms/kg), BPA (< 0.5-15 micrograms/kg), and 2OHBiP (2-69 micrograms/kg) were also detected regularly in riverine sediment (n = 11). Levels in sewage sludge were one order of magnitude higher than in sediments. 4-Hydroxybiphenyl and 4-chloro-3-methylphenol were found predominantly in sludge and sediment in the lower ppb range.

Intracellular protein binding patterns of the anticancer ruthenium drugs KP1019 and KP1339

The ruthenium compound KP1019 has demonstrated promising anticancer activity in a pilot clinical trial. This study aims to evaluate the intracellular uptake/binding patterns of KP1019 and its sodium salt KP1339, which is currently in a phase I-IIa study. Although KP1339 tended to be moderately less cytotoxic than KP1019, IC(50) values in several cancer cell models revealed significant correlation of the cytotoxicity profiles, suggesting similar targets for the two drugs. Accordingly, both drugs activated apoptosis, indicated by caspase activation via comparable pathways. Drug uptake determined by inductively coupled plasma mass spectrometry (ICP-MS) was completed after 1 h, corresponding to full cytotoxicity as early as after 3 h of drug exposure. Surprisingly, the total cellular drug uptake did not correlate with cytotoxicity. However, distinct differences in intracellular distribution patterns suggested that the major targets for the two ruthenium drugs are cytosolic rather than nuclear. Consequently, drug-protein binding in cytosolic fractions of drug-treated cells was analyzed by native size-exclusion chromatography (SEC) coupled online with ICP-MS. Ruthenium-protein binding of KP1019- and KP1339-treated cells distinctly differed from the platinum binding pattern observed after cisplatin treatment. An adapted SEC-SEC-ICP-MS system identified large protein complexes/aggregates above 700 kDa as initial major binding partners in the cytosol, followed by ruthenium redistribution to the soluble protein weight fraction below 40 kDa. Taken together, our data indicate that KP1019 and KP1339 rapidly enter tumor cells, followed by binding to larger protein complexes/organelles. The different protein binding patterns as compared with those for cisplatin suggest specific protein targets and consequently a unique mode of action for the ruthenium drugs investigated.

Anticancer activity of the lanthanum compound [tris(1,10-phenanthroline)lanthanum(III)]trithiocyanate (KP772; FFC24)

Aim of this study was to investigate the anticancer properties of the new lanthanum compound [tris(1,10-phenanthroline)lanthanum(III)]trithiocyanate (KP772; FFC24). In vitro, growth inhibition by KP772 was comparable for >60 tumour cell models with IC50 values generally in the low microM range. KP772 induced tumour cell apoptosis indicated by chromatin condensation, caspase substrate cleavage and mitochondrial membrane depolarisation. DNA is unlikely to represent the primary molecular target of KP772, as no significant interaction or damage of DNA was detectable both in vitro and in living cells. Moreover, we found no evidence for induction of radical species. In contrast, KP772 potently inhibited DNA synthesis paralleled by a massive block of cell cycle in G0/G1 phase and a selective decrease of cyclin B1. Although treatment with KP772 induced expression of p53 and p21Waf1, transfection of wild-type p53 into knock-out cells only marginally enhanced the cytostatic activity of KP772. In vivo, the anticancer activity of KP772 against human DLD-1 colon carcinoma xenografts was comparable to that of cisplatin and methotrexate at doses not causing significant adverse effects. With regard to toxicity, the LD50 and no-observed-adverse-effect levels (NOAEL) of KP772 in Sprague-Dawley rats were 21.6 and 7.5 mg/kg, in outbred albino mice 62 and 10 mg/kg, respectively. In summary, KP772 exerts anticancer activity via potent induction of cell cycle arrest and/or apoptosis and has promising in vivo anticancer activity against a human colon cancer xenograft. Together, these data suggest further development of KP772 as a new anticancer metal-drug.

Estrogenic activity of musk fragrances detected by the E-screen assay using human mcf-7 cells

The widespread use of synthetic musk fragrances and the resultant presence of these substances and their metabolites in the aquatic environment (as well as their accumulation in human adipose tissue) raises the question of whether musk fragrances display endocrine and in particular estrogenic activity. A variety of musk fragrances were tested using the E-screen assay. A statistically significant increase in proliferation rate of human MCF-7 breast cancer cells was detected for two nitro musks (musk xylene, musk ketone), a major metabolite of musk xylene ( p-amino-musk xylene), and the polycyclic musk fragrance AHTN. This indicates that these substances do, in fact, demonstrate estrogenic activity. Coincubation with the antiestrogen tamoxifen showed that the increase in proliferation rate by the musk fragrances is estrogen receptor-mediated. It must be noted, however, that the effective estrogenic strength and estrogenic potency were low compared to 17 b-estradiol. The naturally occurring fragrance muscone from the group of macrocyclic musk fragrances, a group of substances that have not yet been well characterized in respect to their toxicological properties, has also been shown to be weakly estrogenically active in vitro. E-screen analysis showed that the nitro musk metabolites o-amino musk xylene and 2-amino-MK, the macrocyclic musk fragrances ethylene brassylate, ethylene dodecandioate, and cyclopentadecanolide, are not estrogenically active.

Input/output balance of estrogenic active compounds in a major municipal sewage plant in Germany

24 h samples of untreated and treated wastewater were taken in parallel from a modern municipal sewage plant in southern Germany in March and June 1998. After solid phase extraction, total estrogenic activity was quantitatively measured with a miniaturized E-screen assay and the levels of nine estrogenic phenolic chemicals analyzed by HRGC/LRMS. 17Beta-estradiol equivalent concentrations (EEQ) were 58 and 70 ng/l in the influent and 6 ng/l in the effluent, indicating that the load of estrogenic activity of the wastewater was reduced by about 90% in the sewage plant. Less than 3% of the estrogenic activity was found in the sludge. 4-t-octylphenol, 4-nonylphenol, bisphenol A, 2-hydroxybiphenyl, and 4-chloro-3-methylphenol were detected in the untreated wastewater at levels from 0.13 to 3.6 microg/l. 4-t-octylphenol, 4-nonylphenol, and bisphenol A were present in the effluent at concentrations from 0.16 to 0.36 microg/l, 2-hydroxybiphenyl and 4-chloro-3-methylphenol were not detectable. The contribution of the quantified levels of phenolic xenoestrogens to total estrogenic activity in the sewage was 0.7-4.3%.

Identification and quantification of estrogenic compounds in recycled and virgin paper for household use as determined by an in vitro yeast estrogen screen and chemical analysis

The use of recycled paper for the manufacture of food contact materials is widespread, but very little is known about the presence of potential contaminants in the paper. The purpose of this study was to assess the worst-case migration of estrogenic active compounds using extracts of paper for household use. Twenty different brands of kitchen rolls, nine of which were made from recycled paper and the remainder from virgin paper, were obtained from retail shops. Paper extracts were subjected to (a) determination of the total estrogenic activity by using an in vitro estrogen screen based on yeast cells stably transfected with the human estrogen receptor alpha and (b) chemical analysis and quantification by GC/MS, GC/FTIR/MS, and GC/FID for detection of a variety of estrogenic compounds. A marked estrogenic response was observed in nine of the extracts, seven of which were made from recycled paper and two from virgin paper. The chemical analysis revealed that extracts made from recycled paper contained levels of bisphenol A ranging from 0.6 to 24 mg/kg of kitchen roll, whereas extracts from virgin paper contained no bisphenol A or only negligible amounts. In contrast, 4-tert-octylphenol, 4-nonylphenols, and di-n-butyl and diisobutyl phthalate were present to a varying degree in both recycled and virgin paper with no apparent preferable distribution between the two paper types. The estrogenic response of the two extracts made from virgin paper appeared to be due partly to the presence of the preservative propyl paraben. Diisopropylnaphthalene, which turned out to be weakly estrogenic active in vitro (EC(50) = 53 microM), was detected in minor amounts in most of the extracts with the major part, ranging from 0.3 to 4.7 mg/kg of paper, found in recycled paper. Our findings that recycled kitchen rolls contain bisphenol A and other xenoestrogens may apply to other types of recycled paper used for food packaging and emphasize the importance of identifying this and other contaminants in recycled paper in general. These data indicate that bisphenol A may be useful as a purity indicator for recycled paper.

Multidrug-resistant cancer cells are preferential targets of the new antineoplastic lanthanum compound KP772 (FFC24)

Recently, we have introduced [tris(1,10-phenanthroline)lanthanum(III)] trithiocyanate (KP772, FFC24) as a new lanthanum compound which has promising anticancer properties in vivo and in vitro. Aim of this study was to investigate the impact of ABC transporter-mediated multidrug resistance (MDR) on the anticancer activity of KP772. Here, we demonstrate that all MDR cell models investigated, overexpressing ABCB1 (P-glycoprotein), ABCC1 (multidrug resistance protein 1), or ABCG2 (breast cancer resistance protein) either due to drug selection or gene transfection, were significantly hypersensitive against KP772. Using ABCB1-overexpressing KBC-1 cells as MDR model, KP772 hypersensitivity was demonstrated to be based on stronger apoptosis induction and/or cell cycle arrest at unaltered cellular drug accumulation. KP772 did neither stimulate ABCB1 ATPase activity nor alter rhodamine 123 accumulation arguing against a direct interaction with ABCB1. Accordingly, several drug resistance modulators did not sensitize but rather protect MDR cells against KP772-induced cytotoxicity. Moreover, long-term KP772 treatment of KBC-1 cells at subtoxic concentrations led within 20 passages to a complete loss of drug resistance based on blocked MDR1 gene expression. When exposing parental KB-3-1 cells to subtoxic, stepwise increasing KP772 concentrations, we observed, in contrast to several other metallo-drugs, no acquisition of KP772 resistance. Summarizing, our data demonstrate that KP772 is hyperactive in MDR cells and might have chemosensitizing properties by blocking ABCB1 expression. Together with the disability of tumor cells to acquire KP772 resistance, our data suggest that KP772 should be especially active against notoriously drug-resistant tumor types and as second line treatment after standard chemotherapy failure.

Structure-Related Mode-of-Action Differences of Anticancer Organoruthenium Complexes with β-Diketonates

A series of organoruthenium(II) chlorido complexes with fluorinated O,O-ligands [(η(6)-p-cymene)Ru(F3C-acac-Ar)Cl] (1a-6a) and their respective 1,3,5-triaza-7-phosphaadamantane (pta) derivatives [(η(6)-p-cymene)Ru(F3C-acac-Ar)pta]PF6 (1b-6b) were synthesized and fully characterized in both solution and solid state. All complexes were inactive against nonmalignant keratinocytes but displayed variable activity against cancer cell models (ovarian, osteosarcoma). Compounds with a ligand containing the 4-chlorophenyl substituent (6a and 6b) exhibited the strongest anticancer effects. Despite a marginally lower cellular Ru accumulation compared to the chlorido complexes, pta analogues showed higher activity especially in the osteosarcoma model. Reduction of glutathione levels by buthionine sulfoximine (BSO) significantly enhanced the activity of all compounds with the most pronounced effects being observed for the pta series resulting in IC50 values down to the nanomolar range. While all chlorido complexes potently induce reactive oxygen species, DNA damage, and apoptosis, the respective pta compounds widely lacked ROS production but blocked cell cycle progression in G0/G1 phase.

Substances with estrogenic activity in effluents of sewage treatment plants in southwestern Germany. 1. Chemical analysis

A gas chromatography/mass spectrometry method for the simultaneous quantitative determination of natural and synthetic estrogens (17beta-estradiol, estrone, 17alpha-ethinylestradiol, and mestranol), phytoestrogens (genistein and beta-sitosterol), and xenoestrogens (benzyl butyl phthalate, dibutyl phthalate, bisphenol A, 4-nonylphenol [NP], 4-nonylphenoxyacetic acid [NP1EC], 4-nonylphenol diethoxylate [NP2EO], and alpha-endosulfan) in effluents of sewage treatment plants (STPs) was developed. Identification and quantification were carried out with the standard addition method using analyte-specific and, in some cases, deuterium-labeled internal standards. The effluents of 18 STPs were investigated. Apart from alpha-endosulfan and mestranol, all selected substances were detected in the majority of samples. The median concentrations of steroidal estrogens were between 0.4 ng/L (17alpha-ethinylestradiol) and 1.6 ng/L (17beta-estradiol). The metabolites of the nonylphenol polyethoxylates, NP, NPIEC, and NP2EO were found in concentrations ranging from the upper-ng/L-range (NP) to the lower-microg/L range (NP1EC). For all substances except mestranol and alpha-endosulfan, median values were calculated and compared to the results of other investigations in Europe and the United States. Possible dependencies of measured concentrations on the geographical location, the capacity, the influent composition, and the technical fitting of the STPs are discussed.

The ruthenium compound KP1339 potentiates the anticancer activity of sorafenib in vitro and in vivo

KP1339 is a promising ruthenium-based anticancer compound in early clinical development. This study aimed to test the effects of KP1339 on the in vitro and in vivo activity of the multi-kinase inhibitor sorafenib, the current standard first-line therapy for advanced hepatoma. Anticancer activity of the parental compounds as compared to the drug combination was tested against a panel of cancer cell lines with a focus on hepatoma. Combination of KP1339 with sorafenib induced in the majority of all cases distinctly synergistic effects, comprising both sorafenib-resistant as well as sorafenib-responsive cell models. Several mechanisms were found to underlie these multifaceted synergistic activities. Firstly, co-exposure induced significantly enhanced accumulation levels of both drugs resulting in enhanced apoptosis induction. Secondly, sorafenib blocked KP1339-mediated activation of P38 signalling representing a protective response against the ruthenium drug. In addition, sorafenib treatment also abrogated KP1339-induced G2/M arrest but resulted in check point-independent DNA-synthesis block and a complete loss of the mitotic cell populations. The activity of the KP1339/sorafenib combination was evaluated in the Hep3B hepatoma xenograft. KP1339 monotherapy led to a 2.4-fold increase in life span and, thus, was superior to sorafenib, which induced a 1.9-fold prolonged survival. The combined therapy further enhanced the mean survival by 3.9-fold. Synergistic activity was also observed in the VM-1 melanoma xenograft harbouring an activating braf mutation. Together, our data indicate that the combination of KP1339 with sorafenib displays promising activity in vitro and in vivo especially against human hepatoma models.

Intrinsic and acquired forms of resistance against the anticancer ruthenium compound KP1019 [indazolium trans-[tetrachlorobis(1H-indazole)ruthenate (III)] (FFC14A)

KP1019 [indazolium trans-[tetrachlorobis(1H-indazole)ruthenate (III)] (FFC14A) is a metal complex with promising anticancer activity. Since chemoresistance is a major obstacle in chemotherapy, this study investigated the influence of several drug resistance mechanisms on the anticancer activity of KP1019. Here we demonstrate that the cytotoxic effects of KP1019 are neither substantially hampered by overexpression of the drug resistance proteins multidrug resistance-related protein 1, breast cancer resistance protein, and lung resistance protein nor the transferrin receptor and only marginally by the cellular p53 status. In contrast, P-glycoprotein overexpression weakly but significantly (up to 2-fold) reduced KP1019 activity. P-glycoprotein-related resistance was based on reduced intracellular KP1019 accumulation and reversible by known P-glycoprotein modulators. KP1019 dose dependently inhibited ATPase activity of P-glycoprotein with a K(i) of approximately 31 microM. Furthermore, it potently blocked P-glycoprotein-mediated rhodamine 123 efflux under serum-free conditions (EC(50), approximately 8 microM), however, with reduced activity at increased serum concentrations (EC(50) at 10% serum, approximately 35 microM). Moreover, P-glycoprotein-mediated daunomycin resistance could only be marginally restored by KP1019 in serum-containing medium, also indicating an influence of serum proteins on the interaction between KP1019 and P-glycoprotein. Acquired KP1019 resistance was investigated by selecting KB-3-1 cells against KP1019 for more than 1 year. Only an approximately 2-fold KP1019 resistance could be induced, which unexpectedly was not due to overexpression of P-glycoprotein or other efflux pumps. Accordingly, KP1019-resistant cells did not display reduced drug accumulation. Their unique cross-resistance pattern confirmed an ABC transporter-independent resistance phenotype. In summary, the likeliness of acquiring insensitivity to KP1019 during therapy is expected to be low, and resistance should not be based on overexpression of drug efflux transporters.

Development of a sensitive E-screen assay for quantitative analysis of estrogenic activity in municipal sewage plant effluents

A simplified proliferation test with human estrogen receptor-positive MCF-7 breast cancer cells (E-screen assay) was optimized and validated for the sensitive quantitative determination of total estrogenic activity in effluent samples from municipal sewage plants. After solid phase extraction of 1 l sewage on either 0.2 g polystyrene copolymer (ENV+) or 1 g RP-C18 material and removal of the solvent, analysis of the extracts in the E-screen assay could be performed without any clean-up step. This was even possible with untreated sewage. Parallel extraction of four sewage samples on both different solid phase materials gave comparable quantitative results in the E-screen. A blank sample did not induce cell proliferation. As additive behaviour of the estrogenic response of single compounds was proven for two different mixtures each containing three xenoestrogens, total estrogenic activity in the sewage samples, expressed as 17 beta-estradiol equivalent concentration (EEQ), could be calculated comparing the EC50 values of the samples with those of the positive control 17 beta-estradiol. The detection limit of the E-screen method was 0.05 pmol EEQ/l (0.014 ng EEQ/l), the limit of quantification 0.25-0.5 pmol EEQ/l (0.07-0.14 ng EEQ/l). In total, extracts of nine effluent and one influent sample from five different municipal sewage plants in South Germany were analyzed in the E-screen. All samples strongly induced cell proliferation in a dose-dependent manner which was completely inhibited by coincubation with 5 nM of the estrogen receptor-antagonist ICI 182,780. The proliferative effect relative to the positive control 17 beta-estradiol (RPE) was between 30 and 101%. 17 beta-Estradiol equivalent concentrations were between 2.5 and 25 ng/l indicating a significant input of estrogenic substances via sewage treatment plants into rivers.

Development and validation of a GC/MS method for determination of phenolic xenoestrogens in aquatic samples

A simple and sensitive GC/MS method for the quantitative determination of the estrogenic phenolic compounds 4-nonylphenol, 4-t-octylphenol, bisphenol A, 3-t-butyl-4-hydroxyanisole, 2-t-butyl-4-methylphenol, 4-hydroxybiphenyl, 2-hydroxybiphenyl, 4-chloro-3-methylphenol, and 4-chloro-2-methylphenol in aquatic samples was developed. The method for assessing their occurrence in sewage, surface and drinking waters consists of solid phase extraction (SPE) using a polystyrene copolymer phase. After methylation of the extract HRGC/LRMS analysis was possible without any clean up, even in raw sewage samples. Limits of detection and determination were between <0.01 and 0.05 ng/l and 0.01 and 0.05 ng/l, respectively. Recoveries were above 70% with exception of 3-t-butyl-4-hydroxyanisole.

Anticancer activity of methyl-substituted oxaliplatin analogs

Oxaliplatin is successfully used in systemic cancer therapy. However, resistance development and severe adverse effects are limiting factors for curative cancer treatment with oxaliplatin. The purpose of this study was to comparatively investigate in vitro and in vivo anticancer properties as well as the adverse effects of two methyl-substituted enantiomerically pure oxaliplatin analogs [[(1R,2R,4R)-4-methyl-1,2-cyclohexanediamine] oxalatoplatinum(II) (KP1537), and [(1R,2R,4S)-4-methyl-1,2-cyclohexanediamine]oxalatoplatinum(II) (KP1691)] and to evaluate the impact of stereoisomerism. Although the novel oxaliplatin analogs demonstrated in multiple aspects activities comparable with those of the parental compound, several key differences were discovered. The analogs were characterized by reduced vulnerability to resistance mechanisms such as p53 mutations, reduced dependence on immunogenic cell death induction, and distinctly attenuated adverse effects including weight loss and cold hyperalgesia. Stereoisomerism of the substituted methyl group had a complex and in some aspects even contradictory impact on drug accumulation and anticancer activity both in vitro and in vivo. To summarize, methyl-substituted oxaliplatin analogs harbor improved therapeutic characteristics including significantly reduced adverse effects. Hence, they might be promising metal-based anticancer drug candidates for further (pre)clinical evaluation.

Validation and application of a rapid in vitro assay for assessing the estrogenic potency of halogenated phenolic chemicals

The E-Screen assay serves as an in vitro tool for the detection of estrogenic activity of chemicals and extracts of environmental samples. Based on the induction of proliferation in human estrogen receptor-positive MCF-7 breast cancer cells we could substantially simplify the assay. As one important step of validation we applied the modified assay for testing nine known xenoestrogens. We could confirm the results of other groups assuring the reproducibility of the E-Screen assay. The results provide evidence that the E-Screen assay is suitable for determination of estradiol equivalency factors (EEFs) for environmental estrogens to rank their estrogenic potency relative to the natural estrogen 17 beta-estradiol. Further, we used the optimized proliferation test to screen nine halogenated phenolic compounds for their possible estrogenic potency. Three widely applied chemicals expressed a weak receptor-mediated estrogenic activity: the flame retardant Tetrabromo-Bisphenol-A, the disinfectant 4-chloro-3-methylphenol, and the herbicide educt 4-chloro-2-methylphenol. Their estrogenic potencies were five to six orders of magnitude lower than that of 17 beta-estradiol.

Integrated Exposure Assessment Survey (INES)

The Integrated Exposure Assessment Survey (INES) was started in the year 2005. Altogether 50 healthy adults living in Bavaria, Germany, were included into the study. Monitoring was conducted in accordance with relevant routes of human exposure (inhalation, ingestion) and integrated different pathways (indoor air, food, house dust). This approach consisted of a combination of external measurements of contaminants with the determination of these substances or their metabolites in body fluids. The target substances were phthalates, perfluorinated compounds (PFC), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and polybrominated diphenylethers (PBDEs). This paper gives a brief description of the objectives and the concept of INES as well as methods of sampling and analyses of target compounds. Some preliminary results of biomonitoring data for PFC and phthalates as well as of the dietary intake of DEHP will be discussed.

Nanoformulation improves activity of the (pre)clinical anticancer ruthenium complex KP1019

Ruthenium anticancer drugs belong to the most promising non-platinum anticancer metal compounds in clinical evaluation. However, although the clinical results are promising regarding both activity and very low adverse effects, the clinical application is currently hampered by the limited solubility and stability of the drug in aqueous solution. Here, we present a new nanoparticle formulation based on polymer-based micelles loaded with the anticancer lead ruthenium compound KP1019. Nanoprepared KP1019 was characterised by enhanced stability in aqueous solutions. Moreover, the nanoparticle formulation facilitated cellular accumulation of KP1019 (determined by ICP-MS measurements) resulting in significantly lowered IC50 values. With regard to the mode of action, increased cell cycle arrest in G2/M phase (PI-staining), DNA damage (Comet assay) as well as enhanced levels of apoptotic cell death (caspase 7 and PARP cleavage) were found in HCT116 cells treated with the new nanoformulation of KP1019. Summarizing, we present for the first time evidence that nanoformulation is a feasible strategy for improving the stability as well as activity of experimental anticancer ruthenium compounds.

Effects of 2,3,7,8-tetrachloro- and 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin on the proliferation of preneoplastic liver cells in the rat

Using an initiation-promotion system, enzyme-altered putative preneoplastic liver foci were induced in female Wistar rats by application of diethylnitrosamine (10 mg/kg/day) for 5 days, followed by bi-weekly treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; corresponding to 100 ng/kg/day) or 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HCDD; corresponding to 5 micrograms/kg/day) for up to 17 weeks. Groups of animals were killed at various time intervals after start of promoter treatment. For evaluation of DNA synthesis, 5-bromo-2'-deoxyuridine was administered 24 h prior to killing the animals. Quantitative analysis of the number and volume fraction of adenosine-triphosphatase-deficient liver foci revealed that the promoting activity of both dioxins was roughly comparable under the experimental conditions employed. Nuclear labelling indices (LIs) of normal hepatocytes were not altered by TCDD or HCDD treatment, while a slight increase in LIs of non-parenchymal liver cells was observed. Using an immunohistochemical double-staining technique, hepatocytes within glutathione-transferase P-positive liver foci were found to show an approximately 5-to 10-fold higher LI than normal hepatocytes throughout all periods of investigation. During the time course of the experiment, LIs of foci from all treatment groups decreased with time. However, in TCDD-treated rats, and less pronounced in HCDD-treated rats, the initially high rate of proliferation persisted for a greater length of time than in non-dioxin-treated control animals. Assignment of liver foci into four transection size classes revealed that LIs in larger size classes varied considerably, indicating heterogeneity in the growth behaviour of individual liver lesions. Overall, both dioxins had no effects on the proliferation of normal hepatocytes, while LIs of enzyme-altered liver lesions were slightly enhanced by treatment with TCDD or HCDD. Whether the selective, albeit moderate increase in the proliferation of enzyme-altered liver cells is sufficient to explain the promoting activity of dioxins, or if additional factors (e.g. decrease in death rates of foci cells) are equally important, remains to be determined in further experiments.

Fish as bioindicators for trace element pollution from two contrasting lakes in the Eastern Rift Valley, Kenya: spatial and temporal aspects

Lake Turkana and Lake Naivasha are two freshwater lakes in the Kenyan Rift Valley that differ significantly in water chemistry and anthropogenic influence: Lake Turkana is believed to be rather pristine and unpolluted, but a previous study has shown rather high levels of Li, Zn, and Cd in the migratory fish species Hydrocynus forskahlii, questioning this pristine status. Lake Naivasha is heavily influenced by agricultural activity in its catchment area and by direct water use, and high levels of metal pollutants have been reported in fish. This study presents the distribution of nine important trace elements in liver and muscle of the nonmigratory red belly tilapia Tilapia zillii from Lake Turkana and from Lake Naivasha (before and after a significant rise in water level due to as yet not fully understood reasons). In addition, trace element levels in the common carp Cyprinus carpio from Lake Naivasha are presented. Metal concentrations measured in the liver and muscle of T. zillii collected in Lake Turkana confirm the pristine status of the study site, but contrast with the results obtained for the migratory H. forskahlii. Comparing T. zillii from the two lakes reveals a clear difference in accumulation patterns between essential and nonessential trace elements: physiologically regulated essential elements are present in a very similar range in fish from both lakes, while levels of nonessential metals reflect short- or long-term exposure to those elements. The comparison of trace element concentrations in the fish samples from Lake Naivasha showed lower levels of most trace elements after the significant increase of the water level. This study demonstrates that fish are valuable bioindicators for evaluating trace element pollution even in contrasting lakes as long as the way-of-life habits of the species are taken into account.

[Air quality in schools - classroom levels of carbon dioxide (CO2), volatile organic compounds (VOC), aldehydes, endotoxins and cat allergen]

Children are assumed to be more vulnerable to health hazards and spend a large part of their time in schools. To assess the exposure situation in this microenvironment, we evaluated the indoor air quality in winter 2004/5 in 92 classrooms, and in 75 classrooms in summer 2005 in south Bavaria, Germany. Indoor air climate parameters (temperature, relative humidity), carbon dioxide (CO2) and various volatile organic compounds, aldehydes and ketones were measured. Additionally, cat allergen (Fel d1) and endotoxin (LAL-test) were analysed in the settled dust of school rooms. Data on room and building characteristics were collected by use of a standardised form. Only data collected during teaching hours were considered in analysis. The median indoor CO2 concentration in the classrooms ranged in the winter and summer period from 598 to 4 172 ppm and 480 to 1 875 ppm, respectively. While during the winter period in 92% of the classrooms the CO2 daily medians went above 1 000 ppm, the percentage of classrooms with increased CO2 concentration fell to 28% in summer. In winter, in 60% of classes the daily median CO2 concentration exceeded 1 500 ppm, while in summer this threshold was reached by only 9%. A high concentration of CO2 was associated with a high number of pupils, a low room surface area and a low room volume. The levels of total volatile organic compounds (TVOC) in classrooms ranged between 110 and 1 000 microg/m3 (median in winter 345 microg/m3, in summer 260 microg/m3). Acetone, formaldehyde and acetaldehyde were measured in concentrations from 14.0 to 911 microg/m3, from 3.1 to 46.1 microg/m3, and from 2.9 to 78 microg/m3, respectively. The other aldehydes were detected in minor amounts only. The median Fel d1 level in winter was 485 ng/g dust (20 to 45 160 ng/g) and in summer it was 417 ng/g (40-7 470 ng/g). We observed no marked differences between the two sampling periods and between smooth floors and rooms with carpeted floors. No differences were found according to room surface area and room volume. The median endotoxin contents in winter and summer were 19.7 EU/mg dust (6.6 to 154 EU/mg) and 32.2 EU/mg (9.6 to 219 EU/mg), respectively. The levels varied significantly between the sampling periods, but were independent of room surface area, room volume and surface floorings. Overall the results of VOC, aldehydes, ketones and endotoxin indicate, in general, a low exposure level in classrooms. The observed concentrations of cat allergens should be considered as a meaningful exposure route and thus could be tackled within preventive programs.

Macromolecular Pt(IV) Prodrugs from Poly(organo)phosphazenes

The preparation of novel macromolecular prodrugs via the conjugation of two platinum(IV) complexes to suitably functionalized poly(organo)phosphazenes is presented. The inorganic/organic polymers provide carriers with controlled dimensions due to the use of living cationic polymerization and allow the preparation of conjugates with excellent aqueous solubility but long-term hydrolytic degradability. The macromolecular Pt(IV) prodrugs are designed to undergo intracellular reduction and simultaneous release from the macromolecular carrier to present the active Pt(II) drug derivatives. In vitro investigations show a significantly enhanced intracellular uptake of Pt for the macromolecular prodrugs when compared to small molecule Pt complexes, which is also reflected in an increase in cytotoxicity. Interestingly, drug-resistant sublines also show a significantly smaller resistance against the conjugates compared to clinically established platinum drugs, indicating that an alternative uptake route of the Pt(IV) conjugates might also be able to overcome acquired resistance against Pt(II) drugs. In vivo studies of a selected conjugate show improved tumor shrinkage compared to the respective Pt(IV) complex.

Major and trace element geochemistry of Lake Bogoria and Lake Nakuru, Kenya, during extreme draught

The physico-chemical properties of water samples from the two athalassic endorheic lakes Bogoria and Nakuru in Kenya were analysed. Surface water samples were taken between July 2008 and October 2009 in weekly intervals from each lake. The following parameters were determined: pH, salinity, electric conductivity, dissolved organic carbon (DOC), the major cations (FAAS and ICP-OES) and the major anions (IC), as well as certain trace elements (ICP-OES). Samples of superficial sediments were taken in October 2009 and examined using Instrumental Neutron Activation Analysis (INAA) for their major and trace element content including rare earth elements (REE). Both lakes are highly alkaline with a dominance of Na > K > Si > Ca in cations and HCO3 > CO3 > Cl > F > SO4 in anions. Both lakes also exhibited high concentrations of Mo, As and fluoride. Due to an extreme draught from March to October 2009, the water level of Lake Nakuru dropped significantly. This created drastic evapoconcentration, with the total salinity rising from about 20‰ up to 63‰. Most parameters (DOC, Na, K, Ca, F, Mo and As) increased with falling water levels. A clear change in the quality of DOC was observed, followed by an almost complete depletion of dissolved Fe from the water phase. In Lake Bogoria the evapoconcentration effects were less pronounced (total salinity changed from about 40‰ to 48‰). The distributions of REE in the superficial sediments of Lake Nakuru and Lake Bogoria are presented here for the first time. The results show a high abundance of the REE and a very distinct Eu depletion of Eu/Eu* = 0.33-0.45.

Selective modulation of ER-beta by estradiol and xenoestrogens in human breast cancer cell lines

In the last decades, substances with estrogenic activity have been dispersed into the environment. Xenoestrogens act by binding to estrogen receptors, ligand-regulated transcription factors, for which two subtypes have been described, ER-alpha and ER-beta, which are often coexpressed at variable amounts in different tissues. We investigated variations in the expression of ER-alpha and ER-beta mRNAs following treatment with four xenoestrogens (bisphenol A, 4-tert octylphenol, 2-hydroxybiphenyl, 4-hydroxybiphenyl) and with 17beta-estradiol in estrogen-sensitive (T47D) and estrogen-insensitive (BT20) breast cancer cell lines. Although to a variable extent, both estradiol and the tested xenoestrogens increased the expression of ER-beta mRNA, whereas a slight effect on ER-alpha was observed only in T47D cells. Upregulation of ER-beta expression by estradiol and xenoestrogens was observed only in the presence of detectable ER-alpha protein levels. These findings indicate a regulatory role for ER-beta in ER-alpha-mediated transcription and a role for ER-beta in mediating xenoestrogen toxicity.