11 results on '"Heger S"'
Search Results
2. A plea for the integration of Green Toxicology in sustainable bioeconomy strategies - Biosurfactants and microgel-based pesticide release systems as examples.
- Author
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Johann S, Weichert FG, Schröer L, Stratemann L, Kämpfer C, Seiler TB, Heger S, Töpel A, Sassmann T, Pich A, Jakob F, Schwaneberg U, Stoffels P, Philipp M, Terfrüchte M, Loeschcke A, Schipper K, Feldbrügge M, Ihling N, Büchs J, Bator I, Tiso T, Blank LM, Roß-Nickoll M, and Hollert H
- Subjects
- Animals, Ecotoxicology, Fishes, Hazardous Substances, Humans, Microgels, Pesticides toxicity
- Abstract
A key aspect of the transformation of the economic sector towards a sustainable bioeconomy is the development of environmentally friendly alternatives for hitherto used chemicals, which have negative impacts on environmental health. However, the implementation of an ecotoxicological hazard assessment at early steps of product development to elaborate the most promising candidates of lowest harm is scarce in industry practice. The present article introduces the interdisciplinary proof-of-concept project GreenToxiConomy, which shows the successful application of a Green Toxicology strategy for biosurfactants and a novel microgel-based pesticide release system. Both groups are promising candidates for industrial and agricultural applications and the ecotoxicological characterization is yet missing important information. An iterative substance- and application-oriented bioassay battery for acute and mechanism-specific toxicity within aquatic and terrestrial model species is introduced for both potentially hazardous materials getting into contact with humans and ending up in the environment. By applying in silico QSAR-based models on genotoxicity, endocrine disruption, skin sensitization and acute toxicity to algae, daphnids and fish, individual biosurfactants resulted in deviating toxicity, suggesting a pre-ranking of the compounds. Experimental toxicity assessment will further complement the predicted toxicity to elaborate the most promising candidates in an efficient pre-screening of new substances., (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Published
- 2022
- Full Text
- View/download PDF
3. Endocrine-disrupting chemicals and their effects on puberty.
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Lopez-Rodriguez D, Franssen D, Heger S, and Parent AS
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- Animals, Female, Humans, Male, Obesity chemically induced, Obesity epidemiology, Obesity genetics, Puberty, Sexual Maturation, Endocrine Disruptors toxicity, Puberty, Precocious chemically induced, Puberty, Precocious epidemiology, Puberty, Precocious genetics
- Abstract
Sexual maturation in humans is characterized by a unique individual variability. Pubertal onset is a highly heritable polygenic trait but it is also affected by environmental factors such as obesity or endocrine disrupting chemicals. The last 30 years have been marked by a constant secular trend toward earlier age at onset of puberty in girls and boys around the world. More recent data, although more disputed, suggest an increased incidence in idiopathic central precocious puberty. Such trends point to a role for environmental factors in pubertal changes. Animal data suggest that the GnRH-neuronal network is highly sensitive to endocrine disruption during development. This review focuses on the most recent data regarding secular trend in pubertal timing as well as potential new epigenetic mechanisms explaining the developmental and transgenerational effects of endocrine disrupting chemicals on pubertal timing., Competing Interests: Declaration of competing interest The authors have no conflict of interest to declare., (Copyright © 2021 Elsevier Ltd. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
4. Evaluation of chloride contributions from major point and nonpoint sources in a northern U.S. state.
- Author
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Overbo A, Heger S, and Gulliver J
- Abstract
Chloride pollution of groundwater and surface water resources is an environmental concern in many regions. While use of road salt for winter road maintenance is known to be a major source of chloride in the environment, limited research has investigated the environmental impacts of chloride discharged from water softeners, particularly in areas with hard water. A chloride budget was developed for the state of Minnesota to estimate the amount of chloride discharged from household water softeners as well as other domestic, agricultural, commercial, and industrial sources. The analysis used multiple data sources, including salt sales records and wastewater monitoring data, and used statistical, spatial, and survey methods to estimate chloride loading from major sources statewide. Annual chloride mass contributions were estimated for the following sources: household water softener use; human excretions; household product use; chloride concentrations in drinking water; atmospheric deposition; road salt use; dust suppressant use; fertilizer application; industrial discharge; and livestock excretions. A mass balance for 96 wastewater treatment plants with effluent monitoring data showed that across these facilities, discharge from water softeners was the largest chloride source. A statewide chloride budget found that road salt was the largest source of chloride to the environment, but that WWTPs and fertilizer were also substantial sources, discharging 221,300 t and 209,900 t annually. Water softeners were estimated to contribute 65% of the chloride discharged to all 613 municipal WWTPs statewide. Methods used in this analysis could be applied to other communities, watersheds, or states with similar conditions. The results of the analyses indicate that water softening is an important chloride source in areas with hard water and underscore the importance of identifying and characterizing chloride sources in less urban areas, where deicing salt may be a less important contributor and receiving water bodies are often lakes, reservoirs, and streams., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
5. Green toxicological investigation for biofuel candidates.
- Author
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Heger S, Brendt J, Hollert H, Roß-Nickoll M, and Du M
- Subjects
- Animals, Cell Line, Cricetinae, Daphnia, Humans, Toxicity Tests, Acute, Zebrafish, Biofuels toxicity, Water Pollutants, Chemical
- Abstract
To avoid potential risks of biofuels on the environment and human, ecotoxicity investigation should be integrated into the early design stage for promising biofuel candidates. In the present study, a green toxicology testing strategy combining experimental bioassays with in silico tools was established to investigate the potential ecotoxicity of biofuel candidates. Experimental results obtained from the acute immobilisation test, the fish embryo acute toxicity test and the in vitro micronucleus assay (Chinese hamster lung fibroblast cell line V79) were compared with model prediction results by ECOSAR and OECD QSAR Toolbox. Both our experimental and model prediction results showed that 1-Octanol (1-Oct) and Di-n-butyl ether (DNBE) were the most toxic to Daphnia magna and zebrafish among all the biofuel candidates we investigated, while Methyl ethyl ketone (MEK), Dimethoxymethane (DMM) and Diethoxymethane (DEM) were the least toxic. Moreover, both in vitro micronucleus assay and OECD QSAR Toolbox evaluation suggested that the metabolites present higher genotoxicity than biofuel candidates themselves. Overall, our results proved that this green toxicology testing strategy is a useful tool for assessing ecotoxicity of biofuel candidates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2021
- Full Text
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6. Using a high-throughput method in the micronucleus assay to compare animal-free with rat-derived S9.
- Author
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Brendt J, Lackmann C, Heger S, Velki M, Crawford SE, Xiao H, Thalmann B, Schiwy A, and Hollert H
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- Animals, Cell Line, Cricetinae, Cyclophosphamide, Micronucleus Tests, Rats, Benzo(a)pyrene, Mutagens toxicity
- Abstract
This study presents a high-throughput (HTP) micronucleus assay in multi-well plates with an automated evaluation for risk assessment applications. The evaluation of genotoxicity via the micronucleus assays according to international guidelines ISO 21427-2 with Chinese hamster (Cricetulus griseus) V79 cells was the starting point to develop our methodology. A drawback of this assay is that it is very time consuming and cost intensive. Our HTP micronucleus assay in a 48-well plate format allows for the simultaneous assessment of five different sample-concentrations with additional positive, negative and solvent controls with six technical replicates each within a quarter of the time required for the equivalent evaluation using the traditional slide method. In accordance with the 3R principle, animal compounds should be replaced with animal-free alternatives. However, traditional cell culture-based methods still require animal derived compounds like rat-liver derived S9-fraction, which is used to simulate the mammalian metabolism in in vitro assays that do show intrinsic metabolization capabilities. In the present study, a recently developed animal-free biotechnological alternative (ewoS9R) was investigated in the new high-throughput micronucleus assay. In total, 12 different mutagenic or genotoxic chemicals were investigated to assess the potential use of the animal-free metabolization system (ewoS9R) in comparison to a common rat-derived product. Out of the 12 compounds, one compound did not induce micronuclei in any treatment and 2 substances showed a genotoxic potential without the need for a metabolization system. EwoS9R demonstrated promising potential for future applications as it shows comparable results to the rat-derived S9 for 6 of the 9 pro-genotoxic substances tested. The remaining 3 substances (2-Acetamidofluorene, Benzo[a]pyrene, Cyclophosphamide) were only metabolized by rat-derived S9. A potential explanation is that ewoS9R was investigated with an approx. 10-fold lower enzyme concentration and was only optimized for CYP1A metabolization that may be improved with a modified production procedure. Future applications of ewoS9R go beyond the micronucleus assay, but further research is necessary., Competing Interests: Declaration of competing interest Beat Thalmann, Andreas Schiwy and Henner Hollert co-founder of EWOMIS GmbH, a company aimed to commercialize biotechnological metabolization systems., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2021
- Full Text
- View/download PDF
7. Aquatic toxicity of biofuel candidates on Daphnia magna.
- Author
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Heger S, Bluhm K, Du M, Lehmann G, Anders N, Dechambre D, Bardow A, Schäffer A, and Hollert H
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- Animals, Biological Assay, Furans toxicity, Reproduction drug effects, Toxicity Tests, Acute, Water Pollutants, Chemical toxicity, Biofuels toxicity, Daphnia drug effects
- Abstract
The increasing need for carbon-neutral, low-emission transportation sector has led to the development of advanced biofuels with tailor-made production and combustion processes. Even though the large-scale deployment of these advanced biofuels also increases the risk for their release into the environment, their toxic potency remains largely unknown. To identify hazardous biofuel candidates as early as possible, the fuel development process can be expanded by "Green Toxicology". To demonstrate such early Green Toxicology testing, this study investigates the aquatic toxicity for the two biofuel candidates 2-methyltetrahydrofuran (2-MTHF) and 2-methylfuran (2-MF) on Daphnia magna. We performed the prolonged acute immobilisation assay (96 h) and the D. magna reproduction test. 2-MF induced acute effects on D. magna that were two orders of magnitude stronger than those of 2-MTHF. Furthermore, both substances affected the growth and reproductive output of D. magna in a 21 d reproduction test, with 2-MF already inducing effects with concentrations one to two orders of magnitude lower than those of 2-MTHF. Thus, our assessment of the aquatic toxicity suggests that further biofuel development should focus on 2-MTHF. Furthermore, the acute immobilisation test with D. magna was identified as a promising tool for a rapid and sensitive "Green Toxicology" screening of further biofuel candidates., (Copyright © 2018 Elsevier Inc. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
8. Comparative ecotoxicity of potential biofuels to water flea (Daphnia magna), zebrafish (Danio rerio) and Chinese hamster (Cricetulus griseus) V79 cells.
- Author
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Heger S, Du M, Bauer K, Schäffer A, and Hollert H
- Subjects
- Animals, Cell Line, Cricetinae, Ecotoxicology, Zebrafish embryology, Biofuels toxicity, Daphnia drug effects, Embryo, Nonmammalian drug effects, Toxicity Tests, Acute
- Abstract
The ecotoxicity of two biofuel candidates (1‑octanol and 2‑butanone) was investigated by an integrative test strategy using three bioassays: the acute immobilisation test with water flea (D. magna), the fish embryo acute toxicity test with zebrafish (Danio rerio) and the in vitro micronucleus assay with Chinese hamster (Cricetulus griseus) V79 cells. The median effective concentration (EC
50 ) values were 14.9±0.66mgL-1 for 1‑octanol, and 2152.1±44.6mgL-1 for 2‑butanone in the D. magna test. Both 1‑octanol and 2‑butanone caused teratogenic and lethal effects on zebrafish embryos, while exposure to 1‑octanol significantly induced these effects at concentrations ≥2.0mgL-1 . These results indicate that 1‑octanol exert much higher ecotoxicity than 2‑butanone to D. magna and zebrafish embryos. Moreover, both 1‑octanol and 2‑butanone did not cause significant genotoxic effects, while their metabolites significantly induced micronuclei in V79 cells. The present study proposed an integrative test approach to evaluate the potential ecotoxicity of biofuels using simple, quick and inexpensive bioassays., (Copyright © 2018 Elsevier B.V. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
9. Recent advances of ultrasound imaging in dentistry--a review of the literature.
- Author
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Marotti J, Heger S, Tinschert J, Tortamano P, Chuembou F, Radermacher K, and Wolfart S
- Subjects
- Humans, Ultrasonography methods, Dentistry methods, Stomatognathic Diseases diagnostic imaging
- Abstract
Ultrasonography as an imaging modality in dentistry has been extensively explored in recent years due to several advantages that diagnostic ultrasound provides. It is a non-invasive, inexpensive, painless method and unlike X-ray, it does not cause harmful ionizing radiation. Ultrasound has a promising future as a diagnostic imaging tool in all specialties in dentistry, for both hard and soft tissue detection. The aim of this review is to provide the scientific community and clinicians with an overview of the most recent advances of ultrasound imaging in dentistry. The use of ultrasound is described and discussed in the fields of dental scanning, caries detection, dental fractures, soft tissue and periapical lesions, maxillofacial fractures, periodontal bony defects, gingival and muscle thickness, temporomandibular disorders, and implant dentistry., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
- Full Text
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10. Satoyoshi syndrome: a rare multisystemic disorder requiring systemic and symptomatic treatment.
- Author
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Heger S, Kuester RM, Volk R, Stephani U, and Sippell WG
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- Adult, Bone Diseases, Developmental complications, Bone Diseases, Developmental drug therapy, Carbamazepine therapeutic use, Drug Therapy, Combination, Female, Glucocorticoids therapeutic use, Humans, Immunosuppressive Agents therapeutic use, Prednisolone therapeutic use, Steroids therapeutic use, Endocrine System Diseases complications, Endocrine System Diseases drug therapy, Spasm complications, Spasm drug therapy
- Abstract
Satoyoshi syndrome is a rare multisystemic disorder with assumed autoimmune pathogenesis. Typical clinical features are progressive painful muscle spasms, alopecia, diarrhoea, and skeletal and endocrine abnormalities often resulting in early invalidism and death. Patients have been treated with immunoglobulins and glucocorticoids with varying outcome. We report on a 19-year-old German adolescent who has been successfully treated with a new combination of carbamazepine to reduce the severity and frequency of painful nocturnal muscle spasms, prednisolone, methotrexate and sex-steroids. Prednisolone treatment alone was not successful. After introduction of low-dose of methotrexate to the therapy the patient recovered from muscle spasms, alopecia and diarrhoea. Initiation of sex-steroid treatment resulted in pubertal development, regular menstrual cycles and improved quality of life.
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- 2006
- Full Text
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11. Labour-associated expression of intercellular adhesion molecule-1 (ICAM-1) in placental endothelial cells indicates participation of immunological processes in parturition.
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Steinborn A, Sohn C, Heger S, Niederhut A, Hildenbrand R, and Kaufmann M
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- Adult, Cesarean Section, Female, Humans, Immunohistochemistry, Obstetric Labor, Premature metabolism, Pregnancy, Trophoblasts chemistry, Umbilical Cord chemistry, Endothelium, Vascular chemistry, Intercellular Adhesion Molecule-1 analysis, Labor, Obstetric metabolism, Placenta blood supply
- Abstract
Inflammatory cytokines induce or upregulate de novo expression of cell adhesion molecules on endothelial and epithelial cells. In order to demonstrate inflammatory reactions within placental tissues in association with normal term as well as non-infection-induced preterm labour, the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelial leucocyte adhesion molecule-1 (ELAM-1) was examined by immunohistochemical methods in both trophoblastic villi (n=123) and umbilical cord (n=61). As a result, ICAM-1 immunoreactivity was exclusively localized in the endothelial cells of the fetal vascular system, while VCAM-1 and ELAM-1 were not detected. Whereas ICAM-1 was not expressed in early pregnancy (9-12 weeks of gestation), it could be weakly detected at the end of pregnancy in cases of elective caesarean delivery in the absence of labour, and was significantly more strongly expressed in cases of vaginal delivery after spontaneous onset of normal term labour. Significantly increased immunoreactivity of ICAM-1 within umbilical cord tissues was also found in association with uncontrollable preterm labour in the absence of intrauterine infection which was excluded after histological examination of fetal membranes, umbilical cord and chorionic plate. We conclude that ICAM-1 expression in the endothelium of the fetal vascular system is associated with the presence of labour and reflects participation of immune-inflammatory reactions in labour-promoting mechanisms., (Copyright 1999 Harcourt Publishers Ltd.)
- Published
- 1999
- Full Text
- View/download PDF
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