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Zercher M, Coral JA, Nabb D, Powers G, Jones A, Johanning K. A Comparison of In Vitro Metabolic Clearance of Various Regulatory Fish Species Using Hepatic S9 Fractions. Environ Toxicol Chem 2024. [PMID: 38652000 DOI: 10.1002/etc.5866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 09/04/2023] [Accepted: 03/08/2024] [Indexed: 04/25/2024]
Abstract
Bioaccumulation predictions can be substantially improved by combining in vitro metabolic rate measurements derived from rainbow trout hepatocytes and/or hepatic S9 fractions with quantitative structure-activity relationship (QSAR) modeling approaches. Compared with in vivo testing guidelines Organisation for Economic Co-operation and Development (OECD) 305 and Office of Chemical Safety and Pollution Prevention (OCSPP; an office of the US Environmental Protection Agency) 850.1730, the recently adopted OECD test guidelines 319A and 319B are in vitro approaches that have the potential to provide a time- and cost-efficient, humane solution, reducing animal use while addressing uncertainties in bioaccumulation across species. The present study compares the hepatic clearance of the S9 subcellular fraction of rainbow trout, bluegill, common carp, fathead minnow, and largemouth bass, discerning potential differences in metabolism between different warm- and cold-water species. With refinements to the in vitro metabolic S9 assay for high-throughput analysis, we measured in vitro clearance rates of seven chemicals crossing multiple classes of chemistry and modes of action. We confirmed that data from rainbow trout liver S9 fraction metabolic rates can be utilized to predict rainbow trout bioconcentration factors using an in vitro to in vivo extrapolation model, as intended in the OECD 319B applicability domain per the bioaccumulation prediction. Also, we determined that OECD 319B can be applied to other species, modified according to their habitat, adaptations to feeding behavior, and environmental conditions (e.g., temperature). Once toxicokinetics for each species is better understood and appropriate models are developed, this method can be an excellent tool to determine hepatic clearance and potential bioaccumulation across species. The present study could be leveraged prior to or in place of initiating in vivo bioconcentration studies, thus optimizing selection of appropriate fish species. Environ Toxicol Chem 2024;00:1-16. © 2024 SETAC.
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Affiliation(s)
| | | | - Diane Nabb
- FMC Agricultural Solutions, Newark, Delaware, USA
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2
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Jansen G, Latka E, Deicke M, Fischer D, Gretenkort P, Hoyer A, Keller Y, Kobiella A, Ristau P, Seewald S, Strickmann B, Thies KC, Johanning K, Tiesmeier J. [Prehospital postcardiac-arrest-sedation and -care in the Federal Republic of Germany-a web-based survey of emergency physicians]. Med Klin Intensivmed Notfmed 2023:10.1007/s00063-023-01056-1. [PMID: 37682284 DOI: 10.1007/s00063-023-01056-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/12/2023] [Accepted: 07/24/2023] [Indexed: 09/09/2023]
Abstract
BACKGROUND This study evaluates the implementation of postcardiac-arrest-sedation (PCAS) and -care (PRC) by prehospital emergency physicians in Germany. MATERIALS AND METHODS Analysis of a web-based survey from October to November 2022. Questions were asked about implementation, medications used, complications, motivation for implementing or not implementing PCAS, and measures and target parameters of PRC. RESULTS A total of 500 emergency physicians participated in the survey. In all, 73.4% stated that they regularly performed PCAS (hypnotics: 84.7%; analgesics: 71.1%; relaxants: 29.7%). Indications were pressing against the respirator (88.3%), analgesia (74.1%), synchronization to respirator (59.5%), and change of airway device (52.6%). Reasons for not performing PCAS (26.6%) included unconscious patients (73.7%); concern about hypotension (31.6%), re-arrest (26.3%), and worsening neurological assessment (22.5%). Complications of PCAS were observed by 19.3% of participants (acute hypotension [74.6%]); (re-arrest [32.4%]). In addition to baseline monitoring, PRC included 12-lead-electrocardiogram (96.6%); capnography (91.6%); catecholamine therapy (77.6%); focused echocardiography (20.6%), lung ultrasound (12.0%) and abdominal ultrasound (5.6%); induction of hypothermia (13.6%) and blood gas analysis (7.4%). An etCO2 of 35-45 mm Hg was targeted by 40.6%, while 9.0% of participants targeted an SpO2 of 94-98% and 19.2% of participants targeted a systolic blood pressure of ≥ 100 mm Hg. CONCLUSIONS Prehospital PRC in Germany is heterogeneous and deviations from its target parameters are frequent. PCAS is frequent and associated with relevant complications. The development of preclinical care algorithms for PCAS and PRC within preclinical care seems urgently needed.
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Affiliation(s)
- G Jansen
- Universitätsklinikum für Anästhesiologie, Intensiv- und Notfallmedizin der Ruhr-Universität Bochum, Johannes Wesling Klinikum Minden, Minden, Deutschland.
- Universität Bielefeld, Medizinische Fakultät OWL, Universitätsstr. 25, 33615, Bielefeld, Deutschland.
- Fachbereich Medizin und Rettungswesen, Studieninstitut Westfalen-Lippe, Bielefeld, Deutschland.
| | - E Latka
- Fachbereich Medizin und Rettungswesen, Studieninstitut Westfalen-Lippe, Bielefeld, Deutschland
| | - M Deicke
- Ärztliche Leitung Rettungsdienst Landkreis Osnabrück, Osnabrück, Deutschland
| | - D Fischer
- Ärztliche Leitung Rettungsdienst Kreis Lippe, Detmold, Deutschland
| | - P Gretenkort
- Simulations- und Notfallakademie am Helios Klinikum Krefeld, Helios Klinikum Krefeld, Krefeld, Deutschland
| | - A Hoyer
- Biostatistik und Medizinische Biometrie, Medizinische Fakultät OWL, Universität Bielefeld, Bielefeld, Deutschland
| | - Y Keller
- Integrierte Regionalleitstelle Dresden, Geschäftsbereich Ordnung und Sicherheit, Brand- und Katastrophenschutzamt, Landeshauptstadt Dresden, Dresden, Deutschland
| | - A Kobiella
- Ärztliche Leitung Rettungsdienst Kreis Gütersloh, Gütersloh, Deutschland
| | - P Ristau
- Institut für Rettungs- und Notfallmedizin (IRuN), Universitätsklinikum Schleswig-Holstein, Kiel, Deutschland
| | - S Seewald
- Institut für Rettungs- und Notfallmedizin (IRuN), Universitätsklinikum Schleswig-Holstein, Kiel, Deutschland
- Klinik für Anästhesiologie und Operative Intensivmedizin, Universitätsklinikum Schleswig-Holstein - Campus Kiel, Kiel, Deutschland
| | - B Strickmann
- Ärztliche Leitung Rettungsdienst Kreis Gütersloh, Gütersloh, Deutschland
| | - K C Thies
- Universitätsklinik für Anästhesiologie, Intensiv‑, Notfallmedizin, Transfusionsmedizin und Schmerztherapie, Universitätsklinikum OWL der Universität Bielefeld, Evangelisches Klinikum Bielefeld, Bielefeld, Deutschland
| | - K Johanning
- Klinik für Anästhesiologie, operative Intensivmedizin, Notfallmedizin und Schmerztherapie, Universitätsklinikum OWL der Universität Bielefeld - Campus Klinikum Bielefeld, Bielefeld, Deutschland
| | - J Tiesmeier
- Institut für Anästhesiologie, Intensiv- und Notfallmedizin, MKK - Krankenhaus Lübbecke, Campus OWL der Ruhr-Universität Bochum, Lübbecke, Deutschland
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3
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Franco ME, Johanning K, Matson CW, Lavado R. Reduced biotransformation of polycyclic aromatic hydrocarbons (PAHs) in pollution-adapted Gulf killifish (Fundulus grandis). Sci Total Environ 2022; 806:150854. [PMID: 34655636 DOI: 10.1016/j.scitotenv.2021.150854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/22/2021] [Accepted: 10/03/2021] [Indexed: 06/13/2023]
Abstract
Anthropogenic pollution represents a significant source of selection, potentially leading to the emergence of evolutionary adaptations in chronically exposed organisms. A recent example of this scenario corresponds to Gulf killifish (Fundulus grandis) populations inhabiting the Houston Ship Channel (HSC), Texas, USA, which have been documented to have adapted to this heavily contaminated environment. Although not fully elucidated, one particularly important aspect of their adaptation involves the reduced inducibility of the aryl hydrocarbon receptor (AhR) and, potentially, the alteration of major biotransformation pathways. In the present study, we employed a modified Organization for Economic Cooperation and Development (OECD) 319-B test guideline to explore population and sex-related differences in the hepatic biotransformation of six polycyclic aromatic hydrocarbons (PAHs) in F. grandis populations with different exposure histories. Pollution-adapted F. grandis showed significantly lower hepatic clearance of PAHs than non-adapted fish, especially for high molecular weight PAHs (chrysene, benzo[k]fluoranthene, and benzo[a]pyrene), with pollution-adapted females presenting the lowest clearance. The characterization of different phase I biotransformation enzymes revealed that the basal activity of CYP1A, fundamental in the biotransformation of PAHs, was significantly lower in pollution-adapted fish, especially in females, which showed the lowest activity. Contrarily, basal CYP2C9-like activity was significantly higher in pollution-adapted fish. These results demonstrate the importance of exposure and evolutionary histories in shaping organisms' responses to pollution and provide significant evidence of sex-specific biotransformation differences in F. grandis populations.
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Affiliation(s)
- Marco E Franco
- Department of Environmental Science, Baylor University, Waco, TX 76798, United States of America
| | - Karla Johanning
- KJ Scientific, LLC, Georgetown, TX 78626, United States of America
| | - Cole W Matson
- Department of Environmental Science, Baylor University, Waco, TX 76798, United States of America; Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX 76798, United States of America
| | - Ramon Lavado
- Department of Environmental Science, Baylor University, Waco, TX 76798, United States of America.
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Weeks J, Li AP, Doshi U, Johanning K, Guiney PD. In vitro evaluation of the metabolic stability of nine fragrance chemicals in trout and human hepatocytes. J Appl Toxicol 2020; 40:1421-1434. [PMID: 32488907 DOI: 10.1002/jat.3995] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 04/01/2020] [Accepted: 04/15/2020] [Indexed: 12/11/2022]
Abstract
In vitro metabolic stability of nine fragrance chemicals: p-tolyl acetate, cashmeran, ethylene brassylate, celestolide, galaxolide, traseolide, ambretone, tonalide and pentadecanolide, was evaluated in trout and human hepatocytes. The compounds were incubated with trout hepatocytes at 12°C and human hepatocytes at 37°C. Quantification of compound disappearance with time was performed using gas chromatography/mass spectrometry. in vivo hepatic intrinsic clearance values were calculated from the in vitro data. Significant metabolism was observed with trout hepatocytes for five of the nine fragrance chemicals, while all nine were metabolized significantly with human hepatocytes. Previously published models were used to examine expected bioaccumulation and persistence in whole organisms. Calculated half-lives due to metabolism of the nine chemicals are significantly shorter for humans than trout: <1 hour and <1 day, respectively. For all chemicals with demonstrated hepatic metabolism, the models indicate a lack of accumulation. For those where metabolism was demonstrated in trout, calculated bioconcentration factors would not be classified as bioaccumulative under prevailing regulatory systems.
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Affiliation(s)
- John Weeks
- S.C. Johnson and Son, Inc., Racine, Wisconsin, US
| | - Albert P Li
- In Vitro ADMET Laboratories LLC, Columbia, Maryland, US
| | - Utkarsh Doshi
- In Vitro ADMET Laboratories LLC, Columbia, Maryland, US.,Altria Client Services LLC, Richmond, Virginia, US
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5
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Weeks J, Guiney P, Johanning K. In vitro and in vivo metabolic stability of various fragrance materials and insect repellent in rainbow trout (
Oncorhynchus mykiss
). J Appl Toxicol 2020; 40:763-779. [DOI: 10.1002/jat.3942] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 12/19/2019] [Accepted: 12/21/2019] [Indexed: 11/10/2022]
Affiliation(s)
- John Weeks
- SC Johnson and Son, Inc. Racine Wisconsin
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6
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Nichols J, Fay K, Bernhard MJ, Bischof I, Davis J, Halder M, Hu J, Johanning K, Laue H, Nabb D, Schlechtriem C, Segner H, Swintek J, Weeks J, Embry M. Reliability of In Vitro Methods Used to Measure Intrinsic Clearance of Hydrophobic Organic Chemicals by Rainbow Trout: Results of an International Ring Trial. Toxicol Sci 2018; 164:563-575. [PMID: 29767801 PMCID: PMC6061802 DOI: 10.1093/toxsci/kfy113] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In vitro assays are widely employed to obtain intrinsic clearance estimates used in toxicokinetic modeling efforts. However, the reliability of these methods is seldom reported. Here we describe the results of an international ring trial designed to evaluate two in vitro assays used to measure intrinsic clearance in rainbow trout. An important application of these assays is to predict the effect of biotransformation on chemical bioaccumulation. Six laboratories performed substrate depletion experiments with cyclohexyl salicylate, fenthion, 4-n-nonylphenol, deltamethrin, methoxychlor, and pyrene using cryopreserved hepatocytes and liver S9 fractions from trout. Variability within and among laboratories was characterized as the percent coefficient of variation (CV) in measured in vitro intrinsic clearance rates (CLIN VITRO, INT; ml/h/mg protein or 106 cells) for each chemical and test system. Mean intralaboratory CVs for each test chemical averaged 18.9% for hepatocytes and 14.1% for S9 fractions, whereas interlaboratory CVs (all chemicals and all tests) averaged 30.1% for hepatocytes and 22.4% for S9 fractions. When CLIN VITRO, INT values were extrapolated to in vivo intrinsic clearance estimates (CLIN VIVO, INT; l/d/kg fish), both assays yielded similar levels of activity (<4-fold difference for all chemicals). Hepatic clearance rates (CLH; l/d/kg fish) calculated using data from both assays exhibited even better agreement. These findings show that both assays are highly reliable and suggest that either may be used to inform chemical bioaccumulation assessments for fish. This study highlights several issues related to the demonstration of assay reliability and may provide a template for evaluating other in vitro biotransformation assays.
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Affiliation(s)
- John Nichols
- ORD, NHEERL, Mid-Continent Ecology Division, U.S. Environmental Protection Agency, Duluth, Minnesota
| | - Kellie Fay
- Biology Department, University of Minnesota, Duluth, Minnesota, 55804
- CSRA Inc, Duluth, Minnesota
| | | | - Ina Bischof
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany, 57392
| | - John Davis
- The Dow Chemical Company, Midland, Michigan, 48674
| | - Marlies Halder
- European Commission, Joint Research Centre, Ispra, Italy, I-21027
| | - Jing Hu
- The Dow Chemical Company, Midland, Michigan, 48674
| | | | - Heike Laue
- Givaudan Schweiz AG, Dübendorf, Switzerland, 8600
| | - Diane Nabb
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, Delaware
| | - Christian Schlechtriem
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany, 57392
| | - Helmut Segner
- Centre for Fish and Wildlife Health, University of Bern, Bern, Switzerland, 3001
| | - Joe Swintek
- Badger Technical Services, Duluth, Minnesota, 55804
| | - John Weeks
- Weeks Entox, Knoxville, Tennessee, 37931
| | - Michelle Embry
- Health and Environmental Sciences Institute, Washington, District of Columbia 20005
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7
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Fay KA, Nabb DL, Mingoia RT, Bischof I, Nichols JW, Segner H, Johanning K, Han X. Determination of Metabolic Stability Using Cryopreserved Hepatocytes from Rainbow Trout (
Oncorhynchus mykiss
). ACTA ACUST UNITED AC 2015; 65:4.42.1-4.42.29. [DOI: 10.1002/0471140856.tx0442s65] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Kellie A. Fay
- ORD/NHEERL/Mid‐Continent Ecology Division, U.S. EPA Duluth Minnesota
| | - Diane L. Nabb
- DuPont Haskell Global Centers for Health and Environmental Sciences Newark Delaware
| | - Robert T. Mingoia
- DuPont Haskell Global Centers for Health and Environmental Sciences Newark Delaware
| | - Ina Bischof
- Centre for Fish and Wildlife Health, University of Bern Bern Switzerland
- Fraunhofer Institute for Molecular Biology and Applied Ecology Schmallenberg Germany
| | - John W. Nichols
- ORD/NHEERL/Mid‐Continent Ecology Division, U.S. EPA Duluth Minnesota
| | - Helmut Segner
- Centre for Fish and Wildlife Health, University of Bern Bern Switzerland
| | - Karla Johanning
- KJ Scientific LCC, Texas Life Sciences Collaboration Center Georgetown Texas
| | - Xing Han
- DuPont Haskell Global Centers for Health and Environmental Sciences Newark Delaware
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8
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Johanning K. Point-of-care-Diagnostik vs. Standardlabor beim Polytrauma. Unfallchirurg 2014; 117:118-22. [DOI: 10.1007/s00113-013-2489-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Johanning K, Hancock G, Escher B, Adekola A, Bernhard MJ, Cowan-Ellsberry C, Domoradzki J, Dyer S, Eickhoff C, Embry M, Erhardt S, Fitzsimmons P, Halder M, Hill J, Holden D, Johnson R, Rutishauser S, Segner H, Schultz I, Nichols J. Assessment of metabolic stability using the rainbow trout (Oncorhynchus mykiss) liver S9 fraction. ACTA ACUST UNITED AC 2013; Chapter 14:Unit 14.10.1-28. [PMID: 22896006 DOI: 10.1002/0471140856.tx1410s53] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Standard protocols are given for assessing metabolic stability in rainbow trout using the liver S9 fraction. These protocols describe the isolation of S9 fractions from trout livers, evaluation of metabolic stability using a substrate depletion approach, and expression of the result as in vivo intrinsic clearance. Additional guidance is provided on the care and handling of test animals, design and interpretation of preliminary studies, and development of analytical methods. Although initially developed to predict metabolism impacts on chemical accumulation by fish, these procedures can be used to support a broad range of scientific and risk assessment activities including evaluation of emerging chemical contaminants and improved interpretation of toxicity testing results. These protocols have been designed for rainbow trout and can be adapted to other species as long as species-specific considerations are modified accordingly (e.g., fish maintenance and incubation mixture temperature). Rainbow trout is a cold-water species. Protocols for other species (e.g., carp, a warm-water species) can be developed based on these procedures as long as the specific considerations are taken into account.
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Affiliation(s)
- Karla Johanning
- KJohanning Consultancy, Pura Vida Connections LLC, Austin, Texas, USA
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Escher BI, Cowan-Ellsberry CE, Dyer S, Embry MR, Erhardt S, Halder M, Kwon JH, Johanning K, Oosterwijk MTT, Rutishauser S, Segner H, Nichols J. Protein and lipid binding parameters in rainbow trout (Oncorhynchus mykiss) blood and liver fractions to extrapolate from an in vitro metabolic degradation assay to in vivo bioaccumulation potential of hydrophobic organic chemicals. Chem Res Toxicol 2011; 24:1134-43. [PMID: 21604782 DOI: 10.1021/tx200114y] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Binding of hydrophobic chemicals to colloids such as proteins or lipids is difficult to measure using classical microdialysis methods due to low aqueous concentrations, adsorption to dialysis membranes and test vessels, and slow kinetics of equilibration. Here, we employed a three-phase partitioning system where silicone (polydimethylsiloxane, PDMS) serves as a third phase to determine partitioning between water and colloids and acts at the same time as a dosing device for hydrophobic chemicals. The applicability of this method was demonstrated with bovine serum albumin (BSA). Measured binding constants (K(BSAw)) for chlorpyrifos, methoxychlor, nonylphenol, and pyrene were in good agreement with an established quantitative structure-activity relationship (QSAR). A fifth compound, fluoxypyr-methyl-heptyl ester, was excluded from the analysis because of apparent abiotic degradation. The PDMS depletion method was then used to determine partition coefficients for test chemicals in rainbow trout (Oncorhynchus mykiss) liver S9 fractions (K(S9w)) and blood plasma (K(bloodw)). Measured K(S9w) and K(bloodw) values were consistent with predictions obtained using a mass-balance model that employs the octanol-water partition coefficient (K(ow)) as a surrogate for lipid partitioning and K(BSAw) to represent protein binding. For each compound, K(bloodw) was substantially greater than K(S9w), primarily because blood contains more lipid than liver S9 fractions (1.84% of wet weight vs 0.051%). Measured liver S9 and blood plasma binding parameters were subsequently implemented in an in vitro to in vivo extrapolation model to link the in vitro liver S9 metabolic degradation assay to in vivo metabolism in fish. Apparent volumes of distribution (V(d)) calculated from the experimental data were similar to literature estimates. However, the calculated binding ratios (f(u)) used to relate in vitro metabolic clearance to clearance by the intact liver were 10 to 100 times lower than values used in previous modeling efforts. Bioconcentration factors (BCF) predicted using the experimental binding data were substantially higher than the predicted values obtained in earlier studies and correlated poorly with measured BCF values in fish. One possible explanation for this finding is that chemicals bound to proteins can desorb rapidly and thus contribute to metabolic turnover of the chemicals. This hypothesis remains to be investigated in future studies, ideally with chemicals of higher hydrophobicity.
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Affiliation(s)
- Beate I Escher
- The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Road, Brisbane, Qld 4108, Australia.
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12
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Osthaus WA, Witt L, Johanning K, Boethig D, Winterhalter M, Huber D, Heimbucher C, Suempelmann R. Equal effects of gelatin and hydroxyethyl starch (6% HES 130/0.42) on modified thrombelastography in children. Acta Anaesthesiol Scand 2009; 53:305-10. [PMID: 19173690 DOI: 10.1111/j.1399-6576.2008.01863.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Artificial colloids are frequently used to prevent or treat circulatory failure due to hypovolaemia. Whereas gelatin has been shown not to affect coagulation besides its haemodilutional effect, hydroxyethyl starches (HES) have additional negative effects on haemostasis. The third-generation HES solutions have been developed to minimise these effects. We therefore conducted a prospective, randomised study, to verify the hypothesis that a 6% HES 130/0.42/6 : 1 and a 4% gelatin infusion influences modified thrombelastography (TEM) parameters in children in the same manner and to the same extent. METHODS A total of 50 paediatric patients aged 0-12 years scheduled for surgery were assigned to receive either 10 ml/kg HES 130/0.42 or gelatin. Blood gas analysis, haemodynamic parameters and TEM measurements were performed before and after colloid administration. RESULTS Patient characteristics, indications/surgical procedures and the main results obtained from blood gas analysis were comparable between the two groups. After administration of either gelatin or HES, all TEM parameters, except for clotting time, indicated impaired coagulation whereas the mean values of all TEM parameters remained within the normal ranges. Comparing the gelatin and HES 130/0.42/6 : 1 groups, none of the measured TEM parameters was found to show between-group differences at baseline or after colloid infusion. CONCLUSION In conclusion, we could demonstrate that the investigational product, HES 130/0.42/6 : 1 solution, administered at a dosage of 10 ml/kg to children, had comparable effects on coagulation monitored with TEM as a gelatin solution. Perioperative administration of HES 130/0.42/6 : 1 does not alter coagulation to an extent above and beyond the effect of haemodilution.
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Affiliation(s)
- W A Osthaus
- Klinik fuer Anaesthesiologie und Intensivmedizin, Medizinische Hochschuele, Hannover, D-30625 Hannover, Germany.
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13
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Peinado JR, Li H, Johanning K, Lindberg I. Cleavage of recombinant proenkephalin and blockade mutants by prohormone convertases 1 and 2: an in vitro specificity study. J Neurochem 2004; 87:868-78. [PMID: 14622118 DOI: 10.1046/j.1471-4159.2003.02043.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Proenkephalin (PE) derived-peptides are thought to be generated predominantly through endoproteolytic cleavage by prohormone convertases 1 and 2 (PC1 and PC2). In order to compare cleavage site preferences of these convertases, we studied the processing of recombinant wild-type rat PE and of two mutant PEs by recombinant purified mouse PC1 and PC2. Western blot analyses of timed digestions showed that both mouse PC1 and PC2 were able to produce a variety of large and intermediate sized-peptides from wild-type PE as well as from the precursors mutated at initial blockade sites. PC2 exhibited a broader specificity against PE than PC1, generating a much greater number of peptide products. Mass spectrometric identification of cleavage products showed that PC2 appeared to be the principal enzyme involved in the generation of smaller active opioids. Both enzymes were able to cleave various KR- and KK-containing sites, but PC2 was also able to cleave efficiently at an RR-V site and a KK-M site not cleaved by PC1, suggesting the exclusion of large aliphatic residues at the P1' position in PC1 cleavage. Alternative cleavage sites were readily chosen by convertases in blockade mutants, confirming in vivo results that cleavages do not follow an obligatory order. Furthermore, glycosylated PE was less efficiently processed by PC2, indicating that glycosylation may serve as a mechanism to hinder processing.
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Affiliation(s)
- Juan R Peinado
- Department of Biochemistry and Molecular Biology, Lousiana State University Medical Center, School of Medicine, New Orleans, Louisiana 70112, USA
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14
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Abstract
Alu elements sharing sequence characteristics of the "old" subfamilies are thought to currently be retrotranspositionally inactive. We analyzed one of these old subfamilies of Alu elements, Sx, for sequence conservation relative to the consensus and the length of the "A-tail" as parameters to define the presence of potential Alu Sx source genes in the human genome. Sequence identity to the left half or the right half of the Alu Sx consensus sequence was evaluated for 4424 complete elements obtained from the human genome draft sequence. A small subset of Alu Sx left halves were found to be more conserved than any of the Alu Sx right halves. Selection for promoter function in active elements may explain the slightly higher conservation of the left half. In order to determine whether this sequence identity was the result of recent activity, or simply sequence conservation for older elements, PCR amplification of some of the loci containing Sx elements with conserved left/right halves from different primate genomes was carried out. Several of these Sx Alus were found to have amplified at a later evolutionary period (<35 mya) than expected based on previous studies of Sx elements. Analysis of "A-tail" length, a feature correlated with current retroposition activity, varied between Alu Sx element loci in different primates, where the length increased in specific Alu elements in the human genome. The presence of few conserved Alu Sx elements and the dynamic expansion/contraction of the A-tail suggests that some of these older subfamilies may still be active at very low levels or in a few individuals.
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Affiliation(s)
- Karla Johanning
- Tulane Cancer Center SL-66, Department of Environmental Health Sciences, Tulane University Medical Center, 1430 Tulane Avenue, New Orleans, LA 70112, USA
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15
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Johanning K, Juliano MA, Juliano L, Lazure C, Lamango NS, Steiner DF, Lindberg I. Specificity of prohormone convertase 2 on proenkephalin and proenkephalin-related substrates. J Biol Chem 1998; 273:22672-80. [PMID: 9712897 DOI: 10.1074/jbc.273.35.22672] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the central and peripheral nervous systems, the neuropeptide precursor proenkephalin must be endoproteolytically cleaved by enzymes known as prohormone convertases 1 and 2 (PC1 and PC2) to generate opioid-active enkephalins. In this study, we have investigated the specificity of recombinant mouse PC2 for proenkephalin-related internally quenched (IQ) peptides, for methylcoumarin amide-based fluorogenic peptides, and for recombinant rat proenkephalin. IQ peptides exhibited specificity constants (kcat/Km) between 9.4 x 10(4) M-1 s-1 (Abz-Val-Pro-Arg-Met-Glu-Lys-Arg-Tyr-Gly-Gly-Phe-Met-Gln-EDDnp+ ++; where Abz is ortho-aminobenzoic acid and EDDnp is N-(2, 4-dinitrophenyl)ethylenediamine)) and 0.24 x 10(4) M-1 s-1 (Abz-Tyr-Gly-Gly-Phe-Met-Arg-Arg-Val-Gly-Arg-Pro-Glu-EDDnp), with the peptide B to Met-enk-Arg-Phe cleavage preferred (Met-enk is met-enkephalin). Fluorogenic substrates with P1, P2, and P4 basic amino acids were hydrolyzed with specificity constants ranging between 2.0 x 10(3) M-1 s-1 (Ac-Orn-Ser-Lys-Arg-MCA; where MCA is methylcoumarin amide) and 1.8 x 10(4) M-1 s-1 (<Glu-Arg-Thr-Lys-Arg-MCA; where <Glu is pyroglutamic acid). Substrates containing only a single basic residue were not appreciably hydrolyzed, and substrates lacking a P4 Arg exhibited kcat of less than 0.05 s-1. Substitution of ornithine for Lys at the P4 position did not significantly affect the kcat but increased the Km 2-fold. Data from both sets of fluorogenic substrates supported the contribution of a P4 Arg to PC2 preference. Analysis of proenkephalin reaction products using immunoblotting and gel permeation chromatography demonstrated that PC2 can directly cleave proenkephalin and that the generation of small opioid peptides from intermediates is mediated almost entirely by PC2 rather than by PC1. These results are in accord with the analysis of PC2 knock-out brains, in which the amounts of three mature enkephalins were depleted by more than three-quarters.
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Affiliation(s)
- K Johanning
- Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, School of Medicine, New Orleans, Louisiana 70112, USA
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16
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Abstract
Prohormones are known to be processed at various cleavage sites in a defined temporal order, suggesting the possibility of sequential unfolding of processing sites. In order to investigate whether sequential processing at predefined sites is in fact required for proper processing, site-directed mutagenesis was performed to block known initial cleavage sites within proenkephalin. Pulse-chase/immunoprecipitation experiments were employed to analyze the fate of mutant and native proenkephalins in stably transfected AtT-20 cells. While processing did not occur at blockaded sites, surprisingly, overall processing of mutant proenkephalins proceeded efficiently, and alternative sites were chosen. When compared with native proenkephalin, processing of mutant proenkephalins occurred more slowly at early stages and more quickly at later stages. Experiments employing endoglycosidase H indicated that the early slow processing of mutant proenkephalins may be due to delays in intracellular transport. Metabolic labeling studies showed that more efficient production of bioactive opioids occurred in all processing site blockade mutants examined; these results were confirmed using several different radioimmunoassays of stored peptide products. We conclude that efficient processing of prohormone precursors does not require a specific temporal order of processing events. The fact that mutant proenkephalins were more fully processed than native proenkephalin may provide a route for more efficient production of opioid peptides in applications for chronic pain treatment.
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Affiliation(s)
- K Johanning
- Department of Biochemistry and Molecular Biology, Louisiana State University School of Medicine, New Orleans, Louisiana 70112, USA.
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Abstract
The contribution of the prohormone-processing enzyme PC2 to the proteolytic maturation of proenkephalin was examined in three sets of studies. In the first, the processing of this precursor was compared in PC2-rich (Rin5f) and PC2-lacking (AtT-20) cell lines expressing proenkephalin by virtue of stable transfection. These studies showed that the time frame for processing of this precursor is cell line specific, with AtT-20 cells processing proenkephalin to peptide B much more rapidly than Rin cells. However, the latter cell line processed proenkephalin much more extensively, i.e., produced a greater proportion of the penta- to octapeptide enkephalins. The involvement of PC2 in these later processing events was analyzed by examining the processing of proenkephalin in PC2-overexpressing AtT-20 cell lines. These experiments yielded a processing profile similar to that observed for Rin cells, although the time frame of initial processing was similar to that found in AtT-20 cells. To confirm the physiological involvement of proenkephalin in the production of the small opioid peptides, we generated a Rin cell line in which the production of PC2 was impaired due to stable expression of antisense mRNA to this enzyme. These experiments provided conclusive evidence that the generation of Met-enkephalin-Arg-Phe and Met-enkephalin-Arg-Gly-Leu, but not the larger enkephalin-containing peptides, is mediated by PC2. Taken together, our data support the idea that PC2 is physiologically capable of mediating only the later processing steps of neuropeptide precursors. PC2 thus appears to be the primary enzyme responsible for the generation of bioactive opioid peptide species from proenkephalin.
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Affiliation(s)
- K Johanning
- Department of Biochemistry and Molecular Biology, Louisiana State University School of Medicine, New Orleans 70112, USA
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