2009 IEEE International Geoscience and Remote Sensing Symposium, 2009
In radar imaging, the assumption is made that scatterers are white in the emitted frequency band ... more In radar imaging, the assumption is made that scatterers are white in the emitted frequency band and isotropic for all direction of observation. Nevertheless, new capacities in radar imaging, using a wideband and a large angular excursion, make these hypotheses not valid. Time-frequency analysis highlight this point of view and show some scatterers are anisotropic and/or dispersive. This information source can be completed by radar polarimetry. This paper suggests a supervised classification of scatterers using neural networks based on polarimetric time-frequency signatures. This method is applied here on anechoic chamber data, however can be generalized to SAR or circular SAR imaging.
The cDNA of the microsomal Juvenile Hormone Epoxide Hydrolase (JHEH) from Manduca sexta was expre... more The cDNA of the microsomal Juvenile Hormone Epoxide Hydrolase (JHEH) from Manduca sexta was expressed in vitro in the baculovirus system. In insect cell culture, the recombinant enzyme (Ms-JHEH) was produced at a high level (100 fold over background EH catalytic activity). As expected, Ms-JHEH was localized in the microsomal fraction with a molecular mass of approximately 50 kDa. Ms-JHEH showed a substrate and inhibitor spectrum similar to the wild type JHEH isolated from eggs of M. sexta. Its enzymatic activity was the highest for Juvenile Hormone III. Ms-JHEH hydrolyzed several trans-epoxides faster than cis-epoxides. A putative hydroxyl-acyl enzyme intermediate was isolated suggesting a catalytic mechanism of Ms-JHEH similar to the mammalian EHs.
The human soluble epoxide hydrolase (sEH; EC 3.3.3.2) is the product of the EXPH2 gene. The sEH c... more The human soluble epoxide hydrolase (sEH; EC 3.3.3.2) is the product of the EXPH2 gene. The sEH catalyzes the addition of a water molecule to an epoxide, resulting in the corresponding diol. Early work suggested a role of sEH in detoxifying a wide array of xenobiotic epoxides; however, recent findings clearly implicate the sEH in the regulation of blood pressure, pain, and inflammation through the hydrolysis of endogenous epoxy fatty acids such as epoxyeicosatrienoic acids (EETs). Both expression and activity of sEH are influenced by a wide array of xenobiotics, underlying how environmental contaminants could influence human health through sEH. This unit describes radiometric, fluorimetric, and mass spectrometric assays for measuring the activity of sEH and its inhibition.
Dynamic analysis of the uptake and metabolism of polycyclic aromatic hydrocarbons (PAHs) and thei... more Dynamic analysis of the uptake and metabolism of polycyclic aromatic hydrocarbons (PAHs) and their metabolites within live cells in real time has the potential to provide novel insights into genotoxic and non-genotoxic mechanisms of cellular injury caused by PAHs. The present work, combining the use of metabolite spectra generated from metabolite standards using multiphoton spectral analysis and an "advanced unmixing process", identifies and quantifies the uptake, partitioning, and metabolite formation of one of the most important PAHs (benzo[a]pyrene, BaP) in viable cultured rat liver cells over a period of 24 h. The application of the advanced unmixing process resulted in the simultaneous identification of 8 metabolites in live cells at any single time. The accuracy of this unmixing process was verified using specific microsomal epoxide hydrolase inhibitors, glucuronidation and sulfation inhibitors as well as several mixtures of metabolite standards. Our findings prove that the two-photon microscopy imaging surpasses the conventional fluorescence imaging techniques and the unmixing process is a mathematical technique that seems applicable to the analysis of BaP metabolites in living cells especially for analysis of changes of the ultimate carcinogen benzo[a]pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide. Therefore, the combination of the two-photon acquisition with the unmixing process should provide important insights into the cellular and molecular mechanisms by which BaP and other PAHs alter cellular homeostasis.
2009 IEEE International Geoscience and Remote Sensing Symposium, 2009
In radar imaging, the assumption is made that scatterers are white in the emitted frequency band ... more In radar imaging, the assumption is made that scatterers are white in the emitted frequency band and isotropic for all direction of observation. Nevertheless, new capacities in radar imaging, using a wideband and a large angular excursion, make these hypotheses not valid. Time-frequency analysis highlight this point of view and show some scatterers are anisotropic and/or dispersive. This information source can be completed by radar polarimetry. This paper suggests a supervised classification of scatterers using neural networks based on polarimetric time-frequency signatures. This method is applied here on anechoic chamber data, however can be generalized to SAR or circular SAR imaging.
The cDNA of the microsomal Juvenile Hormone Epoxide Hydrolase (JHEH) from Manduca sexta was expre... more The cDNA of the microsomal Juvenile Hormone Epoxide Hydrolase (JHEH) from Manduca sexta was expressed in vitro in the baculovirus system. In insect cell culture, the recombinant enzyme (Ms-JHEH) was produced at a high level (100 fold over background EH catalytic activity). As expected, Ms-JHEH was localized in the microsomal fraction with a molecular mass of approximately 50 kDa. Ms-JHEH showed a substrate and inhibitor spectrum similar to the wild type JHEH isolated from eggs of M. sexta. Its enzymatic activity was the highest for Juvenile Hormone III. Ms-JHEH hydrolyzed several trans-epoxides faster than cis-epoxides. A putative hydroxyl-acyl enzyme intermediate was isolated suggesting a catalytic mechanism of Ms-JHEH similar to the mammalian EHs.
The human soluble epoxide hydrolase (sEH; EC 3.3.3.2) is the product of the EXPH2 gene. The sEH c... more The human soluble epoxide hydrolase (sEH; EC 3.3.3.2) is the product of the EXPH2 gene. The sEH catalyzes the addition of a water molecule to an epoxide, resulting in the corresponding diol. Early work suggested a role of sEH in detoxifying a wide array of xenobiotic epoxides; however, recent findings clearly implicate the sEH in the regulation of blood pressure, pain, and inflammation through the hydrolysis of endogenous epoxy fatty acids such as epoxyeicosatrienoic acids (EETs). Both expression and activity of sEH are influenced by a wide array of xenobiotics, underlying how environmental contaminants could influence human health through sEH. This unit describes radiometric, fluorimetric, and mass spectrometric assays for measuring the activity of sEH and its inhibition.
Dynamic analysis of the uptake and metabolism of polycyclic aromatic hydrocarbons (PAHs) and thei... more Dynamic analysis of the uptake and metabolism of polycyclic aromatic hydrocarbons (PAHs) and their metabolites within live cells in real time has the potential to provide novel insights into genotoxic and non-genotoxic mechanisms of cellular injury caused by PAHs. The present work, combining the use of metabolite spectra generated from metabolite standards using multiphoton spectral analysis and an "advanced unmixing process", identifies and quantifies the uptake, partitioning, and metabolite formation of one of the most important PAHs (benzo[a]pyrene, BaP) in viable cultured rat liver cells over a period of 24 h. The application of the advanced unmixing process resulted in the simultaneous identification of 8 metabolites in live cells at any single time. The accuracy of this unmixing process was verified using specific microsomal epoxide hydrolase inhibitors, glucuronidation and sulfation inhibitors as well as several mixtures of metabolite standards. Our findings prove that the two-photon microscopy imaging surpasses the conventional fluorescence imaging techniques and the unmixing process is a mathematical technique that seems applicable to the analysis of BaP metabolites in living cells especially for analysis of changes of the ultimate carcinogen benzo[a]pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide. Therefore, the combination of the two-photon acquisition with the unmixing process should provide important insights into the cellular and molecular mechanisms by which BaP and other PAHs alter cellular homeostasis.
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