Jorge Estévez

Jorge Estévez
Universidad Miguel Hernández de Elche | UMH · Institute of Bioengineering

PhD

About

53
Publications
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490
Citations

Publications

Publications (53)
Article
Full-text available
Quantum dots are nanoparticles with very promising biomedical applications. However, before these applications can be authorized, a complete toxicological assessment of quantum dots toxicity is needed. This work studied the effects of cadmium-selenium quantum dots on the transcriptome of T98G human glioblastoma cells. It was found that 72-h exposur...
Article
Full-text available
Phenyl valerate (PV) is a neutral substrate for measuring the PVase activity of neuropathy target esterase (NTE), a key molecular event of organophosphorus-induced delayed neuropathy. This substrate has been used to discriminate and identify other proteins with esterase activity and potential targets of organophosphorus (OP) binding. A protein with...
Article
Full-text available
Titanium dioxide and zinc oxide are two of the most widely used nanomaterials. We assessed the effects of noncytotoxic doses of both nanomaterials on T98G human glioblastoma cells by omic approaches. Surprisingly, no effects on the transcriptome of T98G cells was detected after exposure to 5 µg/mL of zinc oxide nanoparticles during 72 h. Conversely...
Article
Nanotechnology has been well developed in recent decades because it provides social progress and welfare. Consequently, exposure of population is increasing and further increases in the near future are forecasted. Therefore, assessing the safety of applications involving nanoparticles is strongly advisable. We assessed the effects of silver nanopar...
Chapter
DFP (diisopropylfluorophosphate) [(C3H7)2-P(O)-F] is a dialkyl fluorophosphate synthesized in the 1930s by procedures patented looking either for insecticides, mold control, warfare agents, or fluorine compounds for dental protection. It has been extensively used in research as a model compound of an acetylcholinesterase inhibitor and in other toxi...
Article
Full-text available
The Risk Assessment Committee of the European Chemical Agency released a scientific opinion alerting that the risk associated with dermal occupational exposure to bisphenol A (BPA) via thermal paper might not be adequately controlled because the estimated exposure was around twice the Derived No Effect Level (DNEL) and the European Commission will...
Article
Full-text available
Phenyl valerate (PV) is a substrate for measuring the PVase activity of neuropathy target esterase (NTE), a key molecular event of organophosphorus-induced delayed neuropathy. A protein with PVase activity in chicken (model for delayed neurotoxicity) was identified as butyrylcholinesterase (BChE). Purified human butyrylcholinesterase (hBChE) showed...
Article
The molecular targets of best known neurotoxic effects associated to acute exposure to organophosphorus compounds (OPs) are serine esterases located in the nervous system, although there are other less known neurotoxic adverse effects associated with chronic exposure to OPs whose toxicity targets are still not identified. In this work we studied se...
Article
Some effects of organophosphorus compounds (OPs) esters cannot be explained by action on currently recognized targets acetylcholinesterase or neuropathy target esterase (NTE). In previous studies, in membrane chicken brain fractions, four components (EPα, EPβ, EPγ and EPδ) of phenyl valerate esterase activity (PVase) had been kinetically discrimina...
Article
Full-text available
Inhibition and aging of neuropathy target esterase (NTE) by exposure to neuropathic organophosphorus compounds (OPs) can result in OP-induced delayed neuropathy (OPIDN). In the present study we aimed to build a model of OPIDN in adult zebrafish. First, inhibition and aging of zebrafish NTE activity were characterized in the brain by using the proto...
Article
Full-text available
Phenyl valerate is used for detecting and measuring neuropathy target esterase (NTE) and has been used for discriminating esterases as potential target in hen model of organophosphorus delayed neuropathy. In previous studies we observed that phenyl valerate esterase (PVase) activity of an enzymatic fraction in chicken brain might be due to a butyry...
Article
Full-text available
Multiple epidemiological and experimental studies have demonstrated that exposure to organophosphorus compounds (OPs) is associated with a variety of neurological disorders. Some of these exposure symptoms cannot be precisely correlated with known molecular targets and mechanisms of toxicity. Most of the known molecular targets of OPs fall in the p...
Poster
Organophosphorus compounds (OPs) induce neurotoxic disorders through interactions with well-known target esterases, such as acetylcholinesterase and neuropathy target esterase (NTE).However, OPs interact with other esterases of unknown biological function. Our aim is the identification of new targets of OP toxicity. In membrane chicken brain fracti...
Article
Some effects of organophosphorus compounds (OPs) esters cannot be explained through actions on currently recognized targets acetylcholinesterase or neuropathy target esterase (NTE). In soluble chicken brain fraction, three components (Eα, Eβ and Eγ) of pheny lvalerate esterase activity (PVase) were kinetically discriminated and their relationship w...
Article
Neuropathy Target Esterase (NTE) is a membrane protein codified by gene PNPLA6. NTE was initially discovered as a target of the so-called organophosphorus-induced delayed polyneuropathy triggered by the inhibition of the NTE-associated esterase center by neuropathic organophosphorus compounds (OPs). The physiological role of NTE might be related to...
Article
Organophosphorus compounds (OPs) are a large and diverse class of chemicals mainly used as pesticides and chemical weapons. People may be exposed to OPs in several occasions, which can produce several distinct neurotoxic effects depending on the dose, frequency of exposure, type of OP, and the host factors that influence susceptibility and sensitiv...
Article
Full-text available
Organophosphorus compounds (OPs) are a large and diverse class of chemicals that have been synthesized, since the XIX century for several purposes like chemical weapons, flame-retardants, ectoparasiticides and investigational new drugs, but mainly as agrochemicals in agriculture and indoor. Although the amount of OP pesticides being used is declini...
Article
Chlorpyrifos (CPS) is an organophosphorus compound (OP) capable of causing well-known cholinergic and delayed syndromes through the inhibition of acetylcholinesterase and Neuropathy Target Esterase (NTE), respectively. CPS is also able to induce neurodevelopmental toxicity in animals. NTE is codified by the Pnpla6 gene and plays a central role in d...
Article
OPs are a large diverse class of chemicals used for several purposes (pesticides, warfare agents, flame retardants, etc.). They can cause several neurotoxic disorders: acute cholinergic toxicity, organophosphorus-induced delayed neuropathy, long-term neurobehavioral and neuropsychological symptoms, and potentiation of neuropathy. Some of these synd...
Chapter
DFP (diisopropylfluorophosphate; (C3H7)2-P(O)-F) is a dialkylfluorophosphate synthesized in the 1930s by procedures patented for insecticides, mold control, warfare agents, and fluorine compounds for dental protection. However, DFP has never been produced for chemical warfare and is not used as an insecticide. It has been extensively used in resear...
Article
Full-text available
The hydroxyl oxygen of the catalytic triad serine in the active center of serine hydrolase acetylcholinesterase (AChE) attacks organophosphorus compounds (OPs) at the phosphorus atom to displace the primary leaving group and to form a covalent bond. Inhibited AChE can be reactivated by cleavage of the Ser-phosphorus bond either spontaneously or thr...
Chapter
Chloroform is a volatile, heavy, colorless liquid substance. It is used as an intermediate in the production of dyes, pesticides, and other substances, as a production and extraction solvent, in the water chlorination, and in the pulp and paper bleaching. The organs that most actively metabolize chloroform (liver, kidney, etc.) are also the chief t...
Article
Full-text available
Many cholinesterase assays are performed to study the inhibition of cholinesterase (ChE) activity. Frequently a large number of samples are processed and Ellman's method [1] is the most commonly used [2,3]. Activity is estimated from the increment in absorbance between two reaction times when the reaction is not stopped. Bellino et al. [4] describe...
Article
Biomarkers yield information as to whether an organism has been exposed to a xenobiotic (biomarkers of exposure), about the response of the organism exposed to the xenobiotic (biomarkers of effect), or about the susceptibility of the organism to xenobiotics. Biomarkers of exposure can be used to biomonitor xenobiotic exposure, even after the organi...
Article
Organophosphorus compounds (OPs) induce neurotoxic disorders through interactions with well-known target esterases, such as acetylcholinesterase and neuropathy target esterase (NTE). However, OPs interact with other esterases of unknown biological function. In soluble chicken brain fractions, three components of enzymatic phenylvalerate esterase ac...
Article
Low level exposure to organophosphorus esters (OPs) may cause long-term neurological effects and affect specific cognition domains in experimental animals and humans. Action on known targets cannot explain most of these effects by. Soluble carboxylesterases (EC 3.1.1.1) of chicken brain have been kinetically discriminated using paraoxon, mipafox an...
Article
Phenylmethylsulfonyl fluoride (PMSF) is a protease and esterase inhibitor that causes protection, or potentiation/“promotion,” of organophosphorus delayed neuropathy (OPIDN), depending on whether it is dosed before or after an inducer of delayed neuropathy, such as mipafox. The molecular target of the potentiation/promotion of OPIDN has not yet bee...
Article
Organophosphorus compounds (OPs) cause neurotoxic disorders through interactions with well-known target esterases, such as acetylcholinesterase and neuropathy target esterase (NTE). However,the OPs can potentially interact with other esterases of unknown significance. Therefore, identifying, characterizing and elucidating the nature and functional...
Article
Phenylmethylsulfonyl fluoride (PMSF) is a protease and esterase inhibitor that causes protection or potentiation/promotion of organophosphorus delayed neuropathy (OPIDN) depending on whether it is dosed before or after an inducer of delayed neuropathy. The molecular target of promotion has not yet been identified. Kinetic data of esterase inhibitio...
Article
Some effects of organophosphorus compounds (OPs) esters cannot be explained by action on currently recognized targets. In this work, we evaluate and characterize the interaction (inhibition, reactivation and "ongoing inhibition") of two model compounds: paraoxon (non-neuropathy-inducer) and mipafox (neuropathy-inducer), with esterases of chicken br...
Article
The kinetic analysis of esterase inhibition by acylating compounds (organophosphorus carbamates and sulfonyl fluorides) is sometimes unable to yield consistent results by fitting simple inhibition kinetic models to experimental data of complex systems. In this work, kinetic data were obtained for phenylmethylsulfonyl fluoride (PMSF) tested at diffe...
Article
Full-text available
Some published studies suggest that low level exposure to organophosphorus esters (OPs) may cause neurological and neurobehavioral effects at long term exposure. These effects cannot be explained by action on known targets. In this work, the interactions (inhibition, spontaneous reactivation and "ongoing inhibition") of two model OPs (paraoxon, non...
Article
In this work kinetic data were obtained for different paraoxon concentrations incubated with chicken serum and the soluble fraction of chicken peripheral nerve. A kinetic model equation was deduced by assuming a multienzymatic system with three different simultaneously occurring molecular phenomena: (1) inhibition; (2) simultaneous spontaneous reac...
Article
The biotinylated organophosphorus compound 1-(saligenin cyclic phospho)-9-biotinyldiaminononane (S9B) has been used for the detection, labeling and isolation of the membrane-bound neuropathy target esterase (NTE) as it was considered a specific inhibitor of NTE. After incubation with the soluble fraction of chicken peripheral nerve, most of the sol...
Article
Type B carboxylesterases (acetylcholinesterases, neuropathy target esterase, serine peptidases), catalyse the hydrolysis of carboxyl-ester substrates by formation of a covalent acyl-enzyme intermediate and subsequent cleavage and release of the acyl group. Organophosphorus compounds, carbamates, and others exert their mechanism of neurotoxicity by...
Article
In the study of organophosphorus (OP) sensitive enzymes, careful discrimination of specific components within a complex multienzymatic mixture is needed. However, standard kinetic analysis gives inconsistent results (i.e., apparently different kinetic constants at different inhibitor concentration) with complex multienzymatic mixtures. A strategy i...
Article
Chicken serum, the usual in vivo animal for testing organophosphorus delayed neuropathy, has long been reported not to contain a homologous activity of the neuronal neuropathy target esterase (NTE) activity when it is assayed according to standard methods as the phenyl valerate esterase (PVase) activity, which is resistant to paraoxon and sensitive...
Article
Soluble extracts of chicken peripheral nerve contain detectable amounts of phenyl valerate esterase (PVase) activity (about 2000 nmol/min per g of fresh tissue). More than 95% of this activity is inhibited in assays where substrate has been added to a preincubated mixture of tissue with the non-neuropathic organophosphorus compound (OP) paraoxon (O...

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