Assessing the Therapeutic and Toxicological Profile of Novel Acetylcholinesterase Reactivators: Value of In Silico And In Vitro Data.

Organophosphorus compounds (OP) make up an important class of inhibitors, mostly employed as pesticides, even as chemical weapons. These toxic substances act through the inhibition of the acetylcholinesterase (AChE) enzyme, which results in elevated synaptic acetylcholine (ACh) levels, leading to serious adverse effects under the cholinergic syndrome. Many reactivators have been developed to combat the toxic effects of these AChE inhibitors. In this line, the oximes highlight because of their good reactivating power of cholinesterase enzymes. To date, no universal antidotes can reactivate AChE inhibited by any OP agent. This review summarizes the intoxication process by neurotoxic OP agents, along with the development of reactivators capable of reversing their effects, approaching aspects like the therapeutic and toxicological profile of these antidotes. Computational methods and conscious in vitro studies, capable of significantly predicting the toxicological profile of these drug candidates, might support the process of development of these reactivators before entering in vivo studies in animals, and then clinical trials. These approaches can assist in the design of safer and more effective molecules, reducing related cost and time for the process.

Novel fungal organophosphorus hydrolases in acidic media: an application to apples decontamination.

Organophosphorus pesticides bring significant improvements in agriculture, but their toxicity causes environmental and health negative impacts. The aim of this work was the development of robust biocatalysts to be applied in bioremediation. Four fungi were evaluated as hydrolase sources capable of degrading organophosphorus pesticides: Aspergillus niger, Fusarium sp., Penicillium chrysogenum, and Penicillium nalgiovense. The hydrolysis rates of methyl paraoxon obtained under acidic conditions were in the range of 10 to 21 mg L-1 d-1, which is remarkable since most similar biocatalysts are active under alkaline conditions. Penicillium chrysogenum activity was outstanding, and it was selected to prepare, characterize, and study the applications of its enzymatic extract. It was used to evaluate the bioremediation of apple surfaces at pH 2 in the presence of SDS, achieving complete methyl paraoxon degradation under proposed conditions. These results indicate that this biocatalyst could complement industrialized fruit washing processes for the elimination of organophosphorus pesticides.

Determination of organophosphorus compounds in water and food samples using a non-enzymatic electrochemical sensor based on silver nanoparticles and carbon nanotubes nanocomposite coupled with batch injection analysis.

This work presents, for the first time, a fast and highly sensitive electrochemical method for determination of three organophosphorus compounds (OPs), diazinon (DZN), malathion (MLT), and chlorpyrifos (CLPF), using a modified pyrolytic graphite electrode (PGE) coupled to batch injection analysis system with multiple pulse amperometric detection (BIA-MPA). The PGE was modified by a nanocomposite based on functionalized carbon nanotubes (CNTf) and silver nanoparticles (AgNPs). The OPs samples were directly analyzed on the modified working electrode surface by BIA-MPA system in Britton-Robinson (BR) buffer 0.15 mol L-1 at pH 6.0. The MPA detection of DZN, MLT and CLPF was performed using two potential pulses, which were sequentially applied on modified PGE at -1.3 V (100 ms) and +0.8 V (100 ms) for selective determination of these three OPs and working electrode cleaning, respectively. Under optimized conditions, the sensor presented a linear range of 0.1-20 µmol L-1 for DZN, 1.0-30 µmol L-1 for MLT and from 0.25 to 50 µmol L-1 for CLPF. The limits of detection (LOD) and quantification (LOQ) of 0.35 and 1.18 µmol L-1 for DZN, 0.89 and 2.98 µmol L-1 for MLT, and 0.53 and 1.78 µmol L-1 for CLPF were obtained. The proposed method exhibited high sensitivity of 0.068, 0.030 and 0.043 mA L µmol-1 for DZN, MLT and CLPF detection, respectively. Furthermore, the BIA-MPA system provided an analytical frequency of 71 determinations per hour for direct determination of these OPs in water and food samples. The modified PGE coupled to BIA-MPA system showed a high stability of electrochemical response for OPs detection with relative standard deviation (RSD) of 1.60% (n = 20). The addition-recovery studies of the proposed method were carried out in tap water, orange juice, and apple fruit real samples, which showed suitable recovery values between 77 and 124%. The analytical performance of the developed sensor provides an attractive alternative method for OPs determination with great potential for a fast and sensitive application in contaminated samples with these pesticides.

Theoretical and X-Ray Evidence of Electrostatic Phosphonium anti and gauche Effects.

Sulphur, not phosphorus, is the only known third-row element capable of experiencing an electrostatic gauche effect with fluorine. Some six-membered rings containing an endocyclic phosphorus atom and a ß-fluorine substituent that can interconvert to axial (gauche relative to phosphorus) and equatorial positions were then analysed. While phosphines do not establish an electrostatic attraction between fluorine and phosphorus, some oxidised forms exhibit surprising stability for the sterically disfavoured axial orientation. Because the nature of this behaviour was not obvious, since an intramolecular hydrogen bond can appear, a phosphonium derivative was further studied and its axial conformation was found to be highly stable. A preference for the gauche arrangement appears even for the acyclic and sterically hindered (2-fluoroethyl)triphenylphosphonium cation. On the other hand, (ethane-1,2-diyl)bis(phosphonium) cations are exclusively in anti conformation due to an (+/+)-electrostatic repulsion between the positively charged phosphonium groups.

Nucleophilic Neutralization of Organophosphates: Lack of Selectivity or Plenty of Versatility?

Neutralization of organophosphates is an issue of public health and safety, involving agrochemicals and chemical warfare. A promising approach is the nucleophilic neutralization, scope of this review, which focuses on the molecular nucleophiles: hydroxide, imidazole derivatives, alpha nucleophiles, amines and other nucleophiles. A reactivity mapping is given correlating the pathways and reaction efficiency with structural dependence of the nucleophile (basicity) and the organophosphate (electrophilic centers, P=O/P=S shift, leaving and non-leaving group). Reactions extremely unfavorable (>20 years) can be reduced to seconds with various nucleophiles, some which are catalytic. Although there is no universal nucleophile, a lack of selectivity in some cases accounts for plenty of versatility in other reactions. The ideal neutralization requires a solid mechanistic understanding, together with balancing factors such as milder conditions, fast process, selectivity and less toxic products.

Review about Structure and Evaluation of Reactivators of Acetylcholinesterase Inhibited with Neurotoxic Organophosphorus Compounds.

BACKGROUND: Neurotoxic chemical warfare agents can be classified as some of the most dangerous chemicals for humanity. The most effective of those agents are the Organophosphates (OPs) capable of restricting the enzyme Acetylcholinesterase (AChE), which in turn, controls the nerve impulse transmission. When AChE is inhibited by OPs, its reactivation can be usually performed through cationic oximes. However, until today, it has not been developed one universal defense agent, with complete effective reactivation activity for AChE inhibited by any of the many types of existing neurotoxic OPs. For this reason, before treating people intoxicated by an OP, it is necessary to determine the neurotoxic compound that was used for contamination, in order to select the most effective oxime. Unfortunately, this task usually requires a relatively long time, raising the possibility of death. Cationic oximes also display a limited capacity of permeating the Blood-Brain Barrier (BBB). This fact compromises their capacity to reactivating AChE inside the nervous system. METHODS: We performed a comprehensive search on the data about OPs available on the scientific literature today in order to cover all the main drawbacks still faced in the research for the development of effective antidotes against those compounds. RESULTS: Therefore, this review about neurotoxic OPs and the reactivation of AChE, provides insights for the new agents' development. The most expected defense agent is a molecule without toxicity and effective to reactivate AChE inhibited by all neurotoxic OPs. CONCLUSION: To develop these new agents, the application of diverse scientific areas of research, especially theoretical procedures as computational science (computer simulation, docking and dynamics), organic synthesis, spectroscopic methodologies, biology, biochemical and biophysical information, medicinal chemistry, pharmacology and toxicology, is necessary.

Microbial degradation of organophosphorus pesticides using whole cells and enzyme extracts.

The use of microbial phosphotriesterases in the degradation of organophosphorus compounds employed as pesticides, plasticizers and petroleum additives is a sustainable alternative for bioremediation of water and soils, decontamination of particular foods and as poisoning antidote. Whole cells of six wild type microorganisms-Streptomyces phaeochromogenes, Streptomyces setonii, Nocardia corynebacterioides, Nocardia asteroides and two Arthrobacter oxydans-selected in our lab as phosphotriesterase sources, were further tested as biocatalysts in the hydrolysis of paraoxon, methyl paraoxon, methyl parathion, coroxon, coumaphos, dichlorvos and chlorpyrifos, highlighting 98% conversion of chlorpyrifos into its hydrolysis products using whole cells of S. phaeochromogenes at pH 8 and 40 °C. Immobilized whole cells and enzyme extracts were also assessed, observing as a general trend, that there is no significant variation in hydrolytic activity between them. These results suggest that according to the circumstances, immobilized whole cells (avoiding cellular disruption and centrifugation) or enzyme extracts (which can be handled more easily) could be used.

Synthesis, antiinflammatory activity, and molecular docking studies of bisphosphonic esters as potential MMP-8 and MMP-9 inhibitors.

Bisphosphonic acids (or bisphosphonates) have been successfully used in the clinic treatment of bone diseases for over decades. Additionally, the antiinflammatory activity of these compounds has been gaining attention. In our previous work, we synthesized and in vivo evaluated the bisphosphonic esters 1 and 2, finding a moderate edema inhibition upon oral and topical administration on BALB/c mice. Thus, in this work, the bioisosteric replacement of an amide functional group for an ester afforded the new bisphosphonates 3-6, which had a moderate oral edema inhibition (25 mg/kg dose) and a significant topical antiinflammatory activity (2 mg/ear) on BALB/c mice, with 6 being the most active hit (55.9% edema inhibition), comparable to the positive control (55.5% edema inhibition) on a TPA topical model. Next, to assess the acute toxicity of the synthesized derivatives, test animals were administered with 50-100 mg/kg of 3-6, respectively, by an oral route, and after 14 days, neither lethality nor a significative weight loss were observed. Finally, a structure-activity relationship (SAR) and a molecular docking analysis of 3-6 helped us to explain the trend observed in biological tests. Considering all these aspects, we propose the inhibition of MMP-8 and MMP-9 as a possible action mechanism of the synthesized derivatives.

Trends in the Recent Patent Literature on Cholinesterase Reactivators (2016-2019).

Acetylcholinesterase (AChE) is the key enzyme responsible for deactivating the ACh neurotransmitter. Irreversible or prolonged inhibition of AChE, therefore, elevates synaptic ACh leading to serious central and peripheral adverse effects which fall under the cholinergic syndrome spectra. To combat the toxic effects of some AChEI, such as organophosphorus (OP) nerve agents, many compounds with reactivator effects have been developed. Within the most outstanding reactivators, the substances denominated oximes stand out, showing good performance for reactivating AChE and restoring the normal synaptic acetylcholine (ACh) levels. This review was developed with the purpose of covering the new advances in AChE reactivation. Over the past years, researchers worldwide have made efforts to identify and develop novel active molecules. These researches have been moving farther into the search for novel agents that possess better effectiveness of reactivation and broad-spectrum reactivation against diverse OP agents. In addition, the discovery of ways to restore AChE in the aged form is also of great importance. This review will allow us to evaluate the major advances made in the discovery of new acetylcholinesterase reactivators by reviewing all patents published between 2016 and 2019. This is an important step in continuing this remarkable research so that new studies can begin.

Biodegradation of Organophosphorus Compounds Predicted by Enzymatic Process Using Molecular Modelling and Observed in Soil Samples Through Analytical Techniques and Microbiological Analysis: A Comparison.

Organophosphorus compounds (OP) are chemicals widely used as pesticides in different applications such as agriculture and public health (vector control), and some of the highly toxic forms have been used as chemical weapons. After application of OPs in an environment, they persist for a period, suffering a degradation process where the biotic factors are considered the most relevant forms. However, to date, the biodegradation of OP compounds is not well understood. There are a plenty of structure-based biodegradation estimation methods, but none of them consider enzymatic interaction in predicting and better comprehending the differences in the fate of OPs in the environment. It is well known that enzymatic processes are the most relevant processes in biodegradation, and that hydrolysis is the main pathway in the natural elimination of OPs in soil samples. Due to this, we carried out theoretical studies in order to investigate the interactions of these OPs with a chosen enzyme-the phosphotriesterase. This one is characteristic of some soils' microorganisms, and has been identified as a key player in many biodegradation processes, thanks to its capability for fast hydrolyzing of different OPs. In parallel, we conducted an experiment using native soil in two conditions, sterilized and not sterilized, spiked with specific amounts of two OPs with similar structure-paraoxon-ethyl (PXN) and O-(4-nitrophenyl) O-ethyl methylphosphonate (NEMP). The amount of OP present in the samples and the appearance of characteristic hydrolysis products were periodically monitored for 40 days using analytical techniques. Moreover, the number of microorganisms present was obtained with plate cell count. Our theoretical results were similar to what was achieved in experimental analysis. Parameters calculated by enzymatic hydrolysis were better for PXN than for NEMP. In soil, PXN suffered a faster hydrolysis than NEMP, and the cell count for PXN was higher than for NEMP, highlighting the higher microbiological toxicity of the latter. All these results pointed out that theoretical study can offer a better comprehension of the possible mechanisms involved in real biodegradation processes, showing potential in exploring how biodegradation of OPs relates with enzymatic interactions.

Non-conventional compounds with potential therapeutic effects against Alzheimer's disease.

INTRODUCTION: Alzheimer's disease (AD) is the most common cause of dementia. Clinical progress in this pathogenesis field has drawn the attention of researchers, stimulating the investigation of novel treatment methods. Current therapies that deal with cholinesterase inhibitors and/or NMDA antagonists have shown a modest symptomatic potential, increasing the need for research into more efficient therapeutics. The goal of this review is to summarize the advances in, and the potential of, non-conventional therapies in AD treatment. Areas covered: In this review, the authors describe the current status of unusual therapies in AD treatment, evaluating the modern scientific contexts in which these therapies have been developed. The authors also highlight the usage of methylene blue, natural products, organophosphorus compounds, and Chinese medicine, along with the employment of nanotechnology. Expert opinion: The potential therapies discussed in this review will play increasingly important roles in the prevention and treatment of AD, improving disease management and quality of life for AD patients. Given the annual increasing number of people with dementia, it is crucial to invest in the search for novel therapeutics. In addition, more sophisticated diagnosis techniques are also essential, to allow for an early diagnosis and treatment.

Intoxicación por organofosforados / Organophospate poisoning

Resumen La intoxicación por organofosforados es de gran importancia en el campo de la medicina, debido a su uso frecuente en la actividad agrícola, las intoxicaciones producidas por estos agentes pueden ser ocupacionales, accidentales, y con mayor frecuencia por ingesta voluntaria. Una de las mayores repercusiones de los organofosforados es la inhibición del acetil colinesterasa, enzima encargada de hidrolizar el acetil colina. Las manifestaciones clínicas de la intoxicación aguda se deben a la estimulación de receptores muscarínicos y nicotínicos, entre ellas broncorrea, salivación, lagrimeo, broncoespasmo, defecación, emesis, miosis, entre otros. El diagnóstico se realiza mediante la historia clínica y examen físico, de manera adicional con la detección de los niveles en sangre eritrocitaria de acetil colinesterasa o de los metabolitos de los organofosforados. El manejo incluye la descontaminación del agente, la revisión del estado respiratorio y el acceso al soporte ventilatorio, posteriormente se procede con el tratamiento farmacológico que incluye el uso de la atropina, pralidoxima y diazepam. El presente artículo constituye una revisión bibliográfica sobre la intoxicación por organofosforados, sus manifestaciones clínicas, diagnóstico y tratamiento.

Abstract Organophosphorus poisoning is of great importance in the field of medicine due to its frequent use in agriculture, the poisoning by exposure to these agents can be occupational, accidental, and frequently due to voluntary intake. Organophosphorus' intake most notable effects are produced by the inhibition of the acetyl cholinesterase, responsible for hydrolyzing acetyl choline. Clinical manifestations of acute intoxication typically include bronchorrhea, salivation, lacrimation, bronchospasm, defecation, emesis, miosis, among others and they occur due to the stimulation of muscarinic and nicotinic receptors. Diagnosis is made through the interrogation and physical examination, in addition to the detection of acetyl cholinesterase levels or the organophosphates' metabolites in blood testing. Management includes decontamination of the agent, review of respiratory status and access to ventilatory support, followed by pharmacological treatment that includes the use of atropine, pralidoxime and diazepam. The present article constitutes a bibliographic review about the organopho sphorus intoxication, its clinical manifestations, diagnosis and treatment.

Asymmetric biodegradation of the nerve agents Sarin and VX by human dUTPase: chemometrics, molecular docking and hybrid QM/MM calculations.

Organophosphorus compounds (OP) nerve agents are among the most toxic chemical substances known. Their toxicity is due to their ability to bind to acetylcholinesterase. Currently, some enzymes, such as phosphotriesterase, human serum paraoxonase 1 and diisopropyl fluorophosphatase, capable of degrading OP, have been characterized. Regarding the importance of bioremediation methods for detoxication of OP, this work aims to study the interaction modes between the human human deoxyuridine triphosphate nucleotidohydrolase (dUTPase) and Sarin and VX, considering their Rp and Sp enantiomers, to evaluate the asymmetric catalysis of those compounds. In previous work, this enzyme has shown good potential to degrade phosphotriesters, and based on this characteristic, we have applied the human dUTPase to the OP degradation. Molecular docking, chemometrics and mixed quantum and molecular mechanics calculations have been employed, showing a good interaction between dUTPase and OP. Two possible reaction mechanisms were tested, and according to our theoretical results, the catalytic degradation of OP by dUTPase can take place via both mechanisms, beyond being stereoselective, that is, dUTPase cleaves one enantiomer preferentially in relation to other. Chemometric techniques provided excellent assistance for performing this theoretical investigation. The dUTPase study shows importance by the fact of it being a human enzyme. Communicated by Ramaswamy H. Sarma.

The Role of the Phosphorus Atom in Drug Design.

Although the phosphorus atom is found in a variety of oxidation states, most of the phosphorus-containing molecules of pharmacological importance possess phosphorus in the form of phosphonate or phosphinate functional groups, or in a major oxidation state as a phosphate group. The most common occurrence of phosphorus in drugs is either in prodrugs or in compounds for which the phosphorus atom plays a role in the biological activity, such as in modified nucleotides, in metabolically stable analogues of metabolites bearing phosphate groups, and as bioisosteric analogues of carboxyl groups.

Theoretical Studies Applied to the Evaluation of the DFPase Bioremediation Potential against Chemical Warfare Agents Intoxication.

Organophosphorus compounds (OP) are part of a group of compounds that may be hazardous to health. They are called neurotoxic agents because of their action on the nervous system, inhibiting the acetylcholinesterase (AChE) enzyme and resulting in a cholinergic crisis. Their high toxicity and rapid action lead to irreversible damage to the nervous system, drawing attention to developing new treatment methods. The diisopropyl fluorophosphatase (DFPase) enzyme has been considered as a potent biocatalyst for the hydrolysis of toxic OP and has potential for bioremediation of this kind of intoxication. In order to investigate the degradation process of the nerve agents Tabun, Cyclosarin and Soman through the wild-type DFPase, and taking into account their stereochemistry, theoretical studies were carried out. The intermolecular interaction energy and other parameters obtained from the molecular docking calculations were used to construct a data matrix, which were posteriorly treated by statistical analyzes of chemometrics, using the PCA (Principal Components Analysis) multivariate analysis. The analyzed parameters seem to be quite important for the reaction mechanisms simulation (QM/MM). Our findings showed that the wild-type DFPase enzyme is stereoselective in hydrolysis, showing promising results for the catalytic degradation of the neurotoxic agents under study, with the degradation mechanism performed through two proposed pathways.

Assessment of hematological parameters in workers exposed to organophosphorus pesticides, carbamates and pyrethroids in Cundinamarca 2016-2017 / Evaluación de parámetros hematológicos en trabajadores expuestos a pesticidas organofosforados, carbamatos y piretroides, Cundinamarca 2016-2017

ABSTRACT Objective To establish hematotoxic alterations through clinical and paraclinical exploration in workers who are exposed to organophosphorus pesticides, carbamates and pyrethroids (OPCP) due to their work in production, packaging, distribution and fumigation processes in Cundinamarca-Colombia between 2016 and 2017. Materials and Methods A cross-sectional descriptive epidemiological study was carried out on a sample of 92 workers from six companies, mostly aged between 18 and 30 years, of which 61 % were males and 39 % females, and 71 % were workers in the operational area and 29 % in the administrative area. Univariate, bivariate and multivariate analyses were performed. Results Clinical exploration reported findings in 17 % of the sample group, of which only 2 % presented with erythrocyte cholinesterase outside the reference range. The values of hematological parameters such as peripheral blood smear (PBS) and complete blood count (CBC) were outside the range in 15 % and 47 % of the sample, respectively. Discussion The results suggest that there are hematological alterations in this group that could possibly be associated with chronic exposure to OPCP.

RESUMEN Objetivo Determinar las alteraciones hematotóxicas a través de una exploración clínica y paraclínica, en trabajadores que por su oficio se exponen a pesticidas organofosforados, carbamatos y piretroides (POCP), en procesos de producción, envase, distribución y fumigación, en el departamento de Cundinamarca Colombia. Metodología Se realizó un estudio epidemiológico descriptivo de corte transversal. Se realizó un análisis univariado, bivariado y multivariado. La muestra se conforma por 92 trabajadores de seis empresas, la mayoría entre los 18 y 30 años, de los cuales el 61 % son hombres y el 39 % mujeres, 71 % se desempeñan en el área operativa y 29 % en el área administrativa. Resultados Es de resaltar que se tienen hallazgos en la exploración clínica en el 17 % del grupo participante, solo el 2 % presenta la colinesterasa eritrocitaria por fuera del rango de referencia. Los parámetros hematológicos como el frotis de sangre periférica (FSP) presentan valores por fuera de los rangos en el 15 % y el cuadro hemático (CH) tiene valores por fuera de los rangos en el 47 % de las personas. Discusión Los resultados sugieren que existen alteraciones hematológicas en este grupo y que posiblemente podrían estar asociadas con la exposición crónica a POCP.

Tremor essencial em guardas de endemias expostos a agrotóxicos: estudo caso-controle / Essential tremor in endemic disease control agents exposed to pesticides: a case-control study / Temblor esencial en empleados públicos del sector de vigilancia y control de endemias expuestos a pesticidas: estudio caso-control

Resumo: Tremor é o distúrbio do movimento mais frequente na população, e pode estar associado a exposição a agrotóxicos. O objetivo foi avaliar a chance de tremor essencial em 442 guardas de endemias do Estado do Rio de Janeiro, Brasil, expostos a agrotóxicos. Foram selecionados 51 casos e 204 controles (1:4). Todos os participantes responderam a um questionário sobre aspectos sociodemográficos, ocupacionais e toxicológicos. A influência da exposição a agrotóxicos sobre o desenvolvimento do tremor foi estimada por regressão logística não condicional, ajustada por covariáveis selecionadas. A idade média da população estudada foi de 49 (DP = 7) anos, sendo a diferença entre casos (média = 50,8; DP = 6,9) e controles (média = 48,5; DP = 6,9) estatisticamente significativa (p = 0,03). Além disso, aqueles com 16 a 16,9 anos de aplicação de agrotóxicos foram os que estiveram sob maior chance de apresentar a doença (OR ajustada = 4,60; IC95%: 1,29-16,41). Nossos resultados sugerem que o período entre 16 e 16,9 anos de aplicação de agrotóxicos teve impacto importante para o desenvolvimento dessa doença.

Abstract: Tremor is the most frequent movement disorder in the population and can be associated with pesticide exposure. The aim was to assess the odds of essential tremor in 442 endemic disease control agents in Rio de Janeiro State, Brazil, exposed to pesticides. Fifty-one cases and 204 controls were selected (1:4). All participants answered a questionnaire on socio-demographic, occupational, and toxicological items. The influence of pesticide exposure on the development of tremor was estimated by non-conditional logistic regression, adjusted for selected covariables. Mean age of the study population was 49 (SD = 7) years, and the difference between cases (mean = 50.8; SD = 6.9) and controls (mean = 48.5; SD = 6.9) was statistically significant (p = 0.03). Those with 16 to 16.9 years of pesticide use showed the highest odds of essential tremor (adjusted OR = 4.60; 95%CI: 1.29-16.41). Our results suggest that 16 to 16.9 years of pesticide exposure had a major impact on the development of essential tremor.

Resumen: El temblor es el disturbio de movimiento más frecuente en la población y puede estar asociado a la exposición a pesticidas. El objetivo fue evaluar la oportunidad del temblor esencial en 442 empleados públicos del sector de endemias del estado de Río de Janeiro, Brasil, expuestos a pesticidas. Se seleccionaron 51 casos y 204 controles (1:4). Todos los participantes respondieron a un cuestionario sobre aspectos sociodemográficos, ocupacionales y toxicológicos. La influencia de la exposición a pesticidas sobre el desarrollo del temblor fue estimada por regresión logística no condicional, ajustada por covariables seleccionadas. La edad media de la población estudiada fue de 49 (DP = 7) años, siendo la diferencia entre casos (media = 50,8; DP = 6,9) y controles (media = 48,5; DP = 6,9) estadísticamente significativa (p = 0,03). Además, aquellos de 16 a 16,9 años de servicio de fumigación con pesticidas fueron los que estuvieron bajo la mayor oportunidad de presentar la enfermedad (OR ajustada = 4,60; IC95%: 1,29-16,41). Nuestros resultados sugieren que el período entre 16 y 16,9 años de fumigación con pesticidas tuvo un impacto importante para el desarrollo de esa enfermedad.

New and highly active microbial phosphotriesterase sources.

Many toxic insecticides used worldwide as well as some chemical warfare agents are phosphotriester derivatives. Therefore, detoxification of organophosphorus compounds has become the subject of many studies and in particular bioremediation, based on the phosphotriesterase catalysed hydrolysis of these compounds, has shown to be an effective and ecological methodology. In order to identify new bacterial phosphotriesterases, a simple and sensitive fluorimetric screening method on solid media was employed that allowed the selection of six strains with phosphotriesterase activity. Since pH and temperature are important parameters for bioremediation of contaminated soils and waters, the influence of these variables on the rate of the enzymatic hydrolysis was assessed. This study afforded notable results, being the most remarkable one the increased activity exhibited by Nocardia asteroides and Streptomyces setonii strains at 50°C, 7 and 30 times higher than at 30°C, respectively. Compared with the results obtained with Brevundimonas diminuta, whose activity is usually considered as reference, an increase of 26 and 75 times is observed, respectively.

[Differential diagnosis from hyperglycemic ketoacidosis: pesticide poisoning. Clinical case]. / Diagnóstico diferencial de cetoacidosis hiperglicémica: intoxicación por plaguicidas. Caso clínico.

Diabetic ketoacidosis in children causes serious morbidity and mortality, especially if it is not recognized on time in the initial diagnosis. However, there are other diseases that can appear to be a metabolic disorder of this kind and be ignored if it is not suspected. We present a clinical case with hyperglycemic ketoacidosis due to the contact with organophosphate; we had to use a continuous infusion of insulin to control the metabolic disorder without repercussions after the girl came home.

La cetoacidosis diabética en niños puede ser una causa de morbilidad grave y mortalidad, especialmente si no se reconoce en el momento del primer diagnóstico. Sin embargo, existen otras patologías que pueden aparentar una alteración metabólica de este tipo y pasarse por alto si no se tiene sospecha clínica. A continuación, se describe un caso clínico que presenta cetoacidosis hiperglicémica debido al contacto con organofosforado, en el cual fue necesario el uso de insulina en infusión continua para el control del trastorno metabólico, sin repercusiones después del alta.

Diagnóstico diferencial de cetoacidosis hiperglicémica: Intoxicación por plaguicidas. Caso clínico / Differential diagnosis from hyperglycemic ketoacidosis: Pesticide poisoning. Clinical case

La cetoacidosis diabética en niños puede ser una causa de morbilidad grave y mortalidad, especialmente si no se reconoce en el momento del primer diagnóstico. Sin embargo, existen otras patologías que pueden aparentar una alteración metabólica de este tipo y pasarse por alto si no se tiene sospecha clínica. A continuación, se describe un caso clínico que presenta cetoacidosis hiperglicémica debido al contacto con organofosforado, en el cual fue necesario el uso de insulina en infusión continua para el control del trastorno metabólico, sin repercusiones después del alta.

Diabetic ketoacidosis in children causes serious morbidity and mortality, especially if it is not recognized on time in the initial diagnosis. However, there are other diseases that can appear to be a metabolic disorder of this kind and be ignored if it is not suspected. We present a clinical case with hyperglycemic ketoacidosis due to the contact with organophosphate; we had to use a continuous infusion of insulin to control the metabolic disorder without repercussions after the girl came home.