EVALUATION OF THE EFFICIENCY OF ALPHA-LIPOIC ACID AND IPIDACRINE HYDROCHLORIDE FOR THE PREVENTION OF PACLITAXEL-INDUCED PERIPHERAL NEUROPATHY ACCORDING TO THE TOTAL NEUROPATHY SCORE.

AIM: To evaluate the efficacy of combination of alpha-lipoic acid and acetylcholinesterase inhibitor (ipidacrine hydrochloride) to prevent the development and improve the course of paclitaxel-induced peripheral neuropathy (PIPN) in patients with breast cancer according to the Total Neuropathy Score. MATERIALS AND METHODS: 32 patients with breast cancer T1-4N0-3M0 received six cycles of polychemotherapy according to the AT scheme (paclitaxel, doxorubicin) or ET scheme (paclitaxel, epirubicin). Patients were randomized into two groups - without (group I) or with (group II) medication for prevention of neuropathy. A comprehensive neurological examination of patients was performed according to all ten parameters of the Total Neuropathy Score before chemotherapy, and after third and sixth cycles of chemotherapy. Each parameter was evaluated from 0 (no deficit) to 4 (no function/the most severe deficit). The scores obtained from the scale were summarized to obtain a total score from 0 to 40. RESULTS: The use of alpha-lipoic acid in combination with an acetylcholinesterase inhibitor (ipidacrine hydrochloride) significantly reduces the symptoms and severity of PIPN. The manifestations of PIPN in patients of the control group were significantly more severe compared to the group in which the study drugs were used. The average severity of neuropathy after 3 and 6 cycles was 1.75 and 2.62 in group I, and 1.12 and 1.62 - in group II, respectively (improvement by 15.75% (p < 0.05) and 25.00% (p < 0.001) after 3 and 6 cycles). CONCLUSIONS: Proposed combination of alpha-lipoic acid and ipidacrine hydrochloride led to a statistically significant reduction in the severity of PIPN, and thus to improvement of the functional capacity and quality of life of patients.

Behavioral, Biochemical and Histopathological effects of Standardised Pomegranate extract with Vinpocetine, Propolis or Cocoa in a rat model of Parkinson's disease.

INTRODUCTION: Parkinsonism is a neurodegenerative disorder. Pomegranate (POM) has been previously shown to have a dopaminergic neuroprotective effect against parkinsonism. OBJECTIVE: The aim of the current study is to investigate the possible effect of POM in combination with each of vinpocetine, propolis, or cocoa in the treatment of parkinsonism disease even without being given as adjuvant to L-dopa . METHODS: Rats were divided into seven groups, one normal and six RT model groups. One of the RT groups (2.5 mg/kg/48 h/10 doses sc), for 20 days served as non-treated parkinsonism model, whereas the others were treated with either L-dopa (10 mg/kg, p.o./day) or with POM (150 mg/kg, p.o./day) together with each of the following; vinpocetine (VIN) (20 mg/kg, p.o./day), propolis (300 mg/kg, p.o./day), cocoa (24 mg/kg, p.o./day). Motor and cognitive performances were examined using four tests (catalepsy, swimming, Y-maze, open field). Striatal dopamine, norepinephrine, serotonin, GABA, glutamate, acetylcholinesterase, GSK-3ß, BDNF levels were assessed as well as MDA, SOD, TAC, IL-1ß, TNF-α, iNOs, and caspase-3. Also, histopathological examinations of different brain regions were determined. RESULTS: Treatment with L-dopa alone or with all POM combination groups alleviated the deficits in locomotor activities, cognition, neurotransmitter levels, acetylcholinesterase activity, oxidative stress, and inflammatory markers as well as caspase-3 expression induced by RT. CONCLUSION: Combinations of POM with each of VIN, propolis, or cocoa have a promising disease-modifying antiparkinsonian therapy even without being given as an adjuvant to L-dopa.

Dihydromyricetin Improves Cognitive Impairments in d-Galactose-Induced Aging Mice through Regulating Oxidative Stress and Inhibition of Acetylcholinesterase.

SCOPE: Alzheimer's disease (AD) is a neurodegenerative disease with phenomena of cognitive impairments. Oxidative stress and cholinergic system dysfunction are two widely studied pathogenesis of AD. Dihydromyricetin (DMY) is a natural dihydroflavonol with many bioactivities. In this study, it is aimed to investigate the effects of DMY on cognitive impairment in d-galactose (d-gal) induced aging mice. METHODS AND RESULTS: Mice are intraperitoneally injected with d-gal for 16 weeks, and DMY is supplemented in drinking water. The results show that DMY significantly improves d-gal-induced cognitive impairments in novel object recognition and Y-maze studies. H&E and TUNEL staining show that DMY could improve histopathological changes and cell apoptosis in mice brain. DMY effectively induces the activities of catalase, superoxide dismutase and glutathione peroxidase, and reduces malondialdehyde level in mice brain and liver. Furthermore, DMY reduces cholinergic injury by inhibiting the activity of Acetylcholinesterase (AChE) in mice brain. In vitro studies show that DMY is a non-competitive inhibitor of AChE with IC50 value of 161.2 µg mL-1 . CONCLUSION: DMY alleviates the cognitive impairments in d-gal-induced aging mice partly through regulating oxidative stress and inhibition of acetylcholinesterase.

The Relationship Between Neuroprotective Activity and Antigenotoxic and Acetylcholinesterase Inhibitory Effects of Glaucium corniculatum Extracts

Abstract The purpose of this study was to investigate the relationship between the acetylcholinesterase (AChE) inhibitory and antigenotoxic effect with the neuroprotective activity of Glaucium corniculatum methanol and water extracts rich in rutin and quercetin flavonoids. Neuroprotective activity in terms of cell survival and development against oxidative damage was measured by MTT assay and microscopic analysis in H2O2-induced NGF-differentiated PC12 (dPC12) cells. QRT-PCR and western blot hybridization method was employed for the determination of AChE inhibition of the extracts in the same cell model, and the genotoxic and antigenotoxic effects were identified with Comet assay with human lymphocytes. H2O2-induced vitality loss in dPC12 cells was inhibited in pre-treated cells with these plant extracts. Moreover, extracts stimulated neurite formation and prevented the oxidative stress-induced reduction in neurite growth. In general, it was determined that G. corniculatum methanol extract containing higher amounts of rutin and quercetin was more effective than water extract in terms of AChE inhibitory, antigenotoxic and also neuroprotective effect. In this study, it was shown for the first time that both AChE inhibitory and antigenotoxic effects of G. corniculatum may be effective in neuroprotection and it's protective and therapeutic effects against neurodegeneration may be related to the flavonoid content.

Chemical profile, acetylcholinesterase, butyrylcholinesterase, and prolyl oligopeptidase inhibitory activity of Glaucium corniculatum subsp. refractum

Abstract Papaveraceae is one of the prominent alkaloid-containing families, and plants of the genus Glaucium (Papaveraceae) are known for their bioactive alkaloids. Glaucium species have been used in traditional medicine in Turkey as an analgesic, narcotic, sedative, and antitussive. In this study, it was planned to evaluate the inhibitory activity of an alkaloidal extract of Glaucium corniculatum subsp. refractum on acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and prolyl oligopeptidase (POP), as well as exploring the chemical profile of the plant by using Gas Chromatography-Mass Spectrometry (GC-MS). The AChE, BuChE and POP inhibition activities of the alkaloidal extract of G. corniculatum subsp. refractum were determined spectrophotometrically. A rapid GC-MS method was used to identify alkaloids that could be responsible for these inhibition activities. In total, eleven alkaloids were identified in the alkaloid extract of the plant by GC-MS. Allocyptopine (52.92%) and protopine (25.38%) were found as the major constituents. The alkaloidal extract of G. corniculatum subsp. refractum showed potent AChE inhibitory activity (IC50:1.25 µg/mL) and BuChE inhibitory activity (IC50: 7.02 µg/mL). The extract also showed a remarkable inhibitory effect on POP with an IC50 value of 123.69 µg/mL. This study presents the first GC-MS investigation and POP inhibitory activity of G. corniculatum subsp. refractum.

Ocotea daphnifolia: phytochemical investigation, in vitro dual cholinesterase inhibition, and molecular docking studies

This study aimed to evaluate the anticholinesterase activities of extracts and fractions of Ocotea daphnifolia in vitro and characterize its constituents. The effects of hexane, ethyl acetate, and ethanolic extracts on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity were determined with a spectrophotometry assay. All extracts inhibited cholinesterase activity, and the ethanolic extract (2 mg/mL) exhibited the highest inhibition of both enzymes (99.7% for BuChE and 82.4% for AChE). The ethanolic extract was fractionated by column chromatography resulting in 14 fractions that were also screened for their anticholinesterase effects. Fraction 9 (2 mg/mL) showed the highest activity, inhibiting AChE and BuChE by 71.8% and 90.2%, respectively. This fraction was analyzed by high-performance liquid chromatography high-resolution mass spectrometry which allowed the characterization of seven glycosylated flavonoids (containing kaempferol and quercetin nucleus) and one alkaloid (reticuline). In order to better understand the enzyme-inhibitor interaction of the reticuline toward cholinesterase, molecular modeling studies were performed. Reticuline targeted the catalytic activity site of the enzymes. Ocotea daphnifolia exhibits a dual cholinesterase inhibitory activity and displays the same pattern of intermolecular interactions as described in the literature. The alkaloid reticuline can be considered as an important bioactive constituent of this plant.

Chemical evaluation and anticholinesterase activity of Hippeastrum puniceum (Lam. ) Kuntz bulbs (Amaryllidaceae)

Hippeastrum puniceum is a species that belongs to the Amaryllidaceae family. A particular characteristic of this family is the consistent and very specific presence of isoquinoline alkaloids, which have demonstrated a wide range of biological activities such as antioxidant, antiviral, antifungal, antiparasitic, and acetylcholinesterase inhibitory activity, among others. In the present work, fifteen alkaloids were identified from the bulbs of Hippeastrum puniceum (Lam.) Kuntz using a GC-MS approach. The alkaloids 9-O-demethyllycoramine, 9-demethyl-2α-hydroxyhomolycorine, lycorine and tazettine were isolated through chromatographic techniques. The typical Amaryllidaceae alkaloids lycorine and tazettine, along with the crude and ethyl acetate extract from bulbs of the species were evaluated for their inhibitory potential on α-amylase, α-glucosidase, tyrosinase and acetylcholinesterase activity. Although no significant inhibition activity was observed against α-amylase, α-glucosidase and tyrosinase from the tested samples, the crude and ethyl acetate extracts showed remarkable acetylcholinesterase inhibitory activity. The biological activity results that correlated to the alkaloid chemical profile by GC-MS are discussed herein. Therefore, this study contributed to the knowledge of the chemical and biological properties of Hippeastrum puniceum (Lam.) and can subsidize future studies of this species

Métodos de extração, estabilidade e biodisponibilidade da guanitoxina em cultivos de Sphaeropermopsis torques-reginae analisadas por espectrometria de massas / Methods of extraction, stability, and bioavailability of guanitoxin in Sphaeropermopsis torques-reginae cultures analyzed by mass spectrometry

A guanitoxina (GNT) é uma neurotoxina produzida por algumas cepas de cianobactérias dos gêneros Dolichospermum e Sphaerospermopsis>. A GNT é o único organofosforado natural, capaz de causar a morte de animais selvagens e domésticos devido à inibição irreversível da acetilcolinesterase. Apesar de sua alta toxicidade, o diagnóstico da GNT em amostras biológicas ainda é um grande desafio. A dificuldade para sua detecção está diretamente ligada à sua instabilidade em altas temperaturas e pH alcalino, tornando difícil seu monitoramento em corpos d'água. Por isso, esta pesquisa objetivou estudar a estabilidade e biodisponibilidade da GNT em amostras aquosas, com intuito de obter mais informações sobre a natureza química e biológica dessa potente neurotoxina. Para realizar este estudo, a cepa ITEP-24 (S. torques-reginae) produtora de GNT foi cultivada em laboratório sob condições controladas, para obter biomassa para os experimentos de extração, semi-isolamento, estabilidade, ensaio in vitro e identificação por LC-MS/MS. Primeiramente foram realizados testes de extração da GNT partir de células liofilizadas da cepa ITEP-24 utilizando água, metanol e etanol em pH ácido. Depois utilizou-se dois métodos de extração em fase sólida (SPE) com cartuchos preenchidos com fases estacionarias C18 em fase reversa e sílica gel em fase normal, com objetivo de avaliar qual método de SPE seria melhor para extrair e concentrar a GNT. Nós também testamos métodos para lisar as células com sondas de ultrassom, misturador e centrifugação. Além dos métodos de extração, nós avaliamos a estabilidade da toxina em diferentes temperaturas, para isso a biomassa seca contendo a GNT ficou condicionada a 4 °C, 23 °C, -20 °C, -80 °C durantes seis meses, e análises de identificação foram realizadas dentro período de 150 dias em uma sequência de 30 dias. A estabilidade da toxina foi analisada também a partir de extrações em soluções com diferentes valores de pH (1,5; 3,0; 5,0; 7,0; 8,5; 10,5) e temperatura (23 ºC e 37 ºC). Depois, analisou-se a biodisponibilidade da GNT em células frescas da linhagem ITEP-24 através de teste de dissolução in vitro. O objetivo deste teste foi avaliar a liberação da toxina intracelular em meio simulado do conteúdo gástrica e intestinal com e sem enzimas digestivas para compreender e estimar a disponibilidade da GNT in vivo. Os resultados de todos experimentos descritos neste estudo, foram obtidos a partir de análises por cromatografia líquida de interação hidrofílica (HILIC) acoplado ao espectrômetro de massas do tipo triplo quadrupolo LC-QqQ-MS/MS utilizando as transições 253>58, 253>159 e 159>58 [M+H]+ utilizando coluna com fase estacionária zwitteriônica (ZIC). A identificação da GNT foi realizada também por cromatografia líquida acoplada ao espectrômetro de massas de alta resolução (LC-HR-QTOF-MS) com coluna Luna C18, Hydro-RP C18 e ZIC-HILIC. Dos protocolos de extração testados, a combinação de metanol/água (70:30 v/v) com ácido acético (0.3%) extraiu maior quantidade relativa da GNT a partir de células frescas e liofilizadas da cepa ITEP-24 e a concentração da toxina foi maior em amostras de células frescas. Em relação aos métodos de lise celular, as extrações realizadas em sonda de ultrassom com banho-maria e centrifugação por 1h foram estatisticamente significantes para liberar a toxina intracelular. Não houve diferença significativa entre os testes de SPE, no entanto, a semipurificação da toxina foi melhor com cartucho preenchido com sílica gel em fase normal e adaptação desse método em coluna aberta permitiu obter uma fração enriquecida com GNT. A GNT mostrou ser mais estável em pH ácido, sendo o pH 3,0 o melhor para manter e extrair a toxina em amostras aquosas e a toxina intracelular presente em células secas podem degradar em temperatura de 23 °C por um período de 150 dias mesmo em solução com pH 3,0. Durante os testes de extração e purificação foi observado também a degradação da toxina em processos de secagem e ressuspensão. As análises realizadas no LC-HR-QTOF-MS com diferentes métodos cromatográficos possibilitou a identificação da GNT, porém o método realizado com coluna ZIC-HILIC mostrou melhor resolução cromatográfica dos picos relativos m/z e tempo de retenção de toxina. Os resultados obtidos nos testes de dissolução in vitro mostraram que a GNT fica mais disponível no simulado gástrico com e sem a enzima pepsina, mas também pode ser absorvida no intestino. Portanto, o teste de dissolução in vitro pode ser uma ferramenta útil para a avaliação de risco de cianotoxinas in vivo, devido ao seu potencial de monitorar qualitativa e quantitativamente substâncias dissolvidas em fluidos gastrointestinais. Os resultados apresentados neste estudo fornecem informações valiosas para uma melhor compreensão da estabilidade e biodisponibilidade do GNT. Além disso, os métodos apresentados neste estudo podem ser úteis para diversas aplicações projetadas para identificar a toxina em amostras ambientais, bem como orientações para procedimentos de purificação da GNT

Guanitoxin (GNT) is a neurotoxin produced by some strains of cyanobacteria of the genus Dolichospermum and Sphaerospermopsis. GNT is the only natural organophosphate, capable of causing the death of animals from wild and domestic animals due to irreversible inhibition of acetylcholinesterase. Despite its high toxicity, the diagnosis of GNT in biological samples is still a significant challenge. The difficulty in its detection is directly linked to its instability at high temperatures and alkaline pH, making it difficult to monitor in bodies of water. Therefore, this research aimed to study the stability and bioavailability of GNT in aqueous samples to provide more information about the chemical and biological nature of this molecule. The strain ITEP-24 (S. torques-reginae) producing GNT was grown in the laboratory under controlled conditions to obtain biomass for the extraction, semi-isolation, stability, in vitro tests, and toxin identification by LC-MS/MS. Firstly, tests were carried out to extract GNT from lyophilized cells strain ITEP-24 using water, methanol, and ethanol at acidic pH and, two SPE methods in cartridges with stationary phases of C18 reverse phase and normal phase gel silica, to evaluate which would be better to extract and concentrate the GNT. We also tested different methods of cell lysis, such as ultrasound probes, mixers, and centrifugation. In addition to the extraction methods, the stability of the toxin was evaluated at different temperatures, for this, the dry biomass containing the toxin was conditioned at 4 °C, 23 °C, -20 °C, -80 °C for 150 days and analysis of the identification of the GNT was carried out within that period in a sequence of 30 days. The toxin stability was also analyzed from extractions in solutions with different pH values (1.5; 3.0; 5.0; 7.0; 8.5; 10.5) and temperature (23 ºC and 37 ºC). In addition, we performed dissolution tests with fresh cells of the ITEP-24 strain to evaluate the bioavailability of GNT in simulated gastric and intestinal fluids with and without digestive enzymes to understand and estimate the availability of GNT in vivo. The results of all experiments described in this study were obtained from analyzes by hydrophilic interaction liquid chromatography (HILIC) coupled to the LC-QqQ-MS/MS triple quadrupole mass spectrometer using the transitions m/z 253> 58, m/z 253> 159 and m/z 159> 58 [M + H]+ using a column with the zwitterionic stationary phase (ZIC). Liquid chromatography coupled to the high-resolution mass spectrometer (LC-HR-QTOF-MS) with Luna column C18, Hydro-RP C18, and ZIC-HILIC carried out the identification of the GNT. From the extraction protocols tested, the combination of methanol/water (70:30 v/v) with acetic acid (0.3%) extracted a greater relative amount of GNT from fresh and lyophilized ITEP-24 cells, and the concentration of the toxin is higher previously fresh. Concerning cellular methods, the ultrasound probe with a water bath and centrifugation for 1h ware statistically significant to release the intracellular toxin. There was no significant difference between the SPE tests. However, the semi-purification of the toxin was better with a cartridge filled with gel silica in the normal phase and adaptation of this method in an open column allowed to obtain a fraction enriched with GNT. GNT was more stable at acid pH, with pH 3.0 being the best to maintain and the intracellular toxin present in dry cells can degrade at a temperature at 23 °C for 150 days even in pH 3.0 solution. The toxin can also hydrolyze in the drying and resuspension processes. The analyzes carried out in LC-HR-QTOF-MS with different chromatographic methods made it possible to identify the GNT itself, however, the ZIC-HILIC column method showed excellent chromatographic resolution of the relative m/z peaks and toxin retention time. The results obtained in the in vitro dissolution tests showed that GNT is more available in the gastric simulation with and without the enzyme pepsin, but it can also be absorbed in the intestine. Thus, in vitro dissolution tests can be used as a useful tool for the risk assessment of cyanotoxins in vivo due to their potential to qualitatively and quantitatively monitor substances dissolved in gastrointestinal fluids. The results presented in this study provide valuable information for a better understanding of the stability and bioavailability of GNT. Besides, the methods presented in this study can be useful for various applications designed to identify the toxin in environmental samples, as well as guidance on procedures for purifying GNT

Preclinical and first-in-human evaluation of PRX-105, a PEGylated, plant-derived, recombinant human acetylcholinesterase-R.

PRX-105 is a plant-derived recombinant version of the human 'read-through' acetylcholinesterase splice variant (AChE-R). Its active site structure is similar to that of the synaptic variant, and it displays the same affinity towards organophosphorus (OP) compounds. As such, PRX-105 may serve as a bio-scavenger for OP pesticides and chemical warfare agents. To assess its potential use in prophylaxis and treatment of OP poisoning we conducted several preliminary tests, reported in this paper. Intravenous (IV) PRX-105 was administered to mice either before or after exposure to an OP toxin. All mice who received an IV dose of 50nmol/kg PRX-105, 2min before being exposed to 1.33×LD50 and 1.5×LD50 of toxin and 10min after exposure to 1.5×LD50 survived. The pharmacokinetic and toxicity profiles of PRX-105 were evaluated in mice and mini-pigs. Following single and multiple IV doses (50 to 200mg/kg) no deaths occurred and no significant laboratory and histopathological changes were observed. The overall elimination half-life (t½) in mice was 994 (±173) min. Additionally, a first-in-human study, to assess the safety, tolerability and pharmacokinetics of the compound, was conducted in healthy volunteers. The t½ in humans was substantially longer than in mice (average 26.7h). Despite the small number of animals and human subjects who were assessed, the fact that PRX-105 exerts a protective and therapeutic effect following exposure to lethal doses of OP, its favorable safety profile and its relatively long half-life, renders it a promising candidate for treatment and prophylaxis against OP poisoning and warrants further investigation.

Enfermedad de Alzheimer: Tratamientos actuales y futuros / Alzheimer's Disease: Current and Future Treatments

Unas 25 millones de personas padecen enfermedad de Alzheimer en el mundo, y probablemente en los práximos 20 años, se registrarán unos 70 millones de nuevos casos. Caracterizaada por una pérdida progresiva de la memoria, el déficit de la capacidad cognitiva es proporcional a la densidad de placas seniles, a la acumulación de la proteína beta amiloide, degeneraciones neuríticas y ovillos neurofibrilares, particularmente en el hipocampo y en la corteza cerebral. Este cuadro histopatológico se asocia a otro neuroquímico, caracterizado por una disminución de las enzimas colina acetiltransferasa y acetilcolinesterasa, y una menor densidad de los receptores colinérgicos muscarínicos y nicotínicos. Ello ha generado la teoría colinérgica del Alzheimer, que ha dado lugar a una aproximación racional al tratamiento de la enfermedad. Hoy disponemos de 3 anticolinesterásicos, galantamina, donepecilo y rivastigmina aprobados por FDA, que se recomiendan en EA leves y moderadas y de un antagonista no competitovo de los receptores NMDA memantina EA. El beneficio es modesto en relación a lo cogitivo y conductual. Se incluyen estudios sobre recomendaciones, farmacología, farmacognética, eficacia, tolerancia, características de los pacientes respondedores a los diferentes anticolinesterásicos, sus reemplazos el uso de comprimidos, parches, beneficiios, efectos adversos y de las nuevas terapéuticas que están en desarrollo como estanercept, NP12, resveratrol PBT2 y vacuna nasal, entre otras...

About 25 millions of individuals in the world suffer from Alzheimer's disease. The next 20 years shall probably register 70 millions of new cases. Characterized by a progressive loss of memory, cognitive deficit is proportional to the density of senile plaques, accumulation of beta amyloid, neuritic degeneration and neurofibrillary tangles, particularly in the hippocampus and cerebral cortex. This histopathological condition is associated with another neurochemical, chracterized by a decrease in choline acetyltransferase and acetylcholinesterase enzymes, and a lower density of muscrinic and nicotinic cholinergic receptors. This results in the cholinergic theory of Alzheimer's, which has led to a rational approach to treatment of disease. Today we have 3 anticholinesterase Galantamine, Donepzil and Rivastigmine approved by FDA recommended in mild to moderate AD and an uncompetitive antagonist of NMDA receptors Memantine is recommended in mild Alzheimer's disease for people who can not take ACE inhibitors, and severe AD The benefit is modest in realtion to the cognitive and behavioral. Studies are included on therapeutic recommendations, pharmacology, pharmacogenetic, efficiency, tolerance, characteristics of responders to different anticholinesterases, their relacements, the use of pills, patches, benefits, side effects and new therapeutic under development as Etanercept, NP12, PBT 2, Resveratrol, Nasal Vaccine, among others...

Homodimeric bis-quaternary heterocyclic ammonium salts as potent acetyl- and butyrylcholinesterase inhibitors: a systematic investigation of the influence of linker and cationic heads over affinity and selectivity.

A molecular library of quaternary ammonium salts (QASs), mainly composed of symmetrical bis-quaternary heterocyclic bromides exhibiting choline kinase (ChoK) inhibitory activity, were evaluated for their ability to inhibit acetyl- and butyrylcholinesterase (AChE and BChE, respectively). The molecular framework of QASs consisted of two positively charged heteroaromatic (pyridinium or quinolinium) or sterically hindered aliphatic (quinuclidinium) nitrogen rings kept at an appropriate distance by lipophilic rigid or semirigid linkers. Many homodimeric QASs showed AChE and BChE inhibitory potency in the nanomolar range along with a low enzymatic selectivity. Computational studies on AChE, BChE, and ChoK allowed identification of the key molecular determinants for high affinity and selectivity over either one of the three enzymes and guided the design of a hybrid bis-QAS (56) exhibiting the highest AChE affinity (IC(50) = 15 nM) and selectivity over BChE and ChoK (SI = 50 and 562, respectively) and a promising pharmacological potential in myasthenia gravis and neuromuscular blockade.

Exposição ocupacional e ambiental a agrotóxicos e nicotina na cultura de fumo do município de Arapiraca, AL / Occupational and Environmental Exposure to Pesticides and Nicotine in Tobacco Culture of the Municipality of Arapiraca / AL

No Brasil, o cultivo do tabaco é associado a graves problemas de saúde entre os agricultores, e que podem evoluir para um quadro de depressão e suicídio. A exposição de trabalhadores rurais a agrotóxicos em culturas de tabaco é, na maioria das vezes, tratada como um evento isolado, desconsiderando-se a exposição concomitante a outras substâncias, como a nicotina, presente nas folhas de tabaco. O presente trabalho tem como objetivo analisar as exposições ocupacionais e ambientais a agrotóxicos e nicotina na cultura de tabaco do município de Arapiraca, AL, com ênfase nos efeitos dessas exposições sobre a atividade da enzima acetilcolinesterase (AChE). A partir do conhecimento do processo de trabalho local, um grupo de 72 fumicultores do município foram avaliados com relação exposição a agrotóxicos organofosforados (OP) e carbamatos e à nicotina nos períodos de cultivo e entre-safra do tabaco. A exposição a agentes anticolinesterásicos foi avaliada através da análise da atividade da AChE eritrocitária, enquanto a exposição à nicotina foi avaliada através dos níveis plasmáticos de cotinina. Um grupo composto por 45 indivíduos foi utilizado como controle na comparação da atividade da AChE. Complementarmente, avaliou-se o efeito in vitro da exposição à nicotina e a OP sobre a atividade da AChE. A análise dos resultados mostrou que, nos testes in vitro, a nicotina somente inibiu a AChE em concentrações iguais ou superiores a 0,5mM. A nicotina não apresentou efeito aditivo nas inibições da AChE por etil paroxon in vitro. (...) Seis indivíduos não fumantes apresentaram valores de cotinina entre 50 e 200 ng/mL, caracterizando uma exposição ocupacional a nicotina. A análise dos resultados in vivo mostrou que os níveis de cotinina plasmático apresentado pelos agricultores não têm correlação com a atividade da AChE. Isto aponta para a possibilidade da não ocorrência de um efeito aditivo da exposição à nicotina e agrotóxicos sobre a atividade da AChE, fator que pode ser utilizado para um diagnóstico diferencial entre a exposição a agrotóxicos e à nicotina entre trabalhadores da cultura fumageira.

Anticorpos aviários como reagentes para o diagnóstico da intoxicação humana por organofosforados / Avian antibodies as reagents for diagnosis of human poisoning by organophosphorus

Os agrotóxicos são substâncias usadas para exterminar pragas ou doenças quecausam danos às plantações. Os organofosforados são agrotóxicos responsáveis por 70 por cento das intoxicações ocupacionais e atuam inibindo a enzima acetilcolinesterase por meio da fosforilação do aminoácido serina do sítio ativo. Existem diversos métodos de diagnóstico para monitorar a exposição a estes compostos, tais como: identificação e análise quantitativa de compostos livres noplasma; identificação e análise quantitativa de metabólitos na urina; determinação da atividade de colinesterases no plasma ou no sangue total. Entretanto, estas metodologias possuem algumas limitações, como por exemplo, a falta de especificidade, tecnologias de análise caras e variações interindividuais (sexo, idade, etc.). Uma tentativa de contornar estas limitações na quantificação da atividade de colinesterases é o desenvolvimento de metodologias baseadas na detecção da enzima fosforilada através de técnicas imunoquímicas. Este estudo teve como objetivo desenvolver um método de imunoensaio para o diagnósticorápido da exposição humana aos organofosforados pela detecção deacetilcolinesterase inibida no sangue humano por anticorpos aviários produzidos contra uma sequência de aminoácidos ao redor da serina fosforilada do centro catalítico da enzima. Para isto, foram adquiridos dois decapeptídeos sintéticos correspondentes ao sítio catalítico "não fosforilado" (SOH) e outro com o resíduo de serina fosforilado (SOP). Estes peptídeos foram conjugados com albumina bovina de soro (BSA), injetados em galinhas poedeiras da raça Isa-Brown e anticorpos IgY foram obtidas das gemas dos ovos das galinhas imunizadas. A especificidade dos anticorpos IgY anti-SOH e anti-SOP foi testada por meio de métodos ELISA constatando-se que estes anticorpos reconhecem os peptídeos livres, os peptídeos conjugados com BSA e a própria BSA...

Effects of estrogen on intracellular signaling pathways linked to activation of muscarinic acetylcholine receptors and on acetylcholinesterase activity in rat hippocampus

The aim of the present study was to investigate the effects of estrogen lack and estrogen replacement on the production of total [3H]inositol phosphate ([3H]IP) induced by the activation of muscarinic acetylcholine receptors (mAChRs) and on the mechanisms for inactivation of acetylcholine. Hippocampi were obtained from rats in proestrus (PE), ovariectomized for 15 days (C15), ovariectomized for 15 days and then treated with 17â-estradiol for 7 days (E7) and ovariectomized and immediately treated with 17â-estradiol for 21 days (E21). Ovariectomy did not change the basal level of total [3H]IP in the hippocampus. 17â-Estradiol replacement (E7 and E21) reduced the basal level of total [3H]IP. In all experimental groups, carbachol (CCh) caused a concentration-dependent rise in total [3H]IP. The maximum effect was reached with 10-4 M CCh. The response to 10-4 M CCh in the hippocampi from C15 and E7 rats was twofold higher than in hippocampi from PE and E21 animals and was blocked by pirenzepine, but not by methoctramine. Ovariectomy or 17â-estradiol treatment for 7 days did not change neither the total acetylcholinesterase (AChE) activity nor the relative amount of mono- and dimeric G1/G2 and tetrameric G4 globular forms. Conversely, hormonal treatment for 21 days induced an increase in AChE activity of G1/G2 and G4 forms, indicating that 17â-estradiol stimulates both synthesis and assembly of AChE molecular forms. The present results suggest that the duration and/or a critical period with regard to the initiation of estrogen therapy are important to regulate the function of mAChRs and AChE activity in female rat hippocampus.

Effects of endosulfan sublethal concentrations oncarp (Cyprinus carpio, Linnaeus, 1758): Morphometric, hystologic, ultrastructural analysesand cholinesterase activity evaluation / Efeitos do endosulfano em concentrações subletais em carpas (Cyprinuscarpio, Linnaeus, 1758): Análises morfométricas, histológicas eultraestrutural e avaliação da atividade da colinesterase

Endosulfan, an organochlorine pesticide, has been banned by most developed countries, although it is still produced, sold and used in developing countries. Used for control in crops, as well as for insect control in public health programs in some countries, its effects on the environment and its toxicity are still in discussion. For some researchers, its bioaccumulation in terrestrial organisms is considered irrelevant but for aquatic life it should be considered carefully. The present research work was to carry out an study on the effects of sublethal concentrations of endosulfan on the fresh water fish carp (Cyprinus carpio, Linnaeus, 1758). The fishes were exposed during 15 days to 0.001 mg/L of endosulfan using dimethylsulfoxide 0.1% (DMSO) as solvent. The acetylcholinesterase activity on the brain and axial muscle, as well as liver morphometric, histopathologic and ultrastructural analysis were studied. The hepatic somatic index and the livers weight showed smaller values when compared with the control groups, besides being also observed histopathological and ultrastructural alterations. It has not been observed significant alterations in the cholinesterase activity of both brain and striated muscle. These results suggest that the organochloride endosulfan caused toxic effects in the hepatic metabolism of the fish exposed to it in sub lethal doses

Endosulfano, um pesticida organoclorado, tem sido banido pela maioria dos países desenvolvidos, embora seja ainda produzido e utilizado deliberadamente em países em desenvolvimento. Utilizado no controle de pragas, assim como no controle de insetos em Programas de Saúde Pública em alguns países, seus efeitos no meio ambiente e sua toxicidade continuam em discussão. Para alguns pesquisadores a bioacumulação nos organismos terrestres é considerada irrelevante, mas não para a vida aquática. O objetivo da presente pesquisa foi estudar os efeitos das concentrações subletais do endosulfano em peixes de água doce Cyprinus carpio, (Linnaeus, 1758). Os peixes foram expostos durante 15 dias, a uma concentração de 0,001mg/L de endosulfano utilizando o dimetilsulfóxido (DMSO) a 0,1% como solvente. A atividade da acetilcolinesterase do músculo axial e cerebral assim como a morfometria, histopatologia e a ultraestrutura do fígado desses peixes foram avaliadas. O índice somático hepático e o peso dos fígados mostraram valores menores quando comparados ao grupo controle, observando-se também, alterações histopatológicas e ultraestruturais. Nenhuma alteração significante na atividade da acetilcolinesterase muscular e cerebral foram observadas. Os resultados sugerem que o organoclorado endosulfano causou efeitos tóxicos no metabolismo hepático dos peixes expostos a doses subletais

Biomarkers of intermediate endpoints in environmental and occupational health.

The use of biomarkers in environmental and occupational health is increasing due to increasing demands on information about health risks from unfavourable exposures. Biomarkers provide information about individual loads. Biomarkers of intermediate endpoints benefit in comparison with biomarkers of exposure from the fact that they are closer to the adverse outcome in the pathway from exposure to health effects and may provide powerful information for intervention. Some biomarkers are specific, e.g., DNA and protein adducts, while others are unspecific like the cytogenetic biomarkers of chromosomal aberrations (CA), sister chromatid exchanges and micronuclei (MN). The validation of biomarkers includes measurements of sensitivity and specificity of biomarkers and round robin tests to ensure reproducible protocols within different laboratories. The predictive value of biomarkers with respect to adverse health effect from the result of the measurement has been performed for the cytogenetic biomarkers showing a predictive value of high levels of CA and increased risk of cancer. The use of CA in future studies is, however, limited by the laborious and sensitive procedure of the test and lack of trained cytogeneticists. Less time consuming, but robust biomarkers, sensitive to environmental exposures are suggested. From the selection of developed biomarkers, the comet assay is highly sensitive to lifestyle exposures, often confounding the output, while MN in lymphocytes seem promising with respect to laboratory and health effect (cancer) validity. Also, new biomarkers exploiting the new 'omics' technologies are being developed. A number of ethical issues arise from the use of biomarkers with a predictive value aiming at respecting the autonomy of the study person in participation (only upon written informed consent and with obligations of withdrawal at any time), access to personal information (right to know and right not to know the study result) and securing proper data management (data protection to avoid misuse in employment, insurance, loaning and learning opportunities).

Polyethylene-glycol conjugated recombinant human acetylcholinesterase serves as an efficacious bioscavenger against soman intoxication.

Extensive pharmacokinetic studies in both mice and rhesus macaques, with biochemically well defined forms of native and recombinant AChEs from bovine, rhesus and human origin, allowed us to determine an hierarchical pattern by which post-translation-related factors and specific amino-acid epitopes govern the pharmacokinetic performance of the enzyme molecule. In parallel, we demonstrated that controlled conjugation of polyethylene-glycol (PEG) side-chains to lysine residues of rHuAChE also results in the generation of active enzyme with improved pharmacokinetic performance. Here, we show that equally efficient extension of circulatory residence can be achieved by specific conditions of PEGylation, regardless of the post-translation-modification state of the enzyme. The masking effect of PEGylation, which is responsible for extending circulatory lifetime, also contributes to the elimination of immunological responses following repeated administration of AChE. Finally, in vivo protection studies in mice allowed us to determine that the PEGylated AChE protects the animal from a high lethal dose (2.5 LD(50)) of soman. On a mole basis, both the recombinant AChE and its PEGylated form provide higher levels of protection against soman poisoning than the native serum-derived HuBChE. The findings that circulatory long-lived PEGylated AChE can confer superior protection to mice against OP-compound poisoning while exhibiting reduced immunogenicity, suggest that this chemically modified version of rHuAChE may serve as a highly effective bioscavenger for prophylactic treatment against OP-poisoning.

Effect of hyperprolinemia on acetylcholinesterase and butyrylcholinesterase activities in rat.

We observed here that acute proline (Pro) administration provoked a decrease (32%) of acetylcholinesterase (AChE) activity in cerebral cortex and an increase (22%) of butyrylcholinesterase (BuChE) activity in the serum of 29-day-old rats. In contrast, chronic administration of Pro did not alter AChE or BuChE activities. Furthermore, pretreatment of rats with vitamins E and C combined or alone, N(omega)-nitro-L-arginine methyl ester or melatonin prevented the reduction of AChE activity caused by acute Pro administration, suggesting the participation of oxidative stress in such effects.