RESUMO

In the present study, the sensitivity and concentration dependence of three functionally-defined components of cholinesterase activity (total: T-ChE; eserine-sensitive: Es-ChE; and eserine-resistant: Er-ChE) were quantified in the gill, digestive gland and adductor muscle of the tropical cup oyster Saccostrea sp., following acute (96h) aqueous exposure to commercial formulations of the organophosphate (OP) insecticide chlorpyrifos and the neonicotinoid (NN) imidacloprid (concentration range: 0.1-100mg/L), as well as to dissolved cadmium and copper (concentration range: 1-1000µg/L). Oysters (1.5-5.0cm shell length), field-collected from a boating marina in Santa Marta, Colombia (Caribbean Sea) were exposed in the laboratory to each substance at five concentrations. T-ChE, Es-ChE, and Er-ChE activity were quantified in the three tissues in pools of 5 individuals (3 replicates per concentration), before and after inhibition with the total cholinesterase inhibitor eserine (physostigmine, 100µM). Oysters exposed to chlorpyrifos, imidacloprid and Cd showed reduced T-ChE and Es-ChE activity in gills at highest exposure concentrations, with Es-ChE activity being inhibited proportionally more so than T-ChE, whereas Er-ChE activity showed no significant concentration-response. Digestive gland also showed diminished T-ChE, Es-ChE and Er-ChE activity for highest chlorpyrifos and Cd concentrations relative to controls, but an increase of T-ChE and Er-ChE activity at the highest imidacloprid concentration (100mg/L). For Cu, T-ChE, Es-ChE and Er-ChE activities in gills and digestive gland were elevated relative to controls in oysters exposed to Cu concentrations > 100µg/L. In adductor muscle, T-ChE, Es-ChE and Er-ChE activity showed no apparent pattern for any of the four xenobiotics and concentration levels tested. Although this study confirms acute (96h) concentration-dependent reduction of tissue T-ChE and Es-ChE activity in gills and digestive glands of Saccostrea sp. exposed to high concentrations of chlorpyrifos (100mg/L), significant changes in T-ChE, Es-ChE and Er-ChE were also caused by exposure to Cd and Cu at concentrations > 100µg/L and by exposure to imidacloprid (100mg/L), indicating that cholinesterase activity is not a specific biomarker of organophosphate exposure in this species, but, rather, a biomarker of diverse xenobiotic exposure.

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The incidence of facial trauma is high. This study has the primary objective of documenting and cataloging maxillofacial fractures in polytrauma patients. From a total of 1229 multiple trauma cases treated at the Emergency Room of the Santo Antonio Hospital - Oporto Hospital Center, Portugal, between August 2001 and December 2007, 251 patients had facial wounds and 209 had maxillofacial fractures. Aged ranged form 13 to 86 years. The applied selective method was based on the presence of facial wound with Abbreviated Injury Scale ≥1. Men had a higher incidence of maxillofacial fractures among multiple trauma patients (86.6%) and road traffic accidents were the primary cause of injuries (69.38%). Nasoorbitoethmoid complex was the most affected region (67.46%) followed by the maxilla (57.42%). The pattern and presentation of maxillofacial fractures had been studied in many parts of the world with varying results. Severe multiple trauma patients had different patterns of maxillofacial injuries. The number of maxillofacial trauma is on the rise worldwide as well as the incidence of associated sequelae. Maxillofacial fractures on multiple trauma patients were more frequent among males and in road traffic crashes. Knowing such data is elementary. The society should have a key role in the awareness of individuals and in prevention of road traffic accidents.

É alta a incidência de traumas na face. Este estudo teve por objetivo documentar e catalogar as fraturas maxilofaciais em pacientes com politraumatismos. De um total de 1229 casos de politraumatizados tratados na Sala de Emergência do Hospital de Santo António - Centro Hospitalar do Porto, Portugal, entre Agosto de 2001 e Dezembro de 2007, 251 pacientes tiveram ferimentos na face e 209 apresentaram fraturas maxilofaciais. As idades variaram de 13 a 86 anos. O método de seleção baseou-se na presença de ferimentos na face com Abreviated Injury Scale ≥1. Os homens apresentaram maior incidência de fraturas maxilofaciais (86,6%) entre os pacientes com múltiplos traumatismos na face e os acidentes de trânsito foram a causa principal dos traumatismos (69,38%). A região mais afetada foi o complexo naso-órbito-etmoidal (67,46%), seguido pela maxila (57,42%). O padrão e a apresentação das fraturas maxilofaciais tem sido estudado em muitas regiões do mundo com resultados variados. Pacientes com politraumatizados graves apresentaram padrões diferentes de traumatismos maxilofaciais. O número de traumatismos maxilofaciais tem aumentado à escala mundial, assim como a incidência das sequelas associadas. Entre os pacientes com traumatismos múltiplos, a maioria pertencia ao sexo masculino, assim como a causa mais frequente foram os acidentes automobilísticos. É elementar o conhecimento destes dados. A sociedade tem um papel primordial nos cuidados individuais e na prevenção dos acidentes de trânsito.

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Environmental chemicals may be involved in the etiology of breast cancers. Many studies have addressed the association between cancer in humans and agricultural pesticide exposure. Organophosphorous pesticides have been used extensively to control mosquito plagues. Parathion and malathion are organophosphorous pesticides extensively used to control a wide range of sucking and chewing pests of field crops, fruits, and vegetables. They have many structural similarities with naturally occurring compounds, and their primary target of action in insects is the nervous system; they inhibit the release of the enzyme acetylcholinesterase at the synaptic junction. Eserine, parathion, and malathion are cholinesterase inhibitors responsible for the hydrolysis of body choline esters, including acetylcholine at cholinergic synapses. Atropine, a parasympatholytic alkaloid, is used as an antidote to acetylcholinesterase inhibitors. The aim of this study was to examine whether pesticides were able to induce malignant transformation of the rat mammary gland and to determine whether alterations induced by these substances increase the cholinergic activation influencing such transformation. These results showed that eserine, parathion, and malathion increased cell proliferation of terminal end buds of the 44-day-old mammary gland of rats, followed by formation of 8.6, 14.3, and 24.3% of mammary carcinomas, respectively, after about 28 months. At the same time, acetylcholinesterase activity decreased in the serum of these animals from 9.78 +/- 0.78 U/mL in the control animals to 3.05 +/- 0.06 U/mL; 2.57 +/- 0.15 U/mL; and 3.88 +/- 0.44 U/mL in the eserine-, parathion-, and malathion-treated groups, respectively. However, atropine alone induced a significant (p < 0.05) decrease in the acetylcholinesterase activity from the control value of 9.78 +/- 0.78 to 4.38 +/- 0.10 for atropine alone, to 1.32 +/- 0.06 for atropine in combination with eserine, and 2.39 +/- 0.29 for atropine with malathion, and there was no mammary tumor formation. These results indicate that organophosphorous pesticides induce changes in the epithelium of mammary gland influencing the process of carcinogenesis, and such alterations occur at the level of nervous system by increasing the cholinergic stimulation.

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The effects of toxin Ts-gamma and tityustoxin purified from Tityus serrulatus scorpion venom were investigated on isolated rat atria. Rat atria were placed in an organ bath containing Krebs-Ringer solution, 30 degrees C, pH 7.4, and bubbled with a gas mixture of 95% O2 and 5% CO2. The atrial rate and contractile force were simultaneously recorded. Addition of toxin Ts-gamma to the bath (0.14 microM) evoked an initial reduction of both atrial rate and contractile force, followed by a small increase in force and a decrease in rate, and finally a long reduction of rate and force. Addition of an identical dose of Ts-gamma 30 or 60 min later did not evoke any effect. Addition of tityustoxin to the bath (0.14 microM) induced an increase of atrial rate and force. Addition of an identical dose of tityustoxin 30 min later evoked similar effects. The negative chronotropic and inotropic effects induced by Ts-gamma were abolished by tetrodotoxin (TTX, 1 microM) or atropine (1.5 microM), whereas the positive effects observed in the presence of atropine were prevented by TTX (1 microM) or alprenolol (10 microM). The negative chronotropic effect of 0.14 microM tityustoxin was only observed in the presence of physostigmine (0.3 microM). This negative effect was abolished by TTX (1 microM) or atropine (1.5 microM). The positive inotropic effect of tityustoxin was decreased by TTX (1 microM and 10 microM), but was totally prevented by guanethidine (10 microM) or alprenolol (10 microM).(ABSTRACT TRUNCATED AT 250 WORDS)

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Ketamine is an anaesthetic interacting with several neurotransmitters. Among others, ketamine exerts some cholinergic actions (ACh). This paper presents the results of studying the interaction of ketamine with ACh in two animal species. Atropine slightly increased the time of immobility produced by ketamine injections in rats. Meanwhile, neostigmine slightly decreased such immobility. Ketamine resulted similar in behavioral actions and shared some electroencephalographic (EEG) actions of scopolamine in cats. The most striking interaction consisted on an antagonism of ketamine on the action of anticholinesterase agents. In both species, ketamine blocked the EEG and the behavioral toxic effects of neostigmine and physostigmine. Notwithstanding, the anticholinesterase agents were unable in reducing the actions of ketamine. This partial cholinergic agonist action of ketamine support certain but limited use of the anesthetic against insecticidal anticholinesterase poisoning.

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The aim of the present study was to compare the reliability of LD50 determination using the traditional Litchfield and Wilcoxon method with that obtained by four alternative tests requiring smaller numbers of animals, for the purpose of classifying chemicals according to their acute toxicity. Acute lethal dose determinations were carried out in mice for oral and intraperitoneal administration of hexachlorophene, lidocaine, methanol, phenobarbital and physostigmine. The Molinengo method proved not to be as reliable as suggested by its author. Determination of LD50 using the Thompson and Weil method or, alternatively, the maximal non-lethal dose and the approximate lethal dose permitted the classification of the chemicals in essentially the same order. The approximate lethal dose method, in particular, seems to be a very suitable alternative method to the classical LD50 test since it requires only about 6 animals, provides enough information to order chemicals according to their toxicities, and provides useful information for planning subsequent repeated-dose studies.

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RESUMO

The aim of the prsent study was to compare the realibility of LD50 determination using the traditional Litchfield and Wilcoxon method with that obtained by forur alternative tests requiring smaller numbers of animals, for the purpose of classifyng chemicals according to their acute toxicity. Acute lethal dose determinations were carried out in mice for oral and intraperitoneal administration of hexachlorophene, lidocaine, methanol, phenobarbital and physostigmine. The Molinengo method proved not to be as reliable as suggested by its author. Determination of LD50 using the Thompson and Weil method or, alternatively, the maximal non-lethal dose and the approximate lethal dose permitted the classification of the chemicals in essentially the same order. The approximate lethal dose method, in particular, seems to be a very suitable alternative method to the classical LD50 test since it requires only about 6 animals, provides enough information to order chemicals according to their toxicities, and provides useful information for planning subsequent repeated-dose studies

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