Changes In Cholinesterase Activity Research Articles

Occurrence of butyrylcholinesterase polymorphisms in patients undergoing surgery in Slovakia.

Post-operative residual curarization is a persisting problem, characterized by muscle fatigue, exhaustion or paresis, caused by the use of neuromuscular blocking agents with prolonged postoperative effect. Genetically, determined changes in cholinesterase activity can be a major reason for persistent muscle blockade after administration of muscle relaxants. Regarding the subsistence of polymorphisms in the plasma cholinesterase gene causing change in enzyme activity and metabolism of applied drugs, we investigated the frequency of two polymorphisms known to reduce its activity significantly in patients undergoing surgery. Primary results show a relatively high occurrence of plasma cholinesterase K risk allele (18.75%). Characterization of the lacking information about genetic background of changes in plasma cholinesterase activity within Slovakia may allow for easier decision-making in clinical practice when selecting alternative neuromuscular blocking and also reversal agents.

Pesticide-induced changes in cholinesterase activity and chronic kidney disease of unknown etiology among farmers in Nakhon Ratchasima, Thailand

Chronic kidney disease of unknown etiology (CKDu) has emerged agricultural population. This study aimed to obtain a prevalence of cholinesterase activity and CKDu, and evaluate factors associated with organophosphate (OP) and carbamate (CA) poisoning and CKDu among farmers in Nakhon Ratchasima province, Thailand. A cross-sectional study was conducted among 58 farmers, with data collected using a structured questionnaire. Blood and urine samples were collected for analysis of erythrocyte acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), serum creatinine (SCr), and urinary creatinine (UCr). Farmers who had CKD without diabetes, hypertension, proteinurea, and other traditional causes were classified as CKDu. The average age (± SD) was 49.22(± 6.87) years. The prevalence of abnormal AChE and BuChE activity levels were 55.17% and 46.55%, respectively. In kidney function, the prevalence of abnormal UCr was 17.24% and CKDu was 24.14%. In adjusted model, the type of pesticide sprayer and personal protective equipment used were significantly associated with CKDu (bivariate analysis, p < 0.05). Using multivariate analysis, OP and CA poisoning were significantly associated with a 4.703-fold higher risk of CKDu (95% CI = 1.020-21.686). Farmers who applied OP and CA pesticides had decreased kidney function. These findings might be beneficial in reducing the adverse effects pesticide exposure and CKDu prevention.

Effect of diphenhydramine on the changes in cholinesterase activity and intestinal motility induced by imidocarb in chicks

Effect of diphenhydramine on the changes in cholinesterase activity and intestinal motility induced by imidocarb in chicks

Cholinesterase Activities and Oxidative Stress in Cattle Experimentally Exposed to Nitrate/Nitrite in Cultivated Pasture with Different Fertilization Schemes

Background: Nitrate and nitrite poisoning is associated with pasture intake that has high nitrate levels and leads to acute methemoglobinemia. Pasture may accumulate nitrate under certain conditions, such as excessively fertilized soil or en­vironmental conditions that enhance the N absorption (rain preceded by a period of drought). After ingestion of plants, this substrate reaches the rumen and, in physiological conditions, is reduced to nitrite and afterward to ammonia. The aim of this study was to evaluate changes in cholinesterase activities and oxidative stress caused by subclinical poisoning for nitrate and nitrite in cattle fed with Pennisetum glaucum in three different fertilization schemes. Materials, Methods &amp; Results: In order to perform the experimental poisoning, the pasture was cultivated in three dif­ferent paddocks: with nitrogen topdressing (urea; group 1), organic fertilizer (group 2) or without fertilizer (group 3; control). Nitrate accumulation in forage was evaluated by the diphenylamine test. After food fasting of 12 h, nine bovine were randomly allocated to one of the experimental groups and fed with fresh forage (ad libitum) from respective pad­dock. In different time points from beginning of pasture intake (0, 2, 4, 6 and 9 h) heart rate and respiratory frequency were assessed, as well as mucous membrane color and behavioral changes. Blood samples from jugular vein into vials with and without anticoagulant were collected. From blood samples, serum nitrite levels, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzyme activity were evaluated, as well as oxidative stress through the following param­eters: levels of nitrate/nitrite (NOx), thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS), beyond the antioxidant system by enzyme activity measurement of catalase (CAT) and superoxide dismutase (SOD). The diphenylamine test was positive to group 1 and 2, so that the pasture presented 3.16 mg/kg, 2.98 mg/kg and 1.67 mg/kg of nitrate for group 1, 2 and 3, respectively. In addition, cows from group 1 demonstrated increased (P &lt; 0.05) nitrite levels in serum, compared to other groups, and greater heart rate after 9 h (P &lt; 0.05). The AChE and BChE activity in group 1 showed significant increase (P &lt; 0.05) at 4 and 6 h (AChE), and 4 and 9 h (BChE) compared to group 3. Also, NOx levels were lower at 6 and 9 h (P &lt; 0.05) and at 9 h (P &lt; 0.05) for animals of group 1 and 2, respectively, when compared to group 3. Furthermore, in the group 1 levels of ROS and TBARS were significantly higher (P &lt; 0.05) after 2 and 4 h, and 6 and 9 h compared to other groups, respectively. The CAT activity increased significantly (P &lt; 0.05) with 2 and 4 h of the experiment, but on the other hand, decreased at 6 and 9 h in group 1. Nevertheless, the animals from group 2 presented only a significant reduction in this enzyme activity at 9 h. Furthermore, SOD activity was reduced in animals of groups 1 (P &lt; 0.05) at 4, 6 and 9 h, compared to other groups. Discussion: It was concluded that the nitrate and nitrite poisoning by pasture intake cultivated and fertilized with urea leads to increased levels of serum nitrite, as well as the cholinesterase activity and causes oxidative stress in cattle. It is conjectured that the cholinesterase activity and oxidative stress may assist in understanding the pathophysiology of changes caused by poisoning.Keywords: plant toxicology, poisoning, methemoglobin, cholinergic system, oxidative stress.

Cholinesterase Activities and Oxidative Stress in Cattle Experimentally Exposed to Nitrate/Nitrite in Cultivated Pasture with Different Fertilization Schemes

Background: Nitrate and nitrite poisoning is associated with pasture intake that has high nitrate levels and leads to acute methemoglobinemia. Pasture may accumulate nitrate under certain conditions, such as excessively fertilized soil or environmental conditions that enhance the N absorption (rain preceded by a period of drought). After ingestion of plants, this substrate reaches the rumen and, in physiological conditions, is reduced to nitrite and afterward to ammonia. The aim of this study was to evaluate changes in cholinesterase activities and oxidative stress caused by subclinical poisoning for nitrate and nitrite in cattle fed with Pennisetum glaucum in three different fertilization schemes.Materials, Methods &amp; Results: In order to perform the experimental poisoning, the pasture was cultivated in three different paddocks: with nitrogen topdressing (urea; group 1), organic fertilizer (group 2) or without fertilizer (group 3; control). Nitrate accumulation in forage was evaluated by the diphenylamine test. After food fasting of 12 h, nine bovine were randomly allocated to one of the experimental groups and fed with fresh forage (ad libitum) from respective paddock. In different time points from beginning of pasture intake (0, 2, 4, 6 and 9 h) heart rate and respiratory frequency were assessed, as well as mucous membrane color and behavioral changes. Blood samples from jugular vein into vials with and without anticoagulant were collected. From blood samples, serum nitrite levels, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzyme activity were evaluated, as well as oxidative stress through the following parameters: levels of nitrate/nitrite (NOx ), thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS), beyond the antioxidant system by enzyme activity measurement of catalase (CAT) and superoxide dismutase (SOD). The diphenylamine test was positive to group 1 and 2, so that the pasture presented 3.16 mg/kg, 2.98 mg/kg and 1.67 mg/kg of nitrate for group 1, 2 and 3, respectively. In addition, cows from group 1 demonstrated increased (P &lt; 0.05) nitrite levels in serum, compared to other groups, and greater heart rate after 9 h (P &lt; 0.05). The AChE and BChE activity in group 1 showed significant increase (P &lt; 0.05) at 4 and 6 h (AChE), and 4 and 9 h (BChE) compared to group 3. Also, NOx levels were lower at 6 and 9 h (P &lt; 0.05) and at 9 h (P &lt; 0.05) for animals of group 1 and 2, respectively, when compared to group 3. Furthermore, in the group 1 levels of ROS and TBARS were significantly higher (P &lt; 0.05) after 2 and 4 h, and 6 and 9 h compared to other groups, respectively. The CAT activity increased significantly (P &lt; 0.05) with 2 and 4 h of the experiment, but on the other hand, decreased at 6 and 9 h in group 1. Nevertheless, the animals from group 2 presented only a significant reduction in this enzyme activity at 9 h. Furthermore, SOD activity was reduced in animals of groups 1 (P &lt; 0.05) at 4, 6 and 9 h, compared to other groups.Discussion: It was concluded that the nitrate and nitrite poisoning by pasture intake cultivated and fertilized with urea leads to increased levels of serum nitrite, as well as the cholinesterase activity and causes oxidative stress in cattle. It is conjectured that the cholinesterase activity and oxidative stress may assist in understanding the pathophysiology of changes caused by poisoning.

Sarin Exposures in A Cohort of British Military Participants in Human Experimental Research at Porton Down 1945-1987.

The effects of exposure to chemical warfare agents in humans are topical. Porton Down is the UK's centre for research on chemical warfare where, since WWI, a programme of experiments involving ~30000 participants drawn from the UK armed services has been undertaken. Our aim is to report on exposures to nerve agents, particularly sarin, using detailed exposure data not explored in a previous analysis. In this paper, we have used existing data on exposures to servicemen who attended the human volunteer programme at Porton Down to examine exposures to nerve agents in general and to sarin in particular. Six principal nerve agents were tested on humans between 1945 and 1987. Of all 4299 nerve agent tests recorded, 3511 (82%) were with sarin, most commonly in an exposure chamber, with inhalation being the commonest exposure route (85%). Biological response to sarin exposure was expressed as percentage change in cholinesterase activity and, less commonly, change in pupil size. For red blood cell cholinesterase, median inhibition for inhalation tests was 41% (interquartile range 28-51%), with a maximum of 87%. For dermal exposures the maximum inhibition recorded was 99%. There was a clear association between increasing exposure to sarin and depression of cholinesterase activity but the strength and direction of the association varied by exposure route and the presence of chemical or physical protection. Pupil size decreased with increased exposure but this relationship was less clear when modifiers, such as atropine drops, were present. These results, drawn from high quality experimental data, offer a unique insight into the effects of these chemical agents on humans.

Oxidative stress markers in fish (Astyanax sp. and Danio rerio) exposed to urban and agricultural effluents in the Brazilian Pampa biome.

Aquatic ecosystems are under constant risk due to industrial, agricultural, and urban activities, compromising water quality and preservation of aquatic biota. The assessment of toxicological impacts caused by pollutants to aquatic environment using biomarker measurements in fish can provide reliable data to estimate sublethal effects posed by chemicals in contaminated areas. In this study, fish (Astyanax sp. and Danio rerio) exposed to agricultural and urban effluents at the Vacacaí River, Brazil, were tested for potential signs of aquatic contamination. This river comprehends one of the main watercourses of the Brazilian Pampa, a biome with a large biodiversity that has been neglected in terms of environmental and social-economic development. Sites S1 and S2 were chosen by their proximity to crops and wastewater discharge points, while reference site was located upstream of S1 and S2, in an apparently non-degraded area. Fish muscle and brain tissues were processed for determination of acetylcholinesterase as well as oxidative stress-related biomarkers. The results showed signs of environmental contamination, hallmarked by significant changes in cholinesterase activity, expression of metallothionein, antioxidant enzymes, glutathione levels, and activation of antioxidant/cell stress response signaling pathways in fish exposed to contaminated sites when compared to reference. Based on these results, it is evidenced that urban and agricultural activities are posing risk to the environmental quality of water resources at the studied area. It is also demonstrated that cell stress biomarkers may serve as important tools for biomonitoring and development of risk assessment protocols in the Pampa biome.

English

To investigate the incidence of pesticide poisoning using serum cholinesterase activity patterns in a horticultural farm, 616 people comprising of 496 pesticide handlers (test group) and a control group of 120 persons participated in the study. A semi-structured questionnaire was used to obtain demographic information, while the activities of serum cholinesterase, serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, alkaline phosphatase and bilirubin were estimated using standard commercial kits and absorbance measured using kinetic colorimetric tests. All the pesticide handlers (100%) were males, with majority (80.3%) aged 20 to 35 years old. Of the test population, 6% had significant cholinesterase enzyme depressions with no symptoms of exposure recorded. Significant difference (p 0.05) between the test and control groups based on years of handling pesticides. Use of pesticides in successive spray seasons significantly inhibited cholinesterase activity among the spray team, supervisors and harvesters (p<0.05). Higher cholinesterase activity was observed in the 31 to 40 age group with significant changes in cholinesterase activity (p<0.05) observed among those aged below 40 years. The study indicates that cholinesterase activity can be used effectively as an indicator of exposure to pesticides. Key words: Cholinesterase activity, pesticide handlers, Naivasha, monitoring program.

Developmental abnormalities and changes in cholinesterase activity in sea urchin embryos and larvae from sperm exposed to engineered nanoparticles

The objective of this study is to examine the toxicity of engineered nanoparticles (NPs) that are dispersed in sea water by using an in vivo model. Because many products of nanotechnology contain NPs and are commonly used and well-established in the market, the accidental release of NPs into the air and water is quite possible. Indeed, at the end of their life cycle, some NPs are inevitably released into waste water and can reach marine ecosystem and affect the organisms there. Although there are few data on the presence of NPs in the marine environment, our awareness of their potential impact on environmental and organismal health is growing. Shallow-water benthonic organisms such as sea urchins provide planktonic larvae as a trophic base for finfish juveniles and are exposed to water from estuaries and precipitation. Such organisms can therefore be directly affected by NPs that are dispersed into those media.We evaluated the effects of exposure to different concentrations of nanosilver, titanium oxide and cobalt NPs on the sperm of the sea urchin Paracentrotus lividus by analyzing the functionality and the morphology and biochemistry of the first developmental stages of the sea urchin.Sperm were exposed to sea water containing suspensions of NPs ranging from 0.0001mg/L to 1mg/L. Fertilization ability was not affected, but developmental anomalies were identified in embryos from the gastrula to pluteus stages, including morphological alterations of the skeletal rods. In addition, the enzymatic activity (cholinesterase, ChE) of the larvae was measured. Acetylcholinesterase (AChE) and propionylcholinesterase activity (PrChE) was affected in all of the exposed samples. The results did not vary consistently with the concentration of NP, but controls were significantly different from exposed samples. Exposure of sea urchin to these NPs may cause neurotoxic damage, and the altered ChE activity may be involved in skeletogenic aberrations. In conclusion, the sea urchin represents a suitable and sensitive model for testing the toxicity and effects of engineered NPs that are dispersed in sea water.

Effect of induced epilepsy on some biochemical parameters in female rats

The activity of cholinesterase and some biochemical parameters of blood such as glucose, cholesterol and phospholipids were estimated in 52 epilepsy induced females of Wister albino rats. Animals of this experiment were divided into two groups, group (I) regarded as control and group (II) administrated subcutaneously by pentylenetetrazole 100mg/kg and divided in to three sub-groups according to the time of samples collection 3 hrs, 24 hrs and 1 week. The results revealed that epilepsy induction caused a significant inhibition of serum cholinesterase activity 3 hrs after induction while in the brain, the activity of cholinesterase was significantly increased after 24 hrs Serum glucose level was significantly elevated after 3 hrs and 24 hrs of induction, total cholesterol and phospholipids were not changed. From the results obtained in this study, it can be concluded that epilepsy caused significant changes in cholinesterase activity in brain and serum in addition to the glucose level in the serum.

DERMAL EXPOSURES TO SARIN IN MILITARY VETERANS AT PORTON DOWN

Background The modification of dermal exposures by clothing, which may either protect from exposure or increase its effect, is of considerable interest. Here, we describe early analyses of the effects of dermal exposures to the nerve agent sarin, using data drawn from our previous cohort study of military veterans of chemical tests at Porton Down between, 1939-1989. Methods Data on exposures were abstracted from the Porton Down historical archive. For each nerve agent test we abstracted data on date and type of test, the principal chemical(s) used and exposure intensity, duration and route. We also noted the presence of exposure modifiers. Maximum percentage change in the following cholinesterase (ChE) measures were abstracted or calculated: unspecified, whole blood, plasma and/or red blood cell (RBC) ChE. Results 3597 veterans were recorded as involved in 4299 tests with nerve agents, 1945-1987. The most tested nerve agent was sarin: 2980 veterans were involved in 3511 tests. 288 sarin exposures were dermal (9.6%) and most of those were modified physically, eg by clothing (188; 65%). Dermal sarin tests took place 1951 - 1953. Quantity of exposure to dermal sarin was measured for 273 tests and ranged from 0.13 to 300 mg. Applied exposures were higher in tests with modification (IQR 200-300 mg with modification and 0.28-8 mg without). Change in ChE activity was available for 279 dermal sarin tests (97%). The median change was -22% (IQR -10 to - 37%, range +12.5 to -99%). The median without modification was -4.5% (IQR 0 to -13%) and -31% (IQR -19 to -46%) with modification. Conclusions The quantity of dermal exposure to sarin influenced effect. However, modifier use may be confounded by exposure so further investigation of the relationships between exposure, effect, and modification will be carried out.

Differential cholinesterase inhibition in the rat brain regions by dichlorvos and protective effect of Decalepis hamiltonii roots

Dichlorvos (DDVP) causes neurotoxicity primarily by inhibiting cholinesterase (ChE) which is the characteristic feature of organophosphate pesticides. In this study, we found for the first time that DDVP shows differential inhibition of ChE (acetylcholinesterase+butyrylcholinesterase) in various rat brain regions. A single dose of DDVP (1/3 LD50) after 16h of treatment elicited ChE inhibition in the brain regions which was highest in striatum and lowest in cerebellum. The inhibition of ChE by DDVP has been shown to be accompanied with induction of oxidative stress. Further, we investigated the protective potential of the aqueous extract of the roots of Decalepis hamiltonii (DHA), having potent antioxidant constituents, against DDVP-induced ChE inhibition in various rat brain regions. Pretreatment of rats with multiple doses of DHA, 50 and 100mg/kg b.w., for 7 consecutive days did not produce any significant change in ChE activity. Pretreatment of rats with DHA, at high dose, significantly protected against DDVP-induced ChE inhibition in all the brain regions except cerebellum. Pretreatment of rats with DHA, at low dose, showed significant protection in striatum, cortex, and pons against DDVP-induced ChE inhibition. The protective activity of DHA can be attributed to the characterized potent antioxidant constituents which could have an important role in preventing ChE inhibition by inducing the DDVP detoxifying enzymes. We strongly believe that these antioxidant constituents are prospective novel nutriceuticals.

Histopathology and cholinergic assessment of Pterocarya fraxinifolia on chicken embryo.

There are no reports of toxicological studies of Pterocarya fraxinifolia. The leaves are used for fishing, which also an anesthetic agent. Currently, many drugs utilized in anesthesia practice are modified cholinergic transmission and acetylcholine esterase inhibitors; these are parts of anaesthetic pharmacy. Therefore, cholinergic assessment was surveyed in chicken embryo, which Pterocarya fraxinifolia extractes were injected in 0.1, 1 and 10 mg concentration at day 4 of incubation. Serum and brain cholinesterase were analyzed on day 20 of incubation. The signs were not due to the changes of cholinesterase activity. In histopathology examination, massive necrosis was observed in the spinal cord. Other tissues such as heart, kidneys, skeletal bones and muscles, trachea and lungs, digestive system and endocrine glands were completely developed. This data suggests that the spinal cord is a target organ of the bioactive component of this plant.

Variation of cholinesterase-based biosensor sensitivity to inhibition by organophosphate due to ionizing radiation.

A cholinesterase based biosensor was constructed in order to assess the effects of ionizing radiation on exposed AChE. Although the primary objective of the experiment was to investigate the effect of ionizing radiation on the activity of the biosensor, no changes in cholinesterase activity were observed. Current provided by oxidation of thiocholine previously created from acetylthiocholine by enzyme catalyzed reaction was in a range 395–455 nA. No significant influence of radiation on AChE activity was found, despite the current variation. However, a surprising phenomenon was observed when a model organophosphate paraoxon was assayed. Irradiated biosensors seem to be more susceptible to the inhibitory effects of paraoxon. Control biosensors provided a 94 ± 5 nA current after exposure to 1 ppm paraoxon. The biosensors irradiated by a 5 kGy radiation dose and exposed to paraoxon provided a current of 49 ± 6 nA. Irradiation by doses ranging from 5 mGy to 100 kGy were investigated and the mentioned effect was confirmed at doses above 50 Gy. After the first promising experiments, biosensors irradiated by 5 kGy were used for calibration on paraoxon and compared with the control biosensors. Limits of detection 2.5 and 3.8 ppb were achieved for irradiated and non-irradiated biosensors respectively. The overall impact of this effect is discussed.

In vitro exposure of heavy metals on nucleotidase and cholinesterase activities from the digestive gland of Helix aspersa

Zinc, copper and cadmium are important environmental contaminants and differences in purinergic and cholinergic systems of invertebrates have been described when compared to characteristics of these signaling systems in vertebrates. Here we evaluate the effect in vitro of these metals on the ATPase, 5′-nucleotidase and cholinesterase (ChE) activities in the digestive gland of Helix aspersa. Zinc (500 and 1000 μM) promoted a significant decrease in 5′-nucleotidase activity. However, it did not induce changes in ATP hydrolysis. Copper (25 and 50 μM), inhibited significantly ATPase activity, but did not alter 5′-nucleotidase when compared to control (no metal added). In relation to effects of cadmium, an inhibitory effect on ATP hydrolysis has been observed at concentrations of 100, 500 and 1000 μM and a similar decrease of AMP hydrolysis was observed at 500 and 1000 μM. However, there were no significant changes in ChE activity from homogenates of the digestive gland of H. aspersa for all metals tested. This study demonstrated that zinc, cadmium and copper affect ATPase and 5′-nucleotidase in digestive gland, but not ChE, suggesting that the purinergic system may be a target related to toxicity induced by these metals and a possible indicator of biological impact of exposure to these contaminants.

Age-dependent changes in plasma and brain cholinesterase activities of house wrens and European starlings.

We determined age-dependent changes in plasma and brain cholinesterase (ChE) activity for two species of passerines: house wren (Troglodytes aedon) and European starling (Sturnus vulgaris, starling). In plasma from nestlings of both species, total ChE activity increased with age, acetycholinesterase (AChE, EC 3.1.1.7) activity declined rapidly immediately after hatching, and butyrylcholinesterase (BChE, EC 3.1.1.8) activity increased steadily. For both species, total ChE and BChE activities and the BChE:AChE ratio in plasma were significantly greater in adults than nestlings suggesting trends observed in nestlings continue post fledging. In older nestlings and adults, AChE activity in plasma was significantly greater and BChE:AChE ratio less in house wrens than starlings. For house wrens as compared with starlings, ChE activity in brain increased at a significantly greater rate with age in nestlings and was significantly greater in adults. However, ChE activity in brain was similar at fledging for both species suggesting that the increase in ChE in brain is more directly related to ontogeny than chronologic age in nestlings of passerines. For both species, ChE activity increased significantly with brain weight of nestlings but not adults. House wrens hold similar patterns of age-dependent change in ChE activity in common with starlings but also exhibit differences in AChE activity in plasma that should be considered as a factor potentially affecting their relative toxicologic response to ChE inhibitors.

Neither forced running nor forced swimming affect acute pyridostigmine toxicity or brain-regional cholinesterase inhibition in rats

Stress-induced change in the distribution of the drug pyridostigmine (PYR) has been proposed as a contributing factor to unexplained illnesses in Persian Gulf War veterans. We evaluated the effects of two stress models, forced running and forced swimming, on acute PYR (30 mg/kg, p.o.) toxicity and cholinesterase (ChE) inhibition in the blood and selected brain regions of young adult male Sprague–Dawley rats (6 weeks of age). Plasma corticosterone levels were measured at 0, 1 and 3 h after termination of forced swimming or forced running to confirm the induction of stress. PYR was given either immediately before stress (15 min swimming; 20 min running) or immediately after stress (15 min swimming; 90 min running) and cholinergic toxicity and ChE inhibition were evaluated at 1, 2 or 4 h after PYR exposure. Additionally, rats were subjected to either swimming (15 min) or running (90 min) stress, anesthetized, injected with horseradish peroxidase (HRP, 100 mg/kg, transcardial) and brain-regional HRP activity measured as an indicator of altered blood–brain barrier integrity. Both forced swimming and forced running resulted in significant elevations of plasma corticosterone levels. PYR caused cholinergic toxicity at all time-points evaluated. Swimming and running stress had little influence on expression of PYR-induced toxicity, however. Blood ChE activity was generally inhibited 77–91% at 1–4 h after PYR, but rats pretreated with PYR prior to forced swimming showed lesser inhibition (64%) 1 h after dosing, possibly because of swimming-induced hypothermia and delayed absorption of the drug. Minimal changes in ChE activity were noted in frontal cortex, cerebellum and hippocampus following PYR exposure (maximal inhibition 28%), and neither swimming nor running stress affected the degree of inhibition. Neither stress model increased HRP accumulation in any brain region. The results suggest that stress associated with forced running or forced swimming has little effect on acute PYR toxicity, entry of PYR into the brain or PYR-induced brain-regional ChE inhibition.

Changes in Cholinesterase Activity, Nerve Conduction Velocity, and Clinical Signs and Symptoms in Termite Control Operators Exposed to Chlorpyrifos

Changes in Cholinesterase Activity, Nerve Conduction Velocity, and Clinical Signs and Symptoms in Termite Control Operators Exposed to Chlorpyrifos: Masahiro Gotoh, etal. Asahi Rosai Hospital—We have surveyed periodical medical examinations for pest and termite control operators (n=64) exposed to chlorpyrifos and other organophosphate pesticides. Distribution of serum butyrylcholinesterase (BuChE) activities of all workers ranged 0.01‐1.18 (ApH). Serum BuChE activities in 6 workers in one termite control company were severely depressed and ranged from 0.01 to 0.21 ΔpH. Erythrocyte acetylcholinesterase (AChE) activities in 3 workers were lower than the normal range. Erythrocyte AChE activities and serum BuChE acitivities in chlorpyrifos sprayers were significantly correlated (r=0.720). In other clinical signs, blood urine nitrogen (BUN) in 4 workers and white blood cell (WBC) counts in 4 workers were abnormal. Sensory nerve conduction velocities in the sural nerve of all 6 workers were significantly reduced to 18.8‐26.6 m/s in the left leg and 19.2‐27.2 m/s in the right leg. In the results of ophthalmic examinations, accommodation time (both eyes) in 4 workers extended over the normal range and electroretinography (ERG) in 2 workers showed abnormal ERG including disappearance of oscillatory potential. Chlorpyrifos residue in blood in 4 operators whose serum BuChE activities ranged from 0.01 to 0.03 ApH were detected in the range 2‐8 ng/m 1. They had sprayed chlorpyrifos daily for 5 d before every blood sampling. It is suggested that serum BuChE activity and sensory nerve conduction velocity are sensitive indicators to evaluate the effects of chlorpyrifos exposure, and may be used effectively to monitor exposure and the effects of chlorpyrifos on health.

Environmental Illness: Fatigue and Cholinesterase Activity in Patients Reporting Hypersensitivity to Electricity

The lack of a pathophysiological marker hinders studies on environmental illnesses of unknown origin. Hence, research focused on the identification of such a marker is a priority. This study investigated the nature and a possible etiology of fatigue in hypersensitivity to electricity (the most commonly reported environmental illness in Sweden). The aim was to test the hypothesis that perceived fatigue was due to alterations in cholinesterase activity. The study group consisted of 14 people who reported a hypersensitivity to electricity, including disabling fatigue. We assessed cholinesterase activity three times: twice based on current symptoms reported by the subjects (severe fatigue attributed to electromagnetic fields and absence of this symptom) and once at a randomly selected time. No significant reduction in acetylcholinesterase was identified in any subject. Examined on a group level, no significant reduction in activity was identified at the time of severe fatigue, and no correlation between reported degree of fatigue and cholinesterase activity was observed. Fatigue attributed to electromagnetic fields was nonphysical and showed a significant correlation to difficulties in concentrating. The results do not support the hypothesis that a change in cholinesterase activity mediates fatigue in people reporting hypersensitivity to electricity.

クロルピリホスに曝露された白蟻防除作業者におけるコリンエステラーゼ活性, 神経伝導速度, 臨床徴候および症状の変化

クロルピリホスに曝露された白蟻防除作業者におけるコリンエステラーゼ活性, 神経伝導速度, 臨床徴候および症状の変化