Intraindividual stability of human erythrocyte cholinesterase activity

BACKGROUND: Erythrocyte cholinesterase (RBC-ChE) activities serve as useful and sensitive biomarkers to monitor exposure to cholinesterase-inhibiting substances, such as chemical warfare nerve agents and pesticides. Although the interindividual variation of RBC-ChE is well characterized, the magnitude of intraindividual variation for RBC-ChE remains controversial. An accurate measure of intraindividual variation is critical for establishing the appropriate frequency of RBC-ChE testing. METHODS: We retrospectively tracked the intraindividual variation of RBC-ChE activities among 46 male nerve agent workers from a single US Army depot that participated in a medical surveillance program requiring periodic RBC-ChE monitoring. All RBC-ChE analysis was performed by the same medical laboratory technician by the delta pH method. RESULTS: A mean of 38 and a median of 37 RBC-ChE measurements were available for each worker. The mean duration of employment for these workers was 20 years (median, 21 years). The mean CV for RBC-ChE in this set of 46 workers was 3.9%. Linear regression analysis of the data for each worker resulted in a mean slope of 0.0010 delta pH units/h per year. CONCLUSIONS: RBC-ChE activities increased in each person by a mean of 0.01 delta pH units/h every 10 years, which is a negligible rate. These findings highlight the stability of RBC-ChE activities over time in a given individual and may have important policy implications regarding the appropriate frequency of RBC-ChE testing.     

Immunoreactive plasma cholinesterase (EC 3.1.1.8) substance concentration, compared with cholinesterase activity concentration and albumin: inter- and intra-individual variations in a healthy population group

Substance concentrations of plasma cholinesterase (EC 3.1.1.8) were measured in 94 healthy individuals without occupational exposure to known inhibitors (six samples from each individual). Immunoreactive cholinesterase substance concentrations showed an inter-individual variation corresponding to CVtotal = 22% (mean: 5.01 mg/l, SD: 1.11 mg/l). Intra-individual variations of immunoreactive cholinesterase substance concentration were correlated (r = 0.36) to intra-individual variation of albumin. Estimated by a repeated-measures analysis of variance, the observed intra-individual variation of cholinesterase substance concentration corresponded to CV = 8.8% (SD: 0.44 mg/l), which together with a CVerror = 6% (within and between runs), implies a biological intra-individual variation of cholinesterase substance concentration corresponding to CVintra = 6.4%. Specific catalytic activity (kU/mg immunoreactive cholinesterase) was influenced by the ChE-1 phenotype (phenotype U: 1.58 kU/mg, phenotype UA: 1.22 kU/mg), but not by body weight, height, age, and sex. Observed intra-individual variation of specific catalytic activity corresponded to 6.4% (SD: 0.10 kU/mg), which together with an estimated CVerror = 6.2% implies the biological intra-individual variations of specific catalytic cholinesterase activity to be insignificant. The insignificant CVintra makes specific catalytic cholinesterase activity a rational quantity for evaluation of unexpected fluctuations of cholinesterase activity concentrations.     

Mechanized assay of serum cholinesterase by specific colorimetric detection of released acid.

An automated assay method has been developed for the measurement of serum cholinesterase activity. The samples were prepared by an automated liquid handling unit and incubated for 9.7 min at 30 degrees C, followed by automatic injection into a colorimetric flow injection determination system for acetic acid liberated from acetylcholine by cholinesterase catalytic activity. The coloration reaction employed is based upon the formation of 2-nitrophenylhydrazide utilizing a water-soluble carbodiimide and has a high selectivity for carboxylic acids. The coefficients of variation of the proposed method were 2.4% for within-run analysis (n = 14) and 2.6% for between-run analysis (n = 6). Sera of 55 hospitalized patients were analyzed and the values obtained correlated well with an automated differential pH method (gamma = 0.989).     

输血治疗对急性有机磷农药中毒时血清胆碱酯酶以及阿托品用药的影响

目的：探讨急性有机磷农药中毒时输血治疗对血清胆碱酯酶活力的影响以及对于阿托品用药时间的影响。方法：对54例入院时血清胆碱酯酶活力〈2 000KU/L（正常值4 000~11 000KU/L）的有机磷农药中毒患者进行回顾分析,其中给予输血治疗组34例,未输血组20例。分别统计输血组及未输血组患者血清胆碱酯酶活力恢复至2 800KU/L（正常值70%）以及3 600KU/L（正常值90%）以上的时间,并统计两组患者脱离阿托品的时间。结果：输血组在血清胆碱酯酶活力恢复至2 800KU/L以及3 600KU/L以上所需的时间均小于未输血组,差异有统计学意义（P〈0.01）,两组患者脱离阿托品所需的时间差异无统计学意义（P〉0.05）。结论：急性有机磷农药中毒时输血治疗能显著提高血清胆碱酯酶活力恢复速度,但对脱离阿托品的时间无明显影响,即对疾病病程无明显影响。     

Butyrylcholinesterase: association with the metabolic syndrome and identification of 2 gene loci affecting activity

BACKGROUND: Plasma cholinesterase activity is known to be correlated with plasma triglycerides, HDL- and LDL-cholesterol, and other features of the metabolic syndrome. A role in triglyceride metabolism has been proposed. Genetic variants that decrease activity have been studied extensively, but the factors contributing to overall variation in the population are poorly understood. We studied plasma cholinesterase activity in a sample of 2200 adult twins to assess covariation with cardiovascular risk factors and components of the metabolic syndrome, to determine the degree of genetic effects on enzyme activity, and to search for quantitative trait loci affecting activity. METHODS AND RESULTS: Cholinesterase activity was lower in women than in men before the age of 50, but increased to activity values similar to those in males after that age. There were highly significant correlations with variables associated with the metabolic syndrome: plasma triglyceride, HDL- and LDL-cholesterol, apolipoprotein B and E, urate, and insulin concentrations; gamma-glutamyltransferase and aspartate and alanine aminotransferase activities; body mass index; and blood pressure. The heritability of plasma cholinesterase activity was 65%. Linkage analysis with data from the dizygotic twin pairs showed suggestive linkage on chromosome 3 at the location of the cholinesterase (BCHE) gene and also on chromosome 5. CONCLUSIONS: Our results confirm and extend the connection between cholinesterase, cardiovascular risk factors, and metabolic syndrome. They establish a substantial heritability for plasma cholinesterase activity that might be attributable to variation near the structural gene and at an independent locus.     

Intraindividual variation of PSA,free PSA and complexed PSA in a cohort of patients with prostate cancer managed with watchful observation

OBJECTIVE: To determine the intraindividual variation of prostate-specific antigen (PSA) isoforms in prostate cancer patients managed conservatively with watchful observation. METHODS: Patients with favorable clinical parameters (stage T1b-T2b N0 M0, Gleason score 相似文献   

老年重症社区获得性肺炎患者血清胆碱酯酶的变化及意义

目的 探讨血清胆碱酯酶(CHE)活性在老年重症社区获得性肺炎患者中的变化及临床意义.方法 检测重症肺炎组、普通肺炎组和健康对照组血清CHE活性, 将他们按性别分为男女两组,再分别比较男性、女性组中重症肺炎组、普通肺炎组和健康对照组血清CHE活性.结果 男性组血清CHE活性:重症肺炎组<普通肺炎组<健康对照组(P<0.01);女性组血清CHE活性:重症肺炎组<普通肺炎组<健康对照组(P<0.01).结论 老年重症社区获得性肺炎患者血清胆碱酯酶活性降低,降低程度与肺部炎症的严重程度密切相关.     

The estimation of serum cholinesterase in the presence of anti-cholinesterase insecticides

Six methods have been employed for the assay of serum cholinesterase in the presence of a number of anti-cholinesterase insecticides, of which three were carbamates and two organophosphorus compounds. Inhibition of cholinesterase activity was demonstrated in every case, but four of the methods underestimated the degree of inhibition.It was found that if serum samples to which four of the five insecticides had been added were left at room temperature for 24 hours there was almost complete recovery of the cholinesterase activity. This did not occur if the samples were stored at ?15°.On the basis of these studies two methods are recommended for the estimation of serum cholinesterase in the presence of anti-cholinesterase insecticides.     

Plasma cholinesterase activity in a healthy population group with no occupational exposure to known cholinesterase inhibitors: relative influence of some factors related to normal inter- and intra-individual variations

Inter-individual variations of plasma cholinesterase were analysed in 193 apparently healthy volunteers (122 males, 71 females) with no known occupational exposure to cholinesterase inhibitors. Multiple regression analysis and analysis of variance showed statistically significant effects on the individual plasma cholinesterase activity by body weight, height, sex, and ChE-1 phenotype (but not by age or electrophoretic phenotype). Varying body weight explained one-fourth of the observed biological variance (s2total). The intra-individual variations during an 8-month period varied substantially from one individual to another (3% to 41% of the subject's mean activity); a repeated-measures analysis of variance showed a within-person variance (s2intra) = 5% of s2total. Intra-individual variation was uninfluenced by the variables that influence the inter-individual variance. A model for a 'standardized' plasma cholinesterase in which the combined effects of the four significant variables, ChE-1 phenotype, sex, body weight, and height are eliminated, is proposed for comparisons of plasma cholinesterase activities in unmatched population groups, e.g. within environmental or occupational medicine.     

血清胆碱酯酶监测用于农药中毒后两种急救方法的比较研究

目的通过观察农药中毒患者的反跳情况及血清胆碱酯酶连续监测,对适当改造后的空肠营养管与鼻胃管组患者进行比较研究。方法将65例口服农药中毒患者随机分为空肠管组、鼻胃管组和对照组,比较3组患者反跳发生例数以及血液胆碱酯酶活性百分比变化、达到正常值低限活力60%以上需要天数等差异。结果空肠管组反跳发生5例,胆碱酯酶活力恢复至60%以上需要（10.04±1.21）d;鼻胃管组反跳发生10例,胆碱酯酶活力恢复至60%以上需要（11.17±1.58）d;对照组反跳发生10例,胆碱酯酶活力恢复至60%以上需要（11.35±2.05）d;3组均在6d内发生反跳,由此连续对胆碱酯酶活力动态监测并对6d内的结果进行统计分析,3组从第1天开始差异即有统计学意义。结论经过适当改造后空肠管与鼻胃管组相比能有效降低农药中毒患者反跳发生率,促进胆碱酯酶活力的恢复。     

Cholinesterase in serum and low density lipoprotein of hyperlipidemic patients.

Cholinesterase activity in the low density lipoprotein fraction of serum is increased in types IIa, IIb and IV hyperlipoproteinemic patients, whereas only types IIb and IV show increases in serum cholinesterase activity. In obese patients, cholinesterase activity is increased both in the serum and low density lipoprotein fraction only when hyperlipidemia is present. Cholinesterase activity is also found to increase in proportion with increases in low density lipoprotein, cholesterol, and triglycerides both in the serum and low density lipoprotein fraction. We suggest on the basis of these findings that cholinesterase has a function in lipid and lipoprotein metabolism.     

Cholinesterase activity of motor end plate in human skeletal muscle

The activity and properties of cholinesterase of the motor end plate in human intercostal muscle were studied in the isolated muscle membrane. This preparation was used because cholinesterase activity of the membrane preparation was localized in the motor end plate without contamination of cholinesterase of other muscle components. Under the experimental conditions, cholinesterase in a human end plate hydrolyzed 1.21 x 10(8) molecules of acetylcholine per msec, which is smaller than hydrolysis of 2.69 x 10(8) by a motor end plate of rat intercostal muscle. Studies with cholinesterase inhibitors and specific substrates indicated that about 90% of cholinesterase of human motor endplates is acetylcholinesterase, and about 10% is pseudocholinesterase. The end plate cholinesterase had an optimal pH of 7.8 and a Michaelis-Menten constant of 4.15 mmoles/liter, and was stable at 4 degrees C for at least 4 wk. Motor end plates were estimated to contain only about 2% of the total cholinesterase activity of human intercostal muscle, compared with about 20% in rat tibialis anterior muscle. The difference is due to the lower cholinesterase activity of the motor end plate and higher cholinesterase activity of non-end plate components in human muscle than in rat muscle. The isolated muscle membrane provides a useful preparation for the study of the properties of motor end plate in human skeletal muscle.     

Quantification and phenotyping of serum cholinesterase by enzyme antigen immunoassay: methodological aspects and clinical applicability

An enzyme antigen immunoassay for a specific determination of serum cholinesterase is described. Polyclonal and monoclonal antibodies against cholinesterase have been used. Hydrophobic binding of the specific antibody to a microtitre plate was followed by incubation with the samples, and the activity of the bound cholinesterase was assayed by the Ellman method. The procedure has been optimized and characterized, with respect to antigen specificity, and the applicability of the assay for cholinesterase phenotyping is demonstrated. The cholinesterase activities, dibucaine-, scoline-, fluoride- and urea numbers were comparable with established reference values. The high sensitivity and specificity of the assay has been used for determination of cholinesterase in amniotic and cerebrospinal fluids, and its applicability in clinical medicine is indicated.     

Serum beta -- lipoproteins: studies in a patient and in guinea pigs after the ingestion of organophosphorus compounds.

A patient admitted to this hospital with Parathion poisoning had a marked reduction in serum cholinesterase activity and concentration of low density lipoprotein. The enzyme and the lipoprotein levels returned to normal with clinical recovery. Guinea pigs treated with phospholine iodide showed depressed levels of serum cholinesterase and beta-lipoprotein. It is suggested that the decrease in beta-lipoproteins is due to the decrease in cholinesterase activity.     

胆碱酯酶活性检验在脂肪肝中的应用

目的通过检测、分析脂肪肝患者血清中胆碱酯酶（CHE）、丙氨酸氨基转移酶（ALT）、γ-谷氨酰转移酶（GGT）及血脂的含量变化,证实CHE在脂肪肝诊断中的应用价值。方法在健康组与脂肪肝组中测定CHE浓度及ALT、天门冬氨酸氨基转移酶（AST）、GGT等酶类活力及对总胆固醇（TC）、三酰甘油（TG）进行了测定,并对结果进行统计学分析。结果脂肪肝患者CHE活性上升最显著（P＜0.001）,TC、TG也明显增高（P＜0.01）。结论提示CHE是常规生化指标中测定脂肪肝最敏感的检测项目,联合检测CHE活性及相关项目对脂肪肝的诊断有重要临床价值。     

Serum calcium ion activity. Some aspects on methodological differences and intraindividual variation.

Sera were analyzed for calcium ion activity on the Orion 99-20 and SS-20 systems. Samples from 84 healthy subjects were analyzed on both systems and, because of a change of electrode composition, 74 of them were reanalyzed after this change. Additional 89 were analyzed on only SS-20. The distribution of serum calcium ion activity was close to Gaussian. The difference between the 99-20 and SS-20 readings was 0.048+/-0.017 mmol/liter (range -0.01 to 0.08) before the electrode change and -0.085+/-0.027 mmol/liter (range -0.14 to 0.02) after. The reference ranges were 1.02--1.23 mmol/liter for 99-20 and 0.93--1.20 mmol/liter for SS-20 before the electrode change. The following characteristics may contribute to differences in the readings: higher temperature, higher flow rate, new calcium and reference electrodes, new liquid junction construction and a new pumping procedure. For 74 subjects the determination of serum calcium ion activity (99-20 system) was performed with a five year interval and the difference between the first and second measurements was -0.0046+/-0.0168 mmol/liter (mean +/-SD), ranging from -0.04 to 0.03 mmol/liter. This corresponded to an intraindividual variation of 1.5%. The corresponding variations for serum total calcium and corrected calcium were 4.8% and 3.3% respectively.     

The effect of storage at different temperatures on cholinesterase activity in human serum

The effect of storage on the catalytic concentration of cholinesterase and on the reference values of cholinesterase in human serum were studied. When serum was stored at room temperature (20 degrees C), at 4 degrees C and at - 20 degrees C (one year) there was no change in catalytic activity. Even after nine times freezing and thawing (over nine weeks) the catalytic activity was unaffected. The average reference value was significantly higher for males than for females (3.11 +/- 0.57 vs 2.50 +/- 0.43 kU/l).     

An alternative approach to the prevention of succinyldicholine-induced apnoea

Succinyldithiocholine was utilized as a substrate analogue of succinyldicholine to study normal and atypical serum pseudocholinesterase (EC 3.1.1.8). In the method, the enzyme acts on succinyldithiocholine to release thiocholine, which reacts with 5,5'-dithio-bis-(2-nitrobenzoic acid) to produce a coloured compound with maximal absorbance at 410 nm. The procedure appears to be precise (between-day analysis gives a coefficient of variation between 1.1 and 3.7%) and amenable to automation, permitting routine use in any laboratory. The reference interval for 300 healthy adults with "usual" cholinesterase genotype was estimated to be 34-77 U/l, with a significant difference between males and females (40-78 U/l for men and 33-76 U/l for women, p less than 0.01). The median activity in 105 individuals with "heterozygous" cholinesterase genotype was 22 U/l (range 5-35 U/l), and for 14 "atypical" homozygotes 1.5 U/l (range 1-4 U/l). The assay with succinyldithiocholine may offer a direct procedure for preoperative screening of individuals with an abnormal response to the muscle relaxant succinyldicholine, thus avoiding the determination of genotype by measurement of inhibitor numbers.     

Interindividual and intraindividual variability in acetylation: characterization with caffeine

The degree of interindividual and intraindividual variability in acetylator activity was investigated with caffeine used as a probe of enzyme activity. Acetylator phenotype and relative N-acetyltransferase activity were estimated in 46 subjects by measuring the urinary ratio of two metabolites, AFMU/1-MX, after a single 300 mg oral dose of caffeine on five separate occasions. Thirty homozygous slow (rr) and 15 heterozygous rapid (Rr) acetylators were identified. The degree of interindividual variability in acetylator activity was observed to be a mean of 32% (range 27% to 36%) and 20% (range 11% to 29%) in the rr and Rr groups, respectively. The mean intraindividual variation on repetitive measurement was 19% (range 6% to 49%) in the rr and 14% (range 7% to 24%) in the Rr acetylator group. Four subjects had apparent changes in acetylator activity with time such that they were unable to be assigned to any one acetylator group. Two of these four subjects exhibited apparent homozygous rapid acetylator activity intermittently during the 5-week trial. This variability may explain, in part, some of the high degree of patient variability observed in the toxicity, efficacy, and drug-related disease associated with acetylated drugs and environmental toxins.     

Serum cholinesterase activity in patients with burns.

Serum cholinesterase activities were measured in 300 patients with thermal injuries. The samples were drawn immediately upon admission and thereafter daily until the time of the patients' discharge or death. According to the burn severity a characteristic decrease was noted during the first days. The decline during the first 24 hours as well as its value (measured 24 hours after admission) was found to be correlated with the total body surface area burned. In all patients the decrease in cholinesterase activity persisted for days, but in patients with inhalation trauma this decrease was significantly greater than in patients without lung injury. It seems that serum cholinesterase activity reflects not only the presence of an inhalation trauma. The cholinesterase measurement seems to be also a good method to observe the course of illness after a burn injury. Our data suggest a correlation between cholinesterase activity and morbidity. The inhalation trauma aggravates the thermal trauma.