scholarly journals Comparison of Two Storage Methods for the Analysis of Cholinesterase Activities in Food Animals

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Kasim Abass Askar ◽  
A. Caleb Kudi ◽  
A. John Moody
Keyword(s):  
Significant Inhibition ◽  
Mean Difference ◽  
Altman Plot ◽  
Choline Esters ◽  
Cholinesterase Activities ◽  
The Mean ◽  
Storage Methods ◽  
Lower Limits ◽  
Hydrolysis Of

Cholinesterases (ChE) are specialized carboxylic ester hydrolases that catalyse the hydrolysis of choline esters. They are classified into either acetylcholinesterase (AChE) or butyrylcholinesterase (BChE). Determination of ChE in the tissues is the appropriate tool for the diagnosis of organophosphorus and carbamate exposures. In general, a significant inhibition was seen in both AChE and BChE activities after 6 months of freezing at −80°C and after 3 months of freezing at −20°C. Linear regression of mean AChE and BChE was observed in all individual samples during the months of the two freezing methods. Bland and Altman plot of the ratios of the two freezing methods have showen the mean difference between the two freezing methods to be 8.8, and SD was 144.7 and −127.6 for upper and lower limits, respectively, for liver, while in muscle the mean difference was 1.5 and SD was 32.5 and −28.9 for upper and lower limits, respectively.

A Versatile Radioimmunoassay for the Determination of Serum Oestriol in Pregnancy

1973 ◽  
Vol 10 (1-6) ◽  
pp. 159-166 ◽  
Author(s):  
J. E. H. Stafford
Keyword(s):  
Normal Pregnancy ◽  
Optimum Conditions ◽  
Random Series ◽  
The Mean ◽  
Hydrolysis Of ◽  
Selection Of ◽  
In Pregnancy

A versatile radioimmunoassay for serum oestriol in pregnancy has been developed which requires 10 μ| of serum (for total) or 50 μ| (for unconjugated). Selection of the optimum conditions for the hydrolysis of serum oestriol conjugates, the isolation of free oestriol, the displacement of tritiated oestriol by cold oestriol and the separation of the free and bound fractions is described. Total oestriol levels doubled between weeks 34 and 38 of normal pregnancy, very little change occurring in the mean level after the 38th week of gestation. In a random series of pregnancy sera there was a significant correlation between total and unconjugated oestriol.

scholarly journals Development of an automated method for the determination of human paraoxonase1 activity

2011 ◽  
Vol 5 (2) ◽  
pp. 217-224 ◽  
Author(s):  
Manel Araoud ◽  
Fadoua Neffeti ◽  
Wahiba Douki ◽  
Abderraouf Kenani ◽  
Mohamed Fadhel Najjar
Keyword(s):  
Spectrophotometric Method ◽  
Storage Temperature ◽  
Organophosphorus Pesticides ◽  
Pon1 Activity ◽  
Activity Assay ◽  
Automated Method ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Hydrolysis Of

Abstract Background: Human plasma paraoxonase1 (PON1) is an esterase catalyzing the hydrolysis of organophosphorus pesticides and other xenobiotics. The aims of this study were to develop a rapid method to determinate PON1 activity, evaluate some interference, and study the influence of storage temperature on PON1 activity assay. Methods: Measurement of PON1 activity was performed for 369 samples by measuring the hydrolysis of paraoxon using a spectrophotometric method adapted on konelab 30 ⃞. Results: The developed method facilitates the determination of PON1 activity at the rate of more than 200 samples per hour, and it is linear between 2 and 900 IU/L. Intra and inter-assay imprecision coefficients of variation were 2% and 5% respectively. PON1 activity in serum was correlated with those in heparinized plasma (r = 0.994, p < 0.001) and in plasma/EDTA (r = 0.962, p < 0.001). The mean inhibition of the PON1 activity was, by EDTA/K3, 41 ± 10 %. There was not significant PON1 activity variation after 40 days of storage at -20°C or at +4 ⃞ C. There were no substantial interferences from haemoglobin, jaundice and hyperlipidemia. Conclusion: The developed method is reliable, reproducible, and suitable. It can also be performed on heparinized plasma for the determination of PON1 activity. Hence, it may be useful for assaying PON1 activity in several intoxications such as organophosphorus, sarin, and soman nerve agents.

scholarly journals The accuracy of the determination of terrestrial refraction from reciprocal zenith angles

1979 ◽  
Vol 89 ◽  
pp. 203-212 ◽  
Author(s):  
K. Ramsayer
Keyword(s):  
Mean Difference ◽  
Mean Deviation ◽  
Refraction Coefficient ◽  
Refraction Angle ◽  
Observation Station ◽  
The Mean ◽  
True Values ◽  
Better Than

To investigate the accuracy of the determination of terrestrial refraction from reciprocal zenith angles and astronomical latitudes and longitudes at both ends of a line a test net with lines from 4 km to 23 km was observed and three dimensionally adjusted. As the measurements of the zenith angles were repeated every hour 40 times in an average the adjusted values were taken as a substitute for the true values. It is shown, that the mean refraction coefficient k, which is changing from k = 0.10 at day up to k = 0.34 at night, and the corresponding refraction angle can be determined very accurately, if both angles are measured simultaneously. Observations with day light are better than observations in the night. For observations with day light the mean difference between the true refraction angle at the observation station and the mean refraction angle of the observed line was smaller than ± 1″ independent of the length of the line. That means that the mean deviation of the true effective refraction coefficient in the observation station and the mean refraction coefficient of the observed line was inverse proportional to the distance.

The Determination of Thiamine in Small Amounts of Whole Blood and Serum by a Simplified Thiochrome Method

1965 ◽  
Vol 11 (6) ◽  
pp. 617-623 ◽  
Author(s):  
Than Myint ◽  
Harold B Houser
Keyword(s):  
Whole Blood ◽  
Serum Concentrations ◽  
Serum Samples ◽  
Adsorption Column ◽  
The Mean ◽  
Mean Differences ◽  
Hydrolysis Of ◽  
Sample Dilution ◽  
Low Serum

Abstract This simplified thiochrome method for the determination of thiamine eliminates deproteinization, sample dilution (other than reagent), and purification by adsorption column; pH need not be adjusted as it is automatically controlled. The method depends upon the hydrolysis of whole blood and serum with N HCI, N/10 HCI, and diastase enzyme. Reproducibility was good; the mean differences (± S.D.) between duplicate blood and serum samples were 2.36 ± 2.87 and 1.5 ± 1.70 mµg./ml., respectively. Recovery of added thiamine ranged from 94 to 104% with a mean of 99.5 ± 3.41%. Storage of hydrolysates for 30 days did not change the results, and low serum concentrations could be measured in serum. Whole blood and serum values of thiamine in 44 healthy adults ranged from 11.3 to 47.8 mµg./ml. (mean, 29.3) and from trace amounts to 20.5 mµg./ml. (mean, 10.2), respectively.

scholarly journals A New Gas Chromatography–Mass Spectrometry Method for Simultaneous Determination of Total and Free trans-3′-Hydroxycotinine and Cotinine in the Urine of Subjects Receiving Transdermal Nicotine

1999 ◽  
Vol 45 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Allena J Ji ◽  
George M Lawson ◽  
Rodger Anderson ◽  
Lowell C Dale ◽  
Ivana T Croghan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Simultaneous Determination ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Transdermal Nicotine ◽  
Selective Ion Monitoring ◽  
Lower Limits ◽  
Hydrolysis Of

Abstract trans-3′-Hydroxycotinine (THOC) has been recognized as the most abundant metabolite of nicotine. In an attempt to assess THOC and cotinine (COT) concentrations during nicotine transdermal therapy, we developed a new quantitative gas chromatography–mass spectrometry (GC–MS) method for simultaneous determination of total and free THOC and COT in human urine. The method utilizes the following: (a) hydrolysis of conjugated THOC and COT by β-glucuronidase; (b) basic extraction of THOC and COT with mixed dichloromethane and n-butyl acetate; (c) derivatization of THOC with bis(trimethylflurosilyl)acetamide; and (d) separation and identification by GC–MS with selective ion monitoring. Lower limits of quantification for the assay were 50 and 20 μg/L for THOC and COT, respectively. The intra- and interassay CVs were 4.4% and 11% for THOC, and 3.9% and 10% for COT at 1000 μg/L. The results from six consecutive 24-h urine collections in 71 subjects administered daily transdermal nicotine doses of 11, 22, and 44 mg showed that, on average, free THOC was 76% of total THOC and free COT was 48% of total COT in all subjects. THOC is the major metabolite of nicotine and constitutes 20% of total nicotine intake at steady state, whereas urinary nicotine and COT excretion were 8% and 17%, respectively. The method is useful for simultaneous determination of free and total THOCand COT and can be used to assess the urinary excretion of these metabolites during transdermal nicotine therapy.

scholarly journals Simultaneous Determination and Pharmacokinetic Study of Quercetin, Luteolin, and Apigenin in Rat Plasma after Oral Administration of Matricaria chamomilla L. Extract by HPLC-UV

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoxv Dong ◽  
Wei Lan ◽  
Xingbin Yin ◽  
Chunjing Yang ◽  
Wenping Wang ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Oral Administration ◽  
Simultaneous Determination ◽  
Rat Plasma ◽  
Maximum Plasma Concentration ◽  
Maximum Plasma ◽  
Matricaria Chamomilla ◽  
The Mean ◽  
Lower Limits

A simple and sensitive HPLC-UV method has been developed for the simultaneous determination of quercetin, luteolin, and apigenin in rat plasma after oral administration of Matricaria chamomilla L. extract. The flow rate was set at 1.0 ml/min and the detection wavelength was kept at 350 nm. The calibration curves were linear in the range of 0.11–11.36 μg/ml for quercetin, 0.11–11.20 μg/ml for luteolin, and 0.11–10.60 μg/ml for apigenin, respectively. The intraday and interday precisions (RSD) were less than 8.32 and 8.81%, respectively. The lower limits of quantification (LLOQ) of the three compounds were 0.11 μg/ml. The mean recoveries for quercetin, luteolin, and apigenin were 99.11, 95.62, and 95.21%, respectively. Stability studies demonstrated that the three compounds were stable in the preparation and analytical process. The maximum plasma concentration (Cmax) was 0.29 ± 0.06, 3.04 ± 0.60, and 0.42 ± 0.10 μg/ml, respectively. The time to reach the maximum plasma concentration (Tmax) was 0.79 ± 0.25, 0.42 ± 0.09, and 0.51 ± 0.13 h, respectively. The validated method was successfully applied to investigate the pharmacokinetics study of quercetin, luteolin, and apigenin in rat plasma after oral administration of M. chamomilla extract.

scholarly journals Validity assessment of a portable anthropometer to measure length in 24-month children from the 2015 Pelotas Birth Cohort

2020 ◽  
Vol 23 (15) ◽  
pp. 2711-2716
Author(s):  
Thaynã R Flores ◽  
Andréa D Bertoldi ◽  
Luiza IC Ricardo ◽  
Cauane Blumenberg ◽  
Laísa R Moreira ◽  
...  
Keyword(s):  
Cohort Study ◽  
Birth Cohort ◽  
Gold Standard ◽  
Mean Difference ◽  
Birth Cohort Study ◽  
Altman Plot ◽  
Bland Altman Plot ◽  
Validity Assessment ◽  
The Mean

AbstractObjective:This study aimed to assess the validity of a portable anthropometer against the gold standard among 2-year-old infants from the 2015 Pelotas (Brazil) Birth Cohort.Design:Birth cohort study.Setting:A fixed Harpenden® infant anthropometer was considered as the gold standard for measuring infant length due to its greater precision and stability. The portable SANNY® (model ES2000) anthropometer was the instrument to be validated. The acceptable mean difference in length between the anthropometers was 0·5 cm. In order to compare length estimates, the interviewers carried out two length measures for each of the anthropometers (fixed and portable) and for each child. The mean of the two lengths was calculated for each anthropometer, and their difference was calculated.Participants:A subsample of 252 24-month-old members of the 2015 Pelotas (Brazil) birth cohort study.Results:Children’s mean age was 23·5 months. According to Bland–Altman plot, there were no differences in overall lengths between the portable and the fixed anthropometers, or in lengths according to sex. There was a high overall concordance between the length estimates of the fixed and portable anthropometers (ρ = 0·94; 95 % CI 0·92, 0·95).Conclusions:The portable anthropometer proved to be accurate to measure the length of 24-month-old infants, being applicable to studies using the same standardised protocol used in the present study.

scholarly journals Agreement of Two Different Laboratory Methods Used to Measure Electrolytes

2011 ◽  
Vol 3 (02) ◽  
pp. 104-109 ◽  
Author(s):  
Venencia Albert ◽  
Arulselvi Subramanian ◽  
Kanchana Rangarajan ◽  
Ravindra Mohan Pandey
Keyword(s):  
Cross Sectional Study ◽  
Mean Difference ◽  
Universal Method ◽  
Limits Of Agreement ◽  
Serum Samples ◽  
Cross Sectional ◽  
Laboratory Methods ◽  
Flame Photometer ◽  
The Mean

ABSTRACT Aim: The aim of our study was to do an agreement analysis of two different laboratory methods used to measure electrolytes i.e., between the ISE based Beckman Coulter Synchron CX9 PRO Biochemistry analyzer and RAL′s Ion3 Flame Photometer (Técnica para el Laboratorio, Barcelona, Spain), in serum samples. Materials and Methods: This cross sectional study was done over a period of three months from September′09 through December′09 on routine biochemistry samples. A total of 6492 samples were received for routine biochemistry analysis from those 630 blood samples were randomly processed for this study. Two ml of sample was taken in a plain gel tube (LABTECH Disposables, Ahmedabad, India), centrifuged and further processed using both systems within one hour of the sampling to obtain the Na and K concentrations in the samples. The bias and variability of differences in measured values were analyzed according to Bland and Altman method. Results: Flame photometry method has drawbacks such as low throughput, requires manual operation, is a time consuming procedure. Ion selective electrodes technique is a more universal method for the high throughput determination of electrolytes in physiological samples; Beckman Coulter Synchron CX9 PRO is an example of such a system. The mean difference between the two methods (standard minus test) and 95% limits of agreement for sodium in serum was -7.8±17.3 (-42.2 to 26.6) and in urine was -22±41 (-104 to 60). Similarly, the mean difference between the two methods for potassium values in serum was found to be -0.25±0.75 (-1.75 to 1.25) and in urine was -5.3±38.9 (-83.1 to 72.5). With 95% confidence interval, the value of sodium and potassium as determined by both the methods lie between the upper and lower limit showing 95% limits of agreement. Conclusion: Good degree of agreement was seen on comparing the two methods for measuring the electrolytes; the use of Synchron CX9 in place of Flame photometer for electrolyte analysis in serum and urine is justified or use the two interchangeably.

scholarly journals Determination of plasma volume in anaesthetized piglets using the carbon monoxide (CO) method

2002 ◽  
Vol 36 (3) ◽  
pp. 344-350 ◽  
Author(s):  
J. K. Heltne ◽  
M. Farstad ◽  
T. Lund ◽  
M. E. Koller ◽  
K. Matre ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Plasma Volume ◽  
Evans Blue ◽  
Mean Difference ◽  
Limits Of Agreement ◽  
Administration System ◽  
Mean Values ◽  
Controlled Ventilation ◽  
The Mean

Based on measurements of the circulating red blood cell volume (VRBC) in seven anaesthetized piglets using carbon monoxide (CO) as a label, plasma volume (PV) was calculated for each animal. The increase in carboxyhaemoglobin (COHb) concentration following administration of a known amount of CO into a closed circuit re-breathing system was determined by diode-array spectrophotometry. Simultaneously measured haematocrit (HCT) and haemoglobin (Hb) values were used for PV calculation. The PV values were compared with simultaneously measured PVs determined using the Evans blue technique. Mean values (SD) for PV were 1708.6 (287.3)ml and 1738.7 (412.4)ml with the CO method and the Evans blue technique, respectively. Comparison of PVs determined with the two techniques demonstrated good correlation ( r = 0.995). The mean difference between PV measurements was -29.9 ml and the limits of agreement (mean difference ±2SD) were -289.1 ml and 229.3 ml. In conclusion, the CO method can be applied easily under general anaesthesia and controlled ventilation with a simple administration system. The agreement between the compared methods was satisfactory. Plasma volume determined with the CO method is safe, accurate and has no signs of major side effects.

scholarly journals Prospective Comparison of Point-of-Care Device and Standard Analyzer for Monitoring of International Normalized Ratio in Outpatient Oral Anticoagulant Clinic

2018 ◽  
Vol 24 (7) ◽  
pp. 1153-1158 ◽  
Author(s):  
Bushra Moiz ◽  
Anila Rashid ◽  
Muhammad Hasan ◽  
Lena Jafri ◽  
Ahmed Raheem
Keyword(s):  
Point Of Care ◽  
Hospital Setting ◽  
International Normalized Ratio ◽  
Mean Difference ◽  
Altman Plot ◽  
Prospective Comparison ◽  
Self Testing ◽  
The Mean ◽  
Coaguchek Xs ◽  
Laboratory Analyzer

Point-of-care testing (POCT) coagulometers are increasingly being used in the hospital setting and patients’ self-testing. We determined the agreement of prothrombin time international normalized ratio (INR) results by POCT coagulometer and laboratory instrument through a comparative analysis and investigated whether the results of POCT coagulometer can reliably be used without being confirmed by standard laboratory analyzer. A total of 200 INR measurements by POCT coagulometer (CoaguChek XS Pro) and laboratory analyzer (Sysmex CS2000i) were compared using Passing-Bablok regression analysis and Bland-Altman plot. Agreement of the INR measurement was further analyzed in relation to dosing decision. The correlation of INR measurements between CoaguChek XS Pro and Sysmex CS2000i was excellent (correlation coefficient = 0.973). The overall mean difference was 0.21 INR ± 0.32 (range: 1.7-0.44). The mean difference was found to get increased as INR results increased and was 0.09 in the subtherapeutic range (≤1.9 INR), 0.29 INR in the therapeutic range (2.0-3.0 INR), while 0.4 INR in the supratherapeutic range (>3.0 INR). The overall agreement was excellent (κ = 0.916) and overall 11 (5.5%) of 200 INR measurements showed a difference in dosing decision between the 2 instruments. The positive bias of POC-INR is evident in the supratherapeutic range which could affect the dosing decision requiring confirmation with the laboratory INR measurement.

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