A More Sensitive Automated Method for Determination of Ornithine Carbamoyltransferase Activity in Human Serum

1975 ◽  
Vol 21 (6) ◽  
pp. 754-757 ◽  
Author(s):  
Kathleen J Clayson ◽  
James S Fine ◽  
Paul E Strandjord
Keyword(s):  
Kinetic Studies ◽  
Sample Volume ◽  
Ornithine Carbamoyltransferase ◽  
Hepatocellular Injury ◽  
Carbamoyl Phosphate ◽  
Automated Method ◽  
Upper Limit ◽  
Threefold Increase ◽  
Assay Conditions

Abstract Ornithine carbamoyltransferase (EC 2.1.3.3) activity is a sensitive, specific indicator of hepatocellular injury. This paper describes development of an improved automated procedure for measurement of this activity. Triethanolamine—ethylenedlaminetetraacetate is used as a buffer, and activity is determined by measuring the concentration of the product, citrulline. Kinetic studies have been performed to determine optimal pH and L-ornithine and carbamoyl phosphate concentrations. Recovery of citrulline was studied. The upper limit of normal obtained in a study of 106 blood-bank donors was 6 U/liter. The automated procedure developed as a result of these studies, in which optimal assay conditions are used, produces a threefold increase in sensitivity and permits use of a sample volume of 1 ml.

Kinetic determination of serum haptoblobin with a centrifugal analyzer.

1976 ◽  
Vol 22 (12) ◽  
pp. 1962-1967 ◽  
Author(s):  
T S Kickler ◽  
P F Gong ◽  
G F Johnson ◽  
H M Solomon
Keyword(s):  
Binding Capacity ◽  
Regression Line ◽  
Normal Serum ◽  
Least Squares Regression ◽  
Kinetic Determination ◽  
Automated Method ◽  
Hemoglobin Binding ◽  
Total Peroxidase Activity ◽  
Assay Conditions

Abstract We describe a method for determining haptoglobin with a centrifugal analyzer that is based on haptoglobin combining stoichiometrically with hemoglobin to form a complex that has peroxidase-like activity proportional to the quantity of haptoglobin present. Under assay conditions, unbound hemoglobin exhibits only a small fraction of the total peroxidase activity. Activity is measured colorimetrically at 405 nm after reaction with o-dianisdine and ethyl hydrogen peroxide. The procedure is standardized by saturating aknown amount of hemoglobin with a serum whose hemoglobin binding capacity exceeds the amount of hemoglobin in the assay system. The mean and mean within-run precision of our method, determined by performing 17 replicate assays of both a pooled normal serum and a 10-fold dilution of the serum, was 1.13 g/liter (CV, 2.9%), and 106 mg/liter (cv, 5.8%), respectively. The 95 percentile estimate of the normal range by our method is 0.45-1.85 g/liter hemoglobin binding capacity. When results by our automated method were compared to those by a manual method [Scand. J. Clin. Lab. 2nvest. 18, 80 (1965)], the slope of the unweighted linear least-squares regression line was .970 the y-intercept 26 mg/liter, and the correlation coefficient .995.

Spectrophotometry of tissue thromboplastin in cerebrospinal fluid.

1981 ◽  
Vol 27 (8) ◽  
pp. 1427-1430 ◽  
Author(s):  
E A Hische ◽  
J A Tutuarima ◽  
H J van der Helm
Keyword(s):  
Cerebrospinal Fluid ◽  
Detection Limit ◽  
Factor Xa ◽  
Calcium Buffer ◽  
Upper Limit ◽  
Coefficients Of Variation ◽  
Complex Source ◽  
Tissue Thromboplastin ◽  
Assay Conditions

Abstract We describe a two-stage method for measuring thromboplastin in cerebrospinal fluid, based on the amidolytic determination of the generation rate of Factor Xa. We investigated the effect of variations in the duration of incubation, and in pH, temperature, and concentrations of calcium, buffer, and prothrombin complex (source of Factors VII and X). Optimal assay conditions are specified. The detection limit is 6 units/L and the results indicate an upper limit of normal of 14 units/L. The coefficients of variation were 7.7% within-day and 9.2--16.0% day-to-day, depending on the concentration.

Automated enzymatic determination of sodium in serum

1993 ◽  
Vol 39 (3) ◽  
pp. 500-503 ◽  
Author(s):  
R Quiles ◽  
J M Fernández-Romero ◽  
E Fernández ◽  
M D Luque de Castro ◽  
M Valcárcel
Keyword(s):  
Sampling Rate ◽  
Sample Volume ◽  
Sodium Ion ◽  
Ion Selective Electrodes ◽  
Direct Potentiometry ◽  
Automated Method ◽  
Enzymatic Determination ◽  
Flame Spectrometry ◽  
Beta Galactosidase

Abstract An automated method based on the principles of flow-injection analysis is proposed for the enzymatic determination of sodium ion in serum. The method relies on the activation of beta-galactosidase by the analyte. The features of the proposed method include linear range between 1 and 1700 mumol/L, a sampling rate of 50 samples/h, a sample volume of 50 microL, and the absence of interferences from species usually present in serum. The results obtained were consistent with those provided by widely used methods such as those based on flame spectrometry and direct potentiometry with ion-selective electrodes.

Characterization of the Periodate Oxidation of Glycerol and Related Compounds, and Application toward Determination of Serum Triglyceride Concentrations

1974 ◽  
Vol 20 (6) ◽  
pp. 645-648 ◽  
Author(s):  
D A White ◽  
D S Miyada,1 ◽  
R M Nakamura
Keyword(s):  
Periodate Oxidation ◽  
Serum Triglyceride ◽  
Kinetic Studies ◽  
Initial Reaction ◽  
Automated Method ◽  
First Order Kinetics ◽  
Excess Substrate ◽  
Related Compounds

Abstract The periodate oxidation of glycerol was examined to see if it could be quantitated from its yield of an equimolar amount of formaldehyde. End-product studies, carried out with glycerol and related compounds by an automated method, indicated that oxidation was almost completed within the time span of the analysis. Kinetic studies at pH 4.0 with excess substrate indicated pseudo-first-order kinetics with respect to periodate consumption. The rate constant for glycerol is 57 x 10-2 min-1; the reaction with glycolaldehyde was too rapid to measure. These results indicate that it is the initial reaction of periodate with glycerol that is rate-limiting instead of the secondary reaction with glycolaldehyde, and that these reactions occur concomitantly. We conclude that it is extremely unlikely that any practicable glycerol analysis can be based on the equimolar formation of formaldehyde.

Quantitative Radioisotope Measurement of Duodenogastric Reflux in Patients with Ulcer or Gastrectomized for Ulcer

1985 ◽  
Vol 24 (03) ◽  
pp. 107-110
Author(s):  
M. Pääkkönen ◽  
S. Aukee ◽  
K. Korhonen ◽  
A. Pääkkönen ◽  
E. Länsimies ◽  
...  
Keyword(s):  
Gamma Camera ◽  
Background Activity ◽  
Bile Reflux ◽  
Duodenogastric Reflux ◽  
Upper Limit ◽  
Visual Evidence ◽  
Biochemical Measurement

SummaryIn this work the duodenogastric reflux was quantified as the amount of radioactivity entering the stomach after an i.v. administration of 99mmTc-HIDA in ulcer patients and in patients who had undergone BI gastrectomy. The results were compared with visual evidence of gastric activity in the gamma camera images and biochemical determination of gastric bile reflux. The method is useful in quantifying the reflux if the activity is above the background activity. It allows the determination of an upper limit for the reflux when the reflux is evident visually. Only two or three images are needed for the quantitation. No correlation was found between biochemical measurement of fasting bile reflux in the stomach and radioisotopic quantification.

Stability Indicating Liquid Chromatographic Method for the Determination of Fenofibrate and its Application to Kinetic Studies

2013 ◽  
Vol 5 (4) ◽  
pp. 1866-1874
Author(s):  
K. Srinivasa Rao ◽  
Keshar N K ◽  
N Jena ◽  
M.E.B Rao ◽  
A K Patnaik
Keyword(s):  
Degradation Products ◽  
Kinetic Studies ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Zero Order Kinetics ◽  
Relative Standard ◽  
Liquid Chromatographic

A stability-indicating LC assay method was developed for the quantitative determination of fenofibrate (FFB) in pharmaceutical dosage form in the presence of its degradation products and kinetic determinations were evaluated in acidic, alkaline and peroxide degradation conditions. Chromatographic separation was achieved by use of Zorbax C18 column (250 × 4.0 mm, 5 μm). The mobile phase was established by mixing phosphate buffer (pH adjusted 3 with phosphoric acid) and acetonitrile (30:70 v/v). FFB degraded in acidic, alkaline and hydrogen peroxide conditions, while it was more stable in thermal and photolytic conditions. The described method was linear over a range of 1.0-500 μg/ml for determination of FFB (r= 0.9999). The precision was demonstrated by relative standard deviation (RSD) of intra-day (RSD= 0.56– 0.91) and inter-day studies (RSD= 1.47). The mean recovery was found to be 100.01%. The acid and alkaline degradations of FFB in 1M HCl and 1M NaOH solutions showed an apparent zero-order kinetics with rate constants 0.0736 and 0.0698  min−1 respectively and the peroxide degradation with 5% H2O2 demonstrated an apparent first-order kinetics with rate constant k = 0.0202 per min. The t1/2, t90   values are also determined for all the kinetic studies. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of FFB in pharmaceutical formulations.  

Spectrophotometric Determination of Alendronate Sodium by using Sodium-1,2-Naphthoquinone-4-Sulphonate

2012 ◽  
Vol 4 (4) ◽  
pp. 1563-1568
Author(s):  
Sagar Suman Panda ◽  
Ravi Kumar B V V ◽  
D Patanaik
Keyword(s):  
Spectrophotometric Method ◽  
Absorption Maximum ◽  
Dosage Form ◽  
Dosage Forms ◽  
Alendronate Sodium ◽  
Colored Complex ◽  
Pharmaceutical Dosage Forms ◽  
Recovery Study ◽  
Assay Conditions

A simple, precise and accurate spectrophotometric method was developed for analysis of the osteoporesis drug alendronate sodium (ALS). The method is based on reaction of the drug with sodium-1,2-naphthoquinone-4-sulphonate (NQS) in presence of alkali to form a brown colored complex giving absorption maximum at 525 nm. The drug obeyed Beer’s law in the range of 5-70 µg/ml with a correlation coefficient of 0.999. The LOD and LOQ values are 1.7 µg/ml and 5.0 µg/ml, respectively. The average recoveries for recovery study were found to be in the range of 99.37%-100.46%. The R.S.D. values for intraday and inter-day precision were found to be 0.48 and 0.62, respectively. The optimized assay conditions were applied successfully for determination of ALS in pharmaceutical dosage forms. No interference was observed from the excipients present in the dosage form. The method is statistically validated as per the ICH requirements.  

Sign in / Sign up

Export Citation Format

Share Document