Evaluation of the revised serum calcium procedure used with the Du Pont automatic clinical analyzer

We evaluated a revised serum calcium method (o-cresolphthalein complexone) used with the Du Pont aca. Our results correlated well with those obtained by atomic absorption spectrometry. Within-run and day-to-day coefficients of variation were 0.5 and 1.5%, respectively. Color produced and calcium concentration are linearly related and the relation is not affected by hemolysis, lipemia, or icterus.

Automated method for determining calcium disodium edetate in iodinated contrast media parenterals

An automated method, based on the chelating reaction of calcium disodium edetate with zirconium and the subsequent determination of excess zirconium reacted with xylenol orange, was developed. The procedure is applicable to parenterals consisting of iodinated contrast media. Familiar modules of an automated analyzer were used, but the method can be performed manually if the sample load does not warrant automation. The pH should be controlled between 0.3 and 0.5. No interferences were encountered. Twenty samples per hour can be run on prepared sample solutions. The precision of a single determination, at the 95% confidence level was plus or minus 0.008 mg/ml with a limit of detection near 0.40 mg/ml.

Use of a rapid brain-sampling technique in a physiologic preparation: effects of morphine, ketamine, and halothane on tissue energy intermediates

A new method of rapid sampling of brain tissue, "freeze-blowing," has been used to compare the neurochemistry of the brain during anesthesia with that in the awake state. The method avoids anoxia associated with the sampling process. Physiologic variables, including body temperature, blood-gas tensions and blood pressure, were carefully monitored and controlled in the experimental animals. None of the agents tested (halothane, morphine, and ketamine) reduced the brain tissue high-energy phosphate reserved. All three drugs doubled glucose levels. Morphine lowered both lactate and the lactate/pyruvate ratio. Uniformly, the three anesthetic agents led to twofold increases of brain cyclic 3'-5' adenosine monophosphate concentrations. These changes suggest a possible role for cyclic nucleotides in central neurotransmission.

High sensitivity automated sequence determination of polypeptides

We report the development of a high sensitivity Edman method for use in the automated protein sequenator. With the use of a radioactive coupling reagent, [35S]phenylisothiocyanate, and minor modifications in the sequenator program, sequence analyses have been performed on nanomole quantities of protein. The radioactive phenylthiohydantoin derivatives produced in the degradation are identified at the 10 to 100 pmol level by two-dimensional thin layer chromatographic procedures with autoradiography and are quantitated by scintillation counting. This high sensitivity approach, which is about 100 times more sensitive than conventional automated Edman procedures, has allowed continuous amino acid assignments for 15 or more cycles on quantities of protein less than 5 nmol. It has been employed in the NH2-terminal sequence analysis of several proteins whose sequences were previously undetermined.

Amino acid residues of serum and CSF protein in multiple sclerosis. Clinical application of statistical discriminant analysis

Statistical discriminant analysis of the amino acid compostion of serum and cerebrospinal fluid (CSF) proteins provides an objective method for distinguishing between normal controls and patients with multiple sclerosis (MS). This method also results in a high degree of specificity in separating MS patients from those with other diseases of the nervous system. The CSF protein serine residue is highly correlated with the CSF IgG and holds promise for a more sensitive diagnostic test for MS than the currently used CSF IgG. Finally, the serum/CSF protein serine ratio seems to correlate best with clinically determined degree of activity for the disease, the most active cases having the lowest ratio. These results suggest that investigation of the amino acid composition of serum and CSF protein in multiple sclerosis and, possibly, in other diseases might lead to the development of clinically useful tests of diagnosis and degree of activity of MS.

A correction to the autoanalyzer data for quantitative agglutination measurements

The AutoAnalyzer was used for quantitative measurements of antibody agglutinating activity by a Polybrene agglutination technique. Since the continuous flow system introduces an experimental error to the determination of true agglutination percentage, it is necessary to apply a correction factor. The experimental method of correction is described.

Automated thermoluminescence reader. I. Technical construction and function

An automated TLD reader has been developed and constructed. The dosimeter material consisting of LiF is permanently enclosed in thin-walled teflon tubes. Dosimeters are identified by numbers, which simplifies individual calibration. A calibration radiation source consisting of a cylinder (90Sr-90Y) is used for the calibrations. The function of the reader and the calibration radiation source is described, and the method of measurement briefly reported.

Simultaneous assay of neutral sugars and amino sugars by an automatic sugar analyzer: applications to glycoproteins

The simultaneous assay of neutral sugars and amino sugars commonly found in glycoproteins is described. The automatic sugar analyzer used for the determination is based on the ion-exchange chromatography of sugar-borate complexes on a strong anion-exchange resin. The sugars are identified with the orcinol/sulfuric acid reagent. While less than 40 nmol of mannose, fucose, galactose, glucose, xylose, or arabinose is sufficient for analysis at least 200 nmol mannosamine, glucosamine, or galactosamine is required; acidic monosaccharides cannot be determined. The technique of sugar analysis is applied to structural studies on natural compounds, e.g. the monosaccharide composition of lichenan and the carbohydrate moiety of the glycoproteins ovomucoid and Collocalia mucoid.

A rapid and specific method for the determination of oxytocinase (cystine aminopeptidase) activity using continuous flow analysis and S-benzyl-L-cysteine-p-nitroanilide as substrate

1. An automated method is described for the assay of pregnancy serum cystine aminopeptidase (Oxytocinase, E.C. 3.4.1.10) using continuous flow analysis. S-Genzyl-L-cysteine-p-nitroanilide, the most highly specific substrate so far available for oxytocinase is employed in this assay. Comparison with the manual method from which it has been developed, gave a correlation coefficient of 0.98. Reaction of oxytocinase on the substrate liberated p-nitroaniline, the absorption of which is measured at 410nm. 2. Blank values are eliminated by the incorporation of a dialyzer in the manifold design and thereby effectively increasing the rate of assay sample to 40 per hour. The lag phase (a) of the continuous flow analysis is 0.17 min while the exponential phase (b) is 0.31 min. Using a 2:1 sample to wash ration the carry-over is 3% at a 95% of steady states.

The advantages of automated blood alcohol determination by head space analysis

Precision, specificity and interpretation of the results are reported. Using only few different columns all volatile substances of importance are detected specifically, With new developed stationary phases, graphite as support, the analysis could be done with a sufficient resolution in 1 min. The absolute peak height of the internal standard or the amount of acetaldehyde determines the status of the sample and enables a very precise analysis of alcohol in blood

Collaborative study of a semiautomated method for the analysis of acenocoumarol, phenprocoumon, and potassium warfarin tablets

This collaborative study was undertaken to determine if the anticoagulants acenocoumarol, phenprocoumon, and potassium warfarin could be analyzed by the automated analysis system described in the collaborative study for the analysis of sodium warfarin and dicumarol. Collaborators were supplied with a composited tablet sample of each anticoagulant. Results agreed well with the National Formulary methods for phenprocoumon and potassium warfarin, and an unpublished method for acenocoumarol. For acenocoumarol, coefficients of variation on individual sets of data ranged from 0.30 to 1.94% For phenprocoumon, coefficients of variation ranged from 0.52 to 1.20%. For potassium warfarin, coefficients of variation ranged from 0.54 to 1.79%. The results of this study show that acenocoumarol, phenprocoumon, and potassium warfarin can be analyzed by the official AOAC method for the analysis of sodium warfarin and dicumarol tablets.

Collaborative study of a semiautomated colorimetric analysis of digoxin tablets

A semiautomated thiobarbituric acid colorimetric analysis for digoxin was collaboratively studied by 6 laboratories. Collaborators were supplied with 3 composites of tablets of different dosage levels. Results agreed with the USP method. The coefficients of variation ranged from 0.46 to 2.73%. The method has been adopted as official first action.

Automated analysis of vitamin C in pharmaceutical products

The determination of total vitamin C in the form of both l-ascorbic acid (AA) and dehydroascorbic acid (DHAA) present in pharmaceutical preparations has been automated. Total vitamin C (completely oxidized to DHAA) was determined by reaction with 2,4-dinitrophenylhydrazine while blanks utilized the same reagent after reducing all DHAA to AA. The automated method was applicable to a variety of multivitamin preparations including those containing iron and copper. The mean recovery of L-ascorbic acid added to 11 multivitamin preparations was 99.4% with a coefficient of variation of 2.5%. In the analysis of these products, results obtained by the automated method were essentially the same as those obtained by the original manual method. For preparations containing no copper salts, the results were also comparable to those obtainable by titration with 2,6-dichloroindophenol except in 1 product which contained some DHAA.

Determination of isonicotinic acid hydrazide in serum

A method for the determination of isonicotinic acid hydrazide is given. The hydrazide is complexed with cupric ions and condensated with an aromatic aldehyde substituted in ortho-position with a hydroxyl group. The method is adapted to the AutoAnalyzer equipment of first and second generation. Pilot measurements on the pharmacokinetic behaviour of isonicotinic acid hydrazide are presented.