bluuebunny/crossref_metadata_2025_split huggingface dataset:
Continuous Flow Electrometric Glucose Determination
Authors: Wilde C. E. , Sewell P. 
Published: February 2014

A continuous flow system for the determination of glucose in blood or plasma using glucose oxidase is described. Oxygen uptake is measured by a Clarke electrode linked through an oxygen monitor and pH meter to a recorder. The omission of a peroxidase-chromogen step increases the specificity of the assay which gives very good correlation with the hexokinase-NADPH method. The system has a high sensitivity which can be adjusted by changing the oxygen-nitrogen ratio of the segmenting gas. It is useful when measuring ‘true glucose’ in low concentration and gives a linear response within the range 0 to 200 mg/100 ml. The electrode response time limits the rate of analysis to 30 samples per hour if adequate precision is to be maintained. The advantages of a closed continuous flow system over manual electrometric methods are discussed.
A Versatile Radioimmunoassay for the Determination of Serum Oestriol in Pregnancy
Authors: Stafford J. E. H. 
Published: February 2014

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.
Evaluation of a Kit (Thyrolute) for the Combined Determination of Serum Total Thyroxine and Sequential Free Thyroxine Index using Sephadex G-25 and 125I-thyroxine
Authors: Howorth P. J. N. , McKerron C. G. , Marsden P. 
Published: February 2014

A new kit (Thyrolute, Ames) for the combined determination of serum total thyroxine (T-4) and sequential free thyroxine index (F.T.I.) using Sephadex G-25 and 125I-thyroxine was evaluated in 136 patients and normal subjects. The T-4 determination was virtually identical to that used in the Ames Tetralute kit and had a similar accuracy and precision. The sequential F.T.I. was compared with a two-stage F.T.I. The two F.T.I.s showed highly significant correlations in the various groups of patients except euthyroid women with raised thyroxine-binding globulin (TBG) (pregnant or oral contraceptive). The overlap found for the sequential F.T.I. between euthyroid, hypothyroid, and thyrotoxic patients was slightly inferior (9%) to that found with the two-stage F.T.I. (6%), but its diagnostic success rate was higher than that of the serum T-4 determination alone. Serial observations of serum T-4 and sequential F.T.I. were also made on eight patients receiving carbimazole therapy for hyperthyroidism. The sequential F.T.I. showed complete parallelism with serum T-4 regardless of thyroid status, so that it was of no practical value in these patients. It was concluded that the sequential F.T.I kit would be of most value in the smaller hospital laboratory lacking facilities for the radioimmunoassay of thyroid hormones and thyroid stimulating hormone.
Assay of Cortisol in Serum by Competitive Protein Binding without Solvent Extraction
Authors: Morris R. , Holder G. 
Published: February 2014

A method for the determination of serum cortisol by competitive protein binding is proposed in which solvent extraction is replaced by heat inactivation. Results obtained by the new technique correlate well with those obtained by solvent extraction. A saving in manipulative time and glassware is effected when the method is applied in a routine assay.
Paracetamol Estimation: Comparison of a Quick Colorimetric Method with a Standard Spectrophotometric Method
Authors: Wiener K. 
Published: February 2014

A new colorimetric method for the estimation of plasma paracetamol was slightly modified and compared with a standard spectrophotometric method. Good correlation and no significant difference was found between results by the two procedures. Precision, accuracy, and recovery by the colorimetric method were acceptable. Several drugs were tested for interference in the colorimetric method. Some sulphonamide preparations potentially interfere. On the other hand it is less susceptible than the spectrophotometric method to interference by certain other drugs. The speed and simplicity of the colorimetric method, together with its satisfactory performance, make it a worthwhile alternative to the spectrophotometric procedure.
Automation of the Turbidimetric Determination of Serum Lipase
Authors: Puukka M. , Puukka Raija 
Published: February 2014

A turbidimetric procedure for the determination of serum lipase activity has been adapted for use on a System Olli 3000 analyser. In this automated procedure 50 μl of serum and standard sample, and a buffer solution, are pipetted into disposable cuvettes in the measurement block. The block is then preincubated for 15 minutes at 37°C, and after simultaneous addition of the olive oil emulsion, the absorbances of the cuvettes are recorded simultaneously for two minutes at 405 nm. Using the program ‘block standards’ for the calibration of the method the results are ready in graphic form and expressed as U/l within about five minutes of the addition of the olive oil. A total of 60 patient sera can be analysed in half an hour. The method is linear up to at least 1000 U/l, and the reference values are between 11 and 140 U/l. A comparison of the method with the modification of the Cherry-Crandall titrimetric method gives a value of 0·87 for the correlation coefficient and the regression equation y = 0·97x + 12 (n = 191). Within-run precision (CV) for sera with mean enzyme activities of 149 and 354 U/l was found to be 4·2% and 3·4%, respectively (n = 20), and day-to-day precision 5·0% (mean activity = 339 U/l, n = 18).
Hydroxyproline Metabolism in Type II Hyperprolinaemia
Authors: Similä S. 
Published: February 2014

Hydroxyproline metabolism was studied in two patients with type II hyperprolinaemia (HP II) using oral loadings of hydroxyproline or hydroxyproline-ornithine. Δ1-pyrroline-3-hydroxy-5-carboxylic acid (3 OH-PC) and Δ1-pyrroline-5-carboxylic acid (PC) were identified in the urine. The urinary excretion of both 3-OH-PC and PC increased in HP II patients but not in healthy controls during oral loading of hydroxyproline and hydroxyproline-ornithine. The plasma level of proline in patients with HP II is very high but the hydroxyproline concentration is normal or only slightly increased. Therefore one can assume that hydroxyproline is converted to pyrrole-2-carboxylic acid, which is excreted in urine as a glycine conjugate. In this study it was demonstrated that the highly elevated plasma level of proline in one of the patients with HP II decreased greatly after hydroxyproline-ornithine load; this change was followed by a 40-fold rise in urinary excretion of proline.
A Simple Robust Assay for Testosterone in Male Plasma Using an 125I-Radioligand and a Solid-Phase Separation Technique
Authors: Dyas J. , Read G. F. , Riad-Fahmy Diana 
Published: February 2014

A radioimmunoassay for testosterone in male plasma utilising a gamma-emitting radioligand and a solid-phase antiserum is described. The radioligand is testosterone-3-(O-carboxymethyl)-oxime coupled to 125I-iodohistamine, and the solid-phase antiserum is prepared by coupling antitestosterone-3-bovine serum albumin to cyanogen bromide activated cellulose. The new procedure retains much of the specificity associated with a published, specific radioimmunoassay using an antiserum raised against testosterone-11α-BSA and a tritium radioligand and incorporating a dextran-coated charcoal separation procedure; values obtained by the two procedures are in excellent agreement (r = 0·98, n = 20). The combination of an 125I-radioligand and a solid-phase separation technique greatly increases sample throughput and has the further advantage of reduced running costs and a greater potential for automation. The method gives satisfactory levels of sensitivity, precision, and accuracy.
Clinical Usefulness of the Simultaneous Localisation of the Isoenzymes of Alkaline Phosphate and γ-Glutamyl Transferase
Authors: Baines M 
Published: February 2014

Simultaneous localisation of the isoenzymes of alkaline phosphatase and γ-glutamyl transferase was carried out on 173 serum samples from patients with hepatobiliary and bone disease to determine (i) if a better discrimination of the underlying pathology could be obtained by such an approach, and (ii) if the pathology suggested by the alkaline phosphatase isoenzyme separation could help in determining the cellular location of the γ-glutamyl transferase isoenzymes. It was found that the localisation of the γ-glutamyl transferase isoenzymes had, with a few exceptions, little advantage over the measurement of the total activity but that some evidence concerning the cellular location of the γ-glutamyl transferase isoenzymes could be gained by such an approach. There was support for the view that the α2-migrating isoenzyme is derived from the liver parenchymal cytoplasm, but little support for the view that the α1-migrating isoenzyme is predominantly the induced microsomal enzyme or that the β-migrating isoenzyme is the result of impaired billiary secretion.
A Comparison of the Phosphotungstate Magnesium Precipitation and Heparin-Manganese Precipitation Procedures for Estimating High-Density Lipoprotein Cholesterol
Authors: Calvert GD , Yeates Rosemary A , Mannik Tuna 
Published: February 2014

The phosphotungstate-MgCl2 method for precipitating very low density and low density lipoproteins from plasma precipitates up to about 7 % of high density lipoprotein. The heparin-MnCl2 method, used at a final MnCl2 concentration of 0092 mol/l, does not seem to precipitate any high density lipoprotein but precipitates essentially all apolipoprotein B containing very low density and low density lipoprotein. When the final concentration of MnCl2 is 0046 mol/l, precipitation of apolipoprotein B containing very low density and low density lipoprotein is frequently incomplete. The herapin-MnCl2 method, when the MnCl2 final concentration is 0·092 mol/l, is the preferred method for high density lipoprotein cholesterol measurement if the cholesterol assay is unaffected by either heparin or MnCl2. High density lipoprotein cholesterol results, using this method, are higher than with the phosphotungstate MgCl2 method and lower than with the heparin MnCl2 method when the MnCl2 final concentration is 0·046 mol/l.
Valproic Acid Estimation by Enzyme Immunoassay
Authors: Elyas Abdulmajid A , Goldberg Valerie D , Ratnaraj Neville , Lascelles Peter T 
Published: February 2014

Blood samples from patients on long-term sodium valproate (Epilim) therapy were analysed for valproic acid by two procedures, enzyme immunoassay (EMIT)* and gas-liquid chromatography (GLC). A critical evaluation of the effects of anticoagulants added to specimens was performed in addition to studies on reagent specificity, accuracy, and precision. EMIT valproic acid reagent showed high specificity, and there was a good correlation between results obtained by EMIT and GLC over a wide range of concentrations. The accuracy and precision of EMIT assay was good over the therapeutic range of valproic acid. The presence of the anticoagulant EDTA or of fluoride/oxalate produced a bias towards high results for valproic acid as compared with those obtained from the analysis of serum.
Serum Alcohol Dehydrogenase Activity in Liver Diseases
Authors: Khayrollah Ahlam A , Al-Tamer Y Y , Taka M , Skursky L 
Published: February 2014

The normal level of human serum alcohol dehydrogenase (EC 1.1.1.1) (ADH) activity which is not measurable by conventional methods was found to be within the range 0·07–0·56 U/l when measured by a sensitive method based on a coenzyme recycling reaction. In different liver diseases the normal upper limit of serum ADH activity was found to be exceeded up to 70 times. Although ADH activity under pathological conditions usually parallels that of other enzymes, e.g., sorbitol dehydrogenase (EC 1.1.1.14) (SDH) and alanine transaminase (EC 2.6.1.2) (ALT), its relative elevation above the upper normal limit is generally greater, particularly in the early stages of viral hepatitis. Observations on some patients also suggested that very early stages of liver damage, caused by drugs or secondary malignancy, could be detected by increases of serum ADH activity when the activities of some other liver specific enzymes were still within their normal values. A pilot experiment on rats, intoxicated with carbon tetrachloride, showed that serum ADH activity could reflect acute liver parenchymal damage more sensitively than SDH and ALT activity.
Evaluation of Erythrocyte Protoporphyrin and Zinc Protoporphyrin as Micro Screening Procedures for Lead Poisoning Detection
Authors: Bush B , Doran Donna R , Jackson K W 
Published: February 2014

Seven hundred and three blood samples from children were analysed for lead by Delves cup atomic absorption, for protoporphyrin by solvent extraction and fluorescence, and for zinc protoporphyrin with two manufacturers' models of an automated front-face fluorimeter (haematofluorimeter). The power of protoporphyrin analysis for predicting the level of lead in blood was found to be poor. Up to 30% of children with lead concentrations of ≥40 g/100 ml (≥1·93 μmol/l) and nearly 60% of children with ≥30 μg/100 ml (≥1·45 μmol/l) would remain undetected if protoporphyrin analysis were used for screening with an action level of 60 μg/100 ml (1·07 μmol/l) for the porphyrin analysis. The predictive power of protoporphyrin analyses improves with the age of the child, indicating that the less expensive protoporphyrin test may be acceptable for older children, if by this means a large population of children at risk can be screened.
The T4:TBG Ratio: A Re-Evaluation with Particular Reference to Low and High Serum TBG Levels
Authors: Attwood E C , Atkin G E 
Published: February 2014

The thyroxine: thyroxine-binding globulin (T4: TBG) ratio is now an established part of the biochemical investigation of thyroid function. Reference ranges have been reported for euthyroid subjects with TBG levels within the range 6–16 mg/l. Routine assay of TBG on all thyroid function tests in this laboratory has suggested that, in patients with low or high TBG levels, the established reference ranges for T4:TBG may not be strictly applicable. A retrospective study has been made of a large number of thyroid function requests, including serum total T4, free T4, TBG, and TSH assays. Evidence is presented to show that in subjects with a TBG level of less than 8 mg/l the reference range for T4: TBG is elevated. Similarly, in subjects with a TBG greater than 16 mg/l, the reference range for T4: TBG is lowered. The data suggest that it is necessary to quote a T4: TBG reference range based on small increments of TBG levels or to relate total T4 reference ranges to those increments.
Further Experience with Free Thyroxine Assays with Particular Reference to Pregnancy
Authors: Tuttlebee Jw 
Published: February 2014

The Amerlex FT4 radioimmunoassay has been assessed. It is simple, quick, and precise. The assay is as good as the FTI or the Immo Phase FT4 assay in hyperthyroid, hypothyroid, or elderly subjects and in women on oral contraceptives. In acute illness and pregnancy, however, over half the values lie below the euthyroid reference range. Further work on blood samples obtained from pregnant subjects demonstrated that while FT4 values given by the Immo Phase and Liquisol kits remain constant, those given by the GammaCoat, Amerlex, and Lisophase kits show a significant decrease with gestation. What the ‘true’ FT4 is in acute illness and in pregnancy remains an open question.
Infrared Analysis of Renal Calculi: A Comparison with Conventional Techniques
Authors: Corns Cathryn M 
Published: February 2014

The analysis of renal calculi is an oft-neglected corner of clinical biochemistry. This study compares results obtained by the conventional qualitative methods with results from quantitative and infrared methods and also investigates the role of x-ray diffraction analysis. Infrared spectroscopy, using a KBr disc technique, was found to be the single most useful method, being fast, simple to learn, using little sample, and in general permitting positive identification of most of the components found in renal calculi. A major advantage is that this method has approximately equal sensitivity for oxalate and phosphate, unlike the wet chemical methods. Infrared analysis is also useful in identifying the spurious materials sometimes submitted as renal calculi. X-ray diffraction analysis is not a technique that is routinely available, but it does provide information not given by other methods, eg, distinguishing Ca(COO)2·H2O from Ca(COO)2·2H2O. For complete analysis a combination of methods was adopted; carbonate is tested for using a microchemical technique, calcium, magnesium, and phosphate are quantitated by routine methods, and infrared analysis is used to detect oxalate and organic components. It must be emphasised that any method is only as good as the sample used, and different areas of the calculus must be analysed separately if useful results are to be obtained.
Standards versus Standardised Methods in Enzyme Assay
Authors: Jansen R T P , Jansen A P 
Published: February 2014

In a trial of the Netherlands coupled external/internal quality control program a control serum and an enzyme standard were analysed over a period of eight weeks, five times each week. Five enzymes were determined: alkaline phosphatase, creatine kinase, lactate dehydrogenase, alanine aminotransferase, and γ-glutamyltransferase. The measured values in the serum were converted to the standards. Those laboratories using the recommended methods also submitted their non-transformed serum values. The following standardisation techniques have been compared: ( a) no standardisation of methodology but use of enzyme standards; ( b) standardisation of methodology; ( c) standardisation of methodology combined with use of an enzyme standard. Results were submitted to analysis of variance. Standardisation of methodology did not yield smaller interlaboratory variation than the standardisation with enzyme standards. In this trial a combination of both standardisation techniques yielded generally better results. Results for γ-glutamyltransferase indicate that standardisation of substrate may be necessary apart from the use of an enzyme standard. The preparation of stable enzyme standards is stressed.
Relation between the Urinary Cortisol: Creatinine Ratio and Hypoglycaemia
Authors: Ohwovoriole A E , Nairn I M , Baird J D 
Published: February 2014

The relationships between (i) urinary free cortisol and urinary creatinine concentrations and (ii) the urinary cortisol/creatinine ratio (UCCR) and various glycaemic levels were studied in three groups—normal, insulin-stressed and insulin-treated diabetic subjects. In non-hypoglycaemic subjects, there was a significant positive linear correlationship between urinary free cortisol and urinary creatinine excretion, but in the presence of hypoglycaemia, this relationship was lost. The highest mean urinary cortisol/creatinine ratio (UCCR) was found in subjects after an insulin tolerance test (ITT). The mean post-ITT UCCR was significantly greater than the mean for the pre-ITT samples. There was a significant negative correlation between capillary blood glucose levels at 03.00 and the UCCR of the overnight urine samples of insulin-treated diabetic subjects. We conclude that there is a definite increase in the UCCR after hypoglycaemia in subjects with adequate adrenocortical response to hypoglycaemia and that determination of the UCCR could be helpful in the detection of nocturnal hypoglycaemia.
Role of Glucose Homeostatic Mechanisms in Viral Infections
Authors: Aiyathurai J E J , Wong H B , Quak S H , Sothy S P , Chio Lee Foon , Jacob E , Doraisingham Santhiramathy 
Published: February 2014

Though normoglycaemia is thought to indicate adequacy of cellular glucose content, ketoacidosis occurs in viral infections even in the presence of normo- and hyperglycaemia. These wide variations in glucose concentrations may reflect the patients' adaptive abilities in situations where glucose transport is impaired by viruses. Hypoglycaemia would suggest poor adaptation and hyperglycaemia good adaptation. Increased free fatty acid (FFA) concentrations and enzyme activity are probable adaptive mechanisms. If so, they should decrease with hyperglycaemia***producing infusions. Profiles of glucose, FFA, enzymes, and fever over 19 days in 24 children with viral infections are reported. On admission 87.5% were normo- or hyperglycaemic with increased FFA, AST, LDH, and fever (p < 0.005) when compared with values 19 days later. With infusions that produced hyperglycaemia, there was clinical recovery with a decrease in FFA and enzyme activity. The hyperglycaemia observed in 56.5% therefore points to glucose homeostatic mechanisms being geared to maintain the intracellular milieu. Hence normoglycaemia does not always indicate cellular glucose adequacy.
Sample Collection and Processing for the Assay of Plasma Renin Activity
Authors: Roulston J E , Wathen C G , Sanger Bella , Muir A L 
Published: February 2014

Plasma renin activity was measured in samples collected in lithium heparin, sodium heparin, and ethylenediaminetetraacetate. The samples were incubated under two widely used sets of conditions to generate angiotensin I, and the results were compared. Under certain incubation conditions, the absence of ethylenediaminetetraacetate from the sample tube produced low plasma renin activity values. This was obviated by using an alternative incubation medium and was not, therefore, due to direct inhibition of renin by heparin. These lower values were not seen in samples from patients receiving captopril. This suggests that the discrepant values were due to some angiotensin I conversion to angiotensin II and lower homologues in the incubates. Sodium heparin samples compared closely with lithium heparin samples, indicating that the presence of lithium is not significant. These results show that, provided the incubation conditions are suitably modified, samples collected into lithium or sodium heparin can be used for measurement of plasma renin activity.
Serum Free Thyroxine Concentrations in Subjects with High Circulating Levels of Thyroxine-Binding Globulin
Authors: Ashwell K , Hopton M R , Harrop J S 
Published: February 2014

Serum free thyroxine (FT4) and thyroid hormone-binding protein concentrations were measured in pregnant women, stilboestrol-treated patients, and subjects with congenital thyroxine-binding-globulin (TBG) excess. In pregnant and stilboestrol-treated patients matched for TBG concentrations, serum FT4 concentrations measured by the Amerlex technique and by calculation, were reduced, as also was the total thyroxine (TT4)/TBG ratio. In congenital TBG excess Amerlex and calculated FT4 concentrations were normal whereas the TT4/TBG ratio was low. In contrast to the Amerlex method, FT4 concentrations by the Immophase procedure were normal in pregnant and stilboestrol-treated individuals and high in congenital TBG excess. We conclude that (i) reduced FT4 concentrations in pregnancy are related to an oestrogen effect rather than to some other pregnancy-associated factor, (ii) the TT4/TBG ratio gives a misleading indication of FT4 concentration in congenital TBG excess, and (iii) that when TBG concentrations are raised Immophase gives higher FT4 values than Amerlex or calculation when each is compared to FT4 values in their normal respective control group.