bluuebunny/crossref_metadata_2025 huggingface dataset:
Lamellar Body Phospholipid Content of Amniotic Fluid: A Possible Index of Fetal Lung Maturity
Authors: Duck-Chong Coral G.
Published: February 2014

Lamellar bodies, produced by secretory cells in the alveolar epithelium, are the major source of surfactant phospholipid. As the fetal lung matures, the membranous content of the lamellar bodies is secreted into the alveolar spaces and passes into the amniotic fluid, from which it can be isolated in a morphologically recognisable form. A method is described for the rapid isolation of a lamellar body fraction from amniotic fluid using a small air-driven clinical ultracentrifuge. The lamellar body phospholipid content of amniotic fluid increases towards the end of gestation, but the time of onset and the rate of this increase show wide individual variation. Preliminary results suggest that the lamellar body phospholipid content of amniotic fluid may be a useful index of fetal lung maturity.
Serum Antioxidant Activity in Normal and Abnormal Subjects
Authors: Cranfield L. M. , Gollan J. L. , White A. G. , Dormandy T. L.
Published: February 2014

Serum antioxidant activity (AOA) was correlated with the serum caeruloplasmin and serum copper concentration and with the total and available serum iron-binding capacity in 313 normal and abnormal subjects. In all groups except in patients with Wilson's disease (hepatolenticular degeneration) there was a highly significant direct correlation between serum AOA and serum caeruloplasmin concentration. A statistically significant direct correlation between serum AOA and the available iron-binding capacity of serum was found only in normal subjects and in children with thalassaemia major and iron overload. There was no correlation between serum AOA and the serum tocopherol concentration in any of the groups studied.
Long-Term Studies on Immunoreactive Human Melatonin
Authors: Arendt Josephine , Wirz-Justice Anna , Bradtke Jose , Kornemark Marianne
Published: February 2014

Immunoreactive melatonin has been studied in normal human volunteers, both men and women, at different times of day and different times of the year. At 2400, but not at 0800 or 1200, there are very large inter-individual variations in mean levels, the maximum difference being fivefold. Intra-individual variations are seen at different times of the year at 2400 and 0800, with low values in spring and autumn and high values in summer and winter.
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 New Method for the Determination of Plasma Phenylalanine
Authors: Trinder Paul
Published: February 2014

Two hundred microlitres of plasma is deproteinised, and chloride is removed with TCA/silver iodate. After centrifugation the phenylalanine in the protein-free extract is oxidised to benzaldehyde with buffered sodium metaperiodate. The benzaldehyde is extracted into iso-octane, and the absorbance of the organic layer is measured at 240 nm. The method gives good agreement with a paper chromatographic method at normal and elevated levels of phenylalanine. All the reagents are stable indefinitely, and a single determination can be completed in 15 minutes.
A Simple Direct Solid-Phase Enzymeimmunoassay for Cortisol in Plasma
Authors: Hindawi Ragiha Kalil , Gaskell SJ , Read GF , Riad-Fahmy Diana
Published: February 2014

A simple, direct solid-phase enzyme-labelled immunoassay for plasma cortisol was established using horseradish peroxidase/cortisol 21-hemisuccinate conjugate as ‘enzyme label’. The antiserum, raised against a cortisol 21-hemisuccinate/bovine serum albumin conjugate, was coupled to cellulose to facilitate separation of free and bound steroid. Solvent extraction was avoided by the use of heat denaturation of the cortisol-binding globulin. This assay had a lower limit of sensitivity of 16·6 nmol/l and satisfied the standard criteria of accuracy and precision. Cortisol concentrations determined by enzymeimmunoassay were in excellent agreement with a gas liquid chromatography/mass spectrometry procedure (r = 0·98, n = 19) and also with the radioimmunoassay in current use (r = 0·95, n = 20). Cortisol levels after ACTH stimulation and dexamethasone suppression in various subjects are presented. This enzymeimmunoassay is particularly applicable to the routine determination of plasma cortisol in small clinical laboratories or in those with a fluctuating workload.
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.
Human Brain Aldolase C4 Isoenzyme: Purification, Radioimmunoassay, and Distribution in Human Tissues
Authors: Willson V J C , Thompson R J
Published: February 2014

The nervous system specific isoenzyme of fructose-1, 6-diphosphate aldolase (E.C.4.1.2. 13), aldolase C4, has been purified from human brain, and a sensitive radioimmunoassay has been developed for its detection. This assay is also capable of detecting other hybrid isoenzymes containing the C subunit but not the A4 isoenzyme. A systematic survey of human organs has shown that immunoreactive aldolase C is present in all human organs but at levels less than 2 % of those found in human brain; especially low levels occur in kidney, skeletal muscle, lung, and thyroid tissue. The presence of aldolase C in other organs apart from nervous tissue is unlikely to be explicable by innervation alone since significant quantities are found in erythrocytes. The high degree of localisation of aldolase C4 in nervous tissue makes it a suitable marker for cell damage within the central nervous system.
An Assessment of the Corning Electrophoretic Procedure for High Density Lipoprotein Cholesterol Estimation
Authors: Bullock D G , Carter T J N , Cosgrove Carmel M , Hughes Susan V
Published: February 2014

The electrophoretic procedure for high density lipoprotein cholesterol determination recently introduced by Corning Medical has been assessed. The results correlated well with those obtained by phosphotungstate/Mg precipitation and ultracentrifuge procedures, but the between-batch CV was 6% in the clinically important range below 1 mmol/l. The densitometer, which must be carefully aligned before use for this analysis, seemed sensitive to variations in the plates and patterns produced. The technique required great care, especially with timing, and appeared expensive.
Formulation of Optimal Conditions for an Immunonephelometric Assay
Authors: Whicher J T , Blow C
Published: February 2014

A method is described for establishing the optimal conditions for an immunonephelometric protein assay. This method has been derived for use on the Hyland PDQ (Travenol Laboratories, Thetford, UK) and Kallestad (Kallestad Laboratories Inc, Chaska, Mn, USA) nephelometers. We have also found it applicable to the Behring nephelometer (Hoechst, London, UK). Using this approach, it is possible to establish an assay on these instruments for any serum protein with a concentration above about 10 mg/l for which a suitable antiserum is available. The method has also proved suitable for developing methods for proteins in urine, CSF, saliva, and amniotic fluid. Proteins in urine may be measured at concentrations as low as 1 mg/l.
Automated Enzyme Assay of Antithrombin
Authors: Cederholm-Williams S A
Published: February 2014

The conditions for the automated assay of plasma antithrombin activity over the clinically relevant range of 25–250% using the chromogenic substrate S2238 and the Gilford 3800 enzyme rate analyser are reported.
A Direct Fluoroimmunoassay for Conjugated Chenodeoxycholic Acid Using Antibody Coupling to Magnetisable Particles
Authors: Shridi Farouk A , Chitranukroh A , Pourfarzaneh M , Billing Barbara H , Ekeke G
Published: February 2014

A novel solid phase fluoroimmunoassay for conjugated chenodeoxycholic acid has been developed employing an antiserum coupled to magnetisable cellulose particles and a chenodeoxycholyl glycinefluorescein thiocarbamyl ethylene diamine conjugate as the label. The data obtained from serum samples from 25 patients correlated closely (r = 0·99) with those obtained by radioimmunoassay. The assay is rapid (30 minutes), simple, and ideal for routine clinical purposes.
Reaction Rate Retardation as a Method for Serum Alkaline Phosphatase Isoenzyme Measurement
Authors: Brown Pamela B , Lewis K O
Published: February 2014

A method for serum alkaline phosphatase isoenzymes using an enzyme reaction rate analyser is described. The complete urea-induced degradation of enzyme activity is monitored, from which individual isoenzyme activities are obtained by calculating the constituent exponential components of the degradation curve. Activities have been measured with adequate sensitivity and selectivity for up to four isoenzyme components in normal and in pathological sera. The identity of each isoenzyme present is assigned from its characteristic degradation half-life, and by this method bone and liver alkaline phosphatase are clearly distinguished and quantitated, and a composite value for placental-intestinal alkaline phosphatase activity is obtained. The approach promises to be applicable to a wide range of isoenzymes, and in analogy with ‘reaction rate’ the term ‘reaction rate retardation’ is suggested for the procedure.
Effects of Analytical Error on the Clinical Discrimination of the Urinary 11-Hydroxycorticosteroid Assay
Authors: Levell M J
Published: February 2014

A model consisting of overlapping Gaussian distributions of disease and reference values has been used to calculate the effects of analytical imprecision on the proportions of patients wrongly classified by a test. Using published data the model has been applied to the urinary excretion of 11-hydroxycorticosteroids in the diagnosis of Cushing's syndrome. At the lowest levels of imprecision encountered in hospital laboratories, doubling the imprecision increased false negatives (missed diagnoses) from 3·6 % to 4·1 % and false positives from 9·4 % to 11·2 %. Although improved imprecision may thus produce only marginal improvements of misclassification, there is no level of imprecision below which further improvement does not improve misclassification. It is suggested that the concept of an ‘acceptable level of imprecision’ should be replaced by the concept of costing improvements of imprecision, equating the benefits in terms of patient classification with cost in terms of additional resources.
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.
Who Shall Control the Controllers?
Authors: Jeffcoate S L
Published: February 2014

Many attempts are now being made by external agencies to assess the quality of assay performance in hormone laboratories. Some of the problems associated with this are discussed and some remedies are proposed.
An Evaluation of the First Production Model of the Rank Hilger Chemispek Multichannel Electrolyte Analyser
Authors: Smith M , Little A J , Payne R B
Published: February 2014

The first production model of the Rank Hilger Chemispek multichannel analyser was evaluated. It is a six-channel machine for the analysis of sodium, potassium, chloride, bicarbonate, urea, and creatinine. We chose to run it at 120 samples per hour. The machine was shown to be economical in the volumes of both samples (200 μl) and reagents, flexible, accurate, and precise. Its performance was better than that of other machines with a similar capacity and it is considerably cheaper.
Automated Radioimmunoassay of Total and Free Thyroxine in Human Serum
Authors: Kadury Sana , John Rhys , Woodhead J Stuart , Kurtz Antony B
Published: February 2014

A rapid, automated method for the measurement of total and free thyroxine in serum by radioimmunoassay is described. The method uses a commercially available antiserum covalently coupled to finely divided cellulose. A non-equilibrium reaction provides a very fast procedure: 80 samples can be analysed for total and free thyroxine within 3 hours using the Kemtek 3000 automated immunoassay system. The method also has the advantage that a small sample volume (6·25 μl) is required and that it yields high precision. Serum total and free thyroxine concentrations in healthy euthyroid subjects, pregnant women, and hyperthyroid and hypothyroid patients are reported.
Preparation of Material to Control Precision of Calcium Selective Electrodes
Authors: Fyffe J A , Jenkins A S , Bolland Carol J , Dryburgh Frances J , Gardner Mary D
Published: February 2014

A simple procedure is described for the preparation of a stable precision quality control material for use in the measurement of levels of ionised calcium in serum at or near the reference range. Repeat analyses on a Nova 2 ionised calcium analyser of serum pools stored at different temperatures over a period of three months showed coefficients of variation of less than 4%.
An Assessment of Radioimmunoassay Procedures for Determination of Anti-Acetylcholine Receptor Antibodies in the Sera of Patients with Myasthenia Gravis
Authors: Carter B , Harrison R , Lunt G G , Morris H , Savage-Marengo T , Stephenson F A
Published: February 2014

A reproducible radioimmunoassay procedure for the determination of anti-acetylcholine receptor antibodies in the sera of patients with myasthenia gravis is described and examined in detail. The assay combines features of a number of methods previously outlined and allows repeat determinations of antibody titre in a given myasthenic serum sample with coefficient of variation 6%. The mean ± standard deviation for normal human serum anti-acetylcholine receptor antibodies was found by this procedure to be 0·024 ± 0·033 nmol/l α-bungarotoxin binding sites whereas the range for myasthenic patients was 0–139·14 nmol/l with a mean value of 7·55 nmol/l α-bungarotoxin binding sites.
Changes in Serum Ferritin Levels after Intravenous Iron
Authors: Blunden R W , Lloyd J V , Rudzki Z , Kimber R J
Published: February 2014

The effect of intravenous iron dextran on serum ferritin levels was observed in two patients with iron deficiency anaemia. Serum ferritin levels rose sharply and reached peak levels seven to nine days after infusion when at least 90 % of the infused iron had been removed from the plasma. A linear relation was shown for each patient between the logarithm of the serum ferritin levels and the logarithm of the calculated cellular non-haem iron levels.
Particulate Acetylcholinesterase in Amniotic Fluid and its Implications for Neural Tube Defect Screening
Authors: Webb B , Richardson S J , Garry R , Atkins J
Published: February 2014

Acetylcholinesterase activity in mid-trimester amniotic fluid has been determined by a quantitative spectrophotometric method and a qualitative electrophoretic technique in a limited (76 samples) retrospective study. Differential centrifugation studies on amniotic fluid from normal pregnancies demonstrated the presence of particle-associated acetylcholinesterase sedimenting only at relatively high centrifugal forces. It is postulated that this particle-associated activity was a contributory factor to an observed false-positive incidence of 6·6% when quantitative acetylcholinesterase measurement was used to discriminate between normal pregnancies and those associated with neural tube defects. Discrimination on the basis of electrophoretic analysis of acetylcholinesterase resulted in no misclassification of pregnancies. Particulate acetylcholinesterase would not be expected to influence the interpretation of the electrophoretic pattern due to its size-related exclusion from gel pores. The implication of these observations in the accurate prenatal diagnosis of neural tube defects is discussed.
A Feasible Solvent Separation System for Immunoassays
Authors: Cais Michael , Shimoni Moshe
Published: February 2014

Feasibility is demonstrated for a new solvent extraction method to separate free and bound fractions in hapten immunoassays, without the need to centrifuge. A novel mixer-separator device used in conjunction with solvent extraction makes the new separation method simple and rapid, avoids the need for decantation, and has applications for all mass transfer operations involving solvent extraction.
A Novel System for Mass Transport through Selective Barriers in Non-Centrifugation Immunoassays
Authors: Cais Michael , Shimoni Moshe
Published: February 2014

A new method is demonstrated for the separation of free and bound fractions in a wide range of immunoassays without the need for centrifugation and decantation. The method employs a novel separator device which, in conjunction with any choice of separating reagent, allows all manipulations to be performed in a single tube simply, rapidly, and safely. The system has potential applications in other fields involving mass transport through selective barriers.
Proteinuria after Burn Injury
Authors: Shakespeare Peter G , Coombes Edward J , Hambleton Joan , Furness Diane
Published: February 2014

Qualitative and quantitative aspects of the excretion of protein after burn injury have been investigated. The excretion of total protein and of albumin have been measured nephelometrically while the excretion of proteins of both serum and non-serum origin have been measured by immunoelectrophoresis using antiserum against serum proteins or against a pool of urine from burned patients. Comparison of the patterns of proteins observed in urine using these two different antisera showed the presence of at least three major proteins that did not originate from the plasma. The excretion of two of these three proteins followed closely the pattern of total protein excretion which reached a maximum at five to seven days after injury. The excretion of albumin was greatest in the first 48 hours after injury. Examination of the original burn patients' urine antigen by sodium dodecyl sulphate polyacrylamide gel electrophoresis showed that this urine pool contained greater amounts of lower molecular weight proteins than were observed in a pool of normal urines. The observations suggest that a biphasic renal pathophysiology is observed after burn injury. Initially, there develops a mild transient glomerular lesion which progresses to a different state which shows at least some of the features of a tubular proteinuria.
Value of the Determination of ‘true’ Free Thyroxine in Screening the Newborn with Possible Congenital TBG-Deficiency for Congenital Hypothyroidism
Authors: Looyé A , Van Der Vis-Melsen M J E , Schreuder C H
Published: February 2014

The results of investigations on a family after a screening programme for congenital hypothyroidism are presented. The newborn child and her father appeared to have a congenital thyroxine binding globulin deficiency. Problems regarding standard thyroid hormone tests are discussed. It was observed that the free T4 index as well as a commercial free T4 determination introduced earlier can give misleading results. The first experience with another more promising free T4 determination is also presented.
Assessment of Optimal l-Thyroxine Replacement Dose by the TRH Test
Authors: Squire C R , Gimlette T M D
Published: February 2014

Two hundred patients taking varying l-thyroxine replacement doses were studied using a normal TRH test as the index of optimal replacement dose. The mean optimal dose was 141 μg/day. Normal serum T8 and FT3I were found in most patients, whatever the TRH response, and they are probably too unspecific. Serum T4 and FT4I were elevated in many patients with a normal TRH response. A higher range for FT4I of 102–166, although only 66·5% accurate, gave the best index of optimal l-thyroxine replacement of the single in-vitro tests.
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.
Estimation of the Saturation of Serum Transferrin by an Electrophoretic Technique
Authors: Davy P , Bingham D , Walters G , Whicher J T
Published: February 2014

An electrophoretic method is described for estimating the saturation of serum transferrin. After first precipitating most of the other proteins with Rivanol, the apo-, mono-, and di-ferric transferrins are separated by electrophoresis in urea-polyacrylamide gel. Densitometric scanning enables the percentage saturation to be calculated.
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.
Ultrathinfilm Immunoelectrophoresis
Authors: Michiak Anne , Clark Penelope M S , Kricka Larry J
Published: February 2014

Immunoelectrophoresis (Laurell-rocket) in ultrathinfilm gels has been applied to the determination of human serum albumin in a model study. Agarose gels of 0·24 mm thickness were used and optimum electrophoretic conditions were determined. Precision was assessed and comparison with conventional immunoelectrophoresis and a chemical method was made. Though precision was poor (CV 4–6%) improvements in dispensing small volumes (0·2 μl) should change this. Good correlation between methods (correlation coefficient 0·89–0·97) was obtained. The advantages of the technique are speed of analysis and low reagent costs.
Detection Limits for Protein after Electrophoresis on Cellulose Acetate
Authors: Goodland Frank C
Published: February 2014

The detection limits for protein, when stained with nigrosine after electrophoresis on cellulose acetate, were studied and shown to be: albumin, 3·0 ng; transferrin, 0·8 ng; and Bence-Jones protein, 0·8 ng. This was less than one-hundredth of the previously reported levels. Immuno-fixation, although useful for identification, did not lower the detection limit for Bence-Jones protein.
Prediction of Phenytoin Dosage in Epilepsy Using Multiple Linear Regression
Authors: Gray S P
Published: February 2014

Analysis of plasma phenytoin in a group of patients treated for epilepsy showed that only 36% had values in the therapeutic range. The relationship between plasma phenytoin, body weight, and daily dosage of the drug were explored, and the data were analysed by multiple regression. The resultant equation, relating all three factors, was used to optimise drug dosage, and the importance of using the body weight of the patient before starting a phenytoin regimen is emphasised. An increase in the number of patients with plasma phenytoin in the therapeutic range was achieved, and the clinical value of being in that range is shown.
A Simple Automated Colorimetric Method for Determination of N-Acetyl- β-d-Glucosaminidase
Authors: Moore Joan C , Morris Jacqueline E
Published: February 2014

An automated method for the determination of N-acetyl-β-d-glucosaminidase in serum or plasma using p-nitrophenol ( pNP) N-acetyl-β-d-glucosamine as substrate and a Pye Unicam AURA system is described. Normal samples had activities of 853 ± 146 (SD) nmol pNP liberated/ml/h, with intra-assay coefficient of variation 1·2% and inter-assay coefficient of variation 1·6%. Inhibition of enzyme activity by heparin in plasma samples can be reversed by the addition of calcium chloride to the buffer.
Use of an Enzyme Standard in the Measurement of Enzymes in a Clinicon Reaction Rate Analyser
Authors: Nisbet J A , Owen J A , Pulford F G
Published: February 2014

Measurement of enzyme activity in a Clinicon reaction rate analyser was carried out in two ways: one method was based on absolute calibration and the other used an enzyme standard which involved adjustment of results according to the value for the standard obtained in each batch. Batch calibration significantly improved long-term precision and reduced differences between results obtained in different instruments.
An ELISA Procedure for Detecting Human Anti-Endotoxin Antibodies in Serum
Authors: Gaffin Stephen L , Badsha Nasima , Brock-Utne J G , Vorster B J , Conradie J D
Published: February 2014

We report an ELISA method suitable for the large-scale screening of blood bank stores to identify those blood units containing high concentrations of antiendotoxin antibodies. In Natal, 8·3% of total units collected had antiendotoxin antibodies at concentrations greater than 40 μg/ml, values that may be therapeutically useful. We found that one technician could screen enough samples per year to produce 800 litres of such high-titre plasma.
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.
Value of Serum Glucose Assay as Part of the Biochemical Profile in Screening for Diabetes
Authors: Northam B E , Smith J H , Fitzgerald M G , Nattrass M , Wright A D
Published: February 2014

The value of adding serum glucose assay to the ‘biochemical profile’ was assessed by a detailed follow-up of all inpatients with serum glucose concentrations of 10 mmol/l or more. After excluding patients who were on intravenous glucose infusions or were known to be diabetic. 1 in 10 was found to have unsuspected diabetes by further blood glucose measurements, glucose tolerance tests, and clinical assessment. The incidence was 0·8% of all inpatients receiving a biochemical profile, and in a full year 64 diabetics would be detected. The extra cost of laboratory tests was only £20 for each diabetic detected.
Components of Variance of Some Plasma Constituents in Patients with Myocardial Infarction
Authors: Fraser Callum G , Hearn Craig R
Published: February 2014

Analytical, intra-individual, and inter-individual components of variance were estimated for eight plasma analytes in 20 patients who had myocardial infarction. Replicate analyses were performed on an average of 19·5 specimens obtained from each patient over a four-day period. Analytical variance was >25% of the total variance for sodium, chloride, and bicarbonate levels but ≤12% for potassium, urea, creatinine, calcium, and albumin. Sodium, bicarbonate, urea, and creatinine concentrations showed strong individuality while those of potassium, chloride, calcium, and albumin did not. Estimates of average intra-individual variation were larger than those previously documented; this is probably due to variation in sample collection, transport, and handling. Analytical goals were derived from intra-individual variation but it is not recommended that these be adopted in hospital laboratories.
Fresh Human Blood as the Source of a Regional Quality Survey Programme in Haematology
Authors: Van Gend J M W A
Published: February 2014

In a regional quality survey programme in haematology with a limited number of participants (15 in the region described), it appeared possible to use unpreserved, fresh, EDTA-anticoagulated blood samples. With such samples only the results from hospital laboratories with different instruments and methods could adequately be compared. From the results of single analyses obtained in ten different samples, the systematic differences as well as the precision of the analyses were calculated for each hospital laboratory with respect to haemoglobin, packed cell volume, red blood cell count, white blood cell count, and platelet count.
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.
Development of a Radioimmunoassay for Pregnancy-Associated Plasma Protein A and Establishment of Normal Levels in the First Trimester of Pregnancy
Authors: Anthony F , Masson G M , Wood P J
Published: February 2014

An accelerated double antibody method has been developed for the radioimmunoassay of pregnancy-associated plasma protein A (PAPP-A) in serum. The workable range for the assay was 0·04–1·8 mg/l of serum. PAPP-A levels were determined in single serum samples from 110 women with prospective normal pregnancies of between 7 and 14 weeks' gestation. The level of pregnancy specific β1 glycoprotein (SP1) was also measured in these samples and normal ranges for PAPP-A and SP1 were constructed from the results 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.
Influence of Liver Isoferritin Profile on Quantitative Measurement of Total Ferritin Protein in Human Liver, with Emphasis on Iron Overload
Authors: Zuyderhoudt F M J , Linthorst C , Jörning G G A , Ladiges N C J J , Brugman A M
Published: February 2014

Ferritin was isolated from normal human liver and from iron-loaded human liver by gel chromatography and by ultracentrifugation. From each of these ferritin batches several isoferritin fractions were isolated by preparative isoelectric focusing. It was our aim to have at our disposal isoferritin fractions with relatively large pI ranges but distinctly different isoferritin profiles on analytical isoelectric focusing. These fractions were compared for their immunoreactivity. The total protein in the isoferritin fractions was measured by the nitrogen content. The immunoreactivity of the isoferritin fractions was measured as the ratio of the reaction in immunoassays to the nitrogen content of these fractions. We used radial immunodiffusion and enzyme-linked immunoassay to measure immunoreactivity. The immunoreactivity did not change obviously with the isoferritin composition of the isolated fractions. It is concluded that pathological changes in the isoferritin composition that might occur in liver ferritin during iron overload does not significantly influence the quantitative measurement of liver ferritin protein by immunological methods.
A Simple, Inexpensive Quality Control Material for Ortho ELT-8 Platelet Counts
Authors: Lombarts A J P F
Published: February 2014

Dilutions of 1: 600 and 1: 3000 of 1 μm diameter polystyrene latex suspensions are simple, inexpensive materials for quality control of Ortho ELT-8 platelet counts. The coefficient of variation (CV) for a 12-week period at the 350 × 109/1 level was 2·2%, comparable with that of a commercial control. The CV at the 70 × 109/1 level was 3·5%.
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.
Optical Methods for Monitoring Temperature in Spectrophotometric Analysers
Authors: O'Leary Thomas D , Badenoch Jane L , Bais Renze
Published: February 2014

A procedure is described for monitoring the temperature in the reaction cuvettes of analytical systems that use photometers. The method employs the temperature-dependent change in absorbance of solutions of either 3,5-dinitrosalicylic acid or cresol red. The procedure is simple to perform and is especially useful in monitoring the temperature in instruments such as centrifugal analysers where the reaction cuvette is inaccessible. In some of the instruments studied, methodological changes were required to ensure that reactions were carried out at the selected temperature.
Use of Lucifer Yellow VS as a Label in Fluorescent Immunoassays Illustrated by the Determination of Albumin in Serum
Authors: Bailey M Philip , Rocks Bernard F , Riley Clifford
Published: February 2014

The use of a new label for fluoroimmunoassay is described. Lucifer yellow VS is a highly fluorescent vinyl sulphone dye which, under mild conditions, forms covalent bonds with amino and sulphydryl groups but is extremely stable in water. A large Stokes shift (110 nm) and an emission maximum at 540 nm give Lucifer yellow further advantages over the more commonly used labels. The use of the dye as a label has been demonstrated by developing a heterogeneous fluoroimmunoassay for human serum albumin. The fluoroimmunoassay gave comparable results to those obtained using a less specific colorimetric dye-binding assay (r = 0·97, n = 20). The advantages, limitations, and other potential uses of Lucifer yellow are discussed.
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.
Kinetics of the Antigen: Antibody Reaction
Authors: Deverill I , Lock R J
Published: February 2014

Many techniques for the estimation of specific proteins measure light scattered by, or the turbidity of, suspensions of antigen:antibody aggregates formed in fluid-phase reactions. Although the shapes of reaction curves obtained are well documented,1 2 interpretation of the data in relation to the laws of light scattering and the mechanism of the antigen:antibody reaction are poorly described in the literature. Using photon correlation spectroscopy it has been shown that antigen:antibody complexes continue to grow in size even when no further increases in scatter intensity or turbidity are apparent.
Investigation of Hirsutism: Testosterone is Not Enough
Authors: Carter G D , Holland Sharon M , Alaghband-Zadeh J , Rayman G , Dorrington-Ward P , Wise P H
Published: February 2014

SUMMARY In a consecutive series of 41 hirsute women clinically classified as benign androgen excess, only 34% were found to have elevated plasma ‘total’ testosterone (T), 22% having subnormal sex hormone binding globulin (SHBG). When expressed as the ratio T/SHBG (‘free androgen index’), 85% of the patients had values above the normal range. It is concluded that this index is more reliable than total testosterone in assessing androgen status in female patients.
Bromocresol Purple and the Measurement of Albumin
Authors: Hill P G , Wells T N C
Published: February 2014

This study was undertaken to investigate the extent of the reported discrepancy between serum and plasma albumin concentrations measured by the bromocresol purple (BCP) method. We have shown that plasma albumin concentrations are falsely increased by turbidity due to the precipitation of fibrinogen when plasma is diluted into the BCP reagent. Modification of the BCP buffer (to 0·1M acetate containing 0·15M NaCl, pH 5·5) eliminates the turbidity and thus permits the measurement of albumin in either serum or plasma. Plasma albumin concentrations measured with the modified BCP reagent show excellent correlation with results by an immunoturbidimetric method.