bluuebunny/crossref_metadata_2025 huggingface dataset:
Circulating C-Peptide: Measurement and Clinical Application
Authors: Ashby J Peter , Frier Brian M
Published: February 2014

Pancreatic beta-cell function is usually assessed by the measurement of plasma insulin concentration in various clinical situations. However, the advent of an assay for the measurement of connecting-peptide (C-peptide) concentration in plasma has provided a further method for the assessment of the secretory capacity of the pancreatic beta cell in clinical disorders, particularly in the investigation of hypoglycaemia. The metabolism and immunoassay methodology of C-peptide are reviewed, and its application in clinical practice is outlined.
Effect of Drinking on Correlations between Biochemical Variables
Authors: Whitfield J B , Allen J K , Adena M A , Hensley W J
Published: February 2014

Several clinical laboratory tests correlate with alcohol consumption, for example, the plasma activities of gamma-glutamyl transpeptidase (GGT) and aspartate aminotransferase (AST), the concentrations of triglycerides (TG) and uric acid (UA) and the erythrocyte mean corpuscular volume (MCV). The correlations of these test results with each other have been studied in a population of men attending a multiphasic health-screening centre. The patterns of correlation were of two types: those between the pairs of variables GGT/TG, GGT/UA, TG/AST, and TG/UA were all unchanged as the level of alcohol consumption increased; the pairs of variables GGT/MCV, UA/AST, AST/MCV, UA/MCV, and GGT/AST all became more highly correlated as the level of alcohol consumption increased.
Free-Radical Oxidation (Peroxidation) Products in Plasma in Normal and Abnormal Pregnancy
Authors: Wickens D , Wilkins M H , Lunec J , Ball G , Dormandy T L
Published: February 2014

Using recently developed methods for measuring free-radical oxidation products in biological material, plasma extracts were studied in 24 women in the first two trimesters of pregnancy, in 124 women in the third trimester of pregnancy, in 20 women with pre-eclamptic toxaemia (PET), and in a control group. There was a significant progressive rise of two groups of free-radical oxidation products throughout pregnancy and a significantly greater rise in PET. In women whose diastolic blood pressure rose to above 70 mmHg there was a highly significant relation between two groups of free-radical reaction products and blood pressure.
Radioimmunoassay of Oestriol in the Urine of Non-Pregnant Women
Authors: Morris Raymond
Published: February 2014

A radioimmunoassay for oestriol in the urine of non-pregnant women is described. Urine is hydrolysed rapidly at room temperature with an E. coli glucuronidase preparation and extracted prior to a simple radioimmunoassay procedure. An antiserum raised against oestriol-6-(O-carboxymethyl) oxime bovine serum albumin is used with (3H)-oestriol as tracer. Free and antibody-bound fractions are separated by partition between ammonium sulphate solution and scintillant without centrifugation. The accuracy and precision of the assay are satisfactory. It gave values approximately 80% of those obtained for total oestrogens by a fluorimetric method.
A Computer-Based Laboratory Record System in an Endocrinology Laboratory
Authors: Mosley J
Published: February 2014

A computer-based system for maintaining cumulative laboratory result records is described. The system is also intended to help in the organisation of laboratory work schedules. The system has been in use for over a year and has proved to be successful in improving the service offered by the laboratory.
Assay of Glycosylated Haemoglobin Using Agar Electrophoresis
Authors: Thornton Waynne E , Schellekens Andries P M , Sanders Gerard T B
Published: February 2014

A fast electrophoretic method for measuring glycosylated haemoglobin (HbA1) is described. Eight samples per cell can be assayed in a single run. Results are compatible with those found by macro-column cation-exchange chromatography; precision is good. The practical shortcomings of the commercially ready-made mini-column chromatographic procedures are not seen using this method.
Diagnosis of Gamma Heavy-Chain Disease
Authors: Albutt Eileen C , Hawker P C , Hine K R , Northam B E
Published: February 2014

The diagnosis of gamma heavy-chain disease can be made only by immunochemical analysis of serum and urine. The case reported here demonstrates the importance of diligent observation of routine electrophoretic patterns, followed by immunoelectrophoresis where indicated for the identification of abnormal bands.
Concentration of Serum Thyroid Hormone Binding Proteins after 131I Treatment of Hyperthyroidism
Authors: Harrop John S , Hopton Malcolm R , Lazarus John H
Published: February 2014

Serum concentrations of the thyroid hormone binding proteins, thyroxine binding globulin, prealbumin, and albumin were determined in 30 thyrotoxic patients before and after 131I treatment. Each patient was placed into one of three groups according to response to treatment. The serum concentration of all three proteins rose significantly in 10 patients who became euthyroid, and a greater increase was seen in 10 patients who developed hypothyroidism. There was no significant change in thyroid hormone binding protein concentrations in 10 subjects who remained hyperthyroid. Changes in the concentration of thyroid hormone binding proteins should be borne in mind when total thyroid hormone concentrations are used to monitor the progress of patients receiving treatment for hyperthyroidism.
Gentamicin Assay: Comparison of an Adapted EMIT Method and an RIA Method
Authors: Dols Jan L S , Van Zanten Anton P
Published: February 2014

The EMIT technique for gentamicin assay adapted to the Centrifichem-300 system was compared with an established RIA procedure. EMIT results correlated very well with the results obtained by the RIA method (r =0·976, N=48).

For the adapted EMIT assay, the interassay coefficient of variation was 4–8 % and for the RIA method 6–14%. Several possible interfering agents were investigated, of which only carbenicillin showed interference in both assays.

Our data indicate that the EMIT technique exhibits adequate precision and accuracy for routine gentamicin determinations.
A Chromatographic Method for Measuring Haemoglobin A1: Comparison with Two Commercial Kits
Authors: Arnqvist Hans , Cederblad Gitten , Hermansson Göran , Ludvigsson Johnny , Wettre Staffan
Published: February 2014

A modified chromatographic method for the separation of haemoglobin A1 is described. Its use for the estimation of the concentrations of the fractions is compared with those of two commercial kits.
Simple Filter Paper Method for Home Monitoring of Blood Glucose, Lactate, and 3-Hydroxybutyrate
Authors: Burrin Jacqueline M , Worth R , Law Susan , Alberti K G M M
Published: February 2014

Previous methods for assessing the control of diabetes at home have concentrated on the measurement of glucose concentrations in urine and, more recently, blood. These levels reflect only one aspect of deranged metabolism in the disease. A technique is described whereby glucose, lactate, and 3-hydroxybutyrate can be measured in capillary blood samples dried on boric acid impregnated filter paper. The technique is sufficiently sensitive to measure 0·05 mmol/l glucose, 0·02 mmol/l lactate, and 0·004 mmol/l 3-hydroxybutyrate with precisions of 4·0%, 4·5%, and 8·0%, respectively. This method could prove useful in the broader metabolic assessment of the diabetic state.
Evaluation of a Commercial Enzyme Immunoassay Kit for Serum Carcinoembryonic Antigen
Authors: Fabricatorian Dickran , Gallagher Neil D
Published: February 2014

An enzyme immunoassay kit for carcinoembryonic antigen (CEA) that uses plastic beads coated with guinea-pig anti-CEA as first antibody and goat anti-CEA conjugated with horseradish peroxidase as second antibody has been evaluated. The method does not involve perchloric acid extraction and therefore avoids a dialysis procedure. It is accurate, sensitive, and inexpensive to operate, and provides values comparable to those obtained with the Roche-CEA Z-Gel radioimmunoassay.
Influence of Antisera, Purification Procedures, and Tracers on Validity of a Testosterone Radioimmunoassay
Authors: De Gomez Myriam S , Frei A , Vitins P , Cekan S Z
Published: February 2014

The levels of testosterone in pooled plasma from men and from women were measured by radioimmunoassay. Testosterone was isolated from plasma either by ether extraction (direct procedure) or by chromatography of the ether extract (chromatographic procedure). Three different antisera (all raised against testosterone-3-oxime albumin) were employed. An additional variable was the use of two tracers, [3H] testosterone and [125I] histamine testosterone. The latter tracer was employed in both a freshly prepared form and two months after labelling. The old tracer was used both in a nonpurified and repurified form.

The results were compared with those given by one of the antisera using the assay with chromatography. The validity of this assay was verified earlier using a test of radiochemical purity. In the statistical evaluation of the data, it was found that the assays of both plasma pools gave the same results as the validated assay, even with two other antisera, but only when the chromatographic purification was used. The direct assays gave significantly increased values for testosterone in the male plasma pool with one antiserum, and in the female plasma pool with all three antisera.

It is concluded that those assays may be considered valid which give results statistically indistinguishable from those obtained by the valid assay. These were all chromatographic assays and, in the man, also two direct assays.

The comparison of [3H] testosterone and [125I] histamine testosterone as tracers did not indicate any major differences in the validity of the assays. When the 125I-tracer was employed, a moderate (1 · 5–2 fold) increase of sensitivity was seen with all three antisera, and the antisera could be used in a 10–40 times higher dilution. Furthermore, it was possible to use [125I] histamine testosterone and obtain practically the same results after two months, whether repurified or not.
An Improved Fully Automated Continuous-Flow System for Immunoassays
Authors: Ismail Adel A A , West Peter M , Goldie David J , Poole Anthony C
Published: February 2014

A modification to the Southmead† continuous-flow automated immunoassay system enables the bound ligand fraction to be quantitated. The bound fraction is sequentially collected, washed, and then eluted from the separating device as a bolus. The misclassification error at separation is of the order of 0.6%, and sample-to-sample interaction is negligible. The application of the modified system to the radioimmunoassay for thyroxine at a rate of 60 samples per hour is described, and satisfactory assay characteristics and performance are documented. The application of the Southmead system to the enzyme immunoassay of thyroxine and to assays for other ligands is discussed.
Loss of A-Apoprotein Immunoreactivity during High-Density Lipoprotein Separation
Authors: Johnson P , Muirhead R A , Deegan T
Published: February 2014

By use of an electroimmunoassay, concentrations of A-apoproteins were estimated in serum and in corresponding apoprotein fractions isolated by ultracentrifugation. These values were compared with high-density lipoprotein concentrations determined by analytical ultracentrifugation. Concentrations of A-apoproteins estimated in serum were considerably higher than in isolated high-density lipoprotein fractions. These discrepancies could not be accounted for entirely by material losses into other fractions during ultracentrifugal fractionation. No comparable differences in apoprotein-B concentrations were observed during the ultracentrifugal separation of low-density lipoprotein. Concentrations of A-apoproteins estimated in the residual serum after precipitation of low-density lipoproteins by heparin and manganous ions were also lower than in the corresponding whole sera. The discrepancies persisted after treatment of serum and isolated fractions with tetramethylurea, urea (9 mol/l), and by heating at 52°C for 3 hours. It is considered that separation by ultracentrifugation induces subtle alterations in the surface structure of the lipoprotein species which give rise to changes in immunoreactivity.
A New Approach to the Costing of Clinical Laboratory Tests
Authors: Broughton P M G , Hogan T C
Published: February 2014

A method of costing clinical laboratory tests is described which avoids the assumptions and omissions of previous methods and overcomes the basic theoretical difficulty of allocating indirect (overhead) costs, which form the major component. The method develops the concept of a ‘cost per request” to cover indirect costs, which reflect the cost of providing laboratory facilities, and a ‘cost per test” to cover the direct analytical costs of the individual tests done. The direct cost per test was found to vary with the workload, which makes it difficult to predict the effect of changes in demand on expenditure. The Canadian Schedule of Unit Values was found to be an unreliable basis for calculating direct labour costs. Examples are given of the direct and indirect costs of consumables, labour, and capital, and their contribution to the total cost of clinical chemistry tests done either during or outside normal working hours. The total annual cost for each analyte may be a more useful indicator of expenditure than the cost per test.
LDH in Gastric Juice and its Limitation in the Diagnosis of Gastric Cancer
Authors: Ibrahim K S , Marrs T C , Husain O A N
Published: February 2014

LDH activity in gastric juice was high in all cases of carcinoma of the stomach investigated provided that the pH of the resting gastric juice was above 5·0. No LDH activity could be detected in gastric aspirate, whether from patients with carcinoma of the stomach or not, when the pH of the resting juice was below 5·0. LDH activity in gastric juice is rapidly and irreversibly inactivated by hydrochloric acid at a pH of 4·5 to 5·0.
A Prospective Assessment of Tests of Fetoplacental Function
Authors: McDowell D R , Oliver R W A , Best F A
Published: February 2014

Biochemical tests have been used to monitor fetoplacental function, mainly to detect impending fetal death in utero. The specimen-sampling patterns employed have not been adequate to detect all fetal deaths, and increasingly these tests have been used to detect low-birthweight babies who are at risk during the perinatal period. The purpose of this study was to investigate the three fetoplacental function tests, namely, serum total oestrogens, human placental lactogen, and cystine aminopeptidase activity under routine conditions to indicate whether these tests detected low-birthweight babies and, particularly, if they aided the clinical assessment of pregnancy.

One hundred and sixty-six patients were studied; each set of results was classified as normal or abnormal and subsequently compared according to the outcome of pregnancy. In addition, a comparison was made between abnormal results where intervention was deemed necessary or unnecessary on clinical grounds. The conclusions reached were that these tests played a minor role in the assessment of pregnancy, at best being used to alert the obstetrician to an increased risk of an ‘abnormal birth.’
Biochemical Differences in Human Glomerular Basement Membrane Related to Diabetes and Age
Authors: De Bats Andre , Rhodes Ellen L , Gordon A H , Parke Dennis V
Published: February 2014

Preparations of glomerular basement membrane from diabetic and young and aged normal subjects have been isolated and purified and the component carbohydrates and amino acids quantitatively determined. Diabetic membrane preparations, compared with membranes from young normal subjects, show significant increases in total hexoses, mannose, and galactose and decreases in sialic acid and glucose; the component amino acids show increases in hydroxylysine, proline, and glycine and decreases in lysine, histidine, and leucine. Basement membrane preparations from aged normals show changes in component carbohydrates and amino acids similar to, but not as great as, those seen in the diabetics.
A Comparison of Three Methods for the Estimation of Capillary Blood Glucose in Filter Paper Spots
Authors: Taylor R P , Pennock C A
Published: February 2014

A comparison has been made between three methods for measuring capillary blood glucose collected on filter paper, including a new method using a Beckman glucose analyser 2. The methods are suitable for use with capillary blood spots collected onto filter paper for monitoring the control of diabetic patients. Their accuracy, precision, and recovery of glucose were similar. Glucose measurement with the Beckman glucose analyser 2 involves elution of the dried blood spots with 2% trichloroacetic acid and injection of a fraction of the eluate into the analyser. The method provides a simple and rapid alternative procedure for laboratories that do not have a heavy workload for this type of assay.
A Reliable Semiautomated Method for the Determination of Total Thiamine in Whole Blood by the Thiochrome Method with High-Performance Liquid Chromatography
Authors: Schrijver Jaap , Speek Andries J , Klosse Jan A , Van Rijn Herman J M , Schreurs Wil H P
Published: February 2014

A sensitive and reliable method for the determination of total thiamine (vitamin B1) in whole blood has been developed which is suited for routine analysis. After extraction, and enzymatic hydrolysis of thiamine phosphate esters, thiamine is separated from interfering compounds by a fully automated high-performance liquid chromatographic (HPLC) system. Thiamine is detected fluorometrically as thiochrome. By calculating the concentration of thiamine on-line with the aid of a computer, it is possible to complete one analysis within four hours. Routine thiamine determinations can be carried out in a series of 120 samples within 48 hours.

The within-assay and between-assay coefficients of variation of the analysis of total thiamine in whole blood were 4·2 and 4·4%, respectively. The between-assay analytical recovery of thiamine diphosphate added to blood samples was 99·9 ± 11·7% (mean ± SD). The HPLC method described has been applied also to the analysis of thiamine in plasma and erythrocytes. In agreement with other reports, it was found that about 80% of total thiamine of whole blood is present in the erythrocytes. Reference values of thiamine in whole blood of the human were found in the range 95–155 nmol/l.
Levels of Adenosine 3′,5′ Cyclic Monophosphate and Guanosine 3′,5′ Cyclic Monophosphate in Single Urine Specimens Collected from a Large Population of Healthy Subjects
Authors: Turner G A , Ellis R D , Guthrie D , Latner A L , Skillen A W , Ross W M
Published: February 2014

The levels of adenosine 3′,5′ cyclic monophosphate and guanosine 3′,5′ cyclic monophosphate have been measured in random urine specimens provided by 95 healthy volunteers with a view to assessing the importance of the effects of certain physiological factors on the cyclic nucleotide levels in this type of specimen, and to establish suitable reference ranges for future patient monitoring studies. Of the factors investigated, only the stage of the menstrual cycle was found to have a significant effect; even this variation was still within the overall normal reference range. Measurements of urine cyclic nucleotides were also made in relation to the method of specimen collection, handling, and storage. From these studies it was concluded that if the specimen is placed in a refrigerator within a few hours of collection and then transferred to a deep-freeze within 48 hours, these factors do not present any major problems for the subsequent assay of the cyclic nucleotides.
Comparison of Amerlex, NML, and Ames Total Thyroxine and Triiodothyronine Radioimmunoassay Kits
Authors: Wilke Timothy J , Turnbull Patricia A
Published: February 2014

An evaluation of the Amerlex system for determination of total thyroxine (T4) and total triiodothyronine (T3) is described. The within- and between-batch precisions were acceptable, and analyses of quality control material and linearity studies demonstrated good accuracy at the clinical decision levels. The correlations obtained with NML and Ames T4 and T3 kit methods were highly significant. The Amerlex T4 and T3 methods are rapid, technically simple, and, coupled with excellent precision and accuracy, present significant advantages.
Use of n-Bromosuccinimide for the Iodination of Proteins for Radioimmunoassay
Authors: Reay Paul
Published: February 2014

A new method, employing the mild oxidant n-bromosuccinimide, for the iodination of proteins for radioimmunoassay is described. Human prolactin, follicle-stimulating, luteinising, thyroid-stimulating, and growth hormones were iodinated with 125I by this method to specific activities up to 136 μCi/μg. Incorporation of iodine ranged from 67% to 83% using 2μg hormone, 200 μCi Na125I, 0·5 nmol oxidant, and a reaction time of 15s. In comparative studies, the immunological activity after iodination by this method was equal to, or greater than, that by the chlorine gas, Iodo-Gen, or chloramine-T methods. The reagent is cheap and stable, and the method permits efficient use of antigen and iodide.
A Regional External Quality Assessment Scheme for Serum Thyroxine-Binding Globulin
Authors: Attwood E C , Atkin G E
Published: February 2014

The results from a Regional External Quality Assessment Scheme for the assay of serum thyroxine binding globulin (TBG) are presented. It has been shown that different methods of analysis (eg, rocket immuno-electrophoresis, radioimmunoassay, and radial immunodiffusion) produce comparable results using a common calibrant. Since there is no commonly agreed universal calibrant for TBG, however, results (in mg/l) for various assay systems with differing methods of calibration show wide variance.
Effect of Favourable Treatment of Samples on Indices of Performance in External Quality Assessment Schemes
Authors: Rumley Alan Geoffrey , Roberts Leslie Barry
Published: February 2014

This study was carried out to examine the effect on performance, as assessed by external quality assessment schemes, of ( a) replicate analysis of external quality assessment samples, and positioning of external quality assessment samples immediately after the calibrants, and ( b) alteration of results on the basis of previous performance in order to bring them closer to the method mean values obtained from all laboratories participating in the external quality assessment scheme. Indices of performance were then compared with those obtained from our normal practice where external quality assessment samples were treated as patient samples. Using these methods we were unable to improve significantly our precision or league ranking based on precision over the six-month period of study. We were able to reduce our bias from method means but at the expense of making precision and league ranking worse.
Minimisation of Salicylate Interference in the Glynn and Kendal Paracetamol Procedure
Authors: Longlands M G , Wiener K
Published: February 2014

The Glynn and Kendal technique for plasma paracetamol assay was investigated in an attempt to eliminate its susceptibility to interference from salicylate. Modification of the nitrating reaction so as to produce milder conditions by omission of hydrochloric acid, reduction of nitrite concentration, and limiting the time of reaction to 2 minutes resulted in far less interference. A further improvement was achieved by reading at 450 nm. The proposed modification reduces the interference from a salicylate concentration of 100 mg/dl to the equivalent paracetamol concentration of 12 mg/l, compared with about 70 mg/l in the unmodified method.
Evaluation of a Quantitative Solid Phase Reagent System for Determination of Blood Analytes
Authors: Thomas Lothar , Plischke Wolfgang , Storz Gunther
Published: February 2014

In the first part of the Seralyzer system evaluation the precision and accuracy was studied with a total of 1245 clinical specimens, various commercial control sera, and pooled human sera. The calculated overall precision (between-run, and within-run) and day-to-day precision (% CV) was found to be within 3·0 to 5·4 for glucose, 2·8 to 7·1 for BUN, 1·5 to 6·2 for uric acid, 5·3 to 7·5 for bilirubin, and 3·2 to 8·6 for LDH. The clinical values are in agreement with values from respective comparative methods, as indicated by the regression statistics. The analysis of Seralyzer accuracy data using quality control sera showed in some cases a between-method difference. Supporting studies simulating additional important clinical situations showed that the clinical values for BUN, glucose, and uric acid of approximately 200 specimens from the emergency ward correlated with the respective comparative method values. In this phase of the study we verified that the instrument calibration was stable for a 24-hour period and that there is no effect of module (test) change on precision of Seralyzer determinations. The intra- and inter-laboratory performance in general practitioners' laboratories could be demonstrated using quality control sera.
A Theoretical Study of Carryover in Discrete and Continuous-Flow Systems
Authors: Dixon K
Published: February 2014

The Broughton equation for carryover constant k contains an assumption. It is shown that a slightly different equation can be derived in which there are no assumptions. A procedure is described whereby knowledge of the carryover constant k can be used to correct analytical results in computer-controlled instruments. In a commercial instrument, use of the wrong correction algorithm can lead to errors of 10% in the carryover correction.
Evaluation of a Simple Colorimetric Assay for Serum Angiotensin-Converting Enzyme: Comparison with a New Ion-Pair Liquid Chromatography-Assisted Assay
Authors: Kwarts Eddy , Beukenveld Gerard , Gazendam Jurjen
Published: February 2014

The development and validation of two different assays for serum angiotensin-converting enzyme are reported. The first step in both analytical systems is based on enzymatic cleavage of the synthetic substrate, hippuryl—histidyl—leucine, under conditions advocated by Cushman and Cheung. The hippuric acid released is then assayed either by colorimetry following an azlactone condensation reaction with an aromatic aldehyde, or by reversed-phase ion-pair high-performance liquid chromatography (HPLC). Both procedures reveal good linearity in the range 0–80 nmol/ml per min, with an inter-assay coefficient of variation of 6·2% for the colorimetric assay and 4·5% for the HPLC-assisted assay. Recovery values measured for the colorimetric method ranged from 97% to 102% and for the HPLC-assisted method from 98% to 101%. The colorimetric method is suitable for performance in small hospital laboratories since it can be carried out with simple analytical instrumentation. It is obvious nevertheless, that the HPLC-assisted assay reveals better validation criteria. The method is also simple and rapid and it has successfully been used in our laboratory for the last two years.
Clinically Significant Effect of Protein Concentration on Ion-Selective Electrode Measurements of Ionised Calcium
Authors: Payne R B
Published: February 2014

Others, using an Orion SS-20 ionised calcium analyser, noted that the ionised calcium concentration of a native serum sample was 8% greater than that of its ultrafiltrate. The experiments described here, using a Nova 2 ionised calcium analyser, confirmed a positive protein interference which was greater for human albumin than for IgG. Uncharged dextran showed no positive interference but dextran sulphate, which is highly charged and binds calcium, showed a large effect. Thus the interference is related to macromolecule charge. Dialysis experiments with normal and pathological human serum samples indicated that the ionised calcium of diffusible plasma water was overestimated by an average of 9 · 6% at an albumin concentration of 40 g/l and by 4 · 8 % at 20 g/l. It is concluded that the measurement of ionised calcium with existing analysers can be clinically misleading in patients with abnormal plasma proteins. Hypocalcaemia is likely to be overdiagnosed and hypercalcaemia underdiagnosed in the presence of hypoalbuminaemia.
Increased Hepatic Iron Stores in the Human Fetus after Maternal Total Dose Infusion of Iron Dextran
Authors: Bauminger B B , Walters G
Published: February 2014

The results are presented of the chemical and histochemical assessment of the hepatic iron stores in two babies stillborn after treatment of iron deficiency in the mother by a total dose infusion of iron dextran. The levels of storage iron in the liver determined by chemical analysis were much higher than in six other stillborn babies whose mothers had not been so treated. This difference was not demonstrable by a histochemical method.
Markers in Breast and Lung Cancer
Authors: Coombes R C , Dearnaley D P , Ellison Morag L , Neville A M
Published: February 2014

We have investigated the role of biochemical markers in breast and lung cancer but have found that currently available tests have little role in management. In breast cancer, for example, we have found that the most sensitive method for routine screening for metastases is by using chest x-ray and clinical examination, liver function tests, and carcinoembryonic antigen measurements. We are now examining other methods for detecting metastases using immunocytochemistry in cytological preparations of bone marrow and attempting to raise monoclonal antibodies to breast cancer cells. In lung cancer, the major effort has been directed towards characterisation of large-molecular-weight ectopic hormones, particularly calcitonin.
Emergency Biochemistry Services—Are They Abused?
Authors: Smith A D Stuart , Shenkin Alan , Dryburgh Frances J , Morgan H Gemmel
Published: February 2014

An out-of-hours emergency biochemistry service, which allows access by all medical practitioners of varying experience within a hospital, can lead to overuse or even abuse of limited and costly facilities. When the workload increases, problems of staffing a voluntary (but paid) working rota may emerge. An industrial dispute involving medical laboratory scientific officers (MLSOs) caused the role of the emergency service to be examined and alternative regulating mechanisms to be tested.

Experience at Glasgow Royal Infirmary between 1974 and 1981 has been reviewed. From 1977 to 1979, when clinicians (usually junior) arranged analyses directly with the MLSOs, test numbers increased by about 26% per annum. This was not associated with any concomitant increase in the range of analyses offered. During a five-week period in 1980, consultant clinicians had to contact a consultant clinical biochemist to arrange all emergency analyses, and test numbers were reduced to 13% of the previous levels. Subsequently, all requests for emergency analyses were made by clinicians to laboratory medical staff, and test numbers fell to approximately 60% of 1979 levels. This requesting system is now firmly established.

Continued vigilance is required to maintain the reduced level of requesting, but too great a limitation on emergency requests may cause less efficient patient management. Senior clinical staff should be encouraged to take greater responsibility for the use of emergency laboratory services.
An Appraisal of the Analytical Significance of Tooth-Lead Measurements as Possible Indices of Environmental Exposure of Children to Lead
Authors: Delves H T , Clayton Barbara E , Carmichael Alexandra , Bubear Michelle , Smith Marjorie
Published: February 2014

The analysis for lead of whole crowns from deciduous incisors has been used as an index of the cumulative exposure to lead of children during the prenatal period and until the time of shedding the tooth. The lead was determined by solvent extraction followed by atomic absorption, and strict analytical quality control was employed. The concentrations of lead in pairs of central and lateral incisors from children revealed unexpectedly large differences for some individuals.
Electrophoretically Determined Haemoglobin A1 Concentrations during Short-Term Changes in Glucose Concentration
Authors: Puukka Raija , Leppilampi Marjatta
Published: February 2014

In our experience, electrophoresis on agar gel is a very satisfactory alternative to the more widely used chromatographic methods for the determination of haemoglobin A1 (HbA1). Like the chromatographic method, the electrophoretic method is unable to detect any difference between the labile intermediate form of HbA1, which changes rapidly with acute changes in blood glucose level, and the more stable end-product, which reflects long-term glucose levels. In vitro at 37°C the electrophoretically determined HbA1 concentration increases with increasing glucose concentration and with time in both normal and diabetic erythrocytes, but decreases to the preincubation concentration during further incubation of the erythrocytes in a glucose-free medium at 37°C. Similarly, if normal or diabetic erythrocytes are incubated with isotonic saline before the HbA1 assay, the labile fraction is eliminated. In diabetics, the decrease in HbA1 concentration correlates with both the blood glucose level and the preincubation HbA1 concentration. Thus for HbA1 to be an accurate indicator of long-term glucose control in diabetic patients saline incubation of the erythrocytes may be necessary before HbA1 assay by the electrophoretic method, otherwise the assay results will also reflect recent changes in the blood glucose level.
Simple and Rapid Method for the Assessment of the Oxygen Affinity of Haemoglobin
Authors: Roberts M J , Cole P V
Published: February 2014

The affinity of haemoglobin for oxygen may be expressed as the oxygen tension at 50 % saturation under standard conditions (P50). A rapid technique for the determination of P50 using a micro-tonometer with pH electrode and oximeter was evaluated. Equilibration time was found to be 15 minutes with no change in PCV, although plasma haemoglobin levels were slightly elevated. Estimation of P50 in blood from 32 non-smokers gave a mean of 26·4 ± 0·9 (SD) mm Hg (3·51 ± 0·12 kPa) with a precision of 0·3 (SD) mm Hg (0·04 kPa). The system was found to be accurate, precise, and simple in operation, allowing up to 16 P50 determinations an hour to be performed with 85 μl blood samples.
Evaluation of Three Commercially Available C-Peptide Kits
Authors: Van Rijn HJM , Hoekstra JBL , Thijssen JHH
Published: February 2014

Three commercially available methods for the determination of C-peptide in human serum were evaluated. All kits were found to be acceptable with respect to precision and analytical recovery, while differences were observed with respect to sensitivity and cross-reactivity to human proinsulin. Furthermore an intermethod comparison was performed. It is pointed out that, before C-peptide determination on serum from insulin-treated diabetic subjects, a PEG precipitation, to remove antibody-bound proinsulin, should be done.
Major Factors Limiting Sensitivity of Sandwich Enzyme Immunoassay for Ferritin, Immunoglobulin E, and Thyroid-Stimulating Hormone
Authors: Ishikawa Eiji , Imagawa Masayoshi , Yoshitake Shinji , Niitsu Yoshiro , Urushizaki Ichiro , Inada Mitsuo , Imura Hiroo , Kanazawa Reizo , Tachibana Seiji , Nakazawa Nobuhiko , Ogawa Hiroshi
Published: February 2014

By using IgG-coated polystyrene balls and β-d-galactosidase-labelled Fab', sandwich enzyme immunoassays for human ferritin, immunoglobulin E (IgE), and thyroid-stimulating hormone (TSH) were developed, and their sensitivities were shown to be largely limited by the purity, binding efficiency, and amount of β-d-galactosidase-labelled Fab' used. (1) Their sensitivities were enhanced 10 to 50-fold by using affinity-purified Fab' labelled with β-d-galactosidase. (2) Their sensitivities depended upon the efficiency of specific binding of the labelled Fab' to antigens adsorbed on antibody IgG-coated polystyrene balls. (3) Their sensitivities were improved by using the minimal amount of labelled Fab' that gave a reliable calibration curve. Under optimal conditions the sensitivities obtained for ferritin, IgE, and TSH were 0·09 pg (0·2 amol), 0·48 pg (2·4 amol, 0·2 mIU), and 3 · 2 mμU (5 · 7 amol) per tube, respectively.
Catecholamine Measurements in Phaeochromocytoma: A Review
Authors: Causon Roger C , Brown Morris J
Published: February 2014

The early diagnosis of phaeochromocytoma by measurement of catecholamines or their metabolites is important, since it brings the prospect of permanent cure to a small but significant proportion of the hypertensive population. The development of sensitive and specific methods for the analysis of catecholamines has led to the increased use of such measurements in the biochemical diagnosis and localisation of this rare tumour.
Temperatures Used in the Determination of Enzyme Activity in Clinical Biochemistry Laboratories in Britain: Results of a Survey
Authors: Fleck A , Colley C M ,   Association of Clinical Biochemists
Published: February 2014

Information on the temperature used in the determination of enzyme activity in clinical biochemistry laboratories in Britain was obtained by circulating a questionnaire to 400 laboratories in Britain. Replies were analysed from 321 laboratories (80%). A large majority of laboratories use 37°C to determine enzyme activity: 99% use this temperature for amylase, 88% for alkaline phosphatase, and 81% for aspartate and alanine amino-transferases.

A greater proportion of laboratories with large workloads use 37°C than do those with smaller workloads. The majority of laboratories use equipment with incubation temperatures that are selectable within the laboratory. When there is evidence of advantage in using a particular temperature most laboratories use this temperature.

Almost one-quarter of the laboratories replying participate in a local agreement to use 37° to determine enzyme activity. About one-third of laboratories consider it impracticable to change to 30°C, and of those replying to the question on whether they were willing to change to 30°C, 49% indicated that they were not willing to do so.
A Ligand-Binding Assay for Thyroxine-Binding Globulin Based on Polyethylene Glycol Separation
Authors: Hall Kate , Laing Ian
Published: February 2014

A simple ligand-binding assay for thyroxine-binding globulin (TBG) is described. The method depends on the partition of labelled thyroxine between bovine serum albumin and TBG. Differentiation between labelled thyroxine bound to TBG and bovine serum albumin is achieved by the addition of excess TBG antiserum and subsequent precipitation with polyethylene glycol. The results are compared with the Corning Immophase kit method for TBG.
Influence of Pyridoxal-5′-Phosphate on Temperature Relationship of Aspartate Aminotransferase and Alanine Aminotransferase
Authors: Hafkenscheid J C M , Van Der Ven-Jongekrijg J , De Boo TH
Published: February 2014

The influence of pyridoxal-5′-phosphate on the temperature relationship of aspartate aminotransferase and alanine aminotransferase has been determined. On varying the reaction temperature from 25° to 45° both enzymes showed small but significant deviations from a linear Arrhenius relationship. Supplementation with pyridoxal-5′-phosphate in general enhanced the catalytic activity to the same degree over the entire temperature range. Our results corroborate the findings of Rej but not those of Jung et al.
N-Acetyl-β-D-Glucosaminidase Levels and the Onset of Diabetic Microangiopathy
Authors: Whiting P H , Ross I S , Borthwick L J
Published: February 2014

N-Acetyl-β-d-glucosaminidase (NAG) levels in serum and urine from diabetics have been measured over a three-year period to assess their potential as indicators of the onset of retinopathy and nephropathy. The presence of retinopathy and nephropathy was confirmed by fluorescein angiography performed at the end of the study and by proteinuria, respectively. Three groups of diabetics were investigated, those on insulin, on oral hypoglycaemics, or on diet only. There was no apparent correlation between total NAG activity in serum with the development of retinopathy, nor were serum isoenzyme variations useful in this context. However, urine total NAG activity demonstrated a striking difference between diabetics of all groups and normals. In particular the B isoenzyme doubled in diabetics. The potential use of this finding in relation to prediction of the onset of microangiopathy is discussed.
Radioimmunoassay of Sodium Cromoglycate in Human Plasma
Authors: Brown Kevan , Gardner John J , Lockley William J S , Preston John R , Wilkinson David J
Published: February 2014

A sensitive radioimmunoassay method for sodium cromoglycate in human plasma is described. The lowest quantifiable concentration of sodium cromoglycate is 0·93 nmol/l when 0·1 ml plasma samples are analysed. Direct analysis of sodium cromoglycate concentrations in plasma samples collected up to several hours after the administration of single therapeutic doses of the compound is possible. An antiserum raised in a sheep, radioligand heterogeneously labelled with iodine-125, and a second antibody technique for the separation of bound and free radioligand are employed. The inter-assay coefficient of variation is less than 14% (n=23). The range of the method is limited; both 0·01 and 0·1 ml volumes of plasma must be analysed to encompass the concentration range 0·93–139 nmol/l which may be encountered in plasma samples from patients and human volunteers. The method is specific for sodium cromoglycate as indicated by a low cross-reactivity of the anti-cromoglycate antiserum with a number of drugs.
Serum Iron and Total Iron-Binding Capacity Determination by Flow-Injection Analysis with Atomic Absorption Detection
Authors: Rocks Bernard F , Sherwood Roy A , Turner Zoe J , Riley Clifford
Published: February 2014

The deproteinised sample (150 μl) is ‘injected’ into a continuously flowing stream of deionised water which is pumped, via a capillary tube, to the nebuliser of an atomic absorption spectrophotometer. Analytical readout is obtained, in the form of transient peaks, 6 s after sample injection.

Before injection traces of haemoglobin are removed from the serum by treatment with trichloroacetic acid-ascorbate solution. This protein precipitant facilitates rapid removal of haemoglobin bound iron without the need for heating. After centrifugation the supernatant solution is introduced into the flowing stream by use of a novel inexpensive ‘injector’.

Analytical recovery and precision are good, and results compare well with those obtained by a standard AutoAnalyzer procedure.
Insulin Resistance and Iron Overload
Authors: Dandona P , Hussain M A M , Varghese Z , Politis D , Flynn D M , Hoffbrand A V
Published: February 2014

Glucose tolerance tests performed in 15 patients (10 males and 5 females, age range 6–34 years, mean 16 years) with transfusional iron overload revealed fasting and subsequent blood glucose concentrations within the normal range in all except one patient who was overtly diabetic. However, in all patients except one, blood glucose concentration at 2 hours was higher than the respective fasting glucose concentration. All but two of the patients (one of whom was diabetic) showed fasting and post glucose hyperinsulinism. All the patients had hepatic dysfunction of varying severity. It is hence suggested that the initial disturbance of carbohydrate metabolism in transfusional siderosis is insulin resistance, similar to that found in chronic liver disease. Overt diabetes is probably a later event, occurring when sufficient damage to pancreatic cells has occurred and appropriate hyperinsulinaemia cannot be sustained.
Genetic Bisalbuminaemia Occurring Together with Myeloma
Authors: Porta F A , Riches Pamela G , Richardson Dorothy , Knox J , Hobbs J R , Fine J M
Published: February 2014

Bisalbuminaemia occurring together with paraproteinaemia in a case of proven myelomatosis is described. The albumin variant was investigated by dye-binding, electrophoresis at pH 5·0, 6·8, and 8·6, and by relative mobility studies compared with known genetically inherited variants. The present variant was indistinguishable from the previously described Pollibauer type.
Development of a Filter Paper Blood Spot Radioimmunoassay for Thyroid Stimulating Hormone Suitable for a Regional Neonatal Screening Unit
Authors: Moore Hilary , McMillan Mary
Published: February 2014

The radioimmunoassay described measures TSH in dried whole blood spots collected from neonates onto filter paper Guthrie cards. Microgranular cellulose is added to the precipitating reagent at the critical separation stage of the assay to overcome imprecision caused by the presence of the filter paper sample disc in the tube. The method was developed for a regional neonatal screening unit and has been found to be very reliable during ten months' routine use. It was required to be as precise, sensitive, accurate, rapid, simple, and inexpensive as possible and suitable for use with automatic diluting equipment in order to process large numbers of samples. Other methods were examined for their suitability and found not to fulfil one or more of the above criteria.
Radioenzymatic Assay of Catecholamines: Reversal of Aluminium Inhibition of Enzymatic O-Methylation by Desferrioxamine
Authors: Mason L , Weinkove C
Published: February 2014

Alumina is commonly used for the purification and concentration of catecholamines in biological specimens before analysis. Acid eluates of alumina, found to contain high concentrations of A13+, interfered with O-methylation but not with N-methylation. The chemistry of the catecholamines, supported by kinetic studies, suggest that complex formation between aluminium and the substrate account for the observed inhibition of O-methylation. The addition of desferrioxamine, a metal-chelating agent, to the reaction mixture reversed this inhibition and, by allowing a preliminary alumina extraction, permits the measurement of low concentrations of catecholamines in biological samples.
Influence of Erythrocytes on Direct Potentiometric Determination of Sodium and Potassium
Authors: Bijster P , Vader H L , Vink C L J
Published: February 2014

We have shown that the sodium concentration in whole blood measured by direct potentiometry is higher than in plasma. The ‘erythrocyte-effect’, already described by Siggaard Andersen, is most pronounced for instruments equipped with a reference electrode with an open static liquid junction and is thus a general phenomenon. Instruments with a modified liquid junction show less interference. The same phenomenon appears for the determination of the potassium concentration, although the difference between whole blood and plasma, when measured with instruments equipped with a modified liquid junction, can be neglected in practice.
A Simple Rapid Method for Determining Theophylline in Serum by HPLC
Authors: Fitzpatrick Joseph , McClelland Malcolm
Published: February 2014

A method for the determination of theophylline in serum using a simple extraction procedure is described. The method is linear to 300 μmol/1, within-batch and between-batch precisions are acceptable, and good recovery of added theophylline is obtained.