bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Monoclonal Antibody-Based Immunoradiometric Assay for h-LH
Authors: Hunter W M , Bennie J G , Kellett H A , Micklem L R , Scott A , James K 
Published: February 2014

An immunoradiometric assay (IRMA) for h-LH based upon an 125I-labelled mouse monoclonal antibody (MAb) to h-LH with an effective equilibrium constant of 5·8 × 109 l/mol is described. A total incubation time of 3 h at room temperature was required, separation by means of the sucrose layering procedure took a further 1 h and counting times were 1 min/tube. Using the first IRP for h-LH (prep. 68/40) as standard, the detection limit was 0·1 U/l serum and the within-assay CV for duplicate determinations was <10% over the range 1–280 U/l and <3% at 10–100 U/l. The epitope, with which the MAb reacted, shared structures, on the α- and β-subunits of LH since the assay responded to the intact hormone, but not to either of the subunits. Specificity was > 100 000:1 for h-LH vs. h-FSH and > 10 000:1 for h-LH vs. h-TSH. h-CG and h-LH were approximately equipotent. The results on 604 unselected samples were generally very similar to those found by RIA except at levels below 2 U/l for which the IRMA regularly gave lower results suggesting relative freedom from non-specific serum effects. The new assay, based upon potentially limitless supplies of a very stable reagent offers advantages of speed, sensitivity, range, and precision over conventional RIA. The specificity appears to be excellent. Although there are marginally more steps the total staff involvement is less than with conventional methods employing centrifugation.
The Measurement of Urinary LH, by a Solid-Phase Chemiluminescence Immunoassay
Authors: Brockelbank J L , Kim J B , Barnard G J , Collins W P , Gaier B , Kohen F 
Published: February 2014

Ovulation in women may be predicted or detected by a simple, solid-phase, chemiluminescence immunoassay for the measurement of urinary LH. An IgG fraction of a donkey antiserum to rabbit immunoglobulins is passively adsorbed to the walls of polystyrene tubes. Human chorionic gonadotrophin-succinyl-butyl-ethyl-isoluminol and a primary antibody (rabbit anti-human LH) is incubated with samples of early morning urine. After the binding reaction, the solution is removed by aspiration. The antibody-bound fraction is washed twice with buffer. Sodium hydroxide is added and the mixture incubated. After cooling, luminescence is initiated by oxidation of the label with microperoxidase/hydrogen peroxide and the signal integrated. The method has been evaluated in terms of sensitivity, within- and between-batch precision, bias and parallelism. The time interval between the peak day of LH in EMU and maximum follicular diameter during 38 menstrual cycles was −24 h (11%), 0 h (50%), + 24 h (28%) and + 48 h (11%).
Measurement of Copper, Zinc and Magnesium in Serum and Urine by DC Plasma Emission Spectrometry
Authors: Roberts N B , Fairclough D , McLoughlin S , Taylor W H 
Published: February 2014

The application of a DC plasma emission spectrometer to the measurement of copper, zinc and magnesium in serum and urine is reported. Each assay requires only a simple dilution in 1% nitric acid. Comparisons with standard atomic absorption techniques showed good analytical agreement, especially for copper and magnesium. Analysis of quality control preparations for copper and zinc gave results ranging from −1·5% to +3·6% of the stated values for five copper and four zinc experiments, with an unexplained result of +7·6% for one zinc experiment. Reference ranges were compiled for serum zinc and urinary copper which agreed closely with those established by atomic absorption and neutron activation analysis. Assays by DC plasma emission are thus precise and reproducible, and simple enough to authenticate the method for use in a clinical laboratory.
Drug Screening: Evaluation of the Toxi-Lab TLC System
Authors: Jarvie D R , Simpson D 
Published: February 2014

An evaluation of a commercial TLC Kit System (Toxi-Lab®) is described. The performance of the system is assessed in the detection of drugs in overdose and in therapy, and is compared with a GC drug screening system. Toxi-Lab performed well in investigating drug overdoses. We found data on metabolite patterns essential for the identification of drugs in urine and for this reason the system performed much better than GC screening in which information on metabolites is limited. In our experience Toxi-Lab screening was not sufficiently sensitive for the detection of commonly prescribed psychiatric drugs taken in therapeutic doses. This system is rapid, versatile and suitable for small laboratories, but is comparatively expensive and some expertise is necessary to interpret results. A major deficiency of the kit is that the identification procedures are designed for the detection of drugs available in the USA and many drugs prescribed in the UK have been omitted.
An Improved Method for Measurement of Common Tricyclic Antidepressant Drugs and their Metabolites Using Normal Phase HPLC
Authors: Blakesley J D , Howse C G , Spencer-Peet J , Wood D C F 
Published: February 2014

A sensitive HPLC method that allows the simultaneous determination of imipramine, amitriptyline and their desmethyl metabolites, using a 10 cm straight silica cartridge column with a mobile phase consisting of 0·004% perchloric acid in methanol is presented. Detection of the eluent is at 210 nm. The drugs are back-extracted from serum, giving both a good recovery and sensitivity of at least 5 μg/L. This method has proved to be extremely robust and reliable, with coefficients of variation around 3% being reported.
Antenatal Detection of Placental Steroid Sulphatase Deficiency by Measurement of Urinary 16α-Hydroxydehydroepiandrosterone Sulphate
Authors: Wilmot R L , Mawson R J , Oakey R E 
Published: February 2014

A simple gas chromatographic technique for the measurement of 16α-hydroxydehydroepiandrosterone sulphate in urine from pregnant women is described. An assessment was made of the effectiveness of the measurement of this oestriol precursor for the antenatal diagnosis of placental steroid sulphatase deficiency. Twenty-two patients whose pregnancies were complicated by subnormal oestrogen excretion for gestation were studied. In nine of these, where placental steroid sulphatase activity was found subsequently in vitro to be normal, the excretion of 16α-hydroxydehydroepiandrosterone sulphate was <27 μmol/24 h. In the remaining 13 patients, in whom postnatal in vitro assay demonstrated absence of placental steroid sulphatase activity, urinary excretion of 16α-hydroxydehydroepiandrosterone sulphate was 59–360 μmol/24 h. The excretion of this metabolite was below the limit of detection (20 μmol/24 h) in 30 uncomplicated pregnancies. It is concluded that urinary excretion of 16α-hydroxydehydroepiandrosterone sulphate >50 μmol/day or a ratio of urinary 16α-hydroxydehydroepiandrosterone sulphate to urinary oestrogen >2·0 correctly identifies, before delivery, those pregnancies in which fetus and placenta are deficient in steroid sulphatase activity.
A Simple Enzymic Method for the Measurement of Magnesium in Serum and Urine on a Centrifugal Analyser
Authors: Tsang W M , Howell M J , Miller A L 
Published: February 2014

A method is described based on a reaction that requires magnesium-ATP as a co-factor for the activity of hexokinase (HK), coupled with glucose 6-phosphate dehydrogenase (G6PDH). Glucose and NADP are converted to D-gluconolactone 6-phosphate and NADPH, respectively. The rate of increase in absorbance at 340 nm due to the formation of NADPH is proportional to the magnesium concentration in the sample. Magnesium levels in serum and urine measured by the enzymic method compared well with those obtained by atomic absorpton spectrometry. The within-batch precisions were 1·4% and 1·5% for the enzymic method and the atomic absorption method, respectively for a quality assurance sample with a magnesium concentration of 2 mmol/L. The enzymic method is accurate (recoveries of added magnesium to serum samples are 101–102%), reproducible (between batch CV 2·8%), and rapid (23 samples may be measured in 10 min). Data on accuracy, precision and correlation for the enzymic and atomic absorption methods are presented.
Radioimmunoassay for 6-Sulphatoxymelatonin in Urine Using an Iodinated Tracer
Authors: Aldhous Margaret E , Arendt Josephine 
Published: February 2014

A radioimmunoassay (RIA) for urinary 6-sulphatoxymelatonin (aMT6s) using an 125I-aMT6s tracer is described. Iodinated aMT6s used as the label was synthesised by direct iodination of aMT6s using 1,3,4,6 tetrachloro 3,6 diphenylglycouril as the oxidant. The assay shows low cross reactivity with related compounds. Serial dilutions of 1:250 and 1:125 diluted urine gave parallel displacement curves. Comparison of the new RIA using 125I-aMT6s with the RIA using 3H-aMT6s label gave good correlation, as did comparison with a gas chromatography mass spectroscopy (GCMS) for total free and conjugated 6-hydroxymelatonin.
Small Scale Sandwich Enzyme Immunoassay for Human Chorionic Gonadotropin Using a New Micro-Transferable Plastic Bead as Solid Phase
Authors: Ruan Ke-He , Ke Dan-Ru 
Published: February 2014

This paper describes a highly sensitive small scale enzyme immunoassay for human chorionic gonadotropin (hCG) in pregnancy urine using a micro-transferable plastic bead (MTPB) as solid phase. Results of the present method for determination of 40 samples of pregnancy urine correlated well with those of the commercial radioimmunoassay and a better precision was achieved. This solid phase method may be widely applied to the immunoassay of small volumes.
Urinary Excretion of HMMA in Children
Authors: Walters E G , Proctor D G , Elder G H , Walters G 
Published: February 2014

In two centres urinary excretion of HMMA was measured in a total of 359 children, aged from birth to 17 years, who were suspected of having a neuroblastoma; the diagnosis was subsequently confirmed in 39. Measurements were made on 24 h urine samples in 246 children, and on random samples in a further 113. The urinary excretion of HMMA relative to creatinine declined progressively with increasing age. After the age of four years the rate of decline was such that some age groups could be combined for statistical analysis. The range of values for each group was similar whether 24 h or random urine collections were used. It is concluded that the latter are adequate for the initial assessment of HMMA excretion.
A Bloodspot Androstenedione Assay Suitable for Home-Monitoring of Steroid Replacement Therapy in Congenital Adrenal Hyperplasia
Authors: Egan Sandra M , Betts P , Thomson S , Wallace A M , Wood P J 
Published: February 2014

A bloodspot assay has been developed using an antiserum raised against androstenedione-3-carboxymethyloxime-bovine serum albumin (AD-3CMO-BSA) conjugate and 125I-AD-3CMO-histamine tracer. The method has a detection limit of 0·6 nmol/L blood and a working range from 0·6 to 40 nmol/L blood. The between-batch precision ranged from 8·4% to 23·3%. Bloodspot androstenedione (AD) concentrations were measured in 50 neonates (26 male, 24 female) and in 95 children (54 male, 41 female) aged 6 months to 18 years. No sex difference in concentrations was found in neonates, in pre-pubertal children up to 8 years of age, in pubertal children (males 8–16 years, females 8–14 years) or post-puberty. Bloodspot AD concentrations ranged from <0·6 to 2·7 nmol/L in neonates, <0·6 nmol/L in pre-pubertal children, 0·6–2·1 nmol/L in pubertal children and < 0·6–4·6 nmol/L post-puberty. Daytime bloodspot profiles in 10 children on replacement therapy for congenital adrenal hyperplasia generally showed good correlation between 17α-hydroxyprogesterone and AD concentrations ( r = 0·928, P < 0·001). Bloodspot AD profiles have advantages over 17α-hydroxyprogesterone profiles for the assessment of the adequacy of glucocorticoid replacement therapy.
Total Amylase and Pancreatic Isoamylase in Serum and Urine: Considerations from Data on Biological Variation
Authors: Cummings Steven T , Fraser Callum G 
Published: February 2014

The analytical, within-subject and between-subject components of variation were estimated for amylase activity and pancreatic isoamylase activity in serum measured using newer analytical methods. Desirable analytical imprecisions based on within-subject variation were CV ≤ 4·4% and CV ≤ 7·0%, respectively. Conventional population-based reference intervals were not useful because of marked individuality; clinical decision-making points should be derived from the desired sensitivity and specificity. Serial results must change more than about 30% and 40% respectively before significance (P ≤ 0·05) can be claimed. Similar data on total amylase and pancreatic isoamylase activities in random and first morning urines showed that the use of conventional reference intervals was appropriate. Very large changes (> 100%) were required before a difference in serial results was significant. Calculation of the urine amylase/creatinine ratio appeared to confer no advantage. Derivation of the ratio of pancreatic isoamylase to total amylase activity in serum or urine was unlikely to provide additional information of value in either diagnosis or monitoring.
Erythrocyte Membrane Stearic Acid : Oleic Acid Ratios in Colorectal Cancer Using Tube Capillary Column Gas Liquid Chromatography
Authors: Neoptolemos J P , Thomas B S 
Published: February 2014

Erythrocyte fatty acids were measured in 32 patients with colorectal cancer (four with recurrent disease), four patients with large colorectal adenomas, and 42 hospitalised patients without cancer. No significant differences were found with respect to any of the fatty acids between these groups. In particular there was no difference between the erythrocyte stearic acid : oleic acid ratios (mean ± SD) between the cancer cases (1·07 ± 0·31) and the control cases (1·09 ± 0·31, 2-tailed Mann-Whitney U test). No difference in this ratio was observed with respect to age or sex and in the case of colorectal cancer, to the Dukes' stage, degree of tumour differentiation, or recurrence. A significant correlation was found between stearic acid concentrations in plasma and erythrocytes from fasting invididuals ( r = 0·477, n = 24, P < 0·05). This study provides further evidence that the erythrocyte stearic acid : oleic acid ratio is of no value for diagnosing primary or recurrent colorectal cancer.
Changes in Size and Zinc Protoporphyrin/Haemoglobin Ratio in Red Cells of Infants during the First Months of Life
Authors: Bartels P C , Helleman P W , Soons J B J 
Published: February 2014

A longitudinal investigation of changes in red blood cell (RBC) size distribution and zinc protoporphyrin/haemoglobin (ZPP/Hb) ratio was performed. In the course of the first few weeks after birth RBC size distribution histograms show a loss of macrocytic RBCs demonstrated by a rapid decrease of the fraction of macrocytes, whereas the degree of RBC volume dispersion decreases simultaneously. Within this period a significant change in the fraction of microcytes was not observed. At about 6 months of age, a marked shift of RBC size distribution histograms towards lower volumes occurs. Concomitant with the lower MCV values, the values for the absolute distribution width at half peak height (ADW0.5) also showed an obvious decrease. At birth, ZPP/Hb ratios are about three times higher than those of adult subjects and decrease slowly during infancy. This suggests that iron deficiency is unlikely in the first months of life.
Basal Serum Dehydroepiandrosterone Sulphate Concentration Does Not Predict the Cortisol Response to Provocative Testing
Authors: Littley M D , Pollock A , Kane J , Shalet S M 
Published: February 2014

The concentration of dehydroepiandrosterone sulphate (DHEAS) was measured in the plasma of 104 patients aged 16–78 years (48 men) undergoing routine assessment of anterior pituitary reserve. A fasting plasma sample was collected at 0900 h on the same day that either an insulin tolerance test or a glucagon stimulation test was performed. Serum cortisol, DHEAS and prolactin were measured by radioimmunoassay. DHEAS levels between 0·5 and 14 nmol/L were significantly but negatively correlated with age but there was no significant correlation with basal cortisol, maximum stimulated cortisol, the increment in cortisol or basal prolactin. The correlation of DHEAS with age was also observed when results for women were analysed separately but this did not hold for men. For male and female results separately, there was again no correlation of basal DHEAS with basal cortisol, maximum stimulated cortisol, increment of cortisol or basal prolactin. The age and sex related reference range and other factors affecting basal DHEAS concentration make it a cumbersome and unreliable measure of hypothalamic-pituitary-adrenal axis reserve.
A Review of the Role of Established Tumour Markers
Authors: Beastall G H , Cook B , Rustin G J S , Jennings J 
Published: February 2014

Increasing numbers of commercial assays for the established tumour markers are available which are capable of excellent analytical performance. Whilst all these assays are useful as research tools, their clinical value is more limited and should be appreciated before any decision is taken to offer a tumour marker assay service. Calcitonin (medullary carcinoma of thyroid), alphafetoprotein (hepatoma) and human chorionic gonadotrophin (choriocarcinoma) are the only tumour markers that can be used for screening for malignancy in high risk populations. Hormones, paraproteins, alphafetoprotein, human chorionic gonadotrophin and prostate specific antigen are valuable in establishing the diagnosis of certain tumour types. Alphafetoprotein and human chorionic gonadotrophin concentrations at the time of diagnosis are of value in predicting prognosis in specific tumour types. Although their sensitivity for a particular tumour type may be poor, most tumour markers can be used for monitoring the therapy and follow-up of selected marker positive patients. Optimal clinical results of the management of patients with malignancy are usually obtained by specialist centres, and laboratory tumour marker services should be established so that they are appropriate to local oncology specialities.
The Clinical Utility of a Non-Isotopic Two-Step Assay (DELFIA) and an Analogue Radioimmunoassay (SimulTRAC) for Free Thyroxine Compared
Authors: Beckett G J , Wilkinson E , Rae P W H , Gow S , Wu P S-C , Toft A D 
Published: February 2014

The analytical and diagnostic performance of a new non-isotopic, two-step immunoassay (DELFIA) for the measurement of free thyroxine (free T4) in plasma or serum has been compared with an established second generation analogue radioimmunoassay (SimulTRAC). Both methods had a good diagnostic specificity in pregnancy, thyroid clinic patients, and patients taking anticonvulsant drugs. In patients presenting to a general medical ward the diagnostic specificity of both methods was poor. Two samples appeared to contain substances which produced assay interference by DELFIA but not by SimulTRAC assays. When free T4 was measured by equilibrium dialysis a clear association between sample dilution and free T4 concentration was demonstrated in sick euthyroid patients. In contrast, using samples obtained from patients with known thyroid disease, free T4 was little influenced by sample dilution. The effects of sample dilution on free T4 measured by DELFIA were similar to those found using equilibrium dialysis. It would appear that free T4 measurements have a relatively poor diagnostic specificity in non-thyroidal illness irrespective of the method used.
Analytical Goals for Interference
Authors: Fuentes-Arderiu Xavier , Fraser Callum G 
Published: February 2014

Objective analytical goals for interference in clinical biochemical methods have not yet been advocated. We propose that, since total analytical error is ideally less than half the within-subject biological coefficient of variation (CV1), the maximum allowable systematic error produced by an interferent ( I) is: where CVA is the relevant experimental analytical imprecision and SE is the systematic error. Such a goal may be applicable also to non-specificity, matrix effects and carryover.
Determination of Kappa and Lambda Light Chains in Serum Immunoglobulins G, A and M
Authors: Haraldsson Á , Kock-Jansen M J H , Jaminon M , v Eck-Arts P B J M , de Boo T , Weemaes C M R , Bakkeren J A J M 
Published: February 2014

An enzyme-linked immunosorbent assay is described for measuring x and λ light chains within each of the serum immunoglobulin classes G, A and M. The detection limit was 0 · 06 U/L for total IgG, IgG x and IgG λ, 0 · 2 U/L for total IgA, IgA x and IgA λ and 0 · 5 U/L for total IgM, IgM x and IgM λ. The concentrations of x plus λ light chains from the three different immunoglobulins correlated well within those of total immunoglobulin G, A and M as measured by enzyme-linked immunosorbent assay or by immunonephelometry. Adult values for the x/λ light chain ratio were found to be 2 · 0 for IgG x/λ, 1 · 1 for IgA x/λ and 1 · 7 for IgM x/λ.
Quantitative Turbidimetric Assay for Determining Myoglobin Evaluated
Authors: Delanghe Joris , Chapelle Jean-Paul , El Allaf Magdeleine , De Buyzere Marc 
Published: February 2014

A recently introduced turbidimetric immunoassay using shell/core particles for determination of myoglobin (Turbiquant Myoglobin, Behringwerke, Marburg, Germany) was evaluated on the Behring Turbitimer analyzer. Intra-assay CV varied between 1 · 0% and 3 · 2%; interassay CV was between 2 · 0% and 3 · 6%. Linear results were obtained between 2 · 8 nmol/L and 36 · 7 nmol/L. Manual dilution in saline solution allowed measurement of myoglobin concentrations up to 25 400 nmol/L. In the tested range, no high-dose ‘hook’ effect was observed. Haemolysis interfered with the assay when haemoglobin concentrations exceeded 2 g/L. The occurrence of error codes due to the presence of triglycerides was shown to depend on particle size. Repeat assays on diluted samples were necessary at triglyceride concentrations of 2 · 3 mmol/L for post-prandial chylomicrons (200–1000 nm), and at 11–31 mmol/L for very-low density lipoprotein-triglycerides (80–200 nm). No significant interferences of haptoglobin, bilirubin, iodine containing contrast media, and rheumatoid factors were detected for the assay. Treatment of lipaemic samples with Lipoclean (Behringwerke) resulted in lower myoglobin values. Simultaneously drawn serum and heparin-plasma samples gave comparable myoglobin results. However, values obtained in EDTA- or citrate-treated plasma samples occasionally differed significantly from serum values. The upper reference limit for myoglobin concentration was 4 · 2 nmol/L. The turbidimetric assay correlated well with a radioimmunoassay (Byk-Sangtec; r = 0 · 892) and with the automated nephelometric assay (Behringwerke; r = 0 · 944). Values obtained by turbidimetry were comparable to those obtained by the latex agglutination test (Behringwerke).