bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypercalcaemia Due to Calcium Binding by a Polymeric IgA x-paraprotein
Authors: Pearce C J , Hine T J , Peek K
Published: February 2014

Total serum calcium concentration was raised in a 63-year-old lady with multiple myeloma and markedly elevated serum IgA x-paraprotein concentration. Symptoms of hypercalcaemia were absent, and serum ionized calcium was normal, suggesting calcium binding by the abnormal protein. This was demonstrated directly after isolation of the paraprotein and characterization of the calcium/protein interaction. After reduction of the paraprotein with mercaptoethanol, sodium dodecyl sulphate polyacrylamide gradient gel electrophoresis revealed two bands corresponding to light and heavy chains, but under non-reducing conditions the isolated paraprotein migrated in a series of bands, possibly representing polymeric forms of the basic immunoglobulin moiety.
Immunoreactive Endothelin in Human Kidney
Authors: Morita S , Kitamura K , Yamamoto Y , Eto T , Osada Y , Sumiyoshi A , Koono M , Tanaka K
Published: February 2014

Using a sensitive and specific radioimmunoassay for endothelin, we examined immunoreactive endothelin in human kidney tissue obtained from three necropsy and three nephrectomy cases. Immunoreactive endothelin was present in high concentrations in human kidney inner medulla (necropsy cases: 1 · 08 ± 0 · 47 pg/mg wet weight:mean ± SE)(nephrectomy cases: 2 · 77 ± 0 · 46). Characterization by reverse phase high performance liquid chromatography indicated that the only immunoreactive endothelin in human kidney inner medulla is endothelin-1, although immunoreactive endothelin in rat and pig kidney inner medulla comprises both isopeptides endothelin-1 and −3, suggesting that the genetic expression of endothelin differs according to species.
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.
A Comparison of Commercial Kits for the Measurement of Lipoprotein(a)
Authors: Dagen M M , Packard C J , Shepherd J
Published: February 2014

Five commercial kits for the assay of lipoprotein(a) were investigated and two of these, the Immuno Enzyquick and Biopool TintElize, both enzyme-linked immunoassays, were studied in detail. Whilst there was a strong correlation between the results obtained using the two methods there was a significant difference between the absolute values. In view of its higher precision at low levels and robust performance, the Enzyquick kit (Immuno Ltd) was selected for use in this laboratory.
Purification of Human Pancreatic Lipase and the Influence of Bicarbonate on Lipase Activity
Authors: Iizuka K , Higurashi H , Fujimoto J , Hayashi Y , Yamamoto K , Hiura H
Published: February 2014

Pancreatic lipase was purified from human pancreatic juice by ion exchange chromatography and HPLC molecular sieve chromatography. The molecular weight was measured as 50 Kda by SDS-PAGE, as 47 Kda by HPLC and was calculated as 51 Kda following amino acid analysis. The isoelectric point of the purified lipase was 7 · 4 and maximal enzyme activity occurred at pH 9 · 5 in glycine buffer (0 · 1 mol/L) containing deoxycholate (19 mmol/L), colipase (3 mg/L) and triolein (0 · 3 mmol/L). However, the addition of bicarbonate at a final concentration of 0 · 1 mol/L decreased the pH for maximal enzyme activity and increased the lipase activity significantly. At higher concentrations of bicarbonate the lipase activity decreased. These results suggest that bicarbonate is an important regulator of lipase activity, perhaps related to an effect on the detergent properties of deoxycholate.
Bhattacharya: A New Application for Quality Control
Authors: Oosterhuis W P , Modderman T A , Dinkelaar R B , Zwinderman A H , van der Helm H J
Published: February 2014

The Bhattacharya method and the ‘average of normals’ method for internal quality control were compared. Both are based on unselected patient test results. The Bhattacharya method is mostly used in clinical chemistry for calculation of reference intervals but could be modified for quality control procedures. Using the data of a coagulation test and simulating systematic errors, it was concluded that the Bhattacharya method is more sensitive to expected shifts and is more flexible than the ‘average of normals’ method.
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).
Hormonal Factors Associated with Weight Loss in Patients with Advanced Breast Cancer
Authors: Knapp Martyn L , Al-Sheibani Said , Riches Pamela G , Hanham Ian W F , Phillips Robert H
Published: February 2014

Fasting blood samples were collected from 83 patients with histologically proven breast cancer and analysed for plasma glucagon, serum immunoreactive tumour necrosis factor (TNFα), insulin, glucose, growth hormone, Cortisol and TSH. Samples from patients with known diabetes mellitus or thyroid disease, and those on parenteral nutrition or with evidence of infection were excluded as were patients who had a history of weight loss through dieting or who were anorexic.

Fasting plasma glucagon, serum Cortisol and immunoreactive TNFα concentrations in patients with stage IV breast cancer who had developed weight loss were significantly higher than those in patients with stage IV disease who had not developed weight loss. There were no significant differences in the fasting serum concentrations of insulin, glucose, growth hormone and TSH between the two patient groups.

The association between weight loss in stage IV breast cancer and increased concentrations of plasma glucagon, serum Cortisol and TNFα suggests a possible role for these hormonal factors in the development of cancer cachexia.
Multiple Releasable Fluorescein Labels for Immunoassay: The Principle Illustrated by an Immunoassay for Antibodies to the Human Immunodeficiency Virus
Authors: Bertram V M , Bailey M P , Rocks B F
Published: February 2014

Attempts to increase the sensitivity of fluorescein-based fluorescence immunoassays by using multiple labelling have generally been unsuccessful because of concentration quenching. We have labelled antibodies to human immunoglobulin G with multiple fluorescein fluorophores attached by means of a disulphide linkage: this linkage can be rapidly and easily broken by treatment with dithiothreitol, allowing fluorescein to be released from the antibody and measured in free solution. Application of this technique to a fluorescence labelled immunosorbent assay for antibodies to the human immunodeficiency virus gave an approximately 20-fold increase in signal compared with an equivalent assay using fluorescein isothiocyanate.
Diagnosis of the Abuse of Magnesium and Stimulant Laxatives
Authors: Duncan A , Cameron A , Stewart M J , Russell R I
Published: February 2014

A reliable diagnosis of laxative abuse can only be reached by chemical analysis. We report a modified thin layer chromatography approach for the detection and confirmation of over-the-counter colonic stimulant laxatives. Potential interference by dietary and drug components chemically similar to anthraquinones was investigated and the method was found to be specific in this respect. The diagnosis of magnesium laxative abuse is more difficult since magnesium is a component of body fluids. By inducing diarrhoea with magnesium salts in volunteers we have established that the diagnosis can be made by measuring magnesium concentrations in stool water, with 30 mmol/L being an appropriate cut-off concentration.
Estimation of Fetal Lung Maturity by Assessment of Lamellar Body Particle Concentration
Authors: van Kreel B K
Published: February 2014

The concentration of lamellar bodies expressed as the optical density at 700 nm in amniotic fluid samples was calculated after centrifugation of the samples to obtain the lamellar bodies in a relatively pure form. The lamellar body concentrations obtained were compared with lecithin/sphingomyclin (L/S) ratios from the same samples. The advantages of the method compared with the L/S ratio are discussed as is the dependence on total volume that the method shares with all other procedures which depend on the measurement of a single concentration.
Clinical Evaluation of a Rapid Parathyroid Hormone Assay
Authors: Ryan M F , Jones S R , Barnes A D
Published: February 2014

Modifications to the incubation conditions of radioimmunoradiometric assay for whole molecule parathyroid hormone (PTH) permit accurate quantification of the hormone in the peripheral circulation within 1 h of sampling. We assessed the assay intraoperatively in 75 patients undergoing parathyroidectomy. Serum PTH concentration declined to less than 20% of its pre-operative value within 20 min of the successful completion of surgery provided that renal function was normal. In patients with chronic renal failure the rate of decline in serum PTH concentration after parathyroidectomy was slower in some cases. In four cases of unsuccessful parathyroidectomy, serum PTH concentration remained above 60% of its pre-operative value. Intraoperative monitoring during parathyroidectomy using this rapid PTH assay offers considerable advantages to the surgeon over frozen section.
Urine Calcium and Serum Ionized Calcium, Total Calcium and Parathyroid Hormone Concentrations in the Diagnosis of Primary Hyperparathyroidism and Familial Benign Hypercalcaemia
Authors: Gunn Ian R , Wallace James R
Published: February 2014

A relationship between serum concentrations of ionized calcium and parathyroid hormone (PTH) in persons without parathyroid overactivity was defined by performing an oral calcium load test. As a result, a serum PTH concentration greater than 2·6 pmol/L in a hypercalcaemic patient was regarded as suggestive of hyperparathyroidism. Fasting serum PTH concentrations in 58 patients with surgically and histologically proven primary hyperparathyroidism (PHPT) were all above 2·7 pmol/L (range 3·2–84·5). Thirteen of 20 patients with familial benign hypercalcaemia (FBH) had fasting serum PTH concentrations greater than 2·6 pmol/L (range 1·6–6·1). There was a significant correlation between serum PTH and age in the FBH patients only. Fasting urine calcium excretion (CaE) ranged from 14 to 222 μmol/L of glomerular filtrate in PHPT and 3–34 μmol/L of glomerular filtrate in FBH. The best biochemical discriminant between patients with PHPT and FBH was a plot of fasting serum PTH against CaE. A plot of post-calcium load PTH against post-load CaE showed no further significant advantage in discriminating between the two conditions.
Human Serum and Urine Glycosaminoglycans in Health and in Patients with Chronic Renal Failure
Authors: Bower L , Warren C , Manley G
Published: February 2014

Quantitation of uronic acid precipitable by cetylpyridinium chloride (CPC) and electrophoretic separation of glycosaminoglycans were performed on sera from patients with chronic renal failure and compared to normal controls. Serum CPC-precipitable uronic acid (CpUA) levels in patients with renal failure were significantly higher (mean 13·7 mg/L, range 7·1–23·6 mg/L) than normal controls (mean 9·6 mg/L, range 5·1–13·9 mg/L) due to increased concentrations of low sulphated chondroitin sulphate. A positive correlation between serum CpUA and creatinine was found in renal failure patients.

Urine CpUA excretion was raised in renal failure patients compared to normal controls with an increased excretion of chondroitin sulphate (Ch-S) of reduced electrophoretic mobility. Heparan sulphate (HS), a major glycosaminoglycan in normal urine, was absent from the urine of these patients.

The possible origin of urine glycosaminoglycans and the role of the kidney in glycosaminoglycan metabolism are discussed.
Accessibility and Function of Human Thyroid Epithelial Cells in Monolayer Culture
Authors: de Rave S , van Deursen-Ketelaars M-J , Loosveld O J L , Goldschmidt H M J
Published: February 2014

Measurement of thyroid stimulating immunoglobulins (TSI) has not yet found widespread application in the diagnosis and management of Graves' disease. One of the problems is the poor and variable sensitivity of the different assays. We therefore studied the influence of the accessibility of the basal part of human thyroid epithelial cells in monolayer culture on their cAMP response to thyroid stimulating hormone (TSH) and TSI. Test media containing either ammoniumsulphate-precipitated globulin fractions of sera from normal controls and treated or untreated patients with Graves' disease or TSH were used to stimulate cAMP production by cryopreserved human thyroid epithelial cells in monolayer culture. Incubations with and without the use of porous membrane inserts as culture surface were compared by univariate parametric and non-parametric testing. It appears that more TSH-receptors, probably on the basal part of the thyrocyte, can be exposed to the medium by using a porous membrane as culture surface as demonstrated by the increased analytical sensitivity of the semi-bioassay of TSH and TSI.
The Contribution of Steroids to Digoxin-Like Immunoreactivity in Cord Blood
Authors: Yun Wong Shun , Ho C S , Panesar N S , Swaminathan R
Published: February 2014

Samples of cord serum from 29 healthy neonates were analysed for digoxin-like immunoreactive substance (DLIS), cortisol, 17β-oestradiol, progesterone, dehydroepiandrosterone-sulphate (DHEAS), 17α-hydroxyprogesterone (17OHP), androstenedione, oestriol and ouabain-like activity (OLA; by inhibition of Na+,K+ ATPase activity). The mean serum concentration of DLIS was 0·91 (SD = 0·19) nmol/L and the mean OLA was 26·1 (SD = 11·5) nmol/L. There was no correlation between DLIS and OLA. DLIS correlated significantly with oestriol ( r = 0·521), progesterone ( r = 0·534) and 17OHP ( r = 0·43). Stepwise multiple regression analysis showed that 17β-oestradiol, progesterone and androstenedione contributed to DLIS and the intercept was 0·64 (SD = 0·127). The concentrations of steroids (17β-oestradiol, progesterone, androstenedione) required to displace digoxin by 50% in the digoxin immunoassay and inhibit Na+,K+ ATPase in the OLA assay were 103–104-fold higher than those found in cord serum. We conclude that the contribution of these steroids to DLIS is small and that DLIS and OLA measure different compounds.
Abnormal Endogenous Carbon Monoxide Production in Children with Ineffective Erythropoiesis
Authors: Sannolo N , Farina V , Fiorillo A
Published: February 2014

The aim of this study was to evaluate the extent of endogenous carbon monoxide production in subjects with ineffective erythropoiesis. Carboxyhaemoglobin concentrations were measured in eight transfused and eight nontransfused thalassemic patients. Measurements were made on venous blood collected under controlled conditions and were corrected by simultaneous measurement of HbF levels. Nontransfused thalassaemic patients with abnormal erythropoiesis were found to have elevated levels of carboxyhaemoglobin, significantly higher than those found in transfused subjects, as well as decreased cardiac performance. It is important to consider carboxyhaemoglobin levels in planning transfusion programmes.
A Simple Method for the Measurement of Different Forms of α1 Proteinase Inhibitor in the Faeces of Patients with Crohn's Disease
Authors: Yamani J El , Soudan B , Mizon C , Colombel J F , Balduyck M , Cortot A , Mizon J
Published: February 2014

Alpha-1 proteinase inhibitor (α1PI), formerly named α1-antitrypsin, is excreted in the faeces of patients with Crohn's disease as isoforms clearly separated by SDS-PAGE and immunoblot analysis. Relapses in Crohn's disease are generally associated with the appearance in faeces of Mrs 51 000 and 45 000 glycosylated forms of α1PI, as compared with normal subjects and most of the patients in quiescent phases of their disease who excrete an M r 38 000 unglycosylated form of α1PI. We used their differential Concanavalin-A reactivity to design a specific test. The proposed assay is potentially helpful for the follow-up of patients under therapy and for early recognition of attacks of Crohn's disease.
Method Comparison—A Different Approach
Authors: Pollock M A , Jefferson S G , Kane J W , Lomax K , MacKinnon G , Winnard C B
Published: February 2014

The commonly accepted method of analysing data from method comparison studies is regression analysis, a method which has limitations. This study illustrates the use of a graphical presentation of data, the difference plot, which can be used as an alternative to least squares regression analysis. The data from comparison studies performed on five methods were analysed both by Deming's regression analysis, with calculation of the correlation coefficient, and by the difference plot. The results show that in most cases much more relevant information was obtained from the difference plot.
Measurement of Sialic Acid in Serum and Urine: Clinical Applications and Limitations
Authors: Waters Paula J , Lewry Elizabeth , Pennock Charles A
Published: February 2014

Many recent studies have examined the sialic acid content of serum or urine in various pathological states. We have briefly reviewed the substances which contribute to the observed total sialic acid concentration, and given an overview of assay methods used.

Three major areas of clinical interest in sialic acid metabolism are discussed. Serum total sialic acid, ‘lipid-bound’ and ‘protein bound’ sialic acid have all been proposed as tumour markers; but the usefulness of any of these tests is severely limited by changes due to accompanying inflammatory processes. Serum total sialic acid is not a valuable simple marker of an acute phase response. Urinary free and bound sialic acid measurements should be included in screening protocols for inherited disorders of lysosomal metabolism. Current developments in research and potential applications within the clinical biochemistry laboratory are briefly discussed.
Radioimmunoassays of Arginine Vasopressin and Atrial Natriuretic Peptide: Application of a Common Protocol for Plasma Extraction Using Sep-Pak C18 Cartridges
Authors: Penney M D , Hampton D , Oleesky D A , Livingstone C , Mulkerrin E
Published: February 2014

A rapid vacuum-driven procedure, using pre-treated Sep-Pak C18 cartridges, has been developed for the simultaneous extraction of arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) from plasma. Non-specific interference was removed by fractional elution with an aqueous methanol/trifluoroacetic acid (TFA) mixture. AVP and ANP were coeluted under positive pressure with a methanol/TFA mixture and the eluates air-dried before measurement using separate radioimmunoassays.

Assay ranges for AVP and ANP were 0·12–29·5 pmol/L and 0·65–162 pmol/L, respectively, with mean recoveries (standard deviation in parentheses) for AVP of 96·4% (5·5%) at a level of 11·8 pmol/L and for ANP of 94·8% (5·9%) at a level of 32·4 pmol/L.

The extraction and assay procedures were validated by observing the changes in plasma AVP and ANP concentrations in normal subjects at different stages of hydration and in elderly patients during treatment for congestive cardiac failure.
Improved Flow Cytometric Method for HLA-B27 Typing
Authors: Janssen W C M , Rouwen J A C N , Hoffmann J J M L
Published: February 2014

HLA-B27 is a cell marker of clinical interest because of its high association with certain diseases. The HLA-B27 antigen was detected on lymphocytes using a monoclonal antibody in an indirect immuno-fluorescence assay using a fluorescence flow cytometer. The considerable crossreaction of the monoclonal antibody with the HLA-B7 antigen was effectively suppressed by masking it by means of human anti-HLA-B7 antiserum. The flow cytometric method was evaluated by comparing the results with those obtained by the standard lymphocytotoxicity test and showed complete agreement in 107 selected patient samples.
Serum Calcium, Parathyroid Hormone, and Vitamin D Status in Children and Young Adults with Sickle Cell Disease
Authors: Mohammed S , Addae S , Suleiman S , Adzaku F , Annobil S , Kaddoumi O , Richards J
Published: February 2014

The concentrations of serum calcium, parathyroid hormone (PTH), 25 Hydroxyvitamin D (25OHD), and 1,25 Dihydroxyvitamin D (1,25(OH)2D) were determined in 99 Saudi patients with sickle cell disease and in 104 matching healthy controls. Serum calcium and 25OHD were significantly lower in the patients, with 14% and 12% of them had serum calcium and 25OHD concentrations, respectively, below the normal range. PTH was significantly higher in the patients, with 31% having values above the normal range. There was no significant difference between patients and controls in regard to 1,25(OH)2D. There was a significant inverse correlation of 25OHD with PTH and a direct correlation of PTH with 1,25(OH)2D. Dietary intake of calcium and vitamin D was adequate in both patients and controls. The results indicate that sickle cell patients have hypocalcaemic tendency associated with supranormal PTH, and imply impaired intestinal absorption of calcium and vitamin D leading to a disturbed calcium metabolism which might contribute to the skeletal changes seen in sickle cell disease.
A Rapid Method for Measuring Serum Amyloid a Protein by Latex Agglutination Nephelometric Immunoassay
Authors: Yamada Toshiyuki , Nomata Yasuhiro , Sugita Osamu , Okada Masahiko
Published: February 2014

Serum amyloid A protein (SAA) is a sensitive acute phase react ant. We developed a method for the rapid measurement of human SAA in serum by kinetic nephelometry of anti-SAA antibody-coated latex agglutination. Measurement takes less than 6 min using an automated analyser. Standardization of the assay employs SAA-enriched high density lipoprotein as the primary standard. The values determined by our new method and by conventional enzymeimmunoassay showed good agreement ( r = 0·988). The normal range was 0·17–10·0 mg/L [mean (SD)]. This rapid method should prove useful in clinical laboratories.
Estimation of Sulphoconjugated Catecholamine Concentrations in Plasma by High-Performance Liquid Chromatography
Authors: Yoshimura Manabu , Komori Toshiaki , Nakanishi Tadashi , Takahashi Hakuo
Published: February 2014

Free and sulphoconjugated catecholamine (CA) concentrations were measured in plasma using a fully automated and sensitive analyser equipped with a three-column system of high-performance liquid chromatography (HPLC). Although the free dopamine (DA) concentration has been below the detection limit of HPLC analysers thus far available, this new CA analyser can measure as little as 0·03 nmol/L. For the estimation of sulphoconjugated CA, we performed enzymatic deconjugation with arylsulphatase prior to HPLC analysis. The difference between free and total concentrations represents that of sulphoconjugated CA. The intraassay coefficient variation was less than 2·2% for free noradrenaline (NA) and adrenaline (A), 12·62% for free DA, and less than 4·3% for total A, and DA. These assays of free and sulphoconjugated CA are simple and can be performed routinely by a suitably equipped laboratory.
A Robust Procedure for the Automated Measurement of Total Serum Bilirubin Using Potassium Ferricyanide
Authors: O'Leary Niall , Pembroke A , Duggan P F
Published: February 2014

Bilirubin is oxidized to biliverdin by 1·0 mmol/L potassium ferricyanide in the presence of caffeine. The absorbance decline at 480 nm with blanking at 660 nm is proportional to bilirubin concentration. The assay is linear up to 1000μmol/L and is suitable for the measurement of bilirubin in adult and neonatal patients. The assay is accurate and precise and is not significantly affected by haemolysis up to 5·0 g/L haemoglobin. Reagents and calibration are stable for at least 3 months.
Bone-Derived Serum Enzymes and Bone Density in Perimenopausal Caucasian Women
Authors: Johnston J D , Koneru S , Kuwana T , Rosalki S B
Published: February 2014

Serum levels of bone-origin alkaline phosphatase and of tartrate-resistant acid phosphatase were measured in Caucasian women aged 41–69 years who had volunteered for bone densitometry. Bone alkaline phosphatase and tartrate-resistant acid phosphatase were inversely correlated with vertebral bone density and with femoral neck bone density. Bone alkaline phosphatase and acid phosphatase were also significantly correlated, consistent with the concept of ‘coupling’ between osteoblast and osteoclast activity.
Biological Variation in Glycated Proteins
Authors: Davie Sarah J , Whiting Kerry L , Gould Barry J
Published: February 2014

The high degree of individuality in the fructosamine assay has been ascribed to non-specific interferences in the assay. To investigate this, we measured the biological variability of 10 non-diabetic subjects using the fructosamine assay, the new fructosamine plus assay, glycated albumin and glycated total plasma proteins by affinity chromatography.

The total variation of the two fructosamine assays was half that of the affinity chromatography assays. This was mainly due to the greater analytical imprecision of the affinity chromatography assays. The resulting high index of heterogeneity for both affinity methods makes it difficult to assess the significance of changes in serial results.

The within-subject variation made a small contribution to the total variation for all the assays, and was particularly low for the fructosamine assays. This suggests that any non-specific component makes a constant contribution to the measured fructosamine activity in non-diabetic subjects.

The fructosamine assays therefore have significant advantages over the affinity chromatography methods as indices of medium-term glycaemic control.
Serum Total Sialic Acid and Lipid-Associated Sialic Acid in Normal Individuals and Patients with Myocardial Infarction, and Their Relationship to Acute Phase Proteins
Authors: Haq M , Haq S , Tutt P , Crook M
Published: February 2014

Serum total sialic acid (TSA) has gained medical interest, particularly as a cardiovascular risk factor and it has been hypothesized that serum levels relate to serum acute phase proteins, some of which are sialylated. We assayed serum TSA and also lipid associated sialic acid (LASA) in SO normal individuals (24 male) and IS subjects (12 male) who had experienced a myocardial infarct. The mean serum TSA in the normal individuals was 2·05 SD 0·38 mmol/L (range 1·16–2·74) and the mean serum LASA was 0.70 SD 0·19 mmol/L (range 0·23–1·03). We also measured five serum acute phase proteins and found a good correlation between these and serum TSA: C-reactive protein, r = 0.52, P<0.001, α-1-antichymotrypsin, r=0·79, P<0·0001, α-2-macroglobulin, r=0·38, P<0·01 and α-1-acid glycoprotein, r=0·32, P<0·05. A significant correlation between plasma TSA and plasma C-reactive protein ( r = 0·47, P<0·04) and also Fibrinogen ( r=0·53, P<0·04) was noted on day one following the myocardial infarction, whereas a significant correlation between plasma TSA and plasma α-1-antichymotrypsin ( r=0·51, P<0·03) and also plasma α-1-acid glycoprotein ( r=0·64, P<0·05) was found on day two following the infarction. Thus it would seem that serum TSA is at least in part related to some of the acute phase proteins in both healthy individuals and those having had a myocardial infarction.
A Pilot Scheme for Improving the Accuracy of Serum Cholesterol Measurement in Scotland and Northern Ireland
Authors: Packard C J , Bell M A , Eaton R H , Dagen M M , Cassidy M , Shepherd J
Published: February 2014

The measurement of plasma cholesterol is subject to particularly stringent requirements of bias and imprecision because clinically important action limits lie within the bulk of the population distribution. A pilot scheme was conducted with the aim of improving the accuracy of the assay of cholesterol in 26 laboratories in Scotland and Northern Ireland. This involved the distribution of three sets of authentic human sera with varying cholesterol concentrations assigned by the reference Abell-Kendall method which was established and validated in a central laboratory.

The precision (coefficient of variation) of cholesterol testing was 1·71% across all laboratories at the first distribution and this did not alter subsequently. Mean bias was initially 4·07% (median 4·14%) relative to the Abell-Kendall assigned values and this figure had fallen to 1·12% (median 0–92%) by the third distribution.

We conclude that through a standardization scheme it is possible in a relatively short time to improve bias significantly and meet the criterion of < 2–3% bias required for optimum cholesterol measurement.
The Effect of Microalbuminuria on Glycaemic Control, Serum Lipids and Haemostasis Parameters in Non-Insulin-Dependent Diabetes Mellitus
Authors: Donders S H J , Lustermans F A T , van Wersch J W J
Published: February 2014

Microalbuminuria is an important risk factor for cardiovascular disease in non-insulin-dependent diabetes mellitus (NIDDM) patients although the pathogenic mechanism between microalbuminuria and cardiovascular disease has not yet been established. Microalbuminuria in insulin-dependent diabetes mellitus (IDDM) patients has been related to abnormalities in haemostasis, poor glycaemic control, disadvantageous alterations in the lipid spectrum and elevated concentrations of lipoprotein(a), another independent risk factor for cardiovascular disease.

In this study the interrelations between microalbuminuria and metabolic control, lipoprotein(a), other blood lipids and several haemostasis parameters were studied in 96 NIDDM patients (50 women, 46 men). Forty-three patients showed microalbuminuria. No significant differences were found in blood lipids (Lp(a), serum cholesterol, low-density lipoprotein and high-density lipoprotein cholesterol and triglycerides), glycaemic control (HbA1c) and several haemostasis parameters (factor VII, VIII, fibrin monomer, thrombin-antithrombin III, D-dimer, tissue plasminogen activator antigen and plasminogen activator inhibitor-1) between the micro- and normoalbuminuric subgroups. In the microalbuminuric subgroup increased concentrations for plasminogen and α2-antiplasmin were measured.

In general, the presence of microalbuminuria was not associated with significant alterations in glycaemic control, blood lipids or haemostasis parameters in this group of 96 NIDDM patients. Further investigation is required to explain the excess cardiovascular mortality in patients with an elevated urinary albumin excretion rate.
A Blood Spot Assay for Apo A1 and B Lipoproteins and the Apo B/A1 Ratio
Authors: Hirst A D , Beswick K
Published: February 2014

A study of conditions for the elution of apo A1 and B lipopoproteins from dried blood spots has led to the development of an apo B/A1 ratio assay with results for dried blood spots which are comparable with serum assays. This assay has been developed to be suitable for large scale population screening. The concept of measuring ratios for co-eluting blood constituents improves the accuracy and precision of blood spot assays and opens up the possibility that patients could take their own blood sample and send it to the laboratory by post.
Serum Ultrafiltrable Copper, Total Copper and Caeruloplasmin Concentrations in Gynaecological Carcinomas
Authors: Chan Anita , Wong Felix , Arumanayagam Mano
Published: February 2014

Serum copper and caeruloplasmin concentrations are elevated in various carcinomas, but it is not known whether the rise in serum copper is due to elevation of caeruloplasmin alone or whether it is also due to the elevation of ‘free’ copper. We therefore determined ultrafiltrable copper to answer this question. Serum ultrafiltrate was prepared using the Amicon micropartition system and ultrafiltrable (free) copper was determined by flameless atomic absorption spectrophotometry. Serum total copper was determined by flame atomic absorption spectrometry and caeruloplasmin by rate nephelometry. There was no significant difference in the ultrafiltrable copper concentration between patients with gynaecological tumours and control subjects. However, total copper and caeruloplasmin concentrations were significantly elevated in cancer patients compared with control subjects. In contrast to total copper and caeruloplasmin concentrations, ultrafiltrable copper concentrations showed no significant increase with increase in the stage of the cancer.
The Association between Hepatitis C Virus Infection and in Vitro Activation of the Complement System
Authors: Ueda Kazuhito , Nakajima Hideto , Nakagawa Toshimasa , Shimizu Akira
Published: February 2014

The phenomenon of in vitro activation of the classical complement pathway at low temperatures (4–21°C) is known as cold activation, and has been suggested to be associated with non-A, non-B hepatitis. We re-examined the association by using newly developed markers of hepatitis C virus (HCV) infection. Twenty-one cases randomly selected from those fulfilling the screening criteria of complement cold activation all showed evidence of HCV infection. More than half of 55 HCV antibody-positive cases selected randomly from our laboratory samples showed a tendency towards cold activation, whereas none of the HCV antibody-negative sera showed cold activation. All the HCV antibody-positive cases were negative in cold activation when CH50 was assayed with plasma. These results, taken together, indicate that cold activation of the complement system is strongly associated with HCV infection.
Avidin-Biotin Based Electrochemical Immunoassay for Thyrotropin
Authors: Athey Dale , Ball Mark , McNeil Calum J
Published: February 2014

A two site electrochemical enzyme immunoassay for thyrotropin (TSH) has been developed. This assay is based on the use of an immobilized capture antibody and a biotinylated second antibody. Detection is achieved via avidin labelled with alkaline phosphatase. The substrate 1-naphthyl phosphate was used and the product 1-naphthol was detected at disposable screen-printed carbon 8-electrode combs using specially designed instrumentation.
Comparison of Paired Short Synacthen and Insulin Tolerance Tests Soon after Pituitary Surgery
Authors: Jackson R S , Carter G D , Wise P H , Alaghband-Zadeh J
Published: February 2014

The cortisol responses to hypoglycaemia (insulin tolerance test, ITT) and tetracosactrin (short Synacthen test, SST) were compared after hypophysectomy to evaluate the SST for the assessment of hypothalamo-pituitary-adrenocortical (HPA) axis function in the immediate post-operative period. In 12 patients who were tested a mean of 21 months postoperatively (range 1–96) peak plasma cortisol in the SST correlated with that in the ITT ( r = 0·90). Correlation was also seen in 12 patients tested a mean of 9 days (range 4–18) after hypophysectomy ( r = 0·73). Basal-peak cortisol increments did not correlate. The peak plasma cortisol response in each test was classified by comparison with a reference value of 550 nmol/L. On this basis there was a notable discrepancy between the ITT and SST results in only one patient who was tested 4 days after hypophysectomy.

The close correlation between ITT and SST responses after pituitary surgery extends into the immediate post operative period and indicates that the latter test can be used to screen HPA axis function at this time.
Lack of Evidence for Aromatase Expression in Human Ovarian Epithelial Carcinoma
Authors: Imai Atsushi , Ohno Tsukasa , Takahashi Kyoko , Furui Tatsuro , Tamaya Teruhiko
Published: February 2014

It is controversial whether ovarian epithelial carcinoma possesses steroidogenic enzymes. We investigated aromatase expression in ovarian epithelial carcinoma, and compared it with the normal ovary and placenta. Samples were obtained from an ovarian carcinoma cell line SK-OV-3, ovarian tumour tissues from four patients with epithelial carcinoma and one patient with dysgerminoma. Aromatase enzymatic activity was measured in microsome fractions by quantitating 3H2O released from [1-3H]androstenedione and [3H]oestrone converted from [1,2,6,7-3H]androstenedione. Aromatase messenger ribonucleic acid (mRNA) was determined by reverse transcription-polymerase chain reaction (RT-PCR) using oligonucleotide primers synthesized according to the published human aromatase gene sequence.

No aromatase activity was detected in either of two mucinous cystadenocarcinoma specimens or in SK-OV-3 cells, while aromatization proceeded with apparent Michaelis-Menten kinetics in the normal ovaries and placentas. The apparent Km value was 200 nmol/L for the ovary. Aromatase mRNA was detected in dysgerminoma, and the normal ovary and placenta, but not in any of three mucinous cystadenocarcinoma specimens, one serous cystadenocarcinoma specimen and SK-OV-3 cells. These results for both enzyme activity and gene expression suggest that the human ovarian epithelial carcinoma lacks aromatase. The demonstration of absence of aromatase gene expression raises the possibility that aromatase activity in ovaries bearing epithelial carcinoma may be associated with hyperplastic stromal rather than tumour cells.
Interference by Parvolex with Chloride Estimation by the Ag/AgCl Method
Authors: Bishell G P , Lewis H , Rooke R A , Davies H R
Published: February 2014

We demonstrate significant interference by Parvolex (acetylcysteine) with the Ag/AgCl method for chloride estimation. A study of four patients who had taken a paracetamol overdose and been treated with Parvolex implied this interference, and an in vitro study confirmed it. The interference was shown to decline upon storage of the serum at a similar rate in both the patient and in vitro studies. Suggested mechanisms for these phenomena are given.
Elimination of Bilirubin Interference in Creatinine Assays by Routine Techniques: Comparisons with a High Performance Liquid Chromatography Method
Authors: Boot Sandra , LaRoche Nicholas , Legg Edward F
Published: February 2014

The aim of this study was to find a method for creatinine analysis unaffected by jaundice by comparing four different methods with high performance liquid chromatography (HPLC) as a reference method. The methods investigated were Kodak DTSC single slide, Boehringer alkaline picrate with and without blank correction and a Boehringer enzymatic method, the last three using the Hitachi 737 analyser.

HPLC results were compared with the results of the methods studied. In addition, graphs plotting the difference from the HPLC result against the bilirubin concentration were made; the ideal method would yield a slope and intercept of zero.

While all methods showed a positive bias compared with HPLC, the Kodak slide and the Boehringer alkaline picrate with blank correction methods eliminated bilirubin interference and we have changed to the latter method as a consequence of this work.
Intra-Individual Variation in Fasting Urinary Calcium- and Hydroxyproline-Creatinine Ratios Measured in Metabolic Bone Clinic Patients as Both Outpatients and Inpatients
Authors: Vasikaran S D , McCloskey E V , Kahn S , Kanis J A
Published: February 2014

The total intra-individual variation of fasting urinary calcium- and hydroxyproline-creatinine ratios were determined both as outpatients and as inpatients in 46 patients with metabolic bone disorders, including 20 women with osteoporosis. The intra-individual variation of both measurements was reduced considerably by collecting samples in the ward rather than in the outpatient setting, although this was not the case for a sub-group of osteoporotic women. The large intra-individual variation observed for calcium and hydroxyproline (30–40% in osteoporotic women) can give rise to misclassification in screening for fast bone losers. The very large critical difference required (109% and 94%, respectively, for calcium and hydroxyproline) for two results to reflect a significant change, is a major limitation in the use of these analytes for monitoring bone resorption in menopausal and osteoporotic women.
Salivary Theophylline Concentrations in Neonates
Authors: Thompson Susan J
Published: February 2014

Salivary theophylline concentrations in neonates were measured by a homogeneous enzyme immunoassay and compared with serum concentrations. Free serum theophylline concentrations were also compared with salivary concentrations and the values obtained were almost identical. Results using the immunoassay agreed well with those obtained using a high-performance liquid chromatographic procedure (HPLC).
Comparison of Serum Osteocalcin with Total and Bone Specific Alkaline Phosphatase and Urinary Hydroxyproline: Creatinine Ratio in Patients with Paget's Disease of Bone
Authors: Kaddam I M S , Iqbal S J , Holland S , Wong M , Manning D
Published: February 2014

Osteocalcin or bone Gla protein (BGP) is secreted by osteoblasts, and its serum concentration is elevated in a number of conditions with high bone turnover. A comparison of serum osteocalcin with total (TALP) and bone specific alkaline phosphatase (BALP) and urinary hydroxyproline/creatinine (OHP/Cr ratio) was performed in 13 patients with active Paget's disease of bone. BGP did not correlate significantly with either BALP or TALP, but did show a significant correlation with OHP/Cr ratio ( r = 0·76; P<0·01). BGP does not appear to be as sensitive a marker as BALP or TALP in Paget's disease.
Distribution of Serum Lipoprotein (a) Concentrations in a Healthy Turkish Population
Authors: Örem Asim , Değer Orhan , Önder Ekin , Karahan S Caner , Efe Hasan , Uzunosmanoğlu Derya
Published: February 2014

Serum lipoprotein (a)[Lp (a)] concentrations are highly skewed in different populations. We measured serum Lp (a) by quantitative enzyme-linked immunosorbent assay (ELISA) in 248 healthy Turkish subjects (127 male, 121 female). The mean Lp (a) value was 0·21 g/L and values did not differ between the sexes. The Lp (a) frequency distribution showed less skewness than those of Asian and Western populations but it clearly deviated from a Gaussian distribution. Plasma Lp (a) concentration did not correlate significantly with age, total cholesterol, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, apolipoprotein A-l and B or triglyceride concentration.
Use of Dynamic Tests of Muscle Function and Histomorphometry of Quadriceps Muscle Biopsies in the Investigation of Patients with Chronic Alcohol Misuse and Chronic Fatigue Syndrome
Authors: Wassif W S , Sherman D , Salisbury J R , Peters T J
Published: February 2014

Ischaemic lactate/ammonia tests, serum carnosinase and creatine kinase assays and percutaneous needle muscle biopsies were performed on 10 patients with chronic fatigue sydrome (CFS), and 10 with chronic alcohol misuse complaining of muscular symptoms. Basal serum lactate levels were significantly elevated in the alcohol misusers compared to the CFS patients, but all were within the reference range. Lactate profiles after ischaemic forearm exercise did not differ significantly for the two patient groups. In one patient previously diagnosed as having CFS, myoadenylate deaminase deficiency was identified on the basis of a flat ammonia response to ischaemia and absent muscle adenosine monophosphate deaminase activity. In addition, two further patients in the CFS group were subsequently shown to have other disorders: one had polymyositis and one had myopathy with mild type II fibre atrophy of unknown cause. Histomorphometric examination of muscle needle biopsy in the alcohol misusers showed features of chronic alcohol-induced skeletal myopathy in six patients and polymyositis in one patient. Type II fibre atrophy factors were significantly elevated in the alcohol group but were within the reference range in CFS patients. Dynamic tests of muscle function and muscle histology are valuable tools in excluding alternative pathology in CFS, whereas muscle histomorphometry is of the greatest value in the diagnosis of chronic alcoholic myopathy.