bluuebunny/crossref_metadata_2025 huggingface dataset:
Age- and Gender-Related Changes in Ligament Components
Authors: Osakabe T , Hayashi M , Hasegawa K , Okuaki T , Ritty T M , Mecham R P , Wachi H , Seyama Y
Published: February 2014

The age- and gender-related changes in extracellular matrix components (elastin, elastin cross-links, fibrillin, collagen and glycoprotein) and mineral components (calcium, Ca; phosphorus, P) in human lumbar yellow ligaments were investigated using samples obtained from surgical specimens. The mineral (Ca and P) contents increased with ageing ( r=0·703 and r=0·772, respectively), whereas the contents of matrix components tended to decrease with ageing (elastin r= −0·261, elastin cross-links r= −0·213, fibrillin r= −0·494; collagen r= −0·322 and glycoprotein r= −0·143). Comparison of the male and female groups revealed that the ligament elastin content and elastin cross-links decreased in the male group, whereas the ligament collagen content decreased in the female group significantly in an age-dependent manner ( r= −0·788, r= −0·753 and r= −0·721, respectively). These findings demonstrate age- and gender-related changes in mineral and matrix components (especially elastin and collagen) in the lumbar yellow ligaments in the Japanese population. It is suggested that elastin and collagen metabolism in ligaments changes both with age and according to gender.
Positive Screening Tests for Barbiturates in Urine Samples in the York Area over a 1-Year Period
Authors: Holbrook Ian , Sinclair Margaret , Turley Paul , Tetlow Tony
Published: February 2014

Following the screening of urine samples for a panel of drugs over a period of 1 year, a peak was observed during December 1999 and January 2000 in the numbers of samples testing positive for both morphine and barbiturates. This increase may be due to the adulteration of street heroin with barbiturate during this period.
Hyperamylasaemia and Multiple Myeloma
Authors: Ross Colleen M , Devgun Manjit S , Gunn Ian R
Published: February 2014

This case report describes a 42-year-old Caucasian woman who presented with persistent hyperamylasaemia and no evidence of pancreatic pathology Further investigations resulted in a diagnosis of light-chain multiple myeloma. Amylase production by epithelial tumours has been well documented but the association with multiple myeloma has only been described in a small number of cases. The link does not appear to be immunoglobulin class-specific but the association with Bence Jones myeloma is unusual. The common features in this group of patients have been extensive extramedullary spread with a high tumour mass and a poor prognosis. This case was similar in that the patient showed very rapid disease activity developing extensive metastatic lesions and treatment ultimately proved unsuccessful. The amylase concentrations have been shown to decrease in response to treatment and increase at times of relapse and it has been proposed that it may be useful as a tumour marker in these patients. This case study adds to the pool of patients with this unusual association.
Screening for Inherited Metabolic Disorders: A New Look at Metabolic Screening Tests
Authors: Seakins J. W. T. , Haktan Makbule , Andrew B. C. , Ersser R. S.
Published: February 2014

Simple methods for the detection of inborn errors of metabolism which result in the accumulation of metabolites in blood or urine are described and the significance of abnormal findings reviewed.
Prenatal Screening for Inborn Errors of Metabolism
Authors: Ellis R. B.
Published: February 2014

The problems likely to be encountered and the limitations of present methods of pre-natal diagnosis of inborn errors of metabolism by assay of the deficient enzyme activity is emphasised. Particular attention is given to the problems of testing the correct enzyme deficiency, choosing the most appropriate foetal sample, and of minimising the effects of maternal contamination.

For those disorders which are recessively inherited, the feasibility of mass screening for the detection of marriages between carriers is considered as a means whereby all foetuses at risk for a given condition may be recognised.
Selection of a Dedicated Computer System for Clinical Laboratories
Authors: Tonks D. B.
Published: February 2014

The DEC Clini Lab — 12 System of the Montreal General Hospital is described. The reasons for selecting it are given and brief comparisons are made with two other rather similar commercial systems. Some insight is given into installation problems.
Comparative Study of Thyroxine Assays Employing Kit Radio-Ligand Reagents
Authors: Watson D. , Lees S.
Published: February 2014

A comparative study of some ‘kit’ radiometric procedures for the determination of thyroxine in serum is reported. Four manufacturers' competitive-binding reagents and methods—three incorporating prior extraction and one employing column elution—are examined. Considerable discrepancies exist between the manufacturers' ‘standards’ which, in the main, account for the differences in results obtained by the different methods. Other deficiencies include susceptibility to metal ion interference, variation (up to 8%) in thyroxine extraction and non-specific, i.e. ‘mimic T-4’, measurement.

Radio-ligand reagent ‘kits’ need to be critically assessed before being used routinely. Separation of hypo-and hyperthyroid from euthyroid patients is achieved as well with some competitive protein-binding T-4 methods as with serum PBI.
Contamination from Syringes and Blood Container Pots in Trace Element Analysis
Authors: Taylor A. , Marks V.
Published: February 2014

Syringes, blood container pots and test tubes have been investigated to determine whether they act as sources of contaminants during trace element analyses. Urine containers were investigated to decide which materials do not absorb mercury from dilute solutions.

No copper and little magnesium contamination was found. Zinc contamination was unpredictable. Very large amounts of zinc leached from the rubber end cap of the piston of disposable, plastic sterile syringes.

The B.S.I. Standards for disposable syringes were shown to be unacceptable for heavy metals.
Determination of Plasma Calcium Fractions
Authors: Varghese Z.
Published: February 2014

A simple, precise, and sensitive method is described for the determination of ionised calcium in plasma at normal body temperature and pH, using an ultrafiltrate of the plasma. This technique is based on a two-wave-length (480 nm, 550 nm) spectrophotometric method, using pH independent dye ammonium tetramethylmurexide (ATM). By this method, the normal (mean + 2 S.D.) plasma ionised calcium in 19 normal subjects is 1.04 + 0.14 mmol/l which is similar to some of those reported for ion-selective electrode measurements.
Radioimmunoassay Kits for Human Placental Lactogen
Authors: Wheeler M. J. , Watson D.
Published: February 2014

Six commercially-available radioimmunoassay reagent kits for the measurement of human placental lactogen (chorionic sommatomammotrophin) have been examined. Each procedure has been studied for precision, reliability, economy, simplicity and accuracy. Satisfactory results with late pregnancy sera, obtainable within 4 h, can be achieved using the reagents supplied by Wellcome Reagents Ltd. and The Radiochemical Centre.
Steroid Excretion by an Infant with an Unusual Salt-Losing Syndrome: A Gas Chromatographic–Mass Spectrometric Study
Authors: Shackleton C. H. L. , Snodgrass G. H. A. I.
Published: February 2014

The excretion of steroids by an infant with pseudohypoaldosteronism is reported. The patient presented with symptoms of hyperkalaemia and hyponatraemia, and was maintained for a period on a high salt intake and mineralocorticoids. However, he collapsed on the 48th day of life and could not be resuscitated.

The urinary steroids were identified by combined gas chromatography–mass spectrometry and quantitation was achieved by gas chromatography. The following steroids were identified: tetrahydroaldosterone, tetrahydrocortisone, α- and β-cortolone, 1 β-hydroxytetrahydrocortisone, 1 β-hydroxycortolone, tetrahydrocorticosterone (THB), tetrahydro-11-dehydrocorticosterone (THA), 3α, 20α, 21-trihydroxy-5β-pregnan-ll-one, 5-pregnene-3β, 16α, 20α, 21-tetrol, and 5-androstene-3β, 16αa, 17β-tiiol.

The patient evidently secreted an excess of aldosterone so the disorder was probably due to a form of renal-tubule unresponsiveness to this hormone. Some of the urinary steroids normally excreted in large amounts during infancy (16α-hydroxy DHA, 16-oxo-androstenediol, and 16α-hydroxypregnenolone) were not detected in the urine samples, and it is suggested that the precursor of these steroids (pregnenolone) was being fully utilised in the synthesis of aldosterone and cortisol.
Long-term Variations in Serum Calcium Concentration in Normal Subjects
Authors: Lester Eva , Wills M. R.
Published: February 2014

In 20 healthy normal Caucasian subjects the serum calcium concentration was measured at three-monthly intervals over two and a half years. There was no evidence of any seasonal variation in serum calcium concentration as a result of variation in endogenous cholecalciferol synthesis.
Simplified Gas Chromatographic Assay for Paracetamol
Authors: Stewart M. J. , Willis R. G.
Published: February 2014

A rapid gas liquid chromatography method has been developed which is suitable for emergency estimations of paracetamol in overdose. The method is compared with a standard ultraviolet method.
A Comparative Study of Manual Methods for Serum Triglyceride Estimation
Authors: Goldfinhc M. E. , Prudhoe K.
Published: February 2014

A comparison is made of the accuracy, precision, and convenience of two manual serum triglyceride methodologies based on solid phase adsorption and liquid phase partition procedures. Both methods are accurate but the precision and convenience of the latter is far superior.

The use of home made reagents reduces the cost of both substantially below that of any commercial alternative, including the popular enzymatic methods.
An Evaluation of the Greiner Selective Analyzer and its Role in the Clinical Laboratory
Authors: Skinner Andrew G. , Wilding Peter
Published: February 2014

The Greiner Selective Analyzer (GSA II) was evaluated over a period of six months. The evaluation assessed the reliability, accuracy, and precision of the analyser for six determinations. The methods evaluated were for glucose, urea, creatinine, total protein, total bilirubin, and alkaline phosphatase. Comparison of results was also made with those obtained for the same specimens using the Technicon SMA 12/60 Analyzer. Correlation and comparison of results indicate that the Greiner Selective Analyzer performed better for three of the methods but worse for serum creatinine determination. The role of the analyser as a routine tool in the clinical laboratory was also evaluated during analyses of approximately 900 patient specimens.

Other features evaluated were analytical range of the six methods under study, the economics of operation, temperature control, and electrical and mechanical safety.
Notes on the Radioimmunoassay of Human Thyrotrophin
Authors: Wood P. J. , Smith Janet , Marks V.
Published: February 2014

This paper describes the use of screened transfusion plasma as a source of human thyroid stimulating hormone (h-TSH) free protein for standardization of a conventional “double antibody” h-TSH radioimmunoassay. Serum and plasma immunoreactive h-TSH levels have been shown to be stable for up to four days at 4°C and 25°C. A 37°C incubation procedure has been developed which gives an acceptable standard curve, but with some loss of “between batch” precision.
A Comparison of Gas-Liquid Chromatography and a Titration Method for the Determination of Plasma Non-Esterified Fatty Acid Levels during Pregnancy
Authors: Young Maureen , Gilmore Elizabeth A. , McDonald-Gibson R. G. , Elliott Jennifer A.
Published: February 2014

The level of plasma non-esterified fatty acids (NEFA) was measured by gas-liquid chromatography (GLC) and a titration method in 194 samples collected during pregnancy and from four days to 24 weeks post partum. Both techniques indicated a similar pattern of changes in plasma NEFA associated with pregnancy. The titration estimates of NEFA level were usually greater than those measured by GLC, and there was some suggestion that the disparity between the methods was increased at the end of pregnancy and was reduced at six weeks after delivery.
Rapid Micromethod for the Preparation of Leucocyte-Free Haemolysates for the Determination of Pyruvate Kinase and other Erythrocyte Enzymes
Authors: Westwood A.
Published: February 2014

In pyruvate kinase deficiency the high activity of the leucocyte isoenzyme may mask the erythrocyte defect. Separation of leucocytes from erythrocytes by the commonly used sedimentation or filtration procedures requires rather large volumes of blood, is time-consuming, and sometimes leaves an unsatisfactorily large proportion of leucocytes. In the present study at least 95% of leucocytes, measured with the lysosomal enzyme β-N-acetylhexosaminidase as a very sensitive marker for leucocyte lysis, were consistently removed by differential lysis of erythrocytes in hypotonic saline. Haemolysates suitable for erythrocyte enzyme assays can be prepared from very small quantities of capillary blood (10–100 μl) very rapidly, cheaply, and reproducibly by this method.
Observations on the Automated Calculation of Radioimmunoassay Results
Authors: Challand G. S. , Spencer Carole A. , Ratcliffe J. G.
Published: February 2014

Radioimmunoassay standard curves derived by four different automated calculation methods are compared with those derived manually for five assays of clinical importance (thyroxine, triiodothyronine, thyrotrophin, alphafetoprotein, and human growth hormone). The three curve fitting methods (linear or cubic regression on log x versus logit y, cubic regression on log x versus y) produced considerable distortion of the manually derived curves, which in some cases could have impaired the accuracy of an estimate in a clinical sample and altered the clinical interpretation. Distortion patterns varied with the particular antigen assayed and with experimental conditions. In contrast, a simple linear interpolation method produced little distortion and gave results which were close to those derived manually in each assay examined.
Accurate Measurement of Lecithin and Sphingomyelin after Ultra-rapid Chromatographic Separation
Authors: Cusick C. F.
Published: February 2014

The use of small sandwich chambers containing silica-gel-impregnated glass fibre sheets allows chromatographic separation of lecithin and sphingomyelin in 3 minutes, compared with 45 minutes on conventional silica gel media. Quantitation by measuring the areas of the phospholipid spots after staining with a molybdate stain or 8-anilino-1-naphthylamino sulphonic acid was found to be accurate and more convenient than densitometry. Although slight inaccuracies may be caused by lack of resolution from certain phospholipids, this was not found to be a problem in amniotic fluid analyses as they are either absent or present only in trace quantities. The speed of the technique makes it particularly useful for clinical purposes.
Hypocalcaemia: Differential Diagnosis and Investigation
Authors: Paterson C. R.
Published: February 2014

Hypocalcaemia accounts for many of the telephone inquiries made to the Department of Biochemical Medicine in Dundee. About half of these cases can be explained by hypoalbuminaemia; the causes of “true” hypocalcaemia are given in Table 1.

Chronic renal failure is probably the most frequent cause of hypocalcaemia in Britain. In the world as a whole it is likely that vitamin D deficiency, causing rickets in children and osteomalacia in adults, is the commonest cause of hypocalcaemia.
Hydrodynamic Radii versus Molecular Weights in Clearance Studies of Urine and Cerebrospinal Fluid
Authors: Felgenhauer K. , Renner E.
Published: February 2014

The protein permeabilities of the blood-cerebrospinal-fluid barrier and the blood-urine barrier are compared. In both instances the permeation rates of proteins can be better correlated to hydrodynamic radii than to molecular weights. The decreasing clearance rates of ceruloplasmin, IgG, and IgA reflect the hydrodynamic heterogeneity of these three proteins, which have similar weights. The IgM clearance rate appears too high, possibly owing to monomer IgM, other IgM fragments, selective transport, or active immunity, so its inclusion is not recommended in clearance studies.
Different Phenotypes for Phenylalanine Hydroxylase Deficiency
Authors: Güttler F. , Hansen G.
Published: February 2014

Abnormalities related to the hydroxylation of phenylalanine to tyrosine are classified into three phenotypes based on the amount of dietary phenylalanine tolerated to keep serum phenylalanine within therapeutic levels, i.e., 180–425 μmol/l (3–7 mg/100 ml): (1) Classical phenylketonuria (PKU) tolerating approximately 17% of a normal intake of phenylalanine or approximately 0.12 mmol per kg body weight; (2) mild PKU with a tolerance some 50% higher; and (3) persistent hyperphenylalaninaemia (HPA) with serum phenylalanine values within therapeutic levels on a daily intake of geqslant 0.7 mmol phenylalanine per kg body weight.

Oral phenylalanine loading was performed on 100 heterozygotes for these abnormalities and 33 normal homozygotes. The slope of the rise in serum tyrosine multiplied by the maximum serum tyrosine concentration over the maximum phenylalanine concentration was the most powerful discriminant (D/_s, 3.54; overlapping 2.4%). Three heterozygous phenotypes were distinguished by this discriminant, and a significant correlation was observed between the phenotypic combination of the parents and the phenotype of their affected child. In particular, parents of children with classical PKU were clearly distinguished from heterozygotes for the other two abnormalities.
Problems Associated with Measuring Sweat Chloride Concentration with an Ion-Specific Electrode
Authors: Price C. P. , Spencer K.
Published: February 2014

The measurement of sweat chloride concentration was investigated by using the Orion 417 skin chloride electrode. The effects of variation in pilocarpine concentration, iontophoresis period, and sweat collection period were also investigated. The results show that the sweat chloride concentration is directly related to the amount of sweat produced. When the amount of sweat collected falls below a certain level, there is an apparent increase in sweat chloride concentration. A procedure is recommended for the measurement of sweat chloride concentration which offers good precision (coefficient of variation 9.8%) and the minimum of inconvenience to the patient.
An Investigation into the Immunochemical Properties of the Isoenzymes of Human Alkaline Phosphatase
Authors: Abdullah J. Sh. , Gowland E.
Published: February 2014

A study was carried out to investigate the immunochemical properties of the alkaline phosphatases present in liver, placenta, intestine, and kidney. Butanol extracts of the tissues were examined by antigen-antibody crossed electrophoresis, and the immunoprecipitates formed by the enzymes were identified by use of a specific stain for alkaline phosphatase.

The results obtained revealed three immuno-chemical types of alkaline phosphatase, designated L, P, and PI respectively. The distribution of these enzymes among the tissues examined was as follows: type L was the only enzyme detected in liver extract and type P the only one detected in placental extract. The extracts of intestine and kidney both contained two isoenzymes, one of which was type L and the other type PI.
A Continuous Flow Method for the Estimation of Serum α—Amylase Activity
Authors: Carney J. A. , Osibeluwo S. A. , Clements J. A. , Jay R. F.
Published: February 2014

An automated assay for serum amylase is described. Using the AutoAnalyzer II the method employs, as substrate, a solution of dyed amylopectin which is commercially available (DyAmyl-L). After incubation of serum and substrate at 55°C, 1·0 mol/l KOH is introduced and the coloured products of enzymic hydrolysis are separated by dialysis against phosphate buffer. Absorbance is measured at 540 nm and the enzymic activity read from a standard curve obtained using calibration sera Versatol E and EN. The system provides accurate and reproducible measurement of serum amylase. The results obtained from assaying 100 ‘normal’ sera are compared with those using another method of α-amylase estimation.
Direct Measurement of cGMP in Blood Plasma and Urine by Radioimmunoassay
Authors: Wood P. J. , Marks V.
Published: February 2014

Antisera, raised against 2′-O-succinyl-cGMP conjugated to ovalbumin or kehole limpet haemocyanin, have been used to develop radioimmunoassays for the direct determination of urine and plasma cGMP levels. Details of these assays are presented, together with evidence for their validity.
Measurement of Serum Ferritin by Radioimmunoassay
Authors: Goldie D. J. , Thomas M. J.
Published: February 2014

Summary A direct radioimmunoassay for ferritin in serum is described in which Bolton and Hunter reagent is used to label ferritin. The detection limit of the assay is 150 pg; 95% reference ranges were found to be 12–200 μg/l for men and 5–76 μg/l for women. Ferritin concentrations in patients with iron deficiency anaemia were found to be uniformly low in subjects with uncomplicated iron deficiency but were normal or even raised in subjects with iron deficiency anaemia associated with malignant or inflammatory conditions.
Discrepancies in Thyroxine Measurement in Pregnancy between Radioimmunoassay and Competitive Protein Binding (Oxford StaT4)
Authors: Baird Sheila G. , Thomson J. E. , Thomson J. A. , Watson R. , Logue F. , Beastall G. H.
Published: February 2014

Summary The StaT4 test is a technically simple test of thyroxine measurement, which apparently gives results in good agreement with those derived by radioimmunoassay in most patients. In pregnancy, however, falsely low serum thyroxine values were found with the StaT4 test when compared with either a radioimmunoassay or the Thyopac-4 test. Detailed studies showed that the discrepancy resulted from the extraction technique used in the StaT4 test, which appears to allow the patient's thyroxine binding proteins to remain in the assay system. Similar method discrepancies were observed in other clinical conditions associated with elevated thyroxine binding globulin concentration. This study, as well as being of practical clinical importance, has implications for the design of competitive protein binding tests of thyroid function.
Total Urine Oestriol by a Modification of a Commercial Plasma Oestriol Kit
Authors: Seddon R. M. , Attwood E. C.
Published: February 2014

An adaptation of a radioimmunoassay for plasma oestriol for assaying urine oestriol is presented. The method has been shown to be precise, reliable, and directly comparable with the manual spectrophotometric technique for urine oestriol.
An Evaluation of a Simple Polyacrylamide Gel Electrophoresis System for Lipoproteins and its Use for the Characterisation of Hyperlipoproteinaemia
Authors: Foo Ying , Tickner T. R. , Cramp D. G.
Published: February 2014

The use of polyacrylamide gel electrophoresis as a screening procedure for the characterisation of hyperlipoproteinaemia is described. Sixty-one samples were investigated and classified by four different methods: (1) chemical profile derived from visual appearance and estimation of total cholesterol and triglyceride; (2) ‘SML’ profile by nephelometry; (3) electrophoresis on agarose gel; and (4) electrophoresis on polyacrylamide gel. Polyacrylamide gel electrophoresis showed the closest correlation with the chemical profile when compared with the other two methods. Polyacrylamide gel electrophoresis was found to be a rapid, reliable, and satisfactory procedure for plasma lipoprotein phenotyping.
A Rapid and Simple Method for the Quantification in Human Plasma of Tricyclic Antidepressant Drugs Taken in Overdose
Authors: Mitchell William D. , Webb Sarah F. , Padmore George R. A.
Published: February 2014

A rapid and simple extraction procedure followed by gas chromatography using a nitrogen detector is described for the analysis of amitriptyline, nortriptyline, imipramine, and desipramine in 100 μl plasma. No derivitisation of the drugs is required. Recoveries ranged from 93·7 to 104·6%. Within-batch precision and day-to-day variation showed coefficients of variation of less than 10% with the exception of desipramine, for which the day-to-day coefficient of variation was 15·2%. The method was developed to measure plasma concentrations in patients who had taken non-fatal and fatal overdoses of the drugs.
Evaluation of 3,4-Dinitrophenyl Tetra-N-Acetyl-β-Chitotetraoside as a Substrate for the Measurement of Lysozyme in Normal and Pathological Sera
Authors: Turner G. A. , Ghneim H. , Freeman J.
Published: February 2014

Lysozyme was measured using the synthetic substrate 3′,4-dinitrophenyl tetra- N-acetyl-β-chitotetraoside and the LKB Reaction Rate Analyser. This method has been evaluated by comparing levels obtained with serum samples from healthy individuals and patients with either cancer or inflammatory bowel disease with those obtained from the same specimens using a turbidimetric method. In terms of standard egg-white lysozyme, the colorimetric method gave much higher levels for all samples than the turbidimetric method; however, similar group differences were maintained. For individual serum specimens significant correlation between the two methods was found to occur only in the healthy group. Assay precision for the two methods was similar but the turbidimetric method could detect levels of lysozyme activity which were 10 times lower than those detected by the colorimetric method.
A Biochemical and Clinical Comparison of two Commercially Available Creatine Kinase Iso-Enzyme MB Assay Kits Suitable for use in the Routine Medical Laboratory
Authors: Surtees S. J. , Bastable M. D. , Gietzen T. W. , Model D. G. , Carmichael D. J. S. , Bordoli G. , Kidner P. H.
Published: February 2014

Two methods for the measurement of plasma creatine kinase MB (CK-MB) activity were compared for analytical performance, cost, practicality, and diagnostic correlation with clinical and electrocardiographic findings in patients admitted to the coronary care unit of a district general hospital. The methods were column chromatography and immunoinhibition. Both methods were found acceptable, and the method to be adopted would depend on the staff arrangements and resources available in the laboratory.
Calcium Metabolism in a Fatal Case of Sodium Fluoride Poisoning
Authors: Simpson Elliott , Rao LG Shankara , Evans Richard M , Wilkie William , Rodger J Christine , Lakhani Anil
Published: February 2014

A patient was admitted to a district general hospital within an hour of ingesting a fatal dose of sodium fluoride. The results of laboratory investigations, together with some in vitro findings, support the hypothesis that the hypocalcaemia of fluoride poisoning is the result of fluorapatite formation and not calcium fluoride precipitation, and that its persistence reflects the severity of the calcium deficit and not an inhibition of normal homeostatic mechanisms. It is suggested that the role of renal clearance of fluoride may be more important than had been realised hitherto.
A Simple Procedure for the Radioimmunoassay of 17α-Hydroxyprogesterone in Serum: Comparison with an Immunological Purification Technique
Authors: Davila Norma , Rudd BT , Morris R , Kandeel F , Bodden Jane , London DR
Published: February 2014

A simple radioimmunoassay for the measurement of 17α-hydroxyprogesterone in 0·1–0·25 ml serum is described. An antibody prepared against 17α-hydroxyprogesterone 3(O-carboxymethyl)-oxime-BSA as immunogen was used. A correlation of the 17α-hydroxyprogesterone concentration found in the serum of normal subjects and of patients with that obtained by a more complex immunological purification method was good (r = 0·924, p < 0·001). Accuracy, precision, and specificity were acceptable with the simple method. Normal values for infants, children, and adults have been established, and the individual concentrations of 17α-hydroxyprogesterone in the serum of patients with congenital adrenal hyperplasia were well separated from normal values.
A Dose Interpolation Routine for Multiple Dilutions in Radioimmunoassay
Authors: Laurence DJR , Kirkland Susan C , Ellison Morag L
Published: February 2014

A method of estimating doses from multiple dilutions of an unknown sample in radioimmunoassay is described. It uses a computer program to minimise the root mean square error about a standard curve. The confidence limits of the estimates were evaluated from the sum of squares error as a function of dose. An attached subroutine reported and suppressed points in the data set that showed unexpectedly large errors of fit. The program agreed well with an alternative point-by-point evaluation for most practical data but also responded robustly to errors at the limits of the assay curve. By studying patterns of point rejection, it is possible to build up information about the relation between the standard curve parameters and those in the unknown sets. The method is illustrated by studies of laboratory-based materials and by an assay of alphafetoprotein in samples of body fluids.
Quality of Commercially Available Controls in Laser Immunonephelometry
Authors: Shulman Gerald
Published: February 2014

Lack of accuracy in expressing concentrations of specific proteins in different lots of Hyland calibrating reference and quality control materials, supplied for the Hyland PDQ laser nephelometer, prompted an attempt to find alternative and more reliable calibrating materials available commercially. Laser grade (Atlantic Antibodies) and radial immunodiffusion grade materials (Behring Diagnostics) were evaluated in this study. Using Atlantic Antibodies' calibrator, only five of 11 specific proteins assayed in Atlantic control serum were within acceptable ranges; precision was less than that using Hyland materials of identical lots. Mean values for each of 10 of the same 11 specific proteins of Behring control plasma, assayed against Behring stabilised human serum, were within manufacturers' acceptable ranges; however, precision was less than that with Hyland materials from identical lots. Nine of the 11 specific proteins in a frozen serum pool sample, measured on the laser nephelometer, agreed well with results of the specific proteins measured by radial immunodiffusion, using the same Behring calibration and quality control. Only the Hyland materials were prediluted for use, which explains the greater precision that was obtained. Intercomparison of concentrations, as expressed by respective manufacturers, was largely unacceptable. Based on these results there is need, until satisfactory reagents become available, to standardise on one parent Hyland reference sample giving best precision and to calibrate all subsequent working standards against the parent reference.
Plasma Cortisone in Man: Its Determination, Physiological Variation, and Significance
Authors: Few J D , Cashmore G C
Published: February 2014

In a method for the simultaneous determination of cortisone, cortisol, and corticosterone, the extracted steroids are separated using paper chromatography and assayed by competitive protein binding. Evidence of the reliability of the method, particularly with respect to the determination of cortisone, is presented. Only trivial changes in cortisone level were detected in response to exercise, surgery, and ACTH, even though marked changes in cortisol level were simultaneously recorded. It is suggested that the inertia in plasma cortisone level may be related to its lesser degree of binding to plasma proteins, relative to cortisol, which would permit more rapid hepatic uptake and possible accumulation of a large extravascular pool of cortisone.
A Comparison of Urine Free Cortisol (RIA) with Cortisol Metabolites (GLC) for Detecting Increased Cortisol Secretion
Authors: Chambers R E , Willetts S R , Walters G
Published: February 2014

A comparison of the estimation of urine free cortisol by radioimmunoassay with the measurement of cortisol metabolites by gas-liquid chromatography (GLC) for detecting increased adrenal cortical activity has been made. Urine samples were examined from adults with normal or increased adrenal cortical function. Urine free cortisol showed a proportionately greater increase than cortisol metabolites when levels of cortisol were above twice normal, but both procedures led to the same qualitative conclusion about adrenal cortical activity. Their precision, ease of performance, assay time, and cost were similar. It is concluded that the greater sensitivity of the free cortisol does not warrant foregoing the additional information provided by the GLC method.
Radioimmunoassay of Thyroxine-Binding Globulin: Evaluation of a Kit and Diagnostic Application
Authors: Ahmed J , Smethurst P
Published: February 2014

Serum thyroxine-binding globulin (TBG) was measured by using a radioimmunoassay method. The within-batch coefficient of variation (CV) of the assay was 5 % or less at different TBG concentrations with a between-batch variation of less than 10%. The mean TBG concentration in hypothyroidism (28·5 ±6·7 mg/l) was significantly higher, and that in hyperthyroidism (22·3 ±3·5 mg/l) was significantly lower, than the euthyroid mean (25·4 ±6·9 mg/l). Acutely ill patients suffering from various non-thyroidal illnesses were found to have significantly low mean TBG (13·8 ± 4·3 mg/l). A group of women in late pregnancy had a higher mean value, as expected. Serum TBG level, however, was ineffective as a thyroid function test because of overlapping concentrations between groups. The derived index T4:TBG ratio was found to be superior to free thyroxine index (FTI) in many cases of acutely ill patients, pregnancy, and hereditary TBG abnormality. The 95% confidence limit for the ratio in euthyroids was 2·3 to 7·1. Serum TBG level with T4:TBG ratio is recommended as a replacement for the T3-uptake test and FTI.
Calibrant Solutions for Continuous-Flow Urate Analysis: Interference by Formaldehyde
Authors: Beetham R , Sanders P G
Published: February 2014

The use of formaldehyde to preserve aqueous urate calibration solutions has been recommended since 1913, but it interferes in some commonly used methods. At a pH below 8·5 formaldehyde affects the rate of dialysis of urate in Technicon AutoAnalyzer systems. This effect has been studied by variation of the pH at which dialysis takes place. The interference is attributed to the formation of pH-dependent addition products between uric acid and formaldehyde, which have been examined by thin-layer chromatography and mass spectrometry. Recovery experiments on protein-containing solutions show that a purely aqueous urate calibrant solution is satisfactory for use in AutoAnalyzer systems.
Units for Reporting the Results of Toxicological Measurements
Authors: Simpson D
Published: February 2014

A survey of hospital laboratories and current literature revealed that there is a considerable diversity of units employed for reporting the results of toxicological assays. Consideration is given to some of the problems and difficulties that arise from the use of SI units for reporting drug analyses, resulting from a lack of uniformity.
A New Fluorescence Method for Gamma-Glutamyltransferase Isoenzyme Demonstration
Authors: Rosalki S B , Nemesánszky E , Foo A Y
Published: February 2014

A new fluorescence method for demonstrating γ-glutamyltransferase isoenzymes using γ glutamyl-7-amino-4-methyl coumarin, a commercially available, non-carcinogenic substrate is described. The procedure can readily detect γ-glutamyltransferase isoenzymes in samples with total activity as low as 5 U/l at 30°C.
Ionic Fluoride: A Study of its Physiological Variation in Man
Authors: Cowell D C , Taylor W H
Published: February 2014

The serum ionic fluoride concentrations in 497 normal individuals, from areas with non-fluoridated water supplies, ranged from 0·25 to 2·20 μmol F−/l and were positively correlated with age (r = 0·31, p<0·001). Distribution of the data with age, coupled with the distribution of serum calcium with age, suggests a possible change in bone metabolism between 26 and 35 years of age. Serum fluoride levels vary with the time of day with a mean minimum value at 0800 and a mean peak value at 2200. Renal clearance studies gave fluoride ion clearances ranging from 19·5 to 44·0 ml/min and tubular reabsorption of fluoride ion ranging from 61·5 to 86·5%. After oral ingestion of 0·48 mmol sodium fluoride, peak serum levels occurred at 60 to 90 minutes; the peak levels were significantly higher in women than in men.
Measurement of Plasma Progesterone and its O-Methyloxime by Gas Chromatography—Nitrogen Detection
Authors: Frith R Gordon , Phillipou George
Published: February 2014

A routine method for the quantitation of plasma progesterone, using only 1 ml of sample, has been developed based on gas chromatography—nitrogen detection of the O-methyloxime derivative. Simple solvent extraction of progesterone from plasma using cyclohexane as solvent and medrogestone as internal standard allows measurement at the 3 nmol/l level, while the coefficient of variation at 16, 64, and 127 nmol/l progesterone is 14, 7·5, and 6·5% respectively. Comparison with a radioimmunoassay gave a linear regression equation of Y = 0·84 x + 1·4, Syx = 7·8, r = 0·9255 (n = 55).
On the Standardisation of the Direct Spectrophotometric Bilirubin Determination
Authors: Buster P , Vader H L , Vink C L J
Published: February 2014

The influence of different albumin solutions and of the molar bilirubin/albumin ratio on the bilirubin concentration determined by the method of Hertz et al was studied. There is good agreement between the true-bilirubin concentrations and those obtained by the Hertz method for bilirubin-HSA and bilirubin-serum solutions. Moreover the observed concentration is scarcely influenced by the molar ratio. Bilirubin standards in HSA-solutions can thus be used to standardise this method. Errors are introduced by preparing standards in BSA-solutions as the absorption spectrum of bilirubin-BSA is different from that of bilirubin-HSA.
Predictive Value of Derived Calcium Figures Based on the Measurement of Ionised Calcium
Authors: Gardner Mary D , Dryburgh Frances J , Fyffe J A , Jenkins A S
Published: February 2014

The algorithms used in this hospital to assess calcium status are calculated ionised serum calcium and the serum calcium concentration adjusted for albumin. In order to establish their clinical usefulness, they were compared with the ionised calcium concentration measured on the Nova 2 instrument in patients with various calcium and protein abnormalities. Good correlation was found between the measured and calculated values. The predictive values for the calculated results and for total serum calcium concentrations are presented. In this series, the derived values were useful in predicting the serum ionised calcium concentration of the patients studied.
Radioimmunoassay for Pancreatic Glucagon Based on Specific Derivatisation of the Hormone
Authors: Nooijen W J , Koppert P W
Published: February 2014

A specific glucagon antiserum was generated in rabbits using a derivatisation of the methionine residue in glucagon. A sensitive and specific assay for glucagon has been developed. Interference with the assay system by plasma factors was abolished by both extraction of plasma samples and the production of glucagon-free plasma for each individual.
A Rapid Method for Screening Urine Samples in Suspected Abuse of Cocaine
Authors: Hsu Lorna S F , Sharrard J I , Love C , Marrs T C
Published: February 2014

We report a quick method for the detection of cocaine and its major metabolites by thin-layer chromatography with confirmation by gas-liquid chromatography. Because it is possible to use the same chloroform-isopropanol extracts of urine in both procedures, the method is convenient for screening large numbers of urine samples.
Some Studies on the Polyethylene Glycol Turbidity Method for Detecting Immune Complexes in Serum
Authors: Kilpatrick D C , Weston J , Irvine W J
Published: February 2014

A rapid and simple method for detecting circulating immune complexes based on turbidity measurements following polyethylene glycol precipitation was studied with regard to its suitability as a routine assay in clinical laboratories. This method was found to have an acceptable degree of precision provided the temperature was carefully controlled. The mean value obtained with a group of 70 blood donors was 0·09 (SD 0·05) and the 90th percentile value was 0·16. There was no significant difference between values obtained from groups divided on the basis of age or sex. Of 70 diabetic sera assayed by the polyethylene glycol turbidity method, 20% gave positive values although only 10% were strongly positive. The corresponding figures for the solid phase Clq binding method were 15·7% and 14·3%, respectively. Correlation between the two methods was poor. It was concluded that although both methods have a similar likelihood of detecting immune complexes in randomly selected diabetics, it is probable that different immune complexes were being detected.
On the Transportability of Linear Discriminant Functions
Authors: Holland Martin R , Jacobs Anthony G
Published: February 2014

Different methods can give different results for the same analyte, and inconsistent answers may be obtained if such results are used in linear discriminant functions. This is an important factor to consider when transporting linear discriminant functions from one laboratory to another; the example of alkaline phosphatase activity and the differential diagnosis of hypercalcaemia has recently been given. This study shows that results obtained by the method recommended by the Scandinavian Committee on Enzymes for alkaline phosphatase may be used in the calculation of the discriminant functions used for the differential diagnosis of hypercalcaemia and considers other factors that may affect the discrimination. It is concluded that, with care, linear discriminant functions may be transported from one laboratory to another.
A Screening Method for Measuring Somatomedin B Protein Binding in Serum from Children with Growth Retardation
Authors: Rudd B T , Rayner P H W , Stafford Susan M , Halliday R
Published: February 2014

A simple method which uses 100 μl serum has been developed to measure the binding of somatomedin B (SMB) to protein in serum from normal children, adults, and patients with growth hormone deficiency. 125I-labelled SMB was used as binding ligand. The correlation between the binding of label by the proposed procedure and by an immunoelectrophoretic technique was acceptable (r=0·73; p <0·02). The mean percentage of label bound to protein in serum from patients with deficiencies of growth hormone or other trophic hormones was significantly (p<0·001) lower than that for controls. The physicochemical characteristics of a specific binding-protein suggested that a protein with low capacity (160 pmol/l) and low Ka (4·37 × 106 l/mol was present in serum, in addition to a high concentration of alpha globulin(s) which also bound 125I SMB.
Total over Free Thyroxine Ratio: Prediction of Thyroxine Binding Globulin
Authors: Bakker Andries J , Terpstra Ina
Published: February 2014

Both total thyroxine and free thyroxine concentrations are measured in the Immophase free thyroxine assay. These total and free thyroxine results allow a prediction of the accessory concentrations of thyroxine-binding globulin (TBG). Since abnormal concentrations of TBG often cause problems in the evaluation of thyroid function, we evaluated the possibility of predicting these abnormal values from total and free thyroxine results. Two ways of predicting abnormal concentrations of TBG were evaluated on statistical grounds. The first method, a simple total thyroxine/free thyroxine ratio, proved to be better than the second method, which corrected for the influence of the other thyroxine binding proteins (result: a calculated concentration of TBG). The total thyroxine/free thyroxine ratio predicts abnormally low TBG values, below a ratio of 4000 (certainty 45%) and abnormally high TBG values, above a ratio of 6400 (certainty 89%).
A Comparative Study of Free Thyroxine Estimations
Authors: Ross H A , Visser J W E , Der Kinderen P J , Tertoolen J F W , Thijssen J H H
Published: February 2014

Two commercial methods (Immophase, Corning and FT4, Lepetit) for the measurement of free thyroxine (FT4) in serum have been experimentally evaluated. Ease of handling and rapidity were satisfactory. Precision profiles showed intra-assay coefficients of variation not exceeding 5% over the entire measurement range (0–70 pmol/l) for both methods. Interassay coefficients of variation were below 8%. Assay results of both methods correlated well with those obtained with a symmetric dialysis method, with correlation coefficients of 0·95 for the Immophase and 0·93 for the Lepetit method and slopes not significantly different from unity. Comparison with this reference method did not give any indication of serious methodological error in either of the kits in spite of theoretical doubts with regard to one of them.
Precocious Pseudopuberty Due to a Rare Form of Congenital Adrenal Hyperplasia
Authors: Ratcliffe W A , McClure J P , Auld W H R , Honour J W , Fraser R , Ratcliffe J G
Published: February 2014

The biochemical investigation is described of a boy who presented with precocious puberty at the age of 3 years 9 months due to a rare form of congenital adrenal hyperplasia (CAH), steroid 11β-hydroxylase deficiency. Serum androgen levels were grossly elevated (17 hydroxyandrogens 10 nmol/l, androstenedione 129 nmol/l), 17 hydroxyprogesterone was modestly elevated (21 nmol/l), while serum gonadotrophins were low and testes were prepubertal in size. The major differential diagnosis was between an androgen-producing tumour and CAH. Initial serum and urine corticosteroid concentrations and their responses to dexamethasone were diagnostically misleading, later found to be due to lack of specificity of the radioimmunoassays and fluorimetric methods employed. Elevated basal plasma ACTH levels and suppression of androgen and ACTH levels by dexamethasone strongly suggested CAH. Definitive diagnosis of an 11β-hydroxylase defect was established by capillary column gas liquid chromatography of urine which demonstrated excess androgen and 11-deoxycortisol metabolites but no Cortisol metabolites. The diagnosis was confirmed by specific serum assays of 11-deoxycortisol, deoxycorticosterone, and Cortisol. The contribution of hormone assays and a protocol for their use in the diagnosis and monitoring of precocious puberty is discussed.
Determination of Total and Direct Bilirubin in Plasma by Means of a Bichromatic Method on a Centrifugal Analyser
Authors: Westwood A
Published: February 2014

A bichromatic method is described for the determination of both total and direct-reacting bilirubin using a miniature centrifugal analyser. Bilirubin was coupled with diazotised sulphanilic acid in strongly acidic reaction conditions, and sodium dodecyl sulphate was used as accelerator for the measurement of total bilirubin. The inclusion of dyphylline as a haem-binding agent greatly reduced interference, even in the presence of extreme haemolysis. The method was shown to be precise, to be more sensitive and less affected by haemolysis than alternative methods, and to allow the estimation of total and direct bilirubin within the same run.
A Column Chromatographic Method for the Removal from 2-Amino-2-Methyl-1-Propanol of Impurities That Inhibit Alkaline Phosphatase Activity
Authors: Derks H J G M , Tongeren V Borrias-Van , Bouma A M , Koedam J C
Published: February 2014

The selective removal from 2-amino-2-methyl-l-propanol solutions of impurities that inhibit alkaline phosphatase activity by means of Amberlite chromatography is described. The effects of buffer concentration, column dimensions, adsorbent type, and zinc sulphate addition were investigated. The method was found to improve greatly the quality of commercial 2-amino-2-methyl-1-propanol solutions and to have several advantages over alternative purification methods.