bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Urinary Free Cortisol Using the ACS:180 Serum Cortisol Chemiluminescent Immunoassay
Authors: Kennedy David M , Selby Colin , Lawson Nigel
Published: February 2014

Measurement of urinary free cortisol using the Bayer Automated Chemiluminescent System (ACS:180 PLUS) was evaluated and compared with an in-house extraction radioimmunoassay (RIA). Inter-assay coefficients of variation were acceptable, being respectively 5·3%, 4·8% and 3·8% at 141, 406 and 942 nmol/L ( n = 20) for the ACS direct assay and 19·4% and 12·1 % at 27 and 116 nmol/L with dichloromethane extraction ( n = 10). Using tritiated cortisol, mean extraction efficiency for the ACS extraction protocol was 89% compared with 104% for the RIA method ( n = 6, P < 0·001) and using urine spiked with ACS serum calibrator, extraction efficiency was only 76% (standard deviation 8·8%, n = 49) on the ACS. Urine spiked with cortisol dissolved in ethanol also gave significantly lower recoveries on the ACS for both direct and extraction methods compared with the RIA. Regression analysis of results from a mixture of control serum samples and samples from patients ( n = 93) showed good correlations between the direct and extraction ACS methods and the RIA extraction assay. The median concentration in 23 normal subjects and 95% reference intervals (nmol/24 h) were: ACS direct, 237 (135–505); ACS extraction, 91 (33–239); and RIA extraction, 146 (80–334). 5β-dihydrocortisol was the only major interferent in all assays. The ACS extraction assay showed acceptable performance and correlated well with the extraction RIA, although there was evidence of matrix-dependent effects causing low recovery.
Serum Apolipoprotein H and its Relationship to Blood Pressure, Serum Lipids, Fasting Plasma Glucose and Insulin in Normal Individuals
Authors: Crook M , Ch'ng S I , Lumb P , Reid F
Published: February 2014

Apolipoprotein H (apo H), also known as β2-glycoprotein I, has recently become of interest in the field of haemostasis. As apo H is elevated in diabetes mellitus and dyslipidaemia, we wished to test the hypothesis that serum apo H concentration was related to fasting plasma glucose and insulin as well as blood pressure, body mass index, hip/waist ratio and serum lipids in normal individuals.

Eighty-one healthy young individuals (46 females and 35 males) were studied. Their age was 20·7 ± 0·75 years. Serum apo H significantly correlated with fasting plasma glucose ( r=0·24, P=0·03) and serum LDL cholesterol ( r=0·30, P=0·006). In the females serum apo H significantly correlated with serum cholesterol concentration ( r=0·30, P=0·04) and in males with serum HDL cholesterol concentration ( r=0·35, P=0·04).

In multifactorial regression analysis for serum apo H and the other variables for the 81 subjects, only gender and fasting plasma glucose remained statistically significant in the model. Serum apo H concentrations would be expected to increase by 21.7mg/L for each single mmol/L increase in fasting plasma glucose (95% CI 2·3–41·2), P=0·029, and to increase by 17·0mg/L if the gender is male (95% CI 0·7–33·2), P=0·041.
Clinical Evaluation of the ACS:180 Cardiac Troponin I Assay
Authors: Collinson Paul O , Wiggins Nigel , Gaze David C
Published: February 2014

All patients admitted to the coronary care unit with suspected acute coronary syndromes were evaluated by serial electrocardiography and blood draws on admission and at 4 and 12h from admission. Diagnosis was based on conventional WHO criteria. Samples were measured for creatine kinase (CK), cardiac troponin T (cTnT), myoglobin, CK isoenzyme MB (CK-MB) and cardiac troponin I (cTnI). A set of samples from individuals undergoing extreme endurance training was also examined. Analytical imprecision was consistent with published quality goals. Samples were stable for cTnI under a range of storage conditions, including multiple freeze-thaw cycles. CK-MB, cTnI and cTnT were equally efficient for the diagnosis of acute myocardial infarction, irrespective of the final diagnostic criteria used. Both cTnI and cTnT were of equal efficiency in the identification of a high-risk subgroup of patients with unstable angina. Significant elevations of cTnI were not seen in an endurance-training group.
Biochemical Investigation of Foetal and Neonatal Thyroid Function Using the ACS-180SE Analyser: Clinical Application
Authors: Guibourdenche Jean , Noël Michèle , Chevenne Didier , Vuillard Edith , Voluménie Jean Luc , Polak Michel , Boissinot Christine , Porquet Dominique , Luton Dominique
Published: February 2014

Despite sonographic detection of foetal goitre, uncertainty persists in the initial diagnosis of thyrotoxicosis and hypothyroidism. The aim of this study was to establish foetal and neonatal iodothyronine and thyrotrophin reference values for the ACS-180SE analyser. From 22 to 36 weeks of gestation, median foetal serum free thyroxine (FT4) levels increased from 6·0 pmol/L to 14·3 pmol/L, while free triiodothyronine (FT3) levels increased from 0·7 pmoI/L to 1·9 pmol/L and mean thyrotrophin (TSH) levels remained stable (10·2±3·8 mU/L; n=33). At birth, concentrations were independent of gender and gestational age. Among the 10 cases of sonographically detected foetal goitre, serum TSH and FT4 were measured in five, showing hypothyroidism (3/5) or hyperthyroidism (2/5). Cord blood TSH levels reflected the efficacy of prenatal therapy. Measurement of foetal FT4 and TSH can be used to confirm foetal thyroid dysfunction, whereas treatment efficacy can be assessed sonographically and confirmed by measurement of TSH assay at birth.
Application of Solid-Phase Micro-Extraction Technology to Drug Screening and Identification
Authors: Mosaddegh Mohammad H , Richardson Thomas , Stoddart R W , McClure John
Published: February 2014

Benzodiazepines, tricyclic antidepressants and local anaesthetics are frequently involved in poisoning episodes and fatalities. A specific, sensitive and rapid procedure for identifying and quantifying such drugs in postmortem matrices has been developed using solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry. Very clean extracts were obtained in one step using SPME. The most commonly used fibre coatings were tested to select the best coating for SPME of the drugs. The appropriate fibre coating for most drugs was polyacrylate, followed by Carbowax-divinylbenzene. A Hewlett-Packard 5890 gas chromatograph in combination with a Trio 2000 mass spectrometer was used to analyse the samples. Temperature, time, pH and addition of sodium chloride were optimized to obtain consistent extraction. The between-day and within-day coefficients of variation were less than 16% and less than 6%, respectively.
Autoimmune Hypothyroidism Coexisting with a Pituitary Adenoma Secreting Thyroid-Stimulating Hormone, Prolactin and α-Subunit
Authors: Idiculla Jyothi M , Beckett Geoff , Statham Patrick F X , Ironside James W , Atkin Stephen L , Patrick Alan W.
Published: February 2014

A 44-year-old woman presented to her GP with excessive tiredness. She had positive thyroid microsomal and thyroglobulin autoantibodies and was found to have an elevated serum thyroid-stimulating hormone (TSH) concentration of 8.37 (normal = 0·15–3·5) mU/L and a low normal total thyroxine (T4) of 86 (reference range 60–145) nmol/L. She was rendered symptom free on a dose of 150μg of thyroxine per day. However, her TSH failed to return to normal, and following a further increase in her thyroxine dose she was referred to the endocrine clinic for further assessment. Her TSH at this stage was 14mU/L, free T4 (fT4) 28 (normal = 10–27) pmol/L and free T3 (fT3) 10 (normal = 4·3–7·6) pmol/L. She denied any problems with adherence to her medication. Her serum prolactin was elevated at 861 (normal = 60–390) mU/L. A pituitary tumour was suspected and an MRI scan showed a macroadenoma of the right lobe of the pituitary, extending into the suprasellar cistern. The tumour was resected trans-sphenoidally. Electron microscopy showed a dual population of neoplastic cells compatible with a thyrotroph cell and prolactin-secreting adenoma. Immunocytochemistry and cell culture studies confirmed the secretion of TSH, prolactin and α-subunit. Postoperative combined anterior pituitary function tests did not demonstrate any deficiency of anterior pituitary hormones. A repeat MRI scan showed no significant residual tumour; however, her serum TSH and prolactin levels remained high and she was given a course of pituitary irradiation. This case illustrates the difficulty of diagnosing a TSHoma when it coexists with autoimmune hypothyroidism. We believe the combination of pathologies reported here is unique.
Phaeochromocytoma with Normal Urinary Catecholamines: The Potential Value of Urinary Free Metadrenalines
Authors: Davidson D Fraser
Published: February 2014

Background

Normal urine catecholamine values in patients with phaeochromocytoma is an occasional finding and may lead to a missed diagnosis. Additional urinary free metadrenaline analysis may be of value in this situation.

Methods

In addition to vanillylmandelic acid, homovanillic acid and the catecholamines, urinary free normetadrenaline (fNMA) and free metadrenaline (fMA) were measured. This report describes six confirmed cases of phaeochromocytoma showing normal urinary catecholamine output and compares fMA results and tumour size with other confirmed cases where the urine catecholamines were increased.

Results

Urine catecholamines in these patients with, on average, smaller tumours, were all normal. Urinary fNMA and fMA were available on five patients, and were increased in three. The data suggest that, unlike the catecholamines, urinary fNMA and fMA could be a useful predictor of tumour size.

Conclusion

The inclusion of fNMA and fMA in the test profile is likely to be of additional benefit in tumour detection, particulariy when catecholamines or other metabolites are normal.
Influence of Glucuronosyl Bilirubin and (EZ)-Cyclobilirubin on Determination of Serum Unbound Bilirubin by UB-Analyser
Authors: Itoh Susumu , Kawada Kou , Kusaka Takashi , Yasuda Saneyuki , Okada Hitoshi , Imai Tadashi , Isobe Kenichi
Published: February 2014

Background

In the enzyme reaction for the determination of the unbound (free) bilirubin concentration by glucose oxidase and peroxidase, materials with low affinity for serum protein are reactive. The influence of these materials on the determination of serum unbound bilirubin was investigated.

Methods

Serum samples from patients with neonatal hyperbilirubinaemia were analysed by high-performance liquid chromatography for total glucuronosyl bilirubin concentration (TGC) and (E2)-cyclobilirubin concentration [(EZ)-C]. Based on these measurements, the samples were classified into three groups: group I [13 samples, TGC < 2 μmol/L and (EZ)-C < 2·5 μmol/L]; group II [four samples, TGC < 2 μmol/L and (EZ)-C ≥ 2·5 μmol/L]; and group III (five samples, TGC ≥ 2 μmol/L). The concentrations of total bilirubin and unbound bilirubin were measured in these same samples with a UB-analyser. When the absorbance at 460 nm was monitored, the decrease in absorbance was non-linear (concave curve). The degree of concavity was estimated (D15 value) as the deviation from linearity at 15 s.

Results

The D15 value was significantly higher in groups II and III than in group I. D15 value correlated significantly with TGC, (EZ)-C and unbound bilirubin concentration, and the unbound bilirubin concentration correlated significantly with TGC and (EZ)-C.

Conclusion

These results indicated that determination of serum unbound bilirubin concentration using the UB-analyser could be positively skewed by high concentrations of TGC and (EZ)-C.
An Improved Quantitative Assay of Glycogen in Erythrocytes
Authors: Miwa Ichitomo , Suzuki Sakiko
Published: February 2014

Background

Current methods for the quantitative determination of glycogen in erythrocytes are unsatisfactory.

Methods

Erythrocytes were deproteinized with perchloric acid either after haemolysing by freezing and thawing twice or without freezing and thawing, and the glycogen content was determined by an enzymatic method.

Results

Freezing and thawing resulted in a significantly higher glycogen content, and the recovery of added glycogen using this method was nearly 100%. The mean erythrocyte glycogen content in healthy volunteers ( n=17) was 69·5 μg/g haemoglobin, a value much higher than the previously reported values in healthy subjects.

Conclusion

Freezing and thawing improves the assay of erythrocyte glycogen.
Continuous Flow Electrometric Glucose Determination
Authors: Wilde C. E. , Sewell P.
Published: February 2014

A continuous flow system for the determination of glucose in blood or plasma using glucose oxidase is described. Oxygen uptake is measured by a Clarke electrode linked through an oxygen monitor and pH meter to a recorder. The omission of a peroxidase-chromogen step increases the specificity of the assay which gives very good correlation with the hexokinase-NADPH method.

The system has a high sensitivity which can be adjusted by changing the oxygen-nitrogen ratio of the segmenting gas. It is useful when measuring ‘true glucose’ in low concentration and gives a linear response within the range 0 to 200 mg/100 ml. The electrode response time limits the rate of analysis to 30 samples per hour if adequate precision is to be maintained.

The advantages of a closed continuous flow system over manual electrometric methods are discussed.
Genetic Counselling and Social Aspects of Prenatal and Newborn Population Screening
Authors: Cowie Valerie
Published: February 2014

Genetic counselling, with special reference to inherited metabolic disease is reviewed in the light of personal experience.
One-Dimensional Chromatography of Plasma in Manchester
Authors: Sardharwalla I. B. , Komrower G. M. , Bridge C. , Gordon D. B.
Published: February 2014

The Manchester experience of the amino acid screening programme is described. The Scriver test is simple and allows the detection of six amino acid disorders in one test. The cost is not great and the programme does not require large initial capital outlay. The number of cases detected exceeds expectation and cannot be explained.
A Practical, On-Line Computer System for the Clinical Chemistry Laboratory
Authors: Levy S. W.
Published: February 2014

A small economical computer system linked on-line to an SMA 12/60 and serving the needs of the biochemistry department is described. The system features mark-sense requisition cards for the input of patient indentification information and test requests, and pre-printed laboratory report forms designed to receive information such as: patient name, number and location; visual observations on the state of the specimen; SMA 12 results with automatic flags for borderline, abnormal and off-limit values; and flags for non-SMA tests requested (numerical values are later filled in by hand). The system also has an automatic alarm for detecting errors in sample sequencing and identification, and generates work lists, report forms bearing only patient identification, and non-SMA test-requests, statistical summaries of patient and control serum values, and a log of SMA 12 results for the day. The system has proved to be highly efficient and functions with virtually no down time and no major increase in operating costs to the department.
Use of the Barbiturate-Mercury Reaction in Clinical Laboratory ‘Screening’ for Barbiturate Poisoning
Authors: Watson D. , Dillion G.
Published: February 2014

The barbiturate-mercuric-diphenylcarbazone reaction of Lubran is reviewed. A micromethod for emergency serum barbiturate determination is described. Three significant improvements are linearity of colour reaction, the use of cellulose paper in the extraction and the use of tin-free dichloromethane as the extractant. Experiences with this method and with a commercial ‘kit’ method are recorded.
Urinary and Whole Blood Cadmium Concentrations in Renal Disease
Authors: Willden Elizabeth G.
Published: February 2014

A reliable method for the determination of cadmium in blood has been developed, and the concentrations in normal subjects and in patients with various types of renal failure determined. Dependency on, and variation with, age, sex and smoking habits in both health and disease have been investigated. The correlation of cadmium concentrations with renal diseases and their progress is postulated.
Plasma Testosterone Using Sephadex LH-20 and Saturation Analysis by Competitive Protein Binding
Authors: Lawrence Daphne M. , Swyer G. I.
Published: February 2014

A method Tor measuring plasma testosterone using separation on short columns of Sephadex LH-20 and competitive protein binding is described. This is more reliable and practicable than methods using paper or thin layer chromatography separation and Sephadex LH-20 can be re-used after washing.
A Versatile Radioimmunoassay for the Determination of Serum Oestriol in Pregnancy
Authors: Stafford J. E. H.
Published: February 2014

A versatile radioimmunoassay for serum oestriol in pregnancy has been developed which requires 10 μ| of serum (for total) or 50 μ| (for unconjugated).

Selection of the optimum conditions for the hydrolysis of serum oestriol conjugates, the isolation of free oestriol, the displacement of tritiated oestriol by cold oestriol and the separation of the free and bound fractions is described.

Total oestriol levels doubled between weeks 34 and 38 of normal pregnancy, very little change occurring in the mean level after the 38th week of gestation. In a random series of pregnancy sera there was a significant correlation between total and unconjugated oestriol.
Amniotic Fluid Bilirubin: A Comparison of Two Methods of Measurement
Authors: Aitken R. G.
Published: February 2014

The Liley technique used to obtain an indirect measure of amniotic fluid bilirubin is compared with a direct spectrophotometric bilirubin method which corrects for interference from pigments and turbidity. The relationship established enables results from the spectrophotometric method to be used in conjunction with the clinical interpretation chart originally described by Liley.
The Measurement of the Lecithin-Sphingomyelin Ratio of Amniotic Fluid after Thin-Layer Chromatography
Authors: Wagstaff T. I. , Whyley G. A. , Freedman G.
Published: February 2014

The estimation of the lecithin-sphingomyelin (L.S.) ratio on thin-layer chromatograms has been shown to vary depending upon the stain used to identify the phospholipids and the method employed to estimate the two components. The factors involved in causing these variations have been evaluated using standard phospholipid solutions and confirmed in clinical material. Staining with a phosphomolybdic acid stain followed by transmission densitometry was found to be an accurate and sensitive method for clinical purposes.
Ames Award Lecture 1973. Development of a Section-Bioassay for the Routine Assay of Corticotrophin
Authors: Alaghband-Zadeh J.
Published: February 2014

Although the new cytochemical assays of hormones have many important advantages over radioimmunoassay they are unlikely to be of use to clinical biochemists because of their remarkably low through-put. This has been overcome by using a new approach to bioassay in which the hormone is allowed to act on sections of the target organ. The many practical obstacles to this approach have been investigated and overcome. Consequently it is now possible to assay ACTH in many samples of plasma simultaneously and at a fraction of the time required by the previously described cytochemical methods, while yet retaining the remarkable sensitivity and accuracy of these methods.
The Assay of Urinary Thyroid Hormones for Assessing Thyroid Function
Authors: Chan Vivian
Published: February 2014

A competitive protein binding assay for thyroxine (T-4) and a radioimmunoassay for tri-iodothyronine (T-3) were applied to determine the urinary concentrations of these hormones. These measurements were shown to offer excellent diagnostic discrimination between euthyroid, hypothyroid, and hyperthyroid subjects. Urinary T-3 and T-4 levels were not affected by changes in the concentration of thyroxine binding globulin (TBG) or by changes in binding capacity; and therefore, remained normal during pregnancy, oestrogen, and phenytoin therapy. There was no significant circadian variation in urine T-3 excretion. Thus T-3 assays of overnight urine samples could be used in conjunction with dynamic test procedures, such as thyrotrophin (TSH) stimulation test, to enable the rapid assessment of the integrity of the hypothalamic-pituitary-thyroid axis.
A Revised Scheme for the Evaluation of Automatic Instruments for Use in Clinical Chemistry
Authors: Broughton P. M. G. , Gowenlock A. H. , McCormack J. J. , Neill D. W.
Published: February 2014

A revised scheme is described for evaluating automatic instruments used in clinical chemistry. Procedures are outlined for the assessment of mechanical and electrical features, and measurement of the accuracy and precision of individual units. Methods are given for the measurement of analytical precision, carryover, cross-contamination, accuracy, and linearity. The safety of equipment and methods of assessing costs are discussed, and the importance of subjective features is noted.
Comparison of Biochemical with Radiological Findings in Renal Osteodystrophy
Authors: Moorhead J. F. , Varghese Z. , Tatler G. L. V. , Baillod R. A. , Wills M. R.
Published: February 2014

In a group of 121 adult patients with end-stage chronic renal failure who had been undergoing maintenance haemodialysis for up to 10 years a number of biochemical variables have been measured and related to a set of objective radiological changes in the same patients. The changes in plasma calcium, magnesium, phosphate, total protein, and albumin concentration did not distinguish the patients who were grouped on a radiological basis. Plasma alkaline phosphatase activity increased with the severity of the radiological findings but did not provide a sensitive discriminatory index between the different radiological groups. Plasma hydroxyproline concentration was found to be more sensitive than plasma alkaline phosphatase activity in detecting a radiological abnormality in some of the patients.
Effect of Paracetamol on Uric Acid Determination
Authors: Wilding Peter , Heath David A.
Published: February 2014

The effect of paracetamol on uric acid determination using a phosphotungstate reduction method has been investigated. The results show that apparently raised values of serum uric acid may be reported in patients receiving therapeutic levels of this drug. Levels of serum uric acid were determined over a five-hour period in three patients who had received therapeutic doses of paracetamol. The assays of serum uric acid were performed by a method based on phosphotungstate reduction and by one employing uricase. The results illustrate the problems of using the former method for clinical purposes.
Evaluation of a Kit (Thyrolute) for the Combined Determination of Serum Total Thyroxine and Sequential Free Thyroxine Index using Sephadex G-25 and 125I-thyroxine
Authors: Howorth P. J. N. , McKerron C. G. , Marsden P.
Published: February 2014

A new kit (Thyrolute, Ames) for the combined determination of serum total thyroxine (T-4) and sequential free thyroxine index (F.T.I.) using Sephadex G-25 and 125I-thyroxine was evaluated in 136 patients and normal subjects. The T-4 determination was virtually identical to that used in the Ames Tetralute kit and had a similar accuracy and precision. The sequential F.T.I. was compared with a two-stage F.T.I. The two F.T.I.s showed highly significant correlations in the various groups of patients except euthyroid women with raised thyroxine-binding globulin (TBG) (pregnant or oral contraceptive). The overlap found for the sequential F.T.I. between euthyroid, hypothyroid, and thyrotoxic patients was slightly inferior (9%) to that found with the two-stage F.T.I. (6%), but its diagnostic success rate was higher than that of the serum T-4 determination alone.

Serial observations of serum T-4 and sequential F.T.I. were also made on eight patients receiving carbimazole therapy for hyperthyroidism. The sequential F.T.I. showed complete parallelism with serum T-4 regardless of thyroid status, so that it was of no practical value in these patients. It was concluded that the sequential F.T.I kit would be of most value in the smaller hospital laboratory lacking facilities for the radioimmunoassay of thyroid hormones and thyroid stimulating hormone.
Assay of Cortisol in Serum by Competitive Protein Binding without Solvent Extraction
Authors: Morris R. , Holder G.
Published: February 2014

A method for the determination of serum cortisol by competitive protein binding is proposed in which solvent extraction is replaced by heat inactivation.

Results obtained by the new technique correlate well with those obtained by solvent extraction.

A saving in manipulative time and glassware is effected when the method is applied in a routine assay.
A Potential Screening Test for Elevated Serum Amylase Levels: Preliminary Communication
Authors: Kipps Ann E. , Whitehead P. H. , Alberti K. G. M. M. , Weeks B. F.
Published: February 2014

The use of an amylase-sensitive paper in a screening test for elevated serum amylase levels is described. The paper requires some modification before it can be used as a quantitative amylase assay, but even in its present form it will reliably identify samples with raised amylase levels. In tests with sera received routinely for amylase assay the paper characterised 80% of samples as Normal. Quantitative amylase assay confirmed the results, and thus, even with the present paper, if only the MEDIUM or HIGH sera were sent to the laboratory for full biochemical analysis there would be an 80% decrease in requests.
Reliability of Plasma Cortisol Determination by a Simple Competitive Protein Binding Method
Authors: Cashmore G. C. , Few J. D. , Fowles Christine H.
Published: February 2014

The method investigated used [3H] cortisol as the ligand, diluted human plasma as the binding protein, and florisil to separate free and bound cortisol. The precision and specificity were found to be adequate for routine use. The effects of such factors as delay in separation of plasma, storage of plasma, provenance of the binding protein, venepuncture, and venous occlusion have been studied. The extent and significance of short term, inter-daily, and longer term variation in plasma cortisol level are discussed.
Simultaneous Radioimmunoassay of Thyroid Hormones in Unextracted Serum
Authors: Haynes S. P. , Goldie D. J.
Published: February 2014

A combined radioimmunoassay for the two thyroid hormones is described which uses 125iodine labelled triiodothyronine and 131iodine labelled thyroxine. The assay employs a double antibody separation technique and is suitable for use with unextracted serum. The results from the simultaneous assay compare very well with the results obtained in the single assays, and the discriminating power and precision of the simultaneous assay is at least as good as in the single assays.
Some Physiological Factors Affecting the Binding of Cortisol by Human Plasma Proteins
Authors: Few J. D. , Haspineall J. R.
Published: February 2014

Steady-state gel filtration has been used to study the binding of cortisol to human plasma proteins in vitro. Raising the temperature from 37°C to 41°C results in the mean proportion of free (non-protein-bound) cortisol rising approximately from 7% to 11%. Addition of cortisol to plasma ≡ 275 nmol/l) also increased the proportion of free cortisol by approximately 50%. Cortisone is less strongly bound to plasma proteins than cortisol. The mean values (±S.D.) for five samples were free cortisol 8.4 ± 1.1% and free cortisone 26.0±3.8%.
Paracetamol Estimation: Comparison of a Quick Colorimetric Method with a Standard Spectrophotometric Method
Authors: Wiener K.
Published: February 2014

A new colorimetric method for the estimation of plasma paracetamol was slightly modified and compared with a standard spectrophotometric method. Good correlation and no significant difference was found between results by the two procedures. Precision, accuracy, and recovery by the colorimetric method were acceptable. Several drugs were tested for interference in the colorimetric method. Some sulphonamide preparations potentially interfere. On the other hand it is less susceptible than the spectrophotometric method to interference by certain other drugs.

The speed and simplicity of the colorimetric method, together with its satisfactory performance, make it a worthwhile alternative to the spectrophotometric procedure.
Influence of Reagent Quality and Reaction Conditions on the Determination of Serum Albumin by the Bromcresol Green Dye-Binding Method
Authors: Spencer K. , Price C. P.
Published: February 2014

In an age of reference methodologies and sophisticated quality control techniques it is surprising that so little attention is paid to the quality of the reagents that are used. This paper reports on an investigation of the bromcresol green dye-binding procedure for the estimation of serum albumin in which particular attention has been paid to changes in the reagent components that contribute to the performance of the method. It has been shown that detailed attention to the quality control of the reagents can improve the precision and interlaboratory comparison in the estimation of serum albumin.
A Simple Radioimmunoassay for Plasma Cortisol: Comparison with the Fluorimetric Method of Determination
Authors: Carr P. J. , Millar R. P. , Crowley H.
Published: February 2014

A quick and simple method for the radioimmunoassay of plasma cortisol is described. The mean morning plasma cortisol concentration in 43 normal subjects was 9.8 ± 3.1 (S.D.) μg/100 ml with a range of 5.0–19.5 μg/100 ml. Mean midnight concentration in 24 normal subjects was 4.3 ± 2.3 (S.D.) μg/100 ml with a range of 1.4–9.6 μg/100 ml. When compared with the fluorimetric method the mean results by radioimmunoassay of 154 routine specimens were 23% lower. In samples from unstimulated patients, regression analysis of results obtained by the two methods gave a correlation coefficient (r) of 0.93, regression line slope of 1.1, and intercept of 1.4 μg. Mean radioimmunoassay results were 15% lower. When plasma cortisol concentration was above the normal range (>30 μg/100 ml) the regression line slope was 0.87, the intercept 17.9 μg, r = 0.87 and mean radioimmunoassay results were 37% lower. Plasma cortisol concentration in patients after insulin or Synacthen stimulation exhibited similar responses when measured by either method. Plasma cortisol concentration in normal subjects given metyrapone was lower when measured by radioimmunoassay (mean ± S.D. = 8.7 ± 2.7 μg/100 ml) than when measured by fluorimetry (18.5 ± 10.8 μg/100 ml). The diagnostic usefulness of the two methods, ease of assay, and costs are compared.
Enzyme Multiplied Immunoassay of Phenobarbital by LKB Reaction Rate Analyser: A Comparison with Analysis by Gas-Liquid Chromatography
Authors: Belfield Alan , Duncan Anne M. , Reavey P. C.
Published: February 2014

A procedure for the enzyme multiplied immunoassay of phenobarbital using the LKB Reaction Rate Analyser is described. The temperature optimum, linearity, specificity, and precision of the assay are reported. A highly significant correlation coefficient is obtained when the technique is compared with gas-liquid chromatography by analysing human sera containing a range of phenobarbital levels.
A Simplified Procedure for the Isolation of Bile Acids from Serum Based on a Batch Extraction with the Non-Ionic Resin—Amberlite XAD-7
Authors: Barnes S. , Chitranukroh A.
Published: February 2014

A simple and reproducible method using the non-ionic resin, Amberlite XAD-7, for the isolation of bile acids from serum by a batch procedure is described. Recoveries were greater than 95% for the non-sulphated bile acids and greater than 70% for the sulphate esters of bile acids. By using 1 g of resin, recoveries were independent of the mass (0.1–5 μmol) of the bile acid present. Up to 35 samples a day can be extracted without requiring dedication of the operator. When serum extracts were analysed by the 3α-hydroxysteroid dehydrogenase procedure for estimation of bile acids, virtually all the background fluorescence was eliminated. These extracts were also suitable for gas liquid chromatography, thin layer chromatography, and radioimmunoassay.
Automated Fluoride Ion Determination
Authors: Cowell David C.
Published: February 2014

An automated method is described, using standard continuous flow techniques, for the determination of urine fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in urine, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 83 to 90%; in-batch precision is between 0·9 and 1·6% and carryover 2·5% or less.
Automated Fluoride Ion Determination
Authors: Cowell David C.
Published: February 2014

A method is described, using standard continuous flow techniques, for the automated determination of serum fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in serum, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 86·6–98·5%, in-batch precision is 1·0–6·1%, between-batch precision 5·5%, with carryover of −2·99%.
A Long-Term Evaluation of the Centrifichem Centrifugal Microanalyser during Routine Use in the Clinical Biochemistry Laboratory
Authors: Fleetwood J. A. , Latner A. L. , Marriner A. , Skillen A. W. , Smith P. A.
Published: February 2014

The CentrifiChem centrifugal microanalyser (model 300) has been used routinely in this laboratory for two years. Its reliability for performing total bilirubin, aspartate aminotransferase alkaline phosphatase and γ-glutamyl transferase analyses during this time is reported, using methods modified in a preliminary study. Accuracy of the analyses has been assessed by comparing the results with those from other analytical systems and by using commercial control sera. Determinations have been made for within-batch, between-day (20 days), and long term (100 weeks) precision. Other aspects evaluated were the range over which methods were linear and the cost of operation.
Blood Sampling Technique for Lactate and Pyruvate Estimation in Children
Authors: Kollée L. A. A. , Willems J. L. , De Kort A. F. M. , Monnens L. A. H. , Trijbels J. M. F.
Published: February 2014

The effects of stress and muscular movements caused by direct venepuncture and of venestasis on the lactate and pyruvate levels in children have been examined. Direct venepuncture and venestasis significantly influence the obtained values. To measure reliable values for pyruvate and lactate in blood of children it seems advisable to insert an indwelling intravenous cannula. After 45 min of rest in bed the blood sample can be obtained.
Comparison of Maternal Serum and Urinary Oestrogen Determinations as Indicators of Fetal Well-Being
Authors: Giorgi Eleonora P. , Gore Marion B. R. , Tye Gillian M.
Published: February 2014

Serum oestrogen concentration and urinary oestrogen excretion were measured in 134 women in the last trimester of pregnancy. An automated fluorimetric method was used for urinary oestrogens and a radioimmunoassay which measures both free and conjugated oestrogens, with the exception of sulphates, was employed for serum. Pregnancies were classified into a ‘normal’ or ‘abnormal’ group according to the clinical state of the baby at birth. The range of values for both serum and urinary oestrogens was wide at each stage of gestation and the mean values in the two groups were not significantly different. It was concluded that for a valid indication of fetal well-being serial determinations were essential, and that serum and urinary oestrogens were of comparable predictive value. Expressing the urinary results in terms of creatinine excretion did not improve their predictive value.
A Comparative Study of Commercial Human and Bovine Albumin Preparations
Authors: Farrance I. , Dennis P. M. , Gibson Barbara J. , Biegler Beryl
Published: February 2014

A number of commercial human and bovine albumin preparations were compared using seven assay procedures, to assess their suitability as reference materials for albumin and total protein assays. The results indicate that before a particular commercial albumin preparation can be used for standardisation purposes, its suitability should be checked in several assay systems which measure a different functional aspect of the protein molecule. The measurement of extinction coefficient in the range 278–280 nm does not appear to be a valid measure of protein content if the albumin preparation is to be used for standardisation of immunochemical or dye-binding assays.
A Chemiluminescent Effect Encountered in the Liquid Scintillation Counting of 32P phosphate
Authors: Bell T. K. , Lappin T. R. J.
Published: February 2014

During the course of a kinetic enzyme study of bisphosphoglyceromutase (EC 2.7.5.4.) a chemiluminescent effect was encountered in the liquid scintillation counting of the β-emission from 32Pi. A method is described for overcoming the effect, thereby permitting the accurate determination of the radioactive compounds. It is important to check for chemiluminescent effects early in the development of new procedures that involve liquid scintillation counting.
AN Evaluation of the Hyland Laser Nephelometer PDQ System for the Measurement of Immunoglobulins
Authors: Whicher J. T. , Perry D. E. , Hobbs J. R.
Published: February 2014

Summary The Hyland laser nephelometer PDQ system for the assay of specific proteins is described. The results of evaluating the system to measure immunoglobulins IgA, IgG, and IgM are summarised. Within-batch and between-batch precision, accuracy, reliability, and safety are discussed. This instrument represents an important development in the immunochemical assay of proteins in clinical medicine. The speed, precision, and convenience of this new generation of discrete nephelometric analysers make such systems attractive to the clinical chemist.
An Improved Automated Method for the Analysis of Inorganic Phosphate without Dialysis
Authors: Roberts N. B.
Published: February 2014

Summary A procedure is described for automating the analysis of inorganic phosphate in physiological media without dialysis. Sodium dodecyl sulphate is used to maintain protein solubility during the analysis. Sample analysis was measured at 60 and 90 samples an hour. The inorganic phosphate results obtained for a series of human plasma and for various internal control sera by non-dialysis and dialysis showed good agreement.
Identification of an Unusual Gamma Counter Fault Using Trigg's Technique for Trend Detection
Authors: Challand G. S. , Cox Lorna
Published: February 2014

Summary A simultaneous deterioration in performance of several radioimmunoassays suggested that equipment was malfunctioning. Replicate counts from an automated gamma counter showed unacceptable variation during a 24-hour period; this variation was detected using Trigg's technique, a sensitive method for trend analysis, and was not identified by the usual laboratory testing procedures. A defective capacitor was found in the voltage stabilisation unit in the gamma counter, which probably made it responsive to small variations in the power supply to the laboratory. It is suggested that the analysis of replicate counts using Trigg's technique is a valuable test of gamma counter function which should become routine.
A Simple Method for Measuring Urinary Meglumine Ioglycamide† Concentrations
Authors: Spencer J. D. , Albutt Eileen C.
Published: February 2014

Summary A new method for measuring the urinary concentration of meglumine ioglycamide, a radiological contrast agent, is described. The contrast is precipitated with acid, redissolved, and estimated by ultraviolet spectrophotometry.
Excretory Patterns of Urinary Free 11-Hydroxycortico-Steroids and Total Oestrogens Throughout the Normal Menstrual Cycle
Authors: Walker M. S. , McGilp I.
Published: February 2014

Summary The excretion of urinary free 11-hydroxycorticosteroids and total oestrogens was studied daily in morning urine specimens throughout the menstrual cycle of six normal women (age range 18–24 years). The follicular phase of the cycle was characterised by apparently random fluctuations in the excretion of urinary free corticosteroids. However, after the mid-cycle oestrogen peak there occurred a significant drop in corticosteroid excretion, which then rose to a peak eight to 10 days after ovulation and was synchronous with the second oestrogen peak during the luteal phase.
Evaluation of a Kit for the Colorimetric Determination of Inorganic Phosphate
Authors: Fraser C. G. , Peake M. J.
Published: February 2014

An evaluation of a colorimetric kit method for the determination of inorganic phosphate (Pierce Phosphorus Auto/Stat Kit) is described. The within-batch and between-batch precisions were shown to fulfil current criteria, and recovery experiments, linearity studies, analyses of quality control materials, and studies of possible interfering substances evidenced good accuracy. Comparison of the results obtained on samples from patients with those obtained by the vanadate/molybdate continuous-flow method showed that the test method had a comparative positive bias. The use of a calibration reference serum as standard is recommended. The kit method is technically simple, requiring no protein precipitation, and analyses can be performed rapidly.
Estimation of Alcohol Intake from Laboratory Results
Authors: Whitfield J. B. , Hensley W. J. , Bryden D. , Gallagher H.
Published: February 2014

Subjects with abnormalities in a number of laboratory tests were shown to have higher than usual probabilities of being heavy drinkers. Quantitative estimates have been made of the probabilities of heavy drinking from the results of the following tests: gamma-glutamyl transpeptidase, mean corpuscular volume, uric acid, triglyceride, and aspartate aminotransferase. In men, but not in women, there was a clear increase in this probability with increasing test results for these five tests, which may prove useful in the detection of individuals who are at risk from their drinking habits.
Automation of the Turbidimetric Determination of Serum Lipase
Authors: Puukka M. , Puukka Raija
Published: February 2014

A turbidimetric procedure for the determination of serum lipase activity has been adapted for use on a System Olli 3000 analyser. In this automated procedure 50 μl of serum and standard sample, and a buffer solution, are pipetted into disposable cuvettes in the measurement block. The block is then preincubated for 15 minutes at 37°C, and after simultaneous addition of the olive oil emulsion, the absorbances of the cuvettes are recorded simultaneously for two minutes at 405 nm. Using the program ‘block standards’ for the calibration of the method the results are ready in graphic form and expressed as U/l within about five minutes of the addition of the olive oil. A total of 60 patient sera can be analysed in half an hour.

The method is linear up to at least 1000 U/l, and the reference values are between 11 and 140 U/l. A comparison of the method with the modification of the Cherry-Crandall titrimetric method gives a value of 0·87 for the correlation coefficient and the regression equation y = 0·97x + 12 (n = 191). Within-run precision (CV) for sera with mean enzyme activities of 149 and 354 U/l was found to be 4·2% and 3·4%, respectively (n = 20), and day-to-day precision 5·0% (mean activity = 339 U/l, n = 18).
High-Density Lipoprotein, Lipid, and Carbohydrate Metabolism during Increasing Fitness
Authors: Moore R. A. , Penfold W. A. F. , Simpson R. D. , Simpson R. W. , Mann J. I. , Turner R. C.
Published: February 2014

Eleven unfit bank executives in sedentary employment exercised daily for 10 weeks according to the Canadian Air-Force 5BX Exercise Programme. Over this period no changes were observed in the glucose or insulin responses to a standard breakfast or to intravenous glucose, or in the glucose response to intravenous insulin. There was a significant reduction in high-density-lipoprotein cholesterol, but total plasma triglyceride and cholesterol levels were unaffected by exercise.
A Rapid Kinetic Assay for Glucose using Glucose Dehydrogenase
Authors: Price C. P. , Spencer K.
Published: February 2014

An automated kinetic assay for the determination of glucose in blood is described. The method employs the enzyme glucose dehydrogenase in the presence of mutarotase, with nicotinamide adenine dinucleotide as hydrogen acceptor. The analytical parameters of the method are determined and the flexibility of the method in relation to sample volume and sensitivity is discussed. Finally, the method is compared with automated glucose oxidase and hexokinase procedures.
A New Aid in the Assessment of Pancreatic Function
Authors: Stagg B. H. , Wood T. P.
Published: February 2014

This review describes the development and application of a novel test to determine levels of human immunoreactive trypsin, an enzyme produced solely by the pancreas, in biological fluids. Being organ-specific, the assay of immunoreactive trypsin should be an ideal marker of pancreatic function, and this is supported by the results of a number of clinical and research investigations. Use of this assay in studies of chronic pancreatitis, juvenile-onset diabetes, and cystic fibrosis has yielded much valuable data, and it is expected that further research will lead to an improved understanding of these and other conditions associated with the pancreas in health and disease.
Colorimetric Method for Determination of Urinary Methylmalonic Acid
Authors: Westwood A. , Taylor W. , Davies G.
Published: February 2014

The colorimetric method for the determination of methylmalonic acid by coupling with diazotised p-nitroaniline has been re-examined. Extraction of the diazotised product into amyl alcohol and tetra-methyl ammonium hydroxide considerably increases its stability and sensitivity and reduces background absorbance. Preliminary solvent extraction and ion-exchange chromatography are desirable but can be accomplished simply and quickly using very small quantities of urine. In this form, the method is very reliable and gives recoveries of about 95% and a coefficient of variation of about 7%.
Hydroxyproline Metabolism in Type II Hyperprolinaemia
Authors: Similä S.
Published: February 2014

Hydroxyproline metabolism was studied in two patients with type II hyperprolinaemia (HP II) using oral loadings of hydroxyproline or hydroxyproline-ornithine. Δ1-pyrroline-3-hydroxy-5-carboxylic acid (3 OH-PC) and Δ1-pyrroline-5-carboxylic acid (PC) were identified in the urine. The urinary excretion of both 3-OH-PC and PC increased in HP II patients but not in healthy controls during oral loading of hydroxyproline and hydroxyproline-ornithine.

The plasma level of proline in patients with HP II is very high but the hydroxyproline concentration is normal or only slightly increased. Therefore one can assume that hydroxyproline is converted to pyrrole-2-carboxylic acid, which is excreted in urine as a glycine conjugate.

In this study it was demonstrated that the highly elevated plasma level of proline in one of the patients with HP II decreased greatly after hydroxyproline-ornithine load; this change was followed by a 40-fold rise in urinary excretion of proline.
Diagnosis of Red Cell G-6-PD Deficiency in a Chinese Neonate
Authors: McCulloch J. C.
Published: February 2014

In the neonatal period, a red cell deficiency of glucose-6-phosphate dehydrogenase (G-6-PD) may result in jaundice, the severity of which will vary between patients. Diagnosis of this inborn error of metabolism presents a problem if there is a large number of young enzyme-rich red cells in circulation, and this paper details the technique used to confirm a red cell deficiency of G-6-PD in a neonate.