bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Analytical Aspects of the Immunochemical Determination of the Selectivity of Proteinuria
Authors: Beetham R. , Mills R. J. , Raine D. N. , White R. H. R. 
Published: February 2014

The selectivity of proteinuria has been determined from the relative clearances of α1-acid glycoprotein, albumin, transferrin and IgG in 190 children and adolescents. The precision of the determination of selectivity (C.V. = 3%) is greater than that of the individual protein clearances determined by a double immunodiffusion method (C.V. = 13–22%). Neither sample storage for a limited period nor concentrating the urine affects the selectivity value significantly; serial determinations in one patient for 24 h showed no diurnal variation. The effectiveness of selectivity in predicting the steroid response in the nephrotic syndrome was found to be slightly superior when determined from all four proteins than from transferrin and IgG alone. Inclusion of α2-macroglobulin relative clearance in the selectivity determination often significantly alters the value determined from the other four proteins alone. The reasons for this are discussed. Demonstration of α2M in urine which has not been concentrated, strongly suggests the presence of a structural glomerular lesion.
Recognition of the Mucopolysaccharidoses by Four Screening Tests, including a Refinement of the Albumin Turbidity Test, and Their Differentiation by Electrophoretic Separation of Urinary Glycosaminoglycans
Authors: Lewis P. W. , Raine D. N. , Kennedy J. F. 
Published: February 2014

Urinary excretion of mucopolysaccharides by normal subjects and patients with a mucopolysaccharidosis has been assessed by four screening tests including two quantitative determinations. Inclusion of a urine blank has been shown to reduce the number of false positive results given by the bovine albumin turbidity test. An electrophoretic technique has been developed and applied to urine concentrates. It has proved useful in the differential diagnosis of the mucopolysaccharidoses since four types are distinguished by characteristic glycosaminoglycan band patterns and another glycosaminoglycan pattern characterises two further types.
An Off-Line Clinical Chemistry Computer System
Authors: Vitek P. , Chiu S. , Healy M. J. R. , Lucas D. 
Published: February 2014

A low cost computer-based data processing system for a middle-size clinical chemistry laboratory is described. The emphasis is laid on organizing the laboratory work, minimizing the amount of clerical and arithmetic work undertaken by the technicians, and providing positive specimen identification. Details of specimens arriving for analysis are input to the computer, which allocates laboratory numbers and constructs worksheets for the various chemical tests. The results are also input (off-line) to the machine, which brings together results of different tests on one specimen and prints out properly identified reports. The accumulated results are transferred to a large remote computer and stored there on an archives file.
A Method for Quantitating Amylase and its Use in the Investigation of Various Body Fluids
Authors: Kipps Ann E. , Whitehead P. H. 
Published: February 2014

A plate-diffusion technique for the quantitative assay of amylase in body fluids is described which is dependent on the incorporation of a soluble amylopectin-dye complex into agar. The technique correlates well with other established amylase assays, and has a coefficient of variation of 1.45 for amylase levels within the normal range for serum. Normal levels of amylase in serum and urine are reported which agree with those recorded by previous workers, and in addition values of amylase in semen, saliva, and tears are quoted.
An Accurate Method for the Determination of Inorganic Phosphate in Serum
Authors: Pickup J. F. 
Published: February 2014

Cali's approach to accuracy is reviewed, and it is concluded that the main factor limiting its extension to analytes other than elements is the lack of suitable definitive methods of analysis. The work published on calcium, and work known to be under way on other elements, is based on the use of stable isotope dilution-mass spectrometry (I.D.M.S.) as the definitive technique. This paper outlines the theoretical considerations involved in extending I.D.M.S. to the determination of molecules; in particular, exact equations for the calibration graph obtained by I.D.M.S. are developed, and special cases of practical significance are defined. It is concluded that in theory there is no reason why accurate results should not be realised. The determination of isotope ratios is central to the technique of I.D.M.S. The means available for such measurements are discussed, and it is concluded that adequate precision can be achieved with standard equipment. To illustrate the application of I.D.M.S. to molecules the steps involved in an assay for inorganic phosphate are defined, and the protocol thus evolved is applied to specimens from the Wellcome Group Quality Control Programme. Although good correlation was found between I.D.M.S. results and the participants' mean results, there was a substantial bias. It is argued that this is a result of the difficulty of defining “inorganic phosphate” as a chemical entity. Some requirements for future work in this field are enumerated.
A Lipid and Lipoprotein Profile of Treated and Untreated Diabetics
Authors: Billimoria J. D. , Isaacs A. J. , Melki Kate 
Published: February 2014

A group of 149 diabetics and 98 healthy subjects without evidence of diabetes or ischaemic heart disease were studied. Untreated diabetics under 40 years old and 40 years of age and over showed statistically raised fasting serum turbidity, triglycerides, and raised β and pre-β lipoprotein levels but not raised cholesterol levels over the age and sex matched normal subjects. Further, some 63% of all diabetics showed a distinct split pre-β lipoprotein pattern as seen on polyacrylamide disc electrol-***phoresis as compared with 17% in the control group. Raised lecithin and phosphatidylethanolamine (PE) levels were found in male diabetics and raised PE levels in young diabetic women. In patients under treatment with insulin, chlorpropamide, or phenformin the diabetes was well controlled in most cases, but these patients did not have significantly lower lipid levels. Diabetics on a low carbohydrate diet showed improvement in triglycerides and pre-β lipoprotein levels, but β lipoproteins were not lowered. It is suggested that diabetics may benefit by the inclusion of clofibrate in the treatment.
Comparison of a Gas Chromatographic and Colorimetric Method for the Determination of Plasma Paracetamol
Authors: Chambers Robin E. , Jones Ken 
Published: February 2014

Plasma paracetamol levels have generally been determined either by gas chromatography (Stewart and Willis, 1975), which relies on complex equipment, or by spectrophotometry (Knepil, 1974), which can be time-consuming. The introduction by Glynn and Kendal (1975) of a simple colorimetric method based on the reaction of paracetamol with nitrous acid to give 2-nitro-4-acetamidophenol appears to have overcome these disadvantages, thereby providing a suitable procedure for the rapid measurement of plasma paracetamol in cases of overdose. The method was reported to be specific for paracetamol, no interference being caused either by the sulphate and glucuronide conjugates of paracetamol or by a large number of other commonly found drugs. This communication presents the results of a study in which plasma paracetamol levels determined by the colorimetric method were compared with those determined by an established gas chromatographic technique.
A Study of Factors Influencing Continuous Flow Kinetics: The Use of Serum Calcium Estimation as a Model
Authors: Spencer Kevin 
Published: February 2014

Previous studies of continuous flow kinetics have described an “AutoAnalyzer” peak in terms of two time constants, lag constant “a” and exponential constant “b”. Further investigations described here define some of the factors which affect these constants and hence peak shape and analytical performance. This communication outlines the application of this information to the development of an automated method for the determination of serum calcium, having a carry-over of less than 1 % and an analytical rate greater than 100/hour. The instaneous colour reaction, simple hydraulics, removal of the dialysis step, and the use of an integral debubbling flow cell have enabled small kinetic constants to be achieved. Over a period of three months' routine use between-batch coefficient of variation (C.V.) was 1.4%.
Development and Application of a Fully Automated Continuous Flow Radioimmunoassay System
Authors: Forrest Gordon C. 
Published: February 2014

A fully automated, continuous flow radioimmunoassay system is described. The antibodies are covalently linked to a magnetic cellulose solid phase and separation of bound and free antigen is achieved by applying an external electromagnetic field. The bound fraction, after washing, is counted in a flow-through gamma counter chamber. The system, employing AutoAnalyzer modules, is highly reproducible and allows assays to be performed without equilibrium being reached, and only 10 minutes' incubation time is required. The method is universally applicable to the assay of ligands, either protein, hormone, or drug, and for obtaining information about binding proteins. A new approach to the latter has been developed and is illustrated by a fully automated thyroid hormone uptake test which gives better discrimination between normal and pathological states than existing assays. The system operates at 30 samples/h and is characterised by the high precision, speed, and minimal carry-over which can be achieved.
Scottish Immunoassay Support Service Quality Control Scheme for Thyroxine, Triiodothyronine, and Digoxin Assays: Analysis of First 18 Months' Experience
Authors: Ratcliffe Wendy A. , Logue F. C. , Ratcliffe J. G. 
Published: February 2014

Summary Initial experience of the Scottish Immunoassay Support Service Quality Control scheme for thyroxine (T4), triiodothyronine (T3), and digoxin is analysed. For T4, radioimmunoassay (RIA) methods gave values close to the all-method mean. Competitive protein binding (CPB) kits gave values significantly higher (by 12%) in one and lower (by 10%) in another, probably due to the extraction of interfering substances such as non-esterified fatty acids or thyroid hormone binding proteins. The range of between-batch precision of individual laboratories was 10·8–47·5% (mean 17·8%) over the clinically relevant range. It was particularly poor at levels below the lower limit of the normal range. For T3 RIA, kit methods gave significantly higher values than independent methods although recovery of exogenous T3 was approximately quantitative with both. Cross reaction of T4 in T3 assays was insignificant. The range of between-batch precision for individual laboratories was 11·4–35·5% (mean 21·9%), and was poorest at levels of 1 nmol/l or less. For digoxin RIA, Lanoxitest γ gave significantly higher values than other methods, and over-recovered exogenous digoxin. The range of between-batch precision was 13·8–35·2% (mean 21·6%), and was poorest at levels of 1 nmol/l or less. The distribution of liquid human serum specimens at ambient temperature was satisfactory for quality control of T4, T3, and digoxin RIA but not for T4 by the Thyopac 4 method. Ox serum was unsuitable for certain T4 RIA methods.
Concentrations of Organic Acids in the Urine of Healthy Newborn Children
Authors: Alm J. , Hagenfeldt L. , Larsson A. 
Published: February 2014

Urine concentrations of organic acids were determined by a gas chromatographic technique in healthy, full-term neonates at the ages of 2 and 5 days. Significant reductions in the interindividual variation were obtained by relating the levels of organic acids to urine creatinine concentration or osmolality. Citrate was the predominant organic anion found. Urine concentrations of fumarate, 3-hydroxy-3-methylglutarate, adipate, and suberate decreased during the first week of life, and their concentrations were significantly intercorrelated. It is suggested that these findings reflect the predominantly fat-utilising, hyperketonaemic state during the first days of life. The urine concentrations of the aromatic end-products, p-hydroxyphenylacetate and hippurate, increased during the first week of life, probably as an effect of dietary factors. It is concluded that analysis of intermediary organic acids in urine could be of value in the assessment of the metabolic state in neonates.
Development and Validation of a Specific Radioimmunoassay for Somatostatin in Human Plasma
Authors: Penman Erica , Wass J. A. H. , Lund Alison , Lowry P. J. , Stewart Jennifer , Dawson A. M. , Besser G. M. , Rees Lesley H. 
Published: February 2014

Little is known about the factors controlling somatostatin secretion in man, and data are not available on the changes in circulating levels in various human physiological or pathophysiological states. This is mainly a consequence of the technical difficulties involved in measuring somatostatin in plasma. In the presence of plasma, binding of somatostatin tracer to antibody was consistently decreased by about 20%, and this could not be abolished by the addition of EDTA and aprotinin or by the use of specially prepared somatostatin-free plasma. Furthermore, in the presence of plasma, endogenous somatostatin does not dilute in parallel with synthetic cyclic somatostatin standard. We have, therefore, developed and validated a radioimmunoassay for somatostatin using prior extraction of the peptide onto leached silica glass. Tyrosine-11 somatostatin was iodinated using lactoperoxidase and purified on ODS silica. This method is superior to iodination using chloramine-T with CMC cellulose purification, and gives a highly purified preparation with a shelf-life of at least eight weeks. Using this tracer and a specific antiserum, the limit of sensitivity of the assay was 10 pg/ml, with an intra-assay coefficient of variation of 12% (n = 16) and inter-assay coefficient of variation of 15% (n = 10). Parallelism has been demonstrated between standard synthetic cyclic somatostatin and all extracted plasma samples. The mean recovery of exogenous somatostatin from plasma was 78%. The fasting level of immunoreactive somatostatin at 0900 hours in 40 normal subjects ranged from 17 to 81 pg/ml. Care is needed, however, when comparing these values with those obtained from other laboratories since standard preparations of somatostatin vary considerably in their immunopotency.
Quality Control of Radioimmunoassays for Proteins: The First Two and a Half Years of a National Scheme for Serum Growth Hormone Measurements
Authors: Hunter W. M. , McKenzie I. 
Published: February 2014

The philosophy and achievements of the first two and a half years of a national quality control scheme for serum growth hormone assays are described. Three serum samples were distributed to participating laboratories every two weeks. A computer-produced summary of the quality control results, which contained scattergrams and a statistical analysis, was returned to participants four weeks after despatch. The performance of 11 experienced (SAS) laboratories was found to fulfil the necessary accuracy criteria, and their results provided the ‘reference group mean’, which served as the target value. Gross positive bias exhibited by several laboratories was due to the use of assays with inadequate sensitivity, and this practice was eliminated during the first six months. During the course of the Scheme the average bias fell from 30 to 14%. With assays of adequate sensitivity, bias was almost invariably due to the misuse of standards. Median within-laboratory, between-batch precision (CV) improved from 23 to 15%. The best performers achieved between-batch CV of 7% which was 1·5 × their within-batch CV: the worst had three- to four-fold differences between within- and between-batch CV. Rudimentary quality control of interpretation was found to result in improvements in interpretation per se and also served to reinforce the desire to improve numerical agreement. A ‘recommended procedure’ based upon supplied first and second antibody, and a communal ‘reference range’ from 280 untreated acromegalics, both proved valuable.
Programming and Running Radioimmunoassay in the h-TSH Screening Procedure Using Dried Blood Spots and the NE1600 Gamma Counter on Line to the HP9815S Calculator
Authors: Edwards R W H , Hulse J A , Jackson Doreen , Spracklan Anne , Clayton Barbara E 
Published: February 2014

Screening for hypothyroidism has been achieved by seeking raised concentrations of thyroid stimulating hormone (h-TSH) in dried blood samples collected on absorbent paper from some 1700 newborn babies each week using double antibody radioimmunoassay and 125I-label counting on a NE1600 gamma counter linked to a HP9815S desk top calculator. Specificity, accuracy, and quality control of the assay have been investigated. The calculator programme stores all count, time, and calculated data and uses log-log function formation and third-power homoscedastic polynomial fit to the calibration data followed, if necessary, by elimination of outliers set at p= 0·5 %. Branching in the calculation procedure provides the ability to process sample data in subgroups, completely to reprocess data (including presentation in a form suitable for making a histogram plot), and to reset without loss of data in case of instrument or main power failure. Variance analysis was used to select the minimum duration of count (50 s), and it was demonstrated that homoscedasticity pertains in the regression calculation.
Effect of Platelets on Apparent Leucocyte Ascorbic Acid Content
Authors: Evans Richard M , Currie Lilias , Campbell Allan 
Published: February 2014

The leucocyte ascorbic acid content is widely used as a measure of tissue ascorbic acid status. Standard methods of analysis, however, isolate both leucocytes and platelets (buffy layer), with consequent overestimation, since platelet ascorbic acid is attributed to the leucocytes. Fourteen healthy individuals on ascorbic acid supplements and 11 patients on mega dose ascorbic acid therapy were studied. A significant correlation was demonstrated between the ‘leucocyte’ ascorbic acid content and the platelet: leucocyte ratio (r = 0·70, p<0·001). It is suggested that changes in the relative distribution of platelets and leucocytes in the blood will result in an apparent change in the ‘leucocyte’ ascorbic acid content regardless of any actual change in the ascorbic acid content of the cells.
Pre- and Post-Treatment Values of HDL Cholesterol and Total: HDL Cholesterol Ratio in Hyperlipoproteinaemic Subjects
Authors: Sale John K , Johnstone James H 
Published: February 2014

High-density lipoprotein (HDL) cholesterol, total cholesterol, and triglyceride concentrations were measured in fasting blood samples from 74 controls and 185 patients with untreated primary hyperlipoproteinaemia. The mean HDL cholesterol levels and the total cholesterol: HDL cholesterol ratios were significantly different between male and female subjects. Only patients with Fredrickson type IV hyperlipoproteinaemia had HDL cholesterol concentrations significantly lower than the controls, but all subjects with hyperlipoproteinaemia had total: HDL cholesterol ratios significantly higher than control values. Subsequent investigations were performed on 31 patients during treatment of the hyperlipoproteinaemia by diet alone or in combination with clofibrate. Responses were variable, but generally improvements in the concentrations of triglyceride and total cholesterol were accompanied by an unchanged or decreased total: HDL cholesterol ratio, although there was not necessarily an increase in the HDL cholesterol itself.
Gentamicin Assay: Comparison of an Adapted EMIT Method and an RIA Method
Authors: Dols Jan L S , Van Zanten Anton P 
Published: February 2014

The EMIT technique for gentamicin assay adapted to the Centrifichem-300 system was compared with an established RIA procedure. EMIT results correlated very well with the results obtained by the RIA method (r =0·976, N=48). For the adapted EMIT assay, the interassay coefficient of variation was 4–8 % and for the RIA method 6–14%. Several possible interfering agents were investigated, of which only carbenicillin showed interference in both assays. Our data indicate that the EMIT technique exhibits adequate precision and accuracy for routine gentamicin determinations.
Influence of Antisera, Purification Procedures, and Tracers on Validity of a Testosterone Radioimmunoassay
Authors: De Gomez Myriam S , Frei A , Vitins P , Cekan S Z 
Published: February 2014

The levels of testosterone in pooled plasma from men and from women were measured by radioimmunoassay. Testosterone was isolated from plasma either by ether extraction (direct procedure) or by chromatography of the ether extract (chromatographic procedure). Three different antisera (all raised against testosterone-3-oxime albumin) were employed. An additional variable was the use of two tracers, [3H] testosterone and [125I] histamine testosterone. The latter tracer was employed in both a freshly prepared form and two months after labelling. The old tracer was used both in a nonpurified and repurified form. The results were compared with those given by one of the antisera using the assay with chromatography. The validity of this assay was verified earlier using a test of radiochemical purity. In the statistical evaluation of the data, it was found that the assays of both plasma pools gave the same results as the validated assay, even with two other antisera, but only when the chromatographic purification was used. The direct assays gave significantly increased values for testosterone in the male plasma pool with one antiserum, and in the female plasma pool with all three antisera. It is concluded that those assays may be considered valid which give results statistically indistinguishable from those obtained by the valid assay. These were all chromatographic assays and, in the man, also two direct assays. The comparison of [3H] testosterone and [125I] histamine testosterone as tracers did not indicate any major differences in the validity of the assays. When the 125I-tracer was employed, a moderate (1 · 5–2 fold) increase of sensitivity was seen with all three antisera, and the antisera could be used in a 10–40 times higher dilution. Furthermore, it was possible to use [125I] histamine testosterone and obtain practically the same results after two months, whether repurified or not.
A Prospective Assessment of Tests of Fetoplacental Function
Authors: McDowell D R , Oliver R W A , Best F A 
Published: February 2014

Biochemical tests have been used to monitor fetoplacental function, mainly to detect impending fetal death in utero. The specimen-sampling patterns employed have not been adequate to detect all fetal deaths, and increasingly these tests have been used to detect low-birthweight babies who are at risk during the perinatal period. The purpose of this study was to investigate the three fetoplacental function tests, namely, serum total oestrogens, human placental lactogen, and cystine aminopeptidase activity under routine conditions to indicate whether these tests detected low-birthweight babies and, particularly, if they aided the clinical assessment of pregnancy. One hundred and sixty-six patients were studied; each set of results was classified as normal or abnormal and subsequently compared according to the outcome of pregnancy. In addition, a comparison was made between abnormal results where intervention was deemed necessary or unnecessary on clinical grounds. The conclusions reached were that these tests played a minor role in the assessment of pregnancy, at best being used to alert the obstetrician to an increased risk of an ‘abnormal birth.’