INTERNATIONAL REFERENCE PREPARATION OF HUMAN PROLACTIN FOR IMMUNOASSAY: DEFINITION OF THE INTERNATIONAL UNIT, REPORT OF A COLLABORATIVE STUDY AND COMPARISON OF ESTIMATES OF HUMAN PROLACTIN MADE IN VARIOUS LABORATORIES

1979 ◽  
Vol 80 (1) ◽  
pp. 157-168 ◽  
Author(s):  
ROSE E. GAINES DAS ◽  
P. MARY COTES
Keyword(s):  
Human Plasma ◽  
Collaborative Study ◽  
World Health ◽  
Expert Committee ◽  
International Reference ◽  
Two Samples ◽  
Human Prolactin ◽  
Reference Preparation ◽  
Prolactin Content ◽  
Made In

As authorized by the World Health Organization 29th Expert Committee on Biological Standardization, the preparation of human prolactin in ampoules coded 75/504 has been established as the International Reference Preparation (IRP) of human prolactin for immunoassay. From the results of a collaborative study, to which 15 laboratories in nine countries contributed, with the agreement of the participants, the content of each ampoule is defined as 0·650 International Units (i.u.; 650 mi.u.) immunoassay. The results of this collaborative study show that the IRP is adequately stable and suitable for use as a standard for the determination of prolactin in human plasma and serum. Estimates of the prolactin content of human plasma and serum made in the various laboratories have been compared and show good agreement in ranking order, but only fair agreement in the numerical value of the estimates. Numerical agreement is poor between estimates of the human prolactin content of two samples identical except for coding; this shows the difficulty in achieving continuity of estimates when any laboratory calibrates a replacement standard.

The Second International Reference Preparation of Thyroid-Stimulating Hormone, Human, for Immunoassay: calibration by bioassay and immunoassay in an international collaborative study

1985 ◽  
Vol 104 (3) ◽  
pp. 367-379 ◽  
Author(s):  
R. E. Gaines Das ◽  
A. F. Bristow
Keyword(s):  
Collaborative Study ◽  
Thyroid Stimulating Hormone ◽  
World Health ◽  
Expert Committee ◽  
International Reference ◽  
Reference Preparation ◽  
International Collaborative ◽  
Health Organization ◽  
International Collaborative Study ◽  
Second International

ABSTRACT Four batches of ampouled materials in ampoules coded 80/558, 81/502, 81/565 and 81/615 were evaluated by 22 laboratories in nine countries in an international collaborative study for their suitability to serve as a replacement for the First International Reference Preparation (IRP) of TSH, Human, for Immunoassay. The ampouled preparations were calibrated by immunoassay and bioassay. The preparation coded 80/558 had satisfactory stability and contained acceptably low levels of contamination with FSH and LH. Estimates of the immunoreactive TSH content of a set of specimens of serum in terms of 80/558 showed agreement in ranking order and no increase in variability compared with estimates made by assay against the First IRP. On the basis of these results, with the agreement of the participants in the study, and with the authorization of the Expert Committee on Biological Standardization of the World Health Organization, the preparation coded 80/558 was established in 1983 as the Second International Reference Preparation of TSH, Human, for Immunoassay, with a defined potency of 37 mi.u./ampoule. Preparations coded 81/502, 81/565 and 81/615 were found suitable to serve as working standards. J. Endocr. (1985) 104, 367–379

International Collaborative Study for the Establishment of the Second International Reference Preparation of Plasmin

1983 ◽  
Vol 50 (03) ◽  
pp. 645-649 ◽  
Author(s):  
P J Gaffney ◽  
M V Mussett
Keyword(s):  
Collaborative Study ◽  
World Health ◽  
Expert Committee ◽  
Glycerol Solution ◽  
International Reference ◽  
Freeze Dried ◽  
Reference Preparation ◽  
International Collaborative ◽  
International Collaborative Study ◽  
Second International

SummaryAn international collaborative study involving seven laboratories was undertaken to assess the suitability of a freeze- dried preparation of human plasmin to replace the current International Reference Preparation (IRP) for plasmin. Chromogenic and fibrinolytic assays were used by all participating laboratories to assess the potencies of the Proposed International Reference Preparation (PIRP) and two other freeze-dried plasmins, one of human and one of porcine originThe data suggest that the PIRP is a more suitable standard for plasmin than the IRP in that the former binds to fibrin whereas only 50% of the latter binds. The PIRP compared well to other plasmin preparations and the potency assays were independent of the assay procedure and substrate used. Degradation studies indicated that the PIRP was far more stable than the glycerol solution of the IRP, surviving for 12 months at 37° C with no significant loss in either amidolytic or fibrinolytic activity. The International Committee for Thrombosis and Haemostasis (Bergamo, 1982) has recommended the use of this material as a standard and it has been established by the Expert Committee on Biological Standardization of the World Health Organization as the second International Reference Preparation for Plasmin with a defined potency of 10 International Units of Plasmin per ampoule.

International Standards for human Prolactin: calibration by international collaborative study

1989 ◽  
Vol 121 (1) ◽  
pp. 157-NP ◽  
Author(s):  
D. Schulster ◽  
R. E. Gaines Das ◽  
S. L. Jeffcoate
Keyword(s):  
Collaborative Study ◽  
Physicochemical Analysis ◽  
International Standards ◽  
World Health ◽  
Expert Committee ◽  
International Standard ◽  
Human Prolactin ◽  
Cell Assays ◽  
Reference Preparation ◽  
Health Organization

ABSTRACT Three ampouled preparations of purified human prolactin were assessed by 20 laboratories in eight countries for their suitability to serve as International Standards for the estimation of human prolactin in serum. Bioassays (pigeon crop sac assays and NB2 cell assays) were carried out in two laboratories, radioreceptor assays by one laboratory and radioimmunoassays by 17 laboratories. By physicochemical analysis the preparations appeared similar. Each preparation contained small amounts of contaminants and/or prolactin variants. No major differences among the three preparations were detected by immunoassay although, in one radioreceptor assay system, one of the preparations was found to differ from the other two. On the basis of all the available information, the Expert Committee on Biological Standardization of the World Health Organization (ECBS) in 1986 established the preparation in ampoules coded 83/562 as the Second International Standard for Prolactin and in October 1988 established the preparation in ampoules coded 84/500 as the Third International Standard for Prolactin. A value of 0·053 IU (53 mIU) prolactin activity/ampoule was assigned to both the Second and Third IS on the basis that this unitage would, insofar as possible, maintain continuity of the IU defined by the First International Reference Preparation of Prolactin, human, for Immunoassay (coded 75/504). Journal of Endocrinology (1989) 121, 157–166

Calibration of Reference Thromboplastins and Standardisation of the Prothrombin Time Ratio

1983 ◽  
Vol 49 (03) ◽  
pp. 238-244 ◽  
Author(s):  
T B L Kirkwood
Keyword(s):  
Prothrombin Time ◽  
Oral Anticoagulants ◽  
Collaborative Study ◽  
World Health ◽  
Expert Committee ◽  
Calibration Model ◽  
Biological Standardization ◽  
Reference Preparation ◽  
Health Organization ◽  
Practical Implications

SummaryThromboplastins vary in their sensitivity to the haemostatic defect induced by oral anticoagulants. To provide a means of standardising prothrombin time tests, the World Health Organization adopted in 1977 a scheme for calibrating thromboplastins in terms of an International Reference Preparation. Unfortunately, the model on which this scheme was based does not always hold. A revised calibration model has therefore been developed and this has been tested in a recent collaborative study. The revised model, which retains fundamentally the same principle for standardising prothrombin time tests, has proved suitable for calibrating thromboplastins of different species and types and, moreover, has certain statistical advantages over its predecessor. In September 1982, the WHO Expert Committee on Biological Standardization adopted the revised model. This paper explains the nature and rationale of this change and considers its practical implications.

Establishment of the second international standards for porcine and human calcitonins: report of the international collaborative study

1993 ◽  
Vol 128 (5) ◽  
pp. 443-450 ◽  
Author(s):  
Joan M Zanelli ◽  
Rose E Gaines-Das ◽  
P Corran
Keyword(s):  
World Health Organization ◽  
Collaborative Study ◽  
International Standards ◽  
World Health ◽  
International Reference ◽  
International Standard ◽  
Reference Preparation ◽  
Health Organization ◽  
International Collaborative Study

The biological potency of calcitonins in clinical use in long-term treatment of Paget's disease of bone and, increasingly, in osteoporosis is usually expressed in international units defined by the relevant World Health Organization international reference preparation. The international reference preparations for porcine and human calcitonins were ampouled in 1970 and stocks are now exhausted. Replacement standards were ampouled in 1989 and have been evaluated and calibrated by an international collaborative study comprising 16 laboratories in 12 countries. Evaluations included high-performance liquid chromatography and in vitro bioassay; calibration of each new ampouled preparation in terms of its international reference preparation was by in vivo rat hypocalcaemia bioassay. On the basis of the results of the study and with the agreement of the participants, replacement standards were established by the Expert Committee on Biological Standardization of the World Health Organization in 1991: the international standard for porcine calcitonin (ampoule code 89/540), with an assigned potency of 0.8 international units per ampoule, and the international standard for human calcitonin, with an assigned potency of 17.5 international units per ampoule. Both international standards appeared to be sufficiently stable to serve as the international standards for in vivo biological assays. Comparison of the two species of calcitonin in the same hypocalcaemia assay showed that they were approximately equipotent when the doses were given intravenously but that the human peptide was four- to sixfold more potent than porcine calcitonin when doses were given subcutaneously, emphasizing the need to compare "like with like".

The International Reference Preparation of Tetracosactide for Bioassay: characterization and estimation of its (1–24)corticotrophin-tetracosapeptide content by physicochemical and biological methods

1984 ◽  
Vol 100 (1) ◽  
pp. 51-60 ◽  
Author(s):  
P. L. Storring ◽  
G. Witthaus ◽  
R. E. Gaines Das ◽  
W. Stamm
Keyword(s):  
High Performance ◽  
Storage Conditions ◽  
World Health ◽  
Expert Committee ◽  
Adrenocortical Cell ◽  
International Reference ◽  
Cell Assay ◽  
Reference Preparation

ABSTRACT The preparation and nature of the International Reference Preparation of Tetracosactide for Bioassay (IRP; in ampoules coded 80/590) are described. The IRP was studied by six laboratories in five countries using in-vivo and in-vitro bioassays and various physicochemical methods. The bulk (1–24)corticotrophin-tetracosapeptide (batch 000179) from which the IRP was prepared contained 10·4% (w/w) acetic acid and 8·3% (w/w) water; its (1–24)corticotrophin-tetracosapeptide content was estimated to be 71·7% (w/w) by amino acid analysis, 74·2% (w/w) by high performance liquid chromatography (HPLC) and 77·5% (w/w) by spectrophotometry. (1–24)Corticotrophin-tetracosapeptide accounted for more than 90% (w/w) of the total peptide in the IRP as judged by HPLC, thin-layer chromatography, carboxymethyl-cellulose chromatography, isoelectric focusing (IEF) and electrophoresis. The homogeneity of the peptide in the IRP was similar by all methods to that in batch 000179 from which it was prepared. The (1–24)corticotrophin-tetracosapeptide content of the IRP (with 95% confidence limits), in terms of batch 000179, was found to be 491 μg/ampoule by HPLC and spectrophotometry, 473 (433–513) μg/ ampoule by IEF and 505 (473–539) μg/ampoule by the in-vitro rat adrenocortical cell assay. A comparison in the same bioassay system of the IRP with a laboratory house standard of (1–24)corticotrophin-tetracosapeptide, which originated from a different manufacturer, gave similar results. Accelerated thermal degradation studies of the IRP by adrenocortical cell assay, HPLC and IEF suggested that more than 99·9% of its original content of (1–24)corticotrophin-tetracosapeptide would remain after 10 years under normal storage conditions of − 20 °C in the dark. Bioassay estimates of samples of the IRP which had undergone significant degradation were higher than estimates by HPLC, indicating that molecular species other than (1–24)corticotrophin-tetracosapeptide contributed to their corticotrophic activity. The corticotrophic activity of the IRP was demonstrated by cytochemical bioassay and by in-vivo bioassay as well as by the adrenocortical cell assay. After consideration of these data, the Expert Committee on Biological Standardization of the World Health Organization established the ampouled preparation, coded 80/590, as the International Reference Preparation of Tetracosactide for Bioassay and assigned to it a potency of 490 i.u./ampoule; thus the i.u. is represented by 1 μg (1–24)corticotrophin-tetracosapeptide. J. Endocr. (1984) 100, 51–60

The International Reference Preparation of Calcitonin, Human, for Bioassay: Assessment of material and definition of the International Unit

1980 ◽  
Vol 93 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Rose E. Gaines Das ◽  
Joan M. Zanelli
Keyword(s):  
Collaborative Study ◽  
World Health ◽  
Human Calcitonin ◽  
International Unit ◽  
International Reference ◽  
Reference Preparation ◽  
Definition Of ◽  
Health Organization ◽  
International Collaborative Study

Abstract. An international reference material is required for bioassays of preparations of synthetic human calcitonin for administration to man and for use in immunoassays. A preparation of synthetic human calcitonin in ampoules coded 70/234 (previously widely used as the MRC Research Standard) has been examined in an international collaborative study involving 7 laboratories in 6 countries. The results of 34 in vivo bioassays with two other preparations of synthetic human calcitonin showed that this preparation was suitable to serve as a standard. With the agreement of the participants in the collaborative study, the batch of ampoules, code 70/234, was established in 1978 by the World Health Organization as the International Reference Preparation of Calcitonin, Human, for Bioassay. The International Unit of human calcitonin was defined as the activity contained in one ampoule of this preparation, thus maintaining continuity of the unit of the research standard.

The International Reference Preparation of Gonadorelin for Bioassay: a comparison with different preparations of synthetic luteinizing hormone releasing hormone using physicochemical methods of analysis, different bioassays and immunoassay

1982 ◽  
Vol 95 (1) ◽  
pp. 95-103 ◽  
Author(s):  
P. L. Storring ◽  
P. H. Corran ◽  
Rose E. Gaines Das ◽  
D. H. Calam
Keyword(s):  
Luteinizing Hormone ◽  
Collaborative Study ◽  
World Health ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
International Reference ◽  
Methods Of Analysis ◽  
Reference Preparation ◽  
Physicochemical Methods ◽  
Lh Rh

The preparation and nature of the International Reference Preparation of Gonadorelin for Bioassay (IRP; coded 77/596) are described. The IRP was studied by four laboratories in four countries and compared, using physicochemical methods of analysis, various bioassay procedures and immunoassay, with preparations of synthetic luteinizing hormone releasing hormone (LH-RH) produced by different manufacturers. Analyses by thin-layer chromatography and by reverse-phase high-performance liquid chromatography (HPLC) indicated some heterogeneity of the peptide present in most of these preparations of synthetic LH-RH, including that of the IRP; the latter preparation appeared to be 88·3% (w/w) pure, judged by HPLC. The data from the collaborative study suggested that each ampoule of the IRP contains approximately 31 nmol LH-RH. The IRP appeared to be suitable to serve as an international reference preparation for bioassay since its behaviour was similar in different bioassays, so far as this could be examined, to that of the other preparations of LH-RH with which it was compared. Furthermore, the biological activities of different preparations of LH-RH, assessed in terms of the IRP, appeared to correlate with their degrees of purity assessed by physicochemical methods, suggesting that the peptides other than LH-RH present in the IRP did not contribute significantly to the biological activity of the preparation in these assay procedures. The limited data available suggested that the IRP might also be suitable as a reference preparation for immunoassay. The ampouled preparation, coded 77/596, was therefore established by the World Health Organization as the International Reference Preparation of Gonadorelin for Bioassay and assigned a unitage of 31 i.u./ampoule on the basis that the i.u. is represented by 1 nmole of LH-RH.

An international collaborative study on standardization of apolipoproteins A-I and B. Part I. Evaluation of a lyophilized candidate reference and calibration material.

1987 ◽  
Vol 33 (12) ◽  
pp. 2240-2249 ◽  
Author(s):  
S J Smith ◽  
G R Cooper ◽  
L O Henderson ◽  
W H Hannon
Keyword(s):  
Reference Material ◽  
Collaborative Study ◽  
Study Data ◽  
World Health ◽  
Expert Committee ◽  
Response Curves ◽  
Apo B ◽  
Reference Preparation ◽  
International Collaborative ◽  
International Collaborative Study

Abstract We evaluated a lyophilized serum preparation for use as a candidate Reference Material for apolipoproteins (apo) A-I and B. An international collaborative study was conducted with 28 participating laboratories, selected on the basis of participation and demonstrated expertise in a 1983 survey of apolipoproteins A-I and B. The analytical suitability of the material was established by confirming linearity of its dose-response curves over a desired concentration range and demonstrating that its response curves paralleled those for fresh sera. Differences in dilution-adjusted mass units ascribable to the five analytical methods used by the various laboratories constituted only 1% of the total variation for apo A-I, but 32% for apo B. The dominant source of error, however, for both apo A-I and B was the variability among laboratories, rather than variability among methods and antisera. The assigned consensus mass-concentration units based on study data are 1.124 g/L for apo A-I, 0.589 g/L for apo B. For these estimates the coefficients of variation were 13% and 27%, respectively. These findings on the proposed Reference Material meet the requirements suggested by the World Health Organization's Expert Committee on Biological Standards for a candidate WHO Reference Preparation.

A Collaborative Calibration Study of Reference Materials for Thromboplastins

1983 ◽  
Vol 50 (03) ◽  
pp. 712-717 ◽  
Author(s):  
J Hermans ◽  
A M H P van den Besselaar ◽  
E A Loeliger ◽  
E A van der Velde
Keyword(s):  
Reference Materials ◽  
Collaborative Study ◽  
World Health Organisation ◽  
World Health ◽  
Tissue Type ◽  
Human Brain Tissue ◽  
International Reference ◽  
Reference Preparation ◽  
Calibration Study ◽  
Bovine Type

SummaryIn a collaborative study of ten laboratories performed mainly within the framework of the BCR (the European Community Bureau of Reference), five thromboplastins were calibrated against the WHO (World Health Organisation) primary international reference preparation 67/40. Of these five thromboplastins, three were BCR reference materials (BCT/099, OBT/79 and RBT/79) and two were WHO secondary international reference preparations (68/434 and 70/178). Human brain tissue type is represented by 67/40 and BCT/099; bovine type by 68/434 and OBT/79, and rabbit type by 70/178 and RBT/79.The calibration relations are expressed in terms of a linear relationship between the logarithms of the prothrombin times, measured in seconds.

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