How to best monitor bivalirudin anticoagulant effect for ECMO and VAD—Comparison of four assay methods

2021 ◽  
Author(s):  
Jun Teruya ◽  
Karen Bruzdoski ◽  
Lisa Hensch ◽  
Shiu‐Ki Rocky Hui ◽  
Vadim Kostousov
Keyword(s):  
Anticoagulant Effect ◽  
Assay Methods

Lack of Agreement of Chromogenic and Glotting Assays for Factor X and Protein C in Warfarinised Plasma

1991 ◽  
Vol 65 (04) ◽  
pp. 360-363 ◽  
Author(s):  
P Han ◽  
K P Fung ◽  
U Rahdakrishnan
Keyword(s):  
Serine Proteases ◽  
Protein C ◽  
Warfarin Therapy ◽  
Intraclass Correlation ◽  
Chromogenic Substrate ◽  
Factor X ◽  
Laboratory Automation ◽  
Quantitative Results ◽  
Assay Methods

SummaryCoagulation serine proteases can be measured with either a chromogenic substrate assay or a clotting assay using deficient plasmas. It is a concern whether both assays give similar quantitative results, in particular in plasma obtained fiom patients on long term warfarin therapy. If these two assay methods were interchangeable, then the chromogenic substrate assay has the advantages of precision as well as laboratory automation. We used the intraclass correlation coefficient (r1) to assess the agreement between the two methods in measuring factor X and protein C levels in warfarinised plasma. The results indicate that the extent and pattern of agreement of the two methods for the measurement of the two variables in warfarinised plasma are poor, despite high Pearson product moment coefficients of correlation.

Assay Methods and Standard Preparations for Plasmin, Plasminogen and Urokinase in Purified Systems, 1967-1968

1969 ◽  
Vol 21 (02) ◽  
pp. 259-272 ◽  
Author(s):  
A. J Johnson ◽  
D. L Kline ◽  
Norma Alkjaersig
Keyword(s):  
Heart Institute ◽  
Thrombolytic Agents ◽  
National Heart ◽  
Assay Methods

SummaryTo facilitate communication between investigators, the Committee on Thrombolytic Agents of the National Heart Institute suggests standardized reagents and assay methods for the measurement of standard preparations of plasmin, plasminogen, and urokinase with use of casein, fibrin and synthetic esters as substrates.

“In vitro” Neutralization with Oxalate Ion of the Anticoagulant Effect of Heparin

1961 ◽  
Vol 05 (02) ◽  
pp. 314-318 ◽  
Author(s):  
W. O Cruz ◽  
L Meis ◽  
C. P Dietrich
Keyword(s):  
Calcium Oxalate ◽  
Aluminium Hydroxide ◽  
Barium Sulfate ◽  
Anticoagulant Effect ◽  
Normal Plasma ◽  
Oxalate Ion

SummaryHeparinized blood or plasma coagulates if, after addition of oxalate, recalcification follows. Of the decalcifying agents only oxalate ion has been suitable for demonstrating this phenomenon. Oxalate seem to accomplish two different roles connected with this effect: a fundamental one, i. e., to sensitize a heparinlipoprotein complex to the action of an anti-heparin factor found in normal plasma or serum and a secondary one, related to its capacity to adsorb this antiheparin factor. The latter is removable by centrifugation. This anti-heparin oxalate factor, which is able to counteract the action of heparin after previous addition of oxalate, was found in sequestrened, Dowex 50 resin plasma or in serum, but is not active in citrated plasma. This factor was removed from plasma by adsorption with barium sulfate, aluminium hydroxide or calcium oxalate and was eluted from these adsorbants after incubation with saline.

A Collaborative Study Designed to Establish the 4th International Standard for Heparin

1984 ◽  
Vol 52 (02) ◽  
pp. 148-153 ◽  
Author(s):  
D P Thomas ◽  
A D Curtis ◽  
T W Barrowcliffe
Keyword(s):  
Collaborative Study ◽  
International Standard ◽  
Thrombin Inhibition ◽  
Freeze Dried ◽  
Assay Methods ◽  
The Mean ◽  
International Collaborative ◽  
International Collaborative Study

SummaryAn international collaborative study, in which 22 laboratories participated, was carried out to establish a replacement for the International Standard for Heparin. A total of 248 assays were analyzed, including APTT, thrombin inhibition and anti-Xa assays, as well as pharmacopoeial assays. Overall, there was less than 5% difference in the mean potency estimates of the candidate preparations, by all assay methods. The freeze-dried preparation 82/502 demonstrated the closest parallelism by bioassay to the existing standard and was established by WHO as the 4th International Standard for Heparin, with an assigned unitage of 1780 i.u. per ampoule.

In Vitro Methods for the Assessment of L-Cysteine Conjugate Toxicity

1994 ◽  
Vol 22 (2) ◽  
pp. 72-80
Author(s):  
Lorraine D. Buckberry ◽  
Harriet J. Adcock ◽  
Jeremy Adler ◽  
Ian S. Blagbrough ◽  
Peter J. Gaskin ◽  
...  
Keyword(s):  
Mechanism Of Action ◽  
Mammalian Species ◽  
Mercapturic Acid ◽  
Assay Method ◽  
Cellular Toxicity ◽  
In Vitro Methods ◽  
Metabolic Route ◽  
Assay Methods ◽  
Chang Liver

L-Cysteine conjugates are normally metabolised via N-acetylation to produce a mercapturic acid. However, a recently identified metabolic route (C-S lysis) may lead to the generation of an unstable thiol which has been demonstrated to be responsible for toxicity in various mammalian species. Human Chang liver cells were challenged with a number of established L-cysteine conjugates. The cellular toxicity of these compounds was determined using a range of assay procedures, which provided differing information, depending on the assay method used. These observations were then investigated in order to establish which system would provide the most reliable indication of C-S lyase toxicity and whether any information on the mechanism of action could be obtained by these assay methods.

EXPRESS: Method dependent variation in TSH and FT4 reference intervals in pregnancy: a systematic review

2021 ◽  
pp. 000456322110269
Author(s):  
O E Okosieme ◽  
Medha Agrawal ◽  
Danyal Usman ◽  
Carol Evans
Keyword(s):  
Systematic Review ◽  
Reference Interval ◽  
First Trimester ◽  
Reference Intervals ◽  
Assay Method ◽  
Specific Reference ◽  
Upper Limits ◽  
Wide Range ◽  
Assay Methods ◽  
In Pregnancy

Background: Gestational TSH and FT4 reference intervals may differ according to assay method but the extent of variation is unclear and has not been systematically evaluated. We conducted a systematic review of published studies on TSH and FT4 reference intervals in pregnancy. Our aim was to quantify method-related differences in gestation reference intervals, across four commonly used assay methods, Abbott, Beckman, Roche, and Siemens. Methods: We searched the literature for relevant studies, published between January 2000 and December 2020, in healthy pregnant women without thyroid antibodies or disease. For each study, we extracted trimester-specific reference intervals (2.5–97.5 percentiles) for TSH and FT4 as well as the manufacturer provided reference interval for the corresponding non-pregnant population. Results: TSH reference intervals showed a wide range of study-to-study differences with upper limits ranging from 2.33 to 8.30 mU/L. FT4 lower limits ranged from 4.40–13.93 pmol/L, with consistently lower reference intervals observed with the Beckman method. Differences between non-pregnant and first trimester reference intervals were highly variable, and for most studies the TSH upper limit in the first trimester could not be predicted or extrapolated from non-pregnant values. Conclusions: Our study confirms significant intra and inter-method disparities in gestational thyroid hormone reference intervals. The relationship between pregnant and non-pregnant values is inconsistent and does not support the existing practice in some laboratories of extrapolating gestation references from non-pregnant values. Laboratories should invest in deriving method-specific gestation reference intervals for their population.

scholarly journals Factors to consider when interrogating 3D culture models with plate readers or automated microscopes

2021 ◽  
Author(s):  
Terry Riss ◽  
O. Joseph Trask
Keyword(s):  
Cell Culture ◽  
Three Dimensional ◽  
3D Culture ◽  
Fluorescent Imaging ◽  
Culture Models ◽  
Assay Methods ◽  
Diffusion Rates ◽  
Cell Culture Models ◽  
Dimensional Cell ◽  
Cells Cultured

AbstractAlong with the increased use of more physiologically relevant three-dimensional cell culture models comes the responsibility of researchers to validate new assay methods that measure events in structures that are physically larger and more complex compared to monolayers of cells. It should not be assumed that assays designed using monolayers of cells will work for cells cultured as larger three-dimensional masses. The size and barriers for penetration of molecules through the layers of cells result in a different microenvironment for the cells in the outer layer compared to the center of three-dimensional structures. Diffusion rates for nutrients and oxygen may limit metabolic activity which is often measured as a marker for cell viability. For assays that lyse cells, the penetration of reagents to achieve uniform cell lysis must be considered. For live cell fluorescent imaging assays, the diffusion of fluorescent probes and penetration of photons of light for probe excitation and fluorescent emission must be considered. This review will provide an overview of factors to consider when implementing assays to interrogate three dimensional cell culture models.

The Development and Evaluation of In Vitro Tests by the FRAME Alternatives Laboratory

1995 ◽  
Vol 23 (1) ◽  
pp. 75-90
Author(s):  
Richard H. Clothier ◽  
Karen A. Atkinson ◽  
Michael J. Garle ◽  
Rachel K. Ward ◽  
Angela Willshaw
Keyword(s):  
Research Programme ◽  
Neutral Red ◽  
In Vitro Cytotoxicity ◽  
In Vitro Tests ◽  
Dermal Toxicity ◽  
Mechanisms Of Toxicity ◽  
The Us ◽  
Detergent Association ◽  
Assay Methods

This review outlines the work which has been conducted in the FRAME Alternatives Laboratory during the first ten years of the FRAME Research Programme. A number of in vitro tests, including the kenacid blue, neutral red release and fluorescein leakage assay methods, have been evaluated and have subsequently been included in validation schemes organised by the US Soap and Detergent Association, the US Cosmetic, Toiletry and Fragrance Association, the European Commission and the European Cosmetic, Toiletry and Perfumery Association, as well as in the Scandinavian multicentre evaluation of in vitro cytotoxicity testing scheme. More recently, research has been undertaken in the areas of phototoxicity, immunotoxicity, dermal toxicity and intercellular communication, in addition to investigations into fundamental mechanisms of toxicity.

Comparison of radioimmunoassay and thin layer chromatographie assay methods for estimation of plasma prednisolone concentrations

1981 ◽  
Vol 6 (2) ◽  
pp. 137-142 ◽  
Author(s):  
S.M.H. Al-Habet ◽  
W.A.C. McAllister ◽  
J.V. Collins ◽  
H.J. Rogers
Keyword(s):  
Thin Layer ◽  
Assay Methods
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