scholarly journals On-Chip Titration of an Anticoagulant Argatroban and Determination of the Clotting Time within Whole Blood or Plasma Using a Plug-Based Microfluidic System

2006 ◽  
Vol 78 (14) ◽  
pp. 4839-4849 ◽  
Author(s):  
Helen Song ◽  
Hung-Wing Li ◽  
Matthew S. Munson ◽  
Thuong G. Van Ha ◽  
Rustem F. Ismagilov
Keyword(s):  
Whole Blood ◽  
Microfluidic System ◽  
Clotting Time ◽  
On Chip

An integrated microfluidic system for on-chip enrichment and quantification of circulating extracellular vesicles from whole blood

Lab on a Chip ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 3305-3315 ◽  
Author(s):  
Yi-Sin Chen ◽  
Yu-Dong Ma ◽  
Chihchen Chen ◽  
Shu-Chu Shiesh ◽  
Gwo-Bin Lee
Keyword(s):  
Extracellular Vesicles ◽  
Immunosorbent Assay ◽  
Whole Blood ◽  
Magnetic Beads ◽  
Extracellular Vesicle ◽  
Microfluidic System ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Whole Blood ◽  
On Chip ◽  
Chip Enrichment

An integrated microfluidic system was developed for extracellular vesicle (EV) enrichment and quantification by using anti-CD63-coated magnetic beads and an on-chip enzyme-linked immunosorbent assay in human whole blood.

A Machine for the Determination of the Whole Blood Clotting Time

1970 ◽  
Vol 23 (03) ◽  
pp. 627-632
Author(s):  
D. L Watt
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Heparin Therapy ◽  
Coagulation Disorders ◽  
Mechanical Device ◽  
Clotting Time ◽  
Normal Range ◽  
Glass Tubes ◽  
Blood Clotting Time

SummaryThe whole blood clotting time in glass tubes is widely used for the control of heparin therapy. In the investigation of coagulation disorders the whole blood clotting time is commonly done both in glass tubes and in tubes with non-wettable surfaces.This presentation concerns the development of a portable mechanical device, the Coagulation Timer, to perform this test. The end point is measured automatically by a photo-electric mechanism. Only a few minutes are required to draw blood and place samples in the machine, which may then be left unattended.Data are presented to show that results obtained using glass tubes in the Coagulation Timer correlate well with those of a technician using a modification of the Lee White method. Further data are presented establishing the normal range for the whole blood clotting time using polystyrene tubes in the Coagulation Timer.

Electrochemical determination of whole blood clotting time by using nanodot arrays

2009 ◽  
Vol 11 (11) ◽  
pp. 2141-2144 ◽  
Author(s):  
Jae Hoon Lim ◽  
Sung-Yu Hong ◽  
Soo Jung Kang ◽  
Hyun-Ju Doh ◽  
Jaewoo Song ◽  
...  
Keyword(s):  
Whole Blood ◽  
Blood Clotting ◽  
Electrochemical Determination ◽  
Clotting Time ◽  
Nanodot Arrays ◽  
Blood Clotting Time

Thrombelastography for the monitoring of lipopolysaccharide induced activation of coagulation

2006 ◽  
Vol 95 (03) ◽  
pp. 557-561 ◽  
Author(s):  
Paula Zacharowski ◽  
Kai Zacharowski ◽  
Christoph Sucker ◽  
Matthias Hartmann
Keyword(s):  
Tissue Factor ◽  
Whole Blood ◽  
Factor Viia ◽  
Clot Formation ◽  
Protein Synthesis Inhibitor ◽  
Clotting Time ◽  
Synthesis Inhibitor ◽  
Blood Samples ◽  
Whole Blood Samples

SummaryDuring Gram-negative sepsis, lipopolysaccharide (LPS) activates toll-like receptor (TLR) 4 and induces complex responses of immune system and haemostasis. In the present study we investigated whether thrombelastography is suitable to monitor the LPS-induced activation of coagulation. Whole blood samples from healthy volunteers were incubated with LPS for various in-cubation periods (0–5 hrs), thereafter rotation thrombelastography was performed. Incubation of whole blood (≥ 3 h) with LPS markedly reduced clotting time; after 5 hrs the variable was reduced from 459 ± 39 sec to 80 ± 20 sec while the other thrombelastography variables (angle α, clot formation time, maximal clot formation) remained unaltered. EC50 of the LPSeffect on whole blood clotting time was 18 µg/ml.In isolated leu kocytes, diluted in platelet poor plasma, far lower LPS-concentrations were effective: 10 ng/ml LPS reduced clotting time from 439 ± 68 sec to 200± 56 sec. Experiments with the protein synthesis inhibitor cycloheximide and active site-inhibited factor VIIa revealed that LPS exerts its effects via the synthesis of tissue factor.Addition of tissue factor to whole blood samples revealed that a concentration of 100 fmol/l can be detected using thrombelastography. In whole blood samples the tissue factor concentration induced by LPS amounted up to 12 pmol/l. In summary, thrombelastography proved to bea sensitive and reliable tool for the determination of LPS-induced tissue factor mediated activation of haemostasis in whole blood samples.

Monitoring of r-Hirudin Anticoagulation during Cardiopulmonary Bypass – Assessment of the Whole Blood Ecarin Clotting Time

1997 ◽  
Vol 77 (05) ◽  
pp. 0920-0925 ◽  
Author(s):  
Bernd Pötzsch ◽  
Katharina Madlener ◽  
Christoph Seelig ◽  
Christian F Riess ◽  
Andreas Greinacher ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Whole Blood ◽  
Heart Surgery ◽  
Ex Vivo ◽  
Open Heart Surgery ◽  
Clotting Time ◽  
Blood Samples ◽  
Alternative Approach ◽  
Ecarin Clotting Time

SummaryThe use of recombinant ® hirudin as an anticoagulant in performing extracorporeal circulation systems including cardiopulmonary bypass (CPB) devices requires a specific and easy to handle monitoring system. The usefulness of the celite-induced activated clotting time (ACT) and the activated partial thromboplastin time (APTT) for r-hirudin monitoring has been tested on ex vivo blood samples obtained from eight patients treated with r-hirudin during open heart surgery. The very poor relationship between the prolongation of the ACT and APTT values and the concentration of r-hirudin as measured using a chromogenic factor Ila assay indicates that both assays are not suitable to monitor r-hirudin anticoagulation. As an alternative approach a whole blood clotting assay based on the prothrombin-activating snake venom ecarin has been tested. In vitro experiments using r-hirudin- spiked whole blood samples showed a linear relationship between the concentration of hirudin added and the prolongation of the clotting times up to a concentration of r-hirudin of 4.0 µg/ml. Interassay coefficients (CV) of variation between 2.1% and 5.4% demonstrate the accuracy of the ecarin clotting time (ECT) assay. Differences in the interindividual responsiveness to r-hirudin were analyzed on r-hirudin- spiked blood samples obtained from 50 healthy blood donors. CV- values between 1.8% and 6% measured at r-hirudin concentrations between 0.5 and 4 µg/ml indicate remarkably slight differences in r-hirudin responsiveness. ECT assay results of the ex vivo blood samples linearily correlate (r = 0.79) to the concentration of r-hirudin. Moreover, assay results were not influenced by treatment with aprotinin or heparin. These findings together with the short measuring time with less than 120 seconds warrant the whole blood ECT to be a suitable assay for monitoring of r-hirudin anticoagulation in cardiac surgery.

Determination of the International Sensitivity Index of a New Near-Patient Testing Device to Monitor Oral Anticoagulant Therapy

1997 ◽  
Vol 78 (02) ◽  
pp. 855-858 ◽  
Author(s):  
Armando Tripodi ◽  
Veena Chantarangkul ◽  
Marigrazia Clerici ◽  
Barbara Negri ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Linear Relationship ◽  
Whole Blood ◽  
Oral Anticoagulant ◽  
Oral Anticoagulant Therapy ◽  
Oral Anticoagulants ◽  
Calibration Model ◽  
Testing Device ◽  
Data Points ◽  
Near Patient Testing

SummaryA key issue for the reliable use of new devices for the laboratory control of oral anticoagulant therapy with the INR is their conformity to the calibration model. In the past, their adequacy has mostly been assessed empirically without reference to the calibration model and the use of International Reference Preparations (IRP) for thromboplastin. In this study we reviewed the requirements to be fulfilled and applied them to the calibration of a new near-patient testing device (TAS, Cardiovascular Diagnostics) which uses thromboplastin-containing test cards for determination of the INR. On each of 10 working days citrat- ed whole blood and plasma samples were obtained from 2 healthy subjects and 6 patients on oral anticoagulants. PT testing on whole blood and plasma was done with the TAS and parallel testing for plasma by the manual technique with the IRP CRM 149S. Conformity to the calibration model was judged satisfactory if the following requirements were met: (i) there was a linear relationship between paired log-PTs (TAS vs CRM 149S); (ii) the regression line drawn through patients data points, passed through those of normals; (iii) the precision of the calibration expressed as the CV of the slope was <3%. A good linear relationship was observed for calibration plots for plasma and whole blood (r = 0.98). Regression lines drawn through patients data points, passed through those of normals. The CVs of the slope were in both cases 2.2% and the ISIs were 0.965 and 1.000 for whole blood and plasma. In conclusion, our study shows that near-patient testing devices can be considered reliable tools to measure INR in patients on oral anticoagulants and provides guidelines for their evaluation.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

scholarly journals Design and Manufacturing of a Disposable, Cyclo-Olefin Copolymer, Microfluidic Device for a Biosensor †

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1178 ◽  
Author(s):  
Jorge Prada ◽  
Christina Cordes ◽  
Carsten Harms ◽  
Walter Lang
Keyword(s):  
Microfluidic Device ◽  
Heating Temperature ◽  
Low Cost ◽  
Reaction Chamber ◽  
Microfluidic System ◽  
Heating Process ◽  
Design And Manufacturing ◽  
On Chip ◽  
Working Parameters ◽  
Auto Fluorescence

This contribution outlines the design and manufacturing of a microfluidic device implemented as a biosensor for retrieval and detection of bacteria RNA. The device is fully made of Cyclo-Olefin Copolymer (COC), which features low auto-fluorescence, biocompatibility and manufacturability by hot-embossing. The RNA retrieval was carried on after bacteria heat-lysis by an on-chip micro-heater, whose function was characterized at different working parameters. Carbon resistive temperature sensors were tested, characterized and printed on the biochip sealing film to monitor the heating process. Off-chip and on-chip processed RNA were hybridized with capture probes on the reaction chamber surface and identification was achieved by detection of fluorescence tags. The application of the mentioned techniques and materials proved to allow the development of low-cost, disposable albeit multi-functional microfluidic system, performing heating, temperature sensing and chemical reaction processes in the same device. By proving its effectiveness, this device contributes a reference to show the integration potential of fully thermoplastic devices in biosensor systems.

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