Abstract 11295: Sonoreperfusion Therapy for Microvascular Obstruction Using Microbubbles and Low Dose tPa

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Sebastiaan T Roos ◽  
Francois T Yu ◽  
Xucai Chen ◽  
Otto Kamp ◽  
Albert C van Rossum ◽  
...  
Keyword(s):  
Whole Blood ◽  
Low Dose ◽  
Microvascular Obstruction ◽  
Microvascular Perfusion ◽  
Additive Effect ◽  
Pulse Interval ◽  
Mechanical Index ◽  
Time Curve ◽  
Upstream Pressure

Background: Despite successful epicardial recanalization in acute myocardial infarction, adequate microvascular perfusion often fails due to embolization of thrombotic debris causing microvascular obstruction (MVO). We previously reported that long tone burst high mechanical index ultrasound (US) + microbubbles (MB) restored microvascular perfusion (sonoreperfusion, SRP) in an in vitro flow model using PBS perfusate. We sought to demonstrate SRP efficacy in whole blood perfusate with and without low dose tPa. Methods: The model comprised a 4 mm diameter phantom vessel with a 40 μm pore mesh to simulate a microvascular cross section and upstream pressure reflecting thrombus burden. Bovine whole blood and 2x10 6 /ml lipid MB (~3 μm) infused at 0.75 ml/min simulated microvascular flow. Bovine blood microthrombi were injected onto the mesh until upstream pressure was 30 mmHg. US was delivered for 20 min (1 MHz, 1.5 MPa peak negative pressure, 3 sec pulse interval, 1000-5000 cycles) with and without low dose tPa (2.5 μg/ml) during measurement of upstream pressure to assess SRP efficacy (n = 3-7). Lytic rate (rate of pressure drop in the first 4 min) and lytic index (1/area under pressure-time curve) quantified SRP efficacy. Results: In whole blood, lytic rate was 2.6 ± 1.5 mmHg/min at 1000 cycles US+MB increasing to 7.3 ± 3.2 mmHg/min at 5000 cycles US+MB (p<0.01) without tPa. The lytic index was similar for tPa only (2.0 ± 0.5) x 10 -3 mmHg -1 .min -1 and 5000 cycles US + MB without tPa (2.3 ± 0.5) x 10 -3 mmHg -1 .min -1 (p=0.5) but increased to (3.6 ± 0.8) x 10 -3 mmHg -1 .min -1 (p<0.01) for 5000 cycles US+MB+tPa, indicating an additive effect of tPa with US + MB therapy (Fig 1). Conclusions: In whole blood, US + MB therapy restored microvascular perfusion. Similarly to our previous findings with PBS perfusate, SRP efficacy varied with cycle length in the presence of MB. The addition of tPa increased SRP efficacy in blood, suggesting a potential additive effect of low dose tPa and US + MB therapy in vivo .

Thrombolytic Properties of Pro-Urokinase, Plasminogen Proactivator (PPA)

1987 ◽  
Author(s):  
Y Iga ◽  
K Tanaka ◽  
M Tsukada ◽  
S Kameyama ◽  
S Morichi ◽  
...  
Keyword(s):  
Whole Blood ◽  
Femoral Vein ◽  
Blood Perfusion ◽  
Human Kidney ◽  
Lag Phase ◽  
Perfusion Medium ◽  
Time Curve ◽  
Vein Thrombosis

Thrombolytic properties of highly purified plasminogen proactivator (PPA) isolated from culture medium of human kidney cells were compared with those of human urinary urokinase(u-UK). When 125-I-PPA or u-UK was added to whole blood perfusion medium containing preformed thrombi made from whole blood by Chandler loop method, the rates of uptake by the thrombi of PPA and u-UK for 4 hrs were only 2.5% and 2.7% respectively. Using the same thrombi and perfusion medium, an in vitro thrombolytic effect of PPA was examined over a 4 hr period. In early perfusion time, a lag phase was observed in the lysis-time curve of PPA, but not of u-UK. After the lag phase, the lysis by PPA increased linearly without early reaching a low level plateau that was characteristic of the lysis by u-UK. At 4hr, the PPA percent lysis was higher than the u-UK figure. Half lives in rabbit of 125-I-labelled PPA and u-UK iv doses were 5.1±0.2 min and 7.3±0.2 min respectively.The thrombolytic ability of PPA in vivo was evaluated in rabbit pulmonary embolism induced by iv 125-I-fibrin suspension as well as cynomolgus monkey femoral vein thrombosis produced by formation of 125-I-fibrinogen labelled clot in an isolated segment of the vein. In both models, PPA was as effective in thrombolysis as u-UK. However conversion to active UK form, consumptions of plsminogen and PI, fibrinogenolysis and prolongation of APTT in plasma were minor in the PPA group, but not in the u-UK group. It is thus suggested that PPA may cause a local activation limited on the fibrin to lead to a lysis of the thrombi without incurring systemic fibrinolysis

scholarly journals Spectroscopic Studies of in Vitro Exposure to Low-Dose Gamma Rays from 137Cs Radioactivity on Some Human Blood Components (Plasma and Red Blood Cells)

2021 ◽  
Author(s):  
Benjamaporn Supawat ◽  
Watcharit Vorasiripreecha ◽  
Sakornniya Wattanapongpitak ◽  
Suchart Kothan ◽  
Montree Tungjai
Keyword(s):  
Red Blood Cells ◽  
Gamma Rays ◽  
Human Blood ◽  
Whole Blood ◽  
Blood Cells ◽  
Low Dose ◽  
Radioactive Cesium ◽  
Blood Components ◽  
Blood Samples

Abstract This current study was to determine the effects of in vitro exposure to radioactive cesium-137 on some human blood components (Plasma and red blood cells). Blood samples were given a radiation dose of 0.02, 0.05, 0.1, 0.2, and 0.3 mGy of gamma rays using a 137Cs radioactive standard source. The blood samples that were exposed to 0 mGy served as sham-controls. The spectrofluoroscopic technique was used to determine the autofluorescence spectrum of protein in plasma or red blood cells by using excitation wavelength and range of emission wavelengths at 280 nm and 300-550 nm, respectively. The spectrophotometric technique was used to determine the release of hemoglobin from the red blood cells to the supernatant. This data indicated no change in the ratio of fluorescence emission intensity at 340 nm of wavelength of protein extract from irradiated whole blood or red blood cells compared to the corresponding non-irradiated control. The results did not change in the absorption intensity at 415 nm of wavelength of hemoglobin leakage from in vitro irradiated red blood cells when compared to the corresponding non-irradiated red blood cells. These current results suggested that there were no harmful effects of the low-dose gamma rays from radioactive 137Cs on some blood components when human whole blood was exposed to gamma rays in an in vitro condition.

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

1980 ◽  
Vol 44 (01) ◽  
pp. 006-008 ◽  
Author(s):  
D Bergqvist ◽  
K-E Arfors
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
In Vitro Test ◽  
Pharmacological Agents ◽  
Vitro Test ◽  
Releasing Effect ◽  
Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

Monitoring Anticoagulant Therapy by Activated Partial Thromboplastin Time: Hirudin Assessment

1994 ◽  
Vol 72 (05) ◽  
pp. 685-692 ◽  
Author(s):  
Michael T Nurmohamed ◽  
René J Berckmans ◽  
Willy M Morriën-Salomons ◽  
Fenny Berends ◽  
Daan W Hommes ◽  
...  
Keyword(s):  
Whole Blood ◽  
Partial Thromboplastin Time ◽  
Ex Vivo ◽  
Fold Increase ◽  
Heparin Therapy ◽  
Activated Partial Thromboplastin Time ◽  
Recombinant Hirudin ◽  
Interindividual Differences ◽  
The Relationship

SummaryBackground. Recombinant hirudin (RH) is a new anticoagulant for prophylaxis and treatment of venous and arterial thrombosis. To which extent the activated partial thromboplastin time (APTT) is suitable for monitoring of RH has not been properly evaluated. Recently, a capillary whole blood device was developed for bed-side monitoring of the APTT and it was demonstrated that this device was suitable to monitor heparin therapy. However, monitoring of RH was not evaluated.Study Objectives. To evaluate in vitro and ex vivo the responsiveness and reproducibility for hirudin monitoring of the whole blood monitor and of plasma APTT assays, which were performed with several reagents and two conventional coagulometers.Results. Large interindividual differences in hirudin responsiveness were noted in both the in vitro and the ex vivo experiments. The relationship between the APTT, expressed as clotting time or ratio of initial and prolonged APTT, and the hirudin concentration was nonlinear. A 1.5-fold increase of the clotting times was obtained at 150-200 ng/ml plasma. However, only a 2-fold increase was obtained at hirudin levels varying from 300 ng to more than 750 ng RH/ml plasma regardless of the assays. The relationship linearized upon logarithmic conversion of the ratio and the hirudin concentration. Disregarding the interindividual differences, and presuming full linearity of the relationship, all combinations were equally responsive to hirudin.Conclusions. All assays were equally responsive to hirudin. Levels up to 300 ng/ml plasma can be reliably estimated with each assay. The manual device may be preferable in situations where rapid availability of test results is necessary.

Studies on Thrombolysis with Streptokinase

1971 ◽  
Vol 25 (02) ◽  
pp. 354-378 ◽  
Author(s):  
R Gottlob ◽  
L Stockinger ◽  
U Pötting ◽  
G Schattenmann
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Whole Blood ◽  
Jugular Vein ◽  
Thin Sections ◽  
The Third ◽  
Morphological Findings ◽  
Blood Clots ◽  
Arteries And Veins

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

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.

A Simple and Rapid Method to Determine GPIIb/IIIa-Receptor Inhibitor Activity in Whole Blood

1999 ◽  
Vol 19 (03) ◽  
pp. 134-138
Author(s):  
Gitta Kühnel ◽  
A. C. Matzdorff
Keyword(s):  
Flow Cytometry ◽  
Platelet Count ◽  
Blood Sample ◽  
Platelet Activation ◽  
Whole Blood ◽  
Receptor Occupancy ◽  
Aggregate Formation ◽  
Inhibitor Activity ◽  
Receptor Inhibitor

SummaryWe studied the effect of GPIIb/IIIa-inhibitors on platelet activation with flow cytometry in vitro. Citrated whole blood was incubated with increasing concentrations of three different GPIIb/IIIa-inhibitors (c7E3, DMP728, XJ757), then thrombin or ADP were added and after 1 min the sample was fixed. Samples without c7E3 but with 0.1 U/ml thrombin had a decrease in platelet count. Samples with increasing concentrations of c7E3 had a lesser or no decrease in platelet count. The two other inhibitors (DMP 725, XJ757) gave similar results. GPIIb/IIIa-inhibitors prevent aggregate formation and more single platelets remain in the blood sample. The agonist-induced decrease in platelet count correlates closely with the concentration of the GPIIb/IIIa inhibitor and receptor occupancy. This correlation may be used as a simple measure for inhibitor activity in whole blood.

Early Platelet-Collagen Interactions in Whole Blood and Their Modifications by Aspirin and Dipyridamole Evaluated by a New Method (Basic Wave)

1985 ◽  
Vol 54 (04) ◽  
pp. 799-803 ◽  
Author(s):  
José Luís Pérez-Requejo ◽  
Justo Aznar ◽  
M Teresa Santos ◽  
Juana Vallés
Keyword(s):  
Whole Blood ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
White Blood Cells ◽  
Reversible Aggregation ◽  
Inhibitory Compounds ◽  
Rapid Generation ◽  
Stimulation Of ◽  
Collagen Stimulation

SummaryIt is shown that the supernatant of unstirred whole blood at 37° C, stimulated by 1 μg/ml of collagen for 10 sec, produces a rapid generation of pro and antiaggregatory compounds with a final proaggregatory activity which can be detected for more than 60 min on a platelet rich plasma (PRP) by turbidometric aggregometry. A reversible aggregation wave that we have called BASIC wave (for Blood Aggregation Stimulatory and Inhibitory Compounds) is recorded. The collagen stimulation of unstirred PRP produces a similar but smaller BASIC wave. BASIC’s intensity increases if erythrocytes are added to PRP but decreases if white blood cells are added instead. Aspirin abolishes “ex vivo” the ability of whole blood and PRP to generate BASIC waves and dipyridamole “in vitro” significantly reduces BASIC’s intensity in whole blood in every tested sample, but shows little effect in PRP.

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