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Biomedical subjects

M Kapadvanjwala

Publications and source records attributed to M Kapadvanjwala.

At least 19 recordsLinked to original sources
PubMed1996

Reduction of Platelet Thrombi and Emboli by L-Arginine during Cardiopulmonary Bypass in a Pig Model.

We wanted to test the hypothesis that NO generation by L-arginine (LA) infusion will be beneficial in increasing blood flow to all organs to counteract the process of global ischemia during cardiopulmonary bypass (CPB) and to reduce platelet emboli by platelet inhibition. The effect of LA infusion on NO formation, vasodilation, and reduction of thromboembolic burden in organs and tissues after CPB was quantified with In-111-labeled autologous platelets in two major groups: 180 minutes CPB (CPB) and 90 minutes CPB plus 90 minutes reperfusion (RP). Platelets labeled with In-111 tropolone (650-780 µCi) were administered 24 hours before CPB and LA infusion (bolus, 10 mg/kg and infusion at 2 mg/kg/min, 21 pigs for 180 minutes CPB) in 8 groups of 30 Yorkshire pigs (30-35 kg, 6 pigs; LA 2 mg/kg/min, 3 pigs; sham-thoracotomy control, 6 pigs; unoperated control, 6 pigs). Two groups of 9 pigs (control CPB, 6 pigs; LA 2 mg/kg/min, 3 pigs) underwent 90 minutes of CPB and 90 minutes of reperfusion. All pigs were heparinized (ACT > 400 seconds); CPB was instituted with a roller pump, an oxygenator (OX: Bentley Univox, 1.8 m2), and an arterial filter (AF: 0.25 m2, Bentley) at a blood flow of 2.5-3.5 l/min. Radioactive thrombi in OX and AF and emboli in viscera, brain, and connective tissues were imaged with a gamma camera and were finally measured with an ion chamber and a gamma counter. The percent of injected platelets (mean +/- SD) in the organs and tissues of all pigs was calculated. Cerebral emboli were mapped in 25 regions of both hemispheres of pig brain. Flow cytometry with antibodies to CD61 (GPIIIa) and CD62P (GMP-140:control) of porcine platelets was carried out with blood samples taken before, during, and after CPB. Coronary bypass with LA infusion decreased the amount of adherent thrombi in OX and AF (p < 0.07). The embolic burden in brain and lung also decreased. Regional cerebral mapping of In-111 platelets showed reduced emboli in almost all regions, including the medulla, hip pocampus, and posterior cerebral cortex in both LA-treated groups. Flow cytometry of blood samples demonstrated the shift of equilibria from single platelet to platelet-aggregate-microparticle during CPB and steady-state level after the first 5-10 minutes of initiation of CPB. The L-arginine infusion reduced thrombi and emboli during CPB in the pig model.

Journal Article↗
PubMed1996

Effect of Thoracotomy and Cardiopulmonary Bypass on Activated Platelet and Neutrophil Dynamics and Platelet Emboli in a Pig Model.

The effects of thoracotomy and components of extracorporeal circuits on dynamics of platelets and neutrophils were quantified with autologous In-111-labeled platelets (INPLT) and neutrophils (INN) during cardiopulmonary bypass (CPB) operations in Yorkshire pigs. Cardiopulmonary bypass was carried out with a hollow-fiber oxygenator and an arterial filter in 48 pigs (30-35 kg; 12 unoperated controls for platelets and neutrophils; 12 sham operated controls; 12 with 180 minutes of CPB with platelets and neutrophils; 12 with 90 minutes of CPB and 90 minutes of reperfusion at 2.5-3.5 one/min. Platelets and neutrophils were labeled with In-111 tropolone and were injected intravenously: platelets at 24 hours and neutrophils at 15 minutes before CPB. All pigs were systemically heparinized [activated coagulation time (ACT) > 400 seconds]; CPB was instituted with a roller pump, oxygenator (OX; Bentley Univox, 1.8 m2), and arterial filter (AF; 0.025 m2) for durations of 180 minutes and 90 minutes of bypass, followed by 90 minutes of reperfusion. The kinetics and pooling of platelets and neutrophils were monitored by a Geiger probe. The adherent thrombi and neutrophils in the OX, AF, viscera, and brain were imaged with a gamma camera and were measured with an ion chamber and a gamma counter. The percentile distribution of labeled platelets and neutrophils expressed as the mean +/- standard deviation of injected dose in eight groups was calculated and statistical analyses were performed (ANOVA and paired t-test). Sham operation alone increased platelet retention in the lung, heart, and brain significantly (p < 0.001) over that of unoperated pigs. Neutrophil margination to lung immediately after injection was high; CPB and reperfusion altered the distribution in blood, viscera, and connective tissues. During CPB, an equilibrium among single platelets, platelet thrombi, and emboli was reached in the blood, oxygenator, arterial filter, perfused organs, and tissues. After CPB, the pulmonary neutrophil retention increased significantly (p < 0.001). Reperfusion of 90 minutes following 90 minutes of CPB decreased the level of neutrophils and increased the level of platelets in the lung. Only a small amount of platelets and neutrophils was retained in the oxygenator and arterial filter. Neutrophil retention in the OX and AF was higher than that of platelets. The small amount of retained neutrophils in the heart, kidneys, and brain suggested that cytokines, rather than marginated neutrophils alone, may play a major role in inflammatory insult to these organs during and after CPB. OX thrombi increased with the time of CPB; AF thrombus in both groups was almost similar. During CPB, AF functioned minimally as a thrombus trap with a small percent of retained thrombi; reperfusion post-CPB did not change the amount. Thoracotomy alone has a significant effect on platelet and neutrophil kinetics, and on the subsequent effect of thrombus formation, embolization, and neutrophil margination in organs during the CPB procedure.

Journal Article↗
PubMed1994

Comparative thrombogenicity of pacemaker leads.

To evaluate the thrombogenicity of transvenous silicone and polyurethane pacemaker leads, 9 of 12 anesthetized Yorkshire pigs (27-32 kg) were implanted with silicone (n = 5) or polyurethane (n = 4) pacemaker leads via a femoral vein. The remaining three pigs served as controls. All 12 pigs were injected with autologous indium-111 labeled platelets (300-420 muCi) 24 hours before anesthesia induction. The pigs were monitored for 3 hours under a gamma camera. Radioactivity in blood and lead segments was measured with a gamma counter. Platelet deposits were denser on silicone leads (441.58 +/- 915.0 to 2.19 +/- 2.07) than on polyurethane leads (1.21 +/- 1.33 to 0.27 +/- 0.14) (P > 0.05). Denser platelet deposits were detected at the tip of all leads. Density of platelet deposits declined from tip to distal segments in silicone leads. The percentage of injected platelet radioactivity in the lungs of pigs with either silastic leads (12.9 +/- 2.3%) of polyurethane leads (10.1 +/- 2.2%) was higher than in the controls (4.6 +/- 0.5%) (P < 0.05). This difference indicates thrombus formation and embolization in the lungs early after lead implantation. Thrombogenicity of polyurethane leads may be lower than that of silicone leads.

Animals↗
PubMed1994

Kinetics of hybridization of mRNA of c-myc oncogene with 111In-labeled antisense oligodeoxynucleotide probes by high-pressure liquid chromatography.

Antisense oligodeoxynucleotides (ASON) were labeled with gamma-emitting 123I, 99mTc and 111In radionuclides. The hybridization kinetics of 111In-labeled ASON probes [phosphorothioate (S) and phosphodiester (O)] with intact leukemic cells (P388) and purified mRNA was studied by gel filtration technique. The 15-mer oligodeoxynucleotide (ON) sequence was synthesized, amino linked and coupled to diethylenetriaminepentaacetic acid (DTPA)-isothiocyanate, and aliquots were lyophilized to make a kit for convenient preparation. 111In radionuclide was chelated to DTPAASON derivatives and free 111In was separated by gel filtration. The probe was incubated with P388 cells and mRNA extract of P388 cells. Hybridization kinetics was studied by measuring the free and mRNA-bound probe separated by the HPLC technique. The distribution of radioactivity associated with proteins, DNA and mRNAs was directly measured with a gamma camera and further quantified with an ionization chamber. The kinetics of direct and indirect hybridization of 111In-labeled antisense probes with mRNA and intact cells was similar.

Animals↗
PubMed1994

Noninvasive imaging of c-myc oncogene messenger RNA with indium-111-antisense probes in a mammary tumor-bearing mouse model.

UNLABELLED: The c-myc oncogene is amplified in leukemia and solid tumors, thus making the c-myc messenger RNA (mRNA) a suitable target for following the progression of malignancy by noninvasive imaging with radiolabeled antisense pharmaceuticals or radiolabeled antisense oligodeoxynucleotide (RASON) probes. Considering the higher stability of phosphorothioate over phosphodiester, the probe stability and tumor localization was compared with both derivatives. METHODS: The 15-mer oligonucleotide sequence was synthesized, aminolinked [sense and antisense phosphodiester (O) and monothioester (S)] and coupled with diethylenetriamine pentaacetate (DTPA)-isothiocyanate and aliquots were lyophilized to make a DTPAAHON kit. The radionuclide 111In was chelated to DTPAAHON derivatives, and free 111In was separated by gel filtration. The radiolabeled antisense and sense probes were injected intravenously in mammary tumor-bearing BALB/c mice (1 x 10(6) cells, 8 days postinoculation). RESULTS: The highest uptake was observed at 2 hr with both thio and oxo derivatives of RASON probes, and small tumors could be imaged noninvasively. Tumor uptake and tumor/blood and tumor/muscle ratios for the sense probe (control) were significantly lower (p < 0.001) than those of the antisense probe. CONCLUSION: The radiolabeled antisense probe may provide a new sensitive tool for noninvasive imaging of c-myc oncogene mRNA for a variety of malignant tumors at an earlier stage.

Animals↗
PubMed1993

Quantitation of thrombogenicity of hemodialyzer with technetium-99m and indium-111 labeled platelets.

The platelet thrombogenicity of a hemodialyzer was quantified with 99mTc- and 111In-labeled platelets. The platelets collected from blood of Beagle dogs, Yorkshire pigs and human volunteers were labeled with 111In-tropolone (detergent-free) and 99mTc-HMPAO. Hemodialysis was performed with a hollow-fiber dialyzer (HFD) in a flow-loop, the temperature of which was maintained at 37 degrees C, with flow-rates of 7, 150 and 270 mL/min; after dialysis, the HFD radioactivity was measured with an ionization chamber and imaged with a gamma-camera. The radioactivity of samples of hollow-fibers taken from the top, middle and bottom of the dialyzer was determined with a gamma-counter. The mean values of hemodialyzer-adherent platelet radioactivity were calculated for both radionuclides. The canine platelets were found to be more thrombogenic than porcine and human platelets. The adhesivity of porcine platelets to the biomaterial (cellulose-acetate) of the dialyzer approximated that of human platelets. The 99mTc label underestimated the thrombus formation (P < 0.01). The dynamic processes of thrombosis and embolization from the hemodialyzer resulted in the large standard deviations around the mean values of the adherent thrombus. In spite of this limitation of the dynamic pathology, the quantitation of comparative thrombogenicity with 111In- and 99mTc-labeled platelets suggests that both radionuclides could be used for measurement of device-induced thrombogenicity and may provide an estimation of prosthesis-induced thrombogenicity of human platelets from animal studies.

Animals↗
PubMed1993

Effects of local geometry and fluid dynamics on regional platelet deposition on artificial surfaces.

An important aspect of blood-material interactions is the activation, adhesion, and subsequent aggregation of blood platelets on the artificial surface, all of which are directly affected by local fluid dynamics. The objective of this work was to directly correlate changing local fluid dynamic conditions produced by various vessel geometries, including stenosis, aneurysm, and separate contraction and expansion geometries, with quantitative in vitro measurements of regional platelet deposition. We directly measured platelet deposition as a function of axial position along four Lexan flow chambers with axisymmetric models of these geometries using 111In-labeled platelets. Platelet deposition was maximum in observed areas of flow recirculation and reattachment and minimum in locations of high shear and separation. For the stenosis geometry, two distinct regions of increased platelet deposition were apparent, one proximal to and one distal to the stenosis throat. An approximately linear increase in platelet densities was produced in the aneurysm region, increasing in the direction of flow. Through a comparison of platelet deposition with local fluid streamline orientation, we have shown that platelet deposition is increased in certain areas due to the enhanced convective transport of platelets and blood cells to the vessel wall along locally curved streamlines with velocity components perpendicular to the vessel wall.

Aneurysm↗
PubMed1990

The kinetics and quantitation of platelet deposition on control (CPC) and heparin-bonded polyurethane angio-catheter (HBPC) with indium-111 labeled platelets in a dog model.

The dynamics of platelet deposition on CPC and HBPC was evaluated with In-111 labeled platelets (In-PLT) with a computerized gamma camera (CGC). Ten non-heparinized dogs (18-25 kg) were catheterized in both femoral arteries with 10 cm of CPC and HBPC (5 Fr., Cordis, Inc.) 24 hours post-injection of 300-420 microcuries of In-PLT, and imaged for 3 hours with gamma camera. The regional platelet deposition on three segments of catheters and puncture site was determined. The catheters were harvested and radioactivity on the catheter segments (proximal: PROX, middle: MID, distal: DIST and puncture site: PS) of both was determined. From the platelet count in blood, radioactivity in blood and segments of catheters, adjacent artery and area of artery and catheter, the platelet-density [X10(3)] (mean +/- S.D.) on catheter and artery were calculated and tabulated: (table; see text) The large standard deviation of retained platelets is due to embolization. The platelet-density and regional counts on catheter segments were lower in the HBPC than CPC. The rate of platelet-deposition was lower in the HBPC than CPC. Most of the thrombi were lost during pullout of the catheter. Both in vivo (dynamic) and in vitro studies were necessary for evaluation of CPC thrombogenicity.

Animals↗
PubMed1989

A mathematical simulation of the AIDS patient and extracorporeal detoxification.

A simple numerical simulation of AIDS patient detoxification by a hypothetical extracorporeal device for the removal of viruses, infected white cells, and syncytia has been designed. The mathematical model accounts for healthy blood white cells attacking and destroying the viruses, while at the same time the viruses attack and infect certain white cells. The infected white cells serve as a site for viral growth; eventually the cells lyse, releasing a large number of viruses into the blood stream. The healthy white cells and infected white cells combine to form syncytia, where the virus multiplies, and finally the syncytium ruptures releasing all the virus. This model can be used to predict concentrations over a specified period for the patient. This is a mathematical model to be used as a research and design tool only.

AIDS-Related Complex↗
PubMedDate not supplied

Kinetics and quantitation of In-111 labeled platelet deposition on control and heparin-bonded polyurethane angio catheters in a dog model.

The dynamics of platelet deposition on control polyurethane catheters (CPC) and heparin-bonded polyurethane catheters (HBPC) were evaluated with In-111 labeled platelets (In-PLT) using a computerized gamma camera (CGC). Ten nonheparinized dogs (18-25 kg) had both femoral arteries catherized with 10 cm of CPC and HBPC (5 Fr.) 24 hr postinjection of 300-420 microcuries of In-PLT, and imaged for 3 hr with a gamma camera. Regional platelet deposition on three segments of catheters and the puncture site was determined. Catheters were harvested and radioactivity on the catheter segments (proximal: PROX, middle: MID, distal: DIST and puncture site: PS) of both was determined. From the platelet count in blood, and radioactivity in blood and segments of catheters, adjacent artery, and area of artery and catheter, the platelet-density [X10(3) (mean +/- S.D.)] on catheter and artery was calculated and tabulated. Proximal values were cath (CPC), 1289 +/- 1125; artery, 1355 +/- 587; cath (HBPC), 125 +/- 113; artery, 1149 +/- 1620. The middle values were cath (CPC), 1102 +/- 1109; artery, 1512 +/- 625; cath (HBPC), 132 +/- 108; artery, 1011 +/- 942. Distal values were cath (CPC), 780 +/- 584; artery, 132 +/- 108; cath (HBPC), 227 +/- 194; artery, 1457 +/- 1309. The puncture site values were cath (CPC), 106 +/- 382; artery, 1011 +/- 942; cath (HBPC), 164 +/- 135; artery, 1498 +/- 1240. The large standard deviation in retained platelets is due to embolization. The platelet-density and regional counts on catheter segments were lower with HBPC than CPC, as was the rate of platelet-deposition.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMedDate not supplied

Quantitation of platelet loss with indium-111 labeled platelets in a hollow-fiber membrane oxygenator and arterial filter during extracorporeal circulation in a pig model.

Platelet consumption in a hollow-fiber membrane oxygenator (HFMO) and arterial filter (AF) during cardiopulmonary bypass (CPB) was quantified in five pigs using Indium-111 labeled autologous platelets. Platelet labeling was performed 20-24 hours before CPB. After general endotracheal anesthesia, the pigs were systemically heparinized and were placed on CPB via a median sternotomy. After 3 hours of CPB, radioactivity was quantified with a gamma camera and an ionization chamber. The percent of injected dose (mean +/- SD) was 0.79 +/- 0.45 in the HFMO, 2.52 +/- 0.93 in AF, 4.3 +/- 1.2 in blood loss during CPB. Platelet consumption in HFMO during CPB was lower than in bubble oxygenators (19%) or silicone membrane oxygenators (12%) as observed in previous studies.

Animals↗
PubMedDate not supplied

Rate constants of embolization and quantitation of emboli from the hollow-fiber oxygenator and arterial filter during cardiopulmonary bypass.

A direct technique was developed to estimate parameters related to half life (T1/2) and rate constants of embolization (RCE) and to quantitate emboli of three sizes (small, medium, and large) shed from the oxygenator and arterial filter during cardiopulmonary bypass (CPB). Cardiopulmonary bypass was performed in 16 Yorkshire pigs divided as follows: systemic heparin group (SHG:6), systemic heparin/heparinized circuit group (SH/HCG:5), and Iloprost (Bentley) (2 ng/kg/min)/heparinized circuit group (IHCG:5) with In-111 labeled autologous platelets. The anesthetized pigs (20-25 kg) underwent CPB at 2.5-3.0 L/min for 3 hours. Pigs were injected with In-111 platelets (300-420 microCi) 24 hours before CPB. Cardiopulmonary bypass was instituted with a roller pump and hollow-fiber oxygenator, and thrombosis and embolization on the oxygenator and filter were monitored by a calibrated Geiger probe (WMB Johnson Associates, Montvale, NJ). The radioactivity in the oxygenator and filter reached peak values at 25-45 min after CPB; the radioactivity then declined in the oxygenator but remained at a steady state in the filter, suggesting continuous embolization at the same rate of trapping. The curve stripping technique of the normalized radioactivity time curve of the oxygenator was used for RCE estimation of different sized emboli shed from the oxygenator; 42% of thrombus embolized from the oxygenator in SHG with three rate constants, with T1/2s of 12 min, 42 min, and 13 hr; the SH/HCG embolized 35% with T1/2 of 78 min, and the IHCG embolized 30%, with a T1/2 of 22 min. This indicates that there is less embolization in the IHCG.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Neutrophil dynamics and retention in lung, oxygenator, and arterial filter during cardiopulmonary bypass in a pig model.

Interactions of neutrophils with adsorbed proteins in components of the cardiopulmonary bypass (CPB) circuit and expression of leukocyte adhesion molecules on activated neutrophils affect neutrophil kinetics and margination. Lung and skeletal muscle along with oxygenator (OX) and arterial filter (AF) in the extracorporeal circuit provide the major areas of neutrophil (N) interaction. The dynamics of N-interaction and N-retention during 3 hr CPB was quantified with autologous In-111 labeled neutrophils (INN) in 4 groups of 20 Yorkshire pigs (28-35 kg, 5 sham; 5 CPB, 1 hr; 5 CPB, 3 hr and 5 CPB with heparinized circuit, 3 hr); anesthetized pigs were injected with INN (500-650 microCi), 30 min before CPB and heparinized, and underwent CPB with a roller pump, a hollow fiber OX (Bentley CM 50, 5.0 m2) and AF (Bentley AF 025, 0.25 m2) at 2.5-3.6 l/min for 3 hr. N-dynamics on OX and AF was monitored by a calibrated Geiger probe. Neutrophil deposition, like that of plasma proteins on OX, reached a steady state almost instantly, but increased on filter with CPB time. INN distribution was viewed with a gamma camera; total INN was measured with an ion chamber and INN in samples of fibers and tissues was quantified with a gamma counter. INN in lung did not change significantly during CPB and increased in liver. The percentage of injected INN in lung, liver, and brain changed with CPB time and showed significant increase over sham-operated animals. Heparin coating of components decreased INN retention. INN/meter2 of lung, OX, and AF at 3 hr were 0.26 +/- 0.07%, 0.06 +/- 0.02%, and 6.17 +/- 3.94%, and significantly lower on a heparin coated filter (2.14 +/- 1.30%). Capillary surface areas of viscera and connective tissues (lung, 100; liver, 134; spleen, 20; heart, 7; skeletal muscle, 92; fat, 12; bone, 3; bone marrow, 5; brain, 0.1 meter2) were estimated from distribution of activated INN in pigs. Lung INN retention was much higher than that of the polymer surfaces of OX/AF, indicating the role of cell adhesion molecules on INN retention on endothelial cells of lung and viscera. By direct continuous monitoring and quantitation of INN at the end of CPB, a sensitive technique for quantitation of neutrophil kinetics, margination, and retention during CPB was developed.

Animals↗
PubMedDate not supplied

Emboli from an extraluminal blood flow hollow fiber oxygenator with and without an arterial filter during cardiopulmonary bypass in a pig model.

The effect of an arterial filter on visceral emboli was quantified with autologous indium-111 labeled platelets (INPLT) during cardiopulmonary bypass (CPB) in Yorkshire pigs. Biodistribution of INPLT was determined in 12 control pigs (30-35 kg, unoperated control [n = 6] and sham operated control [n = 6]). CPB was carried out with (n = 6) and without (n = 6) an arterial filter in 12 pigs at a flow rate of 2.5-3.5 L/min. Platelets labeled with In-111 tropolone (650-780 microCi) were injected intravenously 24 hr before CPB. All pigs were systemically heparinized (activated coagulation time > 400 sec); CPB was instituted with a roller pump, an extraluminal blood flow oxygenator (Bentley Univox, 1.8 m2), and an arterial filter (0.25 m2) and continued for 3 hr. Platelet kinetics, pooling, and counts were monitored by a Geiger probe and a Coulter counter. The thrombi in the oxygenator and arterial filter and emboli in viscera and brain were imaged with a gamma camera and measured with an ion chamber and gamma counter. Percentage of INPLT (mean +/- SD) in organs, tissues, and components of the circuit in four groups of pigs was calculated. Flow cytometry with antibodies to CD61 (GPIIIa) and CD62P (GMP-140: control) of porcine platelets was carried out with blood samples taken before, during, and after CPB for estimation of circulating platelet aggregates and platelet microparticles. Pulmonary, renal, cardiac, and cerebral emboli in pigs undergoing CPB with and without a filter were similar (p < 0.1). The amount of filter adherent thrombi was small (0.04 +/- 0.01%); oxygenator adherent thrombus in both groups was similar (p < 0.1). Emboli were found in the cerebral medulla, hippocampus, and posterior cerebral cortex in both groups. During CPB, the arterial filter functioned minimally as a trap for platelet thrombi detached from the oxygenator and circulating emboli. Flow cytometry of blood demonstrated the shift of equilibria from single platelets to platelet aggregates and microparticles during CPB and their gradual reversal to single platelets after CPB; the loosely adherent emboli disaggregated and further shifted these equilibria to single platelets and smaller aggregates, probably through the action of endogenous nitric oxide and prostacyclin. The emboli were trapped in organs and tissues and microparticles were sequestered by the reticuloendothelial system.

Animals↗
PubMedDate not supplied

Quantification of device adherent, circulating, and organ pool of thrombin and fibrinogen after cardiopulmonary bypass in a pig model.

The pool of thrombin and fibrinogen in circulation, in organs, and on cardiopulmonary bypass devices was quantified during and after cardiopulmonary bypass in four groups of 24 Yorkshire pigs (weight, 30-35 kg); two groups of 10 unoperated pigs were used as controls. Thrombin-alpha and fibrinogen were iodinated with 125iodide using an iodogen transfer technique; 250-300 microCi of these tracers were injected intravenously 1 hr before cardiopulmonary bypass. All pigs were systematically heparinized (activated clotting time > 400 sec); cardiopulmonary bypass was performed at 2.5-3.5 L/min at 28 degrees C using a centrifugal pump, oxygenator (Bentley Univox 1.8 m2; Bentley Inc., Irvine, CA), arterial filter (0.25 m2), and cardiotomy reservoir (BMR 3500) for 90 min, followed by a 90 min reperfusion and 180 min of cardiopulmonary bypass. Iodinated thrombin-alpha and fibrinogen in intact organs and samples of blood, organs, tissues, and oxygenator-arterial filter-cardiotomy reservoir were quantified with an ion chamber and a gamma counter, respectively. The percent of injected iodinated thrombin-alpha and fibrinogen dose (mean +/- SD) in organs and cardiopulmonary bypass devices of all groups of cardiopulmonary bypass pigs was calculated. Thrombin generated at the small area of surgical wounds (0.016-0.038 m2), and fibrin deposited on surfaces of cardiopulmonary bypass devices (2.59 m2), initiate and propagate thrombus formation and embolization. The protein level reached saturation values on all cardiopulmonary bypass devices at 180 min. High levels of thrombin and fibrinogen-fibrin circulate in blood and organs, and are adsorbed on cardiopulmonary bypass devices; this large blood pool of pro-coagulants in the cardiac cradle, tissues, and perfused organs may account for thrombi and emboli during and after cardiopulmonary bypass.

Adhesiveness↗
PubMedDate not supplied

Quantitation of comparative thrombogenicity of dog, pig, and human platelets in a hemodialyzer.

Comparative platelet thrombogenicity was quantified with In111 labeled platelets. The platelets collected from the blood of Beagle dogs, Yorkshire pigs, and human volunteers were labeled with detergent free In111 tropolone, and sham hemodialysis (SHD) was performed with a hollow fiber dialyzer in a flow loop at 37 degrees C, with flow rates of 7, 150, and 270 ml/min. After SHD, hemodialyzer radioactivity was measured with an ionization chamber, gamma counter, and it was imaged with a gamma camera. The mean values of hemodialyzer-adherent platelet radioactivity were calculated. Canine platelets are more thrombogenic than porcine and human platelets. Quantitation of comparative thrombogenicity with In111 platelets may provide an estimation of prosthesis induced thrombogenicity of human platelets from animal studies.

Animals↗