Biomedical subjects

B Klitzman

Publications and source records attributed to B Klitzman.

At least 19 recordsLinked to original sources

PubMed1998

Engineering the tissue which encapsulates subcutaneous implants. II. Plasma-tissue exchange properties.

This study assesses the plasma-tissue exchange characteristics of the capsular tissue that forms around implants and how they are affected by implant porosity. The number of vessels and their permeability to rhodamine were measured by intravascular injection of the fluorophore tracer into Sprague-Dawley rats that hosted for 3-4 months polyvinyl alcohol (PVA) and polytetrafluoroethylene (PTFE) subcutaneous implants. Rats were implanted with four pore sizes of PVA--a nonporous PVA (PVA-skin), and 5, 60, and 700 micron mean pore sizes (PVA-5, PVA-60, and PVA-700, respectively)--and two pore sizes of PTFE: 0.50 (PTFE-0.5) and 5.0 (PTFE-5) mean micron pore sizes. Photodensitometric image analysis was used to quantify the local tracer extravasation and, hence the permeability coefficients of isolated vessels around the implants. The number of functional vessels within 100 microm of the implants highlighted by the lissamine-rhodamine tracer were counted with fluorescence microscopy and with H&E stained sections using brightfield microscopy. The permeability of vessels did not vary substantially with implant pore size but generally were lower than those measured for surrounding subcutis. Pore size, however, had a dramatic effect on the vascular density of tissue-encapsulating implants: the number of microvessels (under 10 microm in radius) within the tissue surrounding the porous implants was higher than the number around nonporous implants. Pore sizes on the order of cellular dimensions incited optimal neovascularization; the vascular density around PVA-60 implants was six times higher (p < .001) and three times higher (p < .001) than those around PVA-0 implants in the fluorescent images and in brightfield, respectively. Moreover, brightfield microscopy showed the number of vessels around PVA-60 implants was almost double those in normal subcutis. The results suggest that optimal vascular density around long-term implants, such as sensors, biofluid cell constructs, and immunoisolated cell systems, may be engineered with pore size.

Animals↗

PubMed1998

Engineering the tissue which encapsulates subcutaneous implants. III. Effective tissue response times.

The results of two previous studies have shown that implant porosity can be used to increase both the measured diffusion coefficients and the vascularity within the tissue encapsulating long-term subcutaneous implants. This study investigates the hypothesis that the analyte concentrations within the tissue surrounding porous implants will respond more quickly to changes in plasma levels than does the densely packed, avascular fibrous capsule surrounding nonporous implants. The average concentration of lissamine-rhodamine was measured in tissue within 100 microm of the following implants at four different times following injection of the tracer: PVA-skin, PVA-5, PVA-60, PVA-700 (polyvinyl alcohol nonporous, 5 microm, 60 microm, and 700 microm mean pore sizes, respectively) and PTFE-0.5 and PTFE-5 (polytetrafluoroethylene 0.5 microm and 5 microm mean pore sizes, respectively). The results were compared to those of unimplanted subcutaneous tissue (SQ). In addition, the data were analyzed with a simple two-compartment model in which a tissue response time constant (taup) was extracted. As in the case of vascular density, the cellular dimension of the PVA-60 pore sizes produced surrounding tissue with the optimum response times to changes in plasma concentrations. The concentrations of rhodamine within the tissue surrounding the PVA-60 implant were the highest at all time points and responded to the change in plasma rhodamine concentration approximately three times more quickly (taup = 764 s) than the fibrous tissue encapsulating the nonporous PVA-skin (taup = 2058 s) and more than twice as quickly as SQ (taup = 1627 s). The overall mass transfer rate between plasma and the tissue surrounding the different implants calculated from the permeability and density of vessels from the previous study correlated very well (r2 = 0.7, p < .02, slope of 0.98) with the reciprocal of the tissue response time constant (taup).

Animals↗

PubMed1998

Improved microsurgical anastomotic patency with low molecular weight heparin.

Blood flow to a free flap may be impaired by thrombotic occlusion at the anastomosis or by microemboli occluding microvessels. The purpose of this study was to test the hypothesis that unfractionated heparin (UFH) or low molecular weight fractions of heparin (LMWH) could improve both the patency of microvascular anastomoses and microcirculatory perfusion. Sixty-six rats underwent orthotopic elevation of 3- x 10-cm epigastric free flaps. Animals received a single injection of either vehicle, UFH or LMWH, prior to microvascular clamp application and pedicle division. Anastomotic patency and tissue survival area were assessed on postoperative day 7. Anastomotic patency was significantly improved in both the UFH and LMWH groups. Total tissue survival area in those flaps with anastomotic patency was significantly improved in the UFH and the LMWH groups. Although both UFH and LMWH significantly elevated activated partial thromboplastin times (APTT) and anti activated clotting factor X (anti-Xa) activity over controls, UFH had its greatest effect on APTT, and LMWH on anti-factor Xa activity. Hematomas developed only in the UFH group. Thus, although both UFH and LMWH improved microcirculatory perfusion, as indicated by increased flap survival, only LMWH improved anastomotic patency while minimizing hemorrhage.

Anastomosis, Surgical↗

PubMed1998

Comparison of supine and lateral positioning on various clinically used support surfaces.

In this study, interface pressures, transcutaneous oxygen tension (TcPO2), and blood flow were compared with the classic pressure ulcer-prone areas in the supine and lateral position on six different high- and low-air-loss support surfaces. Interface pressures were substantially higher in the lateral decubitus than in the supine position. Consistent with this, mean TcPO2 and blood flow readings over the trochanter in the lateral position were lower than over the sacrum and ischium in the supine position. With weighting, the average TcPO2 readings decreased from 78.6 mmHg to 11.9 mmHg on the trochanter and from 65.4 mmHg to 45.7 mmHg on the sacrum and ischium. In parallel, average laser Doppler readings decreased from 2.3 to 0.7 laser Doppler flow units over the trochanter, but did not change significantly over the sacrum and ischium. These data support the clinical suggestion that the lateral decubitus position should not be maintained for long periods of time, not even on many special support surfaces.

Adult↗

PubMed1998

Heparin bonding increases patency of long microvascular prostheses.

The high thrombogenicity of synthetic biomaterials has limited their use for reconstructive microsurgery. Prime factors in the thrombogenicity of synthetic materials in contact with blood include gas nuclei at the blood gas interface as well as the inherent thrombogenicity of the materials themselves. Expanded polytetrafluoroethylene (ePTFE) vascular prostheses were denucleated by placement in acetone and ethanol followed by degassed saline or by placement in degassed saline subjected to hydrostatic pressure. Heparinized grafts were prepared by coating with tridodecylmethylammonium chloride (TDMAC), followed by immersion in heparin. Grafts were installed to reconstruct the femoral artery (1 x 10 mm) or as renal-iliac bypasses (1 x 50 mm) in rats. In the femoral artery reconstruction model, control grafts thrombosed within 10 minutes of implantation. All acetone denucleated femoral grafts remained patent for 60 minutes but were occluded at day 1. All pressure denucleated femoral grafts remained patent for 60 minutes, whereas six were patent at 1 month. In contrast, 11 of 15 heparinized femoral grafts were patent at 1 month. In the renal iliac bypass model, all control grafts were thrombosed within 10 minutes, whereas all heparin bonded grafts remained patent at 1 month. This finding confirms that removal of air from small diameter ePTFE grafts decreases acute thrombogenicity and that heparin bonding further decreases thrombogenicity, suggesting that clinically useful lengths of microvascular prostheses may be possible.

Anastomosis, Surgical↗

PubMed1998

Multimodality evaluation of pressure relief surfaces.

Multimodality evaluation of six different support surfaces was performed measuring interface pressure, transcutaneous oxygen tension, and blood flow in pressure ulcer-prone areas on healthy subjects. Interface pressure was measured with a flexible force-sensing resistor array. The interface pressure distribution patterns of 10 healthy male volunteers were measured in the supine and lateral positions using a pressure sensor (force sensing resistor) array. Transcutaneous oxygen (TcPO2) and laser Doppler flowmeter probes were placed over the sacrum, the right trochanter, and the right ischium. Data were recorded for 15 minutes each with the subject in the supine and lateral decubitus positions. Statistically significant differences (p < 0.05) between the various surfaces could be observed for blood flow and pressure measurements, especially in the lateral position over the trochanter and for the TcPO2 measurements in the supine position over the sacrum. We conclude that measuring interface pressure, transcutaneous oxygen tension, and blood flow allows a more thorough evaluation of the physiologic effects of special support surfaces than any single technique. Future studies on patients will assess algorithms for using these measurement techniques to predict the efficacy of various support surfaces in minimizing pressure ulceration.

Blood Gas Monitoring, Transcutaneous↗

PubMed1998

Improving endothelial cell adhesion to vascular graft surfaces: clinical need and strategies.

Synthetic vascular grafts do not spontaneously endothelialize in humans and require some form of anticoagulation to maintain patency. Preseeding synthetic graft materials such as expanded polytetrafluoroethylene (ePTFE) and polyethylene terephthalate (PET) with endothelial cells (EC) has been examined in various in vitro and in vivo models. Although various studies provide encouraging results, clinical trials for EC seeding on synthetic grafts have not been equally successful. This paper provides a brief review of the various reports on EC seeding in animal and clinical studies. We discuss the inefficiencies associated with the EC seeding process and examine plasma protein treatment of the graft surfaces as a viable option for improving EC attachment, retention and spreading. As an alternative to existing therapies we present data on a heterogeneous ligand treatment of fibronectin (Fn) and avidin-biotin for enhanced human umbilical vein endothelial cell (HUVEC) adhesion to ePTFE graft surfaces. Control consisted of HUVECs seeded on Fn treated ePTFE graft surfaces. Functionality of HUVECs was assessed by measuring prostacyclin production of cells on both homogeneous and heterogeneous ligand treated surfaces. Laminar flow studies with a variable width flow chamber and scanning electron microscopy were used to measure initial cell retention and observe initial cell spreading on ePTFE surfaces, respectively. HUVEC retention on heterogeneous ligand treated graft surface was significantly (p < 0.001) higher compared to homogeneous ligand treated surfaces for shear stress in the range of 10-30 dyn cm(-2). HUVEC showed more cellular spreading on the heterogeneous ligand treated surface after seeding for 1-2 h. In vivo experimentation was performed in immune deficient (nude) rats by replacing a section of both the femoral arteries with 8 mnm long, 1 mm internal diameter denucleated ePTFE grafts treated with homogeneous and heterogeneous ligands respectively. Both grafts were seeded with similar cell density for 15 min prior to implantation. EC attachment and retention was measured by staining EC with hematoxylin and counting the cells before and after flow using light microscopy. The results indicate that a heterogeneous ligand treatment of graft surfaces using avidin-biotin and Fn-integrin attachment mechanisms increase cell seeding efficiency, initial cell retention and cellular spreading.

Adsorption↗

PubMed1998

Pressure ulcers and pressure relief surfaces.

Pressure ulcer incidence has been reduced but not eliminated. A few patients still develop pressure ulcers despite using air-fluidized beds and other specialty beds. In the future, very high-risk patients may possibly be sent to space clinics to recuperate in zero gravity for extended periods. Another possibility is the creation of suspension devices to keep a patient off the areas of the body where pressure sores might occur. Being informed of what is available and and aware how to use it optimally is currently the best solution.

Humans↗

PubMed1997

Engineering the tissue which encapsulates subcutaneous implants. I. Diffusion properties.

This report uses normal rat subcutis as a reference point to provide a quantitative analysis of small analyte transport through the tissue which encapsulates implants. Polyvinyl alcohol (PVA) with 60- and 350-micron mean pore size (PVA-60, PVA-350), nonporous PVA (PVA-skin), and stainless-steel cage (SS) specimens were implanted in the subcutis of Sprague-Dawley rats for 4 weeks to elicit a range of capsular wound-healing tissues. Histologic examination showed that the capsular tissue which formed around PVA-skin and SS specimens was densely fibrous and avascular. That forming around PVA-60 and PVA-350 was less densely fibrous and more vascular. The fibrous content of capsular tissue and subcutis was determined from eosin-stained histologic sections. Dual-chamber diffusion measurements of sodium fluorescein (Mw 376 g/mol) through capsular tissue and normal rat subcutis were used to quantitatively compare the effective diffusion coefficients of small analytes on the order of glucose. The two most fibrous capsular tissues exhibited diffusion coefficients that were statistically (p < 0.05) less than that determined for rat subcutis by 50 and 25% for PVA-skin and SS, respectively. The diffusion coefficients of the less dense capsular tissue which formed around the porous implants were not statistically different from subcutis. The experimentally measured diffusion coefficients of the two most fibrous capsular tissues were closely predicted by a simple two-component diffusion model consisting of an aqueous interstitium with an array of impenetrable bodies equal in volume fraction to the fibrous content of the tissue. This model overestimates the diffusion coefficients measured for the least fibrous tissues. Using the diffusion coefficient measured for the PVA-skin capsular tissue, a finite difference model predicts that a 200-microns-thick capsular layer would increase from 5 to 20 min the time required for subcutaneously implanted sensor to detect 95% of the blood analyte concentration. This study suggests that the fibrous capsule forming around a subcutaneously implanted smooth-surface sensor imposes a significant diffusion barrier to small analytes such as glucose, thus increasing the lag time of the sensor by as much as threefold. A corollary observation is that a sensor with a porous surface which allows tissue ingrowth may be more responsive to blood analyte fluctuations as a result of its a more vascular and less fibrous encapsulation tissue.

Animals↗

PubMed1997

Heparin coating of vascular prostheses reduces thromboemboli.

BACKGROUND: Synthetic conduits made from currently available materials are suboptimal for use in small-diameter vascular reconstruction because of their high surface thrombogenicity, which leads to failure. METHODS: In this study control, heparin-irrigated, or heparin-bonded expanded polytetrafluoroethylene (ePTFE) grafts (4 mm long by 1 mm inner diameter) were implanted to reconstruct the iliac artery in male rats. The cremaster muscle was isolated as an island flap based on branches of the iliac artery downstream from the graft. Emboli were quantitated by using intravital fluorescent microscopy of the cremaster muscle's microcirculation. RESULTS: The mean number of emboli observed per animal during a 20-minute period was 91 for the control group, 84 for the heparin-irrigated group, and 22 for the tridodecylmethylammonium chloride (TDMAC)-heparin group. The mean area of each embolus was 1057 microns 2 for control, 940 microns 2 for heparin-irrigated, and 808 microns 2 for TDMAC-heparin-coated grafts (p < 0.05 for TDMAC-heparin versus control or heparin-irrigated). CONCLUSIONS: A TDMAC-heparin coating of ePTFE microvascular prostheses significantly reduces downstream microemboli.

Animals↗

PubMed1997

Laser Doppler flowmetry: a clinical test of pulpal vitality.

PROBLEM: A rapid, accurate, noninvasive method of determining pulpal blood flow would be helpful in determining pulpal vitality. OBJECTIVE: The purpose of this study was to determine if laser Doppler flowmetry can measure induced changes in pulpal blood flow. STUDY DESIGN: Two percent lidocaine with epinephrine 1:100,000 was infiltrated into the labial vestibule to anesthetize five anterior teeth in healthy human volunteers. Stents were placed on the teeth to stabilize the laser Doppler probes. Measurements of pulpal blood flow were made along with electrocardiograms to record the cardiac cycle. RESULTS: Laser Doppler flowmetry demonstrated pulpal blood flow and pulse amplitude decreases under test conditions. These decreases were most significant at 10 minutes after the injection of anesthetic with vasoconstrictor. CONCLUSIONS: Laser Doppler flowmetry was able to measure pulpal blood flow and record changes in blood flow that occurred when epinephrine was used with infiltration anesthesia. The pulse width and the mean flow were dramatically affected as was synchronization with the cardiac cycle.

Analysis of Variance↗

PubMed1997

Iloprost in alginate decreases the thrombogenicity of expanded polytetrafluoroethylene.

Vascular prostheses of small diameter perform poorly in vivo, in part because of the high thrombogenicity of available biomaterials. This study examined the thrombogenicity of expanded polytetrafluoroethylene (ePTFE) vascular graft segments (10 mm long x 4 mm i.d.) in vitro before and after impregnation with saline, alginate, or alginate containing the stable prostacyclin analog, iloprost. Each segment was immersed in activated whole blood and the weight of the adherent thrombus was measured at specified intervals. At 6 and 7 min the saline-denucleated group accumulated significantly less thrombus than control (p < .05). Alginate alone was not significantly different from controls. The graft segments treated with alginate + iloprost accumulated significantly less thrombus (p < .05) than all other groups after 6 min. These data demonstrate that denucleation of ePTFE with iloprost in alginate dramatically decreases its in vitro thrombogenicity.

Alginates↗

PubMed1997

Modulation of ultraviolet light-induced epidermal damage: beneficial effects of tocopherol.

Oxygen free radicals have been shown to result from and mediate deleterious effects of ultraviolet radiation on the skin. The purpose of this study was to determine if topical DL-alpha-tocopherol (vitamin E) could reduce ultraviolet-induced damage to the epidermis. Twenty mice were treated with either ethanol or a 1:1 mixture of tocopherol and ethanol. Treatments consisted of once-daily 0.1-ml topical applications for 1 week, followed by irradiation with 0.30 mW/cm2 of ultraviolet B irradiation. A statistically significant decrease in Schiff base formation was noted between tocopherol-treated animals and their controls. Histologic study revealed a statistically significant increase in epidermal thickness in tocopherol-treated skin versus controls or vehicle alone. The thicker epidermis was accompanied by the presence of parakeratosis, implicating increased proliferation as the cause of the increasing thickness. The number of sunburn cells was decreased by tocopherol treatment. Tocopherol protection from ultraviolet irradiation may have been due to both direct protection from free radicals and indirect protection by means of increased epidermal thickness. The demonstration of beneficial effects of tocopherol administration suggests that further studies in clinically relevant models to define optimal dosage, frequency of administration, vehicle, and quantitation of the possible protective effects afforded to Langerhans cells may be useful.

Administration, Topical↗

PubMed1997

Brown recluse spider envenomation: a prospective trial of hyperbaric oxygen therapy.

OBJECTIVES: Loxosceles reclusa (brown recluse) spider bites can produce severe skin lesions that may necessitate extensive surgical repair. This study delineated the effects of hyperbaric oxygen (HBO) therapy on these lesions by performing a prospective controlled animal study. METHODS: After approval by the Institutional Animal Care and Use Committee, 41 New Zealand white rabbits received 64 intradermal injections of 73 microL of raw venom extract mixed with physiologic buffered saline (Dulbecco's solution). Control injections were made with buffer. The animals were divided into 5 groups: 1) venom and no HBO; 2) venom and 1 immediate HBO treatment (100% O2); 3) venom and immediate HBO with 10 treatments (100% O2); 4) venom and then delayed (48 hr) HBO therapy with 10 treatments (100% O2); and 5) venom and immediate hyperbaric treatment with normal inspired PO2 for 10 treatments (8.4% O2). Three animals in group 2 also received a control sodium citrate buffer injection. HBO treatments were at 2.5 atm absolute (ATA) for 90 minutes twice daily. Daily measurements were made of the lesion diameter, and skin blood flow using a laser Doppler probe. RESULTS: There was no significant effect of HBO on blood flow at the wound center or 1-2 cm from the wound center. Standard HBO significantly decreased wound diameter at 10 days (p < 0.0001; ANOVA), whereas hyperbaric treatment with normoxic gas had no effect. Histologic preparations from 2 animals in each group revealed that there were more polymorphonuclear leukocytes in the dermis of all the HBO-treated animals when compared with the venom-alone and sodium-citrate controls. CONCLUSION: HBO treatment within 48 hours of a simulated bite from L. reclusa reduces skin necrosis and results in a significantly smaller wound in this model. The mechanism appears unrelated to augmented local blood flow between treatments.

Animals↗

PubMed1996

Pulpal response to cavity preparation with the Er:YAG and Mark III free electron lasers.

OBJECTIVE: The purpose of this investigation was to evaluate the pulp response to class V cavity preparation with the use of the Er:YAG laser and free electron laser. STUDY DESIGN: Class V cavities were prepared in 133 teeth of four beagle dogs by one of three methods: (1) Er:YAG laser, (2) free electron laser, (3) high-speed handpiece. Treatment occurred at 1 hour, 1 day, 7 days, and 28 days. The teeth were removed and the pulp evaluated. Histologically, the data were evaluated with Mantel-Haenszel analysis. RESULTS: The Er:YAG laser, free electron laser, and handpiece treatment groups resulted in specimens with normal or mild pulp reactions in 36, 46, and 42 teeth, respectively; moderate or severe reactions were observed in 7, 1, and 1 teeth, respectively. No statistically significant difference in the pulp response to the three treatment modalities was observed. CONCLUSION: The pulp response to Er:YAG laser and free electron laser application would appear to be similar to the response from high-speed handpiece application.

Animals↗

PubMed1996

Limiting impairment of muscle function following ischemia and reperfusion in rabbits.

Reperfusion injury is a phenomenon complicating microvascular reconstruction. Extensive investigations of free-radical scavengers exist in the literature. The potential beneficial effects of verapamil, deferoxamine, and dimethylsulfoxide were studied in the rabbit forelimb subjected to 3 hr of tourniquet ischemia, followed by a period of reperfusion. Five minutes prior to tourniquet release, rabbits were given single intravenous infusions of normal saline, verapamil (0.2 mg/kg), deferoxamine (50 mg/kg), or dimethylsulfoxide (100 mg/kg). Following reperfusion, neither light microscopy nor laser Doppler flowmetry revealed significant differences between the sham and treated limbs. Muscle function was evaluated by measuring maximal twitch tensions in the flexor digitorum superficialis. Deterioration of muscle contractile function at 0.5, 3, and 24 hr after reperfusion was significantly improved by treatment with verapamil or deferoxamine. Conversely, dimethylsulfoxide worsened muscle function post ischemia. Dimethylsulfoxide does not appear to be beneficial, while verapamil and deferoxamine may be of benefit in mitigating reperfusion injury in microvascular transplantation.

Animals↗

PubMed1996

Microsurgical composite tissue transplantation at difficult recipient sites facilitated by preliminary installation of vein grafts as arteriovenous loops.

In microvascular surgery when local recipient vessels are inadequate, vein grafting is required. There are several potential inherent disadvantages of immediate vein grafting, including the development of graft thrombosis or leakage, an increased opportunity for technical errors, and an increased number of anastomoses in series. All of these may contribute to a higher failure rate for composite-tissue transplantation requiring vein grafts. The authors hypothesized that in cases where vein grafting is obviously required, the creation of a temporary, looped, arteriovenous fistula (AVF) would reduce the morbidity of vein grafting, by allowing the detection of thrombosis or technical errors predisposing to thrombosis prior to free-tissue transplantation. Since delaying the division of an AVF for 5 or more days may allow time for healing of the endothelium at the AVF anastomotic site, the hypothesis was that composite-tissue transplantation whose vein grafts were installed as an AVF divided in a delayed manner, might have better patency than those in which vein grafts were installed at the time of reconstruction. This study reviews the results of 16 patients (8 females, 8 males) who underwent 17 microvascular reconstructions using AVFs. Patient courses and outcomes were compared between those undergoing immediate (8 patients) and delayed (7 patients) AVF construction, division, and free-tissue transplantation. There was a low patency rate for AVFs which were divided in a delayed fashion (2 of 7 patients, 29 percent), compared with those which were immediately divided (10 of 10, 100 percent). These results suggest that, in spite of a strong theoretical basis for delayed division of the AVF, delayed harvesting of the AVF is empirically associated with a higher thrombosis rate (p = 0.0048, Fishers exact test).

Adolescent↗

PubMed1995

Assessments of thrombogenicity by three in vitro techniques. Student Research Award in the Undergraduate, Master Candidate, or Health Science Degree Candidate Category, 21st annual meeting of the Society for Biomaterials, San Francisco, CA, March 18-22, 1995.

This study assessed three in vitro techniques designed to measure the thrombogenicity of vascular grafts. All techniques immersed vascular grafts in rotating blood. In the gravimetric analysis, the weight of adherent thrombi was recorded at 2 min intervals for 20 min. In the torque analysis, a microviscometer continuously recorded the amount of torque developed as the graft rotated for 20 min. In the thrombin analysis, the blood sample was analyzed for fibrinopeptide A production indicating fibrinogen cleavage. Expanded polytetrafluoroethylene grafts were treated by removal of air nuclei (denucleation), binding of heparin, or binding of polyethylene oxide (PEO). The gravimetric analysis determined that the time at which each group experienced clot initiation was as follows: control after 6 min, denucleation after 14 min, heparin after 18 min, and PEO after 10 min. Similarly, in the torque analysis all treatment groups significantly delayed the initial increase in torque from 8.0 min for control to 12.5 min for denucleation (P < .01), > 20 min for heparin (P < .01), and 12 min for PEO (p < .05). The thrombin analysis determined that coagulation activity was reduced relative to control at 12 min with the denucleation group (P < .05) and heparin group (P < .01) and at 18 min with all treatment groups (P < .01). The similarity of results among the techniques increases confidence that each measurement accurately predicts in vitro thrombogenicity.

Awards and Prizes↗