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Background: Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is a well-established treatment for severe cardio-pulmonary failure. The use of large bore cannulas in the femoral vessels for an extended period has been associated with significant wound complications. There is a lack of data analyzing risk factors that can mitigate such complications. The primary purpose of this study was to identify modifiable risk factors associated with femoral wound complications after VA ECMO decannulation., Methods: Retrospective analysis of wound complications in patients following VA ECMO decannulation from 2014-2021 at a single academic institution were analyzed. Wound complications were defined as wound infection, dehiscence, or those wounds that were deliberately opened to promote healing by secondary intention., Results: Sixty patients underwent decannulation of VA ECMO with operative repair of the femoral artery. Fifteen patients were identified to have wound complications, eight (53%) of these had infection. Fourteen (93%) patients had wound dehiscence or had their wound purposely opened at bedside. Univariate analysis revealed no association of access-related complication with higher Body Mass Index (BMI, 28.3 vs. 32.7 kg/m 2 , P=0.110) but here was a trend in having more wound complications in individuals with COVID-19 infection (6.7% vs. 26.7%, P=0.058). Patients that had dual cannulation with the arterial and venous cannulas in the same groin had significantly more wound complications compared to single cannulation arterial and venous cannulas in separate groins (57.8% vs. 93.3%; P=0.012). Multivariate analysis revealed same side cannulation (OR 18.05, 95% CI 1.44-226.18, P=0.025) and COVID-19 infection (OR 18.18, 95% CI 1.50-220.66, P=0.023) were independent predictors of wound complications., Conclusions: Wound complications after VA ECMO decannulation is associated with COVID-19 infection and having venous and arterial cannulas in the same groin. We recommend that the arterial and venous cannulation be placed in different groins in patients that require VA ECMO. more...

Background: Although aortoiliac occlusive disease (AIOD) is preferentially treated endovascularly, some patients are still better served with an aortobifemoral bypass (ABF). For those patients, surgical treatment options include both standard open operations as well as laparoscopic ABF (LapABF). Several European centers perform LapABF with favorable results instead of open surgery, but this has not been widely embraced in the United States. We reviewed our ten-year experience with LapABF, evolving from a completely laparoscopic to a standardized laparoscopic-assisted approach., Methods: A retrospective review of all laparoscopic aortic operations performed at a single US academic institution from 2005 to 2015 was completed. Demographics, co-morbidities, intraoperative parameters and clinical outcomes were recorded. Patients were excluded from consideration for laparoscopic surgery if they had previous aortic surgery, aneurysmal disease or gastrointestinal pathology (e.g. diverticulitis or an enteric stoma)., Results: Thirty men and sixteen women were treated, (n=46) with a mean age of 55.7 (range 38-75 years). All operations were performed by a single surgeon. LapABF was successfully completed in 95.6%. A completely laparoscopic approach was undertaken in eight patients and a laparoscopic-assisted approach was used in the remaining 38 patients. Mean follow-up was 46 months (range 1 to 131). The indication for operation was claudication (n=35, 76%), rest pain (n=8, 17%) or tissue loss (n=3, 7%). Twenty-one limbs had a history of a prior failed aortoiliac endovascular intervention (23%). Median length of stay was 6 days (range 2-30). Within 30 days there were two myocardial infarctions (4.3%), one transient ischemic attack (2.2%) and one death (2.2%). Re-intervention was performed in 12 patients over the course of the study period (26.1%). Primary, primary-assisted and secondary patency was 79.4%, 93.9% and 94.9% at 60 months, respectively. Overall mortality was 17% with a mean duration of follow-up of 60 months (range 1-116). Multivariable analysis revealed coronary artery disease (CAD; P=0.03) conferred a sixteen-fold risk for death during long-term follow-up., Conclusions: In this large US series of LapABF, we observed acceptable long-term patency, short length of stay and minimal morbidity. We suggest that this standardized approach for laparoscopic-assisted ABF is a viable option for patients with AIOD not suitable for endovascular therapy. The use of laparoscopic-assisted ABF affords practitioners the benefits of a completely laparoscopic approach while reducing the duration and complexity of the operation. Given the rate of re-interventions in the early era practitioners should be aware of the learning curve with this approach. more...

Objective: The objective of this study was to report 30-day results from a prospective, nonrandomized, multicenter trial that evaluated the safety and effectiveness of the Zenith Alpha thoracic endovascular graft (Cook Medical, Bloomington, Ind) for treatment of blunt thoracic aortic injuries (BTAIs)., Methods: Eligible patients with BTAIs (grade II to grade IV) in the descending thoracic aorta were treated with the Zenith Alpha device, which is available in smaller graft diameters (starting at 18 mm) and lower profile delivery systems (starting at 16F) than currently available thoracic endografts. The device (nitinol stents and polyester graft material) accommodates a tighter aortic curvature (radius of 20 mm) than the predicate Zenith TX2 Pro-Form. Follow-up clinical and imaging evaluations were performed at 30 days, at 6 and 12 months, and annually thereafter through 5 years. The primary end point was 30-day mortality., Results: Between January 2013 and May 2014, 50 patients (44 men; mean age, 43 ± 19 years; range, 18-89 years) were treated with the Zenith Alpha device at 17 U.S. sites. The mean Injury Severity Score was 31 ± 14 (range, 3-66). Technical success was achieved in 100% of patients, with 0% intraoperative mortality. Device access was entirely percutaneous in 22 patients (44%). Smaller size grafts (18-24 mm) were used in 15 patients (30%). The mean procedure time was 85 ± 44 minutes (range, 34-278 minutes), and mean blood loss was 103 ± 145 mL (range, 0-1000 mL). The 30-day mortality rate was 2%; one patient died 24 days after the procedure of respiratory failure related to associated injuries and not to the device or procedure as adjudicated by an independent Clinical Events Committee (CEC). One patient experienced a stroke 7 days after the procedure (cause undetermined by the CEC), and one patient underwent reintervention for a site-reported proximal type I endoleak (core laboratory reported unknown endoleak type) at 30 days after the procedure. There have been no conversions to open surgical repair, paraplegia, or aortic rupture within 30 days., Conclusions: Short-term results indicate that the Zenith Alpha thoracic endovascular graft appears safe and effective for the treatment of BTAIs. This low-profile device enables complete percutaneous repair in a large percentage of patients and can achieve high rates of technical success and very low rates of aortic injury-related mortality within 30 days., (Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.) more...

Objective: To evaluate the safety and effectiveness of the conformable GORE TAG thoracic endoprosthesis (CTAG) device (W. L. Gore and Associates, Flagstaff, Ariz) for the endovascular repair of traumatic aortic transections., Methods: A prospective, nonrandomized, multicenter trial was conducted at 21 sites. Primary safety end points included 30-day all-cause mortality. The effectiveness end point was freedom from a major device event requiring reintervention through 1-month follow-up., Results: Fifty-one subjects were enrolled between December 2009 and January 2011 with polytraumatic injuries and a mean Injury Severity Score of 32 ± 14. The proximal mean intimal aortic diameter measured 24 mm, while the mean distal intimal diameter was 22 mm. A total of 57 CTAG devices were implanted (mean, 1.1/subject; range, 1-2) with a mean patient age of 44 years (range, 21-87) and a male-to-female ratio of 2:1. Technical success was 100% with an operative mortality of 0%. Femoral access was utilized in 96% of patients. The mean procedure time and blood loss was 105 minutes and 148 mL, respectively. All subjects required admission to an intensive care unit with a mean hospital stay of 14.6 days. Adjuvant techniques (ie, lumbar drains and induced hypertension) to prevent paraplegia were used in only 7.8% of patients. No patient developed paraplegia despite 63% having complete or partial left subclavian artery coverage and only 9% of those receiving left subclavian artery revascularization. In addition, there were no device compressions or major device events reported. Overall mortality at 30 days was 7.8%, and all were adjudicated by the clinical events committee as not being device or procedure related. Serious adverse events occurred in 39.2% of patients through 30 days. To date, there have been no conversions to open repair. Two site-reported endoleaks were detected during the mean follow-up of 4.2 months, which did not require reintervention., Conclusions: The CTAG device was demonstrated to be a safe and effective treatment for traumatic aortic transection based on 30-day outcomes. There were no device-related serious adverse events., (Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.) more...

A significant portion of the morbidity associated with a thoracoabdominal approach to the suprarenal aorta is due to postoperative pulmonary dysfunction. A contributing factor to this dysfunction is division of the diaphragm during surgical exposure and subsequent repair upon completion of the operation. In this brief technical report, we describe a novel technique using a gastrointestinal stapler to divide the diaphragm that is rapid, hemostatic, and aids with reapproximation at the completion of the case. This method of diaphragm division is quicker and less traumatic and has the potential to decrease the incidence of postoperative pulmonary dysfunction., (Published by Elsevier Inc.) more...

Background: Isolated limb infusion (ILI) for the treatment of in-transit melanoma was originally described more than 10 years ago. Response rates of 45-53% have been reported in U.S. series. Long-term quality of life outcomes after this procedure have not been described. We hypothesized that ILI is rarely associated with long-term limb morbidity., Methods: ILIs performed at our institution between July 2005 and June 2009 were reviewed. Patients were contacted cross-sectionally at 2 time points. During these interviews, response to treatment and postoperative limb function were assessed., Results: Thirty-two ILIs were performed during the time period. Twenty-seven patients were treated for in-transit melanoma; 5 were treated for recurrent Merkel cell carcinoma. The 30-day mortality was 0%. Three patients (9%) required fasciotomy. Durable complete responses were achieved in 41% of patients, with mean follow-up time of 19.4 ± 9.6 months after infusion; after this period, 53% reported progression of disease. The most common postprocedure symptoms were edema (88%), numbness (59%), and pain (59%). By 3 months and at the time of last follow-up, the most common symptoms were edema (82%), numbness (65%), and stiffness (35%). No patients reported impaired limb function at the time of last follow-up compared to baseline. Median survival was 19.2 ± 4.2 months after infusion., Conclusions: ILI for melanoma and Merkel cell carcinoma is associated with postprocedure symptoms in most patients, most commonly edema, color change, and numbness. At last follow-up, no ILI patients had residual functional impairment in the treated limb. more...

Background: Surgical trainees face many obstacles in learning basic surgical anatomy and technique. Pressure for quicker operative times, introduction of an 80-hour work week, rising numbers of endovascular procedures replacing open surgery, and the presence of fellowship training programs can limit resident exposure not only to surgical skills, but to attending faculty as well. Our goal was to design a vascular exposures course using fresh frozen cadavers to promote dissection and suturing skills, foster interaction with Vascular Surgery faculty, promote teamwork between residents, and measure the satisfaction of the residents with the course., Methods: A pilot program was created with fresh frozen cadavers used to teach basic vascular surgical anatomy and operating skills to junior and mid-level general surgery residents. The course was organized by the Department of General Surgery and the Division of Vascular Surgery. Trainees completed a general questionnaire and evaluation at the completion of the course., Results: Forty-five general surgery residents participated in 6 independent sessions offered over a 24-month period. Data from 2 questionnaires were entered into a spreadsheet and analyzed. Eighty-five percent of residents found the course met their expectations. Fresh frozen cadaver material was found optimal by all participants. Forty-four of 45 (97.8%) residents rated the educational value of the course with a perfect score and would recommend the course to others., Conclusion: Fresh frozen cadavers provide an excellent opportunity to teach basic open vascular surgery principles while fostering interaction with faculty. Sharing cadavers between multiple disciplines can help with cost containment. more...

Lower extremity revascularization is often described as excessively lesion-centric, with insufficient focus on the patient. We investigated patients' perspectives of multiple procedures for limb salvage that culminated in major lower extremity amputation. A prospective vascular surgery database was queried from January 2000 to December 2005 for patients who had undergone below-knee (BKA) or above-knee (AKA) amputation after failed lower extremity revascularization. Patients were surveyed via telephone by a vascular nurse regarding thoughts on undergoing multiple procedures for limb salvage, involvement in decision making, functional status (work, meal preparation, shopping, driving), use of prosthesis, and independence. The Social Security Death Index was utilized to verify patient survival. Amputations for infection were excluded. Seventy-eight patients underwent AKA or BKA after failed revascularization. Forty-six patients (59%) were alive at 5 years. Thirteen patients were lost to follow-up, leaving 33 available for survey. A total of 142 lower extremity revascularizations (median = 4/patient) were performed on these patients including 94 surgical bypasses (median = 3/patient) and 48 percutaneous interventions (median = 1/patient). Eighty-five percent (28 of 33 patients) of amputees surveyed would do everything to save the leg if faced with a similar scenario, regardless of the number of procedures. Fifty-four percent (18/33) of patients actively used a prosthesis, and 91% (30/33) resided at home. In retrospect, patients are willing to undergo multiple revascularizations--percutaneous or open--to attempt limb salvage even if the eventual result is major amputation. Independence and functional status appear to be obtainable in a majority of patients. Patient-oriented outcomes are necessary to guide revascularization, whether it is by a percutaneous or open technique. more...

We report a case of successful percutaneous fenestration of a chronic aortic dissection for relief of chronic mesenteric ischemia utilizing a transseptal needle to puncture the thickened septum.

Background: Patients with blunt traumatic thoracic aortic transection (BTTAT) just distal to the takeoff of the left subclavian artery typically have concomitant injuries that make open emergent surgical repair highly risky. Over the past decade, endovascular repair of the injured thoracic aorta with commercially available and custom-made covered stents has developed as a viable option, with reported decreases in short-term morbidity and mortality. If active extravasation of contrast from the injured thoracic aorta is not appreciated on chest computed tomography scan, other concurrent injuries of the head, abdomen, and extremities can often be repaired with careful control of blood pressure. The timing of endovascular repair of the traumatic thoracic aortic transection, however, often comes into question, particularly with the presence of fever, pneumonia, or bacteremia. We sought to identify a time frame during which endovascular repair of BTTAT could safely be performed., Methods: Age, concomitant injuries, time from trauma to repair, type of device, and major outcomes were recorded., Results: Over a 5-year period (January 2000 to March 2005), 51 patients presented with BTTAT. Twenty-seven (52.9%) patients with BTTAT died shortly after arrival. Of the remaining 24, 9 underwent emergent open repair, with 1 intraoperative death. Two delayed open repairs were performed. Thirteen patients with BTTAT underwent delayed endovascular repair. Successful endovascular repair of BTTAT was performed in all 13 patients, with no intraoperative deaths. Seven patients were treated with commercial devices and six with custom-made covered stents. None of the repairs was performed emergently. The timing of repair ranged from 1 day to 7 months (median, 6 days), and all patients were treated aggressively with beta-blockade before surgery. One patient was discharged from the hospital and underwent elective repair at a later date. Three patients died in the postoperative period (30 days): two from multisystem organ failure and one from iliac artery complications encountered at the time of device deployment. The remaining 10 patients were successfully discharged to a rehabilitation facility., Conclusions: The opportunity to successfully perform endovascular repair of BTTAT may be possible many days after the initial injury in the hemodynamically stable trauma patient. more...

We report the successful treatment of blunt thoracic aortic trauma with a self-expanding stent lined with commercially available aortic extender cuffs. A 24 x 70 mm Wallstent was positioned distal to the left subclavian artery via a left femoral approach. The stent was then lined with three overlapping Gore Excluder aortic extender cuffs. Intravascular ultrasound was performed pre- and post-deployment. The aortic pseudoaneurysm was successfully excluded. The self-expanding stent facilitated placement of the extender cuffs and improved the contact between the multiple cuffs. This technique could still have utility in emergency settings when approved thoracic endografts are available for this indication. more...

Venous anomalies are not infrequently encountered during aortoiliac reconstruction, because of the complexity of development of the venous system. Retroaortic left renal veins, duplicate inferior vena cava (IVC), and left-sided IVC are occasionally found. Left-sided IVC has been reported with infrarenal aortic aneurysms. We report successful repair of a thoracoabdominal aneurysm in a patient with a left-sided IVC. The embryology and intraoperative management are discussed. more...

Historically, immune-mediated degradation and subsequent aneurysm formation have limited the usefulness of cryopreserved arterial allografts. This study tested the hypothesis that modern cryopreserved arterial allografts are protected from immune-mediated dilation. Abdominal aortas were harvested from anesthetized rats (Lewis and Brown-Norway) for immediate implantation or cryopreservation. Subsequently, Lewis rats underwent infrarenal aortic replacement with either an acutely harvested or a cryopreserved graft. There were four experimental groups: (1) acutely harvested isografts (Iso; n = 6), (2) cryopreserved isografts (C-Iso; n = 6), (3) cryopreserved allografts (C-Allo; n = 6), and (4) acutely harvested allografts (Allo; n = 6). All grafts were explanted at 8 weeks. A video camera and edge detection software were used to measure systolic and diastolic in vivo graft diameter (d). Measurement of arterial blood pressure (p) allowed calculation of compliance (Dd/Dp). Tail-cuff plethysmography was used to assess graft patency at 1 week. Graft diameter and blood pressure measurements were repeated at harvest. All harvested grafts were examined histologically. Our results showed that cryopreservation prevented immune-mediated dilation in arterial allografts in our 8-week rat implant model. Furthermore, the compliance of the cryopreserved grafts and was similar to that of controls. Further investigation is needed to delineate the exact mechanism of these potential clinically significant findings. more...

Purpose: A technique to decrease visceral ischemic time during thoracoabdominal aneurysm (TAA) repair is reported., Methods: A 10 mm Dacron side-arm graft is attached to the aortic prosthesis and positioned immediately distal to the planned proximal thoracic aortic anastomosis. On completion of the anastomosis, a 16 to 22 Fr perfusion catheter is attached to the side-arm graft and inserted into the orifice of the celiac axis or superior mesenteric artery. The cross-clamp is then placed on the aortic graft distal to the mesenteric side-arm graft. Pulsatile arterial perfusion is thus established to the visceral circulation while intercostal anastomoses or reconstruction of celiac, superior mesenteric, and right renal arteries is performed. Visceral ischemic time and the rise in end-tidal Pco2 after reconstruction of the visceral vessels in patients with mesenteric shunting was compared with a control group matched for aneurysm extent and treated immediately before use of the mesenteric shunt technique., Results: Between July and Oct, 1996, the technique was applied in 15 patients undergoing type I, II, or III TAA repair with a clamp and sew technique. The mean decrease in systolic arterial pressure was 12.5 +/- 8.5 mm Hg, with a concomitant rise in end-tidal Pco2 (mean, 6.9 +/- 5.8 mm Hg), after perfusion was established through the mesenteric shunt. Mean time to establishment of visceral perfusion through the shunt was 25.5 +/- 4.4 minutes; the resultant decrement in visceral ischemic time averaged 31.3 minutes (i.e., until celiac, superior mesenteric, and right renal arteries were reconstructed). Compared with controls, patients with shunts had a significantly decreased (6.9 +/- 5.8 versus 21.6 +/- 8.4 mm Hg; p = 0.0003) rise in end-tidal CO2 on completion of visceral vessel reconstruction., Conclusions: In-line mesenteric shunting is a simple method to decrease visceral ischemia during TAA repair, and it is adaptable to clamp and sew or partial bypass and distal perfusion operative techniques. more...

Since the publication of prior reviews on this topic, substantial clinical experience with a variety of operative strategies to prevent ischaemic cord complications has been reported. The available data on angiographic localisation of critical intercostal vessels, and, in particular, the evoked potential response to cross-clamping in patients indicates that risk of paraplegia varies considerably even among patients with equivalent TAA extent. Factors such as individual development of the ASA, patent critical intercostals, and the particulars of collateral circulation when intercostal aortic ostia are already occluded likely account for this variability. Information available from SSEP monitoring relative to the dynamic course of cord ischaemia with cross-clamping, and the parallel, if not, frustrating experience with angiographic localisation and intercostal vessel reconstruction indicates that a narrow temporal threshold of cord ischaemia with clamping is present in many patients. This reinforces the importance of both expeditious clamp intervals, critical intercostal re-anastomoses, and the desirability of neuroprotective manoeuvres during cross-clamp induced cord ischemia. As suggested in compelling experimental work our contemporary clinical experience, and predicted by prior reviewers, regional cord hypothermia provides significant promise for limiting or eliminating, in particular, immediate perioperative deficits. Avoidance of postoperative hypotension, spinal cord oedema, and preservation of critical intercostal vessels are additional strategies necessary to impact the development of delayed deficits favourably. more...

Background: Delayed-onset reflex increases in mean arterial pressure (MAP) occur during clamping of the infrarenal aorta. This study investigated the afferent limb of the reflex by independently altering femoral artery blood pressure (FBP) or fractional concentration of inspired oxygen (FIO2) while monitoring systemic arterial blood pressure., Methods: The infrarenal aorta was divided, and an occlusive roller pump delivered incremental flow to the distal aorta thus controlling FBP. In six dogs the FBP was reduced in random order to 50, 40, 30, 20, and 10 mm Hg and held constant for 30 minutes. In another six dogs the FBP was held at 20 mm Hg, whereas the FIO2 was randomly varied among 0.13, 0.21, and 1.0 for 30-minute intervals., Results: Under these conditions MAP was significantly and inversely correlated with FBP (MAP was 172 +/- 8 mm Hg when FBP was 10 mm Hg, p < 0.0001; MAP was 158 +/- 8 mm Hg when FBP was 20 mm Hg, p = 0.0001; MAP was 138 +/- 7 mm Hg when FBP was 30 mm Hg, p = 0.0048; and MAP was 130 +/- 7 mm Hg when FBP was 40 mm Hg, p = 0.0045). MAP was significantly and inversely related to the FIO2 value when FBP was fixed at 20 mm Hg (MAP of 186 +/- 9 mm Hg at FIO2 of 0.13 and was significantly higher than MAP of 163 +/- 11 mm Hg at FIO2 of 0.21, p = 0.01; and MAP of 157 +/- 10 mm Hg at FIO2 of 1.0, p = 0.0001)., Conclusions: The magnitude of the delayed systemic pressor response is inversely proportional to the FBP. We suggest that this pressor response is also particularly sensitive, in part, to arterial blood oxygen tension when hindlimb perfusion pressure is low. more...

Aortic clamp-induced hypertension has long been implicated in the cardiovascular mortality and morbidity following infrarenal aortic operations. We studied the physiologic mechanisms leading to clamp-induced hypertension. Mean arterial pressure (MAP), cardiac output, heart rate, and left ventricular pressure were measured in alpha-chloralose-anesthetized dogs. Animals received alpha, beta, both alpha and beta, or no adrenergic blockade (n = 3, 4, 12 and 7, respectively). The infrarenal aorta was clamped following ligation of the infrarenal collateral vessels (lumbar, circumflex iliac, and tail arteries). Statistical analysis used paired t tests within groups, and ANOVA and unpaired t tests between groups, with Bonferroni's correction as indicated. Following placement of the clamp, MAP increased immediately in all groups, with magnitude of the increase related to the extent of adrenergic blockade. MAP increased 5.6 +/- 0.8 mm Hg with no blockade (P = 0.0005), 6.7 +/- 0.8 mm Hg with alpha blockade (P = 0.0153), 15 +/- 3.1 mm Hg with beta blockade (P = 0.0163), and 16.7 +/- 1.3 mm Hg with combined alpha and beta blockade (P < 0.0001). The increase in MAP immediately following infrarenal aortic clamping was most pronounced with combined alpha and beta blockade. We suggest that acute intraoperative hypertension associated with infrarenal aortic clamping is caused by the attenuation of compensatory baroreceptor reflex mechanisms. more...

Purpose: Unexplained anatomic and physiologic factors account for the unacceptably high rate of paraplegia/paresis after thoracoabdominal aortic reconstruction. We assessed the neurologic significance of patent internal mammary arteries (IMAs) in a novel rat model of aortic clamping in which the aortic origins of the intercostal arteries (ICAs) were occluded., Methods: Twenty anesthetized, intubated, and halothane-ventilated adult male rats had catheters placed in the carotid and femoral arteries. ICAs arising from the aorta were divided at their origins through a left thoracotomy. IMAs were either divided (IMA-OUT, n = 10) or left intact (IMA-IN, n = 10). Proximal and distal descending aortic clamps were placed for 7 minutes. A neurologic deficit score (NDS) was assigned at 1, 4, 18, 24, and 48 hours by use of an established scoring system., Results: The mean IMA-IN NDS was statistically better than the mean IMA-OUT NDS at 1, 4, 18, and 24 hours with p = 0.0005, 0.0014, 0.0098, and 0.0151, respectively. Moreover, the mortality rate in the IMA-OUT group was statistically greater than in the IMA-IN group (p = 0.0036)., Conclusion: In this model, patent IMAs prevent paraplegia when the ICAs are occluded at their aortic origin and the aorta is clamped for 7 minutes. more...

A number of different biological properties have been ascribed to the hormone-like protein interleukin 2 (IL-2). However, the most salient feature of this lymphokine is its ability to sustain the long-term proliferation of T-cells from humans and mice. Reported herein are the results of studies demonstrating the isolation of growth factor-independent cell lines from the long-term IL-2-dependent murine T-cell line CTLL-2 that is used frequently as the source of target cells in IL-2 bioassays. Sustained log-phase growth of these T-cells in vitro has been achieved using Petri dishes of polymethylpentene; growth could not be sustained in similar dishes of glass, untreated polystyrene, polystyrene that had been treated for cell culture, or polycarbonate. The IL-2-independent line grew as a T-cell lymphoma when injected i.p. into pristane-treated, but not untreated, syngeneic C57BL/6 mice. In contrast, cells from the IL-2 parental line CTLL-2 did not grow in vivo. Characterization of the IL-2-independent lines propagated in vitro (denoted as line CEC) or in vivo (denoted as line CEP) demonstrated that they retained their dependency for 2-mercaptoethanol and expressed phenotypic profiles of their parental line CTLL-2 (Thy 1.2+, Lyt-1-; Lyt-2-). Isolation of an IL-2-independent T-cell lymphoma from a CTLL-2 line obtained from another investigator using a protocol that has proven reproducible under carefully controlled laboratory conditions and defined phenotypic traits of the syngeneic T-cell isolates provided evidence that the tumors were not a cross-culture contaminant arising as a result of a laboratory accident. Moreover, karyotypic analysis using a quinacrine:Hoechst banding technique revealed similar marker chromosomes in the IL-2-dependent and -independent lines. IL-2-independent lines have also been established from the IL-2-dependent murine T-cell line CT-6. Accordingly, the results of these studies suggest that, during prolonged cultivation that has included exposure to crude IL-2 preparations known to contain phorbol ester, possibly viruses, and other contaminants, the IL-2-dependent lines have developed subpopulations that are thought to have undergone malignant transformation of unknown etiology to generate IL-2-independent murine T-cell lymphomas that can be passaged repetitively either in vitro or in vivo. more...