EphB4 receptor tyrosine kinase is expressed in bladder cancer and provides signals for cell survival.

We sought to evaluate the biological function of the receptor tyrosine kinase EphB4 in bladder cancer. All of the nine bladder cancer cell lines examined express EphB4 and the receptor could be phosphorylated following stimulation with its cognate ligand, EphrinB2. Out of the 15 fresh bladder cancer specimens examined, 14 expressed EphB4 with a mean sevenfold higher level of expression compared to adjacent normal urothelium. EphB4 expression was regulated by several mechanisms: EPHB4 gene locus was amplified in 27% tumor specimens and 33% cell lines studied; inhibition of EGFR signaling downregulated EphB4 levels; and forced expression of wild-type p53 reduced EphB4 expression. EphB4 knockdown using specific siRNA and antisense oligodeoxynucleotides molecules led to a profound inhibition in cell viability associated with apoptosis via activation of caspase-8 pathway and downregulation of antiapoptotic factor, bcl-xl. Furthermore, EphB4 knockdown significantly inhibited tumor cell migration and invasion. EphB4 knockdown in an in vivo murine tumor xenograft model led to a nearly 80% reduction in tumor volume associated with reduced tumor proliferation, increased apoptosis and reduced tumor microvasculature. EphB4 is thus a potential candidate as a predictor of disease outcome in bladder cancer and as target for novel therapy.

Angiotensin II increases glucose utilization during acute hyperinsulinemia via a hemodynamic mechanism.

To determine whether hemodynamic changes can modulate insulin action in vivo, we administered angiotensin II (AII) to normal men under three separate, euglycemic conditions. First, in the presence of physiological hyperinsulinemia (approximately 115 microU/ml), infusion of AII at rates of 2, 10, and 20 ng/min per kg caused significant elevations of blood pressure, whole-body glucose clearance, and plasma insulin concentrations in an AII dose-dependent manner. Second, in the presence of plasma insulin concentrations that stimulate glucose transport maximally (approximately 5,000 microU/ml), AII infusions increased whole-body glucose clearance without enhancing glucose extraction across the leg. Third, in the presence of basal insulin concentrations (approximately 13 microU/ml), AII infusions had no effect on whole-body glucose turnover or leg glucose extraction. Thus, AII enhanced whole-body glucose utilization without directly stimulating glucose transport in a major skeletal muscle bed. To evaluate a possible hemodynamic mechanism for the effects of AII on glucose utilization, we measured blood flow to two areas that differ in their sensitivity to insulin: the kidneys and the leg. We found that AII redistributed blood flow away from the predominantly insulin-independent tissues of the kidney and toward the insulin-sensitive tissues of the leg during both sham and hyperinsulinemic glucose clamps. The redistribution of flow had no effect on whole-body glucose turnover when leg glucose uptake was unstimulated (sham clamps). However, when leg glucose uptake was activated by insulin, the redistribution of flow caused a net increase in whole-body glucose utilization. Our findings indicate that hemodynamic factors can modulate insulin action in vivo. Furthermore, our results suggest that variable activity of the renin-angiotensin system may contribute to inconsistencies in the association between insulin resistance and hypertension.

Penetrating trauma of the internal carotid artery.

OBJECTIVE: To assess management of penetrating internal carotid artery (ICA) injuries. DESIGN: Retrospective review of institutional protocol. SETTING: Level 1 trauma center in a major urban area. PATIENTS: Sixty-one patients with penetrating ICA injuries. INTERVENTIONS: In the period 1975 to 1987 (group 1; n = 36), management was based on individual surgeons' preferences. Between 1988 and 1995 (group 2; n = 25), an algorithm was employed: (1) hemodynamically stable patients with suspected ICA injuries underwent a diagnostic angiography; (2) surgically accessible injuries were reconstructed regardless of neurologic status with 2 exceptions: (a) neurologically intact patients with ICA occlusion were treated by anticoagulation and mild pharmacological hypertension and (b) minimal nonocclusive injuries were managed nonoperatively and followed up by serial angiography or duplex ultrasonography; and (3) heparinization, shunting, and completion angiography were employed. MAIN OUTCOME MEASURES: Neurologic status at admission and discharge were compared by the Fisher exact test. RESULTS: In group 1, 24 patients (67%) presented neurologically intact, and 12 (33%) with a deficit. Sixteen injuries were managed nonoperatively, 14 were repaired, and 6 were ligated. At discharge 6 (17%) were improved, 24 (66%) were unchanged, 6 (17%) were worse. Four patients (11%) died of cerebrovascular causes. In group 2, 19 patients (76%) presented neurologically intact, and 6 (24%) with a deficit. Eleven injuries were managed nonoperatively, 12 were repaired, and 2 were ligated. A death occurred in a patient who arrested, was admitted to the hospital in a coma, and died before ICA repair. CONCLUSIONS: Neurologic outcome after ICA injury is enhanced by an algorithm predicated on the liberal use of angiography, a predefined surgical approach, and selective observation.

Selective management of nonocclusive arterial injuries.

Between 1978 and 1988, 50 patients were demonstrated arteriographically to have 61 nonocclusive arterial injuries (44 major arteries, 17 minor arteries). The 61 injuries consisted of 19 intimal defects, 4 intimal flaps, 26 pseudoaneurysms, 2 arterial stenoses, and 10 arteriovenous fistulas. End-organ ischemia or ongoing hemorrhage were not present. All patients were treated nonoperatively. At 1 to 12 weeks after the injury, 30 arterial injuries (24 major, 6 minor) were studied by repeated arteriography. Resolution, improvement, or stabilization of the injury occurred in 21 (87%) major artery injuries. Progression occurred in the remaining 3 injuries, including 1 patient who underwent subsequent successful repair. Twenty-one injuries were followed up without repeated arteriography. Delayed arterial thrombosis, hemorrhage, or ischemia did not develop, and no patient required operative management. Eight of 10 additional arterial injuries had successful percutaneous embolization at the time of repeated arteriography. The overwhelming majority of small arterial injuries or intimal fractures do not lead to vascular complications if managed nonoperatively. A routine policy of operative exploration for all such injuries is therefore unwarranted. These injuries are best managed by observation and serial arteriography to document spontaneous healing or progression.

A prospective study of carbon dioxide-digital subtraction vs standard contrast arteriography in the evaluation of the renal arteries.

OBJECTIVE: To compare carbon dioxide-digital subtraction arteriographic (CO2-DSA) images of renal artery anatomy with standard iodinated contrast arteriographic (ICA) images. DESIGN: One hundred patients with vascular disease who required abdominal aortography were evaluated by both CO2-DSA and ICA modalities. Two blinded readers interpreted arteriograms for the degree of renal artery stenosis, and a third reader was employed to resolve differences in reader interpretations. SETTING: University medical center. MAIN OUTCOME MEASURES: The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy were calculated for the ability of CO2-DSA to demonstrate a 60% or greater stenosis of the main renal artery; kappa values for CO2-DSA and ICA were calculated to assess intraobserver variability. RESULTS: Of the 200 main renal arteries imaged, 17 (9 by means of CO2-DSA), 8 means of ICA) were eliminated because of inadequate visualization of the renal artery. In identifying a renal artery stenosis of 60% or greater, CO2-DSA had a sensitivity of 0.83, specificity of 0.99, positive predictive value of 0.94, and negative predictive value of 0.98. The overall accuracy was 0.97. The kappa was 0.75 for CO2-DSA and 0.70 for ICA, hence, the variation in the interpretations of CO2-DSA and ICA were comparable. CONCLUSION: Images by means of CO2-DSA accurately reflect pathologic changes in renal arteries and are thus useful in the diagnosis of clinically occult occlusive renal artery disease in patients at risk of contrast medium-related nephrotoxicity.

The role of arterial reconstruction in penetrating carotid injuries.

The outcome of 80 patients with 85 penetrating injuries to the extracranial carotid artery (CA) were analyzed after three types of treatment: (1) 54 patients, 17 with a neurologic deficit, who underwent arterial reconstruction; (2) 18 patients, eight with a neurologic deficit, who had CA ligation or non-operative management of a CA occlusion; and (3) eight patients, two with a deficit, who had minimal nonocclusive injuries managed nonoperatively. Outcome was analyzed using a Carotid Neurologic Score (CNS). The CNS is a quantitative measure of neurologic outcome and survival and ranges from -1 to +3. The higher the CNS, the more favorable the outcome. The conditions of nine patients in group 1 neurologically improved after treatment, 41 were the same, and four were worse. Forty-four patients were neurologically intact and three died. The mean (+/- SD) CNS was 1.9 +/- 0.8. In group 2, one patient's condition improved, 13 stayed the same, and four deteriorated. Ten patients were intact and two died. The mean CNS was 1.3 +/- 1.13. In group 3, two patients' conditions improved and six stayed the same. All eight patients were intact; there were no deaths. The mean CNS was 2.3 +/- 0.35. There was a significantly higher CNS for groups 1 and 3 compared with group 2. The CNSs of groups 1 and 3 were not significantly different. Arterial reconstruction provides the best outcome for all penetrating CA injuries except nonocclusive limited intimal injuries that require only observation.

Examination of the patient with a knee dislocation. The case for selective arteriography.

One hundred fifteen patients with a unilateral knee dislocation underwent arteriography to examine the popliteal artery. The incidence of popliteal artery injury was 23% (27 patients). Clinically, 29 (25%) of the 115 patients had an abnormal ipsilateral pedal pulse and 23 (79%) of these 29 patients had an arteriographically identified popliteal artery injury. Twenty-two arteries were surgically repaired and one was treated without surgery. Eight-six patients had normal pulses; the arteriogram showed no abnormalities in 77, demonstrated spasm in five, and revealed an intimal flap in four. All 86 patients were treated without surgery and had no delayed vascular complications. This demonstrates that the vascular examination is an accurate predictor of major popliteal artery injury following knee dislocation. Patients with an abnormal pedal pulse warrant arteriography due to a high incidence (79%) of popliteal artery injury. Patients with normal pulses may be monitored by clinical examination only. Popliteal artery injuries in this group are minor and rarely require intervention.

Is arterial proximity a valid indication for arteriography in penetrating extremity trauma? A prospective analysis.

Three hundred seventy-three patients with a penetrating extremity injury were studied to assess the yield of arteriography. Patients underwent arteriography if any of the following was present: bruit, history of hemorrhage or hypotension, fracture, hematoma, decreased capillary refill, major soft-tissue injury, or nerve or pulse deficit. In the absence of these findings, arteriography was performed if the injury was in "proximity" to a major neurovascular bundle. In 216 patients, arteriography was performed when an abnormal finding was noted. Sixty-five injuries were identified, 19 requiring intervention. Proximity was the indication for arteriography in 157 patients. Seventeen injuries were identified, of which one required repair. In penetrating extremity trauma, the need for arteriography is based on clinical findings. The use of arteriography to screen for an arterial injury when proximity alone is the indication rarely identifies a significant injury and should be abandoned.

Technique of radical cystectomy and simultaneous repair of an abdominal aortic aneurysm.

Surgical repair of an abdominal aortic aneurysm in conjunction with radical cystectomy and orthotopic urinary diversion can be safely performed without morbidity secondary to excessive blood loss, operative time, or vascular graft infection. The techniques required for this combined procedure and a case report are discussed.

Retroviral vector-mediated transfer and expression of human tissue plasminogen activator cDNA in bovine brain endothelial cells.

OBJECTIVES: Gene transfer of thrombolytic enzymes to vascular endothelial cells may influence the kinetics of intravascular thrombosis. This study defines the potential for gene transfer of tissue plasminogen activator (tPA) into bovine brain endothelial cells (BBEC). METHODS: The retroviral vectors derived from murine leukemia virus (MuLV) were used to transfer human tPA cDNA to BBEC. The tPA activity, tPA antigen and tPA inhibitor 1 (PAI-1) antigen were determined in the supernatant of transduced (BBEC/tPA) cell cultures by an immunoassay. RESULTS: The tPA antigen and enzymatic activity in cell culture supernatants of BBEC/tPA transduced cells were 75 ng/ml and 14 IU/ml after 4 days, that was 25 and 28-fold higher compared to the respective values in control cells. The PAI-1 antigen was not affected by tPA cDNA transfer. The Western blot assay of cell lysates confirmed that the majority of tPA in BBEC/tPA transduced cells was in the form of free tPA. While the maximal transduction efficiency of BBEC with an amphotropic MuLV vector was about 15%, a MuLV pseudotyped with vesicular stomatitis virus G glycoprotein envelope achieved high > 90% maximal transduction efficiency. CONCLUSIONS: The fibrinolytic activity of brain endothelial cells can be enhanced by transferring human tPA cDNA. These findings provide an initial step in implementation of future studies that investigate the use of this technology as an adjunctive treatment for cerebrovascular disease.

Advances in the treatment of phlegmasia cerulea dolens.

Phlegmasia cerulea dolens (PCD) is an uncommon, severe form of lower extremity deep venous thrombosis characterized by extremity swelling, cyanosis, and pain. Progression of the thrombotic process may result in extremity gangrene, amputation, and death. The relative value of specific therapeutic regimens in the treatment of this disease remains uncertain. Twelve patients, 9 females and 3 males, with PCD were treated during a 10-year period. Eighteen lower extremities were involved. Pre-existing conditions included malignancy (eight), postoperative state (four), diabetes (three), previous deep venous thrombosis (three), and hypercoagulation (two). Venous gangrene was present in four patients. All patients were treated initially with bedrest, fluid resuscitation, extremity elevation, and systemic high-dose heparin therapy. Five patients had complete resolution with this regimen alone. One patient required cessation of heparin therapy due to heparin-induced thrombocytopenia and developed gangrenous toes. Two patients whose condition failed to respond to heparin therapy underwent catheter-based delivery of urokinase with marked clinical improvement. Four patients, two with venous gangrene, died, three of whom had disseminated malignant disease. A significant percentage of patients with PCD will respond to extremity elevation, fluid resuscitation, and aggressive systemic anticoagulation therapy. Thrombolytic therapy selectively administered is beneficial in patients whose disease fails to respond promptly. Venous thrombectomy should be reserved for patients with contraindications to thrombolysis.

Clinical results of decompressive dermotomy-fasciotomy.

Seventy-three dermotomy-fasciotomies (DFs) were performed in 68 patients from 1986 to 1991. A database record was compiled on each patient. Variables included age, mode of injury, method of initial wound closure, and associated injuries. A multivariate stepwise logistic regression analysis was performed to determine which variables were associated with wound complications. Thirty-eight percent of patients who underwent DF developed wound complications. One hundred percent of those patients with postoperative arterial or graft thrombosis developed wound complications (p less than 0.01) as did 78% of those with thromboembolic disease (p less than 0.05). Conversely, only 5% of those who underwent closure of their DF wounds utilizing skin grafts developed wound complications (p less than 0.01) as compared with 51% of those who underwent secondary or primary closure only. Subsequent analysis of the remaining patients, excluding those with severe soft tissue injury, showed an association between location of DF (upper versus lower extremity) and the development of wound complications that approached statistical significance (p less than 0.06). DF is frequently necessary in the treatment of patients with compartment syndrome but is associated with significant morbidity. This study suggests that closure of DF wounds utilizing skin graft allows for continued osteofascial decompression while concomitantly minimizing invasive sepsis.

Role of routine arteriography in blunt lower-extremity trauma.

During an 18-month period, 53 patients with unilateral blunt lower-extremity trauma were entered into a prospective study designed to determine how often clinically occult arterial injuries are identified by routine arteriography, and how often these injuries are of sufficient magnitude to warrant therapeutic intervention. Patients underwent diagnostic arteriography if one or more of the following abnormal clinical findings were present: distal pulse deficit, nerve deficit, soft-tissue loss, decreased capillary refill, bruit, or a history of hemorrhage or hypotension. In the absence of these findings, arteriography was performed for significant orthopedic injuries, i.e., knee dislocations or complex long-bone fractures. In 31 patients (58%), arteriography was performed because 1 or more abnormal clinical findings were present and 12 arterial injuries were identified, 4 requiring arterial repair. The presence of a knee dislocation or complex long-bone fracture was the only indication for arteriography in 22 patients (42%) and 3 arterial injuries were identified, none requiring operative intervention. For all patients, two variables, pulse deficit and delayed capillary refill, strongly correlated (p less than 0.05) with arteriographic demonstration of an arterial injury. In the absence of these findings, routine diagnostic arteriography will have a low diagnostic yield and will rarely identify a vascular injury in a major artery that will require operative repair. Arteriography should be selectively performed and guided by examination and noninvasive Doppler indices.

Trends in the management of traumatic vertebral artery injuries.

From 1975 to 1988, 25 patients with a vertebral artery (VA) injury were treated. Admission neurologic status was intact in 14 patients (56 percent). Eight patients had deficits due to direct nerve or spinal cord injury, two patients had symptoms referable to vertebrobasilar ischemia, and one patient had a contralateral deficit due to an associated carotid artery injury. Twenty-two of 25 patients (88 percent) underwent diagnostic arteriography. Twelve patients (48 percent) with 9 occlusive and 3 minimal injuries were observed. Seven patients (28 percent), three with exsanguinating hemorrhage, were treated by operative exploration and VA ligation. Six patients (24 percent), two with a VA pseudoaneurysm and four with an arteriovenous fistula, were managed by percutaneous transcatheter embolization. The neurologic status was unchanged or improved in 22 patients (88 percent) at discharge. Two patients developed Horner's syndrome after VA ligation. Transient posterior circulation ischemia occurred in a single patient after percutaneous transcatheter embolization. There was no mortality. The majority of VA injuries are best managed by nonoperative methods. Untoward neurologic sequelae are rare. Operative intervention and VA ligation should be reserved for patients with active hemorrhage or large pseudoaneurysms and arteriovenous fistulas which cannot be embolized.

Results of a prospective, randomized trial of surgery versus thrombolysis for occluded lower extremity bypass grafts.

PURPOSE: The purpose of this study was to prospectively evaluate the treatment of patients with occluded lower extremity bypass grafts, comparing surgical revascularization with catheter-directed thrombolysis. MATERIALS AND METHODS: One hundred twenty-four patients (68% male and 32% female) with lower limb bypass graft occlusion (46 autogenous and 78 prosthetic) were prospectively randomized to surgery (n = 46) or intra-arterial catheter-directed thrombolysis (n = 78) with recombinant tissue plasminogen activator (rt-PA) 0.1 mg/kg/h modified to 0.05 mg/kg/h for up to 12 hours, or urokinase (UK) 250,000 U bolus followed by 4,000 U/min for 4 hours, then 2,000 U/min for up to 36 hours. A composite clinical outcome including death, amputation, ongoing/recurrent ischemia, and major morbidity was analyzed on an intent-to-treat basis at 30 days and 1 year. RESULTS: The average duration of graft occlusion was 34.0 days, with 58 (48%) presenting with acute ischemia (0 to 14 days) and 64 (52%) with chronic ischemia (> 14 days). Thirty-nine percent randomized to lysis failed catheter placement and required surgical revascularization. Overall, there was a better composite clinical outcome at 30 days (P = 0.023) and 1 year (P = 0.04) in the surgical group compared with lysis, due predominately to a reduction in ongoing/recurrent ischemia, most notable in autogenous grafts. However, following successful catheter placement, patency was restored by lysis in 84%, and 42% had a major reduction in their planned operation. One-year results of successful lysis compared favorably with the best surgical procedure, which was new graft placement. Acutely ischemic patients (0 to 14 days) randomized to lysis demonstrated a trend toward a lower major amputation rate at 30 days (P = 0.074) and significantly at 1 year (P = 0.026) compared with surgical patients, while those with > 14 days ischemia showed no difference in limb salvage but higher ongoing/recurrent ischemia in lytic patients (P < 0.001). Patients with occluded prosthetic grafts had greater major morbidity than did those with occluded autogenous grafts (P < 0.02). CONCLUSIONS: Proper catheter positioning currently limits the potential of catheter-directed thrombolysis for lower extremity bypass graft occlusion. Patients with graft occlusion > 14 days have a significantly better outcome when treated surgically, with a new bypass being the best surgical option. However, in patients with acute limb ischemia (< 14 days) successful thrombolysis of occluded lower extremity bypass grafts improves limb salvage and reduces the magnitude of the planned surgical procedure. Patients with occluded prosthetic grafts suffer more major morbid events compared with occluded autogenous grafts.

Difficult peripheral vascular injuries.

Successful management of the difficult peripheral vascular injury requires a multidisciplinary approach. Prompt recognition of the vascular injury and adherence to the recognized principles of vascular repair provide a successful short-term surgical result. The long-term consequences of an injury are determined by the associated orthopedic, soft tissue, and nerve injuries.

Cervical vascular injuries: carotid and jugular venous injuries.

This article explores the management of carotid arterial injuries, detailing the historical evolution for the management of these injuries and delineating techniques for cerebral perfusion and preservation with shunts. It discusses the role of autogenous versus synthetic grafts in the management of these injuries and the issue of vascular complications and potential pitfalls. Jugular venous injuries are addressed also, with emphasis on the controversies of primary repair versus ligation.

Tissue culture cytotoxicity assay for cyclophosphamide metabolites in rat body fluids.

An in vitro cytotoxicity assay for cyclophosphamide metabolites in rat body fluids is described. Of the two tissue culture tumor cell lines employed, the Walker-256 rat carcinosarcoma was more sensitive to metabolite levels than the L-1210 mouse lymphocytic leukemia. The Walker-256 system detected cyclophosphamide metabolite levels two orders of magnitude lower than the commonly used 4-(p-nitrobenzyl)pyridine analytical procedure.

Magnetic resonance imaging of a post-traumatic arteriovenous fistula in the lower extremity.

Currently, magnetic resonance (MR) is most useful as a means of providing distinct images of gross abnormalities in major blood vessels. While new advances and further refinements will continue, MR has proven its value as a convenient and effective diagnostic tool for the recognition and delineation of vascular abnormalities, such as acquired arteriovenous fistulae (AVFs). We report a case of a chronic, post-traumatic AVF, in which MR angiography provided excellent anatomic detail and angiographic correlation.

The practical implications of recent trials comparing thrombolytic therapy with surgery for lower extremity ischemia.

UNLABELLED: Catheter-based thrombolysis for lower extremity ischemia is a well-accepted and frequently used technique. Three prospective randomized trials, Rochester, STILE, and TOPAS, which compared thrombolytic therapy with traditional surgical revascularization for lower limb ischemia, have recently been published. METHODS: These three trials are reviewed with the intent of assessing the relative of value of thrombolytic therapy and surgical revascularization for lower limb ischemia. RESULTS: As an initial therapy, thrombolysis reduces the magnitude of any subsequent surgical procedure in approximately 40% to 60% of patients. However, recurrent ischemia is frequent, and the subsequent need for surgical revascularization is common for any native artery occlusion or chronic (> 14 days) bypass graft occlusion. In the patient with an acute bypass graft occlusion, the incidence of recurrent ischemia is less and limb salvage at 1 year is enhanced when treated initially by thrombolysis. A possible survival benefit after thrombolysis was suggested in the Rochester trial and in the STILE trial for diabetics with femoral-popliteal occlusions. CONCLUSIONS: Surgical revascularization remains the optimal therapy for most patients with lower limb ischemia. However, thrombolysis as an initial therapy does reduce the magnitude of any subsequent surgical procedure and provides improved limb salvage for patients with acute bypass graft occlusions.