Effects of organic matter on the distribution of uranium in soil and plant matrices.

This work studied interactions of uranium with pure organic compounds, such as glutathione, and more complex mixtures, such as humic acid and aqueous plant extracts. High performance liquid chromatography with UV absorption interfaced to inductively coupled plasma mass spectrometry sequential detection was used to detect organouranium complexes in a variety of soils and plant materials, indicating that nearly 100% of the uranium extracted from certain plant tissues was bound to organic ligands. In addition, soil sorption experiments indicated that humic acid generally decreased uranium sorption to soils and promoted subsequent desorption of uranium because of uranium partitioning to the organic phase. These experiments demonstrate that organic compounds influence the mobility and chemistry of uranium in the environment.

First Report of Sclerotinia sclerotiorum Infection on Cuphea.

Species of the genus Cuphea (family Lythraceae) are being developed as potential domestic sources of medium length fatty acids (lauric and capric) for use in industrial lubricants and detergents. During September 2004, patches of dead plants were observed in test plots of Cuphea sp. cv. PSR-23 (1) (Cuphea viscosissima Jacq. × C. lanceolata W.T. Aiton) near Morris, MN and Prosper, ND, approximately 200 km apart. Seed yield in the diseased Morris field was 78 kg/ha compared with 516 kg/ha in nearby, nonaffected fields of the same variety, for an 85% yield reduction. Stems were split open to reveal long, cylindrical sclerotia as much as 8 mm long. Isolations from diseased stem tissue and sclerotia were identified as Sclerotinia sclerotiorum (Lib.) de Bary and produced typical sized sclerotia (4 to 6 mm in diameter) after 7 days growth on potato dextrose agar (PDA). Cuphea PSR-23 plants were grown in the greenhouse in individual pots for 5 weeks and then inoculated. Three inoculation methods were used. For the first method, ascospores of a sunflower isolate of S. sclerotiorum were sprayed onto blooming flowers and foliage at a rate of 5,000 spores per ml. The inoculated plants were kept in a dark, 18°C mist chamber for 48 h and then returned to a greenhouse maintained at 24/20°C, day/night temperatures. All 20 inoculated plants were visibly colonized by Sclerotinia sp. after 3 days, and all plants were dead by 7 days. The second inoculation used the petiole inoculation technique employed by canola researchers (2). The blade from the third leaf was excised and a micropipette tip containing an agar disk of mycelia of the Cuphea isolate was placed over the cut end of the petiole. Five days after inoculation, all 30 inoculated plants were dead, while none of the 10 control plants (using sterile agar disks on the cut petiole) were affected. Isolations were made from diseased plants inoculated by all methods, and S. sclerotiorum colonies were observed on PDA medium with typical sclerotia from 4 to 6 mm in diameter. The third inoculation method tested root infection. S. sclerotiorum was grown on autoclaved proso millet (Panicum miliaceum L.) seed for 7 days, and 5 g of colonized millet seed was placed in a hole 6 cm from the base of a Cuphea plant, with one plant per 3.7 liter pot. Sunflower (Helianthus annuus L.; oilseed hybrid Cargill 270) plants served as inoculated controls. None of the 20 Cuphea plants were infected via soil inoculations compared with 70% of 30 sunflower plants that developed basal stalk rot and wilt within 2 weeks after inoculation. To our knowledge, this is the first report of S. sclerotiorum infection on Cuphea sp., and is believed to be the first report of infection on any genus within the Lythraceae (loosestrife family). With over 100 annual and perennial species in the genus Cuphea, the possibility of Sclerotinia spp. resistance needs to be investigated to further develop this potential oilseed crop. References: (1) S. J. Knapp and J. M. Crane. Crop Sci. 40:299, 2000. (2) J. Zhao et al. Plant Dis. 88:1033, 2004.

First Report of Soft Rot Caused by Sclerotinia sclerotiorum on Borage in North Dakota.

Borage (Borago officinalis) is an oilseed crop that is being evaluated as an alternative crop in North Dakota. During September 2004, borage plants in a field in Cass County, North Dakota were dying from a watery soft rot. The main stems and lateral branches were affected, and affected plants were usually completely lodged and prostrate. Dead plants had bleached and shredded stems with black sclerotia (9.1 ± 3.0 × 2.6 ± 0.5 mm) inside the pith and on the epidermis. At the time of observation, borage plants were flowering and forming pods and seed. Approximately 60% of the plants were visually affected by the watery soft rot. Sclerotia were collected from diseased plants, soaked in a 0.5% NaOCL solution for 30 s, air dried, and placed in petri dishes containing potato dextrose agar (PDA). A fungus grew from the plated sclerotia that subsequently produced white mycelium and black sclerotia (4.8 ± 1.2 × 2.5 ± 1.0 mm), which is characteristic of Sclerotinia sclerotiorum (Lib.) de Bary (3). To confirm pathogenicity, borage plants were inoculated in the greenhouse with a S. sclerotiorum isolate from field-infected borage. Thirteen borage plants were grown from seed in the greenhouse under natural sunlight at a temperature range of 24 ± 3°C. When plants were at the four-leaf stage (approximately 16 cm high), the second leaf was excised from each plant with the petiole remaining on the plant. The leafless petioles were inoculated using a method previously described (2). Petioles of 10 plants were inoculated with PDA containing mycelium of the S. sclerotiorum borage isolate, while petioles of five plants were inoculated with PDA to serve as a control. Three days after inoculation, plants inoculated with the S. sclerotiorum borage isolate were beginning to wilt and 5 days after inoculation, these plants were completely wilted and prostrate, similar to observations made on field-infected plants. Sclerotia collected from the diseased, inoculated plants were placed on PDA, and S. sclerotiorum was successfully recovered. Control plants inoculated with PDA did not show any disease symptoms. Other plant genera in the Boraginaceae are known hosts of S. sclerotiorum (1); however, to our knowledge, this is the first report of borage as a host. References: (1) G. J. Boland and R. Hall, Can. J. Plant Pathol. 16:93, 1994. (2) L. E. del Río et al. (Abstr.) Phytopathology 90(suppl.):S176, 2000. (3) D. L. Tourneau, Phytopathology 69:887, 1979.

First Report of White Mold Caused by Sclerotinia sclerotiorum on Echium (Echium vulgare).

Echium, also known as common viper's bugloss, is a member of the botanical family Boraginaceae. Echium is being evaluated for its potential use as an oilseed crop in North Dakota. In 2003, 40% of echium plants in a field in Cass County were observed showing classical symptoms of infection by Sclerotinia sclerotiorum. Plants in advanced stages of infection were dead. Stems of dead plants peeled off easily when touched and numerous cylindrical, black sclerotia that were 2 to 3 mm in diameter and 4 to 7 mm long were found in the pith. Younger stem lesions were watery soft, many of them with a white cottony growth on them. Sclerotia and infected stem tissues collected from the field were surface disinfested in a 0.5% NaOCl solution for 30 s, rinsed with sterile distilled water, and air dried before plating on potato dextrose agar (PDA). Samples were incubated at room temperature for 1 week. White mycelium and black sclerotia, characteristic of S. sclerotiorum (Lib.) de Bary, were produced in all dishes. Koch's postulates were fulfilled using the petiole inoculation technique (2). Briefly, 4-mm agar plugs containing hyphal tips of a 2-day-old S. sclerotiorum colony growing on PDA were excised and loaded in the wide opening of 100-µl pipette tips. The second true leaf of 15 3-week-old echium seedlings, growing in plastic pots containing Ready-Mix soil, was cut off with a razor blade leaving an approximately 25-mm long petiole attached to the stem. The leafless petioles of 10 seedlings were capped with a loaded pipette, agar plug first, until the petiole tip broke the inner surface of the plug and the petiole came in contact with the mycelium. The other five seedlings were inoculated with agar plugs without mycelium and used as control plants. Three days after inoculation, all seedlings inoculated with S. sclerotiorum wilted and expressed symptoms similar to those observed in the field. None of the control plants showed symptoms of infection. Black sclerotia were retrieved from infected stems 2 weeks after inoculation, and the pathogen was successfully reisolated onto PDA. Several important North Dakota crops are susceptible to S. sclerotiorum. The identification of echium as a new host for S. sclerotiorum should be considered in the event that this crop is promoted as an alternative for North Dakota agriculture. To our knowledge, this is the first report on the susceptibility of echium to S. sclerotiorum. Other members of the Boraginaceae have been identified as hosts for this pathogen (1). References: (1) G. J. Boland and R. Hall. Can. J. Plant Pathol. 16:93, 1994. (2) L. E. del Río et al. (Abstr.) Phytopathology 91 (suppl.):S176, 2001.

Carotid intervention prior to or during coronary artery bypass grafting. When is it necessary?

Management of patients with advanced atherosclerosis involving the extra-cranial carotid and coronary arteries should be individualized based on symptoms and disease severity. A liberal policy to identify high-grade carotid stenosis using duplex ultrasound testing prior to coronary revascularization is recommended. Carotid intervention is efficacious for stroke reduction in patients with severe (>70% diameter reduction), bilateral internal carotid artery disease, especially if testing indicates abnormal cerebral perfusion via the circle of Willis. The morbidity of a combined carotid-coronary revascularization procedure should be less than 5%, but higher stroke and death rates can be expected in urgent cases with recent hemispheric symptoms. Patients with symptomatic >50% internal carotid artery stenosis should be considered for carotid endarterectomy at the time of coronary revascularization. Carotid angioplasty with cerebral protection is also an appropriate option in "high-risk" cardiac patients, especially in vascular centers with expertise and experience in performing this procedure. A policy of carotid endarterectomy prior to coronary bypass grafting is justified only in patients with stable coronary disease, good ejection fraction, and is best-performed using regional anesthesia.

First Report of Sclerotinia sclerotiorum on Niger (Guizotia abyssinica).

Niger is a new crop being grown in North Dakota and Minnesota for the commercial birdseed market. In 2002, approximately 60 and 150 ha of niger were grown in North Dakota and Minnesota, respectively. In September 2002, niger plants in a field located near Prosper, ND showed the following symptoms and signs: bleached, shredded, and broken stems at the basal area, and presence of white mycelium and black sclerotia (2.2 ± 0.8 mm diameter) inside the pith cavity. Approximately 40% of plants in that field showed signs or symptoms of infection. Sclerotia were collected from the pith cavity, soaked in a 0.53% NaOCL solution for 30 s, air dried, and placed in petri dishes containing potato dextrose agar (PDA). A fungal colony grew out from the plated sclerotia that subsequently produced aerial white mycelium and black sclerotia characteristic of Sclerotinia sclerotiorum (Lib.) de Bary. To confirm pathogenicity, 2 groups of 10 30-day-old niger seedlings each were inoculated using the straw test method (2) or petiole inoculation test method (1) with mycelium from a S. sclerotiorum isolate obtained from an infected niger plant; 20 seedlings served as a noninoculated control. At the time of inoculation, seedlings were healthy and approximately 14 cm high. Three days after inoculation using either method, tissue at the inoculated area turned gray. The gray lesions progressed across the majority of the seedling tissue and 1 week after inoculation, all inoculated plants were wilted and dead. S. sclerotiorum was reisolated from infected tissue that was placed on PDA. To our knowledge, this is the first report of S. sclerotiorum causing a stem rot disease of niger or any species in the Guizotia genus. Several of the major crops grown in North Dakota and Minnesota, such as canola, dry edible bean, soybean, and sunflower are susceptible to S. sclerotiorum. Growing niger in rotation with these or other susceptible crops could increase S. sclerotiorum inoculum levels and lead to severe disease outbreaks if conditions are favorable. References: (1) L. E. del Río et al. (Abstr.) Phytopathology 90(Suppl.):S176, 2000. (2) R. Petzoldt and M. H. Dickson, Annu. Rep. Bean Improv. Coop. 39:142, 1996.

Type-II endoleaks following endovascular AAA repair: preoperative predictors and long-term effects.

PURPOSE: To determine the significance of persistent type-II endoleaks and whether they can be predicted preoperatively in patients with abdominal aortic aneurysms (AAA). METHODS: The charts of all AAA patients treated with the AneuRx stent-graft at a single center from 1996 to 1998 were reviewed. Patients with <12-month follow-up or type-I endoleaks were excluded. The presence or absence of type-II endoleaks was determined from duplex imaging and computed tomographic angiography. Three groups were identified and compared: 16 patients with persistent type-II endoleaks (PE), 14 patients with transient type-II endoleaks (TE), and 16 patients with no endoleak (NE). RESULTS: The groups did not differ with regard to age, preoperative comorbidities, follow-up time, and AAA neck diameter and length. AAA diameters were 57.1 +/- 9.0 mm for NE, 63.4 +/- 11.4 mm for TE, and 55.6 +/- 4.2 mm for PE. The inferior mesenteric artery (IMA) was patent in 5 (31%) NE patients, 6 (43%) TE patients, and 13 (81%) PE patients (p < 0.01). The number of patent lumbar arteries visualized preoperatively was 0.5 +/- 1.0 in NE, 1.3 +/- 0.8 in TE, and 2.4 +/- 0.6 in PE (p < 0.0001). Patent IMAs (RR 0.82, p < 0.01) and >2 lumbar arteries (RR 0.40, p < 0.0001) were identified as independent preoperative risk factors for persistent endoleaks. There were no changes in mean diameter or volume in aneurysms with persistent endoleaks. CONCLUSIONS: No adverse clinical events were related to the presence of type-II endoleaks, but there was no decrease in aneurysm size in patients with persistent type-II leaks. Patients with a large, patent IMA, or >2 lumbar arteries on preoperative CT angiography are at higher risk for persistent type-II endoleaks.

Duplex surveillance of abdominal aortic stent grafts.

Aortic stent grafting is gaining acceptance rapidly as a durable and effective alternative to open surgery for abdominal aortic aneurysms (AAA). Unlike follow-up after open surgical procedures, postplacement surveillance protocols are necessary to ensure long-term freedom from device failure or aneurysm rupture. Surveillance protocols incorporating duplex scanning are effective and may reduce overall postplacement expenses. Specific device or patient anatomic features may be prone to failure, and familiarity with each approved device is a prerequisite to the performance of effective device surveillance studies. Mechanisms of failure of aneurysm exclusion after device placement, or "endoleak," have been described and categorized. Endoleak significance is directly related to location, duration, and influence on AAA diameter. Endoleak type also determines when and whether additional interventions are indicated. Future progress in endovascular AAA exclusion will depend in large part on the reliability and utility of cost-effective postprocedure surveillance protocols incorporating duplex ultrasound imaging.

Primary axillary-subclavian venous thrombosis: is aggressive surgical intervention justified?

Multimodal (thrombolysis, surgical decompression, venous reconstruction, oral anticoagulation) treatment of primary axillary-subclavian venous thrombosis was reviewed to assess the impact of venous patency on functional outcome. Since 1996, 7 patients (6 men, 1 woman) of ages 16-53 years (mean 33 years) presented with symptomatic acute axillosubclavian venous thrombosis as a result of a recent athletic or strenuous arm activity. Five patients had undergone previous (>2 weeks) catheter-directed thrombolysis and venous angioplasty. Diagnostic contrast venography followed by repeat catheter-directed thrombolysis demonstrated abnormal (residual stenosis [n=6] or occlusion [n=1]) axillosubclavian venous segments in all patients. Surgical intervention was performed at a mean interval of 7 days (range 1-19 days) after thrombolysis and consisted of thoracic outlet decompression with scalenectomy and 1st rib resection via a paraclavicular (n=4) or supraclavicular (n=3) approach. Medial claviculectomy or cervical rib resection was performed in 2 patients. Concomitant venous surgery was performed in all patients to restore normal venous patency by circumferential venolysis (n=7) and balloon catheter thrombectomy (n=3), or vein-patch angioplasty (n=2), or endovenectomy (n=5), or internal jugular transposition (n=2). Postoperative venous duplex testing beyond 1 month identified recurrent thrombosis in 4 patients despite therapeutic oral anticoagulation. Subsequent venous recanalization was documented in 3 patients. Poor functional outcome was associated with an occluded venous repair and extensive venous thrombosis on initial presentation. A patent or recanalized venous repair present in 6 of 7 patients was associated with good functional outcome and may justify multimodal intervention in patients with primary axillosubclavian effort thrombosis presenting with recurrent thrombosis and significant residual disease after thrombolysis.

Expanded application of in situ replacement for prosthetic graft infection.

PURPOSE: The purpose of this study was to analyze the outcome of an individualized treatment algorithm for prosthetic graft infection, including the application of in situ graft replacement, based on clinical presentation, extent of graft infection, and microbiology. METHODS: There was a retrospective review (1991-2000) of 119 patients with 68 aortoiliofemoral or 51 extracavitary (infrainguinal, 19; axillofemoral, 16; femorofemoral, 16) prosthetic graft infections presenting more than 3 months (range, 3-136 months) after implantation/revision. The treatment algorithm consisted of graft excision with or without ex situ bypass grafts for patients presenting with sepsis or graft-enteric erosion, whereas in situ replacement (autogenous vein, rifampin-bonded polyester, polytetrafluoroethylene [PTFE]) was used in patients with less virulent gram-positive graft infection, in particular infections caused by Staphylococcus epidermidis. Outcomes (death, limb loss, recurrent infection) were correlated with treatment type and infecting organism. RESULTS: In situ replacement was used in 52% of aortoiliofemoral (autogenous vein, 10; rifampin-bonded polyester, 6; PTFE, 9) and 80% of extracavitary (autogenous vein, 26; PTFE, 9; rifampin, 6) graft infections. Total graft excision with ex situ bypass was performed in 34 patients, including 21 patients with graft-enteric erosion/fistula, with a 21% operative mortality and 9% amputation rate. In situ graft replacement was used to treat 76 graft infections with a 30-day operative mortality rate of 4% and an amputation rate of 2%. Graft excision alone was performed in nine patients with one 30-day death. Gram-positive cocci were the prevalent infecting organisms of both intracavitary (59% of isolates) and extracavitary (76% of isolates) graft infections. S epidermidis was the infecting organism in 40% of patients, accounting for the expanded application of in situ prosthetic replacement using a rifampin-bonded polyester or PTFE prosthesis. During the mean follow-up interval of 26 months, recurrent graft infection developed in 3% (1 of 34) of patients after conventional treatment, 3% (1 of 36) patients after in situ vein replacement, and 10% (4 of 40) patients after in situ prosthetic graft replacement (P >.05). Failure of in situ replacement procedures was the result of virulent and antibiotic-resistant bacterial strains. CONCLUSIONS: In situ replacement was a safe and durable option in most (64%) patients presenting with prosthetic graft infection. In situ replacement with a rifampin-bonded graft was effective for S epidermidis graft infection, but when the entire prosthesis is involved with either a biofilm or invasive perigraft infection, in situ autogenous vein replacement is preferred. Virulent graft infections presenting with sepsis, anastomotic dehiscence, or graft enteric fistula should continue to be treated with total graft excision, and if feasible, staged ex situ bypass graft.

Dosimetry of the I-Plant Model 3500 iodine-125 brachytherapy source.

125I brachytherapy sources have been widely used for interstitial implants for a number of years in several tumor sites, especially the prostate. The design of the new I-Plant Model 3500 iodine source is novel, yet its characteristics are similar to those of two existing designs, Model 6711 and the Symmetra. Dosimetry parameters (including dose rate constant, radial dose function, and anisotropy function, as defined by AAPM Task Group 43) were measured with LiF thermoluminescent dosimeters in water-equivalent plastic phantoms. The dose rate constant was found by direct comparison of calibrated I-Plant Model 3500 and Model 6711 seeds in a solid water phantom, to be 1.01 (cGy/h)/U. The radial dose function and anisotropy function are similar to those of the Model 6711 and Symmetra seeds.

Use of rifampin-soaked gelatin-sealed polyester grafts for in situ treatment of primary aortic and vascular prosthetic infections.

BACKGROUND: In situ treatment of artery/graft infection has distinct advantages compared to vessel excision and extra-anatomic bypass procedures. Based on animal studies of a rifampin-soaked, gelatin-impregnated polyester graft that demonstrated prolonged in vivo antibacterial activity, this antibiotic-bonded graft was used selectively in patients for in situ treatment of low-grade Gram-positive prosthetic graft infections or primary aortic infections not amenable to excision and ex situ bypass. METHODS: In a 5-year period (1995-1999), 27 patients with prosthetic graft infection (aortofemoral, n = 18, femorofemoral, n = 3; axillofemoral, n = 1) or primary aortic infection (mycotic aneurysm, n = 3; infected AAA, n = 2) underwent excision of the infected vessel and in situ replacement with a rifampin soaked (45-60 mg/ml for 15 min) gelatin-impregnated polyester graft. All prosthetic graft infections were low grade in nature, caused Gram-positive bacteria (Staphylococcus epidermidis, 16; Staphylococcus aureus, 5; Streptococcus, 1), and were treated electively. Patients with mycotic aortic aneurysm presented with sepsis and underwent urgent or emergent surgery. RESULTS: Two (8%) patients died-1 as a result of a ruptured Salmonella mycotic aortic aneurysm and the other from methicillin-resistant S. aureus infection following deep vein replacement of an in situ replaced femorofemoral graft. No amputations or late deaths as the result of vascular infection occurred in the 25 surviving patients. Two patients developed recurrent infection caused by a rifampin-resistant S. epidermidis in a replaced aortofemoral graft limb and were successfully treated with graft excision and in situ autogenous vein replacement. Eighteen patients remain alive and clinically free of infection after a mean follow-up interval of 17 months. CONCLUSIONS: In situ replacement treatment using a rifampin-bonded prosthetic graft for low-grade staphylococcal arterial infection was safe, durable, and associated with eradication of clinical signs of infection. Failure of this therapy was the result of virulent and antibiotic-resistant bacterial strains.

Utility of duplex surveillance following iliac artery angioplasty and primary stenting.

PURPOSE: To evaluate the clinical outcome and patency rates after iliac artery angioplasty and primary stenting using a noninvasive surveillance protocol that includes duplex ultrasonography. METHODS: Sixty-seven patients (64 men; mean age 61 +/- 9 years, range 45-83) underwent stenting of 84 iliac systems for claudication (63%), rest pain (9%), tissue loss (20%), or failing lower limb bypass graft (8%). The surveillance algorithm included aortoiliac duplex scanning within 1 month and serial limb pressure measurements and femoral artery waveform analyses during follow-up. Iliac systems with a peak systolic velocity >300 cm/s and velocity ratio >2.0 by duplex and/or symptomatic or hemodynamic deterioration were considered failing and an indication for angiography. RESULTS: During intermediate-term follow-up ranging to 36 months (mean 12), life table primary, assisted primary, and secondary patency rates for the treated iliac systems were 78%, 90%, and 98%, respectively, at 18 months. Assisted primary iliac system patency at 18 months was significantly worse in the 20 (24%) limbs having an outflow bypass done with or prior to iliac stenting (83% versus 100% without bypass, p = 0.01). Indirect clinical indicators found 17 (20%) suspected failing iliac systems, in which duplex imaging correctly identified 5 of 6 recurrent iliac stenoses and facilitated secondary endovascular intervention. Three (4%) stent occlusions occurred in the treated iliac systems despite surveillance. CONCLUSIONS: Duplex surveillance after iliac stenting localizes failing inflow segments, optimizes assisted patency of the treated iliac system, and possesses greatest utility in patients with multilevel occlusive disease and outflow reconstructions.

Duplex ultrasound scanning versus computed tomographic angiography for postoperative evaluation of endovascular abdominal aortic aneurysm repair.

OBJECTIVE: The purpose of this study was to compare duplex ultrasound scanning and computed tomographic (CT) angiography for postoperative imaging and surveillance after endovascular repair of abdominal aortic aneurysm (AAA). METHODS: One hundred consecutive patients with AAA underwent endovascular (Medtronic AneuRx, stent graft) aneurysm repair and were imaged with both CT angiography and duplex ultrasound scanning at regular intervals after the procedure. Each imaging modality was evaluated for technical adequacy and for documentation of aneurysm size, endoleak, and graft patency. In concurrent scan pairs, accuracy of duplex scanning was compared with CT. RESULTS: A total of 268 CT scans and 214 duplex scans were obtained at intervals of 1 to 30 months after endovascular aneurysm repair (mean follow-up interval, 9+/-7 months). All CT scans were technically adequate, and 198 (93%) of 214 duplex scans were technically adequate for the determination of aneurysm size, presence of endoleak, and graft patency. Concurrent (within 7 days of each other) scan pairs were obtained in 166 instances in 76 patients (1-6 per patient). The maximal transverse aneurysm sac diameter measured with both methods correlated closely (r = 0.93; P <.001) without a significant difference on paired analysis. In 92% of scans, measurements were within 5 mm of each other. Diagnosis of endoleak on both examinations correlated closely (P <.001), and compared with CT, duplex scanning had a sensitivity of 81%, a specificity of 95%, a positive predictive value of 94%, and a negative predictive value of 90%. Discordant results occurred in 8% of examinations, and in none of these was the endoleak close to the attachment sites or associated with aneurysm expansion. An endoleak was demonstrated on both tests in all eight patients who had an endoleak judged severe enough to warrant arteriography. Graft patency was documented in each instance, without discrepancy, with both modalities. CONCLUSIONS: High-quality duplex ultrasound scanning is comparable to CT angiography for the assessment of aneurysm size, endoleak, and graft patency after endovascular exclusion of AAA.

A review of health-based comparative risk assessments in the United States.

Comparing the risks posed by specific environmental hazards has become attractive to policy makers and legislative bodies as an aid to budgeting and other policy decisions. This paper reviews the human health-based findings from the first federal comparative risk assessment project and subsequent reviews conducted by 15 states and local government agencies in the United States. Methods are described on conducting comparative risk assessments that include substantive involvement of the public and special interest organizations. A consolidation of the comparative risk assessments of 15 states revealed good agreement with federal health-based environmental hazard priorities and partial agreement with local-government health departments. In descending order of priority, indoor air pollutants (excluding radon), criteria air pollutants, hazardous air pollutants, indoor radon, lead contamination, inactive hazardous waste sites, and drinking water at the tap are the highest ranked environmental hazards to human health.

Magnetic resonance angiography is an accurate imaging adjunct to duplex ultrasound scan in patient selection for carotid endarterectomy.

PURPOSE: The purpose of this study was to evaluate the accuracy of magnetic resonance angiography (MRA) for categorizing the severity of carotid disease relative to duplex ultrasound scan and cerebral contrast arteriography (CA) to determine if MRA imaging could replace the need for cerebral angiography in cases of indeterminate or inadequate duplex scan imaging. METHODS: Seventy-four carotid bifurcations in 40 patients undergoing 45 carotid endarterectomies from 1996 to 1998 were imaged with duplex ultrasound scan; MRA (two-dimensional neck and three-dimensional intracranial, time-of-flight technique); and biplanar, digital subtraction cerebral arteriography. Studies were blindly reviewed by one reader who used established threshold velocity criteria for the duplex scan and the North American Symptomatic Carotid Endarterectomy Trial method for MRA and CA to determine the percentage of diameter reduction of the internal carotid artery (ICA). Disease severity was grouped into four categories (< 50%, 50%-74%, 75%-99% stenosis and occlusion), and the results of MRA and duplex ultrasound scan were compared with CA. RESULTS: Sensitivity, specificity, positive predictive value, and negative predictive value for detection of > 50% ICA stenosis were 100%, 96%, 98%, and 100% for MRA and 100%, 72%, 88%, and 100% for duplex ultrasound scan, respectively; similarly, for detection of > 75% ICA stenosis values were 100%, 77%, 76%, and 100% for MRA and 90%, 74%, 72%, and 91% for duplex ultrasound scan, respectively. Both MRA and duplex ultrasound scan accurately differentiated all cases of > 95% stenosis (n = 7) from occlusion (n = 4). Short length ICA flow gaps were present on MRA in all cases of 75% to 99% stenosis and one half of cases of CA-defined 50% to 74% stenosis. In patients with 50% to 74% stenosis, the mean angiographic stenosis was significantly greater when a flow gap was present on MRA (64% +/- 6%) versus no flow gap (57% +/- 7%) (P =.04). There was overall agreement among duplex ultrasound scan, MRA, and CA in 73% of carotids imaged. Of the 24% discordant results between MRA and duplex ultrasound scan, MRA correctly predicted disease severity in all cases, and inaccurate duplex ultrasound scan results were due to overestimation in 83% of cases. The operative plan was altered by CA findings in only one patient (2%) after duplex ultrasound scan and MRA. CONCLUSIONS: MRA can accurately categorize the severity of carotid occlusive disease. Duplex ultrasound scan facilitates patient selection for carotid endarterectomy in most cases, but adjunct use of MRA improves diagnostic accuracy for > 75% stenoses and may obviate the need for cerebral arteriography when duplex scan results are inconclusive or demonstrate borderline disease severity.

Endovascular-assisted versus conventional in situ saphenous vein bypass grafting: cumulative patency, limb salvage, and cost results in a 39-month multicenter study.

OBJECTIVE: In this retrospective multicenter study, the results of a minimally invasive method of endovascular-assisted in situ bypass grafting (EISB) versus "open" conventional in situ bypass grafting (CISB) were evaluated with a comparison of primary and secondary patency, limb salvage, and cost. METHODS: Enrolled in this study were 273 patients: 117 underwent CISB (42 femoropopliteal, 75 femorocrural) and 156 underwent EISB (41 femoropopliteal, 115 femorocrural). EISB was performed with an angioscopic Side Branch Occlusion system and an angioscopically guided valvulotome. All the patients underwent follow-up examination with serial color-flow ultrasound scanning. RESULTS: Both groups had similar comorbid risk factors for diabetes mellitus, coronary artery heart disease, hypertension, and cigarette smoking. The primary patency rates (CISB, 78.2% +/- 5% [SE]; EISB, 70.5% +/- 5%; P =.156), the secondary patency rates (CISB, 84.1% +/- 4%; EISB, 82.9% +/- 5%; P =.26), and the limb salvage rates (CISB, 85.8%; EISB, 88.4%; P =.127) were statistically similar, with a follow-up period that extended to 39 months (mean, 16.6 months; range, 1 to 40 months). In veins that were less than 2.5 to 3.0 mm in diameter, the EISB grafts fared poorly, with an increased incidence of early (12-month) graft thromboses (CISB, 10 grafts, 8.5%; EISB, 24 grafts, 15.3%). However, wound complications (CISB, 23%; EISB, 4%; P =.003), mean hospital length of stay (CISB, 6.5 days +/- 4.83; EISB, 3.2 days +/- 3.19; P =.001), and mean hospital charges (CISB, $25,349 +/- $19,476; EISB, $18,096 +/- $14,573; P =.001) were all significantly reduced in the EISB group. CONCLUSION: The CISB and EISB midterm primary and secondary patency and limb salvage rates were statistically similar. In smaller veins (< 2.5 to 3.0 mm in diameter), however, EISB is not appropriate because overly aggressive instrumentation may cause intimal trauma, with resultant early graft failure. With the avoidance of a long leg incision in the EISB group, wound complications and hospital length of stay were significantly reduced, which lowered hospital charges and justified the additional cost of the endovascular instruments. When in situ bypass grafting is contemplated, EISB in appropriate patients is a safe, minimally invasive, and cost-effective alternative to CISB.

Intraoperative duplex monitoring of infrainguinal vein bypass procedures.

PURPOSE: The purpose of this study was to evaluate intraoperative duplex scanning of infrainguinal vein bypass grafts to detect technical and hemodynamic problems, monitor their repair, and correlate findings with the incidence of thrombosis and stenosis repair rates within 90 days of operation. METHODS: Color duplex scanning was used at operation to assess vein/anastomotic patency and velocity spectra waveforms of 626 infrainguinal vein bypass grafts (in situ saphenous, 228 grafts; nonreversed translocated saphenous, 170 grafts; reversed saphenous, 147 grafts; alternative [arm, lesser saphenous], 81 grafts) to the popliteal (n = 267 grafts), infrageniculate (n = 323 grafts), or pedal artery (n = 36 grafts). The entire bypass graft was scanned after intragraft injection of papaverine hydrochloride (30-60 mg) to augment graft flow. Vein/anastomotic/artery segments with velocity spectra that indicate highly disturbed flow (peak systolic velocity, >180 cm/sec; spectral broadening; velocity ratio at site, >3) were revised. Grafts with a low peak systolic velocity less than 30 to 40 cm/s and high outflow resistance (absent diastolic flow) underwent procedures (distal arteriovenous fistula, sequential bypass grafting) to augment flow; if this was not possible, the grafts were treated with an antithrombotic regimen, including heparin, dextran, and antiplatelet therapy. RESULTS: Duplex scanning prompted revision of 104 lesions in 96 (15%) bypass grafts, including 82 vein/anastomotic stenoses, 17 vein segments with platelet thrombus, and 5 low-flow grafts. Revision rate was highest (P <.01) for alternative vein bypass grafts (27%) compared with the other grafting methods (reversed vein bypass grafts, 10%; nonreversed translocated, 13%; in situ, 16%). A normal intraoperative scan on initial imaging (n = 464 scans) or after revision (n = 67 scans) was associated with a 30-day thrombosis rate of 0.2% and a revision rate of 0.8% for duplex-detected stenosis (peak systolic velocity, >300 cm/s; velocity ratio, >3.5). By comparison, 20 of 95 bypass grafts (21%) with a residual (n = 29 grafts) or unrepaired duplex stenosis (n = 53 grafts) or low flow (n = 13 grafts) had a corrective procedure for graft thrombosis (n = eight grafts) or stenosis (n = 12 grafts; P <.001). Overall, 8% of patients with bypass grafts underwent a corrective procedure within 90 days of operation. Secondary graft patency was 99.4% at 30 days and 98.8% at 90 days (eight graft failures). CONCLUSION: The observed 15% intraoperative revision rate coupled with a low 90-day failure/revision rate (2.5%) for bypasses with normal papaverine-augmented duplex scans supports the routine use of this diagnostic modality to enhance the precision and early results of infrainguinal vein bypass procedures.

Unsymmetrical cyclic ureas as HIV-1 protease inhibitors: novel biaryl indazoles as P2/P2' substituents.

The preparation of unsymmetrical cyclic ureas bearing novel biaryl indazoles as P2/P2' substituents was undertaken, utilizing a Suzuki coupling reaction as the key step. Compound 6i was equipotent to the lead compound of the series SE063.

A rational algorithm for duplex scan surveillance after carotid endarterectomy.

PURPOSE: This study was undertaken to determine the appropriate timing and frequency of duplex ultrasound scanning after carotid endarterectomy (CEA) for the detection of high-grade stenosis caused by recurrent carotid stenosis or contralateral atherosclerotic disease progression. METHODS: In 221 patients who underwent 242 CEAs, duplex scanning was performed before, during, and after operation (in 3-month to 6-month intervals). High-grade internal carotid artery (ICA) stenosis (peak systolic velocity, >300 cm/s; diastolic velocity, >125 cm/s; ICA/common carotid artery ratio, >4) prompted the recommendation for repair. An average of four postoperative scanning procedures was performed during a mean follow-up period of 27.4 months. RESULTS: Intraoperative duplex scan results prompted the immediate revision of 12 repairs (4.9%), and one perioperative stroke (<1%) occurred. Six CEAs (2.7%) had asymptomatic recurrent stenosis (>50% diameter-reduction [DR]; systolic velocity, >125 cm/s) develop. Only one of six patients had >75% DR stenosis develop and underwent reoperation (<1% yield for CEA surveillance). The yield of surveillance of the unoperated ICA was higher (P =.003), and 12% of unoperated sides had progressive stenosis (n = 21) or occlusion (n = 3) develop, which led to seven CEAs for high-grade stenosis. Disease progression to >75% DR stenosis was five times as frequent (P =.002) in patients with >50% DR stenosis initially. All patients but one who required contralateral endarterectomy for disease progression had >50% ICA stenosis when first seen. During the follow-up period, no disabling strokes ipsilateral to an operated carotid artery occurred, but three strokes occurred in the hemisphere of the contralateral unoperated ICA. CONCLUSION: The yield of duplex scan surveillance after CEA was low. Only 13 patients (5.9%) had severe disease develop to warrant additional intervention. Progression of contralateral disease rather than restenosis was the most common abnormality that was identified. Duplex scanning at 1-year to 2-year intervals after CEA is adequate when a technically precise repair is achieved and minimal contralateral disease (<50% DR) is present. A policy of duplex scan surveillance and reoperation for high-grade stenosis was associated with a 1.6% incidence rate of disabling stroke during the follow-up period.