Treatment of Aortoiliac Occlusive Disease with the Endologix AFX Unibody Endograft.

OBJECTIVE/BACKGROUND: Aorto-bifemoral bypass remains the gold standard for treatment of aortoiliac occlusive disease (AIOD) in patients with advanced (TASC D) lesions, but has significant associated morbidity and mortality. Treatment with a unibody stent-graft positioned at the aortic bifurcation is a potential endovascular option for the treatment of AIOD. The current study examines the safety, efficacy, and early patency rates of the Endologix AFX unibody stent-graft for treatment of AIOD. METHODS: A multicenter retrospective review was conducted of patients treated exclusively for AIOD with the AFX device. Primary, assisted primary, and secondary patency rates were noted. Clinical improvement was assessed using Rutherford classification and ankle brachial index. Mean duration of follow-up was 22.2 ± 11.2 months. Ninety-one patients (56 males [62%]) were studied. RESULTS: Sixty-seven patients (74%) presented with lifestyle-limiting intermittent claudication and the remaining 24 (26%) had critical limb ischemia. Technical success was 100%. Complications included groin infection (n = 4 [4%]), groin hematoma (n = 4 [4%]), common iliac rupture (n = 4 [4%]), iliac dissection (n = 4 [4%]), and thromboembolic event (n = 3 [3%]; one femoral, one internal iliac artery, and one internal iliac with bilateral popliteal/tibial thromboemboli). Thirty-day mortality was 1% (1/91) resulting from a case of extensive pelvic thromboembolism. At 1 year, 73% of patients experienced improvement in Rutherford stage of -3 or greater compared with baseline. Nine patients (10%) required 16 secondary interventions. At all time points, primary patency rates were > 90%, assisted patency rates were > 98%, and secondary patency rates were 100%. CONCLUSION: This is the largest study to examine the use of the Endologix AFX unibody stent-graft for the treatment of AIOD. Use of the AFX stent-graft appears to be a safe and effective endovascular treatment for complex AIOD.

Bioremediation of atrazine-contaminated soil by forage grasses: transformation, uptake, and detoxification.

A sound multi-species vegetation buffer design should incorporate the species that facilitate rapid degradation and sequestration of deposited herbicides in the buffer. A field lysimeter study with six different ground covers (bare ground, orchardgrass, tall fescue, timothy, smooth bromegrass, and switchgrass) was established to assess the bioremediation capacity of five forage species to enhance atrazine (ATR) dissipation in the environment via plant uptake and degradation and detoxification in the rhizosphere. Results suggested that the majority of the applied ATR remained in the soil and only a relatively small fraction of herbicide leached to leachates (<15%) or was taken up by plants (<4%). Biological degradation or chemical hydroxylation of soil ATR was enhanced by 20 to 45% in forage treatment compared with the control. Of the ATR residues remaining in soil, switchgrass degraded more than 80% to less toxic metabolites, with 47% of these residues converted to the less mobile hydroxylated metabolites 25 d after application. The strong correlation between the degradation of N-dealkylated ATR metabolites and the increased microbial biomass carbon in forage treatments suggested that enhanced biological degradation in the rhizosphere was facilitated by the forages. Hydroxylated ATR degradation products were the predominant ATR metabolites in the tissues of switchgrass and tall fescue. In contrast, the N-dealkylated metabolites were the major degradation products found in the other cool-season species. The difference in metabolite patterns between the warm- and cool-season species demonstrated their contrasting detoxification mechanisms, which also related to their tolerance to ATR exposure. Based on this study, switchgrass is recommended for use in riparian buffers designed to reduce ATR toxicity and mobility due to its high tolerance and strong degradation capacity.

Improved HPLC-MS/MS method for determination of isoxaflutole (balance) and its metabolites in soils and forage plants.

A robust multi-residue procedure is needed for the analysis of the pro-herbicide isoxaflutole and its degradates in soil and plant materials at environmentally relevant (<1 microg kg-1) levels. An analytical method using turbo-spray and heat-nebulizer high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for the analysis of isoxaflutole (IXF) and its two metabolites, diketonitrile (DKN) and the benzoic acid metabolite (BA), at sub-microgram per kilogram levels in soil and plant samples. The average recoveries of the three compounds in spiked soil and plant samples ranged from 84 to 110% and 94 to 105%, respectively. The limits of quantification were validated at 0.06 microg kg-1 for soil and 0.3 microg kg-1 for plant samples. The limits of detection (LOD) for soil analysis were 0.01, 0.002, and 0.01 microg kg-1 for IXF, DKN, and BA, respectively. Corresponding LOD for the plant analysis method were 0.05, 0.01, and 0.05 microg kg-1. The developed method was validated using forage grass and soil samples collected from a field lysimeter study in which IXF was applied to each of four forage treatments. Forage plants and soils were sampled for analyses 25 days after IXF application to the soil. In soils, IXF was not detected in any treatment, and DKN was the predominant metabolite found. In forage plants, the concentrations of DKN and BA were 10-100-fold higher than that in soil samples, but IXF was not detected in any forage plants. The much higher proportion of BA to DKN in plant tissues (23-53%), as compared to soils (0-5%), suggested that these forages were capable of detoxifying DKN. The developed methods provided LODs at sub-microgram per kilogram levels to determine the fate of IXF and its metabolites in soils and forage plants, and they also represent considerable improvements in extraction recovery rates and detection sensitivity as compared to previous analytical methods for these compounds.

The effect of five forage species on transport and transformation of atrazine and isoxaflutole (balance) in lysimeter leachate.

A field lysimeter study with bare ground and five different ground covers was established to evaluate the effect of forage grasses on the fate and transport of two herbicides in leachate. The herbicides were atrazine (ATR; 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) and isoxaflutole [IXF; 5-cyclopropyl-4-(2-methylsulfonyl-4-trifluormethyl-benzoyl)isoxazole], which has the commercial name Balance (Aventis Crop Science, Strasbourg, France). The ground covers included orchardgrass (Dactylis glomerata L.), smooth bromegrass (Bromus inermis Leyss.), tall fescue (Festuca arundinacea Schreb.), timothy (Phleum pratense L.), and switchgrass (Panicum virgatum L.). The results suggested that the total IXF (parent + metabolites) showed higher mobility than ATR and its metabolites. Differences in the timing of transport reflected the rapid degradation of IXF to the more soluble, stable, and biologically active diketonitrile (DKN) metabolite in the system. Although grass treatments did not promote the hydrolysis of DKN, they significantly reduced its transport in the leachate through enhanced evapotranspiration. Grass treatments significantly enhanced ATR degradation in the leachates and soils, especially through N dealkylation, but they did not reduce total ATR transported in the leachate. Leachate from the orchardgrass lysimeters contained the highest proportion of ATR metabolites (64.2%). Timothy and smooth bromegrass treatments also displayed a significant increase in ATR metabolites in leachate. Grass-treated lysimeters showed higher microbial biomass carbon than bare ground. For ATR treatments, the proportion of metabolites in the leachate strongly correlated with the elevated soil microbial biomass carbon in forage treatments. In contrast, DKN degradation was poorly correlated with soil microbial biomass carbon, suggesting that DKN degradation is an abiotic process.

Acute drought stress and plant age effects on alkamide and phenolic acid content in purple coneflower roots.

The effects of acute periods of drought stress on dry weight, and alkamide and phenolic acid content in purple coneflower [Echinacea purpurea (L.) Moench, Asteraceae] roots are described. Plants subjected to brief drought stress periods for two seasons during the initial flowering stage (D-F2) produced fall-harvested roots with significantly greater cichoric acid concentration (mg/g) than corresponding well-watered controls of the same age (C-2). Total alkamide, including the tetraenoic acid isomers, and chlorogenic acid concentrations from fall-harvested roots were largely unaffected by drought stress, regardless of when the stress occurred developmentally. The alkamide concentration in three-year roots was significantly less than that in two-year roots, with an average decrease of 50.5 %. Conversely, total phenolic acids increased an average of 67.1 % for all treatments from two to three years of age. Root dry weight increased significantly by an average of 70.0 % for all drought-stressed plants from two to three years of age, compared to an increase of 35.2 % for well-watered controls. The results suggest that controlled drought stress can stimulate increased root dry weight and root cichoric acid content, and that root age is the predominant factor determining overall phytochemical content variation.

Effect of acute drought stress and time of harvest on phytochemistry and dry weight of St. John's wort leaves and flowers.

The phytochemistry and dry weight of cultivated St. John's wort are significantly influenced by acute drought stress and time of harvest. In this study, plants subjected to brief drought stress during both flower and seed development periods exhibited increased concentrations in 8 of the 10 phytochemicals examined in this study, including hypericin, pseudohypericin, chlorogenic acid, rutin, hyperoside, isoquercitrin, quercitrin, and quercetin. Increases ranged from 5% to 36% (hyperoside and rutin, respectively). Conversely, the concentrations of hyperforin and adhyperforin in flowers were decreased by an average of 10% in drought-stressed plants as compared to well-watered control plants. Acute drought stress decreased flower dry weight significantly during both drydown periods, although vegetative parameters (height, leaf dry weight and stem dry weight) were not adversely affected. While acute drought stress significantly altered the chemical yield in the leaves and flowers (phytochemical content x harvested dry weight), the time of harvest was the predominant factor determining phytochemical concentration in the organs of H. perforatum.

A human cadaveric circulation model.

Although endovascular techniques have achieved widespread acceptance, a suitable model for device development and physician training has not been available. Plastic models of the arterial tree and live animal models have significant limitations. Arterial-to-arterial flow is established in fresh frozen human cadavers after a simple thrombolytic process to achieve a more realistic model for endovascular device testing and training. Circulation can be established through most of the arterial system, including the cerebral, aortoiliac, and extremity vessels. This model offers antegrade flow in human arterial anatomy and has been used successfully for physician training and device development.

Simultaneous determination of the predominant hyperforins and hypericins in St. John's Wort (Hypericum perforatum L.) by liquid chromatography.

Hypericin and hyperforin are believed to be among the active constituents in common St. John's wort (Hypericum perforatum L.). Presently, dietary supplements are generally standardized to contain specified levels of hypericin and hyperforin, and the related compounds, pseudohypericin and adhyperforin. A rapid method was developed for simultaneous determination of these 4 active constituents by liquid chromatography (LC). A 1 g portion of dried, finely ground leaf/flower sample is extracted with 20 mL methanol for 2 h. A 0.6 mL aliquot of the crude extract is combined with 5.4 mL acetonitrile-methanol (9 + 1) and passed through a mixed solid-phase cleanup column. The eluate is examined by LC for hyperforin, adhyperforin, hypericin, and pseudohypericin on a Hypersil reversed-phase column by using simultaneous ultraviolet (284 nm) and fluorescence detection (excitation, 470 nm; emission, 590 nm). The compounds are easily separated isocratically within 8 min with a mobile phase of acetonitrile-aqueous 0.1 M triethylammonium acetate (8 + 2). Average recoveries of hyperforin and adhyperforin were 101.9 and 98.4%, respectively, for 3 sample mixtures containing concentrations ranging from approximately 0.2 to 1.5% combined hyperforins per gram dry weight. Average relative standard deviation (RSD) values for hyperforin and adhyperforin for all 3 mixtures were 18.9 and 18.0%, respectively. Average recoveries of hypericin and pseudohypericin were 88.6 and 93.3% respectively, from 3 sample mixtures containing concentrations ranging from approximately 0.2 to 0.4% combined hypericins per gram dry weight. Average RSD values for hypericin and pseudohypericin for all 3 mixtures were 3.8 and 4.2%, respectively.

Prosthetic above-knee femoropopliteal bypass grafting: five-year results of a randomized trial.

PURPOSE: This trial was designed to identify factors affecting patency rates of primary prosthetic above-knee femoropopliteal bypass grafts at 5 years. METHODS: A multi-institutional, prospective trial randomized 240 patients to compare patency rates of Gore-tex and Hemashield above-knee femoropopliteal bypass grafts at 5 years. Univariate comparisons of patency between levels of each prognostic variable were made with the Kaplan-Meier method. Variables that had a univariate P value less than.25 or those known to be important were submitted to a Cox regression analysis. RESULTS: The patient survival rate at 5 years was 59.4%. There were no differences in primary or secondary patency rates at 5 years between the two graft materials (primary, 45% vs 43% and secondary, 68% vs 68%). The risk for graft occlusion was significantly increased for patients younger than 65 years (2.1; P =.001) and for grafts with a diameter less than 7 mm (1.65; P =.0219). Variables with no apparent independent effect on patency rates were smoking status, runoff, diabetes mellitus, sex, presenting symptoms, and postoperative treatment with aspirin or Coumadin. Noninvasive test results were not predictive of subsequent graft function. CONCLUSION: Although the type of prosthetic used for above-knee femoropopliteal bypass grafts does not affect 5-year patency rates, age and graft size do influence results. These factors should be considered before a prosthetic bypass grafting procedure. Furthermore, these data should serve as a contemporary standard, with which evolving and conventional procedures can be compared.

Complete direct mammary harvest for minimally invasive coronary artery bypass.

Minimally invasive coronary artery bypass has primarily involved left internal mammary artery grafting to the left anterior descending coronary artery through a small left anterior thoracotomy incision. Harvesting of the mammary artery has been accomplished completely using a video-assisted thoracoscopic technique or incompletely to the second interspace under direct vision. With a mammary retractor, the mammary artery can be dissected completely under direct vision, thus eliminating any criticism of an incomplete harvest and any increased difficulty or expense associated with the thoracoscopic harvest. In this series, all 17 mammary arteries were successfully harvested completely under direct vision and 16 patients underwent successful minimally invasive coronary bypass.

Prosthetic above-knee femoropopliteal bypass grafting: results of a multicenter randomized prospective trial. Above-Knee Femoropopliteal Study Group.

PURPOSE: There are excellent arguments in favor of the preferential use of prosthetic grafts above the knee for the treatment of infrainguinal occlusive disease. This approach has been popularized on the basis of the seemingly acceptable results when using polytetrafluoroethylene (PTFE). However, in many centers, knitted Dacron polyester has been used in these patients, and there are several studies that show equivalent and, in some, superior results with Dacron when compared with PTFE. The purpose of this study was to examine these results in a definitive way. METHODS: A randomized prospective trial in eight clinical academic centers in the United States and Canada was initiated in 1991. Two hundred forty-four patients eligible for such a study, by virtue of criteria extant in each institution at the time, were centrally randomized. They underwent placement of either a knitted Dacron polyester graft impregnated with collagen or a thin-wall expanded reenforced PTFE graft to the above-knee popliteal artery, usually from the common femoral artery. They were frequently observed by protocol for as long as 5 years by a physical examination noninvasive hemodynamic study, including duplex scanning in many instances. Continuing patency was noted, as were other potential adverse outcome events. The data were analyzed by the log-rank test for cumulative patency and expressed as Kaplan-Meier curves. Data were further analyzed with a Cox proportional hazards model. RESULTS: There were no differences in graft groups in demographic or comorbid factors. The procedural mortality rate was zero, and the morbidity rate was low (6.5%). The long-term patient survival rate was excellent (77% at 3 years). At the end of these years, no statistical significance in primary or secondary patency rates was observed between the two grafts (primary patency rate, 62% +/- 14.4% for Dacron; 57% +/- 15.5% for PTFE). No unexpected adverse outcomes on limb status were noted. Patency rates in both graft groups were inferior in patients who received small grafts (5 to 6 mm vs 7 to 8 mm; hazards ratio, 4.15) and younger (<65 years) smoking patients. CONCLUSIONS: The fact that these two prosthetic grafts performed in equivalent fashion in a controlled, well-conducted prospective study is not surprising in spite of the previous work that suggested differences. If the preferential use of synthetic bypass grafts above the knee is to be used, it should be restricted to older nonsmokers with favorable anatomy. In that instance, the choice of graft material will depend on handling characteristics and cost. Above-knee prostheses should be only selectively used in younger, smoking patients, and graft size should be carefully considered in patients who undergo this operation.

Aortocoronary bypass with saphenous vein graft. Seven-year follow-up. 1973.

A 42-year-old man had extensive occlusive disease of the coronary artery and angina pectoris. An autogenous saphenous vein bypass from the ascending aorta to the anterior descending coronary artery was performed on Nov 23, 1964. The patient suffered an asymptomatic anterior myocardial infarction during operation but made an uncomplicated recovery. Seven years after the operation, the graft functions with normal left ventricular hemodynamics, while the occlusive process has produced obstruction of the left main coronary artery and almost complete occlusion of the right coronary artery. To our knowledge, this is the first successful case of a saphenous vein-coronary artery bypass with the longest follow-up of a functioning coronary vein bypass graft.

Boric acid-phenolic relationships within the Pinus echinata-Pisolithus tinctorius ectomycorrhizal association.

At germination, container-grown shortleaf pine seedlings were inoculated with Pisolithus tinctorius (Pers.) Coker & Couch or left uninoculated, and both groups were fertilized semiweekly with a modified Hoagland's solution supplemented with 0 or 0.4 mM boric acid. After 12, 16 and 24 weeks, seedling root tissue was analyzed for ectomycorrhizal colonization, phenolic concentration and phenoloxidase activity. In addition, phenoloxidase activity was assayed in P. tinctorius that had been cultured in a liquid medium containing boric acid. Inoculation with P. tinctorius increased the root phenolic concentration of 16- and 24-week-old seedlings, and increased root phenoloxidase activity in 12-, 16- and 24-week-old seedlings. Fertilization with boric acid reduced the phenolic concentration of P. tinctorius ectomycorrhizae after 24 weeks. Although boric acid fertilization did not affect the phenoloxidase activity of 12-, 16- and 24-week-old inoculated roots, or that of 16- and 24-week-old uninoculated roots, it increased the phenoloxidase activity of P. tinctorius grown in vitro and 12-week-old uninoculated roots. We conclude that boric acid fertilization influences the phenolic relations of the shortleaf pine-P. tinctorius ectomycorrhizal association, possibly through a boric acid-induced increase in phenoloxidase activity.

Pulmonary capillary hemangiomatosis: a clinicopathologic review.

Pulmonary capillary hemangiomatosis is a locally aggressive benign vascular neoplasm of the lung characterized by the presence of numerous cytologically benign thin-walled capillary-sized blood vessels proliferating diffusely through the pulmonary interstitium, in and around pulmonary vessels and airways. Pulmonary capillary hemangiomatosis is a rare disease characterized by pulmonary hypertension and a slowly progressive clinical course; it is frequently misdiagnosed clinically as primary pulmonary hypertension and veno-occlusive disease. The purpose of this review is to describe the clinical, radiologic, and histologic features of this rare form of pulmonary vascular neoplasm, which may present considerable diagnostic problems to both the clinician and the histopathologist. Fourteen cases of pulmonary capillary hemangiomatosis have been previously reported. In this review we describe the fourth case of pulmonary capillary hemangiomatosis in which the diagnosis was made antemortem, as well as the fourth to undergo lung transplantation.

Accessory mitral valve tissue: an increasingly recognized cause of left ventricular outflow tract obstruction.

Subvalvar left ventricular outflow tract obstruction (LVOTO) may be secondary to congenital abnormalities of the mitral valve, including abnormal attachments of the anterior leaflet of the mitral valve, parachute mitral valve, and accessory valve tissue. Successful correction of LVOTO due to accessory mitral valve tissue is reported in a 44-year-old man. Twenty-five patients with LVOTO due to accessory mitral valve tissue have been previously reported; however, only a few have been recognized preoperatively. A high index of suspicion is necessary for preoperative and intra-operative recognition and correction of the abnormality.

Retroperitoneal lymphocele after abdominal aortic surgery.

Lymphoceles may occur as a result of lymphatic injury during abdominal aortic surgery. These lymphatic collections may occur as a retroperitoneal mass or as groin lymphoceles. Four cases are presented in which persistent retroperitoneal lymphoceles were discovered 2 to 8 years after surgery. Reexploration of the groin and repeated aspirations of lymphatic fluid failed to control the drainage. Reexploration of the retroperitoneum documented lymphatic injury, which was controlled by ligation of the lymphatics with suture. A review of the literature discloses five similar reported cases of retroperitoneal lymphocele and 12 cases of chylous ascites after abdominal aortic surgery. Clearly, avoiding lymphatic injury or immediate repair of any lymphatic injuries will prevent this problem. Once a persistent lymphocele has developed, aspiration will establish the diagnosis. Our experience would suggest that reexploration of the retroperitoneum is required to control the drainage and to prevent possible graft infection.

Reoperative median sternotomy.

Sternal reentry for reoperative cardiac procedures poses a substantial risk of technical problems. A simple technique for sternal reentry is described that is both expeditious and safe.

Tibial artery pseudoaneurysms: delayed complication of balloon catheter embolectomy.

Although complications of balloon catheter embolectomy are infrequent, the injury potential of these catheters is well recognized. This article describes a case of multiple tibial artery pseudoaneurysms that appeared 4 years after embolectomy in a 42-year-old man with otherwise normal arteries. The patient was treated by internal aneurysmorrhaphy without sequelae. A literature review of balloon catheter injuries yielded 46 cases categorized as arterial disruption (29), intimal injury (12), or catheter malfunction (5). These resulted in hemorrhage (13 cases), arteriovenous fistula (12), pseudoaneurysm (four), thrombosis (three), dissection (five), accelerated atherosclerosis (four), and catheter fragment embolism (five). Of these complications, only 41% were recognized during the initial operation. Direct observation detected 32% of these, whereas 68% were shown only by completion arteriography. Complications recognized during initial operation were more frequently asymptomatic without further surgery (84%) than those detected postoperatively (30%, p less than 0.001). Completion arteriography detected 87% of balloon catheter complications compared with only 23% of complications recognized intraoperatively without arteriography (p less than 0.001). We conclude that delicate technique, completion arteriography, prompt surgical treatment, and extended follow-up are important components of balloon catheter embolectomy.

Boron fertilization and carbohydrate relations in mycorrhizal and nonmycorrhizal shortleaf pine.

Eight-week-old shortleaf pine seedlings (Pinus echinata Mill.) with and without ectomycorrhizae formed by Pisolithus tinctorius were treated for two to eight weeks with 25 microg borate ml(-1) solution applied either to the soil, or as a foliar spray, or in both ways. Control seedlings were fertilized only with modified Hoagland's solution containing 0.03 microg ml(-1) borate. Five sugars (pinitol, fructose, glucose, myoinositol and sucrose) were quantitated in both mycorrhizal and nonmycorrhizal roots by gas-liquid chromatography. Fertilization with boron increased the total carbohydrate content of mycorrhizal roots except in seedlings receiving foliar applications of boron. Foliar + soil fertilization yielded a 24% increase in total carbohydrates in mycorrhizal roots, whereas foliar fertilization alone decreased the total carbohydrate content. Carbohydrate content of nonmycorrhizal roots was significantly increased only by soil fertilization with boron. Individual sugars were affected less by boron fertilization in nonmycorrhizal roots than in ectomycorrhizal roots. However, significant increases in sugars in response to boron fertilization were observed in both ectomycorrhizal and nonmycorrhizal plants.

Bedside percutaneous tracheostomy: experience with 55 elective procedures.

Over a 24-month period, tracheostomy was performed in 55 patients using a percutaneous, wire-guided, dilatational technique. All such procedures were undertaken at the patient's bedside in the intensive care unit, with the patient under local anesthesia and mechanically ventilated through an oral endotracheal tube. A variety of wire-guides, dilators, and tracheal tubes were used as experience and proficiency were gained with the approach, and eventually, a simple modification of a standard low-pressure cuffed endotracheal tube was found to facilitate the procedure. The percutaneous method was found to be rapid and simple, to leave almost no cosmetic deformity, and to be almost totally free from infectious complications. This technique should be considered for routine use in critically ill, ventilator-dependent patients.