Adjunctive primary stenting of Zenith endograft limbs during endovascular abdominal aortic aneurysm repair: Implications for limb patency

ObjectiveEndograft limb occlusion is an infrequent but serious complication of endovascular abdominal aortic aneurysm (AAA) repair. The insertion of additional stents within the endograft limb may prevent future occlusion. This study evaluates limb patency with and without adjunctive stenting of endograft limbs at the time of endovascular AAA repair.MethodsWe performed a retrospective review of 248 patients who underwent endovascular abdominal aortic aneurysm repair with the Zenith AAA endovascular graft between 1999 and 2004. Among these patients, two groups were identified: 64 patients with adjunctive stents placed in 85 limbs and 184 patients without additional bare stent placement in endograft limbs at the time of endovascular AAA repair.ResultsWomen comprised 23% of stented and 11% of unstented patients (P = .02). The mean length of follow-up in the stented and unstented groups was 2.0 years. There were 13 instances of limb thrombosis in 13 patients (5.2% of patients, 2.7% of limbs), all in the unstented group. No limb occlusions occurred in the presence of adjunctive bare metal stents. Seventy-three percent of the occlusions occurred ≤6 months of endovascular AAA repair. Two patients (15%) had no symptoms of lower-extremity ischemia despite graft limb occlusion and did not undergo intervention. The others underwent thrombectomy (n = 2), thrombectomy with bare stent placement (n = 3), femoral-femoral bypass (n = 4), thrombolysis (n = 1), and thrombolysis with bare stent placement (n = 1). Of the seven who underwent thrombectomy or thrombolysis, three had no additional stents placed at the secondary procedure, and two of these three went on to rethrombose. By life-table analysis, primary patency at 3 years in the stented and nonstented limbs was 100% ± 0% and 94% ± 3%, respectively (P = .05).ConclusionsThe intraoperative insertion of additional bare metal stents appeared to eliminate the risk of thrombosis and was without complication. Of the 85 stented limbs in this series, not one occluded. The overall rate of limb thrombosis was low, with most limb occlusions occurring ≤6 months of stent-graft insertion, and would probably have been even lower had we been able to identify all high-risk cases for prophylactic adjunctive stenting. Limb occlusion denotes an underlying problem with the graft, which if left untreated after thrombectomy or thrombolysis will lead to rethrombosis. Postoperative imaging was of little value in detecting impending limb occlusion. Based on these findings, we believe one should identify and stent any limbs that appear to be at risk for thrombosis, but this study lacks the data to predict which limbs need stenting

Endovascular treatment of thoracoabdominal aortic aneurysms

ObjectiveThis study assessed the role of multibranched stent grafts for thoracoabdominal aortic aneurysm (TAAA) repair.MethodsSelf-expanding covered stents were used to connect the caudally directed cuffs of an aortic stent graft with the visceral branches of a TAAA in 22 patients (16 men, 6 women) with a mean age of 76 ± 7 years. All patients were unfit for open repair, and nine had undergone prior aortic surgery. Customized aortic stent grafts were inserted through surgically exposed femoral (n = 16) or iliac (n = 6) arteries. Covered stents were inserted through surgically exposed brachial arteries. Spinal catheters were used for cerebrospinal fluid pressure drainage in 22 patients and for and spinal anesthesia in 11.ResultsAll 22 stent grafts and all 81 branches were deployed successfully. Aortic coverage as a percentage of subclavian-to-bifurcation distance was 69% ± 20%. Mean contrast volume was 203 mL, mean blood loss was 714 mL, and mean hospital stay was 10.9 days. Two patients (9.1%) died perioperatively: one from guidewire injury to a renal arterial branch and the other from a medication error. Serious or potentially serious complications occurred in 9 of 22 patients (41%). There was no paraplegia, renal failure, stroke, or myocardial infarction among the 20 surviving patients. Two patients (9.1%) underwent successful reintervention: one for localized intimal disruption and the other for aortic dissection, type I endoleak, and stenosis of the superior mesenteric artery. One patient has a type II endoleak. Follow-up is >1 month in 19 patients, >6 months in 12, and >12 months in 8. One branch (renal artery) occluded for a 98.75% branch patency rate at 1 month. The other 80 branches remain patent. There are no signs of stent graft migration, component separation, or fracture.ConclusionsMultibranched stent graft implantation eliminates aneurysm flow, preserves visceral perfusion, and avoids many of the physiologic stresses associated with other forms of repair. The results support an expanded role for this technique in the treatment of TAAA

Sox2 maintains self-renewal of tumor initiating cells in osteosarcomas

Tumors are thought to be sustained by a reservoir of self-renewing cells, termed tumor initiating cells or cancer stem cells. Osteosarcomas are high-grade sarcomas derived from osteoblast progenitor cells and are the most common pediatric bone malignancy. In this report we show that the stem cell transcription factor Sox2 is highly expressed in human and murine osteosarcoma cell lines as well as in tumor samples. Osteosarcoma cells have increased ability to grow in suspension as osteospheres, that are greatly enriched in expression of Sox2 and the stem cell marker, Sca-1. Depletion of Sox2 by shRNAs in independent murine osteosarcoma-derived cells drastically reduces their transformed properties in vitro and their ability to form tumors. Sox2-depleted osteosarcoma cells can no longer form osteospheres, and differentiate into mature osteoblasts. Concomitantly, they exhibit decreased Sca-1 expression and upregulation of the Wnt signaling pathway. Thus, despite other mutations, these tumor cells maintain a proliferative requirement for Sox2. Our data indicate that Sox2 is required for osteosarcoma cell self-renewal, and that Sox2 antagonizes the pro-differentiation Wnt pathway, that can in turn reduce Sox2 expression. These studies define Sox2 as a survival factor and a novel biomarker of self-renewal in osteosarcomas, and support a tumor suppressive role for the Wnt pathway in tumors of mesenchymal origin. Our findings could provide the basis for novel therapeutic strategies based on inhibiting Sox2 or enhancing Wnt signaling for the treatment of osteosarcomas

SS25. Cryopreserved Venous Allograft: An Alternative Conduit for Reconstruction of Infected Prosthetic Aortic Grafts

Olivé Milián, ArmandPla general picat del mosaic format per tres cercles: el central, amb un sol de color ocre sobre un cel blau. El sol, somrient, està encarat cap al sud. Aquest està envoltat d'un primer anell dentat i un segon on s'hi representen les fases d

Endoleak after endovascular repair of abdominal aortic aneurysm

AbstractPurpose: We sought to assess the role of endovascular techniques in the management of perigraft flow (endoleak) after endovascular repair of an abdominal aortic aneurysm. Method: We performed endovascular repair of abdominal aortic aneurysm in 114 patients, using a variety of Gianturco Z-stent–based prostheses. Results were evaluated with contrast-enhanced computed tomography (CT) at 3 days, 3 months, 6 months, 12 months, and every year after the operation. An endoleak that occurred 3 days after operation led to repeat CT scanning at 2 weeks, followed by angiography and attempted endovascular treatment. Results: Endoleak was seen on the first postoperative CT scan in 21 (18%) patients and was still present at 2 weeks in 14 (12%). On the basis of angiographic localization of the inflow, the endoleak was pure type I in 3 cases, pure type II in 9, and mixed-pattern in 2. Of the 5 type I endoleaks, 3 were proximal and 2 were distal. All five resolved after endovascular implantation of additional stent-grafts, stents, and embolization coils. Although inferior mesenteric artery embolization was successful in 6 of 7 cases and lumbar embolization was successful in 4 of 7, only 1 of 11 primary type II endoleaks was shown to be resolved on CT scanning. There were no type III or type IV endoleaks (through the stent-graft). Endoleak was associated with aneurysm dilation two cases. In both cases, the aneurysm diameter stabilized after coil embolization of the inferior mesenteric artery. There were two secondary (delayed) endoleaks; one type I and one type II. The secondary type I endoleak and the associated aneurysm rupture were treated by use of an additional stent-graft. The secondary type II endoleak was not treated. Conclusions: Type I endoleaks represent a persistent risk of aneurysm rupture and should be treated promptly by endovascular means. Type II leaks are less dangerous and more difficult to treat, but coil embolization of feeding arteries may be warranted when leakage is associated with aneurysm enlargement. (J Vasc Surg 2001;34:98-105.

Chemical Synthesis of Staphyloferrin B Affords Insight into the Molecular Structure, Iron Chelation, and Biological Activity of a Polycarboxylate Siderophore Deployed by the Human Pathogen

Staphyloferrin B (SB) is a citrate-based polycarboxylate siderophore produced and utilized by the human pathogen Staphylococcus aureus for acquiring iron when colonizing the vertebrate host. The first chemical synthesis of SB is reported, which enables further molecular and biological characterization and provides access to structural analogues of the siderophore. Under conditions of iron limitation, addition of synthetic SB to bacterial growth medium recovered the growth of the antibiotic resistant community isolate S. aureus USA300 JE2. Two structural analogues of SB, epiSB and SBimide, were also synthesized and employed to investigate how epimerization of the citric acid moiety or imide formation influence its function as a siderophore. Epimerization of the citric acid stereocenter perturbed the iron-binding properties and siderophore function of SB as evidenced by experimental and computational modeling studies. Although epiSB provided growth recovery to S. aureus USA300 JE2 cultured in iron-deficient medium, the effect was attenuated relative to that of SB. Moreover, SB more effectively sequestered the Fe(III) bound to human holo-transferrin, an iron source of S. aureus, than epiSB. SBimide is an imide analogous to the imide forms of other citric acid siderophores that are often observed when these molecules are isolated from natural sources. Here, SBimide is shown to be unstable, converting to native SB at physiological pH. SB is considered to be a virulence factor of S. aureus, a pathogen that poses a particular threat to public health because of the number of drug-resistant strains emerging in hospital and community settings. Iron acquisition by S. aureus is important for its ability to colonize the human host and cause disease, and new chemical insights into the structure and function of SB will inform the search for new therapeutic strategies for combating S. aureus infections.Alfred Benzon Foundation (Postdoctoral fellowship)Pacific Southwest Regional Center of ExcellenceAlfred P. Sloan Foundatio

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure