Metal organic framework encapsulated tamavidin-Gluc reporter: application in COVID-19 spike antigen bioluminescent immunoassay.

Enzyme linked immunosorbent assay (ELISA) is one of the most utilized serological methods to diagnose and identify etiologic agents of many infectious diseases and other physiologically important analytes. ELISA can be used either alone or adjunct to other diagnostic methods such as molecular arrays, and other serological techniques. Most ELISA assays utilize reagents that are proteinaceous in nature, which are not very stable and require cold-chain transport systems. Development of a desirable immunoassay requires stability of reagents used and its ability to be stored at room temperature without sacrificing the activity of the reagents or the protein of interest. Metal organic frameworks (MOFs) are a rapidly emerging and evolving class of porous polymeric materials used in a variety of biosensor applications. In this study, we introduce the use of MOFs to stabilize a universal reporter fusion protein, specifically, avidin-like protein (Tam-avidin2) and the small bioluminescent protein Gaussia luciferase (Gluc) forming the fusion reporter, tamavidin2-Gluc (TA2-Gluc). This fusion protein serves as a universal reporter for any assays that utilize biotin-avidin binding strategy. Using SARS-CoV2 S1 spike antigen as the model target antigen, we demonstrated that encapsulation of TA2-Gluc fusion protein using a nano-porous material, zeolitic imidazolate framework-8 (ZIF-8), allows us to store and preserve this reporter protein at room temperature for over 6 months and use it as a reporter for an ELISA assay. Our optimized assay was validated demonstrating a 0.26 µg mL-1 limit of detection, high reproducibility of assay over days, detection of spiked non-virulent SARS-COV2 pseudovirus in real sample matrix, and detection in real COVID-19 infected individuals. This result can lead to the utilization of our TA2-Gluc fusion protein reporter with other assays and potentially in diagnostic technologies in a point-of-care setting.

Modification of protocol with one extra drop of endovascular cyanoacrylate improved closure rates in incompetent great saphenous veins.

INTRODUCTION: Great saphenous vein diameter (GSV) of >8 mm was predictor of recanalization following Venaseal cyanoacrylate treatment. The aim of this study was to report our modified protocol with a single extra-drop for treatment for GSV>8 mm, and comparative duplex results in closure rates. METHODS: Patients in our single-centre registry treated with Venaseal were followed up by serial duplex examinations at week 1 and month(s)- 1, 6, 12, 18, 24, and then annually. The primary endpoint was successful obliteration of the GSV, secondary endpoints were closure distance from Saphenofemoral junction (SFJ), presence of endovenous glue-induced thrombosis (EGIT) or deep vein thrombosis. RESULTS: A total of 243 legs in 123 consecutive patients with duplex-proven SFJ/GSV incompetence were included in this study between September 2014 and October 2020. The median duplex follow-up period of this cohort of patients was 24 (range 0.2-58) months. Comparing closure rates in GSV diameter ≥8 mm treated with normal protocol, the 'extra-drop protocol' significantly improved closure rates (p = .034). However, the closure rates of ≥8 mm GSV treated with 'extra-drop protocol' was still not as good as GSV <8 mm (p < .001). There were no statistically significant differences in the stump distance between the three groups and no difference in the occurrence of EGIT. There were no deep vein thrombosis. CONCLUSION: Our experience showed that VenaSeal cyanoacrylate worked best in GSV<8 mm diameter. Even in GSV diameter of ≥8 mm which has a higher recanalization rate on follow-up duplex, our modified extra-drop protocol significantly improved the closure rates, and did not predispose to development of EGIT.

A Novel Stromal Fibroblast-Modulated 3D Tumor Spheroid Model for Studying Tumor-Stroma Interaction and Drug Discovery.

Tumor-stroma interactions play an important role in cancer progression. Three-dimensional (3D) tumor spheroid models are the most widely used in vitro model in the study of cancer stem/initiating cells, preclinical cancer research, and drug screening. The 3D spheroid models are superior to conventional tumor cell culture and reproduce some important characters of real solid tumors. However, conventional 3D tumor spheroids are made up exclusively of tumor cells. They lack the participation of tumor stromal cells and have insufficient extracellular matrix (ECM) deposition, thus only partially mimicking the in vivo conditions of tumor tissues. We established a new multicellular 3D spheroid model composed of tumor cells and stromal fibroblasts that better mimics the in vivo heterogeneous tumor microenvironment and its native desmoplasia. The formation of spheroids is strictly regulated by the tumor stromal fibroblasts and is determined by the activity of certain crucial intracellular signaling pathways (e.g., Notch signaling) in stromal fibroblasts. In this article, we present the techniques for coculture of tumor cells-stromal fibroblasts, time-lapse imaging to visualize cell-cell interactions, and confocal microscopy to display the 3D architectural features of the spheroids. We also show two examples of the practical application of this 3D spheroid model. This novel multicellular 3D spheroid model offers a useful platform for studying tumor-stroma interaction, elucidating how stromal fibroblasts regulate cancer stem/initiating cells, which determine tumor progression and aggressiveness, and exploring involvement of stromal reaction in cancer drug sensitivity and resistance. This platform can also be a pertinent in vitro model for drug discovery.

Cyanoacrylate glue used to treat great saphenous reflux: Measures of outcome.

Introduction This is a single-center clinical study for the evaluation of safety, efficacy, and performance of endovenous cyanoacrylate (Sapheon Venaseal Closure System, now Medtronic Medical) for the treatment of great saphenous vein (GSV) reflux. Methods Primary outcome measures included the GSV obliteration, with clinical recurrence on follow up as detected by serial clinical and duplex examinations of patients at 1 week, 1 month, 6 months, and 1 year. Venous clinical severity score (VCSS), Aberdeen varicose vein questionnaire (AVVQ), Short Form Health Survey 36 Item (SF-36) questionnaires were used at clinical follow up. Diameter of the GSV, treatment length of the GSV, and pretreatment clinical severity of the varicose vein were analyzed to predict recanalization using Cox regression analysis. Results Fifty-seven legs in 29 patients with primary varicose veins were included. One week follow-up duplex showed successful obliteration of the GSV in all except one of the legs. Two legs had minimal extension of thrombus to deep vein. None of the patients had deep venous thrombosis. All the patients were discharged the same day of operation. Median time to return to work was 1 day (range 1-16 days). Our VCSS, AVVQ, and the SF-36 physical and mental scores changed from a mean of 6.91, 23.66, 44.24, 54.26 at baseline to 2.43, 6.10, 43.85, 52.50 at 1 month post operation, respectively. Kaplan-Meier analysis showed that the GSV closure rates were 98.2%, 94.3%, 89.7%, and 78.5% at post-op 1 week, 1 month, 6 months, and 1 year, respectively. With median follow-up period of 9 months (range 1-13 months), no clinical recurrence of varicosity was observed. Mean GSV diameter ≥8 mm was a significant predictor for recanalization (hazard ratio 6.92, 95%CI 1.34-35.67, p = 0.021). Conclusion This study showed that the use of endovenous cyanoacrylate in the treatment of the GSV reflux was safe. All patients had symptomatic improvement as shown by the VCSS and AVVQ.

Outcome and risk factor analysis of patients who underwent open infrarenal aortic aneurysm repair.

INTRODUCTION: The aim of this study was to evaluate the short- and long-term outcomes in patients who underwent open infrarenal aortic aneurysm repair. METHODS: Consecutive patients who underwent open repair of infrarenal aortic aneurysms at our institution from July 1(st) 1990 to June 30(th) 2012 were reviewed from a prospective collected departmental database. Short-term outcomes included 30-day mortality and peri-operative complications. Independent risk factors to predict 30-day mortality were identified. Long-term survival and secondary interventions were also reported. RESULTS: Three hundred and eighty-three patients (317 males, median age 72 years with a range of 15-90 years) underwent open infrarenal aortic aneurysm repair during the period, of whom 266 (69.5%) were elective, 18 (4.7%) were urgent for symptomatic but nonruptured cases, and 99 (25.8%) were emergency procedures for ruptured aneurysms. Mean aneurysm size was 6.5 cm (ranging from 2.5 cm to15 cm). All patients were followed up for at least 24 months with a mean follow up period 163 months. Overall 30-day mortality was 11.0% (36.4% for ruptured cases, 11.1% for symptomatic cases, and 1.5% for elective cases; p < 0.001). Preexisting renal disease and ruptured aneurysms were independent risk factors for 30-day mortality (p = 0.001 and p = 0.006 respectively). Systemic complications included 50 cardiac events, 52 respiratory events, six renal events, three cerebral vascular accidents, and one deep vein thrombosis/pulmonary embolism. Local complications included two anastomotic/graft hemorrhage, 10 distal thrombosis/embolisms, five bowel ischemias, one spinal cord ischemia, and 17 wound complications. The ruptured group presented survival rates of 53.5%, 50.5%, 47.5%, 42.3%, 38.0%, 21.9%, and 12.5% at 1 year, 2 years, 3 years, 4 years, 5 years, 10 years, and 15 years, respectively; while nonruptured survival rates were 91.5%, 88.0%, 83.7%, 78.3%, 73.0%, 43.0%, and 25.3%, respectively (log rank p < 0.001). For those who died 30 days after the operation, only six patients (1.8%) died from aneurysm related mortality. A total of three (0.9%) patients underwent late re-interventions, one for late aorto-enteric fistulae and two for anastomotic pseudoaneurysms. CONCLUSION: In the current era of endovascular repair, open infrarenal aneurysm repair is effective and durable, and has very low secondary interventions rates.

Primary stenting of femoropopliteal atherosclerotic lesions using new helical interwoven nitinol stents.

BACKGROUND: The Supera helical interwoven nitinol stent has enhanced flexibility in counteracting fractures when placed in the femoropopliteal arteries and may improve patency. The aim of this study is to assess the early results of the Supera stent in symptomatic patients with femoropopliteal atherosclerotic lesions. METHODS: From October 2011 to April 2013, patients with symptomatic femoropopliteal lesions were treated with angioplasty and primary stenting using the Supera stent. They were followed up at 1, 3, 6, and 12 months with clinical, duplex, and radiographic assessments. Failure was defined as >50% restenosis of the target lesion on duplex ultrasound imaging or stent fracture on X rays. RESULTS: A total of 78 consecutive patients (46 males, 32 females) with 82 legs, mean age of 78.5 years (range, 57-97 years) were included. Symptoms of claudication, rest pain, and tissue loss were 48 (59%), 8 (10.1%), and 30 (37%), respectively. Ninety-six Supera stents were inserted in total. In 44 (53.7%) of the legs, stents were extended to the popliteal segments. The mean stented length was 12.6 cm (range, 4.0-38.0 cm). The primary patency rates at 6 and 12 months were 83.5% and 78.6%, respectively. The ankle brachial index increased from 0.58 ± 0.16 preoperative to 0.87 ± 0.14 postoperative. There were no stent fractures. Patency rate was not affected by severity of symptoms, stent lengths, femoro/popliteal stents (log-rank test, P = .50, .13, .52). All the patients reported symptomatic improvement. There was no procedural- or device-related morbidity or mortality, no major amputation after revascularization, and 10 patients died of unrelated cardiopulmonary/renal causes on follow-up. CONCLUSIONS: Our early experience shows that the Supera stents are effective in our cohort of elderly patients, with acceptable patency rates. There were no stent fractures so far even with stenting of the popliteal segments.

Surgeons' static posture and movement repetitions in open and laparoscopic surgery.

BACKGROUND: There is increasing concern about the surgeon maintaining a static posture during laparoscopic surgery, which can contribute to musculoskeletal disorders. A series of studies are being conducted in Hong Kong examining the surgeons' real-time movements and electromyography in the operating theater during different operations. The present paper examines the postures and movements of surgeons during real-time open and laparoscopic procedures. MATERIALS AND METHODS: Fourteen surgeons participated in the study (12 men, 2 women). Cervical spine movements were measured using a biaxial inclinometer attached to the surgeon's head via a headband. Biaxial electrogoniometers were attached to the surgeon's bilateral shoulder joints. Real-time joint movements in sagittal and coronal planes were recorded during open and laparoscopic surgeries for periods ranging from 30 to 80 min. RESULTS: Surgeons generally maintained a flexed neck posture during open surgery and a more extended neck posture during laparoscopic procedures. There were statistically significant differences in mean neck posture and mean left shoulder abduction posture between the two types of surgery. Laparoscopic procedures showed a trend for longer duration in static posture in the neck, while open procedures showed trends for higher frequencies of movements. CONCLUSIONS: This study presented a novel approach to quantify the physical workload of surgeons using biomechanical parameters to describe duration of static posture and repetitiveness of movements. Results showed that long durations of static postures in laparoscopic surgery were closely associated with low-level muscle tension, which may contribute to an increased risk of surgeons developing musculoskeletal disorders.

Prevalence of abdominal aortic aneurysm in Chinese patients with severe coronary artery disease.

BACKGROUND: The Asian population is believed to have lower incidence of abdominal aortic aneurysm (AAA), and hence, the benefit of screening is uncertain. The size of native aorta in Asians, which shall affect the definition of AAA, has also never been reported. Our study investigated the prevalence of AAA and the infra-renal aortic diameter (AD) in Chinese patients with severe coronary artery disease. METHODS: This is a prospective observational study of infra-renal aortic size for patients who had coronary artery bypass surgery by ultrasound. The patients' demographics, important co-morbidities and maximum AD were recorded. RESULTS: The study included 624 consecutive Chinese patients (mean age = 63.2 years). The mean maximum infra-renal AD was 17.5 mm for men and 14.8 mm for women. The presence of AAA was defined as maximum AD greater than 30 mm. The result was also compared with an alternate definition that defines AAA as maximum AD of greater than 1.5 times of the group's mean. Eleven patients had an AD greater than 30 mm, and the prevalence of AAA was only 1.8%. With AAA defined as maximum AD of 1.5 times greater than the group's mean, 19 patients had AAA. The prevalence of AAA in this high-risk group would become 3% overall. CONCLUSION: The prevalence of AAA in Chinese patients was low, and the result did not support routine screening. The smaller mean infra-renal AD in Chinese merits validation by large-scale study and consideration when deciding threshold for small AAA repair in our locality.

Successful endovascular infrarenal aneurysm repair in a patient with situs inversus totalis.

Situs inversus totalis is a rare autosomal recessive developmental anomaly. There are very few reports in the published literature of abdominal aortic aneurysm in patient with situs inversus totalis, all of whom underwent open aneurysm repair. This is the first case in the world's literature to describe a patient with situs inversus totalis who had a successful endovascular infrarenal aneurysm repair. Although endovascular infrarenal aneurysm repair should not be more challenging, the endovascular approach may decrease risk of potential errors because of unfamiliar anatomy. Technical considerations in performing endovascular procedures in patients with situs inversus totalis are discussed in this article.

Work-related musculoskeletal symptoms in surgeons.

INTRODUCTION: Surgeons are a unique group of healthcare professionals who are at risk for developing work-related musculoskeletal symptoms (WMS). The diversity of operating skills for laparoscopic and endovascular procedures impose different physical demands on surgeons, who also work under time pressure. The present study aims to examine the physical and psychosocial factors and their association with WMS among general surgeons in Hong Kong. METHOD: A survey was conducted among surgeons working in the General Surgery departments in public hospitals of Hong Kong. Over 500 questionnaires were mailed and 135 surgeons completed the survey successfully (response rate 27%). Questions included demographics, workload, ergonomic and psychosocial factors. The relationship of these factors with WMS symptoms in the past 12 months was examined. RESULTS: Results indicated a high prevalence rate of WMS symptoms in surgeons, mainly in the neck (82.9%), low back (68.1%), shoulder (57.8%) and upper back (52.6%) regions. Sustained static and/or awkward posture was perceived as the factor most commonly associated with neck symptoms by 88.9% of respondents. Logistic regression showed the total score for physical ergonomic factors was the most significant predictor for all 4 body regions of musculoskeletal symptoms, with OR of 2.028 (95%CI 1.29-3.19) for the neck, 1.809 (1.34-2.43) for shoulder and 1.716 (1.24-2.37) for the lower back. Workstyle score was significantly associated with the symptom severity in the low back region (P = .003) but not with the other regions. CONCLUSION: These results confirmed a strong association of physical and psychosocial factors with the musculoskeletal symptoms in surgeons. There is a potential for such musculoskeletal symptoms to escalate in the future, with rapid advances and increasing application of minimally invasive surgery.

Endovascular repair for thoracic aortic pathologies--early and midterm results.

OBJECTIVE: To assess the early and midterm results of endovascular stent graft repair in patients with thoracic aortic pathologies. METHODS: Between March 2000 and December 2005, 44 consecutive patients undergoing endovascular repair for 45 thoracic aortic lesions were studied. Follow-up protocol includes regular clinical examination and computed tomographies. RESULTS: There were 37 men and 7 women with a median age of 59 years at operation (range, 26-90). The pathologies consisted of 15 thoracic aortic aneurysms, nine pseudoaneurysms, 16 thoracic aortic dissections, and five thoracic aortic injuries. Successful deployment of the endovascular stent grafts with complete sealing of the pathology were achieved in all but one patient who had the procedure abandoned as a result of access difficulty, giving a technical success of 98%. The median hospital stay was 7 days (range, 3-196), with no hospital death nor paraplegia. The median follow-up was 25 months (range, 0-86). There were eight follow-up deaths, two of which were thoracic aortic pathology related (both patients had aortoesophageal fistulae). There were three other clinical failures: distal attachment endoleak in a patient with thoracic aortic aneurysm, one enlarging and one newly developed dissecting thoracic aortic aneurysm despite endografting. The cumulative freedom from clinical failure and failure free survival were 90% and 75% at 18 months respectively. CONCLUSION: Endovascular stent graft repair is a feasible option in thoracic aortic pathologies with promising early and midterm results.

Secondary infection of a pre-existing thoracic aortic aneurysm by iatrogenic oesophageal perforation with aorta-oesophageal fistula formation.

We report a case of iatrogenic perforation of the oesophagus, with subsequent infection of a pre-existing thoracic aortic aneurysm and development of an aorto-oesophageal fistula resulting in life-threatening haemorrhage. This was successfully treated with endovascular aortic stent-graft using a Cook Zenith Tx2 device. Follow-up CT scan 3 months later showed that the aneurysm sac is getting smaller, and patient had no further septic or haemorrhagic complications. However, we emphasise that even if initial endovascular management of aorto-oesophageal fistula is successful, these patients often risk recurrent sepsis and therefore long-term clinical and radiological surveillance is mandatory.

Endovascular repair for abdominal aortic aneurysms: the first hundred cases.

OBJECTIVE: To evaluate the early and mid-term results of the first 100 elective endovascular repairs for abdominal aortic aneurysms. DESIGN: Retrospective analysis of prospectively collected data. SETTING: University teaching hospital, Hong Kong. PATIENTS: The first 100 patients with infrarenal abdominal aortic aneurysms who underwent elective endovascular repair. MAIN OUTCOME MEASURES: Peri-operative data, mortality and morbidities as well as the follow-up details were recorded. Cumulative data on endoleaks, clinical failures, secondary procedures, and survival were evaluated with Kaplan-Meier analyses. RESULTS: There were 85 men and 15 women, with a mean age of 75 (range, 50-90) years. Failed implantations due to access difficulty occurred in two patients during the same period, giving a technical success rate of 98%. The mean aneurysm diameter was 6.2 cm. Access site injury requiring repair occurred in four (4%) of the patients, while wound problems were the most common complications (11%). The median hospital stay was 6 days, and there were two hospital deaths, giving a hospital mortality rate of 2%. During a mean follow-up of 36 (standard deviation, 24) months, there were three aneurysmal ruptures and four elective open conversions, with only one aneurysm-related death after hospital discharge. At 3 years, the cumulative rates of freedom from any endoleak, freedom from primary failure, freedom from secondary failure, freedom from secondary procedures, and survival were 60%, 84%, 89%, 88%, and 78%, respectively. CONCLUSIONS: The early and mid-term results of elective endovascular repair for abdominal aortic aneurysms appear promising. The procedure is effective in preventing aneurysm-related death in the mid-term. Nevertheless, the importance of constant surveillance cannot be over-emphasised, as clinical failures and ruptures are still a concern.

A computational fluid dynamic study of stent graft remodeling after endovascular repair of thoracic aortic dissections.

OBJECTIVES: Significant stent graft remodeling commonly occurs after endovascular repair of thoracic aortic dissections because of continuing expansion of the true lumen. A suboptimal proximal landing zone, minimal oversizing, and lack of a healthy distal attachment site are unique factors affecting long-term stent graft stability. We used computational fluid dynamic techniques to analyze the biomechanical factors associated with stent graft remodeling in these patients. PATIENTS AND METHODS: A series of computational fluid dynamic models were constructed to investigate the biomechanical factors affecting the drag force on a thoracic stent graft. The resultant drag force as a net change of fluid momentum was calculated on the basis of varying three-dimensional geometry and deployment positions. A series of 12 patients with type B aortic dissections treated by thoracic stent graft and followed up for more than 12 months were then studied. Computed tomography transaxial images of each patient shortly after stent graft deployment and on subsequent follow-up were used to generate three-dimensional geometric models that were then fitted with a surface mesh. Computational fluid dynamic simulations were then performed on each stent graft model according to its geometric parameters to determine the actual change in drag force experienced by the stent graft as it remodels over time. RESULTS: The drag force on the stent graft model increases linearly with its internal diameter and becomes highest when the deployment position is closer to the proximal arch. Aortic curvature is not a significant factor. Serial computed tomography scans of patients showed an increase in mean inlet area from 1030 mm(2) to 1140 mm(2), and mean outlet area from 586 mm(2) to 884 mm(2) (increase of 11% and 58%, respectively; P = .05, .01). These increases are associated with a change in resultant drag force on the stent graft from 21.0 N to 24.8 N (mean increase, 19.5%; range, 0%-63.2%; P = .002). There is a positive relationship between increase in drag force and increase in stent-graft area. CONCLUSION: The drag force on thoracic stent grafts is high. A significant change in stent-graft diameter occurs after endovascular repair for type B dissections, which is associated with an increase in hemodynamic drag force. These stent grafts may be subjected to a higher risk of distal migration, and continuing surveillance is mandatory.

Supra-aortic hybrid endovascular procedures for complex thoracic aortic disease: single center early to midterm results.

BACKGROUND: Hybrid technique with open surgical supra-aortic extra-anatomical bypasses (to provide a suitable proximal landing zone) and simultaneous or staged thoracic endovascular stent grafting is less invasive than open surgery in the treatment of complex aortic arch pathology. The aim of this study is to report our hybrid experience. METHODS: Retrospective review of prospectively collected computerized database. All patients had regular clinical and radiological computed tomography follow-up. RESULTS: Sixteen patients (13 males and 3 females) with mean age of 64.8 (range 51-79) were treated with hybrid techniques between May 2005 and September 2007. There were nine elective, two urgent (within 2 weeks of presentation), and five emergency cases. Thirteen patients had arch or proximal descending thoracic aortic aneurysms, and six patients had aortic dissections. All extra-anatomical bypasses were performed simultaneously with stent grafts, with mean operating time of 331.2 (range 195-540) minutes. Eight patients had right to left carotid-carotid cross-over graft, five had bifurcating grafts from ascending aorta to innominate and left carotid artery, two had left carotid to left subclavian artery, and one had left carotid to aberrant right subclavian bypass graft. All patients had Cook Zenith thoracic stent grafts. Deployment success was 100%, with no endoleak on completion angiogram. There was no mortality. Three patients had postoperative nondebilitating stroke and no paraplegia. The mean follow-up was 14 (range 1-27) months. One reintervention was required, and two patients had type II endoleak treated conservatively. CONCLUSION: Supra-aortic hybrid procedures in treating aortic arch pathology are safe and effective, and early- to midterm results are encouraging.

Ionizing radiation absorption of vascular surgeons during endovascular procedures.

OBJECTIVE: Endovascular procedures have become an integral part of a vascular surgeon's practice. The exposure of surgeons to ionizing radiation and other safety issues have not been well studied. We investigated the radiation exposure of a team of vascular surgeons in an active endovascular unit and compared yearly dosages absorbed by various body parts among different surgeons. Patients' radiation exposure was also assessed. METHODS: The radiation absorption of a team of vascular surgeons was prospectively monitored in a 12-month period. During each endovascular procedure, the effective body, eye, and hand radiation doses of all participating surgeons were measured by mini-thermoluminescent dosimeters (TLD) attached at the chest level under a lead apron, at the forehead at eye level, and at the hand. The type of procedure, fluoroscopy machine, fluoroscopy time, and personal and operating theatre radiation protection devices used in each procedure were also recorded. One TLD was attached to the patient's body near the operative site to measure the patient's dose. The yearly effective body, eye, and hand dose were compared with the safety limits of radiation for occupational exposure recommended by the International Commission on Radiation Protection (ICRP). The radiation absorption of various body parts per minute of fluoroscopy was compared among different surgeons. RESULTS: A total of 149 consecutive endovascular procedures were performed, including 30 endovascular aortic repairs (EVAR), 58 arteriograms with and without embolization (AGM), and 61 percutaneous transluminal angioplasty and stent (PTA/S) procedures. The cumulative fluoroscopy time was 1132 minutes. The median yearly effective body, eye, and hand dose for the surgeons were 0.20 mSv (range, 0.13 to 0.27 mSv), 0.19 mSv (range, 0.10 to 0.33 mSv) and 0.99 mSv (0.29 to 1.84 mSv) respectively, which were well below the safety limits of the ICRP. The mean body, eye, and hand dose of the chief surgeon per procedure were highest for EVAR. A significant discrepancy was observed for the average hand dose per minute of fluoroscopy among different surgeons. The mean radiation absorption of patients who underwent EVAR, AGM, and PTA/S was 12.7 mSv, 13.6 mSv, and 3.4 mSv, respectively. CONCLUSION: With current radiation protection practice, the radiation absorbed by vascular surgeons with a high endovascular workload did not exceed the safety limits recommended by ICRP. Variations in practice, however, can result in significant discrepancy of radiation absorption between surgeons.

Cumulative risk, maternal responsiveness, and allostatic load among young adolescents.

The purpose of this study was to examine the impact of cumulative risk exposure in concert with maternal responsiveness on physiological indicators of chronic stress in children and youth. Middle-school children exposed to greater accumulated psychosocial (e.g., family turmoil, poverty) and physical (e.g., crowding, substandard housing) risk factors manifested higher levels of allostatic load, a physiological marker of cumulative wear and tear on the body caused by the mobilization of multiple, physiological response systems. This effect was longitudinal, residualizing allostatic load 3-4 years earlier when the youth were in elementary school. This effect, however, occurred only among adolescents with mothers low in responsiveness. Cumulative risk was also associated with dynamic cardiovascular processes in response to an acute stressor (mental arithmetic). Higher risk was associated with muted reactivity and slower, less efficient recovery in blood pressure. These dynamic cardiovascular effects occurred irrespective of maternal responsiveness.

Hybrid endovascular operation for ruptured thoracic aortic aneurysm.

The rupture of a thoracic aortic aneurysm is a life-threatening emergency. Conventional open surgical repair carries a high mortality and morbidity. We report an elderly patient who suffered from rupture of a proximal descending thoracic aortic aneurysm close to the aortic arch. A hybrid operation consisting of a right-to-left carotid bypass followed by endovascular repair of the descending thoracic aorta was carried out. The patient recovered uneventfully. A hybrid endovascular repair should be considered the treatment of choice for rupture of a thoracic aortic aneurysm near the arch.

Synchrony dual-optic accommodating intraocular lens. Part 1: optical and biomechanical principles and design considerations.

PURPOSE: To describe a dual-optic accommodating intraocular lens (IOL) based on theoretical considerations. SETTING: University and independent research group. METHODS: Ray-tracing analysis using optical modeling software (ZEMAXTM, Focus Software Inc., Tucson, Ariz) in a theoretical model eye was used to analyze lens configurations to optimize the accommodative and magnification effects of axial lens displacement. Finite-element modelling using a commercially available PC-based software package (COSMOS DesignSTAR) was applied to design the biomechanical parameters of the inter-optic articulations and optics. RESULTS: Ray-tracing analysis indicated that a dual-optic design with a high plus-powered front optic coupled to a minus posterior optic produced greater change in conjugation power of the eye compared to a single-optic intraocular lens and that magnification effects were unlikely to account for improved near vision. Finite-element modelling indicated that the 2 optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension. CONCLUSION: A dual-optic design linked by spring haptics increases the accommodative effect of axial optic displacement with minimal magnification effect and has promise for improving the performance of accommodative intraocular lenses.

Endovascular stent graft repair for infected thoracic aortic pseudoaneurysms--a durable option?

OBJECTIVE: Open surgical repair for infected thoracic aortic pseudoaneurysms carries significant mortality and morbidity. Endovascular stent graft repair has been our preferred approach, although its role remains controversial because persistent infection is always a concern. We aimed to assess the efficacy and durability of endovascular stent graft repair in these patients. METHODS: Between August 2000 and November 2005, seven consecutive patients with eight infected pseudoaneurysms of the thoracic aorta were treated with endovascular stent graft repair. Patients were diagnosed based on a typical appearance of an infected pseudoaneurysm on imaging together with a positive bacteriology culture or clinical evidence of sepsis. The follow-up protocol included regular clinical examination, hematologic tests, and computed tomography scans. RESULTS: There were six men and one woman with a median age of 68 years at operation. Three patients presented with an aortoenteric fistula. The operations were performed in the operating room with the image guidance of a mobile C-arm. Endovascular stent grafts were deployed successfully in all patients, with complete exclusion of the pseudoaneurysms. Intravenous antibiotics were continued for 1 to 6 weeks and followed by lifelong maintenance oral antibiotics. The median hospital stay was 27 days, with no hospital deaths. No paraplegia or other major complications occurred. Two patients with aortoesophageal fistula where the fistula tracts were persistent died during follow-up. The other five patients remained well, with no evidence of graft infection at a median follow-up of 34 months. A significant reduction in the diameter of the pseudoaneurysm (>5 mm) was noted on computed tomography scans after 12 months. CONCLUSION: Endovascular stent graft repair is effective and may be a durable option for infected pseudoaneurysms of the thoracic aorta.