bluuebunny/crossref_metadata_2025 huggingface dataset:
Phylogenetic analysis of mtDNA sequences suggests revision of humpback dolphin (Sousa spp.) taxonomy is needed
Authors: Frère Céline H. , Hale Peter T. , Porter Lindsay , Cockcroft Victor G. , Dalebout Merel L.
Published: May 2008

Humpback dolphins (Sousa spp.) have a wide distribution in the tropical Atlantic and Indo-Pacific Oceans and a confused taxonomy. Morphological assessments suggest three species groupings – Sousa teuszii (eastern Atlantic), Sousa plumbea (western Indo-Pacific), and Sousa chinensis (eastern Indo-Pacific) – but most taxonomies recognise only two species – S. chinensis (Indo-Pacific), and S. teuszii (Atlantic). To investigate phylogenetic relationships, mitochondrial DNA control region sequences (338 base pairs) from 72 Sousa representing three populations in the Indo-Pacific (South Africa: S. plumbea, n = 23; China: S. chinensis, n = 19; and Australia: S. chinensis, n = 28), and S. teuszii in the Atlantic (Mauritania, n = 2) were generated. All three Indo-Pacific populations formed robust, monophyletic clades with high bootstrap (BS) and Bayesian posterior probability (BPP) scores. Surprisingly, humpback dolphins from South Africa and China formed a strongly-supported clade with the Atlantic S. teuszii (BS 63%, BPP 0.92) to the exclusion of animals from Australia. Genetic divergence between animals from China and Australia (DA = 8.4% ± 2.47%) was greater than between China and South Africa (DA = 5.1% ± 1.80%). These results strongly suggest that Australian humpback dolphins are not S. chinensis but may represent a distinct species in their own right.
Salinity may cause fragmentation of hardyhead (Teleostei: Atherinidae) populations in the River Murray, Australia
Authors: Wedderburn Scotte D. , Walker Keith F. , Zampatti Brenton P.
Published: May 2008

Salinisation in lowland areas of the Murray–Darling Basin, Australia, has had noticeable effects on fish. The endangered endemic Murray hardyhead Craterocephalus fluviatilis is distributed patchily and confined mainly to saline waters (0.4–20 g L–1), whereas the unspecked hardyhead C. stercusmuscarum fulvus has a more continuous distribution but is absent from high salinities (>10). Osmoregulation was compared in these two congeners and an estuarine atherinid, the small-mouth hardyhead Atherinosoma microstoma, over a wide salinity range (0.03–85). All three species are euryhaline, although the osmoregulatory ability of C. s. fulvus falters above ~35 salinity. In low salinity (<1), C. fluviatilis is a better osmoregulator than A. microstoma, but both species tolerate hypersaline conditions (85). These data imply a physiological reason for the predominance of C. fluviatilis in inland saline waters, but the reasons for its absence from freshwater habitats (<0.4) remain unclear. The findings have implications for other freshwater fish, especially populations of closely related species, subjected to the effects of salinisation or other stressors.
The Role of the Extracellular Matrix in Tissue Distribution of Macromolecules in Normal and Pathological Tissues: Potential Therapeutic Consequences
Authors: Wiig Helge , Gyenge Christina , Iversen Per Ole , Gullberg Donald , Tenstad Olav
Published: May 2008

The interstitial space is a dynamic microenvironment that consists of interstitial fluid and structural molecules of the extracellular matrix, such as glycosaminoglycans (hyaluronan and proteoglycans) and collagen. Macromolecules can distribute in the interstitium only in those spaces unoccupied by structural components, a phenomenon called interstitial exclusion. The exclusion phenomenon has direct consequences for plasma volume regulation. Early studies have assigned a major role to collagen as an excluding agent that accounts for the sterical (geometrical) exclusion. More recently, it has been shown that the contribution of negatively charged glycosaminoglycans might also be significant, resulting in an additional electrostatical exclusion effect. This charge effect may be of importance for drug uptake and suggests that either the glycosaminoglycans or the net charge of macromolecular substances to be delivered may be targeted to increase the available volume and uptake of macromolecular therapeutic agents in tumor tissue. Here, we provide an overview of the structural components of the interstitium and discuss the importance the sterical and electrostatical components have on the dynamics of transcapillary fluid exchange.
Spatial Regulation of Inflammation by Human Aortic Endothelial Cells in a Linear Gradient of Shear Stress
Authors: Tsou Jean K. , Gower R. Michael , Ting Harold J. , Schaff Ulrich Y. , Insana Michael F. , Passerini Anthony G. , Simon Scott I.
Published: May 2008

Objective: Atherosclerosis is a focal disease that develops at sites of low and oscillatory shear stress in arteries. This study aimed to understand how endothelial cells sense a gradient of fluid shear stress and transduce signals that regulate membrane expression of cell adhesion molecules and monocyte recruitment. Methods: Human aortic endothelial cells were stimulated with TNF‐α and simultaneously exposed to a linear gradient of shear stress that increased from 0 to 16 dyne/cm2. Cell adhesion molecule expression and activation of NFκ B were quantified by immunofluorescence microscopy with resolution at the level of a single endothelial cell. Monocyte recruitment was imaged using custom microfluidic flow chambers. Results: VCAM‐1 and E‐selectin upregulation was greatest between 2–4 dyne/cm2 (6 and 4‐fold, respectively) and above 8 dyne/cm2 expression was suppressed below that of untreated endothelial cells. In contrast, ICAM‐1 expression and NFκ B nuclear translocation increased with shear stress up to a maximum at 9 dyne/cm2. Monocyte recruitment was most efficient in regions where E‐selectin and VCAM‐1 expression was greatest. Conclusions: We found that the endothelium can sense a change in shear stress on the order of 0.25 dyne/cm2 over a length of ∼ 10 cells, regulating the level of protein transcription, cellular adhesion molecule expression, and leukocyte recruitment during inflammation.
Cdc14B depletion leads to centriole amplification, and its overexpression prevents unscheduled centriole duplication
Authors: Wu Jun , Cho Hyekyung P. , Rhee David B. , Johnson Dabney K. , Dunlap John , Liu Yie , Wang Yisong
Published: May 2008

Centrosome duplication is tightly controlled in coordination with DNA replication. The molecular mechanism of centrosome duplication remains unclear. Previous studies found that a fraction of human proline-directed phosphatase Cdc14B associates with centrosomes. However, Cdc14B's involvement in centrosome cycle control has never been explored. Here, we show that depletion of Cdc14B by RNA interference leads to centriole amplification in both HeLa and normal human fibroblast BJ and MRC-5 cells. Induction of Cdc14B expression through a regulatable promoter significantly attenuates centriole amplification in prolonged S phase–arrested cells and proteasome inhibitor Z-L3VS–treated cells. This inhibitory function requires centriole-associated Cdc14B catalytic activity. Together, these results suggest a potential function for Cdc14B phosphatase in maintaining the fidelity of centrosome duplication cycle.
Pitx2 is functionally important in the early stages of vascular smooth muscle cell differentiation
Authors: Shang Yueting , Yoshida Tadashi , Amendt Brad A. , Martin James F. , Owens Gary K.
Published: May 2008

Mechanisms that control vascular smooth muscle cell (SMC) differentiation are poorly understood. We identify Pitx2 as a previously unknown homeodomain transcription factor that is rapidly induced in an in vitro model of SMC differentiation from multipotent stem cells. Pitx2 induces expression of multiple SMC differentiation marker genes by binding to a TAATC(C/T) cis-element, by interacting with serum response factor, and by increasing histone acetylation levels within the promoters of SMC differentiation marker genes. Suppression of Pitx2 reduces expression of SMC differentiation marker genes in the early stages of SMC differentiation in vitro, whereas Prx1, another homeodomain protein, regulates SMC differentiation marker genes in fully differentiated SMCs. Pitx2, but not Prx1, knockout mouse embryos exhibit impaired induction of SMC differentiation markers in the dorsal aorta and branchial arch arteries. Our results demonstrate that Pitx2 functions to regulate the early stages of SMC differentiation.
Endoscopic Vascular Harvest in Coronary Artery Bypass Grafting Surgery: A Meta-Analysis of Randomized Trials and Controlled Trials
Authors: Cheng Davy , Allen Keith , Cohn William , Connolly Mark , Edgerton James , Falk Volkmar , Martin Janet , Ohtsuka Toshiya , Vitali Richard
Published: May 2008

Objective

This meta-analysis sought to determine whether endoscopic vascular graft harvesting (EVH) improves clinical and resource outcomes compared with conventional open graft harvesting (OVH) in adults undergoing coronary artery bypass surgery.

Methods

A comprehensive search was undertaken to identify all randomized and nonrandomized trials of EVH versus OVH up to April 2005. The primary outcome was wound complications. Secondary outcomes included any other clinical morbidity and resource utilization. Odds ratios (OR), weighted mean differences (WMD), or standardized mean differences (SMD) and their 95% confidence intervals (95% CI) were analyzed.

Results

Thirty-six trials of 9,632 patients undergoing saphenous vein harvest met the inclusion criteria (13 randomized; 23 nonrandomized). Risk of wound complications was significantly reduced by EVH compared with OVH (OR 0.31, 95% CI 0.23–0.41). Similarly, the risk of wound infections was significantly reduced (OR 0.23, 95% CI 0.20–0.53; P < 0.0001). Need for surgical wound intervention was also significantly reduced (OR 0.16, 95% CI 0.08–0.29). The incidence of pain, neuralgia, and patient satisfaction was improved with EVH compared with OVH. Postoperative myocardial infarction, stroke, reintervention for ischemia or angina recurrence, and mortality were not significantly different. Operative time was significantly increased (WMD 15.26 minutes; 95% CI 0.01, 30.51), hospital length of stay was reduced (WMD −0.85 days; 95% CI −1.55, −0.15), and readmissions were reduced (OR 0.53, 95% CI 0.29–0.98). Costs were insufficiently reported to allow for aggregate analysis.

Conclusions

Endoscopic vascular graft harvesting of the saphenous vein reduces wound complications and improves patient satisfaction and resource utilization. Further research is required to determine the incremental cost-effectiveness of EVH versus OVH.
Proposal for a Novel Concept of a Hybrid, Minimally Invasive Cardiovascular Surgical Practice
Authors: Sherif Hisham M.F.
Published: May 2008

Background

Due to the increase in new Interventional cardiovascular technologies, traditional lines of division between the interventional and surgical aspects are expected to blur, with these procedures modified and adopted into cardiovascular surgical practice. This proposal introduces new concepts and visions for such new devices and procedures.

Methods

I-Precision Planning II-Examples of Proposed Devices III-Examples of Proposed Procedures

Results

Over the past few years there has been a growing sense of anxiety about new interventional devices in the cardiovascular surgical community. As physicians, our main task is to formulate simpler, more effective and safer solutions to clinical problems; and as surgeons, we “devise mechanical solutions to clinical problems.”

Conclusions

Nowadays, there is an urgent need for the cardiovascular surgical community to rediscover and reinvent itself. We should see these new innovations as exciting new ideas and tools that we can “modify, simplify and apply” to revitalize our own practice.
Computer-Mediated Power Stapling for Anatomical Lung Resection: Experience in 100 Consecutive Cases
Authors: Vigneswaran Wickii T. , Gruner Charles
Published: May 2008

Objectives

Mechanical stapling is widely used for lung resection. Complications related to the stapling are few but not infrequent. This varies from complete disruption of the staples to incomplete sealing of vascular structures. A stapling platform that has a strong clamping force with precise and consistent staple formation suitable for thickness of tissue is likely to be an advance in existing devices and may reduce the complication rate. A new, computer-mediated power stapling is currently available for lung resections, with three types of digital loading units (DLU). Clinical data on its use are limited. We report our experience with this stapling platform (SurgASSIST) in our first 100 patients undergoing anatomic lung resection.

Methods

Fifty-four men and forty-six women (mean age, 64 ± 7 years) underwent anatomic lung resections, using a lateral, muscle-sparing mini-thoracotomy, during 2004 to 2005, with the SurgASSIST platform. Three types of DLUs were used for lung resection: a linear cutter, a right-angled vascular cutter, and a right-angled bronchial cutter. Observational data were collected prospectively on the operative procedure, type of staples used, duration of operation, chest tube drainage, and hospital length of stay.

Results

There were 83 lobectomies, 5 bilobectomies, 5 segmental resections, and 7 pneumonectomies. A total of 502 DLUs (mean, 5 per patient; 102 vascular, 91 bronchial, and 309 linear cutters) were used in this series. There were no major operative complications. The mean operating time was 136 ± 41 minutes. One bronchial dehiscence and one incomplete sealing of the pulmonary vein in the staple line were observed. In one patient, the linear cutter could not be opened in the automatic setting. There were 15% misreads by the computer on the DLU or their inserts. There was one hospital death unrelated to the stapling. Twenty additional complications included prolonged chest tube drainage (n = 8), reoperations (n = 2), atrial fibrillation (n = 5), hemothorax (n = 1), chylothorax (n = 1), C-dif colitis (n = 1), myocardial ischemia (n = 1), and incarcerated ventral hernia (n = 1). The median hospital length of stay was 5 days (range, 3 to 26 days) and the median length of chest tube drainage was 3 days (1 to 22 days).

Conclusions

Our experience shows that the computer-mediated power stapling of lung parenchyma and hilar structures during anatomic resection is safe and reproducible.
Use of the Navigator Probe after Radiotracer Injection to Identify Nonpalpable Rib Lesions Requiring Surgical Resection
Authors: Erdem Can Caglar , Daly Benedict , Ketchedjian Ara , Stone Michael , Shemin Richard , Shah Nirav P. , Fernando Hiran
Published: May 2008

Background

Patients with nonpalpable rib lesions (NPRL) requiring biopsy present a challenging problem for the thoracic surgeon. Ideally, a small incision directly over the NPRL should be performed to minimize morbidity, particularly if the lesion is benign. The Navigator probe is routinely used after lymphoscintigraphy by surgical oncologists to isolate sentinel lymph nodes requiring removal, but can also be used to guide resection of nonpalpable focal rib lesions demonstrating increased technetium-99m hydroxymethylene diphosphonate (Tc-99m HDP) uptake. This report describes our initial experience with this technique.

Methods

Over a 5-month period, 3 patients with focal NPRL underwent rib resection. All patients had solitary lesions demonstrated on recently performed Tc-99m HDP bone scanning. Prior cancers were reported in 2 patients, and pain in 2 patients. Before surgery, all patients underwent intravenous injection of 20 to 25 mCi Tc-99m HDP at least 2 hours before the Navigator probe-guided procedure.

Results

The Navigator probe identified all 3 lesions, allowing a single 4 cm or smaller incision in all cases. Histology included metastatic breast cancer (1), pathologic fracture secondary to metastatic palatal cancer (1), and eosinophilic granuloma (1). No patient required further resection.

Conclusions

Intraoperative localization of NPRL that are positive on Tc-99m HDP bone scanning using the Navigator probe is feasible and was 100% successful in our initial experience. This technique allows a minimally invasive approach, which is beneficial for those patients who do not require further resection.
Thoracoscopic Approach to Epicardial Lead Implantation in Adult Patients with Previous Congenital Cardiac Surgery
Authors: Vassiliades Thomas A. , McConnell Michael E. , Book Wendy M.
Published: May 2008

Background

Substantial technical challenges exist in placing transvenous pacing leads in the heterogeneous adult congenital heart disease patient population. Anatomical issues including occlusion of central veins, single ventricle physiology, and lack of transvenous access to systemic right ventricles, often require thoracotomy for epicardial lead placement.

Methods

We assessed the feasibility of performing a totally thoracoscopic approach to epicardial pacing lead implantation in 10 adult patients (mean age 32.5 years) with congenital heart disease. The underlying cardiac anatomy consisted of transposition of the great arteries, status post (s/p) Mustard procedure (3); tricuspid atresia, s/p Fontan procedure (3); congenitally corrected transposition (1); Ebstein's anomaly, s/p tricuspid valve replacement (1); AV canal, s/p repair (1); and hypertrophic cardiomyopathy, s/p myomectomy (1). Twenty-six previous cardiac operations (mean 2.8 per patient) had been performed in this group.

Results

Indications for thoracoscopic lead insertion included primary rhythm disturbances, progressive heart failure with a QRS>120 milliseconds, and an unapproachable coronary sinus or failed transvenous lead insertion. All patients underwent thoracoscopic implantation of 2 epicardial leads to the systemic ventricle and generator insertion. Intraoperative transesophageal echocardiography (TEE) was used in all cases, which facilitated port placement. Measurements at operation showed mean threshold of 2.0V (95% CI 0.9–3.1V at 0.5 milliseconds) and a mean impedance of 1259 Ohms (95% CI 418–2100). There were no procedural related complications and no patient required conversion to an open procedure. Seventy percent of patients were extubated immediately after the procedure and were discharged from the intensive care unit within 24 hours. There was 1 noncardiac death due to gastrointestinal ischemia.

Conclusion

Adults with congenital heart disease present significant challenges to pacing lead implantation including variability of the location of the systemic ventricle, coronary sinus anatomy, right-sided valve replacement, a small thoracic cavity, limited vascular access, and adhesions from prior cardiac procedures. Additionally, thoracoscopy has been previously considered a contraindication in this subgroup of patients. However, we have demonstrated that with careful preoperative planning and the assistance of TEE, a totally thoracoscopic approach to epicardial lead implantation is both feasible and safe.
Robotic Mitral Valve Repairs Requiring Reoperations
Authors: Rodriguez Evelio , Chu Michael W. A. , Narron John , Gersch Karen , Nifong L. Wiley , Chitwood W. Randolph
Published: May 2008

Objective

Robotic mitral valve (MV) repairs are performed at many institutions. Repair failures have been attributed to the challenging technology and potentially to the use of annuloplasty band anchoring U-clips. The purpose of this study was to characterize causes of robotic MV repair failure.

Methods

A total of 300 patients underwent a da Vinci robotic MV repair between May 2000 and November 2006 by a single operating console surgeon. Standard repair techniques and a Cosgrove annuloplasty band were used in every case. Clinical data in patients requiring a reoperation, as well as videos of their original operation, were reviewed. MV pathology, repair methods, and findings at reoperation were determined.

Results

Sixteen (5.3%) patients required reoperation. Seven (7%) failures occurred in the first 100 cases and 9 (4.5%) in the last 200 cases. Initial MV pathology included isolated anterior (n = 4) or posterior leaflet prolapse (n = 6), bileaflet prolapse (n = 3), and annular dilation (n = 3). Reoperations after their initial operation were required early (<6 months) in 8 patients and later in 8 patients. Reasons for reoperation included CHF (n = 9), hemolysis (n = 4), systolic anterior leaflet motion (n = 2), and endocarditis (n = 1). At reoperation, 7 patients had partial dehiscence of the annuloplasty band. The incidence of band dehiscence was not associated with the use of U-clips and decreased with experience.

Conclusions

Reoperative rates seemed to decrease with increased case volume and surgeon's experience. Repair results using robotic techniques are similar to conventional techniques. The use of U-clips is not associated with a higher reoperation rate.
The Use of the Mini-Cardiopulmonary Bypass Circuit in Robotic Mitral Valve Surgery
Authors: Emery Robert W. , Raikar Goya V. , Murphy Barbara , Rohan Anton , Nielsen Kris
Published: May 2008

Background

Computer enabled robotic mitral valve repair cases have longer cross-clamp and perfusion times because of the more technically difficult procedure. To modify some of the well-documented side effects of standard cardiopulmonary bypass (CPB), we used a new mini-circuit on three robotic mitral cases.

Methods

Three patients having mitral valve repair (triangular resection of P2 and annuloplasty ring) using the daVinci Robot (Intuitive Surgical, Sunnyvale, CA) had circulatory support using a modified Resting Heart System (Medtronic, Inc., Fridley, MN), a vertically oriented space saving CPB configuration incorporating a high efficiency miniaturized oxygenator, centrifugal pump, shortened heparin coated tubing and an air evacuation system with a closed circuit.

Results

All patients had successful mitral repair (echo = 0 to trace residual leakage) under a cross-clamp time of 161 ± 54 minutes and perfusion time of 229 ± 31 minutes. No blood was given during CPB and 0.7 ± 1.2 red cell units after the CPB run and 0.7 ± 1.2 units during the postoperative course.

Conclusion

Miniaturized bypass circuit reducing the level of necessary anticoagulation, hemodilation, and blood trauma can be used despite the increased perfusion time necessary for robotic mitral surgery.
Epicardial Atrial Ablation Using a Novel Articulated Robotic Medical Probe via a Percutaneous Subxiphoid Approach
Authors: Ota Takeyoshi , Degani Amir , Zubiate Brett , Wolf Alon , Choset Howie , Schwartzman David , Zenati Marco A.
Published: May 2008

Objective

Minimally invasive epicardial atrial ablation to cure atrial fibrillation through the use of a percutaneous subxiphoid approach currently has a lack of dedicated technology for intrapericardial navigation around the beating heart. We have developed a novel articulated robotic medical probe and performed preliminary experiments in a porcine preparation.

Methods

In five large, healthy pigs, the teleoperated robotic system was introduced inside the pericardial space through a percutaneous subxiphoid approach. Secondary visualization of the left atrium and left atrial appendage was achieved with the use of a 5-mm scope inserted through a left thoracic port. The operator actively controlled the path of the robot by using a master manipulator. The catheter, with an irrigated radiofrequency tip, was guided through the working port of the robot to achieve epicardial ablation of the left atrium.

Results

Access to the pericardial space and progression around the left atrium was successful in all cases, with no interference with the beating heart such as a fatal arrhythmia, unexpected bleeding, and hypotension. Epicardial ablation was successfully performed in all five cases. No adverse hemodynamic or electrophysiological events were noted during the trials. When the animals were killed, there was no visually detected injury on the surrounding mediastinal structures caused by ablation. Transmural ablation was confirmed by histopathology of the left atrium.

Conclusions

We have developed a dedicated articulated robotic medical probe and successfully performed epicardial left atrial radiofrequency ablation. Based on the feedback from these preliminary experiments, the radius of curvature and proper visualization of the device are being improved in the next generation prototype.
Use of Peripheral Ultrafiltration in the Postoperative Cardiac Surgery Patient
Authors: Emery Robert W. , Hommerding Jan , Emery Ann M. , Holter Arlen R. , Raikar Goya V.
Published: May 2008

Background

After cardiac surgery, most patients have development of third-space fluid retention, commonly treated with diuretics. In some patients diuretics are ineffective. In this subset, a simplified system for ultrafiltration was used for fluid extraction.

Methods

After obtaining permission from the institutional review board, the hospital charts of the first 30 patients having ultrafiltration were retrospectively reviewed to abstract data on fluid extraction and patient outcomes. Data are expressed as mean ± standard deviation.

Results

From April 2004 through January 2006, 30 patients were selected for ultrafiltration. In one patient, adequate intravenous access could not be obtained. There were 11 female and 18 male (age, 69 ± 12 years) postoperative cardiac surgery patients. The mean ultrafiltration run was 10.5 ± 9 hours, resulting in fluid extraction of 3528 ± 2111 mL per run and 5596 ± 3870 mL per patient (11 patients had more than 1 run). Hospital stay was 9.4 ± 4.4 days. Three patients died unrelated to ultrafiltration.

Conclusions

Ultrafiltration as an alternative means of fluid extraction in postoperative cardiac surgery patients was effective and well tolerated.
Can Surgeons Do Complete Revascularization in Diabetic Patients Using the Off-Pump Technique?
Authors: Arom Kitipan V. , Jotisakulratana Vibul , Pitiguagool Vitoon , Banyatpiyaphod Sujit , Asawapiyanond Sawat , Pamornsing Piyapan , Suwannakijboriharn Chokchai , Ruengsakulrach Permyos
Published: May 2008

Background

The arguments are discussed as to whether or not to proceed with multivessel percutaneous coronary intervention, with or without a drug-eluting stent, in patients with diabetes mellitus (DM), including (1) surgeons unable to complete revascularization because of smaller native arteries; and (2) diabetic patients being sicker and having higher operative mortality rates than nondiabetic patients (non-DM), particularly with the conventional coronary artery bypass surgery (on-pump) technique. To support or dispute the claims, a retrospective review of 480 consecutive patients at a single institution (195 DM and 285 non-DM) was carried out. Observations were made to see whether diabetes is a predictor of poor outcomes.

Materials and Methods

The preoperative comorbidity, intraoperative measurement of the size of the artery at the site of anastomosis with different gauged probes, and the number of grafts per patient were recorded. Intraoperative and postoperative variables between two groups were compared. The observed number of grafts (O) after surgery was compared with the number of grafts predicted (P) before surgery. The O/P ratio or “completion index” of ≥1 signifies complete revascularization. Logistic regression analysis was used to test the possibility that diabetes is a predictor of poor outcomes.

Results

Diabetic patients were older, with more comorbidity (congestive heart failure, peripheral vascular diseases, dialysis-dependent). The number of grafts per patient was 4.2 ± 1.3 (DM) and 4.2 ± 1.3 (non-DM). The size of 742 DM and 949 non-DM arteries were gauged. There was no statistical difference in size between DM and non-DM (in millimeters) at each artery. All ratios ranged from 0.9 to 1.2, indicating similarity between DM and non-DM. The only significant risk factor for operative death was low left ventricular ejection fraction (P = 0.001).

Conclusions

Patients with DM were sicker but tolerated off-pump coronary artery bypass grafting as well as non-DM patients. The number of grafts per patient and O/P ratio signify the ability to perform complete revascularization. We are able to bypass the small target vessels, as anticipated. Diabetes is not a predictor of the outcomes.
Technical Innovations in the Minimally Invasive Approach for Treating Pectus Excavatum: A Paradigm Shift through Six Years’ Experience with 630 Patients
Authors: Park Hyung Joo
Published: May 2008

Objective

The multiple-momentum (MM) based multitarget (MT) approach has been developed through a single surgeon's experience to overcome the limits of the conventional Nuss procedure, which is the single target-single momentum approach that corrects only symmetric pectus excavatum (PE). The new techniques that have been devised on a morphologic basis, according to the Terrain Contour Matching (TERCOM) system, have made this approach a comprehensive one that can cover all types of pectus deformity. The aim of this study was to elucidate the difference between the conventional technique and the new approach.

Methods

The data of 630 PE patients who received the modified Nuss procedure, based on the MM-MT-TERCOM approach, between 1999 and 2005, were retrospectively studied. The conceptual differences between the new approach and the conventional one were determined. The techniques according to a new paradigm, for treating asymmetry, adults, and complex morphology, as well as the bar fixation technique, were analyzed. The results of the repair were assessed with a new CT index, the Asymmetry Index (AI).

Results

According to the morphologic classification, 269 patients were asymmetric (42.7%): 138 were eccentric (53 Grand Canyon type), 88 were unbalanced, and 36 were combined. On the basis of the MM-MT-TERCOM concept for repairing complex morphology, multiple targets were selected in 224 patients (35.6%). To correct targets simultaneously, positive momentum (630 patients, 100%) and negative momentum (124 patients, 19.7%) were applied as appropriate. The techniques used were an asymmetric bar (250 patients, 39.7%), a seagull bar (107 patients, 17%), a complex bar via TERCOM (126 patients, 20%), the crest compression technique (59 patients, 9.4%), and a compound bar (84 patients, 13.3%). The postoperative changes of the AI were from 1.03 ± 0.06 to 1.02 ± 0.13 (P = 0.117) in the symmetric group and they were from 1.1 ± 0.05 to 1.02 ± 0.02 (P < 0.001) in the asymmetric group.

Conclusions

Refinement of techniques in accordance with the morphology and cause-effect basis of the bar action provided reproducible results for achieving postrepair symmetry for treating complex PE. Therefore, the new approach with techniques that use multiple momentums (MM-MT-TERCOM) supports the new paradigm of the Nuss procedure is effective in repair of all morphologic types of PE.
Wide Variations in Energy Delivery Using an Impedance-Controlled Algorithm in Bipolar Radiofrequency Ablation: Evidence against Fixed Time Ablation
Authors: Melby Spencer J. , Zierer Andreas , Voeller Rochus K. , Lall Shelly C. , Bailey Marci S. , Moon Marc R. , Schuessler Richard B. , Damiano Ralph J.
Published: May 2008

Objective

Bipolar radiofrequency ablation recently has been used to replace many of the incisions of the Cox-Maze procedure in the surgical treatment of atrial fibrillation. The unique aspect of this technology is that it uses an algorithm based on changes in tissue conductance to determine the energy required to achieve a transmural lesion instead of relying on predetermined time and/or temperature criteria to determine ablation duration, as with most other ablation technologies. The purpose of this study was to determine variations in the different parameters of ablation needed to create transmural lesions in human atria.

Methods

Initial impedance, total energy, temperature, and ablation time were measured in 38 patients undergoing surgery, using an impedance-controlled bipolar radiofrequency device (AtriCure Isolator, Cincinnati, OH). Lesions were categorized into the following groups: right atrial free wall, left atrial free wall, atrium up to mitral valve annulus, atrium up to tricuspid valve annulus, and right or left pulmonary veins.

Results

There was a wide range of initial impedance (32.3 to 760.7 Ohms), and this correlated with total energy delivered (r = −0.31, P = 0.002). Ablation times varied widely (2.0 to 29.9 seconds) and were longer on left atrial structures than right (P < 0.005) and shortest near the tricuspid annulus (P < 0.001). Mean tissue temperature 1 mm from the electrode was only 45.7 ± 7.8°C (range, 23.7°C to 69.3°C).

Conclusions

Bipolar ablation of different atrial structures required widely different amounts of energy and ablation times, probably as the result of the inhomogeneity of atrial geometry and tissue impedance. These data cast doubt on the efficacy of any fixed-time or temperature ablations in the clinical setting.
Beating Heart Direct Left Atrial Access Balloon Cryoablation: Safety and Efficacy of Pulmonary Vein Isolation in an Ovine Model
Authors: Gammie James S. , Yankey G Kwame , Nolan Timothy , Wu Z. Jon , Dickfeld Timm , Cartier Catherine , Tremblay Andre , MacNeil Timothy P. , Burke Allen , Griffith Bartley P.
Published: May 2008

Objective

Clinical experience with endocardial cryoablation for the surgical treatment of atrial fibrillation has demonstrated safety and efficacy. Direct access to the left atrium via a thoracoscopic or pericardial approach with a balloon-tipped cryoablation catheter might facilitate endocardial cryoablation on the beating heart. We investigated the ability of a novel cryoballoon to produce endocardial pulmonary vein ostial cryolesions on the beating heart in a large-animal model.

Methods

Six sheep underwent small left thoracotomy. A 10.5F catheter with a 23-mm cryoballoon was inserted directly into the left atrium under fluoroscopic and intracardiac echo (ICE) guidance. Cryoablation of the pulmonary vein ostia was performed. Animals were killed at 14 days. Pulmonary venous electrical isolation was assessed immediately before the animals were killed.

Results

All animals survived balloon cryoablation with no periprocedural complications. Balloon occlusion was well tolerated hemodynamically, with minimal change in blood pressure (–4 ± 6 mm Hg systolic BP) and no change in heart rate. ICE demonstrated an absence of intracardiac air or ice embolization during ablation. Mean balloon temperature was −67 ± 8°C. All animals were neurologically intact after the procedure. Five of 6 (83%) veins exhibited circumferential exit block. Phrenic nerve function was intact in all animals. On gross inspection, all lesions were circumferential and continuous without evidence of endocardial thrombus. Pathology confirmed circumferential transmurality in all treated veins.

Conclusions

Direct left atrial access cryoballoon ablation was effective for isolating pulmonary veins. This technology may be an important component of a minimally invasive beating heart CryoMaze procedure for the treatment of atrial fibrillation.
Robotic-Assisted Lung Resection for Malignant Disease
Authors: Anderson Casandra A. , Hellan Minia , Falebella Andres , Lau Clayton S. , Grannis Fredric W. , Kernstine Kemp H.
Published: May 2008

Objective

There have been few reports of the use of robotic surgery to resect lung malignancies. Feasibility and safety of robotic lung resection for malignant lung lesions will be assessed by performing a retrospective analysis.

Methods

Between September 2004 and November 2006, 21 patients (11 male and 10 female patients) underwent robotic lung resection. Twenty resections were performed for primary nonsmall cell lung cancer and two for metastatic lesions. One patient had bilateral resections for two primary tumors. Fourteen lobectomies, five segementectomies, one wedge resection, and two bilobectomies were performed. Seventy-two percent of operative procedures included mediastinoscopy and/or bronchoscopy at the time of resection.

Results

Thirty-day mortality and conversion rate was 0%. The median operating room time and estimated blood loss was 3.6 hours and 100 mL, respectively. The median intensive care unit and total length of hospital stays were 2 and 4 days, respectively. Chest tubes were removed after a median of 2.0 days. The complication rate was 27%, which included atrial fibrillation, need for postoperative bronchoscopy, and pneumonia. The median tumor size and number of lymph nodes harvested was 2.3 cm and 16, respectively. All resection margins were negative. Median follow-up time was 9.8 months, with no local recurrences at this time.

Conclusion

Robotic lung resection appears safe and feasible and allows for significant lymph node retrieval, offers short hospital stays and low morbidity for patients undergoing surgical resection of lung malignancies. Future studies are needed to define the role of robotic surgery in lung cancer treatment.
Intraoperative in Situ Radial Artery Conduit Flow Assessment
Authors: Canver Charles C. , Yousafzai Sajjad M.
Published: May 2008

A technique is described for simple flow assessment of the in situ radial artery conduit during coronary bypass via a small incision. This technique allows morphologic and physiologic direct intraoperative assessment of radial artery quality and expands the use of radial artery during coronary artery surgery.
Efficacy of Intramyocardial Injection of Angiogenic Cell Precursors for Ischemic Cardiomyopathy
Authors: Arom Kitipan V. , Ruengsakulrach Permyos , Jotisakulratana Vibul
Published: May 2008

Introduction

The objective of this study is to determine the efficacy of intramyocardial angiogenic cell precursors (ACPs) injection in ischemic cardiomyopathy (ICM).

Methods

Twenty-five ICM patients (cell group) underwent intramyocardial ACPs injection. Seventeen ICM patients (control group) treated by medical means were matched with cell group. There was no statistically significant difference between cell and control groups in relation to left ventricular ejection fraction (LVEF) and comorbidities. In the cell group, mean age was 58.4 ± 13.7 years. Mean LVEF was 26.1% ± 7.4%. New York Heart Association (NYHA) class was 2.9 ± 0.6. The ACPs were derived and expanded from autologous blood. The number of cells before injection was 27.4 ± 18.8 million cells. The cells were injected into the nonviable myocardium and hypokinetic segments in the cell group.

Results

There was no new ventricular arrhythmia. NYHA was improved by 0.9 ± 1.0 (P < 0.001) at 229.9 ± 98.8 days. Six-minute walk test and quality of life assessed by short form-36 improved in the cell group. LVEF was improved in 72% of patients (18 of 25). LVEF improved by 6.4 ± 9.9 points % (P = 0.003) at 290.4 ± 210.3 days. The percentage of infarction area decreased 21.9 ± 17.4 points % at 159 ± 54 days postoperatively. There was no significant improvement of NYHA and LVEF in the control group.

Conclusions

For this efficacy study, the NYHA class, quality of life, and six-minute walk test were improved after cell transplantation. The LVEF was also significantly improved in the cell treated group.
Tension Measurement of Artificial Chordae Tendinae Implanted between the Anterior Mitral Valve Leaflet and the Left Ventricular Apex
Authors: Bajona Pietro , Zehr Kenton J. , Liao Jun , Speziali Giovanni
Published: May 2008

Objective

A newly developed surgical technique allows implantation of artificial chordae tendinae between a mitral valve leaflet and the left ventricular (LV) apex in a closed-chest, off-pump mitral valve repair operation. However, this orientation causes tension vectors on the mitral valve leaflet in a different direction than those of native chordae. The purpose of this study was to investigate the relationship between systolic LV pressure and the tension of artificial chordae secured at the ventricular apex to assess if the altered tension vectors on the mitral leaflet resulted in excessive stress on the chordae/leaflet system.

Methods

Freshly harvested porcine mitral valves were suspended in a mechanical LV simulator. Two 5-0 Gore-Tex sutures were secured to the free edge of the middle scallop of the anterior leaflet adjacent to the insertion point of two major native chordae. The native chordae were then cut. A simulator pump was activated at different pressure levels, and the tension of the artificial chordae was measured with a digital tensiometer during several cardiac cycles.

Results

The numerical relationship between chordal tension (in Newtons, N) and LV pressure (in mm Hg/100) averaged at 0.8 (range 0.6–1.05). This tension/pressure relationship was similar in order of magnitude and range to that measured in native chordae in previously published studies.

Conclusions

In this in vitro model, orienting artificial chordae in a direction mimicking implantation between the valve and the LV apex does not result in excessive tension stress on either the chordae or the mitral leaflet.
TDI Based Automotive Seating: Solutions for Enhancing Foam Durability
Authors: van Eetvelde Els , Banner Carol , Cenens Jos , Chin Steven
Published: May 2008

Improving the comfort and durability properties of automotive seating is an increasingly important issue within the global automotive seating industry. The technology for enhancing the comfort properties of polyurethane foams is one of the major needs of seating foam manufacturers and seat producers, whose focus is both foam density reduction and overall weight reduction of car seats. Shell Chemicals has therefore embarked on a fundamental program, focusing on the foam formulation durability relation of TDI-based foam grades.

The study consists of a thorough investigation of the influence of independent formulation variables such as raw materials composition, water level and ancillary chemicals levels on foam processing and durability performance. A statistics driven experimental approach (central composite and full factorial designs) helped to increase the predictive power of the outcome, concerning overall mechanical foam properties and comfort performance in particular.
HFC-365mfc Blends: Status and Development as Blowing Agent for High Performance Insulation Foams
Authors: Zipfel Lothar , Dournel Pierre
Published: May 2008

The recent developments confirm that HFC-365mfc is a very attractive blowing agent option, especially if we consider the various blends which have been developed to meet customers needs, for example non-flammability in a blend withHFC-134a or k-value improvement for hydrocarbon blown foams.

The non-flammable blend HFC-365mfc/134a is an option for the construction market, notably for systems, for spray and for pour-in-place foams and is a direct replacement for HCFC-141b; as this blend is a mixture, there is an important difference compared to HCFC-141b. The special behavior during storage and handling will be explained, including details regarding its safety status.We will report our experience for a safe application and about new results in foams.

For cost-drive markets, where explosively flammable options are acceptable, blends of HFC-365mfc with hydrocarbons are an attractive way to improve the k-value of foams. This paper will report the outstanding versatility of HFC-365mfc to provide the construction foam industry with a solution for all markets. The full commercialization of HFC-365mfc is scheduled for the end of the year 2002.
Effects of interaction design in digital libraries on user interactions
Authors: Zhang Xiangmin , Li Yuelin , Liu Jingjing , Zhang Ying
Published: May 2008

Purpose

This study aims to investigate the effects of different search and browse features in digital libraries (DLs) on task interactions, and what features would lead to poor user experience.

Design/methodology/approach

Three operational DLs: ACM, IEEE CS, and IEEE Xplore are used in this study. These three DLs present different features in their search and browsing designs. Two information‐seeking tasks are constructed: one search task and one browsing task. An experiment was conducted in a usability laboratory. Data from 35 participants are collected on a set of measures for user interactions.

Findings

The results demonstrate significant differences in many aspects of the user interactions between the three DLs. For both search and browse designs, the features that lead to poor user interactions are identified.

Research limitations/implications

User interactions are affected by specific design features in DLs. Some of the design features may lead to poor user performance and should be improved. The study was limited mainly in the variety and the number of tasks used.

Originality/value

The study provided empirical evidence to the effects of interaction design features in DLs on user interactions and performance. The results contribute to our knowledge about DL designs in general and about the three operational DLs in particular.
Leaders as facilitators of individual and organizational learning
Authors: Amy Amy H.
Published: May 2008

Purpose

The organizational learning and learning organization literatures lack empirical support in delineating the role leaders play in fostering or hindering learning. This study aims to build upon previous research on facilitative leadership in learning organizations to consider how leaders contribute to and detract from learning at the individual and organizational levels in the corporate context.

Design/methodology/approach

Preliminary survey research confirmed that the Fortune 500 company being considered for the study was perceived as a learning organization by its employees. The study then proceeded with critical incident interviews with managers and their direct reports, resulting in a cross‐case content analysis of four categories: triggers, beliefs, behaviors, and outcomes, which prompted the development of a preliminary model of the learning process depicted by participants.

Findings

The findings revealed that learning leaders have several distinct characteristics and skills, but the participants gave the most emphasis to emotionally intelligent communication, a prominent feature of facilitative leadership.

Research implications/limitations

The study represents the perceptions of participants within a particular context at a specific time. Future research could include longitudinal, cross‐cultural studies that focus on communication processes related to learning.

Practical implications

The study confirmed the importance of facilitative leadership while highlighting both cognitive and emotional aspects of learning. It also pinpointed mechanisms for institutionalizing learning.

Originality/value

The study offers empirical support for the centrality of facilitative leadership while pinpointing communication competence and emotional intelligence as essential aspects of effective learning leadership.