The Effect of Chief Executive Officer and Board Prior Corporate Social Responsibility Experiences on Their Focal Firm's Corporate Social Responsibility: The Moderating Effect of Chief Executive Officer Overconfidence.

This research aims to examine how the prior experiences of the chief executive officer (CEO) and board influence the focal firm's Corporate Social Responsibility (CSR) activities. Further, the present study examines how CEO overconfidence influences the diffusion of CSR activities. The authors theorize that overconfident CEOs are influenced more by the corporate strategies they experienced on other boards and less by the corporate strategies experienced by other directors. Through longitudinal analyses of the CSR profiles a sample of S&P 500 companies for the period 2006-2013, the study shows that CEO and board prior CSR experience are positively related to the firm's current CSR activities. The authors find a significant positive moderating effect of CEO overconfidence on the relationship between CEO prior CSR and the focal firm's CSR. The theory and results highlight how CEO and board prior CSR exposure may influence the focal firm's stances toward CSR and that CEO overconfidence may have differential effects on these relationships.

Modulation of experimental autoimmune encephalomyelitis through colonisation of the gut with Escherichia coli.

Multiple sclerosis (MS) is a neuro-inflammatory autoimmune disease of the central nervous system (CNS) that affects young adults. It is characterised by the development of demyelinating lesions and inflammation within the CNS. Although the causes of MS are still elusive, recent work using patient samples and experimental animal models has demonstrated a strong relationship between the gut microbiota and its contribution to CNS inflammation and MS. While there is no cure for MS, alteration of the gut microbiota composition through the use of probiotics is a very promising treatment. However, while most recent works have focused on the use of probiotics to modify pre-existing disease, little is known about its role in protecting from the establishment of MS. In this study, we determined whether colonisation with the probiotic bacterium Escherichia coli strain Nissle 1917 (EcN) could be used as a prophylactic strategy to prevent or alter the development of experimental autoimmune encephalomyelitis (EAE), a preclinical model of MS. We found that double gavage (two doses) of EcN before induction of EAE delayed disease onset and decreased disease severity. We also found that EcN-treated mice had decreased amounts of perivascular cuffing, CD4+ T cell infiltration into the CNS, together with significantly decreased absolute numbers of Th1 cells, and reduced activation of microglia. Although further studies are necessary to comprehend the exact protective mechanisms induced, our study supports a promising use of EcN as a probiotic for the prevention of MS.

Scalable high-throughput acoustophoresis in arrayed plastic microchannels.

Microfluidic acoustophoresis is a label-free technique that isolates a purified product from a complex mixture of cells. This technique is well-studied but thus far has lacked the throughput and device manufacturability needed for many medical and industrial uses. Scale-up of acoustofluidic devices can be more challenging than in other microfluidic systems because the channel walls are integral to the resonant behavior and coupling to neighboring channels can inhibit performance. Additionally, the increased device area needed for parallel channels becomes less practical in the silicon or glass materials usually used for acoustofluidic devices. Here, we report an acoustic separator with 12 parallel channels made entirely from polystyrene that achieves blood cell separation at a flow rate greater than 1 ml/min. We discuss the design and optimization of the device and the electrical drive parameters and compare the separation performance using channels of two different designs. To demonstrate the utility of the device, we test its ability to purify lymphocytes from apheresis product, a process that is critical to new immunotherapies used to treat blood cancers. We process a leukapheresis sample with a volume greater than 100 ml in less than 2 h in a single pass without interruption, achieving greater than 90% purity of lymphocytes, without any prepurification steps. These advances suggest that acoustophoresis could in the future aid in cell therapy bioprocessing and that further scale-up is possible.

Internet Use for School-Mandated and Self-Initiated Learning: Good, Bad, or Both?

Because delivery of school assignments and other learning materials has been migrating to online learning environments, use of the Internet for learning has become obligatory for high school students. However, research on the consequences of Internet learning remains equivocal, with some advocating benefits of such learning and others warning about its potential negative effects. In this study, we approach Internet use for learning from a motivational perspective and argue that such learning can be both positive and negative depending on whether it contributes to harmonious or obsessive Internet passion. We test how two types of Internet use for learning, school mandated and self-initiated, may relate to harmonious and obsessive Internet passion among high schoolers in the United States and Russia. The results indicate that Internet use for school-mandated learning is positively related to both harmonious and obsessive Internet passion, and these results hold in both countries. Internet use for self-initiated learning was also positively related to harmonious Internet passion in both Russia and the United States, but was unrelated to obsessive Internet passion in either country. This research not only augments the nomological network of the Internet passion construct but also informs educators on how to incorporate Internet use into the learning environment in ways that are likely to promote harmonious Internet passion and decrease obsessive Internet passion.

A multiplexed microfluidic system for evaluation of dynamics of immune-tumor interactions.

Recapitulation of the tumor microenvironment is critical for probing mechanisms involved in cancer, and for evaluating the tumor-killing potential of chemotherapeutic agents, targeted therapies and immunotherapies. Microfluidic devices have emerged as valuable tools for both mechanistic studies and for preclinical evaluation of therapeutic agents, due to their ability to precisely control drug concentrations and gradients of oxygen and other species in a scalable and potentially high throughput manner. Most existing in vitro microfluidic cancer models are comprised of cultured cancer cells embedded in a physiologically relevant matrix, collocated with vascular-like structures. However, the recent emergence of immune checkpoint inhibitors (ICI) as a powerful therapeutic modality against many cancers has created a need for preclinical in vitro models that accommodate interactions between tumors and immune cells, particularly for assessment of unprocessed tumor fragments harvested directly from patient biopsies. Here we report on a microfluidic model, termed EVIDENT (ex vivo immuno-oncology dynamic environment for tumor biopsies), that accommodates up to 12 separate tumor biopsy fragments interacting with flowing tumor-infiltrating lymphocytes (TILs) in a dynamic microenvironment. Flow control is achieved with a single pump in a simple and scalable configuration, and the entire system is constructed using low-sorption materials, addressing two principal concerns with existing microfluidic cancer models. The system sustains tumor fragments for multiple days, and permits real-time, high-resolution imaging of the interaction between autologous TILs and tumor fragments, enabling mapping of TIL-mediated tumor killing and testing of various ICI treatments versus tumor response. Custom image analytic algorithms based on machine learning reported here provide automated and quantitative assessment of experimental results. Initial studies indicate that the system is capable of quantifying temporal levels of TIL infiltration and tumor death, and that the EVIDENT model mimics the known in vivo tumor response to anti-PD-1 ICI treatment of flowing TILs relative to isotype control treatments for syngeneic mouse MC38 tumors.

Variations in diet cause alterations in microbiota and metabolites that follow changes in disease severity in a multiple sclerosis model.

Multiple sclerosis (MS) is a metabolically demanding disease involving immune-mediated destruction of myelin in the central nervous system. We previously demonstrated a significant alteration in disease course in the experimental autoimmune encephalomyelitis (EAE) preclinical model of MS due to diet. Based on the established crosstalk between metabolism and gut microbiota, we took an unbiased sampling of microbiota, in the stool, and metabolites, in the serum and stool, from mice (Mus musculus) on the two different diets, the Teklad global soy protein-free extruded rodent diet (irradiated diet) and the Teklad sterilisable rodent diet (autoclaved diet). Within the microbiota, the genus Lactobacillus was found to be inversely correlated with EAE severity. Therapeutic treatment with Lactobacillus paracasei resulted in a significant reduction in the incidence of disease, clinical scores and the amount of weight loss in EAE mice. Within the metabolites, we identified shifts in glycolysis and the tricarboxylic acid cycle that may explain the differences in disease severity between the different diets in EAE. This work begins to elucidate the relationship between diet, microbiota and metabolism in the EAE preclinical model of MS and identifies targets for further study with the goal to more specifically probe the complex metabolic interaction at play in EAE that may have translational relevance to MS patients.

Cardiac valve replacement with mitral homograft.

The purpose of this study was to review the results of mitral and tricuspid valve replacement with mitral valve homograft. Twenty-two mitral homografts were used to replace cardiac valves in 20 patients. The mitral valve was replaced in 18 patients, applying the method described by Acar. The tricuspid valve was replaced in 2 patients, attaching one papillary muscle of the graft to the anterior papillary muscle and bringing the other papillary muscle of the graft through a tunnel in the anterior wall of the right ventricle. A concomitant Maze III procedure was performed in 3 patients. Accuracy of the repair was confirmed by intraoperative echocardiography. All patients survived operation and are currently alive. One patient was lost to follow-up. Patients have been followed for up to 3.25 years. All patients have good exercise ability (NYHA class I). Five homografts (25%) have been explanted from the mitral position and one from the tricuspid position. All events occurred during the first year after reoperation. Cardiac valve replacement with mitral valve homograft may be accomplished safely. A technically good operation does not guarantee that the valve will remain competent and an unacceptably high early explant rate may be expected. Use of mitral valve homograft for cardiac valve replacement should be restricted to young patients in whom anticoagulant medication is not indicated or undesirable and for those with resistant infection.

Impact of high transvalvular to subvalvular velocity ratio early after aortic valve replacement with Freestyle stentless aortic bioprosthesis.

Although stentless aortic bioprostheses are associated in general with excellent hemodynamics, a subset of patients exhibit high early postoperative gradients. The present study was performed to evaluate the prevalence and impact of suboptimal hemodynamics early after stentless tissue aortic valve replacement. The early postoperative peak transvalvular to peak left ventricular (LV) outflow tract velocity ratio was > or = 3.0 in 44 (6.7%) of 658 patients in the multicenter, long-term study of the Freestyle stentless aortic valve. Mean gradient, effective orifice area (EOA), and LV mass index were compared between these patients and a control group of 44 patients matched for age, sex, valve size, and implant technique. High velocity ratio was associated with female sex (63.6% v 42.8%, P =.01), smaller valve size (77.3% v 45.3%, < or = 23 mm, P =.0004), and use of the modified subcoronary rather than full root implant technique (90.9% v 70.2% modified subcoronary, P =.01). Mean gradient was significantly higher (P <.05) and EOA lower (P <.05) early postoperative and throughout follow-up among patients with high velocity ratio. LV mass index decreased across time among both groups; patients with high velocity ratio tended to have higher LV mass index with less complete LV mass regression, although the difference did not reach statistical significance. In conclusion, there was a 6.7% incidence of hemodynamics suggestive of significant aortic stenosis early after implantation of a Freestyle stentless aortic valve. Gradients decreased and EOA increased in the first months after surgery, although they remained less favorable. Multiple factors likely play a role in early suboptimal hemodynamics following stentless tissue aortic valve replacement, including factors related to patient population, valve size, implant modality, and implant technique.

Midterm survival of stented versus stentless valves: does concomitant coronary artery bypass grafting impact survival?

The purpose of this study was to examine the impact of concomitant coronary artery bypass grafting (CABG) and valve design on survival following aortic valve replacement (AVR) with stentless and stented bioprostheses. Survival data for 1798 patients undergoing AVR between 1991 and 1997 with either a stentless (Medtronic Freestyle = 700, Toronto SPV = 447; N = 1147) or stented (Hancock II = 224, Carpentier-Edwards SAV = 427; N = 651) valve were analyzed. Bivariable analyses using Kaplan-Meier survival curves and log-rank test were performed to compare survival probabilities by valve type. Multivariable stepwise Cox's proportional hazard models were used to control for potentially confounding variables. Concomitant CABG was performed in 41% of stentless and 46% of stented patients (P =.04). Survival probability at 5 years was 0.84 (95% CI = 0.81, 0.87) for stentless versus 0.79 (95% CI = 0.75, 0.83) for stented patients (P =.004). In the absence of concomitant CABG, survival was superior in stentless (0.84) over stented (0.80) patients, but these differences were not statistically significant (P =.053). In patients that underwent AVR with concomitant CABG, survival was significantly better in stentless patients (0.82) than in stented individuals (0.77, P =.049). The unadjusted hazard ratio for stented versus stentless was 1.44 (95% CI = 1.12, 1.86, P =.005). In the final Cox's proportional hazard model the variables that effected survival were valve type and age in decades. New York Heart Association class at the time of surgery had a marginal effect on survival. The data demonstrate improved midterm survival with stentless versus stented valves. Subgroup analysis suggests survival benefits of stentless valves may be greater in patients who undergo concomitant CABG surgery.

Mitral valve replacement with homograft and Maze III procedure.

BACKGROUND: Mitral valve disease is often accompanied by atrial fibrillation, which may compromise the patient even after the valvular lesion has been repaired. METHODS: Three patients with rheumatic type mitral valve disease and chronic atrial fibrillation were treated by mitral valve replacement with cryopreserved mitral valve homograft and Maze III procedure, as a method to relieve both the valvular pathology and the rhythm disorder. The patients' clinical courses have been followed for up to 1 year after operation. RESULTS: All patients survived operation, and all have normal sinus rhythm. None are taking cardiac medications. CONCLUSIONS: Long-term treatment with warfarin should not be required, and other cardiac medicines may be eliminated following mitral valve replacement with homograft combined with Maze III procedure.

The Maze procedure: the LDS Hospital experience.

At our center we have encouraged consideration of the Maze procedure over noncurative therapies for atrial fibrillation, particularly in patients who have other indications for cardiac surgical intervention. As a result, 78 of the 99 Maze procedures we have performed since 1993 have involved combined procedures. These combined operations included procedures on 1 or more valves in 69 of 78 patients (88%). The unmodified "cut-and-sew" Maze-III technique was used in all patients. There has been no operative mortality, and the median postoperative stay has been 7 days. Cure of atrial fibrillation has been observed in 97% of patients, and pacemaker implantation was required for sick sinus syndrome in 6%. Our results favor broader use of the Maze procedure for symptomatic atrial fibrillation and support use of the original Maze-III technique as the procedure of choice.

Methods for graft size selection in aortic valve-sparing operations.

Simple and reproducible methods for accurate restoration of aortic root dimensions during aortic valve-sparing operations are described. The methods are based on choice of an appropriate size vascular graft based on the measured or desired diameter of the aortic annulus.

Cardiac valve operations using a partial sternotomy (lower half) technique.

BACKGROUND AND AIM: Operations on cardiac valves are being performed more frequently through smaller incisions than traditional midline sternotomy. A variety of alternate incisions have been used, but most of the interest appears to focus on partial sternotomy. The purpose of the study was to review results using a partial lower sternotomy for cardiac valve operations. METHODS: A standard partial lower one-half or two-thirds sternotomy was used for cardiac valve operations in 112 patients. The sternum was divided transversely in the third or second intercostal space and vertically from that point through the xyphoid process. Standard instruments and retraction devices were used. This incision provided adequate exposure for even complex operations to be performed. Small cannulae were placed into the aorta and heart through the primary incision for cardiopulmonary bypass. Vacuum-assisted venous drainage was used. RESULTS: Seventy-four single valve operations were performed. There were 35 double valve and 5 triple valve operations (35.4%) performed. Operative mortality (5.3%) and major complication rates were comparable to full the sternotomy approach. CONCLUSIONS: Partial sternotomy (lower half) provides a smaller incision through which virtually all cardiac valve operations may be performed. Results achieved with this approach are similar to those associated with full sternotomy. The smaller incision is appreciated by patients.

Surgical aspects of endocarditis.

Endocarditis represents a difficult medical problem that must occasionally be treated surgically. Constitutional symptoms of infection are important and are usually the reason that the patient seeks medical attention. Fever is the most common sign of infective endocarditis and a heart murmur, which changes in character or is new, is a significant hallmark. The diagnosis for infective endocarditis is made by high index of suspicion in a patient with valvular heart disease or a prosthetic heart valve and in the presence of fever and a cardiac murmur. A positive blood culture is the hallmark of the diagnosis. The absolute indications for operative intervention are congestive heart failure, unstable prosthetic valve, uncontrolled infection, and relapse after optimal therapy (prosthetic valve). Relative indications for operative intervention are perivalvular extension of the infection, staphylococcal infection of a prosthesis, persistent fever (culture negative), large vegetation, or relapse after optimal therapy (native valve). The principles of surgical management are to remove all infected tissue by thorough debridement back to normal tissue. This is combined with replacement of damaged valves and repair of associated defects. The mortality after operation for infective endocarditis is 15-20%. Late survival after operation for infective endocarditis on a native heart valve is 70-80% at 5 years. Survival falls to 50-80% at 5 years for surgery on an infected prosthetic heart valve.

Superior vena cava obstruction: bypass using spiral vein graft.

BACKGROUND: Previous midterm experience with the composite spiral saphenous vein graft to bypass the obstructed superior vena cava (SVC) has been favorable. This study looks at the long-term results in patients followed for up to 23 years. METHODS: Sixteen patients aged 17 to 68 years had operation for obstruction of the SVC with SVC syndrome caused by benign disease. Eleven patients had fibrosing mediastinitis with or without caseous necrosis, 4 had thrombosis caused by a catheter or a pacemaker electrode, and 1 had spontaneous thrombosis. All operations were performed using a composite spiral vein graft constructed from the patient's own saphenous vein. Graft diameter ranged from 9.5 to 15.0 mm. Ten grafts were from the left innominate vein, and six grafts were from the right or left internal jugular vein. The grafts were placed to the right atrial appendage in all patients except 1. Follow-up extends from 1 month to 23 years 8 months (mean follow-up, 10.9 years). RESULTS: Fourteen of 16 grafts remain patent for up to 23 years, and all patients but 1 are free from SVC syndrome. One patient required revision of the graft for thrombosis 4 days after operation. Two grafts closed during the first year after operation: one because of recurrence of spontaneous venous thrombosis and the other because of aggressive fibrosing mediastinitis requiring operation for graft revision three times over a 12-year period prior to death. CONCLUSIONS: These data demonstrate that a spiral vein bypass graft for treatment of the obstructed SVC relieves SVC syndrome and has excellent long-term patency.

The effect of prosthetic valve type on survival after aortic valve surgery.

A number of recent reports have suggested that valve design has an influence on long-term survival after aortic valve replacement (AVR). The present study examines the clinical results of two large multicenter trials of the Hancock II stented and Medtronic Freestyle stentless bioprosthetic valves. In all cases a subcoronary implant technique was used. All patients were operated on between 1991 and 1994, and all patients were monitored for 5 years. The 5-year actuarial survival rate was 86% for Freestyle and 77% for Hancock patients (P<.05). Late mortality occurred in 40 Freestyle patients (8.8%) compared with 36 Hancock II patients (16.1%, P = .0074). Cox's proportional hazard models were used to identify independent predictors of 5-year survival for the two groups. Hazard ratio (HR) and P value are presented in parentheses. The final analysis included the interactive variable valve*age. The resultant model indicates that the interaction of age and valve type has a significant effect on outcome. In patients < or =60 years of age at the time of operation, AVR with a Hancock II valves was associated with nearly a fivefold risk of death compared with patients of the same age who received a Freestyle valve (HR = 4.97, P = .0004). However, this survival advantage decreased by 50% with each decade thereafter (valve*age interaction HR = 0.50, P = .0027). Our data indicate that AVR with a stentless valve confers a survival advantage to the patient. The probability of dying within 5 years of surgery is 50% greater in patients who received a Hancock II versus a Freestyle valve (HR = 1.50, P = .0442). However, this survival advantage is most prominent in younger patients (<60 years of age) where the probability of death is fivefold greater with Hancock than Freestyle valves. With advancing age the benefits of stentless valves are diminished.

Aortic valve replacement with Medtronic Freestyle bioprosthesis: 5-year results.

The Medtronic Freestyle aortic root bioprosthesis has been implanted in patients since August 1992. This study reviews clinical and echocardiographic results at midterm (5 years) after implantation. The Freestyle bioprosthesis was implanted in 1,100 patients in a 21-center Food and Drug Administration clinical trial from August 1992 to October 1998. The device was implanted (1) as a subcoronary valve replacement, (2) as a complete aortic root replacement (full-root), or (3) as a root inclusion. Patients were followed annually by clinical examination and echocardiography. There were 47 deaths early after operation (7.1%). There were 2,478 patient-years of follow-up during which there were 99 deaths or 4.0/pt.-yr. Before implantation, 73% of patients were in New York Heart Association functional class III or IV. After operation, 95% were in class I or II. Transvalvular gradient 4 years after operation was low (7.5+/-5.3 mm Hg) for all valve sizes (subcoronary implant). Small valves (19 and 21 mm) had mean gradients (10.2+/-3.0, 9.1+/-4.4 mm Hg). There was no or mild valve insufficiency in 98% of patients. Actuarial analysis at 5 years showed the rate for freedom from thromboembolism of 86% in subcoronary implant and 93% in full root replacement. Freedom from endocarditis was 98%. Freedom from reoperation for explant of the valve highest in patients having full root replacement (98%) and lower with root inclusion (94%). There were 20 bioprostheses explanted; 10 for endocarditis, 8 for technical reasons, and 2 for structural deterioration. The Medtronic Freestyle bioprosthesis (1) has excellent hemodynamic performance, (2) techniques for insertion that result in a competent valve, (3) low rates of thromboembolism and endocarditis, and (4) a rare rate of structural deterioration at 5 years.