Robotic excision of atrial myxoma

BACKGROUND

Advances in optics and instrumentation with the da Vinci S Surgical System have facilitated minimally invasive and robotic cardiac procedures including mitral valve repair and atrial myxoma excision. We report our retrospective data comparing robotically assisted myxoma excision with standard median sternotomy excision.

METHODS

Data were collected for cardiac myxoma resection performed between January 2000 and December 2009. The resulting cohort included a total of 57 patients. These patients were grouped into two categories: robotic-assisted (n = 17) surgical procedures and traditional (nonrobotic; n = 40) surgical procedures. Presurgical and surgical risk factors were examined.

RESULTS

Univariate analysis comparing the surgical procedure groups and surgical risk factors found a significant difference in 3 of the 14 variables. Cannulation in all patients undergoing robotic-assisted cardiac myxoma excision was performed through cannulating the common femoral artery and vein while cannulation for the traditional procedures was performed using the aorta and atrium except for two patients. For aortic occlusion, 14 of the robotic-assisted cardiac myxoma patients had balloon occlusion and 34 of the traditional cardiac myxoma patients had aortic cross-clamp occlusion. Operating time was significantly shorter for robotic cases (2.7 hours) compared with traditional cases (3.5 hours).

CONCLUSION

Robotic excision of atrial myxomas is safe and may be an alternative to traditional open surgery in selected patients.

Improving satisfaction ratings of surgical patients from referral to follow-up in the faculty medical center clinic

OBJECTIVE

The objective of this study was to evaluate patient satisfaction in an outpatient community-based surgical clinic to seek opportunities for improvement.

METHODS

A paper survey was distributed to patients at the Faculty Medical Center Clinic over a 12-week period. The survey allowed patients to rate their experience on a 5-point scale from "very dissatisfied" to "very satisfied." The survey addressed referral to the clinic, appointment scheduling, visit experience, wait times, laboratory testing, and satisfaction with surgery. Separate from the surveys, data were collected regarding wait time in clinic prior to being placed in an examining room, time spent waiting for the physician, time spent with the physician, overall time spent in clinic, and appointment time to surgery.

RESULTS

During the 12-week time period, 87 surveys were returned from patients in the surgery clinic for a 69% response rate. Most patients were referred to the surgery clinic from the emergency department or their primary care physicians at 44% and 43%, respectively. Just over half of the patients responded that they were "very satisfied" with their overall experience. Of those surveyed, 40% of patients were "very satisfied" with their wait time for the first visit to the clinic, 52% with time in waiting room, 43% with time in examining room, and 47% with time spent with physician. Only 16.4% of patients were "very dissatisfied" or "mostly dissatisfied" with time waiting for appointment, 17.9% with time available for appointment, 14.3% with time in waiting room, 18.2% in time waiting in examination room for the physician, and 20.9% of time wait to schedule surgery. Data were also collected on 203 surgical clinic patients during this time. Of the 203 patients, 55% were new patients, 31% were postoperative patients, and 14% were in the clinic for another type of visit.

CONCLUSIONS

Overall patient satisfaction was good for the clinic, yet there were areas to improve. Efficiency of scheduling patients, improving wait time for waiting room, examining room, and time prior to scheduling surgery are areas that need improvement. Modification of the current practice at the surgery clinic could result in improvement of patient satisfaction in future evaluation.

Predictors and outcomes of prolonged ventilation after coronary artery bypass graft surgery

This study investigated and compared the risk factors and outcomes of patients undergoing coronary artery bypass graft surgery with and without the occurrence of prolonged mechanical ventilation. Data in a cardiac surgery database were examined retrospectively. Data selected included any isolated coronary artery bypass graft surgery performed by the surgical group from August 2005 to June 2009. The resulting cohort included a total of 2933 patients which was comprised of 116 patients with a ventilation time of greater than 72 hours (prolonged ventilation) and 2817 patients with a ventilation time of 72 hours or less (no prolonged ventilation). Patients with a prolonged ventilation time were matched (1:3 ratio) to patients not requiring a prolonged ventilation time by year of surgery resulting in our study cohort of 464 patients. To generate the unadjusted risks of each factor, χ(2) and t test analysis were performed. Logistic regression analysis was then used to investigate the adjusted risk between cases and controls and each of the significant variables. χ(2) and t tests were conducted comparing cases and controls with the outcome variables. Patients undergoing coronary artery bypass graft that experienced a prolonged ventilation time (cases) were more likely female, had a New York Hospital Association functional class of III or IV, and had a longer perfusion time. There was no significant difference between cases and controls with diabetes, chronic obstructive pulmonary disease, left ventricular ejection fraction, or body mass index while controlling for all significant risk factors. Careful patient selection and preparation during preoperative evaluation may help identify patients at risk for prolonged mechanical ventilation and thus help prevent the added morbidity and mortality associated with it.

Predictors and Outcomes of Prolonged Ventilation after Coronary Artery Bypass Graft Surgery

This study investigated and compared the risk factors and outcomes of patients undergoing coronary artery bypass graft surgery with and without the occurrence of prolonged mechanical ventilation. Data in a cardiac surgery database were examined retrospectively. Data selected included any isolated coronary artery bypass graft surgery performed by the surgical group from August 2005 to June 2009. The resulting cohort included a total of 2933 patients which was comprised of 116 patients with a ventilation time of greater than 72 hours (prolonged ventilation) and 2817 patients with a ventilation time of 72 hours or less (no prolonged ventilation). Patients with a prolonged ventilation time were matched (1:3 ratio) to patients not requiring a prolonged ventilation time by year of surgery resulting in our study cohort of 464 patients. To generate the unadjusted risks of each factor, χ2 and t test analysis were performed. Logistic regression analysis was then used to investigate the adjusted risk between cases and controls and each of the significant variables. χ2 and t tests were conducted comparing cases and controls with the outcome variables. Patients undergoing coronary artery bypass graft that experienced a prolonged ventilation time (cases) were more likely female, had a New York Hospital Association functional class of III or IV, and had a longer perfusion time. There was no significant difference between cases and controls with diabetes, chronic obstructive pulmonary disease, left ventricular ejection fraction, or body mass index while controlling for all significant risk factors. Careful patient selection and preparation during preoperative evaluation may help identify patients at risk for prolonged mechanical ventilation and thus help prevent the added morbidity and mortality associated with it.

Differences in public belief and reality in the care of operative patients in a teaching hospital

OBJECTIVE

The accreditation Council for Graduate Medical Education (ACGME) restricts residents from working more than 80 hours per week averaged over a 4-week period. No such restriction exists, however, for attending surgeons. Little exploration has been done of the public's perception of the number of hours that surgeons work and how residents work with the staff surgeons at a teaching institution.

METHODS

A survey was designed to study the public's belief on surgeon work hours and habits. The survey also asked their opinion on resident involvement. All patients and accompanying persons arriving through the Surgicare Center for elective procedures older than age 18 were surveyed. The overall survey responses were calculated, and the results then were stratified by sex, age, race, and education.

RESULTS

Of the 1516 surveys distributed, 370 were completed and returned (24.4%). Of those responding, 91% believed that a work hour limit should be in place for surgeons, and 77% believed the limit should be 12 consecutive hours or less. Eighty-four percent of the population believed that limit should be in place on the hours/week that a surgeon works, and 68% believe that it should be 60 hours or less. Although 82% would reschedule if they knew their surgeon had less than 4 hours of sleep the night before their procedure, 79% trust their surgeon's judgment to cancel if he/she were too tired. Only 28% of those surveyed were aware whether a resident was involved in their care, and 14% were against resident involvement. Respondents also were asked if the attending surgeon deemed a resident capable, then what percent of the procedure should the resident be able to perform? Ninety-one percent of those surveyed believed that the attending should be present for the entire case, and 78% believed that they should not be able to schedule more than 1 procedure at any given time.

CONCLUSIONS

These findings illustrate a difference between the public's beliefs in regard to the hours a surgeon should be permitted to work and the reality of a surgeon's work life. Although the public may not be aware of the surgeon's schedule at a given time, they do trust the surgeon would cancel if too fatigued. The majority surveyed were not aware of resident involvement, but they trusted the attending surgeon's judgment with deciding how much of the actual procedure he/she could perform. With work-hour restrictions and resident involvement continuing to evolve, keeping the public informed should be a priority.

Does participation in graduate medical education contribute to improved patient outcomes as outlined by Surgical Care Improvement Project guidelines?

BACKGROUND

Patient quality outcomes are a major focus of the health care industry. It is unknown what effect involvement in graduate medical education (GME) has on patient outcomes. The purpose of this study is to begin to examine whether GME involvement in postoperative care impacts patient quality outcomes.

METHODS

The retrospective cohort included all patients who underwent a nonemergent colectomy from January 1, 2007 to January 1, 2008 at a 2-hospital system. Data collected included patient demographics, patient quality outcomes, complications, and GME involvement. Patient quality outcomes were based on compliance with the Surgical Care Improvement Project (SCIP) guidelines.

RESULTS

A total of 159 nonemergent colectomies were analyzed. The GME group accounted for 116 (73%) patients. A significant difference was found in several SCIP process-based measures of quality when comparing the GME group with the non-GME group. Postoperative antibiotics were more likely to be stopped within 24 hours (p = 0.010), and preoperative heparin and postoperative deep vein thrombosis (DVT) prophylaxis were more likely to be administered (p < 0.001). Additionally, patients in the GME group showed improved quality outcomes as there were significantly fewer postoperative complications (p < 0.001) and a shorter duration of stay (p = 0.008). The use of gastrointestinal prophylaxis was more common in the non-GME group (p = 0.002). No significant differences were observed between the 2 groups in respect to age, sex, diabetes, preoperative antibiotics, antibiotics, 1 hour before surgery, postoperative antibiotics, and continuation of home beta blockade.

CONCLUSIONS

GME at teaching institutions has a positive impact on patient quality outcomes. At our institution, many of the SCIP measurable outcomes had improved compliance if an attending physician participated in the GME program.

Gender differences in outcomes following aortic valve replacement surgery

OBJECTIVE

The objective of this study was to assess outcome differences in aortic valve replacement based on gender.

METHODS

A study from a ten-year hospitalization cohort with prospective data collection was conducted. Included in the study were patients undergoing aortic valve replacement surgery between March 1997 and July 2003 (N=406). There were 223 males and 183 females included in the study. The study examined 41 potential confounding risk factors and 16 outcome variables.

RESULTS

Univariate analysis on potential confounding risk factors revealed a significant difference between males and females on 12 factors. Co-morbid disease, hypertension, current vascular disease, aortic insufficiency, body surface area, blood added on pump, and annulus size significantly correlated with age. The correlation resulted in five confounding risk factors: age, tobacco history, obesity, left ventricular hypertrophy, and creatinine level. Logistic regression analysis found that after controlling for age, tobacco history, obesity, left ventricular hypertrophy, and creatinine level, there is no difference between males and females on outcomes following aortic valve replacement. Additionally, choice of vascular prosthesis had no impact on post-operative outcomes.

CONCLUSION

After controlling for confounding variables, similar outcomes were observed for males and females undergoing aortic valve replacement.

Predictors of type II neurologic complications after coronary artery bypass graft surgery

The study objective was to determine predictors, and adverse outcomes of postoperative type II neurologic complications. An 11-year cohort (N=12,706) study with 595 coronary artery bypass graft (CABG) patients with a neurologic complication, and 7793 patients without any neurologic complications was conducted. This study examined 26 potential risk factors and 13 outcome variables. Logistic regression analysis found that patients were more likely to experience a neurologic complication after CABG if they were older than 70 years of age [odds ratio (OR), 3.8; 95% confidence interval (CI), 3.1-4.5; P < 0.001], had a previous intervention within 10 days before surgery (OR, 3.4; 95% CI, 1.4-8.3; P = 0.008), or had a higher creatinine level (OR, 0.9; 95% CI, 0.95-0.99; P = 0.013). Additionally, there was a significant difference between CABG patients with and without neurologic complications on 12 outcome variables. Type II neurologic complications after CABG are common and associated with an increased risk of postoperative morbidity and mortality.

Computerized rounding in a community hospital surgery residency program

BACKGROUND

With the institution of the 80-hour work week, residency programs have worked to institute programs that decrease the time that residents spend in the hospital while maintaining patient safety. This study was intended to assess the amount of time saved using computerized patient information in the form of a personal data assistant (PDA).

METHODS

A community hospital surgical residency program with 22 residents initially collected data daily for 4 weeks without PDA use. Data included preround time, check-out time, total number of patients, number of medical/surgical patients, and number of intensive care unit patients. The definition of prerounding time was started when residents first began collecting information on their patients in the morning until 6:00 am. Check-out time started at 5:00 pm and lasted until the discussion of patient care with the night team had finished. Residents were then given PDAs allowing immediate up-to-date access to patient information, which most importantly included current vital signs, laboratory data, radiological dictations, medication lists, and fluid intake and output. After a 4-week acquaintance period with the PDA had passed, data were again collected from the residents daily for 4 weeks. Daily averages for each week and an overall total average were calculated. Daily averages were also calculated for each PGY level. Paired t-tests compared the pre-PDA and post-PDA total averages.

RESULTS

No significant difference was found between the total number of patients pre-PDA and post-PDA (7.6 and 7.6, respectively, p = 0.98), the average number of medical/surgical patients (4.7 and 7.1, respectively, p = 0.16), or the average number of intensive care unit patients (2.6 and 0.4, respectively, p = 0.06). Also, no significant difference was found between pre-PDA and post-PDA with average check-out time (24.5 minutes and 21.9 minutes, respectively, p = 0.06). However, a significant decrease in rounding time occurred with pre-PDA round time at 50.5 minutes and post-PDA round time at 40.7 minutes (p = 0.02).

CONCLUSION

Results of this study support the hypothesis that the prerounding time dramatically decreases with the PDA compared to without. Not only does this decrease in time help to keep residents under the 80-hour work week rule, but also it helps to eliminate much of the confusion that can cause patient safety issues.

Gender Differences in Diabetic Patients Following Coronary Artery Bypass Graft Surgery

OBJECTIVE

The objective was to examine the influence of gender in diabetic patients following coronary artery bypass graft (CABG) surgery.

METHODS

A study from an 11-year hospitalization cohort with prospective data collection was conducted. Included in the study were diabetic patients undergoing CABG surgery between October 1993 and May 2004 (n = 2781). Patients who underwent any surgery other than CABG or had a previous cardiac surgery were excluded. The study examined 25 risk factors and 14 outcome variables.

RESULTS

Twelve risk factors were found to be significantly different between male and female diabetic patients undergoing CABG. Correlation coefficients were computed among the 12 significant risk factors. Three main risk factors emerged: age 70 years or greater, abnormal LVH, and number of grafts. For outcome variables, females experienced more renal complications, intraoperative complications, longer hospital stay, and mortality. Logistic regression analysis showed that after controlling for age, LVH, and number of grafts, female diabetic patients undergoing CABG were more likely to experience intraoperative complications (OR 1.8, 95% CI 1.1-3.0, p = 0.025) and longer hospital stay (OR 0.99, 95% CI 0.97-0.99, p = 0.039). However, there was no significant difference between male and female diabetic patients after CABG surgery with renal complications (OR 1.39, 95% CI 0.95-2.1, p = 0.132) or mortality (OR 1.6, 95% CI 0.85-2.8, p = 0.153).

CONCLUSION

Female diabetic patients, when compared to male diabetic patients undergoing CABG, have significantly more intraoperative complications and longer hospital stays following surgery.

Totally endoscopic mitral valve repair using a robotic-controlled atrial retractor

PURPOSE

Our aim was to assess the feasibility of totally endoscopic robotic mitral valve surgery using a novel atrial retractor manipulated by a fourth arm da Vinci surgical system (Intuitive Surgical Inc, Sunnyvale, CA).

DESCRIPTION

Eighteen patients with mitral valve disease underwent totally endoscopic mitral valve surgery using the retractor. It was inserted in the second or third intercostal space just lateral to the sternum, and it was manipulated at the robotic console for dynamic exposure of the valve structures.

EVALUATION

Mitral valve repair procedures were feasible in all patients with the robotic-controlled atrial retractor providing superior exposure of the mitral valve anatomy. The time until satisfactory exposure of the mitral valve was noticeably decreased with the robotic retractor. All patients were discharged home in sinus rhythm and transesophageal echocardiography revealed competent mitral valves.

CONCLUSIONS

The EndoWrist atrial retractor (Intuitive Surgical Inc) facilitated complex totally endoscopic mitral valve surgery, including concomitant procedures, regardless of pathology with excellent clinical outcomes.

Peripheral vascular disease and outcomes following coronary artery bypass graft surgery

HYPOTHESIS

There is an increased operative risk in patients with a history of peripheral vascular disease (PVD) who undergo coronary artery bypass grafting (CABG). There are also outcome differences associated with these patients.

DESIGN

A study from a 10-year hospitalization cohort with prospective data collection.

SETTING

Multiple hospitals in the Greater Cincinnati area with 1 surgical group of cardiac surgeons.

PARTICIPANTS

Cases were CABG patients with PVD, which was defined as having a history of type 1 neurologic injury, prior vascular surgery, or current vascular disease (n = 1561). Controls were CABG patients without PVD (n = 6328).

INTERVENTIONS

The study examined 42 potential confounding risk factors and 16 outcome variables.

RESULTS

Twenty-nine potential risk factors were found to be significantly different between CABG patients with and without PVD. Twenty-six confounding risk factors were correlated with 3 factors. Logistic regression analysis showed that even after controlling for sex, significant associative disorders, and other procedures, CABG patients with PVD still experienced more arrhythmias requiring treatment (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.03-1.33; P = .01), neurological complications (OR, 1.7; 95% CI, 1.43-2.07; P<.001), pulmonary complications (OR, 1.4; 95% CI, 1.23-1.62; P<.001), low output (OR, 1.3; 95% CI, 1.09-1.45; P = .001), and intraoperative complications (OR, 1.39; 95% CI, 1.06-1.83; P = .02).

CONCLUSIONS

Patients with a PVD history undergoing CABG had more coexistent risk factors. These patients also exhibited higher rates of cardiac, systemic, renal, neurologic, and pulmonary complications.

Clinical predictors of mortality from infective endocarditis

A cohort study with prospective data collection was conducted to determine which risk factors and outcome variables are statistically significant clinical predictors of mortality from infective endocarditis. A study was performed from an eleven-year, hospitalization cohort (N=11,230) in which the data were collected prospectively. The study examined 21 potential risk factors and 14 outcome variables. The risk factors were categorized into these various groups: patient factors, cardiac factors, co-morbidities, operative factors, infectious factors, and complications. The outcome variables were categorized into operative factors, infectious factors, and complications. Inclusion criteria included patients with endocarditis (N=87). Longer operative time, operative complications, and postoperative complications. Overall mortality was 11.5 percent (N=10). Endocarditis patients who died were significantly older (p=0.023) and had a longer pump time (p=0.017) than those who survived. Endocarditis patients who died were more likely to experience an unstable hemodynamic status (p=0.012). There was a significant difference between survival and non-survival of patients with endocarditis on nine outcome variables. They were more likely to require a re-operation for bleeding (p=0.034). Renal complications (p=0.016), neurological complications (p=0.004), pulmonary complications (p=0.001), intra-operative complications (p=0.035), and IAPB (p<0.001) were all more likely to occur in endocarditis patients who died. There are risk factors that serve as predictors of mortality from infectious endocarditis. These include age greater than 65 years, longer pump time, and unstable hemodynamic status. Outcome variables that reflected significant mortality included operative complications and post-operative complications. These factors may identify those patients with infective endocarditis eligible for more aggressive treatment.

Predictors and outcomes of extended intensive care unit length of stay in patients undergoing coronary artery bypass graft surgery

OBJECTIVE

To assess risk predictors of increased intensive care unit (ICU) length of stay in patients undergoing isolated coronary artery bypass surgery (CABG) and assess outcomes associated with increased ICU length of stay.

METHODS

We conducted a nested case-control study from a 9-year hospitalization cohort with prospective data collection (N = 9869). Cases were CABG patients with ICU greater than or equal to 168 hours (N = 236) and controls were CABG patients with an ICU stay of less than 168 hours (N = 708). We examined 15 risk factors and 11 outcomes.

RESULTS

Nine risk factors proved significant in predicting an increased ICU length of stay. Cases were more likely to be older, with an increased pump time, and a lower body surface area. Cases tended to be female, with COPD, hypertension, and undergoing an urgent surgical procedure. Controls tended to have hypercholesterolemia and abnormal left ventricular hypertrophy. There was no significant difference between the cases and controls for the remaining six risk factors. Five of the nine significant predictors correlated with four predictors: age, urgent surgical procedure, pump time, and chronic obstructive pulmonary disorder (COPD). Using logistic regression analysis, we found that patients undergoing CABG had an increased ICU length of stay if they were older than 70 years (OR 2.59, 95% CI 1.86 to 3.62), with longer pump time (OR 2.45, 95% CI 1.75 to 3.44), had COPD (OR 2.04, 95% CI 1.36 to 3.05), and had an urgent surgical procedure (OR 1.59, 95% CI 1.12 to 2.26). Patients with an extended ICU length of stay were also found to experience 11 additional negative outcomes.

CONCLUSION

In patients undergoing CABG surgery an increased age, increased pump time, COPD, and urgent surgical procedure significantly increased the risk of an increased ICU length of stay. Patients with an increased ICU length of stay also experienced more negative outcomes.

Attracting medical students to surgical residency programs

With the goals of creating a better match between medical students and general surgery programs and providing a program that is desirable to medical students who are interested in pursuing careers in surgery, a survey was designed to categorize student interests and to determine what factors are used in choosing a general surgery program. The survey focused on the reasons that surgical resident candidates select a program. Each statement was rated for importance on a 5-point scale, and then the top 10 statements were ranked in order of importance. The survey was distributed to 19 community hospitals, 23 university programs, and medical students interviewing for surgical residency. A total of 286 surveys were returned from 18 programs and medical students. The statements with the three highest ratings were "amount of operative exposure," "diversity of operative cases," and "perceived relationships among faculty and residents." "Amount of operative exposure," "diversity of operative cases," and "ability to pursue fellowship training after residency" received the top rankings. There was a significant difference between men and women in the ratings of three statements. However, there was no difference with the ranking of the statements. There was also a significant difference between residents early and late in their training on ratings of five statements and on the ranking of two statements. The ratings of six statements were significantly different between community and university programs. A significant difference between types of program was also found with the rankings of four statements. There was a difference between small and large programs on two ratings of statements and one ranking. This data provides a useful resource for programs and candidates in preparing for candidate/residency selection.

Attracting Medical Students to Surgical Residency Programs

With the goals of creating a better match between medical students and general surgery programs and providing a program that is desirable to medical students who are interested in pursuing careers in surgery, a survey was designed to categorize student interests and to determine what factors are used in choosing a general surgery program. The survey focused on the reasons that surgical resident candidates select a program. Each statement was rated for importance on a 5-point scale, and then the top 10 statements were ranked in order of importance. The survey was distributed to 19 community hospitals, 23 university programs, and medical students interviewing for surgical residency. A total of 286 surveys were returned from 18 programs and medical students. The statements with the three highest ratings were “amount of operative exposure,” “diversity of operative cases,” and “perceived relationships among faculty and residents.” “Amount of operative exposure,” “diversity of operative cases,” and “ability to pursue fellowship training after residency” received the top rankings. There was a significant difference between men and women in the ratings of three statements. However, there was no difference with the ranking of the statements. There was also a significant difference between residents early and late in their training on ratings of five statements and on the ranking of two statements. The ratings of six statements were significantly different between community and university programs. A significant difference between types of program was also found with the rankings of four statements. There was a difference between small and large programs on two ratings of statements and one ranking. This data provides a useful resource for programs and candidates in preparing for candidate/residency selection.

Predictors and outcomes of sternal wound complications in patients after coronary artery bypass graft surgery

We sought to assess predictors and outcomes of sternal wound complications in patients after coronary artery bypass grafting (CABG). A nested, case-control study from a 10-year hospitalization cohort with prospective data collection was conducted. Included in the cohort were patients age 18 and above undergoing CABG surgery between March 1997 and July 2003 (n = 7889). Patients who underwent any surgery other CABG were excluded. Cases were matched to controls 1:3 on year of surgery. Cases were CABG patients with sternal wound complications, which was defined as requiring antibiotics and/or topical treatment, requiring extra nursing care, dehiscence, or requiring surgical intervention (n = 89). Controls were CABG patients without sternal wound complications (n = 267). The study examined 29 risk factors and 10 outcome variables. Univariate analysis on the risk factors revealed 10 significant risk factors. Logistic regression analysis was conducted and the risk factors that significantly predicted sternal wound complications after CABG surgery included older age (odds ratio [OR] = 0.85, 95% confidence interval [CI] 0.808-0.892), previous CABG surgery (OR = 3.9, 95% CI 1.03-15.37), and in class three or four of the New York Heart Association functional class (OR = 2.8, 95% CI 1.27-6.12). There was a significant difference between CABG patients with and without sternal wound complications on nine outcome variables. Of the 29 predictors of post-CABG sternal wound infections being examined, 10 proved to be significant. Further analysis demonstrated only three variables that significantly predicted sternal wound complications. Older age, previous CABG surgery, and class three or four of the New York Heart Association functional class predispose CABG patients to sternal wound infections.

Predictors and Outcomes of Sternal Wound Complications in Patients after Coronary Artery Bypass Graft Surgery

We sought to assess predictors and outcomes of sternal wound complications in patients after coronary artery bypass grafting (CABG). A nested, case-control study from a 10-year hospitalization cohort with prospective data collection was conducted. Included in the cohort were patients age 18 and above undergoing CABG surgery between March 1997 and July 2003 (n = 7889). Patients who underwent any surgery other CABG were excluded. Cases were matched to controls 1:3 on year of surgery. Cases were CABG patients with sternal wound complications, which was defined as requiring antibiotics and/or topical treatment, requiring extra nursing care, dehiscence, or requiring surgical intervention (n = 89). Controls were CABG patients without sternal wound complications (n = 267). The study examined 29 risk factors and 10 outcome variables. Univariate analysis on the risk factors revealed 10 significant risk factors. Logistic regression analysis was conducted and the risk factors that significantly predicted sternal wound complications after CABG surgery included older age (odds ratio [OR] = 0.85, 95% confidence interval [CI] 0.808–0.892), previous CABG surgery (OR = 3.9, 95% CI 1.03–15.37), and in class three or four of the New York Heart Association functional class (OR = 2.8, 95% CI 1.27–6.12). There was a significant difference between CABG patients with and without sternal wound complications on nine outcome variables. Of the 29 predictors of post-CABG sternal wound infections being examined, 10 proved to be significant. Further analysis demonstrated only three variables that significantly predicted sternal wound complications. Older age, previous CABG surgery, and class three or four of the New York Heart Association functional class predispose CABG patients to sternal wound infections.

Autologous blood transfusion in elective cardiac valve operations

BACKGROUND AND AIM OF STUDY

The aim of this study was to detect any outcome differences between patients who donated autologous blood versus nondonors undergoing nonemergent cardiac valve surgery. Of further interest was whether autologous donors required less allogeneic blood products overall than patients who did not donate.

METHODS

We conducted a nested case-control study in which data were collected prospectively on 225 variables. Cases underwent nonemergent, cardiac valve surgery and donated autologous blood products (n = 40). Controls also had nonemergent, cardiac valve surgery but did not donate autologous blood products (n = 120). Cases were matched to controls 1:3 on age (+/-3 years), gender, and New York Heart Association Functional Classification. We controlled for 12 potential confounding variables and examined 17 outcomes of interest. To generate the unadjusted risks of each outcome, chi-square and t-tests were performed comparing cases and controls to each outcome of interest. Then logistic regression analysis investigated the adjusted risk between cases and controls and for the outcomes of interest, each controlling for the potential confounding variables.

RESULTS

There were no significant differences between the cases and controls for 11 of the 12 possible confounding variables. Controls had significantly more chronic obstructive pulmonary disorder. There were no significant differences between cases and controls for 13 of the 17 outcomes of interest. Autologous blood donors received more total packed red blood cells (PRBCs) (p = 0.0373) and more total fresh frozen plasma than controls (p = 0.0002). Fewer autologous blood donors required allogeneic packed red blood cell transfusion (p = 0.0134), and the total length of stay was shorter for autologous donors (p = 0.0782).

CONCLUSION

Four of the 17 outcomes of interest were different for patients who donated autologous blood versus those who did not. Our experience demonstrated that elective cardiac valve surgery can safely reduce (by 18.3%) the need for allogeneic PRBCs by utilizing preoperative autologous blood donation.

Gender Differences in Outcomes after off-Pump Coronary Artery Bypass Graft Surgery

Our objective was to assess surgical outcomes between male and female patients undergoing off-pump coronary artery bypass grafting (CABG). The study was conducted from a 10-year hospitalization cohort (n = 11,230) in which the data were collected prospectively. Inclusion criteria included an off-pump CABG-only procedure. There were 526 men and 250 women included in the study. Fourteen potential confounding risk factors and 14 outcome variables were examined. Six potential risk factors were found to be significantly different between men and women. Men were younger (P = 0.014), had a larger body surface area (P < 0.001), a higher creatinine level (P < 0.001), required more grafts (P < 0.001), and were more likely to have a cerebrovascular history (P = 0.020) and a history of tobacco use (P ≤ 0.001). Logistic regression analysis showed that even after controlling for age, body surface area, creatinine level, number of grafts, and tobacco history, women had longer length of hospitalization (odds ratio, 1.97; 95% confidence interval, 1.28–3.04, P = 0.002) and more sternal wound complications than men (odds ratio, 1.07; 95% confidence interval, 1.01–2.11, P = 0.028) after off-pump CABG. Although not statistically different, women had lower operative mortality than men after off-pump CABG (0.8% [2 of 10] compared with 1.5% [8 of 10], respectively). Despite women requiring a longer hospitalization and having a greater incidence of sternal wound infections than men, there was no significant difference in mortality.

Gender differences in outcomes after off-pump coronary artery bypass graft surgery

Our objective was to assess surgical outcomes between male and female patients undergoing off-pump coronary artery bypass grafting (CABG). The study was conducted from a 10-year hospitalization cohort (n = 11,230) in which the data were collected prospectively. Inclusion criteria included an off-pump CABG-only procedure. There were 526 men and 250 women included in the study. Fourteen potential confounding risk factors and 14 outcome variables were examined. Six potential risk factors were found to be significantly different between men and women. Men were younger (P = 0.014), had a larger body surface area (P < 0.001), a higher creatinine level (P < 0.001), required more grafts (P < 0.001), and were more likely to have a cerebrovascular history (P = 0.020) and a history of tobacco use (P < or = 0.001). Logistic regression analysis showed that even after controlling for age, body surface area, creatinine level, number of grafts, and tobacco history, women had longer length of hospitalization (odds ratio, 1.97; 95% confidence interval, 1.28-3.04, P = 0.002) and more sternal wound complications than men (odds ratio, 1.07; 95% confidence interval, 1.01-2.11, P = 0.028) after off-pump CABG. Although not statistically different, women had lower operative mortality than men after off-pump CABG (0.8% [2 of 10] compared with 1.5% [8 of 10], respectively). Despite women requiring a longer hospitalization and having a greater incidence of sternal wound infections than men, there was no significant difference in mortality.

Deciphering mesenteric venous thrombosis: imaging and treatment

The principal cause of a high mortality rate in mesenteric vein thrombosis (MVT) is a delay in diagnosis. Recent data indicate that the mortality rate is decreasing owing to earlier diagnosis and anticoagulation. The authors examined the treatment profile of MVT to see how the increased use of imaging and early anticoagulation has impacted this process. They retrospectively analyzed the treatment paradigm with acute MVT at one institution over a 10-year period. Twenty-three patients were identified. Data were analyzed using chi-squares and Student's t tests. Twenty-three patients (11 men and 12 women with an average age of 51.74 +/-14.8 years) were identified with acute MVT between the years of 1993 and 2003. Five patients had splenic vein thrombosis, 17 had superior mesenteric vein thrombosis, 1 had inferior mesenteric vein thrombosis, and 12 had portal vein thrombosis. Nine patients had combination mesenteric vein segment thrombosis. Thrombolytics were utilized in a total of 6 patients. Four of the 6 patients in whom lytics were utilized had combined mesenteric vein thrombosis; however, these 4 patients did not require surgical intervention. There was no significant difference in length of hospital stay between patients taking lytics versus patients treated with traditional anticoagulation with heparin (p = 0.291). A hypercoagulable state was identified in 66.7% of the patients. Four patients required surgical intervention. The overall mortality rate was 8.7% (2 of 23). The use of thrombolytics was associated with a significant mortality (p = 0.04). The use of antibiotics made no difference in mortality (p = 0.235), nor did antibiotic use influence length of hospitalization (p = 0.192). MVT is relatively rare, and often the delay in diagnosis increases the mortality rate. In the majority of cases prompt anticoagulation will preserve bowel viability and decrease mortality and morbidity rates. The majority of patients do not need surgery. There is a marked increase in mortality rate when these patients progress to surgical intervention. An increased awareness and early diagnosis has led to decreased morbidity and mortality rates.

Influence of sex on lung cancer histology, stage, and survival in a midwestern United States tumor registry

BACKGROUND

A study was performed to identify differences between men and women with regard to lung cancer type, stage at diagnosis, and survival in a single hospital system cancer registry.

PATIENTS AND METHODS

A retrospective cohort study was designed based on a study population drawn from the lung cancer tumor registry at a single hospital system composed of 2 independent hospitals in the Midwestern United States. This database included all patients from 1996 to 2002 with known lung cancer or abnormal findings on chest radiography or computed tomography (N=2618). Patients with adenocarcinoma or squamous cell, small-cell, or large-cell carcinoma were included in the study. Data were collected on patient sex, age, cancer type, stage at diagnosis, and survival status.

RESULTS

A total of 1216 men and 997 women met inclusion criteria for the study. There was no significant difference in age between sexes at diagnosis. Women were significantly more likely to have adenocarcinoma or small-cell carcinoma but less likely to have squamous cell carcinoma compared with men. There were no significant differences between sexes in the incidence of large-cell carcinoma. No significant differences were found between men and women in terms of cancer stage at diagnosis. There were significant differences in survival between the histologic types at years 3, 4, and 5. Only patients with stage I disease showed a difference between sexes and only for years 2, 3, 4, and 5.

CONCLUSION

Overall differences in lung cancer histology and survival were found between men and women. Because a high mortality rate of lung cancer exists in both sexes, it is important to understand its occurrence and survival rates in both sexes.

Coronary artery bypass graft surgery outcomes among African-Americans and Caucasian patients

There have been few studies to date that investigate the effect of race on outcomes related to coronary artery bypass grafting. The objective of the present study was to investigate race as an independent predictor of outcomes among patients undergoing coronary artery bypass graft (CABG). A nested case-control study from a twelve-year hospitalization cohort (N=9671) in which data were collected prospectively was conducted. Cases were African-American patients undergoing CABG (N=644). Controls were randomly selected Caucasian patients undergoing CABG (N=1932). Controls were matched to cases 3:1 on year of surgery. Fifteen preoperative and intraoperative risk factors and 14 outcomes were examined. The 14 outcomes of interest were length of stay, readmission to ICU, total ICU stay, total hours on ventilator post-op, reoperation for bleeding/tamponade, deep sternal wound infection, neurological complications, pneumonia, other pulmonary complications, renal failure, gastrointestinal complications, atrial fibrillation requiring treatment, in-hospital mortality, and intraoperative complications. Regression analysis was used to control for risk factors. Multivariate analysis revealed African-Americans were at greater risk for renal complications (OR 1.88, 95% CI 1.27-2.77), neurological complications (OR 1.34, 95% CI 1.01-1.77), and pulmonary complications (OR 2.11, 95% CI 1.72-2.59). African Americans had a significantly longer hospitalization post-operatively (OR 0.79, 95% CI 0.66-0.96), but were less likely to experience post-operative atrial fibrillation requiring treatment than Caucasians (OR 0.64, 95% CI 0.49-0.84). Even after multiple adjustments, African-Americans undergoing CABG surgery had significantly greater morbidity compared to Caucasian patients.

Replacement of the Descending Aorta using the daVinci Surgical System in a Sheep Model: Comparison of Anastomosis Techniques

OBJECTIVE

The purpose of our study was to assess the feasibility of a closed-chest replacement of the descending thoracic aorta utilizing the daVinci surgical robotic system and to compare hand-sewn running anastomosis to interrupted nitinol clips (Coalescent Surgical).

METHODS

Six sheep underwent replacement of the descending aorta using Intuitive's daVinci surgical system. Using the daVinci, the descending aorta was dissected out and individual intercostal arteries were clipped and divided. Following systemic heparinization, the aorta was occluded using percutaneous vascular clamps (Chitwood clamps). The descending aorta was excised and replaced with a woven graft. The proximal and distal anastomoses were varied in each animal between a running 4-0 polypropylene technique and interrupted nitinol clips. Anastomoses were inspected for hemostasis and tested for burst strength.

RESULTS

Five of six animals survived the procedure. The average procedure time was 93 minutes. Cross-clamp times range from 55 to 25 minutes (average of 37 minutes). There was no significant difference in time between U-clip anastomoses (17 +/- 4.8 minutes) and sutured anastomoses (10.6 +/- 3.1 minutes). The burst pressure was higher for sutured anastomosis than for U-clips (214.6 +/- 61 and 110 +/- 35, respectively).

CONCLUSION

Replacement of the descending aorta with a graft is feasible in a closed chest model utilizing Intuitive's daVinci surgical system. While mean burst strengths were higher with a running sutured anastomosis, there was no difference in anastomotic time or ultimate hemostasis between techniques.

Level of education and patient opinion: significant differences in perceptions of health care

BACKGROUND

As part of the general competencies set forth by the Accreditation Council for Graduate Medical Education (ACGME), residents must have an understanding of systems-based practice, which is demonstrated by an awareness of-and responsiveness to-the comprehensive health care system. Residents must be able to effectively access and use system resources to provide care that is of optimal value. Essential to understanding and implementing systems-based practice is an awareness of how different patient populations perceive health care; one key factor that influences patients' perceptions of health care is their level of education.

METHODS

We surveyed 2900 adult patients in the Cincinnati, Ohio area and stratified them into 2 groups based on their level of education. Group 1 included patients with some high school education or a high school degree. Group 2 included patients with some college education, an undergraduate degree, or graduate/professional-level coursework. We then compared the groups' perceptions of common health care issues, including physician compensation, patient obligation for medical bills, and increased cost for the freedom to choose a physician.

RESULTS

Of 395 respondents, a higher percentage of Group 2 patients, compared with those in Group 1, understood that physicians do not collect 100% of what they bill (p < 0.001) and that businesses do influence the amount a physician is paid by insurance companies (p = 0.009). Conversely, a higher percentage of Group 1 patients thought that physicians are overpaid (p = 0.030) and that they keep a large portion of what they charge (p < 0.001). Further, fewer Group 1 respondents felt obligated to pay medical bills not covered by insurance (p = 0.002); they also were less willing to pay more for better medical care (p = 0.002) or for the freedom to choose a physician (p = 0.015).

CONCLUSIONS

This study indicates that patients with a lower level of education believe that physicians are overpaid and that they keep a large portion of insurance reimbursement. These findings may explain why fewer patients in this group feel that they are obligated to pay medical bills not covered by insurance and why they are less likely to pay more for better medical care or for the freedom to choose a physician.

Coronary artery bypass grafting in patients with dialysis-dependent end stage renal disease: a prospective, nested case-control study

OBJECTIVE

To assess if coronary artery bypass grafting (CABG) patients with dialysis-dependent end stage renal disease (ESRD) experience greater intraoperative and postoperative morbidity and mortality compared to CABG patients without ESRD.

METHODS

We conducted a nested case-control study from an 8-year hospitalization cohort in which data were collected prospectively. Inclusion criteria included CABG surgery and age greater than 18 years. Cases were patients with dialysis dependent ESRD (N = 28) and controls were patients without ESRD (N = 84). Cases were matched to controls 1:3 on age, gender, tobacco history, and New York Heart Association Functional Class. The outcomes of interest were mortality, intensive care unit length of stay, total length of hospitalization, time on the ventilator, wound complications, pulmonary complications, neurological complications, gastrointestinal complications, arrhythmia, and intraoperative complications. Using logistic regression we controlled for 13 potential confounding variables.

RESULTS

There were no significant differences between the groups with the exception of total length of hospitalization. Patients with dialysis-dependent ESRD had a significantly longer total hospitalization stay (21%) than patients without ESRD. There were no significant differences for the remaining nine outcomes of interest, including perioperative morbidity or mortality.

CONCLUSION

Intraoperative and postoperative morbidity and mortality for CABG were not increased for patients with dialysis-dependent ESRD compared to patients without ESRD. However, patients on dialysis undergoing CABG experienced a greater length of hospitalization than patients undergoing CABG who were not on dialysis.

Predictors and outcomes of gastrointestinal complications in patients undergoing coronary artery bypass graft surgery: A prospective, nested case-control study1 1No competing interests declared

BACKGROUND

The aim of this study was to assess risk factors and outcomes of gastrointestinal (GI) complications in patients undergoing coronary artery bypass surgery (CABG).

STUDY DESIGN

We conducted a nested case-control study from a 9-year hospitalization cohort (n = 7,345) in which data were collected prospectively. Patients developed GI complications (n = 66) and controls did not (n = 330). Cases were matched to controls 1:5 on type of surgery. We examined 16 risk factors and 14 outcomes.

RESULTS

Five risk factors proved significant in predicting GI complications. Patients were more likely to be older than age 70, to be on dialysis, to have left ventricular hypertrophy, and to be on anticoagulants; the procedure was also more likely to be urgent. There was no significant difference between the cases and controls for the remaining 11 risk factors. We also computed correlation coefficients among the significant variables; using regression analysis, we found that patients undergoing CABG had a threefold increase in the risk of GI complications if they were older than age 70 (odds ratio [OR] 1.06, 95% CI 1.03 to 0.97), if they were on dialysis (OR 1.87, 95% CI 1.98 to 1.22), and if their procedure was urgent (OR 1.91, 95% CI 1.07 to 3.4). Eleven outcomes proved significant. Patients with GI complications ran a greater risk of mortality; required more additional procedures; suffered arrhythmia that required treatment; and were more likely to have neurologic, pulmonary, renal, and sternal wound complications. They also had greater length of hospitalization, intensive care unit length of hospitalization, ventilator time, and postoperative creatine phosphokinase levels.

CONCLUSIONS

In patients undergoing CABG surgery, urgency of the procedure, age greater than 70 years, and dialysis all significantly increased the risk of a GI complication. Patients with GI complications also experienced more negative outcomes.

Human monoclonal antibodies isolated from type I diabetes patients define multiple epitopes in the protein tyrosine phosphatase-like IA-2 antigen

Protein tyrosine phosphatase-like IA-2 autoantigen is one of the major targets of humoral autoimmunity in patients with insulin-dependant diabetes mellitus (IDDM). In an effort to define the epitopes recognized by autoantibodies against IA-2, we generated five human mAbs (hAbs) from peripheral B lymphocytes isolated from patients most of whom had been recently diagnosed for IDDM. Determination and fine mapping of the critical regions for autoantibody binding was performed by RIA using mutant and chimeric constructs of IA-2- and IA-2beta-regions. Four of the five IgG autoantibodies recognized distinct epitopes within the protein tyrosine phosphatase (PTP)-like domain of IA-2. The minimal region required for binding by three of the PTP-like domain-specific hAbs could be located to aa 777-979. Two of these hAbs cross-reacted with the related IA-2beta PTP-like domain (IA-2beta aa 741-1033). A further PTP-like domain specific hAb required the entire PTP-like domain (aa 687-979) for binding, but critical amino acids clustered in the N-terminal region 687-777. An additional epitope could be localized within the juxtamembrane domain (aa 603-779). In competition experiments, the epitope recognized by one of the hAbs was shown to be targeted by 10 of 14 anti-IA-2-positive sera. Nucleotide sequence analysis of this hAb revealed that it used a V(H) germline gene (DP-71) preferably expressed in autoantibodies associated with IDDM. The presence of somatic mutations in both heavy and light chain genes and the high affinity or this Ab suggest that the immune response to IA-2 is Ag driven.

CD8+ T cells are crucial for the ability of congenic normal mice to reject highly immunogenic sarcomas induced in nude mice with 3-methylcholanthrene

An attempt was made to identify the selection pressures put upon a growing tumour by CD8+ T cells. To this end tumours induced with 3-methylcholanthrene in T cell-deficient nude mice and in congenic T cell-competent nu/+ mice were transplanted to nu/+ recipients. The rejection rate of the sarcomas from nude mice was almost twice that of the sarcomas from nu/+ mice. Depletion of CD8+ T cells from nu/+ recipients prior to transplantation made them accept nude tumours that were consistently rejected by untreated nu/+ recipients. These findings suggest that a methylcholanthrene sarcoma during its growth in a T cell-competent host adapts to the T cell system through a selective elimination of highly immunogenic tumour cells that are susceptible to CD8+ T cell-mediated lysis.

The role of cytotoxic T-lymphocytes in the prevention and immune surveillance of tumors--lessons from normal and immunodeficient mice

The idea of immunological surveillance against cancer has existed for nearly 100 years but as no conclusive evidence has yet been published the importance of the cellular immune defense in the detection and removal of incipient or existing tumors is still a hotly debated subject. However, in order to select a relevant immunotherapeutic strategy in the treatment of cancer, a fundamental understanding of the basic immunologic conditions under which a tumor develops and exists is a prerequisite. Therefore, a murine model was set up that we hoped would enable us to confirm or reject the theory of immunological surveillance. A large panel of methylcholanthrene induced tumors was established in T-cell immunodeficient nude mice and congenic normal mice to study the influence of the immune system on developing tumors. As nude mice developed tumors fastest and with the highest incidence, we concluded that in this model the immune system constituted a 'tumor-suppressive factor' delaying and sometimes abrogating tumor growth, i.e. performing immune surveillance. Immunogenicity of the tumors was assessed by transplantation back to normal histocompatible mice. Tumors originating from the immunodeficient nude mice turned out to be far more immunogenic than tumors from normal mice, resulting in a high rejection rate. CD8+ cytotoxic T cells were found to be indispensable for this rejection, leading to the conclusion that the cytotoxic T cells perform immune selection in normal mice, eliminating immunogenic tumor cell variants in the incipient tumor. In this review, we discuss the difficulties facing immunotherapy when conclusions are drawn from the presented observations and hypotheses.

Risk and clearance of GB virus C/hepatitis G virus infection in homosexual men: A longitudinal study

The risk and clearance of GB virus type C (GBV-C)/hepatitis G virus (HGV) infection was investigated in a cohort of homosexual men (n=180; median follow-up time, 7 years). The interaction between GBV-C/HGV RNA and antibodies against the E2 region of the virus, and the clinical impact of chronic GBV-C/HGV infection were studied. GBV-C/HGV RNA was detected by RT-PCR, and E2 antibodies were assessed by an immunoassay. At baseline, 63% of the participants had evidence of previous or current GBV-C/HGV infection. The GBV-C/HGV incidence rate was 2 per 100 person-years (95% confidence interval 0. 9-3.8) and was similar to the HIV incidence. The incidence of GBV-C/HGV infection was significantly higher in those reporting unprotected anal intercourse (3.6 per 100 person-years compared to 0 in the group without such sexual contacts). The occurrence of E2 antibodies was strongly associated with GBV-C/HGV RNA clearance. A loss of E2 antibodies was observed at a rate of 1.5 per 100 person-years. It was higher among HIV-infected individuals. Chronic GBV-C/HGV infection was not associated with clinical or biochemical evidence of liver disease.

Cloning and functional expression of the D-beta-hydroxybutyrate dehydrogenase gene of Rhodobacter sp. DSMZ 12077

Nucleotide sequence and biochemical analysis of D-beta-hydroxybutyrate dehydrogenase (EC 1.1.1.30), isolated from Rhodobacter sp., indicate functional oligomers composed of subunits of 257 amino acids with a calculated M(r) of 26,800 and a pI of 5.90. Compared to mammalian short-chain alcohol dehydrogenases, the bacterial enzyme lacks a C-terminal lipid anchor domain and was found to be highly active upon expression in Escherichia coli even without lipid supplement. The recombinant enzyme could be highly enriched using a single chromatography step and was shown to be stable over a broad range of pH and temperature.

Risk and clearance of GB virus C/hepatitis G virus infection in homosexual men: A longitudinal study

The risk and clearance of GB virus type C (GBV-C)/hepatitis G virus (HGV) infection was investigated in a cohort of homosexual men (n=180; median follow-up time, 7 years). The interaction between GBV-C/HGV RNA and antibodies against the E2 region of the virus, and the clinical impact of chronic GBV-C/HGV infection were studied. GBV-C/HGV RNA was detected by RT-PCR, and E2 antibodies were assessed by an immunoassay. At baseline, 63% of the participants had evidence of previous or current GBV-C/HGV infection. The GBV-C/HGV incidence rate was 2 per 100 person-years (95% confidence interval 0. 9-3.8) and was similar to the HIV incidence. The incidence of GBV-C/HGV infection was significantly higher in those reporting unprotected anal intercourse (3.6 per 100 person-years compared to 0 in the group without such sexual contacts). The occurrence of E2 antibodies was strongly associated with GBV-C/HGV RNA clearance. A loss of E2 antibodies was observed at a rate of 1.5 per 100 person-years. It was higher among HIV-infected individuals. Chronic GBV-C/HGV infection was not associated with clinical or biochemical evidence of liver disease.

Inhibition of protein phosphatase 2A induces serine/threonine phosphorylation, subcellular redistribution, and functional inhibition of STAT3

Signal transducers and activators of transcription (STATs) are rapidly phosphorylated on tyrosine residues in response to cytokine and growth factor stimulation of cell surface receptors. STATs hereafter are translocated to the nucleus where they act as transcription factors. Recent reports suggest that serine phosphorylation of STATs also is involved in the regulation of STAT-mediated gene transcription. Here, we studied the role of serine/threonine phosphatases in STAT3 signaling in human antigen-specific CD4(+) T cell lines and cutaneous T cell lymphoma lines, expressing a constitutively activated STAT3. We show that an inhibitor of protein phosphatases (PPs) PP1/PP2A, calyculin A, induces (i) phosphorylation of STAT3 on serine and threonine residues, (ii) inhibition of STAT3 tyrosine phosphorylation and DNA binding activity, and (iii) relocation of STAT3 from the nucleus to the cytoplasm. Similar results were obtained with other PP2A inhibitors (okadaic acid, endothall thioanhydride) but not with inhibitors of PP1 (tautomycin) or PP2B (cyclosporine A). Pretreatment with the broad serine/threonine kinase inhibitor staurosporine partly blocked the calyculin A-induced STAT3 phosphorylation, whereas inhibitors of serine/threonine kinases, such as mitogen-activated protein kinase-1 extracellular-regulated kinase-kinase, mitogen-activated protein p38 kinase, and phosphatidylinositol 3-kinase, did not. In conclusion, we provide evidence that PP2A plays a crucial role in the regulation of STAT3 phosphorylation and subcellular distribution in T cells. Moreover, our findings suggest that the level of STAT3 phosphorylation is balanced between a staurosporine-sensitive kinase(s) and PP2A.

High MHC class I expression correlates with slow growth in UV-induced skin carcinomas in hairless mice

An experiment was set up to investigate the relationship, if any, between cell surface MHC class I expression and the growth rate for skin tumors induced by two different UV radiation regimens in hairless mice. Two groups of 20 hairless mice were each irradiated with either a UVA radiation source (2 SED per session) or broad-spectrum UV radiation (UVB) (8.1 SED per session) 5 days a week during the entire experiment. In the UVA group, 17 out of 20 animals developed tumors, and 10 of these grew to a diameter of > or = 5 mm. In the UVB group, 19 out of 20 animals developed tumors, and 15 of these grew to a diameter of > or = 5 mm. The tumor induction time, i.e. the time from the start of UV treatment to tumor appearance, was found to be significantly longer (p<0.01) in the UVA than in the UVB group. This is in accordance with previous findings. Of the 25 tumors growing to a diameter of > or = 5 mm, 11 were established as cultured cell lines (4 UVA and 7 UVB tumors). These uncloned cell lines were analyzed for surface expression of major histocompatibility complex class I by FACS analysis. There was a clear correlation between high MHC class I expression and slow growth of the individual tumors (p<0.05). This suggests a role for the MHC class I governed, i.e. cytotoxic T-cell-mediated, reactions in deciding the fate of UV-induced skin cancers. No correlation was found between MHC class I expression and tumor induction time.

Evolution of hepatitis G virus infection and antibody response to envelope protein in patients with transfusion-associated non-A, non-B hepatitis

The clinical significance and course of acute hepatitis G virus (HGV) infection were studied by measuring HGV RNA and antibody to HGV envelope protein E2 (HGV-E2 antibody). A total of 59 patients with transfusion-associated non-A, non-B hepatitis, who were followed-up for more than 1 year, were selected retrospectively. HGV RNA was measured by reverse transcriptase (RT) and nested polymerase chain reaction (PCR) was performed, using primer sets, in the 5'-non-coding region of the HGV genome. HGV-E2 antibody was measured by enzyme-linked immunosorbent assay (ELISA) using recombinant E2 protein. Of the 59 patients, 51 (86%) were infected with hepatitis C virus (HCV) and 12 (20%) were infected with HGV; 11 of the 12 with HGV infection were also infected with HCV. HGV viraemia was cleared during the follow-up period in seven of the 12 patients with HGV infection. All these seven patients seroconverted for HGV-E2 antibody just before or just after the clearance of HGV viraemia. In contrast, all five patients without clearance of HGV viraemia were negative for HGV-E2 antibody (P = 0.0013). Of seven patients with continuous HGV viraemia at 1 year from the onset of acute hepatitis, four with HCV RNA showed chronic elevation of alanine aminotransferase (ALT) but three without HCV RNA did not. The severity of acute hepatitis was similar between patients with both HGV and HCV infections and in those with HCV infection alone. The majority of patients with HGV infection cleared the virus during long-term follow-up. Appearance of HGV-E2 antibody was associated with the clearance of HGV viraemia. An abnormal ALT level was noted to depend on HCV infection but not on HGV infection in both the acute and chronic phases of transfusion-associated hepatitis.

Identification of hepatitis G virus particles in human serum by E2-specific monoclonal antibodies generated by DNA immunization

In order to elucidate the structure and morphology of hepatitis G virus (HGV), a recently isolated flavivirus, we generated a panel of eight monoclonal antibodies (MAbs) against the putative second envelope protein (E2) following DNA immunization. The MAbs were shown to be specific for four different epitopes on recombinant E2. MAb Mc6 was the only antibody able to detect the linear epitope LTGGFYEPL. In addition, Mc6 was able to immunoprecipitate viral particles in human blood samples as detected by reverse transcription-PCR amplification of HGV RNA. This precipitation could be competed by addition of saturating amounts of the linear peptide or abolished by addition of Nonidet P-40. We conclude that, albeit lacking the N-terminal sequence of a functional core protein, HGV builds classical viral particles displaying E2 envelope protein on their outer surfaces.

Past and present hepatitis G virus infections in areas where hepatitis C is highly endemic and those where it is not endemic

We reported previously on an area in Japan where over 30% of the inhabitants were positive for hepatitis C virus (HCV) antibody. In the present study, clinical features of hepatitis G virus (HGV) infection in this area of high endemicity were compared to those in an area where HCV is not endemic. A total of 400 individuals were selected randomly from those who were medically screened for liver disease in 1993; 200 were from the high-endemicity area, and the other 200 were from the no-endemicity area. HGV RNA was measured by reverse transcription and PCR with primers in the 5' noncoding region. Antibody to HGV envelope protein E2 was measured by an enzyme-linked immunosorbent assay. Prevalence of any HGV marker in the high-endemicity area (32%) was significantly (P < 0.0001) higher than that in the no-endemicity area (6%); similar differences, 32% versus 3% (P < 0.0001), had been observed for HCV markers (HCV RNA and HCV antibody). In areas of both high and no endemicity, HCV markers were significantly more prevalent in individuals with any HGV marker than in those without HGV markers, and age-specific prevalence of HGV markers was distributed similarly to that of any HCV marker. Among possible routes of HGV transmission that were analyzed, folk medicine was significant in the high-endemicity area, but blood transfusion was the major route in the no-endemicity area. The rate of accompanying viremia in HGV infection (15%) was significantly lower than that in HCV infection (78%) (P < 0.0001). In conclusion, HGV infection was highly prevalent in the area of high HCV endemicity and was closely associated with HCV infection. HGV seemed to be transmitted via the practice of folk medicine as well as blood transfusion. HGV resulted in a chronic carrier state less frequently than did HCV.

Confocal laser scanning microscopy of tumor/vessel relationship in xenografts in nude and scid mice

Using confocal laser scanning microscopy we studied sections of the T24B, a human bladder carcinoma, grown in C.B.-17 scid/scid or NMRI nu/nu mice in order to examine the relationship between tumor tissue and tumor vessels. Tumor cells were labelled with FITC-anti-cytokeratin and blood vessel endothelia with Cy3-labelled BS-I lectin. In contrast to our expectation, no major leaks in the endothelial lining of blood vessels were observed. We are looking for a suitable marker for mouse lymphatics in order to investigate their possible role.

Humoral immune response to the E2 protein of hepatitis G virus is associated with long-term recovery from infection and reveals a high frequency of hepatitis G virus exposure among healthy blood donors

The second envelope protein (E2) of the hepatitis G virus (HGV) was expressed in Chinese hamster ovary (CHO) cells and showed a molecular weight of approximately 60 to 70 kd, with 15 to 25 kd of the size contributed by N-linked glycosylation. An enzyme-linked immunosorbent assay (ELISA) using HGV-E2 was developed to test for antibodies to this protein (anti-E2) in human sera. High sensitivity was achieved by developing monoclonal antibodies (mAbs) to HGV-E2, which were used as capture antibodies in the ELISA. Our studies revealed that 16% of healthy Spanish blood donors were exposed to HGV, indicating that additional routes of viral transmission besides parenteral exposure might exist. An even higher prevalence of exposure to HGV (52%-73%) was found in several groups at risk of parenteral exposure to infectious agents, i.e., intravenous drug users, transfusion history, hemophiliacs, and hepatitis C virus (HCV)-positive patients. Most anti-E2-positive patients were HGV-RNA-negative and vice versa, indicating an inverse correlation of these two viral markers. A panel of 16 posttransfusion patients followed for up to 16 years revealed that patients who develop an anti-E2 response become HGV-RNA-negative, while patients who do not develop anti-E2 are persistently infected. Immunity to HGV seems to be long-lasting, because circulating antibody to E2 could still be detected 14 years after seroconversion. Sequence comparisons showed that E2 is highly conserved among isolates collected worldwide, indicating that immune escape variants are not common in HGV infections. This reflects on a molecular level why HGV infections usually are cleared spontaneously by the host. However, possible mechanisms of HGV persistence, as found in some patients, remain to be elucidated.

Interferon-gamma-induced MHC class I expression and defects in Jak/Stat signalling in methylcholanthrene-induced sarcomas

Seventy-eight uncloned tumour cell lines, each established from a primary sarcoma induced with methyl-cholanthrene in immunocompetent nu/+ BALB/c and C.B.-17 mice or in immunodeficient nu/nu BALB/c and severe combined immunodeficient (SCID) mice, were examined for sensitivity to interferon-gamma (IFN-gamma) as measured by tumour cell augmentation of major histocompatibility complex (MHC) class I expression. The tumour cells were cultured with IFN-gamma and their expression of Kd, Dd and Ld was measured by fluorescence-activated cell sorter analysis. All but three of the 78 tumour lines up-regulated Kd, Dd and Ld to a variable degree in response to IFN-gamma, indicating that IFN-gamma resistance is not a common property of these sarcomas. The tumour cell lines varied greatly in their MHC class I expression before as well as after IFN-gamma stimulation. There was a tendency towards a higher MHC expression after IFN-gamma stimulation in tumour lines from immunocompetent mice compared to immunodeficient mice, but no common maximum MHC class I expression level was found for the 78 tumour cell lines. Three of the tumour lines, all from immunodeficient mice, completely failed to respond to IFN-gamma by up-regulating MHC class I expression. The same three also displayed absence of IFN-gamma-induced Stat1 beta tyrosine phosphorylation and low Stat1 alpha tyrosine phosphorylation, indicating a defect in the signal transduction pathway affecting phosphorylation of Stat1. These findings strongly suggest a link between defects in Stat1 phosphorylation and the failure to up-regulate MHC class I. In all tumour lines tested, the Stat1 Western blotting revealed a 78 kDa protein (p78) not previously described.