The interaction between pre-admission β-blocker therapy, the Revised Cardiac Risk Index, and mortality in geriatric hip fracture patients

BACKGROUND

An association between β-blocker (BB) therapy and a reduced risk of major cardiac events and mortality in patients undergoing surgery for hip fractures has previously been demonstrated. Furthermore, a relationship between an increased Revised Cardiac Risk Index (RCRI) score and a higher risk of postoperative mortality has also been detected. The purpose of the current study was to investigate the interaction between BB therapy and RCRI in relation to 30-day postoperative mortality in geriatric patients after hip fracture surgery.

METHODS

All patients older than 65 years who underwent primary emergency hip fracture surgery in Sweden between January 1, 2008, and December 31, 2017, except for pathological fractures, were included in this retrospective cohort study. Patients were divided into cohorts based on their RCRI score (RCRI 1, 2, 3, and ≥4) and whether they had ongoing BB therapy at the time of admission. A Poisson regression model with robust standard errors of variance was used, while adjusting for confounders, to evaluate the association between BB therapy, RCRI, and 30-day mortality.

RESULTS

A total of 126,934 cases met the study inclusion criteria. β-Blocker therapy was associated with a 65% decrease in the risk of 30-day postoperative mortality in the whole study population (adjusted incidence rate ratio [95% confidence interval], 0.35 [0.32-0.38]; p < 0.001). The use of BB also resulted in a significant reduction in 30-day postoperative mortality within all RCRI cohorts. However, the most pronounced effect of BB therapy was seen in patients with an RCRI score greater than 0.

CONCLUSION

β-Blocker therapy is associated with a reduction in 30-day postoperative mortality, irrespective of RCRI score. Furthermore, patients with an elevated cardiac risk appear to have a greater benefit of BB therapy.

LEVEL OF EVIDENCE

Therapeutic/care management, level II.

Postoperative mortality in hip fracture patients stratified by the Revised Cardiac Risk Index: a Swedish nationwide retrospective cohort study

Objectives

The Revised Cardiac Risk Index (RCRI) is a tool that can be used to evaluate the 30-day risk of postoperative myocardial infarction, cardiac arrest and mortality. This study aims to confirm its association with postoperative mortality in patients who underwent hip fracture surgery.

Methods

All adults who underwent primary emergency hip fracture surgery in Sweden between January 1, 2008 and December 31, 2017 were included in this study. The database was retrieved by cross-referencing the Swedish National Quality Register for hip fractures with the Swedish National Board of Health and Welfare registers. The outcomes of interest were the association between the RCRI score and mortality at 30 days, 90 days and 1 year postoperatively.

Results

134 915 cases were included in the current study. There was a statistically significant linear trend in postoperative mortality with increasing RCRI scores at 30 days, 90 days and 1 year. An RCRI score ≥4 was associated with a 3.1 times greater risk of 30-day postoperative mortality (adjusted incidence rate ratio (IRR) 3.13, p<0.001), a 2.5 times greater risk of 90-day postoperative mortality (adjusted IRR 2.54, p<0.001) and a 2.8 times greater risk of 1-year postoperative mortality (adjusted HR 2.81, p<0.001) compared with that observed with an RCRI score of 0.

Conclusion

An increasing RCRI score is strongly associated with an elevated risk 30-day, 90-day and 1-year postoperative mortality after primary hip fracture surgery. The objective and easily retrievable nature of the variables included in the RCRI calculation makes it an appealing choice for risk stratification in the clinical setting.

Levels of evidence

Level III.

Beta-Blocker Therapy Is Associated With Increased 1-Year Survival After Hip Fracture Surgery: A Retrospective Cohort Study

The high mortality rates seen within the first postoperative year after hip fracture surgery have remained relatively unchanged in many countries for the past 15 years. Recent investigations have shown an association between beta-blocker (BB) therapy and a reduction in risk-adjusted mortality within the first 90 days after hip fracture surgery. We hypothesized that preoperative, and continuous postoperative, BB therapy may also be associated with a decrease in mortality within the first year after hip fracture surgery.

Statin therapy and postoperative short-term mortality after rectal cancer surgery

AIM

This study aimed to assess the correlation between regular statin therapy and postoperative mortality following surgical resection for rectal cancer.

METHOD

This retrospective cohort study included all adult patients undergoing abdominal rectal cancer surgery in Sweden between January 2007 and September 2016. Data were gathered from the Swedish Colorectal Cancer Registry, a large population-based prospectively collected registry. Statin users were defined as patients with one or more collected prescriptions of a statin within 12 months before the date of surgery. The statin-positive and statin-negative cohorts were matched by propensity scores based on baseline demographics.

RESULTS

A total of 11 966 patients underwent surgical resection for rectal cancer, of whom 3019 (25%) were identified as statin users. After applying propensity score matching (1:1), 3017 pairs were available for comparison. In the matched groups, statin users demonstrated reduced 90-day all-cause mortality (0.7% vs. 5.5%, p < 0.001) and also showed significantly reduced cause-specific mortality due to cardiovascular and respiratory events, as well as sepsis and multiorgan failure. The significant postoperative survival benefit of statin users was seen despite a higher rate of cardiovascular comorbidity.

CONCLUSION

Preoperative statin therapy displays a strong association with reduced postoperative mortality following surgical resection for rectal cancer. The results from the current study warrant further investigation to determine whether a causal relationship exists.

The mortality burden in patients with hip fractures and dementia

Purpose

Dementia is strongly associated with postoperative death in patients subjected to hip fracture surgery. Nevertheless, there is a distinct lack of research investigating the cause of postoperative mortality in patients with dementia. This study aims to investigate the distribution and the risk of cause-specific postoperative mortality in patients with dementia compared to the general hip fracture population.

Methods

All adults who underwent emergency hip fracture surgery in Sweden between 1/1/2008 and 31/12/2017 were considered for inclusion. Pathological, conservatively managed fractures, and reoperations were excluded. The database was retrieved by cross-referencing the Swedish National Quality Registry for Hip Fracture patients with the Swedish National Board of Health and Welfare quality registers. A Poisson regression model was used to determine the association between dementia and all-cause as well as cause-specific 30-day postoperative mortality.

Results

134,915 cases met the inclusion criteria, of which 20% had dementia at the time of surgery. The adjusted risk of all-cause 30-day postoperative mortality was 67% higher in patients with dementia after hip fracture surgery compared to patients without dementia [adj. IRR (95% CI): 1.67 (1.60–1.75), p < 0.001]. The risk of cause-specific mortality was also higher in patients with dementia, with up to a sevenfold increase in the risk cerebrovascular mortality [adj. IRR (95% CI): 7.43 (4.99–11.07), p < 0.001].

Conclusions

Hip fracture patients with dementia have a higher risk of death in the first 30 days postoperatively, with a substantially higher risk of mortality due to cardiovascular, respiratory, and cerebrovascular events, compared to patients without dementia.

Bile duct clearance and cholecystectomy for choledocholithiasis: Definitive single-stage laparoscopic cholecystectomy with intraoperative endoscopic retrograde cholangiopancreatography versus staged procedures

BACKGROUND

Clinical equipoise exists regarding optimal sequencing in the definitive management of choledocholithiasis. Our current study compares sequential biliary ductal clearance and cholecystectomy at an interval to simultaneous laparoendoscopic management on index admission in a pragmatic retrospective manner.

METHODS

Records were reviewed for all patients admitted between January 2015 and December 2018 to a Swedish and an Irish university hospital. Both hospitals differ in their practice patterns for definitive management of choledocholithiasis. At the Swedish hospital, patients with choledocholithiasis underwent laparoscopic cholecystectomy with intraoperative rendezvous endoscopic retrograde cholangiopancreatography (ERCP) at index admission (one stage). In contrast, interval day-case laparoscopic cholecystectomy followed index admission ERCP (two stages) at the Irish hospital. Clinical characteristics, postprocedural complications, and inpatient duration were compared between cohorts.

RESULTS

Three hundred fifty-seven patients underwent treatment for choledocholithiasis during the study period, of whom 222 (62.2%) underwent a one-stage procedure in Sweden, while 135 (37.8%) underwent treatment in two stages in Ireland. Patients in both cohorts were closely matched in terms of age, sex, and preoperative serum total bilirubin. Patients in the one-stage group exhibited a greater inflammatory reaction on index admission (peak C-reactive protein, 136 ± 137 vs. 95 ± 102 mg/L; p = 0.024), had higher incidence of comorbidities (age-adjusted Charlson Comorbidity Index, ≥3; 37.8% vs. 20.0%; p = 0.003), and overall were less fit for surgery (American Society of Anesthesiologists, ≥3; 11.7% vs. 3.7%; p < 0.001). Despite this, a significantly shorter mean time to definitive treatment, that is, cholecystectomy (3.1 ± 2.5 vs. 40.3 ± 127 days, p = 0.017), without excess morbidity, was seen in the one-stage compared with the two-stage cohort. Patients in the one-stage cohort experienced shorter mean postprocedure length of stay (3.0 ± 4.7 vs. 5.0 ± 4.6 days, p < 0.001) and total length of hospital stay (6.5 ± 4.6 vs. 9.0 ± 7.3 days, p = 0.002). The only significant difference in postoperative complications between the cohorts was urinary retention, with a higher incidence in the one-stage cohort (19% vs. 1%, p = 0.004).

CONCLUSION

Where appropriate expertise and logistics exist within developing models of acute care surgery worldwide, consideration should be given to index-admission laparoscopic cholecystectomy with intraoperative ERCP for the treatment of choledocholithiasis. Our data suggest that this strategy significantly shortens the time to definitive treatment and decreases total hospital stay without any excess in adverse outcomes.

LEVEL OF EVIDENCE

Therapeutic/Care Management Level IV.

A nationwide observational cohort study of the relationship between beta-blockade and survival after hip fracture surgery

PURPOSE

Despite advances in the care of hip fractures, this area of surgery is associated with high postoperative mortality. Downregulating circulating catecholamines, released as a response to traumatic injury and surgical trauma, is believed to reduce the risk of death in noncardiac surgical patients. This effect has not been studied in hip fractures. This study aims to assess whether survival benefits are gained by reducing the effects of the hyper-adrenergic state with beta-blocker therapy in patients undergoing emergency hip fracture surgery.

METHODS

This is a retrospective nationwide observational cohort study. All adults [Formula: see text] 18 years were identified from the prospectively collected national quality register for hip fractures in Sweden during a 10-year period. Pathological fractures were excluded. The cohort was subdivided into beta-blocker users and non-users. Poisson regression with robust standard errors and adjustments for confounders was used to evaluate 30-day mortality.

RESULTS

134,915 patients were included of whom 38.9% had ongoing beta-blocker therapy at the time of surgery. Beta-blocker users were significantly older and less fit for surgery. Crude 30-day all-cause mortality was significantly increased in non-users (10.0% versus 3.7%, p < 0.001). Beta-blocker therapy resulted in a 72% relative risk reduction in 30-day all-cause mortality (incidence rate ratio 0.28, 95% CI 0.26-0.29, p < 0.001) and was independently associated with a reduction in deaths of cardiovascular, respiratory, and cerebrovascular origin and deaths due to sepsis or multiorgan failure.

CONCLUSIONS

Beta-blockers are associated with significant survival benefits when undergoing emergency hip fracture surgery. Outlined results strongly encourage an interventional design to validate the observed relationship.

Pre-operative beta-blocker therapy does not affect short-term mortality after esophageal resection for cancer

BACKGROUND

It has been postulated that the hyperadrenergic state caused by surgical trauma is associated with worse outcomes and that β-blockade may improve overall outcome by downregulation of adrenergic activity. Esophageal resection is a surgical procedure with substantial risk for postoperative mortality. There is insufficient data to extrapolate the existing association between preoperative β-blockade and postoperative mortality to esophageal cancer surgery. This study assessed whether preoperative β-blocker therapy affects short-term postoperative mortality for patients undergoing esophageal cancer surgery.

METHODS

All patients with an esophageal cancer diagnosis that underwent surgical resection with curative intent from 2007 to 2017 were retrospectively identified from the Swedish National Register for Esophagus and Gastric Cancers (NREV). Patients were subdivided into β-blocker exposed and unexposed groups. Propensity score matching was carried out in a 1:1 ratio. The outcome of interest was 90-day postoperative mortality.

RESULTS

A total of 1466 patients met inclusion criteria, of whom 35% (n = 513) were on regular preoperative β-blocker therapy. Patients on β-blockers were significantly older, more comorbid and less fit for surgery based on their ASA score. After propensity score matching, 513 matched pairs were available for analysis. No difference in 90-day mortality was detected between β-blocker exposed and unexposed patients (6.0% vs. 6.6%, p = 0.798).

CONCLUSION

Preoperative β-blocker therapy is not associated with better short-term survival in patients subjected to curative esophageal tumor resection.

The association between the Revised Cardiac Risk Index and short-term mortality after hip fracture surgery

PURPOSE

The post-operative mortality after hip fracture surgery is high and has remained largely unchanged during the last decades. The Revised Cardiac Risk Index (RCRI) is a tool used to evaluate the 30-day risk of, among other outcomes, post-operative mortality. The aim of this study is to determine the association between the RCRI score and post-operative mortality in patients undergoing hip fracture surgery.

METHODS

Data was obtained from the national hip fracture register which was cross-referenced with patients' electronic hospital records. All adults who underwent primary emergency hip fracture surgery in Orebro County, Sweden, between January 1, 2013 and December 31, 2017, were included. Patients were divided into two cohorts: low RCRI (score = 0-1) and high RCRI (score ≥ 2). A Poisson regression model was employed to investigate the association between a high RCRI score and 30- and 90-day post-operative mortality.

RESULTS

A total of 2443 patients, of whom 446 (18%) had a high RCRI score, were included in the current study. When adjusting for age, sex, comorbidities and type of surgery, the incidence of 30-day mortality increased by 46% in the high RCRI cohort (adj. IRR 1.46, 95% CI, 1.10-1.94, p = 0.010). Similar results were observed for 90-day mortality (adj. IRR 1.50, 95% CI, 1.21-1.84, p < 0.001).

CONCLUSION

The RCRI is applicable to patients that undergo surgery for traumatic hip fractures. A high RCRI score is associated with an increased incidence of both 30- and 90-day post-operative mortality. Future studies to evaluate these findings are needed.

β-adrenergic blockade is associated with a reduced risk of 90-day mortality after surgery for hip fractures

Background

There is a significant postoperative mortality risk in patients subjected to surgery for hip fractures. Adrenergic hyperactivity induced by trauma and subsequent surgery is thought to be an important contributor. By downregulating the effect of circulating catecholamines the increased risk of postoperative mortality may be reduced. The aim of the current study is to assess the association between regular β-blocker therapy and postoperative mortality.

Methods

This cohort study used the prospectively collected Swedish National Quality Registry for hip fractures to identify all patients over 40 years of age subjected to surgery for hip fractures between 2013 and 2017 in Örebro County, Sweden. Patients with ongoing β-blocker therapy at the time of surgery were allocated to the β-blocker-positive cohort. The primary outcome of interest was 90-day postoperative mortality. Risk factors for 90-day mortality were evaluated using Poisson regression analysis.

Results

A total of 2443 patients were included in this cohort of whom 900 (36.8%) had ongoing β-blocker therapy before surgery. The β-blocker positive group was significantly older, less fit for surgery based on their American Society of Anesthesiologists classification and had a higher prevalence of comorbidities. A significant risk reduction in 90-day mortality was detected in patients receiving β-blockers (adjusted incidence rate ratio=0.82, 95% CI 0.68 to 0.98, p=0.03).

Conclusions

β-blocker therapy is associated with a significant reduction in 90-day postoperative mortality after hip fracture surgery. Further investigation into this finding is warranted.

Level of evidence

Therapeutic study, level III; prognostic study, level II.

Effects of beta-blocker therapy on mortality after elective colon cancer surgery: a Swedish nationwide cohort study

OBJECTIVE

Colon cancer surgery remains associated with substantial postoperative morbidity and mortality despite advances in surgical techniques and care. The trauma of surgery triggers adrenergic hyperactivation which drives adverse stress responses. We hypothesised that outcome benefits are gained by reducing the effects of hyperadrenergic activity with beta-blocker therapy in patients undergoing colon cancer surgery. This study aims to test this hypothesis.

DESIGN

Retrospective cohort study.

SETTING AND PARTICIPANTS

This is a nationwide study which includes all adult patients undergoing elective colon cancer surgery in Sweden over 10 years. Patient data were collected from the Swedish Colorectal Cancer Registry. The national drugs registry was used to obtain information about beta-blocker use. Patients were subdivided into exposed and unexposed groups. The association between beta-blockade, short-term and long-term mortality was evaluated using Poisson regression, Kaplan-Meier curves and Cox regression.

PRIMARY AND SECONDARY OUTCOMES

Primary outcome of interest was 1-year all-cause mortality. Secondary outcomes included 90-day all-cause and 5-year cancer-specific mortality.

RESULTS

The study included 22 337 patients of whom 36.1% were prescribed preoperative beta-blockers. Survival was higher in patients on beta-blockers up to 1 year after surgery despite this group being significantly older and of higher comorbidity. Regression analysis demonstrated significant reductions in 90-day deaths (IRR 0.29, 95% CI 0.24 to 0.35, p<0.001) and a 43% risk reduction in 1-year all-cause mortality (adjusted HR 0.57, 95% CI 0.52 to 0.63, p<0.001) in beta-blocked patients. In addition, cancer-specific mortality up to 5 years after surgery was reduced in beta-blocked patients (adjusted HR 0.80, 95% CI 0.73 to 0.88, p<0.001).

CONCLUSION

Preoperative beta-blockade is associated with significant reductions in postoperative short-term and long-term mortality following elective colon cancer surgery. Its potential prophylactic effect warrants further interventional studies to determine whether beta-blockade can be used as a way of improving outcomes for this patient group.

The statistical importance of P-POSSUM scores for predicting mortality after emergency laparotomy in geriatric patients

Background

Geriatric patients frequently undergo emergency general surgery and accrue a greater risk of postoperative complications and fatal outcomes than the general population. It is highly relevant to develop the most appropriate care measures and to guide patient-centered decision-making around end-of-life care.

Portsmouth - Physiological and Operative Severity Score for the enumeration of Mortality and morbidity (P-POSSUM) has been used to predict mortality in patients undergoing different types of surgery. In the present study, we aimed to evaluate the relative importance of the P-POSSUM score for predicting 90-day mortality in the elderly subjected to emergency laparotomy from statistical aspects.

Methods

One hundred and fifty-seven geriatric patients aged ≥65 years undergoing emergency laparotomy between January 1st, 2015 and December 31st, 2016 were included in the study. Mortality and 27 other patient characteristics were retrieved from the computerized records of Örebro University Hospital in Örebro, Sweden. Two supervised classification machine methods (logistic regression and random forest) were used to predict the 90-day mortality risk. Three scalers (Standard scaler, Robust scaler and Min-Max scaler) were used for variable engineering. The performance of the models was evaluated using accuracy, sensitivity, specificity and area under the receiver operating characteristic curve (AUC). Importance of the predictors were evaluated using permutation variable importance and Gini importance.

Results

The mean age of the included patients was 75.4 years (standard deviation =7.3 years) and the 90-day mortality rate was 29.3%. The most common indication for surgery was bowel obstruction occurring in 92 (58.6%) patients. Types of post-operative complications ranged between 7.0–36.9% with infection being the most common type. Both the logistic regression and random forest models showed satisfactory performance for predicting 90-day mortality risk in geriatric patients after emergency laparotomy, with AUCs of 0.88 and 0.93, respectively. Both models had an accuracy > 0.8 and a specificity ≥0.9. P-POSSUM had the greatest relative importance for predicting 90-day mortality in the logistic regression model and was the fifth important predictor in the random forest model. No notable change was found in sensitivity analysis using different variable engineering methods with P-POSSUM being among the five most accurate variables for mortality prediction.

Conclusion

P-POSSUM is important for predicting 90-day mortality after emergency laparotomy in geriatric patients. The logistic regression model and random forest model may have an accuracy of > 0.8 and an AUC around 0.9 for predicting 90-day mortality. Further validation of the variables’ importance and the models’ robustness is needed by use of larger dataset.

The Relationship Between Severe Complications, Beta-Blocker Therapy and Long-Term Survival Following Emergency Surgery for Colon Cancer

BACKGROUND

Emergency surgery for colon cancer carries significant morbidity, and studies show more than doubled mortality when comparing elective to emergency surgery. The relationship between postoperative complications and survival has been outlined. Beta-blocker therapy has been linked to improved postoperative outcomes. This study aims to assess the impact of postoperative complications on long-term survival following emergency surgery for colon cancer and to determine whether beta-blockade can reduce complications.

STUDY DESIGN

This cohort study utilized the prospective Swedish Colorectal Cancer Registry to identify adults undergoing emergency colon cancer surgery between 2011 and 2016. Prescription data for preoperative beta-blocker therapy were collected from the national drug registry. Cox regression was used to evaluate the effect of beta-blocker exposure and complications on 1-year mortality, and Poisson regression was used to evaluate beta-blocker exposure in patients with major complications.

RESULTS

A total of 3139 patients were included with a mean age of 73.1 [12.4] of which 671 (21.4%) were prescribed beta-blockers prior to surgery. Major complications occurred in 375 (11.9%) patients. Those suffering major complications showed a threefold increase in 1-year mortality (adjusted HR = 3.29; 95% CI 2.75-3.94; p < 0.001). Beta-blocker use was linked to a 60% risk reduction in 1-year mortality (adjusted HR = 0.40; 95% CI 0.26-0.62; p < 0.001) but did not show a statistically significant association with reductions in major complications (adjusted IRR = 0.77; 95% CI 0.59-1.00; p = 0.055).

CONCLUSION

The development of major complications after emergency colon cancer surgery is associated with increased mortality during one year after surgery. Beta-blocker therapy may protect against postoperative complications.

Beta-blocker Therapy is Associated with Decreased 1-year Mortality After Emergency Laparotomy in Geriatric Patients

Background and Aims:

Emergency laparotomy is associated with a great risk of mortality in the elderly. The hyperadrenergic state induced by surgical trauma may play an important role in the pathophysiology of this increased risk. Studies have shown that beta-blocker exposure may be associated with decreased morbidity and mortality in the perioperative period. We aimed to study the effect of beta-blocker on mortality in geriatric patients undergoing emergency laparotomy.

Material and Methods:

This is a retrospective study of patients who underwent emergency laparotomy between 1 January 2015 and 31 December 2016 at a single institution. The outcomes of interest were the association between post-operative complications and in-hospital and 1-year mortality in patients on beta-blocker therapy (BB(+)) and those who were not (BB(−)). The Poisson regression analysis was used to evaluate the association.

Results:

A total of 192 patients were included of whom 62 (32.2%) had pre-operative beta-blocker therapy with continued exposure during their hospital stay. The in-hospital mortality was 17.7% in the BB(+) and 23.8% in the BB(−) cohorts ( p = 0.441). One-year mortality was significantly lower in the BB(+) group compared to the BB(−) group (30.6% versus 47.7%; p = 0.038). After adjusting for confounders, the incidence of deaths during 1 year post-operatively decreased by 35% in the BB(+) group (incidence rate ratio = 0.65, p = 0.004). No significant differences in the incidence of post-operative complications between the two groups could be measured.

Conclusion:

Beta-blocker therapy may be associated with reduced 1-year mortality following emergency laparotomy in geriatric patients.

Effect of beta-blocker therapy on early mortality after emergency colonic cancer surgery

Background

Emergency colorectal cancer surgery is associated with significant mortality. Induced adrenergic hyperactivity is thought to be an important contributor. Downregulating the effects of circulating catecholamines may reduce the risk of adverse outcomes. This study assessed whether regular preoperative beta-blockade reduced mortality after emergency colonic cancer surgery.

Methods

This cohort study used the prospectively collected Swedish Colorectal Cancer Registry to recruit all adult patients requiring emergency colonic cancer surgery between 2011 and 2016. Patients were subdivided into those receiving regular beta-blocker therapy before surgery and those who were not (control). Demographics and clinical outcomes were compared. Risk factors for 30-day mortality were evaluated using Poisson regression analysis.

Results

A total of 3187 patients were included, of whom 685 (21·5 per cent) used regular beta-blocker therapy before surgery. The overall 30-day mortality rate was significantly reduced in the beta-blocker group compared with controls: 3·1 (95 per cent c.i. 1·9 to 4·7) versus 8·6 (7·6 to 9·8) per cent respectively (P &lt; 0·001). Beta-blocker therapy was the only modifiable protective factor identified in multivariable analysis of 30-day all-cause mortality (incidence rate ratio 0·31, 95 per cent c.i. 0·20 to 0·47; P &lt; 0·001) and was associated with a significant reduction in death of cardiovascular, respiratory, sepsis and multiple organ failure origin.

Conclusion

Preoperative beta-blocker therapy may be associated with a reduction in 30-day mortality following emergency colonic cancer surgery.

Simultaneous common bile duct clearance and laparoscopic cholecystectomy: experience of a one-stage approach

Introduction

The timing and optimal method for common bile duct (CBD) clearance and laparoscopic cholecystectomy remains controversial. Several different approaches are available in clinical practice. The current study presents the experience of two European hospitals of simultaneous laparoscopic cholecystectomy (LC) and intra-operative endoscopic retrograde cholangiopacreatography (IO-ERCP) done by surgeons.

Methods

Retrospective analysis of all consecutive patients subjected to LC + IO-ERCP during their index admission between 4/2014 and 9/2016. Data accrued included patient demographics, laboratory markers, operation time (min) reported as mean (± SD) and hospital length of stay (LOS) reported as median (lower quartile, upper quartile).

Results

During the 29-month study, a total of 201 consecutive LC + IO-ERCPs were performed. The mean age of patients was 55 ± 19 years and 67% were female. The mean intervention time was 105 ± 44 min. The total LOS was 4 (3,  7) days and the post-operative LOS was 2 (1,  3) days. A total of 6 (3%) patients experienced post-interventional pancreatitis and two (1%) patients suffered a Strasberg type A bile leak. All patients were successfully discharged.

Conclusion

Simultaneous LC + IO-ERCP is associated with few complications. Further studies investigating cost-benefit and patient satisfaction are warranted.

Does Beta-Blockade Reduce the Risk of Depression in Patients with Isolated Severe Extracranial Injuries?

Background

Approximately half of trauma patients develop post-traumatic depression. It is suggested that beta-blockade impairs trauma memory recollection, reducing depressive symptoms. This study investigates the effect of early beta-blockade on depression following severe traumatic injuries in patients without significant brain injury.

Methods

Patients were identified by retrospectively reviewing the trauma registry at an urban university hospital between 2007 and 2011. Severe extracranial injuries were defined as extracranial injuries with Abbreviated Injury Scale score ≥3, intracranial Abbreviated Injury Scale score <3 and an Injury Severity Score ≥16. In-hospital deaths and patients prescribed antidepressant therapy ≤1 year prior to admission were excluded. Patients were stratified into groups based on pre-admission beta-blocker status. The primary outcome was post-traumatic depression, defined as receiving antidepressants ≤1 year following trauma.

Results

Five hundred and ninety-six patients met the inclusion criteria with 11.4% prescribed pre-admission beta-blockade. Patients receiving beta-blockers were significantly older (57 ± 18 vs. 42 ± 17 years, p < 0.001) with lower Glasgow Coma Scale score (12 ± 3 vs. 14 ± 2, p < 0.001). The beta-blocked cohort spent significantly longer in hospital (21 ± 20 vs. 15 ± 17 days, p < 0.01) and intensive care (4 ± 7 vs. 3 ± 5 days, p = 0.01). A forward logistic regression model was applied and predicted lack of beta-blockade to be associated with increased risk of depression (OR 2.7, 95% CI 1.1–7.2, p = 0.04). After adjusting for group differences, patients lacking beta-blockers demonstrated an increased risk of depression (AOR 3.3, 95% CI 1.2–8.6, p = 0.02).

Conclusions

Pre-admission beta-blockade is associated with a significantly reduced risk of depression following severe traumatic injury. Further investigation is needed to determine the beneficial effects of beta-blockade in these instances.

Outcomes after resection versus non-resection management of penetrating grade III and IV pancreatic injury: A trauma quality improvement (TQIP) databank analysis

BACKGROUND

High-grade traumatic pancreatic injuries are associated with significant morbidity and mortality. Non-resection management is associated with fewer complications in pediatric patients. The present study evaluates outcomes following resection versus non-resection management of severe pancreatic injury caused by penetrating trauma.

METHODS

A retrospective study of the Trauma Quality Improvement Program (TQIP) database was performed from 1/2010 to 12/2014. Patients with AAST Organ Injury Scale pancreatic grade III and IV injuries caused by penetrating trauma were included in the study. Demographics, vital signs on admission, Abbreviated Injury Scale per body region, Injury Severity Score, transfusion and therapeutic modality were obtained. Mortality, length of stay (LOS), pseudocyst, pancreatitis, sepsis, thromboembolism, renal failure, ARDS and unplanned ICU admission or re-operation were stratified according to injury grade and treatment modality. Patients were stratified into those who did/did not undergo pancreatic resection.

RESULTS

A total of 4,098 patients had a pancreatic injury of which 15.9% (n=653) had a grade III and 6.7% (n=274) a grade IV pancreatic injury. There were no differences in patient demographics or overall injury severity between the resected and non-resected cohorts within each pancreatic injury grade. Forty-two percent of grade III and 38.0% of grade IV injuries underwent pancreatic resection. The total LOS was longer in the resection arm irrespective of pancreatic injury severity. There was no significant difference in morbidity between cohorts. Similarly, mortality was not significantly different between the two management approaches for grade III: 15.1% (95% CI 11.0-19.9) vs. 18.4% (95% CI 14.6-22.6), p=0.32 and grade IV: 24.0% (95% CI: 16.2-33.4) vs. 27.1% (95% CI: 20.5-34.4), p=0.68.

CONCLUSION

Resection for treatment of grade III and IV pancreatic injury is not associated with a significant decrease in mortality but is associated with an increase in hospital LOS.

Comparing Methodologies in a Series of Speech Outcome Studies

Background:

Development of the speech audit tool Cleft Audit Protocol for Speech Augmented (CAPS-A) facilitated intercenter comparison of speech outcomes following cleft palate repair. The CAPS-A protocol recommends consensus listening by 3 speech and language therapists, 2 of whom must be CAPS-A trained. Allowing 15 minutes per sample, 15 to 20 samples can be assessed each day. Centers typically have resources to audit 15 to 75 samples per year but not to report speech outcomes of larger data sets for research. This 3-phased outcome study examines how the implementation of the CAPS-A protocol might be modified without compromising reliability.

Methodology:

In phase 1, 2 external listeners independently rated 42 speech samples; in phase 2, 2 external listeners consensus listened 25% of 140 samples before 1 listener independently rated the remainder; phase 3 compared 124 Great Ormond Street Speech Assessment (GOS.SP.ASS’98) records from live assessments with CAPS-A-rated video samples.

Results:

Hypernasality, nasal airflow, and passive cleft speech characteristics were rated to identify signs of velopharyngeal dysfunction across all phases. Phase 1 demonstrated suboptimal correlation, intraclass correlation coefficient (ICC) ranging between 0.39 and 0.72. However, the “modified” CAPS-A consensus listening process in phase 2 achieved a mean ICC of 0.91. Phase 3 revealed only moderate agreement between GOS.SP.ASS’98 and CAPS-A.

Conclusion:

A large data set of speech samples was successfully managed by establishing good interrater reliability on 25% of the data, which calibrated the listeners and validated a decision for only 1 of 2 listeners to rate the remaining speech samples. The recommended implementation of the CAPS-A protocol can therefore be modified for more efficient speech outcome reporting.

β-Blocker after severe traumatic brain injury is associated with better long-term functional outcome: a matched case control study

PURPOSE

Severe traumatic brain injury (TBI) is the predominant cause of death and disability following trauma. Several studies have observed improved survival in TBI patients exposed to β-blockers, however, the effect on functional outcome is poorly documented.

METHODS

Adult patients with severe TBI (head AIS ≥ 3) were identified from a prospectively collected TBI database over a 5-year period. Patients with neurosurgical ICU length of stay <48 h and those dying within 48 h of admission were excluded. Patients exposed to β-blockers ≤ 48 h after admission and who continued with treatment until discharge constituted β-blocked cases and were matched to non β-blocked controls using propensity score matching. The outcome of interest was Glasgow Outcome Scores (GOS), as a measure of functional outcome up to 12 months after injury. GOS ≤ 3 was considered a poor outcome. Bivariate analysis was deployed to determine differences between groups. Odds ratio and 95% CI were used to assess the effect of β-blockers on GOS.

RESULTS

362 patients met the inclusion criteria with 21% receiving β-blockers during admission. After propensity matching, 76 matched pairs were available for analysis. There were no statistical differences in any variables included in the analysis. Mean hospital length of stay was shorter in the β-blocked cases (18.0 vs. 26.8 days, p < 0.01). The risk of poor long-term functional outcome was more than doubled in non-β-blocked controls (OR 2.44, 95% CI 1.01-6.03, p = 0.03).

CONCLUSION

Exposure to β-blockers in patients with severe TBI appears to improve functional outcome. Further prospective randomized trials are warranted.

Risk factors for depression following traumatic injury: An epidemiological study from a scandinavian trauma center

INTRODUCTION

A significant proportion of patients suffer depression following traumatic injuries. Once manifested, major depression is challenging to overcome and its presence risks impairing the potential for physical rehabilitation and functional recovery. Risk stratification for early detection and intervention in these instances is important. This study aims to investigate patient and injury characteristics associated with an increased risk for depression.

METHODS

All patients with traumatic injuries were recruited from the trauma registry of an urban university hospital between 2007 and 2012. Patient and injury characteristics as well as outcomes were collected for analysis. Patients under the age of eighteen, prescribed antidepressants within one year of admission, in-hospital deaths and deaths within 30days of trauma were excluded. Pre- and post-admission antidepressant data was requested from the national drugs registry. Post-traumatic depression was defined as the prescription of antidepressants within one year of trauma. To isolate independent risk factors for depression a multivariable forward stepwise logistic regression model was deployed.

RESULTS

A total of 5981 patients met the inclusion criteria of whom 9.2% (n=551) developed post-traumatic depression. The mean age of the cohort was 42 [standard deviation (SD) 18] years and 27.1% (n=1620) were females. The mean injury severity score was 9 (SD 9) with 18.4% (n=1100) of the patients assigned a score of at least 16. Six variables were identified as independent predictors for post-traumatic depression. Factors relating to the patient were female gender and age. Injury-specific variables were penetrating trauma and GCS score of≤8 on admission. Furthermore, intensive care admission and increasing hospital length of stay were predictors of depression.

CONCLUSION

Several risk factors associated with the development of post-traumatic depression were identified. A better targeted in-hospital screening and patient-centered follow up can be offered taking these risk factors into consideration.

Does early beta-blockade in isolated severe traumatic brain injury reduce the risk of post traumatic depression?

INTRODUCTION

Depressive symptoms occur in approximately half of trauma patients, negatively impacting on functional outcome and quality of life following severe head injury. Pontine noradrenaline has been shown to increase upon trauma and associated β-adrenergic receptor activation appears to consolidate memory formation of traumatic events. Blocking adrenergic activity reduces physiological stress responses during recall of traumatic memories and impairs memory, implying a potential therapeutic role of β-blockers. This study examines the effect of pre-admission β-blockade on post-traumatic depression.

METHODS

All adult trauma patients (≥18 years) with severe, isolated traumatic brain injury (intracranial Abbreviated Injury Scale score (AIS) ≥3 and extracranial AIS <3) were recruited from the trauma registry of an urban university hospital between 2007 and 2011. Exclusion criteria were in-hospital deaths and prescription of antidepressants up to one year prior to admission. Pre- and post-admission β-blocker and antidepressant therapy data was requested from the national drugs registry. Post-traumatic depression was defined as the prescription of antidepressants within one year of trauma. Patients with and without pre-admission β-blockers were matched 1:1 by age, gender, Glasgow Coma Scale, Injury Severity Score and head AIS. Analysis was carried out using McNemar's and Student's t-test for categorical and continuous data, respectively.

RESULTS

A total of 545 patients met the study criteria. Of these, 15% (n=80) were prescribed β-blockers. After propensity matching, 80 matched pairs were analyzed. 33% (n=26) of non β-blocked patients developed post-traumatic depression, compared to only 18% (n=14) in the β-blocked group (p=0.04). There were no significant differences in ICU (mean days: 5.8 (SD 10.5) vs. 5.6 (SD 7.2), p=0.85) or hospital length of stay (mean days: 21 (SD 21) vs. 21 (SD 20), p=0.94) between cohorts.

CONCLUSION

β-blockade appears to act prophylactically and significantly reduces the risk of post-traumatic depression in patients suffering from isolated severe traumatic brain injuries. Further prospective randomized studies are warranted to validate this finding.

The Buccinator Mucomuscular Flap: An In-Depth Analysis and Evaluation of Its Role in the Management of Velopharyngeal Dysfunction

Background

A significant proportion of patients with cleft palate experience persisting velopharyngeal dysfunction (VPD) after primary surgery. Pharyngoplasty is the most common procedure to correct inadequate velopharyngeal closure. Although it is often effective, it poses a risk for postoperative airway obstruction. The mucomuscular buccinator flap is a more recent alternative: In the largest case series to date, we outline its use and evaluate its effectiveness in managing persistent VPD.

Methods

Over 9 years, 103 buccinator flap procedures were performed by the Cambridge group to improve velar function. Clinical records were retrospectively assessed: 60 patients were analyzed by two expert speech and language therapists external to the group using the Cleft Audit Protocol for Speech—Augmented. In a subset of patients, the buccinator flap was interpolated between the limbs of a large mucosal Z-plasty. Consensus listening was undertaken, and interrater reliability was calculated for 24.17% of the cohort. The remaining samples were assessed by a single listener following calibrated consensus listening.

Results

There was a significant reduction in VPD ( P < .001). Preoperatively, 68.5% of patients demonstrated marked VPD, falling to 24.1% postoperatively. The buccinator procedure demonstrated significant improvement for three of four individual speech parameters: hypernasality, passive cleft speech characteristics, and audible nasal emission. Overall, 13.5% of patients required further corrective speech surgery.

Conclusions

The buccinator mucomuscular flap reliably and effectively improves velar function in the management of VPD and has low complication rates. We therefore recommend the use of the buccinator flap in primary surgical management of persisting VPD.

Digital rectal examination for initial assessment of the multi-injured patient: Can we depend on it?

BACKGROUND

Digital rectal examination (DRE) is part of the assessment of trauma patients as recommended by ATLS(®). The theory behind is to aid early diagnosis of potential lower intestinal, urethral and spinal cord injuries. Previous studies suggest that test characteristics of DRE are far from reliable. This study examines the correlation between DRE findings and diagnosis and whether DRE findings affect subsequent management.

MATERIALS AND METHODS

Patients with ICD-10 codes for spinal cord, urethral and lower intestinal injuries were identified from the trauma registry at an urban university hospital between 2007 and 2011. A retrospective review of electronic medical records was carried out to analyse DRE findings and subsequent management.

RESULTS

253 patients met the inclusion criteria with a mean age of 44 ± 20 years and mean ISS of 26 ± 16. 160 patients had detailed DRE documentation with abnormal findings in 48%. Sensitivity rate was 0.47. Correlational analysis between examination findings and diagnosis gave a kappa of 0.12. Subsequent management was not altered in any case due to DRE findings.

CONCLUSION

DRE in trauma settings has low sensitivity and does not change subsequent management. Excluding or postponing this examination should therefore be considered.

Increased left ventricular mass in obese adolescents*1

AIMS

An increase of left ventricular mass (LVM) has been reported in obese adolescents in previous studies using echocardiography. The aim of our study was to determine the extent of the increase in LVM and correlation to other risk factors using cardiac magnetic resonance imaging in obese and lean adolescents.

METHODS AND RESULTS

Nineteen obese and 20 lean adolescents were recruited. Following resting blood pressure measurements and blood sampling for insulin, triglycerides, and cholesterol levels, all subjects underwent cardiac magnetic resonance examination to assess LVM. LVM adjusted for body height was 16% greater in obese compared to lean adolescents (median 66 g/m, p = 0.0042). Obese subjects had higher resting systolic blood pressures than controls (median 115 vs. 110 mmHg, p = 0.0077) and higher fasting triglyceride and insulin levels. HDL-cholesterol levels were lower in the obese group compared with the lean group.

CONCLUSIONS

Obese adolescents had a higher LVM than age-matched lean subjects, which correlated mainly with body mass index and systolic blood pressure. These findings add to the established cardiovascular risk profile of obese adolescents.

[Classical swine fever]

The principles of aetiology, pathogenesis, diagnosis and immunology of classical swine fever as well as control measures are described. This review focuses on new diagnostic methods, immune reactions and possibilities for control of CSF in the context of the current eradication plans.

[Comparison of different BVD virus strains for their use in the differential diagnosis of classical swine fever--an attempt to standardize neutralization tests]

Six bovine virus diarrhoea (BVD) virus strains were tested in the neutralization test for their use in the differential diagnosis in classical swine fever (CSF) serology. The aim of the investigation was to find a suitable BVD virus strain guaranteeing a safe differentiation of CSF- and BVD virus induced antibodies using permanent cell cultures (PK-15, MDBK). For test purposes the neutralizing antibody titres of 73 defined test sera were titrated against the CSF virus strain Alfort/187 as well as the BVD virus strains Grub, Paplitz, NADL, 1138/69, Stendal, 10421/Han 94). Tests were repeated fivefold. The level of mean antibody titres, the differences in titre to the homologous pestivirus strain, the standard deviation and the variation coefficient served as test criteria. The BVD virus strains Grub and NADL yielded the best results. In view of harmonization and standardization the BVD virus strain NADL in connection with a standard protocol for neutralization tests is recommended for the differential diagnosis in CSF serology. Due to the adaptation of the permanent cell-lines PK-15 and MDBK to horse serum a further source of contamination with non cytopathogenic BVD viruses under routine conditions can be excluded.

[Quality management in the serodiagnosis of European swine fever: results of comparative tests]

In the course of inter-laboratory quality management comparative serological tests on classical swine fever (CSF) are conducted once per year. Results from tests carried out in 1994 and 1995 indicate that most regional diagnostic laboratories were able to classify the test sera correctly as CSF-positive, bovine viral diarrhea (BVD)-positive and negative, respectively. Difficulties were encountered in the differential diagnosis of CSF and BVD in neutralisation tests. There is a need to improve the standardization of CSF serology on the basis of a well established method in order to ensure reliability of test results and to enable comparison of results obtained from different laboratories.

Differentiation of classical swine fever virus (CSFV) strains using monoclonal antibodies against structural glycoproteins

Two panels of monoclonal antibodies (mAbs) against the classical swine fever virus (CSFV) envelope glycoproteins E2 (12 mAbs) and E0 (11 mAbs) were established and tested by immunoperoxidase binding assay against 135 pestivirus strains and isolates. Variability of the binding pattern was demonstrated for CSFV and also for bovine viral diarrhea virus (BVDV) strains and isolates. The panels of mAbs against E2 and E0 led to very different reactivity patterns. Particular mAbs against E2 reacted with (i) all CSFV isolates, (ii) only 4 out of 126 CSFV isolates, or (iii) about 90% of the tested CSFV isolates and 78% of ruminant pestivirus isolates. Anti CSFV E0 mAbs allowed the detection of a greater variability among the CSFV strains and isolates than the anti E2 mAbs. None of the 11 anti E0 mAbs recognized an epitope conserved for CSFV or showed crossreactivity with ruminant pestiviruses. The use of both panels of mAbs against two CSFV structural glycoproteins led to the discrimination of 21 antigenic types of CSFV strains and isolates. The described panels can be used to trace the origin of CSFV after outbreaks of the disease.

Inactivation of viruses in liquid manure

The stability of some viruses and methods of virus inactivation in liquid manure are reviewed. The authors discuss experimental data on the stability of foot and mouth disease virus, classical swine fever virus, Aujeszky's disease virus, African swine fever virus, swine influenza virus, porcine paramyxovirus, bovine virus diarrhoea virus and transmissible gastroenteritis of pigs virus. Recommendations and practical advice are given for the choice and application of chemical disinfectants for slurry.

Detection of foot-and-mouth disease virus in nasal swabs of asymptomatic cattle by RT-PCR within 24 hours

A method for extracting RNA from animal-derived materials that provides foot-and-mouth disease viral template suitable for Tth polymerase-dependent synthesis of cDNA and subsequent PCR is described. Viral genomes were detected in less than 24 h. Nasal swabs that can be easily and repeatedly collected, proved suitable for virus detection by PCR, even during the asymptomatic stages of infection.

Amino acid changes outside the G-H loop of capsid protein VP1 of type O foot-and-mouth disease virus confer resistance to neutralization by antipeptide G-H serum

Antiserum to a peptide corresponding to the 135-154 sequence of capsid protein VP1 of the foot-and-mouth disease virus O1 Kaufbeuren was raised in a pig. Although this serum contained neutralizing antibodies, the pig showed clinical symptoms after challenge. Virus isolated from this pig was identified as a mutant, with changes at positions 50, 198 and 211 of VP1 and at position 209 of VP2. This mutant, as well as a plaque isolate of it, differing from the challenge virus at positions 198 on VP1 (alanine being substituted for glutamic acid) and 209 on VP2 (histidine being substituted for tyrosine) resisted neutralization by the anti-peptide serum also in vitro. The same was observed with the O1 Kaufbeuren-related strain O1 Burgwedel, isolated from cattle in the field. It had substitutions only at positions 43 and 101 on VP1. The results show that neutralization epitopes flanking positions 145-147 on VP1 are modulated by other capsid protein parts. These parts seem to be important for neutralization escape in natural FMDV host species.

A second envelope glycoprotein mediates neutralization of a pestivirus, hog cholera virus

Several monoclonal antibodies (MAbs) raised against hog cholera virus (HCV) reacted with the HCV structural glycoprotein gp44/48 and neutralized the virus. The presence of HCV gp44/48 on the viral surface was directly demonstrated by immunogold electron microscopy. Eight anti-HCV gp44/48 MAbs were tested by immunoperoxidase assay against a panel of pestivirus strains. Each MAb showed a distinct pattern of reactivity with HCV strains. It is suggested that the MAbs are well suited for epidemiological investigations of HCV outbreaks.

Identification of foot-and-mouth disease virus replication in vaccinated cattle by antibodies to non-structural virus proteins

Antibodies raised in cattle against foot-and-mouth disease virus by vaccination or by experimental infection were distinguished. Vaccination elicited only antibodies to virus capsid proteins and the polymerase 3D. Virus replication in cattle elicited additional antibodies directed against the non-structural proteins 2B, 2C, 3AB1, and/or 3C irrespective of prior vaccination or whether the cattle exhibited symptoms of disease. Non-permissive mice inoculated with virus responded in the same way, indicating that antibodies raised due to the transient presence of antigen are safely recognized by the method applied which was radioimmunoprecipitation. All kinds of infections were thus detected and it was possible to differentiate between cattle exposed or not exposed to challenge in the field, and further between protected animals and possible virus carriers.

Effect of inhibitors of methylation on early and late interferon synthesis in bovine kidney cell cultures

In virus infected bovine kidney cell cultures mainly late interferon is produced starting at about 4 hr after infection. Poly rI:poly rC induced cells as well as interferon pretreated virus infected cells produce early interferon starting immediately after induction. In infected cells the proportion of early interferon increases with time of interferon pretreatment, while late interferon is decreasing. Production of late interferon is selectively inhibited by cycloleucine, an inhibitor of S-adenosylmethionine (SAM) biosynthesis, whereas early interferon synthesis is not affected by the drug. Likewise, late interferon production is reduced much stronger than early interferon production by a combination of adenosine, L-homocysteine thiolactone, and erythro-9[3-(2-hydroxynonyl)]-adenine (EHNA) inducing in cells an accumulation of S-adenosylhomocysteine which inhibits SAM mediated methylation reactions. Inhibition of late interferon synthesis by cycloleucine is time and dose dependent and partially reversible. Cycloheximide equally blocks both early and late interferon production. Inhibition of incorporation of methyl groups into cellular RNA by the methylation inhibitors used is demonstrated by labeling with [methyl-3H] methionine and 3H-uridine. The results indicate that the synthesis of functional mRNA for early and late interferon is differentially sensitive to inhibition of methylation. The data suggest that, if early and late interferon is coded by the same structural gene, two different pathways are available for the cell to synthesize one species of mRNA.

Multiplication and distribution of Aujeszky's disease (pseudorabies) virus in vaccinated and non-vaccinated pigs after intranasal infection

The primary sites of Aujeszky's disease virus (ADV) multiplication in intranasally (i.n.) infected pigs were found to be in the nasopharyngeal, tracheal and pulmonary regions. From the second day post infection (DPI) onward ADV invaded the central nervous system and other organs. The virus was isolated from the nasopharyngeal region for at least 2 weeks. In serum ADV was present with low levels from DPI 1 to DPI 7. In pigs vaccinated with an inactivated vaccine and then challenged the distribution of ADV was rather similar to that in non-vaccinated animals, in spite of the presence of neutralizing antibodies. The virus titres in the organs generally were lower than in non-vaccinated animals up to DPI 7. Thereafter, titre differences were no longer significant. Virus was isolated from the tonsils and the lungs for at least 2 weeks. Interferon production in vaccinated infected pigs was significantly lower than in non-vaccinated infected pigs. Though multiplication and dissemination of ADV occurred, vaccinated pigs did not show clinical symptoms of Aujeszky's disease. Traces of ADV were detected in a small percentage of white blood cells (WBC) of non-vaccinated infected pigs. ADV was isolated from the lymphocyte-enriched and polymorphnuclear leukocyte-enriched fractions, but not from the monocyte-enriched fractions, apparently on account of the small cell number. Multiplication of ADV was demonstrated in cultured WBC from some of the vaccinated and non-vaccinated infected animals.

Assay of bovine interferons in cultures of the porcine cell line IB-RS-2

An assay for bovine interferons has been developed using the porcine cell line IB-RS-2 and a bovine enterovirus, CBV-D, as challenge virus. The method is based on estimation of cytopathic effect measured by uptake of neutral red. Teh assay is simple, sensitive, and reproducible. A comparative test of different viruses in IB-RS-2 cells and secondary calf kidney cells revealed that the sensitivity of a virus to interferon can vary up to 1,000-fold in the two cell systems. Vesicular stomatitis virus was found to be rather insensitive to interferon in IB-RS-2 cells.

Inhibitors of foot-and-mouth disease virus. Temperature-dependence of the effect of guanidine on virus growth

In suspended secondary calf kidney cells infected with foot-and-mouth disease virus (FMDV) the temperature range for optimal virus growth is shifted down by 3 to 5 degrees C in the presence of 1--2 mM guanidine. For some virus strains this shift is so effective that at infraoptimal temperatures virus yield in guanidine-treated cells exceeds that of the corresponding control by more than one log10. On the contrary, at supraoptimal temperatures inhibition of virus growth by the drug is strongly enhanced. At a concentration of 1 to 2 mM guanidine virus yield reduction or enhancement is based on a decrease in increase, respectively, of the number of virus producing cells (infective centers; I.C.), while virus yield per I.C. is less affected. Besides this "thermomimetic" effect virus production is inhibited by guanidine depending on the concentration of this substance. A mutant of FMDV strain O1L, resistant to 4.2 guanidine, did not differ from the original virus in its antigenic behaviour in the passive immunohemolysis test.