Development of a core descriptor set for Crohn's anal fistula

AIM

Crohn's anal fistula (CAF) is a complex condition, with no agreement on which patient characteristics should be routinely reported in studies. The aim of this study was to develop a core descriptor set of key patient characteristics for reporting in all CAF research.

METHOD

Candidate descriptors were generated from published literature and stakeholder suggestions. Colorectal surgeons, gastroenterologists and specialist nurses in inflammatory bowel disease took part in three rounds of an international modified Delphi process using nine-point Likert scales to rank the importance of descriptors. Feedback was provided between rounds to allow refinement of the next ratings. Patterns in descriptor voting were assessed using principal component analysis (PCA). Resulting PCA groups were used to organize items in rounds two and three. Consensus descriptors were submitted to a patient panel for feedback. Items meeting predetermined thresholds were included in the final set and ratified at the consensus meeting.

RESULTS

One hundred and thirty three respondents from 22 countries completed round one, of whom 67.0% completed round three. Ninety seven descriptors were rated across three rounds in 11 PCA-based groups. Forty descriptors were shortlisted. The consensus meeting ratified a core descriptor set of 37 descriptors within six domains: fistula anatomy, current disease activity and phenotype, risk factors, medical interventions for CAF, surgical interventions for CAF, and patient symptoms and impact on quality of life.

CONCLUSION

The core descriptor set proposed for all future CAF research reflects characteristics important to gastroenterologists and surgeons. This might aid transparent reporting in future studies.

Management of Cylindrical Battery Ingestion

Presentation A female presented to the Emergency Department following ingestion of an unknown number of cylindrical batteries. Diagnosis Abdominal X-ray confirmed the presence of multiple batteries located throughout the abdomen. Treatment A trial of conservative management was pursued, and five AA batteries were successfully passed per rectum. Serial X-rays over three weeks revealed that the majority of batteries failed to pass. A decision was made to perform a laparotomy, and 46 cylindrical batteries were removed from the stomach through a small gastrotomy. Four batteries located in the colon were milked into the rectum and removed via the transanal route. Discussion Using daily clinical exams and weekly plain films of the abdomen, conservative management is possible if a small number of batteries are ingested and make it to the stomach. However, the potential of cylindrical batteries to result in acute surgical emergencies should not be underestimated.

Clinicopathological features and oncological outcomes of patients with young-onset rectal cancer

BACKGROUND

The incidence of rectal cancer among adults aged less than 50 years is rising. Survival data are limited and conflicting, and the oncological benefit of standard neoadjuvant and adjuvant therapies is unclear.

METHODS

Disease-specific outcomes of patients diagnosed with rectal cancer undergoing surgical resection with curative intent between 2006 and 2016 were analysed.

RESULTS

A total of 797 patients with rectal cancer were identified, of whom 685 had surgery with curative intent. Seventy patients were younger than 50 years and 615 were aged 50 years or more. Clinical stage did not differ between the two age groups. Patients aged less than 50 years were more likely to have microsatellite instability (9 versus 1·6 per cent; P = 0·003) and Lynch syndrome (7 versus 0 per cent; P < 0·001). Younger patients were also more likely to receive neoadjuvant chemoradiotherapy (67 versus 53·3 per cent; P = 0·003) and adjuvant chemotherapy (41 versus 24·2 per cent; P = 0·006). Five-year overall survival was better in those under 50 years old (80 versus 72 per cent; P = 0·013). The 5-year disease-free survival rate was 81 per cent in both age groups (P = 0·711). There were no significant differences in the development of locoregional recurrence or distant metastases.

CONCLUSION

Despite accessing more treatment, young patients have disease-specific outcomes comparable to those of their older counterparts.

Minimally invasive approaches to the management of anastomotic leakage following restorative rectal cancer resection

AIM

Management of anastomotic leakage (AL) following rectal resection has evolved with increasing use of less invasive techniques. The aim of this study was to review the management of AL following restorative rectal cancer resection in a tertiary referral centre.

METHOD

A retrospective review of a prospectively maintained database was performed. The primary outcome was successful management of AL. The secondary outcome was the impact of AL on oncological outcome.

RESULTS

Five hundred and two restorative rectal cancer resections were performed during the study period. The incidence of AL was 9.9% (n = 50). AL occurred more commonly following neoadjuvant chemoradiotherapy (n = 31/252, 12.3%) than in those who did not receive neoadjuvant chemoradiotherapy (n = 19/250, 7.6%; P = 0.107); however, this was not statistically significant. Successful minimally invasive drainage was achieved in 28 patients (56%, radiological n = 24, surgical n = 4). Trans-rectal drainage was the most common drainage method (n = 14). The median duration of drainage was longer in the neoadjuvant group (27 vs 18 days). Surgical intervention was required in 11 patients, with anastomotic takedown and end-colostomy formation was most commonly required. Successful management of AL with drainage (maintenance of the anastomosis without the need for further intervention) was achieved in 26 of the 28 patients. There were no significant differences in overall or disease-free survival when patients with AL were compared with patients without AL (69.4% vs 72.6%, P = 0.99 and 78.7% vs 71.3%, P = 0.45, respectively).

CONCLUSION

In selected patients, AL following restorative rectal resection can be effectively controlled using minimally invasive radiological or surgical drainage without the need for further intervention.

Prospective cohort study of appendicectomy for treatment of therapy-refractory ulcerative colitis

Introduction

Appendicectomy may reduce relapses and need for medication in patients with ulcerative colitis, but long-term prospective data are lacking. This study aimed to analyse the effect of appendicectomy in patients with refractory ulcerative colitis.

Methods

In this prospective multicentre cohort series, all consecutive patients with refractory ulcerative colitis referred for proctocolectomy between November 2012 and June 2015 were counselled to undergo laparoscopic appendicectomy instead. The primary endpoint was clinical response (reduction of at least 3 points in the partial Mayo score) at 12 months and long-term follow-up. Secondary endpoints included endoscopic remission (endoscopic Mayo score of 1 or less), failure (colectomy or start of experimental medication), and changes in Inflammatory Bowel Disease Questionnaire (IBDQ) (range 32–224), EQ-5D™ and EORTC-QLQ-C30-QL scores.

Results

A total of 28 patients (13 women; median age 40·5 years) underwent appendicectomy. The mean baseline IBDQ score was 127·0, the EQ-5D™ score was 0·65, and the EORTC-QLQ-C30-QL score was 41·1. At 12 months, 13 patients had a clinical response, five were in endoscopic remission, and nine required a colectomy (6 patients) or started new experimental medical therapy (3). IBDQ, EQ-5D™ and EORTC-QLQ-C30-QL scores improved to 167·1 (P &lt; 0·001), 0·80 (P = 0·003) and 61·0 (P &lt; 0·001) respectively. After a median of 3·7 (range 2·3–5·2) years, a further four patients required a colectomy (2) or new experimental medical therapy (2). Thirteen patients had a clinical response and seven were in endoscopic remission. The improvement in IBDQ, EQ-5D™ and the EORTC-QLQ-C30-QL scores remained stable over time.

Conclusion

Appendicectomy resulted in a clinical response in nearly half of patients with refractory ulcerative colitis and a substantial proportion were in endoscopic remission. Elective appendicectomy should be considered before proctocolectomy in patients with therapy-refractory ulcerative colitis.

Biomass burning and carbon monoxide patterns in Brazil during the extreme drought years of 2005, 2010, and 2015

In the 21st century, severe droughts associated with climate change will increase biomass burning (BB) in Brazil caused by the human activities. Recent droughts, especially in 2005, 2010, and 2015, caused strong socioeconomic and environmental impacts. The 2015 drought considered the most severe since 1901, surpassed the 2005 and 2010 events in respect to area and duration. Herein, based on satellite data, the 2005, 2010 and 2015 drought impacts on wildfire episodes and carbon monoxide (CO) variability during the dry and the dry-to-wet transition seasons were examined. The BB occurrences in the dry season were fewer during 2015 than during 2005 (-44%) and 2010 (-47%). Contrasting, the BB events in the dry-to-wet transition season, were higher during 2015 than during 2005 (+192%) and 2010 (+332%). The BB outbreaks were concentrated in the southern and southwestern Amazon during 2005, in the Cerrado region during 2010, and mainly in the central and northern Amazon during 2015, an area normally with few fires. The CO concentration showed positive variations (up to +30%) occurred in the southern Amazon and central Brazil during the 2005 and 2010 dry seasons, and north of 20 °S during the 2015-2016 dry-to-wet transition season. The BB outbreaks and the CO emissions showed a considerable spatiotemporal variability among the droughts of 2005, 2010, and 2016, first of them driven by local conditions in the tropical North Atlantic (TNA), characterized by warm than normal sea surface waters and the other two by the El Niño occurrences.

Effects of CDX2 on prognosis and chemotherapy responsiveness in mismatch repair-deficient colorectal cancer

Background

Caudal‐related homeobox transcription factor 2 (CDX2) is an intestine‐specific transcription factor implicated in tumour differentiation, proliferation, cell adhesion and migration. Negative CDX2 status (CDX2−) is associated with worse prognosis in colorectal cancer and may identify high‐risk stage II disease that benefits from adjuvant chemotherapy. This observational study investigated whether CDX2− is associated with prognosis or response to chemotherapy in the mismatch repair‐deficient (dMMR) phenotype of colorectal cancer.

Methods

Patients with resectable dMMR colorectal cancer were eligible for inclusion. The prognostic and predictive value of CDX2 expression on the presence of lymph node metastasis (LNM) and survival was investigated. CDX2 status was determined via immunohistochemistry using the Leica Bond™ CDX2 (clone EP25) ready‐to‐use primary antibody.

Results

Some 235 of 238 consecutive dMMR tumours were assessed for CDX2 status. CDX2− was observed in 15·7 per cent of colorectal cancer. Interobserver agreement was excellent (κ = 0·863; P < 0·001). CDX2− was significantly associated with female sex, increased size, advanced stage, worse conventional and poorly differentiated cluster (PDC) grade, mucinous morphology, perineural and lymphovascular invasion, and pN status (all P ≤ 0·038). CDX2− was not associated with LNM or survival in multivariable analysis. Independent predictors of LNM were PDC grade (odds ratio (OR) 4·12, 95 per cent c.i. 1·76 to 9·63; P = 0·001) and extramural venous invasion (OR 3·79, 1·62 to 8·85; P = 0·002). Budding (hazard ratio (HR) 2·79, 95 per cent c.i. 1·60 to 4·87; P < 0·001), pT status (HR 3·59, 1·29 to 10·01; P = 0·015) and adjuvant chemotherapy (HR 2·07, 1·15 to 3·74; P = 0·016) were independently associated with worse disease‐free survival.

Conclusion

CDX2− does not confer a worse prognosis in the dMMR phenotype of colorectal cancer. The MMR status of patients with colorectal cancer should be determined before assessing CDX2 status.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Microsatellite instability is associated with reduced disease specific survival in stage III colon cancer

BACKGROUND

Up to 15% of colorectal cancers exhibit microsatellite instability (MSI), where errors in replication go unchecked due to defects in the mismatch repair system. This study aimed to determine survival in a large single-centre series of 1250 consecutive colorectal cancers subjected to universal MSI testing.

METHODS

Clinical and pathological features of patients with colorectal cancer identified on prospectively maintained colorectal and pathology databases at St. Vincent's University Hospital from 2004 to May 2012 were examined. Mismatch repair (MMR) status was determined by immunohistochemistry. Kaplan-Meier curves, the log-rank test and Cox regression were used to associate survival with clinical and pathological characteristics.

RESULTS

Of the 1250 colorectal cancers in the study period, 11% exhibited MSI (n = 138). Patients with MSI tumours had significantly lower rates of lymph node and distant metastases (MSI N+ rate: 24.8% compared with MSS N+ rate: 46.2%, p < 0.001). For Stage I and II disease MSI was associated with improved disease free survival (DSS) compared with MSS colon cancer. However, patients with Stage III MSI colon cancers had a worse DSS than those with MSS tumours. Stage III MSI tumours exhibited higher rates of lymphovascular invasion and perineural invasion than Stage I/II MSI tumours.

CONCLUSION

MSI is associated with a reduced risk of nodal and distant metastases, with an improved DSS in Stage I/II colon cancer. However, when MSI tumours progress to Stage III these patients had worse outcomes and pathological features. New strategies for this cohort of patients may be required to improve outcomes.

A radiological and pathological assessment of ileocolic pedicle length as a predictor of lymph node retrieval following right hemicolectomy for caecal cancer

BACKGROUND

In colon cancer, the number of harvested lymph nodes is critical for pathological staging. It has been proposed that the more central the mesenteric vascular ligation, the greater the nodal yield. The aim of the current study was to determine the association of radiological and pathological ileocolic pedicle length on nodal harvest following right hemicolectomy for caecal cancer.

METHODS

A series of 50 patients undergoing right hemicolectomy for adenocarcinoma underwent specimen evaluation. Preoperative computed tomography images were reconstructed and analysed to determine the direct (vessel origin to caecum) ileocolic pedicle length.

RESULTS

The median pathological distance from the tumour to the high vascular tie was 80 mm, and median nodal yield was 16.5 nodes. Radiological pedicle length did not correlate with the pathological distance from the tumour to the high vascular tie or nodal yield; however, the pathological pedicle length did correlate with the total nodal yield (r (2): 0.343, p = 0.015). The median pathologically determined length of colon resected (r (2): 0.153, p = 0.289), ileum resected (r (2): 0.087, p = 0.568) and total specimen length resected (r (2): 0.182, p = 0.205) did not correlate with the total nodal yield. An ileal specimen length ≤25 mm [hazard ratio (HR) 14.8, 95 % confidence interval (CI) 1.1-194.5, p = 0.040] and a well-differentiated tumour (HR 10.5, 95 % CI 1.1-95.9, p = 0.037) increased the likelihood of retrieving <12 lymph nodes.

CONCLUSIONS

Based on these data, pathologic pedicle length is a determining factor in lymph node retrieval. Preoperative radiological calculation of pedicle length does not help predict the number of lymph nodes retrieved.

Segmental vs extended colectomy in the management of hereditary nonpolyposis colorectal cancer: a systematic review and meta-analysis

AIM

The optimal surgical approach to the management of colorectal cancer in the setting of hereditary nonpolyposis colorectal cancer (HNPCC) is contentious. While some advocate total colectomy, others perform segmental resection followed by regular endoscopic surveillance. This systematic review evaluates the evidence for segmental colectomy (SC) and total (extended) colectomy (TC) in the management of HNPCC.

METHOD

Two major databases (PubMed and Cochrane) were searched using predefined terms. All original articles, published in English, comparing the oncological outcomes of SC and TC in HNPCC patients from January 1950 to July 2013 were included.

RESULTS

Eighty-four studies were identified. After applying exclusion criteria, six studies involving 948 patients were included (mean age 47.4 years, 51.8% male). SC was more commonly performed than TC (n = 780; 82.3%). Mean follow-up was 106.5 months. Metachronous high-risk adenomas were detected more often after SC, although the difference was not statistically significant (23.4% vs 9.6%; OR 2.258, P = 0.057). Metachronous cancers occurred more frequently after SC than after TC (23.5% vs 6.8%; OR 3.679, P < 0.005). However, there was no difference in overall survival (90.7% vs 89.8% for SC and TC, respectively; P = 0.085). Only one study reported operative mortality (0% in each group), there was no report of operative morbidity or functional outcome.

CONCLUSION

The optimal surgical approach in the management of HNPCC remains unclear. More adenomas and cancers occur after SC than after TC but there certainly is no evidence to suggest that more radical surgery leads to improved survival.

Hepatitis B reactivation and rituximab: a new boxed warning and considerations for solid organ transplantation

Use of rituximab, a chimeric monoclonal antibody directed at the CD20 antigen, continues to increase in solid organ transplantation (SOT) for several off-label uses. In September 2013, the United States Food and Drug Administration (FDA) issued a Drug Safety Communication to oncology, rheumatology and pharmacy communities outlining a new Boxed Warning for rituximab. Citing 109 cases of fatal hepatitis B virus (HBV) reactivation in persons receiving rituximab therapy with previous or chronic HBV infection documented in their Adverse Event Reporting System (AERS), the FDA recommends screening for HBV serologies in all patients planned to receive rituximab and antiviral prophylaxis in any patient with a positive history of HBV infection. There is a lack of data pertaining to this topic in the SOT population despite an increase in off-label indications. Previous reports suggest patients receiving rituximab, on average, were administered six doses prior to HBV reactivation. Recommendations on prophylaxis, treatment and re-challenging patients with therapy after resolution of reactivation remain unclear. Based on data from the FDA AERS and multiple analyses in oncology, SOT providers utilizing rituximab should adhere to the FDA warnings and recommendations regarding HBV reactivation until further data are available in the SOT population.

Clostridium difficile enteritis: a new role for an old foe

BACKGROUND

Small bowel involvement of Clostridium difficile is increasingly encountered. Data on many management aspects are lacking.

AIM

To synthesis existing reports and assess the frequency, pathophysiology, outcomes, risk factors, diagnosis and management of C. difficle enteritis.

METHODS

A systematic review of the literature was conducted to evaluate evidence regarding frequency, pathophysiology, risk factors, optimal diagnosis, management and outcomes for C. difficle enteritis. Three major databases (PubMed, MEDLINE and the Cochrane Library) were searched. The review included original articles reporting C. difficle enteritis from January 1950 to December 2012.

RESULTS

C. difficle enteritis is rare but increasingly encountered. Presentation is variable and distinct predisposing factors include emergency surgery, white race and increased age. Diagnosis generally involves a sensitive but often non specific screening test for C. difficile antigens. Oral metronidazole represents first line therapy and surgery may be required for complications. Outcomes are inconsistent but may be improving.

CONCLUSIONS

A high index of clinical suspicion, early diagnosis and treatment are vital. Further prospective studies are needed to determine the significance of asymptomatic small bowel C. difficile infections.

Omental pedicle flaps following proctectomy: a systematic review

AIM

Abdominoperineal excision (APR) for cancer carries significant morbidity of the perineal wound. An omental pedicle graft has been used to fill the pelvis and limit attendant complications after radical extirpation of the anorectum. A review of the literature was conducted to determine whether omentoplasty following APR reduces perineal wound complications.

METHOD

Three major databases (PubMed, MEDLINE and the Cochrane Library) were searched. The review included original articles reporting outcomes after APR and omentoplasty from January 1950 to July 2012.

RESULTS

Fourteen studies involving 891 patients (mean age 61 years, 59.8% men) were included. Median follow-up was 13.5 months. A variety of omentoplasty techniques added a median of 20 min to the operating time. The mean rate of primary wound healing was 66.8%, time to wound healing 24 days and weighted mean wound infection rate 14.4% with omentoplasty compared with 50.1%, 79 days and 18.5% in patients having no omentoplasty.

CONCLUSION

Omental mobilization, transfer and buttressing of primary perineal repair following proctectomy reduces perineal wound morbidity with minimal additional operating time or flap-associated morbidity.

Risk factors associated with Clostridium difficile infection after kidney and pancreas transplantation

BACKGROUND

Clostridium difficile infection (CDI) is a common cause of nosocomial antibiotic-associated diarrhea with an increased incidence reported in solid organ transplant recipients. We sought to determine if kidney and/or pancreas transplant recipients possess unique risk factors for CDI.

METHODS

Between January 2009 and February 2011, 942 kidney and 56 pancreas transplants were performed at the 2 centers. Of these, 28 recipients (kidney, n = 24; pancreas, n = 4) developed CDI. Cases were matched to controls (n = 56) in a 1:2 ratio.

RESULTS

Those with CDI were mostly male patients (82% vs. 48%, P = 0.003), deceased-donor organ recipients (86% vs. 64%, P = 0.045), more likely to have leukopenia (18% vs. 4%, P = 0.038), and had undergone a gastrointestinal procedure within 3 months preceding CDI diagnosis (18% vs. 4%, P = 0.038). Cases had higher cumulative and restricted antimicrobial exposure in days (37 ± 79 vs. 8 ± 12, P = 0.009 and 27 ± 69 vs. 7 ± 10, P = 0.032). Cephalosporin use was more common among cases (43% vs. 16%, P = 0.008).

CONCLUSION

Careful antimicrobial selection and assurance of optimal treatment duration in the kidney and pancreas transplant population is prudent. Clinicians should have a heightened awareness of CDI risk particularly during periods of leukopenia and in the setting of gastrointestinal procedures.

Evaluating the impact of pre-transplant desensitization utilizing a plasmapheresis and low-dose intravenous immunoglobulin protocol on BK viremia in renal transplant recipients

BACKGROUND

A correlation exists between polyomavirus BK (BKV) viremia in renal transplant recipients (RTR) and the degree of immunosuppression. However, the impact of pre-transplant desensitization on the incidence of BKV viremia is unknown.

METHODS

This retrospective study evaluated living-donor RTR between January 2004 and December 2008 receiving routine BKV viral load monitoring. Patients were divided into those who underwent pre-transplant desensitization (n = 20) and those who did not (n = 71). The primary endpoint was the incidence of BKV viremia at 1 year post transplant.

RESULTS

All demographic data were similar, except for more female patients (65% vs. 36.6%; P = 0.0392) in the desensitized group. More desensitized patients had a previous transplant (75% vs. 12.7%; P < 0.0001) and were more likely to be induced with basiliximab (75% vs. 35.2%; P = 0.0021). Following transplantation, antibody-mediated rejection (AMR) rates were highest in the desensitized group (55% vs. 1.4%; P < 0.0001). The incidence of BKV viremia at 1 year post transplant was significantly higher in desensitized patients (45% vs. 19.7%; P = 0.0385). Desensitization was also associated with a higher prevalence of BKV viremia at any time post transplant (50% vs. 22.5%; P = 0.0245), polyomavirus-associated nephropathy (20% vs. 2.8%; P = 0.0198) and BKV-related allograft loss (10% vs. 0%; P = 0.0464). Also of note, in a subgroup analysis of only our desensitized patients, it did not appear that development of AMR significantly impacted the incidence of BKV viremia in these individuals.

CONCLUSIONS

This analysis reveals that pre-transplant desensitization significantly increases the risk for BKV viremia and nephropathy.

Systematic review and meta-analysis of outcomes following pathological complete response to neoadjuvant chemoradiotherapy for rectal cancer

BACKGROUND

Following neoadjuvant chemoradiotherapy (CRT) and interval proctectomy, 15-20 per cent of patients are found to have a pathological complete response (pCR) to combined multimodal therapy, but controversy persists about whether this yields a survival benefit. This systematic review evaluated current evidence regarding long-term oncological outcomes in patients found to have a pCR to neoadjuvant CRT.

METHODS

Three major databases (PubMed, MEDLINE and the Cochrane Library) were searched. The systematic review included all original articles reporting long-term outcomes in patients with rectal cancer who had a pCR to neoadjuvant CRT, published in English, from January 1950 to March 2011.

RESULTS

A total of 724 studies were identified for screening. After applying inclusion and exclusion criteria, 16 studies involving 3363 patients (1263 with pCR and 2100 without) were included (mean age 60 years, 65·0 per cent men). Some 73·4 per cent had a sphincter-saving procedure. Mean follow-up was 55·5 (range 40-87) months. For patients with a pCR, the weighted mean local recurrence rate was 0·7 (range 0-2·6) per cent. Distant failure was observed in 8·7 per cent. Five-year overall and disease-free survival rates were 90·2 and 87·0 per cent respectively. Compared with non-responders, a pCR was associated with fewer local recurrences (odds ratio (OR) 0·25; P = 0·002) and less frequent distant failure (OR 0·23; P < 0·001), with a greater likelihood of being alive (OR 3·28; P = 0·001) and disease-free (OR 4·33, P < 0·001) at 5 years.

CONCLUSION

A pCR following neoadjuvant CRT is associated with excellent long-term survival, with low rates of local recurrence and distant failure.

Systematic review of outcomes after intersphincteric resection for low rectal cancer

BACKGROUND

For a select group of patients proctectomy with intersphincteric resection (ISR) for low rectal cancer may be a viable alternative to abdominoperineal resection, with good oncological outcomes while preserving sphincter function. The purpose of this systematic review was to evaluate the current evidence regarding oncological outcomes, morbidity and mortality, and functional outcomes after ISR for low rectal cancer.

METHODS

A systematic review of the literature was undertaken to evaluate evidence regarding oncological outcomes, morbidity and mortality after ISR for low rectal cancer. Three major databases (PubMed, MEDLINE and the Cochrane Library) were searched. The review included all original articles reporting outcomes after ISR, published in English, from January 1950 to March 2011.

RESULTS

Eighty-four studies were identified. After applying inclusion and exclusion criteria, 14 studies involving 1289 patients were included (mean age 59.5 years, 67.0 per cent men). R0 resection was achieved by ISR in 97.0 per cent. The operative mortality rate was 0.8 per cent and the cumulative morbidity rate 25.8 per cent. Median follow-up was 56 (range 1-227) months. The mean local recurrence rate was 6.7 (range 0-23) per cent. Mean 5-year overall and disease-free survival rates were 86.3 and 78.6 per cent respectively. Functional outcome was reported in eight studies; among these, the mean number of bowel motions in a 24-h period was 2.7.

CONCLUSION

Oncological outcomes after ISR for low rectal cancer are acceptable, with diverse, often imperfect functional results. These data will aid the clinician when counselling patients considering an ISR for management of low rectal cancer.

Mesenteric venous thrombosis secondary to an unsuspected JAK2 V617F-positive myeloproliferative disorder

BACKGROUND

Mesenteric venous thrombosis (MVT) is a rare but potentially fatal cause of mesenteric ischaemia. It presents insidiously and often diagnosis is made at emergency surgery. In half of the cases MVT develops without a causative factor, while in cases in which a pro-thrombotic state is found to exist MVT may be the first clinically detected consequence of that state. The myeloproliferative disorders (MPD) are known to contribute to the development of pro-thrombotic states. Recently, the JAK2 V617F mutation has been associated with the MPDs.

CONCLUSION

We describe a case of MVT occurring secondary to an unsuspected MPD, in which the patient was subsequently found to carry this mutation. We highlight the necessity to screen for this mutation in cases of intra-abdominal thromboses so that appropriate systemic anticoagulation may be instituted, and the patient may be followed so as to detect the development of an overt MPD.

Isolated pancreatic metastases from a bronchogenic small cell carcinoma

We describe the case of a 60 year old female smoker who presented with a three month history of weight loss (14 Kg), generalized abdominal discomfort and malaise. Chest radiography demonstrated a mass projected inferior to the hilum of the right lung. Computed Tomography of thorax confirmed a lobulated lesion in the right infrahilar region and subsequent staging abdominal CT demonstrated a low density lesion in the neck of the pancreas. Percutaneous Ultrasound guided pancreatic biopsy was performed, histology of which demonstrated pancreatic tissue containing a highly necrotic small cell undifferentiated carcinoma consistent with metastatic small cell carcinoma of the bronchus.

Bouveret's syndrome--a rare presentation of gallstone ileus

We present the case of an elderly Irish male with Bouveret's syndrome--a very unusual cause of gallstone ileus, where a large gallstone occludes the gastric outlet or duodenum causing obstruction. Management of this condition is often controversial. We discuss the various medical, radiological and surgical therapies available for treatment of this rare entity. Bouveret's Syndrome--A Rare Presentation of Gallstone Ileus

Mass Spectral Evidence That Small Changes in Composition Caused by Oxidative Aging Processes Alter Aerosol CCN Properties

Oxidative processing (i.e., "aging") of organic aerosol particles in the troposphere affects their cloud condensation nuclei (CCN) activity, yet the chemical mechanisms remain poorly understood. In this study, oleic acid aerosol particles were reacted with ozone while particle chemical composition and CCN activity were simultaneously monitored. The CCN activated fraction at 0.66 +/- 0.06% supersaturation was zero for 200 nm mobility diameter particles exposed to 565 to 8320 ppmv O3 for less than 30 s. For greater exposure times, however, the particles became CCN active. The corresponding chemical change shown in the particle mass spectra was the oxidation of aldehyde groups to form carboxylic acid groups. Specifically, 9-oxononanoic acid was oxidized to azelaic acid, although the azelaic acid remained a minor component, comprising 3-5% of the mass in the CCN-inactive particles compared to 4-6% in the CCN-active particles. Similarly, the aldehyde groups of alpha-acyloxyalkylhydroperoxide (AAHP) products were also oxidized to carboxylic acid groups. On a mass basis, this conversion was at least as important as the increased azelaic acid yield. Analysis of our results with Köhler theory suggests that an increase in the water-soluble material brought about by the aldehyde-to-carboxylic acid conversion is an insufficient explanation for the increased CCN activity. An increased concentration of surface-active species, which decreases the surface tension of the aqueous droplet during activation, is an interpretation consistent with the chemical composition observations and Köhler theory. These results suggest that small changes in particle chemical composition caused by oxidation could increase the CCN activity of tropospheric aerosol particles during their atmospheric residence time.

Ozonolysis of Mixed Oleic-Acid/Stearic-Acid Particles: Reaction Kinetics and Chemical Morphology

The ozonolysis of mixed oleic-acid/stearic-acid (OL/SA) aerosol particles from 0/100 to 100/0 wt % composition is studied. The magnitude of the divergence of the particle beam inside an aerosol mass spectrometer shows that, in the concentration range 100/0 to 60/40, the mixed OL/SA particles are liquid prior to reaction. Upon ozonolysis, particles having compositions of 75/25 and 60/40 change shape, indicating that they have solidified during reaction. Transmission electron micrographs show that SA(s) forms needles. For particles having compositions of 75/25, 60/40, and greater SA content, the reaction kinetics exhibit an initial fast decay of OL for low O(3) exposure with no further loss of OL at higher O(3) exposures. For compositions from 50/50 to 10/90, the residual OL concentration remains at 28 +/- 2% of its initial value. The initial reactive uptake coefficient for O(3), as determined by OL loss, decreases linearly from 1.25 (+/-0.2) x 10(-3) to 0.60 (+/-0.15) x 10(-3) for composition changes of 100/0 to 60/40. At 50/50 composition, the uptake coefficient drops abruptly to 0.15 (+/-0.1) x 10(-3), and there are no further changes with increased SA content. These observations can be explained with a combination of three postulates: (1) Unreacted mixed particles remain as supersaturated liquids up to 60/40 composition, and the OL in this form rapidly reacts with O(3). (2) SA, as it solidifies, locks into its crystal structure a significant amount of OL, and this OL is completely inaccessible to O(3). (3) Accompanying crystallization, some stearic acid molecules connect as a filamentous network to form a semipermeable gel containing liquid OL but with a reduced uptake coefficient because of the decrease in molecular diffusivity in the gel. An individual particle of 50/50 to 90/10 is hypothesized as a combination of SA crystals having OL impurities (postulate 2) that are partially enveloped by an SA/OL gel (postulate 3) to explain (a) the abrupt drop in the uptake coefficient from 60/40 to 50/50 and (b) the residual OL content even after high ozone exposure. The results of this study, pointing out the important effects of particle phase, composition, and morphology on chemical reactivity, contribute to an improved understanding of the aging processes of atmospheric aerosol particles.

Aberrant methylation of the Human Hedgehog interacting protein (HHIP) gene in pancreatic neoplasms

Hedgehog pathway overactivity has been implicated in the development of a variety of human cancers. The Human Hedgehog interacting protein (HHIP), a negative regulator of hedgehog signaling, has been shown to be underexpressed in pancreatic cancers. In this study we determined if the HHIP gene is a target for genetic and epigenetic alterations. While no mutations of HHIP were identified, we found complete methylation of the HHIP promoter CpG island in three pancreatic cancer cell lines, and partial hypermethylation in 13/17 (80%) pancreatic cancer cell lines, 35/75 (46%) primary pancreatic cancers and 14/18 (78%) pancreatic cancer xenografts, but no methylation in 13 normal pancreata. In pancreatic cancer cell lines, complete methylation was associated with absent or reduced HHIP expression by real-time RT-PCR. HHIP expression could be restored in methylated cell lines using epigenetic modifier drugs. Restoring the expression of HHIP in pancreatic cancer cells by 5-aza-2'-deoxycytidine led to a decrease in Gli reporter activity, consistent with downregulation of Hedgehog signaling. These results indicate in some pancreatic adenocarcinomas that HHIP is epigenetically inactivated by promoter methylation, and its silencing could contribute to the increased Hedgehog signaling observed in pancreatic neoplasms.

Paraesophageal lymph node metastasis from prostatic adenocarcinoma in a patient with esophageal squamous carcinoma

SUMMARY. Esophageal squamous carcinomas induce regional immune suppression in the domain of the tumor while the global immune system remains intact. We report a patient with a squamous esophageal carcinoma, who was discovered at esophagectomy to have paraesophageal lymph node metastases from a prostatic adenocarcinoma. No other sites of metastatic disease were identified. This supports the concept that regional immune suppression by esophageal squamous cancers facilitates growth of metastases in the local lymph nodes.

Structure-activity relationships of mineral dusts as heterogeneous nuclei for ammonium sulfate crystallization from supersaturated aqueous solutions

Mineral inclusions, present in aqueous atmospheric salt droplets, regulate crystallization when relative humidity decreases by providing a surface for heterogeneous nucleation and thus reducing the critical supersaturation. Although laboratory studies have quantified these processes to some extent, the diverse atmospheric mineralogy presents more chemical systems than practically feasible for direct study. Structure--activity relationships are necessary. To that end, in the present work the interactions of ammonium sulfate with corundum, hematite, mullite, rutile, anatase, and baddeleyite were studied by diffuse reflectance fourier transform infrared spectroscopy (DRIFTS) and by epitaxial modeling. The spectroscopic results show that shifts in sulfate peak positions due to chemisorption are not a correlative indicator of the efficacy of heterogeneous nucleation. In contrast, epitaxial modeling results of unreconstructed surfaces explain the sequence of critical supersaturations for constant particle size. If validated by further work, this computer modeling method would provide an important structure--activity tool for the estimation of heterogeneous nucleation properties of the atmospheric mineralogy.

Evidence for conformational dynamics and molecular aggregation in cytochrome P450 102 (BM-3)

The native molecular weight of affinity-purified cytochrome P450 102 from barbiturate-induced Bacillus megaterium has been studied by sedimentation methods and HPLC size-exclusion chromatography. Sedimentation velocity experiments yielded an s020,w = 9.244 S for the holocytochrome, but the diffusion coefficient was unexpectedly large and varied widely with centrifugal field, ionic strength, and protein concentration. Addition of 50 mM DL-dithiothreitol (DTT) caused a small decrease in the value of s020,w, but D20 still did not behave as expected. The sedimentation coefficients were consistent with a molecular weight of about 200,000, and the diffusion coefficients indicated molecular aggregation. Sedimentation equilibrium analyses suggested that the native enzyme was a mixture of monomer, dimer, trimer, and tetramer. However, after incubation of P450 102 with DTT, sedimentation equilibrium demonstrated that the enzyme was dimeric (molecular weight 236,000). HPLC size-exclusion chromatography of the cytochrome showed the presence of four peaks, which corresponded to 1.45-mer, 2.06-mer, 3.02-mer, and a higher molecular weight fraction; aggregated forms accounted for about 52% of the P450 102. Incubation of the enzyme with DTT caused a shift toward the 1.45-mer, but dimer, trimer, and the high molecular weight peak still persisted; the shift was not attributable to disulfide bond reduction. The 1.45-mer was determined to be a monomeric species of significantly asymmetric geometry. Together, the results indicated that cytochrome P450 exists with monomer, dimer, trimer, etc. in equilibrium, contrary to the expectation that this soluble P450 would be monomeric.(ABSTRACT TRUNCATED AT 250 WORDS)

Membrane topology of liver microsomal cytochrome P450 2B4 determined via monoclonal antibodies directed to the halt-transfer signal

The membrane topology of cytochrome P450 2B4 from the endoplasmic reticulum has been studied with highly-purified liver microsomes in a site-directed immunochemical approach. Microsomes were prepared from phenobarbital-induced rabbits, and the resulting microsomal fraction was washed 6 additional times with 0.1 M pyrophosphate buffer to effect removal of significant quantities of adventitiously-bound protein. Monoclonal antibodies were prepared against residues 18-29 of P450 2B4 (Leu18-Leu-Phe-Arg-Gly-His-Pro-Lys-Ala-His-Gly-Arg29), essentially corresponding to the halt-transfer signal. This region was chosen due to its mutually-exclusive location in the two alternative membrane topology models currently tenable [Black, S.D. (1992) FASEB J.6, 680-685]. Model "A" contains a single transmembrane anchor peptide with the amino terminus projecting into the lumen of the endoplasmic reticulum, while model "B" exhibits a hairpin loop of the first approximately 46 residues inserted into the membrane with the amino terminus located on the cytosolic side of the lipid bilayer; the halt-transfer signal peptide would be located at the cytosolic surface of the membrane in model "A" or as a loop on the lumenal side of the membrane in model "B". Nine antibodies, denoted as MmAbA, MmAbC, MmAbD, MmAbF, MmAbH, MmAbI, MmAbK, MmAbL, and MmAbP, were produced, and all were identified as IgM/kappa subtypes. Western blotting demonstrated that the antibodies could readily recognize P450 2B4 in microsomes. ELISA assays showed that all of the antibodies exhibited strong binding to intact microsomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Detergent effects in rabbit liver microsomal UDP-glucuronosyltransferase studied by means of a continuous spectrophotometric assay with p-nitrophenol

UDP-glucuronosyltransferase (UDPGT) has been studied with a continuous spectrophotometric assay employing UDP-glucuronic acid and p-nitrophenol as substrates. Activity is linearly dependent on the microsomal protein concentration. Male rabbit liver phenobarbital-induced microsomes exhibited a rate of 7.10 microM p-nitrophenol conjugated per minute at 37 degrees C. Addition of small amounts of Tergitol NP-10 caused an approximately 4-fold increase in conjugation activity; maximal activation was observed at 0.01% (v/v) detergent. However, inclusion of additional detergent caused significant inhibition of activity, such that 0.5% Tergitol caused the rate to fall 2.5-fold below the activity observed in the absence of detergent. Membrane solubilization was studied by light scattering. At maximal stimulation of p-nitrophenol UDPGT activity, the membrane was solubilized only approximately 17%. At the point of 50% solubilization, activity was still 91% of maximum. Complete membrane solubilization was achieved at approximately 0.2% Tergitol, and transferase activity had fallen slightly below the rate observed in the absence of detergent. Possible explanations for the unusual detergent-dependence of microsomal p-nitrophenol UDPGT activity are discussed.

Comparison of resuscitation of sheep and dogs after bupivacaine-induced cardiovascular collapse

This study evaluated interspecies sensitivity and ability to resuscitate pentobarbital anesthetized sheep and dogs after cardiovascular toxic doses of bupivacaine. Every minute, 3 mg/kg of bupivacaine was injected into the right atrium over the course of 10 sec until cardiovascular collapse occurred. While the bupivacaine was given, the animals were made apneic for 90 sec and then ventilated with 100% oxygen. After the bupivacaine administration, cardiovascular collapse occurred in the form of electromechanical dissociation progressing to asystole in dogs, whereas in sheep the predominant rhythm was ventricular fibrillation leading to asystole. Resuscitation was performed using open chest heart massage, bretylium for treatment of ventricular tachycardia and fibrillation, and epinephrine with atropine for treatment of electromechanical dissociation or asystole. The initial dose of bupivacaine used to cause cardiovascular collapse was 3.5 +/- 1.2 mg/kg in sheep and 24.6 +/- 8.5 mg/kg in dogs (P less than 0.01). All sheep and dogs were resuscitated from the first cardiovascular collapse. The resuscitation time was 2.1 +/- 1.0 min in dogs and 36.9 +/- 15.4 min in sheep (P less than 0.01). All dogs could be resuscitated after two additional cardiovascular collapses induced by bupivacaine, but no sheep could be resuscitated after a second cardiovascular collapse. Concentrations of bupivacaine in cardiac tissue and serum levels of bupivacaine after the last resuscitation attempt were significantly greater in the dogs than in the sheep. We conclude that sheep are more sensitive to bupivacaine than dogs, but that even sheep can be resuscitated after cardiovascular collapse produced by bupivacaine.

Resuscitation from bupivacaine-induced cardiovascular toxicity during partial inferior vena cava occlusion

The hemodynamic effects and ability to resuscitate animals experiencing bupivacaine cardiovascular toxicity after partial inferior vena cava occlusion were investigated in anesthetized dogs (n = 12). Partial occlusion of the inferior vena cava resulted in a 12% decrease in mean arterial pressure, a 62% decrease in cardiac output, a 66% decrease in stroke volume, and a 135% increase in systemic vascular resistance. Bupivacaine, 20 mg/kg intravenously, resulted in cardiovascular collapse in all animals. The resuscitation time for animals without partial caval occlusion was 2.1 +/- 0.5 min, whereas that for animals with partial caval occlusion was 22.2 +/- 6.9 min (P less than 0.05). Significantly increased amounts of epinephrine and NaHCO3 were required to resuscitate the animals with caval occlusion. We conclude that partial inferior vena cava occlusion can significantly alter the ability to resuscitate animals experiencing bupivacaine cardiovascular toxicity.

Bupivacaine cardiovascular toxicity: comparison of treatment with bretylium and lidocaine

Using anesthetized dogs, this study compared treatment with lidocaine or bretylium for bupivacaine-induced cardiovascular toxicity. Pentobarbital-anesthetized and -ventilated dogs (n = 10) were given a bolus dose of bupivacaine, 4 mg/kg, and a constant infusion of 0.2 mg X kg-1 X min-1 to produce steady-state serum levels of 7.1 +/- 1.8 microgram/ml of bupivacaine. Using burst ventricular pacing, the ventricular tachycardia threshold was determined, along with hemodynamic and electrophysiologic parameters. The animals were then treated with bretylium, 20 mg/kg (n = 5), or lidocaine, 2 mg/kg, followed by a continuous infusion of lidocaine, 0.1 mg X kg-1 X min-1 (n = 5). Bupivacaine-induced alterations in cardiac output, stroke volume, heart rate, and systemic vascular resistance were corrected by bretylium but not lidocaine. Bupivacaine caused a significant lowering of the ventricular tachycardia threshold, which was consistently raised by bretylium, while lidocaine was either ineffective or caused a further lowering of the threshold. Bupivacaine caused a significant increase in the Q-TU interval and resulted in an undulating polymorphic ventricular tachycardia, similar to that seen in Torsades de Pointes.

Successful cardiovascular resuscitation after massive intravenous bupivacaine overdosage in anesthetized dogs

We investigated whether anesthetized dogs (n = 6) could be resuscitated from massive cardiovascular toxic intravenous bupivacaine overdoses. Five mg/kg of bupivacaine was given into the right atrium over 10 sec every minute until cardiac collapse occurred. At the same time the bupivacaine was given, the animals were made apneic for 90 sec (to mimic the clinical situation in which seizures often render patients apneic) and then ventilated with 100% oxygen. After bupivacaine administration, cardiovascular collapse occurred in the form of ventricular tachycardia, or more commonly, electromechanical dissociation. Resuscitation was performed using open-chest heart massage, bretylium for ventricular tachycardia, and epinephrine with atropine for electromechanical dissociation and bradycardia. After successful resuscitation, each animal was again given bupivacaine as above until cardiovascular collapse occurred and resuscitation was performed again. Each dog underwent three arrests and resuscitations. The total cumulative bupivacaine dose was 64.1 +/- 26.8 mg/kg. We conclude that anesthetized dogs receiving massive cardiovascular toxic doses of bupivacaine can be resuscitated easily and consistently with appropriate therapy.