A molecular atlas of adult C. elegans motor neurons reveals ancient diversity delineated by conserved transcription factor codes

Motor neurons (MNs) constitute an ancient cell type targeted by multiple adult-onset diseases. It is therefore important to define the molecular makeup of adult MNs in animal models and extract organizing principles. Here, we generate a comprehensive molecular atlas of adult Caenorhabditis elegans MNs and a searchable database. Single-cell RNA sequencing of 13,200 cells reveals that ventral nerve cord MNs cluster into 29 molecularly distinct subclasses. Extending C. elegans Neuronal Gene Expression Map and Network (CeNGEN) findings, all MN subclasses are delineated by distinct expression codes of either neuropeptide or transcription factor gene families. Strikingly, combinatorial codes of homeodomain transcription factor genes succinctly delineate adult MN diversity in both C. elegans and mice. Further, molecularly defined MN subclasses in C. elegans display distinct patterns of connectivity. Hence, our study couples the connectivity map of the C. elegans motor circuit with a molecular atlas of its constituent MNs and uncovers organizing principles and conserved molecular codes of adult MN diversity.

The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

Hox gene functions in the C. elegans nervous system: From early patterning to maintenance of neuronal identity

The nervous system emerges from a series of genetic programs that generate a remarkable array of neuronal cell types. Each cell type must acquire a distinct anatomical position, morphology, and function, enabling the generation of specialized circuits that drive animal behavior. How are these diverse cell types and circuits patterned along the anterior-posterior (A-P) axis of the animal body? Hox genes encode transcription factors that regulate cell fate and patterning events along the A-P axis of the nervous system. While most of our understanding of Hox-mediated control of neuronal development stems from studies in segmented animals like flies, mice, and zebrafish, important new themes are emerging from work in a non-segmented animal: the nematode Caenorhabditis elegans. Studies in C. elegans support the idea that Hox genes are needed continuously and across different life stages in the nervous system; they are not only required in dividing progenitor cells, but also in post-mitotic neurons during development and adult life. In C. elegans embryos and young larvae, Hox genes control progenitor cell specification, cell survival, and neuronal migration, consistent with their neural patterning roles in other animals. In late larvae and adults, C. elegans Hox genes control neuron type-specific identity features critical for neuronal function, thereby extending the Hox functional repertoire beyond early patterning. Here, we provide a comprehensive review of Hox studies in the C. elegans nervous system. To relate to readers outside the C. elegans community, we highlight conserved roles of Hox genes in patterning the nervous system of invertebrate and vertebrate animals. We end by calling attention to new functions in adult post-mitotic neurons for these paradigmatic regulators of cell fate.

A DNA nanodevice for mapping sodium at single-organelle resolution

Cellular sodium ion (Na+) homeostasis is integral to organism physiology. Our current understanding of Na+ homeostasis is largely limited to Na+ transport at the plasma membrane. Organelles may also contribute to Na+ homeostasis; however, the direction of Na+ flow across organelle membranes is unknown because organellar Na+ cannot be imaged. Here we report a pH-independent, organelle-targetable, ratiometric probe that reports lumenal Na+. It is a DNA nanodevice containing a Na+-sensitive fluorophore, a reference dye and an organelle-targeting domain. By measuring Na+ at single endosome resolution in mammalian cells and Caenorhabditis elegans, we discovered that lumenal Na+ levels in each stage of the endolysosomal pathway exceed cytosolic levels and decrease as endosomes mature. Further, we find that lysosomal Na+ levels in nematodes are modulated by the Na+/H+ exchanger NHX-5 in response to salt stress. The ability to image subcellular Na+ will unveil mechanisms of Na+ homeostasis at an increased level of cellular detail.

A molecular atlas of adult C. elegans motor neurons reveals ancient diversity delineated by conserved transcription factor codes

Motor neurons (MNs) constitute an ancient cell type targeted by multiple adult-onset diseases. It is therefore important to define the molecular makeup of adult MNs in animal models and extract organizing principles. Here, we generated a comprehensive molecular atlas of adult Caenorhabditis elegans MNs and a searchable database (http://celegans.spinalcordatlas.org). Single-cell RNA-sequencing of 13,200 cells revealed that ventral nerve cord MNs cluster into 29 molecularly distinct subclasses. All subclasses are delineated by unique expression codes of either neuropeptide or transcription factor gene families. Strikingly, we found that combinatorial codes of homeodomain transcription factor genes define adult MN diversity both in C. elegans and mice. Further, molecularly defined MN subclasses in C. elegans display distinct patterns of connectivity. Hence, our study couples the connectivity map of the C. elegans motor circuit with a molecular atlas of its constituent MNs, and uncovers organizing principles and conserved molecular codes of adult MN diversity.

Minimum standards of pelvic exenterative practice: PelvEx Collaborative guideline

This document outlines the important aspects of caring for patients who have been diagnosed with advanced pelvic cancer. It is primarily aimed at those who are establishing a service that adequately caters to this patient group. The relevant literature has been summarized and an attempt made to simplify the approach to management of these complex cases.

Maintenance of neurotransmitter identity by Hox proteins through a homeostatic mechanism

Hox transcription factors play fundamental roles during early patterning, but they are also expressed continuously, from embryonic stages through adulthood, in the nervous system. However, the functional significance of their sustained expression remains unclear. In C. elegans motor neurons (MNs), we find that LIN-39 (Scr/Dfd/Hox4-5) is continuously required during post-embryonic life to maintain neurotransmitter identity, a core element of neuronal function. LIN-39 acts directly to co-regulate genes that define cholinergic identity (e.g., unc-17/VAChT, cho-1/ChT). We further show that LIN-39, MAB-5 (Antp/Hox6-8) and the transcription factor UNC-3 (Collier/Ebf) operate in a positive feedforward loop to ensure continuous and robust expression of cholinergic identity genes. Finally, we identify a two-component design principle for homeostatic control of Hox gene expression in adult MNs: Hox transcriptional autoregulation is counterbalanced by negative UNC-3 feedback. These findings uncover a noncanonical role for Hox proteins during post-embryonic life, critically broadening their functional repertoire from early patterning to the control of neurotransmitter identity.

P-147 LAPAROSCOPIC SURGERY IS SUITABLE FOR MOST PATIENTS FOR INGUINAL HERNIA REPAIR AND IS AN EXCELLENT OPTION IN EXPERT HANDS

Introduction

This study reviews the practice of a high-volume surgeon, comparing laparoscopic and open surgery for inguinal hernia. In suitable patients the default was laparoscopic Totally Extra Peritoneal (TEP) approach.

Materials & Methods

Data from patients referred over 5 years with inguinal hernias was collated prospectively and analysed retrospectively. Short and long-term outcomes of laparoscopic and open repairs were compared.

Results

205 patients underwent repair of 288 hernias (90.7% laparoscopic, 9.3% open). 83 patients underwent bilateral repair (95.2% laparoscopic). 22 patients underwent repair of 27 recurrent hernias (68% laparoscopic).

1 case (0.5%), started laparoscopically was converted to open. Complication rates were 13.4% vs 36.8% in the laparoscopic and open arms respectively (p<0.01): superficial infection (1.6% vs 0%, p=0.58); haematoma (6.3% vs 15.8%, p=0.14); seroma (4.8% vs 5.3%, p=0.94); persisting numbness (0% vs 5.3%, p<0.01) and chronic pain (1.1% vs 0%, p=0.65). No patients suffered mesh infections or explantation.

Mean stay was significantly longer in open group (p=0.03), median stay was 0 nights in both groups. At median follow up 1.8 years (Interquartile-range 0.9–3.6 years) recurrence rate was 1.1% (0 female, 2 male) and 15.8% (1 female, 2 male) in the laparoscopic and open arms respectively (p<0.01). Open surgery was associated with significantly higher risk of recurrence (HR: 16.3, 95% CI: 2.7–97.8, p<0.01).

Conclusions

This series demonstrates the vast majority of inguinal hernias, both primary and recurrent can be treated with laparoscopic TEP repair. Higher recurrence and complication rates were associated with open repair, with a caveat of strong selection bias.

OC-029 LAPAROSCOPIC INGUINAL HERNIA REPAIR IS FEASIBLE IN PATIENTS WHO HAVE HAD PREVIOUS ABDOMINO-PELVIC SURGERY WITH NO INCREASED RISK OF COMPLICATIONS COMPARED TO OPEN REPAIR

Introduction

This study aims to understand whether previous abdomino-pelvic (AP) surgery is a predictor of peri-operative complication in inguinal hernia surgery and if there are discrepancies between laparoscopic or open repairs.

Material & Methods

All patients operated on within a 5-year period were audited and subcategorised based upon history of AP surgery. Patients were also categorised into laparoscopic and open groups. Data collected included complication rates, recurrence rates and readmission within 30 days.

Results

205 patients underwent repair of 288 hernias. 80 (39%) patients had a history of AP surgery. 32 patients suffered a complication (15.6%). 85% of the repairs were laparoscopic in the AP group vs 96.4% in the non-AP group (p=0.02). Complication rates were 17.5% and 14.4% in the AP group and non-AP group respectively (p=0.55). These included superficial infection (0% vs 2.4%, p=0.16), haematoma (11.3% vs 4.8%, p=0.08), seroma (5.0% vs 4.8%, p=0.95), persisting numbness (0% vs 0.8%, p=0.42), and chronic pain (1.3% vs 0.8%, p=0.75). There were no mesh infections or explantation in either arm. A greater proportion of patients in AP group required overnight stays (32.5% vs 21%, p=0.08). At median follow up 1.8 years, recurrence rates were 3.8% vs 1.6%, p=0.33 in AP and non-AP groups respectively.

Conclusions

Laparoscopic inguinal hernia is feasible in most patients with a history of AP surgery. Compared to open repair, there were no significant differences in recurrence or complication rates in patients with previous AP surgery. Therefore, previous AP surgery should not be a contraindication for laparoscopic repair.

P-048 DOES BILATERAL REPAIR INCREASE COMPLICATION RATES COMPARED TO UNILATERAL REPAIR IN PATIENTS UNDERGOING LAPAROSCOPIC TOTALLY EXTRAPERITONEAL INGUINAL HERNIA SURGERY?

Introduction

There is ongoing debate over whether to fix asymptomatic contralateral inguinal hernias during repair of the presenting hernia. This study reviewed the practice of one high-volume hernia surgeon, comparing unilateral and bilateral laparoscopic repairs, to establish if bilateral repair is associated with an increased risk of post-operative complications compared to unilateral repair.

Material & Methods

All patients operated on within a 5-year period were audited and subcategorised depending on whether they underwent unilateral or bilateral repair. Data was collected on complication rates, rates of recurrence, readmission within 30 days and duration of operation.

Results

186 patients underwent repair of 265 hernias. 79 patients underwent bilateral repair. 25 patients suffered a complication (13.4%). Complication rates were 11.2% and 16.5% in the unilateral group and bilateral group respectively (p=0.50). These included superficial infection (1.9% vs 1.3%, p=0.75), haematoma (5.6% vs 7.6%, p=0.59), seroma (2.8 vs 7.6%, p=0.13), and chronic pain (0% vs 2.5%, p=0.01). There were no mesh infections, persisting numbness or explantation in either arm. In both groups, median nights stayed was 0. At median length of follow-up of 1.8 years, recurrence rates were 1.9% vs 0% in the unilateral and bilateral arms respectively (p=0.22).

Conclusions

There was no significant difference in rates of complications between the bilateral and unilateral arms. Opportunistic repair may reduce risk of future surgeries and morbidity and does not appear to be associated with increased complications. Surgeons may wish to consider this when consenting patients.

A light sheet fluorescence microscopy protocol for Caenorhabditis elegans larvae and adults

Light sheet fluorescence microscopy (LSFM) has become a method of choice for live imaging because of its fast acquisition and reduced photobleaching and phototoxicity. Despite the strengths and growing availability of LSFM systems, no generalized LSFM mounting protocol has been adapted for live imaging of post-embryonic stages of C. elegans. A major challenge has been to develop methods to limit animal movement using a mounting media that matches the refractive index of the optical system. Here, we describe a simple mounting and immobilization protocol using a refractive-index matched UV-curable hydrogel within fluorinated ethylene propylene (FEP) tubes for efficient and reliable imaging of larval and adult C. elegans stages.

Partial Ribosomal Nontranscribed Spacer Sequences Distinguish Rhagoletis zephyria (Diptera: Tephritidae) From the Apple Maggot, R. pomonella

The apple maggot, Rhagoletis pomonella (Walsh), was introduced into the apple-growing regions of the Pacific Northwest in the U.S.A. during the past 60-100 yr. Apple maggot (larvae, puparia, and adults) is difficult to distinguish from its morphologically similar sister species, Rhagoletis zephyria Snow, which is native and abundant in the Pacific Northwest. While morphological identifications are common practice, a simple, inexpensive assay based on genetic differences would be very useful when morphological traits are unclear. Here we report nucleotide substitution and insertion-deletion mutations in the nontranscribed spacer (NTS) of the ribosomal RNA gene cistron of R. pomonella and R. zephyria that appear to be diagnostic for these two fly species. Insertion-deletion variation is substantial and results in a 49 base-pair difference in PCR amplicon size between R. zephyria and R. pomonella that can be scored using agarose gel electrophoresis. PCR amplification and DNA sequencing of 766 bp of the NTS region from 38 R. pomonella individuals and 35 R. zephyria individuals from across their geographic ranges led to the expected PCR fragments of approx. 840 bp and 790 bp, respectively, as did amplification and sequencing of a smaller set of 26 R. pomonella and 16 R. zephyria flies from a sympatric site in Washington State. Conversely, 633 bp mitochondrial COI barcode sequences from this set of flies were polyphyletic with respect to R. pomonella and R. zephyria. Thus, differences in NTS PCR products on agarose gels potentially provide a simple way to distinguish between R. pomonella and R. zephyria.

The SWI/SNF chromatin remodeling assemblies BAF and PBAF differentially regulate cell cycle exit and cellular invasion in vivo

Chromatin remodelers such as the SWI/SNF complex coordinate metazoan development through broad regulation of chromatin accessibility and transcription, ensuring normal cell cycle control and cellular differentiation in a lineage-specific and temporally restricted manner. Mutations in genes encoding the structural subunits of chromatin, such as histone subunits, and chromatin regulating factors are associated with a variety of disease mechanisms including cancer metastasis, in which cancer co-opts cellular invasion programs functioning in healthy cells during development. Here we utilize Caenorhabditis elegans anchor cell (AC) invasion as an in vivo model to identify the suite of chromatin agents and chromatin regulating factors that promote cellular invasiveness. We demonstrate that the SWI/SNF ATP-dependent chromatin remodeling complex is a critical regulator of AC invasion, with pleiotropic effects on both G₀ cell cycle arrest and activation of invasive machinery. Using targeted protein degradation and enhanced RNA interference (RNAi) vectors, we show that SWI/SNF contributes to AC invasion in a dose-dependent fashion, with lower levels of activity in the AC corresponding to aberrant cell cycle entry and increased loss of invasion. Our data specifically implicate the SWI/SNF BAF assembly in the regulation of the G₀ cell cycle arrest in the AC, whereas the SWI/SNF PBAF assembly promotes AC invasion via cell cycle-independent mechanisms, including attachment to the basement membrane (BM) and activation of the pro-invasive fos-1/FOS gene. Together these findings demonstrate that the SWI/SNF complex is necessary for two essential components of AC invasion: arresting cell cycle progression and remodeling the BM. The work here provides valuable single-cell mechanistic insight into how the SWI/SNF assemblies differentially contribute to cellular invasion and how SWI/SNF subunit-specific disruptions may contribute to tumorigeneses and cancer metastasis.

Cellular invasion is required for animal development and homeostasis. Inappropriate activation of invasion however can result in cancer metastasis. Invasion programs are orchestrated by complex gene regulatory networks (GRN) that function in a coordinated fashion to turn on and off pro-invasive genes. While the core of GRNs are DNA binding transcription factors, they require aid from chromatin remodelers to access the genome. To identify the suite of pro-invasive chromatin remodelers, we paired high resolution imaging with RNA interference to individually knockdown 269 chromatin factors, identifying the evolutionarily conserved SWItching defective/Sucrose Non-Fermenting (SWI/SNF) ATP-dependent chromatin remodeling complex as a new regulator of Caenorhabditis elegans anchor cell (AC) invasion. Using a combination of CRISPR/Cas9 genome engineering and targeted protein degradation we demonstrate that the core SWI/SNF complex functions in a dose-dependent manner to control invasion. Further, we determine that the accessory SWI/SNF complexes, BAF and PBAF, contribute to invasion via distinctive mechanisms: BAF is required to prevent inappropriate proliferation while PBAF promotes AC attachment and remodeling of the basement membrane. Together, our data provide insights into how the SWI/SNF complex, which is mutated in many human cancers, can function in a dose-dependent fashion to regulate switching from invasive to proliferative fates.

Visualizing the metazoan proliferation-quiescence decision in vivo

Cell proliferation and quiescence are intimately coordinated during metazoan development. Here, we adapt a cyclin-dependent kinase (CDK) sensor to uncouple these key events of the cell cycle in Caenorhabditis elegans and zebrafish through live-cell imaging. The CDK sensor consists of a fluorescently tagged CDK substrate that steadily translocates from the nucleus to the cytoplasm in response to increasing CDK activity and consequent sensor phosphorylation. We show that the CDK sensor can distinguish cycling cells in G1 from quiescent cells in G0, revealing a possible commitment point and a cryptic stochasticity in an otherwise invariant C. elegans cell lineage. Finally, we derive a predictive model of future proliferation behavior in C. elegans based on a snapshot of CDK activity in newly born cells. Thus, we introduce a live-cell imaging tool to facilitate in vivo studies of cell-cycle control in a wide-range of developmental contexts.

Postoperative chemotherapy improves survival in patients with resected high-risk Stage II colorectal cancer: results of a systematic review and meta-analysis

AIM

The aim was to assess the benefit of adjuvant chemotherapy in high-risk Stage II colorectal cancer.

METHOD

A systematic literature review and meta-analysis was performed comparing survival in patients with resected Stage II colorectal cancer and high-risk features having postoperative chemotherapy vs no chemotherapy.

RESULTS

Of 1031 articles screened, 29 were included, reporting on 183 749 participants. Adjuvant chemotherapy significantly improved overall survival [hazard ratio (HR) 0.61, P < 0.0001], disease-specific survival (HR = 0.73, P = 0.05) and disease-free survival (HR = 0.59, P < 0.0001) compared to no chemotherapy. Adjuvant chemotherapy significantly increased 5-year overall survival (OR = 0.53, P = 0.0008) and 5-year disease-free survival (OR = 0.50, P = 0.001). Overall survival and disease-free survival remained significantly prolonged during subgroup analysis of studies published from 2015 onwards (HR = 0.60, P < 0.0001; HR = 0.65, P = 0.0001; respectively), in patients with two or more high-risk features (HR = 0.59, P = 0.0001; HR = 0.70, P = 0.03; respectively) and in colon cancer (HR = 0.61, P < 0.0001; HR = 0.51, P = 0.0001; respectively). Overall survival, disease-specific survival and disease-free survival during subgroup analysis of individual high-risk features were T4 tumour (HR = 0.58, P < 0.0001; HR = 0.50, P = 0.003; HR = 0.75, P = 0.05), < 12 lymph nodes harvested (HR = 0.67, P = 0.0002; HR = 0.80, P = 0.17; HR = 0.72, P = 0.02), poor differentiation (HR = 0.84, P = 0.35; HR = 0.85, P = 0.23; HR = 0.61, P = 0.41), lymphovascular or perineural invasion (HR = 0.55, P = 0.05; HR = 0.59, P = 0.11; HR = 0.76, P = 0.05) and emergency surgery (HR = 0.60, P = 0.02; HR = 0.68, P = 0.19).

CONCLUSION

Adjuvant chemotherapy in high-risk Stage II colorectal cancer results in a modest survival improvement and should be considered on an individual patient basis. Due to potential heterogeneity and selection bias of the included studies, and lack of separate rectal cancer data, further large randomized trials with predefined inclusion criteria and standardized chemotherapy regimens are required.

Identification of immune and non-immune cells in regenerating axolotl limbs by single-cell sequencing

Immune cells are known to be critical for successful limb regeneration in the axolotl (Ambystoma mexicanum), but many details regarding their identity, behavior, and function are yet to be resolved. We isolated peripheral leukocytes from the blood of adult axolotls and then created two samples for single-cell sequencing: 1) peripheral leukocytes (N = 7889) and 2) peripheral leukocytes with presumptive macrophages from the intraperitoneal cavity (N = 4998). Using k-means clustering, we identified 6 cell populations from each sample that presented gene expression patterns indicative of erythrocyte, thrombocyte, neutrophil, B-cell, T-cell, and myeloid cell populations. A seventh, presumptive macrophage cell population was identified uniquely from sample 2. We then isolated cells from amputated axolotl limbs at 1 and 6 days post-amputation (DPA) and performed single cell sequencing (N = 8272 and 9906 cells respectively) to identify immune and non-immune cell populations. Using k-means clustering, we identified 8 cell populations overall, with the majority of cells expressing erythrocyte-specific genes. Even though erythrocytes predominated, we used an unbiased approach to identify infiltrating neutrophil, macrophage, and lymphocyte populations at both time points. Additionally, populations expressing genes for epidermal cells, fibroblast-like cells, and endothelial cells were also identified. Consistent with results from previous experimental studies, neutrophils were more abundant at 1 DPA than 6 DPA, while macrophages and non-immune cells exhibited inverse abundance patterns. Of note, we identified a small population of fibroblast-like cells at 1 DPA that was represented by considerably more cells at 6 DPA. We hypothesize that these are early progenitor cells that give rise to the blastema. The enriched gene sets from our work will aid future single-cell investigations of immune cell diversity and function during axolotl limb regeneration.

Risk factors associated with progression to referable retinopathy: a type 2 diabetes mellitus cohort study in the Republic of Ireland

AIM

To determine factors associated with progression to referable diabetic retinopathy in people with type 2 diabetes in the Republic of Ireland.

RESEARCH DESIGN AND METHODS

The study was conducted in a dynamic cohort of 2770 people with type 2 diabetes, recruited between April 2005 and July 2013. Systemic factors (systolic and diastolic blood pressure, HbA_1c , lipid levels, BMI) and baseline diabetic retinopathy grading results were evaluated at 4-monthly and yearly intervals, respectively. Associations between risk factors (most recently recorded value, and rate of change in value between pairs of consecutive systemic evaluations) and development of referable diabetic retinopathy were estimated using Cox proportional hazards models.

RESULTS

There was a fourfold increased risk of progression to referral when retinopathy was present at baseline vs no retinopathy at baseline (hazard ratio 4.02, 95% CI 2.80-5.78; P<0.001). Higher current values of HbA_1c (hazard ratio 1.22, 95% CI 1.11-1.34; P<0.001), systolic blood pressure (hazard ratio 1.29, 95% CI 1.15-1.45; P<0.001) and triglycerides (hazard ratio 1.10, 95% CI 1.03-1.18; P=0.004) were associated with increased risk of referral. Higher current BMI (hazard ratio 0.83, 95% CI 0.73-0.95; P=0.007) and diastolic blood pressure (hazard ratio 0.91, 95% CI 0.85-0.97; P=0.006) were associated with reduced risk of referral.

CONCLUSIONS

Presence of retinopathy at baseline was strongly associated with increased risk of referral. Modest associations between systemic factors and risk of progression to referable retinopathy were detected.

A developmental gene regulatory network for C. elegans anchor cell invasion

Cellular invasion is a key part of development, immunity and disease. Using an in vivo model of Caenorhabditis elegans anchor cell invasion, we characterize the gene regulatory network that promotes cell invasion. The anchor cell is initially specified in a stochastic cell fate decision mediated by Notch signaling. Previous research has identified four conserved transcription factors, fos-1 (Fos), egl-43 (EVI1/MEL), hlh-2 (E/Daughterless) and nhr-67 (NR2E1/TLX), that mediate anchor cell specification and/or invasive behavior. Connections between these transcription factors and the underlying cell biology that they regulate are poorly understood. Here, using genome editing and RNA interference, we examine transcription factor interactions before and after anchor cell specification. Initially, these transcription factors function independently of one another to regulate LIN-12 (Notch) activity. Following anchor cell specification, egl-43, hlh-2 and nhr-67 function largely parallel to fos-1 in a type I coherent feed-forward loop with positive feedback to promote invasion. Together, these results demonstrate that the same transcription factors can function in cell fate specification and differentiated cell behavior, and that a gene regulatory network can be rapidly assembled to reinforce a post-mitotic, pro-invasive state.

Changes in the multidisciplinary management of rectal cancer from 2009 to 2015 and associated improvements in short-term outcomes

AIM

Significant recent changes in management of locally advanced rectal cancer (LARC) include preoperative staging, use of extended neoadjuvant therapies and minimally invasive surgery (MIS). This study was aimed at characterizing these changes and associated short-term outcomes.

METHOD

We retrospectively analysed treatment and outcome data from patients with T3/4 or N+ LARC ≤ 15 cm from the anal verge who were evaluated at a comprehensive cancer centre in 2009-2015.

RESULTS

In total, 798 patients were identified and grouped into five cohorts based on treatment year: 2009-2010, 2011, 2012, 2013 and 2014-2015. Temporal changes included increased reliance on MRI staging, from 57% in 2009-2010 to 98% in 2014-2015 (P < 0.001); increased use of total neoadjuvant therapy, from 17% to 76% (P < 0.001); and increased use of MIS, from 33% to 70% (P < 0.001). Concurrently, median hospital stay decreased (from 7 to 5 days; P < 0.001), as did the rates of Grade III-V complications (from 13% to 7%; P < 0.05), surgical site infections (from 24% to 8%; P < 0.001), anastomotic leak (from 11% to 3%; P < 0.05) and positive circumferential resection margin (from 9% to 4%; P < 0.05). TNM downstaging increased from 62% to 74% (P = 0.002).

CONCLUSION

Shifts toward MRI-based staging, total neoadjuvant therapy and MIS occurred between 2009 and 2015. Over the same period, treatment responses improved, and lengths of stay and the incidence of complications decreased.

Effectiveness of a multidisciplinary patient care bundle for reducing surgical-site infections

BACKGROUND

Surgical-site infection (SSI) is associated with significant healthcare costs. To reduce the high rate of SSI among patients undergoing colorectal surgery at a cancer centre, a comprehensive care bundle was implemented and its efficacy tested.

METHODS

A pragmatic study involving three phases (baseline, implementation and sustainability) was conducted on patients treated consecutively between 2013 and 2016. The intervention included 13 components related to: bowel preparation; oral and intravenous antibiotic selection and administration; skin preparation, disinfection and hygiene; maintenance of normothermia during surgery; and use of clean instruments for closure. SSI risk was evaluated by means of a preoperative calculator, and effectiveness was assessed using interrupted time-series regression.

RESULTS

In a population with a mean BMI of 30 kg/m² , diabetes mellitus in 17·5 per cent, and smoking history in 49·3 per cent, SSI rates declined from 11·0 to 4·1 per cent following implementation of the intervention bundle (P = 0·001). The greatest reductions in SSI rates occurred in patients at intermediate or high risk of SSI: from 10·3 to 4·7 per cent (P = 0·006) and from 19 to 2 per cent (P < 0·001) respectively. Wound care modifications were very different in the implementation phase (43·2 versus 24·9 per cent baseline), including use of an overlying surface vacuum dressing (17·2 from 1·4 per cent baseline) or leaving wounds partially open (13·2 from 6·7 per cent baseline). As a result, the biggest difference was in wound-related rather than organ-space SSI. The median length of hospital stay decreased from 7 (i.q.r. 5-10) to 6 (5-9) days (P = 0·002). The greatest reduction in hospital stay was seen in patients at high risk of SSI: from 8 to 6 days (P < 0·001). SSI rates remained low (4·5 per cent) in the sustainability phase.

CONCLUSION

Meaningful reductions in SSI can be achieved by implementing a multidisciplinary care bundle at a hospital-wide level.

Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis

OBJECTIVE

The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions.

METHODS

A systematic search was performed to identify randomized controlled trials targeting adolescents (age: ≥10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored.

RESULTS

Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects.

CONCLUSION

Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols.

Rapid, specific, simple, in-field detection of Xanthomonas campestris pathovar musacearum by loop-mediated isothermal amplification

AIMS

To develop and evaluate a loop-mediated isothermal amplification (LAMP) assay for Xanthomonas campestris pathovar musacearum (Xcm), the causal agent of banana Xanthomonas wilt, a major disease of banana in Africa.

METHODS AND RESULTS

LAMP primers were designed to the general secretion pathway protein D gene and tested against 17 isolates of Xcm encompassing the known genetic and geographic diversity of the bacterium and all isolates were detected. Seventeen other Xanthomonas isolates, including closely related Xanthomonas vasicola, other bacterial pathogens/endophytes of Musa and two healthy Musa varieties gave negative results with the LAMP assay. The assay showed good sensitivity, detecting as little as 51 fg of Xcm DNA, a greater level of sensitivity than that of an Xcm PCR assay. Amplification with the LAMP assay was very rapid, typically within 9 min from bacterial cultures. Symptomatic field samples of Musa from Uganda were tested and all produced amplification in less than 13 min.

CONCLUSIONS

The LAMP assay provides rapid, sensitive detection of the pathogen that is ideally suited for deployment in laboratories with basic facilities and in-field situations.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first LAMP assay for Xcm which provides a significant improvement compared to existing diagnostics.

A comparison of health-related quality of life of patients with primary and recurrent varicose veins

Aim: To determine whether recurrent varicose veins affect patient quality of life. The health-related quality of life (HRQL) scores of patients with recurrent varicose veins were compared with those of patients presenting with primary varicose vein disease.

Methods: HRQL among patients attending outpatient appointments for recurrent and primary varicose veins was measured using the Aberdeen Varicose Vein Questionnaire (AVVQ) and the Short Form-36 General Health Survey (SF-36).

Results: Questionnaires were given to 211 patients (150 primary, 61 recurrent), and 194 (133 primary, 61 recurrent) completed them. For the AVVQ, patients with recurrent varicose veins had significantly worse symptom scores compared with those with primary disease (24.87 ± 12.28 vs 17.77 ± 9.68, Mann-Whitney, P <0.01). The SF-36 recorded significantly worse HRQL (Mann-Whitney, P <0.05) for patients with recurrent varicose veins compared with those with primary varicose veins in all but one of the eight domains (role limitation attributed to emotional problems, RE, P = 0.073).

Conclusion: Varicose vein recurrence is associated with a significantly worse HRQL than is found among patients with primary varicose veins.

Randomized clinical trial of varicose vein surgery with compression versus compression alone for the treatment of venous ulceration

Objectives: No randomized controlled trials exist to show whether varicose vein surgery improves healing of venous ulcers. In this study we investigated whether superficial venous surgery gave additional benefit to compression therapy in terms of healing rate, time to healing and quality of life of patients with venous ulcers.

Methods: A total of 121 consecutive patients with venous ulceration were identified, of which 45 were unfit/unwilling to be included. The remaining 76 (aged 38-89, 39 female) were randomized to receive either four-layer bandaging ( n =39) or superficial venous surgery (long and short saphenous with or without perforator surgery) and four-layer bandaging ( n =37). Ulcer healing and health-related quality of life (HRQL) were assessed.

Results: The healing rate was 64% (25/39) in the compression treatment group and 68% (25/37) in the surgical treatment group. This difference was not statistically significant (Pearson 2 P=0.75). There was no significant difference between the time to ulcer healing in the two treatment groups (log rank statistic=0.69, P value=0.41): median time 83 days for surgery vs 98 days for compression. After adjusting for duration of ulcer, size of ulcer and previous deep vein thrombosis, there was still no significant difference between time to healing for the two treatment groups (adjusted hazard ratio=0.79, 95% confidence interval 0.45-1.39). There was no difference in HRQL between the two groups, using the scores of a disease-specific questionnaire (CXVUQ).

Conclusions: This study suggests that for venous ulceration, superficial venous surgery gives no additional benefit to compression therapy from the point of view of healing rate and quality of life.

Myeloid translocation genes differentially regulate colorectal cancer programs

Myeloid translocation genes (MTGs), originally identified as chromosomal translocations in acute myelogenous leukemia, are transcriptional corepressors that regulate hematopoietic stem cell programs. Analysis of The Cancer Genome Atlas (TCGA) database revealed that MTGs were mutated in epithelial malignancy and suggested that loss of function might promote tumorigenesis. Genetic deletion of MTGR1 and MTG16 in the mouse has revealed unexpected and unique roles within the intestinal epithelium. Mtgr1^−/− mice have progressive depletion of all intestinal secretory cells, and Mtg16^−/− mice have a decrease in goblet cells. Furthermore, both Mtgr1^−/− and Mtg16^−/− mice have increased intestinal epithelial cell proliferation. We thus hypothesized that loss of MTGR1 or MTG16 would modify Apc^1638/+-dependent intestinal tumorigenesis. Mtgr1^−/− mice, but not Mtg16^−/− mice, had a 10-fold increase in tumor multiplicity. This was associated with more advanced dysplasia, including progression to invasive adenocarcinoma, and augmented intratumoral proliferation. Analysis of ChIP-seq datasets for MTGR1 and MTG16 targets indicated that MTGR1 can regulate Wnt and Notch signaling. In support of this, immunohistochemistry and gene expression analysis revealed that both Wnt and Notch signaling pathways were hyperactive in Mtgr1^−/− tumors. Furthermore, in human colorectal cancer (CRC) samples MTGR1 was downregulated at both the transcript and protein level. Overall our data indicates that MTGR1 has a context dependent effect on intestinal tumorigenesis.

The early management of the burned patient in the Naval service

Burns represent a perpetual threat in military combat and are a pervasive threat in the land, maritime and air arenas. Therefore, it is imperative that military clinicians are well versed in managing burns in order to ensure optimal survival and recovery. This article aims to explore the epidemiology, pathophysiology, assessment and early management of the burned patient with a focus on the austere maritime environment and current military guidance.

Risk stratification by the Appendicitis Inflammatory Response score to guide decision-making in patients with suspected appendicitis

BACKGROUND

Current management of suspected appendicitis is hampered by the overadmission of patients with non-specific abdominal pain and a significant negative exploration rate. The potential benefits of risk stratification by the Appendicitis Inflammatory Response (AIR) score to guide clinical decision-making were assessed.

METHODS

During this 50-week prospective observational study at one institution, the AIR score was calculated for all patients admitted with suspected appendicitis. Appendicitis was diagnosed by histological examination, and patients were classified as having non-appendicitis pain if histological findings were negative or surgery was not performed. The diagnostic performance of the AIR score and the potential for risk stratification to reduce admissions, optimize imaging and prevent unnecessary explorations were quantified.

RESULTS

A total of 464 patients were included, of whom 210 (63·3 per cent) with non-appendicitis pain were correctly classified as low risk. However, 13 low-risk patients had appendicitis. Low-risk patients accounted for 48·1 per cent of admissions (223 of 464), 57 per cent of negative explorations (48 of 84) and 50·7 per cent of imaging requests (149 of 294). An AIR score of 5 or more (intermediate and high risk) had high sensitivity for all severities of appendicitis (90 per cent) and also for advanced appendicitis (98 per cent). An AIR score of 9 or more (high risk) was very specific (97 per cent) for appendicitis, and the majority of patients with appendicitis in the high-risk group (21 of 30, 70 per cent) had perforation or gangrene. Ultrasound imaging could not exclude appendicitis in low-risk patients (negative likelihood ratio (LR) 1·0) but could rule-in the diagnosis in intermediate-risk patients (positive LR 10·2). CT could exclude appendicitis in low-risk patients (negative LR 0·0) and rule-in appendicitis in the intermediate group (positive LR 10·9).

CONCLUSION

Risk stratification of patients with suspected appendicitis by the AIR score could guide decision-making to reduce admissions, optimize utility of diagnostic imaging and prevent negative explorations.

The early management of the burned patient in the Naval service

Burns represent a perpetual threat in military combat and are a pervasive threat in the land, maritime and air arenas. Therefore, it is imperative that military clinicians are well versed in managing burns in order to ensure optimal survival and recovery. This article aims to explore the epidemiology, pathophysiology, assessment and early management of the burned patient with a focus on the austere maritime environment and current military guidance.

Experts reviews of the multidisciplinary consensus conference colon and rectal cancer 2012: science, opinions and experiences from the experts of surgery

The first multidisciplinary consensus conference on colon and rectal cancer was held in December 2012, achieving a majority of consensus for diagnostic and treatment decisions using the Delphi Method. This article will give a critical appraisal of the topics discussed during the meeting and in the consensus document by well-known leaders in surgery that were involved in this multidisciplinary consensus process. Scientific evidence, experience and opinions are collected to support multidisciplinary teams (MDT) with arguments for medical decision-making in diagnosis, staging and treatment strategies for patients with colon or rectal cancer. Surgery is the cornerstone of curative treatment for colon and rectal cancer. Standardizing treatment is an effective instrument to improve outcome of multidisciplinary cancer care for patients with colon and rectal cancer. In this article, a review of the following focuses; Perioperative care, age and colorectal surgery, obstructive colorectal cancer, stenting, surgical anatomical considerations, total mesorectal excision (TME) surgery and training, surgical considerations for locally advanced rectal cancer (LARC) and local recurrent rectal cancer (LRRC), surgery in stage IV colorectal cancer, definitions of quality of surgery, transanal endoscopic microsurgery (TEM), laparoscopic colon and rectal surgery, preoperative radiotherapy and chemoradiotherapy, and how about functional outcome after surgery?

A comparative study of colorectal surgical outcome in a national audit separated by 15 years

AIM

The Wales-Trent Bowel Cancer Audit (WTBA) was carried out in 1993, and since 2001 Welsh Bowel Cancer Audits (WBCA) have taken place annually. Screening for bowel cancer in Wales was introduced in 2008. This study compared patient variables, the role of surgery and operative mortality rates over the 15-year interval between the WTBA and the last WBCA before the introduction of population screening.

METHOD

Data from the WTBA in 1993 were compared with those of the WBCA including patients diagnosed between April 2007 and March 2008.

RESULTS

In 1993, 1536 patients were diagnosed with colorectal cancer (CRC) compared with 1793 in 2007-2008. Patient demographics and American Society of Anesthesiology (ASA) score did not change during these periods. Surgical treatment for CRC decreased (93% in 1993 vs 80% in 2007-2008; P < 0.001) particularly in the use of resectional surgery (84% in 1993 vs 71% in 2007-2008; P < 0.001). The 30-day postoperative mortality rate fell from 7.4% in 1993 to 5.9% in 2007-2008 (P = 0.097). Advanced disease at operation was more prevalent in the WTBA (25% of all operated patients were Stage IV in 1993 vs 13% in 2007-2008; P < 0.001). The use of surgery in patients with metastatic disease also declined over this period.

CONCLUSION

Surgery is used less frequently in the management of CRC compared with 15 years previously, and is a factor in the reduction of the interpreted 30-day operative mortality.

Utilization and optimization of a waste stream cellulose culture medium for pigment production by Penicillium spp

AIMS

This research sought to determine optimal corn waste stream-based fermentation medium C and N sources and incubation time to maximize pigment production by an indigenous Indonesian Penicillium spp., as well as to assess pigment pH stability.

METHODS AND RESULTS

A Penicillium spp. was isolated from Indonesian soil, identified as Penicillium resticulosum, and used to test the effects of carbon and nitrogen type and concentrations, medium pH, incubation period and furfural on biomass and pigment yield (PY) in a waste corncob hydrolysate basal medium. Maximum red PY (497.03 ± 55.13 mg l(-1)) was obtained with a 21 : 1 C : N ratio, pH 5.5-6.0; yeast extract-, NH(4) NO(3)-, NaNO(3)-, MgSO(4) ·7H(2) O-, xylose- or carboxymethylcellulose (CMC)-supplemented medium and 12 days (25 °C, 60-70% relative humidity, dark) incubation. C source, C, N and furfural concentration, medium pH and incubation period all influenced biomass and PY. Pigment was pH 2-9 stable.

CONCLUSIONS

Penicillium resticulosum demonstrated microbial pH-stable-pigment production potential using a xylose or CMC and N source, supplemented waste stream cellulose culture medium.

SIGNIFICANCE AND IMPACT OF THE STUDY

Corn derived, waste stream cellulose can be used as a culture medium for fungal pigment production. Such application provides a process for agricultural waste stream resource reuse for production of compounds in increasing demand.

Development of a social morbidity score in patients with chronic ulcerative colitis as a potential guide to treatment

AIM

Present quality of life instruments for inflammatory bowel disease do not evaluate many social aspects of patients' lives that are potentially important in clinical decision making. We have developed a new Social Impact of Chronic Conditions - Inflammatory Bowel Disease (SICC-IBD) questionnaire to assess these areas.

METHOD

A 34-item questionnaire was piloted to determine quality of life relating to education, personal relationships, employment, independence and finance. It was compared with the Short Form 36-Item version 2 (SF-36v2) and the Inflammatory Bowel Disease Questionnaire (IBDQ) in 150 patients with chronic ulcerative colitis on an endoscopic surveillance register who had never had surgery.

RESULTS

Reliability and validity testing enabled the questionnaire to be shortened to only eight items. There was a high level of reliability (Cronbach's α=0.72). The questionnaire correlated well with the social functioning domain of the SF-36 (rs=0.56) and was able to distinguish clinical severity of disease.

CONCLUSION

The SICC-IBD is a new tool for assessment of patients with ulcerative colitis, which has identified new aspects of social disability for further study and for potential use as an additional tool in therapy decisions.

The National Bowel Cancer Audit: the risks and benefits of moving to open reporting of clinical outcomes

BACKGROUND

The government's proposals to openly report clinical outcomes poses challenges to the National Bowel Cancer Audit now funded by the UK department of health.

AIM

To identify the benefits and risks of open reporting and to propose ways the risks might be minimized.

METHODS

A review of the literature on clinical audit and the consequences of open reporting.

RESULTS

There are significant potential benefits of a national audit of bowel cancer including protecting patients from sub-standard care, providing clinicians with externally validated evidence of their performance, outcome data for clinical governance and evidence that increases in government expenditure are achieving improvements in survival from bowel cancer. These benefits will only be achieved if the audit captures most of the cases of bowel cancer in the UK, the data collected is complete and accurate, the results are risk adjusted and these are presented to the public in a way that is fair, clear and understandable. Involvement of clinicians who have confidence in the results of the audit and who actively compare their own results against a national standard is essential. It is suggested that a staged move to open reporting should minimise the risk of falsely identifying an outlying unit.

CONCLUSION

The fundamental aim of the National Bowel Cancer Audit is the pursuit of excellence by identification and adoption of best practice. This could achieve a continuous improvement in the care of all patients with bowel cancer in the UK. The ACPGBI suggests a safer way of transition to open reporting to avoid at least some of its pitfalls.

Short interval time measurement by a parasitoid wasp

The number of eggs laid by the parasitoid wasp Trichogramma varies with host volume. The duration of the wasp's initial transit across the host surface during host examination is used to determine the number of eggs laid. A 2.5-second reduction in initial transit resulted in a 30% reduction in eggs oviposited, demonstrating that these wasps measure short time intervals. This measure is used for progeny allocation independent of host body size.

Genome biology of the cyclostomes and insights into the evolutionary biology of vertebrate genomes

The jawless vertebrates (lamprey and hagfish) are the closest extant outgroups to all jawed vertebrates (gnathostomes) and can therefore provide critical insight into the evolution and basic biology of vertebrate genomes. As such, it is notable that the genomes of lamprey and hagfish possess a capacity for rearrangement that is beyond anything known from the gnathostomes. Like the jawed vertebrates, lamprey and hagfish undergo rearrangement of adaptive immune receptors. However, the receptors and the mechanisms for rearrangement that are utilized by jawless vertebrates clearly evolved independently of the gnathostome system. Unlike the jawed vertebrates, lamprey and hagfish also undergo extensive programmed rearrangements of the genome during embryonic development. By considering these fascinating genome biologies in the context of proposed (albeit contentious) phylogenetic relationships among lamprey, hagfish, and gnathostomes, we can begin to understand the evolutionary history of the vertebrate genome. Specifically, the deep shared ancestry and rapid divergence of lampreys, hagfish and gnathostomes is considered evidence that the two versions of programmed rearrangement present in lamprey and hagfish (embryonic and immune receptor) were present in an ancestral lineage that existed more than 400 million years ago and perhaps included the ancestor of the jawed vertebrates. Validating this premise will require better characterization of the genome sequence and mechanisms of rearrangement in lamprey and hagfish.

Bacteriocin Typing of Burkholderia (Pseudomonas) solanacearum Race 1 of the French West Indies and Correlation with Genomic Variation of the Pathogen

Burkholderia solanacearum race 1 isolates indigenous to the French West Indies were characterized by bacteriocin typing and two genomic fingerprinting methods: pulsed-field gel electrophoresis of genomic DNA digested by rare-cutting restriction endonucleases (RC-PFGE) and PCR with primers corresponding to repetitive extragenic palindromic (REP), enterobacterial repetitive intergenic consensus (ERIC), and BOX elements (collectively known as rep-PCR). The survey comprised 24 reference strains and 65 isolates obtained from a field trial in Guadeloupe in 1993. Comparison of the data identified RC-PFGE as the most discriminatory method, delineating 17 pulsed-field gel profile types. rep-PCR and bacteriocin typing identified nine rep-PCR profile types and nine bacteriocin groups. Independent determination of similarity coefficients and clustering of RC-PFGE and rep-PCR data identified six groups common to both sets of data that correlated to biovar and bacteriocin groups. Further study of bacteriocin production in planta gave results consistent with in vitro bacteriocin typing. It was observed that spontaneous bacteriocin-resistant mutants exhibited a cross-resistance to other bacteriocins as identified by the typing scheme and that such mutants possessed a selective advantage for growth over isogenic nonmutants in the presence of a bacteriocin. The results are significant in the search for biological control of disease by nonpathogenic mutants of the wild-type organism.

Long-term failure and function after restorative proctocolectomy - a multi-centre study of patients from the UK National Ileal Pouch Registry

OBJECTIVE

There is little information on the long-term failure and function after restorative proctocolectomy (RPC). The results of data submitted to a national registry were analysed.

METHOD

The UK National Pouch Registry was established in 2004. By 2006, it comprised data collected from ten centres between 1976 and 2006. The long-term failure and functional outcome were determined. Trends over time were assessed using the gamma statistic or the Kruskal-Wallis statistic wherever appropriate.

RESULTS

In all, 2491 patients underwent primary RPC over a median of 54 months (range 1 month to 28.9 years). Of these, 127 (5.1%) underwent abdominal salvage surgery. The incidence of failure (excision or indefinite diversion) was 7.7% following primary and 27.5% following salvage RPC (P < 0.001). The median frequency of defaecation/24 h was five including one at night. Nocturnal seepage occurred in 8% at 1 year, rising to 15.4% at 20 years (P = 0.037). Urgency was experienced by 5.1% of patients at 1 year rising to 9.1% at 15 years (P = 0.022). Stool frequency and the need for antidiarrhoeal medication were greater following salvage RPC.

CONCLUSION

In patients retaining anal function after RPC, frequency of defaecation was stable over 20 years. Faecal urgency and minor incontinence worsened with time. Function after salvage RPC was significantly worse.

Recurrent nuclear DNA introgression accompanies chloroplast DNA exchange between two eucalypt species

Numerous studies within plant genera have found geographically structured sharing of chloroplast (cp) DNA among sympatric species, consistent with introgressive hybridization. Current research is aimed at understanding the extent, direction and significance of nuclear (nr) DNA exchange that accompanies putative cpDNA exchange. Eucalyptus is a complex tree genus for which cpDNA sharing has been established between multiple species. Prior phylogeographic analysis has indicated cpDNA introgression into the widespread forest species Eucalyptus globulus from its rare congener E. cordata. In this study, we use AFLP markers to characterize corresponding nrDNA introgression, on both a broad and fine spatial scale. Using 388 samples we examine (i) the fine-scale spatial structure of cp and nrDNA introgression from E. cordata into E. globulus at a site in natural forest and (ii) broad-scale patterns of AFLP marker introgression at six additional mixed populations. We show that while E. globulus and E. cordata retain strongly differentiated nuclear gene pools overall, leakage of nrDNA occurs at mixed populations, with some AFLP markers being transferred to E. globulus recurrently at different sites. On the fine scale, different AFLP fragments show varying distances of introgression into E. globulus, while introgression of cpDNA is extensive. The frequency of E. cordata markers in E. globulus is correlated with spatial proximity to E. cordata, but departs from expectations based on AFLP marker frequency in E. cordata, indicating that selection may be governing the persistence of introgressed fragments in E. globulus.

Some aspects of the gross and fine structure of the amphibian papilla in the labyrinth of the newt, Triturus cristatus

Each receptor cell in the sensory macula bears a number of stereocilia and one peripherally located kinocilium; in the two halves of the macula, the kinocilia lie on opposite sides of their associated stereocilia. The morphological axes of the receptor cells are approximately parallel to the long axis of the papilla. The gelatinous cupula overlying the macula extends almost to the opposite wall of the papilla. These structural features are discussed in connection with both the proposed function of the papilla as a vibration detector and the possible evolutionary relationships with other acousticolateralis receptors.

HDAC inhibitors regulate claudin-1 expression in colon cancer cells through modulation of mRNA stability

Expression and cellular distribution of claudin-1, a tight junction protein, is dysregulated in colon cancer and its overexpression in colon cancer cells induced dedifferentiation and increased invasion. However, the molecular mechanism(s) underlying dysregulated claudin-1 expression in colon cancer remains poorly understood. Histone deacetylase (HDAC)-dependent histone acetylation is an important mechanism of the regulation of cancer-related genes and inhibition of HDACs induces epithelial differentiation and decreased invasion. Therefore, in this study, we examined the role of HDAC-dependent epigenetic regulation of claudin-1 in colon cancer. In this study, we show that sodium butyrate and Trichostatin A (TSA), two structurally different and widely used HDAC inhibitors, inhibited claudin-1 expression in multiple colon cancer cell lines. Further studies revealed modulation of claudin-1 mRNA stability by its 3'-UTR as the major mechanism underlying HDAC-dependent claudin-1 expression. In addition, overexpression of claudin-1 abrogated the TSA-induced inhibition of invasion in colon cancer cells suggesting functional crosstalk. Analysis of mRNA expression in colon cancer patients, showed a similar pattern of increase in claudin-1 and HDAC-2 mRNA expression throughout all stages of colon cancer. Inhibition of claudin-1 expression by HDAC-2-specific small interfering RNA further supported the role of HDAC-2 in this regulation. Taken together, we report a novel post-transcriptional regulation of claudin-1 expression in colon cancer cells and further show a functional correlation between claudin-1 expression and TSA-mediated regulation of invasion. As HDAC inhibitors are considered to be promising anticancer drugs, these new findings will have implications in both laboratory and clinical settings.

Amphibian sex determination: segregation and linkage analysis using members of the tiger salamander species complex (Ambystoma mexicanum and A. t. tigrinum)

Little is known about the genetic basis of sex determination in vertebrates though considerable progress has been made in recent years. In this study, segregation analysis and linkage mapping were performed to localize an amphibian sex-determining locus (ambysex) in the tiger salamander (Ambystoma) genome. Segregation of sex phenotypes (male and female) among the second generation individuals of interspecific crosses (Ambystoma mexicanum x Ambystoma tigrinum tigrinum) was consistent with Mendelian expectations, although a slight female bias was observed. Individuals from these same crosses were typed for single-nucleotide polymorphisms distributed throughout the genome to identify molecular markers for ambysex. A marker (E24C3) was identified approximately 5.9 cM from ambysex. Linkage of E24C3 to ambysex was independently validated in a second, intraspecific cross (A. mexicanum). Interestingly, ambysex locates to the tip of one of the larger linkage groups of the Ambystoma meiotic map. Considering that this location does not show reduced recombination, we speculate that the ambysex locus may have arisen quite recently, within the last few million years. Localization of ambysex sets the stage for gene identification and provides important tools for studying the effect of sex in laboratory and natural populations of this model amphibian system.

Assessment of the mucosa of the indefinitely diverted ileo-anal pouch

OBJECTIVE

One surgical option to treat failure after restorative proctocolectomy (RPC) is indefinite diversion (ID) without excision of the pouch. The study aimed to assess the mucosal morphology of the pouch and ileoanal anastomosis (IAA) over time after ID with particular reference to inflammation, dysplasia and carcinoma.

METHOD

Patients with ID were identified from the hospital's Ileal Pouch Database. Individuals were invited by mail to attend for flexible pouchoscopy and biopsy from the ileal pouch and immediately distal to the IAA.

RESULTS

Of 1822 patients on the database, 28 had undergone ID. Of these, 20 patients (18 ulcerative colitis, one familial adenomatous polyposis, one pseudo-obstruction) of median age 42 (18-67) years took part. There were eight males. The median (range) intervals from diagnosis of primary disease, pouch surgery and ID to the time of study were 221 (63-410), 146 (31-314) and 44 (10-159) months respectively. One patient had dysplasia in the original resection specimen. Five patients developed type C changes in the pouch. Of these three were identified between RPC and ID, one developed between ID and the present assessment and one was identified for the first time at the present assessment. No case of dysplasia or cancer was found in any of the biopsies. Rectal mucosa was found in biopsies from the IAA in four patients (three stapled; one handsewn); this was inflamed in three patients.

CONCLUSION

At a median follow-up of 12 years after RPC and 3.6 years after indefinite diversion no instance of dysplasia or carcinoma in the ileal reservoir or distal to the IAA was found in any of the 20 patients having ID. Type C changes occurred at some time in five (25%) patients, indicating the importance of continued follow up.

Quality of life after indefinite diversion/pouch excision in ileal pouch failure patients

OBJECTIVE

Pouch failure occurs in up to 10% of patients over a 10-year period for a variety of reasons. One surgical option is pouch excision (PE) and form a permanent ileostomy. This is a major procedure with potential serious complications. An alternative is indefinite diversion (ID) of the pouch without excision. The aim of this study was to examine the quality of life and functional outcome in these two groups of patients.

METHOD

Ninety-seven patients were identified from the database to have either PE or ID. Fifty-three patients (17 men) responded; comprising 31 patients after PE and 22 patients with ID in a case-control study and completed the SF-36 general health survey and the Cleveland Clinic Foundation (CCF) functional outcomes questionnaire.

RESULTS

There was no significant difference in the domains of SF-36 between the two groups (P > 0.18). All patients with PE had an end ileostomy whereas most patients with ID had a loop ileostomy (18 loop vs 4 end). There was no difference in stoma related complications except for stoma retraction in ID (7%vs 47%; P = 0.003). There was no significant difference in urinary symptoms between PE and ID groups (weak stream 26%vs 14%; P = 0.49, nocturia 22%vs 4%; P = 0.12, urgency 22%vs 9%; P = 0.28, urinary incontinence 22%vs 14%; P = 0.72 respectively). There was no difference in sexually active patients (73%vs 94%; P = 0.11). Of the seven male PE patients, five (71%) could achieve an erection and four (57%) could maintain an erection, compared with all 10 male patients in the ID group (P = 0.151 and 0.05 respectively). Thirty-three per cent of patients with PE and 62% of patients with ID reported that they would have pouch surgery again if indicated (P = 0.052) and 58% of patients with PE and 81% of patients with ID reported that they would recommend pouch surgery to others (P = 0.129). No case of dysplasia was seen in 18 of 22 ID patients in whom histology was available.

CONCLUSION

Quality of life after PE or ID was no different and male sexual function was significantly better after ID. Retraction of the stoma was more common in this group.

Proteomics of the peroxisome

Genomes provide us with a blue print for the potential of a cell. However, the activity of a cell is expressed in its proteome. Full understanding of the complexity of cells demands a comprehensive view of the proteome; its interactions, activity states and organization. Comprehensive proteomic approaches applied to peroxisomes have yielded new insights into the organelle and its dynamic interplay with other cellular structures. As technologies and methodologies improve, proteomics hold the promise for new discoveries of peroxisome function and a full description of this dynamic organelle.

Social deprivation and outcomes in colorectal cancer

Background

The aim of this study was to examine the influence of social deprivation on postoperative mortality and length of stay in patients having surgery for colorectal cancer.

Methods

Data were extracted from the Association of Coloproctology of Great Britain and Ireland database of patients presenting between April 2001 and March 2002. The effect of social deprivation, measured by the Townsend score, on 30-day postoperative mortality and length of stay was evaluated by two-level hierarchical regression analysis.

Results

A total of 7290 (86·8 per cent) patients underwent surgery. Operative mortality was 6·7 per cent and median length of stay 11 days. Deprivation indices were significantly higher in patients with Dukes' ‘D’ cancers, undergoing emergency surgery and with higher American Society of Anesthesiologists (ASA) grades (P &lt; 0·005). Worsening deprivation was associated with higher operative mortality and longer stay (P = 0·014). For each unit increase in deprivation, there was 2·9 (95 per cent confidence interval 0·5 to 5·2) per cent increase in 30-day mortality. On multifactorial analysis, social deprivation was an independent predictor of length of stay, but its effect on operative mortality was explained by differences in ASA grade, operative urgency and Dukes' classification.

Conclusion

Social deprivation was an independent risk factor of postoperative length of stay and associated with higher postoperative mortality. These results have important implications for risk modelling of postoperative outcomes.

Histological examination of circular stapled ‘doughnuts’: Questionable routine practice?

BACKGROUND

Left-sided colonic resections are often anastomosed by the use of the circular stapling gun. Most surgeons routinely submit the resulting set of 'doughnuts' for histological examination.

AIM

The aim of this study is to question the need for this practice by providing our own experience of the impact of 'doughnut' submission on patient management.

PATIENTS AND METHODS

Patients who had undergone a stapled anastomosis for colorectal cancer resection (1998-2004) were identified from the department cancer database and clinical records and histopathological reports were reviewed for all cases.

RESULTS

From a consecutive series of 100 sets of doughnuts only two showed histological abnormality (inflammatory change and a metaplastic polyp). Three patients had local recurrence over the follow-up period: 12, 14 and 36 months after surgery. Histological review of the 'doughnuts' in these patients did not show any abnormality. None of the above findings had any influence on subsequent management.

CONCLUSION

Histological examination of the 'doughnuts' has a considerable impact in terms of time and resource use. This study has shown no benefit in performing routine histological examination of the 'doughnuts'.

Long-term results of abdominal salvage surgery following restorative proctocolectomy

BACKGROUND

This study evaluated outcomes of patients who underwent abdominal salvage ileal pouch redo surgery and identified factors associated with pouch failure following restorative proctocolectomy.

METHODS

Data on patients who underwent abdominal salvage surgery in a tertiary referral centre between 1985 and 2003 were collected. Outcomes studied included failure of salvage and bowel function of patients with an intact intestine.

RESULTS

One hundred and twelve patients underwent 117 pouch salvage procedures for ulcerative colitis (86), indeterminate colitis/ulcerative colitis (eight), indeterminate colitis/Crohn's disease (three), familial adenomatous polyposis (ten) and other conditions (five). The most common indications for pouch salvage were intra-abdominal sepsis (45 patients), anastomotic stricture (13) and retained rectal stump (35). Median follow-up was 46 (range 1-147) months. Twenty-four patients (21.4 per cent) experienced pouch failure, the incidence of which increased with time. The pouch failed in all patients with Crohn's disease. Successful salvage at 5 years was significantly associated with non-septic (85 per cent) rather than septic (61 per cent) indications (P = 0.016). Frequency of night-time defaecation and faecal urgency improved after salvage surgery (P = 0.036 and P = 0.016 respectively at 5-year follow-up; n = 32).

CONCLUSION

Abdominal salvage surgery was associated with a failure rate of 21.4 per cent. A successful outcome was less likely when the procedure was carried out for septic compared with non-septic indications. The rate of pouch failure increased with length of follow-up.

Anabolic effects of acellular bone marrow, platelet rich plasma, and serum on equine suspensory ligament fibroblasts in vitro

The purpose of this study was to investigate the response of suspensory ligament fibroblasts (SLF) to in vitro stimulation using acellular bone marrow (ABM), platelet rich plasma (in vitro PRP), and serum as potential treatment modalities for suspensory desmitis. Blood, bone marrow, and suspensory ligaments were collected from five horses. SLF were harvested, grown until confluent, and stimulated with various concentrations of ABM, PRP, equine serum, foetal bovine serum, and medium (control). The responses to the treatments were assessed using a combination of radio-labeling for total protein synthesis and an ELISA for quantification of Cartilage Oligomeric Matrix Protein (COMP) production. Addition of all of the samples resulted in significant increases in COMP and total protein synthesis over controls (P<0.001). ABM caused the greatest increase in both COMP and total protein synthesis by the SLF. Equine ABM, PRP, and serum contain anabolic factors that promote matrix synthesis by SLF in vitro, with ABM having the greatest effect. Application of bone marrow to injured ligaments may enhance healing by providing anabolic factors, other than or in addition to mesenchymal stem cells, which stimulate matrix production.