Open versus Closed technique for administration of heated intraperitoneal chemotherapy (HIPEC): Morbidity and Mortality outcomes from a high-volume centre

BACKGROUND AND AIMS

Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) is an established treatment in selected patients with peritoneal metastases, delivered in the UK in specialist centres. HIPEC can be administered via the open coliseum technique as first described by Sugarbaker (O-HIPEC) or using a closed technique (C-HIPEC). Data comparing the safety and outcomes of these different approaches is limited. This study aims to compare morbidity and mortality rates of O-HIPEC and C-HIPEC following CRS for peritoneal metastases from colorectal cancer and appendiceal tumours.

METHODS

Consecutive patients undergoing CRS with open (05/2019-04/2020) and closed (05/2020-04/2021) HIPEC were identified from a prospectively maintained database. Baseline data including primary pathology, HIPEC agent and major operative procedures were analysed using Chi-squared and Fishers exact tests to ensure comparability of groups. Primary outcomes were 30- and 60-day postoperative mortality and morbidity (Common Terminology Criteria for Adverse Events, CTCAE). Secondary outcomes were length of critical care and overall hospital stay. In addition, morbidity and mortality were compared between HIPEC agents (mitomycin and oxaliplatin/5-fluorouracil).

RESULTS

99 patients (39.3%) and 153 patients (60.7%) underwent O-HIPEC, C-HIPEC respectively. Groups were well matched for baseline demographics, pathology, and HIPEC agent. In the O-HIPEC and C-HIPEC groups respectively, the incidence of 60-day complications (CTCAE 1-4) was 40.4% vs 39.3% (chi squared 0.94) and severe complications (CTCAE 3-4) 14% vs 13% (Fisher's exact p = 1) There was no perioperative mortality but one death in each group within the follow up period. There was no difference in morbidity or mortality between those receiving mitomycin or oxaliplatin.

CONCLUSION

Closed administration of HIPEC is safe with no difference in post-operative morbidity or mortality compared to open HIPEC administration. Differences in longer term oncological outcomes including overall survival and disease-free survival between open and closed HIPEC techniques are yet to be determined.

Evaluating the potential utility of three-dimensional printed models in preoperative planning and patient consent in gastrointestinal cancer surgery

INTRODUCTION

The Future of Surgery report from the Royal College of Surgeons of England acknowledges the important role that three-dimensional imaging will play in support of personalised surgical interventions. One component of this is preoperative planning. We investigated surgeons' and patients' perceptions of this evolving technology.

MATERIALS AND METHODS

Ethical approval was obtained. From a normal computed tomography scan, three-dimensional models of the stomach, pancreas and rectum were rendered and printed on an Ultimaker™ three-dimensional printer. Semi-structured interviews were performed with surgeons and patients to explore perceived model effectiveness and utility. Likert scales were used to grade responses (1 = strongly disagree; 10 = strongly agree) and qualitative responses recorded.

RESULTS

A total of 26 surgeons (9 rectal, 9 oesophagogastric, 8 pancreatic) and 30 patients (median age 62 years, interquartile range, IQR, 68-72 years; 57% male) were recruited. Median surgeon scores were effectiveness for preoperative planning, 6 (IQR 3-7), authenticity, 5 (IQR 3-6), likability, 6 (IQR 4-7), promoting learning, 7 (IQR 5-8), utility, 6 (IQR 5-7) and helping patients, 7 (IQR 5-8). Median patient scores were usefulness to the surgeon, 8 (IQR 7-9), authenticity, 8 (IQR 6-8), likability, 8 (IQR 7-8), helping understanding of condition, 8 (IQR 8-9), helping understanding of surgery, 8 (IQR 7-9) and feeling uncomfortable, 1 (IQR 1-4). Median overall decisional conflict score (0 = no; 100 = high) was 22 (IQR 19-28) and decision effectiveness was 25 (IQR 19-30).

DISCUSSION

Overall, patients and surgeons considered that three-dimensional printed models were effective and had potential utility in education and, to a lesser extent, preoperative planning. Patient decisional conflict and effectiveness scores were weighted towards certainty in decision making but had room for improvement, which three-dimensional models may help to facilitate.

O11: MYOFERLIN: A NOVEL BIOMARKER OF RADIOSENSITIVITY IN LOCALLY ADVANCED RECTAL CANCER

Introduction

Our proteomic data has validated that high levels of the protein myoferlin confers poorer response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer. Myoferlin plays a role in membrane repair and VEGF signal transduction, and is associated with worse prognosis in numerous other epithelial cancers. We aim to assess the impact of myoferlin on the radiosensitivity of rectal cancer.

Method

Clonogenic assays were performed using immortalised colorectal cancer cells (HCT116,HT29,LIM,MDST8) to assess survival at escalating radiation doses following knockdown with myoferlin siRNA or a small molecular inhibitor(WJ460). 3D models (spheroids) were used to examine the effect of WJ460 on tumour growth.

Result

Quantification of myoferlin using immunoblotting demonstrated that MDST8 and LIM were higher expressors than HCT116 and HT29. Higher levels correlated with increasing radio-resistance as calculated by colony formation efficiency (CFE). Using clonogenic assays, cells treated with myoferlin siRNA or WJ460 demonstrated increased radiosensitivity compared to controls across all radiation doses, most significantly at 4Gy. Treatment of spheroids with WJ460 significantly reduced growth compared to controls at all radiation doses (p<0.05), with WJ460 limiting growth considerably more than treatment with the current gold standard 5-FU. HCT116 spheroid volume day 15; WJ460 4.96um3,5-FU 6.74um3,DMSO 24.9um3.

Conclusion

Inhibition of myoferlin is associated with increased radiosensitivity of colorectal cancer cells, and treatment with a small molecular inhibitor significantly reduces growth in spheroid models. Further work is required further validate its potential use as a biomarker in locally advanced rectal cancer.

Take-home message

We have found that myoferlin is a protein associated with poor response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer. Manipulation of this protein sensitises the cancer cells to radiotherapy.

O48: MYOFERLIN: A NOVEL PREDICTIVE BIOMARKER AND THERAPEUTIC TARGET IN ADVANCED COLORECTAL CANCER

Introduction

Myoferlin is a protein involved in cell proliferation, migration and angiogenesis, which are essential in tumour metastasis. Its expression correlates with a poorer prognosis in various epithelial cancers, but has yet to be associated with survival in colorectal cancer. We aim to investigate myoferlin's role in cell migration, and the development of metastases in our patients with rectal cancer.

Method

Tissue Microarrays (TMAs) of matched tumour and lymph node samples from 111 patients with rectal cancer were stained for myoferlin. Expression profiles were examined and correlated with clinical outcomes. Wound healing assays were used to assess the rate of migration in immortalised colorectal cells (HCT116, HT29) following myoferlin knockdown with siRNA.

Result

Our TMAs demonstrated that high myoferlin expression in rectal tumour samples was associated with metastatic spread to local lymph nodes (p<0.05). Positive lymph nodes had significantly higher levels of myoferlin than non-involved lymph nodes (p<0.001). The positive predictive value (PPV) of a highly expressing lymph node containing metastatic spread was 100%, negative predictive value (NPV) 88.41%, 95% CI [80.81, 93.24]. Wound healing assays demonstrated a decreased ability of cells to migrate following myoferlin knockdown with siRNA, compared to controls (p<0.05).

Conclusion

Our results demonstrate that high myoferlin expression is associated with metastatic spread to local lymph nodes, and increased migration and proliferation of cells. It is a predictor of poor clinical outcomes, and therefore warrants further investigation as a potential therapeutic target in both locally advanced and metastatic rectal cancer.

Take-home message

We have demonstrated that the protein myoferlin is associated with metastatic spread of rectal cancer to local lymph nodes. Therefore it is a potential predictive biomarker and therapeutic target in advanced rectal cancer.

Hartmann's procedure versus intersphincteric abdominoperineal excision (HiP Study): a multicentre prospective cohort study

AIM

In patients with low rectal cancer it is occasionally necessary to avoid a low coloanal anastomosis due to patient frailty or poor function. In such situations there are two alternative approaches: Hartmann's procedure (HP) or intersphincteric abdominoperineal excision (IAPE). There are few data to guide surgeons as to which of these two procedures is the safest. The aim of this study was to determine the surgical complication rates associated with each procedure.

METHOD

This was a multicentre, nonrandomized prospective cohort study of patients undergoing either HP or IAPE. The primary objective was to determine surgical complication rates. Secondary objectives included length of stay, time to adjuvant therapy and quality of life at 90 days.

RESULTS

One hundred and seventy nine patients were recruited between April 2016 and June 2019; approximately two thirds of patients underwent HP and one third IAPE. The overall complication rate was high in both groups (54% for the HP group and 52% for the IAPE group). Surgery-specific complication rates were also high, but not significantly different: 43% for HP and 48% for IAPE. The pelvic abscess rate in HP was 11% and was significantly higher in patients with a palpable staple line (15% vs 2%). There was a higher incidence of serious medical complications following IAPE (16% vs 5%), along with a reduction in 90-day quality of life scores.

CONCLUSION

This is the largest prospective study to compare HP and IAPE in patients undergoing rectal cancer surgery where primary anastomosis is not deemed appropriate. With similar complication rates, these data support the ongoing use of either HP or IAPE in this patient group.

Determination of Lead in Wine by Graphite Furnace Atomic Absorption Spectrophotometry: Interlaboratory Study

An interlaboratory study of a graphite furnace atomic absorption spectrophotometry (GFAAS) method for the determination of lead in wine was conducted. Seventeen laboratories from France, United States, and the United Kingdom, using a variety of GFAAS instruments, took part in the study. The method incorporated a novel matrix-matching procedure to minimize matrix effects between standards and samples. Six wine test materials were prepared and sent to participants as 12 blind duplicate or split level samples. There was good agreement between results obtained from participants and target values (24–279 μg/L) obtained with an inductively coupled plasma-mass spectrometry method. The precision of the GFAAS method was well within the range predicted by the Horwitz equation for the 6 test materials analyzed. Repeatability standard deviations ranged from 3 to 17%. Reproducibility standard deviations were in the range of 10 to 30%. The method is recommended for use for official purposes.

Transarterial angioembolization versus surgery after failed endoscopic therapy for non-variceal upper gastrointestinal bleeding

BACKGROUND AND OBJECTIVE

To compare the outcome of transarterial angioembolization (TAE) and surgery with endoscopically unmanageable non-variceal hemorrhage of the upper gastrointestinal tract.

MATERIALS AND METHODS

A case note review of all patients treated for non-variceal upper gastrointestinal bleeding from January 2006 till January 2012 was performed.

RESULTS

Fifty-four of 667 patients with non-variceal bleeding did not respond to endoscopic treatment. Nine of the 54 patients had incomplete data, leaving 45 patients in the study; 24 had angiography and another 21 had surgery. The two groups were broadly similar in terms of relevant clinical variables. Nineteen of 24 having angiography had embolisation. Re-bleeding recurred in 8 patients (33%) in the TAE group and 6 patients (28.6%) in the surgery group (p = 0.28). There was no statistically significant difference in post procedural complications (81% vs 62.5%, p = 0.17), 30-day mortality (33% vs 29.1%, p = 0.17 ) units of blood transfused (12.24 vs 8.92, p = 0.177) and mean hospital stay (30.7 vs 22.9 days, p = 0.281) observed in patients undergoing surgery as compared to TAE.

CONCLUSIONS

TAE and surgery have similar outcomes in patients with endoscopically unmanageable non-variceal upper gastrointestinal haemorrhage.

MUC13 protects colorectal cancer cells from death by activating the NF-κB pathway and is a potential therapeutic target

MUC13 is a transmembrane mucin glycoprotein that is over produced by many cancers, although its functions are not fully understood. Nuclear factor-κB (NF-κB) is a key transcription factor promoting cancer cell survival, but therapeutically targeting this pathway has proved difficult because NF-κB has pleiotropic functions. Here, we report that MUC13 prevents colorectal cancer cell death by promoting two distinct pathways of NF-kB activation, consequently upregulating BCL-X_L. MUC13 promoted tumor necrosis factor (TNF)-induced NF-κB activation by interacting with TNFR1 and the E3 ligase, cIAP1, to increase ubiquitination of RIPK1. MUC13 also promoted genotoxin-induced NF-κB activation by increasing phosphorylation of ATM and SUMOylation of NF-κB essential modulator. Moreover, elevated expression of cytoplasmic MUC13 and NF-κB correlated with colorectal cancer progression and metastases. Our demonstration that MUC13 enhances NF-κB signaling in response to both TNF and DNA-damaging agents provides a new molecular target for specific inhibition of NF-κB activation. As proof of principle, silencing MUC13 sensitized colorectal cancer cells to killing by cytotoxic drugs and inflammatory signals and abolished chemotherapy-induced enrichment of CD133⁺ CD44⁺ cancer stem cells, slowed xenograft growth in mice, and synergized with 5-fluourouracil to induce tumor regression. Therefore, these data indicate that combining chemotherapy and MUC13 antagonism could improve the treatment of metastatic cancers.

Persistent Mullerian Duct Syndrome: an interesting case report

Transverse testicular ectopia is an uncommon disorder of testicular ectopia. Nearly thirty percent of the cases is associated with Persistent mullerian duct syndrome which is characterized by karyotypically normal males with retained mullerian derivatives. Understanding the natural process of the condition and the association with malignant potential will allow for a better understanding of the optimal surgical approach. This is a case report of young male presented a left sided inguinal hernia in which the sac contained both testes and uterus. The literature review of the syndrome will be discussed.

California Breast Cancer Prevention Initiatives: Setting a research agenda for prevention

The environment is an underutilized pathway to breast cancer prevention. Current research approaches and funding streams related to breast cancer and the environment are unequal to the task at hand. We undertook the California Breast Cancer Prevention Initiatives, a four-year comprehensive effort to set a research agenda related to breast cancer, the environment, disparities and prevention. We identified 20 topics for Concept Proposals reflecting a life-course approach and the complex etiology of breast cancer; considering the environment as chemical, physical and socially constructed exposures that are experienced concurrently: at home, in the community and at work; and addressing how we should be modifying the world around us to promote a less carcinogenic environment. Redirecting breast cancer research toward prevention-oriented discovery could significantly reduce the incidence and associated disparities of the disease among future generations.

Hepatic activation of irinotecan predicts tumour response in patients with colorectal liver metastases treated with DEBIRI: exploratory findings from a phase II study

PURPOSE

The response of colorectal liver metastases to the cytotoxic agent irinotecan varies widely. Attempts to correlate tumour metabolism with response have been mixed. This study investigated the hepatic metabolism of irinotecan as a potential predictor of tumour response to irinotecan-eluting beads (DEBIRI).

METHODS

Ten patients with colorectal liver metastases were treated with 200 mg irinotecan (as DEBIRI) as part of the PARAGON II study. Hepatic expression of key metabolising enzymes was measured using mass spectrometry-based proteomics. Serum drug concentrations and hepatic irinotecan metabolism were characterised and correlated with tumour response.

RESULTS

Serum concentrations of irinotecan metabolites did not correlate with hepatic metabolism or pathological response. There was a strong correlation between hepatic CES-2 expression and activation of irinotecan (r (2) = 0.96, p < 0.001). Patients with a UGT1A1*28 6/7 SNP showed no difference in drug metabolism or pathological response. Hepatic CES-2 mediated activation of irinotecan clearly correlated with tumour replacement by fibrosis (r (2) = 0.54, p = 0.01).

CONCLUSION

This study provides the first evidence that hepatic activation of irinotecan predicts tumour response. Delivery of liver-targeted irinotecan to normal liver tissue rather than tumour may be a more rational approach to maximise response.

Visceral hypersensitivity in symptomatic diverticular disease and the role of neuropeptides and low grade inflammation

BACKGROUND

  Recurrent abdominal pain is reported by a third of patients with diverticulosis, particularly those with previous episodes of acute diverticulitis. The current understanding of the etiology of this pain is poor. Our aim was to assess visceral sensitivity in patients with diverticular disease and its association with markers of previous inflammation and neuropeptides.

METHODS

  Patients with asymptomatic and symptomatic diverticular disease underwent a flexible sigmoidoscopy and biopsy followed 5-10 days later by visceral sensitivity testing with barostat-mediated rectal distension. Inflammation was assessed by staining of serotonin (5HT) and CD3 positive cells. mRNA levels of tumor necrosis factor alpha (TNF α) and interleukin-6 (IL-6) were quantitated using RT-PCR. Neuropeptide expression was assessed from percentage area staining with substance P (SP) and mRNA levels of the neurokinin 1 & 2 receptors (NK1 & NK2), and galanin 1 receptor (GALR1).

KEY RESULTS

  Thirteen asymptomatic and 12 symptomatic patients were recruited. The symptomatic patients had a lower first reported threshold to pain (28.4 mmHg i.q.r 25.0-36.0) than the asymptomatic patients (47 mmHg i.q.r 36.0-52.5, P < 0.001). Symptomatic patients had a higher median overall pain rating for the stimuli than the asymptomatic patients (P < 0.02). Symptomatic patients had greater median relative expression of NK1 and TNF alpha mRNA compared with asymptomatic patients. There was a significant correlation between barostat VAS pain scores and NK 1 expression (Figure 4, r(2) 0.54, P < 0.02).

CONCLUSIONS & INFERENCES

  Patients with symptomatic diverticular disease exhibit visceral hypersensitivity, and this may be mediated by ongoing low grade inflammation and upregulation of tachykinins.

The low contact stress patellofemoral replacement

The low contact stress patellofemoral replacement consists of a trochlear component and a modular patellar component which has a metal-backed mobile polyethylene bearing. We present the early results of the use of this prosthesis for established isolated patellofemoral arthritis in 51 consecutive patellofemoral replacements in 35 patients. The mean follow-up was 25 months (5 to 60). The estimated survival rate at three years was 63% (95% confidence interval 47 to 80) with revision as the endpoint and 46% (95% confidence interval 30 to 63) with revision and ongoing moderate or severe pain as the endpoint.

The early results of the use of the low contact stress patellofemoral replacement are disappointing with a high rate of revision. We cannot therefore recommend its use.

HLA class I and class II polymorphisms in Saudi patients with myasthenia gravis

Myasthenia gravis (MG) is a rare autoimmune disease of the neuromuscular junction. MG has been shown to be associated with many HLA antigens in different populations. Here we have analysed the frequency of HLA-A, B, DR and DQ in a group of Saudi MG patients and compared their results to a group of healthy controls. MG in Saudi patients is found to be associated with HLA-A*23, B*08, B*18, DRB1*16 and DRB1*13. The strongest association was with HLA-B*08, which was associated with young age at onset and female gender. Our results are in line with other published results from around the world and warrant fine mapping of the area using microsatellite to map the disease gene.

Pronase-free B-cell flow-cytometry crossmatch

Detection of anti-class II antibodies by panel response assay (PRA) and flow cross-match techniques carries an important value in terms of graft function. Even low levels of pre-formed alloantibodies to HLA class II antigens represent a risk of rejection. We present here a method for blocking non-specific flow crossmatch reactions using pooled, heat-inactivated rabbit serum. This method shows very low background and minimal non-specific reactions. In addition, it avoids the use pronase enzyme that can non-specifically digest different cell surface proteins.

Mucins in the mucosal barrier to infection

The mucosal tissues of the gastrointestinal, respiratory, reproductive, and urinary tracts, and the surface of the eye present an enormous surface area to the exterior environment. All of these tissues are covered with resident microbial flora, which vary considerably in composition and complexity. Mucosal tissues represent the site of infection or route of access for the majority of viruses, bacteria, yeast, protozoa, and multicellular parasites that cause human disease. Mucin glycoproteins are secreted in large quantities by mucosal epithelia, and cell surface mucins are a prominent feature of the apical glycocalyx of all mucosal epithelia. In this review, we highlight the central role played by mucins in accommodating the resident commensal flora and limiting infectious disease, interplay between underlying innate and adaptive immunity and mucins, and the strategies used by successful mucosal pathogens to subvert or avoid the mucin barrier, with a particular focus on bacteria.

Lung cancer in Teesside (UK) and Varese (Italy): a comparison of management and survival

BACKGROUND

The survival of lung cancer patients in the UK is lower than in other similar European countries. The reasons for this are unclear.

METHODS

Two areas were selected with a similar incidence of lung cancer: Teesside in Northern England and Varese in Northern Italy. Data were collected prospectively on all new cases of lung cancer diagnosed in the year 2000. Comparisons were made of basic demographic characteristics, management, and survival.

RESULTS

There were 268 cases of lung cancer in Teesside and 243 in Varese. Patients in Teesside were older (p<0.05), were more likely to have smoked (p<0.001), had a higher occupational risk (p<0.001), higher co-morbidity (p<0.05), and poorer performance status (p<0.001). Fewer patients in Teesside presented as an incidental finding (p<0.001) and the histological confirmation rate was lower than in Varese (p<0.01). In Teesside there were more large cell carcinomas (p<0.001), more small cell carcinomas (p<0.05), and fewer early stage non-small cell lung cancers (p<0.05). The resection rate was lower in Teesside (7% v 24%; p<0.01) and more patients received no specific anti-cancer treatment (50% v 25%; p<0.001). Overall 3 year survival was lower in Teesside (7% v 14%; p<0.001). Surgical resection was the strongest multivariate survival predictor in Varese (HR = 0.46) and Teesside (HR = 0.31). Co-morbidity in Teesside resulted in a significantly lower resection rate (p<0.001).

CONCLUSIONS

Patients with lung cancer in Teesside presented at a later stage, with more aggressive types of tumour, and had higher co-morbidity than patients in Varese. As a result, the resection rate was significantly lower and survival was worse.

Helicobacter pylori vaccines spiral into the new millennium

This article reviews the current situation regarding research towards an effective human vaccine against Helicobacter pylori, with particular emphasis on developments in the new millennium. The mechanism(s) by which immunisation of mice can affect helicobacter colonisation of mice remains a mystery, but may be related to immune mediated environmental changes. In particular, it is proposed that severe gastritis and T-cell mediated changes in mucin production can significantly impact upon H. pylori colonisation. Despite the potential influence of environmental factors, significant progress towards a truly effective vaccine may depend upon the induction of specific immune targeting of this pathogen. This would probably be best achieved by the generation of an appropriate antibody response, something which has not yet been accomplished. An overview of previous and current H. pylori vaccine clinical trials is also presented.

Iron deficiency associated with higher blood lead in children living in contaminated environments

The evidence that iron deficiency increases lead child exposure is based primarily on animal data and limited human studies, and some of this evidence is contradictory. No studies of iron status and blood lead levels in children have accounted for environmental lead contamination and, therefore, the source of their exposure. Thus, no studies have directly determined whether iron deficiency modifies the relationship of environmental lead and blood lead. In this study, we compared blood lead levels of iron-deficient and iron-replete children living in low, medium, or highly contaminated environments. Measurements of lead in paint, soil, dust, and blood, age of housing, and iron status were collected from 319 children ages 1-5. We developed two lead exposure factors to summarize the correlated exposure variables: Factor 1 summarized all environmental measures, and Factor 2 was weighted for lead loading of house dust. The geometric mean blood lead level was 4.9 microg/dL; 14% exceeded 10 microg/dL. Many of the children were iron deficient (24% with ferritin < 12 ng/dL). Seventeen percent of soil leads exceeded 500 microg/g, and 23% and 63% of interior and exterior paint samples exceeded 5,000 microg/g. The unadjusted geometric mean blood lead level for iron-deficient children was higher by 1 microg/dL; this difference was greater (1.8 microg/dL) after excluding Asians. Blood lead levels were higher for iron-deficient children for each tertile of exposure as estimated by Factors 1 and 2 for non-Asian children. Elevated blood lead among iron-deficient children persisted after adjusting for potential confounders by multivariate regression; the largest difference in blood lead levels between iron-deficient and -replete children, approximately 3 microg/dL, was among those living in the most contaminated environments. Asian children had a paradoxical association of sufficient iron status and higher blood lead level, which warrants further investigation. Improving iron status, along with reducing exposures, may help reduce blood lead levels among most children, especially those living in the most contaminated environments.

Post-immunisation gastritis and Helicobacter infection in the mouse: a long term study

BACKGROUND AND AIMS

Helicobacter pylori is a major cause of peptic ulcers and gastric cancer. Vaccine development is progressing but there is concern that immunisation may exacerbate Helicobacter induced gastritis: prophylactic immunisation followed by challenge with H felis or H pylori can induce a more severe gastritis in mice than seen with infection alone. The aim of this study was to investigate the relationship between immunity to Helicobacter infection and post-immunisation gastritis.

METHODS

(1) C57BL/6 mice were prophylactically immunised before challenge with either H felis or H pylori. Histopathology and colonisation were assessed one month post-challenge. (2) C57BL/6 mice were prophylactically immunised against H felis infection and gastritis assessed up to 18 months post-challenge.

RESULTS

Prophylactic immunisation induced a reduction in bacterial colonisation following H felis challenge which was associated with increased severity of active gastritis with neutrophil infiltration and atrophy. However, immunised mice challenged with H pylori SS1 had little evidence of pathology. Long term follow up showed that post-immunisation gastritis was evident at three months. However, from six months onwards, although immunised/challenged mice still developed gastritis, there was no significant difference between inflammation in these mice and infected controls. Post-immunisation gastritis was not associated with the serum antibody response. Immunisation prevented the formation of secondary lymphoid aggregates in the gastric tissue.

CONCLUSION

The H felis mouse model of post-immunisation gastritis is the most extreme example of this type of pathology. We have shown in this model that post-immunisation gastritis is a transient event which does not produce long term exacerbation of pathology.

Helicobacter-induced expression of Bcl-X(L) in B lymphocytes in the mouse model: a possible step in the development of gastric mucosa-associated lymphoid tissue (MALT) lymphoma

Primary gastric mucosa-associated lymphoid tissue (MALT) lymphoma may develop from chronic infection with Helicobacter sp. in the mouse model. The mechanisms of pathogenesis remain unclear. Regulation of B-cell proliferation and death are important features to investigate. Proteins encoded by bcl-2 family genes, e.g., Bcl-X(L), regulate apoptosis; and alterations in the expression of these genes can contribute to the development of cancer. Our aim was to determine the role of Bcl-X(L) in B lymphocytes in the development of gastric MALT lymphoma associated with Helicobacter infection using the BALB/c mouse model. We analyzed 37 animals with Helicobacter-associated MALT (n = 25), low-grade MALT lymphoma (n = 10) and high-grade lymphoma (n = 2), investigating the in vivo distribution of Bcl-X(L) in B cells/B-lymphoma cells using immunohistochemical analysis. In vitro cultivation of B cells/B-lymphoma cells was employed to perform RT-PCR analysis of Bcl-X(L) mRNA expression after cell stimulation with Helicobacter antigen. We found significant Bcl-X(L) protein expression in B lymphocytes within MALT and low-grade MALT lymphoma, whereas there was no and minimal expression, respectively, of Bcl-X(L) in the 2 high-grade MALT lymphoma cases. Expression of bcl-X(L) mRNA in B lymphocytes was up-regulated in vitro upon Helicobacter-antigen stimulation and associated with prolonged cell survival. These findings support the hypothesis that Bcl-X(L) plays a role in the pathogenesis of B-cell MALT lymphoma by providing cell-survival signals and by triggering the acquisition of MALT.

Progress in vaccination against Helicobacter pylori

This review discusses recent progress in the development of a vaccine against Helicobacter pylori. This progress includes demonstration that: effective immunisation is independent of antibodies but dependent upon CD4+ T helper cells, although their role remains unknown; the immunisation regime can be improved to increase efficacy; successful immunisation against H. pylori is possible using a live vector; a strain of H. pylori suitable for experimental infection of humans has been developed. Important issues that remain to be addressed include incomplete protection, non-availability of suitable mucosal adjuvants and post-immunisation gastritis. Significantly, commercial development of products for clinical trial is underway.

Helicobacter pylori vaccines and mechanisms of effective immunity: is mucus the key?

In this theoretical article, the hypothesis is proposed that immunization against gastric helicobacter infection is mediated by CD4+ T-cell induced changes in mucus production. Vaccine development for the gastric pathogen Helicobacter pylori has encountered several problems. Resolving these problems is impeded by our lack of understanding of the mechanisms by which the immune response influences bacterial colonization. Protective immunity requires CD4+ T cells, but the majority of helicobacters are located in the mucus of the gastric lumen, away from the epithelial surface. Evidence suggests that this mechanism functions independently of antibodies, so how this is achieved is unknown. Clues to this mechanism may be provided by immune clearance of nematode infection. Similar to H. pylori, expulsion of the intestinal nematode, Nippostrongylus brasiliensis, in rodents is mediated by CD4+ T-cell changes in the numbers of goblet cells and the type of mucins secreted into the gut. Immune-mediated changes in secretion of gastric mucins could similarly be responsible for the reductions in helicobacter colonization seen in immunized animals. Helicobacter pylori are highly motile bacteria that have evolved to inhabit their specialized niche. Alterations in their mucus environment could influence their motility, such that the bacteria cannot remain efficiently within the mucus and are flushed away.

A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization

Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the 'iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction.

Review article: Helicobacter pylori vaccines-the current status

In this review, we take a look at the current status in the development of a vaccine against the human pathogenic bacterium, Helicobacter pylori, a major aetiological factor in peptic ulcer disease and gastric adenocarcinoma. Various animal models are now in use from mice infected with H. pylori, through gnotobiotic pigs and primates to ferrets naturally infected with their own Helicobacter, H. mustelae. A significant problem remains the requirement for a suitable mucosal adjuvant. Detoxification or the use of low doses of adjuvants already available may provide a solution and new immune stimulating compounds have been tested with some success. New approaches include the delivery of Helicobacter antigens by DNA immunization, microparticles or live vectors such as attenuated salmonella and the examination of alternative routes of vaccine administration. The phenomenon of post-immunization gastritis and improvements in vaccine efficacy are also discussed. A major area of interest is the mechanism by which immunization actually influences Helicobacter colonization. This remains a mystery: antibodies appear to be unimportant whereas CD4+ T-cells essential. Finally, a viewpoint is given on whom should be immunized when a final vaccine becomes available.

Dominant nonresponsiveness to Helicobacter pylori infection is associated with production of interleukin 10 but not gamma interferon

Helicobacter pylori-induced gastritis is an essential precursor lesion for the development of peptic ulcers or gastric adenocarcinoma. We demonstrate that nonresponsiveness to H. pylori SS1 infection is dominantly inherited in mice. F(1) hybrid crosses between a nonresponder mouse and three responder strains all possessed the nonresponder phenotype. Secretion of interleukin-10 but not gamma interferon was associated with nonresponsiveness to infection.

Combined lesions of hippocampus and subiculum Do not produce deficits in a nonspatial social olfactory memory task

Rats transmit information to each other about which foods are safe to eat. If a rat smells a food odor on the breath of another rat, it is subsequently more likely to eat that food than an alternative. Work by Galef et al. (1988) has shown that the observer rat forms an association between two olfactory stimuli on the breath of the demonstrator rat that has eaten the food, the food odor and carbon disulphide, which is normally present in the rat breath. Bunsey and Eichenbaum (1995) claimed that the hippocampus/subicular region is required for the long-term retention of this nonspatial form of associative memory on the basis that combined lesions of the hippocampus and subiculum produced a deficit, but lesions of either structure alone did not. We report here a failure to repeat this finding. Rats with either combined lesions of the hippocampus and subiculum or with amygdala lesions were tested on their ability to remember this association either immediately (testing short-term memory) or after a 24 hr delay (testing long-term memory). Neither lesion group exhibited significant memory deficits on this nonspatial associative task at either test interval. In contrast, a deficit was observed on a spatial memory task (forced-choice alternation t-maze) for animals with combined lesions of the hippocampus and subiculum. These results contradict the findings of Bunsey and Eichenbaum (1995) and support the idea that the hippocampus/subicular region is not required for this nonspatial associative memory.

Further development of the Helicobacter pylori mouse vaccination model

Immunisation against Helicobacter infection in mouse models has thus far produced neither complete protection against the bacteria, nor a complete prevention of the associated gastritis. This study aimed firstly to compare the sensitivities of the various methods used to assess H. pylori infection in the mouse model, and secondly to develop the experimental design to induce a more effective immunity, aimed at further reducing bacterial burden in the gastric tissue. Various mouse strains were prophylactically immunised with whole bacterial sonicate and cholera toxin before challenge with H. pylori-SS1. The relative sensitivities of the urease assay, histological assessment and the colony forming assay to detect levels of H. pylori colonisation were compared. Comparisons of different antigen doses and different timecourses of immunisation were performed. The colony forming assay was found to be far more sensitive than either the urease assay or histological assessment for determining the protective efficacies of immunisation. Mice which had 10(5) H. pylori per gram of stomach by colony assay were negative by histology and urease. Lower doses of whole cell sonicate were more protective than high doses and more effective immunisation was achieved by leaving at least 3 weeks between immunisation instead of weekly immunisations. In conclusion, for assessment of H. pylori colonisation in the mouse model, the colony forming assay should be used. The experimental protocol for immunisation has been altered to produce a significant improvement in protection. However, full protection has still not yet been achieved and more work is still required.

Therapeutic immunization against Helicobacter pylori infection in the absence of antibodies

Helicobacter pylori is an important human pathogen. Prophylactic immunization with bacterial antigen plus an adjuvant protects mice against challenge with live H. pylori. Surprisingly, it was found that immunizations of mice already infected with Helicobacter also influenced bacterial colonization. This concept of therapeutic immunization is a novel phenomenon. Because H. pylori lives in the lumen of the stomach, it was initially hypothesized that the protective mechanism would involve induction of secretory IgA. However, work with knockout mice has demonstrated that prophylactic immunization is equally effective in mice deficient in IgA and even in microMT mice lacking B lymphocytes. Currently nothing is known about therapeutic vaccination and the effect of immunizing a host with an ongoing ineffective immune response. To address this, we infected B-cell deficient, microMT mice with H. pylori and therapeutically immunized them four times in 3 weeks with bacterial sonicate and cholera toxin adjuvant. These immunizations significantly reduced colonization by H. pylori. The antibody- negative status of the microMT mice was confirmed by ELISA. Thus, therapeutic immunization stimulates an immune response, which reduces H. pylori infection via a mechanism that is antibody independent. How this is achieved remains to be determined, but may well involve a novel immune mechanism.

Therapeutic immunization against Helicobacter pylori infection in the absence of antibodies

Helicobacter pylori is an important human pathogen. Prophylactic immunization with bacterial antigen plus an adjuvant protects mice against challenge with live H. pylori. Surprisingly, it was found that immunizations of mice already infected with Helicobacter also influenced bacterial colonization. This concept of therapeutic immunization is a novel phenomenon. Because H. pylori lives in the lumen of the stomach, it was initially hypothesized that the protective mechanism would involve induction of secretory IgA. However, work with knockout mice has demonstrated that prophylactic immunization is equally effective in mice deficient in IgA and even in microMT mice lacking B lymphocytes. Currently nothing is known about therapeutic vaccination and the effect of immunizing a host with an ongoing ineffective immune response. To address this, we infected B-cell deficient, microMT mice with H. pylori and therapeutically immunized them four times in 3 weeks with bacterial sonicate and cholera toxin adjuvant. These immunizations significantly reduced colonization by H. pylori. The antibody- negative status of the microMT mice was confirmed by ELISA. Thus, therapeutic immunization stimulates an immune response, which reduces H. pylori infection via a mechanism that is antibody independent. How this is achieved remains to be determined, but may well involve a novel immune mechanism.