Bacterial lipoprotein-induced tolerance is reversed by overexpression of IRAK-1

Tolerance to bacterial cell wall components including bacterial lipoprotein (BLP) represents an essential regulatory mechanism during bacterial infection. Reduced Toll-like receptor 2 (TLR2) and IL-1 receptor-associated kinase 1 (IRAK-1) expression is a characteristic of the downregulated TLR signaling pathway observed in BLP-tolerised cells. In this study, we attempted to clarify whether TLR2 and/or IRAK-1 are the key molecules responsible for BLP-induced tolerance. Transfection of HEK293 cells and THP-1 cells with the plasmid encoding TLR2 affected neither BLP tolerisation-induced NF-κB deactivation nor BLP tolerisation-attenuated pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) production, indicating that BLP tolerance develops despite overexpression of TLR2 in these cells. In contrast, overexpression of IRAK-1 reversed BLP-induced tolerance, as transfection of IRAK-1 expressing vector resulted in a dose-dependent NF-κB activation and TNF-α release in BLP-tolerised cells. Furthermore, BLP-tolerised cells exhibited markedly repressed NF-κB p65 phosphorylation and impaired binding of p65 to several pro-inflammatory cytokine gene promoters including TNF-α and interleukin-6 (IL-6). Overexpression of IRAK-1 restored the nuclear transactivation of p65 at both TNF-α and IL-6 promoters. These results indicate a crucial role for IRAK-1 in BLP-induced tolerance, and suggest IRAK-1 as a potential target for manipulation of the TLR-mediated inflammatory response during microbial sepsis.

NF-κB activation is critical for bacterial lipoprotein tolerance-enhanced bactericidal activity in macrophages during microbial infection (116.15)

Tolerance to bacterial cell-wall components including gram-positive bacterial lipoprotein (BLP) represents an essential regulatory mechanism during bacterial infection. Our previous work has demonstrated that BLP-induced tolerance, characterised by hyporesponsiveness in producing proinflammatory cytokines and simultaneously enhanced antimicrobial functions, protects against microbial sepsis-related lethality. However, the underlying mechanisms remain unidentified. In this study we reported that upon S. aureus or E. coli challenge, significantly enhanced IκBα phosphorylation and p65 translocation into the nucleus were observed in BLP-tolerised bone marrow-derived macrophages (BMM), indicating that NF-κB is activated in BLP-tolerised macrophages during bacteria infection. To further clarify whether activation of the NF-κB pathway is required for efficient bacterial killing by BLP-tolerised macrophages, we used two NF-κB inhibitors, SN50 and SC-154. Both inhibitors substantially restrained BLP-tolerised macrophage-induced intracellular bacterial killing, and this was closely associated with delayed phagolysosome fusion. Furthermore, the expression of LAMP-1 and Rab5, two membrane-trafficking regulators participated the process of phagosome maturation was significantly downregulated when the NF-κB pathway was blocked. Collectively, our results highlight a novel role of the NF-κB pathway in bactericidal activity displayed by BLP-tolerised macrophages during microbial infection.

B7-H3 augments the inflammatory response and is associated with human sepsis

B7-H3, a new member of the B7 superfamily, acts as both a T cell costimulator and coinhibitor, and thus plays a key role in the regulation of T cell-mediated immune responses. However, it is unclear whether B7-H3 is involved in the innate immune monocyte/macrophage-mediated inflammatory response. In this paper, we show that, although B7-H3 alone failed to stimulate proinflammatory cytokine release from murine macrophages, it strongly augmented both LPS- and bacterial lipoprotein-induced NF-kappaB activation and inflammatory response. This occurred in both a TLR4- and TLR2-dependent manner. Blockage of B7-H3 in vivo attenuated LPS-induced proinflammatory cytokine release and endotoxic shock-related lethality. Furthermore, we found that patients diagnosed with sepsis, in contrast to healthy individuals, exhibited significant levels of raised plasma soluble B7-H3 (sB7-H3) and that this level correlated with the clinical outcome and levels of plasma TNF-alpha and IL-6. In addition, a putative receptor for B7-H3 was detected on monocytes and peritoneal macrophages from septic patients but not on monocytes from healthy donors. Stimulation of human monocytes with LPS and inflammatory cytokines led to a substantial release of sB7-H3. Taken together, our data indicate that significantly elevated plasma sB7-H3 in septic patients may predict a poor outcome. Furthermore, we demonstrate that B7-H3 functions as a costimulator of innate immunity by augmenting proinflammatory cytokine release from bacterial cell wall product-stimulated monocytes/macrophages and may contribute positively to the development of sepsis.

The Benefits of an Interactive, Individualized Online Patient Pathway for Patients Undergoing Minimally Invasive Radioguided Parathyroidectomy: A Prospective, Double-Blinded, Randomized Clinical Trial

Aim. This study determined the usefulness of an interactive, individualized online patient pathway to patients undergoing elective operation for nonmalignant disease. Methods. An exploratory double-blind, prospective randomized controlled trial was established involving consecutive patients undergoing minimally invasive radioguided parathyroidectomy (MIRP). A total of 64 patients were randomly assigned to either a standard or an enhanced Web site (interactive with detailed, personalized timeline). Each patient completed validated Hospital Anxiety and Depression Scale questionnaires preoperatively and pain assessments and questionnaires concerning Web site usefulness postoperatively. Results . All patients found their Web site useful, although patient satisfaction was significantly higher with the enhanced Web site in regard to overall impression as well as ease, organization, usefulness, and specificity of information. There were no significant differences in mean anxiety or pain scores, in analgesia requirements, or adequacy of informed consent. Conclusion. Providing education and information through a tailored Web server is viewed positively by patients.

Hypoxia increases the metastatic ability of breast cancer cells via upregulation of CXCR4

BACKGROUND

Chemokine SDF1alpha and its unique receptor CXCR4 have been implicated in organ-specific metastases of many cancers including breast cancer. Hypoxia is a common feature of solid tumors and is associated with their malignant phenotype. We hypothesized that hypoxia would upregulate CXCR4 expression and lead to increased chemotactic responsiveness to its specific ligand SDF1alpha.

METHODS

Three breast cancer cell lines MDA-MB-231, MCF7 and 4T1 were subjected to 48 hrs of hypoxia or normoxia. Cell surface receptor expression was evaluated using flow cytometry. An extracellular matrix invasion assay and microporous migration assay was used to assess chemotactic response and metastatic ability.

RESULTS

CXCR4 surface expression was significantly increased in the two human breast cancer cell lines, MDA-MB-231 and MCF7, following exposure to hypoxia. This upregulation of CXCR4 cell surface expression corresponded to a significant increase in migration and invasion in response to SDF1-alpha in vitro. The increase in metastatic potential of both the normoxic and the hypoxic treated breast cancer cell lines was attenuated by neutralization of CXCR4 with a CXCR4 neutralizing mAb, MAB172 or a CXCR4 antagonist, AMD3100, showing the relationship between CXCR4 overexpression and increased chemotactic responsiveness.

CONCLUSIONS

CXCR4 expression can be modulated by the tissue microenvironment such as hypoxia. Upregulation of CXCR4 is associated with increased migratory and invasive potential and this effect can be abrogated by CXCR4 inhibition. Chemokine receptor CXCR4 is a potential therapeutic target in the adjuvant treatment of breast cancer.

ST2 negatively regulates TLR2 signaling, but is not required for bacterial lipoprotein-induced tolerance

Activation of TLR signaling is critical for host innate immunity against bacterial infection. Previous studies reported that the ST2 receptor, a member of the Toll/IL-1 receptor superfamily, functions as a negative regulator of TLR4 signaling and maintains LPS tolerance. However, it is undetermined whether ST2 negatively regulates TLR2 signaling and furthermore, whether a TLR2 agonist, bacterial lipoprotein (BLP)-induced tolerance is dependent on ST2. In this study, we show that BLP stimulation-induced production of proinflammatory cytokines and immunocomplex formation of TLR2-MyD88 and MyD88-IL-1R-associated kinase (IRAK) were significantly enhanced in ST2-deficient macrophages compared with those in wild-type controls. Furthermore, overexpression of ST2 dose-dependently attenuated BLP-induced NF-kappaB activation, suggesting a negative regulatory role of ST2 in TLR2 signaling. A moderate but significantly attenuated production of TNF-alpha and IL-6 on a second BLP stimulation was observed in BLP-pretreated, ST2-deficient macrophages, which is associated with substantially reduced IRAK-1 protein expression and downregulated TLR2-MyD88 and MyD88-IRAK immunocomplex formation. ST2-deficient mice, when pretreated with a nonlethal dose of BLP, benefitted from an improved survival against a subsequent lethal BLP challenge, indicating BLP tolerance develops in the absence of the ST2 receptor. Taken together, our results demonstrate that ST2 acts as a negative regulator of TLR2 signaling, but is not required for BLP-induced tolerance.

Mycotic aneurysm of the popliteal artery secondary to Streptococus pneumoniae: a case report and review of the literature

INTRODUCTION

Cases of true mycotic popliteal artery aneurysm are rare. Presentation is variable but invasive and non-invasive investigations collectively facilitate diagnosis and guide operative procedures. Definitive treatment generally utilizes surgical intervention with excision and reconstruction using autologous vein graft. Prolonged targeted antibiotic therapy is an important adjuvant.

CASE PRESENTATION

We describe the clinical presentation, radiological investigations and strategies on the management of a 47-year-old Caucasian Irish man who presented with a mycotic aneurysm of the popliteal artery due to thromboembolisation from Streptococus pneumoniae endocarditis.

CONCLUSION

Cases of true mycotic popliteal artery aneurysms are rare. To the best of our knowledge this is the first documented case of a popliteal artery mycotic aneurysm developing secondary to Streptococus pneumoniae highlighting the changing profile of causative microorganisms.

Bacterial endotoxin enhances colorectal cancer cell adhesion and invasion through TLR-4 and NF-kappaB-dependent activation of the urokinase plasminogen activator system

Perioperative exposure to lipopolysaccharide (LPS) is associated with accelerated metastatic colorectal tumour growth. LPS directly affects cells through Toll-like receptor 4 (TLR-4) and the transcription factor NF-κB. The urokinase plasminogen activator (u-PA) system is intimately implicated in tumour cell extracellular matrix (ECM) interactions fundamental to tumour progression. Thus we sought to determine if LPS directly induces accelerated tumour cell ECM adhesion and invasion through activation of the u-PA system and to elucidate the cellular pathways involved. Human colorectal tumour cell lines were stimulated with LPS. u-PA concentration, u-PA activity, active u-PA, surface urokinase plasminogen activator receptor (u-PAR) and TLR-4 expression were assessed by ELISA, colorimetric assay, western blot analysis and flow cytometry respectively. In vitro tumour cell vitronectin adhesion and ECM invasion were analysed by vitronectin adhesion assay and ECM invasion chambers. u-PA and u-PAR function was inhibited with anti u-PA antibodies or the selective u-PA inhibitors amiloride or WXC-340, TLR-4 by TLR-4-blocking antibodies and NF-κB by the selective NF-κB inhibitor SN-50. LPS upregulates u-PA and u-PAR in a dose-dependent manner, enhancing in vitro tumour cell vitronectin adhesion and ECM invasion by >40% (P<0.01). These effects were ameliorated by u-PA and u-PAR inhibition. LPS activates NF-κB through TLR-4. TLR-4 and NF-κB inhibition ameliorated LPS-enhanced u-PA and u-PAR expression, tumour cell vitronectin adhesion and ECM invasion. LPS promotes tumour cell ECM adhesion and invasion through activation of the u-PA system in a TLR-4- and NF-κB-dependent manner.

Analysis of differential gene expression in colorectal cancer and stroma using fluorescence-activated cell sorting purification

Tumour stroma gene expression in biopsy specimens may obscure the expression of tumour parenchyma, hampering the predictive power of microarrays. We aimed to assess the utility of fluorescence-activated cell sorting (FACS) for generating cell populations for gene expression analysis and to compare the gene expression of FACS-purified tumour parenchyma to that of whole tumour biopsies. Single cell suspensions were generated from colorectal tumour biopsies and tumour parenchyma was separated using FACS. Fluorescence-activated cell sorting allowed reliable estimation and purification of cell populations, generating parenchymal purity above 90%. RNA from FACS-purified and corresponding whole tumour biopsies was hybridised to Affymetrix oligonucleotide microarrays. Whole tumour and parenchymal samples demonstrated differential gene expression, with 289 genes significantly overexpressed in the whole tumour, many of which were consistent with stromal gene expression (e.g., COL6A3, COL1A2, POSTN, TIMP2). Genes characteristic of colorectal carcinoma were overexpressed in the FACS-purified cells (e.g., HOX2D and RHOB). We found FACS to be a robust method for generating samples for gene expression analysis, allowing simultaneous assessment of parenchymal and stromal compartments. Gross stromal contamination may affect the interpretation of cancer gene expression microarray experiments, with implications for hypotheses generation and the stability of expression signatures used for predicting clinical outcomes.

Subcutaneous endometrial deposit: an unusual cause of right iliac fossa pain

This case illustrates the use of ultrasound in identifying endometrioma and the capability of ultrasound-guided biopsy in providing definitive histological diagnosis of this rare condition.

Combined IFN-gamma-endostatin gene therapy and radiotherapy attenuates primary breast tumor growth and lung metastases via enhanced CTL and NK cell activation and attenuated tumor angiogenesis in a murine model

BACKGROUND

Gene-radiotherapy, a combination of gene therapy and radiotherapy, is a new paradigm for cancer treatment, with the potential to simultaneously improve local and systemic breast cancer control. The aim of this study was to evaluate antitumor effect of interferon (IFN)-gamma-endostatin-based gene-radiotherapy in a murine metastatic breast tumor model, and to elucidate possible mechanisms involved.

METHODS

Murine mammary adenocarcinoma 4T1 cells transfected with pEgr-IFN-gamma and pEgr-endostatin plasmids were irradiated (2-20 Gy). IFN-gamma and endostatin levels in the culture supernatants were measured. In vivo female BALB/c mice were inoculated with 1 x 10(5) 4T1 cells by mammary fat pad injection and divided into control, empty vector, gene therapy (pEgr-IFN-gamma and pEgr-endostatin), radiotherapy, and combined gene-radiotherapy groups. Tumor growth, tumor/body weight ratio, lung metastases, and survival of the tumor-bearing mice were observed. Splenic cytotoxic T-lymphocyte (CTL) and natural killer (NK) cell activity and intratumor microvessel density were also assessed.

RESULTS

Irradiation significantly enhanced IFN-gamma and endostatin secretion from the transfected 4T1 cells. In vivo mice that received combined gene-radiotherapy showed maximal attenuation in tumor growth rate and lung metastases with increased survival compared with mice that received gene therapy or radiotherapy alone. This was associated with significantly enhanced CTL and NK cell activity and reduced intratumor microvessel density.

CONCLUSION

These results demonstrate that IFN-gamma-endostatin-based gene-radiotherapy provide a potent antitumor effect in a murine metastatic breast tumor model, which may relate to IFN-gamma-stimulated CTL and NK cell activation, and endostatin-induced antiangiogenic activity. Thus, gene-radiotherapy may represent a useful addition to neoadjuvant management of locally advanced breast cancer.

Intracystic papillary carcinoma in a male as a rare presentation of breast cancer: a case report and literature review

Introduction

The term "intracystic papillary ductal carcinoma in situ" has recently changed and is now more appropriately referred to "intracystic papillary carcinoma". Intracystic papillary carcinoma in men is an extremely rare disease with only a few case presentations published in the literature so far.

Case presentation

We discuss a case of a 44-year-old Caucasian man with an intracystic papillary carcinoma treated with simple mastectomy, sentinel lymph-node biopsy and contralateral risk-reducing mastectomy. These were followed by adjuvant radiotherapy of the breast.

Conclusion

Triple assessment (i.e. clinical examination and radiological and histological assessment) with a high level of clinical suspicion is necessary to diagnose intracystic papillary carcinoma in men due to its rarity. Furthermore, genetic testing and risk-reducing mastectomy should also be considered in cases of a strong family history for male breast cancer.

Influence of delays on perforation risk in adults with acute appendicitis

PURPOSE

This study analyzed whether prehospital or in-hospital delay was the more significant influence on perforation rates for acute appendicitis and whether any clinical feature designated patients requiring higher surgical priority.

METHODS

A retrospective analysis was conducted over one year at a tertiary referral hospital without a dedicated emergency surgical theater. Admission notes, theater logbook, and the Hospital Inpatient Enquiry system were reviewed to identify the characteristics and clinical course of patients aged greater than 16 years who were operated upon for histologically confirmed acute appendicitis.

RESULTS

One hundred and fifteen patients were studied. The overall perforation rate was 17 percent. The mean duration of symptoms prior to hospital presentation was 38.1 hours with the mean in-hospital waiting time prior to operation being 23.4 hours. Although body temperature on presentation was significantly greater in patients found to have perforated appendicitis (P < 0.05), only patient heart rate at presentation and overall duration of symptoms, but not in-hospital waiting time, independently predicted perforation by stepwise linear regression modeling.

CONCLUSION

In-hospital delay was not an independent predictor of perforation in adults with acute appendicitis although delays may contribute if patients are left to wait unduly. Tachycardia at presentation may be a quantifiable feature of those more likely to have perforation and who should be given higher surgical priority.

Recombinant bactericidal permeability increasing protein (rBPI21) inhibits surgery-induced tumour growth in a murine model of metastatic disease

BACKGROUND

Endotoxin (LPS), a cell wall constituent of gram-negative bacteria, is a potent inflammatory stimulus. We demonstrated that laparotomy increases primary tumour growth and experimental lung metastases, implicating endotoxin as a causative factor. We hypothesised that the anti-endotoxin agent, rBPI(21) would block surgery-induced tumour growth.

METHODS

Mammary adenocarcinoma cells were injected into female BALB/c mice to establish lung metastases. Mice were randomised into three groups receiving anaesthesia, laparotomy or laparotomy and rBPI(21) treatment on day 14. Animals were killed on day 19, lungs harvested and blood obtained. Number and size of lung metastases were recorded. Apoptosis, mitosis and microvessel density within metastases were assessed and VEGF measured.

CONCLUSIONS

Laparotomy increased metastatic growth, decreased tumour cell apoptosis, increased tumour cell proliferation, increased microvessel density and circulating VEGF. LPS blockade by rBPI(21) attenuated this increased growth and decreased proliferation, increased apoptosis, decreased micro-vessel density and circulating VEGF. This suggests that rBPI(21), has clinical potential in attenuating surgery enhanced tumour growth, especially in patients with a history of cancer undergoing laparotomy.

Cytokine orchestration in post-operative peritoneal adhesion formation

Peritoneal adhesions are a near inevitable occurrence after laparotomy and a major cause of both patient and physician misery. To date, clinical attempts at their amelioration have concentrated on manipulating the physical factors that affect their development despite a wealth of experimental data elucidating the molecular mechanisms that underlie their initiation, development and maturation. However, the advent of targeted, specific anti-cytokine agents as directed therapy for inflammatory and neoplastic conditions raises the prospect of a new era for anti-adhesion strategies. To harness this potential will require considerable cross-disciplinary collaboration and that surgeon-scientists propel themselves to the forefront of this emerging field.

Sulphomucin expression in ileal pouches: emerging differences between ulcerative colitis and familial adenomatous polyposis pouches

PURPOSE

We characterized the expression of sialomucin and sulphomucin in pouches fashioned for familial adenomatous polyposis and ulcerative colitis. We correlated sulphomucin expression with bacterial colonization and mucosal inflammation.

METHODS

Ethical approval and informed consent were obtained. Mucosal biopsies from 9 patients with familial adenomatous polyposis and 12 with ulcerative colitis were obtained. Sulphomucin levels were assessed by using the high iron-diamine stain. Mucous gel layer composition was correlated with villous height, crypt depth, and total mucosal thickness. Mucous gel layer composition was correlated with acute and chronic inflammatory infiltrates. Colonization by a panel of seven bacterial species (including sulphate reducing bacteria) was established and correlated with sulphomucin levels.

RESULTS

High-iron-diamine positivity (i.e., sulphomucin expression) was greater in ulcerative colitis pouch mucous gel (2.083 +/- 0.5 vs. 0.556 +/- 0.4, P = 0.003). Sulphomucin expression correlated with reduced crypt depth, villous height, and total mucosal thickness. In the ulcerative colitis group, chronic inflammatory infiltrate scores were significantly greater for high-iron-diamine-positive patients. Colonization by sulphate reducing bacteria was increased in high-iron-diamine-positive patients.

CONCLUSIONS

Sulphomucin expression is increased in the mucous gel layer of the ulcerative colitis pouch compared with that of the familial adenomatous polyposis pouch. Sulphomucin expression is associated with colonization by sulphate-reducing bacteria and increased chronic inflammation.

Postoperative phlegmasia caerulea dolens: a case report and consideration of potential iatrogenic factors

While the haemorrhagic consequences of anti-coagulants are well and frequently described in the surgical literature, the paradoxical prothrombotic tendencies of these drugs tend to be under-recognised due, perhaps, to their clinical infrequency. However, when these effects pertain, their consequences can be devastating. Here, we present a postoperative oncology patient who suffered a massive recrudescence of his lower limb venous thrombosis immediately after discontinuation of his heparin infusion, despite seemingly being adequately anticoagulated by warfarin therapy (INR > 2.0). We intend this case to graphically illustrate the theoretical considerations that must govern the perioperative use of these drugs in high-risk patients.

Taurolidine induces apoptosis of murine melanoma cells in vitro and in vivo by modulation of the Bcl-2 family proteins

BACKGROUND

This study evaluates whether taurolidine, a novel antibiotic agent, induces murine melanoma cell apoptosis in vitro and in vivo.

METHODS

Murine melanoma cells (B16 4A5 and B16 F10) were treated with taurolidine (0-100 microM) for 12 and 24 hr. Cell viability and apoptosis were assessed by MTT assay and FACScan analysis. Expression of the Bcl-2 family proteins was detected by Western blot analysis. In vivo, taurolidine-induced anti-tumor cytotoxicity was assessed in C57BL/6 mice. Therapeutic effectiveness, by intraperitoneal injection of taurolidine (15 mg/mouse) on alternate days for 2 weeks, was evaluated in mice bearing B16 4A5 tumor xenografts. Primary and metastatic tumor growth and intra-tumor apoptotic index were measured.

RESULTS

Taurolidine induced cell apoptosis and reduced cell viability in murine melanoma cells. The pro-apoptotic protein Bax was enhanced, whereas the anti-apoptotic protein Bcl-2 was inhibited by taurolidine treatment. In vivo, systemic injection of 15-mg taurolidine was identified as the maximally tolerated dose. Administration of taurolidine at 15 mg/mouse significantly inhibited primary and metastatic tumor growth, which was mirrored by a significantly increased intra-tumor apoptotic index.

CONCLUSIONS

These results demonstrate that taurolidine significantly attenuated melanoma tumor growth, which may result from taurolidine-induced apoptosis by modulation of the Bcl-2 family proteins.

Tolerization with BLP down-regulates HMGB1-a critical mediator of sepsis-related lethality

Tolerization with bacterial lipoprotein (BLP) affords a significant survival benefit in sepsis. Given that high mobility group box protein-1 (HMGB1) is a recognized mediator of sepsis-related lethality, we determined if tolerization with BLP leads to alterations in HMGB1. In vitro, BLP tolerization led to a reduction in HMGB1 gene transcription. This was mirrored at the protein level, as HMGB1 protein expression and release were reduced significantly in BLP-tolerized human THP-1 monocytic cells. BLP tolerance in vivo led to a highly significant, long-term survival benefit following challenge with lethal dose BLP in C57BL/6 mice. This was associated with an attenuation of HMGB1 release into the circulation, as evidenced by negligible serum HMGB1 levels in BLP-tolerized mice. Moreover, HMGB1 levels in peritoneal macrophages from BLP-tolerized mice were reduced significantly. Hence, tolerization with BLP leads to a down-regulation of HMGB1 protein synthesis and release. The improved survival associated with BLP tolerance could thus be explained by a reduction in HMGB1, were the latter associated with lethality in BLP-related sepsis. In testing this hypothesis, it was noted that neutralization of HMGB1, using anti-HMGB1 antibodies, abrogated BLP-associated lethality almost completely. To conclude, tolerization with BLP leads to a down-regulation of HMGB1, thus offering a novel means of targeting the latter. HMGB1 is also a mediator of lethality in BLP-related sepsis.

Daily Diurnal Variation in Admissions for Ruptured Abdominal Aortic Aneurysms

BACKGROUND

Many vascular events, such as myocardial infarction and cerebrovascular accident, demonstrate a circadian pattern of presentation. Blood pressure is intimately related to these pathologies and is the one physiological variable consistently associated with abdominal aortic aneurysm rupture. It also demonstrates a diurnal variation. The purpose of this study was to determine if rupture of an abdominal aortic aneurysm (RAAA) exhibits a diurnal variation.

METHODS

A retrospective cohort-based study was performed to determine the timing of presentation of RAAA to the vascular unit of Cork University Hospital over a 15-year period. Time of admission, symptom onset, and co-morbidities such as hypertension were noted. Fournier's analysis and chi-squared analysis were performed. To ameliorate possible confounding factors, patients admitted with perforated peptic ulcers were examined in the same manner.

RESULTS

A total of 148 cases of RAAA were identified, with a male preponderance (71.7% [124] male versus 29.3% [44] female patients) and a mean age of 74.4 +/- 7.2 years at presentation. 70.9% (105) were known to have hypertension, 52.2% (77) were current smokers, and 46.8% (69) were being treated for chronic obstructive airway disease (COAD). Time of symptom onset was recorded in 88.5% (131) of patients. There was a marked early morning peak in RAAA admissions, with the highest number of RAAA being admitted between 08.00 and 09.59. A second, smaller peak was observed at 14.00-15.59. These findings were suggestive of diurnal variation. [chi(2) =16.75, p < 0.003]. Some 40% (59) of patients were admitted between 00.00 and 06.00, an incidence significantly higher than for other time periods (06.00-12.00, 12.00-18.00, and 18.00-24.00) [chi(2) = 18.72; df = 3; p < 0.0003]. A significantly higher number of patients admitted between 00.00 and 06.00 were known hypertensives (chi(2) = 7.94; p < 0.05).

CONCLUSIONS

The findings of this study suggest a distinct circadian pattern of presentation for RAAA. Systolic blood pressure has a circadian rhythm that mirrors this pattern of presentation. Our results further support the association between RAAA and hypertension, and they may also indicate that chronotropic blood pressure control combating the early-morning peak in systolic blood pressure may assist in the management of abdominal aortic aneurysms.

Salmonella typhimurium stimulation combined with tumour-derived heat shock proteins induces potent dendritic cell anti-tumour responses in a murine model

Appropriate activation of the immune system and effective targeting of tumour cells are the primary hurdles to be overcome for cancer immunotherapy to be successful and applicable to a wide range of tumour types. Our studies have examined the ability of bacterial-stimulated dendritic cells (DCs), loaded with tumour-associated antigens, to inhibit tumour growth in a murine model. Immature murine bone marrow-derived DCs were stimulated in vitro with the cytoplasmic fraction (CM) of Salmonella typhimurium in combination with heat shock proteins (hsps) from 4T1 tumours, isolated using heparin affinity chromatography. Activated DCs were administered subcutaneously. Tumours were generated by orthotopic inoculation of 4T1 cells in Balb/c mice. Primary tumour growth was measured using Vernier calipers, while lung metastases were measured using the clonogenic assay. S. typhimurium CM induced potent tumour necrosis factor (TNF)-alpha responses from DCs accompanied by significant up-regulation of CD80 and CD86 expression. When injected into mice, bacterial-stimulated DCs loaded with 4T1 hsps inhibited the formation of new 4T1 tumours and reduced the growth rate of established tumours. In addition, the number of lung metastatic nodules was reduced significantly in the DC-treated mice (1.6 +/- 0.6 versus 245.9 +/- 55.6, P = 0.0015). DCs stimulated with CM alone, exposed to tumour hsps alone or exposed to tumour hsps from an unrelated tumour cell line did not induce a protective immune response. Dendritic cells primed with a proinflammatory bacterial stimulus and tumour-associated antigens induce a protective anti-tumour immune response in this murine model.

Contemporary management of drug-packers

Experience with management of drug-packers (mules) is variable among different centres. However, despite a recorded increase in drug trafficking in general, as yet, no unified, clear guidelines exist to guide the medical management of those who only occasionally encounter these individuals. We describe our recent experience with this growing problem and discuss the most salient points concerning the contemporary management of body packers. Our recent experience demonstrates that type IV packages may now be managed conservatively for the most part.

Evaluation of postoperative peritoneal adhesion formation following perioperative nicotine administration

PURPOSE

The primary step in postoperative peritoneal adhesion formation involves the exudation of fibrin through permeable mesenteric capillaries. Nicotine, the most potent constituent of cigarette smoke, augments the release of vascular endothelial growth factor (VEGF), which increases vascular permeability. The objective of this study was to evaluate the effect of nicotine on postlaparotomy abdominal adhesions.

METHODS

CD-1 mice were randomized to receive, ad libitum, either water alone (as 2% sucrose solution) or water mixed with 100 microg/mL nicotine (to obtain blood levels equivalent to a 1 pack/day smoker) (n = 32 mice per group). After 1 wk, all mice underwent laparotomy to induce adhesion formation using the same experimental method (consisting of laparotomy with cecal abrasion to achieve serosal punctuate hemorrhage). Fourteen days later, all animals were sacrificed for adhesion grading (0 to 3) by a blinded observer. Additionally, peritoneal lavage fluid from separate mice receiving either water or nicotine water before their surgery or else undergoing sham laparotomy was retrieved at 2, 6, and 24 h postoperatively (4 mice per group/time point) and assessed for VEGF concentrations.

RESULTS

The nicotine treated group had a mean +/- SEM adhesion score of 2.4 +/- 0.2, which was significantly greater than that of the control group (1.2 +/- 0.2) (P < 0.05, Mann Whitney U test.). This correlated with a significant increase in peritoneal VEGF levels occurring at 6 and 24 h in the nicotine group.

CONCLUSION

Peritoneal adhesion formation after surgery is increased in mice receiving nicotine perioperatively. This effect may be mediated through a direct augmentation of peritoneal VEGF release by nicotine with a subsequent increase in mesenteric endothelial permeability. These findings could have significant implications for smokers undergoing intra-abdominal surgical procedures.

Inhibition of urokinase plasminogen activator with a novel enzyme inhibitor, WXC-340, ameliorates endotoxin and surgery-accelerated growth of murine metastases

The urokinase plasminogen activator (u-PA) is intimately associated with tumour invasion and metastases. Surgery facilitates accelerated metastatic tumour growth in murine models, a phenomenon related to elevated perioperative bacterial lipopolysaccaride (LPS) and inflammatory cytokine levels. The objectives of the study were to examine the role of u-PA in cytokine-enhanced tumour cell invasion in vitro and surgery-induced accelerated metastatic tumour growth in vivo and to assess the potential benefit of a novel selective u-PA inhibitor WXC-340 in this setting. CT-26 murine colorectal carcinoma cells were stimulated with LPS, tumour necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6). Cell supernatant u-PA expression and activity were determined using a colorimetric assay and Western blot analysis, respectively. Baseline and cytokine-stimulated in vitro invasion were assessed using ECmatrix invasion chambers. Two established murine models of accelerated metastatic tumour growth were used to investigate the consequences of u-PA inhibition on postoperative metastatic tumour burden. The effect of u-PA inhibition in vitro and in vivo was examined using the novel selective u-PA inhibitor, WXC-340. Proinflammatory cytokine stimulation significantly enhanced in vitro u-PA expression, activity and extracellular matrix invasion by approximately 50% compared to controls (P<0.05). This was abrogated by WXC-340. In vivo WXC-340 almost completely ameliorated both LPS- and surgery-induced, metastatic tumour growth compared to controls (P>0.05). In conclusion, u-PA cascade is actively involved in cytokine-mediated enhanced tumour cell invasion and LPS and surgery-induced metastatic tumour growth. Perioperative u-PA inhibition with WXC-340 may represent a novel therapeutic paradigm.

Treatment of sepsis: current status of clinical immunotherapy

While antibiotics address the root cause of sepsis--that of pathogen infection--they fail to provide an adequate cure for the condition. Currently, 30% to 50% of septic patients die, and this figure is likely to increase in line with the proliferation of multi-drug resistant bacteria. With an increased understanding of the immune response, it has been proposed that modulation of this defence mechanism offers the best hope of cure. Many entry-points in the immune system have been identified and targeted therapies have been developed,but why are these not in routine clinical practice? This review examines the latest evidence for the use of immuno-modulating drugs, obtained from human clinical trials. We discuss cytokine-based therapies, steroids and anti-coagulants. Finally, consideration is given as to why successful therapies in the laboratory, and in vivo models, do not automatically translate into clinical benefit

Enteric bacteria and their antigens may stimulate postoperative peritoneal adhesion formation

BACKGROUND

Intraabdominal sepsis causes exuberant inflammation, which results in dense adhesions. Translocation of enteric bacteria and/or their antigens after laparotomy may therefore also affect peritoneal healing by promoting local release of proinflammatory cytokines. Our hypothesis was that targeted counter therapy could be beneficial if such contamination was to augment postoperative adhesion formation.

METHODS

Two endotoxin-hyposensitive mouse strains (C3H/HeJ and C57BL/10ScCr) and their syngeneic counterparts (C3H/HeN and C57BL10/ScSn, respectively) underwent reproducible adhesion-inducing operation (AIO) (n=10/group) with sacrifice and blinded adhesion grading 14 days later. In addition, CD-1 mice were gavaged with fluorescein isothiocyanate labeled-lipopolysaccharide (FITC-LPS) prior to either AIO or sham laparotomy and had both peritoneal macrophages and circulating monocytes assessed by flow cytometry afterward. The cytokine-release response of resident peritoneal cells to LPS stimulation was assessed in vitro (murine peritoneal mast cell cultures) and in vivo (unoperated CD-1 mice administered LPS intraperitoneally [10 & 50 microg/mouse]). Finally, CD-1 mice (n=10/group) had AIO and received either bactericidal/permeability increasing protein (rBPI, 2 mg/mouse) or vehicle solution in the early postoperative period with assessment of adhesion formation 2 weeks later.

RESULTS

Both HeJ and ScCr mice had less adhesions than their controls (P=.0015 and .0001, respectively, Mann Whitney U test). FITC-LPS uptake by peritoneal macrophages was striking after AIO. Intraperitoneal LPS provoked significant local vascular endothelial growth factor (VEGF) release as did the process of AIO. In vitro, LPS induced significant interleukin-(IL)-6 release from isolated mast cells. Intraperitoneal administration of rBPI to CD-1 mice early after AIO markedly attenuated subsequent adhesion formation (P=.0003).

CONCLUSIONS

Peritoneal adhesion formation is exacerbated by peritoneal contamination due to translocation after laparotomy and may be attenuated by therapeutic antagonism.

Cell response to surgery

OBJECTIVES

To describe the profound alterations in host immunity that are produced by major surgery as demonstrated by experimental and clinical studies, and to evaluate the benefits of therapeutic strategies aimed at attenuating perioperative immune dysfunction.

DATA SOURCES

A review of the English-language literature was conducted, incorporating searches of the MEDLINE, EMBASE, and Cochrane collaboration databases to identify laboratory and clinical studies investigating the cellular response to surgery.

STUDY SELECTION

Original articles and case reports describing immune dysfunction secondary to surgical trauma were included.

DATA EXTRACTION

The results were compiled to show outcomes of different studies and were compared.

DATA SYNTHESIS

Current evidence indicates that the early systemic inflammatory response syndrome observed after major surgery that is characterized by proinflammatory cytokine release, microcirculatory disturbance, and cell-mediated immune dysfunction is followed by a compensatory anti-inflammatory response syndrome, which predisposes the patient to opportunistic infection, multiple organ dysfunction syndrome, and death. Because there are currently no effective treatment options for multiple organ dysfunction syndrome, measures to prevent its onset should be initiated at an early stage. Accumulating experimental evidence suggests that targeted therapeutic strategies involving immunomodulatory agents such as interferon gamma, granulocyte colony-stimulating factor, the prostaglandin E(2) antagonist, indomethacin, and pentoxifylline may be used for the treatment of systemic inflammatory response syndrome to prevent the onset of multiple organ dysfunction syndrome.

CONCLUSIONS

Surgical trauma produces profound immunological dysfunction. Therapeutic strategies directed at restoring immune homeostasis should aim to redress the physiological proinflammatory-anti-inflammatory cell imbalance associated with major surgery.

A systemic provascular response in bone marrow to musculoskeletal trauma in mice

Post-natal vasculogenesis, the process by which vascular committed bone marrow stem cells or endothelial precursor cells migrate, differentiate and incorporate into the nacent endothelium and thereby contribute to physiological and pathological neurovascularisation, has stimulated much interest. Its contribution to neovascularisation of tumours, wound healing and revascularisation associated with ischaemia of skeletal and cardiac muscles is well established. We evaluated the responses of endothelial precursor cells in bone marrow to musculoskeletal trauma in mice.

Bone marrow from six C57 Black 6 mice subjected to a standardised, closed fracture of the femur, was analysed for the combined expression of cell-surface markers stem cell antigen 1 (sca-1+) and stem cell factor receptor, CD117 (c-kit+) in order to identify the endothelial precursor cell population. Immunomagnetically-enriched sca-1+ mononuclear cell (MNCsca-1+) populations were then cultured and examined for functional vascular endothelial differentiation. Bone marrow MNCsca-1+,c-kit+ counts increased almost twofold within 48 hours of the event, compared with baseline levels, before decreasing by 72 hours.

Sca-1+ mononuclear cell populations in culture from samples of bone marrow at 48 hours bound together Ulex Europus-1, and incorporated fluorescent 1,1′-dioctadecyl- 3,3,3,’3′-tetramethylindocarbocyanine perchlorate-labelled acetylated low-density lipoprotein intracellularily, both characteristics of mature endothelium.

Our findings suggest that a systemic provascular response of bone marrow is initiated by musculoskeletal trauma. Its therapeutic manipulation may have implications for the potential enhancement of neovascularisation and the healing of fractures.

Mobilization of endothelial precursor cells: systemic vascular response to musculoskeletal trauma

Postnatal vasculogenesis, the process by which vascular committed bone marrow stem cells or endothelial precursor cells (EPC) migrate, differentiate, and incorporate into the nacent endothelium contributing to physiological and pathological neovascularization, has stimulated much interest. Its contribution to tumor nonvascularization, wound healing, and revascularization associated with skeletal and cardiac muscles ischaemia is established. We evaluated the mobilization of EPCs in response to musculoskeletal trauma. Blood from patients (n = 15) following AO type 42a1 closed diaphyseal tibial fractures was analyzed for CD34 and AC133 cell surface marker expression. Immunomagnetically enriched CD34+ mononuclear cell (MNC(CD34+)) populations were cultured and examined for phenotypic and functional vascular endothelial differentiation. Circulating MNC(CD34+) levels increased sevenfold by day 3 postinjury. Circulating MNC(AC133+) increased 2.5-fold. Enriched MNC(CD34+) populations from day 3 samples in culture exhibited cell cluster formation with sprouting spindles. These cells bound UEA-1 and incorporated fluorescent DiI-Ac-LDL intracellularily. Our findings suggest a systemic provascular response is initiated in response to musculoskeletal trauma. Its therapeutic manipulation may have implications for the potential enhancement of fracture healing.

Laparoscopic surgery protects against the oncologic adverse effects of open surgery by attenuating endothelial progenitor cell mobilization

BACKGROUND

Endothelial progenitor cells (EPCs) derived from bone marrow incorporate into foci of neovascularization to propagate tumor growth. These cells are mobilized in response to surgical injury. Laparoscopic surgery may protect against the oncologic adverse effects of open surgical tumor excision, and this may be related to attenuated mobilization of EPCs.

METHODS

For this study, 132 C57BL/6 mice were randomized to standardized laparotomy, laparoscopy, or control groups. The animals were killed at 6, 24, 48, and 72 h. Femur bone marrow and peripheral blood were harvested. Bone marrow EPCs were detected by flow cytometric dual staining for the stem cell antigen-1/cKit phenotype. Circulating EPCs were characterized in blood by vascular endothelial growth factor receptor 2 positive/macrophage activating complement-1 negative staining. Separately, 12 C57/bl6 mice bearing 3LL Lewis lung tumors 12 days after laparotomy or laparoscopy had their tumors excised and examined for endothelial cell expression (marker P1H12).

RESULTS

Laparoscopy decreased circulating EPCs and bone-marrow EPC levels, as compared with laparotomy, at all time points. Bone marrow EPC levels were 2.95% +/- 0.32% after laparotomy, as compared with 0.65 +/- 0.21 in the laparoscopy group (p < 0.05). The circulating EPC level in the laparotomy group was 35.2% +/- 6% of cells, as compared with 3.1% +/- 0.2% in the laparoscopy group (p < 0.05). In homogenized tumors, the percentage of P1H12 expression among laparoscopy-treated animals was 22.1% +/- 4.2%, as compared with 39% +/- 8% in the laparotomy group (p < 0.05).

CONCLUSION

Laparoscopy decreased EPC levels in both bone marrow and circulation, resulting in decreased tumor endothelial cell burden. This may represent a novel mechanism by which laparoscopy protects against the oncologic adverse effects of open surgical tumor excision.

Hypertonic saline attenuates colonic tumor cell metastatic potential by activating transmembrane sodium conductance

Hypertonic saline (HTS) suppresses tumor cell-endothelial interactions by reducing integrin expression. This translates into reduced adhesion, migration and metastatic potential. This study determined the relative contributions of hyperosmolarity and sodium-specific hypertonicity on the inhibitory effects of HTS, the intracellular pH and sodium responses to HTS and the role of cytoskeletal remodeling in these changes. Human colonic tumor cells (LS174T) were exposed to lipopolysaccharide under isotonic, hypertonic, sodium-free (N-methyl-D-glucamine), hyperosmolar (mannitol or urea), disrupted cytoskeletal (10 microg/ml cytochalasin D) conditions or in the presence of 5-(N-ethyl-N-isopropyl)amiloride (EIPA). Beta(1) integrin expression was measured flow-cytometrically. Intracellular sodium and pH were measured with confocal laser microscopic imaging. Statistical analysis was performed with analysis of variance, and P < 0.05 was considered significant. Data are represented as mean +/- SEM. Hypertonic exposure attenuated integrin expression (62.03 +/- 4.7% of control, P < 0.04). No discernible effect was observed with sodium-free or hyperosmolar solutions. HTS evoked a cellular alkalinization (by a mean 0.2 pH units) and an increase in cytosolic sodium concentration (by a mean 12.4 mM, P < 0.001) via upregulation of sodium-hydrogen exchange. Disassembly of actin microfilaments by cytochalasin D and antiporter inhibition with EIPA abrogated the effect of hypertonicity on integrin expression and intracellular sodium and pH (P < 0.05). HTS downregulates adhesion molecule expression via a hypertonic, sodium-specific, cytoskeletally mediated mechanism that involves activation of sodium-hydrogen exchange with associated changes in intracellular pH and sodium concentrations.

Mast cells facilitate local VEGF release as an early event in the pathogenesis of postoperative peritoneal adhesions

BACKGROUND

Peritoneal injury sustained at laparotomy may evoke local inflammatory responses that result in adhesion formation. Peritoneal mast cells are likely to initiate this process, whereas vascular permeability/endothelial growth factor (VEGF) may facilitate the degree to which subsequent adhesion formation occurs.

METHODS

Mast cell deficient mice (WBB6F1-/-), along with their mast cell sufficient counterparts (WBB6F1+/+), underwent a standardized adhesion-inducing operation (AIS) with subsequent sacrifice and adhesion assessment 14 days later in a blinded fashion. Additional CD-1 and WBB6F1+/+, and WBB6F1-/- mice were killed 2, 6, 12, and 24 hours after operation for measurement of VEGF by ELISA in systemic serum and peritoneal lavage fluid. Two further groups of CD-1 mice underwent AIS and received either a single perioperative dose of anti-VEGF monoclonal antibody (10 mug/mouse) or a similar volume of IgG isotypic antibody and adhesion formation 2 weeks later was evaluated.

RESULTS

WBB6F1-/- mice had less adhesions then did their WBB6F1+/+ counterparts (median [interquartile range] adhesion score 3[3-3] vs 1.5[1-2] respectively; P < .003). Local VEGF release peaked 6 hours after AIS in both WBB6F1+/+ and CD-1 mice whereas levels remained at baseline in WBB6F1-/- mice. CD-1 mice treated with a single dose of anti-VEGF therapy during operation had less adhesions than controls (2[1.25-2] vs 3[2.25-3], P = .0002).

CONCLUSIONS

Mast cells and VEGF are central to the formation of postoperative intra-abdominal adhesions with mast cells being responsible, either directly or indirectly, for VEGF release into the peritoneal cavity after operation. In tandem with the recent clinical success of anti-VEGF monoclonal antibodies in oncologic practice, our observations suggest an intriguing avenue for research and development of anti-adhesion strategy.

Exploitation of the Toll-like receptor system in cancer: a doubled-edged sword?

The toll-like receptor (TLR) system constitutes a pylogenetically ancient, evolutionary conserved, archetypal pattern recognition system, which underpins pathogen recognition by and activation of the immune system. Toll-like receptor agonists have long been used as immunoadjuvants in anti cancer immunotherapy. However, TLRs are increasingly implicated in human disease pathogenesis and an expanding body of both clinical and experimental evidence suggests that the neoplastic process may subvert TLR signalling pathways to advance cancer progression. Recent discoveries in the TLR system open a multitude of potential therapeutic avenues. Extrapolation of such TLR system manipulations to a clinical oncological setting demands care to prevent potentially deleterious activation of TLR-mediated survival pathways. Thus, the TLR system is a double-edge sword, which needs to be carefully wielded in the setting of neoplastic disease.

Cellular reprogramming by gram-positive bacterial components: a review

LPS tolerance has been the focus of extensive scientific and clinical research over the last several decades in an attempt to elucidate the sequence of changes that occur at a molecular level in tolerized cells. Tolerance to components of gram-positive bacterial cell walls such as bacterial lipoprotein and lipoteichoic acid is a much lesser studied, although equally important, phenomenon. This review will focus on cellular reprogramming by gram-positive bacterial components and examines the alterations in cell surface receptor expression, changes in intracellular signaling, gene expression and cytokine production, and the phenomenon of cross-tolerance.

Prospective Study of Use of Perioperative Antimicrobial Therapy in General Surgery

BACKGROUND

Perioperative antimicrobial therapy has demonstrated efficacy in reducing the rate of surgical site infections in clinical trials. With the emergence of antibiotic resistance, the risk of reaction, and the inevitable financial repercussions, use of prophylactic antibiotics is not a panacea, and their misuse may have considerable implications. The aim of this study was to assess the use of antibiotics in the perioperative period in both general and vascular surgery procedures.

METHODS

A prospective study was undertaken of 131 patients with a mean age of 43 years (range one month-88 years), of whom 68 (51%) were male, who underwent twenty-seven different general or vascular surgery procedures over a four-week period. Each patient was evaluated from the time of antibiotic commencement through their operative procedure until the treatment was discontinued.

RESULTS

A total of 73 patients (54%) received ten antibiotics, with 71 (97%) of these uses being prophylactic. Of the 15 appendectomies performed for uncomplicated appendicitis, the mean number of prophylactic antibiotic doses was 5.3 (range 1-12). Where they were documented, written postoperative directives were not adhered to in 18/27 prescriptions (66%).

CONCLUSION

This study has demonstrated a lack of adherence to guidelines in the perioperative administration of antimicrobial agents. In addition, it calls attention to the economic implications of unnecessary prophylaxis.

Co-immunotherapy with interleukin-2 and taurolidine for progressive metastatic melanoma

BACKGROUND

Recombinant interleukin-2(rIL-2) therapy in metastatic melanoma is limited by toxicities, particularly vascular leak syndrome(VLS). Taurolidine potentiates the anti-neoplastic effects of IL-2 while reducing its associated endothelial cell dysfunction in experimental settings. We hypothesized that co-administration of rIL-2 with taurolidine could enhance tolerability without weakening effectiveness.

METHODS

Eleven patients with progressive metastatic melanoma received high-dose rIL-2 with co-infusion of taurolidine. Patients were monitored for the development of toxicities and evidence of response.

RESULTS

Ten patients tolerated twenty-nine courses of high-dose rIL-2 without dose-reduction. Most toxicities were low-grade. No patient developed VLS. Seven patients died from disease progression. Two had complete clinical and radiological responses to treatment. Two patients remain alive despite evidence of disease progression a mean of 17.5 months after diagnosing metastatic disease.

CONCLUSION

Co-administration of taurolidine with high-dose rIL-2 in stage IV melanoma patients appears to greatly enhance the tolerability of this regime without diminishing its therapeutic value.

Sentinel lymph node biopsy: Is it possible to reduce false negative rates by excluding patients with nodular melanoma?

OBJECTIVE

The aim of this study was to review the outcome of sentinel lymph node biopsy (SLNB) in patients with melanoma and to delineate whether patients with nodular melanoma are more likely to develop nodal recurrence despite negative SLNB.

METHODS

Consecutive patients with cutaneous melanoma undergoing SLNB were identified from a departmental database between 1997 and 2005. Factors including demographic data, site, histological subtype, depth and outcome were examined.

RESULTS

Of 131 patients, 103 were node negative and eligible for study. The median age was 53 (16-82) years with 46 patients being male (45%) and 57 female (55%). Primary melanoma sites included lower limb (49; 48%), upper limb (29; 28%), head (12; 11%), trunk (7; 7%) and back (6; 6%). The median Breslow thickness was 2mm. Superficial spreading accounted for 43% of melanoma with nodular accounting for 42%. Median follow-up was 40 (3-90) months. Of 20 relapses, seven recurred in the same nodal basin, three were satellite recurrences, one recurred with both satellite and nodal lesions simultaneously, and nine experienced haematogenous spread. Of the eight patients who developed recurrence in the same nodal basin, four were of nodular histological subtype (p=NS). All of the three patients with satellite lesions had nodular melanoma histologically (p=0.02). When nodal and satellite recurrences were combined, eight of 11 were histologically nodular (p=0.01).

CONCLUSIONS

This study indicates that lymphatic recurrence occurs more often in SLNB negative patients with nodular melanoma. Further evaluation of the inclusion criteria for sentinel node biopsy is warranted.

The targeting of phosphoinositide-3 kinase attenuates pulmonary metastatic tumor growth following laparotomy

OBJECTIVE

We aimed to characterize a potential role for phosphatidylinositol 3-kinase (PI3k) in leading to accelerated postoperative metastatic tumor growth.

BACKGROUND

PI3k enhances tumor cell survival in part by phosphorylating Akt and reducing apoptosis. Postoperatively, apoptosis is reduced within local recurrences and distant metastases. This reduction is associated with the phenomenon of accelerated postoperative tumor growth.

METHODS

Balb/c mice underwent a tail vein injection of 1x10 metastatic murine mammary adenocarcinoma 4T1 cells. Animals were divided into the following treatment groups (n=10/group): group A, controls; group B, DMSO intraperitoneally (IP) daily from days 14 to 21; group C, IP LY294002 daily from days 14 to 21; group D, laparotomy only; group E, laparotomy followed by IP DMSO for 7 days; and group F, laparotomy followed by LY294002 IP for 7 days. All laparotomies were performed on day 14. Animals were killed at day 28. Metastatic tumor burden was assessed using the lung/body weight ratio and a histologic metastatic index. Mitotic counts and apoptotic indices were established using a combination of hematoxylin and eosin histology and TUNEL immunohistochemistry. A parallel survival study was performed, and PI3k activity was assessed using western blots for phospho-Akt.

RESULTS

Laparotomy was associated with increased systemic tumor burden (P=0.001). Postoperatively, LY294002 significantly attenuated metastatic tumor growth (P<0.001). Effective PI3k inhibition was confirmed by demonstrating a reduced Akt phosphorylation. Moreover, PI3k inhibition led to reduced proliferation, increased apoptosis (P<0.001), and enhanced postoperative survival (P<0.001).

CONCLUSIONS

Targeting PI3k with postoperative LY294002 significantly attenuates the acceleration in postoperative metastatic tumor growth seen following laparotomy.

The immunological consequences of injury

Immediate and early trauma death rates are determined by "first hits" such as hypoxia, hypotension and organ injury, while late mortality correlates closely with "second hits" such as infection. An imbalance between the early systemic inflammatory response (SIRS), and the later compensatory counter-inflammatory response (CARS), is considered to be responsible for much post-traumatic morbidity and mortality. From a clinical perspective, this remains a significant healthcare problem, which has stimulated decades of experimental and clinical research aimed at understanding the functional effects of injury on the immune system. This review describes the impact of injury on the innate and adaptive immune systems. Though it is worth noting that the features of the immune response to injury overlap in many areas with immune dysregulation in sepsis, we attempt here to elucidate the mechanism by which injury predisposes to infection rather than to describe the alterations in host immunity consequent to established sepsis.

Rapid Intraoperative Parathyroid Hormone Assay—More than Just a Comfort Measure

BACKGROUND

Minimally invasive radio-guided parathyroidectomy (MIRP) has been embraced as an acceptable therapeutic approach to primary hyperparathyroidism. Preoperative sestamibi scanning has facilitated this technique. Here we evaluate the addition of a rapid intraoperative parathyroid hormone (iPTH) assay for patients undergoing MIRP.

METHODS

A series of 51 patients underwent sestamibi localization of parathyroid glands followed by MIRP for primary hyperparathyroidism. Using peripheral venous samples, iPTH levels were measured prior to gland excision, as well as post-excision at 5, 10, and 15 minutes, taking a 50% reduction in iPTH level as indicative of complete excision. Next, changes in serum iPTH were compared with preoperative and postoperative changes in serum calcium, as well as levels of intraoperative ex-vivo radiation counts taken by hand-held gamma probe.

RESULTS

In this series, a drop of greater than 50% in iPTH levels was observed in 94% of patients (n=48). Moreover, a significant drop in iPTH occurred within 10 minutes of excision in the majority (n=42) of cases (P<0.004). Changes in iPTH were comparable with the therapeutic reduction in calcium levels, as well as with the change in intraoperative ex-vivo gamma counts.

CONCLUSIONS

This study demonstrates that the addition of an iPTH assay to MIRP provides a quick and reliable intraoperative diagnostic modality in confirming correct adenoma removal. Moreover, it precludes the requirement of frozen section.

Bacterial lipoprotein-induced self-tolerance and cross-tolerance to LPS are associated with reduced IRAK-1 expression and MyD88-IRAK complex formation

Tolerance to bacterial cell-wall components may represent an essential regulatory mechanism during bacterial infection. We have demonstrated previously that the inhibition of nuclear factor (NF)-kappaB and mitogen-activated protein kinase activation was present in bacterial lipoprotein (BLP) self-tolerance and its cross-tolerance to lipopolysaccharide (LPS). In this study, the effect of BLP-induced tolerance on the myeloid differentiation factor 88 (MyD88)-dependent upstream signaling pathway for NF-kappaB activation in vitro was examined further. When compared with nontolerant human monocytic THP-1 cells, BLP-tolerant cells had a significant reduction in tumor necrosis factor alpha (TNF-alpha) production in response to a high-dose BLP (86+/-12 vs. 6042+/-245 ng/ml, P < 0.01) or LPS (341+/-36 vs. 7882+/-318 ng/ml, P < 0.01) stimulation. The expression of Toll-like receptor 2 (TLR2) protein was down-regulated in BLP-tolerant cells, whereas no significant differences in TLR4, MyD88, interleukin-1 receptor-associated kinase 4 (IRAK-4), and TNF receptor-associated factor 6 expression were observed between nontolerant and BLP-tolerant cells, as confirmed by Western blot analysis. The IRAK-1 protein was reduced markedly in BLP-tolerant cells, although IRAK-1 mRNA expression remained unchanged as revealed by real-time reverse transcriptase-polymerase chain reaction analysis. Furthermore, decreased MyD88-IRAK immunocomplex formation, as demonstrated by immunoprecipitation, was observed in BLP-tolerant cells following a second BLP or LPS stimulation. BLP pretreatment also resulted in a marked inhibition in total and phosphorylated inhibitor of kappaB-alpha (IkappaB-alpha) expression, which was not up-regulated by subsequent BLP or LPS stimulation. These results demonstrate that in addition to the down-regulation of TLR2 expression, BLP tolerance is associated with a reduction in IRAK-1 expression, MyD88-IRAK association, and IkappaB-alpha phosphorylation. These findings further elucidate the molecular mechanisms underlying bacterial peptide tolerance.

Regulatory T-Cells and Autoimmunity

Approximately 20% of the population is affected by autoimmune or inflammatory diseases mediated by an abnormal immune response. A characteristic feature of autoimmune disease is the selective targeting of a single cell type, organ or tissue by certain populations of autoreactive T-cells. Examples of such diseases include rheumatoid arthritis, insulin-dependent diabetes mellitus, and systemic lupus erythematosus (SLE), all of which are characterized by chronic inflammation, tissue destruction and target organ malfunction. Although strong evidence links most autoimmune diseases to specific genes, considerable controversy prevails regarding the role of regulatory T-cell populations in the disease process. These cells are now also believed to play a key role in mediating transplantation tolerance and inhibiting the induction of tumor immunity. Though the concept of therapeutic immune regulation aimed at treating autoimmune pathology has been validated in many animal models, the development of strategies for the treatment of human autoimmune disorders remains in its infancy. The main obstacles to this include the conflicting findings of different model systems, as well as the contrasting functions of regulatory T-cells and cytokines involved in the development of such disorders. This review examines the role of regulatory T-cells in the pathogenesis of autoimmunity and describes the therapeutic potential of these cells for the prevention of immune-mediated pathologies in the future. Although much remains to be learned about such pathologies, a clearer understanding of the mechanisms by which regulatory T-cells function will undoubtedly lead to exciting new possibilities for immunotherapeutics.

Cancer surgery: risks and opportunities

In the recent past, several papers have pointed to the possibility that tumour removal generates a permissive environment in which tumour growth is potentiated. This phenomenon has been coined "perioperative tumour growth" and whilst it represents a departure in terms of our attitude to the surgical process, this concept was first hinted at by Paget(1) himself. Despite this, the time interval immediately before and after cancer surgery (i.e. the perioperative period) remains an underutilised interval during which chemotherapeutic regimens are rarely implemented. Herein, we present a summarised review of the literature that supports the concept that tumour removal may potentiate the growth of residual neoplastic disease. We also outline current knowledge regarding underlying mechanisms and in this manner highlight potential therapeutic entry points. Finally, we emphasise the urgent need for trials of agents that could protect patients against the harmful host-tumour interactions that may occur during the perioperative period.

The incidence of postoperative venous thrombosis among patients with ulcerative colitis

BACKGROUND

Patients with Ulcerative Colitis (UC) have inherent prothrombotic tendencies. It is unknown whether this necessitates the use of additional perioperative anti-thrombotic prophylaxis when such patients require major surgery.

METHODS

The postoperative courses of 79 patients with UC undergoing 180 major abdominal and pelvic operations were examined for clinical and radiological evidence of venous thrombosis. Eighteen patients with Familial Adenomatous Polyposis (FAP) having surgery (35 operations) of similar magnitude were also studied. Standard anti-thrombosis prophylaxis was utilised in all patients.

RESULTS

Nine patients with UC were clinically suspected of developing postoperative venous thrombosis, but only three (3.8%) had their diagnosis confirmed radiologically (all had a pulmonary embolus). Therefore, the overall postoperative thrombosis rate, on an intention to treat basis, was 1.7% (3/180). No patient with FAP developed significant venous thrombosis.

CONCLUSION

Standard perioperative antithrombotic modalities are sufficient to maintain any potential increase in postoperative thrombotic risk at an acceptable level in patients with UC undergoing operative intervention.

A characterization of anaerobic colonization and associated mucosal adaptations in the undiseased ileal pouch

INTRODUCTION

The resolution of pouchitis with metronidazole points to an anaerobic aetiology. Pouchitis is mainly seen in patients with ulcerative colitis pouches (UCP). We have recently found that sulphate reducing bacteria (SRB), a species of strict anaerobe, colonize UCP exclusively. Herein, we aimed to correlate levels of different bacterial species (including SRB) with mucosal inflammation and morphology.

METHODS

Following ethical approval, fresh faecal samples and mucosal biopsies were taken from 9 patients with UCP and 5 patients with familial adenomatous polyposis pouches (FAPP). For the purposes of comparison, faecal samples and mucosal biopsies were also taken from the stomas of 7 of the 9 patients with UC (UCS). Colonization by four types of strict anaerobes (SRB, Clostridium perfringens, Bifidobacteria and Bacteroides) as well as by three types of facultative anaerobes (Enterococci, Coliforms and Lactobacilli) was evaluated. Inflammatory scores and mucosal morphology were assessed histologically in a blinded fashion by a pathologist.

RESULTS

In general, strict anaerobes predominated over facultative in the UCP (P = 0.041). SRB were present in UCP exclusively. Even after exclusion of SRB from total bacterial counts, strict anaerobes still predominated. In the UCS, facultative anaerobes predominated. Strict and facultative anaerobes were present at similar levels in the FAPP. Enterococci were present at significantly reduced levels in the UCP when compared with the UCS (P = 0.031). When levels of SRB and other anaerobic species were individually correlated with mucosal inflammation and morphology, no trends were observed.

CONCLUSION

We have previously identified that SRB exclusively colonize UCP. In addition we have now identified a novel increase in the strict/facultative anaerobic ratio within the UCP compared to UCS. These stark differences in bacterial colonization, however, appear to have limited impact on mucosal inflammation or morphology.

Activated protein C attenuates acute ischaemia reperfusion injury in skeletal muscle

Activated protein C (APC) is an endogenous anti-coagulant with anti-inflammatory properties. The purpose of the present study was to evaluate the effects of activated protein C in the setting of skeletal muscle ischaemia reperfusion injury (IRI). IRI was induced in rats by applying rubber bands above the levels of the greater trochanters bilaterally for a period of 2h followed by 12h reperfusion. Treatment groups received either equal volumes of normal saline or activated protein C prior to tourniquet release. Following 12h reperfusion, muscle function was assessed electrophysiologically by electrical field stimulation. The animals were then sacrificed and skeletal muscle harvested for evaluation. Activated protein C significantly attenuated skeletal muscle reperfusion injury as shown by reduced myeloperoxidase content, wet to dry ratio and electrical properties of skeletal muscle. Further in vitro work was carried out on neutrophils isolated from healthy volunteers to determine the direct effect of APC on neutrophil function. The effects of APC on TNF-alpha stimulated neutrophils were examined by measuring CD18 expression as well as reactive oxygen species generation. The in vitro work demonstrated a reduction in CD18 expression and reactive oxygen species generation. We conclude that activated protein C may have a protective role in the setting of skeletal muscle ischaemia reperfusion injury and that this is in part mediated by a direct inhibitory effect on neutrophil activation.

Massive retroperitoneal ganglioneuroma presenting with small bowel obstruction 18 years following initial diagnosis

BACKGROUND

Ganglioneuroma is a rare tumour of neural crest origin, which arises from maturation of a neuroblastoma. While previously considered to be non-functioning, they are now known to be frequently endocrinologically active.

AIMS AND METHODS

We report a case of a massive retroperitoneal ganglioneuroma presenting with small bowel obstruction in an adult, 18 years after initial diagnosis. Urinary dopamine levels were elevated, but other catecholamines were within normal limits. This is the first report in the English-language literature of a retroperitoneal ganglioneuroma presenting with or causing intestinal obstruction. We also review the metabolic, radiological, and histological features of these tumours. Relevant publications were identified from a Medline search using the MeSH headings 'ganglioneuroma', 'retroperitoneal neoplasms' and 'intestinal obstruction', and also from the reference lists of retrieved articles.

CONCLUSIONS

Ganglioneuroma can grow to a massive size and present in a varied manner. It should be included in the differential diagnosis of any large retroperitoneal or mediastinal mass, including those causing bowel obstruction.