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Consensus abstract Background The management of primary rectal cancer beyond total mesorectal excision planes (PRC-bTME) and recurrent rectal cancer (RRC) is challenging. There is global variation in standards and no guidelines exist. To achieve cure most patients require extended, multivisceral, exenterative surgery, beyond conventional total mesorectal excision planes. The aim of the Beyond TME Group was to achieve consensus on the definitions and principles of management, and to identify areas of research priority. Methods Delphi methodology was used to achieve consensus. The Group consisted of invited experts from surgery, radiology, oncology and pathology. The process included two international dedicated discussion conferences, formal feedback, three rounds of editing and two rounds of anonymized web-based voting. Consensus was achieved with more than 80 per cent agreement; less than 80 per cent agreement indicated low consensus. During conferences held in September 2011 and March 2012, open discussion took place on areas in which there is a low level of consensus. Results The final consensus document included 51 voted statements, making recommendations on ten key areas of PRC-bTME and RRC. Consensus agreement was achieved on the recommendations of 49 statements, with 34 achieving consensus in over 95 per cent. The lowest level of consensus obtained was 76 per cent. There was clear identification of the need for referral to a specialist multidisciplinary team for diagnosis, assessment and further management. Conclusion The consensus process has provided guidance for the management of patients with PRC-bTME or RRC, taking into account global variations in surgical techniques and technology. It has further identified areas of research priority.

Two types of procedure may be indicated in incurable patients. The first is palliative, in which the goal of intervention is relief of symptoms. The second type is supportive, where the procedure is a technical intervention done as part of a multidisciplinary treatment plan. The most minimally invasive but effective procedure is chosen. Procedures are categorized by the type of symptom the procedure is intended to relieve. This article emphasizes the principles involved in patient selection and outcome assessment in order to identify areas where more research is needed.

Members of the matrix metalloproteinase family of enzymes degrade specific components of the extracellular matrix. MMP-9 is a type IV/V collagenase necessary for normal osteogenesis and is increased in inflammatory and neoplastic conditions. In such destructive diseases as emphysema and arthritis, and in epithelial cancers, MMP-9 is produced by cells of the monocyte lineage. Fetuin, a prominent serum glycoprotein, binds to and inactivates TGF-beta family members and through this mechanism regulates osteogenesis (Binkert et al., 1999, J Biol Chem 274:28514-28520.). We studied the effects of TGF-beta1 and fetuin on proMMP-9 release by the human monocyte line THP-1. Exogenous TGF-beta1 stimulated proMMP-9 release by THP-1 cells, with half-maximal stimulation at approximately 0.01 ng/ml TGF-beta1. Human fetuin (0.5-2 microM) partially inhibited this stimulation. Human fetuin alone stimulated THP-1 monocyte proMMP-9 release, with half maximal stimulation at approximately 0.25 microM fetuin. Neutralizing antibody specific for TGF-beta1 also stimulated proMMP-9 release, suggesting that endogenously-derived TGF-beta1 has an inhibitory effect. In freshly isolated human peripheral blood monocytes, fetuin stimulated proMMP-9 release with a dose-response curve similar to that observed in THP-1 cells. Human fetuin also activated proMMP-9 present in THP-1 conditioned medium. Taken together, these data suggest that under physiological conditions, fetuin facilitates matrix degradation by monocyte-derived MMP-9, both by opposing the autocrine inhibitory effect of endogenous TGF-beta1 on proMMP-9 release, and by activating proMMP-9 in the pericellular milieu. Conversely, fetuin may limit the stimulation of monocyte proMMP-9 release by high levels of exogenous TGF-beta1. Such modulation could prove important under pathological conditions where TGF-beta1 derived from paracrine sources is abundant, such as in epithelial malignancies.

Maintenance of cytoplasmic pH (pHi) within a narrow physiological range is critical to optimal cell function. Monocytes and macrophages (Møs) actively regulate their pHi through three distinct plasma membrane ion transport systems: (1) Na+/H+ exchange; (2) Na(+)-dependent anion exchange; and (3) vacuolar-type H+ ATPases. Alterations in the functional state of monocytes and Møs have been linked to changes in pHi and/or its regulation by these ion transport systems. Differentiation, proliferation, and activation of Møs in response to a variety of agents are associated with increased Na+/H+ exchange. The resultant cytoplasmic alkalinization typically observed in HCO3(-)-free media likely plays a permissive, rather than a triggering, role in mediating Mø response to most of these agents. Prevention of cytoplasmic acidification is essential during Mø activation, when production of metabolic acid increases. This is of particular importance within the in vivo microenvironment of an abscess or tumour, where pHi is further threatened by the low extracellular pH (pHo) which typically prevails. At low pHo, H+ ATPase-mediated H+ extrusion plays a critical role in maintenance of pHi, preserving the ability of Møs to generate a respiratory burst. The requirement for maintenance of pHi within a range conducive to efficient Mø function may explain why Møs have acquired a variety of parallel systems for pHi regulation.

The advent of high-resolution imaging has allowed earlier diagnosis of pyogenic liver abscess. Because radiologically guided percutaneous drainage (PCD) of liver abscesses is controversial, the authors studied 40 patients with liver abscess admitted to the Toronto Hospital between 1982 and 1987 to determine the role of PCD versus operative drainage (OD). The diagnosis of pyogenic liver abscess was made at autopsy (4 patients), at laparotomy (6) or by radiologically guided aspiration of pus (30). Ultrasonography and computed tomography were highly sensitive (85% and 96% respectively) in detecting liver abscess. Of the 36 patients treated for liver abscess all received antibiotics intravenously; 31 also underwent a drainage procedure. Treatment with antibiotics alone was associated with a success rate of 80% and a death rate of 20%. The success rate for those who had PCD was 75% with a death rate of 13%; 2 patients in this group of 16 subsequently required OD for cure. In the 15 patients initially treated with OD, success and death rates were 87% and 13% respectively. For solitary abscesses, success rates wer comparable for PCD and OD (86% and 90% respectively). For unilobar multiple abscesses the success rate was 100% for both PCD and OD, but for bilobar multiple abscesses the rates were only 40% and 67% respectively. Complication rates were similar for both methods of drainage. The authors conclude that pyogenic liver abscess can now be safely and efficaciously managed with a combination of antibiotics and PCD.

Within the acidic milieu of an abscess or tumor, macrophages must be able to maintain their cytoplasmic pH (pHi) close to the physiologic range to ensure optimal cell function. Our recent studies have demonstrated that a proton-extrusion mechanism with the characteristics of an H+ adenosine triphosphatase mediates pHi recovery in acid-loaded macrophages. These studies were designed to examine the role of these H+ pumps in maintaining cell function in an acidic extracellular environment. Peritoneal macrophages were tested for superoxide production in response to phorbol myristate acetate at either physiologic or acidic extracellular pH (pHo; 7.35 or 6.70, respectively). pHi was measured with the fluorescent dye 2',7'-biscarboxy-ethyl-5(6)-carboxy-fluorescein. Bafilomycin A1, a specific H+ adenosine triphosphatase inhibitor, was used to examine the contribution of the H+ pump to pHi regulation and cell function. At pHo 7.35, bafilomycin A1 had no effect on pHi or phorbol myristate acetate-stimulated superoxide production. However, at pHo 6.70, bafilomycin A1 reduced pHi to 6.61 +/- 0.01 versus 6.79 +/- 0.01 in control cells (p less than 0.001) and caused a concomitant reduction in superoxide production to 4.8 +/- 1.2 versus 13.0 +/- 1.2 nmol/10(6) cells/40 min in control cells (p less than 0.001). To determine whether the observed reduction in superoxide formation was the result of the pHi reduction, superoxide production was measured in cells whose pHi was pharmacologically clamped at various levels according to the K+/nigericin method. Lowering pHi from 6.80 to 6.60 caused a significant reduction in superoxide production from 13.1 +/- 1.8 to 7.5 +/- 0.9 nmol/10(6) cells/40 min (p less than 0.01). Thus H+ extrusion pumps are important to maintenance of macrophage pHi at low pHo, permitting continued superoxide production under these conditions. By keeping pHi close to the physiologic range, these pumps serve to optimize cell function in an acidic extracellular environment.

An Na(+)- and HCO3(-)-independent mechanism of cytoplasmic pH (pHi) recovery was previously demonstrated in acid-loaded macrophages (Swallow, C. J., Grinstein, S., and Rotstein, O. D. (1988) J. Biol. Chem. 263, 19558-19563). Acid extrusion was found to be ATP-dependent and sensitive to N-ethylmaleimide and N,N'-dicyclohexylcarbodiimide, suggesting involvement of an H(+)-pumping ATPase. In this report, the properties and mode of activation of this putative pump were studied in detail. In acid-loaded cells, pHi recovery, measured using a fluorescent probe, was found to be insensitive to azide or oligomycin, which are inhibitors of F0F1 (mitochondrial) H(+)-ATPases, and to vanadate, an inhibitor of E1E2-type ATPases. Instead, the recovery was sensitive to the vacuolar type H(+)-ATPase inhibitors 7-chloro-4-nitrobenz-2-oxa-1,3-diazole, p-chloromercuribenzenesulfonic acid, and bafilomycin A1. Using the fluorescent probes bisoxonol and 3,3'-dipropylthiodicarbocyanide iodide to measure the membrane potential of intact cells, acid loading of macrophages was shown to result in an N,N'-dicyclohexylcarbodiimide-sensitive hyperpolarization of approximately 15 mV. This hyperpolarization was not inhibited by charybdotoxin, suggesting that it was not due to efflux of K+ through Ca2(+)-activated K+ channels, but may instead be due to electrogenic pumping of protons across the plasma membrane. This was consistent with the partial dependence of the Na(+)- and HCO3(-)-independent pHi recovery on the presence of intracellular Cl-. As in vacuolar membranes, Cl- appears to act as a counterion to H+, preserving electroneutrality and thus facilitating pHi recovery. In acid-loaded urinary epithelial cells, activation of H+ pumping occurs by exocytic insertion of intracellular (vacuolar) H(+)-ATPases into the plasma membrane. In this system, exocytosis is triggered by an associated increase in the cytoplasmic free Ca2+ concentration and is microtubule-dependent. We determined whether an analogous process exists in macrophages. Acid loading of macrophages induced an approximately 120 nM increase in cytoplasmic free Ca2+ concentration due to mobilization of Ca2+ from an intracellular source. However, preventing this increase by preloading macrophages with bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid did not inhibit the Na+ and HCO3(-)-independent pHi recovery, neither was the recovery inhibited by microtubular disruption using 0.1 mM colchicine. Furthermore, cytoplasmic acid loading did not cause a detectable release of secretory granular, endosomal, or lysosomal contents, suggesting that activation of H+ pumping at the cell surface is not mediated by exocytic fusion of these compartments with the plasma membrane. Taken together, these data suggest that H(+)-ATPases are constitutively present in the macrophage plasma membrane.(ABSTRACT TRUNCATED AT 400 WORDS)

Cytoplasmic pH (pHi) regulation was studied in thioglycolate-elicited murine macrophages using fluorescent probes. Acid-loaded macrophages regained normal pHi by extrusion of H+ equivalents across the plasma membrane. A fraction of this recovery was due to Na+/H+ exchange, as evidenced by its partial Na+ dependence and amiloride sensitivity. The residual, Na+-independent pHi recovery (approximately 50% of the total) persisted in the nominal absence of HCO3- and was insensitive to disulfonic stilbenes, ruling out mediation by anion exchange. In contrast, intracellular alkalinization and H+ extrusion from the cells were inhibited by N-ethylmaleimide, by N,N'-dicyclohexylcarbodiimide or by prior depletion of intracellular ATP. These observations are consistent with the existence of a H+-pumping ATPase in the plasma membrane of macrophages. The mechanism of activation of the ATP-dependent H+ extrusion process was also investigated. In other systems, Ca2+ mobilization has been suggested to signal an exocytic insertion of H+ pumps into the plasma membrane. Acid loading of macrophages was accompanied by an elevation of the cytosolic Ca2+ concentration ([Ca2+]i), measured using indo-1. These results are consistent with a role for Ca2+ mobilization in the activation of H+ extrusion.