Wolfgang Feil

Technique and Long-Term Results of Intersphincteric Resection for Low Rectal Cancer

PURPOSEIntersphincteric resection of low rectal tumors is a surgical technique extending rectal resection into the intersphincteric space. This procedure is performed by a synchronous abdominoperineal approach with mesorectal excision and excision of the entire or part of the internal sphincter. This study was designed to evaluate the long-term results of this method focused on continence function and oncologic results.METHODSFrom 1984 to 2000, a total of 121 patients were operated on. The patients were evaluated prospectively according to a detailed preoperative and postoperative program.RESULTSOne hundred seventeen patients had rectal cancers, two had dysplastic villous adenomas, and two had carcinoid tumors. Cancers were staged according to the Dukes classification (Stage A in 41 percent, Stage B in 28 percent, and Stage C in 31 percent; median distance from the anal margin, 3 (range, 1–5) cm). Postoperative complications were: one death because of pulmonary embolism, 5.1 percent developed an anastomotic fistula, one patient had a fistula to the bladder requiring reoperation, one patient with ileus needed relaparotomy as well as one for intra-abdominal hemorrhage and a small-bowel fistula. One patient developed a fistula after closing the protective colostomy. Five patients developed late strictures of the coloanal anastomosis. After a median follow-up of 72.86 months, 5.3 percent of patients developed local recurrence. The continence status was satisfactory with 16 patients (13.7 percent) showing continence for solid stool only, and 1 patient (0.8 percent) showing episodes of incontinence. A transient problem was a high stool frequency after closure of the protective stoma.CONCLUSIONSIntersphincteric resection is a valuable procedure for sphincter-saving rectal surgery. We showed that this technique has satisfactory long-term results in functional and oncologic respects. An important prerequisite is a careful preoperative evaluation of local tumor spread with rectal magnetic resonance imaging excluding infiltration of the external sphincter.

Effects of extracellular pH on intracellular pH-regulation and growth in a human colon carcinoma cell-line

Mechanisms of intracellular pH (pHi) regulation seem to be involved in cellular growth and cell division. Little is known about how extracellular acidosis, known to occur in central regions of solid tumors, or alkaline conditions affect pHi regulation in colonic tumors. pHi changes in the colonic adenocarcinoma cell-line SW-620 were recorded by spectrofluorimetric monitoring of the pH-sensitive, fluorescent dye BCECF, and proliferative activity was assessed by [3H]thymidine uptake. Resting pHi in Hepes-buffered solution was 7.53 +/- 0.01 (n = 36). Both 1 mM amiloride and Na(+)-free solution inhibited pHi recovery from acidification and decreased pHi in resting cells. In HCO3-/CO2-buffered media resting pH1 was 7.42 +/- 0.01 (n = 36). Recovery from acidification was Na(+)-dependent, CI(-)-independent, and only partially blocked by 1 mM amiloride. In the presence of amiloride and 200 microM H2DIDS pHi recovery was completely inhibited. In Na(+)-free solution pHi decreased from 7.44 +/- 0.04 to 7.29 +/- 0.03 (n = 6) and no alkalinization was observed in CI(-)-free medium. Addition of 5 microM tributyltin bromide (an anion/OH-exchange ionophore) caused pHi to decrease from 7.43 +/- 0.05 to 7.17 +/- 0.08 (n = 5). The effects of pH0 on steady-state pHi, pHi recovery from acidification and proliferative activity after 48 h were investigated by changing buffer [CO2] and [HCO3-]. In general, increases in pH0 between 6.7 and 7.4 increased pHi recovery, steady-state pHi and growth rates. In summary, SW-620 cells have a resting pHi > 7.4 at 25 degrees C, which is higher than other intestinal cells. Acid extrusion in physiological bicarbonate media is accomplished by a pHi-sensitive Na+/H+ exchanger and a pHi-insensitive Na(+)-HCO3-cotransporter, both of which are operational in control cells at the resting pHi. No evidence for activity of a CI-/HCO3- exchanger was found in these cells, which could account for the high pHi observed and may explain why the cells continue to grow in acidic tumor environments.

Muscle transformation of the sartorius muscle in a canine model: Clinical impact for electrodynamic graciloplasty as a “neosphincter”

PURPOSE: Transformation of fast-twitching skeletal muscles to slow-twitching, slowly fatigable muscles have become of clinical interest in the recent past. Transposition and transformation of the gracilis muscle to use it as a substitute for a resected or defected anal sphincter (graciloplasty) has been reported as achieving promising results in the treatment of fecal incontinence caused by sphincter defects or following abdominoperineal anorectal excision for cancer. METHOD: This experimental study used a canine model and the sartorius muscle to evaluate the functional efficiency of two different configurations of the muscle loop to compare the presently applied transformation program (8 weeks) with a shorter (5 weeks) protocol. In six beagle dogs, both sartorius muscles were wrapped around two stomas, either in an alpha fashion or in the so-called split-sling technique. Muscle transformation was achieved by controlled neuromuscular stimulation either during eight (Program A) or five weeks (Program B). After completion of the transformation period, the function of the muscle slings was evaluated by manometry, and histomorphologic evaluation of the sartorius muscles was performed. RESULTS: It was shown that muscle transformation led to a slowly fatigable muscle that made it possible to perform continuos (tetanic) contraction, regardless of the configuration or the duration of the transformation. Median pressures created by these muscles also did not differ significantly. In accordance with these functional findings, the histologic evaluation showed the typical, significant increase of Type I fibers in both muscle slings and following both transformation protocols. Although the decrease of fast-twitching Type II fibers was more pronounced following the conventional (8 weeks) program, this finding did not influence the functional results. CONCLUSIONS: Results of our experiment indicate the possibility for using a shorter transformation protocol for transformation of the gracilis muscle during graciloplasty in the clinical setting. Furthermore, the efficacy and safety of the modified (split-sling) wrap technique was demonstrated.

Laminin stimuliert die schnelle Restitution der humanen Kolonschleimhaut nach Gallensäureschädigung in vitro

ZusammenfassungIn dieser Studie wurde der Einfluß von verschiedenen Faktoren auf die schnelle Restitution der humanen Kolonschleimhaut in vitro nach Schädigung mit Natriumdesoxycholat untersucht. Mit einer computergesteuerten Echtzeitmorphometrie wurde der zeitliche Ablauf der Restitution gemessen. Unmittelbar nach Schädigung waren 51% der Schleimhautoberfläche geschädigt, nach 5 h Restitution nur 26%. Kontinuierliche luminale Natriumde-soxycholatexposition während der Restitution oder kalziumfreie Nährlösung inhibierten die Restitution vollständig. Luminale Gabe von Antifibronektin-Antiserum oder von humanem Fibronektin zeigten keinen Einfluß auf die Restitution. Ein monoklonaler, gegen Laminin gerichteter Antikörper führte zu einer Restschädigung von 42%. Luminale Gabe von humanem Laminin stimulierte die schnelle Restitution, so daß nach 5 h nur mehr 8% der Schleimhautoberfläche geschädigt waren. Die transmukosale Potentialdifferenz und der Kurzschlußstrom wurden gemessen, der Widerstand berechnet. Nach luminaler Gallensäureexposition kam es zu einem Abfall der Potentialdifferenz, des Kurzschlußstroms und des Widerstandes. Die schnelle Restitution des humanen Kolons benötigt Kalzium, wird durch einen gegen Laminin gerichteten monoklonalen Antikörper gehemmt, durch Natriumdesoxycholat verhindert und weder durch Antifibronektin-Antiserum noch durch Fibronektin beeinflußt. Hingegen führt die luminale Gabe von Laminin zu einer Stimulation der schnellen Restitution.SummaryThis study investigated the influence of various factors on rapid epithelial restitution in the human colonic mucosa in vitro following superficial mucosal injury produced by luminal exposure to sodium deoxycholate. The morphologic time course of restitution was assessed with real-time morphometry. Immediately after injury 51% of the mucosal surface was damaged. Following undisturbed restitution 26% remained injured after 5 hours. Continuous luminal exposure to sodium deoxycholate during the restitution period or removal of calcium from the nutrient solution inhibited restitution completely. Luminal anti-fibronectin antiserum or purified fibronectin did not influence restitution. A monoclonal antibody against laminin caused a residual damage of 42% whereas luminal purified laminin accelerated rapid epithelial restitution significantly as only 8% of the mucosal surface were damaged after 5 hours. Transmucosal potential difference and short-circuit current were measured, resistance was calculated. Bile salt injury produced a drop of potential difference, short-circuit current and resistance. These results show that rapid epithelial restitution of the human colon in vitro requires calcium, is impaired by anti-laminin antibody, completely inhibited by sodium deoxycholate, but unaffected by anti-fibronectin antiserum and fibronectin. Luminal addition of laminin accelerates rapid epithelial restitution.

Metabolic base production and mucosal vulnerability during acid inhibition in a mammalian stomach in vitro.

Acid inhibition increases gastric mucosal susceptibility to damage by luminal acid. This might be due to reduced metabolic CO2 and bicarbonate whereas, during normal acid, secretion cytoprotective CO2/HCO3- production parallels acid production. Metabolic activity and mucosal damage caused by luminal acid perfusion was determined in anin vitro mouse stomach, with and without acid inhibition, and at 0%, 1%, or 5% serosal CO2 supply. Without acid inhibition there was no mucosal damage at any level of serosal CO2/HCO3- supply. Acid inhibition reduced metabolic CO2 production by 29% (P<0.004) and resulted in microscopic damage to 55% of the mucosal area and perforation in four of five stomachs (P<0.05). Although, 1% CO2 supply completely replaced the reduction in metabolic CO2, it did not protect against mucosal damage. Overreplacement by 5% serosal CO2/HCO3- was required to prevent damage. There was no correlation between luminal CO2/HCO3- output and mucosal damage. The protection by endogenous or exogenous CO2/HCO3- appears to act intracellularly rather than by intragastric or intercellular neutralization.

Bedeutung des HCO3-CO2-Puffersystems für die Homöostase des intrazellulären pH in SW620-Kolonkarzinomzellen

ZusammenfassungHintergrund: Solide Tumoren weisen azidotische Regionen mit durchschnittlichen extrazellulären pH Werten (pHo) von 6,9 bis 7,0 (Normalgewebe: 7,4 bis 7,5) auf. In humanen SW620-Kolonkarzinomzellen konnten in einer früheren Arbeit ein Na/H-Austauscher sowie ein Na/HCO3-Kotransporter als Säureextrusoren nachgewiesen werden, ein Cl/HCO3-Austauscher wurde im Gegensatz zu anderen Tumorlinien nicht gefunden. Diese Studie untersucht die Auswirkungen unterschiedlicher extrazellulärer pH-Bedingungen auf die intrazelluläre pH-Regulation am Modell der SW620-Kolonkarzinomzellen, durch Variation des CO2-Partialdrucks und der HCO3-Konzentration der Inkubationslösungen. Methodik: SW620-Zellen wurden in HEPES-gepufferter Lösung (pH = 7,4; 25 °C) mit dem pH-sensitiven Fluoreszenzfarbstoff BCECF beladen und pHi-Veränderungen mittels einer computergesteuerten Spektrofluorimetrieanlage aufgezeichnet. Durch Kombination von 5, 15, 25 und 35 mM HCO3 mit 2,5, 5 und 15 Vol.% CO2 (Rest-Vol.% O2) Begasung wurden 12 Versuchsanordnungen mit unterschiedlichem pHo (pHo = 6,30 bis 7,81) gebildet. Ergebnisse: Der Ruhe-pHi in HEPES-Lösung betrug 7,52 ± 0,01 (n = 72). Nach Wechsel zu HCO3/CO2-Medium kam es zu einer Ansäuerung von 0,25 bis 0,77 pH-Einheiten. 5% CO2/5 mM HCO3 führte nach einer Ruheperiode von 15 min zu einer pHi-Verschiebung um ≥ 0,2 Einheiten in den sauren Bereich und 2,5% CO2/35 mM HCO3 zu einer pHi-Verschiebung um ≥ 0,2 Einheiten in den alkalischen Bereich gegenüber dem Standard-Ruhe-pHi (7,39 bei 5% CO2/25 mM HCO3). Bei 15% CO2/5 mM HCO3 (pHo = 6,26) konnte keine Rückregulation beobachtet werden. Schlußfolgerungen: Die Ergebnisse im SW620-In-vitro-Modell zeigen, daß extrazelluläre Abweichungen von Standard-CO2- und-Bikarbonatbedingungen zu Störungen der intrazellulären pH-Homöostase führen. Das Ausmaß der intrazellulären Ansäuerung war von der CO2-Spannung abhängig, die H-Extrusionsraten wurden durch den extrazellulären pH bestimmt. Diese Resultate demonstrieren die prinzipielle Möglichkeit, eine selektive Beeinträchtigung der intrazellulären pH-Homöostase und damit der Zellfunktion von Tumorzellen durch Veränderung des extrazellulären pH zu erzielen.SummaryBackground: Extracellular pH (pHo) in malignant tumors often reaches levels below 7.0 (mean values 0.5 pH units lower compared to normal tissues). This study was designed to investigate regulation and maintainance of intracellular pH (pHi) of a human colonic carcinoma derived cell-line (SW620) under different extracellular pH conditions by modulating CO2-tensions and bicarbonate concentrations. Previously we characterized a Na/H exchanger and a Na/HCO3-cotransporter to account for acid extrusion in these cells, whereas no evidence of the presence of a Cl/HCO3 exchanger was found. Methods: pHi changes of cells were recorded by spectrofluorimetric monitoring of the pH-sensitive, fluorescent dye BCECF. Dye loaded cells were incubated in air-equilibrated HEPES-buffered solution (pH = 7.4, 25 °C), then bathing solutions were switched to HCO3/CO2-buffered media to simulate different conditions. 12 groups were designed by matching bicarbonate concentrations of 5, 15, 25, and 35 mM with 2.5, 5, or 15% CO2 resulting in different pH (pHo = 6.30 to 7.81). Results: Steady state pHi of SW620 cells in HEPES-buffered solution was 7.52 ± 0.01 (n = 72). When cells were exposed to HCO3/CO2-buffered solutions with different pHo they rapidly acidified by 0.25 to 0.77 pH units. After a period of 15 min 5% CO2/5 mM HCO3 led to a pHi-change of ≥ 0.2 pHi units towards acidic pHi and 2.5% CO2/35 mM HCO3 to a pHi-change of ≥ 0.2 units towards alkaline pHi, compared to standard resting pHi (7.39 at 5% CO2/25 mM HCO3). At 15% CO2/5 mM HCO3 (pHo = 6.26) no pHi-recovery was observed. Conclusions: Deviations from standard extracellular CO2 and HCO3 concentrations provide a challenge to cellular homeostasis. Cytoplasmic acidification was dependent on CO2-tensions, H-extrusion rates were determined by extracellular pH (pHo). Manipulation of pHi-regulation in tumor cells by varying extracellular pH could lead to intracellular conditions which might affect cell-function and therefore contribute to anti-tumor strategies.