Technology and clinical application of ultrasonic dissection

The implementation of UltraCision (The Harmonic Scalpel) can be seen as a milestone in the development of surgery. Ultrasound is now used for tissue cutting and/or simultaneous vessel sealing and transection. No electric current passes through the patient. Thus the typical complications associated with electrocautery can be avoided. This technology was primarily developed for videoscopic surgery and then successfully transferred to all branches of open surgery. The clean and blood-saving dissection technology and the ability to dissect very close to sensitive structures in oncological surgery are highly beneficial for patients. The development of new blades and multifunctional shears has further enhanced both practicability and ergonomics. UltraCision can now be used for the complete surgical spectrum, both in open and in laparoscopic surgery.

MR imaging for the preoperative planning of sphincter-saving surgery for tumors of the lower third of the rectum: use of intravenous and endorectal contrast materials

PURPOSE

To evaluate the value of magnetic resonance (MR) imaging with a flexible surface coil in predicting the resectability of tumors in the lower rectum and the feasibility of sphincteral salvage.

MATERIALS AND METHODS

In a prospective study, 61 patients with histologically proved primary adenocarcinoma of the lower or middle third of the rectum (<12 cm from the pectinate line) were examined at double-contrast-material-enhanced MR imaging with a circular polarized flexible surface coil.

RESULTS

Assessment of anal sphincteral infiltration at MR imaging was excellent, with a specificity of 98% and a sensitivity of 100%. In the determination of tumor infiltration into adjacent organs (T4), the specificity was 100%, and the sensitivity was 90%, with surgical and histologic findings as the standards. While MR imaging showed negative nodes in 40 patients (stage N0 at MR imaging), histologic examination showed negative nodes in 27 patients and positive nodes in 34. At MR imaging, sensitivity was 68%, and specificity was 24%.

CONCLUSION

While preoperative staging at MR imaging according to the TNM system still has limited value and accuracy, MR imaging provides the surgeon with valuable information regarding the presence of sphincteral invasion and the surrounding structures in patients with cancers in the lower third of the rectum.

Bacteroides fragilis toxin 2 damages human colonic mucosa in vitro

BACKGROUND

Strains of Bacteroides fragilis producing a 20 kDa protein toxin (B fragilis toxin (BFT) or fragilysin) are associated with diarrhoea in animals and humans. Although in vitro results indicate that BFT damages intestinal epithelial cells in culture, the effects of BFT on native human colon are not known.

AIMS

To examine the electrophysiological and morphological effects of purified BFT-2 on human colonic mucosa in vitro.

METHODS

For resistance (R) measurements, colonic mucosa mounted in Ussing chambers was exposed to luminal or serosal BFT-2 (1.25-10 nM) and after four hours morphological damage was measured on haematoxylin and eosin stained sections using morphometry. F actin distribution was assessed using confocal microscopy.

RESULTS

Serosal BFT-2 for four hours was four-, two-, seven-, and threefold more potent than luminal BFT-2 in decreasing resistance, increasing epithelial 3H-mannitol permeability, and damaging crypt and surface colonocytes, respectively (p<0.05). Confocal microscopy showed reduced colonocyte F actin staining intensity after exposure to BFT-2.

CONCLUSIONS

BFT-2 increases human colonic permeability and damages human colonic epithelial cells in vitro. These effects may be important in the development of diarrhoea and intestinal inflammation caused by B fragilis in vivo.

[Anal sphincter restoration using dynamic graciloplasty--results of 50 patients]

During the period from 1992 to 1998, 50 patients underwent anal sphincter restoration by dynamic graciloplasty for primary (n = 26) or secondary (n = 6) total anorectal reconstruction (TAR) following abdominoperineal rectal resection (APR) or acquired (n = 9) or congenital (n = 9) fecal incontinence, respectively. Forty-seven patients were operated on by a single-stage procedure using a modified technique for the muscle wrap ("split sling"). Muscle fiber transformation by controlled stimulation was achieved at the beginning of the learning curve within 8 weeks and in the meantime within 4 weeks. Rectal injury (n = 10) turned out to be the most serious postoperative complication and was observed mainly in patients following TAR (n = 8). As the most prominent functional problem constipation in patients following TAR hampered the postoperative functional result; however, this was overcome by regular enemas. An improvement in the continence status was observed in 80% of the patients treated for fecal incontinence, and following APR 66% of the patients had acceptable results without a permanent colostomy.

Restoration of anal sphincter function by single-stage dynamic graciloplasty with a modified (split sling) technique

BACKGROUND

Controlled muscle fiber conversion by electrostimulation makes transformation of fast twitching type II muscle fibers to slow twitching type I fibers possible, which gives skeletal muscles the capacity for tetanic contraction. This phenomenon has been recently applied in the so-called "dynamic graciloplasty" to restore function of an insufficient or excised anal sphincter. This paper describes our results with this method in patients with fecal incontinence or following an abdomino-perineal resection (APR) of the anorectum.

METHODS

From April 1992 through April 1997, 28 patients (12 women and 16 men) were treated by dynamic graciloplasty. The median age was 53.5 years (range 16 to 79). Indications were as follows: APR + synchronous restoration of the excised sphincter by graciloplasty (n = 12); total anorectal reconstruction (TAR) following APR in the past (n = 6); Patients with acquired fecal incontinence (n = 4); and Congenital atresia (n = 6). Muscle transposition, implantation of stimulation electrodes and pulse generator were done as a single-stage procedure, the "neosphincter" was wrapped in a modified technique (split-sling technique). Muscle transformation was performed by controlled neuromuscular stimulation during 8 weeks (from 1992 to 1995) and 4 weeks (since 1996), respectively.

RESULTS

No postoperative mortality (90 days) was observed in either group. In our early experience, rectal injury occurred in 4 patients as the most prominent complication. Evaluation of the functional outcome showed the best results in patients operated either for congenital of acquired incontinence who achieved a continence for solids and liquids or solids alone, respectively (1 or 2 according to Williams' score) in 90%, while patients following APR showed a satisfying outcome (continence for solids and liquids, solids alone or with occasional episodes for liquids) in only 55.5%. In patients following APR, defecation disorders turned out to be the most prominent functional problem and had to be treated by enemas.

CONCLUSION

In this series, we have been able to perform dynamic graciloplasty as a one-stage procedure using a modified muscle wrap (split-sling-technique) thus reducing the time period until continence could be achieved to 7 weeks. We found the appropriate tension of the muscle wrap essential to prevent direct injury to the rectum as it was seen in our early experience. For this reason, we have introduced a modified device to perform intraoperative anal manometry and to measure pressures created by the neosphincter objectively.

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 has 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) have 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.

Epidermal growth factor attenuates Clostridium difficile toxin A- and B-induced damage of human colonic mucosa

Epidermal growth factor (EGF) exhibits a cytoprotective effect on gastrointestinal epithelia via a receptor-mediated mechanism. We investigated the effect of EGF on Clostridium difficile toxin A (TxA)- and toxin B (TxB)-induced damage of human colon. Ussing-chambered colonic mucosa was exposed serosally to EGF before and during luminal exposure to TxA and TxB. Resistance was calculated from potential difference and short-circuit current. Epithelial damage was assessed by light microscopy and alteration of F-actin by fluoresceinated phalloidin. Luminal exposure of colonic strips to TxA and TxB caused a time- and dose-dependent decrease in electrical resistance, necrosis and dehiscence of colonocytes, and disruption and condensation of enterocyte F-actin. These effects were inhibited by prior, but not simultaneous, serosal application of EGF (20 nM). Administration of the tyrosine kinase inhibitor genistein (10(-6) M) inhibited the protective effects of EGF. We conclude that EGF protects against TxA and TxB probably by stabilizing the cytoskeleton, the main target of these toxins.

Effect of growth factors on epithelial restitution of human colonic mucosa in vitro

BACKGROUND

Epithelial restitution enables resurfacing of epithelial discontinuities by enterocyte migration. This study investigated the effect of basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF-1), and epidermal growth factor (EGF) on restitution of human colonic mucosa in vitro.

METHODS

After base-line incubation human colonic mucosal strips, mounted in Ussing chambers, were luminally exposed to 0.5 mM sodium deoxycholate (NaDOC) for 10 min. Thereafter tissues were incubated with buffer alone or luminal buffer containing various concentrations of bFGF, IGF-1, and EGF for 3 h. Resistance (R) was calculated from potential difference (PD) and short-circuit current (Isc). All tissues were processed for light microscopy. Extent of damage was measured by morphometry.

RESULTS

Luminal 0.5 mM NaDOC for 10 min caused R to drop by 43% (n = 4; P < 0.05). Compared with controls 50 ng/ml EGF induced an approximately 30% R increase until the end of the experiments (P < 0.05, n = 4, paired). Ten minutes after injury 50.2 +/- 4% of the mucosa was damaged (n = 6), and after 3 h damage was significantly reduced by EGF (17.2 +/- 3% versus 31.7 +/- 4%, 50 ng/ml EGF versus controls) (P < 0.05, n = 6 per group). Histology showed that EGF stimulated enterocyte migration over the basal lamina. Various doses of bFGF and IGF-1 did not impair restitution when compared with controls.

CONCLUSION

In contrast to bFGF and IGF-1, EGF was shown to promote epithelial restitution of human colonic mucosa in vitro.

Laminin stimulates rapid epithelial restitution of rabbit duodenal mucosa in vitro

BACKGROUND

This study investigated the effect of the basal lamina constituents fibronectin, collagen IV, and laminin on epithelial restitution of rabbit duodenum in vitro.

METHODS

Rabbit duodenal mucosal sheets were mounted in Ussing chambers, luminally exposed to 10 mM HCI for 10 min, and incubated with buffer or luminal buffer containing 25-100 micrograms/ml of collagen IV, fibronectin, laminin, or polyclonal antisera directed against these proteins (diluted 1:50-1:20) for 3 h. Resistance was calculated from potential difference and short-circuit current. Mucosal damage was assessed by morphometry on hematoxylin- and eosin-stained sections.

RESULTS

Acid exposure caused a 40% drop in resistance (119 +/- 5 versus 71 +/- 5 Ohm.cm2 before versus after injury; P < 0.05, n = 6) and mucosal damage of 58 +/- 4% (n = 6). Three hours after injury resistance was 102 +/- 6, 117 +/- 4, and 48 +/- 5 Ohm.cm2 in the control, laminin, and anti-laminin groups, respectively. Furthermore, 36 +/- 2%, 16 +/- 2%, and 64 +/- 5% of the mucosa was damaged in the control, laminin, and anti-laminin groups, respectively, 3 h after injury (P < 0.05 versus controls). Laminin promoted epithelial wound closure by stimulation of enterocyte migration, which was inhibited by anti-laminin. Fibronectin, collagen IV, anti-fibronectin, and anti-collagen IV did not impair restitution.

CONCLUSION

Our results show that laminin promotes electrophysiologic restoration and epithelial restitution of rabbit duodenum in vitro. We therefore suggest that laminin plays an important part in the orchestration of epithelial integrity and barrier function.

Epidermal growth factor promotes rapid response to epithelial injury in rabbit duodenum in vitro

BACKGROUND & AIMS

Growth factors are mainly involved in the regulation of intestinal epithelial barrier function. This study investigated the effect of epidermal growth factor (EGF) and insulin-like growth factor 1 (IGF-1) on epithelial restitution of rabbit duodenum in vitro.

METHODS

Rabbit duodenal mucosal strips mounted in an Ussing chamber were luminally exposed to 10 mmol/L HCl for 10 minutes and then incubated with buffer alone or luminal buffer containing various concentrations of EGF and IGF-1 for 3 hours. Resistance was calculated from potential difference and short-circuit current. Damage was assessed by morphometry on H&E-stained sections.

RESULTS

HCl caused resistance to decrease from 112 +/- 2 to 51 +/- 4 ohms x cm2 10 minutes after injury (n = 6; P < 0.05). Postinjury treatment with 25 or 50 ng/mL luminal EGF for 3 hours stimulated resistance to recover to 94 +/- 3 and 104 +/- 3 ohms x cm2, respectively, vs. 81 +/- 3 omega x cm2 in controls (P < 0.05). Ten minutes after injury, 62% of the mucosa was damaged; 3 hours after injury, damage was reduced to 24% +/- 1.09% and 10% +/- 1.42% in the 25 and 50 ng/mL EGF group, respectively, vs. 38% +/- 0.93% in controls (n = 6 per group). EGF stimulated enterocyte migration. IGF-1 did not impair epithelial restitution.

CONCLUSIONS

EGF, but not IGF-1, promoted epithelial restitution of rabbit duodenum in vitro.

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.

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 an in 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.

Clostridium difficile toxin B is more potent than toxin A in damaging human colonic epithelium in vitro

Toxin A but not toxin B, appears to mediate intestinal damage in animal models of Clostridium difficile enteritis. The purpose of this study was to investigate the electrophysiologic and morphologic effects of purified C. difficile toxins A and B on human colonic mucosa in Ussing chambers. Luminal exposure of tissues to 16-65 nM of toxin A and 0.2-29 nM of toxin B for 5 h caused dose-dependent epithelial damage. Potential difference, short-circuit current and resistance decreased by 76, 58, and 46%, respectively, with 32 nM of toxin A and by 76, 55, and 47%, respectively, with 3 nM of toxin B, when compared with baseline (P < 0.05). 3 nM of toxin A did not cause electrophysiologic changes. Permeability to [3H]mannitol increased 16-fold after exposure to 32 nM of toxin A and to 3 nM of toxin B when compared with controls (P < 0.05). Light and scanning electron microscopy after exposure to either toxin revealed patchy damage and exfoliation of superficial epithelial cells, while crypt epithelium remained intact. Fluorescent microscopy of phalloidin-stained sections showed that both toxins caused disruption and condensation of cellular F-actin. Our results demonstrate that the human colon is approximately 10 times more sensitive to the damaging effects of toxin B than toxin A, suggesting that toxin B may be more important than toxin A in the pathogenesis of C. difficile colitis in man.

Intracellular pH regulation of human colonic crypt cells

In order to investigate the regulation of intracellular pH (pHi) in freshly isolated human colonocytes, we have used a newly developed technique for the rapid isolation and covalent attachment of these cells to glass surfaces and microspectrofluorimetric measurement of the pH-sensitive fluorescence of 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-loaded specimens in a perfusion chamber (37 degrees C). In N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic-acid-(HEPES)-buffered Ringer solution (HBS) a baseline pHi of 7.35 +/- 0.03 (mean +/- SD; n = 42) was found for human colonocytes and in HBS, NH4Cl-prepulse-induced intracellular acidification in colonocytes is reversed rapidly by the ubiquitous amiloride-sensitive (1 mmol/l) Na+/H+ exchanger. Switching from HBS to HCO(3-)-buffered solution (BBS) led to a transient intracellular acification (7.29 +/- 0.09), followed by a recovery to a final resting pHi of 7.43 +/- 0.03. One-third of the acid extrusion in BBS is amiloridesensitive; the remaining two-thirds are caused by the dihydroderivative of 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (H2DIDS)-sensitive HCO(3-)-dependent mechanisms. The functional activity of an acid-extruding Na+/HCO3- cotransporter in human colonocytes was observed in response to the reintroduction of Na+ into amiloride-containing Na+/Cl(-)-free BBS. In addition, the mechanism leading to alkalinization (7.56 +/- 0.05) in Cl(-)-free BBS was identified as Na(+)-dependent Cl-/HCO3- exchange, by its H2DIDS sensitivity and the specific requirement for Cl- and Na+. The intrinsic buffering capacity (beta i) of the human colonocytes was calculated from pH changes induced by sequential NH4Cl-loading steps during blockage of acid/base transporters.(ABSTRACT TRUNCATED AT 250 WORDS)

The electrically stimulated (dynamic) graciloplasty for faecal incontinence--first experiences with a modified muscle sling

Continence following the gracilis stimulated neosphincter reconstruction after total rectal excision is inferior to that obtained in the presence of an intact anal canal. We describe a modification of the alpha loop in which the tendon is brought through the belly of the gracilis muscle. The results in three patients are presented.

The multidrug-resistance modifiers verapamil, cyclosporine A and tamoxifen induce an intracellular acidification in colon carcinoma cell lines in vitro

In this study we have investigated the effects of the multidrug-resistance (MDR) modifiers verapamil (VPM), cyclosporin A (CsA) and tamoxifen (TMX) on the intracellular pH(pHi) of four colon carcinoma-derived cell lines with low P-glycoprotein expression (CaCo-2, HT-29, SW 620 and SW 480). Addition of VPM (1 mu M), CsA (1 microgram/ml) or TMX (2 microM) in HEPES- or bicarbonate/CO2-buffered Ringer's solution was followed by dose-dependent and reversible decreases of the pHi (0.1-0.3 units) of all cell lines, as measured ratiometrically by the changes in the pH-dependent fluorescence of bis(carboxyethyl)carboxyfluorescein (BCECF). Testing the effects of the resistance modifiers on the Na+/H+ antiporter and bicarbonate trans-porters under appropriate buffer conditions and addition of inhibitors (amiloride, DIDS) revealed that the chemomodulator-induced acidification does not interfere with the function of these major pHi-regulating acid-base transporters. The induction of changes in pHi shows no correlation with MDR-reversing activity of the drugs and our data do not support the P-gp-inhibition-mediated accumulation of acidic substrates as underlying mechanism. In addition to the P-gp-directed MDR-reversal, chemomodulator-induced intracellular acidification may enhance the chemosensitivity of the cells especially under alkaline extracellular conditions, and contribute to the decreased efficacy of MDR-modifiers in acidic extracellular environments and to the chemosensitising effect of VPM in P-gp-negative cell lines.

[2 cases of life threatening gastrointestinal hemorrhage from Meckel's diverticulum]

Meckel's diverticulum is one of the commonest congenital anomalies of the gastrointestinal tract. Two cases requiring emergency laparotomy due to massive gastrointestinal bleeding are presented. Only at laparotomy the correct diagnosis was established. In the first case a segment of small bowel was resected and diverticulectomy was performed in the second case. Both patients are free of complaints now at 2 and 3 years of follow-up respectively. The genesis of diverticular bleeding, the difficulties of the preoperative diagnosis of the complicated diverticulum and the uncertain indication for operation in cases of uncomplicated diverticulum are discussed and the literature is reviewed.

MIPSY: real-time morphometry to quantify the time course of rapid epithelial restitution

The gastrointestinal mucosa has the ability to repair itself rapidly following superficial mucosal injury by rapid epithelial restitution. The mechanism consists of cell migration and does not involve mitosis. This study reports the mechanisms of rapid epithelial restitution in the rabbit colon in vivo and in the human colon in vitro, describes a new computerized real-time morphometry system to investigate the time course of restitution and presents a new method to calculate the migration speed of epithelia during the repair process. Superficial mucosal damage to the rabbit colon in vivo was produced by luminal exposure to 100 mM HCl for 5 min (80% of mucosal surface), a comparable injury in the human colon in vitro was obtained by luminal exposure to 10 mM HCl for 10 min (96% of mucosal surface). After detachment of the damaged tissue the intact epithelial cells in the vicinity of the necrosis extended pseudopodia and migrated over the denuded basal lamina. The morphological appearance of rapid epithelial restitution was the same in the rabbit and the human, only the time course was postponed in the human. The time course of rapid restitution was assessed by a newly developed computerized morphometry system (MIPSY). When tissues were examined after various time points following acid damage, 61% of the mucosa were damaged in the rabbit after 1 h, 10% after 2 hs and 20% after 5 hs. In the human colon 85% of the mucosal surface were damaged after 2 hs and 20% 5 hs after the end of acid exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

[The percutaneous catheter drainage of pancreatic pseudocysts]

The results of CT/US-guided percutaneous drainage in 35 patients with pancreatic pseudocysts are reported. 27 patients recovered without surgery and no further treatment was required. 8 patients required a subsequent surgery due to recurrence. The role of CT/US-guided percutaneous drainage in pancreatic pseudocysts as well as an analysis of the technical aspects associated with a successful procedure are discussed. Although US may be used, we believe CT is safer and allows more precise localisation and guidance in the treatment of pseudocysts.

Factors influencing the restitution of the duodenal and colonic mucosa after damage

Rapid epithelial restitution is an important protective mechanism which enables the gastrointestinal mucosa to reestablish epithelial integrity following superficial injury within hours. In this study we examined the influence of an acidic luminal pH, removal of the necrotic layer, nutrient bicarbonate, calcium and sodium desoxycholate (Na-DOC) on restitution in the rabbit duodenum in vitro and the role of Na-DOC and calcium for rapid restitution of the human colon in vitro. Transmucosal potential difference (PD), short-circuit current (lsc) were measured and resistance against passive ion flux (R) was calculated. Electrophysiological changes paralleled morphological injury but did not necessarily reflect restitution in all experiments. The extent of mucosal injury was assessed by computerized real-time morphometry. 5 hrs after luminal exposure to 10 mH HCl for 10 min residual damage (RD) was 14% in the duodenum. Luminal pH of 3.0 (RD of 30%), removal of necrotic layer at acidic luminal pH (RD of 66%), absence of bicarbonate from the serosal solution (RD of 35% at neutral luminal pH; RD of 96% at acidic luminal pH) and removal of calcium from the serosal solution (RD of 58%) impaired restitution in the duodenum. Continuous postinjury luminal Na-DOC exposure did not influence restitution in the duodenum (RD of 19%). 5 hrs after luminal exposure to 0.5 mM Na-DOC for 10 min RD was 26% in the human colon. Continuous postinjury luminal Na-DOC exposure (RD of 51%) and removal of calcium from the nutrient solution (RD of 65%) impaired restitution in the human colon. Thus we conclude that restitution of the rabbit duodenum in vitro requires a necrotic layer and bicarbonate flux to withstand acidic luminal pH, while restitution is not affected by Na-DOC. In the human colon Na-DOC inhibits restitution. Both the duodenum and colon require calcium for rapid restitution.

[Rectal cancer: prognostically relevant factors for the development of local recurrence following radical anterior resection]

The study was designed to detect criteria which influence the incidence of local recurrence after radical anterior resection for rectal cancer. Local recurrence developed in 18 patients (20%) out of 90. All patients entered a prospective clinical study for the detection of local recurrence (mean observation time: 50 months). The following criteria were evaluated retrospectively: age, sex, staging, grading, gross appearance of the tumour, lymphatic reaction, invasion of lymph and blood vessels, perineural invasion, mucus production of the tumour and width of the distal margin of clearance (measurement in cm in the specimen immediately after resection). Kaplan-Meier survival functions estimated the probability of staying free of local recurrence depending on the various criteria. Statistical significance was calculated using the tests of Breslow and Mantel. The incidence of local recurrence (%) depended on Dukes stage (A: 7%, B: 17%, C: 40%; p less than or equal to 0.03), grading (well differentiated: 5%, average: 20%, poorly differentiated: 55%; p less than or equal to 0.02), gross appearance (protuberant: 15%, infiltrating: 47%; p less than or equal to 0.006), lymphatic stroma reaction (yes: 10%, no: 45%; p less than or equal to 0.006), invasion of veins (yes: 75%, no: 20%; p less than or equal to 0.002), perineural invasion (yes: 52%, no: 17%; p less than or equal to 0.001) and the margin of clearance (less than 1 cm: 52%, 1-3 cm: 10%, greater than 3 cm: 15%; p less than or equal to 0.02 Mantel, p less than or equal to 0.05 Breslow between less than 1 cm vs. 1-3 cm and greater than 3 cm, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

[Intracellular pH regulation in human SW-620 colon cancer cells]

Intracellular pH (pHi) regulation is essential for basic functioning of the cell and activation of pHi regulatory mechanisms appears to be involved in the initial stage of cell division. Little is known about pHi regulation in human colonic carcinoma cells. We investigated SW-620 (CCL 227) cells, a cell-line derived from a human colonic adenocarcinoma. pHi changes were recorded by computer-assisted spectrofluorimetric monitoring of the pH-sensitive, fluorescent dye BCECF (2',7'-bis(carboxyethyl)- 5(6)carboxyfluorescein). Resting pHi in HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) buffered solution was 7.53 +/- 0.01. Intracellular acidification after an ammonium prepulse produced a pHi decline of 0.5 units and pHi returned to normal value in NaCl Ringer's. Both 1 mM amiloride and Na-free solution completely inhibited recovery for 8 minutes. This inhibition was reversible in NaCl Ringer's. Na-free solution led to a pHi decrease to 7.39 +/- 0.04 after 16 min, pHi was also lowered by 8 minute incubation of cells with 1 mM amiloride (7.40 +/- 0.02). In HCO3/CO2-buffered solution resting pHi was 7.42 +/- 0.01 (n = 35). Recovery from an acute acid load, induced by NH4 prepulse or switching from HEPES- to bicarbonate-buffered solution, was Na dependent, Cl independent, reversible and only partially blocked by 1 mM amiloride - pHi slowly recovered from 6.83 +/- 0.03 to 7.00 +/- 0.06 in 8 minutes. In the presence of amiloride and 200 microns H2DIDS (dihydro-4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid) pHi recovery was completely inhibited for 8 minutes. In Na-free solution pHi decreased from 7.44 +/- 0.04 to 7.29 +/- 0.03 within 8 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of stress ulceration and implications for treatment

The incidence of stress ulceration and its complications has decreased over the last decade significantly. The reason for this development is the better understanding of the protective mechanism of stomach and duodenum as well as the prophylactic treatment. This can be achieved by antacids, H2-blockers, and sucralfate, whereas prostaglandins are not effective.

Rapid epithelial restitution of human and rabbit colonic mucosa

Rapid epithelial restitution is now considered one of the primary defense mechanisms of the stomach and duodenum. Because there is currently no evidence as to whether restitution occurs in human tissue, this study examined human and rabbit colonic mucosa after superficial injury and monitored the potential difference, alkaline flux, and speed and mechanisms of mucosal restitution as observed with light and electron microscopy. Luminal exposure of the in vivo rabbit colon to 100 mM HCl for 5 min or the in vitro human colon to 10 mM HCl for 10 min caused superficial mucosal injury to 76% of the epithelial surface in the rabbit and 95% in the human. The necrotic epithelial cells detached in sheets from the intact basal lamina and formed a protective mucoid layer. Morphologic evidence of restitution occurred within 15 min after injury in the rabbit and 30 min in the human, as viable nongoblet cells projected lamellipodia and migrated over the denuded basal lamina at a speed of approximately 2 microns/min. One hour after damage 61% of the mucosal surface was still damaged in the rabbit, and 86% of the human mucosal surface was damaged after 2 h. In the following 60 min restitution progressed rapidly, so that only 10% of the surface remained unrepaired in the rabbit after 2 h and 19% in the human after 3 h. Small areas with deeper injury did not repair until 5 h after damage. The potential difference dropped after mucosal injury and did not recover despite morphologic repair. Rapid epithelial restitution is considered to be a basic defense mechanism of the gastrointestinal mucosa that is obviously not necessarily related to the presence of an acidic environment in the stomach or duodenum.

Importance of an alkaline microenvironment for rapid restitution of the rabbit duodenal mucosa in vitro

Rapid epithelial restitution after superficial damage of the gastroduodenal mucosa consists of the migration of remaining intact epithelial cells beneath a necrotic layer of mucus and shed cells. Complete reepithelialization occurs within 60 min (rat stomach) to 7 h (rabbit duodenum) and does not involve cell division. The present study investigated rapid restitution of the acid-damaged rabbit duodenal mucosa in vitro under various conditions. Alkaline flux and transmucosal potential difference were measured simultaneously, and computerized morphometry was performed. Rapid restitution was nearly completed 5 h after damage at neutral luminal pH, but it was retarded when the luminal pH (pHL) was kept at 3. Removal of the necrotic layer did not impair restitution at neutral luminal pH but caused delay at acidic pH (pHL = 3.0). Removal of nutrient bicarbonate slightly delayed restitution at pHL = 7.4 and caused complete inhibition at pHL = 3.0. Alkaline secretion was usually stable but was nearly totally abolished after removal of nutrient bicarbonate. The potential difference decreased after acid damage and showed a tendency to recover in parallel with mucosal restitution. This gradual recovery correlated directly with morphometry. The authors assume that rapid restitution of the duodenal mucosa at an acidic luminal pH depends on the presence of a protective necrotic layer and sufficient alkaline secretion to maintain an optimal environment adjacent to the mucosa. Disturbance of this alkaline microenvironment could be important for the development and healing of duodenal ulcer.

[Familial colon cancer]

5 families with autosomal dominant inherited colonic cancer were analyzed with reference to the characteristics of familial colonic cancer: 45% out of 54 family members had colorectal carcinomas, with a mean of 4.5 affected members per family. The mean age on diagnosis of colonic cancer was 43.9 years. 50% of the colorectal carcinomas were located in the right colon; 11 out of 14 carcinomas were Dukes C, with a predominance of poorly differentiated adenocarcinomas and mucin-producing cancers. 22% had synchronous cancers and 13% developed metachronous cancers. Cancer at another location was found in 8.7% of cases. Prospective screening of relatives (siblings, children) revealed a colonic neoplasm in 3 out of 6 asymptomatic subjects. The typical characteristics of familial colonic cancers were demonstrable in our patients. The elucidation of an exact family history in all patients with colorectal carcinoma and a strategy of meticulous surveillance are absolutely necessary for the diagnosis and management of this inherited trait.

[Minor surgery]

The main task of the general practitioner is not only the early diagnosis of oncologic diseases and the follow-up of these patients, but also the emergency treatment of acute disorders as well as outpatient surgery. This summary overlooks the surgical facilities of the general practitioner to perform urgent and elective outpatient surgery. In addition, the focus is on the management of acute disorders and complications.

Rectal cancer: factors influencing the development of local recurrence after radical anterior resection

The study was designed to select criteria which influence the incidence of local recurrence after radical anterior resection for rectal cancer. Local recurrence developed in 18 patients (20%) out of 90. All patients entered a prospective clinical study for the detection of local recurrence (mean observation time: 50 months). The following criteria were evaluated retrospectively: age, sex, staging, grading, gross appearance of the tumour, lymphatic reaction, invasion of lymph- and blood vessels, perineural invasion, mucus production of the tumour and width of the distal margin of clearance (measurement in cm in the specimen immediately after resection). The incidence of local recurrence (%) depended on Dukes stage (A: 7%, B: 17%, C: 40%; p less than or equal to 0.03), grading (well differentiated: 5%, average: 20%, poorly differentiated: 55%; p less than or equal to 0.02), gross appearance (protuberant: 15%, infiltrating: 47%; p less than or equal to 0.006), lymphatic stroma reaction (yes: 10%, no: 45%; p less than or equal to 0.006), invasion of veins (yes: 75%, no: 20%; p less than or equal to 0.0002), perineural invasion (yes: 52%, no: 17%; p less than or equal to 0.001) and the margin of clearance (less than 1 cm: 52%; 1-3 cm: 10%, greater than 3 cm: 15%; p less than or equal to 0.02 Mantel, p less than or equal to 0.05 Breslow between less than 1 cm vs 1-3 cm and greater than 3 cm, respectively). Local recurrence was not related to age, sex and mucus production of the tumour. Unfavourable morphological criteria may help to define groups with a higher risk of developing local recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamic and metabolic changes during orthotopic liver transplantation]

Hemodynamic and metabolic profiles were obtained on 48 adult patients (mean age 46 years) undergoing orthotopic liver transplantation without using a bypass technique during the anhepatic period. Baseline measurements after induction of anesthesia (A) revealed a high-output circulatory state. During hepatic dissection (B, preclamping control), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), and elevated cardiac index (CI) were well maintained. Preoperative plasma exchange with fresh frozen plasma in the presence of severe coagulation defects and liberal use of platelet concentrates limited the need for massive blood transfusion, and thus contributed to stable hemodynamics during this stage. Significant cardiovascular changes occurred immediately after clamping of the inferior vena cava and the portal vein (C): there was a marked fall in MAP (-30%), MPAP (-45%), PCWP (-48%), RAP (-40%), and CI (-60%) reflecting the hemodynamic adaptation to the impeded venous return. At the end of the anhepatic period (D), MAP (-21%), MPAP (-38%), PCWP (-39%), RAP (-24%), and CI (-56%) were persistently lowered because no attempts were made to attenuate the clamping response by vigorous volume expansion or infusion of inotropic drugs. The reduction in oxygen availability index (O2AVI) was compensated by enhanced oxygen extraction. Oxygen consumption index (VO2I) fell secondary to the removal of the liver and the decrease in body temperature (BT). Potassium levels and acid-base balance were well controlled; no hypoglycemic episode was observed during the anhepatic period.(ABSTRACT TRUNCATED AT 250 WORDS)

[Secondary achalasia caused by diffuse infiltrating cardial cancer]

Malignant tumors, especially gastric adenocarcinomas infiltrating into the submucosa of the esophagus, can result in a clinical syndrome termed secondary or pseudo-achalasia that mimicks idiopathic primary achalasia. History, symptoms, radiology, esophago-gastroscopy with biopsy, and esophageal manometry do not discriminate secondary from primary achalasia at initial evaluation. The difficulty in establishing the diagnosis is demonstrated on the case of a 57-year old man presenting with dysphagia, vomiting, and weight loss. Fluoroscopically, the esophagus was moderately dilated and bird-beaked. The patient underwent two gastroesophagoscopies, in the second of which the endoscope could not be passed through the esophagogastric junction. Esophageal manometry revealed an only partial relaxation of the lower esophageal sphincter upon swallowing and nonpropulsive, repetitive contractions in the esophageal body, compatible with the diagnosis "vigorous achalasia". After two mechanic dilatations, a myotomy of the sphincter seemed indicated. At operation, a cardiac carcinoma infiltrating submucosally into the esophagus was found. The recognition of secondary achalasia is difficult, and signs such as older age, brief duration of symptoms, marked weight loss and the presence of vigorous achalasia, relatively rare in primary achalasia, are unspecific. Hence, in all instances in which secondary achalasia cannot be ruled out, it seems advisable to perform an explorative laparotomy with eventual sphinctermyotomy as primary therapeutic intervention instead of a mechanic dilatation, which potentially further obscures the underlying disease. To enable the recognition of undetected secondary achalasia, all patients with achalasia should be followed up thoroughly.

Results of a rigorous follow-up system in colorectal cancer

Results of a computer-aided follow-up programme for patients with colorectal cancer are analyzed. Between 1978 and 1987 1293 patients underwent this programme, the drop-out rate was 17%. 299 recurrences in 168 patients were discovered (40% local recurrence, 29% liver metastases and 31% others). Fifty-one per cent of patients with local recurrence and 47% with liver metastases were symptom free. Radical surgery could be performed in 50% of local recurrences and in 26% of liver metastases. The three year survival rate after radical surgery for recurrence was 35% for local recurrences and 33% for liver metastases, the five-year-survival rate 23% and 15%, respectively.

[Repair of the duodenal mucosa following acid damage. A protective mechanism as an approach to new therapeutic principles?]

Epithelial repair after luminal acid exposure was studied in the rabbit duodenum in vivo, HCl (200 mM for 30 min) caused uniform damage of the mucosa confined to the villi, 50% of the total villus height was affected by the acid-induced lesion in the proximal, and 70% in the distal duodenum. After demarcation and detachment of the necrotic tissue the defect was bridged by the remaining viable epithelial cells underneath a layer of mucus and necrotic debris (= necrotic layer). Mucosal repair resulted in a reduction of villus height by 62% in the proximal, and 77% in the distal duodenum. This process of mucosal repair progressed continuously, so that 9 hours after acid damage only 33% of villi in the proximal, and 41% in the distal duodenum were not yet fully restored, irrespective of luminal pH(pHL = 7 or pHL = 3). The difference between proximal and distal duodenum is due to the higher acid susceptibility of the distal duodenum. Rapid epithelial repair of the duodenal mucosa in vivo provides an important protective mechanism against the aggression from luminal acid.

Acid stimulated alkaline secretion in the rabbit duodenum is passive and correlates with mucosal damage

Low luminal acid concentrations stimulate alkaline secretion (AS) by the duodenal mucosa. We investigated acid stimulated alkaline secretion by proximal rabbit duodenal mucosa in an Ussing-chamber under different luminal acid concentrations and its relation to mucosal damage. Luminal alkalinisation and potential difference (PD) were measured and mucosal damage was investigated histologically. Luminal acid caused an increase of alkaline secretion over baseline (0.95 +/- 0.19 mu Eq/cm2/10 min; n = 55): 0.1 mmol: 7%, 1 mmol/l: 17%, 5 mmol/l: 22%, 10 mmol/l: 33%, 20 mmol/l: 34%, 50 mmol: 39%, 100 mmol/l: 27%. At acid concentrations of 10 mmol/l and above the PD fell from 2.0 +/- 1.0 mV to zero. Histology showed [H+]-dependent mucosal damage ranging from villus tip lesions to deep mucosal injury. Stimulation of alkaline secretion was not specific for acid. Ethanol (14%) stimulated alkaline secretion by 26%, and 28% ethanol by 40% over baseline. Ouabain and/or anoxia sensitive (active) alkaline secretion constituted 80% and 100% respectively of basal alkaline secretion. After exposure to various luminal acid concentrations passive diffusion (sensitive only to removal of nutrient HCO3-) was solely responsible for the rise in alkaline secretion. Only after 14% ethanol a small rise in ouabain and/or anoxia sensitive HCO3- transport was observed. Under the conditions of this study stimulation of duodenal alkaline secretion is not specific for luminal acid, but occurs also with luminal ethanol; both agents stimulate alkaline secretion depending on their concentration. In this model passive diffusion of HCO3- associated with increasing mucosal damage is the major component of the rise in alkaline secretion.

[Significance of alkali secretion in acid tolerance of the rabbit duodenum]

Different rates of alkaline secretion and their effect on acid tolerance were investigated in segments of proximal duodenum of anaesthetized New Zealand white rabbits in situ. Metabolic alkalosis and glucagon led to a significant increase in alkaline secretion, while metabolic acidosis, vasopressin and furosemide significantly reduced alkaline secretion. Mucosal blood flow was significantly increased by glucagon and decreased by vasopressin. Alkaline secretion after an acid challenge was significantly higher than preacid secretion in animals with metabolic alkalosis, glucagon and NaCl, whereas vasopressin reduced alkaline secretion significantly. No significant change was observed during treatment with furosemide or metabolic acidosis. After perfusion with acid, 51.8% of the villi showed superficial damage (stage 1) under control conditions. Damage was significantly reduced after administration of bicarbonate or glucagon, while NH4Cl, vasopressin or furosemide increased damage both quantitatively and qualitatively. There was a direct linear correlation between the degree of damage and alkaline secretion. The proximal duodenum showed considerably less damage than the distal segment. We conclude that a decrease in alkaline secretion is associated with a reduced tolerance of duodenal mucosa to luminal acid, whereas stimulation of alkaline secretion improves mucosal protection. These results support the hypothesis that alkaline secretion is an important factor in the protection of the duodenum against luminal acid.

[Value of consistent after care in stomach cancer]

This study analyses the efficacy of a consistent, strict follow-up programme in the management of patients with gastric cancer. Between 1978 and 1986 671 patients were treated, of whom 361 (54%) had a radical operation. The data were fed into an electronic data base and patients were invited to attend the follow-up investigations. The drop-out rate was 21%. Recurrence was detected in 177 cases, 25% in the liver, 25% as carcinosis, 21% in lymph nodes, 15% locally and 14% in other localizations. 78% of the recurrences were seen two years postoperatively and 27% were asymptomatic; 10% underwent radical operation, 27% palliative operation and 63% conservative treatment. Survival rates after 3 and 5 years were 73% and 62% in patients without recurrence and 21% and 8% with recurrence, respectively (p = 0.0 Breslow and Mantel test). The survival rate 2 years after treatment of recurrence was 37% after radical surgery and 0% after palliative operations or conservative treatment (p less than 0.06 Breslow and p less than 0.002 Mantel test). Furthermore, a tight follow-up programme enables control of surgical quality and accurate follow-up during clinical trials, whilst the opportunity to advise patients after operation is an important aspect.

[Non-Hodgkin's lymphoma of the stomach: surgical therapy and prognosis]

This study reports 43 patients (male: n = 17, female: n = 26) with non-Hodgkin's lymphoma of the stomach, who underwent surgery between 1. January 1977 and 31. December 1986. The main clinical symptoms were abdominal pain, weight loss and vomiting. Symptoms preceded diagnosis by 13 weeks. Barium meal and endoscopy were useful diagnostic procedures. The biopsy specimens indicated malignancy in 80% of cases. Operations performed were: total gastrectomy (n = 18), distal resection (B I: n = 4, B II: n = 14), partial duodenopancreatectomy (n = 3), proximal gastric resection (n = 1), local excision (n = 1) and explorative laparotomy (n = 2). Perioperative mortality was 0%. Peritonitis occurred in 1 patient due to leakage of the duodenal stump. According to the Ann-Arbor system we found stage I in 19, stage II in 10 and stage III in 14 cases. The histological type according to the Working Formulation showed low grade of malignancy in 15 and high grade of malignancy in 28 patients. All patients underwent postoperative chemotherapy and/or radiotherapy with respect to tumour staging and morphology. 24 patients are alive without relapse, 16 patients died intercurrently. The data were collected retrospectively and analysed by means of Kaplan-Meier survival functions. For comparisons we used the Breslow and the Mantel test. We investigated the prognostic significance of: sex, clinical symptoms, localisation of the tumour, type and radicality of operation, lymphadenectomy, splenectomy, splenic infiltration, tumour size and depth of infiltration, staging and grading. The 2-year survival rate was 82%, the 5-year rate was 55%.(ABSTRACT TRUNCATED AT 250 WORDS)

Repair of rabbit duodenal mucosa after acid injury in vivo and in vitro

Epithelial repair after luminal acid exposure was studied in the rabbit duodenum in vivo and in vitro. Hydrochloric acid (200 mM, 30 min in vivo; 10 mM, 10 min in vitro) caused a uniform damage of the mucosa confined to the villi. After demarcation and detachment of the necrotic tissue the defect was bridged by the remaining viable epithelial cells, resulting in a reduction of villus height. This process of mucosal repair proceeded continuously, so that 9 h after acid damage only 33% of villi in the proximal duodenum and 41% in the distal duodenum remained not fully restored, at both luminal pH 7 and luminal pH 3. The difference is due to the higher acid susceptibility of the distal duodenum. In vitro, most of the mucosal surface was reconstituted 5 h after acid injury, at both luminal pH 7.4 and luminal pH 3. The potential difference declined and reversed after mucosal damage; restitution to original values was only observed at luminal pH 7 in vivo and luminal pH 7.4 in vitro.

The effect of acid perfusion on mucosal blood flow and intramural pH of rabbit duodenum

To evaluate the role of blood flow for acid tolerance of the duodenal mucosa, we perfused the duodenums of anesthetized rabbits with different concentrations of hydrochloric acid (HCl). Acid perfusion stimulated blood flow to the duodenal wall in a concentration-dependent fashion up to 80 mmol/L HCl (0 mmol/L; 0.44 +/- 0.05, 10 mmol/L; 0.84 +/- 0.14, 50 mmol/L; 1.44 +/- 0.11, 80 mmol/L; 2.03 +/- 0.12, 100 mmol/L; 1.82 +/- 0.07 ml/gm/min X +/- SEM). The pH in the lamina propria of the mucosa, which was measured with antimony microelectrodes was not changed in experiments during perfusion with 50 and with 80 mmol/L HCl in normotension. Acidosis in the lamina propria could be demonstrated only when the duodenum was perfused with 100 and with 80 mmol/L HCl combined with hemorrhagic hypotension. Damage to the mucosa, which developed after 30 and 60 minutes of acid perfusion, also showed a H+-dependent pattern. Reduction of blood flow by hemorrhagic hypotension aggravated the morphologic damage. We conclude that luminal acid stimulates blood flow in the duodenum. The decrease in blood flow induced by hypotension results in a greater susceptibility to mucosal damage.

Alkaline secretion. A protective mechanism against acid injury in rabbit duodenum

The role of alkaline secretion in the protection against acid-induced (50 mM HCl) damage was investigated in the perfused rabbit duodenum. Basal alkaline secretion was 3.86 +/- 0.23 mu Eq/cm2 . 10 min (pH-stat method). Perfusion with HCl increased alkaline secretion to 4.39 +/- 0.17 mu Eq/cm2 . 10 min and led to superficial damage of 51.8% of the villi. Intravenous treatment with NaHCO3 and glucagon increased alkaline secretion (+25% and +37%, respectively) and decreased damage (-27.7% and -25.3%, respectively), whereas mucosal blood flow as assessed by radioactive microspheres was stimulated only by glucagon. Intravenous treatment with NH4Cl, vasopressin, and furosemide decreased alkaline secretion (-31%, -52%, and -50%, respectively) and led to increased damage (+18.5%, +19.3%, and +19.6% superficial and 30%-50% deep lesions), and mucosal blood flow was decreased (vasopressin) or unchanged. There was a direct linear relationship (r = 0.88, y = 103-15.8x) between the degree of damage and alkaline secretion. These results support the hypothesis that duodenal alkaline secretion is indeed a protective factor against acid damage.

[Consequences of after-care in colorectal cancer]

Results of a computer supported follow-up-program on patients with colorectal cancer are presented. Between 1978 and 1985 1024 patients underwent these program, the drop-out-rate was 18%. 231 recurrences in 137 patients were discovered (40% local recurrence, 30% liver metastases and 30% others). 54% of patients with local recurrence and 43% with liver metastases were free of symptoms. Radical surgery was performed in 47% of local recurrences and in 24% of liver metastases. The three year survival rate after radical surgery for recurrence amounted to 28% for local recurrences and to 31% for liver metastases.