Microflora and deconjugation of bile acids in alkaline reflux after partial gastrectomy

Serum Total Bile Acids in Relation to Gastrointestinal Cancer Risk: A Retrospective Study

Background

Bile acids (BAs) have been proposed to promote gastrointestinal cells carcinogenesis. However, studies on serum total bile acid (TBA) levels and gastrointestinal cancers (GICs) risk are rare.

Methods

We conducted a retrospective case-control study from 2015 to 2019 at the First Affiliated Hospital of Air Force Military Medical University, in which 4,256 GICs cases and 1,333 controls were recruited. Patients' demographic, clinical and laboratory data were collected. The odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using binary logistic regression models.

Results

Positive associations were observed between serum TBA levels and risks of esophageal cancer (EC), gastric cancer (GC) and colorectal cancer (CRC). Overall, ORs of EC, GC and CRC risk rose with the TBA levels increasing. After adjustment for potential confounders, the OR of TBA-positive for EC risk was 4.89 (95% CI: 3.20-7.49), followed by GC (OR: 3.92, 95% CI: 2.53-6.08), and CRC (OR: 3.32, 95% CI: 2.04-5.11). Patients aged 60 years or older have a higher risk of GICs, especially for EC patients. Males are associated with a higher risk of GC, while females are associated with a higher risk of CRC. Preoperative serum TBA positive and negative was significantly different in the presence or absence of hematogenous metastasis among EC patients (P=0.014), and lymph node metastasis among GC patients (P=0.018).

Conclusions

This retrospective study showed positive associations between serum TBA level and GICs risk, and a higher serum TBA level constitutes a risk factor for GICs.

Noxious Combination of Tobacco Smoke Nitrosamines with Bile, Deoxycholic Acid, Promotes Hypopharyngeal Squamous Cell Carcinoma, via NFκB, In Vivo

Tobacco smoking is the most known risk factor for hypopharyngeal cancer. Bile reflux has recently been documented as an independent risk factor for NFκB-mediated hypopharyngeal squamous cell carcinoma. However, the carcinogenic effect of tobacco smoke on the hypopharynx and its combination with bile has not yet been proven by direct evidence. We investigated whether in vivo chronic exposure (12-14 weeks) of murine (C57Bl/6J) hypopharyngeal epithelium to tobacco smoke components (TSC) [N-nitrosamines; 4-(N-Methyl-N-Nitrosamino)-1-(3-pyridyl)-1-butanone (0.2 mmol/L), N-nitrosodiethylamine (0.004 mmol/L)], as the sole drinking fluid 5 days per week, along with topically applied (two times/day) bile [deoxycholic acid (0.28 mmol/L)], can accelerate a possible TSC-induced neoplastic process, by enhancing NFκB activation and the associated oncogenic profile, using histologic, IHC, and qPCR analyses. We provide direct evidence of TSC-induced premalignant lesions, which can be exacerbated by the presence of bile, causing invasive carcinoma. The combined chronic exposure of the hypopharynx to TSC with bile causes advanced NFκB activation and profound overexpression of Il6, Tnf, Stat3, Egfr, Wnt5a, composing an aggressive phenotype. We document for the first time the noxious combination of bile with a known risk factor, such as tobacco smoke nitrosamines, in the development and progression of hypopharyngeal cancer, via NFκB, in vivo. The data presented here encourage further investigation into the incidence of upper aerodigestive tract cancers in smokers with bile reflux and the early identification of high-risk individuals in clinical practice. This in vivo model is also suitable for large-scale studies to reveal the nature of inflammatory-associated aerodigestive tract carcinogenesis and its targeted therapy.

PREVENTION RELEVANCE

Early assessment of bile components in refluxate of tobacco users can prevent the chronic silent progression of upper aerodigestive tract carcinogenesis. This in vivo model indicates that bile reflux might have an additive effect on the tobacco-smoke N-nitrosamines effect and could be suitable for large-scale studies of diagnostic and therapeutic interventions.

Bile reflux and hypopharyngeal cancer (Review)

Laryngopharyngeal reflux, a variant of gastroesophageal reflux disease, has been considered a risk factor in the development of hypopharyngeal cancer. Bile acids are frequently present in the gastroesophageal refluxate and their effect has been associated with inflammatory and neoplastic changes in the upper aerodigestive tract. Recent in vitro and in vivo studies have provided direct evidence of the role of acidic bile refluxate in hypopharyngeal carcinogenesis and documented the crucial role of NF-κB as a key mediator of early oncogenic molecular events in this process and also suggested a contribution of STAT3. Acidic bile can cause premalignant changes and invasive squamous cell cancer in the affected hypopharynx accompanied by DNA damage, elevated p53 expression and oncogenic mRNA and microRNA alterations, previously linked to head and neck cancer. Weakly acidic bile can also increase the risk for hypopharyngeal carcinogenesis by inducing DNA damage, exerting anti-apoptotic effects and causing precancerous lesions. The most important findings that strongly support bile reflux as an independent risk factor for hypopharyngeal cancer are presented in the current review and the underlying mechanisms are provided.

Roles of the hexosamine biosynthetic pathway and pentose phosphate pathway in bile acid-induced cancer development

Esophageal squamous cell carcinomas (ESCCs) as well as adenocarcinomas (EACs) were developed in rat duodenal contents reflux models (reflux model). The present study aimed to shed light on the mechanism by which bile acid stimulation causes cancer onset and progression. Metabolomics analyses were performed on samples of neoplastic and nonneoplastic tissues from reflux models, and K14D, cultivated from a nonmetastatic, primary ESCC, and ESCC‐DR, established from a metastatic thoracic lesion. ESCC‐DRtca2M was prepared by treating ESCC‐DR cells with taurocholic acid (TCA) to accelerate cancer progression. The lines were subjected to comprehensive genomic analyses. In addition, protein expression levels of glucose‐6‐phosphate dehydrogenase (G6PD), nuclear factor kappa B (NF‐κB) (p65) and O‐linked N‐Acetylglucosamine (O‐GlcNAc) were compared among lines. Cancers developed in the reflux models exhibited greater hexosamine biosynthesis pathway (HBP) activation compared with the nonneoplastic tissues. Expression of O‐GlcNAc transferase (OGT) increased considerably in both ESCC and EAC compared with nonneoplastic squamous epithelium. Conversely, cell line‐based experiments revealed the greater activation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. G6PD overexpression in response to TCA exposure was observed. Both NF‐κB (p65) and O‐GlcNAc were expressed more highly in ESCC‐DRtca2M than in the other cell lines. Moreover, ESCC‐DRtca2M cells had additional chromosomal abnormalities in excess of ESCC‐DR cells. Overall, glucose metabolism was upregulated in both esophageal cancer tissue and cell lines. While bile acids are not mutagenic, chronic exposure seems to trigger NF‐κB(p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression. Glucose metabolism was upregulated in both esophageal cancer tissue and cell lines, and the HBP was activated in the former. The cell line‐based experiments demonstrated upregulation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. While bile acids are not mutagenic, chronic exposure seems to trigger G6PD overexpression and NF‐κB (p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression.

Safety Evaluation of Oral Care Probiotics Weissella cibaria CMU and CMS1 by Phenotypic |and Genotypic Analysis

Weissella cibaria CMU and CMS1 are known to exert beneficial effects on the oral cavity but have not yet been determined to be generally recognized as safe (GRAS), although they are used as commercial strains in Korea. We aimed to verify the safety of W. cibaria CMU and CMS1 strains through phenotypic and genotypic analyses. Their safety was evaluated by a minimum inhibitory concentration assay for 14 antibiotics, DNA analysis for 28 antibiotic resistance genes (ARGs) and one conjugative element, antibiotic resistance gene transferability, virulence gene analysis, hemolysis, mucin degradation, toxic metabolite production, and platelet aggregation reaction. W. cibaria CMU showed higher kanamycin resistance than the European Food Safety Authority (EFSA) cut-off, but this resistance was not transferred to the recipient strain. W. cibaria CMU and CMS1 lacked ARGs in chromosomes and plasmids, and genetic analysis confirmed that antibiotic resistance of kanamycin was an intrinsic characteristic of W. cibaria. Additionally, these strains did not harbor virulence genes associated with pathogenic bacteria and lacked toxic metabolite production, β-hemolysis, mucin degradation, bile salt deconjugation, β-glucuronidase, nitroreductase activity, gelatin liquefaction, phenylalanine degradation, and platelet aggregation. Our findings demonstrate that W. cibaria CMU and CMS1 can achieve the GRAS status in future.

Curcumin prevents the bile reflux-induced NF-κB-related mRNA oncogenic phenotype, in human hypopharyngeal cells

The presence of bile is not an uncommon finding in acidic oesophageal and extra‐oesophageal refluxate, possibly affecting the hypopharyngeal mucosa and leading to neoplastic events. We recently demonstrated that acidic bile (pH ≤ 4.0) can induce NF‐κB activation and oncogenic mRNA phenotype in normal hypopharyngeal cells and generate premalignant changes in treated hypopharyngeal mucosa. We hypothesize that curcumin, a dietary inhibitor of NF‐κB, may effectively inhibit the acidic bile‐induced cancer‐related mRNA phenotype, in treated human hypopharyngeal primary cells (HHPC), supporting its potential preventive use in vivo. Luciferase assay, immunofluorescence, Western blot, qPCR and PCR microarray analysis were used to explore the effect of curcumin in HHPC exposed to bile (400 μmol/L) at acidic and neutral pH. Curcumin successfully inhibited the acidic bile‐induced NF‐κB signalling pathway (25% of analysed genes), and overexpression of NF‐κB transcriptional factors, c‐REL, RELA(p65), anti‐apoptotic bcl‐2, oncogenic TNF‐α, EGFR, STAT3, WNT5A, ΔNp63 and cancer‐related IL‐6. Curcumin effectively reduced bile‐induced bcl‐2 overexpression at both acidic and neutral pH. Our novel findings suggest that, similar to pharmacologic NF‐κB inhibitor, BAY 11‐7082, curcumin can suppress acidic bile‐induced oncogenic mRNA phenotype in hypopharyngeal cells, encouraging its future in vivo pre‐clinical and clinical explorations in prevention of bile reflux‐related pre‐neoplastic events mediated by NF‐κB.

SINGLE ANASTOMOSIS GASTRIC BYPASS (ONE ANASTOMOSIS GASTRIC BYPASS OR MINI GASTRIC BYPASS): THE EXPERIENCE WITH BILLROTH II MUST BE CONSIDERED AND IS A CHALLENGE FOR THE NEXT YEARS

INTRODUCTION

Single anastomosis gastric bypass (one anastomosis gastric bypass or mini-gastric bypass) has been presented as an option of surgical treatment for obese patients in order to reduce operation time and avoiding eventual postoperative complications after Roux-en-Y gastric bypass.The main late complication could be related to bile reflux.

AIM

To report the experiences published after Billroth II anastomosis and its adverse effects regarding symptoms and damage on the gastric and esophageal mucosa .

METHOD

For data recollection Medline, Pubmed, Scielo and Cochrane database were accessed, giving a total of 168 papers being chosen 57 of them.

RESULTS

According the reported results during open era surgery for peptic disease and more recent results for gastric cancer surgery, bile reflux and its consequences are more frequent after Billroth II operation compared to Roux-en-Y gastrojejunal anastomosis.

CONCLUSION

These findings must be considered for the indication of bariatric surgery.

Deoxycholic Acid Could Induce Apoptosis and Trigger Gastric Carcinogenesis on Gastric Epithelial Cells by Quantitative Proteomic Analysis

Background. Pathologic duodenogastric reflux can induce or aggravate gastritis because of the presence of bile acids. Bile reflux has been generally considered to be associated with intestinal metaplasia and gastric cancer. However, the pathogenic mechanisms of the effects of bile acids on gastric mucosa are still unknown. Methods. To explore the mechanisms by which bile acids induce gastric mucosal lesions, we examined cell apoptosis in the gastric epithelial cell line GES-1 and investigated the changes in protein profiles of GES-1 cells in response to a bile acid deoxycholic acid using a proteomics approach. Changes in the profiles of the differently expressed proteins were analyzed using the DAVID and STRING programs. Results. We found apoptosis was significantly induced in GES-1 cells by deoxycholic acid. Using liquid chromatographic/tandem mass spectrometric (LC-MS/MS) methods, 134 upregulated proteins and 214 downregulated proteins were identified in the bile acid treated GES-1 cells. Bioinformatics analysis revealed the interactions and signaling networks of these differentially expressed proteins. Conclusion. These findings may improve the understanding of the molecular mechanisms underlying the pathogenicity of bile acids on gastric mucosa.

Gastric microbiota and predicted gene functions are altered after subtotal gastrectomy in patients with gastric cancer

Subtotal gastrectomy (i.e., partial removal of the stomach), a surgical treatment for early-stage distal gastric cancer, is usually accompanied by highly selective vagotomy and Billroth II reconstruction, leading to dramatic changes in the gastric environment. Based on accumulating evidence of a strong link between human gut microbiota and host health, a 2-year follow-up study was conducted to characterize the effects of subtotal gastrectomy. Gastric microbiota and predicted gene functions inferred from 16S rRNA gene sequencing were analyzed before and after surgery. The results demonstrated that gastric microbiota is significantly more diverse after surgery. Ralstonia and Helicobacter were the top two genera of discriminant abundance in the cancerous stomach before surgery, while Streptococcus and Prevotella were the two most abundant genera after tumor excision. Furthermore, N-nitrosation genes were prevalent before surgery, whereas bile salt hydrolase, NO and N2O reductase were prevalent afterward. To our knowledge, this is the first report to document changes in gastric microbiota before and after surgical treatment of stomach cancer.

Bile in the esophagus-model for a bile acid biosensor

Acid and bile acids form important constituents of the refluxed substances in patients who suffer from gastroesophageal reflux disease. Whilst 24h ambulatory pH monitoring using antimony or glass pH electrodes measures acid levels 5 cm above the gastroesophageal junction, there are no reliable methods of measuring other constituents of duodenal juices such as bile acids. Past studies in detection of bile acids have included esophageal aspiration studies with detection of bile acids with HPLC or indirect methods using fiber-optic bile sensor "Bilitec" to detect bilirubin in the bile. These methods have either been impracticable or unreliable for routine and accurate measurement of bile acid. More recently, impedance technology has been used to define "weakly" acid or alkaline reflux. There are many potential applications of biosensors of various types, and it is envisaged that a biosensor specific for bile acid would be a more practical tool for routine measurement. This paper looks at a model for development of a biosensor for bile acid based on molecular imprinted polymers.

Prevention of deoxycholate-induced gastric apoptosis by aspirin: roles of NF-kappaB and PKC signaling

BACKGROUND

Apoptosis is a major mechanism of gastric cell death induced by deoxycholate (DC) and aspirin (ASA), and the caspase cascade and protein kinase C (PKC) signaling play key roles in this process. The transcription factor kappa B (NF-kappaB) has been shown to modulate apoptosis by regulating the transcription of numerous pro- and anti-apoptotic genes. The aim of this study was to investigate the effect of DC and ASA on NF-kappaB signaling, and determine its role in programmed cell death in a human gastric carcinoma cell line.

METHODS

Cells were incubated with DC in the presence or absence of ASA or proteasome inhibitors (PI- I, lactacystin, and MG-132). Cell lysates were evaluated by Western blotting. NF-kappaB (p65) was measured in the cytosol and nuclear fractions.

RESULTS

DC induced a translocation of NF-kappaB into the nuclear compartment that was completely blocked by proteasome inhibitors. Although, ASA itself had no effect on the NF-kappaB pathway, nor did it reduce DC-induced NF-kappaB translocation, it did prevent DC-induced caspase-3, -6 and -9 activation, poly (ADP-ribose) polymerase and lamin A processing, DNA degradation, and PKC signaling, all indices of apoptosis. In contrast, proteasome inhibitors had no effect on DC-induced apoptosis.

CONCLUSIONS

Deoxycholate activates NF-kappaB at the same time that it induces apoptosis in gastric epithelial cells. Prevention of NF-kappaB activation does not alter DC-induced apoptosis, indicating that in our experimental conditions, NF-kappaB is not essential for apoptosis to proceed. In contrast, the ability of aspirin to restore the alterations in PKC isoforms induced by DC and at the same time prevent caspase cascade activation suggests the importance of the PKC signaling system in this process.

Mucin expression in reactive gastropathy: an immunohistochemical analysis

CONTEXT

Reactive gastropathy is the second most common diagnosis made on gastric biopsies. Increased epithelial proliferation and modifications of epithelial cytokeratin profile, distinct from those of Helicobacter pylori gastritis, have been previously reported. However, the evaluation of mucins, important components of the protective mucosal mucous layer, has not been reported.

OBJECTIVE

To investigate alterations of membrane and secreted mucins in reactive gastropathy of various etiologies using antibodies against mucin glycoproteins.

DESIGN

Thirty-eight gastric biopsies diagnosed as reactive gastropathy, related to nonsteroidal anti-inflammatory drugs (n = 18) or bile reflux (n = 6) or of indeterminate etiology (n = 14), were evaluated using antibodies to MUC1, MUC5AC, MUC6, and MUC2. All cases were confirmed to be negative for H. pylori. The biopsies were classified in 3 groups based on the severity of cytoarchitectural changes (mild, moderate, and severe). Mucin expression and its distribution were recorded and the results correlated with the cytoarchitectural alterations and etiologies.

RESULTS

Loss of MUC1, either patchy or complete, was noted in 67% of the cases. Aberrant expression of MUC5AC in pyloric glands was observed in 81% of the cases, and aberrant expression of MUC6 in the upper foveolar epithelium was diffusely seen in 14% of the cases. Aberrant expression of MUC2 in non-goblet cells was observed in a single case. Aberrant expression of MUC6 was less extensive in the nonsteroidal anti-inflammatory drugs group than in other 2 groups (P = .03). Concurrently, the diffuse distribution of aberrant MUC6 expression was seen only in the cases of severe gastropathy (P = .09). There was no correlation between modifications in expression of other mucins and either the etiologies or the severity of cytoarchitectural changes.

CONCLUSIONS

Expressions of membrane (MUC1) and secreted (MUC5AC, MUC6) mucins are frequently modified in reactive gastropathy. The alteration of MUC1, which is involved in cell adhesion and polarity, may play a role in the development of the serrated profile of reactive gastropathy. Milder modifications of the secreted mucins may be explained by the reactive/regenerative nature of the process. Importantly, theses changes are different from the increase in MUC6 and reduction of MUC5AC expression reported in H. pylori gastritis, underlying their mechanistic differences. It is worth noting that similar alterations of mucin expression are shared by various etiologies, that is, nonsteroidal anti-inflammatory drugs and bile reflux, consistent with the nonspecific nature of reactive gastropathy.

Protein kinase C involvement in deoxycholate-induced apoptosis in human gastric cells

Bile acids, such as deoxycholic acid (DC), are known to mediate some of their actions by differentially activating various protein kinase C (PKC) isoforms. This study confirms that DC induces apoptosis in gastric epithelial cells through PARP and caspase cascade activation, and examined the role of PKC in DC-induced apoptosis. We found increased activation of PKC in membrane fractions in response to DC that was concentration and time related. The PKC (beta(I)) isoform expression increased with translocation into the cell membrane fraction after DC (300 microM) stimulation. In contrast, PKCepsilon expression markedly decreased in response to DC treatment in a time- and concentration-dependent manner. In addition, this process was regulated by caspases, since the pan-caspase inhibitor z-VAD-fmk and caspase-3-, -6-, and -9-specific inhibitors prevented PKC (beta(I)) and (epsilon epsilon processing induced by DC. Treatment with the caspase-8-specific inhibitor, however, did not affect expression of either PKC isoform. No significant differences in the apoptotic response were observed when PKC (epsilon) overexpressed cells were exposed to DC in the presence of calcium-dependent conventional PKC inhibitors (Gö 6850 or Gö 6976). Our findings demonstrate that PKC is activated in gastric epithelial cells treated with DC with the PKC (beta(I)) and PKC (epsilon) isoforms being particularly involved in this process. The processing of PKC (beta(I) and epsilon) was shown to be closely regulated by caspases; however, modulations in PKC isoform concentrations by themselves have no effect on the apoptotic death of gastric mucosal cells induced by DC.

Thioproline prevents carcinogenesis in the remnant stomach induced by duodenal reflux

An excessive duodenal reflux induced by surgery has been widely accepted to cause gastric carcinogenesis in the remnant stomach. As one of causative factors for malignancy, N-nitroso compounds produced by enteric bacteria have been postulated. However, there is no concrete information to prove this hypothesis. This study was undertaken to elucidate the factors underlying the remnant stomach carcinogenesis, by giving thiazolidine-4-carboxylic acid (thioproline; TPRO) to the rats with duodenal reflux as a nitrite scavenger. Operated 39 animals were used, divided into 2 groups; one with a diet containing 0.5% TPRO (n=18), and the other with a diet without TPRO (n=21). Adenocarcinoma developed in 16 rats out of 21 (76.2%) of untreated rats, whereas adenocarcinoma was detected in 1 rat of the TPRO-treated rats (5.6%). TPRO thus prevented the development of gastric cancer in the remnant stomach, thereby suggesting a concern of nitroso compounds to the carcinogenesis.

Apoptosis is a major mechanism of deoxycholate-induced gastric mucosal cell death

This study was undertaken to determine whether necrosis or apoptosis was the predominant mechanism responsible for gastric mucosal cellular death using the cell line known as AGS cells. Cells were exposed to various concentrations of deoxycholate (DC; 50-500 muM) for periods ranging from 30 min to 24 h. Lactic dehydrogenase (LDH) activity was used as a marker for necrotic cell death, whereas apoptosis was characterized by 4',6-diamidino-2 phenylindole staining, DNA gel electrophoresis, terminal deoxynucleotidyl transferase dUTP nick-end labeling assay and DNA-histone-associated complex formation. When cells were bathed in Hank's balanced salt solution, DC-induced necrosis was the predominant mechanism of cell death. In contrast, when cells were bathed in Ham's F-12 solution (a more physiologically relevant medium), no evidence of cytotoxicity (by LDH assay) was discernible when cells were exposed to DC (50-300 muM) for periods as long as 8 h; instead, clear evidence of apoptosis was noted that was time and dose dependent. When cells were exposed for 24 h to these DC concentrations, cytotoxicity was also present, indicating necrosis as well. Furthermore, acidification of the ambient environment also evoked a necrotic response when exposed to DC. We demonstrated that apoptosis induced by DC shows early activation of caspase-3 that is dependent on both receptor and mitochondrial pathways. Our results indicate that physiological concentrations of DC (50-300 muM) primarily induce cellular death through an apoptotic process. Only after prolonged exposure to DC or acidification of the bathing solution does necrosis also occur.

Gastric carcinogenesis by duodenal reflux through gut regenerative cell lineage

To elucidate the histogenesis of gastric stump cancer, we performed an operation in rats to make all duodenal contents flow back into the glandular stomach. The subjects were 41 rats, and sequential morphological changes of the duodenogastric stoma and the incidence of stump cancers were studied. Serial sections around the stoma were studied with mucin stains such as paradoxical concanavalin A (Con A), galactose oxidase Schiff (GOS), and high-iron diamine-Alcian blue (HID-AB). An immunohistochemical study on cell proliferation with bromodeoxyuridine (BrdU) was also done. At week 30, pyloric gland type cells positive for Con A first appeared at the base of the intestinal crypts and the fundic glands adjacent to the anastomosis. These glands became large with time, resulting in formation of cystically dilated glands. These gland cells were partially stained with GOS, and then they retained a proliferative activity. These changes seemed to resemble "gastritis cystica profunda" in human remnant stomachs. At 50 and 80 weeks, adenocarcinomas were observed in 4 of 10 rats (40.0%) and in 16 of 21 rats (76.2%), respectively. We have noted that the early change of cystic proliferation of mucous glands resembled the so-called "ulcer associated cell lineage (UACL)" described by others, but our characteristic finding was not only pyloric but also foveolar metaplasia. This pyloric-foveolar metaplasia subsequently led to development of glands with intestinal-type goblet cells, which looked like incomplete intestinal metaplasia. This sequence was different from UACL, and very recently, we proposed a concept of "gut regenerative cell lineage (GRCL); from pyloric-foveolar to with goblet cell metaplasia in regeneration," common to all parts of the gut, and the stump cancer appeared to arise from GRCL.

Gastric emptying time, not enterogastric reflux, is related to symptoms after upper gastrointestinal/biliary surgery

BACKGROUND

It has been suggested that symptoms from bile reflux gastritis are related to the frequency and degree of enterogastric reflux (EGR).

METHODS

Patients with history of upper gastrointestinal surgery or cholecystectomy as well as control patients were studied. Presence of EGR, degree of EGR, and gastric bile emptying time were assessed and quantified via 99mTC scintillation imaging and then compared between symptomatic and asymptomatic patients.

RESULTS

Patients with vagotomy and pyloroplasty, Billroth I, Billroth II, and cholecystectomy demonstrated statistically higher degrees of EGR compared with controls. Although asymptomatic and symptomatic patients with a history of upper gastrointestinal or biliary surgery demonstrated no statistically significant differences between incidence of EGR and degree of EGR, there was a statistically significant difference in gastric emptying time.

CONCLUSIONS

Delayed gastric emptying time, not frequency or extent of EGR, was associated with the symptoms of bile reflux in patients who had previous upper gastrointestinal or biliary operations.

Changes in gastric mucosa and luminal environment during acid-suppressive therapy: a review in depth

Acid-suppressive therapy and subsequent changes in gastric mucosa and luminal environment rank highly amongst the investigated issues in gastroenterology over the past two to three decades. Herewith, we present an overview of these intragastric changes, particularly during long-term administration of acid-suppresive medication and concurrent infection with Helicobacter pylori. Current evidence indicates that: i) Long-term acid suppression facilitates the development of fundic ECL cell hyperplasia, especially in the presence of Helicobacter pylori. No neoplastic changes directly attributable to acid suppression have so far been demonstrated in humans. ii) Acid-suppressive therapy increases the risk of enteric infections. iii) Acid-suppressive therapy does not alter fat and mineral bioavailability, but may decrease the absorption of protein-bound vitamin B12. iv) Acid suppression invariably results in intragastric overgrowth of non-Helicobacter pylori bacterial species. The concurrent infection with Helicobacter pylori may promote this bacterial overgrowth and the intragastric formation of N-nitrosamines. v) Acid-suppressive therapy alters the natural course of Helicobacter pylori gastritis, transforming the antral-predominant pattern into a body-predominant pattern, which in turn may progress to body gland atrophy. The pathophysiology of this phenomenon is currently under investigation. vi) In view of the potential adverse effects of acid suppression in the presence of Helicobacter pylori, the screen-and-treat strategy is advocated for Helicobacter pylori in subjects considered for long-term treatment.

Biliary bile acid composition in gastric cancer

Bile reflux into the stomach has been considered carcinogenic. Secondary bile acids, and in particular deoxycholic acid, have been shown to act experimentally as co-carcinogens in the colon and are increased in patients with colorectal adenocarcinoma. No information is available with respect to biliary bile acid composition in patients with gastric cancer. We studied biliary bile acid composition in 11 patients with gastric cancer and 23 healthy controls. Bile acids were measured using high-performance liquid chromatography. The site of gastric cancer was the antrum in 6 patients and body in 5. There were 6 intestinal-type and 5 diffuse adenocarcinomas. Only 2 patients had Helicobacter pylori infection. Deoxycholic acid constituted 24% +/- 2% of biliary bile acid in gastric cancer patients versus 22% +/- 2% in healthy controls (NS). Similarly, no differences were found between the two groups for all other bile acids. Deoxycholic acid constituted 23% +/- 3% of biliary bile acid (NS vs. controls) in patients with antral adenocarcinoma and 25% +/- 2% (NS vs. controls) in patients with intestinal-type gastric adenocarcinoma. Gastric adenocarcinoma is not associated with an increase in the more-toxic secondary bile acids, and deoxycholic acid in particular. This reduces the importance of bile acid composition as a promotor in gastric carcinogenesis.

Biology of gastroesophageal reflux disease: pathophysiology relating to medical and surgical treatment

This chapter reviews the biology of gastroesophageal reflux disease, relating pathophysiology to medical and surgical therapy. Various definitions of the disease are presented and workable criteria are developed to identify patients with the disease. The central importance of the lower esophageal high-pressure zone as a barrier to reflux is emphasized, along with an analysis of its biomechanical alteration in disease. The composition of the refluxed gastric juice is characterized in regard to its potential for mucosal injury. Evidence is provided that cardiac-type mucosa is an acquired sequel to acid-induced squamous mucosal injury in the terminal esophagus. A hypothesis regarding the process of intestinalization of cardiac-type mucosa to form Barrett's esophagus is presented. An integrated concept of the pathophysiology of gastroesophageal reflux disease is constructed. Practical concepts regarding the treatment of gastroesophageal reflux disease are developed, based on a review of studies on the natural history of the disease and the long-term outcome of therapy.

N-Nitroso compounds, bacteria, and carcinoembryonic antigen in the gastric stump

Analyses of biochemical and microbiological parameters such as pH, N-nitroso compound (NOC) concentration, carcinoembryonic antigen (CEA) level, and total viable counts (TVCs), and identification of microorganisms were carried out on 65 fasting gastric juice samples obtained at endoscopy from 45 patients previously submitted to partial gastrectomy for benign peptic ulcer disease (23 Billroth I, 22 Billroth II/Reichel-Polya) and 20 normal controls. Biopsy specimens were taken to determine histology, the Helicobacter pylori status, and both tissue CEA immunoreactivity and level. Significantly higher mean pH values, NOC and CEA concentrations, and TVCs were found in partial gastrectomies compared with normal controls. In relation to surgical methods, higher mean pH values, NOC concentrations, TVCs, and anaerobic bacterial counts were observed in the juice of patients with Billroth II compared with Billroth I gastrectomies. Mild CEA immunoreactivity and apical CEA localization were found significantly more often in Billroth II than in Billroth I stumps. Intensive CEA immunoreactivity and cytoplasmatic localization were found significantly more often in Billroth I than in Billroth II stumps. Independent of the type of surgical reconstruction, higher mean NOC levels were recorded in patients with more severe histological changes and H. pylori infection. Higher mean CEA levels in gastric juice and tissue were detected in the gastric stumps with more severe histological changes. All these data suggest that high levels of NOCs in the gastric juice could be a cofactor in gastric stump carcinogenesis and determination of CEA level in gastric juice and tissue could be included as a very useful marker in quantifying this process.

Role of calcium in adaptive cytoprotection and cell injury induced by deoxycholate in human gastric cells

We have developed an in vitro model of adaptive cytoprotection induced by deoxycholate (DC) in human gastric cells and have shown that pretreatment with a low concentration of DC (mild irritant, 50 microM) significantly attenuates injury induced by a damaging concentration of DC (250 microM). This study was undertaken to assess the effect of the mild irritant on changes in intracellular Ca2+ and to determine if these perturbations account for its protective action. Protection conferred by the mild irritant was lost when any of its effects on intracellular Ca2+ were prevented: internal Ca2+ store release via phospholipase C and inositol 1,4, 5-trisphosphate sustained Ca2+ influx through store-operated Ca2+ channels or eventual Ca2+ efflux. We also investigated the relationship between Ca2+ accumulation and cellular injury induced by damaging concentrations of DC. In cells exposed to high concentrations of DC, sustained Ca2+ accumulation as a result of extracellular Ca2+ influx, but not transient changes in intracellular Ca2+ content, appeared to precede and induce cellular injury. We propose that the mild irritant disrupts normal Ca2+ homeostasis and that this perturbation elicits a cellular response (involving active Ca2+ efflux) that subsequently provides a protective action by limiting the magnitude of intracellular Ca2+ accumulation.

Denervation promotes the development of cancer-related lesions in the gastric remnant

Innervation of the gastric mucosa plays an important role in its defense mechanism. In a previous study, gastrectomy with denervation promoted tumorigenesis in the gastric body in rats after administration of a carcinogenic agent. In this study we investigated the induced gastric mucosal changes from the viewpoint of mucin histochemistry. Gastrectomy with denervation promoted the development of intestinal metaplasia, dysplasia, and carcinoma in the gastric body. Proliferating cell nuclear antigen labeling indexes as a marker for cell kinetics were significantly elevated in the denervated group. Analysis of mucin histochemistry by staining with paradoxical concanavalin A (PCA) and galactose oxidase-Schiff (GOS), which are markers for expression of the gastric phenotype, revealed that these mucins were positive in submucosal adenocystic proliferation and carcinoma at the anastomotic site. Conversely, in the gastric body these mucins disappeared with progression of dysplasia, and carcinoma cells contained neither PCA- nor GOS-positive mucins. These results suggest that there are two different processes of carcinogenesis in the gastric remnant, depending on the location, and that denervation of the remnant gastric mucosa promotes the development of cancer-related lesions in the gastric body.

Etiology of gastric remnant cancer with special reference to the effects of denervation of the gastric mucosa

BACKGROUND

Gastric mucosal blood flow, secretion of mucin, and renewal of the gastric mucosal cells are considered to be defensive factors against gastric mucosal injuries. These factors are regulated by the nervous system and neuropeptides. Gastrectomy may affect this regulation and induce gastric mucosal changes, such as atrophic gastritis and carcinoma. The effects of denervation of the gastric mucosa on tumorigenesis of the remnant stomach were investigated.

METHODS

Using male Wistar rats, four groups of Billroth I (B-I)gastrectomy, Billroth II (B-II) gastrectomy, and those with denervation were conducted. Subdiaphragmatic truncal vagotomy was performed in the denervated group. Thirty weeks after the operations, histologic examination and periodic acid-Schiff--Alcian blue (PAS-AB) staining of the gastric mucosa, analysis of cell kinetics of the gastric mucosa by immunohistochemistry of proliferating cell nuclear antigen, and measurement of intragastric pH, intragastric bile acid concentration, and serum gastrin levels were performed. No carcinogenic agents were given.

RESULTS

The B-I group showed no remarkable gastric mucosal changes, but B-I with denervation showed a significant increase in the development of tumor (67%) and carcinoma (42%). In the B-II groups, the denervation induced a significant increase in tumorigenesis, from 22% to 58%. Analysis of cell kinetics revealed a significant increase of labeling index in those groups that developed tumors. PAS-AB staining showed a decrease of PAS positive mucin but an increase of acidic mucin-producing cells in the denervated groups, suggesting an increase in the number of immature cells that are more susceptible to atrophic gastritis and carcinoma. There was no close relationship between tumorigenesis and intragastric pH, intragastric bile acid concentration, or serum gastrin levels.

CONCLUSIONS

After gastrectomy, not only duodenogastric reflux, but also the denervation of the gastric mucosa play an important role in the etiology of gastric remnant cancer.

Pathophysiological effects of long-term acid suppression in man

A critical evaluation has been made of the available evidence in man of the effects of prolonged low acid states on the structure and function of the stomach. Various human models have been examined. 1. Ageing does not affect acid output from the normal male stomach, and there may be an increase in women. With progressive atrophy of the corpus mucosa, which is more frequent and rapid in patients with gastric ulcer, there is an associated loss of secretory function. Chronic gastritis and atrophy are the most important age-related changes, which in many cultures are hypothesized to develop via a prior Helicobacter pylori-related gastritis. However, H. pylori colonization of the mucosa decreases with increasing grades of gastric atrophy probably because intestinal metaplasia provides a hostile environment. Atrophy and intestinal metaplasia are associated with precancerous lesions and gastric cancer. Apparent hyperplasia of the gastric argyrophil endocrine cells is a common and spontaneous phenomenon in patients with atrophic gastritis, which in part may be related to the preferential loss of nonendocrine cells. 2. Pernicious anemia is associated with a complete lack of acid production, marked hypergastrinemia, and endocrine cell hyperplasia in the majority of patients. ECL-cell carcinoids and gastric cancer occur with a prevalence of 3-7%, and endoscopic surveillance in routine clinical practice is not warranted. 3. Gastric ECL-cell carcinoids are rare events that have been described in association with two diseases in man, pernicious anemia and Zollinger-Ellison syndrome as part of multiple endocrine neoplasia syndrome type I, and usually relate to marked hypergastrinemia and the presence of chronic atrophic gastritis with gastric antibodies or a genetic defect rather than the presence or absence of acid. Regression or disappearance of ECL-cell carcinoids, either spontaneously or after removal of the gastrin drive, has been recorded. Lymph node, and rarely hepatic, metastases are documented but death in these cases has been anecdotal. 4. Therapy with H2 antagonists may result in up to a twofold rise in serum gastrin levels but in man no endocrine cell hyperplasia has been recorded. However, the data for H2 antagonists on these aspects are very limited. There is no drug-related risk of gastric or esophageal cancer, although the incidence of the latter may be raised. Long-term treatment with omeprazole is associated with a two- to fourfold increase in gastrin levels over baseline values in one third of patients and apparent endocrine cell hyperplasia in 7% of cases overall.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinogenesis after remote peptic ulcer surgery: the long-term prognosis of partial gastrectomy

Remote partial gastrectomy for benign disease is a premalignant condition. The overall risk of gastric stump cancer is approximately a twofold increase, but patients more than 20-25 years postoperatively may have a four- to fivefold increased risk, compared to the age- and sex-matched general population. The duration of postoperative interval is the most important risk factor. For the first 10 years after initial surgery, gastric cancer risk may be reduced due to the removal of the most cancer-prone distal part of the stomach, but thereafter there is a rapid increase of the relative risk. The etiology and precise mechanism of carcinogenesis is unknown, but the time relationship with surgery suggests that the anatomical alterations induced by the operation must be important. Hypochlorhydria, reflux, diminished gastrin production, bacterial proliferation, and nitrosation are the putative contributing factors. In addition, smoking appears to contribute to a generalized cancer mortality and decreased life expectancy after peptic ulcer surgery. Digestive tract cancers other than the gastric ones which show an increased risk after peptic ulcer surgery are pancreatic and biliary tract cancers. Premalignant and precursor lesions occur more frequently in the gastric remnant after peptic ulcer surgery and endoscopic bioptic screening can detect early stump cancers at a curable stage. Large-scale screening programs of post-gastrectomy patients are nevertheless not recommended, and surveillance appears not justified.

Nucleolar organizing regions in the operated rat stomach: relationship to metaplasia, dysplasia and carcinoma

This study investigated the role of duodenogastric reflux in rats after antecolic gastrojejunostomy. At the end of the study, adenocarcinoma was present in 43 per cent, dysplasia in 14 per cent and intestinal metaplasia in 43 per cent of animals. No such changes were found in control rats. A technique for silver staining nucleolar organizing regions (AgNORs) was applied to these lesions and to the control group. The AgNOR count gradually increased from normal gastric mucosa to carcinoma. This technique demonstrated differences in AgNOR count between normal mucosa and other lesions (adenocarcinoma, dysplasia, intestinal metaplasia) (P < 0.001). There was, however, considerable overlap among adenocarcinoma, dysplasia and metaplasia (P > 0.1).

Implications of sustained suppression of gastric acid secretion

The implications of profound and sustained suppression of acid secretion are of increasing concern. Short-term inhibition of acid secretion by H2-receptor blockade or proton pump inhibition alters the gastric luminal flora and increases the risk of nosocomial pneumonia in critically ill patients who are receiving prophylaxis for stress gastritis. Long-term suppression alters gut flora, carcinogen levels in the gastric lumen, and the hormonal milieu, leading to proliferative changes in the fundic mucosa. Previous reports have noted a significant incidence of gastric malignancies in the achlorhydric environment of atrophic gastritis and pernicious anemia. Concern has also been expressed regarding the possibility of gastric neoplasia that arises after vagotomy and distal gastrectomy. The exact risk of gastric epithelial and endocrine hyperplasia or neoplasia in patients receiving potent antisecretory agents is not yet known, but such risks cannot be dismissed until long-term follow-up studies are available. The relationship between sustained suppression of acid secretion and the proliferation of epithelial and endocrine elements may provide insight into processes that regulate replication and growth of cells in the gastric mucosa.

The risk of cancer at all sites following gastric operation for benign disease. A cohort study of 4,224 patients

This report represents the results of a historical cohort analysis of 3,360 males and 864 females who had a gastric resection or gastroenterostomy for benign disease between 1990 and 1969. Within the period 1970 to 1988 the cohort was cross-checked with the data files at the Cancer Registry of Norway to identify the patients in whom cancer had been diagnosed. When analyzed according to cancer sites, increased risk was recorded for the oropharynx, stomach, colon, pancreas, liver, biliary tract, larynx, lungs, urinary bladder and non--melanomatous cancers of the skin in males. In females, increased risk was only observed for the oropharynx, but was close to a statistically significant level also for cancer of the stomach. A lower number of tumors of the central nervous system than expected was observed in both males and females. The increased risk of cancer of the lungs, larynx and urinary bladder in males can be regarded as evidence of the high prevalence of smokers in the cohort. We suggest that the increased risk of cancer of digestive organs is mainly related to life-style factors, particularly tobacco-specific nitrosamines whose effect is enhanced by surgical sequelae.

Occurrence of non-gastric cancer in the digestive tract after remote partial gastrectomy: analysis of an Amsterdam cohort

If peptic ulcer surgery favors the formation of carcinogenic N-nitroso compounds in the gastric remnant, an increased risk of cancer at sites in the gastrointestinal tract distant from the stomach might be predicted. To estimate the risk of carcinomas in the digestive tract, other than the stomach, occurring after partial gastrectomy, we analyzed an Amsterdam cohort of 2,633 post-gastrectomy patients operated on for benign disease between 1931 and 1960. Mortality in the study population was compared with the general Dutch population through person-year analysis. An excess mortality of biliary tract cancer (O/E:2.64; CL:1.32-4.72; p less than 0.01) and pancreatic cancer (O/E:1.65; CL:1.06-2.44; p less than 0.05) was found in males more than 5 years after surgery; females showed only an increased risk of pancreatic cancer in the first 5 years postoperatively (O/E:15.33; CL:1.85-55.43; p less than 0.01), probably due to misdiagnosis. All other non-gastric sites of the digestive tract carried no increased risk for cancer. In males, mortality due to colorectal cancer more than 5 years post-operatively was significantly decreased (O/E:0.58; CL 0.34-0.92; p less than 0.01). The excess mortality of biliary-tract and pancreatic cancer in males, which increases with the duration of post-operative interval, is consistent with a dose-response phenomenon. This study therefore supports the hypothesis that carcinogens are not only locally activated in the gastric remnant, but are hepatically excreted and initiate cancer in the biliary tree and pancreatic duct. Further exploration of this mechanism of carcinogenesis is warranted, since it may also explain the pathogenesis of pancreatic and biliary cancers in patients without gastrectomy.

New technique for analysing conjugated bile acids in gastric juice

A new technique of high performance liquid chromatography (HPLC) was developed for the analysis of conjugated bile acids in gastric juice. The assay is rapid, sensitive, and highly specific for bile acid conjugates over the range 30-10,000 mumol/l and is not affected by the presence of food. Ten patients with a variety of common upper gastrointestinal disorders underwent continuous gastric aspiration for 16 hours, including a fasting, post-prandial, and nocturnal period, and aliquots of aspirates were analysed every two hours by the HPLC technique for the six most prevalent bile acid conjugates present in human hepatic bile. Intragastric bile acid concentrations were lowest in the post-prandial period and highest in the early hours of the morning. Conjugated bile acid proportions, or profiles, varied considerably from patient to patient, but tended to remain uniform over time in individual patients. It is concluded that HPLC is superior to enzymatic techniques for the analysis of conjugated bile acids in the upper gastrointestinal tract.

Experimental colonic carcinogenesis after gastric surgery

Peptic ulcer surgery may predispose to the subsequent development of colorectal cancer. This experimental study has investigated the effects of gastric operations on colonic cell proliferation, bile acid excretion and carcinogenesis. Male Sprague-Dawley rats (n = 105) underwent sham operation, Pólya partial gastrectomy or vagotomy and pyloroplasty. The carcinogen azoxymethane was administered weekly for 6 weeks thereafter (total dose 60 mg kg-1). When the animals were killed 24 weeks after operation, colons were examined for mucosal mass, crypt cell production rate (CCPR) and tumour yield; faeces were assayed for contents of neutral steroids and bile acids (both total and individual). Morphometric indices and mucosal DNA content were similar in all three groups. Pólya gastrectomy reduced: (1) CCPR throughout the colon (by 42-65 per cent, P less than 0.002); (2) the number of rats with colorectal tumours (26 per cent versus 63 per cent, P less than 0.05); (3) faecal levels of neutral steroids and bile acids, notably hyodeoxycholic acid (P less than 0.01). Although vagotomy and pyloroplasty increased caecal CCPR, there were no consistent differences in faecal steroids and no alteration in tumour yield after the operation. These results fail to support clinical studies suggesting that gastric surgery predisposes to colonic carcinogenesis. Indeed, Pólya partial gastrectomy exerts a protective effect, probably by inhibiting colonic cell proliferation.

A prospective cohort study on the development of colorectal cancer after gastrectomy

A prospective cohort study was conducted to examine whether an association exists between gastric surgery and the subsequent development of colorectal carcinoma. One thousand nine hundred twenty-seven patients (1316 men and 611 women) who had undergone curative gastrectomy for gastroduodenal diseases in the First Department of Surgery, Tottori University Hospital, during the 18-year period from 1964 to 1981, were followed to determine the incidence of the development of large-bowel carcinoma after gastric surgery. The age-, sex-, and calendar-specific population at risk was calculated by the person-years method. The observed number of colorectal cancers after gastrectomy was 19 (15 men, 4 women) compared with 9.69 expected carcinomas. The difference between the observed and expected numbers was statistically significant. The authors believe that patients with previous gastrectomy are at high risk for colorectal carcinoma.

Bile reflux and the gastric mucosa: an experimental ferret model

To study the effects of chronic bile reflux on the mammalian gastric mucosa, the ferret model was chosen for its practical aptitude and for its similarity to human gastric anatomy and physiology. A technique was first perfected for endoscopically directed gastric mucosal biopsy in the ferret. Subsequently, a surgical model of maximal enterogastric reflux (MR) and a control model of minimal reflux or "nonreflux" (NR) were developed. A stable population of 9 MR and 9 NR ferrets surviving 1-3 years has been established. All 18 animals, plus 6 nonoperative control animals, have undergone multiple repeat endoscopy and gastric biopsy without complication. The surgical and endoscopic techniques, with preliminary findings, are described.

Effect of bile salts on carbonic anhydrase from rat and human gastric mucosa

Gastric carbonic anhydrase (CA) is believed to play an important role related to cytoprotection, and duodenogastric reflux of bile salts (BS) is suspected of having a causal role in many pathologic conditions. Thus, we decided to investigate the effect of free and conjugated BS on human and rat gastric CA activity. Cholate exerted the most potent inhibitory activity on both human (I50 = 2.24 mM) and rat (I50 = 1.68 mM) gastric CA, followed by glycochenodeoxycholate and taurocholate (I50 = 6.90 mM and 13.67 mM on rat gastric CA). Human and rat whole bile produced 10-90% and 20-40% inhibition of gastric CA of the same species. Since the concentrations of free and conjugated BS tested in this study can be found in the postgastrectomized stomach, our data suggest that inhibition of gastric CA might be one mechanism contributing to the gastric mucosa damage caused by BS refluxing into the stomach after gastric surgery.

Gastric juice factors after Roux-Y reconstruction compared with Billroth II partial gastrectomy

Gastric juice was studied in five patients after Billroth II partial gastrectomy, in six patients after Roux-Y reconstruction, and in eight healthy control subjects. Juice was obtained over a 24 hour period by hourly nasogastric aspiration prior to measurement of pH, total and stable N nitrosocompounds, nitrites, bile acids (total and free), and bacterial count. Large variations in almost all compounds were seen during the 24 hour period in individual patients, and in addition, there were large variations between patients within the clinical groups. The gastric juice pH concentration was higher in the Billroth II group, as was the bacterial flora count (median 3 X 10(6) organisms/ml). Although Roux-Y bile diversion reduced the exposure to bile acids, it did not prevent it, and bacterial proliferation was increased (1 X 10(7) organisms/ml). No significant differences or sizeable trends were seen in N nitrosocompounds or nitrite concentrations.

Pancreaticoduodenal secretions and the genesis of gastric stump carcinoma in the rat

This study was designed to investigate the role of duodenogastric reflux in the genesis of gastric stump carcinoma in the rat. Carcinoma was not detected in any of the 11 control animals and in only one animal with a Roux diversion. In contrast seven of 12 animals with duodenogastric reflux developed carcinoma (p less than 0.01 and p less than 0.05 respectively). In order to determine which fraction of the reflux was implicated in the malignant process, animals with reflux of bile alone or pancreaticoduodenal secretions alone were studied. No carcinomas were found in 11 animals with bile reflux alone, but carcinoma was detected in 10 of 14 animals with reflux of pancreaticoduodenal secretions (p less than 0.01). The findings confirm that duodenogastric reflux is an important factor in the malignant process, and imply that the pancreaticoduodenal component, not bile is responsible.

Bile acid concentrations in the refluxate of patients with reflux oesophagitis

Although reflux of bile acids has been implicated in the pathogenesis of reflux oesophagitis, attempts to document this in vivo have failed to detect more than trace amounts of bile acid in the oesophagus. To determine the bile acid composition of oesophageal refluxate, 45 patients with abnormal acid gastro-oesophageal reflux with oesophagitis and 10 controls had a size 14 Fr Salem sump tube positioned 5 cm above the lower oesophageal sphincter. Oesophageal contents were continuously aspirated and collected in aliquots every 2 h over 16 h. Fasting, postprandial, upright and supine (nocturnal) periods were assessed and total conjugated bile acids were measured by high pressure liquid chromatography with a sensitivity of 8 mumol/l. Conjugated bile acids were detected in 2 of 10 controls (maximum 40 mumol/l) and in 39 of 45 patients (87 per cent). Eleven patients had peak conjugated bile acid levels greater than 200 mumol/l, and these levels occurred exclusively during the supine (nocturnal) period. Median conjugated bile acid levels during daytime reflux were less than 20 mumol/l which was significantly lower than during nocturnal reflux (median 51 mumol/l, P less than 0.001). Conjugated bile acids are detected in the oesophagus of most patients with oesophagitis and may play a role in the pathogenesis of oesophagitis in some patients with nocturnal gastro-oesophageal reflux.

Chronic atrophic gastritis and risk of N-nitroso compounds carcinogenesis

Chronic atrophic gastritis is considered a precancerous condition for carcinoma of the stomach. To evaluate the correlation between progressive alterations in the mucosa and gastric juice microenvironmental factors, retained involved on N-nitroso compounds carcinogenesis, detailed analyses of biochemical and microbiological parameters such as pH, total viable counts (TVC), nitrate reductase positive bacterial counts (NRPBC), nitrite (NO2-) and thiocyanate (SNC-) levels, were carried out on 56 fasting gastric juices samples obtained at endoscopy from 28 patients with chronic atrophic gastritis (CAG), 14 with gastric cancers (GC), and 14 normal controls (NC). The mean values of pH, nitrite, TVC, and NRPBC were significantly lower in the juices of NC than in those of CAG and GC patients. Furthermore, the mean levels of the same parameters were higher in GC than in CAG juices. No significant difference was found in the three groups for SCN- level which principally resulted influenced by smoke habit. The 28 patients with CAG were subdivided into two groups (Group A = Diffuse chronic atrophic gastritis--DCAG; Group B = Multifocal chronic atrophic gastritis--MCAG) according to the involvement of gastric corpus and fundus besides antrum by a process of mucosal atrophy. The mean levels of pH, nitrite, TVC, and NRPBC were significantly higher in MCAG than in normal controls but statistically lower in reference to DCAG and cancers. In these two groups no difference was found for the same variables. The percentage of contaminated juices was higher for DCAG and cancers in respect to MCAG but no difference was found between DCAG and neoplastic stomachs. The results of this study suggest that the DCAG could be considered as the chronic atrophic gastritis type more exposed to the risk of N-nitroso compounds carcinogenesis.

Risk of colorectal cancer after surgery for benign peptic ulceration

A historical prospective cohort study has been conducted to determine the incidence of colorectal carcinoma following gastric surgery for benign peptic ulcer disease. A total of 4131 patients from 53 hospitals in the western part of Denmark were operated upon for gastric or duodenal ulcer from 1955 to 1960 inclusive. After exclusion of patients who were diagnosed as having a primary cancer before the ulcer operation and 0.5 per cent of the patients whose present status could not be defined, 2975 men and 943 women survived more than one month after the operation and thus formed the cohort of the study. They were followed up to their death or the end of the year 1982. Eighty-four colorectal carcinomas were observed against the expected 85.9. There was no significant difference between observed or expected number of cancers neither among men nor women.

Inhibition of intestinal carcinogenesis by dietary supplementation with calcium

Dietary supplementation with calcium reduces colonic crypt cell production rates in both normal and hyperplastic mucosa. Calcium can bind intraluminally with bile salts and fatty acids thus reducing their mitogenic effect. The protective role of oral calcium on intestinal carcinogenesis (induced by azoxymethane) was tested in 60 male Sprague-Dawley rats submitted to either 80 per cent mid jejuno-ileal resection (n = 30) or jejunal transection (n = 30). Half the rats in each group received calcium lactate 24 g/l added to their drinking water. Rats were killed 25-27 weeks postoperatively. Enterectomy increased colonic tumour yield by 60-106 per cent (P = 0.002-0.005) and duodenal tumour yield by 70-86 per cent. Calcium abolished this effect at both sites, halving intestinal tumour yields in rats with both transection and resection (P less than 0.05). Doubling the dietary intake of calcium inhibits experimental carcinogenesis.

Regurgitant bile acids and mucosal injury of the gastric remnant after partial gastrectomy

Three groups, each consisting of seven patients who had undergone either Billroth I, Billroth II, or pylorus-preserving gastrectomies, were evaluated more than 18 months postoperatively in terms of concentration and amount of bile acids in the gastric aspirate and histologic changes in the gastric remnant mucosa. Concentrations of bile acids were determined by gas chromatography and mucosal specimens were obtained by endoscopic biopsy. The total bile acid concentration and all of the individual fractional bile acid levels, whether free or conjugated, were significantly higher in the Billroth II group than in the other two groups. The amount of gastric aspirate was also highest in the Billroth II group. Endoscopic biopsy revealed glandular dysplasia to be predominantly in the Billroth II group. The presence of bile acids in the gastric remnant may contribute to mucosal injury, possibly leading to cancer in the gastric remnant, especially after the Billroth II operation.

Effect of duodenogastric reflux on gastric mucosal proliferation after gastric surgery

The effect of duodenogastric reflux on cell proliferation and mucosal mass in the stomach was studied. Male Wistar rats (n = 118) were submitted to Polya partial gastrectomy, partial gastrectomy with Roux-en-Y diversion of bile, total duodenogastric reflux or handling of the stomach alone (sham operation). Following oral administration of the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine for 6 months, animals were killed 6, 9 or 12 months postoperatively and their stomachs were examined for crypt cell production rate and mucosal DNA content. Compared with shams, crypt cell production rate was more than twice as high in the gastric remnant 12 months after Polya partial gastrectomy (P less than 0.001) and median DNA content was 31 per cent greater (P = 0.05). After total duodenogastric reflux, DNA content was 62 per cent greater than in shams (P = 0.02), while Roux-en-Y diversion reduced crypt cell production rate by 65 per cent (P less than 0.001). Only Polya gastrectomy increased the number of rats developing gastric carcinomas (9 versus 2 shams; P less than 0.05). Increased mucosal cell proliferation in rats with duodenogastric reflux may help to explain the development of gastric stump cancer.

Gastric cancer following highly selective vagotomy

A case of gastric cancer occurring seven years after a highly selective vagotomy is described. This operation may not be the appropriate choice for the surgical treatment of gastric ulcers and H2 blockers should be used with caution in these patients.

Duodenogastric reflux in rat gastric carcinoma

This study investigated the role of long-term reflux of bile and/or pancreaticoduodenal secretions in the genesis of gastric carcinoma in the rat. Adenocarcinoma, dysplasia and adenocystic proliferation were found only in those animals with reflux of pancreaticoduodenal secretions alone or in combination with bile. No such changes were found in control animals with no reflux or animals with bile reflux alone. The differences in incidence of adenocarcinoma were significant. The presence of adenocarcinoma was not related to the pH of the intragastric contents or to the bacterial flora. This suggests that duodenogastric reflux is implicated in gastric carcinogenesis in the rat and that pancreaticoduodenal secretions rather than bile are responsible.

The microflora of the gastric juice after Billroth I and Billroth II partial gastrectomy

Detailed analyses of biochemical and microbiological variables such as pH, nitrite concentration, total viable counts (TVC), nitrate reductase-positive bacterial counts (NRPBC), and identification of microorganisms were carried out on 76 fasting gastric juice samples obtained at endoscopy from 64 patients previously submitted to partial gastrectomy (22 end-to-end Billroth I, 42 Billroth II/Reichel-Polya) and from 12 normal controls. Samples from normal controls were sterile, but bacteria were detected in the juice from all the operated patients. Significantly higher mean pH values and nitrite levels (p less than 0.001) were found in partial gastrectomies than in normal controls. In relation to surgical methods, higher mean pH values (p less than 0.005), nitrite levels (p less than 0.01), TVC (p less than 0.01), and NRPBC (p less than 0.005) were observed in the juice of patients with Billroth II as compared with Billroth I gastrectomies. Anaerobic bacteria, typical of faecal flora, and particularly Escherichia coli (p less than 0.05) characterized Billroth II samples. All these data suggest that the presence of bacteria in the gastric juice of gastroresected patients can be considered a risk factor of gastric neoplasia and that the type of operation used for the reconstruction of digestive continuity may influence the magnitude of this risk.