The Results of Pancreatic Resections and Long-Term Survival for Pancreatic Ductal Adenocarcinoma: A Single-Institution Experience

OBJECTIVES

Since the early 1990s, low long-term survival rates following pancreatic surgery for pancreatic ductal adenocarcinoma have challenged us to improve treatment. In this series, we aim to show improved survival from pancreatic ductal adenocarcinoma during the era of centralized pancreatic surgery.

METHODS

Analysis of all pancreatic resections performed at Helsinki University Hospital and survival of pancreatic ductal adenocarcinoma patients during 2000-2013 were included. Post-operative complications such as fistulas, reoperations, and mortality rates were recorded. Patient and tumor characteristics were compared with survival data.

RESULTS

Of the 853 patients undergoing pancreatic surgery, 581 (68%) were pancreaticoduodenectomies, 195 (21%) distal resections, 28 (3%) total pancreatectomies, and 49 (6%) other procedures. Mortality after pancreaticoduodenectomy was 2.1%. The clinically relevant B/C fistula rate was 7% after pancreaticoduodenectomy and 13% after distal resection, and the re-operation rate was 5%. The 5- and 10-year survival rates for pancreatic ductal adenocarcinoma were 22% and 14%; for T1-2, N0 and R0 tumors, the corresponding survival rates were 49% and 31%. Carbohydrate antigen 19-9 >75 kU/L, carcinoembryonic antigen >5 µg/L, N1, lymph-node ratio >20%, R1, and lack of adjuvant therapy were independent risk factors for decreased survival.

CONCLUSION

After centralization of pancreatic surgery in southern Finland, we have managed to enable pancreatic ductal adenocarcinoma patients to survive markedly longer than in the early 1990s. Based on a 1.7-million population in our clinic, mortality rates are equal to those of other high-volume centers and long-term survival rates for pancreatic ductal adenocarcinoma have now risen to some of the highest reported.

Clinical Outcome after D1 vs D2–3 Gastrectomy for Treatment of Gastric Cancer

Background:

Clinical benefit from extended lymphadenectomy for gastric cancer remains controversial as a considerable variation exists between results of different studies.

Methods:

562 patients were treated at HUCH between 1987–2003, whereof 223 underwent gastrectomy with curative intent. Of these, 114 patients underwent subtotal/total gastrectomy with D1 (standard) lymphadenectomy and 109 patients had D2–3 (extended) lymph node dissection. The clinical outcome of these patients was analysed retrospectively.

Results:

The incidence of surgical complications was 33.0% in D2–3 and 16.8% in D1 lymphadenectomy groups (p = 0.008). Abscess was the most common complication (11.0%) among D2–3 operated patients and haemorrhage (4.4%) in D1 group. Hospital mortality was 3.7% in D2–3 and 1.8% in D1 group (p = 0.438). The only statistically significant factor influencing the rate of complications was D2–3 lymphadenectomy (OR 2.620, 95% C.I. 1.375 to 4.991). D2–3 was associated with a longer postoperative hospital stay and operation time, greater blood loss and increased need for blood transfusions compared to D1. The 5-year survival was not statistically different between lymphadenectomy groups.

Conclusion:

It is justified to perform a D2–3 gastrectomy in Europe with a acceptable postoperative mortality but with a significant morbidity. Further studies are needed to assess the value of extended lymphadenectomy in gastric cancer

Preoperative biliary decompression preceding pancreaticoduodenectomy with plastic or self-expandable metallic stent

BACKGROUND AND AIMS

The rainage (PBD) prior to pancreaticoduodenectomy (PD) is controversial. If PBD is required, large bore self-expandable metallic stents (SEMS) are thought to maintain better drainage and have fewer postoperative complications than plastic stents. The confirming evidence is scarce. The aim of the study was to compare outcomes of surgery in patients who underwent PBD with SEMS or plastic stents deployed at endoscopic retrograde cholangiopancreatography (ERCP).

MATERIAL AND METHODS

This is a retrospective study of 366 patients having had PD during 2000-2009. Preceding endoscopic PBD was performed in 191 patients and nine had had percutaneous transhepatic drainage (PTD). At the time of operation, 163 patients had a plastic stent and 28 had SEMS. Due to stent exchanges, 176 plastic stents and 29 SEMS were placed in all.

RESULTS AND CONCLUSIONS

The stent failure rate was 7.4% for plastic stents and 3.4% for SEMS (p = 0.697). A bilirubin level under 50 µmol/L was reached by 80% of the patients with plastic stents and by 61% of the patients with SEMS (p = 0.058). A postoperative infection complication and/or a pancreatic fistula was found in 26% while using plastic stents and in 25% using SEMS (p = 1.000). In unstented patients with biliary obstruction, the bile juice was sterile significantly more often than in endoscopically stented patients (100% vs 1%, p < 0.001). When the stented and unstented patients were compared regarding postoperative infection complications, there was no significant difference between the groups (p = 0.365). Plastic stents did not differ from SEMS regarding the stent failure rate, bilirubin level decrease, amount of bacteria in the bile juice, or postoperative complications when used for PBD. The significantly higher price of SEMS suggests their use in selected cases only.

Surveillance and treatment of duodenal adenomatosis in familial adenomatous polyposis

BACKGROUND AND STUDY AIMS

Patients with familial adenomatous polyposis (FAP) are at increased risk for duodenal cancer whereas colorectal cancer is largely prevented by prophylactic colectomy. We analyzed the results of endoscopic surveillance and different treatment modalities of duodenal adenomatosis in patients with FAP.

PATIENTS AND METHODS

Data on endoscopies, histopathological examinations, and surgical therapies were collected from the medical histories of 129 patients with FAP. The cumulative incidences of duodenal adenomatosis and severe dysplasia and cancer were calculated using Kaplan-Meier analysis.

RESULTS

By the age of 60 years, the cumulative incidence was 80% for any adenomatosis and 23% for severe dysplasia or cancer. Duodenal cancer was observed in six patients (4.7%). Fifteen endoscopic excisions in 14 patients, and 19 open duodenotomies in 17 patients were carried out. Later, pancreaticoduodenectomy was undertaken in six (35.3%) of these 17 patients. Altogether, 12 patients (9.3%) underwent pancreaticoduodenectomy. Except for one patient, the indication for surgery was based on follow-up endoscopies, and none of these patients died of duodenal cancer. No postoperative deaths occurred. Seven patients (58.3%) had major complications, four (33.3%) of which were surgical.

CONCLUSIONS

The high incidence of severe dysplasia and cancer in duodenal polyps suggests that endoscopic surveillance is essential. Endoscopic polypectomies under sedation anesthesia have partly replaced open duodenotomies. High-risk patients with Spigelman IV adenomatosis or adenomas with persisting severe dysplasia should undergo surgery with pylorus-preserving pancreaticoduodenectomy before invasive cancer develops.

A common variant in PNPLA3, which encodes adiponutrin, is associated with liver fat content in humans

AIMS/HYPOTHESIS

It has recently been suggested that the rs738409 G allele in PNPLA3, which encodes adiponutrin, is strongly associated with increased liver fat content in three different ethnic groups. The aims of the present study were as follows: (1) to try to replicate these findings in European individuals with quantitative measures of hepatic fat content; (2) to study whether the polymorphism influences hepatic and adipose tissue insulin sensitivity; and (3) to investigate whether PNPLA3 expression is altered in the human fatty liver.

METHODS

We genotyped 291 Finnish individuals in whom liver fat had been measured using proton magnetic resonance spectroscopy. Hepatic PNPLA3 expression was measured in 32 participants. Hepatic and adipose tissue insulin sensitivities were measured using a euglycaemic-hyperinsulinaemic (insulin infusion 0.3 mU kg(-1) min(-1)) clamp technique combined with infusion of [3-(3)H]glucose in 109 participants.

RESULTS

The rs738409 G allele in PNPLA3 was associated with increased quantitative measures of liver fat content (p = 0.011) and serum aspartate aminotransferase concentrations (p = 0.002) independently of age, sex and BMI. Fasting serum insulin and hepatic and adipose tissue insulin sensitivity were related to liver fat content independently of genotype status. PNPLA3 mRNA expression in the liver was positively related to obesity (r = 0.62, p < 0.0001) and to liver fat content (r = 0.58, p = 0.025) in participants who were not morbidly obese (BMI < 40 kg/m(2)).

CONCLUSIONS/INTERPRETATION

A common variant in PNPLA3 increases the risk of hepatic steatosis in humans.

Ethanol induces volume changes and gap junction closure via intracellular Ca2+ signalling pathway in cultured rabbit gastric epithelial cells

BACKGROUND

Ethanol is a well-established 'barrier breaker' in gastric mucosa, but its effects at cellular level remain to be detailed.

METHODS

Gastric epithelial cells were isolated from rabbits and cultured to monolayers. Intracellular calcium was measured spectrofluorometrically with fura-2. The patency of gap junctions was assessed by photobleaching a small area of 5-carboxyfluorescein loaded monolayer and measuring recovery of fluorescence. For cell volume measurements the change in fluorescence intensity was followed in calcein-loaded monolayers with a confocal microscope.

RESULTS

Intracellular calcium concentration was increased from 65 +/- 9 to 140 +/- 17 nM; recovery of fluorescence signal after photobleaching was diminished from 53% +/- 11% to 9% +/- 3%; and cell volume was decreased significantly after 10 min exposure to 5% (vol/vol) ethanol. This volume decrease was prevented with serosal application of the potassium channel blocker, quinine, or by blocking the intracellular calcium signalling pathway with the intracellular calcium-chelating agent BAPTA. This suggests that luminal ethanol opens the basolateral calcium-dependent potassium selective channels via calcium signalling pathway, with resultant shrinkage of the cell.

CONCLUSION

Intracellular calcium concentration is increased, gap junctions are closed and cell volume is decreased after exposure to 5% ethanol. Since gap junctions are known to be calcium gated, it is likely that their closure is secondary to the elevated cytosolic calcium in ethanol injured cells. This may have a protective function by limiting intercellular spread of impending cell injury. The opening of the basolateral potassium channel probably underlies the ethanol-induced cell shrinkage and might contribute to the ethanol-provoked epithelial damage.

Nitric oxide donors retard wound healing in cultured rabbit gastric epithelial cell monolayers

Effects of nitric oxide (NO) on gastric wound healing were investigated in primary rabbit gastric epithelial cell cultures. We analyzed the speed of cell migration, proliferation, and apoptosis after creating a round wound on the cell cultures. The monolayers were incubated with or without the NO donor sodium nitroprusside, oxatriazolimine 1,2,3,4-oxatriazolium, 5amino-3-(3,4-dichlorophenylchloride), or the peroxynitrite generator 3-morpholinosydnomine-N-ethylcarbamide. The possible role of cGMP as a second messenger of NO was investigated with 8-bromo-cGMP. The role of O2(-*) was evaluated using diethyldithiocarbamate and pyrogallol. The effects of superoxide dismutase and allopurinol were also investigated. NO inhibited the speed of cell migration and proliferation and induced cell apoptosis in a dose- and time-dependent manner. The effects were augmented with O2(-*) generators and ameliorated by O2-(8) scavengers, whereas cGMP had no significant effect on wound healing. NO donors retard gastric wound healing by inhibiting migration and proliferation and inducing cell apoptosis. These effects do not seem to be mediated via cGMP, but O2(-*). or peroxynitrites may be involved.

In vivo glucose-stimulated amylin secretion is increased in nondiabetic patients with pancreatic cancer

The incidence of diabetes is increased in patients with pancreatic cancer, but the mechanisms underlying this association are not clear. Alterations in beta-cell function, such as formation of amyloid from excessive production of amylin and reduced expression of GLUT2, have been suggested to be possible mechanisms. We compared in vivo secretory responses of amylin and insulin (n = 37) and expression of GLUT2 in pancreata (n = 10) obtained at surgery between diabetic and nondiabetic patients with and without pancreatic tumors. Fourteen had pancreatic adenocarcinoma, 7 had diabetes (duration 6 +/- 3 years) and a pancreatic tumor, 8 had type 2 diabetes (duration 6 +/- 2 years), and 8 were normal subjects. First (0 to 10 minutes) and second (10 to 120 minutes) phase insulin and amylin secretion were characterized using the hyperglycemic clamp technique. Both amylin and insulin concentrations followed a biphasic pattern in nondiabetic subjects. In nondiabetic patients with pancreatic cancer, total, as well as nonglycosylated amylin concentrations, were increased compared with nondiabetic subjects without pancreatic cancer. Both first- and second-phase plasma amylin and serum immunoreactive insulin concentrations were low in all patients with diabetes, ie, both in type 2 diabetes and in those patients with diabetes and pancreatic tumors. At surgery, specimens were obtained for characterization of GLUT2 expression in beta cells, which was unaltered in nondiabetic (n = 7) and diabetic (n = 3) patients. Amyloid staining was similarly negative in diabetic and nondiabetic pancreata independent of pancreatic carcinoma. In conclusion, plasma amylin, but not insulin concentrations, are increased in nondiabetic patients with pancreatic cancer, but low in all patients with diabetes. These data support the potential of using an increase in the ratio of circulating amylin to insulin as a marker for pancreatic cancer in nondiabetic patients.

HCl causes less intracellular acidification in Necturus gastric mucosa surface epithelial cells than other acids

Luminal acid causes intracellular acidification in the gastric epithelium, but the mechanism by which H(+) enters surface cells remains obscure. This study addressed the problem by assessing how different acids affect intracellular pH in gastric surface cells. Isolated Necturus maculosus antral mucosa was exposed to HCl, HNO(3), H(2)SO(4), and H(3)PO(4) at pH 2.30. Intracellular pH was measured with microelectrodes. The physicochemical interaction of a synthetic model of gastric phospholipids with the different acids was studied using Langmuir film balance. Exposure to luminal HNO(3), H(2)SO(4), or H(3)PO(4) caused significantly larger intracellular acidification than exposure to HCl. The degree of acidification was not dependent on the valence or nature of the anionic counterion of the acid but significantly correlated with the amount of molecular acid. By Langmuir film balance, subphases acidified with HNO(3), H(2)SO(4), or H(3)PO(4) caused more close packing of phospholipid molecules than those acidified with HCl, possibly allowing hydrogen bonding between head groups to facilitate H(+) movement across the phospholipid membrane. HCl causes significantly less intracellular acidification in gastric epithelium than HNO(3), H(2)SO(4), or H(3)PO(4). This may be caused by the lower amount of molecular HCl in solution and possible hydrogen bonding between the head groups of phospholipid molecules and the other acids.

Quantitative comparison of growth-associated protein-43 and substance P in ulcerative colitis

The aim of this study was to compare immunoreactivities for substance P with other enteric neuropeptides and GAP-43, a general marker for enteric nerves, in normal human colon and in different stages of ulcerative colitis. Tissue samples from normal colon and regions of ulcerative colitis colon were obtained at surgery and immunostained for substance P, vasoactive intestinal polypeptide (VIP), somatostatin, calcitonin gene-related peptide (CGRP), enkephalin, galanin, GAP-43, and neuron-specific enolase (NSE). Visual examination and semiquantitative analysis revealed a clear increase in the immunoreactivity for substance P in ulcerative colitis, whereas no differences were observed in the distribution of the other peptides. Therefore, quantitative analysis was performed only for substance P immunoreactivity in the lamina propria, circular muscle layer, and myenteric ganglia. In the lamina propria, the score of total intensity of substance P immunoreactivity was 0.55 +/- 0.15 (mean +/- SEM) in normal colon, 1.30 +/- 0.35 (p = 0.087) in least affected colon, and 2.22 +/- 0.28 (p < 0.001) in moderately affected colon, whereas no significant differences were observed in immunoreactivities for GAP-43. Similar results were obtained for the mean substance P- or GAP-43-immunoreactive area. In the circular muscle layer, the number, density, total intensity, and perimeter of substance P- and GAP-43-immunoreactive fibers were essentially similar in normal colon, and in mild or moderately affected colon. We conclude that ulcerative colitis does not change the density of gut innervation as a whole. However, the density of substance P-containing nerves is specifically increased, probably due to increased peptide synthesis leading to better visibility of the fibers.

Expression of inducible and endothelial nitric oxide synthases in pouchitis

To study the induction of nitric oxide synthase (NOS) in different forms of pouchitis, we divided patients in five groups: 1) ulcerative colitis, no pouch; 2) no-pouchitis; 3) chronic asymptomatic pouchitis; 4) chronic active pouchitis; and 5) acute pouchitis. Ileal biopsies were scored for NOS-2 (inducible) and NOS-3 (endothelial) immunoreactivity and acute inflammation. In group 1, most specimens lacked NOS-2 immunoreactivity. In group 2, some specimens showed NOS-2 immunoreactive epithelium. In group 3, areas of NOS-2-immunoreactive epithelium were consistently observed in most specimens. In groups 4 and 5, most specimens showed moderate-to-extensive epithelial NOS-2 staining. NOS-2 immunoreactivity scores of groups 1-5 were 0.25 +/- 0.16, 0.67 +/- 0.19, 1.19 +/- 0.40, 2.0 +/- 0.23, and 2.18 +/- 0.12, respectively. Corresponding acute inflammation scores were 0, 0.53 + 0.17, 1.00 +/- 0.33, 1.80 +/- 0.20, and 1.64 +/- 0.15. NOS-2 score correlated with acute inflammation score (p < 0.0001), indicating that NOS-2 induction correlates with both the clinical degree of pouchitis and the severity of acute inflammation. NOS-3 immunoreactivity increased in all pouchitis groups.

Changes in distribution of three isoforms of nitric oxide synthase in ulcerative colitis

BACKGROUND

Nitric oxide (NO) has an important role both in normal physiology and pathological events of the colon. Our aim was to study possible changes of the three nitric oxide synthases in ulcerative colitis (UC).

METHODS

Tissue samples from normal colon and least and moderately affected regions of ulcerative colitis colon were obtained at surgery and immunostained for NOS-1, NOS-2, NOS-3, and GAP-43, a marker of nerve fibers. Quantitative analysis of NOS-1 immunoreactivity was performed on the circular muscle layer.

RESULTS

NOS-1-immunoreactive fibers in the muscularis mucosae disappeared in least affected and moderately affected UC colon. Quantitative analysis of NOS-1-immunoreactive nerve fibers in the circular muscle showed no differences between normal and diseased colon. NOS-2 immunoreactivity appeared apically in the epithelial cells. In normal colon some specimens showed immunoreactivity in lower parts of crypts. NOS-2 immunoreactivity increased according to the severity of UC. NOS-3 immunoreactivity was exclusively localized in the vascular endothelium. The difference in NOS-3 staining intensity between the lamina propria and submucosa observed in normal tissue disappeared in moderately affected UC colon. The number of NOS-3-immunoreactive vascular profiles increased in the lamina propria of UC colon.

CONCLUSIONS

All three NOS isoforms show specific changes in UC colon.

Superior mesenteric and portal vein thrombosis following laparoscopic nissen fundoplication

This case report describes superior mesenteric and portal vein thrombosis after laparoscopic Nissen fundoplication. As a thromboembolic prophylaxis, 2,500 IU of dalteparin was given preoperatively. After postoperative day 19, the patient experienced gradually increasing abdominal pain, mostly related to meals. Physical examination and laboratory tests were normal. CT scan revealed a portal and superior mesenteric vein thrombosis. Dalteparin and warfarin treatment was started, and symptoms relieved rapidly. In a control Doppler ultrasound 1 month after the onset of the treatment, a good flow in the portal and superior mesenteric vein was seen. Possible mechanisms are discussed.

Laminin alpha1-chain shows a restricted distribution in epithelial basement membranes of fetal and adult human tissues

Two novel monoclonal antibodies were raised and used to study the expression of laminin (Ln) alpha1-chain in developing and adult human tissues. In both fetal and adult kidney, a distinct immunoreactivity was seen in basement membranes (BM) of most proximal tubules but not in the distal tubular or glomerular BM or in the basal laminae of blood vessels. Immunoprecipitation of metabolically labeled cultured human renal proximal tubular cells showed an abundant production and deposition of Ln alpha1-chain to the extracellular matrix, suggestive of an epithelial origin of kidney Ln-1. Quantitative cell adhesion experiments with JAR choriocarcinoma cells showed that purified human Ln-1 is a good substrate for cell adhesion that it is differently recognized by integrin receptors when compared to mouse Ln-1. In fetal and adult testes immunoreactivity was solely confined to BM of the seminiferous epithelium. In the airways BM-confined reaction was only seen in fetal budding bronchial tubules (16-19 weeks) at the pseudoglandular stage of development. In the skin a distinct immunoreactivity was confined to BM of developing hair buds but not in epithelial BMs of adult epidermis or of epidermal appendages. In other adult tissues, immunoreactivity was found in BMs of thyroid, salivary, and mammary glands as well as in BMs of endometrium and endocervix, but not of ectocervix or vagina. No immunoreactivity was found in BMs of most of the digestive tract, including the liver and pancreas, except for BMs of esophageal submucosal glands and duodenal Brunner's glands. In fetal specimens, BMs of the bottoms of the intestinal and gastric glands were positive. Basal laminae of blood vessels were generally negative for Ln alpha1 chain with the exception of specimens of both fetal and adult central nervous system in which immunoreactivity for Ln alpha1 chain was prominently confined to capillary walls. The results suggest that outside the central nervous system, Ln alpha1 chain shows a restricted and developmentally regulated expression in BMs of distinct epithelial tissues.

Fatal cardiac tamponade after emergency tension-free repair of a large paraesophageal hernia

Paraesophageal hernia is an unusual disorder of the esophageal hiatus that may be associated with life-threatening mechanical problems. We report a case of a large paraesophageal hernia that presented with acute thoracic herniation and incarceration of the stomach. The patient underwent laparoscopic operation, including reduction of an intrathoracic stomach, hernial sac removal, and tension-free repair of the hiatus with polytetrafluoroethylene (PTFE) mesh. The mesh was fixed with a straight hernia stapler. Postoperatively the patient developed a fatal cardiac tamponade secondary to a coronary vein laceration due to fixation of the mesh with the stapler. Different operative techniques and possibilities for prevention of the complication are discussed.

Basement membrane laminin-5 is deposited in colorectal adenomas and carcinomas and serves as a ligand for alpha3beta1 integrin

Interplay between laminin-5 (Ln-5) and its integrin (Int) receptors alpha2beta1, alpha3beta1 and alpha6beta4 has been implicated in the progression and invasion of carcinomas. In this study we found abundant immunoreactivity for chains of Ln-5 (alpha3-beta3-gamma2) and Ln-10 (alpha5-beta1-gamma1), as well as for type VII collagen, in basement membranes (BM) of colorectal adenomas. In carcinomas of all differentiation grades, Lns were seen in tumor BMs, whereas type VII collagen was almost absent. Ln-5 appeared to accumulate along the invading edges of carcinomas, while Ln-10 was mostly absent. Immunoreactivity for Ln al chain, a component of Lns-1 and -3, was not seen in adenomas or carcinomas. Immunoreactivity for alpha2, alpha6, beta1 and beta4 Ints was found in all tumors and that for alpha3 Int in all adenomas and most of the carcinomas, often in colocalization with Ln-5. Immunoblotting of carcinoma tissues showed that the gamma2 chain of Ln-5 was present as typical Mr 105000 and 155000 isoforms. Immunoprecipitation experiments showed production of Ln-5 by cultured colon carcinoma cells. In quantitative cell adhesion experiments, function-blocking MAbs to alpha3 and beta1 Int subunits, but not those to Int alpha2 or alpha6 subunits, significantly inhibited the adhesion of cells to Ln-5. Our results suggest that BM composition in colorectal adenomas reflects the properties of surface epithelial BM of colorectal mucosa. In invading carcinomas, trimeric Ln-5, produced by carcinoma cells, is a major BM component and the cells use the alpha3beta1 Int complex for adhesion to Ln-5.

Expression of SPARC (secreted protein, acidic and rich in cysteine) in healing intestinal anastomoses and short bowel syndrome in rats

Due to the proposed functions in soft tissue repair, we evaluated the spatial and temporal distribution of SPARC, a counteradhesive, matricellular glycoprotein in healing intestinal anastomoses and short bowel syndrome (SBS) in rats. Intestinal anastomoses were performed in the jejunum of male Wistar rats. SBS was induced by resecting 70% of the small bowel. In situ hybridization was performed to localize SPARC mRNA and immunohistochemical studies for locating the SPARC protein. The granulation tissue in the anastomotic area exhibited immunoreactivity for SPARC at all time points. The level of expression was maximal at seven to nine days. Endothelial cells of capillaries, smooth muscle cells, fibroblastic cells, and macrophages, as well as mesothelial cells on the serosal surface, were stained. The immunoreactivity was mostly intracellular. SPARC mRNA transcripts were localized to the edges of the anastomotic area at days 1 and 4 and on the newly formed granulation tissue later. The expression of SPARC mRNA was maximal at seven days and decreased thereafter. Both in normal controls and in SBS, SPARC was expressed in endothelial cells of submucosal capillaries and in smooth muscle cells but not in epithelium. Based on the restricted temporal and spatial distribution during the healing of intestinal anastomoses and in SBS we propose that SPARC plays a significant role in intestinal repair and adaptation.

Renal cell carcinomas and pancreatic adenocarcinomas produce nidogen in vitro and in vivo

The production of nidogen by four renal cell carcinoma (RCC) and three pancreatic adenocarcinoma (PAc) cell lines has been studied in cell culture and in xenografted tumours in nude mice. In RCC cells, immunoreactivity for nidogen was seen only after exposure to monensin to induce cytoplasmic accumulation of secretory proteins. In PAc cells, immunoreaction was also detectable in control cells. Immunoblotting of control and monensin-exposed cells and immunoprecipitation of culture media of radioactively labelled cells demonstrated the production of nidogen polypeptide of Mr ca. 150000 by six of the seven cell lines. Basement membranes (BMs) and stroma of the xenografted tumours derived from these six cell lines demonstrated immunoreactivity for both human and mouse nidogen, as revealed with species-specific antibodies. The ability of the cells to produce nidogen in vitro and deposit in vivo was positively correlated with high histological grade of the xenografted tumours, although the small number of cell lines studied calls for further studies to confirm this. The distribution of nidogen in human RCC and PAc specimens was also studied by immunohistochemistry. There was strong immunoreactivity for nidogen in tumour stroma, BM of carcinoma cell nests, and endothelial basal lamina, but no conclusions could be drawn regarding histological grade and immunostaining patterns, because stromal production could not be ruled out. The results show that nidogen is produced by human carcinoma cells both in vitro and in vivo.

Laparoscopic Nissen fundoplication: a prospective analysis of 200 consecutive patients

Nissen fundoplication is now the most common antireflux operation for gastroesophageal reflux disease. This study is a report on the laparoscopically performed floppy Nissen procedure. Two hundred consecutive patients were analyzed (84 women, 116 men, mean age 49 years, mean duration of symptoms 5 years) after laparoscopic Nissen fundoplication between 1992 and 1996. The main indications for surgery were daily heartburn, retrosternal pain, and regurgitation demanding continuous medical therapy. Eight patients (4%) had esophageal stricture, and 21 (11%) had Barrett's esophagus with intestinal metaplasia. All patients underwent upper gastrointestinal endoscopy, 24-h esophageal pH monitoring, and esophageal manometry before and 3 months after the operation. In addition, a questionnaire was completed an average of 2.2 years (range 1.0-4.6) after the operation. The results of the study were as follows: mortality was zero, and the morbidity rate was 5%. The mean hospital stay was 3.8 +/- 2.8 days, and sick leave was 14.3 +/- 10.4 days. Postoperatively, esophagitis was healed or significantly improved in all but 4 patients (98%), and 24-h pH and lower esophageal sphincter pressure were normal. After 2 years, 87% of the patients had Visick scores of I-II. It is concluded that laparoscopic floppy Nissen fundoplication provides an efficient and safe alternative for surgical treatment of gastroesophageal reflux disease.

Nerve terminals containing neuropeptides decrease in number after massive proximal small bowel resection in the piglet

The aim of this study was to evaluate possible changes in the neuropeptide innervation pattern of the remaining porcine ileum following 75% proximal resection of the small intestine. Three-month-old piglets were operated on and two months postoperatively full-thickness specimens of the proximal part of the distal ileum wall were taken. Age-matched 3- and 5-month-old unoperated piglets were used as controls. The number and intensity of VIP-, galanin-, enkephalin-, substance P-, and somatostatin-containing nerve fibers were estimated in sections processed for immunofluorescence microscopy and subjected to quantitative scoring. The VIP-, galanin-, and enkephalin-immunoreactive fibers of the circular muscle layer and villi were also quantitated by computer-assisted morphometry. The number and intensity of VIP-immunoreactive fibers in the mucosa and circular muscle layer markedly decreased after resection as compared to 3-month-old and 5-month-old controls (P < 0.05). The galanin immunoreactivity index decreased significantly after resection in the circular muscle layer as compared to both control groups (P < 0.05). The increase in the number of enkephalin-immunoreactive nerve fibers that normally occurred from 3 to 5 months of age was inhibited by the resection. We were not able to see any differences in somatostatin or substance P immunoreactivity between the groups. The results suggest that massive resection induces significant changes in the neuropeptide-containing innervation of the remaining small intestine. These findings are compatible with altered motor activity and mucosa function in the remain intestine.

Cholesterol metabolism and serum and biliary noncholesterol sterols in gallstone patients during simvastatin and ursodeoxycholic acid treatments

Effects of long-term high-dose ursodeoxycholic acid (UDCA) and simvastatin treatments on cholesterol metabolism and biliary lipid compositions were compared in patients with cholesterol gallstones. Absorption and synthesis of cholesterol, serum and biliary noncholesterol sterols and lipids were determined in 14 patients randomized to UDCA (23-25 mg/kg/d) or simvastatin (40 mg/d) for 1 year. Simvastatin reduced serum low-density lipoprotein cholesterol by 55%, and UDCA, by 9%. Cholesterol absorption was decreased (35%) by UDCA, but nonsignificantly increased by simvastatin (P < .05 for difference of changes caused by the two drugs). Whole-body synthesis and biliary output of cholesterol were both significantly decreased only by UDCA. In addition, UDCA inconsistently increased the proportions of serum and biliary precursor sterols of cholesterol, known to reflect cholesterol synthesis, but did not affect their biliary secretions. Simvastatin, however, dramatically reduced serum and also biliary cholesterol precursor sterol proportions and their biliary secretions and increased proportions of serum and biliary plant sterols and cholestanol, known to reflect cholesterol absorption, but had no effect on their biliary secretion. Only UDCA significantly decreased the molar percentage of cholesterol, the lithogenic index, and the cholesterol/phospholipid (CH/ PL) ratio in bile, whereas both treatments inconsistently decreased the vesicular CH/PL ratio (P < .07 in both groups). It is concluded that both drugs decreased serum cholesterol and inhibited cholesterol synthesis, but had a differing influence on precursor sterols and the absorption of cholesterol. UDCA had more beneficial effects than simvastatin on the antilithogenic properties of bile.

Randomised trial of laparoscopic versus open cholecystectomy for acute and gangrenous cholecystitis

BACKGROUND

Laparoscopic cholecystectomy (LC) has become the treatment of choice for elective cholecystectomy, but controversy persists over use of this approach in the treatment of acute cholecystitis. We undertook a randomised comparison of the safety and outcome of LC and open cholecystectomy (OC) in patients with acute cholecystitis.

METHODS

63 of 68 consecutive patients who met criteria for acute cholecystitis were randomly assigned OC (31 patients) or LC (32 patients). The primary endpoints were hospital mortality and morbidity, length of hospital stay, and length of sick leave from work. Analysis was by intention to treat. Suspected bile-duct stones were investigated by preoperative endoscopic retrograde cholangiography (LC group) or intraoperative cholangiography (OC group).

FINDINGS

The two randomised groups were similar in demographic, physical, and clinical characteristics. 48% of the patients in the OC group and 59% in the LC group were older than 60 years. 13 patients in each group had gangrene or empyema, and one in each group had perforation of the gallbladder causing diffuse peritonitis. Five (16%) patients in the LC group required conversion to OC, in most because severe inflammation distorted the anatomy of Calot's triangle. There were no deaths or bile-duct lesions in either group, but the postoperative complication rate was significantly (p=0.0048) higher in the OC than in the LC group: seven (23%) patients had major and six (19%) minor complications after OC, whereas only one (3%) minor complication occurred after LC. The postoperative hospital stay was significantly shorter in the LC than the OC group (median 4 [IQR 2-5] vs 6 [5-8] days; p=0.0063). Mean length of sick leave was shorter in the LC group (13.9 vs 30.1 days; 95% CI for difference 10.9-21.7).

INTERPRETATION

Even though LC for acute and gangrenous cholecystitis is technically demanding, in experienced hands it is safe and effective. It does not increase the mortality rate, and the morbidity rate seems to be even lower than that in OC. However, a moderately high conversion rate must be accepted.

A case report of biliary cystadenoma and cystadenocarcinoma

Three cases of intrahepatic biliary cystadenoma with mesenchymal stroma and one case of biliary cystadenocarcinoma are presented. Their immunohistochemical features and the surgical treatment are discussed together with a brief review of the literature. The benign cystadenomas stained positive for cytokeratin and CA 19-9 in the epithelium of the cyst wall. Mesenchymal stromal cells were strongly positive for a-SMA and moderately positive for desmin. The epithelium of the cystadenocarcinoma, however, was positive only for cytokeratin and the stroma only for a-SMA. Our findings indicate that biliary cystadenomas seem to be of primitive hepatobiliary origin. Furthermore, the malignant variant cystadenocarcinoma may loose its immunoreactivity for CA 19-9 and desmin.

Pancreatic carcinomas deposit laminin-5, preferably adhere to laminin-5, and migrate on the newly deposited basement membrane

We studied the adhesion mechanism of pancreatic carcinoma using in vitro adhesion and migration assays of stable cell lines and tumors grown from these cell lines in nude mice. We also compared the results with the expression profiles of laminins and their receptors in pancreatic carcinomas to evaluate the relevance of these mechanisms in vivo. All of the cell lines preferably adhered to laminin-5, irrespective of their capability to synthesize laminin-5. Cell migration was studied in the presence of hepatocyte growth factor, as it increased the speed of migration manyfold. Herbimycin A treatment and antibodies against the beta 1 and alpha 3 integrin subunits and laminin alpha 3 chain almost entirely blocked cell migration of the BxPC-3 cell line, whereas migration was nearly unaffected by RGD peptide and only moderately inhibited by antibody against the alpha 6 integrin subunit. Indirect immunofluorescence microscopy of wounded BxPC-3 cells suggested a rapid endocytosis of alpha 3 integrin subunit in the cells at the margin of the wound and a rapid, polarized rearrangement of the alpha 6 beta 4 integrin. Especially HGF-treated cultures showed a prominent cytoplasmic reaction for laminin-5 at the margin of the wound. Xenografted cells formed tumors that produced and deposited the same laminin chains as the in vitro cultures. Frozen sections of human pancreatic carcinomas showed reactivity for laminin chains suggestive for expression of laminin-1 and laminin-5. Both xenografted tumors and human pancreatic carcinomas also showed stromal reactivity for laminin-5. Electron microscopy of the human tumors suggested that this was due to an abundant reduplication the basement-membrane-like material around the nests of malignant cells. Our results suggest that pancreatic carcinomas synthesize and deposit laminin-5 in the basement membrane in an abnormal manner. Invading cells adhere to this newly produced basement membrane and migrate on it by using the alpha 3 beta 1 integrin receptor recognizing laminin-5.

Role of Na(+)-H(+)-antiport in restitution of isolated guinea pig gastric epithelium after superficial injury

In addition to its pHi regulatory function Na(+)-H(+)-antiport is also involved in volume regulation of epithelial cells, particularly in neutral conditions. It is also known that the antiport is activated after ligand binding following growth factor receptor activation. The aim of the present study was to evaluate the role of the antiport in restitution of gastric mucosa and whether its activity is dependent on the type of superficial injury. Therefore the fundic epithelium of guinea pig stomach was perfused in an Ussing chamber in neutral conditions. Na(+)-H(+)- and Cl(-)-HCO3(-)-antiports were inhibited with 1.0 mM amiloride, 1.0 mM SITS, or with HCO3- removal and Na(+)-K(+)-2Cl(2-)-cotransporter with 0.3 M furosemide during 4 hr of restitution after superficial injury induced either by 1.25 M NaCl or by 1.0% Triton. Luminal exposure of the epithelium to amiloride had no effect on restitution but serosal application abolished the process completely. The inhibitory effect of amiloride was similar after both NaCl and Triton injury. The inhibition of Cl(-)-HCO3(-)-antiport with SITS interfered with the process as well, while HCO3- removal had no significant inhibitory effect, nor did the inhibition of Na(+)-K(+)-2Cl(-)-cotransporter. The morphologic findings were in accordance with the electrophysiologic measurements in each pair of tissues. It is concluded that the Na(+)-H(+)-antiport is essential for the epithelial cells during restitution even in neutral conditions, but a functional Cl(-)-HCO3(-)-antiport is also required. The activity of Na(+)-H(+)-antiport is sensitive to basolateral amiloride and is necessary regardless of the type of chemical injury.

Alpha 6 beta 4 integrin and newly deposited laminin-1 and laminin-5 form the adhesion mechanism of gastric carcinoma. Continuous expression of laminins but not that of collagen VII is preserved in invasive parts of the carcinomas: implications for acquisition of the invading phenotype

We studied the expression and distribution of different laminin chains, the alpha 6 beta 4 integrin and type VII collagen, i.e., components of the epithelial adhesion complex, in gastric carcinomas and in suggested preneoplastic stages of this malignancy. Intestinal-type gastric carcinomas showed strong reactivity for laminin alpha 1, alpha 3, beta 1, and beta 3 chains, the components of laminin-1 and -5, at the interface between malignant cells and tumor stroma. The reactivities were continuous throughout the carcinomas, even in structures invading through the smooth muscle layers of the gastric wall. The expression of different laminin chains was accompanied by strong polarized reactivity for the alpha 6 beta 4 integrin, which is a receptor for both laminin-1 and laminin-5. Collagen type VII was only occasionally present at sites showing reactivity for laminin-5 and was totally absent from the cell islands invading through the gastric wall. Intestinalized gastric epithelium showed a similar expression pattern of laminins and the alpha 6 beta 4 integrin as the gastric carcinomas. Our results suggest that gastric carcinomas use the alpha 6 beta 4 integrin and newly deposited laminin-1 and -5, accompanied by the disappearance of type VII collagen, as their mechanism of adhesion during the invasion through surrounding tissues. Unlike in previous studies, the reactivity for the laminin-5 protein was not restricted to the invading cells but surrounded the malignant glandular structures throughout the tumor. Our results also show that both intestinal-type gastric carcinoma, and intestinal metaplasia mimic the gastric surface epithelium in the expression pattern of laminins and the beta 4 integrin subunit. This supports previous studies proposing a pathogenetic sequence from intestinal metaplasia to gastric carcinoma.

Substance P--an underlying factor for pouchitis? Prospective study of substance P- and vasoactive intestinal polypeptide-immunoreactive innervation and mast cells

Recent studies suggest that substance P (SP), vasoactive intestinal polypeptide (VIP), and mast cells play a role in inflammatory processes of the bowel. The aim of this study was to evaluate the distribution of SP and VIP immunoreactivities and to count mast cells in the ileal pouch of patients, who had pouchitis after restorative proctocolectomy performed for treatment of ulcerative colitis (UC), and to compare the findings in the same patients after a follow-up period. Nine patients with pouchitis underwent clinical evaluation, endoscopy of the pouch, and histological examination, which were repeated after the follow-up period of 14 months on average. The number and intensity of SP- and VIP-immunoreactive nerve fibers were visualized by immunofluorescence microscopy and subjected to quantitative scoring, and the number of mast cells per unit area was counted. The results were compared to the histological findings and the clinical status. Lamina propria contained fibers showing bright immunofluorescence for SP and VIP. The mean fluorescence intensity score of SP-immunoreactive nerve fibers in the lamina propria remained similar after the follow-up period (2.99 +/- 0.79 and 2.06 +/- 0.82, NS). SP-immunoreactive innervation correlated with the grade of acute (R2 = 0.5396, P = 0.0242) and chronic inflammation (R2 = 0.4561, P = 0.0459), while SP and VIP immunoreactivity, mast cell count, and histological changes did not correlate with the clinical status. The present study demonstrates an increase in the density of SP-immunoreactive nerve fibers in inflamed ileal pouch mucosa of clinically asymptomatic pouchitis patients. These results raise the possibility of therapeutic interference of SP-related processes in treatment of pouchitis.

Substance P- and vasoactive intestinal polypeptide-immunoreactive innervation in normal and inflamed pouches after restorative proctocolectomy for ulcerative colitis

Recent studies suggest that the intestinal polypeptides substance P (SP) and vasoactive intestinal polypeptide (VIP) play a role in the bowel inflammatory processes. The aim of this study was to evaluate the distribution of SP and VIP immunoreactivities in the ileal pouch of the patients with ulcerative colitis (UC). Thirty-six patients underwent clinical evaluation, endoscopy, and histological examinations. Samples were taken from normal ileum (N = 9), ileum of UC patients (N = 9), normal ileal pouch (N = 9) and pouchitis (N = 9). SP- and VIP-containing nerve fibers were visualized in sections processed for immunofluorescence microscopy. The number and intensity of SP and VIP immunoreactivities were subjected to quantitative scoring. On samples from all groups lamina propria contained fibers showing bright immunofluorescence for SP and VIP. The number and intensity of SP immunoreactive nerve fibers were markedly increased in pouchitis as compared to normal pouch (P < 0.005), to ileum of UC patients (P < 0.001), and to normal ileum (P < 0.05). The number and intensity of VIP-immunoreactive nerve fibers in the lamina propria were markedly increased in pouchitis patients and in those having a normal pouch as compared to pooled values of ileum of UC patients and normal ileum (P < 0.05). The results suggest that SP, which may play a role in mediating inflammatory processes, is increased in pouchitis and that VIP, which may contribute to the regulation of intestinal motility, is increased in the pouch.

Laminins, tenascin and type VII collagen in colorectal mucosa

The distribution of different laminin polypeptides, type VII collagen and tenascin has been studied in adult and foetal colorectal mucosa by using the indirect immunofluorescence technique. Immunoreactivity for laminin alpha 1 chain was located to basement membranes of epithelia, muscularis mucosae, and blood vessels, respectively in different segments of adult colon and rectum. Laminin beta 1 and gamma 1 chains were additionally expressed in lamina propria. Laminin alpha 2 chain was also found in lamina propria around the pericryptal fibroblasts. Immunoreactivity for laminin beta 2 chain was restricted to basement membranes in the muscularis mucosae and arteries. Laminin alpha 3 and beta 3 chains, suggestive for laminin-5, were confined especially to surface epithelial basement membranes. Immunoreactivity for type VII collagen was confined to basement membrane of surface epithelium in a punctate manner, while that for tenascin was seen slightly more broadly in the basement membrane zone and also in the muscular layer. The distribution of laminin chains in 16-week-foetal colon mostly resembled that of corresponding adult tissue, although immunoreactivities for laminin alpha 2 and beta 2 chains were lacking. Type VII collagen and the high molecular weight isoform of tenascin were also absent from the foetal colon. The results show that the basement membrane of the surface epithelium of colon and rectum express the components of epithelial adhesion complex, laminin-5 (alpha 3-beta 3-gamma 2) and type VII collagen, resembling in this respect small intestine and stomach while laminin-2 (alpha 2-beta 1-gamma 1) appears to be associated with pericryptal fibroblasts, and laminin-1 (alpha 1-beta 1-gamma 1) widely in most basement membranes.

Milk and egg phospholipids act as protective surfactants against luminal acid in Necturus gastric mucosa

BACKGROUND

Our previous studies indicate that milk phospholipids have anti-ulcer properties in rats and humans, possibly by forming a hydrophobic surfactant layer at the epithelial surface. In the present study we measured intracellular pH and parameters of membrane resistances in gastric epithelium exposed to luminal acid using a microelectrode technique.

METHODS

Chambered isolated Necturus maculosus antral mucosa was exposed to pH 2.3, with or without 20-25 min pre-treatment with milk or egg phospholipids. The pH in surface epithelial cells was measured with double-barrelled liquid sensor pH/PD-microelectrodes.

RESULTS

Pre-treatment with phospholipids (2500-5000 micrograms P/mL) significantly (P < 0.01, n = 14) opposed intracellular acidification. Phospholipids significantly (P < 0.05, n = 14) increased the ratio of apical and basal membrane resistances, suggesting that they primarily affect the apical cell membrane. In contrast, there was no significant change in transmucosal resistance suggesting lack of effect on paracellular shunts in the 'leaky' epithelium.

CONCLUSIONS

Exogenous phospholipids of dietary origin may be used to form a protective layer in the gastric mucosa against irritants.

Changes in substance P-immunoreactive innervation of human colon associated with ulcerative colitis

The amount of colonic substance P and substance P-receptors is increased in ulcerative colitis, which may denote that substance-P is involved as a neurogenic mediator in the inflammatory process of ulcerative colitis. We studied the anatomical distribution of elevated colonic substance P in ulcerative colitis and assessed morphometrically whether the changes in substance P correlate with alterations in colonic innervation. Full-thickness specimens of colonic wall were obtained from normal human colons (N = 9) and the most and least affected regions of ulcerative colitis colons (N = 10) and immunostained for substance P. Substance P immunoreactivity index was calculated by multiplying each intensity value by the number of pixels exhibiting this intensity value. The numbers of substance P-immunoreactive nerve fibers in the lamina propria were markedly increased, and their fluorescence intensity was enhanced in ulcerative colitis. The longitudinal muscle layer contained substance P-immunoreactive nerve fibers in ulcerative colitis, but not in the controls. The substance P-immunoreactive index (= number x intensity of nerve fibers) was 3.42 +/- 1.49 in controls, 21.19 +/- 7.79 in mild ulcerative colitis regions (P < 0.05), and 29.68 +/- 9.81 in severe ulcerative colitis regions (P < 0.01). Increase in the number of substance P nerve fibers is in accordance with the hypothesis that substance P contributes to neurogenic mediation of inflammation in ulcerative colitis.

Differential expression of laminin chains and their integrin receptors in human gastric mucosa

The proliferating cells of the gastric mucosa are found among the pit and mucous neck cells. These cells migrate upward to renew the surface epithelium and downward to restitute the glandular cells. As the epithelial basement membranes (BMs) function as substrate for cell adhesion and migration as well as signals for their differentiation, we studied, by indirect immunofluorescence microscopy, the distribution of different laminin chains and their integrin receptors in adult human stomach. The immunoreactivity for laminin alpha 2 chain localized to the BMs of glands and the lower parts of the gastric pits whereas the laminin alpha 3 chain (laminin-5/kalinin) immunoreactivity was strictly confined to BMs underneath the surface epithelium and the upper parts of the pits. Proliferating mucosal epithelial cells, identified by Ki-67 antibodies, were confined to the areas containing both alpha 2 and alpha 3 laminin chains. The alpha 1, beta 1, and gamma 1 laminin chains were found in all BMs of the mucosa whereas the beta 2 chain was prominent in mucosal blood vessels and also detectable in some glands. Among the laminin integrin receptors, the alpha 3 and beta 4 subunits were seen to be expressed in cells along the BMs with the alpha 3 laminin chain. The alpha 6 integrin, on the other hand, was seen in all gastric epithelia. The present results demonstrate that in the adult human stomach laminin alpha 2 and alpha 3 chains show zonal distribution in BM underlying gastric mucosal epithelium whereas other laminin chains show a more general distribution.

Co-localization of NADPH diaphorase reactivity and vasoactive intestinal polypeptide in human colon

Nitric oxide-containing nervous structures were localized in the human colon using NADPH diaphorase activity and nitric oxide synthase immunoreactivity. We found some, solitary NADPH diaphorase-reactive and nitric oxide synthase-immunoreactive neurons in the submucous plexus, while the myenteric plexus contained several neurons, often arranged in clusters, and nerve fibers showing these markers. The circular muscle layer contained a dense plexus of NADPH diaphorase-reactive nerves, which was greater than that in the longitudinal muscle layer. We report on co-localization of NADPH diaphorase activity and VIP immunoreactivity in several neurons of the myenteric ganglia. Such co-localization has not been reported previously for human colon. Localization of nitric oxide synthase and VIP in the myenteric plexus and in the nerves of circular muscle layer raises the possibility that nitric oxide contributes to the regulation of motility in the human colon.

Catecholamine-synthesizing enzymes in the rat stomach

Local production of catecholamines in the stomach of the rat was studied by immunohistochemical demonstration of tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyltransferase (PNMT), the enzymes catalyzing the formation of dopamine, noradrenaline and adrenaline, respectively. A rich innervation of TH- and DBH-immunoreactive nerve fibers was seen in the muscular layers and the myenteric plexus, in the submucosa and in the walls of submucosal blood vessels and in the lamina propria at the base of the epithelial layer. In addition, TH-, but not DBH-immunoreactive nerve fiber networks surrounding ganglion cells in the myenteric plexus were frequently observed, indicating dopaminergic preganglionic innervation of the myenteric plexus. In the oxyntic epithelium, single TH- and DBH-immunoreactive fibers extended in the strands of lamina propria as far as the middle portion of the gastric glands. A small population of single angulate cells in the oxyntic epithelium showed TH-, but not DBH-immunoreactivity. No specific PNMT immunoreactivity was observed.

Regulation of intracellular pH in isolated Necturus gastric mucosa during short-term exposure to luminal acid

BACKGROUND/AIMS

Continuous exposure to gastric acid implies efficient control mechanisms of intracellular pH (pHi) in the gastric epithelium. This study assessed the roles of Na+, H+, and HCO3- transport mechanisms in controlling pHi during short-term exposure of the gastric epithelium to luminal acid.

METHODS

pHi and Na+ activity (aiNa) were measured with liquid sensor microelectrodes in isolated Necturus antral mucosa, modulating ion transport mechanisms by ion removal and pharmacological inhibition.

RESULTS

Short-term exposure to luminal acid (pH 2.3) acidified pHi by 0.3 pH units, whereafter pHi stabilized. This was associated with transient increase in aiNa. Blocking of Na+/H+ exchange (in the presence of HCO3-/CO2) by removal of Na+ or addition of amiloride eliminated the increase in aiNa and resulted in uncontrolled acidification of pHi. Similarly, blocking of HCO3- transport (in the presence of Na+) by removal of HCO3-/CO2 or addition of 4-acetamido-4-isothiocyanatostilbene-2,2-disulfonic acid resulted in uncontrolled acidification of pHi despite increase in aiNa. Blocking of Na+/K+ exchange with ouabain eliminated the recovery of aiNa and also resulted in uncontrolled acidification of pHi.

CONCLUSIONS

The data indicate that during short-term exposure of the gastric mucosa to luminal acid, both Na+/H+ antiport and HCO3- transport are needed to control pHi and maintain it within physiological ranges.

Recent trends in mortality from peptic ulcer disease in Finland

The enormous change of medical therapy of peptic ulcer disease in the 1970s has resulted in a significant decrease of elective ulcer surgery. It has been speculated whether this might be reflected in the mortality of the disease. Therefore, in the present study, the mortality rate of the disease was evaluated in Finland during the past 17 years covering the dramatic change in the medical therapy: the introduction of H2-receptor antagonists. This was done with a population-based epidemiological study by analyzing 1262 death certificates of people dying from peptic ulcer disease in Finland between 1972 and 1989. The study showed that there has been almost twofold increase in the mortality of the disease between 1972 and 1989 in Finland. This was mainly due to the significantly increased number of fatal ulcer hemorrhages in older people, but also mortality from ulcer perforations increased. This unfavorable epidemiological progress was most striking among elderly women and became manifest during the 1980s. We conclude that mortality from peptic ulcer disease has significantly increased in Finland due to fatal ulcer hemorrhages and perforations. This epidemiological change became manifest in the 1980s, concurrently with the dramatic change in the medical therapy of peptic ulcer disease.

Liver involvement and its course in patients operated on for ulcerative colitis

The prevalence of associated liver involvement in 214 patients with ulcerative colitis undergoing definitive surgery was evaluated, with special emphasis on the subsequent course of liver changes. At the time of colectomy or proctocolectomy 45 patients (21%) had more than transient liver involvement, and 13 (6.1%) fulfilled the criteria of primary sclerosing cholangitis (PSC). Of the other 32 patients with minor liver involvement four had steatosis, one chronic active hepatitis, one viral A hepatitis, and 14 possibly early sclerosing cholangitis or unspecific reactive hepatitis. During a mean follow-up of nine years, four patients with PSC (31%) showed clinical progression, but none of those with minor histological changes or those with no liver disease at surgery did so. Alkaline phosphatase levels showed a decreasing tendency, and minor histological changes improved after surgery, while repeated cholangiography mostly demonstrated progression or a static state. The results indicate that asymptomatic sclerosing cholangitis in association with ulcerative colitis is not always a progressive disease, and proctocolectomy may have a beneficial effect on the long-term course of sclerosing cholangitis in its early phase.

Genomic organization of the human catechol O-methyltransferase gene and its expression from two distinct promoters

Human genomic DNA fragments containing catechol O-methyltransferase (COMT) sequences were isolated and the exon-intron structure analysed by sequencing, PCR and comparing to the human COMT cDNA sequences. The gene contains six exons, of which exons 1 and 2 are noncoding. MB-ATG and S-ATG codons, responsible for the initiation of translation of the membrane-bound (MB) and soluble (S) forms of the enzyme, are located in exon 3. Two distinct COMT-specific transcripts, 1.3 kb and 1.5 kb, were detected in various human tissues and cell lines. Different quantities of the shorter COMT-specific mRNA in the tissues studied suggest a tissue-specific regulation of the COMT gene at transcriptional level. Mapping of the 5' ends of the COMT mRNAs showed that transcription initiates at multiple sites in two separate DNA regions, which are preceded by functional promoter sequences. The proximal promoter (P1), located between the two translation initiation codons and extending approximately 200 bp upstream of the MB-ATG initiation codon, apparently gives rise to the 1.3-kb S-COMT mRNA (S-mRNA). The distal promoter (P2) is located in a DNA fragment in front of and partly overlapping the transcription-start region of the 1.5-kb transcript, suggesting that it controls the expression of this MB-mRNA. Similarities between the rat and human COMT gene promoters are analyzed.

Effect of vagotomy on expression of neuropeptides and histamine in rat oxyntic mucosa

The effect of vagotomy and pyloroplasty on the density of nerve fibers containing bombesin/gastrin-releasing peptide (GRP), calcitonin gene-related peptide (CGRP), and galanin as well as histamine-, 5-hydroxytryptamine (5-HT)-, and somatostatin-containing cells in the oxyntic mucosa of the rat stomach was studied. Ten days after vagotomy and pyloroplasty the density of histamine-containing cells in the oxyntic mucosa was increased by 70% (P < 0.05), and these cells were larger and showed more extensive cell processes than in control animals. The density of 5-HT-immunoreactive (IR) cells and somatostatin-IR cells were not affected. A marked decrease in the density of CGRP-IR nerve fibers and a slighter decrease in the density of GRP-IR nerve fibers was observed in the mucosal layer, while only a minor reduction of CGRP-IR fibers, and no reduction of GRP-IR fibers was seen in the muscular layer. The density of galanin-IR nerve fibers was not affected. The height of the oxyntic mucosa was reduced by about 25% (P < 0.05). Thus, a striking effect on the histamine-IR cells was seen, supporting the view that these cells are regulated by the vagus nerve. The study also indicates that a major portion of the CGRP-IR nerve fibers, and part of the GRP-IR nerve fibers, in the mucosal layer of the fundic region are of vagal origin or regulated by normal vagus nerve activity.

Preepithelial mucus-HCO-3 layer protects against intracellular acidosis in acid-exposed gastric mucosa

The role of the preepithelial mucus-HCO-3 layer in protection against intracellular acidosis was investigated in isolated Necturus gastric antral mucosa exposed to luminal acid by simultaneous measurement of intracellular pH (pH(i)) and extracellular surface pH (pHs) in surface epithelium with microelectrode technique. Acidification of the luminal perfusate to pH 2.5 acidified pH(i) in surface epithelial cells from 7.33 +/- 0.02 to 7.20 +/- 0.04, whereas pHs fell from 6.75 +/- 0.21 to 5.20 +/- 0.25 (P < 0.01; n = 9), followed by a steady state for at least 2 h. Inhibition of epithelial HCO-3 secretion and transport by removal of serosal HCO-3 and CO2 (HEPES and O2 substitution) during acid exposure provoked a progressive acidification of pHs from 5.60 +/- 0.41 to 2.74 +/- 0.14 in 30 min (P < 0.01; n = 9), which was accompanied, after a 5- to 10-min delay, by acidification of pH(i) from 7.21 +/- 0.03 to 5.68 +/- 0.26 (P < 0.01). Digestion of the surface mucus gel by pepsin (5% wt/vol) at pH 2.5 caused a slow acidification of pHs from 5.22 +/- 0.59 to 3.60 +/- 0.46 within 2 h. This was followed by a more rapid acidification to 2.53 +/- 0.38 (P < 0.01; n = 7), with concomitant acidification of pH(i) from 7.19 +/- 0.05 to 6.03 +/- 0.33 (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of interferon alpha on insulin binding and glucose transport in human adipocytes

We have previously demonstrated that interferon administration impairs glucose tolerance and causes insulin resistance in healthy man. Whether this is a direct effect of interferon is not known. The present study was undertaken to examine directly the effect of interferon alpha on insulin binding and action on glucose transport in isolated human adipocytes. Different concentrations of interferon alpha (range 10(-3)-10(5) IU ml-1) and different incubation times (0-5-24 h) with interferon were employed. Acute and 5-h and 24-h exposure of human adipocytes to 10(-2)-10 IU ml-1 of interferon increased the high affinity binding of 125I-insulin (P less than 0.05). In contrast, human interferon alpha had no effect on insulin binding in rat adipocytes. In short-term studies interferon had no effect on 14C-glucose transport clearance. 24-h preincubation of human adipocytes with 10(-2), 10, 10(4) IU ml-1 interferon increased maximally-insulin stimulated 14C-glucose transport clearance (P less than 0.05) and glucose transport responsiveness to insulin was enhanced by 24% (P less than 0.05) in cells exposed to 10(-2) IU ml-1 interferon. After 5 and 24-h preincubations with interferon we observed modest changes in glucose transport sensitivity to moderate concentrations of insulin (50-100 pM) with upregulation in the presence of 10(-2)-10 IU ml-1 interferon and downregulation in the presence of 10(4)-10(5) IUm ml-1 interferon (P less than 0.05). The insulin sensitivity index (ED50) did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular pH in isolated Necturus duodenal mucosa exposed to luminal acid

Regulation of intracellular pH (pHi) and its maintenance within physiological ranges during exposure to luminal acid was studied in isolated Necturus duodenal mucosa using liquid sensor microelectrodes. Exposure of the mucosa to luminal pH 2.7 caused significant intraepithelial acidification. Subsequent removal of HCO3-/CO2 (HEPES/O2 substitution) from the serosal perfusate caused a further decrease of pHi. Blocking of HCO3- transport across the basolateral cell membrane by addition of 4-acetamido-4,isothiosyanostilbene-2,2-disulfonic acid (SITS) to serosal perfusate also caused a slight but significant decrease of pHi. Removal of Na+ (choline substitution) from the serosal perfusate during acid exposure likewise caused a significant decrease in pHi, as did serosal addition of an inhibitor of Na+/H+ antiport, 1 mmol/L amiloride. When Na+ was removed from the serosal perfusate after HCO3- removal, pHi first rapidly acidified; this was followed after an initial 5-minute steady state by an uncontrolled progressive acidification at a rate of 0.33 pH unit/15 min without any further steady state. A similar but weaker effect could also be shown with amiloride addition. The epithelial surface pH was 7.13 +/- 0.08 at the apex of mucosal villus and 7.42 +/- 0.11 (n = 5) in the cryptal area between the villi, i.e., greater than 1 pH unit higher than that of the luminal bulk solution (pH 6), thus suggesting active alkalization of the epithelial surface. Removal of serosal HCO3-/CO2 decreased surface pH significantly both at the villus apex and at the cryptal area, suggesting that the surface alkalization is mediated by transport of serosal HCO3- to the epithelial surface. The data suggest that pHi in acid-exposed duodenal mucosa is primarily maintained within physiological range by an HCO3(-)-dependent mechanism, which, at least in part, exerts its action extracellularly by forming an alkaline buffer layer at the epithelial surface. If adequate serosal (or systemic) HCO3- is not available, a second-line Na(+)-dependent and amiloride-sensitive pHi-regulatory mechanism, presumably an Na+/H+ antiport, becomes the main regulator of pHi.

Different metabolic regulation by adenosine in omental and subcutaneous adipose tissue

Adenosine content was higher in omental adipose tissue (0.91 +/- 0.13 nmol g-1 of wet weight; mean +/- S.E.M.) than in abdominal subcutaneous adipose tissue (0.42 +/- 0.08 nmol g-1 of wet weight) in rapidly frozen surgical biopsy samples taken from ten patients undergoing elective abdominal surgery. This difference was statistically significant (P less than 0.002). The sensitivity of isoprenaline-stimulated lipolysis to inhibition by N6-(phenylisopropyl)adenosine was studied in omental and abdominal subcutaneous adipocytes isolated from nine patients. The effect of this adenosine Ri-site agonist was less pronounced in omental than in abdominal subcutaneous adipocytes which could be due to a desensitization phenomenon. This difference was statistically significant (P = 0.012). The ratio of the inhibitory guanine nucleotide binding proteins Gi1 and Gi2 to the corresponding stimulatory protein Gs was the same in plasma membranes prepared from omental and abdominal subcutaneous adipocytes. In conclusion, in omental adipose tissue, adenosine content is higher and the response to this nucleoside is less pronounced than in subcutaneous adipocytes. This difference cannot be explained by a different (Gi1 + Gi2)/Gs ratio.

Exogenous surface-active phospholipid protects Necturus gastric mucosa against luminal acid and barrier-breaking agents

The nature of the protective action of exogenous surface-active phospholipid on gastric mucosa was studied in isolated Necturus antral mucosa by measuring intracellular pH and intraepithelial potentials and resistances with a microelectrode technique. Exposure of the antral mucosa to luminal pH 2 acidified intracellular pH in surface epithelial cells by 0.6-0.3 pH units. A 20-minute pretreatment with exogenous (pulmonary) surfactanlike phospholipid completely abolished this effect. Obviously, phospholipid protected the mucosa against intracellular acidosis by decreasing the apical cell membrane conductance to H+ (and other ions), because it increased apical cell membrane resistance by +108% and total transcellular resistance by +86% but had no significant effects on paracellular or total transepithelial resistances. In mucosas exposed to three barrier-breaking agents, 10 mmol/L acetylsalicylic acid, 20% (vol/vol) ethanol, and 10 mmol/L taurocholate, at acid luminal perfusate (pH 2.0-2.5), a profound intracellular acidification of 0.9-1.3 pH units/15 min occurred. Pretreatment of the tissue with phospholipid significantly opposed intracellular acidification, but the modulatory influences on the changes in intraepithelial potentials or resistances were less conspicuous and mostly insignificant.

Gastric mucosal acid-base balance

Acute gastric ulceration induced by haemorrhagic shock is associated with profound intramucosal acidification due to diffusion of luminal H+ into the mucosa. High-HCO3- metabolic alkalosis protects the mucosa against this ulceration, whereas low-HCO3- respiratory alkalosis does not, suggesting that lack of systemic and intramucosal HCO3-, rather than tissue acidosis per se, renders the mucosa susceptible to ulceration. In normal mucosa, disruption of the mucosal barrier by taurocholate, ethanol or acetylsalicylic acid leads to efflux of alkali (HCO3-) from the mucosa, with generation of an alkaline buffer layer at the epithelial surface to protect the mucosa from further damage. In ischaemic mucosa no such protective alkaline layer is formed, and exposure to luminal acid leads to severe acidification of and damage to the mucosa. The efflux of alkali may be driven by capillary hydrostatic pressure, since no such protective alkaline efflux occurs in vitro, but rather exposure to luminal acid and barrier-breaking agents results in intracellular acidification. The potential pathogenetic role of a disrupted intramucosal acid-base balance, as well as the protective effect of systemic and intramucosal HCO3- in acute gastric stress ulceration is further substantiated by the in vitro findings that perfusion conditions simulating in vivo ulcerogenic conditions provoke intracellular acidosis, and serosal HCO3- significantly contributes to the maintenance of normal intracellular pH in surface epithelial cells exposed to luminal acid.

Intracellular pH in isolated Necturus antral mucosa exposed to luminal acid

Regulation of intracellular pH in gastric epithelial surface cells exposed to luminal acid was investigated in isolated Necturus antral mucosa using microelectrode technique. Exposure of the mucosa to luminal pH 2 acidified intracellular pH from 7.21 +/- 0.01 to 6.95 +/- 0.04 (N = 50). Removal of Na+ from the perfusates or addition of amiloride (1 mM) to serosal perfusate (containing HCO3-) had no influence on intracellular pH during exposure to pH 2 (N = 6), but removal of HCO3-/CO2 from or addition of 4, acetamido-4-isothiocyanatostilbene-2,2-disulfonic acid (0.5 mM) to the serosal perfusate (containing Na+) acidified intracellular pH from 7.02 +/- 0.03 to 6.45 +/- 0.15 (p less than 0.01, N = 10) and from 6.97 +/- 0.06 to 6.58 +/- 0.26 (p less than 0.01, N = 6), respectively, in 15 min. In tissues exposed to mucosal pH 6, epithelial surface pH was about 1.3 pH units higher than pH of the mucosal bulk solution. Removal of Cl-/HCO3- from the serosal perfusate acidified epithelial surface pH by about 0.5 pH units (p less than 0.01, N = 6), suggesting that serosal HCO3- sustains intracellular pH, at least in part, by generating an alkaline buffer layer at the epithelial surface. In the absence of HCO3-/CO2, a stable intracellular pH was obtained when the tissue was exposed to mucosal pH 2.7, but in this situation intracellular pH was sensitive to Na+ removal or amiloride addition, intracellular pH decreasing from 7.00 +/- 0.07 to 6.48 +/- 0.10 (p less than 0.01, N = 6) and from 6.86 +/- 0.06 to 6.32 +/- 0.01 (p less than 0.01, N = 7), respectively, in 15 min. The data suggest that in gastric epithelium exposed to luminal acid, physiological intracellular pH is primarily maintained by the buffer action of serosal HCO3- transported to the epithelial surface to impede the entry of luminal H+ into mucosal tissue. Removal of the sheltering HCO3- unmasks a second line, Na(+)-dependent and amiloride-sensitive intracellular pH regulatory mechanism, presumably a Na+/H+ antiport.

Acute gastric mucosal lesions, haemodynamic and microcirculatory changes in the thermally injured rat

Early postburn changes in central haemodynamics, organ blood flow distribution and morphology of the gastric mucosa were studied using a standarized thermal skin injury model. Organ blood flow and cardiac output were determined using radioactive microspheres. In the control animals no marked changes in cardiac output or organ blood flow were observed, and the gastric mucosa remained essentially undamaged. After burn injury and no fluid resuscitation, cardiac output decreased by 78 per cent, and blood flow to the stomach, pancreas, spleen, muscle, skin and kidneys also decreased markedly and to about the same degree as the cardiac output, however the adrenal flow remained roughly unchanged at the baseline level. Gross and microscopic lesions developed in the stomach, especially in the corpus. In animals given fluid resuscitation after burn injury cardiac output decreased by 38 per cent during the experiment, but blood flow in the stomach, brain, kidneys and spleen remained fairly constant, while pancreatic and muscle blood flow decreased and adrenal blood flow increased markedly. The gastric mucosa showed only minor microscopic, but no macroscopic lesions at the end of the experiment. The results indicate that acute thermal skin injury induces profound changes in central haemodynamics and organ blood flow which can, however, largely be overcome by adequate fluid resuscitation. The data also suggest that, as in other examples of 'stress ulceration', impaired mucosal blood flow may underlie the stress ulceration which complicates severe burns.