Indocyanine green fluorescence angiography of the reconstructed gastric tube during esophagectomy: efficacy of the 90-second rule

By examining the reconstructed gastric tube during esophagectomy using indocyanine green fluorescence (ICG) angiography, we have established a '90-second rule' to confirm good blood perfusion at the anastomosis site. We examined the surgical outcome (rate of anastomotic leakage) of 70 consecutive patients who underwent esophagectomy with gastric tube reconstruction using ICG fluorescence angiography. All of the anastomoses were made in the area where less than 90 seconds was needed for enhancement using ICG fluorescence angiography (i.e. within the 90-second rule). In 18 cases for which the time until enhancement of the gastric tube tip exceeded 60 seconds, the anastomosis site was decided by reference to the ICG fluorescence angiogram, and the hypoperfused area was excised, and this significantly shortened the median time until enhancement of the gastric tube tip from 95.5 (60.0-204.0) seconds to 41.0 (9.0-77.0) seconds (P < 0.001). In three cases, the anastomosis was made at the site where more than 60 seconds was needed for ICG enhancement. In one case where ICG enhancement had taken 77 seconds, minor anastomotic leakage occurred. The overall rate of anastomotic leakage in this series was 1.4%. Blood flow in the reconstructed gastric tube is sufficient if the anastomosis is made in the area where ICG fluorescence angiography demonstrates enhancement within 60 seconds. Gastric tube necrosis can be avoided if the area showing an enhancement time exceeding 90 seconds is excised. The 90-second rule is a safe and effective method for deciding the site of anastomosis.

Vascular endothelial growth factors C and D and lymphangiogenesis at the early stage of esophageal squamous cell carcinoma progression

We conducted a detailed study of lymphangiogenesis and subsequent lymph node metastasis in early-stage esophageal squamous cell carcinoma (ESCC) using immunostaining for D2-40 and vascular endothelial growth factor (VEGF)-C and D. The study materials included 13 samples of normal squamous epithelium, 6 samples of low-grade intraepithelial neoplasia (LGIN), and 60 samples of superficial ESCC (M1 and M2 cancer 24; M3 or deeper cancer 36). We assessed lymphatic vessel density (LVD) using D2-40 and immunoreactivity for VEGF-C and D in relation to histological type, lymphatic invasion, and lymph node metastasis. LVD in M1 and M2 lesions and M3 or deeper lesions was significantly higher than in normal squamous epithelium (P < 0.001). High expression of VEGF-C and D was observed in M1 and M2 cancer and in M3 or deeper cancer, but not in normal squamous epithelium or LGIN. LVD in VEGF-C- and D-positive cases was significantly higher than in negative cases (P < 0.001). In M3 or deeper cancer, the correlation between VEGF-C or D status and lymphatic invasion or lymph node metastasis was not significant. LVD in cases with positive lymphatic invasion and those with lymph node metastasis was significantly higher than in cases lacking either (P = 0.02 and 0.03, respectively). ESCC cells produce VEGF-C and D from the very early stage of progression. VEGF-C and D activate lymphangiogenesis, and this increase of lymphatic vessels leads to lymphatic invasion and subsequent lymph node metastasis.

Study of termination of postprandial gastric contractions in humans, dogs and Suncus murinus: role of motilin- and ghrelin-induced strong contraction

AIM

Stomach contractions show two types of specific patterns in many species, that is migrating motor contraction (MMC) and postprandial contractions (PPCs), in the fasting and fed states respectively. We found gastric PPCs terminated with migrating strong contractions in humans, dogs and suncus. In this study, we reveal the detailed characteristics and physiological implications of these strong contractions of PPC.

METHODS

Human, suncus and canine gastric contractions were recorded with a motility-monitoring ingestible capsule and a strain-gauge force transducer. The response of motilin and ghrelin and its receptor antagonist on the contractions were studied by using free-moving suncus.

RESULTS

Strong gastric contractions were observed at the end of a PPC in human, dog and suncus models, and we tentatively designated this contraction to be a postprandial giant contraction (PPGC). In the suncus, the PPGC showed the same property as those of a phase III contraction of MMC (PIII-MMC) in the duration, motility index and response to motilin or ghrelin antagonist administration. Ghrelin antagonist administration in the latter half of the PPC (LH-PPC) attenuated gastric contraction prolonged the duration of occurrence of PPGC, as found in PII-MMC.

CONCLUSION

It is thought that the first half of the PPC changed to PII-MMC and then terminated with PIII-MMC, suggesting that PPC consists of a digestive phase (the first half of the PPC) and a discharge phase (LH-PPC) and that LH-PPC is coincident with MMC. In this study, we propose a new approach for the understanding of postprandial contractions.

Increased ghrelin signaling prolongs survival in mouse models of human aging through activation of sirtuin1

Caloric restriction (CR) is known to retard aging and delay functional decline as well as the onset of diseases in most organisms. Ghrelin is secreted from the stomach in response to CR and regulates energy metabolism. We hypothesized that in CR ghrelin has a role in protecting aging-related diseases. We examined the physiological mechanisms underlying the ghrelin system during the aging process in three mouse strains with different genetic and biochemical backgrounds as animal models of accelerated or normal human aging. The elevated plasma ghrelin concentration was observed in both klotho-deficient and senescence-accelerated mouse prone/8 (SAMP8) mice. Ghrelin treatment failed to stimulate appetite and prolong survival in klotho-deficient mice, suggesting the existence of ghrelin resistance in the process of aging. However, ghrelin antagonist hastened death and ghrelin signaling potentiators rikkunshito and atractylodin ameliorated several age-related diseases with decreased microglial activation in the brain and prolonged survival in klotho-deficient, SAMP8 and aged ICR mice. In vitro experiments, the elevated sirtuin1 (SIRT1) activity and protein expression through the cAMP-CREB pathway was observed after ghrelin and ghrelin potentiator treatment in ghrelin receptor 1a-expressing cells and human umbilical vein endothelial cells. Furthermore, rikkunshito increased hypothalamic SIRT1 activity and SIRT1 protein expression of the heart in the all three mouse models of aging. Pericarditis, myocardial calcification and atrophy of myocardial and muscle fiber were improved by treatment with rikkunshito. Ghrelin signaling may represent one of the mechanisms activated by CR, and potentiating ghrelin signaling may be useful to extend health and lifespan.

Endocytoscopic observation of various esophageal lesions at ×600: can nuclear abnormality be recognized?

Endocytoscopy (ECS) is a novel endoscopic technique that allows detailed diagnostic examination of the gastrointestinal tract at the cellular level. We previously reported that use of ECS at ×380 magnification (GIF-Y0002) allowed a pathologist to diagnose esophageal squamous cell carcinoma (ESCC) with high sensitivity (94.9%) but considerably low specificity (46.7%) because this low magnification did not reveal information about nuclear abnormality. In the present study, we used the same magnifying endoscope to observe various esophageal lesions, but employed digital 1.6-fold magnification to achieve an effective magnification of ×600, and evaluated whether this improved the diagnostic accuracy in distinguishing neoplastic from non-neoplastic lesions.We examined the morphology of surface cells using vital staining with toluidine blue and compared the histological features of 40 cases, including 19 case of ESCC and 21 non-neoplastic esophageal lesions (18 cases of esophagitis, 1 case of glycogenic acanthosis, 1 case of leiomyoma, and 1 case of normal squamous epithelium). One endoscopist classified the lesions using the type classification, and we consulted one pathologist for judgment of the ECS images as 'neoplastic', 'borderline', or 'non-neoplastic'. At ×600 magnification, the pathologist confirmed that nuclear abnormality became evident, in addition to the information about nuclear density provided by observation at ×380. The overall sensitivity and specificity with which the endoscopist was able to predict neoplastic lesions using the type classification was 100% (19/19) and 90.5% (19/21), respectively, in comparison with values of 94.7% (18/19 cases) and 76.2% (16/21), respectively, for the pathologist using a magnification of ×600. The pathologist diagnosed two non-neoplastic lesions and one case of ESCC showing an apparent increase of nuclear density with weak nuclear abnormality as 'borderline'. Among the 21 non-cancerous lesions, two cases of esophagitis that were misdiagnosed by the endoscopist were also misinterpreted as 'neoplastic' by the pathologist. We have shown, by consultation with a pathologist, that an ECS magnification of ×600 (on a 19-inch monitor) is adequate for recognition of nuclear abnormality. We consider that it is feasible to diagnose esophageal neoplasms on the basis of ECS images, and that biopsy histology can be omitted if a combination of increased nuclear density and nuclear abnormality is observed.

A novel ligation forceps can be used as a ligature carrier and knot pusher during laparoscopic surgery

BACKGROUND

To extend the usefulness of laparoscopic operations, a secure and easy method for the ligation of large vessels is needed. Herein we describe a novel ligation forceps that can be used as a ligature carrier and knot pusher.

METHODS

A 2-0 suture thread with a knot already tied near one end is hooked in the upper jaw of a novel ligation forceps. After the lower jaw is passed under the vessel or cystic duct, the forceps is closed. When one end of the thread is withdrawn, the knot is trapped in the indentation built into the lower jaw; the ligature is then passed under the pedicle. An extracorporeal ligation can then be performed continuously by the same forceps.

RESULTS

The origins of large vessels were ligated safely and easily with this device during 65 laparoscopic procedures (four total colectomies, 12 colectomies, and 49 gastrectomies). Following temporary hemostasis of accidental bleeding with clamping forceps, ligation hemostasis can also be performed using this instrument.

CONCLUSION

This novel ligation forceps permits the secure ligation of vessels or a cystic duct without the need for another device. The proposed method is both easy and inexpensive.

Effects of denervation at ileocecal junction and ileocecal resection in dogs

BACKGROUND

To investigate neural regulation at the ileocecal junction (ICJ) and motility changes after ileocecal resection (ICR). Previous studies showed normal basal motility at the ICJ directly by force transducers in dogs, but these observations were limited to normal contractile activity.

METHODS

Continuous strain gauge recordings of stomach, terminal ileum, ileocecal sphincter (ICS), and colon were performed in dogs. The dogs were divided into four groups, namely control (CONT), extrinsic denervation at ICJ (ED), intrinsic denervation at ICJ (ID), and ICR groups. Colonic activity was recorded 2 h before a meal, in the early postprandial period (first 2 h), and in the late postprandial period (4-6 h after a meal). The meal lasted 5 min.

KEY RESULTS

Motility index was significantly increased at the ICS (P = 0.0056) and proximal colon (P = 0.0059) after feeding. However, such changes were not observed in the ED and ID groups. The amplitude of contractions at proximal colon in the interdigestive state was significantly decreased by ED. In the ID and ICR groups, the numbers of nonmigrating contractions were significantly decreased (P < 0.05), and colonic migrating motor complex (CMMC) ratio was significantly higher than that of the CONT group (P < 0.001). The dogs in these two groups had diarrhea.

CONCLUSIONS & INFERENCES

Gastrocolonic response at the ICJ may require both intrinsic and extrinsic innervation. When ID was performed, CMMC ratio increased. As a result, intraluminal water absorption may have decreased. ID may be one of the causes of diarrhea after ICR.

Prognostic significance of the expression of MUC1 and collagen type IV in advanced gastric carcinoma

Background

Scirrhous gastric carcinoma is characterized by excessive deposition of collagen in the stroma. However, the clinical significance of this fibrosis of the stomach has not been clarified. The aim of this study was to examine the fibrotic mechanism in several histological types of gastric carcinoma, and the combination of MUC1 and collagen type IV as a possible predictor of patient survival.

Methods

One hundred and two paraffin-embedded specimens of gastric carcinoma were examined by immunohistochemical staining using monoclonal antibodies against collagen type IV and MUC1.

Results

Collagen type IV-positive expression was significantly associated with depth of wall penetration (P = 0·025) and stage (P = 0·023). There was a significant relationship between MUC1-positive expression and interstitial collagen type IV-positive expression (P = 0·035). Survival was shorter for patients with the combination of MUC1-positive expression and interstitial collagen type IV-negative expression than for those with other expression patterns.

Conclusion

In patients with differentiated-type advanced gastric carcinoma, the combination of MUC1-positive and interstitial collagen type IV-negative expression may be a marker of unfavourable prognosis.

Correlation between colonic motility and defecatory disorders after anterior resection of the rectum in canine models

The objective of this study was to describe the correlation between changes in colonic motility and defecatory disorders in four experimental canine models, with an emphasis on denervation. Therefore, we constructed a model by dividing 20 healthy mongrel dogs into four groups, i.e. control, denervation, transection and anterior resection of the rectum (AR) (denervation plus transection), and focused on the correlation between colonic motility and defecatory disorders by counting the colonic migrating motor complexes (CMMCs) and colonic non-migrating motor complexes (CNMCs). Gastrointestinal and colonic contractile activities were continuously recorded on a computer with strain gauge force transducers. The dogs' feces were checked daily, and their consistency was recorded as normal, semisolid, or watery. Compared with the control group, the transection group showed elongation of the propagation time (P < 0.05), and the mean motility index of colonic contractile activity at C4 and C5 in the denervation group was greater than that in the control group (P < 0.05). The AR group showed three features of colonic motility: (i) elongation of the mean CMMC cycle (P < 0.05); (ii) shortening of the propagation time (P < 0.05); and (iii) increment of the number of CNMCs. Concerning fecal consistency, the AR group only showed watery diarrhoea. In conclusion, we revealed the existence of a correlation between defecatory disorders and changes in colonic motility. Increased knowledge among colorectal surgeons of the changes in colonic motility that occur following colorectal surgery is very important and could lead to the curtailment of defecatory disorders among patients.

The peptide hormone xenin induces gallbladder contractions in conscious dogs

Xenin is a 25-amino acid peptide isolated from human gastric mucosa. The biological activities of xenin include modulating intestinal motility and affecting exocrine pancreatic secretion and gastric acid secretion. The physiological effect of xenin on the gastrointestinal tract, however, is incomplete. The objective of this study is to investigate the effects of xenin on the gastrointestinal tract motility of conscious dogs. Gastrointestinal tract and gallbladder contractions were monitored by chronically implanted force transducers. Synthetic xenin was injected intravenously during the interdigestive state with or without pretreatment with cholinergic blockers. The effects of xenin following cholecystectomy and truncal vagotomy were also investigated. Xenin induced gallbladder and jejunal contractions, although a dose-dependent response was shown only with gallbladder contractions. These effects were inhibited by pretreatment with cholinergic blockers, but were not enhanced by truncal vagotomy. The jejunal contractions were completely inhibited by cholecystectomy. The only direct effect of xenin in terms of gastrointestinal motility was to induce gallbladder contractions in conscious dogs. The neural pathway mediating xenin's action was cholinergic, but not the vagal. This novel finding indicates a new role of xenin.

Experimental results and early clinical experience with an easy method for intracorporeal knot tying using a novel laparoscopic needleholder

BACKGROUND

Intracorporeal suturing and knot tying are among the most difficult procedures in laparoscopic operations. An easy and inexpensive method for intracorporeal instrumental ligation with a modified laparoscopic needle driver is presented.

METHODS

The needle driver developed in this study has a novel mechanism that can fix the suturing thread in a hook at the distal site of the holder's jaw hinge. This hook projects out from the rod only when the jaw of the holder is open. After the needle is removed from the tissue using the grasper, the needle driver is placed under the grasper, which the surgeon manipulates by the left hand. Then the thread is hooked on the needle driver by withdrawal of the driver with the jaw opening. The tip of the needle driver is moved over the shaft of the grasper by keeping the thread on the hook. The thread is entwined during a series of crossing movements of the rods of the forceps. The short tail of the suture material is gripped and tied up as a first throw of ligation. The side edge of the jaw, used for thread cutting, is sharpened by grinding.

RESULTS

When the angle of the forceps is set at 90 degrees in the box trainer, no difference in terms of ligation time and degree of error is observed between the hook and conventional C-loop methods. In the case of the 30 degree forceps angle, the novel method is superior to the conventional method.

CONCLUSION

The novel needle driver provides an easy and inexpensive method for performing an intracorporeal ligation, particularly in a case involving a sharp axis angle of the forceps. More clinical experience is necessary for evaluation of this method, but it has potential advantages in laparoscopic operations.

Phase I/II study of S-1 combined with paclitaxel in patients with unresectable and/or recurrent advanced gastric cancer

Both paclitaxel and S-1 are effective against gastric cancer, but the optimal regimen for combined chemotherapy with these drugs remains unclear. This phase I/II study was designed to determine the maximum tolerated dose (MTD), recommended dose (RD), dose-limiting toxicity (DLT), and objective response rate of paclitaxel in combination with S-1. S-1 was administered orally at a fixed dose of 80 mg m-2 day-1 from days 1 to 14 of a 28-day cycle. Paclitaxel was given intravenously on days 1, 8, and 15, starting with a dose of 40 mg m-2 day-1. The dose was increased in a stepwise manner to 70 mg m-2. Treatment was repeated every 4 weeks unless disease progression was confirmed. In the phase I portion, 17 patients were enrolled. The MTD of paclitaxel was estimated to be 70 mg m-2 because 40% of the patients given this dose level (two of five) had DLT. The RD was determined to be 60 mg m-2. In the phase II portion, 24 patients, including five with assessable disease who received the RD in the phase I portion, were evaluated. The median number of treatment courses was six (range: 1-17). The incidence of the worst-grade toxicity in patients given the RD was 28 and 8%, respectively. All toxic effects were manageable. The response rate was 54.1%, and the median survival time was 15.5 months. Our phase I/II trial showed that S-1 combined with paclitaxel is effective and well tolerated in patients with advanced gastric cancer.

Ghrelin does not stimulate gastrointestinal motility and gastric emptying: an experimental study of conscious dogs

Ghrelin is a peptide that was discovered in endocrine cells of the stomach. However, its action in regulating the fasted and fed motor activity of the digestive tract is not fully understood. In the present study, we examined the effects of an intravenous (i.v.) injection of canine ghrelin on the physiological fasted and fed motor activities in the stomach, duodenum, jejunum and colon of freely moving conscious dogs. An i.v. injection of canine ghrelin released growth hormone in a dose-dependent manner; however, it did not stimulate the motor activity of the digestive tract in either the fasted or the fed state. Moreover, an i.v. injection of high-dose canine ghrelin significantly reduced the motility index in the gastric body in the fasted state. Ghrelin did not accelerate gastric emptying, either. These results differ from previous reports dealing with rodents. It is significant that such results were obtained in research with dogs, which are larger animals.

Clinical significance of mucin phenotype, beta-catenin and matrix metalloproteinase 7 in early undifferentiated gastric carcinoma

BACKGROUND

The aim of this study was to examine the clinical significance of mucin phenotypes of early undifferentiated gastric carcinoma, and to identify variables that might be used to select patients suitable for minimally invasive surgery.

METHODS

A total of 129 patients with early undifferentiated gastric carcinoma were studied. The mucin phenotype was determined immunohistochemically using markers for M1, apomucin (MUC) 6 and MUC2. Tumours were classified into gastric (G), intestinal, gastrointestinal (GI) or unclassified type. Undifferentiated carcinomas were classified into signet-ring cell carcinoma (SIG) and non-SIG. The immunoreactivity of matrix metalloproteinase (MMP) 7 and beta-catenin was also investigated.

RESULTS

GI-type tumours more commonly expressed non-SIG than SIG histology. The GI phenotype was associated with a higher incidence of submucosal invasion, lymphatic invasion, MMP-7 expression and nuclear accumulation of beta-catenin than the G type. Non-SIG histology, and the combination of GI type and nuclear accumulation of beta-catenin were independent predictors of submucosal invasion. The combination of GI type and MMP-7 expression independently predicted lymphatic invasion. MMP-7 expression correlated with lymph node metastasis.

CONCLUSION

GI-type early undifferentiated carcinomas and those with non-SIG histology had increased potential for invasion and metastasis. GI type, MMP-7 expression and nuclear accumulation of beta-catenin might prove useful markers in the selection of patients for less invasive surgery.

c-kit Mutation in Generalized Lentigines Associated with Gastrointestinal Stromal Tumor

We describe the case of a 59-year-old Japanese woman presenting with generalized lentigines without systemic anomalies. She had a medical history of gastrointestinal stromal tumors (GISTs), in which gain-of-function mutations of the c-kit gene had recently been found. We detected a point mutation at codon 557 in exon 11 of leukocyte DNA from the patient. The stem cell factor-type III receptor tyrosine kinase pathway plays important roles in the regulation of melanocyte proliferation and differentiation. We speculate that the generalized lentigines of the patient may be caused by melanocyte proliferation due to the c-kit gene mutation.

The technique of laparoscopically assisted total gastrectomy with jejunal interposition for early gastric cancer

BACKGROUND

In recent years, laparoscopic gastrectomy has been applied to the treatment of gastric cancer in Japan. However, there are few reports of laparoscopic or laparoscopically assisted total gastrectomy in the treatment of gastric cancer because of the difficulty of the surgical technique. Laparoscopically assisted total gastrectomies with jejunal interpositions were performed on four patients with early gastric cancer located in the upper portion of the stomach.

METHODS

Four surgical ports were inserted into the abdomen. The stomach was lifted to the abdominal wall using newly developed retraction tubes. Gastric arteries were divided using ultrasonically activated coagulating shears and ligated with ligation forceps. Following these steps, a total gastrectomy reconstruction was performed by jejunal interposition through a small transverse laparotomy. An esophagojejunostomy and a jejunoduodenostomy were made with circular staplers.

RESULTS

The mean operating time and blood loss were 246 min and 236 ml, respectively. The operations were performed without serious complications. All patients were pain free and ambulatory after the laparoscopically assisted total gastrectomy, and the mean postoperative hospital stay was 16 days.

CONCLUSION

We successfully performed laparoscopically assisted total gastrectomies in a relatively short period of time. When patients are carefully selected, the laparoscopic procedure can be curative and minimally invasive as a treatment for early gastric cancer.

Pyloric relaxation regulated via intramural neural pathway of the antrum

Current information about pyloric relaxation is not sufficient. For this reason, our study aimed at measuring pyloric relaxation correctly and determining the role of the intrinsic and extrinsic neural pathway in pyloric relaxation. Five groups of dogs were used: five dogs had an intact gastrointestinal tract (control group); five dogs had transection and reanastomosis of the antrum 3 cm proximal to the pylorus (antral transection group); five dogs had extrinsic pyloric denervation (denervation group); five dogs had transection and reanastomosis of the antrum with extrinsic pyloric ring denervation (transection with denervation group); and five dogs had truncal vagotomy (vagotomy group). Gastropyloroduodenal motility was recorded by a strain-gauge force transducer in conscious dogs. In the control and denervation groups, pyloric relaxation was observed only during phase III of the interdigestive migrating motor complex. In the antral transection, transection with denervation, and vagotomy groups, pyloric relaxation was not observed in either the interdigestive or the postprandial state. The frequency of pyloric contractions increased in these groups in comparison with the control group. In conclusion, the results suggest that pyloric relaxation occurred during phase III to expel undigested particles from the stomach and that descending antral intramural pathways play an important role in the control of pyloric relaxation.

Barostat examination of proximal site of the anastomosis in patients with rectal cancer after low anterior resection

Patients who have undergone low anterior resection (LAR) of the rectum for cancer show symptoms of urgency and frequency of defecation after meals. The cause of these symptoms is unclear. It was hypothesized that the functional disorder of the proximal site of the anastomosis after low anterior resection of the rectum often leads to the symptoms and that the 5-HT3 receptor antagonist reduces postprandial colonic contractions. The aim of this study was to assess colon contractions of the proximal site of the anastomosis and the effects of the 5-HT3 receptor antagonist on the contractions. We evaluated 37 patients who had undergone LARs, 17 with high stool frequency (more than four times per day) and 20 with normal stool frequency. In the first part of the study, basal tone, compliance of the proximal site of the anastomosis, and response to a meal (300 kcal) were recorded with a barostat in all patients. In the second part of the study the effects of the 5-HT3 receptor antagonist on contractions of the proximal site of the anastomosis after ingesting a meal was evaluated. Seven healthy controls were also studied for descending colonic tone with a barostat after a meal. Basal barostat balloon volumes showed only small variations in the two post-LAR groups. Compliance of the proximal site of the anastomosis was similar in the two groups. Meal ingestion stimulated contractions of the proximal site of the anastomosis. In patients with high stool frequency the proximal site of the anastomosis contracted earlier than in those with normal stool frequency after a meal. The descending colonic tone of healthy controls did not change after a meal. The 5-HT3 receptor antagonist inhibited postprandial contractions of the proximal site of the anastomosis after LAR. These observations lend support to the idea that gastrocolonic reflex increases in patients who have undergone LAR, leading to high stool frequency. Furthermore, the 5-HT3 receptor antagonist may alleviate the symptoms of urgency and the frequency of defecation.

Effect of duodenectomy on gastric motility and gastric hormones in dogs

OBJECTIVE

To test the hypothesis that the duodenum is required to coordinate interdigestive insulin secretion with gastrointestinal motility and to determine whether duodenectomy alters the interdigestive cycles of plasma motilin and insulin levels and their relations to insulin secretion and motility.

METHODS

Adult mongrel dogs were chronically implanted with force transducers in the stomach, duodenum, and upper jejunum to monitor contractile activity. Eight healthy mongrel dogs were divided into control and duodenectomized dogs. Insulin secretion, gastrointestinal motility, and plasma concentrations of motilin during the interdigestive period were measured in normal and duodenectomized dogs.

RESULTS

After duodenectomy, no obvious phase III contractions were seen in the gastric antrum, but migrating phase III contractions were seen in the upper jejunum. The plasma motilin concentration did not fluctuate as it does in normal dogs, and remained low. After duodenectomy, insulin secretory cycles were not coordinated with either cycles of interdigestive motility or the plasma concentration of motilin. Exogenous motilin administration stimulated endogenous insulin release significantly compared with saline-treated controls. The contractile response of the stomach to exogenous motilin after duodenectomy was similar to that of intact dogs.

CONCLUSIONS

Duodenectomy disrupts the relation between cycles of both interdigestive gastrointestinal motility and insulin secretion. These effects of duodenectomy may be attributable to interruption of the duodenopancreatic neural connections, hormonal abnormalities, or loss of vagus-sensitive humoral factors. The duodenum, which stores motilin, seems to play an important role in the relations between gastric migrating motor complexes and the concomitant increase of insulin secretion in fasted dogs. The mechanism responsible for the effect of motilin in both duodenectomized and normal dogs may involve a cholinergic pathway.

Circulating soluble Fas ligand in patients with gastric carcinoma

BACKGROUND

The Fas/Fas ligand (FasL) system is involved in cancer cell death induced by the immune system. Most of the tumors may escape the host immune attack by imitating themselves as immune-privileged sites by overexpressing FasL. FasL is synthesized as a membrane-bound protein that can be cleaved to the soluble isoform (sFasL). The objectives of this work were to determine whether the serum concentrations of sFasL in patients with gastric carcinoma were correlated with clinicopathologic features and survival rates.

METHODS

The authors examined the circulating sFasL concentration in 43 healthy people and 166 primary gastric carcinoma patients at the time of diagnosis by enzyme linked immunoadsorbent assay. The results were categorized by clinical and histopathologic variables.

RESULTS

The serum sFasL levels of healthy subjects were all less than 0.1 ng/mL. Among the 166 gastric carcinoma patients, the median concentration of sFasL was 0.04 ng/mL. There were no significant differences between the healthy controls and the gastric carcinoma patients group (P = 0.738). The sFasL levels were significantly increased in patients with gastric carcinoma in a manner reflective of the disease stages such as the depth of tumor invasion, lymph node metastasis, and distant metastasis. The authors determined the cutoff value (0.08 ng/mL) as a 90th percentile of healthy controls. The survival analysis demonstrated that patients with high sFasL levels had a worse prognosis than those with low levels (P < 0.001). Multivariable analysis confirmed that the sFasL concentration was an independent prognostic indicator of overall survival (P = 0.041).

CONCLUSIONS

Our results indicated that sFasL concentrations could not be a new marker for early detection of gastric carcinoma but a prognostic tumor marker for the assessment of the progression of advanced gastric carcinoma.

An easy method for the intraluminal administration of peppermint oil before colonoscopy and its effectiveness in reducing colonic spasm

BACKGROUND

Systemic administration of a cholinergic blocking agent or glucagon is used to reduce spasms, but it is inconvenient and sometimes causes side effects. This study is an evaluation of the intracolonic administration of peppermint oil during colonoscopy for the control of colonic spasm.

METHODS

Each patient in the treated group (n = 409) was given approximately 200 mL of the solution (a mixture of 8 mL of peppermint oil and 0.2 mL of Tween 80 per 1 L of water with 0.04% indigo carmine) by using a hand pump attached to the accessory channel of the colonoscope. Changes in patient posture were made to distribute the solution. The patients in the control group (n = 36) were given the solution without peppermint oil.

RESULTS

A satisfactory spasmolytic effect was seen in 88.5% of the treated patients and in 33.3% of those in the control group (p<0.0001). No adverse effect was observed. The mean time to onset was 21.6 +/- 15.0 seconds, and the effect continued for at least 20 minutes. In patients with irritable bowel syndrome, efficacy was significantly lower (p < 0.0001).

CONCLUSIONS

The intraluminal administration of peppermint oil by using a hand pump is a simple, safe, and convenient alternative to the systemic injection of a cholinergic blocking agent or glucagon during colonoscopy.

Laparoscopically assisted total or distal gastrectomy with lymph node dissection for early gastric cancer

BACKGROUND

A secure lymphadenectomy in a laparoscopically assisted gastrectomy performed for gastric cancer is required because of the high prevalence of lymph node metastasis. A surgical technique for laparoscopic gastrectomy with lymph node dissection and reconstruction using a conventional circular stapler is reported.

METHODS

Forty-nine laparoscopically assisted gastrectomies with lymphadenectomy (47 distal and two total gastrectomies) were performed using devices for retraction of the stomach and laparoscopic ligation of arteries, which were developed to ensure secure dissection of lymph nodes. Reconstruction by Billroth I or intestinal interposition using a conventional circular stapler was performed through a small incision through which the specimen was removed. When submucosal invasion was suspected (n = 16), the lymph nodes along with the common hepatic artery were also dissected through the same incision.

RESULTS

The operations were performed without serious complication. None was converted to laparotomy, and there were no deaths. Metastatic lymph nodes were seen in perigastric nodes and nodes along the left gastric artery in five cases. In five of the 49 patients the macroscopic diagnosis of depth of invasion was underestimated.

CONCLUSION

A technique of laparoscopic gastrectomy with lymph node dissection for early invasive gastric cancer is described. A definitive answer concerning the appropriate level of lymph node dissection and the role of laparoscopic gastrectomy in the treatment of more advanced gastric cancer remains to be defined.

Circulating soluble Fas ligand in patients with gastric carcinoma

BACKGROUND

The Fas/Fas ligand (FasL) system is involved in cancer cell death induced by the immune system. Most of the tumors may escape the host immune attack by imitating themselves as immune-privileged sites by overexpressing FasL. FasL is synthesized as a membrane-bound protein that can be cleaved to the soluble isoform (sFasL). The objectives of this work were to determine whether the serum concentrations of sFasL in patients with gastric carcinoma were correlated with clinicopathologic features and survival rates.

METHODS

The authors examined the circulating sFasL concentration in 43 healthy people and 166 primary gastric carcinoma patients at the time of diagnosis by enzyme linked immunoadsorbent assay. The results were categorized by clinical and histopathologic variables.

RESULTS

The serum sFasL levels of healthy subjects were all less than 0.1 ng/mL. Among the 166 gastric carcinoma patients, the median concentration of sFasL was 0.04 ng/mL. There were no significant differences between the healthy controls and the gastric carcinoma patients group (P = 0.738). The sFasL levels were significantly increased in patients with gastric carcinoma in a manner reflective of the disease stages such as the depth of tumor invasion, lymph node metastasis, and distant metastasis. The authors determined the cutoff value (0.08 ng/mL) as a 90th percentile of healthy controls. The survival analysis demonstrated that patients with high sFasL levels had a worse prognosis than those with low levels (P < 0.001). Multivariable analysis confirmed that the sFasL concentration was an independent prognostic indicator of overall survival (P = 0.041).

CONCLUSIONS

Our results indicated that sFasL concentrations could not be a new marker for early detection of gastric carcinoma but a prognostic tumor marker for the assessment of the progression of advanced gastric carcinoma.

Prostaglandin E2 stimulates motilin release via a cholinergic muscarinic pathway in the dog

Prostaglandins are well known to be widely distributed in mammalian gastrointestinal tissues and to play a role in the regulation of gastrointestinal hormones and contractions. The present study was undertaken to determine whether prostaglandins have an effect on the endogenous release of motilin in the dog. In six conscious dogs, gastrointestinal contractions were monitored by means of chronically implanted force transducers. Prostaglandin E2 (PGE2; 3, 10, 30 microgram kg-1) was given intravenously during the interdigestive phase I period with or without a muscarinic or nicotinic receptor antagonist. Blood samples were collected from 10 min before, to 30 min after, prostaglandin injection. Indomethacin (5 mg kg-1) was given intravenously to investigate the effect of endogenous prostaglandins on motilin release. PGE2 significantly stimulated motilin release but not gastric contractions. Atropine, but not hexamethonium, blocked PGE2-induced motilin release. Motilin release in response to PGE2 was significantly increased by pretreatment with hexamethonium. Indomethacin inhibited the cyclic release of motilin and gastric phase III contractions. We conclude that PGE2 appears to stimulate motilin release via cholinergic muscarinic pathways, and nicotinic receptors modulate this reaction. PGE2 may be involved in part in the regulation of the cyclic release of motilin and the occurrence of gastric phase III.

Expression of Ets-1 angiogenesis-related protein in gastric cancer

The Ets-1 transcription factor plays important roles in invasiveness and angiogenesis. Using automated immunodetection, we investigated Ets-1 expression and tumor microvessel density (MVD) in relation to the clinical significance of gastric cancer. The MVD of Ets-1-positive tumors was higher than that of Ets-1-negative tumors, but the difference was insignificant. The survival rate of patients with high-MVD tumors was significantly poorer than those with low-MVD tumors, and the survival rate of patients with Ets-1-positive tumors was significantly poorer than that of those with negative ones. These results indicate that Ets-1 expression is a useful marker for predicting the outcome for patients with gastric cancer.

Significance of the measurement of serum trypsin in patients surgically treated for gastric cancer

BACKGROUND/AIMS

The influence of standard lymphadenectomy on the occurrence of damage to the pancreas was evaluated in 107 patients with gastric cancer, by analyzing related serum trypsin and amylase levels, pre- and postoperatively.

METHODOLOGY

We divided the patients into two groups: Group A included 59 patients who underwent a standard D1 gastrectomy, according to the classification outlined by the Japanese Research Society for Gastric Cancer. Group B included 48 patients who underwent a D2 gastrectomy.

RESULTS

Group B patients had significantly elevated serum trypsin levels on the 7th and 14th postoperative days (P < 0.01). The percent increase in serum trypsin in Group B patients was also significantly elevated on the 7th and 14th postoperative days (P < 0.01). However, there were no significant difference between the two groups in the percent increase or level of serum amylase.

CONCLUSIONS

These findings indicate that the measurement of serum trypsin may useful to predict the degree of pancreatic micro-damage caused by lymphadenectomy.

Laparoscopic Nissen fundoplication using laparosonic coagulating shears: report of a case

A 64-year-old man was admitted to Gunma University Hospital because of gastroesophageal reflux disease and hiatus hernia. Endoscopic examination showed a linear ulcer and mucosal redness in the lower esophagus. Gastrointestinal contrast study revealed a large esophageal hiatal sliding hernia. Laparoscopic Nissen fundoplication was then performed. Short gastric vessels were divided and lesser omentum was ablated with laparosonic coagulating shears, and the fundus of the stomach was used to construct the wrap around the esophagus. Three hundred and sixty degree fundoplication was undertaken using four sutures to secure the wrap. The patient is well and is currently free from reflux symptoms. Laparoscopic Nissen fundoplication is effective in the control of gastroesophageal reflux in the patient with hiatus hernia. This case report demonstrates that the use of laparosonic coagulating shears is effective for the division of the short gastric vessels.

Epidermoid cyst of an intrapancreatic accessory spleen--a case report

We report an extremely rare case of a splenic epidermoid cyst of the pancreas in a 51-year-old Japanese male with no clinical symptoms. A cystic tumor of the pancreatic tail was detected incidentally by abdominal ultrasonography. The patient was referred to the Gunma University Hospital for further examination of the pancreatic tumor. Upon diagnosis of a benign cystic tumor, a distal pancreatectomy with splenectomy was performed. Microscopically, the multicystic tumor, which was surrounded by the splenic tissue, was located within the pancreatic tissue. The cysts were lined by non-keratinizing squamous epithelium. The diagnosis of an epidermoid cyst occurring in an intrapancreatic accessory spleen was confirmed. To our knowledge, this is the 4th case ever reported in the English literature.

Loss of standard type of CD44 expression in invaded area as a good indicator of lymph-node metastasis in colorectal carcinoma

PURPOSE

Recent advances have made possible the treatment of small invasive colorectal cancer by means of polypectomy or endoscopic mucosal resection. CD44 expression in cancer cells was identified as an indicator of lymph-node metastasis, which could be evaluated in specimens removed by colonoscopy.

METHODS

The correlation between lymph-node metastasis and the expression of standard-type CD44 in cancer cells was examined immunohistologically using the invaded cancer cells of 61 tissue samples of superficially invasive colorectal cancer. We defined the above as invasive cancer restricted within the colorectal wall. Of the 61 samples, 31 had submucosal invasion and 30 had muscular invasion.

RESULTS

Standard-type CD44 expression in the area of invasion in cases with lymph-node metastasis was remarkably down-regulated. In 43 cases with no lymph-node metastasis, 36 (83.7 percent) of patients had CD44 expression in invaded cells, whereas only two of 18 cases (11.1 percent) with lymph-node metastasis had expression of standard-type CD44 in the same area (P < 0.0001). A total of 69.6 percent (16/23) of patients with loss of standard-type CD44 expression in invaded sites were found to have positive metastasis in the lymph nodes. These results suggest that standard-type CD44 in invasive colon cancer cells could suppress metastasis to the regional lymph nodes.

CONCLUSION

In cases of invasive colorectal cancer, the loss of standard-type CD44 expression in the invaded area is a sensitive marker for metastasis to the lymph nodes. Further investigation with larger patient groups is required to clarify the reliability of loss of standard-type CD44 expression as an indicator for additional surgery after endoscopic resection of submucosal invasive colorectal carcinoma.

A novel rapid colorimetric assay of carcinoembryonic antigen levels in the abdominal cavity to detect peritoneal micrometastasis during gastric cancer surgery

We showed that the carcinoembryonic antigen (CEA) level in a peritoneal washing is an indicator of the postoperative survival of gastric cancer patients. On the premise that the polyvinylidine difluoride membrane adsorbs a fixed quantity of protein, this study was designed to produce a rapid, colorimetric, semi-quantitative assay of peritoneal CEA levels by using anti-CEA antibodies. At the time of laparotomy, peritoneal washings were collected from 60 gastric cancer patients, and CEA levels were determined by our assay and by an enzyme immunoassay (EIA) method. The accuracy of our method corresponded with the results of the EIA method. All the cases with high levels of CEA in the peritoneal washings showed positive color changes. Our new assay had no relation to protein concentrations of the samples. The assay makes use of diluted peritoneal washings without adaptation by protein concentration. The measurement can be completed in the operating room within 30 min. As a result, this assay can detect peritoneal microdissemination easily during surgery, and it can be used as an indication of intraoperative chemotherapy against peritoneal micrometastasis.

Postprandial normal saline intake delays gastric emptying of solids in conscious dogs: partial involvement of CCK in its mechanism

Although it is known that a caloric liquid meal given after food intake delays solid gastric emptying, the effect of a noncaloric liquid is not known. The aims of this study were to determine the effect of normal saline given at 3 hr after feeding on gastric antral motor activity and gastric emptying and to evaluate the role of endogenous cholecystokinin in the changes in gastric function induced by postprandial saline intake in conscious dogs. Two cannulas were implanted in each of five mongrel dogs for infusion of phenolsulfonphthalein into the proximal duodenum and for aspiration of luminal samples from the distal duodenum. Gastric contractile and emptying activity were measured by the force transducer method and a freeze-drying method newly developed by our group, respectively. Postprandial pancreaticobiliary secretion was assessed from amylase and bile acid outputs into the duodenum. One hundred grams of freeze-dried dog food was given as a solid meal after mixing it with 100 ml of normal saline. The dogs were given 100 ml of normal saline per os at 3 hr after feeding. In another study, intravenous administration of devazepide, a specific cholecystokinin-A receptor antagonist, at a dose of 0.1 mg/kg/hr was begun 15 min before postprandial saline intake and continued for 1 hr. Gastric antral motility was significantly (P < 0.01) inhibited for 30 min after the dogs had drunk saline at 3 hr after feeding. The mean fractional emptying rate of gastric solids in percentage per 30 min after postprandial saline intake was significantly (P < 0.05) slower than that in the control study without saline intake at 3 hr after feeding. Amylase output into the duodenum after postprandial saline intake showed a gradual increase lasting for about 1 hr, whereas that of bile acid increased transiently but markedly 15 min after saline intake, in comparison with the control study. Pretreatment with devazepide partially ameliorated the suppression of gastric antral motility. Postprandial intake of saline inhibited gastric motor activity and delayed solid gastric emptying, whereas it increased the outputs of amylase and bile acid. Endogenous cholecystokinin may be partially involved in these phenomena caused by saline intake at 3 hr after feeding.

Effect of EM574 on postprandial pancreaticobiliary secretion, gastric motor activity, and emptying in conscious dogs

EM574, an erythromycin derivative and a potent motilin receptor agonist, is now under clinical trial as a gastroprokinetic drug. The aim of this study was to estimate the effect of EM574 on postprandial pancreaticobiliary secretion, gastric motor activity, and emptying in conscious dogs. Five mongrel dogs were prepared. Indwelling cannulas for both infusion of phenolsulfonphthalein and aspiration of luminal samples were inserted into the proximal and distal duodenum, respectively. EM574 (3-30 microg/kg) was given intraduodenally through the indwelling distal duodenal cannula at the start of feeding. Postprandial pancreatic and biliary secretions were assessed by measuring the outputs of amylase and bile acid into the duodenum, respectively. Gastric motor and emptying activity were measured by means of a force transducer method and our own freeze-drying method, respectively. One hundred grams of a freeze-dried standard meal was given as a solid marker after being mixed with 100 ml of normal saline containing 15 g of polyethylene glycol as a liquid marker. EM574 at doses of 10 and 30 microg/kg significantly increased the mean integrated postprandial amylase output into the duodenum, but the mean integrated postprandial bile acid output was not significantly increased. EM574 increased postprandial gastric antral motor activity dose-dependently. EM574 at doses of 10 and 30 microg/kg significantly accelerated gastric emptying of liquids and solids, respectively. EM574 enhances gastric antral motor activity and accelerates gastric emptying of solids and liquids with a concomitant increase in postprandial pancreatic amylase, but not bile acid, output in normal dogs.

Mechanism of inhibitory effect of glucagon on gastrointestinal motility and cause of side effects of glucagon

Glucagon is commonly used during gastrointestinal examinations for the temporary inhibition of gastroduodenal movements. Three preparations of glucagon are now clinically available: those prepared by extraction from the pancreas (GL-P), by chemical synthesis (GL-S), and by genetic recombination (GL-G). The aim of this study was examine the mechanism of the inhibitory effect of glucagon on gastrointestinal motility and the cause of its side effects by comparing three glucagon preparations. In four conscious dogs, gastrointestinal contractions were monitored by means of chronically implanted force transducers. Each glucagon preparation (GL-P [15 microg/kg], GL-S [5, 15, 45 microg/kg], GL-G [15 microg/kg]), scopolamine butylbromide (0.4 mg/ kg), or saline was administered intravenously 20 min after the termination of spontaneous phase III contractions, and blood samples were taken at 5- to 10-min intervals. Barium was administered into the stomach 10 min after the infusion of each drug. The arrival of a barium meal in the stomach immediately stimulated gastrointestinal contractions, and the barium meal was expelled into the duodenum and jejunum from the stomach. Intravenous injection of 15 microg GL-S first stimulated duodenal contractions that propagated to the jejunum, followed by strong inhibition of the barium-induced gastrointestinal contractions. This inhibitory effect of glucagon and the activity of the glucagon-induced duodenal contractions were dose-related. The inhibitory effects of GL-G and GL-S were stronger than that of GL-P. Blood glucose and plasma insulin concentrations were raised after intravenous injection of each glucagon preparation, but there was no difference among the three preparations and no dose relationship. The inhibitory effects of glucagon depend on the material purity and dose, and the inhibitory mechanism was independent of any effect on carbohydrate metabolism. Glucagon administration caused phase III-like contractions in the duodenum and jejunum, which may be responsible for the side effects of glucagon.

Effects of EM574 and cisapride on gastric contractile and emptying activity in normal and drug-induced gastroparesis in dogs

EM574, an erythromycin derivative and potent motilin receptor agonist, is now undergoing clinical trials as a gastroprokinetic drug. The aim of this study was to compare the effect of EM574 with that of cisapride on gastric motility and emptying in normal and gastroparesis dogs. Six dogs were each implanted with two duodenal cannulas for infusion of phenolsulfonphthalein into the proximal duodenum and for aspiration of luminal samples from the distal duodenum. Both solid and liquid gastric emptying were determined by a novel freeze-drying method developed in our laboratory. A freeze-dried standard meal (100 g, 400 kcal) was given with 100 ml normal saline containing 15 g of polyethylene glycol as a liquid marker. Gastric muscle contractility was measured by means of a force transducer implanted on the gastric antrum. EM574 (3-30 microgram/kg) and cisapride (0.3-3.0 mg/kg) were administered intraduodenally at the start of feeding. Clonidine (3-30 microgram/kg) was injected subcutaneously 15 min before feeding to induce gastroparesis. EM574 and cisapride both enhanced gastric muscle contractility in a dose-dependent manner. EM574 (30 microgram/kg and 10 microgram/kg) significantly accelerated gastric emptying of solids and liquids, respectively. Cisapride (1 mg/kg) significantly accelerated solid gastric emptying, but 3.0 mg/kg significantly delayed liquid gastric emptying. Clonidine (10 and 30 microgram/kg) significantly delayed solid and liquid gastric emptying and reduced gastric muscle contractility. EM574, at a dose of 30 microgram/kg, completely restored solid and liquid gastric emptying and muscle contractility to the normal range in dogs with clonidine-induced gastroparesis. Cisapride (1 mg/kg) restored liquid gastric emptying in dogs with gastroparesis to the normal range and partially restored solid emptying. EM574 accelerated gastric muscle contractility and emptying of solids and liquids in normal dogs. The stimulating activity of EM574 on gastric muscle contractility and emptying was comparable to that of cisapride, but EM574 was as effective as cisapride in normalizing gastric muscle contractility and emptying in dogs with clonidine-induced gastroparesis.

Effect of TKS159, a novel 5-hydroxytryptamine4 agonist, on gastric contractile activity in conscious dogs

A novel 5-hydroxytryptamine (5-HT)4 receptor agonist, TKS159, ¿4-amino-5-chloro-2-methoxy-N-[(2S,4S)-1-ethyl-2- hydroxymethyl-4-pyrrolidinyl] benzamide), has recently been developed as a gastroprokinetic drug. Cisapride is already used clinically to increase gastric contractions. The stimulatory effects of TKS159 and cisapride on gastric contractions were examined using force transducers chronically implanted on the vagally denervated pouch (Heidenhain pouch) and the vagally innervated main stomach in conscious dogs. Contractile activity was analysed by computer and expressed as a motor index. Intravenous administration of TKS159 or cisapride significantly increased the motor index in both the main stomach and the Heidenhain pouch during the fed and fasted states. Pharmacological characterization in the fasted state revealed that the contraction-stimulating activity of TKS159 and cisapride on the stomach was significantly inhibited by atropine, hexamethonium and a 5-HT4 receptor antagonist, SDZ 205-557. Granisetron (a 5-HT3 receptor antagonist) significantly inhibited cisapride-induced, but not TKS159-induced gastric contractions. The plasma motilin concentration was significantly increased after cisapride, but not after TKS159 injection. In conclusion, TKS159 has a contractile-stimulating effect on both the innervated and the denervated stomach. It is likely that a cholinergic pathway and 5-HT4 receptors are involved in producing the contractions, although other mechanisms cannot be excluded. Cisapride has almost the same characteristics, but the present findings suggest the involvement of motilin and 5-HT3 receptors in the effects of cisapride.

An evaluation of motor function in transverse colon transplants after total gastrectomy

The motor activity of the isolated colon is understood less than that of any other part of the gastrointestinal viscus. Thus, the aim of the present study was to evaluate the motor activity of the interposed transverse colon following total gastrectomy through a study of 21 patients. Manometric studies were carried out with a 5-lumen, open-tipped catheter in the resting state, in response to dry swallows, and swallowing distilled water and a liquid meal. Contractile waves in the interposed colon grafts were divided into three types, namely, high-amplitude propagated contractions (HAPCs), low-amplitude propagated contractions (LAPCs), and low-amplitude nonpropagated contractions (LANPCs). No retrograde contractions were observed during the entire recording. Motor activity in the interposed colon increased to a greater extent after swallowing distilled water or liquid meals than during the resting period or after dry swallows; however, there was no significant difference between the effect of distilled water and liquid meals. The motor activity of the interposed colon was lower in patients with symptoms than in asymptomatic patients. These results suggest that the volume, rather than the composition, of the lumen contents is an important factor for inducing interposed colon graft contractions, and that contractions of the interposed colon can help to propel the contents of the colon into the duodenum and clear any duodenal juice if reflux should occur.

Motilin controls cyclic release of insulin through vagal cholinergic muscarinic pathways in fasted dogs

The effect of motilin on insulin release has not been studied in the interdigestive state. Adult mongrel dogs were chronically implanted with force transducers in the stomach and duodenum to monitor contractile activity, and the plasma motilin and insulin concentrations were measured by a specific radioimmunoassay and enzyme immunoassay, respectively. The concentration of insulin in plasma was found to fluctuate in close association with that of motilin and phase III of the interdigestive migrating contractions in the stomach. This spontaneous release of insulin was mimicked by intravenous infusion of motilin at a dose of 0.3 microgram.kg-1.h-1. Exogenous motilin (0.01-0.3 microgram/kg) dose dependently stimulated insulin release, which was abolished by atropine, hexamethonium, ondansetron, and truncal vagotomy. Phentolamine significantly enhanced, whereas propranolol inhibited, motilin-induced insulin release. In a perifusion system using islet cells from the canine pancreas, motilin did not affect insulin release. In conclusion, motilin stimulates insulin release through vagal cholinergic, muscarinic receptors on pancreatic beta-cells, and the effect appears to be modulated by adrenergic nerves.

Neuronal control of motility changes in the canine lower esophageal sphincter and stomach in response to meal ingestion

BACKGROUND & AIMS

Neuronal control of motility changes in the lower esophageal sphincter (LES), gastric body (GB) and gastric antrum (GA) in response to meal ingestion is not fully understood. The aim of this study was to investigate the neuronal mechanism of the LES and gastric motility response to meal ingestion in conscious dogs.

METHODS

Dogs fitted with force transducers in the LES, GB and GA were given neuronal antagonists before a meal. Motility was assessed for 10 min after feeding and was compared to results without antagonists.

RESULTS

In the LES, atropine inhibited tonic contractions, whereas N omega-nitro-L-arginine (L-NAME) significantly enhanced tonic contractions initiated by meal ingestion. In the GB, atropine, hexamethonium or L-NAME inhibited receptive relaxation, and the effect of hexamethonium was significantly greater than that of atropine or L-NAME. In the GA, atropine, hexamethonium or naloxone inhibited postprandial phasic contractions, whereas L-NAME tended to enhance phasic contractions.

CONCLUSIONS

Neuronal control of postprandial motility was clearly different in each region: (1) LES tonic contractions are mainly regulated by muscarinic receptors, (2) nicotinic transmission plays an essential role in receptive relaxation, which also involves muscarinic receptors and nitric oxide, (3) cholinergic nerves and opiate receptors are involved in the occurrence of antral phasic contractions, and (4) endogenous nitric oxide may inhibit postprandial contractions in the LES and GA.

Motilin is a biosignal controlling cyclic release of pancreatic polypeptide via the vagus in fasted dogs

The mechanism of associated fluctuations in plasma motilin and pancreatic polypeptide (PP) concentrations was studied in fasted conscious dogs while gastric motility was monitored. Plasma motilin and PP concentrations were measured by radioimmunoassay. In intact normal dogs, exogenous motilin (0.03-0.3 g/kg) stimulated dose-related release of PP, but PP did not stimulate motilin release. Motilin-induced PP release was completely inhibited by pretreatment with cholinergic blockers and a 5-hydroxytryptamine3 (5-HT3) receptor antagonist, and by vagotomy. The cyclic release of PP was abolished after vagotomy and duodenectomy. However, PP release stimulated by exogenous motilin was apparent after duodenectomy but not after vagotomy. In conclusion, motilin appears to stimulate PP release via vagal, cholinergic muscarinic pathways involving 5-HT3 receptors and to act as a biosignal controlling PP release by mediating the interdigestive periodic changes in the duodenum to the center of the autonomic nervous system. This represents a new role for motilin.

Exogenous motilin stimulates endogenous release of motilin through cholinergic muscarinic pathways in the dog

BACKGROUND & AIMS

Exogenous motilin is believed to stimulate endogenous release of motilin, but this has not been studied in detail. The aim of this study was to investigate whether and by what mechanism exogenous motilin stimulates endogenous release of motilin in the dog.

METHODS

Gastric and duodenal contractile activity in conscious dogs was monitored by chronically implanted force transducers. Plasma canine motilin (c-motilin) concentrations in response to exogenous porcine motilin (p-motilin) were determined by specific radioimmunoassay for c-motilin. The release of motilin from motilin cells obtained from canine duodenal mucosa was studied in vitro using a perifusion system.

RESULTS

In vitro, c-motilin release was stimulated by carbachol but not by p-motilin, and the carbachol-induced c-motilin release was inhibited by atropine. In vivo, exogenous p-motilin stimulated endogenous c-motilin release and gastric and duodenal phase III-like contractions; this motilin-induced motilin release was inhibited by atropine, hexamethonium, and a 5-hydroxy-tryptamine 3 receptor antagonist.

CONCLUSIONS

In the dog, exogenous motilin stimulates endogenous motilin release through muscarinic receptors on motilin-producing cells via preganglionic pathways involving 5-hydroxytryptamine 3 receptors.

Role of endogenous 5-hydroxytryptamine in the regulation of gastric contractions by motilin in dogs

It has been suggested that 5-hydroxytryptamine3 (5-HT3) receptors are involved in the control of phase III contractions in the stomach. We examined the effect of depletion of endogenous 5-HT by p-chlorophenylalanine (pCPA) on spontaneously and motilin-induced phase III contractions in conscious dogs, and the effect of 5,6-dihydroxytryptamine (5,6-DHT) in an isolated perfused dog stomach. Three-day treatment with pCPA significantly reduced plasma 5-HT concentration and 5-HT content in the stomach, and strongly suppressed the spontaneous and motilin-induced phase III contractions in the stomach. When spontaneous phase III contractions recovered in the stomach after a 3-day treatment, exogenous motilin induced typical phase III-like contractions, and the 5-HT content in the muscle layer was recovered to the normal pretreatment level. In the perfused stomach, 5,6-DHT decreased 5-HT content in the muscle layer alone and abolished motilin-induced contractions. In conclusion, endogenous 5-HT, probably in 5-HT neurons, plays an important role in the control of interdigestive phase III activity by motilin in the stomach.