Toshihiro Nakabayashi

Gastrointestinal recovery and outcome after laparoscopy-assisted versus conventional open distal gastrectomy for early gastric cancer

AbstractLaparoscopy-assisted gastrectomy has been increasingly reported as the treatment of choice for early gastric cancer. However, there is little information regarding the benefits of laparoscopy-assisted distal gastrectomy (LADG). LADG and conventional open distal gastrectomy (DG) for early gastric cancer were compared in terms of operative outcome, recovery of bowel function, complications, and changes in body weight. Thirty-four patients underwent LADG for early gastric cancer. These patients were compared with 31 patients who underwent DG during the same period. For estimating gastrointestinal motility recovery, 20 radiopaque markers were inserted into the duodenum during surgery, and abdominal X-rays were taken daily until all markers were seen in the ascending colon. Age, gender, and histologic differentiation of the lesions were matched. The LADG group required a significantly longer operative time and the dissection of fewer lymph nodes. Postoperative hospital stay and the occurrence of postoperative complications (ileus) were significantly shorter and less frequent in the LADG group. The LADG group showed a more rapid recovery of gastrointestinal motor function compared with the DG group during the early postoperative period. Body weight 24 months after LADG was about 100% of pre-illness weight, but no further weight change was encountered in the DG group. For selected patients with early gastric cancer, LADG with lymphadenectomy can provide a rapid recovery and good quality of life without compromising the cure rate.

18F-Fluorodeoxyglucose Positron Emission Tomography: Useful Technique for Predicting Malignant Potential of Gastrointestinal Stromal Tumors

The malignant potential of gastrointestinal stromal tumors (GISTs) is difficult to diagnose before surgery because the diagnoses are based on tumor diameter and mitotic index. The progression of small GISTs is always observed because they do not seem to have malignant potential. 18F-Fluorodeoxyglucose (FDG)-positron emission tomography (PET) is a useful technique for assessing tumor activity. The objective of this study was to determine if FDG-PET is useful for predicting the malignant potential of gastric GISTs. Ten patients diagnosed with gastric GISTs participated. FDG-PET was performed on all of them before tumor resection. A whole-body image was initiated 40 minutes after the injection of 275 to 370 MBq FDG. FDG uptake was assessed by a standardized uptake value. All tumors had FDG uptake. There was a significant correlation between the FDG uptake and both the Ki67 index and the mitotic index but not the tumor diameter. The FDG uptake and malignant potential of gastric GISTs had a significant correlation. FDG-PET may be of considerable value for predicting the malignant potential of gastric GISTs before surgery. A gastric GIST with a high FDG uptake should be regarded as having malignant potential.

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

Abstract  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.

Laparoscopy-assisted gastrectomy for early gastric cancer in young and elderly patients.

Open gastric surgery in elderly patients is associated with higher morbidity and mortality rates than those reported among younger individuals. Therefore, minimally invasive surgery may have a larger impact on the elderly compared to the younger age group. The objective of this study was to evaluate the experience of laparoscopy-assisted distal gastrectomy (LADG) in patients with early gastric cancer and compare the results in patients 70 years of age and older to those in patients younger than 70 years of age. From January 1998 to October 2004, a total of 103 patients underwent LADG. Of these patients, 30 who were older than 70 years were compared with 73 who were younger. Preoperative co-morbidity, operative results, postoperative outcomes, and survival were analyzed. Furthermore, as a standard control of this study, we reviewed 54 distal gastrectomy cases with open surgery (open distal gastrectomy; ODG) in the same term with the same background factors, categorized into elder (n = 16) and younger (n = 38). The mean age of the elderly patients was 75 years in the LADG group. A significantly higher proportion of elderly patients had concurrent diseases in both groups. Blood loss was significantly less in the elderly than in younger patients undergoing LADG, and it was less in the LADG group than in the ODG group. The overall 5-year survival rates in the LADG group were not significantly different between elderly and younger patients. Laparoscopy-assisted distal gastrectomy is a safe and effective treatment for early gastric cancer in the elderly. Therefore, chronological age alone should not be considered a contraindication in selecting patients for LADG.

Gastropyloric motor activity and the effects of erythromycin given orally after esophagectomy

BACKGROUND The motor activity of the gastric tube as an esophageal replacement after esophagectomy is poorly understood. The aims of the present study were to examine the gastropyloric motility of the gastric tube and the effects of erythromycin given orally. METHODS Interdigestive gastropyloric motility was recorded by manometry with a sleeve sensor in 23 esophagectomized patients. The 23 patients were classified into 3-, 12-, and 24-month groups according to postoperative follow-up time. Radiopaque markers were used in 8 patients to assess gastric emptying. The effects of erythromycin were studied after the patients received 600 mg during fasting and 1 g postprandially. RESULTS Compared with the 3-month group, the 12-month group and the 24-month group showed significantly increased pyloric and antral motility, respectively. During a fast, erythromycin induced phase III in 44.4% of the patients with more than 12 months of follow-up. In contrast to the normal subjects, esophagectomized patients showed delayed gastric emptying at 3 and 4 hours. However, erythromycin significantly accelerated gastric emptying at 1, 2, 3, and 4 hours. CONCLUSIONS The motor activity of the gastric tube returns towards normal in a progression over time from the pylorus cephalad. Erythromycin given orally might be used as a prokinetic agent in patients after esophagectomy.

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

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.

Pyloric motility after pylorus-preserving gastrectomy with or without the pyloric branch of the vagus nerve.

An attempt was made to examine gastropyloric motility after pylorus-preserving gastrectomy (PPG) and to determine the influence of the pyloric branch of the vagus nerve in the dog. Fifteen dogs were divided into three groups of five. PPG with preservation (PPPG) and resection of the pyloric branch of the vagus (RPPG) were performed, and controls were prepared. Interdigestive and digestive gastropyloroduodenal motility was recorded after a 2-week recovery period using strain-gauge force transducers (SG). Radiopaque markers (ROMs) were used to assess gastric emptying. No significant differences were found between PPPG and RPPG in terms of gastropyloroduodenal motility during either the interdigestive or the postprandial state. During phase III of the interdigestive state, pyloric relaxation correlated with contraction of the gastric body after both PPPG and RPPG. During the first month it was accompanied by tonic and phasic pyloric contractions after feeding and delayed gastric emptying in two groups. By the end of the first month these pyloric contractions had diminished, and the rate of gastric emptying was similar to that of the controls. We concluded that it is not necessary to preserve the pyloric branch of the vagus for gastropyloroduodenal motility after PPG. Gastric stasis during the early postoperative period is due to tonic and phasic contractions of the pylorus.RésuméOn a examiné la motilité gastropylorique après gastrectomie avec conservation du pylore (GCP) et notamment, le rôle de la branche pylorique du nerf vague chez le chien. Quinze chiens ont été divisés en trois groupes de cinq, un groupe de contrôle, un deuxième groupe de GCP et un troisième avec résection de la branche pylorique du nerf vague (RBPV). On a enregistré la motilité gastropyloroduodénale interdigestive et digestive après une période de deux semaines à l’aide de transducteurs «strain gauge force» (SGF). Des marqueurs radio-opaques ont été utilisés pour évaluer la vidange gastrique. On n’a observé aucune différence statistiquement significative entre les groupes GCP et RBPV en ce qui concerne la motilité gastropyloroduodénale pendant la période interdigestive ou postprandiale. Pendant la phase III de l’état interdigestif, la relaxation pylorique était couplée à une contraction du corps gastrique après la GCP et la RBPV. Pendant le premier mois, elle était accompagnée de contractions pyloriques toniques et phasiques après l’alimentation et un retard de la vidange gastrique dans les deux groupes. Cependant, après un mois, ces contractions avaient diminué et la prévalence de vidange retardée était similaire aux contrôles. En conclusion, il ne semble pas nécessaire de conserver la branche pylorique du vague pour la motilité gastropyloroduodénale après GCP. La stase gastrique postopératoire précoce est en rapport avec des contractions toniques et phasiques du pylore.ResumenSe realiza un estudio experimental en perros para dilucidar la acción de la rama pilórica del n. Vago en la motilidad gastro-pilórica, tras una gastrectomía con preservación del píloro (PPG). Se utilizaron 15 perros divididos en 3 grupos de cinco. El grupo control, el grupo PPG, con preservación de la rama pilórica del vago (PPPG), y el grupo con resección de dicho nervio (RPPG). Se registró, transcurridas dos semanas de la operación, la motilidad gastropilórica-duodenal interdigestiva y digestiva, utilizando un transductor que mide la fuerza de necesaria para modificar el calibre (SG). Para evaluar el vaciamiento gástrico se emplearon marcadores radiopacos (ROMs). No se registró diferencia alguna entre los grupos PPPG y RPPG, por lo que se refiere a la motilidad gastropilórica-duodenal tanto interdigestiva como postprandial. En la fase III del estadio interdigestivo, la relajación del píloro se asociaba a una contracción del cuerpo gástrico tanto en el grupo PPPG como en el RPPG. Durante el primer mes (tras la operación) se constataron tras la ingesta, tanto en un grupo como en el otro, contracciones tónicas y fásicas del píloro, con retraso en el vaciamiento gástrico. Sin embargo, al finalizar el primer mes, las contracciones pilóricas disminuyeron y el vaciamiento gástrico fue similar al observado en el grupo control. Conclusión: Por lo que a la motilidad gastropilórica-duodenal tras PPG se refiere, no se precisa conservar la rama pilórica del n. Vago. La estasis gástrica durante el periodo postoperatorio precoz se debe a las contracciones tónicas y fásicas del píloro.

The peptide hormone xenin induces gallbladder contractions in conscious dogs.

Abstract  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 xenins action was cholinergic, but not the vagal. This novel finding indicates a new role of xenin.

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.