Expansion of indications for endoscopic treatment of undifferentiated mucosal gastric cancer: analysis of intramucosal spread in resected specimens.

PURPOSE: The aim of this study was to pathologically investigate the developmental pattern of undifferentiated mucosal gastric cancer and to determine safe surgical margins for curative resection by endoscopic resection. RESULTS: Intramucosal cancer spread, or the width of the proliferative zone, was pathologically investigated in 47 cases of undifferentiated mucosal gastric cancer of size 20 mm or smaller without ulceration (scars). The 47 cases comprised 40 IIc and 7 IIb cases. The IIc cases consisted of 5 (12.5%) of intermediate-layer type (cancer localized at the intermediate layer of the mucosa), 31 (77.5%) of superficial type, and 4 of whole-layer type (10%). The IIb cases consisted of six of intermediate-layer type (85.7%) and one of superficial type (14.3%). The width of the proliferative zone in the 40 IIc cases ranged from 0 to 2,390 microm (average 605.5 microm). There was no significant correlation between width of proliferative zone and background mucosa. With regard to lesion size, average width was 243.6 microm in cases with longest diameter 5 mm. CONCLUSIONS: In endoscopic treatment of undifferentiated mucosal gastric cancer of size 20 mm or smaller without ulceration (scars), the lateral safety margin should be 3 mm or more.

Functional evaluation of the grafted wall with porcine-derived small intestinal submucosa (SIS) to a stomach defect in rats.

BACKGROUND: Small intestinal submucosa (SIS) represents a novel bio-scaffolding material that may be used to repair hollow-organ defects. However, it is unclear whether neurophysiologic responses return to SIS-grafted areas in the gut. We evaluated the functional recovery of a stomach defect grafted with the porcine-derived SIS. METHODS: Twelve rats had a full-thickness defect created in the stomach. SIS was secured to the gastric wall. After 6 months, muscle strips were harvested from within the grafted area to perform both a histologic and a functional study. Additional full-thickness muscle strips were harvested from the posterior in the same stomach as controls. A dose response curve was obtained with carbachol (CCH) or sodium nitroprusside (SNP). Activation of intrinsic nerves was achieved by electrical field stimulation (EFS). RESULTS: The response to CCH and amplitude in EFS showed tonic contraction in both controls and SIS strips in a concentration-dependent and frequency-dependent manner. The magnitude after each stimulation was significantly lower in SIS strips compared with controls (P < .01). However, the contraction ratio of EFS to ED(50) of CCH was not significantly different between the groups. Additionally, SNP produced relaxation in both strips in a concentration-dependent manner. Histologic findings revealed that an insufficient amount of smooth-muscle cells existed in the muscularis propria, whereas compensated growth was observed in the submucosa with nerve regeneration. CONCLUSIONS: This study demonstrates that SIS provides a template for nerve migration to the graft in the rodent stomach. Innervations showed a similar distribution to that observed in the controls. The clinical implications of such findings warrant additional investigation.

[Therapeutic strategy for hemorrhagic radiation proctitis--the optimum condition of argon plasma coagulation (APC)].

AIM: This study was performed to clarify the optimum condition of argon plasma coagulation (APC) to treat hemorrhagic radiation proctitis. SUBJECTS: Among 25 patients with hemorrhagic radiation proctitis treated in the Cancer Institute Hospital between December 2000 and May 2004, 18 were followed-up for more than 6 months. The clinical courses of these 18 patients were analyzed retrospectively. METHODS: Proctoscopic findings of the hemorrhagic lesions were categorized as type-A (localized dilated veins, n = 6) , type-B (diffuse dilated veins, n = 6), and type-C (dilated veins associated with ulcers orerosions, n = 6). APC was applied for 5-10 seconds with the power of 40 W and the argon flow of 1.0 l/min (high power APC), or for 1-2 seconds with the power of 40 W and the argon flow of 0.6 l/min (low power APC). RESULTS: Type-A and B patients were successfully treated with either low or high power APC without any serious complications. But some type-C patients treated with high power APC showed serious complications such as proctovaginal fistula or prolonged ulceration. No recurrence patients were 89% (16/18) during the mean follow up period of 18 +/- 9.9 months. CONCLUSION: APC therapy for hemorrhagic radiation-proctitis was useful, but the pathologic healing process and consequence were different by rectal mucosal weakness. It is necessary for the therapeutic strategy to be put up and down according to proctoscopic findings. As for the optimum condision APC short cauterization by low power setting was more recommended.

Effects of acupuncture on vasopressin-induced emesis in conscious dogs.

Although acupuncture has a significant clinical benefit, the mechanism of acupuncture remains unclear. Vasopressin, a posterior pituitary hormone, is involved in nausea and vomiting in humans and dogs. To investigate the antiemetic effects of acupuncture on vasopressin-induced emesis, gastroduodenal motor activity and the frequency of retching and vomiting were simultaneously recorded in conscious dogs. In seven dogs, four force transducers were implanted on the serosal surfaces of the gastric body, antrum, pylorus, and duodenum. Gastroduodenal motility was continuously monitored throughout the experiment. Vasopressin was intravenously infused at a dose of 0.1 U x kg(-1) x min(-1) for 20 min. Electroacupuncture (EA, 1-30 Hz) at pericardium-6 (PC6), bladder-21 (BL21), or stomach-36 (ST36) was performed before, during, and after the vasopressin infusion. To investigate whether the opioid pathway is involved in EA-induced antiemetic effects, naloxone (a central and peripheral opioid receptor antagonist) or naloxone methiodide (a peripheral opioid receptor antagonist) was administered before, during, and after EA and vasopressin infusion. Intravenous infusion of vasopressin induced retching and vomiting in all dogs tested. Retrograde peristaltic contractions occurred before the onset of retching and vomiting. EA (10 Hz) at PC6 significantly reduced the number of episodes of retching and vomiting. EA at PC6 also suppressed retrograde peristaltic contractions. In contrast, EA at BL21 or ST36 had no antiemetic effects. The antiemetic effect of EA was abolished by pretreatment with naloxone but not naloxone methiodide. It is suggested that the antiemetic effect of acupuncture is mediated via the central opioid pathway.

Dual effects of acupuncture on gastric motility in conscious rats.

The effects of manual acupuncture on gastric motility were investigated in 35 conscious rats implanted with a strain gauge transducer. Twenty (57.1%) rats showed no cyclic groupings of strong contractions (type A), whereas 15 (42.9%) rats showed the phase III-like contractions of the migrating motor complex (type B) in the fasting gastric motility. Acupuncture at the stomach (ST)-36 (Zusanli), but not on the back [Weishu, bladder (BL)-21], increased the peak amplitude of contractions to 172.4 +/- 25.6% of basal in the type A rats (n = 20, P < 0.05). On the other hand, the motility index for 60 min after the acupuncture was not affected by the acupuncture in this group. On the contrary, acupuncture decreased the peak amplitude and motility index to 72.9 +/- 14.0% and 73.6 +/- 16.2% in the type B rats (n = 15, P < 0.05), respectively. The stimulatory and inhibitory effects of acupuncture observed in each type were reproducible on the separate days. In 70% of type A rats, acupuncture induced strong phase III-like contractions lasting for over 3 h that were abolished by atropine, hexamethonium, atropine methyl bromide, and vagotomy. Naloxone significantly shortened the duration of the stimulatory effects from 3.52 +/- 0.21 to 1.02 +/- 0.15 h (n = 3, P < 0.05). These results suggest that acupuncture at ST-36 induces dual effects, either stimulatory or inhibitory, on gastric motility. The stimulatory effects are mediated in part via vagal efferent and opioid pathways.

Short-chain fatty acids stimulate colonic transit via intraluminal 5-HT release in rats.

We studied whether physiological concentration of short-chain fatty acids (SCFAs) affects colonic transit and colonic motility in conscious rats. Intraluminal administration of SCFAs (100-200 mM) into the proximal colon significantly accelerated colonic transit. The stimulatory effect of SCFAs on colonic transit was abolished by perivagal capsaicin treatment, atropine, hexamethonium, and vagotomy, but not by guanethidine. The stimulatory effect of SCFAs on colonic transit was also abolished by intraluminal pretreatment with lidocaine and a 5-hydroxytryptamine (HT)(3) receptor antagonist. Intraluminal administration of SCFAs provoked contractions at the proximal colon, which migrated to the mid- and distal colon. SCFAs caused a significant increase in the luminal concentration of 5-HT of the vascularly isolated and luminally perfused rat colon ex vivo. It is suggested that the release of 5-HT from enterochromaffin cells in response to SCFAs stimulates 5-HT(3) receptors located on the vagal sensory fibers. The sensory information is transferred to the vagal efferent and stimulates the release of acetylcholine from the colonic myenteric plexus, resulting in muscle contraction.

Neural mechanism of acupuncture-induced gastric relaxations in rats.

Acupuncture has been used to treat gastrointestinal symptoms in China for more than 3000 years. However, the mechanism of the beneficial effects of acupuncture remains unknown. Strain gauge transducers were implanted on the serosal surface of the stomach to record circular muscle contractions in thiobutabarbital-anesthetized rats. Acupuncture on the right lower abdomen caused a transient relaxation of the stomach. Acupuncture-induced gastric relaxations were abolished by guanethidine, propranolol, splanchnic ganglionectomy, spinal cord transection, and spinomedullary transection. In contrast, N(G)-nitro-L-arginine, phentolamine, truncal vagotomy, and pontomedullary transection had no effect. Acupuncture increased the number of c-Fos immunopositive cells at the ventrolateral medulla (VLM). It is concluded that acupuncture-induced gastric relaxations are mediated via the somatosympathetic reflex. Its afferent limb is composed of abdominal cutaneous and muscle afferent nerves. Its efferent limb is the gastric sympathetic nerve and the reflex center is within the medulla. VLM neurons may play an important role in mediating this reflex.