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The effects of intracellular Cl- concentration ([Cl-]i) on acetylcholine (ACh)-stimulated exocytosis were studied in guinea pig antral mucous cells by video microscopy. ACh activated Ca2+-regulated exocytosis (an initial phase followed by a sustained phase). Bumetanide (20 μM) or a Cl- -free (NO3-) solution enhanced it; in contrast, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, a Cl- channel blocker) decreased it and eliminated the enhancement induced by bumetanide or NO3- solution. ACh and Ca2+ dose-response studies demonstrated that NO3- solution does not shift their dose-response curves, and ATP depletion studies by dinitrophenol or anoxia demonstrated that exposure of NO3- solution prior to ATP depletion induced an enhanced initial phase followed by a sustained phase, whereas exposure of NO3- solution after ATP depletion induced only a sustained phase. Intra-cellular Ca2+ concentration ([Ca2+]i) measurements showed that bumetanide and NO3- solution enhanced the ACh-stimulated [Ca2+]i increase. Measurements of [Cl-]i revealed that ACh decreases [Cl-]i and that bumetanide and NO3- solution decreased [Cl-]i and enhanced the ACh-evoked [Cl-]i decrease; in contrast, NPPB increased [Cl-]i and inhibited the [Cl-]i decrease induced by ACh, bumetanide, or NO3- solution. These suggest that [Cl-]i modulates [Ca2+]i increase and ATP-dependent priming. In conclusion, a decrease in [Cl-]i accelerates ATP-dependent priming and [Ca2+]i increase, which enhance Ca2+-regulated exocytosis in ACh-stimulated antral mucous cells. [ABSTRACT FROM AUTHOR]

Prostaglandin E2 (PGE2), which is generated by two isoforms of cyclo-oxygenase (COX1 and COX2), is a key mediator in gastric mucosal defense. In the present study, antral mucosa of guinea-pigs was incubated with various agonists or antagonists in a medium, the PGE2 concentration of which was measured using a PGE2 EIA kit. Prostaglandin E2 was released from the antral mucosa spontaneously (basal PGE2 release) and acetylcholine (ACh, 10 μm) enhanced the PGE2 release (ACh-stimulated PGE2 release) was mediated via intracellular Ca2+ concentration ([Ca2+]i). Arachidonic acid enhanced both forms of PGE2 release, and a phospholipase A2 inhibitor (amylcinnamoyl anthranilic acid) and COX inhibitors (acetylsalicylic acid and indomethacin) decreased them. 5-(4-Chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazol (SC560, 100 nm, a COX1-selective inhibitor) inhibited ACh-stimulated PGE2 release without any decrease in basal PGE2 release. N-(2-Cyclohexyloxy-4-nitrophenyl) methanesulphonamide (NS398, 20 μm, a COX2-selective inhibitor) decreased basal PGE2 release without any reduction of ACh-stimulated PGE2 release. However, ionomycin (a Ca2+ ionophore) increased PGE2 release from antral mucosa in the presence of SC560 or NS398, suggesting that COX1 and COX2 are regulated by [Ca2+]i. These findings indicate that COX1-containing cells have ACh receptors but COX2-containing cells do not. Moreover, in isolated antral epithelial cells, SC560 decreased basal and ACh-stimulated PGE2 release, but NS398 did not. In conclusion, in antral mucosa, basal PGE2 release is mainly maintained by COX2 of non-epithelial cells, and ACh-stimulated PGE2 release is maintained by COX1 of epithelial cells. [ABSTRACT FROM AUTHOR]

Ca2+-regulated exocytosis is enhanced by an autocrine mechanism via the PGE2–cAMP pathway in antral mucous cells of guinea-pigs. The inhibition of the PGE2–cAMP pathway by H-89 (an inhibitor of protein kinase A, PKA) or aspirin (ASA, an inhibitor of cyclo-oxygenase, COX) decreased the frequency of ACh-stimulated exocytotic events by 60%. Indomethacin (IDM, an inhibitor of COX), however, decreased the frequency of ACh-stimulated exocytotic events only by 30%. Moreover, IDM increased the frequency of ACh-stimulated exocytotic events by 50% in H-89-treated or ASA-treated cells. IDM inhibits the synthesis of Prostaglandin (PGG/H) and (15R)-15-hydroxy-5,8,11 cis-13-trans-eicosatetraenoic acid (15R-HPETE), while ASA inhibits only the synthesis of PGG/H. Thus, IDM may accumulate arachidonic acid (AA). AACOCF3 or N-( p-amylcinnamoyl) anthranilic acid (ACA; both inhibitors of phospholipase A2, PLA2), which inhibits AA synthesis, decreased the frequency of ACh-stimulated exocytotic events by 60%. IDM, however, did not increase the frequency in AACOCF3-treated cells. AA increased the frequency of ACh-stimulated exocytotic events in AACOCF3- or ASA-treated cells, similar to IDM in ASA- and H-89-treated cells. Moreover, in the presence of AA, IDM did not increase the frequency of ACh-stimulated exocytotic events in ASA-treated cells. The PGE2 release from antral mucosa indicates that inhibition of PLA2 by ACA inhibits the AA accumulation in unstimulated and ACh-stimulated antral mucosa. The dose–response study of AA and IDM demonstrated that the concentration of intracellular AA accumulated by IDM is less than 100 nm. In conclusion, IDM modulates the ACh-stimulated exocytosis via AA accumulation in antral mucous cells. [ABSTRACT FROM AUTHOR]

Terbutaline (10 µM) induced a triphasic volume change in alveolar type II (AT-II) cells: an initial shrinkage (initial phase) followed by cell swelling (second phase) and a gradual shrinkage (third phase). The present study demonstrated that the initial and the third phases are evoked by the activation of K+ and Cl- channels and the second phase is evoked by the activation of Na+ and Cl- channels. Ouabain blocked the third phase, although it did not block the initial and second phases. This suggests that the third phase is triggered by the Na+-K+ pump. Tetraethylammonium (TEA, a K+terbutaline-stimulated third phase, although quinidine, another K+ channel blocker, increased the volume of AT-II cells. The TEA-induced cell shrinkage was inhibited by ouabain, suggesting that TEA increases Na+-K+ pump activity. Ba2+, 2,3-diaminopyridine and a high [K+] ]o] (30 mM) similarly decreased the volume of AT-II cells. These findings suggest that depolarization induced by TEA increases Na+-K+ pump activity, which increases [K+]i. This [K+]i increase, in turn, hyperpolarizes membrane potential. Valinomycin (a K+ ionophore), which induces hyperpolarization, decreased the volume of AT-II cells and enhanced the third phase in these cells. In conclusion, in terbutaline-stimulated AT-II cells, an increase in Na+-K+ pump activity hyperpolarizes the membrane potential and triggers the third phase by switching net ion transport from NaCl entry to KCl release. [ABSTRACT FROM AUTHOR]

Focuses on a study on the cAMP modulation of calcium&sup2+;-regulated exocytosis in ACh-stimulated antral mucous cells of guinea pig. Materials and methods; Results; Discussion.

The effects of intracellular Cl- concentration ([Cl-]i) on acetylcholine (ACh)-stimulated exocytosis were studied in guinea pig antral mucous cells by video microscopy. ACh activated Ca2+-regulated exocytosis (an initial phase followed by a sustained phase). Bumetanide (20 microM) or a Cl- -free (NO3-) solution enhanced it; in contrast, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, a Cl- channel blocker) decreased it and eliminated the enhancement induced by bumetanide or NO3- solution. ACh and Ca2+ dose-response studies demonstrated that NO3- solution does not shift their dose-response curves, and ATP depletion studies by dinitrophenol or anoxia demonstrated that exposure of NO3- solution prior to ATP depletion induced an enhanced initial phase followed by a sustained phase, whereas exposure of NO3- solution after ATP depletion induced only a sustained phase. Intracellular Ca2+ concentration ([Ca2+]i) measurements showed that bumetanide and NO3- solution enhanced the ACh-stimulated [Ca2+]i increase. Measurements of [Cl-]i revealed that ACh decreases [Cl-]i and that bumetanide and NO3- solution decreased [Cl-]i and enhanced the ACh-evoked [Cl-]i decrease; in contrast, NPPB increased [Cl-]i and inhibited the [Cl-]i decrease induced by ACh, bumetanide, or NO3- solution. These suggest that [Cl-]i modulates [Ca2+]i increase and ATP-dependent priming. In conclusion, a decrease in [Cl-]i accelerates ATP-dependent priming and [Ca2+]i increase, which enhance Ca2+-regulated exocytosis in ACh-stimulated antral mucous cells.

Purpose: To evaluate the association between dihydropyrimidine dehydrogenase (DPD) and thymidylate synthase (TS) levels in primary gastric tumors and clinical response to S-1 or S-1 plus irinotecan in patients with unresectable advanced gastric cancer, and to investigate the molecular mechanism of augmented antitumor activity of the combination using human gastric cancer xenografts with high TS activity., Materials and Methods: TS mRNA expression and DPD mRNA expression were measured by reverse transcription polymerase chain reaction in initial primary cancer biopsy specimens in 29 patients with advanced gastric cancer who had received S-1 alone (n=18) or in combination with irinotecan (n=11). In an experimental study, antitumor effects of S-1, irinotecan, and the combination were assessed in mice bearing human gastric tumors with high TS expression (4-1-ST and AZ-521 tumors) and low TS expression (SC-2 tumors), and activities of 5-fluorouracil-metabolizing enzymes were measured., Results: In the clinical study, a strong statistical association between high TS expression and clinical resistance to S-1 alone was found (P = .009). In the experimental studies, S-1 plus irinotecan showed augmented antitumor activity against tumors with high TS activity (P < .01) compared with either agent alone. A potential mechanism for this effect was suggested by the significant reduction in TS activity observed following irinotecan administration in tumors with high TS activity., Conclusion: This study suggests that, via down-regulation of TS by irinotecan treatment, combination chemotherapy with S-1 and irinotecan could be effective in gastric cancer patients with high TS levels.

Aim: To evaluate the effect of pyrrolidine dithio-carbamate (PDTC; an NF-kappaB inhibitor) administered at low (50 mg/kg) and high (100 mg/kg) doses in suppressing colitis in mice with dextran sodium sulfate (DSS)-induced colitis., Methods: Mice were divided into a DSS-untreated group (normal group), DSS-treated control group, DSS+PDTC-treated group I (low-dose group), and DSS+PDTC-treated group II (high-dose group). In each group, the disease activity index score (DAI score), intestinal length, histological score, and the levels of activated NF-kappaB and inflammatory cytokines (IL-1beta and TNF-alpha) in tissue were measured., Results: The DSS+PDTC-treated group II exhibited suppression of shortening of intestinal length and reduction of DAI score. Activated NF-kappaB level and IL-1beta and TNF-alpha levels were significantly lower in DSS+PDTC-treated group II., Conclusion: These findings suggest that PDTC is useful for the treatment of ulcerative colitis.

In guinea pig antral mucous cells, ACh stimulates the Ca(2+)-regulated exocytosis, which has a characteristics feature: an initial transient phase followed by a sustained phase. The effects of cGMP on ACh-stimulated exocytosis were studied in guinea pig antral mucous cells using video microscopy. cGMP enhanced the frequency of ACh-stimulated exocytotic events, whereas cGMP alone did not induce any exocytotic events under the ACh-unstimulated condition. cGMP did not stimulate either Ca(2+) mobilization or cAMP accumulation. The Ca(2+) dose-response studies demonstrated that cGMP shifted the dose-response curve upward with no shift to the lower concentration. This indicates that cGMP increased maximal responsiveness of the Ca(2+)-regulated exocytosis, but not the Ca(2+) sensitivity. Moreover, under a condition of ATP depletion by dinitrophenol (DNP) or anoxia (N(2) bubbling), ACh evoked only a sustained phase in exocytotic events with no initial transient phase. However, ACh evoked an initial transient phase followed by a sustained phase with addition of cGMP before ATP depletion, whereas only a sustained phase was evoked in a case of cGMP addition after ATP depletion. Thus cGMP-induced enhancement in ACh-stimulated exocytotic events requires ATP, suggesting that cGMP modulates ATP-dependent priming of Ca(2+)-regulated exocytosis in antral mucous cells. In conclusion, cGMP increases the number of primed granules via acceleration of the ATP-dependent priming, which enhances the Ca(2+)-regulated exocytosis stimulated by ACh.

Various hepato-biliary complications are an increased incidence in patients with inflammatory bowel disease, and portal bacteremia is well documented in patients with ulcerative colitis (UC). However, few reports mention UC in association with liver abscesses. Recently, there are several reports describing cytomegalovirus (CMV) infection in association with disease exacerbation and steroid refractoriness in patients with UC. Here we present a case of refractory UC accompanied with multiple liver abscesses and CMV colitis. The patient, a 72-year-old male, with a five-year history of repeated admissions to our hospital for UC, presented with an exacerbation of his UC. Sigmoidoscopy performed on admission suggested that his UC was exacerbated, then he was given prednisolone and mesalazine orally, and betamethasone enemas. However, he had exacerbated symptoms. Repeat sigmoidoscopy revealed multiple longitudinal ulcers and pseudopolyps in the rectosigmoid colon. Although immunohistochemical staining of biopsy specimens and the serum testing for antigenemia were negative on admission and after the repeat sigmoidoscopy, they became histologically positive for CMV. Nonetheless, the patient developed spiking fevers, soon after ganciclovir was administered. Laboratory studies revealed an increased white cell count with left shift, and Enterococcus fecalis grew in blood cultures. An abdominal computed tomography (CT) scan was obtained and the diagnosis of liver abscesses associated with UC was made, based on CT results. The hepatic abscesses were successfully treated with intravenous meropenem for 6 wk, without further percutaneous drainage. To our knowledge, this is the first reported case of multiple liver abscesses that develop during UC exacerbation complicated by CMV colitis.

The effects of indomethacin (IDM) and aspirin (ASA) on ACh (10 microM) -stimulated exocytotic events were studied in guinea pig antral mucous cells by using video optical microscopy. IDM or ASA, which inhibits cyclooxygenase (COX), decreased the frequency of ACh-stimulated exocytotic events by 30% or 60%, respectively. The extent of inhibition induced by ASA (60%) decreased by 30% when IDM or arachidonic acid (AA, the substrate of COX) was added. IDM, unlike ASA, appears to induce the accumulation of AA, which enhances the frequency of ACh-stimulated exocytotic events in ASA-treated cells. ONO-8713 (100 microM; an inhibitor of the EP1-EP4 prostaglandin receptors) and N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide, HCl (H-89, 20 microM; an inhibitor of PKA) also decreased the frequency of ACh-stimulated exocytotic events by 60%. However, the supplementation of PGE(2) (1 microM) prevented the IDM-induced decrease in the frequency of ACh-stimulated exocytotic events. SC-560 (an inhibitor of COX-1) decreased the frequency of ACh-stimulated exocytotic events by 30%, but NS-398 (an inhibitor of COX-2) did not. Moreover, IDM decreased the frequency of exocytotic events stimulated by ionomycin, suggesting that COX-1 activity is stimulated by an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)). ACh and ionomycin increased PGE(2) release in antral mucosal cells. In conclusion, in ACh-stimulated antral mucous cells, an increase in [Ca(2+)](i) activates Ca(2+)-regulated exocytotic events and PGE(2) release mediated by COX-1. The released PGE(2) induces the accumulation of cAMP, which enhances the Ca(2+)-regulated exocytosis. The autocrine mechanism mediated by PGE(2) maintains the high-level mucin release from antral mucous cells during ACh stimulation.

Aim: To compare the differences in the endoscopic classification of early colorectal carcinoma (CRC) between Japan and China., Methods: Ten cases of early CRC were included in the study. After reviewing the color pictures of these cases, 5 Japanese endoscopists and 5 Chinese endoscopists made their classificatory diagnosis individually using the current Japanese classification, and indicated their findings on which the diagnosis was based., Results: Some lesions diagnosed by the Japanese endoscopists as IIa or IIa plus IIc, were classified as Is or Isp by the Chinese endoscopists. For superficial lesions consisting of elevation plus central depression, IIa plus depression, IIa plus IIc or IIc plus IIa were classified according to the ratio of elevated area/depressed area. However, international as well as interobserver difference still existed in the classification of such lesions. In addition, most Chinese endoscopists overlooked slightly depressed part on the top of a protruded lesion. Laterally spreading tumor, a special type of IIa, was identified as LST by some Japanese endoscopists., Conclusion: Discrepancies on macroscopic classification for early CRC do exist between Japanese and Chinese endoscopists, which are found not only in terminology but also in recognition of some lesions. In order to develop a universal classification, it needs for international communication and cooperation.

Effects of cAMP accumulation on ATP-dependent priming and Ca(2+)-dependent fusion in Ca(2+)-regulated exocytosis were examined in antral mucous cells of guinea pigs by using video-enhanced contrast microscopy. The Ca(2+)-regulated exocytosis activated by 1 microM ACh consisted of two phases, an initial transient phase followed by a sustained phase, which were potentiated by cAMP accumulation. Depletion of ATP by 100 microM dinitrophenol (uncoupler of oxidative phosphorylation) or anoxia induced the sustained phase without the initial transient phase in Ca(2+)-regulated exocytosis. However, accumulation of cAMP before depletion of ATP induced and potentiated an initial transient phase followed by a sustained phase in Ca(2+)-regulated exocytosis. This suggests that the initial transient phase of Ca(2+)-regulated exocytosis is induced by fusion of all primed granules maintained by ATP and that accumulation of cAMP accelerates ATP-dependent priming of the exocytotic cycle. Moreover, ACh and Ca(2+) dose-response studies showed that accumulation of cAMP shifted the dose-response curves to the low concentration side, suggesting that it increases Ca(2+) sensitivity in the fusion of the exocytotic cycle. In conclusion, cAMP accumulation increases the number of primed granules and Ca(2+) sensitivity of the fusion, which potentiates Ca(2+)-regulated exocytosis in antral mucous cells.