[The clinicopathological analysis of lymph node metastasis of gastric cancer]

One hundred-twenty-one cases of curative resection for gastric cancer with lymph node metastasis were analyzed to determine the prognostic value of the nodal stage (n), number of metastatic lymph nodes, maximum diameter of metastatic lymph nodes, micrometastasis of lymph nodes, histological type of lymph node metastasis, extranodular invasion and infiltration into lymphatic vessels around metastatic lymph nodes. In patients with a higher nodal stage the survival rate was lower and the nodal stage was a good prognostic indicator. Inpatients who had 7 or more metastatic lymph nodes or in whom the maximum diameter of the metastatic lymph nodes was over 15 mm or who had not only micrometastasis of lymph nodes, the survival rate was lower. These results suggest that quantitative analysis of metastatic lymph nodes is necessary. In patients who had nudifferentiated type metastatic lesions of lymph nodes, the survival rate was lower than in those with the differentiated type and the difference was larger than for the primary lesion. In patients who had extranodular invasion or infiltration into lymphatic vessels around metastatic lymph nodes, the survival rate was decreased. These results suggest that histopathological analysis of metastatic lymph nodes is necessary.

The structure and unusual pH dependence of plastocyanin from the fern Dryopteris crassirhizoma. The protonation of an active site histidine is hindered by pi-pi interactions

Spectroscopic properties, amino acid sequence, electron transfer kinetics, and crystal structures of the oxidized (at 1.7 A resolution) and reduced form (at 1.8 A resolution) of a novel plastocyanin from the fern Dryopteris crassirhizoma are presented. Kinetic studies show that the reduced form of Dryopteris plastocyanin remains redox-active at low pH, under conditions where the oxidation of the reduced form of other plastocyanins is inhibited by the protonation of a solvent-exposed active site residue, His87 (equivalent to His90 in Dryopteris plastocyanin). The x-ray crystal structure analysis of Dryopteris plastocyanin reveals pi-pi stacking between Phe12 and His90, suggesting that the active site is uniquely protected against inactivation. Like higher plant plastocyanins, Dryopteris plastocyanin has an acidic patch, but this patch is located closer to the solvent-exposed active site His residue, and the total number of acidic residues is smaller. In the reactions of Dryopteris plastocyanin with inorganic redox reagents, the acidic patch (the "remote" site) and the hydrophobic patch surrounding His90 (the "adjacent" site) are equally efficient for electron transfer. These results indicate the significance of the lack of protonation at the active site of Dryopteris plastocyanin, the equivalence of the two electron transfer sites in this protein, and a possibility of obtaining a novel insight into the photosynthetic electron transfer system of the first vascular plant fern, including its molecular evolutionary aspects. This is the first report on the characterization of plastocyanin and the first three-dimensional protein structure from fern plant.

Stent grafting for aortic dissection

We report the successful treatment of a patient with Stanford type B aortic dissection, "thrombosed" type with ulcer-like projections, by insertion of a stent-graft. The false lumen completely disappeared within 1 year after surgery. This maturing procedure is promising in the treatment of thrombosed, aggravated aortic dissection.

Clinical study on arthroplasties for osteoarthritic hip by quantitative gait analysis. Comparison between total hip arthroplasty and bipolar endoprosthetic arthroplasty

The present study was undertaken to serially observe gait of patients after hip arthroplasty, using quantitative gait analysis, and to compare it between patients after total hip arthroplasty (THA) and those after bipolar endoprosthetic arthroplasty (BEA). The subjects were 53 women with unilateral osteoarthritis of the hip. Thirty-one of them underwent THA (mean age: 59.5 years) and 22 underwent BEA (mean age: 58.0 years). The stance time and characteristic parameters calculated from the vertical component of floor reaction force (FRF) were analyzed by use of FRF plate. The stance time, which indirectly represents the walking speed, tended to decrease for one year after THA and for 3 years after BEA. The decrease in this parameter was greater on the unaffected side than on the affected side. The deceleration effect and the weighing-off effect are indicators useful for observation of gait recovery. Significant differences in these indicators between the unaffected and affected sides were seen for one year after THA and 3 years after BEA. This indicates that cadence and balance of the gait recovers earlier after THA than after BEA.

[Unilateral visual field defect due to optic nerve compression by sclerotic internal carotid artery: a case report]

A case of unilateral visual field defect due to optic nerve compression by a sclerotic internal carotid artery was reported. A 71-year-old woman was admitted to our department because of constricted visual field of the right eye. MRI showed elevation of the right optic nerve compressed by an internal carotid artery. The right carotid angiography revealed elevation and distortion of the C1-2 portion. Frontal craniotomy was carried out and the optic nerve was visualized on this side. The right optic nerve was found to have been compressed by the sclerotic internal carotid artery. The optic canal was then unroofed. The post-operative course was uneventful. The visual field was improved. When last seen 6 months after surgery, her visual field remained in the improved condition. Nasal field abnormalities are most frequently encountered in retinal and anterior optic nerve pathology. Our success in improving the visual field disturbance may be accounted for by the fact that the preoperative period was short and the operation was performed before atrophy of ocular fundi occurred. Nasal field loss caused by intracranial lesions of the optic pathway is rare. It is probably impossible to determine degree of the symptomatology caused by direct-pressure compression as opposed to that caused by ischemia secondary to occlusion of small arterial supply branches. Vascular compressive neuropathy of optic nerve should not be diagnosed simply by the radiological finding of the optic nerve dislocation. However, optic nerve compression by surrounding arteries should be remembered as one of the possible causes of visual field defect which needs to be treated surgically.

[Primary splenic lymphoma with hypoplastic bone marrow]

A 44-year-old man was admitted because of persistent fever and pancytopenia. Because his bone marrow was hypoplastic and the karyotype of his marrow cells was normal, he was given a diagnosis of aplastic anemia, and treated with glucocorticoids and granulocyte colony-stimulating factor. Splenomegaly was later found and a splenectomy performed: pathological findings on resected tissue specimens disclosed non-Hodgkin's lymphoma, B-cell diffuse large. The patient was transferred to our hospital, where a bone marrow biopsy revealed lymphoma cells infiltrating his hypoplastic marrow. Complex chromosomal abnormalities were detected in marrow cells, but no lymphadenopathy was observed. A diagnosis of primary splenic lymphoma with infiltration of lymphoma cells into bone marrow was made, and chemotherapy was accordingly started. After multiple cycles of chemotherapy, the patient's marrow recovered to a normal state and his karyotype abnormalities disappeared. Six months later, pancytopenia reappeared and lymphoma cells were again detected in the patient's bone marrow. We reasoned that the hypoplastic state of his bone marrow was associated with the lymphoma, and that cytokines, including interferon-gamma, may have been responsible for this association.

Interaction of the new histamine H2-receptor antagonist pibutidine hydrochloride with canine cloned H2-receptor expressed cells

The effect of a new histamine H2-receptor antagonist, pibutidine hydrochloride ((Z)-3-amino-4-{4-{4-[(piperidinomethyl)pyrid-2-yl]oxy} but-2-enylamino}cyclobut-3-ene-1,2-dione monohydrochloride, CAS 126463-66-9, IT-066 displaced the binding of [3H]tiotidine to cells transfected with the wild-type H2-receptor in a concentration-dependent manner. Compared with the 50% inhibitory concentration values (IC50) among five H2-receptor antagonists tested, the value of IT-066 was lowest. The inhibitory effect of IT-066 was enhanced by preincubation of IT-066 with the cells, and preincubation for 60 min increased potency about 2-fold. Famotidine also has such effects. When H2-receptor transfected cells were treated with IT-066 for 30 min, the inhibitory effect of IT-066 on the [3H]tiotidine binding still remained even after the cells were extensively washed. Scatchard plot analysis supported the non-competitive and irreversible action of IT-066. When the canine mutated H2-receptor-expressed cells were used, which have substituted amino acid of 190Alanine (Ala; position: 190th amino acid) for 190Threonine (Thr) in the fifth transmembrane domain, IT-066 also inhibited [3H]tiotidine binding to the cells concentration-dependently. However, in the case of the 190Ala mutated cells, the inhibitory effect of IT-066 attenuated with a decrease in maximal response after washing of the cells. These results show that IT-066 could tightly bind H2-receptor in a time-dependent manner and suggest the possibility that the irreversible inhibition of IT-066 is important in the interaction with 190Thr in the fifth transmembrane domain of H2-receptor.

Reproductive study. II: Prenatal and postnatal development study with candoxatril in Sprague-Dawley rats

Candoxatril, a prodrug for candoxatrilat, a selective inhibitor of neutral endopeptidase, was administered orally to groups of 24 female rats at doses of 0, 120, 400 or 1200 mg/kg/day from gestation day 6 to lactation day 21 to assess effects on pre- and postnatal development of F1 offspring. All dams were allowed to litter and to raise their F1 offspring until lactation day 21. The F1 offspring were examined for postnatal developmental indices, reflex behaviors and memory. A functional observational battery (FOB) was also conducted. A marked increase in spontaneous activity of the dams was observed in all candoxatril-treated groups. Maternal body weight gain was decreased in the 400 and 1200 mg/kg/day groups during the treatment periods. No significant differences were found for reproductive parameters. The male and female pups in the 1200 mg/kg/day group had significantly lower body weights beginning on postnatal days 21 and 14, respectively, through to the end of the study. There were no drug-related effects on pre- and postnatal developmental indices, FOB, sensory function tests or memory test. The no observed adverse effect levels were 120 and 400 mg/kg/day for the F0 dams and F1 offspring, respectively.

Multicentric Castleman's disease associated with renal amyloidosis and pure red cell aplasia

A 50-year-old man was admitted suffering from severe anemia and renal dysfunction. He had been admitted for the first time at the age of 49, and was diagnosed with multicentric Castleman's disease (MCD) and secondary amyloidosis. At that time, marked erythroid hypoplasia was demonstrated by both aspiration and biopsy of bone marrow. A diagnosis of pure red-cell aplasia (PRCA) was made. Immunosuppressive agents improved his symptoms and laboratory data. We report here a very rare case of PRCA following MCD and amyloidosis, and with reference to the literature, we discuss the relation between MCD and related diseases.

[Mantle cell lymphoma with marked lymphocytosis at the presentation and with discordant morphology between the lymph node and peripheral blood]

A 72-year-old man was referred to our hospital because of lymphadenopathy, splenomegaly, and leukocytosis. His WBC count was 54,300/microliter, with 89.6% atypical lymphocytes two to three times the diameter of red blood cells, cleaved nuclei, and one or two nucleoli. A lymph node specimen revealed a vaguely nodular pattern, and the diagnosis of mantle cell lymphoma (MCL) was made. The lymphoma cells appeared smaller and more mature than the leukemic cells. The phenotype of the peripheral blood and the lymph node cells was CD5+ CD10- CD19+ CD20+ and the same rearranged JH bands were detected, suggesting that their lymphocytes were of the same origin. In addition, the phenotype of the leukemic cells was CD23+ CD38+ CD43- CD44+ FMC-7+ micro+ chi+. Cytogenetic analysis revealed complex anomalies but not t(11; 14). Cyclin D1 protein was not detected. Because the lymphocyte morphology of the peripheral blood and lymph nodes was discordant, we speculated that variant large cells had proliferated mainly in the peripheral blood. The patient achieved a partial response after 6 courses of CHOP regimen, and was then placed on a COP regimen. He seemed to have MCL, but the following findings were unusual: marked lymphocytosis at initial presentation, discordant morphology, CD5+ CD10- CD23+ CD43- phenotype with neither t(11; 14) or cyclin D1 over-expression.

Carboxyflavins, novel inhibitors of Taq DNA polymerase

Carboxyflavins were found to be potent selective inhibitors of Taq DNA polymerase in a polymerase chain reaction. The inhibitions were dose-dependent, and complete inhibitions were observed at the concentration of 3.0 microM. Carboxyflavins were much less, or not sensitive to the DNA polymerases tested such as calf thymus DNA polymerase alpha, rat DNA polymerase beta, human immunodeficiency virus type 1 reverse transcriptase, the Klenow Fragment of E. coli DNA polymerase I and T4 DNA polymerase. To our knowledge, there is no other report of an agent that selectively inhibits only a thermophilic polymerase. Interestingly, the carboxyflavins were able to prevent DNA synthesis in the murine lymphoid leukemia cell line L1210 in vitro; almost complete inhibitory levels were achieved in the range of less than 10 microM.

Role of nitric oxide and prostaglandin in the protective effect of pibutidine hydrochloride, a novel histamine H2-receptor antagonist, on the gastric mucosal lesions in rats

1. The role of endogenous nitric oxide (NO) and prostaglandins (PGs) in the gastric mucosal protective action of pibutidine hydrochloride (IT-066), a novel histamine H2-receptor antagonist, was investigated in a 0.15 N hydrochloride (HCl) + 60% ethanol (EtOH)-induced gastric lesion model. 2. The 0.15 N HCl + 60% EtOH-induced lesion formation was reduced significantly by IT-066 (3 mg/kg, PO), NOR3 (spontaneous NO releaser; 0.03-0.1 mg/kg, SC) or PGE2 (0.01 mg/kg, PO) but was not reduced by famotidine (1-10 mg/kg, PO). 3. Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) (3 mg/kg, IV), an inhibitor of NO synthase, inhibited the protective action of IT-066 (3 mg/kg, PO), and the inhibitory effect of L-NAME was reversed by L-arginine (300 mg/kg, IV). The protective effect of PGE2 (0.01 mg/kg, PO) was not affected by the pretreatment with L-NAME (3 mg/kg, IV). 4. Infusion of carboxy-PTIO (1 mg/kg/min), a direct NO scavenger, inhibited the protective effect of IT-066 (3 mg/kg, SC) or NOR3 (0.1 mg/kg, SC). Pretreatment with indomethacin (5 mg/kg, SC) markedly reduced the protective effect of IT-066 (3 mg/kg, PO) or NOR3 (0.1 mg/kg, SC). 5. These results suggest that endogenous NO and PGs may be implicated in the gastric mucosal protection induced by IT-066 and that the endogenous PGs may contribute to the protective effect of NO.

Circadian rhythm of Arg-vasopressin contents in the suprachiasmatic nucleus in relation to corticosterone

Circadian rhythms of locomotor activity and adrenal glucocorticoid are controlled by the suprachiasmatic nucleus (SCN), the center of a biological clock, in mammals. Arg-vasopressin (AVP) contents in the SCN play a role in endogenous circadian rhythm during the absence of time cues. The AVP-containing neurons in the SCN are considered to transmit a circadian signal to the other parts of the brain. The circadian rhythms of AVP in the SCN in relation to the plasma corticosterone and locomotor activity were investigated. Under the light-dark cycle, plasma corticosterone levels were reciprocally correlated with the AVP content in the SCN. Under free-running conditions with constant dim light, AVP rhythms were reciprocally synchronized with the locomotor activity. The correlation of AVP with plasma corticosterone is different at different times of the day both under the LD cycle and constant dim light. Dexamethasone (i. p., 0.1 mg/100) increased the AVP contents, and this tendency was significantly greater during the dark period. These results indicate that corticosterone in the blood may regulate the circadian rhythm through AVP variation in the SCN.

Effect of pibutidine hydrochloride on nitric oxide production in rat gastric mucosa

This study examined the effect of pibutidine hydrochloride, a novel histamine H2 receptor antagonist (IT-066), on nitric oxide (NO) production in gastric mucosa by measuring nitrite and nitrate contents. IT-066 (0.3-3 mg/kg, p.o.) and NO donors, sodium nitroprusside (0.3 mg/kg, s.c.) and NOR3 (0.1 mg/kg, s.c.), increased the NO contents in gastric mucosa. Cimetidine (100 mg/kg, p.o.), ranitidine (30 mg/kg, p.o.) and famotidine (10 mg/kg, p.o.) did not significantly affect the NO production. Pretreatment with NG-nitro-L-arginine methyl ester (3 mg/kg, i.v.), a NO synthase inhibitor, decreased the level of IT-066 (3 mg/kg, p.o.)-stimulated NO production. These results suggest that IT-066 stimulated gastric mucosal NO production, and that endogenous NO may be implicated in the pharmacological effect of IT-066.

Usefulness of metyrapone treatment to suppress cancer metastasis facilitated by surgical stress

BACKGROUND

One causative factor of tumor metastasis enhanced by surgical stress is thought to be hypersecretion of endogenous glucocorticoids. This study evaluated the effectiveness of metyrapone treatment and adrenalectomy in preventing the harmful effects of glucocorticoids in the enhancement of tumor metastasis resulting from surgical stress.

METHODS

The effect of dexamethasone on pulmonary metastasis of MRMT-1 cells and on the number of peripheral lymphocytes was evaluated in rats. To evaluate the suppressive effect of adrenalectomy and metyrapone treatment on operation-induced enhancement of metastasis, several parameters such as induction of pulmonary metastasis, serum corticosterone levels, and the number of blood lymphocytes and apoptotic thymocytes were determined.

RESULTS

With dexamethasone treatment, the number of peripheral lymphocytes rapidly decreased; in contrast, pulmonary metastasis increased. The serum corticosterone level was doubled at 1 hour, apoptotic thymocyte numbers were increased about sevenfold at 3 hours and about fourfold at 6 hours, and blood lymphocyte numbers were decreased at 3 hours after laparotomy, which facilitated about a 10-fold increase in the pulmonary metastasis. These changes were almost completely suppressed by preoperative adrenalectomy and metyrapone treatment.

CONCLUSIONS

Preoperative metyrapone treatment, which suppresses hypersecretion of endogenous glucocorticoids as a result of operation, modulates the enhancement of cancer metastases and may be an effective treatment.

Trehalose 6-phosphate production with energy coupling fermentation by yeast cells

We tried a method for the production of trehalose 6-phosphate (T6P) with energy-coupling fermentation by baker's yeast. T6P was produced in a reaction mixture containing glucose, 5'-UMP, MgSO4, inorganic phosphate, and dried cells of baker's yeast as the enzyme preparation, T6P was isolated from the reaction mixture and identified by TLC, HPLC, GC-MS, and enzymatic methods. The reaction conditions suitable for T6P production were investigated. The formation of T6P and its precursors, glucose 6-phosphate and UDPglucose, at various pHs and concentrations of substrates was examined. Accumulation of T6P was maximum with a reaction mixture containing 1 M glucose, 20 mM 5'-UMP, 20 mM MgSO4, 400 mM sodium phosphate buffer (pH 6.2), and 100 mg/ml dried cells of baker's yeast shaken at 37 degrees C for 6 h. The yield of T6P as a percentage of glucose was 11% (mol/mol) under these reaction conditions.

Detection of chimaeric transcripts of the immunoglobulin heavy chain and BCL6 genes by reverse-transcriptase polymerase chain reaction in B-cell non-Hodgkin's lymphomas

T(3;14)(q27;q32) is frequently detected in B-cell non-Hodgkin's lymphomas, especially the diffuse large cell type and the follicular type. The BCL6 gene encoding a putative transcriptional factor which resides on 3q27 rearranges to the immunoglobulin heavy chain (IgH) gene on 14q32 in this chromosomal translocation. The upstream regulatory region of the BCL6 gene is replaced by the IgH gene. Deregulation of the BCL6 gene may contribute to tumourigenesis of these diseases. The rearrangement between the IgH and BCL6 genes generates chimaeric transcripts in which the joining (J) region of the IgH gene fuses to exon 3 of the BCL6 gene. We established a method to detect these chimaeric transcripts by reverse transcriptase polymerase chain reaction (RT-PCR) using the consensus sequence of the J region and the sequence of exon 3 of the BCL6 gene as primers. Using the semi-nested RT-PCR method and a cell line carrying t(3;14)(q27;q32), we detected one lymphoma cell among 10,000 background cells. We detected these chimaeric transcripts in two out of 13 clinical samples by this method. This method can detect t(3;14)(q27;q32) easily, whereas this alteration is frequently overlooked by routine karyotype analysis. Since this technique is sensitive enough to detect a small number of lymphoma cells with this genetic abnormality, it could be employed to detect contaminating lymphoma cells in bone marrow and peripheral blood and minimal residual diseases.

Structure-activity characterization of an H2-receptor antagonist, 3-amino-4-[4-[4-(1-piperidinomethyl)-2-pyridyloxy]-cis-2-++ +butenylamino]- 3-cyclobutene-1,2-dione hydrochloride (T-066), involved in the insurmountable antagonism against histamine-induced positive chronotropic action in guinea pig atria

IT-066 (3-amino-4-[4-[4-(1-piperidinomethyl)-2-pyridyloxy]-cis-2- butenylamino]-3-cyclobutene-1,2-dione hydrochloride), an H2-receptor antagonist, shows highly potent, time-dependent, and irreversible antagonism at H2-receptors. We identified the structurally important parts of IT-066 involved in its interaction with the H2-receptor, and explored its unique mode of action by investigating the H2-receptor blocking action of IT-066 and related compounds in guinea pig isolated atria. IT-066 is structurally divided into three different parts: a tertiary amine and hydrophobic group, a connecting carbon chain, and a polar group. Though the replacement of its pyridine ring with a benzene ring maintained the mode of the H2-receptor blocking action of IT-066, the oxidation of the piperidine ring completely attenuated this blocking action. By replacing the connecting carbon chain of IT-066, cis-2-butene, with butane, trans-2-butene, or 2-butyne, the irreversible antagonism disappeared and the potency was reduced. On the other hand, BMY25368, whose connecting carbon chain is trimethylene, showed irreversible antagonism comparable to that of IT-066. Hydrolysis of the polar group of IT-066 completely attenuated the H2-receptor blocking activity. Among the compounds tested, only the compound that had 3,4-diamino-3-cyclobutene-1,2-dione as a polar group showed time-dependent and insurmountable H2-receptor blocking action. These data suggest the importance of the following structural features of IT-066: the piperidine ring of IT-066 and -NH2 in its polar group are essential for the interaction with the H2-receptor; and the 3,4-diamino-3-cyclobutene-1,2-dione group and the connecting carbon chain of IT-066 are crucial for determining the irreversibility of H2-receptor blocking action, though the connecting carbon chain is replaceable with another chain with appropriate length and configuration.

Iodine-131 MIBG imaging in multiple endocrine neoplasia type 2B

A 16-year-old boy had a swollen neck that was a result of multiple endocrine neoplasia Type 2B (MEN 2B). CT revealed bilateral thyroid tumors, swelling of right cervical lymph nodes, and slight enlargement of the right adrenal gland. I-131 metaiodobenzylguanidine (MIBG) scintigraphy demonstrated increased uptake in the right adrenal gland and the left thyroid tumor, but no abnormal uptake in the right thyroid tumor and the right cervical lymph nodes. Postoperative pathologic findings were consistent with the diagnosis of right adrenal medullary hyperplasia, which is a precursor of pheochromocytoma. In patients with MEN 2B, I-131 MIBG scintigraphy in conjunction with CT of the adrenal glands should be performed to determine the disease stage of the adrenal medullae. In the cervical region, the diagnosis was medullary thyroid carcinoma (MTC) in both thyroid tumors and metastases in the right cervical lymph nodes. The right MTC was more aggressive than the left MTC. It is interesting that not all sites of known MTC take up I-131 MIBG to the same degree.

AVP rhythm in the suprachiasmatic nucleus in relation to locomotor activity under constant light

To examine the roles of Arg-vasopressin (AVP)- and vasoactive intestinal peptide (VIP)-containing neurons in the suprachiasmatic nucleus (SCN) in production of circadian rhythmicity of locomotor activity, variations in the contents of AVP and VIP in punched-out SCN tissue and locomotor activity were measured under a light-dark cycle as well as under conditions of constant light for up to 3 weeks. Under the light-dark cycle, contents of AVP and VIP, and locomotor activity showed marked circadian rhythmicity. Under constant light, AVP content showed circadian rhythmicity until 3 weeks, while VIP rhythm disappeared from the first week with decreases in its content. Locomotor activity showed a free-running circadian rhythm for more than 3 weeks under constant light conditions in most cases. These results suggest that AVP but not VIP in the SCN may be involved in the generation of locomotor activity rhythm under conditions of constant light.

Effect of cold-stress and indomethacin on the biosynthesis of gastric sulfated mucin in rats

The biosynthesis of sulfated mucin in gastric tissue was investigated in cold-stress and indomethacin (CSI)-induced gastric ulcer models. To examine the synthesis of gastric sulfated mucin, [35S]H2SO4 (sulfate) incorporation into gastric mucin was measured. The treatment of CSI inhibited the incorporation of [35S]sulfate after 2 hr. The gastric acid hypersecretion or the formation of severe ulcer was observed at 1 or 4 hr after the CSI-treatment, respectively. Pibutidine hydrochloride (IT-066), a novel H2-receptor antagonist, (0.3 mg/kg, s.c.) inhibited the formation of ulcer and reversed the inhibition of mucin sulfation by the CSI-treatment, whereas atropine sulfate, a muscarinic receptor antagonist, (1.0 mg/kg, s.c.) did not inhibit the development of ulcer nor decrease in the mucin sulfation at 6 hr after the CSI-treatment. IT-066 inhibited the total acid output (T.A.O.) due to the reduction of the acidity in the gastric juice, whereas atropine inhibited the T.A.O. due to that of the volume. These results indicated that a different mode of action between IT-066 and atropine on gastric acid secretion influences their actions in the incorporation of [35S]sulfate and the formation of ulcer in the CSI-treated rat. Therefore, it is considered that the reduction of biosynthesis of gastric sulfated mucin following acid hypersecretion may be responsible for the formation of gastric ulcer.

Effect of a novel 5-hydroxytryptamine3 (5-HT3) receptor antagonist, GK-128, on 5-HT3 receptors mediating contractions and relaxations in guinea-pig distal colon

1. We investigated 5-hydroxytryptamine3 (5-HT3) receptor-mediating contractions and relaxations in the guinea-pig isolated distal colon using various 5-HT3 receptor agonists and antagonists, including GK-128 (2-[(2-methylimidazol-1-yl) methyl] benzo[f] thiochromen-1-one monohydrochloride hemihydrate). 2. Selective 5-HT3 receptor agonists, 2-methyl-5-HT and m-chlorophenylbiguanide, produced spantide-insensitive contraction and atropine-insensitive contraction and the relaxation. These agonists showed a small, but significant, difference of potency between contraction and relaxation. 3. GK-128 competitively blocked both 2-methyl-5-HT- and m-chlorophenylbiguanide-induced responses with similar potency. The affinities of GK-128 for spantide-insensitive contraction and atropine-insensitive contraction were ten-fold higher than for relaxation. 4. Other selective 5-HT3 receptor antagonists, azasetron and tropisetron, also exhibited higher affinity in contraction than in relaxation, but the extent of their affinity differences was smaller than that observed in GK-128. In contrast, granisetron, ramosetron and ondansetron exhibited no significant differences in their affinity values among the three responses. 5. These results suggest that the 5-HT3 receptors which mediate contraction and relaxation in the guinea-pig distal colon may not be the same, and that GK-128 is a 5-HT3 receptor antagonist with a stronger potency for contraction.