Antiallergic effects of ZCR-2060: effect on allergic cutaneous reactions and rhinitis models in mice and rats

The antiallergic action of 2-[2-[4-(diphenylmethyl)-1-piperadinyl] ethoxy] benzoic acid maleate (ZCR-2060) was investigated on allergic cutaneous reactions and nasal vascular permeability in mice and rats. ZCR-2060 markedly inhibited immediate allergic cutaneous reactions, including passive cutaneous anaphylaxis (PCA) in rats and mice; histamine-, compound 48/80- and calcium ionophore A 23187-induced cutaneous reactions in rats; and biphasic skin reactions mediated by monoclonal IgE antibody and epicutaneous challenge with antigen in mice, but did not affect 5-hydroxytryptamine-induced cutaneous reaction in rats. The antigen-induced nasal vascular permeability increase in actively and passively sensitized rats and histamine-induced nasal vascular permeability increase in rats (allergic rhinitis model) were clearly inhibited in a dose-dependent fashion by ZCR-2060. Moreover, ZCR-2060 significantly inhibited antigen-induced anaphylactic histamine release from rat peritoneal mast cells and carrageenin-induced paw edema in rats. These results suggest that ZCR-2060 has antiallergic effects on allergic cutaneous reactions and experimental rhinitis, probably due to histamine H1-receptor blockage and the inhibition of histamine release.

Antiallergic effect of ZCR-2060: antihistaminic action

The antihistaminic effect of 2-[2-[4-(diphenylmethyl)-1-piperadinyl]ethoxy] benzoic acid maleate (ZCR-2060), a newly synthesized antiallergic agent, was investigated in both in vitro and in vivo studies. ZCR-2060 clearly antagonized histamine-induced contraction of isolated guinea pig ileum and trachea. In contrast, carbachol-, BaCl2- and 5-hydroxytryptamine-induced contractions of isolated guinea pig ileum were slightly inhibited by higher concentrations of ZCR-2060. 3H-Mepyramine specific binding to membranes from guinea pig lung and brain were markedly inhibited by ZCR-2060 in a concentration-dependent fashion. In the in vitro studies, the antihistaminic effect of ZCR-2060 was greater than those of cetirizine and terfenadine, but was less than that of ketotifen. In the in vivo studies, ZCR-2060 significantly inhibited the histamine-induced cutaneous reaction in rats, when administered orally 1 hr before the histamine injection. Moreover, ZCR-2060 has a long-lasting antihistaminic effect. In the in vivo studies, the antihistaminic effect of ZCR-2060 was found to be greater than that of cetirizine and terfenadine, and it was the same as that of ketotifen. Thiopental-induced sleep and spontaneous ambulatory activity in mice, however, were unaffected by ZCR-2060 at higher doses. These results indicate that ZCR-2060 has a potent, selective and long acting histamine H1-receptor antagonistic action without causing any unwanted CNS side effect.

Transcriptional and Posttranscriptional Regulation of Nitrogen-Responding Expression of Phosphoenolpyruvate Carboxylase Gene in Maize

To study the regulation of gene expression for enzymes in the C4 photosynthetic pathway of maize (Zea mays L.) in response to changing N status in developing photosynthetic cells, we have studied in vitro transcription of the phosphoenolpyruvate carboxylase (PEPC) gene in leaf nuclei isolated from plants during recovery from N starvation. The induction was specific for the C4-type PEPC gene (C4Ppc1), and its transcription was N dependent and increased markedly by supply of an N source, but there was a discrepancy between the steady-state levels of mRNA and the stimulation of in vitro transcription. The results suggest that the N-inducible expression of C4Ppc1 is regulated both transcriptionally and posttranscriptionally by N availability. The in vitro transcription rate of C4Ppc1 was greatly stimulated by incubating detached leaves with zeatin alone, whereas the rate remained essentially unchanged by incubating with an exogenous N source alone. The results, taken together, imply that cytokinins up-regulate the transcription of C4Ppc1 in response to N status, whereas glutamine and/or its metabolite(s) up-regulate the level of the transcript. The transcription was totally inhibited by cycloheximide, indicating that the cytokinin-dependent transcription of C4Ppc1 requires the synthesis of protein.

[Two cases of bladder cancer in patients with chronic renal failure]

We report here two cases of bladder cancer in patients with chronic renal failure who had been treated with hemodialysis. Case 1: A 58-year-old male on hemodialysis for 3 years visited with a complaint of gross hematuria. Transurethral resection of the bladder tumor (TUR-Bt) was performed and histopathological examination showed grade 1, stage pTa transitional cell carcinoma (TCC). The patient was followed for 4 years postoperatively without recurrence. Case 2: A 64-year-old male with hemodialysis for 1 week was referred to our department with a gross hematuria. TUR-Bt was conducted and histopathological findings showed grade 2, stage pT1b TCC. In April, 1992, he revisited our hospital with bladder tamponade due to massive hematuria, and TUR-Bt was performed. Histopathologically, the tumors were grade 2, stage pT2 TCC. He was followed for 1 year without recurrence.

Sec-Y protein is localized in both the cytoplasmic and thylakoid membranes in the cyanobacterium Synechococcus PCC7942

Members of the SecY protein family mediate protein export in bacterial cells. Southern analyses showed that secY is likely a single copy gene in the cyanobacterium Synechococcus PCC7942. Then the subcellular location of the cyanobacterial SecY protein was determined; i) antiserum raised against a fusion protein between the SecY fragment and maltose binding protein were used for immunoblotting of the membrane fractions, and ii) a modified SecY protein carrying the c-Myc peptide tag was expressed in the cyanobacterial cells, and the subcellular distribution of the SecY-c-Myc fusion protein was analyzed with the anti-c-Myc antibodies. The obtained results suggest that the SecY protein is localized in the thylakoid membrane as well as the cytoplasmic membrane; the SecY protein probably mediates protein translocation across both the cytoplasmic and thylakoid membranes in Synechococcus PCC7942.

[Clinical analysis in 2266 cases of transurethral resection of the prostate]

During the past 20 years from August 1971 to July 1991, 3215 cases of transurethral resection were performed at Kitasato University Hospital, and consisted of 2008 benign prostatic hyperplasias, 692 bladder tumors, 258 prostate cancers, 167 bladder neck contractures, 38 urethral strictures, 20 chronic prostatities and 32 various urologic diseases. On 2266 transurethral resections of the prostate including 2008 benign prostatic hyperplasias, and 258 prostate cancers analysis was conducted. Patient age ranged from 44 to 97 (mean, 70.1). Resected tissue varied from 1 to 177 (mean, 26.9) grams. The time required for resection was from 9 to 245 (mean, 73.0) minutes. The volume of irrigation fluid was from 4 to 92 (mean, 25.0) liters. The duration of catheter placement after operation was 3 to 44 (mean, 4.1) days and hospitalization, 10 to 81 (mean, 12.1) days. The number of complications and blood transfusions were 308 (13.6%) and 381 (16.8%) respectively. Resected amount of tissue, volume of irrigation fluid, duration of catheter placement and frequency of complication in the benign prostatic hyperplasia group exceeded those in prostate cancer group. The length of hospitalization and blood transfusion rates were higher in the prostate cancer group. The rate or frequency of each item increased with the operating time and amount of resected tissue. Today, 60 minutes of operating time as a limiting factor of transurethral resection is not considered a important factor. Based on the results of the 2266 TURP cases, an attempt will be made to establish safer methods of treatment.

[Pre-operative, operative and postoperative complications in 2266 cases of transurethral resection of the prostate]

Pre-operative and operative complications in 2266 patients having undergone transurethral resection of prostate (TURP) for the past 20 years at Kitasato University Hospital were analyzed. They consisted of 2008 benign prostatic hyperplasia and 258 prostate cancer patients. Seven hundred and fifty four patients showed some of physical disorders prior to TUR:hypertension in 147 cases, diabetes mallitus in 87, ischemic heart disease in 46, chronic obstructive lung disease in 41 and others. Operative and postoperative complications of TURP were seen in 308 cases (13.6%). Perforation of the prostatic capsule was seen in 100 cases (4.4%) and bladder perforation into intraperitoneal cavity in 6 cases (0.3%). Transurethral fulgulation for postoperative hemorrhage was conducted on 79 cases (3.5%). Hyponatremia lower than 130 mEq/L was noted in 14 cases (0.6%). Severe urinary tract infection leading to bacteremia was observed in 9 cases (0.4%). Postoperative epididymitis was evident in 20 cases (0.8%). There was postoperative urinary incontinence in 19 cases, 3 of which was treated with Teflon-paste injection successfully. One patient had to undergo AMS-800 artificial sphincter implantation. The number of postoperative urethral stricture patients requiring urethral dilatation or internal urethrotomy was 12 (0.5%) and postoperative bladder neck contracture was seen in 20 cases (0.9%). One patient (0.04%) who developed DIC after profuse postoperative hemorrhage died on the 37th postoperative day. The efficiency of TURP depends not so much on the skill of cutting as on the speed and accuracy of orientation and haemostasis. The quick recognition of anatomical landmarks will assure effective and safe resection.

[Speech disturbance in acute stage of putaminal hemorrhage]

Speech disturbance was evaluated in the acute stage of 34 patients with left putaminal hemorrhage. Twenty-two patients were surgically treated and 12 were medically treated. Word cognition, naming, and obedience to verbal command were evaluated according to the STLA severity grade, and speech disturbance in the acute stage was classified as 10 severe cases, 13 moderate cases and 9 mild cases. Severity of speech disturbance was correlated to severity of hemiparesis, volume of hematoma and extension of hematoma. The cases with hematomas extending to the corona radiata showed severe speech disturbance. At the time of re-evaluation about one month after the initial evaluation, 13 cases showed improvement of the disturbance to some extent, but 19 cases showed no improvement. The improvement was related to severity of initial speech disturbance, type of hematoma and volume of hematoma. The hematomas whose volumes were over 30ml were related to poor recovery. However, the cases with hematomas extending to the posterior part of the corona radiata showed poor improvement even though the volume was less than 30 ml. In conclusion, these clinical factors, especially the degree of hematoma extension shown on CT scan, are useful for diagnosis and evaluation of speech disturbance in putaminal hematoma.

Identification and characterization of a gene cluster involved in nitrate transport in the cyanobacterium Synechococcus sp. PCC7942

The nrtA gene, which has been proposed to be involved in nitrate transport of Synechococcus sp. PCC7942 (Anacystis nidulans R2), was mapped at 3.9 kb upstream of the nitrate reductase gene, narB. Three closely linked genes (designated nrtB, nrtC, and nrtD), which encode proteins of 279, 659, and 274 amino acids, respectively, were found between the nrtA and narB genes. NrtB is a hydrophobic protein having structural similarity to the integral membrane components of bacterial transport systems that are dependent on periplasmic substrate-binding proteins. The N-terminal portion of NrtC (amino acid residues 1-254) and NrtD are 58% identical to each other in their amino acid sequences, and resemble the ATP-binding components of binding protein-dependent transport systems. The C-terminal portion of NrtC is 30% identical to NrtA. Mutants constructed by interrupting each of nrtB and nrtC were unable to grow on nitrate, and the nrtD mutant required high concentration of nitrate for growth. The rate of nitrate-dependent O2 evolution (photosynthetic O2 evolution coupled to nitrate reduction) in wild-type cells measured in the presence of L-methionine D,L-sulfoximine and glycolaldehyde showed a dual-phase relationship with nitrate concentration. It followed saturation kinetics up to 10 mM nitrate (the concentration required for half-saturation = 1 microM), and the reaction rate then increased above the saturation level of the first phase as the nitrate concentration increased. The high-affinity phase of nitrate-dependent O2 evolution was absent in the nrtD mutant. The results suggest that there are two independent mechanisms of nitrate uptake and that the nrtB-nrtC-nrtD cluster encodes a high-affinity nitrate transport system.

Cloning and characterization of the secY gene from the cyanobacterium Synechococcus PCC7942

The secY gene product is an essential component of the Escherichia coli cytoplasmic membrane, which mediates the protein translocation across the membrane. We found a gene homologous to secY in the genome of the cyanobacterium Synechococcus PCC7942. The deduced amino acid sequence, 439 amino acids long, shows 43% homology with that of the E. coli secY. The hydrophobic profile suggests that the Synechococcus SecY protein is an integral membrane protein containing ten membrane-spanning segments, which are closely related to the E. coli counterpart. The SecY protein may participate in the protein translocation across the cytoplasmic or thylakoid membrane in Synechococcus PCC7942.

Molecular cloning in Escherichia coli, expression, and nucleotide sequence of the gene for the ethylene-forming enzyme of Pseudomonas syringae pv. phaseolicola PK2

The gene for the ethylene-forming enzyme of Pseudomonas syringae pv. phaseolicola PK2 was found to be encoded by an indigenous plasmid, designated pPSP1. The gene for the ethylene-forming enzyme was cloned and expressed in Escherichia coli JM109. Nucleotide sequence analysis of the clone revealed an open reading frame that encodes 350 amino acids (mol. wt. 39,444). In a comparison with other proteins, the homology score for the entire amino-acid sequence of the ethylene-forming enzyme of Pseudomonas syringae versus ethylene-forming enzymes from plants and 2-oxoglutarate-dependent dioxygenases was low. However, functionally significant regions are conserved.

Effect of a new non-steroidal anti-inflammatory combination of a histamine H2 antagonist and indomethacin on gastroduodenal mucosal membrane in rat

The new non-steroidal anti-inflammatory drug (NSAID), N-(3-[3-(piperidinyl-methyl) phenoxy] propyl)-carbamoyl-methylthio]ethyl 1-(p-chlorobenzoyl) 5-methoxy-2-methyl-3-indolyl-acetate (CP 331, CAS 127966-70-5), a compound with a structure of an ester combining indomethacin (IM) and a histamine H2 antagonist, has been reported to have anti-inflammatory, analgesic and antipyretic effects. However, the influence of CP-331 on the gastroduodenal mucosa was not fully investigated. Therefore this study was undertaken to investigate the effect of CP-331 on the gastroduodenal mucosa membrane in rats. After single oral drug administration, the UD50 value (50% ulcerogenic dose) of CP-331 calculated from the incidence rate of gastric ulcer was higher than 1000 mg/kg; that for IM was 5.2 mg/kg. Moreover it was examined whether CP-331 had a preventive effect on NSAID-induced gastric damage. The results showed that the co-administration of CP-331 10-30 mg/kg prevented significantly the acute gastric mucosal injury caused by IM administration (20 mg/kg). CP-331 with anti-inflammatory activity does not cause gastric injury, moreover, because of its preventing and therapeutic effects on the damage to gastric mucous membrane induced by IM, CP-331 might be useful in the treatment of gastropathy caused by NSAID in clinic.

Oblique sagittal magnetic resonance imaging visualizing vascular compression of the trigeminal or facial nerve

An oblique sagittal magnetic resonance (MR) imaging method was developed to provide better visualization of vascular compression of nerves. The MR images of 12 patients with trigeminal neuralgia and 24 with hemifacial spasm were analyzed. The oblique sagittal views were obtained along the nerve identified by the axial view at an angle of 105 degrees between the line along the dorsal brain stem and the line along the margin of the pontomedullary junction (in patients with hemifacial spasm) or by the midsagittal view through the midpons (in patients with trigeminal neuralgia). The T1- and T2-weighted, proton-density, and/or gradient-echo MR images were evaluated to optimize imaging conditions. The oblique sagittal gradient-echo MR image most clearly visualized vascular compression of the nerves as high-intensity lines in six patients with trigeminal neuralgia, which was confirmed intraoperatively in four. Fifteen (75%) of 20 oblique sagittal gradient-echo MR images demonstrated vascular compression of the facial nerves in patients with hemifacial spasm; 12 of these were confirmed intraoperatively. The control study used 15 oblique sagittal gradient-echo MR images of nonaffected contralateral and normal sites. Four false-positive findings were found. Oblique sagittal gradient-echo MR images are a useful planning aid, allowing differential diagnosis prior to microvascular decompression in trigeminal neuralgia and hemifacial spasm.

Anti-inflammatory, analgesic, and antipyretic effects and gastrointestinal toxicity of the new anti-inflammatory drug N-(3-[3-(piperidinylmethyl)phenoxy]propyl)-carbamoylmethylthio ]ethyl 1-(p-chlorobenzoyl) 5-methoxy-2-methyl-3-indolylacetate

The anti-inflammatory, analgesic, and antipyretic effects and gastrointestinal toxicity of N-(3-[3-(piperidinylmethyl) phenoxy] propyl)- carbamoylmethylthio] ethyl 1-(p-chlorobenzoyl) 5-methoxy-2-methyl-3-indolylacetate (CP-331, CAS 127966-70-5), a new anti-inflammatory drug, were evaluated using indomethacin as a control. CP-331 exerted anti-inflammatory, analgesic and antipyretic effects on the models of carrageenin-induced paw edema, increased vascular permeability, ultraviolet light-induced erythema, granuloma proliferation, adjuvant arthritis, inflammatory pain, and yeast-induced fever. However, these effects were observed at a molar level similar to or higher than that of indomethacin. In addition, CP-331 influenced more markedly than indomethacin the delayed type hypersensitivity to sheep red blood cells. On the other hand, CP-331 did not damage the gastric mucosa even at a high dose of 1,000 mg/kg and also induced slighter damage to the intestinal mucosa than indomethacin. Thus, CP-331 exerted anti-inflammatory, analgesic, and antipyretic effects but without showing gastric toxicity, which is a common side effect of anti-inflammatory drugs. These results suggest the clinical applicability of this drug in the long-term therapy of inflammatory diseases such as rheumatoid arthritis.

Neural and infranuclear region changes in outer hair cells in acoustically exposed rabbits

Rabbits were exposed to 100 dB pure-tone sound at 2 kHz for 2 h. Electron microscopy was used to study the relationship between changes in the outer hair cells, afferent nerve endings and efferent nerve endings. There was no relationship found between the degree of changes produced in the afferent nerve endings and that the outer hair cells. However, there was a relationship demonstrable between the degree of changes seen in the efferent nerve endings and the infranuclear region of the outer hair cells. These findings show that acoustic trauma will damage most the infranuclear region of the outer hair cells, while efferent nerve endings are injured next and least affected are afferent nerve endings.

Leukemic pneumonitis as a poor prognostic factor in chronic myelomonocytic leukemia

We report the case of a 69-year-old man with chronic myelomonocytic leukemia (CMML) that was complicated by fatal respiratory failure. Bilateral pulmonary infiltrates were demonstrated by chest roentgenograms and worsened with an increase in the leukocyte count. Postmortem examination confirmed the presence of leukemic monocyte infiltration of the pulmonary interstitial spaces. In CMML with marked monocytosis, respiratory failure may be one of the important causes of death in addition to infection and bleeding.

Effects of successive doses of nizatidine, cimetidine and ranitidine on serum gastrin level and gastric acid secretion

Nizatidine (N-[2-[[[2-[(dimethylamino)methyl]- 4-thiazolyl]methyl]thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine , CAS 76963-41-2) is a new histamine H2-receptor antagonist which shows suppression of gastric acid secretion and antiulcer activity. In the present experiment, the effects of single s.c. administration of nizatidine, cimetidine and ranitidine on serum gastrin levels were studied in fasted rats. Nizatidine at 100 mg/kg increased serum gastrin level 3 h after administration, which however, returned to basal level 6 h after administration. Cimetidine and ranitidine at respective doses of 250 and 100 mg/kg markedly increased serum gastrin levels 3 and 6 h after administration. In a previous study, the suppressive effect of nizatidine on basal gastric acid secretion was 82.8% at a dose of 100 mg/kg s.c. in rat pylrus-ligated model. On the basis of these findings, changes in basal gastric acid secretion and serum gastrin level after withdrawal of nizatidine, cimetidine and ranitidine administered for 14 consecutive days were studied. One day after withdrawal, nizatidine at 100 mg/kg showed a tendency to increase the basal gastric acid secretion. However, 3 and 7 days after administration, almost no changes were obtained. Cimetidine at 250 mg/kg showed a tendency to increase the basal gastric acid secretion 7 days after withdrawal of the drug. Ranitidine at 100 mg/kg induced no changes in basal gastric acid secretion after withdrawal. No obvious influences of all drugs on serum gastrin level after withdrawals were obtained. These results indicate that consecutive administration of nizatidine may cause only a transient increase of gastric acid secretion but no hypergastrinaemia after its withdrawal.

[Organized chronic subdural hematoma; report of two cases]

Two cases of organized chronic subdural hematoma were presented. The first case had a one-year history of disorientation and right hemiparesis. CT scan revealed a low density area with linear high density in its medial margin, suggesting chronic subdural hematoma on the left frontal convexity. Surgery was performed expecting to remove the hematoma. There was, however, only a little fluid inside with thick membranous tissue. The second case, who has Crouzon disease, presented a one-year history of pseudobulbar palsy and tetraparesis after surgery for chronic subdural hematoma and hydrocephalus. The diagnosis of organized subdural hematoma was made at the time of reoperation which was performed expecting to remove the recurrent chronic subdural hematoma. Plain CT, done after admission to our hospital, showed homogeneous low density area remaining in the bilateral frontal convexity. Infusion scan revealed marked enhancement of the medial margin of the low density area. The lesion was demonstrated as a low intensity area by T1-weighted magnetic resonance images (MRI). Marked enhancement was noted around the low intensity area after the infusion of Gd-DTPA. Although it is very hard to make a diagnosis of organized chronic subdural hematoma using only the CT scan preoperatively, combination of the CT scan and MRI with Gd-DTPA enhancement seemed to be very useful for this purpose.

Effects of the new anti-ulcer drug nizatidine on prostaglandins in the rat gastric mucosa

The effects of nizatidine (N-[2-[[[2-[(dimethylamino)methyl]- 4-thiazolyl]methyl]thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine , CAS 76963-41-2), a new histamine H2-receptor antagonist, on the content of prostaglandins (PGs) in the rat gastric mucosa at doses that inhibit basal gastric acid secretion were compared with those of two other histamine H2-receptor antagonists, cimetidine and ranitidine. Nizatidine did not inhibit basal gastric acid secretion at a dose of 0.4 mg/kg but showed dose-dependent inhibition at doses of 10, 30, and 100 mg/kg. This drug had no effects on the content of PG in the gastric mucosa when subcutaneously administered at doses of 0.4, 10, 30 and 100 mg/kg once daily for 5 days. Cimetidine and ranitidine administered at doses that markedly inhibit basal gastric acid secretion (250 and 100 mg/kg/d, respectively) had no effects on the content of PG in the gastric mucosa. On the other hand, nizatidine, cimetidine, or ranitidine at concentrations of 1-100 mumols/l did not inhibit in vitro PGE2 synthesis using sheep seminal vesicle microsomes. These results suggest that nizatidine did not affect in vitro PGE2 synthesis and even doses that markedly inhibit gastric acid secretion had no effects on the content of PGs in the gastric mucosa.

Sequencing and Modification of the Gene Encoding the 42-Kilodalton Protein in the Cytoplasmic Membrane of Synechococcus PCC 7942

A 42-kilodalton cytoplasmic membrane protein is synthesized when high CO(2)-grown cells of Synechococcus PCC 7942 (Anacystis nidulans R2) are exposed to low CO(2). The structural gene for this protein (cmpA) has been cloned and sequenced and shown to encode a 450 amino acid polypeptide with a molecular mass of 49 kilodalton. A deletion mutant lacking the 42-kilodalton protein was obtained by transformation of Synechococcus PCC 7942 following in vitro mutagenesis of the cloned gene. There were no significant differences between the mutant and wild-type cells in their growth rates under either low or high CO(2) conditions. The activity of inorganic carbon (C(i)) transport in the mutant was as high as that in the wild-type strain. In both types of cells, CO(2) was the main species of C(i) transported and the activities of CO(2) and HCO(3) (-) transport increased when high CO(2)-grown cells were exposed to low CO(2). We conclude that the 42-kilodalton protein is not directly involved in the C(i)-accumulating mechanism of Synechococcus PCC 7942.

[Effects of the anti-ulcer agents on the amine contents and regulating enzyme activity of gastric mucosa during the healing process of acetic acid induced gastric ulcer in rats]

In order to elucidate the action of an H2 blocker (cimetidine) and gastric mucosal protection agents (sucralfate and sofalcone) on the relapse and recurrence of gastric ulcer, the effects of cimetidine, sucralfate and sofalcone on the contents of histamine and serotonin and histidine decarboxylase (HDC) activity in the gastric mucosa were examined in the ulcer region and the intact region at the 10th day after the operation to produce acetic acid-induced gastric ulcer in rats. The following results were obtained: 1) HDC activity in the gastric mucosa of rats treated with cimetidine (100 mg/kg twice daily) tended to increase in the intact region, and it was significantly increased in the ulcer region. 2) Increased HDC activity due to cimetidine treatment was observed at the 10th day after interruption of cimetidine administration. 3) The HDC activity in the gastric mucosa was not changed by the treatment with sucralfate (500 mg/kg/day) and sofalcone (200 mg/kg/day). The results suggest that the increased HDC activity in the gastric mucosa might participate in the relapse and recurrence of gastric ulcer after discontinuation of cimetidine administration.