Preliminary study on a novel quadruple eradication therapy with a mucoprotective drug, sofalcone, for Helicobacter pylori infection

To assess the effects of the mucoprotective drug sofalcone, which has direct and indirect effects on Helicobacter pylori in vitro, the eradication rate, adverse effects, and the quality of healing peptic ulcers were evaluated. Each study patient was given 500 mg t.i.d. amoxicillin and 200 mg t.i.d. clarithromycin. In addition, three different treatment regimens were compared: a standard dose (20 mg q.d.) of the proton pump inhibitor omeprazole (OAC), a double dose (20 mg b.i.d.) of omeprazole (Ox2AC), and a standard dose of omeprazole and a standard dose (100 mg t.i.d.) of sofalcone (OACS). Thirty-one H. pylori-positive patients were treated with OAC, 37 with Ox2AC, and 41 with OACS therapy. With an intention-to-treat analysis, the eradication rates were 74.2% for OAC, 86.2% for Ox2AC, and 85.0% for OACS therapy. The incidence of side effects was 9.6% for patients given OAC therapy, 86.5% for Ox2AC, and only 7.5% for OACS-treated patients, which was significantly lower than the incidence in the Ox2AC group. High-quality peptic ulcer scars were observed after eradication therapy which included solfacone. Although it is necessary to conduct a randomized double-blind study to obtain definitive conclusions, our results indicate that this novel quadruple eradication therapy with solfacone is an efficacious regimen with a high eradication rate and positive effects on ulcer healing, combined with a low incidence of adverse events.

Recombinant rat fibroblast growth factor-16: structure and biological activity

Fibroblast growth factor-16 (FGF-16) is the most recent member of the FGF family to be cloned. Since the biologic activity of rat FGF-16 (rFGF-16) was unknown, and this protein has no apparent signal sequence, we transformed its entire cDNA into Escherichia coli for high-level expression and further characterization of this novel protein. An attempt was made to purify the expressed protein from the supernatant of mechanically lysed cells using sequential cation-exchange chromatography. This resulted in a gradual loss of the protein as precipitate throughout the purification process. In addition to precipitation during purification, sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the partially purified materials showed a cluster of protein bands around 20k to 29k. Sequence analysis of the major bands indicated that two N-terminal truncations had occurred, during E. coli fermentation, purification, or both. The largest truncation resulted in the removal of the 34 N-terminal amino acids, including the initiation codon methionine. We cloned d34 rFGF-16, expressed the gene in E. coli, and developed a purification process for this form. Even with this truncated form, precipitation was a problem. We were largely able to overcome this problem, however, by including EDTA throughout the purification process. We have characterized the structure of purified d34 rFGF-16 extensively using circular dichroism, Fourier transform infrared spectroscopy, and sedimentation velocity analysis. These studies revealed that the protein has a distinct tertiary structure, consists primarily of beta-strands, has a weak tendency to self-associate, and is fairly extended. We then performed biologic assays which showed that d34 rFGF-16 induces oligodendrocyte proliferation in vitro, and induces hepatocellular proliferation and increased liver weight in vivo. In summary, FGF-16, a novel FGF family member, has both unique structural and biological properties.

Prostaglandins in the stomach: an update

Prostaglandins (PGs) are responsible for regulation of various physiologic activities in many tissues and organs, including the stomach. Recent studies have shown new crucial roles of PGs in the stomach. Activation of inflammatory cytokines and neutrophils may cause acute gastric mucosal lesions and recurrence of ulcers, which are induced by noxious stimuli such as nonsteroidal antiinflammatory drugs (NSAIDs), stress and Helicobacter pylori (H. pylori). These phenomena are PG-dependent because exogenous PGs reverse them. PG deficiency and H. pylori may worsen the quality of ulcer healing in terms of inflammatory responses, which are related to future ulcer recurrence. Neutrophils, monocytes/macrophages, and adhesion molecules are involved in the mechanism of recurrence caused by inflammatory cytokines. PGs accelerate ulcer healing, possibly via angiogenesis, epithelial cell proliferation, production of growth factors such as hepatocyte growth factor and transforming growth factor beta, reconstruction of extracellular matrices, and suppression of inflammatory cell infiltration, in addition to gastroprotective mechanisms. The PG synthase cyclooxygenase (COX) has two forms, COX-1 and COX-2. COX-2, but not COX-1, contributes to ulcer healing. Moreover, recent studies suggest the involvement of COX-2 in development of gastric and colon carcinoma. This may be linked to the chemopreventive effect of NSAIDs.

A case of diabetic muscle infarction in Japan

Diabetic muscle infarction (DMI) is a rare complication of diabetes mellitus. We report the first recorded case in Japan. A 45-year-old Japanese woman presented with severe pain in the left antero-medial thigh. She had a 14-year history of Type 2 diabetes mellitus (DM). She had first noticed pain in her left thigh after a walk 2 weeks prior to presentation. The pain worsened progressively. She noticed a firm mass in her left thigh. T2-weighted magnetic resonance imaging (MRI) demonstrated a high-intensity signal in the muscle bulk of the anterior component of the left thigh. A needle biopsy of the mass showed necrosis. She was treated with bedrest and an antiplatelet agent. The mass disappeared 8 weeks after admission. DMI is a rare complication of poorly controlled diabetes mellitus. Twenty-seven cases with DMI have been reported in the English literature but we believe this is the first Japanese case with DMI.

Phytoalexins from hairy roots of Hyoscyamus albus treated with methyl jasmonate

The treatment of hairy roots of Hyoscyamus albus with copper sulfate (Cu2+) and methyl jasmonate (JAMe) produced several phytoalexins having the vetispyrane skeleton. Lubimin and solavetivone were isolated after treatment with Cu2+. Seven sesquiterpenoid phytoalexins were isolated from the culture medium after treatment with JAMe, including lubimin, solavetivone, 3-hydroxysolavetivone and four new compounds (1-4). Structures of the new compounds were elucidated to be (3R,4S,5R,7S,9R)-3-hydroxy-9-tigloyloxysolavetivone (1), (3R,4S,5R,7S,9R)-3-hydroxy-9-(3-methylbutenoyloxy)-solavetivone (2), (3R,4S,5R,7S,9R)-3-hydroxy-9-isobutanoyloxysolavetivone (3); and (3R,4S,5R,7S,9R)-3,9-dihydroxysolavetivone (4). The induction pattern of phytoalexins in hairy roots treated with JAMe was different in those treated with Cu2+, and co-treatment with JAMe and Cu2+ gave only solavetivone.

Interactions between NFkappaB and its inhibitor ikappaB: biophysical characterization of a NFkappaB/ikappaB-alpha complex

The N-terminal domain (1-318 amino acids) of mouse NFkappaB (p65) has been purified to homogeneity from the soluble fraction of Escherichia coli cells expressing this protein. Its complex with a full-length ikappaB-alpha (MAD3, 1-317 amino acids) molecule was generated by binding the E. coli-derived ikappaB-alpha to the purified NFkappaB and purifying the complex by sequential chromatography. The stoichiometry of NFkappaB to ikappaB in the complex was determined to be 2 to 1 by light scattering and SDS-polyacrylamide gel electrophoresis. The secondary structure of the NFkappaB (p65) determined by Fourier-transform infrared (FTIR) spectroscopy is in good agreement with that of the p50 in the crystal structure of the p50/DNA complex, indicating that no significant structural change in NFkappaB occurs upon binding of DNA. The FTIR spectrum of the NFkappaB/ikappaB complex indicates that its secondary structure is composed of 17% alpha-helix, 39% beta-strand, 18% irregular structures, and 26% beta-turns and loops. By comparing these data to the FTIR data for NFkappaB alone, it is concluded that the ikappaB (MAD3) in the complex contains 35% alpha-helix, 27% beta-strand, 22% irregular structures, and 16% beta-turns and loops. Circular dichroism (CD) analysis of a shorter form of ikappaB (pp40) indicates that it contains at least 20% alpha-helix and that the ikappaB subunit accounts for nearly all of the alpha-helix present in the NFkappaB/ikappaB complex, consistent with the FTIR results. The stabilities of NFkappaB, ikappaB, and their complex against heat-induced denaturation were investigated by following changes in CD signal. The results indicate that the thermal stability of ikappaB is enhanced upon the formation of the NFkappaB/ikappaB complex.

Human leptin receptor. Determination of disulfide structure and N-glycosylation sites of the extracellular domain

The leptin receptor (OB-R) is a member of the class I cytokine receptor family and mediates the weight regulatory effects of its ligand through interaction with cytoplasmic kinases. The extracellular domain of this receptor is comprised of two immunoglobulin-like and cytokine-receptor homology domains each and type III fibronectin domains. The extracellular domain of human leptin receptor was expressed in and purified from Chinese hamster ovary cells and was found to contain extensive N-glycosylation (approximately 36% of the total protein). The purified protein had a molecular weight of approximately 145,000 and exhibited ligand binding ability as evidenced by formation of ligand-receptor complex, followed by chemical cross-linking. The determined disulfide motif of the soluble leptin receptor contained several distinct cystine knots as well as 10 free cysteines. The N-glycosylation analysis revealed that Asn624 of the WSXWS motif (residues 622-626) within the C-terminal cytokine receptor homology domain was glycosylated, indicating that this region is solvent-exposed. On the other hand, the N-terminal WSXWS motif was not glycosylated.

Regulation of matrix metalloproteinase-9 and inhibition of tumor invasion by the membrane-anchored glycoprotein RECK

A human fibroblast cDNA expression library was screened for cDNA clones giving rise to flat colonies when transfected into v-Ki-ras-transformed NIH 3T3 cells. One such gene, RECK, encodes a membrane-anchored glycoprotein of about 110 kDa with multiple epidermal growth factor-like repeats and serine-protease inhibitor-like domains. While RECK mRNA is expressed in various human tissues and untransformed cells, it is undetectable in tumor-derived cell lines and oncogenically transformed cells. Restored expression of RECK in malignant cells resulted in suppression of invasive activity with concomitant decrease in the secretion of matrix metalloproteinase-9 (MMP-9), a key enzyme involved in tumor invasion and metastasis. Moreover, purified RECK protein was found to bind to, and inhibit the proteolytic activity of, MMP-9. Thus, RECK may link oncogenic signals to tumor invasion and metastasis.

Coexpression of G-CSF with an unglycosylated G-CSF receptor mutant results in secretion of a stable complex

Previously, we have shown that the entire extracellular domain of the granulocyte-colony stimulating factor receptor (sG-CSFr) produced in Chinese hamster ovary (CHO) cells forms a stable complex with its ligand G-CSF, at a stoichiometry of 2:2. A truncated receptor molecule consisting of the cytokine receptor homology domain and N-terminus Ig-like domain (Ig CRH) behaves quite similarly. Both of these forms of the receptor are highly glycosylated. To address the importance of glycosylation toward receptor activity and stability, and possibly obtain nonglycosylated receptor for crystallization, mutations were made to replace four Asn residues which are N-glycosylated in the truncated receptor. Virtually no receptor was recovered from conditioned media of CHO cells transfected with this mutant construct, although a high-level of mRNA coding for receptor was detected; this mRNA was translated as determined by Western blots of cell lysates. These results indicate that the translated product is apparently not secreted from these cells. Cells transfected with mutant receptor cDNA were cotransfected with a cDNA construct expressing G-CSF in which the single O-glycosylation site was eliminated by mutation. Upon fermentation of the cotransfectants, we observed a large amount of receptor-ligand complex in the conditioned media. The purified unglycosylated complex appeared to be of the same binding stoichiometry and approximate binding affinity as that of complex formed by addition of purified ligand and unmutated receptor. These results show that while glycosylation of sG-CSFr is not necessary for ligand binding, it appears to be crucial in folding and export from the cell.

A plant-based cholera toxin B subunit-insulin fusion protein protects against the development of autoimmune diabetes

Oral administration of disease-specific autoantigens can prevent or delay the onset of autoimmune disease symptoms. We have generated transgenic potato plants that synthesize human insulin, a major insulin-dependent diabetes mellitus autoantigen, at levels up to 0.05% of total soluble protein. To direct delivery of plant-synthesized insulin to the gut-associated lymphoid tissues, insulin was linked to the C-terminus of the cholera toxin B subunit (CTB). Transgenic potato tubers produced 0.1% of total soluble protein as the pentameric CTB-insulin fusion, which retained GM1-ganglioside binding affinity and native antigenicity of both CTB and insulin. Nonobese diabetic mice fed transformed potato tuber tissues containing microgram amounts of the CTB-insulin fusion protein showed a substantial reduction in pancreatic islet inflammation (insulitis), and a delay in the progression of clinical diabetes. Feeding transgenic potato tissues producing insulin or CTB protein alone did not provide a significant reduction in insulitis or diabetic symptoms. The experimental results indicate that food plants are feasible production and delivery systems for immunotolerization against this T cell-mediated autoimmune disease.

FGF-18, a novel member of the fibroblast growth factor family, stimulates hepatic and intestinal proliferation

The fibroblast growth factors (FGFs) play key roles in controlling tissue growth, morphogenesis, and repair in animals. We have cloned a novel member of the FGF family, designated FGF-18, that is expressed primarily in the lungs and kidneys and at lower levels in the heart, testes, spleen, skeletal muscle, and brain. Sequence comparison indicates that FGF-18 is highly conserved between humans and mice and is most homologous to FGF-8 among the FGF family members. FGF-18 has a typical signal sequence and was glycosylated and secreted when it was transfected into 293-EBNA cells. Recombinant murine FGF-18 protein (rMuFGF-18) stimulated proliferation in the fibroblast cell line NIH 3T3 in vitro in a heparan sulfate-dependent manner. To examine its biological activity in vivo, rMuFGF-18 was injected into normal mice and ectopically overexpressed in transgenic mice by using a liver-specific promoter. Injection of rMuFGF-18 induced proliferation in a wide variety of tissues, including tissues of both epithelial and mesenchymal origin. The two tissues which appeared to be the primary targets of FGF-18 were the liver and small intestine, both of which exhibited histologic evidence of proliferation and showed significant gains in organ weight following 7 (sometimes 3) days of FGF-18 treatment. Transgenic mice that overexpressed FGF-18 in the liver also exhibited an increase in liver weight and hepatocellular proliferation. These results suggest that FGF-18 is a pleiotropic growth factor that stimulates proliferation in a number of tissues, most notably the liver and small intestine.

Protective effect of rebamipide against ammonia-induced gastric mucosal lesions

We investigated the protective effect of rebamipide against ammonia-induced gastric mucosal lesions. Participation of prostaglandin E2 and nitric oxide in the action of rebamipide was also examined. Rebamipide was administered intraperitoneally (10-100 mg/kg) to male Wistar/ST rats (150-325 g) fasted for 24 hr. Thirty minutes later, 1% NH4OH (1 ml) solution was given intragastrically. One hour later, the length of the mucosal lesions was measured (lesion index), and prostaglandin E2 (PGE2) was determined by radioimmunoassay. A 1% NH4OH solution caused gastric mucosal lesions with hemorrhagic necrosis and submucosal edema. PGE2 synthesis was not affected by NH4OH but was significantly increased by rebamipide. Rebamipide decreased the severity of NH4OH-induced gastric mucosal lesions in a dose-dependent manner. Pretreatment with indomethacin (5 mg/kg, subcutaneously) did not affect the protective effect of rebamipide; however, pretreatment with N(omega)-nitro-L-arginine (L-NNA, 1-10 mg/kg, intravenously), an inhibitor of nitric oxide synthase, attenuated the protective effect of rebamipide in a dose-dependent manner. Simultaneous administration of L-arginine (100 mg/kg) and L-NNA completely restored the protective effect of rebamipide, whereas D-arginine was inactive. These results suggest that nitric oxide contributes significantly to the protective effect of rebamipide against ammonia-induced gastric mucosal lesions.

Rebamipide: overview of its mechanisms of action and efficacy in mucosal protection and ulcer healing

Rebamipide, a gastroprotective drug, is a compound selected from over 500 amino acid analogs of 2(1H)-quinolinone tested for gastroprotective action and for efficacy to heal experimental gastric ulcers. This drug stimulates prostaglandin generation in gastric mucosa and improves not only the speed but also the quality of ulcer healing. In addition, it protects the gastric mucosa against acute injury caused by various noxious and ulcerogenic factors. Based on these experimental results, rebamipide had been subsequently tested in several clinical trials and approved in Japan for therapeutic use in patients with gastric ulcers and patients with acute gastritis. The main purpose of developing this type of drug was to improve the quality of ulcer healing, especially in that antisecretory drugs lack this advantage. In a preliminary clinical study, rebamipide improved the quality of gastric ulcer healing and reduced future ulcer recurrence. A number of basic research studies have been performed to clarify the mechanisms of rebamipide's action. These studies demonstrated unique properties of rebamipide and convincingly showed that it increases gastric mucus glycoprotein components, stimulates migration and proliferation of wounded epithelial cell monolayers, increases expression of epidermal growth factor and its receptor in normal and ulcerated gastric mucosa, and scavenges active oxygen radicals. The drug also attenuates the activity of neutrophils and the production of inflammatory cytokines stimulated by NSAIDs and/or H. pylori. Therefore, rebamipide can contribute to the management of patients who are taking NSAIDs or are infected with H. pylori. The inhibition of immunoinflammatory responses by rebamipide in H. pylori-infected patients may prevent development of gastritis, peptic ulcer disease, its recurrence, and possibly gastric cancer. Moreover, rebamipide may enhance eradication of H. pylori-infection using standard eradication therapy. Further studies are needed to clarify these possible advantages of rebamipide.

[The mechanisms of gastrointestinal mucosal injury and repair]

Peptic ulcer disease are usually accompanied by diffuse inflammation over the gastroduodenal mucosa in addition to severe local inflammation at the site of ulceration. It is well known that inflammatory cytokine are the main mediators of inflammation. Cytokines may also play a part in acute gastroduodenal mucosal lesions (AGML) caused by NSAID, H. pylori, and stress. Among cytokines most involved in AGML, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL) 1, IL-6, and IL-8 modulate chemotaxis, chemokinetics, and aggregation and release of lysosomal enzymes from neutrophils. Ulcer healing requires interaction of various cellular and connective tissue components. The stimulus for increased cell proliferation is most likely initiated by EGF and/or TGF-alpha which are mitogenic peptides for gastric epithelial cell at the initial stage in ulcer healing after ulcer induction. Transforming growth factor-beta (TGF-beta) also potentially involved in the ulcer healing process. During the chronic stage of ulceration, the growth of granulation tissue and generation of new microvessels by angiogenesis is stimulated by the fibroblast growth factors, platelet derived growth factor, TGF-beta, prostaglandins and/or IL-1 and TNF-alpha. The quality of mucosal restoration may be the most important factor in determining whether ulcers will recur. The proper restoration of the mucosal architecture requires balanced stimulation and interaction of both epithelial and connective tissue components, as well as, activation of growth factors which controls these components.

Expression and purification of cytokine receptor homology domain of human granulocyte-colony stimulating factor receptor in Escherichia coli

In an attempt to generate a stable non-glycosylated cytokine receptor homology (CRH) domain (Tyr97-Ala309) of human granulocyte-colony stimulating factor (G-CSF) receptor, two free cysteines in the CRH domain were converted to serine by site-directed mutagenesis. Taking advantage of the tight regulation for the expression of T7 RNA polymerase, the mutated CRH domain was successfully expressed in Escherichia coli (E. coli) with a pelB signal sequence at its NH2-terminus and with a His tag at its COOH-terminus. The processed and secreted CRH domain after solubilization and in vitro refolding retained G-CSF binding activity, and its yield (approximately 40 micrograms/30 ml culture) was more than 100-fold higher than that of the mouse CRH domain expressed by the MalE fusion system in E. coli.

Rebamipide treatment activates epidermal growth factor and its receptor expression in normal and ulcerated gastric mucosa in rats: one mechanism for its ulcer healing action?

Rebamipide (Mucosta) is a novel mucosal protective and ulcer-healing drug. Clinical and experimental data indicate that it accelerates ulcer healing and improves the quality of the scar. Since epidermal growth factor (EGF) and its receptor (EGF-R) play important roles in mucosal protection and ulcer healing, we studied whether rebamipide treatment affects expression of EGF and EGF-R in normal and ulcerated gastric mucosa in rats. Forty-eight male rats without or with gastric ulcers (induced by acetic acid) received intragastrically either placebo or rebamipide, 40 mg twice daily, for 14 days. Ulcer size was measured under a dissecting microscope; mucosal sections were stained with H&E or immunostained with specific antibodies against EGF and EGF-R. The distribution and intensity of fluorescence signal was quantified using a video image system. Rebamipide significantly accelerated ulcer healing, produced a significant increase in EGF and EGF-R expression in normal gastric mucosa (both P < 0.001), and increased expression of EGF and EGF-R in regenerating glands of the ulcer scar. Since EGF and its receptor are crucial for epithelial cell proliferation, re-epithelialization, and gland reconstruction, the above actions of rebamipide may provide a new mechanism for its ulcer healing action.

Ulcer recurrence: cytokines and inflammatory response-dependent process

H. pylori and nonsteroidal antiinflammatory drugs (NSAIDs) are important factors in the recurrence of peptic ulcer diseases. However, H. pylori-negative recurring ulcers can also be found in nonusers of NSAIDs. The aim of this paper is to review recent data pertaining to mechanisms of ulcer recurrence. Prostaglandin E2 generation is impaired in the tissues of the ulcer scar site and prostaglandin depletion induced by administration of indomethacin during the healing of experimental gastric ulcer predisposes to future ulcer recurrence. Therefore, the prostaglandin deficiency may impair the quality of ulcer healing and thus increase the likelihood of future ulcer recurrence. Persistent infiltration of polymorphonuclear cells is the most prominent finding in the gastric ulcer scar in rats treated with indomethacin. Concomitant administration of prostaglandin E1-analog with indomethacin attenuates inflammatory infiltration and reduces future ulcer recurrence. Therefore, the inflammatory responses at the ulcer scar site may be a key to the quality of ulcer healing. Recent clinical findings suggest a close relationship between the quality of ulcer healing, infiltration of neutrophils and mononuclear cells, and future ulcer recurrence. Gastroprotective drugs such as prostaglandin analogs and prostaglandin inducers improve the quality of ulcer healing and reduce future recurrence. Production of inflammatory cytokines is stimulated by ulcerogenic factors such as NSAIDs, stress, and H. pylori infection. Inflammatory cytokines such as interleukin-1beta and tumor necrosis factor-alpha cause recurrence of healed ulcer. Synthetic prostaglandin E2 inhibits recurrence as well as the production of the cytokines.

Effect of rebamipide on Helicobacter pylori infection in patients with peptic ulcer

This study was designed to assess whether the gastroprotective drug, rebamipide, aids in eradication of H. pylori. One hundred twenty patients, endoscopically diagnosed with gastric or duodenal ulcers and H. pylori infection, were randomly allocated to two treatment groups. Sixty patients received 40 mg of omeprazole twice a day, 1500 mg of amoxicillin three times a day, and 300 mg of rebamipide three times a day (group OAR); the other 60 patients received the same dosage of omeprazole and amoxicillin but no rebamipide for two weeks (group OA). All patients subsequently received an H2-receptor antagonist for six weeks. At the end of the treatment, endoscopy was performed to assess the status of the ulcers as well as the extent of H. pylori infection. In the intent-to-treat (73.3 vs 51.7%, P = 0.014) and per-protocol analyses (75.9 vs 55.3%, P = 0.021) the cure rates for H. pylori infection in group OAR were found to be significantly higher than those in group OA. Our findings suggest that rebamipide aids in curing H. pylori infection. This drug does not induce formation of resistant colonies and has few side effects.

[Gastrointestinal lesions in liver cirrhosis]

The gastrointestinal bleeding commonly observed in patients with liver cirrhosis is usually from esophageal and gastric varices, gastroduodenal ulcer, and congestive gastropathy. Portal hypertension is the major causative factor of pathogenesis of GI lesions. In the present review, we focus in gastric mucosal defense and Helicobacter pylori infection in liver cirrhosis. Gastric mucosal defense is reduced in liver cirrhosis, especially prostaglandins which play a role in the gastric mucosal defense decreased in the gastric mucosal of patients with liver cirrhosis and rat portal hypertension model. Although H. pylori is strongly associated with peptic ulcer disease and chronic gastritis, several studies showed no relationship between H. pylori infection and gastroduodenal ulcer or the infection and congestive gastropathy in liver cirrhosis. Reduced gastric mucosal defense may account for the pathogenesis of GI lesions in liver cirrhosis.

Rebamipide prevents recurrence of gastric ulcers without affecting Helicobacter pylori status

Rebamipide, a gastroprotective drug developed in Japan, accelerates ulcer healing and reduces recurrence of experimental gastric ulcers. We examined the effects of rebamipide, given during healing of human gastric ulcers infected with Helicobacter pylori, on the quality of ulcer healing and ulcer recurrence. Sixty H. pylori-positive patients with gastric ulcers were randomly allocated to three treatment groups: group O (N = 20) received 20 mg of omeprazole every day for eight weeks, group OR (N = 20) received the same dose of omeprazole and 300 mg of rebamipide three times a day for eight weeks, and group OA (N = 20) received the same dose of omeprazole for eight weeks and 1500 mg of amoxicillin three times a day for the first two weeks. After this treatment was completed no other medication was given. Endoscopic examinations were performed at the end of therapy (for healing rate), one month later (for rate of H. pylori eradication) and every three months for follow-up (for ulcer recurrence rate). At the end of therapy, biopsy specimens were taken from the gastric ulcer scar and examined under the microscope for neutrophil and mononuclear cell infiltration. The ulcer healing rate of the three groups was almost the same; H. pylori in group OA was 65% and that of the other two groups was 0%. The number of patients with a flat ulcer scar pattern (good quality of ulcer healing) was increased and the neutrophil infiltration was significantly improved in groups OR and OA compared to group O. The ulcer recurrence rate was significantly lower in group OA and group OR than in group O. In conclusion, rebamipide is almost equipotent to amoxicillin plus omeprazole for the reduction of ulcer recurrence. The decreased recurrence rate by rebamipide may be due to improvement of the quality of ulcer healing, reflected as in the suppression of inflammatory cell infiltration in the scar, which results from either cure of H. pylori infection and/or treatment with a gastroprotective drug such as rebamipide.

Increased mRNA levels of transforming growth factor-beta1 and monocyte chemoattractant protein-1 in ulcer relapse caused by interleukin-1beta in rats

This study investigated the mRNA expression of transforming growth factor-beta1 (TGF-beta1) and monocyte chemoattractant protein-1 (MCP-1) in rat gastric tissues in which ulcers had relapsed due to interleukin-1beta (IL-1beta) administration. Rats with healed ulcers were administered IL-1beta (1 microg/kg) and killed after 0, 12, 24, or 48 hr. Both TGF-beta1 and MCP-1 mRNA levels were increased in the scarred gastric tissues at 24 hr (fourfold), when ulcers had not relapsed. Furthermore, the expression of these genes also increased in the ulcerated gastric tissues at 48 hr (fivefold), when 90% of healed ulcers had relapsed. On the other hand, the number of macrophages that had infiltrated the scarred gastric tissues at 24 hr was two times higher than that at 0 hr. At 48 hr, the number of macrophages that had infiltrated gastric tissues in which ulcers had relapsed was similar to that at 24 hr. Thus, TGF-beta1 and MCP-1 may be implicated in the macrophage infiltration, thereby leading to ulcer relapse due to IL-1beta.

Correlation between the 1.6 A crystal structure and mutational analysis of keratinocyte growth factor

A comprehensive deletion, mutational, and structural analysis of the native recombinant keratinocyte growth factor (KGF) polypeptide has resulted in the identification of the amino acids responsible for its biological activity. One of these KGF mutants (delta23KGF-R144Q) has biological activity comparable to the native protein, and its crystal structure was determined by the multiple isomorphous replacement plus anomalous scattering method (MIRAS). The structure of KGF reveals that it folds into a beta-trefoil motif similar to other members of fibroblast growth factor (FGF) family whose structures have been resolved. This fold consists of 12 anti-parallel beta-strands in which three pairs of the strands form a six-stranded beta-barrel structure and the other three pairs of beta-strands cap the barrel with hairpin triplets forming a triangular array. KGF has 10 well-defined beta strands, which form five double-stranded anti-parallel beta-sheets. A sixth poorly defined beta-strand pair is in the loop between residues 133 and 144, and is defined by only a single hydrogen bond between the two strands. The KGF mutant has 10 additional ordered amino terminus residues (24-33) compared to the other FGF structures, which are important for biological activity. Based on mutagenesis, thermal stability, and structural data we postulate that residues TRP125, THR126, and His127 predominantly confer receptor binding specificity to KGF. Additionally, residues GLN152, GLN138, and THR42 are implicated in heparin binding. The increased thermal stability of delta23KGF-R144Q can structurally be explained by the additional formation of hydrogen bonds between the GLN side chain and a main-chain carbonyl on an adjoining loop. The correlation of the structure and biochemistry of KGF provides a framework for a rational design of this potentially important human therapeutic.