Prevalence of Helicobacter pylori infection in gastric remnant after distal gastrectomy for primary gastric cancer

BACKGROUND

The development of a second primary cancer in the gastric remnant after gastrectomy for early gastric carcinoma is a problem, and eradication of Helicobacter pylori after the operation has been recommended. However, to date, practical indications for H. pylori eradication after gastric cancer surgery have not yet been reported.

METHODS

We examined H. pylori infection in the gastric remnant after distal gastrectomy for primary gastric cancer. One hundred and nine patients who had had a gastrectomy were studied. Endoscopic findings and results from the urease test, bacteriologic assessment, serological test, and histopathological examination were analyzed.

RESULTS

Seventy-one patients (65.1%) were judged to be positive for H. pylori infection. The prevalence of H. pylori infection was found to be significantly decreased in older patients, patients in whom the operation had been performed a long time before examination, patients with symptoms, and patients with severe reflux gastritis. On the other hand, histologically, chronic and acute gastritis correlated significantly with H. pylori infection. H. pylori prevalence was highest in mildly atrophic mucosa and decreased with more extensive atrophic changes of the mucosa.

CONCLUSIONS

The persistence of H. pylori-related active gastritis in the gastric remnant after gastric cancer surgery was suggested in younger patients with mild atrophic gastritis and without reflux gastritis. These patients may be the best candidates for H. pylori eradication therapy.

Determination of carbohydrate contents from excess light scattering

In the light scattering technique, glycosylation gives rise to excess light scattering for glycoproteins. Assuming additivity of refractive index and using an appropriate refractive index increment for carbohydrate, one can determine the degree of glycosylation from the excess light scattering. Here we have used size-exclusion chromatography in combination with online light scattering, UV absorbance, and refractive index. The results show that the technique accurately determines the carbohydrate content of recombinant stem cell factor.

The membrane-anchored MMP inhibitor RECK is a key regulator of extracellular matrix integrity and angiogenesis

Matrix metalloproteinases (MMPs) are essential for proper extracellular matrix remodeling. We previously found that a membrane-anchored glycoprotein, RECK, negatively regulates MMP-9 and inhibits tumor invasion and metastasis. Here we show that RECK regulates two other MMPs, MMP-2 and MT1-MMP, known to be involved in cancer progression, that mice lacking a functional RECK gene die around E10.5 with defects in collagen fibrils, the basal lamina, and vascular development, and that this phenotype is partially suppressed by MMP-2 null mutation. Also, vascular sprouting is dramatically suppressed in tumors derived from RECK-expressing fibrosarcoma cells grown in nude mice. These results support a role for RECK in the regulation of MMP-2 in vivo and implicate RECK downregulation in tumor angiogenesis.

Prevalence of Helicobacter pylori infection in gastric remnant after distal gastrectomy for primary gastric cancer

BACKGROUND

The development of a second primary cancer in the gastric remnant after gastrectomy for early gastric carcinoma is a problem, and eradication of Helicobacter pylori after the operation has been recommended. However, to date, practical indications for H. pylori eradication after gastric cancer surgery have not yet been reported.

METHODS

We examined H. pylori infection in the gastric remnant after distal gastrectomy for primary gastric cancer. One hundred and nine patients who had had a gastrectomy were studied. Endoscopic findings and results from the urease test, bacteriologic assessment, serological test, and histopathological examination were analyzed.

RESULTS

Seventy-one patients (65.1%) were judged to be positive for H. pylori infection. The prevalence of H. pylori infection was found to be significantly decreased in older patients, patients in whom the operation had been performed a long time before examination, patients with symptoms, and patients with severe reflux gastritis. On the other hand, histologically, chronic and acute gastritis correlated significantly with H. pylori infection. H. pylori prevalence was highest in mildly atrophic mucosa and decreased with more extensive atrophic changes of the mucosa.

CONCLUSIONS

The persistence of H. pylori-related active gastritis in the gastric remnant after gastric cancer surgery was suggested in younger patients with mild atrophic gastritis and without reflux gastritis. These patients may be the best candidates for H. pylori eradication therapy.

Intranasal immunization with recombinant Ascaris suum 14-kilodalton antigen coupled with cholera toxin B subunit induces protective immunity to A. suum infection in mice

Animals can be rendered immune to Ascaris parasites by immunization with infectious-stage larvae. The specific parasite gene products that mediate protective responses in ascariasis are unknown. We have identified a cDNA encoding Ascaris suum 14-kDa antigen (As14) and evaluated the vaccinal effect of the Escherichia coli-expressed recombinant protein (rAs14). GenBank analysis showed that As14 has low similarity at the amino acid level to a Caenorhabditis elegans gene product and to antigens of the filarial nematodes but not to other known proteins. In addition, As14 homologues were found to be expressed in human and dog roundworms. In mice that received intranasal administration of rAs14 coupled with cholera toxin B subunit (rAs14-CTB), there was a 64% reduction of recovery of larvae compared with that in the nontreated group. The vaccinated mice showed a significant increase in the total serum immunoglobulin G (IgG) levels and the mucosal IgA responses. Elevation of the rAs14-specific IgE response was also seen. Measurement of the IgG subclasses showed a higher level of IgG1 and a lower level of IgG2a antibody response in the sera of the immunized mice, suggesting that protection was associated with a type II immune response. As14 is the first protective antigen against A. suum infection to be identified. Our immunization trial results in laboratory animals suggest the possibility of developing a mucosal vaccine for parasitic diseases caused by ascarid nematodes.

Mechanisms and roles of neutrophil infiltration in stress-induced gastric injury in rats

Water-immersion and restraint stress is associated with an increase in neutrophil infiltration into the gastric mucosa, but the mechanism responsible for this infiltration is unclear. We investigated the involvement of intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor-alpha (TNF-alpha) in neutrophil infiltration in stress-induced gastric injury in rats. Rats were administered neutralizing antibody against ICAM-1 or TNF-alpha and were subjected to induction of gastric injury by 6-hr water-immersion and restraint stress. To evaluate the relationship between gastric acid and neutrophil infiltration, some rats were given cimetidine before administration of stress. Neutralizing antibodies inhibited both the lesion formation and the increase in myeloperoxidase activity induced by stress. Expression of ICAM-1 on endothelial cells was increased by stress, accompanied by an increase of TNF-alpha-positive cells. Antibody against TNF-alpha inhibited this increase in ICAM-1 expression. Cimetidine almost completely inhibited gastric lesions, but did not affect myeloperoxidase activity. In conclusion, neutrophil infiltration in stress-induced gastric injury may be mediated by ICAM-1 and TNF-alpha, but not gastric acid, and may play crucial roles in the progression of gastric injury.

Effect of Helicobacter pylori culture supernatant on acute reflux esophagitis in a rat model

BACKGROUND/AIMS

Prevalence of Helicobacter pylori, especially cagA-positive strains is inversely related to gastroesophageal reflux disease. The aim of this study was to examine whether H. pylori culture supernatants affect acute esophagitis induced by acid or mixed reflux in rats.

METHODOLOGY

Three different H. pylori strains were used. Acute esophagitis was induced in 59 male Wistar rats by ligation of both the transitional regions between the forestomach and glandular portion, and the pylorus or the lower part of duodenum. After operation, the rats were either left untreated or treated with intragastric injection of either vehicle or H. pylori culture supernatants and were sacrificed 6 or 24 hours later. Esophagitis index, depth of esophageal lesions, esophageal epithelial degeneration, and infiltration of inflammatory cells were examined.

RESULTS

Gross esophageal erosions and ulcers were observed up to mid-esophagus in all animals. H. pylori culture supernatants did not affect esophageal mucosal injury and no histologically significant differences were found among rats.

CONCLUSIONS

H. pylori culture supernatants, regardless of cagA gene expression, did not affect acute esophagitis induced by acid or mixed reflux. This finding suggests that no powerful protective factors against reflux-induced mucosal injury were produced by H. pylori.

Removal of polyA tails from full-length cDNA libraries for high-efficiency sequencing

We have developed a method to overcome sequencing problems caused by the presence of homopolymer stretches, such as polyA/T, in cDNA libraries. PolyA tails are shortened by cleaving before cDNA cloning with type IIS restriction enzymes, such as GsuI, placed next to the oligo-dT used to prime the polyA tails of mRNAs. We constructed four rice Cap-Trapper-selected, full-length normalized cDNA libraries, of which the average residual polyA tail was 4 bases or shorter in most of the clones analyzed Because of the removal of homopolymeric stretches, libraries prepared with this method can be used for direct sequencing and transcriptional sequencing without the slippage observed for libraries prepared with currently available methods, thus improving sequencing accuracy, operations, and throughput.

Sorbicillinol, a key intermediate of bisorbicillinoid biosynthesis in Trichoderma sp. USF-2690

In the course of our screening program for free radical scavengers from Trichoderma sp. USF-2690, we found an unidentified metabolite (1) that appeared by the method used for HPLC analysis. Metabolite 1 gradually decreased with the production of bisorbicillinoids and was easily missed during the general isolation procedure. The LC-ESI-MS (negative) analysis for 1 gave m/z 247 as the (M-1)- ion peak. The hydrolysis of synthetic 6-O-acetylsorbicillinol (+/- -2) by 0.05 M KOH and acetylation of product 1 in an aqueous solution indicated that the structure of 1 was (6S)-4-(2,4-hexadienoyl)-3,6-dihydroxy-2,6-dimethyl-2,4-cyclohexadien-1-one, designated sorbicillinol, a quinol that has been postulated to be important in bisorbicillinoid biosynthesis.

PPAR-gamma ligands inhibit growth of human esophageal adenocarcinoma cells through induction of apoptosis, cell cycle arrest and reduction of ornithine decarboxylase activity

Peroxisome proliferator-activated receptor gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily, is involved in suppression of growth of several types of tumors such as liposarcoma, breast cancer, prostate cancer, and colon cancer, possibly through induction of cell cycle arrest and/or apoptosis. In this study, we demonstrated expression of PPAR-gamma mRNA and protein in human esophageal carcinoma cells. Expression of PPAR-gamma protein was higher in an adenocarcinoma cell line (TE-7 cells) than in a squamous cell carcinoma cell line (TE-1 cells). PPAR-gamma ligands such as 15-deoxy-Delta12,14-prostaglandin J2 and troglitazone significantly inhibited the growth of TE-7 cells but had less or no effect on growth of TE-1 cells. 15d-PGJ2 and troglitazone induced apoptosis in TE-7 cells but not in TE-1 cells. Troglitazone caused G1 cell cycle arrest and reduced ornithine decarboxylase activity (ODC) in TE-7 cells but not in TE-1 cells. Inhibition by PPAR-gamma ligands of growth of esophageal adenocarcinoma cells may thus be due to induction of apoptosis, G1 cell cycle arrest and reduction of ODC activity.

Possibility of false-positive detection for sporozoites in mosquitos (Diptera: Culicidae) by nested polymerase chain reaction using Plasmodium yoelii genomic DNA

Anopheles stephensi Liston and An. saperoi Bohart and Ingram infected with the rodent malaria parasite Plasmodium yoelii nigeriense. They were examined 12 and 19 days after blood feeding for sporozoites in head with anterior thorax (HT) and oocysts in abdomen with posterior thorax (AB) by light microscopy and by the nested polymerase chain reaction (nested PCR-based on the amplification of the sequences of the small subunit ribosomal RNA gene). The detection rate of parasite DNA by nested PCR in HT samples 12 days after blood feeding was similar to that by microscopic method. However, in HT samples 19 days after blood feeding, the rate by the PCR method was higher than that by the microscopic method. The incidence of sporozoites in salivary glands of infected mosquitos for 12 days after blood sucking was examined by the PCR method. Parasite DNA in HT of Aedes albopictus Skuse (a non vector for the rodent malaria) as well as An. stephensi and An. saperoi was detected for up to 4 days after feeding on mouse with the rodent malaria parasites. The results indicate that when the PCR method is used for detection of sporozoites of human malaria in mosquitos collected in the field, there are possibilities of including false-positive data for mosquitos that have just or recently fed on human blood infected with malaria (erythrocytic form).

Identification of larval-stage antigens of ascaris suum recognized with immune sera from pigs

Antigens were identified from the third-stage larvae (L3) and lung-stage larvae of Ascaris suum by two-dimensional immunoblot method with antisera obtained from pigs that received chemically abbreviated Ascaris suum larval infections. Forty-seven and 13 spots were recognized as antigens from the L3 and lung-stage larvae, respectively. Their apparent molecular weight ranged from 20 to 101 kDa and their isoelectric point from 3.6 to 8.0. The present study provides a framework for further molecular cloning of those antigens and consequently leads to the development of recombinant peptide vaccines against A. suum.

Kinetic and thermodynamic analysis of thermal unfolding of recombinant erythropoietin

Thermal stress was used to assess the stability of recombinant human erythropoietin (EPO) derived from Chinese hamster ovary cells. In 20 mm phosphate at pH 7.0, this protein had a highly reversible thermal unfolding as observed by far UV circular dichroism (CD) and native gel analysis, with no indication of protein aggregation. It had a relatively low melting temperature at 53 degrees C. Assuming a two-state transition, the observed reversibility permits thermodynamic analysis of the unfolding of EPO, which shows that the free energy of unfolding at 25 degrees C is only 6-7 kcal/mol. Upon heating to 79 degrees C over 30 min, however, this protein does undergo aggregation as assessed by native gel. In 20 mm phosphate and citrate at pH 7.0, the results are similar, i.e., EPO suffered a substantial aggregation, while it showed little aggregation in 20 mm Tris or histidine at pH 7.0 and 20 mm glycine at pH 6.3 under identical heat treatment.

Induction of thymic apoptosis by Shiga toxin from Escherichia coli O157:H7 in vivo and in vitro

It is not known how Shiga toxins (Stxs), which are major virulence factors of enterohemorrhagic Escherichia coli, can affect the host immune system. We investigated the effect of Stx2 on murine thymic cells in vivo and in vitro. After intraperitoneal administration of Stx2, the body weight of mice (BW) and the organ index of thymocytes (OIT) gradually decreased from day 1 to day 4. Apoptosis of thymocytes, assessed by TUNEL staining, and DNA fragmentation assay, was marked on day 3 and day 4. Decrease in BW and OIT due to Stx2 was antagonized by the simultaneous administration of murine anti-Stx2 IgG antibody with Stx2. In vitro administration of Stx2 also induced apoptosis of cultured thymocytes on day 3 and day 4 in a dose-dependent fashion. These results showed that Stx2 directly caused apoptosis of thymocytes in vivo and in vitro. Our findings imply that StA2 may be intimately related to pathogenesis of E. coli O157:H7 infection, by causing apoptosis of thymus.

Copper staining method for extracting biologically active proteins from native gels

An attempt was made to make protein bands visible on native gel using copper staining, since such a mild staining procedure would make the entire native gel electrophoresis process non-denaturing. Copper staining not only was able to detect various proteins on native gel with reasonable sensitivity, but also made extraction and recovery of active proteins possible from the gel using a gentle procedure.

Molecular cloning of groESL locus, and purification and characterization of chaperonins, GroEL and GroES, from Bacillus brevis

The groESL locus of a protein-hypersecreting bacterium, Bacillus brevis, was cloned by PCR using primers designed based on the DNA sequence of a B. subtilis homolog. GroEL protein was purified to apparent homogeneity and its ATPase activity was characterized: it hydrolyzed ATP, CTP, and TTP in this order of reaction rate, and its specific activity for ATP was 0.1 micromole/min/mg protein. Purified GroEL forms a tetradecamer. GroEL was estimated to contain 22% alpha-helix, 24% beta-sheet, and 19% turn structures, by CD measurement. GroES protein was also highly purified to examine its chaperonin activity. GroEL protected from thermal inactivation of and showed refolding-promoting activity for malate dehydrogenase, strictly depending on the presence of ATP and GroES.

Acid regulates inflammatory response in a rat model of induction of gastric ulcer recurrence by interleukin 1beta

BACKGROUND

In a previous study we showed that interleukin 1beta (IL-1beta) caused recurrence of gastric ulcers in rats, and that adhesion molecules (intercellular adhesion molecule 1 and leucocytic beta2 integrins) play a role in this recurrence. Although gastric acid plays an important role in many types of gastric injuries, including peptic ulcer recurrence, the mechanism(s) remains unclear.

AIMS

To examine the involvement of gastric acid in induction of ulcer recurrence by IL-1beta, and to investigate the role of gastric acid in inflammatory responses during ulcer recurrence.

METHODS

Rats with healed ulcers were used. Rats were given 1 microg/kg IL-1beta intraperitoneally. Another group of rats was given 20 mg/kg omeprazole for three days to inhibit acid secretion, and received IL-1beta 20 hours after the first administration of omeprazole. They were then given 0.15 N HCl or vehicle at 0, 12, 24, and 36 hours after IL-1beta treatment. Some rats were given acid alone at the same time points. Expression of adhesion molecules was examined immunohistochemically and concentrations of IL-1beta and tumour necrosis factor alpha (TNF-alpha) were measured by ELISA in scar tissue 24 hours after IL-1beta treatment.

RESULTS

IL-1beta increased expression of adhesion molecules and concentrations of IL-1beta and TNF-alpha in scar tissue by 24 hours after IL-1beta treatment, and nine of 11 healed ulcers had recurred by 48 hours. Omeprazole inhibited the effects of IL-1beta. HCl acid abolished the inhibitory effects of omeprazole. Acid alone affected neither expression of adhesion molecules nor cytokine concentrations, and did not cause recurrence.

CONCLUSIONS

Gastric acid is required for recurrence of gastric ulcers caused by IL-1beta, and gastric acid stimulates the inflammatory process in scarred mucosa during ulcer recurrence.

A case of isolated esophageal cyst in the posterior mediastinum

We report a rare case of posterior mediastinal esophageal cyst associated with pulmonary anomaly that had no connection with the proper esophagus, on either CT or MRI, and suggest including this entity in the differential diagnosis of posterior mediastinal masses.