Down-regulated expression of monocyte/macrophage major histocompatibility complex receptors in human and mouse monocytes by expression of their ligands.

Mouse monocyte/macrophage major histocompatibility complex (MHC) receptor 1 (MMR1; or MMR2) specific for H-2D(d) (or H-2K(d) ) molecules is expressed on monocytes from non-H-2D(d) (or non-H-2K(d) ), but not those from H-2D(d) (or H-2K(d) ), inbred mice. The MMR1 and/or MMR2 is essential for the rejection of H-2D(d) - and/or H-2K(d) -transgenic mouse skin onto C57BL/6 (H-2D(b) K(b) ) mice. Recently, we found that human leucocyte antigen (HLA)-B44 was the sole ligand of human MMR1 using microbeads that had been conjugated with 80 types of HLA class I molecules covering 94·2% (or 99·4%) and 92·4% (or 96·2%) of HLA-A and B molecules of Native Americans (or Japanese), respectively. In the present study, we also explored the ligand specificity of human MMR2 using microbeads. Microbeads coated with HLA-A32, HLA-B13 or HLA-B62 antigens bound specifically to human embryonic kidney (HEK)293T or EL-4 cells expressing human MMR2 and to the solubilized MMR2-green fluorescent protein (GFP) fusion protein; and MMR2(+) monocytes from a volunteer bound HLA-B62 molecules with a Kd of 8·7 × 10(-9) M, implying a three times down-regulation of MMR2 expression by the ligand expression. H-2K(d) (or H-2D(d) ) transgene into C57BL/6 mice down-regulated not only MMR2 (or MMR1) but also MMR1 (or MMR2) expression, leading to further down-regulation of MMR expression. In fact, monocytes from two (i.e. MMR1(+) /MMR2(+) and MMR1(-) /MMR2(-) ) volunteers bound seven to nine types of microbeads among 80, indicating ≤ 10 types of MMR expression on monocytes. The physiological role of constitutive MMRs on monocytes possibly towards allogeneic (e.g. fetal) cells in the blood appears to be distinct from that of inducible MMRs on macrophages toward allografts in tissue.

Effect of topical vancomycin powder on surgical site infection prevention in major orthopaedic surgery: a systematic review and meta-analysis of randomized controlled trials with trial sequential analysis.

BACKGROUND: Evidence has been mixed regarding the effect of topical vancomycin (VCM) powder in reducing surgical site infection (SSI). AIM: To clarify the effect of topical VCM powder for the prevention of SSI in major orthopaedic surgeries. METHODS: The MEDLINE, Embase, CENTRAL, ICTRP, and ClinicalTrials.gov databases were searched from their inception to September 25th, 2023. Randomized controlled trials comparing topical VCM powder and controls for the prevention of SSI in major orthopaedic surgeries were included. Two reviewers independently screened the title and abstract and extracted relevant data, followed by the assessment of the risk of bias and the certainty of the evidence. Main outcome measures were overall SSI, reoperation, and adverse events. Summary results were obtained using random-effects meta-analysis. Trial sequential analysis (TSA) was performed. FINDINGS: Eight randomized controlled trials yielded data on 4307 participants. VCM powder showed no difference in reducing overall SSI. The cumulative number of patients did not exceed the required information size of 19,233 in our TSA, and the Z-curves did not cross the trial sequential monitoring or futility boundary, suggesting an inconclusive result of the meta-analysis. No difference was found for reoperation. Among SSIs, VCM powder showed a statistically significant difference in reducing Gram-positive cocci SSI. However, the certainty of this evidence was very low. CONCLUSION: This systematic review and meta-analysis suggests inconclusive results regarding the effect of VCM powder in reducing SSI in major orthopaedic surgeries. Further trials using rigorous methodologies are required to elucidate the effect of this intervention.

A potent allele marker related to low bull conception rate in Japanese Black bulls.

Over the years, there has been considerable variation in the bull conception rate (BCR) of Japanese Black cattle; moreover, several Japanese Black bulls with a low BCR of ≤10% have been identified. However, the alleles responsible for the low BCR are not determined yet. Therefore, in this study, we aimed to identify single-nucleotide polymorphisms (SNPs) for predicting low BCR. To this end, the genome of Japanese Black bulls was comprehensively examined by a genome-wide association study with whole-exome sequencing (WES), and the effect of the identified marker regions on BCR was determined. The WES analysis of six sub-fertile bulls with a BCR of ≤10% and 73 normal bulls with a BCR of ≥40% identified a homozygous genotype for low BCR in Bos taurus autosome 5 in the region between 116.2 and 117.9 Mb. The g.116408653G > A SNP in this region had the most significant effect on the BCR (P-value = 1.0 × 10-23), and the GG (55.4 ± 11.2%) and AG (54.4 ± 9.4%) genotypes in the SNP had a higher phenotype than the AA (9.5 ± 6.1%) genotype for the BCR. The mixed model analysis revealed that g.116408653G > A was related to approximately 43% of the total genetic variance. In conclusion, the AA genotype of g.116408653G > A is a useful index for identifying sub-fertile Japanese Black bulls. Some positive and negative effects of SNP on the BCR were presumed to identify the causative mutations, which can help evaluate bull fertility.

Genome scanning for detecting adaptive genes along environmental gradients in the Japanese conifer, Cryptomeria japonica.

Local adaptation is important in evolutionary processes and speciation. We used multiple tests to identify several candidate genes that may be involved in local adaptation from 1026 loci in 14 natural populations of Cryptomeria japonica, the most economically important forestry tree in Japan. We also studied the relationships between genotypes and environmental variables to obtain information on the selective pressures acting on individual populations. Outlier loci were mapped onto a linkage map, and the positions of loci associated with specific environmental variables are considered. The outlier loci were not randomly distributed on the linkage map; linkage group 11 was identified as a genomic island of divergence. Three loci in this region were also associated with environmental variables such as mean annual temperature, daily maximum temperature, maximum snow depth, and so on. Outlier loci identified with high significance levels will be essential for conservation purposes and for future work on molecular breeding.

Recognition of endoscopic diagnosis in differentiated-type early gastric cancer by flexible spectral imaging color enhancement with indigo carmine.

BACKGROUND/AIMS: To evaluate the usefulness of flexible spectral imaging color enhancement with indigo carmine (I-FICE) in early gastric cancer (EGC) demarcation. METHODS: The study participants were 29 patients with differentiated-type EGC. The endoscope was fixed and images of the same area of EGC demarcations in each lesion were obtained using four different methods (WLE, flexible spectral imaging color enhancement (FICE), CE, and I-FICE). FICE mode at R 550 nm (Gain: 2), G 500 nm (Gain: 4), and B 470 nm (Gain: 4) was used. Four endoscopists ranked the images obtained by each method on the basis of the ease of recognition of demarcation using a 4-point system. We calculated the standard deviation of pixel values based on L*, a*, and b* color spaces in the demarcation region (Lab-SD score). RESULTS: The median ranking score for I-FICE images was significantly higher than that obtained from the other methods. Further, the average Lab-SD score was significantly higher for I-FICE images than for images obtained by the other methods. There was a good correlation between the ranking score and Lab-SD score. CONCLUSION: EGC demarcations were most easily recognized both subjectively and objectively using I-FICE image, followed by CE, FICE and WLE images.

Genetic analysis of semen production traits of Japanese Black and Holstein bulls: genome-wide marker-based estimation of genetic parameters and environmental effect trends.

The semen production traits of bulls from 2 major cattle breeds in Japan, Holstein and Japanese Black, were analyzed comprehensively using genome-wide markers. Weaker genetic correlations were observed between the 2 age groups (1 to 3 yr old and 4 to 6 yr old) regarding semen volume and sperm motility compared with those observed for sperm number and motility after freeze-thawing. The preselection of collected semen for freezing had a limited effect. Given the increasing importance of bull proofs at a young age because of genomic selection and the results from preliminary studies, we used a multiple-trait model that included motility after freeze-thawing with records collected at young ages. Based on variations in contemporary group effects, accounting for both seasonal and management factors, Holstein bulls may be more sensitive than Japanese Black bulls to seasonal environmental variations; however, the seasonal variations of contemporary group effects were smaller than those of overall contemporary group effects. The improvement of motilities, recorded immediately after collection and freeze-thawing, was observed in recent years; thus, good management and better freeze-thawing protocol may alleviate seasonal phenotypic differences. The detrimental effects of inbreeding were observed in all traits of both breeds; accordingly, the selection of candidate bulls with high inbreeding coefficients should be avoided per general recommendations. Semen production traits have never been considered for bull selection. However, negative genetic trends were observed. The magnitudes of the estimated h were comparable to those of other economically important traits. A single-step genomic BLUP will provide more accurate predictions of breeding values compared with BLUP; thus, marker genotype information is useful for estimating the genetic merits of bulls for semen production traits. The selection of these traits would improve sperm viability, a component related to breeding success, and alleviate negative genetic trends.

Transition of mouse de novo methyltransferases expression from Dnmt3b to Dnmt3a during neural progenitor cell development.

Dnmt3a and Dnmt3b, which are known as functional de novo methyltransferases, are responsible for creating genomic methylation patterns during mammalian development. Recently, we have shown that specific expression of Dnmt3b in epiblast, embryonic ectoderm, hematopoietic progenitor cells and spermatogonia cells is followed by Dnmt3a expression (Watanabe D, Suetake I, Tada T, Tajima S (2002) Stage- and cell-specific expression of Dnmt3a and Dnmt3b during embryogenesis. Mech Dev 118:187-190; Watanabe D, Suetake I, Tajima S, Hanaoka K (2004) Expression of Dnmt3b in mouse hematopoietic progenitor cells and spermatogonia at specific stages. Gene Expr Patterns 5:43-49). In this study, we analyzed the expression of mouse de novo methyltransferases during development of the nervous systems. In the embryonic olfactory epithelium (OE), Dnmt3b was specifically expressed in Mash1 positive globose basal cells (i.e. transiently amplifying neural progenitor cells), while Dnmt3a was expressed in immature olfactory receptor neurons. Dnmt3b-positive cells were rarely observed in the adult OE, but were increased in regenerating OE with intranasal ZnSO(4) administration. Dnmt3b was also detected in the E8.5 neural plate, E10.5 spinal cord and retina cells, while Dnmt3a was expressed in postmitotic young neurons. Furthermore, Dnmt3b was specifically expressed in ES cells, while Dnmt3a was transiently expressed during neural cell differentiation of ES cells. Dnmt3b is specifically expressed in progenitor cells during hematopoiesis, spermatogenesis and neurogenesis, suggesting an important role in the initial steps of progenitor cell differentiation. Dnmt3a is expressed in postmitotic young neurons following the Dnmt3b expression. Dnmt3a may be required for the establishment of tissue-specific methylation patterns of the genome. The coordinated expression of de novo methyltransferases from Dnmt3b to Dnmt3a suggests conserved mechanisms of de novo methylation of the genome and different functions for Dnmt3b and Dnmt3a during progenitor cell development.

Preoperative evaluation of the extrahepatic bile duct structure for laparoscopic cholecystectomy.

BACKGROUND: The incidence of aberrant bile duct injury associated with laparoscopic cholecystectomy (LC) has not yet been adequately examined. This study aimed to clarify the types of normal cystic ducts and the incidence of aberrant extrahepatic bile ducts, and to search for a method of avoiding injuries during LC. METHODS: Aberrant hepatic ducts were retrospectively categorized into five types according to the pattern of the cystic ducts and the accessory hepatic ducts by preoperative endoscopic retrograde cholangiography or multidetector three-dimensional computed tomography using drip infusion cholangiography. The aberrant bile ducts were classified as type A (merging at the right side of the common bile duct), type B (merging at the anterior side), or type C (merging at the posterior left side). RESULTS: The intrahepatic bile ducts and cystic duct were clearly shown for 1,044 of the 1,278 patients who underwent LC. Secondary branches of aberrant cystic ducts were observed in 37 cases (3.5%), and accessory hepatic ducts were observed in 30 cases (2.9%). A comparison of the difficulties encountered with LC for each type based on the merging patterns of cystic ducts showed that type C needed a much longer operation time for LC than the other types. CONCLUSIONS: A preoperative evaluation of the bile duct tract and the accessory hepatic duct before LC is important. Patients with a cystic duct merging normally into the posterior left side of the common hepatic duct (type C) experienced difficulty when undergoing LC. The authors have safely performed LC with the use of an endoscopic nasobiliary drainage tube in type D cases (cystic duct merging with the right hepatic duct), in type IV cases (cystic duct merging with an accessory hepatic duct).

Gender differences in postoperative pain after laparoscopic cholecystectomy.

BACKGROUND: Some evidence suggests that females have a lower pain threshold and a lower tolerance to painful stimuli. This study investigated gender differences in postoperative pain after laparoscopic cholecystectomy (LC) on the basis of visual analog pain scale (VAS) scores and the clinical course. METHODS: The 100 patients in this study (46 males and 54 females) underwent LC for cholecystolithiasis or gallbladder polyps without intraoperative complications. An 8-mm Penrose drain was retained for 42 h below the liver bed. All the patients were hospitalized for 4 days after LC, and the pain reported by patients, the time course of changes in the highest body temperature, the leukocyte count, and the C-reactive protein level were studied comparatively for the male and female patients. RESULTS: The VAS scores were significantly higher for the female patients than for the male patients at 24 h (62.7 +/- 24.6 vs 47.0 +/- 23.3; p = 0.0015) and at 48 h (39.2 +/- 24.3 vs 28.3 +/- 19.1; p = 0.0137) after LC. The female patients used analgesics more frequently and had significantly higher body temperatures than the male patients on day 1 (37.2 +/- 0.6 vs 36.9 +/- 0.4; p = 0.0037) and day 2 (36.9 +/- 0.6 vs 36.6 +/- 0.4; p = 0.0037) after surgery. CONCLUSIONS: Early postoperative pain after LC was more severe in female patients, and patients with high VAS scores tended to use analgesics more frequently.

Characterization of a human monoclonal antibody with broad reactivity to malignant tumor cells.

Lymphocytes from mediastinal lymph nodes of 9 patients with primary lung cancer were fused with murine myeloma cells (P3U1). One of the clones (4G12) was stable for secretion (10 micrograms/ml) of human IgM lambda for 24 months. The antigen detected by 4G12 was sensitive to both trypsin and periodic acid-Schiff treatment. It immunoprecipitated a glycoprotein with an Mr of 65,000 upon analysis in sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reduced conditions. Immunohistochemical staining demonstrated that 4G12 possessed a high reactivity to squamous cell carcinomas of the lung (29 of 29) and also reacted with other lung carcinomas [adenocarcinomas (14 of 20) and large cell carcinomas (3 of 8)] and with some nonpulmonary malignant tumors (15 of 56). However, it did not react with small cell carcinomas of the lung. No benign tumors (0 of 26) so far tested have been positive. 4G12 did not react with most of the normal tissues; an exception was that it was weakly reactive on the glandular cells of the trachea and bronchi and on the proximal tubular cells of the kidneys. Thus 4G12 showed a broad reactivity to malignant tumors (68% of lung carcinomas, 27% of nonpulmonary carcinomas, and 0% of benign tumors). The reactivity of 4G12 on tissues from squamous cell carcinomas of the lung indicated that the expression of the antigenic determinant was much more in the well-differentiated grade than in the poorly differentiated grade. Thus the antigen detected by 4G12 appears to be related to tumor differentiation. Moreover, fluorescence-activated cell sorter analysis demonstrated that the expression of the antigen epitope depended on the cell cycle (G2-M). These data suggest that the 4G12 monoclonal antibody detects a new tumor-associated antigen that is recognized by the human immune system.

Energy deposition evaluation for ultra-low energy electron beam irradiation systems using calibrated thin radiochromic film and Monte Carlo simulations.

For evaluation of on-site dosimetry and process design in industrial use of ultra-low energy electron beam (ULEB) processes, we evaluate the energy deposition using a thin radiochromic film and a Monte Carlo simulation. The response of film dosimeter was calibrated using a high energy electron beam with an acceleration voltage of 2 MV and alanine dosimeters with uncertainty of 11% at coverage factor 2. Using this response function, the results of absorbed dose measurements for ULEB were evaluated from 10 kGy to 100 kGy as a relative dose. The deviation between the responses of deposit energy on the films and Monte Carlo simulations was within 15%. As far as this limitation, relative dose estimation using thin film dosimeters with response function obtained by high energy electron irradiation and simulation results is effective for ULEB irradiation processes management.

Is control of distribution of liposomes between tumors and bone marrow possible?

The objective of this study is to clarify to what extent the accumulation of liposomes from the blood into the tumor and bone marrow can be controlled by liposome size and membrane fluidity. Liposomes with different diameters (50-400 nm) and different membrane fluidity were prepared from hydrogenated egg phosphatidylcholine (HEPC) or egg phosphatidylcholine (EPC), cholesterol (Ch) and dicetylphosphate in various molar ratios. These liposomes were injected intravenously into rats bearing Yoshida sarcoma, and the ratios of the accumulation of liposomes in the tumor to those in the bone marrow, liver and spleen were compared. The tumor-to-bone marrow accumulation ratio increased with the decrease in liposome size from 400 to 50 nm. This ratio was greater than those for the liver and spleen at all sizes. Although tumor-to-liver accumulation ratios of 50- and 100-nm HEPC-containing liposomes were higher than those of EPC-containing liposomes, no obvious difference in tumor-to-bone marrow or tumor-to-spleen accumulation ratios was found between these liposomes. Tumor-to-bone marrow accumulation ratio of HEPC-containing liposomes increased remarkably with the decrease in Ch content from 40 to 30 or 20 mol% compared with ratios for the liver and spleen. Interestingly, the tumor uptake clearance of liposomes of the same size was constant regardless of their membrane fluidity. These findings show that the increases in these accumulation ratios are due to their decreased uptake clearance by the bone marrow. Furthermore, the uptake of 50-nm HEPC-containing liposomes by the bone marrow was specifically inhibited by preinjection of other liposomes, but not when they were exposed in advance to in vivo components. These observations suggest the involvement of in vivo component(s) in the uptake of these liposomes by the bone marrow. We conclude that small HEPC-liposomes with low Ch content show their significantly decreased uptake by the bone marrow due to their decreased recognition by this tissue.

Unique recognition style of tRNA(Leu) by Haloferax volcanii leucyl-tRNA synthetase.

The recognition manner of tRNA(Leu), a class II tRNA characterized by a long variable arm, by leucyl-tRNA synthetase from an extreme halophilic archaea, Haloferax volcanii, was studied using the in vitro transcription system. It was found that the discriminator base (A73) and the long variable arm, especially the specific loop sequence A47CG47D and U47H at the base of this helix, are significant for recognition by LeuRS. An appropriate stem length of the variable arm was also required. Base substitutions in the anticodon arm did not affect the leucylation activity. Transplantation of both the discriminator base and the variable arm of tRNA(Leu) was not sufficient to introduce leucylation activity to tRNA(Ser). Insertion of an additional nucleotide into the D-loop, which is not involved in the direct interaction with LeuRS, converted tRNA(Ser) to an efficient leucine acceptor. This suggests that differences in the tertiary structure play a key role in eliminating tRNA(Ser). The sequence-specific recognition of the long variable arm of tRNA(Leu) has not been observed in any of other organisms reported, such as Escherichia coli, yeast or human. On the other hand, the mode of discrimination from non-cognate tRNAs is similar to that in E. coli in that differences in the tertiary structure play a key role. Similarity extends to the substrate stringency, exemplified by a cross-species aminoacylation study showing that no class II tRNAs from E. coli or yeast can be leucylated by H. volcanii LeuRS. Our results have implications for the understanding of the evolution of the recognition system of class II tRNA.

Monitoring of dye adsorption phenomena at a silica glass/water interface with total internal reflection coupled with a thermal lens effect

Thermal lens spectroscopy was combined with total internal reflectance spectroscopy to develop a novel, highly sensitive analytical method that can detect nonfluorescent as well as fluorescent analytes at surfaces and interfaces. It was verified that when the total internal reflection method is coupled with thermal lens spectroscopy (TIR-TLS), the thermal lens effect is induced by only the evanescent wave. The ability of depth profiling was shown. The detection limit of TIR-TLS was at an absorbance of 3.0 x 10(-5) unit for Sudan II acetone solution, which is better than that of attenuated total reflection by a factor of hundreds. In addition, the adsorption of acridine orange on silanol groups on a glass surface could be monitored directly by TIR-TLS, and the adsorption isotherm agreed well with Langmuir's model. The dependence of surface density of anionic silanol groups on pH was determined by TIR-TLS measurements of aqueous acridine orange solutions buffered in the pH range between 2.7 and 11.5.

Effect of troglitazone on blood insulin levels after pancreas transplantation with systemic venous drainage in rats.

BACKGROUND: Troglitazone is a new oral antidiabetic agent and has been reported to reduce insulin resistance and improve peripheral hyperinsulinemia in patients with noninsulin-dependent diabetes mellitus. To examine the effect of troglitazone on insulin regulation after pancreas transplantation with systemic venous drainage, we measured peripheral glucose and insulin levels and performed an intravenous glucose tolerance test. METHODS: We divided the rats into four groups: diabetic rats with a pancreas graft and administration of troglitazone at 40 mg/day orally (group P+T, n=4), rats with a pancreas graft only (group P, n=4), age-matched normal rats (group N, n=5), and diabetic rats (group DM, n=4). RESULTS: Fasting insulin levels in group P were relatively higher than those in group N, whereas the values in group P+T were normalized. In the intravenous glucose tolerance test, troglitazone clearly regulates sigma immunoreactive insulin levels of pancreas transplanted rats (P vs. P+T: 244+/-23 vs. 145+/-14 microU/ml, P<0.05). CONCLUSION: Hyperinsulinemia induced by systemic venous drainage, which may progress atherosclerosis, can be controlled with troglitazone treatment.

Mediation of skin allograft rejection in scid mice by CD4+ and CD8+ T cells.

We analyzed the role of CD4+ and CD8+ T cells in H-2-disparate skin allograft rejection in the mutant mouse strain C.B-17/Icr scid with severe combined immunodeficiency. On the day of skin allografting, scid mice were adoptively transferred with negatively selected CD4+ or CD8+ splenocytes from normal unsensitized C.B-17/Icr mice. These populations were obtained using a double-mAb--plus--complement elimination protocol using anti-CD4 or anti-CD8 mAb that resulted in no detectable CD4+ or CD8+ cells by FACS and negligible numbers of cytolytic T lymphocytes by limiting dilution analysis in anti-CD8 treated populations. Spleen cells were removed from grafted mice at the time of rejection and were tested in vitro for antidonor reactivity in several assays: mixed lymphocyte culture, cell-mediated lympholysis, and LDA for CTL and for IL-2-producing HTL. The presence of Thy 1.2+, CD4+, or CD8+ cells was determined by FACS. All control C.B-17 mice and scid mice adoptively transferred with nondepleted CD4+, and CD8+ cells rejected skin allografts with similar mean survival times (15.6 +/- 1.5, 18.8 +/- 3.4, 18.0 +/- 5.4, respectively), whereas control scid mice retain skin allografts indefinitely (all greater than 100 days). C.B-17 syngeneic grafts survived indefinitely in all groups. At the time of rejection, splenocytes from scid mice receiving CD4+ cells had negligible donor-specific cytotoxicity in CML and negligible numbers of CTL by LDA, but demonstrated a good proliferative response in MLC and IL-2-producing cells by LDA (frequency = 1/1764). There were no detectable CD8+ cells present by FACS analysis. Conversely, splenocytes from scid mice adoptively transferred with CD8+ cells had strong donor-specific cytotoxicity in CML (58.8% +/- 16.1%) and CTL by LDA (frequency = 1/3448), but no significant proliferation was detected in MLC. There were no detectable CD4+ cells by FACS, but there were small numbers of IL-2-producing cells by LDA (frequency = 1/10,204). These data demonstrate that CD4+ cells adoptively transferred into scid mice are capable of mediating skin allograft rejection in the absence of any detectable CD8+ cells or significant functional cytolytic activity. The adoptive transfer of CD8+ cells also results in skin allograft rejection in the absence of detectable CD4+ cells. The detection of small numbers of IL-2 secreting cells in these mice may indicate that CD(8+)-mediated allograft rejection in this model is dependent on IL-2-secreting CD8+ cells.

The effect of rebamipide on Helicobacter pylori extract-mediated changes of gene expression in gastric epithelial cells.

BACKGROUND: Recent studies have shown that Helicobacter pylori affects intracellular signal transduction in host cells, leading to the activation of transcriptional factors and the induction of pro-inflammatory cytokines. On the other hand, rebamipide, an anti-gastritis and anti-ulcer agent, could scavenge reactive oxygen species and reduce interleukin-8 (IL-8) expression in gastric epithelial cells induced by H. pylori-stimulation through the attenuated activation of nuclear factor-kappaB (NF-kappaB). AIMS: In this study, we investigated the effects of rebamipide on gene expression in H. pylori-stimulated epithelial cells using DNA chip. METHODS: H. pylori water extract (HPE) was prepared from NCTC11637, the type strain of H. pylori. Total RNA was extracted from MKN45 cells, a human gastric cancer cell line, following HPE-stimulation with and without rebamipide for 3 h, and differences in gene expression profiles were observed using GeneChip and Human 6800 probe array. RESULTS: The GeneChip analysis demonstrated that 132 up-regulated genes and 873 down-regulated genes, such as growth factors, chemokines and transcription factors, were detected in MKN45 cells 3 h after stimulation of H. pylori. Among them, several genes, including bFGF, RANTES and MIP-2beta, were previously unknown to be expressed in H. pylori-stimulated human gastric cells. Rebamipide reduced expression of 119 genes encoding cytokines, growth factors and their receptors and transcription factors. CONCLUSIONS: These findings suggest that rebamipide could inhibit inflammatory reactions and tumour progression by modifying H. pylori infection-induced gene expression in gastric epithelial cells.