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Gastric insufflation is common during face mask ventilation and results in unfavourable respiratory events in children. The purpose of this study was to evaluate the effect of a muscle relaxant on gastric insufflation and determine the optimal inspiratory pressure during face mask ventilation in children. Children aged one month to five years were randomly assigned to neuromuscular blocker (NM) or non-neuromuscular blocker (non-NM) groups. After administering intravenous anesthetics, face mask ventilation commenced via pressure-controlled mechanical ventilator. Initial inspiratory pressure was 10 cmH2O and was increased by 2 cmH2O until gastric insufflation was detected via gastric ultrasonography or epigastric auscultation. The primary outcome was the difference in the inspiratory pressure that causes gastric insufflation between the two groups. Diagnostic methods that detect gastric insufflation first were also evaluated. There was no significant difference in the median [interquartile range] inspiratory pressure inducing gastric insufflation between the non-NM (n = 52) and NM groups (n = 60) (18 [16-18] cmH2O vs 18.0 [16-20] cmH2O; median difference, 0 cmH2O; 95% confidence interval [CI], 0 to 2; P = 0.57). The incidence of gastric insufflation increased with increasing inspiratory pressure. Gastric insufflation was detected first by ultrasonography in 44% and by epigastric auscultation in 19% of the non-NM group (difference in percentage, 25%; 95% CI, 6 to 42; P = 0.006) and by ultrasonography in 73% and by epigastric auscultation in 7% of the NM group (difference in percentage, 66%; 95% CI, 50 to 78; P < 0.001). A neuromuscular blocking agent has minimal effect on the inspiratory pressure that causes gastric insufflation during face mask ventilation in children. www.clinicaltrials.gov (NCT02471521); registered 15 June 2015.

BACKGROUND Gastric insufflation frequently occurs during facemask ventilation in children. In the present study, we compared the incidence of gastric insufflation between pressure-controlled facemask ventilation and manual facemask ventilation during general anesthesia induction in children. METHODS Children in the pressure-controlled ventilation group (n = 76) received pressure-controlled facemask ventilation at an inspiratory pressure of 13 cm H2 O. In the manual ventilation group (n = 75), facemask ventilation was manually performed by anesthesiologists, who tried to maintain an inspiratory pressure of 13 cm H2 O. The adjustable pressure limiting valve was set at 13 cm H2 O. The incidence of gastric insufflation during 90 seconds after the initiation of ventilation was assessed using epigastric auscultation and gastric ultrasonography. RESULTS The incidence of gastric insufflation was significantly higher in the manual facemask ventilation group than in the pressure-controlled ventilation group (48% vs 12%, respectively; odds ratio 7.78, 95% confidence interval [CI] 3.38-17.9; P

A series of studies has shown that Helicobacter pylori eradication induces remission in most patients with low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, there have been few reports about the effect of bacterial treatment on the gastric MALT lymphoma in Korea, a well-known H. pylori endemic area. A total of 111 H. pylori-infected patients were prospectively enrolled in Seoul National University Hospital and 99 among them were completely followed up according to our protocol. After H. pylori eradication, tumoural response was evaluated by endoscopy and histopathology every 2-3 months till complete remission (CR) and every 6 months after achieving CR. Median follow-up period was 41 months (range, 11-125 months). Helicobacter pylori was successfully eradicated in all 99 patients and CR was obtained in 84 (84.8%) of 99 patients. The median time to reach CR was 3 months and 94% of CR is in continuous complete remission. Five patients with CR relapsed after 10-22 months without the evidence of H. pylori reinfection. Cumulative recurrence rate was 2.3, 7.7 and 9.3% at 1, 2 and 3 years, respectively. Tumours were mainly located in distal stomach (67.7%) and tumours in distal stomach were associated with more favourable response than those in proximal stomach (P=0.001). Majority of patients with low-grade gastric MALT lymphoma treated by exclusive H. pylori eradication have a favourable long-term outcome, offering a real chance of cure. Tumour location could be a predictive factor for remission following H. pylori eradication.

Endothelial dysfunction associated with many cardiovascular diseases is largely due to reduced nitric oxide (NO) derived from endothelial NO synthase (eNOS). Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene; Pic) is reported to have cardiovascular therapeutic effects. However, the cellular and molecular mechanisms underlying the cardioprotective effects of Pic are still unclear. Here, we investigated whether Pic could influence endothelial NO release in human umbilical vein endothelial cells (HUVECs).In HUVECs exposed to Pic, NO production and phosphorylation of eNOS and protein kinase B (Akt) were determined by using a commercially available NO assay kit and Western blot analysis, respectively.Pic stimulated dose- and time-dependent NO production via eNOS phosphorylation. Pic also stimulated dose-dependent phosphorylation of Akt. Interestingly, NO production and eNOS phosphorylation in response to Pic were significantly abolished by the phosphoinositide 3-kinase (PI3K)/Akt inhibitor LY294002.Pic is capable of inducing eNOS phosphorylation and the subsequent NO release, presumably, by activating PI3K/Akt pathway. The potential efficacy of Pic, a natural hydroxylated analog and a metabolite of resveratrol, may aid in the prevention of cardiovascular diseases characterized by endothelial dysfunction.

The use of warfarin is growing for the prevention or treatment of cardiovascular or cerebrovascular diseases. The risk of haemorrhagic side effects is increased in patients taking warfarin.To evaluate risks related with withholding and resuming anticoagulation in patients with upper gastrointestinal bleeding (UGIB) while on warfarin therapy and the role of the second-look endoscopic examination (SEE).Records of 58 patients with native valvular heart diseases who presented with non-variceal UGIB during chronic anticoagulation with warfarin were retrospectively reviewed. Age- and gender-matched patients with non-variceal UGIB during aspirin therapy because of ischaemic heart disease were recruited as the control group.Development of both recurrent bleeding and thromboembolic events were more frequent in warfarin group than in control group (7.0% vs. 0% with p = 0.03 and 16.7% vs. 2.4% with p0.01, respectively). One of four cases of recurrent bleeding in warfarin group was found by SEE performed in an asymptomatic patient. There were six thromboembolic events which occurred on the 21st, 27th, 28th, 31st, 58th and 75th day from the presentation out of 36 patients who ceased anticoagulation. In contrast, only one from 41 in whom aspirin was discontinued experienced myocardial infarction. There was no difference in the failure of endoscopic haemostasis necessitating angiographic embolisation or surgery, hospital stay, the need of transfusion and overall mortality.Anticoagulation is recommended to be resumed before the 20th day from the cessation to prevent thromboembolic events. A routine SEE before resuming anticoagulation might be helpful to detect asymptomatic recurrent bleeding.

The purpose of this study was to develop a general method for the facile development of a new DNA biosensor which utilizes streptavidin-displayed spores as a molecular machinery.Fluorescence spectroscopy was used as a monitoring tool for the streptavidin displayed on the surface of Bacillus thuringiensis spores and as a diagnosis method for DNA detection. As a proof-of-concept, four pathogenic bacteria including Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumonia were used for the detection of pathogenic species. In addition, a set of mutant variants of Wilson's disease were also used for the detection of single nucleotide polymorphism (SNP) in this system.This strategy, utilizing streptavidin-displayed spores, is capable of capturing DNA targets for the detection of pathogenic bacteria and for mutation analysis in Wilson's disease.This approach could be useful as a simple platform for developing sensitive spore-based biosensors for any desired DNA targets in diagnostic applications.

There has been no report on the response to proton pump inhibitor (PPI) therapy and on-demand or the relapse rate of non-erosive reflux disease (NERD) and erosive oesophagitis in Korea.To compare the risk factors, clinical symptoms and PPI responses between patients with erosive oesophagitis and NERD patients.A survey was performed prospectively in the erosive oesophagitis (205 patients) and NERD group (200 patients). Clinical symptoms, risk factors and PPI responses were analysed. On-demand therapy and the relapse rate of GERD symptoms were investigated during a one-year follow-up.BMIor = 25 (OR 3.0, 95% CI 1.1-8.3), alcohol use (OR 2.9, 95% CI 1.0-8.3), hiatal hernia (OR 5.0, 95% CI 1.2-20) and triglycerideor =150 mg/dL (OR 4.0, 95% CI 1.7-10) were more common in the erosive oesophagitis group than in the NERD group by multivariate analysis. The ratio of oesophageal to extra-oesophageal symptoms was higher in the erosive oesophagitis group compared with the NERD group (P0.001). The PPI response rates at 8 weeks were different (P = 0.02); refractory rates were higher in the NERD group (16.7%) compared with the erosive oesophagitis group (6.0%). However, there was no significant difference between the two groups in on-demand therapy or the relapse rate.These results suggest that the underlying pathogenic mechanisms of erosive oesophagitis and NERD are distinct.

Enterotoxin produced by enterotoxigenic Bacteroides fragilis (BFT) has been associated with mucosal inflammation and diarrhoeal diseases. In this study, the anti-inflammatory molecular mechanism of 5,7-dihydroxy-3,4,6-trimethoxyflavone (eupatilin) was characterized in an HT-29 intestinal epithelial cell line stimulated with BFT. Pre-treatment of HT-29 cells with eupatilin decreased the production significantly of both interleukin (IL)-8 and prostaglandin E(2) induced by BFT in a dose-dependent manner. BFT-activated nuclear factor-kappaB (NF-kappaB) signals in HT-29 cells and pretreatment with eupatilin suppressed NF-kappaB activation that resulted in the significant inhibition of IL-8 and cyclo-oxygenase-2 expression. BFT-induced phosphorylation of both I kappaB alpha and I kappaB kinase (IKK) signals was prevented in eupatilin-pretreated HT-29 cells. Transfection of siRNA for IKK-alpha and IKK-beta decreased the production of IL-8 and prostaglandin E(2); however, the transfection of IKK-beta siRNA showed a more significant reduction of BFT-induced I kappaB alpha phosphorylation compared with that of IKK-alpha siRNA. In addition, herbimycin A, a specific inhibitor of heat shock protein 90 (Hsp90), decreased the BFT-induced activation of IKK and NF-kappaB, suggesting that Hsp90 is associated with a pathway of IKK-NF-kappaB-IL-8/cyclo-oxygenase-2 gene signalling. Furthermore, eupatilin dissociated the complex between Hsp90 and IKK-gamma in BFT-stimulated HT-29 cells. These results suggest that eupatilin can suppress the NF-kappaB signalling pathway by targeting the Hsp90-IKK-gamma complex in intestinal epithelial cells and may attenuate BFT-induced inflammatory responses.

Prospective nationwide multicentre studies that have evaluated endoscopic findings and reflux symptoms using a well-designed questionnaire are very rare.To compare the prevalence rates of and risk factors for erosive oesophagitis and non-erosive reflux disease (NERD) in the Korean population.A gastroscopic examination was performed on 25 536 subjects who visited 40 Healthcare Centers for a health check-up. A gastro-oesophageal reflux questionnaire and multivariate analysis were used to determine the risk factors for erosive oesophagitis and NERD.2019 (8%) and 996 subjects (4%) had erosive oesophagitis and non-erosive reflux disease, respectively; only 58% of subjects with erosive oesophagitis had reflux symptoms. Multivariate analysis showed that the risk factors for erosive oesophagitis and NERD differed, i.e. those of erosive oesophagitis were male, a Helicobacter pylori eradication history, alcohol, body mass indexor =25 and hiatal hernia. In contrast, the risk factors for NERD were female, age40 andor =60 vs. 40-59 years, body mass index23 and a monthly income$1000, glucoseor =126 mg/dL, smoking, a stooping posture at work and antibiotic usage.The prevalence rates of erosive oesophagitis and NERD were 8% and 4%, respectively, in Korean health check-up subjects. The risk factors for erosive oesophagitis and NERD were found to differ, which indicates that their underlying pathogeneses are distinct.

Helicobacter pylori infection elicits persistent neutrophil infiltration in gastric mucosa. The expression of cyclooxygenase (COX)-2 and inhibition of apoptosis in the neutrophils could contribute to the pathogenesis of H. pylori infection. Rebamipide, a mucosal protective and ulcer-healing drug, has been known to inhibit neutrophil activation.To evaluate the effect of rebamipide on the neutrophils activated by H. pylori water-soluble proteins.After neutrophils were stimulated with H. pylori water extract (HPWE) or pre-treated with rebamipide, the expression of COX-2 mRNA and protein was assessed by quantitative RT-PCR and Western blotting, respectively. Prostaglandin (PG) E2 synthesis was determined by radioimmunoassay. Neutrophil apoptosis was evaluated by cytosolic oligonucleosome-bound DNA ELISA and caspase-3 activity was measured by the detection of p-nitroanilide after cleavage from labelled substrate.Stimulation with HPWE up-regulated COX-2 expression and PGE2 secretion, and inhibited neutrophil apoptosis. Rebamipide suppressed PGE2 secretion from neutrophils dose-dependently. Rebamipide, however, did not affect neutrophil apoptosis and caspase-3 activity.Rebamipide effectively suppressed PGE2 secretion from neutrophils activated by H. pylori water-soluble proteins. This is another possible mechanism of gastric mucosal protection by rebamipide.

Tuberculosis has increased in parallel with the acquired immunodeficiency syndrome epidemic and the use of immunosuppressive therapy, and the growing incidence of extra-pulmonary tuberculosis, especially with intestinal involvement, reflects this trend. However, the duration of anti-tuberculous therapy has not been clarified in intestinal tuberculosis.To compare the efficacy of different treatment durations in tuberculous enterocolitis in terms of response and recurrence rates.Forty patients with tuberculous enterocolitis were randomized prospectively: 22 patients into a 9-month and 18 into a 15-month group. Diagnosis was made either by colonoscopic findings of discrete ulcers and histopathological findings of caseating granuloma and/or acid-fast bacilli, or by clinical improvement after therapeutic trial. Patients were followed up with colonoscopy every other month until complete response or treatment completion, and then every 6 months for 1 year and annually. Complete response was defined as a resolution of symptoms and active tuberculosis by colonoscopy.Complete response was obtained in all patients in both groups. Two patients in the 9-month group and one in the 15-month group underwent operation due to intestinal obstruction and perianal fistula, respectively. No recurrence of active intestinal tuberculosis occurred during the follow-up period in either group.Tuberculous enterocolitis can be managed by 9-month chemotherapy without disease recurrence. Further investigations are needed in immunocompromised patients.

Helicobacter pylori eradication has become the standard treatment for duodenal ulcer. However, there is no relevant evidence for antibacterial treatment of the white scar stage of duodenal ulcer (duodenal ulcer scar) in patients with no past history of duodenal ulcer.To investigate whether H. pylori eradication could decrease duodenal ulcer recurrence in patients with duodenal ulcer scar and no past history of duodenal ulcer.We prospectively enrolled 66 patients with duodenal ulcer scar: 53 were H. pylori-positive and 13 were H. pylori-negative. H. pylori-positive patients were randomly assigned into two groups (two-to-one allocation): 36 patients were assigned to the treatment group and 17 to the follow-up group. Thirteen H. pylori-negative patients were followed up according to the study protocol. Follow-up endoscopy was performed to evaluate ulcer scar changes and H. pylori status 6 weeks after anti-H. pylori treatment and then every 6 months for up to 30 months.Active duodenal ulcer recurrence was identified in seven of 23 H. pylori-positive/non-cured patients (30%). There was no duodenal ulcer recurrence in 43 H. pylori-negative/cured patients (0%), which was significantly different in terms of duodenal ulcer recurrence (P=0.001).H. pylori eradication is effective at preventing active duodenal ulcer recurrence in patients with duodenal ulcer scar and no past history of duodenal ulcer.

Proton pump inhibitor-based triple therapies are recommended as the first-line treatment for Helicobacter pylori eradication.To evaluate the efficacies of low-dose clarithromycin triple therapy and tinidazole-containing triple therapy in a metronidazole resistance prevalent area and to compare the efficacies with standard triple therapy.In a randomized, multicentre, prospective study, a total of 352 patients with duodenal ulcer or non-ulcer dyspepsia were randomly divided into three groups according to the administered regimen: OAC250 group (omeprazole, 20 mg, amoxicillin, 1000 mg, and clarithromycin, 250 mg), OAC500 group (omeprazole, 20 mg, amoxicillin, 1000 mg, and clarithromycin, 500 mg) and OTC group (omeprazole, 20 mg, tinidazole, 500 mg, and clarithromycin, 500 mg). The three groups received each regimen twice daily for 7 days. Upper gastrointestinal endoscopy was performed before and 4 weeks after treatment. H. pylori status was determined by rapid urease test and 13C urea breath test.The eradication rates in the OAC250, OAC500 and OTC groups were 76.2%, 65.7% and 64.8% (95% confidence interval: 67.9-84.4%, 56.7-74.8% and 55.7-73.9%), respectively, by intention-to-treat analysis (P=0.149) and 92.8%, 87.2% and 84.1% (95% confidence interval: 84.4-97.3%, 77.9-93.8% and 73.9-91.2%), respectively, by per protocol analysis (P=0.088). All regimens were well tolerated and compliance was excellent.Both low-dose clarithromycin triple therapy and tinidazole-containing triple therapy are effective and safe regimens for H. pylori eradication.

Activation of pro-apoptotic systems has been proven in rejection model of animal heart transplantation. The role of Fas and Fas ligand (FasL) in graft rejection is not fully understood, and the expression changes of these genes in human transplanted heart have not been elucidated.Endomyocardial biopsy samples were taken from 13 consecutive patients undergoing heart transplantation at various times, and they were classified into rejection (REJ, grade 3A or more) and lack of rejection (TOL, grade 1B or less) by International Society of Heart and Lung Transplantation rejection grade. Semiquantitative reverse transcription-polymerase chain reaction and immunohistochemistry were performed to evaluate the status of Fas and FasL expression in each sample.Fas was constitutively expressed both in REJ and TOL specimens (expression levels normalized by glyceraldehyde-3-phosphate dehydrogenase expression in semiquantitative reverse transcription-polymerase chain reaction of REJ vs. TOL, 0.842+/-0.096 vs. 0.848+/-0.103, P=0.776); however, FasL expression was detected in 66% of REJ samples and 40% of TOL samples. Normalized levels of FasL expression were 0.591+/-0.494 (REJ) and 0.383+/-0.507 (TOL) (P0.05). FasL was expressed by cardiomyocytes as well as graft-infiltrating cells.This up-regulation of FasL may be one of possible mechanisms of apoptosis in rejection process of human cardiac allograft.

Helicobacter pylori induces apoptosis and alters the proliferation of gastric mucosal epithelial cells. Cyclooxygenase-2 (COX-2), the inducible form of prostaglandin (PG) synthesis, is known to cause alteration in epithelial cell growth. The goal of this study was to determine whether COX-2 gene expression by H. pylori infection could influence gastric epithelial cell apoptosis. Expression of COX-2 mRNA and proteins was up-regulated in Hs746T gastric epithelial cell lines infected with H. pylori, when assessed by quantitative RT-PCR and western blot. Inhibition of COX-2 expression using NS-398, a specific COX-2 inhibitor, showed a significant increase of gastric epithelial cell apoptosis and caspase-3 activation in Hs746T cells infected with H. pylori. Moreover, the effect of NS-398 on H. pylori-induced apoptosis was reversed by the addition of PGE2. These results suggest that up-regulated COX-2 expression by H. pylori infection can inhibit apoptosis of gastric epithelial cells.

This study was conducted to investigate whether or not the eradication of H. pylori could lead to the regression of intestinal metaplasia (IM) in patients with either duodenal ulcer (DU) or benign gastric ulcer (BGU). The initial antral IM grade was 0.21 in the 72 patients of the H. pylori-eradicated DU group, this decreased to 0.17, 0.14, 0.13, and 0.09 after periods of four weeks, one year, two years, and four years, respectively, but without statistical significance. In the corpus of the DU group, where IM grade was low (0.02), there was no detectable change in IM. The initial antral IM grade of 0.69 in the 41 patients of the H. pylori-eradicated BGU group decreased substantially to 0.61, 0.44, and 0.39 after periods of four weeks and one and two years, respectively, but again without statistical significance. The initial corporal IM grade of the BGU group of 0.27 decreased to 0.20, 0.15, and 0.06 after periods of four weeks and one and two years, again without statistical significance. In contrast, the IM grades of the noneradicated DU group (N = 20) and the BGU group (N = 16) showed nearly no change in the antrum and corpus. Gastritis grades of antrum and corpus in the H. pylori-eradicated DU or BGU group significantly decreased with respect to time (P = 0.0001), but there were no significant changes in the corresponding noneradicated groups. Although there was no statistical significance, IM decreased in the antrum and corpus of the stomach with BGU and in antrum of those with DU over a two to four-year period after H. pylori eradication, suggesting the possible reversibility of IM.

To elucidate the mechanisms of the persistent neutrophil recruitment in H. pylori-infected gastric mucosa, we evaluated the activation of human neutrophils and CXC chemokine expression in neutrophils by H. pylori water-soluble surface proteins. H. pylori water extract (HPWE) was prepared from a supernatant of the H. pylori suspension in distilled water. After neutrophils were stimulated with HPWE, the mobilization of intracellular free calcium, the expression of lymphocyte function-associated antigen-1beta, and the secretion of myeloperoxidase (MPO) were enhanced in the neutrophils. In H. pylori-infected gastric mucosa, transendothelial and transepithelial migration of neutrophils were observed by electron microscopy and mucosal MPO levels were elevated. Up-regulation of the expression of interleukin-8 (IL-8) and growth-related oncogenes (GROs; GROalpha, GRObeta and GROgamma) mRNA and protein in neutrophils by HPWE was demonstrated by quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. In conclusion, H. pylori-induced neutrophil recruitment may be mediated by CXC chemokines which are expressed by neutrophils activated by H. pylori water-soluble surface proteins.

Anti-Helicobacter pylori (H. pylori) treatment for low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma has been the subject of attention. The aim of this study was to determine the proportion of such cases which could be suitable candidates for H. pylori eradication for the purpose of cure; we focused on gross morphology and lymph node metastasis.We retrospectively reviewed the medical records of 53 patients diagnosed and treated for gastric MALT lymphoma at Seoul National University Hospital between 1992 and 1996.According to Isaacson's classification, 60% of cases were low-grade, and H. pylori was detected in 88% of them. In low-grade disease, gastroscopy revealed superficial lesions in 56% of cases, ulcerofungating lesions were found in as much as 19%, and ulceroinfiltrating in 25%. Even in low-grade disease, invasion of proper muscle, or deeper, was seen in 28% of patients, and lymph node involvement in 36%; even in low-grade disease confined to mucosa and submucosa, the rate of lymph node involvement was 40%. All cases which, on gastroscopy, appeared to be gastritis or benign ulcer-like lesions were free of lymph node metastasis, but in low-grade disease, this proportion was only 16%. In 33% of cases, pre-operative clinical stage I--as shown by abdominal CT--was found post-operatively to be stage II. The negative predictive value of lymph node detection by CT was 68%.In low-grade gastric MALT lymphoma, the lymph node involvement rate was too high to be neglected. In detecting lymph node metastasis, the diagnostic accuracy of CT was too low. The proportion of suitable candidates for anti-H. pylori treatment for low-grade gastric MALT lymphoma was not high, and in clinical practice, anti-H. pylori treatment in such cases should at present be very carefully applied.

The pharmacokinetics and the dose proportionality of a new anticonvulsant compound, HEPP (D,L-3-hydroxy-3-ethyl-3-phenylpropionamide) was studied in healthy male volunteers as part of the pharmacological evaluation for new drugs. Study was performed administering doses of 250, 375, 500 and 625 mg of HEPP to six male volunteers. Blood and urine samples were collected for 72 h postdose and analysed by HPLC. Results showed that in man HEPP is rapidly absorbed from the gastrointestinal tract. Tmax values were between 1.5 and 6.0 h. Plasma mean terminal half-life after the different doses ranged between 15.83 and 27.62 h with an overall harmonic mean value of 22.8. The mean AUC0-infinity and Cmax increased linearly with doses of 250, 375 and 500 mg but not with the dose of 625 mg. The amount of unchanged drug excreted in urine was between 3 and 6% of administered dose which shows an extensive metabolism of the drug.

The protozoan parasite, Entamoeba histolytica, is one of major causative agents of intestinal disease all over the world. In acute experimental infection, the early host response to E. histolytica is characterized by an infiltration of neutrophils. However, the chemotactic signal for this response is not well known. Based on the finding that human epithelial cells produce the potent neutrophil chemoattractant and activator, interleukin-8 (IL-8), IL-8 gene expression was examined thoroughly in human colon epithelial cells exposed to E. histolytica trophozoites. Cellular RNAs were extracted from HT-29 or Caco-2 human colon epithelial cells exposed to E. histolytica trophozoites for 30 minutes, 1 and 3 hours. IL-8 mRNA transcripts were measured by reverse transcriptional polymerase chain reaction (RT-PCR) using synthetic standard RNA. The number of IL-8 mRNA molecules increased from 30 minutes to 3 hours of exposure period, reaching 3.1 x 10(7) molecules/micrograms of total RNA. Expression pattern of IL-8 mRNA transcripts was parallel to the amounts of IL-8 protein measured by enzyme-linked immunosorbent assay (ELISA). Lysates of E. histolytica also induced expression of mRNA for IL-8 in colon epithelial cells. These results suggest that acute inflammatory reaction by E. histolytica may be initially triggered by proinflammatory cytokines such as IL-8 secreted from epithelial cells of the colon.