HSP90 inhibitor enhances anti-proliferative and apoptotic effects of celecoxib on HT-29 colorectal cancer cells via increasing BAX/BCL-2 ratio.

Due to the high prevalence and mortality rate of colorectal cancer (CRC), new treatment approaches like combination therapy seem to be necessary. The relationship between chronic inflammation and colorectal cancer development and progression has been shown to be important. Celecoxib, a selective COX-2 inhibitor, is the only non-steroidal anti-inflammatory drug (NSAID) that has been approved for cancer therapy and prevention. Because of cardiovascular side effects of COX-2 inhibitors, combination therapy may improve the therapeutic profile. 17-Demethoxy-17-allylamino geldanamycin (17-AAG), a heat shock protein 90 (HSP90) inhibitor, shows anti-inflammatory effects via down-regulation of the key mediators of inflammation such as Nuclear Factor κB (NF-kB), JAK/Signal Transducer and Activator of Transcription (JAK/STAT). Thus, we studied the effect(s) of combination of 17-AAG and celecoxib on HT-29 cells viability and apoptosis induction. Based on MTT results, we showed an increase in the inhibitory effect of celecoxib when combined with 17-AAG, especially at low a concentration of celecoxib.  Flow cytometry analysis demonstrated that apoptosis induction is probably the mechanism of additive inhibitory effects of 17-AAG and celecoxib combination. To explore the possible mechanism of apoptosis induction by 17-AAG and celecoxib combination, levels of BAX and BCL-2 proteins were determined by western blotting. The BAX/BCL-2 ratio in the combination group was increased compared to 17-AAG or celecoxib alone, mainly via decreasing BCL-2 levels. In conclusion, 17-AAG, increased inhibitory effects of celecoxib on HT-29 cells, probably by induction of apoptosis.

HSP90 Inhibition Suppresses PGE2 Production via Modulating COX-2 and 15-PGDH Expression in HT-29 Colorectal Cancer Cells.

The existence of multiple-interactive roles between several signaling pathways in tumorigenesis shows the significance of pharmacological factors like heat shock protein 90 (HSP90) inhibitors which control several signaling pathways simultaneously. HSP90 as a molecular chaperone supports the active conformational structure and function of several oncogenic signal proteins, termed "client" proteins, some of them act as a link between cancer and inflammation. Prostaglandin E2 (PGE2) is one of the major mediators of inflammation in colorectal cancer development and progress. However, the relationship between chaperone activity of HSP90 and PGE2 levels remains unclear. We evaluated the inhibitory effects of 17-demethoxy-17-allylamino geldanamycin (1 7-AAG), an HSP90 inhibitor, on PGE2 levels in HT-29 colorectal cancer cells. For the first time, we showed inhibitory effects of 17-AAG, on PGE2 levels in HT-29 colorectal cancer cells. 17-AAG inhibited PMA-induced cyclooxygenase-2 (COX-2) mRNA expression and protein level. We showed 15-hydroxyprostaglandin dehydrogenase (15-PGDH) expression induced by 17-AAG treatment at both mRNA and protein levels. In conclusion, we found that inhibitory effects of 17-AAG on PGE2 levels in HT-29 colorectal cancer cells were mediated through modulating COX-2 and 15-PGDH expression.

Expression levels of heat shock protein 60 and glucose-regulated protein 78 in response to trimethylamine-N-oxide treatment in murine macrophage J774A.1 cell line.

Trimethylamine N-oxide (TMAO), a common metabolite in animals and humans, can induce changes in the expression or conformation of heat shock proteins. It has also been introduced as a risk factor for atherosclerosis and a biomarker for kidney problems. On the other hand, increased levels of heat shock proteins 60 and 70 KDa are associated with increased atherosclerosis risk. This study was therefore designed to evaluate the possible effect(s) of TMAO on the expression of HSP60 and GRP78 at the mRNA and protein levels. Murine macrophage J774A.1 cells were treated with micromolar concentrations of TMAO and 4-phenylbutyric acid (4-PBA), a chemical chaperon, for different time intervals. Tunicamycin was also used as a control for induction of endoplasmic reticulum stress. Tunicamycin greatly increased both mRNA and protein levels of GRP78. Similarly but to a lesser extent compared to tunicamycin, TMAO also increased mRNA and protein levels of GRP78 in a dose and time-dependent manner. In contrast, 4-PBA failed to induce any changes. Similar to GRP78, HSP60 was also increased only at mRNA level in TMAO treated cells. 4-PBA also increased HSP60 mRNA levels, whereas, tunicamycin did not show any effect on either protein or mRNA levels of HSP60. Since both heat shock proteins are stress inducible and the elevation of GRP78 is a hallmark for endoplasmic reticulum stress induction, it can be concluded that TMAO may induce endoplasmic reticulum stress or may act through elevation of these heat shock proteins.

Tetracycline-regulated expression of OLIG2 gene in human dental pulp stem cells lead to mouse sciatic nerve regeneration upon transplantation.

Numerous studies have indicated dental pulp stem cells (DPSCs) potency to differentiate into several types of cell lineages. Oligodendrocyte lineage transcription factor 2 (OLIG2) plays an important role in the oligodendrogenic pathway. In this study, a tetracycline (Tet)-inducible system expressing OLIG2 gene was transfected into human DPSCs to direct their differentiation toward oligodendrocyte progenitor cells (OPCs). Following induction, the expression of stage-specific markers was studied by Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR), immunocytochemistry and western blotting. In the following, the cells were transplanted into the mouse model of local sciatic demyelination damage by lysolecithin. Recovery of lysolecithin-induced lesions in sciatic nerve was studied by treadmill exercise, von Frey filament test and hind paw withdrawal in response to a thermal stimulus. Improvement of behavioral symptoms was efficiently observed from the second week to the sixth week post-transplantation. Our findings showed that exogenous expression of the OLIG2 gene by a Tet-regulated system could be used as an efficient way to induce the differentiation of DPSCs into functional oligodendrocytes. Meanwhile, the DPSC-derived OPCs have relevant therapeutic potential in the animal model of sciatic nerve injury and therefore might represent a valuable tool for stem cell-based therapy in inflammatory and degenerative diseases of the peripheral and central nervous systems (CNSs).

Meta-analysis: rectal indomethacin for the prevention of post-ERCP pancreatitis.

BACKGROUND: Despite initial evidence in the literature, nonsteroidal anti-inflammatory drugs (NSAIDs) have not been widely used to prevent post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). AIM: To complete a meta-analysis of high-quality RCTs that included the latest available literature published after past meta-analytical efforts METHODS: A comprehensive electronic literature search was carried out for RCTs comparing peri-procedural rectal indomethacin and placebo in preventing PEP. Methodological quality was assessed by the Cochrane risk of bias tool. Fixed model Mantel-Haenszel meta-analysis, Q test and I(2) index were used. Several subgroup and sensitivity analyses were planned. RESULTS: A total of four of 61 retrieved trials between 2007 and 2012 (n = 1470) were included. No significant publication bias existed. All studies used similar criteria to detect pancreatitis. The pooled proportion estimate of the rate of pancreatitis was 5.1% with indomethacin and 10.3% with placebo. After excluding the high-risk patients, the rates were 3.9% and 7.9% respectively. Fixed model meta-analysis showed that the rate of pancreatitis was significantly lower using indomethacin as compared with placebo [OR = 0.49(0.34-0.71); P = 0.0002]. Number needed to treat was 20. There was no significant statistical or clinical heterogeneity. In subgroup analysis, the difference remained unchanged for average-risk population [OR = 0.49(0.28-0.85); P = 0.01] or in preventing severe PEP [OR = 0.41(0.21-0.78); P = 0.007]. The result of the main outcome remained robust in multiple sensitivity analyses. CONCLUSIONS: Rectal indomethacin used immediately before or after ERCP significantly reduces the risk of PEP to half in both low- and high-risk patients, and with both statistically and clinically significant conclusions. These results suggest that a possible change in routine practice for patients at both low and high risk of developing PEP should be advocated.

The role of GABAergic system on the inhibitory effect of ghrelin on food intake in neonatal chicks.

Ghrelin is a gut-brain peptide that has a stimulatory effect on food intake in mammals. In contrast, this peptide decreases food intake in neonatal chicks when injected intracerebroventricularly (ICV). In mammals, neuropeptide Y (NPY) mediates the orexigenic effect of ghrelin whereas in chicks it appears that corticotrophin releasing factor (CRF) is partially involved in the inhibitory effect of ghrelin on food intake. Gamma aminobutyric acid (GABA) has a stimulatory effect on food intake in mammals and birds. In this study we investigated whether the anorectic effect of ghrelin is mediated by the GABAergic system. In Experiment 1, 3h-fasted chicks were given an ICV injection of chicken ghrelin and picrotoxin, a GABA(A) receptors antagonist. Picrotoxin decreased food intake compared to the control chicks indicating a stimulatory effect of GABA(A) receptors on food intake. However, picrotoxin did not alter the inhibitory effect of ghrelin on food intake. In Experiment 2, THIP hydrochloride, a GABA(A) receptor agonist, was used in place of picrotoxin. THIP hydrochloride appeared to partially attenuate the decrease in food intake induced by ghrelin at 30 min postinjection. In Experiment 3, the effect of ICV injection of chicken ghrelin on gene expression of glutamate decarboxylase (GAD)(1) and GAD(2), GABA synthesis enzymes in the brain stem including hypothalamus, was investigated. The ICV injection of chicken ghrelin significantly reduced GAD(2) gene expression. These findings suggest that ghrelin may decrease food intake in neonatal chicks by reducing GABA synthesis and thereby GABA release within brain feeding centers.

FoxP3 overexpression and CD1a+ and CD3+ depletion in anal tissue as possible mechanisms for increased risk of human papillomavirus-related anal carcinoma in HIV infection.

AIM: We analysed local cellular and humoral immunity factors in the anal mucosa in an attempt to explain how HIV infection increases the risk of anal cancer in HPV-infected patients. METHOD: HIV-positive cases and matched HIV-negative controls with more than one recurrence of condylomas were included in a prospective study following treatment of the initial lesions. Patients were followed every 3 to 6 months for the development of anal intraepithelial neoplasia (AIN3) and cancer for up to 60 months. Tissue CD1a(+), CD3(+), CD4(+), CD8(+) cells and mRNAs of selected cytokines and chemokines were quantified and compared in patients with or without AIN3 or cancer using morphometric or immunohistochemistry analysis and qRT-PCR. RESULTS: Sixty-six individuals (22 patients and 44 controls) were included. In the case group, CD1a(+) and CD3(+) cell counts were significantly lower in biopsies from AIN3 and cancer specimens compared with those from AIN 1-2 or normal biopsies (P < 0.0001). A CD1a(+) count of < 10/mm was predictive of AIN3 and cancer (Odds ratio = 9.4, 95% CI: 5.4-18.3, P < 0.0001). IL-8 and IL23 levels were significantly higher in cancer than in non-cancer tissues regardless of HIV status (P = 0.02). FoxP3 expression was significantly higher in HIV-infected cases than in controls with AIN3/cancer (P < 0.04). CONCLUSION: Depletion of CD1a(+) and CD3(+) cells and overexpression of FoxP3 in the anal mucosa appear likely to contribute to the risk of HPV-related anal cancer in HIV-infected patients. Furthermore, overexpression of IL-8 and IL-23 in the anal mucosa might be responsible for the development of this cancer regardless of HIV status.

Family history and the risk of gastric cancer.

Both environmental and genetic factors have a role in the aetiology of gastric cancer. The nature of the genetic factors has not been well-studied and, outside of a few rare cancer syndromes, the genes involved have not been identified. Having a first-degree relative with gastric cancer is a consistent risk factor for gastric cancer, although the magnitude of the odds ratio (OR) associated with a positive family history varies with the ethnic group and with the geographic region. In published case-control studies, the odds ratio varies from approximately 2 to 10, depending on the country. Unlike other common adult cancers, the risk of gastric cancer in migrants is similar to that of the population of origin and does not approach that of the host population in the first generation post-migration. It is hoped that molecular studies, including genomewide association studies (GWAS), will illuminate the genetic factors underlying this important association.

Oxyntomodulin reduces expression of glucagon-like peptide 1 receptor in the brainstem of chickens.

Oxyntomodulin (OXM) is a peptide released from the gut and attenuates food intake by acting on hypothalamus. However, its role at the molecular level is not well studied. In the first section of this study, we analysed the effect of OXM on food intake behaviour after injecting into the lateral ventricle of chickens. The outcome showed that food intake decreased significantly after administering 4 nmol of OXM. In the second part, the expression of glucagon-like peptide 1 receptor (GLP-1R) in the brainstem was analysed by real-time RT-PCR. The results showed that expression of GLP-1R was reduced to 27% and 16% at 30 and 90 mins after injection of OXM respectively. In saline-injected chickens, no reduction in GLP-1R was seen. It can be concluded that OXM has a down regulatory effect on the responding receptor, GLP-1R and OXM in chicks has the same reductive effect on food intake as in the mammals.

The pharmacodynamics and pharmacokinetics of S-tenatoprazole-Na 30 mg, 60 mg and 90 mg vs. esomeprazole 40 mg in healthy male subjects.

BACKGROUND: Racemic tenatoprazole 40 mg/day provides more prolonged acid suppression than esomeprazole 40 mg/day. AIM: To compare pharmacodynamic and pharmacokinetic profiles of tenatoprazole and esomeprazole. METHODS: A single-centre, double-blind, double-dummy, randomized, 4-way, cross-over study was conducted in 32 healthy male subjects. S-tenatoprazole-Na 30, 60 or 90 mg, or esomeprazole 40 mg was administered once daily for 5 days with 10-day washout intervals. The 24-h intragastric pH was recorded at baseline and on day 5 of each period. RESULTS: On day 5, median pH (5.34 +/- 0.45 and 5.19 +/- 0.52 vs. 4.76 +/- 0.82, respectively, P < 0.002) and percentage time with pH > 4 (80 +/- 11 and 77 +/- 12, vs. 63 +/- 11 respectively, P < 0.0001) for 24-h were higher with S-tenatoprazole-Na 90 mg and 60 mg than esomeprazole. In nocturnal periods, S-tenatoprazole-Na 90 mg, 60 mg and 30 mg were superior to esomeprazole with regard to median pH (5.14 +/- 0.64, 4.94 +/- 0.65, 4.65 +/- 0.86 and 3.69 +/- 1.18 respectively, P < 0.0001) and percentage time with pH > 4 (77 +/- 12, 73 +/- 17, 64 +/- 17 and 46 +/- 17 respectively, P < 0.0001). Proportion of subjects with nocturnal acid breakthrough with S-tenatoprazole-Na 90 mg, 60 mg and 30 mg was significantly less than with esomeprazole (54.8, 43.3, 56.7 and 90.3 respectively, P < 0.04). The proportion of subjects with >16 hrs with pH >4 was significantly higher with S-tenatoprazole-Na 90 mg and 60 mg than with esomeprazole (87.1%, 83.3% and 41.9% respectively, P < 0.02). CONCLUSIONS: S-tenatoprazole-Na produced significantly greater and more prolonged dose-dependent 24-h and nocturnal acid suppression than esomeprazole. S-tenatoprazole-Na may provide greater clinical efficacy compared with current PPIs for patients with ineffective once-daily therapy.

Predictable prolonged suppression of gastric acidity with a novel proton pump inhibitor, AGN 201904-Z.

BACKGROUND: AGN 201904-Z is a new, slowly absorbed, acid-stable pro-proton pump inhibitor (pro-PPI) rapidly converted to omeprazole in the systemic circulation giving a prolonged residence time. AIM: To investigate pharmacodynamics and pharmacokinetics of AGN 201904-Z compared to esomeprazole. METHODS: A randomized, open-label, parallel group, investigator-blinded intragastric pH study was conducted in 24 healthy Helicobacter pylori negative male volunteers. AGN 201904-Z enteric-coated capsules (600 mg/day) or esomeprazole delayed-release tablets (40 mg/day) were administered for 5 days. Twenty-four-hour intragastric pH recordings were acquired at baseline, days 1, 3 and 5 with blood levels of omeprazole, AGN 201904-Z and gastrin. RESULTS: On day 1, median nocturnal pH and proportion of nocturnal time with pH >or=4 and 24-h and nocturnal time pH >or=5 were significantly higher with AGN 201904-Z than esomeprazole. At day 5, 24-h and median nocturnal pH were significantly higher for AGN 201904-Z than esomeprazole (P < 0.0001). There was also a marked reduction in periods of nocturnal pH <4.0. Area under curve of the AGN 201904-Z active metabolite (omeprazole) in the blood was twice that of esomeprazole at day 5. CONCLUSIONS: AGN 201904-Z produced a significantly greater and more prolonged acid suppression than esomeprazole, and nocturnal acid suppression was more prolonged over all 5 days. AGN 201904-Z should provide true once-a-day treatment and better clinical efficacy than current PPIs.

Injection of botulinum toxin before pneumatic dilatation in achalasia treatment: a randomized-controlled trial.

BACKGROUND: Pneumatic dilatation is the first line therapy in achalasia, but half of patients relapse within 5 years of therapy and require further dilatations. AIM: To assess whether botulinum toxin injection before pneumatic dilatation is superior to pneumatic dilatation alone in achalasia patients. METHODS: Newly diagnosed achalasia patients were randomly assigned to receive botulinum toxin 1 month before pneumatic dilatation (botulinum toxin-pneumatic dilatation group: 27 patients with median age of 38) or to undergo pneumatic dilatation alone (pneumatic dilatation group: 27 patients with median age of 30). Response to therapy was assessed by clinical and objective methods at various intervals. RESULTS: One-year remission rate of patients in botulinum toxin-pneumatic dilatation group was 77% compared with 62% in pneumatic dilatation group (P = 0.1). In pneumatic dilatation group, the oesophageal barium volume significantly (P < 0.001) decreased at 1 month, but this reduction did not persist over 1-year follow-up. Botulinum toxin-pneumatic dilatation group showed a significant (P < 0.001) reduction in barium volume at the various times intervals post-treatment. In the botulinum toxin-pneumatic dilatation group, 10/11 (91%) patients over 40 were in remission at 1 year, comparing with only five of nine (55%) cases in pneumatic dilatation group (P = 0.07). CONCLUSION: Injection of botulinum toxin before pneumatic dilatation does not significantly enhance the efficacy of pneumatic dilatation.

Lower oesophageal sphincter pressure and timed barium oesophagogram: two objective parameters in the non-invasive assessment of primary achalasia.

BACKGROUND: The non-invasive assessment of primary achalasia is not precise. AIM: To compare investigations before and 1 month after balloon dilation in achalasia. METHODS: Fifty-two patients with primary achalasia were enrolled. Subjective and objective variables of oesophageal functions were analysed before and 1 month after balloon dilation. RESULTS: The mean predilation symptom score, lower oesophageal sphincter pressure, height and volume of barium at 5 min were 7.7 +/- 2.6, 62.0 +/- 25.1 mmHg, 9.2 +/- 6.1 cm and 53.2 +/- 49.8 mL respectively; the mean postdilation values were 3.0 +/- 3.0, 34.1 +/- 12.5 mmHg, 7.9 +/- 5.1 cm and 28.0 +/- 30.1 mL respectively. The before dilation volume of barium at 5 min correlates significantly with lower oesophageal sphincter pressure (P < 0.01). The mean symptom scores, lower oesophageal sphincter pressure and volume of barium at 5 min dropped significantly after intervention (P < 0.01), but the reduction in barium height at 5 min was not significant. The percentage changes in volume at 5 min significantly predicted the percentage changes in lower oesophageal sphincter pressure (P < 0.01). CONCLUSIONS: The volume of barium retention at 5 min can predict the lower oesophageal sphincter pressure before and after balloon dilation in primary achalasia. This could be used as a non-invasive objective tool for initial and post-dilation assessment.

Prevalence of intestinal parasitic infections in the Islamic Republic of Iran.

A national survey of the prevalence of intestinal parasitic infections in the Islamic Republic of Iran was made on a random sample of families covered by local health centres affiliated to the medical universities. Out of 53,995 people aged 2+ years, from 12,495 families (0.1% of all families in 1999), 45,128 stool samples were analysed by formalin-ether precipitation. Intestinal parasitic infections were found in 19.3% of the study population (19.7% male, 19.1% female). Giardia lamblia (10.9%), Ascaris lumbricoides (1.5%), Entamoeba histolytica (1.0%) and Enterobius vermicularis (0.5%) were the most common infections. The infection rate was highest in the 2-14 years age group (25.5%) and in rural residents (23.7%).

Prevalence of intestinal parasitic infections in the Islamic Republic of Iran

A national survey of the prevalence of intestinal parasitic infections in the Islamic Republic of Iran was made on a r and om sample of families covered by local health centres affiliated to the medical universities. Out of 53,995 people aged 2+ years, from 12,495 families [0.1% of all families in 1999], 45,128 stool samples were analysed by formalin-ether precipitation. Intestinal parasitic infections were found in 19.3% of the study population [19.7% male, 19.1% female]. Giardia lamblia [10.9%], Ascaris lumbricoides [1.5%], Entamoeba histolytica [1.0%] and Enterobius vermicularis [0.5%] were the most common infections. The infection rate was highest in the 2-14 years age group [25.5%] and in rural residents [23.7%]

Efficacy of botulinum toxin injection before pneumatic dilatation in patients with idiopathic achalasia.

Graded pneumatic dilatation (PD) is an appropriate long-term therapy and botulinum toxin injection (BT) is a relatively short-term therapy in idiopathic achalasia. Their combination has not been previously scrutinized. This study aimed to evaluate the role of BT in enhancing the efficacy of PD with 30 mm balloons. Patients who underwent PD with 30 mm balloons after botulinum toxin injections and a group of age- and sex-matched controls who were treated only with PD were enrolled in the study. Symptom scores were taken before, 1 month after and then every 3 months after PD. There were no significant differences between the two groups in gender, duration or severity of symptoms. One of the 12 patients in the case group relapsed 30 months after PD but the others were in remission for an average of 25.6 months. In the control group, all the patients relapsed after a mean of 12.6 months and needed a 35-mm PD. The cumulative remission rate was significantly higher in the case group compared with the control group (P < 0.01). The mean symptom score decreased by 76% in the case group (P < 0.001) and 53% in the controls (P < 0.01) at the end of the first month. Neither age, sex, nor duration or severity of symptoms were predictive of patients' responses to treatment. It seems that BT may be a meaningful enhancing factor in long-term efficacy of PD. PD with a 30 mm balloon after a BT session may resolve the need for the future higher grade PD.

Pneumatic balloon dilatation in achalasia: a prospective comparison of safety and efficacy with different balloon diameters.

BACKGROUND: Pneumatic dilatation is considered to be the first line therapy for achalasia, but long-term outcome studies are scarce and limited by their retrospective design. There is also no consensus on the optimal method for performing pneumatic dilation as regard to balloon diameter, amount and the rate inflation pressure. AIM: To address these questions in a large long-term prospective study. METHODS: Over a period of 10 years 262 achalasia patients referred to our centre were enrolled. All patients underwent a pre-treatment clinical evaluation and were followed every 6 months. The first 62 patients (group A) underwent dilatation with initial use of a 35 mm balloon with inflation pressure of 10 psi in 10 seconds (s). In group B (200 patients) we initially used a 30 mm balloon with inflation pressure of 10 psi in 30 s. Dilatation was repeated with incrementally larger balloons (35 and 40 mm) in case of relapse. We used rigiflex balloon and maintained pressure for 60 s after inflation in both groups. RESULTS: Three perforations occurred in group A whereas no perforation took place in Group B. The cumulative proportional remission rate with single dilatation in groups A and B decreased from 83 and 75% in 6 months to 60 and 57% after 30 months of therapy respectively, the differences did not reach statistical significance. In patients who had undergone further dilatations the probability of remaining in remission at 1 year after the first and the second dilatation was 38 and 88% in group A, 20 and 89% in group B respectively. The probability of remaining in remission for 2 years increased from 20% after the first dilatation to 70% after the second dilatation. CONCLUSION: Graded pneumatic balloon dilatation with 30 mm diameter and slower rate of balloon inflation is an effective and safe initial method of therapy for achalasia. The duration of remission can be extended by repeated dilatation with larger size balloon.

Randomized controlled trial comparing botulinum toxin injection to pneumatic dilatation for the treatment of achalasia.

BACKGROUND: Therapeutic options for achalasia include pharmacological therapy, surgical myotomy, pneumatic dilatation and intrasphincteric botulinum toxin injection. AIM: To compare botulinum toxin injection with pneumatic dilatation in a randomized trial. PATIENTS/METHODS: Forty adults with newly diagnosed achalasia were randomized to receive botulinum toxin (n=20) or pneumatic dilatation (n=20). Symptom scores were evaluated at 1, 6 and 12 months. Clinical relapse was defined as a symptom score greater than 50% of baseline. Relapsers received a second botulinum toxin injection or pneumatic dilatation. RESULTS: The cumulative 12-month remission rate was significantly higher after a single pneumatic dilatation (53%) compared to a single botulinum toxin injection (15%)(P < 0.01). The 12-month estimated adjusted hazard for relapse and need for retreatment for the botulinum toxin group was 2.69 times that of the pneumatic dilatation group (95% confidence interval; 1.18-6.14). When a second treatment was administered to the relapsers in each group, the cumulative remission rate 1 year after initial treatment was significantly higher in the pneumatic dilatation group (100%) compared to the botulinum toxin group (60%) (P < 0.01). There were no major complications in either group. CONCLUSIONS: Pneumatic dilatation is more efficacious than botulinum toxin in providing sustained symptomatic relief in patients with achalasia. The efficacy of a single pneumatic dilatation is similar to that of two botulinum toxin injections.