An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.

Comparison of Helicobacter pylori Eradication Rate in Patients with Non-ulcer Dyspepsia and Peptic Ulcer Diseases according to Proton Pump Inhibitors / 대한소화기학회지

BACKGROUND/AIMS: Conflicting results have been reported whether patients with non-ulcer dyspepsia (NUD) respond differently to Helicobacter pylori (H. pylori) eradication treatment compared with patients with peptic ulcer diseases (PUD). The aim of this study was to evaluate any difference in H. pylori eradication rates between patients with NUD and PUD according to each proton pump inhibitor (PPI). METHODS: From September, 2004 to April, 2007, we retrospectively reviewed 2,297 patients with NUD (1,050 patients) or PUD (1,247 patients) infected with H. pylori. All patients received a standard 1 week triple therapy comprising of one of the five PPIs (pantoprazole, esomeprazole, omeprazole, lansoprazole, rabeprazole), clarithromycin and amoxicillin. The follow-up H. pylori test was performed 4 weeks after the completion of therapy. RESULTS: There was no significant difference in the eradication rates between the two groups. In comparison of eradication rates according to PPI, omeprazole- based triple therapy group showed higher eradication rate than other groups in patients with NUD, but not in patients with PUD. CONCLUSIONS: This study failed to show any difference in H. pylori eradication rate between patients with NUD and PUD. There is no convincing evidence that the eradication rate may be affected by different PPI.

A Randomized, Prospective, Comparative, Multicenter Study of Rabeprazole and Ranitidine in the Treatment of Reflux Esophagitis / 대한소화기학회지

BACKGROUND/AIMS: This study was done to evaluate the efficacy of rabeprazole (proton-pump-inhibitor) and ranitidine (H2-receptor antagonist) in the symptom relief and treatment of erosive esophagitis diagnosed by endoscopy. METHODS: A total of 110 patients with typical gastroesophageal reflux disease (GERD) symptoms were enrolled in this multicenter study. They were randomized into rabeprazole group (53 patients) and ranitidine group (57 patients) respectively. The patients in rabeprazole group were given 10 mg of rabeprazole and ranitidine group received 300 mg of ranitidine before breakfast and dinner for 8 weeks. After the end of treatment, we evaluated the endoscopic healing rate of reflux esophagitis and symptomatic improvement. RESULTS: After 8 weeks of treatment, rabeprazole group showed significantly higher complete endoscopic cure rate than ranitidine group (86.8% [46/53] vs. 57.9% [33/57], p=0.001) and higher symptomatic improvement of heartburn (91.2% [31/34] vs. 76.2% [32/42], p=0.085), especially in the first 7 days (76.7% vs. 45.3%, p=0.008). Also, rabeprazole group showed significantly higher improvement of regurgitation symptom than ranitidine group (100% [35/35] vs. 83% [39/47], p=0.009). Both group showed no differences in the improvement of chest pain and globus sensation. All the adverse events (rabeprazole group 4 events vs. ranitidine group 3 events) were mild and there was no abnormality in laboratory test. CONCLUSIONS: In patients with GERD, rabeprazole 10 mg b.i.d. is superior to ranitidine 300 mg b.i.d. in healing of reflux esophagitis and resolving typical GERD symptoms. Rabeprazole is an effective and well-tolerated drug for GERD treatment.

Helicobacter pylori eradication using tetracycline and furazolidone versus amoxicillin and azithromycin in lansoprazole based triple therapy: an open randomized clinical trial

RACIONAL: Ainda não está estabelecida a melhor terapêutica anti-H. pylori. OBJETIVO: Avaliar a erradicação de H.pylori usando tetraciclina e furazolidona versus amoxicilina e azitromicina em terapia tríplice com lansoprazol no nordeste do Brasil. PACIENTES E MÉTODOS: Cento e quatro pacientes infectados por H. pylori, diagnosticado através do teste rápido da urease e histologia, foram selecionados aleatoriamente para receber: lansoprazol (30 mg q.d.), tetraciclina (500 mg q.i.d.), furazolidona (200 mg t.i.d.) por 7 dias (LTF; n = 52); ou lansoprazol (30 mg b.i.d.) e amoxicilina (1 g b.i.d.) por 1 semana, mais azitromicina (500 mg q.d.) nos primeiros 3 dias (LAAz; n = 52). A erradicação de H.pylori foi avaliada 3 meses após término da terapia através do teste da urease, histologia e teste respiratório usando uréia marcada com 14Carbono. RESULTADOS: A erradicação do H. pylori foi atingida em 46 de 52 (88.4%, 95% CI: 77.5%-95.1%) pacientes no grupo LTF e em 14 de 52 (26.9%, 95% CI: 16.2%-40,1%) pacientes no grupo LAAz. Na análise per-protocolo, a taxa de erradicação foi de 91.8% (95% CI: 81.4%-97.3%) e 28.5% (95% CI: 17.2%-42.3%), respectivamente no grupo de LTF e LAAz. CONCLUSÃO: O esquema com LAAz ofereceu taxas de erradicação inaceitáveis. Por outro lado, o esquema com LTF representa alternativa adequada para erradicação de H.pylori.

A Randomized, Comparative Study of Rabeprazole vs. Ranitidine Maintenance Therapies for Reflux Esophagitis: Multicenter Study / 대한소화기학회지

BACKGROUND/AIMS: Reflux esophagitis is a recurring condition for which many patients require maintenance therapy. This comparative, randomized multicenter study was designed to evaluate the effect of long-term maintenance treatment comparing proton pump inhibitor, rabeprazole and H2 receptor antagonist, ranitidine. METHODS: Eighty four patients with healed reflux esophagitis confirmed by endoscopy were randomly allocated to receive maintenance treatment with either rabeprazole 10 mg once daily or ranitidine 300 mg once daily for 32 weeks. Patients were seen every 8 weeks or at symptomatic relapse. RESULTS: Of 84 initially treated patients, 73 entered the maintenance study. The percentage of asymptomatic patients after 90-day and 210-day treatment were 97% and 81.5%, for rabeprazole and 74.3% and 62.3%, for ranitidine, respectively. After 32 weeks, the relapse rates of esophagitis were 21.3% in the rabeprazole group and 62.9% in the ranitidine group (RR: 0.405, 95% CI: 0.215-0.766). CONCLUSIONS: Maintenance treatment with rabeprazole (10 mg once daily) is superior to ranitidine (300 mg once daily) in keeping the patients with reflux esophagitis in remission over a 32 week period.

Quality of life after peptic perforation.

AIM OF STUDY: Quality of life (QOL) as outcome during treatment of acid peptic disease has been studied, but, peptic perforation, which is the commonest complication of acid peptic disease, has not been studied in the light of QOL outcome. The present-study addresses the important issue of QOL after peptic perforations. METHODS: This prospective study was carried on 51 adult consecutive survivors of peptic perforation managed in Gastrointestinal Surgery Unit, Department of Surgery, Government NSCB Medical College and Hospital, Jabalpur (MP) India. These underwent exploratory laparotomy with repair of perforation, and subsequently were discharged on anti-ulcer therapy (Pantoprazole 40 mg once a day) for 6 weeks. The instrument chosen to study their QOL was gastrointestinal quality of life index (GIQLI). Patients were assessed before they underwent surgery and 3 months and 6 months after operation. RESULTS: The overall GIQLI score (t = 20.1, p < 0.00 at 3 months; t = 8.2, p < 0.001 at 6 months) as well as its G I core (t = 14.5, p < 0.001 at 3 months; t = 7.3, p < 0.001 at 6 months), G I disease specific (t = 12.9, p < 0.001 at 3 months; t = 2.6, p < 0.02 at 6 months), psychological (t = 15.4, p < 0.001 at 3 months; t = 3.5, p < 0.001 at 6 months) and physical and social components (t = 10.9, p < 0.001 at 3 months; t = 4.2, p < 0.001 at 6 months) significantly increased over 3 and 6 months of follow-up, reflecting improvement in quality of life as perceived by the patients. Variations in the pattern of recovery, based on age and gender were not seen in the present study. CONCLUSION: Peptic perforation does not result in any long lasting impairment of QOL and the QOL improves to near normal in 6 months time after the perforation.

Bioequivalence study of rabeprazole sodium on healthy human volunteers.

The newly developed proton pump inhibitor rabeprazole sodium is expected to have beneficial effects in the treatment of peptic ulcer. The pharmacokinetic parameters (C(max), AUC(o-t), t(max)) of this drug have been evaluated to compare the single dose (20 mg) bioavailability of rabeprazole sodium with the standard reference. High performance liquid chromatography (HPLC) coupled with UV detector set at 280 nm has been used to determine plasma concentration of 12 human volunteers as per Drugs Controller General of India (DCGI) guidelines. The method has been validated over a linear range of 20-480 ng/ml from plasma. The minimum quantifiable concentration was set at 10 ng/ml [co-efficient of variance (CV) < 10%]. By comparing AUC(o-t) the relative bioavailability of test preparation has been found to be 100.88% of that of reference preparation.

Significance of Non-erosive Minimal Esophageal Lesions in Gastro-esophageal Reflux Disorder

BACKGROUND: Non-erosive reflux disorder, which represents more than 60% of gastro-esophageal reflux disorders, lacks objective parameters for diagnosis. The purpose of this study was to evaluate the correlation between non-erosive minimal lesions at the lower esophagus and gastro-esophageal reflux disorder. METHODS: Patients were asked to answer a symptom questionnaire. The endoscopic findings were either graded by LA classification or recorded as non-erosive minimal lesions. Patients with minimal lesions were treated with rabeprazole or a placebo and responses were evaluated at weeks 1 and 4. RESULTS: In 8 centers, 3454 patients were screened. In patients with heartburn or acid regurgitation as the most bothersome symptom, 23.7% had endoscopy negative reflux disorder, 40.1% showed minimal lesions, and 36.2% had mucosal break esophagitis. Thirty-four percent of patients with minimal lesions and 39.1% of patients with LA 'grade A' mild esophagitis reported typical reflux symptoms as their main symptom. In patients with minimal lesions, medication with rabeprazole reduced symptoms significantly at weeks 1 and 4, but not with the placebo. CONCLUSION: Patients with non-erosive minimal esophageal lesions had similar reflux symptoms comparable to those with mild erosive reflux esophagitis, and reflux symptoms were improved with a short-term proton pump inhibitor. Thus, non-erosive minimal esophageal lesion constitutes a great part of gastro-esophageal reflux disorder.

Efficacy of Triple Therapy with Rabeprazole for Helicobacter pylori Infection in relation to CYP2C19 Genotype / 대한소화기학회지

BACKGROUND/AIMS: Genetic polymorphism of cytochrome P450 CYP2C19 influences the efficacy of proton pump inhibitor (PPI) in Helicobacter pylori (H. pylori) eradication therapy. We investigated the difference in the cure rates of H. pylori infection by triple (rabeprazole plus amoxacillin and clarithromycin) therapy in relation to CYP2C19 genotype status. METHODS: One hundred and sixteen H. pylori infected patients with gastric ulcer and duodenal ulcer completed the triple therapy with 10 mg of rabeprazole b.i.d., 1,000 mg amoxacillin b.i.d. and 500 mg of clarithromycin b.i.d. for one week. The genotype of CYP2C19 was determined by a PCR-restriction fragment length polymorphism method. RESULTS: According to the univariate analysis, heterozygous extensive metabolizers (hetero EMs) and poor metabolizers (PMs) showed the highest (87.0%) and the lowest (80.0%) eradication rates, respectively. The difference in the therapeutic efficacy of rabeprazole among the different CYP2C19 genotypes was insignificant. With regard to gender, age and smoking history in relation to eradication rate, a statistical significance was noted only with age with odds ratio of 1.063 and p-value of 0.0202. CONCLUSIONS: In the eradication therapy of H. pylori, no statistically significant difference in therapeutic efficacy of rabeprazole was found among different CYP2C19 genotypes.

Pre and post eradication gastric inflammation in Helicobacter pylori-associated duodenal ulcer.

BACKGROUND: Distribution and nature of gastritis are major determinants of clinical outcome of H. pylori infection. The gastric inflammatory changes associated with this infection in developing countries have not been systematically studied. AIMS: To evaluate the inflammatory changes in gastric antrum and corpus in patients with duodenal ulcer and H. pylori infection, before and after H. pylori eradication therapy. METHODS: Histology and H. pylori density were studied in gastric biopsies obtained from 53 consecutive patients with active duodenal ulcer and H. pylori infection. Biopsies were obtained before and 4 weeks after H. pylori eradication therapy, from the anterior and posterior walls of the antrum and corpus, and were evaluated according to the Sydney system. RESULTS: In the pre-H. py/ori eradication antral biopsies, chronic gastritis, active gastritis, atrophy, intestinal metaplasia (IM) and lymphoid follicles / aggregates were seen in 53 (100%), 49 (92%), 11 (21%), 7 (13%) and 28 (53%) patients, respectively. In the corresponding biopsies from gastric corpus, these changes were seen in 49 (92%), 23 (43%), 2 (4%), 2 (4%) and 8 (15%), respectively. All changes except IM were significantly more frequent and of higher grade in the antrum. The grade of chronic gastritis was significantly higher in antrum than corpus; the frequency of gastritis in the antrum and corpus was similar (100% vs. 92%). H. pylori density was also higher in the antrum and correlated well with the grades of chronic gastritis and activity at both sites. Eradication of H. pylori was achieved in 39 patients (74%), and led to significant decrease in gastritis; no change was seen in patients who did not eradicate the organism. CONCLUSIONS: Antral-predominant chronic gastritis and activity are present in more than 90% of patients with H. pylori infection associated with duodenal ulcer, and the grade of gastritis correlates with the density of the organism. Eradication therapy results in improvement of both chronic gastritis and activity.