METHODS: The present study was a cross-sectional survey conducted from September to November 2001. Schoolchildren were recruited from primary schools that were selected randomly from a list of all primary schools in Petaling Jaya, Malaysia, using random sampling numbers. Information concerning recurrent abdominal pain, socio-economic status, life events, demographic and other details was obtained using a combination of questionnaires and interviews. Academic achievement was assessed using a score based on the Malaysian Primary School Achievement Examination. An overall score at or above the mean was taken to indicate high academic achievement while a score below the mean indicated poor academic achievement.

RESULTS: A total of 1971 children were studied (958 boys and 1013 girls: 1047 Malays, 513 Chinese and 411 Indians). Of these children, 456 (23.1%) fulfilled the criteria for recurrent abdominal pain. Using the method of binary logistic regression analysis, the following factors were found to be independently associated with poor academic performance: a low socio-economic status (odds ratio (OR) 1.30; 95% confidence interval (CI) 1.25-1.35); male sex (OR 1.61; 95% CI 1.26-2.05); the death of a close relative (OR 2.22; 95% CI 1.73-2.85); the divorce or separation of parents (OR 3.05; 95% CI 1.73-5.40); the commencement of work by the mother (OR 1.34; 95% CI 1.02-1.76); hospitalization of the child in the 12 months prior to the study (OR 1.83; 95% CI 1.12-3.01); lack of health-care consultation (OR 1.80; 95% CI 1.36-2.36); missing breakfast (OR 1.47; 95% CI 1.07-2.02); and lack of kindergarten education (OR 1.35; 95% CI 1.04-1.75).

AIM: The present study was conducted to investigate the possible mechanism of actions underlying the systemic antinociception activity of the essential oil of Zingiber zerumbet (EOZZ) in chemical-induced nociception tests in mice.

MATERIALS AND METHODS: Acetic acid-induced abdominal constriction, capsaicin-, glutamate- and phorbol 12-myristate 13-acetate-induced paw licking tests in mice were employed in the study. In all experiments, EOZZ was administered systemically at the doses of 50, 100, 200 and 300 mg/kg.

RESULTS: It was shown that EOZZ given to mice via intraperitoneal and oral routes at 50, 100, 200 and 300 mg/kg produced significant dose dependent antinociception when assessed using acetic acid-induced abdominal writing test with calculated mean ID(50) values of 88.84 mg/kg (80.88-97.57 mg/kg) and 118.8 mg/kg (102.5-137.8 mg/kg), respectively. Likewise, intraperitoneal administration of EOZZ at similar doses produced significant dose dependent inhibition of neurogenic pain induced by intraplantar injection of capsaicin (1.6 μg/paw), glutamate (10 μmol/paw) and phorbol 12-myristate 13-acetate (1.6μg/paw) with calculated mean ID(50) of 128.8 mg/kg (118.6-139.9 mg/kg), 124.8 mg/kg (111.4-139.7 mg/kg) and 40.29 (35.39-45.86) mg/kg, respectively. It was also demonstrated that pretreatment with l-arginine (100mg/kg, i.p.), a nitric oxide precursor significantly reversed antinociception produced by EOZZ suggesting the involvement of l-arginine/nitric oxide pathway. In addition, methylene blue (20mg/kg, i.p.) significantly enhanced antinociception produced by EOZZ. Administration of glibenclamide (10mg/kg, i.p.), an ATP-sensitive K(+) channel antagonist significantly reversed antinociceptive activity induced by EOZZ.