Detection of borderline dosage of malathion intoxication in a rat's brain.

OBJECTIVE: Humans and other animals are liable to expose to low doses of malathion (MAL). However, experimental studies on its toxic threshold dose and toxic low-dose effects have not been conducted. The aims of this study were to detect the initiation of the toxic effects of sub-acute low doses (2.5, 5, and 10 mg/kg) of MAL by immunohistochemical and biochemical parameters in rat brain. MATERIALS AND METHODS: Twenty-eight rats were randomly assigned into four groups (n=7) including control and three different amounts of MAL-exposed groups (2.5, 5, and 10 mg/kg). RESULTS: On immunohistochemical examination, the number of caspase-3-positive cells in all MAL-exposed groups was significantly higher than in the control group. Consistent with this, the total antioxidant capacity, total oxidant status, and the levels of superoxide dismutase, malondialdehyde, and paraoxanase activity were significantly different in the 5 and 10 mg/kg MAL-exposed groups compared with the control group. Additionally, the total oxidant status and malondialdehyde levels were significantly higher in the 5 and 10 mg/kg MAL-exposed groups compared with those in the 2.5 mg/kg MAL-exposed group. CONCLUSIONS: Our results indicate that over 5 mg/kg MAL exposure may result in dose-dependent oxidative stress, increased caspase-3 activity, and launching to the toxic effects in rat brain.

Prophylactic accessory-pathway ablation in asymptomatic patients with a Wolff-Parkinson-White electrocardiographic pattern.

OBJECTIVES: The optimal approach is controversial in asymptomatic patients who are coincidentally found to have evidence of an accessory pathway (AP) on an ECG. The risk of sudden cardiac death (SCD) is low, and the risk of developing symptoms also appears to be low, although a wide range of incidences have been reported. In our trial, we tested the hypothesis that if prophylactic accessory-pathway ablation performed at the time of the initial electrophysiological testing would improve the long-term outcome in asymptomatic patients with a Wolff-Parkinson-White electrocardiographic pattern. PATIENTS AND METHODS: Recruitment of patients began on February 1, 2004, and ended on February 5, 2009. All 110 asymptomatic patients were hospitalized and underwent electrophysiological testing the same day to assess the inducibility of atrioventricular reciprocating tachycardia. The anterograde effective refractory period of the accessory pathway was defined as the longest coupling interval at which anterograde block in the bypass tract was observed. For the statistical analysis, the statistical software SPSS version 15.0 for Windows (SPSS Inc., Chicago, IL, USA). RESULTS: Of 110 asymptomatic patients with a Wolff-Parkinson-White electrocardiographic pattern, 80 patients were ablated. Ablation group consisted of these patients. Control group consisted of remaining 30 and were divided into two groups according to the anterograde effective refractory period of the accessory pathway. There was no significant difference between three groups in terms of arrhythmic events (p: 0.58). CONCLUSIONS: Asymptomatic patients with the Wolff-Parkinson-White syndrome do not require prophylactic ablation, since they remain asymptomatic for many years.