BACKGROUND: Studies have shown that malondialdehyde is the metabolic product of lipid peroxidation. However, detection of the intermediate metabolic product of lipid peroxidation, acylhydroperoxide (AHP), has rarely been reported. OBJECTIVE: To document concentrations of the intermediate metabolic product of lipid peroxidation, AHP, during different stages of ischemic cerebral infarction. DESIGN, TIME AND SETTING: Forty-eight patients with cerebral infarction from the East Hospital of Tongji University, and thirty-three students of Shanghai Geriatric University (healthy controls), in a case match-control study from April 2000 to January 2001. PARTICIPANTS: Based on different disease states, patients were separated into three groups: acute (n = 19), convalescent (n = 17), and chronic(n = 12). The healthy, control group consisted of 33 students, who were not treated with Vitamin E during the two weeks. METHODS: AHP concentration was detected by an ultraviolet spectrophotometric method, and plasma Vitamin E levels were detected by a visual spectrophotometric method. MAIN OUTCOME MEASURES: Plasma lipid AHP and Vitamin E levels of patients and healthy control groups. RESULTS: Plasma lipid AHP levels of patients in the acute group significantly increased compared with healthy control and convalescent groups (F = 4.40, P < 0.01), but plasma Vitamin E levels significantly decreased compared with the healthy control group (F = 3.07, P < 0.05). In the convalescent group, plasma lipid AHP and the Vitamin E levels were not significantly different from the healthy control (P > 0.05). No significant differences were detected in plasma lipid AHP and Vitamin E levels in the chronic group compared to the control and convalescent groups (P > 0.05). CONCLUSIONS: Lipid peroxidation, as evidenced by high plasma lipid AHP and low Vitamin E levels, occurs primarily during the acute stage of patients with cerebral infarction. BACKGROUND: Studies have shown that malondialdehyde is the metabolic product of lipid peroxidation. However, detection of the intermediate metabolic product of lipid peroxidation, acylhydroperoxide (AHP), has rarely been reported. OBJECTIVE: To document concentrations of the intermediate metabolic product of lipid peroxidation , AHP, during different stages of ischemic cerebral infarction. DESIGN, TIME AND SETTING: Forty-eight patients with cerebral infarction from the East Hospital of Tongji University, and thirty-three students of Shanghai Geriatric University (healthy controls), in a case match -control study from April 2000 to January 2001. PARTICIPANTS: Based on different disease states, patients were separated into three groups: acute (n = 19), convalescent (n = 17), and chronic METHODS group consisted of 33 students, who were not treated with Vitamin E during the two weeks. METHODS: AHP concentration was detected by an ultraviolet spectrophotometric method, a nd plasma Vitamin E levels were detected by a visual spectrophotometric method. MAIN OUTCOME MEASURES: Plasma lipid AHP and Vitamin E levels of patients and healthy control groups. RESULTS: Plasma lipid AHP levels of patients in the acute group significantly increased compared with healthy control and In the convalescent group, plasma lipid AHP and the Vitamin E levels were not (F = 4.40, P <0.01), but plasma Vitamin E levels significantly decreased compared with the healthy control group significantly different from the healthy control (P> 0.05). No significant differences were detected in plasma lipid AHP and Vitamin E levels in the chronic group compared to the control and convalescent groups (P> 0.05). CONCLUSIONS: Lipid peroxidation, as evidenced by high plasma lipid AHP and low Vitamin E levels, due primarily during the acute stage of patients with cerebral infarction.