[Cardiac field potentials and activation sequence in Langendorff perfused heart, cardiac tissue slices and cultured ventricular myocytes recorded by microelectrode arrays system.].

Objective: To observe field potentials (FPs) and activation sequence at Langendorff perfused guinea pigs heart, SD rat cardiac tissue strips perfused by Tyrode's solution and cultured ventricular cardiomyocytes of suckling mice by microeletrode arrays (MEA) technique.

Method: FPs and activation sequence were recorded from perfused heart, cardiac tissue strips (5 mm x 5 mm) and cultured ventricular cardiomyocytes by MEA.

Results: (1) FPs could be recorded in hearts perfused for 30 to 90 min with a heart rate 90 - 120 beats/min.

[Study on the relationship between breast cancer resistance protein expression and 5-fluorouracil resistance].

Objective: To screen breast cancer resistance protein BCRP-mediated resistance agents and to investigate the relations between BCRP expression and drug resistance.

Methods: MT assay was performed to screen BCRP-mediated resistant agents with established BCRP expression cell model. While, the high performance liquid chromatography (HPLC) assay was administrated to measure the related dosage of intracellular retention resistant agents.