[ ABSTRACT] AIM:To screen out a suitable lead for monitoring the ambulatory electrocardiogram ( ECG) in un-restrained toad, and to investigate its practicability.METHODS:After subcutaneously implanting the electrodes in toads under anaesthesia, the ambulatory ECG of 5 leads were monitored with BL-420S data acquisition and analysis system, and the leads which could well express the waveform in ECG were screened out.The recovery process of the toads from the arti-ficial hibernation within 6 h, the day-to-day stability of the heart rate ( HR) and the heart rate variability ( HRV) in 5 suc-cessive days of hibernation, and the HR and HRV after freeze-thawing process were monitored to determine its practicabili-ty.RESULTS:Two out of 5 leads showed better ECG waveforms.Compared with 6 h post hibernation, lowered HR at 0 h and 1 h was observed, and the standard deviation of normal R-R intervals ( SDNN) was significantly increased ( P<0.05 or P<0.01), but the HR and SDNN from 2 to 5 h showed no significant difference, suggesting that the cardiac function reached the steady state after 2 h recovery.The HR at 2 h and 4 h on day 4 and day 5 decreased significantly compared with that on day 1 (P<0.05 or P<0.01), followed with a significant increase in SDNN (P<0.05 or P<0.01), sugges-ting that the ECG remained stable within 3 d.The HR increased, while SDNN decreased significantly at 1 h and 12 h post-thawing compared with that at pre-freeze (P<0.05), indicating the damaged cardiac function after freeze-thawing process. CONCLUSION:The method of subcutaneously implanting electrodes is suitable for effectively monitoring the ambulatory ECG in toads.

Objective: To explore the value of combined detection of serum cystatin C (CysC), urinary β2-microglobulin (β2-MG), and liver type fatty acid binding protein (L-FABP) in early diagnosis of acute renal injury after cardiac surgery. Methods: 126 patients undergoing cardiac surgery in our hospital from April 2015 to August 2016 were selected as the subjects, according to the occurrence of acute renal injury after operation, 48 cases were divided into acute renal injury (AKI) group and 78 cases into non-acute renal injury (non AKI) group, the levels of serum CysC, urine β2-MG, and L-FABP were detected in the two groups. Receiver operating characteristic (ROC) curve was used to analyze the effects of serum CysC, urine β2-MG, L-FABP in the early diagnosis of acute renal injury after cardiac surgery. Results: The incidence of AKI after cardiac surgery was 38.10% (48/126); the serum CysC level in group AKI was significantly higher than that in non AKI group (P<0.05); the levels of urine β2-MG and L-FABP were significantly higher than those in non AKI group (P<0.05); the area under curve (AUC) of serum CysC for AKI diagnosis after cardiac surgery was 0.874 (P<0.05), with diagnostic sensitivity 85.7%, and specificity 76.5%; the AUC area of urinary β2-MG for AKI diagnosis after cardiac surgery was 0.754 (P<0.05), with diagnostic sensitivity 92.9%, and specificity 73.5%, respectively; the AUC area of urinary L-FABP for AKI diagnosis after cardiac surgery was 0.834 (P<0.05), with diagnostic sensitivity 92.9%, and specificity 74.1%. The AUC area of combined diagnosis of the three was 0.914 (P<0.05), with the diagnostic sensitivity 92.1%, and specificity 82.4%. Conclusions Serum Cys C, urine β 2-MG and L-FABP levels were significantly increased in patients with AKI. The diagnosis of the three alone has a certain reference value, which is lower than the combined diagnosis. The combined diagnosis of the three can provide an important reference for screening acute renal injury after heart surgery.