RESUMO
BACKGROUND: To evaluate whether the frequency variation of ventricular fibrillation (VF) helps to predict successful defibrillation in a rat model of cardiac arrest. METHODS: VF was induced in rats followed by cardiopulmonary resuscitation and then defibrillation. The electrocardiographic signals of 30 rats with first-shock success were obtained from our previous animal experiments, and 300 rats without first-shock success were selected as control. The VF waveform immediately before the first defibrillation was analyzed. RESULTS: Eighty-eight percentages of the frequency variations of an electrocardiogram (ECG) record falling in the range -9.5-9.5 Hz was selected with sensitivity of 0.8, specificity of 0.583, and area under curve (AUC) of 0.708. Compared with amplitude spectrum area (AMSA) (sensitivity = 0.767, specificity= 0.547, and AUC = 0.678), combining frequency variation and AMSA significantly increases the predictability with sensitivity of 0.933, specificity of 0.493, and AUC of 0.732 (p = 0.005). CONCLUSIONS: The frequency variation of VF may serve a useful parameter to predict defibrillation success.
RESUMO
To investigate the pharmacokinetic characteristics of active constituents of Guhong injection in rats with cerebral ischemia reperfusion injury. The middle cerebral artery occlusion (MCAO) model was established in our studies, and then all the rats received iv administration of Guhong injection (2.1 mL·kg⁻¹). The blood concentrations of aceglutamide and hydroxysafflor yellow A (HSYA) were determined by high performance liquid chromatography (HPLC) method at different time points. The concentration-time curves were drawn and pharmacokinetic data were obtained by DAS 3.2.6 software. The results showed that aceglutamide and HSYA showed good linear relationship within the ranges of 1.5-500 mg·L⁻¹ (R²=0.997 5) and 0.33-40 mg·L⁻¹ (R²=0.998 9) respectively. This quantitative method showed a high recovery rate, good precision and stability. The main pharmacokinetics parameters of t1/2α, t1/2β, CL₁, CL₂, AUC0-t, AUC0-∞, Vd1, and Vd2 were (0.139±0.007) and (0.155±0.017) h, (0.803±0.046) and (2.233±0.410) h, (0.016±0) and (0.149±0.018) L·h⁻¹·kg⁻¹, (0.015±0.001) and (0.446±0.016) L·h⁻¹·kg⁻¹, (133.335±3.844) and (9.298±0.179) mg·h·L⁻¹, (143.851±3.595) and (14.464±1.451) mg·h·L⁻¹, (0.009±0.001) and (0.223±0.007) L·kg⁻¹, (0.006±0.001) and (0.212±0.032) L·kg⁻¹, respectively. The results showed that the established HPLC method was highly specific, and could be used for the simultaneous detection of aceglutamide and HSYA of Guhong injection in MCAO rats, which was conducive to pharmacokinetic studies. Pharmacokinetic data and parameters could provide reference for continuous administration and interval administration of the drug.
RESUMO
H9 subtype avian influenza virus (AIV) and infectious bronchitis virus (IBV) are major pathogens circulating in poultry and have resulted in great economic losses due to respiratory disease and reduced egg production. As similar symptoms are elicited by the two pathogens, it is difficult for their differential diagnosis. So far, no reverse transcription-polymerase chain reaction (RT-PCR) assay has been found to differentiate between H9 AIV and IBV in one reaction. Therefore, developing a sensitive and specific method is of importance to simultaneously detect and differentiate H9 AIV and IBV. In this study, a duplex RT-PCR (dRT-PCR) was established. Two primer sets target the hemagglutinin (HA) gene of H9 AIV and the nucleocapsid (N) gene of IBV, respectively. Specific PCR products were obtained from all tested H9 AIVs and IBVs belonging to the major clades circulating in China, but not from AIVs of other subtypes or other infectious avian viruses. The sensitivity of the dRT-PCR assay corresponding to H9 AIV, IBV and mixture of H9 AIV and IBV were at a concentration of 1×101, 1.5×101 and 1.5×101 50% egg infective doses (EID50) mL-1, respectively. The concordance rates between the dRT-PCR and virus isolation were 99.1 and 98.2%, respectively, for detection of samples from H9N2 AIV or IBV infected chickens, while the concordance rate was 99.1% for detection of samples from H9N2 AIV and IBV co-infected chickens. Thus, the dRT-PCR assay reported herein is specific and sensitive, and suitable for the differential diagnosis of clinical infections and surveillance of H9 AIVs and IBVs.
