Assessment of hepatic fat content in using quantitative ultrasound measurement of hepatic/renal ratio and hepatic echo-intensity attenuation rate.

AIMS: This study aims to evaluate and validate a simple quantitative ultrasound (US) method for determining the hepatic fat content (HFC) based on the combination of quantitative US hepatic/renal ratio (US-HRR) and quantitative US hepatic echo-intensity attenuation rate (US-HAR) as compared with [1H]-magnetic resonance spectroscopy (1H-MRS). MATERIAL AND METHODS: There were a total of 242 subjects recruited in the present study. All subjects were examined for HFC by quantitative US and 1H-MRS methods. The QUS-HRR and QUS-HAR were calculated from ordinary ultrasound images of liver and kidney with a triple modality 3D abdominal phantom using the Image J software. RESULTS: The results found that US-HRR and US-HAR correlated with 1H-MRS HFC (US-HRR: r=0.946, p<0.001; US-HAR: r=0.936, p<0.001). The equation for HFC prediction by using quantitative US was: HFC (%) = 28.965 × US-HRR + 218.045 × US-HAR - 8.892. Subgroup analysis in study subjects with body mass index (BMI) ≥28 showed that quantitative US HFC was associated with 1H-MRS HFC (R2=0.953, p<0.001). Receiver operating characteristic (ROC) analysis observed that the cut-off value of fatty liver diagnosis was 6.71% in using the quantitative US model; the sensitivity and specificity for fatty liver diagnosis were 94.15% and 96.30%, respectively. Variability analysis indicated that there was a relative high degree of consistency in the measurement of HFC with different operators or ultrasonic apparatus. CONCLUSIONS: Quantitative US measurement could be regarded as a simple, sensitive tool to accurately assess HFC. It provides a valid alternative to 1H-MRS as an easy, non-invasive option for the precise estimation of HFC in clinical practice.

Fitness costs of sulfoxaflor resistance in the cotton aphid, Aphis gossypii Glover.

Aphis gossypii Glover is an economically important pest of numerous crops throughout the world. Some field populations of A.gossypii in China have developed moderate level of resistance to sulfoxaflor, a newly released sulfoximine insecticide for management of sap-feeding pests. To evaluate the effect of sulfoxaflor resistance on the fitness cost of A. gossypii, the life history traits of sulfoxaflor-resistant strain (SulR) and an isogenic susceptible strain (SS) were compared using the age-stage, two-sex life table approach. The results showed that the resistant strain had a reduction in fitness (relative fitness = 0.917), along with significantly decreases in longevity, fecundity, net reproductive (R0), mean generation time (T) and gross reproductive rate (GRR). Compared to the susceptible strain, SulR strain showing a shorter developmental duration of each nymph instar stage. Moreover, the adult pre-oviposition period (APOP) and total preoviposition period (TPOP) of SulR strain were also significantly shorter than that of the susceptible strain. Investigation of six development and reproduction related genes indicated that EcR, USP and JHBP were overexpressed in the SulR strain, while the mRNA transcript level of Vg was decreased significantly compared to the susceptible strain. These results suggest that there is a fitness cost associated with sulfoxaflor resistance in A. gossypii and the different expression of EcR, USP, JHBP, and Vg may play very important role in this trade-off.