RESUMO
Purpose: To evaluate preoperative diffusion kurtosis imaging (DKI) in predicting the outcomes of large hepatocellular carcinoma (HCC) after liver resection (LR). Materials and methods: From January 2015 to December 2017, patients with a large (≥5cm) HCC who underwent preoperative DKI were retrospectively reviewed. The correlations of the mean kurtosis (MK), mean diffusivity (MD), and apparent diffusion coefficient (ADC) with microvascular invasion (MVI) or histological grade were analyzed. Cox regression analyses were performed to identify the predictors of recurrence-free survival (RFS) and overall survival (OS). A nomogram to predict RFS was established. P<0.05 was considered as statistically significant. Results: A total of 97 patients (59 males and 38 females, 56.0 ± 10.9 years) were included in this study. The MK, MD, and ADC values were correlated with MVI or histological grade (P<0.01). With a median follow-up time of 41.2 months (range 12-69 months), 67 patients (69.1%) experienced recurrence and 41 patients (42.3%) were still alive. The median RFS and OS periods after LR were 29 and 45 months, respectively. The 1-, 3-, and 5-year RFS and OS rates were 88.7%, 41.2%, and 21.7% and 99.0%, 68.3%, and 25.6%, respectively. MK (P<0.001), PVT (P<0.001), and ADC (P=0.033) were identified as independent predictor factors for RFS. A nomogram including the MK value for RFS showed the best performance, and the C-index was 0.895. Conclusion: The MK value obtained from DKI is a potential predictive factor for recurrence and poor survival, which could provide valuable information for guiding the efficacy of LR in patients with large HCC.
RESUMO
Calcineurin (CN) is a Ca(2+)/calmodulin(CaM)-dependent serine/threonine protein phosphatase which is a heterodimer composed of a 61 kDa catalytic subunit (CNA) and a 19 kDa regulatory subunit (CNB). The enzyme is critical for several important intracellular signal-transducing pathways, including T-cell activation. Its crystal structure reveals that the C-terminal of CNB lies in close vicinity of the N-terminal of CNA and each end has a long arm not involved in the active site. After fusing two subunits, it was determined that folding and function of the protein were not affected by the fusion. We amplified a fused gene of A and B subunits using a pair of linker primers including six codons of glycine. A single chain calcineurin was constructed and purified to near-homogeneity. The recombinant enzyme was fully soluble, displayed high specific activity with substrate, and exhibited biochemical properties and kinetic parameters similar to those of the native enzyme from the bovine brain. It was still activated by Ca(2+)/calmodulin but was not regulated by extra CNB and was still strongly stimulated by Mn(2+) and Ni(2+) divalent metal ions. The solution conformations of both recombinant enzyme and bovine calcineurin were assayed under the same conditions using intrinsic fluorescence spectroscopy and circular dichroism spectropolarimetry, and results showed their graphs are approximately identical. Our findings suggested that the fusion of A and B subunits of calcineurin does not affect their folding pathways and structural changes involved in their function, furthermore, they are bound to the correct binding site.
