OBJECTIVE: Patients with nasopharyngeal carcinoma experience highly variable outcomes despite receiving similar therapeutic regimens. Identifying biomarkers that predict survival and guide individualized therapy is urgently needed. Cystatin C has been explored as a valuable prognostic marker in several malignancies. We retrospectively assessed the relationship between serum cystatin C levels and nasopharyngeal carcinoma prognosis in a large cohort of nasopharyngeal carcinoma patients receiving long-term follow-up. METHODS: A total of 1063 consecutive patients diagnosed with nasopharyngeal carcinoma from June 2006 to December 2010 were retrospectively analyzed. The serum levels of cystatin C at the time of diagnosis were collected. Receiver operating characteristic curve analysis, the Kaplan-Meier method and multivariate analyses using a Cox regression model were performed to assess the correlation of cystatin C levels with overall survival, progression-free survival, distant metastasis-free survival and loco-regional recurrence-free survival. RESULTS: The median follow-up duration was 68.3 months. The optimal cut-off value of cystatin C levels for predicting death was 0.945 mg/L. Compared with the low cystatin C group, the high cystatin C group experienced significantly shorter overall survival (hazard ratio=1.47, p=0.050), progression-free survival (hazard ratio=1.65, p=0.004), distant metastasis-free survival (hazard ratio=2.37, p<0.001) and loco-regional recurrence-free survival (hazard ratio=2.40, p=0.002). Based on multivariate analysis, a high cystatin C level was identified as a significant and independent negative predictor of overall survival (hazard ratio=1.47, p=0.050), progression-free survival (hazard ratio=1.65, p=0.004), distant metastasis-free survival (hazard ratio=2.37, p<0.001), and loco-regional recurrence-free survival (hazard ratio=2.40, p=0.002). CONCLUSION: Cystatin C levels are associated with the prognosis of nasopharyngeal carcinoma patients. A high cystatin C level is an independent indicator of poor prognosis for nasopharyngeal carcinoma patients.

AbstractBackground BmK I, a site-3-specific modulator of voltage-gated sodium channels (VGSCs), causes pain and hyperalgesia in rats, while BmK IT2, a site-4-specific modulator of VGSCs, suppresses pain-related responses. A stronger pain-related effect has been previously attributed to Buthus martensi Karsch (BmK) venom, which points out the joint pharmacological effect in the crude venom.Methods In order to detect the joint effect of BmK I and BmK IT2 on ND7-23 cells, the membrane current was measured by whole cell recording. BmK I and BmK IT2 were applied successively and jointly, and the synergistic modulations of VGSCs on ND7-23 cells were detected.Results Larger peak I Na and more negative half-activation voltage were elicited by joint application of BmK I and BmK IT2 than by application of BmK I or BmK IT2 alone. Compared to the control, co-applied BmK I and BmK IT2 also significantly prolonged the time constant of inactivation.Conclusions Our results indicated that site-4 toxin (BmK IT2) could enhance the pharmacological effect induced by site-3 toxin (BmK I), suggesting a stronger effect elicited by both toxins that alone usually exhibit opposite pharmacological effects, which is related to the allosteric interaction between receptor site 3 and site 4. Meanwhile, these results may bring a novel perspective for exploring the underlying mechanisms of scorpion sting-induced pain.

Gas phase heats of formation (HOF) of 18 kinds of 390 organic compounds were calculated by quantum chemical calculation using semi-empirical PM3, PDDG and PM6 methods. The calculated HOFs were compared with the experimental data to illustrate the accuracy for different kinds of organics. Furthermore, the calculated values were linearly fitted with experimental values using the least square method, and were afterward substituted into the fitted regression equations to obtain the calibrated ones. The results show that, for 10 kinds of the selected organics, PM6 is more accurate, and PDDG is more accurate for 7 kinds of organics, while PM3 is only good for amino acid. As a whole, PM6 predicts the HOFs more accurately, with its weighted total mean average deviation (WTMAD) being 0.4 kJ/mol and 2.4 kJ/mol smaller than those of PM3 and PDDG, respectively. On the other hand, our results show that PDDG is the best to differentiate the isomers, with its mean average deviation (MAD) for isomerization energy being 7.8 kJ/mol and 11.0 kJ/mol smaller than PM6 and PM3, respectively. After the calibration, the values of MADs from the PM3, PDDG and PM6 results for most organics are reduced by 0.1 to 18.2 kJ/mol, with exceptions of the PM3 for amines, PDDG for carboxylic acids, and PM6 for ethers.

Se calcularon los calores de formación en fase gaseosa (HOF) de 390 compuestos orgánicos agrupados en 18 familias de compuestos con química cuántica, utilizando los métodos semiempíricos PM3, PDDG y PM6. Los valores calculados de HOFs fueron comparados con los valores experimentales correspondientes, con el fin de evaluar la precisión de los métodos para describir cada una de las diferentes familias de compuestos. Para esto, los valores calculados y experimentales de HOF fueron ajustados a una línea recta por el método de mínimos cuadrados, las ecuaciones de ajuste fueron utilizadas como curvas de calibración. Estas curvas muestran que para 10 familias de compuestos, el método PM6 es el mejor; mientras que el PDDG es mejor para 7 familias de compuestos orgánicos y, el PM3 es bueno sólo para los aminoácidos. De manera general, el método PM6 predice con mejor aproximación los valores de HOF con un desviación media promedio (WTMAD) de 0.4 kJ/mol, un valor 2.4 kJ/mol menor que el que presentan los métodos PM3 y PDDG. Por otra parte, se muestra que el PDDG es el mejor método para diferenciar los isómeros, con un desviación media promedio (MAD) más pequeña para la energía de isomerización en 7.8 kJ/mol y 11.0 kJ/mol, con respecto a PM3 and PDDG, respectivamente. A través de la calibración, los valores de MADs obtenidos para PM3, PDDG y PM6 para la mayoría de los compuestos estudiados disminuyeron de 0.1 a 18.2 kJ/mol, con excepción para el PM3 de las aminas, PDDG para los ácidos carboxílicos y el PM6 para los éteres.

Three fully optimized structures of 3,6-diamino-1,2,4,5-tetrazine-1,4-dioxide (LAX-112) dimers have been obtained with the density functional theory (DFT) method at the B3LYP/6-311++G level. Vibrational frequency calculations were carried out to ascertain that each structure is a minimum (no imaginary frequencies). The intermolecular interaction energy is calculated with the basis set superposition error (BSSE) correction and zero point energy (ZPE) correction. The greatest corrected binding energy among the three dimers is -42.38 kJ mol-1. The charge redistribution mainly occurs on the adjacent O(N)......H atoms between submolecules and the charge transfer between two subsystems is very small. Natural bond orbital (NBO) analysis was performed to reveal the origin of the interaction. Based on the vibrational analysis, the standard thermodynamic functions (heat capacities (cºp), entropies (S°m) and enthalpies (H°m)) and the changes of thermodynamic properties from the monomer to dimer with the temperature ranging from 200.00 K to 800.00 K have been obtained using statistical thermodynamics. The results show that the strong hydrogen bonds dominantly contribute to the dimers, while the bonding energies are not only determined by the hydrogen bonding. The dimerization process of dimer II can occur spontaneously at room temperature.

N-benzoyl-3,3-dinitroazetidine(BDNAZ) is a derivative of 3,3-dinitroazetidine (DNAZ). Its thermal behaviour was studied by DSC methods. The results show that there are one melting process and two exothermic decomposition processes. The kinetic parameters of the intense exothermic decomposition process were obtained from the analysis of the DSC curves. The apparent activation energy, pre-exponential factor and the mechanism function are 170.77 kJ mol-1,10(14.12) s-1 and f(α) = (1-a)-1/2, respectively. The specific heat capacity of BDNAZ was determined with a continuous Cp mode of a micro-calorimeter. The standard mole specific heat capacity of BDNAZ was 286.31 J mol¹ K-1 at 298.15 K. Using the relationship between Cp and T with the thermal decomposition parameters, the time of the thermal decomposition from initialization to thermal explosion (adiabatic time-to-explosion, tTIAD), the self-accelerating decomposition temperature (TSADT), thermal ignition temperature (T TIT), critical temperatures of thermal explosion (Tb) and period of validity (t0.9) were obtained to evaluate its thermal safety. The detonation velocity (D) and pressure (P) of BDNAZ were estimated by using the nitrogen equivalent equation according to the experimental density.