Anti-tumor effects of CIK combined with oxaliplatin in human oxaliplatin-resistant gastric cancer cells in vivo and in vitro

<p>Abstract</p> <p>Background</p> <p>Drug resistance remains a great challenge in the treatment of gastric cancer. The goal of this study was to explore the anti-tumor effects and mechanism of cytokine-induced killer (CIK) cell combined with oxaliplatin (L-OHP) in human oxaliplatin-resistant gastric cancer cells.</p> <p>Methods</p> <p>After producing oxaliplatin-resistant gastric cancer cells, cell morphology, growth and doubling time were observed, followed by detection of cell cycle distribution and apoptosis, drug sensitivity (e.g., L-OHP) and expression of P-gp and livin. MTT assay, in vivo pharmacodynamics and pathomorphology experiments were used to detect killing activities of CIK combined with L-OHP.</p> <p>Results</p> <p>Compared with parental gastric cancer cells, oxaliplatin-resistant gastric cancer cells in S phase were reduced and cell apoptosis rate was increased (P < 0.05), the inhibition rate of 10 chemotherapeutics on oxaliplatin-resistant gastric cancer cells was significantly lower and the expression of P-gp was significantly higher (P < 0.05). However, there was no significant difference in livin expression between parental gastric cancer cells and oxaliplatin-resistant gastric cancer cells (P > 0.05). The in vitro killing activity of CIK combined with L-OHP on parental cells and oxaliplatin-resistant cells were significantly enhanced compared with L-OHP or CIK alone. And it showed greater synergetic effects against oxaliplatin-resistant cells compared with parental cells (P < 0.05). In addition, survival rate, abdominal circumference and pathomorphology results revealed stronger in vivo anti-tumor effects when the two therapies were combined.</p> <p>Conclusions</p> <p>The mechanism of oxaliplatin-resistant cell secondary multidrug resistance was correlated with the variation of cell cycle distribution, extension of doubling time and upregulation of P-gp expression. The synergistic effect of CIK in combination with L-OHP on killing activity against oxaliplatin-resistant cells was shown in vivo and in vitro.</p

The safety and efficacy of carbon nanoparticle suspension injection versus indocyanine green tracer-guided lymph node dissection during radical gastrectomy (FUTURE-01): A single-center randomized controlled trial protocol

BackgroundThe use of lymph node (LN) tracers can help obtain a complete dissection of the lymph nodes and increase the detection rate of LNs and metastatic LNs. Carbon nanoparticle suspension injection (CNSI) and indocyanine green (ICG) have been widely used in radical gastrectomy in recent years. Nevertheless, the comparison of their clinical effects has not been studied.Method/designThe FUTURE-01 trial will be the first randomized, open-label, single-center trial to compare CNSI and ICG. The study started in 2021 and enrolled 96 patients according to a prior sample size calculation. The primary outcome is the number of LNs retrieved. The secondary outcomes are LN staining rate, LN metastasis rate, stained LN metastasis rate, perioperative recovery and survival.ConclusionBy comparing the safety and efficacy of CNSI and ICG tracer-guided LN dissection in patients with gastric cancer, we can determine the most appropriate LN tracer at present. With the help of LN tracers, the operation is simplified, and the prognosis of these patients is improved. Our study is a prospective exploration of the safety, efficacy, and prognosis of CNSI and ICG.Clinical trial registrationhttps://clinicaltrials.gov/ct2/show/NCT05229874?cond=NCT05229874&amp;draw=2&amp;rank=1, identifier NCT05229874

Cellular instabilities of n-butane/air flat flames probing by PLIF-OH and PLIF-CH2O laser diagnosis

The structure and instability characteristics of non-adiabatic fuel-rich n-butane/air cellular flames on McKenna burner were experimentally investigated at atmospheric pressure. Planar Laser Induced Fluorescence (PLIF-OH and PLIF-CH2O) flame diagnosis technology was utilized to probe the flame structure under varied equivalence ratio and inflow mixture velocity respectively. Results show that, the equivalence ratio plays an important role in forming cellular flames. The flat, wrinkled and cellular flames appear in turn when increasing equivalence ratio and inflow velocity. Differed to the separated cells of cellular flames appeared in direct Digital camera images and PLIF-OH images, the PLIF-CH2O images clearly display that all cellular flames are connected. In the PLIF-OH images of cellular flames, the OH radical fluorescence signal intensity is higher in the convex region toward unburned mixture than in the concave region, but in PLIF-CH2O images, the fluorescence signal intensity is nearly unchanged in both convex and concave regions. Quantitative stand-off distance and amplitude data probed by PLIF-OH and PLIF-CH2O diagnosis together reveal that the onset of non-adiabatic n-butane/air cellular flames on flat flame burner is dominantly governed by diffusive-thermal mechanism

A skeletal n-butane mechanism with integrated simplification method

A new skeletal mechanism of n-butane is developed for describing its ignition and combustion characteristics applicable over a wide range of conditions: initial temperature 690-1430 K, pressure 1-30 atm, and equivalence ratio 0.5-2.0. Starting with a detailed chemical reaction kinetic model of 230 species and 1328 reactions (Healy et al., Combust. Flame, 2010), the directed relation graph method is applied as the first step to derive a semi-detailed mechanism with 134 species. Then, the reaction path analysis in conjunction with temperature sensitivity analysis is used to remove the redundant species and reaction paths simultaneously under the condition of low-temperature and moderate-to-high temperatures, respectively. Finally, a skeletal n-butane mechanism consisting of 86 species and 373 reactions can be obtained. Mechanism validation indicates that the new developed skeletal mechanism is in good agreement with the detailed mechanism in predicting the global ignition and combustion characteristics. The new skeletal mechanism is further validated using extensive available literature data including rapid pressure machine ignition delay time, shock-tube ignition delay time, laminar flame speed, and jet-stirred reaction oxidation, covering a large range of temperatures, pressures, and equivalence ratios. The comparison results demonstrate that a satisfactory agreement between predictions and experimental measurements is achieved. (C) 2020 Energy Institute. Published by Elsevier Ltd. All rights reserved

Interactions between the flame and different coatings in a slit burner

To improve the lifetime and the flame stability of combustion-based micro devices, two coating materials (AlCrN and alumina) are deposited on STS 304 substrate to investigate the interactions between the premixed n-butane/air flame and the solid walls heated to different temperatures in a slit burner. The flame-wall interaction is characterized by the measurements of quenching distance, flame pulsation and OH intensity distribution. Results show that the alumina coating sustains a shorter quenching distance compared with the STS 304 plate at an identical wall temperature, whereas the AlCrN coating exhibits a larger one. The highest near-wall OH intensity is observed in the alumina-coated wall, while the lowest is observed in the AlCrN-coated wall, indicating a correlation between the near-wall OH distribution and the quenching distance. When the channel gap is reduced to a critical value, the stable flame is converted into a pulsating flame, and the pulsation frequency monotonously increases as the wall temperature increases. Surface analysis reveals that the adsorbed oxygen on the surface may play an important role in flame quenching characteristics by affecting the OH intensity close to the wall surface. In addition, the flame exerts varying degrees of influence on the coating stability, surface structure, and elemental composition. The alumina coating maintains excellent thermal and chemical stability and can be used for surface optimization of static components. In contrast, although the AlCrN coating undergoes slight changes in structure and composition under the action of flame, it may still be a surface optimization option for moving parts without a significant increase in quenching distance

Enhancing the flame stability in a slot burner using yttrium-doped zirconia coating

Quenching experiments using a slot burner and surface analysis were conducted to analyze the effects of two materials (ZrO2 and 13.5 wt%Y2O3-doped ZrO2 (13.5YSZ)) deposited on stainless steel 304 (STS304) substrate on the flame stability of premixed methane/air mixtures of varying equivalence ratio and flow velocity at a wall temperature range of 373 K to 773 K. Results showed that these two types of coatings are beneficial for decreasing the quenching distance and extending the flame stability limit. Moreover, doping 13.5 wt%Y2O3 into ZrO2 coating was more conducive to reduce quenching data and broaden lower flammability limits in the fuel-lean side. Surface analyses reflected that the superior mobility of lattice oxygen for 13.5YSZ coating plays a crucial role in improving the quenching characteristics due to the formation of extrinsic active oxygen vacancies. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) verified that the methane oxidation process can be accelerated over the two coating surfaces due to the high catalytic performance. Finally, one migration route of oxygen ions consisting of the dynamic oxygen diffusion and replenishment pathways was proposed to discuss the underlying mechanism of flame stability improvement when using yttrium-stabilized zirconia composite coatings in a narrow channel

One zirconia-based ceramic coating strategy of combustion stabilization for fuel-rich flames in a small-scale burner

From the perspective of the thermal/chemical performance management of a slot burner, three kinds of blended coatings with the low thermal conductivity and certain chemical activities, including 30wt.%Y2O3/ZrO2, 30wt.% MgO/ZrO2 and 30wt.%Al2O3/ZrO2, were prepared on stainless steel walls plated by atmospheric plasma spraying. The effects of coating material, wall temperature, and equivalence ratio on fuel-rich methane flame characteristics were investigated experimentally. The OH planar laser-induced fluorescence (OH-PLIF) technique was used to obtain OH intensity and flame anchoring location. The physical and chemical properties of different coatings before and after spraying were analyzed by a series of material and surface characterization techniques. Results show that compared with pure ZrO2 coating, the quenching distances of three ZrO2-based blended coatings with Y2O3, MgO, and Al2O3 decrease to some extent, resulting in the minimum quenching distance of Al2O3/ZrO2 coating, and the maximum one for Y2O3/ZrO2 coating. Meanwhile, the blended coating walls result in the higher flame anchoring location than that of pure ZrO2 in most cases, in which the coating of Y2O3/ZrO2 displays the highest location. The blended coatings have higher thermal conductivity, which is beneficial to balance part of the heat loss through the axial heat recirculation of wall structures, and thus expanding stability limits at low temperatures. In addition, partial lattice solid solutions are formed in mixture systems after the ultra-high-temperature thermal spraying, leading to more surface lattice oxygen and stronger chemical promotion. In summary, reasonable allocation of ZrO2-based ceramic components as coating wall is an effective alternative strategy to control flame stabilization in small-scale combustion devices