Effect of exogenous hydrogen sulfide in the nucleus tractus solitarius on gastric motility in rats

BACKGROUND Hydrogen sulfide(H2S)is a recently discovered gaseous neurotransmitter in the nervous and gastrointestinal systems.It exerts its effects through multiple signaling pathways,impacting various physiological activities.The nucleus tractus solitarius(NTS),a vital nucleus involved in visceral sensation,was investigated in this study to understand the role of H2S in regulating gastric function in rats.AIM To examine whether H2S affects the nuclear factor kappa-B(NF-κB)and transient receptor potential vanilloid 1 pathways and the neurokinin 1(NK1)receptor in the NTS.METHODS Immunohistochemical and fluorescent double-labeling techniques were employed to identify cystathionine beta-synthase(CBS)and c-Fos co-expressed positive neurons in the NTS during rat stress.Gastric motility curves were recorded by inserting a pressure-sensing balloon into the pylorus through the stomach fundus.Changes in gastric motility were observed before and after injecting different doses of NaHS(4 nmol and 8 nmol),physiological saline,Capsazepine(4 nmol)+NaHS(4 nmol),pyrrolidine dithiocarbamate(PDTC,4 nmol)+NaHS(4 nmol),and L703606(4 nmol)+NaHS(4 nmol).RESULTS We identified a significant increase in the co-expression of c-Fos and CBS positive neurons in the NTS after 1 h and 3 h of restraint water-immersion stress compared to the expressions observed in the control group.Intra-NTS injection of NaHS at different doses significantly inhibited gastric motility in rats(P<0.01).However,injection of saline,first injection NF-κB inhibitor PDTC or transient receptor potential vanilloid 1(TRPV1)antagonist Capsazepine or NK1 receptor blockers L703606 and then injection NaHS did not produce significant changes(P>0.05).CONCLUSION NTS contains neurons co-expressing CBS and c-Fos,and the injection of NaHS into the NTS can suppress gastric motility in rats.This effect may be mediated by activating TRPV1 and NK1 receptors via the NF-κB channel.

Inhibition of LOX-1 alleviates the proinflammatory effects of high-mobility group box 1 in Aspergillus fumigatus keratitis

AIM: To investigate the inflammatory amplification effect of high-mobility group box 1(HMGB1) in Aspergillus fumigatus(A. fumigatus) keratitis and the relationship between lectin-like oxidized low-density lipoprotein receptor 1(LOX-1) and HMGB1 in keratitis immune responses.METHODS: Phosphate buffer saline(PBS), and Boxb were injected into BALB/c mice subconjunctivally before the corneas were infected with A. fumigatus. RAW264.7 macrophages and neutrophils were pretreated with PBS and Boxb to determine the HMGB1 inflammatory amplification effects. Abdominal cavity extracted macrophages were pretreated with Boxb and Poly(I)(a LOX-1 inhibitor) before A. fumigatus hyphae stimulation to prove the the relationship between the two molecules. LOX-1, interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), macrophage inflammatory protein-2(MIP-2) and IL-10 were assessed by polymerase chain reaction and Western blot.RESULTS: Pretreatment with Boxb exacerbated corneal inflammation. In macrophages and neutrophils, A. fumigatus induced LOX-1, IL-1β, TNF-α and MIP-2 expression in Boxb group was higher than those in PBS group. Poly(I) treatments before infection alleviated the proinflammatory effects of Boxb in abdominal cavity extracted macrophages. Pretreatment with Boxb did not influence Dectin-1 mRNA levels in macrophages and neutrophils.CONCLUSION: In fungal keratitis, HMGB1 is a proinflammatory factor in the first line of immune response. HMGB1 mainly stimulates neutrophils and macrophages to produce inflammatory cytokines and chemokines during the immune response. LOX-1 participates in HMGB1 induced inflammatory exacerbation in A. fumigatus keratitis.

溪黄草黄酮对肝癌细胞增殖,迁移和侵袭的影响及相关机制

目的探讨溪黄草黄酮[Flavonoids from Rabdosia serra(Maxim.)Hara]对人肝癌细胞株Hep G2的增殖、迁移与侵袭能力的影响,并研究初步机制.方法 CCK-8法检测不同浓度溪黄草黄酮(0、1、5、10、20和40μmol/L)对Hep G2细胞活性的影响;划痕实验和Transwell侵袭实验分别检测细胞的迁移和侵袭能力;Western blot检测Notch-1,Cyclin D1,MMP-2和MMP-9蛋白表达水平变化.结果 CCK-8法检测结果显示溪黄草黄酮呈浓度依赖性抑制Hep G2细胞的生长,当浓度到达20μmol/L时,抑制作用达到最大;经溪黄草黄酮干预后,Hep G2细胞迁移和侵袭能力显著下降,Notch-1,Cyclin D1,MMP-2和MMP-9蛋白表达水平显著下降.结论溪黄草黄酮具有抑制肝癌细胞株Hep G2增殖、迁移和侵袭的作用,其作用机制可能与溪黄草黄酮抑制Notch-1-MMP-2/-9和Notch-1-Cyclin D1信号通路相关.

Numerical simulation on fluid flow behavior during 3-dimensional dendrite growth with random preference angle

The flow behavior of three-dimensional(3D)dendrite growth with random preferred angle under natural convection was studied by using the Lattice Boltzmann-Cellular Automata(LB-CA)method with dynamic and static grids.In this model,the temperature field,flow field and solute field calculated by Lattice Boltzmann method(LBM)and dendrite growth calculated by CA method were carried out in static and dynamic grids respectively,and the coupling between LBM and CA was performed by interpolation of calculation parameters between dynamic and static grids.Results show that the asymmetry of solid phase distribution makes the streamline distribution more complex.At the initial stage of multiple dendrites growth,the fluid flow is relatively free.When dendrites grow close to each other,the fluid flow is blocked and can only flow along the gap between dendrites.During the wall equiaxed-columnar-central equiaxed crystals transformation(ECET)process,dense eddy current is formed at the wall equiaxed crystals at first.Then,when the wall equiaxed crystals gradually develop into columnar crystals,the eddy current moves with the solid-liquid interface.When the central equiaxed crystals are formed,the eddy current at the front of the columnar crystals gradually disappears.New eddies appear as the central equiaxed crystal grows.

Disparate expression of autophagy in corneas of C57BL/6 mice and BALB/c mice after Aspergillus fumigatus infection

AIM: To determine the disparate expression of autophagy in the Aspergillus fumigatus(A. fumigatus) keratitis between susceptible C57 BL/6 mice and resistant BALB/c mice.METHODS: C57 BL/6 and BALB/c mice were used to establish fungal keratitis models. Disease severity and inflammatory response were observed by slit lamp microscopy in A. fumigatus-infected corneas of C57 BL/6 and BALB/c mice at 1, 3 and 5 d. Hematoxylin-eosin(H&E) staining was used to detect pathological changes of corneas. The expression of autophagy-related proteins Beclin-1, LC3, SQSTM1/p62, and LAMP-1 was assessed by Western blot in C57 BL/6 and BALB/c mice at 1, 3 and 5 d post infection(p.i.). Immunofluorescent staining was used to test the expression of LC3 in corneas after A. fumigatus infection.RESULTS: Keratitis severity was higher in C57 BL/6 mice versus BALB/c mice at 1, 3 and 5 d p.i. H&E staining showed that the number of inflammatory cells was larger and the severity of ulcer was higher in C57 BL/6 mice than in BALB/c mice after stimulation with A. fumigatus. Higher expression of LAMP-1, Beclin-1, and LC3 was shown in C57 BL/6 mice corneas than in BALB/c mice corneas at 1, 3 and 5 d p.i., while the expression of p62 was lower in C57 BL/6 mice. The fluorescence of LC3 was significantly increased in corneas of C57 BL/6 mice compared with BALB/c mice after A. fumigatus infection.CONCLUSION: The expression of autophagy is higher in corneas of C57 BL/6 mice than in BALB/c mice afterA. fumigatus infection. Autophagy may be positively correlated with keratitis severity and pathological changes.

供水管路中驼峰气阻的临界平衡实验研究(英文)

目的:输水管道的驼峰气阻是指由于管路高峰位置的滞气作用使气体不断聚积在峰顶附近、产生的气体阻碍水流的局部水力现象。它能够导致管路过水断面减小、输水能耗增加、输送效率降低和管路压力振荡等后果,严重威胁海底管道输水的稳定性和安全性。本文旨在分析滞留气团在供水管道中的力学平衡、能量损失、移动和溢出机理,研究水流流速对气团的推移特性,提出预测和消除驼峰气阻的方法,使输水管道免受驼峰气阻的危害,提高输水管道的供水效率。创新点:1.设计了具有连续坡角变化的圆弧形驼峰管道实验,该实验可以定量模拟气团体积和平衡角度;2.建立了驼峰气阻的水头损失经验公式和恒定流情况下驼峰气阻的管道坡角和流速的对应关系式,可用于预测和消除驼峰气阻的危害。方法:1.通过驼峰气团的受力特性分析,获得满足量纲和谐的力学平衡方程;2.采用试验观察和测试获得有无气泡情况下的水头损失和平衡状态下的坡角,通过等价球体方法对测试数据进行无量纲拟合,获得气阻的水头损失方程系数,并通过流速和平衡坡角建立恒定流情况下的临界平衡方程;3.基于试验拟合获得临界平衡方程,建立预测和评估气阻的准则系数,并提出消除气阻的水流临界流速。结论:1.当管路流速较小时,供水管路的驼峰顶端可能滞留和聚集气体,形成驼峰气阻;气体体积越大对水流阻碍越明显,可能造成的水头损失也越大;2.利用等价球体法可以极大地简化驼峰气阻的形状,并良好地模拟气阻的平衡特性和阻力特性;3.管道流速是影响驼峰气阻临界平衡位置的最重要因素,通过减小管道起伏的坡角或增加水流流速可以防止和消除驼峰气阻的危害。