Objective To explore the feasibility of adding a flexible linker between two-pore-domain potassium channel TREK-1 (TWIK related K + channel 1)monomers to construct a tandem-linked dimer.Methods PCR was used to add a flexible linker between the two TREK-1 monomers.The cRNA obtained from in vitro transcription using the above vector was injected into Xenopus oocytes.After 24 -48 h,currents were recorded from these oocytes using a two-electrode voltage clamp.The effects of extracellular Ba2 + and pH on TdTREK-1 were observed and compared with those of native dimeric TREK-1.Results The tandem-linked dimeric TdTREK-1 was highly expressed in Xenopus oocytes.The currents through these channels were inhibited by extracellular Ba2 +and acidification.Furthermore,the responsiveness of the concatenated dimers to these extracellular stimuli was similar to that of native dimers.Conclusion Adding a flexible linker between the two monomers to construct the tandem-linked dimer does not affect the expression and gating properties of TREK-1, suggesting that the method be feasible.Such a method will allow the manipulation of a single subunit,which will help basis study the structure and function of TREK-1.

Objective To investigate the correlation between NRAMP1 gene polymorphisms and susceptibility to tuberculosis ( TB) in Tibetan people in Qinghai. Methods A case-control study was con-ducted in this study, involving 99 Tibetan patients with TB and 89 healthy Tibetans. The single nucleotide polymorphisms of NRAMP1 gene at rs17235409 and rs3731865 sites were detected by using TaqMan probe method. Gene cloning and sequencing typing were performed to analyze the single nucleotide polymorphisms of NRAMP1 gene at the rs17235416 site. SPASS20. 0 software was used to statistically analyze the correla-tion between NRAMP1 gene polymorphisms and susceptibility to TB in Tibetan people. Results No signifi-cant difference in the genotype frequencies of rs3731865 and rs17235409 was found between the two groups (χ2=0. 852, P=0. 356;χ2=0. 279, P=0. 597). The genotype frequencies of TGTG/TGTG and TGTG/del+del/del at the rs17235416 site were 70. 7% ( 70/99 ) and 29. 3% ( 29/99 ) in patients with TB and 86. 5% (77/89) and 13. 5% (12/89) in healthy subjects. There were significant differences in the geno-type frequencies of TGTG/TGTG and TGTG/del+del/del between the two groups (χ2=6. 870, P=0. 009). The genotypes of TGTG/del and del/del at rs17235416 were risk factors for TB ( OR=0. 376; 95%CI:0. 178-1. 794 as compared with the TGTG/TGTG genotype in Tibetan people in Qinghai. Conclusion This study suggested that the NRAMP1 gene polymorphisms at rs3731865 and rs1723409 sites had no correlation with the susceptibility to TB in Tibetans in Qinghai. However, the NRAMP1 gene polymorphisms at rs17235416 site were correlated with the susceptibility to TB. The TGTG/del alleles at the rs17235416 site might be the risk factors for tuberculosis in Tibetans in Qinghai.

Objective To evaluate the efficacy and safety of domestic palonosetron hydrochlo-ride injection on its prevention of postoperative nausea and vomiting.Methods A multi-centered,ran-domized,double-blinded and placebo-controlled clinical trial was carried out.A total of 281 patients were enrolled,with 141 of patients in study group and 140 of patients in control group respectively. 0.075 mg of intravenous palonosetron hydrochloride injection was delivered in the study group before anesthesia induction.The drug was substituted by 1.5 ml of NS in the control group.All anesthesia inductions were conducted by the intravenous injection of propofol,fentanyl and rocuronium,and were maintained with sevoflurane and fentanyl.Complete remission rate and treatment failure cut-off time of vomiting were evaluated at 0-6 h,6-72 h,0-72 h postoperatively.Results In the study group CR% 0-6 h,6-72 h and 0-72 h were 107 (75.89%),104 (73.76%)and 92 (65.25%),the control group was 81 (57.86%),70 (50%)and 62 (42.86%),CR% of the study group was significantly higher than that of the control group (P <0.01).Insignificant statistical difference but significant clin-ical difference exists in their treatment failure cut-off time,386.5 min and 300.0 min,respectively be-tween the groups.Conclusion Domestic palonosetron hydrochloride injection is safe and effective in the prevention of postoperative nausea and vomiting.

Background Macrophages are essential components of the natural immune system. They play a significant role in resisting foreign bodies in the respiratory tract and maintaining the homeostasis of the internal environment of lung tissue. Objective To investigate the mechanism of macrophage pyroptosis induced by silica dust with different particle sizes. Methods The modified murine macrophage cell line, RAW-ASC cells, was cultured and divided into a blank control group, a lipopolysaccharide (LPS) group (1 μg·mL⁻¹ LPS), a nano-SiO₂ group (1 μg·mL⁻¹ LPS+100 μg·mL⁻¹ nano-SiO₂), a micro-SiO₂ group (1 μg·mL⁻¹ LPS+750 μg·mL⁻¹ micro-SiO₂), and a positive control group [1 μg·mL⁻¹ LPS+3 mmol·L⁻¹ adenosine triphosphate (ATP)]. Apart from the blank control group, cells in other groups were pretreated with LPS for 6 h, and then exposed to SiO₂ or ATP for 4 h. According to the molecular target NOD-like receptor pyrin domain-containing protein 3 (NLRP3) and reactive oxygen species (ROS), we applied MCC950 (NLRP3 inhibitor) and N-acetyl cysteine (NAC, ROS scavenger) to macrophages. CCK-8 assay was used to detect cell viability; 5-ethynyl-2'-deoxyuridine (EdU) staining was used to detect cell proliferation; lactate dehydrogenase (LDH) assay kit was used to detect LDH in supernatant; calcein AM/PI fluorescent double-staining was applied to evaluate cell rupture; 2',7'-dichlorofluorescin diacetate (DCFH-DA) fluorescent probe was used to measure the content of ROS; Western blotting was used to measure the expressions of NLRP3, apoptosis-associated speck-like protein containing CARD (ASC), Caspase-1, gasdermin D (GSDMD), and interleukin-1β (IL-1β). Results Compared with the blank group, 100 μg·mL^-1nano-SiO₂ and 750 μg·mL^-1micro-SiO₂ dust exposure reduced the cell viability to 40% and 68% (P<0.05), and the cell proliferation rate to 30% and 33% (P<0.01), respectively; they also induced cell lysis and ROS release, upregulated NLRP3, ASC, Caspase-1, GSDMD, and IL-1β at protein level (P<0.05), and induced macrophage pyroptosis. After intervening with MCC950 (10 μmol·L^-1) and NAC (10 mmol·L^-1), the expressions of NLRP3, ASC, Caspase-1, and IL-1β decreased (P<0.05), and, specifically, NAC effectively reduced ROS levels (P<0.05). Conclusion Both nano- and micro-SiO₂ dust have cytotoxicity, can upregulate ROS level, activate NLRP3 inflammasome, and promote the release of cytokines, leading to pyroptosis. These results are helpful to reveal the molecular mechanism of macrophage pyroptosis induced by SiO₂ dust.