The Genomic Evolution and the Transmission Dynamics of H6N2 Avian Influenza A Viruses in Southern China

In China, the broad prevalence of H6 subtype influenza viruses, increasingly detected in aquatic birds, promotes their exchange materials with other highly pathogenic human-infecting H5N1, H5N6, and H7N9 influenza viruses. Strikingly, some H6 subtype viruses can infect pigs, dogs, and humans, posing risks to public health. In this study, 9 H6N2 viruses recovered from waterfowl species in the Guangdong province of China in 2018 were isolated and sequenced. Phylogenetic analysis revealed that the genome sequences of these H6N2 viruses belonged to Group I, except for the NP gene in Group III. Coalescent analyses demonstrated that the reassortment of NA and NS genes have occurred in two independent clusters, suggesting H6 subtype viruses had been undergoing a complex reassortant. To examine the evolutionary dynamics and the dissemination of the H6 subtype viruses, a Bayesian stochastic search variable selection was performed for results showing higher viral migration rates between closer provinces, including Guangdong, Jiangxi, Guangxi, and Fujian. Notably, the transmission routes of the H6 subtype viruses were concentrated in Jiangxi Province, the most frequent location for input and output transmission and a region containing Poyang Lake, a well-known wintering site for migration birds. We also found that the aquatic birds, especially ducks, were the most common input source of the viral transmission. In addition, we also found that eight positively selected amino acid sites were identified in HA protein. Given their continuous dissemination and the broad prevalence of the H6 subtype influenza viruses, continued surveillance is warranted in the future.     

Competing interactions give rise to two-state behavior and switch-like transitions in charge-rich intrinsically disordered proteins

The most commonly occurring intrinsically disordered proteins (IDPs) are polyampholytes, which are defined by the duality of low net charge per residue and high fractions of charged residues. Recent experiments have uncovered nuances regarding sequence–ensemble relationships of model polyampholytic IDPs. These include differences in conformational preferences for sequences with lysine vs. arginine and the suggestion that well-mixed sequences form a range of conformations, including globules, conformations with ensemble averages that are reminiscent of ideal chains, or self-avoiding walks. Here, we explain these observations by analyzing results from atomistic simulations. We find that polyampholytic IDPs generally sample two distinct stable states, namely, globules and self-avoiding walks. Globules are favored by electrostatic attractions between oppositely charged residues, whereas self-avoiding walks are favored by favorable free energies of hydration of charged residues. We find sequence-specific temperatures of bistability at which globules and self-avoiding walks can coexist. At these temperatures, ensemble averages over coexisting states give rise to statistics that resemble ideal chains without there being an actual counterbalancing of intrachain and chain-solvent interactions. At equivalent temperatures, arginine-rich sequences tilt the preference toward globular conformations whereas lysine-rich sequences tilt the preference toward self-avoiding walks. We also identify differences between aspartate- and glutamate-containing sequences, whereby the shorter aspartate side chain engenders preferences for metastable, necklace-like conformations. Finally, although segregation of oppositely charged residues within the linear sequence maintains the overall two-state behavior, compact states are highly favored by such systems.

Significant fractions of eukaryotic proteomes are made up of intrinsically disordered regions (IDRs) (1). Conformational heterogeneity (2) is a defining hallmark of IDRs (3–5). Studies over the past decade have helped quantify relationships (6) that connect sequence-encoded information within IDRs to properties of conformational ensembles such as overall sizes and shapes, the amplitudes of spontaneous conformational fluctuations, and the dynamics of interconverting between distinct conformational states (7–19). These sequence–ensemble relationships have direct functional consequences that have been uncovered via studies based on biophysical, biochemical, and engineering approaches (5, 20–38). Our work, which is focused on physical principles underlying sequence–ensemble relationships of IDRs, is of direct relevance to understanding how IDRs function.Charged residues are key determinants of sequence–ensemble relationships of IDRs (19, 39–41). They contribute through highly favorable free energies of hydration (42) and long-range electrostatic interactions. Net charge per residue (19, 39, 40) and the patterning of oppositely charged residues (43–45) are useful order parameters for describing sequence–ensemble relationships and interactions of charge-rich IDRs (46). Both features can be modulated through posttranslational modifications (47–51), charge renormalization by solution ions (52), and charge regulation through context- and conformation-dependent uptake and release of protons (53).Polyampholytes feature roughly equivalent numbers of oppositely charged residues, and they make up more than 70% of known IDRs (7, 17). For a given amino acid composition, which sets the fraction of charged residues and the net charge per residue, it has been shown that the linear mixing vs. segregation of oppositely charged residues can have a profound impact on sequence–ensemble relationships of polyampholytic IDRs (31, 32, 43). Specifically, for a given set of solution conditions, sequences featuring uniform linear distributions of oppositely charged residues are predicted to favor more expanded conformations compared to sequences with identical amino acid compositions where the oppositely charged residues are segregated into distinct blocks along the linear sequence. These predictions made using simulation and theory (43, 44, 54) have been confirmed using different experiments (31–33, 41, 55).The ensemble-averaged radii of gyration (R_g) of flexible polymers follow scaling relationships of the form R_g ∼ N^ν. Here, N denotes the number of residues and the scaling exponent ν is a measure of the length scale over which conformational fluctuations are correlated. For homopolymers or systems that are effective homopolymers, ν has four limiting values, viz., 0.33, 0.5, 0.59, or 1, corresponding to globules, Flory random coils (FRCs), self-avoiding walks, and rod-like conformations, respectively (56). Atomistic simulations performed at fixed temperatures suggest that ν ≈ 0.59 (43) for strong, well-mixed polyampholytes (17). The explanation for this behavior is as follows. Electrostatic attractions and repulsions are realized on similar length scales for well-mixed sequences. These interactions screen one another, and the highly favorable free energies of hydration become the main determinants of overall sizes and shapes of well-mixed strong polyampholytes (17). In contrast, compact conformations are formed by strong polyampholytes where oppositely charged residues are segregated into distinct blocks. Here, the electrostatic attractions between oppositely charged blocks can outcompete opposing effects of favorable solvation. These inferences were gleaned using sequences comprising 1:1 ratios of Lys and Glu (43). In the original simulations, the reference free energies of hydration of all charged residues were treated as being quantitatively equivalent and highly favorable. This leads to the hypothesis that Lys and Arg are interoperable with one another as determinants of sequence–ensemble relationships of IDRs (17). A similar inference emerges regarding the interoperability of Asp and Glu with respect to one another. The recent work of Sørensen and Kjaergaard has challenged these inferences (57). Using a system where model IDRs were deployed as flexible linkers between interaction domains, Sørensen and Kjaergaard used their measurements to estimate the relationships between amino acid sequence and the scaling exponent ν (57). Inferences from their experiments suggest that the ν ≈ 0.33 for (GRESRE)_n and ν ≈ 0.5 for (GKESKE)_n for the specific conditions they used in their measurements. Here, n is the number of repeats of the hexapeptides GRESRE or GKESKE. The results point to significant differences between Arg- and Lys-containing sequences. Further, while globularity of (GRESRE)_n has precedent in mean-field theories for polyampholytes, the mechanism by which FRC-like behavior of (GKESKE)_n is achieved is unclear. Here, we develop a plausible physical explanation for the findings of Sørensen and Kjaergaard (57). Our work is based on atomistic simulations and the ABSINTH implicit solvation model and forcefield paradigm (58–61).     

Construction of Smac gene-containing and human prostate specific antigen promoter-regulated vector and its expression

Objective: To construct an eukaryotic expression vector containing Smac gene and study the expression efficiency and specificity of prostate specific antigen(PSA) enhancer/promoter in a possible targeted gene therapy scheme for prostate cancer. Methods: PSA enhancer (PSAE) and promoter (PSAP) sequences were amplified using PCR method. CMV and T7 promoters were deleted from pcDNA3.1-Smac and replaced by the two specific fragments to generate pPSAE-PSAP-Smac. After transfection into different cell lines, the status of cells was observed. And then, we determined the relative concentration of Smac mRNA in RT-PCR. Results: The recombinant plasmid of pPSAE-PSAP-Smac was successfully constructed. And only the prostate cancer cell line PC-3 was suppressed after transfection with pPSAE-PSAP-Smac. However, other nonprostate lines were not. Moreover,the concentration of Smac mRNA regulated by PSA promoter and enhancer was higher in comparison to the CMV promoter-driven control vectors. Conclusion: An expression vector containing the Smac gene (based on elements of the PSA gene regulatory sequences) has been developed and shown to function in prostate cancer cell lines which provides a solid platform for launching clinical studies.     

PDCA在住院医师规范化培训师资教学查房督导中的应用

目的探讨PDCA循环在师资教学查房督导中运用成效,充分发挥督导作用,从而提升师资教学查房质量。方法将2019年师资作为对照组,采用旧的教学查房督导方法,2020年师资作为实验组,在教学查房督导中采取PDCA循环,每季度循环1次,对比2组师资查房考核成绩。结果对照组师资教学查房成绩为86.1175±5.51864,实验组师资教学查房成绩为87.9536±4.20446,差异具有统计学意义(P<0.05);趋势图显示对照组第1季度至第4季度师资查房成绩分别为87.6、84.95、85.51、86.29,成绩无明显差异,而实验组中第1季度至第4季度师资查房成绩分别为86.8、87.32、88.36、90.15,成绩呈现季度递增。2年度教学查房共性失分点季度改变对比趋势图中显示,PDCA循环后英语教授、检查护理问题、病例特点总结得分呈现季度递增。结论将PDCA循环运用于在师资教学查房督导中,可以有效解决查房中存在的实际问题,使整改更具有目的性,有效提高整改质量,有助于稳步提升师资教学查房水平,具有重要参考意义。     

Diplumbane-catalysed solvent- and additive-free hydroboration of ketones and aldehydes

A new diplumbane, namely [Pb(CH₂SiMe₃)₃]₂, was synthesized and structurally characterized. This group 14 element compound was found to catalyse the hydroboration of ketones and aldehydes under mild conditions without the use of additives and solvents, leading to the synthesis of a range of alcohols in high yields after hydrolysis.

A group 14 compound, diplumbane [Pb(CH₂SiMe₃)₃]₂, was synthesized and characterized, and it catalytic application for the efficient hydroboration of ketones and aldehydes was demonstrated for the first time.

The reduction of carbonyl compounds is an important transformation for the synthesis of alcohols, which are ubiquitous in organic chemistry.^1,2 The past decade has witnessed the development of numerous methods for this reaction including catalytic and non-catalytic ones, with particular interest in those involving pinacolborane (HBpin) as a reducing agent.^3,4 Catalytic hydroboration of ketones and aldehydes using HBpin provides a facile approach to various alcohols following easy hydrolysis of the corresponding boronate esters. In addition, this method has advantages such as superior chemoselectivity, low cost, and broad substrate scope over the traditional stoichiometric reduction.⁴ As a result, significant progress has been made with regards to the design and synthesis of effective catalysts for the hydroborative reduction of carbonyl compounds, which has been documented in several recent review articles.^5–8 While early transition metal complexes (containing, for example, Ti,⁹ V,¹⁰ Mn,¹¹ Fe,¹² Co,¹³ Ni,¹⁴ Cu,¹⁵ and Zn¹⁶) have been popular choices of catalysts, attention was expanded to main group element catalysts in recent years. In addition to the highly efficient metal hydridotriphenylborate hydroboration catalysts containing alkali (Li, Na, K) and alkali earth (Mg) metals that were first introduced by Okuda''s group,^17,18 other groups led by Hill,¹⁹ Mulvey,²⁰ and Sen²¹ have developed other useful catalysts with main group metals, including calcium. Moreover, the group 13 element aluminum has been used in organoaluminum hydrides or alkyl complexes for the hydroboration catalysis of ketones and aldehydes by the Roesky,²² Nembenna²³ and our groups,²⁴ respectively. Two examples of gallium-based catalysts were also reported by the Goicoechea²⁵ and Hevia²⁶ groups in 2021. Several catalysts utilizing group 14 elements (mainly Ge and Sn) were reported by the Jones,²⁷ Zhao,²⁸ and Nagendran²⁹ groups, as well as a silane catalyst stabilized by an amidinate ligand, namely PhC(N^tBu)₂SiHCl₂, reported by the Sen group.³⁰ These highlight the potential of main group elements for the development of active hydroboration catalysts.In contrast, the heavier group 14 element, lead, was almost unknown as a hydroboration catalyst. In 2017, Wesemann and co-workers reported a class of Lewis pair complexes, PhCH(PPh₂)M(Ar*) [M = Ge, Sn, or Pb; Ar* = 2,6-(2,4,6-ⁱPr₃C₆H₂)₂C₆H₃], which catalysed the hydroboration of a single aldehyde, hexanal (Scheme 1).³¹ However, no further demonstration of their catalytic activity towards other aldehydes and ketones was reported. Our recent interest in observing active hydroboration catalysts with a broad range of metals across the periodic table has led to the synthesis of an unprecedented diplumbane compound, namely [Pb(CH₂SiMe₃)₃]₂. Herein, we report the X-ray structure of this diplumbane and its application as an effective catalyst for the hydroboration of ketones and aldehydes under additive- and solvent-free conditions.Open in a separate windowScheme 1Lead-catalysed hydroboration of carbonyl compounds.Our recent work has focused on the utilization of 2,2′;6′,2′′-terpyridine (tpy) for the synthesis of novel Co, Mn, V and Al complexes for reduction catalysis.^{10,11a,13a,24} When the reaction of tpy with equimolar PbCl₂ was carried out in a THF solution, an insoluble white solid was obtained, which was isolated and characterized as (tpy)PbCl₂ (see ESI^†). (tpy)PbCl₂ is insoluble in common organic solvents, but well soluble in dimethyl sulfoxide (DMSO). Attempt to crystallizing this complex from a mixture of DMSO/toluene solution was unsuccessful; instead, an inorganic polymer [Pb₂Cl₄(DMSO)₃]_n was isolated without the incorporation of tpy ligand, indicating a M-tpy dissociation has occurred during crystallization, according to X-ray structural analysis (see ESI^†). Solid sample of (tpy)PbCl₂ was further used to react with LiCH₂SiMe₃ (2.2 equiv.) in diethyl ether for 4 h to give a pale-yellow solution after filtration. The concentrated reaction mixture was then cooled to −28 °C, and bright yellow block-like crystals of 1 were obtained in 46% yield (based on Si) after one week. Replacing the tpy ligand with 4′-Cl-tpy for the synthesis led to the isolation of 1 in a similar yield (48%). In addition, two independent attempts to prepare 1 by reacting PbCl₂ with LiCH₂SiMe₃ without the presence of tpy were unsuccessful, leading to unidentified oil. This indicates the significant role played by tpy ligands. It is believed that during the formation of 1, a process involving the oxidation of Pb from Pb^II to Pb^III occurred, along with the possible reduction of tpy ligand. This is consistent with the well-known redox-active nature of tpy.¹⁰ However, attempts to isolating the reduced product of tpy were unsuccessful, probably owing to its poor stability. 1 was characterized by IR, elemental analysis and solution NMR spectroscopy (see ESI^†). The solid-state structure was further revealed by X-ray crystallography. X-ray diffraction analysis confirmed that 1 crystallizes in the trigonal space group P3. The molecular structure of 1 is shown in Scheme 2. The structure features a dinuclear lead hexaalkyl compound, a diplumbane reminiscent of the known compound, [PbMe₂(CH₂SiMe₃)]₂, reported by Pannell in 1994, synthesized from (CH₂SiMe₃)Me₂PbBr and Mg or (Ph₃Sn)Li with yields of 7% and 18%, respectively.³² Our use of tpy as a ligand template using PbCl₂ as a starting material both simplifies the synthesis of this type of diplumbane and improves the yield, introducing a new synthetic methodology for this type of compounds. In 1, both Pb centers adopt a slightly distorted tetrahedral geometry with τ₄ parameters of 0.92 and 0.93, respectively, where a value of 1.00 represents a perfect tetrahedron.³³ The Pb–Pb bond distance is 2.89922(19) Å, slightly shorter than that in [PbMe₂(CH₂SiMe₃)]₂ (2.968(2) Å), yet comparable to those observed in several other R₃Pb–PbR₃ compounds (Pb–Pb bond lengths range from 2.839(2) Å to 2.908(2) Å).³⁴ The Pb–C bond lengths are also close to those reported.³⁴Open in a separate windowScheme 2The X-ray structure of diplumbane 1 with ORTEP diagram drawn at 30% thermal ellipsoids probability level. Selected bond lengths (Å): Pb1–Pb2 = 2.89922(19), Pb1–C11 = 2.260(8), Pb2–C21 = 2.243(8); and angles (°): C11–Pb1–Pb2 = 115.0(2), C11–Pb1–C11A = 103.5(3), C21–Pb2–Pb1 = 114.2(2), C21–Pb2–C21A = 104.4(3).1 was then examined as a catalyst for the hydroboration of ketones. Delightfully, it was found that the reaction of acetophenone with HBpin proceeded well in the presence of 0.25 mol% of 1, and quantitative conversion to the corresponding boronate ester was observed after 16 h under neat conditions at room temperature without the presence of additives. 1-Phenylethanol could be readily isolated in 94% yield after hydrolysis and purification via column chromatography with silica gel (2a, Scheme 3). A gram-scale synthesis of 2a was also carried out to confirm the practical usability of this catalyst. The efficacy of 1 is therefore well comparable to those well-performed transition metal catalysts reported for this reaction.^9–16 In addition, a control experiment using PbCl₂ instead of 1 led to only 5% gas chromatography (GC) yield of the corresponding boronate ester under the same conditions. Next, we applied this method to a broader range of ketones, featuring aromatic, aliphatic and cyclic substrates. The results are illustrated in Scheme 3. Acetophenones bearing halo groups were hydroborated successfully, affording the secondary alcohols 2b and 2c in 90% and 88% isolated yields, respectively. Both electron-donating and -withdrawing groups did not affect the catalytic activity (2d–f). In addition, functionalized ketones such as cyclopropyl phenyl ketone and α,β-unsaturated ketone were reduced selectively on the ketone site to give 2g and 2h with good yields. More challenging diaryl ketones worked as well for the hydroboration catalysed by 1 (2j and 2k). Finally, aliphatic and cyclic ketones were also used as substrates, and similar reactivity was observed (2l–o). However, either 3-acetylpyridine (for 2p) or 2-acetylpyridine was found to be almost inactive for this reaction, likely due to its coordination with 1 leading to deactivation of the reactive intermediate.Open in a separate windowScheme 3Lead-catalysed hydroboration of ketones.^{a a} Conditions: 1 (0.25 mol%), ketone (1.0 mmol) and HBpin (1.1 mmol), neat, 25 °C, 16 h, N₂. Yields of isolated alcohol products after column chromatography. ^b Reaction run at a 10 mmol scale. ^c GC yields of borate esters without hydrolysis using hexamethylbenzene as internal standard.1-Catalysed hydroboration was further extended to various aldehydes, and the results are summarized in Scheme 4. In general, benzaldehydes with halo, electron-donating or -withdrawing groups were hydroborated smoothly by 1 under neat conditions, affording primary alcohols (3a–g) in 84–96% yields. Cinnamaldehyde and aliphatic aldehydes were also active substrates for the hydroboration.Open in a separate windowScheme 4Lead-catalysed hydroboration of aldehydes.^{a a} Conditions: 1 (0.25 mol%), aldehyde (1.0 mmol) and HBpin (1.1 mmol), neat, 25 °C, 16 h, N₂. Yields of isolated alcohol products after column chromatography. ^b GC yields of borate esters without hydrolysis using hexamethylbenzene as internal standard.Next, chemoselective hydroboration was investigated with two reducible groups present. First, intermolecular competition experiments were carried out using benzaldehyde as a substrate in the presence of equimolar acetophenone or methyl benzoate. The results revealed that the aldehyde was selectively converted to the boronate ester, while the ketone and ester remained intact (Scheme 5). Then intramolecular competition reactions were conducted using methyl 4-formylbenzoate or diphenyl chalcone oxide with two reducible functionalities in each molecule. It was observed that the aldehyde or ketone was selectively reduced through hydroboration over the ester or epoxide, and boronate esters 4 and 5 were isolated without hydrolysis in 94% and 84% yields, respectively.Open in a separate windowScheme 5Chemoselective hydroboration catalysed by 1.Since metal hydrides often behave as the active catalyst for transition and main-group metal catalysed hydroboration,^6,35 we propose this as a possible mechanism for 1-catalysed hydroboration. Although attempts at isolating any reactive intermediate and/or a ketone substrate from the reactions of 1 with HBpin were unsuccessful, in situ NMR spectroscopy of the reaction of 1 with HBpin does show the formation of Me₃SiCH₂Bpin, which supports the formation of a possible hydride species I as shown in Scheme 6.³⁶ Thus, we hypothesize that an insertion/σ-bond metathesis type mechanism might have been under operation (Scheme 6). While we propose a mechanism involving a simple lead hydride (I, Scheme 6) generated from the reaction of precatalyst (1) with HBpin, other possible polyhydride species cannot be excluded. Next, C O insertion of carbonyl compound (ketone or aldehyde) into the Pb–H bond would lead to the formation of lead alkoxide IIIvia intermediate II after σ-bond metathesis. The lead alkoxide would then react with HBpin to afford the boronate ester through intermediate IV, releasing the lead hydride I and completing the catalytic cycle.Open in a separate windowScheme 6A plausible mechanism for the hydroboration of carbonyl compounds by 1 as a precatalyst. Only half of the Pb₂ species are shown for intermediates II–IV for clarity.     

Oriented self-assembly of metal–organic frameworks driven by photoinitiated monomer polymerization

The self-assembly of metal–organic frameworks (MOFs) is crucial for the functional design of materials, including energy storage materials, catalysts, selective separation materials and optical crystals. However, oriented self-assembly of MOFs is still a challenge. Herein, we propose a novel strategy to drive oriented self-assembly of MOF polyhedral particles at the water–liquid interface by photoinitiated monomer polymerization. The MOF polyhedral particles self-assemble into ordered close-packed structures with obvious orientation in the polymer film, and the orientation is determined by the casting solvent on the water surface. The prepared large-area MOF polymer films show a Janus structure, containing a MOF monolayer and a polymer layer, and can be easily transferred to a variety of substrates. In addition, mixed MOF particles with different sizes and morphologies can also be assembled by this method. This novel method can be foreseen to provide a powerful driving force for the development of MOF self-assembly and to create more possibilities for utilizing the anisotropic properties of MOFs.

The self-assembly of metal–organic frameworks (MOFs) is crucial for the functional design of materials, including energy storage materials, catalysts, selective separation materials and optical crystals.     

Dasatinib and interferon alpha synergistically induce pyroptosis-like cell death in philadelphia chromosome positive acute lymphoblastic leukemia

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) is a high-risk disease subtype with a dismal prognosis. Inhibiting BCR-ABL kinase alone is insufficient to eradicate Ph+ALL clones, and alternative BCR-ABL-dependent and -independent pathways need to be targeted as an effective strategy. Our study revealed that the combination of dasatinib and interferon-α showed synergistic activity against Ph+ALL, inducing mitochondrial dysfunction and causing necrosis-like cell lysis. Mechanistic studies showed that the induced cell death was caspase-3-independent. Canonical necroptosis signals, such as RIP1 and MLKL, were not activated; instead, the pyroptosis executor Gasdermin D was upregulated expression and activated. The expression levels of extracellular ATP and IL-1β were also upregulated, both of which are markers of pyroptotic cell death. In a murine Ph+ALL model, the dual drug treatment prolonged the survival of tumor-bearing mice. More importantly, we incorporated the dual drugs to maintenance therapy in 39 patients who were unfit for allogeneic stem cell transplantation (allo-HSCT). The median follow-up was 28.5 months, the 4-year disease-free survival and overall survival rates were 52.2% and 65.2%, respectively. Our data suggest that the combination of dasatinib and interferon-α has potential synergistic activity against Ph+ALL and shows promise as a maintenance therapy for Ph+ALL patients who are unfit for allo-HSCT.     

A case report on a child with fracture and dislocation of the upper cervical spine accompanied by spinal cord injury

Rationale:This study describes an 8-year-old boy with a C2 fracture and dislocation with a left C2–C3 articular process interlocking and spinal cord injury who underwent open reduction and internal fixation using the posterior cervical approach and achieved satisfactory results.Patient concerns:An 8-year-old boy underwent an emergency transfer from a previous hospital after a car accident.Diagnoses:Axial fracture and dislocation with spinal cord injury (American Spinal Injury Association grade C), traumatic shock, brain contusion, intracranial hemorrhage, mandibular fracture, pulmonary contusion and hemorrhage, left vertebral artery stenosis, and multiple fractures throughout the body. Radiological examination revealed a fracture of the lower edge of the C2 vertebral body, fourth-degree anterior spondylolisthesis of the C2 vertebral body, interlocking of the left C2–C3 articular processes, widening of the C2–C3 vertebral space, and occlusion of the V1 and 2 segments of the left vertebral artery.Interventions:The boy was immediately intubated and transferred to the pediatric intensive care unit for rescue treatment. However, the reduction was unsuccessful with 2 weeks of cranial traction. Thus, an open reduction was performed under general anesthesia. One month after the surgery, the boy was discharged from the hospital on foot after rehabilitation treatment.Outcomes:The boy was discharged from the hospital 1 month after surgery. At the 8-month follow-up, a radiological examination showed that the corrected C2 vertebral body fracture and dislocation were satisfactorily reduced, and the spinal cord was adequately decompressed. The internal fixation position was also good, and the spinal sequence had recovered well. In summary, except for the muscle strength of the right upper limb, which was slightly worse, the other clinical symptoms were significantly improved.Lessons:In treating cervical fracture and dislocation with unilateral facet lock, the posterior open reduction of pedicle screw and lateral mass screw internal fixation achieved satisfactory results. Consequently, treating complex cervical spine injuries in children requires an accurate diagnosis and careful treatment strategy.     

不同浸泡时间对浙贝母有效成分提取的影响

目的以贝母素甲、贝母素乙作为指标成分,研究不同浸泡时间对浙贝母有效成分提取的影响,考察比较合理的煎煮方法。方法采用高效液相色谱一蒸发光散射器（HPLC—ELSD）法检测,DionexAcclaimC18色谱柱（250mm×4．6mm,5μm）,流动相为乙腈-0．1％二乙胺（70：30）,流速为1．0mL／min;ELSD条件为漂移管温度42℃,载气（高纯N2）流速1．0L／min。结果不同浸泡时间对浙贝母饮片有效成分提取量差异明显。随着饮片浸泡时间的延长,煎煮后药渣的白心率降低,而煎膏得率及其有效成分提取量均增高。结论浙贝母饮片用常规煎煮方法很难煮透,至少应先浸泡1h,才能使有效成分较好地溶出,发挥更好的药效。