Laboratory-developed Droplet Digital PCR Assay for Quantification of the JAK2 V617F Mutation.

Precise quantification of the JAK2 V617F mutation using highly sensitive assays is crucial for diagnosis, treatment process monitoring, and prognostic prediction in myeloproliferative neoplasms' (MPNs) patients. Digital droplet polymerase chain reaction (ddPCR) enables precise quantification of low-level mutations amidst a high percentage of wild type alleles without the need for external calibrators or endogenous controls. The objective of this study was to optimize a ddPCR assay for detecting the JAK2 V617F mutation and establish it as a laboratory-developed ddPCR assay in our center. The optimization process involved fine-tuning five key parameters: primer/probe sequences and concentrations, annealing temperature, template amount, and PCR cycles. Our ddPCR assay demonstrated exceptional sensitivity, and the limit of quantification (LoQ) was 0.01% variant allele frequency with a coefficient of variation of approximately 76%. A comparative analysis with quantitative PCR on 39 samples showed excellent consistency (r = 0.988). In summary, through rigorous optimization process and comprehensive analytic performance validation, we have established a highly sensitive and discriminative laboratory-developed ddPCR platform for JAK2 V617F detection. This optimized assay holds promise for early detection of minimal residual disease, personalized risk stratification, and potentially more effective treatment strategies in MPN patients and non-MPN populations.

Smart windows based on ultraviolet-B persistent luminescence phosphors for bacterial inhibition and food preservation.

Herein, ultraviolet B (UVB) persistent luminescence phosphors containing SrAl12O19: Ce3+, Sc3+ nanoparticles were reported. Thermoluminescence (TL) spectrum analysis reveals that the shallow trap induced by Sc3+ co-doping plays an important role in photoluminescence persistent luminescence (PersL) development, while the deep trap dominates the generation of optical stimulated luminescence (OSL). Owing the appearance of deep trap, the OSL is observed under light (700 nm - 900 nm) excitation. UVB luminescence exerts good bactericidal effects on pathogenic bacteria involved in the process of food spoilage. Thus, the smart window with SrAl12O19: Ce3+, Sc3+/PDMS produces UVB PersL to efficiently inactivate Escherichia coli and Staphylococcus aureus. In addition, the presence of the smart window delays the critical point of pork decay, and greatly reduces the time of pork spoilage. It maximizes the convenience of eradicating bacteria and preserving food, thus offering a fresh perspective on the use of UV light for food sterilization and preservation.

EVLncRNAs 3.0: an updated comprehensive database for manually curated functional long non-coding RNAs validated by low-throughput experiments.

Long noncoding RNAs (lncRNAs) have emerged as crucial regulators across diverse biological processes and diseases. While high-throughput sequencing has enabled lncRNA discovery, functional characterization remains limited. The EVLncRNAs database is the first and exclusive repository for all experimentally validated functional lncRNAs from various species. After previous releases in 2018 and 2021, this update marks a major expansion through exhaustive manual curation of nearly 25 000 publications from 15 May 2020, to 15 May 2023. It incorporates substantial growth across all categories: a 154% increase in functional lncRNAs, 160% in associated diseases, 186% in lncRNA-disease associations, 235% in interactions, 138% in structures, 234% in circular RNAs, 235% in resistant lncRNAs and 4724% in exosomal lncRNAs. More importantly, it incorporated additional information include functional classifications, detailed interaction pathways, homologous lncRNAs, lncRNA locations, COVID-19, phase-separation and organoid-related lncRNAs. The web interface was substantially improved for browsing, visualization, and searching. ChatGPT was tested for information extraction and functional overview with its limitation noted. EVLncRNAs 3.0 represents the most extensive curated resource of experimentally validated functional lncRNAs and will serve as an indispensable platform for unravelling emerging lncRNA functions. The updated database is freely available at https://www.sdklab-biophysics-dzu.net/EVLncRNAs3/.

Influence of starch silylation on the structures and properties of starch/epoxidized soybean oil-based bioplastics.

The present work systematically investigated the influence of starch silylation on the structures and properties of starch/epoxidized soybean oil-based bioplastics. Silylated starch was synthesized using starch particles (SP-ST) or gelatinized starch (SG-ST) under different silane hydrolysis pHs. Due to the appearance of -NH2 groups and lower OH wavenumbers, SP-ST obtained at pH 5 showed higher silylation degree and stronger hydrogen bond interaction with epoxidized soybean oils (ESO) than that at pH 11. The morphology analysis revealed better interfacial compatibility of ESO and SP-ST. The tensile strength of the samples containing SP-ST increased by 51.91 % than the control, emphasizing the enhanced interaction within the bioplastics. However, tensile strength of the bioplastics with SG-ST decreased by 59.56 % due to their high moisture contents from unreacted silanes. Additionally, the bioplastics with SG-ST exhibited an obvious reduction of thermal stability and an increase in water solubility because of the presence of unreacted APMS. The bioplastic degradation was not prevented by starch silylation except high pH. The bioplastics showed the most desirable tensile properties, thermal stability, and water solubility when starch was surface-modified with silanes hydrolyzed at pH 5. These outcomes made the fabricated bioplastics strong candidates for petroleum-based plastics for packaging applications.

Multifunctionality of Jasmonic Acid Accumulation during Aphid Infestation in Altering the Plant Physiological Traits That Suppress the Plant Defenses in Wheat Cultivar XN979.

Crop plants have coevolved phytohormone-mediated defenses to combat and/or repel their colonizers. The present study determined the effects of jasmonic acid (JA) accumulation during aphid infestation on the preference and performance of Sitobion miscanthi Takahashi (Hemiptera: Aphididae), and its potential role in fine-tuning hormone-dependent responses in XN979 wheat cultivar seedlings was evaluated via the transcriptional profiles of marker genes related to JA- and salicylic acid (SA)-dependent responses. The preference experiment and the life table data reveal that direct foliage spraying of 2.5 mM methyl jasmonate (MeJA) exhibited weak negative or positive effects on the preferential selection and the population dynamics and oviposition parameters of S. miscanthi. The transcription level of phytohormone biosynthesis genes shows that foliage spraying of MeJA significantly upregulated the marker genes in the JA biosynthesis pathway while downregulating the SA pathway. In addition, either MeJA treatment or previous aphid infestation significantly induced upregulated transcription of the genes involved in the JA- and SA-dependent defense responses, and the transcription level of the tryptophan decarboxylase (TaTDC) gene, which facilitates the conversion of L-tryptophan to tryptamine, was rapidly upregulated after the treatments as well. The main products of tryptamine conversion could play a crucial role in suppressing SA-dependent defense responses. These results will provide more experimental evidence to enable understanding of the antagonistic interaction between hormone signaling processes in cereals under aphid infestation.

Homologous genes shared between probiotics and pathogens affect the adhesion of probiotics and exclusion of pathogens in the gut mucus of shrimp.

Clarifying mechanisms underlying the selective adhesion of probiotics and competitive exclusion of pathogens in the intestine is a central theme for shrimp health. Under experimental manipulation of probiotic strain (i.e., Lactiplantibacillus plantarum HC-2) adhesion to the shrimp mucus, this study tested the core hypothesis that homologous genes shared between probiotic and pathogen would affect the adhesion of probiotics and exclusion of pathogens by regulating the membrane proteins of probiotics. Results indicated that the reduction of FtsH protease activity, which significantly correlated with the increase of membrane proteins, could increase the adhesion ability of L. plantarum HC-2 to the mucus. These membrane proteins mainly involved in transport (glycine betaine/carnitine/choline ABC transporter choS, ABC transporter, ATP synthase subunit a atpB, amino acid permease) and regulation of cellular processes (histidine kinase). The genes encoding the membrane proteins were significantly (p < 0.05) up-regulated except those encoding ABC transporters and histidine kinases in L. plantarum HC-2 when co-cultured with Vibrio parahaemolyticus E1, indicating that these genes could help L. plantarum HC-2 to competitively exclude pathogens. Moreover, an arsenal of genes predicted to be involved in carbohydrate metabolism and bacteria-host interactions were identified in L. plantarum HC-2, indicating a clear strain adaption to host's gastrointestinal tract. This study advances our mechanistic understanding of the selective adhesion of probiotics and competitive exclusion of pathogens in the intestine, and has important implications for screening and applying new probiotics for maintaining gut stability and host health.

Overcoming Debye length limitations: Three-dimensional wrinkled graphene field-effect transistor for ultra-sensitive adenosine triphosphate detection.

Adenosine triphosphate (ATP) is closely related to the pathogenesis of certain diseases, so the detection of trace ATP is of great significance to disease diagnosis and drug development. Graphene field-effect transistors (GFETs) have been proven to be a promising platform for the rapid and accurate detection of small molecules, while the Debye shielding limits the sensitive detection in real samples. Here, a three-dimensional wrinkled graphene field-effect transistor (3D WG-FET) biosensor for ultra-sensitive detection of ATP is demonstrated. The lowest detection limit of 3D WG-FET for analyzing ATP is down to 3.01 aM, which is much lower than the reported results. In addition, the 3D WG-FET biosensor shows a good linear electrical response to ATP concentrations in a broad range of detection from 10 aM to 10 pM. Meanwhile, we achieved ultra-sensitive (LOD: 10 aM) and quantitative (range from 10 aM to 100 fM) measurements of ATP in human serum. The 3D WG-FET also exhibits high specificity. This work may provide a novel approach to improve the sensitivity for the detection of ATP in complex biological matrix, showing a broad application value for early clinical diagnosis and food health monitoring. Electronic supplementary materials: The online version contains supplementary material available at 10.1007/s11467-023-1281-7 and https://journal.hep.com.cn/fop/EN/10.1007/s11467-023-1281-7.

Comparison of three methods for measuring C0-1 angles and C0-2 angles.

BACKGROUND: The mutual compensatory relationship between the upper cervical sagittal alignment and the lower cervical sagittal alignment has been repeatedly reported. However, the evaluation of the upper cervical sagittal parameters are varied in previous studies. This retrospective study was performed to compare three methods for measuring the upper cervical sagittal parameters. METHODS: A total of 263 individuals with standing neutral lateral cervical radiographs were included in this study. The Frankfort horizontal line (FHL), foramen magnum line (FML), and McGregor line (ML) were separately used as the reference lines for measuring the C0-1 angle and C0-2 angle. Intraclass correlation (ICC) values were used to compare the consistency and repeatability of the three methods. Pearson's correlation analysis was used to analyze the correlation between the sagittal parameters of the upper and lower cervical spine. RESULTS: The interobserver and intraobserver ICC values obtained from using the ML to measure the C0-1 angle and C0-2 angle were both higher than those obtained from using the FML or FHL. The C0-1 angle and C0-2 angle measured by the three methods were negatively correlated with the C2-7 angle. The upper sagittal parameters measured by the FHL were the most correlated with the C2-7 angle. The correlation between the C0-1 angle measured by the three methods and the C0-2 angle measured with the FHL or ML and the C2-7 angle increased with aging. CONCLUSION: Use of the ML to measure the C0-1 angle and C0-2 angle has higher reliability. Use of the FHL to measure the sagittal alignment of the upper cervical spine is more suitable for evaluating the compensation mechanism between the upper and the lower cervical spine.

Nanowire-in-bowl-shaped piezoelectric cavity structure for SERS directional detection of nanoplastics less than 50†nm.

The accurate detection of nanoplastics is crucial due to their harmful effects on the environment and human beings. However, there is a lack of detection methods for nanoplastics smaller than 50 nm. In this research, we successfully constructed an Ag/CuO nanowire (NW)/BaTiO3@Polyvinylidene fluoride (PVDF) Bowl-shaped substrate with a nanowire-in-Bowl-shaped piezoelectric cavity structure that can modulate surface-enhanced Raman scattering (SERS) by the piezoelectric effect by the virtue of the tip effect of the CuO NW and light focusing effect of the Bowl-shaped cavity. Due to its unique nanowire-in-Bowl-shaped structure and piezoelectrically modifiable ability, nanoplastics less than 50 nm were successfully detected and quantitatively analyzed. We believe that the Ag/CuO NW/BaTiO3@PVDF Bowl-shaped substrate can provide an efficient, accurate, and feasible way to achieve qualitative and quantitative detection of nanoplastics.

Preparation and characterization of bioplastics from silylated cassava starch and epoxidized soybean oils.

In this work, a systematic coupling study of silane coupling agent between starch and epoxidized soybean oils (ESO) was carried out. Starch was modified by 3-aminopropyl trimethoxy silane (APMS) with various contents of NaOH. The APMS-modified starch was incorporated with ESO to synthesize the bioplastics by solution casting. As demonstrated by the FTIR spectra, the hydrogen bond interactions among starch molecules were inhibited by the modification. This outcome provided higher interaction and compatibility of starch with ESO, as confirmed by FESEM. TGA showed that the thermal stability of starch decreased considerably after the silylation. In contrast, the produced bioplastics with silylated starch exhibited higher thermal stability than the control sample. Regarding the bioplastics, an obvious increase of tensile strength from 5.78 MPa to 9.29 MPa was obtained. This work suggested a simple and effective modification technique by APMS to improve compatibility of starch/ESO-based bioplastics with superior mechanical and thermal properties.

Mechanical stretching boosts expansion and regeneration of intestinal organoids through fueling stem cell self-renewal.

Intestinal organoids, derived from intestinal stem cell self-organization, recapitulate the tissue structures and behaviors of the intestinal epithelium, which hold great potential for the study of developmental biology, disease modeling, and regenerative medicine. The intestinal epithelium is exposed to dynamic mechanical forces which exert profound effects on gut development. However, the conventional intestinal organoid culture system neglects the key role of mechanical microenvironments but relies solely on biological factors. Here, we show that adding cyclic stretch to intestinal organoid cultures remarkably up-regulates the signature gene expression and proliferation of intestinal stem cells. Furthermore, mechanical stretching stimulates the expansion of SOX9+ progenitors by activating the Wnt/ß-Catenin signaling. These data demonstrate that the incorporation of mechanical stretch boosts the stemness of intestinal stem cells, thus benefiting organoid growth. Our findings have provided a way to optimize an organoid generation system through understanding cross-talk between biological and mechanical factors, paving the way for the application of mechanical forces in organoid-based models.

Plasmonic enhanced piezoelectric photoresponse with flexible PVDF@Ag-ZnO/Au composite nanofiber membranes.

The coordination of piezoelectric and plasmonic effects to regulate the separation and migration of photo-generated carriers is still a significant method to improve the performance of visible-light photoresponse. Herein, we propose the PVDF@Ag-ZnO/Au composite nanofiber membranes utilizing the piezoelectric and plasmonic effects to promote the photocatalytic degradation of organic dyes. Here, ZnO nanorods can generate a built-in electric field under vibration to separate electron-hole pairs. The Schottky junction formed by noble metal/semiconductor can not only inhibit the recombination of photo-generated carriers and accelerate the migration of carriers, but also enhance the utilization of visible light. In addition, the structure has excellent flexibility and easy recycling characteristics. We demonstrate that the plasmonic effect of noble metal can enhance the light response of membranes and broaden light absorption from ultraviolet to visible light region. With the help of the surface-enhanced Raman scattering (SERS), modulation effects of the piezoelectric effect on light response is proved. For catalytic processes, rhodamine B (98.8%) can be almost completely degraded using PVDF@Ag-ZnO/Au within 120 minutes in the piezoelectric photocatalysis process, which is 2.2 and 2.8 times higher than photocatalysis and piezoelectric catalysis, respectively. This work provides a promising strategy for harnessing solar and mechanical energy.

Distribution and health risks of organic micropollutants from home dusts in Malaysia.

Indoor dust is an important medium to evaluate human exposure to emerging organic contaminants. The principal aim of this study was to determine overall status of organic micropollutants (OMPs) of indoor dust in Kuala Lumpur, Malaysia and assess their corresponding health risks. One hundred thirty-three OMPs, ascribed to 13 chemical groups, were screened by Automated Identification and Quantification System with a GC-MS database. The concentrations of OMPs ranged between 460 and 4000 µg/g, with the median concentration of 719 µg/g. The dominant chemical groups were ascribed to n-alkanes (median: 274 µg/g), plasticizers (151 µg/g), sterols (120 µg/g), and pesticides (42.6 µg/g). Cholestrol was the most abundant compound (median: 115 µg/g). Different sources and usage patterns of OMPs in various houses were expected. Toxicity values of OMPs were obtained from existing databases or predicted by quantitative structure-activity relationship models. Cumulative hazard quotients for OMPs through ingestion route were lower than one for all the dust samples, demonstrating that there was no remarkable non-cancer risk. The cancer risks of these OMPs were greater than 10-4, with cholestrol dominating 99.1% of the carcinogenic risks, which suggested that there was a significant cancer risk. This study might offer a benchmark to ensure the safety of chemical usages in future in Malaysia.

The Origin of Mo2C Films for Surface-Enhanced Raman Scattering Analysis: Electromagnetic or Chemical Enhancement?

The relatively weak Raman enhanced factors of semiconductor-based substrate limit its further application in surface-enhanced Raman scattering (SERS). Here, a kind of two-dimensional (2D) semimetal material, molybdenum carbide (Mo2C) film, is prepared via a chemical vapor deposition (CVD) method, and the origin of SERS is investigated for the first time. The detection limits of the prepared Mo2C films for crystal violet (CV) and rhodamine 6G (R6G) molecules are low at 10-6 M and 10-8 M, respectively. Our detailed theoretical analysis, based on density functional theory and the finite element method, demonstrates that the enhancement of the 2D Mo2C film is indeed CM in nature rather than the EM effects. Besides, the basic doping strategies are proposed to further optimize the SERS sensitivity of Mo2C for Fermi level regulation. We believe this work will provide a helpful guide for developing a highly sensitive semimetal SERS substrate.

Near-Infrared-Responded High Sensitivity Nanoprobe for Steady and Visualized Detection of Albumin in Hepatic Organoids and Mouse Liver.

Exploring the advanced techniques for protein detection facilitates cell fate investigation. However, it remains challenging to quantify and visualize the protein with one single probe. Here, a luminescent approach to detect hepatic cell fate marker albumin in vitro and living cell labeling with upconversion nanoparticles (UCNPs), which are conjugated with antibody (Ab) and rose bengal hexanoic acid (RBHA) is reported. To guarantee the detection quality and accuracy, an "OFF-ON" strategy is adopted: in the presence of albumin, the luminescence of nanoparticles remains suppressed owing to energy transfer to the quencher. Upon albumin binding to the antibody, the luminescence is recovered under near-infrared light. In various bio-samples, the UCNPs-Ab-RBHA (UCAR) nanoprobe can sense albumin with a broad detection range (5-315 ng mL-1 ). When applied to liver ductal organoid culture medium, the UCAR can monitor hepatocyte differentiation in real time by sensing the secreted albumin. Further, UCAR enables live imaging of cellular albumin in cells, organoids, and tissues. In a CCl4 -induced liver injury model, UCAR detects reduced albumin in liver tissue and serum. Thus, a biocompatible nanoprobe for both quantification and imaging of protein in complex biological environment with superior stability and high sensitivity is provided.

Qualitative and quantitative detection of microcystin-LR based on SERS-FET dual-mode biosensor.

Microcystin-LR (MC-LR), a kind of hepatoxin produced by cyanobacteria blooms, can promote liver cancer through long-term exposure even at low concentrations. In this study, a novel biosensor based on surface-enhanced Raman scattering (SERS) and field effect transistor (FET) dual sensing mode was developed by using gold nanoparticles (AuNPs)/graphene composite as sensing material. Based on the SERS sensing mode, the Raman fingerprint spectrum of MC-LR was obtained through the specific combination of MC-LR aptamer and MC-LR. The SERS enhanced effect of the AuNPs was also verified by theoretical simulation. By using FET sensing mode, the graphene field effect transistor (G-FET) biosensor respectively exhibited the detection limit as low as 0.62 aM and 0.91 aM in phosphate buffered saline (PBS) and human serum, and showed a good linear relationship in a wide range of 1 × 10-18 to 1 × 10-8 M in both solutions. Meanwhile, the sensor was utilized for the detection of MC-LR in actual water samples, and the complex components in the water did not interfere with MC-LR detection, indicating a significant high specificity of the sensor. The SERS-FET dual-mode biosensor can provide more detection options and improve the reliability of measurement results, which may has a great application prospect in the field of water environment detection.

Construction of a dual-model aptasensor based on G-quadruplexes generated via rolling circle amplification for visual/sensitive detection of kanamycin.

A dual-model colorimetric and electrochemical aptasensor was designed using a large number of G-quadruplexes generated by rolling circle amplification (RCA). Specific binding between target and aptamer during RCA yielded large numbers of G-quadruplexes. A colorimetric sensor was fabricated based on the interaction between the G-quadruplex and hemin, which altered the 3,3',5,5'-Tetramethylbenzidine (TMB)-catalyzed color reaction and facilitated the visual and semi-quantitative detection of kanamycin. An electrochemical sensor was constructed based on the strong interaction between the G-quadruplex and the methylene blue electrical signal molecule. Combining nanocomposites multi-walled carbon nanotubes-chitosan/gold nanoparticles (MWCNTs-CS/AuNPs) and RCA realized double-amplified electrochemical signals. Under optimized conditions, a linear relationship was obtained as the logarithm of different concentrations of kanamycin (KAN). The colorimetric aptasensor had a linear range of 1 × 102 nM to 1 × 103 nM with a detection limit of 1.949 nM. The electrochemical aptasensor had wider a linear range from 1 × 10-3 nM to 2.5 × 103 nM and a lower detection limit of 0.333 pM. The sensor combined the advantages of simple colorimetric visualization with the ultra-precision of electrochemical methods. Aptasensor showed good specificity and prevented interference. Furthermore, the prepared dual-model aptasensor facilitated the practical monitoring of KAN in milk.

LSPR optical fiber sensor based on 3D gold nanoparticles with monolayer graphene as a spacer.

Localized surface plasmon resonance (LSPR) optical fiber biosensing is an advanced and powerful label-free technique which gets great attention for its high sensitivity to refractive index change in surroundings. However, the pursuit of a higher sensitivity is still challenging and should be further investigated. In this paper, based on a monolayer graphene/gold nanoparticles (Grm/Au NPs) three-dimensional (3D) hybrid structure, we fabricated a D-shaped plastic optical fiber (D-POF) LSPR sensor using a facile two-step method. The coupling enhancement of the resonance of this multilayer structure was extremely excited by the surface plasmon property of the stacked Au NPs/Grm layer. We found that the number of plasmonic structure layers was of high importance to the performance of the sensor. Moreover, the optimal electromagnetic field enhancement effect was found in three-layer plasmonic structure. Besides, the n*(Grm/Au NPs)/D-POF sensor exhibited outstanding performance in sensitivity (2160 nm/RIU), linearity (linear fitting coefficient R2 = 0.996) and reproducibility. Moreover, the sensor successfully detected the concentration of glucose, achieving a sensitivity of 1317.61 nm/RIU, which suggested a promising prospect for the application in medicine and biotechnology.

Identification of prognostic signature with seven LncRNAs for papillary thyroid carcinoma.

PURPOSE: With the increasing incidence of thyroid cancer (TC), the prognostic risk assessment of thyroid cancer has been becoming more and more important. The aim of this study was to screen TC-related biomarkers and identify key multi-long non coding RNA (lncRNA) signature for prognostic risk assessment of papillary TC. MATERIAL AND METHODS: The lncRNAs differentially expressed between TC tissue and adjacent normal tissue was identified by R language. Bioinformatics analysis was applied to screen the lncRNAs significantly associated with prognosis in TC patients and build the multi-lncRNA signature. The lncRNAs were annotated by co-expression and enrichment analysis to demonstrate the underlying mechanism of their effect on prognosis. RESULTS: 285 up-regulated and 174 down-regulated differently expressed lncRNAs were identified. Based on seven signature lncRNAs (AL591846.2, AC253536.3, AC004112.1, LINC00900, AC008555.1, TNRC6C-AS1, LINC01736) a prognostic risk assessment model was built. The model can segregate the patients into the high-risk and low-risk groups (P value <0.0001, CI: 0.02∼0.14). ROC analysis revealed that the area under the curve reached 0.86, indicating that this model had an excellent sensitivity and specificity. Also, the model could act as an independent prognostic indication (HR â€‹= â€‹2.90, P value â€‹= â€‹0.0094 with multivariate analysis). Annotation results further supported and enriched our understanding of the seven signature lncRNAs. Importantly, expression levels of three of the seven lncRNAs were confirmed in Gene Expression Omnibus (GEO) data. CONCLUSIONS: This study has provided a promising method for the prognostic risk assessment in patients with TC.

Management of fresh odontoid fractures using posterior C1-2 fixation without fusion: a long-term clinical follow-up study.

OBJECTIVE: Posterior C1-2 fixation without fusion makes it possible to restore atlantoaxial motion after removing the implant, and it has been used as an alternative technique for odontoid fractures; however, the long-term efficacy of this technique remains uncertain. The purpose of the present study was to explore the long-term follow-up outcomes of patients with odontoid fractures who underwent posterior C1-2 fixation without fusion. METHODS: A retrospective study was performed on 62 patients with type II/III fresh odontoid fractures who underwent posterior C1-2 fixation without fusion and were followed up for more than 5 years. The patients were divided into group A (23 patients with implant removal) and group B (39 patients without implant removal) based on whether they underwent a second surgery to remove the implant. The clinical outcomes were recorded and compared between the two groups. In group A, the range of motion (ROM) of C1-2 was calculated, and correlation analysis was performed to explore the factors that influence the ROM of C1-2. RESULTS: A solid fracture fusion was found in all patients. At the final follow-up, no significant difference was found in visual analog scale score or American Spinal Injury Association Impairment Scale score between the two groups (p > 0.05), but patients in group A had a lower Neck Disability Index score and milder neck stiffness than did patients in group B (p < 0.05). In group A, 87.0% (20/23) of the patients had atlantoodontoid joint osteoarthritis at the final follow-up. In group A, the C1-2 ROM in rotation was 6.1° ± 4.5° at the final follow-up, whereas the C1-2 ROM in flexion-extension was 1.8° ± 1.2°. A negative correlation was found between the C1-2 ROM in rotation and the severity of tissue injury in the atlantoaxial region (r = -0.403, p = 0.024) and the degeneration of the atlantoodontoid joint (r = -0.586, p = 0.001). CONCLUSIONS: Posterior C1-2 fixation without fusion can be used effectively for the management of fresh odontoid fractures. The removal of the implant can further improve the clinical efficacy, but satisfactory atlantoaxial motion cannot be maintained for a long time after implant removal. A surgeon should reconsider the contribution of posterior C1-2 fixation without fusion and secondary implant removal in preserving atlantoaxial mobility for patients with fresh odontoid fractures.