Novel MRI signs of the atlantodental space in patients with atlantoaxial dislocation.

OBJECTIVES: The type of atlantodental space tissue in patients with atlantoaxial dislocation (AAD) can help doctors understand the possibility of reduction before surgery. However, relevant research on this topic is lacking. In this study, we aimed to summarise the atlantodental space classification of patients with AAD using magnetic resonance imaging (MRI) and explore their clinical characteristics. MATERIALS AND METHODS: Preoperative 3T cervical MR images of patients who underwent posterior reduction and fixation surgery for non-traumatic AAD between 1 September 2012 and 31 July 2023 were collected. Two radiologists read and recorded the MRI results based on the standard protocol. The kappa value was used to evaluate intra- and inter-observer agreements. The patient's age, sex, body mass index, clinical symptoms, Japanese Orthopaedic Association (JOA) score, and visual analogue scale information were obtained from medical records. RESULTS: A total of 135 patients with AAD (mean age, 51.3 ± 14.0 years, 52 men) were included in the analysis. The inter-observer agreement between the two readers was 0.818 (P < 0.0001). The intra-observer consistencies were 0.882 (P < 0.0001) and 0.896 (P < 0.0001). Patients with inflexible tissue signs exhibit more irreducible in hyperextension position, and their range of motion of ADI is smaller. These patients were older and had a higher incidence of abnormal spinal cord signals and JOA scores. CONCLUSIONS: Novel MRI signs exhibited high inter- and intra-observer consistency and were associated with patient age, abnormal spinal cord signals, reducibility, range of motion of ADI, and symptoms.

Sagittal slope angle of lateral atlantoaxial articulation is associated with the severity of basilar invagination with atlantoaxial dislocation and predicts reduction degree after surgery.

OBJECTIVE: To investigate (1) lateral atlantoaxial articulation (LAA) morphology in patients with basilar invagination (BI) with atlantoaxial dislocation (AAD) and healthy individuals and its relationship with the severity of dislocation and (2) the effect of the LAA morphology on reduction degree (RD) after surgery. METHODS: In this retrospective propensity score matching case-control study, imaging and baseline data of 62 patients with BI and AAD from 2011 to 2022 were collected. Six hundred thirteen  participants without occipitocervical junctional deformity served as controls. Logistic regression and receiver operating characteristic (ROC) curve were used for analysis. RESULTS: The age, BMI and sex did not differ significantly between the two groups after propensity score matching. Sagittal slope angle (SSA) and coronal slope angle (CSA) was lower and greater, respectively, in the patient group than in the control group. A negative SSA value usually indicates anteverted LAA. Regression analysis revealed a significant negative correlation between SSA and severity of dislocation. However, no relationship was found between CSA and the severity of dislocation. The multivariate logistic regression analysis revealed that minimum-SSA emerged as an independent predictor of satisfactory reduction (RD ≥ 90%). The ROC curve demonstrated an area under the curve of 0.844, with a cut-off value set at -40.2. CONCLUSION: SSA in patients group was significantly smaller and more asymmetric than that in the control group. Dislocation severity was related to SSA but not to CSA. Minimum-SSA can be used as a predictor of horizontal RD after surgery.

Does Screw Number of Zero-profile Implants in Fusion Segment Influence Intervertebral Stability?

OBJECTIVE: The unclear clinical outcomes of two different zero-profile implants with different number of screws in hybrid surgery restricts the choice of patient-specific implants. This study aims to compare two different implants on its postoperative subsidence, motion stabilization and clinical outcomes. It also provides references to the most reasonable implant choice in fusion surgery. METHODS: This was a retrospective study. From February 2014 to March 2022, 173 patients who underwent hybrid surgery were included. Among them, 122 received surgery with a four screw implant, while 51 received a two screw implant. We analyzed the significance of patient-specific factors, radiographic factors and clinical outcomes. The Wilcoxon rank sum test, t tests/analysis of variance (ANOVA) test and stepwise multivariate logistic regression were adopted for statistical analysis. RESULTS: No statistically significant difference was observed between the two screw and four screw groups in terms of immediate, middle, and long-term stability and fusion rate (p > 0.05). However, the two screws group had higher FSU height subsidence at 3, 6, and 12 months postoperatively and higher rates of significant subsidence at three and 6 months postoperatively (p < 0.05). Both groups showed significant clinical improvements at the final follow-up. CONCLUSION: Two screw and four screw implants provide comparable stability, fusion rates and clinical outcomes. However, the two screw implant was inferior to the four screw implant in subsidence prevention. Therefore, the two-screw implant is non-inferior to the four-screw implant in most patients. It can be used as the priority choice in the fusion segment by its easy manageability. However, the patients with a high risk of subsidence such as multilevel surgery, the elderly, lower BMD, bad cervical alignment should receive a four screw implant rather than a two screw implant.

Risk Factors of Nonfusion after Anterior Cervical Decompression and Fusion in the Early Postoperative Period: A Retrospective Study.

OBJECTIVE: Although high fusion rates have been reported for anterior cervical decompression and fusion (ACDF) in the medium and long term, the risk of nonfusion in the early period after ACDF remains substantial. This study investigates early risk factors for cage nonfusion in patients undergoing single- or multi-level ACDF. METHODS: This was a retrospective study. From August 2020 to December 2021, 107 patients with ACDF, including 197 segments, were enrolled, with a follow-up of 3 months. Among the 197 segments, 155 were diagnosed with nonfusion (Nonfusion group), and 42 were diagnosed with fusion (Fusion group) in the early period after ACDF. We assessed the significance of the patient-specific factors, radiographic indicators, serum factors, and clinical outcomes. The Wilcoxon rank sum test, t-tests, analysis of variance, and stepwise multivariate logistic regression were used for statistical analysis. RESULTS: Univariate analysis showed that smoking, insufficient improvement in the C2-7 Cobb angle (p = 0.024) and the functional spinal unit Cobb angle (p = 0.022) between preoperative and postoperative stages and lower serum calcium (fusion: 2.34 ± 0.12 mmol/L; nonfusion: 2.28 ± 0.17 mmol/L, p = 0.003) ß-carboxyterminal telopeptide end of type 1 collagen (ß-CTX) (fusion: 0.51 [0.38, 0.71]; nonfusion: 0.43 [0.31, 0.57], p = 0.008), and N-terminal fragment of osteocalcin (N-MID-BGP) (fusion: 18.30 [12.15, 22.60]; nonfusion: 14.45 [11.65, 18.60], p = 0.023) are risk factors for nonfusion in the early period after ACDF. Stepwise logistic regression analysis revealed that poor C2-7 Cobb angle improvement (odds ratio [OR], 1.107 [1.019-1.204], p = 0.017) and lower serum calcium (OR, 3.700 [1.138-12.032], p = 0.030) are risk factors. CONCLUSIONS: Patients with successful fusion after ACDF had higher preoperative serum calcium and improved C2-7 Cobb angle than nonfusion patients at 3 months. These findings suggest that serum calcium could be used to identify patients at risk of nonfusion following ACDF and that correcting the C2-7 Cobb angle during surgery could potentially increase fusion in the early period after ACDF.

Zero-Profile Implant System for Treatment of Dysphagia Caused by Noncontiguous Anterior Cervical Osteophytes-A Case Report with Literature Review.

BACKGROUND: Esophageal cervical spondylosis is a rare type of cervical spondylosis which causes dysphagia. Surgical osteophyte resection is taken when conservative treatment does not respond. However, few reports on its operation and postoperative follow-up. We first present a case showing how the Zero-Profile implant system is utilized to treat dysphagia caused by noncontiguous anterior cervical osteophytes. CASE PRESENTATION: A patient with progressive dysphagia was referred to our department. Imaging examinations revealed a large diffuse idiopathic skeletal hyperostosis (DISH) related anterior osteophyte in C3/4, C6/7 and ossification of the anterior and posterior longitudinal ligaments. Anterior cervical osteophytectomy, discectomy, and fusion were performed on C3/4, C6/7. Two Zero-Profile implants were implanted. Postoperative dysphagia was significantly improved, and the patient was free to swallow large pills or solid foods at nine-years follow-up. CONCLUSION: Osteophyte excision can effectively treat esophageal cervical spondylosis, This case shows that fusion using the Zero-Profile implant system is a viable option for patients with potential cervical instability following osteophyte resection.

A meta-analysis comparing the short- and mid- to long-term outcomes of artificial cervical disc replacement(ACDR) with anterior cervical discectomy and fusion (ACDF) for the treatment of cervical degenerative disc disease.

PURPOSE: Anterior cervical discectomy and fusion (ACDF) surgery is commonly performed to treat cervical degenerative disc disease (CDDD). The lost of range of motion (ROM) is also found after ACDF, which contributes to degenerate in adjacent segment disease (ASD). Artificial cervical disc replacement (ACDR), an alternative to ACDF, is developed to preserve the ROM and reduce ASD. This article aims to compare the outcomes between ACDR and ACDF in the short-, mid-, and long-term. METHODS: Databases including Cochrane, Embase, PubMed, and Web of Science were searched. Only RCTs were included in this meta-analysis, and the search strategy followed the requirements of the Cochrane Handbook. The strength of evidence was assessed using GRADE. Two reviewers independently assessed the methodological quality of each included study and extracted the relevant data. RESULTS: Thirty prospective RCTs were included. Prolonged operative duration, better overall success, neurological success, and NDI success rates were found in ACDR group in all follow-up periods, with lower dysphagia/dysphonia during short-term follow-up. Moreover, a lower ASD was found in ACDR group during long-term follow-up and overall analysis, with lower reoperation rates in all follow-up periods. Comparable length of hospital stay and blood loss were found in both groups. Moreover, ASD was similar in short- and mid-term follow-ups, while dysphagia/dysphonia incidence was similar in mid- and long-term follow-ups. The incidence of implant events was comparable in all follow-up periods (p > 0.05). CONCLUSIONS: ACDR is as effective as ACDF and superior for some success rates. Disc replacement can reduce the risk of dysphagia/dysphonia, ASD, and re-operation.

Smartphone Positioning and Accuracy Analysis Based on Real-Time Regional Ionospheric Correction Model.

As one of the main errors that affects Global Navigation Satellite System (GNSS) positioning accuracy, ionospheric delay also affects the improvement of smartphone positioning accuracy. The current ionospheric error correction model used in smartphones has a certain time delay and low accuracy, which is difficult to meet the needs of real-time positioning of smartphones. This article proposes a method to use the real-time regional ionospheric model retrieved from the regional Continuously Operating Reference Stations (CORS) observation data to correct the GNSS positioning error of the smartphone. To verify the accuracy of the model, using the posterior grid as the standard, the electron content error of the regional ionospheric model is less than 5 Total Electron Content Unit (TECU), which is about 50% higher than the Klobuchar model, and to further evaluate the impact of the regional ionosphere model on the real-time positioning accuracy of smartphones, carrier-smoothing pseudorange and single-frequency Precise Point Positioning (PPP) tests were carried out. The results show that the real-time regional ionospheric model can significantly improve the positioning accuracy of smartphones, especially in the elevation direction. Compared with the Klobuchar model, the improvement effect is more than 34%, and the real-time regional ionospheric model also shortens the convergence time of the elevation direction to 1 min. (The convergence condition is that the range of continuous 20 s is less than 0.5 m).

ClC-3 promotes paclitaxel resistance via modulating tubulins polymerization in ovarian cancer cells.

Epithelial ovarian cancers (EOC) present as malignant tumors with high mortality in the female reproductive system diseases. Acquired resistance to paclitaxel (PTX), one of the first-line treatment of EOC, remains a therapeutic challenge. ClC-3, a member of the voltage-gated Cl- channels, plays an essential role in a variety of cellular activities, including chemotherapeutic resistance. Here, we demonstrated that the protein expression and channel function of ClC-3 was upregulated in PTX resistance A2780/PTX cells compared with its parental A2780 cells. The silence of ClC-3 expression by siRNA in A2780/PTX cells partly recovered the PTX sensitivity through restored the G2/M arrest and resumed the chloride channel blocked. ClC-3 siRNA both inhibited the expression of ClC-3 and ß-tubulin, whereas the ß-tubulin siRNA reduced the expression of itself only, without affecting the expression of ClC-3. Moreover, treatment of ClC-3 siRNA in A2780/PTX cells increased the polymerization ratio of ß-tubulin, and the possibility of proteins interaction between ClC-3 and ß-tubulin was existing. Take together, the over-expression of ClC-3 protein in PTX-resistance ovarian cancer cells promotes the combination of ClC-3 and ß-tubulin, which in turn increase the ration of free form and decrease the quota of the polymeric form of ß-tubulin, and finally reduce the sensitivity to PTX. Our findings elucidated a novel function of ClC-3 in regulating PTX resistance and ClC-3 could serve as a potential target to overcome the PTX resistance ovarian cancer.

The impact of COVID-19 on the Chinese stock market: Sentimental or substantial?

We investigate the impact of COVID-19 on Chinese stock market by an event study and examine the effect of individual investor sentiment on returns. The pandemic has an overall negative effect on stock market during the post-event window, which can't be explained by real losses. Results show a stronger positive correlation between individual investor sentiment and stock returns than usual. The impact on individual investor sentiment on stock returns is more significant for enterprises with high PB, PE and CMV, low net asset, and low institutional shareholding. Only 7 industries related to pharmacy, digitalization, and agriculture are boosted.

Estrogen Receptor alpha depletion affects the biomechanical properties and cytoskeleton rearrangements in breast cancer cells.

Estrogen Receptor alpha (ERα) affects the morphology of tumors, which is closely related to the biomechanical properties and the cytoskeletal proteins. In recent years, researchers have found that biomechanical properties and cytoskeletal proteins are closely related to the occurrence and development of tumors and that biomechanical properties can be used as markers for tumor development and drug resistance. The relationship between ERα expression status and biomechanical properties, cytoskeletal proteins is not known. In this study, we found that tamoxifen-resistant breast cancer cells (MCF-7/TamR) altered cell morphology and lacked of ERα expression during the process of the Tamoxifen resistance induction. To determine whether this change was influenced by ERα expression, we transiently constructed another ERα depleted model with ERα siRNA (MCF-7/ERα siRNA) and used atomic force microscope (AFM) to detect morphological and biophysical changes. The results indicated that the roughness and Young's modulus of ERα expression depleted cells were significantly increased, accompanied by rearrangement of the cytoskeletal proteins (F-actin, FLNA, α-tubulin) and the cytoskeletal regulatory protein Rho (Rac1, CDC42) decreased. Our results have demonstrated that ERα depletion affects the biomechanical properties of breast cancer cells, which are related to cytoskeletal protein rearrangement and Rho protein decreased.

Different properties between spontaneous and volume-activated chloride currents in human nasopharyngeal carcinoma and its normal counterpart cells.

Although the spontaneous chloride currents (SCC) have been well studied in the normal cells, its properties and roles in neoplasms cells are still unknown. Here, we found that the SCC was manifested in the poorly differentiated human nasopharyngeal carcinoma CNE-2Z cells, with some differences such as lower occurrence and bigger current density than those of the volume-activated chloride currents (VACC). NPPB, a chloride channel blocker, inhibited the SCC much stronger than the VACC. Down-regulation of chloride channel -3 (ClC-3), a volume and mechanically dependent ion channel, could significantly decrease the VACC, but not in SCC. The occurrence, latency, and mean density of the SCC were much lower in the normal nasopharyngeal NP69-SV40T cells than those in CNE-2Z cells. Our results demonstrated that the spontaneous electrical reactivity of neoplasm cells is higher than that of normal cells, which probably relates to their high physiological activity of neoplasm cells. SIGNIFICANCE OF THE STUDY: Spontaneous chloride currents (SCC) are well known in excitable tissues and regulate a variety of physiological and pathophysiological processes. During our researching on the volume-activated chloride currents (VACC) in human nasopharyngeal carcinoma CNE-2Z cells, SCC could be also observed with different properties from VACC. Meanwhile, the occurrence, latency, and mean density of the SCC were much higher in CNE-2Z cells than those in normal nasopharyngeal NP69-SV40T cells. Our results revealed the expression and characteristics of SCC in carcinoma cells and provided a preliminary experimental basis for further exploring the function of SCC in tumour cell biology.