Alterations of serine racemase expression determine proliferation and differentiation of neuroblastoma cells.

Although the role of serine racemase (SR) in neuropsychiatric disorders has been extensively studied, its role in cell proliferation and differentiation remains unclear. Deletion of Srr, the encoding gene for SR, has been shown to reduce dendritic arborization and dendritic spine density in the brains of adult mice, whereas increased SR levels have been associated with differentiation in cell cultures. Previously, we demonstrated that valproic acid induces differentiation in the N2A neuroblastoma cell line, and that this differentiation is associated with increased SR expression. These observations suggest that SR may have a role in cell proliferation and differentiation. We herein found that both valproic acid and all-trans retinoic acid induced N2A differentiation. In contrast, knockdown of SR reduced levels of differentiation, increased N2A proliferation, promoted cell cycle entry, and modulated expression of cell cycle-related proteins. To further evaluate the effects of SR expression on cell proliferation and differentiation, we used an in vivo model of neuroblastoma in nude mice. N2A cells stably expressing scramble shRNA (Srrwt -N2A) or specific Srr shRNA (Srrkd -N2A) were subcutaneously injected into nude mice. The weights and volumes of Srrwt -N2A-derived tumors were lower than Srrkd -N2A-derived tumors. Furthermore, Srrwt -N2A-derived tumors were significantly mitigated by intraperitoneal injection of valproic acid, whereas Srrkd -N2A-derived tumors were unaffected. Taken together, our findings demonstrate for the first time that alterations in SR expression determine the transition between proliferation and differentiation in neural progenitor cells. Thus, in addition to its well-established roles in neuropsychiatric disorders, our study has highlighted a novel role for SR in cell proliferation and differentiation.

The distal arthrogryposis-linked p.R63C variant promotes the stability and nuclear accumulation of TNNT3.

BACKGROUND: Distal arthrogryposis (DA) is comprised of a group of rare developmental disorders in muscle, characterized by multiple congenital contractures of the distal limbs. Fast skeletal muscle troponin-T (TNNT3) protein is abundantly expressed in skeletal muscle and plays an important role in DA. Missense variants in TNNT3 are associated with DA, but few studies have fully clarified its pathogenic role. METHODS: Sanger sequencing was performed in three generation of a Chinese family with DA. To determine how the p.R63C variant contributed to DA, we identified a variant in TNNT3 (NM_006757.4): c.187C>T (p.R63C). And then we investigated the effects of the arginine to cysteine substitution on the distribution pattern and the half-life of TNNT3 protein. RESULTS: The protein levels of TNNT3 in affected family members were 0.8-fold higher than that without the disorder. TNNT3 protein could be degraded by the ubiquitin-proteasome complex, and the p.R63C variant did not change TNNT3 nuclear localization, but significantly prolonged its half-life from 2.5 to 7 h, to promote its accumulation in the nucleus. CONCLUSION: The p.R63C variant increased the stability of TNNT3 and promoted nuclear accumulation, which suggested its role in DA.

The treatment of congenital pyriform sinus fistula: a single-center experience.

PURPOSE: Congenital pyriform sinus fistula (CPSF) often presents diagnosis and treatment challenges. This study aimed to explore the treatment principles and to evaluate the effectiveness of the hypothermia plasma cauterization with suspension laryngoscopy for CPSF. METHODS: The medical records of 56 patients with CPSF from January 2000 to December 2019 were retrospectively reviewed. RESULTS: Of the 56 cases, the lesions were predominantly located on the left side (95%), and the accuracy of the first diagnosis was 30%. Ultrasound showed an abnormal rate of 86%, while CT or MRI displayed an abnormal anatomic lesion of 92%. The 3D visual reconstruction enabled the analysis of morphological characteristics of CPSF. The positive predictive value of barium esophagography was 89%, whereas the positive rate of the internal opening in CPSF under local anesthesia laryngoscopy was 33%. Nine cases of sinus type underwent open resection, and the recurrence rate was 33%. Interestingly, ten patients with sinus type underwent hypothermia plasma cauterization with suspension laryngoscopy, leading to a success rate of 100% without apparent complications. CONCLUSIONS: Hypothermia plasma cauterization with suspension laryngoscopy alongside 3D imaging is both minimally invasive and repeatable with neglectable complications, which has the potential to serve as the first-line treatment for CPSF in the future.

Developing and validating a nomogram for early predicting the need for intestinal resection in pediatric intussusception.

Purpose: Develop and validate a nomogram for predicting intestinal resection in pediatric intussusception suspecting intestinal necrosis. Patients & methods: Children with intussusception were retrospectively enrolled after a failed air-enema reduction in the outpatient setting and divided into two groups: the intestinal resection group and the non-intestinal resection group. The enrolled cases were randomly selected for training and validation sets with a split ratio of 3:1. A nomogram for predicting the risk of intestinal resection was visualized using logistic regression analysis with calibration curve, C-index, and decision curve analysis to evaluate the model. Results: A total of 547 cases were included in the final analysis, of which 414 had non-intestinal necrosis and 133 had intestinal necrosis and underwent intestinal resection. The training set consisted of 411 patients and the validation cohort included 136 patients. Through forward stepwise regression, four variables (duration of symptoms, C-reaction protein, white blood cells, ascites) were selected for inclusion in the nomogram with a concordance index 0.871 (95% confidence interval: 0.834-0.908). Conclusion: We developed a nomogram for predicting intestinal resection in children with intussusception suspecting intestinal necrosis after a failed air-enema based on multivariate regression. This nomogram could be directly applied to facilitate predicting intestinal resection in pediatric intussusception suspecting necrosis.

Haemostatic indexes for predicting intestinal necrosis in children with intussusception.

BACKGROUND: To determine risk factors for intestinal necrosis in intussusception cases among children with failed non-surgical reduction for intussusception. METHODS: Totally, 540 hospitalized individuals with unsuccessful air-enema reduction in our hospital between November 2010 and November 2020 were assessed in this retrospective study. The 540 intussusception cases were divided into the intestinal necrosis and non-intestinal necrosis groups. Haemostatic parameters, demographic and clinical features were assessed. Predictors of intestinal necrosis were examined by univariable and multivariable logistic regression analyses. RESULTS: Of the 540 patients included, 113 showed intestinal necrosis. This intestinal necrosis group had a longer duration of symptom or length of illness, younger ages, higher platelet counts, fibrinogen amounts and d-dimer levels (all P = 0.000) compared with the non-intestinal necrosis group. Multivariable analysis revealed that duration of symptom (odds ratio (OR) 1.12; 95% confidence interval (CI) 1.16-1.23, P = 0.000), fibrinogen (OR 1.26; 95% CI 1.10-1.31, P = 0.010) and d-dimer (OR 2.07; 95% CI 1.91-2.28, P = 0.000) independently predicted intestinal necrosis in individuals undergoing surgical reduction for intussusception. Receiver operating characteristic curve analysis showed that d-dimer amounts had the largest area under the curve for predicting intestinal necrosis. CONCLUSION: On admission, long duration of symptom, high fibrinogen and d-dimer levels are critical risk factors for intestinal necrosis development in children with unsuccessful non-surgical reduction. d-Dimer levels have the best predictive value for intestinal necrosis.