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BACKGROUND: Astrocytes regulate blood-brain barrier (BBB) integrity, whereas subarachnoid haemorrhage (SAH) results in astrocyte dysregulation and BBB disruption. Here, we explored the involvement of tissue inhibitor of matrix metalloprotease-1 (TIMP1) in astrocyte-mediated BBB protection during SAH, along with its underlying mechanisms. METHODS: C57BL/6J mice were used to establish a model of SAH. The effects of TIMP1 on SAH outcomes were analysed by intraperitoneal injection of recombinant mouse TIMP1 protein (rm-TIMP1; 250 µg/kg). The roles of TIMP1 and its effector ß1-integrin on astrocytes were observed by in vivo transduction with astrocyte-targeted adeno-associated virus carrying TIMP1 overexpression plasmid or ß1-integrin RNAi. The molecular mechanisms underlying TIMP1 and ß1-integrin interactions were explored in primary cultured astrocytes stimulated with red blood cells (RBCs). RESULTS: TIMP1 was upregulated after SAH. Administration of rm-TIMP1 mitigated SAH-induced early brain injury (EBI) in male and female mice. TIMP1 was primarily expressed in astrocytes; its overexpression in astrocytes led to increased ß1-integrin expression in astrocytes, along with the preservation of astrocytic endfoot attachment to the endothelium and subsequent recovery of endothelial tight junctions. All of these effects were reversed by the knockdown of ß1-integrin in astrocytes. Molecular analysis showed that TIMP1 overexpression decreased the RBC-induced ubiquitination of ß1-integrin; this effect was partially achieved by inhibiting the interaction between ß1-integrin and the E3 ubiquitin ligase Trim21. CONCLUSION: TIMP1 inhibits the interaction between ß1-integrin and Trim21 in astrocytes, thereby rescuing the ubiquitination of astrocytic ß1-integrin. It subsequently restores interactions between astrocytic endfeet and the endothelium, as well as BBB integrity, eventually mitigating SAH-induced EBI.
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Accumulating evidence suggests that changes in the tumor microenvironment caused by radiotherapy are closely related to the recurrence of glioma. However, the mechanisms by which such radiation-induced changes are involved in tumor regrowth have not yet been fully investigated. In the present study, how cranial irradiation-induced senescence in non-neoplastic brain cells contributes to glioma progression is explored. It is observed that senescent brain cells facilitated tumor regrowth by enhancing the peripheral recruitment of myeloid inflammatory cells in glioblastoma. Further, it is identified that astrocytes are one of the most susceptible senescent populations and that they promoted chemokine secretion in glioma cells via the senescence-associated secretory phenotype. By using senolytic agents after radiotherapy to eliminate these senescent cells substantially prolonged survival time in preclinical models. The findings suggest the tumor-promoting role of senescent astrocytes in the irradiated glioma microenvironment and emphasize the translational relevance of senolytic agents for enhancing the efficacy of radiotherapy in gliomas.
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Neoplasias Encefálicas , Glioblastoma , Glioma , Humanos , Glioblastoma/genética , Astrocitos/patología , Senoterapéuticos , Neoplasias Encefálicas/genética , Línea Celular Tumoral , Microambiente TumoralRESUMEN
BACKGROUND: Ubiquitination plays an important role in proliferating and invasive characteristic of glioblastoma (GBM), similar to many other cancers. Tripartite motif 25 (TRIM25) is a member of the TRIM family of proteins, which are involved in tumorigenesis through substrate ubiquitination. METHODS: Difference in TRIM25 expression levels between nonneoplastic brain tissue samples and primary glioma samples was demonstrated using publicly available glioblastoma database, immunohistochemistry, and western blotting. TRIM25 knockdown GBM cell lines (LN229 and U251) and patient derived GBM stem-like cells (GSCs) GBM#021 were used to investigate the function of TRIM25 in vivo and in vitro. Co-immunoprecipitation (Co-IP) and mass spectrometry analysis were performed to identify NONO as a protein that interacts with TRIM25. The molecular mechanisms underlying the promotion of GBM development by TRIM25 through NONO were investigated by RNA-seq and validated by qRT-PCR and western blotting. RESULTS: We observed upregulation of TRIM25 in GBM, correlating with enhanced glioblastoma cell growth and invasion, both in vitro and in vivo. Subsequently, we screened a panel of proteins interacting with TRIM25; mass spectrometry and co-immunoprecipitation revealed that NONO was a potential substrate of TRIM25. TRIM25 knockdown reduced the K63-linked ubiquitination of NONO, thereby suppressing the splicing function of NONO. Dysfunctional NONO resulted in the retention of the second intron in the pre-mRNA of PRMT1, inhibiting the activation of the PRMT1/c-MYC pathway. CONCLUSIONS: Our study demonstrates that TRIM25 promotes glioblastoma cell growth and invasion by regulating the PRMT1/c-MYC pathway through mediation of the splicing factor NONO. Targeting the E3 ligase activity of TRIM25 or the complex interactions between TRIM25 and NONO may prove beneficial in the treatment of GBM.
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Glioblastoma , Factores de Transcripción , Proteínas de Motivos Tripartitos , Humanos , Línea Celular Tumoral , Proliferación Celular , Proteínas de Unión al ADN/genética , Regulación Neoplásica de la Expresión Génica , Glioblastoma/metabolismo , Glioblastoma/patología , Proteína-Arginina N-Metiltransferasas/genética , Proteína-Arginina N-Metiltransferasas/metabolismo , Proteínas Represoras/metabolismo , Factores de Empalme de ARN/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , UbiquitinaciónRESUMEN
Matricellular proteins are nonstructural extracellular matrix components that are expressed at low levels in normal adult tissues and are upregulated during development or under pathological conditions. Tenascin C (TNC), a matricellular protein, is a hexameric and multimodular glycoprotein with different molecular forms that is produced by alternative splicing and post-translational modifications. Malignant gliomas are the most common and aggressive primary brain cancer of the central nervous system. Despite continued advances in multimodal therapy, the prognosis of gliomas remains poor. The main reasons for such poor outcomes are the heterogeneity and adaptability caused by the tumor microenvironment and glioma stem cells. It has been shown that TNC is present in the glioma microenvironment and glioma stem cell niches, and that it promotes malignant properties, such as neovascularization, proliferation, invasiveness, and immunomodulation. TNC is abundantly expressed in neural stem cell niches and plays a role in neurogenesis. Notably, there is increasing evidence showing that neural stem cells in the subventricular zone may be the cells of origin of gliomas. Here, we review the evidence regarding the role of TNC in glioma progression, propose a potential association between TNC and gliomagenesis, and summarize its clinical applications. Collectively, TNC is an appealing focus for advancing our understanding of gliomas.
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Enzymatic hydrolysis of sugar beets for achieving liquefaction and sugar release is a critical step for beet-ethanol production. An enzyme recycling process was developed in this study to reduce the economic uncertainty raised by the high costs of enzymes by reducing the fresh enzyme usage. A mixture of cellulases and pectinases was used in the beet hydrolysis. The hydrolysate was centrifuged and then processed through a 50 kDa molecular weight cut-off polyethersulfone membrane to recover enzymes from the liquid. Liquid enzyme recycling with 50% fresh enzyme addition achieved a similar liquefaction extent and sugar yield compared to the positive control with 100% fresh enzyme. Solid enzyme recycling showed a lower liquefaction efficiency, requiring at least 75% of fresh enzyme addition for a comparable liquefaction extent. Five sequential batches of hydrolysis with liquid enzyme recycling were successfully conducted to hydrolyze sugar beets with similar liquefaction extents and sugar yields.
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Beta vulgaris , Celulasas , Carbohidratos , Hidrólisis , AzúcaresRESUMEN
Background: Transsphenoidal surgery (TSS) is first-line treatment for giant pituitary adenomas (PAs). Although PA is a benign neuroendocrine tumor that originates from adenohypophysial cells, the surgical outcomes and prognosis of giant PAs differ significantly due to multiple factors such as tumor morphology, invasion site, pathological characteristics and so on. The aim of this study was to evaluate surgical outcomes of giant PAs in a single-center cohort. Methods: The clinical features and outcomes of 239 patients with giant PA who underwent sphenoidal surgery at the Second Affiliated Hospital of Zhejiang University School of Medicine from January 2015 to October 2021 were collected from medical records. The basic clinical information (age, gender, function etc.), surgical procedure, imaging features (maximum diameter, invasion characteristics, tumor shape etc.) and histopathological characteristics (pathological results, Ki-67, P53 etc.) were retrospectively reviewed. SPSS 25.0 and Stata 12.0 software were used for statistical analysis. Results: A total of 239 patients with giant PAs underwent TSS, of which 168 surgeries (70.29%) were endoscopic endonasal transsphenoidal (EETS) and 71 (29.71%) were microscopic transsphenoidal (MTS). The mean preoperative maximum diameter in the cohort was 45.64 mm. Gross-total resection was achieved in 46 patients (19.25%), near-total in 56 (23.43%), subtotal in 68 (28.45%), and partial in 69 (28.87%) patients. The maximum tumor diameter and Knosp grade were the significant factors that limited the extent of the resection of giant PAs. A total of 193 patients (80.75%) experienced surgical complications, and the most common complications were postoperative diabetes insipidus (DI) (91, 38.08%), intracranial infection (36, 15.06%) and cerebrospinal fluid (CSF) leaks (37, 15.48%). In addition, there was a significant difference in the incidence of CSF leaks between the neuroendoscopy group and the microscopic group (P < 0.05). Conclusion: The management of giant PAs remains a therapeutic challenge due to their large size and postoperative complications. The maximum diameter and Knosp grade of giant PAs significantly limited the extent of resection, which warrants a reasonable surgical plan.
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Adenoma , Neoplasias Hipofisarias , Adenoma/patología , Humanos , Procedimientos Neuroquirúrgicos/métodos , Neoplasias Hipofisarias/patología , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Clinically, the low expression of wild-type aryl hydrocarbon receptor-interacting protein (AIP) in patients with sporadic growth hormone (GH)-secreting pituitary adenoma (GHPA) is associated with a more aggressive phenotype. However, the mechanism by which AIP expression is regulated in GHPA remains unclear. Herein, we investigated a transcription factor that regulates AIP expression and explored its role in tumor phenotypes. METHODS: General transcription factor IIB (GTF2B) was predicted by several bioinformatic tools to regulate AIP expression transcriptionally. Regulation by GTF2B was evaluated using chromatin immunoprecipitation (ChIP), reverse transcription PCR, luciferase reporter, and western blot experiments in SH-SY5Y cells. Furthermore, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, transwell invasive assay, ELISA, western blot, immunohistochemical staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling were performed to investigate the effects of GTF2B and AIP on tumor cell proliferation, apoptosis, growth hormone secretion, and invasiveness in GH3 cells and mouse xenograft models. Moreover, correlations between GTF2B and AIP expression were explored in GHPA cases. RESULTS: ChIP and luciferase reporter studies demonstrated that the regulation of AIP expression by GTF2B was dependent on the intergenic-5' untranslated region element of AIP and the initial residual S65 of GTF2B. In vitro and in vivo experiments indicated that GTF2B regulated AIP expression to impact the GHPA phenotype; this was confirmed by data from 33 GHPA cases. CONCLUSIONS: We determined the regulation by GTF2B of AIP transcription in GHPA and its impact on tumor phenotype. Our findings suggest that GTF2B may be a potential therapeutic target for GHPA with low AIP expression.
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Adenoma Hipofisario Secretor de Hormona del Crecimiento , Péptidos y Proteínas de Señalización Intracelular/genética , Neoplasias Hipofisarias , Factor de Transcripción TFIIB , Animales , Línea Celular Tumoral , Adenoma Hipofisario Secretor de Hormona del Crecimiento/genética , Adenoma Hipofisario Secretor de Hormona del Crecimiento/metabolismo , Humanos , Ratones , Neoplasias Hipofisarias/tratamiento farmacológicoRESUMEN
Background: Pituitary adenoma (PA) is a benign neuroendocrine tumor caused by adenohypophysial cells, and accounts for 10%-20% of all primary intracranial tumors. The surgical outcomes and prognosis of giant pituitary adenomas measuring ≥3 cm in diameter differ significantly due to the influence of multiple factors such as tumor morphology, invasion site, pathological characteristics and so on. The aim of this study was to explore the risk factors related to the recurrence or progression of giant and large PAs after transnasal sphenoidal surgery, and develop a predictive model for tumor prognosis. Methods: The clinical and follow-up data of 172 patients with large or giant PA who underwent sphenoidal surgery at the Second Affiliated Hospital of Zhejiang University School of Medicine from January 2011 to December 2017 were retrospectively analyzed. The basic clinical information (age, gender, past medical history etc.), imaging features (tumor size, invasion characteristics, extent of resection etc.), and histopathological characteristics (pathological results, Ki-67, P53 etc.) were retrieved. SPSS 21.0 software was used for statistical analysis, and the R software was used to establish the predictive nomogram. Results: Seventy out of the 172 examined cases (40.7%) had tumor recurrence or progression. The overall progress free survival (PFS) rates of the patients at 1, 3 and 5 years after surgery were 90.70%, 79.65% and 59.30% respectively. Log-rank test indicated that BMI (P < 0.001), Knosp classification (P < 0.001), extent of resection (P < 0.001), Ki-67 (P < 0.001), sphenoidal sinus invasion (P = 0.001), Hardy classification (P = 0.003) and smoking history (P = 0.018) were significantly associated with post-surgery recurrence or progression. Cox regression analysis further indicated that smoking history, BMI ≥25 kg/m2, Knosp classification grade 4, partial resection and ≥3% Ki-67 positive rate were independent risk factors of tumor recurrence or progression (P < 0.05). In addition, the nomogram and ROC curve based on the above results indicated significant clinical value. Conclusion: The postoperative recurrence or progression of large and giant PAs is related to multiple factors and a prognostic nomogram based on BMI (≥25 kg/m2), Knosp classification (grade 4), extent of resection (partial resection) and Ki-67 (≥3%) can predict the recurrence or progression of large and giant PAs after transnasal sphenoidal surgery.
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Adenoma/cirugía , Progresión de la Enfermedad , Recurrencia Local de Neoplasia/diagnóstico , Nomogramas , Neoplasias Hipofisarias/cirugía , Seno Esfenoidal/cirugía , Adenoma/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Hipofisarias/diagnóstico , Pronóstico , Estudios Retrospectivos , Resultado del Tratamiento , Adulto JovenRESUMEN
OBJECTIVE: The aim of present report was to elucidate the effect of cell division cycle associated 4 (CDCA4) on the proliferation and apoptosis of Wilm's tumor cells, and to further evaluate its underlying mechanism. METHODS: The expression profiles of CDCA4 and clinical information of Wilm's tumor patients were obtained from public Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database portal. Real-time qPCR and western blot analyses were utilized to determine the expression levels of CDCA4. Gain- and loss-of-function of CDCA4 assays were conducted with transfection technology to investigate the biological role of CDCA4 in Wilm's tumor cells. Cell counting kit 8 and flow cytometer assays were employed to examine the effect of CDCA4 on the cells proliferation and apoptosis. Protein expression levels of indicated markers in each group of Wilm's tumor cells were measured by western blot. RESULTS: The transcriptional expression of CDCA4 was drastically upregulated in Wilm's tumor tissues according to the public TARGET database and in Wilm's tumor cells. The cells viability was remarkably reduced whereas the cells apoptosis was increased in CDCA4-knockdown group compared with negative control group. However, CDCA4-overexpression group promoted the cells proliferation and suppressed the cells apoptosis. Furthermore, the protein expression levels of p-AKT, p-mTOR, and Cyclin D1 were significantly reduced after depletion of CDCA4, whereas overexpression of CDCA4 dramatically elevated these markers' expression levels. CONCLUSIONS: CDCA4 is highly expressed in Wilm's tumor and promoted the proliferation whereas inhibited the apoptosis of Wilm's tumor cells through activating the AKT/mTOR signaling pathway.
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Apoptosis , Proteínas de Ciclo Celular/metabolismo , Neoplasias Renales/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Tumor de Wilms/metabolismo , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Proliferación Celular/genética , Supervivencia Celular/genética , Ciclina D1/metabolismo , Humanos , Neoplasias Renales/genética , Neoplasias Renales/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Tumor de Wilms/genética , Tumor de Wilms/patologíaRESUMEN
AIM: To demonstrate the clinical value of epithelial membrane protein 3 (EMP3) with bioinformatic analysis and clinical data, and then to establish a practical nomogram predictive model with bicenter validation. METHODS: The data from CGGA and TCGA database were used to analyze the expression of EMP3 and its correlation with clinical prognosis. Then, we analyzed EMP3 expression in samples from 179 glioma patients from 2013 to 2017. Univariate and multivariate cox regression were used to predict the prognosis with multiple factors. Finally, a nomogram to predict poor outcomes was formulated. The accuracy and discrimination of nomograms were determined with ROC curve and calibration curve in training and validation cohorts. RESULTS: EMP3 was significantly higher in higher-grade glioma and predicted poor prognosis. In multivariate analysis, high expression of EMP3 (HR = 2.842, 95% CI 1.984-4.071), WHO grade (HR = 1.991, 95% CI 1.235-3.212), and IDH1 mutant (HR = 0.503, 95% CI 0.344-0.737) were included. The nomogram was constructed based on the above features, which represented great predictive value in clinical outcomes. CONCLUSION: This study demonstrated EMP3 as a novel predictor for clinical progression and clinical outcomes in glioma. Moreover, the nomogram with EMP3 expression represented a practical approach to provide individualized risk assessment for glioma patients.
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Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Glioma/genética , Glioma/terapia , Glicoproteínas de Membrana/genética , Nomogramas , Adulto , Anciano , Algoritmos , Biomarcadores de Tumor , Bases de Datos Genéticas , Femenino , Humanos , Isocitrato Deshidrogenasa/genética , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Curva ROC , Medición de Riesgo , Análisis de Supervivencia , Resultado del Tratamiento , Adulto JovenRESUMEN
AIMS: Deep burn-wounds undergo a dynamic progression in the initial or periburn area after insults, and the zone of stasis is the crucial region suffering the deterioration, considered as salvageable. Few studies explored the role of mitochondria in this process. This study is to clarify a possible "built-in" protection of mitophagy. MAIN METHODS: A classic "comb" scald rat model was established. Histological and blood-flow observation were processed based on hematoxylin-eosin staining and laser analysis. Oxidative and apoptotic status were analyzed by commercial kits. Transmission-electron microscope, immunofluorescence staining, and western blot were applied to detect the mitophagy in the zone of stasis and potential regulators. Adenovirus-based gene-silence contributed to determine the role of HIF-1α as a regulatory mediator. KEY FINDINGS: We found that burn-caused typical ischemia and histological deterioration in the zone of stasis, in parallel with increases in oxidative stress and apoptosis. Mitochondrial damage was involved in the aforementioned changes. Furthermore, we detected mitophagy in burn-wounds, which was contradictory to the burn-wound conversion. HIF-1α expression was closely related to the level of mitophagy, while BNIP3 and PARKIN are involved downstream. SIGNIFICANCE: We demonstrate that burn-induced mitochondrial impairment contributes to the mobilization of injurious mechanisms in the zone of stasis and that mitophagy provides a beneficial way to protect against burn-wound progression via the elimination of damaged mitochondria. Our findings offer insights into mitochondrial quality control in burn-wound progression and suggest the novel concept that HIF-1α may be a therapeutic target due to its possible regulation on BNIP3- or PARKIN-mediated mitophagy.
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Apoptosis , Quemaduras/prevención & control , Mitocondrias/patología , Mitofagia , Estrés Oxidativo , Sustancias Protectoras , Cicatrización de Heridas , Animales , Quemaduras/patología , Masculino , Mitocondrias/metabolismo , Ratas , Ratas Sprague-Dawley , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
BACKGROUND: Isolated onset of intracranial hypertension due to spinal cord tumor is rare, thus, easily leading to misdiagnosis and delay in effective treatment. CASE PRESENTATION: Herein, we describe a 45-year-old female patient who manifested isolated symptoms and signs of intracranial hypertension and whose condition was initially diagnosed as idiopathic intracranial hypertension and transverse sinus stenosis. The patient received a stent implantation; however, no improvements were observed. One year later her symptoms exacerbated, and during rehospitalization a spinal imaging examination revealed a lumbar tumor. Pathologic evaluation confirmed schwannoma, and tumor resection significantly improved her symptoms, except for poor vision. CONCLUSIONS: Space-occupying lesions of the spine should be considered in the differential diagnosis of idiopathic intracranial hypertension, even in the absence of spine-localized signs or symptoms.
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Hipertensión Intracraneal/etiología , Neurilemoma/complicaciones , Neurilemoma/diagnóstico , Seudotumor Cerebral/diagnóstico , Neoplasias de la Médula Espinal/complicaciones , Neoplasias de la Médula Espinal/diagnóstico , Errores Diagnósticos , Femenino , Humanos , Hipertensión Intracraneal/diagnóstico , Persona de Mediana EdadRESUMEN
Mitochondria are highly dynamic organelles which are joined by mitochondrial fusion and divided by mitochondrial fission. The balance of mitochondrial fusion and fission plays a critical role in maintaining the normal function of neurons, of which the processes are both mediated by several proteins activated by external stimulation. Cerebral ischemia-reperfusion (I/R) injury can disrupt the balance of mitochondrial fusion and fission through regulating the expression and post-translation modification of fusion- and fission-related proteins, thereby destroying homeostasis of the intracellular environment and causing neuronal death. Furthermore, human intervention in fusion- and fission-related proteins can influence the function of neurons and change the outcomes of cerebral I/R injury. In recent years, researchers have found that mitochondrial dysfunction was one of the main factors involved in I/R, and mitochondria is an attractive target in I/R neuroprotection. Therefore, mitochondrial-targeted therapy of the nervous system for I/R gradually started from basic study to clinical application. In the present review, we highlight recent progress in mitochondria fusion and fission in neuronal death induced by cerebral I/R to help understanding the regulatory factors and signaling networks of aberrant mitochondrial fusion and fission contributing to neuronal death during I/R, as well as the potential neuroprotective therapeutics targeting mitochondrial dynamics, which may help clinical treatment and development of relevant dugs.
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Isquemia Encefálica/patología , Dinámicas Mitocondriales , Neuronas/patología , Daño por Reperfusión/patología , Animales , Autofagia , Muerte Celular , HumanosRESUMEN
BACKGROUND AND PURPOSE: The aim of this study is to identify the early predictors for delayed cerebral ischemia (DCI) and develop a risk stratification score by focusing on the early change after aneurysmal subarachnoid hemorrhage (aSAH). METHODS: The study retrospectively reviewed aSAH patients between 2014 and 2015. Risk factors within 72 hours after aSAH were included into univariable and multivariable logistic regression analysis to screen the independent predictors for DCI and to design a risk stratification score. RESULTS: We analyzed 702 aSAH patients; four predictors were retained from the final multivariable analysis: World Federation of Neurosurgical Societies scale (WFNS; OR = 4.057, P < .001), modified Fisher Scale (mFS; OR = 2.623, P < .001), Subarachnoid Hemorrhage Early Brain Edema Score (SEBES; OR = 1.539, P = .036), and intraventricular hemorrhage (IVH; OR = 1.932, P = .002). According to the regression coefficient, we created a risk stratification score ranging from 0 to 7 (WFNS = 3, mFS = 2, SEBES = 1, and IVH = 1). The new score showed a significantly higher area under curve (0.785) compared with other scores (P < .001). CONCLUSION: The early DCI score provides a practical method at the early 72 hours after aSAH to predict DCI.
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Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/fisiopatología , Hemorragia Subaracnoidea/diagnóstico por imagen , Hemorragia Subaracnoidea/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Factores de Riesgo , Factores de TiempoRESUMEN
Poly (vinyl alcohol-co-ethylene) nanofibrous membranes (PVA-co-PE NFM) were successfully modified by sodium-3-sulfobenzoate to become negatively charged with sulfonate groups, and the sulfonated (PVA-co-PE) nanofiber membrane SS (PVA-co-PE NFM) was used in non-covalent adsorption of cellulases via electrostatic attraction. The modified NFM showed excellent adsorption to the enzyme molecules due to the incorporated static charge interaction with the fibers, high open-porosity and ultrahigh surface areas of the nanofibers. Such unique morphology and chemical structures lead to the adsorption capacity of 130â¯mgâ¯g-1 and reusability for 5 cycles without significant change in catalytic functions. The morphology changes of the nanofibrous membranes were observed by using a scanning electron microscopy, and chemical structures of the membranes were characterized by using FTIR and water contact angle measurements. SS (PVA-co-PE NFM) is a promising solid support media for enzyme immobilization, and the immobilized enzymes can be applied in industrial applications.
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Celulasa/química , Celulasa/aislamiento & purificación , Equipo Reutilizado , Nanofibras/química , Polivinilos/química , Ácidos Sulfónicos/química , Adsorción , Aniones/química , Estructura Molecular , Tamaño de la Partícula , Reciclaje , Propiedades de SuperficieRESUMEN
In this paper, the hydroxyl groups on the surface of graphene oxide (GO) were used to initiate the ring-opening polymerization of a lactic acid O-carboxyanhydride. GO grafted with poly (l-lactic acid) molecular chains (GO-g-PLLA) was prepared. Lactic acid O-carboxyanhydride has a higher polymerization activity under mild polymerization conditions. Thus, the functionalization of the polymer chains and obtaining poly (lactic acid) (PLLA) was easily achieved by ring-opening polymerization with 4-dimethylaminopyridine (DMAP) as the catalyst. The results showed that with this method, PLLA can be rapidly grafted to the surface of GO in one step. As a result, the chemical structure of the GO surface was altered, improving its dispersion in organic solvents and in a PLLA matrix, as well as its bonding strength with the PLLA interface. We then prepared GO/PLLA and PLLA/GO-g-PLLA composite materials and investigated the differences in their interfacial properties and mechanical properties. GO-g-PLLA exhibited excellent dispersion in the PLLA matrix and formed excellent interfacial bonds with PLLA through mechanical interlocking, demonstrating a significant enhancement effect compared to PLLA. The water vapor and oxygen permeabilities of the GO-g-PLLA/PLLA composite decreased by 19% and 29%, respectively.