Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
País de afiliación
Intervalo de año de publicación
1.
Ann Hematol ; 103(4): 1197-1209, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38329487

RESUMEN

Venetoclax (VEN), a BCL-2 inhibitor, has transformed treatment strategies for elderly and unfit acute myeloid leukemia (AML) patients by significantly improving response rates and survival. However, the predictive factors for VEN efficacy differ from traditional chemotherapy. The clinical relevance of the FAB (French-American-British) monocytic subtype, including M4 and M5, has been debated as a marker for VEN resistance. This real-world study examined 162 newly diagnosed (ND) and 85 relapsed/refractory (R/R) AML patients who received VEN-based therapy at West China Hospital, Sichuan University, from January 2019 to January 2023. We retrospectively collected clinical and treatment data from electronic medical records. The median age of the cohort was 55.5 years (range: 16.5-83.5). The composite complete remission (cCR) rate in the entire cohort was 60.7%. Specifically, among newly diagnosed (ND) patients, FAB monocytic subtypes exhibited lower cCR compared to non-monocytic subtypes (55.1% vs. 76.3%, P = 0.007). Additionally, there were no significant differences observed between M4 and M5 subtypes, both in the ND group (61.7% vs. 40.9%, p = 0.17) and the R/R group (38.2% vs. 40%, p > 0.9). Furthermore, the median follow-up was 238 (range: 7-1120) days. ND patients with monocytic subtypes had shorter overall survival compared to non-monocytic subtypes (295 days vs. not reached, p = 0.0017). Conversely, R/R patients showed no such difference (204 vs. 266 days, p = 0.72). In summary, our study suggests that the FAB monocytic subtype can predict VEN resistance and shorter survival in ND AML patients. Moreover, there is no significant distinction between M4 and M5 subtypes.


Asunto(s)
Leucemia Mieloide Aguda , Humanos , Anciano , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Anciano de 80 o más Años , Estudios Retrospectivos , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Sulfonamidas/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico
2.
Ann Hematol ; 102(7): 1695-1704, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37166528

RESUMEN

All-trans retinoic acid (ATRA) application is a novel treatment approach for primary immune thrombocytopenia (ITP). This study aimed to evaluate the efficacy and safety of ATRA in the treatment of ITP. The databases of PubMed (MEDLINE), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and China National Knowledge Internet were searched on August 5, 2022, to find randomized controlled trials (RCTs) and observational studies. Five observational studies and four RCTs from China were included, and 760 Chinese patients were analyzed. In the five observational studies, the pooled overall response rate (ORR) and complete response rate (CRR) were 59.5% (95% confidence interval [CI], 52.4-66.4%) and 20.6% (95% CI, 14.3-27.6%), respectively. In the selected four RCTs, the pooled odds ratios for sustained response rate, ORR, and CRR were 3.00 (95% CI, 1.97-4.57; P < 0.01), 3.21 (95% CI, 2.15-4.78; P < 0.01), and 2.12 (95% CI, 1.17-3.86; P = 0.01), respectively. ATRA was associated with a reduction in relapse rate and salvage treatment rate (odds ratio, 0.30; 95% CI, 0.18-0.50; P < 0.01; 0.36; 95% CI, 0.23-0.56; P < 0.01, respectively). The pooled odds ratios for grade 1-2 dry skin, headache (or dizziness), and rash acneiform were 49.99 (95% CI, 16.05-155.67; P < 0.01), 1.75 (95% CI, 0.98-3.12; P = 0.06), and 0.37 (95% CI, 0.10-1.34; P = 0.13), respectively. This study suggests that ATRA may significantly improve the initial and long-term response of patients with ITP.


Asunto(s)
Púrpura Trombocitopénica Idiopática , Humanos , Tretinoina , Enfermedad Crónica , Inducción de Remisión , China
3.
Molecules ; 28(23)2023 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-38067480

RESUMEN

Advances in nanotechnology have brought innovations to cancer therapy. Nanoparticle-based anticancer drugs have achieved great success from bench to bedside. However, insufficient therapy efficacy due to various physiological barriers in the body remains a key challenge. To overcome these biological barriers and improve the therapeutic efficacy of cancers, multistage self-assembled nanomaterials with advantages of stimuli-responsiveness, programmable delivery, and immune modulations provide great opportunities. In this review, we describe the typical biological barriers for nanomedicines, discuss the recent achievements of multistage self-assembled nanomaterials for stimuli-responsive drug delivery, highlighting the programmable delivery nanomaterials, in situ transformable self-assembled nanomaterials, and immune-reprogramming nanomaterials. Ultimately, we perspective the future opportunities and challenges of multistage self-assembled nanomaterials for cancer immunotherapy.


Asunto(s)
Nanopartículas , Nanoestructuras , Neoplasias , Humanos , Nanoestructuras/uso terapéutico , Nanopartículas/uso terapéutico , Sistemas de Liberación de Medicamentos , Neoplasias/tratamiento farmacológico , Inmunoterapia
4.
Pharm Dev Technol ; 27(5): 503-510, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35653620

RESUMEN

The aim of the present study was to develop Poly (lactic-co-glycolic acid) (PLGA)-based microspheres containing ropivacaine and betamethasone (RPC/BTM PLGA MS) by emulsion-solvent evaporation method. RPC/BTM PLGA MS were characterized by physical properties, such as morphology and particle size, and in vitro drug release. In addition, in vivo pharmacokinetics and pharmacodynamics of RPC/BTM PLGA MS were also investigated. The prepared RPC/BTM PLGA MS was suitable for local injection with a well-dispersed spherical shape, high stability, and high encapsulation efficiency. The mean diameter was 14.8 ± 1.2 µm and the polydispersity index (PDI) was 0.32 ± 0.04. In an in vitro study of drug release, it can be concluded that the RPC/BTM PLGA MS exhibited sustained and long-term release properties for 16 days. Furthermore, the result of an in vivo study indicated that the RPC/BTM PLGA MS had sustained release effect and the pharmacodynamics result showed that preparing RPC/BTM PLGA MS as microsphere preparation could not only extend the drug effect time but also prolong the duration of local anesthetics compared with the common RPC PLGA MS.


Asunto(s)
Betametasona , Nervio Ciático , Animales , Ratones , Microesferas , Tamaño de la Partícula , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ropivacaína
5.
Int J Mol Sci ; 19(9)2018 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-30217013

RESUMEN

In this study, composite films of stearic acid⁻modified magnesium oxide whiskers (Sa⁻w-MgO)/poly-l-lactic acid (PLLA) were prepared through solution casting, and the in vitro degradation properties and cytocompatibility of the composites with different whisker contents were investigated. The results showed that the degradation behavior of the composite samples depended significantly on the whisker content, and the degradation rate increased with the addition of MgO content. Furthermore, the degradation of the composites with higher contents of whiskers was influenced more severely by the hydrophilicity and pH value, leading to more final weight loss, but the decomposition rate decreased gradually. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO whiskers through neutralization of the acidic product of PLLA degradation. The cytocompatibility of the composites also increased remarkably, as determined from the cell viability results, and was higher than that of PLLA at the chosen whisker content. This was beneficial for the cell affinity of the material, as it notably led to an enhanced biocompatibility of the PLLA, in favor of promoting cell proliferation, which significantly improved its bioactivity, as well.


Asunto(s)
Óxido de Magnesio/química , Poliésteres/química , Materiales Biocompatibles/química , Concentración de Iones de Hidrógeno , Ensayo de Materiales
6.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 49(1): 145-147, 2018 Jan.
Artículo en Zh | MEDLINE | ID: mdl-29737107

RESUMEN

OBJECTIVE: To analyze the clinical features,response to therapy and prognosis of intravascular large B-cell lymphoma (IVLBCL). METHODS: The clinical data of 17 cases with IVLBCL were retrospectively reviewed,and survival analysis was conducted. RESULTS: The study involved 10 males and 7 females of IVLBCL with a mean age of 53 years old. The most common symptom of the disease was recurrent fever (76.5%). The lymphoma was mainly observed in bone marrow (64.7%) and was clinically determined as stage ⅣB (70.6%). Many of the patients were also diagnosed with the hemophagocytic syndrome (29.4%). R-CHOP (rituximab,cyclophosphamide,epirubicin,vindesine,prednisone) or CHOP regimen chemotherapy significantly improved the survival of the patients (P=0.000 2). Unfortunately,those patients with bone marrow involvement were prone to relapse after treatment. CONCLUSION: IVLBCL is highly invasive and associated with poor prognosis. R-CHOP chemotherapy can significantly improve the prognosis.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Linfoma de Células B Grandes Difuso/diagnóstico , Linfoma de Células B Grandes Difuso/terapia , Anticuerpos Monoclonales de Origen Murino/uso terapéutico , Ciclofosfamida/uso terapéutico , Doxorrubicina/uso terapéutico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Prednisona/uso terapéutico , Pronóstico , Estudios Retrospectivos , Rituximab , Vincristina/uso terapéutico
7.
J Nanosci Nanotechnol ; 17(2): 983-99, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29671949

RESUMEN

In recent years, chemotherapy targeting cancer stem cells has increasingly garnered interest from the scientists and clinicians. In this study, we explored both in vitro and in vivo if a chemotherapy regimen could arrest gastric tumor growth via demolishing CD24+ and CD44+ cancer stem cells (CSC) in the tumor mass. To facilitate the tumorigenesis in the subcutaneous xenograft model, we employed an electrospun scaffold comprising polydioxanone and gelatin for the delivery of tumor cells. The scaffold sported a highly porous micro-structure and promoted the in vitro and in vivo tumorigenesis without inducing apoptosis. in vivo studies confirmed that the tumor enjoyed an increase of volume by 56.21% and weight by 71.29%, respectively, in a 12-week period. Interestingly, populations of CD24+ and CD44+ cells in the tumor increased by 37% and 274%, respectively. No phenotypic change during tumorigenesis was observed due to the presence of the scaffold. Thereafter, we studied the chemotherapeutic effectiveness of a regimen comprising docetaxel, cisplatin and fluorouracil (DCF) in the scaffold model. The study showed that this regimen demonstrated a strong capability to demolish the CD44+ subpopulation in the tumor. This discovery warrants further study of the DCF regimen for gastric cancer. Moreover, the scaffold offers cancer scientists an accelerated in vivo platform for mechanistic chemotherapy study.


Asunto(s)
Antineoplásicos/farmacología , Cisplatino/farmacología , Fluorouracilo/farmacología , Células Madre Neoplásicas/efectos de los fármacos , Neoplasias Gástricas/metabolismo , Taxoides/farmacología , Animales , Protocolos de Quimioterapia Combinada Antineoplásica , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Docetaxel , Técnicas Electroquímicas , Humanos , Ratones , Modelos Biológicos , Andamios del Tejido , Ensayos Antitumor por Modelo de Xenoinjerto
8.
J Phys Ther Sci ; 27(6): 1743-5, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26180311

RESUMEN

[Purpose] The purpose of this study was to determine whether muscle activity and pressure-induced pain in the upper extremities are affected by smartphone use, and to compare the effects of phone handling with one hand and with both hands. [Subjects] The study subjects were asymptomatic women 20-22 years of age. [Methods] The subjects sat in a chair with their feet on the floor and the elbow flexed, holding a smartphone positioned on the thigh. Subsequently, the subjects typed the Korean anthem for 3 min, one-handed or with both hands. Each subject repeated the task three times, with a 5-min rest period between tasks to minimize fatigue. Electromyography (EMG) was used to record the muscle activity of the upper trapezius (UT), extensor pollicis longus (EPL), and abductor pollicis (AP) during phone operation. We also used a dolorimeter to measure the pressure-induced pain threshold in the UT. [Results] We observed higher muscle activity in the UT, AP, and EPL in one-handed smartphone use than in its two-handed use. The pressure-induced pain threshold of the UT was lower after use of the smartphone, especially after one-handed use. [Conclusion] Our results show that smartphone operation with one hand caused greater UT pain and induced increased upper extremity muscle activity.

9.
Front Immunol ; 15: 1378277, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38596687

RESUMEN

Despite significant progress in targeted therapy for acute myeloid leukemia (AML), clinical outcomes are disappointing for elderly patients, patients with less fit disease characteristics, and patients with adverse disease risk characteristics. Over the past 10 years, adaptive T-cell immunotherapy has been recognized as a strategy for treating various malignant tumors. However, it has faced significant challenges in AML, primarily because myeloid blasts do not contain unique surface antigens. The preferentially expressed antigen in melanoma (PRAME), a cancer-testis antigen, is abnormally expressed in AML and does not exist in normal hematopoietic cells. Accumulating evidence has demonstrated that PRAME is a useful target for treating AML. This paper reviews the structure and function of PRAME, its effects on normal cells and AML blasts, its implications in prognosis and follow-up, and its use in antigen-specific immunotherapy for AML.


Asunto(s)
Antígenos de Neoplasias , Leucemia Mieloide Aguda , Masculino , Humanos , Anciano , Leucemia Mieloide Aguda/terapia , Linfocitos T , Pronóstico , Leucocitos
10.
Int J Biol Macromol ; 271(Pt 1): 132610, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38788876

RESUMEN

The flammability of bio-derived poly(L-lactic acid) (PLA) greatly limits its application and eco-friendly multifunctional fire-fighting PLA-based composites are highly desired. In this work, a fully bio-based modified CS (C-CS) and commercially available eco-friendly ammonium polyphosphate (APP) were used as a synergistic flame retardant agent (C-CS/APP) to investigate its effects on fire-proofing performance and diverse properties of the PLA. The PLA/5%C-CS/5%APP composite exhibited excellent fire-resistant performance with anti-droplet, smoke-suppression and self-extinguishing property, and its limited oxygen index enhanced by 37 % (compared with neat PLA). This composite reached the highest V-0 fire safety rating, and its peak of heat release rate and total smoke production reduced by 26.5 % and 68.3 %, respectively. In addition, the char residue yield after the cone calorimeter test increased by 46 times in the composite, indicating an outstanding char-forming capacity. The condensed phase flame retardancy played a crucial role on the fire-fighting of this composite, that is, significantly enhanced char residue (as a physical barrier) blocked the heat exchange and O2 entry, and further suppressed the combustion reaction. Additionally, the PLA-based composite showed outstanding UV-absorption property, good anti-bacterial effect, and increased hydrophilicity and crystallizability.


Asunto(s)
Incendios , Retardadores de Llama , Poliésteres , Humo , Poliésteres/química , Polifosfatos/química , Polifosfatos/farmacología
11.
Front Pharmacol ; 14: 1242491, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37727390

RESUMEN

Zanubrutinib is a Bruton tyrosine kinase (BTK) inhibitor used in B cell malignancy treatment and is generally well tolerated in most patients. Zanubrutinib-induced aseptic meningitis is currently not reported. Herein, we present the first case of zanubrutinib-induced aseptic meningitis. A 33-year-old woman was diagnosed with relapsed/refractory follicular lymphoma and subsequently developed aseptic meningitis after receiving zanubrutinib treatment. We reviewed the literature and uncovered the lack of current reports on zanubrutinib or other BTK inhibitor-induced aseptic meningitis. Moreover, we summarized cases on aseptic meningitis induced by common chemotherapy and targeted drugs used for hematological diseases. Drug-induced aseptic meningitis (DIAM) is a drug-induced meningeal inflammation. The possible pathogenesis is the direct stimulation of the meninges via intrathecal injection of chemotherapy drugs and immune hypersensitivity response caused by immunosuppressive drugs. It is more common in women with immune deficiency and mainly manifests as persistent headache and fever. Cerebrospinal fluid examinations mainly demonstrate a significant increase in cells and proteins. DIAM diagnosis needs to exclude bacterial, fungal, viral, and tuberculosis infections; neoplastic meningitis; and systemic diseases involving the meninges. The prognosis of DIAM is usually favorable, and physicians should detect and stop the causative drug. In conclusion, zanubrutinib-induced aseptic meningitis is a rare but serious complication, and physicians should be promptly aware of this adverse event to avoid serious consequences.

12.
Cancer Med ; 12(23): 21111-21117, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37937729

RESUMEN

BACKGROUND: The clinical significance of protein tyrosine phosphatase nonreceptor type 11 mutation (PTPN11mut ) in acute myeloid leukemia (AML) is underestimated. METHODS: We collected the data of AML patients with mutated PTPN11 and wild-type PTPN11 (PTPN11wt ) treated at our hospital and analyzed their clinical characteristics and prognosis. RESULTS: Fifty-nine PTPN11mut and 124 PTPN11wt AML patients were included. PTPN11mut was more common in myelomonocytic and monocytic leukemia, and was more likely to co-mutate with KRAS, KMT2C, NRAS, U2AF1, NOTCH1, IKZF1, and USH2A mutations than PTPN11wt . The overall survival for AML patients with PTPN11mut was significantly shorter than that for those with PTPN11wt (p = 0.03). The negative impact of PTPN11mut on overall survival was pronounced in the "favorable" and "intermediate" groups of ELN2017 risk stratification, as well as in the wild-type NPM1 group (p = 0.01, p = 0.01, and p = 0.04). CONCLUSION: PTPN11mut is associated with distinct clinical and molecular characteristics, and adverse prognosis in AML patients.


Asunto(s)
Leucemia Mieloide Aguda , Nucleofosmina , Adulto , Humanos , Pronóstico , Leucemia Mieloide Aguda/tratamiento farmacológico , Mutación , China/epidemiología , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética
13.
Int J Biol Macromol ; 234: 123666, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36801221

RESUMEN

In this work, the ß-cyclodextrin (ß-CD) was modified by a phosphazene compound to prepare a novel amorphous derivate (ß-CDCP), which was combined with the ammonium polyphosphate (APP) as a synergistic flame retardant (FR) of the bio-based poly(L-lactic acid) (PLA). The effects of the APP/ß-CDCP on the thermal stability, combustion behavior, pyrolysis process, fire resistance performance and crystallizability of the PLA were investigated comprehensively and in depth by thermogravimetric (TG) analysis, limited oxygen index (LOI) analysis, UL-94 test, cone calorimetry measurement, TG-infrared (TG-IR), scanning electron microscopy-energy dispersive spectrometer, Raman spectroscopy, pyrolysis-gas chromatography/mass spectrometry and differential scanning calorimetry. The PLA/5%APP/10%ß-CDCP showed a highest LOI of 33.2 %, passed V-0 rating and exhibited self-extinguish phenomenon in the UL-94 test. Also, it presented a lowest peak of heat release rate, total heat release, peak of smoke production rate and total smoke release, and a highest char yield treated by cone calorimetry analysis. In addition, the 5%APP/10%ß-CDCP shortened significantly crystallization time and enhanced crystallization rate of the PLA. Gas phase and intumescent condensed phase fire proofing mechanisms are proposed to elucidate enhanced fire resistance in this system in detail.


Asunto(s)
Oxígeno , Humo , Microesferas , Calorimetría , Poliésteres
14.
Contrast Media Mol Imaging ; 2022: 5373585, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35615731

RESUMEN

The purpose of the research was to discuss the application values of deep learning algorithm-based computed tomography perfusion (CTP) imaging combined with head and neck computed tomography angiography (CTA) in the diagnosis of ultra-early acute ischemic stroke. Firstly, 88 patients with acute ischemic stroke were selected as the research objects and performed with cerebral CTP and CTA examinations. In order to improve the effect of image diagnosis, a new deconvolution network model AD-CNNnet based on deep learning was proposed and used in patient CTP image evaluation. The results showed that the peak signal-to-noise ratio (PSNR) and feature similarity (FSIM) of the AD-CNNnet method were significantly higher than those of traditional methods, while the normalized mean square error (NMSE) was significantly lower than that of traditional algorithms (P < 0.05). 80 cases were positive by CTP-CTA, including 16 cases of hyperacute ischemic stroke and 64 cases of acute ischemic stroke. The diagnostic sensitivity was 93.66%, and the specificity was 96.18%. The cerebral blood flow (CBF), cerebral blood volume (CBV), and the mean transit time (MTT) in the infarcted area were significantly greater than those in the corresponding healthy side area, and the time to peak (TTP) was significantly less than that in the corresponding healthy side area (P < 0.05). The cerebral perfusion parameters CBF, TTP, and MTT in the penumbra were significantly different from those in the infarct central area and the corresponding contralateral area, and TTP was the most sensitive (P < 0.05). To sum up, deep learning algorithm-based CTP combined with CTA could find the location of cerebral infarction lesions as early as possible to provide a reliable diagnostic result for the diagnosis of ultra-early acute ischemic stroke.


Asunto(s)
Isquemia Encefálica , Aprendizaje Profundo , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Algoritmos , Isquemia Encefálica/diagnóstico por imagen , Angiografía Cerebral/métodos , Circulación Cerebrovascular , Angiografía por Tomografía Computarizada , Diagnóstico Precoz , Imagen de Perfusión/métodos , Accidente Cerebrovascular/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos
15.
Adv Mater ; 34(17): e2108167, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35132688

RESUMEN

Chemoimmunotherapy using nanotechnology has shown great potential for cancer therapy in the clinic. However, uncontrolled transportation and synergistic responses remain challenges. Here, a self-assembled selenopeptide nanoparticle that strengthens tumor chemoimmunotherapy through the activation of natural killer (NK) cells by the oxidative metabolite of the selenopeptide is developed. With the advantages of the enzyme-induced size-reduction and the reactive-oxygen-species-driven deselenization, this selenopeptide is able to deliver therapeutics, e.g., doxorubicin (DOX), to solid tumors and further activate the NK cells in a programmed manner. Importantly, in vitro and in vivo results prove the mutual promotion between the DOX-induced chemotherapy and the selenopeptide-induced immunotherapy, which synergistically contribute to the improved antitumor efficacy. It is anticipated that the selenopeptide may provide a type of promising stimuli-responsive immune modulator for versatile biomedical applications.


Asunto(s)
Nanopartículas , Neoplasias , Línea Celular Tumoral , Doxorrubicina/farmacología , Doxorrubicina/uso terapéutico , Humanos , Inmunoterapia , Células Asesinas Naturales , Nanomedicina , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo
16.
Int J Biol Macromol ; 222(Pt A): 305-324, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36150571

RESUMEN

Poly(L-lactic acid) (PLA) is a kind of important bio-macromolecule which can be prepared via fermentation of starch of maize and sweet potato. Flammability and extremely poor crystallizability limited its wide application. In this work, a novel Schiff base derivate (CP) was synthesized and, combined with ammonium polyphosphate (APP) as a synergistic flame retardant and nucleating agent to investigate its effects on LOI, UL-94 rating, thermal stability, combustion behavior and crystallizability of PLA. With loading of 5%CP/10%APP, PLA showed a significantly enhanced LOI and passed V-0 fire-safety rating with self-extinguish effect. PLA/5%CP/10%APP presented the lowest pHRR, THR and TSR, and highest char residue yield, FPI and FRI in cone calorimetry test, indicating an excellent flame retardancy effect, enhanced fire safety and longer escaping time in the fire. A continuous, compact and thick char layer structure formed as a protective barrier in combustion process, to enhance heat-insulating and oxygen resistance property, thermal stability and smoke-suppressing capacity of PLA. Flame retardancy mechanism was proposed and discussed based on comprehensive and in-depth characterization techniques. Also, 5%CP/10%APP presented a good nucleation effect to enormously increase crystallizability and shorten crystallization time of PLA.


Asunto(s)
Compuestos de Amonio , Retardadores de Llama , Bases de Schiff , Poliésteres/química , Polifosfatos/química , Compuestos de Amonio/química
17.
Mol Ther Oncolytics ; 18: 467-475, 2020 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-32953981

RESUMEN

Human γδ T lymphocytes were reported to display anti-tumor effects against multiple cancers, including hepatocellular carcinoma (HCC). Aberrant expression of microRNAs (miRNAs) leads to a low response to immunotherapy. Thirty-five HCC tumor tissues and their adjacent healthy tissues were collected from patients with primary HCC who underwent tumor resection in the Third People's Hospital of Hainan Province, China. The purity of the resulting γδ T cells was identified by anti-γδ-T cell receptor-phycoerythrin (anti-γδ-TCR-PE) and anti-CD3-fluorescein isothiocyanate (anti-CD3-FITC) antibodies on flow cytometry. Human HCC cell lines HepG2 and PLC were cultured. We observed that ex vivo, expanded human γδ T cells were able to induce cell lysis of HCC. Furthermore, as miR-382 was observed to be downregulated in HCC tissues and cell lines, we found that overexpression of miR-382 increased the sensitivity of HCC cells to γδ T cells. We proved that mRNA of cellular FADD-like interleukin-1ß-converting enzyme-inhibitory protein (c-FLIP) was the target of miR-382. Inhibition of c-FLIP by miR-382 significantly promotes the cell lysis of HCC through strengthening the activation caspase 8 induced by γδ T cell treatment. In conclusion, overexpression of miR-382 promotes HCC cell lysis induced by γδ T cells through inhibiting the expression of c-FLIP.

18.
Int J Biol Macromol ; 165(Pt A): 1562-1573, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-33058980

RESUMEN

Naturally occurring thymine (TM) was incorporated into bacterial poly(3-hydroxybutyrate) (PHB) polyester to fabricate a novel and green biocomposite. Both 0.5% and 1% TM exhibit supernucleation effect on PHB, and crystallization kinetics suggests TM significantly increased Tc and Xc, and substantially shortened t1/2 of PHB. Epitaxial nucleation caused by a perfect crystal lattice matching between PHB and TM, was proposed to elucidate nucleation mechanism of PHB. Hydrogen bond interaction exists between CO, C-O-C groups of PHB and -CH3 (or -CH)/-NH- group of TM. TM interacted with CO group of PHB crystalline phase rather than that of amorphous one. In addition, two new IR crystalline bands assigned to C-O-C group of PHB appeared in the presence of TM, which arises from shift of two amorphous ones, respectively. TM enhanced onset thermal degradation temperature of PHB, mainly attributed to increased degree of crystallinity of PHB and flame retardance effect of TM.


Asunto(s)
Ácido 3-Hidroxibutírico/química , Materiales Biocompatibles/química , Hidroxibutiratos/química , Poliésteres/química , Ácido 3-Hidroxibutírico/biosíntesis , Bacterias/química , Bacterias/genética , Enlace de Hidrógeno , Cinética , Polímeros/química , Timina/química
19.
Materials (Basel) ; 12(24)2019 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-31817279

RESUMEN

The intumescent flame retardant ethylene-propylene-diene rubber (EPDM) was prepared using intumescent flame retardant (IFR), including ammonium polyphosphate (APP) /pentaerythrotol (PER) and expandable graphite (EG), as the flame retardant agent. The effects of IFR and EG on the flame retardancy, fire behavior, and thermal stability of the EPDM were investigated. The results show that IFR and EG have excellent synergistic flame retardant effects. When the mass ratio of IFR to EG is 3:1 and the total addition content is 40 phr, the limiting oxygen index (LOI) value of the EPDM material (EPDM/IFR/EG) can reach 30.4%, and it can pass a V-0 rating in the vertical combustion (UL-94) test. Meanwhile, during the cone calorimetry test, the heat release rate and total heat release of EPDM/IFR/EG are 69.0% and 33.3% lower than that of the pure EPDM, respectively, and the smoke release of the material also decreases significantly, suggesting that the sample shows good fire safety. In addition, the flame retardant mechanism of IFR and EG is systematically investigated by thermogravimetric analysis/infrared spectrometry (TG-IR), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), and the results indicate that IFR and EG have only physical interaction. Moreover, the reason why IFR exhibits a poor flame retardant effect in EPDM materials is explained.

20.
Polymers (Basel) ; 11(7)2019 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-31269645

RESUMEN

The present work focuses on the preparation of poly(l-lactide)-magnesium oxide whiskers (PLLA-MgO) composites by the in-situ polymerization method for bone repair and implant. PLLA-MgO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and solid-state 13C and 1H nuclear magnetic resonance spectroscopy (NMR). It was found that the whiskers were uniformly dispersed in the PLLA matrix through the interfacial interaction bonding between PLLA and MgO; thereby, the MgO whisker was found to be well-distributed in the PLLA matrix, and biocomposites with excellent interface bonding were produced. Notably, the MgO whisker has an effect on the crystallization behavior and mechanical properties; moreover, the in vivo degradation of PLLA-MgO composites could also be adjusted by MgO. These results show that the whisker content of 0.5 wt % and 1.0 wt % exhibited a prominent nucleation effect for the PLLA matrix, and specifically 1.0 wt % MgO was found to benefit the enhanced mechanical properties greatly. In addition, the improvement of the degrading process of the composite illustrated that the MgO whisker can effectively regulate the degradation of the PLLA matrix as well as raise its bioactivity. Hence, these results demonstrated the promising application of PLLA-MgO composite to serve as a biomedical material for bone-related repair.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA