Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
1.
J Environ Manage ; 362: 121342, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38830282

RESUMEN

In this study, Ag/Bi2O3/Bi5O7I with s-scheme heterostructures were successfully synthesized in situ by nano-silver modification of CUA-17 and halogenated hydrolysis.The growth rate of Bi2O3 crystals was effectively controlled by adjusting the doping amount of Ag, resulting in the formation of a facet-coupling heterojunctions. Through the investigation of the microstructure and compositional of catalysts, it has been confirmed that an intimate facet coupling between the Bi2O3 (120) facet and the Bi5O7I (312) facet, which provides robust support for charge transfer. Under visible light irradiation, the AgBOI.3 heterojunction photocatalyst exhibited an outstanding degradation rate of 98.2% for Bisphenol A (BPA) with excellent stability. Further characterization using optical, electrochemical, impedance spectroscopy, and electron spin resonance techniques revealed significantly enhanced efficiency in photogenerated charge separation and transfer, and confirming the s-scheme structure of the photocatalyst. Density functional theory calculations was employed to elucidate the mechanism of BPA degradation and the degradation pathway of BPA was investigated by LC-MS. Finally, the toxicity of the degradation intermediates was evaluated using T.E.S.T software.


Asunto(s)
Compuestos de Bencidrilo , Bismuto , Fenoles , Plata , Fenoles/química , Compuestos de Bencidrilo/química , Bismuto/química , Catálisis , Plata/química
2.
Neuroimage ; 264: 119700, 2022 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-36270621

RESUMEN

White matter (WM) of the fetal brain undergoes rapid development to form early structural connections. Diffusion magnetic resonance imaging (dMRI) has shown to be a useful tool to depict fetal brain WM in utero, and many studies have observed increasing fractional anisotropy and decreasing diffusivity in the fetal brain during the second-to-third trimester, whereas others reported non-monotonic changes. Unbiased dMRI atlases of the fetal brain are important for characterizing the developmental trajectories of WM and providing normative references for in utero diagnosis of prenatal abnormalities. To date, the sole fetal brain dMRI atlas was collected from a Caucasian/mixed population and was constructed based on the diffusion tensor model with limited spatial resolution. In this work, we proposed a fiber orientation distribution (FOD) based pipeline for generating fetal brain dMRI atlases, which showed better registration accuracy than a diffusion tensor based pipeline. Based on the FOD-based pipeline, we constructed the first Chinese fetal brain dMRI atlas using 89 dMRI scans of normal fetuses at gestational age between 24 and 38 weeks. Complex non-monotonic trends of tensor- and FOD-derived microstructural parameters in eight WM tracts were observed, which jointly pointed to different phases of microstructural development. Specifically, we speculated that the turning point of the diffusivity trajectory may correspond to the starting point of pre-myelination, based on which, the developmental order of WM tracts can be mapped and the order was in agreement with the order of myelination from histological studies. The normative atlas also provided a reference for the detection of abnormal WM development, such as that in congenital heart disease. Therefore, the established high-order fetal brain dMRI atlas depicted the spatiotemporal pattern of early WM development, and findings may help decipher the distinct microstructural events in utero.


Asunto(s)
Sustancia Blanca , Femenino , Humanos , Embarazo , Lactante , Sustancia Blanca/diagnóstico por imagen , Imagen de Difusión Tensora/métodos , Encéfalo/patología , Imagen de Difusión por Resonancia Magnética/métodos , Fibras Nerviosas Mielínicas
3.
J Magn Reson Imaging ; 55(1): 255-264, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34155718

RESUMEN

BACKGROUND: Prenatal diagnosis of placenta accreta spectrum (PAS) disorders is difficult. Magnetic resonance imaging (MRI) has been shown to be a useful supplementary method to ultrasound. PURPOSE: To investigate diffusion MRI (dMRI) based tractography as a tool for detecting PAS disorders, and to evaluate its performance compared with anatomical MRI. STUDY TYPE: Prospective. POPULATION: Forty-seven pregnant women in the third trimester with risk factors for PAS. FIELD STRENGTH/SEQUENCE: Using fast imaging employing steady-state acquisition and high-angular resolution dMRI at 1.5 Tesla. ASSESSMENT: Diagnosis of PAS was performed by three radiologists based on the dMRI-based feature of myometrial fiber discontinuity and on commonly used anatomical features including presence of dark band, discontinuous myometrium and bladder wall interruption. We evaluated the sensitivity, specificity, accuracy, and area-under-the-curve (AUC) of the individual features and established an integrated model with random forest analysis. STATISTICAL TESTS: Maternal age and gestational age at scan were compared between PAS and control group using a t-test, and childbearing history was compared using a chi-squared test. The random forest model was employed to combine the anatomical and dMRI features with 5-fold cross-validation, and the weight of each feature was normalized to evaluate its importance in predicting PAS. RESULTS: Based on surgical pathology reports, 16 out of 47 patients had confirmed PAS. The anatomical feature of dark bands and tractography marker achieved the highest AUC of 0.842 for predicting PAS, and the integrated anatomical and tractography features further improved the AUC of 0.880 with an accuracy of 87.2%. The tractography feature contributed most (30.1%) to the integrated model. DATA CONCLUSION: Myometrial tractography demonstrated superior performance in detecting PAS. Moreover, the combination of dMRI-based tractography and anatomical MRI could potentially improve the diagnosis of PAS disorders in clinical practice. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2.


Asunto(s)
Placenta Accreta , Imagen de Difusión por Resonancia Magnética , Femenino , Humanos , Imagen por Resonancia Magnética , Miometrio , Placenta Accreta/diagnóstico por imagen , Embarazo , Estudios Prospectivos
4.
Magn Reson Med ; 85(1): 404-412, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-32720386

RESUMEN

PURPOSE: Intravoxel incoherent motion (IVIM) imaging is widely used to evaluate microcirculatory flow, which consists of diffusive and ballistic flow components. We proposed a joint use of flow-compensated (FC) and non-compensated (NC) diffusion gradients to probe the fraction and velocity of ballistic flow in the placenta. METHODS: Forty pregnant women were included in this study and scanned on a 1.5T clinical scanner. FC and NC diffusion MRI (dMRI) sequences were achieved using a pair of identical or mirrored bipolar gradients. A joint FC-NC model was established to estimate the fraction (fb ) and velocity (vb ) of the ballistic flow. Conventional IVIM parameters (f, D, and D*) were obtained from the FC and NC data, separately. The vb and f·D*, as placental flow velocity measurements, were correlated with the umbilical-artery Doppler ultrasound indices and gestational ages. RESULTS: The ballistic flow component can be observed from the difference between the FC and NC dMRI signal decay curves. vb fitted from the FC-NC model showed strong correlations with umbilical-artery impedance indices, the systolic-to-diastolic (SD) ratio and pulsatility index (PI), with correlation coefficients of 0.65 and 0.62. The f·D* estimated from the NC data positively correlated with SD and PI, while the FC-based f·D* values showed weak negative correlations. Significant gestational-age dependence was also found in the flow velocity measurements. CONCLUSION: Our results demonstrated the feasibility of using FC and NC dMRI to noninvasively measure ballistic flow velocity in the placenta, which may be used as a new marker to evaluate placenta microcirculation.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Placenta , Difusión , Femenino , Humanos , Microcirculación , Movimiento (Física) , Placenta/diagnóstico por imagen , Embarazo
5.
Audiol Neurootol ; 23(2): 116-121, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30205364

RESUMEN

Firecrackers are still popular among the general public of various populations worldwide. This study investigated inner ear damage in patients with firecracker trauma and analyzed noise levels in 6 kinds of commercially available firecrackers. During the past 20 years, we have experienced 30 patients with firecracker trauma. An inner ear test battery comprising audiometry, cervical and ocular vestibular-evoked myogenic potential (cVEMP and oVEMP) tests and a caloric test was performed. The real-time noise levels were measured outdoors at a distance of 2, 4 and 6 m away from a lighting firecracker to mimic a noise event. Mean hearing levels at high frequencies (4,000 and 8,000 Hz) were significantly higher than those at the low and middle frequencies, indicating that firecrackers mostly cause high-tone hearing loss. For the vestibular damage, abnormality percentages were higher in the results of cVEMP (80%) and oVEMP (60%) tests, but not in the caloric test (8%). In conclusion, most firecrackers exhibited noise levels > 110 dB SPL even at a distance of 6 m. This blast injury simultaneously damaged the cochlea, saccule and utricle, but spared the semicircular canals, indicating that blast exposure potentiates the adverse effect of noise exposure on both cochlear and vestibular partitions.


Asunto(s)
Traumatismos por Explosión/complicaciones , Oído Interno/lesiones , Pérdida Auditiva Provocada por Ruido/etiología , Adulto , Audiometría/métodos , Traumatismos por Explosión/fisiopatología , Pruebas Calóricas , Oído Interno/fisiopatología , Femenino , Pérdida Auditiva Provocada por Ruido/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Potenciales Vestibulares Miogénicos Evocados/fisiología , Adulto Joven
6.
Oncogenesis ; 13(1): 36, 2024 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-39353912

RESUMEN

Immunotherapy has revolutionized cancer treatment, but the lack of a reliable predictive biomarker for treatment response remains a challenge. Alpha-1,6-Mannosylglycoprotein 6-ß-N-Acetylglucosaminyltransferase 5 (MGAT5) is a key regulator of complex N-glycan synthesis, and its dysregulation is associated with cancer progression. The lectin Phaseolus vulgaris leukoagglutinin (PHA-L) specifically binds to mature MGAT5 products. Previous studies have indicated elevated PHA-L staining in head and neck squamous cell carcinoma (HNSCC), which implies increased activity of MGAT5. However, the specific role of MGAT5 in HNSCC remains unclear. In this study, we found significantly higher PHA-L staining and MGAT5 expression in HNSCC tumors compared to adjacent non-tumor tissues. Using a mass spectrometry (MS)-based glycoproteomic approach, we identified 163 potential protein substrates of MGAT5. Functional analysis revealed that protein substrates of MGAT5 regulated pathways related to T cell proliferation and activation. We further discovered that PD-L1 was among the protein substrates of MGAT5, and the expression of MGAT5 protected tumor cells from cytotoxic T lymphocyte (CTL) killing. Treatment of nivolumab alleviated the protective effects of MGAT5 on CTL activity. Consistently, patients with MGAT5-positive tumors showed improved responses to immunotherapy compared to those with MGAT5-negative tumors. Using purified PD-L1 from HNSCC cells and a glycoproteomic approach, we further deciphered that the N35 and N200 sites carry the majority of complex N-glycans on PD-L1. Our findings highlight the critical role of MGAT5-mediated branched N-glycans on PD-L1 in modulating the interaction with the immune checkpoint receptor PD-1. Consequently, we propose that MGAT5 could serve as a biomarker to predict patients' responses to anti-PD-1 therapy. Furthermore, targeting the branched N-glycans at N35 and N200 of PD-L1 may lead to the development of novel diagnostic and therapeutic approaches.

7.
Head Neck ; 45(4): 1045-1059, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36810813

RESUMEN

BACKGROUND: Oral cancer causes significant morbidity and mortality. Chemoprevention utilizes medication or natural compounds to reverse oral premalignant lesions and to prevent second primary tumors. METHODS: A comprehensive PubMed database and Cochrane Library search from 1980 to 2021 was performed using the keywords "leukoplakia," "oral premalignant lesion," and "chemoprevention." RESULTS: Chemopreventive agents included retinoids, carotenoids, cyclooxygenase inhibitor, herbal extracts, bleomycin, tyrosine kinase inhibitors, metformin, and immune checkpoint inhibitors. Although some agents demonstrated effect in reducing premalignant lesions and preventing second primary tumors, the results among different studies were highly variable. CONCLUSIONS: The results of different trials, albeit inconsistent, provided substantial information for future studies. In the era of personalized medicine, future studies will focus on identifying specific biomarkers and molecular profile to monitor and to prevent malignant transformation. Larger trials are warranted to validate the effect of chemopreventive agents.


Asunto(s)
Neoplasias de la Boca , Neoplasias Primarias Secundarias , Lesiones Precancerosas , Humanos , Neoplasias de la Boca/prevención & control , Neoplasias de la Boca/tratamiento farmacológico , Retinoides/uso terapéutico , Quimioprevención , Carotenoides , Lesiones Precancerosas/tratamiento farmacológico , Lesiones Precancerosas/prevención & control , Leucoplasia Bucal
8.
Head Neck ; 45(3): 638-646, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36513597

RESUMEN

BACKGROUND: Radiation-induced sarcoma of the head and neck (RISHN) is a rare yet devastating potential complication of radiotherapy treatment. We aimed to evaluate the clinicopathological characteristics and molecular signatures of RISHN in patients who underwent radiotherapy for head and neck cancer (HNC) to identify high-risk patients and enable earlier cancer detection. METHODS: This study retrospectively evaluated 24 sarcoma patients who received radiotherapy for HNC between 1994 and 2019. Patients were divided into two groups based on RISHN latency period. Patient demographics, initial tumor staging, risk factors, and survival between groups were analyzed, and whole-exome sequencing (WES) of selected samples was performed. RESULTS: The median age at diagnosis of RISHN was 54 years, and the male-to-female ratio was 2:1. The latency period ranged from 0.8 to 64.4 years (median 6.5 years), with a median survival of 21.5 months. Primary cancer in the oral cavity, treatment with alkylating agents, alcohol consumption, betel nut chewing, and smoking were identified as risk factors for short (<5 years) latency periods. The majority of RISHN cases occurred in the oral cavity (58.3%). WES analysis showed that tumor necrosis factor and cell cycle checkpoint pathways were differentially involved in both patient groups. CONCLUSIONS: Although case numbers were small, our cohort represents the largest case series of RISHN from a single institution to date. Clinicians must be aware of factors affecting RISHN development and latency, and risk factor identification may lead to earlier detection and prevention in the future.


Asunto(s)
Neoplasias de Cabeza y Cuello , Neoplasias Inducidas por Radiación , Sarcoma , Neoplasias de los Tejidos Blandos , Humanos , Masculino , Femenino , Estudios Retrospectivos , Neoplasias Inducidas por Radiación/genética , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/radioterapia , Neoplasias de Cabeza y Cuello/complicaciones , Estadificación de Neoplasias , Neoplasias de los Tejidos Blandos/patología
9.
Acta Otolaryngol ; 142(2): 161-167, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35225159

RESUMEN

BACKGROUND: Long-term noise exposure may damage the cochlea and endolymph resorption system, which induces episodic vertigo and/or fluctuating hearing loss in later years. OBJECTIVE: This study adopted clinical symptoms, inner ear test battery, and/or magnetic resonance (MR) imaging to evaluate development of secondary endolymphatic hydrops (EH) in patients with noise-induced hearing loss (NIHL). METHODS: Forty NIHL patients with secondary EH were assigned to Group A. Another 40 age-and sex-matched NIHL patients without EH were assigned to Group B. All patients underwent an inner ear test battery. MR imaging was performed when diagnosis of EH was equivocal via above testing. RESULTS: Group A had significantly higher mean hearing levels (MHLs) than Group B at 1000, 2000, 4000, and 8000 Hz. Both groups displayed a significantly declining sequence of abnormality rates of the inner ear test battery. Under receiver operating characteristic (ROC) curve analysis, the cutoff threshold at 4 kHz for predicting the presence of secondary EH in NIHL patients was 52 dBHL, with a sensitivity of 62% and a specificity of 69%. CONCLUSIONS: NIHL patients revealing a typical 4 kHz dip-type audiogram with dip threshold >52 dBHL may predict development of secondary EH. A longitudinal follow-up coupled with MR imaging is required for confirmation.


Asunto(s)
Oído Interno , Hidropesía Endolinfática , Pérdida Auditiva Provocada por Ruido , Endolinfa , Hidropesía Endolinfática/complicaciones , Hidropesía Endolinfática/diagnóstico por imagen , Pérdida Auditiva Provocada por Ruido/complicaciones , Pérdida Auditiva Provocada por Ruido/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética
10.
Placenta ; 119: 17-23, 2022 03 04.
Artículo en Inglés | MEDLINE | ID: mdl-35066307

RESUMEN

INTRODUCTION: Intravoxel Incoherent Motion (IVIM) imaging has been used to assess placental microcirculatory flows. We proposed a joint analysis of flow-compensated (FC) and non-compensated (NC) diffusion MRI to estimate the fraction and velocity of ballistic microcirculatory flow (fb and vb), and evaluated the diagnostic performance of the new markers in maternal and fetal disorders. METHODS: Gestational diabetes mellitus (GDM, n = 15) pregnancies and fetal growth restriction (FGR, n = 12), along with gestational age matched normal controls (n = 19 for GDM and 15 for FGR) underwent FC and NC-encoded IVIM scans at 1.5 T. fb and vb obtained from a FC-NC joint model, along with the conventional IVIM indices, were compared between patient groups for whole-placenta and maternal/fetal sides of the placenta. A linear support vector machine (SVM) was used to classify the GDM, FGR and controls. RESULTS: vb of whole-placenta were significantly lower in both GDM (p = 0.017) and FGR (p = 0.043), compared with their controls, and the differences were more evident in the fetal side (p = 0.010 for GDM and p = 0.042 for FGR). fb and fFC showed group differences in the fetal side and DFC showed differences in whole-placenta for GDM patients. In the classification task, vb showed the highest diagnostic accuracy of 70.6% for GDM and 63.0% for FGR, and the combination of fb and vb further improved the detection accuracy to 73.5% and 66.7% for GDM and FGR, respectively. DISCUSSION: vb showed superior performance in the diagnosis of GDM and FGR, indicating the potential of the joint FC-NC IVIM method for placenta examinations.


Asunto(s)
Diabetes Gestacional/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética/métodos , Retardo del Crecimiento Fetal/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Circulación Placentaria , Estudios de Casos y Controles , Diabetes Gestacional/fisiopatología , Femenino , Retardo del Crecimiento Fetal/fisiopatología , Humanos , Microcirculación , Embarazo
11.
Mar Pollut Bull ; 151: 110819, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32056612

RESUMEN

Mussels (Perna viridis) were collected from the northern coast of the South China Sea (NSCS) to investigate the geographical distribution and potential risk of dichlorodiphenyltrichloroethane and its metabolites (DDTs). DDTs had concentrations that ranged from 248 ng/g to 4650 ng/g lipid weight (lw), with an average of 807 ± 932 ng/ng lw. A comparison of the levels of DDTs in mussels indicated that the NSCS is still one of the most polluted areas in the world, although a decreasing trend was observed. DDT metabolites were predominant in all samples, suggesting that historical residue was the main source of DDT pollution. However, there were new inputs of DDTs which likely associated with antifouling paints. The human health risk assessment revealed that the current concentrations of DDTs in mussels might pose little health risk for the consumers.


Asunto(s)
DDT/análisis , Monitoreo del Ambiente , Perna , Contaminantes Químicos del Agua/análisis , Animales , China , DDT/metabolismo , DDT/toxicidad , Humanos , Medición de Riesgo , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/toxicidad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA