Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
J Magn Reson Imaging ; 57(1): 227-235, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-35652509

RESUMEN

BACKGROUND: Differential diagnosis of brain metastases subtype and primary central nervous system lymphoma (PCNSL) is necessary for treatment decisions. The application of machine learning facilitates the classification of brain tumors, but prior investigations into primary lymphoma and brain metastases subtype classification have been limited. PURPOSE: To develop a machine-learning model to classify PCNSL, brain metastases with primary lung and non-lung origin. STUDY TYPE: Retrospective. POPULATION: A total of 211 subjects with pathologically confirmed PCNSL or brain metastases (training cohort 168 and testing cohort 43). FIELD STRENGTH/SEQUENCE: A 3.0 T axial contrast-enhanced T1-weighted spin-echo inversion recovery sequence (T1WI-CE), axial T2-weighted fluid-attenuation inversion recovery sequence (T2FLAIR) ASSESSMENT: Several machine-learning models (support vector machine, random forest, and K-nearest neighbors) were built with least absolute shrinkage and selection operator (LASSO) using features from T1WI-CE, T2FLAIR, and clinical. The model with the highest performance in the training cohort was selected to differentiate lesions in the testing cohort. Then, three radiologists conducted a two-round classification (with and without model reference) using images and clinical information from testing cohorts. STATISTICAL TESTS: Five-fold cross-validation was used for model evaluation and calibration. Model performance was assessed based on sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC). RESULTS: Twenty-five image features were selected by LASSO analysis. Random forest classifier was selected for its highest performance on the training set with an AUC of 0.73. After calibration, this model achieved an accuracy of 0.70 on the testing set. Accuracies of all three radiologists improved under model reference (0.49 vs. 0.70, 0.60 vs. 0.77, 0.58 vs. 0.72, respectively). DATA CONCLUSION: The random forest model based on conventional MRI and clinical data can diagnose PCNSL and brain metastases subtypes (lung and non-lung origin). Model classification can help foster the diagnostic accuracy of specialists and streamline prognostication workflow. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 2.


Asunto(s)
Neoplasias Encefálicas , Linfoma , Humanos , Estudios Retrospectivos , Neoplasias Encefálicas/patología , Imagen por Resonancia Magnética/métodos , Linfoma/diagnóstico por imagen , Linfoma/patología , Sistema Nervioso Central/patología
2.
Cerebellum ; 21(3): 358-367, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34264505

RESUMEN

Spinocerebellar ataxias (SCAs) are a large group of hereditary neurodegenerative diseases characterized by ataxia and dysarthria. Due to high clinical and genetic heterogeneity, many SCA families are undiagnosed. Herein, using linkage analysis, WES, and RP-PCR, we identified the largest SCA36 pedigree in Asia. This pedigree showed some distinct clinical characteristics. Cognitive impairment and gaze palsy are common and severe in SCA36 patients, especially long-course patients. Although no patients complained of hearing loss, most of them presented with hearing impairment in objective auxiliary examination. Voxel-based morphometry (VBM) demonstrated a reduction of volumes in cerebellum, brainstem, and thalamus (corrected P < 0.05). Reduced volumes in cerebellum were also found in presymptomatic carriers. Resting-state functional MRI (R-fMRI) found reduced ReHo values in left cerebellar posterior lobule (corrected P < 0.05). Diffusion tensor imaging (DTI) demonstrated a reduction of FA values in cerebellum, midbrain, superior and inferior cerebellar peduncle (corrected P < 0.05). MRS found reduced NAA/Cr values in cerebellar vermis and hemisphere (corrected P < 0.05). Our findings could provide new insights into management of SCA36 patients. Detailed auxiliary examination are recommended to assess hearing or peripheral nerve impairment, and we should pay more attention to eye movement and cognitive changes in patients. Furthermore, for the first time, our multimodel neuroimaging evaluation generate a full perspective of brain function and structure in SCA36 patients.


Asunto(s)
Imagen de Difusión Tensora , Ataxias Espinocerebelosas , Cerebelo , Humanos , Imagen por Resonancia Magnética , Linaje , Ataxias Espinocerebelosas/diagnóstico por imagen , Ataxias Espinocerebelosas/genética
3.
Anal Chem ; 91(6): 4039-4046, 2019 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-30793603

RESUMEN

Although it has been demonstrated that rare-earth elements (REEs) disturb and alter the catalytic activity of numerous natural enzymes, their effects on nanomaterial-based artificial enzymes (nanozymes) have been seldom explored. In this work, the influence of REEs on the peroxidase-like activity of bare gold nanoparticles (GNPs) is investigated for the first time, and a new type of Ce3+-activated peroxidase mimetic activity of GNPs is obtained. The introduced Ce3+ can be bound to the bare GNP surface rapidly through electrostatic attraction, after which it donates its electron to the bare GNP. As H2O2 is a good electron scavenger, more •OH radicals are generated on the surfaces of the bare GNPs, which can considerably enhance TMB oxidation. Due to its redox cycling ability, the activation effect of Ce3+ is proved to be more efficient in comparison to those of the other reported metal ion activators (e.g., Bi3+, Hg2+, and Pb2+). In addition, it is determined that Ce3+ should directly contact with the gold core to trigger its activation effect. When the surface states of the bare GNPs are altered, the Ce3+-stimulated effect is strongly inhibited. Furthermore, a novel colorimetric method for Ce3+ is developed, on the basis of its enhancing effect on the peroxidase mimetic activity of bare GNPs. The sensitivity of this newly developed method for Ce3+ is excellent with a limit of detection as low as 2.2 nM. This study not only provides an effective GNP-based peroxidase mimic but also contributes in realizing new applications for nanozymes.

4.
Arch Insect Biochem Physiol ; 100(1): e21511, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30417456

RESUMEN

The Silkworm Bombyx mori is an important insect in terms of economics and a model organism with a complete metamorphosis. The economic importance of silkworms is dependent on the functions of the silkgland, a specialized organ that synthesizes silk proteins. The silk gland undergoes massive degeneration during the larval to pupal stage, which involves in cell apoptosis. In this paper, high throughput sequencing was used to detect the expression of messenger RNA (mRNA), long noncoding RNA (lncRNA), and microRNA (miRNA) from silk glands of Day 3 in the fifth instar larvae (L5D3) and the spinning 36h (sp36h). We analyzed the Gene Ontology (GO) functions of target genes of the differentially expressed lncRNAs and miRNAs. We investigated the regulations of mRNA, lncRNA, and miRNA on silk gland apoptosis in L5D3 and sp36h. In total, 10,947 lncRNAs were detected in the silk gland and the index number TCONS-00021360 lncRNA may be involved in the process of apoptosis. In addition, 344 miRNAs targeted 285 mRNAs were related to the death process under GO entry. The results indicated that miRNAs play an important role in the molecular regulation of the silk gland apoptosis compared with that of lncRNAs. Finally, we screened 746 lncRNAs and 20 miRNAs that might interact with BmDredd, and drew an interaction network among them.


Asunto(s)
Estructuras Animales/metabolismo , Apoptosis/fisiología , Bombyx/fisiología , ARN/metabolismo , Animales , Regulación de la Expresión Génica/fisiología , ARN/genética
5.
Mikrochim Acta ; 186(12): 778, 2019 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-31728642

RESUMEN

Platinum nanoparticles (Pt NPs) covered with a bovine serum albumin scaffold and a particle size of 1.5 nm (BSA-PtS NPs) are shown to display enhanced multiple enzyme-mimicking activities including peroxidase, oxidase, and catalase-like activities. The peroxidase-like activity is characterized by robustness and low signal background. BSA-PtS NPs were used to design colorimetric assays for H2O2 and glucose. H2O2 latter reacts with 3,3',5,5'-tetramethylbenzidine in the presence of BSA-PtS NPs to form a blue product with an absorption maximum at 652 nm. The assay works in the 5-250 µM H2O2 concentration range. The glucose assay is based on its glucose oxidase-catalyzed oxidation to produce gluconic acid and H2O2 which then is colorimetrically quantified. Response is linear in the 10-120 µM glucose concentration range, and the detection limit is 2 µM (at S/N = 3). The method correlates well with the glucose standard method (R2 = 0.997 in the 95% confidence interval) which confirms that glucose in human serum has been successfully detected. Graphical abstractImproved enzymatic assay for hydrogen peroxide and glucose by exploiting the enzyme-mimicking properties of BSA-coated platinum nanoparticles.


Asunto(s)
Glucemia/análisis , Colorimetría/métodos , Peróxido de Hidrógeno/análisis , Nanopartículas del Metal/química , Animales , Bencidinas/química , Catálisis , Bovinos , Colorantes/química , Glucosa Oxidasa/química , Humanos , Peróxido de Hidrógeno/química , Límite de Detección , Oxidación-Reducción , Oxidorreductasas/química , Tamaño de la Partícula , Platino (Metal)/química , Albúmina Sérica Bovina/química
6.
Arch Insect Biochem Physiol ; 93(3): 160-173, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27558456

RESUMEN

The apoptosis mechanisms in mammals were investigated relatively clearly. However, little is known about how apoptosis is achieved at a molecular level in silkworm cells. We cloned a caspase homologous gene named BmDredd (where Bm is Bombyx mori and Dredd is death-related ced-3/Nedd2-like caspase) in BmN cells from the ovary of Bm and analyzed its biological information. We constructed the N-terminal, C-terminal, and overexpression vector of BmDredd, respectively. Our results showed that the transcriptional expression level of BmDredd was increased in the apoptotic BmN cells. Furthermore, overexpression of BmDredd increased the caspase-3/7 activity. Simultaneously, RNAi of BmDredd could save BmN cells from apoptosis. The immunofluorescence study showed that BmDredd located at the cytoplasm in normal cell otherwise is found at the nucleus when cells undergo apoptosis. Moreover, we quantified the transcriptional expressions of apoptosis-related genes including BmDredd, BmDaxx (where Daxx is death-domain associated protein), BmCide-b (where Cide-b is cell death inducing DFF45-like effector), BmFadd (Fadd is fas-associated via death domain), and BmCreb (where Creb is cAMP-response element binding protein) in BmN cells with dsRNA interferences to detect the molecular mechanism of apoptosis. In conclusion, BmDredd may function for promoting apoptosis and there are various regulatory interactions among these apoptosis-related genes.


Asunto(s)
Apoptosis , Bombyx/fisiología , Caspasas/genética , Proteínas de Insectos/genética , Secuencia de Aminoácidos , Animales , Bombyx/genética , Caspasas/química , Caspasas/metabolismo , Línea Celular , Clonación Molecular , ADN Complementario/genética , ADN Complementario/metabolismo , Femenino , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Masculino , Filogenia , Reacción en Cadena en Tiempo Real de la Polimerasa , Alineación de Secuencia
7.
Arch Insect Biochem Physiol ; 90(2): 59-69, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25917878

RESUMEN

Salivary gland secretion is altered in Drosophila embryos with loss of function of the sage gene. Saliva has a reduced volume and an increased electron density according to transmission electron microscopy, resulting in regions of tube dilation and constriction with intermittent tube closure. However, the precise functions of Bmsage in silkworm (Bombyx mori) are unknown, although its sequence had been deposited in SilkDB. From this, Bmsage is inferred to be a transcription factor that regulates the synthesis of silk fibroin and interacts with another silk gland-specific transcription factor, namely, silk gland factor-1. In this study, we introduced a germline mutation of Bmsage using the Cas9/sgRNA system, a genome-editing technology, resulting in deletion of Bmsage from the genome of B. mori. Of the 15 tested samples, seven displayed alterations at the target site. The mutagenesis efficiency was about 46.7% and there were no obvious off-target effects. In the screened homozygous mutants, silk glands developed poorly and the middle and posterior silk glands (MSG and PSG) were absent, which was significantly different from the wild type. The offspring of G0 mosaic silkworms had indel mutations causing 2- or 9-bp deletions at the target site, but exhibited the same abnormal silk gland structure. Mutant larvae containing different open-reading frames of Bmsage had the same silk gland phenotype. This illustrated that the mutant phenotype was due to Bmsage knockout. We conclude that Bmsage participates in embryonic development of the silk gland.


Asunto(s)
Bombyx/fisiología , Glándulas Exocrinas/embriología , Proteínas de Insectos/metabolismo , Factores de Transcripción/metabolismo , Animales , Bombyx/embriología , Bombyx/genética , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Embrión no Mamífero , Glándulas Exocrinas/fisiología , Femenino , Proteínas de Insectos/genética , Larva/genética , Larva/crecimiento & desarrollo , Mutación , Factores de Transcripción/genética
8.
Arch Insect Biochem Physiol ; 89(2): 98-110, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25735242

RESUMEN

Rab3 GTPases are known to play key a role in vesicular trafficking, and express highest in brain and endocrine tissues. In mammals, Rab3 GTPases are paralogs unlike in insect. In this study, we cloned Rab3 from the silk gland tissue of silkworm Bombyx mori, and identified it as BmRab3. Our in silico analysis indicated that BmRab3 is an isoform with a theoretical isoelectric point and molecular weight of 5.52 and 24.3 kDa, respectively. Further, BmRab3 showed the C-terminal hypervariability for GGT2 site but having two other putative guanine nucleotide exchange factor/GDP dissociation inhibitor interaction sites. Multiple alignment sequence indicated high similarities of BmRab3 with Rab3 isoforms of other species. The phylogeny tree showed BmRab3 clustered between the species of Tribolium castaneum and Aedes aegypti. Meanwhile, the expression analysis of BmRab3 showed the highest expression in middle silk glands (MSGs) than all other tissues in the third day of fifth-instar larva. Simultaneously, we showed the differential expression of BmRab3 in the early instar larva development, followed by higher expression in male than female pupae. In vivo dsRNA interference of BmRab3 reduced the expression of BmRab3 by 75% compared to the control in the MSGs in the first day. But as the worm grew to the third day, the difference of BmRab3 between knockdown and control was only about 10%. The knockdown later witnessed underdevelopment of the larvae and pharate pupae lethality in the overall development of silkworm B. mori L.


Asunto(s)
Bombyx/fisiología , Proteínas de Insectos/fisiología , Proteínas de Unión al GTP rab3/fisiología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Femenino , Técnicas de Silenciamiento del Gen , Larva/fisiología , Masculino , Datos de Secuencia Molecular , Pupa/metabolismo , Interferencia de ARN , Análisis de Secuencia de ADN
9.
Mol Biol Rep ; 41(12): 8247-54, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25200437

RESUMEN

The Bombyx mori nucleopolyhedrovirus (BmNPV) is one of the most destructive diseases in silkworm, which has caused the main damage to sericulture industry. In this study, we developed a system of RNAi to prevent the BmNPV infection using the piggyBac transposon-derived targeting short hairpin RNA (shRNA) interference. The shRNAs targeting the genes of i.e.-1, lef-1, lef-2 and lef-3 of BmNPV were designed and used to inhibit the intracellular replication or multiplication of BmNPV in Bm cells. The highest activity was presented in the shRNA targeting the i.e.-1c of BmNPV, of which the inhibition rate reached 94.5 % in vitro. Further a stable Bm cell line of piggyBac transposon-derived targeting shRNA interference against BmNPV was established, which has a highly efficacious suppression on virus proliferation. These results indicated that the recombinant shRNA expression system was a useful tool for resistance to BmNPV in vitro. The approach by recombinant shRNAs opens a door of RNAi technology as a strategy that offering technically simpler, cheaper, and quicker gene knockdown for promising research and biotechnology application on silkworm lethal diseases.


Asunto(s)
Bombyx/virología , Técnicas de Silenciamiento del Gen/métodos , Nucleopoliedrovirus/fisiología , Animales , Elementos Transponibles de ADN , Genes Virales , Nucleopoliedrovirus/genética , ARN Interferente Pequeño , Replicación Viral
10.
Mol Biol Rep ; 40(6): 4115-22, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23640098

RESUMEN

Insect molting is an important developmental process of metamorphosis, which is initiated by molting hormone. Molting includes the activation of dermal cells, epidermal cells separation, molting fluid secretion, the formation of new epidermis and old epidermis shed and other series of continuous processes. Polyphenol oxidases, dopa decarboxylase and acetyltransferase are necessary enzymes for this process. Traditionally, the dopa decarboxylase (BmDdc) was considered as an enzyme for epidermal layer's tanning and melanization. This work suggested that dopa decarboxylase is one set of the key enzymes in molting, which closely related with the regulation of ecdysone at the time of biological molting processes. The data showed that the expression peak of dopa decarboxylase in silkworm is higher during molting stage, and decreases after molting. The significant increase in the ecdysone levels of haemolymph was also observed in the artificially fed silkworm larvae with ecdysone hormone. Consistently, the dopa decarboxylase expression was significantly elevated compared to the control. BmDdc RNAi induced dopa decarboxylase expression obviously declined in the silkworm larvae, and caused the pupae appeared no pupation or incomplete pupation. BmDdc was mainly expressed and stored in the peripheral plasma area near the nucleus in BmN cells. In larval, BmDdc was mainly located in the brain and epidermis, which is consisted with its function in sclerotization and melanization. Overall, the results described that the dopa decarboxylase expression is regulated by the molting hormone, and is a necessary enzyme for the silkworm molting.


Asunto(s)
Bombyx/enzimología , Dopa-Decarboxilasa/genética , Ecdisona/farmacología , Animales , Western Blotting , Bombyx/efectos de los fármacos , Bombyx/genética , Bombyx/crecimiento & desarrollo , Dopa-Decarboxilasa/metabolismo , Ecdisona/administración & dosificación , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Larva/efectos de los fármacos , Larva/genética , Especificidad de Órganos/efectos de los fármacos , Especificidad de Órganos/genética , Transporte de Proteínas/efectos de los fármacos , ARN Bicatenario/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo
11.
Arch Insect Biochem Physiol ; 84(2): 78-89, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24038161

RESUMEN

Molting in insects is regulated by molting hormones (ecdysteroids), which are also crucial to insect growth, development, and reproduction etc. The decreased ecdysteroid in titre results from enhanced ecdysteroid inactivation reactions including the formation of 3-epiecdyson under ecdysone oxidase and 3-dehydroecdysone 3α-reductase (3DE 3α-reductase). In this paper, we cloned and characterized 3-dehydroecdysone 3α-reductase (3DE 3α-reductase) in different tissues and developing stage of the silkworm, Bombyx mori L. The B. mori 3DE 3α-reductase cDNA contains an ORF 783 bp and the deduced protein sequence containing 260 amino acid residues. Analysis showed the deduced 3DE 3α-reductase belongs to SDR family, which has the NAD(P)-binding domain. Using the Escherichia coli, a high level expression of a fusion polypeptide band of approx. 33 kDa was observed. High transcription of 3DE 3α-reductase was mainly presented in the midgut and hemolymph in the third day of fifth instar larvae in silkworm. The expression of 3DE 3α-reductase at different stages of larval showed that the activity in the early instar was high, and then reduced in late instar. This is parallel to the changes of molting hormone titer in larval. 3DE 3α-reductase is key enzyme in inactivation path of ecdysteroid. The data elucidate the regulation of 3DE 3α-reductase in ecdyteroid titer of its targeting organs and the relationship between the enzyme and metamorphosis.


Asunto(s)
3-Hidroxiesteroide Deshidrogenasas/genética , Bombyx/metabolismo , Ecdisona/metabolismo , 3-Hidroxiesteroide Deshidrogenasas/metabolismo , Secuencia de Aminoácidos , Animales , Bombyx/genética , Bombyx/crecimiento & desarrollo , Clonación Molecular , ADN Complementario/genética , Ecdisona/genética , Ecdisteroides , Escherichia coli , Regulación del Desarrollo de la Expresión Génica , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Larva/metabolismo , Datos de Secuencia Molecular , Muda
12.
Front Neurosci ; 16: 915164, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35860295

RESUMEN

Radiation-induced functional and structural brain alterations are well documented in patients with nasopharyngeal carcinoma (NPC), followed by radiotherapy (RT); however, alterations in structure-function coupling remain largely unknown. Herein, we aimed to assess radiation-induced structure-function decoupling and its importance in predicting radiation encephalopathy (RE). We included 62 patients with NPC (22 patients in the pre-RT cohort, 18 patients in the post-RT-RE+ve cohort, and 22 patients in the post-RT-RE-ve cohort). A metric of regional homogeneity (ReHo)/voxel-based morphometry (VBM) was used to detect radiation-induced structure-function decoupling, which was then used as a feature to construct a predictive model for RE. Compared with the pre-RT group, patients in the post-RT group (which included post-RT-RE+ve and post-RT-RE-ve) showed higher ReHo/VBM coupling values in the substantia nigra (SN), the putamen, and the bilateral thalamus and lower values in the brain stem, the cerebellum, the bilateral medial temporal lobes (MTLs), the bilateral insula, the right precentral and postcentral gyri, the medial prefrontal cortex (MPFC), and the left inferior parietal lobule (IPL). In the post-RT group, negative correlations were observed between maximum dosage of RT (MDRT) to the ipsilateral temporal lobe and ReHo/VBM values in the ipsilateral middle temporal gyrus (MTG). Moreover, structure-function decoupling in the bilateral superior temporal gyrus (STG), the bilateral precentral and postcentral gyri, the paracentral lobules, the right precuneus and IPL, and the right MPFC exhibited excellent predictive performance (accuracy = 88.0%) in identifying patients likely to develop RE. These findings show that ReHo/VBM may be a novel effective imaging metric that reflects the neural mechanism underlying RE in patients with NPC.

13.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 9): o2398, 2011 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-22065510

RESUMEN

In the title mol-ecule, C(25)H(30)O(4), the two cyclo-hexene rings adopt envelope conformations. The two hy-droxy groups are involved in the formation of intra-molecular O-H⋯O hydrogen bonds. In the crystal structure, weak inter-molecular C-H⋯O hydrogen bonds link mol-ecules related by translation along the axis a into chains.

14.
Front Oncol ; 11: 687127, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34322388

RESUMEN

The diagnostic efficiency of radiation encephalopathy (RE) remains heterogeneous, and prediction of RE is difficult at the pre-symptomatic stage. We aimed to analyze the whole-brain resting-state functional connectivity density (FCD) of individuals with pre-symptomatic RE using multivariate pattern analysis (MVPA) and explore its prediction efficiency. Resting data from NPC patients with nasopharyngeal carcinoma (NPC; consisting of 20 pre-symptomatic RE subjects and 26 non-RE controls) were collected in this study. We used MVPA to classify pre-symptomatic RE subjects from non-RE controls based on FCD maps. Classifier performances were evaluated by accuracy, sensitivity, specificity, and area under the characteristic operator curve. Permutation tests and leave-one-out cross-validation were applied for assessing classifier performance. MVPA was able to differentiate pre-symptomatic RE subjects from non-RE controls using global FCD as a feature, with a total accuracy of 89.13%. The temporal lobe as well as regions involved in the visual processing system, the somatosensory system, and the default mode network (DMN) revealed robust discrimination during classification. Our findings suggest a good classification efficiency of global FCD for the individual prediction of RE at a pre-symptomatic stage. Moreover, the discriminating regions may contribute to the underlying mechanisms of sensory and cognitive disturbances in RE.

15.
Biosens Bioelectron ; 177: 112977, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33434779

RESUMEN

Assays for detecting tetanus toxoid are of great significance to be applied in the research of the safety testing of tetanus vaccine. Currently, guinea pigs or mice are usually used to evaluate the toxicity in these assays. Herein, a facile and quick biomineralization process was carried out to generate tetanus human immunoglobulin G (Tet-IgG)-functionalized Au nanoclusters (Tet-IgG-AuNCs). The obtained Tet-IgG-AuNCs exhibited strong red emission with a photoluminescence quantum yield of 13%. Based on surface plasmon resonance measurements, the apparent dissociation constant of the Tet-IgG-AuNC-tetanus toxoid complexes was measured to be 2.27 × 10-8 M. A facile detection approach was developed using a fluorescent Tet-IgG-AuNC-based immunochromatography test strip. By utilizing the high-brightness fluorescent Tet-IgG-AuNCs, this immunosensor showed favorable sensitivity with a detection limit at the level of 0.03 µg/mL. Further results demonstrated that this assay can reliably detect tetanus toxoid and therefore might provide a novel method to replace animal tests for the quantification of tetanus toxicity. Moreover, the antibody-AuNC-based immunochromatography test strip platform serves as a promising candidate to develop new approaches for detecting targeted antigens and biological events of interest.


Asunto(s)
Técnicas Biosensibles , Tétanos , Animales , Cromatografía de Afinidad , Cobayas , Humanos , Inmunoensayo , Inmunoglobulina G , Ratones , Toxoide Tetánico
16.
Nat Mater ; 7(10): 790-4, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18776890

RESUMEN

One abiding surprise in fullerene science is that I(h)-symmetric buckminsterfullerene C(60) (ref. 1) (I(h)-C(60) or (#1,812)C(60), the nomenclature specified by symmetry or by Fowler's spiral algorithm) remains the sole C(60) species experimentally available. Setting it apart from the other 1,811 topological isomers (isobuckminsterfullerenes) is its exclusive conformity with the isolated-pentagon rule, which states that stable fullerenes have isolated pentagons. Although gas-phase existence of isobuckminsterfullerenes has long been suspected, synthetic efforts have yet to yield successful results. Here, we report the realization of two isobuckminsterfullerenes by means of chlorination of the respective C(2v)- and C(s)-symmetric C(60) cages. These chlorinated species, (#1,809)C(60)Cl(8)(1) and (#1,804)C(60)Cl(12)(2), were isolated in experimentally useful yields. Structural characterization by crystallography unambiguously established the unique pentagon-pentagon ring fusions. These distinct structural features are directly responsible for the regioselectivity observed in subsequent substitution of chlorines, and also render these unprecedented derivatives of C(60) isomers important for resolving the long-standing puzzle of fullerene formation by the Stone-Wales transformation scheme.

17.
ACS Sens ; 4(2): 344-352, 2019 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-30652857

RESUMEN

In this study, on the basis of the biomineralization capability of urease, a facile, one-step, and green synthetic method has been proposed for the fabrication of gold nanoclusters (AuNCs). The prepared urease-encapsulated AuNCs (U-AuNCs) exhibited strong red fluorescence emission (λem = 630 nm) with a quantum yield as high as 17%. Interestingly, at a low concentration, the U-AuNC solution was found to be a dual-emissive system with the blue emission of the dityrosine (diTyr) residues of urease and the red emission of the embedded AuNCs. Further experiments demonstrated that p-nitrophenol (PNP) can selectively suppress the 410 nm emission of the diTyr residues of U-AuNCs without affecting the red emission of the U-AuNCs. The fluorescence quenching mechanism between U-AuNCs and PNP was systematically studied, and the leading role of the inner filter effect (IFE) was identified. Additionally, based on the sulfatase-catalyzed hydrolysis of p-nitrophenyl sulfate (PNPS) to release PNP, a self-referenced ratiometric detection method for sulfatase, which plays a crucial role in sulfur cycling, degradation of sulfated glycosaminoglycans and glycolipids, and extracellular remodeling of sulfated glycosaminoglycans, was developed by using dual-emissive U-AuNCs as the signal readout, in which the diTyr residues served as the probe and the AuNCs functioned as the internal reference. This IFE-based ratiometric sensing strategy showed a good linear relationship over the range of 0.01-1 U/mL ( R2 = 0.997). The detection limit for sulfatase activity was 0.01 U/mL. The developed protocol was successfully used to detect sulfatase activity in human serum samples. The simplicity, rapidity, low cost, high credibility, good reproducibility, and excellent selectivity of the detection platform serve as an inspiration for further applications of fluorescent AuNCs in chemo/biosensing.


Asunto(s)
Pruebas de Enzimas/métodos , Oro/química , Nanopartículas del Metal/química , Sulfatasas/metabolismo , Ureasa/química , Canavalia/enzimología , Hidrólisis , Límite de Detección , Espectrometría de Fluorescencia
18.
PLoS One ; 12(1): e0169404, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28068357

RESUMEN

Silk glands (SGs) undergo massive apoptosis driven degeneration during the larval-pupal transformation. To better understand this event on molecular level, we investigated the expression of apoptosis-related genes across the developmental transition period that spans day 4 in the fifth instar Bombyx mori larvae to day 2 pupae. Increases in the expression of BmDredd (an initiator caspase homolog) closely followed the highest BmEcR expression and resembled the expression trend of BmIcE. Simultaneously, we found that BmDredd expression was significantly higher in SG compared to other tissues at 18 h post-spinning, but reduced following injection of the apoptosis inhibitor (Z-DEVD-fmk). Furthermore, BmDredd expression correlated with changes of caspase3-like activities in SG and RNAi-mediated knockdown of BmDredd delayed SG apoptosis. Moreover, caspase3-like activity was increased in SG by overexpression of BmDredd. Taken together, the results suggest that BmDredd plays a critical role in SG apoptosis.


Asunto(s)
Apoptosis/genética , Bombyx/fisiología , Caspasas/genética , Proteínas de Insectos/genética , Seda/metabolismo , Animales , Inhibidores de Caspasas/farmacología , Caspasas/metabolismo , Expresión Génica/efectos de los fármacos , Proteínas de Insectos/metabolismo , Metamorfosis Biológica
19.
Colloids Surf B Biointerfaces ; 159: 613-619, 2017 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-28858664

RESUMEN

Fullerenes with novel structures find numerous potential applications, particularly in the fields of biology and pharmaceutics. Among various fullerene derivatives, those exhibiting amphiphilic character and capable of self-assembly into vesicles are particularly interesting, being suitable for delayed drug release. Herein, we report the synthesis and self-assembly of biocompatible hollow nanovesicles with bilayer shells from amphiphilic functionalized fullerenes C60R5Cl (R=methyl ester of 4-aminobutyric/glutamic acid or phenylalanine). The thus prepared vesicles exhibit sizes of 80-135nm (depending on R) and can be used as delayed-release carriers of anti-cancer drugs such as 5-fluorouracil, cyclophosphamide, and cisplatin, with the time of 5-fluorouracil release from drug-containing vesicles exceeding that of non-encapsulated forms by a factor of three. We further reveal the effect of R on the loading amount and release rate/amount of vesicle-encapsulated drugs, demonstrating a potential pharmaceutical application of the prepared nanovesicles depending on the nature of R.


Asunto(s)
Aminoácidos/química , Antineoplásicos/química , Cloruros/química , Liberación de Fármacos , Fulerenos/química , Cisplatino/química , Ciclofosfamida/química , Sistemas de Liberación de Medicamentos/métodos , Fluorouracilo/química
20.
J Colloid Interface Sci ; 300(1): 310-3, 2006 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-16631777

RESUMEN

The critical reverse micelle concentrations of C(12)-s-C(12).2Br (s=2,3,4,5,6,8,12) in n-heptane/n-hexanol solutions, cmc(I)s, have been determined by absorption spectrum method using iodine as probe. The values of cmc(I)s are smaller than those of the critical micelle concentrations (cmc(aq)s) in aqueous solution and reach a maximum at s=4, which is similar to the variation of cmc(aq) with s. The variation of cmc(I) with s is attributed to the alteration in the spacer chain conformation, i.e. when the spacer is short enough, it may adopt stretch configuration and when the spacer is long, it tends to bend towards the continuous oil phase to achieve a more densely packing of the quaternary ammonium heads on the surface of the core.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA