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1.
Clin Case Rep ; 12(4): e8726, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38550741

RESUMO

An epidermoid cyst is a benign tumor in many locations. The symptoms of an epidermoid cyst depend on its location. The brain or spine MRI can confirm the lesion. Removing total decompression is the first choice in treatment with a symptomatic cyst.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38381311

RESUMO

Cellulose/ZnO (CZ) nanocomposites are promising antimicrobial materials known for their antibiotic-free nature, biocompatibility, and environmental friendliness. In this study, cellulose fibers extracted from lotus petioles were utilized as a substrate and decorated with various shapes of ZnO nanoparticles (NPs), including small bean, hexagonal ingot-like, long cylindrical, and hexagonal cylinder-shaped NPs. Increasing zinc salt molar concentration resulted in highly crystalline ZnO NPs forming and enhanced interactions between ZnO NPs and -OH groups of cellulose. The thermal stability and UV-visible absorption properties of the CZ samples were influenced by ZnO concentration. Notably, at a ZnO molar ratio of 0.1, the CZ 0.1 sample demonstrated the lowest weight loss, while the optical band gap gradually decreased from 3.0 to 2.45 eV from the CZ 0.01 to CZ 1.0 samples. The CZ nanocomposites exhibited remarkable antibacterial activity against both Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative) bacteria under visible light conditions, with a minimum inhibitory concentration (MIC) of 0.005 mg/mL for both bacterial strains. The bactericidal effects increased with higher concentrations of ZnO NPs, even achieving 100% inhibition. Incorporating ZnO NPs onto cellulose fibers derived from lotus plants presents a promising avenue for developing environmentally friendly materials with broad applications in antibacterial and environmental fields.

3.
PLoS One ; 18(10): e0292971, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37883345

RESUMO

This paper contributes to smart greenhouses and IoT (Internet of Things) research. Our pioneering achievement centers on successfully designing, constructing, and testing a 30m2 smart greenhouse, explicitly focusing on the cultivation and development of Brassica Juncea, a mustard variety commonly grown in Vietnam. The construction phase entailed the meticulous integration of diverse IoT technologies and systems, culminating in the creation of a finely tuned environment to meet the unique needs of Brassica Juncea cultivation. Notably, our research team has realized the physical infrastructure and developed and implemented a robust web interface. This interface empowers users to monitor and remotely control the smart greenhouse conveniently. It provides real-time visualization of critical parameters, including temperature, humidity, soil moisture, and light intensity, enabling precise monitoring and supporting informed decision-making in crop management. In addition to the web interface, we have meticulously designed and completed an Android mobile application, further enhancing accessibility and convenience. This mobile app allows users to monitor and control the smart greenhouse while on the move. It is imperative to underscore that this work marks a significant milestone as the first complete smart greenhouse IoT solution dedicated to developing Brassica Juncea. Our pioneering accomplishments not only advance the frontiers of innovative greenhouse and IoT research but also contribute substantially to the progress of intelligent agriculture.


Assuntos
Agricultura , Mostardeira , Umidade , Inteligência , Internet
4.
Sci Rep ; 13(1): 12310, 2023 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-37516760

RESUMO

Numerous ports worldwide are adopting automation to boost productivity and modernize their operations. At this point, smart ports become a more important paradigm for handling increasing cargo volumes and increasing operational efficiency. In fact, as ports become more congested and cargo volumes increase, the need for accurate navigation through seaports is more pronounced to avoid collisions and the resulting consequences. To this end, digital twin (DT) technology in the fifth-generation (5G) networks and drone-assisted data collection can be combined to provide precise ship maneuvering. In this paper, we propose a DT model using drone-assisted data collection architecture, called TwinPort, to offer a comprehensive port management system for smart seaports. We also present a recommendation engine to ensure accurate ship navigation within a smart port during the docking process. The experimental results reveal that our solution improves the trajectory performance by approaching the desired shortest path. Moreover, our solution supports significantly reducing financial costs and protecting the environment by reducing fuel consumption.

5.
Sensors (Basel) ; 23(8)2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37112238

RESUMO

In this study, we consider the combination of clustering and resource allocation based on game theory in ultra-dense networks that consist of multiple macrocells using massive multiple-input multiple-output and a vast number of randomly distributed drones serving as small-cell base stations. In particular, to mitigate the intercell interference, we propose a coalition game for clustering small cells, with the utility function being the ratio of signal to interference. Then, the optimization problem of resource allocation is divided into two subproblems: subchannel allocation and power allocation. We use the Hungarian method, which is efficient for solving binary optimization problems, to assign the subchannels to users in each cluster of small cells. Additionally, a centralized algorithm with low computational complexity and a distributed algorithm based on the Stackelberg game are provided to maximize the network energy efficiency (EE). The numerical results demonstrate that the game-based method outperforms the centralized method in terms of execution time in small cells and is better than traditional clustering in terms of EE.

6.
Sci Rep ; 13(1): 1562, 2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36709391

RESUMO

Quantum entanglement is one of the essential resources involved in quantum information processing tasks. However, its detection for usage remains a challenge. The Bell-type inequality for relative entropy of coherence serves as an entanglement witness for pure entangled states. However, it does not perform reliably for mixed entangled states. This paper constructs a classifier by employing the relationship between coherence and entanglement for supervised machine learning methods. This method encodes multiple Bell-type inequalities for the relative entropy of coherence into an artificial neural network to detect the entangled and separable states in a quantum dataset.

7.
Sensors (Basel) ; 22(18)2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36146114

RESUMO

Quantum entanglement is a unique phenomenon of quantum mechanics, which has no classical counterpart and gives quantum systems their advantage in computing, communication, sensing, and metrology. In quantum sensing and metrology, utilizing an entangled probe state enhances the achievable precision more than its classical counterpart. Noise in the probe state preparation step can cause the system to output unentangled states, which might not be resourceful. Hence, an effective method for the detection and classification of tripartite entanglement is required at that step. However, current mathematical methods cannot robustly classify multiclass entanglement in tripartite quantum systems, especially in the case of mixed states. In this paper, we explore the utility of artificial neural networks for classifying the entanglement of tripartite quantum states into fully separable, biseparable, and fully entangled states. We employed Bell's inequality for the dataset of tripartite quantum states and train the deep neural network for multiclass classification. This entanglement classification method is computationally efficient due to using a small number of measurements. At the same time, it also maintains generalization by covering a large Hilbert space of tripartite quantum states.

8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 4282-4285, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-36086303

RESUMO

Wearable technology has great potential to develop human-centric healthcare applications. It reshapes our lifestyle by providing information related to physical activities, sleep monitoring, or heartbeat rhythms. In this paper, we present an innovative model for oral healthcare, which is prevention-focused to notify individuals about cleaning teeth activity. It is based on a wrist-worn accelerometer device and has two components-first, a computationally lightweight feature extractor-secondly, a robust feed-forward neural network to recognize the cleaning teeth activity. The model performance is measured using standard performance metric F1 - score (i.e., 98%), which shows the applicability in a real-life scenario. The trained model can reside inside the smartwatch as a wrist-worn wearable. It would generate personalized notifications if s/he skipped the toothbrush activity. Furthermore, it notifies the users to change the toothbrush after three months, reducing the cognitive burden. Clinical Relevance-This work help the individuals to maintain their oral health using smartwatches as a wearable device.


Assuntos
Saúde Bucal , Dispositivos Eletrônicos Vestíveis , Humanos , Redes Neurais de Computação , Escovação Dentária , Punho
9.
PLoS Negl Trop Dis ; 16(6): e0010509, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35696432

RESUMO

BACKGROUND: Dengue fever (DF) represents a significant health burden in Vietnam, which is forecast to worsen under climate change. The development of an early-warning system for DF has been selected as a prioritised health adaptation measure to climate change in Vietnam. OBJECTIVE: This study aimed to develop an accurate DF prediction model in Vietnam using a wide range of meteorological factors as inputs to inform public health responses for outbreak prevention in the context of future climate change. METHODS: Convolutional neural network (CNN), Transformer, long short-term memory (LSTM), and attention-enhanced LSTM (LSTM-ATT) models were compared with traditional machine learning models on weather-based DF forecasting. Models were developed using lagged DF incidence and meteorological variables (measures of temperature, humidity, rainfall, evaporation, and sunshine hours) as inputs for 20 provinces throughout Vietnam. Data from 1997-2013 were used to train models, which were then evaluated using data from 2014-2016 by Root Mean Square Error (RMSE) and Mean Absolute Error (MAE). RESULTS AND DISCUSSION: LSTM-ATT displayed the highest performance, scoring average places of 1.60 for RMSE-based ranking and 1.95 for MAE-based ranking. Notably, it was able to forecast DF incidence better than LSTM in 13 or 14 out of 20 provinces for MAE or RMSE, respectively. Moreover, LSTM-ATT was able to accurately predict DF incidence and outbreak months up to 3 months ahead, though performance dropped slightly compared to short-term forecasts. To the best of our knowledge, this is the first time deep learning methods have been employed for the prediction of both long- and short-term DF incidence and outbreaks in Vietnam using unique, rich meteorological features. CONCLUSION: This study demonstrates the usefulness of deep learning models for meteorological factor-based DF forecasting. LSTM-ATT should be further explored for mitigation strategies against DF and other climate-sensitive diseases in the coming years.


Assuntos
Aprendizado Profundo , Dengue , Dengue/epidemiologia , Previsões , Humanos , Incidência , Vietnã/epidemiologia
10.
Sensors (Basel) ; 22(10)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35632140

RESUMO

Aeronautical ad hoc network (AANET) has been considered a promising candidate to complete the vision of "Internet in the sky" by supporting high-speed broadband connections on airplanes for 6G networks. However, the specific characteristics of AANET restrict the applicability of conventional topology and routing management algorithms. Here, these conventional methodologies reduce the packet delivery success of AANET with higher transfer delay. At that point, the artificial intelligence (AI)-driven solutions have been adapted to AANET to provide intelligent frameworks and architectures to cope with the high complexity. The AI-driven AANET can provide intelligent topology formation, sustainability, and routing management decisions in an automated fashion by considering its specific characteristics during the learning operations. More clearly, AI-driven AANETs support intelligent management architectures, overcoming conventional methodologies' drawbacks. Although AI-based management approaches are widely used in terrestrial networks, there is a lack of a comprehensive study that supports AI-driven solutions for AANETs. To this end, this article explores the possible utilization of primary AI methodologies on the road to AI-driven AANET. Specifically, the article addresses unsupervised, supervised, and reinforcement learning as primary AI methodologies to enable intelligent AANET topology formation, sustainability, and routing management. Here, we identify the challenges and opportunities of these primary AI methodologies during the execution of AANET management. Furthermore, we discuss the critical issue of security in AANET before providing open issues.


Assuntos
Algoritmos , Inteligência Artificial
11.
J Pain Res ; 14: 3421-3428, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34754235

RESUMO

PURPOSE: To evaluate the efficacy of fused three-dimensional T2 sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) and three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) sequences for detecting neurovascular compression (NVC) in patients presenting with trigeminal neuralgia (TN). METHODS: A prospective study was carried in 33 consecutive patients (m/f: 17/16; mean age, 56.3 ± 10.4 years) with unilateral TN confirmed NVC and consensus by two experienced radiologists on fused 3D-SPACE and 3D-TOF-MRA sequences of 3-tesla (3-T) MRI. All patients underwent microvascular decompression (MVD), using photos and video in surgery as documents compared with MRI. Both the MRI and MVD were reported for three grades (contact, compression, distortion), vessel types (artery or vein), identification of offending vessel, site (juxtapontine, cisternal, and juxtapetrous), and location (cranial, caudal, medial, lateral). Agreement between preoperative MRI visualization and surgical findings was assessed using the kappa (K) statistic. RESULTS: The k-values for the agreement were excellent for the grade of NVC (k=0.82), vessel types (k=0.78), and location of conflict (k=0.74), and good for identification of the offending vessel (0.65) and the site-affected vessel (k=0.69). CONCLUSION: The fused D3-SPACE and 3D-TOF-MRA images are highly effective tools for the evaluation and treatment planning of NVC in TN patients.

12.
Stem Cells Transl Med ; 10(9): 1266-1278, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34080789

RESUMO

Human bone marrow-derived mesenchymal stem/stromal cells (BM-MSCs) represent promising stem cell therapy for the treatment of type 2 diabetes mellitus (T2DM), but the results of autologous BM-MSC administration in T2DM patients are contradictory. The purpose of this study was to test the hypothesis that autologous BM-MSC administration in T2DM patient is safe and that the efficacy of the treatment is dependant on the quality of the autologous BM-MSC population and administration routes. T2DM patients were enrolled, randomly assigned (1:1) by a computer-based system into the intravenous and dorsal pancreatic arterial groups. The safety was assessed in all the treated patients, and the efficacy was evaluated based on the absolute changes in the hemoglobin A1c, fasting blood glucose, and C-peptide levels throughout the 12-month follow-up. Our data indicated that autologous BM-MSC administration was well tolerated in 30 T2DM patients. Short-term therapeutic effects were observed in patients with T2DM duration of <10 years and a body mass index <23, which is in line with the phenotypic analysis of the autologous BM-MSC population. T2DM duration directly altered the proliferation rate of BM-MSCs, abrogated the glycolysis and mitochondria respiration of BM-MSCs, and induced the accumulation of mitochondria DNA mutation. Our data suggest that autologous administration of BM-MSCs in the treatment of T2DM should be performed in patients with T2DM duration <10 years and no obesity. Prior to further confirming the effects of T2DM on BM-MSC biology, future work with a larger cohort focusing on patients with different T2DM history is needed to understand the mechanism underlying our observation.


Assuntos
Diabetes Mellitus Tipo 2 , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Medula Óssea , Células da Medula Óssea , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/terapia , Humanos , Transplante de Células-Tronco Mesenquimais/efeitos adversos , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/metabolismo , Obesidade/metabolismo
13.
Sensors (Basel) ; 20(6)2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32192135

RESUMO

Vu Gia-Thu Bon (VGTB) river basin is an area where flash flood and heavy flood events occur frequently, negatively impacting the local community and socio-economic development of Quang Nam Province. In recent years, structural and non-structural solutions have been implemented to mitigate damages due to floods. However, under the impact of climate change, natural disasters continue to happen unpredictably day by day. It is, therefore, necessary to develop a spatial decision support system for real-time flood warnings in the VGTB river basin, which will support in ensuring the area's socio-economic development. The main purpose of this study is to develop an online flood warning system in real-time based on Internet-of-Things (IoT) technologies, GIS, telecommunications, and modeling (Soil and Water Assessment Tool (SWAT) and Hydrologic Engineering Center's River Analysis System (HEC-RAS)) in order to support the local community in the vulnerable downstream areas in the event of heavy rainfall upstream. The structure of the designed system consists of these following components: (1) real-time hydro-meteorological monitoring network, (2) IoT communication infrastructure (Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), wireless networks), (3) database management system (bio-physical, socio-economic, hydro-meteorological, and inundation), (4) simulating and predicting model (SWAT, HEC-RAS), (5) automated simulating and predicting module, (6) flood warning module via short message service (SMS), (7) WebGIS, application for providing and managing hydro-meteorological and inundation data, and (8) users (citizens and government officers). The entire operating processes of the flood warning system (i.e., hydro-meteorological data collecting, transferring, updating, processing, running SWAT and HEC-RAS, visualizing) are automated. A complete flood warning system for the VGTB river basin has been developed as an outcome of this study, which enables the prediction of flood events 5 h in advance and with high accuracy of 80%.

14.
IEEE Access ; 8: 115655-115661, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-34192110

RESUMO

The recent outbreak of the coronavirus disease 2019 (COVID-19) has rapidly become a pandemic, which calls for prompt action in identifying suspected cases at an early stage through risk prediction. To suppress its further spread, we exploit the social relationships between mobile devices in the Social Internet of Things (SIoT) to help control its propagation by allocating the limited protective resources to the influential so-called high-degree individuals to stem the tide of precipitated spreading. By exploiting the so-called differential contact intensity and the infectious rate in susceptible-exposed-infected-removed (SEIR) epidemic model, the resultant optimization problem can be transformed into the minimum weight vertex cover (MWVC) problem of graph theory. To solve this problem in a high-dynamic random network topology, we propose an adaptive scheme by relying on the graph embedding technique during the state representation and reinforcement learning in the training phase. By relying on a pair of real-life datasets, the results demonstrate that our scheme can beneficially reduce the epidemiological reproduction rate of the infection. This technique has the potential of assisting in the early identification of COVID-19 cases.

15.
IEEE Trans Nanobioscience ; 18(1): 51-60, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30530367

RESUMO

Some of the most ambitious applications of molecular communications are expected to lie in nanomedicine and advanced manufacturing. In these domains, the molecular communication system is surrounded by a range of biochemical processes, some of which may be sensitive to chemical species used for communication. Under these conditions, the biological system and the molecular communication system impact each other. As such, the problem of coexistence arises, where both the reliability of the molecular communication system and the function of the biological system must be ensured. In this paper, we study this problem with a focus on interactions with biological systems equipped with chemosensing mechanisms, which arises in a large class of biological systems. We motivate the problem by considering chemosensing mechanisms arising in bacteria chemotaxis, a ubiquitous and well-understood class of biological systems. We, then, propose strategies for a molecular communication system to minimize the disruption of biological system equipped with a chemosensing mechanism. This is achieved by exploiting tools from the theory of chemical reaction networks. To investigate the capabilities of our strategies, we obtain fundamental information theoretic limits by establishing a new connection with the problem of covert communications.


Assuntos
Biotecnologia , Comunicação , Modelos Biológicos , Modelos Químicos , Nanotecnologia , Quimiotaxia , Transdução de Sinais
16.
Sensors (Basel) ; 18(5)2018 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-29738499

RESUMO

The fifth-generation (5G) communications systems are expecting to support users with diverse quality-of-service (QoS) requirements. Beside these requirements, the task with utmost importance is to support the emergency communication services during natural or man-made disasters. Most of the conventional base stations are not properly functional during a disaster situation, so deployment of emergency base stations such as mobile personal cell (mPC) is crucial. An mPC having moving capability can move in the disaster area to provide emergency communication services. However, mPC deployment causes severe co-channel interference to the users in its vicinity. The problem in the existing resource allocation schemes is its support for static environment, that does not fit well for mPC. So, a resource allocation scheme for mPC users is desired that can dynamically allocate resources based on users’ location and its connection establishment priority. In this paper, we propose a public safety users priority-based context-aware resource allocation (PS-CARA) scheme for users sum-rate maximization in disaster environment. Simulations results demonstrate that the proposed PS-CARA scheme can increase the user average and edge rate around 10.3% and 32.8% , respectively because of context information availability and by prioritizing the public safety users. The simulation results ensure that call blocking probability is also reduced considerably under the PS-CARA scheme.

17.
J Antimicrob Chemother ; 63(5): 1058-63, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19264791

RESUMO

OBJECTIVES: The aim of this study was to measure the impact on antibiotic use of a computer-generated alert prompting post-prescription review and direct counselling in hospital wards. METHODS: A computer-generated alert on new prescriptions of 15 antibiotics was reviewed weekly by an infectious disease physician for 41 weeks. During the first 6 months of the study, criteria selected for potential intervention were: (i) a planned duration of treatment of > or =10 days; (ii) discordance between the spectrum of the prescribed antibiotic and available microbiological results; or (iii) prescriptions of broad-spectrum beta-lactams, fluoroquinolones, glycopeptides or linezolid. During the following 5 months, the alert was restricted to any prescription of the 15 antibiotics in the 9 wards where overall antibiotic use had not decreased in the past year. RESULTS: We analysed 2385 prescriptions, 932 (39%) of which generated an alert for potential intervention. Among the latter, 482 (51.7%) prescriptions prompted direct counselling, mainly for shortening the planned duration of therapy (18.9%), withdrawing antibiotics (16.2%) or streamlining therapy (15.5%). The attending physicians' compliance with the recommendations was 80%. The overall median (interquartile range) days of therapy prescribed by the attending physicians was reduced from an initial duration of 8 (7-14) to 7 (6-11) days (P < 0.0001), resulting in 26.5% less antibiotic days prescribed. The time required for the intervention was 6 h per week. CONCLUSIONS: This computer-prompted post-prescription review led physicians to modify one half of the antibiotic courses initially prescribed and was well accepted by the majority, although they had not requested counselling.


Assuntos
Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Revisão de Uso de Medicamentos/métodos , Prescrição Eletrônica , Sistemas Computacionais , Aconselhamento , Fidelidade a Diretrizes , Hospitais , Humanos
18.
Anal Biochem ; 319(2): 304-13, 2003 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-12871726

RESUMO

We have created a stable, tetracycline-inducible HeLa cell line that overexpresses murine uridine diphosphate-N-acetylglucosaminyl transferase (OGT). Tetracycline increased cytosolic OGT activity about 4-fold in a dose-dependent manner (ED(50)=0.03 microg/ml) with enhanced activity observable at 8h and maximal activity observable by 40h. Enhanced OGT activity was due to overexpression of OGT protein as determined by Western analysis. Trichostatin A (TSA), a potent and specific histone deacetylase inhibitor (HDI), markedly enhanced tetracycline-induced OGT gene expression, resulting in a >10-fold increase in OGT activity (>50-fold compared to that of uninduced cells). Other HDIs such as butyrate (ED(50)=1.6mM) and propionate (ED(50)=8mM) were similarly effective, but less potent than TSA (ED(50)=120 nM). We next examined the appearance of recombinant OGT in cytosol and nucleosol at various times (10 min to 6h) after inducing OGT gene. Within 2h, recombinant OGT was detected by Western analysis in both cytosol and nucleosol. This indicates rapid biosynthesis and accumulation of recombinant OGT in the cytosol and subsequent nuclear translocation. Entry of OGT into the nucleus was closely correlated with enhanced O-linked glycosylation of nuclear proteins, indicating that recombinant OGT was enzymatically active. The ability to rapidly induce OGT expression in a stable cell line provides an excellent model system to study the mechanism(s) underlying OGT nuclear translocation and a useful system to elucidate the cascade of signaling events related to O-linked glycosylation.


Assuntos
Inibidores Enzimáticos/farmacologia , Inibidores de Histona Desacetilases , Tetraciclina/farmacologia , Uridina Difosfato N-Acetilglicosamina/biossíntese , Animais , Transporte Biológico , Butiratos/farmacologia , Núcleo Celular/enzimologia , Citosol/enzimologia , Relação Dose-Resposta a Droga , Indução Enzimática/efeitos dos fármacos , Ácidos Graxos/química , Ácidos Graxos/farmacologia , Galactose/análogos & derivados , Expressão Gênica , Glicoproteínas/química , Glicoproteínas/metabolismo , Células HeLa , Humanos , Ácidos Hidroxâmicos/farmacologia , Cinética , Camundongos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Uridina Difosfato N-Acetilglicosamina/genética , Uridina Difosfato N-Acetilglicosamina/metabolismo
19.
Anal Biochem ; 314(2): 169-79, 2003 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-12654302

RESUMO

UDP-N-acetylglucosaminyl transferase (OGT) catalyzes O-linked glycosylation of cytosolic and nuclear proteins, but enzyme studies have been hampered by the lack of a rapid, sensitive, and economical OGT assay. Employed assay methods typically involved the use of HPLC, formic acid, and large amounts of expensive radiolabeled [3H]UDP-N-acetylglucosaminyl ([3H]UDP-GlcNAc). In the current study, we have developed an OGT assay that circumvents many of these problems through four critical assay improvements: (1) identification of an abundant and enriched source of OGT enzyme (rat brain tissue), (2) utilization of a rapid method for efficiently removing salts and sugar nucleotides from cytosol (polyethylene glycol precipitation of active enzyme), (3) expression of a recombinant p62 acceptor substrate designed to facilitate purification (polyhistidine metal-chelation site), and (4) development of two alternative methods to rapidly separate free [3H]UDP-GlcNAc from 3H-p62ST acceptor peptide (trichloroacetic acid precipitation and metal-chelation affinity purification). To study the enzymology of OGT, independent of potential regulatory proteins within cytosol, we also developed and characterized an alternate OGT assay that uses antibody-purified OGT as the enzyme source. The major advantage of this assay lies in the ability to measure OGT in the absence of other cytosolic proteins.


Assuntos
Encéfalo/enzimologia , Glucosamina/análogos & derivados , N-Acetilglucosaminiltransferases/metabolismo , Animais , Anticorpos/imunologia , Anticorpos/farmacologia , Western Blotting , Precipitação Química , Citosol/efeitos dos fármacos , Citosol/enzimologia , Eletroforese em Gel de Poliacrilamida , Glucosamina/farmacologia , Masculino , N-Acetilglucosaminiltransferases/efeitos dos fármacos , N-Acetilglucosaminiltransferases/imunologia , Polietilenoglicóis/química , Cloreto de Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Cloreto de Sódio/farmacologia , Temperatura , Fatores de Tempo , Difosfato de Uridina/farmacologia
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