Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-38581337

RESUMO

Objective: With the improvement of living standards, consumers are paying more and more attention to the quality of rice. Traditional rice quality detection relies on human sensory judgment, which is inaccurate and inefficient. With the continuous development of molecular imaging technology, more and more scholars at home and abroad have begun to pay attention to its application in the nondestructive testing of agricultural products. Molecular imaging technology combines the advantages of spectral technology and image technology, which can achieve rapid, nondestructive and accurate detection of rice quality. In this paper, taking rice as the research object, we carried out nondestructive detection research on rice varieties, moisture and starch content using molecular imaging technology. We proposed a rapid detection method based on molecular imaging technology for rice variety identification, moisture content and starch content. Molecular images of the rice samples from four origins were obtained using a molecular imaging system, the regions of interest of the rice were identified and, spectral data, textural features and morphological features of the rice were extracted. Spectral, textural and morphological features were selected by principal component analysis (PCA), and nine feature wavelengths were obtained and an optimal model was established with an accuracy of 91.67%, which demonstrated the feasibility of molecular imaging. By comparing the models, the BCC-LS-SVR model based on the RB function had the highest accuracy with R2 of 0.989, RMSEP of 0.767%, R2 of 0.985, and RMSEC of 0.591%. Moreover, starchy rice was detected using molecular imaging. The PCA-SVR model based on the RBF kernel function had the highest accuracy with R2 of 0.989, RMSEC of 0.445%, R2 of 0.991, and RMSEP of 0.669%. Our models demonstrated high accuracy in identifying rice varieties, as well as quantifying moisture and starch content, showcasing the feasibility of molecular imaging technology in rice quality assessment. This research offers a rapid, nondestructive, and accurate method for rice quality assessment, promising significant benefits for agricultural producers and consumers.

2.
Mikrochim Acta ; 191(5): 265, 2024 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-38625451

RESUMO

Sleep deprivation (SD) is highly prevalent in the modern technological world. Emerging evidence shows that sleep deprivation is associated with oxidative stress. At the organelle level, the Golgi apparatus actively participates in the stress response. In this study, to determine whether SD and Golgi apparatus stress are correlated, we rationally designed and fabricated a novel Golgi apparatus-targeted ratiometric nanoprobe called Golgi dots for O2·- detection. This probe exhibits high sensitivity and selectivity in cells and brain slices of sleep-deprived mice. Golgi dots can be readily synthesized by coprecipitation of Golgi-F127, an amphiphilic polymer F127 modified with a Golgi apparatus targeting moiety, caffeic acid (CA), the responsive unit for O2·-, and red emissive carbon nanodots (CDs), which act as the reference signal. The fluorescence emission spectrum of the developed nanoprobe showed an intense peak at 674 nm, accompanied by a shoulder peak at 485 nm. As O2·- was gradually added, the fluorescence at 485 nm continuously increased; in contrast, the emission intensity at 674 nm assigned to the CDs remained constant, resulting in the ratiometric sensing of O2·-. The present ratiometric nanoprobe showed high selectivity for O2·- monitoring due to the specific recognition of O2·- by CA. Moreover, the Golgi dots exhibited good linearity with respect to the O2·- concentration within 5 to 40 µM, and the limit of detection (LOD) was ~ 0.13 µM. Additionally, the Golgi dots showed low cytotoxicity and an ability to target the Golgi apparatus. Inspired by these excellent properties, we then applied the Golgi dots to successfully monitor exogenous and endogenous O2·- levels within the Golgi apparatus. Importantly, with the help of Golgi dots, we determined that SD substantially elevated O2·- levels in the brain.


Assuntos
Encéfalo , Ácidos Cafeicos , Polietilenos , Polipropilenos , Privação do Sono , Animais , Camundongos , Complexo de Golgi , Suplementos Nutricionais
3.
Nat Biomed Eng ; 6(6): 683-705, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35361935

RESUMO

Peripheral neurons that sense glucose relay signals of glucose availability to integrative clusters of neurons in the brain. However, the roles of such signalling pathways in the maintenance of glucose homoeostasis and their contribution to disease are unknown. Here we show that the selective activation of the nerve plexus of the hepatic portal system via peripheral focused ultrasound stimulation (pFUS) improves glucose homoeostasis in mice and rats with insulin-resistant diabetes and in swine subject to hyperinsulinemic-euglycaemic clamps. pFUS modulated the activity of sensory projections to the hypothalamus, altered the concentrations of metabolism-regulating neurotransmitters, and enhanced glucose tolerance and utilization in the three species, whereas physical transection or chemical blocking of the liver-brain nerve pathway abolished the effect of pFUS on glucose tolerance. Longitudinal multi-omic profiling of metabolic tissues from the treated animals confirmed pFUS-induced modifications of key metabolic functions in liver, pancreas, muscle, adipose, kidney and intestinal tissues. Non-invasive ultrasound activation of afferent autonomic nerves may represent a non-pharmacologic therapy for the restoration of glucose homoeostasis in type-2 diabetes and other metabolic diseases.


Assuntos
Diabetes Mellitus Experimental , Glucose , Animais , Diabetes Mellitus Experimental/terapia , Glucose/metabolismo , Homeostase , Hipotálamo/metabolismo , Fígado/metabolismo , Camundongos , Ratos , Suínos
4.
Molecules ; 26(21)2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34770902

RESUMO

Multiple insecticides' residues after the mixed application of several neonicotinoids cause combined pollution and bring new challenges to food safety and pest control during agricultural production. In this study, three neonicotinoid insecticides, namely imidacloprid (IMI), acetamiprid (ACE), and thiamethoxam (TMX), were mixed and evenly sprayed on Brassica chinensis L. in the field. Then, the insecticides' residues were dynamically monitored to determine the differences in their rates of dissipation and final residues after 10 days. The results showed that the dissipation kinetics of neonicotinoids still conformed to the first-order kinetic model for binary or ternary application of neonicotinoid mixtures, with all determination coefficients (R2) being above 0.9 and the dissipation half-life (DT50) being 2.87-6.74 d. For treatment groups with five times the recommended dosages (IMI 300 g·hm-2, ACE 900 g·hm-2, and TMX 600 g·hm-2), mixed insecticides had a slower dissipation rate, and the DT50 values of mixtures were longer than those of single insecticides. Moreover, the final insecticide residues with mixed application were higher than those of single compounds at 10 d after spraying. Thus, mixed applications of neonicotinoids may increase food safety risks as they increase the final insecticide residues in Brassica chinensis L., and care should therefore be taken when considering the combined use of such compounds.


Assuntos
Brassica/química , Neonicotinoides/química , Cromatografia Líquida de Alta Pressão , Inseticidas/química , Modelos Químicos , Especificidade de Órgãos , Compostos Fitoquímicos/química , Extratos Vegetais/química
5.
Biosci Rep ; 41(5)2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-33881140

RESUMO

Shensu IV is a Chinese prescription well-known for its function in treating chronic kidney diseases. However, the potential mechanisms underlying how Shensu IV exerts its effects remain unclear. In the present study, we investigated the effects of Shensu IV on glomerular podocyte injury in nephrotic rats and puromycin-induced injury in cultured podocytes, and assessed the associated molecular mechanisms. Liquid chromatography-mass spectrometry (LC-MS) results showed that the main components of Shensu IV were l-Carnitine, P-lysoPC (LPC) 16:0, Coumaroyl tyramine, Tetramethylpyrazine, LPC 18:1, Choline, (S,S)-Butane-2,3-diol, and Scopoletin. We further found that nephrotic rats displayed pathological alterations in kidney tissues and ultrastructural changes in glomerular podocytes; however, these effects were reversed with Shensu IV treatment. Compared with the control, the numbers of autophagosomes were markedly reduced in the model group, but not in the Shensu IV treatment group. Furthermore, the expression of p62 was significantly higher in the model group than in the controls, whereas the LC3-II/I ratio was significantly lower; however, these changes were not observed when Shensu IV was administered. The protective effects of Shensu IV were further confirmed in podocytes displaying puromycin-induced injury. Compared with control group, the expression of long non-coding RNA (lncRNA) H19, mTOR, p-mTOR, and p62 was significantly increased in the puromycin group, whereas that of distinct subgroup of the RAS family member 3 (DIRAS3) was significantly decreased, as was the LC3-II/I ratio. The opposite results were obtained for both shH19- and Shensu IV-treated cells. Collectively, our data demonstrated that Shensu IV can prevent glomerular podocyte injury in nephrotic rats and puromycin-treated podocytes, likely via promoting lncRNA H19/DIRAS3-regulated autophagy.


Assuntos
Autofagia , Medicamentos de Ervas Chinesas/uso terapêutico , Nefrose/tratamento farmacológico , Podócitos/efeitos dos fármacos , RNA Longo não Codificante/metabolismo , Proteínas rho de Ligação ao GTP/genética , Animais , Células Cultivadas , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Nefrose/etiologia , Nefrose/prevenção & controle , Podócitos/metabolismo , Puromicina/toxicidade , RNA Longo não Codificante/genética , Ratos , Ratos Sprague-Dawley , Serina-Treonina Quinases TOR/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo
6.
Sci Rep ; 11(1): 5096, 2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33658530

RESUMO

Current codes for fire protection of buildings are mainly based on the movement of adults and neglect the movement characteristic of pre-school children. Having a profound comprehension of the difference between children and adults passing bottlenecks is of great help to improve the safety levels of preschool children. This paper presents an experimental study on the bottleneck flow of pre-school children in a room. The movement characteristics of children's and adults' bottleneck flow are investigated with two macroscopic properties: density and speed profiles as well as microscopic characteristic time: motion activation time, relaxation time, exit travel time and time gap. Arch-like density distributions are observed both for highly motivated children and adults, while the distance between the peak density region and the exit location is shorter for children and longer for adults. Children's movement is less flexible manifested as longer motion activation time and longer relaxation time compared to that of adults. The findings from this study could enhance the understanding of crowd dynamics among the children population and provide supports for the scientific building design for children's facilities.


Assuntos
Aglomeração/psicologia , Incêndios , Motivação/fisiologia , Segurança , Velocidade de Caminhada/fisiologia , Adolescente , Adulto , Pré-Escolar , Feminino , Humanos , Masculino , Movimento (Física) , Relaxamento , Estudantes , Fatores de Tempo , Adulto Jovem
7.
Carbohydr Polym ; 251: 117088, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142629

RESUMO

Sea cucumbers were nutritional food and traditional Chinese medicine. In this study, fucosylated chondroitin sulfate from sea cucumber Stichopus chloronotus (fCS-Sc), a potential anticoagulant agent and immunological adjuvant, was investigated for its immune activation effects on RAW 264.7 macrophage for the first time. The results indicated that fCS-Sc could significantly promote the proliferation, the pinocytic activity of RAW 264.7 cells, and the production of NO, TNF-α, IL-1ß, and IL-6. The fluorescence labeling assay indicated that fCS-Sc could bind to the macrophage. Moreover, the specific pattern recognition receptor inhibition assays showed that toll-like receptor 4 (TLR4) and TLR2 were involved in the recognition of fCS-Sc. Western blot assays indicated that fCS-Sc could induce degradation of cytoplasm IκB-α, and promotion of NF-κB p65 subunit translocation to nucleus, leading to a functional improvement of macrophage through NF-κB pathway. The results suggested that fCS-Sc might served as a promising candidate of immunomodulator.


Assuntos
Sulfatos de Condroitina/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Stichopus/química , Animais , Proliferação de Células/efeitos dos fármacos , Sulfatos de Condroitina/isolamento & purificação , Citocinas/imunologia , Imunomodulação , Camundongos , Subunidade p50 de NF-kappa B/imunologia , Pinocitose/efeitos dos fármacos , Células RAW 264.7
8.
Food Funct ; 10(8): 5124-5139, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31364648

RESUMO

Hyperlipidemia is a major cause of atherosclerosis. Reverse cholesterol transport (RCT) is believed to attenuate hyperlipidemia and the progression of atherosclerosis. Although fucoidans are reported to have hypolipidemic effects, the underlying mechanisms are unclear. Furthermore, few reports have revealed the anti-atherosclerotic effects and the underlying mechanisms of fucoidans. This study was designed to investigate the anti-atherosclerotic effect and mechanisms of the fucoidan from seaweed A. nodosum. Our results demonstrated that the fucoidan administration ameliorated atherosclerotic lesion and lipid profiles in a dose-dependent manner in the apolipoprotein E-deficient (apoE-/-) mice fed a high-fat diet. In the apoE-/- mice liver, the fucoidan treatment significantly increased the expression of scavenger receptor B type 1 (SR-B1), peroxisome proliferator-activated receptor (PPAR) α and ß, liver X receptor (LXR) α, ATP-binding cassette transporter (ABC) A1 and ABCG8; and markedly decreased the expression of PPARγ and sterol regulatory element-binding protein (SREBP) 1c, but not low-density lipoprotein receptor, proprotein convertase subtilisin/kexin type 9, cholesterol 7 alpha-hydroxylase A1, LXRß and ABCG1. In the small intestine of the apoE-/- mice, the fucoidan treatment significantly reduced the expression of Niemann-Pick C1-like 1 (NPC1L1) and dramatically improved ABCG8 levels. These results demonstrated for the first time that the fucoidan from A. nodosum attenuated atherosclerosis by regulating RCT-related genes and proteins expression in apoE-/- mice. In summary, this fucoidan from A. nodosum may be explored as a potential compound for prevention or treatment of hyperlipidemia-induced atherosclerosis.


Assuntos
Apolipoproteínas E/genética , Ascophyllum/química , Aterosclerose/tratamento farmacológico , Extratos Vegetais/administração & dosagem , Polissacarídeos/administração & dosagem , Alga Marinha/química , Animais , Apolipoproteínas E/deficiência , Aterosclerose/etiologia , Aterosclerose/genética , Aterosclerose/metabolismo , Humanos , Hiperlipidemias/complicações , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Masculino , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de LDL/genética , Receptores de LDL/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo
9.
J Agric Food Chem ; 67(20): 5782-5791, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31055921

RESUMO

Reverse cholesterol transport (RCT) is a physiological process, in which excess peripheral cholesterol is transported to the liver and further excreted into the bile and then feces. Recently, fucoidans are reported to have a lipid-lowering effect. This study was designed to investigate whether fucoidan from the brown seaweed Ascophyllum nodosum lowers lipid by modulating RCT in C57BL/6J mice fed a high-fat diet. Our results indicated that fucoidan intervention significantly reduced plasma triglyceride, total cholesterol, and fat pad index and markedly increased high-density lipoprotein cholesterol in a dose-dependent manner. In the liver, fucoidan significantly increased the expression of peroxisome proliferator-activated receptor (PPAR)α, PPARγ, liver X receptor (LXR)ß, adenosine triphosphate (ATP) binding cassette (ABC)A1, ABCG8, low-density lipoprotein receptor (LDLR), scavenger receptor B type 1 (SR-B1), and cholesterol 7-α-hydroxylase A1 (CYP7A1) and decreased the triglyceride level and expression of proprotein convertase subtilisin/kexin type 9 (PCSK9) and PPARß but had no effect on LXRα, ABCG1, and ABCG5. In the small intestine, the fucoidan treatment significantly reduced the expression of Niemann-Pick C1-like 1 (NPC1L1) and improved ABCG5 and ABCG8. These results demonstrated that fucoidan can improve lipid transfer from plasma to the liver by activating SR-B1 and LDLR and inactivating PCSK9 and upregulate lipid metabolism by activating PPARα, LXRß, ABC transporters, and CYP7A1. In the small intestine, this fucoidan can decrease cholesterol absorption and increase cholesterol excretion by activating NPC1L1 and ABCG5 and ABCG8, respectively. In conclusion, fucoidan from A. nodosum may lower lipids by modulating RCT-related protein expression and can be explored as a potential compound for prevention or treatment of hyperlipidemia-related diseases.


Assuntos
Ascophyllum/química , Colesterol/metabolismo , Hiperlipidemias/tratamento farmacológico , Hipolipemiantes/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Polissacarídeos/administração & dosagem , Alga Marinha/química , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Colesterol 7-alfa-Hidroxilase/genética , Colesterol 7-alfa-Hidroxilase/metabolismo , Dieta Hiperlipídica/efeitos adversos , Humanos , Hiperlipidemias/etiologia , Hiperlipidemias/genética , Hiperlipidemias/metabolismo , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de LDL/genética , Receptores de LDL/metabolismo , Receptores Depuradores/genética , Receptores Depuradores/metabolismo
10.
Food Funct ; 9(12): 6608-6617, 2018 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-30500001

RESUMO

Three new stilbenoids (1-3) and 16 known stilbenoids (4-6) and cannabinoids (7-19) were isolated from the leaves of hemp (Cannabis sativa L.). The structures of the three new compounds were identified as α,α'-dihydro-3',4,5'-trihydroxy-4'-methoxy-3-isopentenylstilbene (HM1), α,α'-dihydro-3,4',5-trihydroxy-4-methoxy-2,6-diisopentenylstilbene (HM2), and α,α'-dihydro-3',4,5'-trihydroxy-4'-methoxy-2',3-diisopentenylstilbene (HM3) by 1D and 2D NMR spectroscopy, LC-MS, and HRESIMS. The known α,α'-dihydro-3,4',5-trihydroxy-4,5'-diisopentenylstilbene (5) and combretastatin B-2 (6) were isolated for the first time from C. sativa f. sativa. These isolated compounds exhibited cytotoxic effects on human cancer cells via inhibiting the proliferation of cancer cells and inducing cell death. Among them, compounds 4, 5, 10, 12, 13, 15, and 19 displayed broad-spectrum cytotoxicity, and 1, 7, and 11 displayed selectivity in inhibition efficiency on MCF-7 and A549 cells, which suppressed the proliferation of cancer cells significantly by inducing cell death. The effects of compounds 1-3 on improving reverse cholesterol transport (RCT) were evaluated by isotope-tracing and western blotting. Results showed that the three stilbenoids showed a cytotoxicity above 1.0 mg L-1, especially that of HM3. They could improve [3H]-cholesterol efflux from Raw 264.7 macrophages to high density lipoproteins by enhancing the protein expression of ABCG1 and SR-B1, and HM1 and HM2 showed a significant difference compared with fenofibrate at 1.0 mg L-1. The three stilbenoids could also significantly improve the protein expression of ABCA1. Further study on HepG2 cells indicated that they improve the protein expression of LDLR, SR-B1 and CYP7A1, especially that of HM1 and HM3. However, they showed no significant effect on PCSK9. The above results indicated that these stilbenoids may elevate the transfer of cholesterol to hepatocytes by improving the protein expression of SR-B1 and LDLR, and the synthesis of bile acid by increasing the protein expression of CYP7A1. In conclusion, HM1 showed lower cytotoxicity and higher activity in improving the RCT-related protein expression. Our study suggests that it may be explored as a novel lipid-lowering drug and as a beneficial ingredient in health functional foods and pharmaceuticals.


Assuntos
Canabinoides/farmacologia , Cannabis/química , Colesterol/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Estilbenos/farmacologia , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Transporte Biológico/efeitos dos fármacos , Canabinoides/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Medicamentos de Ervas Chinesas/química , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Estrutura Molecular , Folhas de Planta/química , Receptores Depuradores Classe B/genética , Receptores Depuradores Classe B/metabolismo , Estilbenos/química
11.
J Neurophysiol ; 117(3): 1143-1155, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28031400

RESUMO

Spinal cord direct current stimulation (sDCS) has the potential for promoting motor function after injury through its modulatory actions on sensory processing, reflex functions, the motor cortex (M1) motor map, and motor output. Here we addressed systems-level mechanisms underlying sDCS neuromodulation of spinal circuits activated by M1 and peripheral forelimb electrical stimulation in anesthetized healthy rats. We determined the effects of cathodal and anodal sDCS (c- and a-sDCS) on local field potentials (LFP) and single-unit activity recorded at 32 sites simultaneously within the sixth cervical segment using a silicon multielectrode array. M1 stimulation produced distinctive dorsomedial and ventral LFP responses that showed polarity-dependent sDCS modulation. c-sDCS enhanced and a-sDCS depressed significantly ventral M1 responses; neither modulated dorsal responses significantly. Using evoked changes in ß- and γ-oscillations to assay network function, c-sDCS enhanced and a-sDCS reduced oscillation power ventrally. c-sDCS increased and a-sDCS decreased background firing and firing synchrony of recorded pairs of single units. Peripheral stimulation produced a region-dependent response that showed polarity-dependent sDCS modulation. The dorsomedial LFP was unaffected by c-sDCS and weakly suppressed with a-sDCS. Peripheral-evoked unit responses showed limited polarity dependence. Our findings stress that ventral motor network behavior is enhanced by the neuromodulatory actions of c-sDCS. The combined actions of c-sDCS on M1-evoked neural responses and network behavior in the cervical spinal cord help explain the reported enhanced motor effects of this neuromodulation approach and inform the mechanisms of sDCS for promoting motor rehabilitation after spinal cord or brain injury.NEW & NOTEWORTHY Spinal cord direct current stimulation (sDCS) modulates spinal functions and shows potential for neural rehabilitation after motor systems injury. Using a multichannel electrode array, we found that cathodal DCS enhanced, and anodal depressed, M1-evoked local field potentials, network oscillations, neuronal activity, and neuronal synchrony, especially in the ventral horn. With this new understanding, it is hoped that sDCS can be developed into a tunable spinal neuromodulatory tool for promoting function after brain or spinal injury.


Assuntos
Mapeamento Encefálico , Potencial Evocado Motor/fisiologia , Neurônios/fisiologia , Estimulação da Medula Espinal/métodos , Medula Espinal/citologia , Medula Espinal/fisiologia , Vias Aferentes/fisiologia , Análise de Variância , Animais , Biofísica , Ondas Encefálicas/fisiologia , Córtex Motor/fisiologia , Ratos , Ratos Sprague-Dawley , Análise Espectral
12.
Exp Neurol ; 277: 46-57, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26708732

RESUMO

An important strategy for promoting voluntary movements after motor system injury is to harness activity-dependent corticospinal tract (CST) plasticity. We combine forelimb motor cortex (M1) activation with co-activation of its cervical spinal targets in rats to promote CST sprouting and skilled limb movement after pyramidal tract lesion (PTX). We used a two-step experimental design in which we first established the optimal combined stimulation protocol in intact rats and then used the optimal protocol in injured animals to promote CST repair and motor recovery. M1 was activated epidurally using an electrical analog of intermittent theta burst stimulation (iTBS). The cervical spinal cord was co-activated by trans-spinal direct current stimulation (tsDCS) that was targeted to the cervical enlargement, simulated from finite element method. In intact rats, forelimb motor evoked potentials (MEPs) were strongly facilitated during iTBS and for 10 min after cessation of stimulation. Cathodal, not anodal, tsDCS alone facilitated MEPs and also produced a facilitatory aftereffect that peaked at 10 min. Combined iTBS and cathodal tsDCS (c-tsDCS) produced further MEP enhancement during stimulation, but without further aftereffect enhancement. Correlations between forelimb M1 local field potentials and forelimb electromyogram (EMG) during locomotion increased after electrical iTBS alone and further increased with combined stimulation (iTBS+c-tsDCS). This optimized combined stimulation was then used to promote function after PTX because it enhanced functional connections between M1 and spinal circuits and greater M1 engagement in muscle contraction than either stimulation alone. Daily application of combined M1 iTBS on the intact side and c-tsDCS after PTX (10 days, 27 min/day) significantly restored skilled movements during horizontal ladder walking. Stimulation produced a 5.4-fold increase in spared ipsilateral CST terminations. Combined neuromodulation achieves optimal motor recovery and substantial CST outgrowth with only 27 min of daily stimulation compared with 6h, as in our prior study, making it a potential therapy for humans with spinal cord injury.


Assuntos
Terapia por Estimulação Elétrica/métodos , Córtex Motor/fisiologia , Plasticidade Neuronal/fisiologia , Tratos Piramidais/fisiologia , Traumatismos da Medula Espinal/terapia , Medula Espinal/fisiologia , Animais , Axônios/patologia , Biotina/análogos & derivados , Biotina/metabolismo , Dextranos/metabolismo , Modelos Animais de Doenças , Eletrodos Implantados , Eletromiografia , Potencial Evocado Motor/fisiologia , Feminino , Membro Anterior/fisiopatologia , Lateralidade Funcional , Locomoção/fisiologia , Tratos Piramidais/lesões , Ratos , Ratos Sprague-Dawley , Vigília
13.
Brain Res ; 1625: 301-13, 2015 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-26348987

RESUMO

To further understand how tactile information is carried in somatosensory cortex (S1) and the thalamus (VPL), and how neuronal plasticity after neuroprosthetic stimulation affects sensory encoding, we chronically implanted microelectrode arrays across hand areas in both S1 and VPL, where neuronal activities were simultaneously recorded during tactile stimulation on the finger pad of awake monkeys. Tactile information encoded in the firing rate of individual units (rate coding) or in the synchrony of unit pairs (synchrony coding) was quantitatively assessed within the information theoretic-framework. We found that tactile information encoded in VPL was higher than that encoded in S1 for both rate coding and synchrony coding; rate coding carried greater information than synchrony coding for the same recording area. With the aim for neuroprosthetic stimulation, plasticity of the circuit was tested after 30 min of VPL electrical stimulation, where stimuli were delivered either randomly or contingent on the spiking of an S1 unit. We showed that neural encoding in VPL was more stable than in S1, which depends not only on the thalamic input but also on recurrent feedback. The percent change of mutual-information after stimulation was increased with closed-loop stimulation, but decreased with random stimulation. The underlying mechanisms during closed-loop stimulation might be spike-timing-dependent plasticity, while frequency-dependent synaptic plasticity might play a role in random stimulation. Our results suggest that VPL could be a promising target region for somatosensory stimulation with closed-loop brain-machine-interface applications.


Assuntos
Potenciais de Ação/fisiologia , Neurônios/fisiologia , Córtex Somatossensorial/fisiologia , Tálamo/fisiologia , Tato/fisiologia , Vigília , Animais , Estimulação Elétrica , Haplorrinos , Imageamento por Ressonância Magnética , Masculino , Microeletrodos , Vias Neurais , Estimulação Física , Estatísticas não Paramétricas
14.
J Hazard Mater ; 198: 143-50, 2011 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-22061441

RESUMO

Highly ordered mesoporous aluminas and calcium-doped aluminas were synthesized through a facile and reproducible method. Their fluoride adsorption characteristics, including adsorption isotherms, adsorption kinetics, the effect of pH and co-existing anions were investigated. These materials exhibited strong affinity to fluoride ions and extremely high defluoridation capacities. The highest defluoridation capacity value reached 450 mg/g. These materials also showed superb arsenic removal ability. 1g of mesoporous alumina was able to treat 200 kg of arsenic contaminated water with a pH value of 7, reducing the concentration of arsenate from 100 ppb to 1 ppb.


Assuntos
Óxido de Alumínio/química , Arsênio/isolamento & purificação , Fluoretos/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Transmissão , Termodinâmica
15.
Neural Plast ; 2011: 310737, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21949908

RESUMO

We will discuss some of the current issues in understanding plasticity in the sensorimotor (SM) cortices on the behavioral, neurophysiological, and synaptic levels. We will focus our paper on reaching and grasping movements in the rat. In addition, we will discuss our preliminary work utilizing inhibition of protein kinase Mζ (PKMζ), which has recently been shown necessary and sufficient for the maintenance of long-term potentiation (LTP) (Ling et al., 2002). With this new knowledge and inhibitors to this system, as well as the ability to overexpress this system, we can start to directly modulate LTP and determine its influence on behavior as well as network level processing dependent at least in part due to this form of LTP. We will also briefly introduce the use of brain machine interface (BMI) paradigms to ask questions about sensorimotor plasticity and discuss current analysis techniques that may help in our understanding of neuroplasticity.


Assuntos
Encéfalo/fisiologia , Aprendizagem/fisiologia , Córtex Motor/fisiologia , Plasticidade Neuronal/fisiologia , Córtex Somatossensorial/fisiologia , Animais , Humanos , Potenciação de Longa Duração/fisiologia , Córtex Motor/citologia , Córtex Motor/enzimologia , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/fisiologia , Ratos , Córtex Somatossensorial/citologia , Córtex Somatossensorial/enzimologia
17.
Sheng Li Xue Bao ; 58(2): 183-8, 2006 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-16628367

RESUMO

This paper presents a remote controlled multimode micro-stimulator based on the chip nRF24E1, which consists mainly of a micro-control unit (MCU) and a radio frequency (RF) transceiver. This micro-stimulator is very compact (18 mmx28 mm two layer printed circuit board) and light (5 g without battery), and can be carried on the back of a small animal to generate electrical stimuli according to the commands sent from a PC 10 meters away. The performance and effectiveness of the micro-stimulator were validated by in vitro experiments on the sciatic nerve (SN) of the frog, where action potentials (APs) as well as artifacts were observed when the SN was stimulated by the micro-stimulator. It was also shown by in vivo behavioral experiments on operant conditioned reflexes in rats which can be trained to obey auditory instruction cues by turning right or left to receive electrical stimulation ('virtual' reward) of the medial forebrain bundle (MFB) in a maze. The correct response for the rats to obey the instructions increased by three times and reached 93.5% in an average of 5 d. This micro-stimulator can not only be used for training small animals to become an 'animal robot', but also provide a new platform for behavioral and neurophysiological experiments.


Assuntos
Controle Comportamental/métodos , Condicionamento Operante/fisiologia , Estimulação Elétrica/instrumentação , Feixe Prosencefálico Mediano/fisiologia , Estimulação Acústica , Animais , Desenho de Equipamento , Masculino , Movimento , Ratos , Ratos Sprague-Dawley , Tecnologia de Sensoriamento Remoto , Robótica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA