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1.
Zhongguo Zhen Jiu ; 43(12): 1379-1383, 2023 Dec 12.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-38092535

RESUMO

OBJECTIVES: To observe the effects on cognitive function, sleep quality and hemodynamics in the patients with subjective cognitive decline (SCD) after treated with acupuncture at neck-Jiaji (EX-B 2) and tuina on the base of healthy lifestyle education and meta-memory training. METHODS: Sixty SCD patients were randomly divided into an observation group (30 cases, 1 case dropped out) and a control group (30 cases, 3 cases dropped out). In the control group, the healthy lifestyle education and meta-memory training was performed, twice daily, 15 min each time; the 5-day intervention was delivered a week, lasting consecutively 4 weeks. On the base of the intervention as the control group, in the observation group, acupuncture at neck-Jiaji (EX-B 2) and tuina was conducted. First, one-finger pushing and plucking method of tuina was exerted on the neck region along the running courses of the bladder meridian of foot-taiyang and the governor vessel, for 10 min to 15 min; afterwards, acupuncture was delivered at bilateral neck-Jiaji (EX-B 2), from C1 to C7; and the needles were retained for 30 min. This intervention was given once daily, 5 times a week, for consecutive 4 weeks. Before and after treatment, the score of the mini-mental state examination (MMSE), the score of full scale memory quotient (FSMQ) were assessed by Wechsler memory scale-fourth edition (WMS-Ⅳ) and the score of the Pittsburgh sleep quality index (PSQI) was compared between the two groups. Using transcranial Doppler ultrasound, the hemodynamic indexes (the mean velocity [Vm] and pulsatility index [PI] of the left vertebral artery [LVA], the right vertebral artery [RVA] and the basilar artery [BA]) were determined in the two groups. RESULTS: After treatment, the scores of MMSE and FSMQ increased compared with those before treatment in the two groups (P<0.05, P<0.001), PSQI score was lower (P<0.05) and Vm of BA was higher (P<0.001) in the observation group when compared with those before treatment. The scores of MMSE and FSMQ, as well as Vm of BA were higher (P<0.05, P<0.001), and PSQI score was decreased (P<0.05) in the observation group when compared with the control group. CONCLUSIONS: The combined therapy of acupuncture at neck-Jiaji (EX-B 2) and tuina is more advantageous to improving cognitive function, relieving chronic emotional stress and ameliorating sleeping quality in the patients with subjective cognitive decline, which may be achieved by improving the blood supply of the basilar artery.


Assuntos
Terapia por Acupuntura , Clorofenóis , Disfunção Cognitiva , Humanos , Terapia por Acupuntura/métodos , Disfunção Cognitiva/terapia , Cognição , Pontos de Acupuntura , Resultado do Tratamento
2.
Huan Jing Ke Xue ; 44(5): 2601-2612, 2023 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-37177934

RESUMO

In order to study the chemical characteristics and ion source of groundwater and further serve the scientific development and management of water resources in Shunping County. A total of 33 groups of karst water and 12 groups of pore water samples were collected systematically in Shunping County, and the hydrochemical types, composition characteristics, and main controlling factors of various types of groundwater were analyzed by using Gibbs diagram, ion ratio relation, and multivariate statistical analysis methods, and the contribution rates of various sources to groundwater solutes were evaluated. The results showed that the pore water and karst water in the study area were weakly alkaline, with TDS ranging from 245.89 to 430.00 mg·L-1 and 223.54 to 1347.80 mg·L-1, respectively. The anion components of groundwater were mainly HCO3- and Ca2+. Groundwater in the study area could be grouped into PW1 and PW2 pore water and KW1, KW2, and KW3 karst water. PW1 and KW1 were HCO3-Ca·Mg type, PW2 was HCO3·Cl-Ca·Mg type, KW2 was HCO3·NO3-Ca·Mg type, and KW3 was SO4-Ca·Mg type with high salinity. The weathering of carbonate rock mainly composed of dolomite and silicate rock mainly composed of albiar and potassium feldspar were the main material sources of groundwater, and their contributions to each water body were 39.69% to 66.13% and 11.87% to 58.38%. Sewage discharge and fertilizer use in human activities had significant effects on KW2 groundwater and PW1, PW2, and KW1 groundwater, respectively. In addition, the contribution rate of atmospheric precipitation to each water body ranged from 1.09% to 7.94% on average.

3.
Huan Jing Ke Xue ; 44(3): 1646-1656, 2023 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-36922225

RESUMO

At present, a large-scale relocation of industrial enterprises is taking place in major cities in China, and a large number of contaminated relocation sites are being generated, among which the heavy metal pollution is particularly serious. In order to analyze the pollution status, spatial distribution, and sources of heavy metals in the soil of a lead factory in Sanmenxia, the spatial variation and distribution characteristics of heavy metals in the soil were analyzed using geostatistics, and the main sources of heavy metals in the soil were analyzed using a PMF model. The results showed that the average values of As, Cd, Cu, Pb, Hg, and Ni in the soil far exceeded the background values of the soil environment in Henan province; the contents of As, Cd, Pb, and Hg exceeded the screening values of soil pollution risk; and the contents of As, Pb, and Hg exceeded the control values of soil pollution risk. The high-value area was located on the northern part of the slag yard; the Cr, Ni, and Cd high-value area was located in the north and south of the slag yard; the high-value As area was located in the slag yard between the southern area and the living quarters; the Cu and Pb high-value area was relatively scattered, mainly concentrated in the central part of the raw material storage area and furnace area; and Ni and Cd and Cu and Pb had the same spatial distribution characteristics. Based on the PMF model, it can be seen that there were three main sources of the seven heavy metals, and Cd was mainly from waste residue accumulation, with a contributing rate of 87.60%. Cu, Pb, and Hg were mainly soil parent material, with contribution rates of 92.50%, 75.20%, and 95.40%, respectively. Cr, Ni, and As were mainly raw material dust exhaust gas sources, with contribution rates of 80.80%, 83.30%, and 62.00%, respectively.

4.
Huan Jing Ke Xue ; 43(4): 2124-2132, 2022 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-35393836

RESUMO

Exploring the spatial distribution characteristics and variation law of soil pH and analyzing the impact of environmental factors on the spatial differentiation of soil pH are of great significance to the accurate management of soil pH and the sustainable utilization of soil resources in the complex mountainous environment of Anshun City. Based on 22 851 field sampling points, using the methods of global Moran's I index, cold and hot spot analysis, semi-variance function, and Kriging interpolation, the spatial structure characteristics and distribution law of soil pH in Anshun City were revealed from different angles, and the influence of environmental factors on its spatial differentiation was analyzed with the help of geographic detectors. The results showed that:① the variation range of topsoil pH value in Anshun City was 3.56-8.61, the mean value was 6.28, and the coefficient of variation was 16.33%. ② In the global space, soil pH showed aggregation distribution; in the local space, the west and northwest were hot spots, whereas the east and south were cold spots. The nugget coefficient (40.19%) showed that the spatial variability in soil pH was determined by both structural and random factors, but the role of structural factors was greater. ③ In terms of spatial distribution, soil pH mainly presented a patchy mosaic distribution pattern, in which slightly acidic soil (57.14%) was concentrated in the east, northeast, and south of Anshun City; neutral soil (30.13%) was concentrated in the west, northwest, and southeast; and strongly acidic soil (6.12%) and alkaline soil (6.45%) were embedded in slightly acidic soil and neutral soil, respectively, in a block structure. ④ The geo-detector analysis showed that the explanatory power of various environmental factors to the spatial variation in soil pH was ranked as soil type (9.4%)>soil forming parent rock (7.9%)>altitude (2.1%)>land use (1.8%)>slope (0.1%), in which the q value of the interaction between soil type and parent rock type and other factors was large. Therefore, soil type and parent rock type were the main controlling factors of soil pH spatial variation in Anshun City.


Assuntos
Solo , China , Cidades , Concentração de Íons de Hidrogênio , Solo/química , Análise Espacial
5.
Environ Sci Technol ; 55(17): 11612-11623, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34415770

RESUMO

Ultraviolet (UV)/chlorine draws increasing attention for the abatement of recalcitrant organic pollutants. Herein, it was found that TiO2 would significantly promote the degradation of dimethyl phthalate (DMP) in the UV/chlorine system (from 19 to 84%). Hydroxyl radicals (HO•) and chlorine radicals (Cl•) were the dominant reactive species for DMP degradation in the UV/chlorine/TiO2 system. Chlorine decayed much faster in UV/chlorine/TiO2 compared with UV/chlorine, which is possibly because photogenerated electrons (ecb-) and superoxide radicals (O2•-) have high reactivity with chlorine. As a result, the recombination of photogenerated holes (hvb+) and ecb- was inhibited and the accumulation of HO• and Cl• was facilitated. A kinetic model was established to simulate the reaction process, and it was found that the concentrations of HO• and Cl• were several times to dozens of times higher in UV/chlorine/TiO2 than that in UV/chlorine. The contributions of HO• and Cl• to DMP degradation were 70.3 and 29.7% by model simulation, respectively, and were close to the probe experiment result. In the UV/chlorine/TiO2 system, the degradation of DMP did not follow pseudo-first-order kinetics but the degradation of benzoate fitted well with pseudo-first-order kinetics. This phenomenon was elucidated by the structure of the pollutant and TiO2 and further tested by calculating the adsorption energy (Eads)/binding energy (Eb) with density functional theory. Due to faster decay of chlorine, lower amounts of disinfection byproducts formed in UV/chlorine/TiO2 compared with UV/chlorine. Adding TiO2 into the UV/chlorine system can promote the degradation of recalcitrant organic pollutants in an aqueous environment.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Cloro , Cinética , Oxirredução , Titânio , Raios Ultravioleta , Poluentes Químicos da Água/análise
6.
Stroke Vasc Neurol ; 6(4): 610-614, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33526630

RESUMO

BACKGROUND AND PURPOSE: Early haematoma expansion is determinative in predicting outcome of intracerebral haemorrhage (ICH) patients. The aims of this study are to develop a novel prediction model for haematoma expansion by applying deep learning model and validate its prediction accuracy. METHODS: Data of this study were obtained from a prospectively enrolled cohort of patients with primary supratentorial ICH from our centre. We developed a deep learning model to predict haematoma expansion and compared its performance with conventional non-contrast CT (NCCT) markers. To evaluate the predictability of this model, it was also compared with a logistic regression model based on haematoma volume or the BAT score. RESULTS: A total of 266 patients were finally included for analysis, and 74 (27.8%) of them experienced early haematoma expansion. The deep learning model exhibited highest C statistic as 0.80, compared with 0.64, 0.65, 0.51, 0.58 and 0.55 for hypodensities, black hole sign, blend sign, fluid level and irregular shape, respectively. While the C statistics for swirl sign (0.70; p=0.211) and heterogenous density (0.70; p=0.141) were not significantly higher than that of the deep learning model. Moreover, the predictive value for the deep learning model was significantly superior to that of the logistic model of haematoma volume (0.62; p=0.042) and the BAT score (0.65; p=0.042). CONCLUSIONS: Compared with the conventional NCCT markers and BAT predictive model, the deep learning algorithm showed superiority for predicting early haematoma expansion in ICH patients.


Assuntos
Aprendizado Profundo , Hemorragia Cerebral/diagnóstico por imagem , China , Hematoma/diagnóstico por imagem , Humanos , Tomografia Computadorizada por Raios X
8.
Int Immunopharmacol ; 68: 74-80, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30612087

RESUMO

Osteoarthritis (OA) is the most common inflammatory joint disease that is mainly characterized by articular cartilage destruction. Forkhead box M1 (FOXM1) is a transcription factor that acts as a critical mediator of inflammatory response. However, the role of FOXM1 in OA has not been investigated. Interleukin (IL)-1ß is a major proinflammatory cytokine, which is associated with cartilage destruction in the pathophysiology of OA. In the present study, we used IL-1ß to stimulate chondrocytes for the establishment of OA in vitro model. We found that FOXM1 was up-regulated in IL-1ß-induced chondrocytes. Knockdown of FOXM1 attenuated IL-1ß-caused decrease in cell viability. Knockdown of FOXM1 suppressed the IL-1ß-induced production of inflammatory cytokines including tumor necrosis factor (TNF)-α, and IL-6. Besides, several inflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthases (iNOS), and cyclooxygenase-2 (COX-2) were also repressed by knockdown of FOXM1. FOXM1 silencing also inhibited the production of matrix metalloproteinases (MMPs) including MMP-3 and MMP-13. Furthermore, we found that knockdown of FOXM1 blocked the IL-1ß-induced NF-κB activation in chondrocytes. These findings indicated that FOXM1 might play an important role in the pathogenesis of OA, suggesting that FOXM1 might be a potential therapeutic target for the treatment of OA.


Assuntos
Condrócitos/imunologia , Citocinas/imunologia , Proteína Forkhead Box M1/imunologia , Osteoartrite/imunologia , Células Cultivadas , Proteína Forkhead Box M1/genética , Inativação Gênica , Humanos , NF-kappa B/imunologia , RNA Interferente Pequeno/genética
9.
Huan Jing Ke Xue ; 39(6): 2991-3002, 2018 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965659

RESUMO

UV filters have been widely used in sunscreen products, and they have partially ended up in the marine environment via human recreational activities and sewage treatment plant drainage, becoming one of the emerging marine pollutants. As UV filters have many characteristics, such as extensive use, continuous emissions, and stability, their potential risks to the environment and ecology have become a hot topic in the field of environmental research all over the world. This study analyzed the environmental behavior of UV filters in the ocean, such as migration, transformation, and volatilization. The toxic effects (i. e., growth inhibition, reproductive inhibition, death, and malformation) of the inorganic (mainly nano-TiO2 and nano-ZnO) and organic UV filters (mainly benzophenones, camphor derivatives, and cinnamic acids) on marine organisms (i. e., algae, seashell, fish, coral, and sea urchin) were summarized. The research also analyzed the inherent toxicity mechanisms from the perspective of oxidative damage, neurotoxicity, and endocrine disability. The prospect and future directions in this field were also discussed. This review provides a reference for scientific research and pollution control related to UV filters.


Assuntos
Protetores Solares/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/efeitos dos fármacos , Benzofenonas/toxicidade , Cânfora/toxicidade , Cinamatos/toxicidade
10.
China Journal of Endoscopy ; (12): 95-97, 2017.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-661140

RESUMO

Objective To investigate the indication and clinical experience of laparoscopic subtotal cholecystectomy. Methods We performed a retrospective analysis on the clinical data of 468 patients who underwent laparoscopic subtotal cholecystectomy from January 2012 to December 2015. Results There were no deaths. 7 cases that underwent laparoscopic cholecystectomy were converted to open surgery with laparoscopic subtotal cholecystectomy. 5 cases that were diagnosed with Mirizzi syndrome (3 cases with type I and 2 with type II) and 456 cases underwent laparoscopic subtotal cholecystectomy. No severe complication was detected after surgery. 16 cases with biliary leakage and 2 with duodenum leakage. The patients got recovered after a short time of drainage. 362 cases were followed up and the median follow-up time was (21.0 ± 4.9) months. 18 ones were with dyspepsia and 11 ones with upper or right upper discomfort. Conclusion Laparoscopic subtotal cholecystectomy was a safe choice and avoided injury of biliary duct for patients with severe adhesion of calot's triangle. The biliary leakage should be mainly observed during and after surgery.

11.
China Journal of Endoscopy ; (12): 95-97, 2017.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-658259

RESUMO

Objective To investigate the indication and clinical experience of laparoscopic subtotal cholecystectomy. Methods We performed a retrospective analysis on the clinical data of 468 patients who underwent laparoscopic subtotal cholecystectomy from January 2012 to December 2015. Results There were no deaths. 7 cases that underwent laparoscopic cholecystectomy were converted to open surgery with laparoscopic subtotal cholecystectomy. 5 cases that were diagnosed with Mirizzi syndrome (3 cases with type I and 2 with type II) and 456 cases underwent laparoscopic subtotal cholecystectomy. No severe complication was detected after surgery. 16 cases with biliary leakage and 2 with duodenum leakage. The patients got recovered after a short time of drainage. 362 cases were followed up and the median follow-up time was (21.0 ± 4.9) months. 18 ones were with dyspepsia and 11 ones with upper or right upper discomfort. Conclusion Laparoscopic subtotal cholecystectomy was a safe choice and avoided injury of biliary duct for patients with severe adhesion of calot's triangle. The biliary leakage should be mainly observed during and after surgery.

12.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 44(1): 90-4, 2015 01.
Artigo em Chinês | MEDLINE | ID: mdl-25851982

RESUMO

OBJECTIVE: To investigate the effect of occlusal reconstruction on blood flow velocity and cerebral oxygen saturation in patients with malocclusion. METHODS: Thirty-three patients with malocclusion treated with occlusal reconstruction in Department of Stomatology, Medical School of Huzhou Normal College from Feb 2011 to Oct 2013 were enrolled in the study. The systolic peak flow velocity (vs), end-diastolic peak flow (vd) , mean peak flow velocity (vm) of middle cerebral artery and the oxygen saturation (rScO2) in the brain were detected at rest or chewing status by using transcranial Doppler color ultrasonography and near-infrared spectroscopy, respectively. RESULTS: In rest state, vm was significantly increased on 3 months after treatment, while vs and vd were significantly increased on 6 months after treatment and rScO2 were increased on 12 months after treatment (P<0.05). In chewing state, vs, vm, and rScO2 were increased on 3 months after treatment, and vd was increased on 6 months after treatment (P<0.05). CONCLUSION: Occlusal reconstruction can increase blood flow velocity of middle cerebral artery and cerebral oxygen saturation and improve oxygen supply of the brain in patients with malocclusion.


Assuntos
Circulação Cerebrovascular , Má Oclusão/cirurgia , Oxigênio/fisiologia , Procedimentos de Cirurgia Plástica , Velocidade do Fluxo Sanguíneo , Encéfalo/irrigação sanguínea , Encéfalo/fisiologia , Humanos , Ultrassonografia Doppler Transcraniana
13.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 43(4): 434-40, 2014 07.
Artigo em Chinês | MEDLINE | ID: mdl-25187458

RESUMO

OBJECTIVE: To construct human phage single-chain antibody (scFv) library against breast cancer, and to identify anti-HER2 specific antibodies from the human phage display scFv library to offer a stronger affinity sequence targeting HER2 for fusion protein targeting HER2 and CXCR4. METHODS: Total RNA was extracted from the adjacent lymphatic tissue harvested from breast cancer patients. The variable regions of the whole antibody were amplified by using RT-PCR and were cloned into the vector pCANTAB-5E through a linker. The products were electroporated into competent E.coli TG1 cells. Recombinant phages specific for breast cancer cells were enriched in SKBR-3 after four rounds. The antigen-positive clones were selected by ELISA and immunohistochemistry. RESULTS: The fragment of VH and VL were about 375 and 330 bp and were linked in vitro to form scFv of 750 bp that was resistant to the breast cancer HER2 single strand. A fusion phage display library that contained total of 2.48×10(8) pfu /ml was established. ELISA and immunohistochemical results confirmed that the antibody has a strong affinity with HER2 antigen in breast cancer tissue. Compared to human IgG antibody, a scFv phage library against human breast cancer was successfully constructed with high capacity. The scFv was highly specific to HER2 antigen and the sequencing results indicated that VL and VH genes were highly homologous with the variable region of human antibody. CONCLUSION: This strategy may achieve new targeted antibody resistant to the breast cancer for clinical treatment and provide a carrier that uses HER2 as a target of the fusion protein for anti-tumor therapy.


Assuntos
Neoplasias da Mama/imunologia , Biblioteca de Peptídeos , Receptor ErbB-2/imunologia , Anticorpos de Cadeia Única/imunologia , Neoplasias da Mama/genética , Feminino , Humanos
14.
J Inorg Biochem ; 140: 64-71, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25063909

RESUMO

A pair of symmetrical furyl based ruthenium(II) complexes ([Ru(phen)2dpq-df](2+) (1) and [Ru(bpy)2dpq-df](2+) (2) (phen=1,10-phenanthroline, bpy=2,2'-bipyridine, dpq-df=dipyrido (3,2-a:2',3'-c) quinoxaline-difuran) have been prepared and characterized. The binding properties of both complexes toward G-quadruplex DNA have been investigated by fluorescence spectroscopy, UV-Vis spectroscopy, circular dichroism (CD), fluorescence resonance energy transfer (FRET) melting assays and molecular docking studies. The experimental results indicated that both Ru-complexes exhibited a remarkable "light switch" effect in the presence of hybrid G-quadruplex DNA. Interestingly, the "light switch" can be repeated off and on through the successive addition of Cu(2+) ions and EDTA, and all these behaviors can be observed even by the naked eyes. Moreover, FRET melting assay revealed that both complexes could be potential stabilizers for G-quadruplex architectures. The computational studies not only confirmed that the two complex molecules bound to one G-quadruplex DNA molecule, but also explained the "light switch" effect.


Assuntos
Quadruplex G , Compostos de Rutênio/química , Dicroísmo Circular , Transferência Ressonante de Energia de Fluorescência , Simulação de Acoplamento Molecular , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
15.
J Environ Qual ; 42(1): 103-10, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23673744

RESUMO

To determine the effects of parent material and land use on the concentration of trace elements in the agricultural topsoil of Guizhou Province, China, a total of 584 agricultural topsoil samples were collected in a typical region. The results indicate that the contents of trace elements (As, Cd, Cr, Hg, and Pb) in agricultural soils were greater than in the uncultivated soils, and the paddy fields exhibited higher contents of trace elements than dry lands. The enrichments of most trace elements in agricultural topsoil derived from carbonate rock were more serious. In paddy fields, Cd, Cr, and As showed positive relationships with soil organic matter ( < 0.01) but were not affected by pH, carbon-to-nitrogen (C/N) ratio, and clay ( > 0.05). Lead and Hg formed the second component in principal component analysis (PCA) and were closely related to pH and clay content. In dry lands, the trace elements were well correlated with pH, C/N, and clay ( < 0.05). Analysis of PCA and correlation showed that Cd, Cr, and Hg were mainly derived from inorganic fertilizers, whereas Pb and As were primarily from organic manures. These results suggest that the effect of anthropogenic activities on paddy fields is more serious than on dry lands. Parent materials not only serve as sources of soil trace elements but also control the loss and accumulation of trace elements by affecting soil physicochemical properties, especially in dry lands.


Assuntos
Poluentes do Solo , Oligoelementos , Agricultura , Monitoramento Ambiental , Pais , Solo/química
16.
Chin Med J (Engl) ; 124(10): 1590-2, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21740825

RESUMO

Migration of a bullet to a distant part of the body after a gunshot is rarely observed in the clinical setting, and migration to the heart is even rarer. There are usually no clear symptoms or signs from migration of a bullet. The bullet can be easily missed and sometimes identified in a review examination. A case of bullet migration to the heart 2 months after a gunshot to the left knee was reported.


Assuntos
Traumatismos Cardíacos/etiologia , Joelho/patologia , Ferimentos por Arma de Fogo , Adulto , Traumatismos Cardíacos/patologia , Humanos , Masculino
17.
J Neurosci ; 31(9): 3328-35, 2011 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-21368044

RESUMO

Spaced patterns of repetitive synaptic activation often result in a long-lasting, protein synthesis-dependent potentiation of synaptic transmission, known as late-phase long-term potentiation (L-LTP) that may serve as a substrate for long-term memory. Behavioral studies showed that posttraining blockade of NMDA subtype of the glutamate receptor (NMDAR) impaired long-term memory, although NMDAR activation is generally known to be required during LTP induction. In this study, we found that the establishment of L-LTP in vivo requires NMDAR activation within a critical time window after LTP induction. In the developing visual system of Xenopus laevis tadpole, L-LTP of retinotectal synapses could be induced by three episodes of theta burst stimulation (TBS) of the optic nerve with 5 min spacing ("spaced TBS"), but not by three TBS episodes applied en masse or spaced with intervals ≥10 min. Within a time window of ∼30 min after the spaced TBS, local perfusion of the tectum with NMDAR antagonist d-AP5 or Ca(2+)-chelator EGTA-AM impaired the establishment of L-LTP, indicating the requirement of postinduction activation of NMDAR/Ca(2+) signaling. Moreover, inhibiting spontaneous spiking activity in the tectum by local application of tetrodotoxin (TTX) prevented L-LTP when TTX was applied for 15 min immediately after the spaced TBS but not 1 h later, whereas the same postinduction TTX application in the retina had no effect. These findings offer new insights into the synaptic basis for the requirement of postlearning activation of NMDARs and point to the importance of postlearning spontaneous circuit activity in memory formation.


Assuntos
Potenciação de Longa Duração/fisiologia , Receptores de N-Metil-D-Aspartato/metabolismo , Retina/crescimento & desenvolvimento , Colículos Superiores/crescimento & desenvolvimento , Sinapses/fisiologia , Potenciais Sinápticos/fisiologia , Potenciais de Ação/fisiologia , Animais , Estimulação Elétrica/métodos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Receptores de N-Metil-D-Aspartato/fisiologia , Retina/citologia , Retina/metabolismo , Colículos Superiores/citologia , Colículos Superiores/metabolismo , Xenopus laevis
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