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1.
Rev Sci Instrum ; 94(12)2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38109469

RESUMO

An E-band (60-90 GHz) multi-channel Doppler backscattering (DBS) system with X-mode polarization has been installed on the Experimental Advanced Superconducting Tokamak (EAST), which can measure the turbulence at five different radial locations simultaneously. This system can launch 31 fixed microwave frequencies in the range of 60-90 GHz with a 1 GHz interval into the plasma, and five probing signals are selected by employing a reference signal and multiple filters. During experiments, the frequency of the reference signal is tunable in the E-band, and the selected probing signals can be changed as needed without any other adjustments, which can be performed in one shot or between shots. Furthermore, the incident angle can be adjusted from -10° to 20°, and the wavenumber range is 4-25 cm-1 with a wavenumber resolution of Δk/k ≤ 0.35. Ray tracing simulations are employed to calculate the scattering locations and the perpendicular wavenumber. In this article, the hardware design, ray tracing, and initial results obtained from the EAST plasma will be presented.

2.
Eur Rev Med Pharmacol Sci ; 27(17): 8144-8153, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37750642

RESUMO

OBJECTIVE: The Naples prognostic score (NPS) is a newly developed indicator of inflammation and nutritional status. However, its role in predicting the prognosis of lung cancer is unclear. We hereby reviewed the association between NPS and outcomes of lung cancer. MATERIALS AND METHODS: PubMed, Web of Science, Embase, and Google Scholar were searched up to 15th April 2023 for studies assessing the predictive role of NPS for overall survival (OS) and disease-free survival (DFS) in lung cancer. RESULTS: Seven studies were included. All were from China. One study was on small cell lung cancer, while the rest were on non-small cell lung cancer. Meta-analysis demonstrated that a high NPS score was a significant predictor of OS (HR: 3.21 95% CI: 2.27, 4.54 I2=62%) and disease-free survival (DFS) (HR: 3.81 95% CI: 2.57, 5.64 I2=65%) in lung cancer patients. Subgroup analysis based on different NPS reference values also showed similar results. The results remained significant on sensitivity analysis. CONCLUSIONS: The NPS is a strong and independent prognostic indicator of lung cancer patients. Higher NPS scores are associated with worse OS and DFS. Further studies from non-Chinese populations are needed to supplement the results.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Humanos , Neoplasias Pulmonares/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Prognóstico , Intervalo Livre de Doença
4.
Zhonghua Liu Xing Bing Xue Za Zhi ; 39(10): 1375-1380, 2018 Oct 10.
Artigo em Chinês | MEDLINE | ID: mdl-30453440

RESUMO

Objective: To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS), isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. Methods: Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS. Eleven currently known SAg genes including SpeA, speC, speG, speH, speI, speJ, speK, speL, speM, smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR. Results: A total of 377 GAS were isolated from 6 801 throat swab specimens, with the positive rate as 5.5%. There were obvious changes noticed among speC, speG, speH and speK in three years. A total of 45 SAg genes profiles were observed, according to the SAgs inclusion. There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emm1 and emm12 strains (χ(2)=38.196, P<0.001; χ(2)=72.310, P<0.001). There also appeared significant differences in the frequencies of speA, speH, speI and speJ between emm1 and emm12 strains (χ(2)=146.154, P<0.001; χ(2)=52.31, P<0.001; χ(2)=58.43, P<0.001; χ(2)=144.70, P<0.001). Conclusions: Obvious changes were noticed among SAg genes including speC, speG, speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. SAg genes including speA, speH, speI and speJ appeared to be associated with the emm 1 and emm 12 strains. More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles, during the epidemic period.


Assuntos
Antígenos de Bactérias/genética , Faringite/diagnóstico , Complicações Infecciosas na Gravidez/microbiologia , Escarlatina/diagnóstico , Streptococcus pyogenes/genética , Streptococcus pyogenes/isolamento & purificação , Superantígenos/genética , Proteínas da Membrana Bacteriana Externa , Proteínas de Bactérias , Pequim/epidemiologia , China/epidemiologia , Exotoxinas , Feminino , Humanos , Proteínas de Membrana , Faringite/epidemiologia , Faringite/microbiologia , Faringe/microbiologia , Gravidez , Reação em Cadeia da Polimerase em Tempo Real , Escarlatina/genética , Escarlatina/microbiologia , Infecções Estreptocócicas , Streptococcus pyogenes/imunologia
5.
Zhonghua Liu Xing Bing Xue Za Zhi ; 39(8): 1096-1099, 2018 Aug 10.
Artigo em Chinês | MEDLINE | ID: mdl-30180435

RESUMO

Objective: To establish a classified evaluation system for recognizing the levels of influenza epidemics and to explore the new reporting system on influenza epidemics. Methods: The following 3 indicators, including 1) the number of influenza-like illness, 2) positive rate of detection on influenza virus nucleic acids, and 3) the number of influenza outbreaks were chosen to calculate the synthetic index and to classify the grades of evaluation. Results: 209 weeks during 2013-2017 were classified into 5 grades: Grade 1 were 110 weeks (52.63%), Grade 2 were 47 weeks (22.49%), Grade 3 were 44 weeks (21.05%), Grade 4 were 8 weeks (3.83%), and Grade 5 were 0 week. Conclusion: This classified evaluation system provided simple, comprehensive and comparable reference indicators and used for the evaluation on influenza epidemics, also providing suggestions for influenza prevention and control accordingly.


Assuntos
Surtos de Doenças , Influenza Humana/epidemiologia , Vigilância da População , Pequim/epidemiologia , Epidemias , Humanos , Viroses
6.
Eur Rev Med Pharmacol Sci ; 22(9): 2580-2587, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29771443

RESUMO

OBJECTIVE: The purpose of this study was to detect ferritin light chain (FTL) expression level in osteosarcoma (OS), and to clarify whether FTL could offer additional help in diagnosis or therapy. MATERIALS AND METHODS: First, we assessed FTL level in OS tissues and cells through GEO dataset and tissue microarrays (TMAs). Then, we overexpressed FTL expression in MG-63 cell line. Lastly, we detected the expression of EMT-related signal pathway proteins to study its underlying molecular mechanisms. RESULTS: GEO dataset and TMAs showed that FTL was down-regulated in OS. After FTL was overexpressed, the proliferation, migration and invasion abilities of OS cells were significantly reduced. Moreover, after FTL overexpressing, the levels of CDH2 and Vimentin were down-regulated with CDH1 up-regulated. CONCLUSIONS: We revealed that FTL (1) is lower in OS then in normal tissue, (2) is related to metastasis, survival period, and therapeutic response, and (3) may be a tumor-inhibiting factor owing to its inhibition of EMT in OS.


Assuntos
Apoferritinas/metabolismo , Neoplasias Ósseas/metabolismo , Transição Epitelial-Mesenquimal , Osteossarcoma/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD/metabolismo , Apoferritinas/genética , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Caderinas/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Criança , Regulação para Baixo , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Osteossarcoma/genética , Osteossarcoma/patologia , Transdução de Sinais , Vimentina/metabolismo , Adulto Jovem
7.
Zhonghua Yu Fang Yi Xue Za Zhi ; 51(9): 832-836, 2017 Sep 06.
Artigo em Chinês | MEDLINE | ID: mdl-28881550

RESUMO

Objective: To analyze the prevalence and drug resistance of mycoplasma pneumoniae in patients with community-acquired pneumonia during 2011-2015 in Beijing. Methods: Totally 2 272 mycoplasma pneumoniae samples were collected from patients with community-acquired pneumonia in 5 sentinel hospitals during 2011-2015. Mycoplasma pneumoniae were detected by real-time PCR. 142 copies of positive samples with Ct value under 30 were cultured to get the strains so that the genotypes based on the P1 gene sequence and the drug resistance based on the in vitro drug resistance test could be conducted. χ(2) test was used to compare the detection rates of mycoplasma pneumoniae among different age groups and different onset-phase. Results: The positive rate of mycoplasma pneumoniae was 13.6%(308 cases). The positive rate in groups aging (5-14), (15-24) and ≥60 years old were separately 24.4% (67/275), 24.4% (38/156) and 3.9% (28/727) (χ(2)=1.22, P<0.001). The annual detection rate of mycoplasma pneumoniae in 2011-2015 were 14.6% (73/501), 10.2% (36/353), 26.4% (101/383), 10.3% (41/398), 9.0% (57/637),respectively (χ(2)=72.65, P<0.001). Seasonally, the peak of positive rate was between October and December (17.5%, 122/699) and the lowest positive rate was between April and June (8.6%, 43/502). 36 strains were isolated from 142 swabs and 23 (63.9%) were P1-Ⅰ and 13 (36.1%) were P1-Ⅱ by genotyping. All isolates were susceptible to the fluoroquinolones (levofloxacin, ciprofloxacin, and gatifloxacin) and tetracycline. All P1-Ⅱ strains were susceptible to macrolides while most of the P1-Ⅰ strains (22 strains) were macrolide-resistant. Conclusion: People aging (5-14) and (15-24) years old were more susceptible to mycoplasma pneumoniae in patients with community-acquired pneumonia in Beijing between 2011 and 2015. The highest positive rate of mycoplasma pneumoniae was in 2013 and the case distributed in all seasons. The major popular genotype was P1-Ⅰ, whose strains were mostly macrolide-resistant.


Assuntos
Antibacterianos/farmacologia , Infecções Comunitárias Adquiridas/tratamento farmacológico , Farmacorresistência Bacteriana , Mycoplasma pneumoniae/efeitos dos fármacos , Pneumonia por Mycoplasma/tratamento farmacológico , Adolescente , Pequim/epidemiologia , Criança , Pré-Escolar , Infecções Comunitárias Adquiridas/epidemiologia , Humanos , Pessoa de Meia-Idade , Pneumonia por Mycoplasma/epidemiologia , Adulto Jovem
8.
Water Sci Technol ; 67(3): 477-84, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23202550

RESUMO

In the present study, nano-sized TiO(2)/Al(2)O(3) modified polyvinylidene fluoride (PVDF) membranes (MM) were fabricated and then utilized for oil/water emulsion separation. The results showed that, compared with PVDF membrane (OM), the contact angle of MM decreased and hydrophilicity increased. The ultrafiltration (UF) of oil in water emulsions with transmembrane pressure (TMP) increasing results in a sharp fall in relative flux with time. The cake filtration models did not always predict the performance over the complete range of filtration times very well. In the initial 30 min, all the four cake models can simulate this UF process to a certain extent, and the suitability was: cake filtration > intermediate pore blocking > standard pore blocking > complete pore blocking models. However, they were no longer adapted well with UF time extent to 60 min, but only cake filtration (R(2) = 0.9535) maintained a high adaptability. Surface and cross-sectional morphology of the membrane was investigated by SEM to make an advanced certificate of this UF mechanism.


Assuntos
Óxido de Alumínio/química , Membranas Artificiais , Nanopartículas/química , Polivinil/química , Titânio/química , Purificação da Água , Incrustação Biológica , Modelos Teóricos , Ultrafiltração/instrumentação
9.
Water Sci Technol ; 64(9): 1892-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22020484

RESUMO

Polyvinylidene fluoride (PVDF) flat ultrafiltration membranes modified by nano-sized alumina (Al2O3) particles were prepared by phase inversion process and their properties and anti-fouling performances were examined. The influence of three types of natural organic matters on the modified membrane fouling was also studied. Raw water was taken from two different locations, i.e., Harbin and Zhaoyuan, of Songhua River. Dissolved organic compounds in the raw water were fractionated using XAD resins into three fractions, i.e., hydrophobic fraction, transphilic fraction, and hydrophilic fraction (HPI). The three adsorbed compounds were further eluted and dissolved into distilled water respectively to prepare the feed for the fouling tests. All solutions were adjusted to a concentration of 10.6 mg C/L, which equals to the total organic carbon (TOC) of the raw water. Results show that the addition of nano-Al2O3 particulars did not affect the inherent traits of the PVDF membranes, however, its surface hydrophilic properties were improved significantly with the addition of nanoparticles and anti-fouling performance was enhanced as well. The HPIs in the Songhua River were the main foulant, causing more fouling to membrane than hydrophobic and transphilic matters.


Assuntos
Óxido de Alumínio/química , Incrustação Biológica/prevenção & controle , Membranas Artificiais , Nanopartículas/química , Polivinil/química , Rios/química , Ultrafiltração/métodos , Fracionamento Químico , China , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Microscopia de Força Atômica , Compostos Orgânicos/química , Poluentes Químicos da Água/análise , Purificação da Água , Qualidade da Água
10.
J Hazard Mater ; 193: 37-44, 2011 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-21872396

RESUMO

This paper studies the cumulative effect of various parameters, namely anionic polyacrylamide (APAM) concentration, oil concentration, pH, trans-membrane pressure (TMP), and total dissolved solid (TDS), and obtains optimal parameters for the minimum relative flux (J/J(0)) declining in aqueous solutions with response surface methodology (RSM). In order to analyze the mutual interaction and optimal values of parameters affecting ultrafiltration, a central composite rotatable design (CCRD), one method of RSM, was employed. The analysis of variance (ANOVA) of the cubic polynomial model demonstrated that this model was highly significant and reliable. The results show that the effect of APAM and oil on J/J(0) has an inverse trend with pH value increasing. Moreover, the mutual interaction of initial APAM (oil) concentration (C(APAM(oil))) and pH (TMP) were negligible, while the mutual interaction of C(APAM) and C(oil) has an obvious effect, i.e. the effect of initial feed C(APAM) became more important at higher values of initial feed C(oil), and the J/J(0) was only about 4%. The favorable operate conditions in this ultrafiltration process were at low C(APAM), C(oil), pH, and TMP, which agreed with the conclusions of many authors, while considering water production, C(APAM) and C(oil) < 50 mg/L, pH < 4, and TMP < 0.075 MPa could be accepted.


Assuntos
Óxido de Alumínio/química , Membranas Artificiais , Nanotecnologia , Polivinil/química , Titânio/química , Ultrafiltração/métodos , Análise de Variância , Emulsões , Concentração de Íons de Hidrogênio , Soluções , Propriedades de Superfície
11.
J Hazard Mater ; 189(1-2): 495-501, 2011 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-21398032

RESUMO

To determine the isotherm parameters and kinetic parameters of adsorption of anion polyacrylamide (APAM) from aqueous solution on PVDF ultrafiltration membrane (PM) and modified PVDF ultrafiltration membrane (MPM) is important in understanding the adsorption mechanism of ultrafiltration processes. Effect of variables including adsorption time, initial solution concentration, and temperature were investigated. The Redlich-Peterson equation of the five different isotherm models we chose was the most fitted model, and the R(2) was 0.9487, 0.9765 for PM and MPM, respectively; while, the pseudo-first-order model was the best choice among all the four kinetic models to describe the adsorption behavior of APAM onto membranes, suggesting that the adsorption mechanism was a chemical and physical combined adsorption on heterogeneous surface. The thermodynamic parameters were also calculated from the temperature dependence (Δ(r)G(m)(θ), Δ(r)H(m)(θ), Δ(r)S(m)(θ)), which showed that the process of adsorption is not spontaneous but endothermic process and high temperature favors the adsorption.


Assuntos
Resinas Acrílicas/isolamento & purificação , Membranas Artificiais , Adsorção , Filtração , Cinética , Polivinil , Soluções , Temperatura , Termodinâmica
12.
Epidemiol Infect ; 139(1): 52-8, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20854713

RESUMO

In order to determine the prevalence of antibody against 2009 H1N1 influenza in Beijing, we conducted a serological survey in 710 subjects, 1 month after the epidemic peak. We found that 13·8% of our cohort was seropositive. Subjects aged ≥60 years recorded the lowest seroprevalence (4·5%). The age-weighted seroprevalence of 14·0% was far lower than the supposed infection rate at the epidemic peak, derived from the basic reproduction number for 2009 H1N1 virus. For subjects who had received the pandemic vaccine seroprevalence was 51·4%. In subjects aged ≥60 years the seasonal influenza vaccination was not significantly associated with being seropositive. Our study suggests that many factors, and not just the immunological level against 2009 H1N1 influenza in the community, affected the spread of the virus within the population of Beijing.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/epidemiologia , Adolescente , Adulto , Distribuição por Idade , Criança , Pré-Escolar , China/epidemiologia , Estudos de Coortes , Feminino , Humanos , Lactente , Recém-Nascido , Influenza Humana/sangue , Influenza Humana/imunologia , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Razão de Chances , Estudos Soroepidemiológicos , Adulto Jovem
13.
Tissue Antigens ; 66(3): 248-50, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16101839

RESUMO

A novel human leucocyte antigen-DRB1*16 (HLA-DRB1*16) allele (DRB1*1609) has been identified by sequencing-based typing (SBT) in Chinese Han population. This new allele has identical nucleotide sequence to DRB1*160101 in exon 2, except for a single-nucleotide substitution from A to T at position 127. This change leads to an amino acid change from tyrosine to phenylalanin at residue 47 (Y47F). SBT was performed for cloned DRB1*16-specific polymerase chain reaction fragment. The serological phenotype of DRB1*1609 is equivalent to DR16 antigen.


Assuntos
Antígenos HLA-DR/genética , Alelos , Sequência de Bases , China , Éxons , Saúde da Família , Feminino , Cadeias HLA-DRB1 , Teste de Histocompatibilidade , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Fenótipo , Fenilalanina/química , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Tirosina/química
14.
Tissue Antigens ; 66(2): 148-50, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16029438

RESUMO

A novel HLA-B*07 allele, B*0740, has been identified by sequence-based typing (SBT) in the Chinese Han population. This new allele is identical to B*0705 and B*0706 for exons 2, 3, and 4, except for a single nucleotide at position 605 of codon 202 in exon 3 (AAG-->ATG) leading to an amino acid change from lysine to methionine. SBT was performed following allele separation using the Haploprep method. The serological equivalence of B*0740 to the B7 antigen did not change.


Assuntos
Alelos , Antígenos HLA-B/genética , Sequência de Aminoácidos , Povo Asiático , Sequência de Bases , Éxons , Variação Genética , Antígeno HLA-B7 , Antígenos HLA-DR/genética , Antígenos HLA-DR/imunologia , Cadeias HLA-DRB1 , Teste de Histocompatibilidade , Humanos , Dados de Sequência Molecular , Mutação Puntual
15.
Synapse ; 39(2): 133-8, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11180500

RESUMO

Interspike intervals (ISIs) of dopamine (DA) neurons recorded in the substantia nigra are predicted partially by their immediate prior history. This study was designed to assess neuroanatomic origins of these sequential relationships. ISI data recorded from three groups of nigral DA neurons were studied: 1) 16 neurons recorded in unlesioned animals, 2) 14 neurons recorded after forebrain hemisection, 3) 12 neurons recorded after partial forebrain hemisection that reproduced nonspecific effects of the surgical lesion while leaving forebrain connections intact. As predicted, DA neurons recorded after full forebrain hemisection yielded statistically significant reductions in sequential predictability relative to control neurons and neurons recorded following partial hemisection. These data support the hypothesis that the sequence-dependent behavior of DA neurons arise in part from interactions with forebrain structures. ISI sequences recorded from unlesioned rats demonstrated maximum predictability when an average of 3.7 prior events were incorporated into the forecasting algorithm, thereby suggesting a physiological process whose "depth" of history-dependence is approximately 600-800 msec. Additional studies examining the functional significance of sequence-dependent ISI structure exhibited by nigral DA neurons are indicated.


Assuntos
Potenciais de Ação/fisiologia , Dopamina/metabolismo , Neurônios/metabolismo , Substância Negra/metabolismo , Algoritmos , Animais , Denervação/efeitos adversos , Masculino , Modelos Neurológicos , Vias Neurais/citologia , Vias Neurais/metabolismo , Vias Neurais/cirurgia , Neurônios/citologia , Valor Preditivo dos Testes , Prosencéfalo/citologia , Prosencéfalo/metabolismo , Prosencéfalo/cirurgia , Ratos , Ratos Sprague-Dawley , Substância Negra/citologia , Fatores de Tempo
16.
Synapse ; 39(4): 313-8, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11169781

RESUMO

Ifenprodil is known to inhibit channel opening of NMDA receptors containing the NR2B subunit. However, it has also been shown to increase NMDA receptor affinity for glutamate-site agonists, including NMDA. The coexistence of the two opposing effects may explain why ifenprodil can either enhance or suppress an NMDA response depending on the level of NMDA binding and thus the NMDA concentration. Using whole cell recordings in rat prefrontal cortical slices, we report here that the effect of ifenprodil also depends on the speed and the direction of change of NMDA concentration. As shown previously, ifenprodil increased the inward current induced by low concentrations of NMDA applied through a local Y-tube perfusion system. However, the rising phase of the current was less enhanced compared to the falling phase. Increasing the speed of rising of NMDA concentration further reduced the enhancing effect of ifenprodil. When pressure ejection was used to produce even faster NMDA responses, the entire rising phase including the peak of the response was suppressed by ifenprodil, while the falling phase remained enhanced. These results are consistent with the suggestion that ifenprodil decreases both the association and dissociation rates of NMDA from NMDA receptors, and suggest that ifenprodil affects slow and fast NMDA responses in different manners. In particular, this study suggests that ifenprodil inhibits the rising phase of a fast NMDA response by suppressing both channel opening and the association of NMDA with NMDA receptors and that this inhibition can occur even when the level of NMDA binding is low.


Assuntos
Agonistas de Aminoácidos Excitatórios , Antagonistas de Aminoácidos Excitatórios/farmacologia , N-Metilaspartato/antagonistas & inibidores , Piperidinas/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Animais , Condutividade Elétrica , Agonistas de Aminoácidos Excitatórios/administração & dosagem , Agonistas de Aminoácidos Excitatórios/farmacologia , Cinética , Masculino , N-Metilaspartato/administração & dosagem , N-Metilaspartato/farmacologia , Perfusão , Córtex Pré-Frontal/fisiologia , Ratos , Ratos Sprague-Dawley
17.
Synapse ; 37(1): 56-63, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10842351

RESUMO

Ifenprodil has been widely used as an antagonist selective for NMDA receptors containing the NR2B subunit. Evidence suggests, however, that ifenprodil also increases NMDA receptor affinity. Using rat brain slices, we found that ifenprodil enhanced NMDA-induced current in both cortical and subcortical areas examined. To test whether the effect is due to an increase in NMDA receptor affinity, we compared the effect of ifenprodil on currents induced by different concentrations of NMDA. Consistent with the hypothesis, the enhancing effect (percent increase) was relatively constant at low NMDA concentrations. As NMDA concentration increased, however, the effect decreased. To test whether the effect is blocked when NMDA binding sites are saturated with NMDA, high concentrations of NMDA were applied. To partially block Ca(2+) influx and prevent cells from deteriorating, the experiments were performed in the presence of either MK801 or kynurenate, two noncompetitive antagonists. Under such conditions, ifenprodil not only failed to potentiate NMDA currents, but consistently suppressed the current. When the same concentration of NMDA was applied in the presence of the competitive antagonist CGP37849, ifenprodil regained its ability to potentiate NMDA currents. Furthermore, the higher the concentration of CGP37849 the more the NMDA current was potentiated by ifenprodil. These results, combined with previous studies, suggest that the enhancing effect is due to an increase in NMDA receptor affinity and is specific for responses induced by low NMDA concentrations. As NMDA concentration increases, the affinity-enhancing effect decreases. Consequently, the channel-suppressing effect becomes more prominent.


Assuntos
Antagonistas de Aminoácidos Excitatórios/farmacologia , Piperidinas/farmacologia , Células Piramidais/fisiologia , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/fisiologia , 2-Amino-5-fosfonovalerato/análogos & derivados , 2-Amino-5-fosfonovalerato/farmacologia , Animais , Maleato de Dizocilpina/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Eletrofisiologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Glicina/farmacologia , Ácido Cinurênico/farmacologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , N-Metilaspartato/farmacologia , Técnicas de Cultura de Órgãos , Córtex Pré-Frontal/química , Córtex Pré-Frontal/citologia , Córtex Pré-Frontal/fisiologia , Células Piramidais/química , Ratos , Ratos Sprague-Dawley , Espermina/farmacologia
18.
J Neurosci ; 20(9): 3504-11, 2000 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10777813

RESUMO

By increasing dopamine (DA) release and activating feedback mechanisms, amphetamine and related psychostimulants are known to inhibit DA cell firing. Here, we report that D-amphetamine also has an excitatory effect on DA cells, which under control conditions, is masked by the inhibitory effect of D-amphetamine and is revealed when D2-like receptors are blocked. Thus, using in vivo single-unit recording in rats, we found that the selective D2 antagonist raclopride not only blocked the inhibition induced by D-amphetamine but also enabled D-amphetamine to excite DA cells. The excitation, expressed as an increase in both firing rate and bursting, persisted when both D1- and D2-like receptors were blocked by SCH23390 and eticlopride, suggesting that it is not mediated by DA receptors. The norepinephrine uptake blocker nisoxetine mimicked the effect of D-amphetamine, especially the increase in bursting, whereas the 5-HT uptake blocker fluoxetine produced no significant effect. Adrenergic alpha1 antagonists prazosin and WB4101 and the nonselective alpha antagonist phenoxybenzamine completely blocked increase in bursting induced by D-amphetamine and partially blocked the increase in firing rate. The alpha2 antagonist idazoxan and the beta antagonist propranolole, however, failed to prevent D-amphetamine from producing the excitation. Thus, revising the traditional concept, this study suggests that D-amphetamine has two effects on DA cells, a DA-mediated inhibition and a non-DA-mediated excitation. The latter is mediated in part through adrenergic alpha1 receptors.


Assuntos
Dextroanfetamina/farmacologia , Dopaminérgicos/farmacologia , Neurônios/efeitos dos fármacos , Receptores Adrenérgicos alfa/efeitos dos fármacos , Receptores Dopaminérgicos/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Antagonistas Adrenérgicos alfa/farmacologia , Animais , Antagonistas de Dopamina/farmacologia , Masculino , Neurônios/fisiologia , Racloprida/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Adrenérgicos alfa/fisiologia , Receptores Dopaminérgicos/fisiologia , Substância Negra/efeitos dos fármacos , Substância Negra/fisiologia , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/fisiologia
19.
Zhongguo Yi Liao Qi Xie Za Zhi ; 24(2): 82-5, 2000 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-12583094

RESUMO

This paper presents to you the principles, composition and features of the multifunctional molecular electrophoretograms processing system.


Assuntos
Sistemas Computacionais , Eletroforese/instrumentação , Processamento de Imagem Assistida por Computador/instrumentação , Eletroforese/métodos , Biologia Molecular , Albumina Sérica/análise , Processamento de Sinais Assistido por Computador , Software
20.
Synapse ; 35(2): 111-9, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10611636

RESUMO

To investigate the role of D(1)-like receptors in endogenous dopamine (DA)-mediated feedback control of DA neurons in vivo, single unit recordings were made from rat nigral DA cells using low cerveau isolé preparations. The D(2) antagonist raclopride, but not the D(1) antagonist SCH23390, increased baseline activity of DA neurons, suggesting that spontaneously released DA acts primarily through D(2)-like receptors to inhibit DA cells. However, feedback inhibition induced by an increased DA release by D-amphetamine (1 mg/kg, i.v.) was partially reversed by SCH23390. The same inhibition, on the other hand, was always completely reversed by raclopride, suggesting that the D(1)-mediated portion of the inhibition depends upon co-activation of D(2)-like receptors. In rats with forebrain hemitransections, D-amphetamine-induced inhibition was markedly decreased and the remaining inhibition was not blocked by SCH23390, supporting the suggestion that D(1)-D(2) co-activation-induced inhibition is mediated through long feedback pathways. In chloral hydrate-anesthetized rats, D-amphetamine-induced inhibition was also insensitive to SCH23390; however, the degree of the inhibition was not reduced. Combined with previous studies, these data suggest that chloral hydrate not only inactivates the D(1) feedback pathway but also enables the D(2) feedback pathway to operate independently of D(1)-like receptors. Conversely, in parkinsonian animals D(1) receptor activation alone has been reported to inhibit DA cells. Taken together, these results suggest that a major portion of endogenous DA-mediated feedback inhibition is due to concurrent activation of D(1)- and D(2)-like receptors. However, this D(1)-D(2) interdependence may alter under certain conditions and may play a role in the pathophysiology of Parkinson's disease.


Assuntos
Benzazepinas/farmacologia , Dopamina/metabolismo , Neurônios/fisiologia , Prosencéfalo/fisiologia , Racloprida/farmacologia , Receptores de Dopamina D1/fisiologia , Receptores de Dopamina D2/fisiologia , Substância Negra/fisiologia , Animais , Dextroanfetamina/farmacologia , Antagonistas de Dopamina/farmacologia , Retroalimentação , Técnicas In Vitro , Masculino , Neurônios/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D1/efeitos dos fármacos , Receptores de Dopamina D2/efeitos dos fármacos , Substância Negra/efeitos dos fármacos
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