A via L-arginina-óxido nítrico no transtorno depressivo e sua associação com a função plaquetária e o estresse oxidativo

O transtorno depressivo (TD) é um fator de risco cardiovascular independente que apresenta elevada morbi-mortalidade. Recentes evidências sugerem a participação do óxido nítrico (NO), potente vasodilatador e anti-agregante plaquetário, na patogênese de doenças cardiovasculares e psiquiátricas. A síntese do NO ocorre através da conversão do aminoácido L-arginina em L-citrulina e NO, pela ação da enzima NO sintase (NOS). Esta tese aborda o papel da via L-arginina-NO em plaquetas de pacientes com TD e sua associação com a função plaquetária e estresse oxidativo. Para análise comportamental da depressão em modelo animal, foi utilizado o modelo de estresse pós-natal de separação única (SMU). Os animais foram divididos em quatro grupos para a realização do estudo: Grupo Controle Sedentário (GCS), Grupo Controle Exercício (GCE), Grupo SMU Sedentário (SMUS) e Grupo SMU Exercício (SMUE). O treinamento físico (TF) dos animais englobou 8 semanas, com duração de 30 minutos e uma velocidade de treinamento estabelecida pelo teste máximo (TE). Para o estudo em humanos, 10 pacientes com TD com score Hamilton: 201, (média de idade: 384anos), foram pareados com 10 indivíduos saudáveis (média de idade: 383anos). Os estudos em humanos e animais foram aprovados pelos Comitês de Ética: 1436 - CEP/HUPE e CEUA/047/2010, respectivamente. Foi mensurado em humanos e em animais: transporte de L-arginina, concentração GMPc, atividade das enzimas NOS e superóxido dismutase (SOD) em plaquetas e cortisol sistêmico. Experimentos realizados somente em humanos: expressão das enzimas NOS, arginase e guanilato ciclase através de Western Blotting. A agregação plaquetária foi induzida por colágeno e foi realizada análise sistêmica de proteína C-reativa, fibrinogênio e L-arginina. Para o tratamento estatístico utilizou-se três testes estatísticos para avaliar as diferenças das curvas de sobrevida: Kaplan-Meier, e os testes de Tarone-Ware e Peto-Prentice. Em humanos, houve uma redução do transporte de L-arginina, da atividade das enzimas NOS e SOD, e da concentração de GMPc em plaquetas, e nas concentrações plasmáticas de L-arginina no grupo com TD em relação ao grupo controle. Foi observado um aumento dos níveis plasmáticos de fibrinogênio no TD. Esses resultados demonstram uma inibição da via L-arginina-NO-GMPc e da enzima anti-oxidante SOD em pacientes com TD sem afetar a função plaquetária. Em relação ao TF, para o modelo animal, foram encontradas alterações iniciais quanto à distância percorrida e tempo de execução do TE entre os grupos controles e o grupos SMUs, apresentando estes últimos menores valores para o TE. Após 8 semanas de TF, verificou-se um maior influxo no transporte de L-arginina para o SMUE em comparação ao grupo SMUS. As diferenças observadas para o tempo e a distância percorrida no TE inicial entre os grupos controle e no modelo de estresse foram revertidas após as 8 semanas de TF, demonstrando o efeito benéfico do exercício físico na capacidade cardiorespiratória em modelos de depressão.

532 nm激光泵浦硝酸钡晶体产生外腔拉曼激光

由于硝酸钡晶体具有很强的对称振动（频率1047 cm^-1）和较高的拉曼增益,可以用来产生受激拉曼激光.采用单端泵浦的外置拉曼振荡腔与双棱镜分光装置进行了硝酸钡晶体拉曼激光实验,泵浦源为倍频Nd： YAG的532 nm激光,硝酸钡晶体通过水溶液降温法生长,尺寸为10 mm×10 mm×48 mm,采用特殊镀膜的腔镜对各阶斯托克斯光进行优化选择.在泵浦源达到65 mJ时,获得21 mJ一阶斯托克斯光,输出波长为563 nm,以及16 mJ的二阶斯托克斯光,输出波长为599 nm,受激拉曼散射SRS最大的整体

Avaliação da presença de metilparabeno e propilparabeno no ambiente aquático e seus potenciais estrogênicos e a toxicidade aguda.

Atualmente no cenário mundial a qualidade da água tem gerado muitas preocupações, pois milhares de produtos sintéticos são produzidos para facilitar muitas práticas industriais, domésticas e pessoais e com isso diversas substâncias químicas utilizadas para esses fins são introduzidas no meio ambiente. Os parabenos são substâncias químicas utilizadas pelas indústrias farmacêuticas, de alimentos e cosméticos e que cuja função é a conservação, sendo que há muitos questionamentos em relação a sua segurança, pois alguns relatórios têm mostrado que a exposição a esses parabenos pode modular ou perturbar o sistema endócrino e com isso gerar consequências prejudiciais à saúde humana e aos ambientes aquáticos. Esse estudo teve como objetivo avaliar a presença dos Parabenos Metilparabeno e Propilparabeno no ambiente aquático e os seus potenciais estrogênicos e a toxicidade aguda. A metodologia se desenvolveu a partir do ensaio in vitro YES para a determinação da atividade estrogênica, ensaios de toxicidade aguda em Daphnia similis e em Aliivibrio fischeri e a quantificação dos parabenos na água do Rio Maracanã-RJ através da cromatografia líquida acoplada ao espectrômetro de massa. Os resultados obtidos para a CE50 dos MP e PP, a partir do ensaio in vitro YES, foi de 18,91 mgL-1 e 7 mgL-1 e a magnitude da resposta foi de 10-5 e 10-4 menos potente que 17ß-estradiol para o MP e o PP, respectivamente. A partir do ensaio de toxicidade aguda, os valores de CE50 obtidos em Daphnia similis, foi de 29,42 mgL-1 e 9,94 mgL-1e em Aliivibrio fischeri foi de 3,047 mgL-1 e 1,946 mgL-1, respectivamente, com isso observou-se que o PP é mais tóxicos em todos os organismos testados, sendo mais tóxicos para um e menos para outros. A água do Rio Maracanã não foi tóxica para a Daphnia similis em nenhum dos dois pontos, já para o Aliivibrio fischeri foi tóxica em apenas um ponto. As concentrações encontradas de MP e PP foram maiores no ponto onde, de acordo com os parâmetros físico-químicos, a qualidade da água não está dentro dos padrões exigidos pela legislação, sendo quantificados na ordem de ngL-1, contudo é válido ressaltar que os DEs não são encontrados no meio ambiente separados, eles interagem entre si e provocam efeitos aditivos ou sinérgicos, sendo muito difícil de prever qual o efeito, por isso é importante o conhecimento do potencial estrogênico das substâncias simples, pois em um estudo com uma matriz ambiental, pode-se observar se houve algum efeito aditivo ou sinérgico de outras substâncias.

National report of the frame survey 2006 in the Ugandan part of Lake Victoria

Fisheries Frame surveys have been carried out on Lake Victoria biannually since 2000 to determine· the number of fishers, fish landing sites, facilities at the landing sites. Information on the composition fishing crafts, their mode of propulsion, fishing gears and the fish species they target is also collected. This information is used to guide development and management of the lake's fisheries. The results of the four surveys carried out since 2000 show that the number of landing sites has decreased by 24% from 597 in 2000 to 481 in 2006, mainly as result of reorganisation of landing sites into Beach Management Units (BMUs). The fish landing sites continue to have inadequate facilities to service the fisheries industry e.g. in the 2006 survey only 11.2% of landing sites had fish shades; <0.6% had cold rooms; 3.5% had electricity; and only 35.5% had toilet facilities. Similarly, only 11.4% of landing sites had portable water; 2.5% had jetties, 3.7% had 'fish stores; and 36% were accessible by all weather roads. There is need to improve facilities servicing fisheries at landing sites, with major emphasis on sanitary facilities, especially toilets and portable water. The BMUs should be sensitised to prioritise the construction and utilisation of public toilet facilities at their respective landing sites. The ultimate aim should be to have public toilets at all fish landing sites. The trend of the various indicators of fishing effort has continued upwards: The total number of fishers increased by 43.5% from 37,721 in 2004 to 54,148 in 2006 and the number of fishing crafts increased (43.9%) from 16,775 in 2004 to 24,148 in 2006 over the same period. The total number of gillnets increased by 28.6% from 458,597 in 2004 to 589,777 in 2006 and the number of long line hooks increased by 136% from 968,848 to 2,285,609. The number of fishing crafts using outboard engines also increased from 3,173 in 2004 to 5,047 in 2006 suggesting that more fishers were going far in search of fish. There is still a large number of illegal gears especially beach seines, which increased by 58.8% from 954 in 2004 to 1420 in 2006. Efforts to remove these very destructive gears should be stepped up. There was also larger increase in number of illegal gillnets <5 inch mesh size. These increased by 63% from 56,246 in 2004 to 91,740 in 2006 compared with 23.8% increase of gillnets ~5 inch mesh size. There were also large increases in the numbers of gillnets of 5 and 5% inch mesh size, which increased by 48% and 130% from 2004 to 2006 implying a trend towards use of smaller gillnet mesh sizes. The number of traps which are used in shallow vegetated areas, flood plains and river mouths to target tilapiines and riverine species decreased drastically from 5,361 traps in 2004 to only 499 traps in 2006, a decrease of 974%, a phenomenon attributed to the receding water levels which have left the shallow vegetated areas dry. A total of 17,475 fishing crafts, 72% of all fishing crafts, in the Ugandan part of the lake are still using paddles and the. number of parachute crafts is also still very high, (Le. 5,064) comprising a high proportion (21 %) of the total number of fishing. There is need to promote the use of large fishing crafts with sails or a combination of sail and outboard motor. The Mukene fishery in the Ugandan waters of Lake Victoria has remained underdeveloped with only 9% of all fishing crafts operating in this fishery. Also less than 2% of fishing crafts with sails or motor operate in this fishery which implies that it is limited to near shore waters. Effort should be made to develop this fishery as it appears to have high potential, especially in deep offshore waters which are hardly fished.

中国部分猪种SLA2DQB 外显子2 遗传多样性

运用PCR2SSCP 和克隆测序对中国部分猪种的SLA2DQB 基因外显子2 的多态性分析表明:有功能的 DQB 基因有68 个新等位基因,假基因(SLA2DXB) 等位基因有5 个。各等位基因的数量分布极其不平衡,而且许多 品种都表现出共享等位基因。9 个主要等位基因中, C08 广泛分布在中国猪种的6 大地方类型11 个品种及云南 和四川野猪中,它为中国猪种特有的共享等位基因,占总数的55. 10 %。在单一的个体中拥有5 条以上序列,说明 SLA2DQB 基因座在某些品种中拷贝数为3 个。SLA2DQB 外显子2 的等位基因核苷酸和氨基酸多态变异位点分别 高达81 个和49 个,等位基因多样度( H= 0. 889) 以及核苷酸多样度( Pi = 0. 047) 都很高,总体表现为β折叠区的Pi 值均高于α螺旋区。综合分析表明华南型、西南型猪H和Pi 均较高,高原型的藏猪最低。类群内遗传距离排序与 Pi 值高低排序一样,可见各地方类型中核苷酸替换的差异正比于核苷酸多样度。类群间遗传距离比较,江海型与 华北型间的距离最大,而华中型和高原型间的遗传距离最小。

The study of biological characteristic and population dynamic of Caspian vimba (Vimba vimba persa), in coastal waters of Caspian Sea (Mazandaran Province)

This study was conducted to determine reproduction characteristics, diet regime, age structure and population dynamics parameters of the vimba vimba persa (Pallas, 1811) in Mazandaran waters of the Caspian Sea, from October 2008 to September 2009. A total of 994 specimens were monthly collected by beach seine and cast net from six fish landings of Ramsar, Tonekabon, Chaloos, Mahmood Abad, Sari and Behshahr. Biometric characters were measured for each specimen at the laboratory. Scales were used for age determination. Sex determination and fecundity were determined. Population dynamic parameters as well as stock assessment including cohort analysis were estimated using FISAT software. The finding showed that the mean of fork length and body weight of the Caspian Vimba were 168.4±2.6 mm and 71.94±32.24 g respectively. Strong correlation was found between these two variables (a= 0.012; b = 3.047; r2 = 0.955). 92 specimens were studied from the fecundity point of view. This species was found to have more abundance in spring (esp. Apr-May). The samples composed of 397(42.6%) male, 537(57.4%) female; Overall sex ratio (M: F =1: 1.35) was significantly different from the expected 1:1 ratio (p ≤0.05). The advanced stages of maturity (4th & 5th) were found in April and May. The highest Gonadosomatic Index in female was in May and the lowest one was in July. This fish is therefore a spring spawner. The maximum absolute and relative fecundities were 34640 and 260.9, respectively; the minimum absolute and relative fecundities were 5400 and 94.5 respectively. The averages of absolute and relative fecundities were 17198±7710 and 171.85±48.8, respectively. Coefficient vacuity index was 59.2% which indicates that this fish is mesophagous. Among of living creature consumes by Caspian Vimba mollusks, 76 arthropods, worms, plants, detritus and fishes were found 32.9% , 26.7% , 13.4% , 17% , 4.4% and 1.6% respectively. The infinite fork lengths were 261 mm for females, 25mm for males and 261 mm for both sexes respectively. For population growth and mortality parameters; K ( 0.28 per year for both sexes, 0.3 per year for males, 0.33 per year for females); t0 ( -0.65 year for both sexes, -0.23 year in females, -0.51 year in males ); Φ' ( 2.28 ); Z ( 0.98 per year ); M ( 0.59 per year); F ( 0.39 per year) and Exploitation coefficient was 0.4. The analysis showed that total biomass and MSY were 1336 and 528.8 tonnes respectively.

滇池太湖新银鱼的生长特性与资源量关系的研究

经31个月的连续采样调查,应用Von Bertalanffy生长方程,得到太湖新银鱼1989年和1990年生长方程。据此拟合出体重与种群密度关系W=1.047-0.671 1gC,种群密度与资源量关系F=1999.36C e~(-0.2045C),最终演译出资源量平衡点在1847t。相应体重1.0g/尾;密度指标1.175尾/m~(3);捕捞时间在8月。

A report of the fisheries catch assessment survey (CAS) in the Ugandan waters of Lake Victoria for July 2005

This report presents findings of the first CAS in the Ugandan waters following the agreed SOPs, carried out in July 2005. The findings indicate a total fish catch of 15,047.5 t for July 2005, contributed by Mukene/Dagaa (39.5%), Nile perch (33.1%), Tilapias (17.1%), Haplochromines (9.2%) and other fish species 1.2%. This information gives a new perspective of the estimates of fish production in the Ugandan waters of the lake which are based on field observations. Continuation of support to the CAS programme will certainly get rid of the uncertainties about the fish production levels of the lake which have been there for a long time. This information is vital for fisheries development and fisheries management endeavours.

中国急流牙甲族的系统学研究

急流牙甲族Sperchopsini属于鞘翅目Coleoptera牙甲科Hydrophilidae的水牙甲亚科Hydrophilinae，共包括五属，即水龟虫属 Hydrocassis、革牙甲属 Ametor、Sperchopsis、Anticura、Cylomissus，世界共计有25种，我国分布有2属18个种。 本文回顾了水甲虫、牙甲科以及急流牙甲族的研究简史；综述了水甲虫在分类学、保护生物学、形态学、遗传学、分子生物学等方面研究进展，总结了水甲虫与生态因子的关系以及水甲虫作为生态系统健康指示物的可行性。还简要介绍了昆虫分子系统学，以及细胞色素氧化酶亚基I（COI）和rDNA内部转录间隔区（ITS）在昆虫学研究中的应用。 通过对收集到的700余号急流牙甲族的标本观察和分类研究，发现了一新种（内蒙水龟甲Hydrocassis mongolica sp.nov.）。并且对已知全部种类重新作了描述，特别是长茎革牙甲 Ametor elongatus雄性外生殖器部分，首次对7个种类（长茎革牙甲 Ametor elongatus、粗革牙甲 Ametor scabrosus、帝水龟甲 Hydrocassis imperialis、伪舟水龟甲Hydrocassis pesudoscapha、条纹水龟甲Hydrocassis scapulata、舟水龟甲 Hydrocassi scapha、四川水龟甲Hydrocassis sichuana）的雌性个体进行了描述。编制了急流牙甲族的分属、分种检索表。 采用支序分类学的方法对中国急流牙甲族种类的系统发育关系进行探讨。结果显示革牙甲属内的A. latus、A. rudesculptus、A. rugosus 及A. scabrosus 构成单系（不包括A. elongates），支持皱革牙甲A. rugosus和A. latus属于革牙甲属。水龟虫属内H. anhuiensis、H. baoshanensis、H. lacustris、H. pseudoscapha、H. scaphoides、H. scapulata、H. sichuana、H. taiwana、H. uncinata、H. schillhammeri构成一个单系。水龟虫属包括两大类群，一类群包括H. anhuiensis、H. lacustris、H. scapulata、H. sichuana 、H. taiwana，另一类群包括H. baoshanensis、H. scaphoides、 H. schillhammeri 、H. uncinata。两类群的不同之处在于后一类群的阳基侧突上有一齿状凸起。 测序了H. scapulata、H. sichuana和H. mongolica雌雄各一个个体的COI和ITS2序列。全部的COI基因序列为828bp，编码275个氨基酸。H. scapulata的ITS2序列有446bp，H. sichuana的有456bp，H. mongolica的有455bp。用MEGA 3.1计算比对距离（pairwise distances）和构建邻近系统树。结果显示对于COI，种内的比对距离分别是0(H. scapulata)、0.008(H. mongolica)、0.004(H. sichuana)，种间的比对距离在0.024-0.045之间。对于ITS2，种内的比对距离分别为0.005(H. scapulata)、0(H. mongolica)、0.007(H. sichuana)，种间的比对距离在0.028-0.047之间。H. sichuana和新种间的比对距离在0.024-0.037(COI)和0.044(ITS2)。比对距离揭示出种内低于0.008，种间在0.024-1.078之间。因而，它们之间应该是种间关系而不是种内的关系。COI数据集和ITS2数据集所构建的系统树存在一定的差异，前者显示四川水龟甲和条纹水龟甲是姐妹种，后者显示新种和条纹水龟甲是姐妹种。总之，在内蒙古自治区发现的为一新的物种。

激波管壁AlO自由基B~2∑~+-X~2∑~+和C~2∏_r-X~2∑~+带系辐射光谱的研究

爆轰驱动过程中产生的高温高压气流对铝质膜片、激波管壁产生烧蚀和冲刷作用,以致激波管壁、端盖上附有氧化铝等杂质,而高温下AlO自由基在气体分子的高速碰撞下被激发并产生强烈的辐射,从而干扰了高温气体辐射光谱的分析。用爆轰驱动加热技术将空气加热到4 000~7 000 K,利用多通道光学分析仪对AlO自由基辐射光谱进行分析,实验发现在460~530 nm波长范围内有多支辐射非常强烈的AlO自由基B2Σ+-X2Σ+(T00=20 689 cm-1)带系辐射谱带,且每支谱带都由多个带头组成,带头间隔约为2 nm,带头处于高频位置并向低频方向伸延。通过实验与理论计算相结合,重点分析了AlO自由基B2Σ+-X2Σ+带系辐射光谱的结构特征。AlO自由基C2Πr-X2Σ+(T00=33 047 cm-1)带系辐射光谱处于270~335 nm波长范围内,其辐射强度相对于B2Σ+-X2Σ+带系较弱,并且与OH基A2Σ+-X2Π(T00=32 682 cm-1)带系辐射光谱互相干扰而难以分辨,对该波段高温空气的辐射光谱分析产生不利的影响。

Decomposition of emergent macrophyte roots and rhizomes in a northern prairie marsh

Dry mass, nitrogen and phosphorus content in belowground litter of four emergent macrophytes (Typha glauca Godr., Phragmites australis (Cav.) Trin., Scolochloa festucacea (Willd.) Link and Scirpus lacustris L.) were followed for 1.2 years in a series of experimental marshes, Delta Marsh, Manitoba. Litter bags containing roots and rhizome materials of each species were buried in unflooded soil, or soil flooded at three water depths (1–30, 31–60, > 60 cm). There were few differences in dry mass loss in unflooded or flooded soils, and depth of flooding also had little effect on decomposition rates. In the flooded sites, Scolochloa and Phragmites roots lost more mass (48.9–63.8% and 59.2–85.5%, respectively) after 112 days than Typha and Scirpus (36.3–43.6 and 37.0–47.2%, respectively). These differences continued through to the end of the study, except in the shallow sites where Scirpus roots lost more mass and had comparable mass remaining as Scolochloa and Phragmites. In the unflooded sites, there was little difference between species. All litters lost nitrogen (22.9–90.0%) and phosphorus (46.3–92.7%) during the first 112 days, then levels tended to remain constant. Decay rates for our belowground root and rhizome litters were comparable to published literature values for aboveground shoot litter of the same species, except for Phragmites roots and rhizomes which decomposed at a faster rate (−k = 0.0014−0.0032) than shoots (−k = 0.0003−0.0007, [van der Valk, A.G., Rhymer, J.M., Murkin, H.R., 1991. Flooding and the decomposition of litter of four emergent plant species in a prairie wetland. Wetlands 11, 1–16]).

吗啡给药及戒断期间大鼠眶额叶脑区功能活动特征户外环境下自由活动猕猴顶叶及海马神经元单位放电的胞外记录方法

已有的研究表明，眶额叶在解剖上与现在已知的药物滥用相关的脑区是紧密联系在一起的。例如，眶额叶在药物滥用和强迫性重复行为中起作用，且随着脑成像技术的应用，越来越多的证据表明眶额叶参与了药物滥用。但是我们并不了解在阿片给药和戒断期间眶额叶脑区活动是如何变化的。因此，我们在实验中采用了Mn2+增强的核磁共振成像（Manganese-enhanced magnetic resonance　imaging，MEMRI，4.7T）技术和脑电（EEG）记录的方法，以研究大鼠眶额叶在给与阿片类药物（盐酸吗啡）以及戒断过程中的动态变化。 MEMRI是一种近年才发展起来的新型技术。研究表明，Mn2+是Ca2+的类似物，可以通过Ca2+通道进入兴奋性的神经元里面并结合到胞内的蛋白质和核酸上的Ca2+和Mg2+结合位点上 (MILDVAN and COHN, 1963; EISINGER et al., 1965)。另外，Mn2+的顺磁性也为它成为核磁共振成像的造影剂提供了前提条件。可是成功应用MEMRI的前提就是要在适当的时间把合适剂量的Mn2+传递到靶点上。因此，Mn2+在注射到靶点后，是否能够在有效的时间内反映大脑活动的变化就成为一个非常重要并且在技术上较为棘手的问题。在给实验大鼠脑区微量注射Mn2+（80mMol/L，200nl）的同时，通过微量注射兴奋性神经递质谷氨酸（Glu 0.5mM/L）或抑制性递质γ-aminobutyric acid（GABA 0.5M/L）以改变靶点神经元兴奋性的方法，检测Mn2+能否反映脑区的活动变化。另外，我们随机选取实验动物，分别在注射Mn2+ 3小时、5小时和8小时后对三组大鼠（n=5）进行10％福尔马林灌流，并且通过观察大鼠眶额叶脑区Mn2+强度的变化来研究最佳的灌流时间。我们的实验结果表明，Mn2++Glu组的右侧脑区/左侧脑区的Mn2+亮度比Mn2+空白对照组增加了20％（p=0.016, student t-test, *p <0.05），也远大于Mn2++GABA组（p=0.047, *p<0.05）。结果表明，当神经元被兴奋的时候，较多的Mn2+可以通过Ca2+通道进入兴奋的神经元内，使得Mn2+的成像亮度增加。由于Mn2+成像亮度的增加可以反映神经元的兴奋活动，因此可以显示出靶点区的脑活动。另外，在研究灌流时间对Mn2+亮度影响的实验中发现，注射Mn2+ 5小时后灌流得到的信噪比分别比注射Mn2+3小时（p＝0.055）和8小时（p=0.004，*p<0.05）高出24％和32％。总之，我们采用微量注射Mn2+（80mM/L,200nl）后5小时用10%福尔马林心脏灌流的方法获得了较好的结果。另外在试验中我们首先观测了大鼠吗啡戒断后的行为学指标和检测大鼠戒断后条件化位置偏好的程度。实验结果表明大鼠可以建立非常明显的条件化位置偏好，但在湿狗抖等行为学指标上无明显症状。这说明大鼠对于吗啡(10mg/kg, 一天两次，持续12天)形成了明显的心理依赖而无明显的生理依赖。此外，MEMRI的结果表明，在吗啡给药的第1天和第6天，大鼠眶额叶的Mn2+强度与空白对照组相比有显著的降低( one-way ANOVA, Post Hoc Dunnett’s C Tests), F (6,28)=7.242, P<0.001)；而在戒断第3天又恢复到正常水平，在戒断第5天和第7天Mn2+强度跟空白对照组相比没有显著性差别(one-way ANOVA, *p<0.05)。脑电（EEG）的结果表明，急性吗啡诱导的gamma波段的EEG显著降低(Two-way ANOVA, F(1,10)=13.626,p=0.006)。然而在戒断第1天gamma波段的EEG与空白对照组相比是增加的。在戒断第3天和戒断第5天，gamma波段的EEG与空白对照组相比也有显著性增强。以上研究结果表明：大鼠眶额叶脑区的动态变化与整个吗啡给药和戒断过程是密切相关的；此外，MEMRI在探讨药物滥用以及成瘾等机制上有很大的应用前景。

Multi-armed poly(L-glutamic acid)-graft-oligoethylenimine copolymers as efficient nonviral gene delivery vectors

Background The application of polyethylenimine (PEI) in gene delivery has been severely limited by significant cytotoxicity that results from a nondegradable methylene backbone and high cationic charge density. It is therefore necessary to develop novel biodegradable PEI derivates for low-toxic, highly efficient gene delivery.Methods A series of novel cationic copolymers with various charge density were designed and synthesized by grafting different kinds of oligoethylenimine (OEI) onto a determinate multi-armed poly(L-glutamic acid) backbone. The molecular structures of multi-armed poly(L-glutamic acid)-graft-OEI (MP-g-OEI) copolymers were characterized using nuclear magnetic resonance, viscosimetry and gel permeation chromatography. Moreover, the MP-g-OEI/DNA complexes were measured by a gel retardation assay, dynamic light scattering and atomic force microscopy to determine DNA binding ability, particle size, zeta potential, complex formation and shape, respectively. MP-g-OEI copolymers were also evaluated in Chinese hamster ovary and human embryonic kidney-293 cells for their cytotoxicity and transfection efficiency.