Increased expression of the NF2 tumor suppressor gene product, merlin, impairs cell motility, adhesionand spreading

The neurofibromatosis 2 ( NF2 ) gene product, merlin, is a tumor suppressor protein mutated in schwanno-mas and several other tumors. Merlin, which shares significant homology with the actin-associated proteins ezrin, radixin and moesin (ERM proteins), inhibits cell growth when overexpressed in cell lines. The similarities between merlin and ERM proteins suggest that merlin's growth-regulatory capabilities may be due to alterations in cytoskeletal function. We examined this possibility in rat schwannoma cell lines overexpressing wild-type merlin isoforms and mutant merlin proteins. We found that overexpression of wild-type merlin resulted in transient alterations in F-actin organization, cell spreading and cell attachment. Merlin overexpression also impaired cell motility as measured in an in vitro motility assay. These effects were only observed in cells overexpressing a merlin isoform capable of inhibiting cell growth and not with mutant merlin molecules (NF2 patient mutations) or a merlin splice variant (isoform II) lacking growth-inhibitory activity. These data indicate that merlin may function to maintain normal cytoskeletal organization, and suggest that merlin's influence on cell growth depends on specific cytoskeletal rearrangements.      

由重组腺相关病毒1／2载体携带的LacZ报告基因在脐血间质干细胞中的表达

目的:观察由重组腺相关病毒1/2载体携带的LacZ报告基因在体外培养的脐血间质干细胞中的表达情况。方法:实验于2005-10/2006-02在上海交通大学附属新华医院科研中心完成。①以孕龄近60d的杂种妊娠犬的脐带血作为实验用脐血间质干细胞的标本来源。重组腺相关病毒1/2载体-lacZ基因(北京本原正阳基因技术有限公司)。②无菌条件下采集妊娠犬脐带血,置于预装有肝素的离心管中,与Hanks液1∶1混合均匀,叠加于相对密度为1.077的淋巴细胞分离液上,梯度离心分离后进行培养和扩增。③取第4代脐血间质干细胞,经胰酶消化后吹打成单细胞悬液,以5×104/孔接种于24孔板内,随机数字表法分为转染组20孔、空白对照组4孔。转染组将重组腺相关病毒1/2载体-lacZ报告基因(1×1012v.g.mL-1)用不含血清的IMDM培养液作系列滴度稀释,分为5个滴度,即感染复数分别为每个细胞1×102,1×103,1×104,1×105,1×106v.g,各感染复数均设4孔;空白对照组未加入病毒,只加入相同体积的不含血清的IMDM培养液。④转染72h后采用X-gal化学染色法进行检测,成功转染上LacZ基因的脐血间质干细胞其胞浆内会因合成半乳糖苷酶而呈阳性蓝染。每组样本随机选取5个视野,相差显微镜下计数半乳糖苷酶阳性细胞数,取均值即为LacZ基因细胞转染率。结果:①脐血间质干细胞生长情况及LacZ报告基因表达的检测:转染组病毒基因转染后未再见到明显的细胞增殖,转染72h后大部分细胞表达LacZ基因并合成半乳糖苷酶,X-gal染色呈蓝色,长梭形;4～6周后细胞形态趋向老化,长梭形逐渐变为宽扁形;8周后细胞均被蓝染,颜色明显较转染72h时深,细胞形态由长梭形变为不规则,明显老化。空白对照组细胞反应均为阴性。②LacZ报告基因细胞转染率测定结果:转染72h后,感染复数为每个细胞1×102v.g时,仅有少数细胞蓝染呈阳性;感染复数为每个细胞1×103,1×104,1×105,1×106v.g时,转染率分别为(43±5)%,(82±4)%,(95±4)%,(97±3)%。结论:体外培养的脐血间质干细胞能高效转染重组腺相关病毒1/2载体-lacZ报告基因,在一定感染复数范围内,细胞转染率随着感染复数的增加而升高。提示脐血间质干细胞是重组腺相关病毒1/2载体-lacZ报告基因转染的适宜靶细胞。     

高效液相色谱法测定人血清及尿中奥拉西坦的浓度

以阿昔洛韦(acyclovir)为内标,NH2柱为分析柱;乙腈:水(80:20,v/v)为流动相,检测波长为210nm,建立了测定人血清及尿中奥拉西坦(oxiracetam)浓度的HPLC方法。奥拉西坦和内标保留时间分别为6.3min和8.1min;二峰分离良好。本法平均回收率:血清99.7±5.9%;尿99.0±5.6%,日内及日间相对标准偏差(RSD)为5.0～10.9%,血清及尿标准曲线相关良好,最低检测浓度血清为1μg·mL^-1,尿为20μg·mL^-1。本方法操作简便,迅速,灵敏,可靠。可以满足临床药代动力学测试的要求。     

Alopecia in association with severe seborrhoeic dermatitis following combination antiretroviral therapy for acute retroviral syndrome

We present a case where alopecia occurred with severe seborrhoeic dermatitis associated with the commencement of combination antiretroviral therapy for acute retroviral syndrome. We postulate that the eruption could represent a novel manifestation in association with immunological response to antiretroviral therapy.     

Neuroanatomical and neuropharmacological study of opioid pathways in the mesencephalic tectum: effect of mu(1)- and kappa-opioid receptor blockade on escape behavior induced by electrical stimulation of the inferior colliculus

Deep layers of the superior colliculus (DLSC), the dorsal and ventral periaqueductal gray matter (PAG), and inferior colliculus (IC) are midbrain structures involved in the generation of defensive behavior. beta-Endorphin and Leu-enkephalin are some neurotransmitters that may modulate such behavior in mammals. Light microscopy immunocytochemistry with streptavidin method was used for the localization of the putative cells of defensive behavior with antibodies for endogenous opioids in rat brainstem. Midbrain structures showed positive neurons to beta-endorphin and Leu-enkephalin in similar distributions in the experimental animals, but we also noted the presence of varicose fibers positive to endogenous opioids in the PAG. Neuroanatomical techniques showed varicose fibers from the central nucleus of the inferior colliculus to ventral aspects of the PAG, at more caudal levels. Naloxonazine and nor-binaltorphimine, competitive antagonists that block mu(1)- and kappa-opioid receptors, were then used in the present work to investigate the involvement of opioid peptide neural system in the control of the fear-induced reactions evoked by electrical stimulation of the neural substrates of the inferior colliculus. The fear-like responses were measured by electrical stimulation of the central nucleus of the inferior colliculus, eliciting the escape behavior, which is characterized by vigorous running and jumping. Central administration of opioid antagonists (2.5 microg/0.2 microl and 5.0 microg/0.2 microl) was performed in non-anesthetized animals (Rattus norvegicus), and the behavioral manifestations of fear were registered after 10 min, 2 h, and 24 h of the pretreatment. Naloxonazine caused an increase of the defensive threshold, as compared to control, suggesting an antiaversive effect of the antagonism on mu(1)-opioid receptor. This finding was corroborated with central administration of nor-binaltorphimine, which also induced a decrease of the fear-like responses evoked by electrical stimulation of the inferior colliculus, since the threshold of the escape behavior was increased 2 and 24 h after the blockade of kappa-opioid receptor. These results indicate that endogenous opioids may be involved in the modulation of fear in the central nucleus of the inferior colliculus. Although the acute treatment (after 10 min) of both naloxonazine and nor-binaltorphimine causes nonspecific effect on opioid receptors, we must consider the involvement of mu(1)- and kappa-opioid receptors in the antiaversive influence of the opioidergic interneurons in the dorsal mesencephalon, at caudal level, after chronic (2-24 h) treatment of these opioid antagonists. The neuroanatomical study of the connections between the central nucleus of the inferior colliculus and the periaqueductal gray matter showed neuronal fibers with varicosities and with terminal bottons, both in the pericentral nucleus of the inferior colliculus and in ventral and dorsal parts of caudal aspects of the periaqueductal gray matter.