Effect of aging on neuroglobin expression in rodent brain

Neuroglobin (Ngb), a recently discovered O2-binding heme protein related to hemoglobin and myoglobin, protects neurons from hypoxic-ischemic injury in vitro and in vivo. In immunostained mouse brain sections, we found widespread expression of Ngb protein in neurons, but not astrocytes, of several brain regions that are prominently involved in age-related neurodegenerative disorders. Western blots from young adult (3 month), middle-aged (12 month), and aged (24 month) rats showed an age-related decline in Ngb expression in cerebral neocortex, hippocampus, caudate-putamen, and cerebellum. Loss of this neuroprotective protein may have a role in increasing susceptibility to age-related neurological disorders.     

Combined use of positive and negative immunomagnetic isolation followed by real-time RT-PCR for detection of the circulating tumor cells in patients with colorectal cancers

To establish a novel molecular diagnostic method of detecting circulating tumor cells (CTCs) LS174T colon cancer cells were serially diluted with normal blood. Additional peripheral blood samples were collected from 25 patients with colorectal carcinoma. Mononuclear cells (MNCs) were collected, equally divided into four parts, and then cancer cells were enriched by four methods: method A, nonimmunobead method; method B, negative immunobead method: CD45 immunomagnetic beads were used to deplete the leukocytes; method C, positive immunobead method: Ber-EP4 immunomagnetic beads were used to enrich cancer cells; method D, negative-and-positive immunobead method: CD45 immunomagnetic beads were first used to deplete the leukocytes from MNC and then Ber-EP4 immunomagnetic beads were used to enrich cancer cells. Finally, real-time quantitative RT-PCR was used to monitor mRNA expression of ₂-mircoglobulin (2M) and carcinoembryonic antigen (CEA). The relative CEA mRNA values were corrected with reference to 2M mRNA, to CEA mRNA/2M mRNA ratios according to a CEA mRNA external standards prepared with tenfold serial dilutions (1–10⁴ IS174T cells) of cDNA and 2M mRNA external standards prepared with tenfold serial dilutions (10²–10⁷ leukocytes) of cDNA. In recovery experiments a significant correlation between the number of cancer cells and CEA mRNA expression was found when CD45 or Ber-EP4 immunomagnetic beads were used alone. A highly significant correlation was found when CD45 and Ber-EP4 immunomagnetic beads were used successively. The sensitivity of method D was one cancer cell per milliliter of blood. Circulating cancer cells were detected in 19 of 25 patients with colorectal cancers. The relative CEA mRNA value obtained by method D was the smallest. The positive detection rate of circulating cancer cells in patients at Dukes B, C, and D stages were 25.0% (1/4), 83.3% (10/12), and 88.9% (8/9). Combinative use of immunomagnetic isolation followed by real-time RT-PCR is a useful technique to detect circulating tumor cells in patients with colorectal carcinomas. Applying negative and positive immunomagnetic beads successively yields the highest correlation with amount of tumor cells.     

Electrophysiological neurodifferentiation of subventricular zone-derived precursor cells following stroke

Stroke in rodents is associated with increased neurogenesis and the migration of newborn neurons to sites of brain ischemia, where they may participate in repair and recovery. To determine if neurogenesis following stroke yields functional new neurons, we labeled neuronal precursors in the mouse subventricular zone (SVZ) with a lentivirus-green fluorescent protein vector, produced stroke by occluding the middle cerebral artery, and detected newborn neurons 8 weeks later by fluorescence microscopy. Patch-clamp studies on fluorescent neurons in the cortical region surrounding infarction showed tetrodotoxin-sensitive Na⁺ action potentials and spontaneous excitatory post-synaptic currents, suggesting that ischemia led to functional neurogenesis with synaptic integration. These findings support the hypothesis that enhancing endogenous neurogenesis after stroke might have therapeutic benefit.     

糖皮质激素代谢酶11β-羟基类固醇脱氢酶Ⅰ型在新生大鼠脑内的分布与表达

目的　观察新生大鼠脑发育成熟过程中糖皮质激素代谢酶 11β 羟基类固醇脱氢酶Ⅰ型 (11β HSD1)的变化。　方法　免疫组织化学和Western印迹杂交的方法。　结果　免疫组织化学染色表明 ,11β HSD1分布于新生大鼠大脑皮层的各个层次 ,但以Ⅱ层 (外颗粒层 )含量为最高、Ⅲ (锥体细胞层 )、Ⅳ (内颗粒层 )层 11β HSD1的含量次之。海马的各个区域和齿状回也均有 11β HSD1的分布。Western印迹杂交分析表明 ,新生鼠顶叶皮层、海马和下丘脑 11β HSD1的表达在出生后 2周内表达一直比较高 ,第 15d时其表达开始下降。　结论　提示新生鼠大脑 11β HSD1的表达可能与糖皮质激素促进脑组织的发育和成熟有关。     

升压治疗急性脑缺血再灌注损伤保护作用的实验研究

目的:探讨升压治疗局灶性脑缺血的保护作用及治疗的维持时间。方法:采用大鼠局灶性脑缺血再灌注模型,40只大鼠随机分为五组:模型对照组(A)、升压维持15min组(B)、维持45min组(C)、维持90min组(D)和120min组(E),观察各组神经功能评分、脑梗死体积和病理学改变。结果:神经功能缺损评分B、C、D组明显低于A组;B、C、D、E各组脑梗死体积明显低于A组,C、D、E组明显低于B组;各治疗组组织病理学改变比对照组轻,B组最轻。结论:缺血3h再灌注时,升压维持时间在2h以内对脑损伤有保护作用,升压最佳维持时间是15min。     

急性白血病bcl-2表达及与耐药的关系

t(14;18)染色体易位产生融合基因bcl-2/IgH,bcl-2高表达可阻抑细胞凋亡的发生,bax可拮抗bcl-2的抗凋亡效应,起着加速细胞凋亡的作用.bcl-2和bax基因的紊乱是AL(急性白血病)形成与发展的原因之一.这些细胞凋亡调控基因不仅参与了白血病的形成,还与白血病的某些临床特征、疗效及预后因素密切相关.在治疗bcl-2相关肿瘤时,若能联合使用bcl-2反义核酸和其它诱导细胞死亡制剂,可使肿瘤细胞对后者的敏感性增加,从而提高治疗效果.