大鼠肾脏髓质外皮质组织低氧诱导因子1α在常压模拟高住低练环境中的表达变化

目的:探讨常压模拟高住低练对肾脏髓质外皮质组织低氧诱导因子1α表达的变化。方法:实验于2005-11/2006-07在湖南师范大学体育学院生化实验室、分子实验室及湖南省肿瘤医院分子实验室完成。①实验材料:清洁级8周龄雄性SD大鼠60只,体质量为(200±20)g。②实验分组:60只SD大鼠随机分成两大组:对照组和运动组。其中对照组分为常氧组、高住8h组和高住12h组;运动组分为常氧运动组、高住8h运动组和高住12h运动组,每小组10只。③实验干预:常氧运动组、高住8h运动组、高住12h运动组大鼠每天在坡度为0的动物跑台上以25m/min的速度训练1h。训练完后,将高住8h组、高住8h运动组和高住12h组、高住12h运动组放入体积分数为0.125的低氧(相当于海拔4000m)舱内分别休息8h和12h。训练共4周,5d/周。④实验评估:用免疫组织化学法检测各组大鼠肾脏髓质外皮质组织低氧诱导因子1α表达。结果:60只SD大鼠进入结果分析。低氧诱导因子1α蛋白表达的变化阳性单位值越大,表示低氧诱导因子1α阳性产物蛋白表达越强烈;高住8h组、高住12h组、常氧运动组低氧诱导因子1α蛋白表达值均大于常氧组,差异具有显著性意义(P<0.05);高住8h运动组、高住12h运动组分别与常氧运动组比较,差异均无显著性(P>0.05);高住8h运动组低氧诱导因子1α蛋白表达值明显低于高住12h运动组,差异有显著性意义(P<0.05)。结论:模拟高原环境、高住低练训练均能诱导SD大鼠肾脏低氧诱导因子1α的表达,以低氧12h训练组低氧诱导因子1α的表达最高。     

Comparative analysis of adeno-associated viral vector serotypes 1, 2, 5, 7, and 8 in mouse brain

Recombinant adeno-associated virus serotype 2 (rAAV2) vectors have been shown to deliver genes effectively to neurons in the brain, retina, and spinal cord. The characterization of new AAV serotypes revealed different patterns of transduction in a diverse array of tissues (Gao, G., Vandenberghe, L.H., and Wilson, J.M. [2005]. Curr. Gene Ther. 5, 285-297). Here, we extensively compare the neural tropism of human-derived rAAVs (types 2/1, 2, and 2/5) with nonhuman primate-derived rAAVs (types 2/7 and 2/8) in adult mouse brain. Mice were injected with rAAV type 2/1, 2, 2/5, 2/7, or 2/8 via the caudate-putamen and substantia nigra. Intrahippocampal injections were also performed for rAAV2/7 and rAAV2/8. In all regions injected, the vectors transduced neurons almost exclusively. Retrograde transduction of all rAAV pseudotypes was also observed in particular CNS areas. At high titers, all rAAV pseudotypes transduced comparable brain volumes in all targeted regions except for rAAV2, which transduced much smaller brain volumes. A dose-range comparison of intrastriatally injected rAAV types 2/5, 2/7, and 2/8 highlighted that the transduction efficiency, as determined by transduced volume and biophotonic imaging of green fluorescent protein expression intensity, was significantly higher for rAAV2/5 and rAAV2/7 compared with rAAV2/8 at low titers, whereas all three serotypes performed equally well at higher doses. These results demonstrate the use and efficiency of both human- and nonhuman primate-derived rAAV vectors for disease modeling and their potential for gene therapy.     

Inactivation of Friend erythroleukemia virus and Friend virus- transformed cells by merocyanine 540-mediated photosensitization

The Friend virus complex was used as a model to study the effects of merocyanine 540 (MC 540)-mediated photosensitization on enveloped viruses. Simultaneous exposure to the lipophilic dye MC 540 and white light inactivated cell-free virus, cell-associated virus, and virus- transformed cells. When used under experimental conditions that are known to preserve most mature blood cells, at least some coagulation factors, and a significant portion of the pluripotent hematopoietic stem cell compartment, MC 540-mediated photosensitization reduced virus titers by greater than or equal to 4 log and the concentration of in vitro clonogenic erythroleukemia cells by greater than or equal to 5 log. Animals that received a single intravenous injection of photosensitized virus were resistant to a subsequent challenge with live virus. High sensitivity to MC 540-mediated photosensitization appears to be a property that is shared by other enveloped viruses. Thus, photosensitization mediated by MC 540 may be of benefit in the sterilization of blood products (in particular, cellular products), the production of vaccines, and selected areas of antiviral therapy.     

脐血干细胞转化为肝细胞的研究进展

自进行第1例脐血干细胞移植以来,各国科研机构相继开展对于脐血干细胞的研究,脐血库也纷纷建立．随着再生医学的发展,众多国内外学者在尝试进行非肝源性细胞向肝细胞分化方面的研究,并已经证实脐血干细胞在特定的微环境下可以在体内和体外转化为肝样细胞,为脐血干细胞在肝脏疾病中的应用奠定了基础．本文就脐血干细胞向肝细胞转化的最新研究进展作一综述．     

Toxicity induced by nanoparticles

Nanoparticle research is currently an area of intense scientific interest due to a wide variety of potential applications. Human beings have been exposed to airborne nanosized particles throughout their evolutionary stages, and such exposures have increased dramatically over the last century. Nanoparticle can modify the physicochemical properties of the material as well as create the opportunity for increased uptake and interaction with biological tissues through inhalation, ingestion, and injection. This combination of effects can generate adverse biological effects in living cells. Nanoparticles have proved toxic to human once in the blood stream, nanoparticles, spleen, bone marrow and nervous system can be transported around the body and be taken up by organs tissue and cell cultures, resulting in increased oxidative stress, inflammatory cytokine production and cell death. Unlike larger particles, nanoparticles may be taken up by cell mitochondria and the cell nucleus studies demonstrate the potential for nanoparticles to cause DNA mutation and induce major structural damage to mitochondria, even resulting in cell death. Size is therefore a key factor in determining the potential toxicity of a particle. How these nanoparticles behave inside the body is still a major question that needs to be resolved. There is a responsibility to test and optimize these new nanomaterials early during the development process to eliminate or ameliorate identified toxic characteristics.     

env chimeric virus technology for evaluating human immunodeficiency virus susceptibility to entry inhibitors

We describe the development of chimeric virus technology (CVT) for human immunodeficiency virus (HIV) type 1 (HIV-1) env genes gp120, gp41, and gp160 for evaluation of the susceptibilities of HIV to entry inhibitors. This env CVT allows the recombination of env sequences derived from different strains into a proviral wild-type HIV-1 clone (clone NL4.3) from which the corresponding env gene has been deleted. An HIV-1 strain (strain NL4.3) resistant to the fusion inhibitor T20 (strain NL4.3/T20) was selected in vitro in the presence of T20. AMD3100-resistant strain NL3.4 (strain NL4.3/AMD3100) was previously selected by De Vreese et al. (K. De Vreese et al., J. Virol. 70:689-696, 1996). NL4.3/AMD3100 contains several mutations in its gp120 gene (De Vreese et al., J. Virol. 70:689-696, 1996), whereas NL4.3/T20 has mutations in both gp120 and gp41. Phenotypic analysis revealed that NL4.3/AMD3100 lost its susceptibility to dextran sulfate, AMD3100, AMD2763, T134, and T140 but not its susceptibility to T20, whereas NL4.3/T20 lost its susceptibility only to the inhibitory effect of T20. The recombination of gp120 of NL4.3/AMD3100 and gp41 of NL4.3/T20 or recombination of the gp160 genes of both strains into a wild-type background reproduced the phenotypic (cross-)resistance profiles of the corresponding strains selected in vitro. These data imply that mutations in gp120 alone are sufficient to reproduce the resistance profile of NL4.3/AMD3100. The same can be said for gp41 in relation to NL4.3/T20. In conclusion, we demonstrate the use of env CVT as a research tool in the delineation of the region important for the phenotypic (cross-)resistance of HIV strains to entry inhibitors. In addition, we obtained a proof of principle that env CVT can become a helpful diagnostic tool in assessments of the phenotypic resistance of clinical HIV isolates to HIV entry inhibitors.     

Prognostic importance of chromosome number in 136 untreated children with acute lymphoblastic leukemia

Leukemia cell karyotypes were determined at diagnosis for 136 of 159 consecutive patients with acute lymphoblastic leukemia (ALL) who were followed for up to 35 mo. Ninety patients (67%) had abnormal karyotypes. Five chromosome categories were designated, based on the distribution of modal numbers: hyperdiploid greater than 50 (n = 41), hyperdiploid 47-50 (n = 18), pseudodiploid (n = 28), normal (n = 46), and hypodiploid (n = 3). Treatment response was assessed for the categories in terms of time to failure (induction failure, first relapse, or death). Children in the hyperdiploid greater than 50 category had the best responses to treatment, with only 2 failures, and those in the pseudodiploid category had the poorest (p less than 0.001). The remaining 3 chromosome categories had intermediate responses and formed a third prognostic group. This same influence of chromosome number on time to failure was evident within the 2 clinical prognostic groups: high risk, signified by a leukocyte count greater than 100 X 10(9)/liter, meningeal leukemia, mediastinal mass, or the presence of blasts that formed rosettes with sheep erythrocytes at 37 degrees C, and standard risk, indicated by the absence of these features. The influence of chromosome number on time to failure was also the same within the historically favorable prognostic group that had common ALL. Results of a multivariate analysis indicated that chromosome number was the strongest single predictor of outcome (p less than 0.001) and was the only variable that added significant prognostic information to leukocyte count (p less than 0.001). The combination of chromosome number and leukocyte count should more clearly distinguish patients with ALL at low or high risk of relapse.