Brief Communication: Role of Nuclear Background and in vivo Environment in Variable Segregation Behavior of the Aging-Dependent T414G Mutation at Critical Control Site for Human Fibroblast mtDNA Replication

Previous work had shown a large accumulation (up to 50% of mtDNA) of a noninherited T414G transversion at a critical control site for mtDNA replication in skin fibroblasts from the majority of human subjects above 65 years old, and its absence in younger individuals. In the present studies, long-term in vitro culture of several fibroblasts populations carrying the heteroplasmic T414G mutation revealed an outgrowth of the mutant cells by wild-type cells. This observation supported the previous conclusion that the mutation accumulation is an in vivo phenomenon, while, at the same time, indicating intrinsic physiological differences between mutant and wild-type cells. Furthermore, subcloning experiments revealed a striking mosaic distribution of the mutation in the original fibroblasts populations, as shown by its presence, in heteroplasmic or homoplasmic form, in a fraction (18–32%) of the fibroblasts, and its absence in the others. In other investigations, transfer of mitochondria from mutation-carrying fibroblasts into mtDNA-less 143B.TK^–0 206 cells revealed the persistence of the mosaic distribution of the mutation, however, with a near-complete shift to homoplasmy. The generality of the latter phenomenon would exclude a founder effect by one or few mitochondria in the transformation experiments, and would rather point to the important role of the nuclear background in the in vitro behavior of the T414G mutation. The stability of the homoplasmic mutation in ⁰ cell transformants provides a powerful tool for analyzing its biochemical effects.     

IL-10抑制AVP诱导大鼠心脏成纤维细胞CaN活性

目的：研究白细胞介素10（IL-10）对精氨酸血管加压素(AVP)诱导大鼠心脏成纤维细胞(CFs)钙调神经磷酸酶（CaN）活性的影响。方法:用培养的新生SD大鼠CFs，四氮唑盐(MTT)比色法检测CFs增殖，流式细胞仪检测细胞周期，分光光度法测定CaN活性。结果:（1）10-7 mol/L AVP组CFs的吸光度（A490）明显高于对照组（P<0.01）。IL-10呈浓度依赖性下调 AVP诱导的CFs的A490值（P<0.05或P<0.01）。IL-10本身对CFs的增殖无抑制作用。（2）10-7 mol/L AVP组CFs的S期百分率及增殖指数均明显高于对照组（均P<0.01）；10-6 g/L IL-10+10-7 mol/LAVP组S期百分率及增殖指数均明显低于AVP组（P<0.01）。（3）10-7 mol/L AVP组CaN活性明显高于对照组（P<0.01）；10-8、10-7、10-6和10-5g/L +10-7 mol/L AVP组的CaN活性均明显低于AVP组（P<0.01），但仍高于对照组（P<0.01或P<0.05）。IL-10呈浓度依赖性下调 AVP诱导CFs的CaN活性。结论:IL-10具有抑制AVP诱导CFs增殖和下调CFs的CaN活性的作用，这可能对预防和逆转心脏重构有一定的价值。     

慢病毒介导的外源基因体外投递系统的建立

目的针对不同哺乳类细胞建立相应的慢病毒体外感染体系，以建立慢病毒介导的外源基因体外投递系统。方法按Invitrogen公司推荐的标准程序进行慢病毒（携带EGFP基因）包装（脂质体介导的瞬时转染）、超速离心浓缩和保存等，随后用病毒上清或浓缩后的病毒感染293FT细胞，24—48h后荧光显微镜下观察是否见绿色荧光以证实慢病毒是否成功生产；将携带EGFP基因的病毒上清或浓缩后的病毒分别加入内含293FF细胞、小鼠ES细胞、小鼠胚胎成纤维细胞（MEFs）或小鼠睾丸生殖细胞的培养板孔内，感染6—12h后，用相应培养基替换感染液，数天后荧光显微镜下观察是否见绿色荧光以证实慢病毒是否成功感染不同哺乳类细胞。结果按标准程序生产的携带EGFP基因慢病毒（病毒上清或浓缩后的病毒）成功高效率感染293FF细胞、MEFs或小鼠睾丸生殖细胞；用浓缩后的病毒（携带EGFP基因）感染小鼠ES细胞，亦可获得EGFP阳性的ES细胞克隆。结论熟练掌握了慢病毒包装、浓缩及鉴定等技术，同时针对不同哺乳类细胞建立了相应的慢病毒介导的外源基因体外传递系统，这些为相关后续研究打下了良好的基础。     

Genetics of the low density lipoprotein receptor:

Fibroblast association (plasma membrane binding plus intracellular accumulation) and degradation of radioiodinated low density lipoprotein (125I-LDL) index plasma membrane LDL receptor activity. Cultured fibroblasts from 23 subjects affected with familial hypercholesterolemia (HC) and from 95 subjects without HC (non-HCs) were tested for 125I-LDL association and degradation. Both LDL receptor activity indices were twice as high in non-HC and HC heterozygous cell strains. This is compatible with a major gene effect on LDL receptor activity. However, a considerable overlap between non-HC and HC heterozygous values was found in the 125I-LDL association assay [median (range) 970 (330-2500), and 450 (250-490), respectively] and in the degradation assay [median (range) 810 (280-2020), and 470 (160-790), respectively]. The values are expressed as ng 125I-LDL X mg cell protein-1 X 4.5 h-1. These great overlaps in the LDL receptor activity indices support the view that the influence of LDL receptor activity on the HC phenotype may be smaller than believed previously. Furthermore, for the diagnosis of HC, these LDL receptor activity assays are far more expensive and have less sensitivity and specificity than simple serum cholesterol determination. The LDL receptor-dependent 125I-LDL association values for the HC heterozygous individuals clustered into four groups. Family data supported the hypothesis that this variation could be due to four different LDL receptor variants, each coded for by different alleles at the LDL receptor locus. If confirmed, this finding may have implications for the understanding of the variable expression of HC and also of the genetic impact on lipoprotein metabolism and susceptibility to atherosclerosis in non-HCs.     

人成纤维细胞在裸鼠体内生长和胶原分泌的观察

目的观察人成纤维细胞注射移植后是否在裸鼠体内增殖并分泌胶原。方法将经原代培养的2×1010L-1人成纤维细胞1mL注射于BALB/CNU裸鼠真皮内,于1、2和3个月处死取材,行HE和Ⅰ、Ⅲ型胶原免疫组化染色。结果在1、2和3个月时可以观察到人成纤维细胞在裸鼠体内呈分裂象,随着时间的推移细胞外基质Ⅰ、Ⅲ型胶原分泌量呈增多趋势。结论人成纤维细胞注射移植裸鼠后,能够自行分裂、增殖并分泌人Ⅰ、Ⅲ型胶原,为自体成纤维细胞作为移植材料,发挥充填功能的持久性提供了理论依据。     

Elevated expression in situ of selectin and immunoglobulin superfamily type adhesion molecules in retroocular connective tissues from patients with Graves' ophthalmopathy.

Activation of certain adhesion molecules within vascular endothelium and the surrounding extravascular space is a critical event in the recruitment and targeting of an inflammatory response or autoimmune attack to a particular tissue site. We have recently demonstrated that the adhesion of lymphocytes to cultured retroocular fibroblasts obtained from patients with Graves' ophthalmopathy (GO) is mediated predominantly by the interaction of lymphocyte function-associated antigen-1 (LFA-1), expressed on lymphocytes, with intercellular adhesion molecule-1 (ICAM-1), expressed by these cells following exposure to interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), IL-1 alpha or purified thyroid-stimulating immunoglobulins. We now report the expression and localization in situ of several adhesion molecules, ICAM-1, endothelial leucocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and LFA-3 in retroocular tissues derived from patients with severe GO (n = 4) and normal individuals (n = 3). Serial cryostat sections of tissue specimens were processed for immunoperoxidase staining using various MoAbs against ICAM-1, ELAM-1, VCAM-1 and LFA-3. In addition, consecutive sections were stained with MoAbs against LFA-1, CD45RO (UCHL-1)DR-human leucocyte antigen (HLA-DR), CD11b/CD18 (Mac-1), and CD11c/CD18 (p150,95). In GO-retroocular tissues, strong immunoreactivity for ICAM-1 and LFA-3 was detected in blood vessels (> 90%), in perimysial fibroblasts surrounding extraocular muscle fibres, and in connective tissue distinct from extraocular muscle. No ICAM-1 or LFA-3 immunoreactivity was present in extraocular muscle cells themselves. ICAM-1 and LFA-3 immunoreactivity in normal tissues was minimal or absent both in connective and muscle tissues. Vascular endothelium was strongly positive for ELAM-1 and VCAM-1 in GO-retroocular tissues, while VCAM-1 immunoreactivity was minimal (< 5% of blood vessels) and ELAM-1 immunoreactivity was generally absent in normal retroocular tissue. LFA-1-expressing, activated mononuclear cells and memory T lymphocytes (CD3+/CD45RO+) were only detected in GO-retrocular tissues, and were mainly localized around blood vessels and in areas of ICAM-1-expressing connective and perimysial tissue. HLA-DR expression was restricted to GO-tissue specimens, with strong immunoreactivity detected in blood vessels, macrophages and connective tissue and perimysial fibroblasts. No HLA-DR was detectable in extraocular muscle cells. In conclusion, infiltration of the orbit in GO by mononuclear cells, and their targeting within the orbit, may depend upon the coordinate expression of certain adhesion and MHC molecules.(ABSTRACT TRUNCATED AT 400 WORDS)     

精神分裂症病人大脑两半球功能整合的实验研究

目的：检查精神分裂症患者可能存在的大脑两半球功能整合缺陷。方法：对20名精神分裂症患者和20名正常对照者进行不同复杂度汉字“同-异”判断的半视野速示实验。结果：①“同”判断的正确反应时（895．4毫秒）显著长于“异”判断（767．0毫秒）（F=87．44，P〈0．001），“同”判断的正确反应百分数（62．70）也显著低于“异”判断（95．30）（F=74．32，P〈0．001），表明“同”判断明显难于“异”判断；②患者和正常者一样，“异”判断的正确反应时和正确反应百分数在左视野（右半球）呈现、右视野（左半球）呈现和两视野（两半球）同时呈现三种条件之问均未出现显著差异；③正常人的“同”判断在两视野（两半球）同时呈现条件的正确反应时（674．8～743．4毫秒）明显快于左视野（右半球）（795．4—820．5毫秒）（t=2．89～4．57，均P〈0．001）和右视野（左半球）（798．6—857．1毫秒）（t=2．99—4．51，均P〈0．001），而病人没有出现两视野（两半球）对“同”判断的这种优势效应；④两视野（两半球）同时呈现条件下正常人“同”判断的正确反应百分数（88．3～89．5）与“异”判断（94．5—95．4）没有显著差异，而病人“同”判断的正确反应百分数（69．4—74．1）仍明显低于“异”判断（94．4—96．5）（t=2．39—2．60，均P〈0．05）。结论：精神分裂症患者仅在相对较难的“同”判断任务加工中表现出大脑两半球的功能整合缺陷。     

Critical role for SV40 small-t antigen in human cell transformation

Defining the ability of simian virus 40 (SV40) to transform human cells has become of even greater importance with the increased understanding that this virus may play a role in some human malignancies. This report documents the requirement for viral small-t (ST) antigen in large-T (LT)-driven transformation of primary fibroblasts, a requirement that cannot be met by a well-known oncogene, c-Ha-ras (EJ-ras), which can cooperate with LT in rodent systems. The cellular gene telomerase is not essential for transformation, although transformed clones are not immortal without it. Similarly, an immortal mesothelial cell line has been developed using LT and telomerase. Immortalized mesothelial cells are morphologically normal, but can be transformed by introduction of ST, or ST + ras, but not by ras alone. It is likely that ST will be required along with LT for transformation of most human cell types.