肺癌组织中线粒体基因组4977 bp大片段缺失状况分析

为探讨线粒体（mt）DNA 4977 bp大片段缺失和肿瘤间的相关性,我们检测了mt DNA 4977 bp大片段缺失在肺癌组织、癌旁正常组织及非癌患者肺组织的分布频率,并分析了缺失与患者年龄、吸烟因素、肺癌组织病理类型等的关系。     

中国布依族、苗族人群线粒体DNA Region V区的遗传多态性

目的 研究中国布依族、苗族人群线粒体DNA Region V区的遗传多态性。方法 采用PCR直接测序法对布依族（96份）及苗族人（90份）样本线粒体DNA Region V区进行序列分析。结果 在布依族及苗族样本中只发现标准型和短型两种多态，短型多态（即9bp缺失）频率在布依族、苗族人群中分别为31．1％和33．3％。结论 中国布依族、苗族人群线粒体DNA Region V区有相似的多态性，而与其他民族或人种有一定差异。     

贵州苗族、布依族、侗族人群线粒体DNA 9 bp序列缺失频率分析

目的 调查贵州苗族、布依族、侗族人群线粒体DNA细胞色素氧化酶Ⅱ和t RNALys基因间小非编码Ⅴ区串联重复序列9 bp的缺失频率.方法 采用聚合酶链反应-聚丙烯酰胺凝胶方法及DNA序列分析法对105名苗族、97名布依族、102名侗族的男性个体线粒体DNA的9 bp缺失多态频率进行分析.结果 在304名男性中仅发现标准型和短型(即9 bp缺失)两种多态,缺失频率为23.0％(70/304).其中苗族缺失频率为28.6％(30/105)、布依族为26.8％(26/97)、侗族为13.7％(14/102).三者之间的差异具有统计学意义(P＜0.05).结论 贵州苗族、布依族、侗族人群线粒体DNA 9 bp缺失基因频率均较高,三者之间差异有统计学意义.     

CRTER杂志“成纤维细胞培养”的组稿内容

<正>○羟基喜树碱与人病理性瘢痕成纤维细胞的增殖○转化生长因子β1对长波紫外线照射皮肤成纤维细胞线粒体DNA4977bp缺失的影响○雷公藤、人参与芳维甲酸乙酯对培养光老化真皮成纤维细胞的影响     

体外受精-胚胎移植中卵丘颗粒细胞mtDNA4977bp缺失的研究

目的探讨高龄患者卵丘颗粒细胞mt DNA结构的完整性,为卵丘颗粒细胞mt DNA结构的完整性在辅助生殖技术中的应用提供理论依据。方法将接受体外受精-胚胎移植(IVF-ET)治疗的72例女性患者分为高龄组(年龄≥38岁)和非高龄组(年龄38岁),收集其卵丘颗粒细胞,应用PCR方法检测mt DNA4977bp的缺失情况。结果高龄组患者的获卵数、优胚率及妊娠率均明显低于非高龄组(P0.05)。两组患者均未检测到卵丘颗粒细胞mt DNA4977bp的缺失。结论接受IVF-ET治疗的女性患者,无论高龄与否,卵丘颗粒细胞mt DNA结构基本完整。     

线粒体脑肌病的影像学表现

线粒体病：是由线粒体DNA（mtDNA）和细胞核DNA（nDNA）编码线粒体相关蛋白的基因突变,导致线粒体的结构及功能异常,而引起细胞呼吸链及能量代谢障碍的一种多系统受累疾病（骨骼肌、脑、心、周围神经）,线粒体几乎存在人体所有细胞内,脑和肌肉组织线粒体含量丰富。病变累及骨骼肌称线粒体肌病,如中枢神经系统同时受累称线粒体脑肌病。线粒体mtDNA的突变（位点突变、缺失、重复及丢失）引起不同类型,临床呈现多个症候群。     

线粒体DNA损伤与细胞凋亡

细胞核DNA（nuclear DNA,nDNA）损伤后诱导细胞凋亡的信号转导途径已经逐渐清晰,而线粒体DNA（mitochondrial DNA,mtDNA）损伤与细胞凋亡之间的关系尚有待进一步明确.目前已有研究结果表明：mtDNA断裂、缺失或功能缺陷能够显著影响细胞凋亡发生率;线粒体缺失细胞（p0细胞）同其亲代细胞相比,对多种凋亡诱导因素的反应存在显著差异;ROS的产生并非mtDNA损伤诱导凋亡的必要条件,mtDNA损伤断裂本身可能启动了凋亡的级联反应.但mtDNA的损伤,在细胞凋亡的信号转导途径具体扮演何种角色,还有待深入研究.     

遗传性共济失调一家系中发现的线粒体DNA突变

目的探索遗传性共济失调（hereditary ataxia，HA）家系中的线粒体DNA突变。方法采用聚合酶链反应扩增两个HA家系及35名健康对照者外周血白细胞的线粒体DNA，并对PCR产物进行单链构象多态性分析，对出现异常条带者进行线粒体DNA片段测序。结果其中一家系中的2例患者及1例无临床症状亲属检测到线粒体DNA11893（A→G）点突变。结论遗传性共济失调的发生、发展可能与线粒体DNA11893（A→G）点突变有关。     

阿尔茨海默病患者血液细胞线粒体内细胞色素C氧化酶亚基Ⅱ基因存在缺失

目的 调查25例老年痴呆患者血细胞线粒体中细胞色素C氧化酶亚基Ⅱ基因的突变情况,探讨线粒体DNA突变与阿尔茨海默病(AD)性老年痴呆发生发展的关系。方法 采用微量法提取血细胞总DNA直接作为PCR模板,进行巢式PCR扩增,最后采用DNA序列分析鉴定突变。结果在正常老人组,只扩增了280bp的线粒体细胞色素C氧化酶亚基Ⅱ基因(COX2)扩增片段,而在老年痴呆患者中出现了464bp和280bp的多态性扩增片段,并且发现了1个320bp的新的线粒体DNA缺失片段,1位AD患者的COX2基因存在一种新的缺失后重组现象,COX2基因的1条单链在np7503处断裂,另1条单链在np7785处断裂,这两个断裂的游离片段通过插入1个额外的胞嘧啶核苷酸重新连接起来。结论 老年痴呆患者中的COX2基因存在片段扩增多态性。     

线粒体DNA与人精子活力间的相关性分析

目的 探讨线粒体ＤＮＡ与人精子活力间的关系。方法 用长链ＰＣＲ技术,对６０例精子活力正常和４０例精子活力异常不育患者的精子线粒体ＤＮＡ（ｍｔＤＮＡ）进行了多重缺失的分析。结果 两组不育患者中共有８例具有ｍｔＤＮＡ的多重缺失（其中精子活力正常不育患者６名,精子活力异常不育患者２名）,但缺失型ｍｔＤＮＡ（Ｓ５除外）在总ｍｔＤＮＡ中所占比例很小（０．１６％～１．８５％）,１例精子活力正常的不育患者（Ｓ５     

Detection of damage to the mitochondrial genome in the oncocytic cells of Warthin's tumour

Warthin's tumour of the salivary glands is composed of oncocytic cells containing excessive numbers of mitochondria which show frequent structural abnormalities and reduced metabolic function. Recent evidence of a strong association between cigarette smoking and the occurrence of Warthin's tumour prompted this study, to look for evidence of damage to mitochondrial DNA (mtDNA) that could be the result of an increase in oxidative stress; two-colour fluorescence in situ hybridization (FISH) was developed to show the distribution of mitochondria with deleted mtDNA in paraffin wax-embedded material. Approximately 10% of mtDNA bears the 'common' 4977 bp deletion. Using the polymerase chain reaction (PCR), the 4977 bp deletion was further quantified, in Warthin's tumour and age-matched normal parotid control tissue. Whilst the deletion was present in all parotid tissue, its presence was significantly higher in oncocytic tumour cells. In a small number of controls, there was a trend towards higher concentrations of the deletion in smokers.     

The mitochondrial DNA 4977‐bp deletion and copy number alteration in Han Chinese samples with uterine fibroids

Uterine fibroids (UFs) are the most common benign neoplasms, but their pathogenesis is not completely understood. Thus far, alterations in the mitochondrial DNA (mtDNA) content and the mtDNA 4977‐bp deletion level in UFs, as well as the corresponding nontumorous tissue, have remained elusive. To test whether large mtDNA deletions and mtDNA content are involved in the pathogenesis of UFs, a total of 309 UF tissues and 28 paired adjacent myometrium from 270 UF patients were enrolled for the analysis of large mtDNA deletions and mtDNA content through the use of nested PCR and qPCR techniques, respectively. In our samples, a 4977‐bp deletion was identified: 36 out of 309 UF tissues (11.56%) and 15 out of 28 (53.57%) paired adjacent myometrium were detected to harbor the 4977‐bp deletion. In addition, a novel 4838‐bp mtDNA deletion was identified in three UF tissues, and other different sizes of deleted fragments (4910, 4926, 5135‐bp) were also found in UFs for the first time. Furthermore, older age was significantly associated with an mtDNA large deletion in the paired adjacent myometrium. We also found that increased mtDNA content and higher expression of ND1 occurred in solitary fibroids compared to adjacent myometrium. In conclusion, we identified a lower frequency of mtDNA large deletions and some novel large deletion in UFs for the first time. Furthermore, there was a general increase of mtDNA copy number during solitary UF development. Although the definite mechanism by which mtDNA was altered is supposed to be further confirmed, it will be helpful for further studies on the pathological mechanism of UFs.     

Mitochondrial DNA content and 4977 bp deletion in unfertilized oocytes

Previous studies analysing the incidences of mitochondrial DNA (mtDNA) deletions and mtDNA content in unfertilized oocytes in relation to donors' age have been controversial. The objective of the study was to compare these two parameters in unfertilized oocytes and relate them to the donors' age. Fifty-two women donated 155 unfertilized metaphase II (MII) oocytes. The incidence of 4977 bp deletion was 34.6%, and the mtDNA copy number was 598 350 +/- 265 862. Women >or=35 years of age had a significantly higher incidence of 4977 bp deletion, lower mtDNA copy number, higher FSH level and poorer ovarian response when compared with younger women. The mtDNA copy number was negatively correlated with the donor's age. The higher incidence of mtDNA deletion and lower mtDNA copy number in older women suggested that these two parameters may reflect ovarian ageing.     

Polymorphisms of glutathione S-transferase M1 and male infertility in Taiwanese patients with varicocele

BACKGROUND: To examine glutathione S-transferase M1 (GST M1) gene polymorphism and male infertility in Taiwanese patients with varicocele, 80 young male patients with varicocele (group 1), 62 young male patients with subclinical varicocele (group 2) and 60 normal young males (group 3) were recruited in this study. METHODS: GST M1 null homozygous genotype [GST M1-] and the occurrence of a 4977 bp deletion of sperm mitochondrial DNA (mtDNA) were determined by polymerase chain reaction. The 8-hydroxy-2'-deoxyguanosine (8-OHdG) content of sperm DNA was measured by high-performance liquid chromatography. RESULTS: The frequencies of GST M1- genotype were 43.8, 41.9 and 45% for patients in groups 1, 2 and 3 respectively. In group 1 patients with GST M1- genotype, the frequency of the presence of the 4977 bp deletion in sperm mtDNA (54.3%) was significantly higher than that of the patients without the 4977 bp deletion in sperm mtDNA (45.7%, OR: 2.63, P = 0.04). Patients of groups 1 and 2 with GST M1- genotype had significantly higher 8-OHdG content in sperm DNA and lower protein thiols and ascorbic acid in seminal plasma than those with GST M1+ genotype. CONCLUSION: GST M1- genotype predisposes to increased oxidative damage to sperm of patients with varicocele.     

Familial childhood onset neuropathy and cirrhosis with the 4977bp mitochondrial DNA deletion

The common 4977 base pair mitochondrial deletion has been identified in association with a number of distinct clinical phenotypes. These include the Kearns-Sayre syndrome, the Pearson marrow-pancreas syndrome, and chronic progressive external ophthalmoplegia. We report the clinical and pathological findings in two siblings in whom the 4977 base pair mitochondrial DNA deletion was identified in muscle-derived mitochondrial DNA. One sibling manifested early onset liver and renal failure, and both developed prominent peripheral sensorimotor neuropathy. These clinical findings have not been previously described in association with the 4977bp mtDNA deletion and thus represent a further expansion of the spectrum of mitochondrial disease.     

Mitochondrial DNA common deletion in the human eye: a relation with corneal aging

The most frequent mitochondrial DNA (mtDNA) mutation is a 4977 bp deletion known as the common deletion (mtDNA(CD4977)). mtDNA(CD4977) is related to skin photo-aging and to chronological aging of cells with high-energy demands such as neurons and muscle cells. The human eye contains both sun-exposed (cornea, iris) and high-energy demand structures (retina). In this study, we employed a highly sensitive quantitative PCR technique to determine mtDNA(CD4977) occurrence in different structures of the human eye. We found that the cornea, the most anterior structure of the eye, contains the highest amount of mtDNA(CD4977) (2.6%, 0.25% and 0.06% for the cornea, iris and retina, respectively). Within the cornea, mtDNA(CD4977) is almost exclusively found in the stroma, the cellular layer conferring transparency and rigidity to the human cornea (8.59%, 0.13% and 0.05% in the stroma, endothelium and epithelium, respectively). Moreover, we show that mtDNA(CD4977) accumulates with age in the corneal stroma. Taken together, our results suggest that mtDNA(CD4977) is related to photo-aging rather than chronological aging in the human eye. Similar to the involvement of mtDNA(CD4977) in skin photo-aging phenotypes, we believe that the clinical manifestations of corneal aging, including clouding and stiffening, are associated with the accumulation of mtDNA(CD4977) in the corneal stroma.     

Mitochondrial DNA deletions are rare in the free radical-rich retinal environment

We measured the levels of a somatic, 4977 bp deletion of mitochondrial DNA (mtDNA⁴⁹⁷⁷) in paired neural retinal and optic nerve tissues from 14 adults and 1 infant using a quantitative PCR assay. MtDNA is prone to free radical damage, and areas in the brain that are exposed to high levels of free radicals are observed to accumulate higher levels of the mtDNA⁴⁹⁷⁷ deletion. The levels of mtDNA deletions also increase with age in many tissues. Despite the presence of a free radical rich environment, mtDNA from the neural retina possessed extremely low mtDNA⁴⁹⁷⁷ levels (0.0001–0.001%). Deletion levels were always lower than those in the optic nerve from the same eye and do not appear to increase with age. Our results suggest that antioxidant defenses in the neural retina are effective in protecting mtDNA against oxidative damage.     

Response to “genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) in ethnic populations in Texas; a report of a novel MTHFR polymorphic site,G1793A”

The common 4977 base pair mitochondrial deletion has been identified in association with a number of distinct clinical phenotypes. These include the Kearns‐Sayre syndrome, the Pearson marrow‐pancreas syndrome, and chronic progressive external ophthalmoplegia. We report the clinical and pathological findings in two siblings in whom the 4977 base pair mitochondrial DNA deletion was identified in muscle‐derived mitochondrial DNA. One sibling manifested early onset liver and renal failure, and both developed prominent peripheral sensorimotor neuropathy. These clinical findings have not been previously described in association with the 4977bp mtDNA deletion and thus represent a further expansion of the spectrum of mitochondrial disease. © 2002 Wiley‐Liss, Inc.     

Multiple deletions of mitochondrial DNA are associated with the decline of motility and fertility of human spermatozoa

Sperm motility is one of the major determinants of male fertility and is required for successful fertilization. In a previous study, we demonstrated that the occurrence and accumulation of the 4977 bp deletion of mitochondrial DNA (mtDNA) is associated with diminished fertility and motility of human spermatozoa. The possible relationship between multiple deletions of mtDNA and the decline of fertility and motility in human spermatozoa was further explored in 36 subjects including subfertile and infertile males in this study. Using long- range polymerase chain reaction (PCR), we confirmed the 4977 bp deletion and identified two novel deletions of 7345 and 7599 bp of mtDNA in the spermatozoa with poor motility. We used Percoll gradients to fractionate spermatozoa with differing motility, and then screened for two novel large-scale deletions of the mtDNA. The results showed that the ratio of the deleted mtDNA in the spermatozoa with poor motility and diminished fertility were significantly higher than those in the spermatozoa with good motility and fertility. In addition, we found that the frequencies of the three large-scale deletions in the spermatozoa from patients with primary infertility and oligoasthenozoospermia were higher than those of the fertile males. Our findings suggest that mtDNA deletions may play an important role in some pathophysiological conditions of human spermatozoa.      

Association of mitochondrial DNA damage with aging and coronary atherosclerotic heart disease

The role of somatic mitochondrial DNA (mtDNA) damage in human aging and progressive diseases of oxidative phosphorylation (OXPHOS) was examined by quantitating the accumulation of mtDNA deletions in normal hearts and hearts with coronary atherosclerotic disease. In normal hearts, mtDNA deletions appeared after 40 and subsequently accumulated with age. The common 4977 nucleotide pair (np) deletion (mtDNA⁴⁹⁷⁷) reached a maximum of 0.007%, with the mtDNA⁷⁴³⁶ and mtDNA^10,422 deletions appearing at the same time. In hearts deprived of mitochondrial substrates due to coronary artery disease, the level of the mtDNA⁴⁹⁷⁷ deletion was elevated 7–220-fold over age-matched controls, with the mtDNA⁷⁴³⁶ and mtDNA^10,422 deletions increasing in parallel. This cumulative mtDNA damage was associated with a compensatory 3.5-fold induction of nuclear OXPHOS gene mRNA and regions of ischemic hearts subjected to the greatest work load (left ventricle) showed the greatest accumulation of mtDNA damage and OXPHOS gene induction. These observations support the hypothesis that mtDNA damage does accumulate with age and indicates that respiratory stress greatly elevates mitochondrial damage.