Mutações em genes da biologia dos telômeros, causando o seu encurtamento, são as bases moleculares de um grupo heterogêneo de doenças denominadas telomeropatias. O protótipo das telomeropatias é a disceratose congênita (DC), uma falência de medula óssea, caracterizada por sinais mucocutâneos e anemia aplástica (AA). Além da DC e AA, a fibrose pulmonar (FP) e a cirrose hepática (CH) também fazem parte do espectro das telomeropatias. Como pulmão e fígado são órgãos com baixa taxa proliferativa, suspeita-se que existe outros componentes celulares interagindo com os telômeros para o estabelecimento dessas doenças. Diferentes abordagens vêm estabelecendo uma relação entre e a biologia dos telômeros e as mitocôndrias. No entanto, ainda não se sabia sobre o funcionamento mitocondrial em células primárias de pacientes com telomeropatias. No nosso estudo, utilizamos fibroblastos dermais de indivíduos saudáveis (n=4) e de pacientes (n=6), diagnosticados com diferentes telomeropatias (AA, DC, FP e CH) e telômeros abaixo do 10º percentil (curtos para a idade). Ao avaliarmos parâmetros mitocondriais, observamos um fenótipo senescente, nas células dos pacientes, que refletiu num aumento na massa mitocondrial (85%), no número de copias de DNA mitocondrial, no consumo de oxigênio (71%) e na produção de superóxidos (74%), precursor das espécies reativas de oxigênio (EROs) mitocondriais. O superóxido levou a um aumento na expressão de antioxidantes, como a SOD1 e a UCP1. Dessa maneira, o estresse oxidativo gerado pelas EROs mitocondriais parece ter um papel fundamental na patogênese das telomeropatias. Além disso, sequenciamos amostras de sangue periférico de outros 72 pacientes com falência medular, com telômeros curtos e normais, para compararmos a taxa de variantes somáticas entre os grupos. Observamos que os pacientes com falência medular e telômeros curtos apresentaram maiores frequências de variantes somáticas. Supomos que o aumento da taxa de variantes somáticas possa ser consequência do desequilíbrio redox, observado nas células dos pacientes, causando danos no DNA das células-tronco hematopoéticas.Estudos como esse podem basear discussões sobre o uso de terapias antioxidantes em pacientes com telomeropatias / Mutations in telomere-related genes are the molecular basis of a phenotypically heterogeneous group of disorders that are collectively termed telomeropathies. The prototype of telomeropathies is the dyskeratosis congenita (DC), an inherited bone marrow failure characterized by mucocutaneous stigmata and aplastic anemia (AA). In murine telomerase knockout models, telomere shortening provokes mitochondrial deficiency and increases reactive oxygen species (ROS) production. However, the mitochondrial function in human telomeropathies has not been addressed. We evaluated mitochondrial parameters in fibroblasts from four healthy individuals (controls) and six patients with inherent bone marrow failure (DC and AA), carrying pathogenic variants in TERC, DKC1, RTEL1 and POT1 genes and, consequently, telomere shortening (<10th percentile). Patient fibroblasts displayed an 85% increment in mitochondrial mass, resulting in a 71% increase in oxygen consumption in the state of maximum respiration (ETS) compared to controls. As a consequence, mitochondrial ROS production was 74% higher in patients\' fibroblasts than in controls. Increased ROS level may explain the overexpression of SOD1 and UCP1 observed in patient cells. We further assessed the mitochondrial DNA (mtDNA) copy number in fibroblasts and peripheral blood of patients with telomere shortening. The mtDNA content was significantly higher in patients compared to controls. These findings indicate that mitochondria are affected in human telomere diseases and may play a role in disease development. Furthermore, overproduction of mitochondrial ROS could induce oxidative stress and result in somatic mutations in hematopoietic stem-cells, causing clonal disorders in patients with telomeropathies

by Chong Yin Yue. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 146-161). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract (English/Chinese) --- p.ii / Contents --- p.vi / List of Tables --- p.ix / List of Figures --- p.xi / Chapter I. --- INTRODUCTION --- p.1 / Chapter I.1. --- Central Nervous System Tumors --- p.1 / Chapter I.2. --- Histopathological Classification of Gliomas --- p.4 / Chapter I.2.1. --- Astrocytic Tumors --- p.4 / Chapter I.2.1.1. --- Diffuse Astrocytomas --- p.4 / Chapter I.2.1.1.1. --- Low Grade Diffuse Astrocytomas --- p.5 / Chapter I.2.1.1.2. --- Anaplastic Astrocytomas --- p.5 / Chapter I.2.1.1.3. --- Glioblastomas --- p.6 / Chapter I.2.1.2. --- Pilocytic Astrocytomas --- p.9 / Chapter I.2.1.3. --- Pleomorphic Xanthoastrocytomas --- p.10 / Chapter I.2.2. --- Non-Astrocytic Tumors --- p.10 / Chapter I.2.2.1. --- Oligodendroglial Tumors --- p.10 / Chapter I.2.2.2. --- Ependymal Tumors --- p.16 / Chapter I.2.2.3. --- Dysembryoplastic Neuroepithelial Tumors --- p.20 / Chapter I.3. --- Molecular Genetics in Gliomas --- p.21 / Chapter I.4. --- Telomeres and Telomerase --- p.29 / Chapter I.4.1. --- History --- p.29 / Chapter I.4.2. --- Telomeres --- p.30 / Chapter I.4.3. --- End Replication Problem --- p.32 / Chapter I.4.4. --- Telomerase --- p.34 / Chapter I.4.5. --- Telomerase Components --- p.36 / Chapter I.4.5.1. --- RNA Component --- p.36 / Chapter I.4.5.2. --- Protein Component --- p.39 / Chapter I.4.5.3. --- Catalytic Subunit --- p.40 / Chapter I.4.5.4. --- Telomeric Repeat Binding Factor 1 --- p.41 / Chapter I.4.6. --- Cellular Immortality and Aging --- p.42 / Chapter I.4.7. --- Detection of Telomerase Activity --- p.44 / Chapter I.4.7.1. --- Telomeric Repeat Amplification Protocol Assay --- p.44 / Chapter I.4.7.2. --- Other Detection Methods --- p.45 / Chapter I.4.8. --- An Overview of Telomerase Activity --- p.48 / Chapter I.4.9. --- Alternative Lengthening of Telomeres --- p.50 / Chapter I.4.10. --- Telomeres Suppressor Genes --- p.51 / Chapter I.4.11. --- Telomerase and pl6/pRb Pathway --- p.52 / Chapter I.5. --- Telomeres and Telomerase Studies in Brain Tumors --- p.54 / Chapter I.5.1. --- Telomerase Activity in Brain Tumors --- p.54 / Chapter I.5.2. --- Telomere Length in Brain Tumors --- p.57 / Chapter I.5.3. --- Telomerase RNA Component Expression in Brain Tumors --- p.57 / Chapter II. --- OBJECTIVES of STUDY --- p.59 / Chapter III. --- MATERIALS AND METHODS --- p.61 / Chapter III.l. --- Telomerase Activity Study --- p.61 / Chapter III.1.1. --- Specimens --- p.61 / Chapter III.l.2. --- Telomerase Extraction --- p.63 / Chapter III.1.3. --- Protein Concentration Measurement --- p.63 / Chapter III.1.4. --- RNase-treated Samples --- p.64 / Chapter III.l.5. --- TRAP Assay --- p.64 / Chapter III.1.5.1. --- TS Primer Labelling --- p.65 / Chapter III.1.5.2. --- TS Primer Extension And PCR Amplification --- p.65 / Chapter III. 1.6. --- Non-Denaturing Polyacrylamide Gel Electrophoresis --- p.66 / Chapter III.1.7. --- Data Analysis --- p.67 / Chapter III.1.8. --- Statistical Analysis --- p.67 / Chapter III.2. --- Telomere Length Study --- p.68 / Chapter III.2.1. --- Specimens --- p.68 / Chapter III.2.2. --- DNA Extraction --- p.70 / Chapter III.2.3. --- DNA Concentration Measurement --- p.71 / Chapter III.2.4. --- Analysis of Telomere Length by Southern Hybridization --- p.71 / Chapter III.2.4.1. --- DNA Digestion --- p.73 / Chapter III.2.4.2. --- Southern Blotting --- p.73 / Chapter III.2.5. --- Data Analysis --- p.76 / Chapter III.2.6. --- Statistical Analysis --- p.77 / Chapter III.3. --- hTERT and hTEP1 mRNA Expression Study --- p.78 / Chapter III.3.1. --- Specimens --- p.78 / Chapter III.3.2. --- RNA Extraction and DNase Treatment --- p.78 / Chapter III.3.3. --- Reverse Transcription-Polymerase Chain Reaction --- p.80 / Chapter III.3.3.1. --- Primer Design --- p.81 / Chapter III.3.3.2. --- Standard Protocol --- p.81 / Chapter III.3.4. --- Statistical Analysis --- p.84 / Chapter III.4. --- p16 and pRb Immunostaining --- p.85 / Chapter III.4.1. --- Specimens --- p.85 / Chapter III.4.2. --- Slide Preparation --- p.85 / Chapter III.4.3. --- Immunohistochemistry --- p.87 / Chapter III.4.4. --- Data Analysis --- p.88 / Chapter III.4.5. --- Statistical Analysis --- p.89 / Chapter IV. --- RESULTS --- p.90 / Chapter IV.1. --- Telomerase Activity Study --- p.90 / Chapter IV.2. --- Telomere Length Study --- p.96 / Chapter IV.3. --- hTERT and hTEPl mRNA Expression Study --- p.104 / Chapter IV.4. --- p16 and pRb Protein Expression --- p.109 / Chapter V. --- DISCUSSION --- p.115 / Chapter V. 1. --- Telomerase Activity in Gliomas --- p.115 / Chapter V.2. --- Telomere Length in Oligodendroglial and Ependymal Tumors --- p.122 / Chapter V.3. --- hTERT and hTEPl mRNA Expression in Oligodendroglial and Ependymal Tumors --- p.128 / Chapter V.4. --- Protein Expression ofpl6 and pRb in Oligodendroglial and Ependymal Tumors --- p.132 / Chapter V.5. --- Discussion on Telomerase Activity-Related Factors --- p.135 / Chapter V.6. --- Significance of Study and Clinical Application --- p.137 / Chapter V.7. --- Future Direction --- p.141 / Chapter VI. --- CONCLUSION --- p.143 / Chapter VII. --- REFERENCES --- p.146

In an effort to achieve replicative immortality, human cancer cells must avoid the constant telomere attrition that accompanies DNA replication. Cancer cells accomplish this by employing mechanisms to lengthen their telomeres. Approximately 10 percent of all cancers utilize the Alternative Lengthening of Telomeres (ALT) pathway to maintain telomere length. Although ALT is known to rely on homologous recombination between two telomeric sequences, the exact mechanism and regulators of the ALT pathway remain elusive. As common fragile sites, telomeres pose a challenge to the replication machinery. This replication challenge is exacerbated in ALT cells due to defects in nucleosome assembly, suggesting the importance of managing replication stress at telomeres in these cells. ATR (ataxia telangiectasia and Rad3-related) is an important kinase in the response to replication stress. The work in this thesis demonstrates that ATR is also a key mediator of ALT activity. Due to the highly recombinogenic state of ALT telomeres, these cells depend on ATR activity. In fact, we illustrate that small molecule inhibition and siRNA mediated loss of ATR disrupts ALT activity and promotes cell death specifically in ALT positive cancer cells. Although we establish ATR as a critical regulator and effective therapeutic target in ALT cancers, the exact mechanism of ATR in this pathway remains elusive. Recently, the chromatin remodeling enzyme SMARCAL1 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin subfamily A-like protein 1) was identified as one of the most abundant proteins bound to sites of replication stress. We demonstrate by combined immunofluorescence-FISH and chromatin immunoprecipitation that SMARCAL1 associates with ALT telomeres to resolve replication stress and maintain telomere stability. Specifically, we illustrate that siRNA mediated loss of SMARCAL1 in ALT cancer cells results in persistently stalled replication forks that collapse into DNA double strand breaks, which promotes the formation of chromosome fusions. Ultimately, we illustrate that loss of SMARCAL1 in ALT cancer cells promotes genomic instability through telomere dysfunction. Although great strides have been made in defining the ALT mechanism, the drivers of this pathway remain elusive. These studies highlight the importance of replication stress in both activation and maintenance of the ALT pathway. Our data demonstrate chronic replication stress as a key feature at ALT telomeres. Importantly, we were able to exploit this feature to identify a novel therapeutic avenue for ALT positive cancers.

No description available.

Thesis (MSc (Biomedical Technology))--Cape Peninsula University of Technology, 2017. / Background: Telomeres are DNA-proteins situated at the ends of linear chromosomes, responsible for genome stabilization. A link has been previously described between leucocyte telomere length (LTL) and age-related inflammatory disorders such as atherosclerosis, rheumatoid arthritis and cancer. Since diabetes mellitus has been described as a chronic inflammatory condition, it has been hypothesized that there is significant LTL shortening in individuals with dysglycaemia. Aim: To investigate leucocyte telomere length in patients with pre-diabetes, newly diagnosed, known diabetics on treatment and to compare the results to normoglycaemic individuals. Methods: A total of 205 eligible subjects (78% women) median age 56 years, from the Bellville-South community were followed-up between 2008 and 2011. Baseline and follow-up data collections included glucose tolerance status, anthropometric, blood pressure, lipids, insulin, γ-glutamyl transferase, cotinine, and HbA1c. In all participants, telomere length was measured using the absolute telomere q-PCR method performed on a Bio-Rad MiniOpticon Detector. Results: Although there was a change in individuals’ glycaemic status over the 3 years, no significant differences were observed in LTL across glycaemic status: (Baseline p = 0.7618, 3 Year Follow-up p = 0.2204). However, in a multiple regression model, adjusted for age and gender, LTL was negatively associated with age and GGT, and positively associated with high density lipoproteins (HDL) (all p < 0.05). Discussion and conclusion: This research study was the first longitudinal study of LTL in Africans. We show that LTL shortening is not evident within three years, nor is it associated with glycaemia. Our findings also corroborate previous notions associating LTL with age. The lack of association between LTL and glycaemia has been previously reported, however further studies are required using larger sample and broader BMI spread.

Polychlorniated Biphenyls (PCBs), a group of 209 individual congeners, are ubiquitous environmental pollutants and classified as probable human carcinogens. Hallmarks of aging and carcinogenesis are changes in telomerase activity and telomere length. I hypothesize that PCBs modulate telomerase activity and telomeres via interference in gene regulation and generation of reactive oxygen species (ROS) resulting in the dysregulation of cell growth. To explore this possibility, I exposed human skin keratinocytes (HaCaT) to a synthetic airborne PCB mixture (CAM) and individual congeners, i.e. PCB28, PCB52, PCB126 and PCB153. To mimic the chronic human exposure to PCBs and the slow process of carcinogenesis, a long term exposure period of 48 days and beyond was employed. All PCB congeners and CAM reduced telomerase activity, telomere length and cell growth. Among all PCBs, PCB126 had the most pronounced effect with reduction in telomerase activity, telomere length, hTERT and hTR gene expression and cell growth, while increasing TRF1 & TRF2 gene expression. PCB126 elicited an increase in CYP1A1 mRNA, CYP1A1 activity, DHE and DCFH oxidation levels from days 6 to 48, suggesting that increased ROS might be a causative factor for the reduction in telomerase activity and telomere length. However, transduction with hTERT and hTR subunits partly rescued telomerase activity, while treatment with PEG-catalase did not rescue telomerase activity suggesting that telomerase subunits play an important role on PCB126 induced effects on telomerase activity and telomere length. Since cells with shortened telomeres may escape crisis through telomerase reactivation, PCB126 treatment was continued until day 90. A change in growth behavior was observed from day 54 to 90, with cells recovering the proliferation rate, and increasing c-Myc, hTERT, and hTR gene expression level, re-activating telomerase activity and re-elongating telomere length. TRF1 & 2 gene expression started to decrease after day 66. From day 78, no increase in CYP1A1mRNA and its activity as well as CYP1B1, ALDH3A1, UGT1A1 and AhRRmRNA was observed suggesting that the AhR response pathway may have been altered. This study shows for the first time that PCBs initially reduce telomerase activity, telomere length, and cell growth, and can later lead to telomerase re-activation, telomere lengthening and increased cell growth with modulation of the AhR receptor pathway. This observation has broad implications for chronic PCB exposure scenarios.

Doctor of Philosophy / Activation of a telomere maintenance mechanism is a vital step in the development of most cancers and provides a target for the selective killing of cancer cells. Cancers can use either telomerase or Alternative Lengthening of Telomeres (ALT) to maintain their telomeres and inhibition of either telomere maintenance mechanism can cause cancer cells to undergo senescence or apoptosis. Although telomerase inhibitors are undergoing clinical trials, on commencing this study very little was known about the role of ALT in cancer, what proteins were involved in its mechanism and regulation and how it could be targeted clinically. The primary aim of this thesis was to develop an assay for ALT suitable for examining archived tumour specimens and to begin using it to examine the prevalence and clinical significance of ALT in cancer. This assay and gene expression analysis was also used to identify genes that are involved in or associated with the activation of the ALT mechanism, to contribute towards the overall goal of an ALT cancer therapy. The ALT mechanism involves recombination mediated replication and ALT cells have a marked increase in a range of recombinational events specifically at their telomeres. Presumably, as a consequence of this the telomere lengths of ALT cells are very heterogeneous and on average long. This can be detected by terminal restriction fragment (TRF) Southern analysis, which has been used previously as the definitive test for ALT activity. However, TRF analysis requires intact genomic DNA and is unsuitable for tumour specimens which are commonly archived by paraffin embedding. Another hallmark of ALT is ALT-associated PML bodies (APBs) which are the subset of PML bodies that contain telomeric DNA. Work done in this study to consolidate APBs as a hallmark of ALT, combined with published data, showed 29/31 ALT[+], 3/31 telomerase[+] and 0/10 mortal cell lines/strains are APB[+]. The three APB[+]/telomerase[+] cell lines identified here had an order of magnitude lower frequency of APB[+] nuclei than the ALT[+] cell lines. APBs may be functionally linked to the ALT mechanism and contain the recombination proteins that are thought to be involved in the ALT mechanism. This study, in collaboration with Dr W-Q Jiang, strengthened this functional link by demonstrating that loss of ALT activity (as determined by TRF analysis) coincided with the disruption of APBs. The detection of APBs was developed into a robust assay for ALT in archived tumour specimens using a technique of combined immunofluorescence and telomere fluorescence in situ hybridisation. It was demonstrated that the APB assay concurred exactly with the standard assay for ALT (TRF analysis) in 60 tumours for which TRF analysis gave unequivocal results. The APB assay may be a more appropriate technique in the case of tumour specimen heterogeneity, which may explain why the APB assay was able to give definitive results when TRF analysis was equivocal. We demonstrated that intratumoral heterogeneity for ALT does exist and this could explain why about 3% of tumours in this study were APB[+] but with more than a ten-fold reduction in the frequency of APB[+] nuclei. This study also made the novel discovery of single stranded C-rich telomeric DNA inside APBs which potentially could be used to make the APB assay more suitable for routine pathology laboratory use. The APB assay was used to show that ALT is a significant concern for oncology. ALT was utilised in approximately one quarter of glioblastoma multiforme (GBM), one third of soft tissue sarcomas (STS) including three quarters of malignant fibrous histiocytomas (MFH), half of osteosarcomas and one tenth of non-small cell lung carcinomas (NSCLC). Furthermore, the patients with these ALT[+] tumours had poor survival; median survivals were 2 years for ALT[+] GBM, 4 years for ALT[+] STS including 3.5 years for ALT[+] MFH and 5 years for ALT[+] osteosarcoma. ALT[+] STS and osteosarcomas were also just as aggressive as their ALT[-] counterparts in terms of grade and patient outcome. ALT status was not found to be associated with response to chemotherapy in osteosarcomas or survival in STS. ALT was however, less prevalent in metastatic STS. The APB assay was a prognostic indicator for GBM and was correlated with three fold increased median survival in GBM (although this survival was still poor). ALT was more common in lower grade astrocytomas (88% ALT[+]) than GBM (24% ALT[+]) and ALT[+] GBM had an identical median age at diagnosis to that reported for secondary GBM. It is discussed that these data indicate that ALT was indirectly associated with secondary GBM and is possibly an early event in its progression from lower grade astrocytoma. This is relevant because secondary GBM have distinct genetic alterations that may facilitate activation of the ALT mechanism. Putative repressors of ALT could explain why this study found that ALT varied among the different STS subtypes. ALT was common in MFH (77%), leiomyosarcoma (62%) and liposarcoma (33%) but rare in rhabdomyosarcoma (6%) and synovial sarcoma (9%). ALT was not found in colorectal carcinoma (0/31) or thyroid papillary carcinoma (0/17) which have a high prevalence of telomerase activity and a reduced need for a telomere maintenance mechanism (low cell turnover), respectively. A yeast model of ALT predicts that one of the five human RecQ helicases may be required for ALT. Using the APB assay to test for the presence of ALT in tumours from patients with known mutations in either WRN or RECQL4 it was demonstrated that neither of these RecQ helicases is essential for ALT. Although p53 and mismatch repair (MMR) proteins have been suggested to be possible repressors of ALT, there was no apparent increase in the frequency of ALT in tumours from patients with a germline mutation in p53 codon 273 or in colorectal carcinomas that had microsatellite instability and thus MMR deficiency. Also contrary to being a repressor of ALT but consistent with its ability to interact with a protein involved in the ALT mechanism, the MMR protein MLH1, was demonstrated to be present in the APBs of an ALT[+] cell line. To further test for genes that may be involved in the ALT mechanism or associated with its activation, RNA microarray was used to compare the gene expression of 12 ALT[+] with 12 matched telomerase[+] cell lines; 240 genes were identified that were significantly differentially expressed (p<0.005) between the ALT[+] and telomerase[+] cell lines. Only DRG2 and SFNX4 were significantly differentially expressed after adjusting for the estimated false positive rate. Overall, DRG2, MGMT and SATB1 were identified as most likely to be relevant to the ALT[+] tumours and Western analysis indicated that DRG2 and MGMT levels were down-regulated after activation of ALT and up-regulated after activation of telomerase, whereas SATB1 protein levels appeared to be up-regulated after immortalisation but to a higher degree with activation of ALT compared to telomerase. Since lack of MGMT is known to be a determinant of temozolomide sensitivity in GBM, the possibility that ALT and the APB assay could be used to predict temozolomide sensitivity is discussed. The microarray data was consistent with MGMT expression being suppressed by EGF (p < 0.05), indicating that caution may be needed with combining EGFR inhibitors with temozolomide in ALT cancers. One ALT[+] cell line which did not express MGMT had TTAA sequence in its telomeres. This could possibly have resulted from mutations due to lack of MGMT expression and a possible role for MGMT in the ALT mechanism is discussed. Further analysis of the microarray data identified two groups of co-regulated genes (p < 5x10-5): CEBPA, TACC2, SFXN4, HNRPK and MGMT, and SIGIRR, LEF1, NSBP1 and SATB1. Two thirds of differentially expressed genes were down-regulated in ALT. Chromosomes 10 and 15 had a bias towards genes with lower expression in ALT while chromosomes 1, 4, 14 and X had a bias towards genes with higher expression levels in ALT. This work has developed a robust assay for ALT in tumour specimens which was then used to show the significance of ALT in sarcomas, astrocytomas and NSCLC. It has also identified genes that could possibly be molecular targets for the treatment of ALT[+] cancers.

Telomere, the ends of chromosomes, consists of simple hexameric repeats. In human, TTAGGG repeat is found at the ends of all chromosomes. Telomeres progressively shorten with age in somatic cells, because the insufficient telomerase activity fails to compensate the progressive telomeric erosion. Thus, the reduction of telomeric length in senescent cells is believed to result from active cell division that erodes chromosomal termini. The telomere length supposed to have been an evaluation tool for aging in human. Schizophrenia is a thought, perception disorder, generally regarded as an illness with onset in late adolescence or early adult life with a prevalence rate of 1%. Although the long-term course of schizophrenia shows great heterogeneity among patients, a significant number of patients experience very poor outcomes, shows severe cognitive impairment that is suggestive of a progressive neurodegenerative disorder. The aim of this study is to explore the relationship between neurodegenerative process and telomere length in schizophrenic patients. The latency of P300 event-related potentials is prolonged in disorders associated with neural damage and degeneration and also becomes prolonged in the course of aging process. This study is separated as two parts: first part, using the event-related potentials P300 latency as a tool to evaluate the cognitive dysfunction and aging process in schizophrenics. One hundred and fifty three long-term hospitalization chronic schizophrenics were recruited as the experimental group of this research, including 44 male and 109 female patients with mean age of 38.4 years. These patients were divided into 2 groups according to the different responses to treatment, global assessment functional scale (GAF): 91 with good response to treatment; 62 with poor response to treatment. The normal control group included 101 normal people, male 37 and female 76, with mean age of 38.1 years. The event-related potentials was elicited by auditory oddball paradigm. The P300 latency prolonged in these two schizophrenic patients. The longest P300 latency was found in the poor response schizophrenic group. The shortest P300 latency was found in the normal group. Linear regression coefficients were computed to determine the slope of component P300 latency on age and other factors. The slope of P300 latency on age in normal control group is 1.2 ms/y. In schizophrenic groups, not only the age, but the GAF as the most contributing factors in the neurodegenerative process. Second part, the subjects were selected from part one, 48 chronic schizophrenia whose mean age was 37.9 years and 48 age-, handedness-, and gender-matched normal control subjects. The schizophrenic patients were divided into 2 groups according to the different responses to treatment: 34 with good response to treatment; 14 with poor response to treatment. The telomere length, measured by assay of terminal restriction fragments (TRFs), was determined in HinfI-digested DNA by Southern blot analysis using a (TTAGGG)4 probe. The shortest TRF length was found in the poor response schizophrenic group. There was no difference between the good response schizophrenic group and normal control group. TRF length in peripheral leukocytes obtained from normal control group decreased by approximately 89bP per year. In schizophrenic groups, the TRF length was found that not the age, but the age onset and GAF as the most contributing factors in linear regression model. This study shows that the poor response schizophrenic patients have the most rapid neurodegenerative process in P300 latency and TRF length evaluation. It implicates the homogeneous group, and can be considered as the kraepelinian schizophrenics, very poor outcome group.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xi, 94 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 78-89).

The evolution of prostate cancer from normal epithelium via the preneoplastic lesion of high-grade prostatic intraepithelial neoplasia to invasive carcinoma is characterised by a number of particular genomic abnormalities that are predominantly generated in the preneoplastic phase. Whilst there are numerous candidates for the cause of these alterations, telomere dysfunction is thought to be a major contributor. Telomeres are the terminal ends of human chromosomes, and when dysfunctional can lead to break-fusion-bridge cycles and multi-polar mitoses that generate numerical and structural chromosomal instability. The results presented reinforce the association of telomere dysfunction with the generation of certain markers of genomic instability such as abnormalities of the arms of chromosome 8. Furthermore, this work clarifies that the TMPRSSS2-ERG aberrations are not telomere related phenomena and are associated with a genomic deletion in a proportion of cases. Similarly, the PTEN microdeletions did not appear to have an association with telomere attrition. A previously unrecognised association between the telomere length in various types of prostatic epithelia and adjacent stroma is defined, suggesting evidence of a micro-environmental field effect in the generation of prostatic neoplasia. Finally, when examined retrospectively, it appears that telomere attrition, both in the HPIN epithelium and the stroma has independent prognostic value in the diagnosis of prostate cancer after a previous diagnosis of HPIN. Taken together, the research presented suggests important avenues for further research to determine the nature of barriers to the evolution of prostatic carcinogenesis such as oncogene- and telomere-induced senescence that may be exploited for therapeutic gain. These understandings may also help tailor management for prostate cancer such as risk stratification for men with HPIN and the use of targeted agents such as AKT inhibitors and telomerase inhibitors. In more advanced disease, translational application of this work has enabled a clinical trial of cytarabine in the treatment of metastatic hormone refractory prostate cancer.