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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Time-Resolved Femtosecond Laser Spectroscopic Study of the Reaction

Kalantari, Saeed 14 August 2007 (has links)
Being currently the second and potentially becoming the first cause of death in North America, cancer has been the focus of researchers from various areas of science. Chemotherapy is one of the leading treatment options for treating various types of cancer, particularly advanced cancers. Among different chemotherapeutic drugs currently used against cancer, cisplatin (CDDP) is considered as one of the most effective and widely used. Despite being the most successful drug in cancer chemotherapy, cisplatin has some shortcomings that restrict it from being more widely used. More than three decades of intensive research has not yet clearly explained why these shortcomings are associated with cisplatin treatment. Using the advanced “Pump-Probe Femtosecond Time-Resolved Transient Absorption Laser Spectroscopy” technique to study the reaction dynamics of cisplatin at the molecular level, we discovered new findings that make a profound contribution to our understanding of the mechanism of activity of CDDP as a very widely used and effective anticancer drug. By observing the reaction dynamics of cisplatin both in its reaction with electrons in water, and with all four DNA bases, in real time, we shed new light on the issues that have long been elusive for the last three decades. In addition to these two main research goals, we utilized the same methodology to examine the reaction dynamics of transplatin, which currently is not a clinically effective drug, despite being an isomer of cisplatin. In this part we mainly focused on examining the molecular reaction dynamics of transplatin photoactivation caused by UV irradiation. Here, we studied the transplatin reaction with electrons in water as well as with four DNA bases. Results obtained in this thesis work clearly reveal the mechanism underlying the cytotoxicity enhancement of this molecule after it is irradiated by UV radiation. The data obtained by our experiments provide a mechanistic understanding of this cytotoxicity enhancement at the molecular level. As the last goal in our research, we compared the explored reaction dynamics of cisplatin with its clinically ineffective trans isomer, transplatin. We believe that our understanding of one of these isomers, would also contribute to understanding of the other. The methodology we used to examine transplatin was the same as what we used for cisplatin. First, we monitored the possible reactions of transplatin with prehydrated electrons in water. After this, the dynamics of transplatin’s reactions with DNA bases were examined. For the first time, we directly observed the reactions of cisplatin and discovered that its extremely high reactivity with prehydrated electrons happens in an ultrafast process. We also showed the order of reactivity of all four DNA bases with cisplatin and transplatin to be G > A > C > T. Finally, in comparing cis and trans isomers of DDP, we discovered cisplatin to be about 50% more reactive, suggesting why it is much more cytotoxic. In all of these investigations we obtained promising results that revolutionize our understanding of the mechanism of action of cisplatin as a very important drug in current cancer chemotherapy.
12

Investigation of the effects and mechanisms of action of a novel vitamin E derivative (alpha-TEA) in combination with Cisplatin, and the resulting reversal of drug resistance in a Cisplatin-resistant human ovarian cancer cell line, Cp70

Anderson, Kristen Marie. January 2003 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available from UMI Company.
13

Characterization of the N-terminus of human copper transporter (HCTR1)and mechanism comparison between the cellular uptake of Cu andcisplatin via HCTR1

Du, Xiubo., 都秀波. January 2011 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
14

Investigating the mechanism of action of the chemotherapeutic agent, cisplatin: drug-DNA interactions in reconstituted chromatin and human gene expression profiling

Galea, Anne Marie, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW January 2006 (has links)
The DNA-damaging compound, cisplatin (cis-diamminedichloridoplatinum (II)), is a highly successful anti-tumour agent widely used in the treatment of a range of human cancers. Despite the clinical efficacy of cisplatin, its curative potential is largely restricted by the occurrence of drug resistance and several dose-limiting toxic side effects. Attempts to ameliorate these deficiencies have met with limited success. However, it is ultimately hoped that such efforts will benefit from a more comprehensive understanding of the mechanism by which cisplatin elicits tumourspecific cytotoxicity. The overall aim of this project was to further elucidate the mechanism of action of cisplatin. For this purpose, different experimental approaches were employed to examine the interaction of cisplatin with DNA, and the drug???s effect on human gene expression. Firstly, chromatin structures native to DNA in human cells were simulated in vitro via reconstitution techniques. Their effect on cisplatin-mediated DNA damage could then be evaluated. Various cisplatin analogues and other DNA-damaging compounds were also investigated in this model system. Secondly, the transcriptional response of human cells to cisplatin treatment was analysed using microarrays and gene expression profiling techniques. Transcript profiles compiled for cisplatin and its clinically ineffective isomer, transplatin, were compared to establish a possible relationship between compound-specific responses and therapeutic efficiency. To assess the relative influence of individual chromatin elements on cisplatin- DNA interactions, the first part of this study employed the octamer transfer method of nucleosome reconstitution to create a defined experimental construct. Standard footprinting techniques allowed the precise location of two positioned nucleosomes to be established with respect to the DNA sequence. The construct was then subjected to drug treatment and the resulting DNA damage was quantitatively analysed using a Taq DNA polymerase stop assay. At sites of damage, densitometric comparisons between purified and reconstituted DNA were used to evaluate the influence of nucleosomal core proteins on specific drug-DNA interactions. For cisplatin and most of the other DNAdamaging agents studied, this method revealed regions of the construct that were relatively protected from drug-induced damage. These regions corresponded to the sites of the positioned nucleosome cores and indicated that the preferred site of DNA binding for these compounds was in the linker region of the construct. Statistical analyses confirmed the significant level of damage protection conferred by the nucleosome cores and exposed subtle differences between the agents examined. Most prominent among the trends observed, was the negative correlation between compound size and the relative propensity for damaging nucleosomal core DNA. Larger compounds generally displayed a greater tendency to target the linker region of the nucleosomal DNA. In contrast, the access of smaller molecules was not impeded as significantly. In the second stage of the project, the effect of cisplatin on human gene expression levels was described using 19000-gene microarrays and transcription profiling methods. In cultured human cells, cisplatin treatment was shown to significantly up- and down-regulate consistent subsets of genes. Many of these genes responded similarly to treatment with transplatin, the therapeutically inactive isomer of cisplatin. However, a smaller proportion of these transcripts underwent differential expression changes in response to the two isomers. Some of these genes may constitute part of the DNA damage response induced by cisplatin that is critical for its anti-tumour activity. Ultimately, the identification of gene expression responses unique to clinically active compounds, like cisplatin, could thus greatly benefit the design and development of improved chemotherapeutics.
15

Investigating the mechanism of action of the chemotherapeutic agent, cisplatin: drug-DNA interactions in reconstituted chromatin and human gene expression profiling

Galea, Anne Marie, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW January 2006 (has links)
The DNA-damaging compound, cisplatin (cis-diamminedichloridoplatinum (II)), is a highly successful anti-tumour agent widely used in the treatment of a range of human cancers. Despite the clinical efficacy of cisplatin, its curative potential is largely restricted by the occurrence of drug resistance and several dose-limiting toxic side effects. Attempts to ameliorate these deficiencies have met with limited success. However, it is ultimately hoped that such efforts will benefit from a more comprehensive understanding of the mechanism by which cisplatin elicits tumourspecific cytotoxicity. The overall aim of this project was to further elucidate the mechanism of action of cisplatin. For this purpose, different experimental approaches were employed to examine the interaction of cisplatin with DNA, and the drug???s effect on human gene expression. Firstly, chromatin structures native to DNA in human cells were simulated in vitro via reconstitution techniques. Their effect on cisplatin-mediated DNA damage could then be evaluated. Various cisplatin analogues and other DNA-damaging compounds were also investigated in this model system. Secondly, the transcriptional response of human cells to cisplatin treatment was analysed using microarrays and gene expression profiling techniques. Transcript profiles compiled for cisplatin and its clinically ineffective isomer, transplatin, were compared to establish a possible relationship between compound-specific responses and therapeutic efficiency. To assess the relative influence of individual chromatin elements on cisplatin- DNA interactions, the first part of this study employed the octamer transfer method of nucleosome reconstitution to create a defined experimental construct. Standard footprinting techniques allowed the precise location of two positioned nucleosomes to be established with respect to the DNA sequence. The construct was then subjected to drug treatment and the resulting DNA damage was quantitatively analysed using a Taq DNA polymerase stop assay. At sites of damage, densitometric comparisons between purified and reconstituted DNA were used to evaluate the influence of nucleosomal core proteins on specific drug-DNA interactions. For cisplatin and most of the other DNAdamaging agents studied, this method revealed regions of the construct that were relatively protected from drug-induced damage. These regions corresponded to the sites of the positioned nucleosome cores and indicated that the preferred site of DNA binding for these compounds was in the linker region of the construct. Statistical analyses confirmed the significant level of damage protection conferred by the nucleosome cores and exposed subtle differences between the agents examined. Most prominent among the trends observed, was the negative correlation between compound size and the relative propensity for damaging nucleosomal core DNA. Larger compounds generally displayed a greater tendency to target the linker region of the nucleosomal DNA. In contrast, the access of smaller molecules was not impeded as significantly. In the second stage of the project, the effect of cisplatin on human gene expression levels was described using 19000-gene microarrays and transcription profiling methods. In cultured human cells, cisplatin treatment was shown to significantly up- and down-regulate consistent subsets of genes. Many of these genes responded similarly to treatment with transplatin, the therapeutically inactive isomer of cisplatin. However, a smaller proportion of these transcripts underwent differential expression changes in response to the two isomers. Some of these genes may constitute part of the DNA damage response induced by cisplatin that is critical for its anti-tumour activity. Ultimately, the identification of gene expression responses unique to clinically active compounds, like cisplatin, could thus greatly benefit the design and development of improved chemotherapeutics.
16

Investigating the mechanism of action of the chemotherapeutic agent, cisplatin: drug-DNA interactions in reconstituted chromatin and human gene expression profiling

Galea, Anne Marie, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW January 2006 (has links)
The DNA-damaging compound, cisplatin (cis-diamminedichloridoplatinum (II)), is a highly successful anti-tumour agent widely used in the treatment of a range of human cancers. Despite the clinical efficacy of cisplatin, its curative potential is largely restricted by the occurrence of drug resistance and several dose-limiting toxic side effects. Attempts to ameliorate these deficiencies have met with limited success. However, it is ultimately hoped that such efforts will benefit from a more comprehensive understanding of the mechanism by which cisplatin elicits tumourspecific cytotoxicity. The overall aim of this project was to further elucidate the mechanism of action of cisplatin. For this purpose, different experimental approaches were employed to examine the interaction of cisplatin with DNA, and the drug???s effect on human gene expression. Firstly, chromatin structures native to DNA in human cells were simulated in vitro via reconstitution techniques. Their effect on cisplatin-mediated DNA damage could then be evaluated. Various cisplatin analogues and other DNA-damaging compounds were also investigated in this model system. Secondly, the transcriptional response of human cells to cisplatin treatment was analysed using microarrays and gene expression profiling techniques. Transcript profiles compiled for cisplatin and its clinically ineffective isomer, transplatin, were compared to establish a possible relationship between compound-specific responses and therapeutic efficiency. To assess the relative influence of individual chromatin elements on cisplatin- DNA interactions, the first part of this study employed the octamer transfer method of nucleosome reconstitution to create a defined experimental construct. Standard footprinting techniques allowed the precise location of two positioned nucleosomes to be established with respect to the DNA sequence. The construct was then subjected to drug treatment and the resulting DNA damage was quantitatively analysed using a Taq DNA polymerase stop assay. At sites of damage, densitometric comparisons between purified and reconstituted DNA were used to evaluate the influence of nucleosomal core proteins on specific drug-DNA interactions. For cisplatin and most of the other DNAdamaging agents studied, this method revealed regions of the construct that were relatively protected from drug-induced damage. These regions corresponded to the sites of the positioned nucleosome cores and indicated that the preferred site of DNA binding for these compounds was in the linker region of the construct. Statistical analyses confirmed the significant level of damage protection conferred by the nucleosome cores and exposed subtle differences between the agents examined. Most prominent among the trends observed, was the negative correlation between compound size and the relative propensity for damaging nucleosomal core DNA. Larger compounds generally displayed a greater tendency to target the linker region of the nucleosomal DNA. In contrast, the access of smaller molecules was not impeded as significantly. In the second stage of the project, the effect of cisplatin on human gene expression levels was described using 19000-gene microarrays and transcription profiling methods. In cultured human cells, cisplatin treatment was shown to significantly up- and down-regulate consistent subsets of genes. Many of these genes responded similarly to treatment with transplatin, the therapeutically inactive isomer of cisplatin. However, a smaller proportion of these transcripts underwent differential expression changes in response to the two isomers. Some of these genes may constitute part of the DNA damage response induced by cisplatin that is critical for its anti-tumour activity. Ultimately, the identification of gene expression responses unique to clinically active compounds, like cisplatin, could thus greatly benefit the design and development of improved chemotherapeutics.
17

Deterministic modelling of kinetics and radiobiology of radiation-cisplatin interaction in the treatment of head and neck cancers /

Marcu, Loredana Gabriela. January 2004 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, Discipline of Physics, 2005. / Includes bibliographical references. Also available electronically.
18

Effekte von Hyperthermie in Kombination mit Bestrahlung und Cisplatin auf humane Karzinomzellen in einem 3D-Perfusionssystem /

Wahl, Ulrich. January 1998 (has links) (PDF)
Freie Univ., Diss.--Berlin, 1998.
19

Comparison of two saline loading protocols for preventing nephrotoxicosis associated with high-dose cisplatin /

Fallin, Edward Alton, January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 81-86). Also available via the Internet.
20

Regulation of ceramide synthase 1 in cellular stress response

Sridevi, Priya. Alexander, Hannah Ben-Ze'ev. Alexander, Stephen, January 2008 (has links)
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 25, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Stephen Alexander and Dr. Hannah Alexander. Vita. Includes bibliographical references.

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