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DR. Tafadzwa Chihanga
Once upon a time about 12 years ago The Rotary Club of Atlantic City hosted a Youth Exchange student who turned out to be a very special Exchange student from Zimbabwe. We call her Taf. Taf's host parents were Joel and Ann Kopke. Joel and Ann had hosted students for quite a few years. Some were a challenge, but one was a very special and very smart. Joel and Ann shared hosting with Bernadette and Marty. When it was time for Taf to go home to Zimbabwe , Joel, Marty and Bernadette began to fear that this very talented young lady would land at a dead end in Zimbabwe, with no chance to further her education. The group started a movement to facilitate bringing Taf back to the USA to continue her education. Rotarian's from the AC Club, Egg Harbor City Club and many Rotarians from the district donated to the fund. I will not name any, but when you read Taf's "Front of Dissertation", you will read the names of the special people in her life changing experience. Oh, here it is:
To My Parents
"Bernadette and Uncle Bob, Anne and Joel, Marty, Cathrine and Simon for accepting all my crazy ideas and always being a safe place to land."
Bernadette and and Uncle Bob are Jennings, Anne and Joel are Kopke, Marty is Marty Wood. Catherine and Simon Chihanga (her real parents)
They say it takes a village to raise a child, she definitely had one!
I will not name any, but when you read Taf's "Front of Dissertation", you will read the names of the special people in her life changing experience. Oh, here it is:
ACKNOWLEDGEMENTS
I would like to thank my graduate school advisor, Dr. Kennedy, for the guidance and opportunity to work on various projects. I would also like to thank my committee members and collaborators at Cincinnati Children’s Hospital. To Dr. Hershberger, Dr. Brinkman and Dr. Robinson for being amazing mentors.
Thank you to my Family, the ones I picked or who picked me and the ones I was born to, for always cheering me on.
To the best examples of scientific greatness Dr. Ni and Dr. Ramelot thank you for all the lessons and patience.
To my family in Rotary, specifically those in District 7640 thank you so much for believing in me and supporting me.
And last but not least, I would like to thank all my friends especially:
Heidi Mae for all the comfort cookies and laughter filled cards
Sibu, Catherine, Tari, Prudence, Kelli, Jen, Justin, Ashley, Anushika and Rufaro for being my light in sometimes dark spaces and always making me laugh.
Theresa, Nelson, Vivian, Josephine and Max thank you for giving me a home full of laughter, warmth and love.
A DISSERTATION
Presented to the Faculty of
Miami University in partial
fulfillment of the requirements
for the degree of
Doctor of Philosophy
Department of Chemistry and Biochemistry
by
Tafadzwa Chihanga
The Graduate School
Miami University
Oxford, Ohio
2017
Dissertation Director: Michael A. Kennedy
This dissertation uses NMR metabonomics as a tool to identify metabolic changes that occur as a result of: sample processing, injury and disease. The first part of this dissertation focuses on NMR-metabonomics methods development using pancreatic cancer cell lines to investigate the influence of drying techniques and culture media on the intracellular metabolome identified. The second part uses NMR-metabonomics to identify changes in the urinary metabolome of mouse models of human disease. Chapter 1 provides background on NMR metabonomic studies that utilized immortalized cell lines, mouse model and human samples. An overall background in the NMR, statistical analysis methods and Principal Components Analysis is summarized. Chapter 2 illustrates the importance of culture media on the metabolic profile of three pancreatic cancer cell line: MiaPaCa-2, Panc-1 and AsPC-1. Though it was confirmed that culture media had a clear influence on pathway activity, there were pathways that were identified which were intrinsically different between the cell lines. Chapter 3 provides a comparison of two drying techniques, (freeze drying) lyophilization and speed vacuum, on the metabolic profile of three cell lines investigates in Chapter 2. This study highlights the importance of the drying technique and its influence on the observed metabolome. Chapter 4 describes the changes in the urine metabolome of a pancreatic cancer orthotopic model established using the MiaPaCa-2 cancer cell line. This study identified changes in the metabolome as a function of tumor growth. Chapter 5 is a study comparing the mouse urine of healthy mice and of mice with confirmed acute kidney injury (AKI). Current biomarker of AKI were used to identify disease state. The metabolic profile. Transmission and scanning electron microscopy were used to assess ultrastructural changes in kidney tissue which included a significant loss in mitochondria which significantly altered the urine metabolome. Chapter 6 investigates the urinary metabolome that emerges in a hypoxia-induced AKI model. Chapter 6 uses similar accepted diagnostic tools for AKI as in Chapter 5 which confirmed AKI in the first 24 h. This study further looked at the urinary metabolome as the mice recovered 48 h, 72 h and 7 days. Hypoxia induced AKI alone was shown to be a non-fatal injury aided by the activation of HIF-1. Chapter 7 summarizes all research and discusses possible future directions.