The Unseen Life of Tom Hill

The office that Dr. Thomas Hill works in is large, complete with a wood paneled desk, wall-to-wall bookshelf and conference table. Iowa State University’s vice president of student affairs uses all this space, bouncing back and forth from desk to conference table—whichever is the least covered in stacks of paper at the time. His day is filled with meetings and phone calls, whether it’s a meeting to advise a group of graduate students working on a project or taking a call from an old Olympic teammate who’s looking to get one of his athletes a scholarship

Microchemostat technologies for characterization of efflux pumps associated with multidrug resistance in mycobacterium tuberculosis.

Doctor of Philosophy in Medical Microbiology. University of KwaZulu-Natal, Durban 2016.Abstract available in PDF file

The effects of Tulbaghia violacea leaf, bulb and stalk extracts on Jurkat cells.

Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2012.Studies have shown that the traditional healers have used Tulbaghia violacea (TV) (also known as ‘wild garlic’) for the treatment of a number of ailments including fever, tuberculosis, stomach problems, and oesophageal cancer. However, little is known with regards to the anticancer and antiproliferative properties of this plant. Therefore, this study investigated the effects of TV and domesticated garlic extracts on Jurkat cells, in order to determine whether or not these extracts possess anti-proliferative properties. Cultured Jurkat cells were treated with IC50 concentrations of garlic (14μg/ml), TV leaf (256μg/ml), TV bulb (225μg/ml) and TV stalk (216μg/ml) extracts as determined by the methylthiazol tetrazolium assay. Free radical production was measured using the thiobarbituric acid reactive substance (TBARS) and nitric oxide (NO) assays, while glutathione (GSH) concentration was measured using the GSH-Glo™ assay. The apoptosis inducing properties of each extract were measured using flow cytometry (Annexin V- Fluos and JC-1 assays) and luminometry (caspases 3/7, 8, 9 and ATP). Western blots were run to determine protein expression, while comet and DNA fragmentation assays were used to determine the level of DNA damage induced. Wild and domesticated garlic extracts induced a significant increase in malondialdehyde concentration ([MDA]), with TV bulb extract inducing the highest concentration (p<0.0001). A significant increase in NO concentration was observed in the bulb (p<0.0001) and stalk (p<0.001) extracts, and leaf (p<0.05) and stalk (p<0.05) TV extracts significantly increasing GSH concentration. The longest comet tails were observed in TV bulb extracts (p<0.0001) and comprised mainly of single strand breaks, while the comets induced following garlic exposure contained double strand breaks. All extracts, except TV leaf, increased the percentage of cells undergoing apoptosis. Tulbaghia violacea leaf induced a significant (p<0.0001) increase in percentage of cells undergoing necrosis, whereas TV bulb resulted in a significant (p<0.0001) decrease. All TV extracts induced caspase 3/7 and 9 activity, with the most significant increase in caspase 9 activity observed for TV leaf and bulb. No significant change in caspase 3/7 activity was evident for domesticated garlic. Cleavage of PARP and expression of NF B and HSP 70 occured for all extracts. However, HSP 70 was not differentially expressed. Exposure to wild and domesticated garlic extracts induced peroxidative lipid and DNA damage within the cells, indicating oxidative stress. This damage occurred in conjunction with increased percentage of cells undergoing apoptosis and expression of caspase 3/7. Therefore, these findings suggest that TV is inducing cell death through apoptosis in Jurkat cells using a number of mechanisms, including the induction of oxidative stress. This is of clinical significance, as cell death through apoptosis is the preferred method of action for anti-cancer drugs

Host immunity increases Mycobacterium tuberculosis reliance on cytochrome bd oxidase [preprint]

In order to sustain a persistent infection, Mycobacterium tuberculosis (Mtb) must adapt to a changing environment that is shaped by the developing immune response. This necessity to adapt is evident in the flexibility of many aspects of Mtb metabolism, including a respiratory chain that consists of two distinct terminal cytochrome oxidase complexes. Under the conditions tested thus far, the bc1/aa3 complex appears to play a dominant role, while the alternative bd oxidase is largely redundant. However, presence of two terminal oxidases in this obligate pathogen implies that respiratory requirements might change during infection. We report that the cytochrome bd oxidase is specifically required for resisting the adaptive immune response. While the bd oxidase was dispensable for growth in resting macrophages and the establishment of infection in mice, this complex was necessary for optimal fitness after the initiation of adaptive immunity. This requirement was dependent on lymphocyte-derived interferon gamma (IFNγ), but did not involve nitrogen and oxygen radicals that are known to inhibit respiration in other contexts. Instead, we found that ΔcydA mutants were hypersusceptible to the low pH encountered in IFNγ-activated macrophages. Unlike wild type Mtb, cytochrome bd-deficient bacteria were unable to sustain a maximal oxygen consumption rate (OCR) at low pH, indicating that the remaining cytochrome bc1/aa3 complex is preferentially inhibited under acidic conditions. Consistent with this model, the potency of the cytochrome bc1/aa3 inhibitor, Q203, is dramatically enhanced at low pH. This work identifies a critical interaction between host immunity and pathogen respiration that influences both the progression of the infection and the efficacy of potential new TB drugs

Host immunity increases Mycobacterium tuberculosis reliance on cytochrome bd oxidase

In order to sustain a persistent infection, Mycobacterium tuberculosis (Mtb) must adapt to a changing environment that is shaped by the developing immune response. This necessity to adapt is evident in the flexibility of many aspects of Mtb metabolism, including a respiratory chain that consists of two distinct terminal cytochrome oxidase complexes. Under the conditions tested thus far, the bc1/aa3 complex appears to play a dominant role, while the alternative bd oxidase is largely redundant. However, the presence of two terminal oxidases in this obligate pathogen implies that respiratory requirements might change during infection. We report that the cytochrome bd oxidase is specifically required for resisting the adaptive immune response. While the bd oxidase was dispensable for growth in resting macrophages and the establishment of infection in mice, this complex was necessary for optimal fitness after the initiation of adaptive immunity. This requirement was dependent on lymphocyte-derived interferon gamma (IFNgamma), but did not involve nitrogen and oxygen radicals that are known to inhibit respiration in other contexts. Instead, we found that DeltacydA mutants were hypersusceptible to the low pH encountered in IFNgamma-activated macrophages. Unlike wild type Mtb, cytochrome bd-deficient bacteria were unable to sustain a maximal oxygen consumption rate (OCR) at low pH, indicating that the remaining cytochrome bc1/aa3 complex is preferentially inhibited under acidic conditions. Consistent with this model, the potency of the cytochrome bc1/aa3 inhibitor, Q203, is dramatically enhanced at low pH. This work identifies a critical interaction between host immunity and pathogen respiration that influences both the progression of the infection and the efficacy of potential new TB drugs

Evaluating the feasibility of implementing a Telesleep pilot program using two-tiered external facilitation

Background: Obstructive sleep apnea (OSA) can negatively impact patients' health status and outcomes. Positive airway pressure (PAP) reverses airway obstruction and may reduce the risk of adverse outcomes. Remote monitoring of PAP (as opposed to in-person visits) may improve access to sleep medicine services. This study aimed to evaluate the feasibility of implementing a clinical program that delivers treatment for OSA through PAP remote monitoring using external facilitation as an implementation strategy. Methods: Participants included patients with OSA at a Veteran Affairs Medical Center (VAMC). PAP adherence and clinical disease severity on treatment (measured by the apnea hypopnea index [AHI]) were the preliminary effectiveness outcomes across two delivery models: usual care (in-person) and Telehealth nurse-delivered remote monitoring. We also assessed visit duration and travel distance. A prospective, mixed-methods evaluation examined the two-tiered external facilitation implementation strategy. Results: The pilot project included N = 52 usual care patients and N = 38 Telehealth nurse-delivered remote monitoring patients. PAP adherence and disease severity were similar across the delivery modalities. However, remote monitoring visits were 50% shorter than in-person visits and saved a mean of 72 miles of travel (median = 45.6, SD = 59.0, mode = 17.8, range 5.4-220). A total of 62 interviews were conducted during implementation with a purposive sample of 12 clinical staff involved in program implementation. Weekly external facilitation delivered to both front-line staff and supervisory physicians was necessary to ensure patient enrollment and treatment. Synchronized, "two-tiered" facilitation at the executive and coordinator levels proved crucial to developing the clinical and administrative infrastructure to support a PAP remote monitoring program and to overcome implementation barriers. Conclusions: Remote PAP monitoring had similar efficacy to in-person PAP services in this Veteran population. Although external facilitation is a widely-recognized implementation strategy in quality improvement projects, less is known about how multiple facilitators work together to help implement complex programs. Two-tiered facilitation offers a model well-suited to programs where innovations span disciplines, disrupt professional hierarchies (such as those between service chiefs, clinicians, and technicians) and bring together providers who do not know each other, yet must collaborate to improve access to care

The Unseen Life of Tom Hill

The office that Dr. Thomas Hill works in is large, complete with a wood paneled desk, wall-to-wall bookshelf and conference table. Iowa State University’s vice president of student affairs uses all this space, bouncing back and forth from desk to conference table—whichever is the least covered in stacks of paper at the time. His day is filled with meetings and phone calls, whether it’s a meeting to advise a group of graduate students working on a project or taking a call from an old Olympic teammate who’s looking to get one of his athletes a scholarship.</p