Browsing by Subject "Diabetes"
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Item A Bifurcational Analysis of the Onset of Type 1 Diabetes(2018-01-01) Reddan, Adam; Peercy, Brad; Mathematics and Statistics; Mathematics, AppliedThe purpose of this paper is to combine two models of diabetes and analyze the periodic behavior and the bifurcations produced by the newly combined model. The first of these two models by Mahaffy \cite{Mahaffy2007} analyzes the onset of type 1 diabetes (T1D) at the cellular level due to an immune response, where as the second, the Topp model \cite{Topp}, analyzes the coupled dynamics between beta cell mass, insulin, and glucose. Both models include an equation for beta cell mass which is the key equation in combining the two and will enable us to look at how insulin and glucose levels change and relate to the onset of T1D. The resulting model provides a plethora of mathematically interesting properties such as various different bifurcations and bifurcation types as well as chaos. In terms of biology, we show that the combined model produces a situation in which beta cells actually recover after the initial attack on the pancreas. We are able look at the concentration of certain cell types in the blood at different stages during the onset. Our goal is to use the mathematical properties mentioned above to conclude that the combination of the Mahaffy and Topp models, and thus coupling glucose and insulin to immune cells, leads to a case of recovery of beta cells as well as forcing beta cell recovery by controlling the degradation of beta cell peptides. This exhibits the impact that certain parameter changes have on pathways to T1D. From this analysis, we can conclude that there are two types of recovery from T1D before it sets in and becomes permanent. The first is cyclic recovery in which beta cell mass, insulin concentrations, and glucose concentrations oscillate as they return to their healthy steady state values and low levels of effector T-cells remain in the blood stream but not high enough levels to induce full blown T1D. The second is noncyclic recovery in which beta cell mass, insulin concentrations, and glucose concentrations return to healthy steady state values but do not oscillate, which means that no effector T-cells remain in the blood after a certain time period.Item Survivability of Bacteria on Blood Glucose Testing Strips(2019) Nalesnik, Meghan; Health SciencesObjective: Our research focus is to determine exactly how long clinically significant organisms, Escherichia coli 0157:H7, Pseudomonas aeruginosa, methicillin resistant Staphylococcus aureus (MRSA), and vancomycin resistant Enterococcus faecalis (VRE) survive on blood glucose testing strips. Design: Four separate tubes oftrypticase soy broth (TSB) were inoculated with each of the chosen test organisms and then incubated at 3 7°C overnight. The next day they were removed from incubation to slow down their growth. To determine the number of colony forming units (CFU) in each sample, dilutions of each organism were plated onto Mueller Hinton agar. The dilution with the most reliable colony count was used to calculate the dilution needed to create a 100,000 CFU/mL of phosphate buffered saline (pH 7.2) organism load. The blood glucose testing strips were inoculated with 1 0µL of inoculate at the non-electrical end of the strip and 1 0µL of inoculate was pipetted onto the blood collection site directly for a total of 20µL. Every day thereafter, a strip corresponding to each organism was pressed to a designated section on a CHROMagar™ plate for 30 seconds and then removed in order to replicate how long a blood glucose test strip would be handled in a clinical setting. The plate was then incubated at 3 7°C for 24 hours and observed for growth. Above the strip placement site, a reference sample consisting of a pure culture of each organism was swabbed onto the agar as a positive control. The phosphate buffered saline diluent served as a negative control. Setting: This research took place in the Medical Laboratory Science Program laboratories at Salisbury University, Maryland. Results: Each organism survived as follows: Escherichia coli 0157:H7, only one colony per day for days 42-45; Pseudomonas aeruginosa, colonies were too numerous to count for the first five days and then their number greatly declined to less than five colonies until day 11; methicillin resistant Staphylococcus aureus (MRSA), colonies were too numerous to count; and vancomycin resistant Enterococcus faecalis (VRE), colonies were also too numerous to count. Conclusion: Even though the surfaces of a blood glucose strip are non-nutritive and desiccated, clinically significant organisms survive for many days, making these strips a potentially important source of infection when they become contaminated.