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Thesis (Ph.D.)--Boston University, Henry M. Goldman School of Dental Medicine. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Porphyromonas gingivalis , a Gram-negative anaerobic pathogen of periodontal diseases, requires iron in the form of heme (a term used to denote either the ferrous or ferric form of iron protoporphyrin IX) for growth. P. gingivalis is capable of utilizing a broad range of heme-containing compounds such as hemoglobin, hemoglobin-bound haptoglobin, hemin-bound hemopexin and hemin-saturated serum. Heme and hemoglobin utilization in P. gingivalis requires the participation of an outer membrane protein HmuR (heme utilization receptor), as well as cysteine proteinase gingipains (Lysine-specific gingipain Kgp and Arginine specific gingipains Rgps). However, the specific mechanisms utilized for heme acquisition are poorly understood. In this study, the role of HmuR in heme utilization was characterized in both E. coli and P. gingivalis . Molecular interaction between HmuR and hemin/hemoproteins was also characterized by construction and analysis of HmuR site-directed mutants. Our results support the direct role of HmuR in heme utilization. Hemoprotein utilization in P. gingivalis requires the participation of HmuR conserved residues. The HmuR residues 95 and 434, as well as the NPDL motif, seem to be involved in whole cell binding of hemoproteins; while the YRAP motif does not. All these residues seem essential for serum hemoprotein utilization. Analyses of HmuR by homology modeling provided a structural basis for functional analysis and supported the results from mutagenesis studies. In addition, expression of the hmuR, kgp and rgpA genes in response to different heme sources was also examined. We found that expression of the hmuR gene was negatively regulated by heme, while expression of the kgp and rgpA genes seemed to be regulated by growth phase. These different regulatory mechanisms, as well as the coordinate expression between HmuR and gingipains, indicate a complementary regulation mechanism for optimal heme utilization in P. gingivalis. / 2031-01-01

The aim of this Master's thesis is to process a business plan for dental clinic Easydent s.r.o., which decided to expand and set up a new dental practice in the city centre. The theoretical part presents the business plan in general terms, with a particular focus on the definition, the reasons for its formulation and the form and structure of this document. Moreover, this part also includes the criteria of the investment decision-making and static as well as dynamic methods of the investment evaluation. Afterwards, the specifics of doing business in healthcare are presented with special emphasis on dental medicine and the differences from other businesses. The practical part presents the business plan for setting up the new dental practise especially with focus on economic aspects of the project as well as on general feasibility. To conclude, I found that the investment according to the net present value is profitable and I recommend setting up a new dental practice in the city centre.

In spite of electrogustometry having been in existence since the 1930s, there is no state of the art instrument to assess the electrogustometric threshold. A state of the art electrogustometer has been designed and constructed and tested for reliability and repeatability. This is based on embedded digital technology and is a semi-automatic, battery-powered portable instrument. Physical factors such as electrode area and stimulus duration affect the taste threshold but there are no recommended standards for these factors. Studies have been conducted to ascertain a recommended standard – a circular stainless steel electrode area of 28.5 mm2 and a stimulus duration of 2 seconds. While performing the test-retest assessment of the Sussex Electrogustometer, the new instrument, an anomaly was observed. Upon further investigation it was concluded that it was caused by alcohol consumed by a subject prior to the retest. Elaborate experiments were designed with the help of a neurologist and psychologist to understand the immediate effect of alcohol on taste for non-alcoholics. The results indicated an immediate improvement of taste for lower concentrations of alcohol and a delayed improvement for higher concentration. The studies were extended to understand the immediate effect of anaesthetics and smoking on taste which showed that taste deteriorated as expected. The new machine was used successfully in the clinical environment by local doctors and a report on their findings has also been included within this thesis.