Cancer is a leading cause of mortality worldwide, and the number of new cases is projected to reach 22 million in the next two decades. Surgical resection of tissues is a standard of care for treatment of a variety of cancer patients. For the prostate, surgically removed tissues usually undergo a process of bread-loafing (cutting into 0.5-1.0 cm thickness), chemical fixation, embedding in paraffin (wax), sectioning (5-10 μm thick), staining, slide mounting and finally microscopic examination to determine whether all tumor growths have been excised. The procedure is labor-intensive, time-consuming and expensive. In addition, the majority of the prostate specimens are normal tissues that do not require detailed microscopic examination. These factors reveal the need to significantly accelerate the screening process and increase the efficient use of healthcare resources. Therefore, to reduce unnecessary processing time and costs, we proposed a fast and inexpensive imaging system to screen the surface of thick tissues for abnormality, before full histological processing. This system was designed to enable a wide imaging area and integrate deconvolution algorithms, which achieve high contrast and resolution. More specifically, the project was carried out in three phases: 1) design, construction, and optimization of a fluorescence microscope; 2) system calibration and optimization of deconvolution algorithms; and 3) system validation using fresh human tissues. The system is capable of generating a 1 x 1 cm² image in a few minutes with 4 nm resolution. Success of such a system will facilitate clinical translation and increase efficiency of histopathological procedures, which are beneficial to both patients and healthcare providers.

Macrophages are cells of the immune system that play key roles in surveillance, destruction of pathogens, and tissue repair. In the context of cancer, macrophages can infiltrate solid tumors and adopt an anti-inflammatory profile resembling that of the “M2” macrophage subclass. These M2-like tumor-associated macrophages (TAMs) promote tumor growth and metastasis by suppressing the immune response. Therefore, selective destruction of TAMs using a biomolecule that targets and binds to TAMs may have therapeutic benefit in cancer. We have previously identified a novel peptide, M2pep, that selectively binds to M2 macrophages over other immune system cells. In other experiments, a specific pattern of amino acids, named the M2pep motif, was observed to be critical for peptide binding to TAMs. This project seeks to improve M2pep binding and selectivity to TAMs by constructing and screening a library of peptides containing the M2pep motif for binding to M2 macrophages. The library was constructed by genetically engineering bacteriophages to display all possible peptides containing the M2pep motif. This was achieved by: (1) designing DNA sequences encoding for peptides with certain amino acid positions “fixed” with the M2pep motif, and the other positions randomized; (2) inserting these sequences into bacteriophage DNA; and (3) incorporating the engineered DNA into bacteria to generate bacteriophages that display the peptide library on their outer surface. Then, the peptide library was screened for binding to M2 macrophages, and the peptides that bound were sequenced. Several candidates were evaluated for M2 macrophage-binding and compared with M2pep to identify sequences with improved binding and selectivity. This method of peptide library construction and screening using a bacteriophage platform can be a powerful tool for future drug development, and enable further refinement of binding molecules with established binding motifs.

Cone-beam computed tomography (CBCT) has been one of the newest innovative technologies introduced in the field of dentistry, and its role in diagnostic imaging has been greatly beneficial for patients in need of various treatment. The goal of this study is to utilize CBCT to investigate the effects of experimental periodontitis on molar roots and alveolar bone in a pig model by taking quantitative measurements from 3D models. Four normal pigs and eight with experimental periodontitis pigs were included in this study. Experimental periodontitis was induced by periodic inoculation with 4 types of periodontal bacteria, along with the suture ligature around the upper third deciduous molar for 8 weeks. Two sets of CBCT were taken for each experimental pig before and after the induction of periodontitis, but one set for control pigs. A custom-made seat was placed on the CBCT chair for CBCT scanning while the pig was intubated with 3% isoflurane. Obtained CBCT images were then used to create 3D models using the software ITK-Snap with the aid of Invivo5. Models were standardized by the region of interest selected for segmentation. Volumetric measurements were taken in the software. The volumes of molar roots and alveolar bone were then compared in the experimental and control pigs before and after the induction of periodontitis. The expected results should show significant volumetric reduction in the alveolar bone of the experimental pigs as compared with controls. Further in the project, the expected results should show that there is significant reduction in the volume of the roots as well. Understanding the use of CBCT and its role in 3D modeling and quantitative measurement will contribute cutting-edge treatment planning and diagnostic methodologies for all dental practitioners. 

Periodontitis is a serious infection that damages both soft (gingiva and periodontal ligaments-PDL) and hard tissues (dental cementum and alveolar bone) of the periodontium. Mineralization is an essential dynamic process for development and maintenance of the periodontium. The current study focuses on how mineralization of alveolar bone and the attachments of PDL are affected by experimental periodontitis in a pig model. Eight three-month-old pigs were periodically inoculated with 4 types of periodontal bacteria, along with a ligature around the last maxillary deciduous premolar for 8 weeks to induce periodontitis. Another group of 7 pigs without the ligatures and bacterial inoculations were taken as control. Bone labeling dyes, calcein and alizarin, were injected intraperitoneally 7 and 2 days respectively before euthanasia. The harvested upper molar blocks were embedded in micro-bed resin and successive sections were taken at 30μm thickness coronally. Three sections that contained the most intact mesial and distal roots of the target molar were selected and examined under epifluorescence. The interlabel distance between two vital markers at the surfaces of alveolar socket and trabeculae, cementum, and the attachment of PDL fiber bundles were measured, and the mineral apposition rates (MAR) were calculated. Preliminary results indicate that, as compared with control pigs, periodontitis pigs showed reduced MAR in the trabecular structures, more significantly in the regions underneath the molar furcation. The reduced MAR was also seen in the alveolar ridges in the periodontitis pigs but was not as significant as the region under the furcation. More data analysis is currently underway. These results suggest that experimental periodontitis may slow down periodontal mineralization in young growing pigs, in which alveolar bone underneath the root furcation and the cortical layer of the socket are mostly affected.