Approximately 1 million Americans live with a lower-limb amputation and this number is increasing. During both the postoperative recovery period (up to 18 months) and the subsequent period patients undergo substantial changes in the volume and shape of their residual limb. Therefore, both the fit and comfort of their prosthetic are compromised. Edema, gait instability and skin irritation are often severe consequences. Patients often use socks, pads and fluid-filled bladders to compensate for these changes in volume. I am currently investigating the fluctuations in the volume of the residual limb of below-the-knee (trans-tibital) amputees. The goal is to identify patterns in the volume fluctuations over the course of the day. We have created sock logs on which patients record the changes in their sock ply during the day. Our goal is to provide practitioners, patients, and industry with insight into how often and when patients change their sock ply. We hope, with this knowledge, to propose more automated solutions for patients to manage their residual limb volume. Automation is needed because many patients elect not to change sock ply even though they need to so as to maintain a proper prosthetic fit. Similarly, our research is also focused on investigating the correlation between limb volume changes and the need for a new socket. With this data, we hope to establish a relationship between the changes in sock ply and the time at which a new prosthetic socket is needed. We predict that we will be able to foresee when a patient requires a new socket based on changes in their sock ply. With this knowledge, the information will be shared with practitioners with an expectation that it will allow them to change their daily practices to recognize the need for a new socket.

The purpose of this research is to gain insight into prosthetic sock thickness trends of multiple sock stacks. For amputee patients, stacked sock combinations are necessary to accommodate volume change of the residual limb in the short and long term. The thickness of these stacks is quantified by the total number of ply. For example, a 1-Ply sock and a 3-Ply sock make a 4-Ply “stack.” However, with this method of measurement, total sock thickness depends on how many socks are worn. The focus of this test is to evaluate existing standards by comparing the thickness of multiple socks to a single sock of the same total ply. The results from this research should provide useful information to prosthetists fitting patients with prosthetic limbs. As the residual limb matures after amputation and swelling decreases, there is a reduction in volume and a change in shape. From the first prosthesis, the practitioner optimizes the fit with the expectation of the residual limb size decreasing. The practitioner advises the patient to add socks to take up space when the residual limb feels loose in the socket. By adding socks, the patient can maintain a proper fit, and the practitioner can track limb change and socket modifications so as to appropriately time fabrication of a new socket. The present research brings quantitative information about sock thickness, both for single socks and for stacks of socks, to clinical care. This quantification should help the practitioner determine just how much larger the socket is than the patient’s residual limb, and should help guide design of a new socket. This research collected in the present study may also facilitate documentation to justify the need for a new socket.

Multiple Sclerosis is a disease characterized by inflammation and demyelination in the central nervous system. Experimental Autoimmune Encephalomyelitis (EAE) is a mouse model used to study MS. Previous studies have shown that EAE can be induced by helper T cells of both the Th17 (IL-17 producing) and Th1 (IFNg-producing) lineages. In classic EAE induced by Th1 cells, inflammation is observed predominantly in the spinal cord, however in our model of atypical EAE, induced by transfer of Th17-skewed cells, inflammation is observed in both the brain and spinal cord. This atypical model is closer to the disease course of MS in humans, because only rarely do MS patients have spinal cord inflammation without accompanying brain inflammation. Using mice that lack IL-17RA, a protein required for IL-17 signal transduction, we can study the mechanism of IL-17-induced inflammation in the brain versus the spinal cord. In our model we have shown that IL-17 promotes neutrophil recruitment to the brain, but is not required for neutrophil recruitment to the spinal cord. The presence of neutrophils in the spinal cord in IL-17 receptor knockout mice suggests some other mechanism must be used to recruit neutrophils in the spinal cord. Using RT-PCR we have been looking at the role of other factors (IFN-g, CXCL5, CXCL2, CXCL1, GMCFS, and IL-1b) in recruiting neutrophils in spinal cord independent of IL-17.

The field of gene therapy relies on vehicles that can introduce exogenous genetic material into target cells in order to affect the production of a desired therapeutic protein. Viruses have long been used as delivery vehicles, but concerns over immunogenicity have fueled efforts to develop alternative nonviral delivery vehicles. Current polycationic polymers used in gene delivery methods generally exhibit poor transfection efficiencies and also dose-dependent cell toxicity. This project seeks to address these parameters through the synthesis of a novel copolymer of 2-hydroxypropyl methacrylate (HPMA) and a methacryated oligoarginine peptide (MaAhxR10). In phase one, the HPMA-oligoarginine copolymer was synthesized and tested for basic functionality. Transfections of HeLa cell populations demonstrated that the transfection capabilities of this polymer were comparable to those of the oligolysine standard, but the toxicity was significantly enhanced. Phase two consisted of modifying the peptide with neutral amino acid residues (such as glycine) to reduce the charge density of the polycationic peptides. Further, a more efficient approach to preparing arginine peptides was developed by chemically guanidinylating lysine residues. This approach was used to generate a lysine and a homoarginine version of each polymer. The resulting copolymers were tested for transfection efficiency and cell toxicity in cultured mammalian cells. Copolymers made from the resulting ‘spaced’ peptides (MaAhx(GK)5 and MaAhx(GhR)5) demonstrated reduced cytotoxicity compared the MaAhxR10 and PEI standards, but were still comparable in transfection efficiency to the oligolysine standard. While the delivery vehicle has not performed as expected, the project may have revealed a relationship between charge density (and therefore accessibility of charge) and cytotoxicity. The next step will be to generate another panel of polymers, this time with even more spacing between positive charge residues. This will allow for the identification of a correlation between charge density and cytotoxicity.

Routine ingestion of, and contact with, myriad chemical compounds in our environment impacts all aspects of human health, from psychiatric to oncological to acute and chronic toxicities. However, health outcomes resulting from exposure events are strongly influenced by genetic variability present in genes underlying pertinent metabolic pathways. There are four genes that have been identified in the literature as playing crucial roles in multiple and interrelated biochemical pathways, and which may have broad implications for human health. These genes include DRD4, which codes for the dopamine D4 receptor and has been linked to numerous neurological conditions including addictions, schizophrenia, bipolar disorder, and Parkinson’s disease; 5-HTTLPR, the serotonin-transporter-linked region that codes for the serotonin receptor and may be involved in a host of behaviors including affective disorders and addictions; CYP2E1, a member of the cytochrome P450 family involved with the metabolism of many endogenous and exogenous chemicals including ethanol; and GSTT1, which is involved with the metabolism of toxic compounds including many carcinogens. In order to offer an accessible advanced preventative health screening tool to patients addressing numerous potential conditions, we attempted to implement a multiplexed polymerase chain reaction that would allow us to simultaneously assay these four genetic variants. We were able to combine the GSTT1 and CYP2E1 assays into a single reaction, however we were unable to find compatible reaction conditions for 5-HTTLPR and DRD4 either together or with GSTT1 and CYP2E1.