Student-Centered Rehabilitation Medicine Research Elective

Purpose: To provide an opportunity for medical students to participate in rehabilitation research and allows the investigator to develop a database of the characteristics of the medical students choosing this elective. [See PDF for complete abstract]

Molluscan memory of injury: evolutionary insights into chronic pain and neurological disorders.

Molluscan preparations have yielded seminal discoveries in neuroscience, but the experimental advantages of this group have not, until now, been complemented by adequate molecular or genomic information for comparisons to genetically defined model organisms in other phyla. The recent sequencing of the transcriptome and genome of Aplysia californica, however, will enable extensive comparative studies at the molecular level. Among other benefits, this will bring the power of individually identifiable and manipulable neurons to bear upon questions of cellular function for evolutionarily conserved genes associated with clinically important neural dysfunction. Because of the slower rate of gene evolution in this molluscan lineage, more homologs of genes associated with human disease are present in Aplysia than in leading model organisms from Arthropoda (Drosophila) or Nematoda (Caenorhabditis elegans). Research has hardly begun in molluscs on the cellular functions of gene products that in humans are associated with neurological diseases. On the other hand, much is known about molecular and cellular mechanisms of long-term neuronal plasticity. Persistent nociceptive sensitization of nociceptors in Aplysia displays many functional similarities to alterations in mammalian nociceptors associated with the clinical problem of chronic pain. Moreover, in Aplysia and mammals the same cell signaling pathways trigger persistent enhancement of excitability and synaptic transmission following noxious stimulation, and these highly conserved pathways are also used to induce memory traces in neural circuits of diverse species. This functional and molecular overlap in distantly related lineages and neuronal types supports the proposal that fundamental plasticity mechanisms important for memory, chronic pain, and other lasting alterations evolved from adaptive responses to peripheral injury in the earliest neurons. Molluscan preparations should become increasingly useful for comparative studies across phyla that can provide insight into cellular functions of clinically important genes.

Chronic volatile substance abuse among the adult Kickapoo traditional tribe of Texas: Disease and disability profiles, neuropsychosocial consequences, and social implications for treatment

The purpose of this study, based on secondary data from attendees at a substance abuse clinic for the Kickapoo Healing Grounds in Eagle Pass, Texas, is two fold: (1) to elucidate neuro-behavioral performance of volatile substance abusers in the Kickapoo tribe and (2) to determine factors associated with their treatment completion and rehabilitation as measured by their employment at follow-up. Volatile substance abuse (VSA) is associated with a host of neurological manifestations, and secondary prevention or clinical treatment and rehabilitation remains the mainstay of control efforts. Very little is known about VSA in general, and especially among Native American populations. It is anticipated that the results will help determine and assist other tribes and non-tribal substance abuse centers with treatment planning for volatile substance abusers among Native American populations. ^

DNA incisions stimulate genetic instability of triplet repeat sequences related to human hereditary neurological diseases

The molecular mechanisms responsible for the expansion and deletion of trinucleotide repeat sequences (TRS) are the focus of our studies. Several hereditary neurological diseases including Huntington's disease, myotonic dystrophy, and fragile X syndrome are associated with the instability of TRS. Using the well defined and controllable model system of Escherichia coli, the influences of three types of DNA incisions on genetic instability of CTG•CAG repeats were studied: DNA double-strand breaks (DSB), single-strand nicks, and single-strand gaps. The DNA incisions were generated in pUC19 derivatives by in vitro cleavage with restriction endonucleases. The cleaved DNA was then transformed into E. coli parental and mutant strains. Double-strand breaks induced deletions throughout the TRS region in an orientation dependent manner relative to the origin of replication. The extent of instability was enhanced by the repeat length and sequence (CTG•CAG vs. CGG•CCG). Mutations in recA and recBC increased deletions, mutations in recF stabilized the TRS, whereas mutations in ruvA had no effect. DSB were repaired by intramolecular recombination, versus an intermolecular gene conversion or crossover mechanism. 30 nt gaps formed a distinct 30 nt deletion product, whereas single strand nicks and gaps of 15 nts did not induce expansions or deletions. Formation of this deletion product required the CTG•CAG repeats to be present in the single-stranded region and was stimulated by E. coli DNA ligase, but was not dependent upon the RecFOR pathway. Models are presented to explain the DSB induced instabilities and formation of the 30 nucleotide deletion product. In addition to the in vitro creation of DSBs, several attempts to generate this incision in vivo with the use of EcoR I restriction modification systems were conducted. ^

Evaluation of the relationship between nutrition and functional independence measures among stroke patients undergoing inpatient rehabilitation

Cerebrovascular accidents (CVA) or strokes are now the third leading cause of death in the United States. Many who suffer strokes are admitted to rehabilitation centers in order to receive therapy to help rebuild and recovery function. Nutrition plays a significant role in rehabilitation patient outcomes, and is an essential part of comprehensive care. The purpose of this study is to determine if nutrition and diet consistency are directly and independently associated with changes in the Functional Independence Measure (FIM) scores in stroke patients in an acute rehabilitation unit. This study was a retrospective secondary analysis review of medical chart records, and included a total of 84 patients. Patients were divided into groups based on their admission diet: Regular, Dysphagia Advanced, Dysphagia Mechanically Altered, Dysphagia Pureed, and Nutrition Support. Measurements included admission and discharge Total, Motor, and Cognitive FIM scores; BMI, albumin and prealbumin; age, sex, and race. Patients did show a significant improvement in their FIM scores during their stay, with patients on Regular diets having the highest FIM scores. Patients who were more debilitated and had lower FIM scores were usually in one of the altered texture diet groups, or on nutrition support. Prealbumin and BMI were also the highest in patients who had high FIM scores. Patients who were admitted on an altered diet also tended to advance in their diets, which show improvement in overall function. It is crucial to continue to improve nutrition administration to this population to help prevent morbidity and mortality. Proper nutrition in the acute phase of stroke can lay the essential groundwork for recovery.^