1,720,972 research outputs found
Characterization of the Myo-inositol Efflux Pathway in Cultured Bovine Lens Epithelial Cells
Get PDFReeves, Rustin E., Characterization of the Myo-inositol Efflux Pathway in Cultured Bovine Lens Epithelial Cells. Doctor of Philosophy (Biomedical Sciences), December, 1997, 173 pp., 1 table, 28 figures, bibliography, 94 titles. The basic cellular requirement of volume regulation utilizes many different channel and transport pathways working on concord to maintain a constant cell volume. Among these are distinct pathways spontaneously activated by changes in cell volume that modulate the gain or loss of certain organic osmolytes, such as myo-inositol (MI). The major goal of this dissertation is to characterize and identify the mechanism involved in the MI effux pathway and explore its relationship with intracellular polyol accumulation in cultured bovine lens epithelial cells (BLECs). Hypertonic exposure of BLECs causes an increase in MI uptake and aldose reductase enzymatic activity, two events which ultimately influence osmolyte efflux. A biphasic efflux pathway induced by rapid cell swelling (hypotonic-induction) was demonstrated in BLECS switched from hypertonice to physiologic medium. Also, intracellular polyol accumulation from galactose exposure resulted in enhanced activation of the MI efflux pathway (polyol-induction). Chloride channel inhibitors effectively blocked MI efflux suggesting a relationship between anion (chloride) movement and intracellular MI loss from cell to medium. Expression of a chloride channel regulatory protein, pICln, was demonstrated by Northern blot analysis in cultured BLECs. Hypertonic exposure upregulates the expression of pICln mRNA while hypotonicity downregulates expression. The volume-sensitivity for transcription of PICln mRNA in BLECs lends strong support for its role in both anion and osmolyte loss associated with the MI efflux pathway. The MI efflux pathway functions as a “relief value” in cell volume regulation by providing a conduit to alleviate intracellular osmotic stress. The mechanism which evolved to function under normal cellular circumstances in relief of excessive accumulation of intracellular osmolytes (i.e. polyols), may, by design, inadvertently promote the loss of essential intracellular volume and nonvolume regulatory organic solutes. Ironically, under certain pathological conditions, this mechanism, designed to protect the cell from intracellular osmotic stress, may instead be detrimental to the cell by promoting the excessive loss of osmolytes essential for normal cell function
Bone Marrow Aspirate vs. Bone Morphogenetic Protein (rhBMP-2) in Multilevel Adult Spinal Deformity Surgery and the Feasibility of Using Adult Mesenchymal Stem Cells.
Get PDFPurpose: To evaluate bone graft substitutes used in spine fusion surgery and determine the feasibility of studying the use of adult stem cells.
Hypothesis: Using a well designed, randomized clinical trial to compare bone graft substitutes used in spine fusion surgery will help determine the best alternative to autologous bone graft.
Design: Retrospective data on two bone graft substitutes will be evaluated. A protocol for studying stem cells in spine fusion will be drafted and the feasibility of implementing the trial will be analyzed.
Results: It is difficult to design a randomized clinical trial to investigate a new surgical technique. The lack of standardization among spine surgeons makes it difficult to control for confounding variables
Quantifying Student Satisfaction and Academic Performance: A Comparison of Four Active Learning Techniques in an Asynchronous, Online, Graduate Anatomy Course
Get PDFA Novel Approach to Inquiry-Based Learning Models in the Sciences: Utilization of Case Presentations and Patient Encounter Workshops in High School Life Science Classrooms
Get PDFA Novel Approach to Inquiry-Based Learning Models in the Sciences: Utilization of Case Presentations and Patient Encounter Workshops in High School Life Science Classrooms. Lekeisha R. Whitaker. Abstract. A novel approach to inquiry-based learning models is needed in a curriculum that reflects changing demographics, societal demands, and diverse cultural background. The proposed module which is designed to teach the urinary system to Fort Worth Independent District high school biology students as outlined in the Texas Essential Knowledge and Skills (TEKS) guide, represents application of this novel tool in the classroom. It is designed to be implemented in inquiry-based learning classrooms that function to encourage the natural process of inquiry throughout grade levels. The proposed module takes advantage of media resources, introductory case reports, and patient encounter workshops that outline diet, disease, and health disparities as a way to capture student interest in content relevant material, engage students in the daily lessons, and invoke long-term retention of basic life science concepts. Through future research and testing of module design and effectiveness in the classroom, the proposed approach to inquiry-based learning may serve to optimize student understanding of fundamental science concepts and diet and disease as it relates to normal body function, with implications that may affect change in lifestyle. Furthermore, the proposed learning module, if effective, may also serve as a template to be used to teach other life science subjects
A Phase II Clinical Study to Evaluate the Efficacy and Safety of rhThrombin in Subjects Undergoing Arterial Bypass Surgery and AV Graft Formation for Hemodialysis
Get PDFThe Association of American Medical Colleges Task Force on Clinical Research defines clinical research as a component of medical and health research intended to produce knowledge essential for understanding human disease, preventing and treating illness, and promoting health (Friedman, 1998). A clinical trial is defined as a research study conducted in humans which is designed to answer specific questions using scientifically controlled conditions with specified methodologies and endpoints (Gallin, 2002). Clinical research trials are essential in determining whether or not a drug is safe and effective. There are four phases that investigational drugs go through before they are allowed to be out in the market. Before beginning phase I of a study, there is usually a pre-clinical research and development phase. During this time the initial synthesis of study drug is accomplished and animal testing takes place. Phase I is the initial introduction of an investigational new study drug into humans. Phase I is usually conducted in healthy individuals and the primary goal is to determine the safety profile of the drug. Phase II trials tend to evaluate safety and initial efficacy. Subjects enrolled in this phase tend to have the disease necessary for use of study drug. Phase III studies are conducted to gather additional information about the effectiveness and safety of the drug and to determine the overall benefit-risk relationship of the drug. Finally, phase IV studies are usually referred to as post-marketing studies. During this phase, additional safety information is identified and the drug’s safety during routine use is evaluated. Each phase can range from two to ten years depending on the complexity of the clinical trial (Gallin, 2002). A phase II, randomized, double blind study of the safety and efficacy of topical recombinant human thrombin in patients undergoing peripheral arterial bypass surgery and arterio-venous graft formation for hemodialysis is the focus of the prospective drug study to be carried out in the surgery department at The University of North Texas Health Science Center. The primary objective of this study is to evaluate the safety and efficacy of recombinant human thrombin when used in different types of surgeries. Prior to signing an informed consent, subjects will have to meet inclusion and exclusion criteria set by study protocol. Study specific assessments and procedures will be performed after the informed consent is signed and dated. If bleeding at the anastomosis is found to necessitate intervention, a single application of either rhThrombin or placebo in combination with an absorbable hemostatic sponge to each anastomosis requiring hemostasis will be applied by the surgeon. The safety and efficacy of rhThrombin will be determined by measuring the incidence and severity of adverse events and of laboratory abnormalities. Occurrence of hemostasis within 600 seconds of application of the study drug at the anastomotic surgical site, incidence of anti-rhThrombin product antibodies, and time to hemostasis will also be measured
Feasibility and Effectiveness of the GLB-AIM (Group Lifestyle Balance Adapted for Individuals With Impaired Mobility) Intervention for People Living with Spinal Cord Injury
Get PDFPurpose: The prevalence of obesity in the population living with spinal cord injury (SCI) is greater than the general population. Obesity linked coronary heart disease is a leading cause of morbidity and mortality in the population living with SCI. Behavioral interventions to promote weight loss are limited for the SCI population. GLB-AIM looks to address the lack of behavioral interventions by providing a feasible and effective program to promote weight loss for people living with SCI. Methods: The GLB-AIM was delivered to participants over the course of 12 months. The sample was assessed for feasibility as measured by attendance over 12-month program and compliance with dietary self-monitoring for the first 13 weeks. Effectiveness was evaluated by measuring weight change over 12 months. The data were analyzed using a mixed models analysis controlling for time living with injury, group assignment, and starting weight. Results: The 12-month retention rate was 62.5% (20/32), Session attendance for the core sessions averaged 74.6% and dropped to 48.9% during the support sessions. Dietary self-monitoring for group 1 averaged 33% over the first 13 sessions and increased to 77% among group 2. Analysis of the combined SCI groups indicated significant weight loss (p = 0.017) that averaged 5.03 +8.58 kg over the 12-month program. Discussion: The GLB-AIM was a feasible and effective approach for promoting weight loss over 12 months for a sample with SCI. Additional adaptations may increase attendance during the subsequent support sessions and reduce program attrition by addressing barriers related to health events and transportation issues. The GLB-AIM program promoted weight loss in people living with SCI, which highlights the program’s effectiveness. Future adaptations of the GLBAIM should seek to enhance weight loss through increased weight feedback and the providing individualized calorie targets
The Effect of Dietary Loading on Structural Determinants of Force Production in the Rat Masseter
Get PDFRossiter, Jeffrey A., The Effect of Dietary Loading on Structural Determinants of Force Production in the Rat Masseter. Master of Science in Medical Sciences - Anatomy, May 2020. Biomechanical loading associated with feeding is known to direct cranial bone growth, however less is known about its effects on masticatory muscle growth and performance. Peak muscle contractile forces are determined by a combination of factors including total muscle mass, fiber length, and fiber type. Here, we test two hypotheses: that mechanically challenging diets will (1) increase the physiological cross-sectional area (PCSA), an estimate of maximum contractile force at tetanus, and (2) increase the number and proportion of type II (fast-twitch) muscle fibers in the masseter of the rat. Sprague-Dawley rats were raised on either a hard/tough (overuse) diet or a soft (underuse) diet (n=5/cohort). The superficial masseters were dissected and photographed using a trifocal stereo microscope, and muscle fiber length (6/individual) were measured using ImageJ. Muscle volumes were calculated from in-situ diffusible iodine-based contrast-enhanced μCT scans. Muscles were stained using an IHC protocol for the fast isoform of myosin heavy chain, allowing the number and areas of type II (stained) and type I (unstained) fibers to be quantified in ImageJ. Results from this study do not support our hypotheses, most likely due to the small sample sizes (n=5/treatment group) available for this study. Paradoxical results were found, with rats raised on a soft diet tending to have longer superficial masseter muscle fibers and more type II muscle fibers with larger cross-sectional areas in the posterior masseter. Rats raised on a hard diet tend to have larger masseter muscle volumes. However, these trends were not statistically significant (p > 0.05). Mechanically challenging diets tend to be associated with greater masticatory muscle volumes and thus increased PCSA. The fiber type results from the posterior masseter (with more deep masseter fibers) were the opposite of those previous results from the middle masseter (with more superficial masseter fibers) in the same animals. Future studies with increased sample sizes are needed to better understand the structural determinants of force production in the rat masseter
Localizing the Sciatic Nerve in the Gluteal Region Using Surface Projections: A Cadaveric Study
No full textLocalization of the sciatic nerve (SN) for pain management commonly relies on ultrasound (US), but that resource may not be available in some rural health clinics and impoverished countries. The purpose of this study is to investigate the use of surface projections within the gluteal region (GR), which are the greater trochanter (GT), ischial tuberosity (IT), and the apex of the sacral hiatus (ASH), to localize the SN and assess sex differences of the SN in orientation to those landmarks. We hypothesize that if the GT, IT, and ASH are reliable in localizing the SN, then we will be able to localize the SN with a reliability greater than or equal to 80%. Using 14 embalmed, OMS-I dissected cadaveric specimens (seven males, seven females), nine different measurements were taken using a digital caliper to establish the orientation of the SN to the GT, IT, and ASH within the GR. Using this data, two reference points (one superior: one inferior) for the SN were identified on the left and right GR of 10 fresh frozen cadavers (five males, five females). Pink latex was injected at the superior point; blue latex at the inferior point, followed by a simple gluteus maximus muscle dissection to verify the location of the latex to the SN. A Welch's t-test was used to analyze any sex differences between the left and right GR, and a Student t-test was used to compare the left and right GR within each sex. There was no significant difference between the nine measurements found within each sex; however, between each sex, there were several measurements that displayed significant differences. Latex injected into the superior point proved better for localizing the SN without using US. Although there were significant differences in the SN measurements between the sexes, the study showed that these three bony landmarks could locate the sciatic nerve accurately. This method could provide clinicians who lack the resources of US or other imaging modalities to localize the SN reliably
A Cadaveric Investigation of the Dorsal Scapular Nerve
Get PDFDorsal scapular nerve (DSN) syndrome is often associated with sharp, dull, or aching pain in the upper extremity and back. The primary cause of pain is the entrapment of this nerve at the middle scalene muscle. Even though there is clinical evidence that DSN syndrome exists, it is often overlooked during clinical diagnosis. The purpose of this study is to locate the surface projection of the DSN relative to the middle scalene muscle while using the laryngeal prominence as a reference point. From 20 embalmed adult cadavers, 23 DSN were dissected and documented regarding its spinal root origins, anatomical route, and muscular innervations. A transverse plane through the laryngeal prominence was established to measure the distance of the DSN as it enters, crosses, and exits the middle scalene muscle. Approximately 70% of the DSNs originated from C5, 22% branched from C4, and 8% from C6. In regards to the route of the DSN in relation to the middle scalene muscle, 74% of the DSNs pierced this muscle, 13% crossed this muscle anteriorly, and 13% traveled posterior to this muscle. About 48% of the DSNs supplied the levator scapulae muscle only and 52% innervated the levator scapulae and both the rhomboid muscles. The average distances from a transverse plane of the laryngeal prominence to where the DSN entered, crossed, and exited the middle scalene muscle were 1.50 cm (±0.88 cm), 1.79cm (±0.89 cm), and 2.08 cm (±0.96 cm) respectively. Injection studies were performed on 10 un-dissected embalmed cadavers to verify the accuracy of our surface projection measurements of the DSN relative to the middle scalene muscle. These injections were performed at approximately 2.08 cm (~1 thumb interphalangeal joint width) from the transverse plane of the laryngeal prominence. Dissections at these injection sites revealed that the scalene muscles were consistently located. The middle scalene muscle was accurately located in approximately 50% of the injections. The goal of this research is to understand the variability in DSN's anatomy as well as introduce a method that will assist clinicians to efficiently pinpoint and therefore treat patients with DSN entrapment
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