Physiology Commons^™

Physiologically-Based Pharmacokinetic Modeling For Predicting Caffeine/Theophylline-Ciprofloxacin Interactions, David M. Ng, Ali Navid

STAR Program Research Presentations

Dynamics of interactions between the drugs caffeine, theophylline, and ciprofloxacin are predicted using physiologically-based pharmacokinetic (PBPK) modeling. Pharmacokinetic means the model determines where the drugs are distributed in the body over time. Physiologically-based means the anatomy and physiology of the human body are reflected in the structure and functioning of the model. Multiple drugs can interact to increase or decrease their beneficial and/or undesired effects. This is important because some common substances, such as caffeine in coffee, soft drinks, and energy drinks, are actually drugs that affect the body. Ciprofloxacin is an inhibitor of caffeine and theophylline metabolism; such inhibition …

The Relationship Among Ankle Function, Functional Capacity, And Body Composition To Balance In Geriatric Populations, Joseph Robert Chaney

Graduate Theses and Dissertations

The primary purpose of this research study was to identify significant relationships among measures of ankle strength, ankle range of motion, body composition, and functional capacity to balance ability in geriatric populations which may potentially assist in identifying older individuals with increased risk of falling. A battery of five test (ankle strength assessments, ankle range of motion , DXA, functional fitness, and balance) were administered to 20 participants (6 males, 14 females, mean age 69.78 ± 3.98) that had indicated to be at least 65 years of age or older and no history of falls within the previous 12 months. …

Med13p Prevents Stress-Independent Mitochondrial Hyperfragmentation And Aberrant Apoptosis Activation In Saccharomyces Cerevisiae By Controlling Cyclin C Nuclear Localization, Svetlana Khakhina

Graduate School of Biomedical Sciences Theses and Dissertations

During aging, and as a result of environmental changes, cells are exposed to elevated levels of reactive oxygen species (ROS). High ROS levels induce lipid oxidation, protein aggregation, mitochondrial hyperfragmentation, DNA damage and programmed cell death (PCD), also called apoptosis. PCD is a highly regulated process and its misregulation has been linked to neurodegenerative diseases and cancer development.

Our hypothesis is that cyclin C plays a role in the initiation of apoptosis. During normal conditions, cyclin C represses the transcription of stress response genes (SRG). In response to stress, cyclin C translocates to the cytoplasm where it facilitates mitochondrial hyperfragmentation …

Surfing Injuries Requiring First Aid In New Zealand, 2007-2012, Kevin Moran, Jonathon Webber

International Journal of Aquatic Research and Education

In an island nation such as New Zealand with easy access to surf beaches, surfing activities are very popular and, while generally perceived as a healthy form of outdoor recreation, they do have attendant risks. This study reports on nondrowning, surfing-related incidents that required medical first aid on beaches during five summer seasons from 2007-2012. Retrospective descriptive analysis of data from lifeguard first aid reports found that 16% (n = 1,327) of injuries were the consequence of surfing activity. More males than females were treated for surfing injuries (68% male, 31% female). Lacerations (59%) and bruising (15%) accounted for most …

The Effect Of Temperature Extremes On Cardiorespiratory Function In The Grass Shrimp Palaemonetes Pugio: Oxygen Limited Thermal Tolerance, Teresa Mika

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aquatic poikilothermic animals must either cope with or compensate for the mismatch in oxygen supply and demand present at high temperatures. Oxygen limited thermal tolerance explains how aerobic scope is limited by insufficient oxygen supply and sets the performance window in animals. This work explores the effects of temperature on the different components of the oxygen delivery system, in both normoxic and hyperoxic conditions to determine if supplying more oxygen to the system mitigates the effects of temperature effects on the cardiorespiratory system and extends oxygen limited thermal tolerance to higher temperatures. The effect of temperature and oxygen condition was …

Skin Diseases And Non-Syndromic Hearing Loss Linked To Cx30 Mutations Arise Through Several Distinct Mechanisms, Amy C. Berger

Electronic Thesis and Dissertation Repository

Connexin 30 (Cx30), a member of the large gap junction protein family, plays a role in the homeostasis of the epidermis and inner ear through gap junctional intercellular communication (GJIC). Here, we investigated four autosomal dominant Cx30 gene mutations linked to hearing loss and/or various skin diseases. First, the T5M mutant linked to non-syndromic hearing loss formed functional gap junction channels and hemichannels, similar to wild-type Cx30. The V37E mutant associated with keratitis-ichthyosis-deafness (KID) syndrome was retained in the endoplasmic reticulum (ER) and significantly induced unfolded protein response (UPR)-mediated apoptosis. The loss-of-function G59R mutant linked to Vohwinkel and Bart-Pumphrey syndromes …

Spinal Cord Control Of Ejaculatory Reflexes In Male Rats, Natalie Kozyrev

Electronic Thesis and Dissertation Repository

Ejaculatory dysfunction impacts large numbers of men of all ages and around the world. In addition, a great majority of men with chronic spinal cord injury (SCI) experience ejaculatory dysfunction, which negatively impacts the quality of life of these individuals and their partners. SCI men emphasize the significance of regaining sexual function as their main goal. Currently, there is a marked absence of literature reporting the alterations to sexual function and ejaculation in particular in animal models of chronic SCI. In addition, there are many unanswered questions pertaining to the spinal cord control of ejaculation in healthy, intact men. It …

Dexamethasone Rapidly Increases Gaba Release In The Dorsal Motor Nucleus Of The Vagus Via Retrograde Messenger-Mediated Enhancement Of Trpv1 Activity, Andrei V. Derbenev, Bret N. Smith

Physiology Faculty Publications

Glucocorticoids influence vagal parasympathetic output to the viscera via mechanisms that include modulation of neural circuitry in the dorsal vagal complex, a principal autonomic regulatory center. Glucocorticoids can modulate synaptic neurotransmitter release elsewhere in the brain by inducing release of retrograde signalling molecules. We tested the hypothesis that the glucocorticoid agonist dexamethasone (DEX) modulates GABA release in the rat dorsal motor nucleus of the vagus (DMV). Whole-cell patch-clamp recordings revealed that DEX (1-10 µM) rapidly (i.e. within three minutes) increased the frequency of tetrodotoxin-resistant, miniature IPSCs (mIPSCs) in 67% of DMV neurons recorded in acutely prepared slices. Glutamate-mediated mEPSCs were …

Traumatic Injury In Vitro Elicits Jnk-Mediated Human Astrocyte Retraction, But Spares Cerebrovascular Endothelial Cells, Claudia Augustine

Electronic Thesis and Dissertation Repository

The pathophysiology of a traumatic brain injury (TBI) involves the dysfunction of the blood-brain barrier (BBB). The lumen of the BBB is lined with cerebrovascular endothelial cells (CVEC) that are ensheathed with perivascular astrocyte endfeet. We investigated the cellular response of human-astrocytes and human-CVEC following trauma in vitro. Astrocytes and CVEC were subjected to a concussive injury (CI; mechanical stretch), then assessed for markers of injury (monolayer retraction) and activation (mitogen-activated protein kinases (MAPK) phosphorylation).

CI induces astrocyte monolayer retraction and activation, with predominant phosphorylation of JNK1/2 MAPK. Interfering with JNK1/2 activation (selective JNK inhibitors) reduces trauma-induced astrocyte retraction. On …

Direction Of Aminoacylated Transfer Rnas Into Antibiotic Synthesis And Peptidoglycan-Mediated Antibiotic Resistance, Jennifer Shepherd, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Prokaryotic aminoacylated‐transfer RNAs often need to be efficiently segregated between translation and other cellular biosynthetic pathways. Many clinically relevant bacteria, including Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa direct some aminoacylated‐tRNA species into peptidoglycan biosynthesis and/or membrane phospholipid modification. Subsequent indirect peptidoglycan cross‐linkage or change in membrane permeability is often a prerequisite for high‐level antibiotic resistance. In Streptomycetes, aminoacylated‐tRNA species are used for antibiotic synthesis as well as antibiotic resistance. The direction of coding aminoacylated‐tRNA molecules away from translation and into antibiotic resistance and synthesis pathways are discussed in this review.

Paired Interactions Between Kir Channels And Tertiapin-Q, Chul Ho Yang

Theses and Dissertations

Kir channels serve diverse and important roles throughout the human body and malfunctions of these channels are implicated in various channelopathies. Specific inhibitors for different subtypes of Kir channels are not available. However, Tertiapin-Q (TPNQ), a polypeptide isolated from honey bee venom, differentially inhibits certain subtypes of Kir channels with nanomolar affinity: ROMK1 (Kir1.1) and GIRK1/GIRK4 (Kir3.1/Kir3.4). Modification of TPNQ to increase selectivity for target channels bears great therapeutic potential. The in silico studies based on TPNQ-docked channel models, ROMK1_IRK2 (Kir1.1_Kir2.2) and GIRK2 (Kir3.2), predicted specific paired residue interactions and were experimentally validated here. In ROMK1 E123A mutant, the TPNQ …

Preseason And Post Season Body Composition Does Not Change Relative To Playing Time In Division I Female Basketball Players, Emma Ladwig, Andrew Shim, Jae Yom, Patrick Cross, Justin Beebe

Andrew L Shim

International Journal of Exercise Science 6(3) : 208-216, 2013. The purpose of the study was to determine if preseason and postseason body fat percentages (BF%) change relative to playing time in Division I women’s basketball players. Subjects for the study included 11 National Collegiate Athletic Association (NCAA) Division I female collegiate basketball athletes over the age of 18 from a Midwest public university. Demographic data of each subject (age 20.09 +1.81 yrs., weight 71.13 +10.85 kg., height 176.48 + 8.33 cm.) was taken before the initial body fat assessment. The subjects underwent preseason and postseason BOD POD® testing to get …

Lipid Ii-Independent Trans Editing Of Mischarged Trnas By The Penicillin Resistance Factor Murm, Jennifer Shepherd, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Streptococcus pneumoniae is a causative agent of nosocomial infections such as pneumonia, meningitis, and septicemia. Penicillin resistance in S. pneumoniae depends in part upon MurM, an aminoacyl-tRNA ligase that attaches l-serine or l-alanine to the stem peptide lysine of Lipid II in cell wall peptidoglycan. To investigate the exact substrates the translation machinery provides MurM, quality control by alanyl-tRNA synthetase (AlaRS) was investigated. AlaRS mischarged serine and glycine to tRNAAla, as observed in other bacteria, and also transferred alanine, serine, and glycine to tRNA^Phe. S. pneumoniae tRNA^Phe has an unusual U4:C69 mismatch in its acceptor stem that …

Aging And Obesity Models In Osteoarthritis, Sara Ohora

Electronic Thesis and Dissertation Repository

Osteoarthritis (OA) is a degenerative joint disease whose exact mechanisms are not well understood, but aging and obesity are common risk factors. To determine the role of transforming growth factor-alpha (TGFα) in obesity-associated OA, Tgfa null and control mice on control and high fat diets were compared. In addition, spontaneous OA was investigated in aging C57BL/6J mice. Quantitative magnetic resonance was used to assess body composition in the obesity model, while gait analysis, histological staining and OARSI scoring were used to determine OA in both models. Mice on high fat diet developed no OA, but Tgfa null mice weighed significantly …

Acquisition Delays Affect Lymphocyte Subset Counts But Not Markers Of Exercise-Induced Apoptosis, Holly B. Kell, Guilherme Borges Pereira, Ramires Alsamir Tibana, Michael Jarrett, Mark A. Schafer, Jonato Prestes, Antonio Santo, James W. Navalta

International Journal of Exercise Science

International Journal of Exercise Science 6(3) : 250-255, 2013. With the emergence of shared facilities, the possibility of a processing delay is increased as time on instrumentation becomes less available. The purpose of this investigation was the evaluate the effect of a 24h time delay on lymphocyte subset concentration, as well as for the apoptotic marker annexin V. Fourteen healthy individuals completed an incremental treadmill test to exhaustion, and blood samples were obtained before and after exercise. The samples were labeled in duplicate with mixtures consisting of flow cytometry staining buffer, the biomarker for early-phase cell death (annexin V), and …

Activity-Specific Effects Of Fatigue Protocols May Influence Landing Kinematics: A Pilot Study, Adrian Chavez, Duane Knudson, Rod Harter, Kevin Mccurdy

International Journal of Exercise Science

International Journal of Exercise Science 6(3) : 242-249, 2013. Fatigue is a common neuromuscular factor examined in relation to risk of ACL injury. Unfortunately, variations between the protocols used to induce fatigue in studies examining this phenomenon may have contributed to reported inconsistencies in the effects of fatigue on movements with high-risk of ACL injury. In addition, the ecological validity of fatigue experienced as a result of protocols commonly administered in the experimental setting is unclear. The purpose of this study was to examine the ecological validity, using basketball competition as the criterion measure, of two fatigue protocols commonly used …

Manuscript Has Been Retracted, Michael Smith, Nicholas Hanson, Alexander Lucas, Steven Devor

International Journal of Exercise Science

International Journal of Exercise Science 6(3) : 236-241, 2013. Manuscript has been retracted.

Children And Pedometers: A Study In Reactivity And Knowledge, Steven L. Prewitt, James C. Hannon, Timothy A. Brusseau

International Journal of Exercise Science

International Journal of Exercise Science 6(3) : 230-235, 2013. Pedometers are simple inexpensive tools that are widely used for the measurement of physical activity. Reactivity is always a concern when using pedometers. An issue not yet addressed is the role previous knowledge has on the impact of reactivity. The primary purpose of this study was to examine if reactivity exists in 4^th-6^th grade students and if prior knowledge about pedometers had an effect on reactivity. Participants included 109 (54 females) 4^th- 6^th grade students from a suburban charter school. Prior to data collection, students …

Measuring Activity Energy Expenditure: Accuracy Of The Gt3x+ And Actiheart Monitors, David Mcminn, Rijan Acharya, David A. Rowe, Stuart R. Gray, Julia L. Allan

International Journal of Exercise Science

International Journal of Exercise Science 6(3) : 217-229, 2013. The purpose was to determine the accuracy of the GT3X+ and Actiheart monitors for estimating energy expenditure (EE) and steps. Additionally, to investigate agreement between waist- and wrist-mounted GT3X+ EE outputs. Nineteen participants (mean age=30) completed three treadmill walking trials at self-selected slow, medium, and fast speeds while wearing two GT3X+ (waist and wrist) and an Actiheart. Activity monitor EE was compared to indirect calorimetry criterion EE using Pearson correlations and ANOVAs. A Bland-Altman plot was used to investigate agreement between GT3X+ waist- and wrist-determined EE. GT3X+ determined steps were compared …

Preseason And Post Season Body Composition Does Not Change Relative To Playing Time In Division I Female Basketball Players, Emma Ladwig, Andrew L. Shim, Jae P. Yom, Patrick Cross, Justin Beebe

International Journal of Exercise Science

International Journal of Exercise Science 6(3) : 208-216, 2013. The purpose of the study was to determine if preseason and postseason body fat percentages (BF%) change relative to playing time in Division I women’s basketball players. Subjects for the study included 11 National Collegiate Athletic Association (NCAA) Division I female collegiate basketball athletes over the age of 18 from a Midwest public university. Demographic data of each subject (age 20.09 +1.81 yrs., weight 71.13 +10.85 kg., height 176.48 + 8.33 cm.) was taken before the initial body fat assessment. The subjects underwent preseason and postseason BOD POD^® testing to …