Physiology Commons^™

Effect Of Muscle Length On Cross-Bridge Kinetics In Intact Cardiac Trabeculae At Body Temperature, Nima Milani-Nejad, Ying Xu, Jonathan P. Davis, Kenneth S. Campbell, Paul M. L. Janssen

Physiology Faculty Publications

Dynamic force generation in cardiac muscle, which determines cardiac pumping activity, depends on both the number of sarcomeric cross-bridges and on their cycling kinetics. The Frank–Starling mechanism dictates that cardiac force development increases with increasing cardiac muscle length (corresponding to increased ventricular volume). It is, however, unclear to what extent this increase in cardiac muscle length affects the rate of cross-bridge cycling. Previous studies using permeabilized cardiac preparations, sub-physiological temperatures, or both have obtained conflicting results. Here, we developed a protocol that allowed us to reliably and reproducibly measure the rate of tension redevelopment (k_tr; which depends …

Orofacial Neuropathic Pain Mouse Model Induced By Trigeminal Inflammatory Compression (Tic) Of The Infraorbital Nerve, Fei Ma, Liping Zhang, Danielle Lyons, Karin N. Westlund

Physiology Faculty Publications

BACKGROUND: Trigeminal neuropathic pain attacks can be excruciating for patients, even after being lightly touched. Although there are rodent trigeminal nerve research models to study orofacial pain, few models have been applied to studies in mice. A mouse trigeminal inflammatory compression (TIC) model is introduced here which successfully and reliably promotes vibrissal whisker pad hypersensitivity.

RESULTS: The chronic orofacial neuropathic pain model is induced after surgical placement of chromic gut suture in the infraorbital nerve fissure in the maxillary bone. Slight compression and chemical effects of the chromic gut suture on the portion of the infraorbital nerve contacted cause mild …

The Effects Of Intracerebroventricular Leptin On Milk Availability In Lactating Rats, Brittany Lynita Moore

Electronic Theses and Dissertations

Reports have linked energy balance along with adipocyte derived leptin action to improved fertility. Recent evidence indicates that leptin hormone is present in breast milk and leptin receptors are well expressed in mammary epithelial cells. The hypothesis that insufficiency of leptin restraint in the hypothalamus may underlie infertility in rodents and the failure of lactating breast to express adequate amount of milk was tested. Female Sprague-Dawley rats were injected leptin through intracerebroventricular cannulation (ICVC) of the third ventricle. Female rats were mated with stud males and observed throughout gestation. Compared to the control groups, leptin treatment increased prolactin levels in …

Long-Term Depression Of Excitatory Inputs To Gabaergic Neurons In The Ventral Tegmental Area, Philip J. Sandoval

Theses and Dissertations

Dopamine cells within the ventral tegmental area of the brain are involved in motivation and reward. Drugs of abuse target these dopamine cells altering their activity and plasticity resulting in addiction. While dopamine cell activity is primarily involved in addiction, the GABA neurons in the VTA have also been shown to have an indirect role. By decreasing the activity of the inhibitory GABA inputs onto dopamine neurons abusive drugs can indirectly increase dopamine cell activity resulting in addictive behaviors. However, although GABA neurons are important in the perception of reward, much less is known about how the excitatory inputs to …

Theta Dynamics: Speed, Acceleration And Contribution To Cognition, Lauren L. Long

Master's Theses

No abstract provided.

Selection Of Trna Charging Quality Control Mechanisms That Increase Mistranslation Of The Genetic Code, Srujana S. Yadavalli, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Mistranslation can follow two events during protein synthesis: production of non-cognate amino acid:transfer RNA (tRNA) pairs by aminoacyl-tRNA synthetases (aaRSs) and inaccurate selection of aminoacyl-tRNAs by the ribosome. Many aaRSs actively edit non-cognate amino acids, but editing mechanisms are not evolutionarily conserved, and their physiological significance remains unclear. To address the connection between aaRSs and mistranslation, the evolutionary divergence of tyrosine editing by phenylalanyl-tRNA synthetase (PheRS) was used as a model. Certain PheRSs are naturally error prone, most notably a Mycoplasma example that displayed a low level of specificity consistent with elevated mistranslation of the proteome. Mycoplasma PheRS was found …

Acute Exercise And Its Effect On Cognitive Performance In Sleep Deprived Individuals: A Review Of Literature., Jennifer Nicole Miller

Undergraduate Honors Theses

This literature review observes seven different studies that researched the effects of exercise on some measure of cognitive or psychological performance when sleep deprived. The purpose of this review is to consolidate the results of various exercise protocols on the effects of sleep deprivation to make a general conclusion regarding the effect on cognition. This will give insight into the future of research regarding how exercise may combat performance decrements seen when sleep deprived. There are several inconsistencies among current research concerning exercise and sleep deprivation; a standard needs to be created so the results of these studies can be …

House Finches, Carpodacus Mexicanus: Hormones, Stress, And Song Control Regions, Katherine Olivia Ganster

Master's Theses

Song production in songbirds is controlled by parts of the brain known as the song control regions (SCRs). During spring, gonads increase in size, males sing to attract mates, and SCRs become larger. This neuroplasticity is controlled by the change in day length and increased plasma testosterone (T) levels. Plasma T can be reduced by stress through the production of corticosterone (CORT), through the production of beta-endorphin, or through direct effects on the testes via the nervous system. We determined the T, estradiol, and CORT hormonal profiles of wild House Finches by capturing and sampling blood from the finches every …

Late Embryogenesis Abundant Proteins Protect Human Hepatoma Cells During Acute Desiccation, Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael A. Menze, Mehmet Toner, Steven C. Hand

Faculty Research & Creative Activity

Expression of late embryogenesis abundant (LEA) proteins is highly correlated with desiccation tolerance in anhydrobiotic animals, selected land plants, and bacteria. Genes encoding two LEA proteins, one localized to the cytoplasm/nucleus (AfrLEA2) and one targeted to mitochondria (AfrLEA3m), were stably transfected into human HepG2 cells. A trehalose transporterwas used for intracellular loading of this disaccharide. Cellswere rapidly and uniformly desiccated to low water content (<0.12 g H2O/g dry weight) with a recently developed spin-drying technique. Immediately on rehydration, control cells without LEA proteins or trehalose exhibited 0% membrane integrity, comparedwith 98% in cells loaded with trehalose and expressing AfrLEA2 or AfrLEA3m; surprisingly, AfrLEA3m without trehalose conferred 94% protection. Cell proliferation across 7 d showed an 18-fold increase for cells dried with AfrLEA3m and trehalose, compared with 27-fold for nondried controls. LEA proteins dramatically enhance desiccation tolerance in mammalian cells and offer the opportunity for engineering biostability in the dried state.

Late Embryogenesis Abundant Proteins Protect Human Hepatoma Cells During Acute Desiccation., Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael Menze, Mehmet Toner, Steven Hand

Faculty and Staff Scholarship

Expression of late embryogenesis abundant (LEA) proteins is highly correlated with desiccation tolerance in anhydrobiotic animals, selected land plants, and bacteria. Genes encoding two LEA proteins, one localized to the cytoplasm/nucleus (AfrLEA2) and one targeted to mitochondria (AfrLEA3m), were stably transfected into human HepG2 cells. A trehalose transporterwas used for intracellular loading of this disaccharide. Cellswere rapidly and uniformly desiccated to low water content (< 0.12 g H2O/g dry weight) with a recently developed spin-drying technique. Immediately on rehydration, control cells without LEA proteins or trehalose exhibited 0% membrane integrity, comparedwith 98% in cells loaded with trehalose and expressing AfrLEA2 or AfrLEA3m; surprisingly, AfrLEA3m without trehalose conferred 94% protection. Cell proliferation across 7 d showed an 18-fold increase for cells dried with AfrLEA3m and trehalose, compared with 27-fold for nondried controls. LEA proteins dramatically enhance desiccation tolerance in mammalian cells and offer the opportunity for engineering biostability in the dried state.

A Novel Method For Comparative Analysis Of Retinal Specialization Traits From Topographic Maps, Bret A. Moore, Jason M. Kamilar, Shaun P. Collin, Olaf R. P. Bininda-Emonds, Nathaniel J. Dominy, Margaret I. Hall, Christopher P. Hessy, Sonke Johnsen, Thomas J. Lisney, Ellis R. Loew, Gillian Moritz

Dartmouth Scholarship

Abstract Vertebrates possess different types of retinal specializations that vary in number, size, shape, and position in the retina. This diversity in retinal configuration has been revealed through topographic maps, which show variations in neuron density across the retina. Although topographic maps of about 300 vertebrates are available, there is no method for characterizing retinal traits quantitatively. Our goal is to present a novel method to standardize information on the position of the retinal specializations and changes in retinal ganglion cell (RGC) density across the retina from published topographic maps. We measured the position of the retinal specialization using two …

Novel Strategies To Improve Metabolic Parameters And Precondition Diabetic Hearts Against Ischemia/Reperfusion Injury, Amit Varma

Theses and Dissertations

Insulin resistance and chronic hyperglycemia promote vascular damage, increase circulating levels of inflammatory cytokines and lead to increased morbidity and mortality. MicroRNAs (miRs) -103/107 have been shown to negatively regulate insulin sensitivity and glucose homeostasis. Based on complimentary binding profiles, the downstream target gene of miR-103/107 is caveolin-1 (Cav-1). We hypothesized that daily administration of the phosphodiesterase-5 inhibitor tadalafil (TAD) ± the curcumin analogue (HO-3867) will attenuate inflammation, improve metabolic parameters and reduce infarct size after ischemia/reperfusion injury (IRI). Furthermore, we propose that TAD therapy will reduce myocardial expression of miR-103/107 and increase mRNA and protein levels of its target …

Regulation Of Sensory Neurogenesis In The Trigeminal Placode: Notch Pathway Genes, Pax3 Isoforms, And Wnt Ligands, Jason Samuel Adams

Theses and Dissertations

This dissertation is divided into three chapters, each discussing the study of different regulatory molecules involved in sensory neurogenesis occurring in the trigeminal placode. Chapter one is a spatiotemporal description of Notch pathway genes in chick opV placode by stage-specific expression analysis, showing expression of many Notch pathway genes and effectors in the opV placode. Notch pathway gene expression is primarily confined to the ectoderm with highest expression of these genes at the beginning stages of peak neuronal differentiation. This information preceded studies of the functional roles that Notch signaling has in the opV placode and how it may affect …

Physical Activity Among Mexicans And Mexican Americans In An Ecologic Systems Framework, Rebecca E. Lee, Lorna Mcneill, Lucie Levesque, Cynthia M. Castro, Edtna Jauregui

International Journal of Exercise Science: Conference Proceedings

Purpose: To operationalize the Ecologic Model of Physical Activity (EMPA) in an environmental and cultural context born in Mexico, but broadly adopted by Mexican Americans in the USA. Methods: Participant observation occurred over an immersive, ten month period in Jalisco, Baja California South, and the Distrito Federal, Mexico. Numerous meetings with researchers, school personnel, state health departments, and residents helped define environmental factors, cultural values, and the political context of Mexico. The EMPA was adapted to include examples from physical activity resources, health care settings and behavioral interventions. Results: Mexico is a middle income country leapfrogging from traditional physical activities …

Gender Difference In Obesity And Preventive Health Behaviors In A Us-Mexico Border Hispanic Cohort, Jing Wang, Belinda M. Reininger, Stanley Cron, Deidra Carroll, Susan P. Fisher-Hoch

International Journal of Exercise Science: Conference Proceedings

Purpose: Overweight and obesity is a prevalent chronic disorder in Mexican Americans, however, obesity-related behaviors and the role of gender remain unclear. This study examined gender difference in obesity-related health behaviors among Mexican Americans. Methods: A sample (n=1439) was drawn from the Cameron County Hispanic Cohort, a prospective cohort sample of Mexican American adults aged 18 years and older living in a large and poor city along the Texas / Mexico border. The participants’ baseline demographic, behavioral, and clinical measures were used for this analysis. Descriptive statistics and chi-square tests were conducted to analyze the data. Results: The sample had …

Healthy Bites: A Challenge-Based Worksite Wellness Nutrition Program, Mary E. Herndon, Adelina J. Espat, Laura R. Nathan-Garner

International Journal of Exercise Science: Conference Proceedings

Purpose: The worksite health promotion literature has shown that successful nutrition communication programs call for making small changes to diet, one at a time. The use of observational learning (role models) and a “challenge” scenario for behavior change is supported by Social Cognitive Theory. The significance of these small changes in worksites is underscored by a recent Harvard Business Review article suggesting workplace wellness programs can return up $2.71 on every $1.00 invested. The purpose of the proposed program, Healthy Bites, is to increase knowledge of employees regarding the impact of specific nutrition behaviors related to reducing cancer risk and …

Physical Activity Among Asian American Adults: Data From The 2010 Health Of Houston Survey, Dennis Kao, Amy Carvalho, Rebecca E. Lee

International Journal of Exercise Science: Conference Proceedings

Purpose: The Asian American population represents the fastest growing minority groups in the US; yet, little is still known about physical activity (PA) among Asian Americans. This study examines PA among Asian American adults living in the Houston, TX area. Methods: Data on adults aged 18 and over were drawn from the Health of Houston Survey 2010—a population-based survey focused in the city of Houston and Harris County. PA was operationalized in two ways: number of moderate leisure-time PA days in the past week; and meeting CDC recommendations for aerobic exercise. Multivariate regression models (negative binomial and logistic) were used …

Using Housing Market Information To Improve Evaluation Of Physical Activity., Michael C. Farmer, Michael S. Shiroya

International Journal of Exercise Science: Conference Proceedings

Purpose: Heterogeneity exists in urban neighborhoods. Factors that affect home choice can differ even though socio-demographics are quite similar. It is possible residents’ tastes for environment features in home location also predict how well they respond to built-environment changes by increasing physical activity. Observing factors that affect location can contribute to physical activity success in public health. A study area in West Texas appears very homogeneous: 89% Caucasian; 72% registered Republican; 81% families with children; 68% college educated - 87% ‘some college;’ yet two distinct submarkets exist based on subtle differences in home purchase choices. The area has a high …

The Impact Of Home Availability Of The Relationship Between Neighborhood Availability And Fruit And Vegetable Conumption In Low-Income Ethnic Minorities, Erica Soltero, Scherezade K. Mama, Rebecca E. Lee

International Journal of Exercise Science: Conference Proceedings

Purpose: High availability of grocery stores and supermarkets has been positively associated with increased fruit and vegetable consumption, yet some studies have reported that the relationship between availability and consumption is equivocal or inconclusive indicating that availability does not directly translate to increased consumption. The purpose of this study was to investigate the mediating effect of home availability of fruits and vegetables on the relationship between neighborhood availability of supermarkets and grocery stores and fruit and vegetable consumption in low-income, ethnic minority neighborhoods. Methods: Data used in this study was taken from the Healthful Options Using Streets and Transportation in …

The Physical Activity Promotion Environment In Mexican Health Care Settings, Karla I. Galaviz, Lucie Lévesque, Rebecca Lee, Kim Bergeron

International Journal of Exercise Science: Conference Proceedings

Purpose: The health care environment is recognized as a promising setting in which to promote physical activity (PA). Nearly 40% of Mexican adults are inactive and whether Mexican health care environments are promoting PA is unknown. The purpose of this study was to describe and compare the PA promotion environment in Guadalajara, Mexico. Methods: Forty primary care clinics and hospitals from the three health care systems in Guadalajara were sampled: 15 from the Secretary of Health, 14 from the Social Security Institutes and 11 from the private sector. A tool for measuring the PA environment of health care settings, including …