An Investigation of the Effect of Chewing on Rhythmic Motor Tasks

Chewing gum and walking has traditionally been cited as the quintessentially difficult dual task, but little is known regarding chewing effects on motor control. The aims of this dissertation include describing chewing patterns across adulthood, describing chewing’s influence on secondary motor tasks, and investigate entrainment patterns of chewing and gait per established patterns of coupled oscillators. Three experiments were conducted to describe chewing patterns and to examine the effect chewing has on other motor tasks, particularly walking, in young and old adults. The first experiment used a metronome to manipulate chewing rates and measured associated gait parameters. This experiment established that chewing affects gait. As chewing speed increases or decreases, step rate also changes accordingly. Tasks such as walking, finger tapping, and simple reaction time all slow with advancing age. This experiment established chewing as a task resistant to neuromotor slowing with age. The second experiment examined the effect of chewing on a variety of secondary motor tasks. This experiment confirmed that chewing interferes with performance of a discrete secondary task, such as reaction time, whereas chewing entrains with cyclic movements, like finger tapping and gait. The final experiment varied the timing of when chewing was initiated to highlight the inherent organization of task influence. This experiment confirmed that chewing consistently impacts gait, but not vice versa. A top-down hierarchy where chewing drives changes in gait was substantiated. The physiological basis for the observed behavior is discussed in terms of coupled neural oscillators, such as the central pattern generators in the hindbrain and spinal cord. The findings from the series of experiments highlights oral sensory information as a potentially novel method of influencing movement patterns throughout adulthood. The functional implications of chewing are paramount to survival, but the connection between the mouth and the legs has not been well documented. Understanding the mechanisms associated with this inimitable relationship whereby the mouth is driving leg motion during gait could lead to innovative rehabilitative techniques for gait training

Análisis del estrés psíquico en colocadores brasileños de voleibol de alto nivel

En el voleibol competitivo de alto nivel, los jugadores frecuentemente se han de enfrentar a situaciones estresantes. Los colocadores, específicamente son los responsables de armar las jugadas y decidir qué jugador atacará, su ejecución depende en muchas situaciones de la actuación de otros jugadores. ésta y otras situaciones pueden predisponer a este jugador a manifestar una reacción negativa de estrés y perjudicar su rendimiento. Este estudio tiene como objetivo principal analizar las situaciones típicas que los colocadores experimentan durante la competición y verificar, los comportamientos más probables adoptados por estos jugadores en las respectivas situaciones. El instrumento utilizado fue el Test de Estrés Psíquico de Voleibol (TEP-V) compuesto de situaciones estresantes típicas para la posición del jugador. Colaboraron en este estudio 33 colocadores de voleibol de alto nivel, participantes de la Superliga 97/98, siendo 19 jugadores de sexo masculino y 14 de sexo femenino, haciendo un total de 79,2% de dicha población. Los jugadores presentaron una edad media de 24,7 anos (+-4,21) y una experiencia en competición de 10,4 anos (+-4,97). Se comprobó que para los colocadores la situación más estresante se caracteriza por la frase el árbitro senala, una y otra vez, una infracción en mis acciones. Se concluyó que la situación de estar en desventaja después del minuto 25 es más estresante para los colocadores, que estar en desventaja antes (p0.001). Colocadores de sexo masculino atribuyen una carga negativa mayor a la mayoría de situaciones típicas. Independientemente de la situación de estrés afrontada, el comportamiento más probable a ser adoptado por los jugadores de sexo masculino y femenino de las diferentes posiciones (colocadores y atacantes) fue, me tengo que tranquilizar.High level volleyball athletes are confronted with stress situations very often. The principal task of the setters is to prepare the stroke, deciding which player will attack, and his performance is influenced, in many situations, by the actions of the other players. Under such conditions, the athlete is subject to a stressful negative reaction, which is prejudicial to his performance. The purpose of this study is to analyse the most probable behaviors applied by the setters in critical competition situations. The Volleyball Psychological Stress Test (VPS-T) containing typical stressful situations for such players was used as the instrument. This test was applied to 33 setters at the Brazilian Superleague, being 19 males and 14 females, which means 79,2% of the total population. They were 24,7 (± 4,21) years old and 10,4 (± 4,97) years of competitive experience. It was verified that for such players, the most stressing situation was «the referee is, over and over, pointing an infraction in my actions». It was concluded that is most stressful for the players a negative score after the 25' minute than before (p<0.01), and males usually attribute more negative charge to the typical situations. Aside of the stress situation, both males and females players, spikers as well as setters, the behaviors of «trying to control myself' is the most probable to be used

Serotype-specific replicating AAV helper constructs increase recombinant AAV type 2 vector production

One of the major limitations of the use of adeno-associated virus (AAV) as a tool for gene therapy is the difficulty in providing sufficient quantities of the virus for pre-clinical and clinical trials. Here, we report a novel approach for amplifying AAV helper functions, which mimics the normal replication of wild type (wt) AAV resulting in a high yield of AAV vectors. Cotransfection of replicating but non-packaging AAV helper constructs in the presence of adenovirus (Ad) produces a high level of Rep and Cap proteins. Yield of AAV2/GFP vector obtained from this helper DNA replication system was approximately 20-fold higher than traditional methods. Molecular analysis suggested that virus yield was associated with capsid protein production. The transfection ratio was optimized using these novel helper constructs, resulting in an additional 2-fold increase in vector yield without presence of replication competent AAV (rcAAV). This strategy supports development of AAV packaging systems that retain normal virus replication capability without helper virus encapsidation

Building a Better Vector: The Manipulation of AAV Virions

This review will focus on research directed at manipulating the virion of adeno-associated virus (AAV) with the goals of circumventing the immune response of the virion, as well as retargeting the virus to specific cell types of interest. The use of five AAV serotypes for addressing questions of Ab neutralization, novel tropism, as well as providing natural templates for targeting by virion modification will be discussed

Characterization of a novel adeno-associated viral vector with preferential oligodendrocyte tropism

No adeno-associated virus (AAV) capsid has been described in the literature to exhibit a primary oligodendrocyte tropism when a constitutive promoter drives gene expression, which is a significant barrier for efficient in vivo oligodendrocyte gene transfer. The vast majority of AAV vectors, such as AAV1, 2, 5, 6, 8 or 9, exhibit a dominant neuronal tropism in the central nervous system. However, a novel AAV capsid (Olig001) generated using capsid shuffling and directed evolution was recovered after rat intravenous delivery and subsequent capsid clone rescue, which exhibited a > 95% tropism for striatal oligodendrocytes after rat intracranial infusion where a constitutive promoter drove gene expression. Olig001 contains a chimeric mixture of AAV1, 2, 6, 8 and 9, but unlike these parental serotypes after intravenous administration Olig001 has very low affinity for peripheral organs, especially the liver. Furthermore, in mixed glial cell cultures, Olig001 exhibits a 9-fold greater binding when compared with AAV8. This novel oligodendrocyte-preferring AAV vector exhibits characteristics that are a marked departure from previously described AAV serotypes

Direct interaction of human serum proteins with AAV virions to enhance AAV transduction: immediate impact on clinical applications

Recent hemophilia B clinical trials using adeno-associated virus (AAV) gene delivery have demonstrated much lower FIX production in patients compared to the high levels observed in animal models and AAV capsid specific CTLs response elicited at high doses of AAV vectors. These results emphasize the necessity to explore effective approaches for enhancement of AAV transduction. Initially, we found that incubation of all AAV vectors with human serum enhanced AAV transduction. Complementary analytical experiments demonstrated that human serum albumin (HSA) directly interacted with the AAV capsid and augmented AAV transduction. The enhanced transduction was observed with clinical grade HSA. Mechanistic studies suggest that HSA increases AAV binding to target cells and that the interaction of HSA with AAV doesn’t interfere with the AAV infection pathway. Importantly, HSA incubation during vector dialysis also increased transduction. Finally, HSA enhancement of AAV transduction in a model of hemophilia B displayed greater than a 5-fold increase in vector derived circulating FIX, which improved the bleeding phenotype correction. In conclusion, incubation of HSA with AAV vectors supports a universal augmentation of AAV transduction and more importantly, this approach can be immediately transitioned to the clinic for the treatment of hemophilia and other diseases

Insertional Mutagenesis of AAV2 Capsid and the Production of Recombinant Virus

The structural genes of adeno-associated virus serotype 2 (AAV2) have been altered by linker insertional mutagenesis in order to define critical components of virion assembly and infectivity. An in-frame restriction site linker was inserted across the capsid coding domain of a recombinant plasmid. After complementation in vivo, recombinant AAV2 viruses were generated and assayed for capsid production, packaging, transduction, heparin agarose binding, and morphology. Three classes of capsid mutants where identified. Class I mutants expressed structural proteins but were defective in virion assembly. Class II mutants generated intact virions that protected the viral genome from DNase, but failed to infect target cells. The majority of these mutants bound the heparin affinity matrix, suggesting that attachment to the AAV primary receptor was not rate limiting. One class II mutant, H2634, assembled virions and bound heparin using only Vp3, indicating that this subunit is responsible for mediating AAV receptor attachment. Finally, class III mutants assembled virions, encapsidated DNA, and infected target cells. Infectivity of these mutants ranged from 5 to 100% of that of the wild-type, demonstrating for the first time the ability to alter capsid proteins without interfering with infectivity. These AAV virions with altered capsid subunits will provide critical templates for manipulating AAV vectors for cell-specific gene delivery in vivo. In summary, the AAV capsid variants described here will facilitate further study of virus assembly, entry, and infection, as well as advance the development of this versatile vector system

Chewing Speed Does Not Follow Typical Patterns of Motor Slowing with Age

Aging adults experience gradual structural changes in nerve and muscle tissues that impair their ability to exploit speed as an effective movement strategy. The aim of the study was to examine whether chewing rates demonstrate a level of age-related neuromotor decline similar to other motor tasks. Fifteen young (20-40 years) and fifteen healthy older adults (60+ years) completed a battery of motor tasks including: walking, finger tapping, simple reaction time, postural sway, and chewing. Gait metrics were collected using a 20-foot pressure-sensitive walkway. All walking was performed at a preferred speed. Participants tapped an accelerometer affixed to a table at a preferred rate. Upper extremity reaction time was recorded by depressing a mouse button with an associated timing mechanism, whereas a similar foot pedal interface was used to measure lower extremity reaction time. Postural sway data was collected using a force plate. Surface electromyography of the masseter was used to record fast(2Hz), slow(1Hz), and preferred chewing rates. Fast and slow chewing rates were set using an auditory metronome which was switched off during recording. Age comparisons for each task were performed using general linear modeling, with additional considerations for chewing speed effects and interactions for the chewing task. The results reveal that older adults demonstrate a general slowing of movement with the exception of chewing speed which appears to be preserved with aging. Regardless of age, preferred chewing rates were nearly identical. Preservation of chewing rates compared to other motor tasks may be due to the difference in anatomical innervation between muscles of mastication and the limbs. Masticatory muscles receive bilateral innervation including ipsilateral and contralateral inputs from the motor cortices, whereas limb muscles receive mainly unilateral innervation from the contralateral cortex. The neural redundancy may preserve chewing rates despite age-related degradation of the system.https://digitalcommons.odu.edu/health_sciences/1009/thumbnail.jp

AAV Biology, Infectivity and Therapeutic Use from Bench to Clinic

Adeno-associated virus (AAV) has been isolated from numerous vertebrate species since 1966. Besides its wide and promiscuous tropism, AAV infection does not result in considerable toxicity or pathogenicity and is capable of achieving adequate and long-term levels of gene transfer, especially following generation of the AAV recombinant variant: rAAV. Due to these properties, rAAV has gained special attention as a viral vector for gene therapy in the last decade. Currently, there are 130 clinical trials taking place worldwide for several diseases testing the safety and efficacy profiles of rAAV. During preclinical and clinical studies, several challenges have arisen in terms of reaching the full therapeutic potential of rAAV, such as efficient delivery of the virus in a targeted and specific manner to a desired tissue. Importantly, the development of immune responses towards the viral capsids poses an obstacle to rAAV applicability in the clinical setting. Numerous approaches have been developed in order to tailor an optimized therapeutic virus for treating specific diseases, including the use of different AAV serotypes or the creation of recombinant capsid variants with distinctive transduction and immunological profiles. This chapter reviews current information on rAAV clinical trials and the potential for combining rAAV platform with other technologies, such as induced pluripotent cells and gene editing