Physiology Commons^™

Cellular Mechanisms Underlying Myogenic Reactivity In Isolated Arterioles, Hui Zou

Theses and Dissertations in Biomedical Sciences

The myogenic reactivity provides one of the principal mechanisms for blood flow autoregulation. The aims of the performed studies described in this dissertation were to test the role of [Ca²⁺]_i and MLC phosphorylation in arteriolar myogenic reactivity and further examine the source(s) of activator Ca²⁺ required to initiate and maintain myogenic vasoconstriction. In addition, the possible underlying mechanism of contractile protein expression was also addressed.

These studies used male Sprague Dawley rats of 200 ~ 350 grams body weight. Experiments were carried out using rat cremaster first order arterioles and mesenteric vessels. Gel electrophoresis and immunoblotting …

Is There A Difference In Cortical Representation Between Dominant And Non-Dominant Arm Muscles Of Elite Badminton Players?, Dylan J. Edwards

Theses : Honours

Training for sport involves the development of skill and coordination. The physiological changes associated with skill acquisition are complex and at present poorly understood. One of the areas in the central nervous system thought to be involved with skill acquisition is the cerebral motor cortex where localised areas are responsible for controlling specific muscle groups. Learning or improving a motor skill may require reorganisation of the cortical areas controlling relevant muscles to accommodate the new skill. To test this idea we studied a group of elite badminton players that were highly skilled in their dominant playing arm. Transcranial magnetic stimulation …

Dexamethasone And Insulin Regulation Of Tumor Necrosis Factor And Interleukin 6 Production During Septic Shock, Elisabeth Lilli Hahn

Dissertations

No abstract provided.

A Comparison Of Isokinetic And Isotonic Predictions Of A Functional Task, Mitchell L. Cordova

All-Inclusive List of Electronic Theses and Dissertations

Controversy still exists regarding the use of isokinetic and isotonic exercise in rehabilitation of the injured athlete. Many studies have compared these two types of training methods on various strength measures and functional activity, but have focused on open kinetic chain training. The purposes of this investigation were to determine: 1) which form of closed kinetic chain training, isokinetic or isotonic, would produce the greatest increase in one-legged jump reaction force; and 2) which training method most accurately predicts peak force produced during a one-legged jump. Forty-two legs from 21 female volunteer subjects were used. Each subject had her dominant …

Mechanisms Of Retinal Ganglion Cell Development In The Rhesus Macaque, Thomas C. Steineke

Loma Linda University Electronic Theses, Dissertations & Projects

At present, no effective treatments are known for many common neurological problems. For instance, degenerative diseases and central nervous system injuries are two examples of conditions for which few treatment options exist. Studying how neurons develop, and how they establish and maintain connections may provide important insights into potential treatment modalities. To this end, retinal ganglion cell structural development was studied in the fetal rhesus macaque ranging in age from embryonic day (E)60 to El65 (gestation is 165 ± 2 days). Horse radish peroxidase (HRP) retrograde labeling techniques were used to investigate changes in retinal ganglion cell structure during fetal …

Mechanism Of Action Of Pentobarbital Induced Attenuation Of Vascular Smooth Muscle Contraction, Michael R. Samardzija

Loma Linda University Electronic Theses, Dissertations & Projects

Pentobarbital (PB) vasodilates dog mesenteric and cerebral arteries precontracted with KC1, PGF_2α, caffeine or norepinephrine. It is postulated that PB causes this dilation by reducing Ca²⁺ influx as a non-specific Ca²⁺ channel blocker, or decreasing intracellular Ca²⁺ release. We examined PB effects on intracellular Ca²⁺ release (ICR) and extracellular Ca²⁺ influx (ECI) by stimulating Sprague-Dawley rat tail artery rings with either 100 mM KC1, 50 uM phenylephrine (PE), or two different electrical field stimulation (EES) parameters: tetrodotoxin (TTX; 1 uM) sensitive, or perivascular nerve, (NEFS) stimulation (10 Hz, 0.3 ms, 50 V, 30 …

Cardiovascular, Thermoregulatory, Metabolic And Performance Responses To Repeated Ultraendurance Cycling, Bart E. Drinkard

Human Movement Studies & Special Education Theses & Dissertations

The purpose of this study was to describe physiological and performance responses in six highly trained cyclists during four days of repeated ultraendurance cycling. Each subject raced in four consecutive 100 mile per day time trials using their own bicycles mounted to a computerized ergometer. The race course profile consisted of rolling terrain with simulated gradients of minus five to ten percent. Body weight was measured prior to each time trial. Total performance time and fluid intake for each time trial were recorded. All other data were measured at ten mile intervals during each 100 mile time trial. Means for …

Sensory Information And The Perception Of Cold-Induced Pain, Stephen S. Streator

All-Inclusive List of Electronic Theses and Dissertations

Specific terms are often used to describe the pain athletes will experience during cold treatments. It is not clear whether providing athletes with such sensory information will decrease their perceived pain during treatments. The purpose of this study was to determine if subjects' perception of cold-induced pain could be influenced by the type of information provided before treatment, such as "pain will be excruciating" or "pain will be minimal. 11 Ninety Division I intercollegiate athletes were randomly assigned to one of five groups: traditional terms (cold, burning, aching, numbness); high level (freezing, crushing, pounding, heavy), medium level (cold, gnawing, pulsing, …

Short And Long Term Effects Of Proton Microbeam Irradiation : In The Lateral Geniculate Nucleus Of Felis Domesticus, Chad Sherwood Reder

Loma Linda University Electronic Theses, Dissertations & Projects

Little is known of the effects of proton irradiation on neural tissue. A 1.0 mm microbeam was used on the cat lateral geniculate nucleus (LGN) to quantify the short term (< 3 months) and long term (< 9 months) effects of radiation damage. The LGN is a large structure with well defined afferent, efferent, and receptive field properties.

Electrophysiological and histological techniques were used to examine the effects of the microbeam at 60, 40, and 16 Gy, administered as a single bolus. Recordings of light evoked responses in the LGN were obtained using microelectrodes in nine animals within 12 weeks of irradiation, and 6 animals within 36 weeks of irradiation. Receptive fields were mapped onto a tangent screen using standard receptive field techniques. Histological measures included afferent …

Circadian Clock Locus Frequency: Protein Encoded By A Single Open Reading Frame Defines Period Length And Temperature Compensation., Benjamin D. Aronson, Keith A. Johnson, Jay C. Dunlap

Dartmouth Scholarship

The frequency (frq) locus encodes a key component, a state variable, in a cellular oscillator generating circadian rhythmicity. Two transcripts have been mapped to this region, and data presented here are consistent with the existence of a third transcript. Analysis of cDNA clones and clock mutants from this region focuses attention on one transcript encoding a protein. FRQ, which is a central clock component: (i) mutations in all of the semidominant frq alleles are the result of single amino acid substitutions and map to the open reading frame (ORF) encoding FRQ; (ii) deletion of this ORF, or a frameshift mutation …

An Intramural, Tension-Modulating Reflex In The Rat Caudal Artery, Greg G. Geary

Loma Linda University Electronic Theses, Dissertations & Projects

Electrical field stimulation (EES) of preconstricted arteries causes relaxation. This relaxation is of either neuronal, vascular smooth muscle, and/or endothelial origins. We have shown that EFS-induced relaxation of intact, phenylephrine (PE) preconstricted rat tail artery (RTA) rings was dependent upon the extracellular concentration of Ca++. Inhibiting either nitric oxide (NO) synthesis with N-nitro-L-arginine methyl ester (L-NAME), or the synthesis of cyclic guanosine monophosphate (cGMP) with methylene blue (MB) reduced the EFS-induced relaxation. In addition, inhibition of K_Ca++-dependent hyperpolarization with tetraethylammonium (TEA), or K_ATP hyperpolarization with BaCl₂ or glibenclamide also reduced EFS-induced relaxation. L-arginine reversed the effect …

Inhibition Of Nnk Mutagenesis And Metabolism By Chemopreventive Phytochemicals, Cecil Henry Miller

Loma Linda University Electronic Theses, Dissertations & Projects

Approximately one third of all cancer deaths in the United States can be linked to the use of tobacco products. Cessation of smoking is not always an effective prevention method, especially since nicotine is so addictive. For those individuals who continue to use tobacco products, chemoprevention may be an alternative to reduce their cancer risk. We have investigated the chemopreventive efficacy of five phenolic (catechin, ellagic acid, escletin, esculin and propyl gallate) and five non-phenolic (capsaicin, silymarin, diallyl sulfide, tannic acid, and d-limonene) phytochemicals on tobacco-specific nitrosamine (NNK)-induced mutagenesis and NNK metabolism. In the mutagenesis studies, Salmonella typhimuriumstrain TA1535 …

Summer Activity Cost Of Eared Grebes At Mono Lake, Hugh I. Ellis

Biology: Faculty Scholarship

No abstract provided.

Possible Presence Of Calcium Channel Blocker(S) In Rubia Cordifolia: An Indigenous Medicinal Plant, A H. Gilani, K H. Janbaz, M Zaman, A Lateef, A Suria, H R. Ahmed

Department of Biological & Biomedical Sciences

Crude extract of Rubia cordifolia (RC) was tested in isolated tissue preparations for its possible calcium channel antagonistic activity. RC suppressed the spontaneous contractions of guinea-pig atria, rabbit jejunum and rat uterus in a concentration dependent manner (0.1-3 mg/ml). In rabbit aorta, it inhibited norepinephrine (10 microM) and KCl (80 mM) induced contractions. Replacement of physiological salt solution with calcium free solution abolished the spontaneous movements of rabbit jejunum. However, addition of calcium (25 micrograms/ml) in the tissue bath restored the spontaneous movements. When the tissues were pretreated with plant extract (1 mg/ml) or verapamil (0.5 microgram/ml), addition of calcium …

Multiple Modes Of Asexual Reproduction By Tropical And Subtropical Sea Star Larvae: An Unusual Adaptation For Genet Dispersal And Survival, William Jaeckle

Scholarship

Sea star larvae (Echinodermata: Asteroidea), collected from the subtropical Northwest Atlantic Ocean, exhibited three distinct modes of asexual reproduction. A number of different bipinnariae and brachiolariae reproduced by paratomous cloning of the posterolateral arms. This morphogenesis was identical to that of larvae assignable to the genus Luidia. A second mode of asexual reproduction involves the autotomization of an anterior portion of the preoral lobe. Primary larvae with preoral lobes of varying sizes and free-swimming preoral lobes of various stages of morphological development were simultaneously collected. The free-swimming preoral lobes developed complete digestive systems and ultimately assumed the form of …

Rates Of Energy Consumption And Acquisition By Lecithotrophic Larvae Of Bugula Neritina (Bryozoa: Cheilostomata), William Jaeckle

Scholarship

Lecithotrophic larvae of the cheilostome bryozoan, Bugula neritina (L.), lose metamorphic competence 12 to 24 h after release from the maternal zooid. The high respiration rate of newly released larvae (mean=306.3 pmol O₂ larva^-1 h^-1, range= 149.3 to 466.6, n=18 trials, 22.5 °C) from adults collected at Link Port, Fort Pierce, Florida during the winter/spring of 1990-1991 reflects their active swimming behavior. The average energy con¬tent per larva was 15.24 mJ (range: 13.35 to 20.17 mJ ind^-1, n=5 groups). If all cells have an identical energy content and metabolic rate, then 2 and 20% …

Frequency Of Attainment Of Plateau In Maximal Oxygen Consumption In Differentially Trained Athletes, Jeffrey Michael Seda

Masters Theses

A plateau in oxygen consumption during exercise testing has been considered a requisite indicator of achievement of true maximal oxygen consumption. The wide range of reported percentages of subjects revealing a plateau (7 to 80 percent) indicates that closer analysis of factors that may influence plateau attainment is necessary. This study examined the frequency of plateau attainment in two groups of differentially trained subjects. One group (TR) of 12 males (ages 18-36) were trained runners and the other group (WL) of 12 males (ages 18-31) consisted of trained weight lifters. The subjects participated in a series of maximal exercise tests …

The Effect Of High Intensity Exercise Training Verses Low Intensity Exercise Training On Fractionated Plasma High-Density Lipoprotein Cholesterol, Teresa L. Spate

Masters Theses

Exercise training is thought to result in an elevation of high-density lipoprotein (HDL) and the cardioprotective subfraction HDL{dollar}\sb2{dollar}. Twenty-five healthy women (39 {dollar}\pm{dollar} 7.8 yrs; 70 {dollar}\pm{dollar} 14 kg) walked two miles three times per week for 12 weeks to examine the effect of exercise intensity on the HDL profile. The L.I. group (N = 12) walked at 60% of the heart rate reserve (HRR) and the H.I. group (N = 13) walked at 80% HRR both maintaining the prescribed distance and frequency. A 22% increase in total HDL (from 32 {dollar}\pm{dollar} 6 to 39 {dollar}\pm{dollar} 8 mg/dl) and a …

Can Critical Power Predict And Monitor Swimming Performance?, Michelle L. Stoppenhagen-Noll

Masters Theses

The purpose of this study was to determine if critical power (CP) can be used to predict and monitor swimming performance. Fifteen female collegiate swimmers from Eastern Illinois University volunteered as subjects for this study. CP was measured on an arm ergometer. Freestyle performances in the 50 and 100 yard distances were also measured. All three tests were measured both pre- and post-season. Results indicated that CP can predict performance in the 50 and 100 yard freestyle swims. Those with higher CP will swim faster. CP can monitor improvement in 50 yard times. CP is not a good indicator of …

Effects Of Portuguese Man-Of-War (Physalia Physalis) Venom On Isolated Rabbit Atria, Wayne R. Bonlie

Loma Linda University Electronic Theses, Dissertations & Projects

The cardiac effects of Portuguese man-of-war venom were studied using isolated atria from rabbits. Venom added (7.1 µg protein/ml) to the bath solution stimulates heart rate 120% (P < 0.01) and increases contraction amplitude 308% (P < 0.001). Both effects are dependent on bath concentrations of venom and calcium. The increase in contraction amplitude is significantly attenuated by diltiazem (0.8 µM) and atenolol (10 µM). Atenolol, a β1-adrenergic antagonist, completely blocks the increase in heart rate. Dantrolene (10 µM) did not significantly block the venom's effects. Ryanodine binding increases in the presence of venom showing that the venom is not in competition for calcium channels on the sarcoplasmic reticulum. These results suggest that the venom acts on the sarcolemma to increase calcium permeability, thereby causing an increase in contraction amplitude and possibly causing β1-adrenergic stimulation.

The Effects Of Luminance Boundaries On Color Perception, Richard E. Kronauer, Charles F. Stromeyer Iii, Alex Chaparro

Publications

The luminance and red-green chromatic detection mechanisms respond to, respectively, the sum and difference of the long-wave (L) and middle-wave (M) zone contrast signals. The most-detectable stimulus is not a small patch of luminance drifting grating, as suggested by others, but rather a small, foveal red-green chromatic flash. Even at the smallest test size examined, 2.3' diameter, the red-green mechanism i~s more sensitive than the luminance mechanism, which has profound implication for visual physiology. When a suprathreshold luminance flash (a pedestal) occurs coincidentally with a red-green chromatic flash, detection of color is facilitated ~2-fold, regardless of spot size, as shown …

A Comparison Of Three Cam Profiles As Measured By Emg And Angular Displacement, Elizabeth Grace Ann Hood

Human Movement Studies & Special Education Theses & Dissertations

The purpose of this study was to determine if variations in cam profiles cause differences in muscle contraction as measured by surface EMG, knee joint angular displacement, and torque. There were seven hypotheses tested. The ten subjects were adult male volunteers (18-24 years) who participated in a counterbalanced treatment design study testing three variously shaped cams over five lifting tests. The results indicated that for the EMG data, the cam and lifts effect had significant Wilk's values. For the cam effect the consistent cam had the highest millivolt value. For the lift effect, the pre 1 rep max had the …

On The Relative Importance Of Floral Color, Shape, And Nectar Rewards In Attracting Pollinators To Mimulus, Steven D. Sutherland, Robert K. Vickery Jr.

Great Basin Naturalist

Pollinator preferences were observed for the six species of section Erythranthe of the genus Mimulus using greenhouse-grown plants placed in a meadow in the Red Butte Canyon Natural Area, Salt Lake County, Utah. The principal pollinators were hummingbirds and bumble bees. Hummingbirds preferred the species with the most reflexed tubular flowers regardless of color, whereas bumblebees preferred pink. lavender, or yellow flowers to red flowers regardless of shape. Results for the six species were confirmed by observations of F₂ hybrid recombinant plants selected such that flower color could be held constant and flower shape varied and vice versa.

Thymic Peptide Modulates Glutathione Redox Cycle And Antioxidant Enzymes In Macrophages, Choon Sil Park

Loma Linda University Electronic Theses, Dissertations & Projects

The effect of a 6-kDa thymic peptide (TP) on the oxidative burst of a murine macrophage cell line J774 was determined. TP (12.5-200 μg/ml) was incubated with 5 x 10⁵ J774 cells at 37° C and 5% C0₂ for 18 h and oxidative burst was triggered by zymosan; chemiluminescence was amplified by luminol and measured in an automated luminometer. TP exhibited a concentration-dependent inhibition of oxidative burst. To study the mechanisms involved in TP’s inhibition of oxidative burst, its effect on the glutathione (GSH) redox cycle, GSH biosynthesis, and antioxidant enzymes was investigated. TP was shown to increase …

Relationship Between Intracellular Ph And Calcium Uptake In The Skeletal Muscle During Sepsis, Gin Mo

Master's Theses

No abstract provided.

Ultrastructure Of The Coeloms Of Auricularia Larval (Holothuroidea Echinodermata): Evidence For The Presence Of An Axocoel, E. J. Balser, E. E. Ruppert, William Jaeckle

Scholarship

A hallmark feature of echinoderm larvae is the development of the left anterior coelom. This coelom, called the axohydrocoel, consists of the morphologically distinct, but undivided, left axocel and hydrocel. The axocoelic portion forms a duct that opens to the exterior via a pore on the dorsal surface of the animal. Holothuroid larvae are thought to lack an axocoel, but develop an anterior coelom, duct, and pore that are regarded as parts of the hydrocoel. New ultrastructural data, however, show that holothuroid auricularia larvae possess an axocel and hydrocel united together into an axohydrocoel. During development the anterior coelom consists …

Microzooplankton In The Lower Chesapeake Bay, And The Tidal Elizabeth, James, And York Rivers, Gyung-Soo Park, Harold G. Marshall

Biological Sciences Faculty Publications

Results of a one year study in the lower Chesapeake Bay and three tidal rivers indicate an abundant microzooplankton population, with a mean concentration of 4,231.1/Liter. The most abundant components are the non-loricate ciliates (2,518.2L, 59.5% of the annual total) and tintinnids (1,400.1/L 33.1%). In lesser abundance were the rotifers (191.4/L) and nauplii larvae (121.7/L). Seasonal abundance maxima were highest in summer, followed by fall, spring and winter.

Seasonal Relationships Between Phytoplankton Composition, Abundance, And Primary Productivity In Three Tidal Rivers Of The Lower Chesapeake Bay, Harold G. Marshall, Kneeland K. Nesius

Biological Sciences Faculty Publications

The seasonal abundance and successional patterns of phytoplankton, including autotrophic picoplankton, are compared to spring, summer, and fall primary production maxima that occurred in three tidal rivers. The tidal freshwaters were dominated by diatoms, chlorophytes, and cyanobacteria during a late spring through early fall period of maximum growth. In contrast, downstream assemblages were dominated by estuarine diatoms, dinoflagellates, and cryptomonads which developed spring pulses and a protracted summer-fall maximum. Autotrophic picoplankton produced a major summer pulse at all river stations with reduced abundance during other seasons. The mean annual productivity rates for the tidal James, Rappahannock, and York rivers were …

An Electromyographic Study Of Forward Vs Retrograde Stair Climbing On The Stairmaster 4000 Pt Machine, W. Lynette Rasmussen Thornburgh

Masters Theses

The purpose of this study was to investigate, through electromyography, whether forward or retrograde stair climbing on the StairMaster 4000 PT machine demonstrates a greater muscle contraction duration, differences in intensity of muscle contractions, or variation in initiation of muscle contractions. The muscles examined were the Rectus Femoris, Vastus Medialis, and Biceps Femoris. A gender difference was also evaluated.

Twenty-one subjects apparently healthy volunteered for this study. There were two groups of ten male subjects and eleven female subjects. Subjects were assigned to subgroups according to gender. The subgroups determined which position the subject was tested in first.

The descriptive …

Voltage Clamp Analysis Of Latent Pacemaker Cells Isolated From Cat Right Atrium, Zhengfeng Zhou

Dissertations

No abstract provided.