Because of the aerobic nature of cellular metabolism in mammalian organisms, a continuous supply of oxygen is necessary to maintain normal physiological function. As organisms age, their metabolic rates generally decline and there are accompanying alterations in the structure and function of the microcirculation, as this part of the cardiovascular system is especially important for oxygen exchange. The overall Oxygen Transport System can be considered as being composed of two complementary components: one for Oxygen Demand and one for Oxygen Supply. The purpose of the current work is to describe the age-dependent changes in both oxygen demand and oxygen supply at the level of the microcirculation, using intravital microscopic observations of the rat spinotrapezius muscle, along with optical techniques to delineate the structural, hemodynamic and oxygenation variables needed to characterize the Oxygen Transport System in this tissue. A summary of the findings is that basal oxygen consumption gradually declined with age (from 2 to 12 months) and there were corresponding decreases in tissue blood flow, blood hemoglobin concentration and capillary surface area for oxygen exchange, so that oxygen supply and demand were generally well-matched.

This long-standing nature versus nurture debate is cited in behavioral and physical expressions of disease dysfunctions, resiliencies, and recovery. Their purposes are noted both in scientific pursuits as well as literature. This discourse has been particularly intense in the fields of psychology, psychiatry, and biology where there is a long history of scientists’ attempts to disprove or discredit others’ intellectual and professional measures. Interestingly, recent advances in the neurosciences and genetic technologies have brought these fields closer together with a new focus – the interactional relationship between nature and nurture – epigenetics.

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on January 5, 2010). Thesis advisor: Paul J. Fadel. "December 2009" Includes bibliographical references.

Tick proteins functioning in vital physiological processes such as blood meal uptake, digestion and reproduction are potential targets for anti-tick vaccines, since vaccination could disrupt these essential functions and ultimately affect tick survival. In this study we identified metzincin metalloproteases from R. microplus, the world’s most economically important external ectoparasite of cattle, as potential vaccine candidates since they are implicated to be essential to blood-cavity formation, bloodmeal digestion and reproduction in ixodid ticks. A vaccine derived from a single member of such a large family pose the obstacle of redundancy within the family, that may allow the function of the targeted family member to be taken up by other family members. Therefore the aim of this study was not only to focus on the physiological importance of each metzincin transcript, but also to investigate the differential gene expression network between the different metzincin family members. Eight transcripts encoding proteins containing the characteristic metzincin zinc-binding motif HEXXHXXG/NXXH/D and a unique methionine-turn were identified from native and in-house assembled R. microplus Expressed Sequence Tag databases. These were representative of five reprolysin-like and three astacin-like metzincin metalloproteases. Reverse transcription-PCR indicated that the reprolysins were most abundantly expressed in the salivary glands, whereas the astacins were most abundant in the midgut and ovaries. In vivo gene silencing utilizing RNA interference, was performed to assess a possible phenotype in silenced adult female R. microplus ticks during blood feeding and reproduction. RNAi against two reprolysins and one astacin significantly affected average egg weight as well as the oviposition rate. Moreover, integrated real time-PCR studies revealed an extensive cross organ network between the R. microplus metzincin transcripts, supporting the use of a combinatorial metzincinbased anti- R. microplus vaccine targeting multiple members of the large metzincin clan simultaneous. To conclusively evaluate the vaccination potential of the three identified metzincin candidates, the immunogenicity and protective properties of the recombinant proteins needs to be determined. Due to metalloproteases destructive activity and characteristics such as cysteine rich domains, only selected domains of the three candidates were expressed, using a cost effective Eshericia coli based expression system. Finally, the ability of each successfully expressed domain to elicit an immune response and serve as a protective antigen against R. microplus will be screened during vaccination trials in cattle. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Biochemistry / unrestricted

Migraines are recurrent debilitating headaches that predominately afflict young women. The pathophysiology of migraines is still not well understood but is related to neurovascular dysfunction. Meningeal blood vessel dilation, extravasation of pro-inflammatory cytokines and activation of trigeminal afferent neurons promote migraine generation. Serotonin (5-HT) is an endogenous vasoactive peptide with diverse physiology. In meningeal blood vessels, serotonin causes vasoconstriction, however in coronary arteries, serotonin causes both vasodilation and vasoconstriction. In diseased coronary arteries, with impaired endothelial function, vasoconstriction predominates. Selective meningeal blood vessel serotonin agonists, termed ‘triptans’, have become the therapy of choice for migraine headaches. However, due to their constrictive effects on the coronary vasculature, triptans are not recommend in patients with known coronary artery disease, patients with greater than one coronary artery risk factor or patients with atherosclerotic cardiovascular disease risk (ASCVD) greater than ten percent. Triptan associated chest pain is a well-known phenomenon. Age, hypertension, dyspepsia, and Raynauds phenomenon are associated with triptan associated chest pain. Hypertension is the strongest risk factor for triptan associated chest pain in males. Although triptan associated chest pain is assumed to be cardiovascular due to its constrictive effect on the coronary vasculature, only a few cases of myocardial infarction, with documented ST elevation and/or troponin elevation, have been reported. Herein we report the case of a male patient with inferolateral ST elevation myocardial infarction, within minutes of receiving subcutaneous sumatriptan for migraine headache. The patient had a normal echocardiogram and electrocardiogram prior to sumatriptan use, and a normal cardiac catheterization afterwards.

This investigation examined the heart rate responses and movement characteristics of experienced footbag net players during singles play. Footbag net is a net/court sport similar to volleyball, but it is played with a footbag (e.g., Hacky-SackTM) using only the feet. In singles footbag net, players are allowed either one or two kicks to propel the footbag over the net. Subjects were 15 males and 1 female, ranging in age from 18- 60 years, with a mean age of 33.6 years. Subjects played two games of singles footbag net using two different scoring systems: "sideout" scoring and "rally" scoring. Mean heart rates were 149.4 bpm for games played under the sideout scoring system and 148.7 bpm for games played under the rally scoring system. Sideout games were 1.2 minutes (~11%) longer than rally games. The mean heart rate responses to competitive play using sideout scoring and rally scoring were not significantly different (p>0.05). For play under both scoring systems, the average exercise intensity--expressed as a percentage of age-predicted maximum heart rate (MHRest)--was 80-81% MHRest. Accelerometer counts accumulated during play were similar for both scoring systems. It is recommended that additional research be conducted to evaluate the extent to which accelerometry may contribute to physiological and metabolic measurements of footbag net competition.

No description available.

<p>An acute bout of exercise causes short-term changes in the immune system in both children and adults. It has been well-established that exercise induces an inflammatory response. Especially in children, cytokines play an important role in balancing anabolic and catabolic processes of growth. Existing evidence suggests cross-talk between inflammation and oxidative stress. Reactive oxygen species are also found to transiently increase in response to exercise, affecting muscle adaptation post-exercise. Characterizing the exercise-induced inflammatory and oxidative stress responses in children compared to adults will start clarifying the transition from the child phenotype to that of an adult. Ten children aged 8-10 and 12 adults aged 19-21 performed 2×30min bouts of continuous cycling, separated by a 6min rest period, at a target work rate of 60% of their maximum aerobic capacity. Blood samples were collected pre-exercise and immediately post-exercise, and analyzed for<strong> </strong>neutrophil count, systemic oxidative and inflammatory markers (tumor necrosis factor alpha, interleukin 6, protein carbonyls, malondialdehyde, elastase), intracellular neutrophil-derived reactive oxygen species (using 3 fluorescent markers detected by flow cytometry), and <em>in vitro</em> production of neutrophil-derived myeloperoxidase and interleukin 8. Compared to the post-exercise increase in absolute neutrophils in men, boys showed no change. However, intracellular neutrophil reactive oxygen species production increased for boys and not for men. Boys also demonstrated higher overall protein carbonyl levels, whereas men showed higher overall malondialdehyde. Both boys and men showed a positive correlation between tumor necrosis factor alpha and elastase, with a steeper slope seen in boys. Although there were other correlations observed in boys and men, no others existed in both. The differences observed in the exercise-induced inflammatory and oxidative stress response may indicate growth-mediated adaptive responses to exercise during childhood development.</p> / Master of Science (MSc)

Hyperhomocysteinemia (hHcys) is a widely known pathogenic factor in the progression of end-stage renal disease (ESRD) and it is also associated with an increased risk for injurious cardiovascular pathologies during ESRD. HHcys is linked to the formation and activation of the NOD-like receptor protein 3 (NLRP3) inflammasome, characterized as a critical early mechanism initiating the inflammatory response. NADPH oxidase (NOX)-derived reactive oxygen species (ROS) mediate the activation of the NLRP3 inflammasome in podocytes in response to elevated levels of homocysteine (Hcys) in vitro and in vivo. However, it remains unknown how NLRP3 inflammasome activation is triggered by NOX. The aim of the present study sought to determine the signaling cascade that triggers glomerular injury and sclerosis during hHcys mediated by Vav2, a guanine nucleotide exchange factor (GNEF). Using both genetic and pharmacological interventions of Vav2, we first tested whether this GNEF is involved in hHcys-induced NLRP3 inflammasome activation in podocytes by its role in activation of the Rac-1-NOX complex. Further, we explored whether pharmacological targeting of Vav2 activation may regulate NLRP3 inflammasome signaling pathway during hHcys-induced glomerular injury. We found that mice with hHcys (on the FF diet) or oncoVav2 (a constitutively active form of Vav2) transfection in the kidney exhibited increased colocalization of NLRP3 with apoptosis-associated speck-like protein (ASC) or caspase-1 and elevated IL-1β levels in glomeruli, indicating the formation and activation of the NLRP3 inflammasome. This glomerular NLRP3 inflammasome activation was accompanied by podocyte dysfunction and glomerular injury, even sclerosis. Local transfection of Vav2 shRNA plasmids significantly attenuated hHcys-induced NLRP3 inflammasome activation, podocyte injury, and glomerular sclerosis. In cultured podocytes, Hcys treatment and oncoVav2 transfection increased NLRP3 inflammasome formation and activation. This NLRP3 activation was inhibited by Vav2 shRNA, associated with reduction of Rac-1 activity and ROS production. Administration of NSC23766, a Rac-1 inhibitor substantially attenuated inflammasome formation, desmin expression and decreased podocin expression in glomeruli of hHcys mice. These results suggest that elevated Hcys levels activate Vav2 and thereby increase NOX activity, leading to ROS production. ROS trigger NLRP3 inflammasome activation, podocyte dysfunction and glomerular injury. Therefore, the present study defines a novel mechanism underlying hHcys-induced NLRP3 inflammasome activation and its progression to ESRD.

Isovaleric Acid (IVA) is a 5-carbon branched chain fatty acid present in fermented foods and produced by the fermentation of leucine by colonic bacteria. IVA activates G-protein coupled receptors such as FFAR2, FFAR3, and OR51E1 known to be expressed on enteric neurons and enteroendocrine cells. We previously reported that the shorter, straight chain fatty acids acetate, propionate and butyrate, differentially affect colonic propulsion; however, the effect of branched chain fatty acids on gastrointestinal motility is unknown. We hypothesize that IVA relaxes smooth muscle in a cAMP/PKA dependent manner by direct action on smooth muscle cells. IVA will also decrease peristalsis and encourage retention of luminal contents. This thesis investigates the effect of IVA on smooth muscle tension and peristaltic activity in isolated colon and individual smooth muscle cells. Colon segments from C57BL/6J mice were placed in a longitudinal orientation in organ baths in Krebs buffer and fastened to force transducers. Segments were contracted with 10 μM acetylcholine (ACh) and the effects of IVA at several concentrations were measured in the absence and presence of Nitric Oxide Synthase inhibitor L-N-nitroarginine (L-NNA), neuronal action potential inhibitor tetrodotoxin (TTX), and adenylate cyclase inhibitor SQ22536. To study individual live cells, mouse smooth muscle was isolated from colon, suspended in smooth muscle buffer, and after contraction with ACh were relaxed with micromolar concentrations of IVA. For peristalsis studies, whole colonic segments isolated from C57BL/6J were catheterized and placed horizontally in organ baths with circulating Krebs buffer. The colon was clamped on the anal end, and a solution (5 μL per mm of colon length) of either Krebs buffer or 50 mM IVA was delivered from the oral end to the lumen. Video of the peristalsis was then analyzed for diameter, changes in diameter, velocity of diameter changes along the length of the colon, normalized to the anatomical changes in the proximal region. IVA in concentrations of 10 mM to 50 mM relaxed the ACh-induced contraction in a sigmoidal fashion. In separate studies, L-NNA nor TTX affected the ability of IVA to inhibit relaxation. SQ22536 inhibited IVA induced relaxation in longitudinal colon compared to vehicle control. In isolated cells, SQ22536 and PKA inhibitor H-89 inhibited IVA-induced relaxation. In peristalsis studies, 50 mM IVA in Krebs buffer changed the character of the peristaltic action by increasing proximal diameter, inhibiting contractions in the proximal end of the colon, and decreasing overall velocity of peristaltic contractions in the proximal region. The data indicate that the branched chain fatty acid IVA causes a concentration-dependent relaxation of colonic smooth muscle that is direct to the smooth muscle and independent of neuronal activity. This relaxation is cAMP/PKA dependent. In addition to the direct relaxation of smooth muscle, intraluminal IVA decreased overall colonic propulsive activity and encouraged retention of the luminal contents. We conclude that the ingestion and production of branched chain fatty acids could affect overall GI motility and is an area for study in dietary and therapeutic control of bowel activity.