Dissertations / Theses on the topic 'Muscle blood flow'
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Lutjemeier, Barbara June. "Control of muscle blood flow during dynamic exercise : muscle contraction / blood flow interactions." Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/244.
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Monteiro, André Antonio. "Blood flow change in human masseter muscle elicited by voluntary isometric contraction." Stockholm : Kongl. Carolinska Medico Chirurgiska Institutet, 1990. http://catalog.hathitrust.org/api/volumes/oclc/21700760.html.
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Naamani, Randa. "The mechanical effects of muscle contractions of muscle blood flow /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60010.
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To determine whether muscle contractions can increase muscle blood flow independently from metabolic factors, we isolated the diaphragmatic vasculature of 16 anesthetized and mechanically ventilated dogs. Phrenic inflow (Qphr) was controlled with a constant pressure source and the pressure (Pa) was decreased in steps to obtain the pressure-flow relation (P-Q). The vasculture was maximally vasodilated and contractions occurred spontaneously (n = 6) or were induced by twitches (n = 12) or tetanic trains (n = 7). The P-Q relations with contractions were compared to those with vasodilatation alone. With spontaneous contractions, the pressure intercept decreased from 47.35 $ pm$ 17.44 to 33.77 $ pm$ 16.82 mmHg (p $<$ 0.05) and the slope remained unchanged so that at Pa = 100 mmHg, Qphr increased from 36.22 $ pm$ 34.85 to 43.91 $ pm$ 38.22 ml/min/100g (p $<$ 0.05). Flow increased slightly with twitches but not with trains. We also elicited twitches, 12/min and 60/min trains in vascularly isolated gastrocnemius muscles (n = 6) and found no change in flow. In conclusion, the muscle pump has only a small effect on muscle blood flow.
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Harper, Allison Jessica. "Adequacy of Muscle Blood Flow During Handgrip Exercise." University of Toledo / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1260580537.
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Hoy, Andrew James. "Nutritive and non-nutritive blood flow in skeletal muscle." Department of Biomedical Science - Faculty of Health & Behavioural Sciences, 2004. http://ro.uow.edu.au/theses/232.
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The vascular structure of mammalian skeletal muscle has been intensively investigated for the last seventy years. Since the early work of Pappenheimer and Barlow, the existence of a parallel dual vascular pathway has been suggested to explain the differences between total flow and clearance rates of a variety of infused substances. Direct microscopy studies using superficial muscles have shown that the microvascular arterioles have very frequent connections with the capillary modules of the associated connective tissue and adipose tissue within skeletal muscle. In more recent times, Clark and colleagues have identified two vascular pathways according to the opposing actions of two groups of vasoconstricting agents. While all increase perfusion pressure, Type A vasoconstrictors (low dose noradrenaline (Nad), vasopressin, angiotensin II) increase oxygen uptake but Type B vasoconstrictors (serotonin, high dose noradrenaline) decrease hindlimb oxygen consumption. The opposing effects on oxygen consumption are thought to arise from selective vasoconstriction of the mircrovasculature. Type A vasoconstrictors redirect blood into muscle tissue capillary beds (termed nutritive bed) whilst Type B vasoconstrictors redirect blood into the associated connective tissue, adipose and septum capillary beds (termed non-nutritive bed). Many of the previous studies are based on variations of an in situ rat, isolated perfused hindlimb model, having low vascular tone and often with insufficient oxygen carrying capacity to support active metabolism. In vivo, skeletal intramuscular blood redistribution during exercise occurs principally via the release of vasodilatory metabolites and the nervous system. This thesis used a novel in vivo model to test the hypothesis that nutritive and non nutritive blood flow distribution can still be observed under conditions of high vascular tone and oxygen delivery at rest and in metabolically active (contracting) muscle. Utilising the high vascular tone, it also tests the hypothesis that the vascular pathways can be differentiated using vasodilators. Male Wistar rats were anaesthetised with sodium pentobarbital (6mg.100g(superscript �1) i.p.). The right femoral artery was cannulated to supply blood to the left femoral artery (perfused) at a constant flow (basal 1ml.min(superscript �1), contraction 2ml.min(superscript �1) via a pump. Perfused hindlimb pressure was recorded distal to the pump and passive venous return occurred from the left femoral vein to the right external jugular vein. Systemic blood pressure was recorded from the left common carotid artery. Polyethylene cannulae were filled with heparinized 0.9% saline containing 6% w/v dextran70. The left sciatic nerve was isolated and stimulated (5Hz) to produce twitch contraction in the lower hindlimb muscle bundle and developed tension was recorded. Vasoactive drugs (2 constrictor, 8 dilator) were prepared with saline and 0.01% ascorbic acid, and injected into the arterial loop. Blood was sampled from the venous and arterial loops and oxygen consumption determined using the Fick equation. In the autoperfused rat hindlimb, the Type B vasoconstrictor increased perfusion pressure and caused a significant decrease in basal hindlimb oxygen consumption, however during muscle contraction this effect on oxygen consumption was diminished. The Type A vasoconstrictor had no significant effect on hindlimb oxygen consumption during significant increases in perfusion pressure. Eight vasodilators with a variety of mechanisms of action were screened at rest but none were observed to decreases hindlimb oxygen consumption in a fashion similar to Type B vasoconstrictors. Increases in oxygen availability at rest via increased nutritive flow by noradrenaline and vasodilator infusion had no effect upon basal metabolic rate. Therefore, during adequate oxygen delivery, increased availability has no effect upon metabolic demand. Isoprenaline and histamine significantly increased hindlimb oxygen consumption during the contraction protocol, whilst there was no significant effect observed at rest. It can be concluded that selective vasoconstriction metabolites can overcome exogenous vasoconstriction. These results confirm the possible existence of a dual vascular pathway however blood flow redistribution via vasodilation is likely determined by the locale of vasodilator release rather than differences in receptor distribution.
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Hughes, William Edward. "Dynamics of skeletal muscle blood flow and vasodilation with age." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6142.
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Aging is associated with attenuated blood flow and vasodilator responses during rhythmic exercise. Older adults also demonstrate attenuated blood flow and vasodilator responses following single skeletal muscle contractions (contraction-induced rapid onset vasodilation, ROV) within the forearm. These age-associated attenuations within the forearm have been demonstrated to be a result of endothelial and neural mechanisms. The objective of this research was to examine: 1) whether age-associated attenuations within the forearm are from mechanical factors; 2) whether age-associated attentions in ROV are present within the leg, as well as explore potential mechanisms for these age-associated attenuations in ROV; 3) examine whether aging is associated with a slower rate of adjustment in vasodilation (vasodilator kinetics) during rhythmic exercise preceding steady-state exercise; and 4) examine approaches to ameliorate age-related attenuations in blood flow and vasodilation within the leg across the entire exercise transient (onset to steady-state).
The novel findings of this research are that 1) age-associated attenuations in ROV within the forearm are independent of mechanical factors; 2) older adults demonstrate attenuated ROV responses within the leg; 3) age-related attenuations in ROV within the leg are not explained by enhanced sympathetic adrenergic vasoconstriction; 4) older adults exhibit prolonged vasodilator kinetics preceding steady-state exercise; and 5) when examined in a cross-sectional design chronic exercise training improves ROV, vasodilator kinetics, as well as steady-state blood flow and vasodilator responses in older adults; 6) acute supplementation with dietary nitrate fails to exert any effect on blood flow and vasodilator responses during any domain of exercise. Collectively, this work establishes that aging is associated with reductions in blood flow and vasodilation across the entire exercise transient (onset to steady-state) within the leg, which is offset by chronic exercise training. Mechanistically, the current data suggests that mechanical and sympathetic factors do not explain age-related reductions in ROV in the arm and leg, respectively. Furthermore, acute supplementation of dietary nitrate does not impact leg blood flow and vasodilator responses in older adults during any domain of the exercise transient.
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Ferreira, Leonardo Franklin. "Dynamics of muscle blood flow, O[subscript2] uptake and muscle microvascular oxygenation during exercise." Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/201.
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Bushell, Alison Jayne. "Protection of skeletal muscle against ischaemia and reperfusion induced damage." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365914.
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Stacy, Mitchel R. "The Effect of Eccentric Exercise-Induced Muscle Injury on Vascular Function and Muscle Blood Flow." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302229144.
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Sandberg, Margareta. "Acupuncture : the effects on muscle blood flow and aspects of treatment in the clinical context /." Linköping : Univ, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/med867s.pdf.
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McGrattan, Peter David. "Insulin receptor studies in ruminant liver, adipose and skeletal muscle tissue." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268235.
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O'halloran, John Francis. "The Hypertrophic Effects of Practical Vascular Blood Flow Restriction Training." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5087.
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Practical blood flow restriction training is a new training technique that has the potential to increase muscular hypertrophy and muscular strength while allowing practitioners to train with lighter loads (20-30% of 1-RM). Through the use of elastic knee wraps, the limbs can be restricted using a perceived pressure scale. The comparison of practical blood flow resistance training with traditional, non-blood flow restricted resistance training and its effects on muscular hypertrophy and strength has not been investigated.
Twenty-one resistance-trained males participated in a 4-week training program and were randomly assigned to one of two groups: Practical BFR training (BFR; n = 10) and Resistance training (RT; n = 11). The primary difference between the groups was the BFR group performed approximately 62% of all sets blood flow restricted at 20-30% of 1-RM while the RT group performed all sets at an intensity of > 70% 1-RM in a traditional manner (non-blood flow restricted). Perceived pressure for blood flow restriction in the BFR group for the arms and legs was 7 out of 10. Workouts for both groups were similar and consisted of whole body routines ~3 days/week. A 2x2 repeated measures ANOVA was used to assess group, time, and group by time interactions. Statistical significance was set to p ≤ 0.05.
There was a no difference in total lifting volume with the BFR group achieving a total lifting volume that was 11% less than the RT group. There was a main effect for time for biceps cross-sectional area (p = 0.004), thigh girth (p = 0.002), bench press 1RM (p = 0.001) and leg press 1RM (p < 0.001). Specifically, BFR improved from 220.5 ± 65.1 to 235.0 ± 50.6 pounds and from 822 ± 135.9 to 952.5 ± 168.9 pounds in the bench press and leg press, respectively. The RT improved from 245.9 ± 60.9 to 257.7 ± 53.5 pounds and from 780.5 ± 192.4 to 957.3 ± 213.4 pounds in the bench press and leg press, respectively. No interaction effects were observed for all hypertrophy and strength variables.
4-weeks of practical blood flow restriction training is as effective for inducing maximal bench press and leg press strength, as well as biceps muscle size and thigh muscle size, as compared to traditional resistance training, despite training at low percentages of subjects 1-RM.
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Trangmar, Steven John. "Circulatory limitations to exercise capacity in humans : the impact of heat stress and dehydration on brain and muscle blood flow and metabolism." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/10609.
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Heat stress and dehydration pose a severe challenge to physiological function and the capability to perform physical work. There is, however, limited knowledge on the regional haemodynamic and metabolic responses to strenuous exercise in environmentally stressful conditions. The primary aim of this thesis was to examine whether dehydration and heat stress compromise brain, muscle and systemic blood flow and metabolism, and whether depressed brain and muscle oxygen delivery underpin reduced exercise capacity during graded incremental and prolonged exercise. This thesis makes an original contribution to the knowledge by showing for the first time that dehydration markedly accelerates the decline in cerebral blood flow during maximal incremental (Chapter 4) and prolonged sub-maximal exercise (Chapter 5) in the heat. Cerebral metabolism, however, is preserved by compensatory increases in substrate extraction. Falling carbon dioxide tension underpinned the decline in CBF. However, a distinct regional distribution of blood flow across the head was observed, suggesting that different mechanisms are responsible for the regulation of regional blood flow within the head. A reduced cerebral metabolism is therefore an unlikely factor explaining the compromised exercise capacity in physiologically stressful hot environments. Rather, restrictions in active muscle blood flow and oxygen supply, which are not apparent during sub-maximal exercise, may explain the reduced maximal aerobic power in heat stressed conditions. For the first time we have manipulated skin and core temperature to show that combined internal and skin hyperthermia reduces maximal aerobic power in association with restrictions in limb, brain and systemic blood flow and skeletal muscle metabolism (Chapter 6). Overall, the findings of the present thesis provide novel information on how circulatory limitations across contracting skeletal muscle, brain and systemic tissues and organs might underpin the impairment in exercise capacity in physiologically taxing environments evoking significant dehydration and hyperthermia.
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Schwagerl, Peter J. "The effects of ascorbic acid on skeletal muscle blood flow in aged rats." Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/4141.
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Kruse, Nicholas T. "Blood Flow and Oxygenation Dynamics as a Result of Human Skeletal Muscle Stretching." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430471839.
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Violette, Victoria Ann. "Acute Muscle Responses to Blood Flow Restriction Exercises in Post Bariatric Surgery Patients." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/9178.
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Purpose: The purpose of this study was two-fold: (1) determine if muscle activation was greater in a BFR exercise condition compared to non-BFR exercise condition using MRI T2 mapping, and (2) determine if the muscle activation for both BFR and non-BFR exercise conditions differs between postbariatric surgery individuals and individuals in 2 control groups. Methods: Three groups participated: (1) a normal-BMI group, (2) a postbariatric surgery group, and (3) a matched group for the surgery individuals. Ultrasound imaging was used to find the optimal BFR pressure for each participant. All participants participated in both BFR and non-BFR exercises. Using a 3-Telsa MRI, a T2 map was imaged prior to and immediately following exercise. Analyses included within-group-across-condition comparisons and within-condition-across-group comparisons. The outcome variable of interest was the change in muscle activation determined via T2 mapping. Results: There was no statistical difference in the increase in muscle activation between BFR and non-BFR exercise conditions (p-value range 0.1091 to 0.9166). When comparing groups across conditions, we found that the surgery group elicited a significantly greater increase in activation compared to the normal-BMI group in every condition (p-value range 0.0014 to 0.0217) and in several muscles when compared to the matched group (p-value range 0.0060 to 0.0311). Other muscles compared to the matched group were not significantly different (p-value range 0.0683 to 0.129). No difference was found between the control groups (p-value range 0.2041 to 0.9557) in muscle activation for either condition. Conclusion: These results did not suggest a difference between BFR exercise and non-BFR exercise for the calf-raise protocol. Postbariatric surgery patients elicited an equal muscle activation response in some conditions and a greater muscle activation response in others when compared to both control groups. Further research is needed to determine whether a greater intensity or duration of exercise is needed to elicit an acute response to BFR and what factors are contributing to the increased muscle activation seen in the postbariatric surgery group.
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Patterson, Stephen. "Low load resistance training with blood flow restriction : adaptations and mechanisms in young and old people." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8797.
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Low load resistance training (LLRT) with blood flow restriction (BFR) is a novel form of exercise that has been demonstrated to increase muscle mass and strength. Combined with the fact that as individuals age they lose both of these parameters, LLRT with BFR has been put forward as a method to help reverse/prevent the associated sarcopenia of ageing. This research investigated the effect the effect of LLRT with BFR on muscle strength firstly in younger people and then an older population group following 4 weeks of training. Muscle function measurements of young and old people included dynamic strength, identified as one repetition maximum (1 RM), isometric strength and isokinetic torque at a range of velocities (0.52 2.09 rad.s-1). Vascular adaptations were also measured using venous occlusion plethysmography to assess rest blood flow (Rbf) and post occlusive reactive hyperemia (PObf). The mechanisms behind any adaptations were measured following acute responses of plasma hormones and growth factors (cortisol, growth hormone (GH), insulin like growth factor 1 (IGF-1), interleukin 6 (IL-6) and vascular endothelial growth factor (VEGF)) as well as local skeletal muscle gene expression (IGF-1Ea and MGF mRNA) to LLRT with BFR. LLRT with BFR increased (P < 0.05) all measurements of muscle strength by 13 30% in both young and older people. PObf was also increased (P < 0.05) following 4 weeks of LLRT with BFR in both population groups. Acute responses to LLRT with BFR identified an increase (P < 0.05) in GH and VEGF in older people. These are similar response to those seen in the young. Finally local gene expression of MGF mRNA was elevated (P < 0.05) 24 hours post LLRT with BFR in both young and older people. Any changes in muscle and blood flow adaptations may be as a result of increased hormones and growth factors at a circulation and local level. Key words: Blood flow restriction, blood flow, muscle strength, growth hormone, IGF-1
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BOEGEHOLD, MATTHEW ALAN. "THE ROLE OF OXYGEN IN ESCAPE OF SKELETAL MUSCLE ARTERIOLES FROM SYMPATHETIC NERVE STIMULATION (MICROCIRCULATION, BLOOD FLOW)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183816.
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In these experiments, we tested the hypothesis that sympathetic escape in skeletal muscle is mediated through a fall in parenchymal cell oxygen levels following blood flow reduction. This hypothesis predicts that if the fall in parenchymal cell PO₂ during stimulation can be minimized, escape should be reduced. To test this prediction, we studied the behavior of superficial arterioles of the cat sartorius muscle during 3 minutes of sympathetic nerve stimulation. The muscle was covered with silicone oil equilibrated with 0%, 5% and 10% oxygen. During stimulation under 0% oxygen, 90% of visible arterioles showed a significant secondary relaxation (escape). The relaxation averaged 55% of the initial constriction. Under 5% oxygen, resting arteriolar diameter was reduced by an average of 12% and escape was significantly reduced throughout the arteriolar network. Under 10% ambient oxygen, there was an additional 5% reduction in resting diameter and a further reduction of escape. Escape was not attenuated when control diameter was reduced to the same degree with arginine vasopressin, suggesting that the effect of oxygen was specific rather than secondary to an increase in vascular tone. The above observations are also consistent with the hypothesis that escape is mediated through a fall in vascular wall PO₂. To evaluate this possibility, periarteriolar and parenchymal tissue PO₂ were measured with oxygen microelectrodes during sympathetic stimulation under 0% and 10% oxygen suffusion of the muscle. In the proximal arterioles, the periarteriolar PO₂ during control and during stimulation was identical under 0% and 10% oxygen yet escape was reduced by 75% under 10% oxygen. Similarly, escape was reduced 90% in the distal arterioles under 10% oxygen but periarteriolar PO₂ was very nearly the same as that measured under 0% oxygen. In contrast, mean parenchymal tissue PO₂ fell to low levels during stimulation under 0% oxygen but did not fall below normal levels during stimulation under 10% oxygen. These findings argue against the hypothesis that a fall in vascular wall PO₂ is responsible for escape. The findings are consistent with the hypothesis that sympathetic escape in skeletal muscle is mediated through a fall in parenchymal cell PO₂. (Abstract shortened with permission of author.)
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Sandberg, Margareta. "Acupuncture - effects on muscle blood flow and aspects of treatment in the clinicla context." Doctoral thesis, Linköpings universitet, Rehabiliteringsmedicin, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10456.
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The overall aim of this thesis was to elucidate and investigate psychophysiological aspects and effects of acupuncture and needle stimulation. Within this framework emphasis was directed toward the effects of needle stimulation (acupuncture) on muscle blood flow in the tibialis anterior and trapezius muscles in healthy subjects and patients suffering from chronic muscle pain. This study also included evaluation of a new application of photoplethysmography in noninvasive monitoring of muscle blood flow. The evaluation was based on experiments known to provocate skin or muscle blood flow. The psychological aspects studied comprised the effects of manual acupuncture on pain in fibromyalgia patients and the effects of electro-acupuncture on psychological distress and vasomotor symptoms in postmenopausal women in the clinical context. The results showed that photoplethysmography have potential to noninvasively monitor muscle blood flow and to discriminate between blood flow in skin and muscle, although some considerations still have to be accounted for. It was further shown that muscle blood flow change in response to needle stimulation differed between healthy subjects and patients. Deep needle stimulation in the muscle of healthy subjects consistently increased muscle blood flow more than subcutaneous needle stimulation. In the painful trapezius muscle of FMS patients, however, subcutaneous needling was equal or even more effective in increasing muscle blood flow than deep intramuscular stimulation. Generally, needle stimuli had weak effect on blood flow in the trapezius muscle of the severely affected trapezius myalgia patients, possibly depending on older age and lesser number of patients included in the study. The different patterns of blood flow response to needle stimulation between healthy subjects and patients with chronic muscle pain might be a manifestation of altered somatosensory processing in the patients. The clinical studies showed that best pain relief of acupuncture in FMS patients was achieved in the neck-shoulder region, while the effect on the generalised symptoms was of short duration. Well-being and sleep was found to best predict treatment outcome. The results suggest that acupuncture treatment may be used for the alleviation of neck-shoulder pain, primarily, but it is not an alternative as the sole treatment. Electro-acupuncture, significantly decreased psychological distress and climacteric symptoms in postmenopausal women, but not better than a (near-) placebo control, implying pronounced non-specific effects.Akupunktur ingår som en del i traditionell kinesisk medicin (TCM) och har använts i över 2000 år för att lindra sjukdom och symptom. I Sverige blev akupunktur godkänd som smärtlindringsmetod inom Hälso- och Sjukvården 1984. Sedan nästan 10 år är akupunktur jämställd med övrig behandling i sjukvården vilket innebär, att akupunktur kan användas även för behandling av annat än smärta. Förutsättningen är emellertid, att det finns tillräckligt med vetenskapliga belägg, s.k. evidens, för detta. I de allra flesta fall saknas det idag. För att säkerställa att evidens föreligger krävs omfattande forskning om effekter av akupunktur. Syftet med de olika studierna i avhandlingen var att belysa och studera psykologiska och fysiologiska aspekter och effekter av akupunktur och nålstimulering. Effekt på blodflöde i hud och muskel undersöktes på friska personer och på patienter med kronisk muskelsmärta. Normalt krävs ett mindre kirurgiskt ingrepp för att mäta blodflöde i muskel, men i dessa studier användes en mätmetod, som enkelt och utan ingrepp (icke-invasivt) i normala fall används för att mäta blodflöde i huden, s.k. fotopletysmografi (PPG, eng.). Med hjälp av ny teknik användes PPG i dessa studier för att mäta även muskelblodflöde. En studie för utvärdering av den nya PPG-tekniken ingick också i avhandlingen. Utvärderingen av mätmetoden visade goda möjligheter att mäta muskelblodflöde icke-invasivt med hjälp av PPG. Hos friska personer blev effekten på blodflödet störst vid djup stimulering i muskeln och där den s.k. DeQi-känslan framkallades (som vid klassisk akupunktur). Hos patienter med fibromyalgi var nålstimulering i huden lika, eller t.o.m. mer, effektiv att öka muskelblodflödet i skuldran än den djupa nålstimuleringen. De olika mönstren av blodflödesökning mellan de friska personerna och patienterna kan bero på ett förändrat reaktionssätt i nervsystemet som svar på smärtsam stimulering. I två kliniska studier studerades den smärtlindrande effekten av manuell akupunktur vid fibromyalgi och effekten av elektroakupunktur på stress och klimakteriebesvär hos kvinnor i övergångsåldern. Akupunktur vid fibromyalgi visade sig ha bäst smärtlindrande effekt i nack-skulderområdet, medan effekten på de generella symptomen var kortvarig. Patienter som mådde och sov relativt bra erhöll bäst effekt. Efter en behandlingsserie, bestående av elektroakupunktur, minskade stress och klimakteriebesvär påtagligt hos kvinnorna i övergångsåldern, men inte mer än hos en grupp kvinnor, som fick en kontrollbehandling bestående av mycket ytligt placerade nålar i huden. Detta tyder på att en betydlig del av behandlingsresultatet utgjordes av ospecifika effekter eller, s.k. eller placeboeffekter.
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Scriba, E. W. (Ernst Wolfgang). "Proximal feed artery regulation of skeletal muscle blood flow during exercise : the paraplegic model." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/49783.
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Assignment (MPhil)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: The mechanisms of blood flow (BF) control to skeletal muscle during dynamic exercise are still not clearly understood. The paraplegic subject (P) has reduced sympathetic innervation to the lower limbs. The current study was designed to focus on the contribution of neural control, specifically the sympathetic nervous system (SNS), as part of the central vascular mechanism to skeletal muscle BF during dynamic exercise. Aims: We studied BF parameters in P vs. able-bodied subjects (AB) to determine whether the paraplegic can serve as a model for assessing the contribution of the SNS to changes in active vs. inactive muscle BF during exercise. Further questions addressed include: the influence of level of fitness on resting and exercise BF, how lesion level affects BF control in the paraplegic, the 'muscle pump' theory and its hypothesized role in exercise hyperemia and whether blood pooling occurs in the legs of paraplegics. Method: Noninvasive duplex Doppler studies of the large conduit arteries (brachial and common femoral) were performed on 10 elite paraplegic athletes (EP), 10 sedentary paraplegics (SP) en 10 sedentary able-bodied subjects (AB). The paraplegic groups were further subdivided by lesion level with T6 being the critical level. Tests were carried out at rest and after 2 bouts of arm ergometer exercise: a maximal incremental test and 3 minutes at 75% of maximal. Diameter, mean velocity, pulsatile index and blood flow were measured/calculated. Results: Resting heart rate was significantly higher in the paraplegic groups (EP = 80 bpm ± 10, SP = 83 bpm ± 12) vs. the AB group (69 bpm ± 7), p < 0.05. Resting diameter in the common femoral artery (CFA) was similar in EP (5.93 mm ± 1.54) and SP (6.52 mm ± 0.95), but significantly lower than in AB (7.87 mm ± 1.38), p < 0.05. Similar resting pulsatile index (PI) in the CFA were contrary to that previously reported, casting doubt on venous blood pooling theories. Post-exercise values need to be interpreted with caution in view of the large resting differences in CFA diameter. Percentage change values are therefore more appropriate. These differences were not statistically significant, but may suggest interesting trends. Large variability existed for most resting and post-exercise values. Conclusion: The paraplegic subject is an ideal model for the study of the influence of the SNS on blood supply to exercising skeletal muscle. The difference in CFA diameter at rest in the paraplegic vs. the AB group confirms previous results and is probably due to structural/non-physiological changes. Our observation that the BA and CFA diameters in EP and SP subjects do not differ significantly at rest, suggests that training does not have a spillover vasomotor effect on lower limb conduit arteries in paraplegia. Similar BF and PI values post-exercise in the SP and AB groups challenge the muscle pump theory. The SNS has an important role in the control of skeletal muscle blood flow - both at rest (vascular tone) and during exercise (redistribution). Suggestions for future research are made.
AFRIKAANSE OPSOMMING: Die meganismes betrokke by die beheer van bloedvloei (BV) gedurende dinamiese oefening is nog onduidelik. Die parapleeg (P) het verminderde simpatiese innervasie na die onderste ledemate. Die huidige studie fokus op die bydrae van die simpatiese senuwee sisteem (SSS), as deel van die sentrale vaskulêre meganisme, tot skeletale spier BV tydens dinamiese oefening. Doelstellings: Ons het BV parameters in P vs. nie-gestremde proefpersone (kontrole) bestudeer om vas te stelof die parapleeg as model gebruik kan word om die bydrae van die SSS tot veranderings in die BV in aktiewe- en onaktiewe spiere gedurende oefening, te ondersoek. Verdere aspekte wat ondersoek is, sluit in: die invloed van tiksheidvlak ten opsigte van rustende en oefenings BV, of die verlammingsvlak by die parapleeg BV kontrole beïnvloed, die 'spierpomp-teorie' en sy hipotetiese rol in oefeninghiperremie, asook die vraag of bloedsaamstorting in die bene van parapleë plaasvind. Metode: Nie-indringende duplex Doppler studies van die groot geleidingsarteries (bragiaal [BA] en gemene femoral [CFA]) is by 10 elite paraplegiese atlete (EP), 10 sedentêre parapleë (SP) en 10 sedentêre nie-gestremde proefpersone (AB) uitgevoer. Die paraplegiese proefpersone is verder onderverdeel deur die vlak van T6 as kritiese verlammingsvlak te gebruik. Toetse is tydens rus en na 2 arm-ergometer oefeningsessies uitgevoer: een maksimale inkrementeie toets en een van 75% van maksimum intensiteit. Deursnit, gemiddelde vloeispoed, pulsatiewe indeks en bloedvloei is gemeet en/of bereken. Resultate: Rustende hartspoed was beduidend hoër in die paraplegiese groepe (EP = 80 slaelminuut ± 10 en SP = 83 slm ± 12) vs. die AB groep (69 slm ± 7), p < 0.05. Rustende deursnit in die gemene femorale arterie (CFA) was dieselfde in EP (5.93 mm ± 1.54) en SP (6.52 mm ± 0.95), maar beduidend laer as in AB (7.87 mm ± 1.38), p < 0.05. Die feit dat rustende pulsatiewe indeks (PI) in die CFA dieselfde in albei groepe was, laat twyfelontstaan oor die veneuse bloedopdammings teorieë soos weergegee in die literatuur. Na-oefeningswaardes moet omsigtig evalueer word met inagneming van die groot rustende verskille in CFA deursnit. Persentasieverskilwaardes is dus meer toepaslik. Hierdie veskille was nie statisties beduidend nie, maar suggereer interessante tendense. Groot variasie het voorgekom vir beide rustende en na-oefenings waardes. Gevolgtrekking: Die parapleeg is 'n ideale model vir studies om die invloed van die SSS op bloedvloei aan aktiewe skeletale spier te bestudeer. Die verskil in rustende CFA deursnit in die parapleeg vs. die AB groep bevestig vorige resultate en is waarskynlik te wyte aan strukturele, nie-funksionele veranderinge. Ons bevindinge dat die BA en CFA deursneë nie beduidend verskil in die SP en EP groep gedurende rus nie, dui daarop dat gereëlde oefening nie 'n oorloop vasomotor effek op die onderste ledemate in die parapleeg het nie. Die feit dat daar geen verskil aangetoon kon word tussen BV en PI waardes na-oefening in die SP en AB groepe, betwis die spierpomp teorie. Die studie toon dat die SSS 'n belangrike rol in die beheer van skeletale spier bloedvloei speel - beide met rus (vaskulêre tonus) en gedurende oefening (herdistribusie). Voorstelle vir toekomstige navorsing word gemaak.
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Smith, Joshua R. "The influence of respiratory muscle fatigue on inactive limb blood flow during cycling exercise." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15699.
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Master of ScienceDepartment of Kinesiology
Craig A. Harms
An increased work of breathing during heavy whole body exercise can lead to respiratory muscle fatigue (RMF) and decreased leg blood flow. Heavy exercise also increases inactive limb and cutaneous blood flow. It is not known, however, how RMF affects inactive limb and cutaneous blood flow. Therefore, we tested the hypothesis that RMF during heavy exercise would reduce: 1) inactive limb blood flow, 2) inactive limb vascular conductance, and 3) inactive limb cutaneous blood flow. Twelve healthy men (23 ± 2 yrs) completed baseline pulmonary function tests followed by an incremental cycle test to VO[subscript]2[subscript]max. Subjects then cycled at both 70% and 85%VO2max (randomized) for 20 minutes. Subjects performed a second 85%VO[subscript]2[subscript]max test ingesting N-acetylcysteine (NAC) (1800mg), which has been reported to reduce RMF, 45 minutes prior the test. Maximum inspiratory pressures (P[subscript]Imax) were measured prior to and immediately following each exercise trial to determine RMF. During exercise, brachial artery blood flow (BABF) was measured via Doppler ultrasound and arm cutaneous blood flow was assessed by laser-Doppler flowmetry. Cutaneous vascular conductance (CVC) was calculated as flux/mean arterial pressure and scaled as % maximal CVC (sites heated to 46[degrees]C). Mean arterial pressure (MAP) was measured manually. Significant RMF occurred with 85%VO[subscript]2[subscript]max (12.8 ± 9.8%), but not with 70%VO[subscript]2[subscript]max (p>0.05). BABF significantly increased from baseline to end exercise in both conditions and was significantly lower (~18%) following the 85%VO[subscript]2[subscript]max test. The amount of RMF at 85%VO[subscript]2[subscript]max was inversely related to the change in BABF (r= -0.66, p<0.05). BA vascular conductance was significantly higher at end exercise at 70%VO[subscript]2[subscript]max compared to 85%VO[subscript]2[subscript]max (2.60 ± 0.73 vs. 2.00 ± 0.42 mLmin[superscript]-1mmHg[superscript]-1, resp.). The amount of RMF at 85%VO[subscript]2[subscript]max was inversely related to BA vascular conductance at end exercise (r= -0.80, p<0.05). Cutaneous vascular conductance was not different (p>0.05) between trials. With NAC, RMF was reduced and BABF was consequently significantly higher (~30%) compared to 85%VO[subscript]2[subscript]max. These data suggest that RMF during heavy whole body exercise decreases inactive arm blood flow and vascular conductance, but not cutaneous blood flow.
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Craig, Jesse Charles. "Effect of beetroot supplementation on conduit artery blood flow and muscle oxygenation during handgrip exercise." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/19093.
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Master of ScienceDepartment of Kinesiology
Thomas J. Barstow
Dietary nitrate supplementation via beetroot juice (BR) has been shown to have positive effects on mitochondrial and muscle efficiency during large muscle mass exercise in humans, and more recently on locomotory muscle blood flow [Q-dot] in rats. To date, an integrated measure of these effects has not been performed in humans. Therefore, we assessed the influence of BR on [Q-dot] and muscle oxygenation characteristics during moderate and severe intensity handgrip exercise. Seven healthy men (age: 25 ± 3 yrs; height: 179 ± 4 cm; weight: 82 ± 9 kg) completed four constant-power exercise tests randomly assigned to condition (BR or placebo (PL)) and intensity (moderate (40% peak) or severe (85% peak)). Resting mean arterial pressure was significantly lower after BR compared to PL (79.3 ± 5.8 vs 86.8 ± 6.7 mmHg; p < 0.01). All subjects were able to sustain 10 min of exercise at moderate intensity in both conditions. BR had no significant effect on exercise tolerance during severe (342 ± 83 vs 382 ± 138 s, p = 0.382). Brachial artery [Q-dot] was not significantly different after BR at rest or any time during exercise in either intensity. Deoxygenated-[hemoglobin + myoglobin] was elevated at min 2 & 3 for moderate (p < 0.05) and throughout severe exercise (p = 0.03) after BR. The estimated metabolic cost ([V-dot]O₂) was not significantly different during either intensity after BR. These findings support the notion that an acute dose of BR may be valuable to reduce blood pressure in young adults, but revealed that it does not augment [Q-dot] or [V-dot]O₂ during small muscle mass handgrip exercise.
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Pitcher, Julia Blanche. "Influence of muscle blood flow on fatigue during intermittent human hand-grip exercise and recovery /." Adelaide, 1995. http://web4.library.adelaide.edu.au/theses/09SB/09sbp6823.pdf.
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Herspring, Kyle F. "Effects of antioxidants on contracting spinotrapezius muscle microvascular oxygenation and blood flow in aged rats." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/700.
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Jöbsis, Paul D. "Muscle oxygenation and blood flow during submersion in ducks (anas platyrhynchos) and seals (phoca vitulina) /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907822.
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Behnke, Bradley J., Michael W. Ramsey, John N. Stabley, James M. Dominguez, Robert T. Davis, Danielle J. McCullough, Judy M. Muller-Delp, and Michael D. Delp. "Effects of Aging and Exercise Training on Skeletal Muscle Blood Flow and Resistance Artery Morphology." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/4125.
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With old age, blood flow to the high-oxidative red skeletal muscle is reduced and blood flow to the low-oxidative white muscle is elevated during exercise. Changes in the number of feed arteries perforating the muscle are thought to contribute to this altered hyperemic response during exercise. We tested the hypothesis that exercise training would ameliorate age-related differences in blood flow during exercise and feed artery structure in skeletal muscle. Young (6–7 mo old, n = 36) and old (24 mo old, n = 25) male Fischer 344 rats were divided into young sedentary (Sed), old Sed, young exercise-trained (ET), and old ET groups, where training consisted of 10–12 wk of treadmill exercise. In Sed and ET rats, blood flow to the red and white portions of the gastrocnemius muscle (GastRed and GastWhite) and the number and luminal cross-sectional area (CSA) of all feed arteries perforating the muscle were measured at rest and during exercise. In the old ET group, blood flow was greater to GastRed (264 ± 13 and 195 ± 9 ml·min−1·100 g−1 in old ET and old Sed, respectively) and lower to GastWhite (78 ± 5 and 120 ± 6 ml·min−1·100 g−1 in old ET and old Sed, respectively) than in the old Sed group. There was no difference in the number of feed arteries between the old ET and old Sed group, although the CSA of feed arteries from old ET rats was larger. In young ET rats, there was an increase in the number of feed arteries perforating the muscle. Exercise training mitigated old age-associated differences in blood flow during exercise within gastrocnemius muscle. However, training-induced adaptations in resistance artery morphology differed between young (increase in feed artery number) and old (increase in artery CSA) animals. The altered blood flow pattern induced by exercise training with old age would improve the local matching of O2 delivery to consumption within the skeletal muscle.
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Goodwin, Matthew Lawrence Gladden L. Bruce. "VO2 on-kinetics in isolated canine muscle in situ during slowed convective O2 delivery." Auburn, Ala, 2008. http://hdl.handle.net/10415/1464.
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Ferguson, Scott Kohman. "Impact of dietary nitrate supplementation via beetroot juice on exercising muscle vascular control in rats." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/15048.
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Master of ScienceDepartment of Kinesiology
David C. Poole
Introduction: Dietary nitrate(NO[subscript]3[superscript]-) supplementation, via its reduction to nitrite (NO [subscript] 2 [superscript]-) and subsequent conversion to nitric oxide (NO) and other reactive nitrogen intermediates, reduces blood pressure and the O[subscript]2 cost of submaximal exercise in humans. Despite these observations, the effects of dietary NO [subscript]3 [superscript]- supplementation on skeletal muscle vascular control during locomotory exercise remain unknown. We tested the hypotheses that dietary NO [subscript]3 [superscript]- supplementation via beetroot juice (BR) would reduce mean arterial pressure (MAP) and increase hindlimb muscle blood flow in the exercising rat. Methods: Male Sprague-Dawley rats (3-6 months) were administered either NO [subscript]3 [superscript]- (via beetroot juice; 1 mmol · kg[superscript]-[superscript]1 · day[superscript]-[superscript]1, BR n=8) or untreated (control, n=11) tap water for 5 days. MAP and hindlimb skeletal muscle blood flow and vascular conductance (radiolabeled microsphere infusions) were measured during submaximal treadmill running (20 m · min[superscript]-[superscript]1, 5% grade). Results: BR resulted in significantly lower exercising MAP (control: 137 ± 3, BR: 127 ± 4 mmHg, P<0.05) and blood [lactate] (control: 2.6 ± 0.3, BR: 1.9 ± 0.2 mM, P<0.05) compared to control. Total exercising hindlimb skeletal muscle blood flow (control: 108 ± 8, BR: 150 ± 11 ml · min[superscript]-[superscript]1 · 100 g[superscript]-[superscript]1, P<0.05) and vascular conductance (control: 0.78 ± 0.05, BR: 1.16 ± 0.10 ml · min[superscript]-[superscript]1 · 100 g[superscript]-[superscript]1 · mmHg[superscript]-[superscript]1, P<0.05) were greater in rats that received beetroot juice compared to control. The relative differences in blood flow and vascular conductance for the 28 individual hindlimb muscles and muscle parts correlated positively with their percent type IIb + d/x muscle fibers (blood flow: r=0.74, vascular conductance: r=0.71, P<0.01 for both). Conclusion: These data support the hypothesis that NO [subscript]3 [superscript]- supplementation improves vascular control and elevates skeletal muscle O [subscript]2 delivery during exercise predominantly in fast-twitch type II muscles, and provide a potential mechanism by which NO [subscript]3 [superscript]- supplementation improves metabolic control.
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Dodd, Laurie Rose. "Arteriolar network responses to opposing dilator and constrictor stimuli: Mechanism of sympathetic attenuation during muscle contraction." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184572.
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Evidence suggests different sections of the arteriolar network supplying muscle can respond independently and this may provide a mechanism for the localized distribution of blood flow. This hypothesis was tested in the microcirculation of the cat sartorius muscle by measurement of arteriolar diameter changes during muscle contraction and sympathetic nerve stimulation in each consecutive section of the network. The diameter changes were referenced to the initial distribution of resistance across the network, as determined from arteriolar pressure measurements and morphometric data. This led to an estimate of the change in network resistance. Unlike previous reports, the most distal arterioles dilated little during muscle contraction and our resistance estimate indicates these vessels play an insignificant role in functional hyperemia. The more proximal, third order arterioles dilated proportionately more than other arteriolar orders and made the largest single contribution to resting resistance. Similarly, these vessels were the largest single site of resistance change during sympathetic stimulation. Together, these findings suggest the third order arterioles play a dominant role in regulating flow to the capillaries that each supplies. Antagonism of sympathetic control during muscle contraction has been attributed to direct inhibition of vascular smooth muscle contraction and to inhibition of sympathetic neurotransmission. Evidence to support the latter mechanism comes from the observation that functional dilation is reduced with exogenous norepinephrine as compared to sympathetic stimulation. However, exogenous norepinephrine may bind to both alpha-1 and alpha-2 adrenergic receptors, whereas that released by sympathetic stimulation may bind primarily to alpha-1 receptors. Since this difference could be significant, functional dilation after systemic injection of norepinephrine or phenylephrine, a selective alpha-1 agonist, was compared to that during sympathetic stimulation. In contrast to the findings with norepinephrine, functional dilation after phenylephrine did not differ from that observed during sympathetic stimulation. This indicates the dilator substance(s) released during exercise may selectively inhibit alpha-1 mediated vasoconstriction but less effectively inhibit vasoconstriction mediated by alpha-2 receptors. Furthermore, these findings suggest that the vasodilator mechanism may act primarily at the level of the vascular smooth muscle, without appreciable pre-junctional inhibition of sympathetic nerves.
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Ping, Peipei. "Autoregulation of blood flow during sympathetic nerve stimulation in the arteriolar network on cat sartorius muscle." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185318.
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Autoregulation is the tendency for blood flow to remain constant despite a change in arterial perfusion pressure. Flow regulation is achieved by adjustment of arteriolar caliber to the pressure change. The responses of arterioles are most commonly explained by either the metabolic or myogenic hypothesis. According to the metabolic hypothesis, the initial decrease in blood flow that accompanies a reduction in arterial pressure would reduce oxygen delivery and decrease tissue oxygen tension. We reasoned that the contribution of this mechanism to autoregulation of flow would be increased during sympathetic nerve stimulation because the latter causes arteriolar constriction and decreases tissue oxygen tension. However, the elevated vascular tone might also influence the myogenic response (i.e., arteriolar constriction to elevated intravascular pressure). In these experiments, we examined flow and diameter changes in arterioles of the exteriorized cat sartorius muscle during sympathetic nerve stimulation and tested the contribution of both metabolic and myogenic factors. Without sympathetic nerve stimulation, autoregulation was weak, flow fell coincident with reduced perfusion pressure. Sympathetic nerve stimulation caused significant constriction of arterioles, enhancing autoregulation, and increasing flow about 20% to 60% during perfusion pressure reduction from 110 to 80, 60, and 40 mmHg. With sympathetic nerve stimulation, arteriolar dilation to arterial pressure reduction was enhanced. This enhanced dilation was not abolished by 20% oxygen in a suffusate over the muscle, suggesting that it was not due to an enhanced metabolic response. On the other hand, arteriolar constriction to venous pressure elevation (which raises arteriolar intravascular pressure), was increased during sympathetic nerve stimulation, indicating an enhanced myogenic response. Arteriolar dilation to pressure reduction was also enhanced during norepinephrine infusion, showing that prejunctional inhibition of neurotransmitter release was not involved. Vasopressin and BayK8644 had similar effects, indicating the enhanced myogenic response did not require adrenergic or receptor mediated vasoconstriction. The autoregulatory response was also examined for all the orders of arterioles in the network. Third and fourth order arterioles showed significantly more dilation during pressure reduction under both with and without sympathetic nerve stimulation. With sympathetic nerve stimulation, arteriolar dilation during pressure reduction was significantly enhanced in first through fourth order arterioles and also appeared to be enhanced in fifth and sixth orders. Enhanced autoregulation appears due to generalized increase in dilation in all orders.
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Gurley, Katelyn. "USE OF HYBRID DIFFUSE OPTICAL SPECTROSCOPIES IN CONTINUOUS MONITORING OF BLOOD FLOW, BLOOD OXYGENATION, AND OXYGEN CONSUMPTION RATE IN EXERCISING SKELETAL MUSCLE." UKnowledge, 2012. http://uknowledge.uky.edu/cbme_etds/3.
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This study combines noninvasive hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] with occlusive calibration for continuous measurement of absolute blood flow (BF), tissue blood oxygenation (StO2), and oxygen consumption rate (VO2) in exercising skeletal muscle. Subjects performed rhythmic dynamic handgrip exercise, while an optical probe connected to a hybrid NIRS/DCS flow-oximeter directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and [tHb]), StO2, relative BF (rBF), and relative VO2 (rVO2) in the forearm flexor muscles. Absolute baseline BF and VO2 were obtained through venous and arterial occlusions, respectively, and used to calibrate continuous relative parameters. Previously known problems with muscle fiber motion artifact in optical measurements were mitigated with a novel dynamometer-based gating algorithm. Nine healthy young subjects were measured and results validated against previous literature findings. Ten older subjects with fibromyalgia and thirteen age-matched healthy controls were then successfully measured to observe differences in hemodynamic and metabolic response to exercise. This study demonstrates a novel application of NIRS/DCS technology to simultaneously evaluate quantitative hemodynamic and metabolic parameters in exercising skeletal muscle. This method has broad application to research and clinical assessment of disease (e.g. peripheral vascular disease, fibromyalgia), treatment evaluation, and sports medicine.
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Pearson, James. "Haemodynamic responses to heat stress and hypohydration in resting and exercising humans : implications for the regulation of skeletal muscle blood flow." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4344.
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Heat stress-induced hyperthermia and exercise-induced hypohydration are associated with marked alterations in limb and systemic haemodynamics in humans. However, the mechanisms underlying these alterations their effects on muscle blood flow are not well understood. The present thesis examined whether whole body and local heat stresses increased limb skin and muscle blood flow (Study 1) and whether hypohydration and hyperthermia compromised leg muscle, skin and systemic haemodynamics (Study 2). The effects of heat stress and combined hypohydration and hyperthermia were examined at rest and during mild small muscle mass exercise in humans. The results from Study 1 suggested that heat stress was accompanied by vasodilation in both skeletal muscle and skin vasculatures. Therefore in line with concomitant elevations in blood flow, skeletal muscle and skin vasodilation contribute to increases in leg blood flow and vascular conductance with whole body heat stress. Furthermore, increases in leg muscle and skin blood flow with isolated elevations in leg tissue temperature accounted for at least one half of the total increase in leg blood flow with whole body heat stress. Enhanced leg blood flow owed to a net vasodilation as explained by an elevation in vasodilator activity that exceeded increases in vasoconstrictor activity. This phenomenon was closely related to increases in muscle temperature and intravascular adenosine triphosphate (ATP). The results from Study 2 demonstrated that mild and moderate hypohydration and hyperthermia do not compromise leg muscle and skin blood flow or cardiac output at rest or during mild exercise in humans. Furthermore, acute rehydration did not alter leg muscle and skin blood flow or cardiac output compared to hypohydration and hyperthermia despite large alterations in blood volume and haematological variables and the restoration of core temperature. Taken together, the findings of this thesis indicate that: 1) heat stress induces vasodilation in both skeletal muscle and cutaneous vasculature, 2) elevations in muscle temperature and intravascular ATP play a role in heat stress- and exercise-induced hyperaemia, and 3) moderate hypohydrationinduced hypovolemia and haemoconcentration and rehydration-induced hypervolaemia and haemodilution do not alter leg blood flow or cardiac output at rest and during low intensity exercise in humans when a large cardiovascular reserve is available.
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Ferguson, Scott Kohman. "Skeletal muscle vascular and metabolic control: impacts of exogenous vs. endogenous nitric oxide synthesis." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/19774.
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Doctor of PhilosophyDepartment of Anatomy and Physiology
David C. Poole
The purpose of this dissertation is to expand our knowledge on the physiological effects of the ubiquitous signaling molecule nitric oxide (NO). Focus is given to the impacts of the nitrate (NO[subscript]3[superscript]-) nitrite (NO[subscript]2[superscript]-) NO pathway on skeletal muscle vascular and metabolic function during exercise. The NO[subscript]3[superscript]--NO[subscript]2[superscript]--NO pathway has garnered tremendous research interest due to its ability to upregulate NO bioavailability independently of NO synthase (NOS) function and thus impact the metabolic responses to exercise. Chapter 2 demonstrates that NO[subscript]3[superscript]- supplementation via beetroot juice (BR) augments the skeletal muscle vascular responses to exercise. Five days of BR supplementation resulted in a significantly higher skeletal muscle blood flow (BF) and vascular conductance (VC) during exercise when compared to control. The increases in BF and VC were preferentially directed to muscles and muscle portions comprised predominantly of fast twitch fibers. Furthermore, exercising blood [lactate] was reduced, suggesting improved metabolic control. In chapter 3, BR resulted in a slower fall in the microvascular PO[subscript]2 (PO[subscript]2[subscript]m[subscript]v, the soul driving force for blood myocyte O[subscript]2 flux) during the crucial rest-contraction transition thereby preserving the pressure head needed to move O[subscript]2 from the capillary into the myocyte. Chapter 4 examines the effects of BR on fast vs. slow twitch muscles in which BR raised the PO[subscript]2[subscript]m[subscript]v during the steady state of muscle contractions in fast but not slow twitch muscles, likely due to the lower PO[subscript]2[subscript]m[subscript]v at rest and throughout muscle contractions within these tissues. Chapter 5 investigates the effects of direct arterial NO[subscript]2[superscript]- infusion on skeletal muscle BF and VC during exercise in rats with NOS blockade via N[superscript]G-nitro-L arginine methyl ester. NO[subscript]2[superscript]- infusion restored MAP and VC to levels observed in healthy control animals (with intact NOS function) highlighting the potential for a NO[subscript]2[superscript]- based therapy to positively impact vascular function in those with compromised NOS function such that is evident in many prevalent diseases. These results provide crucial mechanistic insight into the improved exercise tolerance observed in humans following NO[subscript]3[superscript]- supplementation whilst also challenging our current understanding of NO’s role in physiology and pathophysiology.
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Holdsworth, Clark T. "Effects of dietary fish oil on skeletal muscle vascular control in chronic heart failure rats: rest and exercise." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15814.
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Master of ScienceDepartment of Kinesiology
Timothy I. Musch
Impaired vasomotor control in chronic heart failure (CHF) limits the delivery of O[subscript]2 to skeletal muscle during exercise. Previous results demonstrate significant increases in skeletal muscle blood flow (BF) during exercise with omega-3 polyunsaturated fatty acid (PUFA) supplementation via fish oil (FO) versus safflower oil (SO) in healthy rats (Stebbins CL et al., Int J Sport Nutr Exerc Metab 20:475-86, 2010). Whether PUFA supplementation with FO will improve vasomotor control in CHF and skeletal muscle BF during exercise remains to be determined. This investigation tested the hypothesis that PUFA supplementation with FO would augment the skeletal muscle BF response to exercise in rats with CHF when compared to SO. CHF was induced in male Sprague-Dawley rats by myocardial infarction produced via left coronary artery ligation. Rats were then randomized to dietary FO (20% docosahexaenoic acid and 30% eicosapentaenoic acid, n = 8) or SO (5% safflower, n = 6) supplementation for 6 weeks. Rats remained on their respective diets until final experiments were conducted. Following acute instrumentation and recovery (> 1 hour), mean arterial pressure (MAP), skeletal muscle BF to the total hindlimb and individual muscles (via radiolabeled microspheres), and blood lactate concentration were determined during rest, submaximal treadmill exercise and exercise+LNAME (20 m · min[superscript]-[superscript]1, 5% incline). Left ventricular end-diastolic pressure (LVEDP) measured in the SO and FO groups during instrumentation were similar and demonstrated moderate CHF (LVEDP; SO: 14 ± 2; FO: 11 ± 1 mmHg, P>0.05). During submaximal exercise, MAP (SO: 128 ± 3; FO: 132 ± 3 mmHg) and blood lactate (SO: 3.8 ± 0.4; FO: 4.6 ± 0.5 mmol · l[superscript]-[superscript]1) were similar (P>0.05) between groups. Exercising hindlimb skeletal muscle BF was higher in SO compared to FO (SO: 120 ± 11; FO: 93 ± 4 ml · min[superscript]-[superscript]1 · 100 g[superscript]-[superscript]1). Specifically, 17 of 28 individual hindlimb muscle BF’s were higher (P<0.05) in SO. These data suggest that PUFA supplementation with FO in rats with moderate CHF decreases the skeletal muscle BF response to submaximal whole body exercise.
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Ahmadi, Sirous. "Monitoring muscle oxygenation and myoelectric activity after damage-inducing exercise." Thesis, The University of Sydney, 2007. http://hdl.handle.net/2123/2240.
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In this thesis, three experiments were conducted to monitor: (i) muscle oxygenation and electromyographic activity of the biceps brachii after exercise-induced muscle damage (ii) muscle oxygenation after downhill walking-induced muscle damage, and, (iii) muscle oxygenation following a bout of vigorous concentric exercise. Maximal eccentric exercise (EE) of biceps brachii resulted in significantly increased mean resting oxygen saturation and decreased deoxyhaemoglobin. During isometric contractions at 50% and 80% of subjects’ maximum voluntary torque (MVT), oxygen desaturation and resaturation kinetics and volume were significantly decreased after EE, and these declines were significantly prevalent over the following 6 days. Additionally, a significant shift in median frequency intercept (measured by electromyography; EMG) towards lower frequencies was observed during isometric contractions at both 50% and 80% MVT after EE in the exercised arm. After an exhaustive session of downhill walking, another form of EE, resting total haemoglobin and oxyhaemoglobin decreased. Furthermore, during isometric contractions at 30%, 50% and 80% of MVT, prolonged and significant increases were observed in oxygen desaturation and resaturation kinetics and volumes after ambulatory EE. In contrast to the two EE experiments, concentric contractions did not evoke any prolonged changes in muscle oxygenation. Collectively, the findings of this thesis revealed significant and prolonged changes in muscle oxygenation at rest and during exercise, following sessions of strenuous eccentric exercise. Although not clear, the possible mechanism responsible for the changes in muscle oxygenation after EE could be increased resting muscle oxygen utilization due to probable muscle damage and a subsequent requirement of energy demanding repair processes. Concentric exercise resulted in fatigue, but it did not affect muscle oxygenation. Although a prolonged reduction in EMG median frequency intercept was observed after EE, this was not closely time-associated with the biochemical, anthropometric or functional markers of muscle damage.
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Ahmadi, Sirous. "Monitoring muscle oxygenation and myoelectric activity after damage-inducing exercise." University of Sydney, 2007. http://hdl.handle.net/2123/2240.
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Doctor of PhilosophyIn this thesis, three experiments were conducted to monitor: (i) muscle oxygenation and electromyographic activity of the biceps brachii after exercise-induced muscle damage (ii) muscle oxygenation after downhill walking-induced muscle damage, and, (iii) muscle oxygenation following a bout of vigorous concentric exercise. Maximal eccentric exercise (EE) of biceps brachii resulted in significantly increased mean resting oxygen saturation and decreased deoxyhaemoglobin. During isometric contractions at 50% and 80% of subjects’ maximum voluntary torque (MVT), oxygen desaturation and resaturation kinetics and volume were significantly decreased after EE, and these declines were significantly prevalent over the following 6 days. Additionally, a significant shift in median frequency intercept (measured by electromyography; EMG) towards lower frequencies was observed during isometric contractions at both 50% and 80% MVT after EE in the exercised arm. After an exhaustive session of downhill walking, another form of EE, resting total haemoglobin and oxyhaemoglobin decreased. Furthermore, during isometric contractions at 30%, 50% and 80% of MVT, prolonged and significant increases were observed in oxygen desaturation and resaturation kinetics and volumes after ambulatory EE. In contrast to the two EE experiments, concentric contractions did not evoke any prolonged changes in muscle oxygenation. Collectively, the findings of this thesis revealed significant and prolonged changes in muscle oxygenation at rest and during exercise, following sessions of strenuous eccentric exercise. Although not clear, the possible mechanism responsible for the changes in muscle oxygenation after EE could be increased resting muscle oxygen utilization due to probable muscle damage and a subsequent requirement of energy demanding repair processes. Concentric exercise resulted in fatigue, but it did not affect muscle oxygenation. Although a prolonged reduction in EMG median frequency intercept was observed after EE, this was not closely time-associated with the biochemical, anthropometric or functional markers of muscle damage.
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Hammel, Lauren E. "Effects of dietary fish oil supplementation on the skeletal muscle blood flow response to submaximal treadmill exercise." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/738.
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Martin, Denis James. "An investigation into the effects of low level laser therapy on arterial blood flow in skeletal muscle." Thesis, University of Ulster, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385613.
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Lauver, Jakob Del. "The Effect of Eccentric Exercise with Blood Flow Restriction on Muscle Damage, Neuromuscular Activation, and Microvascular Oxygenation." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430489158.
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Copp, Steven Wesley. "Enzymatic regulation of skeletal muscle oxygen transport: novel roles for neuronal nitric oxide synthase." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/15512.
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Doctor of PhilosophyDepartment of Anatomy and Physiology
Timothy I. Musch
Nitric oxide (NO) is synthesized via distinct NO synthase (NOS) enzymes and constitutes an essential cardiovascular signaling molecule. Whereas important vasomotor contributions of endothelial NOS (eNOS) have been well-described, the specific vasomotor contributions of nNOS-derived NO in healthy subjects during exercise are unknown. The purpose of this dissertation is to test the global hypothesis that nNOS-derived NO is a critical regulator of exercising skeletal muscle vascular control. Specifically, we utilized the selective nNOS inhibitor S-methyl-L-thiocitrulline (SMTC) to investigate the effects of nNOS-derived NO on skeletal muscle vascular function within established rodent models of exercise performance. The first investigation (Chapter 2) identifies that nNOS inhibition with SMTC increases mean arterial pressure (MAP) and reduces rat hindlimb skeletal muscle blood flow at rest whereas there are no effects during low-speed (20 m/min) treadmill running. In Chapter 3 it is reported that nNOS inhibition with SMTC reduces blood flow during high-speed treadmill running (>50 m/min) with the greatest relative effects found in highly glycolytic fast-twitch muscles and muscle parts. Chapter 4 demonstrates that nNOS-derived NO modulates contracting skeletal muscle blood flow (increases), O2 consumption (VO2, increases), and force production (decreases) in the rat spinotrapezius muscle and thus impacts the microvascular O2 delivery-VO2 ratio (which sets the microvascular partial pressure of O2, PO2mv, and represents the pressure head that drives capillary-myocyte O2 diffusion). In Chapter 5 we report that systemic administration of the selective nNOS inhibitor SMTC does not impact lumbar sympathetic nerve discharge. This reveals that the SMTC-induced peripheral vascular effects described herein reflect peripheral nNOS-derived NO signaling as opposed to centrally-derived regulation. In conclusion, nNOS-derived NO exerts exercise-intensity and muscle fiber-type selective peripheral vascular effects during whole-body locomotor exercise. In addition, nNOS-derived NO modulates skeletal muscle contractile and metabolic function and, therefore, impacts the skeletal muscle PO2mv. These data identify novel integrated roles for nNOS-derived NO within healthy skeletal muscle and have important implications for populations associated with reduced NO bioavailability and/or impaired nNOS structure and/or function specifically (e.g., muscular dystrophy, chronic heart failure, advanced age, etc.).
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Hammer, Shane Michael. "Perfusive and diffusive oxygen transport in skeletal muscle during incremental handgrip exercise." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/36202.
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Master of ScienceDepartment of Kinesiology
Thomas J. Barstow
Limb blood flow increases linearly with exercise intensity; however, invasive measurements of microvascular muscle blood flow during incremental exercise have demonstrated submaximal plateaus. Diffuse correlation spectroscopy (DCS) noninvasively quantifies relative changes in microvascular blood flow at rest via a blood flow index (BFI). The purpose of this study was to quantify relative changes in tissue blood flow during exercise using DCS, compare the BFI of the flexor digitorum superficialis (BFI[subscript]FDS) muscle to brachial artery blood flow (Q̇[subscript]BA) measured via Doppler ultrasound, and employ near infrared spectroscopy (NIRS) alongside DCS to simultaneously measure perfusive and diffusive oxygen transport within a single volume of exercising skeletal muscle tissue. We hypothesized Q̇[subscript]BA would increase with increasing exercise intensity until task failure, BFI[subscript]FDS would plateau at a submaximal work rate, and muscle oxygenation characteristics (total-[heme], deoxy-[heme], and % saturation) measured with NIRS would demonstrate a plateau at a similar work rate as BFI[subscript]FDS. Sixteen subjects (23.3 ± 3.9 yrs; 170.8 ± 1.9 cm; 72.8 ± 3.4 kg) participated in this study. Peak power (P[subscript]peak) was determined for each subject (6.2 ± 1.4W) via an incremental handgrip exercise test to task failure. Measurements of Q̇[subscript]BA, BFI[subscript]FDS, total-[heme], deoxy-[heme], and % saturation were made during each stage of the incremental exercise test. Q̇[subscript]BA increased with exercise intensity until the final work rate transition (p < 0.05). No increases in BFI[subscript]FDS or muscle oxygenation characteristics were observed at exercise intensities greater than 51.5 ± 22.9% of P[subscript]peak and were measured simultaneously in a single volume of exercising skeletal muscle tissue. Differences in muscle recruitment amongst muscles of the whole limb may explain the discrepancies observed in Q̇[subscript]BA and BFI[subscript]FDS responses during incremental exercise and should be further investigated.
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Cortobius, Daniel, and Niklas Westblad. "Optimizing strength training for hypertrophy : A periodization of classic resistance training and blood-flow restriction training." Thesis, Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:gih:diva-4373.
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Aim The main aim of this study was to investigate if a combination of classic resistance training and blood flow restricted resistance exercise (BFRE) training would result in greater increases in quadriceps muscle growth compared with other strength training studies. The second aim was to investigate if there would be any difference in muscle hypertrophy between men and women after the training intervention. Method Twenty untrained subjects (10 males and 10 female) were recruited to participate in a 10-week unilateral resistance training intervention. Sixteen subjects completed the training intervention. After two familiarization sessions subjects performed three sessions per week in leg press and leg extension, except for week 4 and 8 were subjects performed five BFRE training sessions Monday to Friday. All subjects performed a one repetition maximum test in leg press and leg extension pre and post the training intervention. Ultrasound screening was performed pre and post training intervention to measure muscle thickness in m. vastus lateralis (VL). Results The 10-week intervention resulted in a significant increase of VL muscle thickness by 15,1 % ± 7,6 (p ≤ 0,01). Both men and women increased in VL muscle thickness, men (n=7) by 15,4 % ± 9,3 (p ≤ 0,01) and women (n=9) by 14,8 % ± 6,0 (p ≤ 0,01), with no difference between genders. Maximal strength increased for the entire group in the leg press by 59,1 % ± 27,4 (p ≤ 0,01) and in the leg extension by 19,8 % ± 13,1 (p ≤ 0,01). Men had an increase of 58,1 % ± 18,0 (p ≤ 0,01) and women with 60,3 % ± 32,8 (p ≤ 0,01) in the leg press. In the leg extension women and men increased their maximal strength by 23,3 % ± 7,4 (p ≤ 0,01) respectively 17,0 % ± 14,4 (p = 0,051). Conclusions Our unique training protocol resulted in a superior increase in muscle growth in comparison with most other strength training studies. Our result can be converted to an increase of 17,3 % (0,25 % per day) in VL muscle CSA, which is much greater than the mean increase of 0,11 % per day reported in a large meta-analysis (Wernbom, Augustsson & Thomeé 2007).
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Ward, Aaron Tyler. "The Effect of Sequential Lower Body Positive Pressure on Forearm Blood Flow and Muscle Deoxygenation During Dynamic Handgrip Exercise." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1461849449.
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Aaker, Aaron Paul. "Vasomotor responses of rat skeletal muscle arterioles to norepinephrine and adenosine." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3012943.
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Rico, Gabrielle. "Effects of pentoxifylline on exercising skeletal muscle vascular control in rats with chronic heart failure." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15671.
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Master of ScienceDepartment of Kinesiology
Timothy I. Musch
Both cardiac and peripheral vasculature dysfunction likely contribute, in part, to elevations in TNF-[alpha] and exercise intolerance in chronic heart failure (CHF). The pharmaceutical TNF-[alpha] synthesis suppressor pentoxifylline (PTX) reduces plasma [TNF-[alpha]] and improves left ventricular (LV) function in CHF rats, but the effects of PTX on skeletal muscle blood flow (BF) and vascular conductance (VC) during exercise are unknown. We tested the hypothesis that PTX would elevate skeletal muscle BF and VC at rest and during submaximal treadmill exercise in CHF rats (coronary artery ligation). CHF rats received i.p. injections of 30 mg·kg[superscript]-[superscript]1·day[superscript]-[superscript]1 of PTX (CHF+PTX, n=13) or saline (CHF, n=8) for 21 days. Mean arterial pressure (MAP) and BF (radiolabeled microsphere infusions) were measured at rest and during treadmill exercise (20 m/min, 5% grade). Myocardial infarct (MI) size was not different between groups (CHF: 37±4, CHF+PTX: 37±3% of LV wall; p>0.05). Resting and exercising MAP was greater in CHF+PTX compared to CHF (p<0.05 for both). At rest, total hindlimb skeletal muscle BF and VC were not different between groups (p>0.05). However, during exercise PTX increased total hindlimb BF (CHF: 83±9, CHF+PTX: 114±8 ml·min[superscript]-[superscript]1·100g[superscript]-[superscript]1, p<0.05) and VC (CHF: 0.75±0.08, CHF+PTX: 0.88±0.06 ml·min[superscript]-[superscript]1·100g[superscript]-[superscript]1·mmHg[superscript]-[superscript]1, p<0.05). Furthermore, exercising BF was increased in 21, and VC in 11, of the 28 individual hindlimb muscles or muscle parts with no apparent fiber-type specificity. Thus, PTX administration augments skeletal muscle BF and VC during locomotory exercise in CHF rats, which carries important therapeutic implications for CHF patients.
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Pellinger, Thomas Kent. "Impact of postexercise hyperemia on glucose regulation in humans /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2008. http://hdl.handle.net/1794/9018.
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Thesis (Ph. D.)--University of Oregon, 2008.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 151-168). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Nygren, Anders T. "Response of human skeletal muscle to chronic and acute exercise and ischemia : muscle dimensions, tissue water and blood flow as measured by magnetic resonance imaging and comparative methods /." Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4789-9/.
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Margaliot, Zvi. "Measurement of microvascular blood flow in skin and skeletal muscle using ultrasound contrast agents and a negative-bolus indicator-dilution technique." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0013/MQ50418.pdf.
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Österberg, Klas. "Vascular wall responses to bypass grafting : studies in mice /." Göteborg : Dept. of Molecular and Clinical Medicine, Vascular Surgery, Institute of Medicine, Sahlgrenska Academy at Göteborg University, 2008. http://hdl.handle.net/2077/9437.
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Diaz, Keith M. "Blood Pressure Variability: Relationship with Endothelial Health and Effects of an Exercise Training Intervention." Diss., Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/183386.
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KinesiologyPh.D.
Purpose: Evidence has accumulated to show that blood pressure variability (BPV) has a striking relationship with cardiovascular (CV) risk. Despite the mounting evidence implicating BPV as a CV risk factor, scant attention has been paid to: (1) the mechanisms by which high BPV confers greater CV risk; and (2) the efficacy of non-pharmacologic treatment modalities in the attenuation of BPV. In order to address these two unresolved questions, the purpose of this dissertation was twofold. The purpose of study #1 was to investigate the association between measures of short-term BPV (24-hour BPV) and long-term BPV (visit-to-visit BPV) with markers of endothelial health in a cohort of African Americans in order to determine if increased BPV may confer greater CV risk by eliciting injury to the endothelium. The purpose of study #2 was to investigate the effects of a 6-month aerobic exercise training (AEXT) intervention on visit-to-visit BPV and 24-hour BPV in the same cohort of African Americans in order to provide the first available data on the efficacy of a non-pharmacologic treatment modality in the lowering of BPV. Methods: We recruited 72 African Americans who were sedentary, non-diabetic, non-smoking, and free of CV and renal disease. Before and after a 6-month AEXT intervention, office blood pressure (BP) was measured at 3 separate visits and 24-hour ambulatory BP monitoring (ABPM) was conducted to measure visit-to-visit BPV and 24-hour BPV, respectively. Right brachial artery diameter was assessed at rest, during flow-mediated dilation (FMD), and after nitroglycerin-mediated dilation (NMD). Peak and area under the curve (AUC) were calculated as measures of FMD and NMD, and the FMD/NMD ratio was calculated as a measure of endothelial function normalized by smooth muscle function. Fasted blood samples were obtained and were analyzed for circulating EMPs expressed as CD31+CD42- and CD62E+ EMPs. Results: In study #1, participants with higher 24-hour diastolic BPV (DBPV) had significantly lower CD31+CD42- EMPs compared to participants with lower 24-hour DBPV. When categorized according to visit-to-visit DBPV, participants with higher visit-to-visit DBPV had a significantly lower FMD/NMD ratio, and significantly higher %NMDpeak and NMDAUCs compared to participants with lower visit-to-visit DBPV. When analyzed as continuous variables, 24-hour mean arterial pressure variability (MAPV) was inversely associated with CD31+CD42- EMPs visit-to-visit DBPV was inversely associated with the FMD/NMD ratio and positively associated with %NMDpeak and NMDAUC; and 24-hour DBPV was positively associated with NMDAUC. All associations were independent of age, gender, BMI, mean BP, and pulse pressure. In study #2 investigating the effects of AEXT in 33 participants who completed the study, 24-hour DBPV and 24-hour MAPV were significantly increased after AEXT. The increase in 24-hour DBPV was independent of changes in BMI, mean BP, and self-reported sleep time. Heart rate variability (HRV) derived from ABPM was associated with the changes in 24-hour DBPV and 24-hour MAPV. There were no significant changes in visit-to-visit BPV after AEXT. Conclusions: The results from study #1 provide evidence that BPV is associated with vascular health as endothelial function was decreased in participants with high visit-to-visit DBPV, while smooth muscle function was increased in participants with higher visit-to-visit and 24-hour DBPV. The findings from study #2 show that 6-months of AEXT do not elicit beneficial changes in BPV. The finding of an association between changes in 24-hour BPV with HRV could indicate, however, that changes in activity levels during ABPM, in part, contributed to the observed changes in 24-hour BPV.
Temple University--Theses