PART I: MARKERS OF INFLAMMATION IN DELAYED MUSCLE SORENESS Fifty-five untrained males were assigned to an experimental (E) or a control group (C), to re-examine the concept that DMS represents an acute inflammatory response. Subjects were assigned to receive either Indocin (Id; 100 mg per day) for 2 days prior to the treatment and a placebo (P) for 2 days after (Id-P); or the reverse combination (P-Id); or Id for- 4 days (Id-Id); or placebo (P-P). On the treatment day, to induce DMS, E subjects performed 30 min of bench-stepping with one leg leading throughout; C subjects rested for 30 min. Immediately before and after stepping/resting, all subjects used their right and left leg to perform 19 maximal and 15 submaximal repetitions on the Cybex II. Blood samples were collected -5 min before, immediately after bench stepping (0 h), 2 h after and 24, 48 and 72 h, to evaluate WBC. DMS was also monitored 0, 24, 48 and 72 h. All E subjects experienced a significant amount of DMS (p<.01) which peaked at 48 h after exercise (E=7.58 ± .79 vs 0 for C, X±SEM); however, no significant differences in soreness perception were observed between drug and placebo groups. Total WBC count ( cells/mm³ ) was significantly greater at 0 h (8,340±380) than at -5 min (6,699±365) for both E and C; this increase was most likely a response to Cybex exercise. At 2 h there was a significant increase in total WBC count for E ( 9,603±389) and no change for C ( 8,336±273}. Neutrophils increased significantly at 2 h for E only (6,428±375 vs 4,988±261 for C}. Bench-stepping leads to increases in DMS and increases in WBC count, particularly in neutrophils, 2 h after stepping; this data suggests that inflammation is involved in DMS. PART II: EFFECT OF AN ASPIRIN-LIKE DRUG ON PERCEIVED EXERTION DURING BENCH STEPPING The object of this study was to determine whether perceived exertion (RPE) for the limb performing predominantly positive work was significantly greater than for the limb performing predominantly negative work, during 30 min of bench stepping. A second objective was to determine the effects of indomethacin (Id) on RPE. Thirty-nine males were randomly assigned to a drug (Id) or placebo (P) group and administered 150 mg indomechacin or placebo, beginning 36 h prior to stepping. Results indicated no significant differences between RPE for "concentric" and "eccentric" limbs of the P group inspite of the fact that the metabolic demand of the "concentric" limb was much greater. Indomethacin did not significantly alter RPE during stepping however, when RPE scores were totaled over the entire bench stepping period, the Id condition was associated with a greater (p < .01) psychological cost for the "concentric" leg effort as compared to P; this indicated that indomethacin might alter effort sense related to concentric contractions. / Ph. D.

Kattaya-Annappa-Seema. / Thesis submitted in: December 2006. / "2+" and "+" in the title are superscripts. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 162-188). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.viii / Abstracts published based on work in this thesis --- p.ix / Table of contents --- p.x / Chapter Chapter 1: --- Introduction / Chapter 1.1 --- Pulmonary hypertension / Chapter 1.1.1 --- Pulmonary circulation and its functions --- p.1 / Chapter 1.1.2 --- Pulmonary vascular diseases and symptoms --- p.3 / Chapter 1.2 --- Muscarinic Receptor functions --- p.5 / Chapter 1.3 --- Acetylcholine (ACh) and its function --- p.7 / Chapter 1.4 --- ACh receptors in pulmonary vascular bed --- p.11 / Chapter 1.5 --- Potassium channel classification and functions --- p.12 / Chapter 1.5.1 --- "Importance of High-conductance, Ca2+ activated potassium channel (BKca) in vascular smooth muscle functions" --- p.15 / Chapter 1.5.2 --- Modulation of BKca channel by various cations --- p.18 / Chapter 1.6 --- Calcium signaling and homeostasis --- p.20 / Chapter 1.7 --- Role of sodium in hypertension --- p.22 / Chapter 1.8 --- Na+-H+ exchanger (NHE) functions --- p.25 / Chapter 1.9 --- Na+-Ca2+ exchanger (NCX) in vascular smooth muscle cells --- p.29 / Chapter 1.10 --- Spontaneously hypertensive rat (SHR) / Chapter 1.10.1 --- Hypertension in SHR --- p.32 / Chapter 1.10.2 --- BKca in smooth muscle vasculature of SHR --- p.33 / OBJECTIVES OF THE STUDY --- p.34 / Chapter Chapter 2: --- Material and methods / Chapter 2.1 --- Material / Chapter 2.1.1 --- Solutions and Drugs --- p.35 / Chapter 2.1.2 --- Chemicals and Enzymes --- p.39 / Chapter 2.2 --- Methods / Chapter 2.2.1 --- Isolation of single pulmonary arterial smooth muscle cells --- p.40 / Chapter 2.2.2 --- Electrophysiological measurement --- p.42 / Chapter 2.2.3 --- Data analysis --- p.44 / Chapter Chapter 3: --- Receptor-mediated activation of BKca Channel / Chapter 3.1 --- BKCa activation by ACh/ Carbachol (CCh) --- p.45 / Chapter 3.2 --- Role of extracellular sodium ([Na+]o）on BKca activation --- p.49 / Chapter 3.3 --- Receptor-mediated activation of BKca in a [Na+]o-containing solution --- p.51 / Chapter 3.4 --- Receptor-mediated activation of BKca in a [Na+]o-free solution --- p.55 / Chapter Chapter 4: --- Non-receptor mediated activation of BKCa Channel / Chapter 4.1 --- Effect of different concentrations of sodium nitroprusside (SNP) on BKCa activation --- p.60 / Chapter 4.2 --- Effect of SNP on BKca activation in a [Na+]o-containing and [Na+]o-free solutions --- p.62 / Chapter Chapter 5: --- Role of NHE in modulating activation of BKCa Channel / Chapter 5.1 --- Effect of Monensin on BKca activation / Chapter 5.1.1 --- Effect of monensin on CCh-mediated activation of BKca in a [Na+]o-containing solution --- p.70 / Chapter 5.1.2 --- Effect of monensin on CCh-mediated activation of BKca in a [Na+]o-free solution --- p.74 / Chapter 5.1.3 --- Effect of monensin on SNP- mediated activation of BKca in [Na+]o-containing and [Na+]o-free solutions --- p.78 / Chapter 5.2 --- Effect of 5-(N-ethyl-N-isopropyI) amiloride (EIPA) on BKCa activation / Chapter 5.2.1 --- Effect of EIPA on CCh-mediated activation of BKca in a [Na+]o-containing solution --- p.85 / Chapter 5.2.2 --- Effect of EIPA on CCh-mediated activation of BKca in a [Na+]。-free solution --- p.89 / Chapter 5.2.3 --- Effect of EIPA on SNP-mediated activation of BKCa in [Na+]o-containing and [Na+]o-free solutions --- p.93 / Chapter Chapter 6: --- Role of NCX in modulating activation of BKCa Channel / Chapter 6.1 --- Effect of KB-R7943 on CCh-mediated activation of BKCa in a [Na+]o-containing solution --- p.100 / Chapter 6.2 --- Effect of KB-R7943 on CCh-mediated activation of BKCa in a [Na+]o-free solution --- p.104 / Chapter 6.3 --- Effect of KB-R7943 on SNP-mediated activation of BKca in [Na+]o-containing and [Na+]o-free solutions --- p.109 / Chapter Chapter 7: --- Effect of intracellular sodium ([Na+]i) on BKCa channel activation / Chapter 7.1 --- Effect of CCh on BKCa channel activation with elevated [Na+]i pipette solution --- p.117 / Chapter 7.2 --- Effect of SNP on BKca channel activation with elevated [Na+]j pipette solution --- p.130 / Chapter Chapter 8: --- Discussion / Chapter 8.1 --- Modulatory effect of ACh and SNP --- p.138 / Chapter 8.2 --- Role of ion exchangers: NHE and NCX in modulating BKca channel function --- p.144 / Chapter 8.3 --- Modulatory effect of elevated [Na+]i on BKca activation --- p.153 / CONCLUSION --- p.161 / References --- p.162

Submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2014. / BACKGROUND Mechanical neck pain (MNP) has been described as any condition which changes joint mechanics and muscle structure / function. A review of the current literature shows that Muscle Energy Technique (MET) is an effective manual therapy for patients with acute or chronic MNP. The most useful contraction of MET however remains unknown. Some authors advocate the use of a two to seven second MET (Brous, 2005; Greenman, 2003 Mitchell, Moran, and Pruzzo, 1979) whilst other authors have recommended contraction durations of 30 to 60 seconds (Chaitow, 2006; Feland et al., 2001; Bandy and Irion, 1994). This study aimed to establish the most suitable contraction duration of MET in the treatment of chronic MNP by comparing a short duration MET to a long duration MET. OBJECTIVES Objectives included the comparison of a five-second (short duration) MET and a 45-second (long duration) MET in terms of subjective and objective findings in the treatment of chronic MNP. METHOD This randomized clinical trial, with 53 participants utilised a randomization table for group allocation. For the purpose of this study an average of the short contraction durations reported in the literature i.e. five seconds, was used for the short duration MET treatment and an average of the long contraction durations reported in the literature i.e. 45 seconds, was used for the long duration MET. Group A (n=26) received the five-second MET contraction and Group B (n=27) received the 45-second MET contraction treatment. Objective measures included the cervical range of motion (CROM Goniometer) and tenderness levels (algometer). The subjective measures were pain (Numerical Rating Scale-101) and MNP related disability (CMCC Neck Disability Index). Each participant received four treatments over a two week period, with all data collected prior to the first and third consultations and at the final follow up. Data were analysed using the SPSS version 20 (IBM), with a statistically significant p value set at <0.05. Repeated measures ANOVA testing determined the intergroup effects. To assess intergroup effects and effects of the intervention a time x treatment group interaction analysis was conducted. Profile plots assessed direction and trend of the effect of the treatment. RESULTS Intra-group analysis of both groups showed significant improvement in all of the range of motion measures (over time) except for Flexion, Right Lateral Flexion and Left Rotation in Group A and Flexion, Extension, Right Lateral Flexion and Left Lateral Flexion in Group B. The intra-group analysis also showed a significant improvement in the neck disability index scores and the tenderness measurements in both groups. The results of the inter-group analysis revealed that only Left Lateral Flexion showed a significant treatment effect (p=0.011) where increased scores were shown in Group A and not in Group B. There was no treatment effect for the neck disability index scores or the tenderness measurements. CONCLUSION It may be concluded that both treatment protocols were equally effective for all outcomes except for Left Lateral Flexion where the five-second MET seemed to show greater degree of improvement than the 45-second MET. The neck disability index scores and the pain levels of participants in both groups showed an improvement. No treatment was better than the other in terms of these two variables. This therefore seems to support the use of the shorter duration MET in clinical practice.

The purpose of this manuscript is to establish a unified theory of porohyperelasticity with transport and growth and to demonstrate the capability of this theory using a finite element model developed in MATLAB. We combine the theories of volumetric growth and mixed porohyperelasticity with transport and swelling (MPHETS) to derive a new method that models growth of biological soft tissues. The conservation equations and constitutive equations are developed for both solid-only growth and solid/fluid growth. An axisymmetric finite element framework is introduced for the new theory of growing MPHETS (GMPHETS). To illustrate the capabilities of this model, several example finite element test problems are considered using model geometry and material parameters based on experimental data from a porcine coronary artery. Multiple growth laws are considered, including time-driven, concentrationdriven, and stress-driven growth. Time-driven growth is compared against an exact analytical solution to validate the model. For concentration-dependent growth, changing the diffusivity (representing a change in drug) fundamentally changes growth behavior. We further demonstrate that for stress-dependent, solid-only growth of an artery, growth of an MPHETS model results in a more uniform hoop stress than growth in a hyperelastic model for the same amount of growth time using the same growth law. This may have implications in the context of developing residual stresses in soft tissues under intraluminal pressure. To our knowledge, this manuscript provides the first full description of an MPHETS model with growth. The developed computational framework can be used in concert with novel in-vitro and in-vivo experimental approaches to identify the governing growth laws for various soft tissues.

Title: Effect of water temperature on the electrical activity of muscle Objective: Main objective of this work is to determine the spatiotemporal changes in muscle activation depending on different properties of the environment. All this at a defined muscle power output. Measured by hand dynamometer. Methods: This is a case study. Is processed and analyzed the relationship of the forearm muscles against the aquatic environment (different temperatures - 15 řC, 24 řC and 35 řC) and against dry. Muscular power output is defined and measured by hand dynamometer. Muscular power output was determined as isometric contraction flexors of wrist and fingers of dominant hand. It all in three different modes. The research group were included 5 healthy individuals (3 women, 2 men). As objectivization method was determined surface electromyography. Findings: There is no influence of water temperature (15 řC, 24 řC and 35 řC) on spatiotemporal activation of muscle. It all at a defined muscle power output. There is also no changes on spatiotemporal activation of muscle in aquatic and dry. Keywords: muscle contraction, temperature, water environment, surface electromyography, Water Surface EMG

O complexo troponina-tropomiosina regula a contração muscular esquelética e cardíaca. A ligação do cálcio nos sítios regulatórios localizados no domínio N-terminal da troponina C (TnC) induz uma mudança conformacional que remove a ação inibitória da troponina I (TnI) e inicia a contração muscular. Nós usamos fragmentos recombinantes da TnI e uma série de mutantes da TnC para estudar as interações estruturais e regulatórias das diferentes regiões da TnI com os domínios da TnC, TnT e actina-tropomiosina. Nossos resultados indicam que a TnI é organizada em regiões que apresentam funções estruturais e regulatórias e que se ligam de modo antiparalelo com os correspondentes domínios estruturais e regulatórios da TnC. Estudos funcionais mostram que a região inibitória (aminoácidos 103-116) em combinação com a região C-terminal da TnI (TnI103-182) pode regular a atividade ATPásica da acto-miosina de maneira dependente de Ca2+. A regulação não é observada com a região inibitória em combinação com a região N-terminal (TnI116) Estudos de ligação mostram que a região N-terminal da TnI (TnI1-98) interage com o domínio C-terminal da TnC na presença e na ausência de Ca2+ e também interage com a TnT. A região inibitória/C-terminal da TnI (TnI103-182) interage com o domínio N-terminal da TnC de maneira dependente de Ca2+. Baseados nestes resultados, propomos um modelo para a mudança conformacional induzida pelo Ca2+. Neste modelo, a região N-terminal da TnI está ligada fortemente com o domínio C-terminal da TnC na presença ou na ausência de Ca2+. As regiões inibitórias e C-terminal da TnI ligam-se à actina-tropomiosina na ausência de Ca2+ e nos domínios N-terminal e C-terminal da TnC na presença de Ca2+. / The troponin-tropomyosin complex regulates skeletal and cardiac muscle contraction. Calcium binding to the regulatory sites in the N-terminal domain of troponin C (TnC). induces a conformational change which removes the inhibitory action of troponin I (TnI) and initiates muscular contraction. We used recombinant TnI fragments and a series of TnC mutants to study the structural and regulatory interactions between different TnI regions and the domains of TnC, TnT and actin-tropomyosin. Our results indicate that TnI is organized into regions with distinct structural and regulatory functions which bind, in an antiparallel manner, with the corresponding structural and regulatory domains of TnC. Functional studies show that a fragment containing the inhibitory and C-terminal regions of TnI (TnIl03-182) can regulate the actomyosin ATPase in a Ca2+- dependent manner. Regulation was not observed with a fragment containing the N-terminal and inhibitory regions (TnIl-116). Binding studies show that the N-terminal region of TnI (TnI1-98) interacts with the C-terminal domain of TnC in the presence of Ca2+ or Mg2+. The inhibitory/C-terminal region of TnI (TnI103-182) binds to the N-terminal domain of TnC in a Ca2+-dependent manner. Based on these results, we propose a model for the Ca2+ -induced conformational change. In this model the N-terminal region of TnI is bound strongly to the C-terminal domain of TnC in the presence or absence of Ca2+. The inhibitory and C-terminal regions of TnI bind to actin-tropomyosin in the absence of Ca2+ and to tne N- and C-terminal domains of TnC in the presence of Ca2+.

A number of studies have investigated the relationship between surface electromyogram (EMG) and torque exerted about a joint. The standard deviation of the recorded EMG signal is defined as the EMG amplitude. The EMG amplitude estimation technique varies with the study from conventional type of processing (i.e. rectification followed by low pass filtering) to further addition of different noise rejection and signal-to-noise ratio improvement stages. Advanced EMG amplitude processors developed recently that incorporate signal whitening and multiple-channel combination have been shown to significantly improve amplitude estimation. The main contribution of this research is a comparison of the performance of EMG-torque estimators with and without these advanced EMG amplitude processors. The experimental data are taken from fifteen subjects that produced constant-posture, non-fatiguing, force-varying contractions about the elbow while torque and biceps/triceps EMG were recorded. Utilizing system identification techniques, EMG amplitude was related to torque through a zeros-only (finite impulse response, FIR) model. The incorporation of whitening and multiple-channel combination separately reduced EMG-torque errors and their combination provided a cumulative improvement. A 15th-order linear FIR model provided an average estimation error of 6% of maximum voluntary contraction (or 90% of variance accounted for) when EMG amplitudes were obtained using a four-channel, whitened processor. The equivalent single-channel, unwhitened (conventional) processor produced an average error of 8% of maximum voluntary contraction (variance accounted for of 68%). This study also describes the occurrence of spurious peaks in estimated torque when the torque model is created from data with a sampling rate well above the bandwidth of the torque. This problem is anticipated when the torque data are sampled at the same rate as the EMG data. The problem is resolved by decimating the EMG amplitude prior to relating it to joint torque, in this case to an effective sampling rate of 40.96 Hz.

A motricidade orofacial é a especialidade da Fonoaudiologia, que tem como objetivo a prevenção, diagnóstico e tratamento das alterações miofuncionais do sistema estomatognático. Atualmente, muitos pesquisadores desta área, nacional e internacionalmente, têm buscado metodologias mais objetivas de avaliação e conduta. Dentre tais aparatos está a eletromiografia de superfície (EMG). A EMG é a medida da atividade elétrica de um músculo. Os objetivos deste trabalho foram o de identificar, por meio da EMG, a atividade elétrica dos músculos faciais de adultos saudáveis durante movimentos faciais normalmente utilizados terapeuticamente na clínica fonoaudiológica, para identificar o papel de cada músculo durante os movimentos e para diferenciar a atividade elétrica destes músculos nestes mesmos movimentos, bem como avaliar a validade da EMG na clínica fonoaudiológica. Foram avaliadas 31 pessoas (18 mulheres) com média de idade de 29,48 anos e sem queixas fonoaudiológicas ou odontológicas. Os eletrodos de superfície bipolares foram aderidos aos músculos masseteres, bucinadores e supra-hióides bilateralmente e aos músculos orbicular da boca superior e inferior. Os eletrodos foram conectados a um eletromiógrafo EMG 1000 da Lynx Tecnologia Eletrônica de oito canais, e foi pedido que cada participante realizasse os seguintes movimentos: Protrusão Labial (PL), Protrusão Lingual (L), Inflar Bochechas (IB), Sorriso Aberto (SA), Sorriso Fechado (SF), Lateralização Labial Direita (LD) e Esquerda (LE) e Pressão de um lábio contra o outro (AL). Os dados eletromiográficos foram registrados em microvolts (RMS) e foi considerada a média dos movimentos para a realização da análise dos dados, que foram normalizados utilizando como base o registro da EMG no repouso e os resultados demonstram que os músculos orbiculares da boca inferior e superior apresentam maior atividade elétrica que os outros músculos na maior parte dos movimentos, com exceção dos movimentos de L e SF, Nos movimentos de LD e LE, os orbiculares da boca também estavam mais ativos, mas os músculos bucinadores demonstraram participação importante, especialmente o bucinador direito em LD A Protrusão Lingual não demonstrou diferenças significativas entre os músculos estudados. O SA teve maior participação do orbicular da boca Inferior que o superior, e demonstrou ser o movimento que mais movimenta os músculos da face como um todo e o músculo com maior atividade durante o SF foi o bucinador. Concluímos que o aparato da EMG é eficiente não só para a avaliação dos músculos mastigatórios, mas também dos da mímica, a não ser no movimento de Protrusão lingual, onde o EMG de superfície não foi eficiente. Os músculos orbiculares foram mais ativos durante os movimentos testados, portanto, são também os mais exercitados durante os exercícios de motricidade oral. O movimento que envolve a maior atividade dos músculos da face como um todo foi o Sorriso Aberto / Speech Therapy has been considered subjective during many years due to its manual and visual methods. Many researchers have been searching for more objective methodology of evaluation, based on electronics devises. One of them is the EMG- Surface Electromyography, which is the electric unit measure of a muscle. Literature presents many works in TMJ and Orthodontics areas, special attention to the chewing muscles- temporal and masseter- for been bigger muscles, presenting more evident results in EMG. Less attention is paid for mimic muscles. The objective of our work is to identify, by means of EMG, the electrical activity of facial muscles of healthy adults during facial movements normally used in speech therapy clinic, to identify the role of each muscle during movements and to differentiate the electrical activity of these muscles during this movements. 31 volunteers have been evaluated (18 women) with mean age of 29,84 years, no speech therapy or odontological complains. Bipolar surface electrodes have been adhered to masseter, buccinator and suprahyoid muscles bilaterally and to superior and inferior orbicular oris muscles. Electrodes were connected to a EMG 1000 from Lynx Tecnologia Eletrônica of 8 channels, and it was asked each participant to carry out the following movements: Labial Protrusion (PL), Lingual Protrusion (L), Cheek Inflating (CI), Opened Smile (OS), Closed Smile (CS), Labial Lateralization (LL) and pressure of one lip against the other (LP). EMG data was registered in microvolts (RMS) and the movement media was considered for data analyses, which were normalized using as bases the rest EMG and results show that orbicular oris are more electric activity than other muscles in PL, CI, OS, LL and LP. In LL movements, orbicularis oris also showed greater activity, but buccinator muscles showed effective participation in movement, especially in right LL. L didnt show any differences between evaluated muscles. Buccinator was the most active muscle during CS. We concluded that Orbicularis Ores were the most active muscles during the tasks, exception made to L and CS. In L no muscle was significantly higher and in CS Buccinators were the most active. Opened Smile is the movement where the muscles are more activated in a role. This results shows that EMG is of great use for mimic muscles evaluation, but should be used carefully in specific tongue assessment

From animal experimentation, and studies using in vitro models, there was evidence in the literature to suggest that dietary fibre may influence contractility and motility of the gastrointestinal tract and long chain (LC) n-3 polyunsaturated fatty acids (PUFAs) from marine sources may influence contractility of smooth muscle cells in blood vessels. The hypothesis of this thesis was that dietary fish oil and/or fibre influence the contractility of isolated intact sections of gut smooth muscle tissue from small animal models. Methodology was established to measure in vitro contractility of intact pieces of guinea pig ileum with the serosal side isolated from the lumen. It was demonstrated that four amino acid peptides from κ-casein (casoxins) applied to the lumen overcame morphine-induced inhibition of contraction. Using this established technology, the guinea pig was used to investigate the effects of dietary fibre and fish oil supplementation on gut in vitro contractility. In separate experiments, changes in sensitivity to electrically-driven and 8-iso-prostanglandin (PG)E₂-induced contractility were demonstrated for dietary fibre and fish oil. A modified, isolated gut super-perfusion system was then established for the rat to validate these findings. It was subsequently shown that LC n-3 PUFA from dietary fish oil significantly increased maximal contraction in response to the G-protein coupled receptor modulators, acetylcholine and the eicosanoids PGE₂, PGF₂α, 8-iso-PGE₂ and U-46619 in ileum but not colon, without changes in sensitivity (EC₅₀), when n-3 PUFA as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) had been incorporated to a similar degree into the gut total phospholipid membrane pool. It was further established that the spontaneously hypertensive rat (SHR) had a depressed prostanoid (PGE₂and PGF₂α) response in the gut that could be restored by dietary fish oil supplementation (5% w/w of total diet) in the ileum but not the colon. Importantly, the muscarinic response in the colon of the SHR was increased by fish oil supplementation with DHA likely to be the active agent. Dietary fish oil dose experiments deduced differential increases in response occurred at fish oil concentrations of 1% for muscarinic and 2.5% (w/w) for prostanoid stimulators of the ileum with no difference in receptor-independent KCl-induced depolarization-driven contractility. Studies combining high amylose resistant starch (HAMS, 10% w/w) and fish oil (10% w/w) fed to young rats demonstrated a low prostanoid response that was enhanced by dietary fish oil but not resistant starch. There was however, an interactive effect of the HAMS and fish oil noted for the muscarinic-mimetic, carbachol. Generally, resistant starch increased the large bowel short chain fatty acid pool with a subsequent lower pH. Binding studies determined that while the total muscarinic receptor binding properties of an isolated ileal membrane fraction were not affected in mature rats by dietary fish oil, young rats had a different order of muscarinic receptor subtype response with a rank order potency of M₃ > M₁ > M₂ compared to mature animals of M₃ > M₂ > M₁ with fish oil altering the sensitivity of the M₁ receptor subtype in isolated carbachol-precontracted ileal tissue. In conclusion, experiments using the guinea pig and rat gut models demonstrated that dietary fish oil supplementation, and to a lesser degree fibre, increased receptor-driven contractility in normal and compromised SHR ileum and colon. Further, changes in responsiveness were demonstrated in the developing rat gut prostanoid and muscarinic receptor populations that could be altered by dietary fish oil. Preliminary evidence suggested that fish oil as DHA may alter receptor-driven gut contractility by mechanisms involving smooth muscle calcium modulation. Defining the role that dietary fibre and fish oil, and other nutrients, play in normal and diseased states of bowel health such as inflammatory bowel disease (IBD), where contractility is compromised, are among the ongoing challenges. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1316907 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008

The aim of this project was to produce and study a murine homozygous knock-in model containing a fast skeletal regulatory light chain (RLC) containing a Asp49toAla point mutation. The D49A mutation is in the functional calcium binding loop of RLC, which is believed to modulate muscle contraction in striated muscle. To introduce the mutation, a reversible knock-out/knock-in system was employed. The Cre/Lox-P strategy was used to conditionally knock-in the RLC D49A mutation. The generation of the knock-in mouse was attempted with two different breeding strategies consisting of two Cre mouse lines with differential expression patterns during development. The proposed animal was never produced because the RLC knock-out recombination event introduced a splicing error resulting in a stop codon in intron 2. Extensive DNA, RNA and protein analysis as well as histological, gross morphology and muscle physiology studies obtained from the animals of the two breeding strategies lead to the identification of the splicing error. Evidence for this outcome is presented. A recommendation for a different strategy in future studies is included.