Introduction The transverse abdominal plane (TAP), formed between the transversus abdominis muscle (TAM) and the internal oblique muscle (IOM), contains the thoracolumbar nerve plexus. The plexus is anaesthetised through a blind or ultrasound-guided TAP block, mainly used for post-operative pain management. Ultrasounds are not always readily available in the public sector, creating a need to improve the blind TAP block. The L1 nerve and its terminal branches, also running in the TAP, can be blocked with a TAP block or separately. By studying the anatomy of the nerve plexus, the TAP block and the iliohypogastric and ilioinguinal blocks could be improved. This study aimed to determine the course and branching patterns of the thoracolumbar nerve plexus, as well as the branching of the L1 nerve in the posterior abdominal wall before entering the TAP. Methods Bilateral dissections were done on 54 embalmed cadavers to examine the TAP by noting the number of nerves at the mid-axillary line (MAL) and at the linea semilunaris. The needle tip position, as well as the general branching patterns were evaluated. For the L1 dissections, the root contributions and branching patterns were evaluated before entering the TAP. Abdominal ultrasounds were taken bilaterally on 43 volunteers to measure depth, individual muscle layer thickness, and subcutaneous fat thickness on a line at the injection point and at the IOM and TAM tendon junction. Differences between sides and the effect of BMI categories were analysed. Results The average number of nerves from the MAL to the linea semilunaris increased by one nerve. The needle was in the correct plane in only 7.6% of cases, with the needle going too deep in 79.3% of cases. The pop method used in the blind TAP block ensures the needle tip is not too superficial, but it is easy to go deeper than required. A nerve was pierced in 6.5% of cases, while the mean distance between the needle tip and the closest nerve (4.56 mm 6.83 mm) indicated the needle tip is generally close enough to the nerves to provide anaesthesia without nerve damage. Nerve interactions observed includes branching or not, merging or not, or any combination thereof. Various variations were seen for the root contributions of the L1 nerve, affecting the innervation of the anterolateral abdominal wall. The fourth lumbar artery accompanied the L1 or its terminal branches to enter the TAP in 40.7% of cases. The IOM and TAM tendon junction appears as a hyperechoic dot on an ultrasound, which can be used as an additional landmark. Measurements revealed the needle should be advanced at least 2 cm and 3 cm in healthy and overweight BMI individuals respectively. Conclusions Notable differences were seen between the current study and studies using a different population, indicating the anatomy of the TAP block is specific to population. The anatomy surrounding the TAP showed significance for a South African population. By analysing the anatomy, this study adds ways to improve the blind and ultrasoundguided TAP blocks. / Dissertation (MSc)--University of Pretoria, 2015. / Anatomy / MSc / Unrestricted

Joint hypermobility (JH) in its various forms is in many ways misinterpreted and underdiagnosed. As a symptom of heritable disorders of connective tissue (HDCT), it is well known, whilst understanding around JH as a non-symptomatic occurrence in physically active populations is vague at best. With literature suggesting associations between JH and musculoskeletal injury (MSI), an inherent risk for populations undergoing intense physical training (PT) is implied. This dissertation set out to shed light on the incidence of hypermobility in a South African context, whilst seeking to clarify the implications of JH on intense PT and vice versa. The research was conducted by employing an in depth literature review on the broad spectrum of physiological factors linked to hypermobility, along with three comprehensive scientific studies which answered definitive questions relating to the paper s main research objectives. In investigating the causative factors of JH, literature indicated congenital amino-acid substitutions in collagen synthesis which compromises the molecular nano-mechanics of connective tissues, thus negating the structural integrity of collagen containing compounds such as tendons, ligaments, joint capsules, skin, demineralised bone and nerve receptors. This concept, along with current thinking which suggests that the shape of bones and low muscle tone may also contribute to hypermobility, clearly indicates compromised joint biomechanics in hypermobile individuals. A commonly linked neurologic factor of hypermobility i.e. diminished joint proprioceptive acuity, lead to our proposed concept of a closed cycle of causative vs. symptomatic factors, which perpetuates abnormal articular biomechanics. The initial study which sought to investigate the incidence rates of hypermobility in the general South African population, employed a cross-sectional research approach with a sample population of 480 individuals from four wide-spread geographical areas. Individuals were tested for JH according to the Beighton nine-point hypermobility score with a diagnostic criteria of 4/9 or greater. Results indicated a 26.19% overall incidence of JH, with sex specific totals showing a 36.41% incidence for females compared to 13.96% for males. Thus concurring with contemporary studies indicating a significantly high prevalence of JH in the general population. The second study which concerned the interactions between muscular component and hypermobility, correlated Beighton nine-point hypermobility scores and lean body mass (LBM) at three intervals during a 20 week intense training intervention period in a military sample. Linear regressions indicated a significant correlation between increased LBM and associated decreases in hypermobility, even though hypermobility peaked after 12 weeks of intense exercise. We proposed that the hypermobility peak leading up to week 12 can be clarified by initial training induced generalized flexibility, neural adaptation of exercise which increases ROM amongst other factors. In aiming to clarify one of the most prevalent discussions in hypermobility research i.e. the association between JH and MSI, the final study compared MSI incidences between hypermobile and non-hypermobile individuals who endured 20 weeks of intense military basic training protocols. Odds ratios indicated that hypermobile individuals are 1.8 times more likely to sustain MSI when undergoing intense physical activity. Chi-square tests indicated a marginal, though significant association between JH and MSI. Ulterior results showed increased MSI prevalence amongst females as well as no significant difference in MSI location distribution amongst the hypermobile and control groups. In considering all our findings we concluded that JH is an underdiagnosed common occurrence in the South African general population. The congenital influences on connective tissue development in hypermobile individuals sufficiently undermines musculoskeletal integrity to the extent where they are susceptible to increased risk of injury when participating in intense physical activity. These debilitating mechanisms can however be counteracted by the implementation of specific exercises promoting joint stabilization, proprioceptive acuity and increased muscular component. / Dissertation (MSc)--University of Pretoria, 2015. / Physiology / MSc / Unrestricted

The obturator nerve sends both motor and sensory fibres to the medial compartment of the thigh. This study aimed to provide a clear description of the anatomy and course of the obturator nerve and its branches to assist surgeons and clinicians in the safe performance of various pelvic procedures One hundred and one (101) formalin-fixed cadavers 61 males and 40 females (68 ± 17 years), were dissected at the Department of Anatomy, University of Pretoria. Dissections were performed just lateral to the lumbar vertebra to describe the origin of the obturator nerve. The course of the nerve, with its relations, was observed and recorded until it terminated in the medial thigh. The location of the obturator nerve within the obturator foramen was quantified by measuring the distance from three (3) bony landmarks of the obturator foramen to the nerve; most superior, most medial and most inferior points. The results were used to determine their possible clinical applications. Variations were observed in the root origins of the obturator nerve, its course in the abdomen, bifurcation patterns and the innervation patterns of its terminal branches. The obturator nerve (B) was found 6.26 ± 1.62 mm from the most superior point (A), 31.69 ± 3.41 mm from the most medial point (C) and 47.33 ± 3.94 mm from most inferior point (D). The measurement from the obturator nerve to the most inferior point (B-D) is the one with a significant difference for sex (p = 0.26). The results may be used in the pre-operative preparation of pelvic lymphadenectomy, stress urinary incontinence (SUI) treatment and obturator nerve blocks. The study has assisted in expanding the knowledge on the anatomy of the obturator nerve and its branches in a South African context. These results should be verified in a clinical setting. / Dissertation (MSc)--University of Pretoria, 2015. / Anatomy / MSc / Unrestricted

Genetic diversity is a well-described concept within many biological disciplines. However, mathematical models determining genetic diversity are often applied within ecological disciplines and are rarely explored within the medical field. Given that genetically associated disorders and complications can occur at high frequency in developing countries, the primary aim of this study was to determine whether or not diversity theory could be applied to disease-associated variants. Two monogenic disorders were selected for this purpose one commonly observed disorder known as cystic fibrosis (CF), and one rare disorder known as metachromatic leukodystrophy (MLD). Despite being a common monogenic disorder, the clinical and molecular presentation of CF in the different population groups of South Africa is largely unknown. Thus, the medical records of 45 CF patients attending the Steve Biko Academic Hospital CF clinic were investigated to better understand the manifestation of this disorder in these patients. Additionally, molecular data was collected for both CF and MLD through published reports and analysed via the Shannon-Weaver, Simpson, Simpson Diversity, and rarefaction diversity methods. The rarefaction method was found to be the most informative measure of diversity and a potentially powerful tool to employ in the development and/or refinement of population-specific screening panels. / Dissertation (MSc)--University of Pretoria, 2015. / Immunology / MSc / Unrestricted

Exercise scientists and coaches frequently base physical conditioning objectives on the nature and magnitude of the physiological demands imposed by competitive events. Part of this demand may be characterized by the extent and proportion of aerobic and anaerobic energy supply associated with performing an athletic task. Maximum effort rowing imposes severe physiological demands owing to high force application per stroke, extensive skeletal muscle involvement, and repetition of a unique movement pattern, distinguishing it somewhat from other endurance exercise modalities. Rowing ergometry represents a valid and reliable simulation of the biomechanical and physiological demands of on-water rowing, and the 2000 m rowing ergometer time trial has become a standard physical performance test for rowers. However, empirical information regarding proportional aerobic and anaerobic energy supply during maximum effort 2000 m rowing is scarce. Studies which have investigated the theme report a proportional dominance (70-90%) by aerobic energy supply, but the research studies are limited in number and dissimilar in methodology. Further, models of relative energy system contribution popularized in traditional textbooks frequently do not mirror the results of these studies. The accumulated oxygen (O2) deficit (AOD) method, despite limitations, remains a preferred method for differentiating aerobic and anaerobic energy supply during dynamic, whole-body exercise in athletes, yet few AOD measurements have been made on rowers during 2000 m rowing ergometer time trials. Also, while several anthropometric and physiological characteristics have long been shown to be associated with rowing performance, relationships between energy system contributions and performance do not appear to have been investigated to date. The purpose of this study was to quantify the relative energy system contributions during a maximum effort 2000 m rowing ergometer time trial, and to determine the correlations between performance and measures of aerobic and anaerobic energy supply. A quantitative, cross-sectional research study was designed to obtain descriptive and correlational data from a sample of elite oarsmen during a single observation period. Twentyfive national and international level male rowers (mean ± standard deviation [SD] age: 21.0 ± 3.6 years, rowing training history: 5.7 ± 3.4 years, maximum O2 uptake [VO2max]: 4.64 ± 0.54 L·min-1 or 58.9 ± 5.3 ml·kg-1·min-1) from the South African national rowing squad volunteered as participants. In the first of two separate test sessions within a period spanning no more than five days, participants underwent anthropometric assessment (body mass: 78.9 ± 7.6 kg, stature: 185.2 ± 5.5 cm, sum-of-seven skinfolds: 53.6 ± 9.8 mm) and completed a 2000 m time trial (performance time: 405.6 ± 20.5 s, range: 373.0-452.0 s) on a Concept II rowing ergometer. The second session involved an incremental rowing ergometer exercise test including five or six submaximal intensity stages spanning the range 35-85% of time trial average power output, and a maximum effort stage to determine peak power output and VO2max. Pulmonary O2 uptake (VO2) was recorded continuously during exercise via open-circuit spirometry. Aerobic energy supply was determined from accumulated O2 uptake during the time trial, while anaerobic energy supply was calculated from the AOD. Specifically, incremental exercise test data was used to establish the VO2-power output relationship (R2: 0.995 ± 0.004, SEE: 0.061 ± 0.028 L·min-1) for each participant, which was solved for average power output to yield the total equivalent O2 demand of the 2000 m time trial. The difference between accumulated O2 uptake and total equivalent O2 demand represented the AOD. Descriptive statistics were used to report physiological responses and measures of aerobic and anaerobic energy supply, while Spearman rank order correlation coefficients (rho) were calculated to evaluate the relationships between energy system measures and 2000 m time trial performance. The principal finding of this study was in agreement with earlier research reports that aerobic and anaerobic energy supply respectively represented 80-82% (range: 73-93%) and 18-20% (range: 7-27%) of total energy cost during a maximum effort 2000 m rowing ergometer time trial. Notably, relative energy system contribution showed considerable variation among participants which could not be fully explained by differences in exercise duration, since the correlations between time trial performance and energy system fractional contributions, while significant (P < 0.05), were not strong (rho: 0.5-0.6). While significant relationships were also found between 2000 m performance time and age, rowing training history, body mass, stature, accumulated O2 uptake and AOD, only VO2max and peak VO2 (VO2peak) expressed in absolute terms, peak power output, and total equivalent O2 demand demonstrated strong (rho: 0.82-0.96) correlations with 2000 m rowing ergometer performance time. Aerobic energy supply dominates total energy provision during a maximum effort 2000 m rowing ergometer time trial, with VO2 reaching rates exceeding 97% of VO2max. However, AOD values recorded in this study (6.10 L O2 eq or 76.9 ml O2 eq·kg-1) support the argument that 2000 m rowing involves extensive utilization of anaerobic capacity. So while aerobic energy supply dominates proportionally, the absolute values of aerobic and anaerobic energy supply reported here underscore the large cumulative energy demand imposed by a 2000 m rowing ergometer time trial. Significant relationships commonly observed between rowing performance and rower characteristics, including measures of body size and endurance fitness, were corroborated by this study. However, the ability to produce and sustain a high power output during rowing, necessarily supported by the capacity for high absolute rates of both aerobic and anaerobic energy supply regardless of their respective contributions was the bioenergetic capability most strongly related to performance in a 2000 m rowing ergometer time trial in this study. Improved understanding of aerobic and anaerobic energy supply during simulated rowing races such as the 2000 m rowing ergometer time trial has practical utility for exercise scientists and coaches in terms of rower identification and management, as well as in the planning, regulating and monitoring of rowing training programmes. Future investigations should consider assessing seasonal changes in the relative energy system contributions for a 2000 m rowing ergometer time trial, and distribution of aerobic and anaerobic energy supply in relation to the regulation of power output (pacing) during simulated rowing races. / Dissertation (MSc)--University of Pretoria, 2015. / Physiology / MSc / Unrestricted

Objectives: This in vitro study investigated and compared the fracture strength and behaviour patterns of a conventional posterior composite resin, a composite resin reinforced with nano-scale electrospun glass-fibres and a conventional composite resin placed on a fibre substructure, all used in cusp-replacing posterior composite resin restorations. Methods: Seventy-five extracted, lower, left, first and second molars were prepared to accept standardized restorations replacing the mesio-lingual cusp. The specimens were randomly divided into 3 groups of 25 each: Group A (control) was restored with a conventional posterior composite resin, Group B was restored with the composite resin reinforced with nano-scale electrospun glass fibres and Group C was restored with a conventional posterior composite resin reinforced with a fibre substructure. All restored specimens were thermocycled for 500 cycles between 5° C and 55° C with a dwell time of 30 seconds, then imbedded in plastic cylinders in acrylic resin. The specimens were loaded at a 30° angle to the long axis of the tooth, using a jig mounted in a universal testing machine until fracture occurred. Fracture strength was recorded and specimens were then stained to highlight fracture patterns and subsequently studied under a microscope. Fractures were classified as restorable/non-restorable. Sub-classification included adhesive and cohesive failures. Results: Compared to Group A both techniques of fibre inclusion significantly strengthened the cusp-replacing composite restoration (ANOVA p = 0.05) Compared to Groups A and B the group of restorations placed on a fibre sub-structure (Group C) exhibited significantly more fractures that were classed as restorable. Compared to Group A and C the group restored with the composite resin reinforced with nano scale electrospun glass fibres (Group B) displayed significantly more fractures that were classed as non-restorable (Fisher s Exact Test p = 0.05). Conclusion: Both fibre inclusion techniques significantly strengthened cuspreplacing posterior composite restorations. Fracture behaviour patterns differed significantly between the two fibre-strengthening techniques. / Dissertation (MSc)--University of Pretoria, 2015. / Odontology / MSc / Unrestricted

Introduction South Africa is ranked the third most obese country after the United States of America and Great Britain. According to a study conducted by the South African Medical Research Council, 61% of the South African population is overweight, obese, or severely obese. Research into obesity and its contributing factors has increased as the problem continues to increase on a global scale. Adipose-derived stromal/stem cells (ASCs), formerly known as mesenchymal stem cells (MSCs), are obtained from adipose tissue and have self-renewal properties and multipotential capabilities. A subpopulation of these cells with stem cell characteristics has the potential to differentiate down the adipogenic lineage. This provides a human primary cell model to study the mechanisms of adipogenesis including hyperplasia (cell number proliferation and/or differentiation) and hypertrophy (cell size increase due to lipid droplet accumulation). The stromal/stem cells are said to reside in hypoxic niches where the physiological O2 tension is lower than ambient O2 tension (21% O2) and thus oxidative stress may be reduced. Obesity is correlated with increased oxidative stress and chronic inflammation. Inflammation is associated with the generation of ROS and the accumulation of ROS leads to oxidative stress. ROS is also important in signal transduction pathways. Adipogenesis is triggered by signaling molecules leading to the conversion of a subpopulation of ASCs to preadipocytes, which further differentiate into mature adipocytes. Differentiation down specific lineages coincides with the migration of these stromal/stem cells out of the hypoxic niche. This motivated the assessment of the effect of oxidative stress and a hypoxic mimetic, Dimethyloxalylglycine (DMOG) on adipogenesis in vitro. Methods ASCs were induced to differentiate into adipocytes using adipogenic-inducing medium. The use of the pro-oxidant, H2O2, and the antioxidants, Trolox and CoQ10 allowed for the modulation of ROS in the ASC cultures. Hypoxia was mimicked by the addition of DMOG to ASCs that were induced to differentiate into adipocytes. The adipogenic differentiation was quantitatively detected using flow cytometry and the emission profiles of Nile Red. Results It was demonstrated that ROS added exogenously to adipogenic-induced ASCs enhanced adipogenesis. It was also observed that H2O2 added to non-induced ASCs caused lipid accumulation. Trolox and CoQ10 attenuated the increase in ROS and thus a decrease in adipogenesis was seen. Removal of pyruvate, a ROS scavenger, was necessary to see these effects. The addition of DMOG resulted in a trend towards the reduction in adipogenesis over the 14 and 21-day induction periods. Conclusion ASCs provide a primary cell model for investigating adipogenesis and the effects of oxidative stress and hypoxia on this process. This is relevant for many diseases and therapeutic options. The study also showed that flow cytometry is a powerful technique that can aid in the quantitative detection of adipogenesis and the cell sub-populations that make up this process. This research underscores the importance of assessing the effects of both oxidative stress and hypoxia on adipogenesis at a gene and protein level in the future. / Dissertation (MSc)--University of Pretoria, 2015. / Immunology / MSc / Unrestricted

Tracheal cuff pressure monitoring plays a significant role in the care of patients in the critical care environment. Most patients in critical care environment are intubated with cuffed tubes via the ore or the naso-tracheal route, or a tracheostomy is performed. The purpose of the tracheal cuff is to maintain a seal between the tube and the tracheal wall, to prevent volume loss and ensure effective mechanical ventilation. Nurse practitioners in the critical care environment play a vital role in monitoring tracheal cuff pressure, which is often neglected in clinical practice. Purpose: To investigate the effect of an intervention on tracheal cuff pressure monitoring in the critical care environment of an academic hospital in Gauteng. Design and methods: A quantitative prospective non-experimental comparative design, with a collaborative qualitative method. The study had a pre and post intervention phase to compare the effect on an intervention. Findings: The study findings during the pre-intervention phase revealed inconsistency in the monitoring, night time monitoring poor and the found and the adjusted pressure documentation poor. Most pressures found to be non-compliant and serious non-compliant. The post-intervention results revealed an improvement in the night monitoring, but pressures were still found to be high. The consistency in the frequency of monitoring remains poor. Recording of the found and adjusted pressure had a small improvement. Conclusion: Inconsistent cuff pressure monitoring is done in the critical care environment. Comparing the continuous pressure monitoring, it shows that the frequency of monitoring need to be re-looked. Continuous in-service training may have an effect on the practice and the use of reminders can have an impact in the practice. Frequent clinical audits need to be conducted in order to evaluate practice and have plans for improvement. Clinical relevance: If the practice of tracheal cuff pressure monitoring can be done according to the revised guidelines, there might be an improved outcome of patients in the critical care environment and reduced costs. / Dissertation (MCur)--University of Pretoria, 2015. / Nursing Science / MCur / Unrestricted

This study intended to examine the individual effect of hippotherapy on Physiological Cost Index and school activities in adolescents with diplegia. Ten adolescents with diplegia, aged 12 to 16 years, were studied. The results were not to be generalised to the broader cerebral palsy population. A triangulation mixed method design was used. Within the quantitative part of the study, a single system multiple baseline design across subjects was implemented and in the qualitative part of the study, a semi-structured interview was used to determine effect of hippotherapy on school activities. Individual hippotherapy was conducted once a week over a 12-week period. The effect of hippotherapy on physiological cost index was inconclusive, but the results obtained with regards to an increase in walking speed, were statistically significant. Out of the qualitative research, three themes emerged as an effect of hippotherapy on school activities, namely improved rest and sleep, improved functional ambulation, and improved neuro-musculoskeletal functioning. / Dissertation (MOccTher)--University of Pretoria, 2015. / Occupational Therapy / MOccTher / Unrestricted

Objectives: To evaluate the surface roughness of a nanocomposite and a microhybrid composite after polishing the composites with different polishing systems. Key words: Polishing, surface roughness, microhybrid composite, nanocomposite, Sof-Lex XT, Spiral Wheels, Enhance, Intensiv UniglossCellbrush, Zircon-Brite, Dura-White stones, Mylar strips Methods: The composites used in this study were Filtek Supreme XTE (3M ESPE, St Paul, USA) and Z100 (3M ESPE, St Paul, USA). Thirty-five composite samples were made from each of the two composites. Uncured composite was placed into an aluminium ring mould, 10mm X 2mm. Both the upper and lower surfaces of the composite were covered with Mylar strips and glass plates, before the specimens were cured for 40 seconds from both sides. Samples were randomly divided into seven groups. The groups were: 1. Mylar polyester strip (control) 2. Sof-Lex XT finishing and polishing discs (3M ESPE, St Paul, USA) 3. Sof-Lex Spiral Wheels (3M ESPE, St Paul, USA) 4. Dura-White stones (Shofu Inc, Kyoto, Japan) 5. Intensiv UniglossCellbrush (Intensiv SA, Montagnola, Switzerland) 6. Enhance finishing and polishing system (Dentsply, Milford, USA) 7. Sof-Lex Spiral Wheels combined with Zircon-Brite (Dental Ventures of America, Corona, USA) The polishing of the specimens was performed by a single operator according to manufacturer s instructions. The mean surface roughness of each specimen was determined using a profilometer (Surftest SJ 210, Mitutoyo, Tokyo, Japan). Three readings were collected from each specimen. Data was statistically analysed using ANOVA. Scanning Electron Microscope (JEOL JSM-5800 LV, Tokyo, Japan) photos were taken of the representative samples. Results: Statistically significant differences in surface roughness were observed between the following groups: Z100 and Filtek Supreme XTE with the polishing systems combined (p=0.005); Control group vs all the polishing systems; Sof-Lex XT finishing and polishing discs vs Dura-White stones, Intensiv UniglossCellbrush, Enhance finishing and polishing system (p < 0.0001); Sof-Lex Spiral Wheels vs Dura-White stones, Intensiv Unigloss Cellbrush, Enhance finishing and polishing system (p <0.0001); Dura-White stones vs Intensiv UniglossCellbrush, Enhance finishing and polishing system, Sof-Lex Spiral Wheels/Zircon-Brite (p <0.0001); Intensiv UniglossCellbrush vs. Spiral Wheels/Zircon-Brite (p<0.0001); Enhance finishing and polishing system vs. Spiral Wheels/Zircon-Brite (p <0.0001). Conclusion: Filtek Supreme XTE displayed significantly better polishability and lower surface roughness values after polishing than Z100. The composite samples cured against the Mylar polyester strip produced significantly smoother surface roughness values than all the polishing systems tested in this study. The following polishing systems led to the smoothest surfaces after polishing: Sof-lex Spiral Wheels in combination with Zircon-Brite, as well as the Sof-Lex Spiral Wheels and Sof-Lex finishing and polishing discs. These systems were significantly smoother than the Enhance system used in combination with Prisma Gloss polishing paste, and also the one-step polishing system Intensiv UniglossCellbrush. There was no statistically significant difference between Sof-Lex Spiral Wheels in combination with Zircon-Brite, the Sof-Lex Spiral Wheels and the Sof-Lex finishing and polishing discs. / Dissertation (MSc)--University of Pretoria, 2015. / Odontology / MSc / Unrestricted