Superior parietal cortex has been implicated in visuomotor guidance and is proposed to be specialised for action in the lower visual field and peripersonal space. Two patients, one with a right superior parietal lesion leading to optic ataxia (ME), and one with a lesion affecting right inferior parietal cortex (LH), were compared to elderly controls (n=8) and young controls (n=8) on a reciprocal pointing task with movements made in the near-far direction (i.e., sagittal plane) or right-left direction (i.e., fronto-parallel plane). In contrast to both control groups, who demonstrated a speed-accuracy trade-off in movement time and peak velocity, neither of the patients did. When the time spent post-peak velocity (represented as a percentage of total movement time) was examined, both patients demonstrated larger times post-peak velocity than controls for all movement directions. Furthermore, while rightward movements of the right hand had higher times post-peak velocity than leftward movements there were no directional patterns for near-far movements which contrasted with controls who had larger times post-peak velocity for near movements. The patient with the more superior lesion (ME) had the greatest difficulty with movements made back toward the body suggestive of a role for superior parietal cortex in the fine tuning of movements made in this region of space (i.e., personal or peripersonal space). In contrast, all directions of movement seemed to be equally affected in the patient with a more inferior lesion. These results are discussed in terms of the different roles played by inferior and superior parietal cortex in the control of visually guided movements.

Platelet products have a short shelf life (5 to 7 days) owing in part to the deterioration of the quality of platelets stored at 22°C. This creates significant inventory challenges, and blood banks may suffer shortages and high wastage as a result. Proteomics offers a global quantitative approach to investigate changes occurring in stored blood products. These data sets can identify processes leading to storage-associated losses of blood component quality such as the platelet storage lesion (PSL). Changes to the platelet proteome between days 1 and 7 of storage were analysed with 3 complementary proteomic approaches with final mass spectrometric (MS) analysis: 2-dimensional (2D) gel electrophoresis/differential gel electrophoresis (DIGE), isobaric tagging for relative and absolute quantification (iTRAQ), and isotope-coded affinity tagging (ICAT). Although proteomics analyses identified many storage-associated protein changes, these varied significantly by method suggesting that a combination of protein-centric (2D gel or DIGE) and peptide-centric (iTRAQ or ICAT) approaches is necessary to acquire the most informative data. Validation of the proteomics results by western blotting, flow cytometry, quantitative real-time polymerase chain reaction (qRT PCR) and ³ٰ⁵S-methionine incorporation confirmed that platelets are capable of synthesising biologically relevant proteins ex vivo throughout a 10-day storage period with particularly long-lived mRNA (half-life of approximately 2.4 days), and has provided the first evidence for one of the mechanisms of the PSL. The development of an ³ٰ⁵Smethionine assay has since shown that stored human blood platelets incorporate ³ٰ⁵S-methionine at a rate that is proportional to time and substrate concentration, and is slower for freshly drawn platelets than those stored in pooled buffy coat derived units for 10 days. More interesting still are the observations that the overall ³ٰ⁵S-methionine incorporation rate was higher in pooled buffy coat platelet units versus freshly drawn platelets, that this rate increased upon agonist exposure in both, and that day 8 platelets showed significantly greater total protein translation than on days 2,3,7 and 10 of storage. This may be indicative of translational regulation of the platelet proteome during storage and upon activation. Translational control is a consequence of remarkable cellular specialisation and precise biochemical pathways which, in the case of platelets, may lead to storage-associated losses of blood component quality and must be understood if platelet storage times are to be extended.

Melanoma is the deadliest form of skin cancer if left untreated. Incidence rates of melanoma have been increasing, especially among young adults, but survival rates are high if detected early. Unfortunately, the time and costs required for dermatologists to screen all patients for melanoma are prohibitively expensive. There is a need for an automated system to assess a patient's risk of melanoma using photographs of their skin lesions. Dermatologists could use the system to aid their diagnosis without the need for special or expensive equipment. One challenge in implementing such a system is locating the skin lesion in the digital image. Most existing skin lesion segmentation algorithms are designed for images taken using a special instrument called the dermatoscope. The presence of illumination variation in digital images such as shadows complicates the task of finding the lesion. The goal of this research is to develop a framework to automatically correct and segment the skin lesion from an input photograph. The first part of the research is to model illumination variation using a proposed multi-stage illumination modeling algorithm and then using that model to correct the original photograph. Second, a set of representative texture distributions are learned from the corrected photograph and a texture distinctiveness metric is calculated for each distribution. Finally, a texture-based segmentation algorithm classifies regions in the photograph as normal skin or lesion based on the occurrence of representative texture distributions. The resulting segmentation can be used as an input to separate feature extraction and melanoma classification algorithms. The proposed segmentation framework is tested by comparing lesion segmentation results and melanoma classification results to results using other state-of-the-art algorithms. The proposed framework has better segmentation accuracy compared to all other tested algorithms. The segmentation results produced by the tested algorithms are used to train an existing classification algorithm to identify lesions as melanoma or non-melanoma. Using the proposed framework produces the highest classification accuracy and is tied for the highest sensitivity and specificity.

Platelet products have a short shelf life (5 to 7 days) owing in part to the deterioration of the quality of platelets stored at 22°C. This creates significant inventory challenges, and blood banks may suffer shortages and high wastage as a result. Proteomics offers a global quantitative approach to investigate changes occurring in stored blood products. These data sets can identify processes leading to storage-associated losses of blood component quality such as the platelet storage lesion (PSL). Changes to the platelet proteome between days 1 and 7 of storage were analysed with 3 complementary proteomic approaches with final mass spectrometric (MS) analysis: 2-dimensional (2D) gel electrophoresis/differential gel electrophoresis (DIGE), isobaric tagging for relative and absolute quantification (iTRAQ), and isotope-coded affinity tagging (ICAT). Although proteomics analyses identified many storage-associated protein changes, these varied significantly by method suggesting that a combination of protein-centric (2D gel or DIGE) and peptide-centric (iTRAQ or ICAT) approaches is necessary to acquire the most informative data. Validation of the proteomics results by western blotting, flow cytometry, quantitative real-time polymerase chain reaction (qRT PCR) and ³ٰ⁵S-methionine incorporation confirmed that platelets are capable of synthesising biologically relevant proteins ex vivo throughout a 10-day storage period with particularly long-lived mRNA (half-life of approximately 2.4 days), and has provided the first evidence for one of the mechanisms of the PSL. The development of an ³ٰ⁵Smethionine assay has since shown that stored human blood platelets incorporate ³ٰ⁵S-methionine at a rate that is proportional to time and substrate concentration, and is slower for freshly drawn platelets than those stored in pooled buffy coat derived units for 10 days. More interesting still are the observations that the overall ³ٰ⁵S-methionine incorporation rate was higher in pooled buffy coat platelet units versus freshly drawn platelets, that this rate increased upon agonist exposure in both, and that day 8 platelets showed significantly greater total protein translation than on days 2,3,7 and 10 of storage. This may be indicative of translational regulation of the platelet proteome during storage and upon activation. Translational control is a consequence of remarkable cellular specialisation and precise biochemical pathways which, in the case of platelets, may lead to storage-associated losses of blood component quality and must be understood if platelet storage times are to be extended.

Patients with skin lesions of the temple region that have spread to the parotid gland are commonly treated with three-dimensional conformal radiation therapy (3DCRT). 3DCRT has associated limitations when treating this disease. 3DCRT requires this disease site to be treated with two junction regions, resulting in poor dose conformity to the tumour target. Proximity of critical structures to the target volume can make dosimetry difficult, "especially for concave-shaped targets in close proximity to sensitive normal structures" (Saw.C et al., 2002, p76). Intensity modulated radiation therapy (IMRT) is a relatively new treatment technology that has potential to overcome limitations associated with 3DCRT (Garden.A et al., 2004). IMRT has been reported to have significant advantages over conventional 3DCRT treatment, by improving dose to the tumour and lowering doses to critical structures (Adams.E et al., 2001). Research has been conducted into the optimal IMRT treatment for specific head and neck carcinomas. They are identified as class solutions. "A class solution can be defined as the historical experience in designing RT plans for a particular site" (Intensity Modulated Radiation Therapy Collaborative Working, 2001, p913). This study was performed to establish an optimal IMRT class solution for patients with skin lesions of the temple region that have spread to the parotid gland, and to determine if it is the superior treatment option over 3DCRT treatment. Dosimetry planning was performed on computerised tomography data sets of nine patients with this disease site. One optimised 3DCRT dosimetry plan and eight optimised IMRT plans with specific beam arrangements were calculated. Clinical and statistical analysis was performed on; critical structures, conformity indices (CI) and dose volume histogram (DVH) range analysis of the planning target volume (PTV). Analysis of IMRT plans revealed that the 7-beam arrangement and 4-beam ipsilateral arrangement produced significantly lower doses to the majority of critical structures (P < 0.05). The 7-beam IMRT arrangement produced the best and second best CI and DVH PTV results, but these were not significantly different to the majority of other beam arrangements. This indicates that the 7-beam arrangement with defined beam angles of; 40°,120°,160°,200°,240°,300°,0°, is the superior IMRT treatment plan, and thus class solution for this disease site. Clinical analysis confirmed results. Analysis was performed on IMRT class solution results compared with 3DCRT results. CI was significance higher and DVH PTV range was significantly lower for the IMRT class solution (P < 0.05). The class solution delivered significantly higher doses to the majority of critical structures in comparison to the 3DCRT plan (P < 0.05). This indicates that the IMRT class solution is superior to 3DCRT in terms of PTV conformity and homogeneity, but not in terms of doses to critical structures. Skin lesions of the temple region with tumour extension to the parotid gland, is a complicated disease site. Investigations into current and potential radiation therapy treatments will guide treatment options and facilitate outcomes for patients with this disease.

In the adult central nervous system (CNS) several factors are implicated in the failure of neurons to regenerate after spinal cord injury (SCI). However, this reduced ability of injured CNS neurons to regenerate can be improved by under certain conditions. For instance, in adult dorsal root ganglion (DRG) neurons, injury to its peripheral branch (unilateral conditioning lesion) prior to injury of its central DRG branch (dorsal column cut) enhances the intrinsic capability of some but not all CNS afferent neurons to regenerate. The exact mechanism mediating this type of response is not known. However, previous studies by other groups have proposed that the regeneration of these CNS afferent neurons might be associated with the inflammatory response following injury to the peripheral DRG branch. Our general aim, was to examine the involvement of the immune response in the regeneration of the CNS DRG branch, as part of the pre-conditioned lesion model. To test this, three questions/hypotheses were investigated. Firstly, we investigated the effects of vaccination in pre-conditioned lesion animals using a peripheral nerve homogenate (PNH, sciatic nerve) as the immunogen. Given the regenerative capabilities of peripheral nerves, we proposed that exposure to this homogenate could enhance the limited regeneration of CNS fibres, after pre-conditioning of DRG neurons. Our results showed that in adult and/or neonatal Sprague Dawley (SD) rats PNH-vaccinated, had greater number of regenerated fibres, as compared to injury matched saline-vaccinated controls. Conversely, passive exposure to PNH through parental vaccination resulted in the suppression of this regenerative trigger. This suppressed competence of CNS fibres to regenerate was indirectly correlated with a reduced number of macrophage cells throughout the SCI epicentre, as compared to greater macrophage numbers found in the adult and/or neonatal treated groups. Secondly, we explored the possibility that a systemic inflammatory effect originating from the peripheral conditioning lesion, might be able to contribute to the regeneration of other injured neurons within the matured CNS. Again, using adult SD rats, we pre-conditioned the peripheral DRG branch as previous and changed the location of the CNS injury from the spinal cord to the optic nerve. Where alike any other injured neuron within the CNS, fails to regenerate. Unfortunately, our results from anterograde or retrograde labelling did not find any regenerated optic nerve fibres, although, we did find macrophage numbers to be higher in pre-conditioned lesion animals as compared to sham-operated animals. Therefore, it is possible that the pre-conditioning peripheral lesion might be allowing for a greater macrophage infiltration into the CNS compartment. Finally, we determined whether an early macrophage infiltration into the CNS compartment could be correlated with the observed CNS regeneration, characteristic of the pre-conditioned lesion model. To test this, we temporarily depleted macrophages before, during and after peripheral nerve lesion, via liposomal clodronate delivery. Our results from anterograde and retrograde labelling of spinal cord fibres revealed no regenerated CNS fibres in macrophage depleted animals, only in injury matched controls. In conclusion, macrophage cells play a beneficial role in the regeneration of CNS afferent fibres of pre-conditioned lesion DRG neurons. This most likely occurs through activation of intrinsic somatic DRG responses, as well as, an increased macrophage activation. We believe this inflammatory response to be of favourable phenotypic characteristic to the regeneration of injured CNS neurons, especially those in proximity to the DRG cell body. In addition, we propose that the conditioning peripheral lesion permits an influx of macrophage cells into the CNS compartment before injury of the CNS DRG branch, which is also likely to be supporting regeneration of afferent fibres. Future studies should evaluate the possibility that activated inflammatory cells might be infiltrating into the CNS under minimal blood-brain barrier disruption. It is clear that a complex communication between the nervous and immune system is occurring after the initial peripheral injury.

Made available in DSpace on 2014-06-11T19:30:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-06-09Bitstream added on 2014-06-13T19:00:27Z : No. of bitstreams: 1 sardenberg_j_dr_botfm.pdf: 1588012 bytes, checksum: 25f659fb0a5ae4d2f5ea55bb53dae425 (MD5) / Fundação para o Desenvolvimento Médico e Hospitalar (Famesp) / Há dúvidas em relação à melhor localização da sutura no reparo da lesão do tendão flexor dos dedos da mão, uma vez que o ponto central colocado na região dorsal vascularizada, apesar de gerar maior resistência que o ponto na região palmar, poderia, entretanto, interferir no suprimento sangüíneo do tendão. O objetivo da presente investigação foi avaliar, por meio da biomecânica e histopatologia, o efeito da sutura central na região de tendão normal vascularizada e na região de tendão fibrocartilaginoso avascular, no processo de cicatrização do tendão flexor profundo dos dedos do pé do coelho. Foram estudados 83 coelhos submetidos à sutura central tipo Kessler na região de tendão normal (grupo TN) e na região de tendão fibrocartilaginoso (grupo FC), completada com sutura periférica circunferêncial contínua. Após a cirurgia, o membro operado foi imobilizado pelo período de três semanas. Os animais foram sacrificados no período imediato, duas, três e seis semanas de pós-operatório. Concluiu-se que a colocação da sutura central na região de tendão normal vascularizada ou fibrocartilaginosa avascular não apresenta diferenças em relação aos aspectos biomecânicos e histopatológicos na cicatrização do tendão flexor profundo dos dedos do pé do coelho. / There are doubts concerning the best place for suture in repairing the lesion at flexor tendon of fingers. Although the core suture at vascular dorsal region generates more resistance than at palm region it may however interfere in tendon blood supply. The objective of the present research was to evaluate through biomechanics and histopathology the effect of core suture at vascular normal region of tendon as well as at avascular fibrocartilagenous tendon during healing of deep flexor tendon at rabbit toes. Eighty-tree animals were submitted to core Kessler suture at normal tendon region (NT group) as well as at fibrocartilagenous tendon region (FC group) completed with continuous circumferential periphery suture. After surgery the operated extremity was immobilized for a three weeks . The animals were sacrificed immediately and after two, three and six weeks of surgery. It was concluded that core suture at normal or fibrocartilagenous tendon region showed no differences concerning biomechanical and histopathological aspects in healing of deep flexor tendon of rabbit toes.

Platelet products have a short shelf life (5 to 7 days) owing in part to the deterioration of the quality of platelets stored at 22°C. This creates significant inventory challenges, and blood banks may suffer shortages and high wastage as a result. Proteomics offers a global quantitative approach to investigate changes occurring in stored blood products. These data sets can identify processes leading to storage-associated losses of blood component quality such as the platelet storage lesion (PSL). Changes to the platelet proteome between days 1 and 7 of storage were analysed with 3 complementary proteomic approaches with final mass spectrometric (MS) analysis: 2-dimensional (2D) gel electrophoresis/differential gel electrophoresis (DIGE), isobaric tagging for relative and absolute quantification (iTRAQ), and isotope-coded affinity tagging (ICAT). Although proteomics analyses identified many storage-associated protein changes, these varied significantly by method suggesting that a combination of protein-centric (2D gel or DIGE) and peptide-centric (iTRAQ or ICAT) approaches is necessary to acquire the most informative data. Validation of the proteomics results by western blotting, flow cytometry, quantitative real-time polymerase chain reaction (qRT PCR) and ³ٰ⁵S-methionine incorporation confirmed that platelets are capable of synthesising biologically relevant proteins ex vivo throughout a 10-day storage period with particularly long-lived mRNA (half-life of approximately 2.4 days), and has provided the first evidence for one of the mechanisms of the PSL. The development of an ³ٰ⁵Smethionine assay has since shown that stored human blood platelets incorporate ³ٰ⁵S-methionine at a rate that is proportional to time and substrate concentration, and is slower for freshly drawn platelets than those stored in pooled buffy coat derived units for 10 days. More interesting still are the observations that the overall ³ٰ⁵S-methionine incorporation rate was higher in pooled buffy coat platelet units versus freshly drawn platelets, that this rate increased upon agonist exposure in both, and that day 8 platelets showed significantly greater total protein translation than on days 2,3,7 and 10 of storage. This may be indicative of translational regulation of the platelet proteome during storage and upon activation. Translational control is a consequence of remarkable cellular specialisation and precise biochemical pathways which, in the case of platelets, may lead to storage-associated losses of blood component quality and must be understood if platelet storage times are to be extended. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate

Investigation of the neural correlates of the self has implicated a network of brain regions including the medial prefrontal cortex (MPFC), posterior cingulate (PCC), precuneus (pC), and inferior parietal lobule (IPL). At the same time, recent neuroimaging work has identified the Default Mode Network (DMN), a network of brain regions that are highly active at `rest' (without an active cognitive task). While the functional significance of the DMN remains unknown, converging evidence suggests that the DMN might be critical for self-referential processing (e.g., introspection). In this dissertation, I tested this hypothesis using a lesion approach. In the first experiment, I examined the critical role of the DMN hubs (MPFC, IPL) in autobiographical memory (AM) retrieval. I predicted that if the DMN hubs were critical for AM, then lesions to either the MPFC or IPL should result in AM retrieval impairments. I tested this prediction using the Iowa Autobiographical Memory Questionnaire (IAMQ), a questionnaire that assessed retrograde AM retrieval. In support of the prediction, lesions to the MPFC and IPL were associated with significant AM retrieval impairments. While not predicted, AM retrieval deficits were also associated with lesions in medial and lateral temporal cortices, regions also considered part of the DMN. In the second experiment, I tested the critical role of the DMN hubs in the self-reference effect (SRE), a well-known memory advantage conferred by self-related processing. I predicted that if the DMN hubs were critical for the SRE, then damage to the MPFC or IPL should diminish the effect. I used a standard personality trait judgment paradigm to test this prediction. In partial support of the prediction, I found that damage to the MPFC abolished the SRE with a "self" specific deficit. While IPL damage was associated with a diminished SRE, the effects were not significant. In the third experiment, I tested the hypothesis that the DMN is critical for accurate knowledge of one's personality. I predicted that if the DMN hubs are critical for accurate self-knowledge, then damage to either the MPFC or IPL should be associated with less accurate personality reports. In partial support of the prediction, MPFC and IPL groups demonstrated less accurate personality ratings. However, performance for all lesion groups was comparable and not significantly different from healthy subjects. In the fourth experiment, I sought to test the hypothesis that the DMN is critical for mind wandering (MW). I predicted that if the DMN hubs are critical for MW, then damage to the MPFC and IPL should result in decreased MW. To test this prediction, I used two approaches: 1) an experience sampling method (Sustained Attention to Response Task), and 2) a self-report measure (Imaginal Processes Inventory scale of MW). Contrary to my prediction, IPL lesions were associated with increased MW on the SART. By contrast, in support of the prediction, both MPFC and IPL lesions were associated with significant self-reported decreases in MW. Together, these experiments provide some evidence to support the hypothesis that the DMN is critical for self-referential processing. Future work might investigate the impact of DMN lesions on other self-processes (e.g., self-agency).

The molecular characterization of Pratylenchus species determined from D2-D3 of 28S rDNA, ITS of rDNA, and COI of mtDNA regions revealed four Pratylenchus species from North Dakota, P. scribneri, P. neglectus, Pratylenchus sp. (ND-2016 isolate HG51), and Pratylenchus sp. (ND-2017). They were clustered in four separate clades in the phylogenetic trees indicating the divergence among species. P. scribneri and Pratylenchus sp. (ND-2016 isolate HG51) were closely associated and Pratylenchus sp. (DH-2017) was closely related to Pratylenchus sp. (ND-2016 isolate HG51). However, P. neglectus was not closely associated with the other three species. Moreover, resistance evaluation of ten corn hybrids to Pratylenchus scribneri, P. neglectus, and Pratylenchus sp. (ND-2017) revealed that 1392 VT2P was moderately resistant to three Pratylenchus species. PFS74K89 and 4913 VT2RIB were moderately resistant to two of the three Pratylenchus species. X5B-8801, DK 43-46, and DKC 44-13 were susceptible to two of the three Pratylenchus species.