A Study of the Factors Which Affect the Growth of Tumour Cells at Distant Sites

The aim of this thesis is to investigate some of the factors which affect the growth of metastasising cells at distant sites. Previous experiments, mostly involving intravenous injection of cultured murine B16 melanoma and other tumour cell lines, have suggested that subpopulations of cells exist within tumours which are capable of metastasis, sometimes to specific organs. One criticism of these studies is that growth at a distant site is but one characteristic required for a cell to successfully form a metastatic deposit. The cell must also express other phenotypic characteristics such as motility and invasion and in some cases evasion of host defences. Much of the experimental work in this thesis makes use of the B16 melanoma F10 and F1 cell lines. The F10 cell line was derived many years ago by repeated in vivo passage through the lungs of syngeneic mice while the F1 cell line was passaged in vivo only once and has been maintained exclusively in vitro. In this study it was found that the F10 cell line formed tumours at a high rate, exclusively in the lungs, whereas the F1 cell line was much less metastatic and selective in its site of growth. The use of radio-labelled cells showed that the F10 cells were more avidly trapped in the lungs than the F1 cells but the difference in lung trapping between the two cell lines was less marked than the difference in lung tumour formation. These results broadly confirm the results of earlier studies and show that despite prolonged culture the cell lines have been stable with respect to these properties. In contrast to the results of intravenous injection, when F1 and F10 cells were injected into the peritoneal cavity it was found that there was no difference in the number of tumours produced. Each cell line was then subjected to repeated intraperitoneal passage to see whether passaged cells formed more local tumours when injected peritoneally, whether such cells would home to the peritoneal cavity following intravenous injection, and if passage in the peritoneum would effect lung homing properties particularly of the F10 cell line. After 16 passages an F10 cell line was produced which grew more readily in the peritoneal cavity but did not produce abdominal tumours when injected intravenously: lung tumour formation was unaffected. When F1 cells were passaged it was found that after 8 passages cell growth in vitro and in the peritoneal cavity was so greatly reduced that in only one of three sets of experiments was it possible to proceed beyond the eighth passage. The set of F1 cells which reached passage 16 continued to show poor growth in vitro and after intraperitoneal injection but surprisingly produced a much larger number of lung tumours following intravenous injection than the parent cell line. This latter change was not accompanied by increased cell trapping in the lungs. By way of comparison a benign virus-induced salivary tumour was studied. This model was limited by failure to culture the tumour cells in vitro. When a cell suspension derived from this tumour was injected intraperitoneally no tumours resulted. Thus the benign nature of this tumour may have been partly due to an inability to grow at a distant site. An attempt was made to correlate adhesion of B16 and salivary tumour cells to tissue sections with their sites of growth but in contrast to previous studies no such correlation was found. Mechanisms to account for these results are discussed with particular reference to the effects of selection, trapping by the vasculature and the influence exerted by local tissue environments on tumour cells. While these mechanisms are often difficult to separate experimentally there was some evidence that local environments may play a larger part than hitherto realised in controlling the growth of metastasising tumour cells. Little is known of the molecular basis of tumour cell metastasis, though attempts to identify cell surface proteins and more recently the genes involved in the process have met with some success. Since the histo-compatability proteins are known to participate in a wide range of cellular interactions, they may be involved in the process of metastatic tumour growth. (Abstract shortened by ProQuest.)

Anisotropic expansion of a thermal dipolar Bose gas

We report on the anisotropic expansion of ultracold bosonic dysprosium gases at temperatures above quantum degeneracy and develop a quantitative theory to describe this behavior. The theory expresses the post-expansion aspect ratio in terms of temperature and microscopic collisional properties by incorporating Hartree-Fock mean-field interactions, hydrodynamic effects, and Bose-enhancement factors. Our results extend the utility of expansion imaging by providing accurate thermometry for dipolar thermal Bose gases, reducing error in expansion thermometry from tens of percent to only a few percent. Furthermore, we present a simple method to determine scattering lengths in dipolar gases, including near a Feshbach resonance, through observation of thermal gas expansion.Comment: main text and supplement, 11 pages total, 4 figure

Reduced-Order Aerothermoelastic Framework for Hypersonic Vehicle Control Simulation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83643/1/AIAA-2010-7928-117.pd

Multi-Channel Stochastic Variational Inference for the Joint Analysis of Heterogeneous Biomedical Data in Alzheimer's Disease

The joint analysis of biomedical data in Alzheimer's Disease (AD) is important for better clinical diagnosis and to understand the relationship between biomarkers. However, jointly accounting for heterogeneous measures poses important challenges related to the modeling of the variability and the interpretability of the results. These issues are here addressed by proposing a novel multi-channel stochastic generative model. We assume that a latent variable generates the data observed through different channels (e.g., clinical scores, imaging, ...) and describe an efficient way to estimate jointly the distribution of both latent variable and data generative process. Experiments on synthetic data show that the multi-channel formulation allows superior data reconstruction as opposed to the single channel one. Moreover, the derived lower bound of the model evidence represents a promising model selection criterion. Experiments on AD data show that the model parameters can be used for unsupervised patient stratification and for the joint interpretation of the heterogeneous observations. Because of its general and flexible formulation, we believe that the proposed method can find important applications as a general data fusion technique.Comment: accepted for presentation at MLCN 2018 workshop, in Conjunction with MICCAI 2018, September 20, Granada, Spai

Building an IDE for an embedded system using web technologies

Implementing an understandable, accessible and effective user interface is a major challenge for many products in the microcontroller and embedded computing community. Bela, an embedded system for ultra-low latency audio and sensor processing, features a browser-based integrated development environment (IDE) using web technologies (Node.js, HTML5 and CSS). This methodology has allowed us to create an IDE that is simplified and intuitive for beginners while still being useful to those more advanced, thus supporting users as they evolve in expertise

Peripheral Nerve Tumors in Neurofibromatosis 1, Neurofibromatosis 2, and Schwannomatosis

Neurofibromatosis was first described in the nineteenth century. At the time, Friederich Daniel Von Recklinghausen detailed two cases of multiple neurofibromas. Although reports of similar cases had been published before his, Von Recklinghausen is credited with the initial description in 1882, postulating that the tumors originated from nerve sheath and plexal connective tissue. Similarly, in 1822 John Henry Wishart described what is believed to be neurofibromatosis type 2; however, it was Harvey Cushing’s description of a case of bilateral vestibular schwannomas in 1916 that highlighted and increased awareness of the disease (albeit the original presentation was thought to be in the context of neurofibromatosis type 1). Since their original description, understanding of these neurocutaneous diseases has greatly expanded. Knowledge of the genotypic mutations and molecular mechanisms underlying the disease pathophysiology has resulted in natural history enlightenment and optimal treatment refinement. However, many aspects of neurofibromatosis have yet to be explained and remain active areas of investigation. In this chapter, clinical, radiological, and surgical considerations for peripheral nerve tumor management in the context of neurocutaneous disorders are reviewed. More specifically, clinical presentations, pathological and imaging findings, as well as management for neurofibromatosis type 1, type 2, and schwannomatosis are comprehensively discussed

Radiological data of brachial plexus avulsion injury associated spinal cord herniation (BPAI-SCH) and comparison to anterior thoracic spinal cord herniation (ATSCH).

Spinal cord herniation (SCH) is a rare cause of myelopathy. When reported, SCH has most commonly been described as occurring spontaneously in the thoracic spine, and being idiopathic in nature (anterior thoracic spinal cord herniation, ATSCH) [1-3]. Several theories have been proposed to explain its occurrence, including congenital, inflammatory, and traumatic etiologies alike [1-4]. Even more rarely, SCH has been described to occur in the cervical spine in association with brachial plexus avulsion injuries (BPAI-SCH). In our accompanying article, Late Cervical Spinal Cord Herniation Resulting from Post-Traumatic Brachial Plexus Avulsion Injury, two cases of BPAI-SCH are presented and discussed in the context of the reviewed literature [5]. Here, pertinent accompanying follow-up data was collected and is presented for the cases, including postoperative radiographic outcome imaging. Furthermore, a table is presented comparing and contrasting ATSCH to BPAI-SCH. Although the two phenomena have been previously grouped together, this table highlights ATSCH and BPAI-SCH as distinct entities; more specifically, BPAI-SCH is a separate, long-term complicating feature of BPAI. This supplementary data helps treating physicians by increasing awareness and knowledge of BPAI-SCH as a distinct entity from ATSCH and cause of delayed neurological deterioration