The innervation of the small blood vessels

Thesis (M.A.)--Boston University, 193

The small blood vessels of the mammal

Thesis (M.A.)--Boston University, 1944. This item was digitized by the Internet Archive

Formation, growth, degeneration and regeneration of small blood vessels

Thesis (M.A.)--Boston University, 1948. This item was digitized by the Internet Archive

Computational Non-Newtonian Hemodynamics of Small Vessels

The significance of non-Newtonian hemodynamics of small blood vessels is addressed via the description and critical discussion of cogent models within Computational Fluid Dynamics (CFD) software, in this case ANSYS-CFX. Several applicable hemodynamical shear-thinning models are presented and the relevance with respect to prediction of Shear Strain Rate (SSR) rigorously examined, in order to critically evaluate salient literature. It is found that the small vessels explored, in line with the aforementioned literature, that non-Newtionian evaluation of the fluid behavior is indeed negligible. The work presented herein is a precursor to investigation of more complex geometries and hemodynamic simulations, which are being actively researched. This is a technical note which attempts to address the significance of Newtonian/non-Newtonian flows in small blood vessels

Studying macro- and microvascular responses to major surgery to develop preventive strategies for perioperative complications

Complications occur in up to 70% of patients undergoing surgery and may lead to further morbidity or even mortality. Systemic and local inflammatory processes in small and large blood vessels can cause such complications and therapeutic strategies are required for their prevention or treatment. In this thesis, we focused on understanding and targeting processes that cause inflammation after surgery in large and small blood vessels. We showed that a sharp drop in high-density lipoprotein cholesterol was strongly associated with the occurrence of heart attacks in patients undergoing vascular surgery. Further, we demonstrated smaller plaques in a model of atherosclerosis-prone mice that were lacking the protein Regulator of G Protein Signalling 5, which modulates processes for signal transduction within cells. To elucidate the inflammatory processes in small blood vessels, we generated a model to expose endothelial cells to patient plasma, obtained before and after surgery, under altered blood flow conditions. Furthermore, we identified the protein tyrosine kinases Axl and Fyn as therapeutic targets in microvascular endothelial inflammation induced by the acutely elevated pro-inflammatory mediator Tumour Necrosis Factor . Overall, our aim was to perform studies which can be used to develop strategies to prevent complications after surgery. We used laboratory animal and cell culture models in combination with patient data and materials to improve the current understanding of therapeutic targets for complications after surgery in both large and small blood vessels. While we cannot offer a solution to these problems, we identified multiple possible therapeutic targets that now require further investigations

The small blood vessels in areas of lymphocytic infiltration around malignant neoplasms.

LYMPHOCYTIC INFILTRATES have been described in association with many different human non-lymphoid malignant neoplasms (Underwood, 1974) and in a few, such as medullary carcinoma of the breast, are characteristic of the tumour. Many investigators have reported an association between improved prognosis and lymphocyte infiltration (Bloom et al., 1970

Studying macro- and microvascular responses to major surgery to develop preventive strategies for perioperative complications

Complications occur in up to 70% of patients undergoing surgery and may lead to further morbidity or even mortality. Systemic and local inflammatory processes in small and large blood vessels can cause such complications and therapeutic strategies are required for their prevention or treatment. In this thesis, we focused on understanding and targeting processes that cause inflammation after surgery in large and small blood vessels. We showed that a sharp drop in high-density lipoprotein cholesterol was strongly associated with the occurrence of heart attacks in patients undergoing vascular surgery. Further, we demonstrated smaller plaques in a model of atherosclerosis-prone mice that were lacking the protein Regulator of G Protein Signalling 5, which modulates processes for signal transduction within cells. To elucidate the inflammatory processes in small blood vessels, we generated a model to expose endothelial cells to patient plasma, obtained before and after surgery, under altered blood flow conditions. Furthermore, we identified the protein tyrosine kinases Axl and Fyn as therapeutic targets in microvascular endothelial inflammation induced by the acutely elevated pro-inflammatory mediator Tumour Necrosis Factor . Overall, our aim was to perform studies which can be used to develop strategies to prevent complications after surgery. We used laboratory animal and cell culture models in combination with patient data and materials to improve the current understanding of therapeutic targets for complications after surgery in both large and small blood vessels. While we cannot offer a solution to these problems, we identified multiple possible therapeutic targets that now require further investigations

Adaptive clutter filter design for micro-ultrasound color flow imaging of small blood vessels

In micro-ultrasound, which uses imaging frequencies above 20 MHz, obtainingcolor flow images (CFI) of small blood vessels using is not a trivial taskbecause it is more challenging to suppress tissue clutter properly given thestronger blood signal power at high imaging frequencies and the slow bloodvelocity inside the microcirculation. To improve clutter suppression inmicro-ultrasound CFI, this paper presents an adaptive clutter filtering approachthat is based on a two-stage eigen-analysis of slow-time ensemblecharacteristics. The approach first identifies tissue pixels in the imaging viewby examining whether high-frequency contents are absent in the principalslow-time eigen-components for each pixel as computed from single-ensembleeigen-decomposition. It then computes the filtered slow-time ensemble for eachpixel by finding the least-squares projection residual between the pixel'sslow-time ensemble and the clutter eigen-components estimated from amulti-ensemble eigen-decomposition of tissue slow-time ensembles within aspatial window. In this filtering approach, the clutter eigen-components arechosen based on whether their mean frequency lies within a spectral band. Toanalyze the efficacy of the proposed adaptive filter, both in-vitro experimentsand Field II simulations were carried out. For the experiments, raw CFI datawere acquired using a 64-element, 33 MHz linear array prototype (pulse duration:2 cycles, PRF: 1 kHz, transmit focus: 8mm, F-number: 5). Their imaging viewcorresponded to the cross-section of a 0.9mm-diameter tube that was placed ontop of an unsuspended table where ambient vibrations may appear; flow velocity(5, 7, 10, 15 mm/s) within the tube was controlled using a syringe pump. For thesimulations, raw CFI data was computed for both plug and parabolic flowprofiles, and tissue motion was modeled as 0.5 mm/s sinusoidal vibrations. Forall flow velocities tested in our in-vitro study, the proposed adaptive filterimproved the flow detection sensitivity as compared to existing ones. In theslow-flow case (5 mm/s), we observed over 70% increase in flow detectionsensitivity (assuming a 5% false alarm rate). This effectively reduced flashingartifacts in the resulting CFIs and gave a more consistent visualization of theflow tube. © 2010 IEEE.published_or_final_versionThe 2010 IEEE International Ultrasonics Symposium, San Diego, CA.,, 11-14 October 2010. In Proceedings of IEEE IUS, 2010, p. 1206-120