The relative contributions of carotid duplex scanning, magnetic resonance angiography, and cerebral arteriography to clinical decisionmaking: A prospective study in patients with carotid occlusive disease

AbstractPurpose: Recent reports suggest that 80% to 90% of patients can safely undergo carotid endarterectomy on the basis of duplex scanning alone without cerebral angiography. Other investigators have recommended that a complementary imaging study such as magnetic resonance angiography (MRA) also be obtained.Methods: We prospectively evaluated 103 consecutive patients with carotid occlusive disease. Eighty percent of patients were symptomatic. All 103 patients underwent duplex scanning and arteriography. Additional noninvasive tests included computed tomography, magnetic resonance imaging, and MRA in 50%, 56%, and 48% of patients, respectively. At a multispecialty conference all studies except angiograms were reviewed, and a treatment decision was made by a panel of attending vascular surgeons, neurosurgeons, and neurologists. The cerebral angiograms then were reviewed and changes made to final treatment plans were noted.Results: After review of noninvasive studies, 30 of 103 of patients (29%) were believed to require arteriography because of diagnostic uncertainty of carotid occlusion in three patients, suggestion of nonatherosclerotic disease in four, suggestion of proximal disease in two, suboptimal noninvasive studies in one, and uncertainty of therapy despite good-quality noninvasive studies in 20 patients primarily with borderline stenoses and unclear symptoms. In 10 of these 30 patients (33%) management decisions were changed on the basis of angiogram results. Of the remaining 73 patients (71%) in whom the panel felt comfortable proceeding with operative or medical therapy without angiography, only one patient (1.4%) would have had management altered by results of angiography. MRA results concurred with duplex findings in 92% of studies, but did not alter management in any patient.Conclusions: In patients with good-quality duplex images, focal atherosclerotic bifurcation disease, and clear clinical presentation, treatment decisions can be made without arteriography. In 30% of patients angiography is useful in clarifying decisionmaking. MRA is unlikely to influence management decisions and is thus rarely indicated. (J Vasc Surg 1996;23:950-6.

Extracellular matrixâ based scaffolding technologies for periodontal and periâ implant soft tissue regeneration

The present article focuses on the properties and indications of scaffoldâ based extracellular matrix (ECM) technologies as alternatives to autogenous soft tissue grafts for periodontal and periâ implant plastic surgical reconstruction. The different processing methods for the creation of cellâ free constructs resulting in preservation of the extracellular matrices influence the characteristics and behavior of scaffolding biomaterials. The aim of this review is to discuss the properties, clinical application, and limitations of ECMâ based scaffold technologies in periodontal and periâ implant soft tissue augmentation when used as alternatives to autogenous soft tissue grafts.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153617/1/jper10427.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153617/2/jper10427_am.pd

Biologicsâ based regenerative technologies for periodontal soft tissue engineering

This manuscript provides a stateâ ofâ theâ art review on the efficacy of biologics in root coverage procedures, including enamel matrix derivative, plateletâ derived growth factor, platelet concentrates, and fibroblastâ growth factorâ 2. The mechanism of action and the rationale for using biologics in periodontal plastic surgery, as well as their anticipated benefits when compared with conventional approaches are discussed. Although the clinical significance is still under investigation, preclinical data and histologic evidence demonstrate that biologicâ based techniques are able to promote periodontal regeneration coupled with the provision of tooth root coverage.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154295/1/jper10426_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154295/2/jper10426.pd

Autogenous soft tissue grafting for periodontal and periâ implant plastic surgical reconstruction

This stateâ ofâ theâ art review presents the latest evidence and the current status of autogenous soft tissue grafting for soft tissue augmentation and recession coverage at teeth and dental implant sites. The indications and predictability of the free gingival graft and connective tissue graft (CTG) techniques are highlighted, together with their expected clinical and esthetic outcomes. CTGs can be harvested from the maxillary tuberosity or from palate with different approaches that can have an impact on graft quality and patient morbidity. The influence of CTGs on soft tissue thickness and keratinized tissue width are also discussed.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153773/1/jper10428_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153773/2/jper10428.pd

Living cellâ based regenerative medicine technologies for periodontal soft tissue augmentation

The cultivation of human living cells into scaffolding matrices has progressively gained popularity in the field of periodontal wound healing and regeneration. Living cellular constructs based on fibroblasts, keratinocytes alone or in combination have been developed and used as alternatives to autogenous soft tissue grafts in keratinized tissue augmentation and in root coverage procedures. Their promising advantages include reduced patient morbidity, unlimited graft availability, and comparable esthetics. This manuscript reviews soft tissue augmentation and root coverage procedures using bioengineered living cellular therapy and highlights their expected clinical, esthetic, and patientâ related outcomes.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154237/1/jper10429.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154237/2/jper10429_am.pd

The potential of label-free nonlinear optical molecular microscopy to non-invasively characterize the viability of engineered human tissue constructs

AbstractNonlinear optical molecular imaging and quantitative analytic methods were developed to non-invasively assess the viability of tissue-engineered constructs manufactured from primary human cells. Label-free optical measures of local tissue structure and biochemistry characterized morphologic and functional differences between controls and stressed constructs. Rigorous statistical analysis accounted for variability between human patients. Fluorescence intensity-based spatial assessment and metabolic sensing differentiated controls from thermally-stressed and from metabolically-stressed constructs. Fluorescence lifetime-based sensing differentiated controls from thermally-stressed constructs. Unlike traditional histological (found to be generally reliable, but destructive) and biochemical (non-invasive, but found to be unreliable) tissue analyses, label-free optical assessments had the advantages of being both non-invasive and reliable. Thus, such optical measures could serve as reliable manufacturing release criteria for cell-based tissue-engineered constructs prior to human implantation, thereby addressing a critical regulatory need in regenerative medicine

Coronagraphic Wavefront Control for the ATLAST-9.2m Telescope

The Advanced Technology for Large Aperture Space Telescope (ATLAST) concept was assessed as one of the NASA Astrophysics Strategic Mission Concepts (ASMC) studies. Herein we discuss the 9.2-meter diameter segmented aperture version and its wavefront sensing and control (WFSC) with regards to coronagraphic detection and spectroscopic characterization of exoplanets. The WFSC would consist of at least two levels of sensing and control: (i) an outer coarser level of sensing and control to phase and control the segments and secondary mirror in a manner similar to the James Webb Space Telescope but operating at higher temporal bandwidth, and (ii) an inner, coronagraphic instrument based, fine level of sensing and control for both amplitude and wavefront errors operating at higher temporal bandwidths. The outer loop would control rigid-body actuators on the primary and secondary mirrors while the inner loop would control one or more segmented deformable mirror to suppress the starlight within the coronagraphic field-of view. Herein we discuss the visible nulling coronagraph (VNC) and the requirements it levies on wavefront sensing and control and show the results of closed-loop simulations to assess performance and evaluate the trade space of system level stability versus control bandwidth

Optical Budgeting for LUVOIR

Future large astronomical telescopes in space will have architectures that will have complex and demanding requirements to meet the science goals. The Large UV/Optical/IR Surveyor (LUVOIR) mission concept being assessed by the NASA/Goddard Space Flight Center is expected to be 8 to 16 meters in diameter, have a segmented primary mirror, active control, and be diffraction limited at a wavelength of 500 nanometers. The optical stability is expected to be in the picometer range for minutes to hours. Architecture studies to support the NASA Science and Technology Definition teams (STDTs) are underway to evaluate systems performance. A wave front error budget has been developed to help define the technology needs and assess performance. The budget includes both spatial and temporal domain aspects for the active, adaptive and passive elements in the optical design

Thermal Model Performance for the James Webb Space Telescope OTIS Cryo-Vacuum Test

The James Webb Space Telescope (JWST), set to launch in mid-2020, is currently undergoing a series of system-level environmental tests to verify its workmanship and end-to-end functionality. As part of this series, the Optical Telescope Element and Integrated Science Instrument Module (OTIS) Cryo-Vacuum (CV) test, the most complex cryogenic test executed to date by NASA, has recently been completed at the Johnson Space Center's Chamber A facility. The OTIS CV test was intended as a comprehensive test of the integrated instrument and telescope systems to fully understand its optical, structural, and thermal performance within its intended flight environment. Due to its complexity, extensive pre-test planning was required to ensure payload safety and compliance with all limits and constraints. A system-level pre-test thermal model was constructed which fully captured the behavior of the payload, ground support equipment, and surrounding test chamber. This thermal model simulated both the transient cooldown to and warmup from a 20 K flight-like environment, as well as predicted the payload performance at cryo-stable conditions. The current work is an assessment of thermal model pre-test prediction performance against actual payload response during the OTIS CV test. Overall, the thermal model performed exceedingly well at predicting schedule and payload response. Looking in depth, this work examines both the benefits and shortcomings of assumptions made pre-test to simplify model execution when compared against test data. It explores in detail the role of temperature-dependent emissivities during transition to cryogenic temperatures, as well as the impact that model geometry simplifications have on tracking of critical hardware limits and constraints. This work concludes with a list of recommendations to improve the accuracy of thermal modeling for future large cryogenic tests. The insight gained from the OTIS CV test thermal modeling will benefit planning and execution for upcoming cryogenic missions