Visualization of Complex Flow Patterns in Angiotensin II-Induced Dissecting Murine Abdominal Aortic Aneurysms with High Frequency Ultrasound

Abdominal aortic aneurysm (AAA) rupture is a common cause of mortality in the United States. Current treatments are only employed once the risk of rupture outweighs the risks associated with surgery. Murine models have been developed to characterize AAA pathogenesis in the hope that new treatments will be developed. For this study, angiotensin II (AngII) was infused subcutaneously into apolipoprotein E-deficient (ApoE-/-) mice using an osmotic mini-pump over 28 days. ApoE-/- mice (16-week-old, 3 females, 2 males) were imaged using a VisualSonics Vevo 2100 high frequency ultrasound before pump implantation and 3, 7, 14, 21, and 27 days following implantation. Images were acquired in the transverse and longitudinal planes from the suprarenal region of the aorta. Blood pressure measurements were taken using a tail-cuff system (CODA, Kent Scientific). Three mice (1 female, 2 male) developed aneurysms within the first 14 days of infusion. Pre-study abdominal aortas had a diastolic diameter of 0.84±0.09 mm and a systolic diameter of 0.96±0.08 mm. By day 21, AAAs had a diastolic diameter of 1.51±0.59 mm and a systolic diameter of 1.56±0.59 mm. Initially, mice had a systolic blood pressure of 111.94±6.53 mmHg and a diastolic pressure of 82.38±5.13 mmHg. These pressures steadily elevated but eventually began to plateau. By day 27, systolic pressure had risen to 154.92±11.43 mmHg and diastolic pressure to 115.77±10.25 mmHg. Color Doppler images revealed complex, recirculating flow within the aneurysms, a phenomenon which could affect vessel remodeling. In conclusion, this study utilized in vivo sonographic methods to characterize AAA development

In Vivo Flow Measurements of Murine Renal Arteries and Veins with High Frequency Ultrasound

The number of glomeruli in the kidneys has been shown to have an effect on the decline in renal function over time (Brenner, Garcia, Anderson 1988). Furthermore, flow in the renal arteries and veins may depend on the number of glomeruli in the kidney. Consistent in vivo measurements of volumetric flow in the renal arteries and veins are difficult to obtain. Thus, the purpose of this study was to develop non-invasive imaging techniques capable of estimating arterial and venous flow to kidneys. A high-frequency small animal ultrasound system was chosen based upon its excellent spatial and temporal resolution when imaging mice (Vevo 2100, VisualSonics, Inc.). Velocity profiles of the renal arteries and veins in C57BL/6 male mice (n=4) were measured. Motion, color Doppler, and pulsed wave Doppler data were acquired and used to determine renal diameter, maximum velocity, mean velocity, and volumetric flow for both kidneys. For the renal artery the average volumetric flow was 33.31±7.16 mm3/s and for the renal vein it was 30.23±4.58 mm3/s. The next step will be imaging the same animals multiple times to ensure that these measurements are consistent over prolonged periods of time. Then data will be collected from different breeds of mice to conclude whether or not differences in glomeruli number affect renal flow. Measurement of volumetric flow in the renal arteries and veins can lead to important insights into how the glomeruli density in kidneys relates to renal flow and function

Constraint degree in revision total knee replacement: a registry study on 1432 patients

Purpose: Total knee replacement (TKR) failure represents a hard challenge for knee surgeons. TKR failure can be managed in revision with different constraint, related with soft and bone knee damages. The choice of the right constraint for every failure cause represents a not summarized entity. The purpose of this study is identifying distribution of different constraints in revision TKR (rTKR) for failure cause and the overall survival. Methods: A registry study based on the Emilia Romagna Register of the Orthopaedic Prosthetic Implants (called RIPO) was performed with a selection of 1432 implants, in the period between 2000 and 2019. Selection implants including primary surgery constraint, failure cause and constraint revision for every patient, and divided for constraint degrees used during procedures (Cruciate Retaining-CR, Posterior Stabilized-PS, Condylar Constrained Knee-CCK, Hinged). Results: The most common cause of primary TKR failure was aseptic loosening (51,45%), followed by septic loosening (29,12%). Each type of failure was managed with different constraint, the most used was CCK in the most of failure causes, such as to manage aseptic and septic loosening in CR and PS failure. Overall survival of TKA revisions has been calculated at 5 and 10 years for each constraint, with a range of 75.1-90.0% at 5 years and 75.1-87.5% at 10 years. Conclusion: Constraint degree in rTKR is typically higher than primary, CCK is the most used constraint in revision surgery with an overall survival of 87.5% at 10 years

Total knee replacements using rotating hinge implants in polio patients: clinical and functional outcomes

Little evidences are available in the literature concerning the outcomes of total knee replacement (TKR) in poliomyelitis patients with severe knee deformities or degeneration. Encouraging results have been reported concerning the use of constrained implants, i.e., rotating hinge knee prosthesis (RHK), compared to less constrained ones. The purpose of this paper is to report our experience with rotating hinge total knee replacement, using only RHK prosthesis, to determine functional results, complications, and survival of TKR in poliomyelitis patients. We performed a retrospective chart review of 14 patients with a history of knee osteoarthritis following poliomyelitis that underwent primary TKR, for a total of 15 surgical procedure (one bilateral case). Preoperative and postoperative clinical measurements have been conducted for all patients using the Knee Society Score (KSS). Hip-knee angle, recurvatum knee angle, and Insall-Salvati index were evaluated with full weight-bearing panoramic view X-ray preoperatively and postoperatively. The 2-year postoperative clinical KSS significantly improved from the preoperative scores. The average clinical KSS improved from 32,9 (range 3-48) preoperatively to 77,4 (range 60-88) postoperatively (P value < 0.005). The average functional KSS improved from 32,5 (range 10-60) preoperatively to 59,4 (range 30-95) postoperatively (P value < 0.005). TKR is a successful treatment in improving knee function and patient's quality of life. Using constrained implants, especially rotating hinge implants in polio patients with a quadriceps muscle weakness, could be a good alternative to maintain a physiological kinematics and reducing the revision rate due to knee instability

Internal solitary waves in the Coastal Mixing and Optics 1996 experiment : multimodal structure and resuspension

Observations of internal solitary waves (ISWs) and of their role in sediment resuspension during the Coastal Mixing and Optics 1996 (CMO 96) experiment are reported. The largest resuspension events observed in the experiment can be related to retarded flow under the wave footprint. Two distinctly different periods of resuspension events could be distinguished based on the prevailing atmospheric conditions: a calm period, which we consider characteristic of nominal conditions, and an energetic period, during which two major storms occurred. ISWs arrived at the mooring site from a variety of sources, though a common intermodal dynamics seemed to occur repeatedly. Both mode 1 and mode 2 ISWs have been observed. The present analysis of the month-long portion of the CMO 96 data set constitutes the first reported observations, insofar as we are aware, of mode 2 waves on the continental shelf. Both mode 1 and mode 2 ISWs were found to stimulate resuspension. The mode 2 waves seem to be generated locally by resonant or topographic interactions with mode 1 ISWs. Internal wave fields of the type described here are expected to exist in a variety of other shallow seas as well

Giant Monopole Resonance in Transitional and Deformed-Nuclei

Journals published by the American Physical Society can be found at http://publish.aps.org

On the Nature of the Frontal Zone of the Choctawhatchee Bay Plume in the Gulf of Mexico

River plumes often feature turbulent processes in the frontal zone and interfacial region at base of the plume, which ultimately impact spreading and mixing rates with the ambient coastal ocean. The degree to which these processes govern overall plume mixing is yet to be quantified with microstructure observations. A field campaign was conducted in a river plume in the northeast Gulf of Mexico in December 2013, in order to assess mixing processes that could potentially impact transport and dispersion of surface material near coastal regions. Current velocity, density, and Turbulent Kinetic Energy Values, ε, were obtained using an Acoustic Doppler Current Profiler (ADCP), a Conductivity Temperature Depth (CTD) profiler, a Vertical Microstructure Profiler (VMP), and two Acoustic Doppler Velocimeters (ADVs). The frontal region contained ε values on the order of 10−5 m2 s−3, which were markedly larger than in the ambient water beneath (O 10−9 m2s−3). An energetic wake of moderate ε values (O 10−6 m2 s−3) was observed trailing the frontal edge. The interfacial region of an interior section of the plume featured opposing horizontal velocities and a ε value on the order of 10−6 m2 s−3. A simplified mixing budget was used under significant assumptions to compare contributions from wind, tides, and frontal regions of the plume. The results from this order of magnitude analysis indicated that frontal processes (59%) dominated in overall mixing. This emphasizes the importance of adequate parameterization of river plume frontal processes in coastal predictive models

Secondary circulation associated with a shelfbreak front

Evidence for secondary circulation associated with a shelfbreak front is obtained from a high‐resolution, cross‐shelf section of hydrographic, optical and velocity fields. Convergence in the bottom boundary layer on the inshore side of the front and subsequent upwelling into the interior is evident by a mid‐water region of suspended bottom material emanating from the foot of the front and extending to within 35 m of the surface, 80 m above bottom. Downwelling on the offshore side of the front in the upper water column is inferred from a 20‐m downward bend of the subsurface phytoplankton layer. These observations are in agreement with recent model predictions for secondary circulation near an idealized shelfbreak front. Convergence in measured cross‐shelf velocity at the foot of the front is consistent with upwelling of bottom material detected there. An estimate of 9±2 m day⁻¹ of upwelling on the inshore side of the shelfbreak front is obtained, implying a transit time from the bottom to the surface of 10–16 days