scholarly journals Imaging-Based Biomarkers: Characterization of Post-Kawasaki Vasculitis in Infants and Hypertension Phenotype in Rat Model

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Roch Listz Maurice ◽  
Nagib Dahdah ◽  
Johanne Tremblay
Keyword(s):  
Mechanical Properties ◽  
Arterial Wall ◽  
Turning Point ◽  
Aortic Wall ◽  
Brown Norway ◽  
Carotid Stiffness ◽  
Old Rats ◽  
The Impact

Background. Investigating the mechanical properties of the arteries is essential in cardiovascular diseases. Recent imaging modalities allow mapping mechanical properties within the arterial wall.Aims. We report the potential ofimaging-based biomarker(ImBioMark) to investigate the effect of aging on the rat. We also present preliminary data with ImBioMark characterizing vascular sequelae of Kawasaki disease (KD) in young humans.Methods. We investigatedin vivothe effect of aging on male Brown Norway (BN) rats' (n=5) carotid stiffness. In a second experiment, the impact of KD on the ascending aorta (AA) was examined in KD children (n=2) aged 13 ± 1.41 years old compared to KD-free children (n=5) aged 13.13 ± 0.18 years old.Results. The stiffness of BN's carotid artery was three times stiffer in the old rats, with a turning point at 40 weeks old (P=0.001). KD had a very significant impact on the AA stiffness with strain estimates of 2.39 ± 0.51% versus 4.24 ± 0.65% in controls (P<0.001).Conclusion. ImBioMark phenotypes hypertension in rat models noninvasivelyin vivowithout resorting to euthanasia. Quantifying aortic wall remodeling is also feasible in humans. Future investigations target human cardiovascular disease.

Characterization of AT2 angiotensin II receptors in rat anterior cerebral arteries

1991 ◽  
Vol 261 (3) ◽  
pp. H667-H670 ◽  
Author(s):  
K. Tsutsumi ◽  
J. M. Saavedra
Keyword(s):  
Angiotensin Ii ◽  
Cerebral Artery ◽  
Arterial Wall ◽  
Anterior Cerebral Artery ◽  
Cerebral Arteries ◽  
Male Rat ◽  
At1 Antagonist ◽  
Maximum Inhibition ◽  
Old Rats

Quantitative autoradiography using the agonist 125I-Sar1-angiotensin II was used to localize and characterize angiotensin II (AT) receptors in the anterior cerebral artery of the male rat. This artery showed a moderately high number of AT receptors, localized throughout the arterial wall. The number of receptors was higher (125 +/- 7 fmol/mg protein) in arteries from young 2-wk-old rats compared with those in adult 8-wk-old rats (43 +/- 2 fmol/mg protein). In the anterior cerebral artery, AT binding was insensitive to displacement with the selective AT1 antagonist DuP 753 but was readily displaced by the selective AT2 antagonist CGP-42112 A (concentration eliciting 50% of maximum inhibition: 6 +/- 1 x 10(-10) M). This indicated that the AT receptors in the cerebral artery were of the AT2 subtype. Our observations suggest that AT may exert its effects on cerebral circulation by stimulation of AT2 receptors and that these receptors may play a role during cerebrovascular development.

The Mechanical Properties of Porcine Coronary Arteries Determined With a Mixed Experimental-Numerical Approach

2008 ◽  
Author(s):  
Arjen van der Horst ◽  
Chantal N. van den Broek ◽  
Marcel C. M. Rutten ◽  
Frans N. van de Vosse
Keyword(s):  
United States ◽  
Mechanical Properties ◽  
Coronary Arteries ◽  
Arterial Wall ◽  
Coronary Circulation ◽  
Mechanical Characterization ◽  
Numerical Approach ◽  
The United States ◽  
Mechanical Factors

Mechanical characterization of the coronary arterial wall is important for several reasons. Mechanical factors play an important role in the development of atherosclerosis [1]. Atherosclerotic coronary arteries may be treated mechanically with interventions like PTCA and stent implantation, 1265000 PTCA procedures were performed in the United States in 2005 [2]. Furthermore, knowledge of the mechanical properties of the arterial wall is important for modeling of the coronary circulation and explaining its hemodynamics.

scholarly journals MR imaging of model drug distribution in simulated vitreous

2015 ◽  
Vol 1 (1) ◽  
pp. 236-239 ◽  
Author(s):  
Sandra Stein ◽  
Christian Simroth-Loch ◽  
Sönke Langner ◽  
Stefan Hadlich ◽  
Oliver Stachs ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ex Vivo ◽  
Drug Distribution ◽  
Injection Technique ◽  
Innovative Therapy ◽  
Age Related ◽  
The Impact

AbstractThe in vitro and in vivo characterization of intravitreal injections plays an important role in developing innovative therapy approaches. Using the established vitreous model (VM) and eye movement system (EyeMoS) the distribution of contrast agents with different molecular weight was studied in vitro. The impact of the simulated age-related vitreal liquefaction (VL) on drug distribution in VM was examined either with injection through the gel phase or through the liquid phase. For comparison the distribution was studied ex vivo in the porcine vitreous. The studies were performed in a magnetic resonance (MR) scanner. As expected, with increasing molecular weight the diffusion velocity and the visual distribution of the injected substances decreased. Similar drug distribution was observed in VM and in porcine eye. VL causes enhanced convective flow and faster distribution in VM. Confirming the importance of the injection technique in progress of VL, injection through gelatinous phase caused faster distribution into peripheral regions of the VM than following injection through liquefied phase. VM and MR scanner in combination present a new approach for the in vitro characterization of drug release and distribution of intravitreal dosage forms.

In vivo characterization of inflammatory biomarkers in swine and the impact of flunixin meglumine administration

2012 ◽  
Vol 148 (3-4) ◽  
pp. 236-242 ◽  
Author(s):  
Sharla M. Peters ◽  
Haile Yancy ◽  
Christine Deaver ◽  
Yolanda L. Jones ◽  
Elizabeth Kenyon ◽  
...  
Keyword(s):  
Inflammatory Biomarkers ◽  
Flunixin Meglumine ◽  
In Vivo Characterization ◽  
The Impact

scholarly journals On the Impact of Vessel Wall Stiffness on Quantitative Flow Dynamics in a Synthetic Model of the Thoracic Aorta

2021 ◽  
Author(s):  
Judith Zimmermann ◽  
Michael Loecher ◽  
Fikunwa Kolawole ◽  
Kathrin Bäumler ◽  
Kyle Gifford ◽  
...  
Keyword(s):  
Thoracic Aorta ◽  
Temporal Resolution ◽  
Aortic Wall ◽  
Predictive Marker ◽  
Flow Dynamics ◽  
4D Flow ◽  
Cross Sectional ◽  
Wall Stiffness ◽  
The Impact

Abstract Aortic wall stiffening is a predictive marker for morbidity in hypertensive patients. Arterial pulse wave velocity (PWV) correlates with the level of stiffness and can be derived using non-invasive 4D-flow magnetic resonance imaging (MRI). The objectives of this study were twofold: to develop subject-specific thoracic aorta models embedded into an MRI-compatible flow circuit operating under controlled physiological conditions; and to evaluate how a range of aortic wall stiffness impacts 4D-flow-based quantification of hemodynamics, particularly PWV. Three aorta models were 3D-printed using a novel photopolymer material at two compliant and one nearly rigid stiffnesses and characterized via tensile testing. Luminal pressure and 4D-flow MRI data were acquired for each model and cross-sectional net flow, peak velocities, and PWV were measured. In addition, the confounding effect of temporal resolution on all metrics was evaluated. Stiffer models resulted in increased systolic pressures (112, 116, and 133 mmHg), variations in velocity patterns, and increased peak velocities, peak flow rate, and PWV (5.8 to 7.3 m/s). Lower temporal resolution (20 ms down to 62.5 ms per image frame) impacted estimates of peak velocity and PWV (7.31 down to 4.77 m/s). Using compliant aorta models is essential to produce realistic flow dynamics and conditions that recapitulated in vivo hemodynamics.

scholarly journals Purification and characterization of a mannose-containing disaccharide obtained from human pregnancy urine. A new immunoregulatory saccharide.

1984 ◽  
Vol 160 (6) ◽  
pp. 1672-1685 ◽  
Author(s):  
A V Muchmore ◽  
J M Decker ◽  
R M Blaese ◽  
B Nilsson
Keyword(s):  
Lymphocyte Culture ◽  
Membrane Receptors ◽  
Cell Wall Polysaccharide ◽  
Human Pregnancy ◽  
Isolation And Characterization ◽  
Pregnancy Urine ◽  
The Impact

Endogenous mammalian lectin-like sugar-binding molecules have been previously described that have immunoregulatory properties. Further, the addition of defined simple saccharides to lymphocyte cultures has been shown to inhibit a variety of in vitro lymphocyte functions, presumably because these sugars are able to compete with the binding of endogenous lectins to critical membrane receptors. In this report, we describe the isolation and characterization of a D-mannose-containing disaccharide in human pregnancy urine that inhibits the proliferative response of human T lymphocytes. The inhibitory disaccharide was purified to homogeneity by sequential steps including affinity chromatography on immobilized concanavalin A and molecular sizing on Sephadex G-75 and then Fractogel 40S columns, with final purification on high-performance thin-layer chromatography. By mass spectrometry of the purified material as its permethylated derivative, the deduced structure of this compound was alpha-D-Manp 1-6-D-Man. To confirm that this disaccharide was in fact immunosuppressive, an identical disaccharide was prepared by sequential digestion of yeast cell wall polysaccharide. The urinary and yeast disaccharides had identical immunosuppressive properties. It has been previously reported that D-mannose is inhibitory for antigen-specific proliferative assays in the range of 10-50 mM. The purified alpha-D-Manp 1-6-D-Man disaccharide was inhibitory at 100-fold-lower concentrations. Further, while D-mannose inhibits T cell proliferation when added at anytime up to 24 h before harvest of a 6-d lymphocyte culture, alpha-D-Manp 1-6-D-Man disaccharide was inhibitory only if added at the initiation of culture and had no inhibitory effect if added just 24 h later. These data support the concept that simple sugar compounds can exhibit marked immunoregulatory activity in vitro. The impact of these molecules on the regulation of immune responses in vivo is unknown, as is their precise mechanism of action, but structural and chemical identification should now permit a detailed analysis of these issues.

EFFECT OF THYROIDECTOMY AND THYROID-STIMULATING HORMONE ON RABBIT AORTA INFLUENCED BY EPINEPHRINE

1962 ◽  
Vol 39 (4) ◽  
pp. 605-614 ◽  
Author(s):  
lb Lorenzen
Keyword(s):  
Arterial Wall ◽  
Aortic Wall ◽  
Rabbit Aorta ◽  
Thyroid Stimulating Hormone ◽  
Simultaneous Injection ◽  
Per Se ◽  
Stimulating Hormone

ABSTRACT The effect of epinephrine on the mucopolysaccharides of the aortic wall in rabbits was studied in thyroidectomized and non-operated animals. In other experiments the effect of thyroid-stimulating hormone (TSH) was investigated after simultaneous injection of epinephrine hydrochloride and after starting the TSH injections one week before the epinephrine injections. Thyroidectomy per se caused no alterations in the aortic content of water, hexosamine, hydroxyproline and in vivo uptake of 35S-sulphate, whereas thyroidectomy inhibited epinephrine-alterations in the aortic wall. This was interpreted as a decreased damage to the arterial wall as a consequence of reduced aortic sensitivity to epinephrine. No effect of TSH on the epinephrine-lesions was demonstrable, probably because of the formation of antihormones.

scholarly journals DISPOSABLE SYSTEM FOR IN-VIVO MECHANICAL CHARACTERIZATION OF SOFT TISSUES BASED ON VOLUME MEASUREMENT

2018 ◽  
Vol 18 (04) ◽  
pp. 1850037 ◽  
Author(s):  
SEYED ALI ELAHI ◽  
NATHANAEL CONNESSON ◽  
YOHAN PAYAN
Keyword(s):  
Mechanical Properties ◽  
Soft Tissues ◽  
Signal To Noise Ratio ◽  
Volume Measurement ◽  
Optical Measurements ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Apex Height

In-vivo characterization of soft tissues is a key step toward biomechanical simulation and planning of intra-operative assisted surgery. To achieve this, aspiration method is a standard technique: tissue is aspirated through a hole while measuring the pressure and associated apex height. An inverse problem is then solved to identify the material mechanical properties. In the literature, the apex height is usually measured using a camera, which induces design difficulties, in particular in regards on the required sterilization process for in-vivo measurements. In this paper, the idea is to replace the apex height optical measurement by the measurement of the aspirated tissue volume. The proposed method enables to reduce the system head to a simple tube: sterilizations becomes easy and the system is disposable after use. The proposed system is thus the simplest, lightest and cheapest one could achieve. It is also to the authors knowledge the first time ever in aspiration method that the aspired volume is the extracted data. As the data signal-to-noise ratio is the main factor impacting any applied inverse method when extracting the mechanical properties, the aim of this work is to assess and compare the experimental signal-to-noise ratio in the raw volume measurements obtained either optically or with the method proposed. Explicit results of inverse methods using volumes as input data are not presented in this paper for concision purpose. The effects on accuracy of various experimental parameters has been investigated and quantified: the volume measurement has proved to present a same order or even better signal-to-noise ratio compared to optical measurements.

Characterization of Mechanical and Thermal Properties of PP/Mineral Composites

2014 ◽  
Vol 1025-1026 ◽  
pp. 241-245 ◽  
Author(s):  
Ľudmila Dulebová ◽  
Emil Spišák ◽  
Branislav Duleba ◽  
František Greškovič ◽  
Tomasz Garbacz
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Twin Screw ◽  
Pp Composites ◽  
Mineral Fillers ◽  
The Impact ◽  
Properties Of Composites

The paper presents the impact of the use of fillers on the mechanical properties of composites with polymeric matrix from polypropylene (PP). Two main types of mineral fillers - talc and calcium carbonate - were used for experiments. PP composites of different percentage filler in matrix PP were compounded with twin-screw extruder and then injection molding. Properties of composites were investigated by tensile test and thermal analysis. Tensile strength was performed to determine and compare the mechanical properties of the unfilled PP and filled PP with various percentages of fillers. Thermal analysis by thermogravimetric was performed on the tested materials - weight loss, glass transition temperature, thermal decomposition, melting temperature.

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