Reaction kinetics analysis to estimate in vivo decay rate of EPR signals of a nitroxide radical in the brain and the inferior vena cava of rats

2003 ◽  
Vol 25 (2) ◽  
pp. 217-225 ◽  
Author(s):  
H. Yokoyama ◽  
M. Tada ◽  
O. Itoh ◽  
K. Fukui
Keyword(s):  
Inferior Vena Cava ◽  
Decay Rate ◽  
Reaction Kinetics ◽  
Inferior Vena ◽  
Vena Cava ◽  
Nitroxide Radical ◽  
Kinetics Analysis ◽  
The Brain

scholarly journals 5-HT causes splanchnic venodilation

2017 ◽  
Vol 313 (3) ◽  
pp. H676-H686 ◽  
Author(s):  
Bridget M. Seitz ◽  
Hakan S. Orer ◽  
Teresa Krieger-Burke ◽  
Emma S. Darios ◽  
Janice M. Thompson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Inferior Vena Cava ◽  
Portal Vein ◽  
Superior Mesenteric Vein ◽  
Inferior Vena ◽  
Vena Cava ◽  
Receptor Protein ◽  
Mesenteric Vein

Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implanted radiotelemetry transmitters underwent repeated ultrasound imaging of abdominal vessels. After baseline imaging, minipumps containing vehicle (saline) or 5-HT (25 μg·kg−1·min−1) were implanted. Twenty-four hours later, venous diameters were increased in rats with 5-HT-infusion (percent increase from baseline: superior mesenteric vein, 17.5 ± 1.9; portal vein, 17.7 ± 1.8; and abdominal inferior vena cava, 46.9 ± 8.0) while arterial pressure was decreased (~13 mmHg). Measures returned to baseline after infusion termination. In a separate group of animals, treatment with SB-269970 (3 mg/kg iv) prevented the splanchnic venodilation and fall in blood pressure during 24 h of 5-HT infusion. Thus, 5-HT causes 5-HT7 receptor-dependent splanchnic venous dilation associated with a fall in blood pressure. NEW & NOTEWORTHY This research is noteworthy because it combines and links, through the 5-HT7 receptor, an in vitro observation (venorelaxation) with in vivo events (venodilation and fall in blood pressure). This supports the idea that splanchnic venodilation plays a role in blood pressure regulation.

scholarly journals In vivo magnetic particle imaging: angiography of inferior vena cava and aorta in rats using newly developed multicore particles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Azadeh Mohtashamdolatshahi ◽  
Harald Kratz ◽  
Olaf Kosch ◽  
Ralf Hauptmann ◽  
Nicola Stolzenburg ◽  
...  
Keyword(s):  
Image Quality ◽  
Inferior Vena Cava ◽  
Temporal Resolution ◽  
Magnetic Particle ◽  
Inferior Vena ◽  
Vena Cava ◽  
High Temporal Resolution ◽  
Magnetic Particle Imaging ◽  
Particle Imaging

Abstract Magnetic Particle Imaging (MPI) is a new imaging modality, which maps the distribution of magnetic nanoparticles (MNP) in 3D with high temporal resolution. It thus may be suited for cardiovascular imaging. Its sensitivity and spatial resolution critically depend on the magnetic properties of MNP. Therefore, we used novel multicore nanoparticles (MCP 3) for in-vivo MPI in rats and analyzed dose requirements, sensitivity and detail resolution. 8 rats were examined using a preclinical MPI scanner (Bruker Biospin GmbH, Germany) equipped with a separate receive coil. MCP 3 and Resovist were administered intravenously (i.v.) into the rats’ tail veins at doses of 0.1, 0.05 and 0.025 mmol Fe/kg followed by serial MPI acquisition with a temporal resolution of 46 volumes per second. Based on a qualitative visual scoring system MCP 3–MPI images showed a significantly (P ≤ 0.05) higher image quality than Resovist-MPI images. Morphological features such as vessel lumen diameters (DL) of the inferior vena cava (IVC) and abdominal aorta (AA) could be assessed along a 2-cm segment in mesenteric area only after administration of MCP 3 at dosages of 0.1, 0.05 mmol Fe/kg. The mean DL ± SD estimated was 2.7 ± 0.6 mm for IVC and 2.4 ± 0.7 mm for AA. Evaluation of DL of the IVC and AA was not possible in Resovist-MPI images. Our results show, that MCP 3 provide better image quality at a lower dosage than Resovist. MCP 3-MPI with a clinically acceptable dose of 0.05 mmol Fe/kg increased the visibility of vessel lumens compared to Resovist-based MPI towards possible detection of vascular abnormalities such as stenosis or aneurysms, in vivo.

Compartment analysis of the radiorenogram and distribution of Hippuran I131 in dogs

1963 ◽  
Vol 204 (6) ◽  
pp. 1059-1064 ◽  
Author(s):  
M. Donald Blaufox ◽  
Alan L. Orvis ◽  
Charles A. Owen
Keyword(s):  
Inferior Vena Cava ◽  
Plasma Volume ◽  
Biliary Excretion ◽  
Inferior Vena ◽  
Vena Cava ◽  
Plasma Samples ◽  
Compartment Analysis ◽  
Arterial Plasma ◽  
Blood Radioactivity

Radioiodinated Hippuran was injected into the inferior vena cava of three unilaterally and three bilaterally nephrectomized dogs. Radioactivity was recorded over the precordium and remaining kidney in the former group and the precordium and renal fossa in the latter. The disappearance of I131 from plasma was analyzed and interpreted by two-compartment and three-compartment systems. Theoretical curves for cardiac and renal areas (constructed from analysis of arterial plasma samples) agreed well with curves from in vivo counting. Analyzed by either model, the first compartment exceeded the plasma volume severalfold, part seeming to be in the kidney. Extravascular compartments, impossible to sample, were not identified. About 15% of whole-blood radioactivity was in erythrocytes. Biliary excretion of Hippuran I131 was insignificant unless nephrectomy was bilateral; then up to 60% was excreted in the bile in 24 hr. Protein binding could not be demonstrated. Radiorenograms converted to fairly accurate rate constants may prove more useful than descriptive methods currently employed. Understanding the distribution and excretion of Hippuran appears helpful to accurate interpretation of the radiorenogram.

Abstract 233: Quantification of Histological and Biomechanical Properties of Tissue-Engineered Vascular Graft in Inferior Vena Cava

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Yuji Naito ◽  
Yong-Ung Lee ◽  
Tai Yi ◽  
Spencer N Church ◽  
Daniel Solomon ◽  
...  
Keyword(s):  
Gene Expression ◽  
Inferior Vena Cava ◽  
Vascular Graft ◽  
Inferior Vena ◽  
Vena Cava ◽  
Biomechanical Properties ◽  
Type I ◽  
Ecm Remodeling ◽  
Total Collagen

Background: We developed the first tissue engineered vascular graft (TEVG) for use in congenital heart surgery and confirmed its significant potential via an initial clinical trial (Shinoka et al., JTCVS 2005). The primary complication of TEVG at medium term was stenosis attributed to suboptimal neovessel remodeling, which necessitated an investigation of the mechanics and mechanobiology to predict diverse aspects of the neovessel formation. Here we present the novel tools to investigate the evolving biomechanical properties of TEVG in a mouse inferior vena cava (IVC) replacement model. Hypothesis: The biomechanical properties of a TEVG evolve nonlinearly in time from a construct-dominated stiffness to a neovessel dominated stiffness. Novel biaxial biomechanical tests are required to quantify such changes rigorously. Method: Thirty-six CB17 SCID/beige mice were implanted with TEVG (PGA + P[CL/LA]) as IVC interposition graft. Twelve tissue engineered neovessels were harvested at 2, 6, and 12 weeks after implantation. Neovessels were characterized biomechanically using a custom, computer-controlled biaxial testing device, and compared with native veins. Extracellular matrix (ECM) remodeling of the neovessel was characterized histologically, biochemically, and molecular biologically. Result: The biaxial data revealed an improved compliance of the neovessel over time. Similarly, the axial stretch response of the TEVG became more like the native vein at 12 weeks. This response was quantified as a ratio of neo-vessel to native vein and improved to reach 52% at 12 weeks from 11% at 2 weeks. Scaffold mass in vivo, estimated by remaining scaffold on histology, showed a significant decline at 6 and 12 weeks. Gene expression of both type I and III collagen peaked at 2 weeks, and total collagen mass quantified by a Sircol™ assay revealed that total collagen peaked at 2 weeks but decreased gradually to the level of native vein. Gene expression of both tropoelastin and fibrillin-1 peaked at 2 weeks, whereas elastin mass quantified by Fastin™ assay showed a delayed peak level of elastin at 6 weeks. Gene expression of MMP-2 and 9 peaked at 6 and 2 weeks, respectively, implicating robust ECM remodeling at early time points. Conclusion: Our novel histo-mechanical approach is the first to show that neovessel formation is a dynamic process characterized by progressive degradation of the scaffold and increased ECM remodeling, which yields biomechanical properties of the TEVG similar to native vessel within 12 weeks in vivo.

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