Technical Aspects of the Mouse Aortocaval Fistula

Technical aspects of creating an arteriovenous fistula in the mouse are discussed. Under general anesthesia, an abdominal incision is made, and the aorta and inferior vena cava (IVC) are exposed. The proximal infrarenal aorta and the distal aorta are dissected for clamp placement and needle puncture, respectively. Special attention is paid to avoid dissection between the aorta and the IVC. After clamping the aorta, a 25 G needle is used to puncture both walls of the aorta into the IVC. The surrounding connective tissue is used for hemostatic compression. Successful creation of the AVF will show pulsatile arterial blood flow in the IVC. Further confirmation of successful AVF can be achieved by post-operative Doppler ultrasound.     

An Angiocardiographic Analysis of the Central Circulation in the Air Breathing Teleost Channa argus

The unique anatomy of the double ventral aorta outflow system in the air breathing teleost Channa argus (Ophiocephalus) showing an anterior and posterior ventral aorta is described. The marked trabeculation of the ventricle and bulbus arteriosus and the arrangement of central veins are used as a basis for the hypothesis that Channa may selectively channel the well oxygenated blood draining the air breathing organs via the anterior cardinal vein to the posterior ventral aorta, which forms the systemic arterial circulation. An angiocardiographic technique was used to test this hypothesis, as well as to delineate the functional role of the heart chambers in the cardiac cycle. No reflux of contrast to the sinus venosus during atrial filling and no ventricular filling before atrial contraction were apparent, which makes the atrium the main determinant of the ventricular end-diastolic volume. Ventricular contraction left a small or no residual volume. The ventricular ejectate was initially nearly completely absorbed by the very elastic bulbus arteriosus, acting as a pressure chamber (Windkessel) stabilizing and prolonging ventral aortic blood flow. Contrast medium was not selectively passed from the anterior cardinal vein to the posterior ventral aorta. However, the diameter of this vessel and its density of contrast were greater than in the anterior aorta, suggesting a preference for a greater blood flow from the air breathing organ through the heart to the posterior aorta.     

Magnetic resonance tomography in the diagnosis of aneurysm and coarctation of the thoracic aorta]

MR-tomography (MRT) was performed in 25 patients with aneurysms and in 11 with coarctation of the thoracic aorta. For investigations a device with a resistive magnet (the force of a field--0.23 T) was used simultaneously with ECG. MRT revealed all cases of aortic dissection (10 patients) and one case with a false-positive result. Oblique sections in the direction of the thoracic aorta were used to assess the state of the aortic arch branches. Comparison of MRT and x-ray computerized tomography has shown that the diagnostic value of both methods was almost equal, however MRT was a safer method and easier to use. MRT was shown to be a method of choice for diagnosis of aneurysms and coarctations of the thoracic aorta but cannot be a substitution for aortography.     

A study of aneurysmal lesions of the aorta using magnetic resonance tomography

Altogether 23 patients with aneurysmal aortic lesions of various sites were investigated using MR-tomography. Sagittal and axial projections were used for visualization of the thoracic aorta, frontal and axial ones--for visualization of the abdominal aorta. As compared to radionuclide and x-ray methods of investigation, MR-tomography was characterized by a high informative value in the detection of aneurysmal lesions. Despite a limited number of patients the authors managed to diagnose aortic stratification which could be well visualized in the abdominal aorta.     

Measuring,reversing, and modeling the mechanical changes due to the absence of Fibulin-4 in mouse arteries

Mice with a smooth muscle cell (SMC)-specific deletion of Fibulin-4 (SMKO) show decreased expression of SMC contractile genes, decreased circumferential compliance, and develop aneurysms in the ascending aorta. Neonatal administration of drugs that inhibit the angiotensin II pathway encourages the expression of contractile genes and prevents aneurysm development, but does not increase compliance in SMKO aorta. We hypothesized that multidimensional mechanical changes in the aorta and/or other elastic arteries may contribute to aneurysm pathophysiology. We found that the SMKO ascending aorta and carotid artery showed mechanical changes in the axial direction. These changes were not reversed by angiotensin II inhibitors, hence reversing the axial changes is not required for aneurysm prevention. Mechanical changes in the circumferential direction were specific to the ascending aorta; therefore, mechanical changes in the carotid do not contribute to aortic aneurysm development. We also hypothesized that a published model of postnatal aortic growth and remodeling could be used to investigate mechanisms behind the changes in SMKO aorta and aneurysm development over time. Dimensions and mechanical behavior of adult SMKO aorta were reproduced by the model after modifying the initial component material constants and the aortic dilation with each postnatal time step. The model links biological observations to specific mechanical responses in aneurysm development and treatment.     

Isolation and Excision of Murine Aorta; A Versatile Technique in the Study of Cardiovascular Disease

Cardiovascular disease is a broad term describing disease of the heart and/or blood vessels. The main blood vessel supplying the body with oxygenated blood is the aorta. The aorta may become affected in diseases such as atherosclerosis and aneurysm. Researchers investigating these diseases would benefit from direct observation of the aorta to characterize disease progression as well as to evaluate efficacy of potential therapeutics. The goal of this protocol is to describe proper isolation and excision of the aorta to aid investigators researching cardiovascular disease. Isolation and excision of the aorta allows investigators to look at gross morphometric changes as wells as allowing them to preserve and stain the tissue to look at histologic changes if desired. The aorta may be used for molecular studies to evaluate protein and gene expression to discover targets of interest and mechanisms of action. This technique is superior to imaging modalities as they have inherent limitations in technology and cost. Additionally, primary isolated cells from a freshly isolated and excised aorta can allowing researchers to perform further in situ and in vitro assays. The isolation and excision of the aorta has the limitation of having to sacrifice the animal however, in this case the benefits outweigh the harm as it is the most versatile technique in the study of aortic disease.     

Changes in expression of angiotensin receptor subtypes in the rat aorta during development

Quantitative autoradiography was used to characterize angiotensin AT1 and AT2 receptors, in the rat aorta at three developmental ages; embryonic day 18 (E18), and postnatal weeks 2 and 8. The expression of angiotensin receptors was higher in the aorta of E18 and 2-week-old rat. A major proportion of the angiotensin receptors expressed in the aorta at these two ages was AT2 (84 and 81% respectively). Conversely, in the aorta of 8-week-old rats, AT1 was the predominant angiotensin receptor subtype (71%). In 8-week-old rats, the AT2 subtype was also present (28%). In pre- and postnatal rats, [125I]Sar1-angiotensin II binding to AT1 receptors was sensitive to GTP gamma S whereas binding to AT2 receptors was not. AT2 receptors may serve an important role during stages of rapid growth of the aorta, and also have a significant function in the adult vasculature.     

A purification procedure for the isolation of homogeneous preparations of bovine aorta amine oxidase and a study of its lysyl oxidase activity.

It has been reported that bovine aorta amine oxidase oxidizes lysine residues in tropoelastin to allysine (Rucker, R.B. and O'Dell, B.L. (1971) Biochim. Biophys. Acta 235, 32-43). Pure bovine aorta amine oxidase was isolate by DEAE-cellulose, hydroxylapatite, Bio-Gel A-1.5 m and concanavalin A-Sepharose 4B chromatography. Enzymatic, chromatographic and immunochemical tests disclosed that pure bovine aorta amine oxidase was not a lysyl oxidase capable of oxidizing the lysine residues of tropoelastin to allysine; The bovine aorta amine oxidase preparation used by Rucker and O'Dell appears to have been contaminated with lysyl oxidase which is the emzyme that oxidizes some of the lysine residues in tropoelastin and tropocollagen to allysine.     

Capacities of computed tomographic angiography in the diagnosis and estimation of the site, pattern, and degree of vascular bed lesion in nonspecific aortoarteritis

Nonspecific aortoarteritis (NAA) is a chronic inflammatory disease that affects the aorta and its branches. The clinical manifestations of this disease are of a great variety and depend on the site of a lesion and the stage of the disease. A wide range of highly informative noninvasive imaging techniques, such as duplex scanning (DS), magnetic resonance imaging (MRI), and computed tomography (CT) of the aorta and its branches, are used to make a more accurate diagnosis and to determine the site and extent of a vascular bed lesion. The given clinical example suggests that CT angiography of the aorta and its branches is a high-precision technique in determining the site of vascular bed lesion in patients with NAA and the pattern and extent of arterial involvement and that it may be used for both the diagnosis of the disease at its developmental stages and the monitoring of the vessels during pathogenetic therapy.     

Sequence homologies between p36, the substrate of pp60src tyrosine kinase and a 67 kDa protein isolated from bovine aorta

A 67 kDa actin-binding protein was isolated from bovine aorta. Partial amino acid sequence determination of two large thermolysin peptides were used to compare 67 kDa bovine aorta protein and p36 the substrate of pp60src tyrosine kinase. Sequence analysis shows that 67 kDa bovine aorta protein shares common domains with p36 and possesses the consensus aminoacid sequences of mammalian Ca2+-dependent membrane-binding protein and p36/gelsolin.     

Unsteady and three-dimensional simulation of blood flow in the human aortic arch

A three-dimensional and pulsatile blood flow in a human aortic arch and its three major branches has been studied numerically for a peak Reynolds number of 2500 and a frequency (or Womersley) parameter of 10. The simulation geometry was derived from the three-dimensional reconstruction of a series of two-dimensional slices obtained in vivo using CAT scan imaging on a human aorta. The numerical simulations were obtained using a projection method, and a finite-volume formulation of the Navier-Stokes equations was used on a system of overset grids. Our results demonstrate that the primary flow velocity is skewed towards the inner aortic wall in the ascending aorta, but this skewness shifts to the outer wall in the descending thoracic aorta. Within the arch branches, the flow velocities were skewed to the distal walls with flow reversal along the proximal walls. Extensive secondary flow motion was observed in the aorta, and the structure of these secondary flows was influenced considerably by the presence of the branches. Within the aorta, wall shear stresses were highly dynamic, but were generally high along the outer wall in the vicinity of the branches and low along the inner wall, particularly in the descending thoracic aorta. Within the branches, the shear stresses were considerably higher along the distal walls than along the proximal walls. Wall pressure was low along the inner aortic wall and high around the branches and along the outer wall in the ascending thoracic aorta. Comparison of our numerical results with the localization of early atherosclerotic lesions broadly suggests preferential development of these lesions in regions of extrema (either maxima or minima) in wall shear stress and pressure.     

Identification of smooth muscle-derived foam cells in the atherosclerotic plaque of human aorta with monoclonal antibody IIG10

We have developed a monoclonal antibody that specifically interacts with a surface antigen of human fibroblasts and smooth muscle cells. The antibody (antibody IIG10) recognizes a polypeptide of molecular mass 330,000, revealed by immunoblotting in fibroblast and smooth muscle cell extract, but not in vascular endothelial cells, peritoneal macrophages, peripheral blood lymphocytes nor hepatocytes. In tissue sections the antibody stained smooth muscle cells of myometrium, aorta and smaller blood vessels, and fibroblasts of connective tissue. Specificity of the antibody was further confirmed by double staining of aorta sections. Antibody IIG10 was used to identify smooth muscle-derived foam cells in the atherosclerotic plaque of human aorta.     

The effects of tapering and artery wall stiffness on treatments for Coarctation of the Aorta

Coarctation of the Aorta is a congenital narrowing of the aorta. Two commonly used treatments are resection and end-to-end anastomosis, and stent placements. We simulate blood flow through one-dimensional models of aortas. Different artery stiffnesses, due to treatments, are included in our model, and used to compare blood flow properties in the treated aortas. We expand our previously published model to include the natural tapering of aortas. We look at change in aorta wall radius, blood pressure and blood flow velocity, and find that, of the two treatments, the resection and end-to-end anastomosis treatment more closely matches healthy aortas.     

Radioautographic studies of the initial site of formation of protein-bound iodine in the rat thyroid gland

1. Predominantly cellular labelling was observed in radioautographs of rat thyroid glands fixed by perfusion from the aorta at intervals between 5 and 55s after [(125)I]iodide administration via the aorta. 2. When perfusion was delayed for 2min, or if immersion fixation was used, the labelling was predominantly over the peripheral portion of the follicular lumen, in agreement with the observations of other investigators. 3. The findings support the concept that the initial site of binding of iodine to protein is intracellular, but the nature of this protein has not been established.     

大鼠降主动脉雌激素受体的免疫组织化学研究

冰冻切片微波修复后,用ER单克隆抗体免疫组织化学SP法及图像分析方法,观察雌激素受体（ER）在雌性与雄性大鼠降主动脉壁的分布,结果显示,ER阳性反应存在于血管壁的内皮细胞与平滑肌细胞中,阳性反应强度无性别差异。无段间差异（降主动脉胸段与腹段）,血管周围的脂肪组织也可见大量呈阳性反应的细胞,结果表明,降主动脉壁的内皮细胞,血管平滑肌细胞中存在ER。降主动脉可能是雌激素的靶器官。     

运动训练对大鼠主动脉应力和NF-κB及c-fos表达的影响

目的：探讨不同强度运动训练对大鼠主动脉应力和NF-κB及c-fos表达的影响。方法：采用跑台训练方式,建立大鼠有氧运动和疲劳运动模型,运用免疫组织化学SABC法研究不同强度运动训练对大鼠主动脉VEC和VSMC中NF-κB及c-fos表达的影响。结果：胸主动脉血压的变化与对照组比较,有氧训练和疲劳训练均显著性升高（P〈0．05）,但有氧训练与疲劳训练之间差异不显著。与对照组比较,有氧训练大鼠VEC和VSMC中NF-κB和c-fos均显著性下调表达,胸主动脉张开角显著性升高（P〈0．05）,疲劳训练大鼠VEC和VSMC中NF-κB和c-fos均显著性上调表达（P〈0．05）。与有氧运动组比较,疲劳运动大鼠VEC和VSMC中NF-κB和c-fos表达与胸主动脉张开角升高均具有显著性差异（P〈0．05）。表明不同强度运动大鼠主动脉VEC中NF-κB和c-fos表达变化趋势不同,疲劳训练组表达的增加趋势更显著。结论：运动可引起大鼠主动脉VEC和VSMC NF-κB及c-fos表达的变化,且与运动强度关系密切。有氧训练引起的慢性剪切应力变化可使主动脉VEC和VSMC NF-κB加及c-fos显著性下调表达,与VEC和VSMC维持血管功能的稳态有关;疲劳训练可导致壁面摩擦剪切力、周向应力增加,过度的剪切力作用可引起主动脉VEC和VSMC NF-κB及c-fos显著性上调表达,血管张开角显著增加,血管发生非均匀生长,引起血管结构与功能的重塑。     

Effect of exposure to diabetic and fasted plasma on glucose oxidation in rat aorta

Glucose metabolism is depressed in aortic intima-media of fasted and diabetic rats. The aim of this study was to elucidate the influence of diabetic and fasted plasma on glucose oxidation in rat aorta. Male Sprague-Dawley rats weighing about 200 g were used. Diabetes was induced by streptozotocin (65 mg/kg) and the rats were used after a diabetes duration of two weeks. Fasted rats were used after food deprivation for 3 days. Aortic intima-media was preincubated in plasma for 120 or 240 min. During a further incubation for 2 hours in Krebs-Henseleit bicarbonate buffer the oxidation of 14C-glucose to 14CO2 was measured. Preincubation of normal aorta in diabetic or fasted rat plasma and diabetic human plasma significantly depressed the subsequently determined glucose oxidation in comparison to aorta preincubated in normal plasma. Preincubation of aorta from diabetic or fasted rats in normal rat plasma enhanced the glucose oxidation compared with the glucose oxidation in aorta of diabetic or fasted rats after preincubation in the corresponding plasma. These results suggest that diabetic and fasted plasma contains factor(s) which in vitro depress glucose oxidation in vascular smooth muscle and, thus, may be of importance for the lowered glucose oxidation found in vascular smooth muscle preparations obtained from diabetic or fasted animals.     

Blood pressure regulates the activity and function of the Na-K-2Cl cotransporter in vascular smooth muscle

The Na-K-2Cl cotransporter (NKCC1) is one of several transporters that have been linked to hypertension, and its inhibition reduces vascular smooth muscle tone and blood pressure. NKCC1 in the rat aorta is stimulated by vasoconstrictors and inhibited by nitrovasodilators, and this is linked to the contractile state of the smooth muscle. To determine whether blood pressure also regulates NKCC1, we examined the acute effect of hypertension on NKCC1 in rats after aortic coarctation. In the hypertensive aorta (28-mmHg rise in mean blood pressure), an increase in NKCC1 activity (measured as bumetanide-sensitive (86)Rb efflux) was apparent by 16 h and reached a plateau of 62% greater than control at 48 h. In contrast, there was a slight decrease in NKCC1 activity in the hypotensive aorta (21% decrease in mean blood pressure). Measurement of NKCC1 mRNA by real-time PCR revealed a fivefold increase in the hypertensive aorta compared with the hypotensive aorta or sham aorta. The inhibition by bumetanide of isometric force response to phenylephrine was significantly greater in the hypertensive aorta than in the control aorta or hypotensive aorta. We conclude that NKCC1 in rat aortic smooth muscle is regulated by blood pressure, most likely through changes in transporter abundance. This upregulation of NKCC1 is associated with a greater contribution to force generation in the hypertensive aorta. This is the first demonstration that NKCC1 in vascular smooth muscle is regulated by blood pressure and indicates that this transporter is important in the acute response of vascular smooth muscle to hypertension.     

Insertion of the Impella 5.0 left ventricular assist device via right anterior mini-thoracotomy: a novel practical approach

The Impella 5.0 microaxial pump is a miniaturized left ventricular assist device commonly used for circulatory support in acute cardiogenic shock. The catheter-based pump is designed to be inserted either into a peripheral artery or directly into the ascending aorta. We report the first case in which the Impella 5.0 device was placed directly into the ascending aorta via a small right anterior thoracotomy in a patient following acute myocardial infarction complicated by cardiogenic shock.     

Wave intensity in the ascending aorta: effects of arterial occlusion

We examine the effects of arterial occlusion on the pressure, velocity and the reflected waves in the ascending aorta using wave intensity analysis. In 11 anaesthetised, open-chested dogs, snares were used to produce total arterial occlusion at 4 sites: the upper descending aorta at the level of the aortic valve (thoracic); the lower thoracic aorta at the level of the diaphragm (diaphragm); the abdominal aorta between the renal arteries (abdominal) and the left iliac artery, 2 cm downstream from the aorta iliac bifurcation (iliac). Pressure and flow in the ascending aorta were measured, and data were collected before and during the occlusion. During thoracic and diaphragm occlusions a significant increase in mean aortic pressure (46% and 23%) and in wave speed (25% and 10%) was observed, while mean flow rate decreased significantly (23% and 17%). Also, the reflected compression wave arrived significantly earlier (45% and 15%) and its peak intensity was significantly greater (257% and 125%), all compared with control. Aortic occlusion distal to the renal arteries, however, caused an indiscernible change in the pressure and velocity waveforms, and in the intensities and timing of the waves in the forward and backward directions. The measured pressure and velocity waveforms are the result of the interaction between the heart and the arterial system. The separated pressure, velocity and wave intensity are required to provide information about arterial hemodynamic such as the timing and magnitude of the forward and backward waves. The net wave intensity is simpler to calculate but provides information only about the predominant direction of the waves and can be misleading when forward and backward waves of comparable magnitudes are present simultaneously.