Differences In Wall Thickness Research Articles

Anatomical characteristics and wood properties of Melaleuca leucadendron naturally growing in secondary forest in Indonesia

SummaryDynamic Young’s modulus of elasticity (DMOE) of logs, anatomical characteristics and wood properties were determined for naturally regenerated Melaleuca leucadendron trees grown in secondary forest in an area of peat swamp, South Kalimantan, Indonesia. The mean value of DMOE of logs was 7.99 GPa. Mean basic density (BD) and compressive strength (CS) ranged from 0.43 to 0.60 g cm−3 and 34.5 to 52.4 MPa, respectively. Vessel diameter and wood fibre length increased along the first 2 cm of the radius from the pith and then showed almost constant values between that point and the bark, suggesting that xylem maturation starts at about 2 cm from the pith. The wall thickness of wood fibres gradually increased from pith to bark, and the radial profile of this property was very similar to that of BD. There were significant differences in BD, CS and cell wall thickness of wood fibres among 10 selected logs, suggesting that BD and mechanical properties can be genetically improved by selecting mother trees.

Distortion and Residual Stress in High-Pressure Die Castings: Simulation and Measurements

Two individual high-pressure die casting geometries were developed to study the influence of process parameters and alloy composition on the distortion behavior of aluminum alloy castings. These geometries, a stress lattice and a V-shaped lid, tend to form residual stress due to a difference in wall thickness and a deliberate massive gating system. Castings were produced from two alloys: AlSi12(Fe) and AlSi10MnMg. In the experimental castings, the influence of important process parameters such as die temperature, ejection time, and cooling regime was examined. The time evolution of process temperatures was measured using thermal imaging. Subsequent to casting, distortion was measured by means of a tactile measuring device at ambient temperatures. The measured results were compared against a numerical process and stress simulations of the casting, ejection, and cooling process using the commercial finite element method software ANSYS Workbench. The heat transfer coefficients were adapted to the temperature distributions of the die, and the castings were observed by thermal imaging. A survey of the results of the comparison between simulation and experiment is given for both alloys.

FRI0235 Static and Dynamic-Functional Trans-Cervical Ultrasonography of the Esophagus in Systemic Sclerosis Patients

BackgroundEsophagus is the second internal organ to be affected in systemic sclerosis (SSc), resulting in gastro-oesophageal reflux, oesophagitis and, in more advanced stages, complete atony with megaesophagus. Trans-cervical ultrasonography (TCU)...

MP17-20 CHARACTERIZATION OF FUNCTIONAL BLADDER REGENERATION IN MICE

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology1 Apr 2014MP17-20 CHARACTERIZATION OF FUNCTIONAL BLADDER REGENERATION IN MICE Mona Zarifpour, Jason Sandberg, Mehran Abolbashari, Manasi Vadhavkar, Sneha Kelkar, Aaron Mohs, Frank Marini, Karl−Erik Andersson, and George Christ Mona ZarifpourMona Zarifpour More articles by this author , Jason SandbergJason Sandberg More articles by this author , Mehran AbolbashariMehran Abolbashari More articles by this author , Manasi VadhavkarManasi Vadhavkar More articles by this author , Sneha KelkarSneha Kelkar More articles by this author , Aaron MohsAaron Mohs More articles by this author , Frank MariniFrank Marini More articles by this author , Karl−Erik AnderssonKarl−Erik Andersson More articles by this author , and George ChristGeorge Christ More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.553AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Previous studies have established that subtotal cystectomy (removal of 60-70% of the bladder) provides a valid and unique model of mammalian organ regeneration (1,2). The goal of this study was to characterize this phenomenon in mice, a species that can be genetically engineered to investigate a diverse array of molecular alterations of functional bladder regeneration, including specific cell−based fluorescence imaging technologies. METHODS Female C57 black mice underwent STC, and at 4 and 12 weeks post−STC, bladder regeneration was assessed via cystometry and ex vivo pharmacologic organ bath studies. Histology was also performed to measure bladder wall thickness and the composition/architecture of the bladder wall. RESULTS We observed a time−dependent increase in bladder capacity following STC, such that 12 weeks post−STC, the sizes of regenerated bladders and micturition volumes were indistinguishable from those of age−matched controls (Fig. 1A, C). Bladders emptied completely at all time points studied (i.e., no increases in residual volume), consistent with functional bladder regeneration. There were no significant differences in bladder wall thickness (Fig. 1B) from controls, or in the percentage of smooth muscle in the detrusor layer (not shown). Contraction to pharmacological activation and electrical field stimulation were present in isolated tissue strips from regenerating bladders but were lower than controls at all time points. Initial cell and tissue transplantation studies using fluorescently labeled mice (i.e., transfer of green fluorescence protein bone marrow into red fluorescent protein animals) revealed a participation and contribution of bone marrow derived populations toward functional bladder regeneration. CONCLUSIONS This study extends our investigation of mammalian bladder regeneration from rats to mice. Establishing a validated model for the study of de novo organ regeneration in mice will allow for further characterization of this phenomenon through detailed investigation of its molecular and cellular basis. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e143 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Mona Zarifpour More articles by this author Jason Sandberg More articles by this author Mehran Abolbashari More articles by this author Manasi Vadhavkar More articles by this author Sneha Kelkar More articles by this author Aaron Mohs More articles by this author Frank Marini More articles by this author Karl−Erik Andersson More articles by this author George Christ More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

Greater thickness of the aortic wall on postmortem computed tomography compared with antemortem computed tomography: the first longitudinal study

To evaluate postmortem changes of the aorta on postmortem computed tomography (CT) in comparison with those on antemortem CT obtained in the same patients. We studied 57 consecutive patients who had undergone antemortem CT, postmortem CT, and pathological autopsy in our tertiary care hospital between April 2009 and December 2010. Postmortem CT was performed within 20 h after death, followed by pathological autopsy. Pathological autopsy confirmed the absence of cardiovascular disease such as aortic aneurysm, aortic dissection, or Marfan syndrome in all patients. Aortic wall thickness and aortic cross-sectional areas were measured on both antemortem CT and postmortem CT. Difference in aortic wall thickness between antemortem CT with and without contrast medium, and between antemortem CT and postmortem CT, and in cross-sectional area of the aortic wall between antemortem CT and postmortem CT was evaluated statistically. No significant difference in aortic wall thickness was observed on antemortem CT in comparison of contrasted and non-contrasted images. The aortic wall was significantly thicker on postmortem CT than on antemortem CT (p < 0.0001). No significant difference in cross-sectional area of the aortic wall was observed between antemortem CT and postmortem CT measurements. This is the first longitudinal study to confirm greater thickness of the aortic wall on postmortem images compared with antemortem images in the same patients and to show no change in cross-sectional area of the aortic wall between before and after death.

Early Changes in Apical Rotation in Genotype Positive Children with Hypertrophic Cardiomyopathy Mutations without Hypertrophic Changes on Two-Dimensional Imaging

Hypertrophic cardiomyopathy (HCM) is the most common form of inherited cardiomyopathy. Echocardiography is the mainstay of screening and disease surveillance, and genetic testing has identified a carrier population without hypertrophy. The aim of this study was to investigate whether changes in left ventricular (LV) function are detectable before the advent of hypertrophy. Fourteen children with genotype-positive, phenotype-negative HCM were identified (12 male; median age, 9.14 years; range, 1.91-15.9 years; median weight, 34.6 kg; range, 15-92.1 kg) and compared with age-matched and sex-matched healthy controls. All children underwent full echocardiographic studies using an extensive functional protocol, including two-dimensional dimensions, Doppler tissue imaging, and two-dimensional speckle-tracking echocardiography. There were no differences in LV wall thickness, chamber dimensions, length, and shortening fraction between the groups. Doppler tissue imaging in children with HCM demonstrated mildly reduced septal velocities, notably A' (5.9 cm/sec [range, 4-8.9 cm/sec] vs 6.7 cm/sec [range, 5.2-9.5 cm/sec]; P= .009). Circumferential and longitudinal strain was similar between groups. Mean apical circumferential deformation was increased in the HCM group (-24.6 ± 3.8% vs -22.2 ± 2.5%, P= .04). There were significant increases in basal and apical rotation and LV twist in children with HCM, most marked at the apex (11.7 ± 4.4° vs 5.3 ± 2.5°, P= .0001). On receiver operating characteristic curve analysis, apical rotation > 7° conferred 83% sensitivity and 82% specificity for predicting HCM (area under the curve, 0.919; P= .0001). Increased LV rotation and twist are present in children with genotype-positive, phenotype-negative HCM. Apical rotation on speckle-tracking echocardiography provides good sensitivity and specificity for the prediction of gene-positive HCM and may be a clinically useful early marker of HCM before the onset of hypertrophy.

Central artery stiffness, neuropsychological function, and cerebral perfusion in sedentary and endurance-trained middle-aged adults

Midlife vascular disease risk is a strong risk factor for late-life dementia. Central arterial stiffness, a hallmark of vascular aging, is associated with accelerated brain aging and cognitive decline. Habitual aerobic exercise is an effective lifestyle strategy to reduce central arterial stiffness and is related to lower risk of cognitive impairment. To determine the associations among cardiopulmonary fitness, neuropsychological function, central arterial stiffness, and cerebral perfusion in the sedentary and endurance-trained middle-aged adults. Twenty-six sedentary and 32 endurance-trained middle-aged adults were measured for maximal oxygen consumption, central arterial stiffness determined by aortic pulse wave velocity and carotid ultrasound, neuropsychological function, and regional cerebral blood flow assessed by MRI. There were no group differences in age, sex, ethnicity, education, blood pressure, and carotid intima-media wall thickness (all P>0.05). Neuropsychological performance and occipitoparietal perfusion were greater, and central arterial stiffness was lower in endurance-trained individuals than in sedentary individuals (all P<0.05). Greater cardiopulmonary fitness was related to better cognitive composite scores, including memory and attention-executive function (r=0.28-0.40, P<0.05). Lower carotid arterial stiffness was associated with better neuropsychological outcome independent of age, sex, and education (r=-0.32 to -0.35, P<0.05), and correlated with greater occipitoparietal blood flow (r= -0.37 to -0.51, P<0.05). Lower carotid artery stiffness in endurance-trained adults is associated with better neuropsychological outcome and greater occipitoparietal perfusion.

Heart Wall Is Thicker on Postmortem Computed Tomography Than on Ante Mortem Computed Tomography: The First Longitudinal Study

ObjectiveTo evaluate the postmortem changes of the heart wall on postmortem (PM) computed tomography (CT) in comparison with those on ante mortem CT (AMCT), and in comparison with the pathological findings, obtained in the same patients.Materials and MethodsWe studied 57 consecutive patients who had undergone AMCT, PMCT, and pathological autopsy in our tertiary care hospital between April 2009 and December 2010. PMCT was performed within 20 hours after death, followed by pathological autopsy. The cardiac chambers were measured at five sites on both AMCT and PMCT by two board-certified radiologists who were not provided with clinical information. The differences in heart wall thickness between AMCT with and without contrast medium, between AMCT and PMCT, and between PMCT and pathological anatomy were evaluated statistically. Confounding factors of postmortem change such as gender, presence of arteriosclerosis, the organ related to cause of death, age, and elapsed time since death were examined statistically.ResultsNo significant differences were observed on AMCT in comparison of contrasted and non-contrasted images. The heart wall was significantly thicker on PMCT than on AMCT (p < 0.0001) at all five measurement sites. The heart wall was significantly thicker on PMCT than on pathology specimens when measured in accordance with pathological standard mensuration. However, no significant difference was observed between PMCT measurements and those of pathology specimens at any site when the papillary muscles and epicardial fat were included. No significant association was found between postmortem change in heart wall thickness and gender, presence of arteriosclerosis, the organ related to cause of death, age, or elapsed time since death.ConclusionThis is the first longitudinal study to confirm greater thickness of heart wall on postmortem images compared with ante mortem images, in the same patients. Furthermore, the postmortem changes on CT were supported by the pathological findings.

CT angiographic imaging characteristics of thoracic idiopathic aortitis

BackgroundIdiopathic aortitis (IA) is characterized by giant cell or lymphoplasmacytic inflammation of aorta without a secondary cause. ObjectiveWe undertook a retrospective case–control study to identify characteristic CT angiographic findings in these patients and to correlate them with known atherosclerotic risk factors. MethodsIA cases and controls with noninflammatory aneurysm (control group I) and patients with secondary aortitis (control group II) were identified with a pathology database. Preoperative CT angiographic images of thoracic aorta were reviewed. Diameter of thoracic aorta, wall thickness, and calcification were measured at various sites. Traditional atherosclerotic risk factors were identified from case records and included hypertension, hyperlipidemia, diabetes mellitus, and smoking. ResultsTwenty-two idiopathic aortitis cases were compared with 18 patients in control group I and 16 patients in control group II. No differences were found in prevalence of hypertension and diabetes, but hyperlipidemia was more prevalent in the control group I than in cases (72% vs 36%; P = .03). Current smoking was more prevalent in cases (24%) than for patients in control group I (6%) and group II (19%) but not statistically significant (P = .18 and .69, respectively). Thoracic aortic diameters at various points were significantly larger in cases than for patients in control group I. Calcification was more frequent in cases than for patients in control group II. No differences in wall thickness were found. No meaningful correlation was observed between atherosclerotic risk factors and aortic diameter and calcification scores. ConclusionsPatients with IA have significantly larger and more diffuse dilatation of the thoracic aorta than patients with noninflammatory aneurysms.

Comparison of aortic wall quality between patients with coronary artery disease, aortic valve disease and aortic aneurysms

Background Currently no intraoperative test exists to predict postoperative dissection or aneurysm formation in patients operated for other reasons as aneurysms of the ascending aorta (AA). The aim of the present study was therefore to evaluate the mechanical and histological properties of the aortic wall in patients operated for coronary artery disease (CAD), aortic valve disease (stenosis (AS) or regurgitation (AR)), and for dilatation of AA of ≥ 45mm. Methods Aortic walls of 396 patients (age 67.0±10.8 years) operated for CAD (n=126), AS (n=126), AR (n=57) or AA (n=87), were subjected to mechanical stress testing and postoperative histological examination. The CAD patients served as the “negative control-group” ,w hereas the AA patients served as the “positive control-group”. The thickness of the aortic wall and TEE parameters (aortic annulus and sinus, sino-tubular junction and diameter of AA) were compared. Results The CAD group differed significantly compared to the AA group in all measured values (p<0.01), except the aortic wall thickness did not differ between the CAD and AA group. Comparing AS and AR patients presenting with CAD, (1) we observed statistically significant differences in TEE parameters and aortic wall thickness (p<0.05) and (2) we observed significant differences in the aortic wall cohesion between CAD and AI patients (p<0.05). Comparing the patients presenting with AA we observed statistically significant differences between patients with AS and AA (p<0.01). AR and AA patients differed only in TEE parameters. Furthermore, a total of 24% patients presented either with CAD or AS had a pathological cohesion test, whereas only in 18% the histological examination further confirmed these findings. Conclusion

Increased IGF-1 bioavailability preserves cardiac function and protects against diet-induced increases of blood pressure in high-fat fed mice

Purpose: Obesity is an established risk factor for cardiovascular disease, hypertension and left ventricular hypertrophy and is associated with a decline in plasma free IGF-I levels. This study evaluates the effect of high-fat feeding on cardiac and vascular function in mice with increased IGF-I bioavailability (IGFBP-1 knockout mice, BP1KO). Methods: Blood pressure was measured non-invasively after 8 and 16 weeks of feeding a 45% high fat diet. Cardiac structure and function was examined by echocardiography. Left ventricular and septum wall size was measured in systole and diastole. Doppler echocardiography measured mitral valve function. Mice were sacrificed and the heart and the left ventricle weighed. Results: After 8 and 16 weeks of high-fat feeding, BP1KO mice were protected against obesity-related hypertension (117.7 vs. 127 mmHg and 129.3 vs 143 mmHg BP1KO and WT respectively). At 16 weeks the left ventricular wall in systole was larger in the KO cohort, but stroke volume was preserved. At 24 weeks there was no difference in ventricular or septal wall measurements. Left ventricle to heart weight ratio was higher in the WT than the BP1KO mice (73.38% vs 69.20%). Mitral Valve Measurements Values expressed as mean±SEM. *p<0.05, **p<0.01. Conclusions: Increased IGF-1 bioavailability protected against the rise in blood pressure observed in obesity. Although there was no difference in ventricular wall thickness, the WT controls exhibited left ventricular hypertrophy in comparison to the BP1KO group. IGF-1 was shown to ameliorate high-fat diet induced cardiac dysfunction. Decreased E/A ratio, increased IVRT and IVCT, measures of diastolic dysfunction, were preserved in the BP1KO cohort. Our data shows that increased IGF-1 bioavailability protects against the cardiac dysfunction, left ventricular hypertrophy and hypertension normally associated with caloric excess.

Thickness of Magnesium Alloy Square Parts in Hydraulic Deep Drawing

Forming effect of square parts is influenced greatly by technical parameters in hydraulic deep drawing, and it is significative to investigate the parameters. The technical parameters which influence the cold forming effect (wall thickness difference and minimum wall thickness) were introduced in detail by numerical simulation method, including the load method of blank holder force, drawing speed, hydraulic pressure, etc. Furthermore, the reasonable technological parameters were concluded and the wall thickness distribution of magnesium alloy square parts was discussed in this paper. The results show that the cold formability of AZ31B magnesium alloy square parts could be improved when adopt reasonable technological parameters and blank holder force load path in hydraulic deep drawing.

Clinical value of double respiratory navigator-gated high-resolution black-blood coronary artery wall magnetic resonance imaging

To explore the value of phase ordering with automatic window selection(PAWS)and simultaneous multiple volume(SMV)algorithm double respiratory navigator-gated two-dimensional(2DNAV)dual inversion recovery(DIR)fast spin echo(FSE)high-resolution black-blood coronary artery wall magnetic resonance imaging(MRI)and evaluate its advantages and limitations. PAWS and SMV 2DNAV DIR FSE high-resolution black-blood MRI was performed in 21 healthy volunteers. The images were evaluated qualitatively by using four grades(grade 0can not evaluate;grade 1bad;grade 2good;grade 3perfect). Images defined as grade 0 and grade 1 were excluded and those defined as grade 2 and 3 were evaluated further. Thickness of proximal(or middle)segment of right coronary artery(RCA)and left anterior descending branch(LAD)were measured. The difference of wall thickness was analyzed by using two-tailed independent sample t-test. P values of less than 0.05 were considered statistically significant. Among the 38 slice images,31 slices(RCA13 slices,LAD18 slices;grade 214 slices,grade 317 slices)were obtained for further evaluation. The mean thickness of RCA and LAD was(0.94±0.16)and(0.89±0.15)mm,respectively,and the difference was not significant(t=-0.790,P>0.05). PAWS and SMV algorithm 2DNAV DIR FSE high-resolution black-blood MRI has certain clinical value for coronary artery wall imaging.

AB0777 Computed tomodensitometric (CT) angiographic imaging characteristics of idiopathic aortitis: A case control study

BackgroundIdiopathic aortitis is a rare condition characterized by giant cell or lymphoplasmacytic inflammation of aorta in absence of a secondary cause. No information is available on pre-operative imaging findings in...

The Development of Expanded Snack Product Made from Pumpkin Flour-Corn Grits: Effect of Extrusion Conditions and Formulations on Physical Characteristics and Microstructure.

Pumpkin products confer natural sweetness, desirable flavours and β-carotene, a vitamin A precursor when added as ingredients to extruded snacks. Therefore, a potential use for dried pumpkin flour is as an ingredient in ready-to-eat (RTE) snack foods. Growth in this market has driven food manufacturers to produce a variety of new high value snack foods incorporating diverse ingredients to enhance the appearance and nutritional properties of these foods. Ready-to-eat snacks were made by extruding corn grits with 5%, 10%, 15% and 20% of pumpkin flour. Snacks made from 100% corn grits were used as control products for this work. The effect of formulation and screw speeds of 250 rpm and 350 rpm on torque and specific mechanical energy (SME, kWh/kg), physical characteristics (expansion ratio, bulk density, true density and hardness) and the microstructure of the snacks were studied. Increasing the screw speed resulted in a decrease of torque for all formulations. When pumpkin flour was added the specific mechanical energy (SME) decreased by approximately 45%. Increasing the percentage of pumpkin flour at the higher screw speed resulted in a harder texture for the extruded products. X-ray tomography of pumpkin flour-corn grit snacks showed that increased levels of pumpkin flour decreased both the bubble area and bubble size. However, no significant differences (p > 0.05) in bubble wall thickness were measured. By understanding the conditions during extrusion, desirable nutritional characteristics can be incorporated while maximizing expansion to make a product with low bulk density, a fine bubble structure and acceptable organoleptic properties.

Sonographic assessment of first stage of labor progress (ULTRASONIC PARTOGRAM)

PurposeTo assess the role of ultrasound in the follow up of the progress of labor in terms of uterine wall thickness in its upper and lower segments. MethodsThis is a prospective cross sectional study conducted in the period from March 2012 to August 2012. Included a total of 43 low risk pregnant women at Dallah hospital, Riyadh, Kingdom of Saudi Arabia. Trans-abdominal ultrasound was used to measure the uterine wall thickness. ResultsWith the progress of labor, the upper uterine wall progressively thickened, while the lower uterine segment progressively thinned. A significant change in uterine wall thickness was found with every 2cm cervical dilatation. A sono-partogram was developed. There was no significant difference in uterine wall thickness with respect to gravidity. The upper/lower uterine wall thickness ratio may also be valuable in the assessment of the progress of labor. We found that, measuring the uterine wall thickness by trans abdominal US is a non invasive method which has the potential role for assessing the progress of labor especially in high risk pregnancies when digital examination carries the risk of ascending infection or bleeding as in patients with preterm labor, premature rupture of membranes or ante-partum hemorrhage. ConclusionsTrans-abdominal US is a new non invasive method and has the potential for assessing the progress of labor. A sono-partogram is very useful in the follow up and evaluation of the progress of labor.

Quantification and visualization of carotid segmentation accuracy and precision using a 2D standardized carotid map

This paper describes a framework for vascular image segmentation evaluation. Since the size of vessel wall and plaque burden is defined by the lumen and wall boundaries in vascular segmentation, these two boundaries should be considered as a pair in statistical evaluation of a segmentation algorithm. This work proposed statistical metrics to evaluate the difference of local vessel wall thickness (VWT) produced by manual and algorithm-based semi-automatic segmentation methods (ΔT) with the local segmentation standard deviation of the wall and lumen boundaries considered. ΔT was further approximately decomposed into the local wall and lumen boundary differences (ΔW and ΔL respectively) in order to provide information regarding which of the wall and lumen segmentation errors contribute more to the VWT difference. In this study, the lumen and wall boundaries in 3D carotid ultrasound images acquired for 21 subjects were each segmented five times manually and by a level-set segmentation algorithm. The (absolute) difference measures (i.e., ΔT, ΔW, ΔL and their absolute values) and the pooled local standard deviation of manually and algorithmically segmented wall and lumen boundaries were computed for each subject and represented in a 2D standardized map. The local accuracy and variability of the segmentation algorithm at each point can be quantified by the average of these metrics for the whole group of subjects and visualized on the 2D standardized map. Based on the results shown on the 2D standardized map, a variety of strategies, such as adding anchor points and adjusting weights of different forces in the algorithm, can be introduced to improve the accuracy and variability of the algorithm.

The Influence Wall Thickness of Cement Hollow Spheres towards Compressive Properties of Cement Syntactic Foam

An innovative technique in producing cement syntactic foam (CSF) was proposed in this investigation. This cellular composite material basically consists of a cement matrix embedded with in-house developed cement hollow spheres (CHS). The produced foams incorporated with CHS having different wall thickness, were characterized for compressive strength and then compared with that of plain cement. It was observed that the CSFs were 37%-55% lighter than the plain cement but possessed compromised compressive strength. The comparative compressive properties of CSFs were also evaluated and reported. It was found that the CSF incorporated with thicker-coated CHS showed higher compressive strength compared to that of incorporated with thinner-coated CHS. The failure patterns within the test samples were also examined to determine the failure mechanism. These observations showed that both CSFs exhibited shearing type failure but exhibit different types of crack fractures due to the difference in CHS wall thickness.

Characterization of the Vascular Phenotype of the Equilibrative Nucleoside Transporter 1 Knockout Mouse

Adenosine is important in the endogenous regulation of vascular tone. Equilibrative Nucleoside Transporter 1 (ENT1) is an established regulator of adenosine concentrations in vascular tissues. Thus, changes in ENT1 expression and/or activity may alter vascular tone regulation. We therefore examined the cardiovascular phenotype of ENT1‐knockout (KO) mice as compared to wild type (WT) mice. Heart rates and blood pressures of KO and WT littermate male mice were obtained. Vascular reactivity was assessed in aortic ring segments obtained from 3 and 6 month old KO and WT mice. KCl‐induced depolarization led to significantly greater constriction (~32% increase independent of tension applied or age) in KO rings compared to WT. However, no significant differences between the two genotypes were observed using a series of receptor‐selective constrictors. Morphological assessment of H&amp;E stained vascularized tissues yielded no significant difference in luminal area or arterial wall thickness between WT and KO mice at the age of 3 months. The enhanced effect of KCl in KO aortic rings suggests a physiological difference in the regulation of depolarization‐induced, but not receptor‐mediated, vasoconstriction response in aorta. Further assessment of this model will aid in our understanding of the role of adenosine in vascular regulation.

Noninvasive Ultrasound Molecular Imaging of the Effect of Statins on Endothelial Inflammatory Phenotype in Early Atherosclerosis

Background/ObjectivesInflammatory changes on the endothelium are responsible for leukocyte recruitment to plaques in atherosclerosis. Noninvasive assessment of treatment-effects on endothelial inflammation may be of use for managing medical therapy and developing novel therapies. We hypothesized that molecular imaging of vascular cell adhesion molecule-1 (VCAM-1) with contrast enhanced ultrasound (CEU) could assess treatment effects on endothelial phenotype in early atherosclerosis.MethodsMice with atherosclerosis produced by gene deletion of the LDL-receptor and Apobec-1-editing protein were studied. At 12 weeks of age, mice received 8 weeks of regular chow or atorvastatin-enriched chow (10 mg/kg/day). At 20 weeks, CEU molecular imaging for aortic endothelial VCAM-1 expression was performed with VCAM-1-targeted (MBVCAM) and control microbubbles (MBCtr). Aortic wall thickness was assessed with high frequency ultrasound. Histology, immunohistology and Western blot were used to assess plaque burden and VCAM-1 expression.ResultsPlaque burden was reduced on histology, and VCAM-1 was reduced on Western blot by atorvastatin, which corresponded to less endothelial expression of VCAM-1 on immunohistology. High frequency ultrasound did not detect differences in aortic wall thickness between groups. In contrast, CEU molecular imaging demonstrated selective signal enhancement for MBVCAM in non-treated animals (MBVCAM 2±0.3 vs MBCtr 0.7±0.2, p<0.01), but not in statin-treated animals (MBVCAM 0.8±0.2 vs MBCtr 1.0±0.2, p = ns; p<0.01 for the effect of statin on MBVCAM signal).ConclusionsNon-invasive CEU molecular imaging detects the effects of anti-inflammatory treatment on endothelial inflammation in early atherosclerosis. This easily accessible, low-cost technique may be useful in assessing treatment effects in preclinical research and in patients.