bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of physical training on hind limb blood flow with femoral artery occlusion in pigs
Authors: Terjung Ronald L , Yang Hsiao Tung , Bowles Douglas K , Laughlin M. Harold 
Published: June 2021

Physical training (PT) is an important regimen for intermittent claudicants. To develop collateral circuit supporting the large muscle mass in large mammals, requires development of large caliber conduit vessels. To study whether PT enhances to develop large collateral conduits, male Yucatan pigs (35 kg) received femoral artery occlusion. Flow probes were placed on each external iliac artery and the pigs were given a stress test each wk for eight wks (@1‐5 mile/h). BP in the thoracic aorta was monitored. Pigs were either kept in cage activity (Sed) or ran on treadmill @ 3.5 mi/hr for 35 min/d, for 8 wks (Tr). BP during exercise declined (35%) after PT. Peak BF through the iliac artery observed increased in both Sed and Tr pigs similarly over 8 wks (643±83 to 913±26 ml/min). This increase in BF is similar to the 250±25 ml/min measured in the unobstructed contralateral femoral artery during the same exercise intensity. Thus the increased BF was attributed to collateral flow via the newly formed collateral vessels that were later verified angiographically. BF though the iliac artery remained modestly elevated post‐exercise, compared to the non‐obstructed contralateral iliac artery, characteristic of an ischemic hyperemia response. Our findings demonstrate that a robust collateral vessel development occurs following occlusion of the supply vessel in a large mammal.Supported by NIH P01HL 52490
Gap junction coupling‐mediated membrane potential oscillations drive activity in cutaneous but not muscle vasoconstrictor sympathetic preganglionic neurones in situ
Authors: Stalbovskiy Alexey O , Paton Julian F , Pickering Anthony E 
Published: June 2021

A population of sympathetic preganglionic neurones (SPN) recorded in vitro show gap junction‐mediated oscillations in membrane potential that underlie their spike discharge (Logan et al, 1996, J Physiol), but the role of such coupling in vivo is uncertain. We made whole‐cell recordings from functionally identified SPN in the rat (aged p5‐16) working heart‐brainstem preparation (WHBP, (Paton, 1996, J Neurosci Meths)) to examine the neural mechanisms generating their firing activity.108 SPNs identified in the T3‐4 segment were functionally categorised by responses to activation of peripheral chemoreflex (NaCN, ia) and diving response (cold to snout). Muscle vasoconstrictor (MVC, 38%) SPN were activated by both tests and converseley cutaneous vasoconstrictor (CVC, 27%) SPN were inhibited by both. MVCs had a higher baseline firing frequency in comparison with CVC (2.6±0.3 vs. 1.4±0.3 Hz; p=0.007) and shorter after‐hyperpolarization (156±10 vs. 296±39 ms, p=0.0001). MVC SPN showed a respiratory‐modulated pattern of firing generated by a torrent of kynurenate‐sensitive, excitatory synaptic inputs. By contrast, the activity of CVC SPN was driven by large, slow, biphasic membrane potential oscillations (n=14 of 15 examined) that resembled filtered action potentials which were relatively insensitive to membrane potential, not blocked by spinal kynurenate and were indistinguishable from those previously reported in vitro. Antidromic activation of CVC SPN evoked short latency depolarization confirming the presence of coupling.These findings indicate that gap junctional coupling plays an important functional role in the patterning and synchronization of the output from CVC but not MVC SPN.Funded by BHF.
A potential role for the ROS‐HIF‐VEGF pathway in hypoxia‐induced pulmonary vascular leak
Authors: Irwin David , McCord Joe , Majka Susan , Klemm Dwight 
Published: June 2021

AbstractAcute hypoxia causes pulmonary vascular leak and is involved in the pathogenesis of pulmonary edema associated with inflammation, acute altitude exposure, and other critical illnesses. Reactive oxygen species, HIF‐1 and VEGF have all been implicated in various hypoxic pathologies, yet the ROS‐HIF‐1‐VEGF pathway in pulmonary vascular leak has not been defined. We hypothesized that the ROS‐HIF‐1‐VEGF pathway has an important role in producing hypoxia‐induced pulmonary vascular leak. Human pulmonary artery endothelial cell monolayers (HPAEC) were exposed to either normoxia (21% or acute hypoxia (3% for 24 h and monolayer permeability, H2O2, nuclear HIF‐1α, and cytosolic VEGF were determined. HPAEC were treated with antioxidant cocktail (AO: ascorbate, glutathione, and α‐tocopherol), HIF‐1 siRNA, or VEGF soluble binding protein (sFlt‐1) to delineate the role of the ROS‐HIF‐1‐VEGF pathway in hypoxia‐induced HPAEC leak. Additionally, mice exposed to hypobaric hypoxia (18,000 ft, 10% O2) were treated with the same antioxidant to determine if in‐vitro responses corresponded to in‐vivo hypoxia stress. Hypoxia increased albumin permeability, H2O2 production, nuclear HIF‐1α, and cytosolic VEGF concentration. Treatment with an AO lowered the hypoxia‐induced HPAEC monolayer permeability as well as elevation of HIF‐1α and VEGF. Treatment of hypoxia‐induced HPAEC with either a siRNA designed against HIF‐1α or VEGF antagonist soluble fms‐like tyrosine kinase (sFlt)‐1 decreased monolayer permeability. Mice treated with AO and exposed to hypobaric hypoxia had less pulmonary vascular leak than those that were untreated. Our data suggest that hypoxia‐induced permeability is due, in part, to the ROS‐HIF‐1α ‐VEGF pathway.
Hypercapnia inhibits both transient and sustained potassium currents in chemosensitive neurons from neonatal rat locus coeruleus (LC)
Authors: Li Ke‐Yong , Putnam Robert W. 
Published: June 2021

Increased ventilation is stimulated by an increase in CO2/H+, which is detected by peripheral chemoreceptors and central chemosensitive neurons. We studied CO2/H+‐sensitive K+ channels in rat LC neurons. We hypothesize that multiple ion channels are involved in the neuronal response to changes in CO2/H+, with K+ channels being an important component mediating this response. In this study, we used whole cell voltage clamp to test the effect of 15% CO2 on both transient and sustained K+ currents of LC neurons from neonatal rat brain slices. Neurons were clamped at ‐80mV. Voltage‐dependent K+ currents were evoked by various depolarizing pulses (300 ms duration) in 10 mV increments from ‐100mV to 50mV in the presence of TTX (1 μm) and Cd2+ (200 μm) to block Na+ and Ca2+ channels, respectively. Transient K+ currents were inhibited by 4‐amino pyridine (4‐AP; 5mM) and sustained K+ currents were inhibited by tetraethylammonium (TEA; 20mM). Five minutes after perfusion with aCSF equilibrated with 15% CO2, the conductances of both transient and sustained K+ channels were decreased by 28 ± 9.5% (n=3) and 19 ± 9.6% (n=3), respectively. These results support the hypothesis that hypercapnia increases the firing frequency of LC neurons through depolarization due to inhibition of multiple K+ channels, including transient and sustained K+ conductances.Supported by NIH Grant R01‐HL56683‐11.
Na+/Ca2+ Exchange and Airway Smooth Muscle Inflammation
Authors: Venkatachalem Sathish , Thompson Michael , Pabelick Christina , Prakash Y S , Sieck Gary C 
Published: June 2021

Airway inflammation leads to increased intracellular Ca2+ ([Ca2+]i) in airway smooth muscle (ASM). There is now growing evidence that the bidrectional plasma membrane Na+/Ca2+ exchange (NCX) may contribute to ASM [Ca2+]i regulation. However, the roles of NCX‐mediated Ca2+ influx vs. efflux, or the role of NCX in airway inflammation are largely unknown. In the present study, we examined NCX expression and function in human ASM exposed to the pro‐inflammatory cytokines TNFα and IL‐13. Western blot analysis of human ASM tissue showed significant expression of the NCX1 isoform, with substantial increase in expression following overnight cytokine exposure. In fura‐2 loaded human ASM cells, NCX‐mediated Ca2+ influx as well as efflux (measured as slopes of changes in [Ca2+]i) was elicited using techniques previously described for cardiac muscle. Contribution of NCX was verified by measuring [Na+]i using the fluorescent Na+ indicator SBFI. NCX‐mediated influx was verified by demonstrating prevention of rising [Ca2+]i or falling [Na+]i in the presence of the NCX inhibitor KBR7943. In second set of studies, NCX siRNA transfection of human ASM substantially blunted efflux and influx mode of NCX (siRNA effect verified by Western blot). Exposure to TNF‐α as well as IL‐13 significantly enhanced influx mode of NCX. Although both cytokines also increased efflux mode of NCX, these effects were relatively smaller. These data suggest that NCX may be one mechanism contributing to inflammation‐induced enhancement of [Ca2+]i.Supported by NIH grants HL74309, RR024150, and the Flight Attendants Medical Research Institute (FAMRI). Additional funding from the Department of Anesthesiology, Mayo Clinic.
T Wave Alternans Observed on Intracardiac Bipolar Electrograms Predicts Ischemic Ventricular Tachycardia Due to Focal and Reentrant Mechanisms
Authors: Chaudhary Ashok K. , Ely Debra R. , Dove Edwin , Martins James B. 
Published: June 2021

Recently T Wave Alternans (TWA) measured on intracardiac electrograms has been shown to predict ventricular tachycardia (VT) in animal models and in patients with implantable defibrillators. We measured intracardiac bipolar electrograms (IBE) recorded in 3‐D from ischemic and normal zones in the acutely ischemic heart to predict location and mechanism of VT.Methods18 alpha chloralose anesthetized dogs were studied with 3‐D mapping after coronary artery occlusion (CAO); infarct size (IS) was measured as % of all IBE recorded which had voltage drop >45%. Mapping localized the 3‐D origin of spontaneous VT. TWA was measured on the body surface (TWA‐surf) as well as on IBE (from up to 62 anterior septal transmural sites measured by visual estimate) filtered from 3‐1300 Hz (TWA‐IBE).ResultsTWA‐surf correlated with IS in the first 30 minutes of CAO; thereafter it did not. TWA‐surf correlated with the number of IBE with TWA found in normal and ischemic sites in both epicardium and endocardium. Compared to hearts without VT the density of TWA on IBE sites was greater in hearts with VT (4.8 ± 1.7 SE vs 19.5 ± 2.6, p<0.05) Spontaneous VT tended to be focal endocardial (56%) had TWA‐IBE at the site of origin in 81%. However epicardial reentry had only 54% sites, p<0.05 vs focal, with TWA‐IBE.ConclusionTWA‐surf correlates well with TWA‐IBE. TWA‐IBE is a marker of VT regardless of mechanism. Density of TWA predicts VT.
Effect of PDIII inhibitor (Cilostazol) on ischemic angiogenesis in diabetic mice
Authors: Otagiri Aoi , Matsushita Shonosuke , Sakakibara Yuzuru 
Published: June 2021

PurposeCilostazol (Cil) is a Class A drug for peripheral arterial disease (PAD) and used worldwide. Since diabetes mellitus (DM) is a main exacerbating factor of PAD, the effect of Cil on ischemic angiogenesis is investigated to clarify its beneficial effect on DM in regard to cellular and local components.MethodsMale mice (n=18) were divided into three groups; Control (C), DM (D), and DM? (L). DM was induced by streptozocin. Cil was administered by oral intake. Femoral artery was ligated in all mice. 2 months after operation, mice were evaluated by (1) capillary density of soleus muscle, (2) Laser Doppler flow meter of posterior tibial artery, (3) number of endothelial progenitor cells (EPCs) by FCM, (4) analysis of immunohistochemistry (IHC) by eNOS antibody.ResultsCapillary density was decreased in DM compared to Control, however, DM? recovered to control level (C 15.1 7.6, D 9.6 4.1, L 14.1 3.5 per field; X400, p<0.05 C vs D, p<0.005 D vs L). Laser Doppler flow was as follows: (C 849%, D 6413%, L 63 6%, p<0.05 C vs D, p<0.001 C vs L). There was no difference in the number of EPCs among three groups (C 84, D 82, L 75 per µl). Mice with Cilostazol increased eNOS expression than DM by semiquantitative analysis (p<0.001).ConclusionCilostazol enhanced angiogenesis in diabetic ischemic limb. It is not due to the involvement of bone‐marrow derived EPCs, but may due to enhanced eNOS expression.
High salt diet during pregnancy: effects on the renin ‐angiotensin‐aldosterone system in adult male offspring of Wistar rats
Authors: Ramos Débora Rothstein , Costa Nauilo L. , Oliveira Ivone B. , Lopes Karen L. , Heimann Joel C. , Furukawa Luzia NS. 
Published: June 2021

ObjectiveTo study the effect of high salt intake during pregnancy on the renin‐angiotensin system, COX‐2 and nNOS in adult male offspring of Wistar rats.Methods and ResultsFemale Wistar rats were fed with normal salt ‐ NSD (1.3%), high salt 1 ‐ HSD1 (4.0%) or high salt 2 HSD2 (8.0% NaCl) diet during pregnancy. Dams after delivery and offspring after weaning were fed NSD.Table (mean ± SEM): Parameters analyzed in 12 week‐old offspring. * p <0.05 vs. NRConclusionHigh sodium intake during pregnancy induces changes in renal renin‐angiotensin‐aldosterone system, COX‐2 and nNOS in male offspring of Wistar rats.Financial SupportFAPESP
An experimental and theoretical study of DAF‐FM activation by NO: Toward calibration of an NO‐sensitive fluorescent dye
Authors: Namin Shabnam M. , Joshi Mahesh S. , Bautista Carolina , Nofallah Sara , Tsoukias Nikolaos M. 
Published: June 2021

The quantitative measurement of NO in vitro has been hampered by the lack of a method that can detect nanomolar levels with spatial and temporal resolution and without interference from other reaction byproducts. 4,5 diaminofluorescein (DAF‐FM) is a sensitive NO fluorescence probe used widely for qualitative but not quantitative assessment of cellular NO production. With the aid of a mathematical model of NO/DAF‐FM reaction kinetics, we have conducted experimental studies to calibrate the fluorescence signal and estimate NO generation in different systems. Kinetic analysis suggests the following dependence of DAF‐FM triazole (DAF‐T) generation rate:DAF‐T fluorescence was measured in a series of experiments with varying DAF‐FM and NO donor concentrations (spermine/NO). Experiments showed that the slope of fluorescent intensity is proportional to [NO]2 and exhibits a Monod type dependence on DAF‐FM concentration, thus validating the proposed kinetic mechanism. A calibration procedure was formed and applied in a cell culture system. Human umbilical vein endothelial cells (HUVEC) were stimulated with hemodynamic and agonist stimuli and the release rate of NO was assessed.[Supported by AHA grant NSDG043506N and NIH grant HL095101]
Courses in modeling transport and metabolism in cardiovascular and respiratory systems
Authors: Raymond Gary M. , Butterworth Erik A. , Bassingthwaighte James B. 
Published: June 2021

The National Simulation Resource, Department of Bioengineering, University of Washington, Seattle, will give two courses this summer in modeling transport and metabolism in cardiovascular and respiratory systems. The courses are designed for clinical and research scientists interested in quantitative analysis of biological systems. The focus is on approaches to data analysis, from the use of mathematical models for precision in hypothesis formulation to experimental design and evaluation by fitting models to data. Participants are encouraged to bring data and models for group discussion. The participants will make extensive use of computer models from www.physiome.org/Models and will develop new models using standard tools including JSim, a simulation system for building and analyzing quantitative models primarily in physiology and biomedicine. JSim runs on PC, Mac, and Linux platforms and is free and downloadable from www.physiome.org/jsim/download/index.html.Course 1, June 14‐19, 2009, emphasizes biophysics and physiology of transport and metabolism in these systems. Course 2, August 23‐28, emphasizes the translation of basic science models to clinical situations. (Supported by NIH T15 HL088516.)
Computerized Dog Lab for Teaching Cardiovascular Physiology to First Year Medical Students
Authors: Cornish Kurtis G , Zucker Irving H 
Published: June 2021

PurposeTo provide the students with an experience similar to that provided through animal labs but without using animals.MethodsDogs were chronically instrumented to demonstrate cardiovascular function and reflexes. This included aortic, left atrial and left ventricular catheters (LV), aortic and coronary flow probes, inferior vena cava, coronary artery and aortic occluders and in some instances LV dimension crystals. This allowed demonstration of the cardiac cycle and the direct and reflex responses to various interventions in conscious animals. The interventions included increasing and decreasing preload and afterload with drugs or vascular occluders, injecting an alpha or beta agonist, nitroglycerine or veratradine into the left atria. Reactive hyperemia was demonstrated with coronary occlusion.ResultsData were obtained over a period of years, negating the need for animals in student labs. The data were organized in a html format allowing the playback of avi files or figures showing the response to the intervention. For more advanced analysis the Chart 5 program (ADInstruments) was used.ConclusionThis lab has repeatedly been very highly evaluated by the students. They appreciate observing the integration of the cardiovascular system without using animals for their "educational use." This lab has replace much of the experience previously obtained with live animal labs.
Potential role of ATF2 and MEF2C in shear stress‐mediated VEGF production
Authors: Gee Eric , Fudalewski Tomasz , Haas Tara 
Published: June 2021

Increased capillary shear stress in skeletal muscle causes a form of angiogenesis termed luminal splitting. An increased number of capillaries are observed at 7 days of chronic shear stress that is reliant on p38 signaling. Others have shown that VEGF is essential for luminal splitting. We hypothesize that VEGF production is p38 dependent and is increased by p38 dependent transcription factors Creb, ATF2 and MEF2C in response to shear stress. Male Sprague‐Dawley rats were administered prazosin (50 mg/L drinking water) to increase shear stress, and the extensor digitorum longus was extracted at 1, 2, 4 or 7 days. By Western blot, p38 was activated only at 2 days. Skeletal muscle endothelial cells were sheared (12 dynes/cm2) with or without 10 μM SB203580 (p38 inhibitor), then lysed and analyzed by RT‐PCR or Western blot. In vitro, shear stress induced VEGF mRNA and protein elevation at 2 and 6 hours, respectively. These increases were abolished by SB203580. Shear stress increased both ATF2 phosphorylation and MEF2C production at 2 hours, which were abrogated by SB203580. Creb phosphorylation was unchanged by shear stress. Our data show that shear stress‐mediated p38 activation is required for VEGF production. ATF2 phosphorylation and MEF2C production are increased by shear stress, but further investigation is necessary to determine if they mediate p38‐induced VEGF production. Supported by HSF and NSERC.Grant Funding SourceThe Heart and Stroke Foundation
Keratin hydrogel increases survival time in femoral artery injury model via potential platelet adhesion mechanism
Authors: Rouse Jillian , Burnett Luke , Orebaugh Clinton , Stahle Mary , Hantgan Roy , Van Dyke Mark 
Published: June 2021

Keratin hydrogel is shown to be hemostatic in a porcine lethal extremity hemorrhage model compared to gauze and HemCon control groups with the presumptive mechanism of action being platelet adhesion and aggregation. Results showed that keratin hydrogels reduced shock index and increased survival time in comparison to both HemCon and gauze. Experiments to elucidate the mechanism of keratin hemostasis showed that platelets readily adhered to hydrogel films and that adherent cells contained numerous pseudopods, indicative of activation. Studies employing integrin function‐blocking antibodies reduced platelet adhesion. Collectively, these studies indicate that keratin promotes hemostasis via platelet adhesion by an integrin‐mediated process. Keratin hydrogels were shown to promote hemostasis and increase survival time in a lethal hemorrhage model with platelet adhesion and activation as the likely basis for the hemostatic property of keratin biomaterials.This work was supported by the US Army, SNS Nanofiber Technologies, American Heart Association, and Mid‐Atlantic Affiliate Grant‐in‐Aid.
Oxidative stress in diabetic pregnancy alters gene expression and apoptosis leading to congenital heart defects in embryos
Authors: Kumar S.D. , Cheng Y.J. , Lo S.L. , Kang Y.J. , Bay B.H. , Tay S.S.W. 
Published: June 2021

Congenital heart defects are frequently present in infants of diabetic mothers. The present study investigated the role of oxidative stress in the developing hearts of embryos from diabetic mothers. SuperArray analysis showed significant alterations of metabolic oxidative stress‐related genes (Gpx3, Fancc, Hbq1, Il22, Nqo1, Sod2 and Tmod1) in the hearts of experimental embryos. Further, the lipid hydroperoxidation level was significantly upregulated in the developing hearts of embryos from diabetic mothers. Western blot confirmed that the protein level of malondialdehyde (MDA) was significantly upregulated in the defective hearts. In addition, MTS assay was performed to assess the viability of H9C2 cell line (cardiomyoblasts) exposed to different glucose concentrations at various time points. Cell viability was significantly decreased in cardiomyoblast cultures treated with high glucose concentrations at all time points studied. Transmission electron microscopy confirmed that apoptotic cell death was upregulated in cardiomyoblasts exposed to high glucose concentrations. It is hypothesized that oxidative stress from maternal diabetes alters the expressions of genes and apoptosis which are involved in the development of the heart, thereby contributing to congenital heart defects.Supported by grants R‐181‐000‐101‐112 & R‐181‐000‐117‐101 from National University of Singapore.Grant Funding SourceAAA Postdoctoral Travel Award & AAA Postdoctoral Fellow Poster Presentation Award
Functional TRPC5‐containing channels in human saphenous vein endothelial cells
Authors: Bahnasi Yahya M , O'Regan David J , Porter Karen E , Beech David J 
Published: June 2021

Vascular endothelium plays pivotal roles in regulation of vascular tone, blood coagulation, wound healing and cell‐cell adhesion via the expression of vasoactive mediators. Ca2+ plays a central role in the regulation of endothelial cell function. Classical transient receptor potential channels (TRPC1‐7) are widely expressed and some are suggested to play critical roles in regulating endothelial functions. Here, we demonstrate the expression and functionality of TRPC5‐containing channels in human saphenous vein endothelial cells (HSVEC). RT‐PCR analysis suggested that TRPC1, 4, and 5 are expressed in HSVEC. Cells were then studied using fura‐2 real‐time 96‐well plate assays. Challenging of HSVEC with 10 µM histamine or lysophosphatidylcholine (LPC), 1 mM H2O2 or 100 ng/mL vascular endothelial growth factor (VEGF) induced rises in [Ca2+ ]i, which was inhibited by a TRPC5‐specific polyclonal antibody. The inhibition varied from ~80% in the case of LPC, to ~40, 50 and 70% for the histamine, H2O2 and VEGF responses. ATP (100 µM) mediated Ca2+ rise was not affected. Our data support earlier murine studies, and suggest the involvement of TRPC5‐containing channels in mediating Ca2+ signals in human endothelial cells. The channel may be important in inflammatory, oxidative or angiogenic conditions, and is a potential target for therapeutic development.Work supported by the Wellcome Trust and The Egyptian Ministry of Higher Education.Grant Funding SourceWellcome Trust and Egyptian Ministry of Higher Education