bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impaired Microvascular Endothelial Function in Preeclampsia
Authors: McIntosh Jennifer Jury , Derayunan Alexa , Hader Shelby , Lohr Nicole , Beyer Andreas , Gutterman David 
Published: April 2020

RationalWomen with preeclampsia (PE) have compromised endothelial function (assessed by brachial artery flow‐mediated dilation) compared to normal women. Placental and uterine spiral artery endothelial dysfunction is seen in PE pregnancies. Human studies remain incomplete, as most approaches have been unable to eliminate neural, humoral, paracrine influences on vessel response. Direct evaluation of the placental arterioles will allow a more direct analysis of vasodilatory responses as related to the endothelial dysfunction in PE.ObjectiveTo study placental endothelial function in preeclamptic (PE) and normal placental vessels.MethodsTo examine the impact of PE on the microvascular function, isolated vessels from placentas of healthy and PE pregnancies were used for videomicroscopy. Endothelial‐dependent dilation to flow (FMD), acetylcholine (ACh) and smooth muscle‐dependent dilation to papaverine were evaluated. Data are presented as a percentage of maximum diameter and were analyzed with 2‐way ANOVA RM with statistical significance set at *p<0.05; data are expressed as mean ± SE.ResultsVessels from PE patients resulted in impairment of FMD (control 71.% ±6.6%, PE 31.6%±10.7%*) and dilation to Ach (control 63.6%±9.4, PE 32.7±8.83%*). Smooth muscle‐dependent dilation to papaverine was unchanged between the two groups (Figure
).ConclusionPreliminary studies show impaired endothelial function in placental vessels of subjects with PE, compared to healthy controls, while smooth muscle function was not affected. Understanding the underlying mechanism(s) of vasodilation in placental vasculature will further the understanding the pathophysiology of PE.Support or Funding InformationThe project described was supported by the National Center for Advancing Translational Sciences, National Institutes of Health, Award NumberUL1TR001436. The content is solely the responsibility of the author(s) and does not necessarily represent the official views of the NIH. This project is funded by the Research and Education Program Fund, a component of the Advancing a Healthier Wisconsin Endowment at the Medical College of Wisconsin.Vessels from PE patients resulted in impairment of FMD and dilation to ACh. Smooth muscle‐dependent dilation to papaverine was unchanged between the two groups. Statistical significance denoted with *Figure 1
CFTR‐mediated transepithelial bicarbonate conductance is affected differently than chloride conductance by CFTR correctors and potentiators
Authors: Schultz Bruce D , Bridges Robert J 
Published: April 2020

The advent of targeted CFTR therapeutics allows us to assess differences in epithelial Cl− and HCO3− conductances that might be attributed to unique combinations of CFTR variants (mutations), CFTR modulators (corrector(s) and potentiators) as well as secretory agonists. To address these questions, Fisher rat thyroid cells expressing wt or mutant CFTR were cultured on permeable supports for the measurement of transepithelial conductance (Gt) in defined ionic conditions. Initial experiments demonstrated stepwise reduction in the forskolin (Forsk)+ivacaftor (VX770)‐stimulated change in Gt as bath NaCl was partially replaced isosmotically with mannitol. Subsequent experiments were conducted in buffers containing 100 mEq/l Cl− with the addition of either 25 mM alternative anions (Na+ salts) or 50 mM mannitol. Outcomes showed forskolin‐induced Gt changes consistent with reported CFTR permselectivity: Cl− > NO3− ≥ Br− > isethionate ≥ gluconate > mannitol. All subsequent experiments were conducted to assess Gt with 100 mEq/l Cl− plus either 25 mEq/l HCO3−, 50 mM mannitol or 25 mEq/l Cl−, in a 5% CO2 atmosphere. Epithelia expressing wtCFTR respond to forskolin with a substantial increase in Gt. The response in HCO3− was ~75% of that observed with Cl−. Exposure to VX770 increased conductance, but a disproportionately lesser change was observed in HCO3− (vs. Cl−), providing an initial suggestion that VX770 promotes differential ion selectivity.Exposure of cells expressing F508del CFTR to correctors, either C17 or C18, allowed for forskolin‐induced stimulation of Gt with a modest increment of HCO3− conductance. In these conditions, VX770 induced additional Cl− conductance, but no enhancement of HCO3− conductance could be detected. Alternatively, cells exposed to the corrector combination (C17+C18) showed a substantial forskolin‐stimulated increase in anion conductance and a modest increase in CFTR‐associated HCO3− conductance. Thus, the combination of C17 and C18 gives a different outcome regarding F508del‐CFTR HCO3− conductance than either corrector alone.Cells expressing G551D CFTR exhibited little response to forskolin, but substantial responses to VX770. Responses to VX770 in HCO3− approached the magnitude of the responses observed in Cl−.Taken together, the results suggest that CFTR correctors and potentiators can enhance CFTR‐mediated anion conductance, but that significant differences in the conductances of HCO3− relative to Cl− are observed between CFTR variants and that responses can be influenced by the correctors employed. Ultimately, these results suggest that CFTR‐associated pH regulation will be impacted by both the patient’s mutation and the CFTR modulator treatment. Furthermore, additional studies are required to evaluate the CFTR modulators for their effects on Cl− and HCO3− conductances on the many CF causing CFTR variants.Support or Funding InformationCFF BRIDGE18XX0; K‐State CVM SMILE
Variation in Fractional Flow Reserve (FFR) and Its Effects on Stenting Decision Making
Authors: Handly Neal , Heyndrickx Guy R. , Kerkhof Peter L. 
Published: April 2020

FFR is an important construct using intra‐arterial pressures to describe blood flow past partial stenoses in coronary arteries to determine the need for percutaneous coronary intervention. Point estimates of the FFR can be compared to two threshold values to determine three decision "zones ": FFR <0.75 such that stenting (S) of this lesion should be performed, 0.75<FFR≤0.80 such that additional evaluation (AE) prior to final decision on stent placement is needed and FFR>0.80 which indicates that no stenting (NS) of the lesion should occur at this time.Variation of FFR measurements would be expected due to factors at the operator, protocol, and instrument levels. Subject physiology, such as the level of venous pressure, collateral flow, heart rate and size /geometry of the stenosis, can also have an effect. This variation might lead to errors in the decision making process. However, FFR variability is poorly described in the literature and trade documents.This study was designed to explore the role of FFR variability on probabilities of errors in decision making when measuring a FFR value that was considered to be normally distributed about 0.74, 0.78 and 0.81 (being examples of true values that may occur in each of the decision zones) and with four different standard deviations (SD) in the measure of FFR.Normal distributions of these FFR were generated with SD of 0.01, 0.02, 0.029 and 0.05 with resampling software (J. Grosberg, Statistics101 Version 4.9). These SD values were based on repeated FFR measures on 6 subjects (Aalst, GRH), from which an average deviation of 0.029 was found. The 0.01, 0.02 and 0.05 SD values were included to further explore their effect on FFR distributions. Probabilities of FFR measures that would be found in zones S, AE and NS were generated to show the frequency of erroneous versus true FFR values.The results for each chosen FFR and SD combination are given in the accompanying table, showing probabilities of FFR measures in the S, AE and NS zones.In general, the greater the variation as described by the SD, the greater is the probability of any single measurement being incorrect (i.e., being found in a zone different from its true value). The variability in FFR measurement should be quantified since it has bearing on possible errors in decision making as well as serving guidance in technique improvement. Efforts to assure low variability are important.

FFR 0.74

SD

Zone

S

AE

NS

(true S)

0.01

0.841

0.159

0.000

0.02

0.692

0.307

0.001

0.029

0.635

0.346

0.019

0.05

0.579

0.306

0.115

FFR 0.78

SD

(true AE)

0.01

0.001

0.976

0.023

0.02

0.066

0.775

0.158

0.029

0.151

0.604

0.245

0.05

0.275

0.380

0.345

FFR 0.81

SD

(true NS)

0.01

0.000

0.158

0.842

0.02

0.001

0.308

0.691

0.029

0.019

0.345

0.636

0.05

0.115

0.306

0.579
The Correlation between Common Variable Immunodeficiency and Atrial Fibrillation: Cardiac Implantable Electronic Devices‐associated infection by Stenotrophomonas maltophilia: A case report
Authors: Tsai Jeffrey , Nguyen Nam H. , Dylewski John R. 
Published: April 2020

BackgroundCommon variable immunodeficiency (CVID) is associated with systemic infections and autoimmune diseases which may elicit and perpetuate atrial fibrillation via inflammatory and oxidative mechanisms. CVID patients with early‐onset atrial fibrillation (AF) and chronic heart failure (CHF) are refractory to standardized cardiac ablation and frequently need sophisticated cardiac resynchronization therapy. Moreover, CVID‐CHF patients with cardiac implantable electronic devices (CIEDs) are vulnerable to opportunistic infection, especially Stenotrophomonas maltophilia bacteremia, which has high resistance to a variety of empirical antibiotics against gram negative bacteremia.Case presentation31 year‐old female with a past medical history of chronic refractory AF, CHF, thyroid cancer, non‐Hodgkin lymphoma, and factor V deficiency presented to the hospital with a fever of 104.0F for 2 days after recent dual‐chamber biventricular defibrillator replacement 2 weeks ago. 2 months ago, the patient was diagnosed with CVID due to recurrent cardiopulmonary infections. Upon this admission, the patient’s blood culture demonstrated S. maltophilia which was likely from the complications of CIEDs placement.ConclusionEarly‐onset Atrial fibrillation in young population may be a feature of CVID. Early recognition of CVID in these patients, especially with comorbidity of CHF, can mitigate the progression of AF with antioxidants as well as promptly identify and manage CIEDs‐associated infections, such as S. maltophilia.Figure 1
Understanding the Molecular Underpinnings of Neuronal Kinase CDK5 mediated Metabolic Vulnerabilities in Neuroendocrine Tumors
Authors: Gupta Priyanka , Strange Keehn , Carter Angela , Telenge Rahul , Meijer Laurent , Ghayee Hans , Pacak Karel , Reddy Sushanth , Bibb James 
Published: April 2020

BackgroundAberrantly activated neuronal kinase CDK5 invoke alternations in mitochondrial dynamics and metabolic dysfunction associated with neurological disorders. Although pro‐tumorigenic role of CDK5 has been recently defined but there is insufficient data to understand the mechanistic role of CDK5 in cancer associated mitochondrial structure and function.HypothesisIn this study we intend to investigate putative signalling hotspots downstream of aberrantly activated CDK5 in neuroendocrine tumors of adrenal glands called Pheochromocytoma (PC).ApproachOur preliminary data for the first time showed deregulation of Ca2+ homeostasis and overexpression of CDK5 and its co‐activators‐p35/25 in malignant PC tumors inflicted with loss‐of‐function mutations in mitochondrial enzyme‐Succinate dehydrogenase B (SDHB). To elucidate role of CDK5 in tumorigenesis, we created a novel bi‐transgenic mouse model where doxycycline inducible overexpression of CDK5/p25 (p25OE) developed organ specific PC lesions.ResultsPhopshoproteomic analysis on p25OE PC tumors unraveled a tumor suppressive mechanism modulated by novel phosphorylation site on metabolic protein‐PRKAG2 (S‐65). PRKAG2 is a non‐catalytic regulatory subunit of AMP‐activated protein kinase (AMPK). S‐65 site on PRKAG2 were found downregulated in human PC tumors compared to normal adrenal medulla. Further biochemical characterization uncovered CDK5‐GSK3β‐AMPK crosstalk underlying human PC cellular proliferation. Picking CDK5 pocket with a novel CDK5 inhibitor ‘MRT3‐007’ induced anti‐proliferative effects with simultaneous increase in phosphorylation states of PRKAG2(S‐65) / AMPK(T‐172) sites followed by excessive mitochondrial fission.ConclusionThese intriguing initial findings set the ground to discover therapeutic vulnerabilities associated with CDK5/p25/PRKAG2/AMPK signaling cascade and Mitochondrial Dynamics in Neuroendocrine tumors.Schematic depiction of working model demonstrating a novel crosstalk between a metabolic sensor ‘PRKAG2/AMPK’ and ‘Mitochondrial Fission’ synapsed via neuronal kinase ‘CDK5/p25’ in Pheochromocytoma (PC tumors) inflicted with mutations in SDHB gene.Figure 1
Time Constant and Length Constant: Graphical Illustrations for Effective Teaching and Learning
Authors: Luedtke Alyssa , Lewis Austin , Kuang Serena Y. 
Published: April 2020

IntroductionThis is a teacher‐guided students’ presentation. The time constant (τ) and the length constant (λ) are the cell membrane’s passive cable properties that influence the velocity of the spread of graded potentials and thus the velocity of the propagation of action potentials. In teaching and learning the electrophysiology of the cell membrane, we noticed that the information about the two concepts in many current physiology textbooks are incomplete and inconsistent. Some books introduce both τ and λ, whereas some other books do not introduce them. Some books introduce only τ, whereas some other books introduce only λ. Some books use the rising phase of a graded potential to illustrate τ, whereas some other books use the falling phase. Graphical illustrations about these concepts are generally not available in these physiology textbooks. This situation makes it confusing for students to understand the two concepts. In this presentation, we address the above problems and share our figures to facilitate the learning of the two concepts.MethodTextbook comparisons and graphical illustrations.Results1) The incompleteness and the inconsistency about the two concepts will be addressed in a table using a few sampled textbooks. 2) A set of figures (not shown) are used to provide a complete illustration about τ in both the rising phase and the falling phase of a graded potential; and the rising phase is then used to graphically illustrate how τ affects the propagation of an action potential (Figure
1). 3) How λ affects the propagation of an action potential is illustrated graphically using the falling phase of a graded potential (Figure
2).ConclusionGraphical illustrations are of great value for the effective teaching and learning of the concepts of time constant and the length constant.Time constant (τ) determines how fast a local current depolarizes Vm to Vthreshold to trigger an action potential.Figure 1Length constant (λ). A: The λ influences the spread of a local current (or the graded potential it generates). The greater the λ, the farther the local current (or the graded potential) spreads. B: The greater the λ, the farther the local current (or the graded potential) spreads, so the more voltage‐gated Na+ channels (VGSCs) in a regional area are likely to open and the faster the AP propagation. VGKC: voltage‐gated K+ channels.Figure 2
Reductions in Microvascular Function can be Detected by Near‐infrared Spectroscopy (NIRS) following Ischemia‐Reperfusion in Early Postmenopausal Women
Authors: Somani Yasina B. , Soares Rogerio N. , Gosalia Jigar , Delgado Jocelyn , Murias Juan M. , Proctor David N. 
Published: April 2020

The onset of menopause and accompanying changes to ovarian hormones often precedes endothelial dysfunction in women. In particular, accelerated impairments in microvascular function coincides with the loss of estrogen, as does impaired endothelial resilience to ischemia‐reperfusion (IR) injury. In early postmenopausal women (4 ± 1 years since menopause), we tested the hypothesis that the NIRS‐derived measurement of vascular responsiveness (reoxygenation slope, %.s−1) in the forearm could detect reductions in microvascular function following whole‐arm IR injury. In conjunction, brachial artery flow‐mediated dilation (FMD) and shear rate (area under curve; AUCpeak) were measured. Thirteen healthy, normotensive (116 ± 11/72 ± 9 mmHg) postmenopausal women (57 ± 3 years) were tested before (PreIR), after (PostIR), and 15 minutes following IR (Post15). The IR injury was achieved by inflating a cuff around the upper‐arm to 250 mmHg for 20 min followed by 15 min of reperfusion. The NIRS‐derived reoxygenation slope was lower PostIR (1.02 ± 0.56%.s−1 vs. 1.23 ± 0.64%.s−1 PreIR; p =0.04), but not at Post15 (1.17 ± 0.51%.s−1; p =0.08). Brachial artery FMD was lower PostIR (3.57 ± 0.52% vs. 8.14 ± 2.44% PreIR; p < 0.001), but not at Post15 (7.61 ± 1.89%; p = 0.54). Shear AUCpeak were similar across tests (p >0.05). Our findings suggest that the NIRS‐derived reoxygenation slope is a non‐invasive method that may detect transient impairments in forearm microvascular function, and may also be used to assess efficacy of therapeutic interventions in improving both vascular function and resilience in this population.Support or Funding InformationPenn State Human Health and Development Endowment AwardSchematic of study timelineFigure 1
Structural Basis of Protein Kinase C Tumor‐Promoting Response And Membrane Recruitment
Authors: Igumenova Tatyana I. , Katti Sachin , Yu Binhan , Cole Taylor R. 
Published: April 2020

Protein Kinase C (PKC) is a family of Ser/Thr kinases that regulate a multitude of cellular processes through participation in the phosphoinositide signaling pathway. The hallmark of their activation is translocation to lipid membranes. Dysregulation of PKC signaling has been implicated in cancer progression, cardiac disease, and Alzheimer’s disease. One of the major challenges in the field is to understand the structural basis of PKC activation and regulation ‐‐ at the level of atomic resolution.Here, we applied NMR and FRET spectroscopy to gain insight into the structure and protein‐membrane interactions of the regulatory domain of PKC that consist of three peripheral membrane modules: the tandem conserved homology‐1 (C1) and conserved homology‐2 (C2) domains. The C1 domains undergo membrane insertion upon binding their natural agonist, diacylglycerol, as well as tumor‐promoting phorbol esters and other small‐molecule agonists. C2 associates with anionic membranes upon binding Ca2+. Simultaneous association of all domains with membranes ensures the coincidence of four signals: Ca2+ ions, diacylglycerol, phosphatidylserine, and phosphatidylinositol‐4,5‐bisphosphate.Here, we report the first structure of the C1 domain complexed to a potent tumor‐promoting agent, phorbol 12,13‐dibutyrate (PDBu), in the membrane‐mimicking environment. The structure of the complex shows that C1 has to undergo a conformational change in order to capture the membrane‐embedded ligand. The structure also revealed the role of individual amino acids in the interactions with PDBu and membrane‐mimicking environment. To probe how different agonists modulate the interaction of C1 with membranes, we conducted NMR paramagnetic relaxation enhancement (PRE) experiments with bicelles doped with paramagnetic lipid. The PRE patterns revealed that the C1 domains adopt tilted rather than vertical orientation in the membrane. Our data on four different agonists indicate that C1 domains dictate the general orientation of the agonist complexes in the membrane, but the agonists determine the depth of insertion. This provides a plausible explanation for the differences in the potency of these ligands to achieve the acute and chronic activation response of PKC.To gain insight into the mechanism of coincidence detection, we developed protein‐to‐membrane FRET assay that we used to characterize the interplay of the C1 and C2 domains in the membrane association step. The FRET experiments revealed a clear picture of how tumor‐promoting agents can elicit constitutive activation of PKC through simultaneous recruitment of C1 domains to membranes and sensitization of the C2 domain to Ca2+.Support or Funding InformationNIH R01 GM108998; NSF CHE‐1905116; Welch Foundation A‐1784Agonist‐guided membrane interaction of C1B domain of PKCδ studied by paramagnetic NMR. (A) Schematic representation of the approach. (B) Chemical representations of the different agonists used in the study.Figure 1
Pancreatic Stellate Cells Serve as a Brake Mechanism on Pancreatic Acinar Cell Calcium Signaling with Modulation by Methionine Sulfoxide Reductase Expression
Authors: Cui Zong Jie , Liu Jin Shuai 
Published: April 2020

Although methionine sulfoxide reductase (Msr) is known to modulate activity of multiple functional proteins, roles of Msr in pancreatic stellate cell physiology have not been reported. In the present work we investigated expression and function of Msr in freshly isolated and cultured rat pancreatic stellate cells. Msr expression was determined by RT‐PCR, Western blot and immunocytochemistry. Msr over‐expression was achieved by transfection with adenovirus vectors. Pancreatic stellate cells were co‐cultured with pancreatic acinar cells AR4‐2J in monolayer culture. Pancreatic stellate and acinar cell function was monitored by Fura‐2 calcium imaging. Rat pancreatic stellate cells were found to express MsrA, B1, B2, their expressions diminished in culture. Over‐expressions of MsrA, B1, or B2 were found to enhance ATP‐stimulated calcium increase but decreased reactive oxygen species production and lipopolysaccharide‐elicited IL‐1 production. Pancreatic stellate cell‐co‐culture with AR4‐2J blunted cholecystokinin‐ and acetylcholine‐stimulated calcium increases in AR4‐2J, depending on acinar / stellate cell ratio, this inhibition was reversed by MsrA, B1 over‐expression in stellate cells or by Met supplementation in co‐culture medium. Different from the pancreatic acinar cells, although pancreatic stellate cells also express the cholecystokinin 1 receptor, the receptor is not coupled to calcium signaling. In addition, Msr‐overexpression only partially restored cholecystokinin 1 receptor coupling to the calcium signaling pathway in pancreatic stellate cells, whereas addition of free Met in the culture medium had no effect. These data suggest that Msr play important roles in pancreatic stellate cell function and the stellate cells may serve as a brake mechanism on pancreatic acinar cell calcium signaling modulated by stellate cell Msr expression. Pancreatic stellate cell cholecystokinin 1 receptor is de‐coupled from calcium signaling, Msr overexpression only partially restores cholecystokinin‐stimulation of calcium increases at high CCK concentrations in the stellate cells.Support or Funding InformationThis work was supported by grants from NSFC (31670856, 31971170).Figure 1