bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exposure to Fullerene C60 Nanoparticles Impairs Lung Mechanics and Mitochondrial Function
Authors: Zin Walter A. , Caldeira Dayene F. , Pinheiro Felipe G. , Maciel Leonardo , Oliveira Dahienne F. 
Published: April 2020

C60 fullerene (C60) carbon‐based nanoparticles are widely used because of their physicochemical properties, and are released into the atmosphere from anthropogenic or natural sources. Due to its small size (0.65–0.7 nm) and electronegative chemical behavior, C60 can overcome natural biological barriers and deposit onto the respiratory system. However, the literature does not fully describe its putative pulmonary burden. C60 interaction with double membrane organelles like mitochondria, housing enzyme systems that convert metabolism by‐products into usable energy (ATP) and are an important source of oxygen‐derived free radicals, has been recently described. We hypothesized that C60 impairs lung function and alters its inflammatory status via mechanisms possibly involving mitochondria. Hence, we addressed pulmonary mechanics, histology and mitochondrial function after a single exposure to C60. Our Institutional Ethics Committee approved the study (code: 155/18). Thirty‐five male BALB/c mice were randomly divided into 2 groups intratracheally (it) instilled with vehicle (0.9% NaCl + 1% Tween 80, CTRL) or C60 (1.0 mg/kg, FUL). Twenty‐four hours after exposure, 15 FUL and 8 CTRL mice were anesthetized (10 mg/kg xylazine and 120 mg/kg ketamine), paralyzed (pancuronium bromide, 0.1 mg/kg) and mechanically ventilated for the determination of lung mechanics. They were then euthanized by sectioning of abdominal aorta and vena cava; the lungs were extracted at FRC for histological processing. Results are expressed as median, 25th and 75th percentiles. FUL group showed increased lung tissue elastance (FUL=38.21, 32.43, 39.83 vs CTRL=31.63, 29.31, 33.41 cmH2O/mL, p=0.0049) and viscance (FUL=4.44, 3.72, 4.76 vs CTRL=3.73, 3.36, 3.87 cmH2O/mL, p=0.0225). In addition, lung histology disclosed increased inflammatory cell number (FUL=16.0, 14.6, 18.8 vs CTRL=9.2, 8.8, 9.6 10−3/μm2 cells, p=0.0022) and alveolar collapse (FUL=11.33, 10.34, 13.79 vs CTRL=5.78, 4.69, 7.71%; p=0.0286), septal thickening and pulmonary edema. The remaining 6 FUL and 6 CTRL mice were expertly euthanized by cervical dislocation. Mitochondrial function expressed reduction in state 1 respiration in the presence of pyruvate‐malate substrates [FUL=3.0±1.14 vs CTRL=4.46±0.9 (SEM) nmol O2/min/mg protein, p=0.0210], ATP production (FUL=122.6±18 vs CTRL=154.5±14 μmol/100 μg protein, p=0.0340), and higher generation of reactive oxygen species (ROS) (FUL 733.1±169.32 vs CTRL=486.39±73.1 nmol/100 μg protein, p=0.0313). In conclusion, exposure to fullerene C60 impaired lung mechanics and mitochondrial function, increased ROS concentration, and triggered pulmonary tissue inflammation.Support or Funding InformationCNPq, FAPERJ, FINEP, CAPES
Effect of Continuous‐Flow Left Ventricular Assist Device Support on Coronary Artery Endothelial Function in Ischemic and Non‐Ischemic Cardiomyopathy
Authors: Symons J David , Deeter Lance , Deeter Nicholas , Bonn Trevor , Cho Jae Min , Ferrin Peter , McCreath Lauren , Diakos Nikolaos , Taleb Iosif , Alharethi Rami , McKellar Stephen , Wever-Pinzon Omar , Navankasattusas Sutip , Selzman Craig , Fang James , Drakos Stavros 
Published: April 2020

The coronary vasculature encounters a reduction in pulsatility after implementing durable continuous‐flow left ventricular assist device (CF‐LVAD) circulatory support. Evidence exists that appropriate pulsatility is required to maintain endothelial cell homeostasis. We hypothesized that coronary artery endothelial function would be impaired after CF‐LVAD intervention. Coronary arteries from patients with end‐stage heart failure caused by ischemic (ICM, n=16) or non‐ischemic (NICM, n=22) cardiomyopathy were isolated from the LV apical core which was removed for the CF‐LVAD implantation. In 11 of these patients, paired coronary arteries were obtained from an adjacent region of myocardium after the CF‐LVAD intervention (n = 6 ICM, 5 NICM). Vascular function was assessed ex vivo using isometric tension procedures in these patients and in 7 non‐failing donor controls. Maximal endothelium‐dependent vasorelaxation to bradykinin (BK, 10−6 to 10−10 M) was blunted (p<0.05) in arteries from patients with ICM compared to NICM and donor controls, whereas responses to sodium nitroprusside (SNP, 10−4 to 10−9 M) were similar among the groups. Contrary to our hypothesis, vasorelaxation responses to BK and SNP were similar before and 219±37 days after CF‐LVAD support. Of these patients, an exploratory subgroup analysis revealed that BK‐induced coronary artery vasorelaxation was greater (p<0.05) after (87±6%) vs. before (54±14%) CF‐LVAD intervention in ICM patients, while SNP‐evoked responses were similar. Coronary artery endothelial function is not impaired by durable CF‐LVAD support, and in ICM patients appears to be improved. Investigating coronary endothelial function using in vivo approaches in a larger patient population is warranted.Support or Funding InformationJDS (AHA16GRNT31050004, NIH RO3AGO52848, NHLBI RO1 HL141540); LD, ND, TB (University of Utah Undergraduate Research Opportunities Program); JMC (University of Utah Graduate Research Fellowship); SGD (AHA Heart Failure Strategically Focused Research Network 16SFRN29020000, NHLBI RO1 HL135121, NHLBI RO1 HL132067).
Glypican‐1 Is a Trigger for Pulmonary Edema Development During Acute Heart Failure
Authors: Chignalia Andreia Z. , Isbatan Ayman , Black Stephen M. , Dull Randal O. 
Published: April 2020

Heart Failure is a growing global epidemic with a prevalence of over 37.7 million cases. Accumulating evidence indicate that the lungs actively participate in the pathogenesis of Heart Failure and, in particular, in the development of pulmonary edema associated with acute heart failure (AHF). The molecular mechanisms by which pulmonary edema develops during AHF are not clarified but increases in pulmonary capillary pressure may play a role. Herein we sought to investigate if glypican‐1 (Gpc1), a heparan sulfate proteoglycan known to be activated by pressure, contributes to hyperpermeability and pulmonary edema during AHF. We hypothesize that Gpc1 induces pulmonary edema via eNOS uncoupling and RhoA nitration. The isolated perfused lung preparation was used to simulate AHF in male CD‐1 (wild type, WT) and glypican‐1 knockout (Gpc1KO) mice (6 weeks old). Control experiments were done setting left atria pressure (PLA) at 3cm H2O for 10 minutes; AHF was simulated by setting PLA at 10 cm H2O for 10 minutes. Lung edema was assessed by lung wet‐to‐dry ratio; heart function was assessed by echocardiography, reactive oxygen species (ROS) production was assessed by lucigenin enhanced chemiluminescence. PKCa activation, eNOS phosphorylation at T495 and Rho nitration were assessed by immunoblotting. An in vitro approach was taken to further investigate the molecular mechanisms by which increased pressure leads to endothelial hyperpermeability: human lung microvascular endothelial cells (HLMEC) were exposed or not to high hydrostatic pressure (30cm H2O) for 10 minutes and analysis of activation of PKC‐eNOS‐RhoA axis was performed by immunoblotting. WT and Gpc1KO mice showed similar ejection fraction and increase in pulmonary artery pressure. Deletion of Gpc1 protected mice from pulmonary edema associated with AHF and prevented increase on ROS production. Inhibition of eNOS with L‐NIO mitigated pulmonary edema during AHF in WT mice. NOC‐9, a NO donor, restored the ability of GPC1KO lungs to develop edema during AHF. Moreover, WT mice showed increased eNOS phosphorylation at T495, PKCa activation and RhoA nitration during AHF, effects not seen in Gpc1KO. In vitro, increased hydrostatic pressure induced activation of the same pathways as seen in the in situ model. Taken together, these results suggest that activation of Gpc1 leads to eNOS uncoupling and RhoA nitration that results in endothelial hyperpermeability and pulmonary edema during AHF. These data evidence the lung endothelium as an active player during AHF and glypican‐1 as a gatekeeper of barrier function.Support or Funding InformationP01 HL134610 (SMB) and funds from the Department of Anesthesiology, College of Medicine, University of Arizona, Tucson and the Department of Anesthesiology, College of Medicine, University of Illinois at Chicago.
Dsg2 Upregulation as a Rescue Mechanism in Pemphigus
Authors: Sigmund Anna M. , Egu Desalegn T. , Waschke Jens , Vielmuth Franziska 
Published: April 2020

In the bullous autoimmune disease pemphigus, autoantibodies directed against the desmosomal cadherins desmoglein (Dsg)1 and 3 cause loss of intercellular adhesion clinically manifested as flaccid blisters of the skin and mucous membranes. We showed that homophilic Dsg3 interactions are directly inhibited upon autoantibody binding and recently observed that Dsg3 also undergoes heterophilic interactions with Dsg2. Thus, we here investigated the impact of this heterophilic interaction in pemphigus. Dsg2, which is almost absent in healthy, adult epidermis, was upregulated in epidermis of pemphigus patients. Similarly, pemphigus autoantibodies induced upregulation of Dsg2 in a human ex‐vivo skin model. Further, a newly generated stable murine Dsg3‐deficient keratinocyte cell line showed severely disturbed intercellular adhesion in keratinocytes dissociation assay paralleled by upregulation of Dsg2 in the cytoskeletal‐bound membrane fraction. Heterophilic interactions were confirmed by Dsg2‐Dsg3 co‐immunoprecipitation in human keratinocytes. We next characterized heterophilic Dsg2‐Dsg3 interactions by cell‐free atomic force microscopy, which showed binding frequency, ‐strength, Ca2+‐dependency and a catch‐bond behavior comparable to the homophilic Dsg3 interaction. A pathogenic pemphigus aDsg3 antibody from a pemphigus model, AK23, and autoantibodies from a pemphigus patient directly interfere with homophilic Dsg3 binding. Interestingly, direct inhibition was significantly less pronounced for heterophilic Dsg3‐Dsg2 interactions. In contrast, an aDsg2 blocking antibody reduced heterophilic Dsg3‐Dsg2 and homophilic Dsg2‐Dsg2 binding to the same degree. Consequently, the aDsg2 antibody severely impaired already disturbed intercellular cohesion of Dsg3‐deficient keratinocytes, underlining the importance of Dsg2 for intercellular adhesion if Dsg3 is missing. Moreover, heterophilic Dsg2‐Dsg3 interactions showed a longer life‐time compared to homophilic Dsg2‐Dsg2 interactions which may contribute to their biological importance when Dsg3 homophilic interactions are compromised. Taken together, the data show that Dsg2 undergoes heterophilic interactions with Dsg3, which may serve as a compensatory mechanism to attenuate autoantibody‐induced loss of keratinocyte adhesion in pemphigus. This further reflects the biological significance of heterophilic Dsg3 interactions under pathological conditions.Support or Funding InformationDFG FOR 2497 to JW, Else‐Kröner‐Fresenius‐Stiftung 2016_AW157 to FV
Exploring the Rap1A Active Site Through Accelerated Molecular Dynamic Simulations
Authors: Schwabe Michael , Holzapfel Genevieve , Mattos Carla 
Published: April 2020

GTPases are hydrolytic proteins that convert GTP to GDP and serve as bivalent switches, where the GTP‐bound state is active, and the GDP‐bound state is inactive. Although Ras is the archetypal GTPase, Rap1A is closely related with 50% sequence homology and similar tertiary structure; a key difference occurs at position 61. In Ras Q61 participates in the hydrolysis mechanism and mutation leads to oncogenesis, while T61 in Rap1A is not thought to be involved in catalysis. The goal of this project is to explore the Rap1A active site and method of intrinsic hydrolysis. Two crystal structures were obtained with differing conformations of T61 in the Rap1A active site. Accelerated molecular dynamic simulations were run for 200 ns to sample the variety of motion present in Rap1A. Results indicate coordinated movements between the switch I, switch II, and helix 3 regions. Further, switch II appears less mobile than simulations with Ras isoforms.Support or Funding InformationMCB‐1517295, MCB‐0818678
Efficacy of In‐Class Drawing Activities on Clinical Anatomy of the Vagus Nerve
Authors: Mansour Yusra , Kulesza Randy J. 
Published: April 2020

IntroductionIn class drawing has been shown to enhance learning and promote long term retention in anatomy and medical education. There has, however, been little research into the effect of instructor‐guided interactive drawing sessions on clinical anatomy compared to textbook reading as well as the effect of drawing on technology (i.e. tablets, ipads) compared to drawing on paper.AimWe set out to investigate the effect of student’s preferred learning style (i.e. visual, non‐visual) on learning after instructor guided interactive drawing sessions using anatomy of the vagus nerve and compare this to more traditional resources such as lecture and textbooks.MethodsIn order to explore the effects of interactive drawing sessions and use of technology, we recruited novice first year medical students. Students were asked to complete the Index of Learning Styles questionnaire to determine preferred learning style and categorize students as either visual or non‐visual learners. Students were further sorted into 1 of 4 groups including a drawing on paper group, drawing on technology group, lecture group and a reading group and participated in a learning session on the anatomy of the vagus nerve. Learning sessions involved an anatomy pre‐test and a post‐test to assess learning. Both pre and post‐test included functional, structural, clinical and dissection‐based questions. Long‐term retention will be assessed 6 months after the primary learning session with another anatomy post‐test. Students were also asked to participate in a survey asking their opinion on the effectiveness of their session. Data collection and statistical analysis will be completed by Feb 2020. The protocol was approved by the Institutional Review Board (protocol # 26‐167).ResultsPreliminary results of pre‐ to post‐test analysis suggest an increase in post‐test scores in each of the four groups, with a greater improvement in non‐reading groups compared to that of the reading group. Students in the drawing and lecture groups performed better than those in the reading group on clinical case‐based questions. On the post‐session survey, non‐readers preferred their particular learning sessions, were more likely to recommend more sessions be added to the curriculum and felt their learning session taught them anatomy better than reading a textbook.ConclusionWe interpret these results to suggest that instructor guided drawing and lecture sessions lead to enhanced learning and clinical comprehension as well as increased student satisfaction compared to reading.
HMGB1‐induced vascular hyperpermeability requires β‐catenin phosphorylation
Authors: Guo Xiaohua 
Published: April 2020

Endothelial hyperpermeability is a hallmark of acute lung injury in response to sepsis. The imbalance between adherence junction (AJ) mediated cell‐cell adherence forces and stress fiber driven contractile forces contributes to increased endothelial permeability. Here, we spotlight the effects of β‐catenin Y654 andY142 phosphorylation on HMGB1‐mediated endothelial barrier leakage. Our results showed that phospho‐deficiencies at both β‐catenin Y654 and Y142 ameliorated pulmonary vascular dysfunction in male C57 mice receiving a cecal ligation and puncture operation. In vitro analysis indicated that high mobility group box‐1 protein (HMGB1) triggered β‐catenin Y654 and Y142 phosphorylation, causing β‐catenin translocation and adherence junction (AJ) disruptions as well as cytoskeleton rearrangement. In addition, β‐catenin Y654 dephosphorylation attenuated HMGB1‐mediated dissociation of VE‐cadherin/β‐catenin and, hence, partially prevented endothelial hyperpermeability. β‐catenin Y142 dephosphorylation abolished HMGB1‐induced uncoupling of β‐catenin and α‐catenin, suppressed cytoskeletal reassembly and, hence, alleviated endothelial hyperpermeability. Further investigation demonstrated that RAGE and Src were required for β‐catenin Y654 phosphorylation in response to HMGB1, while FAK was responsible for HMGB1‐triggered β‐catenin Y142 phosphorylation. In sum, this study revealed the role of β‐catenin Y654 and Y142 phosphorylation in HMGB1‐mediated endothelial hyperpermeability through dysregulation between adherence and contractile forces. This result advances understanding of the mechanisms underlying pulmonary vascular hyperpermeability in sepsis.Support or Funding InformationThis work was supported by National Natural Science Foundation of China (81670076, 31871183); Guangdong Natural Science Foundation (2017A030313462); General Program from Natural Science Foundation of China (81370226, 81170297); The Team project of Natural Science Foundation of Guangdong, China (S2013030013217); Grant of NSFC Guangdong Joint Foundation of China (U1601225); Key Scientific and Technological Program of Guangzhou City (201607020016); Special Funds for the Cultivation of Guangdong College Students’ Scientific and Technological Innovation [pdjh2017a0095].
Effect of temperature fluctuations on larval function of the Baja California chorus frog, Pseudacris hypochondriaca
Authors: Ramirez Marie , Manzanares Samantha , Mueller Casey A. 
Published: April 2020

Environmental temperature has an extensive impact on the phenotypes of all animals.Temperature fluctuations, often experienced naturally across daily or longer cycles, may cause profound effects on physiological phenotypes of animals, particularly during development and in ectotherms like amphibians. This study tested this hypothesis by evaluating the effects of temperature fluctuations during the larval development of the eurythermal Baja California chorus frog (Pseudacris hypochondriaca), a species native to southern California and northern Baja California. Eggs were collected from ponds in San Marcos, California within 24 hours of fertilization and separated into four temperature treatments: 15°C constant, and fluctuating treatments over 24 hours of 12.5°C – 17.5°C, 10°C – 20°C, and 15°C – 25°C. Oxygen consumption rate (V̇o2), critical thermal maximum (CTMAX), and swim speed were measured for tadpoles at 15°C during hindlimb toe development. Relative to mass‐specific V̇o2 in 15°C constant tadpoles, mass‐specific V̇o2 measured at 15°C showed a slight increase in 12.5°C – 17.5°C tadpoles, a larger increase in 10°C – 20°C tadpoles, but no difference in 15°C – 25°C tadpoles. Relative to CTMAX in 15°C constant tadpoles, CTMAX was similar in 12.5°C – 17.5°C tadpoles, slightly higher in 10°C – 20°C tadpoles, and greatly increased in 15°C – 25°C tadpoles. Swim speed measured at 15°C was similar across all temperature treatments. Overall, greater fluctuations had stronger effects on larval V̇o2 and CTMAX, and tadpoles tend to acclimate to higher temperatures during daily cycles. Acclimation in thermal tolerance and metabolic rates of this eurythermal amphibian indicates the animals will likely show plasticity in some traits in response to fluctuating temperatures. Future studies will examine these traits across a range of acute measurement temperatures to fully understand the functional implications of fluctuating temperatures.
Invasive Physiological Measurements in Patients with Peripheral Artery Disease: Willingness and Barriers to Participation
Authors: Muller Matthew D. , Levenberg Kate , Luck J. Carter , Miller Amanda J. , Maman Stephan R. , Aziz Faisal , Radtka John F. , Proctor David N. 
Published: April 2020

Invasive physiological measurements such as microneurography, arterial and venous catheterization, and central neuraxial anesthesia are necessary to investigate mechanisms of cardiovascular control in humans. To date, these procedures have not been utilized in patients with peripheral artery disease (PAD). The purpose of this project was to quantify the willingness, motivating factors, and barriers to participating in invasive physiological experiments in adults with and without PAD. Data were gathered through focus groups (n = 19 participants age 55–79) and questionnaires (n = 2543 mailed, 438 adults age 18–85 responded). Of the people who returned the questionnaire, 90% were willing to participate in ultrasound assessment of vascular function and 76% were willing to undergo a venous blood draw, whereas only 40% were willing to participate in microneurography, 30% were willing to undergo arterial or venous drug infusions, 12% were willing to receive spinal or epidural anesthesia, and 14% were willing to undergo a muscle biopsy. PAD patients (n=45) were more willing than those without PAD (n=360) to participate in drug infusion studies (48% vs 18%, P<0.001) and trials of investigational drugs (44% vs 21%, P<0.001). The participants also provided feedback on our recruitment materials and made suggestions to increase enrollment in our ongoing randomized controlled trial. In the past three years, some of these strategies have been implemented. Based on our focus groups and questionnaire data, we speculate that engaging PAD patients in all aspects of the research process will lead to better recruitment and retention as compared to the “standard of care” (i.e., spending large amounts of money on radio and television advertising, printed brochures, searching electronic medical records, and direct mailing). However, this remains to be directly tested in future studies.Support or Funding InformationThis project was supported by NIH R21 AG054940 (to Dr. Proctor). This project was also supported, in part, by National Center for Advancing Translational Sciences Grants UL1 TR002014, UL1 TR‐000127 and KL2 TR‐000126 and also under a grant with the Pennsylvania Department of Health using Tobacco CURE funds (to Dr. Muller).