bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidative stress and hypoxia‐related stem cell death
Authors: Peterson Karen M , Abdelrhaman Aly , Rodriguez‐Porcel Martin 
Published: June 2021

BackgroundStem cells undergo significant death after transplantation, but the mechanisms underlying this deleterious response remain unclear. Increased oxidative stress has been shown to be present in states of hypoxia or cellular stress. Thus, we hypothesize that oxidative stress blockade would ameliorate the increased cell death when exposed to hypoxia.MethodsCardiac stem cells were exposed to hypoxic conditions in cell culture (1% O2 for 24 hours). Oxidative status (by measuring reactive oxygen species‐ROS‐) and cell survival (by the MTT assay) were measured. In a separate group of cells, oxidative stress was blocked using a superoxide dismutase mimetic (Tempol, 1‐10µm/L).ResultsHypoxia resulted in increased expression of the oxidative stress enzyme NAD(P)H oxidase (subfraction 47phox) and in the amount of ROS (increased in the conversion of dihydroethidium ‐DHE‐ and dichlorofluorescein ‐DCF‐) what led to a decrease in stem cell viability. Pre‐conditioning of stem cells with antioxidants (Tempol) decreased the amount of cellular ROS and improved stem cell survival. The increased expression of NAD(P)H p47phox seen in hypoxia was unaltered by oxidative stress blockade.ConclusionIncreased oxidative stress plays a role in the early cell death after hypoxia. Understanding of the mechanisms underlying the fate of stem cells will be critical for the advancement of the field of stem cell therapy.
Unmasking a role for nitric oxide in acetylcholine‐induced vasodilation in diseased human coronary arterioles.
Authors: Wittenburg April Lee , Mendoza Suelhem A , Zhang David X , Gutterman David D 
Published: June 2021

BackgroundAcetylcholine (ACH) dose‐dependently constricts human coronary atrial arterioles (HCA) but dilates ventricular arterioles in patients with coronary disease. Whether NO mechanisms participate in Ach‐induced dilation in atrial arterioles remains unclear. Since CAD and its risk factors generate ROS that can quench NO, we hypothesized that acetylcholine‐induced dilation can be restored in HCA by restoring redox balance and supporting exogenous NO synthesis.MethodsArterioles (~150 μm) from patients with coronary artery disease were prepared for videomicroscopy. HCA's were pre‐incubated with indomethacin (10‐5), sepiapterin (10‐4), L‐Arginine (10‐3), and Peg‐SOD (300units/ml) for 30 minutes. After preconstruction with endothelin‐1, vasomotor responses to exogenous ACH (10‐9 to 10‐4 M) were evaluated in control or in the presence and absence of N‐nitro‐L‐arginine methyl ester (L‐name; 10‐4)).ResultsACH dilated pretreated compared to control intact arterioles [%max dilation (MD): 80±8% vs. ‐36.4±7%]. Treatment with L‐name abolished dilation (MD:‐0.5±9%).ConclusionsReducing endogenous oxidative stress and providing NOS substrate converts an , ACH‐induced constriction to an NO ‐dependent vasodilation in HCA. There may be a greater sensitivity to ROS in endothelium of atrial vs. ventricular arterioles.
IL‐10 suppresses pro‐fibrotic and matrix remodeling genes in normal and myxomatous mitral valves
Authors: Hagler Michael A , Roos Carolyn M , Hadley Thomas A , Schaff Hartzell V , Suri Rakesh M , Miller Jordan D 
Published: June 2021

Myxomatous mitral valve disease (MMVD) is associated with increases in valvular fibrosis, matrix remodeling, and transforming growth factor beta (TGF β) signaling. While interleukin 10 (IL‐10) can suppress tissue fibrosis and matrix metalloproteinase (MMP) expression, its role in MMVD is unknown. We tested the hypotheses that reduced IL‐10 expression contributes to increased tissue fibrosis in MMVD, and that IL‐10 tonically suppresses TGF‐β signaling in normal mitral valves. We used qRT‐PCR to measure expression of IL10, TGF‐β1, MMP 2 and 9, and connective tissue growth factor (CTGF) in normal and myxomatous human mitral valves and in mitral and tricuspid valves from wild‐type and IL‐10 knockout mice. IL‐10 expression was significantly reduced in human myxomatous valves compared to normal valves (53± 12%), and was associated with increases in TGFβ, CTGF, and MMP2. Mitral valve gene expression patterns in IL‐10−/− mice favored fibrosis and matrix remodeling compared to wild‐type littermates, with increases in TGF β (132±7%), CTGF (154±3%), and MMP9 (259±7%) (p< 0.05 for all), but not MMP2. Interestingly, expression of these genes was not altered in tricuspid valves from IL‐10−/− mice. Collectively, these data are the first to show that IL‐10 tonically suppresses TGF β signaling in normal mitral valves and that deficiency of IL‐10 is likely to contribute to fibrosis and matrix remodeling in MMVD.NHLBI
Ozone Exposure Induces Beta‐Adrenergic Insensitivity
Authors: Abston Eric , Fairweather DeLisa 
Published: June 2021

The association between ambient ozone (O3) and adverse cardiopulmonary outcomes has long been recognized. Acute O3 classically induces bradycardia, hypotension, and increases heart rate variability – all of which are affected by the heart's response to sympathetic output. To test whether O3 exposure changes the sensitivity of the heart to beta adrenergic stimulus, C57BL/6 mice (n=10) were exposed to either Room Air (RA) 24 hours of 0.3 ppm O3 and then underwent in‐vivo hemodynamic assessment and isoproterenol (Iso) challenge involving I.V. bolus doses at half log intervals. Mice exposed to O3 displayed decreased left ventricular systolic function as characterized by decreased heart rate 565 bpm vs. 595 bmp in RA; systolic pressure decreased from 106 mmHg in RA mice to 87 mmHg in O3 exposed mice; dP/dT max decreased 10% with O3 exposure. Diastolic function was also depressed by O3 exposure: dP/dT min increased by 25% and Tau (Log) increased by 30% with O3 exposure. O3 exposure resulted in a decreased response to Iso as indicated by a leftward shift in the dose‐response curve. At the maximal dose (6 ng Iso in 10 μL PBS) heart rate increased by 60 bpm in RA controls and 35 bpm in O3 treated mice; dP/dT max increased by 6000 mmHg/s in control and only increased by 3000 mmHg/s in O3 exposed mice. In addition to confirming the systolic and diastolic dysfunction typically associated with O3, this study demonstrates that acute O3 exposure induces beta adrenergic insensitivity – a condition thought to contribute to heart failure in patients with heart disease that may be important in understanding the deleterious cardiopulmonary effects of inhaled O3.NIH R01 HL087033
An Unusual Presentation of Ischemic Stroke as Brain Mass lesion
Authors: Dabi Alok , Kurukumbi Mohankumar , Adams Alice , Jayam‐Trouth Annapurni 
Published: June 2021

BackgroundIschemic stroke is one of the common neurological disorders; however, its presentation as a brain mass lesion is rare.Case Presentation45 year gentleman of Afro‐American origin presented with complaints of right sided weakness, progressing over at least 3 weeks prior to admission. He was found to have no risk factors for stroke except history of substance abuse. He had right sided weakness involving face, and upper limbs more than lower limbs on exam. MRI with gadolinium of the brain revealed a moderately large left fronto‐parietal lesion that showed cortical enhancement. The primary differential was a neoplastic lesion. The patient's clinical condition was progressively worsening, and a brain biopsy was performed. He was simultaneously investigated for primary malignancy elsewhere in the body but had a negative workup. Brain biopsy was reported as ischemic tissue necrosis with no evidence of neoplasm/vasculitis. His course was complicated by development of subdural hematoma after initiation of oral anti‐coagulation for his ischemic stroke. He responded well to surgical evacuation of the hematoma.ConclusionThis rare presentation of a stroke as brain mass lesion signifies the importance of being vigilant about such a possibility. This case is reported for the rarity of its presentation and its impact on the diagnostic and therapeutic management strategies.
The Accuracy of Intraoperative Frozen‐Section Diagnosis in Clinical Staging of Endometrial Carcinomas According to the AJCC 7th Edition Guidelines
Authors: ZULFIQAR MUHAMMAD IMRAN , AHMED YASIN , SHAHAB ASIF , TASHJIAN RANDY , MAZZARA PAUL 
Published: June 2021

IntroductionEndometrial carcinoma is the most common invasive cancer of the female genital tract accounting for 6% of all invasive cancers in women. The prognosis and surgical staging depends on the histologic grade, depth of myometrial invasion and cervical involvement. Surgical staging consists of total abdominal hysterectomy, bilateral salpingo‐oophorectomy, peritoneal cytology, and pelvic lymphadenectomy. Intraoperative frozen section analysis followed by formalin fixed permanent section analysis is used for surgical staging. We compared the accuracy of frozen section staging with the accuracy of permanent section staging.MethodsA retrospective analysis was performed on 46 consecutive patients with endometrial carcinoma between February 2005 and June 2010 at St. John Hospital and Medical Center in Detroit, Michigan. Frozen section staging was performed on all the cases followed by permanent section staging using the AJCC 7th edition staging manual.ResultsComparison between frozen section and permanent section examination did not show a significant difference in the depth of myometrial invasion (p = 0.7). A greater difference was observed with respect to cervical involvement, but this finding was not statistically significant (p = 0.2).ConclusionAlthough sampling of the specimen at frozen section has its limitations, the stage rendered through intraoperative examination generally correlates well with the pathologic stage reported upon permanent section examination.
Methamphetamine exposure affects α‐synuclein expression in the cortex
Authors: Gamble‐George Joyonna Carrie , Khoshbouei Habibeh 
Published: June 2021

Methamphetamine (METH) is a highly addictive psychostimulant that is becoming a global public health problem. Previous studies have suggested that METH exposure is neurotoxic that may induce long‐lasting cognitive and motor impairments after cessation of drug use. α‐synuclein is implicated in neurodegenerative diseases. In this study, we propose that METH exposure affects the levels of α‐synuclein in the brain. Few studies have investigated the molecular mechanism of METH modulation of α‐synuclein in the brain. The present study sought to examine the effect of METH exposure via intraperitoneal injection (24 mg/kg/day) and an osmotic pump (1 mg/kg/hr) on α‐synuclein levels in the brains of juvenile C57BL/6J mice. We found that juvenile mice treated with METH for two weeks via osmotic pump showed an increase in α‐synuclein levels compared to saline‐treated control mice. This increase in α‐synuclein levels may be accountable for METH‐induced neurotoxicity. Since overexpression of α‐synuclein has been implicated in the dysregulation of DA homeostasis, we propose that METH‐induced α‐synuclein changes are dependent upon the pattern of METH administration. Currently, we are examining whether a correlation exists between alterations in α‐synuclein levels and additional molecular targets involved in DAergic homeostasis in the brain that are induced by METH exposure.This research was supported by NIH Grants U54NS041071, U54RR026140, DA026947, and DA021471.
Functional selectivity of brain Gα‐subunit proteins in the cardiovascular and renal excretory responses evoked by central α2‐adrenoceptor activation in vivo
Authors: Wainford Richard David , Kapusta Daniel R 
Published: June 2021

HypothesisBrain Gα‐subunit proteins signal in a functionally selective manner to mediate the integrated cardiovascular depressor and renal excretory responses evoked by pharmacological activation of central α2‐adrenoceptors in vivo.MethodsThe α2‐agonist guanabenz (50 μg) was administered by intracerebroventricular (i.c.v.) injection to conscious instrumented Sprague‐Dawley rats pre‐treated (24‐h) i.c.v. with saline or oligodeoxynucleotides (ODN) targeted to Gαi1,Gi2, Gi3, Gαo, Gαq, Gαz or a scrambled (S) sequence (25 μg, 24‐h, N=5/group). Mean arterial pressure (MAP) and heart rate (HR) were recorded and was urine collected for 150‐min (10‐min periods).Results

i.c.v. ODN pre‐ treatment (24h; 5 μg)
Peak Δ HR (bpm)
Peak Δ MAP (mmHg)
Peak Δ urine output (μl/min)
Peak Δ UNaV (μeq/min)

Saline Vehicle
−92 ± 9
−19 ± 2
+136 ± 9
+6.2 ± 0.8

S
−94 ± 12
−18 ± 1.2
+132 ± 11
+5.9 ± 0.6

Gαi1
−88 ± 11
−19 ± 2
+153 ± 16
+6.1 ± 0.8

Gαi2
−90 ± 13
−1 ± 1**
+125 ± 11
+0.6 ± 0.3**

Gαi3
−66 ± 9
−17 ± 1.3
+143 ± 16
+6.2 ±0.9

Gαo
−47 ± 5*
−16 ± 1.6
+127 ± 10
+6.2 ± 0.5

Gαq
−106 ± 7
−15 ± 2
+214 ± 7**
+7.2 ± 1.2

Gαz
−92 ± 8
−16 ± 2
+110 ± 6*
+5.8 ± 1.2

p<0.05,
p<0.01 vs. S ODN group

Brain Gαi2 subunit protein‐gated signal‐transduction pathways selectively mediate the hypotensive and natriuretic, but not bradycardic or diuretic, responses evoked by central α2‐adrenoceptor activation in vivo. In contrast, the profound α2‐agoinst‐stimulated diuretic response is mediated, in part, via opposing Gαz and Gαq subunit protein gated pathways (stimulatory versus inhibitory, respectively).ConclusionsThese studies demonstrate that in vivo, brain GPCR Gα‐subunit protein pathways play an essential and physiologically important gating role in mediating functionally selective changes in systemic cardiovascular function and the renal excretion of water and sodium post‐ligand binding at central α2‐adrenoceptors. RDW‐AHA 2250585; DRK‐DK43337, HL071212, AHA 0855293E, and RDW/DRK‐ P20 RR018766
Thrombin stimulated glioblastoma cell proliferation is mediated by RhoA and phospholipase D dependent Rap1 activation
Authors: Sayyah Jacqueline , Nogal Nekeisha , Dusaban Stephanie 
Published: June 2021

We previously reported that stimulation of PAR1 receptors with thrombin activates RhoA and induces mitogenesis in 1321N1 glioblastoma cells. Signaling through RhoA is known to be required for cell transformation by Ras. Another Ras family GTPase, Rap1, plays an important role in cancer and constitutive activation of Rap‐GEFs are associated with aberrant cell growth. Accordingly we asked whether stimulation of PAR1 receptors with thrombin elicits Rap1 activation in 1321N1 cells. We found that thrombin induces a robust and sustained (up to 6 hours) increase in Rap1 activation that is dependent on RhoA signaling. Since RhoA is known to activate phospholipase D (PLD) and diacyclglycerol generated via PLD metabolism can activate GEFs that regulate Rap1 activity, we hypothesized that PLD is a mediator of thrombin‐induced Rap1 activation. Inhibition of the PLD pathway by 1‐butanol and FIPI attenuated thrombin‐induced Rap1 activation and downstream ERK1/2 signaling in 1321N1 cells, indicating that PLD is required for thrombin stimulated Rap1 and ERK1/2 activation. Moreover, blockade of Rap1 activity in these cells significantly suppressed thrombin induced ERK1/2 phosphorylation and cell proliferation. Collectively, our results suggest that PLD is an upstream mediator of thrombin elicited Rap1 activation and that Rap1 signaling is required for mitogenesis in glioblastoma cells.(NIH T32 AG000216‐16 grant)
Increased contractility in transgenic mice with overexpression of the targeting subunit B56a of PP2A
Authors: Kirchhefer Uwe , Boknik P. , Heinick A. , Kucerova D. , Neumann J. , Schmitz W. , Stümpel F. , Müller F. U. 
Published: June 2021

Protein phosphatase (PP2A) is a heterotrimeric protein consisting of a catalytic (C), a scaffolding (A), and a regulatory (B) subunit. The B subunit anchors the C subunit to subcellular locations and therefore defines, at least in part, substrate specificity. To reveal new insights in the regulation of the main cardiac B subunit, we generated transgenic mice with heart‐directed overexpression of human B56α under the control of the α‐MHC promoter (TG). TG hearts exhibited a 2‐fold overexpression of B56α compared to wild‐type (WT) mice. This was associated with a 2‐fold higher protein expression of C (n=5, P<0.05). Consistently, total phosphorylase a‐PP activity was increased by 25% in TG (n=5, P<0.05). Overexpression of B56α reduced the efficacy of PP2A inhibition by okadaic acid (OA), a PP2A selective PP inhibitor, at low concentrations. The application of 0.3 nmol/L OA decreased total PP activity by 18% and 33% in TG and WT, respectively (n=5, P<0.05). The protein expression of Aα remained unchanged between TG and WT, as observed for PP1‐C. Force of contraction was increased after application of 10 μmol/L isoproterenol by 63% in TG compared to WT isolated left atria (n=6, P<0.05). We conclude that overexpression of B56α led to a higher contractility in TG after β‐adrenergic stimulation. Thus, our data suggest a critical role of PP2A targeting by B56α in the regulation of cardiac contractile function.This study was supported by the DFG and the IMF Münster.
Activation of Ca‐dependent Potassium Channels Improves Impaired EDHF Signaling in Uterine Arteries during Diabetic Pregnancy
Authors: Gokina Natalia I , Bonev Adrian , Gokin Alexander , Phillips Julie 
Published: June 2021

Diabetic pregnancy is associated with adverse fetal complications in part due to impaired uteroplacental blood flow. In this study we define: (1) diabetes‐induced changes in uterine arterial responses to ACh and NS309; (2) the effect of NS309 on EDHF‐mediated dilatation; and (3) the dependence of this effect on changes in endothelial cell (EC) [Ca2+]i.Diabetes was induced in rats by i.p. injection of streptozotocin (STZ) on day 2 of pregnancy. NS309 and ACh were tested in uterine arteries pre‐constricted with phenylephrine (PE). A subset of the vessels was pre‐treated with 1 μM NS309 before PE and ACh application. [Ca2+]i responses were studied using fura‐2. MP was recorded with glass microelectrodes. Apamin and charybdotoxin (CTX) were tested in single SMCs.NS309‐induced dilatation, hyperpolarization and [Ca2+]i were reduced in diabetes. SMC K+ currents were insensitive to apamin and CTX. Vasodilation to ACh was impaired in diabetes (22 ± 8 % vs. 78 ± 6 % in controls at 1 μM ACh), but was markedly enhanced with 1 μM NS309 (75 ± 6 %). NS309 produced no significant changes in ACh‐induced EC [Ca2+]i responses.Impaired EDHF‐dependent dilatation in diabetes can be markedly enhanced by activation of endothelial SKCa/IKCa channels without changes in EC [Ca2+]i. Openers of these channels may serve as a pharmacotherapy for improvement of maternal uteroplacental blood flow in diabetic pregnancies.Supported by NIH HL088245
Interaction of RAGE with focal adhesion molecules during alveolar epithelial‐mesenchymal transition
Authors: Ehrhardt Carsten , Medina Carlos , Buckley Stephen Timothy 
Published: June 2021

Ezrin/radixin/moesin (ERM) proteins provide a linkage between F‐actin and membrane proteins. RAGE also associates with components of the cytoskeleton. This study tested the hypothesis that RAGE‐ERM interaction plays a role in regulating EMT‐associated structural changes in alveolar epithelial cells.A549 cells were stimulated with TGF‐β1 for 72 h. The interaction of ERM proteins and F‐actin was investigated by immunofluorescence microscopy (IFM) and Western blot (WB). RAGE and sRAGE expression and localisation was determined by WB and IFM. MMP‐9 activity was evaluated using gelatin zymography. Co‐immunoprecipitation studies and IFM was performed to assess the association of ERM and RAGE, and ERM and CD44.Exposure to TGF‐β1 gave rise to re‐distribution of ERM to the cell periphery and co‐localisation with EMT‐associated actin stress fibres. Concurrently, ERM underwent phosphorylation. Expression of RAGE was diminished, coupled with release of its soluble isoform (sRAGE) in a MMP‐9 dependent manner. IFM and co‐IP identified strong association between ERM and RAGE under basal conditions, which was disrupted when challenged with TGF‐β1, with pERM forming a complex with membrane‐linked CD44.These data indicates that disruption of the ERM‐RAGE complex may be a crucial step in actin microfilament re‐arrangement during cytokine‐induced EMT of human alveolar epithelial cells.
Biomechanical analysis of the human head‐neck‐shoulder complex: Asymmetry as a natural experiment
Authors: Osborn Michelle L. , Homberger Dominique G. 
Published: June 2021

The unique human mastoid processes and clavicles are a consequence of the shoulder girdle being suspended from the skull. When one arm is used, the upper trapezius and sternocleidomastoid muscles contract to counterbalance the added weight on that shoulder. Core muscles acting on the atlanto‐occipital and cervical joints synchronously contract to prevent retroflexion of the head. Our hypothesis was tested by a natural experiment based on the asymmetry of biomechanically relevant paired skeletal features in right‐handed males. Our biomechanical free‐body diagram analyses show that asymmetrical muscle forces act on the mastoid processes, skull, and clavicles when one arm is favored and predict that these forces, over time, stimulate different bone growth at their attachment sites. Quantitatively, our data show that at least 70% of the individuals had a wider right and a longer left mastoid process; a higher and/or more robust right superior nuchal line; a broader left scapula; and/or a greater right humerus diameter. Qualitatively, however, each individual displayed a unique combination of at least two of these features indicative of right‐handedness. Individual differences are probably caused by long‐term force regimes due to idiosyncratic movements and athletic or professional activities.Funding: LSU Robert C. West Fund to MLO; LSU Foundation to DGHGrant Funding Source: LSU Foundation
Characterization of a trinitrobenzene sulphonic acid (TNBS)‐induced mouse model of Periodontitis
Authors: San Miguel Symone M. , Tillberg Connie M. , Opperman Lynne A. , Svoboda Kathy K.H. 
Published: June 2021

The 2,4,6‐trinitrobenzenesulfonic acid (TNBS)‐murine model has been used for immunopathogenesis of inflammatory bowel disease. The use of TNBS induces severe colonic inflammation when administered intrarectally in mice. The colitis which results from this procedure also presents clinical and histopathological findings common in periodontitis. This study will characterize parameters needed for successful induction of TNBS‐colitis as well as monitoring periodontal disease levels among 20 adult CD1 mice. The experimental groups were given 25 μL gingival injections of TNBS and the sham groups were given 25 μL saline solution (0.9% NaCl) in each quadrant of both maxillary and mandibular arches. Each group received 50 μL of TNBS or saline solution orally thrice weekly and was given both a gel diet in addition to solid mouse pellets. Oral and systemic tissue samples were collected at 2, 4, 6, 10 weeks. Radiographic examinations of both arches were taken to supplement histologic evaluations of changes in tooth supporting structures. Soft tissue samples were obtained from the large intestines and analyzed for the extent of systemic inflammation caused by TNBS. Colitis was present from second week on, with TNBS treatment. Radiographic and histochemical analyses revealed some changes in the alveolar bone pattern. Morphologic changes were noted in the colonic mucosa with extensive inflammatory infiltrates and some ulceration. This novel approach can help elucidate the relationship between alveolar bone loss and systemic manifestation common to gingival and periodontal disease for future therapeutic purposes.Grant Funding Source: PerioSciences, LLC