bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early‐phase cerebral arteriogenesis: Evidence of endothelial activation, vascular proliferation and local inflammation
Authors: Bondke Anja , Hillmeister Philipp , Duelsner André , Gruber Clemens , Buschmann Ivo R. , Lehmann Kerstin 
Published: June 2021

Arteriogenesis holds potential as a novel treatment for ischemic vascular disease. Our study aimed at an identification of key processes of early‐phase cerebral arteriogenesis in vivo.In a rat model of nonischemic cerebral hypoperfusion the posterior cerebral artery (PCA) constitutes a main collateral to the contralateral hemisphere. Following reversed flow, endothelial cell (EC) activation was assessed by electron microscopy. Gene expression during biomechanical EC activation was analyzed by cDNA microarray. Proarteriogenic vascular proliferation and local inflammation were evaluated.PCA diameters increase significantly(+30%). Ultrastructural EC activation occurs at 3d postoperatively, followed by CD68+ cellular transmigration and sustained vessel wall proliferation. Of 164 genes deregulated, 48 contain shear stress response elements (SSREs) or NFkB binding sites in their promoter regions. Arteriogenesis leads to NFkB activation as shown by local NFkB p65 expression.Cerebral arteriogenesis is initiated by EC activation through changed blood flow, facilitating monocyte influx and collateral proliferation. Gene expression is modified by biomechanical activation via SSREs and the pro‐inflammatory environment (NFkB activation, monocyte influx). Therapeutic arteriogenesis may aim at 1) biomechanical EC activation 2)vascular proliferation or 3)local monocyte function.
Inhibition of inducible nitric oxide synthase attenuates platelet activation and fibrinogen/fibrin deposition in pulmonary microvessels caused by lung ischemia‐reperfusion in rabbits
Authors: Roberts Andrew M. , Perez‐Abadia Gustavo , Conhaim Robert L. , Lominadze David 
Published: June 2021

We previously showed that lung ischemia‐reperfusion (IR) causes platelet adhesion and pulmonary microvascular constriction. Experiments were done to examine the role of platelet activation and fibrinogen/fibrin (Fg/Fb) deposition in vascular dysfunction during pulmonary IR. In anesthetized rabbits with open chest, we ventilated the lungs and examined subpleural microvessels in the right lung by video microscopy during brief periods when the lungs were statically inflated (10 cm H2O). IR was caused by placing a removable clip on the right pulmonary artery for 2 h. During reperfusion, we injected albumin labeled with fluorescein (green) and a fluorescently labeled (red) polyclonal antibody to Fg/Fb, via the right atrium. Enhanced platelet adhesion and Fg/Fb deposition were found during IR and were associated with sites of albumin leakage. These effects were attenuated by infusion of an iNOS activity inhibitor (1400W) before IR. Confocal microscopy of tissue samples confirmed associations between platelets, Fg/Fb, and albumin leakage. Our data suggest that platelet activation and Fb/Fg deposition are associated with elevated iNOS activity and may be a cause of microvascular dysfunction during lung IR.Supported in part by The American Lung Association‐Kentucky to AMR and by NIH grant# HL080394 to DL.
MEF2C Silencing Attenuates Load‐Induced Hypertrophy and Energetic Metabolism in Mice Left Ventricle
Authors: Pereira Ana Helena M , Clemente Carolina F.M.Z. , Theizen Thais H , Rocco Silvana A , Souza Jose R.M. , Pascoal Vinicius D.B. , Lopes‐Cendes Iscia , Franchini Kleber G 
Published: June 2021

Aim: Myocyte enhancer factor 2C (MEF2C) transcription factor has been suspected to play a critical role in coordinating the proper response of cardiac myocytes to hypertrophic stimuli. However, a better understanding of the role of MEF2C in cardiac hypertrophy has been hampered by the fact the loss‐of‐function models of MEF2C in the heart do not survive to adult life. In the present study, we used an interference RNA strategy to investigate the role of MEF2C in the hypertrophic growth induced by pressure overload in mice left ventricle (LV).Methods: siRNA targeted to MEF2C was delivery (30 μg) through the jugular vein of mice in the day before the surgery to establish transverse aortic constriction (TAC).Results: siRNA administration induced prolonged MEF2C silencing (70 to 50% up to 15 days) in both control and TAC mice. MEF2C silencing was also confirmed in myocytes harvested from LV. Myocardial MEF2C silencing was accompanied by a marked attenuation of left ventricular hypertrophy and in the increases of the hypertrophic marker β‐myosin heavy chain but it did not affect the typical myocardial fibrosis of TAC mice. Furthermore, we observed no significant change in LV diameter or fractional shortening in TAC mice treated with siRNA targeted to MEF2C, despite the lack of increase in LV wall thickness in response to pressure overload. MEF2C silencing was also demonstrated to be accompanied by an increase in the AMP:ATP ratio in overloaded LV possibly reflecting the lack of proper mitochondrial biogenesis.Conclusion: These findings suggest that MEF2C modulates multiple aspects of cardiac hypertrophy induced by mechanical stress, including the expression of sarcomeric genes and the changes in the energetic metabolism.
Caloxin 1c2: Experimental Evidence That It Binds Plasma Membrane Calcium Pump
Authors: Pande Jyoti , Szewczyk Magdalena M , Kuner Rajneet , Ghosh Paromita , Grover Ashok K 
Published: June 2021

We engineered caloxin 1c2, a novel high affinity peptide (TAWSEVLDLLRRGGGSK‐amide) inhibitor of the Plasma Membrane Ca2+ pump (PMCA). To show that caloxin 1c2 acts by binding to the PMCA, we synthesized a photoreactive derivative 3Bpa‐caloxin 1c2 (TA(Bpa)SEVLDLLRRGGGSK‐biotin), containing the photoreactive residue Bpa (benzoylphenylalanine) and biotin. 3Bpa‐caloxin 1c2 inhibited the Ca2+‐Mg2+‐ATPase activity of PMCA. The human erythrocyte membranes were photolabeled with 3Bpa‐caloxin 1c2 and the proteins were detected in the Western blots using HRP‐streptavidin to identify biotin or PMCA antibodies to detect PMCA. The photolabeled erythrocyte membranes showed a 250–270 kDa doublet with HRP‐streptavidin. The degree of biotinylation of the erythrocyte membranes depended on the length of the cross‐linking time, and concentrations of 3Bpa‐caloxin 1c2 and the membrane protein. Immunoprecipitates from the photolabeled erythrocyte membranes using a PMCA antibody showed a 250–270 kDa doublet with HRP‐streptavidin. Biotinylated proteins isolated from the photolabeled erythrocyte membranes using captavidin also showed a 250–270 kDa doublet with HRP‐streptavidin and PMCA antibodies. Caloxin 1c2 had been selected for binding to the extracellular domain 1 (amino acids 115–131) of PMCA isoform 4. Caloxin 1c2 and the extracellular domain 1 peptide of PMCA 4 competed with 3Bpa‐caloxin 1c2 for photolabeling the erythrocyte membranes. Pieces of de‐endothelialized pig coronary artery cross‐linked to 3Bpa‐caloxin 1c2 and treated with Alexa‐streptavidin were examined by confocal microscopy, using the Na+‐pump inhibitor Bodipy‐ouabain as a positive control. Both the probes bound to the cell surface. Thus, the photoreactive derivative of caloxin 1c2 binds to PMCA at the cell surface.Supported by Heart & Stroke Foundation of Ontario.
Latent Fluorophores for Biomolecular Imaging
Authors: Raines Ronald T. 
Published: June 2021

Ribonucleases can be cytotoxic because cleaving RNA renders indecipherable its encoded information. We have shown that, with the subtlest of manipulation, an otherwise innocuous ribonuclease can be transformed into a useful cytotoxin. Bovine pancreatic ribonuclease (RNase A) is the most often studied enzyme. We reasoned that this nontoxic enzyme could become cytotoxic if it were able to evade the endogenous ribonuclease inhibitor protein that protects cellular RNA against invading ribonucleases. By changing a single amino acid residue, we made RNase A toxic to human cells, thereby verifying our hypothesis. We have extended this approach to RNase 1, which is the human homologue of RNase A. Most importantly, we have shown that the cytotoxicity of these enzymes is manifested preferentially against cancer cells, both in vitro and in vivo. A variant of RNase 1 is scheduled to enter a Phase I clinical trial as a cancer chemotherapeutic in early 2008. We are now using a variety of tools, especially new small‐molecule probes known as “latent fluorophores” to delineate the mechanism by which our cytotoxic ribonucleases kill human cancer cells.This work is supported by Grant CA73808 (NIH).
Target specified preautonomic neurones in the PVN receive a GABAergic input
Authors: Pyner Susan , Watkins Nicholas David 
Published: June 2021

The paraventricular nucleus of the hypothalamus (PVN) maintains cardiovascular homeostasis. Evidence suggests that within the PVN, GABA and nitric oxide (NO) determine the level of excitability of presympathetic neurones and that an alteration of their action may lead to the sympatho‐excitation evident in heart failure. Anatomically, there is sparse evidence indicating how GABAergic and NO producing neurones might regulate presympathetic neurones. Therefore, the purpose of this study was to identify the location of GABAergic neurones in the PVN in relation two groups of target specified presympathetic neurones that play a role in cardiovascular homeostasis. Male Wistar rats had Fluorogold (FG) injected into the T2 region of the spinal cord. In a further group (male Sprague Dawley) herpes simplex virus expressing green fluorescent protein (HSV‐1‐GFP) was injected into the adrenal medulla (AM) or superior cervical ganglion (SCG). After a suitable survival period, brain tissue was processed to localise FG, HSV‐1‐GFP and GABA. AM and SCG presympathetic neurones were present in the parvocellular nuclei of the PVN. GABAeregic neurones surrounded the lateral boundaries of the dorsal cap. A minority of GABAergic neurones contained HSV‐1‐GFP while no FG neurone was found to be GABAergic. We suggest target specified presympathetic neurones of the PVN receive a GABAergic input.Supported by British Heart Foundation.
Serotonin (5‐HT) facilitates ventilation via distinct 5HT2 and 5HT4 receptor‐mediated mechanisms in situ, in the arterially perfused rat brainstem preparation
Authors: Corcoran Andrea E , Richerson George B , Harris Michael B 
Published: June 2021

Studies in vitro suggest that serotonin (5HT) neurons may be important for CO2 chemosensitivity. Their roles in modulating breathing in vivo, however, are unclear. We use a perfused in situ rat brainstem preparation that exhibits patterns of phrenic nerve discharge akin to breathing. Neuroventilation (NV) in this preparation is sensitive to the levels of CO2 equilibrating perfusion solutions (ranging between 3.5 and 9% CO2). We have shown that changes in NV associated with mild hypercapnia are abolished by inhibiting 5‐HT neurons. The present study was designed to identify post‐synaptic receptor subtypes involved in the control of breathing, and test the hypothesis that specific serotonergic mechanisms are critical for normal ventilatory control. Treatment with a 5HT2 antagonist (ketanserin; 5 and 10 uM) depresses NV under low CO2 conditions, indicating a 5HT2 mediated facilitation of NV under hypocapnea. Elevating CO2 (3.5 to 7%) reverses ketanserin‐induced NV depression, indicating CO2‐sensitive NV excitation, mediated through a mechanism other than 5HT2 receptor activation. Preliminary results suggest the balance may be due to 5HT4 activation in response to CO2, supporting a role for diverse serotonergic mechanisms in CO2 chemosensitivity in this preparation.Research supported by the NIH, NIMH and NINDS, Office of Minority Health Research SNRP program; grant number 5 U54 NS41069‐06A1
Beneficial effects of sildenafil to alleviate pulmonary hypertension after 2 and 4‐week chronic hypoxia
Authors: Milano Giuseppina , Joncic Ana , Morel Sandrine , Samaja Michele , Vassalli Giuseppe , von Segesser Ludwig Karl 
Published: June 2021

Aim. We investigated whether sildenafil alleviates the cardiovascular and pulmonary alterations induced by 2‐ or 4‐week chronic hypoxia (CH).Methods. Rats were exposed to room air (21% O2, N), CH (10% O2) for 2 and 4 weeks, with and without treatment with Sildenafil (1.4 mg/Kg/day, ip) (n=7/group). At the end of the exposure, we measured right ventricular hypertrophy (right to left plus septum weight, RV/LV+S), pulmonary wall thickness index (WTI), right and left systolic ventricular pressures (RVSP and LVSP, respectively) and endothelial nitric oxide synthase (eNOS) proteins.Results. CH increased RV/LV+S (p<0.05) and WTI (p<0.01) after 2 and 4 weeks. Treatment with sildenafil attenuated both parameters after 2 weeks (p<0.05) and after 4 weeks hypoxia (p=0.01). RVSP was higher in CH than N rats (p=0.01). Treatment with sildenafil attenuated this parameter irrespectively of the duration of hypoxia. By contrast, CH did not change LVSP after either 2 or 4 weeks. The phosphorylated form of eNOS decreased in CH hearts (p<0.05). Treatment with Sildenafil increased the phosphorylated form of eNOS to normoxic values irrespectively of duration of hypoxia.Conclusion. Treatment with sildenafil provides an efficient strategy for the management of cardiac and pulmonary hypertrophy during CH, irrespectively of the duration until 4 weeks, presumably via increased phosphorylation of eNOS.
Superoxide dismutase mimetic tempol inhibits hypoxic pulmonary vasoconstriction in rats independently on either nitric oxide production or basal tone of pulmonary vessels
Authors: Hodyc Daniel , Snorek Michal , Brtnicky Tomas , Herget Jan 
Published: June 2021

Hypoxic pulmonary vasoconstriction (HPV) is regulated by changes in the production of and interactions among reactive oxygen species (ROS). There is a controversy as to whether HPV is mediated by an increase or a decrease in ROS production. Also, the role of nitric oxide (NO) in HPV remains unclear. We investigated whether the inhibition of HPV by the antioxidant tempol was dependent on the concentration of NO, and how its effect was influenced by increased basal pulmonary vascular tone.In isolated rat lungs we measured vasoconstrictor responses to acute hypoxia before and after administration of tempol during perfusion with or without L‐NAME and after increase of basal vascular tone in the perfused lungs by increasing the potassium ion concentration in the perfusate by 15 mmol/l.Administration of tempol significantly decreased vasoconstriction response to acute hypoxic challenge both in controls (89% less) and in L‐NAME group (100% less), the vasoconstrictor response did not differ significantly between these groups. The administration of tempol significantly decreased HPV both in K+ treated (96% less) and in K+ non‐treated group (68% less), the vasoconstrictor response did not differ significantly between these groups.Inhibition of HPV by the SOD mimetic tempol does not depend on either NO production or basal tone of the pulmonary vessels.GACR 305/05/0672, GAUK 7415/2007
Does Dietary Cholesterol Increase Cardiovascular Risk in Exercising People? A Randomized Placebo‐Controlled Trial
Authors: Lee Chang Woock , Gasier Heath G , Chikani Gentle , Riechman Steven E 
Published: June 2021

Background: There is no clear evidence that dietary cholesterol increases cardiovascular risk (CVR), likely due to the lack of control for physical activity. We hypothesized in the presence of a standardized exercise program that varying dietary cholesterol would not change CVR. Methods: 3 groups of 50–69 year old subjects (N=30) underwent 12 weeks of resistance exercise training (RET, 3×/week, 2–3 sets, 8–12 reps, 70% of max strength). Each group consumed 3.5 mg/kg lean/day (<200 mg/day, LC), 7.0 mg/kg lean/day (∼400 mg/day, MC), or 14.0 mg/kg lean/day (∼800 mg/day, HC) of cholesterol. Results: No significant differences were found among 3 groups in regard to changes of blood cholesterol (mg/dl, LC: −1.9±15, MC: 4.7±38, HC: 5.9±12, P=.784), HDL (LC: 0.8±2, MC: −0.2±7, HC: 2.1±6, P=.684), LDL (LC: −0.4±13, MC: 12.9±23, HC: 7.5±11, P=.247), triglycerides (LC:−11.8±16, MC:7.6±41, HC:−10±47, P=.479), cholesterol/HDL ratio (LC: −0.08±0.3, MC: 0.08±0.9, HC: −0.02±0.4, P=.846), and systolic/diastolic blood pressures (mmHg, LC: 1.1±5, MC: −2.1±6, HC: −2.1±6, P=.340 / LC: −0.8±4, MC: 0.03±4, HC: 0.1±5, P=.859). Conclusion: The results suggest that variability of dietary cholesterol may not increase CVR in the context of RET which is supported by the weak link of dietary cholesterol to CVR in studies that did not control physical activity.This study was supported by US Poultry and Egg Association
Eucapnic intermittent hypoxia increases Rho kinase‐independent myofilament Ca2+ sensitization in small pulmonary arteries
Authors: Snow Jessica , Kanagy Nancy , Walker Benjimen , Resta Thomas 
Published: June 2021

Intermittent hypoxia (IH) associated with sleep apnea increases circulating concentrations of the vasoconstrictor peptide, endothelin‐1 (ET‐1), and elicits pulmonary hypertension. We hypothesized that, similar to chronic sustained hypoxia, eucapnic IH (E‐IH) enhances pulmonary vasoconstrictor reactivity to ET‐1 through Rho kinase (ROK)‐mediated vascular smooth muscle (VSM) Ca2+ sensitization. To test this hypothesis, we assessed vasoconstrictor responses to ET‐1 (10−11–10−7 M) in the presence or absence of the ROK inhibitor fasudil (10 μM) in endothelium‐disrupted, pressurized pulmonary arteries (158 ± 10 μ m inner diameter) from E‐IH rats (3 min cycles of 5% O2, 5% CO2/air flush, 7 hr/day, 4 wk) or air controls (air/air cycling for equal duration). VSM was loaded with fura‐2 AM to assess changes in VSM intracellular Ca2+ ([Ca2+]i) associated with ET‐1‐induced vasoconstrictor responses. Consistent with our hypothesis, E‐IH augmented ET‐1‐induced vasoconstrictor reactivity (10−9–10−7.5 M) without changing VSM [Ca2+]i responses. Surprisingly, ROK inhibition did not alter vasoconstriction or VSM [Ca2+]i responses in either group. We conclude that E‐IH enhances ET‐1‐induced Ca2+ sensitization in pulmonary VSM through a ROK‐independent mechanism.(Supported by NIH grants HL‐07736, HL‐77876, HL‐58124 and HL‐63207)
Structural damage to erythrocyte‐membrane proteins induced by Lonomia obliqua caterpillar bristle extract
Authors: Seibert Carla Simone , Tambourgi Denise V. , Santoro Marcelo L. , Sampaio‐Verssoni Sandra C , Takahashi Hilton K. , Peres Carmem M. , Sano‐Martins Ida S. 
Published: June 2021

Lonomia obliqua caterpillar bristle extract shows in vitro hemolytic activity in human and rat erythrocytes (Er), and potent intravascular hemolytic activity in rats. Hemostatic disturbances are characteristic in human envenomation, and intravascular hemolysis have been observed in some cases.ObjectiveTo investigate the mechanism whereby L. obliqua caterpillar bristle extract cause lysis of human Er.MethodsHuman Er were treated with sublytic concentrations (250, 500 and 1000 μg/ml) of crude extract or saline (control). Afterwards, Er osmotic fragility was determined, and sialoglycoproteins of the Er‐membrane surface (GPA, GPC and band 3) were quantified using flow cytometry. Lipid bilayer composition was determined (fatty acids, triacylglycerols, cholesterol).ResultsResults are expressed as mean± standard deviation (n= 5). Er treated with 1000 μg/ml crude extract increased osmotic fragility (extract H50%= 90.5 ± 2.70, and control H50%= 75.0 ± 1.32 mM NaCl). Sialoglycoproteins were removed from the Er surface (26 % GPC and 23 % band 3). The ions Ca2+ and Mg2+ increased this activity, showing their greatest effect on band 3 (> 50 % removal). Nevertheless, the extract provoked no damage in the Er lipid bilayer organization.ConclusionCrude extract removes Er membrane proteins responsible for its flexibility and malleability, increasing osmotic fragility, and likely inducing hemolysis by rupturing Er when they are in blood stream.FAPESP
Diarylheptanoids contribute to the estrogenic activity of Curcuma comosa.
Authors: Tantrakool Wipawee , Piyachaturawat Pawinee , Suksamrarn Apichart , Arao Yukitomo , Hewitt Sylvia C. , Korach Kenneth S. 
Published: June 2021

Extracts of Curcuma comosa, a plant in the Zingiberaceae family, exert estrogenic activity in in vivo and in vitro assays. Diarylheptanoids, a major component of C. comosa, are estrogenic in rat uterine bioassays, in an estrogen responsive yeast two‐hybrid system, and in MCF‐7 (human breast cancer) cells. This study aims to characterize further the estrogenic activity of C. comosa‐derived diarylheptanoids. HepG2 cells expressing wild type or mutant forms of the mouse estrogen receptor‐α (ERα) and possessing an estrogen responsive reporter plasmid (3XERE‐TATA‐Luc) were exposed to increasing doses of diarylheptanoids. At 50 μM, the diarylheptanoids were equally efficient as 1 nM estradiol at stimulating ERE‐driven reporter activity, and this response was dose‐dependent. This activity was inhibited by the ER antagonist (ICI‐182780). A mutant ERα lacking the AF2 domain was unresponsive to the diarylheptanoids, while ERα lacking the AF1 domain exhibited wild type‐like activity. These data indicate that diarylheptanoids are active in an ER‐dependent system and this activity is dependent on ERα, more specifically its AF2 function. We therefore surmise that diarylheptanoids contribute to the estrogenic activity of C. comosa.Supported by Thailand Research Fund through Royal Golden Jubilee PhD Program (PHD/0255/2546) to WT and PP; BIOTEC grant to AS; NIEHS Division of Intramural Research Funding to WT, YA, SCH and KSK.
Spinal cord hemisection disrupts descending neuregulin input to phrenic motoneurons
Authors: Issa Amine Najib , Zhan When Zhi , Fang Yun‐Hua , Bailey Jeffery P , Sieck Gary C , Mantilla Carlos B 
Published: June 2021

Spinal cord hemisection at C2 (SH) disrupts descending drive to ipsilateral phrenic motoneurons (PMNs) causing unilateral diaphragm muscle (DIAm) paralysis. Previously, we found a decrease in motoneuron size at 2 weeks post‐SH. Recently, we found neuregulin (NRG) in synaptic boutons surrounding PMNs. NRG is a trophic factor known to regulate development of the neuromuscular junction, but the effect of NRG on motoneurons is unknown. We hypothesized that 1) NRG input to PMNs is supraspinal in origin, and 2) SH disrupts NRG input to PMNs. Adult male Sprague‐Dawley rats underwent SH or sham‐surgery. PMNs were retrogradely labeled by intramuscular injection of Alexa488‐conjugated cholera toxin B. Using laser capture microdissection, we found that PMNs express mRNA for the NRG receptors ErbB2 and ErbB3, providing a functional substrate for a NRG effect. Two weeks post‐SH, labeled PMNs and NRG boutons were imaged using confocal microscopy. PMN morphology and the number of NRG boutons in the vicinity of PMNs were determined using a computerized, semi‐automated reconstruction algorithm. NRG boutons were fairly homogeneously distributed on motoneurons independent of size. Following SH, few NRG boutons were observed. We conclude that 1) NRG input to PMNs derives from a supraspinal source; and 2) SH removes NRG input to PMNs. It is possible that NRG input exerts a trophic influence on PMNs.Supported by NIH grants HL37680, AR51173 and Mayo Clinic