scholarly journals Structural, Pro-Inflammatory and Calcium Handling Remodeling Underlies Spontaneous Onset of Paroxysmal Atrial Fibrillation in JDP2-Overexpressing Mice

2020 ◽  
Vol 21 (23) ◽  
pp. 9095
Author(s):  
Mariana S. Parahuleva ◽  
Jens Kockskämper ◽  
Jacqueline Heger ◽  
Wolfram Grimm ◽  
Anna Scherer ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Immune Cell ◽  
Marker Gene ◽  
Fold Increase ◽  
Calcium Handling ◽  
In Vivo Studies ◽  
Western Blots ◽  
The Impact ◽  
Spontaneous Onset

Background: Cardiac-specific JDP2 overexpression provokes ventricular dysfunction and atrial dilatation in mice. We performed in vivo studies on JDP2-overexpressing mice to investigate the impact of JDP2 on the predisposition to spontaneous atrial fibrillation (AF). Methods: JDP2-overexpression was started by withdrawal of a doxycycline diet in 4-week-old mice. The spontaneous onset of AF was documented by ECG within 4 to 5 weeks of JDP2 overexpression. Gene expression was analyzed by real-time RT-PCR and Western blots. Results: In atrial tissue of JDP2 mice, besides the 3.6-fold increase of JDP2 mRNA, no changes could be detected within one week of JDP2 overexpression. Atrial dilatation and hypertrophy, combined with elongated cardiomyocytes and fibrosis, became evident after 5 weeks of JDP2 overexpression. Electrocardiogram (ECG) recordings revealed prolonged PQ-intervals and broadened P-waves and QRS-complexes, as well as AV-blocks and paroxysmal AF. Furthermore, reductions were found in the atrial mRNA and protein level of the calcium-handling proteins NCX, Cav1.2 and RyR2, as well as of connexin40 mRNA. mRNA of the hypertrophic marker gene ANP, pro-inflammatory MCP1, as well as markers of immune cell infiltration (CD68, CD20) were increased in JDP2 mice. Conclusion: JDP2 is an important regulator of atrial calcium and immune homeostasis and is involved in the development of atrial conduction defects and arrhythmogenic substrates preceding paroxysmal AF.

scholarly journals Trends in Managing Cardiac and Orthopaedic Device-Associated Infections by Using Therapeutic Biomaterials

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1556
Author(s):  
Stefania Scialla ◽  
Giorgia Martuscelli ◽  
Francesco Nappi ◽  
Sanjeet Singh Avtaar Singh ◽  
Adelaide Iervolino ◽  
...  
Keyword(s):  
Clinical Medicine ◽  
Preventive Treatment ◽  
Active Surface ◽  
In Vivo Studies ◽  
Antibiotic Resistant ◽  
Implanted Medical Devices ◽  
Hospital Acquired ◽  
Systemic Antibiotics ◽  
The Impact

Over the years, there has been an increasing number of cardiac and orthopaedic implanted medical devices, which has caused an increased incidence of device-associated infections. The surfaces of these indwelling devices are preferred sites for the development of biofilms that are potentially lethal for patients. Device-related infections form a large proportion of hospital-acquired infections and have a bearing on both morbidity and mortality. Treatment of these infections is limited to the use of systemic antibiotics with invasive revision surgeries, which had implications on healthcare burdens. The purpose of this review is to describe the main causes that lead to the onset of infection, highlighting both the biological and clinical pathophysiology. Both passive and active surface treatments have been used in the field of biomaterials to reduce the impact of these infections. This includes the use of antimicrobial peptides and ionic liquids in the preventive treatment of antibiotic-resistant biofilms. Thus far, multiple in vivo studies have shown efficacious effects against the antibiotic-resistant biofilm. However, this has yet to materialize in clinical medicine.

67 Current Status and Future Prospective of the Use of Plant Bioactive Compounds in Dairy and Beef Cattle

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 132-132
Author(s):  
Sergio Calsamiglia ◽  
Maria Rodriguez-Prado ◽  
Gonzalo Fernandez-Turren ◽  
Lorena Castillejos
Keyword(s):  
Beef Cattle ◽  
Essential Oils ◽  
Average Daily Gain ◽  
Rumen Fermentation ◽  
Production Performance ◽  
In Vivo Studies ◽  
Current Status ◽  
The Impact

Abstract In the last 20 years there has been extensive in vitro research on the effects of plant extracts and essential oils on rumen microbial fermentation. The main objectives have been to improve energy metabolism through a reduction in methane emissions and an increase in propionate production; and to improve protein metabolism by reducing proteolysis and deamination. While the positive results from in vitro studies has stimulated the release of commercial products based on blends of essential oils, there is limited in vivo evidence on the rumen fermentation and production performance effects. A literature search was conducted to select in vivo studies where information on rumen fermentation and animal performance was reported. For dairy cattle, we identified 37 studies of which 21 were adequate to test production performance. Ten studies reported increases and 3 decreases in milk yield. For beef cattle, we identified 20 studies with rumen fermentation profile and 22 with performance data. Average daily gain improved in 7 and decreased in 1 study. Only 1 out of 16 studies reported an improvement in feed efficiency. Data indicate that out of more than 500 products tested in vitro, only around 20 have been tested in vivo in different mixtures and doses. The use of statistical approaches will allow to describe the conditions, doses and responses in dairy and beef cattle performance. The search for postruminal effects offers another alternative use. Evidence for effects on the intestinal and systemic effects on the immune system and antioxidant status (i.e., capsicum, garlic, eugenol, cinnamaldehyde curcuma, catechins, anethol or pinene), and in the modulation of metabolic regulation (capsicum, cinnamaldehyde, curcuma or garlic) may open the opportunity for future applications. However, stability of the product in the GI tract, description of the mechanisms of action and the impact of these changes on performance needs to be further demonstrated.

Abstract P780: Myosin Light Chain Dephosphorylation by Ppp1r12c Promotes Atrial Hypocontractility in Atrial Fibrillation

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Francisco J Gonzalez-Gonzalez ◽  
Perike Srikanth ◽  
Andrielle E Capote ◽  
Alsina Katherina M ◽  
Benjamin Levin ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Molecular Mechanisms ◽  
Contractile Function ◽  
Right Atrial ◽  
Western Blots

Atrial fibrillation (AF) is the most common sustained arrhythmia, with an estimated prevalence in the U.S.of 6.1 million. AF increases the risk of a thromboembolic stroke in five-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function in AF remains unknown. We have recently identified protein phosphatase 1 subunit 12c (PPP1R12C) as a key molecule targeting myosin light-chain phosphorylation in AF. Objective: We hypothesize that the overexpression of PPP1R12C causes hypophosphorylation of atrial myosin light-chain 2 (MLC2a), thereby decreasing atrial contractility in AF. Methods and Results: Left and right atrial appendage tissues were isolated from AF patients versus sinus rhythm (SR). To evaluate the role of the PP1c-PPP1R12C interaction in MLC2a de-phosphorylation, we utilized Western blots, co-immunoprecipitation, and phosphorylation assays. In patients with AF, PPP1R12C expression was increased 3.5-fold versus SR controls with an 88% reduction in MLC2a phosphorylation. PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF. In vitro studies of either pharmacologic (BDP5290) or genetic (T560A), PPP1R12C activation demonstrated increased PPP1R12C binding with both PP1c and MLC2a, and dephosphorylation of MLC2a. Additionally, to evaluate the role of PPP1R12C expression in cardiac function, mice with lentiviral cardiac-specific overexpression of PPP1R12C (Lenti-12C) were evaluated for atrial contractility using echocardiography, versus wild-type and Lenti-controls. Lenti-12C mice demonstrated a 150% increase in left atrium size versus controls, with reduced atrial strain and atrial ejection fraction. Also, programmed electrical stimulation was performed to evaluate AF inducibility in vivo. Pacing-induced AF in Lenti-12C mice was significantly higher than controls. Conclusion: The overexpression of PPP1R12C increases PP1c targeting to MLC2a and provokes dephosphorylation, associated with a reduction in atrial contractility and an increase in AF inducibility. All these discoveries suggest that PP1 regulation of sarcomere function at MLC2a is a main regulator of atrial contractility in AF.

Abstract P458: Myosin Light Chain Dephosphorylation By Ppp1r12c Promotes Atrial Hypocontractility In Atrial Fibrillation

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Francisco J Gonzalez-Gonzalez ◽  
Srikanth Perike ◽  
Frederick Damen ◽  
Andrielle Capote ◽  
Katherina M Alsina ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Molecular Mechanisms ◽  
Contractile Function ◽  
Right Atrial ◽  
Western Blots

Introduction: Atrial fibrillation (AF), is the most common sustained arrhythmia, with an estimated prevalence in the U.S. of 2.7 million to 6.1 million and is predictive to increase to 12.1 million in 2030. AF increases the chances of a thromboembolic stroke in five-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function in AF remains unknown. Objective: The overexpression of PPP1R12C, causes hypophosphorylation of atrial myosin light chain 2 (MLC2a), decreasing atrial contractility. Methods and Results: Left and right atrial appendage tissues were isolated from AF patients versus sinus rhythm (SR). To evaluated the role of PP1c-PPP1R12C interaction in MLC2a de-phosphorylation we used Western blots, coimmunoprecipitation, and phosphorylation assays. In patients with AF, PPP1R12C expression was increased 3.5-fold versus SR controls with an 88% reduction in MLC2a phosphorylation. PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF. In vitro studies of either pharmacologic (BDP5290) or genetic (T560A) PPP1R12C activation demonstrated increased PPP1R12C binding with both PP1c and MLC2a, and dephosphorylation of MLC2a. Additionally, to evaluate the role of PPP1R12C expression in cardiac function, mice with lentiviral cardiac-specific overexpression of PPP1R12C (Lenti-12C) were evaluated for atrial contractility using echocardiography, versus wild-type and Lenti-controls. Lenti-12C mice demonstrated a 150% increase in left atrium size versus controls, with reduced atrial strain and atrial ejection fraction. Also, programmed electrical stimulation was performed to evaluate AF inducibility in vivo. Pacing-induced AF in Lenti-12C mice was significantly higher than controls. Conclusion: The Overexpression of PPP1R12C increases PP1c targeting to MLC2a and provokes dephosphorylation, that cause a reduction in atrial contractility and increases AF inducibility. All these discoveries advocate that PP1 regulation of sarcomere function at MLC2a is a main regulator of atrial contractility in AF.

scholarly journals Impact of the Order of Initiation of Fluconazole and Amphotericin B in Sequential or Combination Therapy on Killing of Candida albicans In Vitro and in a Rabbit Model of Endocarditis and Pyelonephritis

2001 ◽  
Vol 45 (2) ◽  
pp. 485-494 ◽  
Author(s):  
Arnold Louie ◽  
Pamela Kaw ◽  
Partha Banerjee ◽  
Weiguo Liu ◽  
George Chen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Induced Resistance ◽  
Rabbit Model ◽  
In Vivo Studies ◽  
Infection Model ◽  
Simultaneous Exposure ◽  
The Impact

ABSTRACT In vitro time-kill studies and a rabbit model of endocarditis and pyelonephritis were used to define the impact that the order of exposure of Candida albicans to fluconazole (FLC) and amphotericin B (AMB), as sequential and combination therapies, had on the susceptibility of C. albicans to AMB and on the outcome. The contribution of FLC-induced resistance to AMB for C. albicans also was assessed. In vitro, AMB monotherapy rapidly killed each of four C. albicans strains; FLC alone was fungistatic. Preincubation of these fungi with FLC for 18 h prior to exposure to AMB decreased their susceptibilities to AMB for 8 to >40 h. Induced resistance to AMB was transient, but the duration of resistance increased with the length of FLC preincubation. Yeast sequentially incubated with FLC followed by AMB plus FLC (FLC→AMB+FLC) showed fungistatic growth kinetics similar to that of fungi that were exposed to FLC alone. This antagonistic effect persisted for at least 24 h. Simultaneous exposure of C. albicans to AMB and FLC [AMB+FLC(simult)] demonstrated activity similar to that with AMB alone for AMB concentrations of ≥1 μg/ml; antagonism was seen using an AMB concentration of 0.5 μg/ml. The in vitro findings accurately predicted outcomes in our rabbit infection model. In vivo, AMB monotherapy and treatment with AMB for 24 h followed by AMB plus FLC (AMB→AMB+FLC) rapidly sterilized kidneys and cardiac vegetations. AMB+FLC(simult) and FLC→AMB treatments were slower in clearing fungi from infected tissues. FLC monotherapy and FLC→AMB+FLC were both fungistatic and were the least active regimens. No adverse interaction was observed between AMB and FLC for the AMB→FLC regimen. However, FLC→AMB treatment was slower than AMB alone in clearing fungi from tissues. Thus, our in vitro and in vivo studies both demonstrate that preexposure of C. albicans to FLC reduces fungal susceptibility to AMB. The length of FLC preexposure and whether AMB is subsequently used alone or in combination with FLC determine the duration of induced resistance to AMB.

scholarly journals Hyperstimulation of CaSR in human MSCs by biomimetic apatite inhibits endochondral ossification via temporal down-regulation of PTH1R

2018 ◽  
Vol 115 (27) ◽  
pp. E6135-E6144 ◽  
Author(s):  
Melika Sarem ◽  
Miriam Heizmann ◽  
Andrea Barbero ◽  
Ivan Martin ◽  
V. Prasad Shastri
Keyword(s):  
Endochondral Ossification ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
In Vivo Studies ◽  
Human Mscs ◽  
Down Regulation ◽  
Calcium Sensing ◽  
Biomimetic Apatite ◽  
The Impact

In adult bone injuries, periosteum-derived mesenchymal stem/stromal cells (MSCs) form bone via endochondral ossification (EO), whereas those from bone marrow (BM)/endosteum form bone primarily through intramembranous ossification (IMO). We hypothesized that this phenomenon is influenced by the proximity of MSCs residing in the BM to the trabecular bone microenvironment. Herein, we investigated the impact of the bone mineral phase on human BM-derived MSCs’ choice of ossification pathway, using a biomimetic bone-like hydroxyapatite (BBHAp) interface. BBHAp induced hyperstimulation of extracellular calcium-sensing receptor (CaSR) and temporal down-regulation of parathyroid hormone 1 receptor (PTH1R), leading to inhibition of chondrogenic differentiation of MSCs even in the presence of chondroinductive factors, such as transforming growth factor-β1 (TGF-β1). Interestingly rescuing PTH1R expression using human PTH fragment (1–34) partially restored chondrogenesis in the BBHAp environment. In vivo studies in an ectopic site revealed that the BBHAp interface inhibits EO and strictly promotes IMO. Furthermore, CaSR knockdown (CaSR KD) disrupted the bone-forming potential of MSCs irrespective of the absence or presence of the BBHAp interface. Our findings confirm the expression of CaSR in human BM-derived MSCs and unravel a prominent role for the interplay between CaSR and PTH1R in regulating MSC fate and the choice of pathway for bone formation.

Abstract 11: Thioredoxin-Interacting Protein Is Required for VEGF-Induced Angiogenesis Through Regulation of VEGFR2 Internalization

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Shin-Young Park ◽  
Chen Yan ◽  
Bradford C Berk
Keyword(s):  
Umbilical Vein ◽  
Fold Increase ◽  
Tube Formation ◽  
In Vivo Studies ◽  
Vegf Receptor ◽  
Cell Fractionation ◽  
Interacting Protein ◽  
Thioredoxin Interacting Protein

Introduction— Thioredoxin-interacting protein (TXNIP) is an arrestin-like scaffold protein. We have shown previously that it is necessary for the transactivation of the vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) as well as promoting the migration and survival of endothelial cells (ECs). However, its roles in VEGF-induced angiogenesis and in vivo studies of TXNIP function have not been elucidated. Hypothesis— TXNIP regulates VEGF-mediated angiogenesis through modulation of angiogenic signaling pathways in ECs. Methods and Results— To determine the functions of TXNIP in ECs, we generated endothelial-specific TXNIP knockout (EC-TXNIP KO) mice (TXNIPflox/flox: Tie2-Cre/+). These mice displayed impaired capillary growth of the retinal vasculature compared to control mice. Furthermore, aortic rings from EC-TXNIP KO mice exhibited fewer and shorter vascular sprouts than those in control mice. To investigate the role of TXNIP in the regulation of VEGF-induced angiogenesis, we determined the subcellular localization of TXNIP in human umbilical vein EC (HUVEC). Immunofluorescence and cell fractionation studies revealed that upon VEGF stimulation (10ng/ml). TXNIP translocated from cytoplasm to the plasma membrane. There was a 9 fold increase of membrane associated TXNIP with a peak at 15 minutes compared to non-VEGF treatment cells. We hypothesized that membrane associated TXNIP may modulate VEGFR2 internalization and thereby affect VEGF-induced signaling and angiogenesis. To investigate this, we performed in vitro cell surface biotinylation assays in HUVEC. VEGFR2 internalization was decreased by 65% in TXNIP siRNA knockdown cells compared to control siRNA treated cells following VEGF stimulation. Consistent with this result, VEGF-induced phosphorylation of VEGFR2, PLCγ and ERK1/2 was decreased by knockdown of TXNIP. Significantly, TXNIP knockdown inhibited VEGF-induced proliferation and tube formation in vitro. Conclusion— Our results suggest that TXNIP can modulate VEGF-induced angiogenesis and signaling by regulation of VEGFR2 internalization.

Abstract 358: Transient Receptor Potential Vanilloid 2 (TRPV2) contributes to myocardial contractility and hypertrophy via sarcoplasmic reticulum calcium handling

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Jack Rubinstein ◽  
Vivek P Singh ◽  
Valerie M Lasko ◽  
Sheryl E Koch ◽  
Evangelia Kranias ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Fold Increase ◽  
Calcium Handling ◽  
Heart Weight ◽  
Transient Receptor Potential Vanilloid ◽  
Cardiomyocyte Contractility ◽  
Transient Receptor

Background: TRPV2 is a Ca2+ channel that we have recently discovered in cardiomyocytes. The absence of this channel negatively impacts baseline contractility while stimulation results in a positive inotropic response. What remains to be established is the mechanism of this receptor and its role, if any, in the development of hypertrophy. Methods and Results: We obtained isolated cardiomyocytes from wild type (WT) and TRPV2-/- (KO) mice and found that the sarcoplasmic reticulum Ca2+ content and Ca2+ transients were reduced along with fractional shortening in the KO cardiomyocytes (figure, panels A, B, C). In vivo echocardiography confirmed a decrease in ejection fraction in KO mice in comparison to the WT counterparts (panel D). The relevance of these findings was examined in 6 WT and 5 KO mice subjected to transverse aortic constriction (TAC). These mice were followed by echocardiography weekly for a total of 8 weeks post TAC. At the conclusion, the hearts were obtained for histological and molecular analyses. We demonstrated that the KO mice developed less LV hypertrophy in comparison to WT (via echocardiography and by heart weight/body weight ratios) (figure, panels E and F). Importantly, there was a 5 fold increase in TRPV2 expression assessed by PCR in TAC WT hearts, compared to WT not subjected to TAC (0.72±0.10 vs. 0.13±0.04; p<0.01). This suggests a role for TRPV2 not only in contractility, but also in the development of hypertrophy. Conclusions: We have discovered a novel cardiac channel that alters Ca2+ cycling and is capable of modulating cardiomyocyte contractility and hypertrophy, which could lead to novel therapeutic options in heart failure and hypertrophy.

scholarly journals Role of Hyaluronan in Human Adipogenesis: Evidence from in-Vitro and in-Vivo Studies

2019 ◽  
Vol 20 (11) ◽  
pp. 2675 ◽  
Author(s):  
Nicholas Wilson ◽  
Robert Steadman ◽  
Ilaria Muller ◽  
Mohd Draman ◽  
D. Aled Rees ◽  
...  
Keyword(s):  
Stem Cell Differentiation ◽  
In Vivo Studies ◽  
Peroxisome Proliferator ◽  
Synthesis Inhibitor ◽  
Peroxisome Proliferator Activated Receptor ◽  
Inhibitory Role ◽  
The Impact

Hyaluronan (HA), an extra-cellular matrix glycosaminoglycan, may play a role in mesenchymal stem cell differentiation to fat but results using murine models and cell lines are conflicting. Our previous data, illustrating decreased HA production during human adipogenesis, suggested an inhibitory role. We have investigated the role of HA in adipogenesis and fat accumulation using human primary subcutaneous preadipocyte/fibroblasts (PFs, n = 12) and subjects of varying body mass index (BMI). The impact of HA on peroxisome proliferator-activated receptor gamma (PPARγ) expression was analysed following siRNA knockdown or HA synthase (HAS)1 and HAS2 overexpression. PFs were cultured in complete or adipogenic medium (ADM) with/without 4-methylumbelliferone (4-MU = HA synthesis inhibitor). Adipogenesis was evaluated using oil red O (ORO), counting adipogenic foci, and measurement of a terminal differentiation marker. Modulating HA production by HAS2 knockdown or overexpression increased (16%, p < 0.04) or decreased (30%, p = 0.01) PPARγ transcripts respectively. The inhibition of HA by 4-MU significantly enhanced ADM-induced adipogenesis with 1.52 ± 0.18- (ORO), 4.09 ± 0.63- (foci) and 2.6 ± 0.21-(marker)-fold increases compared with the controls, also increased PPARγ protein expression (40%, (p < 0.04)). In human subjects, circulating HA correlated negatively with BMI and triglycerides (r = −0.396 (p = 0.002), r = −0.269 (p = 0.038), respectively), confirming an inhibitory role of HA in human adipogenesis. Thus, enhancing HA action may provide a therapeutic target in obesity.

scholarly journals Exposure to airborne gold nanoparticles: a review of current toxicological data on the respiratory tract

2020 ◽  
Vol 22 (8) ◽  
Author(s):  
Barbara De Berardis ◽  
Magda Marchetti ◽  
Anna Risuglia ◽  
Federica Ietto ◽  
Carla Fanizza ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Human Health ◽  
Large Scale ◽  
Current Knowledge ◽  
Engineered Nanoparticles ◽  
In Vivo Studies ◽  
Field Exposure ◽  
The Impact

AbstractIn recent years, the introduction of innovative low-cost and large-scale processes for the synthesis of engineered nanoparticles with at least one dimension less than 100 nm has led to countless useful and extensive applications. In this context, gold nanoparticles stimulated a growing interest, due to their peculiar characteristics such as ease of synthesis, chemical stability and optical properties. This stirred the development of numerous applications especially in the biomedical field. Exposure of manufacturers and consumers to industrial products containing nanoparticles poses a potential risk to human health and the environment. Despite this, the precise mechanisms of nanomaterial toxicity have not yet been fully elucidated. It is well known that the three main routes of exposure to nanomaterials are by inhalation, ingestion and through the skin, with inhalation being the most common route of exposure to NPs in the workplace. To provide a complete picture of the impact of inhaled gold nanoparticles on human health, in this article, we review the current knowledge about the physico-chemical characteristics of this nanomaterial, in the size range of 1–100 nm, and its toxicity for pulmonary structures both in vitro and in vivo. Studies comparing the toxic effect of NPs larger than 100 nm (up to 250 nm) are also discussed.

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