[Effect of acupuncture on pain and cerebral hemodynamics in patients with migraine: a randomized controlled trial].

OBJECTIVE: To observe the therapeutic effect between acupuncture combined with medication and simple medication on migraine and cerebral hemodynamics. METHODS: A total of 120 patients with migraine were randomized into an acupuncture plus medication group (60 cases, 3 cases dropped off) and a medication group (60 cases, 6 cases dropped off). In the medication group, flunarizine hydrochloride capsule was given orally before sleep, 10 mg a day. On the basis of the treatment in the medication group, acupuncture was applied at Sizhukong (TE 23), Shuaigu (GB 8), Taiyang (EX-HN 5), Fengchi (GB 20) and etc. in the acupuncture plus medication group, 30 min each time, once a day. Treatment for 4 weeks was required in both groups. Before and after treatment, the visual analogue scale (VAS) score, indexes of cerebral hemodynamic [blood flow velocity of anterior cerebral artery (ACA), middle cerebral artery (MCA), posterior cerebral artery (PCA), vertebral artery (VA) and basilar artery (BA)] and total TCM syndrome score were observed, and the clinical therapeutic effect and the incidence of the adverse events were evaluated in both groups. RESULTS: Compared before treatment, the VAS scores, the blood flow velocity of ACA, MCA, PCA, VA, BA and the total TCM syndrome scores were decreased in both groups (P<0.05). After treatment, the VAS score, the blood flow velocity of ACA, MCA, PCA, VA, BA and the total TCM syndrome score in the acupuncture plus medication group were lower than those in the medication group (P<0.05). The total effective rate was 96.5% (55/57) in the acupuncture plus medication group, which was superior to 90.7% (49/54) in the medication group (P<0.05). There was no statistical difference in the incidence of adverse events between the two groups (P>0.05). CONCLUSION: Acupuncture combined with flunarizine hydrochloride capsule can effectively relieve the pain in patients with migraine, reduce the cerebral blood flow velocity, the efficacy is superior to simple flunarizine hydrochloride capsule.

Function analysis of differentially expressed microRNAs in TGF-ß1-induced cardiac fibroblasts differentiation.

BACKGROUND: Cardiac fibroblasts differentiation plays a critical role in cardiac remodeling and failure, but the underlying molecular mechanisms are still poorly understood. MicroRNAs (miRNAs) had been identified as important regulators during cell differentiation. The aim of the present study was to screen the miRNAs involved in regulation of cardiac fibroblasts differentiation. METHODS: The differentiation of rat cardiac fibroblasts into myofibroblasts was induced by transforming growth factor-ß1 (TGF-ß1). Small RNA sequencing was then applied to detect the differentially expressed miRNAs. RESULTS: A total of 450 known miRNAs were detected, and 127 putative novel miRNAs were predicted by miRDeep2 analysis. DEGseq analysis and qRT-PCR confirmed that 24 known miRNAs were differentially expressed in TGF-ß1-induced cardiac fibroblasts, including three up-regulated miRNAs and 21 down-regulated miRNAs. After miRNAs target genes prediction by miRanda algorithm, pathway analysis showed that these potential target genes were involved in Calcium signaling pathway, Type II diabetes mellitus, and Glutamatergic synapse pathway, etc. Meanwhile, seven putative miRNAs were also detected differentially expressed during TGF-ß1-induced cardiac fibroblasts differentiation. CONCLUSIONS: These differentially expressed miRNAs might play critical roles in cardiac fibroblasts differentiation. Altered expression of miRNAs may yield new insights into the underlying mechanisms of cardiac fibrosis and provide novel mechanism-based therapeutic strategies for cardiac fibrosis.

Screening and Function Analysis of MicroRNAs Involved in Exercise Preconditioning-Attenuating Pathological Cardiac Hypertrophy.

Exercise preconditioning (EP) attenuates pathological cardiac hypertrophy by increasing the functional capacity of the cardiovascular system; however, the underlying molecular mechanisms remain unclear. MicroRNAs (miRNAs) play important roles in various physiological and pathological processes by regulating the expression of the targeted gene. In this study, we aimed to screen the miRNAs involved in EP-attenuating pathological cardiac hypertrophy. The histological and echocardiographic parameters assessment showed that pathological cardiac hypertrophy induced by transverse aortic constriction (TAC) was significantly alleviated in EP treated rats. The left ventricular tissues (n = 3) from Sham, TAC and EP + TAC groups were subjected to small RNA deep sequencing. A total of 570 known mature miRNAs and 530 putative novel miRNAs were detected. DEGseq analysis showed that there were 37 and 88 differentially expressed miRNAs in the comparisons of TAC versus Sham and EP + TAC versus TAC, respectively. Among them, EP treatment could relieve the expression changes of 32 miRNAs, which were supposed to be involved in EP-attenuating pathological cardiac hypertrophy. After miRNAs target genes prediction by miRDB algorithm, pathway analysis showed that the most frequently represented pathways were involved in Calcium signaling pathway and MAPK signaling pathway. The results would provide valuable clues to finding therapeutic targets for the treatment of pathological cardiac hypertrophy.

Transcriptional up-regulation of relaxin-3 by Nur77 attenuates ß-adrenergic agonist-induced apoptosis in cardiomyocytes.

The relaxin family peptides have been shown to exert several beneficial effects on the heart, including anti-apoptosis, anti-fibrosis, and anti-hypertrophy activity. Understanding their regulation might provide new opportunities for therapeutic interventions, but the molecular mechanism(s) coordinating relaxin expression in the heart remain largely obscured. Previous work demonstrated a role for the orphan nuclear receptor Nur77 in regulating cardiomyocyte apoptosis. We therefore investigated Nur77 in the hopes of identifying novel relaxin regulators. Quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) data indicated that ectopic expression of orphan nuclear receptor Nur77 markedly increased the expression of latexin-3 (RLN3), but not relaxin-1 (RLN1), in neonatal rat ventricular cardiomyocytes (NRVMs). Furthermore, we found that the ß-adrenergic agonist isoproterenol (ISO) markedly stimulated RLN3 expression, and this stimulation was significantly attenuated in Nur77 knockdown cardiomyocytes and Nur77 knockout hearts. We showed that Nur77 significantly increased RLN3 promoter activity via specific binding to the RLN3 promoter, as demonstrated by electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assays. Furthermore, we found that Nur77 overexpression potently inhibited ISO-induced cardiomyocyte apoptosis, whereas this protective effect was significantly attenuated in RLN3 knockdown cardiomyocytes, suggesting that Nur77-induced RLN3 expression is an important mediator for the suppression of cardiomyocyte apoptosis. These findings show that Nur77 regulates RLN3 expression, therefore suppressing apoptosis in the heart, and suggest that activation of Nur77 may represent a useful therapeutic strategy for inhibition of cardiac fibrosis and heart failure.

Transcatheter Closure of Perimembranous Ventricular Septal Defects Using Dual Wire-Maintaining Technique.

OBJECTIVE: The present study was designed to evaluate the safety and feasibility of transcatheter closure of perimembranous ventricular septal defects (PmVSDs) with dual wire-maintaining technique (DWMT). PATIENTS/METHODS: From January 2010 to December 2013, a total of 241 patients (men: 109, women: 132; mean age: 22.2±15.4 years) with congenital PmVSDs were randomised to either the conventional technique (CT) group (n=118) or the DWMT group (n=123). RESULTS: In the CT group, the track wire was withdrawn before occluder insertion. In the DWMT group, the track wire was maintained in the delivery sheath during the procedure. Both the procedure time and fluoroscope time were reduced significantly in the DWMT group patients who required device replacement compared with CT group patients (median time: 46.0±14.8min vs. 56.0±15.2min, p<0.05; 15.0±11.6min vs. 22.0±10.1min, p<0.05). There was no difference in the incidence of complications between the two groups. CONCLUSION: The DWMT is safe and feasible for transcatheter treatment of PmVSDs, especially in patients requiring device replacement, for it avoids reconstruction of the "arteriovenous wire loop", left ventriculography from the contralateral femoral route, or the use of a larger femoral artery short sheath.

Complete atrioventricular block after percutaneous device closure of perimembranous ventricular septal defect: A single-center experience on 1046 cases.

BACKGROUND: Complete atrioventricular block (cAVB) has been deemed a rare complication after transcatheter closure for ventricular septal defect (VSD). However, this serious event appears to be underrecognized and is worth being investigated further. OBJECTIVES: To determine the incidence and predisposing factors of cAVB associated with closure of VSD using a modified double-disk occluder (MDO). METHODS: From December 21, 2001 to December 31, 2014, 1046 patients with perimembranous ventricular septal defect underwent percutaneous closure using the MDO. Electrocardiography was evaluated before the procedure, within 1 week after the procedure, and then at 1, 3, 6, and 12 months and every year thereafter. Other baseline and procedural parameters were also evaluated and a comparison between patients requiring pacemakers and those not suffering from cAVB was done. RESULTS: cAVB occurred in 17 patients (1.63%) after the procedure. Of the 17 patients, 8 underwent permanent pacemaker (PPM) implantation. The cAVB occurred within 30 days after the procedure in 14 patients and after 1 year in 3 patients. In comparison patients aged ≤18 years, patients aged >18 years were more prone to cAVB (P = .025). Logistic regression revealed no significant parameter to predict later requirement for PPM. CONCLUSIONS: The incidence of cAVB after transcatheter closure of VSD was acceptable, as part of the cAVB population recovered after administration of corticosteroid and application of a temporary pacemaker. Late cAVB (>1 year) appears to make it more difficult to restore normal conduction block. Because of the recurrence of cAVB, life-long follow-up with periodic electrocardiography examination may be mandatory.

Orphan nuclear receptor Nur77 is a novel negative regulator of endothelin-1 expression in vascular endothelial cells.

Endothelin-1 (ET-1) produced by vascular endothelial cells plays essential roles in the regulation of vascular tone and development of cardiovascular diseases. The objective of this study is to identify novel regulators implicated in the regulation of ET-1 expression in vascular endothelial cells (ECs). By using quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA), we show that either ectopic expression of orphan nuclear receptor Nur77 or pharmacological activation of Nur77 by 6-mercaptopurine (6-MP) substantially inhibits ET-1 expression in human umbilical vein endothelial cells (HUVECs), under both basal and thrombin-stimulated conditions. Furthermore, thrombin-stimulated ET expression is significantly augmented in both Nur77 knockdown ECs and aort from Nur77 knockout mice, suggesting that Nur77 is a negative regulator of ET-1 expression. Inhibition of ET-1 expression by Nur77 occurs at gene transcriptional levels, since Nur77 potently inhibits ET-1 promoter activity, without affecting ET-1 mRNA stability. As shown in electrophoretic mobility shift assay (EMSA), Nur77 overexpression markedly inhibits both basal and thrombin-stimulated transcriptional activity of AP-1. Mechanistically, we demonstrate that Nur77 specially interacts with c-Jun and inhibits AP-1 dependent c-Jun promoter activity, which leads to a decreased expression of c-Jun, a critical component involved in both AP-1 transcriptional activity and ET-1 expression in ECs. These findings demonstrate that Nur77 is a novel negative regulator of ET-1 expression in vascular ECs through an inhibitory interaction with the c-Jun/AP-1 pathway. Activation of Nur77 may represent a useful therapeutic strategy for preventing certain cardiovascular diseases, such as atherosclerosis and pulmonary artery hypertension.

MicroRNA-663 regulates human vascular smooth muscle cell phenotypic switch and vascular neointimal formation.

RATIONALE: Abnormal phenotypic switch of vascular smooth muscle cell (VSMC) is a hallmark of vascular disorders such as atherosclerosis and restenosis after angioplasty. MicroRNAs (miRNAs) have emerged as important regulators for VSMC function, and we recently identified miR-663 as critical for controlling human aortic smooth muscle cell proliferation. OBJECTIVE: To investigate whether miR-663 plays a role in human VSMC phenotypic switch and the development of neointima formation. METHODS AND RESULTS: By using quantitative reverse-transcription polymerase chain reaction, we found that miR-663 was significantly downregulated in human aortic VSMCs on platelet-derived growth factor treatment, whereas expression was markedly increased during VSMC differentiation. Furthermore, we demonstrated that overexpression of miR-663 increased expression of VSMC differentiation marker genes, such as smooth muscle 22α, smooth muscle α-actin, calponin, and smooth muscle myosin heavy chain, and potently inhibited platelet-derived growth factor-induced VSMC proliferation and migration. We identified the transcription factor JunB and myosin light chain 9 as downstream targets of miR-663 in human VSMCs, because overexpression of miR-663 markedly inhibited expression of JunB and its downstream molecules, such as myosin light chain 9 and matrix metalloproteinase 9. Finally, we showed that adeno-miR-663 markedly suppressed the neointimal lesion formation by ≈50% in mice after vascular injury induced by carotid artery ligation, specifically via decreased JunB expression. CONCLUSIONS: These results indicate that miR-663 is a novel modulator of human VSMC phenotypic switch by targeting JunB/myosin light chain 9 expression. These findings suggest that targeting miR-663 or its specific downstream targets in human VSMCs may represent an attractive approach for the treatment of proliferative vascular diseases.

MicroRNA-638 is highly expressed in human vascular smooth muscle cells and inhibits PDGF-BB-induced cell proliferation and migration through targeting orphan nuclear receptor NOR1.

AIMS: Aberrant vascular smooth muscle cell (VSMC) proliferation and migration contribute significantly to the development of vascular pathologies, such as atherosclerosis and restenosis. MicroRNAs have recently emerged as critical modulators in cellular processes and the purpose of this study is to identify novel miRNA regulators implicated in human aortic VSMC proliferation and migration. METHODS AND RESULTS: To identify miRNAs that are differentially expressed in human VSMCs, we performed miRNA microarray analysis in human aortic smooth muscle cells (SMCs) at different time points after platelet-derived growth factor (PDGF) stimulation. Here, we identified microRNA-638 (miR-638) as a transcript that was one of the most significantly down-regulated in human VSMCs after PDGF stimulation. Furthermore, we confirmed, by Quantitative RT-PCR, that miR-638 is highly expressed in human VSMCs, and its expression is markedly down-regulated in a dose- and time-dependent manner upon PDGF treatment. Consistent with a critical role in SMC proliferation, we found that miR-638 expression was significantly up-regulated in human VSMCs cultured in differentiation medium, a condition that inhibits SMC proliferation. Furthermore, we identified the orphan nuclear receptor NOR1 as a downstream target gene product of miR-638 and down-regulation of NOR1 is critical for miR-638-mediated inhibitory effects on PDGF-induced cyclin D1 expression, cell proliferation, and migration in human aortic SMCs. CONCLUSION: These results indicate that miR-638 is a key molecule in regulating human VSMC proliferation and migration by targeting the NOR1/cyclin D pathway and suggest that specific modulation of miR-638 in human VSMCs may represent an attractive approach for the treatment of proliferative vascular diseases.

Deterioration of cardiac function after acute myocardial infarction is prevented by transplantation of modified endothelial progenitor cells overexpressing endothelial NO synthases.

BACKGROUND/AIMS: Stem cell transplantation and gene therapies have been shown to attenuate myocardial dysfunction after myocardial infarction (AMI) in different acute and chronic animal models. The aim of this study was to assess the potential therapeutic efficacy of endothelial NO synthases (eNOS)-expressing endothelial progenitor cells (EPCs) on infarcted hearts. METHODS: Lentiviral eNOS-infected EPCs were injected after 1 h of ligation of the left anterior descending artery (LAD). The pro-inflammatory cytokines TNF-α and IL-1ß levels in cardiac tissue were measured by ELISA at 3 days after transplantation. 28 days post AMI (before sacrifice), Left ventricular function of each group was determined by echocardiography and pressure-volume system. Cardiac tissues were analyzed with hematoxylin and eosin (H&E) staining and immunohistochemisty. eNOS expression in cardiac tissues was detected by western blot, and NO production of cardiac tissues was determined using an NO assay kit. RESULTS: TNF-α and IL-1ß levels in cardiac tissue were decreased significantly at 3 days after transplantation of lentiviral with eNOS infected EPCs compared to medium control, eNOS lentiviral vector and normal EPCs. At the 28 day after AMI, echocardiography and hemodynamic measurements, and isolated heart studies showed great therapeutic efficacy in improvement of cardiac function, reduction of infarcted size and improvement of vascular densities in the peri-infarct region after intramyocardial application of lentiviral eNOS-infected EPCs compared to medium control, eNOS lentiviral vector and normal EPCs. The eNOS over-expression in cardiac tissue was observed in the eNOS-EPCs and eNOS lentiviral vector group, and NO levels were increased significantly in the eNOS-EPCs and eNOS lentiviral vector group compared to the other three groups (sham operated group, transplantation of medium or EPCs group). CONCLUSION: EPCs can be an attractive vehicle for the exogenous eNOS expression into heart after infarction, which is beneficial to prevent deterioration and promote restoration of cardiac function after AMI by improving angiogenesis.

Potential candidate genes for alveolar hypoxia identified by transcriptome network analysis.

BACKGROUND. Alveolar hypoxia is an important condition related to many disorders such as chronic pulmonary hypertension, pulmonary vasoconstriction, and pulmonary vascular remodeling. The aim of present study was to disclose the biological response and the potential transcriptome networks regulating the hypoxia response in the lungs. MATERIALS AND METHODS. In this study, the microarray dataset GSE11341 was used to construct a regulatory network and identify the potential genes related to alveolar hypoxia. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) term enrichment analyses were also performed. RESULTS. Hypoxia inducible factor 1 alpha (HIF-1α), peroxisome proliferator-activated receptor gamma (PPARγ), and nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-кB) were to be the hub nodes in the transcriptome network. HIF-1α may regulate potassium voltage-gated channel, shaker-related subfamily, member (5KCNA5), solute carrier family 2 (facilitated glucose transporter), member (1SLC2A1), and heme oxygenase (decycling) 1 (HMOX1) expression through the regulation of membrane potential, glucose metabolism, and anti-inflammation pathways. HMOX-1 mediates signaling pathways that relate to NF-кB. CCND1 (cyclin D1) expression could be regulated by PPARγ and HIF-1α via the cell cycle pathway. In addition, new transcriptional factors and target genes, such as phosphofructokinase (PFKL, liver), aldolase A (ALDOA, fructose-bisphosphate), and trefoil factor 3 (intestinal) (TFF3), were also identified. CONCLUSIONS. Transcriptome network analysis is a helpful method for the identification of the candidate genes in alveolar hypoxia. The KEGG pathway and GO term analysis are beneficial in the prediction of the underlying molecular mechanism of these identified genes in alveolar hypoxia.

Vascular smooth muscle cell proliferation is influenced by let-7d microRNA and its interaction with KRAS.

BACKGROUND: Several microRNAs (miRNAs) have been reported to regulate cardiovascular biological and pathological processes through inhibiting the translation of certain RNA transcripts. However, little is known about the association between miRNAs and vascular smooth muscle cell (VSMC) proliferation. The aim was to investigate the role of miRNAs in VSMC growth and the potential mechanism. METHODS AND RESULTS: Primary VSMCs were isolated from the medial layer of the thoracic aorta obtained from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). miRNA microarrays were used to analyze the difference in miRNA expression between VSMCs of SHR and WKY rats and were validated using TaqMan real-time PCR. Of the potentially related genes under the influence of let-7d identified through literature search, KRAS was verified by western blot and functionally analyzed using miRNA mimics transfection and analysis of transfectants by cell enumeration was made using CCK-8 and flow cytometric analysis of cell cycle progression. let-7d-transfected VSMCs from SHR, WKY and human coronary arteries expressed significantly lower amounts of KRAS protein, displayed reduced cell growth and led to a greater number of cells in the G1 phase than the G2/M phases of the cell cycle. CONCLUSIONS: let-7d was significantly downregulated in VSMCs as an important regulator of cell proliferation. RAS might be involved in the proliferation regulation by let-7d.

Transcatheter device closure of intracristal ventricular septal defects.

Transcatheter closure of ventricular septal defects (VSDs) is now offered as primary therapy at many institutions. We sought to evaluate the clinical feasibility and safety of device closure of intracristal VSDs using perimembranous occluders. A total of 49 patients were diagnosed with intracristal VSDs and assigned to the intracristal VSD group, and another 49 patients with the same size perimembranous VSDs were selected and assigned to the perimembranous VSD group. Two types of perimembranous occluders, symmetric and asymmetric, were used, and no difference was found between the groups with respect to successful closure. The diameter of the intracristal VSD was 3 to 10 mm (mean 5.8 ± 1.4) on the transthoracic echocardiogram. The procedure time and fluoroscope time in the intracristal VSD group were significantly greater than those in the perimembranous VSD group. More defects with a subaortic rim ≤ 2 mm on the transthoracic echocardiogram were present in the intracristal VSD group than in the perimembranous VSD group; thus, more asymmetric occluders were used in the intracristal VSD group. All devices remained in a stable position and in an optimal shape during follow-up. In conclusion, transcatheter closure of intracristal VSDs with the perimembranous occluder is feasible, safe, and effective.

[Outcome of transcatheter closure of perimembranous ventricular septal defect with modified double-disk occluder device].

OBJECTIVE: To evaluate the efficacy and adverse effects of transcatheter closure of perimembranous ventricular septal defect (pmVSD) with modified double-disk occluder device (MDVO). METHODS: Clinical data including clinical examination, electrocardiography daily after the procedure for a week, chest-X-rays and TTE before discharge and at 3-5 days after the procedure were analyzed from 604 patients underwent percutaneous closure of a pmVSD with MDVO at our department between December 2001 and December 2008. RESULTS: Procedure was successful in 576 out of 604 patients (95.4%) and 583 VSD occluders were placed. Endocarditis, thromboembolism, or deaths were not observed after procedure. Conduction block occurred in 81 patients (56 RBBB, 14 LBBB) and transient nonparoxysmal ventricular tachycardia in 31 patients after the procedure. Complete heart block occurred in 11 patients, 9 of them recovered in 3 weeks, permanent pacemaker was implanted in 2 patients (one had transient III degrees AVB before the procedure, the other underwent simultaneous closure of ventricular septal defect and atrial septal defect). Trivial/small residual shunts were found in 69 patients (12.0%). The residual shunts disappeared in 31 patients and remained unchanged in 38 patients (6.6%) 7 days after procedures. Aortic regurgitation developed in 5 patients (2 trivial/small, 3 small/moderate), and tricuspid regurgitation was present in 35 patients (32 trivial/small, 3 moderate). Five patients developed haemolysis (device retrieved via catheter in 1 patient due to persistent haemolysis, the other 4 patients recovered 3-14 days post procedure). Pseudoaneurysm of femoral artery occurred in 1 patient, and disappeared by pressure dressing. Device was successfully replaced in 2 patients with either device embolization (n = 1) or device misplacement (n = 1) after device retrieval by catheter. CONCLUSION: It is safe and effective to close congenital perimembranous ventricular septal defect with domestic-made occluder device.

Transcatheter closure of perimembranous ventricular septal defects using a novel wire-maintaining technique.

OBJECTIVES: We aimed to evaluate the clinical feasibility and safety of a novel wire-maintaining technique (WMT) for transcatheter closure of perimembranous ventricular septal defects (PmVSDs). BACKGROUND: Transcatheter device closure of PmVSDs has been increasingly performed and this procedure is now offered as primary therapy at many institutions. METHODS: A total of 103 patients with complex PmVSDs were randomized to either the conventional technique (CT) group (n = 51) or the WMT group (n = 52). In the CT group, the track wire was withdrawn before the occluder insertion and deployment. If inappropriate, the initial occluder was withdrawn and the "arteriovenous wire loop" was re-established. In the WMT group, the track wire was maintained in the delivery sheath during the procedure. If the initial occluder was inappropriate, the delivery sheath could be reintroduced over the maintained wire. RESULTS: For those patients who could not achieve optimal results with the initially selected occluders and required further device replacement, the procedure and fluoroscope time was reduced significantly in the WMT group compared with the CT group ([50.8 +/- 13.2] min vs. [61.5 +/- 15.4] min, P < 0.01 and [21.6 +/- 8.6] min vs. [27.3 +/- 7.4] min, P < 0.05; respectively). There was no difference in the incidence of complications of two groups. CONCLUSIONS: The WMT was feasible and safe for the transcatheter treatment of PmVSDs, especially for those complex defects with great challenge. Using this novel technique, the reconstruction of "arteriovenous wire loop" could be avoided in patients requiring device replacement.