RESUMO
The Arabidopsis (Arabidopsis thaliana) blue light photoreceptor phototropin1 (phot1) is a blue light-activated Ser/Thr protein kinase that mediates various light responses, including phototropism. The function of phot1 in hypocotyl phototropism is dependent on the light induction of ROOT PHOTOTROPISM2 (RPT2) proteins within a broad range of blue light intensities. It is not yet known however how RPT2 contributes to the photosensory adaptation of phot1 to high intensity blue light and the phototropic responses under bright light conditions. We show that RPT2 suppresses the activity of phot1 and demonstrate that RPT2 binds to the PHOT1 light, oxygen or voltage sensing1 (LOV1) domain that is required for its high photosensitivity. Our biochemical analyses revealed that RPT2 inhibits autophosphorylation of phot1, suggesting that it suppresses the photosensitivity and/or kinase activity of phot1 through the inhibition of LOV1 function. We found that RPT2 proteins are degraded via a ubiquitin-proteasome pathway when phot1 is inactive and are stabilized under blue light in a phot1-dependent manner. We propose that RPT2 is a molecular rheostat that maintains a moderate activation level of phot1 under any light intensity conditions.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas Serina-Treonina Quinases/genéticaRESUMO
This single-centre prospective feasibility study (UMIN000030232) evaluated whether zinc supplementation was safe and effective for improving outcomes among patients with acute myocardial infarction (AMI). Within 24 h after successful primary percutaneous coronary intervention, consenting patients with AMI were randomly assigned 1:1 to receive conventional treatment (conventional treatment group) or conventional treatment plus zinc acetate supplementation (zinc supplementation group). The two groups were compared in terms of major adverse cardiovascular events (MACE), and scar size, which was evaluated using cardiac magnetic resonance imaging (CMR) at 4 weeks after discharge. A total of 56 patients underwent randomization (with 26 assigned to the zinc supplementation group and 27 to the conventional treatment group). The two groups had generally similar laboratory findings and clinical characteristics. The two groups also had similar lengths of hospital stay and rates of MACE. Forty of the 53 patients underwent CMR and it revealed that % core zone was numerically lower in the zinc supplementation group than in the conventional treatment group (9.3 ± 6.9% vs. 14.2 ± 9.1%, P = 0.07). This small single-centre study failed to detect a significant reduction in mid-term MACE after AMI among patients who received zinc supplementation.
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Infarto do Miocárdio , Intervenção Coronária Percutânea , Humanos , Estudos Prospectivos , Zinco , Infarto do Miocárdio/etiologia , Imageamento por Ressonância Magnética/métodos , Suplementos Nutricionais , Intervenção Coronária Percutânea/efeitos adversos , Resultado do TratamentoRESUMO
This study aimed to determine the optimal cut-off value of the early drop in systolic blood pressure (SBP) for worsening renal function (WRF) in hospitalized patients with heart failure (HF) and analyze predictors of WRF and the early drop in SBP at that threshold. We retrospectively enrolled 396 patients with acute decompensated HF. The early drop in SBP was defined as the difference between baseline and SBP measured 24 h after hospitalization. We performed receiver operating characteristic (ROC) analysis to determine the optimal cut-off value of the early drop in SBP for WRF and evaluated the effect of the early drop in SBP on in-hospital mortality by multivariate logistic regression analyses. The mean age of the patients was 73.4 ± 14.7 years, and 61.2% were men. A 14.0% drop in SBP was identified as the optimal cut-off value for WRF from the ROC curve analysis. An early drop in SBP ≥ 14.0% was associated with WRF in multivariate logistic regression analysis (odds ratio 7.84; 95% confidence interval 4.06-15.14; P < 0.0001). The dose of intravenous furosemide within 24 h of admission was one of the predictors of the early drop in SBP ≥ 14.0%, while no early drop in SBP was a predictor of in-hospital mortality in multivariate logistic regression models. In conclusion, the optimal cut-off value for WRF in patients with HF was a 14.0% drop in SBP within 24 h of admission. The early drop in SBP ≥ 14.0% was one of the predictors of WRF in patients with HF. However, no early drop in SBP was associated with in-hospital mortality. This study was registered with the University Hospital Medical Information Network in Japan (UMIN000035989).
Assuntos
Insuficiência Cardíaca , Masculino , Humanos , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Feminino , Estudos Retrospectivos , Mortalidade Hospitalar , Pressão Sanguínea , Rim/fisiologia , PrognósticoRESUMO
Photosensory adaptation, which can be classified as sensor or effector adaptation, optimizes the light sensing of living organisms by tuning their sensitivity to changing light conditions. During the phototropic response in Arabidopsis (Arabidopsis thaliana), the light-dependent expression controls of blue-light (BL) photoreceptor phototropin 1 (phot1) and its modulator ROOT PHOTOTROPISM2 (RPT2) are known as the molecular mechanisms underlying sensor adaptation. However, little is known about effector adaption in plant phototropism. Here, we show that control of the phosphorylation status of NONPHOTOTROPIC HYPOCOTYL3 (NPH3) leads to effector adaptation in hypocotyl phototropism. We generated unphosphorable and phosphomimetic NPH3 proteins on seven phosphorylation sites in the etiolated seedlings of Arabidopsis. Unphosphorable NPH3 showed a shortening of its retention time in the cytosol and caused an inability to adapt to very low fluence rates of BL (â¼10-5 µmol m-2 s-1) during the phototropic response. In contrast, the phosphomimetic NPH3 proteins had a lengthened retention time in the cytosol and could not enable the adaptation to BL at fluence rates of 10-3 µmol m-2 s-1 or more. Our results indicate that the activation level of phot1 and the corresponding phosphorylation level of NPH3 determine the dissociation rate and the reassociation rate of NPH3 on the plasma membrane, respectively. These mechanisms may moderately maintain the active state of phot1 signaling across a broad range of BL intensities and contribute to the photosensory adaptation of phot1 signaling during the phototropic response in hypocotyls.
Assuntos
Arabidopsis , Fototropismo , Arabidopsis/genética , Arabidopsis/fisiologia , Fosforilação , Fototropismo/fisiologia , Transdução de SinaisRESUMO
BACKGROUND: Central nervous system diseases are common triggers of Takotsubo syndrome. We herein report a rare case of Takotsubo syndrome associated with autoimmune limbic encephalitis. CASE PRESENTATION: A 68-year-old Japanese woman presented to our emergency room with disturbed consciousness. At admission, she showed hypoxemia. Left ventriculography showed akinesia in the middle part of the left ventricle and hyperkinesia in the apical and basal parts of the left ventricle, and the diagnosis of midventricular Takotsubo syndrome was established. However, after an improvement in disturbed consciousness and Takotsubo syndrome symptoms, her brother noticed something wrong with her behavior during his visit to the hospital. Subsequently, we consulted the neurology department 1 week after admission. Her brother revealed a history of abnormal behavior by the patient (such as mistaken entry in the wrong apartment in her building or in another person's car) a few days prior to the onset of disturbed consciousness, suggesting disorientation of place. Brain magnetic resonance imaging showed an increased signal in the medial aspect of the temporal lobes, which was most clearly observed on the fluid-attenuated inversion recovery sequence; additionally, a cerebrospinal fluid analysis revealed mild lymphocytic pleocytosis. Finally, we established a diagnosis of midventricular Takotsubo syndrome associated with autoimmune limbic encephalitis. CONCLUSIONS: It is presumed that the dysfunction of limbic system due to autonomic limbic encephalopathy is associated with exaggerated sympathetic stimulation. This likely resulted in Takotsubo syndrome in our patient.
Assuntos
Doenças Autoimunes/complicações , Encefalite Límbica/complicações , Cardiomiopatia de Takotsubo/etiologia , Função Ventricular Esquerda , Idoso , Doenças Autoimunes/diagnóstico , Doenças Autoimunes/fisiopatologia , Doenças Autoimunes/terapia , Imagem de Difusão por Ressonância Magnética , Eletrocardiografia , Eletroencefalografia , Feminino , Humanos , Encefalite Límbica/diagnóstico , Encefalite Límbica/fisiopatologia , Encefalite Límbica/terapia , Imagem de Perfusão , Valor Preditivo dos Testes , Ventriculografia com Radionuclídeos , Cardiomiopatia de Takotsubo/diagnóstico , Cardiomiopatia de Takotsubo/fisiopatologia , Cardiomiopatia de Takotsubo/terapia , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Anion-conductive ionomers are used for electrolyte membranes in membrane-electrode assemblies and for binders in catalyst layers in anion exchange membrane fuel cells (AEMFCs). The conformations of these ionomers as well as their water distribution are important for designing new efficient/durable anion-conductive ionomers for AEMFCs. For a deeper understanding of the distribution of deuterium oxide (D2O) as a function of depth, neutron reflectometry (NR) was carried out on thin films of an anion exchange ionomer, BAF-QAF, with a thickness of approximately 60 nm formed on a thermally formed SiO2 film on Si(100) and on a 20 nm Pt layer deposited on the SiO2 film at a temperature of 60 °C and relative humidities of 0, 50, 70, and 90%. Clear NR modulation was obtained under each condition. The NR data were fit very well with a three-sublayered model parallel to the substrate with different densities of BAF-QAF and D2O. The influence of the SiO2 and Pt substrates was observed not only at the BAF-QAF/substrate interface but also on the entire thin film. The D2O absorption/desorption behavior in each sublayer differed in the BAF-QAF films cast on SiO2 and Pt. The BAF-QAF/SiO2 interface was rather hydrophilic, while the BAF-QAF/Pt interface was very hydrophobic.
RESUMO
Phototropin1 (phot1) perceives low- to high-fluence blue light stimuli and mediates both the first and second positive phototropisms. High-fluence blue light is known to induce autophosphorylation of phot1, leading to the second positive phototropism. However, the phosphorylation status of phot1 by low-fluence blue light that induces the first positive phototropism had not been observed. Here, we conducted a phosphoproteomic analysis of maize coleoptiles to investigate the fluence-dependent phosphorylation status of Zmphot1. High-fluence blue light induced phosphorylation of Zmphot1 at several sites. Notably, low-fluence blue light significantly increased the phosphorylation level of Ser291 in Zmphot1. Furthermore, Ser291-phosphorylated and Ser369Ser376-diphosphorylated peptides were found to be more abundant in the low-fluence blue light-irradiated sides than in the shaded sides of coleoptiles. The roles of these phosphorylation events in phototropism were explored by heterologous expression of ZmPHOT1 in the Arabidopsis thaliana phot1phot2 mutant. The first positive phototropism was restored in wild-type ZmPHOT1-expressing plants; however, plants expressing S291A-ZmPHOT1 or S369AS376A-ZmPHOT1 showed significantly reduced complementation rates. All transgenic plants tested in this study exhibited a normal second positive phototropism. These findings provide the first indication that low-fluence blue light induces phosphorylation of Zmphot1 and that this induced phosphorylation is crucial for the first positive phototropism.
Assuntos
Proteínas de Arabidopsis/metabolismo , Luz , Fototropismo/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Fosforilação/genética , Fosforilação/efeitos da radiação , Fototropismo/genética , Fototropismo/efeitos da radiação , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/efeitos da radiação , Zea mays/genética , Zea mays/metabolismo , Zea mays/efeitos da radiaçãoRESUMO
Regulation of protein function by phosphorylation and dephosphorylation is an important mechanism in many cellular events. The phototropin blue-light photoreceptors, plant-specific AGCVIII kinases, are essential for phototropic responses. Members of the D6 PROTEIN KINASE (D6PK) family, representing a subfamily of the AGCVIII kinases, also contribute to phototropic responses, suggesting that possibly further AGCVIII kinases may potentially control phototropism. The present study investigates the functional roles of Arabidopsis (Arabidopsis thaliana) AGCVIII kinases in hypocotyl phototropism. We demonstrate that D6PK family kinases are not only required for the second but also for the first positive phototropism. In addition, we find that a previously uncharacterized AGCVIII protein, AGC1-12, is involved in the first positive phototropism and gravitropism. AGC1-12 phosphorylates serine residues in the cytoplasmic loop of PIN-FORMED 1 (PIN1) and shares phosphosite preferences with D6PK. Our work strongly suggests that the D6PK family and AGC1-12 are critical components for both hypocotyl phototropism and gravitropism, and that these kinases control tropic responses mainly through regulation of PIN-mediated auxin transport by protein phosphorylation.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/fisiologia , Hipocótilo/enzimologia , Hipocótilo/fisiologia , Fototropismo/fisiologia , Proteínas Quinases/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes Reporter , Hipocótilo/efeitos da radiação , Ácidos Indolacéticos/metabolismo , Luz , Família Multigênica , Mutação/genética , Fosforilação/efeitos da radiação , Fototropismo/efeitos da radiaçãoRESUMO
An asymmetric auxin distribution pattern is assumed to underlie the tropic responses of seed plants. It is unclear, however, whether this pattern is required for root negative phototropism. We here demonstrate that asymmetric auxin distribution is not required to establish root phototropism in Arabidopsis. Our detailed analyses of auxin reporter genes indicate that auxin accumulates on the irradiated side of roots in response to an incidental gravitropic stimulus caused by phototropic bending. Further, an agravitropic mutant showed a suppression of this accumulation with an enhancement of the phototropic response. In this context, our pharmacological and genetic analyses revealed that both polar auxin transport and auxin biosynthesis are critical for the establishment of root gravitropism, but not for root phototropism, and that defects in these processes actually enhance phototropic responses in roots. The auxin response factor double mutant arf7 arf19 and the auxin receptor mutant tir1 showed a slight reduction in phototropic curvatures in roots, suggesting that the transcriptional regulation by some specific ARF proteins and their regulators is at least partly involved in root phototropism. However, the auxin antagonist PEO-IAA [α-(phenylethyl-2-one)-indole-3-acetic acid] suppressed root gravitropism and enhanced root phototropism, suggesting that the TIR1/AFB auxin receptors and ARF transcriptional factors play minor roles in root phototropism. Taken together, we conclude from our current data that the phototropic response in Arabidopsis roots is induced by an unknown mechanism that does not require asymmetric auxin distribution and that the Cholodny-Went hypothesis probably does not apply to root phototropism.
Assuntos
Arabidopsis/fisiologia , Ácidos Indolacéticos/metabolismo , Fototropismo , Raízes de Plantas/fisiologia , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Vias Biossintéticas , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mutação/genética , Plantas Geneticamente Modificadas , Fatores de Transcrição/metabolismoRESUMO
Anion conductivity at the surfaces of two anion-exchange membranes (AEMs), quaternized ammonium poly(arylene ether) multiblock copolymer (QPE-bl-3) and quaternized ammonium poly(arylene perfluoro-alkylene) copolymer (QPAF-1), synthesized by our group was investigated using current-sensing atomic force microscopy under purified air at various relative humidities. The anion-conducting spots were distributed inhomogeneously on the surface of QPE-bl-3, and the total areas of the anion-conducting spots and the current at each spot increased with humidity. The anion-conductive areas on QPAF-1 were found on the entire surface even at a low humidity. Distribution of the anion-conducting spots on the membrane was found to directly affect the performance of an AEM fuel cell.
RESUMO
Diabetes mellitus is a global disease, and the number of patients with it is increasing. Of various agents for treatment, those that directly act on muscle are currently attracting attention because muscle is one of the main tissues in the human body, and its metabolism is decreased in type II diabetes. In this study, we found that hydroxylamine (HA) enhances glucose uptake in C2C12 myotubes. Analysis of HA's mechanism revealed the involvement of IRS1, PI3K and Akt that is related to the insulin signaling pathway. Further investigation about the activation mechanism of insulin receptor or IRS1 by HA may provide a way to develop a novel anti-diabetic agent alternating to insulin.
Assuntos
Glucose/farmacocinética , Hidroxilamina/farmacologia , Proteínas Substratos do Receptor de Insulina/metabolismo , Fibras Musculares Esqueléticas/efeitos dos fármacos , Animais , Western Blotting , Linhagem Celular , Humanos , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Camundongos , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: Percutaneous coronary intervention (PCI) for lesions with eruptive calcified nodules (CNs) is associated with worse outcomes compared with that for other calcified lesions. We aimed to clarify the relationship between eruptive CNs at index PCI, optical coherence tomography (OCT) findings at the 8-month follow-up, and clinical outcomes using serial OCT. METHODS: This retrospective observational study used data from a prospective, single-centre registry. We conducted consecutive PCI for calcified lesions requiring rotational atherectomy (RA) with OCT guidance. We categorized 51 patients (54 lesions) into those with (16 patients [16 lesions]) and without eruptive CNs (35 patients [38 lesions]). RESULTS: Post-PCI, stent expansion was comparable between the 2 groups, and CN-like protrusion was found in 75% of lesions with eruptive CNs. Follow-up OCT at 8 months revealed in-stent CNs in 54% of treated eruptive CN lesions, whereas lesions without eruptive CNs lacked in-stent CNs. Multivariate linear regression analysis demonstrated that eruptive CN was associated with maximum neointimal tissue (NIT) thickness (regression coefficient 0.303; 95% confidence interval, 0.057-0.549; P = 0.02). Consequently, patients with eruptive CNs exhibited a higher clinically driven target lesion revascularization (TLR) rate than did those without at 1 year (31.3% vs 2.9%, P = 0.009) and 5 years (43.8% vs 11.4%, P = 0.02). TLR primarily occurred in lesions with maximum eruptive CN arc angles > 180°. CONCLUSIONS: Following RA treatment with acceptable stent expansion, eruptive CNs before PCI correlated with greater NIT formation with in-stent CNs, resulting in a higher TLR rate, particularly in lesions with maximum eruptive CN arc angles exceeding 180°.
RESUMO
Hydroxyl radical (OH) is an important oxidant in atmospheric aqueous phases such as cloud and fog drops and water-containing aerosol particles. We find that numerical models nearly always overestimate aqueous hydroxyl radical concentrations because they overpredict its rate of formation and, more significantly, underpredict its sinks. To address this latter point, we examined OH sinks in atmospheric drops and aqueous particles using both new samples and an analysis of published data. Although the molecular composition of organic carbon, the dominant sink of OH, is extremely complex and poorly constrained, this sink behaves very similarly in different atmospheric waters and even in surface waters. Thus, the sink for aqueous OH can be estimated as the concentration of dissolved organic carbon multiplied by a general scavenging rate constant [kC,OH = (3.8 ± 1.9) × 10(8) L (mol C)(-1) s(-1)], a simple process that should significantly improve estimates of OH concentrations in atmospheric drops and aqueous particles.
Assuntos
Atmosfera , Carbono/química , Sequestradores de Radicais Livres/química , Radical Hidroxila/química , Água/química , CinéticaRESUMO
The impact of continuous flow left ventricular assist device (LVAD) pumping on platelet aggregation was investigated in animal experiments utilizing six calves. A single-use MagLev centrifugal blood pump, MedTech MagLev, was used to bypass the calves' hearts from the left atrium to the descending aorta at a flow rate of 50 ml/kg/min. The LVAD's impact on blood coagulation activities was evaluated based on the platelet aggregability, which was measured with a turbidimetric assay method during the preoperative, operative, and postoperative periods. Heparin and warfarin were used for anticoagulation, while aspirin was used for the antiplatelet therapy. A decrease in platelet aggregation immediately after the pump started was observed in the cases of successful long-term pump operation, while the absence of such a decrease might have caused coagulation-related complications to terminate the experiments. Thus, the platelet aggregability was found to be significantly affected by the pump, and its initial trend may be related to the long-term outcome of the mechanical circulatory support.
Assuntos
Derivação Cardíaca Esquerda , Coração Auxiliar , Agregação Plaquetária/fisiologia , Animais , Anticoagulantes/farmacologia , Aspirina/farmacologia , Bovinos , Heparina/farmacologia , Masculino , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Varfarina/farmacologiaRESUMO
A venous aneurysm is characterized by a localized dilated lesion in most major veins. Popliteal venous aneurysms (PVAs) are rare; however, they are one of the causes of deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE), which can be critical due to the high mortality risk. We present a 21-year-old woman without prior medical history, who arrived by ambulance after having a transient cardio-pulmonary arrest. Contrast computed tomography revealed a massive PTE and a right PVA with a thrombus. Laboratory data suggested that she had no thrombotic predisposition. Therefore, we diagnosed her condition as a massive PTE that derived from a thrombus, which arose from the right PVA. After successful intravenous thrombolysis of the PTE and DVT, surgical plication of the right PVA was performed to prevent the recurrence of PTE. She has had no recurrence of PTE or DVT two years after surgical treatment. This case suggests that surgical plication might be an effective way of preventing recurrence in patients with PVA. Learning objective: Popliteal venous aneurysm (PVA) occurrence is rare, but it can result in deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE). To treat our patient who suffered transient cardiac-pulmonary arrest caused by a massive PTE, we first used a recombinant tissue plasminogen activator and anticoagulant therapy. After the condition was stabilized, surgical plication of the right PVA was performed to prevent DVT recurrence. The present case suggests that surgical plication might be beneficial.
RESUMO
We analytically study boundary conditions of the Dirac fermion models on a lattice, which describe the first and second order topological insulators. We obtain the dispersion relations of the edge and hinge states by solving these boundary conditions, and clarify that the Hamiltonian symmetry may provide a constraint on the boundary condition. We also demonstrate the edge-hinge analog of the bulk-edge correspondence, in which the nontrivial topology of the gapped edge state ensures gaplessness of the hinge state.
RESUMO
The blue light photoreceptors, phototropin 1 (phot1) and phot2, and their signal transducer, NONPHOTOTROPIC HYPOCOTYL3 (NPH3), are activators of the phototropic responses of Arabidopsis hypocotyls. In a recent study, we reported that the control of NPH3 phosphorylation at serine 7 (S7: or S5), S213, S223, S237, S467, S474 (or S476), and S722 (or S723) contributes to the photosensory adaptation of phot1 signaling during the phototropic response. Phosphomimetic NPH3SE mutant and unphosphorylatable NPH3SA mutant on those serine residues function efficiently under blue light conditions at fluence rates of 10-5 µmol m-2 s-1 and 10-3 µmol m-2 s-1 or more, respectively. We here demonstrate that phosphomimetic NPH3SE, but not unphosphorylatable NPH3SA, promotes phot2-dependent phototropism under blue light condition at 100 µmol m-2 s-1. This result suggests that phot1 negatively controls phot2 signaling through the dephosphorylation of NPH3 at those residues and that the hyperactivation of phot1- and phot2-NPH3 complexes does not occur at the same time under high intensity blue light. We hypothesize that the dephosphorylation of NPH3 on those serine residues suppresses both phot1 and phot2 signaling, which results in different impacts on phot1- and phot2-dependent hypocotyl phototropism due to the differences in the photosensitivity and activation levels of phot1 and phot2.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Hipocótilo/metabolismo , Luz , Fosfoproteínas/metabolismo , Fosforilação , Fototropinas/metabolismo , Fototropismo/genética , SerinaRESUMO
The TinyPump is an extracorporeal, magnetically driven centrifugal blood pump with its impeller suspended magnetically and hydrodynamically to provide short-term mechanical circulatory support for children and infants. We have previously demonstrated that the in vivo experiments of the experimental TinyPump showed acceptable stable performance at pump flows averaging around 1.0 L/min with low hemolytic and thrombogenic properties for up to 2 weeks. We present here the 1-month in vivo evaluation of the TinyPump, whose design was modified further for more durable operation. The pump was implanted as a left ventricular assist device in five goats (12.5-26.7 kg), with inflow inserted into the left ventricular apex and outflow anastomosed to the descending aorta. Five animals were supported for 110 pump days, with mean pump flow of 1.19 ± 0.03 L/min at a pump speed of 2679 ± 97 rpm. Two animals reached the scheduled end point of 30 days without device failure, and mean plasma-free hemoglobin was 1.7 ± 0.8 mg/dL. Hematologic and biochemical data of these two animals showed no evidence of cardiovascular, renal, or hepatic dysfunction. Although further experiments are needed, the modified TinyPump offers promise as a short-term mechanical circulatory support device in pediatric population.
Assuntos
Coração Auxiliar , Teste de Materiais , Animais , Criança , Circulação Extracorpórea/instrumentação , Cabras , Coração Auxiliar/efeitos adversos , Testes Hematológicos , Hemodinâmica , Humanos , Lactente , Desenho de PróteseRESUMO
Pediatric patients with end-stage heart failure require mechanical circulatory support (MCS) just as adults do. In order to meet the special requirements for neonates' and infants' MCS, pediatric circulatory support devices must be compact with low priming volume, easily controllable with low flow, less traumatic for blood cells and tissues, and biocompatible with minimum anticoagulation. We have designed and developed a miniature rotary centrifugal blood pump, "TinyPump," with a priming volume of 5 mL, which has already demonstrated its controllable performance for low flow and durability in vitro. To evaluate the feasibility of the TinyPump as a left ventricular assist device (LVAD) suitable for neonates and infants, we have examined the biocompatibility and hemodynamic performance of the TinyPump in a pediatric animal model using Shiba goats. The TinyPump is a miniaturized centrifugal pump weighing 150 g comprising a disposable pump head with a 30-mm diameter impeller having six straight-vanes and a reusable motor driver. The impeller in the pump head is supported by a hydrodynamic bearing at its center and is driven by radial magnetic force coupled to the motor driver. TinyPump implantations were performed in 22 Shiba goats (17 female and 5 male), with body weights ranging from 8.4 to 27.2 kg. Under gas anesthesia, via left lateral thoracotomy, a 22 Fr inflow cannula was inserted through the left ventricular apex, while a 6-mm outflow graft was anastomosed to the descending aorta, which were then connected to a TinyPump mounted on the animal's back. Postoperative hemodynamic monitoring included heart rate, arterial and central venous pressure, pump flow, and rotation speed. Target pump flow in all animals was maintained at 0.9 ± 0.1 L/min, which is approximately half the normal pulmonary artery flow measured in control animals. Blood samples were collected to evaluate peripheral organ functions, hemolysis, and thrombosis. Goats were divided into three groups-acute phase (6 h; n = 4), subchronic phase (6 h 2 postoperative days [POD]; n = 11), and chronic phase (3 POD-16 POD; n = 8)-based on their survival duration. In the early experiments, hemolysis and thrombi formation at the impeller bearing resulted in termination of the study. Subsequent modifications of the bearing design, pump housing design, and magnetic coupling force helped to minimize the hemolysis and thrombi formation, prolonging the survival duration of the Shiba goats to 2 weeks with minimum adverse effects on the blood components and organ functions. With further experiments and improvements in pump durability and hemocompatibility, the TinyPump can serve as a suitable circulatory support device for neonates and infants bridging to heart transplantation as well as to heart recovery.
Assuntos
Materiais Biocompatíveis , Coração Auxiliar , Miniaturização , Função Ventricular Esquerda , Animais , Fenômenos Biomecânicos , Peso Corporal , Estudos de Viabilidade , Feminino , Coração Auxiliar/efeitos adversos , Hemodinâmica , Hemólise , Humanos , Hidrodinâmica , Recém-Nascido , Magnetismo , Masculino , Teste de Materiais , Modelos Animais , Desenho de Prótese , Trombose/etiologia , Trombose/prevenção & controle , Fatores de TempoRESUMO
Background: Japanese herbal medicine, called Kampo medicine, and acupuncture are mainly used in Japanese traditional medicine. In this experiment, the analgesic effect of Yokukansan (YKS) alone and a combination of YKS and electroacupuncture (EA) on inflammatory pain induced by formalin injection were examined. Methods: Animals were divided into four groups: a control group, formalin injection group (formalin), YKS-treated formalin group (YKS), and YKS- and EA-treated formalin group (YKS + EA). The duration of pain-related behaviors and extracellular signal-regulated protein kinase (ERK) activation in the spinal cord after formalin injection in the right hind paw were determined. Results: The duration of pain-related behaviors was dramatically prolonged in the late phase (10-60 min) in the formalin group. The YKS treatment tended to reduce (p = 0.08), whereas YKS + EA significantly suppressed the pain-related behaviors (p < 0.01). Immunohistochemical and Western blot analyses revealed that the number of phosphorylated ERK1/2 (pERK1/2)-positive cells and the pERK expression level, which were increased by formalin injection, were significantly inhibited by YKS (p < 0.05) and YKS + EA (p < 0.01). Conclusions: The YKS + EA combination therapy elicited an analgesic effect on formalin-induced acute inflammatory pain.