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1.
Math Biosci Eng ; 21(1): 346-368, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38303426

RESUMO

In response to the limited detection ability and low model generalization ability of the YOLOv7 algorithm for small targets, this paper proposes a detection algorithm based on the improved YOLOv7 algorithm for steel surface defect detection. First, the Transformer-InceptionDWConvolution (TI) module is designed, which combines the Transformer module and InceptionDWConvolution to increase the network's ability to detect small objects. Second, the spatial pyramid pooling fast cross-stage partial channel (SPPFCSPC) structure is introduced to enhance the network training performance. Third, a global attention mechanism (GAM) attention mechanism is designed to optimize the network structure, weaken the irrelevant information in the defect image, and increase the algorithm's ability to detect small defects. Meanwhile, the Mish function is used as the activation function of the feature extraction network to improve the model's generalization ability and feature extraction ability. Finally, a minimum partial distance intersection over union (MPDIoU) loss function is designed to locate the loss and solve the mismatch problem between the complete intersection over union (CIoU) prediction box and the real box directions. The experimental results show that on the Northeastern University Defect Detection (NEU-DET) dataset, the improved YOLOv7 network model improves the mean Average precision (mAP) performance by 6% when compared to the original algorithm, while on the VOC2012 dataset, the mAP performance improves by 2.6%. These results indicate that the proposed algorithm can effectively improve the small defect detection performance on steel surface defects.

2.
Heliyon ; 10(4): e25861, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38384504

RESUMO

Objective: Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease associated with a high incidence of complications in the mid and late stages of gestation. This study investigates differences in the composition of intestinal flora among pregnant women diagnosed with ICP, employing Illumina MiSeq high-throughput sequencing technology. Methods: This case-control study obtained patient data from the hospital information system (HIS) and the laboratory information system (LIS). Fecal samples were collected from 25 pregnant women who did not undergo intestinal preparation before delivery between December 2020 and March 2021. Whole-genome analysis was performed. PCR was used to amplify the 16S rRNA V3-V4 variable region, which was then sequenced. Alpha and beta diversity were computed, and the maternal intestinal flora's abundance and composition characteristics were analyzed. Differences in intestinal flora between the two sample groups were examined. Results: Bacteroides and Proteobacteria exhibited positive correlations with TBIL and IBIL. Betaproteobacteria, Gammaproteobacteria, and Erysipeiotrichi showed positive correlations with TBIL, IBIL, and DBIL, while Lactobacillus, Delftia, and Odoribacter demonstrated positive correlations with ALT. Conclusion: The ICP group displayed significantly higher levels of total bile acid and ALT compared to the control group. The intestinal flora composition comprised four primary phyla: Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. ICP patients exhibited a lower relative abundance of intestinal flora across different levels of community composition when compared to the control group. Specific correlations between certain intestinal flora and clinical liver parameters were identified.

3.
BMC Anesthesiol ; 23(1): 248, 2023 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-37481510

RESUMO

BACKGROUND: Various approaches using epidural analgesia have been employed for relieving labor pain and promoting spontaneous delivery. We aimed to evaluate the effect of nalbuphine and ropivacaine versus fentanyl and ropivacaine on the duration of delivery in parturients. METHODS: Clinical data of 160 full-term primiparous women who received either nalbuphine or fentanyl in combination with ropivacaine infusion for epidural labor analgesia in our hospital from December 2020 to May 2022 were retrospectively analyzed. The participants were divided into two groups based on anesthesia methods: nalbuphine group (NR group, n = 78) received 0.2 mg/mL nalbuphine combined with 0.1% ropivacaine hydrochloride for patient-controlled epidural analgesia (PCEA) and fentanyl group (FR group, n = 82) received 2 ug/mL fentanyl citrate and 0.1% ropivacaine hydrochloride for PCEA. Both groups received an epidural blockade for labor analgesia at lumbar 2-3 interspace. The duration of the first, second, and third stages of labor, the onset of analgesia, and time before delivery (T0), 15 min of analgesia (T1), 30 min of analgesia (T2), full opening of the uterine opening (T3),exerts force during childbirth(T4), heart rate (HR), blood pressure (BP), blood saturation (SpO2), visual analogue pain scale (VAS) score, Ramsay sedation score, and modified Bromage score, and 5 min were recorded at 2 h postpartum (T5). The neonatal Apgar score, neonatal behavioral neurological assessment (NBNA) score, maternal nausea, vomiting, and itchy skin were recorded. RESULTS: Compared with the FR group, the first stage of labor duration (p < 0.05) and total duration of labor (p < 0.05) were shortened and the onset of analgesia (p < 0.05) was increased in the NR group. NR group had lower incidence of urinary retention than FR group (p < 0.05). The maternal and neonatal investigational parameters and scores had no significant difference between the two groups. CONCLUSIONS: Nalbuphine combined with ropivacaine in epidural block labor has a faster onset of analgesia and has a lower incidence of urinary retention than fentanyl combined with ropivacaine, and nalbuphine shortens the duration of the first and total stages of labor. Both nalbuphine and fentanyl can reduce pain during labor, have little effect on maternal hemodynamics, and have no significant effect on neonatal Apgar or NBNA scores.


Assuntos
Analgesia Epidural , Nalbufina , Retenção Urinária , Gravidez , Recém-Nascido , Feminino , Humanos , Ropivacaina , Estudos Retrospectivos , Dor , Fentanila
4.
Br J Haematol ; 201(5): 982-994, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36872867

RESUMO

Beta-thalassaemia is an inherited haemoglobin disorder characterised by ineffective erythropoiesis (IE). The detailed pathogenesis of IE remains unclear. In this study, we used single-cell RNA sequencing (scRNA-seq) to examine IE in Th3/+ ß-thalassaemic mice. The results showed that the erythroid group was remarkably expanded, and genes involved in biological processes such as iron metabolism, haeme synthesis, protein folding, and response to heat were significantly upregulated from erythroid progenitors to reticulocytes in ß-thalassaemic mice. In particular, we identified a unique cell population close to reticulocytes, named ThReticulocytes, characterised by a high level of heat shock protein 70 (Hsp70) expression and dysregulation of iron metabolism and haeme synthesis signalling. Treatment of ß-thalassaemic mice with the haeme oxygenase inhibitor tin-mesoporphyrin effectively improved the iron disorder and IE, and the ThReticulocyte population and Hsp70 expression were significantly suppressed. This study revealed in detail the progression of IE at the single-cell level and possibly provided clues to find therapeutic targets in thalassaemia.


Assuntos
Talassemia , Talassemia beta , Camundongos , Animais , Talassemia beta/metabolismo , Eritropoese , Reticulócitos/metabolismo , Ferro/metabolismo
5.
Hepatobiliary Pancreat Dis Int ; 22(5): 498-503, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35534341

RESUMO

BACKGROUND: Remote ischemic perconditioning (RIPerC) has been demonstrated to protect grafts from hepatic ischemia-reperfusion injury (IRI). This study investigated the role of exosomes in RIPerC of liver grafts in rats. METHODS: Twenty-five rats (including 10 donors) were randomly divided into five groups (n = 5 each group): five rats were used as sham-operated controls (Sham), ten rats were for orthotopic liver transplantation (OLT, 5 donors and 5 recipients) and ten rats were for OLT + RIPerC (5 donors and 5 recipients). Liver architecture and function were evaluated. RESULTS: Compared to the OLT group, the OLT + RIPerC group exhibited significantly improved liver graft histopathology and liver function (P < 0.05). Furthermore, the number of exosomes and the level of P-Akt were increased in the OLT + RIPerC group. CONCLUSIONS: RIPerC effectively improves graft architecture and function, and this protective effect may be related to the increased number of exosomes. The upregulation of P-Akt may be involved in underlying mechanisms.


Assuntos
Exossomos , Transplante de Fígado , Traumatismo por Reperfusão , Ratos , Animais , Transplante de Fígado/efeitos adversos , Proteínas Proto-Oncogênicas c-akt , Exossomos/patologia , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/prevenção & controle , Traumatismo por Reperfusão/patologia , Isquemia , Fígado/cirurgia , Fígado/patologia , Reperfusão
6.
J Biol Chem ; 299(1): 102767, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36470422

RESUMO

PKA-mediated phosphorylation of sarcomeric proteins enhances heart muscle performance in response to ß-adrenergic stimulation and is associated with accelerated relaxation and increased cardiac output for a given preload. At the cellular level, the latter translates to a greater dependence of Ca2+ sensitivity and maximum force on sarcomere length (SL), that is, enhanced length-dependent activation. However, the mechanisms by which PKA phosphorylation of the most notable sarcomeric PKA targets, troponin I (cTnI) and myosin-binding protein C (cMyBP-C), lead to these effects remain elusive. Here, we specifically altered the phosphorylation level of cTnI in heart muscle cells and characterized the structural and functional effects at different levels of background phosphorylation of cMyBP-C and with two different SLs. We found Ser22/23 bisphosphorylation of cTnI was indispensable for the enhancement of length-dependent activation by PKA, as was cMyBP-C phosphorylation. This high level of coordination between cTnI and cMyBP-C may suggest coupling between their regulatory mechanisms. Further evidence for this was provided by our finding that cardiac troponin (cTn) can directly interact with cMyBP-C in vitro, in a phosphorylation- and Ca2+-dependent manner. In addition, bisphosphorylation at Ser22/Ser23 increased Ca2+ sensitivity at long SL in the presence of endogenously phosphorylated cMyBP-C. When cMyBP-C was dephosphorylated, bisphosphorylation of cTnI increased Ca2+ sensitivity and decreased cooperativity at both SLs, which may translate to deleterious effects in physiological settings. Our results could have clinical relevance for disease pathways, where PKA phosphorylation of cTnI may be functionally uncoupled from cMyBP-C phosphorylation due to mutations or haploinsufficiency.


Assuntos
Proteínas de Transporte , Proteínas Quinases Dependentes de AMP Cíclico , Miofibrilas , Troponina I , Cálcio/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Miocárdio/metabolismo , Miofibrilas/metabolismo , Fosforilação , Troponina I/metabolismo , Proteínas de Transporte/metabolismo
7.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 39(12): 1339-1343, 2022 Dec 10.
Artigo em Chinês | MEDLINE | ID: mdl-36453955

RESUMO

OBJECTIVE: To detect variants of IVD gene among 4 neonates with suspected isovalerate acidemia in order to provide a guidance for clinical treatment. METHODS: 111 986 newborns and 7461 hospitalized children with suspected metabolic disorders were screened for acyl carnitine by tandem mass spectrometry. Those showing a significant increase in serum isovaleryl carnitine (C5) were analyzed for urinary organic acid and variants of the IVD gene. RESULTS: Four cases of isovalerate acidemia were detected, which included 2 asymptomatic newborns (0.018‰, 2/111 986) and 2 children suspected for metabolic genetic diseases (0.268‰, 2/7461). The formers had no obvious clinical symptoms. Analysis of acyl carnitine has suggested a significant increase in C5, and urinary organic acid analysis has shown an increase in isovaleryl glycine and 3-hydroxyisovalerate. Laboratory tests of the two hospitalized children revealed high blood ammonia, hyperglycemia, decreased red blood cells, white blood cells, platelets and metabolic acidosis. The main clinical manifestations have included sweaty foot-like odor, feeding difficulty, confusion, drowsiness, and coma. Eight variants (5 types) were detected, which included c.158G>A (p.Arg53His), c.214G>A (p.Asp72Asn), c.548C>T (p.Ala183Val), c.757A>G (p.Thr253Ala) and 1208A>G (p.Tyr403Cys). Among these, c.548C>T and c.757A>G were unreported previously. None of the variants was detected by next generation sequencing of 2095 healthy newborns, and all variants were predicted to be likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics. CONCLUSION: The incidence of isovalerate acidemia in Liuzhou area is quite high. Screening of metabolic genetic diseases is therefore recommended for newborns with abnormal metabolism. The discovery of novel variants has enriched the mutational spectrum of the IVD gene.


Assuntos
Acidose , Recém-Nascido , Criança , Humanos , Carnitina , Eritrócitos , Sequenciamento de Nucleotídeos em Larga Escala
9.
Front Aging Neurosci ; 13: 757823, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34867286

RESUMO

Background: Frail older adults have an increased risk of adverse health outcomes and premature death. They also exhibit altered gait characteristics in comparison with healthy individuals. Methods: In this study, we created a Fried's frailty phenotype (FFP) labelled casual walking video set of older adults based on the West China Health and Aging Trend study. A series of hyperparameters in machine vision models were evaluated for body key point extraction (AlphaPose), silhouette segmentation (Pose2Seg, DPose2Seg, and Mask R-CNN), gait feature extraction (Gaitset, LGaitset, and DGaitset), and feature classification (AlexNet and VGG16), and were highly optimised during analysis of gait sequences of the current dataset. Results: The area under the curve (AUC) of the receiver operating characteristic (ROC) at the physical frailty state identification task for AlexNet was 0.851 (0.827-0.8747) and 0.901 (0.878-0.920) in macro and micro, respectively, and was 0.855 (0.834-0.877) and 0.905 (0.886-0.925) for VGG16 in macro and micro, respectively. Furthermore, this study presents the machine vision method equipped with better predictive performance globally than age and grip strength, as well as than 4-m-walking-time in healthy and pre-frailty classifying. Conclusion: The gait analysis method in this article is unreported and provides promising original tool for frailty and pre-frailty screening with the characteristics of convenience, objectivity, rapidity, and non-contact. These methods can be extended to any gait-related disease identification processes, as well as in-home health monitoring.

10.
Chem Commun (Camb) ; 56(22): 3293-3296, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32073080

RESUMO

Direct C-H functionalization of aryl ethers remains challenging owing to their low reactivity and selectivity. Herein, a novel strategy for nondirected C-H alkenylation of aryl ethers promoted by a dual ligand catalyst was demonstrated. This catalytic system readily achieved the highly efficient alkenylation of alkyl aryl ethers (anisole, phenetole, n-propyl phenyl ether, n-butyl phenyl ether and benzyl phenyl ether), cyclic aryl ethers (1,4-benzodioxan, 2,3-dihydrobenzofuran, dibenzofuran), and diphenyl oxides. Moreover, the proposed methodology was successfully employed for the late-stage modification of complex drugs containing the aryl ether motif. Interestingly, the compounds developed herein displayed fluorescent properties, which would facilitate their biological applications.

11.
J Biol Chem ; 295(14): 4398-4410, 2020 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-32086378

RESUMO

Heart muscle contractility and performance are controlled by posttranslational modifications of sarcomeric proteins. Although myosin regulatory light chain (RLC) phosphorylation has been studied extensively in vitro and in vivo, the precise role of cardiac myosin light chain kinase (cMLCK), the primary kinase acting upon RLC, in the regulation of cardiomyocyte contractility remains poorly understood. In this study, using recombinantly expressed and purified proteins, various analytical methods, in vitro and in situ kinase assays, and mechanical measurements in isolated ventricular trabeculae, we demonstrate that human cMLCK is not a dedicated kinase for RLC but can phosphorylate other sarcomeric proteins with well-characterized regulatory functions. We show that cMLCK specifically monophosphorylates Ser23 of human cardiac troponin I (cTnI) in isolation and in the trimeric troponin complex in vitro and in situ in the native environment of the muscle myofilament lattice. Moreover, we observed that human cMLCK phosphorylates rodent cTnI to a much smaller extent in vitro and in situ, suggesting species-specific adaptation of cMLCK. Although cMLCK treatment of ventricular trabeculae exchanged with rat or human troponin increased their cross-bridge kinetics, the increase in sensitivity of myofilaments to calcium was significantly blunted by human TnI, suggesting that human cTnI phosphorylation by cMLCK modifies the functional consequences of RLC phosphorylation. We propose that cMLCK-mediated phosphorylation of TnI is functionally significant and represents a critical signaling pathway that coordinates the regulatory states of thick and thin filaments in both physiological and potentially pathophysiological conditions of the heart.


Assuntos
Contração Miocárdica/fisiologia , Miocárdio/metabolismo , Quinase de Cadeia Leve de Miosina/metabolismo , Troponina I/metabolismo , Animais , Cálcio/metabolismo , Humanos , Masculino , Miofibrilas/metabolismo , Cadeias Leves de Miosina/química , Cadeias Leves de Miosina/metabolismo , Quinase de Cadeia Leve de Miosina/química , Quinase de Cadeia Leve de Miosina/genética , Peptídeos/análise , Peptídeos/química , Fosforilação , Ratos , Ratos Wistar , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Transdução de Sinais , Troponina I/química , Troponina I/genética
12.
Proc Natl Acad Sci U S A ; 116(31): 15485-15494, 2019 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-31308242

RESUMO

The heart's response to varying demands of the body is regulated by signaling pathways that activate protein kinases which phosphorylate sarcomeric proteins. Although phosphorylation of cardiac myosin binding protein-C (cMyBP-C) has been recognized as a key regulator of myocardial contractility, little is known about its mechanism of action. Here, we used protein kinase A (PKA) and Cε (PKCε), as well as ribosomal S6 kinase II (RSK2), which have different specificities for cMyBP-C's multiple phosphorylation sites, to show that individual sites are not independent, and that phosphorylation of cMyBP-C is controlled by positive and negative regulatory coupling between those sites. PKA phosphorylation of cMyBP-C's N terminus on 3 conserved serine residues is hierarchical and antagonizes phosphorylation by PKCε, and vice versa. In contrast, RSK2 phosphorylation of cMyBP-C accelerates PKA phosphorylation. We used cMyBP-C's regulatory N-terminal domains in defined phosphorylation states for protein-protein interaction studies with isolated cardiac native thin filaments and the S2 domain of cardiac myosin to show that site-specific phosphorylation of this region of cMyBP-C controls its interaction with both the actin-containing thin and myosin-containing thick filaments. We also used fluorescence probes on the myosin-associated regulatory light chain in the thick filaments and on troponin C in the thin filaments to monitor structural changes in the myofilaments of intact heart muscle cells associated with activation of myocardial contraction by the N-terminal region of cMyBP-C in its different phosphorylation states. Our results suggest that cMyBP-C acts as a sarcomeric integrator of multiple signaling pathways that determines downstream physiological function.


Assuntos
Proteínas de Transporte/metabolismo , Miocárdio/metabolismo , Miofibrilas/metabolismo , Actomiosina/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Transporte/química , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Modelos Biológicos , Miosinas/metabolismo , Fosforilação , Proteína Quinase C-épsilon/metabolismo , Ratos
13.
Commun Biol ; 2: 188, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31123712

RESUMO

Human soluble epoxide hydrolase (hsEH) is an enzyme responsible for the inactivation of bioactive epoxy fatty acids, and its inhibition is emerging as a promising therapeutical strategy to target hypertension, cardiovascular disease, pain and insulin sensitivity. Here, we uncover the molecular bases of hsEH inhibition mediated by the endogenous 15-deoxy-Δ12,14-Prostaglandin J2 (15d-PGJ2). Our data reveal a dual inhibitory mechanism, whereby hsEH can be inhibited by reversible docking of 15d-PGJ2 in the catalytic pocket, as well as by covalent locking of the same compound onto cysteine residues C423 and C522, remote to the active site. Biophysical characterisations allied with in silico investigations indicate that the covalent modification of the reactive cysteines may be part of a hitherto undiscovered allosteric regulatory mechanism of the enzyme. This study provides insights into the molecular modes of inhibition of hsEH epoxy-hydrolytic activity and paves the way for the development of new allosteric inhibitors.


Assuntos
Epóxido Hidrolases/antagonistas & inibidores , Prostaglandina D2/análogos & derivados , Regulação Alostérica , Sequência de Aminoácidos , Substituição de Aminoácidos , Domínio Catalítico/genética , Cristalografia por Raios X , Cisteína/química , Inibidores Enzimáticos/farmacologia , Estabilidade Enzimática/efeitos dos fármacos , Epóxido Hidrolases/química , Epóxido Hidrolases/genética , Humanos , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Prostaglandina D2/farmacologia , Domínios Proteicos , Alinhamento de Sequência , Solubilidade
14.
J Biol Chem ; 293(37): 14270-14275, 2018 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-30082313

RESUMO

Myosin-binding protein-C (cMyBP-C) is a key regulator of contractility in heart muscle, and its regulatory function is controlled in turn by phosphorylation of multiple serines in its m-domain. The structural and functional effects of m-domain phosphorylation have often been inferred from those of the corresponding serine-to-aspartate (Ser-Asp) substitutions, in both in vivo and in vitro studies. Here, using a combination of in vitro binding assays and in situ structural and functional assays in ventricular trabeculae of rat heart and the expressed C1mC2 region of cMyBP-C, containing the m-domain flanked by domains C1 and C2, we tested whether these substitutions do in fact mimic the effects of phosphorylation. In situ changes in thin and thick filament structure were determined from changes in polarized fluorescence from bifunctional probes attached to troponin C or myosin regulatory light chain, respectively. We show that both the action of exogenous C1mC2 to activate contraction in the absence of calcium and the accompanying change in thin filament structure are abolished by tris-phosphorylation of the m-domain, but unaffected by the corresponding Ser-Asp substitutions. The latter produced an intermediate change in thick filament structure. Both tris-phosphorylation and Ser-Asp substitutions abolished the interaction between C1mC2 and myosin sub-fragment 2 (myosin S2) in vitro, but yielded different effects on thin filament binding. These results suggest that some previous inferences from the effects of Ser-Asp substitutions in cMyBP-C should be reconsidered and that the distinct effects of tris-phosphorylation and Ser-Asp substitutions on cMyBP-C may provide a useful basis for future studies.


Assuntos
Substituição de Aminoácidos , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Músculos/metabolismo , Miocárdio/metabolismo , Sequência de Aminoácidos , Animais , Ácido Aspártico/genética , Ácido Aspártico/metabolismo , Cálcio/metabolismo , Proteínas de Transporte/genética , Cinética , Masculino , Miosinas/química , Miosinas/metabolismo , Fosforilação , Ligação Proteica , Ratos , Ratos Wistar , Serina/genética , Serina/metabolismo
15.
Org Biomol Chem ; 16(25): 4628-4632, 2018 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-29901667

RESUMO

In this study, a single fluorescent probe (DPFP) containing a 1,8-naphthalimide dye and a homoallylamino group for imaging pH and formaldehyde (FA) has been developed that exhibits significant blue fluorescence (λem at 455 nm) under acidic pH conditions (pH < 7.0) and green fluorescence (λem at 555 nm) in the presence of FA, respectively. Furthermore, probe DPFP was successfully applied to image acidic lysosomes and exogenous or endogenous FA in living HeLa cells.

16.
Biochemistry ; 57(15): 2256-2265, 2018 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-29558109

RESUMO

The development of calcium sensitizers for the treatment of systolic heart failure presents difficulties, including judging the optimal efficacy and the specificity to target cardiac muscle. The thin filament is an attractive target because cardiac troponin C (cTnC) is the site of calcium binding and the trigger for subsequent contraction. One widely studied calcium sensitizer is levosimendan. We have recently shown that when a covalent cTnC-levosimendan analogue is exchanged into cardiac muscle cells, they become constitutively active, demonstrating the potency of a covalent complex. We have also demonstrated that levosimendan reacts in vitro to form a reversible covalent thioimidate bond specifically with cysteine 84, unique to cTnC. In this study, we use mass spectrometry to show that the in vitro mechanism of action of levosimendan is consistent with an allosteric, reversible covalent inhibitor; to determine whether the presence of the cTnI switch peptide or changes in either Ca2+ concentration or pH modify the reaction kinetics; and to determine whether the reaction can occur with cTnC in situ in cardiac myofibrils. Using the derived kinetic rate constants, we predict the degree of covalently modified cTnC in vivo under the conditions studied. We observe that covalent bond formation would be highest under the acidotic conditions resulting from ischemia and discuss whether the predicted level could be sufficient to have therapeutic value. Irrespective of the in vivo mechanism of action for levosimendan, our results provide a rationale and basis for the development of reversible covalent drugs to target the failing heart.


Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Hidrazonas , Isquemia Miocárdica , Miofibrilas , Piridazinas , Troponina C , Animais , Cisteína/metabolismo , Humanos , Hidrazonas/química , Hidrazonas/farmacocinética , Hidrazonas/farmacologia , Concentração de Íons de Hidrogênio , Isquemia Miocárdica/metabolismo , Isquemia Miocárdica/patologia , Miofibrilas/química , Miofibrilas/metabolismo , Miofibrilas/ultraestrutura , Piridazinas/química , Piridazinas/farmacocinética , Piridazinas/farmacologia , Simendana , Suínos , Troponina C/química , Troponina C/metabolismo
17.
J Physiol ; 596(1): 31-46, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29052230

RESUMO

KEY POINTS: Omecamtiv mecarbil and blebbistatin perturb the regulatory state of the thick filament in heart muscle. Omecamtiv mecarbil increases contractility at low levels of activation by stabilizing the ON state of the thick filament. Omecamtiv mecarbil decreases contractility at high levels of activation by disrupting the acto-myosin ATPase cycle. Blebbistatin reduces contractility by stabilizing the thick filament OFF state and inhibiting acto-myosin ATPase. Thick filament regulation is a promising target for novel therapeutics in heart disease. ABSTRACT: Contraction of heart muscle is triggered by a transient rise in intracellular free calcium concentration linked to a change in the structure of the actin-containing thin filaments that allows the head or motor domains of myosin from the thick filaments to bind to them and induce filament sliding. It is becoming increasingly clear that cardiac contractility is also regulated through structural changes in the thick filaments, although the molecular mechanisms underlying thick filament regulation are still relatively poorly understood. Here we investigated those mechanisms using small molecules - omecamtiv mecarbil (OM) and blebbistatin (BS) - that bind specifically to myosin and respectively activate or inhibit contractility in demembranated cardiac muscle cells. We measured isometric force and ATP utilization at different calcium and small-molecule concentrations in parallel with in situ structural changes determined using fluorescent probes on the myosin regulatory light chain in the thick filaments and on troponin C in the thin filaments. The results show that BS inhibits contractility and actin-myosin ATPase by stabilizing the OFF state of the thick filament in which myosin head domains are more parallel to the filament axis. In contrast, OM stabilizes the ON state of the thick filament, but inhibits contractility at high intracellular calcium concentration by disrupting the actin-myosin ATPase pathway. The effects of BS and OM on the calcium sensitivity of isometric force and filament structural changes suggest that the co-operativity of calcium activation in physiological conditions is due to positive coupling between the regulatory states of the thin and thick filaments.


Assuntos
Miosinas Cardíacas/fisiologia , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Contração Miocárdica , Miocárdio/metabolismo , Miócitos Cardíacos/fisiologia , Ureia/análogos & derivados , Citoesqueleto de Actina/metabolismo , Animais , Cálcio/metabolismo , Masculino , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Ratos , Ratos Wistar , Transdução de Sinais , Ureia/farmacologia
18.
Clin Chim Acta ; 475: 78-84, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29037841

RESUMO

BACKGROUND: To investigate the etiology of X-linked hypohidrotic ectodermal dysplasia (XLHED) in a family with an inversion of the X chromosome [inv(X)(p21q13)] and to achieve a healthy birth following preimplantation genetic diagnosis (PGD). METHODS: Next generation sequencing (NGS) and Sanger sequencing analysis were carried out to define the inversion breakpoint. Multiple displacement amplification, amplification of breakpoint junction fragments, Sanger sequencing of exon 1 of ED1, haplotyping of informative short tandem repeat markers and gender determination were performed for PGD. RESULTS: NGS data of the proband sample revealed that the size of the possible inverted fragment was over 42Mb, spanning from position 26, 814, 206 to position 69, 231, 915 on the X chromosome. The breakpoints were confirmed by Sanger sequencing. A total of 5 blastocyst embryos underwent trophectoderm biopsy. Two embryos were diagnosed as carriers and three were unaffected. Two unaffected blastocysts were transferred and a singleton pregnancy was achieved. Following confirmation by prenatal diagnosis, a healthy baby was delivered. CONCLUSIONS: This is the first report of an XLHED family with inv(X). ED1 is disrupted by the X chromosome inversion in this XLHED family and embryos with the X chromosomal abnormality can be accurately identified by means of PGD.


Assuntos
Inversão Cromossômica , Cromossomos Humanos X/química , Displasia Ectodérmica Anidrótica Tipo 1/diagnóstico , Displasia Ectodérmica Anidrótica Tipo 1/prevenção & controle , Ectodisplasinas/genética , Diagnóstico Pré-Implantação/métodos , Adulto , Sequência de Bases , Blastocisto/citologia , Blastocisto/metabolismo , Pontos de Quebra do Cromossomo , Displasia Ectodérmica Anidrótica Tipo 1/genética , Displasia Ectodérmica Anidrótica Tipo 1/patologia , Implantação do Embrião , Éxons , Feminino , Fertilização in vitro , Expressão Gênica , Marcadores Genéticos , Haplótipos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Recém-Nascido , Cariotipagem , Masculino , Repetições de Microssatélites , Linhagem , Gravidez
19.
ACS Appl Mater Interfaces ; 9(37): 32054-32064, 2017 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-28853856

RESUMO

The recent booming development of wearable electronics urgently calls for high-performance flexible strain sensors. To date, it is still a challenge to manufacture flexible strain sensors with superb sensitivity and a large workable strain range simultaneously. Herein, a facile, quick, cost-effective, and scalable strategy is adopted to fabricate novel strain sensors based on reduced graphene oxide woven fabrics (GWF). By pyrolyzing commercial cotton bandages coated with graphene oxide (GO) sheets in an ethanol flame, the reduction of GO and the pyrolysis of the cotton bandage template can be synchronously completed in tens of seconds. Due to the unique hierarchical structure of the GWF, the strain sensor based on GWF exhibits large stretchability (57% strain) with high sensitivity, inconspicuous drift, and durability. The GWF strain sensor is successfully used to monitor full-range (both subtle and vigorous) human activities or physical vibrational signals of the local environment. The present work offers an effective strategy to rapidly prepare low-cost flexible strain sensors with potential applications in the fields of wearable electronics, artificial intelligence devices, and so forth.

20.
Am J Reprod Immunol ; 78(2)2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28508475

RESUMO

CD8+ T cells are the main candidates to recognize and respond to fetal HLA-C at the fetal-maternal interface, but data on the amount of peripheral CD8+ T cells and their functions during the window of implantation in recurrent implantation failure (RIF) patients are limited. Peripheral blood was obtained from 56 women with RIF and 16 fertile women in the mid-luteal phase of the menstrual cycle, and the CD8+ T cells were determined by FACS analysis. No statistical differences in the proportion of peripheral CD8+ T cells were observed among the women with RIF and the control group. However, the levels of IFN-γ+ and TNF-α+ CD8+ T cells in the RIF group were significantly higher than those in the control group. The cytolytic activity and regulatory proportion of CD8+ T cells in RIF were similar to that in the control group. Our data indicated that the elevated expression levels of IFN-γ and TNF-α in peripheral CD8+ T cells may contribute to an impaired immune tolerance in women with RIF.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Implantação do Embrião/imunologia , Infertilidade Feminina/imunologia , Adulto , Feminino , Humanos , Tolerância Imunológica , Interferon gama/imunologia , Fator de Necrose Tumoral alfa/imunologia
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