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In addition to responding to environmental entrainment with diurnal variation, metabolism is also tightly controlled by cell-autonomous circadian clock. Extensive studies have revealed key roles of transcription in circadian control. Post-transcriptional regulation for the rhythmic gating of metabolic enzymes remains elusive. Here, we show that arginine biosynthesis and subsequent ureagenesis are collectively regulated by CLOCK (circadian locomotor output cycles kaput) in circadian rhythms. Facilitated by BMAL1 (brain and muscle Arnt-like protein), CLOCK directly acetylates K165 and K176 of argininosuccinate synthase (ASS1) to inactivate ASS1, which catalyzes the rate-limiting step of arginine biosynthesis. ASS1 acetylation by CLOCK exhibits circadian oscillation in human cells and mouse liver, possibly caused by rhythmic interaction between CLOCK and ASS1, leading to the circadian regulation of ASS1 and ureagenesis. Furthermore, we also identified NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 (NDUFA9) and inosine-5'-monophosphate dehydrogenase 2 (IMPDH2) as acetylation substrates of CLOCK. Taken together, CLOCK modulates metabolic rhythmicity by acting as a rhythmic acetyl-transferase for metabolic enzymes.
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Fatores de Transcrição ARNTL/genética , Argininossuccinato Sintase/genética , Proteínas CLOCK/genética , Ritmo Circadiano/genética , Processamento de Proteína Pós-Traducional , Ureia/metabolismo , Fatores de Transcrição ARNTL/metabolismo , Acetilação , Animais , Arginina/biossíntese , Argininossuccinato Sintase/metabolismo , Proteínas CLOCK/metabolismo , Linhagem Celular Tumoral , Relógios Circadianos , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Células HEK293 , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , IMP Desidrogenase/genética , IMP Desidrogenase/metabolismo , Masculino , Camundongos , Camundongos Knockout , Osteoblastos/metabolismo , Osteoblastos/patologia , Transdução de SinaisRESUMO
PURPOSE: T-condylar (T-C) fractures of the distal humerus are rare in children. There is no accepted treatment for such an injury, and there is a lack of reports evaluating the outcome of T-C fractures treated by closed reduction and percutaneous fixation. The aim of this study was to evaluate the feasibility of closed reduction and percutaneous K-wire and screw (CRPKS) fixation in patients with type II and III T-C fractures according to the Toniolo-Wilkins classification modified by Canavese et al. (TWC classification). METHODS: The clinical data of 12 consecutive patients (8 males, 4 females) who were younger than 14 years of age and who had a T-C fracture that was managed by CRPKS were retrospectively evaluated. Fractures were classified according to the TWC classification. The baseline information of the patients, carrying angle (CA) and Mayo Elbow Performance Score (MEPS) were used to evaluate clinical and functional outcomes; related complications were recorded. Statistical analysis was performed. RESULTS: The mean age at the time of injury was 11.6 ± 1.8 years (range, 8-14). The time from injury to surgical treatment was 1.5 ± 1.0 days (range, 0-3), and the mean follow-up duration was 33.7 ± 12.3 months (range, 18-61). Surgery lasted 45.7 ± 7.6 min on average (range, 35-58). All fractures healed in 4.9 ± 1.0 weeks on average (range, 4-7). At the last follow-up visit, the CA was 12.6° ± 5.8° on the injured side and 13.8° ± 1.8° on the uninjured side (p=0.432). The MEPS was 100 (95, 100) on the injured side and 100 (100, 100) on the uninjured side (p=0.194). Three complications were recorded. CONCLUSION: Good functional and radiological outcomes can be expected in pediatric patients with type II and III T-C fractures treated by CRPKS. The technique is relatively simple to perform and has a lower rate of complications.
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Parafusos Ósseos , Fios Ortopédicos , Redução Fechada , Articulação do Cotovelo , Fraturas do Úmero , Humanos , Masculino , Feminino , Criança , Adolescente , Estudos Retrospectivos , Fraturas do Úmero/cirurgia , Articulação do Cotovelo/cirurgia , Articulação do Cotovelo/fisiopatologia , Redução Fechada/métodos , Resultado do Tratamento , Amplitude de Movimento Articular/fisiologia , Fixação Interna de Fraturas/métodos , Fixação Interna de Fraturas/instrumentação , Lesões no Cotovelo , Radiografia/métodosRESUMO
This study evaluated the effects of four highland barley proteins (HBPs), namely, albumin, globulin, gliadin and glutenin, on the short-term retrogradation of highland barley starch (HBS). The findings reveal that HBPs could reduce the viscosity, storage modulus and hardness of HBS, with albumin and globulin showing more prominent effects. Furthermore, with the addition of HBPs, the loss tangent (tan δ) of HBS loss increased from 0.07 to 0.10, and the enthalpy of gelatinization decreased from 8.33 to 7.23. The degree of retrogradation (DR%) of HBS was 5.57%, and the DR% decreased by 26.65%, 38.78%, 11.67% and 20.29% with the addition of albumin, globulin, gliadin and glutenin, respectively. Moreover, the relative crystallinity (RC) and the double helix structures were inhibited with the HBPs' incorporation. Meanwhile, the HBPs also could inhibit water migration and improve the structure of HBS gels. In summary, HBPs could inhibit the retrogradation behavior of HBS, which provides new theoretical insights for the production studies of highland barley foods.
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Globulinas , Hordeum , Amido/química , Gliadina/química , AlbuminasRESUMO
Carbamate is a key structural motif in the development of fungicidal compounds, which is still promising and robust in the discovery of green pesticides. Herein, we report the synthesis and evaluation of the fungicidal activity of 35 carbamate derivatives, among which 19 compounds were synthesized in our previous report. These derivatives were synthesized from aromatic amides in a single step, which was a green oxidation process for Hofmann rearrangement using oxone, KCl and NaOH. Their chemical structures were characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry. Their antifungal activity was tested against seven plant fungal pathogens. Many of the compounds exhibited good antifungal activity in vitro (inhibitory rate > 60% at 50 µg/mL). Compound 1ag exhibited excellent broad-spectrum antifungal activities with inhibition rates close to or higher than 70% at 50 µg/mL. Notably, compound 1af demonstrated the most potent inhibition against F. graminearum, with an EC50 value of 12.50 µg/mL, while compound 1z was the most promising candidate fungicide against F. oxysporum (EC50 = 16.65 µg/mL). The structure-activity relationships are also discussed in this paper. These results suggest that the N-aryl carbamate derivatives secured by our green protocol warrant further investigation as potential lead compounds for novel antifungal agents.
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Antifúngicos , Carbamatos , Química Verde , Testes de Sensibilidade Microbiana , Carbamatos/química , Carbamatos/farmacologia , Carbamatos/síntese química , Antifúngicos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Relação Estrutura-Atividade , Estrutura Molecular , Fungos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Fusarium/efeitos dos fármacosRESUMO
Semipinacol rearrangement is a special type of Wagner-Meerwein rearrangement that involves carbocation 1,2-rearrangement to provide carbonyl compounds with an α-quaternary carbon center. It has been strategically used for natural product synthesis and construction of highly congested quaternary carbons. Herein, we report a safe and green protocol that uses oxone/halide and Fenton bromide to achieve halogenative semipinacol rearrangement. The key feature of this method is the green in situ generation of reactive halogenating species from oxidation of halide with oxone or H2O2, which produces a nontoxic byproduct (potassium sulfate or water). Easy operation (insensitive to air and moisture) at room temperature without using special equipment adds additional advantage over previous methods.
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Cicloexenos , Peróxido de Hidrogênio , CiclizaçãoRESUMO
Chinese mitten crab (Eriocheir sinensis) is an economically important aquaculture species, and its growth and development are regulated by temperature, but the molecular mechanisms of the responses to temperature remain unclear. Herein, we identified TRPA1 from E. sinensis, a member of the TRP family of heat receptor potential channels, performed RACE cloning and bioinformatics analysis, and investigated the effect of TRPA1 on temperature responses and molting by real-time PCR and RNA interference (RNAi). The open reading frame of Es-TRPA1 is 3660 bp, and the encoded protein has a molecular weight of 136.91 kDa, and is expressed in embryos and juveniles. RNAi-mediated silencing decreased Es-TRPA1 expression in juvenile crabs, molting rate was decreased, mortality was increased, and crabs avoided cold areas (4 °C) much less than control juvenile crabs. The results suggest that Es-TRPA1 is involved in regulating temperature adaptation and molting processes in E. sinensis. The findings lay a foundation for further exploration of temperature regulation mechanisms in E. sinensis and other crustaceans.
Assuntos
Braquiúros , Muda , Animais , Sequência de Aminoácidos , Temperatura , Muda/fisiologia , Crustáceos/genética , Clonagem Molecular , Braquiúros/genética , FilogeniaRESUMO
On the basis of the three-component synthetic methodology developed by us, a total of twenty-six pyrazole compounds bearing aryl OCF3 were designed and synthesized. Their chemical structures were characterized by 1H and 13C nuclear magnetic resonance and high-resolution mass spectrometry. These compounds were evaluated systematically for antifungal activities in vitro against six plant pathogenic fungi by the mycelium growth rate method. Most of the compounds showed some activity against each of the fungi at 100 µg/mL. Compounds 1t and 1v exhibited higher activity against all the tested fungi, and 1v displayed the highest activity against F. graminearum with an EC50 value of 0.0530 µM, which was comparable with commercial pyraclostrobin. Structure-activity relationship analysis showed that, with respect to the R1 substituent, the straight chain or cycloalkyl ring moiety was a key structural moiety for the activity, and the R2 substituent on the pyrazole ring could have significant effects on the activity. Simple and readily available pyrazoles with potent antifungal activity were obtained, which are ready for further elaboration to serve as a pharmacophore in new potential antifungal agents.
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Antifúngicos , Pirazóis , Antifúngicos/farmacologia , Pirazóis/farmacologia , Espectrometria de Massas , MicélioRESUMO
A unique benzannulation strategy for regioselective de novo synthesis of densely functionalized phenols is described. Through metal-mediated formal [2+2+1+1] cycloaddition of two different alkynes and two molecules of CO, a series of densely functionalized phenols were obtained. The benzannulation strategy allows efficient regioselective installation up to five different substituents on a phenol ring. The resulting phenols have a substitution pattern different from those obtained from Dötz and Danheiser benzannulations.
RESUMO
In this study, we measure the absolute isotope ratios of ytterbium (Yb) by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) using an optimized regression model for mass bias correction. A rhenium (Re) reference material (NIST SRM 3143), which has been characterized previously, is selected as a primary calibrator to calibrate the absolute Yb isotope ratios for three Yb materials (GSB, Alfa Yb, and GBW). The three-isotope plot for all collected data indicates that the results of Yb isotope ratios obtained are not affected by any polyatomic interferences and the mass-independent isotopic fractionation. Furthermore, the recalibrated Hf historical isotope ratios by using the absolute Yb isotopic composition obtained in this study for the isobaric interference correction on Hf isotopes are in agreement with the original historical values. This work has further demonstrated the applicability of the regression model for the calibrated measurements of absolute isotope ratios using MC-ICP-MS. The three mono-elemental Yb standard solutions are thus proposed as the reference materials for Yb isotope ratio measurements in environmental and geoscience applications.
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Isótopos , Itérbio , Isótopos/análise , Espectrometria de Massas/métodos , Análise EspectralRESUMO
BACKGROUND: Accumulation of myofibroblasts is critical to fibrogenesis in idiopathic pulmonary fibrosis (IPF). Senescence and insufficient mitophagy in fibroblasts contribute to their differentiation into myofibroblasts, thereby promoting the development of lung fibrosis. Bone morphogenetic protein 4 (BMP4), a multifunctional growth factor, is essential for the early stage of lung development; however, the role of BMP4 in modulating lung fibrosis remains unknown. METHODS: The aim of this study was to evaluate the role of BMP4 in lung fibrosis using BMP4-haplodeleted mice, BMP4-overexpressed mice, primary lung fibroblasts and lung samples from patients with IPF. RESULTS: BMP4 expression was downregulated in IPF lungs and fibroblasts compared to control individuals, negatively correlated with fibrotic genes, and BMP4 decreased with transforming growth factor (TGF)-ß1 stimulation in lung fibroblasts in a time- and dose-dependent manner. In mice challenged with bleomycin, BMP4 haploinsufficiency perpetuated activation of lung myofibroblasts and caused accelerated lung function decline, severe fibrosis and mortality. BMP4 overexpression using adeno-associated virus 9 vectors showed preventative and therapeutic efficacy against lung fibrosis. In vitro, BMP4 attenuated TGF-ß1-induced fibroblast-to-myofibroblast differentiation and extracellular matrix (ECM) production by reducing impaired mitophagy and cellular senescence in lung fibroblasts. Pink1 silencing by short-hairpin RNA transfection abolished the ability of BMP4 to reverse the TGF-ß1-induced myofibroblast differentiation and ECM production, indicating dependence on Pink1-mediated mitophagy. Moreover, the inhibitory effect of BMP4 on fibroblast activation and differentiation was accompanied with an activation of Smad1/5/9 signalling and suppression of TGF-ß1-mediated Smad2/3 signalling in vivo and in vitro. CONCLUSION: Strategies for enhancing BMP4 signalling may represent an effective treatment for pulmonary fibrosis.
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Proteína Morfogenética Óssea 4 , Fibrose Pulmonar Idiopática , Animais , Camundongos , Bleomicina/farmacologia , Proteína Morfogenética Óssea 4/metabolismo , Senescência Celular , Fibroblastos/metabolismo , Fibrose Pulmonar Idiopática/genética , Pulmão/metabolismo , Camundongos Endogâmicos C57BL , Mitofagia , Miofibroblastos/metabolismo , Proteínas Quinases/metabolismo , Fator de Crescimento Transformador beta1/metabolismoRESUMO
BACKGROUND: Ulna distraction by monolateral external fixator (MEFix) is a good option for the treatment of Masada type I and IIb deformities in children with hereditary multiple exostoses (HMEs). However, there is no consensus regarding where to perform ulnar osteotomy. Our hypothesis is that osteotomy at the proximal third of the ulna and progressive distraction with MEFix can simultaneously correct elbow and wrist deformities in patients with HME. METHODS: We retrospectively reviewed patients with HME who underwent ulna distraction osteogenesis from June 2014 to March 2019. The carrying angle (CA), radial articular angle (RAA), ulnar variance (UV), radial variance (RV) and range of motion (ROM) of the affected forearm and elbow were clinically assessed before lengthening and at the last follow-up visit. The total ulna lengthening distance (LD) and radiographic outcome were also recorded. RESULTS: Nineteen patients (20 forearms) with HME aged 9.1 ± 2.4 years at the time of surgery were retrospectively reviewed. The mean follow-up period was 26.1 ± 5.6 months. There were 11 patients (12 forearms) with Masada type I deformities and eight patients (8 forearms) with Masada type IIb deformities. Patients with type IIb deformity had higher RV, lower CA values, less elbow flexion and forearm pronosupination than those with type I deformity (p < 0.05); RV was an independent risk factor for radial head dislocation, with the cut off at RV > 15.5 mm. The mean LDs in patients with type I and type IIb deformities were 33.6 ± 6.6 mm and 41.4 ± 5.4 mm, respectively. The mean CA, UV, RV, forearm pronation and ulna deviation at the wrist improved significantly following surgery in all patients. In particular, five of eight patients (62.5%) with type IIb deformities had concentric reduction of the radiocapitellar joint, while no radial head subluxation was detected in patients with type I deformities at the last follow-up. Three complications were recorded: two pin-track infections and one delayed union. CONCLUSIONS: Distraction osteogenesis at the proximal third of the ulna provides satisfactory clinical and radiological outcomes in patients with Masada type I and IIb deformities. Early treatment of Masada type I deformities is indicated before progression to more complex type IIb deformities.
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Exostose Múltipla Hereditária , Luxações Articulares , Osteogênese por Distração , Humanos , Criança , Exostose Múltipla Hereditária/complicações , Exostose Múltipla Hereditária/diagnóstico por imagem , Exostose Múltipla Hereditária/cirurgia , Estudos Retrospectivos , Osteogênese por Distração/efeitos adversos , Ulna/diagnóstico por imagem , Ulna/cirurgia , Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/cirurgia , Antebraço/cirurgia , Luxações Articulares/cirurgia , Resultado do TratamentoRESUMO
Background and Objectives: The femoral neck system (FNS) is a new minimally invasive internal fixation system for femoral neck fractures (FNFs), but its use has not been reported in adolescents. The aim of this study was to compare the clinical and radiographic outcomes of displaced FNF in adolescents treated with FNS or a cannulated compression screw (CCS). Materials and Methods: A retrospective study of 58 consecutive patients with displaced FNF treated surgically was performed; overall, 28 patients underwent FNS and 30 CCS fixation. Sex, age at injury, type of fracture, associated lesions, duration of surgery, radiation exposure, and blood loss were collected from the hospital database. The clinical and radiographic results, as well as complications, were recorded and compared. Results: The patients were followed up for 16.4 ± 3.1 months on average after index surgery (range, 12 to 24). Consolidation time among patients treated with FNS was significantly lower than those managed by CCS (p = 0.000). The functional scores of patients treated with FNS were significantly higher than those managed by CCS (p = 0.030). Unplanned hardware removal in patients treated with FNS was significantly lower than in those managed by CCS (p = 0.024). Conclusions: FNS has a lower complication rate and better functional outcome than CCS. It may be a good alternative to treat femoral neck fractures in adolescents.
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Fraturas do Colo Femoral , Adolescente , Parafusos Ósseos/efeitos adversos , Fraturas do Colo Femoral/cirurgia , Colo do Fêmur/patologia , Colo do Fêmur/cirurgia , Fixação Interna de Fraturas/efeitos adversos , Humanos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Ribosomal frameshifting is an important pathway used by many viruses for protein synthesis that involves mRNA translocation of various numbers of nucleotides. Resolving the mRNA positions with subnucleotide precision will provide critical mechanistic information that is difficult to obtain with current techniques. We report a method of high-resolution DNA rulers with subnucleotide precision and the discovery of new frameshifting intermediate states on mRNA containing a GA7 G motif. Two intermediate states were observed with the aid of fusidic acid, one at the "0" reading frame and the other near the "-1" reading frame, in contrast to the "-2" and "-1" frameshifting products found in the absence of the antibiotic. We termed the new near-"-1" intermediate the Post(-1*) state because it was shifted by approximately half a nucleotide compared to the normal "-1" reading frame at the 5'-end. This indicates a ribosome conformation that is different from the conventional model of three reading frames. Our work reveals uniquely precise mRNA motions and subtle conformational changes that will complement structural and fluorescence studies.
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RNA Mensageiro/metabolismo , Ribossomos/metabolismo , Sequência de Bases , Mudança da Fase de Leitura do Gene Ribossômico , Ácido Fusídico/química , Biossíntese de Proteínas , RNA Mensageiro/química , Fases de Leitura/genéticaRESUMO
Chronic wounds are a common and debilitating condition associated with aging populations that impact more than 6.5 million patients in the United States. We have previously demonstrated the efficacy of daily topical 1% valsartan in treating wounds in diabetic mouse and pig models. Despite these promising results, there remains a need to develop an extended-release formulation that would reduce patient burden by decreasing the frequency of daily applications. Here, we used nanotechnology to self-assemble valsartan amphiphiles into a filamentous structure (val-filaments) that would serve as a scaffold in wound beds and allow for steady, localised and tunable release of valsartan amphiphiles over 24 days. Two topical treatments of this peptide-based hydrogel on full-thickness wounds in Zucker Diabetic Fatty rats resulted in faster rates of wound closure. By day 23, all val-filament treated wounds were completely closed, as compared to one wound closed in the placebo group. Mechanistically, we observed enrichment of proteins involved in cell adhesion and energetics pathways, downregulation of Tgf-ß signalling pathway mediators (pSmad2, pSmad3 and Smad4) and increased mitochondrial metabolic pathway intermediates. This study demonstrates the successful synthesis of a sustained-release valsartan filament hydrogel, its impact on mitochondrial energetics and efficacy in treating diabetic wounds.
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Diabetes Mellitus , Cicatrização , Animais , Humanos , Hidrogéis , Ratos , Ratos Zucker , Valsartana/farmacologiaRESUMO
PURPOSE: To prospectively compare the effectiveness of three methods for self-assisted shoulder reduction demonstrated using a smartphone video link. BACKGROUND: Anterior shoulder dislocation is very common among young adults. Patients often seek medical assistance in the emergency department to reduce their shoulder. Many techniques for shoulder reduction had been described, some of which do not require professional assistance and can be performed by patients themselves. METHODS: Patients admitted with anterior shoulder dislocation were randomized to either the Stimson, Milch or the Boss-Holtzach-Matter technique. Each patient was given a link to watch a short instructional video on his smartphone and instructed to attempt self-reduction. Success of the reduction, pain level, patient satisfaction and complications were recorded. RESULTS: The study cohort consisted of 58 patients (mean age was 31.6 (18-66, median = 27), 82% males, 88% right hand dominant). Success rate using Boss-Holtzach-Matter (10 of 19, 53%) and self-assisted Milch (11 of 20, 55%) were significantly higher than with the self-assisted Stimson method (3 of 19, 16%), p < 0.05. Pain levels improved from 8.4 (2-10) to 3.1 (0-10) following the reduction. Patient subjective satisfaction from the reduction attempt was 6.7 (0-10). No complications were observed. CONCLUSION: Both the Self-assisted Milch and the Boss-Holtzach-Matter techniques are ideal for reduction of anterior shoulder dislocation without medical assistance. Both methods can be successfully performed without assistance or previous education and taught using an instructional video. LEVEL OF EVIDENCE: Level II.
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Manipulação Ortopédica/métodos , Educação de Pacientes como Assunto/métodos , Autocuidado , Luxação do Ombro/terapia , Smartphone , Adolescente , Adulto , Idoso , Estudos de Coortes , Serviço Hospitalar de Emergência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Estudos Prospectivos , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: This retrospective multicenter study investigated whether the presence of free fracture fragments is associated with the clinical outcome of adolescents with Delbet II femoral neck fracture (FNF). MATERIALS AND METHODS: The study population comprised 74 adolescents with Delbet II FNF, with an average age of 13.31 y (range, 10-17 y). There were 19 and 55 patients, respectively, with and without (control) free fracture fragments. The patients underwent open (n = 41) or closed (n = 33) fracture reduction and then cannulated screw internal fixation. Postoperative functional evaluation was performed using Ratliff's criteria, and complications such as femoral head necrosis, premature epiphyseal closure, and coxa vara were recorded. RESULTS: All patients achieved bony union during the mean follow-up period of 15.6 mo (range, 12-78 mo). By Ratliff's criteria, the clinical outcomes of the patients with free fracture fragment (three excellent, eight good, eight poor) were significantly worse compared with the control group (26 excellent, 20 good, and nine poor). The rate of complications (femoral head necrosis, premature epiphyseal closure, and coxa vara) of patients with free fracture fragments was significantly higher than that of the control patients. CONCLUSIONS: In adolescents with Delbet II FNF, the presence of free fracture fragments is associated with poorer clinical outcomes. Delbet II FNF in adolescents with free fracture fragment may be a special clinical entity with a poorer outcome.
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Fraturas do Colo Femoral/complicações , Adolescente , Estudos de Casos e Controles , Criança , Feminino , Fraturas do Colo Femoral/cirurgia , Fixação de Fratura , Humanos , Masculino , Estudos Retrospectivos , Resultado do TratamentoRESUMO
The acyclic organic alkynes and carbyne bonds exhibit linear shapes. Metallabenzynes and metallapentalynes are six- or five-membered metallacycles containing carbynes, whose carbine-carbon bond angles are less than 180°. Such distortion results in considerable ring strain, resulting in the unprecedented reactivity compared with acyclic carbynes. Meanwhile, the aromaticity of these metallacycles would stabilize the ring system. The fascinating combination of ring strain and aromaticity would lead to interesting reactivities. This mini review summarized recent findings on the reactivity of the metal-carbon triple bonds and the aromatic ring system. In the case of metallabenzynes, aromaticity would prevail over ring strain. The reactions are similar to those of organic aromatics, especially in electrophilic reactions. Meanwhile, fragmentation of metallacarbynes might be observed via migratory insertion if the aromaticity of metallacarbynes is strongly affected. In the case of metallapentalynes, the extremely small bond angle would result in high reactivity of the carbyne moiety, which would undergo typical reactions for organic alkynes, including interaction with coinage metal complexes, electrophilic reactions, nucleophilic reactions and cycloaddition reactions, whereas the strong aromaticity ensured the integrity of the bicyclic framework of metallapentalynes throughout all reported reaction conditions.
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Carbamatos/química , Carbamatos/síntese química , Reação de CicloadiçãoRESUMO
During ribosome translocation, the elongation factor EF-G undergoes large conformational change while maintaining its contact with the moving tRNA. We previously measured a power stroke accompanying EF-G catalysis, which was consistent with structural studies. However, the role of power stroke in translocation fidelity remains unclear. Here, we report quantitative measurements of the power strokes of structurally modified EF-Gs by using two different techniques and reveal the correlation between power stroke and translocation efficiency and fidelity. We discovered that the reduced power stroke only lowered the percentage of translocation but did not introduce translocation error. The established force -structure-function correlation for EF-G indicates that power stroke drives ribosomal translocation, but the mRNA reading frame is probably maintained by ribosome itself. Furthermore, the microscope detection method reported here can be simply implemented for other biochemical applications.
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Fator G para Elongação de Peptídeos/química , RNA Mensageiro/química , Ribossomos/química , Sequência de Bases , DNA/química , Escherichia coli/química , Ácido Fusídico/química , Microscopia , Biossíntese de Proteínas , RNA de Transferência/químicaRESUMO
The total synthesis of potent anti-obesity lansiumamide B was accomplished in four steps using commercially available materials. The synthetic strategy, featured with copper-catalyzed Buchwald coupling, is concise, convergent, practical and can be carried out on a one-gram scale. This approach could give either Z- or E-configured enamide moiety in natural products with absolute stereocontrol and was applied in the total synthesis of natural products.
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Fármacos Antiobesidade/síntese química , Produtos Biológicos/síntese química , Cinamatos/síntese química , Fármacos Antiobesidade/química , Produtos Biológicos/química , Catálise , Cinamatos/química , Estrutura Molecular , EstereoisomerismoRESUMO
Objective To investigate the expressions,roles,and clinical significance of microRNA-365(miR-365)and E74-like factor 4(ELF4)in cervical cancer. Methods The expressions of miR-365 in normal cervical tissues(n=34),cervical intraepithelial neoplasia 1(CIN 1)(n=31),cervical intraepithelial neoplasia2-3(CIN 2-3)(n=37),squamous cell carcinoma of the cervix(SCC)(n=33),and three cervical cancer cell lines(C33A cells,Hela cells,and SiHa cells)were detected by real-time quantitative polymerase chain reaction(qPCR).Bioinformatic prediction and luciferase reporter gene assay were performed to verify whether ELF4 was a direct target of miR-365.Western blot and immunohistochemistry were used to detect ELF4 expression in cervical cancer cells and in different pathological cervix tissues.CCK8 assay was used to detect the effect of overexpression or inhibition of miR-365 on the proliferation of cervical cancer cells at different time points.The relationships among the miR-365 expression,ELF4 expression,and clinicopathological parameters of cervical cancer were analyzed by correlation analysis. Results qPCR results showed that compared with the normal cervical cell HcerEpic,the expressions of miR-365 in CIN1,CIN2-3,and cervical cancer tissues gradually decreased with the increased pathologic grade,and its expressions also decreased in different cervical cancer cell lines.The luciferase reporter gene assay confirmed that ELF4 was the direct target of miR-365.Western blot showed that the expression of ELF4 increased in all three cervical cancer cell lines compared with normal cervical epidermal cell(P=0.013,P=0.002,P=0.004).Immunohistochemistry showed that ELF4 expression was up-regulated in CIN and cervical cancer tissues.CCK8 assay showed that overexpression of miR-365 inhibited cell proliferation,while inhibition of miR-365 promoted the proliferation of three cervical cancer cells(P<0.05).Further analysis confirmed that there was a negative correlation between the expression levels of miR-365 and ELF4 in CIN2-3 and SCC(r=-0.351,P=0.045;r=-0.349,P=0.035).Clinical analysis showed that the expressions of both miR-365 and ELF4 were correlated with tumor size,pathological grade,and clinical stage in SCC(all P < 0.05).Conclusion The decreased expression of miR-365 in human cervical cancer cells relieves its inhibitory effect on ELF4,which promotes the proliferation of cervical cancer cells and the formation of tumor.