Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 56
Filtrar
1.
J Phys Condens Matter ; 36(16)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38096589

RESUMO

Single crystals of GaKCu(PO4)2were synthesized using the hydrothermal method, and subsequent measurements of specific heat, magnetic susceptibility, and high-field magnetization were performed. A broad peak is observed in the magnetic susceptibility and specific heat curves, with the maximum values appearing at about 11.5 K and 5.29 K, respectively. The highest maximum peak value of susceptibility is observed when the magnetic field is applied along thec-axis, followed by thea-axis,b-axis, and polycrystalline samples. These indicate that the system exhibits one-dimensional magnetism and the magnetic easy axis is thecaxis. The magnetization at 2 K reveals the occurrence of a field-induced Bose-Einstein condensation (BEC) phase within the magnetic field range of approximately 8-12 T. High-field magnetization up to 40 T indicates that the compound reaches magnetization saturation as the field exceedsHs= 12 T. Through systematic measurements, a field-temperature (H-T) phase diagram was constructed, and dome-like phase boundaries were observed. The findings suggest that GaKCu(PO4)2is a spin gap system and a promising candidate for studying BEC of magnons due to its phase transition boundary occurring at low magnetic fields.

2.
Eur Rev Med Pharmacol Sci ; 27(12): 5445-5452, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37401280

RESUMO

OBJECTIVE: The aim of this study was to investigate the correlation between obstructive sleep apnea (OSA) and otitis media with effusion (OME) in Chinese children and identify risk factors for OME to support the development of standardized diagnostic and treatment methods. PATIENTS AND METHODS: Clinical data of 1,021 children with OSA admitted to our hospital between January 2019 and December 2020 were collected. The prevalence of OME was assessed based on age groups and different grades of adenoid hypertrophy (AH). Multivariate logistic regression was performed to determine risk factors for OME in this population. RESULTS: Among the patients, only 73 (6.15%) reported hearing loss as the main complaint, while 178 (17.43%) were diagnosed with OME after the examination. Acoustic immittance showed higher detection rates for OME compared to those of otoscopy and pure tone audiometry. In addition, the incidence of OME did not increase with AH grade but was higher in children with OSA with AH grade IV. Multivariate regression analysis showed that the younger age group (2-5 years), AH grade IV, nasal inflammatory disease, and passive smoking were significant risk factors for OSA and OME. However, sex, age of 6-12 years, and presence of chronic tonsillitis/tonsillar hypertrophy had no significant impact on the prevalence of OME. CONCLUSIONS: OME is highly prevalent in children with OSA. Clinicians should be vigilant in diagnosing OME, should conduct routine audiological examinations, and actively screen for middle ear fluid in all children with OSA, especially in younger children (2-5 years) with nasal mucosa inflammation and a history of passive smoking. This will help improve the detection rate of OME, as early intervention is paramount for preventing complications.


Assuntos
Otite Média com Derrame , Otite Média , Apneia Obstrutiva do Sono , Poluição por Fumaça de Tabaco , Humanos , Criança , Pré-Escolar , Otite Média com Derrame/diagnóstico , Otite Média com Derrame/epidemiologia , Otite Média com Derrame/complicações , Prevalência , Fatores de Risco , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/epidemiologia , Hipertrofia/epidemiologia , Otite Média/complicações
3.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 58(4): 337-344, 2023 Apr 09.
Artigo em Chinês | MEDLINE | ID: mdl-37005780

RESUMO

Objective: To analyze the flow field characteristics of the upper airway in patients with different adenoid hypertrophy using computational fluid dynamics (CFD). Methods: From November 2020 to November 2021, the cone-beam CT (CBCT) data of 4 patients [2 males and 2 females,age range 5-7 years, mean (6.0±1.2) years] with adenoid hypertrophy who were hospitalized in the Department of Orthodontics and the Department of Otolaryngology at Hebei Eye Hospital were selected. The degree of adenoid hypertrophy in the 4 patients was divided into normal S1 (A/N<0.6), mild hypertrophy S2 (0.6≤A/N<0.7), moderate hypertrophy S3 (0.7≤A/N<0.9) and severe hypertrophy S4 (A/N≥0.9) according to the ratio of adenoid thickness to the width of nasopharyngeal cavity (A/N). The CFD model of the upper airway was established using ANSYS 2019 R1 software, and the internal flow field of the CFD model was numerically simulated. Eight sections were selected as observation and measurement planes for flow field information. Relevant flow field information includes airflow distribution, velocity variation, and pressure variation. Results: In the S1 model, the maximum pressure difference occurred in the 4th and 5th observation planes (ΔP=27.98). The lowest pressures and the maximum flow rates of S2 and S3 were located in the 6th observation plane. The airflow in S1 and S2 models completely passed through the nasal cavity. In the S3 model, the mouth-to-nasal airflow ratio was close to 2∶1. In S4 model, the airflow completely passed through the mouth; in the S1 and S2 models, hard palates were subjected to a downward positive pressure with a pressure difference of 38.34 and 23.31 Pa, respectively. The hard palates in S3 and S4 models were subjected to a downward negative pressure with a pressure difference of -2.95 and -21.81 Pa, respectively. Conclusions: The CFD model can objectively and quantitatively describe the upper airway airflow field information in patients with adenoid hypertrophy. With the increasing degree of adenoid hypertrophy, the nasal ventilation volume gradually decreased, whereas the oral space ventilation volume gradually increased, and the pressure difference between the upper and lower surfaces of the palate gradually decreased until the pressure became negative.

4.
J Phys Condens Matter ; 35(20)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36881910

RESUMO

We report the single-crystal growth of Mn2V2O7and the results of magnetic susceptibility, high-field magnetization up to 55 T and high-frequency electric spin resonance (ESR) measurements for its low-temperatureαphase. Two antiferromagnetic (AFM) ordering at 17.5 K and 3 K and obvious magnetic anisotropy are observed inα-Mn2V2O7upon cooling. In pulsed high magnetic fields, the compound reaches the saturation magnetic moment of ∼10.5µBfor each molecular formula at around 45 T after two undergoing AFM phase transitions atHc1≈ 16 T,Hc2≈ 34.5 T forH//[11-0] andHsf1= 2.5 T,Hsf2= 7 T forH//[001]. In these two directions, two and seven resonance modes are detected by ESR spectroscopy, respectively. Theω1andω2modes ofH//[11-0] can be well described by two-sublattice AFM resonance mode with two zero-field gaps at 94.51 GHz and 169.28 GHz, indicating a hard-axis feature. The seven modes forH//[001] are partially separated by the critical fields ofHsf1andHsf2, displaying the two signs of spin-flop transition. The fittings ofωc1andωc2modes yield zero-field gaps at 69.50 GHz and 84.73 GHz forH//[001], confirming the axis-type anisotropy. The saturated moment and gyromagnetic ratio indicate the Mn2+ion inα-Mn2V2O7is in a high spin state with orbital moment completely quenched. A quasi-one-dimensional magnetism with a zig-zag-chain spin configuration is suggested inα-Mn2V2O7, due to the special neighbor interactions caused by a distorted network structure with honeycomb layer.

5.
Artigo em Inglês | MEDLINE | ID: mdl-35588724

RESUMO

We have grown the high quality single crystals of SrCdBi2successfully and investigated the physical properties systematically through measurements of magnetoresistance, Hall effect, magnetic susceptibility, and specific heat measurements. The compound is a nonmagnetic 112-type pnictide with a Bi square net layer, which is potential for hosting Dirac fermions. We found that it exhibited metallic behavior with an anomaly appearing at around 210 K. Magnetoresistance study reveal that the electronic structure of SrCdBi2is quasi-two-dimensional. At low temperatures, we observed magnetic field induced metal-to-insulator-like transition and resistivity plateau, nonsaturating quasilinear magnetoresistance, and high carrier mobility in magnetotransport measurements, which indicate the possible existence of nearly massless Dirac fermions in SrCdBi2. The anomaly at around 210 K can be observed in resistivity, Hall effect, and magnetic susceptibility, but can't be detected in heat capacity. This implies the anomaly might be caused by domain formation or disorder. We found that the nonsaturating linear magnetoresistance in SrCdBi2is likely caused by both of the quantum linear dispersion and the classical disorder. Our findings suggest that SrCdBi2is a natural experimental platform for realizing the topological properties of nonmagnetic 112-type pnictides.

6.
J Phys Condens Matter ; 33(43)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34343981

RESUMO

In low-dimensional Ising spin systems, an interesting observation is the presence of step magnetization at low temperatures. Here we combine both DC and pulsed magnetic fields to study the 1/3 magnetization plateau and multiple steps in the Ising spin-chain material α-CoV2O6. Magnetization in pulsed fields is quite different from that in DC fields, showing multiple steps in an intermediate range of 4.2-6 K, inverted hysteresis below 4.2 K and asymmetric magnetization in negative fields below 11 K. We demonstrate that these unusual behaviors in magnetization are caused by the spin dynamics and the anomalous magnetocaloric effect (MCE) in α-CoV2O6, i.e., abrupt changes of sample temperature in adiabatic conditions. We successfully separate the influence between the intrinsic slow spin dynamics and the quasi-extrinsic temperature change. From the MCE, we find that some irreversible behavior is originated from the slow spin dynamics. Two different slow dynamics associated with the metastable steps are observed: one is sensitive to the slow field sweep rate at the order of ∼mT s-1and weakly depends on temperature, while the other responds to the rapid field sweep rate of ∼kT s-1and dominates at lowest temperature. We also distinguish that the metastable transition atH4is the first order and crucial for the ferrimagnetic to ferromagnetic transition. This study is useful to the understanding of multistep magnetization in α-CoV2O6and sheds light on recent experimental findings of related compounds.

7.
Eur Rev Med Pharmacol Sci ; 24(17): 8628, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32964947

RESUMO

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "LncRNA PROX1-AS1 promotes proliferation, invasion, and migration in prostate cancer via targeting miR-647, by C. Qian, C.-H. Liao, B.-F. Tan, Y.-F. Chen, B.-W. Dang, J.-L. Chen, C.-B. Liu, published in Eur Rev Med Pharmacol Sci 2020; 24 (6): 2938-2944-DOI: 10.26355/eurrev_202003_20658-PMID: 32271411" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/20658.

8.
Eur Rev Med Pharmacol Sci ; 24(6): 2938-2944, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32271411

RESUMO

OBJECTIVE: Long noncoding RNAs (lncRNAs) act as an important role in many diseases. In this research, lncRNA PROX1-AS1 was explored to identify how it functioned in the development of prostate cancer (PC). PATIENTS AND METHODS: Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was utilized to detect PROX1-AS1 expression in PC patients. Then, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, colony formation assay, and transwell assay were performed to identify its function in PC cells. Furthermore, the potential mechanism was also explored using mechanism assays. RESULTS: PROX1-AS1 expression level was significantly higher in PC tissue samples and cell lines. Results of MTT assay, colony formation assay, and transwell assay showed that cell proliferation and invasion were inhibited through the silence of PROX1-AS1 in PC cells, while cell proliferation and invasion were promoted through the overexpression of PROX1-AS1 in PC cells. Furthermore, the expression of miR-647 was upregulated via the silence of PROX1-AS1 in PC cells, while the expression of miR-647 was downregulated via the overexpression of PROX1-AS1 in PC cells. Further mechanism assays showed that miR-647 was a direct target of PROX1-AS1 in PC. Correlation analysis showed that miR-647 expression was negatively correlated with PROX1-AS1 expression in PC tissues. CONCLUSIONS: Results above suggested that PROX1-AS1 could enhance cell proliferation and invasion of PC cells by sponging miR-647 and might be applied as a novel target for the treatment of PC.

9.
J Phys Condens Matter ; 31(37): 375802, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31163414

RESUMO

The Ising-like antiferromagnet α-CoV2O6 has received considerable interests because of stabilized 1/3 magnetization plateau around 5 K under magnetic field applied along magnetic easy c-axis. In this work, this magnetization plateau was studied by varying temperature or rotating magnetic field. As temperature decreased, this stabilized plateau collapsed, and additional magnetic transitions were observed. As a result, a rich magnetic phase diagram was constructed and extended to temperature lower than previously reported. When magnetic field moved from the c to b (or a) axis, the magnetization plateau developed with field directions and vanished finally when the field was restricted in the ab plane. An impressive observation is that this 1/3-plateau can be stabilized and remain robust even when magnetic field deviated from the c axis, accompanied by the evolutions of the magnetic moments and the critical transition fields. We suppose that the origins of these temperature and angular dependences of the 1/3 magnetization plateau are related to strong spin-orbital coupling. Indeed, electron spin resonance (ESR) measurement gives large Landé factor of 8.9, evidencing that there exists strong spin-orbital coupling.

10.
Artigo em Chinês | MEDLINE | ID: mdl-31914279

RESUMO

Summary Inflammatory myofibroblastic tumor(IMT) is a rare spindle neoplasm with malignant potentials of local invasion, recurrence and metastasis. Here, we present an extremely unusual case of the larynx IMT that was recurred three times and transformed into laryngeal squamous cell carcinoma.


Assuntos
Granuloma de Células Plasmáticas , Neoplasias Laríngeas , Laringe , Neoplasias de Tecido Muscular , Humanos , Recidiva Local de Neoplasia
11.
Artigo em Chinês | MEDLINE | ID: mdl-30282175

RESUMO

Summary Cervical pharyngeal syndrome is characterized by the symptom such as sore throat, foreign body sensation or swallowing discomfort which caused by the pathological changes of cervical intervertebral disc and intervertebral structure nonspecific injury. Because of the lack of obvious specificity, it is easy to misdiagnose. Here, we reported a case of cervical pharyngeal syndrome. The symptom were obviously improved after conservative treatment, but the follow-up time is short, and further follow-up is needed. In the process of diagnosis and treatment, in order to reduce misdiagnosis and mistreatment, we should strengthen the understanding of the disease, broaden the clinical thinking, and understand the anatomical relationship between the pharynx and the surrounding organs.

13.
Zhonghua Zhong Liu Za Zhi ; 39(12): 919-925, 2017 Dec 23.
Artigo em Chinês | MEDLINE | ID: mdl-29262509

RESUMO

Objective: To investigate the safety and efficacy of the Weitan Waifu patch on the postsurgical gastroparesis syndrome (PGS) of gastrointestinal cancer. Methods: The multi-center, double-blind, randomized controlled trial was conducted with superiority design. Patients with PGS of gastrointestinal cancer diagnosed in 4 AAA hospitals and the abdominal symptom manifested as cold syndrome by Chinese local syndrome differentiation were recruited. These patients were randomly divided into two groups according to 1∶1 proportion. Placebo or Weitan Waifu patch was applied in control group or intervention group, respectively, based on the basic treatments, including nutrition support, gastrointestinal decompression, promoting gastric dynamics medicine.Two acupuncture points (Zhongwan and Shenque) were stuck with placebo in control group or patch in treatment group. The intervention course was 14 days or reached the effective standard. Results: From July 15, 2013 to Jun 3, 2015, 128 participants were recruited and 120 eligible cases were included in the full analysis set (FAS), and 60 cases in each group. 88 cases were included in the per-protocol set (PPS), including 45 cases in the treatment group and 43 cases in the control group. In the FAS, the clinical effective rate in the treatment group was 68.3%, significantly superior than 41.7% of the control group (P=0.003). The medium time of effective therapy in the treatment group was 8 days, significantly shorter than 10 days in the control group (P=0.017). In the FAS, 3 adverse events occurred in the treatment group, including mild to moderate decrustation, pruritus and nausea. The incidence rate of adverse events was 5.0% (3/60) and these symptoms were spontaneously remitted after drug withdrawal. No severe adverse events were observed in the control group. There was no significant difference between these two groups (P=0.244). Conclusion: Weitan Waifu patch is a safely and effectively therapeutic method for patients with PGS (cold syndrome) of gastroenterological cancer. Trial registration: International Standard Randomized Controlled Trial Number Register, ISRCTN18291857.


Assuntos
Medicamentos de Ervas Chinesas/uso terapêutico , Neoplasias Gastrointestinais/cirurgia , Gastroparesia/tratamento farmacológico , Complicações Pós-Operatórias/tratamento farmacológico , Adesivo Transdérmico , Pontos de Acupuntura , Método Duplo-Cego , Humanos , Síndrome , Adesivo Transdérmico/efeitos adversos , Resultado do Tratamento
14.
Genet Mol Res ; 16(1)2017 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-28362978

RESUMO

Association of signal-induced proliferation-associated 1 (SIPA) gene and protein expression with gastric cancer development was examined. SIPA1 mRNA and protein levels were determined by real-time quantitative polymerase chain reaction and western blot, respectively, in 40 gastric tumor and tumor-adjacent normal tissues. SIPA1, VEGF-A, and FVIII levels in 60 gastric tumor and 40 tumor-adjacent normal tissues were examined by immunohistochemical staining. Correlations between SIPA1, VEGF-A, and microvessel density (MVD) were analyzed. SIPA1 mRNA levels were significantly lower in tumor tissues than in tumor-adjacent normal tissues (P < 0.05). Similarly, protein levels were significantly lower in tumor tissues (0.3043 ± 0.1062) than in tumor-adjacent normal tissues (0.5423 ± 0.0682, P < 0.05). Positive staining rates of SIPA1 (48.3%) and VEGF-A (36.7%) were lower and higher, respectively, in tumor tissues than in tumor-adjacent normal tissues (65.0 and 2.5%, P < 0.05). Positive protein staining rates in tumor tissues correlated with the degree of differentiation, lymph node metastases, and clinical grading (P < 0.05) and not with sex, age, or tumor size (P > 0.05). Significantly higher MVD (57.4 ± 9.3) was observed in tumor tissues displaying positive SIPA1 staining than in tumor-adjacent normal tissues (41.2 ± 5.7, P < 0.05). SIPA1 and VEGF-A expression in tumor tissues were negatively correlated (r = -0.736, P < 0.05). SIPA1 and its protein may play important roles in gastric cancer invasion, metastasis, and biological behavior. Low SIPA1 levels in gastric cancer may accelerate tumor development and progression by promoting VEGF-A expression to increase vascular density.


Assuntos
Regulação para Baixo , Proteínas Ativadoras de GTPase/genética , Proteínas Ativadoras de GTPase/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Neoplasias Gástricas/patologia , Adulto , Idoso , Fator VIII/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
Genet Mol Res ; 14(4): 16133-45, 2015 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-26662405

RESUMO

It has been shown that microRNA-215 (miR-215) is dysregulated in several human malignancies, and this correlates with tumor progression. However, its expression and function in pancreatic cancer is still unclear. The aim of this study was to explore the effects of miR-215 on pancreatic cancer formation and progression. Using quantitative RT-PCR, we detected miR-215 expression in pancreatic cancer cell lines and primary tumor tissues. The association of miR-215 expression with clinicopathological factors and prognosis was also analyzed. We then observed the effects of miR-215 on the biological behavior of pancreatic cancer cells. Lastly, the potential regulatory function of miR-215 on ZEB2 expression was investigated. miR-215 expression levels were significantly downregulated in pancreatic cancer samples and cell lines. Decreased miR-215 expression was significantly associated with large tumor size, advanced TNM stage, lymph node metastasis, vessel invasion, and lower overall survival. Multivariate regression analysis corroborated that downregulation of miR-215 was an independent unfavorable prognostic factor. Overexpression of miR-215 inhibited pancreatic cancer cell proliferation, invasion, and migration; promoted cell apoptosis in vitro; and suppressed tumorigenicity in vivo. Further, ZEB2 was confirmed as a direct target of miR-215 by using a luciferase reporter assay. These findings indicate that miR-215 may act as a tumor suppressor in pancreatic cancer cells, and could serve as a novel therapeutic target for miR-based therapy.


Assuntos
Genes Supressores de Tumor , Proteínas de Homeodomínio/genética , MicroRNAs/genética , Neoplasias Pancreáticas/genética , Interferência de RNA , Proteínas Repressoras/genética , Regiões 3' não Traduzidas , Adulto , Idoso , Animais , Apoptose/genética , Sequência de Bases , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Regulação para Baixo , Feminino , Regulação Neoplásica da Expressão Gênica , Xenoenxertos , Proteínas de Homeodomínio/química , Humanos , Masculino , Camundongos , MicroRNAs/química , Pessoa de Meia-Idade , Gradação de Tumores , Metástase Neoplásica , Estadiamento de Neoplasias , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Prognóstico , RNA Mensageiro/química , RNA Mensageiro/genética , Proteínas Repressoras/química , Carga Tumoral , Homeobox 2 de Ligação a E-box com Dedos de Zinco
16.
Chem Commun (Camb) ; 48(64): 7964-6, 2012 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-22763758

RESUMO

Mixed zinc-lanthanide (Zn-Ln) metal-organic frameworks (MOFs) based on the 3,5-pyrazoledicarboxylate ligand exhibit an unusual three-dimensional (3D) inorganic subnetwork and display highly efficient photoluminescence.


Assuntos
Ácidos Carboxílicos/química , Elementos da Série dos Lantanídeos/química , Compostos Organometálicos/química , Pirazóis/química , Zinco/química , Ligantes , Luminescência , Modelos Moleculares , Compostos Organometálicos/síntese química
17.
Biochim Biophys Acta ; 1824(4): 533-41, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22326747

RESUMO

Epinephrine is a naturally occurring adrenomedullary hormone that transduces environmental stressors into cardiovascular actions. As the only route in the catecholamine biosynthetic pathway, Phenylethanolamine N-methyltransferase (PNMT) catalyzes the synthesis of epinephrine. To elucidate the detailed mechanism of enzymatic catalysis of PNMT, combined quantum-mechanical/molecular-mechanical (QM/MM) calculations were performed. The calculation results reveal that this catalysis contains three elementary steps: the deprotonation of protonated norepinphrine, the methyl transferring step and deprotonation of the methylated norepinphrine. The methyl transferring step was proved to be the rate-determining step undergoing a SN2 mechanism with an energy barrier of 16.4kcal/mol. During the whole catalysis, two glutamic acids Glu185 and Glu219 were proved to be loaded with different effects according to the calculations results of the mutants. These calculation results can be used to explain the experimental observations and make a good complementarity for the previous QM study.


Assuntos
Simulação por Computador , Modelos Químicos , Feniletanolamina N-Metiltransferase/química , Biocatálise , Domínio Catalítico , Ácido Glutâmico/química , Humanos , Cinética , Metilação , Modelos Moleculares , Nordefrin/química , Oxirredução , Teoria Quântica , Termodinâmica
18.
Biochim Biophys Acta ; 1824(2): 263-8, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21925621

RESUMO

Limonene 1,2-epoxide hydrolase (LEH) is completely different from those of classic epoxide hydrolases (EHs) which catalyze the hydrolysis of epoxides to vicinal diols. A novel concerted general acid catalysis step involving the Asp101-Arg99-Asp132 triad is proposed to play an important role in the mechanism. Combined quantum-mechanical/molecular-mechanical (QM/MM) calculations gave activation barriers of 16.9 and 25.1kcal/mol at the B3LYP/6-31G(d,p)//CHARMM level for nucleophilic attack on the more and less substituted epoxide carbons, respectively. Furthermore, the important roles of residues Arg99, Tyr53 and Asn55 on mutated LEH were evaluated by QM/MM-scanned energy mapping. These results may provide an explanation for site-directed mutagenesis.


Assuntos
Proteínas de Bactérias/química , Epóxido Hidrolases/química , Modelos Moleculares , Rhodococcus/enzimologia , Termodinâmica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biocatálise , Domínio Catalítico , Simulação por Computador , Cristalografia por Raios X , Monoterpenos Cicloexânicos , Epóxido Hidrolases/genética , Epóxido Hidrolases/metabolismo , Hidrólise , Monoterpenos/química , Monoterpenos/metabolismo , Mutagênese Sítio-Dirigida , Estrutura Terciária de Proteína , Teoria Quântica , Estereoisomerismo , Relação Estrutura-Atividade
19.
SAR QSAR Environ Res ; 22(7-8): 775-99, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22004567

RESUMO

Receptor-based comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on a series of 54 progesterone receptor (PR) inhibitors. The established CoMFA model from the training set gives statistically significant results with the cross-validated q (2) of 0.534 and non-cross-validated [Formula: see text] of 0.947. The best CoMSIA model was derived by the combination of steric field and hydrophobic field with a q (2) of 0.615 and [Formula: see text] of 0.954. A test set of 18 compounds was used to validate the predictive ability of the two models. The predicted correlation coefficients [Formula: see text] are 0.681 and 0.677 for CoMFA and CoMSIA models, respectively. Based on the CoMFA maps, the key structural characters of progesterone receptor inhibitors are identified. Moreover, the binding modes of oxindoles and benzimidazol-2-ones are also given by the quantum mechanical/molecular mechanical (QM/MM) calculations. This may provide useful information for drug design.


Assuntos
Benzimidazóis/química , Benzimidazóis/metabolismo , Indóis/química , Indóis/metabolismo , Relação Quantitativa Estrutura-Atividade , Receptores de Progesterona/antagonistas & inibidores , Concentração Inibidora 50 , Modelos Teóricos , Estrutura Molecular , Oxindóis
20.
J Int Med Res ; 39(3): 712-28, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21819702

RESUMO

This retrospective study investigated gene expression in tumour samples from 38 patients with early stage human papillomavirus (HPV)-associated cervical squamous cell carcinoma (CSCC). The patients were divided into two groups based on the presence of viral markers of HPV16 or HPV18 infection. Gene expression profiles of tumour samples and the corresponding normal cervical epithelium were analysed using cDNA microarrays. Several genes showed differential expression between the two groups of HPV-infected CSCC patients, although seven genes showed similar changes in both groups. The four genes encoding cyclin-dependent kinase inhibitor 2A, matrix metallopeptidase 9, laminin γ-1, and epidermal growth factor receptor were up-regulated, and the three genes encoding transforming growth factor ß receptor 1, interleukin-1α and insulin-like growth factor-binding protein 6 were down-regulated, in both HPV16(+) and HPV18(+) CSCC. These proteins are involved in cell proliferation, cell structure and cell attachment, so their expression might be involved in the mechanism of HPV-induced carcino genesis. A clearer understanding of HPV type-specific gene expression might aid diagnosis and treatment.


Assuntos
Alphapapillomavirus/genética , Carcinoma de Células Escamosas/virologia , Genes Virais , Neoplasias do Colo do Útero/virologia , Adulto , Idoso , Sequência de Bases , Inibidor p16 de Quinase Dependente de Ciclina/genética , Primers do DNA , Receptores ErbB/genética , Feminino , Humanos , Proteína 6 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Interleucina-1alfa/genética , Laminina/genética , Metaloproteinase 9 da Matriz/genética , Pessoa de Meia-Idade , Hibridização de Ácido Nucleico , Receptores de Fatores de Crescimento Transformadores beta/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...