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1.
Zhonghua Xin Xue Guan Bing Za Zhi ; 51(7): 731-741, 2023 Jul 24.
Artigo em Chinês | MEDLINE | ID: mdl-37460427

RESUMO

Objective: For patients with atrial fibrillation (AF) complicated with acute coronary syndrome (ACS), both anticoagulant and antiplatelet therapy should be applied, but the use of anticoagulation therapy is still poor in these patients in China. The purpose of this study was to explore the status and adherence of antithrombotic therapy in AF patients with ACS and the impact on 1 year clinical outcomes. Methods: Patients with AF hospitalized for ACS were retrospectively included from 6 tertiary hospitals in China between July 2015 and December 2020. According to the use of anticoagulant drugs at discharge, patients were divided into two groups: anticoagulant treatment group and non-anticoagulant treatment group. Logistic regression model was used to analyze the main factors influencing the use of anticoagulant drugs in patients with atrial fibrillation complicated with ACS. Major adverse cardiac events (MACEs) were defined as all-cause death, non-fatal myocardial infarction or coronary revascularization, and ischemic stroke and Bleeding Academic Research Consortium (BARC) 3 bleeding events were also collected at 1 year after discharge. After propensity score matching, Cox proportional hazards models and Kaplan-Meier analysis were used to evaluate the effect of anticoagulant treatment and non-anticoagulant treatment on 1-year prognosis. The patients were divided into different groups according to whether anticoagulation was performed at discharge and follow-up, and the sensitivity of the results was analyzed. Results: A total of 664 patients were enrolled, and 273 (41.1%) were treated with anticoagulant therapy, of whom 84 (30.8%) received triple antithrombotic therapy, 91 (33.3%) received double antithrombotic therapy (single antiplatelet combined with anticoagulant), and 98 (35.9%) received single anticoagulant therapy. Three hundred and ninety-one (58.9%) patients were treated with antiplatelet therapy, including 253 (64.7%) with dual antiplatelet therapy and 138 (35.3%) with single antiplatelet therapy. After 1∶1 propensity score matching between the anticoagulant group and the non-anticoagulant group, a total of 218 pairs were matched. Multivariate logistic regression analysis showed that history of diabetes, HAS-BLED score≥3, and percutaneous coronary intervention were predictors of the absence of anticoagulant therapy, while history of ischemic stroke and persistent atrial fibrillation were predictors of anticoagulant therapy. At 1-year follow-up, 218 patients (79.9%) in the anticoagulant group continued to receive anticoagulant therapy, and 333 patients (85.2%) in the antiplatelet group continued to receive antiplatelet therapy. At 1-year follow-up, 36 MACEs events (13.2%) occurred in the anticoagulant group, and 81 MACEs events (20.7%) in the non-anticoagulant group. HR values and confidence intervals were calculated by Cox proportional risk model. Patients in the non-anticoagulant group faced a higher risk of MACEs (HR=1.802, 95%CI 1.112-2.921, P=0.017), and the risk of bleeding events was similar between the two group (HR=0.825,95%CI 0.397-1.715, P=0.607). Conclusions: History of diabetes, HAS-BLED score≥3, and percutaneous coronary intervention are independent factors for the absence of anticoagulant therapy in patients with AF complicated with ACS. The incidence of MACEs, death and myocardial infarction is lower in the anticoagulant group, and the incidence of bleeding events is similar between the two groups. The risk of bleeding and ischemia/thrombosis should be dynamically assessed during follow-up and antithrombotic regiments should be adjusted accordingly.


Assuntos
Síndrome Coronariana Aguda , Fibrilação Atrial , AVC Isquêmico , Infarto do Miocárdio , Intervenção Coronária Percutânea , Acidente Vascular Cerebral , Humanos , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Inibidores da Agregação Plaquetária/uso terapêutico , Inibidores da Agregação Plaquetária/efeitos adversos , Síndrome Coronariana Aguda/complicações , Síndrome Coronariana Aguda/tratamento farmacológico , Fibrinolíticos/uso terapêutico , Estudos Retrospectivos , Resultado do Tratamento , Anticoagulantes , Infarto do Miocárdio/complicações , Hemorragia , AVC Isquêmico/complicações , AVC Isquêmico/tratamento farmacológico
2.
Zhonghua Er Ke Za Zhi ; 60(5): 435-441, 2022 May 02.
Artigo em Chinês | MEDLINE | ID: mdl-35488637

RESUMO

Objective: To explore the heterogeneity and correlation of clinical phenotypes and genotypes in children with disorders of sex development (DSD). Methods: A retrospective study of 1 235 patients with clinically proposed DSD in 36 pediatric medical institutions across the country from January 2017 to May 2021. After capturing 277 DSD-related candidate genes, second-generation sequencing was performed to analyzed the heterogeneity and correlation combined with clinical phenotypes. Results: Among 1 235 children with clinically proposed DSD, 980 were males and 255 were females of social gender at the time of initial diagnosis with the age ranged from 1 day of age to 17.92 years. A total of 443 children with pathogenic variants were detected through molecular genetic studies, with a positive detection rate of 35.9%. The most common clinical phenotypes were micropenis (455 cases), hypospadias (321 cases), and cryptorchidism (172 cases) and common mutations detected were in SRD5A2 gene (80 cases), AR gene (53 cases) and CYP21A2 gene (44 cases). Among them, the SRD5A2 mutation is the most common in children with simple micropenis and simple hypospadias, while the AMH mutation is the most common in children with simple cryptorchidism. Conclusions: The SRD5A2 mutation is the most common genetic variant in Chinese children with DSD, and micropenis, cryptorchidism, and hypospadias are the most common clinical phenotypes. Molecular diagnosis can provide clues about the biological basis of DSD, and can also guide clinicians to perform specific clinical examinations. Target sequence capture probes and next-generation sequencing technology can provide effective and economical genetic diagnosis for children with DSD.


Assuntos
Criptorquidismo , Transtornos do Desenvolvimento Sexual , Hipospadia , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/genética , Criança , China/epidemiologia , Criptorquidismo/genética , Transtornos do Desenvolvimento Sexual/diagnóstico , Transtornos do Desenvolvimento Sexual/genética , Feminino , Doenças dos Genitais Masculinos , Genótipo , Humanos , Hipospadia/genética , Masculino , Proteínas de Membrana/genética , Pênis/anormalidades , Fenótipo , Estudos Retrospectivos , Esteroide 21-Hidroxilase/genética
3.
Zhonghua Zhong Liu Za Zhi ; 43(7): 801-805, 2021 Jul 23.
Artigo em Chinês | MEDLINE | ID: mdl-34289576

RESUMO

Objective: To analyze the association between low-frequency variants of ARID1A gene and primary liver cancer using latent category model. Methods: The low-frequency variants of ARID1A gene was combined according to different functional areas, and the combined variables were analyzed by using the latent class model to obtain the latent variables. Then the logistic regression was used to analyze the association between low-frequency variants of ARID1A gene and primary liver cancer. Results: The low-frequency variants of ARID1A gene were divided into three categories by the latent class model. The class 1 was mainly unmutated population, the proportion was 94.2% (2 454/2 603). The class 2 was mainly transcriptional regulatory domain mutation, take 4.8% (124/2 603). The class 3 was dominantly exon mutation, about 1.0% (27/2 603). Using class 1 as a reference, it was found that mutations in the transcriptional regulatory domain could reduce the risk of liver cancer (OR=0.601, 95% CI=0.364-0.992, P=0.046). Conclusion: The latent class model can identify low-frequency variants of gene associated with liver cancer and can be extended to more genetic association studies of low-frequency variants related to complex diseases.


Assuntos
Neoplasias Hepáticas , Proteínas Nucleares , Proteínas de Ligação a DNA , Humanos , Análise de Classes Latentes , Neoplasias Hepáticas/genética , Mutação , Proteínas Nucleares/genética , Fatores de Transcrição/genética
4.
J Phys Condens Matter ; 33(39)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34252886

RESUMO

Two-dimensional (2D) materials attached with flexible substrates enable possibilities to apply their superior properties to the rapidly increasing demand for foldable displays and wearable biosensors in the internet-of-things technology. However, previous two-step strategy to construct the flexible devices, namely first obtaining 2D materials elsewhere and then transferring them onto flexible substrates, can cause huge problems, including irreversibly undermining the device performance and limiting the material size. Here we propose a new one-step strategy (other than the liquid phase processing and low temperature synthesis methods), namely directly depositing appropriate 2D materials onto flexible substrates, which involves no transferring and can maintain the crystal quality and properties to the greatest extent. More importantly, this strategy in principle has no limit in the film size, hence removing a main obstacle for the practical use of flexible films, such as complex logic operations and large-area optoelectronic applications. Using this strategy, a centimeter-scale SnSe2film is directly grown on polydimethylsiloxane, which is characterized as a uniform, out-of-plane oriented and semiconducting film that is robust to deformations. Based on the film, a flexible photodetector is fabricated and distinct photoresponse to a broad spectrum of light (405-830 nm) is observed, with remarkable technical parameters.

5.
Phys Rev Lett ; 123(19): 196602, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31765179

RESUMO

Thermoelectric effects are more sensitive and promising probes to topological properties of emergent materials, but much less addressed compared to other physical properties. We study the thermoelectric effects of ZrTe_{5} in a magnetic field. The presence of the nontrivial electrons leads to the anomalous Nernst effect and quasilinear field dependence of thermopower below the quantum limit. In the strong-field quantum limit, both the thermopower and Nernst signal exhibit exotic peaks. At higher magnetic fields, the Nernst signal has a sign reversal at a critical field where the thermopower approaches zero. We propose that these anomalous behaviors can be attributed to the gap closing of the zeroth Landau bands in topological materials with the band inversion. Our understanding to the anomalous thermoelectric properties in ZrTe_{5} opens a new avenue for exploring Dirac physics in topological materials.

6.
Leuk Res ; 86: 106222, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31522038

RESUMO

INTRODUCTION: Mouse double minute 2 protein (MDM2), a negative regulator of the p53 tumour suppressor gene, is frequently amplified in malignancies. MDM2 antagonists have shown efficacy in treating malignancies with MDM2 overexpression and can overcome chemoresistance in acute myeloid leukemia. We systematically evaluated the safety profile of MDM2 inhibitors in the treatment of solid organ and hematologic malignancies. MATERIALS AND METHODS: We searched Medline and EMBASE from January 1947 to November 2018 for prospective clinical studies, in English or French, investigating any MDM2 inhibitor in pediatric or adult cancers, and reporting dose and toxicity outcomes. Primary outcome was dose-limiting toxicity (DLT) and secondary outcome was death. RESULTS: The search yielded 493 non-duplicate citations. Eighteen studies of 10 inhibitors met inclusion criteria (total N = 1005 patients). Two-thirds of included studies did not define DLTs and the reporting of toxicities was highly variable. The most commonly reported DLTs were cytopenias, gastrointestinal toxicity, metabolic disturbances, fatigue and cardiovascular toxicity; there was one death attributed to treatment toxicity. CONCLUSION: MDM2 antagonists have been studied in a variety of malignancies with toxicities similar to other commonly used chemotherapy agents and may represent a safe adjuvant treatment for further study in in acute leukemia.


Assuntos
Antineoplásicos/efeitos adversos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/diagnóstico , Neoplasias Hematológicas/tratamento farmacológico , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/etiologia , Estudos de Avaliação como Assunto , Neoplasias Hematológicas/patologia , Humanos , Dose Máxima Tolerável , Prognóstico
7.
Phys Rev Lett ; 120(14): 147204, 2018 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-29694140

RESUMO

We report detailed dc and ac magnetic susceptibilities, specific heat, and thermal conductivity measurements on the frustrated magnet ZnCr_{2}Se_{4}. At low temperatures, with an increasing magnetic field, this spinel material goes through a series of spin state transitions from the helix spin state to the spiral spin state and then to the fully polarized state. Our results indicate a direct quantum phase transition from the spiral spin state to the fully polarized state. As the system approaches the quantum criticality, we find strong quantum fluctuations of the spins with behaviors such as an unconventional T^{2}-dependent specific heat and temperature-independent mean free path for the thermal transport. We complete the full phase diagram of ZnCr_{2}Se_{4} under the external magnetic field and propose the possibility of frustrated quantum criticality with extended densities of critical modes to account for the unusual low-energy excitations in the vicinity of the criticality. Our results reveal that ZnCr_{2}Se_{4} is a rare example of a 3D magnet exhibiting a field-driven quantum criticality with unconventional properties.

8.
J Phys Condens Matter ; 30(15): 155701, 2018 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-29480806

RESUMO

Dirac node arc semimetal state is a new topological quantum state which is proposed to exist in PtSn4 (Wu et al 2016 Dirac node arcs in PtSn4 Nat. Phys. 12 667-71). We present a systematic de Haas-van Alphen quantum oscillation study on this compound. Two intriguing oscillation branches, i.e. F 1 and F 2, are detected in the fast Fourier transformation spectra, both of which are characterized to possess tiny effective mass and ultrahigh quantum mobility. And the F 2 branch exhibits an angle-dependent nontrivial Berry phase. The features are consistent with the existence of the node arc semimetal state and shed new light on its complicated Fermi surfaces and topological nature.

9.
Phys Rev Lett ; 118(20): 206601, 2017 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-28581794

RESUMO

We study the effect of hydrostatic pressure on the magnetotransport properties of zirconium pentatelluride. The magnitude of resistivity anomaly gets enhanced with increasing pressure, but the transition temperature T^{*} is insensitive to it up to 2.5 GPa. In the case of H∥b, the quasilinear magnetoresistance decreases drastically from 3300% (9 T) at ambient pressure to 230% (9 T) at 2.5 GPa. Besides, the change of the quantum oscillation phase from topological nontrivial to trivial is revealed around 2 GPa. Both demonstrate that the pressure breaks the accidental Dirac node in ZrTe_{5}. For H∥c, in contrast, subtle changes can be seen in the magnetoresistance and quantum oscillations. In the presence of pressure, ZrTe_{5} evolves from a highly anisotropic to a nearly isotropic electronic system, which accompanies the disruption of the accidental Dirac semimetal state. It supports the assumption that ZrTe_{5} is a semi-3D Dirac system with linear dispersion along two directions and a quadratic one along the third.

10.
Artigo em Chinês | MEDLINE | ID: mdl-29771045

RESUMO

Objective:The aim of this study is to explore the effects of autophagy on the metastasis of the Squamous Cell Carcinoma of Head and Neck (SCCHN) via epithelial to mesenchymal transition (EMT) induced by TGF-ß1. Method:Establish the EMT model induced by TGF-ß1 in the SCCHN in time/concentration, and the expression of autophagy related protein microtubule associated protein 1 light chain3 (LC3) detected by western blot; Autophagy inhibitor chloroquine (CQ), depressing autophagy, the expression of E-cadherin, cytokeratin, Vimentin and LC3 were examined by Western blot. Wound healing and Transwell invasion assay indicate the effects to metastasis for SCCHN. Result:Autophagy was activated within TGF-ß1 induced EMT model in the SCCHN in time/concentration dependently. After autophagy was suppressed, the expression of E-cadherin and cytokeratin increased while vimentin and the capacity of metastasis was reduced compared with control group. Conclusion:TGF-ß1 induce EMT and Autophagy in the SCCHN. Autophagy could enhances metastasis in the SCCHN via EMT induced by TGF-ß1.


Assuntos
Autofagia , Biomarcadores Tumorais , Carcinoma de Células Escamosas/patologia , Neoplasias de Cabeça e Pescoço/patologia , Invasividade Neoplásica , Caderinas , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Humanos , Fator de Crescimento Transformador beta1
11.
J Phys Condens Matter ; 28(18): 18LT01, 2016 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-27049604

RESUMO

The bond-frustrated ZnCr2Se4 displays strong spin-lattice coupling characterized by large magnetostriction and negative thermal expansion. Here, we report on systematic investigations on the magnetization, heat capacity, thermal expansion and magnetostriction of single crystalline ZnCr2(Se1-x S x )4 (0 ⩽ x ⩽ 0.1) to study the evolution of its spin-lattice coupling with sulfur substitution. We show that with increasing sulfur content, the antiferromagnetic ordering is gradually replaced by a spin-glass state, the temperature region of the negative thermal expansion expands, and the magnetostriction is gradually suppressed. These phenomena are explained qualitatively by taking into account the enhancement of the antiferromagnetic interactions and bond disorder introduced by sulfur substitution.

12.
J Phys Condens Matter ; 25(3): 035702, 2013 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-23238220

RESUMO

We report on the investigation of Co and Cu substitution effects on superconductivity and magnetism in Fe(1+y)Te(0.6)Se(0.4) single crystals. The parent Fe(1.01)Te(0.59)Se(0.41) shows a nodeless bulk superconductivity as revealed in heat capacity measurement, which is gradually suppressed by either Co or Cu doping. It is found that the Co or Cu doping mainly serves as scatterers rather than charge carrier doping, which is in agreement with the DFT calculation (2010 Phys. Rev. Lett. 105 157004) reported by Wadati et al. In comparison with Cu doping, Co doping shows a stronger influence on magnetism while a less evident suppression effect on superconductivity. Upon substitution of Co for Fe, a Schottky heat capacity anomaly develops gradually at low temperatures, implying the existence of a paramagnetic moment in the Co-doped samples. In contrast, Cu doping may mainly serve as non-magnetic scatterers, where no Schottky anomaly is observed.


Assuntos
Cobalto/química , Cobre/química , Condutividade Elétrica , Compostos Ferrosos/química , Magnetismo , Compostos de Selênio/química , Telúrio/química , Cristalização , Modelos Químicos , Óxidos de Selênio
13.
Hamilton; McMaster Health Forum; 2013. 71 p.
Monografia em Inglês | PIE | ID: biblio-1007305

RESUMO

Ontario's Action Plan for Health Care called for "right care, right time, right place" (p. 10) and specifically for "moving procedures into the community" (p. 13).(1) To support the implementation of this commitment, the ministry of health has taken several steps. The ministry has supported one midwifery-led birth centre in Ontario (on Six Nations of the Grand River territory) and announced in March 2012 plans for two more. The ministry may also announce another type of community-based specialty clinic in the coming months.


Assuntos
Humanos , Centros Comunitários de Saúde , Serviços de Saúde Comunitária , Ontário , Canadá , Modelos Organizacionais
14.
Hamilton; McMaster Health Forum; 2013. 56 p.
Monografia em Inglês | PIE | ID: biblio-1007700

RESUMO

Over the past three decades, Canada has made substantial progress in reducing the national rate of avoidable mortality (deaths that could potentially have been avoided through disease prevention or healthcare services). In fact, the national avoidable mortality rate has decreased by half ­ from 373 per 100,000 in 1979 to 185 per 100,000 in 2008.(1) During this period, avoidable mortality attributed to preventable causes decreased by 47%, while avoidable mortality attributed to treatable causes decreased by 56%. Additionally, Canada is faring well from an international standpoint, ranking the third lowest amongst G7 nations in rates of avoidable mortality, after Japan and France.(1) However, despite the significant gains that Canada has made in reducing avoidable mortality rates, there still exist variations in the distribution of avoidable mortality across provinces and territories, and across different population groups.(1) Additional efforts are needed to reduce avoidable mortality rates both among the jurisdictions and groups being 'left behind', as well as overall.


Assuntos
Humanos , Sistemas de Saúde/organização & administração , Indicadores de Morbimortalidade , Canadá , Coleta de Dados
15.
J Phys Condens Matter ; 22(50): 505704, 2010 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-21406807

RESUMO

The magnetization and anisotropic electrical transport properties have been measured in high quality Cu(0.03)TaS(2) single crystals. A pronounced peak effect has been observed, indicating that high quality and homogeneity are vital to the peak effect. A kink has been observed in the magnetic field, H, dependence of the in-plane resistivity ρ(ab) for H is parallel to c, which corresponds to a transition from activated to diffusive behavior of the vortex liquid phase. In the diffusive regime of the vortex liquid phase, the in-plane resistivity ρ(ab) is proportional to H(0.3), which does not follow the Bardeen-Stephen law for free flux flow. Finally, a simplified vortex phase diagram of Cu(0.03)TaS(2) for H is parallel to c is given.

16.
An Pediatr (Barc) ; 61(5): 413-7, 2004 Nov.
Artigo em Espanhol | MEDLINE | ID: mdl-15530321

RESUMO

OBJECTIVE: To describe the characteristics of patients with tap-water scalds admitted to our hospital and review current knowledge on their prevention. PATIENTS AND METHODS: We performed a retrospective study of admissions for tap-water scalds. The medical records codified as water-tap scalds (MBDS; CIE-9-CM, 940.0-949.5, E.924.0, E.924.2) of patients admitted to our hospital for more than 24 hours from January 1 to December 31, 2003 were reviewed. The following variables were studied: age, sex, mechanism, extent and degree of burn, localization, length of hospital stay, treatment, requirement for skin grafting, mortality, and sequelae. RESULTS: Twenty-nine patients were treated in our hospital. Sixty-two percent were boys. Age ranged from 3 days to 9 years. Six patients (20.6 %) were aged less than 1 year, 19 (63 %) were aged between 1 and 3 years and four (13.8 %) were aged from 3 to 9 years. Body surface area was 10 % or less in 25 patients and more than 20 % in four. Five patients required skin autografting. In two patients, the scald was produced in the neonatal area of our hospital. The mean length of hospital stay was 12 days, ranging from 1 to 38 days. None of the patients died. One patient suffered severe sequelae. CONCLUSIONS: Because of the frequency and severity of the burns reported in this study, pediatricians should increase their efforts in educating families about this type of burn. In addition, effective legislation should be implemented in Spain.


Assuntos
Queimaduras/etiologia , Queimaduras/epidemiologia , Queimaduras/prevenção & controle , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos , Água
17.
An. pediatr. (2003, Ed. impr.) ; 61(5): 413-417, nov. 2004.
Artigo em Es | IBECS | ID: ibc-35554

RESUMO

Objetivo: Describir las características de los pacientes que han precisado hospitalización por quemaduras producidas por agua sanitaria y revisar el estado actual de su prevención. Pacientes y métodos: Estudio retrospectivo por revisión de historias clínicas codificadas como quemaduras por agua sanitaria (CMBD; CIE-9-CM, 940.0-949.5, E924.0, E.924.2) ingresados durante más de 24 h en nuestro hospital desde el 1 de enero de 1998 hasta el 31 de diciembre de 2003. Se estudiaron las siguientes variables: edad, sexo, mecanismo, extensión y grado de profundidad de la quemadura, duración del ingreso, casos que requirieron injerto cutáneo, mortalidad y secuelas. Resultados: Se ha evaluado a 29 pacientes. El 62 por ciento eran varones. El rango de edad fue desde los 3 días de vida a los 9 años de edad. Seis pacientes eran menores de un año (20,6 por ciento), 19 de 1 a 3 años (63 por ciento), y 4 mayores de 3 años (13,8 por ciento). En cuanto a la superficie corporal quemada, en 25 casos fue igual o inferior a 10 por ciento, y en cuatro fue superior al 20 por ciento. Cinco pacientes requirieron la realización de autoinjerto cutáneo. Dos quemaduras fueron intrahospitalarias, que correspondían a dos recién nacidos. La estancia media fue de 12 días, con un rango de 1 a 38 días. Se observaron secuelas graves en un paciente. No hubo mortalidad. Conclusiones: La incidencia y la gravedad de los pacientes descritos justifican incrementar las medidas preventivas por parte del pediatra, y consideramos que deberían existir medidas de tipo legislativo en España (AU)


Assuntos
Criança , Recém-Nascido , Masculino , Lactente , Humanos , Feminino , Pré-Escolar , Água , Estudos Retrospectivos , Queimaduras
18.
Mol Gen Genet ; 258(5): 449-56, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9669326

RESUMO

The rice disease resistance gene Xa21, which encodes a receptor-like kinase, is a member of a multigene family. Based on comparisons of genomic sequences of seven family members, seventeen transposon-like elements were identified in the 5' and 3' flanking regions and introns of these genes. Sequence characterization revealed that these elements are diverse, showing similarity to maize Ds, CACTA and miniature inverted repeat-like elements, as well as novel elements. Only two elements were located in presumed coding regions, indicating that integration of transposable elements at the Xa21 disease resistance locus occurred preferentially in noncoding regions.


Assuntos
Elementos de DNA Transponíveis/genética , Oryza/genética , Doenças das Plantas/genética , Proteínas de Plantas/genética , Proteínas Serina-Treonina Quinases/genética , Sequência de Aminoácidos , Sequência de Bases , Íntrons/genética , Dados de Sequência Molecular , Família Multigênica/genética , Sequências Repetitivas de Ácido Nucleico/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico
19.
Plant Cell ; 10(5): 765-79, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9596635

RESUMO

The rice Xa21 gene confers resistance to Xanthomonas oryzae pv oryzae in a race-specific manner. Analysis of the inheritance patterns and resistance spectra of transgenic plants carrying six Xa21 gene family members indicated that one member, designated Xa21D, displayed a resistance spectrum identical to that observed for Xa21 but conferred only partial resistance. Xa21D encodes a receptor-like protein carrying leucine-rich repeat (LRR) motifs in the presumed extracellular domain. The Xa21D transcript terminates shortly after the stop codon introduced by the retrotransposon Retrofit. Comparison of nucleotide substitutions in the LRR coding regions of Xa21 and Xa21D provided evidence of adaptive selection. Both functional and evolutionary evidence indicates that the Xa21D LRR domain controls race-specific pathogen recognition.


Assuntos
Evolução Biológica , Família Multigênica , Oryza/genética , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Serina-Treonina Quinases/genética , Xanthomonas/patogenicidade , Adaptação Fisiológica , Sequência de Aminoácidos , Dimerização , Suscetibilidade a Doenças , Evolução Molecular , Leucina , Dados de Sequência Molecular , Oryza/microbiologia , Oryza/fisiologia , Doenças das Plantas , Proteínas de Plantas/química , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase , Proteínas Serina-Treonina Quinases/química , Receptores de Superfície Celular/biossíntese , Receptores de Superfície Celular/genética , Retroelementos , Alinhamento de Sequência , Xanthomonas/genética
20.
Plant Cell ; 9(8): 1279-87, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9286106

RESUMO

The rice disease resistance gene Xa21, encoding a receptor-like kinase, is a member of a multigene family. Sequence analysis of seven family members revealed two distinct classes of genes. One member from each class encodes a receptor kinase-like open reading frame. The other five members encode truncated open reading frames of the predicted receptor kinase. A highly conserved 233-bp sequence (HC) was also identified among the seven family members. Recombination at the HC region between family members apparently resulted in the precise swapping of promoter regions. Large sequence duplications were generated by a presumed unequal crossover event in intergenic regions. Insertions of transposon-like sequences truncated two of the predicted open reading frames. A model for amplification and diversification of the Xa21 gene family is presented.


Assuntos
Evolução Molecular , Genes de Plantas , Família Multigênica , Oryza/genética , Proteínas de Plantas/genética , Proteínas Serina-Treonina Quinases/genética , Sequência de Aminoácidos , Composição de Bases , Sequência de Bases , Clonagem Molecular , Sequência Conservada , Elementos de DNA Transponíveis , DNA de Plantas/química , DNA de Plantas/genética , Modelos Genéticos , Dados de Sequência Molecular , Oryza/enzimologia , Recombinação Genética
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