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1.
Phys Rev Lett ; 126(13): 136401, 2021 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-33861118

RESUMEN

Samarium hexaboride is a candidate for the topological Kondo insulator state, in which Kondo coherence is predicted to give rise to an insulating gap spanned by topological surface states. Here we investigate the surface and bulk electronic properties of magnetically alloyed Sm_{1-x}M_{x}B_{6} (M=Ce, Eu), using angle-resolved photoemission spectroscopy and complementary characterization techniques. Remarkably, topologically nontrivial bulk and surface band structures are found to persist in highly modified samples with up to 30% Sm substitution and with an antiferromagnetic ground state in the case of Eu doping. The results are interpreted in terms of a hierarchy of energy scales, in which surface state emergence is linked to the formation of a direct Kondo gap, while low-temperature transport trends depend on the indirect gap.

2.
Zhonghua Yi Xue Za Zhi ; 100(33): 2628-2632, 2020 Sep 08.
Artículo en Zh | MEDLINE | ID: mdl-32892611

RESUMEN

Objective: To evaluate the stress status of femoral head and neck, screws and acetabulum caused by femoral neck shortening after internal fixation of femoral neck fracture with finite element method, and to analyze the stress of proximal femoral neck and acetabulum from the mechanical point of view. Methods: CT scan data of hip of a healthy adult female were collected. Three-dimensional reconstruction MICs and related module function simulation was used to establish the postoperative shortening model of femoral neck fracture with Pauwells angle>50°, which was treated with cannulated screws. The models were divided into four groups: normal femoral neck without shortening, shortening for 2.5 mm, shortening for 7.5 mm and shortening for 12.5 mm. The finite element analysis software MSC. Nastran2012 was used to do the mechanical analysis. The acetabulum surface, femoral head surface, proximal femur and the maximum stress, stress nephogram and other relevant data were collected. Results: The maximum tensile stress and the maximum stress at the fracture site of the femoral neck increased gradually with the increasing of shortening of femoral neck, however, the maximum compressive stress under the femoral neck and the medial cortex decreased gradually; the maximum stress on the surface of the femoral head was 14.9, 15.0, 16.3 and 16.3 MPa, respectively; the maximum stress on the surface of the acetabulum was 10.1, 10.1 and 10.5,11.7 MPa, respectively. Conclusion: The mechanical environment of the hip joint changes with femoral neck shortening. With the increasing of femoral neck shortening, the peak stress of the acetabulum increases continuously. When the femoral neck is shortened seriously, the load distribution is uneven and the complex mobility of hip joint is decreased. In addition, the change of shortening might play a role in the necrosis of femoral head.


Asunto(s)
Fracturas del Cuello Femoral , Adulto , Tornillos Óseos , Femenino , Cuello Femoral , Análisis de Elementos Finitos , Fijación Interna de Fracturas , Articulación de la Cadera , Humanos
3.
Vox Sang ; 2018 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-30003551

RESUMEN

BACKGROUND AND OBJECTIVES: Despite safety measures to minimize the risk of transfusion-transmitted infections, a residual risk remains. To trace and review some such cases, we ask donors to notify the blood centre if they are diagnosed with an infection after they donate blood. MATERIALS AND METHODS: We analysed all data on postdonation cases of hepatitis A reported between 2007 and 2012. Archived specimens from these donors were tested for hepatitis A virus (HAV) using anti-HAV IgM/IgG and HAV-PCR as markers. If any of the test results were positive, we reviewed the medical records of the recipients and, if necessary, tested them for hepatitis A. RESULTS: Fifteen blood donors notified the blood centres of having been diagnosed with hepatitis A after donation. All archived samples except for one were HAV-PCR-positive and anti-HAV IgM/IgG-negative. Of the donated components, four RBCs and 14 FFPs had not been transfused to patients and were recalled. Among 26 recipients of the implicated components, fourteen were still alive when they were notified. Two patients showed clinical symptoms of hepatitis A and had positive results with anti-HAV IgM. CONCLUSION: Transfusion-transmitted hepatitis A is rare but exists. To reduce the risk, donors should be told to notify the blood centre if they are diagnosed with blood-borne diseases after they donate blood. Physicians should consider the possibility of transfusion-transmitted hepatitis A if a transfused patient has hepatitis A but no history of travel or route of faecal-oral infection.

4.
Appl Opt ; 56(9): 2529-2534, 2017 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-28375363

RESUMEN

We investigate temperature-dependent carrier dynamics of InAs crystal by using reflection-type terahertz time-domain spectroscopy, particularly with a recently developed emitter-sample hybrid structure. We successfully obtain the optical conductivity in a terahertz frequency of bulk InAs whose dc conductivity is in the range of 100-150 Ω-1 cm-1. We find that both real and imaginary parts of the optical conductivity can be fit well with the simple Drude model, and the free-carrier density and the scattering rate obtained from the fit are in good agreement with corresponding values obtained by using other techniques, such as the Hall measurement and the dc-resistivity measurement. These results clearly demonstrate that the proposed technique of adopting the emitter-sample hybrid structure can be exploited to determine temperature-dependent optical constants in a reflection geometry and hence to investigate electrodynamics of bulk metallic systems.

5.
Zhonghua Yi Xue Za Zhi ; 96(31): 2487-92, 2016 Aug 16.
Artículo en Zh | MEDLINE | ID: mdl-27562048

RESUMEN

OBJECTIVE: To investigate the characterizations of genetic recombination hotspots and linkage disequilibrium (LD) patterns in peroxisome proliferative activated receptor gamma (PPARG) gene in Kirgiz and Uyghur ethnic groups. METHODS: Blood samples were collected from 100 Kirgiz (50 healthy controls and 50 patients with type 2 diabetes mellitus) residents in Halajun County, Artux City, Kizilsu Kirgiz Autonomous Prefecture, Xinjiang in August 2013, and 50 healthy Uyghur residents in Hotan Prefecture of Xinjiang Uygur Autonomous Region in May 2012.Thirty-one tagSNPs in PPARG gene were genotyped using Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) method.The recombination hotspots and LD patterns within the PPARG gene were estimated by analyzing the SNP genotying data using the Hotspot Fisher program and Haploview software, respectively. RESULTS: Eighteen tagSNPs (rs1151999, rs1175540, rs1875796, rs1899951, rs2292101, rs2921190, rs2938397, rs2959272, rs2959273, rs2972162, rs3856806, rs4135247, rs4135275, rs709151, rs4135354, rs6805419, rs17036700 and rs4135304) were same with relatively higher recombination rates between the patients with type 2 diabetes mellitus (T2DM) and healthy controls of Kirgiz ethnic group, and healthy controls of Uyghur ethnic group.Five haplotype blocks with LD coefficient D' value of 1, indicating no genetic recombination occurred within the region, were observed in the healthy controls of Kirgiz ethnic groups, whereas five haplotype blocks with LD coefficient D' value less than 1 were observed in the Kirgiz patients with T2DM, indicating historical recombination events occurred within the region.Four haplotype blocks with LD coefficient D' value of 1 were observed in the Uyghur healthy controls, indicating no genetic recombination occurred within the region.There were significantly different recombination hotspot profiles between the Kirgiz, Uyghur, Utah residents with Northern and Western European ancestry (CEU), Yoruban in Ibadan, Nigeria (YRI) and Han Chinese in Beijing (CHB) and Japanese in Tokyo (JPT) samples.There are six recombination hotspots in the HapMap profile of genetic recombination.The last 5 SNPs within the PPARG gene were shown with lower recombination rates in the Kirgiz, whereas no recombination hotspot was found in the Uyghur. CONCLUSIONS: Variable recombination rates may be present in certain chromosome region between patients and healthy controls within the same or between the different ethnic groups.There may be presence of recombination hotspots of ethnic specificity and with variable recombination rates.


Asunto(s)
Recombinación Genética , Pueblo Asiatico , Diabetes Mellitus Tipo 2 , Genotipo , Haplotipos , Humanos , Desequilibrio de Ligamiento , PPAR gamma , Polimorfismo de Nucleótido Simple
6.
Rev Sci Instrum ; 94(8)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38065176

RESUMEN

Although restricted by a limited range of strain, the triaxial compression test is a mature and common technique for investigating the rheological properties of rock materials at high pressures and high temperatures, especially when establishing the constitutive equations for various flow laws. The Paterson gas-medium high-pressure and high-temperature mechanical testing apparatus (Paterson apparatus) is the best apparatus for triaxial compression testing due to its high stress resolution. However, to derive accurate mechanical information from the raw data recorded by the Paterson apparatus, some technical issues should be addressed, including the simultaneous distortion of the apparatus, the load force supported by the jacketing tube, and the change in the cross-sectional area of the specimen. In this paper, we introduce correction methods corresponding to these three technical issues for triaxial compression on a Paterson apparatus equipped with an internal load cell to significantly reduce experimental errors so that high-precision mechanical data for establishing the constitutive equations of flow laws, such as differential stress, strain, and strain rate, can be obtained. To facilitate corrections for the distortion of the apparatus and the load force supported by the jacketing tube, we determine the distortion of the Paterson apparatus as a function of axial load force by deforming tungsten steel specimens with a known Young's modulus and the high-temperature flow laws of two common jacketing materials, iron and copper, by triaxial compression experiments at confining pressures of 200-300 MPa. Previous flow laws of iron and copper established by Frost and Ashby (1982) using ambient mechanical data are carefully compared with the flow laws obtained in this study to evaluate their effectiveness for correcting jacket tube strength. Finally, the errors eliminated by each correction step are analyzed and discussed to better understand the necessity of mechanical data corrections.

7.
J Phys Condens Matter ; 34(34)2022 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-35667370

RESUMEN

We report the temperature dependence of the Yb valence in the geometrically frustrated compoundYbB4from 12 to 300 K using resonant x-ray emission spectroscopy at the YbLα1transition. We find that the Yb valence,v, is hybridized between thev = 2 andv = 3 valence states, increasing fromv=2.61±0.01at 12 K tov=2.67±0.01at 300 K, confirming thatYbB4is a Kondo system in the intermediate valence regime. This result indicates that the Kondo interaction inYbB4is substantial, and is likely to be the reason whyYbB4does not order magnetically at low temperature, rather than this being an effect of geometric frustration. Furthermore, the zero-point valence of the system is extracted from our data and compared with other Kondo lattice systems. The zero-point valence seems to be weakly dependent on the Kondo temperature scale, but not on the valence change temperature scaleTv.

8.
Sci Rep ; 11(1): 737, 2021 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-33436945

RESUMEN

This paper discusses the use of nanomaterials for the improved performance of time-of-flight particle detectors based on secondary electron emission (SEE). The purpose of the research presented in this paper is to find a nanomaterial that has a higher SEE than gold. In this article, we present a measurement of the SEE properties from 1D (one-dimensional) nanostructures of ZnO and ZnO/GaN (ZnO with GaN coating) composed of a mostly regular pattern of nanotubes grown on a thin Si3N4 substrate. The study was performed with 4.77 meV/u Au beam. We observed an average increase of 2.5 in the SEE properties from the 1D ZnO nanotubes compared to gold.

9.
Sci Rep ; 10(1): 803, 2020 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-31964946

RESUMEN

The interplay of charge, spin, orbital and lattice degrees of freedom has recently received great interest due to its potential to improve the magnetocaloric effect (MCE) for the purpose of magnetic cooling applications. Here, a new mechanism for a large entropy change with low magnetic fields in rare-earth tetraborides, especially for Ho1-xDyxB4 (x = 0.0, 0.5, and 1.0), is proposed. For x = 0.0, 0.5, and 1.0, the maximum entropy changes of the giant inverse MCE are found to be 22.7 J/kgK, 19.6 J/kgK, and 19.0 J/kgK with critical fields of 25 kOe, 40 kOe, and 50 kOe, respectively. For all compounds, systematic study on how the entropy changes as a function of the field and temperature is performed to investigate their correlation with consecutive double transitions, i.e., the magnetic dipolar order at T = TN and the quadrupolar order at T = TQ (TQ < TN). Based on Landau theory, it is found that this behaviour is attributed to the strong coupling between magnetic dipoles and quadrupoles in the presence of strong spin-orbit coupling and geometric frustration. Our work offers new insights into both academic and industrial interests in the discovery of giant MCE with various applications for magnetic cooling systems.

10.
Ultrasound Obstet Gynecol ; 33(5): 552-9, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19350566

RESUMEN

OBJECTIVES: The clinical outcome of prenatally diagnosed congenital heart defects (CHD) continues to be affected significantly by associated extracardiac and chromosomal abnormalities. We sought to: determine the frequency and type of major extracardiac abnormalities (with impact on quality of life) and chromosomal abnormalities associated with fetal CHD; and compare the extracardiac abnormalities detected prenatally to the postnatal and autopsy findings in affected fetuses, to find the incidence of extracardiac abnormalities missed on prenatal ultrasound. METHODS: We reviewed the computerized database of the Division of Cardiology of the Hospital for Sick Children in Toronto to identify all cases of major CHD detected prenatally from 1990 to 2002. Medical records, fetal echocardiograms and ultrasound, cytogenetic and autopsy reports were reviewed. The types of CHD detected were grouped into categories and the frequencies of major extracardiac and chromosomal abnormalities in these categories were noted. Prenatal ultrasound findings were compared with those at autopsy or postnatal examination. RESULTS: Of 491 fetuses with major structural CHD, complete data were obtained for 382. Of these, there were 141 (36.9%) with major extracardiac abnormalities at autopsy or postnatal exam, of which 46 had chromosomal abnormalities and 95 did not. In the absence of chromosomal abnormalities, the organ systems most affected were urogenital (12.2%) and gastrointestinal (11.6%). CHDs with the highest incidence of extracardiac abnormalities (>25%) included: heterotaxy, single left ventricle and tricuspid atresia, hypoplastic left heart syndrome and tetralogy of Fallot. Ninety-four of 334 (28.1%) fetuses tested had chromosomal abnormalities. The most common chromosomal abnormalities were trisomies 21 (43.6%), 18 (19.1%) and 13 (9.6%), monosomy X (7.4%) and 22q11.2 deletion (7.4%). Of 289 extracardiac abnormalities from the complete series, 134 (46.4%) were not identified prenatally. Of the missed extracardiac abnormalities, 65 were considered not detectable at prenatal ultrasound, so 23.9% (69/289) of detectable extracardiac abnormalities were missed prenatally. CONCLUSIONS: Major extracardiac and chromosomal abnormalities are common in fetuses with major fetal CHD. Many important associated extracardiac abnormalities may be missed prenatally, which should be taken into consideration in the prenatal counseling for fetal CHD.


Asunto(s)
Anomalías Múltiples/diagnóstico , Aberraciones Cromosómicas/embriología , Corazón Fetal , Cardiopatías Congénitas/diagnóstico , Cardiopatías Congénitas/genética , Anomalías Múltiples/genética , Anomalías Múltiples/patología , Autopsia , Femenino , Corazón Fetal/diagnóstico por imagen , Corazón Fetal/patología , Asesoramiento Genético , Edad Gestacional , Cardiopatías Congénitas/patología , Humanos , Incidencia , Embarazo , Resultado del Embarazo , Diagnóstico Prenatal/normas , Estudios Retrospectivos , Ultrasonografía Prenatal
11.
Eur J Neurosci ; 28(10): 1989-2002, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19046381

RESUMEN

It has been suggested that accumulation of beta-amyloid (Abeta) peptide triggers neurodegeneration, at least in part, via glutamate-mediated excitotoxicity in Alzheimer's disease (AD) brain. This is supported by observations that toxicity induced by Abeta peptide in cultured neurons and in adult rat brain is known to be mediated by activation of glutamatergic N-methyl-d-aspartate (NMDA) receptors. Additionally, recent clinical studies have shown that memantine, a noncompetitive NMDA receptor antagonist, can significantly improve cognitive functions in some AD patients. However, very little is currently known about the potential role of memantine against Abeta-induced toxicity. In the present study, we have shown that Abeta(1-42)-induced toxicity in rat primary cortical cultured neurons is accompanied by increased extracellular and decreased intracellular glutamate levels. We subsequently demonstrated that Abeta toxicity is induced by increased phosphorylation of tau protein and activation of tau kinases, i.e. glycogen synthase kinase-3beta and extracellular signal-related kinase 1/2. Additionally, Abeta treatment induced cleavage of caspase-3 and decreased phosphorylation of cyclic AMP response element binding protein, which are critical in determining survival of neurons. Memantine treatment significantly protected cultured neurons against Abeta-induced toxicity by attenuating tau-phosphorylation and its associated signaling mechanisms. However, this drug did not alter either conformation or internalization of Abeta(1-42) and it was unable to attenuate Abeta-induced potentiation of extracellular glutamate levels. These results, taken together, provide new insights into the possible neuroprotective action of memantine in AD pathology.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/antagonistas & inhibidores , Memantina/farmacología , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Proteínas tau/efectos de los fármacos , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/fisiopatología , Péptidos beta-Amiloides/toxicidad , Animales , Caspasa 3/efectos de los fármacos , Caspasa 3/metabolismo , Células Cultivadas , Corteza Cerebral/metabolismo , Corteza Cerebral/fisiopatología , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/efectos de los fármacos , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Activación Enzimática/efectos de los fármacos , Activación Enzimática/fisiología , Antagonistas de Aminoácidos Excitadores/farmacología , Líquido Extracelular/efectos de los fármacos , Líquido Extracelular/metabolismo , Ácido Glutámico/metabolismo , Neuronas/metabolismo , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/toxicidad , Fosforilación/efectos de los fármacos , Fosfotransferasas/efectos de los fármacos , Fosfotransferasas/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/fisiología , Proteínas tau/metabolismo
12.
Neuropharmacology ; 54(4): 721-33, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18222494

RESUMEN

The invariant characteristic features associated with Alzheimer's disease (AD) brain include the presence of extracellular neuritic plaques composed of amyloid beta (Abeta) peptide, intracellular neurofibrillary tangles containing hyper-phosphorylated tau protein and the loss of basal forebrain cholinergic neurons. Studies of the pathological changes that characterize AD and several other lines of evidence indicate that in vivo accumulation of Abeta(1-42) may initiate the process of neurodegeneration observed in AD brains. However, the cause of degeneration of the basal forebrain cholinergic neurons and their association to Abeta peptides or phosphorylated tau protein have not been clearly established. In the present study, using rat primary septal cultures, we have shown that Abeta(1-42), in a time (1-48 h) and concentration (0.01-20 microM)-dependent manner, induce toxicity in cultured neurons. Subsequently, we have demonstrated that Abeta toxicity is mediated via activation of cysteine proteases, i.e., calpain and caspase, and proteolytic breakdown of their downstream substrates tau, microtubule-associated protein-2 and alpha II-spectrin. Additionally, Abeta-treatment was found to induce phosphorylation of tau protein along with decreased levels of phospho-Akt and phospho-Ser(9)glycogen synthase kinase-3beta. Exposure to specific inhibitors of caspase or calpain can partially protect cultured neurons against Abeta-induced toxicity but their effects are not found to be additive. These results, taken together, suggest that Abeta peptide can induce toxicity in rat septal cultured neurons by activating multiple intracellular signaling molecules. Additionally, evidence that inhibitors of caspase and calpains can partially protect the cultured basal forebrain neurons raised the possibility that their inhibitors could be of therapeutic relevance in the treatment of AD pathology.


Asunto(s)
Péptidos beta-Amiloides/toxicidad , Calpaína/metabolismo , Caspasas/metabolismo , Muerte Celular/efectos de los fármacos , Neuronas/efectos de los fármacos , Fragmentos de Péptidos/toxicidad , Tabique del Cerebro/citología , Animales , Proteínas de Unión al Calcio/farmacología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Embrión de Mamíferos , Inhibidores Enzimáticos/farmacología , Femenino , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Microscopía Electrónica de Rastreo/métodos , Proteínas Asociadas a Microtúbulos/metabolismo , Ovillos Neurofibrilares/ultraestructura , Neuronas/ultraestructura , Oligopéptidos/farmacología , Embarazo , Ratas , Sales de Tetrazolio , Tiazoles , Factores de Tiempo
13.
Int J Immunogenet ; 35(1): 69-74, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18186801

RESUMEN

Severe acute respiratory syndrome (SARS), caused by infection with a novel coronavirus (SARS-CoV), was the first major novel infectious disease at the beginning of the 21st century, with China especially affected. SARS was characterized by high infectivity, morbidity and mortality, and the confined pattern of the disease spreading among the countries of South-East and East Asia suggested the existence of susceptible factor(s) in these populations. Studies in the populations of Hong Kong and Taiwan showed an association of human leucocyte antigen (HLA) polymorphisms with the development and/or severity of SARS, respectively. The aim of the present study was to define the genotypic patterns of HLA-A, -B and -DRB1 loci in SARS patients and a co-resident population of Guangdong province, southern China, where the first SARS case was reported. The samples comprised 95 cases of recovered SARS patients and 403 unrelated healthy controls. HLA -A, -B and -DRB1 alleles were genotyped using polymerase chain reaction with sequence-specific primers. The severity of the disease was assessed according to the history of lung infiltration, usage of assisted ventilation and occurrence of lymphocytopenia. Although the allelic frequencies of A23, A34, B60, DRB1*12 in the SARS group were slightly higher, and A33, -B58 and -B61 were lower than in the controls, no statistical significance was found when the Pc value was considered. Similarly, no association of HLA alleles with the severity of the disease was detected. Thus, variations in the major histocompatibility complex are unlikely to have contributed significantly to either the susceptibility or the severity of SARS in the population of Guangdong.


Asunto(s)
Antígenos HLA-A/genética , Antígenos HLA-B/genética , Antígenos HLA-DR/genética , Síndrome Respiratorio Agudo Grave/genética , Adulto , Estudios de Casos y Controles , China , Estudios de Cohortes , Femenino , Antígenos HLA-A/inmunología , Antígenos HLA-B/inmunología , Antígenos HLA-DR/inmunología , Cadenas HLA-DRB1 , Humanos , Masculino , Persona de Mediana Edad , Síndrome Respiratorio Agudo Grave/inmunología
14.
J Hum Hypertens ; 32(8-9): 555-563, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29867134

RESUMEN

Hypertension results from the interaction of genetic and acquired factors. IgG occurs in the form of different subclasses, of which the effector functions show significant variation. The detailed differences between the glycosylation profiles of the individual IgG subclasses may be lost in a profiling method for total IgG N-glycosylation. In this study, subclass-specific IgG Fc glycosylation profile was investigated in the four northwestern Chinese minority populations, namely, Uygur (UIG), Kazak (KZK), Kirgiz (KGZ), and Tajik (TJK), composed of 274 hypertensive patients and 356 healthy controls. The results showed that ten directly measured IgG N-glycan traits (i.e., IgG1G0F, IgG2G0F, IgG2G1FN, IgG2G1FS, IgG2G2S, IgG4G0F, IgG4G1FS, IgG4G1S, IgG4G2FS, and IgG4G2N) representing galactosylation and sialylation are significantly associated with hypertension, with IgG4 consistently showing weaker associations of its sialylation, across the four ethnic groups. We observed a modest improvement on the AUC of ROC curve when the IgG Fc N-glycan traits are added into the glycan-based model (difference between AUCs, 0.044, 95% CI: 0.016-0.072, P = 0.002). The AUC of the diagnostic model indicated that the subclass-specific IgG Fc N-glycan profiles provide more information reinforcing current models utilizing age, gender, BMI, and ethnicity, and demonstrate the potential of subclass-specific IgG Fc N-glycosylation profiles to serve as a biomarker for hypertension. Further research is however required to determine the additive value of subclass-specific IgG Fc N-glycosylation on top of biomarkers, which are currently used.


Asunto(s)
Hipertensión/inmunología , Inmunoglobulina G/metabolismo , Adulto , Anciano , Asia Central/etnología , Biomarcadores/sangre , Estudios de Casos y Controles , China/epidemiología , Femenino , Glicosilación , Humanos , Hipertensión/etnología , Masculino , Persona de Mediana Edad
15.
Mol Cell Biol ; 16(10): 5328-34, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8816444

RESUMEN

The binding of mRNA to the ribosome is mediated by eukaryotic initiation factors eukaryotic initiation factor 4F (eIF4F), eIF4B, eIF4A, and eIF3, eIF4F binds to the mRNA cap structure and, in combination with eIF4B, is believed to unwind the secondary structure in the 5' untranslated region to facilitate ribosome binding. eIF3 associates with the 40S ribosomal subunit prior to mRNA binding. eIF4B copurifies with eIF3 and eIF4F through several purification steps, suggesting the involvement of a multisubunit complex during translation initiation. To understand the mechanism by which eIF4B promotes 40S ribosome binding to the mRNA, we studied its interactions with partner proteins by using a filter overlay (protein-protein [far Western]) assay and the two-hybrid system. In this report, we show that eIF4B self-associates and also interacts directly with the p170 subunit of eIF3. A region rich in aspartic acid, arginine, tyrosine, and glycine, termed the DRYG domain, is sufficient for self-association of eIF4B, both in vitro and in vivo, and for interaction with the p170 subunit of eIF3. These experiments suggest that eIF4B participates in mRNA-ribosome binding by acting as an intermediary between the mRNA and eIF3, via a direct interaction with the p170 subunit of eIF3.


Asunto(s)
Factores Eucarióticos de Iniciación , Factores de Iniciación de Péptidos/química , Factores de Iniciación de Péptidos/metabolismo , Animales , Arginina , Ácido Aspártico , Secuencia de Bases , Sitios de Unión , Clonación Molecular , Cartilla de ADN , Proteínas de Unión al ADN/metabolismo , Factor 3 de Iniciación Eucariótica , Glicina , Humanos , Sustancias Macromoleculares , Modelos Estructurales , Reacción en Cadena de la Polimerasa , ARN Mensajero/metabolismo , Conejos , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Reticulocitos/metabolismo , Ribosomas/metabolismo , Saccharomyces cerevisiae , Tirosina
16.
J Int Med Res ; 35(3): 301-6, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17593857

RESUMEN

Alzheimer's disease (AD) is characterized by the deposition of senile plaques and neurofibrillary tangles in the brain. The presence of the amyloid-beta (Abeta) peptide in senile plaques seems to play a central role in the neuropathology of AD. Diagnosis of AD involves neuropsychological examinations or magnetic resonance imaging and, to date, a specific diagnostic marker indicating AD has not been found. This study analysed anti-Abeta antibodies from the serum of 153 patients with AD using an enzyme-linked immunosorbent assay method. The levels of anti-Abeta antibody from patients in the control group (n=193) were compared with those of patients with AD. Our results showed a significantly lower anti-Abeta antibody level in patients with AD than in the control group. These results showed that the anti-Abeta antibody level in serum could potentially be used to diagnose the presence of AD.


Asunto(s)
Enfermedad de Alzheimer/inmunología , Péptidos beta-Amiloides/inmunología , Anticuerpos/sangre , Anciano , Enfermedad de Alzheimer/diagnóstico , Estudios de Casos y Controles , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Corea (Geográfico) , Modelos Logísticos , Masculino , Valor Predictivo de las Pruebas , Distribución Aleatoria
17.
Cancer Res ; 61(22): 8322-30, 2001 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-11719466

RESUMEN

The M(r) 78,000 glucose-regulated protein (GRP78) can be induced by physiological stresses such as glucose deprivation and hypoxia. In solid tumors, hypoxia can promote malignant progression and confer resistance to irradiation and chemotherapy by altering gene expression. Here, we investigated the molecular mechanisms and signaling pathway involved in the late and prolonged induction of the GRP78 gene by hypoxia in a human gastric cancer cell line, MKN28. Nuclear run-on assays and mRNA stability measurements revealed that transcriptional activation, not stabilization of mRNA, contributed to the dramatic induction of GRP78 gene under hypoxia. Induction of GRP78 by chronic hypoxia was completely abolished by pretreatment with PD98059 [a specific inhibitor of mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK1)] or by overexpression of a dominant-negative MEK1 mutant, demonstrating a direct involvement of ERK in the induction of transcription at the GRP78 promoter under these conditions. Furthermore, hypoxia increased the transcriptional activity of a 12-O-tetradecanoylphorbol-13-acetate response element-like motif on the GRP78 promoter and increased the abundance and DNA binding activity of AP-1 complex composed of c-Jun and c-Fos. A selective protein kinase C (PKC) inhibitor, GF109203X, inhibited the induction of GRP78 gene expression as well as the activities of both ERK and Raf-1. Among six PKC isoforms expressed in MKN28 cells, PKC-epsilon expression level and kinase activity were increased by hypoxia. Transfection of MKN28 cells with a dominant-negative PKC-epsilon blocked the induction of GRP78 through ERK by hypoxia, indicating that PKC-epsilon directly participated in GRP78 induction under hypoxia. Taken together, this study shows that a PKC-epsilon-Raf-1-MEK-ERK-AP1 signaling cascade acts on a 12-O-tetradecanoylphorbol-13-acetate response element-like element to mediate hypoxia-induced GRP78 expression in human gastric cancer cells. We also confirmed in vivo the overexpression of GRP78 in surgical specimens of human primary gastric tumors.


Asunto(s)
Adenocarcinoma/metabolismo , Proteínas Portadoras/biosíntesis , Proteínas de Choque Térmico , Isoenzimas/fisiología , Sistema de Señalización de MAP Quinasas/fisiología , Quinasas de Proteína Quinasa Activadas por Mitógenos/fisiología , Chaperonas Moleculares/biosíntesis , Proteína Quinasa C/fisiología , Neoplasias Gástricas/metabolismo , Adenocarcinoma/genética , Proteínas Portadoras/genética , Hipoxia de la Célula/fisiología , Chaperón BiP del Retículo Endoplásmico , Activación Enzimática , Regulación Neoplásica de la Expresión Génica/fisiología , Humanos , Isoenzimas/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Chaperonas Moleculares/genética , Regiones Promotoras Genéticas/fisiología , Proteína Quinasa C/metabolismo , Proteína Quinasa C-epsilon , Proteínas Proto-Oncogénicas c-raf/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Neoplasias Gástricas/genética , Factor de Transcripción AP-1/fisiología , Activación Transcripcional
18.
Neuroscience ; 307: 37-50, 2015 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-26297896

RESUMEN

Alzheimer's disease (AD), the most common type of dementia, is characterized by the presence of senile plaques, neurofibrillary tangles, and neuronal loss in defined regions of the brain including the hippocampus and cortex. Transplantation of bone marrow-derived mesenchymal stem cells (BM-MSCs) offers a safe and potentially effective tool for treating neurodegenerative disorders. However, the therapeutic effects of BM-MSCs on AD pathology remain unclear and their mechanisms at cellular and molecular levels still need to be addressed. In this study, we developed a unique neuronal culture made from 5xFAD mouse, an APP/PS1 transgenic mouse model (FAD neurons) to investigate progressive neurodegeneration associated with AD pathology and efficacy of brain-derived neurotrophic factor expressing-MSCs (BDNF-MSCs). Analyses of the expression of brain-derived neurotrophic factor (BDNF), synaptic markers and survival/apoptotic signals indicate that pathological features of cultured neurons made from these mice accurately mimic AD pathology, suggesting that our protocol provided a valid in vitro model of AD. We also demonstrated amelioration of AD pathology by MSCs in vitro when these FAD neurons were co-cultured with MSCs, a paradigm that mimics the in vivo environment of post-transplantation of MSCs into damaged regions of brains. To overcome failed delivery of BDNF to the brain and to enhance MSCs releasing BDNF effect, we created BDNF-MSCs and found that MSCs protection was enhanced by BDNF-MSCs. This protection was abolished by BDNF-blocking peptides, suggesting that BDNF supply from BDNF-MSCs was enough to prevent AD pathology.


Asunto(s)
Enfermedad de Alzheimer/complicaciones , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Células Madre Mesenquimatosas/fisiología , Enfermedades Neurodegenerativas/etiología , Enfermedades Neurodegenerativas/patología , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Precursor de Proteína beta-Amiloide/genética , Animales , Apoptosis/genética , Encéfalo/citología , Encéfalo/metabolismo , Encéfalo/patología , Factor Neurotrófico Derivado del Encéfalo/genética , Caspasa 3/metabolismo , Células Cultivadas , Técnicas de Cocultivo , Modelos Animales de Enfermedad , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutación/genética , Proteínas del Tejido Nervioso/metabolismo , Neuronas/metabolismo , Presenilina-1/genética
19.
Br J Pharmacol ; 135(4): 943-50, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11861322

RESUMEN

1. Orphanin FQ (OFQ), an endogenous peptide for ORL1 receptors, has been identified. Although the actions of OFQ have much in common with those of opioid peptides at the cellular level, behavioral studies in rodents seem conflicting. 2. The aim of this study was to investigate the potential pronociceptive or antinociceptive function of peripheral ORL1 receptors in primates. Experiments were conducted to verify whether local administration of OFQ can attenuate capsaicin-induced nociception and whether peripheral ORL1 receptors selectively mediate the local action of OFQ in monkeys. 3. Capsaicin (100 microg) was administered subcutaneously in the tail to locally evoke a nociceptive response (thermal allodynia/hyperalgesia), which was manifested as a reduced tail-withdrawal latency in normally innocuous 46 degreeC warm water. 4. Co-administration of OFQ (1--30 microg) with capsaicin in the tail dose-dependently inhibited thermal nociception. However, a locally effective dose of OFQ (30 microg), when applied in the back, did not inhibit capsaicin-induced nociception. 5. OFQ-induced local antinociception was antagonized by a small dose (10 microg) of J-113397, a selective ORL1 receptor antagonist, in the tail. Similarly, s.c. administration of 10 microg of J-113397 in the back did not antagonize local antinociception of OFQ. 6. In addition, s.c. administration of either OFQ or J-113397 in the tail alone did not change its thermal nociceptive threshold. Local administration of opioid receptor antagonists selective for mu, kappa, and delta opioid receptors did not antagonize OFQ-induced local antinociception. Local administration of J-113397 also did not interfere with the local actions of mu, kappa, and delta opioid agonists in the tail. 7. These results provide the first functional evidence that activation of peripheral ORL1 receptors produces thermal antinociception in primates and this action is independent of antinociception produced at classical opioid receptors.


Asunto(s)
Capsaicina , Péptidos Opioides , Dolor/metabolismo , Receptores Opioides/agonistas , Animales , Bencimidazoles/farmacología , Femenino , Calefacción , Macaca mulatta , Masculino , Péptidos Opioides/farmacología , Dolor/etiología , Piperidinas/farmacología , Cola (estructura animal) , Receptor de Nociceptina , Nociceptina
20.
Arch Dermatol ; 133(1): 57-61, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9006373

RESUMEN

OBJECTIVE: To identify the structures in hair follicles (HFs) targeted by alopecia areata (AA) antibodies and the role of antigen expression in the development or localization of AA lesions. DESIGN: The identity of HF structures targeted by AA antibodies was determined by indirect immunofluorescence and the level of antigen expression from the intensity of the staining. SETTING: A university medical center. PATIENTS: Ten patients with active AA and 8 control individuals. RESULTS: Antibodies to anagen HFs were present in up to 90% of patients with AA but in less than 37% of controls. The antibodies in patients with AA reacted to antigens present only in HFs. The structures most commonly targeted were the outer root sheath and, less often, the inner root sheath, matrix, and hair shaft. The same HF structure contained several immunologically distinct antigens reactive with AA antibodies. The expression of some AA antigens was much greater in the scalp of patients with AA than in normal individuals. CONCLUSIONS: These findings indicate that the autoantibody responses to HFs in patients with AA are heterogeneous and target multiple structures in anagen HFs. The expression of some as-yet-unidentified HF antigens is increased in many patients with AA, suggesting that the initiation, localization, severity, and persistence of the disease may be related to the level of expression of some HF antigens.


Asunto(s)
Alopecia Areata/inmunología , Autoanticuerpos/inmunología , Folículo Piloso/inmunología , Adulto , Alopecia Areata/sangre , Autoanticuerpos/análisis , Autoanticuerpos/biosíntesis , Autoantígenos/análisis , Autoantígenos/biosíntesis , Femenino , Humanos , Masculino , Persona de Mediana Edad
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