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1.
Nat Mater ; 23(10): 1370-1378, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39026087

RESUMO

Iron-based 1111-type superconductors display high critical temperatures and relatively high critical current densities Jc. The typical approach to increasing Jc is to introduce defects to control dissipative vortex motion. However, when optimized, this approach is theoretically predicted to be limited to achieving a maximum Jc of only ∼30% of the depairing current density Jd, which depends on the coherence length and the penetration depth. Here we dramatically boost Jc in SmFeAsO1-xHx films using a thermodynamic approach aimed at increasing Jd and incorporating vortex pinning centres. Specifically, we reduce the penetration depth, coherence length and critical field anisotropy by increasing the carrier density through high electron doping using H substitution. Remarkably, the quadrupled Jd reaches 415 MA cm-2, a value comparable to cuprates. Finally, by introducing defects using proton irradiation, we obtain high Jc values in fields up to 25 T. We apply this method to other iron-based superconductors and achieve a similar enhancement of current densities.

2.
Nat Mater ; 22(5): 591-598, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37012436

RESUMO

Large spin-orbit torques (SOTs) generated by topological materials and heavy metals interfaced with ferromagnets are promising for next-generation magnetic memory and logic devices. SOTs generated from y spin originating from spin Hall and Edelstein effects can realize field-free magnetization switching only when the magnetization and spin are collinear. Here we circumvent the above limitation by utilizing unconventional spins generated in a MnPd3 thin film grown on an oxidized silicon substrate. We observe conventional SOT due to y spin, and out-of-plane and in-plane anti-damping-like torques originated from z spin and x spin, respectively, in MnPd3/CoFeB heterostructures. Notably, we have demonstrated complete field-free switching of perpendicular cobalt via out-of-plane anti-damping-like SOT. Density functional theory calculations show that the observed unconventional torques are due to the low symmetry of the (114)-oriented MnPd3 films. Altogether our results provide a path toward realization of a practical spin channel in ultrafast magnetic memory and logic devices.

3.
J Am Chem Soc ; 145(5): 3008-3015, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36710457

RESUMO

The diversity and complexity of covalent organic frameworks (COFs) can be largely increased by incorporating multiple types of monomers with different topologies or sizes. However, an increase in the number of monomer types significantly complicates the COF formation process. Accordingly, much remains unclear regarding the viability of monomer combinations for ternary or higher-arity COFs. Herein, we show that, through an extensive examination of 12 two-nodes-one-linker ([2 + 1]) combinations, monomer-set viability is determined primarily by the conformational strain originating from disordered monomer arrangements, rather than other factors such as the difference in COF formation kinetics between monomers. When monomers cannot accommodate the strain associated with the formation of a locally disordered, yet crystalline framework, the corresponding [2 + 1] condensation yields a mixture of different COFs or an amorphous polymer. We also demonstrate that a node-linker pair that does not form a binary COF can be integrated to generate a single-phase framework upon addition of a small amount of the third component. These results will clarify the factors behind the successful formation of multicomponent COFs and refine their design by enabling accurate differentiation between allowed and disallowed monomer combinations.

4.
Nano Lett ; 20(8): 5735-5740, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32574061

RESUMO

A variety of nickel oxide compounds have long been studied for their manifestation of various correlated electron phenomena. Recently, superconductivity was observed in nanoscale infinite layer nickelate thin films of Nd0.8Sr0.2NiO2, epitaxially stabilized on SrTiO3 substrates via topotactic reduction from the perovskite precursor phase. Here, we present the synthesis and properties of PrNiO2 thin films on SrTiO3. Upon doping in Pr0.8Sr0.2NiO2, we observe superconductivity with a transition temperature of 7-12 K and robust critical current density at 2 K of 334 kA/cm2. These findings indicate that superconductivity in the infinite layer nickelates is relatively insensitive to the details of the rare earth 4f configuration. Furthermore, they motivate the exploration of a broader family of compounds based on two-dimensional NiO2 planes, which will enable systematic investigation of the superconducting and normal state properties and their underlying mechanisms.

5.
J Phys Ther Sci ; 33(9): 641-645, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34539067

RESUMO

[Purpose] This study aimed to clarify the relationship between the distance measurements in the Star Excursion Balance Test and participants' posture and lower limb muscle strength. [Participants and Methods] Nine healthy male college students participated in this study. Star Excursion Balance Test distance was measured in both lower limbs by performing anterior, posterolateral, and posteromedial trials; measuring the maximum reach; and performing three-dimensional motion analysis to determine the posture at maximum reach. Isokinetic muscle strength for knee flexion/extension, hip flexion/extension, and hip adduction/abduction were measured using an isokinetic machine. [Results] The hip extension strength, reach side ankle dorsiflexion angles, stance side knee flexion, reach side knee flexion, and knee flexion strength were selected as significant explanatory variables in the anterior direction. For the posteromedial direction, hip adduction and hip extension strength, reach side hip flexion angle, and stance side hip flexion angle were selected. For the posterolateral direction, reach side knee flexion angle and stance side ankle dorsiflexion, knee flexion strength and reach side hip flexion angle were selected. [Conclusion] The related factors differed between the dominant and non-dominant legs even in the same reach direction.

6.
J Phys Ther Sci ; 32(6): 391-394, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32581431

RESUMO

[Purpose] We examined and clarified the relationship between the maximum squat depth and the range of motion of the ankle, knee, and hip joints, and the knee and hip muscle strength. [Participants and Methods] Nine healthy males participated in this study and performed a deep squat with the upper extremities raised; the movement was analyzed by two-dimensional motion analysis. We measured the ankle dorsiflexion, hip flexion, and knee flexion ranges of motion, as well as the knee extension and hip flexion muscle strengths and analyzed the relationship between the squatting motion, the range of motion, and the muscle strength of each joint. [Results] The right ankle dorsiflexion range of motion was a significant predictor of the ankle dorsiflexion angle on both sides. The right knee flexion range of motion was a significant predictor of the knee flexion angle, and the left knee flexion range of motion was a significant predictor of the trunk anterior tilt angle on both sides. The right ankle dorsiflexion range of motion was a significant predictor of the right hip flexion angle and vice versa. [Conclusion] This study reveals that movement on one side affects contralateral movement, which is important when evaluating the deep squat motion as a functional test.

7.
Appl Microbiol Biotechnol ; 101(18): 6879-6889, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28756590

RESUMO

Sulfate (SO42-) is an often-utilized and well-understood inorganic sulfur source in microorganism culture. Recently, another inorganic sulfur source, thiosulfate (S2O32-), was proposed to be more advantageous in microbial growth and biotechnological applications. Although its assimilation pathway is known to depend on O-acetyl-L-serine sulfhydrylase B (CysM in Escherichia coli), its metabolism has not been extensively investigated. Therefore, we aimed to explore another yet-unidentified CysM-independent thiosulfate assimilation pathway in E. coli. ΔcysM cells could accumulate essential L-cysteine from thiosulfate as the sole sulfur source and could grow, albeit slowly, demonstrating that a CysM-independent thiosulfate assimilation pathway is present in E. coli. This pathway is expected to consist of the initial part of the thiosulfate to sulfite (SO32-) conversion, and the latter part might be shared with the final part of the known sulfate assimilation pathway [sulfite → sulfide (S2-) â†’ L-cysteine]. This is because thiosulfate-grown ΔcysM cells could accumulate a level of sulfite and sulfide equivalent to that of wild-type cells. The catalysis of thiosulfate to sulfite is at least partly mediated by thiosulfate sulfurtransferase (GlpE), because its overexpression could enhance cellular thiosulfate sulfurtransferase activity in vitro and complement the slow-growth phenotype of thiosulfate-grown ΔcysM cells in vivo. GlpE is therefore concluded to function in the novel CysM-independent thiosulfate assimilation pathway by catalyzing thiosulfate to sulfite. We applied this insight to L-cysteine overproduction in E. coli and succeeded in enhancing it by GlpE overexpression in media containing glucose or glycerol as the main carbon source, by up to ~1.7-fold (1207 mg/l) or ~1.5-fold (1529 mg/l), respectively.


Assuntos
Vias Biossintéticas , Escherichia coli/metabolismo , Tiossulfato Sulfurtransferase/metabolismo , Tiossulfatos/metabolismo , Cisteína/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Fermentação , Engenharia Genética , Glucose/metabolismo , Glicerol/metabolismo , Serina/metabolismo , Sulfatos/metabolismo , Sulfetos/metabolismo , Sulfitos/metabolismo , Enxofre/metabolismo , Tiossulfato Sulfurtransferase/genética
8.
J Orthop ; 45: 43-47, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37841906

RESUMO

Purpose: This study examined the differences in the center of pressure movement in a one-leg standing position with bare feet, thin-soled shoes, and thick-soled shoes. Methods: In total, 21 male university students participated in this study. The task involved standing on one leg with the dominant foot for 30 s, and the center of pressure movement was measured using a grab coder (G-620; ANIMA, Tokyo, Japan). Three shoe-wearing states, including bare feet, thin-soled shoes, and thick-soled shoes, with the eyes closed and open in each condition. Statistical analysis was performed, with the significance level set as 5%. Results: In the multiple comparison results, the anteroposterior (AP) locus length, AP locus length per second, and maximum amplitude in the AP direction were significantly larger with thick-soled shoes than with bare feet in the closed eyes state. The locus length per unit area was significantly smaller with the thick-soled shoes than with the barefoot condition. Other items did not differ significantly between the shoe-wearing states. Conclusion: Thick-soled shoes caused a greater center of pressure movement in the AP direction in the static one-leg standing position than did the barefoot state. Our findings suggest that the condition with thick-soled shoes was more unstable in static environments.

9.
iScience ; 26(4): 106563, 2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-37123243

RESUMO

Bromodomain-containing protein 8 (BRD8) is a subunit of the NuA4/TIP60-histone acetyltransferase complex. Although BRD8 has been considered to act as a co-activator of the complex, its biological role remains to be elucidated. Here, we uncovered that BRD8 accumulates in colorectal cancer cells through the inhibition of ubiquitin-dependent protein degradation by the interaction with MRG domain binding protein. Transcriptome analysis coupled with genome-wide mapping of BRD8-binding sites disclosed that BRD8 transactivates a set of genes independently of TIP60, and that BRD8 regulates the expression of multiple subunits of the pre-replicative complex in concert with the activator protein-1. Depletion of BRD8 induced cell-cycle arrest at the G1 phase and suppressed cell proliferation. We have also shown that the bromodomain of BRD8 is indispensable for not only the interaction with histone H4 or transcriptional regulation but also its own protein stability. These findings highlight the importance of bromodomain as a therapeutic target.

10.
PLoS One ; 17(12): e0279409, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36574389

RESUMO

As chimeric antigen receptor (CAR)-T cell therapy has been recently applied in clinics, controlling the fate of blood cells is increasingly important for curing blood disorders. In this study, we aim to construct proliferation-inducing and differentiation-inducing CARs (piCAR and diCAR) with two different antigen specificities and express them simultaneously on the cell surface. Since the two antigens are non-cross-reactive and exclusively activate piCAR or diCAR, sequential induction from cell proliferation to differentiation could be controlled by switching the antigens added in the culture medium. To demonstrate this notion, a murine myeloid progenitor cell line 32Dcl3, which proliferates in an IL-3-dependent manner and differentiates into granulocytes when cultured in the presence of G-CSF, is chosen as a model. To mimic the cell fate control of 32Dcl3 cells, IL-3R-based piCAR and G-CSFR-based diCAR are rationally designed and co-expressed in 32Dcl3 cells to evaluate the proliferation- and differentiation-inducing functions. Consequently, the sequential induction from proliferation to differentiation with switching the cytokine from IL-3 to G-CSF is successfully replaced by switching the antigen from one to another in the CARs-co-expressing cells. Thus, piCAR and diCAR may become a platform technology for sequentially controlling proliferation and differentiation of various cell types that need to be produced in cell and gene therapies.


Assuntos
Receptores de Antígenos Quiméricos , Camundongos , Animais , Receptores de Antígenos Quiméricos/genética , Interleucina-3/metabolismo , Receptores de Citocinas , Diferenciação Celular , Proliferação de Células , Fator Estimulador de Colônias de Granulócitos/farmacologia , Células Progenitoras Mieloides/metabolismo
11.
Infect Immun ; 79(9): 3810-20, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21746858

RESUMO

Two glucosylating toxins named toxins A and B play a role in the pathogenesis of Clostridium Difficile infection. The interaction of the toxins with host cell factors proceeds to downstream stages of cytotoxic effects in cells, in which involvement of other C. difficile factors remains unknown. We utilized culture filtrate of C. difficile with a low dilution to characterize the influence of putative minor proteins on the organization of the actin cytoskeleton in cultured epithelial cells and found a previously uncharacterized F-actin aggregated structure, termed "actin aggregate," at the juxtanuclear region. We reasoned that formation of actin aggregate was due to an additional factor(s) in the culture filtrate rather than the glucosylating toxins, because treatment of purified toxins rarely caused actin aggregate in cells. We focused on a previously uncharacterized hypothetical protein harboring a KDEL-like sequence as a candidate. The product of the candidate gene was detected in culture filtrate of C. difficile ATCC 9689 and was renamed Srl. Purified glutathione S-transferase-tagged Srl triggered formation of actin aggregate in the cells in the presence of either toxin A or B and enhanced cytotoxicity of each of the two toxins, including decreases in both cell viability and transepithelial resistance of cultured epithelial monolayer, although the recombinant Srl alone did not show detectable cytotoxicity. Srl-neutralized culture filtrate partially inhibited morphological changes of the cells in parallel with decreased actin aggregate formation in the cells. Thus, Srl might contribute to the modulation of toxin sensitivity of intestinal epithelial cells by enhancing cytotoxicity of C. difficile toxins.


Assuntos
Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/toxicidade , Clostridioides difficile/patogenicidade , Enterotoxinas/toxicidade , Células Epiteliais/efeitos dos fármacos , Fatores de Virulência/toxicidade , Actinas/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Sequência de Bases , Células CACO-2 , Linhagem Celular , Clostridioides difficile/genética , Clostridioides difficile/metabolismo , Meios de Cultivo Condicionados , Enterotoxinas/metabolismo , Células Epiteliais/microbiologia , Glutationa Transferase/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Alinhamento de Sequência , Análise de Sequência de DNA , Fatores de Virulência/genética
12.
ACS Synth Biol ; 10(5): 990-999, 2021 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-33909409

RESUMO

Intervention in protein-protein interactions (PPIs) has tremendous effects in the molecular therapy of many diseases. To fulfill the requirements for targeting intracellular proteins, here we develop SOS-localization-based interaction screening (SOLIS), which elaborately mimics signaling via the Ras-mitogen-activated protein kinase pathway. SOLIS employs two chimeric proteins in which a membrane localization motif (CaaX) is fused at the C-terminus of a protein of interest and the catalytic domain of SOS is fused at the C-terminus of another protein of interest. Interaction between the two proteins of interest induces membrane localization of the SOS chimera and cell proliferation. Thus, the SOLIS system enables enrichment of superior binders based on cell proliferation in an intracellular PPI-dependent manner. This was verified by three major modalities against intracellular PPIs (small molecules, peptide aptamers, and intrabodies). The system worked over a broad range of affinities (KD = 0.32-140 nM). In a screening of a site-directed randomized library, novel intrabody clones were selected on the basis of the potency of cell proliferation. Three other PPI detection methods (NanoBiT, SPR, and pull-down assays) were employed to characterize the SOLIS system, and several intrabody clones were judged as false negatives in these assays. SOLIS signals would be less sensitive to the orientation/conformation of the chimeric proteins, and this feature emerges as the advantage of SOLIS as a mammalian cytosolic PPI detection system with few false negatives.


Assuntos
Espaço Intracelular/metabolismo , Células Precursoras de Linfócitos B/metabolismo , Mapas de Interação de Proteínas , Transdução de Sinais/genética , Proteínas Son Of Sevenless/metabolismo , Animais , Anticorpos/metabolismo , Antígenos/metabolismo , Aptâmeros de Peptídeos/metabolismo , Linhagem Celular , Membrana Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Interleucina-3/genética , Interleucina-3/metabolismo , Interleucina-3/farmacologia , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Terapia de Alvo Molecular/métodos , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução Genética , Transfecção , Proteínas ras/metabolismo
13.
J Electron Microsc (Tokyo) ; 59 Suppl 1: S101-5, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20558467

RESUMO

A Y(1-X)Sm(x)Ba(2)Cu(3)O(y) (YSmBCO) superconductive layer containing BaZrO(3) (BZO) particles was fabricated on a Hastelloy substrate with a CeO(2)/Gd(2)Zr(2)O(7) buffer layer by trifluoroacetates-metal organic deposition. The nanostructures of the layer were characterized by transmission electron microscopy and found to be comparatively dense and predominantly composed of c-axis oriented grains. Some BaCeO(3) regions formed at the interface between the YSmBCO and the CeO(2) layers. BZO particles and the (Y,Sm)(2)Cu(2)O(5) (225) phase were formed in the YSmBCO. The average sizes of the BZO and the 225 phase particles were 20 and 150 nm, respectively, with random orientation. The BZO particles were found to be homogeneously distributed within the YSmBCO layer, which should enhance its superconducting behavior in high magnetic fields.

14.
Anal Sci ; 36(10): 1243-1247, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32475895

RESUMO

For improving quality control in the fermented tea production process and advancing the corresponding food labeling with function claims, a rapid and robust hesperidin analysis method using LC-MS/MS with the sample dilution approach was developed by following internationally accepted criteria of the Association of Official Analytical Chemists (AOAC). The linear correlation coefficient (r2) of the regression line was 0.9997 in the concentration range of 0.025 - 2.5 mg/L. The matrix effect evaluated using regression line slope values was negligible. The recovery rate of 100.7% indicated improved trueness. The performance of the newly developed method in determining the hesperidin content of fermented tea samples did not significantly vary from that of a well-established, conventional method. The HorRat values of intra- and inter-laboratory reproducibility studies were both within the acceptable range, indicating sufficient accuracy of the newly developed method according to the AOAC criteria.


Assuntos
Citrus/química , Frutas/química , Hesperidina/análise , Folhas de Planta/química , Chá/química , Cromatografia Líquida , Citrus/metabolismo , Fermentação , Frutas/metabolismo , Hesperidina/metabolismo , Folhas de Planta/metabolismo , Espectrometria de Massas em Tandem , Chá/metabolismo
15.
Anesthesiology ; 110(5): 1127-32, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19352162

RESUMO

BACKGROUND: In this study, lidocaine concentrations in cerebrospinal fluid (CSF) at different interspaces were measured with or without preceding spinal anesthesia, 10 min after epidural injection of lidocaine, to investigate the effects of preceding meningeal puncture on CSF concentrations of epidurally administered local anesthetic. METHODS: Sixty patients scheduled to receive combined spinal-epidural anesthesia were randomly allocated to receive either spinal anesthesia first (group CSEA) or epidural lidocaine first (group Epi). Each group was divided into three subgroups in which the site of epidural cannulation and spinal tap were separated by one, three, or five interspaces (sets I, II, and III, respectively). CSF was collected from the L4-L5 interspace 10 min after 10 ml lidocaine, 1%, was administered epidurally. In group Epi, CSF was collected after epidural administration of lidocaine and before spinal anesthesia. In group CSEA, spinal anesthesia was performed at the L3-L4 interspace after epidural cannulation and epidural lidocaine was administered postoperatively, after which CSF was sampled. RESULTS: Lidocaine concentrations in CSF were significantly higher with increasing proximity of epidural injection site to CSF collection site in both groups. There were no significant differences in CSF lidocaine concentrations between group CSEA and group Epi in set I, although lidocaine concentrations were significantly higher in group CSEA set II and III patients. CONCLUSION: Lidocaine concentration in CSF was similar with or without preceding meningeal puncture beneath the epidural administration site.


Assuntos
Anestesia Epidural/métodos , Raquianestesia/métodos , Lidocaína/administração & dosagem , Lidocaína/líquido cefalorraquidiano , Adulto , Feminino , Humanos , Pessoa de Meia-Idade
16.
Jpn J Infect Dis ; 61(1): 58-64, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18219136

RESUMO

We identified seven distinct subtypes of enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates that were derived from sporadic cases and outbreaks from multiple prefectures in Japan in 2005. A surveillance system utilizing pulsed-field gel electrophoresis (PFGE), PulseNet Japan, was used. Some strains showed indistinguishable PFGE patterns using another restriction enzyme (BlnI or SpeI) in each subtype of EHEC O157:H7 isolates that were routinely subtyped by the XbaI PFGE pattern. In order to examine the genotypic relatedness of these strains, we carried out a multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA). By using the MLVA system, we found that three of seven subtypes of EHEC O157:H7 strains that were isolated from sporadic cases dispersed across multiple prefectures within a few months showed indistinguishable PFGE patterns and identical MLVA types. Strains belonging to the other four subtypes of EHEC O157:H7 in the PFGE analysis were further classified into different clusters of EHEC O157:H7. Therefore, compared to PFGE, MLVA showed greater discriminatory power with respect to analysis of the isolates in this study.


Assuntos
Escherichia coli Êntero-Hemorrágica/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Escherichia coli O157/isolamento & purificação , Repetições Minissatélites , Alelos , Técnicas de Tipagem Bacteriana , Surtos de Doenças , Eletroforese em Gel de Campo Pulsado , Escherichia coli Êntero-Hemorrágica/classificação , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/classificação , Escherichia coli O157/genética , Humanos , Japão/epidemiologia
17.
Sci Rep ; 6: 20436, 2016 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-26853703

RESUMO

We show a simple and effective way to improve the vortex irreversibility line up to very high magnetic fields (60T) by increasing the density of second phase BaZrO3 nanoparticles. (Y0.77,Gd0.23)Ba2Cu3Oy films were grown on metal substrates with different concentration of BaZrO3 nanoparticles by the metal organic deposition method. We find that upon increase of the BaZrO3 concentration, the nanoparticle size remains constant but the twin-boundary density increases. Up to the highest nanoparticle concentration (n ~ 1.3 × 10(22)/m(3)), the irreversibility field (Hirr) continues to increase with no sign of saturation up to 60 T, although the vortices vastly outnumber pinning centers. We find extremely high Hirr, namely Hirr = 30 T (H||45°) and 24 T (H||c) at 65 K and 58 T (H||45°) and 45 T (H||c) at 50K. The difference in pinning landscape shifts the vortex solid-liquid transition upwards, increasing the vortex region useful for power applications, while keeping the upper critical field, critical temperature and electronic mass anisotropy unchanged.

18.
Parasitol Int ; 65(2): 121-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26519611

RESUMO

Human African trypanosomiasis (HAT) is a disease caused by Kinetoplastid infection. Serological tests are useful for epidemiological surveillance. The aim of this study was to develop a multiplex serological assay for HAT to assess the diagnostic value of selected HAT antigens for sero-epidemiological surveillance. We cloned loci encoding eight antigens from Trypanosoma brucei gambiense, expressed the genes in bacterial systems, and purified the resulting proteins. Antigens were subjected to Luminex multiplex assays using sera from HAT and VL patients to assess the antigens' immunodiagnostic potential. Among T. b. gambiense antigens, the 64-kDa and 65-kDa invariant surface glycoproteins (ISGs) and flagellar calcium binding protein (FCaBP) had high sensitivity for sera from T. b. gambiense patients, yielding AUC values of 0.871, 0.737 and 0.858 respectively in receiver operating characteristics (ROC) analysis. The ISG64, ISG65, and FCaBP antigens were partially cross-reactive to sera from Trypanosoma brucei rhodesiense patients. The GM6 antigen was cross-reactive to sera from T. b. rhodesiense patients as well as to sera from VL patients. Furthermore, heterogeneous antibody responses to each individual HAT antigen were observed. Testing for multiple HAT antigens in the same panel allowed specific and sensitive detection. Our results demonstrate the utility of applying multiplex assays for development and evaluation of HAT antigens for use in sero-epidemiological surveillance.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Testes Sorológicos/métodos , Tripanossomíase Africana/diagnóstico , Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários/genética , Reações Cruzadas , Humanos , Curva ROC , Sensibilidade e Especificidade , Trypanosoma brucei gambiense/genética , Trypanosoma brucei gambiense/imunologia , Trypanosoma brucei rhodesiense/imunologia , Tripanossomíase Africana/sangue , Tripanossomíase Africana/imunologia
19.
PLoS Negl Trop Dis ; 9(8): e0004021, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26291988

RESUMO

BACKGROUND: Both Schistosoma mansoni and Schistosoma haematobium cause schistosomiasis in sub-Saharan Africa. We assessed the diagnostic value of selected Schistosoma antigens for the development of a multiplex serological immunoassay for sero-epidemiological surveillance. METHODOLOGY/PRINCIPAL FINDINGS: Diagnostic ability of recombinant antigens from S. mansoni and S. haematobium was assessed by Luminex multiplex immunoassay using plasma from school children in two areas of Kenya, endemic for different species of schistosomiasis. S. mansoni serine protease inhibitor (SERPIN) and Sm-RP26 showed significantly higher reactivity to patient plasma as compared to the control group. Sm-Filamin, Sm-GAPDH, Sm-GST, Sm-LAP1, Sm-LAP2, Sm-Sm31, Sm-Sm32 and Sm-Tropomyosin did not show difference in reactivity between S. mansoni infected and uninfected pupils. Sm-RP26 was cross-reactive to plasma from S. haematobium patients, whereas Sm-SERPIN was species-specific. Sh-SEPRIN was partially cross-reactive to S. mansoni infected patients. ROC analysis for Sm-RP26, Sm-SERPIN and Sh-SERPIN showed AUC values of 0.833, 0.888 and 0.947, respectively. Using Spearman's rank correlation coefficient analysis, we also found significant positive correlation between the number of excreted eggs and median fluorescence intensity (MFI) from the multiplex immunoassays for Sm-SERPIN (ρ = 0.430, p-value = 0.003) and Sh-SERPIN (ρ = 0.433, p-value = 0.006). CONCLUSIONS/SIGNIFICANCE: Sm-SERPIN is a promising species-specific diagnostic antigen. Sh-SEPRIN was partially cross-reactive to S. mansoni infected patients. SERPINs showed correlation with the number of excreted eggs. These indicate prospects for inclusion of SERPINs in the multiplex serological immunoassay system.


Assuntos
Antígenos de Helmintos/sangue , Imunoensaio/métodos , Schistosoma haematobium/imunologia , Schistosoma mansoni/imunologia , Esquistossomose Urinária/diagnóstico , Esquistossomose mansoni/diagnóstico , Inibidores de Serina Proteinase/sangue , Serpinas/sangue , Sequência de Aminoácidos , Animais , Anticorpos Anti-Helmínticos/sangue , Anticorpos Anti-Helmínticos/imunologia , Antígenos de Helmintos/genética , Antígenos de Helmintos/imunologia , Reações Cruzadas , Estudos Transversais , Feminino , Humanos , Quênia , Masculino , Dados de Sequência Molecular , Schistosoma haematobium/genética , Schistosoma haematobium/isolamento & purificação , Schistosoma mansoni/genética , Schistosoma mansoni/isolamento & purificação , Esquistossomose Urinária/sangue , Esquistossomose Urinária/parasitologia , Esquistossomose mansoni/sangue , Esquistossomose mansoni/parasitologia , Inibidores de Serina Proteinase/genética , Inibidores de Serina Proteinase/imunologia , Serpinas/genética , Serpinas/imunologia , Especificidade da Espécie
20.
PLoS Negl Trop Dis ; 8(7): e3040, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25078404

RESUMO

BACKGROUND: A strategy to combat infectious diseases, including neglected tropical diseases (NTDs), will depend on the development of reliable epidemiological surveillance methods. To establish a simple and practical seroprevalence detection system, we developed a microsphere-based multiplex immunoassay system and evaluated utility using samples obtained in Kenya. METHODS: We developed a microsphere-based immuno-assay system to simultaneously measure the individual levels of plasma antibody (IgG) against 8 antigens derived from 6 pathogens: Entamoeba histolytica (C-IgL), Leishmania donovani (KRP42), Toxoplasma gondii (SAG1), Wuchereria bancrofti (SXP1), HIV (gag, gp120 and gp41), and Vibrio cholerae (cholera toxin). The assay system was validated using appropriate control samples. The assay system was applied for 3411 blood samples collected from the general population randomly selected from two health and demographic surveillance system (HDSS) cohorts in the coastal and western regions of Kenya. The immunoassay values distribution for each antigen was mathematically defined by a finite mixture model, and cut-off values were optimized. FINDINGS: Sensitivities and specificities for each antigen ranged between 71 and 100%. Seroprevalences for each pathogen from the Kwale and Mbita HDSS sites (respectively) were as follows: HIV, 3.0% and 20.1%; L. donovani, 12.6% and 17.3%; E. histolytica, 12.8% and 16.6%; and T. gondii, 30.9% and 28.2%. Seroprevalences of W. bancrofti and V. cholerae showed relatively high figures, especially among children. The results might be affected by immunological cross reactions between W. bancrofti-SXP1 and other parasitic infections; and cholera toxin and the enterotoxigenic E. coli (ETEC), respectively. INTERPRETATION: A microsphere-based multi-serological assay system can provide an opportunity to comprehensively grasp epidemiological features for NTDs. By adding pathogens and antigens of interest, optimized made-to-order high-quality programs can be established to utilize limited resources to effectively control NTDs in Africa.


Assuntos
Doenças Transmissíveis/diagnóstico , Doenças Transmissíveis/epidemiologia , Monitoramento Epidemiológico , Testes Sorológicos , Adolescente , Adulto , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Anti-Helmínticos/sangue , Anticorpos Antiprotozoários/sangue , Criança , Pré-Escolar , Feminino , Anticorpos Anti-HIV/sangue , Humanos , Lactente , Recém-Nascido , Quênia , Masculino , Microesferas , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , Adulto Jovem
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