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1.
J Med Internet Res ; 25: e44641, 2023 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-37498666

RESUMEN

BACKGROUND: The minimum data set (MDS) is a collection of data elements to be grouped using a standard approach to allow the use of data for clinical and research purposes. Health data are typically voluminous, complex, and sometimes too ambiguous to generate indicators that can provide knowledge and information on health. This complexity extends further to the rare disease (RD) domain. MDSs are essential for health surveillance as they help provide services and generate recommended population indicators. There is a bottleneck in international literature that reveals a global problem with data collection, recording, and structuring in RD. OBJECTIVE: This study aimed to identify and analyze the MDSs used for RD in health care networks worldwide and compare them with World Health Organization (WHO) guidelines. METHODS: The population, concept, and context methodology proposed by the Joanna Briggs Institute was used to define the research question of this systematic review. A total of 4 databases were reviewed, and all the processes were reported using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. The data elements were analyzed, extracted, and organized into 10 categories according to WHO digital health guidelines. The quality assessment used the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist. RESULTS: We included 20 studies in our review, 70% (n=14) of which focused on a specific health domain and 30% (n=6) of which referred to RD in general. WHO recommends that health systems and networks use standard terminology to exchange data, information, knowledge, and intelligence in health. However, there was a lack of terminological standardization of the concepts in MDSs. Moreover, the selected studies did not follow the same standard structure for classifying the data from their MDSs. All studies presented MDSs with limitations or restrictions because they covered only a specific RD, or their scope of application was restricted to a specific context or geographic region. Data science methods and clinical experience were used to design, structure, and recommend a fundamental global MDS for RD patient records in health care networks. CONCLUSIONS: Our study highlights the difficulties in standardizing and categorizing findings from MDSs for RD because of the varying structures used in different studies. The fundamental RD MDS designed in this study comprehensively covers the data needs in the clinical and management sectors. These results can help public policy makers support other aspects of their policies. We highlight the potential of our results to help strategic decisions related to RD. TRIAL REGISTRATION: PROSPERO CRD42021221593; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=221593. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1016/j.procs.2021.12.034.


Asunto(s)
Personal Administrativo , Enfermedades Raras , Humanos , Enfermedades Raras/terapia , Lista de Verificación , Ciencia de los Datos , Política Pública
2.
Proc Natl Acad Sci U S A ; 112(18): 5625-30, 2015 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-25902511

RESUMEN

We report directly dated evidence from circa 1400 calibrated years (cal) B.C. for the early use of wheat, barley, and flax as staple crops on the borders of the Tibetan Plateau. During recent years, an increasing amount of data from the Tibetan Plateau and its margins shows that a transition from millets to wheat and barley agriculture took place during the second millennium B.C. Using thermal niche modeling, we refute previous assertions that the ecological characteristics of wheat and barley delayed their spread into East Asia. Rather, we demonstrate that the ability of these crops to tolerate frost and their low growing degree-day requirements facilitated their spread into the high-altitude margins of western China. Following their introduction to this region, these crops rapidly replaced Chinese millets and became the staple crops that still characterize agriculture in this area today.


Asunto(s)
Agricultura/métodos , Productos Agrícolas/crecimiento & desarrollo , Hordeum/crecimiento & desarrollo , Triticum/crecimiento & desarrollo , Adaptación Fisiológica , Agricultura/tendencias , Altitud , China , Ecosistema , Geografía , Humanos , Paleontología/métodos , Tibet , Factores de Tiempo
3.
J Immunol ; 194(9): 4362-70, 2015 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-25821220

RESUMEN

Regulatory T cells (Tregs) are a subset of CD4(+) T cells that maintain immune tolerance in part by their ability to inhibit the proliferation of conventional CD4(+) T cells (Tconvs). The role of the TCR and the downstream signaling pathways required for this suppressive function of Tregs are not fully understood. To yield insight into how TCR-mediated signals influence Treg suppressive function, we assessed the ability of Tregs with altered TCR-mediated signaling capacity to inhibit Tconv proliferation. Mature Tregs deficient in Src homology 2 domain containing leukocyte protein of 76 kDa (SLP-76), an adaptor protein that nucleates the proximal signaling complex downstream of the TCR, were unable to inhibit Tconv proliferation, suggesting that TCR signaling is required for Treg suppressive function. Moreover, Tregs with defective phospholipase C γ (PLCγ) activation due to a Y145F mutation of SLP-76 were also defective in their suppressive function. Conversely, enhancement of diacylglycerol-mediated signaling downstream of PLCγ by genetic ablation of a negative regulator of diacylglycerol kinase ζ increased the suppressive ability of Tregs. Because SLP-76 is also important for integrin activation and signaling, we tested the role of integrin activation in Treg-mediated suppression. Tregs lacking the adaptor proteins adhesion and degranulation promoting adapter protein or CT10 regulator of kinase/CT10 regulator of kinase-like, which are required for TCR-mediated integrin activation, inhibited Tconv proliferation to a similar extent as wild-type Tregs. Together, these data suggest that TCR-mediated PLCγ activation, but not integrin activation, is required for Tregs to inhibit Tconv proliferation.


Asunto(s)
Inmunomodulación , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismo , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Diglicéridos/metabolismo , Integrinas/metabolismo , Ratones , Ratones Transgénicos , Fosfoproteínas/metabolismo , Receptores de Antígenos de Linfocitos T/genética
4.
Blood ; 119(23): 5575-83, 2012 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-22496155

RESUMEN

FoxP3(+) regulatory T cells (Tregs) suppress GVHD while preserving graft-versus-tumor effects, making them an attractive target for GVHD therapy. The donor-derived Treg pool can potentially be derived from the expansion of preexisting natural Tregs (nTregs) or from de novo generation of inducible Tregs (iTregs) from donor Tconvs in the transplantation recipient. Using an MHC-mismatched model of acute GVHD, in the present study we found that the Treg pool was comprised equally of donor-derived nTregs and iTregs. Experiments using various combinations of T cells from wild-type and FoxP3-deficient mice suggested that both preexisting donor nTregs and the generation of iTregs in the recipient mice contribute to protection against GVHD. Surprisingly, CD8(+)FoxP3(+) T cells represented approximately 70% of the iTreg pool. These CD8(+)FoxP3(+) T cells shared phenotypic markers with their CD4(+) counterparts and displayed suppressive activity, suggesting that they were bona fide iTregs. Both CD4(+) and CD8(+) Tregs appeared to be protective against GVHD-induced lethality and required IL-2 and TGFß receptor expression for their generation. These data illustrate the complex makeup of the donor-derived FoxP3(+) Treg pool in allogeneic recipients and their potential role in protection against GVHD.


Asunto(s)
Antígenos CD4/inmunología , Linfocitos T CD4-Positivos/inmunología , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Enfermedad Injerto contra Huésped/inmunología , Receptores de Interleucina-2/inmunología , Receptores de Factores de Crecimiento Transformadores beta/inmunología , Animales , Factores de Transcripción Forkhead/inmunología , Ratones , Ratones Endogámicos C57BL
5.
J Immunol ; 189(1): 28-32, 2012 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-22623329

RESUMEN

To ensure immune tolerance, regulatory T cell (Treg) numbers must be maintained by cell division. This process has been thought to be strictly dependent on the Treg TCR interacting with MHC class II. In this study, we report that Treg division does not absolutely require cell-autonomous TCR signaling in vivo, depending on the degree of IL-2-mediated stimulation provided. At steady state IL-2 levels, Tregs require cell-autonomous TCR signaling to divide. However, when given exogenous IL-2 or when STAT5 is selectively activated in Tregs, Treg division can occur independently of MHC class II and TCR signaling. Thus, depending on the amount of IL-2R stimulation, a wide range of TCR signals supports Treg division, which may contribute to preservation of a diverse repertoire of Treg TCR specificities. These findings also have therapeutic implications, as TCR signaling by Tregs may not be required when using IL-2 to increase Treg numbers for treatment of inflammatory disorders.


Asunto(s)
Proliferación Celular , Interleucina-2/fisiología , Receptores de Antígenos de Linfocitos T/fisiología , Transducción de Señal/inmunología , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismo , Traslado Adoptivo , Animales , Presentación de Antígeno/genética , Presentación de Antígeno/inmunología , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/trasplante , División Celular/genética , División Celular/inmunología , Homeostasis/genética , Homeostasis/inmunología , Ratones , Ratones Noqueados , Ratones Transgénicos , Receptores de Interleucina-2/fisiología , Transducción de Señal/genética , Linfocitos T Reguladores/citología
6.
J Autoimmun ; 44: 13-20, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23834842

RESUMEN

Strategies to expand regulatory T cells hold therapeutic potential for ameliorating T cell-mediated autoimmunity. Recently, we reported that the requirements for T cell receptor signaling in conventional T cell and regulatory T cell proliferation are different. Using mutant mice that display defective T cell receptor-mediated phospholipase Cγ (PLCγ) activation, we hereby demonstrate that PLCγ activation is required for antigen-specific conventional T cell proliferation but not for IL-2-induced regulatory T cell proliferation. This led us to hypothesize that in conjunction with IL-2, pharmacological inhibition of T cell receptor-mediated PLCγ activation might offer a novel therapeutic strategy to expand regulatory T cells while simultaneously inhibiting conventional T cell proliferation. Indeed, using the calcineurin inhibitor Cyclosporine A to inhibit signaling downstream of PLCγ, we found that Cyclosporine A attenuated antigen-specific Tconv proliferation but permitted IL-2-induced regulatory T cell expansion in vitro and in vivo. Furthermore, the combination of Cyclosporine A and IL-2 was superior over either Cyclosporine A or IL-2 monotherapy in protection against the T cell-mediated demyelinating autoimmune disease mouse model, experimental autoimmune encephalomyelitis. Thus, a combination of TCR signaling inhibition and IL-2 might be a beneficial strategy in expanding regulatory T cells and inhibiting conventional T cell proliferation in autoimmune settings.


Asunto(s)
Interleucina-2/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Traslado Adoptivo , Secuencia de Aminoácidos , Animales , Autoinmunidad/inmunología , Procesos de Crecimiento Celular/inmunología , Ciclosporina/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/metabolismo , Interleucina-2/metabolismo , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal/inmunología , Linfocitos T Reguladores/metabolismo , Fosfolipasas de Tipo C/inmunología
7.
Environ Pract ; 15(3): 350-366, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26213492

RESUMEN

China's tuigeng huanlin or "Returning Farmland to Forest" (RFFP) program has been widely praised as the world's largest and most successful payment for ecosystem services program, as well as a major contributor to China's dramatic increase in forest cover from perhaps as low as 8% in 1960 to about 21% today. By compensating rural households for the conversion of marginal farmland to forestland and financing the afforestation of barren mountainsides, the program, in addition to expanding forestland, aims to reduce soil erosion and alleviate poverty. This paper presents qualitative and quantitative studies conducted on the local implementation of RFFP in three diverse townships in Sichuan. We find the actual results to be more mixed than the official figures would indicate. Though there have been some positive results, we identify problems with site and species selection, compensation for land taken out of cultivation, shift of labor to off-farm activities, and monitoring of replanted sites, which challenge the ecological and economic impacts of these programs and reveal much of the effort of the program has been misdirected. We suggest that efforts are misplaced because of the top-down, panacea nature of the program, which in turn is a feature of Chinese bureaucratic management.

8.
Resusc Plus ; 15: 100452, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37662642

RESUMEN

Background: The COVID-19 pandemic created complex challenges regarding the timing and appropriateness of do-not-attempt cardiopulmonary resuscitation (DNACPR) and/or Do Not Intubate (DNI) code status orders. This paper sought to determine differences in utilization of DNACPR and/or DNI orders during different time periods of the COVID-19 pandemic, including prevalence, predictors, timing, and outcomes associated with having a documented DNACPR and/or DNI order in hospitalized patients with COVID-19. Methods: A cohort study of hospitalized patients with COVID-19 at two hospitals located in the Midwest. DNACPR code status orders including, DNI orders, demographics, labs, COVID-19 treatments, clinical interventions during hospitalization, and outcome measures including mortality, discharge disposition, and hospice utilization were collected. Patients were divided into two time periods (early and late) by timing of hospitalization during the first wave of the pandemic (March-October 2020). Results: Among 1375 hospitalized patients with COVID-19, 19% (n = 258) of all patients had a documented DNACPR and/or DNI order. In multivariable analysis, age (older) p =< 0.01, OR 1.12 and hospitalization early in the pandemic p = 0.01, OR 2.08, were associated with having a DNACPR order. Median day from DNACPR order to death varied between cohorts p => 0.01 (early cohort 5 days versus late cohort 2 days). In-hospital mortality did not differ between cohorts among patients with DNACPR orders, p = 0.80. Conclusions: There was a higher prevalence of DNACPR and/or DNI orders and these orders were written earlier in the hospital course for patients hospitalized early in the pandemic versus later despite similarities in clinical characteristics and medical interventions. Changes in clinical care between cohorts may be due to fear of resource shortages and changes in knowledge about COVID-19.

9.
J Mech Behav Biomed Mater ; 115: 104281, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33348215

RESUMEN

Surgical mesh products made from polypropylene (PP) have been extensively used in the treatment of stress urinary incontinence, pelvic organ prolapse and other conditions. Since the onset of the use of such implants, major complications have been reported. Mesh erosion, where neighbouring tissues are worn from the rubbing of mesh, occurs in a significant number of cases. However, there is still a lack in literature exploring the mechanics of this phenomenon. In this study, a purpose-built apparatus was used to generate erosion in soft tissue (porcine muscle) through the application of a force and a reciprocating action. Four different commercial products were tested, all made from knitted PP fibres: Monarc™ Gynecare™ and Obtryx™ slings and Sutulene™ mesh sheet material. A PP suture and three PP sheets with different edge roughness were also tested. Large differences were found in the erosion rates. Significantly, we found that meshes in which the edge had been formed using heat to cause partial melting gave much higher rates of erosion than mechanically cut edges. Heat-formed edges tended to retain their shape whilst mechanically cut edges degraded by unravelling. Several features of the mesh edge appear to be significant, including roughness, flexibility and the tendency to degrade. Constant load (non-reciprocating) tests were also carried out, revealing that creep can also cause erosion. These findings have significance for the design of surgical mesh products to minimise their adverse effects.


Asunto(s)
Prolapso de Órgano Pélvico , Incontinencia Urinaria de Esfuerzo , Animales , Fenómenos Mecánicos , Prolapso de Órgano Pélvico/cirugía , Polipropilenos , Mallas Quirúrgicas , Porcinos
10.
Materials (Basel) ; 14(4)2021 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-33671160

RESUMEN

Mesh erosion is a phenomenon whereby soft tissue becomes damaged as a result of contact with implants made from surgical mesh, a fabric-like material consisting of fibers of polypropylene or other polymers. This paper describes the design and construction of a testing machine to generate mesh erosion in vitro. A sample of mesh in the form of a 10 mm wide tape is pressed against soft tissue (porcine muscle) with a given force, and a given reciprocating movement is applied between the mesh and the tissue. To demonstrate the capabilities of the equipment, we measured erosion using the same mesh and tissue type, varying the applied force and the reciprocating stroke length, including zero strokes (i.e., static loading). For comparison, we also tested four other samples of polypropylene with different edge characteristics. Analysis of the results suggests the existence of three different erosion mechanisms: cutting, wear and creep. It is concluded that the equipment provides a useful and realistic simulation of mesh erosion, a phenomenon that is of great clinical significance and merits further study.

11.
Environ Sci Pollut Res Int ; 28(32): 43507-43514, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33834340

RESUMEN

The dissemination of antibiotic resistance genes (ARGs) in the environment contributes to the global rise in antibiotic resistant infections. Therefore, it is of importance to further research the exposure pathways of these emerging contaminants to humans. This study explores commercially available garden products containing animal manure as a source of ARGs in a survey of 34 garden products, 3 recently landscaped soils, and 5 native soils. DNA was extracted from these soils and quantified for 5 ARGs, intI1, and 16S rRNA. This study found that both absolute and relative gene abundances in garden products ranged from approximately two to greater than four orders of magnitude higher than those observed in native soils. Garden products with Organic Materials Review Institute (OMRI) certification did not have significantly different ARG abundances. Results here indicate that garden products are important sources of ARGs to gardens, lawns, and parks.


Asunto(s)
Antibacterianos , Jardines , Animales , Antibacterianos/farmacología , Farmacorresistencia Microbiana/genética , Genes Bacterianos , Humanos , Estiércol , ARN Ribosómico 16S/genética , Suelo , Microbiología del Suelo
12.
J Mech Behav Biomed Mater ; 126: 104548, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34030975
13.
J Clin Invest ; 127(5): 1651-1663, 2017 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-28346226

RESUMEN

Mature B cell pools retain a substantial proportion of polyreactive and self-reactive clonotypes, suggesting that activation checkpoints exist to reduce the initiation of autoreactive B cell responses. Here, we have described a relationship among the B cell receptor (BCR), TLR9, and cytokine signals that regulate B cell responses to DNA-containing antigens. In both mouse and human B cells, BCR ligands that deliver a TLR9 agonist induce an initial proliferative burst that is followed by apoptotic death. The latter mechanism involves p38-dependent G1 cell-cycle arrest and subsequent intrinsic mitochondrial apoptosis and is shared by all preimmune murine B cell subsets and CD27- human B cells. Survival or costimulatory signals rescue B cells from this fate, but the outcome varies depending on the signals involved. B lymphocyte stimulator (BLyS) engenders survival and antibody secretion, whereas CD40 costimulation with IL-21 or IFN-γ promotes a T-bet+ B cell phenotype. Finally, in vivo immunization studies revealed that when protein antigens are conjugated with DNA, the humoral immune response is blunted and acquires features associated with T-bet+ B cell differentiation. We propose that this mechanism integrating BCR, TLR9, and cytokine signals provides a peripheral checkpoint for DNA-containing antigens that, if circumvented by survival and differentiative cues, yields B cells with the autoimmune-associated T-bet+ phenotype.


Asunto(s)
Antígenos/inmunología , Linfocitos B/inmunología , ADN/inmunología , Puntos de Control de la Fase G1 del Ciclo Celular/inmunología , Receptor Toll-Like 9/inmunología , Animales , Factor Activador de Células B/genética , Factor Activador de Células B/inmunología , Antígenos CD40/genética , Antígenos CD40/inmunología , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Línea Celular , Femenino , Puntos de Control de la Fase G1 del Ciclo Celular/genética , Interferón gamma/genética , Interferón gamma/inmunología , Interleucinas/genética , Interleucinas/inmunología , Sistema de Señalización de MAP Quinasas/genética , Sistema de Señalización de MAP Quinasas/inmunología , Masculino , Ratones , Ratones Noqueados , Receptores de Antígenos de Linfocitos B/genética , Receptores de Antígenos de Linfocitos B/inmunología , Proteínas de Dominio T Box/genética , Proteínas de Dominio T Box/inmunología , Receptor Toll-Like 9/genética , Proteínas Quinasas p38 Activadas por Mitógenos/genética , Proteínas Quinasas p38 Activadas por Mitógenos/inmunología
14.
Acta sci., Biol. sci ; Acta sci., Biol. sci;43: e56235, 2021. map, ilus, graf
Artículo en Inglés | LILACS, VETINDEX | ID: biblio-1461010

RESUMEN

After the formation of Itaipu Reservoir, the invader Trachelyopterus galeatus colonized the upper Paraná River. Light microscopy was used to describe gametogenesis and the reproductive phases of females and males. The following data were verified: diameter of the oocytes, spawning type, batch fecundity by ovary weight, standard length, and total weight of the fish, along with the regions where this species reproduced in the upper Paraná River floodplain. A total of 470 specimens were collected quarterly in 2016, 2018 and 2019, and bimonthly in 2017. The gonads were fixed in a Karnovsky solution, dehydrated, infiltrated, and embedded in historesin. The histological slides were stained using PAS + iron hematoxylin + metanil yellow, analyzed and photographed under an image-capturing microscope. As regards diameter of the oocytes and fecundity estimates, ovaries whose oocytes were measured under a stereomicroscope were sampled. In the oogenesis, undifferentiated and differentiated oogonia, early primary growth oocytes, secondary growth oocytes, full-grown oocytes and maturing oocytes were recorded. In the spermatogenesis, primary and secondary spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa were recorded. The reproductive phases found for females and males were: immature, early development, late development, spawning/sperm-releasing capable, regression, and regeneration. Trachelyopterus galeatus prefers to occupy and reproduce in the Ventura, Patos, Guaraná, Fechada, Garças, and Pau Véio lagoons. The diameter of the oocytes varied from 0.4 to 2.9 mm. Females spawn, on average, 113 oocytes per batch. Batch fecundity variation shows that the larger the ovary, standard length, and total weight, the larger the number of oocytes to be spawned. This invader possesses reproductive success in the upper Paraná River floodplain, especially in lagoons.


Asunto(s)
Animales , Espermatogénesis , Fertilidad , Inseminación , Bagres/crecimiento & desarrollo , Bagres/embriología , Reproducción
15.
J Leukoc Biol ; 98(5): 703-12, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26153417

RESUMEN

DGK-ζ is a negative regulator of TCR signaling that causes degradation of the second messenger DAG, terminating DAG-mediated activation of Ras and PKCθ. Cytotoxic T cells deficient in DGK-ζ demonstrate enhanced effector functions in vitro and antitumor activity in vivo, perhaps because of insensitivity to inhibitory cytokines. We sought to determine whether the enhanced responsiveness of DGK-ζ-deficient T cells renders them insensitive to the inhibitory cytokine TGF-ß and to determine how the loss of DGK-ζ facilitates this insensitivity. We identified decreased transcriptional and functional responses to TGF-ß in CD8(+) DGK-ζ(-/-) T cells but preserved TGF-ß-mediated conversion of naïve DGK-ζ(-/-) CD4(+) T cells to a regulatory T cell phenotype. Decreased CD8(+) T cell responsiveness to TGF-ß did not result from impaired canonical TGF-ß signal transduction, because similar levels of TGF-ß-R and intracellular Smad components were identified in WT and DGK-ζ(-/-) CD8(+) T cells, and TGF-ß-mediated activation of Smad2 was unchanged. Instead, an enhanced TCR signal strength was responsible for TGF-ß insensitivity, because (i) loss of DGK-ζ conferred resistance to TGF-ß-mediated inhibition of Erk phosphorylation, (ii) TGF-ß insensitivity could be recapitulated by exogenous addition of the DAG analog PMA, and (iii) TGF-ß sensitivity could be observed in DGK-ζ-deficient T cells at limiting dilutions of TCR stimulation. These data indicate that enhanced TCR signal transduction in the absence of DGK-ζ makes T cells relatively insensitive to TGF-ß, in a manner independent of Smads, a finding with practical implications in the development of immunotherapies that target TGF-ß.


Asunto(s)
Linfocitos T CD8-positivos/inmunología , Diacilglicerol Quinasa/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Transducción de Señal/inmunología , Factor de Crecimiento Transformador beta/inmunología , Animales , Linfocitos T CD8-positivos/citología , Diacilglicerol Quinasa/genética , Ratones , Ratones Noqueados , Receptores de Antígenos de Linfocitos T/genética , Transducción de Señal/genética , Proteína Smad2/genética , Proteína Smad2/inmunología , Factor de Crecimiento Transformador beta/genética
16.
Science ; 349(6245): 302-5, 2015 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-26185249

RESUMEN

The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents. The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity.


Asunto(s)
Biodiversidad , Pradera , Desarrollo de la Planta , Biomasa , Estrés Fisiológico
17.
PLoS One ; 9(3): e92888, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24658577

RESUMEN

Regulatory T cells (Treg)s attenuate excessive immune responses, making their expansion beneficial in immune-mediated diseases including allogeneic bone marrow transplantation (BMT)-associated graft-versus-host disease (GVHD). We have recently reported that Treg expansion does not require phospholipase Cγ activation when IL-2 is provided. As such, the combination of IL-2 and a calcineurin inhibitor (Cyclosporine A; CsA) expands Tregs while inhibiting Tconv proliferation and protects against a mouse model of multiple sclerosis. However, CsA inhibits Treg proliferation in the presence of a TCR stimulus, suggesting that CsA may negatively impact Treg proliferation when they receive strong allogeneic MHC-mediated TCR signals. In this study, we show that CsA inhibits Treg proliferation and inducible Treg generation in allogeneic but not in syngeneic BMT when IL-2 is provided. In contrast to CsA, the mTOR inhibitor (Rapamycin) almost completely suppressed IL-2-mediated Treg proliferation. However, CsA and Rapamycin inhibited Treg proliferation to a similar extent when TCR stimulation was provided. Furthermore, Rapamycin promoted Treg expansion and inducible Treg generation in allogeneic BMT recipients treated with IL-2. Consistent with these observations, CsA abrogated while Rapamycin promoted the protective effect of IL-2 on allogeneic BMT-induced GVHD. These results suggest that while CsA permits IL-2-induced Treg proliferation in the syngeneic setting (absence of strong TCR signals), CsA in combination with IL-2 may be detrimental for Treg proliferation in an allogeneic setting. Thus, in allogeneic settings, an mTOR inhibitor such as Rapamycin is a better choice for adjunct therapy with IL-2 in expansion of Tregs and protection against allogeneic BMT-induced GVHD.


Asunto(s)
Trasplante de Médula Ósea , Inhibidores de la Calcineurina , Enfermedad Injerto contra Huésped/inmunología , Interleucina-2/farmacología , Linfocitos T Reguladores/efectos de los fármacos , Linfocitos T Reguladores/inmunología , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Animales , Trasplante de Médula Ósea/efectos adversos , Calcineurina/metabolismo , Ciclosporina/farmacología , Enfermedad Injerto contra Huésped/metabolismo , Enfermedad Injerto contra Huésped/prevención & control , Inmunosupresores/farmacología , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/inmunología , Melanoma Experimental , Ratones , Receptores de Antígenos de Linfocitos T/metabolismo , Linfocitos T Reguladores/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Donantes de Tejidos , Trasplante Homólogo
18.
Hum Ecol Interdiscip J ; 42(3): 481-491, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26097267

RESUMEN

Jiuzhaigou National Park (JNP) is a site of global conservation significance. Conservation policies in JNP include the implementation of two national reforestation programs to increase forest cover and the exclusion of local land-use. We use archaeological excavation, ethnographic interviews, remote sensing and vegetation surveys to examine the implications of these policies for non-forest, montane meadows. We find that Amdo Tibetan people cultivated the valley for >2,000 years, creating and maintaining meadows through land clearing, burning and grazing. Meadows served as sites for gathering plants and mushrooms and over 40 % of contemporary species are ethnobotanically useful. Remote sensing analyses indicate a substantial (69.6 %) decline in meadow area between 1974 and 2004. Respondents report a loss of their "true history" and connections to the past associated with loss of meadows. Conservation policies intended to preserve biodiversity are unintentionally contributing to the loss of these ecologically and culturally significant meadow habitats.

19.
Sci Signal ; 6(303): ra101, 2013 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-24280042

RESUMEN

Natural regulatory T (nT(reg)) cells are important for maintaining tolerance to self- and foreign antigens, and they are thought to develop from thymocytes that receive strong T cell receptor (TCR)-mediated signals in the thymus. TCR engagement leads to the activation of phospholipase C-γ1, which generates the lipid second messenger diacylglycerol (DAG) from phosphatidylinositol 4,5-bisphosphate. We used mice that lack the ζ isoform of DAG kinase (DGKζ), which metabolizes DAG to terminate its signaling, to enhance TCR-mediated signaling and identify critical signaling events in nT(reg) cell development. Loss of DGKζ resulted in increased numbers of thymic CD25(+)Foxp3(-)CD4(+) nT(reg) cell precursors and Foxp3(+)CD4(+) nT(reg) cells in a cell-autonomous manner. DGKζ-deficient T cells exhibited increased nuclear translocation of the nuclear factor κB subunit c-Rel, as well as enhanced extracellular signal-regulated kinase (ERK) phosphorylation in response to TCR stimulation, suggesting that these downstream pathways may contribute to nT(reg) cell development. Indeed, reducing c-Rel abundance or blocking ERK phosphorylation abrogated the increased generation of nTreg cells by DGKζ-deficient thymocytes. The extent of ERK phosphorylation correlated with TCR-mediated acquisition of Foxp3 in immature thymocytes in vitro. Furthermore, the development of nT(reg) cells was augmented in mice in which ERK activation was selectively enhanced in T cells. Together, these data suggest that DGKζ regulates the development of nT(reg) cells by limiting the extent of activation of the ERK and c-Rel signaling pathways.


Asunto(s)
Diferenciación Celular/inmunología , Diacilglicerol Quinasa/deficiencia , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal/inmunología , Linfocitos T Reguladores/citología , Timo/inmunología , Animales , Western Blotting , Antígenos CD4/metabolismo , Diacilglicerol Quinasa/genética , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Citometría de Flujo , Factores de Transcripción Forkhead/metabolismo , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación , Proteínas Proto-Oncogénicas c-rel/metabolismo , Linfocitos T Reguladores/inmunología , Timo/citología
20.
J Mt Sci ; 10(5): 824-832, 2013 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-26478727

RESUMEN

This paper examines human impact on stands and individual trees of Pinus yunnanensis growing near the small mountain villages of Pianshui and Yangjuan in southwestern Sichuan Province, China. In an effort to assess whether use of these forests was sustainable, we examined the effects of human use in two ways. First, we directly measured the effect of cutting branches, for fuel and fodder, on tree growth. We hypothesized that branch cutting would negatively impact tree growth. We established 12 plots on four hills and compared 14 pairs of trees, one tree in each pair with an apparently full crown and the other with a considerable portion of the crown removed. Second, we assessed stand and tree properties over a 500 m elevation gradient above the villages where we hypothesized that as elevation increases, stand and tree properties should show fewer human impacts. Although extensive branch cutting reduced the live crown, tree height and diameter, compensatory processes likely enabled trees to recover and to add basal area increments (BAIs) similar to those added by trees with full crowns. Trees and stands close to villages showed less growth and lower basal areas, respectively, than stands and trees at intermediate or distant elevations from villages. Areas relatively close to the villages showed considerable effects of human-related disturbances such as branch cutting, grazing, tree and shrub removal, losses of litter, and human and animal trails. Such areas had increased soil erosion and often loss of the 'A' horizon. Stands close to villages had younger trees, lower stand basal areas, smaller basal area increments, and more stumps. Our results suggest an increasingly vulnerable interface between occupants of these two villages and their surrounding forests.

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