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831.
832.
Walter Cano Cardona Wil De Jong René G. A. Boot Pieter A. Zuidema 《Human ecology: an interdisciplinary journal》2014,42(4):541-549
The debt-peonage system is an agreement between patrons and laborers in different economic activities worldwide. A common feature is social exploitation of laborers that generate profits to the patrons. In recent literature it has been argued that debt-peonage can be an economically sound arrangement that secures the needs of actors. The paper evaluates to what extent traditionally strong debt-peonage in forest-dwelling communities in the Bolivian Amazon, has developed in a way that better secures the needs and economic interest of multiple actors. Case studies in sixteen communities yielded qualitative information on debt relations between peasants, traders and former patrons. Debt-peonage changed from a mechanism to provide and keep workforce indebted to new social relationships, equitable commercial links, opportunity to access work capital and production chain diversification. This rapid shift was caused by important changes in land and forest regulations. 相似文献
833.
Patricia Basurto‐Lozada Christian Molina‐Aguilar Carolina Castaneda‐Garcia Martha Estefania Vzquez‐Cruz Omar Isaac Garcia‐Salinas Alethia lvarez‐Cano Hctor Martínez‐Said Rodrigo Roldn‐Marín David J. Adams Patricia A. Possik Carla Daniela Robles‐Espinoza 《Pigment cell & melanoma research》2021,34(1):59-71
Acral lentiginous melanoma is a histological subtype of cutaneous melanoma that occurs in the glabrous skin of the palms, soles and the nail unit. Although in some countries, particularly in Latin America, Africa and Asia, it represents the most frequently diagnosed subtype of the disease, it only represents a small proportion of melanoma cases in European‐descent populations, which is partially why it has not been studied to the same extent as other forms of melanoma. As a result, its unique genomic drivers remain comparatively poorly explored, as well as its causes, with current evidence supporting a UV‐independent path to tumorigenesis. In this review, we discuss current knowledge of the aetiology and diagnostic criteria of acral lentiginous melanoma, as well as its epidemiological and histopathological characteristics. We also describe what is known about the genomic landscape of this disease and review the available biological models to explore potential therapeutic targets. 相似文献
834.
835.
Antonio G. González José J. Mendoza Javier G. Luis Angel G. Ravelo Xorge A. Domínguez G. Cano 《Phytochemistry》1985,24(12):3056-3058
The investigation of Palafoxia texana afforded in addition to the known compound jesromotetrol two new rosene derivatives: 3β-acetoxy-jesromotetrol and 3β,19-diacetoxy-jesromotetrol. The structures were determined by spectroscopic methods and chemical transformations. 相似文献
836.
837.
Hydroquinone (HQ), a reactive metabolite of benzene, is known to inhibit mitogen-stimulated activation of both T and B lymphocytes.
Despite extensive study, the underlying mechanism for the immunotoxicity of the HQ is not clear. We have previously demonstrated
that 1 μmol/L HQ inhibits TNF-induced activation of NFκB in CD4+ T cells, resulting in decreased IL-2 production. NFκB, known to be important in T lymphocytes, also plays a critical role
in normal B cell development and activation. We therefore hypothesized that alterations in NFκB might be involved in HQ-induced
B cell immunosuppression as well. In this study, we demonstrate that 1–10 μmol/L HQ inhibits PMA/ionomycin-induced activation
of NFκB in primary human CD19+ B cells. Inhibition of NFκB is accompanied by a dose-dependent decrease in PMA-stimulated production of TNF with no corresponding
loss in viability or increased apoptosis. HQ also does not appear to alter NFκB directly, as preincubation of B cell nuclear
extracts with HQ does not diminish DNA binding activity of this protein. In contrast to T cells, inhibition of NFκB by HQ
in B cells is not reversible after 72 h in culture, suggesting a long-term functional suppression. These data support our
original findings in T cells and indicate that NFκB is particularly susceptible to inhibition by HQ. We further hypothesize
that inhibition of NFκB in lymphocytes, and perhaps other cell types as well, may play a significant role in the observed
toxicity of HQ.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
838.
David A. Cano M. Graciela Pucciarelli Francisco García-del Portillo Josep Casadesús 《Journal of bacteriology》2002,184(2):592-595
Mutants of Salmonella enterica lacking the RecBC function are avirulent in mice and unable to grow inside macrophages (N. A. Buchmeier, C. J. Lipps, M. Y. H. So, and F. Heffron, Mol. Microbiol. 7:933-936, 1993). The virulence-related defects of RecBC(-) mutants are not suppressed by sbcB and sbcCD mutations, indicating that activation of the RecF recombination pathway cannot replace the virulence-related function(s) of RecBCD. Functions of the RecF pathway such as RecJ and RecF are not required for virulence. Since the RecBCD pathway, but not the RecF pathway, is known to participate in the repair of double-strand breaks produced during DNA replication, we propose that systemic infection by S. enterica may require RecBCD-mediated recombinational repair to prime DNA replication inside phagocytes. Mutants lacking both RecD and RecJ are also attenuated in mice and are unable to proliferate in macrophages, suggesting that exonucleases V and IX provide alternative functions for RecBCD-mediated recombinational repair during Salmonella infection. 相似文献
839.
840.