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41.
Umberto Lombardo Katherine Szabo José M. Capriles Jan-Hendrik May Wulf Amelung Rainer Hutterer Eva Lehndorff Anna Plotzki Heinz Veit 《PloS one》2013,8(8)
We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region’s past and offers a new context within which the late Holocene “Earthmovers” of the Llanos de Moxos could have emerged. 相似文献
42.
D. R. Monteiro L. F. Gorup S. Silva M. Negri E. R. de Camargo R. Oliveira 《Biofouling》2013,29(7):711-719
The aim of this study was to evaluate the effect of silver nanoparticles (SN) against Candida albicans and Candida glabrata adhered cells and biofilms. SN (average diameter 5 nm) were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. Minimal inhibitory concentration (MIC) tests were performed for C. albicans (n = 2) and C. glabrata (n = 2) grown in suspension following the Clinical Laboratory Standards Institute microbroth dilution method. SN were applied to adhered cells (2 h) or biofilms (48 h) and after 24 h of contact their effect was assessed by enumeration of colony forming units (CFUs) and quantification of total biomass (by crystal violet staining). The MIC results showed that SN were fungicidal against all strains tested at very low concentrations (0.4–3.3 μg ml?1). Furthermore, SN were more effective in reducing biofilm biomass when applied to adhered cells (2 h) than to pre-formed biofilms (48 h), with the exception of C. glabrata ATCC, which in both cases showed a reduction ~90%. Regarding cell viability, SN were highly effective on adhered C. glabrata and respective biofilms. On C. albicans the effect was not so evident but there was also a reduction in the number of viable biofilm cells. In summary, SN may have the potential to be an effective alternative to conventional antifungal agents for future therapies in Candida-associated denture stomatitis. 相似文献
43.
Mitochondria isolated from engineered mice lacking Cyclophilin D (CypD), a component of the Permeability Transition Pore (PTP) complex, can still undergo a Ca2?+?-dependent but Cyclosporin A-insensitive permeabilization of the inner membrane. Higher Ca2?+? concentrations are required than for wild-type controls. The characteristics of the pore formed in this system were not known, and it has been proposed that they might differ substantially from those of the normal PTP. To test this hypothesis, we have characterized the PTP of isogenic wild-type and CypD? mouse liver mitochondria in patch clamp experiments, which allow biophysical characterization. The pores observed in the two cases, very similar to those of rat liver mitochondria, are indistinguishable according to a number of criteria. The only clear difference is in their sensitivity to Cyclosporin A. CypD is thus shown to be an auxiliary, modulatory component of the “standard” PTP, which forms and has essentially the same properties even in its absence. The observations suggest that Ca2?+?, CypD, and presumably other inducers and inhibitors act at the level of an activation or assembly process. Activation is separate and upstream of the gating observable on a short or medium-term time scale. Once the pore is activated, its molecular dynamics and biophysical properties may thus be predicted not to depend on the details of the induction process. 相似文献
44.
Umberto Raucci Rossella Rossi Roberto Da Cas Concita Rafaniello Nadia Mores Giulia Bersani Antonino Reale Nicola Pirozzi Francesca Menniti-Ippolito Giuseppe Traversa Italian Multicenter Study Group for Vaccine Safety in Drug Children 《PloS one》2013,8(7)
Objective
Stevens-Johnson Syndrome (SJS) is one of the most severe muco-cutaneous diseases and its occurrence is often attributed to drug use. The aim of the present study is to quantify the risk of SJS in association with drug and vaccine use in children.Methods
A multicenter surveillance of children hospitalized through the emergency departments for acute conditions of interest is currently ongoing in Italy. Cases with a diagnosis of SJS were retrieved from all admissions. Parents were interviewed on child’s use of drugs and vaccines preceding the onset of symptoms that led to the hospitalization. We compared the use of drugs and vaccines in cases with the corresponding use in a control group of children hospitalized for acute neurological conditions.Results
Twenty-nine children with a diagnosis of SJS and 1,362 with neurological disorders were hospitalized between 1st November 1999 and 31st October 2012. Cases were more frequently exposed to drugs (79% vs 58% in the control group; adjusted OR 2.4; 95% CI 1.0–6.1). Anticonvulsants presented the highest adjusted OR: 26.8 (95% CI 8.4–86.0). Significantly elevated risks were also estimated for antibiotics use (adjusted OR 3.3; 95% CI 1.5–7.2), corticosteroids (adjusted OR 4.2; 95% CI 1.8–9.9) and paracetamol (adjusted OR 3.2; 95% CI 1.5–6.9). No increased risk was estimated for vaccines (adjusted OR: 0.9; 95% CI 0.3–2.8).Discussion
Our study provides additional evidence on the etiologic role of drugs and vaccines in the occurrence of SJS in children. 相似文献45.
Osteoarthritis (OA) is a chronic disease affecting the cartilage of over 15% of Canadians. Synovial fluid mesenchymal progenitor cells (sfMPCs) are present in joints and are thought to contribute to healing. OA sfMPCs have a greater proliferative ability but decreased chondrogenic potential. However, little is known about the factors influencing/regulating the differences between normal and OA sfMPCs. Recently, our lab has shown that sfMPC chondrogenic differentiation in vitro is favorably biased toward a similar osmotic environment as they experience in vivo. The current study now examines the expression and functionality of a variety of ion channels in sfMPCs derived from normal individuals and early OA patients. Results indicated that there is differential ion channel regulation at the functional level and expression level in early OA sfMPCs. All ion channels were upregulated in early OA compared to normal sfMPCs with the exception of KCNMA1 at the mRNA level. At the protein level, TRPV4 was over expressed in early OA sfMPCs, while KCNJ12 and KCNMA1 were unchanged between normal and early OA sfMPCs. At the functional level, the inward rectifying potassium channel was under expressed in early OA sfMPCs, however the membrane potential was unchanged between normal and early OA sfMPCs. In the synovial environment itself, a number of differences in ion concentration between normal and early OA synovial fluid were observed. These findings suggest that normal and OA progenitor cells demonstrate functional differences in how they interact with the synovial ion environment. 相似文献
46.
Baldassa S Gnesutta N Fascio U Sturani E Zippel R 《The Journal of biological chemistry》2007,282(4):2333-2345
RasGRF1 is a neuron-specific guanine nucleotide exchange factor for the small GTPases Ras and Rac. It is implicated in the regulation of memory formation and in the development of tolerance to drug abuse, although the mechanisms have been elucidated only in part. Here we report the isolation, by the yeast two-hybrid screen, of the microtubule-destabilizing factor SCLIP (SCG10-like protein) as a novel RasGRF1-interacting protein. This interaction requires the region spanning the Dbl-homology domain of RasGRF1, endowed with catalytic activity on Rac. In search for a possible function we found by biochemical means that SCLIP influences the signaling properties of RasGRF1, greatly reducing its ability to activate the Rac/p38 MAPK pathway, while the Ras/Erk one remains unaffected. Moreover, a potential role is suggested by transfection studies in neuronal PC12 cells in which RasGRF1 induces neurite outgrowth, and coexpression of SCLIP counteracts this effect, causing a dramatic decrease in the percentage of cells bearing neurites, which also appear significantly shortened. This study unveils a physical and functional interaction between RasGRF1 and SCLIP. We suggest that this novel interplay may have possible implications in mechanisms that regulate neuronal morphology and structural plasticity. 相似文献
47.
48.
49.
Negri R Buttinelli M Panetta G De Arcangelis V Di Mauro E Travers A 《Journal of molecular biology》2001,307(4):987-999
The basis for the choice of translational position of a histone octamer on DNA is poorly understood. To gain further insights into this question we have studied the translational and rotational settings of core particles assembled on a simple repeating 20 bp positioning sequence. We show that the translational positions of the core particles assembled on this sequence are invariant with respect to the DNA sequence and occur at 20 bp intervals. Certain modifications of the original sequence reduce the spacing of possible dyads to 10 bp. At least one of these alters both the translational and rotational settings. We conclude that the translational position of a core particle is specified by sequence determinants additional to those specifying rotational positioning. The rotational settings on either side of the dyads of core particles assembled on the wild-type and a mutant sequence differ by +2 bp, corresponding to an overall helical periodicity of approximately 10.15 bp. The average helical periodicity of the central two to four turns is 10.5-11 bp whilst that of the flanking DNA is closer to 10 bp. The DNA immediately flanking the dyad is also characterised by a more extensive susceptibility to cleavage by hydroxyl radical. 相似文献
50.
Differential involvement of DNases in HeLa cell apoptosis induced by etoposide and long term-culture
Torriglia A Negri C Chaudun E Prosperi E Courtois Y Counis MF Scovassi AI 《Cell death and differentiation》1999,6(3):234-244
We have applied to human HeLa cells two different stimuli of apoptosis: the antitumoral drug etoposide, and a more 'physiological' death condition, obtained by growing cells in the same medium for long time periods, for up to 10 days. Analysis of different parameters demonstrated that in both experimental systems the same apoptotic features are visible. However, the DNA degradation pattern appeared to be different, suggesting the involvement of different DNases. In this view, we have analyzed the activity and expression of Ca2+-Mg2+-dependent and acid DNases. We have observed that DNase I is not modulated during apoptosis. In contrast, the acid L-DNase II (derived from Leukocyte Elastase Inhibitor by post-translational modification), recently identified in our laboratory, is mainly active in the apoptotic pathway induced by long term-culture. Furthermore, we have provided evidence that while caspase 3 is activated by both inducers, caspase 1 is essential only for the etoposide-induced apoptosis. 相似文献