2,448 research outputs found

    Fluoromycobacteriophages for rapid, specific, and sensitive antibiotic susceptibility testing of Mycobacterium tuberculosis

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    Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. © 2009 Piuri et al

    A coalgebraic view of bar recursion and bar induction

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    We reformulate the bar recursion and induction principles in terms of recursive and wellfounded coalgebras. Bar induction was originally proposed by Brouwer as an axiom to recover certain classically valid theorems in a constructive setting. It is a form of induction on non- wellfounded trees satisfying certain properties. Bar recursion, introduced later by Spector, is the corresponding function defnition principle. We give a generalization of these principles, by introducing the notion of barred coalgebra: a process with a branching behaviour given by a functor, such that all possible computations terminate. Coalgebraic bar recursion is the statement that every barred coalgebra is recursive; a recursive coalgebra is one that allows defnition of functions by a coalgebra-to-algebra morphism. It is a framework to characterize valid forms of recursion for terminating functional programs. One application of the principle is the tabulation of continuous functions: Ghani, Hancock and Pattinson defned a type of wellfounded trees that represent continuous functions on streams. Bar recursion allows us to prove that every stably continuous function can be tabulated to such a tree where by stability we mean that the modulus of continuity is also continuous. Coalgebraic bar induction states that every barred coalgebra is well-founded; a wellfounded coalgebra is one that admits proof by induction

    The pathology of familial breast cancer: The pre-BRCA1/BRCA2 era - historical perspectives

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    A proportion of breast carcinomas develop as a result of a genetic predispostion to the disease. Prior to cloning of the BRCA1 and BRCA2 genes a limited number of studies were carried out to identify specific histopathological characteristics of hereditary breast cancer. These studies are the subject of this review. The main finding was the association of the (atypical) medullary type of breast cancer with a family history; the most important caveat being that medullary breast cancer is found more frequently in young patients. In view of the frequent bilateral occurrence of lobular cancer, this histologic type is also likely to be associated with a predisposing genetic defect. Future investigations will have to test this hypothesis. In addition to mutations in the BRCA1 and BRCA2 genes, there are as yet unidentified genetic defects predisposing to breast cancer development, and histopathology may well help in identifying these genes in the future

    Longer fixation duration while viewing face images

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    The spatio-temporal properties of saccadic eye movements can be influenced by the cognitive demand and the characteristics of the observed scene. Probably due to its crucial role in social communication, it is argued that face perception may involve different cognitive processes compared with non-face object or scene perception. In this study, we investigated whether and how face and natural scene images can influence the patterns of visuomotor activity. We recorded monkeys’ saccadic eye movements as they freely viewed monkey face and natural scene images. The face and natural scene images attracted similar number of fixations, but viewing of faces was accompanied by longer fixations compared with natural scenes. These longer fixations were dependent on the context of facial features. The duration of fixations directed at facial contours decreased when the face images were scrambled, and increased at the later stage of normal face viewing. The results suggest that face and natural scene images can generate different patterns of visuomotor activity. The extra fixation duration on faces may be correlated with the detailed analysis of facial features

    Human papillomavirus type 18 infection in a female renal allograft recipient : a case report

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    Publisher Copyright: © 2016 The Author(s).Background: Human papillomavirus type 18 is the second most common cause of cervical cancer and is found in 7 to 20 % of cases of cervical cancer. The oncogenic potential of high-risk human papillomavirus is associated with expression of early proteins E6 and E7. Due to long-term immunosuppressive therapy, renal transplant recipients have a higher risk of developing persistent human papillomavirus infection. Case presentation: A 29-year-old white woman from Latvia with chronic focal segmental glomerulosclerosis received renal allograft transplantation and was prescribed immunosuppressive therapy with cyclosporine, prednisolone, and mycophenolate mofetil. Two weeks after renal transplantation, her cervical swab was positive for human papillomavirus consensus sequences. After 6 months, quantitative polymerase chain reaction showed a high viral load of 3,630,789 copies/105 cells of high-risk human papillomavirus type 18 and expression of E6 and E7 oncogenes in her cervical swab and urine sample. One year after renal transplantation, the viral load in her cervical swab increased significantly to 7,413,102 copies/105 cells. Messenger ribonucleic acid of human papillomavirus type 18 E6 and E7 oncogenes were also detected. Shortly after this, she had an unsuccessful pregnancy which resulted in a spontaneous abortion at 6/7 weeks. Two months after the abortion her viral load sharply decreased to 39 copies/105 cells. Oncogenes E6 and E7 messenger ribonucleic acid expression was not observed in this period. Conclusions: This case report represents data which show that immunosuppressive therapy may increase the risk of developing persistent high-risk human papillomavirus infection with expression of E6 and E7 oncogenes in renal transplant recipients. However, even during this therapy the immune status of a recipient can improve and contribute to human papillomavirus viral load reduction. Spontaneous abortion can be considered a possible contributory factor in human papillomavirus clearance.publishersversionPeer reviewe

    Stability of oligosaccharides derived from lactulose during the processing of milk and apple juice

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    The scientific evidence on the bioactivity of oligosaccharides from lactulose has encouraged us to study their physicochemical modifications during the processing of milk and apple juice. The carbohydrate fraction with a degree of polymerization ≥3 was stable in milk heated at temperatures up to 100°C for 30 min and in apple juice heated up to 90°C for 15 min. An assessment of the Maillard reaction in heated milk pointed out a higher formation of furosine in milk with oligosaccharides from lactulose as compared to its counterpart without this ingredient, due to a higher presence of galactose. The organoleptic properties of juice with oligosaccharides from lactulose were acceptable and similar to those of apple juice with commercial galactooligosaccharides. The results presented herein demonstrate that oligosaccharides from lactulose can be used as prebiotic ingredients in a wide range of functional foods, including those intended for diabetics and lactose intolerant individuals.This work has been supported by project AGL2011-27884 from Spanish Ministerio de Economía y Competitividad.Peer Reviewe

    The Polycomb Repressive Complex 2 Is a Potential Target of SUMO Modifications

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    The Polycomb Repressive Complex 2 (PRC2) functions as a transcriptional repressor through a mechanism that involves methylation of Histone H3 at lysine 27. The PRC2 complex activity is essential for cellular proliferation, development, and cell fate decisions. PRC2 target genes include important regulators of development and proliferation as well as tumor suppressor genes. Consistent with this, the activity of several Polycomb group (PcG) proteins is deregulated in human cancer suggesting an important role for PcGs in tumor development. Whereas the downstream functions of PcGs are well characterized, the mechanisms of their recruitment to target genes and the regulation of their activity are not fully understood.Here we show that the two PRC2 components SUZ12 and EZH2 are sumoylated in vitro and in vivo. Among several putative sumoylation sites we have mapped the major site of SUZ12 sumoylation. Furthermore, we show that SUZ12 interacts with the E2-conjugating enzyme UBC9 both in vitro and in vivo and that mutation of the SUZ12 sumoylation site does not abolish this binding. Finally, we provide evidence that the E3-ligase PIASXbeta interacts and enhances the sumoylation of SUZ12 in vivo suggesting that PIASXbeta could function as an E3-ligase for SUZ12.Taken together, our data identify sumoylation as a novel post-translational modification of components of the PRC2 complex, which could suggest a potential new mechanism to modulate PRC2 repressive activity. Further work aimed to identify the physiological conditions for these modifications will be required to understand the role of SUZ12 and EZH2 sumoylation in PcG-mediated epigenetic regulation of transcription
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