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Activity Capable (activity + capable)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

The Flexible and the Pliant: Disturbed Organisms of Soviet Modernity

CULTURAL ANTHROPOLOGY, Issue 3 2004
Serguei Alex.
In the texts of prominent Soviet figures such as writer Maxim Gorky, the agrobiologist Trofim Lysenko, and the educator Anton Makarenko, the uncertainty of social norms in early Soviet society became equated with an instability of environment in general and nature in particular. A powerful and vivid rhetoric of a "second nature," to use Gorky's phrase, overcame the absence of clearly articulated models for subjectivity. A series of disciplining routines and activities capable of producing the new Soviet subject compensated in the 1930s for the dissolution of the daily order of things and all the structuring effects, social networks, and reciprocal obligations that were associated with it. [source]

Regulation of signal transduction by glycosylation

INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2004
Robert S. Haltiwanger
The incredible diversity found in cell-surface glycoconjugate structures led researchers over 30 years ago to propose that complexity in carbohydrates must play a role in cellular communication. Recent studies from a number of laboratories have confirmed this hypothesis, demonstrating that cell-surface glycoconjugates play significant roles in signal transduction events. One striking example is the effect of O -fucose modifications on the Notch-signalling pathway. Notch is a cell-surface receptor that is essential for proper development. The extracellular domain of Notch contains up to 36-tandem epidermal growth factor-like (EGF) repeats, many of which are predicted to be modified at putative consensus sequences with O -fucose and O -glucose saccharides. Genetic alterations (by knockout or RNAi methodologies) in the enzyme responsible for the addition of O -fucose to Notch, protein O -fucosyltransferase-1, result in severe, embryonic lethal phenotypes resembling Notch mutants. Thus, O -fucosylation appears to be essential for proper Notch function. Elongation of the O -fucose monosaccharide by the ,1,3- N -acetylglucosaminyltransferase, Fringe, modulates Notch function, either increasing or decreasing response from ligands depending on context. Although it is now clear that O -fucose modifications affect Notch signalling, the molecular mechanism by which this occurs is not known. As an initial step in understanding how O -fucose glycans affect Notch function, we are mapping O -fucose modifications to specific sites on Notch. Already, we have demonstrated that O -fucose modifies one of the EGF repeats involved in ligand binding, suggesting that the sugars may play a role in Notch,ligand interactions. Experiments to test the role of O -fucose modifications at specific sites are in progress. We have also found that Fringe modifies O -fucose on some EGF repeats but not others. Our initial analyses suggest that the basis of this specificity is encoded within the sequences of the individual EGF repeats. Site mapping has also confirmed the presence of O -glucose saccharides on Notch. The evolutionarily conserved, predicted O -glucose sites on Notch are as numerous as those for O -fucose, suggesting that the O -glucose modifications will play an equally important role in Notch biology. We have recently identified an enzymatic activity capable of catalyzing the addition of O -glucose to EGF repeats. Purification of the protein O -glucosyltransferase is underway. These and other results will be discussed. [source]

Sinus Tissue Pharmacokinetics After Oral Administration of Amoxicillin/Clavulanic Acid

THE LARYNGOSCOPE, Issue 6 2000
Paulo Borges Dinis MD
Abstract Objectives The in vitro synergy of the amoxicillin/clavulanic acid combination has not always translated in vivo into clinical superiority compared with amoxicillin alone. Specifically, conflicting reports have disputed the superiority of the combination in the treatment of both acute otitis media and acute sinusitis. One possible reason for this may have to do with inadequate target tissue pharmacokinetics. To explore this possibility in the sinuses, we undertook the present investigation. Study Design A randomized, open, single-dose, sinus tissue pharmacokinetic study with oral amoxicillin/clavulanic acid. Methods Twenty-three adult patients with chronic rhinosinusitis who had been selected for surgery were randomly allocated to receive a tablet of 875/125 mg amo-icillin/clavulanate 2 to 4 hours before surgery began. During the operation tissue samples were collected at specific sinonasal sites for determination of both amo-icillin and clavulanic acid concentration levels. Results Amoxicillin displayed adequate tissue levels throughout the sinuses, high enough to cover common susceptible pathogens. However, the presence of clavulanate was detected in only half of the sinonasal tissue samples. Conclusions The kinetics of oral clavulanic acid apparently fails to provide a widespread anti,,-lactamase activity capable of enhancing the activity of amoxicillin in all parts of the sinuses. Despite this, amoxicillin/clavulanic acid maintains a central role in the treatment of acute rhinosinusitis, because amoxicillin is still the most effective oral ,-lactam against Streptococcus pneumoniae, a particularly virulent and increasingly resistant upper respiratory tract pathogen. Also, as our data show, a concomitant anti,,-lactamase activity can be expected to occur, although in an unpredictable fashion. [source]

Expression of a plant-derived peptide harboring water-cleaning and antimicrobial activities

BIOTECHNOLOGY & BIOENGINEERING, Issue 1 2003
M. Suarez
Abstract Drinking water is currently a scarce world resource, the preparation of which requires complex treatments that include clarification of suspended particles and disinfection. Seed extracts of Moringa oleifera Lam., a tropical tree, have been proposed as an environment-friendly alternative, due to their traditional use for the clarification of drinking water. However, the precise nature of the active components of the extract and whether they may be produced in recombinant form are unknown. Here we show that recombinant or synthetic forms of a cationic seed polypeptide mediate efficient sedimentation of suspended mineral particles and bacteria. Unexpectedly, the polypeptide was also found to possesses a bactericidal activity capable of disinfecting heavily contaminated water. Furthermore, the polypeptide has been shown to efficiently kill several pathogenic bacteria, including antibiotic-resistant isolates of Staphylococcus, Streptococcus, and Legionella species. Thus, this polypeptide displays the unprecedented feature of combining water purification and disinfectant properties. Identification of an active principle derived from the seed extracts points to a range of potential for drinking water treatment or skin and mucosal disinfection in clinical settings. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 13,20, 2003. [source]