Structure-activity optimization of inhibitory potency and duration of action of N-hydroxyurea containing 5-lipoxygenase inhibitors was conducted. The lipophilic heteroaryl template and the link group ...connecting the template to the N-hydroxyurea pharmacophore were modified. Inhibition of 5-lipoxygenase was evaluated in vitro in a human whole blood assay. An in vitro assay using liver microsomes from monkey was used to evaluate congeners for comparative rates of glucuronidation. (3-Heteroaryl-1-methyl-2-propynyl)-N-hydroxyureas were found to be more resistant to in vitro glucuronidation. The promising inhibitor N-3-5-(4-fluorophenoxy) 2-furyl-1-methyl-2-propynyl N-hydroxyurea (6) was found to have stereoselective glucuronidation in monkey and man. The R enantiomer 7 provided longer duration of inhibition as evaluated by an ex vivo whole blood assay. Further optimization of the lipophilic template led to the discovery of (R)-(+)-N-3-5-(4-fluorophenyl)methyl 2-thienyl-1-methyl 2-propynyl-N-hy droxyurea (11) with more effective and prolonged inhibition of leukotriene biosynthesis than zileuton (1) and 7 in monkey and man. The optimized 5-lipoxygenase inhibitor 11 was selected for development as an investigational drug for leukotriene-mediated disorders.
Recombinant-derived human interleukin-1 alpha (IL-1 alpha), purified from Escherichia coli, was resolved by isoelectric focusing on polyacrylamide gels into two species of isoelectric points (pI) ...5.45 and 5.20, which constituted approximately 75% and approximately 25% of the total IL-1 alpha protein respectively. The pI 5.45 and pI 5.20 species were separated by chromatofocusing and subjected to N-terminal sequence analysis. The pI 5.45 species contained the expected Asn residue at position 36 of the mature protein sequence whereas the pI 5.20 species contained an Asp residue at the same position. A mutant protein in which Asn-36 was substituted for a Ser residue was isolated from E. coli and shown to be homogeneous on isoelectric focusing analysis with a pI = 5.45. 1H-n.m.r. and circular dichroism analyses of wild-type and the mutant IL-1 alpha indicated a similar conformation which was also indicated by the identical receptor binding affinities of IL-1 alpha with Asn, Asp or Ser in position 36. The mutant protein was stabilized against specific base-catalysed and temperature-induced deamidation, and may be more suitable than the wild-type position for physical and structural studies.
The conformation and stability of recombinant‐derived human and murine granulocyte‐macrophage colony stimulating factors produced in Escherichia coli have been investigated by analytical ...ultracentrifugation, urea‐gradient polyacrylamide gel electrophoresis and several spectroscopic methods.
The proteins were demonstrated to be physically homogeneous monomeric proteins with compact globular shapes and shown to have similar secondary structures containing both α‐helix and β‐sheet structure.
The intramolecular disulphide linkages of both proteins were shown to be essential for maintaining native conformation as reduction with dithiothreitol resulted in protein unfolding.
Comparison of the human E. coli‐derived (non‐glycosylated) and mammalian cell culture‐derived (glyco‐sylated) proteins by urea‐gradient electrophoresis indicated that glycosylation had no major effect on the conformational stability and kinetics of urea induced unfolding and refolding.
An aminopeptidase specific for methionine (peptidase M) has been purified from wild‐type and mutant Salmonella typhimurium strains. Recombinant peptidase M was also purified from Escherichia coli. ...These preparations were characterized with respect to their physicochemical properties using analytical ultracentrifugation. SDS/PAGE, isoelectric focusing, titration curve analysis, amino acid analysis, N‐ and C‐terminal sequencing and various spectroscopic methods.
Peptidase M activity is stimulated by Co2+, in agreement with previous studies using crude extracts of Salmonella. The purified preparations did not contain significant amounts of any metal. Enzymically important metal is loosely associated and lost during enzyme purification.
Peptidase M was shown to contain seven free sulphydryl residues none of which are involved in either intraor inter‐molecular disulphide bonds. Most appear solvent‐accessible as evidenced by their reactivity under native conditions. Limited modification of the sulphydryl residues with either iodoacetamide or 5.5′‐dithiobis(2‐nitrobenzoic acid) led to inactivation. Several cysteines were shown to be labelled to various degrees by peptide mapping of inactivated S‐14Ccarboxymethylated protein. Whether cysteine modification affects enzymic activity directly (blocking an active site) or indirectly (by causing conformational change) remains to be established.
This article provides a partial test of the rational-technical model and of the patronage model of political mobility in the Soviet Communist Party. Two major hypotheses are examined: 1) the greater ...the number of patron client ties acquired by regional Party secretaries, the greater the probability of their upward mobility, and 2) the better the economic performance of the regions for which secretaries are responsible, the greater the probability of their upward mobility. Multiple regression analysis indicates only very weak support for these hypotheses for the 1955–1968 period in the RSFSR. Considerably greater support for the hypotheses is found when the following variables are controlled: level of economic development, political regime, and Party cohort. Changes in the level of policy conflict within the central elite are found to account for much of the variation over time in the explanatory power of the two models.
The HBR List: Breakthrough Ideas for 2006 Gardner, Howard; Williams, Dan; McDonough, William ...
Harvard business review,
02/2006, Letnik:
84, Številka:
2
Magazine Article
This article highlight 20 ideas bubbling up to the surface in 2006, including: 1. The ability to synthesize information will be the most valued trait for leaders. 2. Body area networks can lower ...health care costs and improve safety. 3. China is a seedbed for environmental innovation. 4. The next frontier for business will be managing incalculable uncertainty. 5. Business is confronting challenges as networks face off against networks. 6. Scientists are going beyond the lab and using the world outside as their petri dish. 7. Every newborn in America should receive $6,000 as a down payment on a productive life. 8. Customer-collaborators are starting to demand a stake in IP. 9. An OPEC-like organization to benefit consumers instead of producers is envisioned. 10. A model for peer-to-peer leadership development is described.
The intra-arterial blood pressure of 20 male patients with essential hypertension was continuously recorded during dynamic exercise. Graded exercise testing on a bicycle ergometer and a ...stair-climbing test were performed prior to and during treatment with oxprenolol. Acute oxprenolol therapy was associated with a reduction in heart rate but little reduction in blood pressure. Chronic treatment for 14.3 weeks with oxprenolol (mean daily dose, 344 mg) was associated with a substantial reduction of blood pressure at rest and at each level of bicycle exercise. A similar antihypertensive effect was demonstrated during stair climbing. The normal blood pressure response to exercise as assessed by the relative (percentage) increase in pressure above the pre-exercise level and the rate of increase in blood pressure (per unit of work), as well as exercise tolerance, were unchanged by chronic beta-blockade with oxprenolol.
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