Design and synthesis of a bifunctional label for selection of beta-lactamase displayed on filamentous bacteriophage by catalytic activity

A bifunctional activity label 1c has been constructed for the selection of active beta-lactamases displayed on filamentous bacteriophage. It features an original 6-sulfonylamido-penam sulfone moiety, as beta-lactamase suicide-inhibitor, and a biotinyl residue, for separation by affinity chromatography, connected through a linker including a cleavable disulfide bond. The inhibitor 28 resulted from coupling of methoxymethyl 6-aminopenicillinate 8 with N-protected (aminoethoxy)ethoxyethanesulfonyl chloride 23, followed by oxidation into the corresponding sulfone 25, and usual deprotections. The biotinyl ester 32 reacted with 3-(2-aminoethyldithio)propanoic acid 31 as linker, to give 33 which was further activated as pentafluorophenol ester 34b. Final coupling of the building blocks 28 and 34b gave the target label 1c. Copyright (C) 1996 Elsevier Science Lt

Synthesis, reactivity and biochemical evaluation of 1,3-substituted azetidin-2-ones as enzyme inhibitors

A series of monocyclic azetidinones were prepared, bearing, at position C-3, an acetylamino or a bromo substituent, at position N-1, a carboxymethyl group protected as p-nitrobenzyl ester (PNB) and alpha-functionalized with a potential leaving group (LG). These structures were designed as potential suicide-inhibitors of enzymes containing a serine nucleophile in their active site. The beta-lactam ring of these molecules was found to be stable in phosphate buffer (pH 7.5), but the PNB ester was rapidly cleaved. This constitutes a practical method of in situ deprotection. Depending on the nature of the LG group on the carboxymethyl chain, substitution of this group (LG = F) or decarboxylation (LG = SO2Ph) was observed under hydrolytic conditions. The 1,3-disubstituted azetidinones were inactive against beta-lactamases of classes A, B, C, and D. Three compounds behaved as weak reversible inhibitors of porcine pancreatic elastase (PPE). (C) 1999 Elsevier Science Ltd. All rights reserved

1-alkoxycarbonyl-3-bromoazetidin-2-ones as potential elastase inhibitors

Three 1-alkoxycarbonyl-3-bromoazetidin-2-ones have been prepared by reaction of (3S)-3-(tert-butoxycarbonyl) amino azetidin-2-one with benzyl, trichloroethyl, and trifluoroethyl chloroformates followed by tBoc deprotection, diazotation of the exocyclic amino function and its substitution with potassium bromide. The 3-bromoazetidin-2-ones were obtained as racemic mixtures. Their hydroxide-catalyzed hydrolysis exclusively affords ring-opening products. Porcine pancreatic elastase (PPE) catalyzes the same reaction stereospecifically. Model building suggests that it is the (R) isomer that is enzymatically hydrolysed, The PPE-catalyzed hydrolysis is characterised by low k(cat) and K-m values. Accordingly, these compounds behave as transient inhibitors of the enzyme

Intensive care unit acquired infection and organ failure

OBJECTIVE: To assess the temporal relationship between ICU-acquired infection (IAI) and the prevalence and severity of organ dysfunction or failure (OD/F). DESIGN AND SETTING: Observational, single center study in a mixed intensive care unit of a university hospital. PATIENTS: We analyzed 1,191 patients hospitalized for more than 2 days during a 2-year observation period: 845 did not acquire IAI, 306 of whom had infection on admission (IOA); 346 did acquire IAI, 125 of whom had IOA. MEASUREMENTS AND RESULTS: The SOFA score was calculated daily, both SOFAmax, the sum of the worst OD/F during the ICU stay, and SOFApreinf, the sum of the worst OD/F existing before the occurrence of the first IAI. The SAPS II and SOFA score of the first 24 h were significantly higher in patients with than in those without IAI. SOFApreinf of IAI patients was also higher than the SOFAmax of patients without IAI both in patients with (12.1+/-4.6 vs. 8.9+/-4.7) and those without IOA (9.2+/-4.0 vs. 6.7+/-3.5). SOFApreinf represented 85.7% of the value of SOFAmax in patients with IAI. SOFApreinf increased significantly with the occurrence of sepsis, severe sepsis, or septic shock during ICU stay. Severe sepsis and septic shock during ICU stay as well as SOFApreinf were part of the factors associated with hospital mortality. CONCLUSIONS: IAI is significantly associated with hospital mortality; however, its contribution to OD/F is minor. Moreover, severity of IAI seems to be related to previous health status

Sedation in the Neonatal Intensive Care Unit: International Practice

Inadequate pain management in neonatal life impairs neurodevelopmental outcome because it alters pain thresholds, pain- or stress-related behavior, and physiological responses later in life. However, there are recently also emerging animal experimental and human epidemiological data on the impact of analgo-sedatives on neuro-apoptosis and impaired neurodevelopmental outcome. As a consequence, the management of neonatal pain is in search of a new balance, and these conflicting observations are the main drivers to tailor our pain management in neonates. Adequate pain management is based on prevention, assessment, and treatment with subsequent reassessment. Issues related to prevention and assessment tools are covered. Non-pharmacological (e.g., complementary interventions like facilitated tucking, nonnutritive sucking) and pharmacological (e.g., acetaminophen, opioids, ketamine, propofol) treatment modalities were reviewed and reflect the increased knowledge on neonatal pain management. Each topic ends with some take-home messages that in part also reflect our opinion on the current status of this topic.</p