Functionalization of α-hydroxyphosphonates as a convenient route to N-tosyl-α-aminophosphonates

Direct conversion of the α-hydroxyl group by para-toluenesulfonamide to yield α-(N-tosyl)aminophosphonates is reported. α-Aminophosphonates 23a,b–37a,b were obtained from the corresponding α-hydroxyphosphonates 6a,b–21a,b in the presence of K₂CO₃, via the retro-Abramov reaction of the appropriate aldehydes, 1–5. The subsequent formation of imines with simultaneous addition of diethyl phosphite provided access to the α-sulfonamide phosphonates 23a,b–37a,b with better diastereoselectivity than in the case of the Pudovik reaction. The mechanism for this transformation is proposed herein. When Cbz N-protected aziridine 9a,b and phenylalanine analogue 12a,b were exploited, intramolecular substitution was observed, leading to the corresponding epoxide 38 as the sole product, or oxazolidin-2-one 39 as a minor product. Analogous substitution was not observed in the case of proline 18a,b and serine 21a,b derivatives.

The reaction mechanism and diastereoselectivity of the direct transformation of α-hydroxyphosphonates 6a,b–21a,b by para-toluenesulfonamide, yielding α-(N-tosyl)aminophosphonates 23a,b–37a,b under K₂CO₃ conditions are presented.     

Rates of hospitalization among patients with deep vein thrombosis before and after the introduction of rivaroxaban

Background. Compared to warfarin, the non-vitamin K antagonist oral anticoagulant rivaroxaban may have advantages in treating patients with venous thromboembolism, because injectable bridging therapy and routine laboratory monitoring are not required. The objective of this study was to compare the rate of hospitalization in patients treated with rivaroxaban after its introduction with what it would have been before the introduction of rivaroxaban. Methods. A retrospective claims analysis was conducted using the MarketScan Hospital Drug Database from January 2011 to December 2013. Adult patients with a primary diagnosis of deep vein thrombosis (DVT) treated with rivaroxaban or low-molecular-weight heparin (LMWH) bridged to warfarin during the first day of an evaluation at a hospital were identified. Based on propensity-score methods, historical LMWH/warfarin patients (i.e., patients who received LMWH/warfarin before the approval of rivaroxaban) were matched 4:1 to rivaroxaban patients, and the rates of hospitalization were compared. Results. All rivaroxaban-treated patients (n = 134) in the database were well matched with four historical LMWH/warfarin-treated patients (n = 536). Among the rivaroxaban cohort, 60% of the patients were admitted to the hospital, compared to 82% of the historical patients treated with LMWH/warfarin in the matched cohort. The difference was statistically significant and corresponded to a 27% reduction in hospital admissions (rate ratio [95% confidence interval]: 0.73 [0.62–0.84]). Hospital admission rates adjusted for time-trend analyses also led to similar results. Conclusion. The availability of rivaroxaban significantly reduced the hospitalization rate in patients with DVT treated with rivaroxaban compared to what it would have been if only LMWH/warfarin were available.     

Screening for impaired liver function as a risk factor for drug safety at hospital admission of surgical patients

International Journal of Clinical Pharmacy - Background Hepatic insufficiency can affect patient safety and should therefore be considered during drug therapy. Hospital admission offers an ideal...     

Immunoregulation through membrane proteins modified by reducing conditions induced by immune reactions

Selected disulfide bonds in membrane proteins are labile and are thus susceptible to changes in redox potential and/or the presence of thiol isomerase enzymes. Modification of these disulfide bonds can lead to conformational changes of the protein that in turn may alter protein activity and function. This occurs in the entry of several enveloped viruses into their host cells, e.g. HIV, hepatitis C virus and Newcastle disease virus. Labile disulfide bonds are also important in platelet activation, cytokine signalling and in a variety of diseases including cancer and arthritis. In this review we will concentrate on recent advances in understanding the conditions that lead to disulfide bond reduction in membrane proteins and their effects in regulating immune function.     

Rapid and Reliable Identification of Staphylococcus aureus Capsular Serotypes by Means of Artificial Neural Network-Assisted Fourier Transform Infrared Spectroscopy

Staphylococcus aureus capsular polysaccharides (CP) are important virulence factors and represent putative targets for vaccine development. Therefore, the purpose of this study was to develop a high-throughput method to identify and discriminate the clinically important S. aureus capsular serotypes 5, 8, and NT (nontypeable). A comprehensive set of clinical isolates derived from different origins and control strains, representative for each serotype, were used to establish a CP typing system based on Fourier transform infrared (FTIR) spectroscopy and chemometric techniques. By combining FTIR spectroscopy with artificial neuronal network (ANN) analysis, a system was successfully established, allowing a rapid identification and discrimination of all three serotypes. The overall accuracy of the ANN-assisted FTIR spectroscopy CP typing system was 96.7% for the internal validation and 98.2% for the external validation. One isolate in the internal validation and one isolate in the external validation failed in the classification procedure, but none of the isolates was incorrectly classified. The present study demonstrates that ANN-assisted FTIR spectroscopy allows a rapid and reliable discrimination of S. aureus capsular serotypes. It is suitable for diagnostic as well as large-scale epidemiologic surveillance of S. aureus capsule expression and provides useful information with respect to chronicity of infection.