Trypanothione reductase (TR) is both a valid and an attractive target for the design of new trypanocidal drugs. Starting from menadione, plumbagin, and juglone, three distinct series of 1,4-naphthoquinones (NQ) were synthesized as potential inhibitors of TR from Trypanosoma cruzi (TcTR). The three parent molecules were functionalized at carbons 2 and/or 3 by various polyamine chains. Optimization of TcTR inhibition and TcTR specificity versus human disulfide reductases was achieved with the 3,3'-[polyaminobis(carbonylalkyl)]bis(1,4-NQ) series 19-20, in which an optimum chain length was determined for inhibition of the trypanothione disulfide reduction. The most active derivatives against trypanosomes in cultures were also studied as subversive substrates of TcTR and lipoamide dehydrogenase (TcLipDH). The activities were measured by following NAD(P)H oxidation as well as coupling the reactions to the reduction of cytochrome c which permits the detection of one-electron transfer. For TcTR, 20(4-c) proved to be a potent subversive substrate and an effective uncompetitive inhibitor versus trypanothione disulfide and NADPH. Molecular modeling studies based on the known X-ray structures of TcTR and hGR were conducted in order to compare the structural features, dimensions, and accessibility of the cavity at the dimer interface of TcTR with that of hGR, as one of the putative NQ binding sites. TcLipDH reduced the plumbagin derivatives by an order of magnitude faster than the corresponding menadione derivatives. Such differences were not observed with the pig heart enzyme. The most efficient and specific subversive substrates of TcTR and TcLipDH exhibited potent antitrypanosomal activity in in vitro T. brucei and T. cruzi cultures. The results obtained here confirm that reduction of NQs by parasitic flavoenzymes is a promising strategy for the development of new trypanocidal drugs.

IntroductionWe characterized the safety and tolerability of empagliflozin in patients with type 2 diabetes (T2DM) randomized 1:1:1 to placebo, empagliflozin 10 mg, or empagliflozin 25 mg in clinical trials.MethodsPooled data were analyzed from patients with T2DM treated with placebo (N = 4203), empagliflozin 10 mg (N = 4221), or empagliflozin 25 mg (N = 4196) in 15 randomized phase I–III trials plus four extension studies. Adverse events (AEs) were assessed descriptively in participants who took at least one dose of study drug. AE incidence rates per 100 patient-years were calculated to adjust for differences in drug exposure between trials.ResultsTotal exposure was 7369, 7782, and 7754 patient-years in the placebo, empagliflozin 10 mg, and 25 mg groups, respectively. The incidence of any AEs, severe AEs, serious AEs, and AEs leading to discontinuation was no higher in participants treated with empagliflozin vs. placebo. Empagliflozin was not associated with an increased risk of hypoglycemia vs. placebo, except in participants on background sulfonylurea. The incidence of events consistent with urinary tract infection was similar across treatment groups (8.7–9.5/100 patient-years). Events consistent with genital infection occurred more frequently in participants treated with empagliflozin 10 and 25 mg (3.5 and 3.4/100 patient-years, respectively) than placebo (0.9/100 patient-years). The incidence of AEs consistent with volume depletion was similar across treatment groups (1.7–1.9/100 patient-years) but was higher with empagliflozin 10 mg and 25 mg vs. placebo in participants aged 75 years or older (3.2 and 3.0 vs. 2.3/100 patient-years, respectively). The rates of bone fractures, cancer events, renal AEs, venous thromboembolic events, hepatic injury, acute pancreatitis, lower limb amputations, and diabetic ketoacidosis were similar across treatment groups.ConclusionThis analysis of pooled safety data based on more than 15,000 patient-years’ exposure supports a favorable benefit–risk profile of empagliflozin in patients with T2DM.FundingBoehringer Ingelheim Pharma GmbH.Electronic supplementary materialThe online version of this article (doi:10.1007/s12325-017-0573-0) contains supplementary material, which is available to authorized users.

OH/OD product state distributions arising from the reaction of gas-phase O(3P) atoms at the surface of the liquid hydrocarbon squalane C30H62/C30D62 have been measured. The O(3P) atoms were generated by 355 nm laser photolysis of NO2 at a low pressure above the continually refreshed liquid. It has been shown unambiguously that the hydroxyl radicals detected by laser-induced fluorescence originate from the squalane surface. The gas-phase OH/OD rotational populations are found to be partially sensitive to the liquid temperature, but do not adapt to it completely. In addition, rotational temperatures for OH/OD(v'=1) are consistently colder (by 34+/-5 K) than those for OH/OD(v'=0). This is reminiscent of, but less pronounced than, a similar effect in the well-studied homogeneous gas-phase reaction of O(3P) with smaller hydrocarbons. We conclude that the rotational distributions are composed of two different components. One originates from a direct abstraction mechanism with product characteristics similar to those in the gas phase. The other is a trapping-desorption process yielding a thermal, Boltzmann-like distribution close to the surface temperature. This conclusion is consistent with that reached previously from independent measurements of OH product velocity distributions in complementary molecular-beam scattering experiments. It is further supported by the temporal profiles of OH/OD laser-induced fluorescence signals as a function of distance from the surface observed in the current experiments. The vibrational branching ratios for (v'=1)/(v'=0) for OH and OD have been found to be (0.07+/-0.02) and (0.30+/-0.10), respectively. The detection of vibrationally excited hydroxyl radicals suggests that secondary and/or tertiary hydrogen atoms may be accessible to the attacking oxygen atoms.

Our present study verifies the protective effect of methylprednisolone treatment in deceased donor liver transplantation, suggesting it as a potential therapeutical approach.

We report the first measurements of internal energy distributions of the OH produced via a direct mechanism, isolated from other components on the basis of time-of-flight, in the interfacial reaction between gas-phase O((3)P) atoms and the liquid hydrocarbon squalane, C(30)H(62). O((3)P) atoms were generated by laser photolysis of NO(2) above the liquid. Resulting hydroxyl radicals that escape from the surface were detected by laser-induced fluorescence. Time-of-flight profiles demonstrate that the kinetic energy of the fastest OH (nu' = 1) is lower than that of (nu' = 0). Rotational distributions were measured at the rising edge of their appearance for both OH (nu' = 0) and (nu' = 1). They were found to differ substantially more than at the peak of their profiles. They were also less dependent on the bulk liquid temperature. We conclude that the new data confirm strongly that at least two mechanisms contribute to the production of OH. The higher-velocity component has translational and rotational energy distributions, observed cleanly for the first time, consistent with a direct mechanism. The close correspondence of these rotational distributions to those from the corresponding homogeneous gas-phase reaction of O((3)P) with smaller hydrocarbons suggests a very similar, near collinear direct abstraction. This is accompanied by a slower component with kinetic energy and rotational (but not vibrational) distributions reflecting the temperature of the liquid, consistent with a distinct trapping-desorption mechanism.

We describe an experimental approach to the determination of the nascent internal state distribution of gas-phase products of a gas–liquid interfacial reaction. The system chosen for study is O(3P) atoms with the surface of liquid deuterated squalane, a partially branched long-chain saturated hydrocarbon, C30D62. The nascent OD products are detected by laser-induced fluorescence. Both OD (v′=0) and (v′=1) were observed in significant yield. The rotational distributions in both vibrational levels are essentially the same, and are characteristic of a Boltzmann distribution at a temperature close to that of the liquid surface. This contrasts with the distributions in the corresponding homogeneous gas-phase reactions. We propose a preliminary interpretation in terms of a dominant trapping-desorption mechanism, in which the OD molecules are retained at the surface sufficiently long to cause rotational equilibration but not complete vibrational relaxation. The significant yield of vibrationally excited OD also suggests that the surface is not composed entirely of –CD3 endgroups, but that secondary and/or tertiary units along the backbone are exposed.

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The kinetics of the reactions of OH radicals with propene and isoprene in N 2 have been studied in the temperature range of 58-300 K in a Laval nozzle expansion. Laser-induced fluorescence of the OH radical that is formed in the photolysis of H 2 O 2 at 193 nm has been detected. The determined rate constants (2 × 10 -11 to 2 × 10 -10 cm 3 molecule -1 s -1 ) for the OH radicals reacting with excess propene and isoprene (2methyl-1,3-butadiene) have been found to increase when the temperature is decreased. The room temperature rate constants are in agreement with the literature data. Below 120 K, a saturation of the rate constant for the case of propene and a turnover to a formally positive temperature dependence for isoprene have been observed. The observed negative temperature dependence and the course of the temperature dependence at very low temperatures for both reactions are discussed within the framework of the loose transition-state theory and a simple two-transition-state model.