Imitation of β-lactam binding enables broad-spectrum metallo-β-lactamase inhibitors

Carbapenems are vital antibiotics, but their efficacy is increasingly compromised by metallo-beta-lactamases (MBLs). Here we report the discovery and optimization of potent broad-spectrum MBL inhibitors. A high-throughput screen for NDM-1 inhibitors identified indole-2-carboxylates (InCs) as potential beta-lactamase stable beta-lactam mimics. Subsequent structure-activity relationship studies revealed InCs as a new class of potent MBL inhibitor, active against all MBL classes of major clinical relevance. Crystallographic studies revealed a binding mode of the InCs to MBLs that, in some regards, mimics that predicted for intact carbapenems, including with respect to maintenance of the Zn(II)-bound hydroxyl, and in other regards mimics binding observed in MBL-carbapenem product complexes. InCs restore carbapenem activity against multiple drug-resistant Gram-negative bacteria and have a low frequency of resistance. InCs also have a good in vivo safety profile, and when combined with meropenem show a strong in vivo efficacy in peritonitis and thigh mouse infection models.Peer reviewe

Design and Synthesis of Hepatitis C Virus NS3 Protease Inhibitors : Targeting Different Genotypes and Drug-Resistant Variants

Since the first approved hepatitis C virus (HCV) NS3 protease inhibitors in 2011, numerous direct acting antivirals (DAAs) have reached late stages of clinical trials. Today, several combination therapies, based on different DAAs, with or without the need of pegylated interferon-α injection, are available for chronic HCV infections. The chemical foundation of the approved and late-stage HCV NS3 protease inhibitors is markedly similar. This could partly explain the cross-resistance that have emerged under the pressure of NS3 protease inhibitors. The first-generation NS3 protease inhibitors were developed to efficiently inhibit genotype 1 of the virus and were less potent against other genotypes. The main focus in this thesis was to design and synthesize a new class of 2(1H)-pyrazinone based HCV NS3 protease inhibitors, structurally dissimilar to the inhibitors evaluated in clinical trials or approved, potentially with a unique resistance profile and with a broad genotypic coverage. Successive modifications were performed around the pyrazinone core structure to clarify the structure-activity relationship; a P3 urea capping group was found valuable for inhibitory potency, as were elongated R6 residues possibly directed towards the S2 pocket. Dissimilar to previously developed inhibitors, the P1’ aryl acyl sulfonamide was not essential for inhibition as shown by equally good inhibitory potency for P1’ truncated inhibitors. In vitro pharmacokinetic (PK) evaluations disclosed a marked influence from the R6 moiety on the overall drug-properties and biochemical evaluation of the inhibitors against drug resistant enzyme variants showed retained inhibitory potency as compared to the wild-type enzyme. Initial evaluation against genotype 3a displayed micro-molar potencies. Lead optimization, with respect to improved PK properties, were also performed on an advanced class of HCV NS3 protease inhibitors, containing a P2 quinazoline substituent in combination with a macro-cyclic proline urea scaffold with nano-molar cell based activities. Moreover, an efficient Pd-catalyzed C-N urea arylation protocol, enabling high yielding introductions of advanced urea substituents to the C3 position of the pyrazinone, and a Pd-catalyzed carbonylation procedure, to obtain acyl sulfinamides, were developed. These methods can be generally applicable in the synthesis of bioactive compounds containing peptidomimetic scaffolds and carboxylic acid bioisosteres

Factors influencing doctors' counselling on patients' lifestyle habits: a cohort study

Background Lifestyle changes are important for prevention and treatment of many common diseases, and doctors have an important role in the lifestyle counselling of patients. It is important to know more about factors influencing lifestyle counselling. Aim To investigate the frequency of counselling about physical activity compared to that about alcohol habits; the impact of doctors’ own physical activity and alcohol habits on patient counselling about these lifestyle dimensions; and whether perceived mastery of clinical work or vulnerable personality have a confounding or moderating effect on these associations. Design & setting In this nationwide cohort survey, a total of 978 doctors in Norway were surveyed by postal questionnaires in 1993/94 and 2014. The response rate was 562/978 (57%). Method The outcome variables were questions on frequency of asking about alcohol and exercise habits. Explanatory variables were questions on doctors’ own exercise habits, drinking habits (using Alcohol Use Disorders Identification Test [AUDIT]), perceived mastery of clinical work, vulnerable personality, and specialty. Associations were studied by linear regression analysis. Results Of the 526 responders, 307 (58%) reported asking usually/often about exercise habits, while n = 140/524 (27%) usually/often asked about alcohol habits. A doctor's own physical activity level was associated with frequency of asking about physical activity (unstandardised regression coefficient [B] = 0.07; 95% confidence intervals [CI] = 0.01 to 0.13). There were no significant associations between doctors' own lifestyle habits and counselling on alcohol habits. Doctors with low levels of vulnerability asked more frequently about physical activity, regardless of their own physical activity habits (F = 2.41, P = 0.048). Conclusion Doctors’ own lifestyles influenced their preventive counselling about physical activity, but not about alcohol. Vulnerability moderated these effects, indicating the importance of early interventions to help doctors with a vulnerable personality to handle negative criticism from patient

A dose based approach for evaluation of inter-observer variations in target delineation

Background and purpose: Substantial inter-observer variations in target delineation have been presented previously. Target delineation for paediatric cases is difficult due to the small number of children, the variation in paediatric targets, the number of study protocols, and the individual patient's specific needs and demands. Uncertainties in target delineation might lead to under-dosage or over-dosage. The aim of this work is to apply the concept of a consensus volume and good quality treatment plans to visualise and quantify inter-observer target delineation variations in dosimetric terms in addition to conventional geometrically based volume concordance indices.Material and methods: Two paediatric cases were used to demonstrate the potential of adding dose metrics when evaluating target delineation diversity; Hodgkin's disease (case 1) and rhabdomyosarcoma of the parotid gland (case 2). The variability in target delineation (PTV delineations) between six centres was quantified using the generalised conformity index, CIgen, generated for volume overlap. The STAPLE algorithm, as implemented in CERR, was used for both cases to derive a consensus volumes. STAPLE is a probabilistic estimate of the true volume generated from all observers. Dose distributions created by each centre for the original target volumes were then applied to this consensus volume.Results: A considerable variation in target segmentation was seen in both cases. For case 1 the variation was 374-960 cm3 (average 669 cm3) and for case 2; 65-126 cm3 (average 109 cm3). CIgen were 0.53 and 0.70, respectively. The DVHs in absolute volume displayed for the delineated target volume as well as for the consensus volume adds information on both "compliant" target volumes as well as outliers which are hidden with just the use of concordance indices.Conclusions: The DVHs in absolute volume add valuable and easily understood information to various indices for evaluating uniformity in target delineation

Factors influencing doctors' counselling on patients' lifestyle habits: a cohort study

Background Lifestyle changes are important for prevention and treatment of many common diseases, and doctors have an important role in the lifestyle counselling of patients. It is important to know more about factors influencing lifestyle counselling. Aim To investigate the frequency of counselling about physical activity compared to that about alcohol habits; the impact of doctors’ own physical activity and alcohol habits on patient counselling about these lifestyle dimensions; and whether perceived mastery of clinical work or vulnerable personality have a confounding or moderating effect on these associations. Design & setting In this nationwide cohort survey, a total of 978 doctors in Norway were surveyed by postal questionnaires in 1993/94 and 2014. The response rate was 562/978 (57%). Method The outcome variables were questions on frequency of asking about alcohol and exercise habits. Explanatory variables were questions on doctors’ own exercise habits, drinking habits (using Alcohol Use Disorders Identification Test [AUDIT]), perceived mastery of clinical work, vulnerable personality, and specialty. Associations were studied by linear regression analysis. Results Of the 526 responders, 307 (58%) reported asking usually/often about exercise habits, while n = 140/524 (27%) usually/often asked about alcohol habits. A doctor's own physical activity level was associated with frequency of asking about physical activity (unstandardised regression coefficient [B] = 0.07; 95% confidence intervals [CI] = 0.01 to 0.13). There were no significant associations between doctors' own lifestyle habits and counselling on alcohol habits. Doctors with low levels of vulnerability asked more frequently about physical activity, regardless of their own physical activity habits (F = 2.41, P = 0.048). Conclusion Doctors’ own lifestyles influenced their preventive counselling about physical activity, but not about alcohol. Vulnerability moderated these effects, indicating the importance of early interventions to help doctors with a vulnerable personality to handle negative criticism from patient

Factors influencing doctors' counselling on patients' lifestyle habits: a cohort study

Background Lifestyle changes are important for prevention and treatment of many common diseases, and doctors have an important role in the lifestyle counselling of patients. It is important to know more about factors influencing lifestyle counselling. Aim To investigate the frequency of counselling about physical activity compared to that about alcohol habits; the impact of doctors’ own physical activity and alcohol habits on patient counselling about these lifestyle dimensions; and whether perceived mastery of clinical work or vulnerable personality have a confounding or moderating effect on these associations. Design & setting In this nationwide cohort survey, a total of 978 doctors in Norway were surveyed by postal questionnaires in 1993/94 and 2014. The response rate was 562/978 (57%). Method The outcome variables were questions on frequency of asking about alcohol and exercise habits. Explanatory variables were questions on doctors’ own exercise habits, drinking habits (using Alcohol Use Disorders Identification Test [AUDIT]), perceived mastery of clinical work, vulnerable personality, and specialty. Associations were studied by linear regression analysis. Results Of the 526 responders, 307 (58%) reported asking usually/often about exercise habits, while n = 140/524 (27%) usually/often asked about alcohol habits. A doctor's own physical activity level was associated with frequency of asking about physical activity (unstandardised regression coefficient [B] = 0.07; 95% confidence intervals [CI] = 0.01 to 0.13). There were no significant associations between doctors' own lifestyle habits and counselling on alcohol habits. Doctors with low levels of vulnerability asked more frequently about physical activity, regardless of their own physical activity habits (F = 2.41, P = 0.048). Conclusion Doctors’ own lifestyles influenced their preventive counselling about physical activity, but not about alcohol. Vulnerability moderated these effects, indicating the importance of early interventions to help doctors with a vulnerable personality to handle negative criticism from patientsFactors influencing doctors' counselling on patients' lifestyle habits: a cohort studypublishedVersio

Pan-NS3 protease inhibitors of hepatitis C virus based on an R-elongated pyrazinone scaffold

Herein, we present the design and synthesis of 2(1H)-pyrazinone based HCV NS3 protease inhibitors and show that elongated Rurea substituents were associated with increased inhibitory potencies over several NS3 protein variants. The inhibitors are believed to rely on β-sheet mimicking hydrogen bonds which are similar over different genotypes and current drug resistant variants and correspond to the β-sheet interactions of the natural peptide substrate. Inhibitor 36, for example, with a urea substituent including a cyclic imide showed balanced nanomolar inhibitory potencies against genotype 1a, both wild-type (K = 30 nM) and R155K (K = 2 nM), and genotype 3a (K = 5 nM).status: publishe

Design and synthesis of potent inhibitors of the malaria aspartyl proteases plasmepsin I and II. Use of solid-phase synthesis to explore novel statine motifs.

Picomolar to low nanomolar inhibitors of the two aspartic proteases plasmepsin (Plm) I and II, from the malaria parasite Plasmodium falciparum, have been identified from sets of libraries containing novel statine-like templates modified at the amino and carboxy terminus. The syntheses of the novel statine templates were carried out in solution phase using efficient synthetic routes and resulting in excellent stereochemical control. The most promising statine template was attached to solid support and diversified by use of parallel synthesis. The products were evaluated for their Plm I and II inhibitory activity as well as their selectivity over cathepsin D. Selected inhibitors were, in addition, evaluated for their inhibition of parasite growth in cultured infected human red blood cells. The most potent inhibitor in this report, compound 16, displays Ki values of 0.5 and 2.2 nM for Plm I and II, respectively. Inhibitor 16 is also effective in attenuating parasite growth in red blood cells showing 51% inhibition at a concentration of 5 microM. Several inhibitors have been identified that exhibit Ki values between 0.5 and 74 nM for both Plm I and II. Some of these inhibitors also show excellent selectivity vs cathepsin D

Achiral Pyrazinone-Based Inhibitors of the Hepatitis C Virus NS3 Protease and Drug-Resistant Variants with Elongated Substituents Directed Toward the S2 Pocket

Herein we describe the design, synthesis, inhibitory potency, and pharmacokinetic properties of a novel class of achiral peptidomimetic HCV NS3 protease inhibitors. The compounds are based on a dipeptidomimetic pyrazinone glycine P3P2 building block in combination with an aromatic acyl sulfonamide in the P1P1′ position. Structure–activity relationship data and molecular modeling support occupancy of the S2 pocket from elongated R⁶ substituents on the 2­(1<i>H</i>)-pyrazinone core and several inhibitors with improved inhibitory potency down to <i>K</i>_i = 0.11 μM were identified. A major goal with the design was to produce inhibitors structurally dissimilar to the di- and tripeptide-based HCV protease inhibitors in advanced stages of development for which cross-resistance might be an issue. Therefore, the retained and improved inhibitory potency against the drug-resistant variants A156T, D168V, and R155K further strengthen the potential of this class of inhibitors. A number of the inhibitors were tested in in vitro preclinical profiling assays to evaluate their apparent pharmacokinetic properties. The various R⁶ substituents were found to have a major influence on solubility, metabolic stability, and cell permeability