Bending the Curve of Global Freshwater Biodiversity Loss: An Emergency Recovery Plan.

Despite their limited spatial extent, freshwater ecosystems host remarkable biodiversity, including one-third of all vertebrate species. This biodiversity is declining dramatically: Globally, wetlands are vanishing three times faster than forests, and freshwater vertebrate populations have fallen more than twice as steeply as terrestrial or marine populations. Threats to freshwater biodiversity are well documented but coordinated action to reverse the decline is lacking. We present an Emergency Recovery Plan to bend the curve of freshwater biodiversity loss. Priority actions include accelerating implementation of environmental flows; improving water quality; protecting and restoring critical habitats; managing the exploitation of freshwater ecosystem resources, especially species and riverine aggregates; preventing and controlling nonnative species invasions; and safeguarding and restoring river connectivity. We recommend adjustments to targets and indicators for the Convention on Biological Diversity and the Sustainable Development Goals and roles for national and international state and nonstate actors.

Provider volume and maternal complications after Caesarean section: results from a population-based study.

BACKGROUND: A large literature search suggests a relationship between hospital/surgeon caseload volume and surgical complications. In this study, we describe associations between post-operative maternal complications following Caesarean section and provider caseload volume, provider years since graduation, and provider specialization, while adjusting for hospital volumes and patient characteristics. METHODS: Our analysis is based on population-based discharge abstract data for the period of April 2004 to March 2014, linked to patient and physician universal coverage registry data. We consider all hospital admissions (N = 20,914) in New Brunswick, Canada, where a Caesarean Section surgery was recorded, as identified by a Canadian Classification of Health Intervention code of 5.MD.60.XX. We ran logistic regression models to identify the odds of occurrence of post-surgical complications during the hospital stay. RESULTS: Roughly 2.6% of admissions had at least one of the following groups of complications: disseminated intravascular coagulation, postpartum sepsis, postpartum hemorrhage, and postpartum infection. The likelihood of complication was negatively associated with provider volume and provider years of experience, and positively associated with having a specialization other than maternal-fetal medicine or obstetrics and gynecology. CONCLUSIONS: Our results suggest that measures of physician training and experience are associated with the likelihood of Caesarean Section complications. In the context of a rural province deciding on the number of rural hospitals to keep open, this suggests a trade off between the benefits of increased volume versus the increased travel time for patients.

Provider caseload volume and short-term outcomes following colorectal surgeries in New Brunswick: a provincial-level cohort study.

BACKGROUND: American studies have shown that higher provider and hospital volumes are associated with reduced risk of mortality following colorectal surgical interventions. Evidence from Canada is limited, and to our knowledge only a single study has considered outcomes other than death. We describe associations between provider surgical volume and all-cause mortality and postoperative complications following colorectal surgical interventions in New Brunswick. METHODS: We used hospital discharge abstracts linked to vital statistics, the provincial cancer registry and patient registry data. We considered all admissions for colorectal surgeries from 2007 through 2013. We used logistic regression to identify odds of dying and odds of complications (from any of anastomosis leak, unplanned colostomy, intra-abdominal sepsis or pneumonia) within 30 days of discharge from hospital according to provider volume (i.e., total interventions performed over the preceding 2 years) adjusted for personal, contextual, provider and hospital characteristics. RESULTS: Overall, 9170 interventions were performed by 125 providers across 18 hospitals. We found decreased odds of experiencing a complication following colorectal surgery per increment of 10 interventions performed per year (odds ratio 0.94, 95% confidence interval 0.91-0.96). We found no associations with mortality. Associations remained consistent across models restricted to cancer patients or to interventions performed by general surgeons and across models that also considered overall hospital volumes. CONCLUSION: Our results suggest that increased caseloads are associated with reduced odds of complications, but not with all-cause mortality, following colorectal surgery in New Brunswick. We also found no evidence of volume having differential effects on outcomes from colon and rectal procedures.

CONTEXTE: Des études américaines ont montré que le volume d'activité des chirurgiens et des hôpitaux est inversement proportionnel au risque de mortalité après la chirurgie colorectale. Les données pour le Canada sont limitées, et à notre connaissance, une seule étude a porté sur d'autres paramètres que le décès. Nous avons décrit les liens entre volume d'activité des chirurgiens et mortalité de toute cause/complications postopératoires après la chirurgie colorectale au Nouveau-Brunswick. MÉTHODES: Nous avons utilisé les registres de congés des hôpitaux reliés aux données de la Statistique de l'état civil, du registre provincial du cancer et du registre des patients. Nous avons recensé toutes les admissions pour chirurgie colorectale de 2007 à 2013. Nous avons utilisé la régression logistique pour établir le risque de décès et le risque de complications (fuite anastomotique, colostomie non planifiée, infection intra-abdominale ou pneumonie) dans les 30 jours suivant le congé de l'hôpital par rapport au volume d'activité des chirurgiens (c.-à-d., interventions totales des 2 années précédentes) ajusté en fonction des caractéristiques individuelles et contextuelles, propres aux chirurgiens et aux hôpitaux. RÉSULTATS: En tout, 125 chirurgiens ont effectué 9170 interventions dans 18 hôpitaux. Nous avons observé un risque moindre de complications après la chirurgie colorectale pour chaque palier de 10 interventions effectuées annuellement (risque relatif 0,94, intervalle de confiance de 95 %, 0,91­0,96). Nous n'avons observé aucun lien avec la mortalité. Les liens sont demeurés constants, peu importe que les modèles soient restreints aux patients cancéreux ou aux interventions effectuées par des chirurgiens généraux et entre les modèles qui tenaient également compte du volume global d'activité des hôpitaux. CONCLUSION: Selon nos résultats, l'augmentation du volume d'activité est associée à un risque moindre de complications, mais n'a pas de lien avec la mortalité de toute cause après la chirurgie colorectale au Nouveau-Brunswick. Nous n'avons pas non plus constaté de lien entre le volume d'activité et l'issue différentielle de la chirurgie du côlon et du rectum.

Associations between provider and hospital volumes and postoperative mortality following total hip arthroplasty in New Brunswick: results from a provincial-level cohort study.

BACKGROUND: Several international studies have reported negative associations between hospital and/or provider volume and risk of postoperative death following total hip arthroplasty (THA). The only Canadian studies to report on this have been based in Ontario and have found no such association. We describe associations between postoperative deaths following THA and provider caseload volume, also adjusted for hospital volume, in a population-based cohort in New Brunswick. METHODS: Our analyses are based on hospital discharge abstract data linked to vital statistics and to patient registry data. We considered all first known admissions for THA in New Brunswick between Jan. 1, 2007, and Dec. 31, 2013. Provider volume was defined as total THAs performed over the preceding 2 years. We fit logistic regression models to identify odds of dying within 30 and 90 days according to provider caseload volume adjusted for selected personal and contextual characteristics. RESULTS: About 7095 patients were admitted for THA in New Brunswick over the 7-year study period and 170 died within 30 days. We found no associations with provider volume and postoperative mortality in any of our models. Adjustment for contextual characteristics or hospital volume had no effects on this association. CONCLUSION: Our results suggest that patients admitted for hip replacements in New Brunswick can expect to have similar risk of death regardless of whether they are admitted to see a provider with high or low THA volumes and of whether they are admitted to the province's larger or smaller hospitals.

CONTEXTE: Plusieurs études internationales rapportent un lien négatif entre le volume d'activité de l'hôpital ou du fournisseur de soins de santé et le risque de décès postopératoire lié à une arthroplastie totale de la hanche. Les seules études canadiennes qui se sont intéressées à cette question ont été réalisées en Ontario et n'ont pas rapporté ce lien. Dans notre étude, nous tentons de décrire des liens entre le décès postopératoire lié à une arthroplastie totale de la hanche et le volume de la charge de travail du fournisseur de soins de santé, également ajustés pour tenir compte du volume d'activité de l'hôpital, au sein d'une cohorte basée sur la population au Nouveau-Brunswick. MÉTHODES: Nos analyses reposent sur les données portant sur les congés des hôpitaux, associées aux statistiques de l'état civil et aux données des registres des patients. Nous avons examiné toutes les premières hospitalisations connues en vue d'une arthroplastie totale de la hanche au Nouveau-Brunswick entre le 1er janvier 2007 et le 31 décembre 2013. Le volume d'activité du fournisseur de soins de santé a été défini comme étant la totalité des arthroplasties totales de la hanche pratiquées au cours des 2 années précédentes. Nous avons ajusté les modèles de régression logistique de manière à identifier le risque de décès dans les 30 et 90 jours en fonction du volume de la charge de travail du fournisseur de soins de santé, pour tenir compte de caractéristiques personnelles et contextuelles choisies. RÉSULTATS: Environ 7095 patients ont été admis pour une arthroplastie totale de la hanche au Nouveau-Brunswick au cours de la période de 7 ans à l'étude, et 170 patients sont décédés dans les 30 jours. Nous n'avons pas observé de liens entre le volume d'activité du fournisseur de soins de santé et la mortalité postopératoire dans nos modèles. L'ajustement pour tenir compte des caractéristiques contextuelles ou du volume d'activité de l'hôpital n'a eu aucune incidence sur ce lien. CONCLUSION: Nos résultats suggèrent que les patients hospitalisés afin de subir une arthroplastie de la hanche au Nouveau-Brunswick peuvent s'attendre à un risque similaire de décès, peu importe que leur fournisseur de soins de santé pratique un volume faible ou élevé d'arthroplasties totales de la hanche ou que le patient soit admis dans un petit ou un grand hôpital de la province.

Simple and Efficient Synthesis of Explosive Cocrystals containing 3,5-Dimethylpyrazol-1-yl-substituted-1,2,4,5-tetrazines.

The reaction of 3,4-dinitropyrazole, 5-nitrotetrazole, or 4-nitro-1,2,3-triazole with 1,2,4,5-tetrazines substituted with 3,5-dimethylpyrazolyl (dmp) groups results in energetic cocrystals after 1 minute of reflux and cooling to room temperature in yields of 89-92 %. Hydrogen-bonding between the dmp group to the N-H of the energetic heterocycles are the predominant interaction that stabilizes the new cocrystals. Each cocrystal packs in a different lattice structure and the cocrystals with sheet-like and herring-bone crystal packing orientations are less sensitive than the cocrystal with the interlocked structure. Electrostatic potential mapping helps rationalize why dmp-substituted tetrazines readily form cocrystals, whereas more electron-deficient pyrazolyl tetrazines do not. The calculated energetic performance of the new cocrystals approaches that of 2,4,6-trinitrotoluene (TNT) and importantly, these materials will aid in the rational design of new cocrystalline energetic materials.

Income Inequalities and Risk of Early Rehospitalization for Diabetes, Hypertension and Congestive Heart Failure in the Canadian Working-Age Population.

OBJECTIVES: In the Canadian context of universal health-care coverage, income inequalities are understudied as potentially predictive of the timings and patterns of repeat hospitalizations for diabetes, despite this condition requiring self-care practices entailing appreciable out-of-pocket expenses in daily life. In this study, we examined the relationships between income disparities and risk of earlier readmission for diabetes and commonly comorbid chronic conditions in the working-age population. METHODS: The cohort study exploited 2006 population census data linked longitudinally to 3 years of hospital records from the Discharge Abstract Database among adults 25 to 64 years of age. Multiple regression survival models were used to test the associations of income group with cause-specific times to rehospitalization for diabetes (types 1 and 2) and 5 additional conditions, controlling for other individual sociodemographics. RESULTS: The mean time to rehospitalization for diabetes was 223 days (N=4,540). Compared with those in the lowest income quintile, the adjusted risk of earlier readmission was significantly lower among inpatients in the highest income quintile for diabetes (hazard ratio [HR]=0.89; 95% confidence interval [CI], 0.80 to 0.99) and for the diabetes-concordant conditions of congestive heart failure (HR=0.81; 95% CI, 0.66 to 0.99) and hypertension (HR=0.85; 95% CI, 0.76 to 0.95). No significant associations between income and readmission intervals were observed for the discordant conditions of angina, asthma and chronic obstructive pulmonary disease. CONCLUSIONS: Delays in rehospitalization for diabetes and concordant conditions among the most affluent suggest the persistence of income-mediated differences in individuals' ability to manage these conditions. Further research is needed to understand the specific financial burdens of disease management on patients and their households that may accelerate the risk of repeat hospitalization.

[3+2] click chemistry approach to tetrazine containing polymers.

We report a [3+2] cycloaddition using 3,6-bis-propargyloxy-1,2,4,5-tetrazine and azides to synthesize energetic polymers containing 1,2,4,5-tetrazine within the scaffold. This work also includes [3+2] cycloaddition to crosslink azide containing glycidyl azide polymer (GAP). These reactions provide pathways for incorporation of 1,2,4,5-tetrazine into novel energetic materials using click-chemistry and provide an alternative polymer curing approach.

A comparative study of fragment screening methods on the p38α kinase: new methods, new insights.

The stress-activated kinase p38α was used to evaluate a fragment-based drug discovery approach using the BioFocus fragment library. Compounds were screened by surface plasmon resonance (SPR) on a Biacore(™) T100 against p38α and two selectivity targets. A sub-set of our library was the focus of detailed follow-up analyses that included hit confirmation, affinity determination on 24 confirmed, selective hits and competition assays of these hits with respect to a known ATP binding site inhibitor. In addition, functional activity against p38α was assessed in a biochemical assay using a mobility shift platform (LC3000, Caliper LifeSciences). A selection of fragments was also evaluated using fluorescence lifetime (FLEXYTE(™)) and microscale thermophoresis (Nanotemper) technologies. A good correlation between the data for the different assays was found. Crystal structures were solved for four of the small molecules complexed to p38α. Interestingly, as determined both by X-ray analysis and SPR competition experiments, three of the complexes involved the fragment at the ATP binding site, while the fourth compound bound in a distal site that may offer potential as a novel drug target site. A first round of optimization around the remotely bound fragment has led to the identification of a series of triazole-containing compounds. This approach could form the basis for developing novel and active p38α inhibitors. More broadly, it illustrates the power of combining a range of biophysical and biochemical techniques to the discovery of fragments that facilitate the development of novel modulators of kinase and other drug targets.

Discovery of GLPG1972/S201086, a Potent, Selective, and Orally Bioavailable ADAMTS-5 Inhibitor for the Treatment of Osteoarthritis.

There are currently no approved disease-modifying osteoarthritis (OA) drugs (DMOADs). The aggrecanase ADAMTS-5 is key in the degradation of human aggrecan (AGC), a component of cartilage. Therefore, ADAMTS-5 is a promising target for the identification of DMOADs. We describe the discovery of GLPG1972/S201086, a potent and selective ADAMTS-5 inhibitor obtained by optimization of a promising hydantoin series following an HTS. Biochemical activity against rat and human ADAMTS-5 was assessed via a fluorescence-based assay. ADAMTS-5 inhibitory activity was confirmed with human aggrecan using an AGC ELISA. The most promising compounds were selected based on reduction of glycosaminoglycan release after interleukin-1 stimulation in mouse cartilage explants and led to the discovery of GLPG1972/S201086. The anticatabolic activity was confirmed in mouse cartilage explants (IC50 < 1.5 µM). The cocrystal structure of GLPG1972/S201086 with human recombinant ADAMTS-5 is discussed. GLPG1972/S201086 has been investigated in a phase 2 clinical study in patients with knee OA (NCT03595618).

Structure-Based Exploration of Selectivity for ATM Inhibitors in Huntington's Disease.

Our group has recently shown that brain-penetrant ataxia telangiectasia-mutated (ATM) kinase inhibitors may have potential as novel therapeutics for the treatment of Huntington's disease (HD). However, the previously described pyranone-thioxanthenes (e.g., 4) failed to afford selectivity over a vacuolar protein sorting 34 (Vps34) kinase, an important kinase involved with autophagy. Given that impaired autophagy has been proposed as a pathogenic mechanism of neurodegenerative diseases such as HD, achieving selectivity over Vps34 became an important objective for our program. Here, we report the successful selectivity optimization of ATM over Vps34 by using X-ray crystal structures of a Vps34-ATM protein chimera where the Vps34 ATP-binding site was mutated to approximate that of an ATM kinase. The morpholino-pyridone and morpholino-pyrimidinone series that resulted as a consequence of this selectivity optimization process have high ATM potency and good oral bioavailability and have lower molecular weight, reduced lipophilicity, higher aqueous solubility, and greater synthetic tractability compared to the pyranone-thioxanthenes.

[1,2,4]Triazolo[1,5-a]pyrimidine Phosphodiesterase 2A Inhibitors: Structure and Free-Energy Perturbation-Guided Exploration.

We describe the hit-to-lead exploration of a [1,2,4]triazolo[1,5-a]pyrimidine phosphodiesterase 2A (PDE2A) inhibitor arising from high-throughput screening. X-ray crystallography enabled structure-guided design, leading to the identification of preferred substructural components. Further rounds of optimization used relative binding free-energy calculations to prioritize different substituents from the large accessible chemical space. The free-energy perturbation (FEP) calculations were performed for 265 putative PDE2A inhibitors, and 100 compounds were synthesized representing a relatively large prospective application providing unexpectedly active molecules with IC50's from 2340 to 0.89 nM. Lead compound 46 originating from the FEP calculations showed PDE2A inhibition IC50 of 1.3 ± 0.39 nM, ∼100-fold selectivity versus other PDE enzymes, clean cytochrome P450 profile, in vivo target occupancy, and promise for further lead optimization.

Optimization of Potent and Selective Ataxia Telangiectasia-Mutated Inhibitors Suitable for a Proof-of-Concept Study in Huntington's Disease Models.

Genetic and pharmacological evidence indicates that the reduction of ataxia telangiectasia-mutated (ATM) kinase activity can ameliorate mutant huntingtin (mHTT) toxicity in cellular and animal models of Huntington's disease (HD), suggesting that selective inhibition of ATM could provide a novel clinical intervention to treat HD. Here, we describe the development and characterization of ATM inhibitor molecules to enable in vivo proof-of-concept studies in HD animal models. Starting from previously reported ATM inhibitors, we aimed with few modifications to increase brain exposure by decreasing P-glycoprotein liability while maintaining potency and selectivity. Here, we report brain-penetrant ATM inhibitors that have robust pharmacodynamic (PD) effects consistent with ATM kinase inhibition in the mouse brain and an understandable pharmacokinetic/PD (PK/PD) relationship. Compound 17 engages ATM kinase and shows robust dose-dependent inhibition of X-ray irradiation-induced KAP1 phosphorylation in the mouse brain. Furthermore, compound 17 protects against mHTT (Q73)-induced cytotoxicity in a cortical-striatal cell model of HD.

Crystal structures of the three closely related compounds: bis-[(1H-tetra-zol-5-yl)meth-yl]nitramide, tri-amino-guanidinium 5-({[(1H-tetra-zol-5-yl)meth-yl](nitro)-amino}-meth-yl)tetra-zol-1-ide, and di-ammonium bis-[(tetra-zol-1-id-5-yl)meth-yl]nitramide monohydrate.

In the mol-ecule of neutral bis-[(1H-tetra-zol-5-yl)meth-yl]nitramide, (I), C4H6N10O2, there are two intra-molecular N-H⋯O hydrogen bonds. In the crystal, N-H⋯N hydrogen bonds link mol-ecules, forming a two-dimensional network parallel to (-201) and weak C-H⋯O, C-H⋯N hydrogen bonds, and inter-molecular π-π stacking completes the three-dimensional network. The anion in the molecular salt, tri-amino-guanidinium 5-({[(1H-tetra-zol-5-yl)meth-yl](nitro)-amino}-meth-yl)tetra-zol-1-ide, (II), CH9N6+·C4H5N10O2-, displays intra-molecular π-π stacking and in the crystal, N-H⋯N and N-H⋯O hydrogen bonds link the components of the structure, forming a three-dimensional network. In the crystal of di-ammonium bis-[(tetra-zol-1-id-5-yl)meth-yl]nitramide monohydrate, (III), 2NH4+·C4H4N10O22-·H2O, O-H⋯N, N-H⋯N, and N-H⋯O hydrogen bonds link the components of the structure into a three-dimensional network. In addition, there is inter-molecular π-π stacking. In all three structures, the central N atom of the nitramide is mainly sp2-hybridized. Bond lengths indicate delocalization of charges on the tetra-zole rings for all three compounds. Compound (II) was found to be a non-merohedral twin and was solved and refined in the major component.

Hexaferrocenylbenzene.

Hexaferrocenylbenzene has been synthesized by six-fold Negishi type ferrocenylation of hexabromo- or hexaiodobenzene.

The structure of Escherichia coli RusA endonuclease reveals a new Holliday junction DNA binding fold.

Holliday junction resolution performed by a variety of structure-specific endonucleases is a key step in DNA recombination and repair. It is believed that all resolvases carry out their reaction chemistries in a similar fashion, utilizing a divalent cation to facilitate the hydrolysis of the phosphodiester backbone of the DNA, but their architecture varies. To date, with the exception of bacteriophage T4 endonuclease VII, each of the known resolvase enzyme structures has been categorized into one of two families: the integrases and the nucleases. We have now determined the structure of the Escherichia coli RusA Holliday junction resolvase, which reveals a fourth structural class for these enzymes. The structure suggests that dimer formation is essential for Mg(2+) cation binding and hence catalysis and that like the other resolvases, RusA distorts its Holliday junction target upon binding. Key residues identified by mutagenesis experiments are well positioned to interact with the DNA.

Identification and Investigation of Novel Binding Fragments in the Fatty Acid Binding Protein 6 (FABP6).

Fatty acid binding protein 6 (FABP6) is a potential drug discovery target, which, if inhibited, may have a therapeutic benefit for the treatment of diabetes. Currently, there are no published inhibitors of FABP6, and with the target believed to be amenable to fragment-based drug discovery, a structurally enabled program was initiated. This program successfully identified fragment hits using the surface plasmon resonance (SPR) platform. Several hits were validated with SAR and were found to be displaced by the natural ligand taurocholate. We report the first crystal structure of human FABP6 in the unbound form, in complex with cholate, and with one of the key fragments.

Potent, Selective, and CNS-Penetrant Tetrasubstituted Cyclopropane Class IIa Histone Deacetylase (HDAC) Inhibitors.

Potent and selective class IIa HDAC tetrasubstituted cyclopropane hydroxamic acid inhibitors were identified with high oral bioavailability that exhibited good brain and muscle exposure. Compound 14 displayed suitable properties for assessment of the impact of class IIa HDAC catalytic site inhibition in preclinical disease models.

Multiparameter Lead Optimization to Give an Oral Checkpoint Kinase 1 (CHK1) Inhibitor Clinical Candidate: (R)-5-((4-((Morpholin-2-ylmethyl)amino)-5-(trifluoromethyl)pyridin-2-yl)amino)pyrazine-2-carbonitrile (CCT245737).

Multiparameter optimization of a series of 5-((4-aminopyridin-2-yl)amino)pyrazine-2-carbonitriles resulted in the identification of a potent and selective oral CHK1 preclinical development candidate with in vivo efficacy as a potentiator of deoxyribonucleic acid (DNA) damaging chemotherapy and as a single agent. Cellular mechanism of action assays were used to give an integrated assessment of compound selectivity during optimization resulting in a highly CHK1 selective adenosine triphosphate (ATP) competitive inhibitor. A single substituent vector directed away from the CHK1 kinase active site was unexpectedly found to drive the selective cellular efficacy of the compounds. Both CHK1 potency and off-target human ether-a-go-go-related gene (hERG) ion channel inhibition were dependent on lipophilicity and basicity in this series. Optimization of CHK1 cellular potency and in vivo pharmacokinetic-pharmacodynamic (PK-PD) properties gave a compound with low predicted doses and exposures in humans which mitigated the residual weak in vitro hERG inhibition.

Crystal structure of 2-diazo-imidazole-4,5-dicarbo-nitrile.

In the title compound, C5N6, all the atoms are approximately coplanar. In the crystal, mol-ecules are packed with short contact distances of 2.885 (2) (between the diazo N atom connected to the ring and a cyano N atom on a neighboring mol-ecule) and 3.012 (2) Š(between the terminal diazo N atom and an N atom of a neighboring imidazole ring).

Crystal structure of 2-azido-1H-imidazole-4,5-di-carbonitrile.

In the title compound, C5HN7, the nitrile and azido substituents are close to being coplanar with the central ring. Mol-ecules in the crystal are linked via an N-H⋯N hydrogen bond to a nitrile acceptor, forming a chain extending along the c-axis direction.