Exploring S1 plasticity and probing S1' subsite of mammalian aminopeptidase N/CD13 with highly potent and selective aminobenzosuberone inhibitors.

In order to probe the S1 and S1' mammalian aminopeptidase N subsites, racemic 1- or 4-substituted 7-aminobenzocyclohepten-6-one derivatives were synthesized and evaluated for their ability to inhibit mammalian aminopeptidase N. We focused on improving the physicochemical and ADME properties of this series by targeting lipophilicity and LELP score. Some 4-heteroaryl substituted analogues displayed reduced lipophilicity and enhanced inhibition potency with Ki values in the nanomolar range.

Synthesis of amino-hydroxy-benzocycloheptenones as potent, selective, non-peptidic dinuclear zinc metalloaminopeptidase inhibitors.

Racemic trisubstituted benzocycloheptanes were synthesized and evaluated for their ability to inhibit metalloaminopeptidase activities. A highly selective nanomolar inhibitor of a prototypical 'two zinc' aminopeptidase from the M28 family was observed with these tridentate species, while bidentate analogs proved to be highly selective for the 'one zinc' M1 family of enzymes. The selectivity profile of these new, low molecular weight structures may guide the design of specific, non-peptidic inhibitors of binuclear aminopeptidases.

Moving beyond essential interventions for reduction of maternal mortality (the WHO Multicountry Survey on Maternal and Newborn Health): a cross-sectional study.

BACKGROUND: We report the main findings of the WHO Multicountry Survey on Maternal and Newborn Health (WHOMCS), which aimed to assess the burden of complications related to pregnancy, the coverage of key maternal health interventions, and use of the maternal severity index (MSI) in a global network of health facilities. METHODS: In our cross-sectional study, we included women attending health facilities in Africa, Asia, Latin America, and the Middle East that dealt with at least 1000 childbirths per year and had the capacity to provide caesarean section. We obtained data from analysis of hospital records for all women giving birth and all women who had a severe maternal outcome (SMO; ie, maternal death or maternal near miss). We regarded coverage of key maternal health interventions as the proportion of the target population who received an indicated intervention (eg, the proportion of women with eclampsia who received magnesium sulphate). We used areas under the receiver operator characteristic curves (AUROC) with 95% CI to externally validate a previously reported MSI as an indicator of severity. We assessed the overall performance of care (ie, the ability to produce a positive effect on health outcomes) through standardised mortality ratios. RESULTS: From May 1, 2010, to Dec 31, 2011, we included 314,623 women attending 357 health facilities in 29 countries (2538 had a maternal near miss and 486 maternal deaths occurred). The mean period of data collection in each health facility was 89 days (SD 21). 23,015 (7.3%) women had potentially life-threatening disorders and 3024 (1.0%) developed an SMO. 808 (26.7%) women with an SMO had post-partum haemorrhage and 784 (25.9%) had pre-eclampsia or eclampsia. Cardiovascular, respiratory, and coagulation dysfunctions were the most frequent organ dysfunctions in women who had an SMO. Reported mortality in countries with a high or very high maternal mortality ratio was two-to-three-times higher than that expected for the assessed severity despite a high coverage of essential interventions. The MSI had good accuracy for maternal death prediction in women with markers of organ dysfunction (AUROC 0.826 [95% CI 0.802-0.851]). INTERPRETATION: High coverage of essential interventions did not imply reduced maternal mortality in the health-care facilities we studied. If substantial reductions in maternal mortality are to be achieved, universal coverage of life-saving interventions need to be matched with comprehensive emergency care and overall improvements in the quality of maternal health care. The MSI could be used to assess the performance of health facilities providing care to women with complications related to pregnancy. FUNDING: UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP); WHO; USAID; Ministry of Health, Labour and Welfare of Japan; Gynuity Health Projects.

Amino-benzosuberone: a novel warhead for selective inhibition of human aminopeptidase-N/CD13.

This paper describes the design and synthesis of compounds belonging to a novel class of highly selective mammalian CD13 inhibitors. Racemic homologues of 3-amino-2-tetralone 1 were synthesised and evaluated for their ability to selectively inhibit the membrane-bound, zinc-dependent aminopeptidase-N/CD13 (EC 3.4.11.2). Some of these novel non-peptidic compounds are potent, competitive inhibitors of the mammalian enzyme, with K(i) values in the low micromolar range in spite of their minimal size (MW <200 Da). Moreover, they show an interesting selectivity profile against representative members of the aminopeptidase family, that is leucine aminopeptidase (EC 3.4.11.1), Aeromonas proteolytica aminopeptidase (EC 3.4.11.10) and the aminopeptidase activity of leukotriene A4 hydrolase (EC 3.3.2.6). The amino-benzosuberone derivative 4 is the most promising compound in terms of potency, stability and selectivity. A hypothetical binding mode of 4 to the catalytic zinc and several conserved active site residues is proposed, based on the observed structure-activity relationships, structural insights from aminopeptidase-N homologues of known three-dimensional structure.