A Route to Potent, Selective, and Biased Salvinorin Chemical Space

The salvinorins serve as templates for next generation analgesics, antipruritics, and dissociative hallucinogens via selective and potent agonism of the kappa-opioid receptor (KOR). In contrast to most opioids, the salvinorins lack basic amines and bind with high affinity and selectivity via complex polyoxygenated scaffolds that have frustrated deep-seated modification by synthesis. Here we describe a short asymmetric synthesis that relies on a sterically confined organocatalyst to dissociate acidity from reactivity and effect Robinson annulation of an unactivated nucleophile/unstable electrophile pair. Combined with a cobalt-catalyzed polarized diene-alkyne cycloaddition, the route allows divergent access to a focused library of salvinorins. We appraise the synthesis by its generation of multiple analogs that exceed the potency, selectivity, stability, and functional bias of salvinorin A itself.

Cycloisomerization of Olefins in Water

Preparative reactions that occur efficiently under dilute, buffered, aqueous conditions in the presence of biomolecules find application in ligation, peptide synthesis, and polynucleotide synthesis and sequencing. However, the identification of functional groups or reagents that are mutually reactive with one another, but unreactive with biopolymers and water, is challenging. Shown here are cobalt catalysts that react with alkenes under dilute, aqueous, buffered conditions and promote efficient cycloisomerization and formal Friedel-Crafts reactions. The constraining conditions of bioorthogonal chemistry are beneficial for reaction efficiency as superior conversion at low catalyst concentration is obtained and competent rates in dilute conditions are maintained. Efficiency at high dilution in the presence of buffer and nucleobases suggests that these reaction conditions may find broad application.

Cervical pessary vs vaginal progesterone for prevention of preterm birth in women with twin pregnancy and short cervix: economic analysis following randomized controlled trial

OBJECTIVE

To compare the cost-effectiveness of cervical pessary vs vaginal progesterone to prevent preterm birth and neonatal morbidity in women with twin pregnancy and a short cervix.

METHODS

Between 4 March 2016 and 3 June 2017, we performed this economic analysis following a randomized controlled trial (RCT), performed at My Duc Hospital, Ho Chi Minh City, Vietnam, that compared cervical pessary to vaginal progesterone in women with twin pregnancy and cervical length < 38 mm between 16 and 22 weeks of gestation. We used morbidity-free neonatal survival as a measure of effectiveness. Data on pregnancy outcome, maternal morbidity and neonatal complications were collected prospectively from medical files; additional information was obtained via telephone interviews with the patients. The incremental cost-effectiveness ratio was calculated as the incremental cost required to achieve one extra surviving morbidity-free neonate in the pessary group compared with in the progesterone group. Probabilistic and one-way sensitivity analyses were also performed.

RESULTS

During the study period, we screened 1113 women with twin pregnancy, of whom 300 fulfilled the inclusion criteria of the RCT and gave informed consent to participate. These women were assigned randomly to receive cervical pessary (n = 150) or vaginal progesterone (n = 150), with two women and one woman, respectively, being lost to follow-up. The rate of morbidity-free neonatal survival was significantly higher in the pessary group compared with the progesterone group (n = 241/296 (81.4%) vs 219/298 (73.5%); relative risk, 1.11 (95% CI, 1.02-1.21), P = 0.02). The mean total cost per woman was 3146 € in the pessary group vs 3570 € in the progesterone group (absolute difference, -424 € (95% CI, -842 to -3 €), P = 0.048). The cost per morbidity-free neonate was significantly lower in the pessary group compared with that in the progesterone group (2492 vs 2639 €; absolute difference, -147 € (95% CI, -284 to 10 €), P = 0.035).

CONCLUSION

In women with twin pregnancy and a short cervix, cervical pessary improves significantly the rate of morbidity-free neonatal survival while reducing costs, as compared with vaginal progesterone. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Off-DNA DNA-Encoded Library Affinity Screening

DNA-encoded library (DEL) technology is emerging as a key element of the small molecule discovery toolbox. Conventional DEL screens (i.e., on-DNA screening) interrogate large combinatorial libraries via affinity selection of DNA-tagged library members that are ligands of a purified and immobilized protein target. In these selections, the DNA tags can materially and undesirably influence target binding and, therefore, the experiment outcome. Here, we use a solid-phase DEL and droplet-based microfluidic screening to separate the DEL member from its DNA tag (i.e., off-DNA screening), for subsequent in-droplet laser-induced fluorescence polarization (FP) detection of target binding, obviating DNA tag interference. Using the receptor tyrosine kinase (RTK) discoidin domain receptor 1 (DDR1) as a proof-of-concept target in a droplet-scale competition-binding assay, we screened a 67 100-member solid-phase DEL of drug-like small molecules for competitive ligands of DDR1 and identified several known RTK inhibitor pharmacophores, including azaindole- and quinazolinone-containing monomers. Off-DNA DEL affinity screening with FP detection is potentially amenable to a wide array of target classes, including nucleic acid binding proteins, proteins that are difficult to overexpress and purify, or targets with no known activity assay.

Activity-Based DNA-Encoded Library Screening

Robotic high-throughput compound screening (HTS) and, increasingly, DNA-encoded library (DEL) screening are driving bioactive chemical matter discovery in the postgenomic era. HTS enables activity-based investigation of highly complex targets using static compound libraries. Conversely, DEL grants efficient access to novel chemical diversity, although screening is limited to affinity-based selections. Here, we describe an integrated droplet-based microfluidic circuit that directly screens solid-phase DELs for activity. An example screen of a 67 100-member library for inhibitors of the phosphodiesterase autotaxin yielded 35 high-priority structures for nanomole-scale synthesis and validation (20 active), guiding candidate selection for synthesis at scale (5/5 compounds with IC₅₀ values of 4-10 μM). We further compared activity-based hits with those of an analogous affinity-based DEL selection. This miniaturized screening platform paves the way toward applying DELs to more complex targets (signaling pathways, cellular response) and represents a distributable approach to small molecule discovery.

The effectiveness of ICSI versus conventional IVF in couples with non-male factor infertility: study protocol for a randomised controlled trial

Study questions

Does ICSI result in a higher live birth rate as compared with conventional IVF in couples with non-male factor infertility?

What is known already

ICSI is primarily indicated for severe male factor infertility. While the use of ICSI for couples with non-male factor infertility has been increasing worldwide, this is not supported by data from randomised controlled trials. Evidence from non-randomised studies suggest no benefit from ICSI compared with conventional IVF in non-male factor infertility, if not a harm.

Study design, size, duration

This randomised, open-label, multi-centre trial aims to compare the effectiveness of one ICSI cycle and one conventional IVF cycle in infertile couples with non-male factor infertility. A total of 1064 couples will be randomly allocated to an ICSI group and a conventional IVF group. The estimated duration of the study is 30 months.

Participants/materials, setting, methods

Eligible couples are those whose husbands’ total sperm count and motility are normal, have undergone ≤2 previous IVF/ICSI attempts, use antagonist protocol for ovarian stimulation, agree to have ≤2 embryos transferred and are not participating in another IVF study at the same time. Women undergoing IVM cycles, using frozen semen or having a poor fertilisation (≤25%) in previous cycle will not be eligible. Couples will be randomised to undergo ICSI or conventional IVF (1:1) with ongoing pregnancy resulting in live birth after the first embryo transfer of the started treatment cycle as the primary endpoint. All analyses will be conducted on an intention-to-treat basis. Effect sizes will be summarised as relative risk (RR), with precision evaluated by 95% CIs.

STUDY FUNDING/COMPETING INTEREST(S)

All authors declare having no conflict of interests with regards to this trial. This work was supported by a grant from MSD [MISP #57508].

Trial registration number

NCT03428919.

Trial registration date

8 February 2018.

DATE OF FIRST PATIENT’S ENROLMENT

16 March 2018.