HTS driven by fluorescence lifetime detection of FRET identifies activators and inhibitors of cardiac myosin.

Small molecules that bind to allosteric sites on target proteins to alter protein function are highly sought in drug discovery. High-throughput screening (HTS) assays are needed to facilitate the direct discovery of allosterically active compounds. We have developed technology for high-throughput time-resolved fluorescence lifetime detection of fluorescence resonance energy transfer (FRET), which enables the detection of allosteric modulators by monitoring changes in protein structure. We tested this approach at the industrial scale by adapting an allosteric FRET sensor of cardiac myosin to high-throughput screening (HTS), based on technology provided by Photonic Pharma and the University of Minnesota, and then used the sensor to screen 1.6 million compounds in the HTS facility at Bristol Myers Squibb. The results identified allosteric activators and inhibitors of cardiac myosin that do not compete with ATP binding, demonstrating high potential for FLT-based drug discovery.

Placental transfusion as an intrauterine phenomenon in deliveries complicated by foetal distress.

The details of the deliveries of 10 infants whose cords were clamped before the onset of respiration and within one minute of delivery of the chin but whose residual placental volumes were unexpectedly low are compared with 20 control infants whose cords were clamped under similar conditions but who had the expected residual placental volumes. The only statistically significant difference between these groups was in the high number of patients with foetal distress and low Apgar scores in the former group. It is concluded that placental transfusion occurred before delivery in these patients and that foetal asphyxia facilitated this transfusion, which may be the underlying mechanism of neonatal erythrocythaemia or transient tachypnoea of the newborn.