Effect of early versus delayed cord clamping on hematological status of preterm infants at 6 wk of age.

OBJECTIVE: To compare the effect of early cord clamping (ECC) vs. delayed cord clamping (DCC) on hematocrit and serum ferritin at 6 wk of life in preterm infants. METHODS: This randomized controlled trial was conducted in the delivery room and neonatal intensive care unit of a tertiary hospital. One hundred preterm infants born between 30 (0)/7 and 36 (6)/7 wk were randomized to either early or delayed cord clamping groups. Parental informed consent was obtained prior to the delivery. In the ECC group, the cord was clamped immediately after the delivery of the baby and in the DCC group; the cord was clamped beyond 2 min after the baby was delivered. Hematocrit and serum ferritin at 6 wk of life were the primary outcomes. Incidence of anemia, polycythemia and significant jaundice were the main secondary outcomes. RESULTS: The mean hematocrit (27.3 ± 3.8 % vs. 31.8 ± 3.5 %, p value 0.00) and the mean serum ferritin (136.9 ± 83.8 ng/mL vs. 178.9 ± 92.8 ng/mL, p value 0.037) at 6 wk of age were significantly higher in the infants randomized to DCC group. The hematocrit on day 1 was also significantly higher in the DCC group (50.8 ± 5.2 % vs. 58.5 ± 5.1 %, p value 0.00). The DCC group required significantly longer duration of phototherapy (55.3 ± 40.0 h vs. 36.7 ± 32.6 h, p value 0.016) and had a trend towards higher risk of polycythemia. CONCLUSIONS: Delaying the cord clamping by 2 min, significantly improves the hematocrit value at birth and this beneficial effect continues till at least 2nd mo of life.

High-throughput screen for inhibitors of transglycosylase and/or transpeptidase activities of Escherichia coli penicillin binding protein 1b.

Penicillin binding protein (PBP) 1b of Escherichia coli has both transglycosylase and transpeptidase activities, which are attractive targets for the discovery of new antibacterial agents. A high-throughput assay that detects inhibitors of the PBPs was described previously, but it cannot distinguish them from inhibitors of the MraY, MurG, and lipid pyrophosphorylase. We report on a method that distinguishes inhibitors of both activities of the PBPs from those of the other three enzymes. Radioactive peptidoglycan was synthesized by using E. coli membranes. Following termination of the reaction the products were analyzed in three ways. Wheat germ agglutinin (WGA)-coated scintillation proximity assay (SPA) beads were added to one set, and the same beads together with a detergent were added to a second set. Type A polyethylenimine-coated WGA-coated SPA beads were added to a third set. By comparison of the results of assays run in parallel under the first two conditions, inhibitors of the transpeptidase and transglycosylase could be distinguished from inhibitors of the other enzymes, as the inhibitors of the other enzymes showed similar inhibitory concentrations (IC(50)s) under both conditions but the inhibitors of the PBPs showed insignificant inhibition in the absence of detergent. Furthermore, comparison of the results of assays run under conditions two and three enabled the distinction of transpeptidase inhibitors. Penicillin and other beta-lactams showed insignificant inhibition with type A beads compared with that shown with WGA-coated SPA beads plus detergent. However, inhibitors of the other four enzymes (tunicamycin, nisin, bacitracin, and moenomycin) showed similar IC(50)s under both conditions. We show that the main PBP being measured under these conditions is PBP 1b. This screen can be used to find novel transglycosylase or transpeptidase inhibitors.