Incubation of phenobarbital-induced rat liver microsomes with 2,2',5,5'-tetrachlorobiphenyl (TCB) yielded about 30% of the substrate as 3-hydroxy-TCB, 3,4-dihydroxy-TCB, 3,3'-dihydroxy-TCB (tentative identification), and 3,4-dihydro-3,4-dihydroxy-TCB in relative amounts of about 1:1:0.05:0.05. Under identical conditions, 2,2',5,5'-tetrachlorobiphenyl 3,4-oxide (TCBO) yielded about 45% of the su...

hyperbilirubinemia is a common problem during neonatal period especially in preterm neonates. transcutaneous bilirubin measurement (tcb) by special devices had been documented as an effective tool for predicting neonatal jaundice in full term neonate, but for preterm infants the present evidences are controversial. we carried out a prospective study in shariati hospital nicu. 126 paired tcb/tot...

OBJECTIVES To provide data on the natural course of transcutaneous bilirubin (TcB) levels in neonates before the development of significant hyperbilirubinemia, and to assess the effect of different demographic and perinatal factors on the rate of TcB increase. METHODS We analyzed 2454 TcB measurements from 419 neonates before the development of significant hyperbilirubinemia. Mean TcB values ...

OBJECTIVE To characterize discrepancies between transcutaneous bilirubin (TcB) measurements and total serum bilirubin (TSB) levels among newborns receiving care at multiple nursery sites across the United States. METHODS Medical records were reviewed to obtain data on all TcB measurements collected during two 2-week periods on neonates admitted to participating newborn nurseries. Data on TSB ...

The metabolism of the polychlorinated biphenyl congener 3,3',4,4'-tetrachlorobiphenyl (TCB) was examined in vitro and in vivo in the marine fish scup (Stenotomus chrysops). Untreated scup liver microsomes catalyzed metabolism of TCB with an estimated KM of 0.7 microM, at a rate < or = 0.13 pmol/min/mg. Metabolism was NADPH-dependent and inhibited by cytochrome c and CO, indicating cytochrome P4...

The accuracy of transcutaneous bilirubin (TcB) measurements obtained with a Bilicheck device in 70 preterm neonates before phototherapy and during phototherapy from the exposed and unexposed skin of the forehead (under the eye patch) was evaluated by comparing the TcB with the total serum bilirubin (TSB) that was performed within +/- 30 minutes of the TcB measurements. The correlation and propo...

Background: Neonatal hyperbilirubinemia leads to bilirubin neurotoxicity. Noninvasive transcutaneous bilirubin (TcB) levels can be used as a screening tool for total serum bilirubin (TSB) levels. Objective: To evaluate the correlation of TcB for TSB levels before, during and after phototherapy and find the most reliable cutoff values of TcB levels with the highest sensitivity and specificity fo...

INTRODUCTION Transcutaneous bilirubin (TcB) measurement in newborns has been studied extensively in the non-Hispanic population, but its usefulness in the Hispanic population remains unclear. We evaluate the accuracy of TcB measurements in assessing jaundice in Hispanic neonates by using total serum bilirubin (TSB) measurements as the reference standard and determine the TcB level that can be u...

The transformation of 1,2,4-trichlorobenzene (1,2,4-TCB) at initial concentrations in nano- and micromolar ranges was studied in batch experiments with Burkholderia sp. strain PS14. 1,2,4-TCB was metabolized from nano- and micromolar concentrations to below its detection limit of 0.5 nM. At low initial 1,2,4-TCB concentrations, a first-order relationship between specific transformation rate and...