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Biomedical subjects

I Zervoudakis

Publications and source records attributed to I Zervoudakis.

5 recordsLinked to original sources
PubMed2002

Pharmacokinetics of betamethasone in twin and singleton pregnancy.

OBJECTIVE: The aims of the study were to compare the pharmacokinetics of betamethasone in singleton pregnancy with the pharmacokinetics in twin pregnancy and to assess the adrenal suppression produced by betamethasone. STUDY DESIGN: We measured serial betamethasone and cortisol levels in 30 singleton and 21 twin pregnancies after the first dose of betamethasone and calculated the pharmacokinetic parameters for betamethasone including volume of distribution, half-life, and clearance. We also measured cord and maternal blood levels of betamethasone at the birth of infants of 13 singleton and 9 twin pregnancies. RESULTS: The half-life of betamethasone in mothers with twin pregnancies was significantly shorter than that in mothers with singleton pregnancies (7.2 +/-2.4 versus 9.0 +/- 2.7 hours; P <.017). Clearance of betamethasone in the twin pregnancies appeared greater than in singleton pregnancies (8.4 +/- 6.4 versus 5.7+/- 3.1 L/h; P =.06) but did not reach statistical significance. Volume of distribution was similar in the two groups. Because the time between the last dose of betamethasone and birth varied widely (range, 2-158 hours), mothers with a longer interval after treatment tended to have a higher cord-to-maternal betamethasone ratio than did mothers with a shorter interval in both twin and singleton pregnancies. This finding indicated delayed fetal clearance, but the correlation was weak (R (2) = 0.29 for twins and 0.08 for singletons). CONCLUSION: The shorter half-life of betamethasone in twin pregnancy than in singleton pregnancy may cause the level of betamethasone to be subtherapeutic for lung maturation in twin pregnancy.

Adult↗
PubMed1998

Perinatal monitoring of fetal well-being in the presence of congenital heart block.

We present a case of congenital complete heart block associated with maternal autoantibodies in which a normal labor and delivery could safely be allowed to proceed despite the absence of the usual tool of electronic fetal heart rate monitoring for fetal distress, by the technique of rupturing membranes and using a fetal scalp electrode electrocardiographic tracing to assess the fetal atrial rate.

Echocardiography, Doppler, Pulsed↗
PubMed1982

Changes in active and inactive renin throughout normal pregnancy.

Active and inactive renin were measured sequentially in 16 women throughout pregnancy and again post-partum. By 12 weeks, inactive renin was elevated 14-fold and fell slightly thereafter. By 12 weeks, active renin was 3.5-fold elevated. It continued to rise in 8 patients (Group A) until term, it remained stable in 6 (Group B) and in 2 it was quite variable. Between 12 and 32 weeks PRA and plasma aldosterone increased in Group A from 7.0 to 17.1 ng/ml/hr, and 20.0 to 95.7 ng/dl respectively and both were unchanged in Group B (6.5 to 8.1 ng/ml/hr and 26.5 to 24.6 ng/dl respectively). Inactive renin was higher in Group B than in Group A at 12 weeks (224 v 126 ng/ml/hr) but fell thereafter to the same stable but elevated level. Group A were younger (24 +/- 1.8 S.E. v. 30 +/- 2.2 years). These studies demonstrate that active and inactive renin increase early in pregnancy and remain elevated thereafter. In certain younger subjects, further increases in active renin and aldosterone sometimes occur and appear necessary for the maintenance of normal blood pressure.

Enzyme Activation↗