Transplacental pharmacokinetics of flecainide in the gravid baboon and fetus.

The objective of this study was to characterize the transfer of flecainide across the placenta and determine the fetal: maternal ratio of flecainide in the gravid baboon. Flecainide acetate has been especially successful for the treatment of fetal supraventricular tachycardia associated with hydrops fetalis. However, the degree of transplacental transmission remains unknown. In this study, all animals were placed under general anesthesia. Flecainide 2.5 mg/kg was administered intravenously. Percutaneous umbilical blood sampling was performed simultaneously with maternal sampling. Flecainide levels were measured using high-performance liquid chromatography with ultraviolet detection. A total of six gravid baboons were studied at an average gestational age of 132 days. The mean maternal volume of distribution at steady state was 5.1 +/- 1.8 L/kg. The mean combined elimination constant (k(el)) was 0.79 +/- 0.19 hr(-1) [95% confidence interval (CI), 0.64-0.93]. There was a linear relationship between maternal and fetal concentrations, with a ratio of fetal-to-maternal serum levels of 0.49 +/- 0.05 (95% CI, 0.39-0.59). At steady state, fetal flecainide levels are approximately 50% of maternal flecainide levels. Flecainide is rapidly distributed in the mother and fetus following a single intravenous dose with a maternal volume of distribution similar to that reported in normal healthy human adults. Since fetal levels correlate closely with maternal levels, we propose that it is possible to estimate fetal levels by monitoring maternal levels.

Bart's syndrome: microscopic, ultrastructural, and immunofluorescent mapping features.

Bart's syndrome has been clinically described as the association of congenital localized absence of skin (CLAS), epidermolysis bullosa (EB), oral mucosal lesions, and dystrophic nails. Transmission occurs through an autosomal dominant gene with complete penetrance but variable expression. It has been difficult to classify this type of EB because of lack of microscopic and ultrastructural studies on affected family members. This is the first report of microscopic, ultrastructural, and immunofluorescent mapping studies of an affected individual with the complete inherited syndrome initially described by Bart. This study is also the first to document the association of CLAS and dominant dystrophic epidermolysis bullosa by histology, electron microscopy, and immunofluorescent mapping. Our two patients and one other affected family member had diminution or absence of a specific basement membrane antigen as defined by immunofluorescence with a monoclonal antibody (KF-1) in perilesional skin.