RESUMEN
A 28-year-old G2P0010 woman with a history of COVID infection during her current pregnancy treated with monoclonal antibodies and benign gestational thrombocytopenia presented for routine prenatal care at 33 weeks' gestation. The patient was asymptomatic, but incidental tachycardia was noted on the physical exam with an irregular rhythm. An electrocardiogram (ECG) was performed and was consistent with multifocal atrial tachycardia at a rate of 144 beats per minute. The patient was started on labetalol 50 mg daily and was referred to cardiology for consultation. An echocardiogram was performed and showed dilated left ventricular cavity with a moderately reduced ejection fraction of 40%. No previous echocardiogram was available for comparison; the patient had no history of cardiac disease. The dose of labetalol was increased to 50 mg twice daily and she was admitted for digoxin loading and titration. Though fetal tolerance was excellent, her heart rate was not controlled. Digoxin was switched to flecainide and labetalol was switched to metoprolol which improved her heart rate and repeat echocardiogram showed an ejection fraction of 50%. The patient was admitted for induction of labor at 39 weeks of gestation and continued intrapartum flecainide. Metoprolol was continued intra and postpartum. Flecainide was resumed at three days postpartum due to the recurrence of atrial tachycardia and has been maintained. A repeat echocardiogram is scheduled six weeks postpartum to evaluate left ventricular function and wean off antiarrhythmics.
RESUMEN
During embryogenesis, primordial germ cells (PGCs) and somatic gonadal precursor cells (SGPs) migrate and coalesce to form the early gonad. A failure of the PGCs and SGPs to form a gonad with the proper architecture not only affects germ cell development, but can also lead to infertility. Therefore, it is critical to identify the molecular mechanisms that function within both the PGCs and SGPs to promote gonad morphogenesis. We have characterized the phenotypes of two genes, longitudinals lacking (lola) and ribbon (rib), that are required for the coalescence and compaction of the embryonic gonad in Drosophila melanogaster. rib and lola are expressed in the SGPs of the developing gonad, and genetic interaction analysis suggests these proteins cooperate to regulate gonad development. Both genes encode proteins with DNA binding motifs and a conserved protein-protein interaction domain, known as the Broad complex, Tramtrack, Bric-à-brac (BTB) domain. Through molecular modeling and yeast-two hybrid studies, we demonstrate that Rib and Lola homo- and heterodimerize via their BTB domains. In addition, analysis of the colocalization of Rib and Lola with marks of transcriptional activation and repression on polytene chromosomes reveals that Rib and Lola colocalize with both repressive and activating marks and with each other. While previous studies have identified Rib and Lola targets in other tissues, we find that Rib and Lola are likely to function via different downstream targets in the gonad. These results suggest that Rib and Lola act as dual-function transcription factors to cooperatively regulate embryonic gonad morphogenesis.