Are serum activin A levels lower in tubal than intrauterine spontaneously conceived pregnancies?
Activin A secretion in EP is reduced and measurement of its serum levels may have the potential clinical advantage to signal the presence of EP.
Ventrally conjoined fish twins can develop cardiovascular connections during early development, enabling a normal superior twin to supply a malfunctioning twin with oxygen and nutrients. Since the yolk sac in salmonids is transparent, twinning in salmonids may be a useful model in which to study cardiovascular morphogenesis in conjoined twins.