胎脂中ビタミンKの測定

抄録

Neonatal vitamin K deficiency causes hemorrhagic disease of the newborn. There have been some suggestions as to how to prevent babies from vitamin K deficiency. It is not yet clear which drug is more eff ecitve, vitamin K₁ or K₂ ( MK-n). It is recommended that prophylactic K₁ be administered parenterally to all newborn infants at a dose of 0.5 to 1.0mg by the American Academy of Pediatrics. In Japan, K₂ (MK-4) is generally administered with injection or syrup for babies or capsule for adults.

In this study, to find out the form of vitamin K present in fetus. We measured the concentrations of vitamin K in vernix caseosa of human neonate, because vitamin K is fat-soluble and may be contained abundantly in it. This is the first report of the determination of endogenous vitamin K in human vernix caseosa. Only MK-4 was found in vernix caseosa (Mean±S.D. 1.93ng/g±0.83),and K1 was not detected ( <0.05ng/g). As compared with the mean concentrations in maternal and umbilical cord plasma, in vernix caseosa there was high concentration of MK-4.

There is little vernix caseosa on the skin of neonates who are born before 32 weeks gestation or after 40 weeks. During 32 to 40 weeks gestation, vernix caseosa migth be stored up on the skin of fetus. From where vernix caseosa dose come? We suppose that it comes from the amniotic membrane. Fetus may get nutrition from placenta through the umbilical cord, and in addition to that we suppose he might get nutrition from amniotic membrane through the amniotic fluid and vernix caseosa.