Xiao Hong Ma

Increase in Prostaglandin H synthase 2, but not Prostaglandin F2α synthase mRNA in intrauterine tissues during betamethasone-induced premature labor and spontaneous term labor in sheep

OBJECTIVE: Prostaglandin F synthase (PGFS) catalyzes reduction of prostaglandin H2 to PGF2α,. No information exists on PGFS expression and regulation during pregnancy, either mRNA or protein, in relation to labor in uterine tissues in any species. We characterized PGFS mRNA expression in ovine myometrium, endometrium, maternal and fetal placenta in betamethasone-induced premature labor and spontaneous term labor using our cloned ovine PGFS riboprobe. Prostaglandin H synthase (PGHS) 2 mRNA was evaluated simultaneously as a control whose pregnancy related changes are well known. METHODS: Poly-A or total RNA from fetal placenta, myometrium, and endometrium in control ewes at 143-147 days of gestational age (dGA, TCNL, n = 6), and ewes in spontaneous term labor at 145-147 dGA (STL, n = 6) and endometrium and maternal and fetal placenta in early control ewes not in labor (ECNL, n = 6) and betamethasone induced labor at 128-135 dGA (BL, n = 6) were analyzed for PGHS2 and PGFS mRNA. RESULTS: PGFS mRNA did not change at spontaneous term labor in myometrium, endometrium, and fetal placenta. PGFS mRNA decreased during betamethasone-induced premature labor in endometrium and maternal placenta (P < .05), but remained unchanged infetal placenta and myometrium. PGHS2 mRNA increased in endometrium, placenta, and myometrium during betamethasone-induced premature labor and spontaneous term labor. CONCLUSION: Increased PGHS2, but not PGFS mRNA was tightly associated with the onset of betamethasone-induced premature labor as well as spontaneous term labor in the endometrium, placenta, and myometrium. Transcription of PGFS mRNA may not be the rate-limiting step in the pathway contributing to increased PGF2α, at labor.

Growth, Neurobehavioral and Circadian Rhythm Development in Newborn Baboons

We measured body temperature continuously using telemetry to determine the development of circadian rhythmicity in neonatal baboons after birth. Twelve fetal baboons (nine males and three females) of known gestational age ranging from 167 to 193 d were studied. We eliminated the influence of maternal factors by hand rearing these infants from the moment of birth until 45 d of life. All infants showed steady growth in body weight, head circumference, and crown-rump length. Neurobehavioral responses including visual and auditory orientation, motor maturity, irritability, and consolability increased as a function of age. Circadian rhythms of body temperature were present in the second week of life, and the amplitude of this rhythm increased throughout the developmental period studied. The increase in the amplitude of circadian body temperature rhythm independent of environmental time cues may indicate the maturation of the brain. These neonatal nonhuman primates offer an excellent model for studying neurobehavioral development and maturation of circadian rhythms while controlling external factors in a manner that is not possible with human neonates.