Contractile responses of the human umbilical artery to KCl and serotonin in Ca-free medium and the effects of levcromakalim.

It is known that K(ATP) channel openers inhibit the release and refilling of Ca(2+) from intracellular stores. The present study was designed to test the effects of levcromakalim in human umbilical artery (HUA) rings stimulated by serotonin (5-HT) and KCl in Ca-free medium. Umbilical cords were obtained at vaginal or cesarean deliveries from healthy, term pregnancies. After the isolation, HUA rings were placed in organ baths in solution with indomethacin (10(-5) M) and N(G)-nitro-L-arginine methyl ester (L-NAME) (10(-3) M) at 37 degrees C and aerated with 95% O(2) and 5% CO(2) for the measurement of isometric force. In Ca-free solution with Ethylene glycol-bis (ss-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) (2 mM) the contractions produced by 5-HT (10(-6) M) and KCl (40 mM) decreased significantly. Afterwards, HUA rings were treated with 5-HT and KCl in repeated manner in Ca-free medium. In contrast to KCl, 5-HT induced contractions reduced in each application, progressively. Levcromakalim (10(-4) M) abolished the contractions elicited by 5-HT. On the other hand, levcromakalim had a little but significant inhibitory effect on KCl induced contraction in Ca-free medium. These results suggest that Ca(2+) is not the only transduction pathway in KCl produced contractions of HUA smooth muscle cells.

Bone Fracture Healing with Umbilico-Placental Mononuclear Cells: A Controlled Animal Study.

BACKGROUND: Fracture healing is a significant process in orthopedics. In this controlled animal study, our aimis to expose the healing effects of cord blood umbilico-placental mononuclear cells (UPMNCs) on bone fractures. MATERIALS AND METHODS: Caesarean sections were performed on five pregnant New Zealand rabbits at term. Placentas and cords were collected. Standard closed transverse shaft fractures were created on both tibial bones of 15 baby rabbits. The right tibias were given UPMNCs; the left tibias were the control group. Histological examinations, osteoblast and osteoclast cell counts, and mechanical stabilities were compared. Anchorage of the donor cells was shown by the fluorescence in situ hybridization (FISH) technique. RESULTS: In the group injected with UPMNCs, histopathological fracture healing was faster, osteoblast and osteoclast counts were significantly increased, and the maximum load capacity was higher. The presence of XX and XY chromatins on the same slide revealed the anchorage of female donor cells on male tissues. CONCLUSION: The effects of umbilico-placental mononuclear cells on bone healing are histopathological healing priority, increased osteoblastic and osteoclastic activities (bone turnover), and better mechanical stability.