Prenatal findings and neonatal immature gastric teratoma.

Immature teratoma of the stomach in the neonate is extremely rare.1(,)2 This report outlines a case of giant immature teratoma of the stomach, which was detected by prenatal ultrasonography in the third trimester as an echogenic mass contiguous with the stomach bubble. It increased from 4.5 cm in diameter to 7 cm between 34 and 37 weeks gestation. The baby was delivered by elective caesarean section at 37 weeks gestation. Neonatal imaging highlighted a differential diagnosis of nephroblastoma, neuroblastoma, pancreatoblastoma and teratoma. The infant underwent surgical excision of the abdominal mass on the 10th day of life. Histology revealed grade III immature gastric teratoma arising from the posterior wall of stomach, outlining the unknown implications of such a designation in an extraovarian site. The infant made a good postoperative recovery and is currently well 9 months later, without adjuvant therapy, and with no evidence of recurrent disease.

Effects of thrombin, PAR-1 activating peptide and a PAR-1 antagonist on umbilical artery resistance in vitro.

BACKGROUND: The non-thrombotic effects of thrombin in cardiovascular tissues, as mediated via the protease activated receptors (PARs), and particularly PAR-1, have been the focus of much recent research. The aims of this study were to evaluate the effects of thrombin, a specific PAR-1 activating peptide (PAR1-AP), and a PAR-1 antagonist on human umbilical artery tone in vitro. METHODS: Human umbilical artery samples were obtained from 17 women at term. Arterial rings were suspended under physiologic conditions for isometric recording. The in vitro effects of thrombin (0.5 units/mL to 3 units/mL), PAR1-AP TFLLR-NH2 [10(-9) to 10(-6) M], and PAR-1 antagonist (N-trans cinnamoyl- p-fluoroPhe-p-guanidinoPhe-Leu-Arg-Orn-NH2) [10(-9) M to 10(-5) M] on umbilical artery tone were measured. RESULTS: Both thrombin and TFLLR-NH2 exerted a potent cumulative vasodilatory effect on human umbilical artery resistance (P < 0.001). The mean net maximal inhibition (MMI) for thrombin was 53.05% (n = 6; SEM = 1.43) at tissue bath concentration of 3 units/mL. The MMI with TFLLR-NH2 was 61.50 % (n = 6; SEM = 1.43) at bath concentration of 10(-6) M. In comparison to vehicle control, the PAR-1 antagonist did not show a significant relaxant or contractile effect (P > 0.05). CONCLUSION: These findings highlight a potential role for thrombin and PAR-1 receptors in vascular regulation of feto-placental blood flow in normal pregnancy, and in association with the vascular lesions associated with IUGR and pre-eclampsia.

Rho A/Rho kinase mRNA and protein levels in human myometrium during pregnancy and labor.

OBJECTIVE: To quantify mRNA levels of Rho A, and rho-associated coil-forming kinases I and II (ROCK I and ROCK II) in human pregnant (before and after labor onset) and nonpregnant myometrium, and to investigate protein expression of Rho A, ROCK I, and ROCK II in these three tissue types. METHODS: Real-time fluorescence reverse transcriptase-polymerase chain reaction (RT-PCR) using primers for Rho A, ROCK I, and ROCK II was performed on total RNA isolated from the three tissue types under investigation. Western blot analysis using antibodies specific to Rho A, ROCK I, and ROCK II was performed on protein isolated from the three tissue types. RESULTS: Real-time fluorescence RT-PCR, using primers for Rho A, ROCK I, and ROCK II, revealed Rho A mRNA expression was significantly greater in human pregnant myometrium after labor onset, in comparison to pregnant myometrium before labor onset (P < .05), or nonpregnant myometrium (P < .01). ROCK I and ROCK II mRNA expression levels were similar in the three tissue types (P > .05). With Western blot analysis, using antibodies specific to Rho A, ROCK I, and ROCK II, Rho A protein levels were significantly lower in pregnant (before and after labor onset) in comparison to nonpregnant myometrium (P < .01). ROCK I protein levels were similar in the three tissue types (P > .05). No signal for ROCK II was detected in myometrial tissue. CONCLUSIONS: These results outline the presence of the Rho A/Rho kinase system in modulating contractility of human myometrium. Total Rho A protein expression is down-regulated in the third trimester of pregnancy while up-regulation of Rho A mRNA occurs with labor onset.

Effects of polyamines on human umbilical artery tone in vitro.

OBJECTIVE: Polyamines act as endogenous modulators of cell function and excitability. There are no data in relation to their effects on the human fetoplacental circulation. The aim of this study was to investigate the effects of the polyamines, spermine, and spermidine on human umbilical artery resistance in vitro. METHODS: Isometric tension recordings were performed under physiologic conditions on human umbilical arterial rings (n = 12). The in vitro effects of spermine and spermidine (at concentrations ranging between 10(-9) M to 10(-3) M) were measured, and compared with those measured in vehicle control experiments. The maximal inhibition (MMI) at the highest concentration and the pD2 (-log EC50) values for each compound were calculated and compared. RESULTS: Spermine and spermidine exerted a potent relaxant effect on human umbilical arterial tone in comparison to vehicle control experiments. The MMI +/- SEM for spermine was 18.41 +/- 1.437% (n = 6; P <.001) and for spermidine was 38.31 +/- 3.572% (n = 6; P <.001). There was no difference observed between the pD2 +/- SEM values for spermine (5.78 +/- 1.54; n = 6) and spermidine (6.27 +/-0.85; n = 6) (P = .517). CONCLUSION: The polyamines spermine and spermidine exert a potent relaxant effect on human umbilical artery tone suggestive of an endogenous role for these compounds in vasomotor regulation of the fetoplacental circulation.

Anti-hypertensive therapy and the feto-placental circulation: effects on umbilical artery resistance.

OBJECTIVE: To investigate and compare the direct effects of compounds used in the treatment of hypertensive disease in pregnancy on human umbilical artery resistance in vitro. METHODS: Isometric tension recordings were performed under physiological conditions on human umbilical arterial rings (n=30). The in vitro effects of labetolol, hydralazine, alpha-methyldopa, nifedepine and magnesium sulphate (at concentration ranges from 1 nanomolar to 1 millimolar), and their respective vehicle controls, were measured. Results were expressed as -logEC50 (pD2) and mean maximal inhibition values for each compound. RESULTS: All compounds investigated, except alpha methyldopa, exerted a significant relaxant effect on umbilical arterial tone. Alpha-methyldopa was significantly less potent when compared to all other compounds (mean maximal inhibition value [20.89+/-7.99%] versus all other agents [range 63.15+/-8.70-84.12+/-3.84%] (P<0.01)). The dose response curve of nifedipine yielded a significantly greater PD2 value when compared to that of hydralazine, labetalol, and magnesium sulphate (PD2 value [5.82+/-0.34] versus the above groups [range 3.10+/-0.09-3.52+/-0.14] (P <0.01)). CONCLUSION: These findings demonstrate that agents commonly used for the treatment of hypertensive disease in pregnancy, excluding alpha-methyldopa, have significant direct effects on the feto-placental circulation. These results suggest that alpha-methyldopa administration during pregnancy is less likely to produce significant direct effects on fetal vasculature then other agents used.

Human chorionic gonadotrophin relaxation of human pregnant myometrium and activation of the BKCa channel.

The uterorelaxant effect of human chorionic gonadotropin (hCG) is regarded as an important mediator in maintenance of uterine quiescence during pregnancy with clinical potential for tocolysis, the mechanisms of which are unknown. The large conductance calcium-activated K(+) channel (BK(Ca)) is ubiquitously encountered in human uterine tissue and plays a significant role in modulating myometrial cell membrane potential and excitability. The objective of this study was to investigate the involvement of BK(Ca) channel function in the response of human myometrial cells to hCG. Single electrophysiological BK(Ca) channel recordings from freshly dispersed myocytes were obtained in the presence and absence of increasing hCG concentrations. Isometric tension studies, investigating the effects of hCG on isolated myometrial contractions, in the presence and absence of the BK(Ca) channel blocker, iberiotoxin, were performed. The hCG significantly increased the open-state probability of these channels in a concentration-dependent manner [control 0.036 +/- 0.01; 1 IU/ml hCG 0.065 +/- 0.014 (P = 0.262); 10 IU/ml hCG 0.111 +/- 0.009 (P = 0.001); and 100 IU/ml hCG 0.098 +/- 0.004 (P = 0.007)]. In vitro functional studies demonstrated that hCG exerted a significant concentration-dependent relaxant effect on human myometrial tissue. This effect was significantly attenuated by preincubation with iberiotoxin (P < 0.05). These findings outline that activation of BK(Ca) channel activity may explain the potent uterorelaxant effect of hCG.