Biomedical subjects
Publications and source records attributed to S Yagel.
Adequate heparinization is considered to prevent stroke in pregnant women with prosthetic heart valves. A 21-year-old pregnant woman with a Starr-Eduards prosthetic mitral valve and atrial fibrillation experienced repeated cerebral embolic events despite full heparinization.
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Uterine anomalies are one of the various processes in the pelvic organs which present themselves as adnexal masses in pregnancy. In pregnancy associated with congenital uterine anomalies, complications are likely to occur. Ultrasonography is of great importance in early recognition of the anomalies, which can prevent unnecessary surgical intervention. A case of ultrasonic detection of uterus didelphys with unicavitary pregnancy is described.
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Dexamethasone or prednisolone, added in vitro to bilirubin-containing amniotic fluid, produces a time-dependent decrease in the 450-nm absorbance of the pigment. Neither the chemical determination of bilirubin in amniotic fluid nor the lecithin/sphingomyelin ratio as determined by thin-layer chromatography is affected by these glucocorticoids. The effect probably is not a result of displacement of bilirubin from its binding sites on albumin, because the absorbance of a solution of crystalline bilirubin at 450 nm is unaffected by added bovine serum albumin. Light scattering of amniotic fluid increases slightly when dexamethasone is added, whether or not low concentrations of bilirubin (less than 1.6 mumol/L) are present. Thus the effect on absorbance evidently is not ascribable to supersaturation and formation of a colloidal sol of bilirubin particles. This direct interference of glucocorticoids with the spectrophotometry of bilirubin in amniotic fluid prompts cautious interpretation of such data as an index to the severity of hemolytic disease of the fetus, specifically in cases of Rhesus-isoimmunization that are being treated with glucocorticoids.
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Trophoblast cells of normal first trimester human placenta share with malignant tumor cells the ability for significant cellular proliferation and invasion of basement membranes. Because tumor cell metastasis in vivo and invasion of basement membranes in vitro have recently been shown to require the expression of -GlcNAc beta 1-6 Man alpha 1-6 Man beta 1-branched complex type Asn-linked oligosaccharides in tumor cell surface glycoproteins, we decided to determine if such structures were also necessary for invasion by trophoblast cells. We report here that invasive first trimester trophoblasts express leukoagglutinin-reactive beta 1-6 branched Asn-linked oligosaccharides on their surface. Moreover, basement membrane invasion by trophoblast was significantly inhibited by pretreating the cells with swainsonine, a non-toxic inhibitor of Golgi alpha-mannosidase II which blocks beta 1-6 branching of Asn-linked oligosaccharides. The first trimester trophoblast cells pretreated with swainsonine attached more avidly to the amnion basement membrane and to an extracellular matrix (ECM) preparation compared to control non-treated erophoblast cells. Swainsonine treatment did not inhibit secretion of gelatinase or plasminogen activator activities by trophoblast cells. These results suggest that expression of beta 1-6 branched oligosaccharides in trophoblast cells may be functionally important for the implantation and placentation processes by reducing cell adhesion to ECM and thereby facilitating trophoblast cell invasion.
OBJECTIVES: This study examines the effects of interleukin-1 (IL-1) on plasminogen activator (PA) activity and prostaglandin (PG) E production in pregnant mare serum gonadotropin (PMSG)-primed granulosa cells and the potential involvement of PGE in the regulation of ovarian plasminogen activation. METHODS: Granulosa cells were obtained from PMSG-primed rat (27-day-old) ovaries and cultured in serum-free conditions for 48 hours in the absence or presence of IL-1 beta (10 ng/mL) with and without transforming growth factor-beta 1 (10 ng/mL). Cellular PA activity was measured through the conversion of plasminogen to plasmin and assay of the plasmin-mediated cleavage of [14C]-labeled globin to acid-soluble products. RESULTS: Exposure of PMSG-primed granulosa cells to IL-1 resulted in a 30% reduction (P < .05) in PA activity. Addition of hCG (1 IU/mL) to the granulosa cell cultures resulted in a 2.3-fold increase in PA activity, an effect significantly attenuated by co-administration of IL-1. The IL-1-mediated inhibition occurred concurrent with a 6.6-fold increase in the ability of the corresponding conditioned media to inhibit exogenous urokinase activity. This latter inhibitory capacity was the result of a significant increase in plasminogen activator inhibitor type 1 (PAI-1), given its abolition by a polyclonal anti-rat PAI-1 immunoglobulin G. The IL-1-mediated effects on PA/PAI-1 were accompanied by a sevenfold increase in PGE content of the spent culture medium. This response was dose dependent. The IL-1 effects on plasminogen activation and PG production were abolished by the IL-1 receptor antagonist, suggesting specific IL-1 receptor-mediated responses. Indomethacin, an inhibitor of PG biosynthesis, prevented the IL-1-induced increase in PGE accumulation but failed to affect the response of the PA system. Transforming growth factor-beta 1, a known regulator of IL-1 action, significantly attenuated the IL-1-stimulated PGE production but did not interfere with the ability of IL-1 to affect the PA system. CONCLUSIONS: The present observations suggest a pleiotropic response of PMSG-primed granulosa cells to IL-1, characterized by the induction of PAI-1 concurrent with but independent of PG production. These findings corroborate and extend earlier observations suggesting that IL-1 affects PA activity and PGE production in immature rat ovaries. Moreover, these observations support our contention that IL-1 may play a major regulatory role in the cellular events leading to ovulation and early corpus luteum formation.
Umbilical artery velocity waves were obtained by Doppler ultrasonography before, during, and after 20 episodes of fetal heart rate (FHR) variable decelerations (VD) during the active stage of labor in 8 women. During 50% of the VD periods, the umbilical artery resistance flow parameters increased significantly (p < 0.01). The increase in resistance preceded the decrease in FHR in six episodes (30%) of VD (AR-VD group; arterial resistance VD) and did not precede the change in FHR in another ten episodes (50%) of VD (VR-VD group; venous resistance VD). In the AR-VD group the FHR accelerations occurred before the decelerations in only 1 case (17%), while in the VR-VD group FHR accelerations preceded the decelerations in 8 out of the 10 episodes (80%). Using these Doppler studies, it may be possible to differentiate between two groups of VD: AR-VD - which are caused by umbilical artery occlusion and thus preceded by a measurable increase in umbilical artery resistance - and VR-VD - which are not preceded by a measurable increase in umbilical artery resistance and may be caused by fetal hypoxia.
Umbilical artery flow curves were obtained by Doppler ultrasonography before, during, and after episodes of fetal bradycardia in the active stage of labor in 6 women. Between 126 and 1,607 Doppler wave forms were analyzed for each patient. During the periods of bradycardia all the umbilical artery resistance flow parameters increased (p < 0.00001). The increase in resistance did not precede the change in heart rate. This study presents an accurate and reproducible method for continuous evaluation of the changes in the impedance of fetal blood flow during fetal heart rate changes, thereby enabling detailed assessment of circulatory disturbances occurring during labor and delivery.
Prostacyclin (PG12), a potent vasodilator, is believed to be involved in increasing permeability within the wall of the preovulatory follicle. In ovarian hyperstimulation syndrome (OHSS), increased vascular permeability has been shown to lead to massive fluid accumulation in ovarian cysts and the peritoneal cavity. The objective of the in vitro and in vivo studies reported herein was to examine the production of 6-keto PGF1 alpha (a breakdown metabolite of PG12) during the luteal phase of women who develop OHSS, as well as the capacity of human granulosa luteal cells (GLC) obtained from stimulated in vitro fertilization (IVF) cycles to synthesize PGF1 alpha in vitro in long-term cultures. The in vivo results showed that during the luteal phase of women with OHSS, there is no increase in 6-keto PGF1 alpha production compared with the levels obtained from the luteal phase of normal ovulatory women. The GLC (representing early corpus luteum function) secreted significant amounts of 6-keto PGF1 alpha, but only in the first 48 hours of culture. Human chorionic gonadotropin (hCG) had no additional augmentative effect upon the production of 6-keto PGF1 alpha throughout the culture period. It is concluded that 6-keto PGF1 alpha is not produced in significant amounts during the luteal phase, and therefore PG12 probably does not play a major role in the etiology of OHSS.
A simple alternative for microsurgical anastomosis of the fallopian tube is presented. The anastomosis is composed of a single continuous suture (8-0 nylon) extending through the serosa and muscularis, avoiding the mucosa. Experimentally this technique was performed on the uterine horns of 30 female rats and compared with the conventional interrupted suture technique on 30 additional female rats. Patency was established histologically in 100% of operated horns in both groups, with an average nidation index of 0.7 in the study group as compared with 0.6 in the conventional technique group. The results indicate that this simple method of anastomosis, which reduces operative time significantly, does not affect patency or nidation index in this model as compared with the conventional interrupted suture technique. It may, therefore, be a suitable procedure for anastomosis of equal-sized segments of the fallopian tubes, especially in cases of reversal of sterilization.