Fetal Placental Tissue Research Articles

Clinical aspects, prenatal diagnosis, and pathogenesis of trisomy 16 mosaicism

Introduction: Analysis of data from cases of trisomy mosaicism can provide insight for genetic counselling after prenatal diagnosis and for the elucidation of the pathogenesis of trisomy during pregnancy. Methods:...

Adrenomedullin in perinatal medicine

This review will consider whether adrenomedullin (AM) plays a role in the different aspects of perinatal medicine: contributing to maternal systemic vasodilatation during pregnancy, regulating uterine and placental blood flow, being involved in the process of implantation and participating in uterine quiescence prior to parturition. In addition, this will also consider whether a modification of AM secretion contributes to some pathological conditions in pregnancy such as preeclampsia and impairment of fetal growth. The biosynthesis of AM increases in gravid rats and in pregnant women, and the placenta represents an important site of AM production during pregnancy. Both the peptide and its receptors have been found in the uterus, placenta, fetal membranes and cord vessels, and fetal membranes and placental tissues in culture secrete AM. AM contributes to maternal systemic vasodilatation, the placental vessels are relaxed by AM in a dose-dependent manner and AM is expressed in the fetoplacental and umbilical vascular endothelium where basal production of AM contributes to low fetoplacental vascular resistances. Controversy exists over the status of circulating and placental AM in preeclampsia and of the relative contribution of AM to impaired fetoplacental circulation and fetal growth. Moreover, the uterus expresses AM mRNA and exogenous AM relaxes the myometrium in a dose-dependent manner; however, clinical studies have shown that AM does not decrease before the onset of parturition. Rather, AM secretion increases during spontaneous labor and in preterm delivery.

Bovine Retained Placenta: Hormonal Concentrations in Fetal and Maternal Placenta

The aim of this study was to evaluate the relationship between the occurrence of retention of the fetal membranes (RFM) and the hormonal concentrations of progesterone, estradiol-17β, prostaglandin E 2 (PGE 2), prostaglandin F 2α (PGF 2α), oxytocin (OT), oxytocin receptor (OT-R), endothelin-1 and angiotensin II (Ang II) in the placental tissues of cattle. Parturition was induced in nine Holstein cows by a single injection of PGF 2α on Day 274 of gestation. Six out of nine cows in the induced group did not release the fetal membranes within 12 h after parturition and served as the RFM group, and the remaining three cows in that group, which released their fetal membranes within 12 h, served as the non-RFM group. Five other cows calved spontaneously and served as controls. The placental tissues were collected immediately (0 h) and at 6 h after parturition. The hormonal concentrations were measured by enzyme immunoassay in maternal and fetal placental tissues from RFM, non-RFM and control cows. There were no differences in P4 and E2 concentrations among the RFM, non-RFM and control groups. The mean PGF 2α concentration of the RFM group was lower than those of the non-RFM and control groups in the maternal part of the placenta. In maternal tissues, the OT and OT-R concentrations in the RFM group were lower than those at 0 and 6 h after parturition in the non-RFM group. Additionally, the Ang II concentration of the RFM group in both the maternal and fetal parts of placental tissues tended to be higher than those of the other groups. In conclusion, the present results suggest that ET-1 and Ang II may play differential tissue-specific roles in the placental unit that may amplify the local endocrinological cascade involving OT, OT-R and PGF 2α interactions which are necessary for normal placental separation in the cow.

Prostaglandin E2 9-keto reductase activity in bovine retained and not retained placenta

Prostaglandin E2 9-keto reductase (9-KPR) activity shifts reversibly PGE2 into PGF2 α and may be responsible for the control of prostaglandins (PGs) levels in, among others, placental tissues. The retention of fetal membranes in cows is the postpartum disorder where the disturbances in PGs metabolism have been reported. It has been argued whether these disturbances are due to alterations in 9-KPR activity. In this study, the activity of the enzyme was determined in maternal and fetal bovine placental tissues which were divided into 6 groups as follows: (A) caesarian section before term without retained fetal membranes (n=10), (B) caesarian section before term with retained fetal membranes (n=10), (C) caesarian section at term without retained fetal membranes (n=12), (D) caesarian section at term with retained fetal membranes (n=12), (E) spontaneous delivery at term without retained fetal membranes (n=12), (F) spontaneous delivery at term with retained fetal membranes (n=12). The enzyme activity was measured spectrophotometrically and expressed in nanokatals (nkat) per protein content. The activity increased towards parturition and was significantly higher in maternal than in fetal part of placenta in all groups examined. The significantly higher values in retained than in not retained placental tissues were observed in the samples examined. The present results indicate that the disturbances in 9-KPR activity in bovine retained placenta exist but their reasons still require further experiments.

Expression of Matrix Metalloproteinase (MMP)-2 and MMP-9 in Human Placenta and Fetal Membranes in Relation to Preterm and Term Labor

Extensive extracellular matrix (ECM) remodeling is found in many processes during human parturition at term and preterm. These include cervical ripening, fetal membrane rupture, and placental detachment from the maternal uterus. Matrix metalloproteinases (MMPs) are the main mediators of ECM degradation. The present study was designed to investigate the expression of MMP-2 and MMP-9 in human fetal membranes (FMs) and placental (PL) tissues with or without labor at preterm and term parturition. Both zymography and Western blot analysis showed that MMP-9 was significantly (P < 0.01) increased in preterm and term labor FM, compared with nonlabor. Term labor PL also had a much higher (P < 0.05) level of MMP-9 than that of term nonlabor. No significant difference in MMP-2 expression was found between labor and nonlabor tissues. Immunolocalization studies revealed a specific distribution pattern for MMP-2 and MMP-9. MMP-2 was localized to the amnion mesenchyme, chorion laeve trophoblast, decidua parietalis, and blood vessels in PL villi. MMP-9 was localized mainly to amnion epithelia, chorion laeve trophoblast, decidua parietalis, and PL syncytiotrophoblasts. Separate cell culture from different layers of FM and culture of purified PL trophoblast cells showed that PL syncytiotrophoblast and amnion epithelial cells exclusively produced MMP-9; chorion trophoblast cells secreted both MMP-2 and MMP-9, but amnion mesenchymal cells produced only MMP-2. We concluded that MMP-2 and MMP-9 exhibited cell-specific expression in the human PL. An increase in MMP-9 expression may contribute to degradation of the ECM in the FM and PL, thereby facilitating FM rupture and PL detachment from the maternal uterus at labor, both preterm and term.

Expression of matrix metalloproteinase (MMP)-2 and MMP-9 in human placenta and fetal membranes in relation to preterm and term labor.

Extensive extracellular matrix (ECM) remodeling is found in many processes during human parturition at term and preterm. These include cervical ripening, fetal membrane rupture, and placental detachment from the maternal uterus. Matrix metalloproteinases (MMPs) are the main mediators of ECM degradation. The present study was designed to investigate the expression of MMP-2 and MMP-9 in human fetal membranes (FMs) and placental (PL) tissues with or without labor at preterm and term parturition. Both zymography and Western blot analysis showed that MMP-9 was significantly (P < 0.01) increased in preterm and term labor FM, compared with nonlabor. Term labor PL also had a much higher (P < 0.05) level of MMP-9 than that of term nonlabor. No significant difference in MMP-2 expression was found between labor and nonlabor tissues. Immunolocalization studies revealed a specific distribution pattern for MMP-2 and MMP-9. MMP-2 was localized to the amnion mesenchyme, chorion laeve trophoblast, decidua parietalis, and blood vessels in PL villi. MMP-9 was localized mainly to amnion epithelia, chorion laeve trophoblast, decidua parietalis, and PL syncytiotrophoblasts. Separate cell culture from different layers of FM and culture of purified PL trophoblast cells showed that PL syncytiotrophoblast and amnion epithelial cells exclusively produced MMP-9; chorion trophoblast cells secreted both MMP-2 and MMP-9, but amnion mesenchymal cells produced only MMP-2. We concluded that MMP-2 and MMP-9 exhibited cell-specific expression in the human PL. An increase in MMP-9 expression may contribute to degradation of the ECM in the FM and PL, thereby facilitating FM rupture and PL detachment from the maternal uterus at labor, both preterm and term.

Pregnancy derived from mitochondria transfer (MIT) into oocyte from patient’s own cumulus granulosa cells (cGCs).

Objective: The mitochondrial DNA (mtDNA) is not protected by histones and constantly exposed in high level of reactive oxygen species (ROS) and free radicals in the matrix of mitochondria. The current study discloses that mtDNA 4977 deletions in compromized human oocytes may range from 32.8% (Brenner et al., 1998) to 49% (Chen et al., 1995). Furthermore, any mtDNA rearrangement is even higher in 50.5% of oocytes (Barrett et al., 2000). Although live birth has been achieved following transfer of anucleate donor oocyte cytoplasm into recipient eggs (Cohen et al., 1997), mtDNA inheritance and mtDNA heteroplasmy has been found in fetal cord blood and placental tissues. However, microinjection of purified mitochondria from granulosa cells could suppress the progress of apoptosis in cultured mouse oocyte by 50% (Perez et al., 2000) indicating the “rescue effect” of cGCs mitochondria for compromised mouse oocyte developed in vitro.

Non-enzymatic Antioxidative Defence Mechanisms Against Reactive Oxygen Species in Bovine-retained and not-retained Placenta: Vitamin C and Glutathione

Vitamin C and glutathione (GSH) are water-soluble antioxidants which take part in defence mechanisms against reactive oxygen species (ROS). They may also be involved in processes of releasing/retaining bovine fetal membranes. Hence vitamin C, reduced (GSH) and oxidised (GSSG) glutathione levels were determined in retained and not-retained bovine fetal membranes in order to describe the non-enzymatic antioxidative status. Placental samples were collected immediately after spontaneous delivery or during caesarean section before term and at term, and 6 groups were formed as follows: (A) pre-term caesarean section without retained placenta; (B) pre-term caesarean section with retained placenta; (C) term caesarean section without retained placenta; (D) term caesarean section with retained placenta; (E) spontaneous delivery without retained placenta and (F) spontaneous delivery with retained placenta. Homogenates of maternal and fetal placental tissues were prepared, and vitamin C, GSH and GSSG were measured spectrophotometrically. Vitamin C levels were significantly higher in the maternal part than in the fetal part of the placenta in all groups examined. In retained placenta cases the levels were significantly lower than in control cows, except in pre-term groups. GSH concentrations were significantly higher in placentas without retention than with retention. GSSG levels showed the opposite relationship and were significantly higher in samples with retention of fetal membranes than in controls. Further experiments on antioxidative as well as oxidative status in bovine placenta are necessary.

Changes in the temporal and spatial expression of H beta 58 during formation and maturation of the chorioallantoic placenta in the Rat.

Cloning and sequencing of a cDNA amplified by RNA fingerprinting at the implantation site of pregnant rats revealed 80% similarity with H beta 58, previously shown to be essential for formation of the chorioallantoic placenta in the mouse. H beta 58 mRNA was detected in the endometrium of hormonally sensitized rats stimulated to undergo decidualization and in the contralateral uterine horns lacking a decidual stimulus, indicating that uterine expression of H beta 58 mRNA did not require decidualization or the presence of a blastocyst. Immunodetection in the early postimplantation uterus (Days 6-8 of pregnancy) showed H beta 58 localized in the luminal and glandular epithelia and some stromal cells. Decidual cells at Day 6 of pregnancy expressed H beta 58, and by Day 9 of pregnancy, the protein localized throughout the maternal decidua. The temporal and spatial distribution of H beta 58 in the developing chorioallantoic placenta was assessed at Days 10, 12, and 14 of pregnancy. Immunoreactive H beta 58 localized to erythroid cells within the developing fetal vasculature of the chorioallantoic primordia at Day 10 of pregnancy. By Day 12, the fetal vasculature extended into the placental labyrinth, and the erythroid stem cells continued to strongly express H beta 58. At Day 14 of pregnancy, immunoreactivity became evident in the trophoblast giant cells and syncytiotrophoblast of the fetal placenta. As the chorioallantoic placenta matured (Day 18), H beta 58 mRNA was 3.6-fold higher in the labyrinth compared with the junctional region. Stable cell lines (HRP/LRP) isolated from the rat labyrinthine placenta expressed H beta 58 mRNA and protein. The expression pattern of H beta maternal and fetal placental tissues and its early expression in fetal erythroid stem cells during formation and maturation of the chorioallantoic placenta suggest that H beta 58 plays key roles in the regulatory networks that control hematopoietic development and placentation.

Effect of a high maternal dietary intake during mid-gestation on components of the utero-placental insulin-like growth factor (IGF) system in adolescent sheep with retarded placental development

The aim of the present study was to investigate the effects of administering a high plane diet during early to mid-gestation on the uterine and placental insulin-like growth factor (IGF) system and on systemic IGF-I concentrations in pregnant adolescent ewes with restricted placental growth. Embryos recovered from superovulated ewes inseminated by a single sire were transferred in singleton to the uterus of adolescent recipients. After transfer ewes were offered a high (H) or moderate (M) amount of a complete diet calculated to promote rapid or normal maternal growth rates, respectively. Five ewes from each group were switched from either M to H or H to M diets at day 52 of gestation. Maternal and fetal blood samples and placental tissues were collected from all animals at day 104. Ewes on the high plane diet from mid-gestation (HH, MH groups) had restricted placental mass (P < 0.01) and tended to have smaller fetuses. This was associated with increased maternal plasma IGF-I concentrations (P < 0.001). The pattern of expression of components of the IGF system in the uterus and placenta was studied by in situ hybridization. IGF-I mRNA concentrations were below the limit of detection. IGF-II mRNA expression was high in the fetal mesoderm and present in maternal stroma, but was not influenced by nutritional treatment. In contrast, IGF binding protein 1 (IGFBP-1) mRNA expression was higher (P < 0.05) and IGFBP-3 mRNA expression was lower (P < 0.05) in the endometrial glands of ewes in HH and MH groups. In the fetal trophoblast, IGFBP-3 mRNA expression was higher in the MH group. Type 1 IGF receptor expression was increased (P < 0. 01) in the luminal epithelium of the HM group and IGFBP-2 mRNA expression was highest in the placentome capsule of ewes in the HH group. Together, these results indicate that reprogramming of the uterine and placental IGF axis by maternal nutrition could contribute to placental growth retardation in growing adolescent sheep.

Effect of a high maternal dietary intake during mid-gestation on components of the utero-placental insulin-like growth factor (IGF) system in adolescent sheep with retarded placental development

The aim of the present study was to investigate the effects of administering a high plane diet during early to mid-gestation on the uterine and placental insulin-like growth factor (IGF) system and on systemic IGF-I concentrations in pregnant adolescent ewes with restricted placental growth. Embryos recovered from superovulated ewes inseminated by a single sire were transferred in singleton to the uterus of adolescent recipients. After transfer ewes were offered a high (H) or moderate (M) amount of a complete diet calculated to promote rapid or normal maternal growth rates, respectively. Five ewes from each group were switched from either M to H or H to M diets at day 52 of gestation. Maternal and fetal blood samples and placental tissues were collected from all animals at day 104. Ewes on the high plane diet from mid-gestation (HH, MH groups) had restricted placental mass (P < 0.01) and tended to have smaller fetuses. This was associated with increased maternal plasma IGF-I concentrations (P < 0.001). The pattern of expression of components of the IGF system in the uterus and placenta was studied by in situ hybridization. IGF-I mRNA concentrations were below the limit of detection. IGF-II mRNA expression was high in the fetal mesoderm and present in maternal stroma, but was not influenced by nutritional treatment. In contrast, IGF binding protein 1 (IGFBP-1) mRNA expression was higher (P < 0.05) and IGFBP-3 mRNA expression was lower (P < 0.05) in the endometrial glands of ewes in HH and MH groups. In the fetal trophoblast, IGFBP-3 mRNA expression was higher in the MH group. Type 1 IGF receptor expression was increased (P < 0. 01) in the luminal epithelium of the HM group and IGFBP-2 mRNA expression was highest in the placentome capsule of ewes in the HH group. Together, these results indicate that reprogramming of the uterine and placental IGF axis by maternal nutrition could contribute to placental growth retardation in growing adolescent sheep.

Amniotic fluid nitric oxide metabolite levels and nitric oxide synthase localization in feto-placental tissues are modified in association with human labor

Nitric oxide (NO) has a relaxant effect on uterine smooth muscle and may be implicated in maintaining uterine quiescence during pregnancy. In order to investigate the role of nitric oxide in human parturition, we have measured NO metabolite levels in maternal and fetal compartments in association with labor, both at term and preterm. We have also examined the localization and distribution of NO synthase (NOS) isoforms in placentas and fetal membranes after term and preterm delivery by means of immunohistochemistry. Although no differences were present in maternal and fetal blood and in maternal urine among groups, we found that NO metabolite concentrations were higher in amniotic fluid collected from women in labor than in non-laboring patients, both at term (15.4±1.6 vs. 6.8±0.6 μM/mg creatinine) and preterm (16.7±2.0 vs. 7.0±0.8 μM/mg creatinine). Ir-bNOS staining appeared to be decreased in fetal membranes collected after spontaneous labor at term and preterm. In contrast, a stronger staining for iNOS was detected in trophoblast cells of fetal membranes from women in labor than in those from non-laboring women. We suggest that NOS isoenzymes in fetal placental tissues are differently regulated and might play different roles during pregnancy.

Feto-maternal anchorage in epitheliochorial and endotheliochorial placental types studied by histology and microvascular corrosion casts

Summary The three-dimensional representation of placental vasculature by scanning electron microscopy of corrosion casts, and subsequent comparison to conventional histology, helps to explain different patterns of feto-maternal placental anchoring. Anchorage always means that fetal and maternal placental tissues indent into each other and different types can be distinguished morphologically. Complexity increases through the species studied here: pig: simply folded with intersectioned ridges; one-humped camel: ridges or primitive microcotyledons; horse: villous, microplacentomes; cow and sheep: villous trees forming placentomal cotyledons; cat and mink: lamellar and labyrinthine-like. In the epitheliochorial species, detachment of the afterbirths from the uterus takes place along the contact surface of the uterine epithelium and the chorion or trophoblast, respectively. Too firm an anchorage is encountered in the bovine, where a retention of the afterbirth is common. Anchorage in the endotheliochorial carnivores, cat and mink, is very complex and firm, thus guaranteeing good conditions for placental exchange and minimizing clinical problems. The detachment of the afterbirth is different and apparently easy, as it does not take place along the feto-maternal interface, but in the junctional zone of the zonary placenta, thus representing a deciduate placental type.

Activity of 72-kDa and 92-kDa matrix metalloproteinases in placental tissues of cows with and without retained fetal membranes

This study compared the activity of matrix metalloproteinases (MMP-2 and MMP-9) in retained and non-retained bovine placenta. The activities of MMPs and their zymogens were measured in fetal and maternal placental tissues from control cows (group B) and animals affected with retention of fetal membranes (group A) using a zymography technique on 10 per cent SDS polyacrylamide gels. The activity of proMMP-9 detected only in the maternal part of the placenta was lower in group A than in group B. ProMMP-2 activity was higher in group A than in group B in both tissues. The active forms of MMP-2 were observed in the maternal and fetal part of placenta in group B, but only the 68-kDa form was detected in the placental tissues of group A. The differences in enzyme activity between the groups and the lack of 64- and 60-kDa active forms of MMP-2 in the maternal and fetal parts of the retained placenta may have influenced the hydrolysis of collagen and the proper release of fetal membranes.

Equine inhibin/activin beta A-subunit mRNA is expressed in the endometrial gland, but not in the trophoblast, during pregnancy.

The expression of both inhibin alpha- and inhibin/activin beta A-subunit mRNA was examined in equine uteroplacental tissues collected during pregnancy (days 90 to 300). Northern blot analysis revealed that 5 transcripts (7.0, 4.1, 3.4, 2.6, 1.5 kb) of beta A-subunit were present, and the most abundantly expressed transcript was the 1.5 kb one. Relatively high levels of the 1.5 kb transcript were seen in the second trimester of pregnancy compared to what was found in the third trimester. To identify the tissue localization of beta A-subunit mRNA, in situ hybridization was performed, and the positive signal was observed exclusively in the endometrial glands, but not in the fetal placental tissue (trophoblast) at days 150, 210, and 300 of pregnancy. On the other hand, inhibin alpha-subunit transcript could not be detected at any stage of pregnancy examined either by Northern blot analysis or in situ hybridization. Although the factor(s) regulating the gene expression of beta A-subunit in this equine tissue is currently unknown, these results suggest that activin, but not inhibin, is predominantly produced in the endometrial glands of the pregnant mare, and thus produced activin may play a paracrine or endocrine role during pregnancy in this species.

Experimental infection of non-pregnant and pregnant sheep with Neospora caninum

In an initial experiment, 21 sheep in groups of five or six were inoculated subcutaneously (sc) with 10(8), 10(6) or 10(4) Neospora caninum tachyzoites (Liverpool isolate), or with control inoculum, and monitored for clinical signs and for "seroconversion". Animals given the two higher doses showed febrile responses and all three groups inoculated with the parasite showed seroconversion. In a second experiment, 12 pregnant sheep were each inoculated sc at 90 days' gestation with 10(6) tachyzoites, and at 25, 40 and 53 days post-inoculation (dpi) groups of four were killed for examination of the fetuses and placentas. Appropriate control ewes were included in the study. All fetuses were alive immediately before their dams were killed, except for one, which was found to be mummified at 40 dpi. Histopathological lesions were found consistently in both fetal central nervous system (CNS) and placental tissues. In the latter, focal necrosis, which was mild at 25 dpi, was much more severe at 40 dpi and much less severe at 53 dpi. Lesions in the fetal CNS consisted of focal microgliosis (with or without central necrosis), lymphoid cuffing and non-suppurative meningitis. Lesions were also found in fetal liver, heart and lung. Neospora antigen was demonstrated in fetal brain and placental tissues and, at 25 dpi, in single samples of fetal liver and heart. The prescapular lymph nodes did not differ in size from those of control fetuses but were more mature in that they contained a significantly greater number of secondary follicles. Both IgM and IgG antibodies to N. caninum were detected in the serum of fetuses from infected ewes. Thus, N. caninum readily infected pregnant ewes and caused lesions in fetal tissues and placentas which resembled those of ovine toxoplasmosis. In addition, the changes were similar to those of bovine neosporosis; the infected pregnant ewe therefore offers a good model for the bovine disease.

Plant immunomodulators for termination of unwanted pregnancy and for contraception and reproductive health.

Neem (Azadirachta indica) seed and leaf extracts have spermicidal, anti-microbial, anti-fungal and anti-viral properties. They are also immunomodulators that induce primarily a TH1 type response. These properties are being exploited to develop two different useful methods of fertility control. Neem extracts given orally at early post-implantation stage terminate pregnancy in rodents and primates. Treatment has no residual permanent effect and fertility is regained in subsequent cycles. The mechanism by which the action occurs is not fully clear. A transient increase in CD4 and more significantly in CD8 cells is noticed in mesenteric lymph nodes and spleen. A rise in immunoreactive and bioactive TNF-alpha and IFN-gamma in draining lymph nodes, serum and foetal-placental tissue is observed. A polyherbal cream and pessary have been developed containing three active ingredients of plant origin. These have synergistic spermicidal properties on human sperm as determined by the Sander Cramer test. Their use before mating has high contraceptive efficacy in rabbits and baboons. Another interesting property is their inhibitory action on a wide spectrum of micro-organisms, including Candida albicans, C. tropicalis, Neisseria gonorrhoeae, the multidrug-resistant Staphylococcus aureus and urinary tract Escherichia coli, Herpes simplex-2 and HIV-1. Phase I clinical trials have been completed in India, Egypt and the Dominican Republic, and indicate the safety of the formulation, its acceptability and beneficial action invaginosis due to infections.

The analysis of fatty acid content and phospholipase A2 activity in placenta of cows with and without retained fetal membranes.

The aim of the following study was the comparison of phospholipase A2 (PLA2) activity and fatty acids content in cows with and without retained fetal membranes. The activity of the enzyme and levels of fatty acids were measured in maternal and fetal placental tissues obtained from cows immediately after spontaneous parturition without (group A) and with (group B) retained fetal membranes. PLA2 activity was statistically significantly (P < 0.05) higher in group A than in group B, and was significantly lower in the fetal part than in the maternal part of placenta in both groups. The content of the examined fatty acids-myristic (14:0), palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linolenic (18:3), arachidic (20:0), arachidonic (20:4, AA)-was higher in group A than in B. Concentration of linoleic acid (18:2) showed the opposite relationship. There was a positive correlation between enzyme activity and content of det2ermined fatty acids. The results seem to confirm the bypothesis that the arachidonic acid pathway is altered in cases of retained placenta in cows.

Activity of placental glutathione peroxidase and superoxidedismutase in cows with and without retained fetal membranes

Changes in the levels of the activity of two enzymes that neutralize free radicals—glutathione peroxidase [(EC.1.11.1.9), GSH-Px] and superoxide dismutase—[(EC.1.15.1.1). SOD]-in cows with fetal membranes retention (RFM) were studied. The activities were measured in maternal and fetal placental tissues after spontaneous parturition without (group A) and with (group B) retained placenta. GSH-Px activities were higher in group B than in group A ( P<0.05). The activity of this enzyme was lower in the maternal than in the fetal part of the placenta in both groups. The activity of SOD was significantly ( P<0.05) lower in maternal part, and higher in fetal part, of placenta in group B compared with group A. Experiments on defence mechanisms against free radicals in periparturient cows in connection with more frequent sampling, prostaglandins levels, oxidative stress, nutrition and retained placenta are required to further elucidate the role of these enzymes.

Detection of fetal cells in transcervical samples and prenatal diagnosis of chromosomal abnormalities.

Transcervical samples collected by lavage, aspiration, and cytobrush from women between 6 and 13 weeks of gestation were tested for the presence of fetal cells using fluorescence in situ hybridization (FISH) with probes for chromosomes X, Y, 1, and 21, and by polymerase chain reaction (PCR) amplification of DNA sequences derived from chromosomes X, Y, and 21. With a few exceptions, a good correlation was observed between the results of sexing the fetuses using FISH or PCR on transcervical cell (TCC) samples retrieved by lavage and those obtained by testing fetal (placental) tissue. In a comparative study between TCC samples collected by lavage or cytobrush, the sex of the fetus was correctly diagnosed by PCR amplification of a Y-derived DNA sequence. Variable results were observed with samples obtained by aspiration, mainly because this procedure was found to be more prone to failure to remove thick mucus without previous injection of physiological saline. Chromosome 21-derived small tandem repeats (STRs) of fetal origin were successfully detected in about 40 per cent of TCC samples recovered by lavage. Two cases of chromosomal abnormalities, one of trisomy 21 and one of triploidy, were detected in TCC samples in the course of our investigations.