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PubMed2006

Mechanical analysis of chorion softening in prehatching stages of zebrafish embryos.

During early development, the chorion envelope of the zebrafish embryo undergoes a thinning process called "chorion softening," which has so far only been characterized chemically. In this study, a micromechanical force sensing system was used to characterize and quantitate mechanical modifications of the zebrafish embryo chorion during early development. Quantitative relationships between applied forces and chorion structural deformations were established at various embryonic stages. The measured penetration force into the chorion at the blastula stage was 1.3-fold greater than those at the prehatching stage. Furthermore, chorion elastic modulus values were determined by using a biomembrane elastic model. The elastic modulus of the chorion at the blastula stage was 1.66-fold greater than that at the prehatching stage, thus indicating that the chorion envelope become mechanically "softened" at the prehatching stage. The experimental results quantitatively describe "chorion softening," which is most likely due to proteolytic activities at the prehatching stage. Gradual chorion softening during embryonic development was also artificially achieved by treating blastula chorion with pronase, a proteolytic enzyme. The forces required to penetrate the pronase-treated chorion were similar to those at the prehatching stage. This similarity suggests that "chorion softening" may be induced by the release of protease from the embryos, and the chemical nature of the process involves proteolytic fragmentation of the ZP2 protein.

Animals↗
PubMed2006

Chorion type, birthweight discordance and tooth-size variability in Australian monozygotic twins.

Chorion type is an important variable that can affect the prenatal environment of monozygotic (MZ) twin pairs, leading to differences in growth and development. In particular, vascular anastomoses between monochorionic (MC) MZ twin pairs can lead to an imbalance in nutrition between co-twins. One objective of this study was to determine whether maternal reports, hospital records or birthweight discordances found in MZ co-twins provide reliable indications of monochorionicity. The other objective was to test the hypotheses that in MZ twin pairs of known chorion type, MC twin pairs would show greater birthweight differences and greater within-pair variability in permanent tooth size than dichorionic (DC) twin pairs, reflecting greater differences in intrauterine environment between MC MZ pairs. Birthweights and tooth size data were recorded for 170 pairs of MZ Australian twins enrolled in an ongoing study of dentofacial growth and development. Chorion type based on maternal reports was compared with that based on hospital records for a subsample of 68 pairs of these MZ twins. Maternal reports were found to be unreliable for determining chorion type and hospital records often did not provide enough information to be certain about chorionicity. For 27 twin pairs with confirmed chorion type, associations were tested between birthweight discordances in MZ twin pairs and chorion type, and also between intrapair variances for tooth size and chorion type. A significant association was noted between birthweight discordance and chorion type (p < .05), with greater discordances occurring more often in MC twin pairs. Although significant heterogeneity of intrapair variances for tooth size was found in only 5 of 48 comparisons, intrapair variances for crown dimensions were greater significantly more often in MC pairs than DC pairs (p < .05). Our findings indicated that neither maternal reports nor often hospital records can be relied upon for information on chorion type. However, when analyses were performed on data for MZ twin pairs of known chorion type, we found evidence of a significant association between intrapair birthweight differences and chorion type and also between intrapair variances of dental crown measurements and chorion type. Consistent with our hypotheses, large birthweight discordances were found to occur more often in MC twin pairs than DC twin pairs, and intrapair variances for tooth size in MC twin pairs exceeded those in DC twin pairs more often than expected due to chance.

Adult↗
PubMed1995

Comparison of transcervical and transabdominal chorionic villus sampling loss rates in nine thousand cases from a single center.

OBJECTIVES: Our purposes were (1) to compare the safety of transabdominal and transcervical chorionic villus sampling with the use of a consistent technique at one center and (2) to determine whether the training of fellows can be accomplished without an increase in the loss rate. STUDY DESIGN: We performed a retrospective comparison of transabdominal and transcervical chorionic villus sampling loss rates from procedures performed by three principal operators between 1984 and 1992. The type of procedure was chosen by the operator at the time of the procedure on the basis of placental location. RESULTS: Procedures 1 through 2573 were performed solely by transcervical chorionic villus sampling and had an overall fetal loss rate of 5.12%. With the addition of transabdominal chorionic villus sampling the overall fetal loss rate dropped to 3.07% (p < 0.0001). Three and one half years after the start of transabdominal chorionic villus sampling (about 1300 transabdominal chorionic villus sampling procedures), the transabdominal chorionic villus sampling loss rate was significantly better than the transcervical loss rate (p = 0.035), and the difference widened steadily after that. During the same time period seven fellows performed 716 procedures for a fetal loss rate among fellows of 2.72%. CONCLUSIONS: (1) Under optimal circumstances (one center, large numbers, few operators, consistent technique, operator choice of best approach), transabdominal chorionic villus sampling may be inherently safer than transcervical chorionic villus sampling. (2) The addition of transabdominal chorionic villus sampling decreases overall chorionic villus sampling loss rates. (3) Although the number of procedures performed by fellows is small, it appears that with close supervision by experienced operators successful training of fellows can be accomplished without adverse effects on loss rates.

Chi-Square Distribution↗
PubMed2004

Molecular characterization of a novel peroxidase involved in Aedes aegypti chorion protein crosslinking.

Peroxidase-catalyzed chorion or eggshell protein crosslinking is an important biochemical event contributing to the formation of a protective chorion or eggshell in insects. Although the survival of the developing or developed embryo in the environment before hatching relies on the protection of the chorion, the identity of the peroxidative enzyme responsible for mediating chorion protein crosslinking has never been identified in any insect species. In this report, we describe the determination of partial peptide sequences of a novel mosquito chorion peroxidase through LC/MS/MS of a trypsin-digested chorion peroxidase active fraction, specific localization of the enzyme in the chorion through histochemical analysis, proteolytic processing of chorion peroxidase through comparison of the accurate mass of its intact mature enzyme with molecular mass of its deduced amino acid sequence, isolation of its cDNA based on chorion peroxidase partial amino acid sequences, evaluation of its transcriptional profile in developing ovaries, and application of the primary mosquito chorion peroxidase sequence in predicting potential chorion peroxidases in other species.

Aedes↗
PubMed1993

Selecting human chorionic gonadotropin immunoassays: consideration of cross-reacting molecules in first-trimester pregnancy serum and urine.

OBJECTIVE: We investigated the variation in human chorionic gonadotropin results found with different commercial kits. Levels of human chorionic gonadotropin and related molecules were determined in pregnancy serum and urine and compared with the specificities of different laboratory, office, and home test kits. STUDY DESIGN: Total human chorionic gonadotropin (nicked+nonnicked), nonnicked human chorionic gonadotropin, free beta subunit, and beta core fragment were measured in 242 serum samples and 125 urine samples from early pregnancies. RESULTS: In serum, in the 2 weeks after the missed period when most pregnancy tests are performed, median levels of total, nonnicked, and beta human chorionic gonadotropin (total+free beta+beta core) were similar (< or = 12% difference). Individual values, however, varied significantly. For nonnicked human chorionic gonadotropin, values ranged from 41% to 145% and for beta from 101% to 145% of the total human chorionic gonadotropin level. In urine individual nonnicked values varied from < 1% to 148% and beta values from 102% to 547% of the total human chorionic gonadotropin level. A survey of 29 kits revealed that 10 were types detecting total human chorionic gonadotropin, five detecting nonnicked only, and 14 were beta assays. CONCLUSIONS: Results from total, nonnicked, and beta human chorionic gonadotropin kits are not necessarily interconvertible. Individual variations in levels of nicked human chorionic gonadotropin, free beta and beta core, and differences in their recognition by immunoassays causes discordant results.

Chorionic Gonadotropin↗
PubMed1987

Observations on the log human chorionic gonadotropin-time relationship in early pregnancy and its practical implications.

In this study, we examined whether the doubling time of human chorionic gonadotropin is different at different stages of early pregnancy and whether the use of multiple nomograms for doubling time of human chorionic gonadotropin rather than a single critical value can improve the diagnosis of ectopic pregnancy. Forty-four women with intrauterine pregnancies who had abdominal pain and/or vaginal bleeding but who did not abort their pregnancies and 44 women with surgically proved ectopic pregnancies were studied. No difference was found in the doubling time of human chorionic gonadotropin when women were classified according to recently published criteria (Pittaway DE, Reish RL, Wentz AC. Doubling times of human chorionic gonadotropin increase in early viable intrauterine pregnancies. Am J Obstet gynecol 1985;152:299-302), and estimates of the doubling time of human chorionic gonadotropin were not influenced by the initial human chorionic gonadotropin values or the sampling interval used. In the human chorionic gonadotropin range of practical interest, multiple nomograms identified 26 of 33 (79%) women with ectopic pregnancy who had rising levels of human chorionic gonadotropin, whereas our previously reported criteria identified 28 of 37 (76%) cases. The false positive rate for each method was 9.7%. Seventeen (19%) of 88 patients could not be allotted to the human chorionic gonadotropin categories for which nomograms of the doubling time of human chorionic gonadotropin have been derived. We conclude that our previous recommendations for determining the rate of increase of human chorionic gonadotropin in serum from paired samples do not require revision at this time.

Chorionic Gonadotropin↗
PubMed2003

Association between second-trimester isolated high maternal serum maternal serum human chorionic gonadotropin levels and obstetric complications in singleton and twin pregnancies.

OBJECTIVE: The purpose of this study was to examine the clinical significance of high maternal serum human chorionic gonadotropin levels in the second trimester in singleton and twin pregnancies within the Ontario maternal serum screening program. STUDY DESIGN: The study group comprised 564 women with singleton pregnancies with total maternal serum human chorionic gonadotropin levels of > or =4.0 multiples of the median (MoM) and serum marker alpha-fetoprotein levels of <2.0 MoM. The cases were matched with 1692 control subjects who had both serum marker alpha-fetoprotein levels and maternal serum human chorionic gonadotropin levels of <2.0 MoM. The second part of the study comprised 93 twin pregnancies with maternal serum human chorionic gonadotropin levels of > or =5.0 MoM and serum marker alpha-fetoprotein levels of <4.0 MoM; the control group (n = 1496) had serum marker alpha-fetoprotein levels of <4.0 MoM and maternal serum human chorionic gonadotropin levels of <5.0 MoM. The final part of the study included 25 women with extremely high maternal serum human chorionic gonadotropin levels (> or = 14;10 MoM). RESULTS: Of the singleton pregnancies with maternal serum human chorionic gonadotropin levels of > or = 14;4.0 MoM, 22.5% had severe adverse obstetric outcomes, compared with only 10.9% of the matched control population (P =.001). Women with markedly elevated maternal serum human chorionic gonadotropin levels had significantly increased risks of having spontaneous miscarriage, small-for-gestational-age infants, pregnancy-associated hypertensive disorder, and preterm delivery. Of the women with twin pregnancies with high maternal serum human chorionic gonadotropin levels (> or =5.0 MoM), 71% had at least one complication (such as miscarriage and preterm delivery) compared with 55.3% in the control group. Finally, 23 of 25 women with extremely high maternal serum human chorionic gonadotropin levels (> or = 14;10 MoM) had serious adverse outcomes (such as fetal abnormalities, pregnancy-associated hypertensive disorder, premature separation of placenta, intrauterine growth restriction, neonatal respiratory distress syndrome, and neonatal jaundice). CONCLUSION: Pregnancies with an elevated maternal serum human chorionic gonadotropin level are associated with adverse obstetric outcomes. Increased maternal and fetal surveillance is warranted in these pregnancies.

Case-Control Studies↗
PubMed1993

A subtle defect underlies altered lamellar orientation in the Gr16 chorion mutant of Bombyx mori.

Gr16 (chromosome 2, 6.9 cM) is a dominant, grey egg mutation of the domestic silkmoth, Bombyx mori, which produces an opaque instead of a translucent chorion. To determine the underlying cause of this defect, we examined the effects of the mutation on chorion ultrastructure, protein accumulation, and biosynthesis patterns, and on the restriction patterns of early chorion structural genes, using the presumed wild-type progenitor strain, Old European 16 (OE16), for comparison. Cross-sections of mature chorions examined by scanning electron microscopy showed that the inner lamellae were oriented perpendicular, rather than parallel, to the egg surface, with a smaller vertical zone bordered by normally oriented lamellae in the heterozygote, suggestive of codominant expression. This defect first appeared in transmission electron micrographs early in choriogenesis, probably during framework formation and/or expansion stages. Mature chorion protein patterns resolved by isoelectric focusing or two-dimensional polyacrylamide gel electrophoresis, synthetic profiles of virtually all chorion proteins following pulse-labeling with tritiated or [14C]glycine, and restriction patterns of early chorion genes examined by Southern blot hybridization were identical between mutant, wild-type, and heterozygote. These observations ruled out a major deletion of chorion structural genes or defects in the production and accumulation of normal chorion proteins as mechanisms underlying the mutation, unlike other putative Gr mutants mapping in its vicinity. The sole difference that we detected was a set of minor, early protein doublets of related size but differing isoelectric point, which showed reciprocal labeling intensities in Gr16 vs OE16 and were codominantly expressed. Preliminary pulse-chase experiments suggested that these proteins may be post-translationally modified forms which undergo differential processing in mutant and wild-type. Based on these observations, we postulate that the Gr16 mutation affects the primary structure of a minor, previously unidentified chorion or follicular cell component which is critical for determining lamellar orientation, and discuss models of how this might function.

Animals↗
PubMed1981

Improved human chorionic gonadotropin detection with carboxyl-terminal radioimmunoassay of the beta subunit on concentrated 24-hour urine in patients with testicular cancer.

The value of measuring serum levels of human chorionic gonadotropin in detecting and monitoring testicular cancer has been demonstrated convincingly. In this study the human chorionic gonadotropin was extracted by the kaolin-acetone procedure from 24-hour urine specimens and the total volume of the extract was adjusted to 15 ml. With a highly specific immunoassay system (H93) that recognizes the unique carboxyl-terminal peptide of human chorionic gonadotropin beta subunit (residue numbers 123 to 145) as described previously, the urinary human chorionic gonadotropin was measured serially in 32 patients of 15 patients with initially human chorionic gonadotropin-producing testicular tumors. These 15 patients had simultaneous measurements of serum human chorionic gonadotropin using an antiserum against the beta subunit (Sb6) and urinary human chorionic gonadotropin concentrates using H93 radioimmunoassay. The initial serum hormone levels of these 15 patients were elevated and returned to normal after therapy. However, despite this occurrence the urinary hormone levels also were elevated. The initial 5 patients with elevated urinary but normal serum human chorionic gonadotropin levels had recurrence. The use of this highly specific radioimmunoassay in measuring urinary human chorionic gonadotropin coupled with effective chemotherapeutic agents has been valuable in selecting patients in whom further therapy is warranted despite normal serum human chorionic gonadotropin and clinically undetectable tumor.

Adult↗
PubMed2002

The free beta-subunit of human chorionic gonadotropin as a prognostic factor in renal cell carcinoma.

The free beta-subunit of human chorionic gonadotropin beta is expressed in several nontrophoblastic tumours and this is usually associated with aggressive disease. Little is known about human chorionic gonadotropin beta expression in renal cancer. We determined the pretreatment levels of human chorionic gonadotropin beta in serum of patients with renal cell carcinoma, and studied whether elevated levels predicted the clinical outcome. Serum samples were collected before surgery from 177 patients with renal cell carcinoma and from 84 apparently healthy controls. Human chorionic gonadotropin beta in serum was measured by a highly sensitive time-resolved immunofluorometric assay. The prognostic value of human chorionic gonadotropin beta, and of usual clinical and pathological variables was analyzed by the Kaplan-Meier method, the log rank test and Cox multiple hazard regression. The serum concentrations of human chorionic gonadotropin beta were increased in 23% of the renal cell carcinoma patients and they were significantly higher in patients with renal cell carcinoma than in controls (P<0.0001). The concentrations did not correlate with clinical stage and histopathological grade, but patients with increased human chorionic gonadotropin beta levels had significantly shorter survival time than those with levels below the median (cut-off 1.2 pmol l(-1), P=0.0029). In multivariate analysis human chorionic gonadotropin beta, tumour stage and grade were independent prognostic variables. The serum concentration of human chorionic gonadotropin beta is an independent prognostic variable in renal cell carcinoma. The preoperative value of human chorionic gonadotropin beta in serum may be used to identify patents with increased risk of progressive disease.

Adult↗
PubMed2001

Chorion releases a factor that inhibits oxytocin-stimulated myometrial contractility in the pregnant guinea pig.

It was postulated that chorion releases a substance necessary for the maintenance of uterine quiescence during pregnancy. A decrease in the release of this substance at the end of the pregnancy would be necessary for normal myometrial activation. This hypothesis was tested by demonstrating the ability of chorion to inhibit oxytocin-stimulated myometrial contractility in vitro. Tissues were obtained from timed pregnant Duncan-Hartley guinea pigs either at pre-term or near-term gestation. Myometrial strips were placed in organ baths for isometric tension measurement and contractions stimulated by oxytocin (10(-8) mol/l). Fetal membranes or conditioned medium from chorion were added directly to the organ bath. Near-term chorion and chorion conditioned-medium decreased oxytocin-stimulated contractile activity to 39% and 49% respectively. Neither pre-term nor near-term amnion reduced oxytocin-stimulated myometrial contractile activity. Relaxation induced by pre-term chorion was greater than near-term chorion (23% and 41% of the oxytocin-induced basal level respectively; P < 0.05). Further, chorion-induced relaxation was independent of the gestational age of the myometrium. Human chorion from a term, not-in-labour woman also inhibited oxytocin-stimulated guinea pig myometrial contractility. It was concluded that the chorion releases a substance or substances that reduce oxytocin-stimulated myometrial contractility and may be involved in the maintenance of uterine quiescence during pregnancy.

Amnion↗
PubMed1997

Purification and partial characterization of 76 kDa transglutaminase in the egg envelope (chorion) of rainbow trout, Oncorhynchus mykiss.

Transglutaminase (TGase), responsible for crosslinking between proteins, is known to be localized exclusively in the egg envelope (chorion) of rainbow trout, Oncorhynchus mykiss, and probably participates in the post-fertilization chorion hardening. We purified the TGase from unfertilized egg chorions by sequential chromatography using SP-Sepharose, Q-Sepharose, and TSK-gel G3000SWXL columns. The purified enzyme was a monomeric protein having the molecular mass of 76 kDa. It promoted incorporation of monodansyl-cadaverine into chorion protein and catalyzed the polymerization of chorion subunit proteins. The effect of various reagents suggested that the chorion TGase is a Ca2+-dependent SH-enzyme similar to the well-characterized TGases of various animals. The highest activity was observed at pH 6.0. The amines examined in the present study inhibited the TGase activity of the purified enzyme. However, they did not necessarily cause effective inhibition of its activity. These properties of the chorion TGase were essentially consistent with our previous observations on polymerization of chorion proteins, resulting in chorion hardening. We compared the amino acid composition of the purified TGase with those of the previously characterized TGases of fishes, such as chum salmon and red sea bream. The results suggest that the chorion 76 kDa TGase is not homologous with those liver TGases in terms of amino acid composition.

Amino Acids↗
PubMed2006

Removal of the chorion before hatching results in increased movement and accelerated growth in rainbow trout (Oncorhynchus mykiss) embryos.

We investigated the effects of the chorion on movement and growth in rainbow trout (Oncorhynchus mykiss) embryos. To test if the chorion restricts movement and growth before hatching, we manually removed the chorion 3-6 days before the natural time of hatching (dechorionated) and compared movement, growth and oxygen consumption in dechorionated embryos and in embryos whose chorions remained intact until the time of hatching (chorionated). Dechorionated embryos exhibited 36 times more movement before hatching compared with intact embryos. By 10 h post-hatch there was no difference in the number of movements between the two groups. At the time of hatching [30 days post-fertilization (d.p.f.)], dechorionated embryos had a significantly greater embryonic body dry mass compared with chorionated embryos, which persisted up to 45 d.p.f. At first feeding (50 d.p.f.) there was no significant difference in embryonic body dry mass between the two groups. Dechorionated embryos had a significantly greater embryonic body protein content after hatching (32, 33 d.p.f.) compared with chorionated embryos. Despite the differences in movement and growth, there were no significant differences in oxygen consumption between chorionated and dechorionated embryos. Furthermore, there was no correlation between the number of movements and oxygen consumption in rainbow trout embryos (chorionated, dechorionated, and hatched). Taken together, the data indicate that rainbow trout embryos have the capacity to be relatively active before hatching, but that the chorion restricts or inhibits movement. Moreover, precocious activity in pre-hatch embryos is correlated with accelerated growth and higher protein content, suggesting that the exercise training effect observed in adult salmonids is also present in early developmental stages.

Animals↗
PubMed1995

Triple marker (alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin) versus alpha-fetoprotein plus free-beta subunit in second-trimester maternal serum screening for fetal Down syndrome: a prospective comparison study.

OBJECTIVE: Our purpose was to compare the efficacy of triple-marker screening (alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin) with alpha-fetoprotein plus free beta-human chorionic gonadotropin. STUDY DESIGN: Free beta-human chorionic gonadotropin was concurrently assayed in 2349 maternal serum samples. Trivariate and bivariate algorithms were used to calculate the risk for fetal Down syndrome by the two protocols. Free beta-human chorionic gonadotropin from 12 cases of fetal Down syndrome previously screened with the triple marker was retrospectively assayed. RESULTS: Mean maternal age of our study was 29.8 years (range 14 to 51 years). The initial screen-positive rate with the triple marker was 8.0% compared with 12.8% for alpha-fetoprotein plus free beta-human chorionic gonadotropin. All three cases of fetal Down syndrome ascertained in our prospective study were detected by the triple marker; in contrast, one of three was detected by alpha-fetoprotein plus free beta-human chorionic gonadotropin. By adding 12 additional cases of fetal Down syndrome, 12 of 15 (80%) were screen positive with triple marker and nine of 15 (60%) were screen positive with alpha-fetoprotein plus free beta-human chorionic gonadotropin. CONCLUSION: The detection rate of fetal Down syndrome was greater by use of a triple marker screen than when using alpha-fetoprotein plus free beta-human chorionic gonadotropin. Our data do not support the claims of other studies that suggest that alpha-fetoprotein plus free beta-human chorionic gonadotropin is superior to triple markers.

Adolescent↗
PubMed1999

First-trimester human chorionic villi express both immunoregulatory and inflammatory cytokines: a role for interleukin-10 in regulating the cytokine network of pregnancy.

PROBLEM: T-helper 2 (TH2)-type cytokines [i.e., interleukin (IL)-6, IL-10, and IL-13] and transforming growth factor (TGF)-beta are expressed by the murine decidua and/or placenta and are likely to suppress inflammatory cytokine [i.e., IL-2, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, IL-1 alpha, and IL-1 beta] production at the maternal-fetal interface. In addition, class I IFNs may protect the fetus from immunologic rejection and viral infections. This study examines the expression of inflammatory/immunoregulatory cytokines and IL-10 production by first-trimester chorionic villi. METHOD OF STUDY: Gestational tissues (n = 5) were obtained following elective terminations performed between 7 and 9 weeks of gestation. Chorionic villous tissues were separated from fetal membranes and decidua, and total RNA was extracted. Cytokine expression was assessed by a reverse transcriptase-polymerase chain reaction technique. Chorionic villi (n = 9; 6-12 weeks gestation) were maintained in organ culture, and human chorionic gonadotropin (hCG) and IL-10 levels were determined by immunoradiometric and enzyme-linked immunosorbent assays, respectively. RESULTS: IFN-gamma and IL-2 were generally not expressed by first-trimester chorionic villi. Low to moderate levels of expression were noted for IL-1 alpha, IL-1 beta, and TNF-alpha. High levels of mRNA were noted for IFN-alpha and IFN-beta, but IFN-tau was not expressed. In all tissues, TGF-beta 1 and IL-13 were either weakly expressed or not expressed. In contrast, moderate to high levels of IL-6 and IL-10 mRNA were detected in each chorionic villous sample. In chorionic villous explants obtained at 6-11 weeks gestation production of hCG and IL-10 was greatest during the first 24 hr ([hCG] = 6961 +/- 815 mIU/mL, [IL-10] = 92 +/- 11 pg/mL) and then declined through 72 hr. CONCLUSIONS: TH1-type cytokines (IL-2, IFN-gamma) are not expressed by first-trimester chorionic villous tissues: This is possibly due to local production of IL-10. In contrast, macrophage-associated cytokines (IL-1 beta and TNF-alpha) are expressed and their regulation may be critical for fetal survival. Finally, class 1 IFNs expressed by early chorionic tissues may protect the fetus from maternal rejection and viral transmission.

Abortion, Induced↗
PubMed1987

Predictive value of plasma human chorionic gonadotrophin beta subunit in diagnosing ectopic pregnancy after in vitro fertilisation and embryo transfer.

A study was conducted aimed at establishing a range of plasma concentrations of the beta subunit of human chorionic gonadotrophin that might predict ectopic pregnancy after in vitro fertilisation and embryo transfer. From May 1984 to February 1986, 161 consecutive pregnancies at the Monash University in vitro fertilisation unit were analysed by determining plasma beta human chorionic gonadotrophin concentrations between two and 10 weeks after oocyte collection. Eighty eight ongoing singleton pregnancies, 25 multiple pregnancies, 27 first trimester spontaneous abortions, 12 anembryonic pregnancies, and nine ectopic pregnancies resulted from these conception cycles. When compared with values for ongoing singleton pregnancies two weeks after oocyte collection plasma beta human chorionic gonadotrophin concentrations in ectopic pregnancies were significantly lower (p less than 0.05; Wilcoxon rank sum test). Two weeks after oocyte collection all plasma beta human chorionic gonadotrophin concentrations in the set of ectopic pregnancies were below 30.6 IU/l, which corresponded to the lower quartile (25th percentile) of beta human chorionic gonadotrophin concentrations in ongoing singleton pregnancies. The beta human chorionic gonadotrophin concentration corresponding to the lower quartile of ongoing singleton pregnancies at each week of gestation was used to derive the predictive value of various statistics in detecting ectopic pregnancy in patients after in vitro fertilisation. The sensitivity, specificity, predictive value of a positive result, predictive value of a negative result, and efficiency of a single plasma beta human chorionic gonadotrophin concentration in predicting ectopic pregnancy were 100%, 68.1%, 16.7%, 100%, and 70%, respectively, two weeks after oocyte collection. These results suggest that a single determination of the plasma beta human chorionic gonadotrophin concentration beginning 14 days after oocyte collection is clinically useful in predicting the outcome of pregnancy achieved by in vitro fertilisation. Ectopic pregnancy after in vitro fertilisation is more likely when beta human chorionic gonadotrophin concentration is below the lower quartile of values in ongoing singleton pregnancies achieved by the technique.

Chorionic Gonadotropin↗
PubMed2000

Chorion villus sampling versus amniocentesis for prenatal diagnosis.

BACKGROUND: Amniocentesis test results are usually available only after 18 weeks gestation. Chorion villus sampling (CVS) may be performed transabdominally or transvaginally, usually between 10 and 12 weeks gestation. OBJECTIVES: The objective of this review was to assess the safety and accuracy of chorion villus sampling compared to amniocentesis. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register. SELECTION CRITERIA: Randomised trials comparing first trimester chorion villus sampling and second trimester amniocentesis. DATA COLLECTION AND ANALYSIS: Trial quality was assessed. MAIN RESULTS: Three studies involving over 9000 women were included. The trials were generally of good quality. Compared to amniocentesis, chorion villus sampling was associated with more sampling and technical failures, and more false positive and false negative results. Pregnancy loss was more common after chorion villus sampling (odds ratio 1.33, 95% confidence interval 1.17 to 1.52). There is a suggestion (though not statistically significant) of an increase in stillbirths and neonatal deaths following chorion villus sampling. Maternal complications were uncommon. REVIEWER'S CONCLUSIONS: The increase in miscarriages after chorion villus sampling compared to amniocentesis appear to be procedure related. Second trimester amniocentesis appears to be safer than chorion villus sampling. The benefits of earlier diagnosis with chorion villus sampling must be set against the greater risk of pregnancy loss.

Chorionic Villi Sampling↗
PubMed1984

Regulation of the permeability of the medaka fish embryo chorion by exogeneous sodium and calcium ions.

We questioned if the optically transparent noncellular chorion, or egg envelope, which encapsulates the entire medaka fish (Oryzias latipes) embryo might in some way constitute a permeability barrier to high concentrations of the diuretic called amiloride. More specifically, we questioned if removal of cations from the exogenous environment of the medaka embryo might make the chorion more permeable to amiloride and thereby make the fish embryos more sensitive to the inhibitory and lethal effects of this drug. To test this question, chorion-encapsulated medaka embryos were exposed to: deionized-distilled water, to Yamamoto-Ringer's (Y-R) solution, to Yamamoto-Ringer's containing choline chloride as a substitute for NaCl, and to isotonic NaCl solution in the presence of and in the absence of amiloride. Briefly, the prediction that the medaka embryos would be most sensitive to amiloride's inhibitory effects in distilled water was confirmed. Further studies showed that the presence of Na+ or of Ca2+ alone in the culture solution gave partial protection against the lethal effects of the amiloride. Electron probe X-ray microanalysis studies indicated that addition of Ca2+ and other cations to the culture solution caused the concentrations of cations to increase in the chorion, and that increase was correlated to a visible decrease in the permeability of the chorion to the amiloride. This decreased permeability of the chorion apparently protected the embryo from the amiloride. The decreased permeability of the chorion to amiloride, which occurred in the presence of the cations present in Y-R solution, was found to be reversible once the cations were washed from the chorion. Key words medaka, chorion, Na+, Ca2+ permeability, x-ray microanalysis, Oryzias latipes, egg envelope.

Amiloride↗