The relationships between fetal and maternal placental blood flows.

Individual maternal and fetal flows to 706 placental cotyledons obtained from 9 chronically catheterized pregnant ewes and their fetuses (gestation age 123-141 days) were measured. The larger the cotyledon the greater the maternal and fetal blood flow to it. Both fetal and maternal flows to larger cotyledons, however, tended to be lower when corrected for the weight of the cotyledon perfused. Changes in fetal placental flow (dfgc, ml/min/g) occurring within 15 min of administration of 15 mg i.v. of captopril to the ewe were dependent on changes in fetal placental vascular resistance (dcotfr) and maternal flow (dmgc) according to the equation dfgc = 0.123 + 0.185 dmgc - 0.026 dcotfr. Changes in maternal placental flow occurring within 15 min of administration of 15 mg i.v. of captopril to the ewe were dependent on changes in maternal placental vascular resistance (dcotmr) and changes in fetal flow according to the equation dmgc = 0.483 + 0.496 dfgc - 0.0198 dcotmr. The changes in fetal flow over the next 1.5h of treatment with captopril at 6 mg/h were dependent on neither changes in fetal placental vascular resistance nor maternal placental flow. changes in maternal placental flows over the same time were no longer related to changes in fetal flow and depended only to a minimal extent on changes in maternal placental resistance. These analyses suggest that treatment of the pregnant ewe with captopril may have disturbed the normal relationships between maternal and fetal placental circulations.     

On the distinction between chromosomes No. 21 and No. 22 by the C-banding pattern

Summary Chromosome No. 21 consistently shows a lighter C band at the centromere than chromosome No. 22, allowing reliable differentiation. This distinction was demonstrated in karyotypes with centric fusions t(Dq 21q), trisomy 21 and by comparing the C-and Q-band polymorphism of the short arms of the G chromosomes.

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Zusammenfassung Chromosom 21 weist stets eine schwächere C-Bande am Zentromer auf als Chromosom 22, wodurch diese Chromosomen eindeutig unterscheidbar sind. Belegt wird dieser Befund durch Karyotypen mit zentrischer Fusion t(Dq21q), Trisomie 21, und durch einen Vergleich des C-und Q-Banden-Polymorphismus der kurzen Arme.

     

Detection of Y STR markers of male fetal dna in maternal circulation

BACKGROUND:

Circulating fetal cells and cell free DNA in the maternal blood has been shown to help in prenatal diagnosis of genetic disorders without relying on invasive procedures leading to significant risk of pregnancy loss.

AIM:

The current study was undertaken to detect the male fetal population using Y STR markers DYS 19, DYS 385 and DYS 392 and also to study the extent of persistence of fetal DNA in the mother following delivery.

MATERIALS AND METHODS:

Blinded study was conducted on 50 mothers delivering male and female babies. Cellular and cell free DNA was extracted from maternal and fetal cord blood and amplified for Y STR markers by PCR.

RESULTS:

The amplification sensitivity of Y specific STR, DYS19 was 100% (22/22) in the male fetal DNA samples. The incidence of other STRs, i.e., DYS385 and DYS392 were 91% (20/22) each. Analysis of results revealed that thirteen of the twenty six women had detectable male fetal DNA at the time of delivery. However fetal DNA was not detectable twenty four hours after delivery.

CONCLUSION:

Preliminary results show that the separation of fetal cell-free DNA in the maternal circulation is a good low-cost approach for the future development of novel strategies to provide non-invasive techniques for early prenatal diagnosis.     

Correlation between maternal inflammatory markers and fetomaternal adiposity

Outside pregnancy, both obesity and diabetes mellitus are associated with changes in inflammatory cytokines. Obesity in pregnancy may be complicated by gestational diabetes mellitus (GDM) and/or fetal macrosomia. The objective of this study was to determine the correlation between maternal cytokines and fetomaternal adiposity in the third trimester in women where the important confounding variable GDM had been excluded. Healthy women with a singleton pregnancy and a normal glucose tolerance test at 28weeks gestation were enrolled at their convenience. Maternal cytokines were measured at 28 and 37weeks gestation. Maternal adiposity was assessed indirectly by calculating the Body Mass Index (BMI), and directly by bioelectrical impedance analysis. Fetal adiposity was assessed by ultrasound measurement of fetal soft tissue markers and by birthweight at delivery. Of the 71 women studied, the mean maternal age and BMI were 29.1years and 29.2kg/m(2) respectively. Of the women studied 32 (45%) were obese. Of the cytokines, only maternal IL-6 and IL-8 correlated with maternal adiposity. Maternal TNF-α, IL-β, IL-6 and IL-8 levels did not correlate with either fetal body adiposity or birthweight. In this well characterised cohort of pregnant non-diabetic women in the third trimester of pregnancy we found that circulating maternal cytokines are associated with maternal adiposity but not with fetal adiposity.     

The distinction between transudates and exudates

Summary The first step in the diagnosis of pleural effusions is the distinction between exudates and transudates. The aim of this study was to evaluate the usefulness of various parameters for the differentiation of pleural exudates and transudates. We recorded clinical characteristics, final diagnoses, and measured pleural fluid and serum levels of albumin, protein, LDH, cholesterol, and bilirubin of 381 consecutive patients with pleural effusion. Seventy-one (23%) pleural effusions were transudates and 236 were exudates. As a single criterion, the pleural fluid to serum albumin ratio >0.5 was the most accurate parameter (88.4%). An albumin gradient of 12 g/l had an accuracy of 75% in the whole population but it detected 96% of transudative effusions in patients treated with diuretics. Light’s criteria and abbreviated Light’s criteria had similar accuracies, 87.8% vs. 88.2%, respectively. In conclusions, different alternatives can be used instead of Light’s criteria.     

Comparison of bone metabolic markers between maternal and cord blood

We studied 41 normal pregnant women and their neonates in order to compare bone metabolism between them. We examined more specific bone formation markers (intact osteocalcin, bone-specific alkaline phosphatase) and a recently developed and more sensitive bone resorption marker (C-telopeptide of type I collagen; CTX) than previously available in maternal and umbilical cord venous blood taken at delivery. The concentrations of all markers of bone turnover, including CTX, in cord serum were significantly higher than those in maternal serum. There was no significant correlation between maternal and cord serum levels for any marker. These results indicate that fetal bone turnover is markedly enhanced compared with maternal bone turnover and is independent of maternal bone metabolism in late pregnancy.     

Interactions between trophoblast cells and the maternal and fetal circulation in the mouse placenta

Mammalian embryos have an intimate relationship with their mothers, particularly with the placental vasculature from which embryos obtain nutrients essential for growth. It is an interesting vascular bed because maternal vessel number and diameter change dramatically during gestation and, in rodents and primates, the terminal blood space becomes lined by placental trophoblast cells rather than endothelial cells. Molecular genetic studies in mice aimed at identifying potential regulators of these processes have been hampered by lack of understanding of the anatomy of the vascular spaces in the placenta and the general nature of maternal-fetal vascular interactions. To address this problem, we examined the anatomy of the mouse placenta by preparing plastic vascular casts and serial histological sections of implantation sites from embryonic day (E) 10.5 to term. We found that each radial artery carrying maternal blood into the uterus branched into 5-10 dilated spiral arteries located within the metrial triangle, populated by uterine natural killer (uNK) cells, and the decidua basalis. The endothelial-lined spiral arteries converged together at the trophoblast giant cell layer and emptied into a few straight, trophoblast-lined "canals" that carried maternal blood to the base of the placenta. Maternal blood then percolated back through the intervillous space of the labyrinth toward the maternal side of the placenta in a direction that is countercurrent to the direction of the fetal capillary blood flow. Trophoblast cells were found invading the uterus in two patterns. Large cells that expressed the trophoblast giant cell-specific gene Plf (encoding Proliferin) invaded during the early postimplantation period in a pattern tightly associated with spiral arteries. These peri/endovascular trophoblast were detected only approximately 150-300 microm upstream of the main giant cell layer. A second type of widespread interstitial invasion in the decidua basalis by glycogen trophoblast cells was detected after E12.5. These cells did not express Plf, but rather expressed the spongiotrophoblast-specific gene Tpbp. Dilation of the spiral arteries was obvious between E10.5 and E14.5 and was associated with a lack of elastic lamina and smooth muscle cells. These features were apparent even in the metrial triangle, a site far away from the invading trophoblast cells. By contrast, the transition from endothelium-lined artery to trophoblast-lined (hemochorial) blood space was associated with trophoblast giant cells. Moreover, the shaping of the maternal blood spaces within the labyrinth was dependent on chorioallantoic morphogenesis and therefore disrupted in Gcm1 mutants. These studies provide important insights into how the fetoplacental unit interacts with the maternal intrauterine vascular system during pregnancy in mice.     

The relationship between maternal and fetal plasma protein binding of methadone in the ewe during the third trimester

The binding of methadone to maternal and fetal plasma proteins was determined throughout the third trimester in the pregnant ewe. Blood was sampled from chronic indwelling catheters placed in the maternal aorta and fetal aorta. Methadone binding was determined by use of equilibrium dialysis with (³H)-methadone. Maternal binding ranged from 50.4 to 89.5%, with a mean of 76.2 ±1.3 (SE)%. Fetal binding was initially significantly lower than maternal binding, but increased rapidly in the last two weeks before parturition. Prior to 130 days gestation, the ratio of fetal binding to maternal binding was 0.40 ± 0.03. This binding ratio increased to 0.82 ± 0.08 in the last few days of pregnancy. Preliminary results suggested that maternal binding was higher in the early post-partum period. These results demonstrate that the relationship between maternal and fetal plasma binding of methadone changes rapidly towards the end of pregnancy, and fetal binding approaches maternal binding at parturition.