Effect of prenatally and postnatally induced hypoxia on blood volume of newborn lambs

The effect of both prenatally and postnatally induced acute hypoxia on the blood volume was studied in 16 newborn lambs. Hypoxia was induced by 8% O₂ inhalation for 10–20 minutes prenatally in 7 term pregnant ewes immediately before caesarean section delivery of the lambs (Group 1), and postnatally in nine 2–4 day old lambs born spontaneously (Group 11). The umbilical cords of Group 1 lambs were clamped early (E.C.) within 10 seconds after birth. Group 11 lambs had their cords severed within one minute of birth by the ewes. Blood volume (BV) was measured by the double label, radioiodinated human serum albumin-125 (RIHSA-125) plasma tag and radiochromium-51 (Cr⁵¹) red cell tag dilution technique. The red cell volume (RCV), which reflects the size of placental transfusion best, is significantly higher in Group 1 (42.1 ± 1.6 ml/kg) than in normal E.C. lambs (29.8 ± 2.0 ml/kg). The RCV in Group 1 was smaller than that in late clamped (L.C.) lambs, in whom an almost complete placental transfusion (RCV = 50.4 ± 2.3 ml/kg) had occurred; and close to those of spontaneously born lambs (S.B.) who received a partial placental transfusion (RCV = 36.7 ± 2.1 ml/kg). This finding in Group 1 suggests that with prenatal hypoxia, a partial placental transfusion had occurred in utero. In Group 11 lambs in whom hypoxia was postnatally induced, the BV, RCV, and plasma volume (109.7 ± 5.2, 44.1 ± 1.7 and 65.1 ± 4.2 ml/kg) were slightly, but not significantly, increased from control values of 101.6 ± 4.9, 40.8 ± 1.7 and 60.8 ± 4.3 mg/kg), respectively. It is suggested that postnatally induced hypoxia does not significantly increase the blood volume of newborn lambs due to the absence of placental reservoir of blood. Prenatally induced hypoxia appeared to bring about a higher blood volume than expected in E.C. lambs due to a transfer of placental blood to the fetus in utero. Blood volume redistribution in the feto-placental unit in utero is an unique adaptational response to prenatal hypoxia.     

Treatment of pregnant BALB/c mice with sulphadoxine pyrimethamine or chloroquine abrogates Plasmodium berghei induced placental pathology

Malaria infection during pregnancy is a risk factor for foetus survival and is associated with abortion, premature delivery and low birth weight of infants in malaria endemic regions. In these regions, prophylactic measures and treatment mainly rely on chloroquine and sulphadoxine pyrimethamine, but their efficacy in reducing the placental pathology has not been studied. Therefore, the present study was designed to assess the effectiveness of chloroquine and sulphadoxine pyrimethamine treatment in reducing the placental pathology of Plasmodium berghei infected BALB/c mice. It was observed that pregnant-infected mice, treated either with chloroquine or sulphadoxine pyrimethamine had significantly lower percent parasitaemia, 100% survival and delivered normally compared with untreated pregnant-infected mice. Interestingly, antimalarial treatment significantly reduced malondialdehyde (MDA) levels, measure of lipid peroxidation and number of apoptotic cells in the placentae of pregnant-infected treated mice. Histologically also no morphological and cellular alterations were observed in the placentae of pregnant-infected treated mice. Taken together, the study shows the effectiveness of chloroquine and sulphadoxine pyrimethamine treatment, when administered in second trimester in abrogating malaria induced oxidative stress, apoptosis and histopathological alterations in the placenta, leading to normal foetal development.     

Pre-parturition profile of steroids and prostaglandin in cows with or without foetal membrane retention

Retained foetal membranes in cattle is one of the most common complications associated to the reduction in milk yield and impaired fertility in dairy cattle. In order to determine some endocrine mechanisms controlling parturition and delivery of foetal membranes, plasma concentrations of steroids and prostanoids were determined in 20 healthy Holstein cows. Samples were taken within the interval of 5 days pre-parturition to 12h after calving. Progesterone (P4) levels were similar in cows with (PR) and without (NPR) placental retention. While the estradiol-17beta (E2) peak at parturition was lower in PR than in NPR cows, cortisol levels were greater in PR cows 12 and 24h pre-parturition. The Prostaglandin F2alpha metabolite (PGFM) levels were higher at parturition in NPR compared with the PR group, but 12h later, these levels in the PR group increased so that concentrations were greater as compared with NPR cows. The Prostaglandin E2 metabolite (PGEM), 24, 48 and 72 h pre-parturition, were higher in PR cows. However, the PGFM:PGEM ratio was greater in cows up NPR at all time when included, indicating the importance of higher levels of Prostaglandin F2alpha (PGF2alpha) than Prostaglandin E2 (PGE2) for normal placental delivery. In conclusion, placental retention was related to both estrogen and PGF2alpha deficiency, which may be a consequence of metabolic stress leading to PGE2 and maternal cortisol synthesis before parturition.     

Breed, litter and parity effects on placental weight and placentome number, and consequences for the neonatal behaviour of the lamb

Lamb survival is impaired in low birth weight lambs, and those that are slow to stand and suck. Many of the factors that influence lamb vigour, such as parity, litter size, and breed, may exert their effects, at least partially, before birth by influencing placenta development. Our hypothesis was that retarded lamb behavioural development was due to differences in placentation in these animals. Data were collected from Blackface and Suffolk lambs in the first 2 h after birth and placentas were collected when delivered. Suffolk lambs, which were behaviourally slower and had lower rectal temperatures than Blackface lambs, were associated with larger but less efficient placentas (placental efficiency defined as foetal weight supported per g placenta) with fewer foetal cotyledons than Blackface placentas. Triplet lambs were significantly slower than twin or single lambs to suck and had lower rectal temperatures. Although placenta efficiency increased with litter size, placenta and cotyledon weight, and cotyledon number increased with twinning but not thereafter. It seemed likely that triplet lambs suffered some placental insufficiency in comparison to other litter sizes. Lambs born to first parity mothers were slower to stand and reach the udder than lambs of more experienced ewes, and first parity ewes also had smaller and less efficient placentas although cotyledon number was not affected. Male lambs tended to be slower than female lambs for most behaviours, although rectal temperatures were not affected. The sire of the lamb also influenced lamb behaviour and rectal temperature. Both lamb sex and lamb sire influenced the average weight of placental cotyledons, thus some of the sire effect on the behaviour and birth weight of his progeny might be mediated through placental development. Lamb neonatal vigour was correlated with placental efficiency suggesting that lamb behaviour immediately after birth is related to placental development and function.     

Unilateral Ischemia of the Fused Twin Placenta: A Manifestation of the Twin Transfusion Syndrome?

Two cases of multiple births were observed in which a twin placenta showed a striking gross and microscopic ischemia of one of its fused components. In both cases death of one or more of the infants occurred. Case 1 was a triplet birth of identical siblings and two of the infants died on the second and third days after birth, respectively. Case 2 was a twin birth in which one of the infants was stillborn. Two other cases are quoted from the literature in which a similar pallor of one-half of the twin placenta was observed, and both these cases were also associated with death of the associated fetus.It is possible that this placental lesion may be due to transfusion of blood from one placental half to the other (twin transfusion syndrome) with harmful effects on one or both fetuses.     

Ultrastructural changes in the placenta of the ewe following foetal infusion of cortisol.

The placental changes which followed continuous infusion of cortisol into the sheep foetus in the later stages of gestation were, like the hormonal changes, broadly similar to those of spontaneous parturition. There was, however, a premature separation of foetal and maternal tissues in certain areas of the placental cotyledons, and this separation appeared to protect the foetal epithelium from the degenerative changes which normally take place in the short space of time between the birth of the lamb and the delivery of the foetal membranes. The results suggest that an experimental model in which premature labour is induced by the administration of cortisol to the foetus is probably incomplete, and that additional factors almost certainly contribute to the cascade phenomenon of spontaneous parturition.     

Twin-to-twin transfusion syndrome: a case report. Antepartum prediction of underlying placental vascular pattern in monochorionic twin pregnancies may be possible.

A case of twin-to-twin transfusion syndrome is described. Comparing data of serial antepartum ultrasonography with a haemodynamic model suggests the possibility of predicting the underlying placental vascular anatomy. It is suggested that serial ultrasonography, including full biometry, pulsatility indices of the umbilical arteries, foetal echocardiography, assessment of amniotic fluid indices and foetal bladder filling could serve as ultrasound parameters for pattern recognition of the underlying placental vascular anomaly. Biometry should be plotted serially in a difference/average plot. Future application of such intensive ultrasound monitoring in monochorionic twins, as soon as monochorionicity is established, may distinguish those monochorionic twins who may benefit from treatment from those whom it would be better only to observe.     

Immunological Aspects of Intrauterine Transfusion

Two cases of intrauterine transfusion were studied with reference to the viability and fate of donor lymphocytes. In one of the infants donor lymphocytes were found in cord blood in significant numbers, suggesting the presence of a degree of immunological tolerance. Though lymphocyte chimerism may occur after foetal transfusion, the absence of associated graft-versus-host reactions in the great majority of babies so treated implies that an immunological protection mechanism develops by at least the second half of gestation.Cord serum immunoglobulins were normal in both cases except for the presence of IgA, presumably due to the passive transfer of donor protein.The opportunity afforded by intrauterine transfusion for the study of foetal immunology is stressed. It is suggested that, in our present state of knowledge and in view of the small risk of graft-versus-host reaction, such studies should have precedence over efforts to remove immunologically active cells and protein from transfusion blood, especially since such efforts may impair the efficacy of the procedure.     

Effect of prior eradication of Plasmodium berghei infection on the foetal development and parasitaemic levels under the stress of pregnancy

Pregnant mice infected on gestation day (GD) 13 with Plasmodium berghei had similar rate of parasitaemia and mortality as non pregnant controls. 50% of pregnant infected mice had normal delivery, 20% had absorbed foetuses and 30% died before parturation. However, animals infected with P. berghei, treated with drugs (sulfadiazine or chloroquine) had normal foetal development. No recrudescence occurred in either of these groups of animals even under the stress of pregnancy indicating protection. Pups born to pregnant infected mice (GD) 13 had low body weight as compared to pups born to mice which were infected and treated with drugs. Histopathological findings showed hyperplasia of trophoblast and plugging of placental sinusoids with parasitized erythrocytes in animals infected on GD 13 only. It is felt that prior eradication of malaria infection results in development of sufficient immunity which prevents the mal development of foetuses or parasitaemic levels under the stress of pregnancy.     

Amniotic fluid and hemodynamic model in monochorionic twin pregnancies and twin-twin transfusion syndrome

We developed a mathematical model of monochorionic twin pregnancies and twin-twin transfusion syndrome (TTTS), combining both fetal fluid dynamics and fetoplacental growth and circulation alterations and assuming that transplacental fluid flow from mother to fetus accounts for normal fetal and amniotic fluid volumes. Ten coupled differential equations, describing fetal total body and amniotic fluid volumes, their osmolalities, and fetal blood colloid osmotic pressure, for both donor and recipient twins, were solved numerically. Amniotic flows are controlled by fetal plasma osmolality and hydrostatic and colloid osmotic pressures. We included varying placental anastomoses and placental sharing of the circulations. Consistent with clinical experience, model predictions are: fetofetal transfusion from unidirectional arteriovenous anastomoses cause oligo-polyhydramnios, a normal size recipient but hypovolemic donor; compensating oppositely directed deep and superficial anastomoses moderate discordant development; and anhydramnios results from mild and severe TTTS, where milder forms may even present earlier in gestation than severe TTTS. Unequal placental circulatory sharing may exacerbate discordant development. In conclusion, our model simulates a wide variety of realistic manifestations of amniotic fluid volume and fetal growth in TTTS related to placental angioarchitecture. The model may allow an assessment of the efficacy of current therapeutic interventions for TTTS.     

Foetal and placental growth in the mouse after pre-implantation development in vitro under oxygen concentrations of 5 and 20%

Blastocysts which developed from two-cell mouse embryos in culture tubes containing an atmosphere with 20% oxygen had approximately 20% fewer blastomeres than blastocysts which developed under an oxygen concentration of 5%. When these smaller blastocysts were transferred to the uteri of pseudopregnant foster mothers, the foetuses developing were as viable as those developing from blastocysts cultured under 5% oxygen, indicating their ability to regulate for a lower blastomere number by at least day 17 of development. The transfer operation itself had no adverse effect on foetal or placental growth. However, culture of blastocysts in vitro did depress foetal though not placental growth, suggesting that the inner cell mass is more susceptible than the trophectoderm to culture in vitro. Foetal but not placental growth was lower following the transfer of blastocysts to a day-3 rather than a day-4 uterus. Four cases of placental fusion were found. In one case, the foetuses were contained within the same embryonic sac and may have been twins.     

Maternal–foetal genomic conflict and speciation: no evidence for hybrid placental dysplasia in crosses between two house mouse subspecies

Interspecific hybridization between closely related mammalian species, including various species of the genus Mus, is commonly associated with abnormal growth of the placenta and hybrid foetuses, a phenomenon known as hybrid placental dysplasia (HPD). The role of HPD in speciation is anticipated but still poorly understood. Here, we studied placental and foetal growth in F₁ crosses between four inbred mouse strains derived from two house mouse subspecies, Mus musculus musculus and Mus musculus domesticus. These subspecies are in the early stage of speciation and still hybridize in nature. In accordance with the maternal–foetal genomic conflict hypothesis, we found different parental influences on placental and foetal development, with placental weight most affected by the father's body weight and foetal weight by the mother's body weight. After removing the effects of parents’ body weight, we did not find any significant differences in foetal or placental weights between intra‐subspecific and inter‐subspecific F₁ crosses. Nevertheless, we found that the variability in placental weight in inter‐subspecific crosses is linked to the X chromosome, similarly as for HPD in interspecific mouse crosses. Our results suggest that maternal–foetal genomic conflict occurs in the house mouse system, but has not yet diverged sufficiently to cause abnormalities in placental and foetal growth in inter‐subspecific crosses. HPD is thus unlikely to contribute to speciation in the house mouse system. However, we cannot rule out that it might have contributed to other speciation events in the genus Mus, where differences in the levels of polyandry exist between the species.     

Stimulation of interstitial cell growth after selective destruction of foetal Leydig cells in the testis of postnatal rats

Summary Five-day-old male rats received a single treatment of ethane dimethanesulphonate (EDS), and the response of the testis on days 6–10 and 21 was examined by light microscopy and morphometry, supplemented by measurement of peripheral testosterone levels. One day after treatment, foetal Leydig cells degenerated, showing fragmentation, condensation and nuclear pyknosis. Macrophages phagocytosed the foetal Leydig cells resulting in their disappearance by day 7. Destruction of foetal Leydig cells was followed by an arrest of testicular growth in comparison to testes of intact age-matched control rats. In testes of EDS-treated rats, gonocytes and spermatogonia also degenerated, forming pyknotic bodies within the seminiferous cords. In contrast, interstitial fibroblasts and mesenchymal cells showed proliferative activity, which on days 4 and 5 after treatment resulted in peritubular hyperplasia surrounding each seminiferous cord. Thereafter, on day 21 after EDS administration, the previously depressed serum testosterone levels became markedly elevated coincident with the development of many immature-type Leydig cells, of which the total volume per testis was similar to that of Leydig cells in control testes, despite a four- to five-fold difference in testicular volumes. The results indicate that, although EDS destroys the foetal Leydig cells and impairs spermatogenesis, the interstitial tissue exhibits increased cell growth. The latter probably occurs in response to altered gonadotrophic stimulation and/or disturbances in the interaction between the seminiferous cords and the interstitial tissue.     

Placental transfer of stobadine in rabbits

Stobadine, a pyridoindole antioxidant, was investigated for its placental transfer and distribution in New Zealand white rabbits on the 27th day of gestation. The concentrations of stobadine were determined in maternal and foetal organs (plasma, brain, heart) at 30, 60, 120, and 360 minutes after oral administration of the drug in a dose of 5 mg/kg. The results obtained proved that after oral stobadine intake by rabbits at the stage of advanced pregnancy both maternal and foetal organs were under a certain drug level which could act protectively against oxidative stress--frequently occurring during late organogenesis, foetal stages and delivery, as well as during early postnatal development.     

IFN-gamma and IL-10 mediate parasite-specific immune responses of cord blood cells induced by pregnancy-associated Plasmodium falciparum malaria

Available evidence suggests that immune cells from neonates born to mothers with placental Plasmodium falciparum (Pf) infection are sensitized to parasite Ag in utero but have reduced ability to generate protective Th1 responses. In this study, we detected Pf Ag-specific IFN-gamma(+) T cells in cord blood from human neonates whose mothers had received treatment for malaria or who had active placental Pf infection at delivery, with responses being significantly reduced in the latter group. Active placental malaria at delivery was also associated with reduced expression of monocyte MHC class I and II in vivo and following short term in vitro coculture with Pf Ag compared with levels seen in neonates whose mothers had received treatment during pregnancy. Given that APC activation and Th1 responses are driven in part by IFN-gamma and down-regulated by IL-10, we examined the role of these cytokines in modulating the Pf Ag-specific immune responses in cord blood samples. Exogenous recombinant human IFN-gamma and neutralizing anti-human IL-10 enhanced T cell IFN-gamma production, whereas recombinant human IFN-gamma also restored MHC class I and II expression on monocytes from cord blood mononuclear cells cocultured with Pf Ag. Accordingly, active placental malaria at delivery was associated with increased frequencies of Pf Ag-specific IL-10(+)CD4(+) T cells in cord blood mononuclear cell cultures from these neonates. Generation and maintenance of IL-10(+) T cells in utero may thus contribute to suppression of APC function and Pf Ag-induced Th1 responses in newborns born to mothers with placental malaria at delivery, which may increase susceptibility to infection later in life.     

Placental Lactogen Levels as Guide to Outcome of Threatened Abortion

The clinical value has been assessed of circulating placental lactogen levels as a pointer to the outcome in a patient with vaginal bleeding in early pregnancy. By using a semiautomated radioimmunoassay the normal range of values for the first and second trimesters has been established. In patients admitted with vaginal bleeding after the eighth week of gestation estimation of plasma human placental lactogen showed that patients with low levels were those in whom the abortion was completed during the first admission. Women whose pregnancies continued normally or who aborted after their first discharge from hospital had normal levels. In a small group sampled before the onset of bleeding but who later aborted the mean levels were lower than normal. This simple and inexpensive test can indicate those women in whom abortion is inevitable and could be used to reduce substantially the length of hospital stay in this common complication of early pregnancy.     

Characterization of human foetal intestinal alkaline phosphatase. Comparison with the isoenzymes from the adult intestine and human tumour cell lines.

The molecular structure of human foetal intestinal alkaline phosphatase was defined by high-resolution two-dimensional polyacrylamide-gel electrophoresis and amino acid inhibition studies. Comparison was made with the adult form of intestinal alkaline phosphatase, as well as with alkaline phosphatases isolated from cultured foetal amnion cells (FL) and a human tumour cell line (KB). Two non-identical subunits were isolated from the foetal intestinal isoenzyme, one having same molecular weight and isoelectric point as placental alkaline phosphatase, and the other corresponding to a glycosylated subunit of the adult intestinal enzyme. The FL-cell and KB-cell alkaline phosphatases were also found to contain two subunits similar to those of the foetal intestinal isoenzyme. Characterization of neuraminidase digests of the non-placental subunit showed it to be indistinguishable from the subunits of the adult intestinal isoenzyme. This implies that no new phosphatase structural gene is involved in the transition from the expression of foetal to adult intestinal alkaline phosphatase, but that the molecular changes involve suppression of the placental subunit and loss of neuraminic acid from the non-placental subunit. Enzyme-inhibition studies demonstrated an intermediate response to the inhibitors tested for the foetal intestinal, FL-cell and KB-cell isoenzymes when compared with the placental, adult intestinal and liver forms. This result is consistent with the mixed-subunit structure observed for the former set of isoenzymes. In summary, this study has defined the molecular subunit structure of the foetal intestinal form of alkaline phosphatase and has demonstrated its expression in a human tumour cell line.     

MANAGEMENT OF ERYTHROBLASTOSIS FETALIS

The practical management of the problem of erythroblastosis depends primarily on the prenatal determination of which pregnancies might result in an erythroblastotic infant. The physician primarily concerned with the care of the child must attend the delivery of every Rh-negative woman whose serum contains anti-Rh antibodies. At present, prompt confirmation of the suspected diagnosis immediately following birth and immediate exchange transfusion in infants with laboratory or clinical evidence of the disease are necessary to reduce morbidity and prevent kernicterus.     

Placental transfusion in the naturally born lamb

Neonatal blood volume was measured in 22 full-term lambs using the double label, radioiodinated human serum albumin-125 (RIHSA-125) plasma tag and radiochromium-51 (Cr51) red cell tag dilution technique. Nine lambs (Group I) were born naturally and unassisted. Thirteen lambs were delivered by cesarean section, of which eight (Group II) had early clamping and five (Group III) had late clamping of their umbilical cords. The size of placental transfussion, as reflected in mean red cell volume (RCV) was 36.7 ± 2.1 ml/kg in Group I, which was significantly greater than that of Group II, 29.8 ± 2.0 ml/kg; but smaller than that of Group III, 50.4 ± 2.3 ml/kg. The findings indicate that a partial, rather than a complete, placental transfusion occured in the naturally born lambs. It is suggested that this may reflect Nature's way of regulating the volemic state in the newborn lamb.     

The physiological roles of placental corticotropin releasing hormone in pregnancy and childbirth

In response to stress, the hypothalamus releases cortiticotropin releasing hormone (CRH) that travels to the anterior pituitary, where it stimulates the release of adrenocorticotropic hormone (ACTH). ACTH travels to the adrenal cortex, where it stimulates the release of cortisol and other steroids that liberate energy stores to cope with the stress. During pregnancy, the placenta synthesises CRH and releases it into the bloodstream at increasing levels to reach concentrations 1,000 to 10, 000 times of that found in the non-pregnant individual. Urocortins, which are CRH analogues are also secreted by the placenta. Desensitisation of the maternal pituitary to CRH and resetting after birth may be a factor in post-partum depression. Recently, CRH has been found to modulate glucose transporter (GLUT) proteins in placental tissue, and therefore there may be a link between CRH levels and foetal growth. Evidence suggests CRH is involved in the timing of birth by modulating signalling systems that control the contractile properties of the myometrium. In the placenta, cortisol stimulates CRH synthesis via activation of nuclear factor kappa B (NF-κB), a component in a cellular messenger system that may also be triggered by stressors such as hypoxia and infection, indicating that intrauterine stress could bring forward childbirth and cause low birth weight infants. Such infants could suffer health issues into their adult life as a result of foetal programming. Future treatment of these problems with CRH antagonists is an exciting possibility.