Elevated plasma beta-endorphin levels in pregnant women and their neonates.

Using radioimmunoassay technique β-endorphin levels were measured in the plasma of women undergoing labour and partirition and in the plasma of their neonates. The level of immunoreactive β-endorphin in the plasma of women undergoing labour was found to be significantly elevated (mean values: 38–135 fmoles/ml) above the levels found in non-pregnant women (mean values: 5–10 fmoles/ml). After birth, the level of β-endorphin-like immunoreactivity in maternal venous plasma was significantly higher than that in the umbilical vein and artery plasma of the new-borns, but there was no arterio-venous difference in the neonatal plasma. Since the antiserum used displayed the same avidity for human β-endorphin and β-lipotropin chromatographic separation of the immunoreactive components was performed by gelfiltration. Both peptides were found in the plasma of non-pregnant women, in maternal plasma and in the plasma of the neonates. In addition, high amounts of both peptides were found in the fetal pituitary gland showing that the fetus can probably produce its own peptides.     

Variations in plasma zinc in older men and women

The study evaluated the biological and analytical variance in plasma zinc from 36 adults 60–88 yr of age. Blood samples were taken by finger-prick from each subject on d 1, 2, 3, 8, and 15. Days 1, 2, and 3 were selected to describe daily variation; 1, 8, and 15 were selected to describe weekly variation. Plasma Zn was analyzed by flame atomic absorption using a microinjection technique. Variation was partitioned into analytical, intraindividual, and interindividual components using analysis of variance. The interindividual variability was generally greater than the intraindividual variability. The variability for plasma zinc was about 30% and was substantially greater than reported for younger populations. This variability could not be attributed to the covariates examined, including zinc intake from food and supplements, serum albumin, and C-reactive protein. The variability would affect the accuracy of plasma zinc status based on a blood sample collected on a single day. With the microtechnique used in this study, 8 sample days would be needed to estimate plasma Zn with 95% confidence level and 20% level of accuracy.     

Measurement of plasma and tissue relaxin concentrations in the pregnant hamster and fetus using a homologous radioimmunoassay

A homologous hamster relaxin RIA was developed to evaluate plasma and tissue concentrations of relaxin in the latter half of pregnancy in this species. Relaxin protein and mRNA were localized using antibodies developed to synthetic hamster relaxin and gene-specific molecular probes, respectively. Molecular weight and isoelectric point of the synthetic and native hormones were identical by electrophoretic methods, and synthetic hamster relaxin was active in the mouse interpubic ligament bioassay. Synthetic hormone was used as tracer and standard with rabbit antiserum to the synthetic hormone in the RIA. Relaxin was assayed in blood samples recovered from the retro-orbital plexus on Days 6, 8, 10, 12, 14, 15, and 16 of gestation and on Days 1 and 5 postpartum. Relaxin was first detected on Day 8 of gestation (3.7 +/- 0.6 ng/ml), increased to reach a maximum in the evening of Day 15 (826.0 +/- 124.0 ng/ml), and decreased by Day 16 (day of parturition). Relaxin concentrations were assayed in aqueous extracts of implantation sites (Days 6, 8, and 10) and chorioallantoic placentae (Days 12, 14, and 15). Concentrations were low on Day 6 (0.02 +/- 0.001 microg/g tissue), increased to Day 15 (6.96 +/- 0.86 microg/g tissue), and subsequently declined by the evening of Day 15. Relaxin protein and mRNA were localized to primary and secondary giant trophoblast cells in the chorioallantoic placental trophospongium. However, relaxin protein was not localized in ovaries of pregnant animals or oviductal tissues of cycling animals. Significant quantities of relaxin were detected in the serum of fetal hamsters recovered on Day 15.     

Estrone concentration in the peripheral plasma of pregnant and non-pregnant gilts

A rapid radioimmunoassay for estrone (total unconjugated and sulfated) was developed to determine plasma estrone (E1) concentrations in inseminated gilts that conceived and those that had not. Thirty-one 160 day-old prepuberal gilts were induced to ovulate with gonadotropins and were artificially inseminated 10 hr before the expected time of ovulation (Day 1 - day of insemination). Unconjugated E1 and E1SO4 were extracted from 20 to 500 microl of plasma twice with 5 ml of tetrahydrafuran:ethyl acetate (1:1). Aliquots of a standard E1SO4 preparation were dissolved in 500 microl of distilled water and extracted at the same time as the plasma samples. The dried extracts were solvolyzed for 1 hr at 50 degrees C in 0.6 ml of glacial acetic acid:ethyl acetate (1:1), and the dried residue was redissolved in 0.2 ml of distilled water and extracted once with 2 ml of diethyl ether. Twenty of 31 gilts were pregnant at Days 29 to 31 of the induced cycle. Plasma E1 in pregnant gilts increased from 85 pg/ml on Day 18 to 702, 1879 and 2793 pg/ml, respectively, on Days 22, 25 and 29 to 31. Three of the non-pregnant gilts had plasma progesterone secretion maintained until Day 22; they also had a transitory increase in plasma E1 on Day 22 (215 pg/ml). Some blastocysts may have been present to exert a temporary luteotropic effect, but not enough blastocysts to completely overcome the luteolytic effect of the uterus. Quantification of plasma E1SO4 could be used as a pregnancy test in the pig.     

Selenium detoxification of heavy metals: a possible mechanism for the blood plasma

Among the activities of the essential trace element selenium is the ability to reduce the toxicity of heavy metal ions like cadmium(II) and mercury(II). Detoxification often depends on the metabolic reduction of selenium to hydrogen selenide; the mechanism generally advanced to explain such selenium/metal interactions is that selenide combines with heavy metal ions to give a metal selenide which is metabolically inert. However, this hypothesis does not consider circumstances where selenide is quickly removed by other reactions. Given the ease with which selenide is oxidized, such conditions are likely to occur in the blood plasma, an environmental rich in oxidizing agents and a site for many selenium/metal interactions. Using polarography to monitor both selenide and cadmium, we have found that selenide reacts rapidly in vitro with the disulfide bonds present in bovine serum albumin in preference to forming cadmium selenide. We hypothesize that a similar reaction occurs in the blood plasma with the disulfide bonds of plasma proteins to generate thiol groups on the protein involved, and that these newly formed thiols are responsible for the observed reduction of metal toxicity through the ability to chelate heavy metal ions.     

Intrathalline and size-dependent patterns of activity in Lasallia pustulata and their possible consequences for competitive interactions

1. In dense populations of the saxicolous lichen Lasallia pustulata the margins of adjacent thalli overlap each other in intraspecific competition for space and light.
2. In situ non-destructive monitoring of hydration-dependent potential photosynthetic activity by modulated fluorescence systems in different parts of the thallus shows that the activity is structured by a centre-to-margin gradient, with the centre of the thallus remaining active for substantially longer periods than the margins when the thalli dry up after being activated by wetting. The pattern reflects the water status of different parts of the thallus; the margins which are thin and exposed dry up first.
3. The activity pattern within individual lichen thalli suggests that marginal overlapping between neighbours may have a less detrimental effect on the shadowed individuals than expected from a pure consideration of the amount of area shadowed. Because the centre of the lichen thallus is active for longer periods, shadowing of this region may possibly be more harmful per area unit than an overlap at the less active margins.
4. Larger thalli are active for substantially longer periods than small ones. Even the margins of larger thalli tend to be active for a longer period than the centre of small thalli.     

Monitoring blood plasma leptin and lactogenic hormones in pregnant sows

The mechanism of action of leptin in pregnant breeding sows, in which hyperphagia is managed through dietary strategies, is yet to be clarified. The aim of this study was to monitor leptin concentrations and their interactions with lactogenic hormones in Large White×Landrace breeding multiparous sows (n=15). All sows showed a normal body condition (mean body condition score: 2.96). Blood samples were collected the day after weaning the litters, at insemination, every 15 days up to day 45 of pregnancy and every 7 days from day 46 to farrowing. At delivery, the placenta was collected for the analysis of leptin and leptin receptor expressions. Plasma leptin levels increased from the end of mid gestation (day 72) and remained high until farrowing (P<0.05). As expected, plasma prolactin (PRL), low during most of pregnancy, increased during the 2 weeks before farrowing (P<0.05), whereas progesterone levels reached plateau at 30 days of gestation and decreased at farrowing (P<0.05). Cortisol levels peaked close to farrowing (P<0.05). Leptin was expressed in the placenta, where the receptor expression analysis showed the presence of the short form but not of the long form. A positive correlation was found between leptin and PRL concentrations during mid (r=0.430; P<0.001) and late (r=0.687; P<0.001) pregnancy, and with progesterone in early pregnancy (r=0.462; P<0.05). During late gestation, a positive correlation was observed between leptin and cortisol (r=0.585; P<0.001). Our results suggested that, in restrictively fed pregnant sows, the leptin levels increased from the end of mid pregnancy to delivery, confirming the presence of leptin resistance. We showed a correlation between leptin and lactogenic hormones during different stages of pregnancy in sows. Lactogenic hormones show pregnancy-specific changes in their secretion and all may become involved in modulating leptin signal.     

Functional consequences of SARS-CoV-2 infection in pregnant women,fetoplacental unit,and neonate

The SARS-CoV-2 infection causes COVID-19 disease, characterized by acute respiratory distress syndrome, bilateral pneumonia, and organ failure. The consequences of maternal SARS-CoV-2 infection for the pregnant woman, fetus, and neonate are controversial. Thus, it is required to determine whether there is viral and non-viral vertical transmission in COVID-19. The disease caused by SARS-CoV-2 leads to functional alterations in asymptomatic and symptomatic pregnant women, the fetoplacental unit and the neonate. Several diseases of pregnancy, including COVID-19, affect the fetoplacental function, which causes in utero programming for young and adult diseases. A generalized inflammatory state and a higher risk of infection are seen in pregnant women with COVID-19. Obesity, diabetes mellitus, and hypertension may increase the vulnerability of pregnant women to infection by SARS-CoV-2. Alpha, Delta, and Omicron variants of SARS-CoV-2 show specific mutations that seem to increase the capacity of the virus to infect the pregnant woman, likely due to increasing its interaction via the virus S protein and angiotensin-converting enzyme 2 receptors. This review shows the literature addressing to what extent COVID-19 in pregnancy affects the pregnant woman, fetoplacental unit, and neonate. Prospective studies that are key in managing SARS-CoV-2 infection in pregnancy are discussed.     

The association of plasma peroxiredoxin 3 with insulin in pregnant women

Peroxiredoxin 3 (PRX3) is predominantly located in mitochondria and plays a major role in scavenging hydrogen peroxide of mitochondria. In the present study, we detected plasma PRX3 in pregnant women receiving oral glucose tolerance test at 24–28 gestational weeks. Plasma PRX3 was significantly increased about 1?h later than insulin secretion. In vitro detection of PRX3 in mouse islet cells showed up-regulation by more than 2-fold at 1?h and reached its top at 2?h of glucose stimulation, and the PRX3 level in cultured mediums was concomitantly elevated in a glucose concentration-dependent manner. In addition, both fasting plasma insulin and PRX3 were significantly higher in the subjects of term pregnancy as compared to that at 24–28 gestational weeks, and there was a positive correlation between plasma PRX3 and insulin. Our results indicate that PRX3 plays an active role in the response to insulin release. The positive association of plasma PRX3 and insulin suggest PRX3 to be a potential indicator of high insulin resistance.