Blood flow in the umbilical artery in physiological pregnancy

Fetal umbilical artery flow was measured with Doppler ultrasound technique in 206 cases of the uncomplicated pregnancy. Indices A/B and R.I. were calculated. It was shown that vascular resistance in the umbilical artery is decreasing in the normal pregnancy parallel to its development and is manifested by the changes in A/B and R.I. values.     

Host physiological status determines phage-like particle distribution in the lysate

Bacteriophage morphotype diversity and latent period duration upon induction were correlated with the host population growth. The prophages of the lysogenic Vibrio sp. (DSM14379) were induced with mitomycin C in a batch culture with different salinity, substrate concentration or composition, and at different temperatures. Under all experimental conditions, phages were induced and a population of different complete and incomplete phage-like particles was observed in the lysate. Under favorable growth conditions, the phage-like particle community in the lysate was overpopulated with phage tail-like rigid rods. The number of rods was reduced in samples with low organic carbon concentration, samples with 8% and 10% NaCl, and samples induced at 40 and 43 degrees C. Although all lysates contained all phage-like particle-size fractions, their relative abundances varied. Up to a fivefold difference in phage-like particle size was observed in lysates. Size distribution of phage-like particles changed along temperature, salinity and organic carbon gradients. Results also indicated that the latent period of the induced phage-like particle population converged to approximately 90 min above a growth rate of 1.0 h(-1). At lower host growth rates, the latent period generally increased. However, at 40 and 43 degrees C and at low peptone-yeast extract concentration in the growth medium, the latent period remained short. We propose that different host physiological conditions influence organic matter composition upon prophage induction and may thus affect virus-controlled flow of the energy and carbon in the ecosystem.     

The physiological role of estradiol 17-sulfate during pregnancy

To clarify the physiological role of estradiol 17-sulfate (ES) during pregnancy, experiments were conducted and the following results were obtained: (1) serum or urinary ES levels rose as a function of gestational age; (2) placental microsomes showed fairly high 2- and 4-hydroxylase activity for ES; and (3) the catechol products, 2- and 4-hydroxy-ES, had a strong inhibitory effect upon the in vitro production of lipid peroxides. These results suggest that ES actsas a precursor to the catechol metabolites which maintain normal gestation. This is coincident with the negative correlation of serum levels in ES and lipid peroxides observed in late pregnancy.     

Rapid assessment of physiological status in Escherichia coli using fluorescent probes

Rapid and direct viability assessment of Escherichia coli in filtered, sterile lake water was possible using multiparameter flow cytometry. Fluorescent dyes were used as probes for different cellular functions (membrane potential, membrane integrity and intracellular enzyme activity), which were correlated with the ability of the cells to respond to nutrient addition while in a stressed state. Measurement of several criteria circumvented limitations imposed by other methods, and provided extensive evidence for the validity of the methods for monitoring cell viability during adoption of a viable-but-non-culturable state in starved E, coli. Macromolecular staining was concomitantly used to monitor changes in cellular protein, RNA and DNA as additional indicators of physiological status during starvation/stress.     

The physiological versus the spectrophotometric status of phytochrome in corn coleoptiles

The influence of red light in altering the phototropic sensitivity of corn coleoptiles (Zea mays L., cultivar Burpee Barbecue Hybrid) is compared with the spectrophotometric status of the phytochrome they contain. The distribution of measurable phytochrome corresponds roughly with the distribution of sensitivity to red light for physiological change. Both phytochrome concentration and red light sensitivity are maximal in the coleoptile tips. Red light pretreatments which reduce total phytochrome by about 50%, however, do not alter subsequent red light sensitivity of the phototropic system. Dosages of red light sufficient to saturate the physiological system are two orders of magnitude too small to induce measurable phytochrome transformation. The log-dosage-response curves for physiological change and for phytochrome transformation do not have the same slopes. The time course for appearance, mainconcentration of the far-red-absorbing form of phytochrome over a broad range of tenance, and decay of the physiological response is independent of the measurable concentrations. The following hypothesis is proposed: the phytochrome mediating the alteration in phototropic sensitivity is only a small proportion of the total present. This small active fraction is physically and kinetically independent of the bulk measurable, and is packaged in some manner which facilitates its transformation in both directions.     

Fecal near infrared spectroscopy to discriminate physiological status in giant pandas

Giant panda (Ailuropoda melanoleuca) monitoring and research often require accurate estimates of population size and density. However, obtaining these estimates has been challenging. Innovative technologies, such as fecal near infrared reflectance spectroscopy (FNIRS), may be used to differentiate between sex, age class, and reproductive status as has been shown for several other species. The objective of this study was to determine if FNIRS could be similarly used for giant panda physiological discriminations. Based on samples from captive animals in four U.S. zoos, FNIRS calibrations correctly identified 78% of samples from adult males, 81% from adult females, 85% from adults, 89% from juveniles, 75% from pregnant and 70% from non-pregnant females. However, diet had an impact on the success of the calibrations. When diet was controlled for plant part such that "leaf only" feces were evaluated, FNIRS calibrations correctly identified 93% of samples from adult males and 95% from adult females. These data show that FNIRS has the potential to differentiate between the sex, age class, and reproductive status in the giant panda and may be applicable for surveying wild populations.     

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.     

Production and reception of growth factors in placenta during physiological pregnancy and the pregnancy, complicated with gestosis

30 women with physiological pregnancy and 28 women with gestosis were examined. The content of epidermal growth factor (EGF), vascular-endothelial growth factor (VEGF) and their receptors were studied in the early chorion obtained after abortion and in the full-term placenta using the ELISA method. The process of normal gestation was characterized by the increase of the placental production both of the EGF and VEGF. During the pregnancy complicated with gestosis and miscarriage in the first trimester the content of EGF and its receptor was lower compared to the physiological values. For VEGF and its receptor opposite changes were found: the increase of quantity of the growth factor and the decrease of its receptor. In the case of gestosis and term of pregnancy the content of the both growth factors and their receptors was lower than in corresponding controls. The changes in production of the angiogenic growth factors and their receptors in the placenta may have the pathogenic importance in the development of gestosis.     

Activation of the neuregulin/ErbB system during physiological ventricular remodeling in pregnancy

The neuregulin-1 (NRG1)/ErbB system has emerged as a paracrine endothelium-controlled system in the heart, which preserves left ventricular (LV) performance in pathophysiological conditions. Here, we analyze the activity and function of this system in pregnancy, which imparts a physiological condition of LV hemodynamic overload. NRG1 expression and ErbB receptor activation were studied by Western blot analyses in rats and mice at different stages of pregnancy. LV performance was evaluated by transthoracic echocardiography, and myocardial performance was assessed from twitches of isolated papillary muscles. NRG1/ErbB signaling was inhibited by oral treatment of animals with the dual ErbB1/ErbB2 tyrosine kinase inhibitor lapatinib. Analyses of LV tissue revealed that protein expression of different NRG1 isoforms and levels of phosphorylated ErbB2 and ErbB4 significantly increased after 1-2 wk of pregnancy. Lapatinib prevented phosphorylation of ErbB2 and ERK1/2, but not of ErbB4 and protein kinase B (Akt), revealing that lapatinib only partially inhibited NRG1/ErbB signaling in the LV. Lapatinib did not prevent pregnancy-induced changes in LV mass and did not cause apoptotic cell death or fibrosis in the LV. Nevertheless, lapatinib led to premature maternal death of ～25% during pregnancy and it accentuated pregnancy-induced LV dilatation, significantly reduced LV fractional shortening, and induced abnormalities of twitch relaxation (but not twitch amplitude) of isolated papillary muscles. This is the first study showing that the NRG1/ErbB system is activated, and plays a modulatory role, during physiological hemodynamic overload associated with pregnancy. Inhibiting this system during physiological overload may cause LV dysfunction in the absence of myocardial cell death.     

Alterations in lipid peroxidation and antioxidant status in pregnancy with preeclampsia

Soy consumption is associated with a lower risk of atherosclerotic disease in the oriental population. Genistein is a soy isoflavone bearing estrogenic properties. Previous experiments in our laboratory demonstrated the potentiation of endothelium-independent relaxation of coronary artery by both estrogen and genistein. The potentiating effects of both estrogen and genistein were mediated through the cAMP-signaling pathway. We hypothesize that genistein could enhance protein kinase A (PKA) activity in porcine coronary artery smooth muscle, thereby offering a mechanism for the potentiation of vascular relaxation by genistein. In our study, a high concentration of genistein (10^−4.5 M) significantly increased PKA activity in porcine coronary artery rings. While genistein at 10^−5.5 M and forskolin at 10⁻⁷ M had no effect on PKA activity, the combination of the two compounds at the prescribed concentrations caused a significant increase in PKA activity. The increase in PKA activity by genistein was abolished by SQ 22536 (adenylate cyclase blocker), but not by NF 449 (Gs protein blocker) or ICI 182780 (estrogen receptor antagonist). Our results suggest that the action of genistein is mediated via adenylate cyclase, but does not appear to involve Gs protein or ICI 182780-sensitive estrogen receptor.     

Steroid hormones: their physiological role and diagnostic value during pregnancy

Steroid hormones play a key role in the beginning, development and termination of gestation. This reveiw is devoted for physiological effects of estrogens, progesterone, cortisole, ACTH, CRH in various pregnancy events: implantation, fetus development, maternal adaptation and birth initiation. Priority is fixed for estrogens--steroids that vastly increase maternal circulating blood value, induce progesterone action on uterus, regulate fetal "hypothalamic-pituitary-adrenocortical" axis, control free cortisole level in feminine blood. Diagnostic criterions of steroid hormone determination durijng pregnancy are presented. To day unconjugated estriol is the only steroid hormone that implicated in total pregnancy screening programs. Its concentration reduction has been noted in pregnancies with Dawn syndrome, some child enzyme defetcs, intrauterine growth retardation and fetal death incidents.