scholarly journals The role of albumin in the release of platelet-activating factor by mouse preimplantation embryos in vitro

Reproduction ◽  
1997 ◽  
Vol 109 (2) ◽  
pp. 309-318 ◽  
Author(s):  
A. J. Ammit ◽  
C. O'Neill
Keyword(s):  
Platelet Activating Factor ◽  
Preimplantation Embryos

Intracellular localisation of platelet-activating factor during mammalian embryo development in vitro: a comparison of cattle, mouse and human

2019 ◽  
Vol 31 (4) ◽  
pp. 658
Author(s):  
L. T. M. Vandenberghe ◽  
B. Heindryckx ◽  
K. Smits ◽  
M. Popovic ◽  
K. Szymanska ◽  
...  
Keyword(s):  
Platelet Activating Factor ◽  
Preimplantation Embryos ◽  
Mammalian Embryo ◽  
Developmental Potential ◽  
Nuclear Envelope Breakdown ◽  
Cytosolic Phospholipase ◽  
Carrier Molecule ◽  
Development In Vitro ◽  
Intracellular Localisation

Platelet-activating factor (PAF) is a well-known marker for embryo quality and viability. For the first time, we describe an intracellular localisation of PAF in oocytes and embryos of cattle, mice and humans. We showed that PAF is represented in the nucleus, a signal that was lost upon nuclear envelope breakdown. This process was confirmed by treating the embryos with nocodazole, a spindle-disrupting agent that, as such, arrests the embryo in mitosis, and by microinjecting a PAF-specific antibody in bovine MII oocytes. The latter resulted in the absence of nuclear PAF in the pronuclei of the zygote and reduced further developmental potential. Previous research indicates that PAF is released and taken up from the culture medium by preimplantation embryos invitro, in which bovine serum albumin (BSA) serves as a crucial carrier molecule. In the present study we demonstrated that nuclear PAF does not originate from an extracellular source because embryos cultured in polyvinylpyrrolidone or BSA showed similar levels of PAF in their nuclei. Instead, our experiments indicate that cytosolic phospholipase A2 (cPLA2) is likely to be involved in the intracellular production of PAF, because treatment with arachidonyl trifluoromethyl ketone (AACOCF3), a specific cPLA2 inhibitor, clearly lowered PAF levels in the nuclei of bovine embryos.

Acute lung injury in endotoxemic pigs: role of leukotriene B4

1995 ◽  
Vol 78 (3) ◽  
pp. 1121-1131 ◽  
Author(s):  
T. J. VanderMeer ◽  
M. J. Menconi ◽  
B. P. O'Sullivan ◽  
V. A. Larkin ◽  
H. Wang ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Platelet Activating Factor ◽  
Leukotriene B4 ◽  
Important Mediator ◽  
Preliminary Study ◽  
Receptor Upregulation ◽  
To Receive

The role of leukotriene B4 (LTB4) in the pathogenesis of acute lung injury was examined in endotoxemic pigs. In a preliminary study, the activity and specificity of an LTB4-receptor antagonist, LY-306669, were evaluated. In vitro, LY-306669 completely blocked the functional upregulation of phagocyte opsonin receptors induced by LTB4 but had a much smaller effect on opsonin receptor upregulation induced by platelet-activating factor. In pigs treatment with LY-306669 prevented leukopenia induced by injection of authentic LTB4 but had no effect on the hematologic or hemodynamic effects of PAF or U-48816, a thromboxane-A2 mimetic. In a second study, pigs received an intravenous priming dose of lipopolysaccharide (LPS) at time (t) = -18 h and were randomized to receive 1) no further treatment (n = 5), 2) LPS (250 micrograms/kg over 1 h beginning at t = 0 h) and LY-306669 (10 mg/kg bolus and 3 mg.kg-1.h-1 infusion beginning at t = -15 min) (n = 7), or 3) LPS and vehicle (n = 6). Treatment with LY-306669 significantly ameliorated LPS-induced hypoxemia, pulmonary edema, and alveolitis. These data suggest that LTB4 is an important mediator of pulmonary dysfunction and transendothelial migration of neutrophils in LPS-induced acute lung injury.

scholarly journals Transcription of paternal Y-linked genes in the human zygote as early as the pronucleate stage

Zygote ◽  
1994 ◽  
Vol 2 (4) ◽  
pp. 281-287 ◽  
Author(s):  
Asangla Ao ◽  
Robert P. Erickson ◽  
Robert M.L. Winston ◽  
Alan H Handysude
Keyword(s):  
Mammalian Species ◽  
Blastocyst Stage ◽  
Preimplantation Embryos ◽  
Human Embryos ◽  
Cell Stage ◽  
Gonad Differentiation ◽  
Embryonic Genome ◽  
Human Preimplantation Embryos

SummaryGlobal activation of the embryonic genome occurs at the 4– to 8–cell stage in human embryos and is marked by continuation of early cleavage divisions in the presence of transcriptional inhibitors. Here we demonstrate, using recerse transcripase–polymerase chin reaction (Rt–PCR), the presence of transcripts for wo paternal Y chromosomal genes, ZFY and SRY in human preimplantation embryos. ZFY transcripts were detected as early as the pronucleate stage, 20–24 h post-insemination In vitro and at intermediate stages up to the blastocyst stage. SRY Transcripts were also detected at 2–cell to blastocyos observed in many mammalian species focuses attention on the role of events in six determination prior to gonad differentiation.

Role of platelets in contraction of canine tracheal muscle elicited by PAF in vitro

1988 ◽  
Vol 65 (2) ◽  
pp. 914-920 ◽  
Author(s):  
K. J. Popovich ◽  
G. Sheldon ◽  
M. Mack ◽  
N. M. Munoz ◽  
P. Denberg ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Airway Smooth Muscle ◽  
Airway Epithelium ◽  
Platelet Activating Factor ◽  
Smooth Muscle Contraction ◽  
Tracheal Smooth Muscle ◽  
Serotonin Antagonist

To elucidate mechanisms of platelet-activating factor (PAF)-induced contraction, we studied the effect of PAF on 203 canine tracheal smooth muscle (TSM) strips from 45 dogs in vitro in the presence and absence of platelets. PAF (10(-11) to 10(-7) M) alone caused no contraction of TSM even in the presence of airway epithelium. In the presence of 2 x 10(5) platelets/microliter, PAF was an extremely potent contractile agonist (threshold 10(-11) M). This response was inhibited by the PAF antagonist, CV-3988 (10(-6) M), and reversed by the serotonin antagonist, methysergide (EC50 = 3.7 +/- 0.79 x 10(-9) M). Neither atropine nor chlorpheniramine (10(-9) to 10(-6) M) attenuated the response to PAF + platelets. In the presence of platelets, 10(-7) M PAF caused an increase in perfusate concentration of serotonin from 0.93 +/- 0.037 x 10(-8) to 1.7 +/- 0.046 x 10(-8) M (P less than 0.001). Tachyphylaxis, previously demonstrated to be irreversible, was shown to be a platelet-dependent phenomenon; contraction could be repeated in the same TSM after addition of fresh platelets. We demonstrate that PAF-induced contraction of canine TSM is caused by the release of cellular intermediates such as serotonin from platelets. We also demonstrate the site of PAF-induced tachyphylaxis in airway smooth muscle contraction.

scholarly journals The Functional Paradox of CD43 in Leukocyte Recruitment: A Study Using CD43-deficient Mice

1998 ◽  
Vol 188 (11) ◽  
pp. 2181-2186 ◽  
Author(s):  
Richard C. Woodman ◽  
Brent Johnston ◽  
Michael J. Hickey ◽  
Diane Teoh ◽  
Paul Reinhardt ◽  
...  
Keyword(s):  
Platelet Activating Factor ◽  
Flow Chamber ◽  
Cell Interactions ◽  
Dual Function ◽  
Wild Type ◽  
Flow Conditions ◽  
Deficient Mice

Although there is considerable evidence implicating a role for CD43 (leukosialin) in leukocyte cell–cell interactions, its precise function remains uncertain. Using CD43-deficient mice (CD43−/−) and intravital microscopy to directly visualize leukocyte interactions in vivo, we investigated the role of CD43 in leukocyte–endothelial cell interactions within the cremasteric microcirculation under flow conditions. Our studies demonstrated significantly enhanced leukocyte rolling and adhesion after chemotactic stimuli in CD43−/− mice compared with wild type mice. Using an in vitro flow chamber, we established that the enhanced rolling interactions of CD43−/− leukocytes, primarily neutrophils, were also observed using immobilized E-selectin as a substrate, suggesting that passive processes related to steric hindrance or charge repulsion were likely mechanisms. Despite increased adhesion and rolling interactions by CD43−/− leukocytes, we uncovered a previously unrecognized impairment of CD43−/− leukocytes to infiltrate tissues. Oyster glycogen–induced neutrophil and monocyte infiltration into the peritoneum was significantly reduced in CD43−/− mice. In response to platelet activating factor, CD43−/− leukocytes were impaired in their ability to emigrate out of the vasculature. These results suggest that leukocyte CD43 has a dual function in leukocyte–endothelial interactions. In addition to its role as a passive nonspecific functional barrier, CD43 also facilitates emigration of leukocytes into tissues.

scholarly journals Immune factors in human embryo culture and their significance

Medicina ◽  
2010 ◽  
Vol 46 (4) ◽  
pp. 233 ◽  
Author(s):  
Živilė Čerkienė ◽  
Audronė Eidukaitė ◽  
Audronė Usonienė
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Platelet Activating Factor ◽  
Human Leukocyte ◽  
Preimplantation Embryos ◽  
Embryonic Cells ◽  
Embryo Viability ◽  
Transforming Growth Factor Α

There is increasing evidence that human development before implantation is regulated by embryonically and maternally derived growth factors. The “regulators” of embryonic origin such as soluble human leukocyte antigen G, platelet-activating factor, Th1/Th2 cytokines, insulinlike growth factor, epidermal growth factor, transforming growth factor α, colony-stimulating factor, platelet-derived growth factor may be used as indicators of embryo viability and implantation potential. The data prove the infl uence of growth factors on the development and growth of preimplantation embryos. Though there is a lot of research in the field of biomarkers during folliculogenesis and maternal-fetal interface, only few of them deal with regulators derived from embryonic cells to the cultivation medium. The aim of our study was to summarize the research dealing with immune markers produced by embryos in vitro and to estimate their impact on the cell growth, viability and implantation potential.

Actions of platelet activating factor (PAF) on gametes and embryos: clinical aspects

1992 ◽  
Vol 4 (4) ◽  
pp. 399 ◽  
Author(s):  
IL Pike ◽  
AJ Ammit ◽  
C O'Neill
Keyword(s):  
Platelet Activating Factor ◽  
Preimplantation Embryos ◽  
Human Embryos ◽  
Clinical Aspects ◽  
Embryo Viability ◽  
Human Follicular Fluid ◽  
Body Tissues ◽  
Paf Antagonists ◽  
Human Ivf

Platelet activating factor (PAF) is a phospholipid widespread in body tissues. Previous reviews have discussed its production by preimplantation embryos and the evidence implicating it as an autocrine mediator in aspects of gamete and embryo physiology. Human spermatozoa contain variable amounts of PAF, the amount contained depending on the source and method of preparation of the sperm. Incubation of human sperm with PAF tends to increase their forward velocity, especially in samples with slow motility. PAF treatment causes an increase in the proportion of acrosome-reacted sperm and in their ability to penetrate both zona-free hamster ova and cervical mucus. PAF has been found in human follicular fluid at ovulation. A role for PAF in ovulation has been suggested, because PAF antagonists reduce the rate of ovulation in rats. In some studies, modest improvements to mouse in vitro fertilization (IVF) rates have been achieved with PAF supplementation of media under specific conditions. Furthermore, in the rabbit and mouse, PAF antagonists have been reported to inhibit fertilization in vivo and in vitro respectively. However, addition of PAF to human IVF medium, but only at the time of insemination and fertilization, had no effect on either fertilization or pregnancy rates. Sensitive bio- and immuno-assays have shown that PAF is secreted by human embryos into their fluid milieu. PAF secretion by these zygotes during culture, although markedly variable, has been correlated with the achievement of pregnancy and pregnancy outcome. Although the secretion of PAF by the mouse embryo decreases during culture in vitro, exogenous PAF enhances embryo viability during culture. Similarly, culture of human zygotes in PAF-supplemented medium prior to embryo transfer significantly increases the chance of achieving pregnancy. Both the implantation and live-birth rates are increased in human IVF by addition of PAF to the medium.

Impact of the periconceptional environment on the programming of adult disease

2009 ◽  
Vol 1 (2) ◽  
pp. 87-95 ◽  
Author(s):  
A. J. Watkins ◽  
E. S. Lucas ◽  
T. P. Fleming
Keyword(s):  
Expression Patterns ◽  
Preimplantation Embryos ◽  
Phenotypic Change ◽  
Mammalian Development ◽  
Adult Disease ◽  
Environmental Perturbations ◽  
Periconceptional Period

The periconceptional period of mammalian development has been identified as an early ‘developmental window’ during which environmental conditions may influence the pattern of future growth and physiology. Studies in humans and animal models have revealed that factors such as maternal nutritional status or in vitro culture and manipulation of developing gametes and preimplantation embryos can impact upon the long-term health and physiology of the offspring. However, the mechanisms involved in the programming of adult disease in response to altered periconceptional development require increased investigation. The role of epigenetic modifications to DNA and chromatin organisation has been identified as a likely mechanism through which environmental perturbations can affect gene expression patterns resulting in phenotypic change. This study will highlight the sensitivity of two critical stages in early mammalian development, gametogenesis and preimplantation development. We will detail how changes to the immediate environment can not only impact upon developmental processes taking place at that time, but can also affect long-term aspects of offspring health and physiology. We will also discuss the emerging role of epigenetics as a mechanistic link between the environment and the later phenotype of the developing organism.

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