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933 results on '"Burghardt, Robert"'

7. The history of interferon-stimulated genes in pregnant cattle, sheep, and pigs.

Author

Johnson, Gregory A., Bazer, Fuller W., Burghardt, Robert C., Heewon Seo, Guoyao Wu, Cain, Joe W., and Pohler, Ky G.

Subjects
MONONUCLEAR leukocytes, INTERFERON regulatory factors, HEALTH of cattle, EMBRYO implantation, GENETIC transcription
Abstract

Expression of the classical interferon (IFN) stimulated genes (ISGs) increases in the endometrial stroma and glandular epithelium (GE) through activation of signal transducer and activator of transcription (STAT) signaling in response to the secretion of IFN tau (IFNT) and IFN gamma (IFNG) by the conceptuses of ruminants, including cattle and sheep, and pigs, respectively. The first of the classical ISGs to be characterized was ISG15 in cattle. Classical ISGs are not expressed by the endometrial luminal epithelium (LE) due to the expression of interferon regulatory factor 2 (IRF2) in the LE that prevents the expression of ISGs in the LE. Classical ISG expression in the endometrium serves as a reliable indicator of conceptus health and elongation in cattle. There are also nonclassical ISGs that are upregulated in endometrial LE in response to progesterone (P4) that are further stimulated by IFNT in sheep, the intracellular signaling pathway responsible for IFN effects on expression is unknown. ISGs are also upregulated in extrauterine tissues including CL and peripheral blood mononuclear cells (PBMCs). The expression of ISGs by the PBMCs of cattle serves as an early prognosticator of pregnancy. The physiological roles of ISGs remain obscure, but evidence suggests that they are at least in part involved in modifying the immune system to support endometrial remodeling necessary for the successful implantation of the conceptus. Our understanding of these ISGs is primarily the result of work from the laboratories of Drs Fuller Bazer, Thomas (Tod) Hansen, Gregory Johnson, Hakhyun Ka, Patrick Lonergan, Troy Ott, and Thomas Spencer. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Use of multiple singular value decompositions to analyze complex intracellular calcium ion signals

Author

Martinez, Josue G., Huang, Jianhua Z., Burghardt, Robert C., Barhoumi, Rola, and Carroll, Raymond J.

Subjects
Statistics - Applications, Computer Science - Computer Vision and Pattern Recognition, Physics - Biological Physics, Quantitative Biology - Quantitative Methods
Abstract

We compare calcium ion signaling ($\mathrm {Ca}^{2+}$) between two exposures; the data are present as movies, or, more prosaically, time series of images. This paper describes novel uses of singular value decompositions (SVD) and weighted versions of them (WSVD) to extract the signals from such movies, in a way that is semi-automatic and tuned closely to the actual data and their many complexities. These complexities include the following. First, the images themselves are of no interest: all interest focuses on the behavior of individual cells across time, and thus, the cells need to be segmented in an automated manner. Second, the cells themselves have 100$+$ pixels, so that they form 100$+$ curves measured over time, so that data compression is required to extract the features of these curves. Third, some of the pixels in some of the cells are subject to image saturation due to bit depth limits, and this saturation needs to be accounted for if one is to normalize the images in a reasonably unbiased manner. Finally, the $\mathrm {Ca}^{2+}$ signals have oscillations or waves that vary with time and these signals need to be extracted. Thus, our aim is to show how to use multiple weighted and standard singular value decompositions to detect, extract and clarify the $\mathrm {Ca}^{2+}$ signals. Our signal extraction methods then lead to simple although finely focused statistical methods to compare $\mathrm {Ca}^{2+}$ signals across experimental conditions., Comment: Published in at http://dx.doi.org/10.1214/09-AOAS253 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org)

Published
2010
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16. Pig conceptuses utilize extracellular vesicles for interferon-gamma-mediated paracrine communication with the endometrium†

Author

Cain, Joe W, Seo, Heewon, Bumgardner, Katie, Lefevre, Carli, Burghardt, Robert C, Bazer, Fuller W, and Johnson, Gregory A

Abstract

Interferon-gamma (IFNG) is a pro-inflammatory cytokine secreted by the porcine conceptus (embryo and extra-embryonic membranes) during the peri-implantation period of pregnancy. IFNG modifies the endometrial inflammatory immune response and is required for the implantation and survival of the conceptus. It is not known how IFNG from the conceptus trophectoderm is transported across the endometrial luminal epithelium (LE). In the present study, immunofluorescence analyses detected immunoreactive IFNG protein in both the trophectoderm and endometrial LE on Day 15 of pregnancy, while our previous research localized IFNG mRNA only to conceptus trophectoderm. Using minced endometrial explants to disrupt the barrier posed by the intact endometrial LE, treatment with recombinant IFNG induced the expression of genes that were not induced when IFNG was infused into the uterine lumen in vivo by McLendon et al. (Biology of Reproduction.2020;103(5):1018–1029). We hypothesized that during pregnancy extracellular vesicles (EVs) serve as intercellular signaling vehicles to transport conceptus-derived IFNG across the intact endometrial LE and into the stromal compartment of the uterus. Western blotting detected the presence of IFNG in EVs isolated from the uterine fluid of pregnant gilts, but not nonpregnant gilts. Real-time PCR demonstrated increased expression of IFNG-stimulated genes in EV-treated endometrial explants and EV-mediated IFNG transport was confirmed in whole uterine sections cultured with EVs from Day 15 of pregnancy. These results suggest that EVs are involved in IFNG transport across the endometrial LE to enable paracrine communication between the conceptus and cells within the endometrial stroma.Summary SentenceDuring the peri-implantation period, conceptus-derived IFNG may be transported across the uterine luminal epithelium by extracellular vesicles for communication with cells in the stroma.Graphical Abstract

Published
2024
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20. Implantation and Establishment of Pregnancy in the Pig

Author

Geisert, Rodney D., Johnson, Gregory A., Burghardt, Robert C., Korf, Horst-Werner, Series editor, Clascá, Francisco, Series editor, Kmiec, Zbigniew, Series editor, Timmermans, Jean-Pierre, Series editor, Sutovsky, Peter, Series editor, Singh, Baljit, Series editor, Geisert, Rodney D., editor, and Bazer, Fuller W., editor

Published
2015
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22. Understanding placentation in ruminants: a review focusing on cows and sheep.

Author

Johnson, Gregory A., Bazer, Fuller W., Seo, Heewon, Burghardt, Robert C., Wu, Guoyao, Pohler, Ky G., and Cain, Joe W.

Subjects
TROPHOBLAST, RUMINANTS, EMBRYO implantation, SHEEP, COWS, BIOLOGICAL extinction, MISCARRIAGE
Abstract

Mammals differ regarding their placentae, but in all species placental trophoblasts interact intimately with the uterine endometrium to mediate the transfer of nutrients from the mother to the embryo/fetus through the closely juxtaposed microcirculatory systems of the uterus and placenta. Placentation in ruminants is intermediate between the non-invasive type, as observed in the epitheliochorial placenta of pigs, and the invasive type, as observed in the haemochorial placentae of mice and humans. In ruminants, placental trophoblast cells invade uterine endometrial tissue, but invasion is believed to be limited to the endometrial luminal epithelium (LE). In the LE there are varying degrees of syncytialisation among species, with syncytialisation being more extensive in sheep than cows. The hallmarks of placentation in ruminants include: (1) an extended period in which conceptuses (embryos and associated placental membranes) elongate and must be supported by secretions (histotroph) from the uterus; (2) a cascade involving an array of adhesion molecules that includes integrin-mediated attachment of the conceptus trophoblast to the endometrial LE for implantation; (3) syncytialisation of the developing early placenta, a process for which there is currently limited understanding; and (4) development of placentomes that define the cotyledonary placentae of cows and sheep, and provide haemotrophic support of fetal development. The United States cattle industry is burdened by losses of pregnancies of up to 45% of cows bred. Many of these losses in ruminant species are the result of errors in the development of the placenta. This review describes and discusses what is currently known about some of the complex molecular and physiological events that underlie successful placentation in cows and sheep. Increased understanding of placentation is critical for developing advances to improve reproductive efficiency in animal agriculture enterprises that provide high-quality animal protein for human consumption. Photograph by Dr Robert C. Burghardt. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Infection of equine bronchial epithelial cells with a SARS-CoV-2 pseudovirus

Author

Legere, Rebecca M., primary, Allegro, Angelica R., additional, Affram, Yvonne, additional, da Silveira, Bibiana Petri, additional, Fridley, Jennifer L., additional, Wells, Kelsey M., additional, Oezguen, Numan, additional, Burghardt, Robert C., additional, Wright, Gus A., additional, Pollet, Jeroen, additional, Bordin, Angela I., additional, de Figueiredo, Paul, additional, Leibowitz, Julian L., additional, and Cohen, Noah D., additional

Published
2023
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