Biomedical subjects

S A Pangas

Publications and source records attributed to S A Pangas.

4 recordsLinked to original sources

PubMed2004

Human cumulus granulosa cell gene expression: a predictor of fertilization and embryo selection in women undergoing IVF.

BACKGROUND: A biochemical marker for embryo development would increase the chance of a successful pregnancy with IVF by optimizing oocyte and embryo selection, and allow fewer embryos to be transferred. In this study, we correlated cumulus granulosa cell gene expression of hyaluronic acid synthase 2 (HAS2), cyclooxygenase 2 (COX2; PTGS2) and gremlin (GREM1) with subsequent embryo development in search of a parameter for embryo selection. METHODS: Cumulus cell gene expression was determined prospectively on eight consecutive patients undergoing IVF with ICSI. Immediately following oocyte retrieval, the cumulus was stripped from the oocyte, and cumulus gene expression for PTGS2, HAS2 and GREM1 was assessed using a one-step real-time quantitative RT-PCR assay. Oocyte quality, fertilization and embryo morphology were correlated to relative gene expression. RESULTS: Gene expression data were available on cumulus cells from 108 oocytes that developed into 70 embryos (64.8% fertilization rate). Cumulus PTGS2, HAS2 and GREM1 expression was higher from oocytes that developed into higher quality embryos (grades 3, 4 and 5) compared with lower quality embryos (grades 1 and 2) (P<0.05, P<0.001 and P<0.001, respectively). HAS2 and GREM1 expression was also higher from the cumulus surrounding oocytes that gave rise to higher grade embryos (P<0.001). The expression of PTGS2 and HAS2 was 6-fold higher, and that of GREM1 was 15-fold higher in cumulus yielding higher grade embryos versus lower grade embryos. CONCLUSION: PTGS2, HAS2 and GREM1 gene expression correlates to morphological and physiological characteristics and provides a novel approach to predict human embryo development. Ultimately, with better predictors of follicular and embryonic health, higher quality embryos can be selected and transferred, reducing higher order pregnancy rates.

Adult↗

PubMed2002

Production and purification of recombinant human inhibin and activin.

Inhibin and activin are protein hormones with diverse physiological roles including the regulation of pituitary FSH secretion. Like other members of the transforming growth factor-beta gene family, they undergo processing from larger precursor molecules as well as assembly into functional dimers. Isolation of inhibin and activin from natural sources can only produce limited quantities of bioactive protein. To purify large-scale quantities of recombinant human inhibin and activin, we have utilized stably transfected cell lines in self-contained bioreactors to produce protein. These cells produce approximately 200 microg/ml per day total recombinant human inhibin. Conditioned cell media can be purified through column chromatography resulting in dimeric mature 32-34 kDa inhibin A and 28 kDa activin A. The purified recombinant proteins maintain their biological activity as measured by traditional in vitro assays including the regulation of FSH in rat anterior pituitary cultures and the regulation of promoter activity of the activin-responsive promoter p3TP-luc in tissue culture cells. These proteins will be valuable for future analysis of inhibin and activin function and have been distributed to the US National Hormone and Peptide Program.

Activins↗

PubMed2000

Activin signal transduction pathways.

Many of the signal transduction pathways required for mammalian endocrine cell function are conserved from flies and worms. These model organisms permitted the illumination of the biological properties of ligands and provided systems in which cellular coactivating molecules could be identified rapidly. Our knowledge about the activin signaling components has been advanced tremendously by the work carried out in these systems. Subsequent research is beginning to reveal the complex interactions that serve to regulate this signaling pathway.

Activins↗

PubMed2000

Structure and expression of a membrane component of the inhibin receptor system.

The purification and cloning of a membrane-anchored proteoglycan with affinity for inhibin A are described. Bovine pituitary membranes were isolated, and membrane-anchored proteins were solubilized and used as an enriched source of inhibin binding protein. The extract was passed over an inhibin A affinity column, and a protein, designated p120, was identified as an inhibin-binding moiety. A partial amino acid sequence was determined for the protein, which matched two human complementary DNAs (cDNAs) in the database. The full-length cDNA predicts a 1336-amino acid glycoprotein. Full-length p120-encoding cDNAs were isolated from human testis RNA and cloned into expression vectors. Two p120 messenger RNA transcripts of 4.6 kb and 2 kb are detected in rat pituitary by RNA blot analysis. Similar analysis of rat testis RNA revealed transcripts of identical molecular mass, albeit at lower abundance. To determine the cellular localization of p120 in pituitary and testis, an antibody directed against the predicted extracellular domain of the protein was generated and used in an immunohistochemical analysis of thin tissue sections. p120 immunostaining is coincident with FSHbeta immunopositive gonadotrope cells in rat pituitary. p120 staining is intense in the testicular Leydig cells, which bind iodinated inhibin but not iodinated activin. In summary, an inhibin-binding protein has been isolated that is produced in tissues that are targets of inhibin action.

Activin Receptors↗