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Fluorescent ligands, used in histocytochemistry, do not discriminate between estrogen receptor-positive and receptor-negative human tumor cell lines (1984)

Berns, Els M. J. J. ; Mulder, Eppo ; Rommerts, Focko F. G. ; [et al.]

Springer

Breast cancer research and treatment 4 (1984), S. 195-204

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ISSN: 1573-7217

Keywords: estrogen receptor ; fluorescence histochemistry ; steroid conjugates ; tumor cell lines

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Summary A cell line containing estrogen receptors (MCF-7) and a cell line lacking estrogen receptors (PC-93) were used for a comparison of biochemical and histochemical procedures to detect estrogen receptors. We evaluated three different fluorescent estrogen derivatives: 17β-estradiol-6-carboxymethyloxime-bovine serum albumin-fluorescein isothiocyanate, 17β-estradiol-17-hemisuccinate-fluoresceinamine, and coumestrol. The main results were: 1. The relative binding affinities of these ligands for the estrogen receptor were between 0.1 and 2% of the affinity of estradiol. 2. Fluorescent staining of the cells showed no relation to the presence of estrogen receptors. 3. Staining was not suppressed with excess estradiol- 17β, which is known to prevent binding of low affinity ligands to estrogen receptors. 4. Cells with intact membranes were not stained after treatment with the albumin-linked estrogen derivative; only cells with damaged cell membranes were stained. 5. Treatment of cells with 17β-estradiol-17-hemisuccinate-fluoresceinamine resulted in a fluorescent labeling of the cytoplasm in intact and artificially damaged cells. 6. Coumestrol caused only fluorescence of the cytoplasm in intact cells. It is concluded that estrogen receptors cannot be detected with these low affinity ligands. Fluorescence of these cells is probably due to binding of the ligands to low affinity binding sites. The presence of these low affinity binding sites appears not to be related to the presence or absence of estrogen receptors and can therefore not be used to discriminate between estrogen receptor-positive and receptor-negative tumor cells.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01806485

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Fucosylation of glycoproteins in rat spermatocytes and spermatids (1982)

Grootegoed, J. Anton ; Krüger-Sewnarain, Bea C. ; Jutte, Nicolet H. P. M. ; [et al.]

New York, NY : Wiley-Blackwell

Gamete Research 5 (1982), S. 303-315

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ISSN: 0148-7280

Keywords: spermatocytes ; spermatids ; glycoproteins ; fucose ; acrosome ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: Glycoprotein synthesis in pachytene spermatocytes and round spermatids, isolated from rat testes, was studied by analysis of the incorporation of (3H)-fucose. The isolated germ cells were capable of incorporating (3H)-fucose into cell-bound, acid-precipitable components for an incubation period of at least 23 hours (at 32°C). In young spermatids, engaged in the formation of the acrosome, (3H)-fucose was incorporated into more than 16 different glycoproteins within the molecular weight range of 20.000-100,000. A qualitatively similar set of glycoproteins was found to be labeled in spermatocytes. Radioautography showed that after 4 hr most of the incorporated radioactivity was present at one pole in the perinuclear zone of spermatocytes and spermatids, which could reflect incorporation of fucose in the Golgi apparatus. The newly fucosylated glycoproteins were associated with a particulate subcellular fraction (membrane fraction). Trypsin treatment of whole cells after 25 hours of incubation with (3H)-fucose, however, did not cause significant lysis of tritiated glycoproteins.From the results it was concluded that the majority of the newly fucosylated glycoproteins in spermatocytes and spermatids remained associated with an intracellular membrane system, presumably the Golgi apparatus and the vesicles that arise from this structure, to be deposited subsequently in proacrosomic granules and the acrosome. The results also suggest that initiation of the synthesis of spermatidal glycoproteins occurs during the prophase of meiosis in spermatocytes.

Additional Material: 6 Ill.