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- Brabant, G, et al.
(författare)
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E-cadherin: a differentiation marker in thyroid malignancies.
- 1993
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Ingår i: Cancer research. - 0008-5472. ; 53:20, s. 4987-93
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Tidskriftsartikel (refereegranskat)abstract
- Loss of E-cadherin (uvomorulin), a Ca(2+)-dependent cell adhesion molecule required for normal epithelial function, has been attributed a pathogenetic role in tumor invasion. The expression of E-cadherin was studied in normal and neoplastic follicular epithelium of the human thyroid by Northern blot analysis and immunofluorescence on frozen tissue sections. In the normal thyroid (n = 10) and in benign thyroid disorders (n = 21; toxic diffuse goitre; multinodular goitre; follicular adenomas), E-cadherin mRNA levels were equally high and the follicles were generally stained, mainly along the lateral surface of the epithelial cells, by the anti-E-cadherin monoclonal antibody. In anaplastic thyroid carcinomas (n = 6) E-cadherin expression was very low or lacking. In papillary carcinomas (n = 23), E-cadherin mRNA levels varied from nearly normal to highly reduced, which roughly correlated with the overall immunofluorescence intensity. However, the immunostaining also revealed a heterogeneous "all-or-nothing" expression of E-cadherin among adjacent cells in the same tumor. In the follicular carcinomas (n = 9), E-cadherin mRNA levels were in general rather high but the immunostaining varied considerably. A few papillary and follicular tumors lacked immunoreactive E-cadherin in spite of high mRNA levels. In oxyphilic (Hürthle) cell tumors, comprising both adenomas (n = 4) and carcinomas (n = 2), E-cadherin immunoreactivity was reduced and distributed intracellularly rather than at the cell surface. The expression of E-cadherin in relapsing thyroid carcinomas and in tumors with metastatic spreading was, irrespective of the histiotype, low or lacking. Sequential Northern analysis revealed a close correlation between the expression levels of E-cadherin and the thyrotropin receptor. Together, the data suggest that in human thyroid malignancies both gene expression and posttranscriptional control of E-cadherin may be impaired.
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| 4. |
- Mölne, Johan, 1958, et al.
(författare)
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Non-polarized cell surface expression of HLA-A,B,C and HLA-DR antigens in Graves' thyroid follicle cells.
- 1991
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Ingår i: Autoimmunity. - 0891-6934. ; 10:3, s. 189-99
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Tidskriftsartikel (refereegranskat)abstract
- The intrathyroidal distribution and cell surface location of HLA-A,B,C and HLA-DR antigens was studied in polarized thyroid follicle cells from Graves' (n = 11) and normal (n = 3) thyroid tissue, using light and electron microscopy. Cryosections and isolated, open follicle segments were incubated with monoclonal antibodies against HLA-A,B,C and HLA-DR antigens and with patient sera containing autoantibodies against the microsomal antigen/thyroperoxidase. Immunoreactivity for HLA-A,B,C and HLA-DR on isolated thyroid follicle cells was frequently detected in Graves' disease, but absent in normal glands. There was a large variation in the immunolabelling between follicles as well as between different glands. Both HLA-A,B,C and HLA-DR immunoreactivity were detected on the apical and the basal surface of the follicle cells. Microsomal antigen/thyroperoxidase immunoreactivity was restricted to the apical cell surface. In contrast to normal tissue, HLA-DR positive cells with a dendritic or macrophage-like morphology were frequent in Graves' tissue. These cells adhered directly to the basal surface of isolated follicle segments. We conclude that HLA antigens are, unlike thyroid-specific plasma membrane constituents, expressed in a non-polarized manner at the surface of the follicular epithelium. These observations might have implications on the immune recognition of thyroidal autoantigens in Graves' disease.
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| 5. |
- Olevik, David, et al.
(författare)
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Critique of an experiment regarding quantum states in a gravitational field and possible geometrical explanations
- 1992
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We discuss an experiment conducted by Nesvizhevsky et al. As it is the first experiment claimed to have observed gravitational quantum states, it is imperative to investigate all alternative explanations of the result. In a student project course in applied quantum mechanics, we consider the possibility of quantummechanical effects arising from the geometry of the experimental setup, due to the "cavity" formed. We try to reproduce the experimental result using geometrical arguments only. Due to the influence of several unknown parameters our result is still inconclusive.
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