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Biomedical subjects

J Bartek

Publications and source records attributed to J Bartek.

171 records · Page 10Linked to original sources
PubMed1987

Human breast epithelial xenografts: an immunocytochemical and ultrastructural study of differentiation and lactogenic response.

Fragments of ductal and lobular epithelium ('organoids') produced by collagenase digestion of reduction-mammoplasty specimens were injected into athymic 'nude' mice. These heterospecific tissues were accepted without rejection, and the presence of xenografts was confirmed by cytology, immunocytochemistry and chromatin staining. Lactation, as confirmed by immunocytochemical and ultrastructural criteria, was observed in the grafted human epithelium during murine pregnancy at both intra- and extra-mammary sites.

Actins↗
PubMed1985

Patterns of expression of keratin 19 as detected with monoclonal antibodies in human breast tissues and tumours.

The monoclonal antibodies BA16 and BA17 directed to different epitopes on human keratin 19 have been tested for their reaction with normal breast and with benign and malignant breast lesions and associated tissue. In Western blots of gel-separated extracts of fibroadenomas, malignant tumours or normal mammary epithelial cells, the antibodies reacted with only one component of 40 kd molecular weight. Immunoperoxidase staining of sections of normal breast tissues showed all basal cells and a few luminal cells to be unstained by the antibodies. The distribution of the unstained (keratin 19-) luminal cells in the mammary tree is consistent with that of cells with the proliferative potential to give rise to the growth of terminal ductal lobular units (TDLU) seen at pregnancy. A total of 42 benign and 141 malignant lesions were stained with the antibodies, and a clear difference in staining pattern was seen between the benign and malignant tumours. All but 3 of the benign lesions showed a heterogeneous staining pattern with 5-50% unstained cells. In contrast, the cancer cells in 106/116 invasive primary tumours and in all 21 metastatic lesions examined showed a homogeneously positive reaction with antibodies BA16 and BA17: the malignant cells in 4 cases of Paget's disease also showed homogeneously positive staining with the antibody. In the malignant tumours, the observed homogeneity in expression of keratin 19 was confined to the malignant cells; tumour-associated normal tissue and benign proliferative lesions contained keratin 19-cells. Seven pure in situ tumours were examined and 5 showed the homogeneous pattern of staining characteristic of invasive tumours while 2 contained a high number of keratin 19-cells. A general model is presented to explain the presence of keratin 19-cells in benign proliferation and the dominance of keratin 19-cells in invasive carcinoma.

Animals↗
PubMed1985

Production and characterization of monoclonal antibodies to human casein. A monoclonal antibody that cross-reacts with casein and alpha-lactalbumin.

Four hybridomas have been produced that secrete monoclonal antibodies to human beta-casein, a protein synthesized by fully differentiated breast epithelial cells. The antibodies have been characterized on immunoblots and have been shown to react with methanol: acetone-fixed sections of human lactating mammary gland. Immunoblots show that three of these antibodies react with casein whereas one, F20.10, also recognizes an epitope present on human alpha-lactalbumin. Computer analysis of the amino acid sequences of these two milk proteins reveals very little sequence homology, leading to the conclusion that the three-dimensional shape, rather than the primary sequence, is important in this cross-reactivity.

Amino Acid Sequence↗
PubMed1985

A subclass of luminal epithelial cells in the human mammary gland, defined by antibodies to cytokeratins.

Two monoclonal antibodies, BA16 and BA17, have been developed using a detergent-insoluble extract of human mammary epithelial organoids as immunogen. Indirect immunofluorescent staining of cultured cells showed that the component reacting with the antibodies was filamentous and the intensity of staining was stronger in mitotic cells. Immunoblotting of cell extracts showed that both antibodies react with only one band of 40 X 10(3) molecular weight, which was present in keratin-enriched extracts of cells or organoids. Furthermore, the tissue distribution of the component reacting with the antibodies was that predicted for human keratin 19. The antibodies showed differences in the intensity of staining of cells or tissue sections fixed and prepared in different ways indicating that they reacted with different epitopes. The pattern of expression of the 40 X 10(3) Mr keratin by normal mammary epithelial cells was investigated by immunoperoxidase staining of tissue sections, cultured milk cells, and organoids of different sizes cultured in collagen gels. It was found that basal or myoepithelial cells did not express this keratin. Some heterogeneity of expression of this component was seen in luminal epithelial cells, found almost exclusively in the smaller structures. These cells did, however, express other keratins characteristic of luminal cells. The distribution in the mammary tree of the luminal cells that did not express the 40 X 10(3) Mr keratin appears to be similar to that expected for cells with the proliferative potential to produce new terminal ductal lobular units or an increase in branching of existing terminal ductal lobular units. It is shown that these cells have considerable proliferative potential by the fact that they form large colonies in milk cell cultures.

Animals↗