Biomedical subjects

D J Ruiter

Publications and source records attributed to D J Ruiter.

257 records · Page 15Linked to original sources

PubMedDate not supplied

Antigen expression of metastasizing and non-metastasizing human melanoma cells xenografted into nude mice.

In order to study differences in antigen expression related to the different stages of the process of metastasis of human melanoma cell lines, we determined the expression pattern of a series of well-characterized genes in a set of human melanoma cell lines with different metastatic behavior in nude mice. This set included non-metastatic (IF6, 530), sporadically metastatic (M14, Mel 57), and frequently metastatic (BLM, MV3) cell lines after subcutaneous inoculation. To study the phenotype of these cell lines both the cultured cells and representative samples of local tumors at the inoculation site and their metastases in the lungs were immunostained with a panel of monoclonal antibodies directed against melanocytic differentiation or progression antigens. Although most cell lines (IF6, 530, M14 and Mel 57) showed HLA-DR expression in vitro, these antigens were lacking in all xenografted lesions studied with exception of the 530 cell line. 530 Xenografts, however, showed a dramatic down-regulation of HLA-DR compared with the cell line in vitro. The same phenomenon was seen with respect to ICAM-1 expression. The expression of all other antigens studied in xenografts, both in subcutaneous tumors and in lung lesions, was in general comparable to that in the melanoma cell lines in vitro, with exception of the 530 cell line. In all melanoma cell lines except 530 the degree of intra- and interlesional heterogeneity regarding the expression of all antigens studied was limited. Remarkably, comparison of the immunophenotype of the frequently metastasizing (BLM, MV3) and the sporadically (M14, Mel 57) or non-metastasizing (IF6, 530) cell lines showed that the two frequently metastasizing cell lines had marked expression of the progression antigens VLA-2 and epidermal growth factor receptor, and lack of expression of the differentiation antigen NKI-beteb. These findings warrant further studies on the role of these antigens in the process of metastasis of human melanoma cells in nude mice.

Adult↗

PubMedDate not supplied

Expression and susceptibility to modulation by interferons of HLA class I and II antigens on melanoma cells. Immunohistochemical analysis and clinical relevance.

Immunohistochemical analysis for non-polymorphic determinants of HLA class I or class II antigens has been greatly facilitated by the use of monoclonal antibodies. Studies on the distribution of these antigens in tumour lesions emphasize their role in the tumour-host interaction and in tumour histopathology, especially as additional markers in the assessment of prognosis of melanoma patients. Changes in the expression of HLA antigens on tumour cells in vitro as induced by gamma-interferon may also occur in vivo as a result of local production by the T lymphocytic infiltrate in tumours.

Cells, Cultured↗

PubMedDate not supplied

Progression markers in metastasizing human melanoma cells xenografted to nude mice (review).

The past decade transplants of human tumors in nude mice have been increasingly used as an experimental model for local tumor growth and dissemination. A few human melanoma cell lines have been described that give rise to metastases in nude mice after subcutaneous inoculation. First we give an overview of some relevant literature with respect to the pathogenesis of tumor metastasis, models to study human cancer metastasis, neoplastic progression and the detection of antigens involved in metastasis. Finally we describe our results concerning the morphological and immunohistochemical profile of six different human melanoma cell lines and their xenograft lesions in nude mice using a set of monoclonal antibodies recognizing different categories of human melanoma-associated antigens. From the data we conclude that the nude mouse mouse model appears suitable to study the role of melanoma-associated progression markers in the pathogenesis of metastasis.

Animals↗

PubMedDate not supplied

Ultrastructure of normal epithelial cells in Papanicolaou-stained cervical smears. An application of a modified open-face embedding technique for transmission electron microscopy.

The results of an open-face embedding technique applied to Papanicolaou-stained uterine cervical smears are presented. By this technique, cells are smeared on a plastic sheet, fixed in 1.5% buffered glutaraldehyde and stained by the Papanicolaou method; areas of special interest are then selected by light microscopy for electron microscopic observations. Thus, a comparison is possible between the light microscopic characteristics of cells in smear preparations and their ultrastructural counterparts. The good ultrastructural preservation allowed detailed study of nuclei and cytoplasm. The endocervical cells had intact nuclei with nuclear envelope, Golgi apparatus, well-preserved mitochondria and two types of secretory material. The superficial and intermediate squamous cells showed loss of desmosomes; dense, fine cytoplasmic fibrils; small, fatty droplets; and degenerated nuclei with loss of the nuclear envelope. Compared with ultrastructural studies on cervical tissues, the intermediate cells in cervical smears were more degenerated, presumably because predominantly degenerated intermediate cells exfoliate. This study indicates that the light microscopic impression of the nuclear appearance is misleading: in the routine smear the nuclei of superficial and intermediate cells may look "intact" and "well preserved" whereas ultrastructurally the nuclei are degenerated.

Cytological Techniques↗

PubMedDate not supplied

Atypical indifferent (reserve) cells in the cervical epithelium and their exfoliative pattern.

The ultrastructure of light microscopically selected atypical indifferent (reserve) cells in cervical smear preparations is described and compared with their ultrastructure in histologic sections. These atypical indifferent cells have a blastlike chromatin pattern and an intact nuclear membrane. The cytoplasm, however, was often damaged or absent; if present, it showed no sign of differentiation. In the histologic sections, these atypical indifferent cells were found in reserve-cell hyperplasia, in small numbers in squamoid dysplasia and as basally located cells in atypical endocervical epithelium. In contrast to the indifferent cells, the squamoid dysplastic cells and atypical endocervical cells in smear preparations had intact cytoplasm; however, the nuclear membrane of the squamoid dysplastic cells was often interrupted. This study indicates that atypical indifferent (reserve) cells can be recognized by light microscopy in smear preparations and that the fact that the cytoplasm is often damaged or absent is probably due to its undifferentiated nature. These cells can originate in pure atypical reserve-cell hyperplasia, dysplasia or atypical endocervical epithelium. In view of the great importance of these cells in the morphogenesis of squamoid and adenomatous carcinoma of the cervix, it seems of paramount importance that they be identified in cervical smears.

Cell Nucleus↗