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Biomedical subjects

H Lobeck

Publications and source records attributed to H Lobeck.

130 records · Page 8Linked to original sources
PubMedDate not supplied

Epstein-Barr virus DNA, intermediate filaments and epithelial membrane antigen in nasopharyngeal carcinoma.

The aim of this study was to investigate the expression of intermediate filaments (cytokeratin, vimentin), epithelial membrane antigen (EMA) and the presence of Epstein-Barr virus (EBV) DNA in undifferentiated nasopharyngeal carcinoma (NPC). A high incidence of nuclear signals in NPC was found in primaries and regional lymph node metastases (70%), using 35S-labelled probes of EBV plasmids for in-situ hybridization. Keratinizing squamous cell carcinomas were EBV-negative. All carcinomas were immuno-reactive for cytokeratin (KL-1). 45% of the carcinomas were positive for vimentin. The expression of epithelial membrane antigen was restricted to epithelial cells and reduced in NPC as compared to the distribution pattern of cytokeratin. Both EBV DNA and vimentin in NPC were present in 9 cases. However, in 5 cases NPC were harboring EBV but were not immunoreactive for anti-vimentin antibodies. In no case was a vimentin-positive NPC also EBV-negative. The identification of cytokeratin subtypes revealed no specific cytokeratin pattern in NPC. The expression of vimentin in NPC is not specific for EBV, but seems to reflect the loss of inter-epithelial contact in anaplastic carcinomas.

Adult↗
PubMedDate not supplied

Cytologic and immunocytologic studies of peripheral T-cell lymphomas.

Lymph node aspirates from 18 peripheral T-cell lymphomas (PTLs) were analyzed. Cytologic and immunocytologic studies were performed on Cytospin preparations using the alkaline phosphatase-antialkaline phosphatase method with a panel of monoclonal antibodies (CD3, CD4, CD8, CD19 and CD30). The cytologic diagnosis was confirmed by histologic investigation. Nine lymph node aspirates from patients with Lennert's lymphoma, angioimmunoblastic (AILD)-type PTL and pleomorphic small-cell-type PTL were composed predominantly of small-to-intermediate-sized lymphocytes. An admixture of plasma cells, eosinophils, neutrophils, lymphocytes with an irregular nucleus, granula in the cytoplasm or abundant cytoplasm was also seen. Nine lymph node aspirates from patients with T-immunoblastic lymphoma, pleomorphic large-cell-type PTL and large-cell anaplastic (Ki-1+) lymphoma showed marked cytologic heterogeneity. Immunocytologic investigation of the aspirates using the antibodies CD3, CD4, CD8, CD19 and CD30 was helpful for the differentiation of PTLs from reactive lymphadenopathy and other malignant lymphomas. A strong predominance of CD3+ cells was found in only seven cases. The aspirates expressed a helper/inducer phenotype in 11 cases and a suppressor/cytotoxic phenotype in 4 cases. A T-cell phenotype not corresponding to the normal T-cell phenotype was found in nine cases. In 15 of the 18 cases, the number of CD19+ cells was found to be less than 15%. The large cells of the large-cell anaplastic (Ki-1+) lymphoma expressed the antigens CD30 and CD45 and were negative for CD15. These findings indicate that immunocytologic studies can be used in improving the cytologic diagnosis of PTLs.

Antibodies, Monoclonal↗
PubMedDate not supplied

The lateral cyst of the neck: congenital or acquired?

An outer rim of lymphoid tissue and an inner epithelial lining of squamous composition form the lateral (branchial) cyst of the neck. According to the particular pattern of keratin polypeptides, branchial mass inner lining is shown to be homologous to upper digestive tract (UDT) squamous epithelia. Furthermore, immunostaining of tissue sections with a polyclonal antibody highly specific for the major acidic UDT keratin 13 demonstrates that the epithelium in question is composed of both basal and normally differentiated, i.e. non-keratinizing suprabasal (spinous) cells. 'Import' into a neck lymph node, and rapid growth of oropharyngeal crypt epithelial cells is suggested to initiate a sequence of events leading to an acquired lymphoepithelial mass that may actually present as a 'branchial cyst'.

Branchioma↗