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Biomedical subjects

T Löning

Publications and source records attributed to T Löning.

At least 163 records · Page 9Linked to original sources
PubMed1982

Comparative investigation of keratin-filaments in normal tissues and tumours of skin, oral mucosa, salivary glands and thymus.

Antibodies against different fractions of keratins can be helpful in various fields of special pathology. Antibodies against "small" and "large" keratins permit to evaluate epithelial maturation in skin and oral mucosa. In addition, disturbances of keratinization during inflammatory processes and malignant transformation can be analyzed. The main application of antibodies against the entire fractions of keratins is the detection of the epithelial nature of a neoplasm. By this tool, particular problems in surgical pathology concerning differential diagnosis can be handled in an easier way. Among the different tissues and their neoplasms, examples of the analysis of thymus tumours and salivary gland tumours are presented. Immunoreactivity with keratin antibodies depends crucially on tissue processing. In the normal diagnostic procedure, good results are regularly obtained if cryostat or Bouin-fixed paraffin-embedded sections are used.

Adenoma↗
PubMed1981

Immunocytochemical demonstration of filamentous structures in the parotid gland. Occurrence of keratin and actin in normal and tumoral parotid gland with special respect to the myoepithelial cells.

The aim of this study was to analyze the filament distribution in the parotid gland and their tumors. A correlation to the histogenetic implications and histological properties was attempted. Normal rat and human parotid glands as well as pleomorphic adenomas and squamous cell carcinomas of this gland were examined by the indirect immunoperoxidase technique using antibodies to the keratin polypeptide of 67,000 dalton, and 55,000 dalton and anti-actin auto-antibodies. Both keratin and actin antigens were demonstrated in the duct system and in the myoepithelial cells of the normal salivary glands. The acinar cells remained negative. In pleomorphic adenomas, there were numerous keratin-positive spindle-shaped cells which represented the so-called myoepithelial cells. These cells were demonstrated to contain actin, too. The tubular duct-like structures were labeled by keratin antiserum and by anti-actin auto-antibodies. In squamous cell carcinomas, the majority of the tumor cells were strongly labeled by keratin antibodies. Actin was detected in these malignant cells, too. Our results show important differences in the cellular elements of the normal salivary glands with regard to their filament distribution. In normal and tumoral conditions, our findings support the hypothesis of the epithelial nature of the myoepithelial cells. Our preliminary results encourage the research of filamentous structures for scientific and diagnostic purposes.

Actins↗
PubMed1981

The epithelial framework of the thymus in normal and pathological conditions. Immunohistochemical demonstration of keratin in an autopsy series.

Autopsy specimens of normal human thymus, from cases of accidental involution, follicular hyperplasia, thymomas and a teratoma were investigated by immunocytochemistry using specific immune sera to small and large keratins. Keratin antisera represent a "marker" of both Hassall's corpuscles (HC) and so-called epithelial reticular cells. There were no apparent differences in keratin polypeptides distribution between cortical and medullary thymic epithelial cells. In accidental involution, the epithelial framework became prominent: epithelial cortical borders and epithelial perivascular sheaths appeared often to be discontinuous structure. The central and occasionally cystic spaces of HC did not react with keratin antisera. In follicular hyperplasia, almost solid epithelial aggregates were seen which were located around germinal centers. In thymic tumours, neoplastic epithelial cells displayed a marked immunoreactivity with keratin antisera. Immune sera against keratin filaments represent an interesting tool in thymus research and in the diagnostic pathology of thymic tumours.

Aged↗
PubMed1980

[The effect of ethylene oxide and chemical disinfectant residues upon the larynx- and tracheal mucosa of rabbits (author's transl)].

Residues of ethylene oxide and chemical disinfectants in anesthesia supplies can cause side effects in patients. For this reason we intubated 37 New Zealand rabbits with PVC endotracheal tubes of 3.0-3.5 mm inner diameter. The tubes were sterilized with ethylene oxide and aerated for 24 or 48 h in room air. At this time they still held 600 resp. 80 ppm ethylene oxide as we had determined by gaschromatography. For comparison tubes were soaked in 2% activated Cidex or 10% Gigasept and watered for 1 h in sterile water. 5 not intubated animals served as controls. All rabbits were sacrificed after 48 h and larynx and trachea examined microscopically for histological changes. In all intubated animals we found hyperemia, edema formation and cellular infiltration. In addition there were epithelial erosions in about 60% and 4 uclers. The findings were considerably more pronounced in animals which had been intubated with tubes containing 600 ppm ethylene oxide. Almost all tubes cause mechanical irritation of the respiratory tract. Additional chemical trauma is not to be expected, however, if they are watered adequately after treatment with disinfecting solutions resp. aerated sufficiently after ethylene oxide sterilization.

Animals↗
PubMed1979

Plasma cells and immunoglobulin-synthesis in oral precancer and cancer. Correlation with dysplasia, cancer differentiation, radio- and chemotherapy.

The subepithelial and peritumoral inflammatory infiltrates of 202 oral premalignant and malignant lesions -- 108 leukoplakias and 94 squamous cell carcinomata with different grades of dysplasia were examined using an immunoenzymatic method. In addition, the influence of radiation and bleomycin-therapy on the stromal reaction of 24 carcinomata was studied. The incidence of immunoglobulin labelled plasma cells (IgA and IgG) was twice as high in those cases of leukoplakia where dysplasia was present. The number of plasma cells, especially IgA- and IgG-containing plasma cells, decreased significantly with progressive tumor dedifferentiation. The plasma cell response differed before and after radiation with a decrease in IgA- and IgG-containing plasma cells after therapy. In contrast, bleomycin-therapy did not produce distinct changes in the humoral and cellular stromal reaction. In the epithelium, IgA and IgG were localized throughout all epithelial layers in leukoplakias with dysplasia. This finding indicates a leakage of locally synthesized immunoglobulins through an altered oral mucosa. This investigation reveals alterations in the local immune homoeostasis of the oral mucosa in premalignant and malignant lesions which varies with the grade of dysplasia, tumor differentiation and therapy.

Bleomycin↗
PubMed1979

[Biochemical and morphologic studies on prostaglandins E and F in the normal and inflamed gingiva].

With the help of a radioimmunoassay for prostaglandins E and F, an attempt was made to determine the actual concentration of these substances in normal and inflammatorily altered gingival tissue. The content of PGE and PGF was significantly higher in the inflammatorily altered gingiva than in normal tissue. Morphologic examination using immunologic methods showed prostaglandin E particularly in the monocytes.

Gingiva↗
PubMedDate not supplied

Expression patterns of the cell-cycle inhibitor p27 and the cell-cycle promoter cyclin E in the human placenta throughout gestation: implications for the control of proliferation.

The rapid development of the placenta necessitates a high proliferative potential and cell-division rate. This, coupled with a high capacity for invasion, could confer on the placental tissue a tumour-like character. To exclude this, tight mechanisms of control are necessary for both proliferation and invasiveness. Despite their importance, very little is known about the molecular basis of these mechanisms. The present study was thus designed to investigate the molecular mechanisms implicated in the control of proliferation in the human placenta. We used immunohistochemistry to study the expression of two cell-cycle controlling molecules with opposing effects: the cell-cycle inhibitor, p27, which belongs to the Kip/Cip family of CDK inhibitors and can mediate G1 arrest, and cyclin E, a G1-cyclin esential for G1/S progression. Expression was studied throughout pregnancy in a total of 41 normal human placental samples. In addition, immunohistochemistry for Ki-67 was performed as a control for proliferation. The cell-cycle inhibitor p27 was expressed in the differentiated, non-dividing syncytiotrophoblast, while expression of cell-cycle promoter cyclin E was localized to the nuclei of the cytotrophoblast and correlated well with expression of Ki-67. No cyclin E expression was observed in the syncytiotrophoblast. In conclusion, strong expression of the cell-cycle inhibitor p27 and absence of expression of cyclin E in the syncytiotrophoblast might represent an important control mechanism in placental proliferation. This differentiates it from the proliferation of malignant tumours, where p27 has been shown to be frequently downregulated while cell cycle promoters are overexpressed.

Cell Cycle↗
PubMedDate not supplied

Quantitative assessment of HER-2/neu protein concentration in breast cancer by enzyme-linked immunosorbent assay.

PURPOSE: The HER-2/neu protein (p185) has become a promising target for antibody therapy in breast cancer. We tested the feasibility of a quantitative approach for HER-2/neu testing based on the analysis of tumor tissue extracts by an enzyme-linked immunosorbent assay (ELISA). EXPERIMENTAL DESIGN: Tumor tissue extracts of primary human breast cancers (n=124) were prepared using a triton-based buffer. HER-2/neu concentration was quantified by ELISA. Paraffin-embedded tissue sections of the same tumors were analyzed by immunohistochemical staining applying the monoclonal HER-2/neu antibody TAB 250 (n=124) and by chromogenic in situ hybridization (CISH) (n=73). RESULTS: Concentrations of p185 in tissue extracts determined by ELISA varied from 1 to 927 ng per mg protein with a median of 25 ng/mg protein, whereas normal breast tissue showed values from 0.4 to 5.5 ng/mg with a median of 2.2 ng/mg (p<0.0001, Mann-Whitney U test). A significant correlation between p185 concentration and immunohistochemical staining was observed (p<0.0001, Kruskal-Wallis test). In addition, p185 concentration measured by ELISA was correlated with the degree of HER-2/neu gene amplification determined by CISH. HER-2/neu-amplified tumors had significantly higher p185 concentrations (median value 181 ng/mg protein) than non-amplified tumors (median value 20 ng/mg; p<0.0001, Mann-Whitney U test). CONCLUSIONS: ELISA-based measurement of HER-2/neu protein concentration in breast cancer tissue extracts is feasible and provides quantitative results for p185 protein concentrations that correlate closely with HER-2/neu immunoscore and gene amplification.

Antibodies, Monoclonal↗