Liebe und Freundschaftsliebe als Voraussetzung für ein glückliches Leben und eine gelingende Gemeinschaft ­ Positionen aus der Philosophie der Antike.

The broad variety of concepts of love and friendship can be demonstrated as early as in ancient philosophy. Two fundamental and opposing categories emerge: asymmetry and symmetry in the relationship between two persons. While asymmetrical forms of love carry the potential for non-fulfilment and the resulting individual despair, symmetrical forms of love and mutual friendship as formulated since Aristotle, offer the possibilities of an equivalent and equal relationship of mutual exchange on a level playing field. Thus, they not only form a prerequisite for a happy life of individuals, but also the basis for a successful and just social community.

Influence of Different Antioxidants on X-Ray Induced DNA Double-Strand Breaks (DSBs) Using γ-H2AX Immunofluorescence Microscopy in a Preliminary Study.

BACKGROUND: Radiation exposure occurs in X-ray guided interventional procedures or computed tomography (CT) and γ-H2AX-foci are recognized to represent DNA double-strand breaks (DSBs) as a biomarker for radiation induced damage. Antioxidants may reduce the induction of γ-H2AX-foci by binding free radicals. The aim of this study was to establish a dose-effect relationship and a time-effect relationship for the individual antioxidants on DSBs in human blood lymphocytes. MATERIALS AND METHODS: Blood samples from volunteers were irradiated with 10 mGy before and after pre-incubation with different antioxidants (zinc, trolox, lipoic acid, ß-carotene, selenium, vitamin E, vitamin C, N-acetyl-L-cysteine (NAC) and Q 10). Thereby, different pre-incubation times, concentrations and combinations of drugs were evaluated. For assessment of DSBs, lymphocytes were stained against the phosphorylated histone variant γ-H2AX. RESULTS: For zinc, trolox and lipoic acid regardless of concentration or pre-incubation time, no significant decrease of γ-H2AX-foci was found. However, ß-carotene (15%), selenium (14%), vitamin E (12%), vitamin C (25%), NAC (43%) and Q 10 (18%) led to a significant reduction of γ-H2AX-foci at a pre-incubation time of 1 hour. The combination of different antioxidants did not have an additive effect. CONCLUSION: Antioxidants administered prior to irradiation demonstrated the potential to reduce γ-H2AX-foci in blood lymphocytes.

Regeneration in chronic sialadenitis: an analysis of proliferation and apoptosis based on double immunohistochemical labelling.

The understanding of regeneration in salivary glands as a finely tuned balance of cellular proliferation, differentiation and apoptosis has been limited by the difficulty of identifying proliferating cells. This has been overcome in the present investigation by double immunohistochemical labelling for the proliferation-associated antigen Ki67 and for different cell-type-specific antigens applied to 8 specimens of normal parotids and 16 specimens of chronic parotid sialadenitis with particular reference to acini and intercalated ducts. In comparison with low baseline rates of proliferation in normal parotids, proliferative indices were significantly increased in chronic sialadenitis in mature acinar cells, intercalated ductal cells and myoepithelial cells without evidence of proliferation by an additional population of cells. In accordance with findings in glands of experimental animals, the present data do not support the previously postulated concept of regeneration of acini and intercalated ducts by a hypothetical population of uncommitted ductal stem cells. The demonstration of a profound capacity for intrinsic glandular regeneration from differentiated cells represents a biological basis for the good results obtained from conservative therapy of chronic sialadenitis and offers hope for novel therapies designed to reconstitute impaired salivary flow.

A morphogenetic concept of salivary duct regeneration and metaplasia.

The exact mechanisms of physiological regeneration and of metaplastic processes of the salivary duct have not been definitely established, although regeneration from a putative uncommitted stem cell population has long been favored. In the present study, double immunohistochemical labeling for Ki 67 and alpha-actin or different cytokeratin subtypes, respectively, made possible an exact localization and quantification of cellular proliferation in the regular salivary duct and in different types of metaplasia. Our data demonstrate a baseline proliferative capacity in all five cell types of the salivary duct. Luminal secretory cells of the acinus and intercalated duct regenerate independently from myoepithelial or basal cells. In contrast, the renewal of oxyphilic cells in the striated and excretory duct is maintained by proliferation and differentiation of basal cells. The great majority of metaplasias develops from uncommitted, Bcl-2 positive basal cells of striated/excretory ducts which possess an enormous capacity for pluridirectional morphogenetic differentiation. Despite this important role of basal cells, our findings demonstrate that all cell types principally have to be considered as potential progenitor cells for salivary gland tumors. The improved insight into regenerative and metaplastic processes of the salivary duct may contribute to a better understanding of the complex formal carcinogenesis.

Differential diagnosis of salivary acinic cell carcinoma and adenocarcinoma (NOS). A comparison of (immuno-)histochemical markers.

A correct histologic differential diagnosis between salivary acinic cell carcinoma (ACC) and adenocarcinoma not otherwise specified (AC-NOS) is highly relevant because of the strikingly different biologic behavior and related therapeutical strategies. The distinction between both tumor types can be difficult because of an enormous variation in histologic appearance, with either type showing partially overlapping morphologic features. Owing to a lack of approved markers, the expression of PAS-staining, alpha-Amylase, alpha-1 Anti-trypsin, cytokeratin (CK)-subtypes 7/18 and Ki-67 was evaluated in 16 cases of ACC and 16 cases of AC-NOS. CK 7 is identified as the most reliable marker with strong positivity in AC-NOS, and complete or preponderant negativity in ACC. The characteristic membranous staining pattern of CK 18 in ACC, in contrast to a diffuse cytoplasmic pattern in AC-NOS, proved to be an additional valuable criterion. PAS and alpha-Amylase are only of little value when ACC is diagnosed, as many cases are only faintly positive or completely negative. The proliferation index (Ki-67) proved to be significantly higher in AC-NOS; however, the diagnostic usefulness is limited by a relevant overlap. In conclusion, we recommend CK 7 and 18 as the most valuable markers in cases with difficult differential diagnosis between ACC and AC-NOS.