Biomedical subjects

T Luckenbach

Publications and source records attributed to T Luckenbach.

3 recordsLinked to original sources

PubMed2001

Multiple receptors mediate apoJ-dependent clearance of cellular debris into nonprofessional phagocytes.

Phagocytosis of apoptotic, senescent, and dying cells by macrophages is a well characterized process. More recently it has been shown that in addition to macrophages vital neighboring cells in the affected tissue participate in the cellular clearance. While scavenger receptors have been shown to mediate uptake into macrophages, it is poorly understood how cellular debris is internalized by nonprofessional phagocytes. We here analyze the endocytic activity of vital fibroblasts and epithelial cells exposed to cellular debris and membrane remnants. We show a mutual stimulation in the endocytosis of debris and apolipoproteinJ (clusterin) in these cells. Experiments using RAP (receptor-associated protein) to block ligand binding to LRP and megalin as well as studies in LRP- and megalin-deficient cells suggest that the uptake of apoJ and cellular debris is mediated by megalin, LRP, and yet unidentified internalization mechanisms.

Animals↗

PubMed2001

Toxicity of waters from two streams to early life stages of brown trout (Salmo trutta f. fario L.), tested under semi-field conditions.

The development of brown trout (Salmo trutta f. fario L.) in water of two differently polluted streams and in a control situation was monitored in order to get insights into the impact of anthropogenic chemical stressors on the reproductive success of this fish species indigenous to both streams. The test streams, situated in the south of Stuttgart, Germany, were the complexly polluted Körsch stream and the less polluted Krähenbach stream. Bypass systems connected to the streams and a laboratory control system were used for continuous exposure of early brown trout stages shortly after fertilisation up to the end of the embryonic development. Temperature and oxygen conditions were standardised in all test series in order to minimise unspecific effects. The examined endpoints were: (1) mortality, (2) developmental rate, (3) time course of hatching, (4) malformations, and (5) growth. A retarded development, reduced growth rates and higher mortality rates of Körsch stream water exposed embryos indicated an embryotoxic potential for the more polluted stream. High infection-related mortality rates of embryos suggested the presence of confounding factors also in the less polluted Krähenbach stream. In parallel to the exposure experiment, physicochemical and limnochemical parameters as well as concentrations of organic contaminants and heavy metals were monitored. Analytical data confirm the different degrees of pollution of both streams.

Animals↗

PubMed1991

[Opacity and opacity changes in composites].

The opacity of 5 self-curing and 11 light-curing composite resins was measured 24 hours after sample/preparation and after 6 months of storage (dry or in water) by means of an UV-visible spectrophotometer. The opacity of the investigated hybrid composite resins was between 47.3 and 62.4%. The opacity of the microfilled composite resins ranged from 48 to 64.4%. The opacity was not influenced by the polymerization time. The spectral opacity decreased with greater wavelengths, particularly in microfilled composite resins. All materials except Durafill, which became more translucent, were more opaque after 180 days of storage in water. Storage in water for 180 days caused greater changes of the opacity than dry storage for the same time. The opacity changes resulting from storage in water can be reduced by increasing the polymerization time.

Analysis of Variance↗