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C Körner

Publications and source records attributed to C Körner.

41 records · Page 3Linked to original sources
PubMed1991

High density of beta 2-adrenoceptors in a human keratinocyte cell line with complete epidermal differentiation capacity (HaCaT).

A non-tumorigenic keratinocyte cell line with complete epidermal differentiation capacity (HaCaT) was used in radioligand binding experiments to determine the number of beta-adrenoceptors. Intact cells were saturated with 3H-labelled (-)CGP-12177 (CGP), a hydrophilic non-selective beta-adrenergic antagonist as radioligand. In order to investigate the beta-adrenergic subtype selectivity, displacement experiments were performed with different antagonists and agonists. Binding of CGP to keratinocytes has been shown to be reversible and saturable and to have high affinity (Bmax = 114.0 +/- 8.8 fmol/10(7) cells with 6866 receptors/cell, KD = 0.095 +/- 0.017 nmol/l; n = 11). Beta-adrenergic antagonists inhibited binding yielding monophasic displacement curves. IC50-values (nmol/l) were: propranolol (non-selective) 1.68; CGP-12177 (non-selective) 1.08; ICI 118,551 (beta 2-selective) 2.92; bisoprolol (beta 1-selective) 1230; and CGP-20712 (beta 1-selective) 24,980. Agonists displaced CGP in the order isoprenaline greater than adrenaline greater than noradrenaline. We conclude that HaCaT cells express a high density of beta2-adrenoceptors providing a good model system to study adrenergic receptor mechanisms under reproducible experimental conditions in keratinocytes.

Binding, Competitive↗
PubMed1990

Radioligand binding characteristics of beta 2-adrenoceptors of cultured melanoma cells.

The existence of beta-adrenoceptors on intact cells of the human malignant melanoma cell line A-375 was investigated using the binding properties of the tritiated radioligand (-)-[3H]CGP-12177, a hydrophilic non-selective beta-adrenoceptor antagonist. Displacement experiments of the radioligand from its binding site were performed with antagonists and agonists to determine the beta-adrenoceptor subtype selectivity. The binding of (-)-[3H]CGP-12177 was saturable, of high affinity (KD = 0.025 nmol/l, n = 12) and was rapid and readily reversible. The maximal number of binding sites (Bmax) was 33.5 +/- 1.9 fmol/10(7) cells or 2018 +/- 114 receptors per cell. beta-adrenoceptor antagonists inhibited binding of the radioligand with monophasic displacement curves. IC50 values were (nmol/l): propranolol (non-selective) 2.82, alprenolol (non-selective) 2.0, ICI 118,551 (beta 2-selective) 3.5 and bisoprolol (beta 1-selective) 2200. Agonists inhibited binding in the order of potency of isoprenaline greater than adrenaline greater than noradrenaline. It is concluded that cells of the melanoma cell line A-375 contain a homogeneous population of beta 2-adrenoceptors.

4-Chloro-7-nitrobenzofurazan↗
PubMed1988

Plant life in cold climates.

Structural and functional features of plants from cold regions such as high mountain and tundra environments are characterized. Cold climates are not necessarily cold for plants at all times and influences of plant-growth form on canopy climate are substantial. Extreme low temperatures can cause temporal cessation of metabolic processes or partial tissue losses, but rarely represent an existential problem for plants native to cold regions. Low temperatures induce drastic changes in plant physiognomy and leaf anatomy, but dry matter allocation to the different plant compartments does not show a uniform trend. This suggests that generalizations of optimization and adaptation theories are not appropriate in this respect and that the functional importance of carbohydrate budgets is commonly over-estimated. Inconsistent with widespread beliefs, photosynthetic capacity in plants from cold regions is not essentially different from that in temperate regions, when comparable life forms are considered. Prevailing leaf temperatures exert minor limitations to seasonal photosynthetic carbon gain. Low temperatures come into play primarily in two ways: indirectly, via the length of the growing season and perhaps mineral nutrient availability, and directly, through influences on the growth process per se. Inherited slow or temporally restricted growth resembles an evolutionary response to long-term expectations of low resource availability. Within these genetic constraints the mitotic rate seems to be an essential point of action where low temperature determines the growth of an individual under respective local climates. Evidence is provided to support this view of an overruling significance of developmental processes in plant performance under cold conditions.

Climate↗
PubMed1982

[Treatment experiments with glucose-induced hyperglycaemia plus Clostridium-spores on the Jensen sarcoma of rats].

Investigations Jensen's sarcoma-bearing Wistar rats demonstrate the possibility to increase significantly the oncolytic effect of an apathogenic strain of Clostridium butyricum (5 x 10(8) spores of Cl. oncolyticum M 55 i.v.) by an artificial short time hyperglycaemia (achieved maximum blood level of glucose 28.87 +/- 8.05 mmol/l). The most impressive effect was observed after a repeated application of this combination at a distance of 7 days. Both the hyperglycaemia and the application of spores have a high tumour selectivity and a relatively good compatibility. The consequence for estimations of the LDH-, ALAT- and ASAT-activity in the judgment of the therapeutical tumours damage rate is discussed.

Alloxan↗