Kristian Koller

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The shape, the typical orientation, and the average size of mineral crystals in different types of mineralized tissues were investigated by means of small-angle x-ray scattering (SAXS). To rule out eventual artifacts due to sample preparation, four different standard preparation techniques were used and a comparison showed that the SAXS results were(More)
The mechanism of calcification in bone and related tissues is a matter of current interest. The mean size and the arrangement of the mineral crystals are important parameters difficult to obtain by electron microscopy. Furthermore, most studies have been carried out on poorly calcified model systems or chemically treated samples. In the work presented here,(More)
The effect of the immunosuppressive agent cyclosporine A (CsA) on the resorption of neonatal mouse calvaria was examined in vitro. CsA, at concentrations of 10(-7) to 3 X 10(-5) M, inhibited bone resorption produced by 10(-8) M parathyroid hormone, 3 U/ml of mouse recombinant interleukin-1,5 X 10(-7) M prostaglandin E2, 14 U/ml of thrombin, 5 micrograms/ml(More)
The clinical effects of thyroid hormones on bone in hypo- and hyperthyroidism are well known but their fundamental role in the regulation of bone remodeling is still poorly understood. In this review the current literature is summarized and experimental data from our laboratory are presented. The direct stimulation of bone resorption by thyroid hormones in(More)
Production of the osteolytic arachidonic acid metabolites, prostaglandin (PG) E2, PGI2 and PGF2 alpha, by neonatal mouse calvariae was quantitated by gas chromatography/mass spectrometry. Mouse recombinant interleukin 1 (rIL-1) raised medium levels of PGE2 and PGI2 (measured as 6-keto-PGF1 alpha) in the dose range tested (1.0-10.0 U/ml culture medium),(More)
The objective of this study was the development of an assay based on suppression of endogenous prostaglandin synthesis in cultured neonatal mouse calvaria for evaluation of the biopotency of nonsteroidal anti-inflammatory drugs in bone. In preliminary trials, osteolytic activity due to spontaneous prostaglandin production over a 72 h culture period was(More)
The adenylate cyclase activator forskolin (1-10 mumol/L) inhibited 45Ca release from parathyroid hormone (PTH; 10 nmol/L) stimulated prelabeled neonatal mouse calvaria in short term culture (24 h). This effect of forskolin was potentiated by rolipram, Ro 20-1724, and isobutyl-methylxanthine, three structurally different inhibitors of cyclic AMP(More)
A role of gamma-interferon in the bone remodeling process can be implicated from its interference with bone resorptive processes in cultured neonatal mouse calvaria. The immune interferon is an efficient inhibitor of endogenous prostaglandin synthesis, particularly after stimulation by thrombin or arachidonic acid, and, in addition, has a calcitonin-like(More)
The bone-resorbing effects of thrombin and thyroxin, two agents that stimulate resorption in neonatal mouse calvaria by prostaglandin-dependent mechanisms, were examined in cultures of fetal rat limb bones. Thrombin produced maximal resorption in the limb bone cultures at a concentration of 100 U/ml when bones were cultured in BGJ supplemented with 1 mg/ml(More)
The present study compares the effects of calcitonin (CT) and interferon gamma (IFN-gamma) on the size, distribution, and ultrastructure of osteoclasts in cultured neonatal mouse calvaria. The number and cross-sectional area of osteoclasts in cultured bones was increased by the addition of parathyroid hormone (PTH) to the culture medium for 24-48 h.(More)