Maintenance of ATP favours apoptosis over necrosis triggered by benzamide riboside.

A new synthetic drug, benzamide riboside (BR) exhibited strong oncolytic activity against leukemic cells in the 5-10 microM range. Higher BR-concentrations (20 microM) predominantly induced necrosis which correlated with DNA strand breaks and subsequent depletion of ATP- and dATP levels. Replenishment of the ATP pool by addition of adenosine prevented necrosis and favoured apoptosis. This effect was not a pecularity of BR-treatment, but was reproduced with high concentrations of all trans-retinoic acid (120 microM) and cyanide (20 mM). Glucose was also capable to suppress necrosis and to favour apoptosis of HL-60 cells, which had been treated with necrotic doses of BR and cyanide. Apoptosis eliminates unwanted cells without affecting the microenvironment, whereas necrosis causes severe inflammation of surrounding tissues due to spillage of cell fluids into the peri-cellular space. Thus, the monitoring and maintenance of cellular energy pools during therapeutic drug treatment may help to minimize nonspecific side effects and to improve attempted drug effects.

Equine articular chondrocytes on MACT scaffolds for cartilage defect treatment.

Treatment of cartilage defects poses challenging problems in human and veterinary medicine, especially in horses. This study examines the suitability of applying scaffold materials similar to those used for human cartilage regeneration on equine chondrocytes. Chondrocytes gained from biopsies of the talocrural joint of three horses were propagated in 2D culture and grown on two different scaffold materials, hyaluronan (HYAFF®) and collagen (BioGide®), and evaluated by light and electron microscopy. The equine chondrocytes developed well in both types of materials. They were vital and physiologically highly active. On the surface of the scaffolds, they formed cell multilayers. Inside the hyaluronan web, the chondrocytes were regularly distributed and spanned the large scaffold fibre distances by producing their own matrix sheath. Half-circle-like depressions occasionally found in the cell membrane were probably related to movement on the flexible matrix sheath. Inside the dense collagen scaffold, only single cells were found. They passed through the scaffold strands by cell shape adaptation. This study showed that the examined scaffold materials can be used for equine chondrocyte cultivation. Chondrocytes tend to form multilayers on the surface of both, very dense and very porous scaffolds, and have strategies to span between and move in large gaps.

Histochemical characterization of the adhesive organ of three Idiosepius spp. species.

An adhesive organ is a prominent characteristic of the genus Idiosepius. Histological, histochemical and ultrastructural methods were applied to elucidate the nature of secretion of the epithelial cells of three Idiosepius species. The adhesive organs of Idiosepius biserialis and Idiosepius pygmaeus consist of five distinct cell types that can be distinguished morphologically and by the composition of their secretions. Histochemical analysis revealed that three cell types contain different sugar units and basic proteins, whereas the interstitial cells lacked secretory material. Acidic and sulfated substances were absent in Idiosepius secretions. The adhesive organ, but not the secretory material of the glandular cells, contained O-linked oligosaccharides. The histochemical analysis of the secretory products suggested that adhesion and release are not effected by a "duo-gland" adhesive system as in Euprymna scolopes. Idiosepius presumably uses a transitory adhesion, perhaps induced by secretion of a highly viscous gel. Release might be caused by contraction of the mantle musculature and/or chemical release mechanisms such as dilutors or enzymes.