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A Schiesser

Publications and source records attributed to A Schiesser.

29 records · Page 2Linked to original sources
PubMed1987

Experimental osteoinduction in rats: collagen-apatite versus osteogenin-containing gelatine.

An experimental study in rats was done to investigate the bone-regenerating properties of collagen apatite (Collapat) and to compare it with osteoinduction dependent on osteogenin-containing gelatine (OCG). The test substances were implanted orthotopically (calvarial defect--7 mm in diameter) and heterotopically (paravertebral muscles, abdominal muscles). The results were evaluated histologically and enzymatically (alkaline phosphatase). Collapat caused neither osteoinduction in the heterotopic site nor healing of the bone defects. Foreign body reaction without new bone formation was encountered. OCG implantation leads to new bone formation in the muscles within 3 weeks, associated with a significant increase in alkaline phosphatase activity, and to extensive new bone formation in the calvarial defect within 4 weeks. The defects did not heal if left empty. The value of clinical application of Collapat appears to be doubtful. Osteoinduction with OCG requires further experimental investigation.

Animals↗
PubMed1986

Cellular (thrombocytes, granulocytes) effects of proteinase inhibitors--gabexylate, gabexate mesilate (FOY) and aprotinin.

Because of the involvement of proteinases in the activation mechanism of thrombocytes and granulocytes, the effect of proteinase inhibitors was tested. To document cell activation we used thrombocyte and granulocyte aggregation. Chemiluminescence and superoxide production were used as parameters for the release of activated oxygen compounds, and lysozyme as a marker of lysosomal enzyme release. FOY and aprotinin inhibited all but not arachidonic acid thrombocyte aggregation. Only aprotinin diminished granulocyte responses to various stimuli, while FOY was without effect at concentration less than 100 microM.

Aprotinin↗
PubMed1986

Morphometric studies on wound healing after systemic administration of adriamycin and local application of fibrin sealant. Application of a new wound healing model using spongiosa implants.

For investigations on the development of regenerative granulation tissue in wound healing a new model using bone spongiosa ("Kieler Spongiosa") implants is presented. Particular attention was devoted to developing a model which permits studies on wound healing without disturbance by foreign body reaction and infections. Two test groups of rats received four blocks of "Kieler Spongiosa" each in a symmetrical fashion in a paramedian region underneath the dorsal skin. The spongiosa blocks had previously been treated with glutaraldehyde to achieve cross-linkage of the collagenous structures of the surfaces of the spongiosa trabeculae. After one week (group 1) and two weeks (group 2) the animals were sacrificed. The spongiosa blocks were removed, fixed and evaluated in layered serial sections after decalcification. Two blocks which had been removed randomly from the back and front served for morphometric determination of the total volume of bony substance and the developed granulation tissue. Moreover, the cellular composition of the granulation tissue was morphometrically examined with regard to its content of capillaries, granulation tissue cells and inflammatory cells. The two other blocks were examined for DNA and hydroxyproline content of granulation tissue. Comparison of the two experimental groups yielded marked differences in spongiosa space infiltrated by granulation tissue and its composition. Our model was used to assess the influence of systemic administration of adriamycin and/or local application of a fibrin sealant system on granulation tissue formation and its morphologic structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Aggregation, chemotaxis, and chemiluminescence of canine granulocytes. Studies utilizing improved cell preparation techniques.

Wishing to extrapolate in vitro observations of granulocyte function and pharmacology made with human cells to animal models of diseases in which we believe granulocyte stimulation to play a major role, we examined techniques for preparation of canine granulocytes and conducted a survey of the function and pharmacology of those cells. Isotonic density gradients of Percoll proved a simple and highly satisfactory method of preparation. Canine granulocytes in most respects paralleled human cells in function and pharmacology, except that canine cells lacked receptors for formylated oligopeptides and resisted them as stimuli; canine plasma contained a heat-labile inhibitor of canine PMN aggregation, oxidative metabolism, and myeloperoxidase release; canine PMNs were not inhibited in aggregation by protease inhibitors such as aprotinin; canine response to ibuprofen and steroids was more variable than that of human cells, and synergy between those agents was less readily demonstrated; heterologous stimulation (canine cells by human C5a or vice versa) led to a different time course and maximum response from those observed in the homologous systems. Canine granulocytes were readily marked with indium-111, and functioned normally in vitro and survived well in vivo after marking. We conclude that the dog is a suitable animal for studying the role of stimulated PMNs in disease, as long as the observed differences are taken into account in experimental design and data interpretation.

Animals↗