Biomedical subjects
Publications and source records attributed to G Matthes.
The possibility of the application demineralised human cortical substance with a particle size of 315 micron was investigated on the filling of artificial defects at the tibial diaphysis in rabbit. A clear induction of the bone healing was observed histologically on the transplant side already after 4 weeks and the absence of a periosseous callus formation radiologically.
Arterio-venous shunts of new allogenic, aldehyde-preserved, form-fixed saphena with silicone-coated inner surfaces were applied to the upper arms of seven children aged between four months and ten years. Two children died of open shunt, and two transplants underwent thrombosis, within a follow-up period of 27 months. The causes of death and thrombosis were in no way related to the transplant material. Infection, aneurysm, and stenosis did not occur.
A total of 114 vascular transplants of formaldehyde-preserved, form-fixed bovine vessels with silicone-coated inner surface were implanted to 113 dialysis patients and to one patient with asthma bronchiale. They were used as arteriovenous bridging grafts for punctures or parts of them and as arterial bridging grafts for repair. Included were A. glutealis in 43 instances as well as A. thoracica interna, V. glutealis and V. thoracica interna in 18 instances, and A. sacralis in 53 cases. Low early-thrombosis rates were recorded from all transplants. Transplants of A. glutealis and A. thoracica interna quite often exhibited spontaneous aneurysmatic enlargement in response to repeated puncturing. Fewer complications were recordable from transplants of A. glutealis, V. thoracica interna and A. sacralis.
Studies were conducted into the effects of various forms of flow reduction upon both pressure in shunt and functional properties of 134 arteriovenous bridging grafts on the upper arm for haemodialysis of deantigenised, form-fixed, preserved segments of varicose veins with silicone-coated inner surfaces. Strongest pressure reduction and best clinical results were obtained from composite grafts with a short, narrow segment on the inflow side.
The influence of antioxidative drugs on the cryopreservation of human bone marrow cells was studied. The viability of bone marrow cells was tested after freezing and thawing from--196 degrees C by the growth of GM-CFC in agar culture. The results suggest the ability of antioxidants to protect stem cells against damage caused by freezing and thawing. Addition of tocopherol or penicillin to a cryoprotective medium increases the number of surviving GM-CFC. From the colony-to-cluster ratio can be concluded that antioxidants especially protect more immature haematopoietic (colony forming) cells.
A report is presented on the first experiences gained after introducing a system for the reduction of pretransfusional diagnostics (BAB-system). By using this system at the University clinics of the Charité, Berlin, it was possible to lower the quotient of crossmatch/transfusion to 1.8 and to increase the availability of stored blood by 15%. So, the application of the BAB-system will lead to an increase of efficiency in compatibility tests prior to transfusion, thus contributing to an optimization in blood storage.
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An analysis is described which deals with the relation existing between those amounts of stored blood which are demanded and used in serological cross tests on the one hand and that transfused stored blood used in operations which can be planned in selected clinics on the other hand by accounting for the demanding parameters of 3 stored blood items and less and 4 stored blood items and more.
On the basis of experiences in storage which were gained in industry and pharmacy the health service is also looking for possibilities of increasing the effectiveness of its work. Particular difficulties are encountered in the field of keeping stored blood in a depot. Within the framework of a contract of co-operation concluded with the Department of Mathematics at the Humboldt-University in Berlin we made the attempt of improving the level of our depot of stored blood to such an extent that no incorrect amounts will occur, with the decay being reduced simultaneously. For this aim various possibilities indicated in literature were tested for their applicability. First conclusions were drawn for the Berlin University Clinic Charité.
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By using dimethylsulfoxide (0.7 mol/l) a technique of cryoconservation of thrombocyte concentrates was elaborated, with own material-technological possibilities being taken into consideration. In comparison to fresh thrombocytes the results of parameters tested in vitro reveal a mean functional ability of 50%. The survival time of cells stored in this way in vivo may be compared with fresh cells. On this basis HLA-typed single-donor pools could be established for clinical application.
Experiments were carried out on cryopreservation of rat hearts. Viability of hearts perfused with cryoprotectant containing solutions as estimated by a short-time connection of rewarmed hearts with the circulation of a recipient animal. ECG, contraction and reflow from the perfused heart were measured. The same method were carried out in hearts after hypothermic storage.
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