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Biomedical subjects

R Ewers

Publications and source records attributed to R Ewers.

At least 91 records · Page 5Linked to original sources
PubMed1986

The autoclaved autogenous bone graft as a re-implant. Results of animal experiments.

The use of autoclaved bone grafts was studied in animal experiments. First we checked the immunological response in inbred rats. No antigen-antibody reaction could be detected after syngenic and allogenic autoclaved bone grafting. The bone healing of autogenous autoclaved rib grafts of different length was tested in inbred dogs. After polychrome sequential marking we investigated the periosteal and endosteal osteogenic repair of the transplant-area using different histological techniques. Simultaneously we observed the slow destruction and lysis of the autoclaved graft. In our opinion the use of autoclaved autogenous bone graft is possible, under stable conditions, for immediate reconstruction of the mandible in tumour surgery.

Animals↗
PubMed1986

The autoclaved autogenous reimplant, an immediately replaced, mineral frame.

Due to our good experimental results with an immediate mandibular body-replacement after resections we report our clinical and histological findings of a 35 weeks-lasting transplantation of autoclaved bone. We could not confirm a "foreign body" reaction and absent bone-resorption by osteoclasts, described by Harding in 1957. During metal removal after the 28th week postoperatively we observed clinically a good incorporation of the graft and the histological evaluation of the 28th and 35th week specimens showed an excellent bony bridging of the osteotomy, non-irritant incorporation of the graft and a beginning remodelling of the mineral frame which had functioned as an immediate space retainer.

Bone Plates↗
PubMed1985

Experimental and clinical results of new advances in the treatment of facial trauma.

Theoretical considerations and photoelastic and mechanical experiments showed us the progression from metal wires to metal plates in different systems. In the midface there is no question about stabilization by miniplate systems. For mandibular fracture treatment, there is a discussion going on at present about the use of stable maxisystems versus less stable minisystems. Our clinical experience of 15 years indicates that there is no further demand for strict stable fixation of mandibular fractures, and we were encouraged to use less stable systems with similar good results, as our follow-up and statistical evaluation showed. To continue the simplification of osteosynthesis methods we are performing experiments with resorbable materials. Early results show fracture healing comparable with that found with plate-and-screw systems. Our clinical experience has shown that there is no longer any question about the ability of stable fracture treatment by means of osteosynthesis. However, there still is the question of how functional such fracture treatment might be.

Animals↗
PubMed1985

[13-cis-Retinoic acid and spermatogenesis. Spermatological and impulse cytophotometric studies].

Twenty male volunteers with severe acne conglobata were treated orally over a period of 12 weeks with 1 mg isotretinoin (13-cis-retinoic acid) per kilogram body weight. Before and after therapy, as well as 12 weeks after the end of therapy, the semen was examined spermatologically and the spermatozoa DNS determined by impulse cytophotometry. The sperm density remained unchanged in the otherwise healthy patients, whereas patients with previous gonadal defects (unilateral cryptorchism, hypogonadism, varicocele) the sperm count rose significantly (P less than 0.05) at the end of therapy; 3 months later a reverse trend in the sperm density was noted. The percentage of morphologically normal spermatozoa was slightly reduced at the end of therapy; 12 weeks after completion of therapy it was significantly reduced (P less than 0.05). This could, however, be due to the short elimination half-life of 13-cis retinoic acid and have nothing to do with the drug. On impulse cytophotometry the spermatozoa DNS showed no significant changes. According to the results of the cytophotometric examination, contraceptive measures for men during treatment with 13-cis-retinoic-acid need not be made obligatory.

Acne Vulgaris↗