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Biomedical subjects

W Timmermann

Publications and source records attributed to W Timmermann.

At least 73 records · Page 4Linked to original sources
PubMed1992

Rejection prophylaxis with interleukin-2 receptor antibody BT 563: mechanisms of action on human cells.

We investigated the in vitro immunosuppressive effect of BT 563, a monoclonal antibody, against the alpha-chain of the human interleukin-2 (IL-2) receptor (p 55), which has been used to prevent transplant rejection in several clinical trials. We also measured the proliferative T cell alloresponse and pCTL frequencies of BT563-treated kidney transplant patients. In mixed lymphocyte cultures BT 563 caused a reduction of T cell proliferation to about 50%. This could not be reversed by the addition of exogenous IL-2. A more effective reduction (80%) was seen in the generation of cytotoxic T cells from CML cultures and at the clonal level. The specific T cell response after preincubation with antigen and BT 563 was not reduced so that BT 563 did not induce tolerance. The in vitro findings indicated that BT 563 had a significant but incomplete immunosuppressive effect. This correlated with the clinical course and ex vivo analysis of PBL from BT 563-treated patients after kidney transplantation.

Antibodies, Monoclonal↗
PubMed1990

Development and perspectives of experimental pancreas transplantation in the rat.

Whole organ pancreas transplantation in the rat was first described by Sun Lee in 1972. Since that time the basic technique has been modified in several ways and this model can now be used for a variety of experiments. Various techniques for transplantation and representative results of functional and immunological experiments are summarized.

Animals↗
PubMed1989

[Perineal resection of rectal prolapse in risk patients].

A method for perineal resection of rectal prolapse in high-risk patients which uses a circular stapling device was evaluated. After the external rectal layer was dissected 2 cm above the dentate line, the sigmoid colon was mobilized distally as far as possible. An anastomosis was then performed with the stapler under gentle tension on the sigmoid colon. None of the eight patients died; mucosal prolapse recurred in one patient. Continence was improved in six of the eight patients.

Colon, Sigmoid↗
PubMed1989

[First successful clinical small intestine transplantation. Tactics and surgical technic].

A case of successful clinical small bowel transplantation is demonstrated. A segment of 60 cm of jejunum and ileum has been harvested from the sister of the recipient and has been brought in heterotopic position in the first operative step. It was anastomosed to the recipient's GI-tract 6 weeks later. This procedure has the advantage that the graft can recover from ischemic damage in heterotopic position and that an immunological steady state can be achieved. This case of successful clinical small bowel transplantation offers a new causal therapy for patients with short gut syndrome.

Adult↗
PubMed1985

[Models and perspectives of pancreas transplantation in the rat. I. Comparison of various transplantation models in the syngeneic system].

Pancreas transplants were grafted in rats using five different microsurgical techniques. Three of the techniques allowed exocrine drainage, namely pancreaticoduodenal transplantation, grafts with a duodenal patch, and grafts with exocrine drainage via a Roux-en-y-loop. Segmental transplants in which the duct system was ligated or occluded with Ethibloc were used as models without exocrine drainage. Donors and recipients were Lewis rats. Diabetes was induced in the recipients with streptozocin. Regular measurements of serum glucose and body weight served as functional controls. At the end of the observation period, the grafts were examined macroscopically and microscopically. Basically, all types of grafts allowed normalization of the blood sugar level. In grafts with ligated or occluded ducts, however, we observed functional failure due to fibrosis or abscesses. It became obvious that all grafts without exocrine drainage are subject to alternative processes that lead to the loss of exocrine tissue, to proliferation of the pancreatic ducts and to morphological changes in the islets. In successfully drained grafts, the morphology of the organ is lastingly preserved. In the rat model the most reliable management of exocrine drainage is afforded by pancreaticoduodenal grafts.

Animals↗
PubMed1985

[Models and perspectives of pancreas transplantation in the rat. II. Course of rejection of pancreaticoduodenal transplants of various histoincompatibility and the effect of temporary therapy with cyclosporin (Sandimmun)].

Pancreaticoduodenal grafts were transplanted into streptozocin-induced diabetic recipients. Recipients of syngeneic grafts survived long term with functioning grafts. To investigate the rejection reaction in pancreaticoduodenal allografts, the organs were grafted in an MHC compatible but non-MHC incompatible strain combination (AS----LEW) and in a combination that is both MHC and non-MHC incompatible (DA----LEW). The functioning times were 12.4 +/- 4.0 days in the AS----LEW group and 8.2 +/- 0.6 days in the DA----LEW group. A histologic study of the course of the rejection process showed that first the exocrine portion of the grafts, then the endocrine tissue, and finally the duodenum was destroyed. After the recipients of allografts were treated with an oral dose of 15 mg/kg/day Ciclosporin (Sandimmun) for 14 days p.op., the functioning times of the grafts increased to 47.5 +/- 14.4 days in the AS-LEW group and 26.0 +/- 0.5 days in the DA-LEW group. Histologic investigations showed that during the period in which Ciclosporin was given, only perivascular round cell infiltrates appeared with no visible destruction of the graft. After discontinuation of the medication basically the same histologic alterations occurred as in untreated allografts, however with a delay.

Animals↗