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Biomedical subjects

A Papachrysanthou

Publications and source records attributed to A Papachrysanthou.

9 recordsLinked to original sources
PubMed1998

[Fractionated, interstitial postoperative HDR-/PDR-brachytherapy with intraoperatively placed probes--initial experiences with a new radiotherapy modality in treatment of recurrent or non-resectable colorectal carcinomas].

Twenty-eight patients with recurrent (82.1%) and/or noncuratively resected (71.4%) colorectal cancer underwent fractionated interstitial BT (20.1 Gy) by using median 5.6 (3-11) afterloading tubes placed directly on the tumor bed intraoperatively. HDR/PDR BT started 2-3 weeks after multivisceral resection (50%) and was combined with external beam radiation therapy in 96% and with chemotherapy (5-FU/Leucoverin) in 86% of the patients. Though the R0-resection rate before BT was only 28.6% multimodality treatment resulted in a local tumor control rate of 64.3%, a survival rate of 53.6%, and a tumor-free survival rate of 42.9%, in an average of 19.8 months (2-43 months) after BT.

Brachytherapy↗
PubMed1997

[Surgical oncology: possible methods for financing complex oncological therapy procedures].

The AOK Schleswig-Holstein actually finances the evaluation of treatment costs for the project "Operative Oncology". After the primary conceptual phase, the project will be financed for several years and will be accompanied by quality-control studies. In addition to the procedure of the BMG, the costs of psychological support/therapy as well as for new molecular biological tests for the detection of micrometastases are calculated. The reason for this calculation is that these additional costs might be included into a specific, oncological resource-based value system of payment.

Cost-Benefit Analysis↗
PubMed1996

Circumvention of natural killer cell and T-cell mediated allogeneic target killing with tacrolimus (FK506) in small bowel transplantation related graft-vs-host disease.

The role of simultaneous donor-specific transfusion of unprocessed cellular bone marrow (BM) together with solid organ transplantation, a postulated concept to achieve long-term graft acceptance, was investigated in an experimental setting of semiallogeneic transplantation of parental small bowel (SBTx) to F1 hybrids. The established graft-vs-host (GvH) model revealed that simultaneous transfer of SB/BM substantially enhanced GvH-mediated immune responses in recipient target organs, e.g. skin, gut, and liver. In comparison to isolated SBTx, animal survival decreased from 16.1 (+/- 0.9) to 10.1 (+/- 0.8) days after additional BM transfusion, P < 0.001. Severe tissue injury of GvH-susceptible target organs in the setting of simultaneous SB and BMTx was associated with significant changes in recruitment and tissue distribution of NKR-P1+ cells during the GvH-related proliferative immune response. Tacrolimus effectively suppressed these initial events and prevented recipient animals from clinically and histologically observed damage caused by GvH disease.

Animals↗
PubMed1996

In vivo depletion of NKR-P1 positive cells in the recipient prior to small bowel transplantation enhances graft-versus-host disease (GvHD) in the rat.

Recent evidence for major histocompatibility complex (MHC) class I antigen-directed recognition mechanisms of natural killer cells (NKs) have revived interests in investigating non-adaptive immune responses in the framework of solid organ transplantation. A semi-allogeneic rat model of heterotopic small bowel transplantation (HSBTx) from male DA parental to male F1 hybrid rats (DA x LEW) was established to investigate the role of host NKs to attenuate graft-versus-host (GvH)-mediated immunosuppression and tissue injury. By use of anti-NKR-P1 monoclonal antibody (mAb) 3.2.3, host NKs were depleted effectively in vivo after triple intraperitoneal injection prior to HSBTx. In contrast to non-depleted animals, an initial lack of NK activity in F1 hosts significantly decreased the mean survival (P < 0.01) and substantially enhanced graft-versus-host disease (GvHD)-related damage to lymphoid and non-lymphoid target organs. These findings emphasize the important immunoregulatory role of host NKs during the early onset of GvHD.

Animals↗
PubMed1996

Correlation between graft-versus-host induced immunosuppression and host natural killer cell activity in small bowel transplantation.

The occurrence of graft-versus-host disease (GvHD) following small bowel transplantation (SBTx) can be tuned by the recipient's initial natural killer (NK) cell activity, which modifies the immunogeneic balance between donor and host immunocompetent cells. This study was aimed to investigate the role of host NK cells on the incidence and severity of GvHD following SBTx. Intraperitoneal administration of 50 microl ascites fluid of the highly specific anti-NKR-P1 monoclonal antibody (mAb) 3.2.3 into F1 recipient animals on three consecutive days prior to SBTx was performed to suppress NK activity in F1 hybrids. In vivo treatment with 3.2.3 mAb effectively depleted recipient NK activity for at least 10 days in spleens and mesenteric lymph nodes of F1 hosts. In contrast to nontreated F1 recipients, all 3.2.3 mAb-pretreated F1 animals suffered from severe signs of GvHD, and the mean survival time was decreased significantly from 16.0 +/- 0.9 days to 11.0 +/- 0.8 days (p < 0.01) in nontreated and NKR-P1-depleted F1 animals, respectively. Other sequelae included earlier onset of GvH manifestations, pronounced damage of primary and secondary lymphatic organs, substantial increase in spleen index, and lower CD4(+)/CD8(+ )ratios over the course of progressing GvHD. Our results underline the important immunoregulatory role of NK cells as a first defensive line acting on the alloreactivity of donor-derived immunocompetent cells in this model of solid organ transplantation.

Animals↗