Biomedical subjects

T Brückner

Publications and source records attributed to T Brückner.

7 recordsLinked to original sources

PubMed2006

Radio-guided surgery for persistent differentiated papillary thyroid cancer: case presentations and review of the literature.

BACKGROUND AND AIMS: Persistent differentiated papillary thyroid cancer following radical locoregional surgery with metastases is an indication for limited reoperation or radioiodine therapy. Following injection of radioiodine, radio-guided surgery with application of an intraoperative gamma probe offers detection of metastases not seen by conventional imaging and control of completeness of resection. PATIENTS/METHODS: We demonstrate four patients with locoregional metastases, two of them with additional distant metastases of papillary thyroid cancer following radical neck surgery. Postoperative radioiodine scans demonstrated persistent ipsilateral or contralateral cervical and mediastinal lymph node and isolated rib metastases. RESULTS: Radio-guided surgery (RGS) leads to complete clearance of persistent lymph node metastases by limited recurrent neck surgery, resection of metastases not seen by conventional imaging and control of complete mediastinal lymph node dissection. Post-RGS scans allowed early diagnosis of occult diffuse or nodal pulmonary metastases in two patients. At last follow-up, 23 to 48 months following RGS and radioiodine therapy, there was no evidence of disease. CONCLUSIONS: Radio-guided surgery is an additive surgical technique with low morbidity in selected patients with persistent thyroid cancer individualizing tumor therapy options in multimode oncological therapy.

Adolescent↗

PubMed2005

[Reoperation for thyroid cancer].

Reoperation for thyroid cancer needs to consider patient-, tumor- and therapy-related aspects as well as present diagnostic results. Reoperation because of thyroid remnants, persistence of the primary tumor and lymph node metastasis (completion surgery) has to be distinguished from reoperation due to locoregional recurrence (primary tumor, lymph nodes). The primary surgical strategy should avoid the need for reoperation. The extent of reoperation is related to the extent of primary surgery, stage, and distant metastasis. The timing and indication of reoperation for differentiated thyroid carcinoma in an interdisciplinary multimodal treatment setting depends on diagnostic radioiodine scans and radioiodine therapy. Long-term, recurrence-free survival is achieved by sufficiently radical surgery with acceptable morbidity, including all additive or adjuvant treatment options.

Disease Progression↗

PubMed2000

Comparison of rigid and elastic matching of dynamic magnetic resonance mammographic images by mutual information.

The present study aims at (i) the evaluation of the performance of a rigid and of an elastic matching algorithm for the coregistration of dynamic magnetic resonance (MR) images visualizing the female breast, and (ii) the evaluation of the mutual information (MI) as a matching criterion. To this end, ten patient data sets were analyzed. The comparison was performed with respect to the achieved increase in the MI and by visual inspection of the dynamic image series in a continuous film sequence ((cine mode). In most cases, the achieved increase in MI by elastic image registration is much higher than that achieved by rigid registration. Only for three of the ten data sets could the MI be increased by rigid image registration to a similar or even larger degree than by elastic image registration. Taking into account the results of the visual inspection of the rigid and elastic matched data sets, however, the elastic match leads to equal or better results for all data sets. Therefore, elastic matching is the gold standard for the registration of dynamic MR mammographic images of the female breast. The comparison of the increase in MI and the visual inspection further shows that the visual impression agrees in most cases with the result of the calculation of the MI. Therefore, the MI proves to be a suitable matching criterion for the type of data sets studied.

Algorithms↗

PubMed1997

Sensitivity enhancement of optical immunosensors with nanoparticles.

In recent years, several optical sensor techniques have been developed for the direct monitoring of biomolecular recognition processes at the surface of a sensor chip. Applications of these immunosensors for the determination of substances in serum could be demonstrated only for a few analytes due to the lack of sensitivity. Beside nonspecific binding of serum components to the sensor surface, the analytical sensitivity of these sensors is limited by the molecular weight of the analyte, so that smaller analyte molecules give only a moderate sensor response. In order to enhance the sensor signal, the use of mass labels, such as latex particles, was proposed in the literature. However, detection limits comparable to those of conventional ELISA techniques could not be realized so far. We demonstrate the optimization of a "nanoparticle enhanced immunosensor assay" for the detection of thyroid stimulating hormone, with respect to the particle coating, size, and nonspecific binding. The developed prototype assay requires a sample volume of 225 microL and has a measuring range up to 35 mIU/L. For the first time, we obtained a detection limit of 0.03 mIU/L (0.1 pm), which is fully competitive to conventional ELISA techniques. The assay allows serum samples to be measured with good precision and dilution linearity. The sensor can be reused several times and shows an excellent correlation to a commercial enzyme immunoassay.

Antibodies↗

PubMed1994

[Andrologic variables for in vitro fertilization].

The purpose of the study was to identify semen parameters relevant for in vitro fertilization (IVF). A total of 151 ejaculates from 130 patients were analyzed. There was a significant association between successful IVF, high sperm concentration and good sperm motility. Progressive sperm motility correlated best with successful fertilization of oocytes (r = +0.427) and was the only parameter significantly linked to pregnancy. Very low values were sufficient for fertilization in vitro: a sperm concentration of 4.5 x 10(6)/ml and a progressive sperm motility of 20%. The results of analysis of fructose, citrate and neutral alpha-glucosidase as markers of seminal vesicle, prostate and epididymal functions were not different in fertilizing and non-fertilizing semen samples. Moderate increases in granulocyte elastase levels, between 250 and 1000 ng/ml, did not influence IVF. However, two patients with genital tract inflammation (PMN-elastase > 1000 ng/ml) did not fertilize despite excellent semen parameters. These results stress the importance of andrological factors for in vitro fertilization outcome.

Adult↗

PubMed1986

Analysis of T-T lymphocytes and T-accessory cell interactions using cloned T cells: MHC I restricted cloned T cells activate MHC II restricted T helper cells.

We evaluated the role of molecules of the major histocompatibility complex (MHC) involved in the cellular interactions of two T-cell clones by testing the effect of monoclonal antibodies on the responses of the clones in vitro. The two T-cell clones used in the study are specific for minor histocompatibility antigens and restricted to the H-2Kk. In the absence of exogenous IL-2 the clones require the presence of Ia+, Thy-1- accessory cells and of Thy-1+, Lyt-1+2- cells in the irradiated spleen cell suspension used as stimulator. It is also necessary that both the accessory cells and the T cells in the stimulator cell populations are recognized specifically by the clones. Monoclonal antibodies specific for the H-2K product inhibited the lytic effector function of the cytolytic clone. These antibodies when added to cultures of stimulator cells and clones inhibited also the proliferation of this clone and of a nonlytic clone. When antigen recognition was measured by the increase in sensitivity of the clones to IL-2 while confronted with uv-irradiated stimulator cells, both clones were blocked efficiently by anti-H-2K antibodies. Thus, these results suggest that the interaction of monoclonal antibodies with the restricting H-2K molecule is sufficient to block the recognition signal, a prerequisite for proliferation. In contrast, monoclonal antibodies specific for A alpha A beta and/or E alpha E beta had no effect on cytolysis or on restricted recognition. However, they inhibited the proliferative responses as efficiently as the H-2K specific antibodies. Inhibition by class II-specific antibodies was not abolished when stimulator cell populations were depleted of Lyt-2+ cells. The blocking effect, however, was reversed by the addition of IL-2. No inhibition was obtained with antibody specific for E alpha E beta when B10.A(4R) spleen cells, which do not express E alpha E beta, or when B10.A(4R) accessory cells, which were reconstituted with (BALB/c X B10.A(4R] F1 T cells, were used as stimulators. Stimulator cells heterozygous for H-2 could be inhibited by antibodies to the parental haplotype not encoded in the clones (H-2Kd). These and previous results suggest that H-2K-restricted minor histocompatibility antigen-specific recognition transmits an activating signal to the clones and to the stimulator cells. The clones probably are induced to express more IL-2 receptors. The stimulator T cells seem to interact through A alpha A beta and E alpha E beta molecules with syngeneic accessory cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1984

T cell clones interacting with accessory and T helper cells for a proliferative response.

The requirement for cell interactions in T cell activation has been studied with two continuously in vitro growing T cell clones. These clones are specific for minor histocompatibility antigens, are H-2K restricted, and one clone is functionally a cytolytic T lymphocyte. Both can proliferate when interleukin 2 is added to the cultures, but for continuous growth they require irradiated spleen cells carrying the specific minor histocompatibility antigen and the restricting H-2. In this study we show that for proliferation the clones require at least two cell populations in the stimulator spleen, one is a splenic-adherent cell (SAC), the other a T cell. The SAC are plastic adherent, Thy-1-, Ia+. The T cells are nylon wool nonadherent, Thy-1+, Lyt-1+2- and Ia-. Cell mixing experiments of stimulator cells (all were done with H-2-syngeneic cells), depleted of either SAC or T cells confirm the requirement for a specific interaction between these two cell types and the T clone. Neither SAC, syngeneic with the T clone when mixed with T cells of the stimulator type, nor T cells syngeneic with the clone added to stimulator SAC, can induce an optimal proliferative response. Such a response is obtained only if both cell types, SAC and T cells, are of the stimulating genotype. This suggests that, in addition to an interaction of clonal T cells with SAC, a specific recognition at the T cell level between T stimulator and T clone is necessary. The interaction of the T clones with stimulator SAC and T cells leads to an activation, mediated by antigen recognition, of all three cell populations. Since we also show that each of the stimulator cell types are impaired by ultraviolet light irradiation, we conclude that factor production by SAC and T helpers is the final prerequisite for clonal expansion.

Animals↗