2,799 research outputs found
Monoclonal antibodies against human astrocytomas and their reactivity pattern
The establishment of hybridomas after fusion of X63-Ag8.653 mouse myeloma cells and splenocytes from mice hyperimmunized against human astrocytomas is presented. The animals were primed with 5 × 106 chemically modified uncultured or cultured glioma cells. Six weeks after the last immunization step an intrasplenal booster injection was administrated and 3 days later the spleen cells were prepared for fusion experiments. According to the specificity analysis of the generated antibodies 7 hybridoma products (MUC 7-22, MUC 8-22, MUC 10-22, MUC 11-22, MUC 14-22, MUC 15-22 and MUC 2-63) react with gliomas, neuroblastomas and melanomas as well as with embryonic and fetal cells but do not recognize non-neurogenic tumors. The selected monoclonal antibodies (McAbs) of IgG1 and IgG2a isotypes are not extensively characterized but these antibodies have been demonstrated to be reactive with a panel of glioma cell lines with varying patterns of antigen distribution. Using the McAbs described above and a series of cryosections of glioma biopsies and paraffin sections of the same material as well as glioma cultures established from these, variable antigenic profiles among glioma cell populations could be demonstrated. From these results it is evident that there is not only a distinct degree of antigenic heterogeneity among and within brain tumors, but also that the pattern of antigenic expression can change continuously. Some of the glioma associated antigens recognized by the selected antibodies persist after fixation with methanol/acetone and Karnovsky's fixative and probably are oncoembryonic/oncofetal antigen(s). The data suggest that the use of McAbs recognizing tumor associated oncofetal antigens in immunohistochemistry facilitates objective typing of intracranial malignancies and precise analysis of fine needle brain/tumor biopsies in a sensitive and reproducible manner
On the relation of nonanticipative rate distortion function and filtering theory
In this paper the relation between nonanticipative rate distortion function
(RDF) and Bayesian filtering theory is investigated using the topology of weak
convergence of probability measures on Polish spaces. The relation is
established via an optimization on the space of conditional distributions of
the so-called directed information subject to fidelity constraints. Existence
of the optimal reproduction distribution of the nonanticipative RDF is shown,
while the optimal nonanticipative reproduction conditional distribution for
stationary processes is derived in closed form. The realization procedure of
nonanticipative RDF which is equivalent to joint-source channel matching for
symbol-by-symbol transmission is described, while an example is introduced to
illustrate the concepts.Comment: 6 pages, 4 figures, final version submitted for publication at 12th
Biannual European Control Conference (ECC), 201
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