Certain proteins or activities are present in mitotic cells but not in interphase cells. These proteins may be synthesized or activated, or both, just prior to mitosis and are responsible for the breakdown of the nuclear envelope and the condensation of chromosomes. To learn more about the nature of these proteins, we raised monoclonal antibodies to mitotic cells. Spleen cells from mice immunized with a 0.15 M NaCl extract of synchronized mitotic HeLa cells were fused with SP2/0-Agl4 mouse myeloma cells, and hybrids were selected in medium containing hypoxanthine, methotrexate, thymidine, and glycine. Two different hybridoma clones secreting antibodies reactive with mitotic and meiotic cells from every species tested were isolated. Chromosomes as well as cytoplasm in mitotic cells reacted with the antibodies, as detected by indirect immunofluorescence. The proteins from mitotic cells were separated by electrophoresis in NaDodSO4/polyacrylamide slab gels, transferred to nitrocellulose sheets, and stained immunochemically. The two antibodies, designated MPM-1 and MPM-2, recognize a family of polypeptides with apparent molecular masses of 0.40 to >200 kilodaltons (kDa). Both antibodies reacted strongly with three polypeptide bands of 182 kDa, 118 kDa, and 70 kDa. Only mitotic cells exhibited the protein bands that were recognized by the antibodies. All these bands were found to be phosphoproteins as shown by 32P labeling and autoradiography and their removal by alkaline phosphatase treatment.The nucleus of a mammalian cell undergoes profound reorganization when the cell enters mitosis. The nuclear envelope breaks down, and the chromatin condenses into discrete chromosomes. Although the initiation of mitosis is dependent on both RNA and protein synthesis until 2 hr and 1 hr, respectively, before mitosis, the addition of inhibitors of RNA and protein synthesis to cells after these times does not affect either initiation or completion of mitosis (1, 2).The fusion of a mitotic cell with an interphase cell can induce nuclear envelope breakdown and premature chromosome condensation of the interphase nucleus (3). During this process, [3H]tryptophan-labeled proteins from mitotic cells labeled at G2 phase become associated with the prematurely condensed chromosomes, whereas the grain density on the metaphase chromosomes is not changed (4). Chromosome condensation and germinal vesicle (nucleus) breakdown can be induced in frog oocytes by the injection of extracts from mitotic but not interphase cells (5). The activity is labile to heat, sensitive to protease, insensitive to nuclease, and stabilized by phosphatase inhibitors and is found both in the cytoplasm and on the chromosomes of mitotic cells (6). These results suggest that certain nonhistone proteins, possibly phosphoproteins, of mitotic cells are not present in interphase cells. Al-Bader et al. (7) have reported the presence of such mitotic-specific proteins by using two-dimensional gel electrophoresis.The objective of this study was to raise monoclonal antib...

A 450-mg dose of TNX-901 significantly and substantially increased the threshold of sensitivity to peanut on oral food challenge from a level equal to approximately half a peanut (178 mg) to one equal to almost nine peanuts (2805 mg), an effect that should translate into protection against most unintended ingestions of peanuts.

Protein phosphorylation has been suggested as an important control mechanism for the events leading toward the initiation and completion of mitosis. Using a monoclonal antibody recognizing a class of phosphoproteins abundant in mitotic cells, we demonstrated the localization of a subset of these phosphoproteins to several discrete mitotic structures. Patchy immunofluorescence was present in the interphase nuclei, but a significant increase in nuclear immunofluorescence was apparent at prophase. Subsequent mitotic stages demonstrated that immunoreactive material was particularly apparent at microtubule organizing centers, namely, centrosomes, kinetochores, and midbodies. Intense centrosomal localization occurred at the prophase-prometaphase transition and persisted until the reformation of the nuclear membrane in early G1. The cytoplasm of mitotic cells also contained immunoreactive material in sharp contrast to interphase cells that exhibited no cytoplasmic fluorescent staining. Much of the diffuse immunofluorescent cytoplasmic material was removed by a brief lysis of the cells with 0.15% Triton X-100 prior to fixation. The localization of the remaining immunoreactive material after detergent lysis to mitotic microtubule organizing centers suggests that they contain phosphoprotein structural components important, perhaps, in the mitotic phase-interphase transition.The regulatory events controlling the initiation and completion of mitosis are poorly understood. It is apparent, however, that such varied cellular responses as reorganization of the microtubule network, chromosome condensation, centriole duplication, breakdown of the nuclear membrane, formation of the mitotic spindle, and cytokinesis must be coordinated closely for the cell to progress through mitosis.One possible mechanism for controlling these mitotic events would be through protein phosphorylation and dephosphorylation. In several systems, increased levels of protein phosphorylation are cell-cycle dependent phenomena. During meiotic maturation of Xenopus laevis oocytes, the incorporation of 32p into protein is maximal prior to mitosis (1). Similarly, in HeLa cells, nuclear matrix proteins are phosphorylated to a maximal extent during the premitotic (G2) phase (2). More specifically, the three major protein components of the nuclear lamina, lamins A, B, and C, incorporate 32p maximally at the time of nuclear-envelope dissolution (3). The presence of other mitosis-specific proteins has been detected also by two-dimensional gel electrophoretic analysis of synchronized HeLa cell populations (4).Davis et al. (5) have reported on the properties of a monoclonal antibody that recognized a set of phosphorylated proteins abundant in mitotic cells. Using one of these monoclonal antibodies, MPM-2 (5), we report here the localization of immunoreactive material to the centrosome, the kinetochore, and the midbody of mitotic cells. These results support the concept that specific protein phosphorylation may coordinate the transition of cells from interphas...

The kinetochore is a specialized structure at the centromere of eukaryotic chromosomes that attaches chromosomes to the mitotic spindle. Recently, several lines of evidence have suggested that kinetochores may have more than a passive role in the movement of chromosomes during mitosis and meiosis. Kinetochores seem to attract and 'capture' microtubules that grow from the spindle poles and microtubules may lengthen or shorten by the addition or subtraction of tubulin subunits at their kinetochore-associated ends. An attractive hypothesis is that kinetochores function as 'self-contained engines running on a microtubule track'. Here, we show that kinetochores can be experimentally detached from chromosomes when caffeine is applied to Chinese hamster ovary cells that are arrested in the G1/S phase of the cell cycle. The detached kinetochore fragments can still interact with spindle microtubules and complete all the mitotic movements in the absence of other chromosomal components. As these cells enter mitosis before DNA synthesis is completed, chromosome replication need not be a prerequisite for the pairing, alignment and segregation of kinetochores.

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The virtual fields method is an approach to inversely identify material parameters using full-field deformation data. In this manuscript, a new set of automaticallydefined virtual fields for non-linear constitutive models has been proposed. These new sensitivity-based virtual fields reduce the influence of noise on the parameter identification. The sensitivity-based virtual fields were applied to a numerical example involving small strain plasticity; however, the general formulation derived for these virtual fields is applicable to any non-linear constitutive model. To quantify the improvement offered by these new virtual fields, they were compared with stiffness-based and manually defined virtual fields. The proposed sensitivity-based virtual fields were consistently able to identify plastic model parameters and outperform the stiffness-based and manually defined virtual fields when the data was corrupted by noise.Keywords Virtual fields method · Sensitivity-based virtual fields · Inverse identification · Full field measurement · Elasto-plastic · Digital image correlation Electronic supplementary material The online version of this article

A summary of the properties of CGP 51901 is shown in Table 3. On the basis of its binding to IgE and IgE-secreting cells and its activity in vitro and in vivo, CGP 51901 is expected to be able to decrease serum IgE by direct clearance of IgE and by reduction of the numbers and productivity of IgE-secreting cells. The end result of reduction of IgE in the circulation and on mast cells is expected to be the attenuation of IgE-mediated reactions and the improvement in allergy symptoms. The effective serum concentration of CGP 51901 is expected to be in the range 1-10 micrograms/ml. Because CGP 51901 is an antibody specific for IgE, it is expected to be highly selective in its activity. Because IgE does not appear to be essential and because CGP 51901 has been rigorously tested to confirm its non-anaphylactic nature, this treatment is not expected to have any adverse effects. Therefore, CGP 51901 is expected to be safe and to have a good probability of being effective when it is tested in human clinical trials.

The virtual fields method is an approach to inversely identify material parameters using full-field deformation data. In this work, we extend the sensitivity-based virtual fields to large deformation anisotropic plasticity. The method is firstly generalized to the finite deformation framework and then tested on numerical data obtained from a finite element model of a deep-notched specimen subjected to a tensile loading. We demonstrated the feasibility of the method for two anisotropic plasticity models: Hill48 and Yld2000-2D, and showed that all the parameters could be characterise from such a test. The sensitivity-based virtual fields performed better than the currently accepted standard approach of user-defined ones in terms of accuracy and robustness. The main advantage of the sensitivity-based virtual fields comes from the automation of virtual fields generation. The process can be applied to any geometry and any constitutive law. Keywords The virtual fields method • Anisotropic plasticity • Sensitivity-based virtual fields • Material testing • Full-field measurements