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Point cloud characterization
Published in Rodrigo Rojas Moraleda, Nektarios A. Valous, Wei Xiong, Niels Halama, Computational Topology for Biomedical Image and Data Analysis, 2019
Rodrigo Rojas Moraleda, Nektarios A. Valous, Wei Xiong, Niels Halama
A point cloud is obtained from localization images; this is achieved using the approach of ref. [55]. More specifically, localization images are segmented based on a density threshold procedure to exclude regions outside the nuclear membrane as well as chromatin-depleted regions inside the nucleus (e.g., nucleoli). Fig. 5.1 shows an example of a localization image of histone H2A in the nucleus of a HeLa cell labeled with a yellow fluorescent protein. The localized fluorophores are blurred with a Gaussian function corresponding to their localization accuracy. The wide-field image of Fig. 5.1i is presented in Fig. 5.1ii. Localized histones after merging the acquired time series of SPDM images are shown in Fig. 5.1iii; each localized fluorophore is represented by a white point. Fig. 5.1iv presents a histone point cloud obtained by thresholding the KDE.
Imaging of Intracellular Targets
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
An example of intranuclear imaging is presented by Cornelissen et al. (2011) who imaged DNA damage in vivo using immunoconjugates. Signal amplification was achieved by focusing on the phosphorylated histone H2A-variant H2AX, γH2AX, an early and almost universal feature of the eukaryotic response to DNA double strand breaks. Hundreds of copies of γH2AX accumulate in foci at DNA double strand breaks. The estimated number of γH2AX formed following doses of 2–10 Gy irradiation would be 2.4 × 105 to 1.2 × 106 which is comparable to the number of targets needed for extracellular molecular imaging. They attached the TAT-peptide covalently to a fluorophore- or 111In-labeled anti-γH2AX antibody to reach the nucleoplasm. Tat/IgG conjugation ratio was 5:1 as determined by radioiodination of the TAT-peptide. As already mentioned, TAT is not only able to route the antibody to the cytoplasm but it also contains a NLS sequence to import its cargo to the nucleus where it is able to specifically bind to its target and image DNA double strand breaks.
Use of Recombinant DNA Technology for Engineering Mammalian Cells to Produce Proteins
Published in Anthony S. Lubiniecki, Large-Scale Mammalian Cell Culture Technology, 2018
The possibility that an upstream promoter may occlude transcription from a downstream promoter (147) suggests that insertion of a transcription termination signal upstream from the second transcription unit in an expression vector may potentiate expression from that promoter by preventing transcription from extending through the upstream sequences. Indeed, this has been directly demonstrated by the insertion of a histone H2A gene termination region or a mouse beta-globin gene termination region between two tandem alpha-globin transcription units to elicit an approximately sevenfold increase in expression from the downstream transcription unit (148). Transcription termination signals would also provide an approach to minimize transcription from the opposite strand of DNA which can suppress gene expression through the formation of antisense mRNA (149, 150).
The emergence of nanoporous materials in lung cancer therapy
Published in Science and Technology of Advanced Materials, 2022
Deepika Radhakrishnan, Shan Mohanan, Goeun Choi, Jin-Ho Choy, Steffi Tiburcius, Hoang Trung Trinh, Shankar Bolan, Nikki Verrills, Pradeep Tanwar, Ajay Karakoti, Ajayan Vinu
Bortezomib (BTZ) is a clinically approved proteasome inhibitor for different cancer treatments. The main drawback of this medication is the reduced solubility similar to cisplatin. BTZ loaded MSNs modified and hybridized with histone H2A peptide showed better drug delivery in lung cancer cells. Histone H2A is a chimeric peptide that can overcome targeting obstacles in drug delivery. On comparing these two studies, the MSN modified with targeting agent is more specific with better efficacy [197]. Similarly, van Rijt et al. reported the MSNs capped with avidin (a tetrameric biotin binding protein) and functionalised with matrix metalloproteinase inhibitor 9 (MMP9) linkers. The linkers are peptide sequences which can be cleaved by overexpressed MMP9 in the cancer cells. The drugs, BTZ and cisplatin were loaded separately, and the efficiency of MSN as a delivery agent was compared. It was found that in lung cancer cell line A549 and H1299, both the drugs were released only in MMP9 expressed cell lines [198].
Autoantibodies and cancer among asbestos-exposed cohorts in Western Australia
Published in Journal of Toxicology and Environmental Health, Part A, 2021
Renee N Carey, Jean C Pfau, Marvin J Fritzler, Jenette Creaney, Nicholas de Klerk, Arthur W (Bill) Musk, Peter Franklin, Nita Sodhi-Berry, Fraser Brims, Alison Reid
Immunoassays were performed by the Mitogen Diagnostics Laboratory (Calgary, Alberta, Canada). The levels of antibodies against 13 nuclear antigens were evaluated: dsDNA, Sm, histone (H2A, H2B, H3, H4), Jo-1 (histidyl tRNA synthetase), ribonucleoprotein (RNP), ribosomal P protein, proliferating cell nuclear antigen (PCNA), SSA/Ro60, SSB/La, Ro52/TRIM21, PM-Scl, Scl-70 (topoisomerase 1), centromere B (CENP-B). This multiplexed extractable nuclear antibody (ENA) profile utilized an addressable laser bead immunoassay (ALBIA) provided by TheraDiag (FIDIS: Paris, France). Cutoffs were established using internal calibrators provided by the manufacturers and control sera included with each assay run. Results were expressed as chemiluminescence intensity units (CIU) for ALBIA.