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Manipulating the Intracellular Trafficking of Nucleic Acids
Published in Kenneth L. Brigham, Gene Therapy for Diseases of the Lung, 2020
Kathleen E. B Meyer, Lisa S. Uyechi, Francis C. Szoka
The nucleus is bounded by the nuclear envelope, which encloses chromatin and the machinery necessary for gene transcription. The nucleus is a dynamic structure, which disassembles at the onset of mitosis and reassembles during telophase. The envelope consists of two membrane bilayers, posing a considerable hydrophobic barrier to macromolecular transport (Fig. 3). The outer nuclear membrane is continuous with the endoplasmic reticulum, and with the inner nuclear membrane forms a perinuclear space that is continuous with the endoplasmic reticulum lumen (82,83). The inner nuclear membrane is supported internally by the nuclear lamina, a network of lamin proteins that lines the inner side of the envelope (82). The lamina also is thought to provide attachment sites for chromatin (84-86). The very interior of the nucleus is a network of DNA, RNA, and proteins. It is the active transcriptions sites that are the targets of gene delivery.
Hot topics in medicine
Published in Viyaasan Mahalingasivam, Marc A Gladman, Manoj Ramachandran, Secrets of Success: Getting into Medical School, 2020
Veena Naganathar, Asil Tahir, Pairaw Kader, Omar Chehab
We are continually losing cells and replacing them with new ones that carry out the same function. This process of new cell growth (mitosis) is tightly regulated by various cellular mechanisms to ensure that we have the right number of cells and that the new cells carry out their intended function. Cancer is the breakdown of this regulation process where the new cells are dissenters, rendering them harmful tissues to our body. Alarmingly, these cells have the capability to spread, either by damaging normal cells in their vicinity (invasion) or by entering our blood and lymphatic systems to cause damage in a more distant location in the body (metastasis).
Basic Cell Biology
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
In mitosis, each chromosome duplicates itself. The duplicated strands separate as the nucleus divides, so that the daughter nuclei have the same set of chromosomes as their parent cell. Figure 2.2 shows a diagrammatic representation of the process of mitosis in a cell. During mitosis, a cell passes through four stages: prophase, metaphase, anaphase, and telophase. During prophase, each chromosome doubles itself, and the nuclear membrane and nucleus disappear. During metaphase, spindles form and chromosomes lie on the equatorial plate. During anaphase, chromosomes separate, and each half moves toward a pole. During telophase, the nucleus appears, and the cell divides into two daughter cells — each having an identical set of diploid chromosomes. The process of mitosis is so precise that any change in the chromosomes or DNA would definitely reflect in daughter cells after completion of cell division.
Cationic nanocapsule suspension as an alternative to the sublingual delivery of nifedipine
Published in Pharmaceutical Development and Technology, 2023
Bárbara Felin Osmari, Giovana Aime Medeiros, Jéssica Brandão Reolon, Vinícius Costa Prado, Natália Brucker, Letícia Cruz
Genotoxic substances can break genetic material, causing abnormal changes in genes or chromosomes structure (Islam et al. 2017). The genotoxicity was evaluated by observing chromosomal aberrations (CA%) (Table 3). The evaluations confirmed the genotoxicity of glyphosate (positive control) that presented CA of 1.07 ± 0.17%. On the other hand, the negative control group treated with water presented CA of 0.24 ± 0.06%, being similar to NC-NIFE (0.14 ± 0.10%), NC (0.19 ± 0.09%), and vehicle (0.16 ± 0.14%) (p > 0.05). Interestingly, NIFE showed the lowest CA (0.07 ± 0.10%). In Figure 3(B), the images of CA observed in this study are shown. The different mitosis phases are shown in Figure 3(A). Thus, NC-NIFE demonstrated the absence of chromosomic aberrations, which was also observed in other nanoencapsulated drugs (Marchiori et al. 2010; Leng et al. 2018).
The Role of Insulin-like Growth Factor-Axis and Mitotic Index in South Indian Neonates with Small for Gestational Age
Published in Fetal and Pediatric Pathology, 2023
Nithya M. N., Krishnappa J., Sheela S. R., Venkateswarlu Raavi
Mitosis is an intrinsic property of a cell that contributes to the growth of the somatic cells. The mitotic index is the percentage of cells undergoing mitosis in a given cell population and it is a measure of cellular proliferation [16]. In our previous study, we observed that the mitotic index of lymphocytes from different blood groups (A, B, AB, and O) exposed to ionizing radiation showed a significant difference indicating a differential proliferation response among the blood types [16]. The mitosis in fetal cells contributes to the growth and development of the fetus and it depends on nutritional status, hormones, growth factors, and environmental factors. The studies on GH/IGF-axis components and SGA revealed that there are contrasting results that might depend on nutrition, environment, hormone levels, genetic makeup [2, 17]. Delineating the role of the IGF-axis and mitotic index in SGA may help improve management of SGA neonates. In the present study, we measured the levels of IGF1, IGF2, and IGFBP3 proteins, mitotic index in the cord blood, and the expression of IGFR1 and IGFR2 mRNA in the placenta to find if there any difference in these parameters between AGA and SGA neonates born to south Indian women.
Radiosensitivity of seedling traits to varying gamma doses, optimum dose determination and variation in determined doses due to different time of sowings after irradiation and methods of irradiation in faba bean genotypes
Published in International Journal of Radiation Biology, 2023
Rajdeep Guha Mallick, Subhradeep Pramanik, Manas Kumar Pandit, Akhilesh Kumar Gupta, Subhrajit Roy, Sanjay Jambhulkar, Ashutosh Sarker, Rajib Nath, Somnath Bhattacharyya
Siahpoosh et al. (2020) observed an increased amount of mitotic and meiotic anomalies with increasing doses of gamma radiation in mutant plants of Vicia faba cv. Saraziri. The increased amount of mutations with the increasing doses of ionizing radiation interferes with the cell division process viz., mitosis and meiosis. Mitotic anomalies result in impaired cell divisions thus halting the cell cycle at checkpoints resulting in growth retardation of meristematic cells. Differential mutation loads in plant propagules exposed to varying doses of ionizing radiation results in deviation in the growth and development of plants in comparison to the un-irradiated propagules. Meristematic cell deaths are often encountered as plants avoid the transmission of lethal mutations in advanced generations (Raina et al. 2021).