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Genetics and exercise: an introduction
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Claude Bouchard, Henning Wackerhage
It is important to understand the distinction between germ cells and somatic cells. Male and female germ cells, sperm and oocyte, respectively, are termed gametes. A mature germ cell has only 22 autosomes plus one sex chromosome (i.e. 23 chromosomes in total) in its nucleus instead of the full complement of 46 chromosomes seen in somatic cells (i.e. body cells or non-germ cells). A germ cell containing 23 chromosomes is said to be “haploid”, whereas normal somatic cells contain a “diploid” set of chromosomes. When a haploid sperm and a haploid oocyte fuse, they form a diploid, fertilized oocyte, termed zygote, which is the first cell of the new organism. It has 2 × 22 autosomes plus either two X chromosomes (XX, a female) or an X and a Y (XY, a male) chromosome.
Basic genetics and patterns of inheritance
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Gene therapy involves insertion of normal copies of genes into individuals who have genetic diseases. This can potentially be accomplished by either somatic cell or germ cell gene therapy. Most work thus far has focused on somatic cell gene therapy. There are two ways to approach somatic cell gene therapy. Ex vivo gene therapy involves removing a patient’s cells from the body, inserting the normal gene copy into the cells, and then returning the cells to the body. In in vivo gene therapy, cells are treated while inside the patient’s body. For successful gene therapy, the cell requiring treatment must be easily accessible and relatively long-lived. Some of the earliest human gene therapy trials were performed for severe combined immune deficiency due to adenosine deaminase deficiency, using bone marrow stem cells. Other cells under consideration for therapy have included lymphocytes, hepatocytes, muscle cells, and respiratory epithelial cells. More recently, gene therapy for Leber’s congenital amaurosis has been accomplished by replacement of the defective gene locally to the retina of the eye. Types of genetic diseases that are amenable to somatic cell gene therapy are primarily autosomal recessive or X-linked disorders that result in almost total lack of normal protein. Reconstitution of even 5% to 10% of normal protein levels appears to be sufficient to treat these diseases. Dominant disorders that are caused by heterozygosity for mutant and normal genes (dominant-negative mutations) are not likely to be treatable by gene replacement; methods to block production of the mutant protein will be required.
The cell and tissues
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Cells, like the organism they form, are mortal, but they are able to postpone their death by asexual reproduction or, in other words, by simply dividing in two. They can do this only a certain number of times before they lose this ability and die. This process of somatic cell division is called mitosis. Mitosis, or the mitotic phase, takes up only a small part of the overall life of a cell. Only a proportion of cells are dividing at any time, so most of the cells are not involved in producing new cells but are involved in the normal day-to-day cellular function. This non-dividing phase is called interphase. During interphase, the cells also grow and replicate (double by making exact copies) their DNA and organelles ready for the next mitotic phase. It is during interphase that the DNA in the nucleus does a self-examination and carries out repairs that help reduce the number of mutations in individual genes. The combination of interphase and the mitotic phase is known as the cell cycle (see Figure 3.9) (Marieb and Hoehn 2019).
3D bioprinting for organ and organoid models and disease modeling
Published in Expert Opinion on Drug Discovery, 2023
Amanda C. Juraski, Sonali Sharma, Sydney Sparanese, Victor A. da Silva, Julie Wong, Zachary Laksman, Ryan Flannigan, Leili Rohani, Stephanie M. Willerth
There exists a need for an in vitro biomimetic testicular model to evaluate human testicular function, and to perform medication, drug and toxicology screens. The spermatogenic niche consists of somatic cells and supports spermatogenesis and testosterone production. These somatic cells consist of Sertoli cells, myoid cells, Leydig cells, endothelial cells, and macrophages. These cells help coordinate a complex, highly regulated sequence of processes to support the differentiation of spermatogonial stem cells (SSC) to haploid spermatids, referred to as spermatogenesis; as well as the morphologic maturation of round spermatids to elongated spermatozoa, termed spermiogenesis. The somatic cells of the testicular microenvironment govern the temporal and spatial regulation of these events through direct contact, juxtracrine and paracrine signaling.
Stem cell therapy for salivary gland regeneration after radiation injury
Published in Expert Opinion on Biological Therapy, 2023
Akshaya Upadhyay, Simon D Tran
Reprogramming of somatic cells became a reality with induced pluripotent stem cells (established by introducing four factors: Sox2, Oct3/4, c-Myc, and Klf4 in somatic cells). This has inspired researchers to enhance and modify somatic cells for therapeutics. Sumita et al. recently initiated a clinical trial to treat radiation-induced xerostomia using effective-mononuclear cells (E-MNCs) by amplifying peripheral blood mononuclear cells’ anti-inflammatory and vasculogenic properties by expanding these cells in vitro with specific growth factors [26]. Another work with somatic cells worth mentioning here is using mouse embryonic fibroblasts for forming SG organoids. First, the epithelial transition of the fibroblasts was carried out, followed by SG-specific epithelial initiation, which resulted in the successful formation of SG-like organoids [5].
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.