MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedonyuk 2010

BIOLOGY

SECTION 1. BIOLOGICAL FOUNDATIONS OF HUMAN VITAL ACTIVITY

1.3. MOLECULAR-GENETIC AND CELLULAR LEVELS OF ORGANIZATION OF LIFE

1.3.4. Temporal Organization of Cells

Ex Vivo Cell Life, Cell Cloning, and Significance of the Cell Culture Method

A population of Cells grown under controlled conditions in a nutrient medium outside the Organism (in vitro) is called a cell culture. A population of genetically identical cells derived from a single common ancestor cell through successive mitotic divisions is called a cell clone, and The process of clone generation is known as cloning. Primary and continuous (established) cell cultures are distinguished.

Primary cultures. Cells can be isolated from various human Tissues and Organs (such as Skin, Bone Marrow, Blood, and embryonic tissues). Connective Tissue cells (fibroblasts) and peripheral Blood Leukocytes are most commonly used. Cultured cells proliferate rapidly via division; however, their division capacity is limited. For embryonic fibroblasts, this limit is approximately 50 divisions, after which the culture senesces and dies. Cells obtained from adult tissues are capable of significantly fewer divisions. Many scientists attribute this phenomenon—known as the Hayflick limit in honor of its discoverer—to cellular Aging.

Continuous (established) cultures consist of malignant tumor cells capable of unlimited divisions, allowing them to be maintained in vitro for years. Since 1951, the HeLa cell line—derived from a Cervical Cancer tissue—has been cultivated in numerous laboratories worldwide. The strain is named after the initials of the patient from whom the tumor sample was taken.

Cell cultures are widely applied in the Diagnosis of viral infections, human karyotyping, prenatal and postnatal diagnosis of chromosomal Genetic Disorders, investigation of cellular aging mechanisms, assessment of chemical mutagenicity, and The production of Pharmaceuticals. This method enables the propagation of Influenza, poliomyelitis, and tick-borne encephalitis Viruses for vaccine production. Plant cell cultures are also utilized to yield medicinal substances from plants that are difficult to cultivate on plantations (such as ginseng). Furthermore, cell cultures form the foundation of somatic cell Hybridization techniques used in chromosome mapping.