Cell culture

About: Cell culture is a research topic. Over the lifetime, 133361 publications have been published within this topic receiving 5364150 citations. The topic is also known as: cell culture techniques.

Replicative senescence: implications for in vivo aging and tumor suppression.

Abstract: Normal cells have limited proliferative potential in culture, a fact that has been the basis of their use as a model for replicative senescence for many years. Recent molecular analyses have identified numerous changes in gene expression that occur as cells become senescent, and the results indicate that multiple levels of control contribute to the irreversible growth arrest. These include repression of growth stimulatory genes, overexpression of growth inhibitory genes, and interference with downstream pathways. Studies with cell types other than fibroblasts will better define the role of cell senescence in the aging process and in tumorigenesis.

Expression of hypoxia-inducible factor-1alpha and -2alpha in hypoxic and ischemic rat kidneys.

Abstract: Oxygen tensions in the kidney are heterogeneous, and their changes presumably play an important role in renal physiologic and pathophysiologic processes A family of hypoxia-inducible transcription factors (HIF) have been identified as mediators of transcriptional responses to hypoxia, which include the regulation of erythropoietin, metabolic adaptation, vascular tone, and neoangiogenesis In vitro, the oxygen-regulated subunits HIF-1alpha and -2alpha are expressed in inverse relationship to oxygen tensions in every cell line investigated to date The characteristics and functional significance of the HIF response in vivo are largely unknown High-amplification immunohistochemical analyses were used to study the expression of HIF-1alpha and -2alpha in kidneys of rats exposed to systemic hypoxia bleeding anemia, functional anemia (01% carbon monoxide), renal ischemia, or cobaltous chloride (which is known to mimic hypoxia) These treatments led to marked nuclear accumulation of HIF-1alpha and -2alpha in different renal cell populations HIF-1alpha was mainly induced in tubular cells, including proximal segments with exposure to anemia/carbon monoxide, in distal segments with cobaltous chloride treatment, and in connecting tubules and collecting ducts with all stimuli Staining for HIF-1alpha colocalized with inducible expression of the target genes heme oxygenase-1 and glucose transporter-1 HIF-2alpha was not expressed in tubular cells but was expressed in endothelial cells of a small subset of glomeruli and in peritubular endothelial cells and fibroblasts The kidney demonstrates a marked potential for upregulation of HIF, but accumulation of HIF-1alpha and HIF-2alpha is selective with respect to cell type, kidney zone, and experimental conditions, with the expression patterns partly matching known oxygen profiles The expression of HIF-2alpha in peritubular fibroblasts suggests a role in erythropoietin regulation

The origin and characteristics of a pig kidney cell strain, LLC-PK.

Abstract: A stable epithelial-like pig kidney cell strain has been established. This strain has been carried through more than 300 serial passages, has remained free of microbial and viral contaminants, and has retained a near diploid number of chromosomes. Attempts to produce tumors with these cells in immunosuppressed laboratory animals have been uniformly negative. The cells have grown rapidly in monolayer cultures with a split ratio of 1 to 15 at weekly intervals, but have failed to proliferate in suspension cultures. A subline adapted to growth on serum-free medium 199 has been carried through 145 passages on this medium. Several unusual morphologic features have been observed in these cultures including three-dimensional “domelike” structures. These cells have been found susceptible to some viruses and have been especially useful for viruses of domestic animals. LLC-PK1 cells have produced significant levels of plasminogen activator.

Tandem-duplicated Flt3 constitutively activates STAT5 and MAP kinase and introduces autonomous cell growth in IL-3-dependent cell lines.

Abstract: We have recently identified an internal tandem duplication of the human Flt3 gene in approximately 20% of acute myeloid leukemia (AML) cases. In the present study, the wild-type and the mutant Flt3 genes were transfected into two IL-3-dependent cell lines, 32D and BA/F3 cells. Mutant Flt3-transfected cells exhibited autonomous growth while wild-type Flt3-transfected cells with the continuous stimulation of Flt3 ligand exhibited a minimal proliferation. Cells expressing mutant Flt3 showed constitutive activation of STAT5 and MAP kinase. In contrast, Flt3 ligand stimulation caused rapid activation of MAP kinase but not STAT5 in cells expressing wild-type Flt3. Finally, we found constitutive activation of MAP kinase and STAT5 in all clinical samples of AML patients with mutant Flt3. Our study shows the significance of internal tandem duplication of Flt3 receptors for leukemia cell expansion.