Foreskin Fibroblasts (foreskin + fibroblast)

Distribution by Scientific Domains

Kinds of Foreskin Fibroblasts

  • human foreskin fibroblast


  • Selected Abstracts


    Stable maintenance of 5, -reductase activity in long-term subcultures of fibroblasts derived from the foreskin

    INTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2002
    Kazumi Nakae
    Abstract Background: There is up to a 50-fold variation in control subjects in current assays of 5,-reductase activity which makes interpretation difficult. It was therefore attempted in this study to establish an assay method which produced stable 5,-reductase activity in long-term subcultured foreskin fibroblasts. Methods: Foreskin fibroblasts were obtained from three boys with phimosis (control subjects), three patients with Reifenstein syndrome and one patient with 5,-reductase deficiency (due to mutation L113P in exon 2 of the SRD5A2 gene). To maximize the number of cells in the DNA synthesis phase, cells were subcultured consistently to approximately 70% confluency. Thawed cells, frozen after the third subculture, were incubated for 24 h with [1,,2,- 3H] testosterone. 5,-Reductase activity was expressed as the sum of formed [3H] 5,-reduced metabolites (separated by thin-layer chromatography). Results: The full range of 5,-reductase activity in controls and patients with Reifenstein syndrome was 3.44,15.59 pmol/h per mg protein: a 4.53-fold variation. The activity in the patient with 5,- reductase deficiency was 0.52 pmol/h per mg protein. Conclusion: By the cell culture methods used in this study, which aimed to increase the number of cells in the DNA synthesis phase, foreskin fibroblasts maintained a considerably stable level of 5,-reductase activity during long-term subculture. Therefore, this assay method can be used for differential diagnosis of 5,-reductase deficiency from other relevant entities. [source]


    Properties of murine embryonic stem cells maintained on human foreskin fibroblasts without LIF,

    MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2008
    G.L. Meng
    Abstract In embryonic stem (ES) cells, leukemia inhibitory factor (LIF)/STAT3, wnt and nodal/activin signaling are mainly active to control pluripotency during expansion. To maintain pluripotency, ES cells are typically cultured on feeder cells of varying origins. Murine ES cells are commonly cultured on murine embryonic fibroblasts (MEFs), which senesce early and must be frequently prepared. This process is laborious and leads to batch variation presenting a challenge for high-throughput ES cell expansion. Although some cell lines can be sustained by exogenous LIF, this method is costly. We present here a novel and inexpensive culture method for expanding murine ES cells on human foreskin fibroblast (HFF) feeders. After 20 passages on HFFs without LIF, ES cell lines showed normal expression levels of pluripotency markers, maintained a normal karyotype and retained the ability to contribute to the germline. As HFFs do not senesce for at least 62 passages, they present a vast supply of feeders. Mol. Reprod. Dev. 75: 614,622, 2008. 2007 Wiley-Liss, Inc. [source]


    Cyclin-dependent kinase 1 plays a critical role in DNA replication control during rat liver regeneration,

    HEPATOLOGY, Issue 6 2009
    Delphine Garnier
    Liver regeneration is a unique process to restore hepatic homeostasis through rapid and synchronous proliferation of differentiated hepatocytes. Previous studies have shown that hepatocyte proliferation is characterized by high expression levels of the "mitotic" cyclin-dependent kinase 1 (Cdk1) during S-phase compared to other mammalian cells. In the light of findings showing that Cdk1 compensates for the loss of Cdk2 and drives S-phase in Cdk2-deficient cells derived from Cdk2 knockout mice, we took advantage of the models of liver regeneration following partial hepatectomy and primary cultures of normal rat hepatocytes to further examine the involvement of Cdk1 during DNA replication in hepatocytes and to dissect specific cell cycle regulation in hepatocytes compared to control human foreskin fibroblasts. In hepatocytes, Cdk1 exhibited a biphasic activation pattern correlating S-phase and G2/M transition, bound to cyclin A or B1 and localized to the nucleus during DNA replication. Importantly, small interfering RNA (siRNA)-mediated silencing of Cdk1 led to a strong decrease in DNA synthesis without affecting centrosome duplication. Furthermore, in hepatocytes arrested by the iron chelator O-Trensox in early S-phase prior to DNA replication, Cdk1/cyclin complexes were active, while replication initiation components such as the minichromosome maintenance 7 (Mcm7) protein were loaded onto DNA. Moreover, Mcm7 expression and loading onto DNA were not modified by Cdk1 silencing. Conversely, in fibroblasts, Cdk1 expression and activation were low in S-phase and its silencing did not reduce DNA synthesis. Conclusion: Cdk1 is essential for DNA replication downstream formation of replication initiation complexes in hepatocytes but not in fibroblasts and, as such, our data exemplify crucial differences in the cell cycle regulation between various mammalian cell types. (HEPATOLOGY 2009.) [source]


    Stable maintenance of 5, -reductase activity in long-term subcultures of fibroblasts derived from the foreskin

    INTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2002
    Kazumi Nakae
    Abstract Background: There is up to a 50-fold variation in control subjects in current assays of 5,-reductase activity which makes interpretation difficult. It was therefore attempted in this study to establish an assay method which produced stable 5,-reductase activity in long-term subcultured foreskin fibroblasts. Methods: Foreskin fibroblasts were obtained from three boys with phimosis (control subjects), three patients with Reifenstein syndrome and one patient with 5,-reductase deficiency (due to mutation L113P in exon 2 of the SRD5A2 gene). To maximize the number of cells in the DNA synthesis phase, cells were subcultured consistently to approximately 70% confluency. Thawed cells, frozen after the third subculture, were incubated for 24 h with [1,,2,- 3H] testosterone. 5,-Reductase activity was expressed as the sum of formed [3H] 5,-reduced metabolites (separated by thin-layer chromatography). Results: The full range of 5,-reductase activity in controls and patients with Reifenstein syndrome was 3.44,15.59 pmol/h per mg protein: a 4.53-fold variation. The activity in the patient with 5,- reductase deficiency was 0.52 pmol/h per mg protein. Conclusion: By the cell culture methods used in this study, which aimed to increase the number of cells in the DNA synthesis phase, foreskin fibroblasts maintained a considerably stable level of 5,-reductase activity during long-term subculture. Therefore, this assay method can be used for differential diagnosis of 5,-reductase deficiency from other relevant entities. [source]


    bcl-2-specific siRNAs restore Gemcitabine sensitivity in human pancreatic cancer cells

    JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 2 2007
    Kinya Okamoto
    Abstract Gemcitabine has been shown to ameliorate disease related symptoms and to prolong overall survival in pancreatic cancer.Yet, resistance to Gemcitabine is commonly observed in this tumour entity and has been linked to increased expression of anti-apoptotic bcl-2. We therefore investigated if and to what extend silencing of bcl-2 by specific siRNAs (siBCL2) might enhance Gemcitabine effects in human pancreatic carcinoma cells. siBCL2 was transfected into the pancreatic cancer cell line YAP C alone and 72 hrs before co-incubation with different concentrations of Gemcitabine. Total protein and RNA were extracted for Western-blot analysis and quantitative polymerase chain reaction. Pancreatic cancer xenografts in male nude mice were treated intraperitoneally with siBCL2 alone, Gemcitabine and control siRNA or Gemcitabine and siBCL2 for 21 days. Combination of both methods lead to a synergistic induction of apoptosis at otherwise ineffective concentrations of Gemcitabine. Tumour growth suppression was also potentiated by the combined treatment with siBCL2 and Gemcitabine in vivo and lead to increased TUNEL positivity. In contrast, non-transformed human foreskin fibroblasts showed only minor responses to this treatment. Our results demonstrate that siRNA-mediated silencing of anti-apoptotic bcl-2 enhances chemotherapy sensitivity in human pancreatic cancer cells in vitro and might lead to improved therapy responses in advanced stages of this disease. [source]


    Properties of murine embryonic stem cells maintained on human foreskin fibroblasts without LIF,

    MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2008
    G.L. Meng
    Abstract In embryonic stem (ES) cells, leukemia inhibitory factor (LIF)/STAT3, wnt and nodal/activin signaling are mainly active to control pluripotency during expansion. To maintain pluripotency, ES cells are typically cultured on feeder cells of varying origins. Murine ES cells are commonly cultured on murine embryonic fibroblasts (MEFs), which senesce early and must be frequently prepared. This process is laborious and leads to batch variation presenting a challenge for high-throughput ES cell expansion. Although some cell lines can be sustained by exogenous LIF, this method is costly. We present here a novel and inexpensive culture method for expanding murine ES cells on human foreskin fibroblast (HFF) feeders. After 20 passages on HFFs without LIF, ES cell lines showed normal expression levels of pluripotency markers, maintained a normal karyotype and retained the ability to contribute to the germline. As HFFs do not senesce for at least 62 passages, they present a vast supply of feeders. Mol. Reprod. Dev. 75: 614,622, 2008. 2007 Wiley-Liss, Inc. [source]


    Design and characterization of a modified T-flask bioreactor for continuous monitoring of engineered tissue stiffness

    BIOTECHNOLOGY PROGRESS, Issue 3 2010
    Richard A. Lasher
    Abstract Controlling environmental conditions, such as mechanical stimuli, is critical for directing cells into functional tissue. This study reports on the development of a bioreactor capable of controlling the mechanical environment and continuously measuring force-displacement in engineered tissue. The bioreactor was built from off the shelf components, modified off the shelf components, and easily reproducible custom built parts to facilitate ease of setup, reproducibility and experimental flexibility. A T-flask was modified to allow for four tissue samples, mechanical actuation via a LabView controlled stepper motor and transduction of force from inside the T-flask to an external sensor. In vitro bench top testing with instrumentation springs and tissue culture experiments were performed to validate system performance. Force sensors were highly linear (R2 > 0.998) and able to maintain force readings for extended periods of time. Tissue culture experiments involved cyclic loading of polyurethane scaffolds seeded with and without (control) human foreskin fibroblasts for 8 h/day for 14 days. After supplementation with TGF-,, tissue constructs showed an increase in stiffness between consecutive days and from the acellular controls. These experiments confirmed the ability of the bioreactor to distinguish experimental groups and monitor tissue stiffness during tissue development. 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]


    Infection with Toxoplasma gondii results in dysregulation of the host cell cycle

    CELLULAR MICROBIOLOGY, Issue 5 2008
    Robert E. Molestina
    Summary Mammalian cells infected with Toxoplasma gondii are characterized by a profound reprogramming of gene expression. We examined whether such transcriptional responses were linked to changes in the cell cycle of the host. Human foreskin fibroblasts (HFFs) in the G0/G1 phase of the cell cycle were infected with T. gondii and FACS analysis of DNA content was performed. Cell cycle profiles revealed a promotion into the S phase followed by an arrest towards the G2/M boundary with infection. This response was markedly different from that of growth factor stimulation which caused cell cycle entry and completion. Transcriptional profiles of T. gondii -infected HFF showed sustained increases in transcripts associated with a G1/S transition and DNA synthesis coupled to an abrogation of cell cycle regulators critical in G2/M transition relative to growth factor stimulation. These divergent responses correlated with a distinct temporal modulation of the critical cell cycle regulator kinase ERK by infection. While the kinetics of ERK phosphorylation by EGF showed rapid and sustained activation, infected cells displayed an oscillatory pattern of activation. Our results suggest that T. gondii infection induces and maintains a ,proliferation response' in the infected cell which may fulfill critical growth requirements of the parasite during intracellular residence. [source]