Cell’s development is divided two phase: growth and differentiation to mature cell with different biological functions and then death. There is a balance between growth and death to maintain the endothelial balance. The disorder of this balance can cause the malignant diseases. The immortality is the most important property of malignant cells, not for normal cells. The tumor suppressive genes include gene P53; gene P21 cip1 gene P 300/CBP, gene BTG 2 and gene P73. Genes play role of repaire of damaged DNA include RM, RPA, BRCA1 and BRCA2. The lost telomerase or inhibition of telomerase will exclude the tumor cells.
neoplasms ; Cell Growth Processes

STUDY DESIGN: An in vitro experiment. OBJECTIVES: To evaluate the mRNA expressions of matrix components, and analyze the cellular proliferation and proteoglycan synthesis of human intervertebral disc cells in response to dexamethasone and TGF-beta1 SUMMARY OF LITERATURE REVIEW: Corticosteroids are responsible for the regulation of a diverse range of biological processes through modulation of the expression of target genes. The direct injection of methylprednisolone to the intervertebral disc (IVD) has been shown to cause degeneration and calcification of the disc in rabbits. Systemic administration of hydrocortisone induced degeneration of notochordal cells, which accelerated the aging process of the disc in mice. Transforming growth factor beta-1 (TGF-beta1) is known as a potent agent for the proliferation, differentiation and matrix synthesis of IVD. MATERIALS AND METHODS: IVD cells were isolated from ten patients, and subsequently cultured. Various doses of dexamethasone (DEX) and/or TGF-beta1 were administered to the IVD cultures. DNA and proteoglycan syntheses were measured by the incorporation of [3H]-thymidine and [35S]-sulfate, respectively. RT-PCRs were performed for the expressions of aggrecan, collagen types I and II, and osteocalcin mRNA. RESULTS: Cultures with DEX showed increased cellular proliferation and decreased proteoglycan synthesis (p<0.05). TGF-beta1 potentiated the proliferative effect of DEX, but failed to stimulate proteoglycan synthesis in the cultures containing DEX. There were no recognizable changes in the mRNA expressions of aggrecan, collagen types I and II, and osteocalcin in response to DEX and TGF-beta1. CONCLUSIONS: DEX demonstrated a proliferative effect on human IVD cells, with the combination of DEX and TGF-beta1 showing potentiation of the proliferative effect, while at high doses(100 and 1000nM, the DEX was shown to down-regulate the proteoglycan synthesis. Caution should be exercised in the use of corticosteroid in the therapeutic approaches for the treatment of disc disease or in the regenerative matrix of the IVD.
Adrenal Cortex Hormones ; Aggrecans ; Aging ; Animals ; Biological Processes ; Cell Proliferation ; Collagen ; Dexamethasone* ; DNA ; Humans* ; Hydrocortisone ; Intervertebral Disc* ; Methylprednisolone ; Mice ; Notochord ; Osteocalcin ; Proteoglycans ; Rabbits ; RNA, Messenger ; Transforming Growth Factor beta1 ; Transforming Growth Factors

Cell Growth Processes ; Hemangioma ; pathology ; physiopathology ; Histiocytoma, Benign Fibrous ; pathology ; physiopathology ; Humans ; Neoplasms ; physiopathology

The schemes of dose fractionation play an important role in tumor radiotherapy. We used mathematical methods to describe the process of tumor cells evolution during radiotherapy, trying to find how the schemes of dose fractionation affect tumor cells. In clinical radiobiology, linear-quadratic (LQ) model is frequently used to describe radiation effects of tumor cells. We integrated LQ model with effect of oxygen, and with the phenomenon of repopulation and reoxygenation in the theory of radiation biology. While we considered the disappearing progress of doomed cells in tumor, we established the mathematical model of tumor evolution in radiotherapy. We simulated some common treatment schedules, and studied the change role of tumor cells during radiotherapy. These results can serve for the optimization of dose fractionation scheme based on tumor radiobiological characteristics.
Cell Growth Processes ; radiation effects ; Dose Fractionation ; Humans ; Models, Theoretical ; Neoplasms ; pathology ; physiopathology ; radiotherapy ; Radiobiology

There has been no study aimed at directly determiningof the periods of Sertoli cell proliferation in birds evendomestic fowl. The aims of this study were to observe thecessation of post-hatching mitotic proliferation of Sertolicells in domestic fowl, and to determine the volumedensity of Sertoli and germ cells during this period. Atotal of 50 Leghorn chicks were used in this study. Thetestes sections of the animals were immunostained withBrdU to observe the proliferation of cells from one to 10weeks of age. The volume density of the Sertoli and germcells were determined using the standard point countingmethod. The volume density of the germ cell nuclei wasinitially less than that of the Sertoli cells but the volumedensity converged by week 6, and remained relativelyconstant until the commencement of meiosis. Clearlabeling of Sertoli and germ cells was observed from week1 to week 7. The only those cells still labeled after 8 weekswere germ cells, indicating that Sertoli cell proliferationhad ceased. Therefore, it is recommended that anyresearch into the testes of domestic fowl should considerthe cessation of Sertoli cell proliferation by approximately8 weeks.
Animals ; Bromodeoxyuridine/metabolism ; Cell Differentiation/physiology ; Cell Growth Processes/physiology ; Chickens/*physiology ; Histocytochemistry/veterinary ; Male ; Mitosis/physiology ; Sertoli Cells/*cytology/metabolism ; Spermatocytes/cytology ; Testis/*cytology/metabolism

OBJECTIVETo explore the effect of focal-adhesion micromanipulation on the biological behavior of fibroblast.

METHODSMicro-pot was made by microcontact printing. The molecules of constitutive protein was adhered on micro-pot by self-assemble of peptides. Skin fibroblasts were cultured on the membrane by self-made biomechanical cell culture for 2 weeks. Morphology observation and cell immunohistochemistry analysis was performed.

RESULTSAfter 2 weeks, the morphology of the fibroblasts was diverse and more compliant. Cell immunohistochemistry analysis found that the expression of integrinbeta1, alpha5 and tensin was dramatically reduced.

CONCLUSIONSThe morphology and the biological behaviour of the fibroblasts in hypertrophic scar can be changed after micromanipulation of focal adhesion.

Cell Culture Techniques ; Cell Growth Processes ; Cells, Cultured ; Cicatrix ; surgery ; Dermis ; cytology ; Female ; Fibroblasts ; cytology ; Focal Adhesions ; Humans ; Immunohistochemistry ; Male ; Wound Healing

OBJECTIVETo study the expression of RAS protein in human glioma tissues and its influence on tumor growth.

METHODSRAS protein expression in glioma tissues was determined by immunohistochemical (IHC) staining. Subsequently, MTT cell proliferation assay, flow cytometry and Western blotting were used to assay U251 cells with reduced RAS expression.

RESULTSThe expression of RAS in glioma was increased and strongly correlated with pathological grade. Downregulation of RAS resulted in glioma cells growth suppression and increased apoptosis.

CONCLUSIONThe expression level of RAS protein in human glioma was increased. Downregulation of RAS can inhibit glioblastoma cell growth through the RAS signal pathway.

Brain Neoplasms ; genetics ; metabolism ; pathology ; Cell Growth Processes ; genetics ; Cell Line, Tumor ; Down-Regulation ; Glioma ; genetics ; pathology ; Humans ; Immunohistochemistry ; ras Proteins ; biosynthesis ; genetics

Metabolic flux analysis is a very powerful tool to understand CO2 fixation and light energy utilization of microalgae during photoautotrophic cultivation. A comprehensive network structure for the autotrophic growth of Synechococcus sp. PCC7942 was proposed, and the carbon and energetic metabolism under different incident light intensity was investigated based on metabolic flux analysis in this paper. These results showed that CO2 fixation was the main energy and reducing potential trap which accounted for 85% and 70% of the total energy and reducing potential consumption respectively. We also found that the cell yield and the maximum cell yield based on ATP synthesis were maintained 2.80 g/mol and 2.97 g/mol respectively under the appointed incident intensity. But the cell yield on absorbed light energy their corresponding energy conversion efficiency were descended with the increasing of incident intensity.
Carbon ; metabolism ; Carbon Cycle ; Carbon Dioxide ; metabolism ; Cell Culture Techniques ; Energy Metabolism ; drug effects ; Light ; Photochemical Processes ; Synechococcus ; growth & development ; metabolism

OBJECTIVETo investigate whether vascular endothelial growth factor (VEGF) gene plasmid carried by polytetrafluoroethylene (PTFE) vascular graft materials could transfect endothelial cells (ECs) and promote their growth.

METHODSPTFE vascular graft materials carried with pCDI-hVEGF(121), pCDI or pEGFP were incubated in Tris-buffer solution and the values of optical density of 260 nm at different time were plotted, then the DNA controlled release curve was made. ECs derived from human umbilical vein were seeded on the pCDI-hVEGF(121)/pCDI/pEGFP-PTFE materials or tissue culture plates, ECs numbers were counted and VEGF protein concentrations at different time were measured by enzyme-linked immunoadsorbent assay method. Green fluorescent protein (GFP) expression in ECs on pEGFP-PTFE materials was examined with fluorescence microscopy.

RESULTSThe controlled release curve showed that the gene released from PTFE materials was rapid within 8 h, then slowed down and that the gene released continuously even after 72 h. At 24, 72 and 120 h, ECs number and proliferation rate of pCDI-hVEGF(121)-PTFE materials were higher than those of pCDI or pEGFP-PTFE materials (P<0.05). VEGF protein concentration of pCDI-hVEGF(121)-PTFE materials was higher than that of pCDI or pEGFP-PTFE materials at 6, 24, 72 and 120 h (P<0.01). GFP expression in ECs on the pEGFP-PTFE materials could be detected by fluorescence microscopy.

CONCLUSIONPTFE graft can be used as a carrier of VEGF gene plasmid, VEGF gene carried by PTFE can transfect ECs and promote ECs growth.

Blood Vessel Prosthesis ; Cell Adhesion ; physiology ; Cell Growth Processes ; physiology ; DNA ; chemistry ; genetics ; Endothelial Cells ; cytology ; physiology ; Humans ; Plasmids ; chemistry ; genetics ; Polytetrafluoroethylene ; Transfection ; methods ; Vascular Endothelial Growth Factor A ; genetics

Astrocytes play important roles in normal brain development and the physiological processes. In particular, 30% of the brain volume consists of astrocytes, and they are the primary target cell in the brain for cellular injuries from chemical exposures. The present study attempts to establish an immortalized murine astrocyte cell line to study the mechanisms of chemical-induced carcinogenesis of astrocytes. Primary astrocytes isolated from mice were transfected with plasmid carrying the SV40 T antigen. Clonal cells obtained after G418 selection were continuously subcultured to establish an immortalized astrocyte cell line. The cell line was positive on GFAP expression and was sensitive to exposure to such chemicals as MNNG. Cells were treated with MNNG for 5 days, with doses ranging from 0.001ug/ml to 1ug/ml. Dose-dependent cellular transformations of astrocytes were observed. Treatments at 0.01ug/ml showed the most distinct characteristics of neoplastic transformation. Subsequent treatment with TPA produced higher levels of neoplastic cell transformation than MNNG treatment alone, as evidenced by increases of saturation density, soft-agar colony formation and cell aggregation. Promotional effects of TPA on cell transformation was further demonstrated by the shortening duration of foci appearance. Addition of hydrocortisone to the culture media resulted in further promotion of cell transformation in astrocytes treated with MNNG and TPA, suggesting that glucocortocoid also plays a role in the promotion of chemical-induced astrocyte transformation. The present study demonstrates that astrocytes are susceptible to chemical-induced carcinogenicity and subject to mechanisms of multistage carcinogenesis. Analysis of MNNG-transformed astrocytes showed that, while the expression of TGF-beta was decreased, expression of GFAP, IL-1betaand fibronectin were increased. The results suggest that these factors are associated with mechanisms of MNNG-induced astrocyte transformation and may be used as potential candidates for biomarkers representing astrocyte-related tumors and cell toxicities. The study showed scientific evidence that growth factors, cytokine and the extracellular matrix are involved in processes of chemical-induced transformation of astrocytes. In addition, the present work provided an excellent opportunity to develop an immortalized astrocyte cell line that can be used for studying mechanisms of astrocyte-related diseases.
Animals ; Antigens, Viral, Tumor ; Astrocytes* ; Biomarkers ; Brain ; Carcinogenesis* ; Cell Aggregation ; Cell Line ; Cell Transformation, Neoplastic ; Culture Media ; Extracellular Matrix ; Fibronectins ; Hydrocortisone ; Intercellular Signaling Peptides and Proteins ; Methylnitronitrosoguanidine ; Mice ; Physiological Processes ; Plasmids ; Transforming Growth Factor beta