Home About us Contact
|
Home About us Contact | ||
|
|
||
Active Proliferation (active + proliferation)
Selected AbstractsPhyllodes tumor of the prostate: Recurrent obstructive symptom and stromal proliferative activityINTERNATIONAL JOURNAL OF UROLOGY, Issue 9 2004KOJI SHIRAISHI Abstract We report the case of a 59-year-old man with a metachronous development of phyllodes tumor and adenocarcinoma of the prostate. He complained of urinary obstruction and transurethral resections of the prostate (TUR-P) had been performed six times in 10 years. Microscopic examination showed cystically dilated glands consisting of bizarre cells with pleomorphic, hyperchromatic nuclei in the stroma at the sixth TUR-P. Radical prostatectomy was performed against recurrences and adenocarcinoma was incidentally detected. Apparent up-regulation of proliferative nuclear antigens (PCNA), but not p53, was observed in the prostatectomy specimen by Western blotting. Active proliferation of stromal cells is considered to have caused the recurrent obstructive symptom. [source] Non-antagonistic relationship between mitogenic factors and cAMP in adult Schwann cell re-differentiationGLIA, Issue 9 2009Paula V. Monje Abstract The expression of myelination-associated genes (MGs) can be induced by cyclic adenosine monophosphate (cAMP) elevation in isolated Schwann cells (SCs). To further understand the effect of known SC mitogens in the regulation of SC differentiation, we studied the response of SCs isolated from adult nerves to combined cAMP, growth factors, including neuregulin, and serum. In adult SCs, the induction of MGs by cAMP coincided with the loss of genes expressed in non-myelin-forming SCs and with a change in cell morphology from a bipolar to an expanded epithelial-like shape. Prolonged treatment with high doses of cAMP-stimulating agents, as well as low cell density, was required for the induction of SC differentiation. Stimulation with serum, neuregulin alone, or other growth factors including PDGF, IGF and FGF, increased SC proliferation but did not induce the expression of MGs or the associated morphological change. Most importantly, when these factors were administered in combination with cAMP-stimulating agents, SC proliferation was synergistically increased without reducing the differentiating activity of cAMP. Even though the initiation of DNA synthesis and the induction of differentiation were mostly incompatible events in individual cells, SCs were able to differentiate under conditions that also supported active proliferation. Overall, the results indicate that in the absence of neurons, cAMP can trigger SC re-differentiation concurrently with, but independently of, growth factor signaling. © 2008 Wiley-Liss, Inc. [source] Infancy is not a quiescent period of testicular developmentINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2001Héctor E. Chemes Postnatal evolution of the testis in most laboratory animals is characterized by the close continuity between neonatal activation and pubertal development. In higher primates, infancy, a long period of variable duration, separates birth from the beginning of puberty. This period has been classically considered as a quiescent phase of testicular development, but is actually characterized by intense, yet inapparent activity. Testicular volume increases vigorously shortly after birth and in early infancy due to the growth in length of seminiferous cords. This longitudinal growth results from active proliferation of infantile Sertoli cells which otherwise display a unique array of functional capabilities (oestrogen and anti-müllerian hormone secretion, increase of FSH receptors and maximal response to FSH). Leydig cells also show recrudescence after birth, possibly determined by an active gonadotrophic-testicular axis which results in increased testosterone secretion of uncertain functional role. This postnatal activation slowly subsides during late infancy when periodic phases of activation of the hypothalamo-pituitary-testicular axis are paralleled by incomplete spermatogenic spurts. The beginning of puberty is marked by the simultaneous reawakening of Leydig cell function and succeeding phases of germ cell differentiation/degeneration which ultimately lead to final spermatogenic maturation. The marked testicular growth in this stage is due to progressive increase at seminiferous tubule diameter. Sertoli cells, which have reached mitotic arrest, develop and differentiate, establishing the seminiferous tubule barrier, fluid secretion and lumen formation, and acquiring cyclic morphological and metabolic variations characteristic of the mature stage. All of these modifications indicate that, far from being quiescent, the testis in primates experiences numerous changes during infancy, and that the potential for pubertal development and normal adult fertility depends on the successful completion of these changes. [source] Content of endoplasmic reticulum and Golgi complex membranes positively correlates with the proliferative status of brain cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2009David C. Silvestre Abstract Although the molecular and cellular basis of particular events that lead to the biogenesis of membranes in eukaryotic cells has been described in detail, understanding of the intrinsic complexity of the pleiotropic response by which a cell adjusts the overall activity of its endomembrane system to accomplish these requirements is limited. Here we carried out an immunocytochemical and biochemical examination of the content and quality of the endoplasmic reticulum (ER) and Golgi apparatus membranes in two in vivo situations characterized by a phase of active cell proliferation followed by a phase of declination in proliferation (rat brain tissue at early and late developmental stages) or by permanent active proliferation (gliomas and their most malignant manifestation, glioblastomas multiforme). It was found that, in highly proliferative phases of brain development (early embryo brain cells), the content of ER and Golgi apparatus membranes, measured as total lipid phosphorous content, is higher than in adult brain cells. In addition, the concentration of protein markers of ER and Golgi is also higher in early embryo brain cells and in human glioblastoma multiforme cells than in adult rat brain or in nonpathological human brain cells. Results suggest that the amount of endomembranes and the concentration of constituent functional proteins diminish as cells decline in their proliferative activity. © 2008 Wiley-Liss, Inc. [source] Seeding density modulates migration and morphology of rabbit chondrocytes cultured in collagen gelsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2009Ali Baradar Khoshfetrat Abstract The cultures of rabbit chondrocytes embedded in collagen gels were conducted to investigate the cell behaviors and consequent architectures of cell aggregation in an early culture phase. The chondrocyte cells seeded at 1.0,×,105 cells/cm3 underwent a transition to spindle-shaped morphology, and formed the loose aggregates with a starburst shape by means of possible migration and gathering. These aggregates accompanied the poor production of collagen type II, while the cells seeded at 1.6,×,106 cells/cm3 exhibited active proliferation to form the dense aggregates rich in collagen type II. Stereoscopic observation was performed at 5 days to define the migrating cells in terms of a morphology-relating parameter of sphericity determined for individual cells in the gels. The frequency of migrating cells decreased with increasing seeding density, while the frequency of dividing cells showed the counter trend. The culture seeded at 1.0,×,105 cells/cm3 gave the migrating cell frequency of 0.25, the value of which was 25 times higher than that at 1.6,×,106 cells/cm3. In addition, the analysis of mRNA expression revealed that the chondrocyte cells seeded at 1.0,×,105 cells/cm3 showed appreciable down-regulation in collagen type II relating to differentiation and up-regulation in matrix metalloproteinases relating to migration, as compared to the cells seeded at 1.6,×,106 cells/cm3. These data supports the morphological analyses concerning the cell migration and aggregate formation in the cultures with varied seeding densities. It is concluded that the seeding density is an important factor to affect the cell behaviors and architecture of aggregates and thereby to modulate the quality of cultured cartilage. © 2008 Wiley Periodicals, Inc. Biotechnol. Bioeng. 2009;102: 294,302. © 2008 Wiley Periodicals, Inc. [source] | |||||||||||||