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Proliferation Potential (proliferation + potential)

Distribution by Scientific Domains
Medical Sciences83%

Selected Abstracts

Proliferation Potential in Recurrent Acoustic Schwannoma Following Gamma Knife Radiosurgery versus Microsurgery,

THE LARYNGOSCOPE, Issue 6 2002
Frank Lee MD
Abstract Objective To evaluate the proliferation potential of recurrent acoustic schwannoma following gamma knife radiosurgery (GKR) versus microsurgery. Study Design Retrospective study. Methods A review of surgical records of the House Ear Clinic revealed 8 patients who had undergone GKR and 15 patients who had undergone microsurgery who had unilateral acoustic schwannoma recurrences. Immunohistochemical studies were performed to evaluate the expression of proliferating cell nuclear antigen (PCNA) on archival paraffin-embedded blocks. Results All 8 GKR and 15 microsurgical tumors had positive staining for PCNA. The recurrent GKR tumors had significantly lower proliferation levels than in the microsurgical group (P = .03). Two GKR tumors had high proliferation levels. Conclusions Our study indicates that recurrent vestibular schwannomas treated with GKR have lower proliferation potential as assessed by PCNA compared with recurrences following microsurgery. Radiation-induced apoptosis is thought to contribute to the lower tumor cell proliferation in GKR tumor. The two GKR tumors with high proliferation potential could be a result of radiation-induced sporadic mutation, resulting in high tumor cell proliferation. [source]

Ex vivo differentiation of umbilical cord blood progenitor cells in the presence of placental conditioned medium

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2002
Mihaela Chivu
Abstract Hematopoetic stem cells (HSC) are the progenitors for the lympho-hematopoietic system, with long lifespan and high proliferation potential. Transplantation of HSC from bone marrow or peripheral blood represents a standard therapy in severe hematological conditions. A possible alternative source of HSC is the umbilical cord blood, prepared by various separation procedures followed by expansion in cultures supplemented with hematopoietic growth factors. In order to check the effects of placental conditioned medium (PCM) from placental cells culture upon viability of HSC, we added plasma, PCM, dimetil sulfoxyde or hemin in HSC cultures. Flow cytometry or direct scoring of solid cultures using CD45+, CD34+, CD71+ and CD14+ fluorescent-labeled monoclonal antibodies evaluated the effects upon cell proliferation and colony forming ability of HSC cultures, versus controls. PCM produced the highest proliferation, followed by plasma, DMSO and hemin. PCM improved the survival time and maintained a higher proportion of immature cells. PCM stimulates the differentiation towards myeloid lineage progenitor cells (>90% being CD45+), increasing the percentage of CD14+, granulocites /monocytes precursors. It is highly suggestive that PCM contains growth factors or cytokines, which regulate the development of HSC. Characterization of these factors is in progress. [source]

Histopathological and immunohistochemical analysis of calcifying odontogenic cysts

JOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 10 2001
Mitsuhide Yoshida
Abstract: Method and Results: Calcifying odontogenic cysts (COCs) were examined histopathologically and immunohistochemically to characterize the histological and cytological properties of these lesions. Histopathologically, COCs showed thin or thick lining epithelium with ghost cells. COCs were classified according to proliferative type or nonproliferative type lining epithelium, the presence or absence of ameloblastomatous appearance, and the presence or absence of odontoma in the cyst walls. Immunohistochemically, amelogenin protein was expressed chiefly in ghost cells, whereas cytokeratin 19 (CK19) and bcl-2 proteins were expressed chiefly in lining epithelial cells. The proportion of cases positive for bcl-2 protein was slightly higher in COCs with odontoma than in those without odontoma. Lining epithelial cells sporadically showed positive reactions for Ki-67 antigen. Mean Ki-67 labeling index was slightly greater in COCs with proliferative type lining epithelium, COCs with ameloblastomatous appearance of the cyst walls, and COCs with odontoma of the cyst walls than in COCs without these histological features. Our results suggest that ghost cells or lining epithelial cells show ameloblastic cytodifferentiation or odontogenic epithelial characteristics, that bcl-2 protein is associated with survival of lining epithelial cells in COCs, and that high proliferation potential is associated with ameloblastomatous proliferation or combined odontoma. COCs exhibited various histological features with several transitional forms, and immunohistochemical examinations revealed little or no difference in cytodifferentiation and cellular activity among COCs. Conclusion: We conclude that COCs with various histological features have neoplastic potential and may not be separate entities within the same histological spectrum. [source]

Proliferation Potential in Recurrent Acoustic Schwannoma Following Gamma Knife Radiosurgery versus Microsurgery,

THE LARYNGOSCOPE, Issue 6 2002
Frank Lee MD
Abstract Objective To evaluate the proliferation potential of recurrent acoustic schwannoma following gamma knife radiosurgery (GKR) versus microsurgery. Study Design Retrospective study. Methods A review of surgical records of the House Ear Clinic revealed 8 patients who had undergone GKR and 15 patients who had undergone microsurgery who had unilateral acoustic schwannoma recurrences. Immunohistochemical studies were performed to evaluate the expression of proliferating cell nuclear antigen (PCNA) on archival paraffin-embedded blocks. Results All 8 GKR and 15 microsurgical tumors had positive staining for PCNA. The recurrent GKR tumors had significantly lower proliferation levels than in the microsurgical group (P = .03). Two GKR tumors had high proliferation levels. Conclusions Our study indicates that recurrent vestibular schwannomas treated with GKR have lower proliferation potential as assessed by PCNA compared with recurrences following microsurgery. Radiation-induced apoptosis is thought to contribute to the lower tumor cell proliferation in GKR tumor. The two GKR tumors with high proliferation potential could be a result of radiation-induced sporadic mutation, resulting in high tumor cell proliferation. [source]

Thrombopoietin, flt3-ligand and c-kit-ligand modulate HOX gene expression in expanding cord blood CD133+ cells

CELL PROLIFERATION, Issue 4 2004
C. P. McGuckin
Extrinsic modulators include growth factors and cell adhesion molecules, whereas intrinsic regulation is achieved with many transcription factor families, of which the HOX gene products are known to be important in haemopoiesis. Umbilical cord blood CD133+ HSPC proliferation potential was tested in liquid culture with ,TPOFLK' (thrombopoietin, flt-3 ligand and c-kit ligand, promoting HSPC survival and self-renewal), in comparison to ,K36EG' (c-kit-ligand, interleukins-3 and -6, erythropoietin and granulocyte colony-stimulating factor, inducing haemopoietic differentiation). TPOFLK induced a higher CD133+ HSPC proliferation (up to 60-fold more, at week 8) and maintained a higher frequency of the primitive colony-forming cells than K36EG. Quantitative polymerase chain reaction analysis revealed opposite expression patterns for specific HOX genes in expanding cord blood CD133+ HSPC. After 8 weeks in liquid culture, TPOFLK increased the expression of HOX B3, B4 and A9 (associated with uncommitted HSPC) and reduced the expression of HOX B8 and A10 (expressed in committed myeloid cells) when compared to K36EG. These results suggest that TPOFLK induces CD133+ HSPC proliferation, self-renewal and maintenance, up-regulation of HOX B3, B4 and A9 and down-regulation of HOX B8 and A10 gene expression. [source]