Search results for "ki-67"
showing 10 items of 94 documents
Immunohistochemical evaluation of growth fractions in human breast cancers using monoclonal antibody Ki-67.
1991
We performed immunohistochemical analyses of 568 breast/cancer specimens using Ki-67, a monoclonal antibody specific for a nuclear antigen present in proliferating cells. The specimens were divided into three groups (I-III) according to the proportion of Ki-positive cells detected. These findings were compared with features of tumor extension as well as with certain prognostic variables. There was no detectable correlation between Ki-67 reactivity and either tumor size or node involvement. In contrast, a statistically significant correlation was found between Ki-67 reactivity and tumor grading, in that G-I tumors had small growth fractions, while a high proportion of G-III tumors exhibited …
Transcriptional repression of Bmp2 by p21(Waf1/Cip1) links quiescence to neural stem cell maintenance.
2013
Relative quiescence and self renewal are defining features of adult stem cells, but their potential coordination remains unclear. Subependymal neural stem cells (NSCs) lacking cyclin-dependent kinase (CDK) inhibitor (CKI) 1a (p21) exhibit rapid expansion that is followed by their permanent loss later in life. Here we demonstrate that transcription of the gene encoding bone morphogenetic protein 2 (Bmp2) in NSCs is under the direct negative control of p21 through actions that are independent of CDK. Loss of p21 in NSCs results in increased levels of secreted BMP2, which induce premature terminal differentiation of multipotent NSCs into mature non-neurogenic astrocytes in an autocrine and/or …
Prognostic Value of p53, p21/WAF1, Bcl-2, Bax, Bak and Ki-67 Immunoreactivity in pT1 G3 Urothelial Bladder Carcinomas
2001
pT1 G3 bladder carcinomas are heterogeneous with respect to tumor recurrence and progression. Whereas some urologists treat these carcinomas by repeated transurethral resections often followed by intravesical chemotherapy or BCG instillation, others recommend cystectomy after tumor recurrence or early cystectomy after the initial diagnosis. Our goal was to determine the prognostic value of p53, p21/WAF1, Bcl-2, Bax, Bak, and Ki-67 immunoreactivity in these tumors. There were 30 patients with a new histopathological diagnosis of pT1 G3 urothelial carcinoma based on a transurethral resection specimen. Representative sections of these specimens were examined for the above markers. All patients…
Chronic fluoxetine treatment in middle-aged rats induces changes in the expression of plasticity-related molecules and in neurogenesis
2012
Abstract Background Antidepressants promote neuronal structural plasticity in young-adult rodents, but little is known of their effects on older animals. The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) may mediate these structural changes through its anti-adhesive properties. PSA-NCAM is expressed in immature neurons and in a subpopulation of mature interneurons and its expression is modulated by antidepressants in the telencephalon of young-adult rodents. Results We have analyzed the effects of 14 days of fluoxetine treatment on the density of puncta expressing PSA-NCAM and different presynaptic markers in the medial prefrontal cortex, hippocampus and amygdala of mi…
Chronic non-invasive glucocorticoid administration decreases polysialylated neural cell adhesion molecule expression in the adult rat dentate gyrus
2004
The expression of the polysialylated neural cell adhesion molecule (PSA-NCAM) is increased in the hippocampus after chronic restraint stress (CRS) and may play a permissive role in structural changes that include dendrite reorganization in dentate gyrus (DG) and CA3 pyramidal neurons and suppression of neurogenesis in DG. We report that chronic oral corticosterone (CORT) administration decreases the number of PSA-NCAM immunoreactive granule neurons in the adult rat dentate gyrus, and the available evidence suggests that this is an indirect effect of CORT, possibly involving excitatory amino acids, that may not be directly related to neurogenesis. Because CORT treatment reduces but does not …
Chronic cocaine exposure impairs progenitor proliferation but spares survival and maturation of neural precursors in adult rat dentate gyrus
2006
Recent observations indicate that drugs of abuse, including alcohol and opiates, impair adult neurogenesis in the hippocampus. We have studied in rats the impact of cocaine treatment (20 mg/kg, daily, i.p.) on cell proliferation, survival and maturation following short-term (8-day) and long-term (24-day) exposure. Using 5'-bromo-2-deoxyuridine (BrdU) and Ki-67 as mitotic markers at the end of the drug treatments, we found that both short- and long-term cocaine exposures significantly reduced cell proliferation in the dentate gyrus (DG) of the hippocampus. By labelling mitotic cells with BrdU pulses before or during the early stages of the drug treatment, we determined that long-term cocaine…
Binge administration of 3,4-methylenedioxymethamphetamine ("ecstasy") impairs the survival of neural precursors in adult rat dentate gyrus.
2006
3,4-Methylenedioxymethamphetamine (MDMA) is a potent stimulant and hallucinogenic drug whose ability to regulate neurogenesis in the adult has not been previously investigated. We used 5'-bromo-2-deoxyuridine (BrdU) and Ki-67 as mitotic markers, and doublecortin (DCX) as a marker of immature neurons, to study proliferation, survival and maturation of adult-generated cells in the dentate gyrus (DG) of the hippocampus following binge administration of MDMA (8 injections of 5 mg/kg at 6 h intervals). The results showed that MDMA treatment did not affect cytogenesis in the DG, but significantly decreased the survival rate of cells incorporated after 2 weeks to the granular layer of the DG by ca…
p16INK4A (CDKN2A) gene deletion is a frequent genetic event in synovial sarcomas.
2006
We assessed the frequency of genomic deletion of p16 INK4A (CDKN2A) in synovial sarcomas (SSs) and its possible association with immunoexpression of p16 and cyclin D1 and the Ki-67 proliferation index using dualcolor fluorescence in situ hybridization (FISH) on tissue microarray sections of 41 histologically and molecularly confirmed SSs. A heterozygous p16 INK4A gene deletion was identified in 28 (74%) of 38 cases, with 25 (89%) of them showing abnormal p16 protein expression (20 negative and 5 heterogeneous). Of 25 cases, 19 (76%) exhibiting increased cyclin D1 expression also demonstrated heterozygous p16 INK4A deletion. No significant association was observed between p16 INK4A deletion …
Expresión proteica de p53 y proliferación celular en leucoplasias orales
2005
Objetivos: Conocer la expresión proteica de las alteraciones genéticas que se producen en las etapas precoces de la cancerización del campo de cavidad oral en nuestro medio. Estudiar la proliferación celular mediante Ki-67 y la expresión de la proteína p53 para valorar si las alteraciones en la expresión proteica de estos marcadores suceden de forma secuencial a través de las distintas etapas en la cancerización del campo de la cavidad oral. Material y métodos: Se realizó un estudio mediante técnicas de inmunohistoquímica sobre 53 pacientes que presentaron lesiones de leucoplasia oral, atendidos por el Servicio de O.R.L del Hospital Universitario de Salamanca, desde 1.990 hasta 2000. Se inc…
Trastuzumab therapy vs tetracycline controlled ERBB2 downregulation: influence on tumour development in an ERBB2-dependent mouse tumour model
2008
Trastuzumab (Herceptin) has improved therapy of breast cancer. Only patients overexpressing ERBB2 are treated with trastuzumab, whereas its use in tumours without ERBB2 expression is useless. This led to the concept that the subgroup of trastuzumab-sensitive tumours is ‘ERBB2-dependent', meaning that ERBB2 signalling is indispensable for growth of these tumours. We used a mouse model that allows anhydrotetracycline (ATc)-controlled downregulation of ERBB2 in tumour tissue. ERBB2 mRNA and protein expression were downregulated below detection limit leading to a macroscopically complete tumour remission within 14 days. Tumour remission was accompanied by a strong decrease in proliferation, a m…