108 resultados para PCNA


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OBJECTIVE: This study was undertaken to assess whether fine needle aspirates from non-Hodgkins lymphoma (NHL) could be used for growth fraction analysis with proliferating cell nuclear antigen (PCNA) staining and if there was a relationship between the growth fraction and cytomorphologic classification according to the Kiel classification.STUDY DESIGN: the study group consisted of 40 patients with NHL diagnosed by fine needle aspiration (FNA) cytology. The cytologic classification of the lymphomas was made by two cytopathologists on May-Grunwald-Giemsa-stained slides using the Kiel classification. There were 27 cases of low and 13 of high grade lymphoma. The estimation of the growth fraction was made by PCNA immunoreactivity. The PCNA index was quantitated in smears by counting an average of 1,000 cells, and the count teas correlated with the cytomorphologic classification.RESULTS: There was It strong correlation between the PCNA index and lymphoma grading. High grade lymphomas exhibited a mean PCNA positivity of 74.0%, which was significantly higher (P <.001) than that of low grade lymphomas (17.6%).CONCLUSION: Our study showed that PCNA evalua tion is suitable for smears obtained by FNA on NHL, correlates with increasing grades of lymphoma according to the Kiel classification and may offer a method of monitoring treatment of lymphoma.

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To investigate the expression of a marker of cell proliferation (PCNA/Cyclin) and its putative relationship with histological grading, mitotic index and estrogen receptor immunoreactivity, we studied twenty-seven cases of invasive breast carcinoma in formalin-fixed, paraffin-embedded tissue sections. The PCNA and estrogen receptor were detected by the PC10 and H222 monoclonal antibodies respectively, using an avidin-biotin-pernxidase method. The median value of PCNA index was 20.9% with a range from 1.4 to 84.2%. We did not find any significant relationship between PCNA index anti the histological grading, mitotic index and estrogen receptor immunoreactivity. We conclude that PCNA detected by the monoclonal antibody PC10 in formalin-fixed material looks at present unrealiable as a proliferation marker in breast carcinoma.

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Taking into consideration that glutatione S-transferase (GST) and cellular proliferation play a crucial role during carcinogenesis, the goal of this study was to investigate the expression of placental GST, called GST-P, and proliferating cellular nuclear antigen (PCNA) by means of immunohistochemistry during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). This is a useful model for studying oral squamous cell carcinoma phase by phase. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution by drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. GST-P positive foci were detected in non-neoplastic oral cells at 4 weeks of 4NQO administration. In the same way, GST-P positive cells were detected in pre-neoplastic lesions and squamous cell carcinomas induced after 12 and 20 weeks-treatment, respectively. None of the control animals expressed GST-P positive cells. Regarding cellular proliferation, PCNA positive nuclei were higher at 12 and 20 weeks following 4NQO exposure (p < 0.05) when compared to negative control. These results suggest that the expression of GST-P is correlated with cellular proliferation, in which GST-P is associated with risk and progression of oral cancer, whereas PCNA is closely involved during neoplastic conversion. (c) 2007 Published by Elsevier GmbH.

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We tested the hypothesis that a panel of antibodies to cell surface, cytoplasmic, and nuclear antigens could reliably distinguish the cells composing reactive germinal centers from those composing follicular lymphoma. Immunocytochemistry was performed on deparaffinized sections of methacarn-fixed lymph node and tonsil (15 cases of reactive hyperplasia and 14 cases of follicular lymphoma) using antibodies to the nerve growth factor receptor (NGFR5), bcl-2 protein (124), proliferating cell nuclear antigen (PCNA; 19A2), and CD45RA (MT2). In 100% of cases of reactive hyperplasia, both MT2 and 124 showed positive immunostaining of mantle zone and scattered interfollicular lymphocytes, but in all cases there was a sharply demarcated absence of immunostaining of germinal center cells. However, diffuse immunostaining of follicular centers with MT2 (64%) and 124 (93%) and scattered intervening cells were seen in follicular lymphoma. The combination of antibodies to CD45RA and bcl-2 yielded positive immunostaining of follicular center cells in 93% of follicular lymphomas. The germinal center cells of reactive hyperplasia showed >75% nuclear positivity with antibodies to PCNA, in contrast to the follicular lymphoma cells, which showed variable PCNA indices ranging from 25 to >75%. A minority of follicular lymphoma cases (29%) showed PCNA indices comparable with those seen in cases of reactive hyperplasia. Antibodies to NGFR were positive in all cases of reactive hyperplasia and in 79% of cases of follicular hyperplasia, although the immunostaining intensity was generally decreased in follicular hyperplasia. In summary, antibodies to bcl-2 appear to be superior to those to CD45RA in distinguishing reactive hyperplasia from follicular lymphoma. Reactive hyperplasia cannot be discriminated from follicular hyperplasia using antibodies to PCNA or to nerve growth factor receptor.

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1. Cell proliferation is of interest since abnormal cell proliferation appears to be a precursor of tumorigenesis and also because the quantitative description of cell proliferation in tumors can be used to predict the biological behavior of a particular neoplasia.2. Them am several reliable methods of studying cell proliferation in tissues. One of the most important is the detection of the Ki67 defined antigen in frozen sections. The number of cells expressing Ki67 correlates with histological grades of tumors and can also be predictive of clinical outcome. The Ki67 can be localized in tissue sections using monoclonal antibodies in association with the immunoperoxidase technique.3. Proliferating cell nuclear antigen (PCNA) is a component of DNA polymerase-delta and is another important cell proliferation marker manifesting a striking increase in concentration during the S phase of the cell cycle. 19A2 and PC10 are two different monoclonal antibodies which can be employed to detect PCNA in paraffin-embedded tissues.4. Molecular biology has also been making a great contribution to the study of cell proliferation. The most recent innovation in tissue identification of proliferating cells is the use of in situ hybridization for the localization of histone H3 and/or H4 mRNA. H3 mRNA-positive cells appear to be present in basal cells of the skin and in crypt cells of the intestine which are sites with high proliferation rate.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The different potential of initiated and non-initiated urinary bladder mucosa (UBM) to develop neoplasia was quantitatively evaluated in the male Wistar rat. Initiation of carcinogenesis was accomplished with N-butyl-N-(4- hydroxybutyl)-nitrosamine (BBN). Stimuli for cell proliferation and apoptosis were obtained by exposure followed by withdrawal of 3% Uracil in the diet. The proliferation index (PI) was estimated in UBM immunostained for the proliferating nuclear cell antigen (PCNA). The apoptotic index (AI) and the density of papillary/nodular hyperplasia (PNH) were estimated in hematoxilin- eosin stained sections. PNH was the main proliferative response to the mechanical irritation by uracil, irrespective of previous initiation with BBN. Uracil exposure induced higher PI and PNH density in the initiated rats. After uracil withdrawal, there was a significant increase of the AI in both uracil-treated groups, which correlated well to the respective PNH density. However, at the end of the experiment, PNH incidence and density were significantly higher in the BBN-initiated mucosa, which also presented 18% incidence of papillomas and 27% of carcinomas. Therefore, under prolonged uracil calculi trauma, the UBM of BBN-initiated Wistar rats gives rise to epithelial proliferative lesions that progress to neoplasia through acquired resistance to apoptosis.

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The knowledge of cell-cycle control has shown that the capacity of malignant growth is acquired by the stepwise accumulation of defects in specific genes regulating cell growth. Histologic diagnosis might be improved by a quantitative evaluation of more specific diagnosis biomarkers, which could help to precisely identify pre-malignant and malignant oral lesions. The aim of the present study is to evaluate whether computer-based quantitative assessment of p53, PCNA and Ki-67 immunohistochemical expression, could be used clinically to foresee the risk of oral malignant transformation. This retrospective study was carried out in ninety-five oral biopsies, 27 were classified as fibrous inflammatory hyperplasia, 40 as leukoplakia and 28 as oral squamous cell carcinoma. Sixteen out of the 40 leukoplakia were diagnosed as non-dysplastic leukoplakia, the other 24 being dysplastic leukoplakia, of which 50.0% were classified as moderate to severe dysplasia. Comparison of the four groups of oral tissues showed significant rises in p53 and Ki-67 positivity index, which increased steadily in the order benign, pre-malignant, and malignant. In contrast, it was not possible to relate higher PCNA levels with pre-malignant and malignant oral lesions. We therefore conclude that PCNA immunohistochemistry expression is probably an inappropriate marker to identify oral carcinogenesis, whereas joint quantitative evaluation of p53 and Ki-67, appears to be useful as a tumor marker, providing a pre-diagnostic estimate of the potential for cell-cycle deregulation of the oral proliferate status.

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We investigated the effects of doxazosin (Dox), an alpha-adrenoceptor antagonist used clinically for the treatment of benign prostatic hyperplasia (BPH), on the rat prostatic complex by assessing structural parameters, collagen fiber content, cell proliferation, and apoptosis. Adult Wistar rats were treated with Dox (25 mg/kg per day), and the ventral (VP), dorsolateral, and anterior prostate (AP) regions of the prostate complex were excised at 3, 7, and 30 days after treatment. At 24 h before being killed, the rats were injected once with 5-bromodeoxyuridine (BrdU; thymidine analog) to label mitotically active cells. The prostates were weighed and processed for histochemistry, morphometry-stereology, immunohistochemistry for BrdU, Western blotting for proliferating cell nuclear antigen (PCNA), and the TUNEL reaction for apoptosis. Dox-treated prostate lobes at day 3 presented increased weight, an enlarged ductal lumen, low cubical epithelial cells, reduced epithelial folds, and stretched smooth muscle cells. However, at day 30, the prostates exhibited a weight reduction of ∼20% and an increased area of collagen and reticular fibers in the stromal space. Dox also reduced epithelial cell proliferation and increased apoptosis in the three prostatic lobes. Western blotting for PCNA confirmed the reduction of cell proliferation by Dox, with the AP and VP being more affected than the dorsal prostate. Thus, Dox treatment alters epithelial cell behavior and prostatic tissue mechanical demand, inducing tissue remodeling in which collagen fibers assume a major role. © 2007 Springer-Verlag.

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The objective of this study was to evaluate the effects of adding ascorbic acid to the media for in vitro culture of cattle ovarian fragments and to determine their effects on growth activation and viability of early-stage follicles. The ovarian cortex was divided into small fragments; one fragment was immediately fixed (control) and the other fragments were cultured in minimum essential medium (MEM) supplemented or not with various doses of ascorbic acid. Ovarian tissue was processed for histology, transmission electron microscopy (TEM) and immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA). Compared with control fragments, the percentage of primordial follicles was reduced (p < 0.05) and the percentage of growing follicles had increased (p < 0.05) in cultured cortical fragments, independent of the tested medium or incubation time. Furthermore, compared with control tissue, culture of ovarian cortex for 8 days reduced the percentages of healthy, viable follicles (p < 0.05), but not when cultures were supplemented with 25, 50 or 100 μg/ml of ascorbic acid. Ultrastructural and immunohistochemical analysis of 8 day cultured ovarian cortical fragments, however, showed the integrity and viability of follicles only when fragments were cultured in presence of 50 μg/ml of ascorbic acid. In conclusion, this study demonstrated that addition of ascorbic acid to MEM at a concentration of 50 μg/ml not only stimulates the activation of 8 day in vitro cultured cattle primordial follicles and subsequent growth of activated follicles, but also safeguards the viability of these early-stage follicles. © 2012 Copyright Cambridge University Press.

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Bullfrog stem spermatogonia, also named primordial germ cells (PGCs), show strong testosterone immunolabeling in winter, but no or weak testosterone immunoexpression in summer. Thus, the role of testosterone in these cells needs to be clarified. In this study, we proposed to evaluate whether PGCs express aromatase and estrogen receptors, and verify a possible role of estrogen in PGCs seasonal proliferation. Testes of male adult bullfrogs, collected in winter (WG) and summer (SG), were fixed and embedded in historesin, for quantitative analysis, or paraffin for immunohistochemistry (IHC). The number of haematoxylin/eosin stained PGCs/lobular area was obtained. Proliferating cell nuclear antigen (PCNA), aromatase, estrogen receptor β (ERβ) and PCNA/ERβ double immunolabeling were detected by IHC. The number of PCNA-positive PGCs and the histological score (HSCORE) of aromatase and ERβ immunolabeled PGCs were obtained. Although the number of PGCs increased significantly in WG, a high number of PCNA-positive PGCs was observed in summer. Moreover, aromatase and ERβ HSCORE was higher in SG than WG. The results indicate that PGCs express a seasonal proliferative activity; the low mitotic activity in winter is related to the maximal limit of germ cells which can be supported in the large lobules. In SG, the increased ERβ and aromatase HSCORE suggests that testosterone is converted into estrogen from winter to summer. Moreover, the parallelism between the high PGCs mitotic activity and ERβ immunoexpression suggest a participation of estrogen in the control of the PGCs seasonal proliferative activity which guarantee the formation of new germ cysts from summer to next autumn. © 2012 Elsevier Inc.

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This study evaluated the influence of bone marrow aspirate (BMA), low-level laser therapy (LLLT) and their combination on bone healing in surgically created critical-size defects (CSDs) in rat calvaria. 40 rats were divided into four groups: C (control), BMA, LLLT and BMA/LLLT. A 5 mm diameter CSD was created in the calvarium of each animal. In Group C, the defect was filled by blood clot only. In Group BMA, the defect was filled with BMA. In groups LLLT and BMA/LLLT, the defect received laser irradiation (InGaAlP laser), was filled with blood clot or BMA respectively, and irradiated again. Animals were euthanized 30 days postoperatively. Histomorphometric and immunohistochemical analyses were performed. Newly formed bone area (NFBA) was calculated as percentage of the total area of the original defect. Proliferating cell nuclear antigen (PCNA), runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) immunohistochemical staining were performed. PCNA-positive, Runx2-positive and OCN-positive cells were quantified. Data were statistically analyzed. Group BMA/LLLT had significantly greater NFBA than groups C, BMA or LLLT. Group BMA presented significantly greater NFBA than control, while group LLLT did not. Group BMA/LLLT presented a significantly higher number of PCNA-positive and OCN-positive cells than any of the other groups. Groups BMA/LLLT and BMA showed a significantly lower number of Runx2-positive cells than groups C or LLLT. The combination of BMA/LLLT yielded significantly greater bone formation in surgically created CSD in rat calvaria when compared to control, or either treatment alone. © 2013 Elsevier B.V. All rights reserved.

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The female prostate is a differentiated organ found in several mammal species, including humans and rodents. This gland has been related to important functions on female reproductive biology. Although the factors, which regulate prostate's development and activity are not well known, its functionality has been related to steroid hormones. It is well established that cyclic changes of estradiol and progesterone levels promote histophysiological adaptations of the whole female body. In contrast, only a few is found about those adaptations in female prostate. Thus, this study aimed to evaluate the effect of estradiol and estradiol+testosterone association on gerbil female prostate in order to verify, which hormonal associations are necessary to its homeostasis. For this, adult females had the ovaries surgically removed. After recovering, they received estradiol and estradiol+testosterone doses through 30 days, each 48 h. The prostatic tissue underwent morphological and morphometric-estereological analysis. Hormonal restriction caused great gland involution and decreased secretory activity, aspects that were reverted by exposure to estradiol and estradiol+testosterone. However, these hormones were not able to re-establish the normal prostate histoarchitecture. The immunoreaction of steroid receptors (ER-α, ER-β, and AR) responded differently among the experimental and control groups, and PCNA assay showed a decrease in epithelial cell proliferation within groups that had hormone privation. Therefore, we conclude that estradiol and testosterone are able to influence prostate morphophysiology and the maintenance of gland homeostasis depends on a balance among these and other hormones. © 2013 Wiley Periodicals, Inc.

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Artibeus planirostris is an endemic species of Phyllostomid bat from the Neotropical region. Some studies have indicated that it exhibits seasonal bimodal polyestry; however, others postulate that it may be able to produce young at any time during the year. Thus, the aim of this study was to evaluate the annual variations in testicular and epididymal parameters of this species in southeast Brazil and try to understand how the reproduction of this species is regulated in this environment. Sixty mature male specimens, collected between June 2009 and May 2010, were submitted to morphometric and immunohistochemical analysis. Our study showed that A. planirostris presented a continuously active pattern of spermatogenesis throughout the year, presenting spermatozoa inside its cauda epididymis in all months, but with two pronounced peaks of spermatogenic production, one in September and other in February. We propose that the males developed these two peaks in order to produce sufficient sperm for the reproduction in a harem system and to synchronize with the female reproductive cycle, which had a bimodal polyestric pattern. Control of this variation is directly linked to the expression of the androgen receptor (AR) in Sertoli cells and to serum testosterone levels, which appear to synchronize to establish these two peaks. In the months preceding the two peaks, the testis have a higher expression of the AR, which possibly stimulates the increase in PCNA, and drives a gradual increase in the testicular parameters. Taken together the results suggest that if sperm storage happens in this species, it is of short duration. © 2013 Elsevier Inc.

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Background: Ginkgo biloba extract (GbE) is used extensively by breast cancer patients undergoing treatment with Tamoxifen (TAM). Thus, the present study investigated the effects of GbE in female Sprague-Dawley (SD) rats bearing chemically-induced mammary tumors and receiving TAM.Methods: Animals bearing mammary tumors (≥1 cm in diameter) were divided into four groups: TAM [10 mg/kg, intragastrically (i.g.)], TAM plus GbE [50 and 100 mg/kg, intraperitoneally (i.p.)] or an untreated control group. After 4 weeks, the therapeutic efficacy of the different treatments was evaluated by measuring the tumor volume (cm3) and the proportions of each tumor that were alive, necrotic or degenerative (mm2). In addition, labeling indexes (LI%) were calculated for cell proliferation (PCNA LI%) and apoptosis (cleaved caspase-3 LI%), expression of estrogen receptor-alpha (ER-α) and p63 biomarkers.Results: Overall, the tumor volume and the PCNA LI% within live tumor areas were reduced by 83% and 99%, respectively, in all TAM-treated groups when compared to the untreated control group. GbE treatment (100 mg/kg) reduced the proportions of live (24.8%) and necrotic areas (2.9%) (p = 0.046 and p = 0.038, respectively) and significantly increased the proportion of degenerative areas (72.9%) (p = 0.004) in mammary tumors when compared to the group treated only with TAM. The expression of ER-α, p63 and cleaved caspase-3 in live tumor tissues was not modified by GbE treatment.Conclusions: Co-treatment with 100 mg/kg GbE presented a slightly beneficial effect on the therapeutic efficacy of TAM in female SD rats bearing mammary tumors. © 2013 Dias et al.; licensee BioMed Central Ltd.