Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the expression of three cell proliferation-associated antigens: DNA polymerase alpha, Ki-67 antigen, and transferrin receptor, in 35 T-cell lymphomas of nodal origin (T-NL) and 40 cutaneous T-cell lymphomas (CTCL). Immunohistochemical staining was carried out on frozen tissue sections of these specimens using three monoclonal antibodies, DAKO-PC, CL22-2-42B (DNA polymerase alpha), and OKT9. The proportion of cells positive for CL22-2-42B, DAKO-PC, or OKT9 among all tumor cells was correlated with four histologic subtypes: malignant lymphoma (ML), diffuse, small; mixed; large; and large cell immunoblastic in both T-NL and CTCL. A strong correlation was noted between positivity for CL22-2-42B and that for DAKO-PC or OKT9. On the other hand, no difference in the expression of these three antigens was noted between T-NL and CTCL in the high, intermediate or low grade-malignancy group. In CTCL as well as in T-NL, cells positive for CL22-2-42B, DAKO-PC or OKT9 were significantly more numerous in the high-grade group than the intermediate-grade group, and in the intermediate-grade group than the low-grade group. Furthermore, a significant correlation between survival period and the number of CL22-2-42B-positive cells was noted when the T cell malignancies, CTCL and T-NL were considered (t value = 2.015, p less than 0.05). Thus, the expression of DNA-polymerase alpha, Ki-67 antigen or OKT9 seems to well reflect the biological behavior and/or clinical prognosis of T-cell lymphoma.
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PMID:Expression of three cell proliferation-associated antigens, DNA polymerase alpha, Ki-67 antigen and transferrin receptor in nodal and cutaneous T-cell lymphomas. 175 49

The proliferative capacity of brain-tumor cells was analyzed in vitro and in situ using monoclonal antibody (MAb) against deoxyribonucleic acid (DNA) polymerase alpha. For the in vitro studies, two cultured human glioma cell lines were investigated using MAb against DNA polymerase alpha, the MAb Ki-67, a serum against proliferating cell nuclear antigen (PCNA/cyclin), bromodeoxyuridine (BUdR), and an anti-BUdR MAb. During exponential growth of the cells, the percentage of polymerase alpha-positive cells (the "polymerase alpha score") ranged from 72.0% to 77.1%, the Ki-67-positive cells (the "Ki-67 score") ranged from 43.4% to 59.4%, the PCNA/cyclin-positive cells from 30.9% to 41.4%, and the BUdR labeling index from 28.6% to 39.3%. For the in situ studies, tissue from 60 human brain tumors and from two normal human brains was investigated and the polymerase alpha scores and Ki-67 scores were compared. In normal brain tissue, no immunostaining was found by either method. In brain tumors, both the polymerase alpha scores and the Ki-67 scores correlated with the histological grade of malignancy. Polymerase alpha scores were generally higher than Ki-67 scores in the same specimen, especially in malignant brain tumors. These findings suggest that immunostaining of DNA polymerase alpha is a convenient and important new method by which to estimate the cellular proliferation rate of brain tumors. Polymerase alpha scores may be closer to the growth fraction of the individual tumor than the MAb Ki-67 or other scores.
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PMID:Immunohistochemical demonstration of DNA polymerase alpha in human brain-tumor cells. 196 2

Flow cytometry (FCM) is a useful method for clinical research of oncogene products since it can analyze proteins quantitatively which are located at cell surfaces or inside of cells. Oncogene products are now under study by FCM not only as tumor markers but also as functioning proteins in carcinogenesis. The examples of oncogene products analyzed by FCM are ras, myc, p53, myb and fos; those of cell-proliferation-related proteins are Ki-67, PCNA and DNA polymerase alpha. In some diseases the relationship between these proteins and disease classification, stage, pathophysiology, or prognosis have been clarified. Using dual color FCM of H-ras p21 and DNA, we analyzed the expression of H-ras p21 in human multiple myeloma and leukemias and found that H-ras p21 levels in multiple myeloma strongly correlated to the prognosis of patients (p = 0.03). When AML cells were stimulated by adding G-CSF, it was found that many cells proliferated but some were dying. The percentage of dying cells was small in one AML case whose myeloblasts showed increased expression of H-ras p21 by G-CSF stimulation. Together with other papers reviewed, it is conceivable that H-ras p21 expression is related to cell proliferation and inhibition of cell autolysis. Thus FCM is useful in the classification of the role of oncogene products in carcinogenesis in clinical cases.
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PMID:[Application of flow cytometry to the study of hematologic disorders: analysis of oncogene products]. 214 49

Several nuclear and surface proteins are expressed in varying amounts in the different phases of the cell cycle. For some of them the coding gene is not known and changes in their expression could simply be secondary to changes in the proliferative activity of the population. Other proteins are oncogene products, probably having a direct regulatory function in cell proliferation, differentiation and malignant transformation. Studying these proteins may both permit a better understanding of the mechanisms regulating proliferation and differentiation and provide kinetic parameters for describing the cell cycle. Based on antibodies against these proteins, bivariate flow cytometry (FCM) is able to quantitate their expression simultaneously with DNA distribution. This allows protein expression to be related precisely with each cell cycle phase in populations having different proliferative activity. Further advantages of bivariate FCM are that few cells are required for the analysis and the percentage of cells expressing the (onco) gene product can be determined. Several cellular proteins have been investigated with bivariate FCM, and the data are reviewed. Some proteins not coded by oncogenes (such as cyclin, the Ki-67 reactive antigen and DNA polymerase alpha) are expressed in cycling, but not in G0 cells and are of special interest for the kineticist, since they could identify cells which are able to initiate DNA synthesis, i.e. those representing the "growth fraction" of the population. Statin, on the contrary, is apparently expressed only in G0 cells. The expression of some proteins coded by oncogenes, such as p53 and the c-myc product is high in proliferating G1 cells and decreases with differentiation. The expression of the c-ras product is not strictly related to cell cycle phases and increases with differentiation. Technical improvements (allowing, for example, the monitoring of the changes in protein expression following the microinjection of a protein-blocking substance into the cells and the inclusion of phenotype markers into the analysis) will expand the role of bivariate FCM for these research works.
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PMID:Cell cycle-related proteins and flow cytometry. 214 99

Proliferative activity of 28 human brain tumors was estimated by simultaneous measurement of DNA polymerase alpha, Ki-67 and bromodeoxyuridine (BUdR) labeling indices on microscopic tissue preparations stained immunologically with monoclonal antibodies using a peroxidase technique. All the antigens were exclusively found in the nucleus. The labeling index of BUdR was lower than those of the other indicators. The values of the DNA polymerase alpha labeling index were almost the same as those of the Ki-67 labeling index. Simultaneous measurement of these parameters may provide more useful information on tumor cell growth kinetics than that of a single parameter.
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PMID:Measurement of labeling index of DNA polymerase alpha in human brain tumors. Comparative study with labeling indices of BUdR in vitro and Ki-67. 832 65

The versatility of non-radioactive cell-cycle analysis in detecting endogenous nuclear antigens of the proliferating cells was evaluated. Optimal conditions for immunostaining varied in fixation and pretreatment procedures among antigens, bromodeoxyuridine (BrdU), Ki-67 epitope, DNA polymerase alpha and PCNA. A significant correlation between BrdU labeling index (LI) was observed in each positive ratio (PR, positive/total neoplastic cells) for nuclear antigens in tumor-sections which had been labeled in vivo with BrdU. The best correlation was observed in Ki-67 PR (y = 1.26x + 2.5; y = Ki-67 PR; x = BrdU LI; r = 0.97). To determine its prognostic value, Ki-67 analysis was applied to the surgically resected lung tumors. Ki-67 PR were different according to the histologic types of the tumors: 47.8 +/- 3.4% in small cell carcinoma; 29.5 +/- 3.5% in squamous cell carcinoma; 28.3 +/- 4.7% in large cell carcinoma; 15.2 +/- 1.8% in adenocarcinoma and 0.1 +/- 0.1% in mature carcinoid tumor. When the mean value was used to divide each type to a higher or lower proliferative activity (15% Ki-67 PR for adenocarcinoma and 30% for squamous cell carcinoma), the group with the lower Ki-67 PR showed a significantly more favorable prognosis than that of a higher ratio. Ki-67 PR was not correlated with other pathologic factors such as size, lymph node metastasis or pleural involvement. Non-radioactive cell-cycle analysis was feasible and useful for detecting endogenous nuclear antigens even in the lung tumors, particularly when the analysis was coupled with histologic typing.
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PMID:Cell-cycle analysis detecting endogenous nuclear antigens: comparison with BrdU-in vivo labeling and an application to lung tumors. 834 8

Histochemical analyses with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies were done, and argyrophilic nucleolar organizer regions (Ag-NOR) were counted to estimate the proliferative potential of 200 brain tumors. The findings were compared with the bromodeoxyuridine labeling index (BrdU LI), or S-phase fraction. The proliferating cell indexes (PCI), determined by Ki-67 and anti-DNA polymerase alpha monoclonal antibodies were higher and Ag-NOR more numerous in medulloblastomas, glioblastomas, and metastatic carcinomas than in astrocytomas or meningiomas. The Ki-67 and DNA polymerase alpha PCI correlated with the BrdU LI (r = 0.87 and r = 0.84, respectively) and with each other (r = 0.94). The number of Ag-NOR correlated less strongly with these indexes in some tumors. These findings suggest that Ki-67 and anti-DNA polymerase alpha monoclonal antibodies may be useful for estimating the proliferative potential of individual tumors in routine clinical practice. The number of Ag-NOR, however, does not always reflect the growth potential of each tumor.
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PMID:Proliferative potential of brain tumors. Analyses with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies, bromodeoxyuridine labeling, and nuclear organizer region counts. 841 16

The cell proliferation represents one of the most relevant cellular functions. There are many approaches to assess the proliferative activity in tissues. Immunohistochemical methods offer a high sensitivity and specificity. They use monoclonal antibodies raised against specific antigens associated with the cell proliferation. Anti-BrdU immunohistochemistry detects bromodeoxyuridine (BrdU) which as an exogenous proliferation marker has been incorporated into the newly synthesized DNA of dividing cells. The best known endogenous proliferation markers are PCNA and Ki-67 that may be detected with specific commercially available antibodies. Here we describe our experience with an immunohistochemical detection of these proliferation markers. Anti-bromodeoxyuridine (BrdU) antibody binds BrdU that was exogenously introduced into the synthesizing DNA during the S-phase of the cell cycle. The precise timing and dosage of BrdU enable tissue kinetics studies. A long-time administration of BrdU may be used for labelling tissues with a low proliferative activity. BrdU incorporated into the cell nucleus is still a very stable antigen which gives a strong and reliable signal regardless the kind of fixation and further tissue processing. The proliferating cell nuclear antigen (PCNA) as an auxillary protein for DNA polymerase gamma is an evolutionarily conserved molecule that may be detected in human and animal frozen or paraffin-embedded tissues. In spite of the fact that anti-PCNA immunohistochemistry may weakly stain non-proliferating cells, PCNA is the most frequently detected proliferation marker. The staining intensity may be influenced by the kind of fixation and the length of microwave pretreatment. Ki-67 is another endogenous antigen detectable in proliferating cells. Its detection in paraffin-embedded sections requires also exposition to microwaves. Both Ki-67 and PCNA may be revealed in archival specimens that means these techniques do not require any prelabelling. Ki-67 labelling index (LI) correlates better with BrdU LI than PCNA LI as the Ki-67 antigen has a shorter half-life than PCNA.
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PMID:Immunohistochemical detection of proliferative cells. 868 26

Psoriasis is a chronic inflammatory disorder characterized by epidermal hyperproliferation. Although recent evidence suggests that T cell activation is a primary trigger for psoriasis lesions, there may be alterations in the keratinocyte growth regulatory pathways which induce epidermal hyperproliferation in psoriatic patients. To test this hypothesis, we investigated the proliferative activity of epidermal keratinocytes 48 h after tape stripping, one of the standard mechanical ways to stimulate the epidermis, in 20 psoriasis patients and in 18 controls. Epidermal cell kinetics were assessed with DNA flow cytometry, the mitotic index, bromodeoxyuridine incorporation, Ki-67 antigen expression and DNA polymerase alpha expression. The expression of TGF-alpha and EGF receptors, critical mediators of keratinocyte proliferation, were also investigated immunohistochemically. The results of multiparameter assays showed that the baseline proliferative activity in uninvolved skin was the same in psoriasis patients and normal controls. After tape stripping, although both psoriasis patients and the normal controls showed significant increases in epidermal cell proliferation, the values of all the parameters investigated were significantly greater in the psoriasis patients than in the normal controls. EGF receptors were overexpressed in basal and suprabasal keratinocytes after tape stripping in both the psoriasis patients and the normal controls. In contrast, overexpression of TGF-alpha was only observed in the patients with psoriasis, which may explain their increased proliferative response to trauma.
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PMID:Tape stripping induces marked epidermal proliferation and altered TGF-alpha expression in non-lesional psoriatic skin. 903 79

Liver regeneration is an essential component of the reparative process following liver injury and surgical resection. It can be assessed by different tissue-based tests such as liver weights, mitotic counts, DNA contents and synthesis rates, immunohistochemical staining of nuclear antigens, gene expressions and certain protein levels or various serum-based tests that largely consist of specific enzyme determinations or documentation of certain proliferation markers. Although the simplest tissue-based test of liver regeneration is measurement of liver weights, these determinations are influenced by the extent of deposition of various materials not directly related to regeneration, such as lipids, glycogen and blood volumes. Because mitosis constitutes a very short segment of the cell cycle, mitotic counts are infrequently observed by light microscopy. Thymidine and BrdU incorporation into DNA are the reference tools for studying DNA synthesis, but their use requires pre-injection with radioactive isotopes or nucleotides which render them impractical for human studies. Flow cytometry is an accurate and objective method of monitoring hepatic regenerative activity but requires sophisticated equipment that is not generally available in many laboratories. Immunohistochemical staining for nuclear antigens (Ki-67, proliferating cell nuclear antigen [PCNA], DNA polymerase alpha and nucleolar organizer region [NOR] proteins) are acceptable and commonly used methods of monitoring regenerative activity but are subject to inter- and intra-observer variability. Gene expression rates such as Histone-3 mRNA abundance are hampered by the relatively low rates of gene transcription and the need for recombinant DNA technology. Protein and enzyme levels in liver tissues, such as putrescine, ornithine decarboxylase and thymidine kinase, are not precise and are confounded by the nutritional status of the host. While PCNA protein levels measured by immunoblot hold promise as a simple, accurate and reproducible marker of liver regeneration, additional studies are required to determine if this is a valid marker of regenerative activity in various models of hepatic injury and in humans. Of the serum-based determinations: thymidine kinase, ornithine decarboxylase, fibronectin, alpha fetoprotein, and early pregnancy factor offer practical and non-invasive tools to monitor liver regeneration, but the sensitivity and specificity of these tests have yet to be determined. In conclusion, many tissue and serum-based methods have been employed in clinical and experimental studies to assess liver regeneration; however, a gold standard has yet to be identified. Because of the disadvantages inherent in each method, and until a new, more accurate marker is identified, clinicians and scientists should incorporate a minimum of two independent markers in studies of liver regeneration.
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PMID:Liver regeneration: methods for monitoring and their applications. 912 13


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