argyrophilic nucleolar organizer region

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Evaluation of diagnostic accuracy of PAP (papanicolaou) and AgNOR (argyrophilic nucleolar organizer regions) staining in exfoliative cytology of oral mucosa in smokers and non smokers

Evaluation of diagnostic accuracy of PAP (papanicolaou) and AgNOR (argyrophilic nucleolar organizer regions) staining in exfoliative cytology of oral mucosa in smokers and non smokers

It is a complementary diagnostic method which presents several advantages such as rapid and easy execution, low cost, diagnostic safety, efficacy and non-invasiveness, and can be repeated several times (Fontes, 2007; Paiva, 2004 and Remmerbach, 2003 and Sethi, 2003). Papanicolaou(PAP) staining is used as a routine method for the analysis of cytological aspects and permits the identification of basic inflammatory, dysplastic or malignant alterations. Ever since PAP described exfoliative cytology technique, which is non- painful, non-invasive procedure, it has become a valuable tool for cancer screening (Ahmed, 2009). Argyrophilic Nucleolar organizer regions (AgNORs) are located in the cell nucleoli during interphase. They are loops of DNA in which ribosomal RNA is encoded. Nucleolar organiser regions (NORs) are defined as nucleolar components containing a set of argyrophilic proteins, which are selectively stained by silver methods. After silver-staining, the NORs can be easily identified as black dots exclusively localised throughout the nucleolar area, and are called "AgNORs". The NORs' argyrophilia is due to a group of nucleolar proteins, which have a high affinity for silver (AgNOR proteins) (Trere, 2002). NORs are proteins that are associated with the fibrillar centers and dense fibrils of the cell nucleus during interphase and are responsible for the replication of RNA. Thus, the larger the number of NORs, the higher the replication rate of ribosomes and cells. This technique has therefore been used for the quantification of cell proliferation in different tissues and lesions (Cancado, 2001). In the present study, we examined exfoliative cytology from the lateral border of the tongue which is a site associated with a high incidence of oral cancer, in both smokers and nonsmokers. The objective of this study was to determine the influence of smoking habit on oral mucosa with the help of proliferative markers and to determine whether a correlation exists between the results obtained by Papanicolaou staining and by histochemical AgNOR quantification to analyze the accuracy of AgNOR over wide usage of PAP for cytopathology.
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Argyrophilic nucleolar organizer regions (AgNORs) as a proliferative marker inbenign, premalignant and malignant prostatic lesions

Argyrophilic nucleolar organizer regions (AgNORs) as a proliferative marker inbenign, premalignant and malignant prostatic lesions

This is to certify that this dissertation work titled “Argyrophilic Nucleolar Organizer Regions (AgNORs) as A Proliferative Marker In Benign, Premalignant and Malignant Prostatic Lesions” of the candidate Dr. KANIMOZHI.Twith registration Number 201513252 for the award of M.D in the branch of Pathology. I personally verified the urkund.com website for the purpose of plagiarism Check. I found that the uploaded thesis file contains from introduction to conclusion pages and result shows 1% (one) percentage of plagiarism in the dissertation.
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Quantification of Argyrophilic Nucleolar Organizer Regions

Quantification of Argyrophilic Nucleolar Organizer Regions

Context: Although most oral cancers probably arise in clinically normal mucosa, some are preceded by a precancerous lesion, which indicates an increased risk of cancer development at a particular site. The degree of epithelial dysplasia is a useful guide in the diagnosis and management of such lesions. Many recent reports have suggested that the number of nucleolar organizer regions (NORs) per nucleus is related to cellular proliferation and differentiation. The NORs can be identified indirectly by means of argyrophilia of their associated proteins. Aim: To evaluate the argyrophilic NORs (AgNORs) in different histopathological grades of oral epithelial dysplasia.
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Prognostic Validity of AgNOR in Pleomorphic Adenoma

Prognostic Validity of AgNOR in Pleomorphic Adenoma

Abstract Since the argyrophilic nucleolar organizer region (AgNOR) technique has successfully distinguished various grades of malignancies and enabled prognostic assessment, this paper traces its prognostic validity in predicting the behavior of pleomorphic adenoma (PA). Ten cases of recurrent PAs were compared, on the one hand, where AgNOR score of area fraction was measured before and after recurrence. The same findings were contrasted to ten cases of normal glandular mucosa. Diagnosing both pleomorphic adenomas was based on clinical and histological records of the archival submitted cases. The data were statistically analyzed by t-test, ANOVA, Tukey and Pearson’s tests. The study concludes that AgNOR score lack the prognostic validity on testing PA, in terms of distinguishing and or predicting recurrence.
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A comparative study of AgNOR with pcna immunohistochemical staining in oral squamous cell carcinoma

A comparative study of AgNOR with pcna immunohistochemical staining in oral squamous cell carcinoma

The present study was to compare Argyrophilic Nucleolar Organizer Regions (AgNORs) with Proliferating Cell Nuclear Antigen (PCNA) expression in Oral squamous cell carcinoma (OSCC) and to assess the proliferating activity in OSCC, also to assess the reliability Previously confirmed 30 cases of oral squamous cell carcinomas were taken for the study. Histological sections were prepared from paraffin embedded blocks and processed for AgNOR stain and PCNA stain according to super sensitive polymer HRP method. The statistical evaluation by ANOVA test helped us to compare and correlate between the two methods.
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Identification of Pax2 regulated genes by expression profiling of the mid hindbrain organizer region

Identification of Pax2 regulated genes by expression profiling of the mid hindbrain organizer region

Pax2 plays a key role in the formation of the isthmic organizer (IsO) that controls midbrain and cerebellum development (Favor et al., 1996; Bouchard et al., 2000; Ye et al., 2001). Despite the importance of Pax2 for mid-hindbrain patterning, relatively little is known about target genes that are activated by Pax2 at the onset of mid-hindbrain development. We have previously shown that Pax2 is essential for initiating expression of the closely related Pax5 and Pax8 genes, indicating that the inactivation of Pax2 is equivalent to mutation of all three Pax2/5/8 family members at the mid-hindbrain boundary (Pfeffer et al., 1998; Pfeffer et al., 2000; Ye et al., 2001). Pax2 is furthermore necessary and sufficient for inducing the expression of the IsO signal Fgf8 (Ye et al., 2001). Here, we have used gene expression profiling of mid-hindbrain cells from wild-type and Pax2 –/– embryos as a more systematic strategy for identifying Pax2-regulated genes. This approach relies on transgenic GFP labeling and FACS sorting of Pax2- expressing cells followed by linear RNA amplification, probe preparation and cDNA microarray screening. In this way, we identified five genes, En2, Brn1, Sef, Tapp1 and Ncrms, which are expressed in the developing mid-hindbrain region under the control of Pax2. The molecular nature of these new target genes implicates Pax2 in the control of intracellular signaling and the establishment of transcription factor networks in the mid- hindbrain region.
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Characterization of the human nucleolar organizer regions : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Genetics at Massey University, Albany, New Zealand

Characterization of the human nucleolar organizer regions : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Genetics at Massey University, Albany, New Zealand

sequences of the flanking regions are highly conserved among the acrocentric chromosomes suggesting that they frequently exchange sequences. The proximal region similar to the pericentromeric regions is highly segmentally duplicated. On the other side, the distal region is merely segmentally duplicated but has two unique features a large inverted repeat region (~227 kb) and a long stretch of CER satellite repeats, potential binding site of a protein of unknown function. These parts of the genome are thought to be heterochromatic, however I employed a gene prediction pipeline that provide evidence for coding potential in both the flanking regions. Finally, it has been reported that the proximal junction point may be variable therefore, I designed a novel bioinformatics mapping technique, which suggests there are at least two distinct proximal junction points. Overall, this work demonstrates that the rDNA flanking regions are not merely heterochromatic wastelands but instead are highly complex and have its own genomic characteristics.
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The Role of Net1 Phosphorylation in Regulating CDC14 Release During Mitotic Exit

The Role of Net1 Phosphorylation in Regulating CDC14 Release During Mitotic Exit

The RENT complex is composed of three identified components: Net1 a nucleolar protein responsible for maintaining nucleolar integrity and regulating the activation and release of Cdc14 t[r]

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Autoantibody to RNA polymerase I in scleroderma sera

Autoantibody to RNA polymerase I in scleroderma sera

Autoantibodies to components of the nucleolus are a unique serological feature of patients with scleroderma. There are autoantibodies of several specificities; one type produces a speckled pattern of nucleolar staining in immunofluorescence. In actinomycin D and 5,6- dichloro-beta-D-ribofuranosylbenzimidazole-treated Vero cells, staining was restricted to the fibrillar and not the granular regions. By double immunofluorescence, specific rabbit anti-RNA polymerase I antibodies stained the same fibrillar structures in drug-segregated nucleoli as scleroderma sera. Scleroderma sera immunoprecipitated 13 polypeptides from [35S]methionine-labeled HeLa cell extract with molecular weights ranging from 210,000 to 14,000. Similar polypeptides were precipitated by rabbit anti-RNA polymerase I antibodies, and their common identities were confirmed in immunoabsorption experiments.
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Effects of a highly basic region of human immunodeficiency virus Tat protein on nucleolar localization.

Effects of a highly basic region of human immunodeficiency virus Tat protein on nucleolar localization.

4 0022-538X/90/041803-05$02.00/0 Copyright C 1990, American Society for Microbiology NOTES Effects of a Highly Basic Region of Human Immunodeficiency Virus Tat Protein on Nucleolar Local[r]

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Characterization of the human nucleolar organizer regions : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Genetics at Massey University, Albany, New Zealand

Characterization of the human nucleolar organizer regions : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Genetics at Massey University, Albany, New Zealand

The nucleolar organizer region (NOR) is the chromosomal location in eukaryotes around which the nucleolus is formed. The nucleolus is a sub-nuclear, non-membranous structure which is defined by a heterochromatic shell (Mosgoeller 2004). It is the site of ribosome biogenesis and therefore essential for the cell survival. In the late 18 th century Fontana described an oval shaped body in eel saliva cells (adapted from Mosgoeller 2004) that was later (in 1836) termed the nucleolus by Gabriel Gustav (as cited in Mosgoeller 2004). Emil Heitz was the first to report the chromosomal context of the nucleolus using Zea mays (as cited in Mosgoeller 2004). His work was further elaborated on by Barbara McClintock and she termed the genomic region around which the nucleolus is formed as the “nucleolar organizer” (McClintock 1934), which was later modified to “nucleolar organizer region”. Although the location of the nucleolar organizer region was demarcated on the genome, the underlying sequence and function was still not known. In late 1950s densely stained particles were observed in the nucleoli that were speculated to be ribosomes (as cited in Birnstiel and Hyde 1963). In the early 1960s Edström et al. (1960) and Birnstiel et al. (1963) demonstrated that the nucleolar RNA composition is similar to that of cytoplasmic RNA, and differs to that of the nucleus. The discovery that the sizes of the RNA molecules in the nucleolus are the same as cytoplasmic RNA lead to the idea that ribosomes are stored in the nucleolus in addition to their known abundant presence in the cytoplasm (Birnstiel et al. 1963). However, it was not clear if ribosomes are synthesized in the nucleolus or are just stored there (McConkey and Hopkins 1964). Ritossa and Spiegelman (1965) had first reported that multiple copies of the ribosomal DNA (rDNA) units were arranged in clusters in the nucleolus of Drosophila melanogaster using an RNA-DNA hybridization technique, thus demonstrating that the NOR contains rDNA. This finding also established that ribosomes are not stored but are synthesized in the nucleolus. The presence of rDNA in the nucleoli of other organisms (Phillips et al. 1971) verified that the rDNA is a universal building block of the NORs.
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Evolution of cis-regulatory modules for the head organizer gene goosecoid in chordates: comparisons between Branchiostoma and Xenopus

Evolution of cis-regulatory modules for the head organizer gene goosecoid in chordates: comparisons between Branchiostoma and Xenopus

In vertebrate embryogenesis, the head region is in- duced during the gastrula stage by the head organizer, which is the anterior part of the gastrula organizer (the Spemann-Mangold organizer in amphibians, the shield in teleosts, and the mid-gastrula organizer in mice). It should be noted that, in mouse embryos, anterior vis- ceral endoderm is also involved in the anterior pattern- ing despite the absence of axis inducing activity [9]. To understand head evolution in chordates, we focused on molecular mechanisms underlying head organizer for- mation, following gastrula organizer formation. In Xen- opus and zebrafish, the gastrula organizer is formed in the late blastula stage by maternal canonical Wnt signal- ing from the dorsal region and Nodal signaling from the dorsovegetal region, which induce so-called organizer genes encoding transcription factors such as Otx2, Lim1, and Gsc, as well as Bmp antagonists such as Noggin, Chrd, and Cerberus involved in dorso-ventral (DV) pat- terning [10–13]. During gastrulation, the organizer is gradually divided into head and trunk organizers, which promote antero-posterior (AP) patterning of neuroecto- derm [14, 15]. The head organizer induces forebrain and midbrain formation and also determines the anterior midline [16]. Head and trunk organizer regions develop into the prechordal plate and the notochord, respect- ively. The prechordal plate is a vertebrate-specific tissue that escapes from convergent extension movements oc- curring in notochordal cells.
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Rad53 homologue forkhead-associated kinase A (FhkA) and Ca2+-binding protein 4a (CBP4a) are nucleolar proteins that differentially redistribute during mitosis in Dictyostelium

Rad53 homologue forkhead-associated kinase A (FhkA) and Ca2+-binding protein 4a (CBP4a) are nucleolar proteins that differentially redistribute during mitosis in Dictyostelium

It is possible that anti-CBP4a may also detect CBP4b since the two evolved on a separate branch from the major- ity of the other CBPs in Dictyostelium. Previous data is in- sufficient to determine any potential differences in function or localization between them [39]. Although the region in CBP4b most resembling the antigen site in CBP4a differs only by one residue (CBP4b contains A instead of G at pos- ition 26) analysis of mRNA expression revealed that in vegetative cells CBP4a mRNA is approximately 8.3-times more abundant that that of CBP4b suggesting that any de- tection of CBP4b by anti-CBP4a would be minimal [52,53]. AM-D treatment results in nucleolar dissolution accom- panied by the disappearance of nucleolar proteins in Dictyostelium which is consistent with observations by others [20,22,24]. CBP4a also disappeared from the nucle- olus after AM-D treatment. In contrast, FhkA protruded from the nucleus to eventually pinch off as cytoplasmic circles. Given the relationship between microtubules and the nucleolar protrusion that occurs during the aggrega- tion stage of Dictyostelium development we decided to in- vestigate whether microtubules also functioned during the AM-D-induced protrusion observed here. However the AM-D-induced protrusions were still observed despite the lack of microtubules suggesting that this mechanism of nucleolar protrusion is fundamentally different than that observed during aggregation that occurs during normal multicellular development. Interestingly, the same AM- D-induced phenomenon of nuclear protrusion was also observed for nucleolar Snf12 but not for NumA1 or eif6 [22,24,25]. In all cases, the location of these protru- sions was on the side of the nucleolus farthest from the centrosome which was the same as for Snf12 [25].
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The avian organizer

The avian organizer

Grafting of Hensen’s node below competent ectoderm induces a neural plate, elevated neural folds, or even a closed neural tube (for an example see Fig. 5). This remarkable inductive potential of the node was first demonstrated by Waddington, and served to recog- nize the node as the equivalent of the dorsal blastopore lip in amphibia, the Spemann-Mangold organizer (Waddington, 1932). It has by now been investigated to a great detail both on a functional and a molecular level (e.g. Dias and Schoenwolf, 1990; Storey et al., 1992; Lemaire et al., 1997; Pera et al., 1999). Molecular markers demonstrate readily that node-induced neural axes are regionally structured into fore-, mid-, hindbrain and spinal cord quality (Fig. 5). It is typical for such inductions that the basal membrane at the grafting site does not become interrupted, and therefore no mesoderm is formed. The potential for the induction of anterior neuroectoderm is restricted to the node at the extended streak stages, i.e. when it contains cells fated to the definitive endoderm or the mesendoderm. An efficient contribution of a node graft to the host endoderm normally is accompanied by efficient neural induction (Dias and Schoenwolf, 1990). The development of an endodermal layer appears to be essential for the formation of a neural plate (Pera et al., 1999). The inductive potentials of different primitive streak segments are significantly different (Fig. 6). After transplantation to the anterior extraembryonic region (Fig. 5A), post-nodal grafts still induce neur- oectoderm, but fail to induce anterior markers (Knoetgen et al., unpublished). The potential of even further posterior streak grafts is restricted to the induction of secondary primitive streaks. These are more likely to express also anterior streak markers, i.e. the classical organizer markers (Chordin, GSC, HNF3 β ; Lemaire et al., 1997), if they contain cells from the anterior middle portion of the streak (Fig. 6). In contrast, secondary streaks induced by fragments from the middle of the streak do not express these genes and are restricted to more general streak markers, in particular Brachyury (Ch-T; Gallera and Nicolet, 1969; Lemaire et al., 1997).
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Expansion and contraction of the nucleolus organizer region of Neurospora: changes originate in both proximal and distal segments.

Expansion and contraction of the nucleolus organizer region of Neurospora: changes originate in both proximal and distal segments.

Meiotic recombination between rDNA located on homologous chromosomes has not been observed in Neurospora (RUSSELL, PETERSEN and WAGNER 1988), but it seemed possible [r]

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Evidence for Nucleolus Organizer Regions as the Units of Regulation in Nucleolar Dominance in Arabidopsis thaliana Interecotype Hybrids

Evidence for Nucleolus Organizer Regions as the Units of Regulation in Nucleolar Dominance in Arabidopsis thaliana Interecotype Hybrids

marker ANL2 in combination with every other marker tems. Our demonstration that uniparental rRNA gene to find genetic interactions that contribute to nucleolar expression occurs in fertile, diploid hybrids of geo- dominance. A significant epistatic interaction was found graphically isolated ecotypes of A. thaliana provides a between the NOR QTL and several adjacent markers new system that circumvents these problems. In hybrids located on chromosome 3 (Figure 5A). This interaction of the A. thaliana ecotypes Cvi and Ler, nucleolar domi- accounts for as much as 10% of the variation seen in nance can be observed in the F
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Chromosome rearrangements that involve the nucleolus organizer region in Neurospora.

Chromosome rearrangements that involve the nucleolus organizer region in Neurospora.

Loss typi- cally involves detachment of the translocated segment from the NOR (Table 2). The rate at which duplicated segments are deleted differs dramatically for the diffe[r]

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STUDY OF KARYOTYPE AND NUCLEOLAR ORGANIZER REGIONS (NORS)IN WILD, SYNTHETIC AND CULTIVATED WHEATS

STUDY OF KARYOTYPE AND NUCLEOLAR ORGANIZER REGIONS (NORS)IN WILD, SYNTHETIC AND CULTIVATED WHEATS

Nucleolus organizer regions are a very important landmark for recognition and identification of chromosomes in plant species. Ag-NOR banding has been vastly used to analyze nucleolus activity in diploid and polyploidy plants, interspecific hybrids and chromosome addition lines (Fukui and Nakayama, 1997). The method of staining nucleolus organizing regions (NORs) of chromosomes with silver nitrate (the silver- staining procedure) is also suitable for estimation of rDNA transcription rate in plants. For example, this approach has been used for the estimation of NOR activity in onion leaves and wheat roots treated with plant growth (Fatkhutdinova et al., 2002). In hexaploid wheat, three chromosome pairs (IB, 6B, and 5D) are known to possess nucleolar activity; however, usually only 1B and 6B show a secondary constriction (Cermeno et al., 1984). Each diploid Triticeae species has either one or two chromosome pairs with NORs, which are present in different locations on the chromosomes of homoelogous groups 1, 5 and 6. These major NORs contain from hundreds to thousands of 18S-26S rRNA repeated gene units and their expression can be visualized by their nucleolus organizing activity and Ag-NOR banding (Badaeva et al., 1996).
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Interrelation of Argyrophilic Proteins ofNucleolar Organizer Regions andKi-67 withClinical and Morphological Parameters andSurvival in Patients with Non-small CellLung Cancer

Interrelation of Argyrophilic Proteins of Nucleolar Organizer Regions and Ki-67 with Clinical and Morphological Parameters and Survival in Patients with Non-small Cell Lung Cancer

Argyrophilic proteins associated with nucleolar organizer regions (AgNOR) are the markers of the cell cycle rate. Up to 75% of AgNOR staining is accounted for by two main argyrophilic proteins C23 (nucleolin) and B23 (nucleophosmin), which play a very important role in ribosomal RNA synthesis [5]. These proteins are revealed in cell nuclei along the whole cell cycle increasing in S- and G2-stages by 1.5—3 folds [6]. Inverse relationship between AgNOR quantitative content and duration of the cell cycle [7], tumor doubling time [8,9] is shown.

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Utility of Histochemical and Immunohistochemical Profile in Grading of Squamous Cell Carcinoma of the Oral Cavity

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NORs are the indicators of transcriptional activity of DNA and can be visualised by staining with silver nitrate under prescribed guidelines; the structures thus demonstrated are termed AgNORs. AgNORs appear as intra-nuclear, black to brownish black dots, against a pale yellow to golden yellow background. The above findings suggest that as the metabolic and morphological characters of malignant cells progressively get altered, the chromosomal and the AgNOR distribution gets disorganised culminating in the formation of small, multiple and dispersed nucleoli which reflects increase in the number of AgNORs with increasing malignancy grade and that impaired cell cycle and defective nucleolar association are accountable for increased AgNOR counts in progressing grades of OSCC. The protein synthesis is abnormally elevated in malignant cells and this is responsible for increased AgNOR counts.
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