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 nucleolarorganizer 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.
12. Ofner D, Bier B, Heinrichs S, Berghorn M, Dunser M, Hagemann HA, Langer D, Bocker W, Schmid KW. Demonstration of silver-stained nucleolarorganizer region associated proteins (AgNORs) after wet autoclave pretreatment in breast carcinoma. Breast Cancer Res Treat 1996;39:165-176. 13. Piffko J, Bankfalvi A, Ofner D, Bryne M, Rasch D, Joos U, Bocker W, Schmid KW. Prognostic value of histobiological factors (malignancy grading and AgNOR content) assessed at the invasive tumour front of oral squamous cell carcinomas. Br J Cancer 1997;75:1543-6.
Argyrophilic proteins associated with nucleolarorganizer 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 . These proteins are revealed in cell nuclei along the whole cell cycle increasing in S- and G2-stages by 1.5—3 folds . Inverse relationship between AgNOR quantitative content and duration of the cell cycle , tumor doubling time [8,9] is shown.
This is to certify that this dissertation work titled “Argyrophilic NucleolarOrganizer 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.
Although the number of AgNORs is increased in malignancy,some workers considered it as not diagnostic due to overlap with benign proliferation..It seems that although the number of AgNORs per cell is not discriminatory enough on its own to determine malignancy, the addition of size or area measurements using image analysis gives improved diagnostic and prognostic specificity [11,28]. The present study was aimed to Evaluation of diagnostic value of the nucleolarorganizer region comparing reactive cells and transitional cell carcinomas.
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 Nucleolarorganizer 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.
The short arms of all the five human acrocentric chromosomes contain genomic region known as nucleolarorganizer regions (NORs). The NOR is the site of nucleolus formation and therefore play critical role in cell survival. It has two components: a tandem array of ribosomal DNA (rDNA) units and regions surrounding the rDNA tandem array, the rDNA flanking regions. In this work, I have explored both components of the NOR to unravel their genomic and functional features.
Abstract: Wild relatives of bread wheat are potential sources of valuable genetic materials for wheat improvement. Karyotype analysis plays an important role in the identification and designation of chromosomes in many plant species. In this study, the karyotype features and nucleolarorganizer regions (NORs) of 21 wheat genotypes representing diploid, tetraploid and hexaploid species and belonging to wild, cultivated and synthetic groups were investigated. Total chromosome length (TCL) values vary across the genotypes. The highest value (99.1 µm) was recorded in one of a synthetic hexaploid wheat (Doy1/ Ae. squarrosa (458)) with a mean chromosome length (MCL) of 5.67±0.59 µm, while the lowest value (39.48µm) was found in T. monococcum species with a mean chromosome length (MCL) of 4.06±0.51 µm. Cluster analysis based on chromosomal characteristics and karyotype asymmetry indices including symmetry index (S %), total form percentage (TF %), Romero-Zarco’s indices (A 1 and A 2 ) and
The nucleolarorganizer 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 “nucleolarorganizer” (McClintock 1934), which was later modified to “nucleolarorganizer region”. Although the location of the nucleolarorganizer 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.
Abstract: In this study, nucleolarorganizer regions of Chalcalburnus mossulensis were investigated. Analysis of karyotypes revealed that the diploid numbers of chromosomes was 2n=50. There were six pairs of metacentric, eight pairs of submetacentric, five pairs of subtelocentric and six pairs of acrocentric chromosomes in the karyotype. It was shown that C. mossulensis pos- sessed two pairs of nucleolarorganizer regions-bearing chromosomes. One nucleolarorganizer region was located terminally on the longer arm of a larger sized submetacentric chromosome, whereas the other nucleolarorganizer region was located terminally on the short arm of a me- dium sized submetacentric chromosome. There was no significant difference in chromosomal nucleolarorganizer region phenotypes and in number of nucleolarorganizer regions among lo- calities. Our results were compared with previous results of other researchers.
Abstract Since the argyrophilic nucleolarorganizer 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.
In the present study AgNOR staining was used along with as- sessment of cytomorphological features in FNA of thyroid lesions, 119 cases were studied & cytological diagnosis was given. Out of 119 cases stained with silvernitrate, 100 cases showed cellular foci for nucleolarorganizer regions (NORs) (Figures 1-6) and AgNOR score is given in Table 1. In remaining 19 cases AgNOR score was not given due to poor cellularity of the smears. Maximum num- bers of lesions were seen in the age group 21 to 30 years (39cas- es). Six (6) cases were noticed in males (5.04%) and hundred and thirteen (113) cases in females (94.96%) (Table 2). Benign lesions constituted 108 (90.75%) cases where as malignant lesions were 11 (9.24%). Nodular goiter was the commonest benign lesion (36.97%) and papillary carcinoma of thyroid was the commonest malignant lesion (5.88%) (Table 3). AgNOR score obtained in the present study was compared with the study conducted by other re- searchers and is presented in Table 4. AgNOR Score ranged from 1.66 to 1.80 for Benign lesions and from 3.07 to 3.15 for Malignant lesions.
The present study was to compare Argyrophilic NucleolarOrganizer 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.
is inhibited). In the presence of the combined fgf3/8 MOs, the dnSox3 was still able to elicit robust ectopic expression of these organizer genes (Fig. 3E–F). However, that fact that treatment with MOs targeting fgf3 and fgf8 did not affect the response to dnSox3 could be because MOs generally only cause knock down rather than complete loss of target proteins. Alternatively, other Fgfs (such as Fgf24 or Fgf17, which are expressed even earlier than Fgf3 and Fgf8 in mesoderm and organizer , ), may also play a role. Therefore we used the FGFR1 inhibitor, SU5402, as a more effective and broader inhibitor of Fgf signaling to address this question. Inhibition of Fgf signaling using SU5402 completely abolished both the endogenous and the ectopic induction of these gsc and chd expression by dnSox3 (Fig. 3G–N). In order to confirm that this effect was due to inhibition of Fgf signaling, we repeated this experiment using the alternative, intracellular, Fgf signaling Figure 1. SoxB1 factors acts as transcriptional repressors to inhibit the expression of fgf3 and fgf8. At 4.5 hpf, the expression of fgf3 and fgf8 is restricted in the dorsal shield region of un-injected embryos (A–B). Injection of sox3, sox19a or sox19b RNA at the 1–2 cell stage caused complete loss of expression of both fgf3 and fgf8 at 4.5 hpf (C–H). A Sox3HMG-EnR (I,J) but not a Sox3HMG-VP16 (K,L) fusion mimicked the function of wild-type Sox3 to inhibit fgf3 and fgf8 expression. Ectopic expression of fgf3 and fgf8 was induced by the dnSox3 construct injected at the 1–2 cell stage and analysed at 4.5 hpf (M,N) or later at 30% epiboly (5.5 hpf) (O,P). All images are lateral views with dorsal to the right (where this can be determined). The proportion of embryos exhibiting these phenotypes is shown at the bottom right of each panel. Scale bar in panel A represents approximately 100 mm.
How much of the hypostomal tissue is involved in the head organizer? Expression of genes, as described in the next section, would indicate that it may be a small part of the hypostome at it’s apex. An experiment by Technau et al.,2000) provides evidence consistent with this viewpoint. When several Hydra are dissoci- ated into a suspension of cells that is subsequently centrifuged into a pellet and then placed in Hydra medium, it undergoes the following developmental process. The epithelial cells of the pel- let, or aggregate, sort out into a spherical shell consisting of two concentric layers, similar to the organization of these two layers in an intact Hydra (Gierer et al., 1972). The outer layer is composed of the ectodermal epithelial cells and the inner layer of the endo- dermal epithelial cells. Subsequently, one or more head organiz- ers form, which organize the tissue of the aggregate into one or more animals consisting of head and body column. Technau et al., 2000) added small clusters [10-180 cells] of cells labeled with FITC from regenerating heads to suspensions of dissociated cells and formed aggregates. 50% of the clusters were subsequently found in developing heads. In contrast, clusters formed from cells of the body column were rarely [2-10%] found in developing heads. Hence, a relatively small cluster of cells committed to organizer formation is sufficient to set up a head organizer.
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The nucleolus is susceptible to cellular stress, causing rapid degradation of nucleolar proteins . To investi- gate whether the glutamate incubation induces nucleolar stress, the levels of key nucleolar proteins were exam- ined. Western blotting for FBL, UBF and TIP5 revealed a reduction in intensity of the bands for all three pro- teins and analysis showed a significant decrease in TIP5, FBL and UBF protein levels in glutamate-treated cells compared to controls (Fig. 3b). The rapid decrease in these nucleolar proteins implies that the glutamate treat- ment directly affects the nucleolus causing its reorgani- sation. Indeed, different cellular stresses feed into the nucleolus, leading to the regulation of the energy con- suming process of ribosome biogenesis through the in- hibition of rDNA transcription allowing for the regulation of energy expenditure during stress. To fur- ther confirm the presence of nucleolar stress, we mea- sured the levels of 45S pre-rRNA and found that the glutamate treatment led to a decrease (14%) in 45S pre-rRNA, indicative of a reduction in rDNA transcrip- tion (Fig. 3c). These findings revealed that the stress in- duced by glutamate impacts on the nucleolus, causing nucleolar stress, which ultimately results in cell death .