Silver-stained Nucleolar Organizer Regions Research Articles

A Comparative Study of Morphometric Analysis of Nucleolar Organizer Regions in Oral Leukoplakia and Oral Squamous Cell Carcinoma and Significance of AgNOR as a Diagnostic Tool.

Background Silver stainable nucleolar organizer regions (AgNORs) have proven to exhibit utmost importance due to their higher occurrence in the nucleus especially in malignant cells than in normal. Thus, they assist in the examination of nucleolar structures and variations in nucleolar activity. Aim Quantitative and qualitative analysis in relation to the number and area of AgNOR in tissue sections of the normal oral mucosa (NOM), oral leukoplakia (OL), and oral squamous cell carcinoma (OSCC) was the main aim of the study. Materials & method A total of 50 cases comprising 20 OL with dysplasia, 20 OSCC cases, and 10 samples of normal oral mucosa were taken. Silver nitrate (Sol A) & gelatin (Sol B) solutions were freshly prepared for staining the lesional slides. Results The mean value of nuclear profile area (A Nuc) was comparatively higher in oral leukoplakia i.e. 41.97 and in oral squamous cell carcinoma i.e. 62.36 in comparison to the control group where it was 36.19. The mean value of a single AgNOR profile area per nucleus (A NOR) was found to be comparatively lower in both study groups i.e. oral leukoplakia (2.76) and oral squamous cell carcinoma (1.61) in comparison to the control group (3.45) . The mean value of total AgNOR profile area per nucleus (TA NOR) and the number of profiles of AgNORs per nucleus (n NOR) were found higher in both study groups (oral leukoplakia and oral squamous cell carcinoma) as compared to normal oral mucosa of the control group. However, the findings of all four parameters of morphometric analysis were found to be significantly associated with disorder of oral mucosa i.e. cases of oral leukoplakia and oral squamous cell carcinoma (P value<0.01). Conclusion It can thus be suggested that the mean AgNOR count displayed a higher value in OSCC. Hence, the number of AgNORs in nuclei increases as epithelial cells undergo malignant transformation which is designated that mean AgNOR count may contribute to establishing the prognosis of a lesion.

Efecto del extracto alcohólico de Tarantula cubensis y el destilado de Nerium oleander sobre los marcadores de proliferación celular en la carcinogénesis de colon

Colorectal Cancer (CRC) is defined as colon and rectum cancer and is among the major causes of mortality in developed Countries. Tarantula cubensis alcoholic extract (TCAE) and Nerium oleander distillate (NOD) are reported to have anticancer and antioxidative activity. In this study, it was aimed to research the impact on cell proliferation markers of TCAE and NOD given simultaneously in experimental colon cancer. A total of 24 rats, 6 in each group, were used in the study. Cancer Control (CC): Azoxymethane was administered at the beginning of the experiment at a dose of 15 miligrams (mg)· kilograms-1 (kg), (Subcutaneous, SC) twice, with an interval of a week (wk), to induce cancer. CC+TCAE: the dosage of Azoxymethane administered was 15 mg·kg-1 (SC) twice a wk at the beginning of the experiment, while in the case of TCAE, it was 0.2 mL·kg-1 (SC) once a wk for 18 wk from the beginning of the experiment. Fifteen mg·kg-1 (SC) of Azoxymethane was administered twice at one-wk intervals at the beginning of the experiment to the CC+NOD group, and NO distillate (NOD) was given with water throughout the experiment. Afterwards, animals were euthanized under appropriate conditions, paraffin blocks formed from colon tissues, histochemical AgNOR (Silver-stained nucleolar organizer regions), and immunohistochemical PCNA (proliferating cell nuclear antigen) stainings were performed. In the study, immunohistochemically, PCNA scores and AgNOR count per nucleus (AgNCI) were significantly decreased in C-TCAE and C-NOD groups (P&lt;0.001). AgNOR Area index (AgNAI) (P&lt;0.01), Core Area Index (CAI) (P&lt;0.05), and AgNOR Area index/Core Area Index (AgNAI/CAI) (P&lt;0.01) scores were significantly decreased in the C-TCAE group. As a result, it was concluded that both TCAE and NOD are effective as chemopreventive drugs and that TCAE presents a more pronounced antiproliferative effect than NOD.

Cytogenetic and Molecular Characterization of Oligosarcus pintoi (Characidae): A New Record of Supernumerary Chromosome in this Species.

The genus Oligosarcus currently comprises 24 valid species distributed in the major river basins of South America. In this group, nine species were cytogenetically investigated, and found to share a diploid number of 50 chromosomes. Despite the conservation of the diploid number, variations in the karyotypic formula, number and position of the nucleolar organizer regions, and longitudinal bands have been described between both species and populations. In this study, we present cytogenetic and molecular data from Oligosarcus pintoi specimens from the Keller River, a tributary of the Ivaí River (Upper Paraná basin), using DNA barcoding and cytogenetic markers (C-band, silver-stained nucleolar organizer regions, and fluorescence in situ hybridization of 18S and 5S rDNA). The genetic inferences reached after analyzing the cytochrome c oxidade subunit 1 gene allowed us to confirm the identity of the individuals with 2n = 50 chromosomes. However, one specimen contained a medium subtelocentric supernumerary chromosome (2n = 51). This is the second record of additional chromosomes in O. pintoi, thereby confirming the existence of a supernumerary chromosome in allopatric populations of this species, a fact that demonstrates an evolutionary path that is divergent from other populations and/or species of Oligosarcus analyzed so far, contributing to the karyotypic diversification of the group.

Chromosomal Instability and Origin of B Chromosomes in the Amazonian Glass Tetra Moenkhausia oligolepis (Günther, 1864) (Characiformes, Characidae)

B chromosomes occur in different species of the small characid fishes of the genus Moenkhausia. These supernumerary elements, that do not recombine with chromosomes of the standard A complement and follow their own evolutionary mechanism vary in number, morphology, and distribution. Here, we show karyotypic data of individuals of 2 populations of Moenkhausia oligolepis of the Brazilian Amazon (Pedro Correia and Taboquinha streams, Tocantins river basin), both with a diploid number of 50 chromosomes and karyotypic formula of 10m + 32sm + 8a. In addition to the normal complement, we also observed the occurrence of B chromosomes in the 2 populations with intra- and interindividual variation ranging from 0 to 10 Bs, independent of sex. The C-banding pattern evidenced heterochromatic blocks located mainly in the pericentromeric region of the chromosomes, while the B chromosomes appeared euchromatic. Silver-stained nucleolus organizer regions were identified in multiples sites, and some of these blocks were positive when stained with chromomycin A_3. The karyotype analysis and the application of whole-chromosome painting in populations of M. oligolepis reinforce the conservation of the basal diploid number for the genus, as well as the evolutionary tendency in these fishes to carry B chromosomes. Both populations turned out to be in different stages of stability and expansion of their B chromosomes. We further suggest that the origin of these chromosomes is due to the formation of isochromosomes. Here, we identified a pair of complement A chromosomes involved in this process.

Unusual chromosome numbers and polyploidy in invasive fire ant populations.

Fire ants (Solenopsis invicta Buren in J Ga Entomol Soc 7:1-26, 1972), an invasive alien ant species, first spread from South America to the United States in the 1930s, the southern part of the United States by the end of the twentieth century, Oceania, Taiwan, and China in the twenty-first century, and finally to Japan and South Korea in 2017. As these ants have significant negative economic, human health, and environmental impacts, the purpose of this research was to accumulate cytogenetic information regarding fire ants and provide basic data for developing management strategies for their control. Fire ants were collected from invasive populations from Taiwan, Florida (USA), and Buenos Aires (Argentina), and a native population from Puerto Iguazu (Argentina), their point of origination, and analyzed with regard to chromosome number, morphology, and polyploidy, silver-stained nucleolar organizer regions (Ag-NORs), and 18S rDNA and telomere fluorescence in situ hybridization (FISH). The results showed that (1) fire ants from invaded populations differed in chromosome morphology compared to those from native populations; (2) the Florida and Taiwanese fire ant populations evinced greater variability in chromosome numbers and polyploidy variations; (3) the Taiwanese population exhibited significantly increased Ag-NOR signals in interphase cells, with signal number significantly positively correlating with distance from native populations; and (4) substantial diversity of signals was also apparent following 18S rDNA and telomere FISH analyses. Variation in these characteristics were hypothesized to be due to (1) the effect of hybridizations and interbreeding between closely related species or genetically distant populations, and (2) the potential effect of large amounts of insecticides sprayed for pest control.

Effect of Pethidine Hydrochloride on the Development of Neural Tube: A Genetic Analysis Study in a Chick Embryo Model

Neural tube defects are among the most frequent congenital abnormalities of the central nervous system. Progression of neural tube deficits is affected by hereditary predilection and environmental determinants. Pethidine (meperidine) is a fast and powerful opioid analgesic in U.S. Food and Drug Administration category C. There are reports about developmental anomalies due to this medication. The aim of this study was to investigate the effects of different doses of pethidine hydrochloride on neural tube development in a chick embryo model resembling the first month of vertebral growth in mammals. Seventy-five specific pathogen-free eggs were incubated for 28 hours and divided into 5 groups (including the control group), each consisting of 15 eggs. Pethidine hydrochloride was administered sub-blastodermically with a Hamilton microinjector in 4 different doses. Incubation was continued until the end of the 48th hour. Subsequently, all eggs were opened, and embryos were cut from the embryonic membranes and evaluated morphologically, genetically, and histopathologically. Crown-rump length, somite numbers, and silver-stained nucleolar organizer region (AgNOR) number averages, and total AgNOR/nuclear area ratios decreased in a dose-dependent manner. Examination of neural tube closure revealed statistically significant differences in all experimental groups (P<0.05). Messenger RNA levels of the BRE gene were decreased in pethidine hydrochloride-exposed embryos compared with the control group. Although this downregulation was not statistically significant, this decrease was striking with a 0.422-fold change in the fifth group. We demonstrated that pethidine hydrochloride affects neuronal development in chicken embryos. The teratogenic mechanism of pethidine hydrochloride is unclear; therefore, further investigation is required.

AgNOR as an effective diagnostic tool for determining the proliferative nature of different types of odontogenic cysts.

Objective:To determine the proliferative nature of different types of odontogenic cysts using silver-stained nucleolar organizer region (AgNOR) staining.Materials and Methods:Forty histopathological sections of each of odontogenic keratocyst, dentigerous, and radicular growth were taken into study. Two sections were produced using the paraffin block of separate cases, one was stained with hematoxylin and eosin and another segment was stained with silver nitrate method.Results:AgNOR staining shows black dots and other parts of nuclei show yellow-brown dots.Conclusion:AgNOR, which stain for NOR-related proteins, corresponds to cell multiplication. Their amount regarding the number of AgNORs per cyst can be a good marker of the proliferative action of the cell in aggressive cystic lesion having malignant potential.

Relationships between the structural and functional organization of the turtle cell nucleolus

The nucleolus is a multifunctional structure of the eukaryotic cell nucleus. However, its primary role is ribosome formation. Although the factors and mechanisms involved in ribogenesis are well conserved in eukaryotes, two types of nucleoli have been observed under the electron microscope: a tricompartmentalized nucleolus in amniotes and a bicompartmentalized nucleolus in other species. A recent study has also revealed that turtles, although belonging to amniotes, displayed a nucleolus with bipartite organization, suggesting that this reptile group may have carried out a reversion phenomenon during evolution. In this study, we examine in great detail the functional organization of the turtle nucleolus. In liver and spleen cells cultured in vitro, we confirm that the turtle nucleolus is mainly formed by two components: a fibrillar zone surrounded by a granular zone. We further show that the fibrillar zone includes densely-contrasted strands, which are positive after silver-stained Nucleolar Organizer Region (Ag-NOR) staining and DNA labelling. We also reveal that the dense strands condensed into a very compact mass within the fibrillar zone after a treatment with actinomycin D or 5,6-dichlorobenzimidazole riboside. Finally, by using pulse-chase experiments with BrUTP, three-dimensional image reconstructions of confocal optical sections, and electron microscopy analysis of ultrathin sections, we show that the topological and spatial dynamics of rRNA within the nucleolus extend from upstream binding factor (UBF)-positive sites in the fibrillar zone to the granular zone, without ever releasing the positive sites for the UBF. Together, these results seem to clearly indicate that the compartmentalization of the turtle nucleolus into two main components reflects a less orderly organization of ribosome formation.

Cytogenetic Studies in Glossogobius giuris (Hamilton, 1822) Through NOR-Staining and FISH

The Glossogobius giuris (Gobiidae), tank goby—a species of goby fish, is native mainly to freshwater and estuaries and has importance in the aquarium trade. It is classified as least concern under IUCN Red List. Live individuals of this species were collected from Loktak Lake in Manipur for cytogenetic investigation to reveal the nucleolar organizer region (NOR) through silver nitrate (AgNO3) and chromomycin A3 (CMA3) staining as well as DAPI staining and single-color fluorescence in situ hybridization (FISH) using 18S rDNA sequence as probe. Analysis of more than 50 metaphase chromosome complement (obtained from colchicine–potassium chloride–Carnoy’s fixation–Giemsa staining procedures) showed the presence of 46 diploid chromosome numbers with all telocentric having fundamental arm number as 46 without any heteromorphic pair. One pairs of silver-stained NORs, situated terminally on the telocentric chromosome, were observed. Similarly, one pair of CMA3-positive sites were observed on the chromosome that suggested abundance of GC-rich repetitive DNAs in this region. One pair of 18S rDNA positive sites was observed on the telocentric chromosomes using FISH. These karyological features can be useful markers in cytotaxonomy and conservation of this species.

Nucleolar alterations are reliable parameters to determine the cytogenotoxicity of environmental pollutants

Pollution generated by deposition of industrial activity waste in the environment without due care can lead to serious environmental consequences. Bioassays in higher plants are means of understanding the cytogenotoxic effects of these substances. In the present work, Allium cepa L. was used as a model species to assess nucleolar changes induced by environmental pollutants. The substances used were Methyl Methane Sulfonate (MMS), cadmium (Cd), Spent Potliner (SPL) and the herbicide Atrazine. Water was used as a negative control. The silver-stained nucleolar organizer region (AgNOR) assay was used making it possible to evaluate how nucleolar parameters (number of nucleoli per nucleus and nucleoli area) behave when facing stress caused by such pollutants. The results obtained showed a variation in the observed parameters: an increase in the number of nucleoli in the treated cells and tendency to a reduction in nucleolar area, indicating that the tested pollutants may have impaired nucleolar activity. In addition, it was possible to establish a relationship between the behavior of the nucleolus with other changes as plantlet growth, cell proliferation, and DNA damage.

Rapid Genomic and Genetic Changes in the First Generation of Autotetraploid Lineages Derived from Distant Hybridization of Carassius auratus Red Var. (\u2640)\u2009\xd7\u2009Megalobrama amblycephala (\u2642)

Autopolyploids are traditionally used to demonstrate multivalent pairing and unstable inheritance. However, the autotetraploid fish (4nRR) (RRRR, 4n = 200) derived from the distant hybridization of Carassius auratus red var. (RCC) (RR, 2n = 100) (♀) × Megalobrama amblycephala (BSB) (BB, 2n = 48) (♂) exhibits chromosome number (or ploidy) stability over consecutive generations (F1–F10). Comparative analysis based on somatic and gametic chromosomal loci [centromeric, 5S rDNA, and Ag-NORs (silver-stained nucleolar organizer regions)] revealed that a substantial loss of chromosomal loci during genome doubling increases the divergence between homologous chromosomes and that diploid-like chromosome pairing was restored during meiosis in the first generation of 4nRR lineages. In addition, a comparative analysis of genomes and transcriptomes from 4nRR (F1) and its diploid progenitor (RCC) exhibited significant genomic structure and gene expression changes. From these data, we suggest that genomes and genes diverge and that expression patterns change in the first generations following autotetraploidization, which are processes that might contribute to the stable inheritance and successful establishment of autotetraploid lineages.

Nucleolar organizer region banding in crossbred and non-descript pigs of India.

Aim:The objective of this experiment was to study the nucleolar organizer region (NOR)-banding pattern in Large White Yorkshire (LWY) crossbred and non-descript pigs and finding differences in the number of NORs between animals and between genetic groups.Materials and Methods:The experiment was carried out on 15 females, and 15 males of LWY crossbred and non-descript pigs to study NOR-banding pattern by employing ammoniacal silver staining technique.Results:A total of 63 and 65 number of good metaphases were prepared in LWY crossbred, and non-descript pigs and a total of 168 and 143 number of NORs were detected on the 8th and 10th chromosomes in both genetic groups, respectively. The mean number of NORs per metaphase was 2.67 and 2.20 in LWY crossbred and non-descript pigs, respectively. LWY crossbred pig had high mean number of silver-stained NORs (Ag-NORs) per metaphase compared to non-descript pig. In general, it was observed that the highest frequency of metaphases (%) examined had two number of NORs, while the lowest frequency (%) had four number of NORs. The number of NORs observed per metaphase on secondary constrictions of the 8th and 10th chromosome pair in both genetic groups ranged from 2 to 4. The Chi-square test of significance revealed that the observed frequencies do not differ significantly from the expected frequencies.Conclusion:The results confirmed differences across breeds in occurrence and number of NORs on chromosomes in pigs. The mean numbers of NORs present per metaphase vary between the animals indicating the existence of polymorphism for the number of NORs. A higher number of Ag-NORs were observed on chromosome pair 10 in both the genetic groups. It was concluded that NORs were more morphologically distinct and greater on chromosome pair 10 than on pair 8, which suggests a dominant role of chromosome 10 in the global production of ribosomal RNA.

Evaluation of Cellular Proliferative Activity in Patients with Actinic Cheilitis through Silver-stained Nucleolar Organizer Region Method

Introduction: Actinic cheilitis (AC) is a lesion potentially malignant that affects the lips after prolonged exposure to solar ultraviolet (UV) radiation. The present study aimed to assess and describe the proliferative cell activity, using silver-stained nucleolar organizer region (AgNOR) quantification proteins, and to investigate the potential associations between AgNORs and the clinical aspects of AC lesions. Materials and methods: Cases diagnosed with AC were selected and reviewed from Center of Histopathological Diagnosis of the Institute of Biological Sciences, Passo Fundo University, Brazil. Clinical data including clinical presentation of the patients affected with AC were collected. The AgNOR techniques were performed in all recovered cases. The different microscopic areas of interest were printed with magnification of *1000, and in each case, 200 epithelial cell nuclei were randomly selected. The mean quantity in each nucleus for NORs was recorded. One-way analysis of variance was used for statistical analysis. Results: A total of 22 cases of AC were diagnosed. The patients were aged between 46 and 75 years (mean age: 55 years). Most of the patients affected were males presenting asymptomatic white plaque lesions in the lower lip. The mean value quantified for AgNORs was 2.4 ± 0.63, ranging between 1.49 and 3.82. No statistically significant difference was observed associating the quantity of AgNORs with the clinical aspects collected from the patients (p > 0.05). Conclusion: The present study reports the lack of association between the proliferative cell activity and the clinical aspects observed in patients affected by AC through the quantification of AgNORs. Clinical significance: Knowing the potential relation between the clinical aspects of AC and the proliferative cell activity quantified by AgNORs could play a significant role toward the early diagnosis of malignant lesions in the clinical practice. Keywords: Actinic cheilitis, Proliferative cell activity, Silver-stained nucleolar organizer regions.

Histological and histomorphometric studies on the cerebellar cortex and silver stained nucleolus organizer regions of Purkinje neurons in chronic morphine-treated rats

Histological and histomorphometric studies on the cerebellar cortex and silver stained nucleolus organizer regions of Purkinje neurons in chronic morphine-treated rats

Comparative Study using Papanicolaou Stain and Silver-stained Nucleolar Organizer Region Counts in Exfoliative Smear of Oral Mucosa in Bidi Smokers and Nonsmokers.

Aim:The aim of this study is to compare the proliferative activity of exfoliated cells in bidi smoker's and nonsmoker's oral mucosa.Materials and Methods:The oral mucosal exfoliate smears were prepared from 40 individuals (20 nonsmokers and 20 smokers) with the age group ranging from 25 to 70 years, in and around Akola (Maharashtra). The Papanicolaou (PAP) stain and silver-stained nucleolar organizer region (AgNOR) were used to prepare cytogenic smear to evaluate the presence of cytological alterations, suggestive of inflammation, dysplasia, keratinization, and proliferative activity of epithelial cells. The present study involves PAP Class I and Class II smears. The obtained data were tabulated and statistically analyzed using statistical software IBM SPSS IBM Corp., Statistics for Windows, Version 20.0. Armonk, NY, USA: IBM Corp., and using t-test.Results:There was a significant difference in mean number of AgNORs/nucleus between nonsmokers (0.947 ± 0.2533) and smokers (3.021 ± 0.2256). There were 90% inflammatory changes observed in smokers whereas nonsmokers showed only 75% changes. PAP Class II changes, i.e., significant proliferative activity, were found between smokers and nonsmokers mucosa.Conclusion:A significant difference of AgNORs/nucleus was found between nonsmokers and smokers.

Quantitative assessment of silver-stained nucleolar organizer region in odontogenic cysts to correlate the growth and malignant potentiality.

Context:The most common and important odontogenic cyst involving jaws is the odontogenic keratocyst (OKC) or primordial cyst, the dentigerous cyst and the radicular cyst. These cysts all though do not show similar behavior, they all have the potentiality to recur. Silver nitrate staining of the nucleolar organizer regions (AgNORs) of the benign and malignant lesions is becoming very useful as a diagnostic indicator. Thus, the aim of this study is to assess the diagnostic potential of AgNORs in the cystic epithelium of common odontogenic cysts.Materials and Methods:Archived specimens of odontogenic cysts were stained with hematoxylin and eosin stain and AgNOR stain.Results:The comparative evaluation of the AgNOR counts was done among the three varieties of odontogenic cysts, i.e., radicular cysts, dentigerous cysts and OKC and were observed that the mean for OKC was significantly higher than that of radicular cyst.Conclusion:Therefore, AgNor could be used as an efficient tool for comparative evaluation of microscopic features such as epithelial thickness, surface keratinization and mural proliferation in dentigerous cyst to that of the AgNOR count.

CARM1 Modulators Affect Epigenome of Stem Cells and Change Morphology of Nucleoli

CARM1 interacts with numerous transcription factors to mediate cellular processes, especially gene expression. This is important for the maintenance of ESC pluripotency or intervention to tumorigenesis. Here, we studied epigenomic effects of two potential CARM1 modulators: an activator (EML159) and an inhibitor (ellagic acid dihydrate, EA). We examined nuclear morphology in human and mouse embryonic stem cells (hESCs, mESCs), as well as in iPS cells. The CARM1 modulators did not function similarly in all cell types. EA decreased the levels of the pluripotency markers, OCT4 and NANOG, particularly in iPSCs, whereas the levels of these proteins increased after EML159 treatment. EML159 treatment of mouse ESCs led to decreased levels of OCT4 and NANOG, which was accompanied by an increased level of Endo-A. The same trend was observed for NANOG and Endo-A in hESCs affected by EML159. Interestingly, EA mainly changed epigenetic features of nucleoli because a high level of arginine asymmetric di-methylation in the nucleoli of hESCs was reduced after EA treatment. ChIP-PCR of ribosomal genes confirmed significantly reduced levels of H3R17me2a, in both the promoter region of ribosomal genes and rDNA encoding 28S rRNA, after EA addition. Moreover, EA treatment changed the nuclear pattern of AgNORs (silver-stained nucleolus organizer regions) in all cell types studied. In EA-treated ESCs, AgNOR pattern was similar to the pattern of AgNORs after inhibition of RNA pol I by actinomycin D. Together, inhibitory effect of EA on arginine methylation and effect on related morphological parameters was especially observed in compartment of nucleoli.

Fractal analysis and the diagnostic usefulness of silver staining nucleolar organizer regions in prostate adenocarcinoma.

Pathological diagnosis of prostate adenocarcinoma often requires complementary methods. On prostate biopsy tissue from 39 patients including benign nodular hyperplasia (BNH), atypical adenomatous hyperplasia (AAH), and adenocarcinomas, we have performed combined histochemical-immunohistochemical stainings for argyrophilic nucleolar organizer regions (AgNORs) and glandular basal cells. After ascertaining the pathology, we have analyzed the number, roundness, area, and fractal dimension of individual AgNORs or of their skeleton-filtered maps. We have optimized here for the first time a combination of AgNOR morphological denominators that would reflect best the differences between these pathologies. The analysis of AgNORs' roundness, averaged from large composite images, revealed clear-cut lower values in adenocarcinomas compared to benign and atypical lesions but with no differences between different Gleason scores. Fractal dimension (FD) of AgNOR silhouettes not only revealed significant lower values for global cancer images compared to AAH and BNH images, but was also able to differentiate between Gleason pattern 2 and Gleason patterns 3–5 adenocarcinomas. Plotting the frequency distribution of the FDs for different pathologies showed clear differences between all Gleason patterns and BNH. Together with existing morphological classifiers, AgNOR analysis might contribute to a faster and more reliable machine-assisted screening of prostatic adenocarcinoma, as an essential aid for pathologists.

Quantitative estimation of AgNORs in normal, dysplastic and malignant oral mucosa

Silver stainable nucleolar organizer regions (AgNORs) have received a great deal of attention recently as their frequency within the nuclei is significantly higher in malignant cells than in normal, reactive or benign neoplastic cells. The objective of this study was to carry out a quantitative assessment of large and small AgNORs in oral normal mucosa, precancerous lesions and infiltrating squamous cell carcinomas. The study comprised 110 formalin-fixed, paraffin-embedded oral mucosal biopsies consisting of 30 oral dysplasia, 60 oral squamous cell carcinomas and 20 normal oral mucosa. AgNORs were counted in each nucleus, categorized as small, large and total number of AgNORs in each cell and their means were calculated. The mean value of small AgNORs, large AgNORs and total AgNORs increased gradually from normal mucosa to dysplastic lesions to squamous cell carcinomas. The study clearly indicates that in oral squamous cell carcinomas, AgNORs diminish in size as they increase in number. Further, AgNOR counts increase as the degree of malignant potential of the cell increases. By combining both the enumeration of AgNORs and their size, good distinction can be made between normal, dysplastic and infiltrating squamous cell carcinomas. This could help in the early diagnosis and prognosis of dysplastic mucosal lesions and their malignant transformation.

Evaluation of the efficacy of AgNOR as a proliferative marker in oral leukoplakia: A morphometric analysis

Background:Silver stainable nucleolar organizer regions (AgNORs) are replicatory markers which may have a place in objectively characterizing dysplasia.Materials and Methods:A study of various morphometric parameters related to AgNORs was performed in basal and parabasal layers of normal human oral epithelium, nondysplastic leukoplakia, and dysplastic leukoplakia employing photomicrographs of silver stained paraffin embedded sections using image analysis, to assess the usefulness of these parameters in distinguishing dysplastic leukoplakia from nondysplastic oral leukoplakia.Results:Out of various mean AgNOR related parameters, AgNOR count, area, perimeter, and proportion were found to be higher in dysplastic leukoplakia as compared to nondysplastic leukoplakia. On statistical analysis, AgNOR count showed statistically significant differentiation between dysplastic and nondysplastic leukoplakia. While other parameters can distinguish normal oral epithelium from dysplastic and nondysplastic leukoplakia.Conclusion:To conclude, the AgNOR count is the most appropriate marker to differentiate between dysplastic and nondysplastic leukoplakia.