Search

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.

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.

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.

Orb-weavers (Araneidae) are a diversified spider family comprising more than 3,100 species in more than 170 genera. Together with 13 other families, they con- stitute to superfamily Araneoidea. The presented thesis focuses on karyotype evo- lution of Araneidae, including its comparison with a related family Tetragnathidae. The results obtained from 19 araneid and four tetragnathid species confirm previ- ously postulated hypothesis that the ancestral karyotype of Araneoidea (including Araneidae) consists of 24 acrocentric chromosomes in males, including two acro- centric X chromosomes of system X1X20. However, there is a tendency of 2n decrease in some araneids due to centric fusions. In these cases, centric fusions affected most autosomes (and sometimes gonosomes as well); number of chromosome pairs de- creased from 11 to six. Three independent reduction events were detected in this thesis. Furthermore, pattern of nucleolar organizer regions (NORs) was studied in this thesis using fluorescent in situ hybridization, since data on evolution of this marker are scarce in spiders. Striking variability in NORs number was discovered, ranging from one to 13 loci. Remarkably, multiple centric fusions were always ac- companied by considerable increase of NORs number. In araneids and tetragnathids possessing...

This study aims to evaluate possible effects of chronic carbon monoxide (CO) exposure on argyrophilic nucleolar–organizer region (AgNOR)-associated protein synthesis in striated muscle cells. Eighteen rats were randomly divided into three groups. Rats in group II and group III were given CO gas (1000 and 3000 ppm, respectively) for 30 min a day for 7 d. Mean AgNOR number per nucleus and ratio of total AgNOR area to nuclear area (TAA/NA) were determined. Both TAA/NA ratio and mean AgNOR number provided information about the existence or absence of exposure. TAA/NA ratio was also an indicator of the level of exposure. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.

The nucleolus is required for ribosome biogenesis. Human cells have 2 or 3 nucleoli associated with nucleolar organizer region (NOR)-bearing chromosomes. An increase in number and altered nucleolar morphology define cancer cells. However, the mechanisms that modulate nucleolar morphology and function are unclear. Here we show that in addition to localizing at the nuclear envelope, lamin B2 localizes proximal to nucleolin at the granular component (GC) of the nucleolus and associates with the nucleolar proteins nucleolin and nucleophosmin. Lamin B2 knockdown severely disrupted the nucleolar morphology, which was rescued to intact and discrete nucleoli upon lamin B2 overexpression. Furthermore, two mutually exclusive lamin B2 deletion mutants, ΔHead and ΔSLS, rescued nuclear and nucleolar morphology defects, respectively, induced upon lamin B2 depletion, suggesting independent roles for lamin B2 at the nucleolus and nuclear envelope. Lamin B2 depletion increased nucleolin aggregation in the nucleoplasm, implicating lamin B2 in stabilizing nucleolin within the nucleolus. Lamin B2 knockdown upregulated nucleolus-specific 45S rRNA and upstream intergenic sequence (IGS) transcripts. The IGS transcripts colocalized with aggregates of nucleolin speckles, which were sustained in the nucleoplasm upon lamin B2 depletion. Taken together, these studies uncover a novel role for lamin B2 in modulating the morphology, dynamics, and function of the nucleolus.

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.

Studied has been the state of the nucleolar apparatus in lymphocytes of periphery lymphoid organs in laboratory animals vaccinated against plague and tularemia in order to evaluate predictive capability of the parameter in the context of pre-clinical evaluation of the vaccines under development, against particularly dangerous infections. For the detection of silver adjoining proteins, contained in the nucleolar organizer region (AgNOR), W.M.Howell and D.A.Black staining of semi-thin paraffin sections of lymphoid organs of the immunized BALB/c mice has been performed. For this purpose, ready-assembled panel, manufactured at BioVirtum, has been deployed. Under assessment of the functional state of immunogenesis organs in vaccinated against plague and tularemia animals revealed has been the increase in numbers of cells with three and more AgNOR-positive nucleoli in the nucleus of the lymphocytes of periphery organs of the biomodels’ immune system. It indirectly manifests proliferative capacity of immune system cellular component. Informativity of the quantitative evaluation of the cell proliferative activity by the reference to the status changes of AgNOR in the nuclei of immunogenesis organs’ lymphocytes makes it possible to entertain the possibility of introducing this method into the existing morphological vaccine quality assessment scheme at the stage of the pre-clinical trials.

AIM To evaluate the activity of hydroxyapatite (HAP) nanoparticles against the proliferation of hepatoma cells. METHODS HAP nanoparticles were prepared by homogeneous precipitation. The size distribution and morphology of these nanoparticles were determined by laser particle analysis and transmission electron microscopy, respectively. Xenograft tumor models of human hepatoma cells (Bel-7402) implanted in nude mice under the right scruff skin were established and divided into two groups: treatment and control. Once the xenograft tumor grew to a diameter of 0.8 cm, 0.2 ml HAP nanoparticle suspension was injected into the tumor every day for 2 weeks. The long and short diameters of the tumors were measured before and after HAP injection, and the inhibition rate of tumor growth was calculated. Paraffin tissue sections were prepared from xenograft tumors treated as above for 2 weeks, histologically stained for DNA and agyrophilic nucleolar organizer region (AgNORs), and immuno-histologically stained for proliferating cell nuclear antigens (PCNAs). The stained sections were examined by microscopy. Images of these sections were recorded and analyzed by image analysis system and relevant software for DNA content, AgNOR intensity, and PCNA expression in the nucleus, nucleoli, and hepatoma cells, respectively. RESULTS The HAP nanoparticles were uniformly distributed, with a size of 44.6 nm to 86.8 nm. Upon the local injection of the tumor with the HAP nanoparticles, the average volumes of the tumors were significantly reduced compared with those of the control group, which had a tumor inhibition rate of 51.32%. The DNA content, AgNOR intensity, and PCNA expression in the hepatoma cells were all significantly reduced (P < 0.01) compared with those in the control group. CONCLUSION HAP nanoparticles inhibit the proliferation of hepatoma cells in vivo.

Nucleolar alterations resulting from the action of either chemical or physical agents can serve as important genotoxicity biomarkers. In this study, the efficiency of AgNOR banding technique to identify the presence of nucleoli in micronucleus and assess nucleolar alterations in aberrant cells of Allium cepa was evaluated. Seeds of this plant were exposed to both water samples from a river that receives untreated urban effluent and to the trifluralin herbicide (0.84 mg/L concentration), both analyzed in two different seasons (summer and winter seasons). Samples induced significant frequencies of chromosomal and nuclear aberrations and micronuclei, as observed in cells submitted to conventional chromosomal staining. The herbicide caused a significant increase in the number of nucleoli and micronuclei, interpreted as due to the elimination of excessive nucleolar material resulting from polyploidization. The use of the AgNOR technique enabled the identification of both the presence of the nucleolus in some micronuclei and the nucleolar organizer region (NOR) behavior of aberrant cells. The NOR-banding technique showed to be an efficient tool for studying the genotoxic effects caused by a xenobiotics and a complex environmental sample.

Nucleoli are the sites of ribosome biogenesis and the largest membraneless subnuclear structures. They are intimately linked with growth and proliferation control and function as sensors of cellular stress. Nucleoli form around arrays of ribosomal gene (rDNA) repeats also called nucleolar organizer regions (NORs). In humans, NORs are located on the short arms of all five human acrocentric chromosomes. Multiple NORs contribute to the formation of large heterochromatin-surrounded nucleoli observed in most human cells. Here we will review recent findings about their genomic architecture. The dynamic nature of nucleoli began to be appreciated with the advent of photodynamic experiments using fluorescent protein fusions. We review more recent data on nucleoli in Xenopus germinal vesicles (GVs) which has revealed a liquid droplet-like behavior that facilitates nucleolar fusion. Further analysis in both XenopusGVs and Drosophila embryos indicates that the internal organization of nucleoli is generated by a combination of liquid-liquid phase separation and active processes involving rDNA. We will attempt to integrate these recent findings with the genomic architecture of human NORs to advance our understanding of how nucleoli form and respond to stress in human cells.

The nucleolus, the largest sub-nuclear structure, forms around arrays of ribosomal RNA genes, termed nucleolar organizer regions (NORs). As the site of ribosome biogenesis, nucleolar function is intrinsically linked to cellular growth and proliferation control. Nucleolar morphology has long been used as a prognostic marker of cancer. This is one of the many examples of how aberrant nucleolar function is related to disease. The biochemistry of ribosome biogenesis has been extensively studied, leading to a comprehensive understanding of the process. However, we know relatively little about how the nucleolus is formed, and its relationship with NORs. Each diploid human cell contains around 600 copies of the human ribosomal RNA gene (rDNA) arranged in tandem repeats. The rDNA repeat is composed of the pre-ribosomal RNA coding sequences separated by non-transcribed intergenic spacer regions (IGS). NORs are located on the short arms of all five acrocentric chromosomes. Upstream Binding Factor (UBF), a nucleolar specific HMG-box protein, is essential for establishing and maintaining the activity status of ribosomal RNA genes. It binds constitutively across the whole of the rDNA repeat and generates a decondensed, transcriptionally permissive chromatin state. NORs may either exist in a UBF bound, transcriptionally active state, or a silent state. During mitosis, active, UBF bound NORs, are achromatic and therefore are referred to as secondary constrictions. In this thesis, I characterise the rDNA distribution across NORs for several cell lines, along with their activity status. This was accomplished using ImmunoFISH techniques. I determined that the majority of NORs having a detectable number of rDNA genes are UBF loaded and therfore active. To study how NORs form nucleoli, and the role of UBF in this process, I depleted UBF in these cells. I examined the effects on the activity status of NORs and their ability to participate in nucleolar biogenesis. Interestingly, I found that NORs were inactivated in a hierarchical manner, with NORs having smaller numbers of rDNA repeats being preferentially inactivated and dissociated from nucleoli. Similar results were observed in growth inhibited cells, illustrating for the first time that the activity status of NORs can be modulated in response to changes in cell state. In order to better describe the nature of the localization of UBF to the rDNA in nucleoli, I performed FRAP experiments to study UBF dynamics at these loci. This was done using a cell line expressing an endogenously tagged UBF_GFP gene, thereby ensuring the biological relevance of results obtained. A population of cells in which UBF dynamics was reduced was identified. This population has not been previously described. I then illustrated that driving cells into a quiescent state by either serum deprivation, or contact inhibition resulted in a similar reduction in UBF dynamics. The driving force for UBF localization and interaction with the rDNA is poorly understood. I analysed the N-terminus of UBF to determine if it plays some role in these functions. The first ~100 aa of this protein have been shown to contain both an extensively characterised dimerization domain and a putative SANT-like domain. Mutation of three conserved residues within the SANT-like domain abrogates localization. My results indicate that dimerization is crucial for correct localization of UBF, and furthermore suggest that the N-terminus has histone tail binding capabilities. In the final discussion I combine my findings about the behaviour of active NORs with recently described research regarding the biophysical properties of nucleoli and propose a refined model of nucleolar formation.

Nucleolar organizer regions are nucleolar components that contain proteins that are stained selectively by silver methods; they can be identified as black dots throughout the nucleolus and are known as silver binding nucleolar organizer regions (AgNOR). The number of AgNOR is related to the cell cycle and the proliferative activity of the cells. We investigated AgNOR using exfoliative cytology smears of potentially malignant oral lesions. Eighty individuals were divided into four equal groups: healthy controls, oral leukoplakia, oral submucous fibrosis and oral squamous cell carcinoma. The mean number of AgNOR in each study group gradually increased from control to oral leukoplakia to oral submucous fibrosis to oral squamous cell carcinoma. The proliferative index was increased in the oral premalignant and malignant patients compared to normal subjects. The mean AgNOR size gradually increased from control to oral leukoplakia to oral submucous fibrosis to oral squamous cell carcinoma. Spherical shaped AgNOR were most common in controls, whereas large, clustered and kidney shapes were most common in oral squamous cell carcinoma. Multiparameter analysis of AgNOR in oral exfoliative smears is a simple, sensitive and cost-effective method for differentiating premalignant from malignant lesions and can be used in conjunction with routine cytomorphological evaluation.

Hoplias malabaricus comprises seven karyomorphs (A-G) and evolutionary units have been described in some of them. In this study, the karyotypic composition and genomic organization of individual H. malabaricus from Central Amazon are described and to verify whether they can be classified according to known karyomorphs. Individuals from the Ducke Reserve have 2n = 42 chromosomes, similar to karyomorph A. Individuals from Catalão Lake and Marchantaria Island exhibit 2n = 40 chromosomes, similar to karyomorph C. Regarding the constitutive heterochromatin, individuals from all locations present centromeric/pericentromeric blocks, in addition to some bitelomeric and interstitial markings. The number of chromosomes with nucleolar organizer region, 5S rDNA and 18S rDNA sites varied among the different locations. The Rex 3 element has a compartmentalized distribution at the terminal and centromeric regions of most chromosomes, with subtle differences among populations. Fluorescence in situ hybridization performed with a telomeric probe allowed the detection of these regions only at the terminal ends of the chromosomes. Thus, only the chromosomal macrostructure (karyomorphs A-G) is not sufficient to establish evolutionary units within the H. malabaricus group, considering differences in the genome organization that are found among their populations. Such differences in the genomic organization could be mainly caused by the sedentary habits of this species.

The nucleolus is an important nuclear structure where transcription of ribosomal DNA (rDNA) takes place. During mitotic division, the nucleolus passes through different processes that inactivate rDNA transcription; in meiosis, its reassembly takes place during telophase II. The objective of this study was to identify the activity patterns and localization of nucleolar organizer regions (NORs) during meiotic division in fish species of the family Curimatidae. For this analysis, the meiotic division in five curimatid species was studied using silver nitrate impregnation, fluorescent in situ hybridization (FISH), and base-specific fluorochrome staining. Silver nitrate staining indicated the presence of a nucleolus in interphase nuclei, one chromosome pair in the spermatogonial metaphases, and one bivalent at the pachytene stage. No Ag-NORs were identified for cells at the diplotene, diakinesis, metaphase I, or metaphase II stages; however, FISH confirmed the presence of Ag-NORs in the nuclei, in spermatogonia, and at the pachytene phase. FISH identified this region during the other stages of meiosis, as did fluorochrome CMA3 staining, which revealed fluorescent marks corresponding to NORs during all stages of meiosis analyzed. The gene activity and localization of this ribosomal sequence during the different stages involved will also be discussed.

Trisomy mapping is a powerful method for assigning genes to chicken microchromosome 16 (GGA 16). The single chicken nucleolar organizer region (NOR), the 2 major histocompatibility complex regions (MHC-Y and MHC-B), and CD1 genes were all previously assigned to GGA 16 using trisomy mapping. Here, we combined array comparative genomic hybridization with trisomy mapping to screen unassigned genomic scaffolds (consigned temporarily to chrUn_random) for sequences originating from GGA 16. A number of scaffolds mapped to GGA 16. Among these were scaffolds that contain genes for olfactory (OR) and cysteine-rich domain scavenger (SRCR) receptors, along with a number of genes that encode putative immunoglobulin-like receptors and other molecules. We used high-resolution cytogenomic analyses to confirm assignment of OR and SRCR genes to GGA 16 and to pinpoint members of these gene families to the q-arm in partially overlapping regions between the centromere and the NOR. Southern blots revealed sequence polymorphism within the OR/SRCR region and linkage with the MHC-Y region, thereby providing evidence for conserved linkage between OR genes and the MHC within birds. This work localizes OR genes to the vicinity of the chicken MHC and assigns additional genes, including immune defense genes, to GGA 16.

Argyrophilic proteins associated with chromosome nucleolar organizer regions (Ag-NOR proteins) were studied in lung squamous-cell carcinoma cells. After routine staining with silver nitrate, the area index and coefficient of variations of Ag-NOR protein were estimated by computer-aided image analysis. The Ag-NOR protein area indexes of tumor cells differed in clinical morphological variants of squamous-cell cancer (differing by T and N parameters, size of the primary node

The use of Toombak has been reported to play a major role in the etiology of oral cancer in Sudan. The cellular proliferative activity on the oral epithelium of 210 Toombak dippers was assessed by applying the micronuclei frequency, mean argyrophilic nucleolar organizer region (AgNOR) counts, Papanicolaou method, and 1% crystal violet stain. Participants were divided into 3 groups: 200 were apparently healthy individuals, 100 were Toombak users (cases), 100 were non-tobacco users (control) and 10 were patients with oral squamous cell carcinomas. Cytological atypia was identified among 4 (4%). Toombak users and was not found among the control group (P

Gossypium mustelinum ((AD)4) is one of five disomic species in Gossypium. Three 45S ribosomal DNA (rDNA) loci were detected in (AD)4 with 45S rDNA as probe, and three pairs of brighter signals were detected with genomic DNA (gDNA) of Gossypium D genome species as probes. The size and the location of these brighter signals were the same as those detected with 45S rDNA as probe, and were named GISH-NOR. One of them was super-major, which accounted for the fact that about one-half of its chromosome at metaphase was located at chromosome 3, and other two were minor and located at chromosomes 5 and 9, respectively. All GISH-NORs were located in A sub-genome chromosomes, separate from the other four allopolyploid cotton species. GISH-NOR were detected with D genome species as probe, but not A. The greatly abnormal sizes and sites of (AD)4 NORs or GISH-NORs indicate a possible mechanism for 45S rDNA diversification following (AD)4 speciation. Comparisons of GISH intensities and GISH-NOR production with gDNA probes between A and D genomes show that the better relationship of (AD)4 is with A genome. The shortest two chromosomes of A sub-genome of G. mustelinum were shorter than the longest chromosome of D sub-genome chromosomes. Therefore, the longest 13 chromosomes of tetraploid cotton being classified as A sub-genome, while the shorter 13 chromosomes being classified as D sub-genome in traditional cytogenetic and karyotype analyses may not be entirely correct. Wu Q, Liu F, Li S, Song G, Wang C, Zhang X, Wang Y, Stelly D, Wang K (2013) Uniqueness of the Gossypium mustelinum genome revealed by GISH and 45S rDNA FISH. J. Integr. Plant Biol. 55(7), 654–662.

Genetic variability was assessed among three species of genus Channa, namely C. gachua, C. punctata and C. striata, using karyological tools including karyomorphology, silver nitrate and chromomyci...

Hepatocellular carcinoma (HCC) is the most lethal cancer and leading cause of cancer related death in the world. For more than a decade, natural dietary agents including fruits, vegetables and spices have drawn an immense deal of attention in the prevention of cancer. Naringin (4′,5,7-trihydroxy flavonone 7-rhamnoglucoside), a member of the flavanoid group, has been reported to possess chemopreventive potential against hepatocellular carcinoma in experimental rats. The aim of the present study was to evaluate the effect of naringin on antiproliferative and apoptotic effect against diethylnitrosamine (DEN)-induced experimental liver carcinogenesis in male Wistar rats model. Rats administered with DEN showed increase in the levels of argyrophillic nucleolar organizer region (AgNOR)/nuclei and Proliferating Cell Nuclear Antigen (PCNA), which was significantly reduced upon naringin treatment (40 mg/kg body weight). DNA fragmentation and transmission electron microscopy study of liver tissue also supports the chemopreventive potential of naringin. In conclusion, this study provides evidence that naringin exhibits potent anti-carcinogenic effect against DEN-induced hepatocellular carcinoma, which is attributed to its antiproliferative and apoptotic properties.

Background: Argyrophilic nucleolar organizer region is higher in malignant nuclei as compared to reactive and benign nuclei. The main objective of this study was to evaluate the role of Argyrophilic nucleolar organizer region and its extent in differentiating benign and malignant lesions, particularly with respect to follicular neoplasms of the thyroid. Materials and Methods: This was a prospective, cross sectional study which included 110 patients presenting with thyroid swelling. The fi ne needle aspiration smears were studied by conventional methods and silver staining for Argyrophilic nucleolar organizer region. In 50 cases, diagnosis was confi rmed by histopathology. The Argyrophilic nucleolar organizer region count was done and the mean Argyrophilic nucleolar organizer region count per nucleus was calculated along with pattern of distribution. Results: Mean Argyrophilic nucleolar organizer region count was higher in neoplastic as compared to non-neoplastic and infl ammatory lesions. Papillary carcinoma had the highest mean Argyrophilic nucleolar organizer region count (5.40 ± 0.86) and the lowest count was seen in Hashimoto’s thyroiditis (2.10 ± 0.36). Higher mean Argyrophilic nucleolar organizer region count was recorded in follicular carcinoma (4.84 ± 1.42) as compared to follicular adenoma (3.5 ± 0.27) which was found to be statistically signifi cant (P Conclusion: Argyrophilic nucleolar organizer region study of thyroid can be used as an additional diagnostic adjunct with cytomorphological features to differentiate benign and malignant follicular neoplasms. Journal of Pathology of Nepal (2013) Vol. 3, No.1, Issue 5, 361-366 DOI: http://dx.doi.org/10.3126/jpn.v3i5.7859

WOS: 000315252000006 PubMed: 23767292 ARSLAN A., ZIMA J., YORULMAZ T., GOZUTOK S., TOYRAN K. 2013. Chromosome banding pattern in fat dormouse and bank vole (Mammalia: Rodentia) from Turkey. Folia Biologica (Krakow) 61: 47-51. The chromosome banding pattern (C-banding, AgNOR staining) was studied in isolated populations of two species of rodents from Turkey, Glis glis and Myodes glareolus. A single nucleolar organizer region was localized in an autosomal pair in the complement of G. glis. Centromeric C-heterochromatin blocks and seven pairs of NOR-bearing autosomes were observed in the complement of M glareolus. A metacentric Y chromosome was found in the M glareolus males examined. The detailed structure of karyotypes and the banding patterns differ from some previously published results.

Objective: Quid chewing is associated with an increased risk of oral cancer. This study aims to analyze argyrophilic nucleolar organizer region (AgNOR) counts along with Papanicolaou (PAP) staining in exfoliative smears of quid chewers and non-chewers to correlate quid chewing habits with possible early cytological changes in apparently normal buccal mucosa. Study Design: Exfoliative smears were obtained from normal buccal mucosa of 30 male quid chewers and non-chewers. The smears were stained using the AgNOR silver staining technique to evaluate the proliferative activity and PAP for cytological appearance. Results: Statistically higher AgNOR counts were observed in chewers as compared to non-chewers. The difference in the mean percentage of nuclei having ≥5 AgNORs in both groups was statistically significant (p = 0.001). In chewers, PAP showed 77% with class I and the remaining 23% were class II, while the non-chewers showed only class I cytology. AgNOR counts between chewers and non-chewers having class I cytological appearance demonstrated a greater mean AgNOR count in chewers (p = 0.0001). Conclusion: Quid chewing seems to have a definite role in promoting proliferative activity of apparently normal buccal mucosal cells. Exfoliative cytological assessment of a combination of AgNOR counts and PAP has the potential for prediction of early quid-associated cellular changes before the appearance of clinical premalignant and malignant lesions.

INTRODUCTION There is a need to assess the value of the novel potentially useful biomarkers in ovarian tumors. The aim of study was to assess the value of sAgNOR analysis in ovarian serous epithelial tumors. MATERIAL AND METHODS The analysis was performed in ovaries from 113 patients treated operatively due to serous ovarian tumors (30 adenomas, 14 borderline tumors and 69 cancers). After silver staining of paraffin specimens from surgery, sAgNOR in tumor cells was analyzed. Additionally, the value of the argyrophilic nucleolar organizer region area/nucleus ratio (sAgNOR) in the prediction of disease-free survival (DFS) and overall survival (OS) in 52 patients with serous ovarian cancer with complete follow-ups in November 2009 was evaluated. Age, grading, radicality of surgery and FIGO staging were analyzed as additional factors. RESULTS SAGNOR IN ADENOMAS, BORDERLINE TUMORS AND CANCERS WAS IN THE FOLLOWING RANGES: (0.73 ±0.23) × 10(6), (0.81 ±0.18) × 10(6) and (0.96 ±0.33) × 10(6) [AgNOR/cm(2)] respectively. In cancers from G1 to G3 sAgNOR was (1.02 ±0.32) × 10(6) (G1), (0.98 ±0.37) × 10(6) (G2) and (0.82 ±0.24) × 10(6) (G3) [AgNOR/cm(2)] respectively. In univariate analysis, but not in multivariate analysis, staging negatively correlated with better DFS and OS. sAgNOR, age of patients, grading and radicality of surgery were not associated with DFS or OS in either univariate or multivariate analysis. CONCLUSIONS sAgNOR analysis is not sufficient to precisely characterize cellular kinetics in serous ovarian tumors, and the analysis of sAgNOR, mAgNOR and pAgNOR should be performed commonly. The prognostic significance of sAgNOR in patients with serous ovarian cancer was not proven.

Background: Argyrophilic Nucleolar Organizer Region technique has a potential value in the diagnosis of malignancy and can be used in cases with equivocal and inconclusive cytological picture. The purpose of this study was to evaluate mean Argyrophilic Nucleolar Organizer Region count and Subjective Argyrophilic Nucleolar Organizer Region Pattern Assessment score in fi ne needle aspirates of breast lumps. Materials and Methods: A prospective, cross sectional study consisting of 110 patients (38 malignant and 72 benign) with clinically palpable breast lumps who underwent fi ne needle aspiration followed by subsequent histopathologic examination were included. Fine Needle Aspiration smears were studied by conventional methods and silver staining for Argyrophilic Nucleolar Organizer Regions. Histopathologic diagnosis was taken as the gold standard. Results: Argyrophilic Nucleolar Organizer Region count and Subjective Argyrophilic Nucleolar Organizer Region Pattern Assessment score were helpful in differentiating benign from malignant lesions. Mean Argyrophilic Nucleolar Organizer Region count and Subjective Argyrophilic Nucleolar Organizer Region Pattern Assessment score were 2.63 ± 1.36 and 6.26 ± 1.19 respectively in benign lesions while they were 8.42 ± 2.53 and 10.05 ± 2.22 respectively in malignant lesions. With few exceptions, cases with high counts had high scores. Conclusion: Mean Argyrophilic Nucleolar Organizer Region AgNOR count and Subjective Argyrophilic Nucleolar Organizer Region Pattern Assessment score provide useful information regarding cellular proliferation. Both count and score have comparable diagnostic potential but the latter is a more convenient and rapid method for Argyrophilic Nucleolar Organizer Region evaluation. DOI: http://dx.doi.org/10.3126/jkmc.v1i1.7248 Journal of Kathmandu Medical College, Vol. 1, No. 1, Issue 1, Jul.-Sep., 2012 pp.3-9

Astyanax taeniatus occurs in coastal areas of southeastern Brazil, and it is very abundant in the Upper Doce River Basin. Our objective was to study C-, argyrophilic nucleolar organizer region (Ag-NOR) and fluorescent in situ hybridization (FISH) banding patterns using 5S, 18S, CA(15), and GA(15) repetitive DNA probes on a population of A. taeniatus present in the Piranga River, in the Doce Basin. Two syntopic cytotypes were found, both with 2n = 50: cytotype A (14m + 12sm + 16st + 8t) and cytotype B (10m + 14sm + 18st + 8t). In both cytotypes, heterochromatic blocks occurred in all the chromosomes; Ag-NOR sites were multiple, ranging from four to eight. The 5S rDNA probe marked eight chromosomes in both cytotypes, a unique condition within Astyanax, suggesting a recent divergence between these cytotypes. The 18S rDNA probe differed between the cytotypes, marking 10 and 8 chromosomes in cytotypes A and B, respectively. CA(15) and GA(15) FISH patterns were mainly subtelomeric, but CA(15) showed centromeric markings that were diagnostic for each cytotype. Although overall cytogenetic evidence suggests that these cytotypes are closely related, morphological and molecular data in progress will provide further hypothesis test on their phylogenetic relationship.

Lymphoid tumors comprise one of the most common groups of tumors in domestic animals. Lymphosarcoma is expressed as a specific multicentric form in calvesupto six months of age (sporadic) and in adult cattle (enzootic); and as thymic form in young cattle. Eight calves of both sexes aged below six months were necropsied in the department of veterinary Pathology, college of Veterinary Science, Tirupati. During necropsy impression smears, represented tissue samples were collected for Cytopathology, histopathology, AgNOR count and immunohistochemical studies. Cytological smears revealed lymphocytes, prolymphocytes and lymphoblasts with anaplastic changes. Histopathologically, partial to complete obliteration of architecture due to the replacement of normal tissue by lymphoblastic cells in lymphnodes and other visceral organs. The mean AgNOR count of the lymphosarcoma was 4.25 and it appear as a round to irregular, dark brown to black dots of varying sizes in the nuclei. Positive expression of PCNA and Ki67 was noticed in lymphnode, liver, kidney and lung was observed. The labeling index of PCNA and Ki-67 expression and distribution of immunopositive cells may be helpful in the early diagnosis and prognosis of malignant tumors. Hence, AgNOR, PCNA and Ki-67 indices can be used as reliable markers of cell proliferation and malignancy.

Background Serous effusion smears reported as “suspicious for malignancy” pose problems in clinical management. Silver staining for argyrophilic nucleolar organizer regions (AgNOR) has proved useful in making a cytopathologic differential diagnosis between benign and malignant cells. Nucleolar organizer regions(NORs) are loops of DNA located in acrocentric chromosomes. These NORs are visualized by silver staining technique that recognizes these argyrophilia associated proteins which are increased in malignancy. Objective This study aimed to distinguish reactive mesothelial cells from malignant cells in serous effusions using these NORs. Methods A total of 174 serous effusions received at the Department of Pathology, TUTH, during a period of one year were included in the study. Smears were studied by conventional Papanicolaou and Giemsa stains. AgNOR counts, variation in size and dispersion of AgNOR dots in smears were graded and compared in malignant and non-malignant effusions. Results Mean AgNOR counts of 10.43±0.73 and 10.21±0.51 in malignant peritoneal and pleural effusions, respectively, were significantly (p

The Ojcow National Park is situated in southern Poland in an area of Jurassic limestone, which determines the hydro- chemistry of the water in the River Pr�� dnik. The geochemical index of the sediment in the River Pr�� dnik indicated it is moderately polluted with Pb and Zn, and heavily polluted with Cd compared to unpolluted sediment. The effect of natural and anthropogenic sources on the sediment in the River Pr�� dnik and in appearing of structural and functional alterations in the salivary gland chromo- somes of two species of Chironomidae, Micropsectra pallidula and Polypedilum convictum, was investigated. Two types of chromo- somal rearrangements (inherited and somatic) were identified in the species studied. Inherited heterozygous inversions occurred at a higher frequency (between 5.55%-57.81%) and may have local adaptive value. In M. pallidula a karyotype divergence consisting of fixed chromosome inversions on arms B and E was recorded. As somatic chromosome rearrangements can be caused by stress agents, we suggest that the somatic aberrations in both of the species studied indicate the existence of pollution, i.e. induced stress. On the basis of these somatic rearrangements the somatic index of both species was defined: M. pallidula - 0.346, P. convictum - 0.555. In addition to these rearrangements functional alterations in key structures, Balbiani rings (BRs) and the nucleolar organizer region (NOR) located on chromosome EF, which significantly decreased their transcriptional activity, were recorded in M. pallidula. Changes in the appearance of the telomere region on chromosome G in P. convictum was considered to be a response to the environ- mental conditions in the River Pr�� dnik. It was shown that polytene chromosomes are very sensitive to environmental changes and can be used to detect pollutants in aquatic ecosystems.

The work was aimed at determining the number and morphology of nucleoli in the prophase of the first meiotic division in domestic cattle males. The use of AgNO3 staining, commonly applied in cytogenetics for the identification of nucleolar organiser regions, made it possible to identify nucleoli in first-order spermatocytes. One nucleolus was identified in each analysed cell. Considerable morphological differentiation of the nucleoli during the prophase of the first meiotic division, particularly in leptotene, unobserved in other farm animal species, was noticed. Dark-hued grain-like structures were found within the disintegrating nucleoli, corresponding approximately or exactly to the number of the nucleolar organiser regions in the domestic cattle karyotype. Dark areas were identified in the selected prometaphase chromosomes. Their number corresponded with the number of active NORs defined in the domestic cattle karyotype.

Classical and molecular cytogenetic (18S rDNA, telomeric sequence, and LINE-1 retrotransposon probes) studies were carried out to contribute to an understanding of the organization of repeated DNA elements in the Amazon River dolphin (boto, Inia geoffrensis). Twenty-seven specimens were examined, each presenting 2n = 44 chromosomes, the karyotype formula 12m + 14sm + 6st + 10t + XX/XY, and fundamental number (FN) = 74. C-positive heterochromatin was observed in terminal and interstitial positions, with the occurrence of polymorphism. Interstitial telomeric sequences were not observed. The nucleolar organizer region (NOR) was located at a single site on a smallest autosomal pair. LINE-1 was preferentially distributed in the euchromatin regions, with the greatest accumulation on the X chromosome. Although the karyotype structure in cetaceans is considered to be conserved, the boto karyotype demonstrated significant variations in its formula, heterochromatin distribution, and the location of the NOR compared to other cetacean species. These results contribute to knowledge of the chromosome organization in boto and to a better understanding of karyoevolution in cetaceans.

Background: Nucleolar organizer regions (NOR) are associated with proliferative activity and represent a diagnostic and prognostic marker. Materials and Methods: Smears were taken from smokers, tobacco chewers, oral squamous cell carcinoma patients, and normal subjects and evaluated by 2 silver-staining nucleolar organizer region (AgNOR) counting methods: (1) mean number of AgNORs per nucleus (mAgNOR); and (2) percentage of nuclei with >3 and >5 AgNORs (pAgNOR). Results: A statistically significant difference was observed between normal subjects, smokers, tobacco chewers, and oral cancer patients and between tobacco chewers with and without lesion. No significant difference was observed between tobacco chewers and smokers except in the percentage of >5 criteria. Conclusions: AgNOR enumeration using noninvasive methods, such as the cytobrush appears to be useful technique in distinguishing between normal mucosa, mucosa with and without lesions exposed to carcinogens, such as tobacco and frank oral carcinoma.