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Background and Objectives: It is of great importance to obtain information about the severity of ischemic damage and duration of testicular torsion for an effective treatment strategy. Nucleolarorganizing regions (NORs) are sites of the ribosomal genes composed of ribosomal DNA and proteins. Post-silver staining NORs are termed “AgNOR”. Since AgNORs clearly reveals the self-renewal potential of cells damaged in ischemic events, we performed the current study. Materials and Methods: The study was carried out in four groups as control, sham, early, and late T/D. In the surgical groups, testes were corrected after a 4-h ischemia period. Testicular tissue samples were taken on the third day after detorsion in group 1, 2, 3, and on the tenth day after detorsion in group 4. TUNEL and silver stainings were applied to all samples. Results: The differences were significant among the groups for both mean AgNOR number and total AgNOR area/total nuclear area (TAA/TNA). Moreover, the differences between control and early torsion-detorsion (T/D), between control and late T/D, between sham and early T/D, between sham and late T/D, and between early T/D and late were statistically significant for AgNOR amount. Furthermore, statistically significant differences among the groups for an average number of apoptotic cells per tubule and the percentage of apoptotic tubule values were detected. Discussion: The apoptotic index gives the ratio of cells that are damaged and will die in a programmed way and cells that remain intact, rather than show the viability of the returning testicle. However, by measuring cells that regenerate with AgNOR, we can show not only those that survive but also cells that can repair themselves. Conclusion: AgNOR proteins are usable for the early observation of ischemic injury levels. The amount of AgNOR protein can enlighten us about the extent of testicular damage after T/D treatment. It may also help the physician in the development of effective treatment strategies for cases. [ABSTRACT FROM AUTHOR]

Nucleolus Organizer Regions (NORs) are defined as nucleolar components containing argyrophilic proteins selectively stained by silver methods (AgNORs). Several investigations have shown the AgNOR quantity and area represent a valuable parameter of cell kinetics, since they reflect the level of activity and cellular proliferation. This article addresses an evaluation of the functional activity and relation between days of pregnancy and proliferative capacity of trophoblastic mononucleate and binucleate cells from bovine placentomes. Both the number and size of AgNORs were determined in different phases of gestation by silver nitrate staining in conventional histological slides. The results showed a significant increase (from 1 to 12 AgNORs) in the number of AgNORS per trophoblastic mononucleate cell in the 3rd trimester, with predominance of 4-6 AgNORs/cell. In the 1st and 2nd trimesters, the number ranged between 1 and 9 AgNORs/cell, with predominance of 1-3 AgNORs. No significant differences were observed between the 2nd and 3rd trimesters, but in the first, in binucleate cells (19-27 and 10-18 AgNORs/cell, respectively) - this number was higher than the one registered in trophoblastic mononucleate cells in the same period. Thus, AgNORs can be used as markers of the proliferative placental cell cycle and established a relation between number of AgNORs and days of gestation. This relation can be used for diagnoses and prognoses of several placental pathologies, including pregnancy losses from manipulated embryos. [ABSTRACT FROM AUTHOR]

The first chromosomal analysis of Salween shovelhead catfish (Sperata acicularis) was undertaken by classical cytogenetic and fluorescence in situ hybridization (FISH) techniques in the present study. Ten male and ten female fish were obtained from Salween River, Mae Hong Son Province, Northern Thailand. The mitotic chromosome preparation was directly performed from kidney tissues. Conventional Giemsa staining, Ag-NOR staining, and molecular cytogenetics techniques with FISH using 5S, 18S rDNAs, and microsatellites d(CA)15 and d(GC)15 repeats as probes were conducted. The results indicated that the diploid chromosome number of S. acicularis was 2n = 56. The fundamental number (NF) was 110 both for males and females. The karyotype is composed of 18 large metacentric, 10 large submetacentric, 14 medium metacentric, 12 medium submetacentric and 2 medium acrocentric chromosomes; sex chromosomes could not be identified. NORs localized at the subtelomeric region of the short arm of metacentric chromosome pair 3, which coincides with location of 18S rDNA probe. 5S rDNA probe signal was detected on the short arm of the metacentric chromosome pairs 5 and 8. The distribution patterns of each analysed microsatellite repeat on the chromosomes differed from each other. Microsatellite d(CA)15 repeats were highly accumulated at telomeric regions of all chromosome pairs, and throughout the chromosome in some pairs while the microsatellite d(GC)15 repeats were scattered and less accumulated in some chromosome pairs. Overall, we present the karyotype of S. acicularis providing insights into species' evolution and enabling undoubtedly species identification. [ABSTRACT FROM AUTHOR]

Cytogenetically, out of 262 species, only three species of family Platystictidae has been reported worldwide. Present study has been undertaken to study chromosome complement and its characterization of more species of this family. Cytogenetic analyses of Protosticta sanguinostigma Fraser, 1992 and Protosticta uncata Fraser, 1931 of family Platystictidae, collected from Andretta, Himachal Pradesh, India have been carried out on the basis of conventional staining, C-banding and silver nitrate staining. Both the species possess n=13m as haploid chromosome number and X0-XX sex determining mechanism. One large bivalent is present in all the meiotic stages of P. sanguinostigma which is considered as the species specific character. Chromosome complement of both the species shows variation in distribution of C-bands and Nucleolar organizer regions (NORs). Cytologically, both the species have been described for the first time. [ABSTRACT FROM AUTHOR]

The biologic behavior of the oral lesions can be determined by their active phases of cell division, cells entering the cell cycle and their proliferation. AgNORs (argyrophilic nucleolar organizer regions) staining is the one of the cytochemical technique used to evaluate the cell proliferation of oral lesions. Tumor cells in premalignant and malignant conditions usually exhibits a rise in synthesis of abnormal proteins and proportionately there is a increase in the AgNOR material. The aim of this study was to review the concepts of proliferative activity of cells of malignant and premalignant conditions through the AgNORs staining procedure and thereby proving the usefulness of AgNORs in diagnosing the oral lesions. [ABSTRACT FROM AUTHOR]

Background and Objectives: It is of great importance to obtain information about the severity of ischemic damage and duration of testicular torsion for an effective treatment strategy. Nucleolar-organizing regions (NORs) are sites of the ribosomal genes composed of ribosomal DNA and proteins. Post-silver staining NORs are termed “AgNOR”. Since AgNORs clearly reveals the self-renewal potential of cells damaged in ischemic events, we performed the current study. Materials and Methods: The study was carried out in four groups as control, sham, early, and late T/D. In the surgical groups, testes were corrected after a 4-h ischemia period. Testicular tissue samples were taken on the third day after detorsion in group 1, 2, 3, and on the tenth day after detorsion in group 4. TUNEL and silver stainings were applied to all samples. Results: The differences were significant among the groups for both mean AgNOR number and total AgNOR area/total nuclear area (TAA/TNA). Moreover, the differences between control and early torsion-detorsion (T/D), between control and late T/D, between sham and early T/D, between sham and late T/D, and between early T/D and late were statistically significant for AgNOR amount. Furthermore, statistically significant differences among the groups for an average number of apoptotic cells per tubule and the percentage of apoptotic tubule values were detected. Discussion: The apoptotic index gives the ratio of cells that are damaged and will die in a programmed way and cells that remain intact, rather than show the viability of the returning testicle. However, by measuring cells that regenerate with AgNOR, we can show not only those that survive but also cells that can repair themselves. Conclusion: AgNOR proteins are usable for the early observation of ischemic injury levels. The amount of AgNOR protein can enlighten us about the extent of testicular damage after T/D treatment. It may also help the physician in the development of effective treatment strategies for cases.

Meloidae are commonly known as blister beetles, so called for the secretion of cantharidin, a toxic substance that causes irritation and blistering. There has been a recent increase in the interest of the cantharidin anticancer potential of this insect group. Cytogenetic and molecular data in this group are scarce. In this study, we performed a karyotype analysis of Hycleus scutellatus, an endemic species of the Iberian Peninsula. We determined its chromosome number, 2n = 20, as well as the presence of the X and Y sex chromosomes. In addition to a karyotype analysis, we carried out DAPI staining. By fluorescence in situ hybridization we mapped the rDNA clusters on 12 different chromosomes. Compared to others, this species shows an unusually high number of chromosomes carrying rDNA. This is one of the highest numbers of rDNA sites found in the Polyphaga suborder (Coleoptera). Additionally, we isolated a satellite DNA family (Hyscu-H), which was located within the pericentromeric regions of all chromosomes, including the sex chromosomes. The results suggest that Hyscu-H is likely to be one of the most abundant satellite DNA repeats in H. scutellatus.

Ribosomal DNA (rDNA) gene codes for 18S, 5.8S, and 28S rRNA form tandem repetitive clusters, which occupy distinct chromosomal loci called nucleolar organizer regions (NORs). The number and position of NORs on chromosomes are genetic characteristics of the species although within a cell, the NOR sizes can significantly vary due to loss or multiplication of rDNA copies. In the current study, we used mouse L929 fibroblasts, the aneuploid cells which differ in the FISH- and Ag-NOR numbers, to examine whether the parental NOR variability is inherited in clones. By statistical analysis, we showed that the cloned fibroblasts were able to restore the NOR numerical characteristics of the parental cells after long-term culturing. These results support the idea that mammalian cells may have mechanisms which control the number and activity of NORs at the population level. In L929 fibroblasts, we also regularly observed laterally asymmetry of FISH-NORs that evidenced in an unequal distribution of the mother rDNA copies between the daughter cells in mitosis. [ABSTRACT FROM AUTHOR]

Capsicum comprises 35 species of chili peppers and five of them are cultivated worldwide as spices or vegetables. Diploid karyotypes based in x = 12 and x = 13 are common in Capsicum and the constitutive heterochromatin (cHet) is of particular interest in the genus since it is largely variable, particularly its highly GC-rich fraction. However, the repetitive DNA components of this heterochromatic regions are unknown. Given the co-localization of rDNA loci with the CMA + DAPI– heterochromatic bands, we tested the hypothesis that the highly GC-rich cHet fraction is composed of the whole 18S-25S ribosomal DNA (rDNA) unit or some of its components. Here we report on a novel satellite for Capsicum and Solanaceae composed of the complete rDNA unit. We physically mapped six Capsicum derived specific 18S-25S rDNA probes that covered the entire span of the rDNA unit and analysed a Dra I restriction product on eight chromosomally different taxa of Capsicum, representative of the major phylogenetic clades of chili peppers. The co-localization of every gene and spacer probes of the 18S-25S rDNA unit suggest their structural function as a major repetitive component of the highly GC-rich cHet in Capsicum species with x = 12. In addition, analyses of the clones derived from restriction assays in C. pubescens suggested that the differential functional status of 18S-25S rDNA loci (nucleolar organizer regions -NORs- or cHet) in this species is related to a divergence in a short sequence upstream the regulatory transcription initiation site (TIS) of the intergenic spacer (IGS). The results here provided evidence that an rDNA mega satellite played a significant role in the evolution of the karyotype features of x = 12 Capsicum species. The finding of a mega satellite family derived from the whole rDNA unit is a novelty for plant genomes. [ABSTRACT FROM AUTHOR]

The first cytogenetic comparisons of five snapper species from Thailand were presented here. Renal cell samples were taken from blacktail snapper ( Lutjanus fulvus), five lined snapper ( L. quinquelineatus), dory snapper ( L. fulviflamma), brownstripe red snapper ( L. vitta), and mangrove red snapper ( L. argentimaculatus). The mitotic chromosome preparation was prepared directly from kidney cells. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosomes. The results exhibited that all five snapper species have the diploid chromosome numbers of 2 n = 48 and the fundamental numbers (NF) of 48. The presences of large, medium, and small telocentric chromosomes were 22-24-2, 24-20-4, 36-10-2, 28-16-4 and 36-10-2, respectively. The Ag- NORs banding technique provides the pair of nucleolar organizer regions (NORs) at subcentromeric region of the long arm of the respective telocentric chromosome pairs 9, 1, 3, 4 and 9. Their karyotype formulas is as follows: L. fulvus (2 n = 48): L + M + S , L. quinquelineatus (2 n = 48): L + M + S , L. fulviflamma (2 n = 48): Lt36 + Mt10 + St2, L. vitta (2 n = 48): L + M + S , and L. argentimaculatus (2 n = 48): L + M + S . [ABSTRACT FROM AUTHOR]

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

Background: ‘AgNOR’ represents Nucleolar Organiser Regions stained with silver which are related to cell proliferation rate and tumor malignant potential. The objective of this study was to evaluate the role of AgNOR in differentiating benign and precancerous lesions from cancerous lesions in both cervical smears and histology. Materials and Methods: This was a prospective study conducted at Manipal Teaching Hospital, from July 2005 to June 2007. Women of suspected cervical pathology and who underwent pap smears test followed by subsequent biopsy were included. There were 53 cases were included out of which 11 cases were of high grade squamous intraepithelial lesion and 12 cases of low grade squamous intraepithelial lesion, and 10 cases each of carcinoma, chronic cervicitis with and without squamous metaplasia. Results: In Low grade squamous intraepithelial lesion meanAgNOR dots was < (2.9 in pap smears and 1.9 in histology) in high grade lesion (3.45 in pap smears and 3.00 in histology). In carcinoma meanAgNOR dots was 5.18 and 4.05 in pap smears and histology respectively. Subjective AgNOR Pattern Assessment in pap smears and in histology was increasing with significant difference from intraepithelial lesions to carcinoma. Conclusion: In cervical pathology, the number and shape of AgNOR dots change from benign to precancerous to malignant tumors. Similarly, AgNOR Pattern Assessment is useful in differentiating benign to intraepithelial lesions to carcinoma cases. DOI: http://dx.doi.org/10.3126/jpn.v2i3.6017 JPN 2012; 2(3): 180-185

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.

OBJECTIVE: The purposes of this study were to histologically assess different types of oral squamous cell carcinoma and the silver-binding nucleolar organizer region (AgNOR) morphology in neoplastic cells, as well as to quantify the number of AgNORs in each type of carcinoma in order to relate AgNOR count and histologic grading. MATERIAL AND METHODS: Twenty-eight cases of oral squamous cell carcinoma were divided into 4 groups, namely well-differentiated, moderately differentiated, poorly differentiated, and undifferentiated. For NOR study, 3-µm-thick sections were stained with 50% aqueous silver nitrate solution. The predominant microscopic pattern of NORs was determined. Quantitative analyses of NORs were obtained of all cells present on each histological field using a 0.025 mm² eyepiece graticule. Different histological fields were analyzed until the total number of NORs was 120 cells for each tumor. Kruskall-Wallis test was applied to compare the groups of sample data at a significance level of p=0.05. RESULTS: The mean number of AgNORs per nucleus was 3.20 for the well-differentiated group, 5.33 for the moderately differentiated one, 8.27 for the poorly differentiated one, and 10.08 for the undifferentiated one. AgNOR count was significantly different (p

Background and Objective: Argyrophilic nucleolar organizer regions (AgNORs) have found widespread application in the past, especially in tumor histopathology. This study was undertaken to evaluate the significance of various AgNOR parameters and to assess their role in differentiating hyperplastic, premalignant, and malignant lesions. Materials and Methods: The study sample consisted of archival biopsy specimens of ten squamous cell carcinomas, ten premalignant lesions, and five inflammatory lesions. Two biopsies from normal mucosa acted as control. AgNORs were assessed both quantitatively and qualitatively. The data were analyzed using Student′s independent t-test, one-way analysis of variance (ANOVA), and multiple range test (Tukey-HSD). Results: Quantitatively significant difference existed in the number of AgNORs between the normal mucosa, inflammatory lesions, and carcinomas, but the premalignant lesions failed to differ significantly from the normal mucosa. The number of AgNORs was found to be related to epithelial proliferation. Qualitatively, in terms of size, shape, and pattern of distribution, the normal mucosa and inflammatory lesion were alike, but the premalignant and malignant lesions differed significantly from the normal, with a marked degree of AgNOR pleomorphism being observed in carcinomas. Conclusions: AgNOR quantity is strictly proportional to the proliferative activity of the cell and does not necessarily indicate malignancy. It is the qualitative characteristics of AgNOR that help to differentiate hyperplastic, premalignant, and malignant lesions.

BACKGROUND AND OBJECTIVE: Nowadays, besides the ordinary staining, a variety of cell markers and immunohistochemistry methods are incorporated for distinction between neoplasms. But in the current situation, due to the high cost of most of these methods, cheaper and simpler way like silver nitrate staining should be sought for analyzing the nucleolar organizer dots. Therefore, this study was conducted to evaluate the distinction capability of silver nitrate within the benign and malignant neoplasms of the salivary glands.METHODS: Silver nitrate staining was carried out for nucleolar organizer regions in 22 cases of the most common benign neoplasms of the salivary glands, namely pleomorphic adenoma, and 22 cases of common malignant neoplasms of salivary glands, consisting of 11 adenoid cystic carcinoma and 11 mucoepidermoid carcinoma cases. Twenty-two cases of normal salivary glands of the peripheral regions of the same samples were analyzed.FINDINGS: The mean dots occurrences for normal salivary glands, pleomorphic adenoma, adenoid cystic carcinoma and mucoepidermoid carcinoma were 1.67±0.2, 2.32±0.39, 3.92±1.11 and 3.25±0.78 (for malignancies was 3.58±1), respectively. There were significant differences among benign and malignant, malignant and normal, and benign and normal groups (p

Background and Aim: A strong causal relationship exists between cigarette smoking and development of oral squamous cell carcinoma, so oral screening using exfoliative cytology has been recommended to facilitate the early diagnosis of cellular alterations in oral mucosa and silver staining (AgNOR technique) has been proven to be of value in the detection of incipient cellular alterations. The purpose of this study was to compare the argyrophilic nucleolar regions (AgNORs) count of cells collected from normal mucosa of cigarette smokers with that obtained from non- smokers. Materials and Methods: In this cross-sectional study, cytologic smears of normal tongue, buccal mucosa and floor of the mouth from 19 smokers and 19 non- smokers were stained for AgNORs. The AgNORs count was established on 100 cells. The count value of groups were compared and analyzed using the Levens, Paired T, Student and Factorial tests. Using P

Objective: Nucleolar organizer regions are loops of DNA containing ribosomal RNA genes and presumably are associated with ribosomal RNA activity, protein synthesis, and cell proliferation. Argyrophilic nucleolar organizer region (AgNOR) count has been suggested as an objective method in differentiating dysplastic lesions from non-dysplastic lesions.Materials and Methods: This descriptive study was done on archival paraffin blocks (n = 60), consisting of 10 normal human oral epithelium, 22 cases of non-dysplastic leukoplakia (NDLK), and 28 cases of dysplastic leukoplakia (DLK). The AgNORs were counted with the aid of a manual using conventional light microscopy and photographs of the same were taken and analyzed using Image Pro Express 6.0 (Media Cybernetic Inc., USA) for windows.Results: The mean AgNOR count per nucleus was found to be higher in patients with DLK as compared to NDLK and controls using both manual counting and image analysis method and on comparing both the techniques, image analysis provide a more accurate reflection of AgNOR counts than manual counting.Conclusion: To conclude, reliability of computerized image technique of AgNOR count is the most appropriate marker to differentiate between dysplastic and NDLK. Computer-assisted image analysis system was found to be an effective tool in achieving high reproducibility as compare to manual. [ABSTRACT FROM AUTHOR]

Argyrophilic proteins associated with nucleolar organizer regions (Ag-NOR proteins) and Ki-67 antigen were analyzed in 118 samples of squamous cell carcinoma of the lungs. Tumors with low and high content of Ag-NOR proteins and Ki-67 index were selected. It was found that the content of Ag-NOR proteins correlated with some clinical and morphological parameters (indexes T and N, tumor size less and more that 3 cm, stage of the disease, and tumor differentiation degree) and survival rate. High survival was associated with low content of Ag-NOR proteins and Ki-67 index and low survival correlated with high content of Ag-NOR proteins and Ki-67 index, while intermediate survival was associated with opposite values of Ag-NOR protein content and Ki-67 index. The tumor size, parameter N, and the content of Ag-NOR proteins had independent effects on patient's survival. In patients with squamous cell carcinoma of the lung without metastases in lymph nodes, survival correlated with the content of Ag-NOR proteins; in patients without metastases, survival correlated with tumor size. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: To carry out a quantitative and qualitative assessment of AgNORs (Silver staining Nucleolar Organizer Regions) in normal odontogenic epithelium and in odontogenic cysts. Methods: Twenty five paraffin embedded tissue sections of normal odontogenic epithelium and odontogenic cysts. From each block, 2 sections were cut. One set of sections was stained by Ehrlich's hematoxylin and eosin for histologic diagnosis. The other set was stained by the improved method of silver staining technique for nucleolar organizing regions. In each of the sections 100 individual supra basal cells were examined from the representative areas of the epithelium. The methodical and systematic quantification of AgNORs was carried out under 100X oil immersion objective. Results: The mean value of large AgNOR count found in the nucleus of normal odontogenic epithelium was 1.44 and small AgNOR count was 0.69 whereas the mean value of large AgNOR count in the nucleus of odontogenic cyst epithelium was 1.02 and small AgNOR count was 2.81. In normal odontogenic epithelium, the mean of total AgNOR count was 2.13(+/-0.1) and in odontogenic cyst were 3.84(+/- 0.63). Conclusions: It can be presumed that the increase in the number of AgNOR could be correlated with the proliferative change in odontogenic epithelium. [ABSTRACT FROM AUTHOR]

Abstract: Alticinae has the greatest amount of biodiversity among the Chrysomelidae, with 40,000 described species, only 290 of which have been analyzed cytogenetically. The majority of studies refer to conventional staining and few species have been analyzed or have responded to differential staining methods. The aim of the present study was to describe an 18S rDNA probe for Alticinae and the location of this cluster in species of the Omophoita genus. The fragment of approximately 750bp obtained through a PCR (Polymerase Chain Reaction) amplification reaction with specific oligonucleotides to 18S rDNA was cloned and denominated pTZ_Ooct_18Sp and then submitted to automatic sequencing. The alignment of the sequences obtained through the sequencing of the clones generated a consensus sequence of 722bp for Omophoita octoguttata with 98% homology with other species of Alticinae. The analysis of mitotic cells of O. octoguttata and Omophoita magniguttis submitted to fluorescent in situ hybridization (FISH) with the 18S rDNA probe revealed that the ribosomal genes are located in 6th pair. O. magniguttis also has a second labeled pair. Omophoita personata exhibited nucleolar organizer regions associated to one autosome pair. The analysis of meiotic cells submitted to FISH revealed one labeled bivalent in metaphase I in O. octoguttata and O. personata and in one chromosome in metaphase II in O. octoguttata. FISH data suggest a conserved pattern in the species analyzed and an apomorphy of O. magniguttis karyotype. The rDNA 18S probe could be considered an important marker to evidence the karyotypic differentiation, not observed with conventional methodologies, in species considered karyotypically conserved and uniform. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to determine the diagnostic accuracy of routine Papanicolaou stain (PAP) and Silver stained Nucleolar Organizer Regions (AgNOR) staining in brush biopsies taken from suspected oral lesions for early detection of oral cancer. Materials and Methods:Brush biopsies were collected from macroscopically suspicious lesions of the oral cavity of 34 patients and 10 normal-aged and sex-matched controls. The numbers of AgNORs were counted in 100 squamous epithelial cell nuclei per slide after silver staining of the smears (Ploton's one-step method). Results:Sensitivity and specificity of PAP analysis in the oral smears for detection of oral cancer and normal cells was 91.176% and 100%. The positive and negative prediction values were 100% and 76.92%, respectively. Sensitivity and specificity of AgNOR analysis in the oral smears for detection of oral cancer and normal cells was 100%. The positive and negative prediction values were 100% each. Conclusion: Based on the above facts, we conclude that brush biopsy in conjunction with AgNOR staining is an easily practicable, non-invasive, safe and accurate screening method for the detection of macroscopically' suspicious oral cancerous lesions. Because of its simple technique and high reliability for cellular proliferation, AgNOR staining in brush smears can be used as an adjunct to other routine cytological diagnoses for the early detection of oral cancer. However, further investigations with more number of study samples will be needed to establish this correlation beyond doubt. [ABSTRACT FROM AUTHOR]

This study describes the karyotype of Noctilio albiventris from the northern Pantanal region of central Brazil and discusses its taxonomic applications. Cytogenetic analysis of mitotic metaphase chromosomes from bone marrow preparations of 12 specimens shows that a diploid number (2n) of 34, an autosomal fundamental (FNa) of 62, and respective submetacentric and acrocentic X and Y chromosomes comprise the trypsin-Giemsa (G)-banded karyotype. Chromosome pair 12 demonstrated active nucleolar organizer regions (NOR) with secondary constrictions. Findings also revealed a constitutive heterochromatin distribution patterns in the pericentrometric regions of all autosomes and in the X chromosomes.

Objective. Evaluate the relationships between AgNORs polymorphisms and squamous intraepithelial lesions (SIL) and squamous cell carcinoma (SCC) with HPV infection. Materials and methods. A study was carried out on sixty women from the state of Guerrero, Mexico. HPV detection was performed by PCR. AgNORs were identified by argentic impregnation. One hundred cells per slide were counted and classified according to the polymorphism of AgNORs dots; typical (spherical) and atypical (large, kidney-shaped and clustered). Results. A total of 100% of the cases were positive for HPV infection. Nine different high-risk HPV genotypes were found, type16 was the most common (48.6%). The AgNORs showed a significant decrease in spherical shape according to neoplastic development. The three atypical shapes showed a significant increase in SIL and SCC (p-trend<0.001). Conclusions. AgNORs polymorphism rises progressively according to the grade of histological lesions that can be useful as a prognosis for progression of SCC. [ABSTRACT FROM AUTHOR]

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Abstract: Nucleolar organizer regions (NORs) were assessed in 27 women affected by uterine leiomyoma. Tissue samples obtained during surgery were silver-stained according to the method of Ploton et al. The assessed parameters were as follows: the number of argyrophylic nucleolar organizer regions (AgNORs) per nucleus, single AgNOR area, AgNOR intranuclear distribution, and AgNOR coefficient. The parameters were assessed quantitatively. It was found that the AgNOR coefficient was higher in uterine leiomyoma compared to the normal smooth muscle cells. The development of leiomyoma is associated with a marked decrease in myocyte nucleolar area, which accounts for 30% of the nucleus in the normal myometrium. With the comparable AgNOR number in the single nucleus, there were no differences in the single AgNOR granule area (1.21μm2±0.047 and 1.11μm2±0.025 in normal myometrium and in leiomyoma, respectively). In the normal myometrium, there was a positive correlation between nuclear area and the single AgNOR granule area, as well as between the AgNOR coefficient and the single AgNOR granule area. There was also a negative correlation between the number of granules per nucleus and their central and peripheral intranuclear distribution. The development of leiomyoma was associated with loss of all correlations observed in the control group. [Copyright &y& Elsevier]

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder in middle and late age. Ribosomal RNA (rRNA) genes are located in the nucleolus (nucleolar organizer regions = NORs). There are increased deposits of β-amyloid protein in the brains of the patients with AD and aged individuals with Down’s syndrome (DS). The β-amyloid gene is located in the acrocentric chromosome 21 that is responsible for rRNA synthesis. Therefore, it is possible that there is a relationship between ribosomal genes and AD. Objective: To investigate the activities of ribosomal genes of AD patients by comparing the activities of NORs in AD patients and healthy controls with the silver-staining method. Methods: NOR surface/the total nucleus surface proportions in interphase nuclei, and silver stainability and satellite association (SA) of acrocentric chromosomes in the metaphases of cultivated lymphocytes of 20 AD patients and 20 healthy controls (10 elderly and 10 young) were evaluated. Results: A decrease in NOR surface/total nucleus surface proportions has been observed in the interphase nucleus of AD patients when compared with elderly controls (p = 0.035). When compared with the sizes of Ag+ segments of acrocentric chromosomes of AD patients and control groups, the Ag-staining size 1 of the chromosome 22 of AD patients was found to be more increased than that of the young controls (p = 0.018). There was no statistically significant difference between AD patients and control groups regarding the number of Ag+ acrocentric chromosomes, Ag+ chromosome 21 and SA frequency (p > 0.05). It has been found that there is only a slight increase in the total number of chromosomes in SA in AD patients when compared with elderly controls (p = 0.05). Conclusion: The decrease in NOR surface/total nucleus surface proportions of AD patients may indicate a reduction in the activity of the ribosomal genes of these patients. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Reducing body myopathy is a rare muscle disease defined by abnormal inclusions in affected muscle fibers that can be stained with menadione-nitroblue tetrazolium. The origin of these inclusions has not been determined. Here we show that reducing bodies bear characteristics of nucleoli. Ultrastructurally, muscle biopsy specimens of a patient with adult-onset reducing body myopathy showed granular structures of reducing bodies with features similar to the granules of nucleoli, which consisted of pre-ribosomes. In addition, reducing bodies were positive for histochemistry of argyrophilic nucleolar organizer regions (a method for detecting the areas where ribosomal RNA is actively transcribed in the nucleolus), and for antibodies against nucleoli and nuclear ribonucleoprotein. The current findings suggest that reducing bodies contain pre-ribosomes and their associated proteins of the nucleolus and that formation of reducing bodies may result from defects of processing and assembly of ribosomes. [ABSTRACT FROM AUTHOR]

Metaphase nucleolar organizer region (NOR) activity was studied in mouse lines selectively bred for high analgesia (HA) and for low analgesia (LA) induced by 3-min swimming in 20°C water. Apart from pain-related traits, HA mice also manifest, as compared to the LA line, higher emotionality in certain behavioral tests and are less capable of coping with the hypothermic challenge of swimming in cold water, in addition to being more susceptible to the mutagenic effect of whole-body γ-radiation and mitomycin C injection. We here compared NOR activity in HA and LA mice. A statistically significant difference (p ≤ .01) was detected in mean silver-stained nucleolar number/cell between the HA and LA lines, being lower for HA mice. We propose that the breeding strategy, along with the differentiation of stress-related phenomena, has altered the activity of genes coding rRNA and that this activity is important in controlling DNA repair in each line. It is concluded that quantitative studies of nucleolar changes may be useful in evaluating the biological reactivity to stress stimuli. [ABSTRACT FROM AUTHOR]

We investigated the characteristics of morphology, DNA synthesis and argyrophilic nucleolar organizer regions (AgNORs) on murine Dunn osteosarcoma cells in response to heat (42 °C, 1 h) or dibutyryl cyclic adenosine 3′,5′-monophosphate (Bt2cAMP). The cell morphology changes to a fibroblast-like appearance with long and thin protoplastic processes with the reduction of DNA synthesis by heat. It is closely similar to a response by Bt2cAMP. In the presence of 3 mM Bt2cAMP, the mean number of AgNORs was significantly decreased in 48 h compared with the untreated group. It was increased conversely by heat. Among these responsive cells, we can also find many cells stained without discrimination by the use of AgNORs staining. The present study provides a new clue to support differentiation of osteosarcoma cells from the viewpoint of hyperthermia in vitro. [Copyright &y& Elsevier]

Human ribosomal gene repeats are distributed among five nucleolar organizer regions (NORs) on the p arms of acrocentric chromosomes. On exit from mitosis, nucleoli form around individual active NORs. As cells progress through the cycle, these mini-nucleoli fuse to form large nucleoli incorporating multiple NORs. It is generally assumed that nucleolar incorporation of individual NORs is dependent on ribosomal gene transcription. To test this assumption, we determined the nuclear location of individual human acrocentric chromosomes, and their associated NORs, in mouse> human cell hybrids. Human ribosomal genes are transcriptionally silent in this context. Combined immunofluorescence and in situ hybridization (immuno-FISH) on three-dimensional preserved nuclei showed that human acrocentric chromosomes associate with hybrid cell nucleoli. Analysis of purified nucleoli demonstrated that human and mouse NORs are equally likely to be within a hybrid cell nucleolus. This is supported further by the observation that murine upstream binding factor can associate with human NORs. Incorporation of silent NORs into mature nucleoli raises interesting issues concerning the maintenance of the activity status of individual NORs. [ABSTRACT FROM AUTHOR]

Nucleolar organizer regions are segments of DNA associated with argyrophilic proteins (AgNORs). Our previous findings showed that the number, the area, and the intranuclear localization of AgNOR dots differ according to tumor aggressiveness and to the hormone-immunopositivity of pituitary adenomas. Proliferating cell nuclear antigen (PCNA) is a nuclear protein, whose expression is correlated with cell proliferation. The aim of the present paper was to examine PCNA-labeling indexes in pituitary adenomas and to correlate them with AgNOR dots in various immunohistochemical types of the tumors. Histological slides from 32 pituitary tumors and one normal pituitary were silver-stained and analyzed with a computerized system for microscopic image analysis. We found that the percentage of PCNA-positive cells did not differ significantly among examined groups of monohormonal adenomas. However, tumors immunopositive for α-subunit (α-SU) showed a significantly higher ( p<0.05) PCNA index than adenomas immunonegative for that unit. PCNA index in recurrent tumors was significantly higher than in primary adenomas. There was a moderate positive correlation between the PCNA index and the mean area of AgNOR dots and a similar correlation between the PCNA index and the area of the biggest dot in the nucleus. The obtained results reveal that the PCNA indexes and estimated parameters of AgNOR dots differ according to tumor aggressiveness. [ABSTRACT FROM AUTHOR]

Nucleolar organizer regions (NORs) are segments of DNA, encoding for ribosomal RNA. They are associated with argyrophilic proteins and, thus, they can be localized through silver staining. A correlation has been shown between the number, the size, or the intranuclear localization of AgNORs, and the proliferative activity of cells. The aim of this study was to examine numerous features of AgNORs in pituitary adenomas and to relate them to immunohistochemical typing of tumor. Histologic slides from 32 pituitary tumors and one normal pituitary were silver-stained and analyzed with a computerized system for microscopic image analysis, supported by an AgNORmeter95 program. All the tumors were also immunocyto chemically characterized. We have found that gonadotropinomas, when compared with plurihormonal adenomas, revealed a lower proportion of nuclei with a single AgNOR and a higher percentage of marginal dots. Recurrent adenomas, when compared with primary adenomas, showed a higher proportion of nuclei with three AgNOR dots, a larger total area of dots in the nuclei, and a higher standard deviation of the AgNOR dot area in the nucleus. Adenomas immunopositive for prolactin, when compared with immunonegative ones, showed a larger mean area of the AgNOR dot, a larger area of the biggest dot in the nucleus, and a higher proportion of nuclei within a single dot. These results suggest that the estimated parameters of AgNOR dots differ according to tumor aggressiveness and to the hormone immunopositivity of pituitary adenomas. [ABSTRACT FROM AUTHOR]

The possibility of detection of incipient cellular alterations is central to early diagnosis and to clinician's capacity to discriminate between samples that appear similar on routine preparations. We examined the value of silver-stained nucleolar organizer regions (AgNOR) in detecting radio-induced alterations in a model of squamous epithelium biologically similar to oral mucosa. Morphometry of AgNOR has been proven to be of value in the detection of incipient cellular alterations. This method allows for the quantitative evaluation of lesions induced by high doses of radiation long before they become apparent in routine preparations. We herein examine the capacity of AgNOR to reveal the response to low doses of radiation, closer to the therapeutic or accidental dose to which the epithelium of oral mucosa may be exposed. [ABSTRACT FROM AUTHOR]

The evolution of the pattern of nucleolar organiser regions (AgNORs) in circulating lymphocytes during the stable phase and after chemotherapy in CLL was analysed. Peripheral blood smears were stained by the AgNOR technique at diagnosis, during observation follow-up in stable phase, or at the beginning and at the end of chemotherapy in patients with progressive disease. The changes in the AgNOR pattern were compared with those of TTM used as a tumour burden parameter. Among 52 cases that entered the study, 29 were in stable phase and 23 had progressive disease and received chemotherapy. During stable phase, the AgNORs as well as TTM remained constant. In treated patients, the relative reduction of tumour mass was correlated with a decrease in the percentage of lymphocytes containing one AgNOR cluster. The percentage of cells with one compact nucleolus before chemotherapy was inversely correlated with the relative amount of tumor reduction after treatment. We conclude that the AgNOR pattern in CLL describes the cell kinetic changes during the evolution of the disease and is a prognostic factor for tumor reduction after treatment. [ABSTRACT FROM AUTHOR]

We report on a major update to the animal rDNA loci database, which now contains cytogenetic information for 45S and 5S rDNA loci in more than 2600 and 1000 species, respectively. The data analyses show the following: (i) A high variability in 5S and 45S loci numbers, with both showing 50-fold or higher variability. However, karyotypes with an extremely high number of loci were rare, and medians generally converged to two 5S sites and two 45S rDNA sites per diploid genome. No relationship was observed between the number of 5S and 45S loci. (ii) The position of 45S rDNA on sex chromosomes was relatively frequent in some groups, particularly in arthropods (14% of karyotypes). Furthermore, 45S rDNA was almost exclusively located in microchromosomes when these were present (in birds and reptiles). (iii) The proportion of active NORs (positively stained with silver staining methods) progressively decreased with an increasing number of 45S rDNA loci, and karyotypes with more than 12 loci showed, on average, less than 40% of active loci. In conclusion, the updated version of the database provides some new insights into the organization of rRNA genes in chromosomes. We expect that its updated content will be useful for taxonomists, comparative cytogeneticists, and evolutionary biologists. [ABSTRACT FROM AUTHOR]

Silver staining was used to estimate the expression of nucleolar organizing regions (NORs), and in-situ hybridization (ISH) with rDNA probes was used to estimate the relative content of rDNA in each NOR in chromosome preparations of the dormouse, Eliomys quercinus, a species with two NOR-bearing chromosome pairs. Both types of signals were sequentially investigated on every NOR by using an Ag-ISH sequential staining method, which made it possible to demonstrate that the relative amount of rDNA in a NOR in comparison with the other chromosomes of the complement determines its level of expression and its likelihood of becoming active, regardless of whether the NORs are homologous or not. We suggest that the NORs in each cell are activated in accordance with an established hierarchy. We propose a two-stage model to relate NOR structure and function, which is consistent with these results and with current knowledge on the molecular regulation of NOR transcription. [ABSTRACT FROM AUTHOR]