Relationship between interphase AgNOR distribution and nucleolar size in cancer cells

Summary We have studied the relationship between interphase nucleolar organizer region (NOR) distribution and nucleolar size in cancer cells at light-microscopical level. Thirteen cases of formalin-fixed bladder cancer and fifteen cases of methacarn-fixed tumours of different origin were used. Nucleoli of the former cases were stained by Phloxine B and of the latter by Toluidine Blue. Selective visualization of interphase NORs was obtained by carrying out the one-step silver staining reaction for AgNOR proteins (Plotonet al., 1986). The area occupied by Phloxine B- or Toluidine Blue-stained nucleoli and interphase silver-stained NORs was measured by means of an automated image analyser. Both in bladder cancers and in the other tumour lesions nucleolar and interphase AgNOR areas were linearly related (r=0.95 and r=0.96, respectively,P<0.001). The close relationship between the area of nucleoli and that of silver-stained nucleolar structures was maintained even if the silver-staining procedure was prolonged beyond the optimal time length for selective interphase NOR staining. In the latter case, however, single interphase AgNORs were no longet visible within the nucleolar body which was, in fact, homogeneously stained. These data indicate that evaluation of the interphase AgNOR area has the same relevance, in tumour pathology, as whole nucleolar size measurement.     

肿瘤核仁形成区形态定量诊断的误差及规范化分析

本文采用包括自动图象分析技术在内的ＡｇＮＯＲ形态定量学方法,以大肠肿瘤为模型,进行了ＡｇＮＯＲ定量形态学研究的误差分析,以探讨肿瘤ＡｇＮＯＲ定量诊断规范化的可能。结果表明,染色条件、视场目标选择和细胞计数量是引起ＡｇＮＯＲ定量诊断的主要误差;恒定染色环境,正确选择欲测细胞及测定足够量的细胞是使ＡｇＮＯＲ形态定量诊断规范化的途径。     

Prognostic value of nucleolar organizer regions in neuroendocrine tumours of the lung

The value of the number and size of the nucleolar organizer regions (NORs) as prognostic indicators in human neuroendocrine lung tumours was evaluated in a quantitative study of 57 cases, including 33 small cell carcinomas (SCLCs), 9 well-differentiated neuroendocrine carcinomas (WDNECs) and 15 classic carcinoids. NORs were visualized on paraffin sections by an argyrophilic technique (AgNOR) and measured by automatic image analysis. In each case, the mean number and area of AgNORs were evaluated; the results were compared with clinical follow-up and survival. AgNOR values for both number and area were significantly higher in SCLCs than in WDNECs and carcinoids. WDNECs had insignificantly higher AgNOR values than carcinoids. Among SCLCs, AgNOR values of the oat cell subtype and the intermediate cell subtype did not differ significantly. Regardless of the histological tumour type, AgNOR values strongly correlated with prognosis, with more and larger AgNORs indicating a more progressive clinical course. In the present study we demonstrate for the first time that the biological behaviour of neuroendocrine lung tumours is correlated with the number and size of AgNORs. Thus the measurement of AgNORs may serve as an additional prognostic indicator in these neoplasms, particularly in the separation of SCLCs from WDNECs with a more favourable prognosis.     

Quantitative AgNOR assessment of cancer cell populations in undifferentiated nasopharyngeal carcinoma

OBJECTIVE: To evaluate the proliferative activity of cancer cell populations in undifferentiated nasopharyngeal carcinoma (NPC) by quantitative assessment of argyrophilic nucleolar organizer regions (AgNOR) proteins. STUDY DESIGN: Silver-staining of NORs was applied to 18 paraffin sections of undifferentiated NPC containing a vesicular nuclear cancer cell population (VNCC) and spindle-shaped cancer cell population (SSCC). Various features of AgNORs in these two cell populations were analyzed by image cytometry and compared. RESULTS: Mean AgNOR count, mean AgNOR area and AgNOR area-count ratio of VNCC were statistically significantly higher than those of SSCC, while no significant difference was found in AgNOR area/nuclear area ratio between the two cancer cell populations. CONCLUSION: The different cancer cell populations with their distinct morphologic characteristics in undifferentiated NPC have different proliferative activity. The relationship between proliferative heterogeneity of cancer cell populations in undifferentiated NPC and its sensitivity to radiotherapy awaits further study.     

Argyrophilic nucleolar organizer regions (AgNORs) in interphases and metaphases of normal and neoplastic gill cells of Macoma balthica (Bivalvia: Tellinidae) from the Gulf of Gdansk, Baltic Sea

Chromosome analysis of gill cells of different populations of Macoma balthica (L.) from the Bay of Gdansk (Baltic Sea) revealed 2 clam categories, 1 with neoplastic features and 1 without. Silver-staining was performed on interphase and metaphase cells of both categories. The mean argyrophilic nucleolar organizer region (AgNOR) count per abnormal interphase cell was significantly higher than in normal interphase cells. Normal silver-stained metaphases had 3 nucleolar organizer region (NOR) chromosome phenotypes. The location of the NORs in the most frequent phenotype (55.6% in 54 metaphases scored) was interstitial on the largest metacentric chromosome pair, Pair No. 1. Abnormal silver-stained metaphases had a higher number of active NOR sites. Different phenotypes were observed (frequency greater than 10% for 67 metaphases scored); 2 were similar to those in normal metaphases and 5 were ectopic. The higher activity of AgNORs observed in abnormal cells confirmed the diagnosis of malignant neoplasia.     

AgNOR count in resting cells (resting NOR) is a new prognostic marker in invasive bladder tumor.

PURPOSE: We have previously demonstrated that the AgNOR count in proliferating cells is a predictor of tumor recurrence in superficial bladder tumor (J. Urol. 162 (1999), 63-68). In the present study, we evaluate the type of AgNOR associated with cell cycles as a prognostic factor in invasive bladder tumor using a double staining technique employing both AgNOR and MIB-1 labelling. MATERIALS AND METHODS: Forty-four paraffin sections of invasive bladder tumors were stained simultaneously with AgNOR and MIB-1. The number of AgNORs in proliferating (MIB-1 positive) or resting (MIB-1 negative) cells were counted from a total of 100 nuclei. Correlations between MIB-1 associated AgNOR count and clinicopathological parameters were statistically analyzed. RESULTS: The AgNOR count in proliferating cells (proliferating NOR) was significantly higher than that in resting cells (resting NOR) (p<0.01). The resting NOR in tumors with distant metastases was significantly higher than that in tumors without metastases (p<0.05). Patients with a low resting NOR tumor had a better prognosis than those with a high resting NOR tumor, whereas the proliferating NOR was not associated with survival. Survival analysis revealed that the resting NOR was the most powerful prognostic marker in patients with invasive bladder tumor (p<0.05). CONCLUSIONS: Resting NOR had a predictive value in the prognosis of patients with invasive bladder tumor.     

Nonrandom distribution of metaphase AgNOR staining patterns on human acrocentric chromosomes.

The metaphase nucleolar organizer regions (NORs) contain ribosomal genes associated with proteins such as upstream binding factor (UBF) and RNA polymerase I (RPI). These genes are clustered in 10 loci of the human acrocentric chromosomes (13, 14, 15, 21, and 22). Some NOR-associated proteins, termed AgNOR proteins, can be specifically stained by silver. In this study we took advantage of technical advances in digital imaging, image restoration techniques, and factorial correspondence analysis (FCA) to study the different AgNOR staining patterns of metaphase chromosomes in human lymphocytes. Three predominant patterns could be distinguished: pair (47%), stick-like (28%), and unstained (18%) structures. By studying the frequency of occurrence of each pattern on different chromosomes, two groups could be defined. Chromosomes 13, 14, and 21 carried predominantly pair or stick-like AgNOR structures, whereas chromosomes 15 and 22 mainly carried pair AgNOR structures or remained unstained. We suggest that the different AgNOR shapes reflect both the number of ribosomal genes carried by each chromosome and the differential recruitment of active ribosomal genes in each NOR cluster. This is the first study showing a nonrandom distribution of AgNOR shape among acrocentric chromosomes.     

鼻咽癌及癌旁上皮细胞的AgNORs定量分析及其生物学意义

目的通过鼻咽癌及癌旁上皮的细胞核仁组成区蛋白(NORs)图像定量分析,评价其反映细胞群体增生能力及分化程度等生物学意义。方法对70例鼻咽癌石蜡切片进行银染(AgNORs),应用CAS200图像分析仪分别测定29例癌旁正常腺上皮、19例增生／异型增生柱状上皮、10例增生／异型增生鳞状上皮、54例分化性非角化性癌和16例未分化癌的细胞群体AgNORs参数值并作比较分析;结果每核AgNOR计数、每核AgNOR面积和平均AgNOR面积／粒从正常腺上皮至增生／异型增生柱状上皮至分化性非角化性癌或未分化癌呈现显增加,平均核面积、每核AgNOR面积和平均AgNOR面积／粒从正常腺上皮至增生／异型增生鳞状上皮至未分化癌呈现显增加,差异均有显性,但增生／异型增生鳞状上皮与分化性非角化性癌的AgNOR数值差异没有显差异;与分化性非角化性癌比较,未分化癌的平均核面积、每核AgNOR面积和平均AgNOR面积／粒显增加。结论．AgNORs形态定量分析反映了鼻咽癌及癌旁不同类型鼻咽上皮的细胞增生活性和组织细胞分化程度,但不能反映细胞是否恶性转化;不同组织类型鼻咽癌细胞存在增殖能力的差异,其增生差异程度可能是影响病人对放射线治疗敏感性及其预后的重要因素之一。     

Proliferative activity of the thyroid oxyphilic tumor cells estimated by means of quantitative analysis of silver stained nucleolar organizer regions (AgNORs)

Promising results of studies on different neoplasms, by means of morphometric analysis of argyrophilic nucleolar organizer regions (AgNORs), known as proliferative activity marker, made us undertake an attempt to evaluate of proliferative activity in Hürthle Cell Tumors using the same technique. 78 cases including 20 Hürthle Cell Carcinomas (HCC), 32 Hürthle Cell Adenomas (HCA) and 26 hyperplastic nodules with Hürthle Cell Metaplasia (HCM), diagnosed in the Department of Clinical Pathology, Medical Academy of Bialystok in the years 1990-2000, were subjected to analysis. For visualization of the NORs we used the D. Ploton et al. technique. Mean AgNOR count and NORDS (NOR distribution score--the percentage of nuclei with at least 5 argyrophilic granules) were estimated in each case in 100 randomly chosen nuclei. Non-parametric Mann-Whitney U-test was applied to determine statistically significant differences. RESULTS: Mean AgNoRs counts and NORDS values were 5.1 and 52%, 3.4 and 26%, 2.5 and 7% in HCC, HCA and HCM respectively. Statistically significant differences were found between AgNORs counts in carcinomas and adenomas (p<0.01), HCCs and HCMs (p<0.005) and betwveen NORDS in all groups (p<0.001).     

Is there any relationship between decreased AgNOR protein synthesis and human hair loss?

Argyrophilic nucleolar organizing region associated proteins (AgNORs) play roles in cell proliferation and a variety of diseases. We attempted to determine whether decreased NOR protein synthesis causes human hair loss. We studied 21 healthy males who suffered hair loss on the frontal/vertex portion of the head. Hair root cells from normal and hair loss sites were stained for AgNOR. One hundred nuclei per site were evaluated and the AgNOR number and NORa/TNa proportions of individual cells were determined using a computer program. The cells from normal sites had significantly higher AgNOR counts than those from hair loss sites. Also, the cells from the normal sites had significantly higher NORa/TNa than cells from the hair loss sites. In the normal sites, the cells demonstrated more NOR protein synthesis than cells in hair loss sites. Therefore, decreased NOR protein synthesis appears to be related to hair loss in humans.     

Nuclear morphometry and AgNOR quantification: computerized image analysis on ovarian mucinous tumor imprints

OBJECTIVE: To determine the morphometric characteristics of nuclei and silver-stained nucleolar organizer regions (AgNORs) on cytologic imprints and their value in differential cytodiagnosis of benign, atypical proliferative (borderline) and malignant ovarian mucinous tumors. STUDY DESIGN: Forty-six mucinous ovarian tumor imprints (16 benign, 15 borderline, 15 malignant), were analyzed. Nuclear area, outline, "shape factor" and "form factor" were measured on Papanicolaou-stained smears. AgNOR quantification included 7 variables related to the number and area of single, cluster, total and relative AgNOR content per nucleus and the size distribution of AgNORs. RESULTS: Nuclear area and shape factor allowed distinguishing borderline and malignant tumors. The nuclear area in benign tumors was larger than that in borderline tumors; malignant tumors had the highest values. Single and cluster AgNORs were statistically significantly different in borderline tumors compared with malignant tumors, except for the cluster AgNOR area. The total AgNOR area, number and relative area increased from benign through malignant tumors, with statistically significant differences among all groups. By AgNOR size distribution, small AgNORs discriminate malignant from borderline and benign tumors. CONCLUSION: Combining nuclear morphometry and AgNOR analysis on cytologic imprints could be a diagnostically useful method in the assessment of mucinous ovarian tumors.     

Modified silver staining of nucleolar organizer regions to improve the accuracy of image analysis

Silver staining of nucleolar organizer regions (NORs) and their subsequent quantification by image analysis are used increasingly in human pathological specimens and experimental models. Because certain conditions determined by the type of tissue and/or its fixation render AgNOR segmentation for image analysis difficult due to insufficient contrast or nonspecific silver precipitation, we propose three improvements to the original technique to overcome these difficulties. Pretreatment with 7% nitric acid produced very distinct dark brown images of AgNORs on a yellow background. The gradient of background colors allowed easy discrimination of nucleolar, nuclear and cytoplasmic structures. Seven morphometric parameters related to number, size and shape of AgNORs were evaluated quantitatively by image analysis on sections pretreated with nitric acid and on adjacent sections treated with citrate buffer in a wet autoclave according to the most widely accepted method for image analysis of AgNOR. Both methods yielded similar results. A second improvement was achieved by coating the slides with 7% celloidin solution in ethyl alcohol-ether prior to AgNOR staining and acid pretreatment. This coating prevented nonspecific silver deposition on argyrophilic bacteria and other tissue debris in human vaginal smears that could make visualizing AgNOR sites difficult. Finally, placing sections face down on the staining solution prevents the formation of nonspecific silver precipitates. These procedures can be applied together or separately according to the requirements of the material to be evaluated.     

Modified silver staining of nucleolar organizer regions to improve the accuracy of image analysis

Silver staining of nucleolar organizer regions (NORs) and their subsequent quantification by image analysis are used increasingly in human pathological specimens and experimental models. Because certain conditions determined by the type of tissue and/or its fixation render AgNOR segmentation for image analysis difficult due to insufficient contrast or nonspecific silver precipitation, we propose three improvements to the original technique to overcome these difficulties. Pretreatment with 7% nitric acid produced very distinct dark brown images of AgNORs on a yellow background. The gradient of background colors allowed easy discrimination of nucleolar, nuclear and cytoplasmic structures. Seven morphometric parameters related to number, size and shape of AgNORs were evaluated quantitatively by image analysis on sections pretreated with nitric acid and on adjacent sections treated with citrate buffer in a wet autoclave according to the most widely accepted method for image analysis of AgNOR. Both methods yielded similar results. A second improvement was achieved by coating the slides with 7% celloidin solution in ethyl alcohol-ether prior to AgNOR staining and acid pretreatment. This coating prevented nonspecific silver deposition on argyrophilic bacteria and other tissue debris in human vaginal smears that could make visualizing AgNOR sites difficult. Finally, placing sections face down on the staining solution prevents the formation of nonspecific silver precipitates. These procedures can be applied together or separately according to the requirements of the material to be evaluated.     

Morphometry and digital AgNOR analysis in cytological imprints of benign, borderline and malignant serous ovarian tumours

AIM: The aim of the study was to determine values of a quantitative morphometry analysis of nuclear characteristics and argyrophilic nucleolar organizer regions (AgNORs) in differential cytodiagnosis of benign, atypically proliferating (borderline) and malignant serous ovarian tumours. METHODS: Cytological imprints of benign (n = 20), borderline (n = 19) and malignant (n = 20) ovarian serous tumours were analysed. A computerized, digital analysis was used to determine morphometric nuclear features, the number and characteristics of single AgNORs, cluster AgNORs, total AgNOR and AgNOR area/nucleus (relative area) ratio. According to their size AgNORs were classified in three categories. A one-way variance analysis and post hoc test (Scheffé) were used for statistical analysis. RESULTS: The morphometric nuclear analysis showed that benign, borderline and malignant serous ovarian tumours are statistically different (P < 0.001) according to the area and outline, the values being highest in malignant tumours and lowest in the borderline group. Digital analysis of AgNORs in benign, borderline and malignant groups showed that the total AgNOR number increases with progression of the lesion (meaning tumour malignancy) significantly (P < 0.001) between benign and malignant as well as between borderline and malignant serous ovarian tumours (P < 0.001). The progression of the lesion malignancy was accompanied by a significant (P < 0.001) progressive increase of the total and relative AgNOR area per nucleus. The AgNOR size increases from benign to malignant tumours and a statistically significant difference (P < 0.001) was observed in all three groups regarding small and large AgNORs. CONCLUSION: Combining different markers of morphometric nuclear characteristics and AgNOR values could improve differential cytodiagnosis of benign, borderline and malignant serous ovarian tumours.     

Nucleolar organizer regions in meningiomas. Correlation with histopathologic malignancy grading, DNA cytometry and clinical outcome

Eighty-one meningiomas (63 grade I, 9 grade II and 9 grade III) and 2 meningeal sarcomas (grade IV) were investigated by a simple one-step silver staining for nucleolar organizer region (NOR)-associated proteins (AgNOR technique) and by DNA cytometry. The number of NORs per cell and the NOR area per cell were correlated with the histopathologic grading, as were the 5c exceeding rate and the 2c deviation index (2cDI) obtained by DNA cytometry. The differences in NOR parameters were only significant (at P less than .001) between grades I and II; P was less than .05 for the 2cDI between grades I and II. No significant differences between grades II and III were found. Among recurrent tumors, the AgNOR technique revealed the proliferative potential in 8 of 11 tumors studied, whereas DNA cytometry failed to recognize malignant features in 8 of 10 tumors investigated.     

Analysis of nucleolar organizing regions in parents of trisomic spontaneous abortions

Summary Nucleolar organizing region (NOR) variants of parents of karyotyped spontaneous abortions were examined to fest the hypothesis that double NORs are important in the genesis of acrocentric trisomies. We were unable to detect any significant difference in the frequency or types of NOR variants between parents of acrocentric trisomies and parents of other types of spontaneous abortions, nor did we identify a double NOR in either group. Thus, it seems unlikely that double NORs are of major significance in the etiology of acrocentric trisomies.     

正常造血细胞的核仁组成区计数定量研究

本文应用银染技术对正常造血细胞的核仁组成区进行了计数定量研究。结果显示,在粒系和红系中,随细胞的成熟,细胞中簇状ＡｇＮＯＲ的数量逐渐减少．而点状ＡｇＮＯＲ数量逐渐增多,无分裂能力的成熟细胞仅有少数点状ＡｇＮＯＲ。淋巴细胞中为一完全集结的银染颗粒,而巨核细胞内为各自分离的点状银染颗粒。本结果为正常造血细胞的核仁组成区提供了基础数值。     

Argyrophilic nucleolar organizing region associated protein synthesis in hair root cells of humans at different developmental stages and sex

Abstract

Argyrophilic nucleolar organizing region (AgNORs) associated proteins are important for cell proliferation and various diseases. We investigated AgNOR protein synthesis in hair root cells of males and females at different ages using two-dimensional image analysis. Experiments were performed on 58 healthy male and 24 healthy female volunteers in three groups according to age and sex. Hair root cells obtained from hair follicles were stained with silver. Total AgNOR number/total nuclear number (TAN/TNN) and total AgNOR area/nuclear area (TAA/NA) for each nucleus were analyzed. The only significant difference was observed in TAA/NA values for males and females from 6 to 12 years old. We suggest that the difference is due to high NOR activity caused by increased growth hormone production in hair root cells.     

A Population Analysis of the Structure and Variability of NOR in Salmo Trutta by Ag, CMA3 and ISH

An analysis of the variation in the number and location of rDNA genes has been carried out in two populations of brown trout (Salmo trutta) from Poland by using Ag and CMA₃-staining, and rDNA in situ hybridisation. We observed an interindividual variation in arm number with NF = 100, 101, and 102. This variation was connected with the size polymorphism of the short (NOR-bearing) arm of the chromosome pair 11. The population studied showed a multichromosomal distribution of active NORs. Atypical Ag-NORs consisted of rDNA genes, as evidenced by rDNA-ISH. In addition to individuals with standard NORs, specimens with extra NORs as well as others with only one active NOR and single interphase nucleolus were observed. This revised version was published online in August 2006 with corrections to the Cover Date.