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At least 163 records · Page 9Linked to original sources
PubMed1993

Nucleolar organizer regions and glycoprotein-hormone alpha-chain reaction as markers of malignancy in endocrine tumours of the pancreas.

The value of silver staining of nucleolar organizer regions (AgNORs) and human chorionic gonadotropin alpha-chain reaction (HCG-alpha) as markers of malignancy was investigated in 60 primary pancreatic endocrine tumours, 37 of which had metastasized at the time of surgery, and in one of which metastases developed 4 years after surgery. Assessment of AgNORs by digital image analysis revealed few but large AgNORs (mean number 2.5 +/- 1.1; mean area 0.32 +/- 0.1 microns 2) in the 22 benign tumours and many but small AgNORs (mean number 5.1 +/- 1.9, P < 0.05; mean area 0.18 +/- 0.09 microns 2, P < 0.01) in the malignant tumours. Quantification of the number of AgNORs per tumour cell nucleolus (AgNOR distribution score) showed that 96% (26/27) of tumours exhibiting at least 5% of cells with more than six AgNORs per nucleolus showed metastases either at the time of diagnosis or up to 4 years after surgery. HCG-alpha immunoreactive cells were present in 25/38 (66%) malignant tumours and in 4/22 (18%) benign tumours. Combined evaluation of AgNOR distribution and HCG-alpha scores showed a high positive predictive value of 96% in cases with a raised AgNOR distribution score irrespective of the HCG-alpha status. A good negative predictive value (81%) was, however, only obtained if both parameters, AgNOR distribution and HCG-alpha scores, were negative. Thus, investigation of AgNORs and HCG-alpha is helpful in predicting malignancy in a high percentage of pancreatic endocrine tumours.

Adolescent↗
PubMed1995

Abnormal integrity of the nucleolus associated with cell cycle arrest owing to the temperature-sensitive ubiquitin-activating enzyme E1.

A mouse cell mutant, ts85, containing the temperature-sensitive ubiquitin-activating enzyme was arrested in G2 phase at the non-permissive temperature. In the arrested cells, azure C, a nucleolus-specific stain, revealed a U-shaped or ring-shaped arrangement of nucleolar lobes with an unstained region in the center. Silver staining of the nucleolar organizer region (NOR) and fluorescence in situ hybridization (FISH) with rDNA both gave signals in azure C-positive regions. Electron microscopic examination revealed a cloud of unidentified electron-dense particles (diameter approximately 70 nm) in the azure C-negative center space. When the arrested cells were released into M-phase, we observed the association of NOR-bearing chromosomes with a pulverization-like abnormality. FISH with rDNA and NOR silver staining demonstrated that the pulverization-like abnormality was restricted to NORs. The frequent occurrence of persistent nucleolar material in prophase and prometaphase of the stressed cells after release indicated a delayed dissociation of the nucleolus that brought about the abnormal chromosomes in M-phase. ts85 cells transfected with the mouse E1 cDNA recovered growth at the non-permissive temperature and no longer showed abnormal nucleolar morphology. It seems that the ubiquitin system plays a role in the dissolution of the nucleolus, possibly involving the NOR-bearing chromosomes.

Animals↗
PubMed1984

Distribution of U3 snRNA in the nucleolus of CHO cells.

Localization of snRNA at the ultrastructural level was studied in the nucleolus of CHO cells by EM autoradiography. In conditions where snRNA U3 is the only RNA species labelled in the nucleolus, silver grains were largely found at the periphery, over the granular ribonucleoprotein component and the perinucleolar condensed chromatin; this enrichment was quantitatively significant. Inhibition of pre-rRNA synthesis with actinomycin D did not alter the concentration or the distribution of U3 inside the nucleolus. The results are consistent with the demonstration that U3 is hydrogen-bonded to 28S pre-rRNA, and thus should be found in the granular compartment where 32S-28S pre-rRNA is assembled into 55s RNP.

Animals↗
PubMed2006

[Cytometric characterization of the cell nucleus and nucleolus apparatus in dysplasia and exocervical cancer of the cervix uteri].

The morphometric parameters of the nucleonucleolar apparatus of the intact stratified squamous epithelium of the cervix uteri, dysplasias, and exocervical cancer were studied by computed morphometry of 50% silver nitrate solution-stained cytological specimens in order to study nucleolar organizers. It was shown that dysplastic changes and malignant transformation were marked by a progressive increase in the values of morphometric parameters of its nucleonucleolar apparatus. The staining of nucleolar organizers is relatively simple and it is expedient to use it for a specifying cytological diagnosis. The advantage of the staining is to identify rare atypical cells in cytological specimens.

Adolescent↗
PubMed1975

[Preliminary data on "fibrillary centers" of the nucleolus of various cells of the ovarian follicle of a lizard Lacerta muralis Laur].

The nucleolus of the thecal cells and little cells of the granulosa contains generally a single "fibrillar center" surrounded by the dense fibrous material of the nucleolus. The "fibrillar centers" are in contact with nucleolar associated heterochromatin. Cytochemical results show that "fibrillar centers" are chiefly composed of proteins which are revealed as ribonucleoproteins with the EDTA method, but the amount of RNA associated with these proteins seems to be small. It is possible that the fibrillar center also contains a little DNA.

Animals↗
PubMed1985

The relation of nucleolus diameter to cell body diameter in mammalian dorsal root ganglion cells.

The present study correlates cell body and nucleolar sizes for dorsal root ganglion cells in the rat. To do this, we measured cell body areas and calculated their diameters and measured nucleolar diameters for 719 cells. These data indicate that there is a correlation in that increasing cell size is associated with increasing nucleolar size. However, there is considerable variability of cell body size for each nucleolar diameter and vice versa. Nevertheless, when nucleolar diameters are grouped, the function 1n D = 1.687 + 0.334 dr, where D is the diameter of the cell body and dr the rounded diameter of the nucleolus, produced an almost straight line. Thus this formula provides a good estimate of the relation of nucleolar and cell body sizes for dorsal root ganglion cells of the rat. In addition, estimates of the variances of cell body size at each nucleolar diameter are provided.

Animals↗
PubMed1993

Diagnostic value of AgNOR staining in follicular cell neoplasms of the thyroid: comparison of evaluation methods and nucleolar features.

The diagnostic value of argyrophil staining of nucleolar organizer regions (AgNOR) was studied in 95 nonneoplastic and neoplastic follicular lesions of the thyroid. Different AgNOR parameters such as number, size, and distribution pattern were determined using digital image analysis. In addition, nuclear and nucleolar size as well as the percentage of nucleoli touching the nuclear membrane (nucleolar margination) were assessed. A stepwise increase in nuclear size and AgNOR counts from normal thyroid tissue to follicular adenoma as well as from differentiated follicular to anaplastic carcinoma was found (mean nuclear area [micron2]/mean AgNOR number per cell: 21.5/1.6 vs. 34.4/3.5 and 45.3/5.0 vs. 66.5/10.8, p < 0.01/p < 0.001). There was, however, no clear separation between these diagnostic groups. In contrast, an almost total discrimination between follicular adenoma and carcinoma was achieved by quantification of AgNORs per tumor cell nucleolus (AgNOR distribution score). In benign adenomas, 3.3% (range, 0-8.8%) of the cells showed nucleoli with at least five AgNOR dots within one focal plane, whereas in follicular carcinomas, the corresponding value was 34.1% (range, 12-75%). Two of four cases of so-called atypical adenomas showed values in the range of benign adenomas, and two were in the range of follicular carcinomas. In comparison with other nuclear and nucleolar parameters, the AgNOR distribution score proved the most valuable diagnostic criterion for the cytomorphological differentiation between follicular adenoma and carcinoma of the thyroid.

Adenocarcinoma, Follicular↗
PubMed2004

[Research of anti-proliferation of curcumin on A549 human lung cancer cells and its mechanism].

OBJECTIVE: To investigate the mechanism of anti-tumor effects of curcumin on human lung cancer cell (A549). METHOD: MTT colorimetry method, fluoroscope, FCM combine PI and Annexin V-FITC double pigmentation method and Western blot method were used. RESULT: Under the effect of the curcumin, cell grew against the wall and suspended in the culture liquid, the A549 cell nucleolus were found fragmentated into different size of apoptosis body under fluoroscopy. The cell proliferation were obvious suppressed after treated with different concentration curcumin for 72 hours. The IC50 were 18 micromol/L by using linear regression. The apoptosis induced by curcumin of A549 cell is concentration dependent. With curcumin increased from 5 micromol/L to 30 micromol/L, Annexin-FITC single positive cell (early apoptosis cell) increased from 3.4% to 59.1%. When curcumin concentration reached 40 micromol/L, PI and Annexin V-FITC double positive cell (secondary apoptosis necrosis cell) became major part of cells, and the cell showed G2 phase block. Observed with western blot method, with the increase of curcumin concentration to 10 micromol/L, the expression of PARP increased simultaneously. CONCLUSION: Curcumin can interfere cell growth cycle of A549 cell and suppress cell growth. The suppression effect is concentration dependent. The effect depends not only from the nonspecific cytotoxic but also from induced cell apoptosis.

Adenocarcinoma↗