Thioacetamide (TA) is converted into a hyperacetylating agent which causes hepatic necrosis, regeneration, cirrhosis and cancerous transformation. One of the most characteristic toxicities of TA in rat is observed with a 50 mg/kg per day which induces nucleolar enlargement different from that in regenerating liver. From TA-treated liver, the nucleoli were isolated and characterized for an altered nucleolar signal transduction system. Immunochemistry revealed that the poisoned nucleoli had increased levels of both nucleolus specific proteins (nucleophosmin and nucleolin) and various signal molecules (CK2, Erk1/2, p38, protein kinases A and C, and cyclin A). Using flow cytometry, the nucleoli were found to be in G2-arrested nuclei. Manifestation of the nucleolar enlargement could be readily observed using an ex vivo hepatocyte culture. There were two types of nucleolar enlargement. One was observed in normal hepatocytes with light density of enlarged nucleoli. The other was in TA-treated hepatocytes with dense and compact density of enlarged nucleoli, which contained a 3 to 5-fold higher nudeophosmin content than the control. In vitro induction of nucleolar enlargement with TA was possible. As soon as the hepatocytes anchored on a collagen coat, exogeneous TA (higher than 1 microg/mL) could induce dense and compact nucleoli. However, when an exogeneous drug was added after monolayer formation (1 day), no drug-induced nucleolar enlargement was observed.
Animal ; Cells, Cultured ; Flow Cytometry ; G2 Phase/drug effects ; Hepatocytes/ultrastructure ; Hepatocytes/drug effects* ; Male ; Nucleolus Organizer Region/physiology ; Nucleolus Organizer Region/drug effects* ; Rats ; Rats, Sprague-Dawley ; Signal Transduction/drug effects ; Thioacetamide/toxicity*

To investigate the histopathological characteristics of inverted papillomas of the urinary bladder, including the possibility of malignant transformation, we studied the indicators of cellular proliferation activity in 7 inverted papillomas of the bladder including two cases of malignant inverted papilloma of the bladder. PCNA expression rates in two cases of malignant inverted papilloma were higher than in benign inverted papillomas. Mean numbers of AgNORs per nucleus in malignant inverted papillomas were much more than in benign inverted papillomas. The c-erbB-2 oncoprotein was expressed only in malignant inverted papillomas. These results suggest that PCNA expression rate, mean number of AgNORs per nucleus and c-erB-2 oncoprotein expression may be merited as good indicators to detect the inverted papilloma with more proliferative and aggressive lesions, and with the potential of malignant transformation.
Adult ; Bladder Diseases/pathology ; Bladder Neoplasms/chemistry/*pathology ; Cell Division/physiology ; Cell Transformation, Neoplastic/pathology ; Female ; Human ; Male ; Middle Age ; Nitrosourea Compounds/analysis ; Nucleolus Organizer Region/chemistry ; Papilloma, Inverted/chemistry/*pathology ; Receptor, erbB-2/analysis ; Silver Staining

Fifteen cases of papillary cystic tumor of the pancreas (PCTP) were studied (14 female patients, one male patient; mean age: 23.5 years). Most tumors developed in the head of the pancreas as a well circumscribed large mass. The tumor had a mean diameter of 6.7 cm(range; 2 to 15 cm). Histopathologically abundant delicate papillary fragments, monomorphic tumor cells and degenerative changes of the solid area of the tumor were characteristic. All but two cases had completely circumscribed capsules. Two cases had duodenal invasion; one of all cases had cul de sac metastasis. Compared with 12 non-aggressive tumors, the aggressive cases had larger tumor size (more than 9 cm) with a thicker capsule (more than 2 mm). In studies to investigate the prognostic index using nucleolar organizing region (NOR), proliferating cell nuclear antigen (PCNA) and flow cytometry as well as nuclear grade and mitotic index, we could not find the useful parameter to detect the malignant potential of PCTP. In the flow cytometric analysis of cellular DNA contents, two invasive cases and the only one case of the male patient among the non-aggressive group were aneuploid. In conclusion, although it is hard to predict the prognosis by microscopic findings only, those with a thick capsule and aneuploidy tend to be related to malignant potential.
Adolescent ; Adult ; Cell Division/physiology ; Cystadenoma, Papillary/*chemistry/*pathology ; Female ; Flow Cytometry ; Human ; Immunohistochemistry ; Male ; Nucleolus Organizer Region/chemistry ; Pancreatic Cyst/*chemistry/*pathology ; Pancreatic Neoplasms/*chemistry/*pathology ; Predictive Value of Tests ; Prognosis ; Proliferating Cell Nuclear Antigen/analysis ; Silver Staining ; Support, Non-U.S. Gov't

Toxoplasma gondii GRA10 expressed as a GFP-GRA10 fusion protein in HeLa cells moved to the nucleoli within the nucleus rapidly and entirely. GRA10 was concentrated specifically in the dense fibrillar component of the nucleolus morphologically by the overlap of GFP-GRA10 transfection image with IFA images by monoclonal antibodies against GRA10 (Tg378), B23 (nucleophosmin) and C23 (nucleolin). The nucleolar translocalization of GRA10 was caused by a putative nucleolar localizing sequence (NoLS) of GRA10. Interaction of GRA10 with TATA-binding protein associated factor 1B (TAF1B) in the yeast two-hybrid technique was confirmed by GST pull-down assay and immunoprecipitation assay. GRA10 and TAF1B were also co-localized in the nucleolus after co-transfection. The nucleolar condensation of GRA10 was affected by actinomycin D. Expressed GFP-GRA10 was evenly distributed over the nucleoplasm and the nucleolar locations remained as hollows in the nucleoplasm under a low dose of actinomycin D. Nucleolar localizing and interacting of GRA10 with TAF1B suggested the participation of GRA10 in rRNA synthesis of host cells to favor the parasitism of T. gondii.
Alpha-Amanitin/pharmacology ; Animals ; Antibodies, Monoclonal/analysis/metabolism ; Antibodies, Protozoan/analysis/metabolism ; Dactinomycin/pharmacology ; Fluorescent Antibody Technique, Direct ; Gene Expression/*physiology ; Green Fluorescent Proteins/genetics ; Hela Cells ; Humans ; Mice ; Mice, Inbred BALB C ; Nucleic Acid Synthesis Inhibitors/pharmacology ; Nucleolus Organizer Region/drug effects/*metabolism ; Pol1 Transcription Initiation Complex Proteins/metabolism ; Protein Sorting Signals/physiology ; Protozoan Proteins/*biosynthesis/genetics/metabolism ; Recombinant Fusion Proteins/genetics/metabolism ; Toxoplasma/*physiology ; Transfection