OBJECTIVETo investigate the expression of thymosin beta10 (Tbeta10) and related changes of actin filament organization in human tumor cell lines with different metastatic potential.

METHODSFour groups of nine human tumor cell lines with different metastatic potential were analyzed for the expression of Tbeta10 mRNA detected by northern-blot and its peptide by immunohistochemical staining. The filamentous actin (F-actin) was stained with TRITC-phalloidin to detect changes in actin organization.

RESULTSIn comparison with the non and/or weakly metastatic counterparts, Tbeta10 was upregulated in highly metastatic human lung cancer, malignant melanoma and breast cancer cell lines. TRITC-phalloidin staining revealed less actin bundles and a fuzzy network of shorter filaments in the highly metastatic tumor cells, while in the non and/or weakly metastatic cancer cell lines, there were thick and orderly arranged actin filaments.

CONCLUSIONSTbeta10 levels correlate positively with the metastatic phenotype in human tumors currently examined. The increased metastatic potential of tumor cells is accompanied by the loss of F-actin and poorly organized actin skeleton. There is a consistent correlation between the elevated Tbeta10 expression and the disrupted actin skeleton.

Actins ; analysis ; Blotting, Northern ; Cell Line, Tumor ; Humans ; Immunohistochemistry ; Neoplasm Metastasis ; Thymosin ; analysis

The aim of this study was to determine the relationship of alpha-smooth muscle actin (ASMA) and the proliferation marker Ki-67 of glomerulonephritis (GN). Immunohistochemical stainings with the usual streptavidin-biotin peroxidase method were performed on 86 renal biopsies using monoclonal 1A4 and Ki-67. The results of the quantitative evaluation of ASMA and Ki-67 were analyzed for the correlation between positive value of ASMA and Ki-67 in different GN. ASMA expressions of glomeruli were highest in acute post-infectious GN [APGN; 16.9 Fraction Volume (FV)%], followed by unclassified proliferative GN (UnGN; 12.5 FV%), membranoproliferative GN (MPGN; 8.5 FV%), lupus nephritis (LupusN; 6.3 FV%), IgA nephritis (IgAN; 5.6 FV%), and normal control (0.1 FV%). The Ki-67 staining was considerably elevated in lupusN (4.3 Ki-67 positives/glomerulus), APGN (2.7), MPGN (2.5), UnGN (1.66), IgAN (0.5), compared with that in normal control group (0.1 Ki-67 positives/glomerulus). Ki-67 value in each category of glomerular diseases was significantly different from that in the control biopsies (p<0.004). The relationship between morphometric results of ASMA and Ki-67 was statistically significant regardless of the diagnosis. (rs=0.425, p=0.000, ASMA= 0.1113+0.1665 Ki-67). In conclusion, the immunohistochemical assessment of ASMA and Ki-67 expression in GN might be a reliable indicator for the progression of GN. This study indicates that active cellular proliferation is associated with increased actin deposition in glomeruli.
Actins/*analysis ; Biopsy ; Cell Division ; Glomerulonephritis/*metabolism/pathology ; Human ; Immunohistochemistry ; Ki-67 Antigen/*analysis ; Kidney/pathology

Smooth muscle tumor of the uveal tract is rare, and mostly located in the ciliochoroidal area. We report a unique case of posterior choroidal leiomyoma in a 27-yr-old man. Ophthalmoscopic examination disclosed an 11 mm-sized mass on the fundus two-disc diameters apart from the optic disc. With a suspicion of amelanotic melanoma, the globe was enucleated. The mass occupied the whole thickness of choroidal stroma beneath the pigmented retinal epithelium and composed of spindle cells arranged in intersecting fascicles. Immunohistochemical studies demonstrated immunoreactivities of the tumor cells for smooth muscle actin, desmin, and vimentin. Ultrastructurally, numerous intracytoplasmic filaments with fusiform focal densities, scattered segmental external laminae, subplasmalemmal densities, and pinocytic vesicles were noted. The leiomyoma in this case had several unusual features in that it was confined to the posterior choroid with no relation to the ciliary body, occupied the whole stroma of the choroid instead of suprauveal location, and occurred in a young male. It is important to include choroidal leiomyoma in the differential diagnosis of choroidal tumors.
Actins/analysis ; Adult ; Choroid Neoplasms/chemistry/*pathology ; Desmin/analysis ; Humans ; Leiomyoma/chemistry/*pathology ; Male ; Uveal Neoplasms/chemistry/*pathology ; Vimentin/analysis

The biophysical properties of the extracellular matrix (ECM) dictate tissue-specific cell behaviour. In the skeleton system, bone shows the potential to adapt its architecture and contexture to environmental rigidity via the bone remodelling process, which involves chondrocytes, osteoblasts, osteoclasts, osteocytes and even peripheral bone marrow-derived stem/stromal cells (BMSCs). In the current study, we generated stiff (~1 014 ± 56) kPa, Young's modulus) and soft (~46 ± 11) kPa silicon-based elastomer polydimethylsiloxane (PDMS) substrates by mixing curing agent into oligomeric base at 1:5 and 1:45 ratios, respectively, and investigated the influence of substrate stiffness on the cell behaviours by characterizing cell spreading area, cell cytoskeleton and cell adhesion capacity. The results showed that the cell spreading areas of chondrocytes, osteoblasts, osteoclasts, osteocytes and BMSCs were all reduced in the soft substrate relative to those in the stiff substrate. F-actin staining confirmed that the cytoskeleton was also changed in the soft group compared to that in the stiff group. Vinculin in focal adhesion plaques was significantly decreased in response to soft substrate compared to stiff substrate. This study establishes the potential correlation between microenvironmental mechanics and the skeletal system, and the results regarding changes in cell spreading area, cytoskeleton and cell adhesion further indicate the important role of biomechanics in the cell-matrix interaction.
Actins ; Cell Adhesion ; Elastic Modulus ; Focal Adhesions ; physiology ; Humans ; Vinculin ; analysis ; metabolism

To characterize cellular responses during hepatic regeneration, we examined 13 explant livers and 5 liver allografts by immunohistochemistry for cytokeratin 7, HepPar1, CD68, alpha-smooth muscle actin (alpha-SMA) and proliferating cell nuclear antigen as well as reticulin and Masson-trichrome staining. Within a week after liver damage, elongated CD68-positive cells were detected along the border of necrotic area. The number of alpha-SMA-positive cells was slightly increased along the sinusoids. Ductular proliferation or fibrosis was negligible. After one or two weeks, the size and number of CD68-positive cells were markedly increased. alpha-SMA-positive cells increased in number within lobules and portal tracts. Ductular proliferation occurred predominantly at the limiting plate or along the border of necrotic areas. After one month, necrotic parenchyma was replaced by many ductules, CD68-positive cells, alpha-SMA-positive cells. Nodules of regenerating hepatocytes and irregular fibrosis were diffusely present. Other nonparenchymal cells were not significantly changed. These observations indicate that chronological interaction between nonparenchymal and parenchymal cells occur during the course of human hepatic regeneration and suggest extensive porto-periportal fibrosis more than a few months after the onset of fulminant hepatitis is a major indicator of chronic functional impairment necessitating liver transplantation.
Actins/analysis ; Antigens, CD/analysis ; Antigens, Differentiation, Myelomonocytic/analysis ; Human ; Immunohistochemistry ; Keratin/analysis ; Liver/*cytology ; *Liver Regeneration ; Proliferating Cell Nuclear Antigen/analysis

Pneumocystis carinii causes serious pulmonary infection in immunosuppressed patients. This study was undertaken to observe the cytoskeletal proteins of P. carinii by immuno-electron microscopy. P. carinii infection was experimentally induced by immunosuppression of Sprague-Dawley rats for seven weeks, and their lungs were used for the observations of this study. The gold particles localized actin, tropomyosin, and tubulin. The actin was irregularly scattered in the cytoplasm of the trophic forms but was much more concentrated in the inner space of the cell wall of the cystic forms called the inner electron-lucent layer. No significant amount of tropomyosin was observed in either trophic forms or cystic forms. The tubulin was distributed along the peripheral cytoplasm and filopodia of both the trophic and cystic forms rather than in the inner side of the cytoplasm. Particularly, in the cystic forms, the amount of tubulin was increased and located mainly in the inner electron-lucent layer of the cell wall where the actin was concentrated as well. The results of this study showed that the cell wall of P. carinii cystic forms is a structure whose inner side is rich in actin and tubulin. The location of the actin and tubulin in P. carinii suggests that the main role of these proteins is an involvement in the protection of cystic forms from the outside environment by maintaining rigidity of the cystic forms.
Actins/analysis ; Animals ; Cytoskeletal Proteins/*analysis ; Fungal Proteins/*analysis ; Histocytochemistry ; Microscopy, Immunoelectron ; Pneumocystis/*chemistry/cytology ; Rats ; Rats, Wistar ; Support, Non-U.S. Gov't ; Tropomyosin/analysis ; Tubulin/analysis

Actins ; analysis ; Animals ; Dimethylnitrosamine ; Immunohistochemistry ; Liver ; metabolism ; pathology ; Male ; Necrosis ; chemically induced ; pathology ; Rats ; Rats, Wistar ; Reticulin ; analysis ; Silver Staining

Actins ; analysis ; Antigens, CD34 ; analysis ; Carcinoma, Papillary ; classification ; metabolism ; pathology ; Female ; Humans ; Immunohistochemistry ; Keratin-19 ; analysis ; Keratin-20 ; analysis ; Muscle, Smooth ; chemistry ; Pancreatic Neoplasms ; classification ; metabolism ; pathology ; Proto-Oncogene Proteins c-kit ; analysis ; Receptors, Estrogen ; analysis ; Receptors, Progesterone ; analysis

OBJECTIVETo observe the transdifferentiation of renal tubular epithelial cells in tubulointerstitial fibrosis.

METHODSThe renal tubulointerstitial fibrosis model in Wistar rats was established by unilateral renal vein ligature. The rats were kept 25 days after renal vein ligature. The kidneys were dissected every 5 days by killing 5 rats. The morphological changes of the kidney were observed by light microscopy, electron microscopy, polarizing microscopy and immunohistochemistry method.

RESULTSThe histological changes showed tubular atrophy and disappearance, widening of intertubular spaces with increased lymphocytes and mononuclear cells infiltration and fibrosis. The CK marker in injured and atrophic epithelial cells gradually weakened, but the alpha-SMA, vimentin, TGF-beta(1), collagen I and III showed gradually stronger positivity for immunohistochemistry. Some interstitial cells became positive for CK. Electron microscopy revealed decreased mitochondria, increased endoplasmic reticulum and microfilament of the tubular epithelial cells which merged into the interstitium. During the early stage of tubulointerstitial fibrosis, there was proliferation of type III collagen and then followed by type I collagen at later stage when observing the Sirius Red stained sections under the polarizing microscope.

CONCLUSIONTubular epithelial cells can transdifferentiate to fibroblasts during the process of tubulointerstitial fibrosis.

Actins ; analysis ; Animals ; Cell Differentiation ; Collagen ; analysis ; Epithelial Cells ; cytology ; Fibrosis ; Immunohistochemistry ; Keratins ; analysis ; Kidney Tubules ; chemistry ; pathology ; ultrastructure ; Male ; Rats ; Rats, Wistar

OBJECTIVEThe purpose of this study was to assess weather the immortalized mouse brain endothelial cell line Bend.3 displays the comparative barrier characteristics as the primary brain microvascular endothelial cells (BEMC).

METHODSImmortalized mouse brain endothelial cell line, Bend.3 cells were cultured in transwell inserts and their restrictive characteristics were assessed by transendothelial electrical resistance (TEER) and horseradish peroxidase (HRP) permeability assays. Western blot and direct fluorescent staining methods were used to detect the tight junction protein expression and F-actin distribution.

RESULTSThe TEER in Bend.3 cells increased with the prolonged culture time and increased to 82.3+/-6.0 Omega cm2 10 days after culture, which was significantly higher than that 3 days after culture (37.3+/-3.1 Omega cm2; P<0.05). There were significant differences in the permeability rates for HRP 3 and 10 days after culture (4.3+/-0.20)% vs (2.2+/-0.05)% (P<0.05). Western blot indicated high level expression of tight junction proteins occludin and ZO-1 in Bend.3 cells 10 days after culture. F-actin was visualized around the cell membrane and presented scrobiculate linear fluorescence 10 days after culture.

CONCLUSIONSBend.3 cells have similar barrier characteristics to BEMC, and their barrier function may reach to the best effect 10 days after culture.

Actins ; analysis ; Animals ; Blood-Brain Barrier ; Cell Line ; Electric Impedance ; Endothelial Cells ; metabolism ; Horseradish Peroxidase ; metabolism ; Membrane Proteins ; analysis ; Mice ; Phosphoproteins ; analysis ; Zonula Occludens-1 Protein