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Actin Staining (actin + staining)

Distribution by Scientific Domains
Life Sciences60%

Selected Abstracts

Dexamethasone alters F-actin architecture and promotes cross-linked actin network formation in human trabecular meshwork tissue

CYTOSKELETON, Issue 2 2005
Abbot F. Clark
Abstract Elevated intraocular pressure is an important risk factor for the development of glaucoma, a leading cause of irreversible blindness. This ocular hypertension is due to increased hydrodynamic resistance to the drainage of aqueous humor through specialized outflow tissues, including the trabecular meshwork (TM) and the endothelial lining of Schlemm's canal. We know that glucocorticoid therapy can cause increased outflow resistance and glaucoma in susceptible individuals, that the cytoskeleton helps regulate aqueous outflow resistance, and that glucocorticoid treatment alters the actin cytoskeleton of cultured TM cells. Our purpose was to characterize the actin cytoskeleton of cells in outflow pathway tissues in situ, to characterize changes in the cytoskeleton due to dexamethasone treatment in situ, and to compare these with changes observed in cell culture. Human ocular anterior segments were perfused with or without 10,7 M dexamethasone, and F-actin architecture was investigated by confocal laser scanning microscopy. We found that outflow pathway cells contained stress fibers, peripheral actin staining, and occasional actin "tangles." Dexamethasone treatment caused elevated IOP in several eyes and increased overall actin staining, with more actin tangles and the formation of cross-linked actin networks (CLANs). The actin architecture in TM tissues was remarkably similar to that seen in cultured TM cells. Although CLANs have been reported previously in cultured cells, this is the first report of CLANs in tissue. These cytoskeletal changes may be associated with increased aqueous humor outflow resistance after ocular glucocorticoid treatment. Cell Motil. Cytoskeleton 60:83,95, 2005. © 2004 Wiley-Liss, Inc. [source]

Sarcomatoid eccrine porocarcinoma: report of two cases and a review of the literature

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2007
Seng Geok Nicholas Goh
To the best of our knowledge, there has been no report in the English literature of porocarcinoma with predominantly undifferentiated sarcomatous change. We present two cases of sarcomatoid eccrine porocarcinoma associated with a benign poroma. Case 1 pertained to an 82-year-old woman with an ulcerated chest wall tumor, and Case 2 was that of a 74-year-old woman who presented with an ulcerated plaque in the lower leg. Case 1 showed an unusual pseudo-angiosarcomatous morphology with spindle cells dissecting through collagen bundles and forming vascular like channels. Case 2 revealed high-grade malignant spindle cells with focal evidence of ductal differentiation. In both the cases, benign poromatous elements were histologically evident. Immunohistochemistry performed showed pancytokeratin positivity in spindle cells of both lesions. Epithelial membrane antigen and carcino-embryonic antigen positivity in the malignant ductal elements and focal smooth muscle actin staining of the spindle cells were demonstrated in Case 2. A brief review of relevant literature is presented. [source]

Air-liquid interface (ALI) culture of human bronchial epithelial cell monolayers as an in vitro model for airway drug transport studies

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2007
Hongxia Lin
Abstract Serially passaged normal human bronchial epithelial (NHBE) cell monolayers were established on Transwell® inserts via an air-liquid interface (ALI) culture method. NHBE cells were seeded on polyester Transwell® inserts, followed by an ALI culture from day 3, which resulted in peak TEER value of 766,±,154 ,,×,cm2 on the 8th day. Morphological characteristics were observed by light microscopy and SEM, while the formation of tight junctions was visualized by actin staining, and confirmed successful formation of a tight monolayer. The transepithelial permeability (Papp) of model drugs significantly increased with the increase of lipophilicity and showed a good linear relationship, which indicated that lipophilicity is an important factor in determining the Papp value. The expression of P-gp transporter in NHBE cell monolayers was confirmed by the significantly higher basolateral to apical permeability of rhodamine123 than that of reverse direction and RT-PCR of MDR1 mRNA. However, the symmetric transport of fexofenadine,·,HCl in this NHBE cell monolayers study seems to be due to the low expression of P-gp transporter and/or to its saturation with high concentration of fexofenadine,·,HCl. Thus, the development of tight junction and the expression of P-gp in the NHBE cell monolayers in this study imply that they could be a suitable in vitro model for evaluation of systemic drug absorption via airway delivery, and that they reflect in vivo condition better than P-gp over-expressed cell line models. ©2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96:341,350, 2007 [source]

Effects of wortmannin and latrunculin A on slow endocytosis at the frog neuromuscular junction

THE JOURNAL OF PHYSIOLOGY, Issue 1 2004
D. A. Richards
Phosphoinositides are key regulators of synaptic vesicle cycling and endocytic traffic; the actin cytoskeleton also seems to be involved in modulating these processes. We investigated the effects of perturbing phosphoinositide signalling and actin dynamics on vesicle cycling in frog motor nerve terminals, using fluorescence and electron microscopy, and electrophysiology. Antibody staining for ,-actin revealed that actin surrounds but does not overlap with synaptic vesicle clusters. Latrunculin A, which disrupts actin filaments by binding actin monomers, and wortmannin, an inhibitor of phosphatidyl inositol-3-kinase (PI3-kinase), each disrupted the pattern of presynaptic actin staining, but not vesicle clusters in resting terminals. Latrunculin A, but not wortmannin, also reduced vesicle mobilization and exocytosis. Both drugs inhibited the stimulation-induced uptake of the styryl dye FM1-43 and blocked vesicle reformation from internalized membrane objects after tetanic stimulation. These results are consistent with a role of PI3-kinase and the actin cytoskeleton in the slow pathway of vesicle endocytosis, used primarily by reserve pool vesicles. [source]