Cellular Area (cellular + area)

Distribution by Scientific Domains

Selected Abstracts

Expression of constructs of the neuronal isoform of myosin-Va interferes with the distribution of melanosomes and other vesicles in melanoma cells

CYTOSKELETON, Issue 2 2002
Joo Carlos da Silva Bizario
Abstract Myosin-Va has been implicated in melanosome translocation, but the exact molecular mechanisms underlying this function are not known. In the dilute, S91 melanoma cells, melanosomes move to the cell periphery but do not accumulate in the tips of dendrites as occurs in wild-type B16 melanocytes; rather, they return and accumulate primarily at the pericentrosomal region in a microtubule-dependent manner. Expression of the full-length neuronal isoform of myosin-Va in S91 cells causes melanosomes to disperse, occupying a cellular area approximately twice that observed in non-transfected cells, suggesting a partial rescue of the dilute phenotype. Overexpression of the full tail domain in S91 cells is not sufficient to induce melanosome dispersion, rather it causes melanosomal clumping. Overexpression of the head and head-neck domains of myosin-Va in B16 cells does not alter the melanosome distribution. However, overexpression of the full tail domain in these cells induces melanosome aggregation and the appearance of tail-associated, aggregated particles or vesicular structures that exhibit variable degrees of staining for melanosomal and Golgi ,-COP markers, as well as colocalization with the endogenous myosin-Va. Altogether, the present data suggest that myosin-Va plays a role in regulating the direction of microtubule-dependent melanosome translocation, in addition to promoting the capture of melanosomes at the cell periphery as suggested by previous studies. These studies also reinforce the notion that myosin-V has a broader function in melanocytes by acting on vesicular targeting or intracellular protein trafficking. Cell Motil. Cytoskeleton 51:57,75, 2002. 2002 Wiley-Liss, Inc. [source]

On optimal cell planning: Case study for a DCS 1800 system

Stavroula Bouzouki
Abstract Micro and pico cell planning strategies are adopted in personal communication systems (PCS) in order to increase their capacity. The usage of the upper UHF band in combination with greater bandwidth is already proposed by telecom engineers in order to achieve the promised service quality and data rates. These strategies are characterized by an increased number of cells in specific geographical areas with the corresponding operating base transceiving stations (BTS) located at relatively low heights above the street level. In this case, the cell planning procedure in linear streets under line-of-sight (LOS) conditions needs further study concerning the technical characteristics of the PCS. In this paper, the propagation characteristics of a DCS 1800 system are investigated on a theoretical and experimental basis in a specific geographical area (center of Patras City in Northern Pelloponesse). An improved RF propagation model is proposed in order to determine the propagation path losses occurring under certain multipath fading conditions. Hence an optimum determination of a system's cellular area can be achieved. Copyright 2001 John Wiley & Sons, Ltd. [source]

Intact corneal stroma visualization of GFP mouse revealed by multiphoton imaging

Wen Lo
Abstract The aim of this work is to demonstrate that multiphoton microscopy is a preferred technique to investigate intact cornea structure without slicing and staining. At the micron resolution, multiphoton imaging can provide both large morphological features and detailed structure of epithelium, corneal collagen fibril bundles and keratocytes. A large area multiphoton cross-section across an intact eye excised from a GFP mouse was obtained by a homebuilt multiphoton microscope. The broadband multiphoton fluorescence (435,700 nm) and second harmonic generation (SHG, 360,400 nm) signals were generated by the 760 nm output of a femtosecond titanium-sapphire laser. A water immersion objective (Fluor , 40X, NA 0.8; Nikon) was used to facilitate imaging the curve ocular surface. The multiphoton image over entire cornea provides morphological information of epithelial cells, keratocytes, and global collagen orientation. Specifically, our planar, large area multiphoton image reveals a concentric pattern of the stroma collagen, indicative of the laminar collagen organization throughout the stroma. In addition, the green fluorescence protein (GFP) labeling contributed to fluorescence contrast of cellular area and facilitated visualizing of inactive keratocytes. Our results show that multiphoton imaging of GFP labeled mouse cornea manifests both morphological significance and structural details. The second harmonic generation imaging reveals the collagen orientation, while the multiphoton fluorescence imaging indicates morphology and distribution of cells in cornea. Our results support that multiphoton microscopy is an appropriate technology for further in vivo investigation and diagnosis of cornea. Microsc. Res. Tech., 2006. 2006 Wiley-Liss, Inc. [source]

Reactive proliferation of endothelial cells and pericytes associated with arteriovenous malformation

Masahito YASUDA
Abstract Arteriovenous malformation (AVM) is a structural vascular abnormality with no proliferation of cellular components. We report on a 53-year-old man who presented with a 15-year history of a progressively enlarging nodule on his lower lip. A dark-reddish, easy-bleeding nodule diagnosed as AVM was resected to reduce the volume and troublesome bleeding. Histologically, the nodule revealed that the proliferating cellular area was composed of endothelial cells and pericytes in addition to the area of dilated vessels. We speculated that the cell proliferation developed secondary to AVM. We also discuss the histological differential diagnosis of spindle cell hemangioma and pseudo-Kaposi's sarcoma. [source]

Congenital myofibroma of the skin mimicking a piloleiomyoma

Takuya Inoue
Myofibroma is an uncommon benign soft tissue disorder, which is usually congenital or present in early infancy. Myofibroma usually manifests as a single mass. When there are multiple lesions, the term myofibromatosis is used. The characteristic histopathological feature of the myofibroma is the coexistence of two distinct areas. One area mainly contains plump spindle cells with thin blunt-ended nuclei and eosinophilic cytoplasm, thus indicating myoid characteristics. The other area contains either round or polygonal cells with slightly pleomorphic, hyperchromatic nuclei or small spindle cells typically arranged around a distinct hemangiopericytoma-like vascular pattern. In the present case, the majority of the tumor was composed of the plump myoid spindle cells. This led to an initial diagnosis of a piloleiomyoma. However, the tumor cells were not immunohistochemically positive for desmin. Moreover, careful examination revealed a hemangiopericytoma-like vascular pattern characterized by the presence of high cellular areas with irregular vascular spaces. These features led to the final diagnosis of the myofibroma. It is therefore important to recognize the leiomyoma-like variants of myofibromas. Inoue T, Sada A, Mori T, Misago N, Narisawa Y. Congenital myofibroma of the skin mimicking a piloleiomyoma. [source]