Search results for "Cell communication"
showing 10 items of 153 documents
Trans- but not cis-resveratrol impairs angiotensin-II-mediated vascular inflammation through inhibition of NF-κB activation and peroxisome proliferat…
2010
Abstract Angiotensin II (Ang-II) displays inflammatory activity and is implicated in several cardiovascular disorders. This study evaluates the effect of cis- and trans (t)-resveratrol (RESV) in two in vivo models of vascular inflammation and identifies the cardioprotective mechanisms that underlie them. In vivo, Ang-II–induced arteriolar leukocyte adhesion was inhibited by 71% by t-RESV (2.1 mg/kg, i.v.), but was not affected by cis-RESV. Because estrogens influence the rennin-angiotensin system, chronic treatment with t-RESV (15 mg/kg/day, orally) inhibited ovariectomy-induced arteriolar leukocyte adhesion by 81%, partly through a reduction of cell adhesion molecule (CAM) expression and c…
Postnatal Deletion of Numb/Numblike Reveals Repair and Remodeling Capacity in the Subventricular Neurogenic Niche
2006
Neural stem cells are retained in the postnatal subventricular zone (SVZ), a specialized neurogenic niche with unique cytoarchitecture and cell-cell contacts. Although the SVZ stem cells continuously regenerate, how they and the niche respond to local changes is unclear. Here we generated nestin-creERtm transgenic mice with inducible Cre recombinase in the SVZ, and removed Numb/Numblike, key regulators of embryonic neurogenesis from postnatal SVZ progenitors and ependymal cells. This resulted in severe damage to brain lateral ventricle integrity, and identified previously unknown roles for Numb/Numblike in regulating ependymal wall integrity and SVZ neuroblast survival. Surprisingly, the ve…
Dynamic in vivo Imaging of Microvasculature and Perfusion by Miniaturized Confocal Laser Microscopy
2008
<i>Introduction:</i> Microvasculature and associated pathologies mandate dynamic imaging. We evaluated a novel miniaturized confocal laser scanning probe for in vivo visualization of blood vessels, blood flow, cell tracking and perfusion in both healthy rodents and disease models.<i> Methods:</i> The hand-held confocal microscopy system allowed a 500- to 2,400-fold magnification at a dynamically variable imaging depth. Different intravital stains were used alone or in combination for tissue, nuclear, plasma and vascular endothelial cell staining and for blood flow visualization, and targeted staining for individual cell populations. <i>Results:</i> Precis…
Lateral habenula and hippocampus: A complex interaction raphe cells-mediated
1997
The study has shown an excitatory influence exerted by lateral habenula (LH) on hippocampal pyramidal cells. The modulatory influence is paradoxically serotonine-mediated; in fact all LH stimulation effects were abolished by intrahippocampal iontophoretic methysergide application. The data suggest the involvement of dorsal raphe nucleus. In fact, the dorsal raphe nucleus stimulation caused on hippocampus an expected inhibitory effect antagonized by intrahippocampal iontophoretic methysergide application. In the context of this neural structure we have highlighted a disinhibitory relation between two types of cells: slow serotonergic efferent neurones and fast GABAergic interneurones. The di…
Gap junctional intercellular communication of cultured rat liver parenchymal cells is stabilized by epithelial cells and their isolated plasma membra…
1994
The gap junctional intercellular communication (GJIC) determined by measuring dye coupling with Lucifer yellow, decreased within 3 d from 66% to 28% in monocultures of rat liver parenchymal cells. Coculturing of the parenchymal cells with a nonparenchymal epithelial cell line from rat liver resulted in increased and stabilized intercellular communication (83% after 3 d). The presence of isolated plasma membrane vesicles of the nonparenchymal epithelial cells also stabilized the intercellular communication between the liver parenchymal cells (70% after 3 d). When liver parenchymal cells were cocultured with a rat liver fibroblast cell line the gap junctional communication between the parench…
Immune escape mechanism: defective resting and stimulated leukocyte-endothelium interaction in hepatocellular carcinoma of the rat.
2004
Hepatocellular carcinoma represents an increasing therapeutic challenge due to its high incidence and early metastasis. Numerous studies have demonstrated the influence of the vascular system on tumor growth and development. In addition, the role of leukocyte-endothelium interaction in tumor vessels is of particular significance with regard to immunological tumor therapy. In this study we used an experimental in vivo animal model that allows a quantitative analysis on vessel morphology, microcirculation, and leukocyte-endothelium interaction. The vessel architecture in tumor tissue was found to be extremely heterogeneous, with a consecutively variable blood flow velocity. Following superfus…
Aprotinin inhibits leukocyte–endothelial cell interactions after hemorrhage and reperfusion
2003
Background. The serine protease inhibitor aprotinin has been successfully used to reduce blood loss in patients undergoing cardiac operations. We studied aprotinin for its ability to modulate leukocyte– endothelial cell interactions after ischemia and reperfusion. Methods. The effects of aprotinin on leukocyte– endothelial cell interactions were observed by intravital microscopy in the rat mesenteric microcirculation and immunohistochemical analysis. The inflammatory cascade (leukocyte rolling, firm adherence, and transmigration) was studied after thrombin stimulation and after hemorrhage and reperfusion. Results. Intravenous bolus administration of aprotinin treatment (20,000 U/kg) signifi…
Estrogens inhibit angiotensin II-induced leukocyte-endothelial cell interactions in vivo via rapid endothelial nitric oxide synthase and cyclooxygena…
2002
Angiotensin II (Ang II) may be a key molecule in the development of atherosclerosis. Because the incidence of coronary atherosclerosis in premenopausal women is lower than that observed in men or postmenopausal women, we have investigated the effect of estrogens on Ang II–induced leukocyte recruitment in vivo using intravital microscopy in the rat mesenteric microcirculation. Superfusion for 60 minutes with Ang II induced a significant increase in leukocyte rolling flux, adhesion, and emigration. Administration of 17-β-estradiol (17-β-E) after 30 minutes of Ang II superfusion produced a reduction of these leukocyte responses by 55.1%, 72.7%, and 70.9%, respectively, an additional 30 minutes…
Identification and phenotypic characterization of a subpopulation of T84 human colon cancer cells, after selection on activated endothelial cells
2004
The extravasation of metastatic cells is regulated by molecular events involving the initial adhesion of tumor cells to the endothelium and subsequently the migration of the cells in the host connective tissue. The differences in metastatic ability could be attributed to properties intrinsic of the various primary tumor types. Thus, the clonal selection of neoplastic cells during cancer progression results in cells better equipped for survival and formation of colonies in secondary sites. A cell line (T84SF) exhibiting an altered phenotypic appearance was selected from a colon cancer cell line (T84) by repetitive plating on TNFα-activated human endothelial cells and subsequent selection for…
Lack of effect of oxytocin on the numbers of ?synaptic? ribbons, cyclic guanosine monophosphate and serotonin N-acetyltransferase activity in organ-c…
1993
In addition to the stimulating influence of the sympathetic system on the function of the mammalian pineal gland, neuropeptides such as neuropeptide Y, vasoactive intestinal polypeptide and arginine-vasopressin (AVP) are thought to function as modulators. Since AVP has been shown to influence pineal melatonin synthesis, the aim of the present study was to investigate the possible effects of the second hypothalamic nonapeptide oxytocin (OT), which likewise has been detected in the pineal gland. We therefore studied "synaptic" ribbon (SR) numbers, N-acetyltransferase (NAT) activity and the intracellular concentration of cyclic guanosine monophosphate (cGMP) following in vitro incubation of ra…