Search results for "Models"
showing 10 items of 8211 documents
Wharton's Jelly Stem Cells: A Novel Cell Source for Oral Mucosa and Skin Epithelia Regeneration
2013
Abstract Perinatal stem cells such as human umbilical cord Wharton's jelly stem cells (HWJSCs) are excellent candidates for tissue engineering because of their proliferation and differentiation capabilities. However, their differentiation potential into epithelial cells at in vitro and in vivo levels has not yet been reported. In this work we have studied the capability of HWJSCs to differentiate in vitro and in vivo to oral mucosa and skin epithelial cells using a bioactive three-dimensional model that mimics the native epithelial-mesenchymal interaction. To achieve this, primary cell cultures of HWJSCs, oral mucosa, and skin fibroblasts were obtained in order to generate a three-dimension…
Morphology of cardiac muscle in septic shock. Observations with a porcine septic shock model.
1995
The morphology of cardiac muscle was investigated in a porcine model of septic shock, created by intermitted application of Escherichia coli-endotoxin. The earliest lesions, found after 18 h of septic shock, were endothelial cell swelling, marked leucostasis and slight ischaemic alterations of the muscle fibres. At the end point of the experiments, after 48 h, some fibrin thrombi were found associated with more pronounced ischaemic alterations of cardiac muscle cells and some necrotic fibres. Comparing these findings with the severe endothelial and muscle fibre lesions found in skeletal muscle, the endothelial cells of the heart microvasculature, are clearly more resistant to the attack of …
Dextran sulfate sodium leads to chronic colitis and pathological angiogenesis in Endoglin heterozygous mice
2010
Pathological angiogenesis is an intrinsic component of chronic intestinal inflammation, which results in remodeling and expansion of the gut microvascular bed. Endoglin is essential for endothelial cell function and physiological angiogenesis. In this study we investigated its potential role in the regulation of inflammation by testing the response of Endoglin heterozygous (Eng(+/-)) mice to experimental colitis.C57BL/6 Eng(+/-) and littermate control mice drank water supplemented with 3% dextran sulfate sodium (DSS) for 5 days and were monitored for up to 26 days for clinical signs of colitis. Inflammation, crypt damage, and angiogenic index were scored on histological sections of distal c…
Cell viability, osteoblast differentiation, and gene expression are altered in human osteoblasts from hypertrophic fracture non-unions
2007
Recent studies have provided evidence that the number and proliferation capacity of bone marrow-derived mesenchymal stem cells, as well as the number of osteoprogenitor cells are reduced in patients with fracture non-unions. For fracture non-unions that do not heal after appropriate surgical intervention, the question arises as to what extent systemic cellular dysfunctions should be considered as being pathogenetic factors. For this purpose, we have examined the hypothesis that the cell function of osteoblasts isolated from patients with fracture non-unions may differ from those of normal control individuals in an identical and controlled in vitro situation. We analyzed the osteoblast cell …
Inflammation-Induced Intussusceptive Angiogenesis in Murine Colitis
2010
Intussusceptive angiogenesis is a morphogenetic process that forms new blood vessels by the division of a single blood vessel into two lumens. Here, we show that this process of intraluminal division participates in the inflammation-induced neovascularization associated with chemically induced murine colitis. In studies of both acute (4-7 days) and chronic (28-31 days) colitis, intravital microscopy of intravascular tracers demonstrated a twofold reduction in blood flow velocity. In the acute colitis model, the decreased velocity was associated with marked dilatation of the mucosal plexus. In contrast, chronic inflammation was associated with normal caliber vessels and duplication (and trip…
Refining in vitro neurotoxicity testing--the development of blood-brain barrier models.
2003
The purpose of this paper is to review the current state of development of advanced in vitro blood–brain barrier (BBB) models. The BBB is a special capillary bed that separates the blood from the central nervous system (CNS) parenchyma. Astrocytes maintain the integrity of the BBB, and, without astrocytic contacts, isolated brain capillary endothelial cells in culture lose their barrier characteristics. Therefore, when developing in vitro BBB models, it is important to add astrocytic factors into the culture system. Recently, novel filter techniques and co-culture methods have made it possible to develop models which resemble the in vivo functions of the BBB in an effective way. With a BBB…
Preservation of glial cytoarchitecture from ex vivo human tumor and non-tumor cerebral cortical explants: A human model to study neurological diseases
2007
For the human brain, in vitro models that accurately represent what occurs in vivo are lacking. Organotypic models may be the closest parallel to human brain tissue outside of a live patient. However, this model has been limited primarily to rodent-derived tissue. We present an organotypic model to maintain intraoperatively collected human tumor and non-tumor explants ex vivo for a prolonged period of time (similar to 11 days) without any significant changes to the tissue cytoarchitecture as evidenced through immunohistochemistry and electron microscopy analyses. The ability to establish and reliably predict the cytoarchitectural changes that occur with time in an organotypic model of tumor…
Hypothetical molecular mechanisms by which local iron overload facilitates the development of venous leg ulcers and multiple sclerosis lesions.
2008
Summary This paper presents a hypothetical model of role for iron in the development of venous leg ulcers and multiple sclerosis. Elevated concentrations of iron were found in the skin affected by venous hypertension and also in the areas of brain with multiple sclerosis lesions. Individuals with hemochromatosis gene (HFE) mutations: C282Y and H63D, which result in a less efficient transport of iron by macrophages, are characterized by an increased risk for venous leg ulcer and multiple sclerosis. Multiple sclerosis is a T cell-mediated disease, and T cells probably participate in the development of venous ulcers. This deleterious role of ferric ions could be related to the regulation of T …
Immunohistochemical Detection of Hormone Receptors in Breast Carcinomas (ER-ICA, PgR-ICA): Prognostic Usefulness and Comparison with the Biochemical …
1994
In a prospective study conducted since 1983, the hormone-receptor status of primary breast carcinomas was investigated using immunohistochemical (ER-ICA, PgR-ICA) and biochemical (DCC) methods. The degree of immunohistochemical staining was evaluated according to the immunoreactive score (IRS) devised by Remmele and Stegner [Frauenarzt 28, 41-43 (1987)]. The findings obtained using the biochemical radioactive-ligand-binding assay (cutoff level, 20 fmol/mg) and those obtained using qualitative immunohistochemical methods were in agreement in 72.5% (ER-ICA) and 72.2% (PgR-ICA) of cases. For the 789 cases of primary breast carcinoma examined, postoperative data were available for a mean follow…
Use of photoplethysmography to determine gastrointestinal perfusion pressure: an experimental canine model.
2002
<i>Objectives:</i> To develop an experimental model to assess the parietal perfusion pressure (PPP) of the digestive tract using photoplethysmography. <i>Materials and Methods:</i> Twenty-two mongrel dogs were used. Progressive external compression was applied to the intestinal wall and the PPP was assessed with photoplethysmography. The study group was divided into two groups. In group 1 PPP was measured at the levels of the stomach, duodenum, jejunum and transverse colon. In group 2 PPP was measured after temporary occlusion of the truncal and marginal circulation of the jejunum to provide further variables. <i>Results:</i> The PPP decreased significant…