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Results 351 - 400 of 2241
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Karaca Melis - - 2009
BACKGROUND: The mass of pancreatic beta-cells varies according to increases in insulin demand. It is hypothesized that functionally heterogeneous beta-cell subpopulations take part in this process. Here we characterized two functionally distinct groups of beta-cells and investigated their physiological relevance in increased insulin demand conditions in rats. METHODS: Two rat ...
Best Leonard - - 2009
BACKGROUND/AIMS: Pancreatic beta-cell function is influenced by changes in cell volume. Such volume changes depend on water permeability of the plasma membrane, conferred in part by aquaporins. Islet cells express aquaporin 7 (AQP7), which is permeable to urea and glycerol in addition to water. We therefore investigated the effects of ...
Du Yi-Chieh Nancy - - 2009
It is unclear whether the cellular origin of various forms of pancreatic cancer involves transformation or transdifferentiation of different target cells or whether tumors arise from common precursors, with tumor types determined by the specific genetic alterations. Previous studies suggested that pancreatic ductal carcinomas might be induced by polyoma middle ...
Montanya Eduard - - 2009
The endocrine pancreas has a significant remodeling capacity that plays a crucial role in the maintenance of glucose homeostasis. Changes in beta-cell apoptosis, replication and size, and islet neogenesis contribute to the remodeling of the endocrine pancreas. The extent of their respective contribution varies significantly depending on the specific condition ...
Dubey Ashok K - - 2009
Amyloid-beta(Abeta42), which is known to be toxic to neuronal cells, protects yeast cells from severe sodium hydroxide toxicity. More than 85% cell death was caused by treatment with 1 mM NaOH and approximately 95% was observed at a 2 mM concentration. However, greater than 55% cells survived the treatment in ...
Russ Holger A - - 2009
BACKGROUND: In-vitro expansion of functional beta cells from adult human islets is an attractive approach for generating an abundant source of cells for beta-cell replacement therapy of diabetes. Using genetic cell-lineage tracing we have recently shown that beta cells cultured from adult human islets undergo rapid dedifferentiation and proliferate for ...
Hellemans Karine H - - 2009
Chronically elevated levels of fatty acids-FA can cause beta cell death in vitro. Beta cells vary in their individual susceptibility to FA-toxicity. Rat beta cells were previously shown to better resist FA-toxicity in conditions that increased triglyceride formation or mitochondrial and peroxisomal FA-oxidation, possibly reducing cytoplasmic levels of toxic FA-moieties. ...
Schulthess Fabienne T - - 2009
Apoptosis is a hallmark of beta-cell death in both type 1 and type 2 diabetes mellitus. Understanding how apoptosis contributes to beta-cell turnover may lead to strategies to prevent progression of diabetes. A key mediator of apoptosis, mitochondrial function, and cell survival is apoptosis inducing factor (AIF). In the present ...
Cvjetićanin Tamara - - 2009
Diabetes is characterized by progressive failure of insulin producing beta cells. It is well known that both saturated fatty acids and various products of immune cells can contribute to the reduction of beta cell viability and functionality during diabetes pathogenesis. However, their joint action on beta cells has not been ...
Bachar Etti - - 2009
Palmitate is a potent inducer of endoplasmic reticulum (ER) stress in beta-cells. In type 2 diabetes, glucose amplifies fatty-acid toxicity for pancreatic beta-cells, leading to beta-cell dysfunction and death. Why glucose exacerbates beta-cell lipotoxicity is largely unknown. Glucose stimulates mTORC1, an important nutrient sensor involved in the regulation of cellular ...
Sun Yanhong - - 2009
Beta-elemene monosubstituted amine, ether and rhenium coordinated complex were synthesized. Their structures were characterized by IR, (1)H NMR, (13)C NMR, HRMS or EA. Their IC(50) on HeLa cell lines, cell cycle and protein expression of G(1) phase (Cyclin D(1), Rb, P-Rb) were detected respectively by the method of WST-1, Flow ...
Palozza Paola - - 2009
Lycopene beta-cyclase (tlcy-b) tomatoes, obtained by modulating carotenogenesis via genetic engineering, contain a large amount of beta-carotene, as clearly visible by their intense orange colour. In the present study we have subjected tlcy-b tomatoes to an in vitro simulated digestion and analysed the effects of digestate on cell proliferation. To ...
Szabat Marta - - 2009
The enigmatic process of beta-cell maturation has significant implications for diabetes pathogenesis, and potential diabetes therapies. This study examined the dynamics and heterogeneity of insulin and pancreatic duodenal homeobox (Pdx)-1 gene expression in adult beta-cells. Insulin and Pdx1 expression were monitored in human and mouse islet cells and MIN6 cells ...
Kwon Chulan - - 2008
Despite decades of progress in cardiovascular biology, heart disease remains the leading cause of death in the developed world. Recently, cell-based therapy has emerged as a promising avenue for future therapeutics. However, the molecular signals that regulate cardiac progenitor cells are not well-understood. Wnt/beta-catenin signaling is essential for expansion and ...
Liu Hui - - 2009
Our previous studies demonstrated that nutrient regulation of mammalian target of rapamycin (mTOR) signaling promotes regenerative processes in rodent islets but rarely in human islets. Our objective was to extend these findings by using therapeutic agents to determine whether the regulation of glycogen synthase kinase-3 (GSK-3)/beta-catenin and mTOR signaling represent ...
Ariyama Yasuyo - - 2008
Low expression of antioxidant enzymes makes pancreatic beta-cells susceptible to cell damage by oxidative stress. Pancreatic beta-cell loss caused by endoplasmic reticulum stress is associated with the onset of diabetes mellitus. The present studies were undertaken to investigate a possible involvement of proapoptotic gene CHOP in pancreatic beta-cells damage by ...
Prunotto Marco - - 2009
We examined the in vitro effects of imatinib (Novartis Pharma AG, Basel, Switzerland) as a possible inhibitor of PDGFR pathway on cells derived from a recurrence of a pleural malignant solitary fibrous tumor (SFT). Primary cell culture was characterised by immunofluorescence. SFT-derived cells were treated with imatinib at different time ...
Puri Sapna - - 2009
The Vhlh gene codes for the von Hippel-Lindau protein (VHL), a tumor suppressor that is a key player in the cellular response to oxygen sensing. In humans, a germline mutation in the VHL gene leads to the von Hippel-Lindau disease, a familial syndrome characterized by benign and malignant tumors of ...
Chen R-S - - 2009
xCT, the functional subunit of the cystine/glutamate transporter xc- system, plays a critical role in the maintenance of intracellular glutathione and redox balance. Disruption of xCT significantly inhibits the growth of a variety of carcinomas, including lymphoma, glioma, prostate and breast cancer. However, the role of xCT in tumor metastasis ...
Reers Christina - - 2009
The prevalence of type 2 diabetes mellitus escalates with aging although beta-cell mass, a primary parameter of beta-cell function, is subject to compensatory regulation. So far it is unclear whether the proliferative capacity of pancreatic islets is restricted by senescence. Human pancreatic tissue from n=20 non-diabetic organ donors with a ...
Campbell-Thompson M - - 2009
AIMS/HYPOTHESIS: Recent histological analysis of pancreases obtained from patients with long-standing type 1 diabetes identified chronic islet inflammation and limited evidence suggestive of beta cell replication. Studies in rodent models also suggest that beta cell replication can be induced by certain inflammatory cytokines and by gastrin. We therefore tested the ...
Scharfmann R - - 2008
Understanding in detail how pancreatic endocrine cells develop is important for many reasons. From a scientific point of view, elucidation of such a complex process is a major challenge. From a more applied point of view, this may help us to better understand and treat specific forms of diabetes. Although ...
Halban P A - - 2008
The functional mass of beta-cells is decreased in type 2 diabetes. Replacing missing beta-cells or triggering their regeneration may thus allow for improved treatment of type 2 diabetes, to the extent that this is combined with therapy for improved insulin sensitivity. Although progress has been made in deriving beta-cell-like cells ...
Dowling Paul - - 2008
Media conditioned by dysfunctioning pancreatic beta cells offer an excellent source of potential protein markers associated with this phenotype. Proteins identified from cell culture model systems are often found to be of importance clinically. Previous work by us and others have shown that low-passage MIN-6 cells (MIN-6(L)) respond to changes ...
Kahn S E - - 2008
A characteristic and dominant feature of type 2 diabetes is a reduction in beta-cell function that is associated with a decrease in beta-cell volume. A decline in the first-phase insulin response following intravenous glucose administration can be demonstrated as the fasting glucose concentration increases. This response is completely absent before ...
Pipeleers D - - 2008
Type 1 and type 2 diabetes have often been presented as disease forms that profoundly differ in the presence and pathogenic significance of a reduced beta-cell mass. We review evidence indicating that the beta-cell mass in type 1 diabetes is usually not decreased by at least 90% at clinical onset, ...
Smolarz H D - - 2008
The chemical and pharmaceutical studies carried out on species from Polygonum L. genus showed biological activity both of the extracts and the components isolated from them. These results were the impulse to examine Polygonum amphibium L. The aim of this study was the isolation of active components from methanol extract ...
Freeby M - - 2008
The common pathology underlying both type 1 and type 2 diabetes (T1DM and T2DM) is insufficient beta-cell mass (BCM) to meet metabolic demands. An important impediment to the more rapid evaluation of interventions for both T1DM and T2DM lack of biomarkers of pancreatic BCM. A reliable means of monitoring the ...
Akirav Eitan - - 2008
Beta-cell regeneration is a fundamental but elusive goal for type 1 diabetes research. Our objective is to review newer human and animal studies of beta-cell destruction and regeneration and consider the implications for treatment of type 1 diabetes. Recent human and animal studies of beta-cell destruction and regeneration in type ...
Rupnik M - - 2009
Beta-cells in pancreatic islets form complex syncytia. Sufficient cell-to-cell electrical coupling seems to ensure coordinated depolarization pattern and insulin release that can be further modulated by rich innervation. The complex structure and coordinated action develop after birth during fast proliferation of the endocrine tissue. These emergent properties can be lost ...
Li Hongbing - - 2009
Resistance of solid tumor cells to anoikis, apoptosis induced by cell detachment from the extracellular matrix, is thought to be critical for the ability of these cells to grow anchorage independently within three-dimensional tumor masses and from metastases. Beta-catenin, a major oncoprotein, can inhibit anoikis of cancer cells via unknown ...
Meng Z X - - 2009
AIMS/HYPOTHESIS: Liver X receptors (LXRs) are important transcriptional regulators of lipid homeostasis and proliferation in several cell types. However, the roles of LXRs in pancreatic beta cells have not been fully established. The aim of this study was to investigate the effects of LXRs on pancreatic beta cell proliferation. METHODS: ...
Shiku Hitoshi - - 2009
A highly sensitive and quantitative analysis was performed using a poly(dimethylsiloxane) (PDMS) microwell array in a scanning electrochemical microscopy setup. A microelectrode with a relatively large seal radius was used to cover the top of the cylindrical PDMS microwell (96 pL). The voltammogram for 4 mM ferrocyanide resulted in a ...
Zhang Quan - - 2008
The perforated whole-cell configuration of the patch-clamp technique was applied to functionally identified beta-cells in intact mouse pancreatic islets to study the extent of cell coupling between adjacent beta-cells. Using a combination of current- and voltage-clamp recordings, the total gap junctional conductance between beta-cells in an islet was estimated to ...
Chen Wei - - 2009
It is thought that differentiation of beta-cell precursors into mature cells is largely autonomous, but under certain conditions differentiation can be modified by external factors. The factors that modify beta-cell differentiation have not been identified. In this study, we tested whether adult islet cells can affect the differentiation process in ...
Fujita Takeo - - 2008
Alteration of the tumor microenvironment by aberrant stromal cells influences many aspects of cell biology, including differentiation of stem cells and tumor metastasis. The role of transforming growth factor (TGF)-beta signaling in stromal cells of the tissue microenvironment is critical to both pathways. We examined murine marrow stromal cells with ...
Jovanovi? Milica - - 2010
Antibodies to phospholipids (aPL) have been shown to adversely affect trophoblast invasion in vivo and in vitro. HTR-8/SVneo cells derived from first trimester of pregnancy extravillous trophoblast were studied. Matrigel invasion assay, cytochemistry and cell-based enzyme-linked immunosorbant assay (ELISA) with aPL or normal IgG was used. Our data show that ...
Cnop Miriam - - 2008
The UPR (unfolded protein response) or ER (endoplasmic reticulum) stress response was first described 20 years ago. The field of ER stress has expanded tremendously since, moving from basic biology in yeast to human neurodegenerative, inflammatory, cardiovascular and neoplastic diseases. The ER stress response has also been implicated in diabetes ...
Meijer Alfred J - - 2008
Autophagy is inhibited by the insulin-amino acid-mTOR signaling pathway. Two papers in this issue of Cell Metabolism (Ebato et al., 2008; Jung et al., 2008) provide evidence that basal autophagy is necessary to maintain the architecture and function of pancreatic beta cells and that its induction in diabetic mice protects ...
Hartley Taila - - 2009
Protein degradation in eukaryotic cells is mediated primarily by the ubiquitin-proteasome system and autophagy. Turnover of protein aggregates and other cytoplasmic components, including organelles, is another function attributed to autophagy. The ubiquitin-proteasome system and autophagy are essential for normal cell function but under certain pathological conditions can be overwhelmed, which ...
Criswell Tracy L - - 2008
The transforming growth factor-beta (TGF-beta) signaling pathway plays dual roles in epithelial cell tumorigenesis. TGF-beta is initially growth inhibitory, but as tumorigenesis progresses, TGF-beta becomes prometastatic. Although the role of the types I and II TGF-beta receptors is fairly well established, the role of the ubiquitously expressed TGF-beta type III ...
Jouhilahti Eeva-Mari - - 2008
The findings of this study show that Class III beta-tubulin is a component of the mitotic spindle in multiple cell types. Class III beta-tubulin has been widely used as a neuron-specific marker, but it has been detected also in association with breast and pancreatic cancers. In this study, we describe ...
Qian Lei - - 2008
Sulfonylureas, by stimulating beta cell to secrete insulin, are still largely used for treatment of type 2 diabetic patients. More recently concern has been raised with respect to possible adverse effects associated with the use of these agents, like favoring beta cell apoptosis and beta cell exhaustion, which is believed ...
Lee Ying C - - 2009
Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been suggested to play a role in beta cell mass ...
Nolan Christopher J - - 2008
The pancreatic beta-cell senses blood nutrient levels and is modulated by neurohormonal signals so that it secretes insulin according to the need of the organism. Nutrient sensing involves marked metabolic activation, resulting in the production of coupling signals that promote insulin biosynthesis and secretion. The beta-cell's high capacity for nutrient ...
Wright Daniel G - - 2008
Peptide nucleic acid (PNA) is highly stable and binds to complementary RNA and DNA with high affinity, but it resists cellular uptake, thereby limiting its bioavailability. We investigated whether protectiveantigen (PA, a non-toxic component of anthrax toxin) could transport antisense PNA oligomers into reporter cells that contain luciferase transgenes with ...
Niu Yang P - - 2008
Beta-escin, a natural triterpenoid saponin isolated from the seed of the horse chestnut, is known to generate a wide variety of biochemical and pharmacological effects. The purpose of the present study was to examine the apoptotic and antiproliferative activity of beta-escin in HL-60 human acute myeloid leukaemia cells. Antiproliferative activity ...
Kazmierczak Anna - - 2008
alpha-Synuclein is the fundamental component of Lewy bodies which occur in the brain of 60% of sporadic and familial Alzheimer's disease patients. Moreover, a proteolytic fragment of alpha-synuclein, the so-called non-amyloid component of Alzheimer's disease amyloid, was found to be an integral part of Alzheimer's dementia related plaques. However, the ...
Suckow Arthur T - - 2008
The composition of the beta-cell exocytic machinery is very similar to that of neuronal synapses, and the developmental pathway of beta-cells and neurons substantially overlap. beta-Cells secrete gamma-aminobutyric acid and express proteins that, in the brain, are specific markers of inhibitory synapses. Recently, neuronal coculture experiments have identified three families ...
Zhou Qiao - - 2008
One goal of regenerative medicine is to instructively convert adult cells into other cell types for tissue repair and regeneration. Although isolated examples of adult cell reprogramming are known, there is no general understanding of how to turn one cell type into another in a controlled manner. Here, using a ...
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