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Cell Mass (cell + mass)
Kinds of Cell Mass Selected AbstractsSimple Measures to Monitor ,-Cell Mass and Assess Islet Graft DysfunctionAMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2007R. N. Faradji The aim of this study was to develop a simple test for the assessment of islet graft dysfunction based on measures involving fasting C-peptide. Calculations were made to account for the dependence of C-peptide secretion on glucose concentration (C-peptide/glucose ratio [CP/G]) and adjusted for renal function by calculating the C-peptide/glucose-creatinine ratio (CP/GCr). Values from 22 recipients were analyzed at different times post-last islet infusion. Receiver operating characteristic curves were used to determine which of these measures best predicts high 90-minute glucose (90 min-Glc; >10 mmol/L) after a Mixed Meal Tolerance Test (MMTT). In this initial analysis, CP/G was found to be superior predicting high 90 min-Glc with a larger area under the ROC curve than C-peptide (p = 0.01) and CP/GCr (p = 0.06). We then correlated C-peptide and CP/G with islet equivalents-IEQ/kg infused, 90 min-Glc after MMTT and clinical outcome (,-score). C-peptide and CP/G in the first 3 months post-last islet infusion correlated with IEQ/kg infused. CP/G correlated with 90 min-Glc and ,-score. C-peptide and CP/G are good indicators of islet mass transplanted. CP/G is more indicative of graft dysfunction and clinical outcome than C-peptide alone. The ease of calculation and the good correlation with other tests makes this ratio a practical tool when monitoring and managing islet transplant recipients. [source] Stability of , -carotene in spray dried preparation of Rhodotorula glutinis mutant 32JOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2003P. Bhosale Abstract Aims: To obtain , -carotene-rich dry cell preparation from mutant 32 of Rhodotorula glutinis and determination of its pigment stability. Methods and Results: The mutant 32 of R. glutinis was grown in a 14 l stirred tank fermenter. Cell mass was concentrated 10-fold by cross-flow microfiltration and then spray dried. Butylated hydroxy toluene (BHT) and d -tocopherol were used as protecting agents. A two-level, three-variable, factorial optimization was performed to achieve moisture-free, non-viable and , -carotene-rich feed additive. Conclusions: The , -carotene and cell mass in stirred tank fermenter were found to be 54 ± 5 mg l,1 and 12·8 ± 2 g l,1, respectively. In the presence of BHT, 97 ± 3% (w/w) , -carotene was recovered for all the inlet temperatures studied. The best , -carotene and yeast powder recoveries were obtained at 160°C, 11·6% (w/v) cell mass concentration and 1 g l,1 BHT. The pigments inside dried yeast powder were stable in dark and cold condition for at least 10 weeks. The purified , -carotene got almost totally denatured, under similar conditions of storage, within 76 h. Significance and Impact of the Study: Spray dried and stable preparation of , -carotene-rich yeast, R. glutinis can provide alternative source of , -carotene for use in animal nutrition. [source] Mechanisms of trophectoderm fate specification in preimplantation mouse developmentDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2010Hiroshi Sasaki During preimplantation mouse development, embryos establish two distinct cell lineages by the time of blastocyst formation: trophectoderm (TE) and inner cell mass (ICM). To explain the mechanism of this cell fate specification, two classical models, namely the inside,outside model and polarity model have been proposed based on experimental manipulation studies on embryos. This review summarizes recent findings on the molecular mechanisms of fate specification, and discusses how these findings fit into the classical models. TE development is regulated by a transcription factor cascade, the core transcription factors of which are Tead4 and Cdx2. The transcriptional activity of Tead4 is regulated by the position-dependent Hippo signaling pathway, thus supporting the inside,outside model. In contrast, several findings support the polarity model; some other findings suggest different mechanisms. We also discuss how the two classical models could be further developed in the light of recent molecular findings. [source] Morphogenetic domains in the yolk syncytial layer of axiating zebrafish embryosDEVELOPMENTAL DYNAMICS, Issue 4 2001Leonard A. D'Amico Abstract The yolk syncytial layer (YSL) of the teleostean yolk cell is known to play important roles in the induction of cellular mesendoderm, as well as the patterning of dorsal tissues. To determine how this extraembryonic endodermal compartment is subdivided and morphologically transformed during early development, we have examined collective movements of vitally stained YSL nuclei in axiating zebrafish embryos by using four-dimensional confocal microscopy. During blastulation, gastrulation, and early segmentation, zebrafish YSL nuclei display several highly patterned movements, which are organized into spatially distinct morphogenetic domains along the anterior-posterior and dorsal-ventral axes. During the late blastula period, with the onset of epiboly, nuclei throughout the YSL initiate longitudinal movements that are directed along the animal-vegetal axis. As epiboly progresses, nuclei progressively recede from the advancing margin of the epibolic YSL. However, a small group of nuclei is retained at the YSL margin to form a constricting blastoporal ring. During mid-gastrulation, YSL nuclei undergo convergent-extension behavior toward the dorsal midline, with a subset of nuclei forming an axial domain that underlies the notochord. These highly patterned movements of YSL nuclei share remarkable similarities to the morphogenetic movements of deep cells in the overlying zebrafish blastoderm. The macroscopic shape changes of the zebrafish yolk cell, as well as the morphogenetic movements of its YSL nuclei, are homologous to several morphogenetic behaviors that are regionally expressed within the vegetal endodermal cell mass of gastrulating Xenopus embryos. In contrast to the cellular endoderm of Xenopus, the dynamics of zebrafish YSL show that a syncytial endodermal germ layer can express a temporal sequence of morphogenetic domains without undergoing progressive steps of cell fate restriction. © 2001 Wiley-Liss, Inc. [source] The role of autophagy in , -cell lipotoxicity and type 2 diabetesDIABETES OBESITY & METABOLISM, Issue 2010G. Las Autophagy, a ubiquitous catabolic pathway involved in both cell survival and cell death, has been implicated in many age-associated diseases. Recent findings have shown autophagy to be crucial for proper insulin secretion and , -cell viability. Transgenic mice lacking autophagy in their , -cells showed decreased , -cell mass and suppressed glucose-stimulated insulin secretion. Several studies showed that stress can stimulate autophagy in , -cells: the number of autophagosomes is increased in different in vivo models for diabetes, such as db/db mice, mice fed high-fat diet, pdx-1 knockout mice, as well as in in vitro models of glucotoxicity and lipotoxicity. Pharmacological and molecular inhibition of autophagy increases the susceptibility to cell stress, suggesting that autophagy protects against diabetes-relevant stresses. Recent findings, however, question these conclusions. Pancreases of diabetics and , -cells exposed to fatty acids show accumulation of abnormal autophagosome morphology and suppression of lysosomal gene expression suggesting impairment in autophagic turnover. In this review we attempt to give an overview of the data generated by others and by us in view of the possible role of autophagy in diabetes, a role which depending on the conditions, could be beneficial or detrimental in coping with stress. [source] Exendin-4 protects pancreatic beta cells from human islet amyloid polypeptide-induced cell damage: potential involvement of AKT and mitochondria biogenesisDIABETES OBESITY & METABOLISM, Issue 9 2010R. Fan Aim: Glucagon-like peptide-1 (GLP-1) stimulates beta-cell proliferation and enhances beta-cell survival, whereas oligomerization of human islet amyloid polypeptide (hIAPP) may induce beta-cell apoptosis and reduce beta-cell mass. Type 2 diabetes is associated with increased expression of IAPP. As GLP-1-based therapy is currently developed as a novel antidiabetic therapy, we examined the potential protective action of the GLP-1 receptor agonist exendin-4 on hIAPP-induced beta-cell apoptosis. Methods: The study was performed in clonal insulinoma (INS-1E) cells. Both method of transcriptional and translational and sulphorhodamine B (SRB) assays were used to evaluate cell viability and cell mass. Western blot analysis was applied to detect protein expression. Transfection of constitutively active protein kinase B (PKB/AKT) was performed to examine the role of AKT. Mitochondrial biogenesis was quantified by mitogreen staining and RT-PCR. Results: First, we confirmed that hIAPP induced cell apoptosis and growth inhibition in INS-1E cells. These effects were partially protected by exendin-4 in association with partial recovery of the hIAPP-mediated AKT inhibition. Furthermore, AKT constitutive activation attenuated hIAPP-induced apoptosis, whereas PI3K/AKT inhibition abrogated exendin-4-mediated effects. These findings suggest that the antiapoptotic and proliferative effects of exendin-4 in hIAPP-treated INS-1E cells were partially mediated through AKT pathway. Moreover, hIAPP induced FOXO1 but inhibited pdx-1 nucleus translocation. These effects were restored by exendin-4. Finally, mitogreen staining and RT-PCR revealed enhanced mitochondrial biogenesis by exendin-4 treatment. Conclusions: Collectively, these results suggest that GLP-1 receptor agonist protects beta cells from hIAPP-induced cell death partially through the activation of AKT pathway and improved mitochondrial function. [source] GLP-1: physiological effects and potential therapeutic applicationsDIABETES OBESITY & METABOLISM, Issue 11 2008Kasper Aaboe Glucagon-like peptide 1 (GLP-1) is a gut-derived incretin hormone with the potential to change diabetes. The physiological effects of GLP-1 are multiple, and many seem to ameliorate the different conditions defining the diverse physiopathology seen in type 2 diabetes. In animal studies, GLP-1 stimulates ,-cell proliferation and neogenesis and inhibits ,-cell apoptosis. In humans, GLP-1 stimulates insulin secretion and inhibits glucagon and gastrointestinal secretions and motility. It enhances satiety and reduces food intake and has beneficial effects on cardiovascular function and endothelial dysfunction. Enhancing incretin action for therapeutic use includes GLP-1 receptor agonists resistant to degradation (incretin mimetics) and dipeptidyl peptidase (DPP)-4 inhibitors. In clinical trials with type 2 diabetic patients on various oral antidiabetic regimes, both treatment modalities efficaciously improve glycaemic control and ,-cell function. Whereas the incretin mimetics induce weight loss, the DPP-4 inhibitors are considered weight neutral. In type 1 diabetes, treatment with GLP-1 shows promising effects. However, several areas need clinical confirmation: the durability of the weight loss, the ability to preserve functional ,-cell mass and the applicability in other than type 2 diabetes. As such, long-term studies and studies with cardiovascular end-points are needed to confirm the true benefits of these new classes of antidiabetic drugs in the treatment of diabetes mellitus. [source] Pancreatic ,-cell mass or ,-cell function?DIABETES OBESITY & METABOLISM, Issue 2008That is the question! First page of article [source] VMAT2 quantitation by PET as a biomarker for ,-cell mass in health and diseaseDIABETES OBESITY & METABOLISM, Issue 2008M. Freeby The common pathology underlying both type 1 and type 2 diabetes (T1DM and T2DM) is insufficient ,-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 mass and/or function of ,-cells would enable evaluation of the progression of diabetes as well as the monitoring of pharmacologic and other interventions. Recently, we identified a biomarker of BCM that is quantifiable by positron emission tomography (PET). PET is an imaging technique which allows for non-invasive measurements of radioligand uptake and clearance, is sensitive in the pico- to nanomolar range and of which the results can be deconvoluted into measurements of receptor concentration. For BCM estimates, we have identified VMAT2 (vesicular monoamine transporter type 2) as a biomarker and [11C] DTBZ (dihydrotetrabenazine) as the transporter's ligand. VMAT2 is highly expressed in ,-cells of the human pancreas relative to other cells of the endocrine and exocrine pancreas. Thus measurements of [11C] DTBZ in the pancreas provide an indirect measurement of BCM. Here we summarize our ongoing efforts to validate the clinical utility of this non-invasive approach to real-time BCM measurements [source] Efforts to develop methods for in vivo evaluation of the native ,-cell massDIABETES OBESITY & METABOLISM, Issue 2008S. Schneider Visualization and quantification of the native ,-cell mass in vivo in humans appear to be important in the study of the natural course of diabetes, and in ongoing trials aimed at preserving ,-cell mass in patients with diabetes. This cannot be done by biopsy sampling, and therefore there is a great need for development of a non-invasive method. This article discusses the principle theoretical requirements for reaching this goal. In addition, it provides an overview of tracer probes, which have been examined as potential ,-cell mass imaging agents in the past. Finally, some future perspectives are discussed. [source] New prospects for immunotherapy at diagnosis of type 1 diabetesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 4 2009Paolo Pozzilli Immune intervention at diagnosis of type 1 diabetes (T1D) aims to prevent or reverse the disease by blocking autoimmunity, thereby preserving/restoring ,-cell mass and function. Recent clinical trials of non-specific and of antigen-specific immune therapies have demonstrated the feasibility of modulation of islet-specific autoimmunity in patients with partial prevention of loss of insulin secretion. In a series of review articles published in this issue of the journal, some of the most promising approaches of immune intervention in T1D are presented. Here we outline the rationale of such interventions and future prospects in this area. Copyright © 2009 John Wiley & Sons, Ltd. Insulin therapy in type 1 diabetes (T1D) rescues the patient from a certain death but not cure the disease. The goal of any therapeutic intervention in T1D is the preservation of insulin-secreting cells; this is achieved by the abrogation of pathogenic reactivity to beta cell autoantigens while preserving full capacity to generate a normal immune response against foreign antigens. Although several therapeutic candidates have been investigated in experimental models of T1D many of which showed promising results, a successful extrapolation of these findings to human T1D has proved to be difficult. In part, this failure results from the considerable disease heterogeneity associated with diverse genetic and non-genetic disease determinants and the spectrum of clinical phenotype at diagnosis. Thus, a younger age at onset is associated with stronger genetic susceptibility, more intense immune response to ,-cell antigens, shorter duration of symptoms, more severe metabolic derangement at diagnosis and a more rapid rate of ,-cell-destruction 1,3. Therefore, designing therapies that would be effective in all clinical settings is definitely challenging. In this issue five different approaches are discussed ranging from antigen-specific therapies [DiaPep277 and glutamic acid decarboxylase(GAD)], to non-antigen-specific immunoregulation (anti-CD3) and to anti-inflammatory (anti-IL1 receptor antagonist). These approaches are currently being tested in large international multicenter trials, and all of them use very similar outcome in terms of a beneficial effect (C-peptide secretion as evidence of a therapeutic effect on restoration of ,-cell function). The authors have been asked to follow a similar format in presenting their approaches so that the reader can easily compare them in terms of rationale and therapeutic goals. [source] The role of insulin-like growth factor-I and its binding proteins in glucose homeostasis and type 2 diabetesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 1 2009Swapnil N. Rajpathak Abstract This review addresses the possible role of the insulin-like growth factor (IGF)-axis in normal glucose homoeostasis and in the etiopathogenesis of type 2 diabetes. IGF-I, a peptide hormone, shares amino acid sequence homology with insulin and has insulin-like activity; most notably, the promotion of glucose uptake by peripheral tissues. Type 2 diabetes as well as pre-diabetic states, including impaired fasting glucose and impaired glucose tolerance, are associated cross-sectionally with altered circulating levels of IGF-I and its binding proteins (IGFBPs). Administration of recombinant human IGF-I has been reported to improve insulin sensitivity in healthy individuals as well as in patients with insulin resistance and type 2 diabetes. Further, IGF-I may have beneficial effects on systemic inflammation, a risk factor for type 2 diabetes, and on pancreatic ,-cell mass and function. There is considerable inter-individual heterogeneity in endogenous levels of IGF-I and its binding proteins; however, the relationship between these variations and the risk of developing type 2 diabetes has not been extensively investigated. Large prospective studies are required to evaluate this association. Copyright © 2009 John Wiley & Sons, Ltd. [source] Progenitor cells in the adult pancreasDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 1 2004Andrew M. Holland Abstract The ,-cell mass in the adult pancreas possesses the ability to undergo limited regeneration following injury. Identifying the progenitor cells involved in this process and understanding the mechanisms leading to their maturation will open new avenues for the treatment of type 1 diabetes. However, despite steady advances in determining the molecular basis of early pancreatic development, the identification of pancreatic stem cells or ,-cell progenitors and the molecular mechanisms underlying ,-cell regeneration remain unclear. Recent advances in the directed differentiation of embryonic and adult stem cells has heightened interest in the possible application of stem cell therapy in the treatment of type 1 diabetes. Drawing on the expanding knowledge of pancreas development, ,-cell regeneration and stem cell research, this review focuses on progenitor cells in the adult pancreas as a potential source of ,-cells. Copyright © 2004 John Wiley & Sons, Ltd. [source] Molecular insights into insulin action and secretionEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2002C. J. Rhodes Abstract Tightly co-ordinated control of both insulin action and secretion is required in order to maintain glucose homeostasis. Gene knockout experiments have helped to define key signalling molecules that affect insulin action, including insulin and insulin-like growth factor-1 (IGF-1) receptors, insulin receptor substrate (IRS) proteins and various downstream effector proteins. ,-cell function is also a tightly regulated process, with numerous factors (including certain signalling molecules) having an impact on insulin production, insulin secretion and ,-cell mass. While signalling molecules play important roles in insulin action and secretion under normal circumstances, abnormal insulin signalling in muscle, adipose tissue, liver and pancreas leads to insulin resistance and ,-cell dysfunction. In particular, the signalling protein IRS-2 may have a central role in linking these abnormalities, although other factors are likely to be involved. [source] Cell autonomous sorting and surface positioning in the formation of primitive endoderm in embryoid bodies,GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 6 2007Malgorzata E. Rula Abstract The differentiation and formation of the primitive endoderm in early embryos can be mimicked in vitro by the aggregation of embryonic stem cells to form embryoid bodies. We present morphological evidence that primitive endoderm cells often first locate in the interior of embryoid bodies and subsequently migrate to the surface. Cell mixing experiments indicate that surface positioning is an intrinsic property of endoderm epithelial cells. Moreover, Disabled-2 (Dab2) is required for surface sorting and positioning of the endoderm cells: when Dab2 expression was eliminated, the differentiated endoderm epithelial cells distributed throughout the interior of the embryoid bodies. Surprisingly, E-cadherin is dispensable for primitive endoderm differentiation and surface sorting in embryoid bodies. These results support the model that primitive endoderm cells first emerge in the interior of the inner cell mass and are subsequently sorted to the surface to form the primitive endoderm. genesis 45: 327,338, 2007. Published 2007 Wiley-Liss, Inc. [source] The effect of carbon and nitrogen sources on bovicin HC5 production by Streptococcus bovis HC5JOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2009A.A.T. De Carvalho Abstract Aims:, To investigate the effect of media composition and agroindustrial residues on bovicin HC5 production by Streptococcus bovis HC5. Methods and Results:, Batch cultures of S. bovis HC5 were grown in basal medium containing different carbon and nitrogen sources. The activity of cell-free and cell-associated bovicin HC5 was determined in culture supernatants and acidic extracts obtained from cell pellets, respectively. Streptococcus bovis HC5 produced bovicin using a variety of carbon and nitrogen sources. The highest specific activity was obtained in media containing 16 g l,1 of glucose, after 16 h of incubation. The peak in cell-free and cell-associated bovicin HC5 activity was detected when S. bovis HC5 cultures reached stationary phase. The bovicin HC5 specific activity and bacterial cell mass increased approximately 3-fold when yeast extract and trypticase (0·5 and 1·0 g l,1, respectively) were added together to the basal medium. Streptococcus bovis HC5 cultures produced bovicin HC5 in cheese whey and sugar cane juice and maximal volumetric productivity was obtained after 12 h of incubation. Conclusions:,Streptococcus bovis HC5 is a versatile lactic acid bacterium that can utilize several carbon and nitrogen sources for bovicin HC5 production. This bacterium could be a useful model to study bacteriocin production in the rumen ecosystem. Significance and Impact of the Study:, The use of agroindustrial residues as carbon sources could have an economical impact on bovicin HC5 production. To our knowledge, this is the first report to show the use of sugar cane juice for bacteriocin production by lactic acid bacteria. [source] Efficient removal of hexavalent chromium by a tolerant Streptomyces sp. affected by the toxic effect of metal exposureJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007D.K. Morales Abstract Aims:, To isolate and analyse chromium-resistant micro-organisms suitable for bioremediation. Methods and Results:, Strain CG252, with a minimal inhibitory concentration of 500 ,g ml,1, was isolated from contaminated soils and identified as a Streptomyces sp. by 16S rDNA sequence analysis. Assays carried out at various Cr(VI) concentrations indicated that chromium removal was more efficient at lower concentrations and that this activity resulted in accumulation of Cr(III). Atomic adsorption analysis indicated that the chromium removed was not associated with cell mass and activity assays showed that the capacity to reduce Cr(VI) was most probably due to a soluble cytosolic enzyme. Cells grown as biofilms showed enhanced removal of Cr(VI) with respect to planktonic cells, while analysis of growth and colony morphology indicated that Cr(VI) had a toxic effect on this strain. Conclusions:,Streptomyces sp. CG252 tolerated heavy metals and elevated levels of chromium, despite its negative effect on growth and development, and was efficient at removing Cr(VI) by promoting reduction to Cr(III). Significance and Impact of the Study:, Strain CG252's capacity to tolerate heavy metals and to reduce Cr(VI) to the less toxic Cr(III), especially when forming biofilms, makes it a promising candidate for detoxification of sites containing this heavy metal. [source] Stability of , -carotene in spray dried preparation of Rhodotorula glutinis mutant 32JOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2003P. Bhosale Abstract Aims: To obtain , -carotene-rich dry cell preparation from mutant 32 of Rhodotorula glutinis and determination of its pigment stability. Methods and Results: The mutant 32 of R. glutinis was grown in a 14 l stirred tank fermenter. Cell mass was concentrated 10-fold by cross-flow microfiltration and then spray dried. Butylated hydroxy toluene (BHT) and d -tocopherol were used as protecting agents. A two-level, three-variable, factorial optimization was performed to achieve moisture-free, non-viable and , -carotene-rich feed additive. Conclusions: The , -carotene and cell mass in stirred tank fermenter were found to be 54 ± 5 mg l,1 and 12·8 ± 2 g l,1, respectively. In the presence of BHT, 97 ± 3% (w/w) , -carotene was recovered for all the inlet temperatures studied. The best , -carotene and yeast powder recoveries were obtained at 160°C, 11·6% (w/v) cell mass concentration and 1 g l,1 BHT. The pigments inside dried yeast powder were stable in dark and cold condition for at least 10 weeks. The purified , -carotene got almost totally denatured, under similar conditions of storage, within 76 h. Significance and Impact of the Study: Spray dried and stable preparation of , -carotene-rich yeast, R. glutinis can provide alternative source of , -carotene for use in animal nutrition. [source] Programming the genome in embryonic and somatic stem cellsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2007Philippe Collas ,,Introduction ,,Epigenetic makeup of embryonic stem cells: keeping chromatin loose -,DNA methylation and gene expression -,CpG methylation profiles in mouse ESCs -,CpG methylation patterns in human ESCs -,Both active and inactive histone modification marks on developmentally regulated genes in ESCs suggest transcriptional activation potential -,A regulatory role of histone H1 in gene expression in embryonic stem cells? -,Polycomb group proteins impose a transcriptional brake on lineage-priming genes ,,The epigenetic makeup of mesenchymal stem cells reflects restricted differentiation potential -,CpG methylation patterns on lineage-specific promoters in adipose stem cells -,CpG content affects the relationship between promoter DNA methylation and transcriptional activity -,Bivalent histone modifications on potentially active genes? ,,Linking DNA methylation to histone modifications, chromatin packaging and (re)organization of the nuclear compartment ,,Perspectives: towards remodelling the stem cell epigenome? Abstract In opposition to terminally differentiated cells, stem cells can self-renew and give rise to multiple cell types. Embryonic stem cells retain the ability of the inner cell mass of blastocysts to differentiate into all cell types of the body and have acquired in culture unlimited self-renewal capacity. Somatic stem cells are found in many adult tissues, have an extensive but finite lifespan and can differentiate into a more restricted array of cell types. A growing body of evidence indicates that multi-lineage differentiation ability of stem cells can be defined by the potential for expression of lineage-specification genes. Gene expression, or as emphasized here, potential for gene expression, is largely controlled by epigenetic modifications of DNA and chromatin on genomic regulatory and coding regions. These modifications modulate chromatin organization not only on specific genes but also at the level of the whole nucleus; they can also affect timing of DNA replication. This review highlights how mechanisms by which genes are poised for transcription in undifferentiated stem cells are being uncovered through primarily the mapping of DNA methylation, histone modifications and transcription factor binding throughout the genome. The combinatorial association of epigenetic marks on developmentally regulated and lineage-specifying genes in undifferentiated cells seems to define a pluripotent state. [source] Red cell exchange transfusion for babesiosis in Rhode IslandJOURNAL OF CLINICAL APHERESIS, Issue 3 2009Joshua Spaete Abstract We report four cases of clinically severe tick borne babesiosis treated with chemotherapy and adjunctive red cell exchange (RCE) at two Rhode Island hospitals from 2004 to 2007. All RCE procedures were performed using a Cobe Spectra device and were well tolerated without complications. The volume of allogeneic red cells used in the exchange was determined using the algorithm in the apheresis device with the input variables of preprocedure hematocrit, weight, height, an assumed allogeneic red cell hematocrit of 55 and a desired post procedure hematocrit of 27. The preprocedure level of parasitemia varied between 2.4% and 24% and the postprocedure level of parasitemia between 0.4 and 5.5% with an average overall percent reduction in parasitemia of 74%. Retrospectively, application of a new formula to calculate red cell mass appeared to correlate better with the percent reduction in parasitemia. Previous reports of RCE in babesiosis were reviewed. The reported reduction in parasitemia varied from 50% to >90%. Although a preprocedure level of parasitemia of 10% is sometimes used as a threshold for RCE in clinically severe babesiosis, this threshold does not have a firm empirical basis. No postprocedure desired level of parasitemia is indicated nor the mass of allogeneic red cells needed to achieve such a level. We conclude that current estimates of the dose of allogeneic red cells used in RCE are probably inaccurate, advocate a new formula to estimate this dose and suggest that a 90% reduction in parasitemia should be the minimally desired target of RCE in babesiosis. J. Clin. Apheresis, 2009. © 2009 Wiley-Liss, Inc. [source] Autologous peripheral blood stem cell collections in children weighing less than 10 Kg with solid tumors: Experience of a single centerJOURNAL OF CLINICAL APHERESIS, Issue 2 2005Hyun-Jung Cho Abstract There have only been a few reports and limited performance of peripheral blood stem cell (PBSC) collection in very small children weighing less than 10 kg. In this study, we intended to evaluate the safety and yield of PBSC collection, with the efficacy of PBSC transplantation (PBSCT) in the smallest children with solid tumors. From January 1998 to February 2004, 173 children underwent PBSC collection in Samsung Medical Center, Korea. Of these, 15 (8.7%) children weighed less than 10 kg and their clinical diagnoses were neuroblastoma (10 cases), rhabdoid tumor (2 cases), rhabdomyosarcoma (2 cases), and Wilms tumor (1 case). PBSCs were collected following chemotherapy plus G-CSF mobilization. The median age and weight at the time of apheresis were 15 months and 9 kg, respectively. The median number of PBSC collection procedures per case was 4 (range, 2,7). The median cell yield per apheresis product was 0.95 (range, 0.01,33.32) × 106/kg CD34+ cells and 1.96 (range, 0.12,23.39) × 108/kg mononuclear cells. No complications associated with citrate toxicity and other adverse effect were observed during the procedures. After high-dose chemotherapy, 14 patients were reinfused with PBSCs alone and all showed successful hematopoietic recovery. We concluded that PBSC collection would be a safe and practical procedure, even when done in the smallest children, provided that adequate intravascular fluid volume and circulating red cell mass were maintained. Also, the use of PBSCs to support high-dose chemotherapy was well tolerated and might enhance hematological recovery in the smallest children showing the excellent efficacy of PBSCT. J. Clin. Apheresis © 2005 Wiley-Liss, Inc. [source] Mitochondrial function and apoptotic susceptibility in aging skeletal muscleAGING CELL, Issue 1 2008Béatrice Chabi Summary During aging, skeletal muscle undergoes sarcopenia, a condition characterized by a loss of muscle cell mass and alterations in contractile function. The origin of these decrements is unknown, but evidence suggests that they can be partly attributed to mitochondrial dysfunction. To characterize the nature of this dysfunction, we investigated skeletal muscle contractile properties, subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondrial biogenesis and function, as well as apoptotic susceptibility in young (6 months old) and senescent (36 months old) Fischer 344 Brown Norway rats. Muscle mass and maximal force production were significantly lower in the 36-month group, which is indicative of a sarcopenic phenotype. Furthermore, contractile activity in situ revealed greater fatigability in the 36-month compared to the 6-month animals. This decrement could be partially accounted for by a 30% lower mitochondrial content in fast-twitch muscle from 36-month animals, as well as lower protein levels of the transcriptional coactivator peroxisome proliferator-activated receptor , coactivator-1,. Enzyme activities and glutamate-induced oxygen consumption rates in isolated SS and IMF mitochondria were similar between age groups. However, mitochondrial reactive oxygen species (ROS) production during state 3 respiration was ~1.7-fold greater in mitochondria isolated from 36-month compared to 6-month animals, and was accompanied by a 1.8-fold increase in the DNA repair enzyme 8-oxoguanine glycosylase 1 in fast-twitch muscle. Basal rates of release of cytochrome c and endonuclease G in SS mitochondria were 3.5- to 7-fold higher from senescent animals. These data suggest that the age-related sarcopenia and muscle fatigability are associated with enhanced ROS production, increased mitochondrial apoptotic susceptibility and reduced transcriptional drive for mitochondrial biogenesis. [source] Cellular origins of ,-cell regeneration: a legacy view of historical controversiesJOURNAL OF INTERNAL MEDICINE, Issue 4 2009A. Granger Abstract. Beta-cell regeneration represents a major goal of therapy for diabetes. Unravelling the origin of , cells during pancreatic regeneration could help restore a functional ,-cell mass in diabetes patients. This scientific question has represented a longstanding interest still intensively investigated today. This review focuses on pioneering observations and subsequent theories made 100 years ago and describes how technical innovation helped resolve some, but not all, of the controversies generated by these early investigators. At the end of the 19th century, complete pancreatectomy demonstrated the crucial physiological role of the pancreas and its link with diabetes. Pancreatic injury models, including pancreatectomy and ductal ligation, allowed investigators to describe islet function and to assess the regenerative capacity of the pancreas. Three main theories were proposed to explain the origins of newly formed islets: (i) transdifferentiation of acinar cells into islets, (ii) islet neogenesis, a process reminiscent of islet formation during embryonic development, and (iii) replication of preexisting islet cells. Despite considerable technical innovation in the last 50 years, the origin of new adult , cells remains highly controversial and the same three theories are still debated today. [source] Comparative morphology of the foot structure of four genera of Loxosomatidae (Entoprocta): Implications for foot functions and taxonomyJOURNAL OF MORPHOLOGY, Issue 10 2010Tohru Iseto Abstract Entoprocta is a group of mostly cryptic, benthic invertebrates with a sedentary lifestyle. Here, we investigate the morphology of the entoproct foot, which is an important structure in attachment and locomotion. We describe the foot structure of four solitary entoprocts, Loxosoma monilis, Loxosomella stomatophora, Loxocorone allax, and Loxomitra mizugamaensis, by means of light and transmission electron microscopy. Gland cells containing secretory granules were found in the foot of all the four species. In L. monilis, the gland cells densely paved the underside of the disc-shaped foot, but no duct or groove was found. In L. stomatophora and L. allax, a foot gland was present at the frontal end of a foot groove. The foot gland was a solid cell mass in the former species but a sac-like structure in the latter. Two types of groove accessory cells were recognized in both species; groove bulge cells (GBCs) showed large cytoplasmic bulges extending into the groove lumen, while groove microvillus cells have microvillus mats in the lateral wall of the groove. The bulges of GBCs in L. stomatophora are slender and attached to one another with desmosomes, forming appendages that extend down to the substratum, hinting at their contribution to attachment and locomotion. The bulges in L. allax form large swellings that fill the groove lumen and are connected to the surrounding cells with hemidesmosomes. In the liberated buds of L. mizugamaensis, tripartite gland cell masses were found at the basal end of the stalk, but no groove was found. A small invagination, which may be the opening of the gland, was found at the center of the foot tip, where the liberated buds attach themselves to the substratum and then metamorphose into adults. No openings were found at the lateral terminal wings, which support locomotion in Loxomitra species. J. Morphol. 271:1185,1196, 2010. © 2010 Wiley-Liss, Inc. [source] Protective role of COMP-Ang1 in ischemic rat brainJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2010Hye Young Shin Abstract In cerebral ischemia, the induction of angiogenesis may represent a natural defense mechanism that enables the hypoxic brain to avoid progression into infarction. Angiopoietin-1 (Ang1) is known to produce non-leaky and stable blood vessel formation mainly by the Tie2 receptor. Therefore, we envisioned that the application of cartilage oligomeric matrix protein-Ang1 (COMP-Ang1), a soluble, stable, and potent form of Ang1, would promote angiogenesis and provide a protective effect following unilateral middle cerebral artery occlusion (MCAO) in rats. To this end, we employed a 2-hour-MCAO model, and treated rats with adenovirus encoding COMP-Ang1 (Ade-COMP-Ang1) or control virus encoding ,-gal (Ade-,-gal). Time course magnetic resonance images (MRIs) revealed significantly reduced infarct volume in the rats treated with Ade-COMP-Ang1 with an improvement of post-ischemic neurological deficits compared with rats treated with Ade-,-gal. Moreover, compared to the rats treated with Ade-,-gal, the rats treated with Ade-COMP-Ang1 showed an increase in blood vessels, especially in the border zone adjacent to the infarction, increased number of endogenous neuronal progenitor cells in the ischemic brain, and decreased number of TUNEL-positive cells. Taken together, COMP-Ang1 reduced infarct volume and consequently attenuated post-ischemic neurological deficits through enhanced angiogenesis and increased viable cell mass of neuronal cells. © 2009 Wiley-Liss, Inc. [source] General hybrid multizonal/CFD approach for bioreactor modelingAICHE JOURNAL, Issue 8 2003F. Bezzo A critical issue in the modeling of aerobic bioreactors is the close interaction between fluid flow and the biological reactions. In particular, shear rate has a large effect on the broth viscosity which, in turn, affects the rate of mass transfer of oxygen from the gas to the liquid phase. We demonstrate how a generic hybrid multizonal/computational fluid dynamics (CFD) modeling approach can be applied to take account of these interactions. The approach to multizonal modeling presented characterizes the flow rates between adjacent zones, and also the fluid mechanical quantities, such as the shear stress, that have important effects on the process behavior within each zone, by means of steady-state CFD calculations. An unstructured model for xanthan gum production in a batch aerobic bioreactor is used for this purpose. The hybrid modeling approach is also applied to structured models involving distributions of cell mass within each zone. [source] Improved approach for transferring and cultivating Methanosarcina acetivorans C2A (DSM 2834)LETTERS IN APPLIED MICROBIOLOGY, Issue 6 2009H. Summer Abstract Aim:, A method for cultivating Methanosarcina acetivorans was further developed to handle these anaerobic archaea without special equipment such as an anaerobic chamber. Methods and Results:, Medium was filtered and oxygen removed under a nitrogen gas-phase. A dithiothreitol-filled syringe was used to transfer cells from high density grown cultures to new medium. Growth time and cell mass were determined, as well as cell viability was proven by light microscopy. Conclusion:, Cell transfer and growth was successful using this approach. Significance and Impact of the Study:, This updated technique allows almost every laboratory the opportunity to grow these methanogenic organisms for further studies. The described method could be used for proteomic analysis and is also interesting for further protein structure determination. [source] Generation of hepatocytes from cultured mouse embryonic stem cellsLIVER TRANSPLANTATION, Issue 10 2003Xiao Ling Kuai Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of fertilized blastocysts in vitro. ES cells can be induced to undergo differentiation into potentially all cell types. The aim of this study is to examine the differentiating potential of mouse ES cells into hepatocytes in the presence of retinoic acid (RA), hepatocyte growth factor (HGF), and ,-nerve growth factor (,-NGF). RA, HGF, and ,-NGF were added to the cell culture. Hepatocyte induction was confirmed morphologically, as well as biochemically, through immunohistochemical assays of ,1 -antitrypsin (,1 -AT) and alfafetaprotein (AFP) expression and reverse-transcriptase polymerase chain reaction tests for the presence of albumin, transthyretin, glucose 6 phosphates, hepatic nuclear factor 4, and SAPK/ERK kinase-1 (SEK1) messenger RNA, produced only by functioning hepatocytes. Fifteen days after the addition of HGF and ,-NGF to the cell culture, many epithelioid cells were noticed. ,1 -AT, AFP, albumin, transthyretin, glucose 6 phosphates, hepatic nuclear factor 4, and SEK1 messenger RNA expression also was detected, indicating successful ES cell differentiation into functioning hepatocytes. However, in the presence of RA alone, only transthyretin messenger RNA was positive, whereas no other expression pertaining to functioning hepatocytes could be detected. In the presence of HGF and ,-NGF, mouse ES cells can differentiate into functioning hepatocytes, whereas RA function is limited. [source] Expression of the inulinase gene from the marine-derived Pichia guilliermondii in Saccharomyces sp.MICROBIAL BIOTECHNOLOGY, Issue 5 2010ethanol production from inulin Summary It has been confirmed that Saccharomyces sp. W0 can produce high concentration of ethanol. In this study, the INU1 gene cloned from the marine-derived Pichia guilliermondii was transformed into uracil mutant of Saccharomyces sp. W0. The positive transformant Inu-66 obtained could produce 34.2 U ml,1 of extracellular inulinase within 72 h of cultivation. It was found that 15.2 U of inulinase activity per one gram of inulin was suitable for inulin hydrolysis and ethanol production by the transformant Inu-66. During the small-scale fermentation, 13.7 ml of ethanol in 100 ml of medium was produced and 99.1% of the added inulin was utilized by the transformant. During the 2 l fermentation, 14.9% (v/v) of ethanol was produced from inulin and 99.5% of the added inulin was converted into ethanol, CO2 and cell mass. [source] A cellular level approach to predicting resting energy expenditure: Evaluation of applicability in adolescents,AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2010ZiMian Wang We previously derived a cellular level approach for a whole-body resting energy expenditure (REE) prediction model by using organ and tissue mass measured by magnetic resonance imaging (MRI) combined with their individual cellularity and assumed stable-specific resting metabolic rates. Although this approach predicts REE well in both young and elderly adults, there were no studies in adolescents that specifically evaluated REE in relation to organ,tissue mass. It is unclear whether the approach can be applied to rapidly growing adolescents. The aim of the present study was to evaluate the applicability of the previous developed REE prediction model in adolescents, and to compare its applicability in young and elderly adults. Specifically, we tested the hypothesis that measured REE can be predicted from a combination of individual organ and tissue mass and their related cellularity. This was a 2-year longitudinal investigation. Twenty healthy male subjects with a mean age of 14.7 years had REE, organ and tissue mass, body cell mass, and fat-free mass (FFM) measured by indirect calorimetry, whole-body MRI, whole-body 40K counting and dual-energy X-ray absorptiometry, respectively. The predicted REE (REEp; mean ± SD, 1,487 ± 238 kcal/day) was correlated with the measured REE (REEm, 1,606 ± 237 kcal/day, r = 0.76, P < 0.001). The mean difference (118 ± 165 kcal/day) between REEm and REEp was significant (P = 0.0047), accounting for 7.3% of REEm for the entire group. The present study, the first of its type in adolescents, does not support the applicability of the organ,tissue-based REE prediction model during rapid adolescent growth. A modified general REE prediction model is thus suggested which may account for the higher REE/FFM ratio observed in adolescents. Am. J. Hum. Biol. 2010. © 2010 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||