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Regeneration Process (regeneration + process)
Selected AbstractsEffects of eccentric treadmill running on mouse soleus: degeneration/regeneration studied with Myf-5 and MyoD probesACTA PHYSIOLOGICA, Issue 1 2003A.-S. Armand Abstract Aim:, The aim of this report is to show that eccentric exercise under well-controlled conditions is an alternative model, to chemical and mechanical analyses, and analyse the process of degeneration/regeneration in mouse soleus. Methods:, For this, mice were submitted to a single bout of eccentric exercise on a treadmill down a 14° decline for 150 min and the soleus muscle was analysed at different times following exercise by histology and in situ hybridization in comparison with cardiotoxin-injured muscles. Results:, We analyse the regenerative process by detection of the accumulation of transcripts coding for the two myogenic regulatory factors, Myf-5 and MyoD, which are good markers of the activated satellite cells. From 24 h post-exercise (P-E), clusters of mononucleated Myf-5/MyoD-positive cells were detected. Their number increased up to 96 h P-E when young MyoD-positive myotubes with central nuclei began to appear. From 96 to 168 h P-E the number of myotubes increased, about 10-fold, the new myotubes representing 58% of the muscle cells (168 h P-E). Conclusion:, These results show that this protocol of eccentric exercise is able to induce a drastic degeneration/regeneration process in the soleus muscle. This offers the opportunity to perform biochemical and molecular analyses of a process of regeneration without muscle environment defects. The advantages of this model are discussed in the context of fundamental and therapeutical perspectives. [source] Localized delivery of growth factors for periodontal tissue regeneration: Role, strategies, and perspectives,MEDICINAL RESEARCH REVIEWS, Issue 3 2009Fa-Ming Chen Abstract Difficulties associated with achieving predictable periodontal regeneration, means that novel techniques need to be developed in order to regenerate the extensive soft and hard tissue destruction that results from periodontitis. Localized delivery of growth factors to the periodontium is an emerging and versatile therapeutic approach, with the potential to become a powerful tool in future regenerative periodontal therapy. Optimized delivery regimes and well-defined release kinetics appear to be logical prerequisites for safe and efficacious clinical application of growth factors and to avoid unwanted side effects and toxicity. While adequate concentrations of growth factor(s) need to be appropriately localized, delivery vehicles are also expected to possess properties such as protein protection, precision in controlled release, biocompatibility and biodegradability, self-regulated therapeutic activity, potential for multiple delivery, and good cell/tissue penetration. Here, current knowledge, recent advances, and future possibilities of growth factor delivery strategies are outlined for periodontal regeneration. First, the role of those growth factors that have been implicated in the periodontal healing/regeneration process, general requirements for their delivery, and the different material types available are described. A detailed discussion follows of current strategies for the selection of devices for localized growth factor delivery, with particular emphasis placed upon their advantages and disadvantages and future prospects for ongoing studies in reconstructing the tooth supporting apparatus. © 2009 Wiley Periodicals, Inc. Med Res Rev, 29, No. 3, 472-513, 2009 [source] Identification of novel markers expressed during fin regeneration by microarray analysis in medaka fishDEVELOPMENTAL DYNAMICS, Issue 9 2007Masanobu Nishidate Abstract Urodeles and fish have a remarkable ability to regenerate lost body parts, whereas many higher vertebrates, including mammals, retain only a limited capacity. It is known that the formation of specialized cell populations such as the wound epidermis or blastema is crucial for regeneration; however, the molecular basis for their formation has not been elucidated. Recently, approaches using differential display and microarray have been done in zebrafish for searching molecules involved in regeneration. Here, we used the medaka fish, a distantly diverged fish species, for microarray screening of transcripts up-regulated during regeneration. By setting criteria for selecting transcripts that are reliably and reproducibly up-regulated during regeneration, we identified 140 transcripts. Of them, localized in situ expression of 12 transcripts of 22 tested was detected either in differentiating cartilage, basal wound epidermis, or blastema. Our results provide useful molecular markers for dissecting the regeneration process at a fine cellular resolution. Developmental Dynamics 236:2685,2693, 2007. © 2007 Wiley-Liss, Inc. [source] Retroviral labeling of Schwann cells: In vitro characterization and in vivo transplantation to improve peripheral nerve regenerationGLIA, Issue 1 2001Afshin Mosahebi Abstract Transplantation of Schwann cells (SCs) is a promising treatment modality to improve neuronal regeneration. Identification of the transplanted cells is an important step when studying the development of this method. Genetic labeling is the most stable and reliable method of cell identification, but it is still unclear whether it has deleterious effect on SC characteristics. Our aim was to achieve a stable population of SCs transduced with the lacZ gene at a high frequency using a retroviral vector in vitro, and to follow the labeled SC in vitro to assess their viability and phenotypic marker expression. Furthermore, we transplanted lacZ -labeled SCs in a conduit to repair peripheral nerve to investigate their effect on nerve regeneration in vivo. Rat and human SCs were cultured and transduced with an MFG lacZ nls marker gene, achieving a transduction rate of 80% and 70%, respectively. Rat SCs were kept in culture for 27 weeks and examined every 4 weeks for expression of lacZ, viability, and phenotypic marker expression of GFAP, p75, MHC I and II. Throughout this period, transduced rat SCs remained viable and continued to proliferate. The proportion of cells expressing lacZ dropped only by 10% and the expression of phenotypic markers remained stable. Transduced human SCs were followed up for 4 weeks in culture. They proliferated and continued to express the lacZ gene and phenotypic marker expression of GFAP and p75 was preserved. Primary culture of transduced rat SCs were transplanted, syngeneically, in a conduit to bridge a 10 mm gap in sciatic nerve and the grafts were examined after 3 weeks for the presence and participation of labeled SCs and for axonal regeneration distance. Transplanted transduced rat SCs were clearly identified, taking part in the regeneration process and enhancing the axonal regeneration rate by 100% (at the optimal concentration) compared to conduits without SCs. Thus, retroviral introduction of lacZ gene has no deleterious effect on SCs in vitro and these SCs take part and enhance nerve regeneration in vivo. GLIA 34:8,17, 2001. © 2001 Wiley-Liss, Inc. [source] Cellular responses in experimental liver injury: Possible cellular origins of regenerative stem-like progenitor cells,HEPATOLOGY, Issue 5 2005William B. Coleman Ph.D. Background/Aims Mature hepatocytes divide to restore liver mass after injury. However, when hepatocyte division is impaired by retrorsine poisoning, regeneration proceeds from another cell type: the small hepatocyte-like progenitor cells (SHPCs). Our aim was to test whether SHPCs could originate from mature hepatocytes. Methods Mature hepatocytes were genetically labeled using retroviral vectors harboring the ,-galactosidase gene. After labeling, retrorsine was administered to rats followed by partial hepatectomy to trigger regeneration. A liver biopsy was performed one month after surgery and rats were sacrificed one month later. Results We observed the proliferation of small hepatocytes arranged in clusters in liver biopsies. These cells expressed Ki67 antigen and displayed high mitotic index. At sacrifice, regeneration was completed and clusters had merged. A significant proportion of clusters also expressed ,-galactosidase demonstrating their origin from labeled mature hepatocytes. Finally, the overall proportion of ,-galactosidase positive cells was identical at the time of hepatectomy as well as in liver biopsy and at sacrifice. Conclusions The constant proportion of ,-galactosidase positive cells during the regeneration process demonstrates that mature hepatocytes are randomly recruited to proliferate and compensate parenchyma loss in this model. Furthermore, mature hepatocytes are the source of SHPC after retrorsine injury. [source] Tissue Engineering Strategies Designed to Realize the Endogenous Regenerative Potential of Peripheral NervesADVANCED MATERIALS, Issue 46 2009Vivek Mukhatyar Abstract http://doi.wiley.com/10.1002/adma.v21:32/33 Bridging peripheral nerve gaps without the use of autografts has significant clinical importance. But in order to rationally design novel scaffolds, a good understanding of the nerve regeneration process is vital. Appropriate amount of structural and chemical cues are required to stimulate the endogenous mechanisms of repair and functional recovery. Synthetic and natural materials present various opportunities to induce the growth of supporting cells as well as promote axon regeneration. An overview of tissue engineering strategies currently being explored that stimulate the different steps of the regenerative sequence is presented. [source] Attenuated apoptosis response to Fas-ligand in active ulcerative colitisINFLAMMATORY BOWEL DISEASES, Issue 12 2008Jakob B. Seidelin MD Abstract Background: From mainly carcinoma cell line studies, apoptosis has been thought to play a major role in the pathogenesis of ulcerative colitis (UC). Apoptosis has been suggested to be due to a Fas ligand / Fas receptor interaction, but has never been studied in cells from patients with active UC. The aim was to investigate both the spontaneous and the cell death receptor ligand-induced apoptosis in UC. Methods: Twenty patients with UC and 16 control subjects who underwent routine colonoscopy either for the control or surveillance of their disease or where the diagnosis of irritable bowel syndrome was subsequently reached were included. Cultures of isolated colonic crypts were obtained from biopsies and cultured for 4 to 16 hours with Fas ligand or Fas ligand and costimulation with interferon-, (IFN-,). Control experiments were performed on HT29 cells. Apoptosis was assessed by independent methods. Results: Isolated colonocytes from healthy subjects or patients with remission in UC had a dose-dependent response to Fas ligand. This response was abolished in patients with active UC (P < 0.002), and costimulation with IFN-, did not alter this response. Patients with active UC had an increased apoptosis rate of 9.5% compared with controls (P < 0.05). Conclusions: The current study indicates that colonocytes do not respond to cytokine exposure and inflammation by an increased vulnerability, as previously thought. Colonocytes seem to activate cytoprotective programs in response to inflammation. Apart from supporting the regeneration process during inflammation, this response could additionally cause an increased susceptibility to neoplastic transformation. (Inflamm Bowel Dis 2008) [source] Effect of internal cooling/heating coil on adsorption/regeneration of solid desiccant tray for controlling air humidityINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2008B. N. Hung Abstract Thermal performances of solid desiccant tray having internal cooling/heating coil for air humidity adsorption and desiccant regeneration are investigated. Three units of desiccant tray each of 48,cm,×,48,cm cross-sectional area and 2.5,cm thickness filled with silica gel are tested in a wind tunnel. For adsorption process, an air stream is flowing through the desiccant trays and the air humidity is captured by the silica gel. Approximately 10,40% of air humidity could be adsorbed more in case of the internal cooling. Besides, the outlet air temperature increases only slightly. In regeneration process, a hot air stream is used to repel the moisture in the silica gel. With the internal heating, the regeneration time is shorter compared with that without internal water heating. In addition, a correlation for calculating the adsorption/regeneration performance of the silica gel trays is developed and the results from the model agree well with the experimental data. Copyright © 2008 John Wiley & Sons, Ltd. [source] GeneChip® analysis after acute spinal cord injury in ratJOURNAL OF NEUROCHEMISTRY, Issue 4 2001Guoqing Song Spinal cord injury (SCI) leads to induction and/or suppression of several genes, the interplay of which governs the neuronal death and subsequent loss of motor function. Using GeneChip®, the present study analyzed changes in the mRNA abundance at 3 and 24 h after SCI in adult rats. SCI was induced at T9 level by the New York University impactor by dropping a 10-g weight from a height of 25 mm. Several transcription factors, immediate early genes, heat-shock proteins, pro-inflammatory genes were up-regulated by 3 h, and persisted at 24 h, after SCI. On the other hand, some neurotransmitter receptors and transporters, ion channels, kinases and structural proteins were down-regulated by 3 h, and persisted at 24 h, after SCI. Several genes that play a role in growth/differentiation, survival and neuroprotection were up-regulated at 24 h after SCI. Using real-time quantitative PCR, the changes observed by GeneChip® were confirmed for seven up-regulated (interleukin-6, heat-shock protein-70, heme oxygenase-1, suppressor of cytokine signaling 2, suppressor of cytokine signaling 3, interferon regulatory factor-1, neuropeptide Y), two down-regulated (vesicular GABA transporter and cholecystokinin precursor) and two unchanged (Cu/Zn-superoxide dismutase and phosphatidyl inositol-3-kinase) genes. The present study shows that inflammation, neurotransmitter dysfunction, increased transcription, ionic imbalance and cytoskeletal damage starts as early as 3 h after SCI. In addition to these effects, 24 h after SCI the repair and regeneration process begins in an attempt to stabilize the injured spinal cord. [source] Hyperbaric oxygen treatment has different effects on nerve regeneration in acellular nerve and muscle graftsJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2001Yasumasa Nishiura Abstract Effects of hyperbaric oxygen treatment (HBO) on nerve regeneration in acellular nerve and muscle grafts were investigated in rats. Nerve and muscle grafts were made acellular by freeze-thawing and the obtained grafts were used to bridge a 10-mm gap in the sciatic nerve on the left and right sides, respectively. Rats were treated with HBO (100% oxygen for 90 minutes at 2.5 atmospheres absolute pressure ATA) twice a day for 7 days. Axonal outgrowth, Schwann cell migration and invasion of macrophages were examined 10 days after the graft procedure by staining neurofilaments, S-100 proteins and the macrophage antibodies ED1 and ED2, respectively. Axonal outgrowth and Schwann cell migration in acellular nerve grafts were superior to that found in the acellular muscle grafts. However, there was no difference between HBO-treated and non-treated rats in acellular nerve grafts. Such a difference was found in acellular muscle grafts concerning both axonal outgrowth and Schwann cell migration from the proximal nerve end. No differences in the content of macrophages or neovascularization (alkaline phosphatase staining) in either of the grafts and treatments were seen. It is concluded that there is a differential effect of HBO-treatment in acellular nerve and muscle grafts and that HBO-treatment has no effect on the regeneration process in acellular nerve grafts, in contrast to fresh cellular nerve grafts where a beneficial effect has previously been reported. [source] Quantitative liver function tests in donors and recipients of living donor liver transplantationLIVER TRANSPLANTATION, Issue 4 2006Christoph Jochum The unique ability of the liver to regenerate quickly after resection makes living donor liver transplantation (LDLT) possible. This technique uses the unique ability of the liver to regenerate to full size after partial resection. However, the quality and course of this regeneration process in humans are still widely unexplored. In the present study we investigated the quantitative liver function tests galactose elimination capacity (GEC), indocyanine green half-life (ICG), and lidocaine half-life as markers for the quality of the liver regeneration in the first 3 months after LDLT. In this study, 22 consecutive living liver donors and their corresponding recipients were analyzed at baseline and at 10 and 90 days after LDLT. Six recipients lost their grafts during the study period. We compared donors and recipients at the different time points. After LDLT, GEC decreased (,42.6%) and ICG increased (+50.6%) significantly in donors. ICG and GEC remained significantly altered over 3 months in donors with an improvement between days 10 and 90 (GEC, +59.3%; ICG, ,9.1%). ICG and GEC improved significantly in recipients between days 10 and 90 (ICG, ,63.7%; GEC, +16.3%). The lidocaine half-life showed no significant changes. The donors had better test results and recovered faster than the recipients. In conclusion, after LDLT the parameters for liver capacity and flow remain altered in donors and recipients despite rapid volume growth. Liver Transpl 12:544,549, 2006. © 2006 AASLD. [source] Photoactive Protochlorophyllide Regeneration in Cotyledons and Leaves from Higher Plants,,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2000Benoīt Schoefs ABSTRACT Chlorophyll accumulation during greening implies the continuous transformation of photoactive protochlorophyllide (Pchlide) to chlorophyllide. Since this reaction is a light-dependent step, the study of regeneration of photoactive Pchlide under a continuous illumination is difficult. Therefore this process is best studied on etiolated plants during a period of darkness following the initial photoreduction of photoactive Pchlide. In this study, the regeneration process has been studied using spinach cotyledons, as well as barley and bean leaves, illuminated by a single saturating flash. The regeneration was characterized using 77 K fluorescence emission and excitation spectra and high-performance liquid chromatography. The fluorescence data indicated that the same spectral forms of photoactive Pchlide are regenerated by different pathways: (1) photoactive Pchlide regeneration starts immediately after the photoreduction through the formation of a nonphotoactive Pchlide form, emitting fluorescence at approximately 651 nm. This form is similar to the large aggregate of photoactive Pchlide present before the illumination, but it contains oxidized form of nicotinamide adenine dinucleotide phosphate, instead of the reduced form (NADPH), in the ternary complexes; and (2) after the dislocation of the large aggregates of chlorophyllide,light-dependent NADPH:Pchlide a photooxidoreductase,NADPH ternary complexes, the regeneration occurs at the expense of the several nonphotoactive Pchlide spectral forms present before the illumination. [source] Comparative proteomic analysis of mesenchymal stem cells derived from human bone marrow, umbilical cord, and placenta: Implication in the migrationPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 1 2009Guo Li Abstract Umbilical cord (UC) and placenta (P) have been suggested as alternatives to bone marrow (BM) as sources of mesenchymal stem cells (MSC) for cell therapy, with both UC- and P-MSC possess immunophenotypic and functional characteristics similar to BM-MSC. However, their migration capacity, which is indispensable during tissue regeneration process, is unclear. Under defined conditions, the migration capacity of BM- and P-MSC was found 5.9- and 3.2-folds higher than that of UC-MSC, respectively. By the use of 2-DE and combined MS and MS/MS analysis, six differentially expressed proteins were identified among these MSC samples, with five of them known to be involved in cell migration as migration enhancing or inhibiting proteins. Consistent with their migration capacity, the levels of migration enhancing proteins including cathepsin B, cathepsin D and prohibitin,were significantly lower in UC-MSC when compared with those in BM- and P-MSC. For the migration inhibiting proteins such as plasminogen activator inhibitor-1 (PAI-1) and manganese superoxide dismutase, higher expression was found in the UC-MSC. We also showed that the overexpression of the PAI-1 impaired the migration capacity of BM- and P-MSC while silencing of PAI-1 enhanced the migration capacity of UC-MSC. Our study indicates that PAI-1 and other migration-related proteins are pivotal in governing the migration capacity of MSC. [source] Heparanase expression during normal liver development and following partial hepatectomyTHE JOURNAL OF PATHOLOGY, Issue 1 2004Orit Goldshmidt Abstract Heparan sulphate proteoglycans are major components of the liver extracellular matrix. Their cleavage by heparanase (endo-,-glucuronidase) may thus be involved in liver-specific normal and pathological processes. Heparanase mRNA and protein were expressed during liver development but not in the mature healthy liver. A biphasic gain of heparanase expression, detected by immunostaining, western blotting, and real-time RT-PCR, was clearly noted following partial hepatectomy, peaking at 12 and 96,168 h and subsiding 2 weeks post-surgery. Expression of heparan sulphate gradually increased throughout the regeneration process. Unlike heparanase, baseline levels of matrix metalloproteinase-2 (MMP-2) were detected in the intact liver, increasing up to 4 days following partial hepatectomy and subsiding at day 10. Bands matching MMP-9 were absent prior to hepatectomy, but visible 2 h post-hepatectomy. Thioacetamide-induced liver fibrosis was associated with increased levels of MMP-9 and MMP-2, correlating with the severity of the disease. Elevated heparanase levels were noted in the early stages of fibrosis, with no further increase evident in rats exhibiting higher fibrotic grades. Taken together, these data suggest a role for heparanase during liver development and remodelling. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Efficient transposition of the Tnt1 tobacco retrotransposon in the model legume Medicago truncatulaTHE PLANT JOURNAL, Issue 1 2003Isabelle D'Erfurth Summary The tobacco element, Tnt1, is one of the few active retrotransposons in plants. Its transposition is activated during protoplast culture in tobacco and tissue culture in the heterologous host Arabidopsis thaliana. Here, we report its transposition in the R108 line of Medicago truncatula during the early steps of the in vitro transformation,regeneration process. Two hundred and twenty-five primary transformants containing Tnt1 were obtained. Among them, 11.2% contained only transposed copies of the element, indicating that Tnt1 transposed very early and efficiently during the in vitro transformation process, possibly even before the T-DNA integration. The average number of insertions per transgenic line was estimated to be about 15. These insertions were stable in the progeny and could be separated by segregation. Inspection of the sequences flanking the insertion sites revealed that Tnt1 had no insertion site specificity and often inserted in genes (one out of three insertions). Thus, our work demonstrates the functioning of an efficient transposable element in leguminous plants. These results indicate that Tnt1 can be used as a powerful tool for insertion mutagenesis in M. truncatula. [source] Progenitor cells in liver regeneration: molecular responses controlling their activation and expansion,APMIS, Issue 11-12 2005ERIC SANTONI-RUGIU Although normally quiescent, the adult mammalian liver possesses a great capacity to regenerate after different types of injuries in order to restore the lost liver mass and ensure maintenance of the multiple liver functions. Major players in the regeneration process are mature residual cells, including hepatocytes, cholangiocytes and stromal cells. However, if the regenerative capacity of mature cells is impaired by liver-damaging agents, hepatic progenitor cells are activated and expand into the liver parenchyma. Upon transit amplification, the progenitor cells may generate new hepatocytes and biliary cells to restore liver homeostasis. In recent years, hepatic progenitor cells have been the subject of increasing interest due to their therapeutic potential in numerous liver diseases as alternative or supportive/complementary tools to liver transplantation. While the first investigations on hepatic progenitor cells have focused on their origin and phenotypic characterization, recent attention has focused on the influence of the hepatic microenvironment on their activation and proliferation. This microenvironment comprises the extracellular matrix, epithelial and non-epithelial resident liver cells, and recruited inflammatory cells as well as the variety of growth-modulating molecules produced and/or harboured by these elements. The cellular and molecular responses to different regenerative stimuli seem to depend on the injury inflicted and consequently on the molecular microenvironment created in the liver by a certain insult. This review will focus on molecular responses controlling activation and expansion of the hepatic progenitor cell niche, emphasizing similarities and differences in the microenvironments orchestrating regeneration by recruitment of progenitor cell populations or by replication of mature cells. [source] Application of supercritical fluid extraction to regenerate spent Pd-active carbon catalystENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 4 2007Lidia D Abstract Pd-active carbon-type catalysts are used in a wide variety of processes, typical examples of which are liquid-phase hydrogenation reactions. In the case of these catalysts, a loss of their catalytic activity is observed. The aim of the present work was to assess the possibility of regenerating spent Pd/AC catalysts using supercritical fluid extraction. The following Pd/AC catalyst samples were investigated and compared: a commercial 10 wt % Pd catalyst (Aldrich) (denoted by CC), a spent catalyst (SC), SC subjected to supercritical fluid,CO2 extraction (SC/SFE/C), SC subjected to supercritical fluid,CO2,ethanol extraction (SC/SFE/C-Et), and SC subjected to supercritical fluid,ethane,propane extraction (SC/SFE/E-P). The last three catalysts were additionally subjected to heating in a hydrogen atmosphere at 410 K for 3 h. These were denoted by SC/SFE/C/H, SC/SFE/C-Et/H, and SC/SFE/E-P/H, respectively. The spent Pd/AC catalyst (SC) consists of mixed CC samples used in the reduction with hydrogen of various organic compounds. The catalysts CC, SC/SFE/C, SC/SFE/C/H, SC/SFE/C-Et/H, and SC/SFE/E-P/H were tested in the reduction of octanoylbenzene with hydrogen. The activity of the catalysts was estimated by measuring the reaction time and also the amount of hydrogen used in relation to the theoretical quantity required for the reaction. XPS and XRD methods were used to evaluate the changes occurring in the form of the palladium present on the Pd/AC catalyst surface during the regeneration processes. It was found that supercritical fluid-CO2 extraction followed by heating in a hydrogen atmosphere is the most effective method for regenerating that catalyst. The results of our investigations indicate that regeneration of a spent Pd/AC catalyst, irrespective of the reaction in which it has been used, should be based on the complete removal of byproducts, the purification of the catalyst surface, and the restoration of the original form of the palladium. The procedure proposed in this paper, i.e. SFE (CO2) and heating in H2, fulfils both the conditions mentioned above. © 2007 American Institute of Chemical Engineers Environ Prog, 2007 [source] LRRN6A/LERN1 (leucine-rich repeat neuronal protein 1), a novel gene with enriched expression in limbic system and neocortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2003Laura Carim-Todd Abstract Human chromosome 15q24-q26 is a very complex genomic region containing several blocks of segmental duplications to which susceptibility to anxiety disorders has been mapped (Gratacos et al., 2001, Cell, 106, 367,379; Pujana et al., 2001, Genome Res., 11, 98,111). Through an in silico gene content analysis of the 15q24-q26 region we have identifie1d a novel gene, LRRN6A (leucine-rich repeat neuronal 6A), and confirmed its location to the centromeric end of this complex region. LRRN6A encodes a transmembrane leucine-rich repeat protein, LERN1 (leucine-rich repeat neuronal protein 1), with similarity to proteins involved in axonal guidance and migration, nervous system development and regeneration processes. The identification of homologous genes to LRRN6A on chromosomes 9 and 19 and the orthologous genes in the mouse genome and other organisms suggests that LERN proteins constitute a novel subfamily of LRR (leucine-rich repeat)-containing proteins. The LRRN6A expression pattern is specific to the central nervous system, highly and broadly expressed during early stages of development and gradually restricted to forebrain structures as development proceeds. Expression level in adulthood is lower in general but remains stable and significantly enriched in the limbic system and cerebral cortex. Taken together, the confirmation of LRRN6A's expression profile, its predicted protein structure and its similarity to nervous system-expressed LRR proteins with essential roles in nervous system development and maintenance suggest that LRRN6A is a novel gene of relevance in the molecular and cellular neurobiology of vertebrates. [source] Potential of deoxynivalenol to induce transcription factors in human hepatoma cellsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 4 2009Carina Nielsen Abstract To assess the hepatotoxicity of deoxynivalenol (DON), human hepatoma cells (Hep-G2) were used as an in vitro model. After exposing Hep-G2 cells to low (1 ,M) and high dose (10 ,M), gene expression profiles were analysed by microarray. More than 5% of genes were up-regulated, most of them being involved in transcriptional regulation. By real-time RT-PCR, elevated expression of transcription factors, commonly induced by activation of MAPK-pathway, was demonstrated for Hep-G2 cells on mRNA and protein level. Further studies, involving U937 human monocytes, showed that effects of DON treatment on mRNA and protein level were concentration-dependent and cell-specific. An inverse relation was noticed for the level of DON induced expression of transcription factors (JUN, FOS, EGR1 and ATF3) and the susceptibility of the cell lines towards the mycotoxin. This is the first report giving evidence that on a molecular level the mild hepatotoxic effects of DON are probably caused by the induction of transcription factors which are known to be associated with injury-induced liver regeneration processes. With ATF3, a novel downstream target gene was identified in DON-related cell signalling suggesting a potential linkage between molecular action and biological effects like reduction of glycogen storage in liver tissue. [source] R2: Identification of renal potential progenitor/stem cells that participate in the renal regeneration processes of kidney allograft fibrosisNEPHROLOGY, Issue 6 2008JI BAO SUMMARY: Aim: Many strategies are explored to ameliorate kidney allograft tubular atrophy and interstitial fibrosis (TA/IF), but little progress has been achieved. The latest evidence suggested that CD133+ cell in kidney represent a potential multipotent adult resident stem cell population that may contribute to the renal injury repair. Here we investigate whether the CD133+ cells exist in transplanted renal and exert a growth and self-repair procedure in TA/IF. Methods: Allografts from rat kidney transplant models were harvested at 4 weeks, 8 weeks and 12 weeks post transplantation. We performed immunohistochemistry to detect the CD133+ cells and immunofluorescence to detect the co-expression of CD133 or Pax-2 with Ki-67. We furthermore analysed the E-cadherin using serial sections. Results: CD133+ cells were seldom seen in control kidney, but distributed sporadically in the cortex parenchyma along with the deterioration of TA/IF. The number of CD133+ cell increased after 4 weeks and reached the peak at 8 weeks, then decreased at 12 weeks. From 8 weeks, some new tubules expressing E-cadherin were constructed with CD133+ cells. Almost all the CD133+ cells were Ki-67-positive, but not all the Ki-67+ cells expressed CD133. The rest Ki-67+ cells almost expressed Pax-2. Conclusion: Our study reveals that when majority of the tubules are damaged, a self-repair mechanism is evoked by potential adult stem cells to compensate the renal function. Thus, potential adult resident stem cells offer a new avenue for autologous cell therapies in TA/IF. [source] Relative enhancement of photosynthesis and growth at elevated CO2 is greater under sunflecks than uniform irradiance in a tropical rain forest tree seedlingPLANT CELL & ENVIRONMENT, Issue 12 2002A. D. B. LEAKEY Abstract The survivorship of dipterocarp seedlings in the deeply shaded understorey of South-east Asian rain forests is limited by their ability to maintain a positive carbon balance. Photosynthesis during sunflecks is an important component of carbon gain. To investigate the effect of elevated CO2 upon photosynthesis and growth under sunflecks, seedlings of Shorealeprosula were grown in controlled environment conditions at ambient or elevated CO2. Equal total daily photon flux density (PFD) (,7·7 mol m,2 d,1) was supplied as either uniform irradiance (,170 µmol m,2 s,1) or shade/fleck sequences (,30 µmol m,2 s,1/,525 µmol m,2 s,1). Photosynthesis and growth were enhanced by elevated CO2 treatments but lower under flecked irradiance treatments. Acclimation of photosynthetic capacity occurred in response to elevated CO2 but not flecked irradiance. Importantly, the relative enhancement effects of elevated CO2 were greater under sunflecks (growth 60%, carbon gain 89%) compared with uniform irradiance (growth 25%, carbon gain 59%). This was driven by two factors: (1) greater efficiency of dynamic photosynthesis (photosynthetic induction gain and loss, post-irradiance gas exchange); and (2) photosynthetic enhancement being greatest at very low PFD. This allowed improved carbon gain during both clusters of lightflecks (73%) and intervening periods of deep shade (99%). The relatively greater enhancement of growth and photosynthesis at elevated CO2 under sunflecks has important potential consequences for seedling regeneration processes and hence forest structure and composition. [source] Chimpanzee seed dispersal quantity in a tropical montane forest of RwandaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 11 2009Nicole D. Gross-Camp Abstract We describe chimpanzee seed dispersal in the tropical montane forest of Nyungwe National Park (NNP), Rwanda, for a total of three years from January 1998 through May 2000 and May 2006 through March 2007. Relatively few studies have examined chimpanzee seed dispersal in montane communities where there are generally fewer fruiting tree species than in lowland forests. Such studies may reveal new insights into chimpanzee seed dispersal behaviors and the role that they play in forest regeneration processes. Chimpanzees are large-bodied, highly frugivorous, and tend to deposit the seeds of both large- and small-seeded fruits they consume in a viable state. We found that chimpanzees dispersed a total of 37 fruiting species (20 families) in their feces, 35% of which were large-seeded trees (,0.5,cm). A single large-seeded tree, Syzygium guineense, was the only species to be dispersed in both wadges and feces. Based on phenological patterns of the top five large-seeded tree species found in chimpanzee feces, our results indicate that chimpanzees do not choose fruits based on their availability. There was, however, a positive relationship between the presence of Ekebergia capensis seeds in chimpanzee feces and S. guineense seeds in chimpanzee wadges and their respective fruit availabilities. Our data reveal that proportionately fewer chimpanzee fecal samples at NNP contained seeds than that reported in two other communities in the Albertine Rift including one at mid-elevation and one in montane forest. As in other chimpanzee communities, seeds of Ficus spp. were the most common genus in NNP chimpanzee feces. Our data do not support previous studies that describe Ficus spp. as a fallback food for chimpanzees and highlights an intriguing relationship between chimpanzees and the large-seeded tree species, S. guineense. Am. J. Primatol. 71:901,911, 2009. © 2009 Wiley-Liss, Inc. [source] Histological Studies of Growing and Mature Antlers of Red Deer Stags (Cervus elaphus)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2009M. Cegielski Summary This study aims at presenting histology of growing and mature antlers in red deer stag (Cervus elaphus). Growing antlers constitute a model organ for examining regeneration processes of tissues because they are the only mammalian appendages capable of regeneration. Histological study revealed that the tip of a growing antler consists of hairy skin, perichondrium, mesenchyme and chondroprogenitors area. By performing immunochistochemistry, we found that cell expressing Ki-67 and PCNA antigens were localized in basal layer of epidermis, skin glands and beneath their secretory sections, mesenchyme as well as within and in the vicinity of central blood vessels. Ultrastructurally, cells from chondroprogenitors zone have chondroblast-like morphology and take part in producing of collagen fibres followed by the process of cartilage mineralization. However, mature antlers also consist of lamellar osseous tissue. [source] | |||||||||||||||||||||||||||||||