Excessive Accumulation (excessive + accumulation)

Distribution by Scientific Domains

Selected Abstracts

Restriction of dietary calories, fat and iron improves non-alcoholic fatty liver disease

Mika Yamamoto
Abstract Background:, The pathogenesis of non-alcoholic steatohepatitis (NASH) is unclear. Recent studies suggested that oxidative stress plays an important role in the mechanism of NASH. Excessive accumulation of iron in the liver causes oxidative stress. The aim of the present study was to evaluate the grade of hepatic iron accumulation and the therapeutic response to restriction of calories, fat and iron in patients with non-alcoholic fatty liver disease (NAFLD). Methods:, Twenty-seven NAFLD patients were enrolled. The patients were categorized into two groups: 17 patients with NASH and 10 with simple steatosis. Twelve NAFLD patients (NASH, n = 9; simple steatosis, n = 3) were given a dietary prescription including restriction of energy, fat and iron. Results:, Positive iron staining was observed in 71% and 50% of patients with NASH and simple steatosis, respectively. The average energy intake, fat energy fraction and iron intake decreased significantly 6 months after the beginning of the diet in all patients. In addition, the levels of serum transaminase and ferritin were significantly decreased. Conclusion:, Dietary restriction of calories, fat and iron improved NAFLD. Reduced serum ferritin levels appear to reduce oxidative stress in the liver. [source]

Antimelanogenesis effect of Tunisian herb Thymelaea hirsuta extract on B16 murine melanoma cells

Mitsuko Kawano
Abstract:, Skin pigmentation is the result of melanogenesis that occurs in melanocytes and/or melanoma cells. Although melanogenesis is necessary for the prevention of DNA damage and cancer caused by UV irradiation, excessive accumulation of melanin can also cause melanoma. Thus, we focused on the antimelanogenesis effect of an extract from Thymelaea hirsuta, a Tunisian herb. Murine melanoma B16 cells were treated with T. hirsuta extract, and then cell viability and synthesized melanin content were measured. We found that the T. hirsuta extract decreased the synthesized melanin content in B16 cells without cytotoxicity. Tyrosinase is a key enzyme of melanogenesis and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation is known to be related to melanogenesis inhibition. To clarify its mechanism, we also determined ERK1/2 phosphorylation and tyrosinase expression level. ERK1/2 was immediately phosphorylated in cells just after treatment with the extract. The tyrosinase expression was inhibited after 24 h of stimulation with the extract. The T. hirsuta extract was fractionated, and we found that one fraction considerably decreased the melanin synthesis in B16 cells and that this fraction contains daphnanes as the main component. This indicates that our findings might be attributable to daphnanes. [source]

Spindle pole fragmentation due to proteasome inhibition

Anka G. Ehrhardt
During interphase, the centrosome concentrates cell stress response molecules, including chaperones and proteasomes, into a proteolytic center. However, whether the centrosome functions as proteolytic center during mitosis is not known. In this study, cultured mammalian cells were treated with the proteasome inhibitor MG 132 and spindle morphology in mitotic cells was characterized in order to address this issue. Proteasome inhibition during mitosis leads to the formation of additional asters that cause the assembly of multipolar spindles. The cause of this phenomenon was investigated by inhibiting microtubule-based transport and protein synthesis. These experimental conditions prevented the formation of supernumerary asters during mitosis. In addition, the expression of dsRed without proteasome inhibition led to the fragmentation of spindle poles. These experiments showed that the formation of extra asters depends on intact microtubule-based transport and protein synthesis. These results suggest that formation of supernumerary asters is due to excessive accumulation of proteins at the spindle poles and consequently fragmentation of the centrosome. Together, this leads to the conclusion that the centrosome functions as proteolytic center during mitosis and proteolytic activity at the spindle poles is necessary for maintaining spindle pole integrity. © 2005 Wiley-Liss, Inc. [source]

Mechanisms of Cardiac Fibrosis in Hypertension

Javier Díez MD
Changes in the composition of cardiac tissue develop in hypertensive patients with left ventricular hypertrophy (ie, hypertensive heart disease) and lead to structural remodeling of the myocardium. One of these changes is related to the disruption of the equilibrium between the synthesis and degradation of collagen types I and III molecules, which results in an excessive accumulation of collagen types I and III fibers within the myocardium. Myocardial fibrosis is the consequence of a number of pathologic processes mediated by mechanical, neurohormonal, and cytokine routes. The clinical relevance of fibrosis is that it may contribute to heart failure and other cardiac complications in patients with hypertensive heart disease. This brief review focuses on the mechanisms of hypertensive myocardial fibrosis. [source]

Quantitative Lipid Metabolomic Changes in Alcoholic Micropigs With Fatty Liver Disease

ALCOHOLISM, Issue 4 2009
Angela M. Zivkovic
Background:, Chronic ethanol consumption coupled with folate deficiency leads to rapid liver fat accumulation and progression to alcoholic steatohepatitis (ASH). However, the specific effects of alcohol on key liver lipid metabolic pathways involved in fat accumulation are unknown. It is unclear whether lipid synthesis, lipid export, or a combination of both is contributing to hepatic steatosis in ASH. Methods:, In this study we estimated the flux of fatty acids (FA) through the stearoyl-CoA desaturase (SCD), phosphatidylethanolamine- N -methyltransferase (PEMT), and FA elongation pathways in relation to liver triacylglycerol (TG) content in Yucatan micropigs fed a 40% ethanol folate-deficient diet with or without supplementation with S -adenosyl methionine (SAM) compared with controls. Flux through the SCD and PEMT pathways was used to assess the contribution of lipid synthesis and lipid export respectively on the accumulation of fat in the liver. Liver FA composition within TG, cholesterol ester (CE), phosphatidylethanolamine, and phosphatidylcholine classes was quantified by gas chromatography. Results:, Alcoholic pigs had increased liver TG content relative to controls, accompanied by increased flux through the SCD pathway as indicated by increases in the ratios of 16:1n7 to 16:0 and 18:1n9 to 18:0. Conversely, flux through the elongation and PEMT pathways was suppressed by alcohol, as indicated by multiple metabolite ratios. SAM supplementation attenuated the TG accumulation associated with alcohol. Conclusions:, These data provide an in vivo examination of liver lipid metabolic pathways confirming that both increased de novo lipogenesis (e.g., lipid synthesis) and altered phospholipid metabolism (e.g., lipid export) contribute to the excessive accumulation of lipids in liver affected by ASH. [source]

Spatial variation of intestinal skatole production and microbial community in Jinhua and Landrace pigs,

Cai-Yan Li
Abstract BACKGROUND: An excessive accumulation of skatole in pigs is a major contributor to boar taint. Intestinal skatole concentrations may vary among different pig segments and breeds. The objective of this study was to evaluate the spatial variation of intestinal skatole production and the microbial community in local Jinhua and exotic Landrace pigs. RESULTS: For both breeds, skatole concentration increased towards the rectum and segment had a significant effect on skatole (P < 0.001). The caecal skatole concentration in Landrace was significantly lower than proximal, distal colonic and rectal skatole levels (P < 0.05). Compared with Jinhua pigs, the rectal skatole and proximal and distal colonic indole levels were significantly higher in Landrace pigs (P < 0.05). Volatile fatty acids were significantly affected by breed except for isobutyrate and isovalerate (P < 0.05), with higher butyrate level and lower pH in Landrace pigs (P < 0.05). There were no significant differences in mitosis and apoptosis for the two breeds. The denaturing gradient gel electrophoresis profile showed differences between breeds and segments within one breed, though some bands were common to all samples. CONCLUSION: The higher skatole levels in Landrace pigs may be not associated with higher intestinal apoptosis. The results suggested that pig genotype plays a role in the establishment of the host-specific microbiota and that the variations in fermentation patterns are more likely to explain differences in intestinal skatole production. Copyright © 2009 Society of Chemical Industry [source]

Proteomic analysis of sera of asymptomatic, early-stage patients with Wilson's disease

Jung-Young Park
Abstract Wilson's disease (WD) is characterized by excessive accumulation of intracellular copper in liver and extrahepatic tissues, leading to significant oxidative stress and tissue damage. To date, several diagnostic biomarkers for WD such as serum ceruloplasmin, serum or urine copper levels and copper content in liver have been identified. However, these biomarkers may not be convincing for the diagnosis in some WD patients. To identify additional novel diagnostic biomarkers, we compared the serum protein profiles of asymptomatic childhood WD patients (n=20), without neurologic manifestation or liver cirrhosis, with normal controls (n=13). Fourteen spots, five up-regulated and nine down-regulated (>2-fold), were differentially expressed in WD patients in comparison to normal control on 2-DE. Among them, three spots were down-regulated in both male and female WD. MS/MS analysis revealed that the three spots were complement component C3, complement factor B and alpha-2 macroglobulin. By comparative proteome analysis, complement component C3, complement factor B and alpha-2 macroglobulin, which are related to oxidative stress and inflammation, turned out to be good candidates for novel diagnostic biomarkers for early stages of WD. [source]

Fox-2 protein regulates the alternative splicing of scleroderma-associated lysyl hydroxylase 2 messenger RNA,

Puneet Seth
Objective Scleroderma (systemic sclerosis [SSc]) is a complex connective tissue disorder characterized by hardening and thickening of the skin. One hallmark of scleroderma is excessive accumulation of collagen accompanied by increased levels of pyridinoline collagen crosslinks derived from hydroxylysine residues in the collagen telopeptide domains. Lysyl hydroxylase 2 (LH2), an important alternatively spliced enzyme in collagen biosynthesis, acts as a collagen telopeptide hydroxylase. Changes in the pattern of LH2 alternative splicing, favoring increased inclusion of the alternatively spliced LH2 exon 13A, thereby increasing the levels of the long transcript of LH2 (LH2[long]), are linked to scleroderma disease. This study was undertaken to examine the role played by RNA binding protein Fox-2 in regulating exon 13A inclusion, which leads to the generation of scleroderma-associated LH2(long) messenger RNA (mRNA). Methods Phylogenetic sequence analysis of introns flanking exon 13A was performed. A tetracycline-inducible system in T-Rex 293 cells was used to induce Fox-2 protein, and endogenous LH2(long) mRNA was determined by reverse transcriptase,polymerase chain reaction. An LH2 minigene was designed, validated, and used in Fox-2 overexpression and mutagenesis experiments. Knockdown of Fox-2 was performed in mouse embryonic fibroblasts and in fibroblasts from SSc patients. Results Overexpression of Fox-2 enhanced the inclusion of exon 13A and increased the generation of LH2(long) mRNA, whereas knockdown of Fox-2 decreased LH2(long) transcripts. Mutational analysis of an LH2 minigene demonstrated that 2 of the 4 Fox binding motifs flanking LH2 exon 13A are required for inclusion of exon 13A. In early passage fibroblasts derived from patients with scleroderma, the knockdown of Fox-2 protein significantly decreased the endogenous levels of LH2(long) mRNA. Conclusion Our findings indicate that Fox-2 plays an integral role in the regulation of LH2 splicing. Knockdown of Fox-2 and other methods to decrease the levels of fibrosis-associated LH2(long) mRNA in primary scleroderma cells may suggest a novel approach to strategies directed against scleroderma. [source]

Regioselective Enzymatic Diol Esterification in Batch and Fixed-Bed Adsorptive Reactors: Experiments and Modeling

Cristiano Migliorini
The dynamic behavior of batch and fixed-bed adsorptive reactors is studied for the enzyme-catalyzed regioselective esterification of propionic acid and 2-ethyl-1,3-hexanediol in hexane. The reaction is equilibrium-limited with an apparent equilibrium constant of 0.6 ± 0.1 at 22 °C. Moreover, accumulation of water produced in the reaction onto the biocatalyst causes a decrease in the catalytic activity. As a result, improvements in both reaction rate and final conversion can be achieved by operating in an adsorptive-reactor mode. Control of water in the reactor is achieved with a catalytically inert ion-exchange resin in Na-form. The resin prevents an excessive accumulation of water on the biocatalyst and reduces equilibrium limitations. The thermodynamic activity of water is identified as a key parameter for the design of such reactors. A mathematical model capable of predicting the water activity as a function of the varying concentrations of reactants and products is thus developed and found to successfully predict the experimental behavior observed in laboratory reactors. Substantial improvements in performance predicted by the model are seen experimentally in batch reactions and during the transient operation of continuous-flow fixed-bed reactors combining adsorptive and catalytic functions. [source]

Keloid-derived fibroblasts show increased secretion of factors involved in collagen turnover and depend on matrix metalloproteinase for migration

M. Fujiwara
Summary Background, ,A keloid is a specific skin lesion that expands beyond the boundaries of the original injury as it heals. Histologically, it is characterized by the excessive accumulation of collagen. However, the reasons for the expansion and the invasive nature of keloids remain unknown. Objectives, We evaluated collagen degradation and migration by cultured keloid fibroblasts based on the assumption that these variables were of functional relevance to the expanding and invasive nature of keloid lesions. Methods, Collagen production was investigated by the detection of type 1 collagen (procollagen type 1C peptide: P1P). Matrix metalloproteinase (MMP)-1 (interstitial collagenase) and MMP-2 (gelatinase-A), were investigated as elements of the collagen degradation system. Enzyme immunoassays were performed to measure the production of P1P, MMP-1, MMP-2, and tissue inhibitor of metalloproteinase (TIMP)-1. To assess the production of MMP-2 its gelatinolytic activity was measured by zymography using gelatin-containing gels. The participation of transforming growth factor-,1 (TGF-,1) in the production and degradation of collagen was also investigated. Finally, the migratory activity of keloid fibroblasts was evaluated using a colony dispersion assay. Results, The production of type 1 collagen, MMP-1, MMP-2, and TIMP-1 by keloid fibroblasts was 3-fold, 6-fold, 2·4-fold, and 2-fold greater than that of normal dermal fibroblasts, respectively. Production of P1P was increased when TGF-,1 was added to cultures of keloid fibroblasts, while it was decreased when anti-TGF-,1 antibody was added to the cultures. In contrast, the production of MMP-1 was decreased by the addition of TGF-,1 to cultured keloid fibroblasts, while it was increased when anti-TGF-,1 antibody was added to the cultures. The production of MMP-2 increased after treatment with TGF-,1, but did not change significantly when anti-TGF-,1 antibody was added to the cultures. Production of TIMP-1 did not change significantly when either TGF-,1 or anti-TGF-,1 antibody was added to the cultures. Keloid fibroblasts showed a 2·5-fold increase of migratory activity compared with normal dermal fibroblasts, while the migratory activity of these fibroblasts was reduced to the control level by treatment with a broad-spectrum MMP inhibitor (GM 6001). Conclusions, Cultured keloid fibroblasts showed increased production of collagen and MMPs, and TGF-,1 played a role in this regulation of production. In addition, increased production of MMPs had a role in the high migratory activity of cultured keloid fibroblasts. [source]

1334: Autofluorescence: new tool to follow dry eye AMD?

Purpose In the pathophysiolgy of dry (atrophic) age related macular degeneration (AMD) aging of the retinal pigment epithelium (RPE) plays a key role. Accumulation of lipofuscin granules in the RPE cells represents a common downstream pathogenetic pathway in AMD. Lipofuscin is derived from chemically modified residues of incompletely digested photoreceptor outer segment discs. Detection of lipofuscin in vivo is possible by using fundus autofluorescence (FAF) imaging. The clinical application and possible implications of autofluorescence imaging in dry AMD will be discussed. Methods When stimulated with light in the blue to green range, lipofuscin granules emit a characteristic yellow fluorescence. FAF imaging using a scanning laser ophthalmoscope allows visualization of the topographic distribution of lipofuscin over large retinal areas. Examples of FAF images will be presented to demonstrate various FAF patterns and to discuss the clinical significance of these findings. Results In areas of geographic atrophy FAF images show very low autofluorescence intensity. This is due to the loss of RPE cells including the lipofuscin granules. In the junctional zone between atrophic and normal retina, levels of increased autofluorescence intensity may occur due to excessive accumulation of lipofuscin in the RPE cells. Longitudinal observations further suggest that the extension of the total area with increased autofluorescence intensity surrounding atrophy at baseline has a strong positive correlation with atrophy progression rate over time. Conclusion FAF imaging is an important diagnostic tool to follow the progression of dry AMD and other degenerative macular diseases and should always be considered in cases were the status of the RPE is unknown. [source]