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111.
Iron-based phosphorus chelator: Risk of iron deposition and action on bone metabolism in uremic rats
Wander Barros do Carmo Brbara Bruna Abreu Castro Luísa Cardoso Manso Priscylla Aparecida Vieira do Carmo Clvis Antnio Rodrigues Melani Ribeiro Custdio Vanda Jorgetti Helady Sanders-Pinheiro 《Experimental biology and medicine (Maywood, N.J.)》2022,247(5):446
Phosphate chelators are frequently used in patients with chronic kidney disease (CKD). New iron-based chelators remain understudied and offer a promising therapeutic option for the control of bone and mineral disorders of chronic kidney disease (BMD-CKD). We assessed the effect of the phosphorus chelator, chitosan-iron III (CH-FeCl), compared to calcium carbonate (CaCO3) in BMD-CKD and the potential iron overload in uremic rats. Thirty-two animals were divided into four groups, namely the control, CKD, CKD/CH-FeCl, and CKD/CaCO3 groups. CKD was induced by adding 0.75% (4 weeks) and 0.1% (3 weeks) adenine to the diet. The chelators were administered from week 3 through week 7. The renal function, BMD-CKD markers, and histomorphometry of the femur were assessed at week 7. The CKD group showed a significant increase in creatinine (83.9 ± 18.6 vs. 41.5 ± 22.1 µmol/L; P = 0.001), phosphate (3.5 ± 0.8 vs. 2.2 ± 0.2 mmol/L; P = 0.001), fractional excretion of phosphorus (FEP) (0.71 ± 0.2 vs. 0.2 ± 0.17; P = 0.0001), and FGF23 (81.36 ± 37.16 pg/mL vs. 7.42 ± 1.96; P = 0.011) compared to the control group. There was no accumulation of serum or bone iron after the use of CH-FeCl. The use of chelators reduced the FEP (control: 0.71 ± 0.20; CKD/CH-FeCl: 0.40 ± 0.16; CKD/CaCO3 0.34 ± 0.15; P = 0.001), without changes in the serum FGF23 and parathyroid hormone levels. Histomorphometry revealed the presence of bone disease with high remodeling in the uremic animals without changes with the use of chelators. The CH-FeCl chelator was efficient in reducing the FEP without iron accumulation, thereby paving the way for the use of this class of chelators in clinical settings in the future. 相似文献
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113.
An amyloid(1-40) solution rich in coil, turn, and alpha-helix, but poor in beta-sheet, develops monolayers with a high beta-sheet content when spread at the air-water interface. These monolayers are resistant to repeated compression-dilatation cycles and interaction with trifluoroethanol. The secondary structure motifs were detected by circular dichroism (CD) in solution and with infrared reflection-absorption spectroscopy (IRRAS) at the interface. Hydrophobic influences are discussed for the structure conversion in an effort to understand the completely unknown reason for the natural change of the normal prion protein cellular (PrP(C)) into the abnormal prion protein scrapie (PrP(Sc)). 相似文献
114.
Biofilm physiology is established under a low growth rate. The morphogene bolA is mostly expressed under stress conditions or in stationary phase, suggesting that bolA could be implicated in biofilm development. In order to verify this hypothesis, we tested the effect of bolA on biofilm formation. Overexpression of bolA induces biofilm development, while bolA deletion decreases biofilms. 相似文献
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Genome size displays an important variability between species without any direct link to complexity. This paradox, so-called "C value paradox", now becomes understood as resulting from a differential abundance of numerous repeated sequences, among which transposable elements. Genomes indeed contain a important proportion of such sequences (95 % of DNA in man, about 45 % of which are transposable elements, up to 99 % of DNA in some plants). While most investigations until now are focalized on genes or coding sequences, which thus represent a small part of the genome, more attention now is dedicated on so-called non-coding sequences. Transposable elements, which are capable of moving around in genomes, inducing mutations, chromosomal rearrangements, gene expression regulations, thus appear as major actors in diversity and evolution. We present here a brief review of the most prominent acquisition in this expanding domain. 相似文献
117.
Cortez EV Pessoa A das Graças de Almeida Felipe M Roberto IC Vitolo M 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,807(1):47-54
The intracellular enzymes xylose reductase (XR, EC 1.1.1.21) and xylitol dehydrogenase (XD, EC 1.1.1.9) from Candida guilliermondii, grown in sugar cane bagasse hydrolysate, were separated by reversed micelles of cetyl trimethyl ammonium bromide (CTAB) cationic surfactant. An experimental design was employed to optimize the extraction conditions of both enzymes. Under these conditions (temperature = 5 degree C, hexanol: isooctane proportion = 5% (v/v), 22 %, surfactant concentration = 0.15M, pH = 7.0 and electrical conductivity = 14 mScm(-1)) recovery values of about 100 and 80% were achieved for the enzymes XR and XD, respectively. The purity of XR and XD increased 5.6- and 1.8-fold, respectively. The extraction process caused some structural modifications in the enzymes molecules, as evidenced by the alteration of K(M) values determined before and after extraction, either in regard to the substrate (up 35% for XR and down 48% for XD) or cofactor (down 29% for XR and up 11% for XD). However, the average variation of V(max) values for both enzymes was not higher than 7%, indicating that the modified affinity of enzymes for their respective substrates and cofactors, as consequence of structural modifications suffered by them during the extraction, are compensated in some extension. This study demonstrated that liquid-liquid extraction by CTAB reversed micelles is an efficient process to separate the enzymes XR and XD present in the cell extract, and simultaneously increase the enzymatic activity and the purity of both enzymes produced by C. guilliermondii. 相似文献
118.
Local delivery of CpG oligodeoxynucleotides induces rapid changes in the genital mucosa and inhibits replication,but not entry,of herpes simplex virus type 2 总被引:10,自引:0,他引:10
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Mucosal surfaces are the entry sites for the vast majority of infectious pathogens and provide the first line of defense against infection. In addition to the epithelial barrier, the innate immune system plays a key role in recognizing and rapidly responding to invading pathogens via innate receptors, such as Toll-like receptors (TLR). Bacterial CpG DNA, a potent activator of innate immunity, is recognized by TLR9. Here, we confirm that local mucosal, but not systemic, delivery of CpG oligodeoxynucleotides (ODN) to the genital tract protects mice from a subsequent lethal vaginal herpes simplex virus type 2 (HSV-2) challenge. Since these effects were so local in action, we examined the genital mucosa. Local delivery of CpG ODN induced rapid proliferation and thickening of the genital epithelium and caused significant recruitment of inflammatory cells to the submucosa. Local CpG ODN treatment also resulted in inhibition of HSV-2 replication but had no effect on HSV-2 entry into the genital mucosa. CpG ODN-induced protection against HSV-2 was not associated with early increases in gamma interferon (IFN-gamma) secretion in the genital tract, and CpG ODN-treated IFN-gamma(-/-) mice were protected from subsequent challenge with a lethal dose of HSV-2. Treatment of human HEK-293 cells transfected with murine TLR9 showed that the antiviral activity of CpG ODN was mediated through TLR9. These studies suggest that local induction of mucosal innate immunity can provide protection against sexually transmitted infections, such as HSV-2 or possibly human immunodeficiency virus, at the mucosal surfaces. 相似文献
119.
The misfolding of the amyloid peptide, which is the result of a well-known alpha-to-beta transition, causes neurodegenerative disorder. Fluorinated alcohols have been described in the literature as potent solvents which can refold the beta-conformation. The present studies demonstrate the effectiveness of differently fluorinated alcohols for the beta-to-alpha refolding process on fibrillar aggregated amyloid beta(1-40). The regenerated helical structure is shown to be maintained in the absence of the fluoroalcohols, a behaviour which was found to contrast with immunoglobulin. We interpret this difference on the basis of the hydrophilic/hydrophobic domains in the amyloid sequence and present some speculations regarding the free-energy levels of the folded states of both proteins. The effect of the -CF(3) group on the observed conformational changes is interpreted as a result of alterations of the hydration shell of the peptides. Moreover, based on the results achieved with fluoroalcohols, we have used novel fluorinated amphiphiles possessing blood-compatibility properties and studied their effect on amyloid beta(1-40). First results point in the direction of a beta-to-alpha transition. Therefore, the use of fluorine groups in the development of new drugs is considered a new possibility requiring further investigation for the prevention of amyloidosis. 相似文献
120.
Edge effect is an inherent problem when using trapping grids to estimate density of small mammals, resulting in a sampling
area larger than the area of the grid. Distances between captures of individuals are used to estimateA(W), the effective sampling area of a trapping grid, but grid size sets a limit for the largest detectable distance. The spool-and-line
technique is proposed here as a new method to estimateA(W). Movement distances based on the spool-and-line technique were compared to similar movement distances based on capture-recapture
of three species of marsupials of the Atlantic Forest of Brazil. Distances based on the two methods were uncorrelated, and
only ln-transformed distances based on the spool-and-line were normally distributed. The maximum distance moved (MaxD) estimated
by the spool-and-line was chosen as the more accurate and practical distance to estimate edge effect. Estimates of the effective
sampling area and densities for the common opossumDidelphis aurita (Wied-Neuwied, 1826), were compared using MaxD based on spool-and-line (MaxDs p o o l ) , capture-recapture (MaxDcap), and also the distance between traps (DT). MaxDspool reflected more accurately density variation between seasons. Movement distances of small mammals based on the spool-and-line
technique permit more accurate estimates of density and its dynamics. 相似文献