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1.
Nanotechnology ; 29(26): 265701, 2018 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-29557787

RESUMO

The stability of silver nanoplatelet (NP) suspensions prepared with different concentrations of trisodium citrate (TSC) was studied by depolarized dynamic light scattering (DDLS) and UV-vis spectrometry. The morphology of the nanoparticles, as well as the color and stability of the sols, are tuned by the concentration of the capping agent. The nanoparticles prepared with high TSC concentration (>10-4 M) are blue triangular NPs showing a slight truncation of the tips with aging. When low TSC concentrations are used, the color of the sols changes from blue to yellow with aging time and a strong modification of the morphology occurs: the nanoparticle shape changes from triangular to spherical. Remarkably, they show a high degree of anisotropy. The aging process was followed by the UV-vis spectra and by measuring the rotational diffusion coefficient by DDLS, providing information on the nanoparticle size and shape evolution. The high intensity of depolarized signal and the high value of rotational diffusion coefficient suggest that the aging process increases the thickness and the roughness of the nanoparticles.

2.
Am J Transplant ; 16(5): 1421-40, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26602379

RESUMO

In an era where we are becoming more reliant on vulnerable kidneys for transplantation from older donors, there is an urgent need to understand how brain death leads to kidney dysfunction and, hence, how this can be prevented. Using a rodent model of hemorrhagic stroke and next-generation proteomic and metabolomic technologies, we aimed to delineate which key cellular processes are perturbed in the kidney after brain death. Pathway analysis of the proteomic signature of kidneys from brain-dead donors revealed large-scale changes in mitochondrial proteins that were associated with altered mitochondrial activity and morphological evidence of mitochondrial injury. We identified an increase in a number of glycolytic proteins and lactate production, suggesting a shift toward anaerobic metabolism. Higher amounts of succinate were found in the brain death group, in conjunction with increased markers of oxidative stress. We characterized the responsiveness of hypoxia inducible factors and found this correlated with post-brain death mean arterial pressures. Brain death leads to metabolic disturbances in the kidney and alterations in mitochondrial function and reactive oxygen species generation. This metabolic disturbance and alteration in mitochondrial function may lead to further cellular injury. Conditioning the brain-dead organ donor by altering metabolism could be a novel approach to ameliorate this brain death-induced kidney injury.


Assuntos
Biomarcadores/análise , Morte Encefálica/fisiopatologia , Rim/fisiopatologia , Metabolômica/métodos , Estresse Oxidativo/genética , Proteômica/métodos , Animais , Masculino , Ratos , Ratos Endogâmicos F344 , Transdução de Sinais
3.
Kidney Int Rep ; 9(5): 1473-1483, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38707804

RESUMO

Introduction: Delayed graft function (DGF) is often defined as the need for dialysis treatment in the first week after a kidney transplantation. This definition, though readily applicable, is generic and unable to distinguish between "types" of DGF or time needed to recover function that may also significantly affect longer-term outcomes. We aimed to profile biological pathways in donation after circulatory death (DCD) kidney donors that correlate with DGF and different DGF durations. Methods: A total of N = 30 DCD kidney biopsies were selected from the UK Quality in Organ Donation (QUOD) biobank and stratified according to DGF duration (immediate function, IF n = 10; "short-DGF" (1-6 days), SDGF n = 10; "long-DGF" (7-22 days), LDGF n = 10). Samples were matched for donor and recipient demographics and analyzed by label-free quantitative (LFQ) proteomics, yielding identification of N = 3378 proteins. Results: Ingenuity pathway analysis (IPA) on differentially abundant proteins showed that SDGF kidneys presented upregulation of stress response pathways, whereas LDGF presented impaired response to stress, compared to IF. LDGF showed extensive metabolic deficits compared to IF and SDGF. Conclusion: DCD kidneys requiring dialysis only in the first week posttransplant present acute cellular injury at donation, alongside repair pathways upregulation. In contrast, DCD kidneys requiring prolonged dialysis beyond 7 days present minimal metabolic and antioxidant responses, suggesting that current DGF definitions might not be adequate in distinguishing different patterns of injury in donor kidneys contributing to DGF.

4.
J Nanosci Nanotechnol ; 13(7): 4744-51, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23901499

RESUMO

Nanofibers of conducting polymers, as polyaniline (PANI), have received a great deal of attention by the scientific community for their potential applications (electronic, magnetic, biomedical, optical fields). Recently the electrospinning has emerged as a promising technique to produce wires and fibers of polymers with diameters ranging from 10 nm to 10 microm. PANI shows poor processability by electrospinning due to its low solubility in common solvents. However, it is possible to spin polyaniline nanofibers adding another polymer to the organic solutions, generally an insulator, necessary to increase the viscosity of the polymeric solution to be spun. Unfortunately, the presence of an insulator copolymer decreases the fibers conductivity. The key factor to obtain fibers of good quality (high conductivity and a narrow distribution of the diameters) is to reduce the amount of insulator copolymer in the spun process. Accordingly, we prepared raw PANI following different synthetic methods to be compared, aiming at the best optimized protocol in terms of easy solubility and enhanced spinning behavior of the polymers achieved. All the materials have been characterized by FT-IR and UV-VIS spectroscopies. The spun samples obtained have been characterized by SEM to evaluate the fiber morphology and complex impedance spectroscopy (EIS) in order to measure the electrical conductivity.


Assuntos
Compostos de Anilina/química , Cristalização/métodos , Eletroquímica/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Rotação , Propriedades de Superfície
5.
Front Transplant ; 2: 1166661, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-39055309

RESUMO

Introduction: Currently there is an urgent need to translate interventions that may be beneficial to marginal donor kidneys prior to transplant, to improve their quality from bench to bedside. This project investigated the effects of CC-4066, a potent dual inhibitor of cyclophilin proteins A and D, treatment during static cold storage (SCS) in a porcine model of renal ischemia-reperfusion injury (IRI) using Normothermic Reperfusion (NR). Materials and methods: Porcine kidneys and autologous blood were retrieved in pairs from a local abattoir (n = 7). One kidney from each pair was randomly allocated to treatment and one allocated to control and flushed with preservation solution containing CC-4066 or vehicle. After 7 h of SCS kidneys underwent 3 h Normothermic Reperfusion (NR) with autologous whole blood while perfusion characteristics and samples were collected. Results: Perfusion and metabolic parameters showed similar trends and no statistical differences were observed between the groups. IL-6 showed a significant increase over time but no significant difference between groups (p-value 0.009 and 0.14 respectively, two-way ANOVA). Oxygen consumption and lactate levels were similar between groups but there was increased vacuolation on histology in the control group. Conclusions: The addition of CC-4066 during SCS of kidneys is safe and feasible and has no adverse or detrimental effects on perfusion during assessment on NR. There was no difference in cytokine levels although there was a trend towards less vacuolation on histology in the treatment group.

6.
PLoS One ; 18(6): e0287713, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37352336

RESUMO

Hypothermic machine perfusion (HMP) provides preservation superior to cold storage and may allow for organ assessment prior to transplantation. Since flavin mononucleotide (FMN) in perfusate has been proposed as a biomarker of organ quality during HMP of donor livers, the aim of this study was to validate FMN as a biomarker for organ quality in the context of HMP preserved kidneys. Perfusate samples (n = 422) from the paired randomised controlled COPE-COMPARE-trial, comparing HMP with oxygenation (HMPO2) versus standard HMP in kidneys, were used. Fluorescence intensity (FI) was assessed using fluorescence spectroscopy (excitation 450nm; emission 500-600nm) and validated by fluorospectrophotometer and targeted liquid chromatography mass spectrometry (LC-MS/MS). Fluorescence intensity (FI)(ex450;em500-600) increased over time during machine perfusion in both groups (p<0.0001). This increase was similar for both groups (p = 0.83). No correlation, however, was found between FI(ex450;em500-600) and post-transplant outcomes, including day 5 or 7 serum creatinine (p = 0.11; p = 0.16), immediate graft function (p = 0.91), creatinine clearance and biopsy-proven rejection at one year (p = 0.14; p = 0.59). LC-MS/MS validation experiments of samples detected FMN in only one perfusate sample, whilst the majority of samples with the highest fluorescence (n = 37/38, 97.4%) remained negative. In the context of clinical kidney HMP, fluorescence spectroscopy unfortunately appears to be not specific and probably unsuitable for FMN. This study shows that FMN does not classify as a clinically relevant predictive biomarker of kidney graft function after transplantation.


Assuntos
Mononucleotídeo de Flavina , Preservação de Órgãos , Cromatografia Líquida , Preservação de Órgãos/métodos , Espectrometria de Massas em Tandem , Diálise Renal , Rim , Perfusão/métodos , Biomarcadores
7.
Ann Trop Med Parasitol ; 105(1): 25-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21294946

RESUMO

Each year in Spain, the number of Latin American immigrants who present with chronic Trypanosoma cruzi infection increases. Although gastro-intestinal abnormalities are not as common as cardiomyopathy in such infection, they can still lead to an impaired quality of life. In a recent study based in Madrid, the frequencies of gastro-intestinal involvement in a cohort of Latin American immigrants infected with T. cruzi, and the role of early diagnostic techniques in the detection of such involvement, were explored. Between January 2003 and April 2009, all Latin Americans who attended the Tropical Medicine Unit of the Hospital Universitario Ramón y Cajal were tested for T. cruzi infection, in IFAT and ELISA. Each subject found both IFAT- and ELISA-positive was considered to be infected (chronically) and checked for symptoms indicative of Chagas disease. Each infected subject giving informed consent was investigated further, using an electrocardiogram, an echocardiogram and oesophageal manometry. Between January 2003 and June 2008, every infected subject who consented was also explored using a barium swallow and barium enema. After July 2008, however, only subjects showing oesophageal and/or colonic symptoms were investigated in this manner. Of the 248 patients found infected with T. cruzi, 118 underwent oesophageal manometry, 75 a barium enema and 48 a barium swallow. Thirteen (11%) showed evidence of oesophageal involvement (incomplete relaxation of the lower oesophageal sphincter; three cases) or bowel involvement (five cases of dolichosigma, three of dolichocolon and two of megacolon). Only six of these 13 had any gastro-intestinal symptoms (all six were suffering from constipation). None of the barium swallows revealed any pathology. It appears that oesophageal manometry can reveal mild abnormalities not detected by barium swallow, even in asymptomatic patients, while barium enemas are useful in the detection of colonic involvement.


Assuntos
Sulfato de Bário , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Enema , Esôfago/fisiopatologia , Trypanosoma cruzi/isolamento & purificação , Adolescente , Adulto , Idoso , Anticorpos Antiprotozoários/isolamento & purificação , Antígenos de Protozoários/isolamento & purificação , Doença de Chagas/metabolismo , Doença de Chagas/fisiopatologia , Meios de Contraste , Ecocardiografia , Eletrocardiografia , Ensaio de Imunoadsorção Enzimática , Feminino , Hispânico ou Latino , Humanos , América Latina/etnologia , Masculino , Manometria , Pessoa de Meia-Idade , Prevalência , Índice de Gravidade de Doença , Espanha/epidemiologia , Migrantes , Trypanosoma cruzi/imunologia , Trypanosoma cruzi/patogenicidade , Adulto Jovem
8.
Science ; 171(3976): 1173-5, 1971 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-4100463

RESUMO

Developmental behaviors were studied in monkeys subjected to asphyxia at birth. Visual depth perception, visual pla ing, and locomotion appeared significantly later than in nonasphyxiated monkeys. After these behaviors had been established in asphyxiates, however, there was little difference from those observed in normal monkeys. These results were compared with reports of permanent learning deficits that occur in monkeys asphyxiated at birth for similar periods of time. Such comparison suggests that the neural structures responsible for the developmental behaviors studied are not damaged by asphyxia to the same extent as those for acquisition. Delay in development may be an early indication of brain damage with subsequent mental retardation.


Assuntos
Animais Recém-Nascidos , Asfixia Neonatal/fisiopatologia , Comportamento Animal , Percepção de Profundidade , Amnésia/etiologia , Animais , Encefalopatias/complicações , Deficiências do Desenvolvimento/diagnóstico , Humanos , Hipóxia Encefálica/complicações , Recém-Nascido
9.
Science ; 172(3989): 1221, 1971 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-17747350

RESUMO

In "Developmental behaviors: delayed appearance in monkeys asphyxiated at birth" by J. A. Sechzer et al. (19 Mar., p. 1173), the last two lines of column 1 and the first five lines of column 2, page 1175, should read "Deficits in learning and memory (10, 11) when compared with the establishment of these developmental behaviors (although significantly delayed) suggest that brain damage by neonatal asphyxia can result in a degree of dissociation..."

10.
Sci Rep ; 9(1): 84, 2019 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-30643155

RESUMO

In this study, for the first time, we demonstrated the presence of microRNAs and extracellular vesicles in human blastocoel fluid. The bioinformatic and comparative analyses identified the biological function of blastocoel fluid microRNAs and suggested a potential role inside the human blastocyst. We found 89 microRNAs, expressed at different levels, able to regulate critical signaling pathways controlling embryo development, such as pluripotency, cell reprogramming, epigenetic modifications, intercellular communication, cell adhesion and cell fate. Blastocoel fluid microRNAs reflect the miRNome of embryonic cells and their presence, associated with the discovery of extracellular vesicles, inside blastocoel fluid, strongly suggests their important role in mediating cell communication among blastocyst cells. Their characterization is important to better understand the earliest stages of embryogenesis and the complex circuits regulating pluripotency. Moreover, blastocoel fluid microRNA profiles could be influenced by blastocyst quality, therefore, microRNAs might be used to assess embryo potential in IVF cycles.


Assuntos
Blastocisto/metabolismo , Líquidos Corporais/química , Vesículas Extracelulares/metabolismo , MicroRNAs/análise , Transcriptoma , Biologia Computacional , Humanos , Anotação de Sequência Molecular
11.
Int J Biochem Cell Biol ; 44(8): 1223-31, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22565169

RESUMO

Peroxiredoxin 2 has immune regulatory functions, but its expression in human peripheral blood lymphocytes and levels in extracellular fluid in healthy subjects and rheumatoid arthritis patients are poorly described. In the present study, the median intracellular peroxiredoxin 2 protein content of lymphocytes from rheumatoid arthritis patients was more than two-fold higher compared with healthy subjects' lymphocytes. Intracellular peroxiredoxin 3 levels were similar in healthy and rheumatoid arthritis lymphocytes. Flow cytometry detected peroxiredoxin 2 on the surface of ca. 8% of T cells and ca. 56% of B cells (median % values) of all subjects analyzed. Exofacial thioredoxin-1 was also observed. In the total lymphocyte population from rheumatoid arthritis patients, few cells (median, 6%) displayed surface peroxiredoxin 2. In contrast, a significantly increased proportion of interleukin-17(+ve) lymphocytes were exofacially peroxiredoxin 2(+ve) (median, 39%). Prdx2 was also detected in human extracellular fluids. We suggest that crucial inflammatory cell subsets, i.e. interleukin-17(+ve) T cells, exhibit increased exofacial redox-regulating enzymes and that peroxiredoxin 2 may be involved in the persistence of pro-inflammatory cells in chronic inflammation.


Assuntos
Artrite Reumatoide/metabolismo , Linfócitos/metabolismo , Peroxirredoxinas/metabolismo , Adulto , Idoso , Artrite Reumatoide/genética , Linfócitos B/metabolismo , Western Blotting , Líquido Extracelular/metabolismo , Feminino , Citometria de Fluxo , Humanos , Interleucina-17/metabolismo , Líquido Intracelular/metabolismo , Masculino , Pessoa de Meia-Idade , Oxirredução , Peroxirredoxina III/genética , Peroxirredoxina III/metabolismo , Peroxirredoxinas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T/metabolismo , Tiorredoxinas/genética , Tiorredoxinas/metabolismo
14.
Biochemistry ; 39(45): 13695-702, 2000 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-11076508

RESUMO

Ferredoxin (Fd) and ferredoxin:NADP(+) reductase (FNR) from Anabaena function in photosynthetic electron transfer (et). The et interaction between the FNR charge-reversal mutant E139K and Fd at 12 mM ionic strength (mu) is extremely impaired relative to the reaction with wt FNR, and the dependency of k(obs) on E139K concentration shows strong upward curvature at protein concentrations > or = 10 microM. However, at values of mu > or = 200 mM, reaction rates approach those of wild-type FNR, and normal saturation kinetics are observed. For the E139Q mutant, which is also significantly impaired in its et interaction with Fd at low FNR concentrations and low mu values, the dependency of k(obs) on E139Q concentration shows a smaller degree of upward curvature at mu = 12 and 100 mM and shows saturation kinetics at higher values of mu. wt FNR and the E139D mutant both show a slight amount of upward curvature at FNR concentrations >30 microM at mu = 12 mM but show the expected saturation kinetics at higher values of mu. These results are explained by a mechanism in which the mutual orientation of the proteins in the complex formed at low ionic strength with the E139K mutant is so far from optimal that it is almost unreactive. At increased E139K concentrations, the added mutant FNR reacts via a collisional interaction with the reduced Fd present in the unreactive complex. The et reactivity of the low ionic strength complexes depends on the particular amino acid substitution, which via electrostatic interactions alters the specific geometry of the interface between the two proteins. The presence of a negative charge at position 139 of FNR allows the most optimal orientations for et at ionic strengths below 200 mM.


Assuntos
Substituição de Aminoácidos , Anabaena/metabolismo , Ferredoxina-NADP Redutase/metabolismo , Ferredoxinas/metabolismo , Ácido Glutâmico/metabolismo , Substituição de Aminoácidos/genética , Anabaena/enzimologia , Anabaena/genética , Dicroísmo Circular , Sequência Conservada , Ferredoxina-NADP Redutase/genética , Ferredoxinas/genética , Ácido Glutâmico/genética , Glutamina/genética , Cinética , Lisina/genética , Concentração Osmolar , Oxirredução , Fotólise , Eletricidade Estática
15.
J Biol Chem ; 276(29): 27498-510, 2001 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-11342548

RESUMO

In the ferredoxin-NADP(+) reductase (FNR)/ferredoxin (Fd) system, an aromatic amino acid residue on the surface of Anabaena Fd, Phe-65, has been shown to be essential for the electron transfer (ET) reaction. We have investigated further the role of hydrophobic interactions in complex stabilization and ET between these proteins by replacing three hydrophobic residues, Leu-76, Leu-78, and Val-136, situated on the FNR surface in the vicinity of its FAD cofactor. Whereas neither the ability of FNR to accept electrons from NADPH nor its structure appears to be affected by the introduced mutations, different behaviors with Fd are observed. Thus, the ET interaction with Fd is almost completely lost upon introduction of negatively charged side chains. In contrast, only subtle changes are observed upon conservative replacement. Introduction of Ser residues produces relatively sizable alterations of the FAD redox potential, which can explain the modified behavior of these mutants. The introduction of bulky aromatic side chains appears to produce rearrangements of the side chains at the FNR/Fd interaction surface. Thus, subtle changes in the hydrophobic patch influence the rates of ET to and from Fd by altering the binding constants and the FAD redox potentials, indicating that these residues are especially important in the binding and orientation of Fd for efficient ET. These results are consistent with the structure reported for the Anabaena FNR.Fd complex.


Assuntos
Anabaena/enzimologia , Ferredoxina-NADP Redutase/metabolismo , Ferredoxinas/metabolismo , Flavina-Adenina Dinucleotídeo/fisiologia , Família Multigênica , Sequência de Aminoácidos , Transporte de Elétrons , Ferredoxina-NADP Redutase/química , Flavina-Adenina Dinucleotídeo/química , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Oxirredução , Conformação Proteica , Homologia de Sequência de Aminoácidos
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