Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Rep ; 10(1): 11813, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678243

RESUMO

We propose a innovative concept to boost the electrochemical performance of cathode composite electrodes using surface-modified carbons with hydrophilic moieties to increase their dispersion in a Lithium Nickel Manganese Cobalt Oxide (NMC) cathode and in-situ generate Li-rich carbon surfaces. Using a rapid aqueous process, the hydrophilic carbon is effectively dispersed in NMC particles followed by the conversion of its acid surface groups (e.g. -COOH), which interact with the NMC particles due to their basicity, into grafted Li salt (-COO-Li+). The solid-state batteries prepared using the cathode composites with surface-modified carbon exhibit better electrochemical performance. Such modified carbons led to a better electronic conduction path as well as facilitating Li+ ions transfer at the carbon/NMC interface due to the presence of lithiated carboxylate groups on their surface.

2.
Sci Rep ; 10(1): 3812, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32123203

RESUMO

This work presents an alternative method for fabricating Li-ion electrodes in which the use of aluminum/copper current collectors and expensive binders is avoided. Low-cost natural cellulose fibers with a 2-mm length are employed as binder and support for the electrode. The objective of this method is to eliminate the use of heavy and inactive current collector foils as substrates and to replace conventional costly binders with cellulose fibers. Moreover, no harmful solvents, such as N-methylpyrrolidone, are employed for film fabrication. Water-soluble carbons are also utilized to reduce the preparation time and to achieve a better repartition of carbon in the electrode, thus improving the electrochemical performance. Flexible and resistant LiFePO4 (LFP), Li4Ti5O12 (LTO), organic 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), and graphite electrodes are obtained with active mass loadings similar to those obtained by the current casting method. The initial discharge capacity of approximately 130 mAh·g-1 at 2 C is obtained for an LFP/LTO paper battery with an approximately 91.6% capacity retention after 1000 cycles. An all-organic prelithiated PTCDA/graphite cell without a transition metal is prepared and electrochemically tested. It is one of the first self-standing batteries that is composed of organic redox active molecules and biodegradable components reported in literature.

3.
Genes Immun ; 16(5): 311-20, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25973757

RESUMO

Systemic lupus erythematosus is a complex autoimmune disorder characterized by the production of pathogenic anti-nuclear antibodies. Previous work from our laboratory has shown that the introgression of a New Zealand Black-derived chromosome 4 interval onto a lupus-prone background suppresses the disease. Interestingly, the same genetic interval promoted the expansion of both Natural Killer T- and CD5(+) B cells in suppressed mice. In this study, we show that ablation of NKT cells with a CD1d knockout had no impact on either the suppression of lupus or the expansion of CD5(+) B cells. On the other hand, suppressed mice had an expanded population of IL-10-producing B cells that predominantly localized to the CD5(+)CD1d(low) compartment. The expansion of CD5(+) B cells negatively correlated with the frequency of pro-inflammatory IL-17 A-producing T-cells and kidney damage. Adoptive transfer with a single injection of total B cells with an enriched CD5(+) compartment reduced the frequency of memory/activated, IFNγ-producing, and IL-17 A-producing CD4 T-cells but did not significantly reduce autoantibody levels. Taken together, these data suggest that the expansion of CD5(+) IL-10-producing B cells and not NKT cells protects against lupus in these mice, by limiting the expansion of pro-inflammatory IL-17 A- and IFNγ-producing CD4 T-cells.


Assuntos
Autoimunidade , Linfócitos B/imunologia , Antígenos CD5/metabolismo , Interleucina-10/metabolismo , Lúpus Eritematoso Sistêmico/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Antígenos CD5/genética , Memória Imunológica , Interleucina-10/genética , Camundongos , Camundongos Endogâmicos NZB
4.
Genes Immun ; 12(4): 251-62, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21307879

RESUMO

Lupus susceptibility loci on chromosome 1 have an important role in the development of autoimmunity in the New Zealand Black (NZB) mouse. We have previously shown that C57BL/6 congenic mice with an introgressed homozygous NZB chromosome 1 interval extending from ∼35 to 106 cM develop anti-nuclear antibodies and mild glomerulonephritis. In this study, we produced subcongenic mouse strains to localize the susceptibility loci in this interval and investigate how they promote autoimmunity. Our results indicate at least four susceptibility alleles and a suppressor allele. One allele is located in the 96-100 cM region and is sufficient to breach tolerance to chromatin. Addition of a second locus in the 88-96 cM interval enhances anti-dsDNA antibody production and promotes renal disease, which together with a third susceptibility allele in the 70-88 interval results in significant mortality. We further demonstrate the presence of a suppressor locus in the 35-70 or 100-102 cM interval that abrogates these phenotypes and an additional susceptibility allele in the 102-106 cM interval that restores a milder autoimmune phenotype. Several of these loci alter T-cell function. Thus, there is substantial genetic complexity in the NZB 35-106 cM interval, with disease reflecting a balance between susceptibility and suppressor loci.


Assuntos
Predisposição Genética para Doença , Lúpus Eritematoso Sistêmico/genética , Animais , Loci Gênicos , Lúpus Eritematoso Sistêmico/congênito , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NZB , Fenótipo , Linfócitos T/imunologia , Técnicas de Cultura de Tecidos
5.
J Thromb Haemost ; 7(4): 710-9, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19192108

RESUMO

BACKGROUND AND OBJECTIVES: Anti-heat shock protein (HSP)60 autoantibodies are associated with atherosclerosis and are known to affect endothelial cells in vitro. However, their role in thrombus formation remains unclear. We hypothesized that anti-HSP60 autoantibodies could potentiate thrombosis, and evaluated the effect of anti-murine HSP60 antibodies in a ferric chloride (FeCl3)-induced murine model of carotid artery injury. METHODS: Anti-HSP60, or control, IgG was administered to BALB/c mice 48 h prior to inducing carotid artery injury, and blood flow was monitored using an ultrasound probe. RESULTS: Thrombus formation was more rapid and stable in anti-HSP60 IGG-treated mice than in controls (blood flow=1.7%+/-0.6% vs. 34%+/-12.6%, P=0.0157). Occlusion was complete in all anti-HSP60 IgG-treated mice (13/13), with no reperfusion being observed. In contrast, 64% (9/14) of control mice had complete occlusion, with reperfusion occurring in 6/9 mice. Thrombi were significantly larger in anti-HSP60 IgG-treated mice (P=0.0001), and contained four-fold more inflammatory cells (P=0.0281) than in controls. Non-injured contralateral arteries of anti-HSP60 IgG-treated mice were also affected, exhibiting abnormal endothelial cell morphology and significantly greater von Willebrand factor (VWF) and P-selectin expression than control mice (P=0.0024 and P=0.001, respectively). CONCLUSIONS: In summary, the presence of circulating anti-HSP60 autoantibodies resulted in increased P-selectin and VWF expression and altered cell morphology in endothelial cells lining uninjured carotid arteries, and promoted thrombosis and inflammatory cell recruitment in FeCl3-injured carotid arteries. These findings suggest that anti-HSP60 autoantibodies may constitute an important prothrombotic risk factor in cardiovascular disease in human vascular disease.


Assuntos
Autoanticorpos/farmacologia , Chaperonina 60/imunologia , Trombose/imunologia , Animais , Arteriopatias Oclusivas/etiologia , Arteriopatias Oclusivas/imunologia , Autoanticorpos/administração & dosagem , Doenças das Artérias Carótidas/etiologia , Doenças das Artérias Carótidas/imunologia , Cloretos , Modelos Animais de Doenças , Compostos Férricos , Camundongos , Selectina-P/análise , Fluxo Sanguíneo Regional , Reperfusão , Trombose/etiologia , Fator de von Willebrand/análise
8.
Am J Kidney Dis ; 38(4): 728-35, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11576875

RESUMO

Immunoglobulin A (IgA) nephropathy is one of the most common primary types of glomerulonephritis to progress to end-stage renal disease. Its variable and often long natural history makes it difficult to predict outcome. We investigated the association of the rate of renal function decline based on the slope of creatinine clearance over time with demographic, clinical, laboratory, and histological data from 298 patients with biopsy-proven IgA nephropathy with a mean follow-up of 70 months. Using univariate analysis, urinary protein excretion at baseline and Lee pathological grading, as well as mean arterial pressure (MAP) and urinary protein excretion during follow-up, were associated with the rate of deterioration in renal function. Of these, only MAP and urinary protein excretion during follow-up were identified as independent factors by multiple linear regression analysis. The combination of best accuracy of prediction and shortest observation time using these two parameters was reached between the second and third years of follow-up. A semiquantitative method of estimating the rate of progression by using these factors was developed. These results indicate that MAP and severity of proteinuria over time are the most important prognostic indicators of IgA nephropathy. The potential relevance of the algorithm in patient management is shown.


Assuntos
Glomerulonefrite por IGA/fisiopatologia , Adolescente , Adulto , Idoso , Análise de Variância , Progressão da Doença , Feminino , Taxa de Filtração Glomerular , Glomerulonefrite por IGA/mortalidade , Glomerulonefrite por IGA/patologia , Humanos , Rim/patologia , Rim/fisiopatologia , Falência Renal Crônica/etiologia , Masculino , Pessoa de Meia-Idade , Taxa de Sobrevida
9.
Arch Pathol Lab Med ; 125(5): 631-6, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11300933

RESUMO

CONTEXT: Thin basement membrane nephropathy is recognized by a diffusely thin glomerular basement membrane (GBM) ultrastructurally. In contrast to Alport syndrome (AS), there is no GBM thickening, lamellation, or granular inclusions. Morphologically, there is overlap between thin basement membrane nephropathy and AS in female patients in whom there might be only thin GBM and no pathognomonic findings of AS. OBJECTIVE: To determine if the use of antibodies to collagen IV is helpful in making the distinction between thin basement membrane nephropathy and AS in female patients with primarily thin GBMs. DESIGN: We examined renal biopsies from 9 adult female patients with thin GBMs for the presence of alpha1, alpha3, alpha4, and alpha5 chains of type IV collagen by immunofluorescence. RESULTS: In 2 patients with segmental GBM staining, no suggestion for AS was found on physical examination or in their family history. In the remaining 7 patients with normal GBM staining, 4 had family members with end-stage renal disease of unknown etiology, raising the suspicion of X-linked or autosomal-recessive AS. Three patients were presumed to have thin basement membrane nephropathy. CONCLUSION: Segmental GBM staining for alpha3, alpha4, and alpha5 chains of type IV collagen raises the suspicion of AS in the presence of adequate controls and other supporting evidence. Normal GBM staining for alpha3, alpha4, and alpha5 chains of type IV collagen, however, does not exclude AS.


Assuntos
Anticorpos Monoclonais , Colágeno/metabolismo , Nefrite Hereditária/diagnóstico , Adulto , Membrana Basal/ultraestrutura , Colágeno/imunologia , Diagnóstico Diferencial , Feminino , Humanos , Glomérulos Renais/ultraestrutura , Microscopia Eletrônica , Microscopia de Fluorescência , Nefrite Hereditária/metabolismo , Nefrite Hereditária/patologia
10.
Ultrastruct Pathol ; 25(1): 21-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11297316

RESUMO

Angiomyolipoma (AML) is a mesenchymal neoplasm of unclear histogenesis. In addition to varying amounts of smooth muscle, adipose tissue, and blood vessels, it contains a population of clear or pale eosinophilic epithelioid cells often arranged around blood vessels. Various phenotypes of AML have been described: leiomyoma-like, lipoma-like, epithelioid, and atypical. AMLs show consistent immunopositivity for HMB-45. This has been associated with the ultrastructural observation of melanosome-like structures in rare instances. In the present study, 14 AMLs from 13 patients were analyzed by electron microscopy and immunohistochemistry to determine the appearance and nature of cells composing AMLs. Overlap between cell types (spindle smooth muscle cells, epithelioid cells, and adipocytes) was found by both electron microscopy and immunohistochemistry. Melanosomes were found in 7 tumors. The cell of origin remains mysterious. Nevertheless, the study demonstrates that the AML is likely derived from a single cell that shares homology with the pericyte.


Assuntos
Angiomiolipoma/ultraestrutura , Neoplasias Renais/ultraestrutura , Neoplasias Hepáticas/ultraestrutura , Adulto , Idoso , Angiomiolipoma/química , Antígenos de Neoplasias/análise , Biomarcadores Tumorais/análise , Células Epitelioides/química , Células Epitelioides/ultraestrutura , Feminino , Seguimentos , Humanos , Imuno-Histoquímica , Neoplasias Renais/química , Neoplasias Hepáticas/química , Masculino , Antígenos Específicos de Melanoma , Melanossomas/ultraestrutura , Microscopia Eletrônica , Pessoa de Meia-Idade , Proteínas de Neoplasias/análise
11.
Plant Physiol ; 124(3): 1251-64, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11080301

RESUMO

Antifreeze proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-antifreeze proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.


Assuntos
Proteínas Anticongelantes/genética , Quitinases/genética , Temperatura Baixa , Secale/genética , Triticum/genética , Sequência de Aminoácidos , Proteínas Anticongelantes/isolamento & purificação , Proteínas Anticongelantes/metabolismo , Sequência de Bases , Southern Blotting , Quitinases/isolamento & purificação , Quitinases/metabolismo , DNA Complementar/isolamento & purificação , Escherichia coli/metabolismo , Genoma de Planta , Dados de Sequência Molecular , RNA Mensageiro/análise , Secale/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Triticum/metabolismo
12.
Ultrastruct Pathol ; 24(4): 221-6, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11013962

RESUMO

Multiple myeloma is associated with a wide array of renal diseases that include myeloma cast nephropathy, monoclonal immunoglobulin deposition disease, amyloidosis, cryoglobulinemia, tubular dysfunction, pyelonephritis, nephrocalcinosis, urate nephropathy, and infiltration by atypical plasma cells (or myeloma cells). Filtered immunoglobulin light chains may affect both the distal and, more frequently, the proximal tubule. Tubular abnormalities in patients with plasma cell dyscrasia may be more frequent than previously thought. A patient with a plasma cell dyscrasia is described, who presented with biochemical features consistent with Fanconi syndrome. Immunoelectron microscopy performed on the renal biopsy confirmed the presence of kappa light chain immunoglobulin in intracytoplasmic crystals in proximal tubular epithelial cells. This report is one of a few demonstrating the presence of light-chain immunoglobulin in intratubular crystals in a human renal biopsy obtained from a patient with a plasma cell dyscrasia and Fanconi syndrome.


Assuntos
Síndrome de Fanconi/complicações , Síndrome de Fanconi/patologia , Paraproteinemias/complicações , Paraproteinemias/patologia , Biópsia , Medula Óssea/metabolismo , Medula Óssea/patologia , Síndrome de Fanconi/metabolismo , Humanos , Rim/metabolismo , Rim/patologia , Masculino , Microscopia Imunoeletrônica , Pessoa de Meia-Idade , Paraproteinemias/metabolismo
13.
Rapid Commun Mass Spectrom ; 14(19): 1736-45, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11006580

RESUMO

Electrospray ionization mass spectrometry (ESI-MS) was used to investigate metal ion interactions with salivary peptides histatin 3 (H3) and histatin 5 (H5). Conformational changes of these peptides in the presence of metal ions were studied using circular dichroism spectroscopy. H3 and H5 formed high affinity complexes with Cu(2+) and Ni(2+) and, to a lesser extent, with Zn(2+). Both peptides show the potential for multiple binding sites for Cu(2+) and Ni(2+) and only a single strong binding site for Zn(2+). The binding of a third Cu(2+) ion to H3 seems to enable the binding of a fourth ion to H3. The binding of a second and third Ni(2+) ion to H5 has a similar effect in enabling the binding of a fourth ion. None of the metal ions examined stabilized a regular secondary structure for either peptide. Subtle changes in overall conformation are seen with the addition of Cu(2+) to both H3 and H5.


Assuntos
Glicoproteínas/química , Histidina/química , Metais/química , Proteínas/química , Proteínas e Peptídeos Salivares/química , Sequência de Aminoácidos , Cátions Bivalentes/química , Dicroísmo Circular , Histatinas , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Dados de Sequência Molecular , Ligação Proteica , Desnaturação Proteica
14.
Ultrastruct Pathol ; 24(1): 15-21, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10721148

RESUMO

Renal diseases involving glomerular deposits of fibrillary material are an important diagnostic challenge for the ultrastructural pathologist. Two primary disorders of this type, termed "fibrillary glomerulonephritis" (characterized by fibrils measuring approximately 20 nm in diameter) and "immunotactoid glomerulopathy" (characterized by larger, microtubular deposits), have been described. The possible relatedness of these two disorders and their potential association with other systemic illnesses are subjects of current debate. Other multisystemic diseases, including amyloidosis and various forms of cryoglobulinemia, can also present with fibrillary or microtubular deposits in the kidney. Five cases are presented in which fibrillar or microtubular structures were identified in renal biopsies by ultrastructural examination. The distinction between fibrillary glomerulonephritis, immunotactoid glomerulopathy, and other processes that have similar ultrastructural features are discussed.


Assuntos
Citoesqueleto de Actina , Glomerulonefrite/patologia , Citoesqueleto de Actina/ultraestrutura , Adulto , Crioglobulinemia/patologia , Feminino , Mesângio Glomerular/ultraestrutura , Glomerulonefrite/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome Nefrótica/diagnóstico
15.
Infect Immun ; 68(3): 1243-51, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10678933

RESUMO

Tumor necrosis factor (TNF) has generally been regarded as a protective cytokine in host defense against bacterial infections. In the present study, we evaluated the role of TNF in the acute phase of infection by Yersinia enterocolitica by using mice rendered genetically deficient in TNF receptor p55 (TNFRp55(-/-)). Unexpectedly, TNFRp55(-/-) mice showed more effective resistance to the bacteria, reflected in enhanced bacterial clearance and less tissue damage, than did control C57BL/6 mice. C57BL/6 mice showed evidence of extensive apoptosis in the spleen accompanied by a selective decrease in the CD4(+)-T-cell population of splenocytes, whereas TNFRp55(-/-) mice were spared these changes. The splenocytes from TNFRp55(-/-) mice also maintained a robust gamma interferon IFN-gamma response to mitogenic stimulation, while the comparable response in C57BL/6 mice was impaired. In addition, splenocytes harvested from infected mice demonstrated lower production of interleukin-10 IL-10 in TNFRp55(-/-) mice than in C57BL/6 mice. These findings suggest that Yersinia can induce TNFRp55-mediated apoptosis of splenocytes in the acute phase of the infection and that alteration of T-cell-generated cytokines can dramatically alter the early events in host defense against this pathogen.


Assuntos
Antígenos CD/fisiologia , Apoptose , Receptores do Fator de Necrose Tumoral/fisiologia , Yersiniose/imunologia , Yersinia enterocolitica , Doença Aguda , Animais , Antígenos CD/metabolismo , Contagem de Linfócito CD4 , Interferon gama/biossíntese , Interleucina-10/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/biossíntese , Fagócitos/imunologia , Receptores do Fator de Necrose Tumoral/deficiência , Receptores do Fator de Necrose Tumoral/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral , Yersiniose/patologia
16.
Am J Kidney Dis ; 34(5): 932-6, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10561152

RESUMO

Calciphylaxis is a rare and severe calcification syndrome described mainly in patients with end-stage renal disease (ESRD) undergoing dialysis or with a renal transplant. This life-threatening condition is characterized by the abrupt onset of painful ischemic skin ulcers and necrosis. Secondary local and systemic infection may supervene and, without timely and appropriate interventions, calciphylaxis may be fatal. A precipitant or challenging agent is believed to be necessary to initiate the process. We describe a case of a woman with ESRD receiving continuous ambulatory peritoneal dialysis who developed calciphylaxis in the setting of severe hyperparathyroidism after receiving UV photoradiation therapy. We suggest that the UV light served as the challenging agent in the precipitation of this devastating condition.


Assuntos
Calciofilaxia/diagnóstico , Falência Renal Crônica/diagnóstico , Lúpus Eritematoso Sistêmico/diagnóstico , Nefrite Lúpica/diagnóstico , Terapia Ultravioleta/efeitos adversos , Adulto , Artérias/patologia , Calciofilaxia/patologia , Calciofilaxia/cirurgia , Feminino , Humanos , Hiperparatireoidismo Secundário/diagnóstico , Hiperparatireoidismo Secundário/patologia , Hiperparatireoidismo Secundário/cirurgia , Falência Renal Crônica/patologia , Falência Renal Crônica/cirurgia , Lúpus Eritematoso Sistêmico/patologia , Lúpus Eritematoso Sistêmico/cirurgia , Nefrite Lúpica/patologia , Nefrite Lúpica/cirurgia , Paratireoidectomia , Diálise Peritoneal Ambulatorial Contínua , Pele/irrigação sanguínea
17.
Transplantation ; 67(8): 1162-7, 1999 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-10232568

RESUMO

METHOD: Despite the need to expand the donor pool, it is unclear what parameters should be used. The value of donor renal pathology and calculated creatinine clearance (CrCl) in determining recipient outcome was assessed in 57 kidney transplants from 34 donors in whom pretransplant renal biopsies were performed because of age > or =60, hypertension, and/or vascular disease. We retrospectively compared clinical outcomes in these recipients and 57 control recipients selected to have the same baseline demographics but receiving transplants from low risk donors who were significantly younger (32+/-13.9 vs. 61+/-7.3 years) and lighter weight (71+/-18.1 vs. 84+/-20.2 kg) than the high-risk donors (P<.001 for both). RESULTS: Recipients of high-risk kidneys had a higher incidence of delayed graft function, defined by a <10% fall in serum creatinine (Cr) in the first 24 hr, (56% vs. 30%, P<.01), a higher incidence of rejection (60% vs. 37%, P = .02) and a higher Cr level (197+/-64 vs. 144+/-54 micromol/L at 18 months, P<.005). Graft and patient survival were similar; 12% and 5% vs. 91% and 9% in high-risk vs. control groups, respectively (P = NS). Donor renal pathology was scored 0-3 (none to severe disease) in four areas: glomerulosclerosis, interstitial fibrosis, tubular atrophy, and vascular disease. A donor vessel score of 3/3 was associated with a 100% incidence of delayed graft function and a mean 1-year Cr level of 275+106 micromol/L (compared with 43% and 192+54 micromol/L in those with lower vessel scores, P<.05). Calculated donor CrCl <100 ml/min was associated with higher recipient Cr levels at 1 year, 240+/-95 micromol/L vs. 180+/-54 micromol/L in recipients of kidneys from donors with CrCl levels >100 ml/min (P<.05). The mean 1-year Cr level was 320+/-102 micromol/L in recipients with both a vascular score of 3/3 and a donor CrCl <100 ml/min and 184+/-63 micromol/L in those with neither factor (P = .001). CONCLUSION: Calculated donor CrCl and donor vascular pathology predict recipient graft function and may be helpful in selecting high-risk donors for single kidney transplantation.


Assuntos
Transplante de Rim , Rim/patologia , Rim/fisiopatologia , Doadores de Tecidos , Idoso , Vasos Sanguíneos/patologia , Cadáver , Creatinina/sangue , Feminino , Previsões , Humanos , Nefropatias/sangue , Nefropatias/patologia , Nefropatias/fisiopatologia , Masculino , Pessoa de Meia-Idade , Circulação Renal/fisiologia , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
18.
Biochem Cell Biol ; 76(2-3): 247-56, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9923693

RESUMO

Conformational studies of the salivary peptides histatin 3 (H3) and histatin 5 (H5) were performed by NMR and circular dichroism (CD) in aqueous and nonaqueous solutions. Histatin 5 has no defined structure in H2O but adopts a more helical conformation in dimethyl sulfoxide and aqueous trifluoroethanol. This is in agreement with the CD analysis, which shows no secondary structure in H2O but increasing helical content in the presence of trifluoroethanol. CD analysis shows that H3 has less propensity to form a helical structure than H5 in similar conditions. The NMR analysis of H3 in H2O at pH 7.4 reveals that its conformational mobility is less than that of H5 as indicated by the observation of backbone cross peaks alphaN (i, i + 1) and NN (i, i + 1) and the slow exchanging amide protons in the C-terminus. However, H3 remains essentially unordered as suggested by the lack of longer range nuclear Overhauser effects (NOEs) in the NOESY spectrum. H3 becomes much more ordered in a mixture of 50:50 H2O-dimethyl sulfoxide as indicated by the numerous NOEs, including several side chain to side chain and side chain to backbone connectivities. Our data suggest that in these conditions H3 contains a turn in the region of K13 to K17 and possibly a 3(10) helix at the C-terminus. This study demonstrates that H3 and H5 are both conformationally mobile and that each adopt different types of conformations in aqueous and nonaqueous solutions.


Assuntos
Antibacterianos/química , Antifúngicos/química , Espectroscopia de Ressonância Magnética , Peptídeos , Proteínas/química , Proteínas e Peptídeos Salivares/química , Sequência de Aminoácidos , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Dicroísmo Circular , Histatinas , Humanos , Dados de Sequência Molecular , Estrutura Secundária de Proteína , Proteínas/farmacologia , Proteínas e Peptídeos Salivares/farmacologia , Soluções , Solventes , Relação Estrutura-Atividade , Trifluoretanol , Água
19.
Pediatr Dev Pathol ; 1(1): 49-55, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-10463271

RESUMO

In a previous study, utilizing antibodies to proliferating cell nuclear antigen (PCNA), we determined the proliferation index (PI) (percentage of PCNA-positive cells) of intrinsic renal cell populations in the normal adult and pediatric kidney. We have found that the PI in both adult and pediatric kidneys was very low (below 0.5 in all examined cell populations). In our present study, we investigated cell proliferation in the developing human kidney with an antibody to PCNA. Histologically normal kidneys were collected from 25 fetuses (spontaneous abortions and stillborns) ranging from 10 wk of gestation to term. Immature mesenchyme (blastema), immature early tubules, ampulla of ureteric bud, proximal tubules, Tamm-Horsfall protein (THP)-positive tubules, distal tubules, collecting ducts, and glomeruli were evaluated separately. The PI for each cell population was calculated. The PI of immature early tubules remains high (33-43) throughout embryonic life. The PI of blastemal cells is initially similarly high, but gradually decreases starting from the second trimester. The PI of THP-positive tubules, distal tubules, collecting ducts, and glomeruli starts out relatively high (5.9, 8.6, 6.0, and 12.4, respectively) and decreases gradually as term approaches (1.8, 1.3, 1.2, and 1.4, respectively). Interestingly, as soon as proximal tubules become differentiated (appearance of light microscopic features of proximal tubular epithelium with TP lectin positive brush border), their PI becomes very low (below 1) irrespective of the age of the kidney. This is the first quantitative study to show changes of the PI in various renal cell populations during human nephrogenesis. These changes in the PI relate to the stage of differentiation of the developing nephron segments.


Assuntos
Divisão Celular/fisiologia , Rim/embriologia , Feminino , Humanos , Imuno-Histoquímica , Rim/citologia , Glomérulos Renais/citologia , Túbulos Renais/citologia , Túbulos Renais Coletores/citologia , Lectinas/metabolismo , Mesoderma/citologia , Gravidez , Antígeno Nuclear de Célula em Proliferação/análise
20.
J Pept Res ; 49(6): 596-603, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9266488

RESUMO

A 32 amino acid peptide called histatin-3 (H3; 22% His) and its N-terminal 24 amino acid fragment histatin-5 (H5, 33% His), are found in human saliva and possess powerful antimicrobial properties. These His-rich peptides have been synthesized by Fmoc-based solid-phase chemistry. Their sequences are: DSHAKRHHGYKRKFHEKHHSHRGYRSNYLYDN (H3) and DSHAKRHHGYKRKFHEKHHSHRGY (H5). In addition, we also prepared two H5 and one H3 mutants. The H5 mutants were: DH5 (all amino acids in D configuration) and H5F (where all His are replaced by Phe at positions 3, 7, 8, 15, 18, 19, 21). The 9-24 segment of H3 with all the His at positions 15,18,19,21 replaced by Tyr was also prepared (delta 1-8 H3Y). The behavior of these five peptides was examined with three proprotein convertases (PC's) which possess cleavage specificity directed towards single and pairs of basic residues. These were: human (h)PC1, an endocrine and neural convertase, hfurin and rat (r)PC7, two widely expressed enzymes. All are serine endoproteases belonging to the kexin/subtilisin family. Our in vitro study revealed that H3 behaves as a substrate for PC1, being cleaved by this endoprotease primarily at a site carboxy terminal to the single Arg25 residue (HRGYR decrease SN). On prolonged incubation some minor cleavage was also observed C-terminal to the first LysArg6 pairs of basic amino acids namely at: HAKR decrease HH, which contains a P4 as well as P'1 and P'2 His residues. The second potential site YKRK12-FH which does not have a P4 basic residues is not cleaved, even upon incubation with excess protease. PC1 only poorly cleaves H5 at the same site mentioned above for H3, i.e., at HAKR decrease HH. As expected, neither the D-amino acid analogue (DH5), nor the Phe and Tyr mutant analogues of the long and short histatins, respectively, are cleaved at all. In contrast to the above findings for hPC1, the convertase hfurin did not cleave any of the five synthetic peptides. Instead, H3 and H5 were found to be moderately potent inhibitors of the furin-mediated cleavage of the pentapeptide pGlu-Arg-Thr-Lys-Arg-MCA fluorogenic substrate. This inhibition was reversible and competitive, with an estimated inhibition constant Ki of 1.98 microM for H3 and 2.98 microM for H5. The other analogs exhibited only a moderate to weak inhibition of furin, suggesting that substitution of all His by aromatic residues (Phe or Tyr) drastically reduces their inhibitory potency. When tested against rPC7, H3 exhibited almost identical inhibition profile with a measured Ki of 2.4 microM. The partial sequence identity of H3 to the inhibitory pro-peptide of furin and PC7 provides a rationale for our observation.


Assuntos
Ácido Aspártico Endopeptidases/metabolismo , Inibidores Enzimáticos/farmacologia , Proteínas/farmacologia , Proteínas e Peptídeos Salivares/farmacologia , Subtilisinas/antagonistas & inibidores , Sequência de Aminoácidos , Animais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Furina , Histatinas , Humanos , Cinética , Dados de Sequência Molecular , Pró-Proteína Convertases , Proteínas/química , Proteínas/metabolismo , Ratos , Proteínas e Peptídeos Salivares/química , Proteínas e Peptídeos Salivares/metabolismo , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA