Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 213
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Philos Trans A Math Phys Eng Sci ; 377(2137)2018 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-30530541

RESUMO

A short description of the muon tomography demonstrator at the INFN Laboratori Nazionali di Legnaro near Padua, Italy, is given and the principal achievements owing to the data collected at that experimental facility are presented. In particular, the feasibility studies for several applications based on the muon-tomographic technology, within national and European projects, are discussed. The experimental problems and the procedures used to improve the performance are underlined. In addition, new activities and the related detector optimization are illustrated.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.

2.
Braz J Biol ; 82: e268505, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36651460

RESUMO

Several Piper species accumulate piperamides as secondary metabolites, and although they have relevant biological importance, many details of their biosynthetic pathways have not yet been described experimentally. Experiments involving enzymatic reactions and labeled precursor feeding were performed using the species Piper tuberculatum and Piper arboreum. The activities of the phenylalanine ammonia lyase (PAL) enzymes, which are involved in the general phenylpropanoid pathway, were monitored by the conversion of the amino acid L-phenylalanine to cinnamic acid. The activity of the 4-hydroxylase (C4H) enzyme was also observed in P. tuberculatum by converting cinnamic acid to p-coumaric acid. L-[UL-14C]-phenylalanine was fed into the leaves of P. tuberculatum and incorporated into piperine (1), 4,5-dihydropiperine (2), fagaramide (4), trans-piplartine (7), and dihydropiplartine (9). In P. arboreum, it was only incorporated into the piperamide 4,5-dihydropiperiline (3). L-[UL-14C]-lysine was successfully incorporated into the 4,5-dihydropiperine piperidine group (2), dihydropyridinone, and trans- (7) and cis-piplartine (8). These data corroborate the proposal of mixed biosynthetic origin of piperamides with the aromatic moiety originating from cinnamic acid (shikimic acid pathway) and key amide construction with amino acids as precursors.


Assuntos
Lisina , Fenilalanina , Aminoácidos , Fenilalanina/metabolismo , Piper/química
3.
Ann Ig ; 21(6): 555-63, 2009.
Artigo em Italiano | MEDLINE | ID: mdl-20169827

RESUMO

We have analyzed hospitalizations of older people (> 64) from 2002 to 2005. Patients, discharges and stay in hospital have increased, the variation has been statistically significant. We have noticed the same trend about the rehospitalizations. Patients and discharges coming from ASL 5 and zone 4 have decreased in relation with all the elderly people. The reduction of stay in hospital and the decrease of rehospitalizations have been statistically significant.


Assuntos
Hospitalização/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Readmissão do Paciente/estatística & dados numéricos , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Interpretação Estatística de Dados , Hospitais Universitários , Humanos , Itália , Expectativa de Vida , Programas Nacionais de Saúde , Fatores de Tempo
4.
Urology ; 129: 235, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30959118

RESUMO

OBJECTIVE: To show how to perform a robot-assisted partial nephrectomy and bilateral pyelolithotomy in ectopic pelvic kidneys. This is a congenital abnormality of position and rotation1 frequently associated with urolithiasis.2 Renal cell carcinoma is a very rare event in pelvic kidneys.3,4 These 2 findings in the same patient could be a surgical challenge and whenever possible a "one stage" treatment is preferred. MATERIALS AND METHODS: A 44-year-old male with bilateral pelvic kidneys admitted because of left back pain. Abdominal CT scan showed a 17 mm stone in the left renal pelvis, a 12 mm stones in the right pelvis and a 34 × 27 mm right lower pole renal mass. A robotic surgery was indicated. Patient was placed in Trendelenburg position with ports configuration as for transperitoneal radical prostatectomy. The right kidney was firstly approached: after isolation of the ureter and suspension of the renal artery, a clampless partial nephrectomy was performed; then through a longitudinal pyelotomy the stone was extracted. To minimize the opening of the posterior peritoneum covering the left kidney, the site of the stone was identified by intraoperative ultrasound; then, through a longitudinal pyelotomy the stone was extracted. Given the watertight sutures and the lack of ureteral obstructions no pigtails ureteral catheters were inserted. A Jackson-Pratt drainage was placed through the inferior port. RESULTS: Consolle time was 190 minutes. Estimated Blood Loss (EBL) was 50 ml. No complications were reported. The drain was removed on the second postoperative day, assessed that creatinine dosage was equal to serum. The length of stay was 4 days. Histopathology showed a pT1a G2 clear cell renal cell carcinoma with negative surgical margins, while stones analysis was calcium oxalate. CONCLUSION: With the availability of robotic technology, the indications for minimally invasive surgery may be safely expanded to include concomitant morbidities in uncommon presentations.


Assuntos
Pelve Renal/cirurgia , Laparoscopia/métodos , Nefrectomia/métodos , Nefrotomia/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Adulto , Humanos , Pelve Renal/anormalidades , Pelve Renal/diagnóstico por imagem , Masculino , Posicionamento do Paciente , Tomografia Computadorizada por Raios X , Ultrassonografia
5.
Braz J Biol ; 78(1): 117-124, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28699966

RESUMO

Piper tuberculatum (Piperaceae) is a species that accumulates especially amides as secondary metabolites and several biological activities was previously reported. In this article, we report a proteomic study of P. tuberculatum. Bidimensional electrophoresis (2D SDS-PAGE) and mass spectrometry (ESI-Q-TOF) were used in this study. Over a hundred spots and various peptides were identified in this species and the putative functions of these peptides related to defense mechanism as biotic and abiotic stress were assigned. The information presented extend the range of molecular information of P. tuberculatum.


Assuntos
Piper/química , Proteínas de Plantas/análise , Proteoma/análise , Eletroforese em Gel Bidimensional , Piper/metabolismo , Piper/fisiologia , Proteínas de Plantas/química , Proteínas de Plantas/fisiologia , Proteoma/química , Proteoma/fisiologia , Proteômica , Espectrometria de Massas por Ionização por Electrospray
7.
Eur J Surg Oncol ; 43(4): 823-830, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27876194

RESUMO

INTRODUCTION AND OBJECTIVES: To analyze postoperative complications and to assess for significant predictive factors during partial nephrectomy (PN) using a large multicenter dataset. METHODS: Patients who underwent PN for clinical T1 renal tumors at 19 urological Italian centers (Registry of Conservative Renal Surgery [RECORd] project) were evaluated between 2009 and 2012. Anthropometric data, comorbidities and perioperative outcomes were analyzed. Complications were divided as intra- and postoperative, medical and surgical, as appropriate. The severity of postoperative complications was graded according to the modified Clavien classification system. Patients who experienced intraoperative complications were excluded from the analyses for the potential confounding effect in the evaluation of predicting factors for postoperative complications. RESULTS: Overall, 979 patients were analyzed: open, laparoscopic and robot-assisted (available since 2011) surgical approaches were used in 522 (56.4%), 286 (30.9%) and 117 (12.6%) cases, respectively. Surgical postoperative complications were reported in 121 (13.1%) cases (32 (3.5%) were Clavien 3), medical were reported in 52 (5.6%) cases (3 (0.3%) were Clavien 3). No Clavien 4 complications were reported. At multivariable analysis, ECOG score ≥1 (OR 1.98; p = 0.002), lower preoperative hemoglobin (OR 0.71; p < 0.0001) and open surgical approach (2.91; p = 0.02) were significant predictive factors of overall surgical postoperative complications, ECOG score ≥1 (OR 1.93; p = 0.04) and surgical approach (p = 0.05) were significant predictive factors of Clavien 3 either surgical or medical postoperative complications. CONCLUSIONS: Comorbidities and surgical approach should be considered in preoperative evaluation of patients undergoing PN, as they resulted to play a significant role in the occurrence of postoperative complications.


Assuntos
Injúria Renal Aguda/epidemiologia , Carcinoma de Células Renais/cirurgia , Obstrução Intestinal/epidemiologia , Neoplasias Renais/cirurgia , Nefrectomia/métodos , Pneumotórax/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Fístula Urinária/epidemiologia , Idoso , Arritmias Cardíacas/epidemiologia , Transfusão de Sangue , Carcinoma de Células Renais/patologia , Comorbidade , Embolização Terapêutica , Feminino , Hemoglobinas/metabolismo , Hospitais com Alto Volume de Atendimentos , Hospitais com Baixo Volume de Atendimentos , Humanos , Itália/epidemiologia , Neoplasias Renais/patologia , Laparoscopia/métodos , Laparotomia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Isquemia Miocárdica/epidemiologia , Estadiamento de Neoplasias , Pneumonia/epidemiologia , Hemorragia Pós-Operatória/epidemiologia , Hemorragia Pós-Operatória/terapia , Período Pré-Operatório , Estudos Prospectivos , Reoperação , Síndrome do Desconforto Respiratório/epidemiologia , Fatores de Risco , Índice de Gravidade de Doença
8.
Fitoterapia ; 77(3): 243-4, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16567059

RESUMO

Maytenus ilicifolia is an important plant with potential on cancer treatment and has been largely used in Brazil and other countries. We have evaluated the crude ethanolic extract of M. ilicifolia as a potential antioxidant source using an assay based on the bleaching of the radical monocation 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(*+)) and by HOCl scavenger capacity. Trolox and uric acid were used as positive controls. The results indicated M. ilicifolia root bark as a great source of antioxidants based on its potential as scavenger of radicals.


Assuntos
Antioxidantes/química , Sequestradores de Radicais Livres/química , Maytenus/química , Benzotiazóis , Cromanos/farmacologia , Etanol/química , Concentração Inibidora 50 , Casca de Planta/química , Extratos Vegetais/química , Ácidos Sulfônicos/metabolismo , Ácido Úrico/farmacologia
9.
Int J Oral Maxillofac Surg ; 45(2): 135-40, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26655030

RESUMO

Head and neck mucosal melanoma (HNMM) is a rare and aggressive malignancy. The objective of this study was to describe the outcomes of patients with HNMM. Clinical and pathological data from 51 patients with primary HNMM were reviewed. All patients were treated at a single cancer centre between 1954 and 2012. Most tumours involved the nasal cavity (35.3%) and upper gingiva (29.4%). The majority of lesions were ulcerated (54.9%) and pigmented (84.3%). Forty-three patients underwent surgical treatment and 21 (41.2%) underwent adjuvant chemotherapy and/or radiotherapy. Eight patients (15.7%) received palliative treatment. The median follow-up period was 21 months. During this period, 30 (58.8%) patients had tumour recurrences. At the last clinical evaluation, only seven (13.7%) patients were alive with no evidence of disease and three (5.9%) were alive with HNMM. There were significant differences in overall survival probability according to the presence of ulceration (P=0.004), metastatic lymph nodes (P=0.003), and treatment including a radical surgical procedure (P<0.001). On multivariate analysis, ulceration was the only variable associated with an increased risk of death. Despite the poor prognosis, there was significant improvement in overall survival in the most recent years in this sample, mainly due to advances in diagnosis and reconstruction techniques.


Assuntos
Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/terapia , Melanoma/patologia , Melanoma/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Terapia Combinada , Feminino , Neoplasias de Cabeça e Pescoço/mortalidade , Humanos , Metástase Linfática , Masculino , Melanoma/mortalidade , Pessoa de Meia-Idade , Mucosa Bucal/patologia , Mucosa Nasal/patologia , Recidiva Local de Neoplasia/mortalidade , Cuidados Paliativos , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Resultado do Tratamento
10.
Biochim Biophys Acta ; 494(2): 319-25, 1977 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-410451

RESUMO

The bifunctional reagent dimethyl suberimidate, reacting with primary amino groups of proteins, was used to cross-link highly purified human factor VIII. Reaction products were reduced with beta-mercaptoethanol or treated with Rhizopus arrhizus triglyceride lipase. The proportions of the dissociated subunits and their oligomers were calculated from the relative staining intensities of individual bands following polyacrylamide electrophoresis in the presence of sodium dodecyl sulfate. Low concentrations of dimethyl suberimidate (up to 0.5 mM) produced covalently linked dimers which retained full functional (coagulant and von Willebrand factor) activities. Treatment with increasing concentrations of dimethyl suberimidate resulted in an almost simultaneous appearance of both trimeric and tetrameric species, suggesting the existence of specific intra-dimer contacts. A parallel decrease of functional activities was observed at higher concentrations of dimethyl suberimidate. A monofunctional reagent (ethyl acetimidate), reacting similarly with primary amino groups, amidinated factor VIII at rates similar to dimethyl suberimidate. Up to 40% amidinated factor VIII retained full biological activities. We conclude that the most reactive lysine residues are not involved in the active sites responsible for either coagulant or von Willebrand activity.


Assuntos
Fator VIII , Coagulação Sanguínea , Fenômenos Químicos , Química , Dimetil Suberimidato , Ácido Edético , Eletroforese em Gel de Poliacrilamida , Fator VIII/metabolismo , Humanos , Imidas , Lipase/metabolismo , Lisina , Mercaptoetanol , Peso Molecular , Conformação Proteica , Relação Estrutura-Atividade , Fator de von Willebrand/fisiologia
11.
Biochim Biophys Acta ; 400(1): 112-20, 1975 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-125108

RESUMO

A method is presented for detection of cross-linking acceptor sites on fibrinogen chains, using monodansyl-cadaverine labeling in the presence of activated fibrin stabilizing factor, and polyacrylamide electrophoresis in the presence of sodium dodecyl sulfate. Fluorescent gamma-chain monomers and dimers were produced at a considerably faster rate than the labeled alpha-chain derivative. Purified fragments X, Y and D were prepared all from the same plasmic digest of fibrinogen. Following incubation with fibrin stabilizing factor, thrombin and monodansyl-cadaverine, they were reduced with beta-mercaptoethanol and examined by sodium dodecyl sulfate/acrylamide electrophoresis. Three gamma-chains (mol. wts 49 000, 42 000 and 39 000) had reacted with dansyl-cadaverine while no alpha-chain remnant took up the label. Additional protein and carbohydrate staining further facilitated identification of the individual subunit chains. At least three critical peptide bonds, located on alpha, beta- and gamma-chain remnants, must be broken during conversion of fragment Y into D and E. Sequential cleavage results in heterogeneous appearance of reduced subunit chains. As a consequence, there exist several molecular entities of fragment Y, all of which may have the same molecular weight though they represent various products of progressive plasmic digestion. Our results are compatible with the model of asymmetric degradation of fibrinogen, according to which fragment X produces 1 mol of fragment E e and 2 mol of the monomeric fragment D.


Assuntos
Fibrinogênio , Fibrinolisina , Sequência de Aminoácidos , Aminoácidos/análise , Sítios de Ligação , Cromatografia em Gel , Eletroforese em Gel de Poliacrilamida , Humanos , Peso Molecular , Fragmentos de Peptídeos/análise , Ligação Proteica , Conformação Proteica , Estreptoquinase
12.
Biochim Biophys Acta ; 400(1): 95-111, 1975 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-125109

RESUMO

A mixture of fragments D, derived from fibrinogen by plasmic degradation, was S-reduced and carboxymethylated. Individual chains were separated by gel filtration on Sephadex G-100 and characterized by peptide mapping, N-terminal amino acid analysis, polyacrylamide electrophoresis in sodium dodecyl sulfate, and amino acid composition. It was demonstrated that all D species contain the same alpha- and beta-chain remnants, having mol. wts of 10 000 and 45 000, respectively. Their heterogeneity was shown to be caused by the gradual degradation of the gamma-chain at its C-terminal end. Denatured fragment D was further degraded with plasmin in the presence of 2 M urea. One beta- (mol. wt 17 000) and two gamma-fragments (mol. wts 5000 and 6000) were split from fragment D, in addition to non-characterized small peptides, leaving behind a plasmin-resistant core, designated as fragment d. Fragment d was in turn reduced and carboxymethylated, and the resulting constituent chains were isolated by chromatography on carboxymethyl-cellulose and Sephadex G-100. The reduced alpha-, beta- and gamma-chain remnants of fragment d were found to have been derived from the N-terminal portion of fragment D and have estimated mol. wts of 9000, 24 000 and 13 000, respectively. A tentative scheme for the conversion of an early fragment D into the core fragment d is proposed. Our results conclusively support the model of asymmetric degradation of fibrinogen, according to which 2 mol of monomeric fragment D are produced from 1 mol of fibrinogen.


Assuntos
Fibrinogênio , Fibrinolisina , Sequência de Aminoácidos , Aminoácidos/análise , Sítios de Ligação , Cromatografia em Gel , Cromatografia em Camada Fina , Dissulfetos/análise , Fibrinogênio/metabolismo , Humanos , Peso Molecular , Oxirredução , Fragmentos de Peptídeos/análise , Ligação Proteica , Conformação Proteica , Desnaturação Proteica , Ureia
13.
Biochim Biophys Acta ; 742(1): 25-32, 1983 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-6824684

RESUMO

Fibrinopeptides A and B were removed from purified human fibrinogen by bovine thrombin, whereas the snake venom protease batroxobin only split fibrinopeptide A from fibrinogen. Aggregation of the resulting desAB- and desA-fibrin monomers was evaluated by recording the turbidity of incubation mixtures. Fibrin assembly was strongly accelerated by increasing the calcium concentration from 10(-5) to 10(-3) M. Fragment D was obtained from fibrinogen by proteolytic degradation with plasmin in the presence of Ca2+. At a 4-fold molar concentration relative to fibrinogen, fragment D dramatically inhibited fibrin polymerization at up to 10(-4) M Ca2+. This anticlotting activity was, however, much less pronounced at 10(-3) M Ca2+. The thrombin clotting time, measured on human plasma, was prolonged by fragment D in a dose-dependent manner. In citrate-containing plasma, the fibrinogen clotting was significantly delayed by an equimolar concentration of fragment D. In barium sulfate-adsorbed oxalated plasma, containing 2.5 mM Ca2+, the same amount of fragment D hardly affected fibrin polymerization. We conclude that fragment D has no important anticlotting effect under physiological conditions. The synthetic peptide Gly-Pro-Arg, corresponding to the amino-terminal sequence of the fibrin alpha-chain, inhibited aggregation of both desA-fibrin and desAB-fibrin at 10(-3) M Ca2+. The inhibition of desAB-fibrin polymerization by Gly-Pro-Arg was abolished at 10(-5) M Ca2+. In addition, Gly-Pro-Arg depressed the anticlotting activity of fragment D at low calcium concentration. An analogue of the amino-terminus of fibrin beta-chain, Gly-His-Arg, strongly accelerated aggregation of desA-fibrin monomers, but only moderately enhanced polymerization of desAB-fibrin monomers at 10(-5) M Ca2+, both in the presence and in the absence of fragment D. This activating effect of Gly-His-Arg was abolished at 10(-3) M Ca2+. It is suggested that the binding of calcium, Gly-His-Arg, and possibly also Gly-Pro-Arg, induces a conformational change in fibrin monomers and thus accelerates the polymerization process.


Assuntos
Cálcio/farmacologia , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Fibrina/metabolismo , Oligopeptídeos/farmacologia , Animais , Coagulação Sanguínea , Bovinos , Fibrinogênio/metabolismo , Fibrinopeptídeo A/isolamento & purificação , Fibrinopeptídeo B/isolamento & purificação , Humanos , Cinética , Substâncias Macromoleculares
14.
Biochim Biophys Acta ; 623(2): 402-11, 1980 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-6772231

RESUMO

Factor VIII of human cryoprecipitate was purified and fractionated on Sepharose CL-2B into three fractions of progressively decreasing multimer size and ristocetin cofactor activity. Following complete disulfide reduction, the resulting subunits were electrophoresed on 3% polyacrylamide gels and subsequently stained with two galactose-specific, fluorescein-labelled lectins from Ricinus communis (RCAI and RCAII). Measurements of fluorescence indicated that the reduced chains, derived from the largest factor VIII multimers, have stronger binding affinity for both lectins than those obtained after reduction of smaller factor VIII species. Ristocetin cofactor activity of purified factor VIII was competitively inhibited by both Ricinus lectins and by concanavalin A. RCAI-lectin was found to be a considerably more efficient inhibitor than RCAII or concanavalin A. Following removal of sialic acid from factor VIII, the inhibiting effect of RCAII-lectin was markedly potentiated, probably by exposing additional galactose residues, some of which must be located close to the ristocetin cofactor 'active site' of factor VIII. Ristocetin cofactor activity was also strongly inhibited with RCAII-lectin for binding sites which are located on the surface factor VIII multimers. Our results suggest that RCAI-lectin, which contains galactose-specific binding sites per molecule, and anti-factor VIII antibodies inhibit ristocetin cofactor activity by crosslinking and aggregation of factor VIII multimers.


Assuntos
Fatores de Coagulação Sanguínea , Fator VIII , Galactose , Lectinas , Fator de von Willebrand , Anticorpos , Carboidratos/farmacologia , Fator VIII/fisiologia , Humanos , Neuraminidase , Agregação Plaquetária/efeitos dos fármacos , Ligação Proteica
15.
Biochim Biophys Acta ; 578(1): 164-74, 1979 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-454664

RESUMO

Human factor VIII-related protein was isolated from cryoprecipitate by agarose (Sepharose CL-2B) gel filtration. Electrophoresis on SDS-2% polyacrylamide-0.5% agarose gels revealed size heterogeneity of factor VIII-related protein which was similar to that shown by SDS-1% agarose gel electrophoresis and electron microscopy. The apparent molecular weights were compared with those of crosslinked IgM oligomers and corresponded to values of up to 20 . 10(6) for factor VIII eluting close to the void volume of our gel filtration column. Measurement of mobility intervals on electrophoretic gels suggested a constant size difference between adjacent bands. Smaller aggregates were found in later eluates from Sepharose columns as well as following partial reduction of factor VIII with cysteine. In order to compare the size difference between small and large aggregates of factor VIII-related protein we calibrated the SDS-2% polyacrylamide-0.5% agarose gels with factor VIII which had been crosslinked with dimethyl suberimidate and subsequently disulfied-reduced with 2-metcaptoethanol. By combination of calibration ranges, constant intervals were measured for large and smaller factor VIII aggregates. The interval between any neighboring protein bands, which were immunologically identified as factor VIII-related protein, was equal to the dimer of the basic factor VIII subunit chain. We conclude that factor VIII aggregates correspond to multimers of a dimeric molecule, i.e. pairs of the basic subunit chain.


Assuntos
Fator VIII , Cromatografia em Gel , Cisteína , Eletroforese em Gel de Ágar , Eletroforese em Gel de Poliacrilamida , Glicoproteínas/sangue , Humanos , Substâncias Macromoleculares , Peso Molecular , Ligação Proteica
16.
Biochim Biophys Acta ; 579(2): 325-33, 1979 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-534647

RESUMO

Human and bovine factor VIII were isolated from cryoprecipitate of fresh frozen plasma by gel filtration on Sepharose CL-2B. The elution diagrams and SDS-agarose electrophoretic analysis of eluted fractions show no significant differences in the size-distribution of factor VIII aggregates between the two species. Agarose gels were stained for carbohydrate by two methods: (1) the dansyl hydrazine reaction following oxidation with periodic acid and (2) staining with fluorescein-labeled concanavalin A. Results of both procedures indicate that in human factor VIII neither the size distribution nor its ristocetin cofactor activity are related to carbohydrate content. Bovine factor VIII contains slightly less sugar than the human preparation as judged from the relative dansyl hydrazine staining intensities. In contrast to human factor VIII, the binding affinity for concanavalin A of bovine factor VIII was gradually decreased with increasing aggregate size. This finding suggests an impaired accessibility of reactive sugar residues in large aggregates of bovine factor VIII.


Assuntos
Carboidratos/análise , Fator VIII/isolamento & purificação , Animais , Bovinos , Fenômenos Químicos , Química , Humanos , Agregação Plaquetária , Especificidade da Espécie
17.
Biochim Biophys Acta ; 924(1): 27-37, 1987 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-3493809

RESUMO

Von Willebrand factor molecules are flexible linear polymers composed of repeating protomeric polypeptide subunits. In the process of primary hemostasis, von Willebrand factor promotes platelet adhesion and platelet plug formation at the site of vascular injury. This biologic activity is apparently related to the multimeric size of von Willebrand factor. We simulated von Willebrand factor binding to the subendothelial surface by adsorbing purified human von Willebrand factor onto polystyrene latex particles of two different diameters, i.e., 0.312 micron and 2.02 micron. The rate and extent of 125I-labeled von Willebrand factor binding to polystyrene was similar with both size classes of latex particles. The von Willebrand factor-coated latex beads of 2.02 micron diameter, in contrast to the smaller size, induced rapid agglutination of formalin-fixed human platelets in the absence of any other aggregating agent. Von Willebrand factor was also adsorbed from human plasma onto latex particles coated with anti-von Willebrand factor antibodies. Again, only the large beads, carrying the von Willebrand factor-antibody complex, induced agglutination of fixed platelets. Shear stress promoted the rate of von Willebrand factor adsorption to latex particles. Our results suggest that adsorption to surface exposes binding sites in human von Willebrand factor for platelets.


Assuntos
Plaquetas/metabolismo , Fator de von Willebrand/metabolismo , Adsorção , Humanos , Cinética , Látex , Poliestirenos , Estresse Mecânico , Fator de von Willebrand/isolamento & purificação
18.
Biochim Biophys Acta ; 669(1): 98-104, 1981 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-6794637

RESUMO

We have designed an electrophoretic system for the fractionation of individual, biologically active multimers of factor VIII. Human factor VIII, purified by gel filtration on Sepharose CL-2B from plasma cryoprecipitate, was submitted to electrophoresis without SDS on 2.0% polyacrylamide gels in 0.04 M Tris/0.06 M Tes buffer, pH 7.5. Staining with Coomassie blue revealed a series of protein bands. Measurement of electrophoretic mobility showed constant size intervals between adjacent bands. Electrophoresis in a second dimension, in the presence of SDS, resulted in an identical order of mobilities, suggesting that the different migration rates of factor VIII proteins in the first electrophoretic system were size- and not charge-dependent. After electrophoresis in the absence of SDS both factor VIII coagulant and ristocetin cofactor activities as well as factor VIII-related antigen were recovered by elution from gel slices. The distribution of activity peaks resembled that of Coomassie-stained factor VIII proteins found in control gels. We thus demonstrate that an electrophoretic fractionation of factor VIII multimers is possible even at neutral pH where factor VIII activities are retained.


Assuntos
Fator VIII/isolamento & purificação , Antígenos/isolamento & purificação , Cromatografia em Gel , Eletroforese em Gel de Poliacrilamida , Fator VIII/imunologia , Humanos , Peso Molecular , Dodecilsulfato de Sódio
19.
Biochim Biophys Acta ; 578(1): 155-63, 1979 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-313218

RESUMO

Human factor VIII-related protein precipitates with specific heterologous anti-bodies directed against purified factor VIII and supports ristocetin-induced aggregation of washed platelets. We purified human factor VIII from cryoprecipitate by subsequent gel filtration on crosslinked large-pore agarose. Factor VIII-related protein appeared as a large aggregate following electrophoresis on 3% polyacrylamide gels in the presence of sodium dodecyl sulfate (SDS). The same material was separated into multiple bands (molecular weight in excess of several millions) following electrophoresis on SDS-1% agarose gels. After complete disulfide reduction of factor VIII-related protein and electrophoresis on SDS-5% polyacrylamide gels a single subunit chain (Mr approximately equal to 200 000) was revealed. Analysis of this protein, in its non-reduced state, by negative contrast electron microscopy showed filaments of markedly variable size. The calculated molecular weight of such filaments ranged from about 0.6.10(6) to 20.10(6). We conclude that size heterogeneity is an essential feature of human factor VIII-related protein.


Assuntos
Fator VIII , Glicoproteínas/sangue , Dissulfetos , Eletroforese , Humanos , Substâncias Macromoleculares , Microscopia Eletrônica , Peso Molecular , Oxirredução , Ligação Proteica , Fator de von Willebrand
20.
Braz J Biol ; 75(3): 692-702, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26465730

RESUMO

The life cycle of the crab Callinectes danae is estuarine-dependent, and studies on aspects of their biology should also cover marine areas. The present study investigated the sexual maturity, as well as habitat preference by adults in different gonadal stages, and the crabs' reproductive periodicity outside the estuary. Three bays on the subtropical southeastern coast of Brazil were sampled monthly for two years. For each bay, six transects were established, four of them parallel to the beach line (5, 10, 15 and 20 m depth), as well as one transect in an exposed area, and another sheltered from the action of waves. The results showed that the pattern of spatio-temporal distribution of adults C. danae was similar in three bays, although the highest abundance was found in Ubatumirim. Females with developed gonads/ovigerous females were found in greater abundance than females with rudimentary/developing gonads, mainly in deeper transects. Although the areas sampled have different environmental characteristics, the reproductive pattern of the species did not change, showing continuous reproduction throughout, with more abundance of reproductive females on spring and summer. Males reached maturity at larger sizes than females in all three bays.


Assuntos
Braquiúros/fisiologia , Animais , Braquiúros/crescimento & desenvolvimento , Brasil , Feminino , Masculino , Reprodução , Estações do Ano , Maturidade Sexual
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA