Nisin, an amphiphilic, antimicrobial peptide, has been shown to integrate into the hydrophobic inner region of poly(ethylene oxide) (PEO) brush layers; however, the presence of integrated nisin may compromise the protein repulsive character of the PEO layer. In particular, the introduction of fibrinogen to nisin-loaded brush layers has been observed to cause changes consistent with partial elution of nisin and/or location of fibrinogen at the interface. Questions surrounding the possibility of fibrinogen adsorption warrant further investigation, as the location of procoagulant proteins at a peptide-loaded PEO layer would significantly reduce the viability of a medical device coating based on such an approach. In this work, the preferential location of fibrinogen at PEO brush layers was investigated by: detection of FITC-labeled fibrinogen after sequential introduction of nisin and labeled fibrinogen; measurement of changes in the zeta potential of PEO coated and uncoated surfaces following nisin, fibrinogen, and/or buffer challenges; and evaluation of adsorption and elution kinetics in label-free, sequential adsorption experiments using optical waveguide lightmode spectroscopy (OWLS). PEO layers were constructed through radiolytic grafting of Pluronic�� F108 or F68 onto silanized silica surfaces producing long-chain or short-chain PEO layers, respectively. Adsorption results indicated that sequential introduction of nisin and fibrinogen to PEO brush layers, based on F108, does not result in fibrinogen adsorption beyond that expected for a nisin-free PEO layer. No evidence of nisin entrapment in fibrinogen-repellent F68 layers was recorded. Low-level fibrinogen adsorption observed at F68 layers following the introduction of nisin was determined to be a result of nisin adsorption at (uncoated) defect regions on the surface. In conclusion, retention of PEO layer capacity for protein repulsion after nisin entrapment is owing to a steric repulsive barrier provided by PEO segments extending beyond the level of entrapped nisin. It was then hypothesized that the immobilized, pendant PEO chains will inhibit exchange of entrapped nisin by competing proteins, and therefore prolong nisin activity retention. In order to evaluate nisin function following its entrapment, the antimicrobial activity of nisin-loaded, F108-coated silica surfaces was evaluated against the Gram-positive indicator strain, Pediococcus pentosaceous. The retained biological activity of these nisin-loaded layers was evaluated after incubation in the presence of bovine serum albumin (BSA), for contact periods up to one week. Surfaces were withdrawn at selected times and placed on plates inoculated with P. pentosaceous to measure kill zone radius in order to quantify nisin activity. In the presence of BSA, F108-coated surfaces retained more antimicrobial activity than the uncoated, hydrophobic surfaces. These results strongly suggest that PEO brush layers may serve as a viable drug storage platform due to the retained non-fouling character after bioactive peptide entrapment and the prolonged peptide activity in the presence of other proteins. / Graduation date: 2013

Hemocoagulation, blood coagulation, is an important indicator of hemostatic balance in the human body. There are many ways how to investigate blood clotting. In practice, next to the tests investigating time of coagulation cascade from view of internal way (APTT – activated partial tromboplastin time) and external way (PT – prothrombin time) is often used determining of fibrinogen concentration by Clauss method. Derived fibrinogen method determined fibrinogen concentration, too, by subtracting form the clotting curve in PT test. The reaction for Clauss method is not necessary here. Derived fibrinogen is not used much in practice. This is the reason, why the thesis related to this project will try to find relationship between concentration of fibrinogen and standard tests APTT and PT. Clinical data will be used for this.

No description available.

Despite recent advances in surgical technique and the development of numerous therapeutic agents, the formation post surgical adhesions (PSA) continues to cause complications for many patients. In this research, we have employed a rational system to develop a novel treatment to address this clinical need. Based on an understanding of the biochemical events that lead to PSA formation, a series of targeted polymeric biomaterials was designed to interrupt the fibrin gel matrix propagation and suppress PSA formation. Using group transfer polymerization, a series of well controlled block copolymers of polyacrylic acid and poly(ethylene glycol-methacrylate) based materials was synthesized. Subsequent functionalization with the pentapeptide Cys-Arg-Glu-Lys-Ala (CREKA) was employed to target the materials to fibrin as a marker of pro-adhesive sites. While preliminary testing of the untargeted materials verified their ability to suppress non-specific protein adsorption to model surfaces, numerous in vitro tests were conducted to study the ability to inhibit fibrin gel propagation. The ability to inhibit both the rate and quantity of fibrinogen deposition to a fibrin coated surface has been demonstrated. In addition, the rate of fibrin gel propagation and the degree of cellular attachment can modulated. Taking advantage of the systematic variation in structure facilitated by the robust synthetic methodology employed, statistical analysis was used to elucidate the structureproperty relationships governing the performance of these materials. The most important factors that lead to enhanced performance in in vitro tests are the length of PEG chain and number of peptide units conjugated to the polymer: increasing PEG chain length and increasing the number of peptides conjugated to the polymer both improve performance in all tests. The synthetic methods that have been developed, in conjunction with the experimental results, will be used to direct future studies, including cytotoxicity and animal studies.

The purpose of this study was to construct a flowmeter that could accurately measure the hydraulic permeability of electrospun fibrinogen scaffolds, providing insight into the transport properties of electrospun scaffolds while making the measurement of their topographical features (fiber and pore size) more accurate. Three different concentrations of fibrinogen were used (100, 120, and 150mg/ml) to create scaffolds with three different fiber diameters and pore sizes. The fiber diameters and pore sizes of the electrospun scaffolds were analyzed through scanning electron microscopy and image analysis software. The permeability of each scaffold was measured and used to calculate permeability-based fiber diameters and pore sizes, which were compared to values obtained through image analysis. Permeability measurement revealed scaffold permeability to increase linearly with fibrinogen concentration, much like average fiber diameter and pore size. Comparison between the two measurement methods proved the efficacy of the flowmeter as a way to measure scaffold features.

Orientador: José Paes de Oliveira Filho / Resumo: A Trombastenia de Glanzmann (TG) é uma doença hereditária autossômica recessiva caracterizada por alterações na agregação plaquetária, culminando em sinais clínicos como hemorragias e epistaxe. Duas mutações (c.122G>C e g.1456_1466del) no gene Integrin subunit alpha2β (ITGA2B) foram descritas como responsáveis pela ocorrência da TG em equinos de diversas raças, dentre elas: Quarto de Milha, Puro Sangue Inglês, Standardbred, Oldenburg e Passo Fino. Este gene codifica a subunidade αIIb da integrina αIIbβ3, que é receptora de fibrinogênio nas plaquetas. Embora a TG tenha sido diagnosticada nos EUA, Canadá, Japão e Austrália, estudos de prevalência em equinos no Brasil e no mundo são inexistentes. Objetivou-se determinar a prevalência destas mutações em equinos no Brasil. Utilizou-se 1.053 amostras, oriundas do banco de DNA do LBMCV, de equinos Quarto de Milha (n=679) e Warmblood (n=374) clinicamente saudáveis. Segmentos do DNA foram amplificados por PCR e sequenciados. O genótipo de cada animal foi analisado e comparado à sequência de nucleotídeos do gene ITGA2B depositada no GenBankTM. As mutações responsáveis pela TG não estavam presentes na população estudada. Em outras palavras, todos os animais testados apresentaram genótipo wild type. Sendo assim, nas condições em que este estudo foi realizado, pode-se inferir que, apesar de não ser possível afirmar que não existam cavalos carreadores de alelos mutados para a doença no Brasil, a TG parece ser uma doença extremamente rara n... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Glanzmann thrombasthenia (GT) is an autosomal recessive inherited disorder characterized by changes in platelet aggregation, leading to hemorrhage and epistaxis. Two different mutations (c.122G>C and g.1456_1466del) in the Integrin subunit alpha2β gene (ITGA2B) have been identified in different breeds, i.e., Quarter Horse, Thoroughbred, Standarbred, Oldenburg and Paso Fino. ITGA2B codifies the αIIb subunit of the αIIbβ3 integrin, also termed platelet fibrinogen receptor. Horses with GT have been diagnosed in USA, Canada, Japan and Australia. However, there are no studies on prevalence of GT in equines in the world. The aim of this study was to evaluate the prevalence of the mutations responsible for GT in horses in Brazil. A total of 1,053 DNA samples of clinically healthy Quarter Horse (n = 679) and Warmblood horses (n = 374) were used. DNA fragments were amplified by PCR and sequenced. Subsequently, the genotype of each animal was analyzed and compared to the nucleotide sequence of the ITGA2B gene found on GenBankTM. The mutations involved with GT in horses were not prevalent in the cohort of horses assessed. In other words, all animals tested were wild type. Therefore, under the conditions in which this study was carried out, it can be inferred that, although it is not possible to state the absence of mutated allelles in Brazilian horses, GT seems to be extremely rare in the population of Quarter Horse and Warmblood in Brazil. / Mestre

O fibrinogênio é uma glicoproteína presente no plasma composta por duas subunidades idênticas formadas por três pares de cadeias polipeptídicas (Aα Bβ e ϒ), interligadas por pontes dissulfeto. A trombina cliva o fibrinogênio, liberando os fibrinopeptídeos A e B, formando fibrina e, conseqüentemente, o coágulo. Esse trabalho descreve a purificação e caracterização do fibrinogênio a partir do plasma da serpente Bothrops jararaca (B. jararaca). O fibrinogênio purificado foi obtido através de adsorção com cloreto de bário, precipitações com sulfato de amônio e cromatografia de gel filtração. O fibrinogênio de B. jararaca apresentou massa molecular de 370 kDa em condições não reduzidas e, em condições reduzidas, apresentou massas moleculares de 71, 60 e 55 kDa, similares às cadeias Aα Bβ e ϒ dos fibrinogênio humano e bovino (64, 56 e 47 kDa, respectivamente). Através do seqüenciamento da região amino-terminal das cadeias polipeptídicas por degradação de Edman, foram obtidos os oito primeiros aminoácidos de cada cadeia do fibrinogênio de B. jararaca. As seqüências foram: Gly-Asp-Pro-Glu-Asp-Tyr-Leu-Gly para a cadeia Aα, Gly-Ser-Asp-His-Asp-Asp-Glu para a cadeia Bβ e Glu-Ser-X-Leu-Asp-Glu-Glu-Gly para a cadeia ϒ . As seqüências foram então comparadas com a de outros animais já descritos (NCBI-National Center for Biotechnology Information, www.ncbi.nih.gov), mas devido ao pequeno número de aminoácidos obtidos não foi possível observar similaridades. Através de espectrometria de massa (MALDI-TOF) foram observadas algumas seqüências peptídicas, mas não foi possível obter a seqüência completa do fibrinogênio de B. jararaca. Essas seqüências não apresentaram homologia significante com outras seqüências já descritas. O fibrinogênio de B. jararaca foi coagulado pela trombina bovina enquanto que os venenos das serpentes B. jararaca, Crotalus durissus terrificus e Lachesis muta rhombeata não foram capazes de induzir a formação de coágulo. Além disso, os anticorpos anti-fibrinogênio de B. jararaca produzidos em coelho não reconheceram o fibrinogênio humano. Contudo, os anticorpos anti-fibrinogênio humano reconheceram o fibrinogênio de B. jararaca. Assim, mesmo apresentando similaridades entre os fibrinogênios de B. jararaca e de mamíferos, eles possuem comportamentos distintos, podendo sugerir que a B. jararaca apresenta uma molécula de fibrinogênio diferente do humano para evitar um possível auto-envenenamento. / Fibrinogen is a plasma glycoprotein that is composed of two sets of three nonidentical polypeptide chains (Aα Bβ and ϒ ) which are covalently linked by disulfide bonds. Thrombin cleaves fibrinogen to form fibrin and, consequently, the fibrin clot. This work describes the purification and characterization of fibrinogen from Bothrops jararaca (B. jararaca) snake plasma. Purified fibrinogen was obtained by barium chloride adsorption, ammonium sulfate precipitation and gel filtration chromatography. B. jararaca fibrinogen showed a molecular mass of 370 kDa in non-reducing conditions, similar to human and bovine fibrinogen with 340 kDa. Reduced fibrinogen showed three chains of 71, 60 and 55 kDa, which are similar to the molecular masses of human and bovine Aα Bβ and ϒ fibrinogen chains (64, 56 and 47 kDa, respectively). B. jararaca fibrinogen was clotted by bovine thrombin, however, B. jararaca, Crotalus durissus terrificus and Lachesis muta rhombeata venoms were not able to induce fibrin formation. The N-terminal sequence of B. jararaca fibrinogen chains from PVDF membranes showed only the first eight amino acids residues from each chain. The Nterminal sequence was Gly-Asp-Pro-Glu-Asp-Tyr-Leu-Gly for Aα chain, Gly-Ser-Asp- His-Asp-Asp-Glu for Bβ chain, and Glu-Ser-X-Leu-Asp-Glu-Glu-Gly for ϒ chain. The B. jararaca fibrinogen chains N-terminal sequences were compared to other animal Nterminal sequences previously described. However, due to low signal detection during Edman degradation, the sequence results were not sufficient to provide an accurate Blast search identity (NCBI-National Center for Biotechnology Information, www.ncbi.nih.gov). Mass spectrometry (MALDI-TOF) analysis provides some peptide sequences that did not present the complete sequences. Besides, anti-B. jararaca fibrinogen produced in rabbit did not recognize human fibrinogen while anti-human fibrinogen recognized B. jararaca fibrinogen. Thus, despite B. jararaca fibrinogen presents a molecular mass similar to human fibrinogen, the former shows distinctive features, which protect B. jararaca snakes from a fortuitous ingress of snake venom proteins into snake circulation, which could cause a self-envenomation

Trata-se de um estudo randomizado para avaliação de factibilidade conduzido entre dezembro de 2015 a janeiro de 2017 com pacientes de trauma grave (Index of Shock Severity [ISS] >= 15), admitidos na sala de emergência de um grande centro de trauma. À admissão os pacientes selecionados apresentavam hipofibrinogenemia qualitativa (FIBTEM A5 <= 9 mm) além de hipotensão (pressão arterial sistólica [PAs] < 90mmHg) e taquicardia (frequência cardíaca [FC] > 100 bpm). O desfecho primário foi avaliar factibilidade, definida como a proporção dos pacientes que receberam o tratamento alocado em até 60 minutos após a randomização: reposição de concentrado de fibrinogênio (CF) na dose de 50 mg/kg de peso corporal no grupo intervenção e não receber reposição de fibrinogênio no grupo controle. Uma lista de alocação randomizada dos tratamentos foi gerada por estatístico utilizando \"software\" apropriado. A alocação do tratamento foi realizada utilizando-se envelopes opacos lacrados, numerados sequencialmente. Não houve cegamento por inviabilidade de execução logística. Um total de 84 pacientes foram avaliados para elegibilidade, 52 foram excluídos e 32 foram randomizados, sendo alocados dezesseis em cada grupo. A maioria dos pacientes selecionados foram homens (87,5%), na quarta década de vida (42 ± 15,5) e com ISS de 32 ± 7,2. Todos os pacientes incluídos receberam o tratamento conforme alocado em até 60 minutos após a randomização (100%; IC 95%, 86,7% a 100%). O fibrinogênio sérico na sala operatória (SO) foi maior no grupo intervenção em comparação ao grupo controle (190,4 ± 85,5 vs 130,2 ± 51,1; p=0,04), mas não na chegada à UTI (330,8 ± 165,1 vs 280,3 ± 130,3; p=0,43). Houve diferença estatística significativa no desfecho secundário exploratório tempo médio de internação em UTI entre o grupo experimental e grupo controle (mediana 8, intervalo interquartil [IIQ] 5,75 - 10,0 vs mediana 11, IIQ 8,5 - 16,0; p=0,02). Não houve diferença estatística em qualquer outro desfecho clínico avaliado. Não houve danos ou efeitos indesejáveis. Concluiuse que é possível realizar um estudo clínico randomizado em contexto de emergência com reposição precoce de fibrinogênio através do concentrado de fibrinogênio. O estudo foi registrado no ClinicalTrials.gov (NCT02864875) / This is a randomized feasibility trial conducted between December 2015 and January 2017 with severe trauma patients (Index of Shock Severity [ISS] >= 15) admitted to the emergency room of a large trauma center. At admission patients presented qualitative hypofibrinogenemia (FIBTEM A5 <= 9 mm), hypotension (systolic blood pressure < 90 mmHg) and tachycardia (heart rate > 100 bpm). The primary outcome was feasibility assessed by the proportion of patients receiving the allocated treatment up to 60 minutes after randomization meaning receive replacement through fibrinogen concentrate (50mg per kg of body weight) by the intervention group and not to receive an early replacement of fibrinogen by control group. A randomized allocation list of treatments was generated by a statistician using an appropriate software. The treatment allocation was performed using sealed opaque envelopes, numbered sequentially. There was no blindness because it was no feasible in our institution. A total of 84 patients were assessed for eligibility, 52 were excluded and 32 were randomized (16 allocated to each group). The majority of patients selected were men (87,5%), in the fourth decade of life (42 ± 15,5) with ISS of 32 ± 7,2. All randomized patients received treatment as allocated up to 60 minutes after randomization (100%, 95% CI, 86,7% to 100%). Serum fibrinogen was higher in the intervention group on operating room (OR) (190,4 ± 85,5 vs 130,2 ± 51,1; p=0,04) comparing to control group but this difference was not seen on intensive care unit (ICU) (330,8 ± 165,1 vs 280,3 ± 130,3; p=0,43). The length of ICU stay was smaller in the intervention group compared to the control group (median 8, IQR 5,75 - 10,0 vs median 11, IQR 8,5 - 16,0; p=0,02). There was no difference between groups in any other clinical outcomes. We registered no adverse effects related to treatment in both groups. We concluded that it is possible to perform a randomized clinical trial in an emergency setting with early fibrinogen replacement through the fibrinogen concentrate. The study was enrolled in ClinicalTrials.gov (NCT02864875)

Estudamos a ação das proteases bothropasina e Bothrops protease A, do veneno da serpente Bothrops jararaca, sobre o fibrinogênio (FBG), fibronectina (FN) e cininogênio (HK), como ferramenta para geração de peptídeos bioativos. As sequências primárias dos produtos de digestão foram identificadas por espectrometria de massas, com as buscas direcionadas por peptídeos em comum gerados pelas duas proteases. Foram encontradas oito sequências em comum provenientes do FBG e onze, da FN. Apenas a bothropasina clivou o HK, liberando desArg9BK. Foram sintetizados peptídeos derivados do FBG (FBG1-6) e da FN (FN1-4), além de des-Arg9-BK. Oito peptídeos apresentam potencial atividade antiangiogênica predita in silico. Observamos a inibição da elastase (28-20%) causada por FBG1-2-5-6. A melhor inibição da trombina foi de 17%, por FBG1. Contudo, a maioria dos peptídeos intensificou sua atividade. Por fim, este trabalho sugere que as proteases de veneno de serpentes podem ser usadas como ferramentas para processar componentes do plasma, visando à busca por peptídeos bioativos. / We studied the action of the proteases bothropasin and Bothrops protease A purified from the venom of snake Bothrops jararaca upon fibrinogen (FBG), fibronectin (FN) and kininogen (HK), as a tool to generate bioactive peptides. The primary sequences of the digestion products were identified by mass spectrometry and we focused the search for common peptides released by both proteases simultaneously. Sequences in common released by both proteases were found, being eight peptides from FBG, and 11 from FN. Only bothropasin was able to cleave HK releasing des-Arg9-BK. Peptides from fibrinogen (FBG1-6) and from fibronectin (FN1-4), as well as the des-Arg9-BK were synthetized. Eight peptides have potential antiangiogenic predicted in silico. We observed the inhibition of elastase (28-20%) caused by FBG1-2-5-6. The best inhibition of thrombin was 17% by FBG1. However, most of the peptides intensified its activity. Finally, this work suggests that the snake venom protease can be used as tools to process plasma components in order to search for bioactive peptides.

<p>With the studies performed in this theses the local drug delivery technique FibMat developed by the biotech company AddBIO, was shown to be applicable to other plasma proteins and drugs than the fibrinogen-bisphosphonate combination that is today being commercialized. Hence the potential for a broader field of application was demonstrated. The application targeted today is as a surface modification giving improved strength to bone around screws used in bone implants. The effect of changing protein and manufacturing conditions was studied with null ellipsometry. It was demonstrated that with changes in incubation temperature, pH and salinity the fibrinogen could be successfully exchanged for the plasma proteins human serum albumin and immunoglobulin G. With liquid scintillation counting it was shown that the developed protein multilayers were able to absorb and release the bone strengthening drug alendronic acid in levels comparable to that of the fibrinogen based ditto. Disk susceptibility tests with the bacteria S. Aureus showed a potential for antibacterial functionalization with gentamicin. The release was, in the case of the fibrinogen multilayer, detectable up to 48 hours. Similar test revealed an inability of silver nanoparticle incorporated protein multilayers to achieve inhibitory levels.</p>