Post surgical adhesions (PSAs) are an inevitable outcome of surgery and their presence leads to pathogeneses and significant economic impact. The studies within this thesis utilised standard and reproducible abrasion models, in rabbits, pigs and rats, to investigate the formation and maturation of PSAs with strict quantitative analyses. These studies have shown that the development of PSAs is a series of complex, multi-factorial processes. PSA development can be classified into two stages: (i) PSA modelling occurring up to/including 16 hours post injury characterised by the inflammatory response and fibrin deposition and maturation; and (ii) PSA remodelling occurring from 16 hours onwards and characterised by tissue repair, collagen deposition and maturation and chemical mediation by TGF-P. Treatment with VivostatTM System Derived (novel) Fibrin Sealant significantly reduced the formation of PSAs with mean PSA reduction of 80% for the rabbit uterine horn abrasion model, from 3 separate studies; 83% for the pig stomach/colon/caecum abrasion model, from 2 separate studies; 80% for the rat caecum abrasion model. This is significantly better than other fibrin sealants investigated in this thesis. PSA prevention with novel fibrin sealant demonstrated a similar pattern to PSA development, with two stages of development evident: (i) tissue generation modelling occurring up to/including 16 hours post injury characterised by the inflammatory response and fibrin deposition and maturation; and (ii) tissue generation remodelling occurring from 16 hours onwards and characterised by tissue repair, collagen deposition and maturation and chemical mediation by TGF-P. However the extent and subsequent time taken for these changes to occur was significantly reduced. The prevention of PSAs and alterations of wound healing by novel fibrin sealant is most probably due to the sealant acting as a haemostat, as well as a physical barrier. Thus preventing fibrinous and subsequent fibrous PSA formation.

A durotomia acidental, na cirurgia da coluna lombar, é uma das mais comuns complicações, com uma prevalência de 1 a 17%. As fraturas da coluna também podem apresentar-se com lesão dural, chegando a 19% nas fraturas tipo explosão da coluna torácica ou lombar com lesão associada da lâmina vertebral. Procurou-se avaliar as alterações medulares que ocorreram apos a reparação de lesão dural com pontos do tipo simples, com cola de fibrina e com colágeno bovino, através de análise histológica. Manteve-se um grupo controle, sem reparação. Utilizaram-se 70 ratos da raça Wistar, sendo que 34 foram excluídos por problemas anestésicos ou intra-operatórios. Mantiveram-se nove ratos por grupo. Abordaram-se os segmentos vertebrais T8 e T9, para efetuar a lesão, que foi reparada pelos três diferentes métodos avaliados. Os animais permaneceram confinados por 24 dias, sendo submetidos à eutanásia com a coleta de material para análise histológica. O Serviço de Patologia avaliou e graduou (ausente, discreto, moderado e acentuado) os casos quanto à hiperemia, degeneração medular, necrose e infiltrado celular. De forma geral, as técnicas de reparo apresentaram resultados com maior grau de alteração, principalmente em relação ao infiltrado celular, onde todas as técnicas mostraram resultados bem piores. A sutura apresentou graus mais severos de necrose, hiperemia e infiltrado celular. A membrana de colágeno apresentou resultados com graus mais elevados de alteração em relação à hiperemia, à degeneração da substância nervosa e ao infiltrado celular. A reparação com cola de fibrina apresentou piora em relação ao grau de necrose e de infiltrado celular. A presença de alterações medulares em todos os grupos, até mesmo no grupo controle, levou a cogitar algumas possíveis causas para os resultados: as alterações medulares seriam geradas pela técnica cirúrgica ocorrendo uma lesão iatrogênica medular, mas sem repercussão clinica; os materiais estudados poderiam causar alterações no tecido neural; o simples contato do tecido neural com o meio extra-dural, após a lesão, seria a causa das alterações levando à mesma cascata de alterações que ocorre nas lesões medulares traumáticas. Apesar de todos os grupos apresentarem alterações medulares, ficou evidente que as de maior intensidade ocorreram nos grupos que utilizaram materiais de fechamento dural. Os métodos de reparação dural ainda não são os ideais, mas existe o consenso que a lesão deve ser reparada sempre na forma aguda, a fim de evitar e prevenir complicações e seqüelas. / This study aimed to evaluate spinal cord alterations after dural repair with: simple interrupted suture, collagen membrane or fibrin glue using histopathogical analysis. All activities were performed in the São Paulo University Medical School General Hospital Traumatology and Orthopedic Division. Seventy Wistar rats were used, but 34 were excluded due to anesthetic or surgery problems. Animals were kept isolated for 24 days, then killed and histological samples collected. Pathology Division assessed and graduated hyperemia, spinal cord degeneration, necrosis and cellular infiltration. Repair techniques provided higher alteration, mostly in cellular infiltration. Suture showed more severe necrosis, hyperemia and cellular infiltrates graduations. Collagen membrane provided higher alterations related to hyperemia, nerve degeneration and cellular infiltrates. Fibrin glue reparation had worse results in necrosis and cellular infiltrates graduation.Spine cord alterations in all groups, including control group, made us suppose possible reasons for the results: spine cord changes would be caused by surgical technique as iatrogenic injury, without clinical meaning; studied material would cause alterations in neural tissue; contact of neural tissue with extra dural environment, after injury, leading to the same mechanisms present in spinal cord traumatic injury. Despite all groups showed spinal cord alterations it was clear a higher intensity of injury when dural closing material were used. There is no ideal choice for dural repair material and more research is warranted to find better form of repairing dura mater.

Background: Glycation influences the ultrastructure and clot kinetics of fibrin clots due to the post-translational modifications in fibrinogen. Methylglyoxal (MG) is used to measure the level of glycation which has been associated with the pathogenesis of type 2 diabetes Melilites (T2DM) and coronary heart disease (CHD). The aim of the study was to determine the role of MG on clot kinetics and fibrin clot structure in CHD patients with and without T2DM to provide insight into the mechanism of pathogenesis of atherosclerosis in T2DM which results in the development of CHD. Methodology: Scanning electron microscopy (SEM) was used to evaluate the morphology of fibrin clots. Thromboelastography (TEG) was used to assess the physiological clot properties (kinetics). Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of methylglyoxal-adducts. Results: The morphology of clots from controls analysed using SEM showed thick and thin fibres which created an organised mesh of fibrin fibres. In T2DM, CHD with T2DM and CHD some alterations in the morphology were observed. The ultrastructure micrographs in CHD shows that some of the fibrin fibres formed have individual fibres with both thick and thin fibres as well as a thick mass of fibres with a net-like structure that forms dense-matted deposits. In addition, the fibrin fibres are not organised. The densitometry analysis between controls and patient groups’ (CHD: mean (standard deviation) 0.42±0.11; CHD+T2DM: 0.31±0.08 and T2DM: 0.29±0.08) was found to be significantly lower in all groups compared to the control which had a mean of 0.57±0.1, p<0.0001. There are no significant differences in the alpha angle between CHD, T2DM, CHD with T2DM and controls (60.88±2.321˚ vs. 60.81±2.385˚ vs. 59.09± 3.185˚ vs. 66.47±1.300˚, p=0.5279). There was no significant difference found in the K-value between T2DM, CHD with T2DM, CHD and control subjects (3.458±0.446mins vs. 5.118±1.589mins vs. 3.758±0.450mins vs. 2.839±0.2156mins, p=0.0102). The maximum amplitude was higher in T2DM patients compared to CHD, CHD with T2DM and controls (40.51±1.914mm vs. 34.10±2.127mm vs. 33.12±3.365mm vs. 33.60±1.525mm, p=0.0102). The MRTG was higher in CHD compared to T2DM, CHD 4 with T2DM and controls (10.74±3.335 dyn cm-2 s -1 vs. 4.268±0.690 dyn cm-2 s -1 vs. 5.046± 0.927 dyn cm-2 s -1 vs. 6.535±0.664 dyn cm-2 s -1 , p=0.0096). The reaction time was higher in CHD with T2DM patients compared to T2DM, CHD and controls (32.58±4.005min vs. 23.92±2.793min vs. 21.29± 2.383min vs. 8.322±0.886min, p<0.0001). There was no significant difference found in the TTG between T2DM, CHD with T2DM, CHD and control subjects (231.3±28.68 dyn cm-2 vs. 258.5±38.15 dyn cm2 vs. 343.7±71.92 dyn cm-2 vs. 287.7±21.37 dyn cm-2 , p=0.8421). The TMRTG was higher in T2DM patients compared to T2DM, CHD with T2DM, CHD and controls (23.91±2.409mins vs. 20.46±3.411mins vs. 14.14±1.287mins vs. 10.16±0.751mins, p<0.0001). To assess if an association between MG-adducts and clot kinetics exists, the Spearman r correlation was completed for each clot parameter. The reaction time (p=0.0047, 95% CI: 0.138 to 0.665) and time taken before maximum speed of the clot growth to be achieved (p=0.3958, 95% CI: 0.072 to 0.644) was significant. This indicates the relationship between the parameters i.e., the higher the level of MGadducts present, the longer it takes for clotting to begin and reach maximum speed of formation. Conclusion: This study showed that there are ultrastructural differences in fibrin fibres formed in CHD patients with T2DM. The viscoelastic parameters indicated that haemostasis was irregular in CHD and T2DM. The levels of MG-adducts were much higher in T2DM, CHD with T2DM and CHD and may be a contributing factor to the pathogenesis associated with altered coagulation in these patients. / Dissertation (MSc (Physiology))--University of Pretoria, 2020. / NRF / Physiology / MSc (Physiology) / Unrestricted

Orientador: Daniela Leal Zandim-Barcelos / Resumo: A fibrina rica em plaquetas e leucócitos (L-PRF) é um derivado plaquetário autógeno capaz de liberar citocinas e fatores de crescimento favoráveis ao reparo tecidual. Por esta razão a L-PRF vem sendo utilizada em diversos procedimentos odontológicos. Uma das aplicabilidades clínicas da L-PRF é em procedimentos de levantamento do seio maxilar, uma técnica já consagrada na odontologia que permite a colocação de implantes dentários em região posterior de maxilas atróficas. Para avaliar a efetividade do uso da L-PRF, dois estudos clínicos independentes foram realizados utilizando a L-PRF em seios maxilares. Um deles teve o propósito de avaliar a influência da L-PRF na regeneração óssea quando associada ao osso mineral bovino desproteinizado (OBD) em procedimentos de elevação do assoalho do seio maxilar, e o outro teve o propósito de avaliar a efetividade da L-PRF no reparo de membranas de Schneider acidentalmente perfuradas durante o procedimento de levantamento do seio maxilar. Para isso, o primeiro trabalho foi um estudo clínico randomizado controlado envolvendo 19 pacientes com edentulismo na região posterior de maxila. De forma aleatória, 24 seios maxilares destes 19 pacientes foram distribuídos entre os grupos teste e controle. O grupo teste abordou 12 seios maxilares que foram enxertados com OBD associado à L-PRF, já o grupo controle abordou outros 12 seios maxilares enxertados apenas com OBD. Após 8 meses de reparo, uma biópsia foi obtida por meio de broca trefina no mesmo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Platelet and leukocyte-rich fibrin (L-PRF) is an autogenous platelet derivative capable of releasing cytokines and growth factors favorable to tissue repair. For this reason, LPRF has been used in several dental procedures. One of the clinical applicabilities of L-PRF is in maxillary sinus lifting procedures, a technique already established in dentistry that allows the placement of dental implants in the posterior region of atrophic jaws. To assess the effectiveness of using L-PRF, two independent clinical studies were conducted using L-PRF in maxillary sinuses. One of them had the purpose of evaluating the influence of L-PRF in bone regeneration when associated with deproteinized bovine mineral bone (DBB) in maxillary sinus floor elevation procedures, and the other had the purpose of evaluating the effectiveness of L-PRF in the repair of Schneider membranes accidentally perforated during the maxillary sinus lifting procedure. For this, the first study was a randomized controlled clinical study involving 19 patients with edentulism in the posterior region of the maxilla. At random, 24 maxillary sinuses of these 19 patients were distributed between the test and control groups. The test group involved 12 maxillary sinuses that were grafted with DBB associated with L-PRF, whereas the control group addressed 12 other maxillary sinuses grafted only with DBB. After 8 months of repair, a biopsy was obtained using a drill bit on the same axis of insertion of the implants. The biopsie... (Complete abstract click electronic access below) / Mestre

Cardiovascular disease is the leading cause of death in the US, which can result in blockage of a coronary artery, triggering a myocardial infarction (MI). After a MI, hypoxic ventricular myocardial tissue dies, resulting in the deposition of non-contractile scar tissue and remodeling of the ventricle, leading to decreased cardiac output and ultimately heart failure. Currently, the gold-standard solution for total heart failure is a heart transplant. As donor hearts are in short supply, an alternative to total-organ transplantation is surgically remodeling the ventricle with the implantation of a cardiac patch. Acellular cardiac patches have previously been investigated using synthetic or decellularized native materials in effort to improve cardiac function. However, a limitation of this strategy is that acellular cardiac patches only reshape the ventricle and do not increase cardiac contractile function. By incorporating the use of a clinically relevant cell type and by matching native architecture, we propose the use of a highly aligned fibrin scaffold to support the maturation of human induced pluripotent stem cell cardiomyocytes (hiPS-CM) for use as a cell-populated cardiac patch. By micropatterning fibrin hydrogels, hiPS-CM seeded on the surface of this scaffold become highly aligned, which is crucial for increased contractile output. Our lab previously developed a composite fibrin hydrogel and microthread cardiac patch matching mechanical properties of native myocardium. By micropatterning fibrin hydrogel alone, we were able to match cellular alignment of hiPS-CM to that of native myocardium. hiPS-CMs seeded on this surface were found to express distinct sarcomere alignment and circumferential connexin-43 staining at 14 days of culture as well as cellular elongation, which are necessary for mature contractile properties. Constructs were also cultured under electrical stimulation to promote increased contractile properties. After 7 days of stimulation, contractile strains of micropatterned constructs were significantly higher than unpatterned controls. These results suggest that the use of topographical cues on fibrin scaffolds may be a promising strategy for creating engineered myocardial tissue to repair damaged myocardium.

Fibrinogen concentrates are used widely as a sealant during and after surgery to reduce blood loss. Commercially available fibrin sealants are made from pooled human blood, which carries the risk of blood-borne diseases, and are expensive. These concerns have brought to focus the need for autologous fibrinogen concentrates. This need has been addressed by utilizing a unique approach in which fibrinogen is precipitated from plasma with protamine. The physical properties of fibrin sealant prepared from fibrinogen precipitated with protamine were evaluated. The optimal precipitation conditions included a plasma protamine concentration of 10 mg/mL at room temperature. Under these conditions 96% ± 4% of the fibrinogen present in the plasma was precipitated and 98% ± 0.9% of the precipitated fibrinogen was clottable. In addition, it was shown that almost 50% of the factor XIII in the plasma was also precipitated along with the fibrinogen. The tensile and adhesion strengths and kinetics of fibrin sealant prepared from protamine-fibrinogen concentrate were evaluated. Tensile strength and adhesion strength both increased with increasing fibrinogen concentration. Addition of calcium chloride significantly increased the tensile and adhesion strengths. The addition of aprotinin and ε-aminocaproic acid (used to inhibit natural fibrinolysis) to the fibrinogen concentrate was shown to have no effect on the mechanical properties of the sealant. Kinetic experiments showed that the clotting time decreased as the thrombin and fibrinogen concentrations were increased. A rat model with controlled renal incisions was employed to evaluate the hemostatic efficacy of the fibrin sealant made from the protamine-fibrinogen concentrate. The fibrin sealant significantly reduced the blood loss and bleeding time when compared with controls (no sealant, plasma, and a commercial product). The sealant also significantly reduced blood loss and bleeding time in rats that were anticoagulated with heparin. A mathematical model based on tensile strength and adhesion strength was developed to predict the bleeding time in the animal wound. Model predictions showed that the ability of the fibrin sealant to reduce bleeding time, and therefore blood loss, was limited by the adhesion strength.

EINLEITUNG: Die externe Stabilisierung von Venengrafts soll die Scherkräfte auf die Venenwand vermindern und dadurch die Ausbildung einer Neointimaproliferation reduzieren. In experimentellen Modellen wurde diese Hypothese im Kurzzeitversuch überprüft. Es fanden sich in diesem Zeitraum widersprüchliche Ergebnisse. Ziel unserer Untersuchung war es, in einem neuen Modell der arterialisierten segmentalen Vena-jugularis-Transposition auf die infrarenale Aorta den Einfluss einer externen Fibrinkleberstabilisierung auf die Neointimabildung des Venengrafts im Langzeitversuch darzustellen. MATERIAL UND METHODEN: Männlichen Wistar-Ratten wurden Segmente der Vena jugularis entnommen und in Flussrichtung, nach Entfernen eines Aortensegmentes, in die infrarenale Aorta eingebracht. Somit entspricht dieses einem Venenbypassmodell mit komplett arterialisiertem Venengraft. Vor

<p>Ekstrakcija zuba je intervencija prilikom koje se zub vadi iz svog leži&scaron;ta u zubnoj alveoli. Rana koja nastaje kao posledica ove intervncije je takvog oblika da njene ivice nije moguće približiti jednu drugoj , te zarasta per secundam intentionem. Ekstrakcija zuba ima za posledicu mnogobrojne promene na tvrdim i mekim tkivima alveolarnog nastavka u periodu od nekoliko meseci do godinu dana nakon intervencije. Savremena stomatologija se i dalje intenzivno bavi proučavanjem procesa zarastanja ekstrakcione rane iz potrebe da se &scaron;to bolje razumeju promene u tkivu koje nastaju po gubitku zuba da bi se mogle prevenirati i/ili usmeriti tako da se omogući kasnija lak&scaron;a protetska rehabilitacija pacijenata. Mnoge studije su pokazale efikasnost faktora rasta u tokom procesa zaceljivanja tkiva.Opisan je veliki broj tehnika za pripremu autolognih krvnih preparata koji sadrže faktore rasta, ali su njihova praktična primena i efikasnost su dalje nejasni zato &scaron;to svaka od ovih metoda dovodi do izrade različitog produkta sa različitom biologijom i potencijalnim indikacijama za upotrebu. Ekstrakcije mandibularnog trećeg molara spadaju u jednu od najče&scaron;ćih intervencija sa kojom se u svom radu svakodnevno sreću oralni i maksilofacijalni hirurzi. Ova hirur&scaron;ka procedura je povezana za postoperativnim efektima koji u velikoj meri utiču na kvalitet života pacijenta kao &scaron;to su bol, trizmus, edem, infekcija i alveolitis. U literaturi postoje dokazi da aplikacija nekog od autolognog krvnog preparata sa visokim sadržajem faktora rasta u određenoj meri može da pobolj&scaron;a proces zarastanja tkiva i da umanji neželjene propratne pojave hirur&scaron;ke intervencije nakon ekstrakcije mandibularnog trećeg molara. Cilj ovog rada je bio da utvrdimo da li primena autolognih krvnih preparata sa koncentrovanim faktorima rasta ubrzava stvaranje ko&scaron;tanog tkiva u ekstrakcionoj rani, kao i da li utiče na učestalost pojave alveolitisa i pojavu aproksimalinih parodontalnih džepova na susednim zubima nakon hirur&scaron;ke ekstrakcije donjeg trećeg molara. Studija je sprovedena kao prospektivna klinička studija split-mouth dizajna. U studiju je bilo uključeno 30 pacijenata kod kojih je indikovana ekstrakcija oba mandibularna treća molara i kod kojih su ovi zubi bilateralno u približno istom položaju u odnosu na drugi donji molar. Nakon hirur&scaron;ke ekstrakcije u jednu alveolu je aplikovan preparat koncentrovanih faktora rasta. Kontrolnu grupu u istraživanju činilo je 30 zubnih alveola u koje nije aplikovan preparat koncentrovanih faktora rasta. U eksperimentalnu grupu spadalo je 30 alveola u koje su aplikovani preparati koncentrovanih faktora rasta nakon ekstrakcije zuba. Pacijentima je prvi obavezan kontrolni pregled zakazivan za 7 dana nakon intervencije, tokom koga su uklanjane suture, a vr&scaron;en je i klinički pregled rane i parodontolo&scaron;kom sondom je proveravana dubina parodontalnog džepa na distalnoj povr&scaron;ini drugog molara. Druga postoperativna kontrola je zakazivana 4 nedelje nakon intervencije, a treća nakon 8 nedelja i na ovim kontrolama je merena dubina parodontalnog džepa na distalnoj povr&scaron;ini drugog molara. Ispitanicima su napravljena tri CBCT snimka operisanih regija i to po sledećoj dinamici- prvi snimak neposredno nakon ekstrakcije zuba, drugi 4 nedelje i treći 8 nedelja po intervenciji. Svaki CBCT snimak je analiziran da bi se prikupili željeni podaci: zapremina &scaron;upljine alveole koja je ostala nakon ekstrakcije zuba i gustina novostvorenog ko&scaron;tanog tkiva, &scaron;to su parametri na osnovu kojih procenjujemo proces zarastanja ko&scaron;tanog tkiva nakon intervencije. Ova metodologija je originalna , obzirom da su do sada kori&scaron;ćene dvodimenzionalne radiografske metode snimanja sa ciljem praćenja ko&scaron;tanog zarastanja nakon ekstrakcije zuba manje precizne i pouzdane. Dobijenu podaci su obrađeni odgovarajućim matematičko-statističkim postupcima. Najznačajniji rezultati istraživanja su zatim tabelarno i grafički prikazani. Na osnovu dobijenih rezultata do&scaron;li smo do zaključka da iako primena koncentrovanih faktora rasta dovodi do intenziviranja procesa ko&scaron;tanog zarastanja i smanjenja dubine parodontalnog džepa na distalnoj povr&scaron;ini susednih zuba, ta razlika nije statistički značajna. Obzirom da ni u jednom slučaju nije do&scaron;lo do pojave alveolitisa, nismo mogli zaključiti na koji način primena koncentrovanih faktora rasta utiče na učestalost ove komplikacije.</p> / <p>Tooth extraction is an intervention during which a tooth is removed from its socket. A wound that remains after this is of specific size and shape and it heals per secundam intentionem. Where once was a tooth, in following months and years, a large number of changes in composition of hard and soft tissues occure. Haeling of extraction wound in still in focus of contemporary dentistry, since it is imperative to understand all tissue changes in order to prevent and/or gide them and enable prosthodontic rehabilitation of the patient. Many studies confirm a benefitial effect of growth factors douring wound healing. A large number of techniques is developed to prepare autologous blood concentrates containing growth factors, like platelet-rich fibrin (PRF) , but their aplicability and efficancy are still unclear because each of these methods results in product with different biology and physical characteristics, as well as different potential indications. Third mandibular molar extraction is one of the most frequent interventions that oral and maxillofacial surgeon face in their everyday clinical practice. This procedure is usually followed by postoperative effects affecting such as pain, trismus, edema, infection and alveolitis. In contemporary literature there is enough evidence to suport beneficial role of autologous blood preparations in wound healing, and some authors even sugest that they can reduce incidence of postextraction complications afther third molar surgery. The aim of this study was to determin weather concentrated growth factors have beneficial effect on bone healing after tooth extraction, as well as their effect on the incidence of alveolitis and do they reduce pocket depth on distal side of adjacent tooth. This study was conducted as prospective clinical split-mouth designed study. 30 patients with both mandibular third molars indicated for the extraction, in similar position, were included in the study. On the same day surgical removal of both mandibular molars was performed, and in one socket PRF was placed. Patients were scheduled for a check-up and suture removals on the 7th postoperative day. During this visit, as well as after 4 and after 8 weeks, depth of distal pocket of the second molar was measured. CBCT was made on the day of surgery, 4 and 8 weeks afther surgery. On these radiographs volume of the bone defect was measured as well as density of newly formed bone tissue in the socket. This is original methodology, while previous studies used two-dimensional radiography methods in order to evaluate bone healing after tooth extractions, with less precision and liability. We processed and analyzed gained data using appropriate mathematical-statistical methods. According to our data we concluded that application of PRF in the extraction socket improves bone healing and reduces depth of pocket on the adjacent teeth, although this effects are not statistically significant. In our study, alveolitis did not occur neither in control nor in the experimental group, so we could not conclude if the application of PRF has any effect on prevention of this complication.</p>

名古屋大学博士学位論文 学位の種類 : 博士(医学)(論文) 学位授与年月日:平成3年2月1日 服部寿門氏の博士論文として提出された

No description available.