Background: Joint injuries are a complex matter. Due to the low blood flow to the tendons and ligaments, they take months or even years to heal; some fail to heal. This can be devastating for the elite athlete as well as for the labour worker or everyday person. Today, the devices that can detect an upcoming inflammation or injury, cost 15 000 US dollars and more. A cheaper technology would increase the access. This project is investigating the possibility to detect an upcoming inflammation through measuring the local skin temperature. Method: A model of an arm was built in Comsol Multiphysics, where a tennis elbow (lateral epicondylitis) was simulated through local temperature increase. Clinical tests were pursued on two healthy subjects, in order to gain knowledge on how the skin temperature behaves on healthy subjects. Results: At an internal temperature increase in the LE of 0.25 K, a temperature difference on the skin of 0.18 K was detected in the model. The clinical tests on healthy subjects indicated a correlation between the temperatures on and around the elbow joint. Discussion: The model results does not include any error sources, such as deviation in room temperature and factors affecting the subject´s body temperature, such as time of day, eating and exercising routines. The clinical tests show a pattern of the temperature distribution on and around the elbow joint, in healthy subjects. The fact that a pattern is present, is a presumption enabling to find deviations, caused by upcoming inflammation. Conclusion: The model is indicating that a local temperature increase in the LE is detectable at the skin surface. The clinical test indicates that the noise in the temperature data of a healthy person, is small enough to enable to detect a local temperature deviation. At a local skin temperature increase of more than 0.5 K, the results are indicating that the deviation is detectable. Analysing the model data, 0.5 K in skin temperature increase would mean a local temperature increase at the LE of approximately 0.7 K. This is before the stage of inflammation according to literature, which occurs at an increase of 1.5 to 2.2 K. Further studies would be interesting to make, in purpose of developing an affordable device that can detect if an inflammation is about to occur, and thereby enable the subject to stop the course. A prototype should be developed in order to make tests on more subjects. The equine industry is also a target group – the prototype may therefore be developed to fit both humans and horses. / Bakgrund: Ledskador är komplicerade. På grund av det låga blodflödet till senor och ligament, tar de månader eller år att läka; visa skador läker aldrig helt. Det här kan vara förödande för såväl elitatleter som arbetande och gemene man. Tekniker idag som kan detektera uppkommande inflammation eller skada, kostar 15 000 US dollar och mer. En billigare teknik skulle ha en större tillgänglighet. Det här projektet undersöker möjligheten att detektera en uppkommande inflammation genom att mäta den lokala skintemperaturen. Metod: En modell av en arm byggdes i Comsol Multiphysics, där en tennisarmbåge (lateral epikondylit) simulerades genom en lokal temperaturökning. Kliniska tester utfördes på två friska subjekt, för att skapa en bil av hur skintemperaturen varierar på friska personer. Resultat: Vid en inner temperaturökning om 0,25 K i LE, uppmättes en temperaturökning på huden om 0,18 K i modellen. De kliniska testerna på friska subjekt indikerade att en korrelation finns mellan temperaturerna på och runt armbågsleden. Diskussion: Resultat från modellen saknar felkällor, som exempelvis variation av rumstemperatur och andra faktorer som påverkar subjektets kroppstemperatur, som tid på dagen, mat- och träningsrutiner.De kliniska testerna uppvisar ett mönster av temperaturdistributionen hos friska subjekt på och runt armbågsleden. Att ett mönster finns, banar väg för att hitta avvikelser, som orsakas av uppkommande inflammation. Slutsats: Modellen indikerar att en lokal temperaturökning i LE är mätbar på huden. Det kliniska testet indikerar att bruset i temperaturdistributionen hos ett friskt subjekt, är litet nog för att möjliggöra detektion av en lokal temperaturavvikelse. Vid en lokal ökning av hudtemperatur med mer än 0,5 K, indikerar resultaten att avvikelsen är detekterbar. Vid analys av modellresultaten, innebär 0,5 K hudtemperatursökning en temperaturökningi LE om ungefär 0,7 K. Det är innan inflammation har brutit ut, som sker vid en ökning om 1,5 till 2,2 K. Vidare studier är intresssant att göra, i ändamål att utveckla en prisvärd produkt som kan detektera om en inflammation är på väg, och därigenom göra det möjligt för subjektet att stoppa förloppet. En prototyp behöver utvecklas för att kunna utföra tester på fler subjekt. Utöver människor, är hästindustrin en målgrupp – prototypen bör därför utvecklas för att passa båda grupperna.

Indiana University-Purdue University Indianapolis (IUPUI) / Tendinopathy is a common degenerative pathology that is characterized by activity related pain, focal tendon tenderness, intratendinous imaging changes, and typically results in changes in the histological, mechanical, and molecular properties of the tendon. Tendinopathy is difficult to study in humans, which has contributed to limited knowledge of the pathology, and thus a lack of appropriate treatment options. However, most believe that the pathology is degenerative as a result of a combination of both extrinsic and intrinsic factors. In order to gain understanding of this pathology, animal models are required. Because each tendon is naturally exposed to different conditions, a universal model is not feasible; therefore, an appropriate animal model must be established for each tendon susceptible to degenerative changes. While acceptable models have been developed for several tendons, a reliable model for the Achilles tendon remains elusive. The purpose of this dissertation was to develop an animal model of Achilles tendinopathy by investigating the individual and combined effects of an intrinsic and extrinsic factor on the rodent Achilles tendon. Rats selectively bred for high capacity running and Sprague Dawley rats underwent uphill treadmill running (an extrinsic factor) to mechanically overload the Achilles tendon or served as cage controls. Collagenase (intrinsic factor) was injected into one Achilles tendon in each animal to intrinsically break down the tendon. There were no interactions between uphill running and collagenase injection, indicating that the influence of the two factors was independent. Uphill treadmill running alone failed to produce any pathological changes in the histological or mechanical characteristics of the Achilles tendon, but did modify molecular activity. Intratendinous collagenase injection had negative effects on the histological, mechanical, and molecular properties of the tendon. The results of this dissertation demonstrated that the combined introduction of uphill treadmill running and collagenase injection did not lead to degenerative changes consistent with human Achilles tendinopathy. Intratendiouns collagenase injection negatively influenced the tendon; however, these changes were generally transient and not influenced by mechanical overload. Future studies should consider combinations of other intrinsic and extrinsic factors in an effort to develop an animal model that replicates human Achilles tendinopathy.

Thesis (PhD (Physiological Sciences))--University of Stellenbosch, 2007. / SUPERFICIAL digital flexor tendon injury has a serious negative impact on the competitive horse industry. Injured horses require up to a year of rest for recovery and likelihood of re-injury upon return to normal activity is as high as 80 %. Tendon healing requires (a) production of collagen by fibroblasts, to provide tensile strength and elasticity to the tendon, (b) minimisation of restrictive fibrosis, which compromises tendon gliding function and (c) minimisation of peritendinous adhesions. We review conventional treatments for tendon healing before exploring stem cell application as a therapeutic alternative. We promote the use of hematopoietic and mesenchymal stem cells derived from adult peripheral blood - as opposed to bone marrow-derived stem cells or embryonic stem cell sources - and review published research output in this regard. In conclusion, we outline our research objectives and present and discuss our results in the chapters that follow. Mononuclear cells - consisting of hematopoietic stem cells, mesenchymal stem cells and leucocytes – were isolated from the peripheral blood of sheep and horses through red blood cell lysis and blood plasma extraction. Cell counts and propidium iodide dye exclusion viability tests were conducted on the cell pellets. Sheep sub samples were tested for CD45 expression and horse sub samples for CD4 and CD11a/18 cell surface markers by flow cytometry for characterisation purposes. In both cases, separate sub samples were incubated with matched immunoglobulin (IgG) isotypes, conjugated to fluorescein isothiocyanate (FITC), to serve as controls. For the culture of mononuclear cells, 4.5 x 106 cells were selected for autologous sheep injections, 3 x 106 CD45- cells for allogeneic sheep injections (the latter excluding leucocytes that may induce an immune response) and 72 x 106 cells for horse injections. These cells were incubated with bromo-deoxyuridine (BrdU), cultured and subsets were extracted for a second round of cell counts and viability tests before being resuspended in blood plasma. For the horse samples an additional 1 x 106 mononuclear cells were incubated until reaching 60 % confluence and tested for myogenic differentiation. Low cell mortality and lack of fluorescence from IgG-FITC controls reflected effective protocols and a lack of false positive results. The fact that the equine cell population differentiated into myotubes verified the presence of mesenchymal stem cells in injections. We tested whether surgical incisions or collagenase injections best mimicked naturally occurring tendon injuries and compiled macroscopic and microscopic descriptions of tendon injury sites at seven weeks post-injury. The superficial digital flexor tendons of 27 sheep received an incision, a collagenase injection or a saline control injection. After one week a number of sheep were sacrificed while the remainder received further saline treatment and were sacrificed after another seven weeks. Tendons were examined through clinical observations, image analysis of maximum tendon diameter, mechanical testing and histological sectioning of affected tissues. Collagenase-induced injury resembled tendonitis more closely than surgically-induced injury. Collagenase-injured tendons (a) induced lengthier lameness in affected limbs, (b) were more swollen and difficult to palpate, (c) assumed the bow appearance characteristic of natural injury, (d) experienced extensive haemorrhage due to collagen lysis, (e) had decreased elasticity and capacity to carry loads and stress, (f) displayed decreased stiffness due to collagen fibre disruption and (g) developed severe inflammation. After seven weeks injured tendons displayed increased vascularisation in the areas of haemorrhage and in the adjacent collagen matrix. High inflammation rates and low collagen levels however still persisted. Collagenase injections were used to induce tendonitis in the superficial digital flexor tendons of 27 sheep. After one week these tendons received treatment with a control saline solution, autologous peripheral blood mononuclear cells (MNCs) or allogeneic peripheral blood CD45- MNCs. Healing rates were compared after a further seven week period by conducting ultrasonographic evaluations, clinical observations, image analyses of maximum tendon diameter, mechanical tests and histological investigations. Tendons treated with MNCs displayed an improvement in echogenicity and fibre linearity, higher and more organised collagen levels, stronger mechanical properties and less swelling. Although these improvements were not always significant, they provided strong evidence to suggest marked healing benefits over a longer time period. Collagenase injections were used to induce tendonitis in the superficial digital flexor tendons of four horses. After one week these tendons received treatment with either a control saline solution or autologous peripheral blood mononuclear cells (MNCs). Healing rates were compared after a further seven week period by conducting ultrasonographic evaluations, clinical observations, image analysis of maximum tendon diameter and histological investigations. Tendons treated with MNCs displayed significant improvements in fibre linearity in the direct vicinity of the lesion, as well as recovery rate thereof, and experienced less swelling when compared with their untreated counterparts. Healing trends suggested that, given a longer period of observation post-injury, more significant improvements may become apparent. Human adipose tissue is known be an easily accessible and high yielding source of multipotent mesenchymal stem cells. These stem cells could potentially be used for therapeutic advancement of tendon regeneration. Our first goal was to examine the in vitro myogenic differentiation potential of adipose-derived, adherent mononuclear cells (MNCs) from six adult sheep. The second goal was to characterise the population of cells isolated through various available ovine specific, non-mesenchymal stem cell surface markers, namely, CD1, CD31, CD34 and CD45. After incubation, only four of the six MNC cultures started to proliferate. These four cultures all exhibited high myogenic differentiation ability. The isolated cell populations did not express any of the non-mesenchymal stem cell specific cell surface markers. In conclusion, our data suggests that peripheral blood stem cells and adipose-derived stem cells are important candidate cell types for therapeutic application to improve tendon repair in horses and sheep. Sufficient time must be allowed following injury and prior to stem cell treatment (at least one month) and a controlled exercise program should be followed posttreatment. A larger sample size is required and at least six months of recovery before macroscopic and histological repair can be analysed more accurately and conclusively. Ultrasonography should be carried out on a continuous basis, as it is a non-invasive method of monitoring change over time.

The hands and feet account for half of the complexity of the musculoskeletal system, while the skin of the hand is specialised with many important structures. Much of the subtlety of the mechanism of the hand lies in the soft tissues, and the tactile and proprioceptive sensitivity depends on the large number of mechanoreceptors embedded in specific structures of the soft tissues. This thesis investigates synthetic materials and manufacturing techniques to enable building robots that reproduce the biomechanics and tactile sensitivity of vertebrates – histomimetic robotics. The material and mechanical anatomy of the hand is reviewed, highlighting difficulty of numerical measurement in soft-tissue anatomy, and the predictive nature of descriptive anatomical knowledge. The biomechanical mechanisms of the hand and their support of sensorimotor control are presented. A palate of materials and layup techniques are identified for emulating ligaments, joint surfaces, tendon networks, sheaths, soft matrices, and dermal structures. A method for thermoplastically drawing fine elastic fibres, with liquid metal amalgam cores, for connecting embedded sensors is demonstrated. The performance requirements of skeletal muscles are identified. Two classes of muscle-like bulk MEMS electrostatic actuators are shown theoretically to be capable of meeting these requirements. Means to manufacture them, and their additional application as mechanoreceptors are described. A novel machine perception algorithm is outlined as a solution to the problem of measuring soft tissue anatomy, CAD/CAE/CNC for layup of histomimetic robots, and sensory perception by such robots. The results of the work support the view that histomimetic robotics is a viable approach, and identify a number of areas for further investigation including: polymer modification by graft-polymerisation, automated layup tools, and machine perception.

Visou-se neste estudo criar uma forma de qualidade preditiva, buscando uma padronização das estruturas que compõem a articulação metacarpofalangeana, através do método de corte pós-congelamento e mensuração das estruturas nas medidas de espessura e largura. Então através da análise estatística foi possível gerar esse padrão para as seguintes estruturas: tendão flexor digital superficial, tendão flexor digital profundo, cápsula articular, ligamento extensor, ligamento intersesamoideo e ainda correlacionar os valores obtidos, visando agora à interligação de estruturas em seu estado de normalidade, para que pudesse ser aplicado em situações de injúrias. Dentro das estruturas analisadas a que mais apresentou variações foi a cápsula articular, talvez pela falta de padronização no momento da coleta (idade, função, histórico clínico). No caso da correlação não foi possível chegar a valores significativos, uma vez que a correlação apresentou-se baixa para a maioria das estruturas. / This study, try to create a predicative quality, looking for a pattern for the structures that compose the metacarpophalangeal joint, using the method of cutting after freezing and making the measures of the structures in denseness and largeness. Then through the statistics analysis it was possible to create the pattern to the following structures: superficial digital flexor tendon, deep digital flexor tendon, articular capsule, extensor ligaments, intersesamoids ligaments and still make the correlation with the numbers that was found, trying to get the interconnect of the structures in the normal position, to be used in injuries situations. The articular capsule was the structure that shows the highest variation, maybe because there was not a pattern at the moment of collecting (age, function, clinical historical). In the correlation it was not possible to find significant values, once the correlation was low to the majority of structures.

Surgical repair of torn rotator cuff tendons have a high rate of failure and does not address the underlying pathophysiology. Tissue engineering strategies, employing the use of multipotent progenitor cells or growth factors, represent potential therapies to improve the outcome of rotator cuff surgery. The use of glycosaminoglycan-based biomaterials in these therapies may enhance the effectiveness of cell and growth factor delivery techniques. Furthermore, understanding the cellular and molecular mediators in tendon overuse can help elucidate the causes of tendon degeneration. Thus the overall goals of this dissertation were to 1) develop heparin-based biomaterials to enhance cell pre-culture and maintain growth factor bioactivity and 2) characterize the histological and enzymatic changes in a supraspinatus tendon overuse model. To investigate the use of heparin in enhancing dynamic signaling, mesenchymal stem cells (MSCs) were encapsulated in heparin-containing hydrogels and evaluated for differentiation markers when cocultured with a small population of differentiated cells. To probe the effect of sulfation of heparin on the interactions with protein, selectively desulfated heparin species were synthesized and evaluated for their ability to bind and protect proteins. Finally, to develop a tendon overuse model that can become a test bed for testing future targeted therapeutics, an animal model was evaluated for tissue damage and protease activity. Together these studies represent a multi-pronged approach to understanding how tendon tissues become degenerative and for developing technologies to improve the biological fixation of tendon to bone in order to reduce the need for revision surgeries.

Visou-se neste estudo criar uma forma de qualidade preditiva, buscando uma padronização das estruturas que compõem a articulação metacarpofalangeana, através do método de corte pós-congelamento e mensuração das estruturas nas medidas de espessura e largura. Então através da análise estatística foi possível gerar esse padrão para as seguintes estruturas: tendão flexor digital superficial, tendão flexor digital profundo, cápsula articular, ligamento extensor, ligamento intersesamoideo e ainda correlacionar os valores obtidos, visando agora à interligação de estruturas em seu estado de normalidade, para que pudesse ser aplicado em situações de injúrias. Dentro das estruturas analisadas a que mais apresentou variações foi a cápsula articular, talvez pela falta de padronização no momento da coleta (idade, função, histórico clínico). No caso da correlação não foi possível chegar a valores significativos, uma vez que a correlação apresentou-se baixa para a maioria das estruturas. / This study, try to create a predicative quality, looking for a pattern for the structures that compose the metacarpophalangeal joint, using the method of cutting after freezing and making the measures of the structures in denseness and largeness. Then through the statistics analysis it was possible to create the pattern to the following structures: superficial digital flexor tendon, deep digital flexor tendon, articular capsule, extensor ligaments, intersesamoids ligaments and still make the correlation with the numbers that was found, trying to get the interconnect of the structures in the normal position, to be used in injuries situations. The articular capsule was the structure that shows the highest variation, maybe because there was not a pattern at the moment of collecting (age, function, clinical historical). In the correlation it was not possible to find significant values, once the correlation was low to the majority of structures.

This thesis is drafting static protection church horizontal pretension, especially at the level of foundations and walls. Furthermore, the design of a new increase the stiffness of reinforced concrete towers and other prestress. The role was also producing construction drawings for the design of static security.

Made available in DSpace on 2016-01-26T12:51:52Z (GMT). No. of bitstreams: 1 rogerioleonebuchaim_tese.pdf: 3407631 bytes, checksum: 87786b69303a26860816554562d2cdab (MD5) Previous issue date: 2004-05-17 / The present study was aimed at examining the biocompatibility of anionic collagen matrices, their local bone response following implantation in surgically-created bone defects and also the influence of the collagen fiber orientation in the neoformed bone tissue. Seventy two rats ( Rattus norvegicus albinus ) were used in this experiment. The animals were divided into four experimental groups: Group 1 (control), without implants; Group 2, pericardium medullar implants, 12 hours; Group 3, medullar implants of tendon, 24 hours, with the bigger axes of collagen fibers parallel to the bigger axes of the tibia; and Group 4, medullar implants of tendon, 24 hours, with the bigger axes of collagen fibers perpendicular to the bigger axes of the tibia. After the experimental surgery, the evolution of the repair process was microscopically evaluated in 7, 15 and 30 days post-surgery. The results demonstrated the implanted matrices to be biocompatible and to function as a scaffold inducing the formation of bone, mainly in Group 4. At first, the cellularity follows the arrangement of collagen fibers, obtaining a growing multidirectional arrangement, suggesting that the direction and the orientation are related to the direction and to the magnitude of the stress applied to the bone. / Este estudo apresentou como objetivo, examinar a biocompatibilidade de matrizes de colágeno aniônico, sua resposta óssea local após implantação em defeitos ósseos criados cirurgicamente e a influência da orientação das fibras colágenas no tecido ósseo neoformado. Foram utilizados 72 ratos (Rattus norvegicus albinus) divididos em 4 grupos experimentais de 6 animais cada: Grupo 1 (controle), sem implante; Grupo 2, implante medular pericárdio 12 horas; Grupo 3, implante medularde tendão 24 horas, com o maior eixo de suas fibras colágenas direcionados paralelamente ao maior eixo da tíbia e , Grupo 4, implante medular de tendão 24 horas, com o maior eixo de suas fibras colágenas direcionadas perpendicularmente ao maior eixo da tíbia. A evolução do processo de reparo, após a cirurgia experimental, foi avaliada microscopicamente com 7, 15 e 30 dias pós-operatórios. Os resultados demosntraram que as matrizes implantadas são biocompatíveis e funcionam como uma matriz tridimensional induzindo a formação de osso, maior no grupo 4. a celularidade, inicialmente, acompanha o arranjo das fibras colágenas, adquirindo um arranjo multidirecional crescente, sugerindo que a direção e a orientação estão relacionadas com a direção e a magnitude do stress aplicado sobre o osso.

Η πλειονότητα των ερευνητών/ειδικών του αντισεισμικού σχεδιασμού συμφωνεί πως μια υπολογιστική διαδικασία που θα έχει ως βασική παράμετρο της απόκρισης τις σεισμικές μετακινήσεις θα είναι πιο ορθολογική και πιθανότατα πιο οικονομική απ’ τη συμβατική μεθοδολογία σχεδιασμού βάσει δυνάμεων. Η έλλειψη μιας μεθοδολογίας αντισεισμικού σχεδιασμού γεφυρών βάσει μετακινήσεων που να είναι απλή, εφικτή και συμβατή με την εφαρμοζόμενη πρακτική και η απουσία πρότασης σχεδιασμού των περιοχών του φορέα βάσει μετακινήσεων, αποδεικνύει το γνωστικό κενό που υπάρχει σ’ αυτή την περιοχή του αντισεισμικού σχεδιασμού. Η παρούσα εργασία επιχειρεί να συμβάλλει στην πλήρωση αυτού του κενού και προς τούτο προτείνει μια νέα μεθοδολογία. Αναφέρεται σε (μή-μονωμένες) γέφυρες σκυροδέματος και περιλαμβάνει μια απλή διαδικασία για την εκτίμηση των απαιτούμενων ανελαστικών παραμορφώσεων, τόσο των βάθρων, όσο και των περιοχών του φορέα - κάνοντας χρήση ελαστικής φασματικής ανάλυσης και επεκτείνοντας τον κανόνα των "Ίσων Μετακινήσεων" στο τοπικό επίπεδο. Η διαδικασία αναπτύσσεται και βαθμονομείται βάσει (σχεδόν δύο χιλιάδων) μή-γραμμικών δυναμικών αναλύσεων (με εν χρόνω ολοκλήρωση) αντιπροσωπευτικών γεφυρών, τριών έως πέντε ανοιγμάτων. Όμως για την εφαρμογή της απαιτούνται μόνο ελαστικά εργαλεία. Σε αντίθεση με τις έως τώρα ερευνητικές προσπάθειες, όπου γίνεται η απλουστευτική παραδοχή γραμμικής συμπεριφοράς του φορέα, στην παρούσα έρευνα δίνεται έμφαση στην προσομοίωση των περιοχών του φορέα και λαμβάνονται υπ’ όψιν οι μή-γραμμικότητές του. Από την εφαρμογή του διαπιστώνεται ότι ο προτεινόμενος σχεδιασμός βάσει μετακινήσεων προσφέρει πολύ οικονομικότερα ποσοστά όπλισης (από 1/2 έως 1/7 στο διαμήκη οπλισμό και από 1/1 έως 1/3 στον εγκάρσιο οπλισμό), χωρίς να επιβαρύνει ουσιαστικά την επιτελεστικότητα της γέφυρας - η υπεραντοχή των γεφυρών που σχεδιάζονται με την προτεινόμενη μεθοδολογία είναι πρακτικά ισοδύναμη με την υπεραντοχή των συμβατικά σχεδιασμένων γεφυρών. Η παρουσίαση της μεθοδολογίας περιλαμβάνει την περιγραφή της διαδικασίας σχεδιασμού υπό μορφή αλγόριθμου (Κεφ. 2), του τρόπου εφαρμογής της στην πράξη (διαδικασία προσομοίωσης, παραδείγματα σχεδιασμού: Κεφ. 3), του θεωρητικού υποβάθρου βάσει του οποίου αναπτύχθηκε (Κεφ. 4), των προβλημάτων της συμβατικής μεθοδολογίας (παραδείγματα σχεδιασμού βάσει δυνάμεων: Κεφ. 3) και των κενών που διαπιστώνονται στην τεκμηρίωση της συμβατικής μεθοδολογίας (Κεφ. 4). Η αποτίμηση του σχεδιασμού (Κεφ. 3) δεκαέξι αντιπροσωπευτικών γεφυρών (οκτώ σχεδιασμένων βάσει μετακινήσεων και οκτώ συμβατικά σχεδιασμένων), παρουσιάζεται υπό μορφή παράλληλης σύγκρισης της επιτελεστικότητας και συνηγορεί υπέρ των πλεονεκτημάτων της νέας μεθοδολογίας. Στα Παραρτήματα δίνονται πληροφορίες για τα υπολογιστικά εργαλεία που αναπτύχθηκαν για την προσομοίωση και την ανάλυση των γεφυρών (επέκταση προγράμματος ANSRuop). / The majority of seismic design researchers/specialists concludes that displacement-based design methodologies reduce the uncertainty of the design process and probably lead to less expensive structures. The absence of a simple displacement-based seismic design procedure for bridges that will be feasible and compatible with the current design practice and the nonexistence of a proposal for the displacement-based design of the deck indicate the gap of knowledge in this field of earthquake engineering. This thesis attempts to contribute to the reduction of this gap and for this scope proposes a new methodology. The procedure focuses on bridges with concrete piers monolithically connected to a prestressed concrete continuous deck and comprises simple steps for the estimation of the inelastic/nonlinear deformations of both the piers and the deck - through elastic modal response spectrum analysis, extending the applicability of the "equal displacement" rule to the level of member deformations. About two thousands nonlinear dynamic (time-history) analyses of several representative bridges (with deck of three or five spans) are used for the development and the calibration of the procedure. However, for the application of the methodology only elastic modal response spectrum analysis is needed. Contrary to other current researches, which adopt the hypothesis of deck elastic response, the nonlinearities of the deck are modeled. The proposed displacement-based procedure offers lower reinforcement ratios (from 1/2 to 1/7 for the longitudinal reinforcement and from 1/1 to 1/3 for the transverse reinforcement) at no detriment to the expected seismic performance - the global overstrength of the bridges which are designed with the proposed procedure is practically equivalent to the global overstrength of the conventionally designed bridges (current force-based design). The step by step description of the design algorithm (Chap. 2) is followed by the practical application of the methodology (modeling aspects, design examples: Chap. 3), the conceptual justification (Chap. 4), the deficiencies of the conventional design procedure (force-based design examples: Chap. 3) and the fallacies in the justification of the conventional design methodology (Chap. 4). Comparative performance-based design evaluation (Chap. 3) of sixteen representative bridges (eight bridges subjected to alternative seismic design) indicates the benefits of the proposed procedure. The computational capabilities which were developed for the modeling and the analysis of the bridges are described in the appendices (upgrade of program ANSRuop).