Made available in DSpace on 2014-06-11T19:23:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-14Bitstream added on 2014-06-13T20:11:30Z : No. of bitstreams: 1 iamaguti_ls_me_botfmvz.pdf: 753163 bytes, checksum: 213a9899967bd02b03e8f98c82bf083c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi avaliar a aplicação de membrana biossintética de celulose (MBC) nacional, após a realização de trocleoplastia experimental em cães, com intuito de verificar se o uso desta poderia favorecer a migração de células com potencial condrogênico, assim como ocorre no tecido ósseo. A evolução pós-operatória dos cães foi analisada com especial interesse nos processos de reparação frente ao defeito osteocondral, estabelecendo as vantagens e desvantagens do uso do biomaterial. Foram utilizados 12 cães (Canis familiaris) adultos, sadios e sem alterações no aparelho locomotor. Todos os animais foram submetidos ao procedimento de trocleoplastia bilateral, sendo que a MBC foi aplicada no membro esquerdo. Os animais foram avaliados clínica e radiograficamente aos 15, 30, 60 e 90 dias de pós-operatório. A função locomotora do membro foi avaliada em escores pré-definidos, nos referidos momentos. A avaliação macroscópica da articulação foi realizada, nos momentos pré-estabelecidos, seguida da artrotomia exploratória, bem como da coleta de biópsia para o exame microscópico. Todos os animais apresentaram função normal dos membros nos momentos avaliados. Não houve diferença clínica e radiográfica entre os grupos controle (GC) e tratado (GT). Na avaliação histopatológica, aos 30 dias, notou-se intensa celularidade em ambos os grupos, sendo que no GC esta era constituída por fibroblastos ativos e no GT por condrócitos imaturos, formando um tecido conjuntivo mais organizado. O GC apresentava fibrose e muitos fibroblastos aos 60 dias, enquanto o GT apresentava maior número de condrócitos. Aos 90 dias, constatou-se formação de tecido do tipo fibrocartilaginoso maduro em ambos os grupos. Histomorfometricamente, o GT apresentou melhor resposta ao processo de reparação nos momentos iniciais quanto ao número de células e espessura do tecido... / The aim of this study was to evaluate the application of national biosynthetic cellulose membrane after experimental trochleoplasty, to verify if its utilization could support chondrogenic cells migration like occurs in osseous tissue. The advantages and disadvantages of the use of this biomaterial were evaluated through the observation of the reparative process of the osteochondral injury. Twelve adult healthy dogs (Canis familiaris) were used. All dogs were submitted to trochleoplasty in both pelvic limbs and the biosynthetic cellulose membrane was applied in the left limb. Clinical and radiographic evaluation was performed at 15, 30, 60 and 90 postoperatively. The locomotor function of the limb was evaluated in scores on the differents moments. The joint macroscopic evaluation was performed before exploratory arthrotomy and biopsy for microscopic exam. All dogs showed normal function of the limbs in all differents moments. Radiographic results showed no difference in control (CG) and treated groups (TG). Microscopic results showed at 30 days an increase of the celularity in both groups was observed. In the CG it was constituted by active fibroblasts and in TG by immatures condrocytes forming a more organized connective tissue. In the CG a fibrous tissue and many fibroblasts appear at 60 days and in the TG more condrocytes appear. A mature fibrocartilaginous tissue formed in both groups at 90 days. Histomorphometrically, TG presents better response of repair process in the fist moments as the number of cells and the tissue thickness. The biosynthetic cellulose membrane didn't cause deleterious effects showing good adaptation in intrarticular environment...(Complete abstract, access undermentioned eletronic address)

Orientador: Joni Augusto Cirelli / Banca: José Eduardo Cezar Sampaio / Banca: Elton Gonçalves Zenóbio / Resumo: Este trabalho teve como objetivo determinar as reações teciduais em lesões de furca Grau II em 2ºs pré-molares de cães após tratamento com matriz mineral óssea bovina e membrana absorvível e movimentação ortodôntica de translação para mesial. Foram criadas lesões de furca Grau II nos 2º pré-molares superiores de 4 cães, totalizando 8 lesões. Após 75 dias, estas foram tratadas pela técnica de Regeneração Tecidual Guiada com membrana absorvível associada ao preenchimento com matriz mineral óssea bovina. Deu-se início ao controle de placa com gel de clorexidina 0,2% 5 vezes por semana até o final do estudo. Após 2 meses do tratamento, os 2ºs pré-molares foram divididos aleatoriamente em dois grupos (teste e controle) e foi instalado aparelho ortodôntico em ambos os lados, sendo os 3ºs pré-molares e caninos superiores usados como ancoragem. No lado teste a movimentação ortodôntica foi realizada durante 3 meses. Os animais foram sacrificados, e os 2ºs pré-molares removidos em bloco e processados para análise histológica. Não houve diferenças estatisticamente significantes entre os grupos em relação a área total de preenchimento ósseo, de biomaterial e extensão linear de regeneração periodontal na superfície radicular. Porém, houve uma tendência do grupo teste apresentar maior quantidade óssea e menor quantidade de biomaterial, além de deslocamento do biomaterial para o lado de pressão na região de furca, no grupo teste. / Abstract: The aim of this study was to establish the tissue reactions on Degree II furcation lesions in the 2nd premolars of dogs after treatment with bovine osseous mineral source, absorbable membrane and orthodontic movement of translation to mesial and also evaluate the effect of movement on the grafting material used. It was produced Degree II furcation lesions in upper second premolars of 4 dogs, resulting in 8 lesions. After75 days, they were treated by the method of Guided Tissue Regeneration with absorbable membrane associated with bovine osseous mineral source. The plaque control was started with 0,2% chlorhexidine gel, 5 times a week until the end of the study. After 2 months of treatment, the second premolars were randomly divided in two groups (test and control) and it was installed orthodontic appliance in both sides, using the third premolars and upper canine as anchorage. The orthodontic movement was achieved only in the test side, during 3 months. The animals were sacrificed and the second premolars were removed in block and processed for histological analysis. There weren't any differences that were statistically significant among the groups with relation to the total area of osseous filling, biomaterial and linear periodontal regeneration. However, there was a trend of the group to present more osseous amount and less biomaterial amount, besides the dislocation of the biomaterial for the furcation pressure side. The orthodontic movement could be done without intercurrences. Key- words: Periodontics; Guided tissue regeneration; Biocompatible materials; Orthodontic. / Mestre

Orientador: Joni Augusto Cirelli / Banca: Luís Carlos Spolidorio / Banca: Álvaro Francisco Bosco / Banca: Marcio Fernando de Moraes Grisi / Banca: Elton Gonçalves Zenóbio / Resumo: O objetivo do presente estudo foi avaliar histomorfometricamente o efeito do plasma rico em plaquetas (PRP), associado a enxerto ósseo autógeno e a membrana absorvível (Resolut®), no tratamento de lesões de furca grau III. Foram criados defeitos cirúrgicos nos 3os pré-molares inferiores (P3) de cinco cães, de ambos os lados, totalizando 10 dentes. Após um período de três meses de cronificação, as lesões foram divididas aleatoriamente em dois grupos de tratamento. (1) Grupo teste: PRP + enxerto ósseo autógeno + membrana; (2) Grupo controle: enxerto ósseo autógeno + membrana. Após um período de cicatrização de 90 dias, os animais foram sacrificados. A análise histológica, a partir da marcação, mostrou formação de novo cemento celular, mínima quantidade de novo osso e ligamento periodontal, em ambos os grupos. Nenhuma diferença estatisticamente significante foi observada entre os grupos teste e controle. A associação do PRP ao enxerto ósseo autógeno e membrana, ou somente, do enxerto ósseo autógeno e membrana, não apresentou vantagens estatisticamente significantes no tratamento das lesões, resultando em preenchimento parcial das furcas e regeneração periodontal limitada à marca experimental das lesões. / Abstract: The objective of this study was to evaluate histomorphometrically the platelet-rich plasma (PRP) effects, associated with autogenous bone graft and absorbable membrane (Resolut®), for the treatment of Class III furcation defects, in 5 dogs. Surgical defects were created in the 3nd mandibular premolars (P3) on both sides, of each dog, totaling 10 teeth. After a period of three months of chronified, the defects were randomly divided in two treatment groups. (1) Group Tests: PRP + graft bone autogenous + membrane; (2) Group Control: graft bone autogenous + membrane. Animals were sacrificed after 90 days healing. Histologic evaluation revealed new cellular cementum, low amount of bone and periodontal ligament formation in both groups, starting from the demarcation. No statistically significant difference was observed between Groups Test and Control. PRP + autogenous bone graft + membrane or autogenous bone graft + membrane no present statistically significant advantages on the lesions treatment, resulting in furcation partial filling and periodontal regeneration limited to the experimental mark of the lesions. / Doutor

Orientador: Eliana Aparecida de Resende Duek / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-10T00:47:14Z (GMT). No. of bitstreams: 1 Moura_LucasAlves_M.pdf: 3634046 bytes, checksum: 536a898e97f786f07e4ccf738d9d67e5 (MD5) Previous issue date: 2007 / Resumo: A regeneração tecidual guiada (RTG) é uma técnica utilizada na Periodontia para permitir a neoformação de um novo aparato de inserção periodontal do dente (osso alveolar, ligamento periodontal e cemento). Na Periodontia, a utilização de polímeros biorreabsorvíveis vem ganhando confiabilidade e importância devido a não necessidade de uma segunda intervenção cirúrgica para remover a membrana, porém poucas membranas atendem a todos os critérios da RTG, que são biocompatibilidade, exclusão celular, manutenção do espaço a ser regenerado, integração à atividade tecidual, facilidade de utilização e atividade biológica. Um polímero biorreabsorvível muito estudado é o poli (L-ácido láctico) (PLLA), porém ele é polímero semicristalino muito rígido e com longo período de degradação, contudo ao se adicionar em sua composição um plastificante, o tri-etil-citrato, a membrana resultante seria mais flexível, microporosa e teria seu tempo de degradação reduzido. Esta pesquisa avaliou, através de estudo in vivo, a resposta inflamatória e a manutenção de um espaço vital para a regeneração óssea sob membranas de PLLA/tri-etil-citrato, em três diferentes proporções polímero/plastificante, implantadas na calota craniana de coelhos, analisando, assim, a capacidade destas membranas em se adaptar aos critérios da RTG periodontal. Paralelamente ao estudo in vivo, foram realizados estudos da degradação in vitro, com ensaios mecânicos de tração, de microscopia eletrônica de varredura e de calorimetria diferencial de varredura (DSC). Notou-se que as membranas de concentração PLLA/tri-etil-citrato de 85/15 apresentaram características mais adequadas para a RTG periodontal tanto no estudo in vivo quanto no in vitro / Abstract: Guided tissue regeneration (GTR) is a technique used in the periodontal practice to allow the neoformation of a new apparatus of teeth periodontal attachment (alveolar bone, periodontal ligament and cementum). In Periodontology, the use of bioresorbable polymers is gaining trustworthiness and importance due the non required second surgical intervention to remove the membrane, however few membranes fit in all GTR criteria, which are biocompatibility, cellular exclusion, space maintainer, integration to tissue activity, easy usage and biological activity. A bioresorbable polymer very studied is poly(L-lactic acid) (PLLA), however it is a very rigid semicrystalline polymer and with a long degradation period, but by adding in its composition a plasticizer, the tri-ethyl-citrate, the resultant membrane would be more flexible, microporous and would have its degradation time reduced. This research evaluated, through in vivo study, the inflammatory response and the maintenance of a vital space for bone regeneration under PLLA/tri-ethyl-citrate membranes, in three different polymer/plasticizer proportions, implanted in rabbits calvarial bone, analyzing, thus, the capacity of these membranes in adapting to the criteria of periodontal GTR. Simultaneously to this study, it had been carried out studies of in vitro degradation, with mechanical testing, scanning electronic microscopy and differential scanning calorimetry (DSC). It was observed, that the highest concentration membranes PLLA/tri-ethyl-citrate (85/15) showed themselves more adequate characteristics for the periodontal GTR on in vivo study as well on in vitro / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Corals combine photosynthesis and calcification in an intricate and delicately balanced relationship to form large biomineralized structures that are dominant features of tropical coastlines worldwide. Coral reefs have great scientific and economic importance but have recently experienced widespread decline attributed to increasing anthropogenic pressure on reef systems. Physical damage events, such as ship groundings, when coupled with existing nutrient stress and changing global climate present a poor outlook for successful natural recovery of reef communities. The main goal of the proposed research is to better understand how environmental factors, both local and global, affect the coral holobiont and influence overall coral fitness. The target species of this research, Montastraea cavernosa and Porites astreoides, are important and widespread Caribbean reef-builders. While it has been shown that nutrient and pCO2 stress affect coral growth and calcification, study of specific effects on coral tissue and reproductive success has not received significant attention in the literature despite considerable current interest. This study addresses this data gap in quantitatively examining the effect of elevated nutrients and pCO2 on 1) P. astreoides recruit survivorship, development, early calcification, and symbiotic zooxanthellae morphology; 2) M. cavernosa and P. astreoides wound regeneration, tissue characteristics over time at the histological and ultrastructural level, and trends in symbiotic zooxanthellae morphology; and 3) survival, growth and histological/ultrastructural characteristics of M. cavernosa and P. astreoides fragments transplanted to the field and in the laboratory. Histological and ultrastructural observations from corals transplanted to the field are then compared to ex-situ laboratory experimental corals. In the fleshy and large-polyped faviid M. cavernosa, healing of a linear wound was characterized by granulation of new tissue across the wound site, facilitated by coalescent granular amoebocytes. The wound healing strategy of this species appears to progress with wound closure and re-epithelialization before calcification resumes, as actively calcifying calicodermis was generally not observed at the healing front. Tissue regeneration in the small-polyped P. astreoides was characterized by formation of multiple islands of eosinophilic healing fronts along the depth of the wound track, and an accumulation of granular amoebocyte cells in regenerating tissue. The wound healing strategy of this species appeared to result in re-epithelialization of exposed body wall without necessarily closing the wound. Elevated pCO2 significantly reduced survivorship in P. astreoides recruits, and both nutrient enrichment and elevated pCO2 significantly reduced wound regeneration rate in M. cavernosa and P. astreoides. In both species, phosphate enrichment had the greatest deleterious effect on wound repair. A significant application of this study is the identification of possible zooxanthellar morphological indices of elevated nutrients and ocean acidification. The similarity in starch, lipid and uric acid accumulation patterns in Symbiodinium sp. from P. astreoides recruits and coral fragments of both species indicate a correlation between these anthropogenic stressors and the intracellular accumulation of excess carbon and nitrogen by the symbiont. Zooxanthellar carbon accumulation, in the form of starch and/or lipid, was the greatest under elevated nitrate. Zooxanthellar nitrogen accumulation, in the form of uric acid, was the greatest under elevated CO2. Comparison of zooxanthellar metrics between the field corals (P. astreoides, and M. cavernosa) and ex-situ corals and recruits indicated that carbon accumulation in Symbiodinium from field corals was consistently significantly less than in the ex-situ experimental P. astreoides recruits and M. cavernosa fragments exposed to elevated nitrate. This indicates that the field corals were likely not exposed to elevated nitrate at the time of collection. Both M. cavernosa and P. astreoides adults in the field accumulated significantly less uric acid than their counterparts in the tissue repair experiment, indicating that the field corals were exposed to higher pH and lower CO2 than the ex-situ corals. These results suggest that the field corals were not exposed to nutrient concentration profiles similar to the experimental treatments, particularly elevated nitrate. However, histological metrics indicated that the transplanted corals were subjected to increasing sedimentation stress over time. Overall, nitrate was found to affect recruits and adults on a similar scale, while phosphate and pCO2 affected carbon and nitrogen storage more in recruits compared to adults. While nutrients and pCO2 had no mechanistic effect on regeneration at histological level, ultrastructural metrics indicate an impact on the mutualistic energy exchange between the symbiotic partners, partially decoupling symbiosis. Effects were generally found to be greater in P. astreoides compared to M. cavernosa, and the unique life history strategy of the subject species and differences in their endosymbiont physiology reveal distinct responses to elevated nutrients and pCO2. Although the laboratory findings were not necessarily applicable to field observations, they provide insight into factors that may influence fragment success in the field. Quantitative assessment of the effect of elevated nutrients and pCO2 is thus useful in management decisions involving water quality standards, and is essential in the prediction of future coral condition and resilience.

No description available.

No description available.

No / The resurgence of larval biotherapy as a debridement tool in wound management has been accompanied by several clinical reports highlighting concomitant tissue regeneration. Studies employing in vitro cell motility assays have found that purified excretory/secretory (ES) products from Greenbottle larvae (blowfly, Lucilia sericata) are motogenic for human dermal fibroblasts when used as a supplement in culture media. The objective of the present study was to determine whether ES delivered using a prototype hydrogel wound dressing induced similar motogenic effects on fibroblastic (3T3) and epithelial cells (HaCaTs) comprising a scratched-monolayer wound model. Quantitative analysis by MTT assay failed to detect significant mitogenic effects of ES on either cell type. Quantitative image analysis revealed that ES exposure markedly accelerated wound closure through a motogenic effect on both fibroblasts and keratinocytes. Quantitative histochemical analysis detected significantly higher phosphotyrosine (pTyr) expression in ES-exposed cell cultures than in controls; moreover immunocytochemistry revealed conspicuously raised levels of pTyr expression in cells located at the wound margin. By attenuation with a panel of enzyme inhibitors these effects were attributed to the protease components of ES. The present results suggest that controlled delivery of ES as a follow-up to maggot debridement therapy may be an effective therapeutic option for stimulation of tissue regeneration in wound management.

Thesis (PhD)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Diabetes Mellitus (DM) is synonymous with "B-cell failure". Ligation of the pancreatic duct distally to its confluence into the bile duct has been shown to induce endocrine tissue regeneration from a number of probable sources. The cells responsible for regeneration are supposed to possess either dormant pluripotent stem cell ability and/or the plasticity to undergo metaplasia to form new and surplus endocrine tissue able to replace pathologically and/or experimentally compromised pancreas. The sequence of events (cell lineage) during this process of neogenesis, has been the source of controversy for quite some time as various studies suggest that the cell lineage differs from in vivo and in vitro studies, according to experimental model and species of laboratory animal. The object of this study was to utilise an established experimental laboratory animal model to study islet morphological changes, neogenesis and or both in vivo. Further aims of the study were to determine the extent, sequence and magnitude of pancreatic duct ligation (PDL) induced endocrine neogenesis/morphogenesis in a laboratory rat model using occlusive pancreatic duct ligation. PDL's were performed on six groups of 25 normal adult Sprague-Dawley (SD) rats (300g+) according to the method of Hultquist and Jonsson (1965). Experimental animals were sacrificed at 12 hr intervals from day one post-PDL to day 10 and every 24 hrs thereafter to day 14 as described by Wang, Klëppel, Bouwens (1995). Animals received BrdU (a thymidine marker and cell proliferation indicator) 50mglkg intraperitoneally as described by Wang et al. (1995), one hour prior to removal of the pancreas after which it was fixed in Bouin's solution and histologically processed. Seven consecutive 3-6 urn thick serial sections were sequentially stained with H & E, insulin (I), glucagon (G), somatostatin (ST), pancreatic polypeptide (PP), neuropeptide tyrosine (NPY) and peptide tyrosine tyrosine (PYY). Immunolabeling was done according to the method of Guesdon, Temynck , Avrameas (1979). Double immunolabeling for BrdU and each pancreatic peptide was performed on the sections on days 3,5, 7, 9 and 11 as described by Wang et al (1994). Cellular transformation between one and 3Yz days was characterised by simultaneous total deletion and/or transdifferentiation of the acinar compartment and the appearance of immunoreactive cells for I (11.53 ±1.5%), G (1.85 ±0.8%), pp (1.50 ±0.09%), and ST (1.96 ±0.24%). Changes in the endocrine composition in existing islets, occurred along a pathway that saw PP- and ST-cells invading the islet core, islet mantle glucagon deletion and random appearance of all endocrine cell types within the inter-islet interstitium on day 3Yz. Days 4 to 6Yz saw further endocrine expansion while days 7 to 14 were distinguished by islet reconstitution and consolidation. NPY immunoreactivity appeared on day 4Y2 and persisted intermittently throughout while PVV first appeared on day 4 and disappeared after day 7Yz. The results suggest that PDL firstly induced the development of endocrine tissue distributed haphazardly throughout the space previously occupied by acinar parenchyma. Secondly, the appearance of insulin is preceded by the appearance of PP, glucagon and somatostatin by 24-hours. A still to be determined proportion of the ligation induced endocrine formation appeared to be associated with existing islets, resulting in a number of very large islets, some of which might have secretory access through the glomerularlike capillary network known to occupy the islet core. The remainder appeared to form separate "new" islets, which have a dubious access to the blood stream. In conclusion, if it is true that the pancreas can regenerate some of its endocrine tissue then it has potential clinical implication for the stabilising of diabetes mellitus. Ligated exocrine pancreatic tissue, devoid of its acinar component, has been shown to contain notable quantities of insulin positive cells. This presents intriguing possibilities as an alternative for donor tissue, usually obtained from rat foetuses, during foetal rat pancreas transplantation studies. Pancreas tissue harvested from duct ligated rats could replace the foetal tissue currently used in the treatment of experimental diabetes mellitus in laboratory animals in this laboratory. / AFRIKAANSE OPSOMMING: Diabetes Mellitus is sinoniem met B-sel disfunksie. Endokriene regenerasie kan segmenteel bewerkstellig word deur eksperimentele afbinding van die pankreasbuis distaal tot sy samesmelting met die gemene galbuis. 'n Verskeidenheid van selle word vermoedelik by hierdie proses betrek. Dormante stamselle besit die vermoë en/of plastisiteit om 'n aantal vorms van metaplasie te ondergaan om nuwe en/of oortollige endokriene weefsel te vorm wat patologiese en/of eksperimenteel gekompromiseerde weefsel vervang. Die selontwikkelings volgorde wat tydens hierdie proses plaasvind is al vir 'n geruime tyd die middelpunt van 'n meningsverskil. Sommige studies dui daarop dat die in vivo selontwikkelingsvolgorde verskil van in vitro, volgens eksperimentele model en tipe proefdier gebruik. Die doel van die studie was die gebruik van 'n bestaande eksperimentele laboratorium proefdier model om pankreas eiland morfologiese verandering en/ofneogenese of beide in vivo te evalueer. Die oogmerk van die studie was om die omvang en volgorde van veranderings in die endokriene kompartement (neogenese/morfogenese) te bepaal deur gebruik te maak van 'n pankreas buis afbindings (PBA) model wat totale afsnyding van die buis tot gevolg het. PBA's is uitgevoer op ses groepe van 25 volwasse normale Sprague-Dawley (SD) laboratorium rotte (±300g) soos beskryf deur Hultquist en Jonsson (1965). Proefdiere is elke 12 uur geoffer vanaf dag een post-PBA tot dag tien en elke 24 uur daarna tot dag 14 soos beskryf deur Wang, Bouwens, Kloppel (1995) na die toediening van 50 mg/kg 5-Bromo-2-deoksi-uridien intraperitoneaal ('n selprolifererings aanduider) soos beskryf deur Wang et al. (1995). Die pankreas is werwyder, in Bouin se oplossing gefikseer en histologies geprosesseer. Sewe openvolgende seriesnitte (3-6 urn) is alternatiewelik gekleur met H & E, en immunositochemies, soos beskryf deur Guesdon, Terugnek, Avrameas (1979), vir insulien (I), glukagon (G), somatostatien (ST), pankreatiesepolipeptied (PP), neuropeptied tirosien (NPY) en peptied tirosien-tirosien (PYY). BrdU dubbel-immuunkleuring is ingesluit op dae 3,5, 7, 9 en 11 soos beskryf deur Wang et al. (1994). Sellulêre transformasie tussen dae een en 3~ dae is gekenmerk deur gelyktydige en totale uitwissing en/ofmetaplasie van die asinêre kompartement en die verskyning van selle immunorektiefvir I(11.53 ±1.5%), G (1.85 ±0.8%), PP (1.50 ±0.09%), ST (1.96 ±0.24%). Metaplasie was verantwoordelik vir merkbare veranderings in bestaande endokriene weefsel langs In transformasie weg waar eiland insulien kemselle vervang is deur PP- en ST-selle, glukagon buitelaag uitwissing en die toevallige verskyning van alle endokriene seltipes in the inter-eiland interstitium teen dag 3Y2. Dae 4Y2deur 6~ is gekenmerk deur verdere endokrinetoename terwyl dag 7 deur 14 gekenmerk is deur eiland hersamestelling en konsolidering. NPY immunoreaktiwiteit was vanaf dag 4~, met afwisseling, te bespeur terwyl PVV slegs tussen dae 4 en 7 In verskyning gemaak het. . Die resultate suggereer eerstens, PBA induseer die ontwikkeling van oortollige endokriene weefsel op In lukrake wyse versprei deur die ruimte voorheen deur asinêre parenchiem beset. Tweedens, dat die verskyning van insulien deur dié van PP, glukagon en somatostatien met minstens 24-uur voorafgegaan is. Die verhouding, van nuutgevormde endokriene weefsel wat met bestaande eilande assosieer om In aantal baie groot eilande te vorm, moet nog vasgestel word. Sulke strukture mag moontlik afskeidings toegang hê tot die bloedstroom, deur die glomerulusagtige kapillêre netwerk, in die eilandkern teenwoordig terwyl die oorblywende nuutgevormde endokrine weefsel "nuwe" apparte eilande vorm wat wel of gladnie toegang tot die bloedstroom mag hê nie. As gevolgtrekking, indien dit waar is dat volwasse pankreas eilandweefsel wel regenerasie kan ondergaan, dan het dit kliniese implikasie vir die stabilisering van diabetes mellitus. Weefsel verkry uit PBA bevat geen asinêre weefsel nie maar wel merkbare hoeveelhede endokriene weefsel, veral insulin positief. Dit bied dan interessante alternatiewe as skenker weefsel by fetal rot pankreas oorplantings. PBA en/of die oorplanting van pankreasbuis afgebinde weefsel, na in vitro weefsel kultuur, bied moontlikhede vir die behandeling van diabetes mellitus.

Rupture of the anterior cruciate ligament (ACL) of the knee leads to chronic joint instability and reduced range of motion while the long term results are marred by a high prevalence of degenerative joint disease especially osteoarthritis. Bundles of collagen threads have been widely investigated for the repair of torn ACL, but are limited by insufficient tissue ingrowth to repopulate and completely regenerate these grafts. We have developed a novel in vitro method of characterizing fiber-based thread matrices by probing their ability to promote tissue ingrowth from a wound margin as a measure of their ability to promote repopulation and regeneration. This method is useful in the optimization of thread scaffolds, and is sensitive enough to distinguish between subtle variations in biopolymer chemistry and organization. Furthermore, this method was used to characterize the effects of crosslinking on the cell outgrowth and correlated the findings with the mechanical properties of collagen threads. The results suggest that crosslinking is required to achieve sufficient mechanical properties for high stress applications such as ACL replacement, but regardless of technique, crosslinking attenuated the cell outgrowth properties of the threads. To improve the regenerative capacity of these scaffolds, novel fibrin microthread matrices were developed with a similar morphology to collagen threads and sufficient mechanical strength to be incorporated in composite thread scaffold systems. These fibrin microthreads were loaded with FGF-2, a potent mitogen and chemotactic agent that works synergistically with fibrin in regulating cell signaling and gene expression. Increases in fibroblast migration and proliferation in FGF-2-loaded fibrin threads were successfully demonstrated with the concomitant promotion of oriented, aligned, spindle-like fibroblast morphology. These results suggest that fibrin-FGF-2 microthreads have distinct advantages as a biomaterial for the rapid regeneration of injured tissues such as the ACL.