No description available.

Thesis (M. S.)--Bioengineering, Georgia Institute of Technology, 2010. / Committee Chair: Ku, David; Committee Member: Gleason, Rudolph; Committee Member: Milner, Ross. Part of the SMARTech Electronic Thesis and Dissertation Collection.

No description available.

Background. Growth-arrest specific 6 (gas6) is a novel vitamin-K dependent protein whose role in venous thromboembolism was recently characterized in murine models. Gas6 is suggested to be a prothrombotic protein capable of mediating thrombus stability. However, the association between gas6 and venous thromboembolism has yet to be elucidated in humans. The present work aims to delineate the existence of such an association in humans and propose a mechanism by which gas6 expression is related to venous thromboembolic disease. / Methods. To analyze the association between gas6 and venous thromboembolism, a highly specific ELISA method was used to measure plasma gas6 levels in 306 patients with a history of deep-vein thrombosis (DVT) and 89 control volunteers. Medication history, comorbid conditions and DVT characteristics were documented for the purposes of statistical analyses. Median gas6 levels were compared between the subgroups, and prevalence rate ratios were calculated. Human umbilical vein endothelial cells were used to measure the effect of gas6 treatment on the expression of various mediators of coagulation. Murine thrombosis models were developed to serve as in vivo models for thrombosis. / Results. The median levels of gas6 were 28.21 ng/ml in patients compared to 26.15 ng/ml in controls (p=0.01). After adjustment for age, sex, comorbidity and medications, DVT patients had a PRR of 2.5 (95% CI 1.36 to 4.61, p=0.003) compared with controls. Within the DVT subgroup, median gas6 levels were significantly higher in those with cancer-associated (vs. unprovoked or secondary) DVT (p<0.001) and in those with more extensive DVT (p=0.037), while levels were significantly lower in those taking warfarin (vs. no warfarin) (p=0.03). Preliminary results with endothelial cell cultures are inconclusive with regards to the effect of gas6 on endothelium derived mediators of coagulation. / Conclusions. Elevated plasma gas6 is associated with venous thromboembolism. The etiology of the clot influences detected levels of gas6, with the highest levels seen in cancer-patients. Furthermore, increasing clot burden correlates with elevated levels of gas6. A mechanistic explanation for how gas6 modulates this association is in its preliminary stages, and is worth pursuing.

This project sought to develop a system that facilitated the visual inspection of venous leg ulcers by establishing a selection of reliable parameters. The project had three principal aims: to develop a reliable method for capturing the colours exhibited by a venous leg ulcer; to establish a colour range that experienced clinicians believed represented wet necrotic tissue and erythema; and to develop software that highlighted the two manifestations in digital photographs. The project method was divided into three phases. The first phase examined images taken from twenty-two patients over forty-seven episodes of care. During each episode three sequential images were captured using a frame to control for orientation, magnification and lighting resulting in a bank of 141 images. The reliability of the system to accurately capture colour was then determined by examining the amount of colour variation recorded across the set of three images taken at each episode. The second phase asked eight experienced clinicians to examine a set of twenty photographs taken from the bank established in phase one. On each photograph the clinicians were asked to identify areas of wet necrotic tissue or erythema and outline the areas with a colour pen supplied for each manifestation. A colour range was then constructed to represent each manifestation by measuring the range, mean and standard deviation of pixels that were located within the outlined areas. The third phase developed a computerised system that used the colour range established in phase two to highlight areas of a digital image that represented either erythema or wet necrotic tissue. The validity of the highlighted areas was then tested by asking experienced clinicians to identify their level of agreement with the areas selected by the computer system. Analysis of the results from phase one indicated that the system used to record images at each episode of care provided a reliable method for maintaining consistent orientation, magnification and replication of colour. Results from phase two yielded a two distinct colour representation of erythema and wet necrotic tissue. Erythema ranged from 3600 to 3780 of hue with a mean of 369.210, and wet necrotic tissue ranged from 3670 to 3900 of hue with a mean of 387.730. Results from phase three indicated that whilst clearly delineated areas of erythema and wet necrotic tissue were visible, the validity of the representations was varied. 50 per cent of experienced clinicians agreed with the areas selected as erythema and 60 per cent agreed with the areas selected by the computer system as wet necrotic tissue. The system developed during this study for recording images of venous leg ulcers provides a reliable method for further research into the visual progression of this disease. However, the colour range identified as being representative of erythema or wet necrotic tissue and the computer system developed to highlight such areas in a digital image, requires further investigation before it is applicable to the clinical setting. The findings do however provide further insights into the varied nature of expert opinion when judging the colour of venous leg ulceration.

Records of all neurosurgical inpatients admitted to Royal North Shore Hospital since 1976 have been prospectively kept in a relational database. Demographic details, diagnoses, operations and complications have been entered continuously since 1982 by the author of this study. Complications are monitored at monthly review meetings attended by medical staff. The recurrence of deep vein thrombosis (DVT) and pulmonary embolism (PE) at these meetings, despite continual improvements in patient care, prompted this study. It aims to use the database to study changes in the incidence of DVT and PE over the previous twenty years; to find what database variables predict these complications; and whether use of mechanical and pharmacological agents has had an impact on DVT and PE rate. Univariate analysis of the incidence of DVT and PE by age, sex, length of stay (LOS), admission month, diagnosis, operation and surgeon over time was run. Any significant variables were then analysed by multivariate logistic regression. The DVT rate was low by world standards, but rose from 0.6% in 1979-83 to 1.2% in 1984-88, then rose exponentially to 3.60% in 1994-98 with a significantly increasing trend over the twenty years (c2 MH =114.20, with IDF, P<0.001). PE rate doubled significantly over the twenty years from 0.6% to 1.2% (c2 MH =17.94 with 1DF, P<0.001). Age, LOS, diagnosis, operation and surgeon were significant predictors of DVT and PE. After adjustment for LOS, time period and age, vascular surgery was found to be the strongest predictor of DVT (OR=2.82, 95% CI: 2.08-3.82, c2 =43.91, P<0.01). Vascular diagnosis was the strongest diagnosis predictor. No effect of sex or month of admission was shown. After adjustment for LOS, time period and age, spinal fusion was the strongest predictor of PE (OR=4.04, 95% CI: 1.81-9.03). Anterior communicating artery aneurysm was the diagnosis most highly associated with PE. The rise in DVT rate may be due to increased complexity of surgical and nursing management, and some screening of patients with the introduction of duplex scanning. The doubling of PE rate is unexplained. The risk of brain or spinal cord haemorrhage makes prophylactic anticoagulation a difficult choice. This study reveals groupings which can be used to determine appropriate prophylaxis. Use of mechanical and pharmaceutical agents is not recorded consistently in the database, but it is known approximately when they were introduced. No impact on the rate of DVT and PE can be demonstrated by these agents. More vigilant and widespread use of mechanical prophylaxis might be just as effective in controlling DVT and PE.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Thesis--Umeå University, Sweden. / Also published as Umeå University Medical dissertations, ISSN 0346-6612 ; new ser. no. 75.

Orientador: Hamilton Almeida Rollo / Banca: Luciana Patrícia Fernandes Abbade / Banca: Amélia Cristina Seidel / Banca: Regina Moura / Banca: Domingos de Morais Filho / Resumo: A doença venosa crônica (DVC) é uma doença comum com conseqüênciassócio-econômicas importantes. O refluxo é uma das principais causas da OVC. Detectar e quantificar o refluxo são medidas importantes no diagnóstico de insuficiênciavenosa crônica. A avaliação quantitativa da DVC pode ser realizada por meiode métodos invasivos e não invasivos. Os métodos não invasivos, quantitativos, 810: fotopletismografia (FPG), pletismografia a ar e o mapeamento dúplex. O MO, rão-ouro, permite a detecção e quantificação acurada do refluxo em veias individuais, pela medida da duração do refluxo ou tempo de fechamento da válvula, além de proporcionar informações anatõmicas e funcionais relevantes para direcionar o tratamento de veias varicosas. Nos pacientes com varizes primárias dos membros -'inferioresa veia safena magna (VSM) é freqüentemente acometida, especialmente por refluxo na junção safeno-femoral (JSF), por insuficiência da válvula ostial. A avaliaçãoda VSM é importante porque a sua preservação traz vantagens, pois a mesmatem sido utilizada como substituto arterial em doenças degenerativas, como a doença arterial obstrutiva crônica dos membros inferiores, na revascularização miocárdica e nos traumas vasculares de extremidades. Estudos já publicados mostraram que o MO permite avaliar as alterações morfológicas e funcionais da V5M e quantificá-las, porém dúvidas permaneceram em relação... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The chronic venous disease (CVD) is a common disease with socio-economic consequences. Reflux is one of the main causes of CVD. Detecting and quantifying the reflux are important steps in the diagnosis of chronic venous insufficiency. The quantitative evaluation of CVD may be performed by means of invasive and non-invasive methods. Non-invasive quantitative methods are: photoplethysmography (FPG), air plethysmography and duplex scan. The DS, gold standard, allows the detection and quantification accurate measurement of the vein reflux individual, by the measure of length of reflux or time of valve closure, in addition to providing functional and relevant anatomical information to guide the treatment of varicose veins. In patients with primary varicose veins of the lower limbs the great saphenous vein (GSV) is frequently affected, especially by reflux in the saphenofemoral junction (SFJ), because of the failure of the ostial valve. The evaluation of the GSV is important because its preservation brings advantages so that it has been used as a replacing arterial in degenerative diseases such as chronic obstructive arterial disease of the lower limbs, in myocardial revascularization and in vascular trauma of the extremities. Studies already published showed that the DS makes it possible to evaluate the morphological and functional alterations of the GSV and quantifies them, but doubts remained in relation to the value of these parameters... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-06-11T19:26:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-28Bitstream added on 2014-06-13T19:13:52Z : No. of bitstreams: 1 oliveira_mg_me_botfm.pdf: 765631 bytes, checksum: 770d8b935d3cfcc2b0617ece4f83fe51 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As úlceras venosas são impactantes e representam um grande desafio médico devido ao entrelaçamento de comorbidades e causas multifatoriais, sendo de suma importância o surgimento de inovações tecnológicas na abordagem terapêutica que sejam acessíveis aos seus portadores. Diante dessa realidade, este trabalho se propôs a abordar as úlceras venosas comparando um produto existente no mercado, Hidrocolóide (HC), com uma proposta in house, o Gel de Plaquetas (GP), através da diminuição da área, avaliação descritiva da vascularização e queixas referidas. Participaram do estudo 17 pacientes, perfazendo um total de 22 úlceras venosas que foram acompanhados durante 90 dias, utilizando um dos produtos citados, de acordo com o randomização, em associação com o uso de faixas elásticas. A distribuição do grupo, segundo a randomização foi de 13 lesões no grupo de hidrocolóide e 9 no grupo de gel de plaquetas. A média percentual de redução das áreas das feridas foi de 57,78% para hidrocolóide e de 53,45% para gel de plaquetas, não apresentando diferenças estatisticamente significativas. O desempenho dos produtos estudados apresentaram grande similaridade no percentual de redução de área, o que indica que é preciso um estudo amostral maior para evidenciar superioridade de um produto sobre o outro. Porém quando comparados, quanto ao menor tempo de acompanhamento (D15), o gel de plaquetas apresentou melhor desempenho, com redução maior do que o hidrocolóide em tempo reduzido semelhante. A análise histológica no momento pré e pós tratamento sugere que o GP atua de forma a estimular a regeneração dos tecidos (estroma coeso) e de forma mais definitiva (distribuição dos vasos difusa na derme reticular). O aspecto do fechamento da lesão é mais consistente quando comparado com os pacientes que usaram HC onde se observou a formação de uma fina epiderme frágil... / Venous ulcers are striking and represent a major challenge due to the commingling of medical comorbidities and multifactorial causes, with the emergence of great importance to technological innovations in therapeutic approaches that are accessible to their patients. Given this reality, this study proposes to address venous ulcers comparing a product on the market, hydrocolloid (HC) with a proposed in-house, the Platelet Gel (GP), by decreasing the area and descriptive evaluation of vascularization complaints referred. The study included 17 patients, a total of 22 venous ulcers who were followed for 90 days, using one of the products listed, according to the randomization, in association with the use of compression elastic. The distribution of the group, according to randomization was 13 injuries in the hydrocolloid group and 9 in the group of platelet gel. The average percentage reduction of wound areas was 57.78% for hydrocolloid and 53.45% for platelet gel, showing no statistically significant differences. The performance of the products studied showed great similarity in the percentage of area reduction, which indicates that it is necessary to study a larger sample to demonstrate the superiority of one product over another. But when compared, for the shortest time of follow-up (D15), the platelet gel performed better, with greater reductions than the hydrocolloid in a short time like that. Histological analysis in the D0 and D90 of the treatment suggests that the GP acts to stimulate the regeneration of tissues (stroma together) and more definite form (diffuse distribution of vessels in the reticular dermis). The appearance of the closure of the injury is more consistent when compared with patients who used HC we observed the formation of a thin skin, fragile, observed in histological sections showed that a distribution of vessels in the papillary dermis. Histological sections confirmed... (Complete abstract click electronic access below)