Made available in DSpace on 2014-06-11T19:32:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-17Bitstream added on 2014-06-13T21:05:16Z : No. of bitstreams: 1 souto_ls_dr_botib.pdf: 9317690 bytes, checksum: 3e85c4a8912908b6da4810da133b17a0 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A família Malpighiaceae possui 1.200 espécies e 66 gêneros, com importância para as formações florestais e savânicas do Velho e do Novo Mundo. A origem monofilética da família é incontestável, entretanto seus táxons intrafamiliares ainda são bastante controversos e considerados artificiais por diversos autores. A morfologia floral de Malpighiaceae é bastante homogênea, mas os frutos possuem extrema diversidade, ocorrendo pericarpos deiscentes ou indeiscentes, carnosos ou secos. Embora caracteres morfológicos dos frutos sejam usados na delimitação de táxons dentro de Malpighiaceae, recentes estudos moleculares indicam a ocorrência de caracteres carpológicos homoplásticos. Assim, estudos minuciosos sobre os frutos da família têm grande potencial taxonômico. Além disso, a vascularização floral pode revelar passos evolutivos, anteriores à morfologia floral atual das espécies. Desta forma, a presente proposta tem como objetivos: 1) descrever, ontogeneticamente, a estrutura dos frutos e sementes de quatro espécies de Malpighiaceae, abrangendo os gêneros Janusia, Mascagnia e Tetrapterys; 2) caracterizar a anatomia floral das espécies do item anterior e de Camarea linearifolia, com ênfase em sua vascularização, buscando correlacionar esses aspectos com o significado evolutivo e ecológico das flores de Malpighiaceae; 3) relatar a esporogênese e gametogênese feminina de Janusia occhionii, investigando a provável ocorrência de apomixia. A vascularização floral encontrada nas espécies segue o padrão geral de número de traços vasculares, com exceção de M. cordifolia, onde a sépala aglandular recebe um traço vascular, mas compartilha os traços laterais das sépalas adjacentes, os quais se bifurcam. No ovário, não é emitido traço dorsal de carpelo, ocorrendo um complexo de procâmbio e meristema fundamental; M. cordifolia, possui conação entre... / The family Malpighiaceae includes 1,200 species and 66 genera and has been important for forests and savannas from the Old and the New World. Its monophyletic origin is unquestionable; however, its intrafamilial taxa have still been controversial and considered artificial by several authors. The flower morphology of Malpighiaceae is quite homogeneous, but fruits present extreme diversity, with dehiscent or indehiscent, fleshy or dry pericarps. Although morphological traits of fruits have been used to delimit taxa within Malpighiaceae, recent molecular studies have indicated the occurrence of carpological homoplastic traits. Thus, detailed studies on Malpighiaceae fruits have great taxonomic potential. Furthermore, flower vascularization can reveal evolution steps prior to the current flower morphology of the species. Thus, the present work aimed to: 1) describe, ontogenetically, the structure of fruits and seeds from four Malpighiaceae species, including the genera Janusia, Mascagnia and Tetrapterys; 2) characterize the flower anatomy of such species and Camarea linearifolia, highlighting their vasculature, in order to correlate these aspects with the evolutive and ecological meaning of Malpighiaceae flowers; 3) report female sporogenesis and gametogenesis in Janusia occhionii, investigating the probable occurrence of apomixis. The flower vasculature observed in the species follows the general pattern as to number of vascular traces, except for M. cordifolia, in which the non-glandular sepal receives one vascular trace but shares the lateral traces from adjacent sepals that bifurcate. In the ovary, the dorsal carpel trace is not emitted, occurring a complex of procambium and ground meristem; M. cordifolia presented conated glands from the anterior and adjacent sepals. In T. chamaecerasifolia and Janusia species, the anterior sepal lost their glands probably by reduction... (Complete abstract click electronic access below)

No description available.

Orientador: Denise Maria Trombert Oliveira / Banca: Juliana Marzinek / Banca: Maria das Graças Sajo / Banca: Sandra Maria Carmello-Guerreiro / Banca: Silvia Rodrigues Machado / Resumo: A família Malpighiaceae possui 1.200 espécies e 66 gêneros, com importância para as formações florestais e savânicas do Velho e do Novo Mundo. A origem monofilética da família é incontestável, entretanto seus táxons intrafamiliares ainda são bastante controversos e considerados artificiais por diversos autores. A morfologia floral de Malpighiaceae é bastante homogênea, mas os frutos possuem extrema diversidade, ocorrendo pericarpos deiscentes ou indeiscentes, carnosos ou secos. Embora caracteres morfológicos dos frutos sejam usados na delimitação de táxons dentro de Malpighiaceae, recentes estudos moleculares indicam a ocorrência de caracteres carpológicos homoplásticos. Assim, estudos minuciosos sobre os frutos da família têm grande potencial taxonômico. Além disso, a vascularização floral pode revelar passos evolutivos, anteriores à morfologia floral atual das espécies. Desta forma, a presente proposta tem como objetivos: 1) descrever, ontogeneticamente, a estrutura dos frutos e sementes de quatro espécies de Malpighiaceae, abrangendo os gêneros Janusia, Mascagnia e Tetrapterys; 2) caracterizar a anatomia floral das espécies do item anterior e de Camarea linearifolia, com ênfase em sua vascularização, buscando correlacionar esses aspectos com o significado evolutivo e ecológico das flores de Malpighiaceae; 3) relatar a esporogênese e gametogênese feminina de Janusia occhionii, investigando a provável ocorrência de apomixia. A vascularização floral encontrada nas espécies segue o padrão geral de número de traços vasculares, com exceção de M. cordifolia, onde a sépala aglandular recebe um traço vascular, mas compartilha os traços laterais das sépalas adjacentes, os quais se bifurcam. No ovário, não é emitido traço dorsal de carpelo, ocorrendo um complexo de procâmbio e meristema fundamental; M. cordifolia, possui conação entre... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The family Malpighiaceae includes 1,200 species and 66 genera and has been important for forests and savannas from the Old and the New World. Its monophyletic origin is unquestionable; however, its intrafamilial taxa have still been controversial and considered artificial by several authors. The flower morphology of Malpighiaceae is quite homogeneous, but fruits present extreme diversity, with dehiscent or indehiscent, fleshy or dry pericarps. Although morphological traits of fruits have been used to delimit taxa within Malpighiaceae, recent molecular studies have indicated the occurrence of carpological homoplastic traits. Thus, detailed studies on Malpighiaceae fruits have great taxonomic potential. Furthermore, flower vascularization can reveal evolution steps prior to the current flower morphology of the species. Thus, the present work aimed to: 1) describe, ontogenetically, the structure of fruits and seeds from four Malpighiaceae species, including the genera Janusia, Mascagnia and Tetrapterys; 2) characterize the flower anatomy of such species and Camarea linearifolia, highlighting their vasculature, in order to correlate these aspects with the evolutive and ecological meaning of Malpighiaceae flowers; 3) report female sporogenesis and gametogenesis in Janusia occhionii, investigating the probable occurrence of apomixis. The flower vasculature observed in the species follows the general pattern as to number of vascular traces, except for M. cordifolia, in which the non-glandular sepal receives one vascular trace but shares the lateral traces from adjacent sepals that bifurcate. In the ovary, the dorsal carpel trace is not emitted, occurring a complex of procambium and ground meristem; M. cordifolia presented conated glands from the anterior and adjacent sepals. In T. chamaecerasifolia and Janusia species, the anterior sepal lost their glands probably by reduction... (Complete abstract click electronic access below) / Doutor

Spinal Muscular Atrophy (SMA) is an autosomal, recessive form of childhood motor neuron disease and the most common genetic cause of infant mortality in the western world. SMA displays the characteristic hallmarks of a motor neuron disease, including loss of motor neurons in the spinal cord and atrophy of skeletal muscles. However, mounting evidence suggests that multiple tissues and body systems, beyond the neuromuscular system, are affected in SMA. Previous studies have highlighted alterations in the vascular system in both SMA patients and in a variety of mouse models of the disease, reporting alterations in vessel structure and perfusion abnormalities in peripheral tissues. In this project a detailed morphological investigation of the capillary beds of skeletal muscle and the spinal cord, two of the key pathological tissues in SMA was undertaken. This work was conducted in the Smn-/-;SMN2, Smn-/-;SMN2tg/+ and Smn-/-;SMN2;Δ7 mouse models of SMA. Significant alterations in the form and extent of the skeletal muscle and spinal cord capillary bed in SMA mice were identified, the most striking of which being a reduction in capillary density in SMA tissue when compared to control littermate tissue. In skeletal muscle, this reduction in capillary density was found to be a postnatal phenomenon, which occurred independently of denervation, in a variety of phenotypically distinct muscles and in all three SMA mouse models investigated. In the spinal cord, the capillary defect was seen to develop in a similar postnatal pattern to that observed in skeletal muscle. Importantly, a reduction in capillary density was observed in the ventral horn of the spinal cord, which houses motor neuron cell bodies, a known pathological target in SMA. These motor neurons were seen to be surrounded by fewer capillaries than their control counterparts. Using an injectable marker of hypoxia, it was determined that the cells of the ventral horn of SMA spinal cords are hypoxic. This suggests that the capillary defect identified has a functional impact on the tissues it is observed in. Having established the presence of capillary defect in SMA tissue, the effect of potential SMA therapeutics on the capillary defect was then investigated. The effect of HDAC inhibitors, which have been successfully shown to increase the levels of the disease causing Smn protein, was investigated. Treatment with the HDAC inhibitor SAHA was found to ameliorate the capillary defect, significantly improving capillary density in SMA skeletal muscle. This implies that the capillary defect is related to Smn levels in tissue and is amenable to therapeutics which increase Smn levels. Having characterised the capillary defect in SMA tissues in detail, a selection of tools were then used to investigate the underlying mechanisms resulting in the defect. First, using primary cell cultures, the growth and morphology of the key cellular component of capillaries, the endothelial cell, was examined. While displaying reduced levels of the Smn protein, endothelial cells isolated from SMA tissues showed no difference in growth rate, morphology or endothelial cell marker expression when compared to endothelial cells isolated from control tissue. This suggests that the defects seen in SMA capillary beds are not the result of defects in the structure and growth of endothelial cells. Second, retinas from SMA mice were found to exhibit similar capillary defects to those observed in SMA skeletal muscle and spinal cord. Given the entirely postnatal development of the retinal capillary network, the retina was identified as a useful experimental preparation for the further investigation of the mechanisms underlying the capillary defect in SMA. In summary, this work highlights the incidence and importance of capillary defects in mouse models of spinal muscular atrophy.

Increasing age is the single biggest independent risk factor for cardiovascular disease, which is in turn the leading cause of morbidity and mortality worldwide. Ageing is associated with hypertension and metabolic changes which all increase the risk of the development of cardiovascular disease. In young, healthy individuals, perivascular adipose tissue (PVAT) secretes factors that can influence vascular contractility, exerting a net anti-contractile effect against numerous vasoconstrictors including the thromboxane A2 mimetic U46619 and α1-adrenoceptor phenylephrine. Whilst it is known that dysfunction in PVAT can contribute to obesity-related hypertension, little is known whether similar dysfunction occurs with ageing. In young Wistar rats, wire myography and pharmacological studies showed that the anti-contractile effect of PVAT in the presence of U46619 is dependent on both PVAT-derived nitric oxide and prostaglandins, whereas the anti-contractile effect in the presence of phenylephrine is nitric oxide independent. This finding was supported by Western blot experiments that showed increased phosphorylation of endothelial nitric oxide synthase (eNOS) in PVAT following U46619 incubation, but not phenylephrine. In the Wistar rat model of ageing used, wire myograph studies revealed that the PVAT anti-contractile effect in the presence of phenylephrine is preserved at 24 months of age, but in in the presence of U46619 is lost. Furthermore PVAT from aged animals had a deleterious effect on endothelial function, suggesting changes in its secreted factors. These changes are accompanied by alterations in the expression and activation of key enzymes in the nitric oxide synthesis pathway within the PVAT as measured by Western blot, as well as alterations in cardiometabolic phenotype including hypertension, hyperglycaemia and insulin resistance. Taken together these findings suggest that previously unidentified age-related PVAT dysfunction may contribute to age-related hypertension and thus may provide a potential therapeutic target for future study.

There are a number of pressing issues that the creation of a biomimetic liver culture may be able to solve including catching hepatic mal interactions that are currently missed in preclinical drug screening and offering an alternative solution in the shortage of organs for liver transplant. There are multiple hepatic models that have been created to overcome these issues. However, of the many considerations that need to be taken in the creation of a biomimetic liver model, many fail to capture the functional zone-patterning that is found in vivo. Here is detailed the creation of a hepatic assembloid model that incorporates zone-specific human pluripotent stem cell derived hepatocytes for the recapitulation of zone-patterning in the liver tissues. Use of our lab’s z-wire plate and PGS z-wire scaffold allows for the formation of elongated 3D tissues that resembles the overall morphology of the liver acinus and facilitate the spontaneous development of an aligned vascular-like network. Sustained hepatocyte-specific function in these tissues are promising indicators for application of the hepatic models in drug screening, disease modelling, and regenerative medicine. / Thesis / Master of Applied Science (MASc)

No description available.

No description available.

Poor oxygenation of solid tumours has been linked with resistance to chemo- and radio-therapy and poor patient outcomes. Measuring the functional status of the tumour vasculature, including blood flow fluctuations and changes in oxygenation is important in cancer staging and therapy monitoring. A robust method is needed for clinical non-invasive measurement of the oxygen supply and demand in tumours. Current clinically approved imaging modalities suffer high cost, long procedure times and limited spatio-temporal resolution. Optoacoustic tomography (OT) is an emerging clinical imaging modality that can provide static images of endogenous haemoglobin concentration and oxygenation. In this work, an integrated framework for quantitative analysis of functional imaging using OT is developed and applied in vivo with preclinical cancer models. Oxygen Enhanced (OE)-OT is established here to provide insight into tumour vascular function and oxygen availability in the tissue. Tracking oxygenation dynamics using OE-OT reveals significant differences between two prostate cancer models in nude mice with markedly different vascular function (PC3 & LNCaP), which appear identical in static OT. OE-OT metrics are shown to be highly repeatable and correlate directly on a per-tumour basis to tumour vascular maturity, hypoxia and necrosis, assessed ex vivo. Dynamic Contrast Enhanced (DCE) OT demonstrates the relationship between OE-OT response and tumour perfusion in vivo. Finally, the possibility of using OT data acquired at longer wavelengths to report on tumour water and lipid content is investigated, with a view to future providing intrinsically co-registered imaging of tumour oxygenation and cellular necrosis. These findings indicate that OE-OT holds potential for application in prostate cancer patients, to improve delineation of aggressive and indolent disease, while combined with DCE-OT, it may offer significant advantage for localised imaging of tumour response to vascular targeted therapies. Further work is needed to establish whether OT can provide a new method to detect tumour necrosis in vivo.

Migraine is a complex neurological disorder that affects approximately 38 million Americans. For over 25 years, the neuropeptide calcitonin gene-related peptide (CGRP) has been implicated in the pathogenesis of migraine. In fact, several pharmaceutical companies are tailoring treatments to antagonize CGRP actions. However, due to the complexity of migraine, exactly how and where CGRP acts to contribute to migraine have remained controversial: whereas several studies suggest that CGRP acts in the central nervous system (CNS) in this context, others have indicated a role in the periphery. Central nervous system sites of action include the trigeminal nucleus and several higher brain regions, and peripheral sites include the vasculature and dural mast cells in the meninges. Among the sites of CGRP action, the trigeminal nerve, which is the major somatosensory structure of the face, is of particular interest because it bridges the CNS and the periphery. Migraine is generally thought to involve abnormal signaling in the trigeminovascular system, and about 50% of trigeminal neurons have CGRP immunoreactivity. Although the notion that CGRP has a central site of action in relation to migraine had gained ground over the past decade, the recent discovery that monoclonal antibodies against CGRP can prevent migraine attacks has resurrected the possibility that a peripheral site of action is involved as well. Clarification of the sites of CGRP action in migraine will be crucial to developing an understanding of mechanisms that underlie migraine so that future treatments can be rationally designed. One diagnostic criterion for migraine is photophobia, a painful and often debilitating response to non-noxious levels of light. Our laboratory previously developed a preclinical model of migraine in which the light-aversive behavior of mice is used as a surrogate of photophobia. Specifically, mice were sensitized to CGRP by introducing a nestin/hRAMP1 transgene. In these mice versus control littermates, light aversion in response to central (intracerebroventricular, ICV) injection of CGRP was enhanced in dim light. In wild-type mice, CGRP (ICV) also elicited aversion to very bright light; this did not occur in vehicle-treated mice. Additionally, I have shown that CGRP injected peripherally (intraperitoneal, IP) can induce significant light aversion in wild-type mice. I have begun to identify the sites of action outside of the central nervous system, using four lines of transgenic mice with different patterns of overexpression of CGRP receptors: global hRAMP1 mice (expression in all tissues), nestin/hRAMP1 mice (expression only in nervous tissue), tagln/hRAMP1 (expression only in smooth muscle cells), and tek2/hRAMP1 (expression in endothelial cells). As predicted, in the global hRAMP mice light aversion, in response, to IP-injected CGRP was enhanced. However, in nestin/hRAMP1 mice, only ICV-injected, and not IP-injected, CGRP induced enhanced light aversion. This finding suggests that peripheral CGRP activates neural pathways involved in light aversion, but by an indirect mechanism. To determine where in the periphery CGRP is acting, a pharmacological and genetic approach was taken. Since CGRP is one of the most potent vasodilators in the body, it is well positioned to have vascular effects that induce light aversive behavior. This hypothesis was based on findings that 1) intravenous administration of CGRP in human subjects can cause migraine pain, and 2) perivascular CGRP can sensitize the trigeminal nerve, which could alter synaptic transmission to the central nervous system and 3) CGRP monoclonal antibodies are effective in clinical trial and likely do not cross the blood brain barrier. Thus, there is a mechanism by which CGRP in the periphery can sensitize the trigeminal nerve and alter sensory perception, leading to photophobia. The role of the vasculature in migraine, specifically vasodilation, has been controversial and now the consensus is that it is neither necessary nor sufficient. First, I wanted to test the role of vasodilation in this model. I pharmacologically inhibited CGRP-induced vasodilation using two vasoconstrictors, phenylephrine and endothelin-1. Blocking CGRP-induced vasodilation partially attenuates the light aversive response. Moreover, mice that overexpress the CGRP receptor in smooth muscle, but not endothelial, cells exhibit enhanced light aversion indicating a role for vascular actions of CGRP in this preclinical model of migraine. These results present clear evidence that CGRP has actions on the vasculature to induce light aversion. Additionally, the inability of blocking vasodilation to completely rescue the light aversion suggests that the vasculature may not be the only peripheral target of CGRP in migraine pathophysiology. This work improves the understanding of peripheral CGRP actions in migraine and raises awareness that contribution of the vasculature in migraine should not be ignored. The identification of sites of CGRP action in regions inside and outside of the CNS could lead to improved and more successful therapeutics for migraine.