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The Human Spiral GanglionTylstedt, Sven January 2003 (has links)
<p>Our knowledge of the fine structure of the Human Spiral Ganglion (HSG) is still inadequate and new treatment techniques for deafness using electric stimulation, call for further information and studies on the neuronal elements of the human cochlea. This thesis presents results of analyses of human cochlear tissue and specimens obtained during neurosurgical transpetrosal removal of life-threatening meningeomas. The use of surgical biopsies produced a well-preserved material suitable for ultrastructural and immunohistochemical studies on the human inner ear. The SG was studied with respect to fine structure, using TEM technique and the immunostaining pattern of synaptophysin, which is an integral membrane protein of neuronal synaptic vesicles. The immunostaining patterns of the tight junctional protein ZO-1 and the gap junctional proteins Cx26 and Cx43 in the human cochlea were also studied. The ultrastructural morphology revealed an absence of myelination pattern in the HSG, thus differing from that in other species. Furthermore, formation of structural units as well as signs of neural interaction between the type 1 neurons could be observed. Type 1 cells were tightly packed in clusters, sharing the ensheathment of Schwann cells. The cells frequently made direct physical contact in Schwann cell gaps in which membrane specializations appeared. These specializations consisted of symmetrically or asymmetrically distributed filamentous densities along the apposed cell membranes. The same structures were also present between individual unmyelinated nerve fibres and the type 1 cells. Synapses were observed on the type 2 neurons, with nerve fibres originating from the intraganglionic spiral bundle. Such synapses, though rare, were also observed on the type 1 cells. The ultrastructural findings were confirmed by the synaptophysin study. A 3-D model of a Schwann cell gap between two type 1 cells was constructed, describing the distribution pattern of membrane specializations. In the immunohistochemical studies on the human cochlea, ZO-1 was expressed in tissues lining scala media, thus contributing to the formation of a closed compartment system, important for the maintenance of the specific ionic composition of the endolymph. Protein Cx26 could be identified in non-sensory epithelial cells of the organ of Corti, in connective tissue cells of the spiral ligament and spiral limbus, as well as in the basal and intermediate cell layers of stria vascularis. Cx26 in this region may be involved in the recycling of potassium. Protein Cx43 stained weakly in the spiral ligament, but intense staining in the SG may indicate that gap junctions exist between these neurons. A different functional role for the HSG can be assumed from the morphological characteristics and the signs of a neural interaction between the SG cells. This might be relevant for neural processing mechanisms in speech coding and could have implications for cochlear implant techniques.</p>
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The Human Spiral GanglionTylstedt, Sven January 2003 (has links)
Our knowledge of the fine structure of the Human Spiral Ganglion (HSG) is still inadequate and new treatment techniques for deafness using electric stimulation, call for further information and studies on the neuronal elements of the human cochlea. This thesis presents results of analyses of human cochlear tissue and specimens obtained during neurosurgical transpetrosal removal of life-threatening meningeomas. The use of surgical biopsies produced a well-preserved material suitable for ultrastructural and immunohistochemical studies on the human inner ear. The SG was studied with respect to fine structure, using TEM technique and the immunostaining pattern of synaptophysin, which is an integral membrane protein of neuronal synaptic vesicles. The immunostaining patterns of the tight junctional protein ZO-1 and the gap junctional proteins Cx26 and Cx43 in the human cochlea were also studied. The ultrastructural morphology revealed an absence of myelination pattern in the HSG, thus differing from that in other species. Furthermore, formation of structural units as well as signs of neural interaction between the type 1 neurons could be observed. Type 1 cells were tightly packed in clusters, sharing the ensheathment of Schwann cells. The cells frequently made direct physical contact in Schwann cell gaps in which membrane specializations appeared. These specializations consisted of symmetrically or asymmetrically distributed filamentous densities along the apposed cell membranes. The same structures were also present between individual unmyelinated nerve fibres and the type 1 cells. Synapses were observed on the type 2 neurons, with nerve fibres originating from the intraganglionic spiral bundle. Such synapses, though rare, were also observed on the type 1 cells. The ultrastructural findings were confirmed by the synaptophysin study. A 3-D model of a Schwann cell gap between two type 1 cells was constructed, describing the distribution pattern of membrane specializations. In the immunohistochemical studies on the human cochlea, ZO-1 was expressed in tissues lining scala media, thus contributing to the formation of a closed compartment system, important for the maintenance of the specific ionic composition of the endolymph. Protein Cx26 could be identified in non-sensory epithelial cells of the organ of Corti, in connective tissue cells of the spiral ligament and spiral limbus, as well as in the basal and intermediate cell layers of stria vascularis. Cx26 in this region may be involved in the recycling of potassium. Protein Cx43 stained weakly in the spiral ligament, but intense staining in the SG may indicate that gap junctions exist between these neurons. A different functional role for the HSG can be assumed from the morphological characteristics and the signs of a neural interaction between the SG cells. This might be relevant for neural processing mechanisms in speech coding and could have implications for cochlear implant techniques.
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Ácido acetilsalicílico como estratégia neuroprotetora em ratos submetidos à hiperhomocisteinemia leve : avaliações neuroquímicas e morfológicasMoreira, Daniella de Souza January 2017 (has links)
A homocisteína é um aminoácido sulfurado derivado do metabolismo da metionina. Quando os níveis plasmáticos de homocisteína ultrapassam 10-15 μM, tem-se uma condição conhecida como hiperhomocisteinemia, a qual pode ser classificada em leve (>10 μM), moderada (>30 μM) ou severa (>100 μM). A hiperhomocisteinemia leve não tem origem genética, sendo considerada um fator de risco para o desenvolvimento de doenças neurodegenerativas e vasculares, incluindo isquemia cerebral e cardíaca. Nosso grupo de pesquisa desenvolveu um modelo químico induzido de hiperhomocisteinemia leve crônica em ratos adultos jovens e, usando esse modelo foi mostrado que existe associação entre essa condição e alterações em parâmetros de inflamação e estresse oxidativo/nitrativo em tecido cerebral. O objetivo do presente estudo foi avaliar se o ácido acetilsalicílico tem papel neuroprotetor no efeito da homocisteína sobre os níveis de interleucinas IL-1β e IL-6, atividade e imunoconteúdo da acetilcolinesterase, biodisponibilidade de óxido nítrico, atividade e imunoconteúdo das enzimas antioxidantes superóxido dismutase e catalase, conteúdo de sulfidrilas e índice de dano ao DNA. Também realizamos análise morfológica por microscopia eletrônica de transmissão em córtex cerebral de ratos submetidos ao modelo. Ratos Wistar receberam homocisteína (0,03 μmol/g de peso corporal) por injeções subcutâneas duas vezes ao dia e ácido acetilsalicílico (25 mg/Kg de peso corporal) por injeções intraperitoneais uma vez ao dia, do dia 30 ao 60º dia pós-parto Ratos controles receberam o mesmo volume da solução veículo. Doze horas após a última injeção, alguns animais foram decapitados para posteriores análises bioquímicas, e outros animais foram perfundidos para posterior análise morfológica. Os resultados mostraram que os ratos submetidos à hiperhomocisteinemia leve apresentaram aumento significativo dos níveis de IL-1β, IL-6 e da atividade da acetilcolinesterase, bem como níveis reduzidos de nitritos. A homocisteína também diminuiu as atividades da superóxido dismutase e catalase, bem como o imunoconteúdo da catalase. Danos às proteínas e DNA, assim como alterações ultraestruturais também foram observadas no córtex cerebral dos animais hiperhomocisteinêmicos. O ácido acetilsalicílico preveniu totalmente o efeito da homocisteína sobre a atividade da acetilcolinesterase, atividade e imunoconteúdo da catalase, e alterações ultraestruturais. As alterações nos níveis de IL-1β, atividade de superóxido dismutase, conteúdo de sulfidrilas e dano ao DNA foram parcialmente prevenidas pelo ácido acetilsalicílico. Nossos achados mostraram que o modelo induzido quimicamente de hiperhomocisteinemia leve alterou alguns parâmetros inflamatórios, oxidativos/nitrativos e morfológicos. Nossos resultados também sugerem que o ácido acetilsalicílico desempenha um papel neuroprotetor nas condições apresentadas, pois preveniu a maior parte dessas alterações. Porém, a administração crônica do ácido acetilsalícico também apresentou efeito per se significativo de dano ao DNA, o qual deve ser melhor elucidado em estudos posteriores. / Homocysteine is a sulfur amino acid derived from methionine metabolism. When plasma homocysteine levels exceed 10-15 μM, there is a condition known as hyperhomocysteinemia, which can be classified as mild (>10 μM), moderate (>30 μM), or severe (>100 μM). Mild hyperhomocysteinemia does not have genetic origin and it is considered a risk factor for the development of neurodegenerative and vascular diseases, including cerebral and cardiac ischemia. Our research group has developed an induced chemical model of chronic mild hyperhomocysteinemia in young adult rats and using this model, it has been shown an association between this condition and changes in parameters of inflammation and oxidative/nitrative stress in brain tissue. The objective of the present study was to evaluate if acetylsalicylic acid has a neuroprotective role in the effect of homocysteine on IL-1β and IL-6 interleukin levels, acetylcholinesterase activity and immunocontent, nitric oxide bioavailability, activity and immunocontent of antioxidant enzymes superoxide dismutase and catalase, sulfhydryl content and DNA damage index. We also performed morphological analysis by transmission electron microscopy in the cerebral cortex of rats submitted to the model. Wistar male rats received homocysteine (0.03 μmol/g of body weight) by subcutaneous injections twice a day and acetylsalicylic acid (25 mg/Kg of body weight) by intraperitoneal injections once a day from the 30th to the 60th postpartum day Control rats received the same volume of vehicle solution. Twelve hours after the last injection, some animals were decapitated for subsequent biochemical analyzes, and other animals were perfused for subsequent morphological analysis. The results showed that rats submitted to mild hyperhomocysteinemia significantly increased levels of IL-1β, IL-6, acetylcholinesterase activity and reduced nitrite levels. Homocysteine also decreased the activities of superoxide dismutase and catalase, as well as catalase's immunocontent. Damage to proteins and DNA as well as ultrastructural changes were also observed in the cerebral cortex of hyperhomocysteinemic animals. Acetylsalicylic acid totally prevented the effect of homocysteine on acetylcholinesterase activity, catalase activity and immunocontent, and ultrastructural changes. Alterations in IL-1β levels, superoxide dismutase activity, sulfhydryl content and DNA damage were partially prevented by acetylsalicylic acid. Our findings showed that the chemically induced model of mild hyperhomocysteinemia altered some inflammatory, oxidative/nitrative and morphological parameters. Our results also suggest that acetylsalicylic acid plays a neuroprotective role in the conditions presented, as it prevented most of these changes. However, chronic administration of acetylsalicylic acid also had a significant effect of DNA damage, which should be better elucidated in later studies.
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Avaliação seminal e testicular de cães submetidos à administração de cisplatina /Castro, Michele Garcia Medeiros Teotônio de. January 2010 (has links)
Orientador: Wilter Ricardo Russiano Vicente / Banca: Márcia Rita Fernandes Machado / Banca: Andrigo Barboza De Nardi / Resumo: A correta orientação do Médico Veterinário, aos proprietários de cães, usados com finalidades reprodutivas, submetidas à quimioterapia com cisplatina, é importante na medida que este agente citostático age nas células em constante divisão, podendo ser citotóxico para as células germinativas testiculares. O objetivo desse trabalho foi avaliar a qualidade espermática através do espermograma, ultra-som e avaliação de ultraestruturas do testículo de cães que receberam cisplatina em diferentes momentos de análise espermática. A dose utilizada foi de 70 mg/m², dose terapêutica, em intervalos de 21 dias, totalizando 4 infusões. Os cães foram divididos em dois grupos de 4 animais cada, sendo que um dos grupos recebeu a quimioterapia e o protocolo de diurese para proteção renal, já o grupo controle não recebeu a cisplatina, estando sujeito apenas aos fatores ambientais e ao tratamento suporte. Os resultados obtidos demonstraram que a cisplatina influenciou na qualidade espermática de cães, pois elevou as patologias maiores e totais acima do aceitável para cães aptos a reprodução, além de alterações de volume testicular observados pelo exame ultra-sonográfico ao longo dos tratamentos e constatação da degeneração testicular em variados graus observados pela análise ultraestrutural. Portanto, infere-se que este citostático possa acarretar alterações morfofuncionais nos túbulos seminíferos / Abstract: The Veterinary Doctor's correct orientation, to the proprietors of dogs, used with reproductive purposes, submitted to the chemotherapy with cisplatin, it is important in the measure that this citostatic agent acts in the cells in constant division, could be toxicity for the testicle germ cells . The objective of that work was to evaluate the spermatic quality through the spermogram, ultra-sound and evaluation of ultrastructures of the testicle of dogs that received cisplatin in different moments of spermatic analysis. The used dose was of 70 mg/m², therapeutic dose, in intervals of 21 days, totaling 4 infusions. The dogs were divided in two groups of 4 animals each, and one of the groups received the chemotherapy and the diuresis protocol for renal protection, the group control didn't already receive the cisplatin, being just subject to the environmental factors and the treatment supports. The obtained results demonstrated that the cisplatin influenced in the spermatic quality of dogs, because it elevated the larger and total pathologies above the acceptable for capable dogs the reproduction, besides alterations of volume testicular observed by the ultra-sound exam along the treatments and verification of the degeneration testicular in varied degrees observed by the analysis ultrastructural. Therefore, it is inferred that this citostatic agent can cart alterations morphofunctional in the seminiferous tubules / Mestre
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Ácido acetilsalicílico como estratégia neuroprotetora em ratos submetidos à hiperhomocisteinemia leve : avaliações neuroquímicas e morfológicasMoreira, Daniella de Souza January 2017 (has links)
A homocisteína é um aminoácido sulfurado derivado do metabolismo da metionina. Quando os níveis plasmáticos de homocisteína ultrapassam 10-15 μM, tem-se uma condição conhecida como hiperhomocisteinemia, a qual pode ser classificada em leve (>10 μM), moderada (>30 μM) ou severa (>100 μM). A hiperhomocisteinemia leve não tem origem genética, sendo considerada um fator de risco para o desenvolvimento de doenças neurodegenerativas e vasculares, incluindo isquemia cerebral e cardíaca. Nosso grupo de pesquisa desenvolveu um modelo químico induzido de hiperhomocisteinemia leve crônica em ratos adultos jovens e, usando esse modelo foi mostrado que existe associação entre essa condição e alterações em parâmetros de inflamação e estresse oxidativo/nitrativo em tecido cerebral. O objetivo do presente estudo foi avaliar se o ácido acetilsalicílico tem papel neuroprotetor no efeito da homocisteína sobre os níveis de interleucinas IL-1β e IL-6, atividade e imunoconteúdo da acetilcolinesterase, biodisponibilidade de óxido nítrico, atividade e imunoconteúdo das enzimas antioxidantes superóxido dismutase e catalase, conteúdo de sulfidrilas e índice de dano ao DNA. Também realizamos análise morfológica por microscopia eletrônica de transmissão em córtex cerebral de ratos submetidos ao modelo. Ratos Wistar receberam homocisteína (0,03 μmol/g de peso corporal) por injeções subcutâneas duas vezes ao dia e ácido acetilsalicílico (25 mg/Kg de peso corporal) por injeções intraperitoneais uma vez ao dia, do dia 30 ao 60º dia pós-parto Ratos controles receberam o mesmo volume da solução veículo. Doze horas após a última injeção, alguns animais foram decapitados para posteriores análises bioquímicas, e outros animais foram perfundidos para posterior análise morfológica. Os resultados mostraram que os ratos submetidos à hiperhomocisteinemia leve apresentaram aumento significativo dos níveis de IL-1β, IL-6 e da atividade da acetilcolinesterase, bem como níveis reduzidos de nitritos. A homocisteína também diminuiu as atividades da superóxido dismutase e catalase, bem como o imunoconteúdo da catalase. Danos às proteínas e DNA, assim como alterações ultraestruturais também foram observadas no córtex cerebral dos animais hiperhomocisteinêmicos. O ácido acetilsalicílico preveniu totalmente o efeito da homocisteína sobre a atividade da acetilcolinesterase, atividade e imunoconteúdo da catalase, e alterações ultraestruturais. As alterações nos níveis de IL-1β, atividade de superóxido dismutase, conteúdo de sulfidrilas e dano ao DNA foram parcialmente prevenidas pelo ácido acetilsalicílico. Nossos achados mostraram que o modelo induzido quimicamente de hiperhomocisteinemia leve alterou alguns parâmetros inflamatórios, oxidativos/nitrativos e morfológicos. Nossos resultados também sugerem que o ácido acetilsalicílico desempenha um papel neuroprotetor nas condições apresentadas, pois preveniu a maior parte dessas alterações. Porém, a administração crônica do ácido acetilsalícico também apresentou efeito per se significativo de dano ao DNA, o qual deve ser melhor elucidado em estudos posteriores. / Homocysteine is a sulfur amino acid derived from methionine metabolism. When plasma homocysteine levels exceed 10-15 μM, there is a condition known as hyperhomocysteinemia, which can be classified as mild (>10 μM), moderate (>30 μM), or severe (>100 μM). Mild hyperhomocysteinemia does not have genetic origin and it is considered a risk factor for the development of neurodegenerative and vascular diseases, including cerebral and cardiac ischemia. Our research group has developed an induced chemical model of chronic mild hyperhomocysteinemia in young adult rats and using this model, it has been shown an association between this condition and changes in parameters of inflammation and oxidative/nitrative stress in brain tissue. The objective of the present study was to evaluate if acetylsalicylic acid has a neuroprotective role in the effect of homocysteine on IL-1β and IL-6 interleukin levels, acetylcholinesterase activity and immunocontent, nitric oxide bioavailability, activity and immunocontent of antioxidant enzymes superoxide dismutase and catalase, sulfhydryl content and DNA damage index. We also performed morphological analysis by transmission electron microscopy in the cerebral cortex of rats submitted to the model. Wistar male rats received homocysteine (0.03 μmol/g of body weight) by subcutaneous injections twice a day and acetylsalicylic acid (25 mg/Kg of body weight) by intraperitoneal injections once a day from the 30th to the 60th postpartum day Control rats received the same volume of vehicle solution. Twelve hours after the last injection, some animals were decapitated for subsequent biochemical analyzes, and other animals were perfused for subsequent morphological analysis. The results showed that rats submitted to mild hyperhomocysteinemia significantly increased levels of IL-1β, IL-6, acetylcholinesterase activity and reduced nitrite levels. Homocysteine also decreased the activities of superoxide dismutase and catalase, as well as catalase's immunocontent. Damage to proteins and DNA as well as ultrastructural changes were also observed in the cerebral cortex of hyperhomocysteinemic animals. Acetylsalicylic acid totally prevented the effect of homocysteine on acetylcholinesterase activity, catalase activity and immunocontent, and ultrastructural changes. Alterations in IL-1β levels, superoxide dismutase activity, sulfhydryl content and DNA damage were partially prevented by acetylsalicylic acid. Our findings showed that the chemically induced model of mild hyperhomocysteinemia altered some inflammatory, oxidative/nitrative and morphological parameters. Our results also suggest that acetylsalicylic acid plays a neuroprotective role in the conditions presented, as it prevented most of these changes. However, chronic administration of acetylsalicylic acid also had a significant effect of DNA damage, which should be better elucidated in later studies.
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Avaliação da ultraestrutura e morte celular em Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju (Cianobacteria) sob efeito da radiação ultravioletaNoyma, Natália Pessoa 29 June 2009 (has links)
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Previous issue date: 2009-06-29 / A radiação solar é essencial para a vida na Terra, fornecendo energia para a
fotossíntese e calor. Do total da radiação que tinge o planeta, 9% é representada
pela a radiação ultravioleta (UV). Estudos com grupos de cianobactérias mostram
efeitos negativos de radiação UV em processos fisiológicos, como crescimento e
sobrevivência e alterações de enzimas relacionadas ao metabolismo de nitrogênio e
fixação de CO2. Cylindrospermopsis raciborskii é uma cianobactéria filamentosa
fixadora de nitrogênio que vem se tornando uma das espécies de cianobactérias de
maior interesse de pesquisadores devido a sua potencial toxicidade e sua elevada
adaptabilidade ecofisiológica. Neste trabalho, investigou-se o efeito da radiação UV
A, UV-B e UV (A+B) na densidade, viabilidade celular e ocorrência de alterações
morfológicas por microscopia eletrônica de transmissão. Foram usadas intensidades
naturais sobre a cepa de C. racirborskii no período de 6 horas de tratamento. Os
tratamentos UV-A e UV (A+B) apresentaram efeitos negativos significativos na
densidade e integridade de membrana (99,3 e 95% de células mortas,
respectivamente), enquanto UV-B não apresentou diferença significativa na
densidade, mas induziu alteração de integridade da membrana em 57% das células
no final do tratamento. Análises ultraestruturais demonstraram modificações
morfológicas em todos os tratamentos caracterizadas principalmente por redução da
proporção de tilacóides e estruturas de armazenamento de pigmentos acessórios.
Nossos resultados demonstram a indução de morte celular significativa em cepa de
C. racirborskii pelos tratamentos UV-A e UV (A+B). Entretanto, o tratamento UV-B
parece ser menos letal para esta cepa na intensidade usada. O entendimento de
processos de morte celular em populações fitoplactônicas induzida por radiação UV
(A+B) abre novas perspectivas sobre a influência deste tipo de radiação em
ecossistemas aquáticos e suas conseqüências na persistência de espécies, fluxo
energético e ciclos biogeoquímicos. / Solar radiation is essential for life on Earth, providing energy for photosynthesis and
heat. The total radiation that reaches the Earth surface, 9% is represented by the
ultraviolet radiation (UV). Studies with cyanobacterial groups show negative effects of
UV radiation on physiological processes such as growth, survival and enzymes of
nitrogen metabolism and CO2 fixation. Cylindrospermopsis raciborskii is a
filamentous nitrogen fixing cyanobacteria that has become one of the species of
cyanobacteria of interest to researchers because of its potential toxicity and its high
ecophysiological adaptability. In this work, we investigated the effect of UV-A, UV-B
and UV (A + B) on the density, cell viability and occurrence of morphological changes
by transmission electron microscopy. Natural intensities were used on strain of C.
racirborskii in a period of 6 hours of treatment. The treatments UV-A and UV had
significant negative effects on the density and integrity of membrane (99.3 and 95%
of dead cells, respectively), while UV-B showed no significant difference in density,
but induced alteration of membrane integrity in 57% of the cells at the end of
treatment. Ultrastructural analysis showed morphological changes in all treatments
characterized mainly by reducing the proportion of thylakoid structures and pigments
accessories storage. Our results demonstrate the induction of cell death in strains of
C. racirborskii treatments by UV-A and UV. However, the UV-B treatment seems to
be less lethal to this strain in the intensity used. The understanding of processes of
cell death in phytoplanktoic populations induced by UV radiation opens new
perspectives on the influence of such radiation on aquatic ecosystems and its
consequences on the persistence of species, energy flow and biogeochemical
cycles.
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Effects of Soil Fumigations with Telone and Nemagon on Physio-Chemical and Ultrastructural Changes in Carrot Roots and Sweet Corn SeedsChen, Maureen Mei-chu 01 May 1971 (has links)
Carrots (Daucus carota L. cv. Royal Chantenay) and sweet corn vi (Zea mays L. cv. Iochief) were grown rm the Utah State University's Greenville farm in 1969 and 1970. The soil was fumigated with Telone (a mixture of 1, 3-dichloropropene and other chlorinated hydrocarbons) at the rates of 10, 20, and 30 gal/acre and Nemagon (1, 2-dibromo-3-chloropropane) at the rates of 1, 2, and 3 gal/acre one week before planting. Samples of uniformly mature carrot roots were taken for the studies of total carotenes, β-carotene, total and reducing sugars, respiration, and ultrastructural changes; and those of sweet corn seeds for the studies of total carotenoids , starch, total sugar, and total nitrogen changes.
Compared to the controls, carrots grown on fumigated soil had a significantly higher content of total carotenes, β-carotene, and total sugars, and a lower rate of respiration. The electron microscopic study indicated that the carrots from Telone (30 gal/acre) and Nemagon (3 gal/acre) fumigated soil had larger chromoplasts that contained more globuli and crystals than those of the controls. The soil fumigations with Telone and Nemagon also brought about the increase in total carotenoid content in sweet corn seeds.
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In vivo adaptation of tendon material properties in healthy and diseased tendons with application to rotator cuff diseaseTilley, Jennifer Miriam Ruth January 2012 (has links)
Degenerative disorders of the rotator cuff tendons account for nearly 75% of all shoulder pain, causing considerable pain and morbidity. Given the strong correlation between age and tendinopathy, and unprecedented population aging, these disorders will become increasingly prevalent. Improved understanding of tendon degeneration will guide the development of future diagnostic and treatments, and is therefore urgently needed. However, the aetiology and pathology of rotator cuff tendinopathy remain unclear. The complicated mechanical environment of the rotator cuff is hypothesised to influence the susceptibility of the tendons to degeneration and tearing. Studies have reported biological adaptations in torn cuff tendons indicative of increased compressive loading within the tendon. The material adaptations of healthy and degenerative cuff tendons are largely unreported but will provide further insight into the role of the mechanical environment in rotator cuff aetiology and pathology. This thesis examined the material adaptations of healthy and diseased tendons to explore the role of mechanical loading in rotator cuff pathology. The material adaptations of healthy animal tendons, and healthy and delaminated human cadaveric rotator cuff tendons, in response to different loading environments were characterised. The effects of age, tears, steroid injection and subacromial decompression surgery on the structural adaptations of human cuff tendons were also studied, as was the effect of tendon cell proliferation on the mechanical properties and degradation behaviour of collagen scaffolds. Loading environment significantly affected the structural adaptations of healthy tendons. Regions exposed to compressive and shear strains exhibited thinner fibres, shorter crimp lengths and thinner, less aligned fibrils compared with regions exposed to tensile strains alone. In healthy rotator cuff tendons, the inhomogeneous loading environment produced topographically inhomogeneous structural adaptations. The tendons of a delaminated rotator cuff exhibited less topographical variation in properties and thinner, less aligned fibrils compared with healthy cuff tendons. Torn cuff tendons exhibited thinner fibrils and shorter crimp lengths compared with control samples. These adaptations were identifiable early in the disease progression, and neither steroid injection nor subacromial decompression surgery significantly influenced these adaptations at seven weeks post‐treatment. Significant correlations between decreasing dimensions and increasing tear size were found when age was included as a confounding factor, reflecting the importance of age and tear size in determining the material properties of tendons. Tendon cell proliferation influenced the mechanical properties and degradation behaviour of the collagen scaffolds, emphasising the integral role of cells in the functional adaptation of biological materials. These results demonstrate the effect of mechanical environment on the material adaptations of tendons. They also indicate the importance of the complicated mechanical environment experienced by the rotator cuff tendons in predisposing the tendons to degeneration and tearing. The observed material adaptations of degenerative and torn tendons suggest that rotator cuff pathology is associated with increased levels of compressive and/or shear strains within the tendon. These changes begin early in the disease progression and neither steroid injection nor sub‐acromial decompression surgery are capable of reversing the changes in the timeframe investigated. These findings highlight the urgent clinical need for pre‐rupture diagnostic techniques for the detection of early pathological changes in the rotator cuff. They also emphasize the requirement for new intervention strategies that restore the healthy mechanical environment and reverse early pathological adaptations in order to prevent catastrophic failure of the tendons.
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Diagnóstico de influência local no modelo de calibração ultraestrutural com réplicas / Local influence diagnostics in ultrastructural calibration model with replicasAndrade, Bruno Pinheiro de 09 December 2016 (has links)
Este trabalho tem como proposta apresentar a metodologia de diagnóstico de influência local de Cook (1986) conjuntamente com a metodologia de seleção da perturbação adequada proposta por Zhu et al. (2007) no modelo de calibração ultraestrutural com réplicas. A metodologia de Cook (1986) ser´a utilizada para investigar a robustez e a sensibilidade do modelo, onde os esquemas de perturbação adotados foram ponderação de casos e na variável resposta. Perturbar o modelo e/ou os dados de forma arbitrária pode conduzir a interpretações sobre a análise de diagnóstico e a conclusões equivocadas. Portanto, este trabalho irá avaliar as perturbações propostas segundo a metodologia de Zhu et al. (2007) e caso as perturbações não sejam adequadas, iremos propor uma nova forma de fazer as perturbações. Foi utilizado como aplicação a análise de um conjunto de dados com réplicas balanceadas e foram avaliadas quais patamares e laboratórios exercem um efeito desproporcional nas inferências feitas sob o modelo. / This paper aims to present the local influence diagnostic methodology of Cook (1986) along with the selection of the appropriate perturbation schemes proposed by Zhu et al. (2007) in ultrastructural calibration model with replicas. The methodology of Cook (1986) will be used to investigate the robustness and sensitivity of model, where the adopted perturbation schemes were weighting cases and response variables. Perturbing the model and/or data in an arbitrary way can lead to miss interpretations of diagnostic analysis and wrong conclusions. Therefore, this study will evaluate the induced perturbations according to the methodology of Zhu et al. (2007) and if the perturbations are not suitable, we will propose a new way of perturbing the model or the data. As an application it was considered a data set with balanced repeated replication to evaluate which levels and laboratories exercise a disproportional effect on inferences made in the model.
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Avaliação da exigência nutricional na fase inicial do crescimento de espécies florestais nativas / Evaluation of the nutritional requirements of native forest species in their initial plant growthSorreano, Maria Claudia Mendes 15 December 2006 (has links)
O projeto tem como hipótese de trabalho que as espécies florestais tem exigências nutricionais e respostas ao stress nutricional diferenciados e que a complementação nutricional é um dos principais fatores determinantes do sucesso de projetos de recuperação florestal. Este trabalho teve como objetivo avaliar as exigências nutricionais e os efeitos da omissão de macro e micronutrientes em espécies florestais nativas de diferentes grupos sucessionais, mais usadas ou indicadas para recuperação de áreas degradadas no Estado de São Paulo. As espécies estudadas, agrupadas de acordo com o seu grupo sucessional, foram: pioneiras e secundárias iniciais - Tapirira guianensis, Ceiba speciosa, Cecropia pachystachya, Croton urucurana, Lonchocarpus muehlbergianus, Acacia polyphylla, Enterolobium contortisiliquum, Inga uruguensis, Guazuma ulmifolia, Aegiphila sellowiana, Cytharexyllum myrianthum; secundárias tardias e clímax - Astronium graveolens, Myroxylon peruiferum, Hymenaea courbaril, Cariniana legalis, Esenbeckia leiocarpa, Genipa americana. O experimento foi conduzido em casa de vegetação, em blocos ao acaso, com três repetições e treze tratamentos para cada espécie, empregando a técnica de diagnose por subtração (-N, - P, -K, -Ca, -Mg, -S, -B, -Cu, -Fe, -Mn, -Mo, -Zn), sendo que, num dos tratamentos, as espécies foram cultivadas em solução nutritiva completa, com todos os macros e micronutrientes. As plântulas foram transplantadas para vasos de 2 L contendo solução nutritiva. Foram avaliadas: altura, diâmetro, número de folhas e ramos, produção de matéria seca da parte aérea (folhas e ramos + caule) e raízes, teor de nutrientes da matéria seca da parte aérea e raízes. Para avaliar as alterações ultraestruturais causadas pela deficiência de nutrientes em Ceiba speciosa foi utilizada a técnica de microscopia eletrônica de transmissão. Concluiu-se que: 1) a omissão dos nutrientes resultou em alterações morfológicas traduzidas em anormalidades visíveis, sendo que, os micronutrientes B, Fe Cu e Zn quando omitidos causam os primeiros sintomas, seguidos pelos macronutrientes N, P e K, para os diferentes grupos ecológicos; 2) as mudas de espécies iniciais da sucessão mostraram-se mais sensíveis à omissão de macro e micronutrientes demonstrando os sintomas de deficiências visuais mais rapidamente que as mudas de espécies de crescimento lento; 3) quando se agrupa a espécie florestal independente do grupo ecológico a que elas pertencem, verificamos que essas apresentaram um denominador comum, ou seja, os tratamentos com omissão de N, Ca, B, Cu e Zn foram os que mais afetaram o incremento em altura, diâmetro do colo, número de ramos e folhas, para as 17 espécies estudadas. Já a produção de matéria seca foi prejudicada pela omissão de N, Cu, Fe e Zn; 4) a variação do teor foliar de macro e micronutrientes deve refletir as exigências distintas das diversas espécies; 5) a omissão de macro e micronutrientes provocou alterações na ultraestrutura de células do limbo foliar de Ceiba speciosa, relacionadas aos sintomas visíveis de deficiência nutricional; 6) este estudo deve ser considerado como preliminar para trabalhos de campos destinados a programas de correção de solos e adubação para as diferentes espécies. / The working hypothesis of this research is that native forest species have different nutritional demands and show diverse response to the nutritional stress, and that addition of nutrients could be an important factor for the success of projects designed for the recovery of forests. This work had the goal of assessing both the nutritional requirements and the effect of the deficiences of macro and micronutrients on native species of various successional groups more extensively used in the recovery of degraded areas of the State of São Paulo. The following species were studied: pioneer and secondary - Tapirira guianensis, Ceiba speciosa, Cecropia pachystachya, Croton urucurana, Lonchocarpus muehlbergianus, Acacia polyphylla, Enterolobium contortisiliquum, Inga uruguensis, Guazuma ulmifolia, Aegiphila sellowiana, Cytharexyllum myrianthum; secondary late and climax - Astronium graveolens, Myroxylon peruiferum, Hymenaea courbaril, Cariniana legalis, Esenbeckia leiocarpa, Genipa americana. The experiment was conducted in the greenhouse with thirteen treatments with three replicates under a completely randomized design. The technique of diagnosis by subtraction was used with the following treatments for all species: complete, -N, -P, -K, -Ca, -Mg, -S, -B, -Cu, -Fe, -Mn, -Mo, -Zn. Young plants were grown in nutrient solution in 2L pots. The following variables were evaluated: height, diameter, number of leaves and branches, dry matter both in tops and roots, nutrient content in the dry matter. Changes in ultrastructure caused by the deficiencies of nutrients in Ceiba speciosa, was observed by the technique of electron microscopy. Main conclusions were as follows: 1) The omission of nutrients caused symptoms of deficiency. The first to show up were due to lack lack of B, Fe, Cu and Zn, being followed by N, P and K; 2) The starter plants species were more sensitive to the deficiencies showing symptoms earlier than species of slow rate of growth; 3) When the species are grouped independently of the ecological group their belong to, it is seem that there is a common denominator among them, that is to say, treatments with omission on N, Ca, B, Cu, Zn affected most height, stem diameter, number of branchs and of leaves. On the other hand dry matter wield was more affected by lack of N, Cu, Fe, Zn; 4) The variation in the leaf content of the various nutrients very likely reflects differences in requirements there of; 5) Omissions of both macro and micronutrients caused changes in the ultrastructure of Ceiba speciosa related to the visual symptoms of deficiency; 6) This study is to be considerate of a preliminary nature for field work designed to set up programs of correction and fertilization for the various species.
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