Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 96-103).

Herniation of the intervertebral disc is a pathological condition characterized by protrusion of the tissue posterio-laterally, often impinging on the spinal chord or nerve roots. The disease is accompanied by a reduction in the average molecular weight and viscosity of the disc proteoglycans, in excess of that which normally occurs with increasing age. The proteoglycans of disc however have not been examined in terms of the modern concepts of cartilage matrix structure. Bovine nasal cartilage, has been shown to contain proteoglycan aggregates, trapped in the intersticess of a collagen network, which can be dissociated with 4M guanidine hydrochloride into diffusible proteoglycan subunits and a multicomponent "linking" fraction. A similar system was thought to occur in the intervertebral disc. It seemed possible that, if such a system was present in the disc, the reduction in the molecular weight and viscosity of the proteoglycans with increasing age and herniation could be due to a decrease in proteoglycan aggregation. The present study showed that proteoglycan aggregates similar to those of bovine nasal cartilage are found in the human intervertebral disc, but that they only represent 5% of the total proteoglycans in the tissue. In contrast, bovine nasal cartilage contained 70% of the proteoglycans in the aggregated form. A novel modification of the extraction procedure was devised by which it was possible to assess the degree of proteoglycan aggregation. Sequential extraction of the tissue with a weak and strong electrolyte (0.4 M and 4M guanidine hydrochloride) selectively removed non-aggregated and aggregated proteoglycans respectively. This procedure provides a new and rapid method for assessing the degree of proteoglycan aggregation in a variety of connective tissues. The small proportion of aggregate in the disc was almost exclusively located in the annulus fibrosus. Re-aggregation studies suggested that both disc and cartilage contain two proteoglycans, only one of which is capable of forming aggregates. Examination of the proteoglycans in a limited number of discs suggested that the degree of aggregation did not change with increasing age. Since, in addition, aggregates represent only a small proportion of the disc proteoglycans, it appeared unlikely that a decrease in the degree of aggregation could account for the decrease in molecular weight and viscosity of the disc proteoglycans observed with increasing age and/or degenerative disc disease. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate

Thesis (M.Sc.). / Written for the Dept. of Pharmacology and Therapeutics. Title from title page of PDF (viewed 2009/06/29). Includes bibliographical references.

published_or_final_version / Orthopaedics and Traumatology / Doctoral / Doctor of Philosophy

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES

Thesis (M.S.P.H.)--University of South Florida, 2008. / Title from PDF of title page. Document formatted into pages; contains 45 pages. Includes bibliographical references.

Hipotrofía nos músculos que estabilizam a coluna tem sido identificada nos pacientes com lombalgia. Entretanto, não se sabe se a perda muscular é causa ou conseqüência desta disfunção, nem se ela é influenciada pelo tipo de alteração discal que o indivíduo apresenta. Este estudo testou a hipótese de que a hipotrofía dos pacientes com lombalgia seja dependente do tipo de alteração discal. Para avaliar a condição muscular em diferentes tipos de alteração discal, optou-se por um estudo retrospectivo e por uma seleção aleatória de 78 exames de ressonância magnética de indivíduos com lombalgia. Em cada exame foram realizadas medidas quantitativas da porcentagem de gordura na área de secção transversa dos mm. multífidus e psoas, nos três últimos níveis da coluna lombar. A alteração discal foi encontrada em 95% dos exames, sendo o abaulamento o achado de imagem mais freqüente, seguido pela protrusão discal. A porcentagem de gordura variou conforme o tipo de alteração discal. Nos níveis com abaulamento há em ambos os músculos estudados 6% a mais de tecido gorduroso do que nos níveis onde há protrusão e esta diferença foi estatisticamente significante. Músculos nos níveis onde há protrusão sem fissura no anel fibroso apresentaram maior substituição gordurosa do que aqueles onde há protrusão com fissura. A porcentagem de gordura foi influenciada por características anatômicas como músculo estudado e nível da coluna, e por características como idade e sexo dos sujeitos. Estes resultados indicam que a hipotrofía muscular em pacientes com lombalgia não é um processo uniforme e generalizado, mas sim correlacionado a diferentes variáveis, entre elas o tipo de alteração discal que o paciente apresenta. / Low back pain patients present atrophy on muscles responsible for spine stabilization. However, it is not clear if muscle waste is related to the cause or if it is a consequence of this disfunction. Nor it is clear if muscle athophy is affected by the type of disc pathology. This study tested the hypothesis that muscle waste in low back pain patients influenced by the type of disc derangement. Magnetic resonance scans of 78 low back pain patients were randomly analysed. Cross sectional area percentage of fat tissue in multifidi and psoas major muscles was measured on the lower levels of the lumbar spine. Disc pathology was found in 95% of the exams and disc bulge was the most frequent abnormality, followed by disc protrusion. Fat percentage varied according to disc pathology and this difference was statistically significant. Muscles on levels with disc bulge presented 6% more fat deposits than muscles on levels with disc protrusion. Muscles on levels with discs without anular tear present more fat infiltration than muscles on levels with anular tear. Fat percentage was also influenced by anatomic aspects such as evaluated muscle and spine level, and sample characteristics as age and sex. The results indicated that muscle atrophy in low back pain patients is not a uniform and generalized feature. It is correlated to different variables, such as type of disc pathology

Hipotrofía nos músculos que estabilizam a coluna tem sido identificada nos pacientes com lombalgia. Entretanto, não se sabe se a perda muscular é causa ou conseqüência desta disfunção, nem se ela é influenciada pelo tipo de alteração discal que o indivíduo apresenta. Este estudo testou a hipótese de que a hipotrofía dos pacientes com lombalgia seja dependente do tipo de alteração discal. Para avaliar a condição muscular em diferentes tipos de alteração discal, optou-se por um estudo retrospectivo e por uma seleção aleatória de 78 exames de ressonância magnética de indivíduos com lombalgia. Em cada exame foram realizadas medidas quantitativas da porcentagem de gordura na área de secção transversa dos mm. multífidus e psoas, nos três últimos níveis da coluna lombar. A alteração discal foi encontrada em 95% dos exames, sendo o abaulamento o achado de imagem mais freqüente, seguido pela protrusão discal. A porcentagem de gordura variou conforme o tipo de alteração discal. Nos níveis com abaulamento há em ambos os músculos estudados 6% a mais de tecido gorduroso do que nos níveis onde há protrusão e esta diferença foi estatisticamente significante. Músculos nos níveis onde há protrusão sem fissura no anel fibroso apresentaram maior substituição gordurosa do que aqueles onde há protrusão com fissura. A porcentagem de gordura foi influenciada por características anatômicas como músculo estudado e nível da coluna, e por características como idade e sexo dos sujeitos. Estes resultados indicam que a hipotrofía muscular em pacientes com lombalgia não é um processo uniforme e generalizado, mas sim correlacionado a diferentes variáveis, entre elas o tipo de alteração discal que o paciente apresenta. / Low back pain patients present atrophy on muscles responsible for spine stabilization. However, it is not clear if muscle waste is related to the cause or if it is a consequence of this disfunction. Nor it is clear if muscle athophy is affected by the type of disc pathology. This study tested the hypothesis that muscle waste in low back pain patients influenced by the type of disc derangement. Magnetic resonance scans of 78 low back pain patients were randomly analysed. Cross sectional area percentage of fat tissue in multifidi and psoas major muscles was measured on the lower levels of the lumbar spine. Disc pathology was found in 95% of the exams and disc bulge was the most frequent abnormality, followed by disc protrusion. Fat percentage varied according to disc pathology and this difference was statistically significant. Muscles on levels with disc bulge presented 6% more fat deposits than muscles on levels with disc protrusion. Muscles on levels with discs without anular tear present more fat infiltration than muscles on levels with anular tear. Fat percentage was also influenced by anatomic aspects such as evaluated muscle and spine level, and sample characteristics as age and sex. The results indicated that muscle atrophy in low back pain patients is not a uniform and generalized feature. It is correlated to different variables, such as type of disc pathology