Thesis (M.Sc. (Clinical Pathology))--Mahidol University, 1984.

The cellular degradation of the low density lipoprotein (LDL) receptor, and its ligand, LDL, were investigated in order to clarify certain mechanistic aspects of these important processes. Long-term lymphoblastoid cell lines and cultured human skin fibroblasts were used to examine the fate of ¹²⁵I-LDL subsequent to its uptake via receptor-mediated endocytosis. In both cases, binding activity was saturable, depended on the presence of calcium ions in the medium, and was calculated to have an equilibrium dissociation constant at 4ᵒC of 2 μg ¹²⁵I-LDL/ml. No high-affinity binding was detected when the ligand was modified by acetylation. After incubating the monolayers at 37°C LDL/LDL receptor complexes were internalized, and the receptors were recycled back to the surface within about 10 minutes. Apolipo-protein B in the LDL particles was largely degraded to the amino acid level: chloroquine, a lysosomotropic agent, inhibited the formation of the ¹²⁵I-LDL degradation products. Cells obtained from a number of heterozygous and homozygous familial hypercholesterolemic patients, as expected, bound markedly reduced amounts of ligand. The half-life of ¹²⁵I-LDL was measured after it had been introduced into cultured fibroblasts by one of the following processes: (i) uptake via receptor-mediated endocytosis in human skin fibroblasts with normal LDL receptors, or (ii) incorporation via scrape-loading into fibroblasts defective in LDL receptor content. The half-lives obtained were about 1 hour and 50 hours, respectively, indicating that efficient degradation of LDL occurred only when it was deIivered to lysosomes via receptor-mediated endocytosis.

In male athletes from different sports, isokinetic knee extensor, and in orienteers also plantar flexor peak torque (PT), contractional work (CW) and integrated surface electromyograms (iEMG) were analysed. Single contraction PT, CW and iEMG in sprinters and marathon runners were signi­ficantly correlated to the cross-sectional area (CSA) of m. quadriceps, and to the Type II fibre area of m. vastus lateralis. When correcting PT, CW and iEMG for CSA of m. quadriceps, such correlations were found only for Type IIA fibre area at 180° s~1. Elec- tromyographically, m. vastus lateralis (biopsied muscle) was representative for m. quadriceps. Calculated optimal mean power (CW s~1) and electrical efficacy (CW/iEMG) approximated for sprinters 450° s-1 and for marathon runners 270° s~1, i.e. velocities at or above the upper limit of the dynamometers. In orienteers, plantar flexor PT increased during winter training, but decreased during competitive season. Knee extensor PT increased over the whole year. At 30 and 60° s~1 only knee extensor PT was negatively associated with the running velocity at onset of blood lactate accu­mulation (VOBLA)- Changes in VOBLA during winter period were negatively associated with changes in knee extensor PT at 180° s~1. During competitive season, changes in Vobla were negatively associated with the ratio quality : quantity running. In ice hockey players PT varied non-systematically with training and games. The biopsy specimens of marathon runners showed irregular fibre shapes, an in­creased amount of connective tissue and central fibre nuclei, indicating an early strain disease or functional adaptation to extreme demands. During repetitive contractions in sprinters and marathon runners, fatigue, i.e. slope of decline in CW, was significantly associated with the Type II fibre area of m. vastus lateralis. For knee extensors of sprinters, ice hockey players and orienteers, a steep de­crease in CW/iEMG was observed. In contrast, knee extensors of marathon runners and plantar flexors of orienteers showed an almost unaltered CW/iEMG throughout the test. The knee extensor endurance level (CW/iEMG) was significantly correlated to the maximal oxygen uptake. In orienteers, an increase in endurance level of both tested muscle groups during winter training parallelled an increase in VOBLA and V02obla- In hockey players, fatigue and endurance pattern (CW and CW/iEMG) changed non-systematically with training and games. In conclusion, isokinetic measurements and iEMG reflect the structural properties of the knee extensor muscles in sprinters and marathon runners. The demonstrated characteristics and changes in leg muscle function in different groups of athletes apparently reflect varying demands from different sports activities. / <p>S. 1-31: sammanfattning, s. 33-84: 6 uppsatser</p> / digitalisering@umu

Made available in DSpace on 2015-07-22T20:50:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo deste trabalho é estabelecer os valores hematológicos e avaliar a capacidade fagocítica de macrófagos peritoneais do robalo relacionado ao sexo, estádio de maturação gonadal e ciclo sazonal. Foi coletado sangue de 135 animais e utilizado para as determinações de: número de eritrócitos, hematócrito, taxa de hemoglobina, cálculos dos índices hematimétricos (volume corpuscular médio e concentração de hemoglobina corpuscular média), contagens total e diferencial de leucócitos e de trombócitos. A capacidade fagocítica e o índice fagocítico foram determinados após inoculação de S. cerevisiae na cavidade peritoneal. Os resultados hematológicos separados por sexo mostraram valores do número de eritrócitos, trombócitos e leucócitos totais em machos estatisticamente superiores àqueles em fêmeas. Já os valores de VCM em fêmeas foram superiores àqueles em machos. Quanto aos valores do número de eritrócitos, do hematócrito e da taxa de hemoglobina analisados separadamente por sexo e estádio de maturação gonadal mostraram-se significantemente elevados em machos no estádio maduro e diminuídos no estádio repouso. A análise dos resultados hematológicos e da atividade fagocítica relacionada ao sexo e ao ciclo sazonal mostrou diferenças estatisticamente significantes em ambos os sexos com hematócrito e taxa de hemoglobina baixos no inverno e altos nas demais estações, volume corpuscular médio altos no verão e baixos no inverno e outono; leucócitos totais e trombócitos baixos na primavera e elevados no outono; linfócitos baixos no inverno e verão e elevados na primavera; capacidade fagocítica e índice fagocítico elevados no verão e baixos no inverno e outono. Os resultados mostraram que os valores hematológicos em machos foram estatisticamente superiores àqueles em fêmeas, os valores eritrocitários em machos aumentam com o avanço da maturação gonadal e que o inverno corresponde à estação do ano menos favorável à resposta hematológica e fagocítica para a sobrevivência do robalo criado em cativeiro. Os parâmetros estudados poderão ser utilizados, para a manutenção e controle desta espécie na criação em cativeiro. / The objective of this work was to determine hematological parameters and the phagocytic capacity of peritoneal macrophages of the fat snook related to sex, stage of gonadal maturation and seasonal cycle. The hematological results did not show significant differences between males and females. With respect to stage of gonadal maturation, only erythrocytes numbers (RBC), in females, was found to be significantly elevated in stage III (maturing) and decreased in V (spent). An analysis of the results of the erythrocyte and leukocyte series, thrombocytes and phagocytic activity related to sex and seasonal cycle showed statistically significant differences: a) in males, hematocrit (Ht) and hemoglobin concentration (Hb) were elevated in the spring and low in the winter; b) in both sexes, mean corpuscular volume (MCV) was high in the spring and summer and low in the fall; c) in females, thrombocytes numbers were elevated in the fall and low in the other seasons; d) in both sexes, phagocytic capacity (PC) and phagocytic index (PI) were higher in the summer and lower in the fall. The results showed that spring and summer correspond to seasons of the year for better hematological and phagocytic responses for survival of the fat snook in its natural habitat. The parameters studied could be utilized for evaluation of the health status in its own habitat or in captivity. / TEDE / BV UNIFESP: Teses e dissertações