Made available in DSpace on 2014-06-11T19:35:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-16Bitstream added on 2014-06-13T19:24:58Z : No. of bitstreams: 1 steiner_ml_dr_botfm.pdf: 512184 bytes, checksum: d483eb904ab985864204da709525a408 (MD5) / Libbs Farmaceutica / Avaliar comparativamente a eficácia da terapêutica de reposição hormonal (TRH) de baixa dose isolada ou associada à sinvastatina no comportamento de marcadores de risco cardiovasculares e do perfil lipídico e lipoprotéico em mulheres sintomáticas e com dislipidemia na pós-menopausa. Duzentas e quarenta e duas mulheres na pós-menopausa, sintomáticas e com dislipidemia foram randomizadas em três grupos de tratamento: A) estradiol (E2) 1mg/acetato de noretisterona (NETA) 0,5mg [E2/NETA] + sinvastativa 20mg; B) E2/NETA + placebo; e C) sinvastatina 20mg + placebo. A eficácia de cada tratamento foi avaliada pela melhora do perfil lipídico e lipoprotéico e dos sintomas climatéricos ao final de 16 semanas de tratamento. O colesterol total, o LDL-C, o colesterol não-HDL e a Apo B diminuíram de forma significativa (p<0,0001) ao final de 16 semanas no grupo que utilizou E2/NETA + sinvastatina e naquele tratado com sinvastatina + placebo. A relação Apo B/Apo A1 também apresentou redução significativa nestes dois grupos (p<0,0001 e p=0,0026 respectivamente). A Apo A1 diminuiu apenas no grupo que recebeu E2/NETA + sinvastatina (p=0,0055). O grupo E2/NETA + placebo não apresentou alterações significativas no perfil lipídico e lipoprotéico entre as visitas basal e final. Aquele que utilizou E2/NETA + sinvastatina apresentou redução significativa do HDL-C e da Apo A1 quando comparado às usuárias de sinvastatina + placebo (p=0,0233 e p=0,0231 respectivamente). No alívio dos sintomas climatéricos, os grupos que utilizaram E2/NETA foram superiores a sinvastatina + placebo. Em mulheres na pós-menopausa com dislipidemia, a associação de E2/NETA em baixa dose com sinvastatina aliviou os sintomas climatéricos de forma semelhante à observada com a E2/NETA isolada e melhorou o perfil lipídico e lipoprotéico de modo semelhante ao uso isolado da sinvastatina. O uso de E2/NETA sem... / To evaluate low-dose hormone therapy (HT) + simvastatin for vasomotor symptoms and cardiovascular risk markers. Symptomatic postmenopausal women (n=242) with dyslipidemia were randomized to one of three treatment groups: A) 1mg estradiol/0.5mg norethisterone acetate (E2/NETA) + 20mg simvastatin; B) E2/NETA + placebo; or C) 20mg simvastatin + placebo. Lipid and lipoprotein profiles and menopausal symptoms were evaluated after 16 weeks. Total cholesterol, LDL cholesterol, non-HDL cholesterol and Apo-B decreased (p<0.0001) in groups A and C, as did Apo-B/Apo-A1 (p<0.0001 and p=0.0026, respectively). Apo-A1 decreased only in group A (p=0.0055). HDL cholesterol and Apo-A1 were lower in A than C (p=0.0233 and p=0.0231, respectively). Relief of menopausal symptoms was better in A and B compared to C. HT + simvastatin were effective for the treatment of symptomatic postmenopausal women and improved the lipid profile similar to simvastatin alone. It also delivered an improvement in the simultaneous treatment of menopausal symptoms and dyslipidemia

Made available in DSpace on 2014-10-09T12:28:04Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:23Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Eliana Cotta de Faria / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T21:29:39Z (GMT). No. of bitstreams: 1 Bassora_FernandaDutraSantiago_M.pdf: 2612060 bytes, checksum: 0ddcd23de6e1ce1f879247d7a9c9b2d7 (MD5) Previous issue date: 2007 / Resumo: Está bem estabelecida na literatura especializada a associação inversa entre as concentrações plasmáticas de colesterol das lipoproteínas de alta densidade (HDL-C) e a incidência de doença arterial coronariana (DAC). Além de propriedades anti-oxidante, anti-inflamatória e anti-trombótica, a HDL participa do transporte reverso de colesterol, via pela qual o colesterol é captado das lipoproteínas e das membranas células periféricas e transportado ao fígado para sua excreção na forma livre ou de ácidos biliares. A lipase hepática (LH) possui função crucial no transporte reverso do colesterol, por sua atividade lipolítica e pela função de ligante à lipoproteínas facilitando sua captação tissular. A proteína de transferência de ésteres de colesterol (CETP), e mesma importância metabólica, promove a troca de ésteres de colesterol por triglicérides entre a HDL e as lipoproteínas ricas em triglicérides. Mutações nos genes que codificam estas proteínas têm sido muito estudadas para se compreender a função destas no metabolismo lipídico. O modelo experimental da hiperalfalipoproteinemia tem sido utilizado no decorrer dos últimos anos com o intuito de elucidar os mecanismos de ação da HDL e das proteínas reguladoras do seu metabolismo. A hiperalfalipoproteinemia é caracterizada pelo aumento das concentrações de HDL-C e é causada principalmente por deficiências genética de CETP e/ou LH. Os objetivos desta dissertação foram o de se estabelecer à modulação da hiperalfalipoproteinemia sobre os parâmetros antropométricos, bioquímicos, moleculares (¿514C/T do gene da LH e I405V do gene da CETP) e radiológicos (espessura da camada íntima média de carótidas) em uma amostra populacional brasileira. O estudo foi conduzido em 291 voluntários de ambos os sexos, classificados como hiperalfalipoproteinemicos (Hiper-A), HDL-C =68mg/dL, ou controles, HDL-C<68 e =32 mg/dL, de acordo com o valor do percentil 90, obtido em um estudo prévio do Laboratório de Lípides a partir população normolipidêmica. Os polimorfismos LH-514C/T e CETP I405V foram identificados através de técnicas de reação em cadeia polimerase (PCR) e a espessura da camada íntima-média de carótidas (EIM) pela ultra-sonografia de alta resolução. Em um primeiro trabalho observou-se em um sub-grupo de 169 indivíduos, com a medida da EIM, que somente a idade foi correlacionada com a EIM na hiperalfalipoproteinemia, enquanto que em controles houve modulação positiva pela idade, sexo masculino, pressão arterial sistólica, e controversamente com relatos da literatura, com HDL-C. Apesar de Hiper-A possuir um perfil com maior número de fatores de risco cardiovasculares, a semelhança encontrada na EIM de carótidas, assim como, da freqüência de EIM maior que 1 mm poderia, em parte, ser explicada pela grande diferença de modulação entre os grupos apontando para um traço protetor contra a aterosclerose carotídea em hiperalfalipoproteinemia. A ateroproteção reduzida em controles, tanto em homens quanto em mulheres, está de acordo com a observada associação negativa neste grupo entre EIM e a CETP com possível presença de HDL com a composição química alterada (ricas em TG e pobres em ésteres de colesterol), e ocorreu possìvelmente no sub-grupo masculino, com perfil pró-aterogênico evidente. Em um segundo trabalho, no sub-grupo de 169 indivíduos, com a medida da EIM, foi avaliado o efeito do polimorfismo LH-514C/T sobre a espessura da camada íntima-média de carótidas na hiperalfalipoproteinemia. Não se observou nenhuma variação de EIM em ambos os grupos em função deste polimorfismo. Quando comparados os grupos, o genótipo CC do polimorfismo LH-514C/T mostrou apenas tendência a maior EIM de carótidas em hiperalfalipoproteinemia (p<0,09), mas a freqüência de EIM maior que 1 mm foi igual. Em um terceiro trabalho, em 282-291 indivíduos foram avaliadas as semelhanças de freqüências entre os polimorfismos LH-514C/T e CETP I405V na hiperalfalipoproteinemia e normolipidemia. Ambos apresentaram altas freqüências, similares entre grupos e entre o polimorfismo LH-514C/T, CC 39%, CT+TT 61%; e o polimorfismo CETP I405V: II 26%, IV+VV 74% e CTL: CC 40%, CT+TT 60%, II 43% e IV+VV 57%. Descrevemos o polimorfismo LH-514C/T na hiperalfalipoproteinemia os TT vs CC apresentaram cintura menor, concentrações mais baixas de colesterol plasmático (C), fosfolípides (FL), LDL-C, estimativa do tamanho da LDL (LDL-C/ApoB). O polimorfismo CETP I405V na hiperalfalipoproteinemia em VV vs II, mostrou alta pressão arterial sangüínea e menores concentrações plasmáticas de HDL2TG e HDL3TG. O genótipo IV teve maiores concentrações plasmáticas de ApoAI e pressão arterial diastólica quando comparado com o genótipo II. Em resumo esta dissertação aponta para efeitos ateroprotetores ou neutros da hiperalfalipoproteinemia em uma amostra de população brasileira sobre a aterosclerose carotídea, inclusive no polimorfismo LH -514C/T. Os polimorfismos LH-514C/T e CETP I405V foram muito semelhantes com relação aos lípides e lipoproteínas séricos, mas não às proteínas reguladoras, oferecendo modulação protetora na hiperalfalipoproteinemia / Abstract: There is an inverse relationship between plasma concentration of high-density lipoprotein (HDL-C) and the risk of coronary arterial disease (CAD). Beyond anti-oxidant, anti-inflammatory and anti-thrombotic properties, HDL plays a role on the reverse cholesterol transport, where cholesterol is taken from lipoproteins and peripheral cells to the liver for excretion. Hepatic lipase (HL) plays a key role in this process, by its lipolitic activities and ligand functions. Cholesterol ester transfer protein (CETP), of equal metabolic importance, facilitates the exchange of cholesterol ester and triglycerides between HDL and triglyceride rich-lipoproteins. Mutations and polymorphisms of these enzymes have being studied in order to evaluate its activity and metabolic consequences. Hyperalphalipoproteinemia (Hyper-A) has being used in the latest years with the purpose of evaluating the anti and pro-atherogenic mechanisms of HDL and of regulating proteins. The aim of this work was to establish the modulation of hyperalphalipoproteinemia in relation to controls on the anthropometric, biochemical, radiological and molecular manifestations. This study was conducted on 291 volunteers, classified as Hyper-A, HDL-C=68mg/dL and controls, HDL-C <68 e 32 mg/dL according to the percentile 90th, obtained from a local normolipidemic population study. We determined clinic data, lipid, lipoproteins and radiological parameters of volunteers. The HL-514C/T and CETP I405V polymorphism were determined by polymerase chain reaction methods. The carotid intima-media thickness measurements were performed high performance ultrasound. We showed in the first manuscript that although possessing a higher risk coronary vascular disease profile the similarity found in carotid could in part be explained by the striking differences in its modulation between the two groups, indicating a protective trait against carotid atherosclerosis in hyperalphalipoproteinemia. In the Hyper-A population, was only correlated with age, while in controls had a positive correlation with age, male sex, systolic blood pressure, and surprisingly with HDL-C. This dissociation between IMT and HDL-C could be accounted for by a small HDL particle number in CTL. In the manuscript 2, the ¿514C/T polymorphism did not contribute to variations in the carotid IMT and Hyper-A did not modulate the IMT variations, contrary to Rundek et al., (2002) who investigated the ¿514C/T polymorphism on variations in the carotid IMT in 87 stroke-free subjects suggested that CC genotypes had increase of carotid IMT, FMT and HALP. The HL-514C/T e CETP I405V polymorphisms, were no associate, were highly prevalent in the two groups but were not associated with HDL-C. In Hyper-A, LH-514C/T induced lower plasma cholesterol (C), phospholipids (PL), LDL-C and LDL size (LDL-C/ApoB). In Hyper-A CETP I405V decreased blood pressure, reduced TG in HDL subfractions 2 and 3 of (HDL2TG and HDL3TG) and increase ApoAI. The HL -514C/T polymorphism in Hyper-A the TT vs CC had lower waist hip-circumference, cholesterol (C) concentrations, phospholipids (PL), LDL-C and estimated size particle by LDL-C/ApoB. The genotype TT was different between 2 groups: in Hyper-A with relation the CTL, had lower HL, estimated size particle by TG/HDL-C and higher HDL2C, HDL3C, HDL3TG, ApoAI and C concentrations and had higher C, estimated size particle by LDL-C/ApoB, ApoAI, HDL2C, HDL3C and estimated size particle by TG/HDL-C. The CETP I405V polymorphism in Hyper-A, the VV vs II had higher Systolic Blood Pressure and lower HDL2TG e HDL3TG concentrations. The IV genotype had higher ApoAI concentration and Diastolic Blood Pressure. In Hyper A, the VV genotype had higher HDL2C, HDL3C, ApoAI, e TG concentrations and reduced concentration of VLDL- and estimated size particle of LDL by TG/HDL-C. In summary, this work indicates an athero-protector and neutral effect on the carotid atherosclerosis in Hyper-A between HL-514C/T and CETP I405V polymorphisms both modulated for plasma lipids more atheroprotective / Mestrado / Ciencias Basicas / Mestre em Clinica Medica

Orientadores: Eliana Cotta de Faria, José Eduardo Tanus dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-16T16:38:14Z (GMT). No. of bitstreams: 1 Zago_VanessaHelenadeSouza_M.pdf: 4029424 bytes, checksum: 82a248a89f7f9c4b4bee67ad6c6f0d07 (MD5) Previous issue date: 2010 / Resumo: O óxido nítrico (NO) é produzido no endotélio vascular pela óxido nítrico sintase endotelial (eNOS), enzima regulada negativamente pela presença do polimorfismo T- 786C, levando à disfunção endotelial. A lipoproteína de alta densidade (HDL) têm funções anti-aterogênicas bem estabelecidas, incluindo mecanismos que aumentam a atividade da eNOS. As estatinas são fármacos que possuem, dentre seus efeitos pleiotrópicos, a melhora na função do endotélio e na composição da HDL. Dada a importância tanto da expressão quanto da atividade da eNOS para a função endotelial, bem como dos efeitos pleiotrópicos das estatinas sobre estas duas variáveis, avaliamos os parâmetros bioquímicos e a composição das sub-frações de HDL (HDL2 e HDL3) após uso de placebo e atorvastatina em uma amostra populacional de 30 indivíduos, divididos em dois grupos: 15 indivíduos portadores do polimorfismo T-786C do gene da eNOS (CC) e 15 não portadores (TT). Duzentos indivíduos foram genotipados, e pareamos conforme idade e IMC 15 indivíduos TT e 15 indivíduos CC, que receberam placebo e/ou atorvastatina na dose de 10mg/dia, por 14 dias. Os parâmetros séricos analisados foram determinados através de métodos bioquímicos enzimáticos, radiométricos, nefelométricos e microultracentrifugação. Mediu-se lípides, lipoproteínas, composição das sub-frações da HDL (HDL2 e HDL3), apolipoproteínas, atividade da proteína de transferência de colesteril éster, metabólitos do NO e proteína C reativa. Após o uso da estatina, como esperado, drásticos efeitos redutores foram observados tanto nos lípides, lipoproteínas, apolipoproteínas e de forma independente do polimorfismo, além da redução de ácidos graxos livres nos portadores do genótipo CC. Nas sub-frações a relação lípides/proteínas foi reduzida tanto em HDL2 quanto em HDL3.O aumento da atividade da CETP nos portadores foi corrigido pela estatina e os níveis de ácidos graxos livres reduziram-se de maneira polimorfismo-dependente, em oposição à redução observada do nitrito, que foi polimorfismo-independente. usPCR e Lp(a) não se modificaram. A atorvastatina pode ter atuado sobre o transporte reverso de colesterol através da redução da atividade da lipase hepática e aumento de atividade da PLTP. Foram observadas interações genótipo/tratamento limítrofes para CETP e Lp(a). Estes resultados sugerem que o tratamento com estatinas pode ser relevante na prevenção primária da aterosclerose em portadores do polimorfismo, independentemente de modificações lipídicas séricas. Portanto estes indivíduos se beneficiariam com o uso de estatinas através da modulação da atividade da CETP e redução da concentração de ácidos graxos livres. / Abstract: Nitric oxide (NO) is produced in the vascular endothelium by endothelial nitric oxide synthase (eNOS), an enzyme negatively regulated by the presence of the T-786C polymorphism, leading to endothelial dysfunction. High-density lipoproteins (HDL) have well-established anti-atherogenic functions, for example mechanisms that enhance eNOS activity. Statins are drugs that have pleiotropic effects, such as the improvement in endothelial function and beneficial composition of HDL. Taking into account both the activity of eNOS on endothelial function, and the validity of the pleiotropic effects of statins, we evaluated the biochemical parameters and the composition of subfractions of HDL (HDL2 and HDL3) after use of placebo and atorvastatin at a dose of 10mg/day for 14 days, in a population sample of 30 individuals divided into two genotype groups of the T-786C polymorphism of the eNOS gene: CC (carriers) or TT (non-carriers). Two hundred individuals were genotyped, and the selected groups paired by age and BMI. The serum parameters analyzed were determined using biochemical enzymatic, radiometric, nephelometric and microultracentrifugation methods. We measured lipids, lipoproteins, the composition of sub-fractions of HDL (HDL2 and HDL3), apolipoproteins, activity of cholesteryl ester transfer protein, NO metabolites and hsCRP. After statin, as expected, drastic effects were observed both in lipids, lipoproteins, apolipoproteins, independently of the polymorphism. In HDL sub-fractions the ratio lipid/protein was smaller in both HDL2 and HDL3. CETP activity and free fatty acids were reduced in a polymorphism-dependent manner, and the reduction of nitrite was polymorphism-independent. hsCRP did not change. Atorvastatin may have acted on the reverse cholesterol transport by reducing the activity of hepatic lipase, increased PLTP activity and reducing CETP. There was a genotype/drug interaction effect on CETP and Lp(a). These results suggest that statin treatment may be relevant for primary prevention of atherosclerosis in patients with the polymorphism, irrespective of serum lipid changes. These individuals would benefit from the use of statins because of reduction of CETP activity and free fatty acids. / Mestrado / Ciencias Biomedicas / Mestre em Ciências Médicas

Made available in DSpace on 2014-10-09T12:28:04Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:23Z (GMT). No. of bitstreams: 0 / Este trabalho apresenta as propriedades ópticas dos complexos Európio Tetraciclinas (EuTcs) na presença de LDL e de LDL oxidada com potenciais aplicações em análises clínicas. Foram escolhidos quatro elementos da família das Tetraciclinas: Tetraciclina (Tc), Clorotetraciclina (CTc), Metatetraciclina (MTc) e Oxitetraciclina (OTc) para fazerem parte dos complexos com o íon európio. As melhores condições para se formar os complexos eficientemente foram determinadas, através das medidas dos parâmetros ópticos como: absorção, emissão e de tempo de vida. As melhores concentrações de európio nos complexos EuTcs e possíveis influências de íons inorgânicos normalmente presentes no plasma sanguíneo também foram analisadas. As amostras foram preparadas em pH neutro e a luminescência visível do lantanídeo foi detectada após tempo de repouso das amostras de 15 minutos. Os resultados deste trabalho mostraram que as moléculas de LDL e de LDL oxidada apresentaram um importante papel no aumento da intensidade de emissão dos complexos das Tcs. As medidas realizadas com os complexos EuTcs não apresentaram deslocamentos nos comprimentos de onda dos espectros de absorção e de emissão na presença de LDL, o que demonstra a ausência de interação direta entre as moléculas de Tcs e as moléculas de LDL e LDL oxidada. No entanto, o íon európio pode interagir em diferentes sítios das moléculas de tetraciclinas o que diferenciou a intensidade de emissão de cada complexo. Comparando os resultados obtidos entre os complexos de EuTcs, o complexo EuTc foi o que apresentou perspectivas promissoras na quantificação de LDL e LDL oxidada. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Dietary-derived lipoproteins, chylomicrons (CM) and CM remnants (CMR), have been implicated in the progression of cardiovascular disease. Retinyl esters are currently the most widely used method for monitoring CM metabolism. The availability, however, of a specific antisera to apo B-48, the protein uniquely associated with dietary-derived lipoproteins, has allowed more extensive investigation of CM and CMR metabolism. The effect of habitual, moderate levels of exercise (3 to 4 exercise sessions a week) on the lipaemic response to meals of varying fat content was assessed in young male subjects. Apo B-48, triacylglycerol (TAG) and retinyl ester were used as markers for CM particles. Active subjects had a lower response than an inactive group in all parameters measured over time after the meals. Lipoprotein lipase (LPL) activity levels measured at the end of the postprandial period were higher in the active group. The area under the time-response curves (AUC) for apo B-48 in the inactive group increased with increasing fat content of the meals, whereas the AUC for apo B-48 was the same after each meal in the active group. Validation of a specific ELISA for apo B-48 was carried out. Cross-reactivity of the antisera with low levels of apo B-100, the protein present on endogenous lipoproteins, was ruled out. The assay was specific and sensitive for measuring apo B-48 concentrations in the CM-enriched fractions. The use of the assay in the current format for plasma samples could not be fully assessed due to difficulties with isolating a pure, concentrated sample of apo B-100 and problems with reactivity between the secondary antibody used in the assay and plasma proteins. The assay was useful for showing postprandial patterns of changes in apo B-48 levels in plasma. The effects of meal frequency on the lipaemic response to a high fat test meal challenge were assessed in an intervention study. A nibbling diet was found to cause differences between the response of various parameters after the meal (NEFA-AUC, LPL activity, infranatant-TAG AUC and time to peak) compared with the normal meal frequency. The size and density distribution of CMR in plasma were investigated. Apo B-48 was found in the IDL and LDL fractions in both the postabsorptive and postprandial states. A comparison between the retinyl ester and apo B-48 responses in the postprandial studies showed that the time to peak retinyl ester level was delayed compared to apo B-48 and TAG. The importance of apo B-48 for studying the metabolism of CM and CMR metabolism was demonstrated.

M.Sc. (Biochemistry) / Dry eye disease (DED) and keratoconus (KC) continue to affect the quality of life of many South Africans (and elsewhere) and in the case of KC often leads to blindness. It is estimated that DED affects 14% to 33% of the population worldwide, while 1 in 2000 of the worlds population is affected by KC. However, details of the etiology of these diseases and their biochemical ‘fingerprint’ remain uncertain. In this study, emphasis was placed on the investigation of immunological proteins in the precorneal tear film of DED and KC subjects and meibomian lipids in these individuals. Tear fluid and meibum were collected from control, DED and KC volunteers. Control subjects were non-contact lens wearers and free from ocular diseases, whereas DED subjects were diagnosed by means of an ocular surface disease index (OSDI) questionnaire. DED subjects were divided into two groups: ‘moderate DED’ and ‘severe DED’ based on OSDI. KC subjects were diagnosed by the use of a slit-lamp biomicroscopy exam. Enzymelinked immunosorbent assays were performed to quantitate secretory immunoglobulin A (sIgA), tumour necrosis factor-alpha (TNF-á) and matrix metalloproteinase-1 (MMP-1) in the collected tear fluid. Meibum was analysed with proton nuclear magnetic resonance (1H-NMR) spectroscopy and Fourier transform infrared spectroscopy (FTIR). Multivariate data analyses (PCA) were used to extract interpretable information from the multidimensional data generated from the aforementioned techniques and used to build a broad picture of the general lipidomic differences between DED, KC and healthy subjects. Tear levels of sIgA and MMP-1 were significantly decreased in patients with KC compared to control. In contrast, the tears of severe DED subjects were characterised by higher levels of TNF-á and lower levels of sIgA. In subjects with moderate DED, TNF-á levels were significantly elevated. The results of this study re-emphasize that KC and DED individuals are associated with differential expression of specific tear proteins and support the view that the severity of DED is reflected in the levels of immunological proteins present in basal tears. Differences in the chemical composition of meibum from subjects with severe DED and KC compared to control were observed, more specifically in the aliphatic region of 1H-NMR spectra and C-C rocking region of FTIR spectra. The results therefore point towards the saturated components of fatty acids (and their chemical environments) as key targets for future investigations to elucidate compositional differences between DED, KC and healthy meibum.

Lipoprotein binding and metabolism in actively-dividing (subconfluent) and quiescent (postconfluent) bovine aortic endothelial cells (ECs) were qualitatively investigated by fluorescence microscopy using dioctadecylindocarbocyanine-labelled lipoproteins and by indirect immunofluorescence microscopy. LDL and acetylated-LDL (AcLDL) were seen bound to the surfaces of subconfluent ECs (at 4°C or at 37°C), as a random distribution of punctate foci. ECs therefore closely resembled fibroblasts in the distribution of LDL receptors on their surfaces. No binding of LDL was seen on postconfluent EC surfaces by either direct or indirect fluorescence microscopy. The patterns of AcLDL binding on postconfluent ECs resembled those on subconfluent ECs. Intracellular LDL and AcLDL occurred as perinuclear accumulations of large fluorescent disc-shaped profiles in subconfluent ECs. These accumulations were shown to arise from surface-bound material by pulse-chase experiments. Intracellular LDL was absent in the majority of postconfluent ECs, while AcLDL accumulation was massive. "Wounding" of cultures allowed simultaneous assessment of lipoprotein metabolism in quiescent and actively-dividing areas of the same culture. Quantitative assessments of the above-mentioned phenomena were made using ¹²⁵I-labelled lipoproteins. Receptor-mediated binding of LDL decreased five to ten-fold as the cultures modulated from subconfluent to postconfluent morphology. No receptor-bound LDL was detected in postconfluent ECs. Conversely, the amount of AcLDL bound increased at least fivefold during EC growth in parallel cultures. The amounts of lipoproteins endocytosed and metabolised were generally related proportionately to the amounts bound in each case. The distribution of LDL receptors on cultured cells was also investigated at the ultrastructural level using colloidal gold-conjugated LDL as a probe, and similarly labelled antibodies as probes. Whole-mounted cells with receptor probes bound to them were examined directly in the transmission electron microscope. The topographical distribution of LDL receptors has not been investigated by these techniques before. A novel method of preparing cytochemically-labelled, whole-mounted cells from styrene culture dishes was developed and used in this study. LDL Receptors expressed on the surfaces of human skin fibroblasts served to standardise these colloidal gold techniques and fortuitously led to new information on receptor distribution. Normal (FGo) and LDL receptor-negative mutant fibroblasts (GM 2000) acted as positive and negative controls respectively. Normal fibroblast LDL receptors were grouped into clusters consistent in size with coated pits (200 - 500 nm in diameter). A novel finding was the presence of a diffuse population of receptors scattered randomly amongst the clustered receptors. Another mutant fibroblast, GM 2408A, known to have an aberrant LDL receptor distribution, was also examined. Its receptors were shown to be dispersed singly, and in occasional groups of two and three, at random over the cell surfaces. No clusters were detected. The receptor-negative GM 2000 bound virtually no probes. While not as sensitive as the colloidal gold-conjugated LDL probe, an antireceptor monoclonal antibody (IgG-C7), localised by indirect immunogold labelling, gave similar results when applied to the above cells. This was taken as strong corroborative evidence that the LDL receptor distributions as determined by colloidal gold-conjugated LDL were correct. It is suggested that the dispersed population of receptors on normal fibroblasts may represent newly-emerged recycling receptors which have yet to cluster in coated pits. A further new finding reported here is the existence of the same two patterns of LD L receptors, dispersed and clustered, on the surface of subconfluent ECs. It was noted, from the study of whole-mounted and thin-sectioned cells, that the receptors were preferentially arranged in rings following the circumference of coated pit areas on the cell surface. Often these rings associated in groups or even coalesced into compound clusters. The significance of these groupings is not yet understood. In sharp contrast to the situation on subconfluent ECs, no LDL receptors (probed with the extremely sensitive colloidal-gold conjugated LDL) could be detected at the EM level on the surface of postconfluent ECs. Active cells in wounded postconfluent monolayers expressed abundant receptors detected at the EM level. It is concluded that postconfluent quiescent bovine aortic ECs in vitro metabolise virtually no LDL via the LDL-receptor pathway due to a vanishingly low number of LDL receptors. This contrasts with the ability of postconfluent cells to metabolise relatively large amounts of AcLDL via a receptor-mediated mechanism. The significance of these conclusions is discussed with respect to the interaction of plasma lipoproteins with the endothelium in vivo.

The expression of two phenotypically-contrasting LDL receptor mutations was characterized in cultured fibroblasts from the genetically-homozygous Afrikaner subjects, FH1a and lb, and FH3a and 3b, respectively. Surface receptor expression and functional activity were studied by ligand (¹²⁵I-LDL) and monoclonal antibody (¹²⁵I-IgG-C7) binding, and c35s]-methionine pulse-chase experiments were used to analyze biosynthesis, processing and degradation of IgG-C7- immunoprecipitable mutant receptors. Cells from the "receptor-negative" subjects, FH3a and 3b exhibited reduced, but significant (40-60% of normal) LDL receptor synthesis rates. Newly-synthesized precursors were processed slowly (t½ 1.5 hours versus normal t½ of approximately 15 minutes) to mature receptors which reached the cell-surface, but were rapidly degraded thereafter with a half-life of approximately 1.7 hours (normal value 12.6 hours) thus representing a new type of LDL receptor defect. Lysosomotropic weak bases such as ammonium chloride partially inhibited rapid degradation of the mutant receptors, suggesting the involvement of proteolysis in acidic compartments such as lysosomes or endosomes. Fibroblasts from FH1a and lb exhibited normal synthesis rates of LDL receptor precursors that were processed at a severely reduced rate (t½ approximately 5 hours) to functionally heterogeneous mature surface receptors. Onethird of the receptors (20% of normal levels) bound ¹²⁵I-LDL with normal affinity at 4°C and 37°C, whereas the majority were able to recognize only ¹²⁵I-IgG-C7, and apparently showed defective internalisation and subsequent degradation of the bound IgG-C7 at 37°C. The existence of the two receptor populations was further supported by selective intracellular trapping and degradation of only the active, LDL-binding population, in the presence of ammonium chloride and LOL. The abnormal form predominated even in newly-synthesized receptors and reached a maximum of 50-70% of normal levels after 48 hours of upregulation. Upregulation kinetics and degradation rates (t½ = 10-11 hours) of both functionally-active and abnormal receptor populations were similar to normal. A progressive increase in apparent molecular weight of the slowly-processed precursor receptors suggested a possible role for abnormal glycosylation in the formation of both "normal" and abnormal conformations of the same receptor molecule.

The rates of plasma clearance of human native low density lipoproteins (LDL) and acetylated human low density lipoproteins (acetyl-LDL) were compared between copper-deficient (CuD) and copper-adequate (CuA) rats. Purified human LDL (d 1.02-1.063) were labeled with 125I and injected to fasted recipient rats intravenously. At different time intervals plasma clearance of 125I radioactivity was measured. The percent of clearance was calculated based on the total plasma volume, as determined by a radioisotopic dilution method. Native human 125I-LDL were cleared at a faster rate in CuD, compared with CuA rats. The half-times (t 1 2) of 125I-LDL clearance are 4.90 ± 0.20 and 5.80 ± 0.30 hours in CuD and CuA rats, respectively. The plasma trichloroacetic acid-soluble 125I-radioactivity was significantly and steadily increased in CuD rats at each interval, reflecting the faster clearance and degradation of LDL in those rats. The plasma removal of 125I-acetyl-LDL was faster compared with that of 125I-LDL. The half-times (t 1 2) of acetyl-LDL in CuD and CuA rats are 5.20 ± 0.06 and 5.16 ± 0.08 minutes, respectively, with no significant difference between the groups. The data indicates that the uptake of LDL via the "scavenger" receptor remains unaffected in copper-deficient rats. The faster removal of the unmodified (native) LDL in CuD group suggests that the apoB,E receptor is up-regulated in copper-deficient rats and that the hypercholesterolemia observed in copper deficiency is not associated with the defective uptake of LDL by the apoB,E-receptor dependent mechanism.