Reactive oxygen species generation in peripheral blood monocytes and oxidized LDL are increased in hyperlipidemic patients.

OBJECTIVES: Experimental and in vitro evidences have established that reactive oxygen species (ROS) generated by vascular wall cells play a key role in atherogenesis. Here, we evaluated the rate of ROS generation by resting peripheral monocytes in naive hyperlipidemic subjects. DESIGN AND METHODS: Primary hypercholesterolemic, combined hyperlipidemic, and normolipidemic individuals were studied. ROS generation and the mitochondrial electrical transmembrane potential were estimated by flow cytometry. Plasma oxidized (ox) LDL levels and lipid profile were measured by ELISA and enzymatic colorimetric methods. RESULTS: Both hyperlipidemic groups presented significantly higher rates of monocyte ROS generation and elevated plasma levels of ox-LDL. Combined hyperlipidemic subjects presented increased levels of small dense LDL and insulin. Significant positive correlations between monocyte ROS generation and ox-LDL concentrations were found in pooled data. CONCLUSIONS: These data provide evidence that ROS production by circulating monocytes from hyperlipidemic subjects may contribute to the systemic oxidative stress and possibly to atherogenesis.

High-density lipoprotein subfractions in normolipidemic individuals without clinical atherosclerosis lipoprotein subfractions in an adult population.

This study evaluated the serum concentrations of lipids, lipoproteins, apolipoproteins, and high-density lipoprotein (HDL) subfractions in Brazilian adults. We analyzed the distribution of lipids in HDL2 and HDL3 in a normolipidemic population without evidence of established cardiovascular disease (CVD). A total of 93 males and 92 females, healthy and normolipidemic, volunteered to be submitted to a clinical examination, a blood collection, and to answer a questionnaire aimed at determining signs and symptoms of atherosclerotic disease. Their fasting plasma lipid, lipoproteins, apolipoproteins, and the cholesterol and triglyceride concentrations in HDL2 and HDL3, isolated by microultracentrifugation, were determined by enzymatic-colorimetric methods. The interpercentile intervals (2.5-97.5) for the population were established as being 5-18 mg/dL in men and 4-28 mg/dL in women for HDL2 cholesterol (HDL2chol) and 1-57 mg/dL in men and 2-61 mg/dL in women for HDL3 cholesterol (HDL3chol). HDL2 triglyceride levels (HDL2Tg) in men were 1-26 mg/dL and in women 2-28 mg/dL; moreover, the HDL3 triglyceride (HDL3Tg) intervals were established as 4-46 mg/dL for both sexes. The determination of reference ranges for lipids in HDL subfractions in populations without clinical atherosclerosis, is an useful tool for metabolic, diagnostic, and therapeutic approaches. We determined the intervals for HDL2chol, HDL3chol, HDL2Tg, and HDL3Tg. There were variations with sex and/or age for HDL2chol, HDL3chol, and HDL2Tg in the studied population.

Sex-dependent variables in the modulation of postalimentary lipemia.

OBJECTIVE: To quantify in young adults the sex-dependent differences in lipemic responses to a fat meal, we measured the association of these responses with markers of atherosclerosis and determined their metabolic regulators. METHODS: Forty-nine normolipidemic volunteers, 25 women and 24 men, were matched according to age, body mass index, waist circumference, diet, physical activity, and apolipoprotein-E phenotyping. After receiving a standardized fat meal (40 g of fat/m2 of body surface area), serial blood samples were drawn for laboratory analysis. Common carotid intima-media thickness was measured. RESULTS: The lipemic responses were much greater in men than in women for plasma triacylglycerol (TAG), cholesterol, and TAG in TAG-rich lipoproteins, non-esterified fatty acids, phospholipids, and apolipoprotein-B100. Men presented with increased blood pressure, carotid intima-media thickness, TAG, hepatic lipase, and insulin and lower high-density lipoprotein cholesterol, apolipoprotein-AI, and non-esterified fatty acid concentrations. Only in men did carotid intima-media thickness correlate marginally with titers of autoantibodies to epitopes of oxidized low-density lipoprotein; in addition, phospholipids and cholesteryl esters were negatively related to autoantibodies. Multivariate analysis indicated that age (R2 = 45%), waist circumference (R2 = 19%), phospholipids (R2 = 39%), non-esterified fatty acids (R2 = 29%), insulin (R2 = 17%), lipoprotein lipase activity (R2 = 16%), and cholesteryl ester transfer protein (an exploratory variable; R2 = 6%) are strong determinants of postalimentary lipemia in women and that only insulin (R2 = 55%) and phospholipids (R2 = 37%) are determinants in men. CONCLUSIONS: We have provided data explaining that postalimentary lipemia is differently regulated by sex. Several risk factors for coronary heart disease and significant associations with atherosclerosis biomarkers were found only in men.

Biological rhythms of biochemical serum parameters in a Brazilian population: a three-year study.

A marked decrease in analytical and post-analytical variability has been achieved in clinical laboratories by the use of automated analytical systems. Current studies are now focused on the origin of pre-analytical variability, such as that due to intra-individual differences and biological rhythms. The objective of this work was to evaluate the occurrence of biological rhythms in several biochemical serum parameters in a Brazilian population. A retrospective study (1996 to 1998) was carried out to collect the test results within the reference intervals of adults, from 21 to 50 yr of age (average age of 36 yr) attending the outpatient clinics of the Teaching Hospital at the University of Campinas, São Paulo, Brazil. The reference sample was 52.9% male and 47.1% female and encompassed 15,036 calcium, 7,478 phosphorus, 53,641 urea, 58,315 creatinine and 6,433 uric acid determinations (140,903 in total). Significant annual rhythms were detected in serum calcium (p

High frequency of Fredrickson's phenotypes IV and IIb in Brazilians infected by human immunodeficiency virus.

BACKGROUND: Human immunodeficiency virus (HIV) infection is very prevalent in Brazil. HIV therapy has been recently associated with coronary heart disease (CHD). Dyslipidemia is a major risk factor for CHD that is frequently described in HIV positive patients, but very few studies have been conducted in Brazilian patients evaluating their lipid profiles. METHODS: In the present work, we evaluated the frequency and severity of dyslipidemia in 257 Brazilian HIV positive patients. Two hundred and thirty-eight (93%) were submitted to antiretroviral therapy (224 treated with protease inhibitors plus nucleoside reverse transcriptase inhibitors, 14 treated only with the latter, 12 naive and 7 had no records of treatment). The average time on drug treatment with antiretroviral therapy was 20 months. None of the patients was under lipid lowering drugs. Cholesterol, triglyceride, phospholipid and free fatty acids were determined by enzymatic colorimetric methods. Lipoprotein profile was estimated by the Friedewald formula and Fredrickson's phenotyping was obtained by serum electrophoresis on agarose. Apolipoprotein B and AI and lipoprotein "a" were measured by nephelometry. RESULTS: The Fredrickson phenotypes were: type IIb (51%), IV (41%), IIa (7%). In addition one patient was type III and another type V. Thirty-three percent of all HIV+ patients presented serum cholesterol levels >or= 200 mg/dL, 61% LDL-cholesterol >or= 100 mg/dL, 65% HDL-cholesterol below 40 mg/dL, 46% triglycerides >or= 150 mg/dL and 10% have all these parameters above the limits. Eighty-six percent of patients had cholesterol/HDL-cholesterol ratio >or= 3.5, 22% increased lipoprotein "a", 79% increased free fatty acids and 9% increased phospholipids. The treatment with protease inhibitors plus nucleoside reverse transcriptase inhibitors increased the levels of cholesterol and triglycerides in these patients when compared with naïve patients. The HDL-cholesterol (p = 0.01) and apolipoprotein A1 (p = 0.02) levels were inversely correlated with the time of protease inhibitor therapy while total cholesterol levels had a trend to correlate with antiretroviral therapy (p = 0.09). CONCLUSION: The highly varied and prevalent types of dyslipidemia found in Brazilian HIV positive patients on antiretroviral therapies indicate the urgent need for their early diagnosis, the identification of the risk factors for CHD and, when needed, the prompt intervention on their lifestyle and/or with drug treatment.

Phospholipid transfer protein activity in two cholestatic patients.

CONTEXT: Plasma phospholipid transfer protein mediates the transfer of phospholipids from triglyceride-rich lipoproteins, very low density lipoproteins and low density lipoproteins to high density lipoproteins, a process that is also efficient between high density lipoprotein particles. It promotes a net movement of phospholipids, thereby generating small lipid-poor apolipoprotein AI that contains particles and subfractions that are good acceptors for cell cholesterol efflux. CASE REPORT: We measured the activity of plasma phospholipid transfer protein in two cholestatic patients, assuming that changes in activity would occur in serum that was positive for lipoprotein X. Both patients presented severe hypercholesterolemia, high levels of low density lipoprotein cholesterol and, in one case, low levels of high density lipoprotein cholesterol and high levels of phospholipid serum. The phospholipid transfer activity was close to the lower limit of the reference interval. To our knowledge, this is the first time such results have been presented. We propose that phospholipid transfer protein activity becomes reduced under cholestasis conditions because of changes in the chemical composition of high density lipoproteins, such as an increase in phospholipids content. Also, lipoprotein X, which is rich in phospholipids, could compete with high density lipoproteins as a substrate for phospholipid transfer protein.

Phospholipid transfer protein activity in two cholestatic patients

CONTEXTO: A proteína de transferência de fosfolípides é responsável pela transferência de fosfolípides de lipoproteínas ricas em triglicérides, as lipoproteínas de muito baixa densidade e também para lipoproteínas de baixa densidade para as lipoproteínas de alta densidade, processo este também bastante eficiente entre partículas de lipoproteínas de alta densidade. Esta proteína promove a transferência líquida de fosfolípides gerando partículas pequenas, pobres em apolipoproteínas AI, subfrações estas que são excelentes aceptoras de efluxo celular de colesterol. CASE REPORT: A atividade da proteína de transferência de fosfolípides foi avaliada em dois pacientes com colestase hepática assumindo-se que alterações na sua atividade possam ocorrer em plasma de pacientes que apresentam lipoproteína X. Ambos pacientes apresentavam grave hipercolesterolemia, altos níveis de colesterol nas lipoproteínas de baixa densidade e fosfolípides e, em um deles, baixos níveis de colesterol em lipoproteínas de alta densidade. A atividade da proteína de transferência de fosfolípides detectada em ambos encontrava-se no limite inferior. Não são de nosso conhecimento resultados semelhantes na literatura. Nossa hipótese seria a de que a atividade da proteína de transferência de fosfolípides estaria reduzida na colestase hepática devido a alterações na composição química das lipoproteínas de alta densidade, como por exemplo, aumento de fosfolípides da partícula. A lipoproteína X, rica em fosfolípides, também poderia competir com a lipoproteína de alta densidade como substrato para a ação da proteína de transferência de fosfolípides.

Effect of atorvastatin on ApoE and ApoC-I synthesis and secretion by THP-1 macrophages.

Apolipoprotein (apo) E and C-I are plasma apolipoproteins that have been implicated in the etiology of atherosclerosis and obesity, respectively. Both proteins are synthesized and secreted by macrophages, though pharmacological regulation of their production is poorly understood. The authors compared the effect of 2 HMG-CoA reductase inhibitors, atorvastatin and cerivastatin, on the synthesis and secretion of apoE and apoC-I by THP-1 macrophages. Atorvastatin reduced medium apoE and cellular apoE mRNA of PMA-activated THP-1 cells in a dose-dependent manner (-24% and -22%, respectively, at 1-micromol/L, P < 0.01). ApoC-I in the medium was also reduced by atorvastatin in a dose-dependent manner, though to a lesser extent (-15% at 1-micromol/L, P < 0.05). Cerivastatin similarly reduced medium apoE (-20% at 1-micromol/L, P < 0.05) and cellular apoE mRNA (-31% at 1-micromol/L, P < 0.05), and significantly lowered cellular apoC-I mRNA (-15%, P < 0.05), but not apoC-I in the medium. In experiments with THP-1 macrophages loaded with cholesterol (ie, 24-hour incubation with acetyl-LDL), atorvastatin and cerivastatin (1-micromol/L) significantly (P < 0.05) reduced both medium apoE (-30% and -25%, respectively) and cellular apoE mRNA (-25% and -17%, respectively). A lower and less consistent effect was observed on medium apoC-I (-6% and -18%, respectively) and cellular apoC-I mRNA (-13% and -19%, respectively). These data demonstrate that statins have the capacity to reduce the synthesis and secretion of both apoE and apoC-I in THP-1 macrophages loaded or unloaded with cholesterol.

Frutosamina: uma revisäo dos últimos dez anos / Fructosamine: a review for the last ten years

A manutençäo da taxa de glicose sanguínea täo próxima quanto possível dos níveis normais tem sido amplamento aceita como um bom índice de acompanhamento, podendo reduzir significativamente as sequelas do diabetes. Medidas diárias múltiplas da glicemia näo säo frequentemente um caminho prático no controle do diabético, embora pudessem ser consideradas como o melhor método de controle. Durante a década de 70, diversas técnicas para a mensuraçäo das hemoglobinas glicadas tornaram-se acessíveis à grande maioria dos laboratórios, fornecendo uma indicaçäo retrospectiva dos níveis de glicose sanguínea das últimas quatro semanas e têm sido largamente adotadas como uma maneira usual deste mesmo controle diabético. A maioria das técnicas tentam medir a HbAIc, originalmente descrita como a mais abundante das fraçöes glicadas da hemoglobina que se encontram aumentadas nos diabéticos. Durante a última década vários métodos foram desenvolvidos para mensurar outras proteínas glicadas além da HbAIc. A descoberta de que outras proteínas séricas säo glicadas em caminhos análogos ao da hemoglobina despertou muito interesse quanto à sua aplicaçäo clínica. A albumina glicada tem sido indicada como um índice para o controle glicêmico num tempo de duas, três semanas, um período menor do que o da hemoglobina glicada, mas suficiente para ser adotada como controle

Radiografia do esôfago, estômago e duodeno em cäes / Radiography of oesophagus, stomach and duodenum of dogs

Realizaram-se exames radiográficos contrastados do esôfago, estômago e duodeno, utilizando-se o sulfato de bário comercial sem diluir, em 20 animais da espécie canina, clinicamente sadios. Mostrou-se a importância do jejum de 18 horas de alimentos sólidos e de seis horas de líquidos, como preparativos. Utilizaram-se as incidências ventro-dorsal e látero-lateral. O meio de contraste evidenciou muito bem a conformaçäo anatômica dos órgäos estudados

Determinaçao das frutosaminas sericas por colorimetria: comparaçao entre a tecnica manual e a semi-automatizada em ABA-100 / Colorimetric determination of serum fructosamine: comparison of the manual and automated (ABA-100) assays

A determinaçao das frutosaminas sericas e um parametroadicional de grande importancia no controle dadiabetes, permitindo o monitoramento do estado glicemico do paciente nas duas ultimas semanas. Sua qualificaçao porcolorimetria tem sido feita atraves da reduçao do azul denitrotetrazolio (NBT), empregando-se normalmente como padraoo 1-deoxi-1-morfolino frutoso (DMF) em soluçao aquosa debumina a 4%. Nosso objetivo foi comparar os resultados das frutosaminas sericas por metodos colorimetrico cinetico manual e semi-automatizado, utilizando-se neste ultimo,alem do DMF, um padrao secundario de soro humano de concentraçao conhecida. A glicemia foi determinada pelo metodo da hexoquinase o observamos no tratamento estatistico que os metodos para a determinaçao das frutosaminas sao semelhantes quando utilizamos dois tipos de padroes no semi-automatizado.

Mucoproteínas: novas contribuiçoes para um problema laboratorial / Mucoproteins: new assessments for a laboratorial problem

O objetivo do presente trabalho foi avaliar a influência da concentraçäo do ácido perclórico e da temperatura de desproteinizaçäo, na determinaçäo das mucoproteínas séricas. Como o doseamento das mucoproteínas possui importância clínica no acompanhamento de doenças infecciosas e de vários distúrbios metabólicos, exige-se, desta forma, um controle minucioso de fatores externos que possam interferir na sua quantificaçäo.

Avaliaçäo crítica da interferência da bilirrubina na dosagem de creatinina sérica pela reaçäo de Jaffé / Critical evaluation of bilirubin interference in the Jaffé reaction for serum creatinine determination

Estudamos a deteminaçäo da creatinina em "pools" de soro (normal e alterado) acrescidos de quantidades conhecidas de bilirrubina e também em soros ictéricos de pacientes, através da reaçäo de Jaffé, utilizando os métodos de ponto-final e cinético. Verificamos a interferência negativa da bilirrubina na dosagem cinética de creatinina, que näo foi observada na reaçäo de ponto-final. A reaçäo cinética, entretanto, pode ser utilizada em soros ictéricos desde que haja uma inversäo da ordem de adiçäo dos reagentes, com pré-incubaçäo das amostras com NaOH 0,5 N

Dosagem de creatinina: fatores de erro na reação de Jaffé / Creatinine dosage: error factors in the Jaffé Reaction

Estudamos o mecanismo da reação de Jaffé para a determinação da creatinina humana, utilizando os métodos cinético e ponto-final. Foi analisada a magnitude de interferência nas constantes físicas (tempo e temperatura de incubação) e no equilíbrio da reação, obtendo-se valores subestimados a 25'C nos 2 métodos estudados. Os resultados a 30'C são coerentes com os valores de referência descritos na literatura. A hiperglicemia interfere mais significativamente na reação de ponto-final, elevando os resultados de creatinina a partir de 290 mg%. O método cinético mostrou-se bastante eficaz na dosagem da creatinina sérica discriminando valores sem interferência de substâncias redutoras e com reprodutibilidade compatível às melhores técnicas laboratoriais (AU).

Efeito da hidroclorotiazida e metildopa sobre o metabolismo lipídico em hipertensos essenciais

Os beneficios do tratamento da hipertensäo leve estäo sujeitos a controvérsias, tendo surgido questöes sobre efeitos colaterais dos anti-hipertensivos influenciando desfavoravelmente estes resultados, principalmente em relaçäo a distúrbios do metabolismo lipídico. Foram analisados comparativamente os efeitos a médio prazo (16 semanas) da hidroclorotiazida (HCTZ) e metildopa (MD) sobre lípides e lipoproteínas plasmáticas em 22 hipertensos essenciais leves ou moderados com hipercolesterolemia e/ou hipertrigliceridemia após quatro semanas de placebo. Verificou-se queda transitória de triglicérides e beta-lipoproteínas no período de tratamento com MD e alfa-lipoproteínas com HCTZ. Näo se alteraram colesterol e triglicérides com HCTZ. Conclui-se que a HCTZ e MD näo induziram modificaçäo no metabolismo lipídico durante o período estudado

Tratamiento da hiperlipidemia primária com ácido 5-metil-pirazina-2-carbocilico (acipimox) / Treatment of primary hyperlipidemia with 5-methylpyrazinecarboxylic acid (acipimox)

Após período controle de 2 meses, 14 pacientes hiperlipidêmicos foram tratados com acipimox (geralmente 750 mg/dia) durante aproximadamente 12 meses. Ocorreu reduçäo média de colesterolemia de 17%, sem que diminuisse significantemente a trigliceridemia, exceto nos casos de hipertrigliceridemia acima de 600 mg/100 ml. Por outro lado a colesterolemia descreveu 23% nos casos de hiperlipidemia combinada (hipercolesterolemia com hipertrigliceridemia), mas apenas 13% nos casos de hipercolesterolemia isolada. Houve diminuiçäo porcentual das beta-lipoproteínas de 49,3% para 43,5% com simultâneo aumento desejável das alfa-LP de 18,5% para 25,9%, mas as pré-beta-LP ficaram estáveis. O incremento de uricemia foi de 13,7%, porém a glicemia, os testes orais de tolerância à glicose, a funçäo hepática e a renal näo se alteraram. Efeitos colaterais foram despresíveis e a tolerância foi consideravelmente melhor do que aquela atribuída ao ácido nicotínico