Blood and plasma glutathione measured in healthy subjects by HPLC: relation to sex, aging, biological variables, and life habits

We report an HPLC method for measuring the concentrations of reduced (GSH) and total (GSHt) free glutathione in human plasma and whole blood. The chromatographic step was coupled with a postcolumn derivatization reaction and fluorometric detection. The linear range was 0.81-13.02 mumol/L, and the detection limit was 0.13 mumol/L. In healthy adults (ages 18-73 years), mean concentrations were 941 +/- 155 mumol/L for GSHt and 849 +/- 63 mumol/L for GSH in blood (107 men, 94 women), and 3.39 +/- 1.04 mumol/L for GSH in plasma (66 men, 58 women). Blood GSHt but not GSH was significantly lower in children (32 boys, 32 girls: 872 +/- 157 mumol/L) than in adults. Blood GSHt and GSH appeared to be correlated positively with the number of cigarettes smoked per day and the regular practice of physical exercise, and negatively with alcohol abstinence. We observed positive correlations between blood GSHt and cholesterol and calcium concentrations, and between blood GSH and cholesterol concentration.

Apolipoprotein E: an important gene and protein to follow in laboratory medicine

The human apolipoprotein (apo) E gene is polymorphic, with three common alleles (epsilon 2, epsilon 3, epsilon 4) coding for three isoforms (E2, E3, E4). The isoforms differ from each other by a single amino acid substitution, and also differ in their binding affinity for the four apo E receptors. Apo E polymorphism is an important determinant of risk for the development of cardiovascular and Alzheimer diseases, the prevalence of the epsilon 4 allele being increased in both kinds of patients compared with control subjects. Furthermore, the prevalence of the epsilon 4 allele differs among populations (range 5-40%, respectively, for Taiwanese and Papua New Guineans). Genotyping or phenotyping needs to be introduced in clinical laboratories. The choice of the method should be based on the types of patients who are examined. The apo E genotype is also a determinant of apo E plasma concentration. Standardization of apo E measurement is an important prerequisite before investigating the clinical interest of plasma apo E concentration. Determination of apo E genotype/phenotype and later the plasma concentration are expected to yield useful clinical laboratory information.

Segregation analysis and variance components analysis of bone mineral density in healthy families

Bone mineral density (BMD) was measured in 1992-93 in 129 nuclear families, including 258 parents and 183 children, and was analyzed for familial resemblance factors. BMD measurements were adjusted on weight and age. Segregation analysis rejected the monogenic hypothesis and exhibited a strong polygenic component. Variance components analysis was then used to estimate the parameters of a multivariate normal model including an additive polygenic component, a common environment factor, and a residual specific to each individual. The genetic component was independent of sex and age. The common environmental factor was not significant. The variance of the residual specific factor appeared to be a quadratic function of age, reaching its minimum value at 26.4 years. Consequently, the maximum value for heritability (ratio of genetic variance to total variance) is observed at this age (h2 = 0.84). According to this model, the correlation between two relatives is a function of the ages of each individual in the pair.

The UDP glucuronosyltransferase gene superfamily: suggested nomenclature based on evolutionary divergence

A nomenclature system for the UDP glucuronosyltransferase superfamily is proposed, based on divergent evolution of the genes. A total of 26 distinct cDNAs in five mammalian species have been sequenced to date. Comparison of the deduced amino acid sequences leads to the definition of two families and a total of three subfamilies. For naming each gene, we propose that the root symbol UGT for human (Ugt for mouse), representing "UDP glucuronosyltransferase," be followed by an Arabic number denoting the family, a letter designating the subfamily, and an Arabic numeral representing the individual gene within the family or subfamily (hyphen before the Arabic number for mouse), e.g., human UGT2B1 and murine Ugt2b-1. Whereas the gene and cDNA should be italicized, the corresponding transcript, protein, and enzyme activity should not be written with lowercase letters or in italics, e.g., human or murine UGT2B1. Recent experimental evidence suggests that several exons of the UGT1 gene might be shared, indicating that distinct UGT1 transcripts and proteins may arise via alternative splicing; the gene and gene product of alternative splicing will be designated with an asterisk, e.g., UGT1*6 and UGT1*6, respectively. When an orthologous gene between species cannot be identified with certainty, as occurs in the UGT2B subfamily, we recommend sequential naming of the genes chronologically as they become characterized. We suggest that the human nomenclature system be used for species other than the mouse. We anticipate that this UGT gene nomenclature system will require updating on a regular basis.

Decreased high-density lipoprotein cholesterol and serum apolipoprotein AI concentrations are highly correlated with the severity of Alzheimer's disease

Serum apolipoprotein (apo) AI concentration was studied in 98 Alzheimer's disease (AD) patients (77.56+/-8.83 years) and 59 healthy, elderly controls (75.37+/-5.27 years). ApoAI levels were significantly lower (p<10(-7)) in AD patients. An apoAI cutoff value of 1.50 g/L, could distinguish between the two groups with a sensitivity of 71% and a specificity of 69%. ApoAI levels were highly correlated with mini-mental state (MMSE) scores of patients (p<0.0001). These relationships remained significant after adjustment for multiple testing. Our findings raise the question of the potential implication of apoAI in the etiopathology of AD and bring serum apoAI concentration to the fore as an important biochemical marker.

A multilocus genotyping assay for candidate markers of cardiovascular disease risk

A number of chronic diseases, including cardiovascular disease, appear to have a multifactorial genetic risk component. Consequently, techniques are needed to facilitate evaluation of complex genetic risk factors in large cohorts. We have designed a prototype assay for genotyping a panel of 35 biallelic sites that represent variation within 15 genes from biochemical pathways implicated in the development and progression of cardiovascular disease. Each DNA sample is amplified using two multiplex polymerase chain reactions, and the alleles are genotyped simultaneously using an array of immobilized, sequence-specific oligonucleotide probes. This multilocus assay was applied to two types of cohorts. Population frequencies for the markers were estimated using 496 unrelated individuals from a family-based cohort, and the observed values were consistent with previous reports. Linkage disequilibrium between consecutive pairs of markers within the apoCIII, LPL, and ELAM genes was also estimated. A preliminary analysis of single and pairwise locus associations with severity of atherosclerosis was performed using a composite cohort of 142 individuals for whom quantitative angiography data were available; evaluation of the potentially interesting associations observed will require analysis of an independent and larger cohort. This assay format provides a research tool for studies of multilocus genetic risk factors in large cardiovascular disease cohorts, and for the subsequent development of diagnostic tests.

Association of the G-2548A polymorphism in the 5' region of the LEP gene with overweight

Mutations in the translated part of the leptin gene (LEP) have been found in only two families. Nevertheless DNA polymorphisms in the LEP region are linked to extreme obesity. We previously found in the 5' region of LEP a polymorphism, G-2548A, associated with a differerce in BMI reduction following a low calorie diet in overweight women. Recently, this polymorphism was associated with extreme obesity in women. In this work, we genotyped a new sample from the general population including 314 normal weight (BMI < 27 kg/m2) and 109 overweight subjects (BMI > or = 27 kg/m2). The genotype and allele frequencies were significantly different between groups, with the G-2548 allele being more frequent in the overweight subjects (p < 0.01). In men, carriers of this allele had lower leptin concentrations adjusted for fat mass (p = 0.05). Our results indicate that variations at the leptin locus are associated with common obesity phenotypes, and not only with extreme obesity or the rare mendelian obesity syndromes.

Intima-media thickness and diameter of carotid and femoral arteries in children, adolescents and adults from the Stanislas cohort: effect of age, sex, anthropometry and blood pressure

OBJECTIVES

To study carotid and femoral intima-media thicknesses and diameters in relation to age, sex, morphologic status and blood pressure.

PARTICIPANTS

The subjects were 369 men and women (aged 10-54 years) from the Stanislas cohort, with no known cardiovascular disease.

METHODS

Intima-media thicknesses and diameters were measured by B-mode ultrasonography. The effects of sex, age, smoking, anthropometric variables, cholesterol and blood pressure were studied using bivariate and regression analysis.

RESULTS

Carotid and femoral intima-media thicknesses were not affected by age nor by sex up to 18 years of age. Thereafter, they increased sharply in men and remained higher than in women. Values were correlated with systolic blood pressure only in men, and with fat-free mass in children and young adults only at the femoral site. Smoking, body mass index and fat mass were associated with intima-media thicknesses only in adults. Carotid diameter was little affected by age during childhood and in adults. Femoral diameter increased up to the age of 18 in both sexes and remained unaffected by age thereafter. This increase was more pronounced in boys, and so values became consistently greater in males aged over 14 years. Carotid diameter was correlated with body mass index or fat mass whereas femoral diameter was correlated with weight or fat-free-mass in children and men. The opposite was observed in women.

CONCLUSION

Sex differences occur before adolescence for arterial diameter, but only at an adult age for intima-media thickness. In young subjects, carotid geometry seems to be influenced by blood pressure and excess body weight, while femoral artery geometry seems to be related to blood pressure and body growth.

Increased levels of apolipoprotein D in cerebrospinal fluid and hippocampus of Alzheimer's patients

Apolipoprotein D (apoD) is a member of the lipocalin family of proteins. Most members of this family are transporters of small hydrophobic ligands, although in the case of apoD, neither its physiological function(s) nor its putative ligand(s) have been unequivocally identified. In humans, apoD is expressed in several tissues, including the CNS, and its synthesis is greatly increased during regeneration of rat peripheral nerves. As apoD may have an important function in the nervous system and, particularly, in nerve regeneration, we measured immunoreactive apoD levels in the hippocampus and in CSF of patients with either Alzheimer's disease (AD) or other neuropathologies. In parallel, we determined the concentrations of apolipoprotein E (apoE), another apolipoprotein also implicated in nerve regeneration and in the etiology of AD. Levels of apoD but not apoE were increased in the hippocampus of AD patients compared with controls. ApoD concentrations, as determined by radioimmunoassay, were significantly increased in the CSF of AD patients (4.23 +/- 1.58 microg/ml) and patients with other pathologies (3.29 +/- 1.35 microg/ml) compared with those in the CSF of normal subjects (1.15 +/- 0.71 microg/ml). Although the differences were smaller than for apoD, the mean apoE concentrations in the CSF of both groups of patients were also significantly higher than those of controls. In AD patients, apoD, but not apoE, levels in CSF and hippocampus increased as a function of inheritance of the epsilon4 apoE allele. This study therefore demonstrates that increased apoD levels in the hippocampus and in CSF are a marker of neuropathology, including that associated with AD, and are independent of apoE concentrations.

Diet, antioxidant status, and smoking habits in French men

The aim of this study was to assess the association between smoking, food consumption, and antioxidant vitamin intake and plasma indexes of oxidative stress and antioxidant defenses in French adults. Food and nutrient intakes of 459 healthy men aged 23-57 y were estimated by the diet history method and analyzed by smoking status. Plasma alpha-tocopherol, ascorbic acid, and carotenoids were measured as antioxidants and malondialdehyde, protein Schiff bases, and autoantibodies against malondialdehyde-protein adducts as oxidative stress indexes. Smokers ate less fruit and vegetables than nonsmokers, leading to lower vitamin E, vitamin C, and carotene intakes, even after adjustment for age, education, and marital status. Unlike vitamin E, plasma ascorbic acid and beta-carotene concentrations were reduced in smokers compared with nonsmokers and were inversely related to cigarette consumption. This difference remained significant after adjustment for alcohol and dietary intakes. Among the measured oxidative stress indexes, only Schiff base concentration was positively related to the number of cigarettes smoked. In our sample of French men, smoking had an adverse effect on antioxidant status; vitamin intakes were reduced in smokers and plasma antioxidant indexes were altered independently of dietary intakes. As in other countries, in France smokers require particular attention in terms of public health intervention.

Drug metabolizing enzymes in the brain and cerebral microvessels

Several families of brain parenchyma and microvessel endothelial cell enzymes can metabolize substrates of exogenous origin. This xenobiotic metabolism includes functionalization and conjugation reactions and results in detoxication, but also possibly in the formation of pharmacologically active or neurotoxic products. The brain is partially protected from chemical insults by the physical barrier formed by the cerebral microvasculature of endothelial cells, which prevents the influx of hydrophilic molecules. These cells provide also, as a result of their drug-metabolizing enzyme activities, a metabolic barrier against penetrating lipophilic substances. The involvement of these enzymatic activities in neurotoxic events, probably responsible for neuronal dysfunctioning and/or death, neurodegenerative diseases and normal aging, is discussed.

Effect of alcohol consumption on blood antioxidant nutrients and oxidative stress indicators

The effects of alcohol consumption on plasma concentrations of antioxidant vitamins (alpha-tocopherol and ascorbic acid), selenium, and markers of oxidative stress, especially malondialdehyde (MDA) and autoantibodies directed to MDA adducts to proteins (Ig-NH2-MDA) were investigated in a large population of 417 supposedly healthy men who consumed only low or moderate amounts of alcohol as compared with 102 alcoholic patients without severe liver disease, who were studied both before and after 21 d of withdrawal treatment. Plasma concentrations of alpha-tocopherol, ascorbic acid, and selenium were lower in alcoholics than in men who drank low amounts of alcohol (P < or = 0.001), whereas MDA and Ig-NH2-MDA were higher (P < or = 0.001). Plasma concentrations of alpha-tocopherol and selenium remained unchanged after the withdrawal period, whereas ascorbic acid (P < or = 0.01), MDA, and Ig-NH2-MDA concentrations decreased (P < or = 0.001). Adjustment of data for circulating lipids and nutritional intake suggests a specific effect of alcohol on antioxidant vitamins, independent of nutritional status.

Wine, beer, and mortality in middle-aged men from eastern France

OBJECTIVE

To evaluate prospectively the health risk of wine and beer drinking in middle-aged men in the area of Nancy, France.

DESIGN

Prospective cohort study.

SUBJECTS

A total of 36 250 healthy men who underwent comprehensive health appraisals in a center of preventive medicine between January 1, 1978, and December 31, 1983.

MAIN OUTCOME MEASURES

Education, professional and leisure activities, and smoking and drinking habits were evaluated using a questionnaire. Blood pressure and mean corpuscular volume and gamma-glutamyltransferase, glucose, and serum cholesterol levels were routinely measured, and electrocardiography was routinely performed. We recorded mortality from all causes and specific causes during a 12- to 18-year follow-up across categories of baseline alcohol consumption.

RESULTS

Of the subjects, 28% drank beer, 61% drank wine but no beer, and 11% were abstainers; there was not much difference between social classes. During the follow-up, 3617 subjects died. The relative risk of death was estimated by the Cox proportional hazards model using nondrinkers as the reference and adjusting for 4 or 5 covariables. Moderate intake of both wine and beer was associated with lower relative risk for cardiovascular diseases; the risk was more significant with the intake of wine. For all-cause mortality, only daily wine intake (22-32 g of alcohol) was associated with a lower risk (0.67; 95% confidence interval, 0.58-0.77; P<.001) due to a lower incidence of cardiovascular diseases, cancers, violent deaths, and other causes.

CONCLUSION

In eastern France, moderately drinking only wine was associated with a lower all-cause mortality, although drinking both wine and beer reduced the risk of cardiovascular death.

Dietary intakes, eating style and overweight in the Stanislas Family Study

OBJECTIVES

To describe the eating patterns of members of French families and to assess the relationships between dietary intakes, eating style and overweight.

DESIGN

Cross-sectional analysis of nutritional and behavioural characteristics.

SUBJECTS

1,320 members of 387 families (age 11-65y) attending the Centre for Preventive Medicine for a routine medical check-up.

MEASUREMENTS

Individual body weight and height were measured. Food intake was assessed using a three day dietary record. Eating style was measured using the French validated version of the Dutch Eating Behaviour Questionnaire.

RESULTS

In each of the four groups (men, women, boys and girls), dietary restraint was positively correlated with overweight (P< or =0.001) and associated with lower energy intakes (P < or = 0.05-P < or = 0.001). A negative association between energy intake and overweight was found in girls only (P< or =0.001). In all cases, overweight and dietary restraint exaggerated any existing macronutrient imbalance in energy intake (ie higher protein and fat contributions, lower carbohydrate contribution). Emotional eating was positively correlated to body mass index in women only (P< or =0.01). External eating was mainly a characteristic of children (P< or =0.001).

CONCLUSION

As in overweight subjects, clear relationships were found in this sample of general population between dietary intakes and eating style. The population will be followed up for 10y. In the long term, these results should have implications in the prevention of obesity.

IL-6, TNF-alpha and atherosclerosis risk indicators in a healthy family population: the STANISLAS cohort

There are no satisfactory data on circulating concentrations of inflammatory cytokines and their potential relationship with traditional and nontraditional atherosclerosis risk factors in a large healthy young population. The present study was conducted to examine, in 179 healthy families selected from the STANISLAS cohort, the association between interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), C-reactive protein (CRP), orosomucoid, haptoglobin, cell-adhesion molecules (ICAM-1, E-, L- and P-selectin) and lipid parameter concentrations. Age, BMI, white blood cells and tobacco consumption contributed to the variation of IL-6 concentrations. Age and tobacco contributed also to TNF-alpha variation. Taking into account potential covariates, we showed strong positive correlation between IL-6 and both inflammatory markers TNF-alpha and CRP in parents and in offspring (P<0.001). In parents, IL-6 was associated with ICAM-1 and L-selectin (P<0.01), while IL-6 and TNF-alpha predicted E-selectin in offspring only (0.001<P<0.01). Furthermore, IL-6 showed a strong negative relationship with apo A-1 and HDL-cholesterol in females only (P<0.001). This study demonstrated that in a large healthy family population, children included, levels of IL-6 are closely associated with traditional and non-traditional atherosclerosis risk factors. All these data are useful for defining the precise role of cytokines in atherosclerosis mechanisms in physiological conditions.

Increased protein glycation in cerebrospinal fluid of Alzheimer's disease

Accumulation of advanced glycation end products occurs in the brain with ageing and was proposed to be involved in pathogenesis of Alzheimer's disease. We studied changes in the level of an early glycation product, an Amadori product, in cerebrospinal fluid (CSF) in ageing and in late-onset Alzheimer's disease. The work was carried out on 99 consecutive patients. The concentration of Amadori product in CSF correlated with CSF glucose concentration but was not changed with age (n = 70). In contrast, level of CSF Amadori product was 1.7-fold higher in Alzheimer's disease patients (n = 29) as compared with non-demented age-matched control group (n = 20; P < 0.0005), although CSF glucose concentration was similar in both groups (4.1 +/- 1.3 vs. 3.8 +/- 0.6 mmol/liter, resp.). An increased accumulation of Amadori products was found in all major proteins of CSF of Alzheimer's disease including albumin, apolipoprotein E and transthyretin. We propose that the increased early glycation of CSF proteins in the Alzheimer's patients may stimulate the formation and the consequent deposition of advanced glycation end products as well as oxidative stress in the brain.

gamma-Glutamyltransferase dependent generation of reactive oxygen species from a glutathione/transferrin system

In the presence of molecular oxygen and iron or copper ions, a number of antioxidants paradoxically generate reactive oxygen species (ROS) leading to free radical damage of nucleic acids and oxidative modification of lipids and proteins. The present work demonstrates that the combination of three components, which are often considered as part of an antioxidant protection system, can generate ROS. Purified human gamma-glutamyltransferase (GGT) in the presence of 2 mM glutathione (GSH) and 80 microM transferrin, as an iron source, at pH 7.4 generates ROS, as measured by chemiluminescence of luminol. Initiated by the addition of purified GGT, generation of ROS reached a maximal rate in the first 6 min. Intensity of the chemiluminescence was only slightly enhanced by addition of 200 microM hydrogen peroxide. Generation of ROS was also investigated in transfected V79 cells expressing human GGT. In comparison with GGT negative V79 cells, only recombinant cells expressing a high level of GGT on the cell membrane were able to generate ROS. Generation of ROS in these cells reached a maximum within 2 min and was enhanced by 200 microM hydrogen peroxide. We further confirmed the hypothesis that cysteinylglycine (CysGly), a product of GGT/GSH reaction, identified by high-performance liquid chromatography, but not GSH, was responsible for ROS formation initiated by the reductive release of iron from transferrin. These data clearly indicate that under physiological conditions, GGT is directly involved in ROS generation.

Localization of drug-metabolizing enzyme activities to blood-brain interfaces and circumventricular organs

The brain, with the exception of the choroid plexuses and circumventricular organs, is partially protected from the invasion of blood-borne chemicals by the specific morphological properties of the cerebral micro-vessels, namely, the tight junctions of the blood-brain barrier. Recently, several enzymes that are primarily involved in hepatic drug metabolism have been shown to exist in the brain, albeit at relatively low specific activities. In the present study, the hypothesis that these enzymes are located primarily at blood-brain interfaces, where they form an "enzymatic barrier," is tested. By using microdissection techniques or a gradient-centrifugation isolation procedure, the activities of seven drug-metabolizing enzymes in isolated microvessels, choroid plexuses, meningeal membranes, and tissue from three circumventricular organs (the neural lobe of the hypophysis, pineal gland, and median eminence) were assayed. With two exceptions, the activities of these enzymes were higher in the three circumventricular organs and cerebral microvessel than in the cortex. Very high membrane-bound epoxide hydrolase and UDP-glucuronosyltransferase activities (approaching those in liver) and somewhat high 7-benzoxyresorufin-O-dealkylase and NADPH-cytochrome P-450 reductase activities were determined in the choroid plexuses. The pia-arachnoid membranes, but not the dura matter, displayed drug-metabolizing enzyme activities, notably that of epoxide hydrolase. The drug-metabolizing enzymes located at these nonparenchymal sites may function to protect brain tissue from harmful compounds.

Determination of serum cystatin C: biological variation and reference values

Human cystatin C is a low molecular weight protein which has been proposed as a better marker of glomerular filtration rate than creatinine. To be able to interpret results obtained in different patient populations it is necessary to define cystatin C reference values. We measured serum concentration of cystatin C in 1223 subjects using a particle-enhanced nephelometric assay. Subjects were aged 4 to 79 years and were selected among apparently healthy individuals who came to the Centre for Preventive Medicine in Vandoeuvre-Lès-Nancy, France. We observed a Gaussian distribution of cystatin C concentration in serum. We did not find any effect of age or gender in children, hormonal status in women (puberty, menopause, oral contraceptives or hormone replacement therapy) or alcohol intake. Cystatin C concentration was slightly lower in female than in male adults below the age of 60 years. Cystatin C levels significantly increased above the age of 60 in both males and females, probably due to physiological aging of renal function. No other significant differences were observed between males and females. Using multiple regression analysis, moderate correlations were observed between body mass index and cystatin C, and between smoking and cystatin C, but these were not biologically significant. According to the literature, only methylprednisolone and cyclosporin A increased and decreased cystatin C levels, respectively. The reference values for cystatin C obtained in a carefully selected population were 0.75+/-0.089 mg/l for children aged 4-19 years, 0.74+/-0.100 mg/l for males and 0.65+/-0.085 mg/l for females (aged 20-59 years), and 0.83+/-0.103 mg/l for older individuals (> or =60 years).

Objectives, design and recruitment of a familial and longitudinal cohort for studying gene-environment interactions in the field of cardiovascular risk: the Stanislas cohort

The main objective of the Stanislas cohort is to study the role and the contribution of genetic and environmental factors to cardiovascular status. We plan: a) to describe the degree of association of a large number of cardiovascular risk indicators with cardiovascular endpoints, b) to evaluate the contribution of genetic and that of environmental factors to this association, c) to follow the evolution of these risk indicators during a period of at least ten years, d) to search for the determinants influencing this evolution. The principal variables studied are: a) blood pressure, cardiac mass, and wall thickness of carotid and femoral arteries, b) obesity and fat mass, c) indicators of lipid metabolism, d) genetic polymorphisms of several cardiovascular risk candidate genes, e) food, tobacco and alcohol consumption, f) consumption of drugs and anti-oxidant vitamins. Between September 1993 and August 1995, 1006 families consisting of the two biological parents with at least two children were recruited totalling 4295 individuals. This cohort will be followed up until 2004. There will be two health examinations five and ten years after the initial examination. A bank of blood samples (serum and plasma) in liquid nitrogen and DNA (-80 degrees C) has been established.

Apolipoprotein E serum concentration and polymorphism in six European countries: the ApoEurope Project

As part of the ApoEurope Project, the apolipoprotein E (apo E) serum concentration and polymorphism were determined in 6934 healthy subjects aged 25-64 years recruited in six European countries: Finland; France; Greece; Northern Ireland; Portugal and Spain. Age and sex influenced apo E concentration with concentrations being significantly higher in men than in women for those aged between 25 and 44 years. The age effect differed between the sexes after the age of 44 years, displaying a linear increase in women and a plateau in men. As expected, the serum apo E concentration was highest in varepsilon2 carriers and lowest in varepsilon4 carriers in each country with a significantly higher frequency of the varepsilon4 allele in the northern regions. The main finding of this study was a clear increasing North-South gradient in serum apo E concentration independent of age, sex and apo E genotype. In subjects aged <45 years and with the varepsilon3/varepsilon3 genotype, apo E concentration was higher in the South-East (Greece) as compared to the North by 20% for men and 32% for women. In addition to the genetic polymorphism, the geographical area is an important factor to take into account when studying serum apo E concentration in multicentre studies and defining reference values.

Subcellular distribution of cytochrome P-450 in the brain

The subcellular distribution of the monooxygenase complexes in the brain was studied by using subcellular fractionation and characterization of these fractions by marker enzymes. Cytochrome P-450 was found to be mainly localized in both synaptic and non-synaptic mitochondria; only a small quantity of enzyme was also found in the microsomal fraction. Peeling off the outer membrane of mitochondria showed that the protein was retained in the inner membrane fraction. A comparative study among some other species confirmed the mitochondrial prevalence of cerebral cytochrome P-450. A partial purification of the rat brain mitochondrial P-450 was obtained.

Pharmacogenomics Education: International Society of Pharmacogenomics Recommendations for Medical, Pharmaceutical, and Health Schools Deans of Education

Pharmacogenomics would be instrumental for the realization of personalized medicine in coming decades. Efforts are evident to clarify the potential bioethical, societal, and legal implications of key pharmacogenomics-based technologies projected to be soon introduced into the core practice of medicine. In sharp contrast, a lack of sufficient attention to educational aspects of pharmacogenomics, both for professionals and for society at large, is evident. In order to contribute to this discussion, a 'Pharmacogenomics Education Forum' was held on October 2, 2004 during the 3rd Annual Meeting of the International Society of Pharmacogenomics (ISP) at Santorini, Greece. The participants, members of the ISP Pharmacogenomics Education Forum, after deliberate discussions, proposed a document of 'Background Statement' and 'Recommendations and Call for Action' addressed to Deans of Education at Medical, Pharmaceutical, and Health Schools globally. This document has been considered by the education committee of the International Society of Pharmacogenomics and the result is presented here. We hope that this call would be listened to, and soon followed by beneficial action, ultimately leading to enhanced implementation of personalized medicine into core medical education and practice.

Subcellular localization of cytochrome P450, and activities of several enzymes responsible for drug metabolism in the human brain

We studied the subcellular distribution of cytochrome P450 and related monooxygenase activities in six regions of human brains removed at autopsy. The content of total cytochrome P450 was found to be at least nine times higher in the mitochondrial fraction than in the microsomes in all the regions studied. However, cytochrome P450-dependent enzymatic activities which are representative of different isoforms metabolizing exogenous molecules exhibited a microsomal prevalence, a situation previously observed in rat brain. The other drug-metabolizing enzymes catalysing functionalization and conjugation reactions, presented the following characteristics in human brain: (i) a low activity of NADPH-cytochrome P450 reductase, which also catalyses the reduction of some xenobiotics; (ii) a high specific activity of the membrane-bound epoxide hydrolase; (iii) among the enzymes catalysing conjugation reactions, 1-naphthol-UDP-glucuronosyltransferase activity was barely or not detectable, whereas the mean glutathione-S-transferase activity was 15 times higher than the activity measured in rat brain. The presence of several drug-metabolizing enzyme activities in human brain microvessels, and particularly the high activity of epoxide hydrolase, suggests a participation of these enzymes in the metabolic blood-brain barrier.