The SIESTA method; developments and applicability

Recent developments in and around the SIESTA method of first-principles simulation of condensed matter are described and reviewed, with emphasis on (i) the applicability of the method for large and varied systems, (ii) efficient basis sets for the standards of accuracy of density-functional methods, (iii) new implementations, and (iv) extensions beyond ground-state calculations.

Accelerated modern human-induced species losses: Entering the sixth mass extinction

The oft-repeated claim that Earth's biota is entering a sixth "mass extinction" depends on clearly demonstrating that current extinction rates are far above the "background" rates prevailing between the five previous mass extinctions. Earlier estimates of extinction rates have been criticized for using assumptions that might overestimate the severity of the extinction crisis. We assess, using extremely conservative assumptions, whether human activities are causing a mass extinction. First, we use a recent estimate of a background rate of 2 mammal extinctions per 10,000 species per 100 years (that is, 2 E/MSY), which is twice as high as widely used previous estimates. We then compare this rate with the current rate of mammal and vertebrate extinctions. The latter is conservatively low because listing a species as extinct requires meeting stringent criteria. Even under our assumptions, which would tend to minimize evidence of an incipient mass extinction, the average rate of vertebrate species loss over the last century is up to 100 times higher than the background rate. Under the 2 E/MSY background rate, the number of species that have gone extinct in the last century would have taken, depending on the vertebrate taxon, between 800 and 10,000 years to disappear. These estimates reveal an exceptionally rapid loss of biodiversity over the last few centuries, indicating that a sixth mass extinction is already under way. Averting a dramatic decay of biodiversity and the subsequent loss of ecosystem services is still possible through intensified conservation efforts, but that window of opportunity is rapidly closing.

The SIESTA method; developments and applicability

Recent developments in and around the SIESTA method of first-principles simulation of condensed matter are described and reviewed, with emphasis on (i) the applicability of the method for large and varied systems, (ii) efficient basis sets for the standards of accuracy of density-functional methods, (iii) new implementations, and (iv) extensions beyond ground-state calculations.

Phenolic compounds in Spanish olive oils

Phenolic compounds in Spanish virgin olive oils were characterized by HPLC. Simple phenols such as hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, ferulic acid, and vanillin were found in most of the oils. The flavonoids apigenin and luteolin were also found in most of the oils. The dialdehydic form of elenolic acid linked to tyrosol and hydroxytyrosol was also detected, as were oleuropein and ligstroside aglycons. The structure of a new compound was elucidated by MS and NMR as being that of 4-(acetoxyethyl)-1,2-dihydroxybenzene. Changes of phenolic compounds in virgin olive oils with maturation of fruits were also studied. Hydroxytyrosol, tyrosol, and luteolin increased their concentration in oils with maturation of fruits. On the contrary, glucoside aglycons diminished their concentration with maturation. No clear tendency was observed for the rest of the phenolic compounds identified.

Recovery of the hypothalamic-pituitary-adrenal response to stress. Effect of stress intensity, stress duration and previous stress exposure

Pathological consequences of stress-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis may be related to the duration rather than to the intensity of HPA axis activation after exposure to the stressor. Consequently a fine analysis of post-stress events is of importance. The present experiments were designed to study the importance of three key factors in HPA recovery: intensity of the stressor (experiment 1), duration of exposure to the stressor (experiment 2) and previous experience of the animals with the situation (experiments 3 and 4). In experiment 1, analysis of both the response to the stressor and the poststress period showed that the stronger the stressor, the greater the area under the curve of HPA activation. In experiment 2, different groups of rats were exposed to different periods of immobilization (IMO) (20 min, 1 h and 2 h) and sampled before, during and after exposure to IMO. The speed of recovery of plasma corticotropin (ACTH) levels was not related to the duration of exposure to the stressor. In experiments 3 and 4, the influence of previous experience with the stressor was studied in rats daily exposed to 20 min IMO or daily injected with hypertonic saline (HS) for 8 days and sampled on days 1, 2, 5 and 8. Whereas a significant decline in plasma ACTH levels was not observed immediately after IMO until day 8, a single previous exposure to IMO was enough to enhance recovery 90 min after the end of exposure to IMO. Corticosterone levels were related to the number of previous experiences with the stressor only in the post-IMO period. In response to a novel stressor (forced swimming), chronic IMO rats showed a slightly impaired recovery as compared to stress-naive rats, suggesting that enhanced recovery of the HPA axis was specific for the homotypic stressor. After daily HS injections, a pattern similar to that after IMO was observed, the delayed, but not the early response of the HPA axis being reduced as a function of the number of previous experiences with the situation. Taken together, the present results suggest that the speed of recovery of the HPA axis after its activation by stressors is sensitive to the intensity of the stressors but not to their duration, and that adaptation to a repeated stressor is more apparent during the delayed HPA response.

Psychological characteristics of morbidly obese candidates for bariatric surgery

BACKGROUND

Morbid obesity has multiple negative consequences for psychological health. These patients are described as depressed, anxious, and impulsive, with low self-esteem and impaired quality of life. The severity of these psychological disorders has been related to the degree of obesity. The aim of this study was to analyze the psychopathological characteristics of obese candidates for bariatric surgery, determining differences and similarities in general and specific psychopathologic symptoms among patients with different degrees of obesity and normal-weight individuals.

METHODS

The study included 50 patients (26 type III obesity, 24 type IV obesity) and 25 normal-weight volunteers. They were all assessed for: stress (CED44-B), anxiety-depression (General Health Questionnaire), self-esteem (Rosenberg Self-Esteem Scale), family function (Apgar Family Function Questionnaire), quality of life (Spanish version of the Quality of Life Index), personality (Eysenck Personality Questionnaire-Revised), food craving (Food Craving Questionnaire-Trait), and eating behavior disorder (EBD) symptomatology (Eating Disorders Examination-Questionnaire Version-4).

RESULTS

The obese patients had higher levels of stress, anxiety, depression, food craving, and EBD symptoms and lower levels of self-esteem and quality of life compared with normal-weight controls. No personality or family function disorders were observed in any of the obese or normal-weight subjects. Patients with type III and type IV obesity differed only in anxiety and personality findings.

CONCLUSIONS

Although the presence of psychological disorders cannot be taken as an absolute criterion for exclusion of candidates for obesity surgery, a better understanding of the relationship of these variables with weight loss and other outcomes of bariatric surgery may improve patient selection and facilitate more appropriate interventions.

Surfactant protein genetic marker alleles identify a subgroup of tuberculosis in a Mexican population

Pulmonary surfactant and its components are essential for normal lung function and are involved in local host defense. Surfactant protein (SP)-A and SP-D bind to and modulate phagocytosis of Mycobacterium tuberculosis by macrophages. Frequency comparisons of SP marker alleles in tuberculosis patients and healthy control subjects (tuberculin-skin test positive or general population) were performed. Regression analyses of the tuberculosis and the tuberculin-skin test positive groups revealed, on the basis of odds ratios, tuberculosis susceptibility (DA11_C and GATA_3) and protective (AAGG_2) marker alleles. Similarly, between tuberculosis patients and general population control subjects, susceptibility 1A(3), 6A(4), and B1013_A and protective AAGG_1, and AAGG_7 marker alleles were observed. Moreover, interactions were seen between alleles 6A(2) and 1A(3) (P=.0064) and between 1A(3) and B1013_A (P=. 036). The findings indicate a possible involvement of SP alleles in tuberculosis pathogenesis.

Protein phosphatase 1alpha is a Ras-activated Bad phosphatase that regulates interleukin-2 deprivation-induced apoptosis

Growth factor deprivation is a physiological mechanism to regulate cell death. We utilize an interleukin-2 (IL-2)-dependent murine T-cell line to identify proteins that interact with Bad upon IL-2 stimulation or deprivation. Using the yeast two-hybrid system, glutathione S-transferase (GST) fusion proteins and co-immunoprecipitation techniques, we found that Bad interacts with protein phosphatase 1alpha (PP1alpha). Serine phosphorylation of Bad is induced by IL-2 and its dephosphorylation correlates with appearance of apoptosis. IL-2 deprivation induces Bad dephosphorylation, suggesting the involvement of a serine phosphatase. A serine/threonine phosphatase activity, sensitive to the phosphatase inhibitor okadaic acid, was detected in Bad immunoprecipitates from IL-2-stimulated cells, increasing after IL-2 deprivation. This enzymatic activity also dephosphorylates in vivo (32)P-labeled Bad. Treatment of cells with okadaic acid blocks Bad dephosphorylation and prevents cell death. Finally, Ras activation controls the catalytic activity of PP1alpha. These results strongly suggest that Bad is an in vitro and in vivo substrate for PP1alpha phosphatase and that IL-2 deprivation-induced apoptosis may operate by regulating Bad phosphorylation through PP1alpha phosphatase, whose enzymatic activity is regulated by Ras.

Charcot-Marie-Tooth disease type 1A with 17p duplication in infancy and early childhood: a longitudinal clinical and electrophysiologic study

OBJECTIVE

We describe longitudinal clinical and electrophysiologic evaluation of Charcot-Marie-Tooth disease type 1A (CMT-1A) in infancy and early childhood.

BACKGROUND

The clinical picture and electrophysiologic evaluation of CMT-1A during the age of nerve conduction maturation have not been documented.

DESIGN/METHODS

Twenty at-risk children from six unrelated CMT-1A families were examined in the first 5 years of life. Initial ages were 1 month to 4 years (mean, 1.5 years) and final ages 4 to 19 years (mean, 9 years). All subjects had two or more motor and sensory conduction velocities (MCV and SCV), corrected distal motor latencies (DML), and F-waves.

RESULTS

Twelve children were affected. Initially, two of these (17%) had symptoms, whereas five (42%) were symptomatic at the end. Numbers of abnormal examinations at the beginning was six (50%) and at conclusion was 10 (83%). None of the patients were disabled. From 2 years of age, all affected children had abnormal MCV, SVC, F-waves, and DML. Prolonged DML was already present in the first months of life and preceded slowing of MCV in three cases.

CONCLUSION

The electrophysiologic studies were concordant with the presence or absence of the CMT-1A DNA duplication. In most CMT-1A patients, symptoms appear in early childhood, although the florid clinical picture does not occur until the second decade of life. Serial electrophysiologic studies can detect the CMT-1A gene carrier in infancy.

Impact of highly active antiretroviral therapy on blood pressure in HIV-infected patients. A prospective study in a cohort of naive patients

OBJECTIVES

To assess the impact of highly active antiretroviral therapy (HAART) on the blood pressure (BP) of naive patients after 1 year of treatment.

METHODS

A prospective, observational study of 95 HIV-positive patients in our Unit starting HAART between January 2001 and October 2002 and maintaining the same regimen for 48 weeks of follow-up was carried out. Data on blood pressure (BP) and demographic, epidemiological, clinical, immunovirological and therapeutic characteristics related to HIV infection were collected prior to HAART and at week 48. High blood pressure (HBP) [systolic BP (SBP) > or =140 mm Hg and/or diastolic BP (DBP) > or =90 mm Hg] was defined according to international criteria.

RESULTS

Of the 95 patients, 78 were men, 44% had AIDS and 68% were smokers, and their mean age was 40 years. At week 48 the prevalence of HBP was 26% and SBP, DBP and pulse pressure (PP) increased (121.8 versus 116.6 mm Hg, P=0.0001; 76.3 versus 69.7 mm Hg, P=0.004; 46.9 versus 43.8 mm Hg, P=0.001, respectively). Univariate analysis showed that HBP was associated with older age, higher body mass index (BMI), higher baseline lipids, and higher baseline BP. A linear regression model adjusting for age and sex suggested a significant impact of older age, higher baseline SBP, higher baseline hypercholesterolaemia and lower baseline CD4-cell count on SBP increase.

CONCLUSIONS

Blood pressure increased after 48 weeks of HAART, leading to an important prevalence of hypertension. The increase in SBP depended on age and baseline lipid profile and immunological status. BP should be periodically measured and treated when necessary in HIV-infected patients on HAART.

Acid hydrolysis of secoiridoid aglycons during storage of virgin olive oil

The main change found in the phenolic composition of virgin olive oils of Arbequina, Hojiblanca, and Picual varieties during storage in darkness at 30 degrees C was the hydrolysis of the secoiridoid aglycons. This reaction gave rise to an increase in the free phenolics hydroxytyrosol and tyrosol in the oil. Filtration of oil and acidity influenced the hydrolysis to a large extent. Thus, the addition of commercial oleic acid to Hojiblanca and Picual oils increased the hydrolysis rate of the secoiridoid aglycons. In contrast, the concentration of lignans 1-acetoxypinoresinol and pinoresinol remained constant during storage. It must also be stressed that the total molar concentration of the phenolic compounds analyzed in the oils changed slightly (<20% reduction) after one year of storage, which is important from a nutritional point of view. However, the transformation of the secoiridoid aglycons into free phenolics may have consequences on oil taste and antioxidant capacity.

Competence of health professionals to check the carotid pulse

Our objective was to establish the proportion of Emergency Room and Intensive Care doctors and nurses able to locate the carotid pulse in less than 5 s, and identify the variables that influence this ability. The method followed was locating the carotid pulse in a healthy male adult volunteer with normal blood pressure in two situations (stretcher or floor) and with the neck in either a neutral or in an extended position. We recorded the gender, age, and previous training in cardiopulmonary resuscitation (CPR) of each participant and the time spent in detecting the pulse in each of the four possible positions. A model of logistic regression was constructed to determine if the patient's position had any influence on the proportion of health workers capable of finding the pulse within 5 s. The average age of the 72 subjects studied was 33.4 years (SD = 6.6); 80% of the participants had CPR training. Thirty-one participants (43.1%; CI 95%, 31.4-55.3%) required more than 5 s to detect the pulse, although only three (4.2%; CI 95%, 0.9-11.7%) required more than 10 s. The variable 'no CPR training' was associated with the inability to detect the pulse within 5 s. The detection of the pulse was easier with an extended neck. A significant proportion of nurses and doctors were slow to locate the carotid pulse on a healthy, young volunteer with normal blood pressure. No relation was found between gender or age of the participants. More attention should be given to carotid pulse detection in CPR training.

Nutrient adequacy and Mediterranean Diet in Spanish school children and adolescents

OBJECTIVE

To evaluate dietary habits and nutritional status of Spanish school children and adolescents, and their relationship with the Mediterranean Diet.

DESIGN

Cross-sectional study by face-to-face interview.

SETTING

Free living children and adolescents of all Spanish regions.

SUBJECTS

A random sample of 3166 people aged 6-24 y.

METHODS

Home interviews conducted by a team of 43 dietitians included 24-h recalls (a second 24-h recall in 25% of the sample) and a short frequency questionnaire to determine the quality of the Mediterranean Diet (KIDMED).

RESULTS

The participation rate was 68%. In general, the adequacy of the Mediterranean Diet rose with increased mean intakes of the majority of vitamins and minerals and decreased percentages of inadequate intakes (&<2/3 of the RNI) for calcium, magnesium, vitamin B(6) and C in both sexes, and iron and vitamin A only in females.

CONCLUSIONS

This study demonstrates that the Mediterranean Diet contributes to nutritional quality, and also shows concomitant risks as the Mediterranean Diet deteriorates.

Telemedicine as a tool for intensive management of diabetes: the DIABTel experience

This paper presents the current features of the DIABTel telemedicine system and the evaluation outcomes of its use in clinical routine. This telemedicine system is designed to complement the daily care and intensive management of diabetic patients through telemonitoring and telecare services. The system comprises a patient unit (PU) used by patients in their day-to-day activities and a Medical Workstation used by physicians and nurses at hospitals. Both applications offer tools to collect, manage, view and interpret data and to exchange data and messages. The system was evaluated for usability, telemedical protocols, metabolic control and quality of life. This evaluation consisted in a 6-month cross-over pilot study with ten Type I diabetic patients. The results of the evaluation allowed assessment of the telemedicine protocols in terms of the number of communications/patient (21.6+/-7.7); days between communications (5.4+/-2.66); messages sent by physicians (118 text messages); and data and messages transmitted by patients (3524 blood glucose readings, 1649 day-to-day insulin adjustments, 24 exercise reports, ten diet modifications and 63 text messages). Physicians performed more therapeutic changes during the DIABTel period than in the control period. There was a trend towards HbA1c improvement during DIABTel use with no incidence in the number of hypoglycaemias. This pilot study demonstrates the feasibility of the DIABTel system in clinical routine use and its potential benefits for diabetes care: improving the availability of information necessary for therapy adjustments; offering new physician-patient communication tools; increasing patient empowerment and education; and showing a positive trend towards improving the metabolic control of patients. Further studies are needed to validate these findings and to promote telemedicine as an opportunity to better diabetes care.

General binocular disorders: prevalence in a clinic population

The purpose of this paper was to study the prevalence of nonstrabismic accommodative and binocular dysfunctions in a clinical population. We examined 265 symptomatic patients who were chosen from an optometric clinic. We performed several tests to diagnose any form of refractive, accommodative or binocular dysfunction. Of the 265 subjects examined, 59 patients (22.3%) had some form of accommodative or binocular dysfunction and required not just the correction of the refractive error but a specific treatment for each of the problems diagnosed. The remaining subjects were classed as having refractive anomalies. The frequency of binocular dysfunctions was 12.9%, and 9.4% for accommodative anomalies. Convergence excess (4.5%) was more prevalent than convergence insufficiency (0.8%) and accommodative excess (6.4%) more prevalent than accommodative insufficiency (3%).

Chromosome loss is the most frequent mechanism contributing to HLA haplotype loss in human tumors

Loss of heterozygosity (LOH) in the short arm of chromosome 6 (6p) was detected in samples obtained from colon (13.8%), larynx (17.6%) and melanoma (15.3%) tumors. The parallel study of HLA-antigen expression in tumor tissues using locus- and polymorphic-specific antibodies in combination with LOH microsatellite analysis on 6p allowed us to establish that LOH in chromosome 6 is a representative phenomenon in most tumor cells present in a given tumor tissue. In most cases, specific HLA alleles had been lost in a predominant population of tumor cells, indicating that LOH is a non-irrelevant mutation that probably confers a selective advantage for survival of the mutant cell. We also demonstrate that LOH frequently occurred through chromosome loss rather than somatic recombination. LOH at all loci studied on the p and q arms of chromosome 6 was observed in at least 56.2% (9/17) cases. This HLA-associated microsatellite analysis was a useful tool for classifying tumors as LOH-positive or -negative, and therefore to consider a patient as a potential non-responder or responder in a vaccination trial.

Single exposure to stressors causes long-lasting, stress-dependent reduction of food intake in rats

A single exposure to severe stressors has been shown to cause anorexia in the next 24 h, but the duration of such alterations is not known. Male Sprague-Dawley rats were subjected to different stressors, and food intake was measured for several days after stress. In experiment 1, 2 h of immobilization (Imo) and lipopolysaccharide (LPS) administration (1,000 microgram/kg) caused a marked anorexia in the 24 h after stress, which persisted on poststress day 3. In experiment 2, changes in food intake after LPS and Imo were followed until total recovery. As in experiment 1, LPS caused initially a greater degree of anorexia than Imo, but normal food intake recovered much faster (poststress day 3 vs. poststress day 9). Changing the period of exposure to Imo between 20 min and 6 h (experiment 3) only slightly modified the pattern of response to the stressor. When different doses of LPS (50, 250, and 1,000 microgram/kg) were tested in experiment 4, a dose-dependent effect on food intake was observed, the greatest doses causing the most marked and lasting effect. The present results showed stressor-specific lasting changes in food intake caused by a single exposure to some stressors, the effect of a severe psychological stressor such as Imo being more lasting than that of LPS, despite a lower initial anorexia. A severe psychological stressor and a physical stressor such as LPS appear to change food intake in different ways.

Phosphorylation of the alpha subunit of initiation factor 2 correlates with the inhibition of translation following transient cerebral ischaemia in the rat

Rats were subjected to the standard four-vessel occlusion model of cerebral transient ischaemia (vertebral and carotid arteries) for 15 and 30 min. After a 30 min recirculation period, protein synthesis rate, initiation factor 2 (eIF-2) and guanine nucleotide exchange factor (GEF) activities, and the level of phosphorylation of the alpha subunit of eIF-2 (eIF-2 alpha) were determined in the neocortex region of the brain from sham-operated controls and ischaemic animals. Following reversible cerebral ischaemia, the protein synthesis rate, as measured in a cell-free system, was significantly inhibited (70%) in the ischaemic animals. eIF-2 activity, as measured by its ability to form a ternary complex, also decrease parallel to the decrease in protein synthesis. As eIF-2 activity was assayed in the presence of Mg2+ and GTP-regenerating capacity, the decrease in ternary-complex formation indicated the possible impairment of GEF activity. Since phosphorylated eIF-2 [eIF-2(alpha P)] is a powerful inhibitor of GEF, the levels of phosphorylated eIF-2 alpha were determined, and an increase from 7% phosphorylation in sham control rats to 20% phosphorylation in 15 min and 29% phosphorylation in 30 min in ischaemic rats was observed, providing evidence for a tight correlation of phosphorylation of eIF-2 alpha and inhibition of protein synthesis. Moreover, GEF activity measured in the GDP-exchange assay was in fact inhibited in the ischaemic animals, proving that protein synthesis is impaired by the presence of eIF-2(alpha P), which blocks eIF-2 recycling.

Validation of a HPLC quantification of acetaminophen, phenylephrine and chlorpheniramine in pharmaceutical formulations: capsules and sachets

Acetaminophen, phenylephrine and chlorpheniramine are frequently associated in pharmaceutical formulations against the common cold. Their quantification presents several problems. A HPLC method for the simultaneous determination of these compounds in pharmaceutical formulations such as capsules and sachets, including the separation of impurities and excipients has been developed and validated. The selectivity of the method was also tested to be used if phenylpropanolamine hydrochloride were employed instead of phenylephrine. Final chromatographic conditions were a gradient elution, being solvent A: phosphate buffer 40 mM at pH 6.0 and solvent B: acetonitrile. At t=0, the mobile phase consisted of 92% A and 8% B and it changed with a linear gradient during 8 min to 75% A and 25% B. At min 8, it changed to 30% A and 70% B for 5 min and at t=15 min, it returns to the initial conditions (92% A and 8% B) during 1 min remaining at this composition until t=20 min. UV detection was performed at 215 nm for phenylephrine and chlorpheniramine, because at this wavelength sensitivity was higher than in other more characteristic wavelengths and it was necessary for the detection of minor compounds. For acetaminophen 280 nm was employed. Validation parameters permit to consider the method adequate.

Partial Removal of Lipopolysaccharide from Thiobacillus ferrooxidans Affects Its Adhesion to Solids

Conditions for the partial removal of lipopolysaccharide (LPS) from Thiobacillus ferrooxidans are described. Raising the pH of the solution containing the cells from pH 1.5 to pH 6.8 to 8.0 releases about 50% of the LPS without cell lysis. The release of LPS begins at pH 3.5, and it was not affected by EDTA concentration. Partial removal of LPS exposed higher amounts of a 40-kDa outer membrane protein in the bacteria, as detected by a dot immunoassay employing an antiserum against the T. ferrooxidans surface protein. This higher protein exposure and the reduced LPS content increased the hydrophobicity of the cell surface, as determined by an increased adhesion (50%) to hydrophobic sulfur prills and C-dodecanoic acid binding (2.5-fold) compared with control cells. In addition, adhesion of radioactively labeled microorganisms to a sulfide mineral was inhibited (40%) in the presence of previously added LPS. Our results suggest that not only LPS but also surface proteins probably play important roles in T. ferrooxidans adhesion to solid surfaces.

Rapid and complete extraction of phenols from olive oil and determination by means of a coulometric electrode array system

Extraction methods to determine olive oil phenols are not exhaustive. A procedure to test their effectiveness, based on the treatment of the extracted oil with 2 N HCl followed by analysis of phenols in the aqueous phase, has been developed. It was concluded, using this test, that 15-40% of phenols remained unextracted when the liquid/liquid extraction method with 80% methanol was applied. Solid phase extraction (C(18) cartridge) succeeded in retaining most of the phenols in the cartridge, but the recovery yield from the sorbent material was low. However, a new extraction method, based on the use of N,N-dimethylformamide (DMF) as an extraction solvent, achieved a complete extraction of phenols from oils. The proposed method requires a lower amount of oil, solvents, energy, and labor than the traditional ones. Because of the low concentration of phenols in the DMF extract, the highly sensitive electrochemical detector (EC) technique was studied. All of the phenols detected by the traditional UV detectors were also detected by EC using a coulometric array system. A rapid and complete analytical methodology of phenols in olive oil has been proposed based on coupling DMF extraction and EC detection.

Development and validation of a capillary electrophoresis method for direct measurement of isocitric, citric, tartaric and malic acids as adulteration markers in orange juice

Fruit juices each have very distinct organic acids profiles that can be used as fingerprints for establishing authenticity. A method has been developed, optimised and validated for measuring by capillary electrophoresis citric, isocitric, malic and tartaric acids as authenticity markers in orange juices, without any sample treatment other than dilution and filtration. Final conditions were phosphate buffer 200 mM, pH 7.50, -14 kV as applied potential, and 57 cm length neutral capillary. Detection was direct UV at 200 nm. Different kinds and marks of orange juice, chosen from the great variety existent in the market, were analysed and clear differences could be found between them and just pressed orange juice.