Fasting plasma carotenoids concentrations in Crohn's and pancreatic cancer patients compared to control subjects.

Carotenoids are colored molecules that are widespread in the plant kingdom, but animals cannot synthesize them. Carotenes are long, apolar molecules which require fully functioning digestive processes to be absorbed properly. Hence they could be interesting markers of intestinal absorption and digestion. Indeed, only few tests are available to assess these processes and only the D-xylose tolerance test is routinely used. However D-xylose is a sugar that tests only the absorption of water-soluble compounds and it only tests duodenal absorption. In this study, we have evaluated carotenoids as markers of digestion and absorption. We compared fasting plasma carotenoids concentrations in 21 control subjects, 20 patients with Crohn's disease, and 18 patients with pancreatic cancer. Crohn's disease alters intestinal absorption while pancreatic cancer decreases pancreatic enzyme secretion thus impairing digestion. Results show that all carotenoids are significantly lower in Crohn's and cancer patients as compared to control subjects and the multifactorial analysis shows that this decrease is mostly independent of dietary intake. Interestingly, maldigestion as seen in pancreatic cancer more strongly influences plasma lutein and lycopene concentrations while malabsorption in Crohn's disease acts on other carotenoids. Thus carotenoids could be interesting alternatives for testing and following patients that are suspected of having malabsorption or maldigestion syndromes.

Serum carotenoids, vitamins A and E, and 8 year lung function decline in a general population.

BACKGROUND: Oxidative stress is thought to have a major role in the pathogenesis of airway obstruction. A study was undertaken to determine whether subjects with low levels of antioxidants (serum beta-carotene, alpha-carotene, vitamins A and E) would be at a higher risk of accelerated decline in forced expiratory volume in 1 second (FEV1) as their lungs would be less protected against oxidative stress. METHODS: 1194 French subjects aged 20-44 years were examined in 1992 as part of the European Community Respiratory Health Survey (ECRHS); 864 were followed up in 2000 and 535 (50% men, 40% lifelong non-smokers) had complete data for analysis. RESULTS: During the 8 year study period the mean annual decrease in FEV1 (adjusted for sex, centre, baseline FEV1, age, smoking, body mass index and low density lipoprotein cholesterol) was 29.8 ml/year. The rate of decrease was lower for the subjects in tertile I of beta-carotene at baseline than for those in the two other tertiles (-36.5 v -27.6 ml/year; p = 0.004). An increase in beta-carotene between the two surveys was associated with a slower decline in FEV1. No association was observed between alpha-carotene, vitamin A, or vitamin E and FEV(1) decline. However, being a heavy smoker (> or =20 cigarettes/day) in combination with a low level of beta-carotene or vitamin E was associated with the steepest decline in FEV1 (-52.5 ml/year, p = 0.0002 and -50.1 ml/year, p = 0.010, respectively). CONCLUSIONS: These results strongly suggest that beta-carotene protects against the decline in FEV1 over an 8 year period in the general population, and that beta-carotene and vitamin E are protective in heavy smokers.

[Measurement of urinary free cotinine. Comparison with the level of expired air carbon monoxide]. / Dosage de la cotinine urinaire libre. Deuxième partie: comparaison avec le taux de monoxyde de carbone dans l'air expiré.

BACKGROUND AND AIM: Cotinine is a very reliable index for the estimation of active or passive smoking. Sampling from a single urine void is well accepted by smokers who are willing to stop. It is not possible to exclude modification of urine cotinine according to beverage intake. The aim of this study was to determine if urine cotinine concentration must necessarily be adjusted to creatinine or not, by making comparison with expired air carbon monoxide. MATERIAL AND METHODS: Carbon monoxide was measured in 53 smokers coming for the first time in a smoking cessation program. Urine cotinine was measured by HPLC-UV. The cut-off value for abstinence is 8ppm and 0.05 mg/L, repectively. Urine creatinine was determined using the Jaffe reaction. RESULTS: Mean CO level was 18.5 +/- 10.6 ppm and mean urine cotine was 1.45 +/- 0.86 mg/L. Eight smokers had CO 8 ppm. They should be considered as abstinent. However, only one of them had a cotinine under the detection limit. Urine creatinine varied in a large range (0.7 - 35 mmol/L). But, cotinine was only weakly correlated to creatinine (r = 0.279, p = 0.037). There was a highly significant correlation between cotinine and CO (0.649, p = 0.0001). The correlation of cotinine/creatinine versus CO was not significant (r = 0.249, p = 0.072). In order to take into account fluid intake, urine cotinine of each sample was adjusted as if creatinine was equal to the mean (8.3 mmol/L) of the group of subjects. The correlation observed with adjusted or non adjusted cotinine and CO (r = 0.640, p < 0.0001) was the same. CONCLUSION: Urine cotinine from a single void is an accurate index of tobacco smoking at the individual level. There is no need to adjust cotinine concentration, taking into account urine creatinine. Measurement of urine cotinine can be useful to manage smokers who deliberately wish to overcome tobacco dependence, offering the opportunity to provide an adequate level of nicotine substitutive therapy. It is also of peculiar importance to follow-up pregnant women and smokers for whom cessation is required after a clinical event. Finally, absence of cotinine in urine can be used to document abstinence from tobacco products.

[Urinary cotinine and nicotine metabolites measurement]. / Dosage urinaire de la cotinine et des métabolites de la nicotine.

UNLABELLED: According to the recent regulations (Circulaire DGS/DH du 3 avril 2000), tobacco dependence must be determined by the measurement of urine nicotine metabolites. Various assay methods are presently available. They were tested in order to evaluate their analytical performances and to determine how they can be used for the clinical management of smoking cessation. MATERIAL AND METHODS: Urine samples from a single void (n = 97) were obtained from active and abstinent smokers (with or without nicotine substitutive therapy). They were all analyzed by the various methods. Cotinine concentration was measured in six laboratories, using HPLC combined with UV detection according to a standardized procedure (Ann Biol Clin 2002 : 60 : 263-72). Immunoassay methods were also tested and the values obtained from urine samples were compared to urine cotinine measured by HPLC-UV. RESULTS: HPLC-UV: Urinary cotinine varied in a range from undetectable to 4 mg/L. An interlaboratory comparison was performed according to the Valtec procedure (calculation of equation of Deming, chart of differences). There was a good accordance between laboratories. Cotinine concentration was only slightly influenced by fluid intake, as shown by a poorly significant correlation between cotinine and creatinine (r = 0.23, p = 0.05). Homogeneous immunoassays: The two homogeneous immunoassays (Cotinine) from Thermo Electron and Cotinine Enzyme Immunoassay commercialized by Microgenics were highly correlated (r = 0.97). The correlation was not so strong with HPLC-UV (r = 0.86). Firstly, values were found higher with immunoassays because antibodies crossreact with 3-hydroxycotinine. Secondly, the ratio of immunoassays values to HPLC-UV values varied according to urine specimens. Finally, there was a highly significant correlation with urine creatinine (r = 0.40, p = 0.0001), thus indicating the influence of fluid intake. Heterogeneous immunoassay: The kit Metabolites of Nicotine commercialized by DPC France was tested on the analyzer Immulite, using a procedure specifically established for urine. Antibodies revealed a large spectrum of nicotine metabolites. Therefore, the values were much higher than those observed for the same urine samples with homogeneous immunoassays. CONCLUSION: HPLC-UV can be recommended for the measurement of urinary cotinine, as it was shown a good accordance between laboratories. The low detection limit is of interest for the diagnosis of Environmental Tobacco Smoking. Homogeneous immunoassays can be easily used for routine analysis as they can be performed directly on urine specimen. The results must be interpreted according to cut-off values specifically established according to homogeneous or heterogeneous immunoassays. Variability induced by fluid intake must be taken into account. The interest of the heterogeneous immunoassay needs to be confirmed for the diagnosis of Environmental Tobacco Smoking.

[Recent knowledge about intestinal absorption and cleavage of carotenoids]. / Données récentes sur l'absorption et le catabolisme des caroténoïdes.

Our knowledge about intestinal absorption and cleavage of carotenoids has rapidly grown during the last years. New facts about carotenoid absorption have emerged while some controversies about cleavage are close to end. The knowledge of the absorption and conversion processes is indispensable to understand and interpret the perturbations that can occur in the metabolism of carotenoids and vitamin A. Recently, it has been shown that the absorption of certain carotenoids is not passive - as believed for a long time - but is a facilitated process that requires, at least for lutein, the class B-type 1 scavenger receptor (SR-B1). Various epidemiological and clinical studies have shown wide variations in carotenoid absorption from one subject to another, such differences are now explained by the structure of the concerned carotenoid, by the nature of the food that is absorbed with the carotenoid, by diverse exogenous factors like the intake of medicines or interfering components, by diet factors, by genetic factors, and by the nutritional status of the subject. Recently, the precise mechanism of beta-carotene cleavage by betabeta-carotene 15,15' monooxygenase (EC 1.14.99.36) - formerly called beta-carotene 15,15' dioxygenase (ex EC 1.13.11.21) - has been discovered, and a second enzyme which cleaves asymmetrically the beta-carotene molecule has been found. beta-carotene 15,15' monooxygenase only acts on the 15,15' bond, thus forming two molecules of retinal from one molecule of beta-carotene by central cleavage. Even though the betabeta-carotene 15,15' monooxygenase is much more active on the beta-carotene molecule, a study has shown that it can act on all carotenoids. Searchers now agree that other enzymes that can catalyse an eccentric cleavage of carotenoids probably exist, but under physiological conditions the betabeta-carotene 15,15' monooxygenase is by far the most active, and it is mainly effective in the small bowel mucosa and in the liver. However the conversion of provitamin A carotenoids into vitamin A is only partial, and requires a satisfactory protein status.

[Recommendations for the installation in the laboratory of metrological functions and corresponding documentation (Document B)]. / Recommandations pour l'installation dans le laboratoire de la fonction métrologie et de la documentation correspondante (Document B).

In order to ensure the quality of analytical results, clinical laboratories shall have a perfect control of process and equipments of measurement. Therefore is recommended individualisation of metrological function, generally entrusted the quality manager. This quality manager will draw up a metrological traceability, verifications and confirmations, control of non conformities, follow-up and evaluation of metrological function.

[Presentation for the use of a clinical laboratories of standards of metrology (Document A)]. / Présentation, à l'usage des laboratoires d'analyses de biologie médicale, des normes de métrologie (Document A).

Clinical laboratories shall have a perfect control of "in vitro diagnostic medical devices" to ensure the quality of their analytical results. This introductory presentation to a serie of documents of recommendations tackles the different standards of metrology concerning the requirements to reference materials, metrological traceability, metrological confirmation, management of measurement as well as uncertainty of measurement. The standards concerning clinical laboratories are then succinctly described.

[Biomarkers of tobacco smoke exposure]. / Les marqueurs spécifiques du tabagisme.

Tobacco smoking is a major risk factor for cancer, cardiovascular diseases and respiratory illnesses. Smoking is increasing among children and adolescents with subsequent consequences on the health. Furthermore, maternal tobacco smoking during pregnancy adversely affects prenatal growth. Nicotine, the most important tobacco alkaloid, is responsible for maintaining tobacco addiction. According to a recent Circulaire de la direction générale de la santé, nicotine dependence should be determined through questionnaires and quantitative estimate of nicotine metabolites. Nicotine blood level fluctuates and urinary nicotine excretion is of short duration. Nicotine is intensively metabolized in the liver and oxidized into cotinine. Urinary measurement of cotinine appears to be highly related with the degree of intoxication and to allow the differentiation between non exposed and exposed non-smokers. In order to check the present application of nicotine metabolites measurement, a survey was conducted in 340 smoking cessation units. Forty percent physicians (n = 137) answered the survey. For 17% of them, the quantification of nicotine metabolites is included in their daily practise and for 79%, guidelines about cotinine measurement should be given in France. Sixty-seven biologists answered the survey. Recommendations for immunoassay and HPLC determination of cotinine should be given as reported by 66 and 44% of them respectively. Indeed, urinary cotinine measurement with high performance liquid chromatography is highly sensitive and specific. However, immunoassays are more convenient. These two approaches are presently under investigation in order to provide guidelines for optimal use in various clinical situations. Traditional measures for nicotine dependence are the number of cigarettes smoked per day, nicotine intake expressed as mg per day, Fagerstr m questionnaire, expired air carbon monoxide, thiocyanates and cotinine levels in biological fluids. Urinary cotinine measurement is the most useful for the follow-up of smoking cessation including adjustment of nicotine replacement therapy, especially after a clinical event or for the follow-up of smoking pregnant women. It allows the detection of passive smoke exposure in children who are hospitalized for recurrent respiratory illnesses.

[Quality control of capillary blood measurements in clinical services: follow up by the biologist]. / Contrôle de qualité des analyseurs de glycémie capillaire dans les services hospitaliers: suivi par le biologiste.

In Bichat-Claude Bernard Hospital, the study of capillary glucose analyzers in the aim of uniformizing the selection of glucose meters, has shown the relevance of a standardized handling in order to obtain clinically interpretable results. It has been necessary to implement a quality follow up by the biologist. In the first stage, the biochemistry laboratory, with the clinical service supervisor and the supplier, has assured the training of the medical staff habilitated to use the meters and to carry out a quality control. In the second stage, the biologist implemented a monthly control on a total blood control sample, the stability of which has been checked after the necessary addition of glucose. Dosing of that sample, which is used as an external control, is carried out in parallel by the QID Precision glucose analyzer (Abbott) and by the portable Hemocue B Glucose (Vermed), which is selected as a comparison standard. This allows a monthly control of the accuracy of the meter. The condition of the equipment, as well as the weekly control follow up, validated by the nurse, is registered on a sheet prepared by the biologist. In partnership with Vermed, we have developed a processing software of the data stored in the Hemocue, allowing the automatic issue of a report summarizing the equipment condition and the data of weekly and monthly controls follow up. This report, signed by the biologist, is sent to every Service Manager and Supervising Nurse. On the basis of our one year experience, this practice has generated an efficient collaboration between the clinical services and the biochemistry laboratory, allowing to keep the quality of the capillary glucose measurements performed in inpatients.

Diagnostic value of ferritin and glycosylated ferritin in adult onset Still's disease.

OBJECTIVE: To determine the usefulness of serum ferritin and glycosylated ferritin (GF) levels in diagnosing adult onset Still's disease (AOSD). METHODS: We performed a retrospective multicenter study of 205 patients who had ferritin and GF assays in one hospital laboratory. Records of all patients were reviewed, and a standardized questionnaire used to extract all data available at the time of the assay. The clinicians' final diagnosis was also recorded. Patients were classified as having "certain AOSD" (based on Yamaguchi's criteria) or a control disease. The concordance of ferritin and GF levels with final diagnosis was evaluated. RESULTS: In total 49 AOSD and 120 control patients were eligible. The mean ferritin value was significantly higher in the AOSD group (4,752 +/- 9,599 microg/l) than in the control group (1,571 +/- 3,807 microg/l), p = 0.029. GF was significantly lower in AOSD patients (15.9 +/- 11.9%) than in the control group (31.5 +/- 18.7%), p < 0.001. The combination of a GF level of < or = 20% with ferritin above the upper limit of normal yielded a sensitivity of 70.5% and specificity of 83.2%. The combination of a GF level < or = 20% with ferritin 5 times normal produced a sensitivity of 43.2% and specificity of 92.9%. This latter combination allowed an AOSD diagnosis to be ruled out for 6 of the 8 control patients who met Yamaguchi's positive criteria. CONCLUSION: Ferritin and GF levels are powerful diagnostic markers of AOSD. They may be helpful in clinical practice for excluding differential diagnoses.

[Measurement of carotenoids by high pressure liquid chromatography: from difficulties to solutions]. / Dosage des caroténoïdes par chromatographie liquide haute performance: des difficultés aux solutions.

The measurement of serum carotenoids by HPLC has been largely improved during the last 10 years. However these techniques still require much time and skills, and direct application of published methods is rarely satisfying. We report here the difficulties that we met to transfer some HPLC methods described in the literature to our laboratories. We propose some solution to overcome the problems that we have encountered, our experience will perhaps help out other biologists. We reported also some results obtained in healthy populations.

Percentage of glycosylated serum ferritin remains low throughout the course of adult onset Still's disease.

OBJECTIVE: To determine the evolution of levels of total serum ferritin and percentage of the glycosylated form in patients with adult onset Still's disease (AOSD) at the time of diagnosis and during follow up. METHODS: All patients with AOSD were tested at the time of diagnosis and during follow up. Total serum ferritin levels were analysed by immunoassay, and the percentage of glycosylated ferritin was determined by methods using Sepharose-Con A. RESULTS: 14 patients (eight women, six men) with AOSD were enrolled. At the time of diagnosis, mean (SD) age was 36 (16) years. Mean initial total serum ferritin was 6350 (1300) microg/l (normal <250 microg/l). The mean initial percentage of glycosylated ferritin was 14.7 (13)% (normal >50%). Mean follow up time was 37 (35) months. At the time of the last examination all patients were in remission except one, who presented a chronic articular form. Total serum ferritin remained high in this single patient and was normal in the 13 others, with a mean of 98 (73) microg/l. In all patients the percentage of glycosylated ferritin remained low, with a mean of 16 (16)%. CONCLUSION: Total serum ferritin is a marker of the active phase of AOSD. The percentage of glycosylated ferritin is low both in the active phase and in remission. Further studies are needed to confirm these data and to determine their specificity for AOSD before considering any possible use of a low percentage of glycosylated ferritin as a diagnostic tool in suspected AOSD, especially when atypical or previously treated.

[Carotenoids: 1. Metabolism and physiology]. / Les caroténoïdes: I. Métabolisme et physiologie.

Carotenoids are a family of pigments with at least 600 members. They derive from lycopene after steps of cyclisation, dehydrogenation and oxidation. It is their chemical structure that determines their physiochemical properties and, in part, their biological activities. About 50 carotenoids can be found in human diet and about 20 of them have been found in plasma and tissues. There is no RDA (Recommended Daily Allowance) for carotenoids. Quantities of carotenoids in diet are difficult to estimate, partly because methods used for the establishment of food composition tables were not specific and sensitive enough. Also, given values do not always take into account variations due to season and region of culture. Absorption of beta-carotene in humans has been the subject of numerous studies but only very little is known about other carotenoids. In general, absorption depends on bioavailability from the food matrix and solubility in micelles. After absorption through passive diffusion, carotenoids follow the chylomicrons metabolism. They are taken up by the liver and released in the blood stream in lipoproteins (VLDL). Carotenoids with no-substituted beta-ionone cycles (alpha and beta-carotene and beta-cryptoxanthin) have provitamin A activity. Highest activity has been found for all-trans beta-carotene. Not all steps of vitamin A biosynthesis and metabolism of other carotenoids have been clarified yet. Besides their provitamin A activity, carotenoids have numerous biological functions. They are efficient scavengers of free radicals, particularly of 1O2. In vitro they have been shown to protect LDL. However, results in vivo are inconsistent. Other functions include enhancement of gap junctions, immunomodulation and regulation of enzyme activity involved in carcinogenesis.

[Acute respiratory Chlamydia pneumoniae infections in adults. Value of direct gene amplification diagnosis]. / Infections respiratoires aiguës de l'adulte à Chlamydia pneumoniae. Intérêt du diagnostic direct par amplification génique.

Chlamydia pneumoniae has been established recently as an important human respiratory pathogen. The aim of this study was to define the incidence of Chlamydia pneumoniae in acute respiratory infections by evaluating its presence in posterior nasopharyngeal aspirates or broncho-alveolar lavage specimens by polymerase chain reaction-hybridization (PCR-EIA) as well as the titres of specific antibodies in serum by a rELISA test and a micro-immunofluorescence (MIF) test. 68 adults patients were investigated. Eight patients (11.8%) were positive by either rELISA or PCR-EIA or both, with an infection rate of 5 patients with community-acquired pneumonia, 2 asthmatic patients and 1 patients with an exacerbation of chronic obstructive pulmonary disease. Serological evidence of acute infection was found in four of these patients with rELISA test and in three others with MIF test. PCR-EIA detected Chlamydia pneumoniae DNA in four patients, but there were concordant results with rELISA and PCR-EIA in only one patient. In conclusion, Chlamydia pneumoniae appears to be a common etiologic agent of acute respiratory infections in adults. The discrepancy between serological test and PCR-EIA results reflects the difficulties in routine laboratory diagnosis of Chlamydia pneumoniae. The ambiguous results of serological tests from a single serum sample assess the utility of PCR for prompt diagnosis. When PCR is negative or no feasible, a second serology to 15/21 days of interval is necessary. Further studies with optimised techniques must be developed.