Determination of Calcium, Magnesium, Sodium, and Potassium in Foodstuffs by Using a Microsampling Flame Atomic Absorption Spectrometric Method After Closed-Vessel Microwave Digestion: Method Validation

This paper describes a validation process in compliance with the NF/EN ISO/IEC 17025 standard for the determination of the macrominerals calcium, magnesium, sodium, and potassium in foodstuffs by microsampling with flame atomic absorption spectrometry after closed-vessel microwave digestion. The French Standards Commission (Agence Francaise de Normalisation) standards NF V03-110, NF EN V03-115, and XP T-90-210 were used to evaluate this method. The method was validated in the context of an analysis of the 1322 food samples of the second French Total Diet Study (TDS). Several performance criteria (linearity, LOQ, specificity, trueness, precision under repeatability conditions, and intermediate precision reproducibility) were evaluated. Furthermore, the method was monitored by several internal quality controls. The LOQ values obtained (25, 5, 8.3, and 8.3 mg/kg for Ca, Mg, Na, and K, respectively) were in compliance with the needs of the TDS. The method provided accurate results as demonstrated by a repeatability CV (CVr) of <7 and a reproducibility CV (CVR) of <12 for all the elements. Therefore, the results indicated that this method could be used in the laboratory for the routine determination of these four elements in foodstuffs with acceptable analytical performance.

An accurate and robust LC-MS/MS method for the quantification of chlorfenvinphos, ethion and linuron in liver samples

A method for the determination of chlorfenvinphos, ethion and linuron in liver samples by LC-MS/MS is described. Sample treatment was performed by using Sola™ polymeric reverse phase SPE cartridges after protein precipitation. Gradient elution using 10 mM ammonium formate in methanol (A) and 10 mM ammonium formate in water (B) was used for chromatographic separation of analytes on a Hypersil™ end-capped Gold PFP reverse phase column (100 mm × 2.1 mm, 3 μm). All analytes were quantified without interference, in positive ionization mode using multiple reaction monitoring (MRM) with chlorfenvinphos-d10 as internal standard. The whole procedure was validated according to the FDA guidelines for bioanalytical methods. The calibration curves for chlorfenvinphos, linuron and ethion compounds were linear over the concentration range of 0.005-2 μM (i.e. 0.0018-0.720 μg/mL, 0.0019-0.770 μg/mL and 0.0012-0.500 μg/mL respectively) with coefficients of determination higher than 0.998. A Lower limit of quantification of 0.005 μM was achieved for all analytes, i.e. 5.76, 6.08 and 3.84 μg/kg of liver for chlorfenvinphos, ethion and linuron respectively. Compounds extraction recovery rates ranged from 92.9 to 99.5% with a RSD of 2.3%. Intra- and inter-day accuracies were within 90.9 and 100%, and imprecision varied from 0.8 to 8.2%. Stability tests proved all analytes were stable in liver extracts during instrumental analysis (+12 °C in autosampler tray for 72 h) at the end of three successive freeze-thaw cycles and at -20 °C for up to 9 months. This accurate and robust analytical method is therefore suitable for contamination or metabolism studies.

Evidence of in vitro metabolic interaction effects of a chlorfenvinphos, ethion and linuron mixture on human hepatic detoxification rates

General population exposure to pesticides mainly occurs via food and water consumption. However, their risk assessment for regulatory purposes does not currently consider the actual co-exposure to multiple substances. To address this concern, relevant experimental studies are needed to fill the lack of data concerning effects of mixture on human health. For the first time, the present work evaluated on human microsomes and liver cells the combined metabolic effects of, chlorfenvinphos, ethion and linuron, three pesticides usually found in vegetables of the European Union. Concentrations of these substances were measured during combined incubation experiments, thanks to a new analytical methodology previously developed. The collected data allowed for calculation and comparison of the intrinsic hepatic clearance of each pesticide from different combinations. Finally, the results showed clear inhibitory effects, depending on the association of the chemicals at stake. The major metabolic inhibitor observed was chlorfenvinphos. During co-incubation, it was able to decrease the intrinsic clearance of both linuron and ethion. These latter also showed a potential for metabolic inhibition mainly cytochrome P450-mediated in all cases. Here we demonstrated that human detoxification from a pesticide may be severely hampered in case of co-occurrence of other pesticides, as it is the case for drugs interactions, thus increasing the risk of adverse health effects. These results could contribute to improve the current challenging risk assessment of human and animal dietary to environmental chemical mixtures.

Laparoscopic approach for rectosigmoidian resection in children

Abdominoperineal approach for rectosigmoidian resection,first imagined and performed in 1948 by Orwar Swenson,was the surgical technique that opened the pathway in the treatment of congenital megacolon (1). B. Duhamel (1956) and F. Soave (1964) intended to correct the postoperative complications appeared after the Duhamel technique and proposed surgical procedures that keep the aganglionic rectum in transit (2,3). In 1994 K. Bax reproduces the Duhamel procedure using laparoscopic approach (4). K.Georgeson, in 1995, reproduced the Swenson technique for rectosigmoidian resection using minimal invasive surgery (5).Today, this approach represents the most frequently used procedure for the radical treatment of congenital megacolon.

Total diet study on pesticide residues in France: levels in food as consumed and chronic dietary risk to consumers

Chronic dietary exposure to pesticide residues was assessed for the French population using a total diet study (TDS) to take into account realistic levels in foods as consumed at home (table-ready). Three hundred and twenty-five pesticides and their transformation products, grouped into 283 pesticides according to their residue definition, were sought in 1235 composite samples corresponding to 194 individual food items that cover 90% of the adult and child diet. To make up the composite samples, about 19,000 food products were bought during different seasons from 2007 to 2009 in 36 French cities and prepared according to the food preparation practices recorded in the individual and national consumption survey (INCA2). The results showed that 37% of the samples contained one or more residues. Seventy-three pesticides were detected and 55 quantified at levels ranging from 0.003 to 8.7mg/kg. The most frequently detected pesticides, identified as monitoring priorities in 2006, were the post-harvest insecticides pirimiphos-methyl and chlorpyrifos-methyl-particularly in wheat-based products-together with chlorpyrifos, iprodione, carbendazim and imazalil, mainly in fruit and fruit juices. Dietary intakes were estimated for each subject of INCA2 survey, under two contamination scenarios to handle left-censored data: lower-bound scenario (LB) where undetected results were set to zero, and upper-bound (UB) scenario where undetected results were set to the detection limit. For 90% of the pesticides, exposure levels were below the acceptable daily intake (ADI) under the two scenarios. Under the LB scenario, which tends to underestimate exposure levels, only dimethoate intakes exceeded the ADI for high level consumers of cherry (0.6% of children and 0.4% of adults). This pesticide, authorised in Europe, and its metabolite were detected in both cherries and endives. Under the UB scenario, that overestimates exposure, a chronic risk could not be excluded for nine other pesticides (dithiocarbamates, ethoprophos, carbofuran, diazinon, methamidophos, disulfoton, dieldrin, endrin and heptachlor). For these pesticides, more sensitive analyses of the main food contributors are needed in order to refine exposure assessment.

Li, Cr, Mn, Co, Ni, Cu, Zn, Se and Mo levels in foodstuffs from the Second French TDS

In 2006, the French Food Safety Agency (AFSSA) conducted the Second French Total Diet Study (TDS) to estimate dietary exposures to the main minerals and trace elements from 1319 samples of foods typically consumed by the French population. The foodstuffs were analysed by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave-assisted digestion. Occurrence data for lithium, chromium, manganese, cobalt, nickel, copper, zinc, selenium and molybdenum were reported and compared with results from the previous French TDS. The results indicate that the food groups presenting the highest levels of these essential trace elements were "tofu" (for Li, Mn, Ni, Cu, Zn and Mo),"fish and fish products" particularly "shellfish" (for Li, Co, Cu, Zn, Se and Mo), "sweeteners, honey and confectionery" particularly dark chocolate (for Cr, Mn, Co, Ni and Cu), "cereals and cereal products" (for Mn, Ni and Mo) and "ice cream" (for Cr, Co and Ni).

Pb, Hg, Cd, As, Sb and Al levels in foodstuffs from the 2nd French total diet study

In 2006, the French Food Safety Agency (AFSSA) conducted the second French total diet study (TDS) to estimate dietary exposures of main minerals and trace elements from 1319 samples of foods habitually consumed by the French population. The foodstuffs were analysed by ICP-MS after microwave-assisted digestion. Contamination data for lead, mercury, cadmium, arsenic, antimony and aluminium were reported and compared with results from the previous French total diet study. The results are comparable with those from the rest of Europe. "Fish and fish products" and "sweeteners, honey and confectionery" were the food groups showing the highest cumulated contents in Pb, Hg, Cd, As, Al and Sb. However, observed levels remained low and were generally well below the maximum levels set by the current European regulation for lead, cadmium and mercury.

Determination of calcium, magnesium, sodium, and potassium in foodstuffs by using a microsampling flame atomic absorption spectrometric method after closed-vessel microwave digestion: method validation

This paper describes a validation process in compliance with the NFIEN ISO/IEC 17025 standard for the determination of the macrominerals calcium, magnesium, sodium, and potassium in foodstuffs by microsampling with flame atomic absorption spectrometry after closed-vessel microwave digestion. The French Standards Commission (Agence Francaise de Normalisation) standards NF V03-110, NF EN V03-115, and XP T-90-210 were used to evaluate this method. The method was validated in the context of an analysis of the 1322 food samples of the second French Total Diet Study (TDS). Several performance criteria (linearity, LOQ, specificity, trueness, precision under repeatability conditions, and intermediate precision reproducibility) were evaluated. Furthermore, the method was monitored by several internal quality controls. The LOQ values obtained (25, 5, 8.3, and 8.3 mg/kg for Ca, Mg, Na, and K, respectively) were in compliance with the needs of the TDS. The method provided accurate results as demonstrated by a repeatability CV (CVr) of < 7% and a reproducibility CV (CVR) of < 12% for all the elements. Therefore, the results indicated that this method could be used in the laboratory for the routine determination of these four elements in foodstuffs with acceptable analytical performance.

Determination of traces of fipronil and its metabolites in pollen by liquid chromatography with electrospray ionization-tandem mass spectrometry

Fipronil is a pesticide suspected of having harmful effects on honey bees at microgram per kilogram levels. Considering the lack of methodology, it thus appeared to be necessary to develop a method for the determination of the lowest amounts of fipronil and its metabolites in pollen. This paper describes a new analytical method with a limit of quantification (LOQ) of 0.1 microg/kg for a representative sample weight of 5 g. In the case of a field study, this tool was used for checking the possible existence of fipronil and/or metabolites in pollen samples, but none of them contained residues higher than the LOQ. This three-step rapid method uses liquid-solid solvent extraction with mechanical grinding, followed by liquid-liquid partitioning and Florisil solid-phase extraction for the two cleanup steps. The quantification is made by liquid chromatography with electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Indeed, combined with an adequate sample treatment, this technique offers good sensitivity and selectivity in such a complex matrix. The method has given good recoveries of 74-104% with relative standard deviations of 5.6-18.2%.

Atherosclerosis in amputated legs of patients with and without diabetes mellitus

BACKGROUND

The aim of this study was to compare the histomorphologic appearance of atherosclerosis in amputated legs of diabetic and non-diabetic patients.

METHODS

Twenty-eight legs amputated below the knee for chronic ischaemia were studied. Fourteen legs were amputated in patients with diabetes (10 Type II, 4 nonclassified) and 14 in non-diabetics. The mean age of patients at the time of the amputation was 63.3 years in diabetics and 63.9 years in non-diabetics. Samples were taken from the main arteries at the following levels: the midleg, 5 cm above the ankle, 3 cm below the ankle and 10 cm below the ankle. Cross-sections of the arteries were examined with light microscopy and the severity of the occlusive disease determined using morphometric analysis. Medial calcification and chronic inflammation were assessed semiquantitatively.

RESULTS

Arteries at 5 cm above the ankle were more severely stenotic in diabetics than in non-diabetics (p<0.05). In both diabetics and non-diabetics the posterior tibial and plantar arteries appeared to be the most stenotic. Medial calcification tended to be more prominent in diabetics than in non-diabetics. Chronic inflammation in the arterial wall occurred at the same degree in diabetics and non-diabetics. In non-diabetics chronic inflammation was more severe in the posterior tibial and plantar arteries than in the anterior tibial and dorsalis pedis arteries (p<0.04). Chronic arterial inflammation correlated with the severity of chronic arterial occlusive disease (p<0.0002).

CONCLUSIONS

In diabetics occlusive disease in amputated legs is more severe in arteries above the ankle than in non-diabetics. However, no difference was demonstrated in this series in arteries of the ankle and foot. Diabetics are likely to have more medial calcification in the arteries than non-diabetics. Chronic inflammation in the arterial wall is associated with more severe stenosis.

Surgical anatomy for endoscopic subfascial division of perforating veins

PURPOSE

This study was undertaken to define the surgical anatomy of the medial perforating veins (PVs) of the leg and to provide information on how to gain access to all medial PVs from the superficial posterior compartment during a subfascial endoscopic procedure.

METHODS

The venous anatomy of 40 limbs (from 23 cadavers) were studied. Medial PVs located between the ankle and the tibial tuberosity were dissected. None of the subjects had pathologic evidence of venous disease. Each PV's type (direct or indirect), size (< 1 mm, 1 to 2 mm, > 2 mm), location (distances from ankle [D1], and tibia [D2]), and accessibility from the superficial posterior compartment were recorded.

RESULTS

Five hundred fifty-two PVs were identified (mean, 13.8; range, 7 to 22). Two hundred eighty-seven PVs (52%) directly connected the superficial with the deep systems, 228 (41%) were indirect muscle perforators, and 37 PVs (7%) were undetermined. One hundred thirty-seven PVs (25%) were > 2 mm. Sixty-three percent of PVs were accessible from the superficial posterior compartment. In the distal half of the leg, two groups of direct PVs could be identified (Cockett II: D1, 7 to 9 cm; Cockett III: D1, 10 to 12 cm). In the proximal half of the leg, paratibial direct PVs (D2 < or = 1 cm) were found clustered in three groups (D1, 18 to 22 cm; D1, 23 to 27 cm; D1, 28 to 32 cm).

CONCLUSIONS

Our study confirmed the presence of the Cockett II and III PVs and three groups of proximal paratibial PVs, including the "24-cm" perforators. Two thirds of the medial direct PVs are accessible for endoscopic division from the superficial posterior compartment. To divide paratibial PVs, however, incision of the paratibial deep fascia is frequently required.

Usefulness of exercise-induced ST-segment depression in the inferior leads during exercise testing as a marker for coronary artery disease

Multiple lead systems are shown to have a higher sensitivity than that of single leads for detecting coronary artery disease (CAD) during exercise testing, but the value of ST-segment depression isolated to the inferior leads is questionable. To ascertain the diagnostic accuracy of inferior limb lead II compared with that of precordial lead V5, a retrospective analysis of 173 men was performed (108 in a training population and 65 in a validation cohort). All patients had a standard exercise test and underwent diagnostic coronary angiography within 15 days of the exercise test (range 1 to 65). Sixty-three patients had greater than or equal to 1 coronary stenoses greater than or equal to 70%, or left main lesion greater than or equal to 50%, whereas 45 patients in the training population did not. Exclusion criteria were female sex, left ventricular hypertrophy, left bundle branch block or resting ST-segment depression on the baseline electrocardiogram, previous myocardial infarction or revascularization procedures, and any significant valvular or congenital heart disease. Lead V5 had a better combination of sensitivity (65%) and specificity (84%) (chi-square = 24.11; p less than 0.001) than that of lead II (sensitivity 71%, specificity 44%) (chi-square = 2.25; p = 0.13) at a single cut point, and this improved specificity was substantial (95% confidence interval for observed difference 22 to 58%). Receiver-operating characteristic curve analysis also revealed that lead V5 (area = 0.759) was markedly superior to lead II (area = 0.582) over multiple cut points (z = 3.032; 2p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural aspects of freeze-fractured and etched elastin

The ultrastructural organization of fresh and purified elastin from beef ligamentum nuchae was studied by means of the freeze-etching technique. Both fresh and purified elastin showed a regular three-dimensional network of filaments which seemed to be composed of a sequence of globular subunities. There were also areas, along the regular network, in which ridges of various lengths, packed with perpendicular side filaments, were visible. In replicas of deep-etched and rotary-shadowed specimens, a thicker and more defined three-dimensional network was observable. A great variability in appearance among the globular subunits of the filaments was noticed which was at least partially due to the etching treatment. By means of computerized simulation of replicas of various hypothetically collapsed globular structures, we obtained patterns which were superimposable on those obtained in the replicas of the specimens analyzed. It is thus assumed that each globular subunit of the filament, being subjected to collapsing, has a less dense central core.

Dose-related effects of nebulized metaproterenol in asthmatic children

The dose-related effects of inhaled 5% metaproterenol solution in asthmatic children between the ages of six and 12 years with acute bronchospasm were evaluated. Tests included FEV1.0, FEF25-75, and PEFR. For entry into the study, subjects were required to have an FEV1.0 or an FEF25-75 less than 80% of the child's predicted normal value based on height and race. Sixty children were randomly assigned in double-blind fashion to receive one of four different doses of 5% metaproterenol inhalant solution: 0.0 ml (placebo), 0.1 ml, 0.2 ml, or 0.3 ml. Drug efficacy was assessed by spirometry using a DeVilbiss Surveyor I spirometer. Spirometry was performed prior to inhalation of the test dose (baseline) and four times after inhalation: immediately after and 15, 30, and 60 minutes after inhalation. Patients in the three treated groups had significantly higher peak post-dose FEV1.0 and FEF25-75 than the placebo group but were not significantly different from one another. There was a significant relationship between dose and incidence of side effects. These results suggest that 0.1 ml (5 mg) of nebulized metaproterenol may provide as much bronchodilatation as higher doses with fewer side effects.

Physicochemical and ultrastructural properties of cholesterol esters bound to elastin

Physicochemical and ultrastructural properties of cholesterol ester complexes of fibrous elastin and of K-elastin were studied using differential scanning calorimetry (DSC) and electron-microscopy. The number of molecules of the different fatty acids retained in these elastin complexes varied between large limits according to the nature of the fatty acid of the cholesterol ester, ranging from 0.1 microgram/200 mg of elastin for cholesterol arachidonate to 48 micrograms/200 mg elastin for cholesterol palmitate. The ultrastructural studies confirmed the association of cholesterol esters with fibrous elastin and soluble K-elastin. The DSC-data showed that the temperature of transition between the crystalline and the liquid crystalline state shifts towards higher temperatures (well above body temperature) when cholesterol esters are bound to elastin: no liquid crystalline mesophase was observed in cholesterol oleate or linoleate-elastin complexes at 37 degrees C; melting of the crystalline structures took place at 51 degrees C and at 42 degrees C for the cholester Holeate and linoleate-elastin complexes respectively. These results indicate that in the elastin-bound form the crystalline-liquid crystalline transition is inhibited. The "stabilization" of the crystalline structure of cholesterol esters by fibrous elastin may be of biological significance and account for the crystalline deposits seen in advanced atherosclerotic lesions at sites of elastic fiber breakdown.

Influence of anthocyanoside treatment on the cholesterol-induced atherosclerosis in the rabbit

We have studied the effect of treatment with anthocyanosides from Vaccinium myrtillis on cholesterol-induced atheroma of rabbits. We have found that the drug did not modify the serum cholesterol levels, but decreased the proliferation of the intima the extracellular matrix production the calcium and lipid deposition in the aorta, and the DNA and lipid contents. The alterations in the biochemical composition of the isolated brain microvessels were also diminished. The following mechanism may explain the protective action of the treatment: the collagen of the vessel walls participates in the control of vascular permeability. This permeability is increased by a cholesterol-rich diet. The protective drug interacts with collagen, increasing its cross-links, thus diminishing the permeability in small, as well as in large blood vessels.

Influence of beta-amino-propionitrile on elastogenesis in the chick embryo (light and electron microscopic study)

Beta-amino-propionitrile was administered in a single dose into the chorioallantoic cavity of 14 days old chick embryos. The effects on the elastic fibre production were examined on the 3rd or 7th day following the injection. By light microscopy dissecting aneurysm, aortic ruptures were found. The elastic fibres were poorly developed and exhibited irregularities and structural anomalies. Electron microscopically we observed reduction of the number or complete absence of elastic aggregates and fibres. The elastic structures exhibited abnormal phosphotungstic acid binding. This was considered as a sign for disturbances in the development of cross linkages and in the incorporation of elastin into the elastic fibres.

Composition and macromolecular structure of intima in normal and arteriosclerotic human aorta

Proteoglycanes, glycoprotein, fibrous collagen and elastin proteins were isolated from normal human aortic intima and from sclerotic lipid and calcium plaques and examined by electron microscope and thermal analysis. Differences between the structure and compositon of normal human aortic wall and aortic lipid plaques are chiefly found in the proteoglycan containing fraction. The calcium plaque shows structural changes in the fibrillar protein components.