Evidence for Endogenous Collagen in Fossil Bone.

Reports of proteins in fossilized bones have been a subject of controversy in the scientific literature because it is assumed that fossilization results in the destruction of all organic components. In this paper, a novel combination of analytical techniques is used to address this question for an exceptionally well-preserved sacrum excavated from the Upper Cretaceous strata of the South Dakota Hell Creek Formation. Cross-polarized light microscopy (XPol) shows birefringence consistent with collagen presence.

Effects of polychlorinated biphenyl/dioxin exposure and feeding type on infants' mental and psychomotor development.

Objective: To evaluate the effects of in utero and lactational exposure to polychlorinated biphenyls (PCBs) and dioxins on the mental and psychomotor development of infants.

Design: Prenatal PCB exposure was estimated from the levels in maternal plasma during the last month of pregnancy. Postnatal PCB and dioxin exposure of breastfed infants was calculated from levels in human milk samples and the duration of breastfeeding.

Neurological condition in 18-month-old children perinatally exposed to polychlorinated biphenyls and dioxins.

The neurological optimality of 418 Dutch children was evaluated at the age of 18 months, in order to determine whether prenatal and breast milk mediated exposure to polychlorinated biphenyls (PCBs) and dioxins affected neurological development. Half of the infants were breast-fed, the other half were formula-fed. PCB concentrations in cord and maternal plasma were used as a measure of prenatal exposure to PCBs.

Perinatal exposure to polychlorinated biphenyls and dioxins and its effect on neonatal neurological development.

Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs)) are widespread environmental contaminants which are neurotoxic in animals. Perinatal exposure to PCBs, PCDDs, and PCDFs occurs prenatally via the placenta and postnatally via breast milk. To investigate whether such an exposure affects the neonatal neurological condition, the neurological optimality of 418 Dutch newborns was evaluated with the Prechtl neurological examination.

Effects of polychlorinated biphenyls (PCBs) and dioxins on growth and development.

Polychlorinated biphenyls (PCBs) and dioxins are potentially toxic compounds which occur widely in the environment. Their effects on the growth and development of infants at the levels currently found in highly industrialised western countries is not well known. This Dutch multicenter study, combining animal and human studies, tries to answer this question.

Dioxin and PCB levels in blood and human milk in relation to living areas in The Netherlands.

Dioxins and polychlorinated biphenyls (PCBs) are ubiquitous toxic compounds in the environment. Negative influences of these compounds on the health status of human beings have been described. Especially susceptible might be the fetus, which is exposed in utero, and the newborn breast-fed infant, since both are exposed to relatively high levels of dioxins and PCBs during a critical period of organ growth and development.

The Dutch PCB/Dioxin Study. Development of a method for the determination of dioxins, planar and other PCBs in human milk.

A method for the determination of dioxins, planar PCBs and other PCBs in human milk is described. The work is part of a big Dutch project, (seven institutes participates) in which 400 human milk samples from two areas (Rotterdam and Groningen) taken at two different times (10 and 42 days) after delivery had to be analysed for planar PCBs, dioxins and other PCBs (1st sampling) and only other PCBs (2nd sampling). Planar compounds are determined with GC/HRMS, other PCBs with GC/ECD.

Effects of dioxins and polychlorinated biphenyls on thyroid hormone status of pregnant women and their infants.

Dioxins [polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF)] and polychlorinated biphenyls (PCB) are potentially hazardous compounds. Animal studies have demonstrated that PCDD, PCDF, and PCB can alter thyroid hormone homeostasis. We investigated thyroid hormone levels in 105 mother-infant pairs.

The development of five animal feed reference materials, certified for their aflatoxin B1 content.

The development of three peanut meal and two compound feed reference materials and the certification of their aflatoxin B1 content is described. The materials were prepared and certified within the Measurements and Testing Programme of the Commission of the European Communities as part of a broad activity to improve accuracy and agreement of results of measurements on food and agriculture. RM 262 (peanut meal) was prepared from uncontaminated peanut products.

Liquid chromatographic determination of aflatoxin M1 in milk powder using immunoaffinity columns for cleanup: interlaboratory study.

A liquid chromatographic method for determining low aflatoxin M1 concentrations in milk was evaluated in an International Dairy Federation (IDF) interlaboratory study. The study involved 16 participants from 11 countries. The method, chosen after a comparison of several methods by a preparatory group, uses an immunoaffinity column for cleanup.

Simultaneous determination of planar chlorobiphenyls and polychlorinated dibenzo-p-dioxins and -furans in Dutch milk using isotope dilution and gas chromatography-high-resolution mass spectrometry.

A method is described for the simultaneous determination of planar chlorobiphenyls and dioxins in milk using isotope dilution and gas chromatography-high-resolution mass spectrometry (GC-MS). The method is based on gel permeation chromatography, alumina clean-up and carbon chromatography and is highly automated, making a high sample throughput possible. Data on recovery, accuracy and reproducibility of results obtained with quality control samples are presented.

Multimycotoxin detection and clean-up method for aflatoxins, ochratoxin and zearalenone in animal feed ingredients using high-performance liquid chromatography and gel permeation chromatography.

A sensitive and reliable method is described for the determination of aflatoxins B1, B2, G1 and G2, ochratoxin A and zearalenone in animal feed ingredients. A multi-toxin extraction and clean-up procedure is used, with dichloromethane-1 M hydrochloric acid (10:1) being used for the extraction and gel permeation chromatography being used for the clean-up. The liquid chromatographic method developed for the separation of the six mycotoxins involves gradient elution with a reversed-phase C18 column and fluorescence detection.

Nutrients and contaminants in human milk from mothers on macrobiotic and omnivorous diets.

The effect of alternative dietary habits and prolonged lactation on the nutrient and contaminant concentrations in human milk was studied. The study sample consisted of mothers on macrobiotic diets, containing little or no diary products and meat, at 2-3 months postpartum (n = 9) and 9-13 months postpartum (n = 12), and mothers on omnivorous diets at 2-3 months postpartum (n = 10). Protein and zinc concentrations in breast-milk from macrobiotic mothers decreased with stage of lactation.

Automated clean-up procedure for the gas chromatographic-high-resolution mass spectrometric determination of polychlorinated dibenzo-p-dioxins and dibenzofurans in milk.

A highly automated extraction and clean-up method for polychlorinated dibenzodioxins and polychlorinated dibenzofurans is described. The method includes the use of gel permeation chromatography, alumina clean-up and porous graphitized carbon chromatography, followed by analysis by gas chromatography-high-resolution mass spectrometry. The procedure allows for the analysis of six milk samples per day in addition to two quality control samples and a blank.

[Polychlorobiphenyls in human milk, adipose tissue, plasma and umbilical cord blood; levels and correlates].

In a longitudinal study involving 17 women, PCB concentrations (PCBs 138, 153 and 180) were determined in cord blood (17 newborns), breast milk (10 women), maternal adipose tissue (8 women), maternal plasma collected during the last trimester of pregnancy (17 women) and maternal plasma collected 10 days post partum (7 women). Significant correlations were found (p less than 0.05) between PCB levels in cord blood, breast milk and adipose tissue and maternal plasma collected before birth, and between breast milk and maternal plasma collected post partum.

Automated liquid chromatographic determination of aflatoxin M1 in milk using on-line dialysis for sample preparation.

A procedure has been developed for the automated isolation of aflatoxin M1 from decreamed milk. The method uses on-line stopped flow dialysis and subsequent trace enrichment on a reverse-phase column. After a back-flush to the analytical liquid chromatography column, aflatoxin M1 is determined with fluorescence detection.

Tandem capillary gas chromatography in pesticide residue analysis.

Maximum residue levels of pesticides in food and feed are often below the 0.1 ppm level. On capillary columns, the maximum injection volumes are 5-10 microliters in the splitless mode, although of course some (acceptable) overloading of the GC column occurs.

Capillary gas chromatographic determination of some chlorobiphenyls in eel fat: interlaboratory study.

A method for determination of 6 individual chlorobiphenyls in eel fat, based on saponification of the sample and determination with capillary gas chromatography, was studied collaboratively. Eleven laboratories submitted analytical results in duplicate for 6 individual chlorobiphenyls on 2 naturally contaminated eel fat samples. The reproducibility coefficient of variation was about 14% at the 1 mg/kg level for each chlorobiphenyl compound and about 23% at the 0.

Rapid determination of aflatoxin B1 in Dutch feeding stuffs by high-performance liquid chromatography and post-column derivatization.

Concentrated feeding-stuff samples are extracted with chloroform. Clean-up of the extract is carried out by applying six samples in the middle of a thin-layer plate and developing it first with diethylether. After drying and cutting off a part of the plate, development is carried out in the opposite direction with a mixture of chloroform, acetone and water.

Procedure for the gas chromatographic-mass spectrometric confirmation of some exogenous growth-promoting compounds in the urine of cattle.

As gas chromatography-mass spectrometry is the most conclusive confirmation technique available today for the detection of ppb levels of anabolics in the urine of cattle, the following procedure was used. The urine is hydrolysed with Helix pomatia intestinal juice, extracted, and the extract cleaned by gel-permeation chromatography or with Extrelut. In one fraction are eluted diethylstilboestrol, dienoestrol, hexoestrol, methyltestosterone, ethinyloestradiol, zeranol and trenbolone.

Quantitative determination of specified chlorobiphenyls in fish with capillary gas chromatography and its use for monitoring and tolerance purposes.

A gel permeation (GPC) clean-up procedure of fish samples in combination with capillary gas chromatography is used for the determination of individual chlorobiphenyls. The described method is compared with a more universal method based on saponification. Starting from a tolerance for PCB's expressed as a technical Aroclor, tolerance for some specified individual chlorobiphenyls are derived.

Liquid chromatographic determination of natamycin in cheese at residue levels.

A high performance liquid chromatographic method, with special reference to the cleanup procedure, is described for the measurement of natamycin in cheese. Co-extracted fats and proteins are removed by cooling the methanol extract of the cheese. Amounts as low as 1 ng natamycin can be detected; the limit of determination is better than 0.